diff --git a/.ci/bwcVersions b/.ci/bwcVersions
index ddc36af48d674..6488fda153e91 100644
--- a/.ci/bwcVersions
+++ b/.ci/bwcVersions
@@ -38,4 +38,40 @@ BWC_VERSION:
   - "1.2.5"
   - "1.3.0"
   - "1.3.1"
-  - "1.4.0"
+  - "1.3.2"
+  - "1.3.3"
+  - "1.3.4"
+  - "1.3.5"
+  - "1.3.6"
+  - "1.3.7"
+  - "1.3.8"
+  - "1.3.9"
+  - "1.3.10"
+  - "1.3.11"
+  - "1.3.12"
+  - "1.3.13"
+  - "1.3.14"
+  - "2.0.0"
+  - "2.0.1"
+  - "2.0.2"
+  - "2.1.0"
+  - "2.1.1"
+  - "2.2.0"
+  - "2.2.1"
+  - "2.2.2"
+  - "2.3.0"
+  - "2.3.1"
+  - "2.4.0"
+  - "2.4.1"
+  - "2.4.2"
+  - "2.5.0"
+  - "2.5.1"
+  - "2.6.0"
+  - "2.6.1"
+  - "2.7.0"
+  - "2.7.1"
+  - "2.8.0"
+  - "2.8.1"
+  - "2.9.0"
+  - "2.9.1"
+  - "2.10.0"
diff --git a/.ci/dockerOnLinuxExclusions b/.ci/dockerOnLinuxExclusions
index 8061248a87df4..dd518c7043e2f 100644
--- a/.ci/dockerOnLinuxExclusions
+++ b/.ci/dockerOnLinuxExclusions
@@ -12,4 +12,4 @@ ol-7.7
 sles-12.3 # older version used in Vagrant image
 sles-12.5
 sles-15.1
-sles-15.2
\ No newline at end of file
+sles-15.2
diff --git a/.ci/documentation/issue.md b/.ci/documentation/issue.md
new file mode 100644
index 0000000000000..c34905605b2f6
--- /dev/null
+++ b/.ci/documentation/issue.md
@@ -0,0 +1,11 @@
+**Is your feature request related to a problem?**
+A new feature has been added.
+
+**What solution would you like?**
+Document the usage of the new feature.
+
+**What alternatives have you considered?**
+N/A
+
+**Do you have any additional context?**
+See please 
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 5dfa9099866d1..4fa118e8486f1 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1,3 +1 @@
-# This should match the owning team set up in https://github.com/orgs/opensearch-project/teams
-*   @opensearch-project/opensearch-core
-
+*   @reta @anasalkouz @andrross @Bukhtawar @CEHENKLE @dblock @gbbafna @setiah @kartg @kotwanikunal @mch2 @nknize @owaiskazi19 @peternied @Rishikesh1159 @ryanbogan @saratvemulapalli @shwetathareja @dreamer-89 @tlfeng @VachaShah @dbwiddis @sachinpkale @sohami @msfroh
diff --git a/.github/ISSUE_TEMPLATE/failed_check.md b/.github/ISSUE_TEMPLATE/failed_check.md
new file mode 100644
index 0000000000000..71508c9f5bd43
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/failed_check.md
@@ -0,0 +1,8 @@
+---
+title: '[AUTOCUT] Gradle Check Failure on push to {{ env.branch_name }}'
+labels: '>test-failure, bug, autocut'
+---
+
+Gradle check has failed on push of your commit {{ env.pr_from_sha }}.
+Please examine the workflow log {{ env.workflow_url }}.
+Is the failure [a flaky test](https://github.com/opensearch-project/OpenSearch/blob/main/DEVELOPER_GUIDE.md#flaky-tests) unrelated to your change?
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index ca972d1b242e3..1f4d309e44a4c 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -599,6 +599,11 @@ updates:
     package-ecosystem: gradle
     schedule:
       interval: weekly
+  - directory: /plugins/crypto-kms/
+    open-pull-requests-limit: 1
+    package-ecosystem: gradle
+    schedule:
+      interval: weekly
   - directory: /qa/
     open-pull-requests-limit: 1
     package-ecosystem: gradle
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index d7981b5113972..3db0555e7da76 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -1,15 +1,17 @@
 ### Description
 [Describe what this change achieves]
- 
+
 ### Issues Resolved
 [List any issues this PR will resolve]
- 
+
 ### Check List
 - [ ] New functionality includes testing.
   - [ ] All tests pass
 - [ ] New functionality has been documented.
   - [ ] New functionality has javadoc added
-- [ ] Commits are signed per the DCO using --signoff 
+- [ ] Commits are signed per the DCO using --signoff
+- [ ] Commit changes are listed out in CHANGELOG.md file (See: [Changelog](../blob/main/CONTRIBUTING.md#changelog))
+- [ ] GitHub issue/PR created in [OpenSearch documentation repo](https://github.com/opensearch-project/documentation-website) for the required public documentation changes (#[Issue/PR number])
 
 By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
 For more information on following Developer Certificate of Origin and signing off your commits, please check [here](https://github.com/opensearch-project/OpenSearch/blob/main/CONTRIBUTING.md#developer-certificate-of-origin).
diff --git a/.github/workflows/auto-release.yml b/.github/workflows/auto-release.yml
new file mode 100644
index 0000000000000..252cbda1392f8
--- /dev/null
+++ b/.github/workflows/auto-release.yml
@@ -0,0 +1,29 @@
+name: Releases
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: GitHub App token
+        id: github_app_token
+        uses: tibdex/github-app-token@v2.1.0
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.APP_PRIVATE_KEY }}
+          installation_id: 22958780
+      - name: Get tag
+        id: tag
+        uses: dawidd6/action-get-tag@v1
+      - uses: actions/checkout@v4
+      - uses: ncipollo/release-action@v1
+        with:
+          github_token: ${{ steps.github_app_token.outputs.token }}
+          bodyFile: release-notes/opensearch.release-notes-${{steps.tag.outputs.tag}}.md
diff --git a/.github/workflows/backport.yml b/.github/workflows/backport.yml
index e47d8d88c0243..e190867fbaab5 100644
--- a/.github/workflows/backport.yml
+++ b/.github/workflows/backport.yml
@@ -7,22 +7,33 @@ on:
 
 jobs:
   backport:
+    name: Backport
     runs-on: ubuntu-latest
+    # Only react to merged PRs for security reasons.
+    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
+    if: >
+      github.event.pull_request.merged
+      && (
+        github.event.action == 'closed'
+        || (
+          github.event.action == 'labeled'
+          && contains(github.event.label.name, 'backport')
+        )
+      )
     permissions:
       contents: write
       pull-requests: write
-    name: Backport
     steps:
       - name: GitHub App token
         id: github_app_token
-        uses: tibdex/github-app-token@v1.5.0
+        uses: tibdex/github-app-token@v2.1.0
         with:
           app_id: ${{ secrets.APP_ID }}
           private_key: ${{ secrets.APP_PRIVATE_KEY }}
           installation_id: 22958780
 
       - name: Backport
-        uses: VachaShah/backport@v1.1.4
+        uses: VachaShah/backport@v2.1.0
         with:
           github_token: ${{ steps.github_app_token.outputs.token }}
-          branch_name: backport/backport-${{ github.event.number }}
+          head_template: backport/backport-<%= number %>-to-<%= base %>
diff --git a/.github/workflows/changelog_verifier.yml b/.github/workflows/changelog_verifier.yml
new file mode 100644
index 0000000000000..9456fbf8b4ca0
--- /dev/null
+++ b/.github/workflows/changelog_verifier.yml
@@ -0,0 +1,19 @@
+name: "Changelog Verifier"
+on:
+  pull_request:
+    types: [opened, edited, review_requested, synchronize, reopened, ready_for_review, labeled, unlabeled]
+
+jobs:
+  # Enforces the update of a changelog file on every pull request
+  verify-changelog:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - uses: dangoslen/changelog-enforcer@v3
+        with:
+          skipLabels: "autocut, skip-changelog"
diff --git a/.github/workflows/check-compatibility.yml b/.github/workflows/check-compatibility.yml
new file mode 100644
index 0000000000000..d93f7e73b91e7
--- /dev/null
+++ b/.github/workflows/check-compatibility.yml
@@ -0,0 +1,69 @@
+---
+name: Check Compatibility
+
+on:
+  pull_request_target
+
+jobs:
+  check-compatibility:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    permissions:
+      contents: read
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Increase swapfile
+        run: |
+          sudo swapoff -a
+          sudo fallocate -l 10G /swapfile
+          sudo chmod 600 /swapfile
+          sudo mkswap /swapfile
+          sudo swapon /swapfile
+          sudo swapon --show
+
+      - name: Run compatibility task
+        run: ./gradlew checkCompatibility -i | tee $HOME/gradlew-check.out
+
+      - name: Get results
+        run: |
+          echo '## Compatibility status:' > "${{ github.workspace }}/results.txt"
+          echo "Checks if related components are compatible with change $(git rev-parse --short HEAD)" >> "${{ github.workspace }}/results.txt"
+          echo "### Incompatible components" >> "${{ github.workspace }}/results.txt" && grep -e 'Incompatible component' $HOME/gradlew-check.out | sed -e 's/Incompatible component: \[\(.*\)\]/- \1/' >> "${{ github.workspace }}/results.txt"
+          echo "### Skipped components"      >> "${{ github.workspace }}/results.txt" && grep -e 'Skipped component'      $HOME/gradlew-check.out | sed -e 's/Skipped component: \[\(.*\)\]/- \1/'      >> "${{ github.workspace }}/results.txt"
+          echo "### Compatible components"   >> "${{ github.workspace }}/results.txt" && grep -e 'Compatible component'   $HOME/gradlew-check.out | sed -e 's/Compatible component: \[\(.*\)\]/- \1/'   >> "${{ github.workspace }}/results.txt"
+
+      - name: Upload results
+        uses: actions/upload-artifact@v3
+        with:
+          name: results.txt
+          path: ${{ github.workspace }}/results.txt
+
+  add-comment:
+    needs: [check-compatibility]
+    permissions:
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download results
+        uses: actions/download-artifact@v3
+        with:
+          name: results.txt
+
+      - name: Find Comment
+        uses: peter-evans/find-comment@v2
+        id: fc
+        with:
+          issue-number: ${{ github.event.number }}
+          comment-author: 'github-actions[bot]'
+          body-includes: 'Compatibility status:'
+
+      - name: Add comment on the PR
+        uses: peter-evans/create-or-update-comment@v3
+        with:
+          comment-id: ${{ steps.fc.outputs.comment-id }}
+          issue-number: ${{ github.event.number }}
+          body-path: results.txt
+          edit-mode: replace
diff --git a/.github/workflows/copy-linked-issue-labels.yml b/.github/workflows/copy-linked-issue-labels.yml
new file mode 100644
index 0000000000000..33b5e92dc10da
--- /dev/null
+++ b/.github/workflows/copy-linked-issue-labels.yml
@@ -0,0 +1,21 @@
+name: Copy labels from linked issues
+on:
+  pull_request_target:
+    types: [opened, edited, review_requested, synchronize, reopened, ready_for_review]
+
+jobs:
+  copy-issue-labels:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    runs-on: ubuntu-latest
+    permissions:
+      issues: read
+      contents: read
+      pull-requests: write
+    steps:
+      - name: copy-issue-labels
+        uses: michalvankodev/copy-issue-labels@v1.3.0
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          labels-to-exclude: |
+            untriaged
+            triaged
diff --git a/.github/workflows/create-documentation-issue.yml b/.github/workflows/create-documentation-issue.yml
new file mode 100644
index 0000000000000..df63847f8afca
--- /dev/null
+++ b/.github/workflows/create-documentation-issue.yml
@@ -0,0 +1,41 @@
+name: Create Documentation Issue
+on:
+  pull_request:
+    types:
+      - labeled
+env:
+  PR_NUMBER: ${{ github.event.number }}
+
+jobs:
+  create-issue:
+    if: ${{ github.event.label.name == 'needs-documentation' }}
+    runs-on: ubuntu-latest
+    name: Create Documentation Issue
+    steps:
+      - name: GitHub App token
+        id: github_app_token
+        uses: tibdex/github-app-token@v2.1.0
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.APP_PRIVATE_KEY }}
+          installation_id: 22958780
+
+      - name: Checkout code
+        uses: actions/checkout@v4
+        
+      - name: Edit the issue template
+        run: |
+          echo "https://github.com/opensearch-project/OpenSearch/pull/${{ env.PR_NUMBER }}." >> ./ci/documentation/issue.md
+          
+      - name: Create Issue From File
+        id: create-issue
+        uses: peter-evans/create-issue-from-file@v4
+        with:
+          title: Add documentation related to new feature
+          content-filepath: ./ci/documentation/issue.md
+          labels: documentation
+          repository: opensearch-project/documentation-website
+          token: ${{ steps.github_app_token.outputs.token }}
+      
+      - name: Print Issue
+        run: echo Created related documentation issue ${{ steps.create-issue.outputs.issue-number }}
diff --git a/.github/workflows/delete_backport_branch.yml b/.github/workflows/delete_backport_branch.yml
index d654df6b40257..387a124b8cb6a 100644
--- a/.github/workflows/delete_backport_branch.yml
+++ b/.github/workflows/delete_backport_branch.yml
@@ -12,4 +12,4 @@ jobs:
       - name: Delete merged branch
         uses: SvanBoxel/delete-merged-branch@main
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
\ No newline at end of file
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/dependabot_pr.yml b/.github/workflows/dependabot_pr.yml
index 2ac904bf4ccf7..add38e306e60b 100644
--- a/.github/workflows/dependabot_pr.yml
+++ b/.github/workflows/dependabot_pr.yml
@@ -11,14 +11,14 @@ jobs:
     steps:
       - name: GitHub App token
         id: github_app_token
-        uses: tibdex/github-app-token@v1.5.0
+        uses: tibdex/github-app-token@v2.1.0
         with:
           app_id: ${{ secrets.APP_ID }}
           private_key: ${{ secrets.APP_PRIVATE_KEY }}
           installation_id: 22958780
 
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           token: ${{ steps.github_app_token.outputs.token }}
 
@@ -47,3 +47,17 @@ jobs:
           commit_user_name: dependabot[bot]
           commit_user_email: support@github.com
           commit_options: '--signoff'
+
+      - name: Update the changelog
+        uses: dangoslen/dependabot-changelog-helper@v1
+        with:
+          version: 'Unreleased'
+
+      - name: Commit the changes
+        uses: stefanzweifel/git-auto-commit-action@v4
+        with:
+          commit_message: "Update changelog"
+          branch: ${{ github.head_ref }}
+          commit_user_name: dependabot[bot]
+          commit_user_email: support@github.com
+          commit_options: '--signoff'
diff --git a/.github/workflows/gradle-check.yml b/.github/workflows/gradle-check.yml
new file mode 100644
index 0000000000000..2d4e86a7a3522
--- /dev/null
+++ b/.github/workflows/gradle-check.yml
@@ -0,0 +1,137 @@
+name: Gradle Check (Jenkins)
+on:
+  push:
+    branches-ignore:
+      - 'backport/**'
+      - 'create-pull-request/**'
+      - 'dependabot/**'
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
+jobs:
+  gradle-check:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    permissions:
+      contents: read # to fetch code (actions/checkout)
+      pull-requests: write # to create or update comment (peter-evans/create-or-update-comment)
+      issues: write # To create an issue if check fails on push.
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 130
+    steps:
+      - name: Checkout OpenSearch repo
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Setup environment variables (PR)
+        if: github.event_name == 'pull_request_target'
+        run: |
+            echo "pr_from_sha=$(jq --raw-output .pull_request.head.sha $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+            echo "pr_from_clone_url=$(jq --raw-output .pull_request.head.repo.clone_url $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+            echo "pr_to_clone_url=$(jq --raw-output .pull_request.base.repo.clone_url $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+            echo "pr_title=$(jq --raw-output .pull_request.title $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+            echo "pr_number=$(jq --raw-output .pull_request.number $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+
+      - name: Setup environment variables (Push)
+        if: github.event_name == 'push'
+        run: |
+            repo_url="https://github.com/opensearch-project/OpenSearch"
+            ref_id=$(git rev-parse HEAD)
+            branch_name=$(git rev-parse --abbrev-ref HEAD)
+            echo "branch_name=$branch_name" >> $GITHUB_ENV
+            echo "pr_from_sha=$ref_id" >> $GITHUB_ENV
+            echo "pr_from_clone_url=$repo_url" >> $GITHUB_ENV
+            echo "pr_to_clone_url=$repo_url" >> $GITHUB_ENV
+            echo "pr_title=Push trigger $branch_name $ref_id $repo_url" >> $GITHUB_ENV
+            echo "pr_number=Null" >> $GITHUB_ENV
+
+      - name: Checkout opensearch-build repo
+        uses: actions/checkout@v4
+        with:
+          repository: opensearch-project/opensearch-build
+          ref: main
+          path: opensearch-build
+
+      - name: Trigger jenkins workflow to run gradle check
+        run: |
+            set -e
+            set -o pipefail
+            bash opensearch-build/scripts/gradle/gradle-check.sh ${{ secrets.JENKINS_GRADLE_CHECK_GENERIC_WEBHOOK_TOKEN }} | tee -a gradle-check.log
+
+      - name: Setup Result Status
+        if: always()
+        run: |
+            WORKFLOW_URL=`cat gradle-check.log | grep 'WORKFLOW_URL' | awk '{print $2}'`
+            RESULT=`cat gradle-check.log | grep 'Result:' | awk '{print $2}'`
+            echo "workflow_url=$WORKFLOW_URL" >> $GITHUB_ENV
+            echo "result=$RESULT" >> $GITHUB_ENV
+
+      - name: Upload Coverage Report
+        if: success()
+        uses: codecov/codecov-action@v3
+        with:
+          files: ./codeCoverage.xml
+
+      - name: Create Comment Success
+        if: ${{ github.event_name == 'pull_request_target' && success() && env.result == 'SUCCESS' }}
+        uses: peter-evans/create-or-update-comment@v3
+        with:
+          issue-number: ${{ env.pr_number }}
+          body: |
+              ### Gradle Check (Jenkins) Run Completed with:
+              * **RESULT:** ${{ env.result }} :white_check_mark:
+              * **URL:** ${{ env.workflow_url }}
+              * **CommitID:** ${{ env.pr_from_sha }}
+
+      - name: Extract Test Failure
+        if: ${{ github.event_name == 'pull_request_target' && env.result != 'SUCCESS' }}
+        run: |
+            TEST_FAILURES=`curl -s "${{ env.workflow_url }}/testReport/api/json?tree=suites\[cases\[status,className,name\]\]" | jq -r '.. | objects | select(.status=="FAILED",.status=="REGRESSION") | (.className + "." +  .name)' | uniq -c | sort -n -r | head -n 10`
+            if [[ "$TEST_FAILURES" != "" ]]
+            then
+              echo "test_failures<<EOF" >> $GITHUB_ENV
+              echo "" >> $GITHUB_ENV
+              echo "* **TEST FAILURES:**" >> $GITHUB_ENV
+              echo '```' >> $GITHUB_ENV
+              echo "$TEST_FAILURES" >> $GITHUB_ENV
+              echo '```' >> $GITHUB_ENV
+              echo "EOF" >> $GITHUB_ENV
+            fi
+
+      - name: Create Comment Flaky
+        if: ${{ github.event_name == 'pull_request_target' && success() && env.result != 'SUCCESS' }}
+        uses: peter-evans/create-or-update-comment@v3
+        with:
+          issue-number: ${{ env.pr_number }}
+          body: |
+            ### Gradle Check (Jenkins) Run Completed with:
+            * **RESULT:** ${{ env.result }} :grey_exclamation: ${{ env.test_failures }}
+            * **URL:** ${{ env.workflow_url }}
+            * **CommitID:** ${{ env.pr_from_sha }}
+            Please review all [flaky tests](https://github.com/opensearch-project/OpenSearch/blob/main/DEVELOPER_GUIDE.md#flaky-tests) that succeeded after retry and create an issue if one does not already exist to track the flaky failure.
+
+      - name: Create Comment Failure
+        if: ${{ github.event_name == 'pull_request_target' && failure() }}
+        uses: peter-evans/create-or-update-comment@v3
+        with:
+          issue-number: ${{ env.pr_number }}
+          body: |
+              ### Gradle Check (Jenkins) Run Completed with:
+              * **RESULT:** ${{ env.result }} :x: ${{ env.test_failures }}
+              * **URL:** ${{ env.workflow_url }}
+              * **CommitID:** ${{ env.pr_from_sha }}
+              Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
+              Is the failure [a flaky test](https://github.com/opensearch-project/OpenSearch/blob/main/DEVELOPER_GUIDE.md#flaky-tests) unrelated to your change?
+
+      - name: Create Issue On Push Failure
+        if: ${{ github.event_name == 'push' && failure() }}
+        uses: dblock/create-a-github-issue@v3
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          assignees: ${{ github.event.head_commit.author.username }}, ${{ github.triggering_actor }}
+          filename: .github/ISSUE_TEMPLATE/failed_check.md
diff --git a/.github/workflows/links.yml b/.github/workflows/links.yml
index 21fb7ab9086ee..ca026f530b4af 100644
--- a/.github/workflows/links.yml
+++ b/.github/workflows/links.yml
@@ -2,18 +2,20 @@ name: Link Checker
 on:
   schedule:
     - cron:  '0 0 * * *'
+permissions:
+  contents: read # to fetch code (actions/checkout)
 jobs:
   linkchecker:
     if: github.repository == 'opensearch-project/OpenSearch'
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: lychee Link Checker
         id: lychee
-        uses: lycheeverse/lychee-action@v1.2.0
+        uses: lycheeverse/lychee-action@v1.8.0
         with:
           args: --accept=200,403,429 --exclude-mail **/*.html **/*.md **/*.txt **/*.json --exclude-file .lychee.excludes
           fail: true
         env:
-          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
\ No newline at end of file
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
diff --git a/.github/workflows/lucene-snapshots.yml b/.github/workflows/lucene-snapshots.yml
new file mode 100644
index 0000000000000..76981276fe085
--- /dev/null
+++ b/.github/workflows/lucene-snapshots.yml
@@ -0,0 +1,60 @@
+# This workflow will check out, build, and publish snapshots of lucene.
+
+name: OpenSearch Lucene snapshots
+
+on:
+  workflow_dispatch:
+    # Inputs the workflow accepts.
+    inputs:
+      ref:
+        description:
+        required: false
+        default: 'main'
+
+jobs:
+  publish-snapshots:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    runs-on: ubuntu-latest
+    # These permissions are needed to interact with GitHub's OIDC Token endpoint.
+    permissions:
+      id-token: write
+      contents: read
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'adopt'
+
+      - name: Checkout Lucene
+        uses: actions/checkout@v4
+        with:
+          repository: 'apache/lucene'
+          path: lucene
+          ref: ${{ github.event.inputs.ref }}
+
+      - name: Set hash
+        working-directory: ./lucene
+        run: |
+          echo "REVISION=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT
+        id: version
+
+      - name: Initialize gradle settings
+        working-directory: ./lucene
+        run: ./gradlew localSettings
+
+      - name: Publish Lucene to local maven repo.
+        working-directory: ./lucene
+        run: ./gradlew publishJarsPublicationToMavenLocal -Pversion.suffix=snapshot-${{ steps.version.outputs.REVISION }}
+
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v2
+        with:
+          role-to-assume: ${{ secrets.LUCENE_SNAPSHOTS_ROLE }}
+          aws-region: us-west-2
+
+      - name: Copy files to S3 with the aws CLI.
+        run: |
+          aws s3 cp ~/.m2/repository/org/apache/lucene/ s3://${{ secrets.LUCENE_SNAPSHOTS_BUCKET }}/snapshots/lucene/org/apache/lucene/  --recursive --no-progress
diff --git a/.github/workflows/precommit.yml b/.github/workflows/precommit.yml
index 9860be4159b83..f4622859916c7 100644
--- a/.github/workflows/precommit.yml
+++ b/.github/workflows/precommit.yml
@@ -1,16 +1,30 @@
-name: Gradle Precommit
+name: Gradle Precommit and Assemble
 on: [pull_request]
 
 jobs:
   precommit:
-    runs-on: ubuntu-latest
+    if: github.repository == 'opensearch-project/OpenSearch'
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up JDK 11
-        uses: actions/setup-java@v2
+        uses: actions/setup-java@v3
         with:
           java-version: 11
-          distribution: adopt
-      - name: Run Gradle
+          distribution: temurin
+          cache: gradle
+      - name: Run Gradle (precommit)
         run: |
-          ./gradlew precommit --parallel
+          ./gradlew javadoc precommit --parallel
+      - name: Setup docker (missing on MacOS)
+        if: runner.os == 'macos'
+        run: |
+          brew install docker
+          colima start
+          sudo ln -sf $HOME/.colima/default/docker.sock /var/run/docker.sock
+      - name: Run Gradle (assemble)
+        run: |
+          ./gradlew assemble --parallel
diff --git a/.github/workflows/publish-maven-snapshots.yml b/.github/workflows/publish-maven-snapshots.yml
new file mode 100644
index 0000000000000..8c08df269a999
--- /dev/null
+++ b/.github/workflows/publish-maven-snapshots.yml
@@ -0,0 +1,40 @@
+name: Publish snapshots to maven
+
+on:
+  workflow_dispatch:
+  push:
+      branches:
+        - main
+        - '[0-9]+.[0-9]+'
+        - '[0-9]+.x'
+
+jobs:
+  build-and-publish-snapshots:
+    if: github.repository == 'opensearch-project/OpenSearch'
+    runs-on: ubuntu-latest
+
+    permissions:
+      id-token: write
+      contents: write
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          distribution: adopt
+          java-version: 17
+
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v2
+        with:
+          role-to-assume: ${{ secrets.PUBLISH_SNAPSHOTS_ROLE }}
+          aws-region: us-east-1
+
+      - name: Publish snapshots to maven
+        run: |
+          export SONATYPE_USERNAME=$(aws secretsmanager get-secret-value --secret-id maven-snapshots-username --query SecretString --output text)
+          export SONATYPE_PASSWORD=$(aws secretsmanager get-secret-value --secret-id maven-snapshots-password --query SecretString --output text)
+          echo "::add-mask::$SONATYPE_USERNAME"
+          echo "::add-mask::$SONATYPE_PASSWORD"
+          ./gradlew publishNebulaPublicationToSnapshotsRepository
diff --git a/.github/workflows/version.yml b/.github/workflows/version.yml
index b42e7c4f2f317..a20c671c137b2 100644
--- a/.github/workflows/version.yml
+++ b/.github/workflows/version.yml
@@ -5,19 +5,21 @@ on:
     tags:
       - '*.*.*'
 
-jobs:  
+permissions: {}
+jobs:
   build:
+    if: github.repository == 'opensearch-project/OpenSearch'
     runs-on: ubuntu-latest
     steps:
       - name: GitHub App token
         id: github_app_token
-        uses: tibdex/github-app-token@v1.5.0
+        uses: tibdex/github-app-token@v2.1.0
         with:
           app_id: ${{ secrets.APP_ID }}
           private_key: ${{ secrets.APP_PRIVATE_KEY }}
           installation_id: 22958780
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Fetch Tag and Version Information
         run: |
           TAG=$(echo "${GITHUB_REF#refs/*/}")
@@ -29,7 +31,11 @@ jobs:
           CURRENT_VERSION_ARRAY[2]=$((CURRENT_VERSION_ARRAY[2]+1))
           NEXT_VERSION=$(IFS=. ; echo "${CURRENT_VERSION_ARRAY[*]:0:3}")
           NEXT_VERSION_UNDERSCORE=$(IFS=_ ; echo "V_${CURRENT_VERSION_ARRAY[*]:0:3}")
-          NEXT_VERSION_ID=$(IFS=0 ; echo "${CURRENT_VERSION_ARRAY[*]:0:3}99")
+          if [[ ${#CURRENT_VERSION_ARRAY[2]} -gt 1 ]]; then
+            NEXT_VERSION_ID="${CURRENT_VERSION_ARRAY[0]:0:3}0${CURRENT_VERSION_ARRAY[1]:0:3}${CURRENT_VERSION_ARRAY[2]:0:3}99"
+          else
+            NEXT_VERSION_ID=$(IFS=0 ; echo "${CURRENT_VERSION_ARRAY[*]:0:3}99")
+          fi
           echo "TAG=$TAG" >> $GITHUB_ENV
           echo "BASE=$BASE" >> $GITHUB_ENV
           echo "BASE_X=$BASE_X" >> $GITHUB_ENV
@@ -38,7 +44,7 @@ jobs:
           echo "NEXT_VERSION=$NEXT_VERSION" >> $GITHUB_ENV
           echo "NEXT_VERSION_UNDERSCORE=$NEXT_VERSION_UNDERSCORE" >> $GITHUB_ENV
           echo "NEXT_VERSION_ID=$NEXT_VERSION_ID" >> $GITHUB_ENV
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           ref: ${{ env.BASE }}
           token: ${{ steps.github_app_token.outputs.token }}
@@ -49,22 +55,25 @@ jobs:
           echo "  - \"$CURRENT_VERSION\"" >> .ci/bwcVersions
           sed -i "s/opensearch        = $CURRENT_VERSION/opensearch        = $NEXT_VERSION/g" buildSrc/version.properties
           echo Adding $NEXT_VERSION_UNDERSCORE after $CURRENT_VERSION_UNDERSCORE
-          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" server/src/main/java/org/opensearch/Version.java
-          sed -i "s/CURRENT = $CURRENT_VERSION_UNDERSCORE;/CURRENT = $NEXT_VERSION_UNDERSCORE;/g" server/src/main/java/org/opensearch/Version.java
+          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" libs/core/src/main/java/org/opensearch/Version.java
+          sed -i "s/CURRENT = $CURRENT_VERSION_UNDERSCORE;/CURRENT = $NEXT_VERSION_UNDERSCORE;/g" libs/core/src/main/java/org/opensearch/Version.java
 
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v3
+        uses: peter-evans/create-pull-request@v5
         with:
           token: ${{ steps.github_app_token.outputs.token }}
           base: ${{ env.BASE }}
           branch: 'create-pull-request/patch-${{ env.BASE }}'
-          commit-message: Incremented version to ${{ env.NEXT_VERSION }}
+          commit-message: Increment version to ${{ env.NEXT_VERSION }}
+          signoff: true
           delete-branch: true
-          title: '[AUTO] Incremented version to ${{ env.NEXT_VERSION }}.'
+          labels: |
+            autocut
+          title: '[AUTO] Increment version to ${{ env.NEXT_VERSION }}.'
           body: |
             I've noticed that a new tag ${{ env.TAG }} was pushed, and incremented the version from ${{ env.CURRENT_VERSION }} to ${{ env.NEXT_VERSION }}.
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           ref: ${{ env.BASE_X }}
           token: ${{ steps.github_app_token.outputs.token }}
@@ -74,21 +83,24 @@ jobs:
           echo Adding bwc version $NEXT_VERSION after $CURRENT_VERSION
           sed -i "s/- \"$CURRENT_VERSION\"/\0\n  - \"$NEXT_VERSION\"/g" .ci/bwcVersions
           echo Adding $NEXT_VERSION_UNDERSCORE after $CURRENT_VERSION_UNDERSCORE
-          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" server/src/main/java/org/opensearch/Version.java
+          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" libs/core/src/main/java/org/opensearch/Version.java
 
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v3
+        uses: peter-evans/create-pull-request@v5
         with:
           token: ${{ steps.github_app_token.outputs.token }}
           base: ${{ env.BASE_X }}
           branch: 'create-pull-request/patch-${{ env.BASE_X }}'
-          commit-message: Added bwc version ${{ env.NEXT_VERSION }}
+          commit-message: Add bwc version ${{ env.NEXT_VERSION }}
+          signoff: true
           delete-branch: true
-          title: '[AUTO] [${{ env.BASE_X }}] Added bwc version ${{ env.NEXT_VERSION }}.'
+          labels: |
+            autocut
+          title: '[AUTO] [${{ env.BASE_X }}] Add bwc version ${{ env.NEXT_VERSION }}.'
           body: |
             I've noticed that a new tag ${{ env.TAG }} was pushed, and added a bwc version ${{ env.NEXT_VERSION }}.
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           ref: main
           token: ${{ steps.github_app_token.outputs.token }}
@@ -98,16 +110,19 @@ jobs:
           echo Adding bwc version $NEXT_VERSION after $CURRENT_VERSION
           sed -i "s/- \"$CURRENT_VERSION\"/\0\n  - \"$NEXT_VERSION\"/g" .ci/bwcVersions
           echo Adding $NEXT_VERSION_UNDERSCORE after $CURRENT_VERSION_UNDERSCORE
-          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" server/src/main/java/org/opensearch/Version.java
+          sed -i "s/public static final Version $CURRENT_VERSION_UNDERSCORE = new Version(\([[:digit:]]\+\)\(.*\));/\0\n    public static final Version $NEXT_VERSION_UNDERSCORE = new Version($NEXT_VERSION_ID\2);/g" libs/core/src/main/java/org/opensearch/Version.java
 
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v3
+        uses: peter-evans/create-pull-request@v5
         with:
           token: ${{ steps.github_app_token.outputs.token }}
           base: main
           branch: 'create-pull-request/patch-main'
-          commit-message: Added bwc version ${{ env.NEXT_VERSION }}
+          commit-message: Add bwc version ${{ env.NEXT_VERSION }}
+          signoff: true
           delete-branch: true
-          title: '[AUTO] [main] Added bwc version ${{ env.NEXT_VERSION }}.'
+          labels: |
+            autocut
+          title: '[AUTO] [main] Add bwc version ${{ env.NEXT_VERSION }}.'
           body: |
             I've noticed that a new tag ${{ env.TAG }} was pushed, and added a bwc version ${{ env.NEXT_VERSION }}.
diff --git a/.github/workflows/wrapper.yml b/.github/workflows/wrapper.yml
index d577699b66dc0..6dd48ca15eaa9 100644
--- a/.github/workflows/wrapper.yml
+++ b/.github/workflows/wrapper.yml
@@ -1,10 +1,11 @@
 name: Validate Gradle Wrapper
-on: [push, pull_request]
+on: [pull_request]
 
 jobs:
   validate:
     name: Validate
+    if: github.repository == 'opensearch-project/OpenSearch'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: gradle/wrapper-validation-action@v1
\ No newline at end of file
+      - uses: actions/checkout@v4
+      - uses: gradle/wrapper-validation-action@v1
diff --git a/.gitignore b/.gitignore
index e2cb6d8d37a82..82914fb4fc1e7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,8 +12,13 @@ out/
 !.idea/runConfigurations/Debug_OpenSearch.xml
 !.idea/vcs.xml
 
-# These files are generated in the main tree by IntelliJ
+# These files are generated in the main tree by annotation processors
 benchmarks/src/main/generated/*
+benchmarks/bin/*
+benchmarks/build-eclipse-default/*
+server/bin/*
+server/build-eclipse-default/*
+test/framework/build-eclipse-default/*
 
 # eclipse files
 .project
@@ -56,3 +61,6 @@ testfixtures_shared/
 
 # These are generated from .ci/jobs.t
 .ci/jobs/
+
+# build files generated
+doc-tools/missing-doclet/bin/
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
index 5cf789707c58c..f090532aecfc2 100644
--- a/.idea/inspectionProfiles/Project_Default.xml
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -2,8 +2,11 @@
   <profile version="1.0">
     <option name="myName" value="Project Default" />
     <inspection_tool class="GroovyPointlessBoolean" enabled="false" level="WARNING" enabled_by_default="false" />
+    <inspection_tool class="JavadocDeclaration" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ADDITIONAL_TAGS" value="opensearch.experimental,opensearch.internal,opensearch.api" />
+    </inspection_tool>
     <inspection_tool class="PointlessBooleanExpression" enabled="false" level="WARNING" enabled_by_default="false">
       <option name="m_ignoreExpressionsContainingConstants" value="true" />
     </inspection_tool>
   </profile>
-</component>
\ No newline at end of file
+</component>
diff --git a/.whitesource b/.whitesource
deleted file mode 100644
index 81bf84f97dd66..0000000000000
--- a/.whitesource
+++ /dev/null
@@ -1,15 +0,0 @@
-{
-  "scanSettings": {
-    "configMode": "LOCAL",
-    "configExternalURL": "",
-    "projectToken": "",
-    "baseBranches": ["1.x"]
-  },
-  "checkRunSettings": {
-    "vulnerableCheckRunConclusionLevel": "failure",
-    "displayMode": "diff"
-  },
-  "issueSettings": {
-    "minSeverityLevel": "LOW"
-  }
-}
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000000000..89b3bdce85ed8
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,70 @@
+# CHANGELOG
+All notable changes to this project are documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). See the [CONTRIBUTING guide](./CONTRIBUTING.md#Changelog) for instructions on how to add changelog entries.
+
+## [Unreleased 2.x]
+### Added
+- Add coordinator level stats for search latency ([#8386](https://github.com/opensearch-project/OpenSearch/issues/8386))
+- Add metrics for thread_pool task wait time ([#9681](https://github.com/opensearch-project/OpenSearch/pull/9681))
+- Async blob read support for S3 plugin ([#9694](https://github.com/opensearch-project/OpenSearch/pull/9694))
+- [Telemetry-Otel] Added support for OtlpGrpcSpanExporter exporter ([#9666](https://github.com/opensearch-project/OpenSearch/pull/9666))
+- Async blob read support for encrypted containers ([#10131](https://github.com/opensearch-project/OpenSearch/pull/10131))
+- Implement Visitor Design pattern in QueryBuilder to enable the capability to traverse through the complex QueryBuilder tree. ([#10110](https://github.com/opensearch-project/OpenSearch/pull/10110))
+- Add capability to restrict async durability mode for remote indexes ([#10189](https://github.com/opensearch-project/OpenSearch/pull/10189))
+- Add Doc Status Counter for Indexing Engine ([#4562](https://github.com/opensearch-project/OpenSearch/issues/4562))
+- Add unreferenced file cleanup count to merge stats ([#10204](https://github.com/opensearch-project/OpenSearch/pull/10204))
+- Configurable merge policy for index with an option to choose from LogByteSize and Tiered merge policy ([#9992](https://github.com/opensearch-project/OpenSearch/pull/9992))
+- [Remote Store] Add support to restrict creation & deletion if system repository and mutation of immutable settings of system repository ([#9839](https://github.com/opensearch-project/OpenSearch/pull/9839))
+### Dependencies
+- Bump JNA version from 5.5 to 5.13 ([#9963](https://github.com/opensearch-project/OpenSearch/pull/9963))
+- Bump `peter-evans/create-or-update-comment` from 2 to 3 ([#9575](https://github.com/opensearch-project/OpenSearch/pull/9575))
+- Bump `actions/checkout` from 2 to 4 ([#9968](https://github.com/opensearch-project/OpenSearch/pull/9968))
+- Bump OpenTelemetry from 1.26.0 to 1.30.1 ([#9950](https://github.com/opensearch-project/OpenSearch/pull/9950))
+- Bump `org.apache.commons:commons-compress` from 1.23.0 to 1.24.0 ([#9973, #9972](https://github.com/opensearch-project/OpenSearch/pull/9973, https://github.com/opensearch-project/OpenSearch/pull/9972))
+- Bump `com.google.cloud:google-cloud-core-http` from 2.21.1 to 2.23.0 ([#9971](https://github.com/opensearch-project/OpenSearch/pull/9971))
+- Bump `mockito` from 5.4.0 to 5.5.0 ([#10022](https://github.com/opensearch-project/OpenSearch/pull/10022))
+- Bump `bytebuddy` from 1.14.3 to 1.14.7 ([#10022](https://github.com/opensearch-project/OpenSearch/pull/10022))
+- Bump `com.zaxxer:SparseBitSet` from 1.2 to 1.3 ([#10098](https://github.com/opensearch-project/OpenSearch/pull/10098))
+- Bump `tibdex/github-app-token` from 1.5.0 to 2.1.0 ([#10125](https://github.com/opensearch-project/OpenSearch/pull/10125))
+- Bump `org.wiremock:wiremock-standalone` from 2.35.0 to 3.1.0 ([#9752](https://github.com/opensearch-project/OpenSearch/pull/9752))
+- Bump `org.eclipse.jgit` from 6.5.0 to 6.7.0 ([#10147](https://github.com/opensearch-project/OpenSearch/pull/10147))
+- Bump `codecov/codecov-action` from 2 to 3 ([#10209](https://github.com/opensearch-project/OpenSearch/pull/10209))
+- Bump `com.google.http-client:google-http-client-jackson2` from 1.43.2 to 1.43.3 ([#10126](https://github.com/opensearch-project/OpenSearch/pull/10126))
+- Bump `org.xerial.snappy:snappy-java` from 1.1.10.3 to 1.1.10.5 ([#10206](https://github.com/opensearch-project/OpenSearch/pull/10206), [#10299](https://github.com/opensearch-project/OpenSearch/pull/10299))
+- Bump `org.bouncycastle:bcpkix-jdk15to18` from 1.75 to 1.76 ([10219](https://github.com/opensearch-project/OpenSearch/pull/10219))`
+- Bump `org.bouncycastle:bcprov-jdk15to18` from 1.75 to 1.76 ([10219](https://github.com/opensearch-project/OpenSearch/pull/10219))`
+- Bump `org.bouncycastle:bcmail-jdk15to18` from 1.75 to 1.76 ([10219](https://github.com/opensearch-project/OpenSearch/pull/10219))`
+- Bump asm from 9.5 to 9.6 ([#10302](https://github.com/opensearch-project/OpenSearch/pull/10302))
+- Bump netty from 4.1.97.Final to 4.1.99.Final ([#10303](https://github.com/opensearch-project/OpenSearch/pull/10303))
+- Bump `peter-evans/create-pull-request` from 3 to 5 ([#10301](https://github.com/opensearch-project/OpenSearch/pull/10301))
+
+### Changed
+- Add instrumentation in rest and network layer. ([#9415](https://github.com/opensearch-project/OpenSearch/pull/9415))
+- Allow parameterization of tests with OpenSearchIntegTestCase.SuiteScopeTestCase annotation ([#9916](https://github.com/opensearch-project/OpenSearch/pull/9916))
+- Force merge with `only_expunge_deletes` honors max segment size ([#10036](https://github.com/opensearch-project/OpenSearch/pull/10036))
+- Add instrumentation in transport service. ([#10042](https://github.com/opensearch-project/OpenSearch/pull/10042))
+- [Tracing Framework] Add support for SpanKind. ([#10122](https://github.com/opensearch-project/OpenSearch/pull/10122))
+- Pass parent filter to inner query in nested query ([#10246](https://github.com/opensearch-project/OpenSearch/pull/10246))
+- Disable concurrent segment search when terminate_after is used ([#10200](https://github.com/opensearch-project/OpenSearch/pull/10200))
+- Add instrumentation in Inbound Handler. ([#100143](https://github.com/opensearch-project/OpenSearch/pull/10143))
+- Enable remote segment upload backpressure by default ([#10356](https://github.com/opensearch-project/OpenSearch/pull/10356))
+- [Remote Store] Add support to reload repository metadata inplace ([#9569](https://github.com/opensearch-project/OpenSearch/pull/9569))
+- [Metrics Framework] Add Metrics framework. ([#10241](https://github.com/opensearch-project/OpenSearch/pull/10241))
+
+### Deprecated
+
+### Removed
+- Remove spurious SGID bit on directories ([#9447](https://github.com/opensearch-project/OpenSearch/pull/9447))
+
+### Fixed
+- Fix ignore_missing parameter has no effect when using template snippet in rename ingest processor ([#9725](https://github.com/opensearch-project/OpenSearch/pull/9725))
+- Fix broken backward compatibility from 2.7 for IndexSorted field indices ([#10045](https://github.com/opensearch-project/OpenSearch/pull/10045))
+- Fix concurrent search NPE when track_total_hits, terminate_after and size=0 are used ([#10082](https://github.com/opensearch-project/OpenSearch/pull/10082))
+- Fix remove ingest processor handing ignore_missing parameter not correctly ([10089](https://github.com/opensearch-project/OpenSearch/pull/10089))
+- Fix registration and initialization of multiple extensions ([10256](https://github.com/opensearch-project/OpenSearch/pull/10256))
+- Fix circular dependency in Settings initialization ([10194](https://github.com/opensearch-project/OpenSearch/pull/10194))
+
+### Security
+
+[Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.11...2.x
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9a68cde006a6f..d379d78829318 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -6,6 +6,7 @@
     - [Documentation Changes](#documentation-changes)
     - [Contributing Code](#contributing-code)
   - [Developer Certificate of Origin](#developer-certificate-of-origin)
+  - [Changelog](#changelog)
   - [Review Process](#review-process)
 
 # Contributing to OpenSearch
@@ -59,6 +60,16 @@ If you would like to contribute to the documentation, please do so in the [docum
 
 As with other types of contributions, the first step is to [**open an issue on GitHub**](https://github.com/opensearch-project/OpenSearch/issues/new/choose). Opening an issue before you make changes makes sure that someone else isn't already working on that particular problem. It also lets us all work together to find the right approach before you spend a bunch of time on a PR. So again, when in doubt, open an issue.
 
+Additionally, here are a few guidelines to help you decide whether a particular feature should be included in OpenSearch.
+
+**Is your feature important to most users of OpenSearch?**
+
+If you believe that a feature is going to fulfill a need for most users of OpenSearch, then it belongs in OpenSearch. However, we don't want every feature built into the core server. If the feature requires additional permissions or brings in extra dependencies it should instead be included as a module in core.
+
+**Is your feature a common dependency across multiple plugins?**
+
+Does this feature contain functionality that cuts across multiple plugins? If so, this most likely belongs in OpenSearch as a core module or plugin.
+
 Once you've opened an issue, check out our [Developer Guide](./DEVELOPER_GUIDE.md) for instructions on how to get started.
 
 ## Developer Certificate of Origin
@@ -106,6 +117,42 @@ Signed-off-by: Jane Smith <jane.smith@email.com>
 ```
 You may type this line on your own when writing your commit messages. However, if your user.name and user.email are set in your git configs, you can use `-s` or `--signoff` to add the `Signed-off-by` line to the end of the commit message.
 
+## Changelog
+
+OpenSearch maintains version specific changelog by enforcing a change to the ongoing [CHANGELOG](CHANGELOG.md) file adhering to the [Keep A Changelog](https://keepachangelog.com/en/1.0.0/) format. The purpose of the changelog is for the contributors and maintainers to incrementally build the release notes throughout the development process to avoid a painful and error-prone process of attempting to compile the release notes at release time. On each release the "unreleased" entries of the changelog are moved to the appropriate release notes document in the `./release-notes` folder. Also, incrementally building the changelog provides a concise, human-readable list of significant features that have been added to the unreleased version under development.
+
+### Which changes require a CHANGELOG entry?
+Changelogs are intended for operators/administrators, developers integrating with libraries and APIs, and end-users interacting with OpenSearch Dashboards and/or the REST API (collectively referred to as "user"). In short, any change that a user of OpenSearch might want to be aware of should be included in the changelog. The changelog is _not_ intended to replace the git commit log that developers of OpenSearch itself rely upon. The following are some examples of changes that should be in the changelog:
+
+- A newly added feature
+- A fix for a user-facing bug
+- Dependency updates
+- Fixes for security issues
+
+The following are some examples where a changelog entry is not necessary:
+
+- Adding, modifying, or fixing tests
+- An incremental PR for a larger feature (such features should include _one_ changelog entry for the feature)
+- Documentation changes or code refactoring
+- Build-related changes
+
+Any PR that does not include a changelog entry will result in a failure of the validation workflow in GitHub. If the contributor and maintainers agree that no changelog entry is required, then the `skip-changelog` label can be applied to the PR which will result in the workflow passing.
+
+### How to add my changes to [CHANGELOG](CHANGELOG.md)?
+
+Adding in the change is two step process:
+1. Add your changes to the corresponding section within the CHANGELOG file with dummy pull request information, publish the PR
+2. Update the entry for your change in [`CHANGELOG.md`](CHANGELOG.md) and make sure that you reference the pull request there.
+
+### Where should I put my CHANGELOG entry?
+Please review the [branching strategy](https://github.com/opensearch-project/.github/blob/main/RELEASING.md#opensearch-branching) document. The changelog on the `main` branch will contain sections for the _next major_ and _next minor_ releases. Your entry should go into the section it is intended to be released in. In practice, most changes to `main` will be backported to the next minor release so most entries will likely be in that section.
+
+The following examples assume the _next major_ release on main is 3.0, then _next minor_ release is 2.5, and the _current_ release is 2.4.
+
+- **Add a new feature to release in next minor:** Add a changelog entry to `[Unreleased 2.x]` on main, then backport to 2.x (including the changelog entry).
+- **Introduce a breaking API change to release in next major:** Add a changelog entry to `[Unreleased 3.0]` on main, do not backport.
+- **Upgrade a dependency to fix a CVE:** Add a changelog entry to `[Unreleased 2.x]` on main, then backport to 2.x (including the changelog entry), then backport to 2.4 and ensure the changelog entry is added to `[Unreleased 2.4.1]`.
+
 ## Review Process
 
 We deeply appreciate everyone who takes the time to make a contribution. We will review all contributions as quickly as possible. As a reminder, [opening an issue](https://github.com/opensearch-project/OpenSearch/issues/new/choose) discussing your change before you make it is the best way to smooth the PR process. This will prevent a rejection because someone else is already working on the problem, or because the solution is incompatible with the architectural direction.
diff --git a/DEVELOPER_GUIDE.md b/DEVELOPER_GUIDE.md
index 9b1bc933eb1e3..778fe2d4bc5f5 100644
--- a/DEVELOPER_GUIDE.md
+++ b/DEVELOPER_GUIDE.md
@@ -4,14 +4,17 @@
     - [Install Prerequisites](#install-prerequisites)
       - [JDK 11](#jdk-11)
       - [JDK 14](#jdk-14)
-      - [Runtime JDK](#runtime-jdk)
+      - [JDK 17](#jdk-17)
+      - [Custom Runtime JDK](#custom-runtime-jdk)
       - [Windows](#windows)
       - [Docker](#docker)
     - [Build](#build)
+      - [Generated Code](#generated-code)
     - [Run Tests](#run-tests)
     - [Run OpenSearch](#run-opensearch)
   - [Use an Editor](#use-an-editor)
     - [IntelliJ IDEA](#intellij-idea)
+      - [Remote development using JetBrains Gateway](#remote-development-using-jetbrains-gateway)
     - [Visual Studio Code](#visual-studio-code)
     - [Eclipse](#eclipse)
   - [Project Layout](#project-layout)
@@ -24,6 +27,7 @@
     - [`server`](#server)
     - [`test`](#test)
   - [Java Language Formatting Guidelines](#java-language-formatting-guidelines)
+  - [Adding Dependencies](#adding-dependencies)
     - [Editor / IDE Support](#editor--ide-support)
     - [Formatting Failures](#formatting-failures)
   - [Gradle Build](#gradle-build)
@@ -35,19 +39,28 @@
       - [testImplementation](#testimplementation)
     - [Gradle Plugins](#gradle-plugins)
       - [Distribution Download Plugin](#distribution-download-plugin)
-  - [Misc](#misc)
-    - [git-secrets](#git-secrets)
-      - [Installation](#installation)
-      - [Configuration](#configuration)
+    - [Creating fat-JAR of a Module](#creating-fat-jar-of-a-module)
   - [Components](#components)
-    - [Build libraries & interfaces](#build-libraries--interfaces)
+    - [Build Libraries & Interfaces](#build-libraries--interfaces)
     - [Clients & Libraries](#clients--libraries)
     - [Plugins](#plugins-1)
-    - [Indexing & search](#indexing--search)
+    - [Indexing & Search](#indexing--search)
     - [Aggregations](#aggregations)
     - [Distributed Framework](#distributed-framework)
-  - [Submitting Changes](#submitting-changes)
-  - [Backports](#backports)
+  - [Misc](#misc)
+    - [Git Secrets](#git-secrets)
+      - [Installation](#installation)
+      - [Configuration](#configuration)
+    - [Submitting Changes](#submitting-changes)
+    - [Backwards Compatibility](#backwards-compatibility)
+      - [Data](#data)
+      - [Developer API](#developer-api)
+      - [User API](#user-api)
+      - [Experimental Development](#experimental-development)
+    - [Backports](#backports)
+    - [LineLint](#linelint)
+    - [Lucene Snapshots](#lucene-snapshots)
+    - [Flaky Tests](#flaky-tests)
 
 # Developer Guide
 
@@ -122,6 +135,17 @@ To build a distribution to run on your local platform, run:
 
 All distributions built will be under `distributions/archives`.
 
+#### Generated Code
+
+OpenSearch uses code generators like [Protobuf](https://protobuf.dev/).
+OpenSearch build system already takes a dependency of generating code from protobuf, incase you run into compilation errors, run:
+
+```
+./gradlew generateProto
+```
+
+Generated code in OpenSearch is used to establish cross version compatibility communication for API contracts within OpenSearch.
+
 ### Run Tests
 
 OpenSearch uses a Gradle wrapper for its build. Run `gradlew` on Unix systems, or `gradlew.bat` on Windows in the root of the repository.
@@ -240,7 +264,10 @@ This repository is split into many top level directories. The most important one
 
 ### `distribution`
 
-Builds our tar and zip archives and our rpm and deb packages.
+Builds our tar and zip archives and our rpm and deb packages. There are several flavors of the distributions, with the classifier included in the name of the final deliverable (archive or package):
+ - default (no classifier), the distribution with bundled JDK
+ - `-no-jdk-` - the distribution without bundled JDK/JRE, assumes the JDK/JRE is going to be pre-installed on the target systems
+ - `-jre-` - the distribution bundled with JRE (smaller footprint), supported as experimental feature for some platforms
 
 ### `libs`
 
@@ -317,6 +344,18 @@ Please follow these formatting guidelines:
 * Note that JavaDoc and block comments i.e. `/* ... */` are not formatted, but line comments i.e `// ...` are.
 * There is an implicit rule that negative boolean expressions should use the form `foo == false` instead of `!foo` for better readability of the code. While this isn't strictly enforced, if might get called out in PR reviews as something to change.
 
+## Adding Dependencies
+
+When adding a new dependency or removing an existing dependency via any `build.gradle` (that are not in the test scope), update the dependency LICENSE and library SHAs.
+
+For example, after adding `api "org.slf4j:slf4j-api:${versions.slf4j}"` to [plugins/discovery-ec2/build.gradle](plugins/discovery-ec2/build.gradle), copy the library `LICENSE.txt` and `NOTICE.txt` to `plugins/discovery-ec2/licenses/slf4j-api-LICENSE.txt` and `plugins/discovery-ec2/licenses/slf4j-api-NOTICE.txt`, then run the following to generate `plugins/discovery-ec2/licenses/slf4j-api-1.7.36.jar.sha1`.
+
+```
+./gradlew :plugins:discovery-ec2:updateSHAs
+```
+
+Ensure that `./gradlew :plugins:discovery-ec2:check` passes before submitting changes.
+
 ### Editor / IDE Support
 
 IntelliJ IDEs can [import](https://blog.jetbrains.com/idea/2014/01/intellij-idea-13-importing-code-formatter-settings-from-eclipse/) the [settings file](buildSrc/formatterConfig.xml), and / or use the [Eclipse Code Formatter](https://plugins.jetbrains.com/plugin/6546-eclipse-code-formatter)
@@ -372,38 +411,49 @@ The Distribution Download plugin downloads the latest version of OpenSearch by d
 ./gradlew integTest -PcustomDistributionUrl="https://ci.opensearch.org/ci/dbc/bundle-build/1.2.0/1127/linux/x64/dist/opensearch-1.2.0-linux-x64.tar.gz"
 ```
 
+### Creating fat-JAR of a Module
 
-## Misc
+A fat-JAR (or an uber-JAR) is the JAR, which contains classes from all the libraries, on which your project depends and, of course, the classes of current project.
 
-### git-secrets
+There might be cases where a developer would like to add some custom logic to the code of a module (or multiple modules) and generate a fat-JAR that can be directly used by the dependency management tool. For example, in [#3665](https://github.com/opensearch-project/OpenSearch/pull/3665) a developer wanted to provide a tentative patch as a fat-JAR to a consumer for changes made in the high level REST client.
 
-Security is our top priority. Avoid checking in credentials.
+Use [Gradle Shadow plugin](https://imperceptiblethoughts.com/shadow/).
+Add the following to the `build.gradle` file of the module for which you want to create the fat-JAR, e.g. `client/rest-high-level/build.gradle`:
 
-#### Installation
-Install [awslabs/git-secrets](https://github.com/awslabs/git-secrets) by running the following commands.
 ```
-git clone https://github.com/awslabs/git-secrets.git
-cd git-secrets
-make install
+apply plugin: 'com.github.johnrengelman.shadow'
 ```
 
-#### Configuration
-You can configure git secrets per repository, you need to change the directory to the root of the repository and run the following command.
+Run the `shadowJar` command using:
 ```
-git secrets --install
-✓ Installed commit-msg hook to .git/hooks/commit-msg
-✓ Installed pre-commit hook to .git/hooks/pre-commit
-✓ Installed prepare-commit-msg hook to .git/hooks/prepare-commit-msg
+./gradlew :client:rest-high-level:shadowJar
 ```
-Then, you need to apply patterns for git-secrets, you can install the AWS standard patterns by running the following command.
+
+This will generate a fat-JAR in the `build/distributions` folder of the module, e.g. .`/client/rest-high-level/build/distributions/opensearch-rest-high-level-client-1.4.0-SNAPSHOT.jar`.
+
+You can further customize your fat-JAR by customising the plugin, More information about shadow plugin can be found [here](https://imperceptiblethoughts.com/shadow/).
+
+To use the generated JAR, install the JAR locally, e.g.
 ```
-git secrets --register-aws
+mvn install:install-file -Dfile=src/main/resources/opensearch-rest-high-level-client-1.4.0-SNAPSHOT.jar -DgroupId=org.opensearch.client -DartifactId=opensearch-rest-high-level-client -Dversion=1.4.0-SNAPSHOT -Dpackaging=jar -DgeneratePom=true
+```
+
+Refer the installed JAR as any other maven artifact, e.g.
+
+```
+<dependency>
+    <groupId>org.opensearch.client</groupId>
+    <artifactId>opensearch-rest-high-level-client</artifactId>
+    <version>1.4.0-SNAPSHOT</version>
+</dependency>
 ```
 
 ## Components
+
 As you work in the OpenSearch repo you may notice issues getting labeled with component labels.  It's a housekeeping task to help group together similar pieces of work.  You can pretty much ignore it, but if you're curious, here's what the different labels mean:
 
-### Build libraries & interfaces
+### Build Libraries & Interfaces
+
 Tasks to make sure the build tasks are useful and packaging and distribution are easy.
 
 Includes:
@@ -415,8 +465,8 @@ Includes:
 - Compatibility
 - Javadoc enforcement
 
-
 ### Clients & Libraries
+
 APIs and communication mechanisms for external connections to OpenSearch.  This includes the “library” directory in OpenSearch (a set of common functions).
 
 Includes:
@@ -426,6 +476,7 @@ Includes:
 - CLI
 
 ### Plugins
+
 Anything touching the plugin infrastructure within core OpenSearch.
 
 Includes:
@@ -435,7 +486,8 @@ Includes:
 - Plugin interfaces
 
 
-### Indexing & search
+### Indexing & Search
+
 The critical path of indexing and search, including:  Measure index and search, performance, Improving the performance of indexing and search, ensure synchronization OpenSearch APIs with upstream Lucene change (e.g. new field types, changing doc values and codex).
 
 Includes:
@@ -446,6 +498,7 @@ Includes:
 - DocValues
 
 ### Aggregations
+
 Making sure OpenSearch can be used as a compute engine.
 
 Includes:
@@ -454,21 +507,134 @@ Includes:
 - Framework
 
 ### Distributed Framework
+
 Work to make sure that OpenSearch can scale in a distributed manner.
 
 Includes:
 
-- Nodes (Master, Data, Compute, Ingest, Discovery, etc.)
+- Nodes (Cluster Manager, Data, Compute, Ingest, Discovery, etc.)
 - Replication & Merge Policies (Document, Segment level)
 - Snapshot/Restore (repositories; S3, Azure, GCP, NFS)
 - Translog (e.g., OpenSearch, Kafka, Kinesis)
 - Shard Strategies
 - Circuit Breakers
 
-## Submitting Changes
+## Misc
+
+### Git Secrets
+
+Security is our top priority. Avoid checking in credentials.
+
+#### Installation
+
+Install [awslabs/git-secrets](https://github.com/awslabs/git-secrets) by running the following commands.
+```
+git clone https://github.com/awslabs/git-secrets.git
+cd git-secrets
+make install
+```
+
+#### Configuration
+
+You can configure git secrets per repository, you need to change the directory to the root of the repository and run the following command.
+```
+git secrets --install
+✓ Installed commit-msg hook to .git/hooks/commit-msg
+✓ Installed pre-commit hook to .git/hooks/pre-commit
+✓ Installed prepare-commit-msg hook to .git/hooks/prepare-commit-msg
+```
+Then, you need to apply patterns for git-secrets, you can install the AWS standard patterns by running the following command.
+```
+git secrets --register-aws
+```
+
+### Submitting Changes
 
 See [CONTRIBUTING](CONTRIBUTING.md).
 
-## Backports
+### Backwards Compatibility
+
+OpenSearch strives for a smooth and easy upgrade experience that is resilient to data loss and corruption while minimizing downtime and ensuring integration with
+external systems does not unexpectedly break.
+
+To provide these guarantees each version must be designed and developed with [forward compatibility](https://en.wikipedia.org/wiki/Forward_compatibility) in mind.
+OpenSearch addresses backward and forward compatibility at three different levels: 1. Data, 2. Developer API, 3. User API. These levels and the developer mechanisms
+to ensure backwards compatibility are provided below.
+
+#### Data
+
+The data level consists of index and application data file formats. OpenSearch guarantees file formats and indexes are compatible only back to the first release of
+the previous major version. If on disk formats or encodings need to be changed (including index data, cluster state, or any other persisted data) developers must
+use Version checks accordingly (e.g., `Version.onOrAfter`, `Version.before`) to guarantee backwards compatibility.
+
+#### Developer API
+
+The Developer API consists of interfaces and foundation software implementations that enable external users to develop new OpenSearch features. This includes obvious
+components such as the Plugin and Extension frameworks and less obvious components such as REST Action Handlers. When developing a new feature of OpenSearch it is
+important to explicitly mark which implementation components may, or may not, be extended by external implementations. For example, all new API classes with
+`@PublicApi` annotation (or documented as `@opensearch.api`) signal that the new component may be extended by an external implementation and therefore provide
+backwards compatibility guarantees. Similarly, any class explicitly marked with the `@InternalApi` (or documented as `@opensearch.internal`) annotation, or not
+explicitly marked by an annotation should not be extended by external implementation components as it does not guarantee backwards compatibility and may change at
+any time. The `@DeprecatedApi` annotation could also be added to any classes annotated with `@PublicApi` (or documented as `@opensearch.api`) or their methods that
+are either changed (with replacement) or planned to be removed across major versions.
+
+The APIs which are designated to be public but have not been stabilized yet should be marked with `@ExperimentalApi` (or documented as `@opensearch.experimental`) 
+annotation. The presence of this annotation signals that API may change at any time (major, minor or even patch releases). In general, the classes annotated with
+`@PublicApi` may expose other classes or methods annotated with `@ExperimentalApi`, in such cases the backward compatibility guarantees would not apply to latter
+(see please [Experimental Development](#experimental-development) for more details).
+
+#### User API
+
+The User API consists of integration specifications (e.g., [Query Domain Specific Language](https://opensearch.org/docs/latest/opensearch/query-dsl/index/),
+[field mappings](https://opensearch.org/docs/latest/opensearch/mappings/)) and endpoints (e.g., [`_search`](https://opensearch.org/docs/latest/api-reference/search/),
+[`_cat`](https://opensearch.org/docs/latest/api-reference/cat/index/)) users rely on to integrate and use OpenSearch. Backwards compatibility is critical to the
+User API, therefore OpenSearch commits to using [semantic versioning](https://opensearch.org/blog/what-is-semver/) for all User facing APIs. To support this
+developers must leverage `Version` checks for any user facing endpoints or API specifications that change across minor versions. Developers must also inform
+users of any changes by adding the `>breaking` label on Pull Requests, adding an entry to the [CHANGELOG](https://github.com/opensearch-project/OpenSearch/blob/main/CHANGELOG.md)
+and a log message to the OpenSearch deprecation log files using the `DeprecationLogger`.
+
+#### Experimental Development
+
+Rapidly developing new features often benefit from several release cycles before committing to an official and long term supported (LTS) API. To enable this cycle OpenSearch
+uses an Experimental Development process leveraging [Feature Flags](https://featureflags.io/feature-flags/). This allows a feature to be developed using the same process as
+a LTS feature but with additional guard rails and communication mechanisms to signal to the users and development community the feature is not yet stable, may change in a future
+release, or be removed altogether. Any Developer or User APIs implemented along with the experimental feature should be marked with `@ExperimentalApi` (or documented as
+`@opensearch.experimental`) annotation to signal the implementation is not subject to LTS and does not follow backwards compatibility guidelines.
+
+### Backports
 
 The Github workflow in [`backport.yml`](.github/workflows/backport.yml) creates backport PRs automatically when the original PR with an appropriate label `backport <backport-branch-name>` is merged to main with the backport workflow run successfully on the PR. For example, if a PR on main needs to be backported to `1.x` branch, add a label `backport 1.x` to the PR and make sure the backport workflow runs on the PR along with other checks. Once this PR is merged to main, the workflow will create a backport PR to the `1.x` branch.
+
+### LineLint
+
+A linter in [`code-hygiene.yml`](.github/workflows/code-hygiene.yml) that validates simple newline and whitespace rules in all sorts of files. It can:
+- Recursively check a directory tree for files that do not end in a newline
+- Automatically fix these files by adding a newline or trimming extra newlines.
+
+Rules are defined in `.linelint.yml`.
+
+Executing the binary will automatically search the local directory tree for linting errors.
+
+    linelint .
+
+Pass a list of files or directories to limit your search.
+
+    linelint README.md LICENSE
+
+### Lucene Snapshots
+
+The Github workflow in [lucene-snapshots.yml](.github/workflows/lucene-snapshots.yml) is a Github worfklow executable by maintainers to build a top-down snapshot build of lucene.
+These snapshots are available to test compatibility with upcoming changes to Lucene by updating the version at [version.properties](buildsrc/version.properties) with the `version-snapshot-sha` version. Example: `lucene = 10.0.0-snapshot-2e941fc`.
+
+### Flaky Tests
+
+OpenSearch has a very large test suite with long running, often failing (flaky), integration tests. Such individual tests are labelled as [Flaky Random Test Failure](https://github.com/opensearch-project/OpenSearch/issues?q=is%3Aopen+is%3Aissue+label%3A%22flaky-test%22). Your help is wanted fixing these!
+
+If you encounter a build/test failure in CI that is unrelated to the change in your pull request, it may be a known flaky test, or a new test failure.
+
+1. Follow failed CI links, and locate the failing test(s).
+2. Copy-paste the failure into a comment of your PR.
+3. Search through [issues](https://github.com/opensearch-project/OpenSearch/issues?q=is%3Aopen+is%3Aissue+label%3A%22flaky-test%22) using the name of the failed test for whether this is a known flaky test.
+5. If an existing issue is found, paste a link to the known issue in a comment to your PR.
+6. If no existing issue is found, open one.
+7. Retry CI via the GitHub UX or by pushing an update to your PR.
diff --git a/MAINTAINERS.md b/MAINTAINERS.md
index db6cd6c0f3309..42a8a439445ca 100644
--- a/MAINTAINERS.md
+++ b/MAINTAINERS.md
@@ -1,29 +1,42 @@
-## Maintainers
+## Overview
 
-| Maintainer | GitHub ID | Affiliation |
-| --------------- | --------- | ----------- |
-| Abbas Hussain | [abbashus](https://github.com/abbashus) | Amazon |
-| Charlotte Henkle | [CEHENKLE](https://github.com/CEHENKLE) | Amazon |
-| Himanshu Setia | [setiah](https://github.com/setiah) | Amazon |
-| Nick Knize | [nknize](https://github.com/nknize) | Amazon |
-| Rabi Panda | [adnapibar](https://github.com/adnapibar) | Amazon |
-| Sarat Vemulapalli | [saratvemulapalli](https://github.com/saratvemulapalli) | Amazon |
-| Tianli Feng | [tlfeng](https://github.com/tlfeng) | Amazon |
-| Gopala Krishna Ambareesh | [krishna-ggk](https://github.com/krishna-ggk) |Amazon |
-| Vengadanathan Srinivasan | [vengadanathan-s](https://github.com/vengadanathan-s) | Amazon |
-| Shweta Thareja |[shwetathareja](https://github.com/shwetathareja) | Amazon |
-| Itiyama Sadana | [itiyamas](https://github.com/itiyamas) | Amazon |
-| Daniel "dB." Doubrovkine | [dblock](https://github.com/dblock) | Amazon |
-| Andrew Ross   | [andross](https://github.com/andrross)| Amazon |
-| Vacha Shah | [VachaShah](https://github.com/VachaShah) | Amazon |
-| Anas Alkouz | [anasalkouz](https://github.com/anasalkouz) | Amazon |
-| Megha Sai Kavikondala | [meghasaik](https://github.com/meghasaik) | Amazon |
-| Rishikesh Pasham | [Rishikesh1159](https://github.com/Rishikesh1159) | Amazon|
-| Xue Zhou | [xuezhou25](https://github.com/xuezhou25) | Amazon |
-| Kartik Ganesh | [kartg](https://github.com/kartg) | Amazon |
-| Marc Handalian | [mch2](https://github.com/mch2) | Amazon |
-| Ryan Bogan | [ryanbogan](https://github.com/ryanbogan) | Amazon |
-| Owais Kazi | [owaiskazi19](https://github.com/owaiskazi19) | Amazon |
+This document contains a list of maintainers in this repo. See [opensearch-project/.github/RESPONSIBILITIES.md](https://github.com/opensearch-project/.github/blob/main/RESPONSIBILITIES.md#maintainer-responsibilities) that explains what the role of maintainer means, what maintainers do in this and other repos, and how they should be doing it. If you're interested in contributing, and becoming a maintainer, see [CONTRIBUTING](CONTRIBUTING.md).
 
+## Current Maintainers
 
-[This document](https://github.com/opensearch-project/.github/blob/main/MAINTAINERS.md) explains what maintainers do in this repo, and how they should be doing it. If you're interested in contributing, see [CONTRIBUTING](CONTRIBUTING.md).
+| Maintainer               | GitHub ID                                               | Affiliation |
+|--------------------------| ------------------------------------------------------- | ----------- |
+| Abbas Hussain            | [abbashus](https://github.com/abbashus)                 | Meta        |
+| Anas Alkouz              | [anasalkouz](https://github.com/anasalkouz)             | Amazon      |
+| Andrew Ross              | [andrross](https://github.com/andrross)                 | Amazon      |
+| Andriy Redko             | [reta](https://github.com/reta)                         | Aiven       |
+| Bukhtawar Khan           | [Bukhtawar](https://github.com/Bukhtawar)               | Amazon      |
+| Charlotte Henkle         | [CEHENKLE](https://github.com/CEHENKLE)                 | Amazon      |
+| Dan Widdis               | [dbwiddis](https://github.com/dbwiddis)                 | Amazon      |
+| Daniel "dB." Doubrovkine | [dblock](https://github.com/dblock)                     | Amazon      |
+| Gaurav Bafna             | [gbbafna](https://github.com/gbbafna)                   | Amazon      |
+| Himanshu Setia           | [setiah](https://github.com/setiah)                     | Amazon      |
+| Kartik Ganesh            | [kartg](https://github.com/kartg)                       | Amazon      |
+| Kunal Kotwani            | [kotwanikunal](https://github.com/kotwanikunal)         | Amazon      |
+| Marc Handalian           | [mch2](https://github.com/mch2)                         | Amazon      |
+| Michael Froh             | [msfroh](https://github.com/msfroh)                     | Amazon      |
+| Nick Knize               | [nknize](https://github.com/nknize)                     | Amazon      |
+| Owais Kazi               | [owaiskazi19](https://github.com/owaiskazi19)           | Amazon      |
+| Peter Nied               | [peternied](https://github.com/peternied)               | Amazon      |
+| Rabi Panda               | [adnapibar](https://github.com/adnapibar)               | Independent |
+| Rishikesh Pasham         | [Rishikesh1159](https://github.com/Rishikesh1159)       | Amazon      |
+| Ryan Bogan               | [ryanbogan](https://github.com/ryanbogan)               | Amazon      |
+| Sachin Kale              | [sachinpkale](https://github.com/sachinpkale)           | Amazon      |
+| Sarat Vemulapalli        | [saratvemulapalli](https://github.com/saratvemulapalli) | Amazon      |
+| Shweta Thareja           | [shwetathareja](https://github.com/shwetathareja)       | Amazon      |
+| Sorabh Hamirwasia        | [sohami](https://github.com/sohami)                     | Amazon      |
+| Suraj Singh              | [dreamer-89](https://github.com/dreamer-89)             | Amazon      |
+| Tianli Feng              | [tlfeng](https://github.com/tlfeng)                     | Amazon      |
+| Vacha Shah               | [VachaShah](https://github.com/VachaShah)               | Amazon      |
+
+## Emeritus
+
+| Maintainer              | GitHub ID                                   | Affiliation |
+|-------------------------|---------------------------------------------|-------------|
+| Megha Sai Kavikondala   | [meghasaik](https://github.com/meghasaik)   | Amazon      |
+| Xue Zhou                | [xuezhou25](https://github.com/xuezhou25)   | Amazon      |
diff --git a/README.md b/README.md
index 6a9a2a69d7367..1b7103191e22f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,14 @@
 <img src="https://opensearch.org/assets/img/opensearch-logo-themed.svg" height="64px">
 
+[![Chat](https://img.shields.io/badge/chat-on%20forums-blue)](https://forum.opensearch.org/c/opensearch/)
+[![Documentation](https://img.shields.io/badge/documentation-reference-blue)](https://opensearch.org/docs/latest/opensearch/index/)
+[![codecov](https://codecov.io/gh/opensearch-project/OpenSearch/branch/2.x/graph/badge.svg)](https://codecov.io/gh/opensearch-project/OpenSearch)
+[![GHA gradle check](https://github.com/opensearch-project/OpenSearch/actions/workflows/gradle-check.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/gradle-check.yml)
+[![GHA validate pull request](https://github.com/opensearch-project/OpenSearch/actions/workflows/wrapper.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/wrapper.yml)
+[![GHA precommit](https://github.com/opensearch-project/OpenSearch/actions/workflows/precommit.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/precommit.yml)
+[![Jenkins gradle check job](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fbuild.ci.opensearch.org%2Fjob%2Fgradle-check%2F&label=Jenkins%20Gradle%20Check)](https://build.ci.opensearch.org/job/gradle-check/)
+
+
 - [Welcome!](#welcome)
 - [Project Resources](#project-resources)
 - [Code of Conduct](#code-of-conduct)
@@ -10,7 +19,7 @@
 
 ## Welcome!
 
-**OpenSearch** is [a community-driven, open source fork](https://aws.amazon.com/blogs/opensource/introducing-opensearch/) of [Elasticsearch](https://en.wikipedia.org/wiki/Elasticsearch) and [Kibana](https://en.wikipedia.org/wiki/Kibana) following the [licence change](https://opensource.org/node/1099) in early 2021. We're looking to sustain (and evolve!) a search and analytics suite for the multitude of businesses who are dependent on the rights granted by the original, [Apache v2.0 License](LICENSE.txt).
+**OpenSearch** is [a community-driven, open source fork](https://aws.amazon.com/blogs/opensource/introducing-opensearch/) of [Elasticsearch](https://en.wikipedia.org/wiki/Elasticsearch) and [Kibana](https://en.wikipedia.org/wiki/Kibana) following the [license change](https://blog.opensource.org/the-sspl-is-not-an-open-source-license/) in early 2021. We're looking to sustain (and evolve!) a search and analytics suite for the multitude of businesses who are dependent on the rights granted by the original, [Apache v2.0 License](LICENSE.txt).
 
 ## Project Resources
 
@@ -45,4 +54,4 @@ Copyright OpenSearch Contributors. See [NOTICE](NOTICE.txt) for details.
 
 OpenSearch is a registered trademark of Amazon Web Services.
 
-OpenSearch includes certain Apache-licensed Elasticsearch code from Elasticsearch B.V. and other source code. Elasticsearch B.V. is not the source of that other source code. ELASTICSEARCH is a registered trademark of Elasticsearch B.V.
\ No newline at end of file
+OpenSearch includes certain Apache-licensed Elasticsearch code from Elasticsearch B.V. and other source code. Elasticsearch B.V. is not the source of that other source code. ELASTICSEARCH is a registered trademark of Elasticsearch B.V.
diff --git a/RELEASING.md b/RELEASING.md
index 50bb965b8d551..1ef59446f6e31 100644
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -1,3 +1,3 @@
 ## Releasing
 
-This project follows [OpenSearch project branching, labelling, and releasing](https://github.com/opensearch-project/.github/blob/main/RELEASING.md).
\ No newline at end of file
+This project follows [OpenSearch project branching, labelling, and releasing](https://github.com/opensearch-project/.github/blob/main/RELEASING.md).
diff --git a/SECURITY.md b/SECURITY.md
index 0b85ca04ed260..b86292104335f 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -1,3 +1,3 @@
 ## Reporting a Vulnerability
 
-If you discover a potential security issue in this project we ask that you notify AWS/Amazon Security via our [vulnerability reporting page](http://aws.amazon.com/security/vulnerability-reporting/) or directly via email to aws-security@amazon.com. Please do **not** create a public GitHub issue.
\ No newline at end of file
+If you discover a potential security issue in this project we ask that you notify AWS/Amazon Security via our [vulnerability reporting page](http://aws.amazon.com/security/vulnerability-reporting/) or directly via email to aws-security@amazon.com. Please do **not** create a public GitHub issue.
diff --git a/TESTING.md b/TESTING.md
index 4a2a786469b67..06533cd5c170a 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -13,6 +13,7 @@ OpenSearch uses [jUnit](https://junit.org/junit5/) for testing, it also uses ran
   - [Test groups](#test-groups)
   - [Load balancing and caches](#load-balancing-and-caches)
   - [Test compatibility](#test-compatibility)
+  - [Retries](#retries)
   - [Miscellaneous](#miscellaneous)
 - [Running verification tasks](#running-verification-tasks)
 - [Testing the REST layer](#testing-the-rest-layer)
@@ -160,6 +161,10 @@ It is possible to provide a version that allows to adapt the tests' behaviour to
 
     ./gradlew test -Dtests.compatibility=1.0.0
 
+## Retries
+
+The goal of tests is to be completely deterministic such that any test failure can be easily and reliably reproduced. However, the reality is that many OpenSearch integration tests have non-deterministic behavior which results in rare test failures that cannot be easily reproduced even using the same random test seed. To mitigate the pain of frequent non-reproducible test failures, limited retries have been introduced using the Gradle [test-retry](https://plugins.gradle.org/plugin/org.gradle.test-retry) plugin. The known flaky tests are explicitly listed in the test-retry configuration of the build.gradle file. This is intended as a temporary mitigation for existing flakiness, and as such new tests should not be added to the retry list. Any new addition to the retry list must provide a thorough rationale as to why adding retries is the right thing to do as opposed to fixing the underlying flakiness. Existing flaky tests are tracked in GitHub with the [Flaky Random Test Failure](https://github.com/opensearch-project/OpenSearch/issues?q=is%3Aopen+is%3Aissue+label%3A%22flaky-test%22) label.
+
 ## Miscellaneous
 
 Run all tests without stopping on errors (inspect log files).
@@ -245,7 +250,7 @@ The YAML REST tests support all the options provided by the randomized runner, p
 
 -   `tests.rest.suite`: comma separated paths of the test suites to be run (by default loaded from /rest-api-spec/test). It is possible to run only a subset of the tests providing a sub-folder or even a single yaml file (the default /rest-api-spec/test prefix is optional when files are loaded from classpath) e.g. `-Dtests.rest.suite=index,get,create/10_with_id`
 
--   `tests.rest.blacklist`: comma separated globs that identify tests that are denylisted and need to be skipped e.g. `-Dtests.rest.blacklist=index/**/Index document,get/10_basic/**`
+-   `tests.rest.denylist`: comma separated globs that identify tests that are denylisted and need to be skipped e.g. `-Dtests.rest.denylist=index/**/Index document,get/10_basic/**`
 
 Java REST tests can be run with the "javaRestTest" task.
 
@@ -383,6 +388,10 @@ Use -Dtest.class and -Dtests.method to run a specific bwcTest test. For example
      -Dtests.class=org.opensearch.upgrades.RecoveryIT \
      -Dtests.method=testHistoryUUIDIsGenerated
 
+Use `-PcustomDistributionDownloadType=bundle` to run the bwcTest against the test cluster with latest CI distribution bundle set up for the specified version; this property is default to min and exclusive choices between `bundle` and `min`:
+
+    ./gradlew bwcTest -PcustomDistributionDownloadType=bundle
+
 When running `./gradlew check`, minimal bwc checks are also run against compatible versions that are not yet released.
 
 ## BWC Testing against a specific remote/branch
diff --git a/benchmarks/build.gradle b/benchmarks/build.gradle
index faaeb33d80ff7..02aa9319cc583 100644
--- a/benchmarks/build.gradle
+++ b/benchmarks/build.gradle
@@ -32,10 +32,16 @@ import org.opensearch.gradle.info.BuildParams
 
 apply plugin: 'opensearch.build'
 apply plugin: 'application'
-mainClassName = 'org.openjdk.jmh.Main'
 
 assemble.enabled = false
-archivesBaseName = 'opensearch-benchmarks'
+
+application {
+  mainClass = 'org.openjdk.jmh.Main'
+}
+
+base {
+  archivesBaseName = 'opensearch-benchmarks'
+}
 
 test.enabled = false
 
@@ -67,12 +73,6 @@ dependenciesInfo.enabled = false
 
 thirdPartyAudit.ignoreViolations(
   // these classes intentionally use JDK internal API (and this is ok since the project is maintained by Oracle employees)
-  'org.openjdk.jmh.profile.AbstractHotspotProfiler',
-  'org.openjdk.jmh.profile.HotspotThreadProfiler',
-  'org.openjdk.jmh.profile.HotspotClassloadingProfiler',
-  'org.openjdk.jmh.profile.HotspotCompilationProfiler',
-  'org.openjdk.jmh.profile.HotspotMemoryProfiler',
-  'org.openjdk.jmh.profile.HotspotRuntimeProfiler',
   'org.openjdk.jmh.util.Utils'
 )
 
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/index/mapper/CustomBinaryDocValuesFieldBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/index/mapper/CustomBinaryDocValuesFieldBenchmark.java
new file mode 100644
index 0000000000000..7307bec088d02
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/index/mapper/CustomBinaryDocValuesFieldBenchmark.java
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.benchmark.index.mapper;
+
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.index.mapper.BinaryFieldMapper;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
+
+@Warmup(iterations = 1)
+@Measurement(iterations = 1)
+@Fork(1)
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+@SuppressWarnings("unused") // invoked by benchmarking framework
+public class CustomBinaryDocValuesFieldBenchmark {
+
+    static final String FIELD_NAME = "dummy";
+    static final String SEED_VALUE = "seed";
+
+    @Benchmark
+    public void add(CustomBinaryDocValuesFieldBenchmark.BenchmarkParameters parameters, Blackhole blackhole) {
+        // Don't use the parameter binary doc values object.
+        // Start with a fresh object every call and add maximum number of entries
+        BinaryFieldMapper.CustomBinaryDocValuesField customBinaryDocValuesField = new BinaryFieldMapper.CustomBinaryDocValuesField(
+            FIELD_NAME,
+            new BytesRef(SEED_VALUE).bytes
+        );
+        for (int i = 0; i < parameters.maximumNumberOfEntries; ++i) {
+            ThreadLocalRandom.current().nextBytes(parameters.bytes);
+            customBinaryDocValuesField.add(parameters.bytes);
+        }
+    }
+
+    @Benchmark
+    public void binaryValue(CustomBinaryDocValuesFieldBenchmark.BenchmarkParameters parameters, Blackhole blackhole) {
+        blackhole.consume(parameters.customBinaryDocValuesField.binaryValue());
+    }
+
+    @State(Scope.Benchmark)
+    public static class BenchmarkParameters {
+        @Param({ "8", "32", "128", "512" })
+        int maximumNumberOfEntries;
+
+        @Param({ "8", "32", "128", "512" })
+        int entrySize;
+
+        BinaryFieldMapper.CustomBinaryDocValuesField customBinaryDocValuesField;
+        byte[] bytes;
+
+        @Setup
+        public void setup() {
+            customBinaryDocValuesField = new BinaryFieldMapper.CustomBinaryDocValuesField(FIELD_NAME, new BytesRef(SEED_VALUE).bytes);
+            bytes = new byte[entrySize];
+            for (int i = 0; i < maximumNumberOfEntries; ++i) {
+                ThreadLocalRandom.current().nextBytes(bytes);
+                customBinaryDocValuesField.add(bytes);
+            }
+        }
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/AllocationBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/AllocationBenchmark.java
index c89bf3d1b577c..1faf522f3a1c9 100644
--- a/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/AllocationBenchmark.java
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/AllocationBenchmark.java
@@ -31,17 +31,6 @@
 
 package org.opensearch.benchmark.routing.allocation;
 
-import org.openjdk.jmh.annotations.Benchmark;
-import org.openjdk.jmh.annotations.BenchmarkMode;
-import org.openjdk.jmh.annotations.Fork;
-import org.openjdk.jmh.annotations.Measurement;
-import org.openjdk.jmh.annotations.Mode;
-import org.openjdk.jmh.annotations.OutputTimeUnit;
-import org.openjdk.jmh.annotations.Param;
-import org.openjdk.jmh.annotations.Scope;
-import org.openjdk.jmh.annotations.Setup;
-import org.openjdk.jmh.annotations.State;
-import org.openjdk.jmh.annotations.Warmup;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -53,6 +42,17 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.common.settings.Settings;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
 
 import java.util.HashMap;
 import java.util.Map;
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/Allocators.java b/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/Allocators.java
index d700b9dab2cf3..482a58f87086e 100644
--- a/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/Allocators.java
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/routing/allocation/Allocators.java
@@ -45,8 +45,8 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/TermsReduceBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/TermsReduceBenchmark.java
index b549de555aca1..5073858848e05 100644
--- a/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/TermsReduceBenchmark.java
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/TermsReduceBenchmark.java
@@ -40,14 +40,14 @@
 import org.opensearch.action.search.SearchPhaseController;
 import org.opensearch.action.search.SearchProgressListener;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchShardTarget;
@@ -57,6 +57,7 @@
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.MultiBucketConsumerService;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.query.QuerySearchResult;
@@ -170,15 +171,14 @@ private StringTerms newTerms(Random rand, BytesRef[] dict, boolean withNested) {
                 "terms",
                 BucketOrder.key(true),
                 BucketOrder.count(false),
-                topNSize,
-                1,
                 Collections.emptyMap(),
                 DocValueFormat.RAW,
                 numShards,
                 true,
                 0,
                 buckets,
-                0
+                0,
+                new TermsAggregator.BucketCountThresholds(1, 0, topNSize, numShards)
             );
         }
 
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/bucket/terms/StringTermsSerializationBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/bucket/terms/StringTermsSerializationBenchmark.java
index 6d8721ce64090..b98a257dfbf48 100644
--- a/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/bucket/terms/StringTermsSerializationBenchmark.java
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/search/aggregations/bucket/terms/StringTermsSerializationBenchmark.java
@@ -34,12 +34,13 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.io.stream.DelayableWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.BenchmarkMode;
 import org.openjdk.jmh.annotations.Fork;
@@ -64,9 +65,7 @@
 @State(Scope.Benchmark)
 public class StringTermsSerializationBenchmark {
     private static final NamedWriteableRegistry REGISTRY = new NamedWriteableRegistry(
-        org.opensearch.common.collect.List.of(
-            new NamedWriteableRegistry.Entry(InternalAggregation.class, StringTerms.NAME, StringTerms::new)
-        )
+        List.of(new NamedWriteableRegistry.Entry(InternalAggregation.class, StringTerms.NAME, StringTerms::new))
     );
     @Param(value = { "1000" })
     private int buckets;
@@ -75,30 +74,27 @@ public class StringTermsSerializationBenchmark {
 
     @Setup
     public void initResults() {
-        results = DelayableWriteable.referencing(InternalAggregations.from(org.opensearch.common.collect.List.of(newTerms(true))));
+        results = DelayableWriteable.referencing(InternalAggregations.from(List.of(newTerms(true))));
     }
 
     private StringTerms newTerms(boolean withNested) {
         List<StringTerms.Bucket> resultBuckets = new ArrayList<>(buckets);
         for (int i = 0; i < buckets; i++) {
-            InternalAggregations inner = withNested
-                ? InternalAggregations.from(org.opensearch.common.collect.List.of(newTerms(false)))
-                : InternalAggregations.EMPTY;
+            InternalAggregations inner = withNested ? InternalAggregations.from(List.of(newTerms(false))) : InternalAggregations.EMPTY;
             resultBuckets.add(new StringTerms.Bucket(new BytesRef("test" + i), i, inner, false, 0, DocValueFormat.RAW));
         }
         return new StringTerms(
             "test",
             BucketOrder.key(true),
             BucketOrder.key(true),
-            buckets,
-            1,
             null,
             DocValueFormat.RAW,
             buckets,
             false,
             100000,
             resultBuckets,
-            0
+            0,
+            new TermsAggregator.BucketCountThresholds(1, 0, buckets, buckets)
         );
     }
 
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/store/remote/filecache/FileCacheBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/store/remote/filecache/FileCacheBenchmark.java
new file mode 100644
index 0000000000000..7cd8c672f45df
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/store/remote/filecache/FileCacheBenchmark.java
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.benchmark.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.index.store.remote.filecache.CachedIndexInput;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheFactory;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Simple benchmark test of {@link FileCache}. It uses a uniform random distribution
+ * of keys, which is very simple but unlikely to be representative of any real life
+ * workload.
+ */
+@Warmup(iterations = 1)
+@Measurement(iterations = 1)
+@Fork(1)
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+@Threads(8)
+@SuppressWarnings("unused") // invoked by benchmarking framework
+public class FileCacheBenchmark {
+    private static final CachedIndexInput INDEX_INPUT = new FixedSizeStubIndexInput();
+
+    @Benchmark
+    public void get(CacheParameters parameters, Blackhole blackhole) {
+        blackhole.consume(parameters.fileCache.get(randomKeyInCache(parameters)));
+    }
+
+    @Benchmark
+    public void replace(CacheParameters parameters, Blackhole blackhole) {
+        blackhole.consume(parameters.fileCache.put(randomKeyInCache(parameters), INDEX_INPUT));
+    }
+
+    @Benchmark
+    public void put(CacheParameters parameters, Blackhole blackhole) {
+        blackhole.consume(parameters.fileCache.put(randomKeyNotInCache(parameters), INDEX_INPUT));
+    }
+
+    @Benchmark
+    public void remove(CacheParameters parameters) {
+        parameters.fileCache.remove(randomKeyInCache(parameters));
+    }
+
+    private static Path randomKeyInCache(CacheParameters parameters) {
+        int i = ThreadLocalRandom.current().nextInt(parameters.maximumNumberOfEntries);
+        return Paths.get(Integer.toString(i));
+    }
+
+    private static Path randomKeyNotInCache(CacheParameters parameters) {
+        int i = ThreadLocalRandom.current().nextInt(parameters.maximumNumberOfEntries, parameters.maximumNumberOfEntries * 2);
+        return Paths.get(Integer.toString(i));
+    }
+
+    @State(Scope.Benchmark)
+    public static class CacheParameters {
+        @Param({ "65536", "1048576" })
+        int maximumNumberOfEntries;
+
+        @Param({ "1", "8" })
+        int concurrencyLevel;
+
+        FileCache fileCache;
+
+        @Setup
+        public void setup() {
+            fileCache = FileCacheFactory.createConcurrentLRUFileCache(
+                (long) maximumNumberOfEntries * INDEX_INPUT.length(),
+                concurrencyLevel,
+                new NoopCircuitBreaker(CircuitBreaker.REQUEST)
+            );
+            for (long i = 0; i < maximumNumberOfEntries; i++) {
+                final Path key = Paths.get(Long.toString(i));
+                fileCache.put(key, INDEX_INPUT);
+                fileCache.decRef(key);
+            }
+        }
+    }
+
+    /**
+     * Stubbed out IndexInput that does nothing but report a fixed size
+     */
+    private static class FixedSizeStubIndexInput implements CachedIndexInput {
+        @Override
+        public IndexInput getIndexInput() {
+            return null;
+        }
+
+        @Override
+        public long length() {
+            return 1024 * 1024 * 8; // 8MiB
+        }
+
+        @Override
+        public boolean isClosed() {
+            return false;
+        }
+
+        @Override
+        public void close() throws Exception {
+
+        }
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/benchmark/time/NanoTimeVsCurrentTimeMillisBenchmark.java b/benchmarks/src/main/java/org/opensearch/benchmark/time/NanoTimeVsCurrentTimeMillisBenchmark.java
new file mode 100644
index 0000000000000..dfa0a8538108e
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/benchmark/time/NanoTimeVsCurrentTimeMillisBenchmark.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.benchmark.time;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+
+import java.util.concurrent.TimeUnit;
+
+@Fork(3)
+@Warmup(iterations = 10)
+@Measurement(iterations = 20)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Benchmark)
+@SuppressWarnings("unused") // invoked by benchmarking framework
+public class NanoTimeVsCurrentTimeMillisBenchmark {
+    private volatile long var = 0;
+
+    @Benchmark
+    public long currentTimeMillis() {
+        return System.currentTimeMillis();
+    }
+
+    @Benchmark
+    public long nanoTime() {
+        return System.nanoTime();
+    }
+
+    /*
+    * this acts as upper bound of how time is cached in org.opensearch.threadpool.ThreadPool
+    * */
+    @Benchmark
+    public long accessLongVar() {
+        return var++;
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/common/ArrayRoundingBenchmark.java b/benchmarks/src/main/java/org/opensearch/common/ArrayRoundingBenchmark.java
new file mode 100644
index 0000000000000..64c0a9e1d7aa6
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/common/ArrayRoundingBenchmark.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.Random;
+import java.util.function.Supplier;
+
+@Fork(value = 3)
+@Warmup(iterations = 3, time = 1)
+@Measurement(iterations = 1, time = 1)
+@BenchmarkMode(Mode.Throughput)
+public class ArrayRoundingBenchmark {
+
+    @Benchmark
+    public void round(Blackhole bh, Options opts) {
+        Rounding.Prepared rounding = opts.supplier.get();
+        for (long key : opts.queries) {
+            bh.consume(rounding.round(key));
+        }
+    }
+
+    @State(Scope.Benchmark)
+    public static class Options {
+        @Param({
+            "1",
+            "2",
+            "3",
+            "4",
+            "5",
+            "6",
+            "7",
+            "8",
+            "9",
+            "10",
+            "12",
+            "14",
+            "16",
+            "18",
+            "20",
+            "22",
+            "24",
+            "26",
+            "29",
+            "32",
+            "37",
+            "41",
+            "45",
+            "49",
+            "54",
+            "60",
+            "64",
+            "74",
+            "83",
+            "90",
+            "98",
+            "108",
+            "118",
+            "128",
+            "144",
+            "159",
+            "171",
+            "187",
+            "204",
+            "229",
+            "256" })
+        public Integer size;
+
+        @Param({ "binary", "linear" })
+        public String type;
+
+        @Param({ "uniform", "skewed_edge", "skewed_center" })
+        public String distribution;
+
+        public long[] queries;
+        public Supplier<Rounding.Prepared> supplier;
+
+        @Setup
+        public void setup() {
+            Random random = new Random(size);
+            long[] values = new long[size];
+            for (int i = 1; i < values.length; i++) {
+                values[i] = values[i - 1] + 100;
+            }
+
+            long range = values[values.length - 1] - values[0] + 100;
+            long mean, stddev;
+            queries = new long[1000000];
+
+            switch (distribution) {
+                case "uniform": // all values equally likely.
+                    for (int i = 0; i < queries.length; i++) {
+                        queries[i] = values[0] + (nextPositiveLong(random) % range);
+                    }
+                    break;
+                case "skewed_edge": // distribution centered at p90 with ± 5% stddev.
+                    mean = values[0] + (long) (range * 0.9);
+                    stddev = (long) (range * 0.05);
+                    for (int i = 0; i < queries.length; i++) {
+                        queries[i] = Math.max(values[0], mean + (long) (random.nextGaussian() * stddev));
+                    }
+                    break;
+                case "skewed_center": // distribution centered at p50 with ± 5% stddev.
+                    mean = values[0] + (long) (range * 0.5);
+                    stddev = (long) (range * 0.05);
+                    for (int i = 0; i < queries.length; i++) {
+                        queries[i] = Math.max(values[0], mean + (long) (random.nextGaussian() * stddev));
+                    }
+                    break;
+                default:
+                    throw new IllegalArgumentException("invalid distribution: " + distribution);
+            }
+
+            switch (type) {
+                case "binary":
+                    supplier = () -> new Rounding.BinarySearchArrayRounding(values, size, null);
+                    break;
+                case "linear":
+                    supplier = () -> new Rounding.BidirectionalLinearSearchArrayRounding(values, size, null);
+                    break;
+                default:
+                    throw new IllegalArgumentException("invalid type: " + type);
+            }
+        }
+
+        private static long nextPositiveLong(Random random) {
+            return random.nextLong() & Long.MAX_VALUE;
+        }
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/common/hash/HashFunctionBenchmark.java b/benchmarks/src/main/java/org/opensearch/common/hash/HashFunctionBenchmark.java
new file mode 100644
index 0000000000000..8842337a468a1
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/common/hash/HashFunctionBenchmark.java
@@ -0,0 +1,172 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import org.apache.lucene.util.StringHelper;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.Random;
+
+@Fork(value = 3)
+@Warmup(iterations = 1, time = 1)
+@Measurement(iterations = 3, time = 3)
+@BenchmarkMode(Mode.Throughput)
+public class HashFunctionBenchmark {
+
+    @Benchmark
+    public void hash(Blackhole bh, Options opts) {
+        bh.consume(opts.type.hash(opts.data));
+    }
+
+    @State(Scope.Benchmark)
+    public static class Options {
+        @Param({ "MURMUR3", "T1HA1" })
+        public Type type;
+
+        @Param({
+            "1",
+            "2",
+            "3",
+            "4",
+            "5",
+            "6",
+            "7",
+            "8",
+            "9",
+            "10",
+            "12",
+            "14",
+            "16",
+            "18",
+            "21",
+            "24",
+            "28",
+            "32",
+            "36",
+            "41",
+            "47",
+            "54",
+            "62",
+            "71",
+            "81",
+            "90",
+            "100",
+            "112",
+            "125",
+            "139",
+            "156",
+            "174",
+            "194",
+            "220",
+            "245",
+            "272",
+            "302",
+            "339",
+            "384",
+            "431",
+            "488",
+            "547",
+            "608",
+            "675",
+            "763",
+            "863",
+            "967",
+            "1084",
+            "1225",
+            "1372",
+            "1537",
+            "1737",
+            "1929",
+            "2142",
+            "2378",
+            "2664",
+            "3011",
+            "3343",
+            "3778",
+            "4232",
+            "4783",
+            "5310",
+            "5895",
+            "6662",
+            "7529",
+            "8508",
+            "9444",
+            "10483",
+            "11741",
+            "13150",
+            "14597",
+            "16495",
+            "18475",
+            "20877",
+            "23383",
+            "25956",
+            "29071",
+            "32560",
+            "36142",
+            "40841",
+            "46151",
+            "52151",
+            "57888",
+            "65414",
+            "72610",
+            "82050",
+            "91076",
+            "102006",
+            "114247",
+            "127957",
+            "143312",
+            "159077",
+            "176576",
+            "199531",
+            "223475",
+            "250292",
+            "277825",
+            "313943",
+            "351617",
+            "393812" })
+        public Integer length;
+        public byte[] data;
+
+        @Setup
+        public void setup() {
+            data = new byte[length];
+            new Random(0).nextBytes(data);
+        }
+    }
+
+    public enum Type {
+        MURMUR3((data, offset, length) -> StringHelper.murmurhash3_x86_32(data, offset, length, 0)),
+        T1HA1((data, offset, length) -> T1ha1.hash(data, offset, length, 0));
+
+        private final Hasher hasher;
+
+        Type(Hasher hasher) {
+            this.hasher = hasher;
+        }
+
+        public long hash(byte[] data) {
+            return hasher.hash(data, 0, data.length);
+        }
+    }
+
+    @FunctionalInterface
+    interface Hasher {
+        long hash(byte[] data, int offset, int length);
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/common/util/BytesRefHashBenchmark.java b/benchmarks/src/main/java/org/opensearch/common/util/BytesRefHashBenchmark.java
new file mode 100644
index 0000000000000..fef12b6d9f84a
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/common/util/BytesRefHashBenchmark.java
@@ -0,0 +1,249 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.StringHelper;
+import org.opensearch.common.hash.T1ha1;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lease.Releasables;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+@Fork(value = 3)
+@Warmup(iterations = 1, time = 2)
+@Measurement(iterations = 3, time = 5)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+public class BytesRefHashBenchmark {
+    private static final int NUM_TABLES = 20;  // run across many tables so that caches aren't effective
+    private static final int NUM_HITS = 1_000_000;  // num hits per table
+
+    @Benchmark
+    public void add(Blackhole bh, Options opts) {
+        HashTable[] tables = Stream.generate(opts.type::create).limit(NUM_TABLES).toArray(HashTable[]::new);
+
+        for (int hit = 0; hit < NUM_HITS; hit++) {
+            BytesRef key = opts.keys[hit % opts.keys.length];
+            for (HashTable table : tables) {
+                bh.consume(table.add(key));
+            }
+        }
+
+        Releasables.close(tables);
+    }
+
+    @State(Scope.Benchmark)
+    public static class Options {
+        @Param({ "MURMUR3", "T1HA1" })
+        public Type type;
+
+        @Param({
+            "1",
+            "2",
+            "3",
+            "4",
+            "5",
+            "6",
+            "7",
+            "8",
+            "10",
+            "12",
+            "14",
+            "16",
+            "19",
+            "22",
+            "25",
+            "29",
+            "33",
+            "38",
+            "43",
+            "50",
+            "57",
+            "65",
+            "75",
+            "86",
+            "97",
+            "109",
+            "124",
+            "141",
+            "161",
+            "182",
+            "204",
+            "229",
+            "262",
+            "297",
+            "336",
+            "380",
+            "430",
+            "482",
+            "550",
+            "610",
+            "704",
+            "801",
+            "914",
+            "1042",
+            "1178",
+            "1343",
+            "1532",
+            "1716",
+            "1940",
+            "2173",
+            "2456",
+            "2751",
+            "3082",
+            "3514",
+            "4006",
+            "4487",
+            "5026",
+            "5730",
+            "6418",
+            "7317",
+            "8196",
+            "9180",
+            "10374",
+            "11723",
+            "13247",
+            "14837",
+            "16915",
+            "19114",
+            "21599",
+            "24623",
+            "28071",
+            "32001",
+            "36482",
+            "41590",
+            "46581",
+            "52637",
+            "58954",
+            "67208",
+            "76618",
+            "86579",
+            "97835",
+            "109576",
+            "122726",
+            "138681",
+            "156710",
+            "175516",
+            "198334",
+            "222135",
+            "248792",
+            "281135",
+            "320494",
+            "365364",
+            "409208",
+            "466498",
+            "527143",
+            "595672",
+            "667153",
+            "753883",
+            "851888",
+            "971153" })
+        public Integer size;
+
+        @Param({ "5", "28", "59", "105" })
+        public Integer length;
+
+        private BytesRef[] keys;
+
+        @Setup
+        public void setup() {
+            assert size <= Math.pow(26, length) : "key length too small to generate the required number of keys";
+            // Seeding with size will help produce deterministic results for the same size, and avoid similar
+            // looking clusters for different sizes, in case one hash function got unlucky.
+            Random random = new Random(size);
+            Set<BytesRef> seen = new HashSet<>();
+            keys = new BytesRef[size];
+            for (int i = 0; i < size; i++) {
+                BytesRef key;
+                do {
+                    key = new BytesRef(
+                        random.ints(97, 123)
+                            .limit(length)
+                            .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
+                            .toString()
+                    );
+                } while (seen.contains(key));
+                keys[i] = key;
+                seen.add(key);
+            }
+        }
+    }
+
+    public enum Type {
+        MURMUR3(() -> new HashTable() {
+            private final BytesRefHash table = new BytesRefHash(1, 0.6f, key -> {
+                // Repeating the lower bits into upper bits to make the fingerprint work.
+                // Alternatively, use a 64-bit murmur3 hash, but that won't represent the baseline.
+                long h = StringHelper.murmurhash3_x86_32(key.bytes, key.offset, key.length, 0) & 0xFFFFFFFFL;
+                return h | (h << 32);
+            }, BigArrays.NON_RECYCLING_INSTANCE);
+
+            @Override
+            public long add(BytesRef key) {
+                return table.add(key);
+            }
+
+            @Override
+            public void close() {
+                table.close();
+            }
+        }),
+
+        T1HA1(() -> new HashTable() {
+            private final BytesRefHash table = new BytesRefHash(
+                1,
+                0.6f,
+                key -> T1ha1.hash(key.bytes, key.offset, key.length, 0),
+                BigArrays.NON_RECYCLING_INSTANCE
+            );
+
+            @Override
+            public long add(BytesRef key) {
+                return table.add(key);
+            }
+
+            @Override
+            public void close() {
+                table.close();
+            }
+        });
+
+        private final Supplier<HashTable> supplier;
+
+        Type(Supplier<HashTable> supplier) {
+            this.supplier = supplier;
+        }
+
+        public HashTable create() {
+            return supplier.get();
+        }
+    }
+
+    interface HashTable extends Releasable {
+        long add(BytesRef key);
+    }
+}
diff --git a/benchmarks/src/main/java/org/opensearch/common/util/LongHashBenchmark.java b/benchmarks/src/main/java/org/opensearch/common/util/LongHashBenchmark.java
new file mode 100644
index 0000000000000..4d746b790a348
--- /dev/null
+++ b/benchmarks/src/main/java/org/opensearch/common/util/LongHashBenchmark.java
@@ -0,0 +1,425 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.common.lease.Releasable;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+@Fork(value = 3)
+@Warmup(iterations = 1, time = 4)
+@Measurement(iterations = 3, time = 2)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+public class LongHashBenchmark {
+
+    @Benchmark
+    public void add(Blackhole bh, HashTableOptions tableOpts, WorkloadOptions workloadOpts) {
+        try (HashTable table = tableOpts.get(); WorkloadIterator iter = workloadOpts.iter()) {
+            while (iter.hasNext()) {
+                bh.consume(table.add(iter.next()));
+            }
+        }
+    }
+
+    /**
+     * Creates a hash table with varying parameters.
+     */
+    @State(Scope.Benchmark)
+    public static class HashTableOptions {
+
+        @Param({ "LongHash", "ReorganizingLongHash" })
+        public String type;
+
+        @Param({ "1" })
+        public long initialCapacity;
+
+        @Param({ "0.6" })
+        public float loadFactor;
+
+        private Supplier<HashTable> supplier;
+
+        @Setup
+        public void setup() {
+            switch (type) {
+                case "LongHash":
+                    supplier = this::newLongHash;
+                    break;
+                case "ReorganizingLongHash":
+                    supplier = this::newReorganizingLongHash;
+                    break;
+                default:
+                    throw new IllegalArgumentException("invalid hash table type: " + type);
+            }
+        }
+
+        public HashTable get() {
+            return supplier.get();
+        }
+
+        private HashTable newLongHash() {
+            return new HashTable() {
+                private final LongHash table = new LongHash(initialCapacity, loadFactor, BigArrays.NON_RECYCLING_INSTANCE);
+
+                @Override
+                public long add(long key) {
+                    return table.add(key);
+                }
+
+                @Override
+                public void close() {
+                    table.close();
+                }
+            };
+        }
+
+        private HashTable newReorganizingLongHash() {
+            return new HashTable() {
+                private final ReorganizingLongHash table = new ReorganizingLongHash(
+                    initialCapacity,
+                    loadFactor,
+                    BigArrays.NON_RECYCLING_INSTANCE
+                );
+
+                @Override
+                public long add(long key) {
+                    return table.add(key);
+                }
+
+                @Override
+                public void close() {
+                    table.close();
+                }
+            };
+        }
+    }
+
+    /**
+     * Creates a workload with varying parameters.
+     */
+    @State(Scope.Benchmark)
+    public static class WorkloadOptions {
+        public static final int NUM_HITS = 20_000_000;
+
+        /**
+         * Repeat the experiment with growing number of keys.
+         * These values are generated with an exponential growth pattern such that:
+         * value = ceil(previous_value * random_float_between(1.0, 1.14))
+         */
+        @Param({
+            "1",
+            "2",
+            "3",
+            "4",
+            "5",
+            "6",
+            "7",
+            "8",
+            "9",
+            "10",
+            "11",
+            "13",
+            "15",
+            "17",
+            "18",
+            "19",
+            "20",
+            "21",
+            "23",
+            "26",
+            "27",
+            "30",
+            "32",
+            "35",
+            "41",
+            "45",
+            "50",
+            "53",
+            "54",
+            "55",
+            "57",
+            "63",
+            "64",
+            "69",
+            "74",
+            "80",
+            "84",
+            "91",
+            "98",
+            "101",
+            "111",
+            "114",
+            "124",
+            "128",
+            "139",
+            "148",
+            "161",
+            "162",
+            "176",
+            "190",
+            "204",
+            "216",
+            "240",
+            "257",
+            "269",
+            "291",
+            "302",
+            "308",
+            "327",
+            "341",
+            "374",
+            "402",
+            "412",
+            "438",
+            "443",
+            "488",
+            "505",
+            "558",
+            "612",
+            "621",
+            "623",
+            "627",
+            "642",
+            "717",
+            "765",
+            "787",
+            "817",
+            "915",
+            "962",
+            "1011",
+            "1083",
+            "1163",
+            "1237",
+            "1301",
+            "1424",
+            "1541",
+            "1716",
+            "1805",
+            "1817",
+            "1934",
+            "2024",
+            "2238",
+            "2281",
+            "2319",
+            "2527",
+            "2583",
+            "2639",
+            "2662",
+            "2692",
+            "2991",
+            "3201",
+            "3215",
+            "3517",
+            "3681",
+            "3710",
+            "4038",
+            "4060",
+            "4199",
+            "4509",
+            "4855",
+            "5204",
+            "5624",
+            "6217",
+            "6891",
+            "7569",
+            "8169",
+            "8929",
+            "9153",
+            "10005",
+            "10624",
+            "10931",
+            "12070",
+            "12370",
+            "13694",
+            "14227",
+            "15925",
+            "17295",
+            "17376",
+            "18522",
+            "19200",
+            "20108",
+            "21496",
+            "23427",
+            "24224",
+            "26759",
+            "29199",
+            "29897",
+            "32353",
+            "33104",
+            "36523",
+            "38480",
+            "38958",
+            "40020",
+            "44745",
+            "45396",
+            "47916",
+            "49745",
+            "49968",
+            "52231",
+            "53606" })
+        public int size;
+
+        @Param({ "correlated", "uncorrelated", "distinct" })
+        public String dataset;
+
+        private WorkloadIterator iterator;
+
+        @Setup
+        public void setup() {
+            switch (dataset) {
+                case "correlated":
+                    iterator = newCorrelatedWorkload();
+                    break;
+                case "uncorrelated":
+                    iterator = newUncorrelatedWorkload();
+                    break;
+                case "distinct":
+                    iterator = newDistinctWorkload();
+                    break;
+                default:
+                    throw new IllegalArgumentException("invalid dataset: " + dataset);
+            }
+        }
+
+        public WorkloadIterator iter() {
+            return iterator;
+        }
+
+        /**
+         * Simulates monotonically increasing timestamp data with multiple hits mapping to the same key.
+         */
+        private WorkloadIterator newCorrelatedWorkload() {
+            assert NUM_HITS >= size : "ensure hits >= size so that each key is used at least once";
+
+            final long[] data = new long[size];
+            for (int i = 0; i < data.length; i++) {
+                data[i] = 1420070400000L + 3600000L * i;
+            }
+
+            return new WorkloadIterator() {
+                private int count = 0;
+                private int index = 0;
+                private int remaining = NUM_HITS / data.length;
+
+                @Override
+                public boolean hasNext() {
+                    return count < NUM_HITS;
+                }
+
+                @Override
+                public long next() {
+                    if (--remaining <= 0) {
+                        index = (index + 1) % data.length;
+                        remaining = NUM_HITS / data.length;
+                    }
+                    count++;
+                    return data[index];
+                }
+
+                @Override
+                public void reset() {
+                    count = 0;
+                    index = 0;
+                    remaining = NUM_HITS / data.length;
+                }
+            };
+        }
+
+        /**
+         * Simulates uncorrelated data (such as travel distance / fare amount).
+         */
+        private WorkloadIterator newUncorrelatedWorkload() {
+            assert NUM_HITS >= size : "ensure hits >= size so that each key is used at least once";
+
+            final Random random = new Random(0); // fixed seed for reproducible results
+            final long[] data = new long[size];
+            for (int i = 0; i < data.length; i++) {
+                data[i] = Double.doubleToLongBits(20.0 + 80 * random.nextDouble());
+            }
+
+            return new WorkloadIterator() {
+                private int count = 0;
+                private int index = 0;
+
+                @Override
+                public boolean hasNext() {
+                    return count < NUM_HITS;
+                }
+
+                @Override
+                public long next() {
+                    count++;
+                    index = (index + 1) % data.length;
+                    return data[index];
+                }
+
+                @Override
+                public void reset() {
+                    count = 0;
+                    index = 0;
+                }
+            };
+        }
+
+        /**
+         * Simulates workload with high cardinality, i.e., each hit mapping to a different key.
+         */
+        private WorkloadIterator newDistinctWorkload() {
+            return new WorkloadIterator() {
+                private int count = 0;
+
+                @Override
+                public boolean hasNext() {
+                    return count < size;
+                }
+
+                @Override
+                public long next() {
+                    return count++;
+                }
+
+                @Override
+                public void reset() {
+                    count = 0;
+                }
+            };
+        }
+    }
+
+    private interface HashTable extends Releasable {
+        long add(long key);
+    }
+
+    private interface WorkloadIterator extends Releasable {
+        boolean hasNext();
+
+        long next();
+
+        void reset();
+
+        @Override
+        default void close() {
+            reset();
+        }
+    }
+}
diff --git a/build.gradle b/build.gradle
index be5766f327e0d..4b23a8d07dddd 100644
--- a/build.gradle
+++ b/build.gradle
@@ -28,6 +28,9 @@
  * under the License.
  */
 
+import java.nio.charset.StandardCharsets;
+import java.io.ByteArrayOutputStream;
+
 import com.avast.gradle.dockercompose.tasks.ComposePull
 import com.github.jengelman.gradle.plugins.shadow.ShadowPlugin
 import de.thetaphi.forbiddenapis.gradle.ForbiddenApisPlugin
@@ -37,18 +40,24 @@ import org.opensearch.gradle.Version
 import org.opensearch.gradle.VersionProperties
 import org.opensearch.gradle.info.BuildParams
 import org.opensearch.gradle.plugin.PluginBuildPlugin
+import org.opensearch.gradle.tar.SymbolicLinkPreservingTar
 import org.gradle.plugins.ide.eclipse.model.AccessRule
 import org.gradle.plugins.ide.eclipse.model.EclipseJdt
 import org.gradle.plugins.ide.eclipse.model.SourceFolder
-import org.gradle.util.DistributionLocator
-import org.gradle.util.GradleVersion
+import org.gradle.api.Project;
+import org.gradle.process.ExecResult;
+import org.opensearch.gradle.CheckCompatibilityTask
+
 import static org.opensearch.gradle.util.GradleUtils.maybeConfigure
 
 plugins {
   id 'lifecycle-base'
   id 'opensearch.docker-support'
   id 'opensearch.global-build-info'
-  id "com.diffplug.spotless" version "6.3.0" apply false
+  id "com.diffplug.spotless" version "6.20.0" apply false
+  id "org.gradle.test-retry" version "1.5.4" apply false
+  id "test-report-aggregation"
+  id 'jacoco-report-aggregation'
 }
 
 apply from: 'gradle/build-complete.gradle'
@@ -147,6 +156,30 @@ Map<String, String> buildMetadataMap = buildMetadataValue.tokenize(';').collectE
   return [key, value]
 }
 
+    /**
+     * Using 'git' command line (if available), tries to fetch the commit date of the current revision
+     * @return commit date of the current revision or 0 if it is not available
+     */
+long gitRevisionDate = {
+  // Try to get last commit date as Unix timestamp
+  try (ByteArrayOutputStream stdout = new ByteArrayOutputStream()) {
+     ExecResult result = project.exec(spec -> {
+        spec.setIgnoreExitValue(true);
+        spec.setStandardOutput(stdout);
+        spec.commandLine("git", "log", "-1", "--format=%ct");
+     });
+
+    if (result.getExitValue() == 0) {
+      return Long.parseLong(stdout.toString(StandardCharsets.UTF_8).replaceAll("\\s", "")) * 1000; /* seconds to millis */
+    }
+  } catch (IOException | GradleException | NumberFormatException ex) {
+    /* fall back to default Unix epoch timestamp */
+  }
+
+  return 0;
+}()
+
+
 // injecting groovy property variables into all projects
 allprojects {
   project.ext {
@@ -230,9 +263,15 @@ tasks.register("branchConsistency") {
 allprojects {
   // configure compiler options
   tasks.withType(JavaCompile).configureEach { JavaCompile compile ->
+    options.fork = true
+
+    configure(options.forkOptions) {
+      memoryMaximumSize = project.property('options.forkOptions.memoryMaximumSize')
+    }
+
     // See please https://bugs.openjdk.java.net/browse/JDK-8209058
     if (BuildParams.runtimeJavaVersion > JavaVersion.VERSION_11) {
-        compile.options.compilerArgs << '-Werror'
+      compile.options.compilerArgs << '-Werror'
     }
     compile.options.compilerArgs << '-Xlint:auxiliaryclass'
     compile.options.compilerArgs << '-Xlint:cast'
@@ -275,14 +314,24 @@ allprojects {
     // see https://discuss.gradle.org/t/add-custom-javadoc-option-that-does-not-take-an-argument/5959
     javadoc.options.encoding = 'UTF8'
     javadoc.options.addStringOption('Xdoclint:all,-missing', '-quiet')
+    boolean failOnJavadocWarning = project.ext.has('failOnJavadocWarning') ? project.ext.get('failOnJavadocWarning') : true
+    if (failOnJavadocWarning) {
+      javadoc.options.addStringOption('Xwerror', '-quiet')
+    }
+    javadoc.options.tags = ["opensearch.internal", "opensearch.api", "opensearch.experimental"]
+    javadoc.options.addStringOption("-release", java.targetCompatibility.majorVersion)
   }
 
   // support for reproducible builds
-  tasks.withType(AbstractArchiveTask).configureEach {
+  tasks.withType(AbstractArchiveTask).configureEach { task ->
     // ignore file timestamps
     // be consistent in archive file order
-    preserveFileTimestamps = false
-    reproducibleFileOrder = true
+    task.preserveFileTimestamps = false
+    task.reproducibleFileOrder = true
+    if (task instanceof SymbolicLinkPreservingTar) {
+      // Replace file timestamps with latest Git revision date (if available)
+      task.lastModifiedTimestamp = gitRevisionDate
+    }
   }
 
   project.afterEvaluate {
@@ -318,9 +367,10 @@ allprojects {
         } else {
           // Link to non-shadowed dependant projects
           project.javadoc.dependsOn "${upstreamProject.path}:javadoc"
-          String externalLinkName = upstreamProject.archivesBaseName
+          String externalLinkName = upstreamProject.base.archivesBaseName
           String artifactPath = dep.group.replaceAll('\\.', '/') + '/' + externalLinkName.replaceAll('\\.', '/') + '/' + dep.version
-          project.javadoc.options.linksOffline artifactsHost + "/javadoc/" + artifactPath, "${upstreamProject.buildDir}/docs/javadoc/"
+          String projectRelativePath = project.relativePath(upstreamProject.buildDir)
+          project.javadoc.options.linksOffline artifactsHost + "/javadoc/" + artifactPath, "${projectRelativePath}/docs/javadoc/"
         }
       }
       boolean hasShadow = project.plugins.hasPlugin(ShadowPlugin)
@@ -349,6 +399,10 @@ allprojects {
 // the dependency is added.
 gradle.projectsEvaluated {
   allprojects {
+    project.tasks.withType(JavaForkOptions) {
+      maxHeapSize project.property('options.forkOptions.memoryMaximumSize')
+    }
+
     if (project.path == ':test:framework') {
       // :test:framework:test cannot run before and after :server:test
       return
@@ -362,6 +416,9 @@ gradle.projectsEvaluated {
         if (BuildParams.runtimeJavaVersion > JavaVersion.VERSION_17) {
           task.jvmArgs += ["-Djava.security.manager=allow"]
         }
+        if (BuildParams.runtimeJavaVersion >= JavaVersion.VERSION_20) {
+          task.jvmArgs += ["--add-modules=jdk.incubator.vector"]
+        }
       }
     }
 
@@ -384,11 +441,111 @@ gradle.projectsEvaluated {
       }
     }
   }
+
+  dependencies {
+    subprojects.findAll { it.pluginManager.hasPlugin('java') }.forEach {
+      testReportAggregation it
+    }
+    subprojects.findAll { it.pluginManager.hasPlugin('jacoco') }.forEach {
+      jacocoAggregation it
+    }
+  }
+}
+
+// test retry configuration
+subprojects {
+  apply plugin: "org.gradle.test-retry"
+  tasks.withType(Test).configureEach {
+    retry {
+      if (BuildParams.isCi()) {
+        maxRetries = 3
+        maxFailures = 10
+      }
+      failOnPassedAfterRetry = false
+      filter {
+        includeClasses.add("org.opensearch.action.admin.cluster.node.tasks.ResourceAwareTasksTests")
+        includeClasses.add("org.opensearch.action.admin.cluster.tasks.PendingTasksBlocksIT")
+        includeClasses.add("org.opensearch.action.admin.indices.create.CreateIndexIT")
+        includeClasses.add("org.opensearch.action.admin.indices.create.ShrinkIndexIT")
+        includeClasses.add("org.opensearch.aliases.IndexAliasesIT")
+        includeClasses.add("org.opensearch.backwards.MixedClusterClientYamlTestSuiteIT")
+        includeClasses.add("org.opensearch.blocks.SimpleBlocksIT")
+        includeClasses.add("org.opensearch.client.PitIT")
+        includeClasses.add("org.opensearch.client.ReindexIT")
+        includeClasses.add("org.opensearch.cluster.ClusterHealthIT")
+        includeClasses.add("org.opensearch.cluster.allocation.AwarenessAllocationIT")
+        includeClasses.add("org.opensearch.cluster.allocation.ClusterRerouteIT")
+        includeClasses.add("org.opensearch.cluster.coordination.AwarenessAttributeDecommissionIT")
+        includeClasses.add("org.opensearch.cluster.metadata.IndexGraveyardTests")
+        includeClasses.add("org.opensearch.cluster.routing.MovePrimaryFirstTests")
+        includeClasses.add("org.opensearch.cluster.routing.allocation.decider.DiskThresholdDeciderIT")
+        includeClasses.add("org.opensearch.common.util.concurrent.QueueResizableOpenSearchThreadPoolExecutorTests")
+        includeClasses.add("org.opensearch.gateway.RecoveryFromGatewayIT")
+        includeClasses.add("org.opensearch.gateway.ReplicaShardAllocatorIT")
+        includeClasses.add("org.opensearch.http.SearchRestCancellationIT")
+        includeClasses.add("org.opensearch.http.netty4.Netty4HttpServerTransportTests")
+        includeClasses.add("org.opensearch.index.IndexServiceTests")
+        includeClasses.add("org.opensearch.index.IndexSettingsTests")
+        includeClasses.add("org.opensearch.index.SegmentReplicationPressureIT")
+        includeClasses.add("org.opensearch.index.ShardIndexingPressureIT")
+        includeClasses.add("org.opensearch.index.ShardIndexingPressureSettingsIT")
+        includeClasses.add("org.opensearch.index.reindex.BulkByScrollResponseTests")
+        includeClasses.add("org.opensearch.index.reindex.DeleteByQueryBasicTests")
+        includeClasses.add("org.opensearch.index.reindex.UpdateByQueryBasicTests")
+        includeClasses.add("org.opensearch.index.shard.IndexShardIT")
+        includeClasses.add("org.opensearch.index.shard.RemoteIndexShardTests")
+        includeClasses.add("org.opensearch.index.shard.RemoteStoreRefreshListenerTests")
+        includeClasses.add("org.opensearch.index.translog.RemoteFSTranslogTests")
+        includeClasses.add("org.opensearch.indices.DateMathIndexExpressionsIntegrationIT")
+        includeClasses.add("org.opensearch.indices.replication.RemoteStoreReplicationSourceTests")
+        includeClasses.add("org.opensearch.indices.replication.SegmentReplicationAllocationIT")
+        includeClasses.add("org.opensearch.indices.replication.SegmentReplicationIT")
+        includeClasses.add("org.opensearch.indices.replication.SegmentReplicationRelocationIT")
+        includeClasses.add("org.opensearch.indices.replication.SegmentReplicationTargetServiceTests")
+        includeClasses.add("org.opensearch.indices.state.CloseWhileRelocatingShardsIT")
+        includeClasses.add("org.opensearch.monitor.fs.FsHealthServiceTests")
+        includeClasses.add("org.opensearch.recovery.ReplicationCollectionTests")
+        includeClasses.add("org.opensearch.remotestore.CreateRemoteIndexClusterDefaultDocRep")
+        includeClasses.add("org.opensearch.remotestore.CreateRemoteIndexIT")
+        includeClasses.add("org.opensearch.remotestore.CreateRemoteIndexTranslogDisabledIT")
+        includeClasses.add("org.opensearch.remotestore.RemoteIndexPrimaryRelocationIT")
+        includeClasses.add("org.opensearch.remotestore.RemoteStoreBackpressureIT")
+        includeClasses.add("org.opensearch.remotestore.RemoteStoreIT")
+        includeClasses.add("org.opensearch.remotestore.RemoteStoreRefreshListenerIT")
+        includeClasses.add("org.opensearch.remotestore.RemoteStoreStatsIT")
+        includeClasses.add("org.opensearch.remotestore.SegmentReplicationRemoteStoreIT")
+        includeClasses.add("org.opensearch.remotestore.SegmentReplicationUsingRemoteStoreIT")
+        includeClasses.add("org.opensearch.remotestore.multipart.RemoteStoreMultipartIT")
+        includeClasses.add("org.opensearch.repositories.azure.AzureBlobContainerRetriesTests")
+        includeClasses.add("org.opensearch.repositories.azure.AzureBlobStoreRepositoryTests")
+        includeClasses.add("org.opensearch.repositories.gcs.GoogleCloudStorageBlobContainerRetriesTests")
+        includeClasses.add("org.opensearch.repositories.gcs.GoogleCloudStorageBlobStoreRepositoryTests")
+        includeClasses.add("org.opensearch.repositories.s3.S3BlobStoreRepositoryTests")
+        includeClasses.add("org.opensearch.search.ConcurrentSegmentSearchTimeoutIT")
+        includeClasses.add("org.opensearch.search.SearchTimeoutIT")
+        includeClasses.add("org.opensearch.search.SearchWeightedRoutingIT")
+        includeClasses.add("org.opensearch.search.aggregations.bucket.DoubleTermsIT")
+        includeClasses.add("org.opensearch.search.aggregations.bucket.terms.StringTermsIT")
+        includeClasses.add("org.opensearch.search.aggregations.metrics.CardinalityIT")
+        includeClasses.add("org.opensearch.search.backpressure.SearchBackpressureIT")
+        includeClasses.add("org.opensearch.search.basic.SearchWithRandomIOExceptionsIT")
+        includeClasses.add("org.opensearch.search.pit.DeletePitMultiNodeIT")
+        includeClasses.add("org.opensearch.smoketest.SmokeTestMultiNodeClientYamlTestSuiteIT")
+        includeClasses.add("org.opensearch.snapshots.CloneSnapshotIT")
+        includeClasses.add("org.opensearch.snapshots.DedicatedClusterSnapshotRestoreIT")
+        includeClasses.add("org.opensearch.snapshots.RestoreSnapshotIT")
+        includeClasses.add("org.opensearch.snapshots.SnapshotStatusApisIT")
+        includeClasses.add("org.opensearch.test.rest.ClientYamlTestSuiteIT")
+        includeClasses.add("org.opensearch.upgrade.DetectEsInstallationTaskTests")
+      }
+    }
+  }
 }
 
 // eclipse configuration
 allprojects {
   apply plugin: 'eclipse'
+
   // Name all the non-root projects after their path so that paths get grouped together when imported into eclipse.
   if (path != ':') {
     eclipse.project.name = path
@@ -445,25 +602,21 @@ allprojects {
   tasks.named('eclipse') { dependsOn 'cleanEclipse', 'copyEclipseSettings' }
 
   afterEvaluate {
-     tasks.findByName("eclipseJdt")?.configure {
-         dependsOn 'copyEclipseSettings'
-     }
+    tasks.findByName("eclipseJdt")?.configure {
+      dependsOn 'copyEclipseSettings'
+    }
   }
 }
 
 wrapper {
   distributionType = 'ALL'
   doLast {
-    final DistributionLocator locator = new DistributionLocator()
-    final GradleVersion version = GradleVersion.version(wrapper.gradleVersion)
-    final URI distributionUri = locator.getDistributionFor(version, wrapper.distributionType.name().toLowerCase(Locale.ENGLISH))
-    final URI sha256Uri = new URI(distributionUri.toString() + ".sha256")
-    final String sha256Sum = new String(sha256Uri.toURL().bytes)
-    wrapper.getPropertiesFile() << "distributionSha256Sum=${sha256Sum}\n"
+    def sha256Sum = new String(new URL(getDistributionUrl() + ".sha256").bytes)
+    propertiesFile << "distributionSha256Sum=${sha256Sum}\n"
     println "Added checksum to wrapper properties"
     // Update build-tools to reflect the Gradle upgrade
     // TODO: we can remove this once we have tests to make sure older versions work.
-    project(':build-tools').file('src/main/resources/minimumGradleVersion').text = gradleVersion
+    project(':build-tools').file('src/main/resources/minimumGradleVersion').text = gradleVersion + "\n"
     println "Updated minimum Gradle Version"
   }
 }
@@ -545,3 +698,32 @@ subprojects {
     }
   }
 }
+
+reporting {
+  reports {
+    testAggregateTestReport(AggregateTestReport) {
+      testType = TestSuiteType.UNIT_TEST
+    }
+  }
+}
+
+// Enable XML test reports for Jenkins integration
+tasks.withType(TestTaskReports).configureEach {
+  junitXml.enabled = true
+}
+
+tasks.named(JavaBasePlugin.CHECK_TASK_NAME) {
+  dependsOn tasks.named('testAggregateTestReport', TestReport)
+}
+
+tasks.register('checkCompatibility', CheckCompatibilityTask) {
+  description('Checks the compatibility with child components')
+}
+
+allprojects { project ->
+  project.afterEvaluate {
+    if (project.tasks.findByName('publishToMavenLocal')) {
+      checkCompatibility.dependsOn(project.tasks.publishToMavenLocal)
+    }
+  }
+}
diff --git a/buildSrc/build.gradle b/buildSrc/build.gradle
index f940eec593306..66f99b93bcedb 100644
--- a/buildSrc/build.gradle
+++ b/buildSrc/build.gradle
@@ -61,7 +61,7 @@ Properties props = VersionPropertiesLoader.loadBuildSrcVersion(project.file('ver
 version = props.getProperty("opensearch")
 
 def generateVersionProperties = tasks.register("generateVersionProperties", WriteProperties) {
-  outputFile = "${buildDir}/version.properties"
+  destinationFile = file("${buildDir}/version.properties")
   comment = 'Generated version properties'
   properties(props)
 }
@@ -102,31 +102,47 @@ dependencies {
 
   api localGroovy()
 
-  api 'commons-codec:commons-codec:1.15'
-  api 'org.apache.commons:commons-compress:1.21'
-  api 'org.apache.ant:ant:1.10.12'
-  api 'com.netflix.nebula:gradle-extra-configurations-plugin:7.0.0'
-  api 'com.netflix.nebula:nebula-publishing-plugin:4.4.4'
-  api 'com.netflix.nebula:gradle-info-plugin:7.1.3'
-  api 'org.apache.rat:apache-rat:0.13'
-  api 'commons-io:commons-io:2.7'
-  api "net.java.dev.jna:jna:5.10.0"
-  api 'gradle.plugin.com.github.johnrengelman:shadow:7.1.2'
-  api 'de.thetaphi:forbiddenapis:3.2'
-  api 'com.avast.gradle:gradle-docker-compose-plugin:0.14.12'
-  api 'org.apache.maven:maven-model:3.6.2'
-  api 'com.networknt:json-schema-validator:1.0.67'
-  api "com.fasterxml.jackson.core:jackson-databind:${props.getProperty('jackson')}"
+  api 'commons-codec:commons-codec:1.16.0'
+  api 'org.apache.commons:commons-compress:1.24.0'
+  api 'org.apache.ant:ant:1.10.13'
+  api 'com.netflix.nebula:gradle-extra-configurations-plugin:10.0.0'
+  api 'com.netflix.nebula:nebula-publishing-plugin:20.3.0'
+  api 'com.netflix.nebula:gradle-info-plugin:12.1.6'
+  api 'org.apache.rat:apache-rat:0.15'
+  api 'commons-io:commons-io:2.11.0'
+  api "net.java.dev.jna:jna:5.13.0"
+  api 'com.github.johnrengelman:shadow:8.1.1'
+  api 'org.jdom:jdom2:2.0.6.1'
+  api "org.jetbrains.kotlin:kotlin-stdlib-jdk8:${props.getProperty('kotlin')}"
+  api 'de.thetaphi:forbiddenapis:3.5.1'
+  api 'com.avast.gradle:gradle-docker-compose-plugin:0.16.11'
+  api "org.yaml:snakeyaml:${props.getProperty('snakeyaml')}"
+  api 'org.apache.maven:maven-model:3.9.4'
+  api 'com.networknt:json-schema-validator:1.0.86'
+  api 'org.jruby.jcodings:jcodings:1.0.58'
+  api 'org.jruby.joni:joni:2.2.1'
+  api "com.fasterxml.jackson.core:jackson-databind:${props.getProperty('jackson_databind')}"
+  api "org.ajoberstar.grgit:grgit-core:5.2.0"
 
   testFixturesApi "junit:junit:${props.getProperty('junit')}"
   testFixturesApi "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${props.getProperty('randomizedrunner')}"
   testFixturesApi gradleApi()
   testFixturesApi gradleTestKit()
-  testImplementation 'com.github.tomakehurst:wiremock-jre8-standalone:2.32.0'
+  testImplementation 'org.wiremock:wiremock-standalone:3.1.0'
   testImplementation "org.mockito:mockito-core:${props.getProperty('mockito')}"
-  integTestImplementation('org.spockframework:spock-core:2.1-groovy-3.0') {
+  integTestImplementation('org.spockframework:spock-core:2.3-groovy-3.0') {
     exclude module: "groovy"
   }
+  implementation('org.ajoberstar.grgit:grgit-core:5.2.0') {
+    exclude group: 'org.eclipse.jgit', module: 'org.eclipse.jgit'
+  }
+  implementation 'org.eclipse.jgit:org.eclipse.jgit:6.7.0.202309050840-r'
+}
+
+configurations.all {
+  resolutionStrategy {
+    force "com.google.guava:guava:${props.getProperty('guava')}"
+  }
 }
 
 /*****************************************************************************
@@ -158,8 +174,10 @@ if (project != rootProject) {
   apply plugin: 'opensearch.publish'
 
   allprojects {
-    targetCompatibility = JavaVersion.VERSION_11
-    sourceCompatibility = JavaVersion.VERSION_11
+    java {
+        targetCompatibility = JavaVersion.VERSION_11
+        sourceCompatibility = JavaVersion.VERSION_11
+    }
   }
 
   // groovydoc succeeds, but has some weird internal exception...
@@ -188,6 +206,7 @@ if (project != rootProject) {
     distribution project(':distribution:archives:linux-tar')
     distribution project(':distribution:archives:windows-zip')
 
+    integTestRuntimeOnly(project(":libs:opensearch-common"))
     integTestRuntimeOnly(project(":libs:opensearch-core"))
   }
 
diff --git a/buildSrc/reaper/build.gradle b/buildSrc/reaper/build.gradle
index d5e8d6ebc7099..58d06b02e9f4b 100644
--- a/buildSrc/reaper/build.gradle
+++ b/buildSrc/reaper/build.gradle
@@ -11,6 +11,11 @@
 
 apply plugin: 'java'
 
+java {
+  targetCompatibility = JavaVersion.VERSION_11
+  sourceCompatibility = JavaVersion.VERSION_11
+}
+
 jar {
   archiveFileName = "${project.name}.jar"
   manifest {
diff --git a/buildSrc/src/integTest/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTarIT.java b/buildSrc/src/integTest/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTarIT.java
index b70574c507f70..61aa55b9c6b53 100644
--- a/buildSrc/src/integTest/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTarIT.java
+++ b/buildSrc/src/integTest/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTarIT.java
@@ -35,6 +35,7 @@
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
 import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
 import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
+import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.test.GradleIntegrationTestCase;
 import org.gradle.api.GradleException;
 import org.gradle.testkit.runner.GradleRunner;
@@ -52,6 +53,7 @@
 
 import static org.hamcrest.CoreMatchers.anyOf;
 import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assume.assumeFalse;
 
 public class SymbolicLinkPreservingTarIT extends GradleIntegrationTestCase {
 
@@ -60,6 +62,7 @@ public class SymbolicLinkPreservingTarIT extends GradleIntegrationTestCase {
 
     @Before
     public void before() throws IOException {
+        assumeFalse("Skip tar tests on windows.", Os.isFamily(Os.FAMILY_WINDOWS));
         final Path realFolder = temporaryFolder.getRoot().toPath().resolve("real-folder");
         Files.createDirectory(realFolder);
         Files.createFile(realFolder.resolve("file"));
diff --git a/buildSrc/src/main/groovy/org/opensearch/gradle/CheckCompatibilityTask.groovy b/buildSrc/src/main/groovy/org/opensearch/gradle/CheckCompatibilityTask.groovy
new file mode 100644
index 0000000000000..cfd3d04ecd16c
--- /dev/null
+++ b/buildSrc/src/main/groovy/org/opensearch/gradle/CheckCompatibilityTask.groovy
@@ -0,0 +1,124 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle
+
+import groovy.json.JsonSlurper
+import org.ajoberstar.grgit.Grgit
+import org.ajoberstar.grgit.operation.BranchListOp
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.TaskAction
+import org.gradle.internal.os.OperatingSystem
+
+import java.nio.file.Paths
+
+class CheckCompatibilityTask extends DefaultTask {
+
+    static final String REPO_URL = 'https://raw.githubusercontent.com/opensearch-project/opensearch-plugins/main/plugins/.meta'
+
+    @Input
+    List repositoryUrls = project.hasProperty('repositoryUrls') ? project.property('repositoryUrls').split(',') : getRepoUrls()
+
+    @Input
+    String ref = project.hasProperty('ref') ? project.property('ref') : '2.x'
+
+    @Internal
+    List failedComponents = []
+
+    @Internal
+    List gitFailedComponents = []
+
+    @Internal
+    List compatibleComponents = []
+
+    @TaskAction
+    void checkCompatibility() {
+        repositoryUrls.parallelStream().forEach { repositoryUrl ->
+            logger.lifecycle("Checking compatibility for: $repositoryUrl with ref: $ref")
+            def tempDir = File.createTempDir()
+            def stdout = new ByteArrayOutputStream()
+            def errout = new ByteArrayOutputStream()
+            def skipped = false;
+            try {
+                if (cloneAndCheckout(repositoryUrl, tempDir)) {
+                    if (repositoryUrl.toString().endsWithAny('notifications', 'notifications.git')) {
+                        tempDir = Paths.get(tempDir.getAbsolutePath(), 'notifications')
+                    }
+                    project.exec {
+                        workingDir = tempDir
+                        executable = (OperatingSystem.current().isWindows()) ? 'gradlew.bat' : './gradlew'
+                        args ('assemble')
+                        standardOutput stdout
+                        errorOutput errout
+                    }
+                    compatibleComponents.add(repositoryUrl)
+                } else {
+                    skipped = true
+                }
+            } catch (ex) {
+                failedComponents.add(repositoryUrl)
+                logger.info("Gradle assemble failed for $repositoryUrl", ex)
+            } finally {
+                if (skipped) {
+                    logger.lifecycle("Skipping compatibility check for $repositoryUrl")
+                } else {
+                    logger.lifecycle("Finished compatibility check for $repositoryUrl")
+                    logger.info("Standard output for $repositoryUrl build:\n\n" + stdout.toString())
+                    logger.error("Error output for $repositoryUrl build:\n\n" + errout.toString())
+                }
+                tempDir.deleteDir()
+            }
+        }
+        if (!failedComponents.isEmpty()) {
+            logger.lifecycle("Incompatible components: $failedComponents")
+        }
+        if (!gitFailedComponents.isEmpty()) {
+            logger.lifecycle("Components skipped due to git failures: $gitFailedComponents")
+        }
+        if (!compatibleComponents.isEmpty()) {
+            logger.lifecycle("Compatible components: $compatibleComponents")
+        }
+    }
+
+    protected static List getRepoUrls() {
+        def json = new JsonSlurper().parse(REPO_URL.toURL())
+        def repository = json.projects.values()
+        def repoUrls = replaceSshWithHttps(repository as List)
+        return repoUrls
+    }
+
+    protected static replaceSshWithHttps(List<String> repoList) {
+        repoList.replaceAll { element ->
+            element.replace("git@github.com:", "https://github.com/")
+        }
+        return repoList
+    }
+
+    protected boolean cloneAndCheckout(repoUrl, directory) {
+        try {
+            def grgit = Grgit.clone(dir: directory, uri: repoUrl)
+            def remoteBranches = grgit.branch.list(mode: BranchListOp.Mode.REMOTE)
+            String targetBranch = 'origin/' + ref
+            if (remoteBranches.find { it.name == targetBranch } == null) {
+                gitFailedComponents.add(repoUrl)
+                logger.info("$ref does not exist for $repoUrl. Skipping the compatibility check!!")
+                return false
+            } else {
+                logger.info("Checking out $targetBranch")
+                grgit.checkout(branch: targetBranch)
+                return true
+            }
+        } catch (ex) {
+            logger.error('Exception occurred during GitHub operations', ex)
+            gitFailedComponents.add(repoUrl)
+            return false
+        }
+    }
+}
diff --git a/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/OptionalDependenciesPlugin.groovy b/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/OptionalDependenciesPlugin.groovy
new file mode 100644
index 0000000000000..2bd8835535881
--- /dev/null
+++ b/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/OptionalDependenciesPlugin.groovy
@@ -0,0 +1,124 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+/*
+ * Copyright 2014-2016 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.opensearch.gradle.plugin
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.publish.ivy.IvyPublication
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.publish.plugins.PublishingPlugin
+
+/**
+ * Including the support of `optional` dependencies: https://github.com/nebula-plugins/gradle-extra-configurations-plugin/blob/v9.0.0/src/main/groovy/nebula/plugin/extraconfigurations/OptionalBasePlugin.groovy
+ */
+class OptionalDependenciesPlugin implements Plugin<Project> {
+    static final String OPTIONAL_IDENTIFIER = 'optional'
+
+    @Override
+    void apply(Project project) {
+        enhanceProjectModel(project)
+        configureMavenPublishPlugin(project)
+        configureIvyPublishPlugin(project)
+    }
+
+    /**
+     * Enhances the Project domain object by adding
+     *
+     * a) a extra property List that holds optional dependencies
+     * b) a extra method that can be executed as parameter when declaring dependencies
+     *
+     * @param project Project
+     */
+    private void enhanceProjectModel(Project project) {
+        project.ext.optionalDeps = []
+
+        project.ext.optional = { dep ->
+            project.ext.optionalDeps << dep
+        }
+    }
+
+    /**
+     * Configures Maven Publishing plugin to ensure that published dependencies receive the optional element.
+     *
+     * @param project Project
+     */
+    private void configureMavenPublishPlugin(Project project) {
+        project.plugins.withType(PublishingPlugin) {
+            project.publishing {
+                publications {
+                    project.extensions.findByType(PublishingExtension)?.publications?.withType(MavenPublication) { MavenPublication pub ->
+                        pub.pom.withXml {
+                            project.ext.optionalDeps.each { dep ->
+                                def foundDep = asNode().dependencies.dependency.find {
+                                    it.groupId.text() == dep.group && it.artifactId.text() == dep.name
+                                }
+
+                                if (foundDep) {
+                                    if (foundDep.optional) {
+                                        foundDep.optional.value = 'true'
+                                    } else {
+                                        foundDep.appendNode(OPTIONAL_IDENTIFIER, 'true')
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Configures Ivy Publishing plugin to ensure that published dependencies receive the correct conf attribute value.
+     *
+     * @param project Project
+     */
+    private void configureIvyPublishPlugin(Project project) {
+        project.plugins.withType(PublishingPlugin) {
+            project.publishing {
+                publications {
+                    project.extensions.findByType(PublishingExtension)?.publications?.withType(IvyPublication) { IvyPublication pub ->
+                        pub.descriptor.withXml {
+                            def rootNode = asNode()
+
+                            // Add optional configuration if it doesn't exist yet
+                            if (!rootNode.configurations.find { it.@name == OPTIONAL_IDENTIFIER }) {
+                                rootNode.configurations[0].appendNode('conf', [name: OPTIONAL_IDENTIFIER, visibility: 'public'])
+                            }
+
+                            // Replace dependency "runtime->default" conf attribute value with "optional"
+                            project.ext.optionalDeps.each { dep ->
+                                def foundDep = rootNode.dependencies.dependency.find { it.@name == dep.name }
+                                foundDep?.@conf = OPTIONAL_IDENTIFIER
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/PluginBuildPlugin.groovy b/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/PluginBuildPlugin.groovy
index 31677965ab0d3..556763333d279 100644
--- a/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/PluginBuildPlugin.groovy
+++ b/buildSrc/src/main/groovy/org/opensearch/gradle/plugin/PluginBuildPlugin.groovy
@@ -29,13 +29,13 @@
 package org.opensearch.gradle.plugin
 
 import com.github.jengelman.gradle.plugins.shadow.ShadowPlugin
+import org.gradle.api.tasks.bundling.AbstractArchiveTask
 import org.opensearch.gradle.BuildPlugin
 import org.opensearch.gradle.NoticeTask
 import org.opensearch.gradle.Version
 import org.opensearch.gradle.VersionProperties
 import org.opensearch.gradle.dependencies.CompileOnlyResolvePlugin
 import org.opensearch.gradle.info.BuildParams
-import org.opensearch.gradle.plugin.PluginPropertiesExtension
 import org.opensearch.gradle.test.RestTestBasePlugin
 import org.opensearch.gradle.testclusters.RunTask
 import org.opensearch.gradle.util.Util
@@ -44,6 +44,8 @@ import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.api.plugins.BasePlugin
+import org.gradle.api.plugins.BasePluginExtension
+import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.api.publish.maven.MavenPublication
 import org.gradle.api.publish.maven.plugins.MavenPublishPlugin
 import org.gradle.api.publish.maven.tasks.GenerateMavenPom
@@ -85,7 +87,9 @@ class PluginBuildPlugin implements Plugin<Project> {
             PluginPropertiesExtension extension1 = project.getExtensions().getByType(PluginPropertiesExtension.class)
             configurePublishing(project, extension1)
             String name = extension1.name
-            project.archivesBaseName = name
+
+            BasePluginExtension base = project.getExtensions().findByType(BasePluginExtension.class)
+            base.archivesBaseName = name
             project.description = extension1.description
 
             if (extension1.name == null) {
@@ -98,12 +102,13 @@ class PluginBuildPlugin implements Plugin<Project> {
                 throw new InvalidUserDataException('classname is a required setting for opensearchplugin')
             }
 
+            JavaPluginExtension java = project.getExtensions().findByType(JavaPluginExtension.class)
             Map<String, String> properties = [
                     'name'                : extension1.name,
                     'description'         : extension1.description,
                     'version'             : extension1.version,
                     'opensearchVersion'   : Version.fromString(VersionProperties.getOpenSearch()).toString(),
-                    'javaVersion'         : project.targetCompatibility as String,
+                    'javaVersion'         : java.targetCompatibility as String,
                     'classname'           : extension1.classname,
                     'customFolderName'    : extension1.customFolderName,
                     'extendedPlugins'     : extension1.extendedPlugins.join(','),
@@ -134,6 +139,12 @@ class PluginBuildPlugin implements Plugin<Project> {
         }
         project.configurations.getByName('default')
                 .extendsFrom(project.configurations.getByName('runtimeClasspath'))
+        project.tasks.withType(AbstractArchiveTask.class).configureEach { task ->
+            // ignore file timestamps
+            // be consistent in archive file order
+            task.preserveFileTimestamps = false
+            task.reproducibleFileOrder = true
+        }
         // allow running ES with this plugin in the foreground of a build
         project.tasks.register('run', RunTask) {
             dependsOn(project.tasks.bundlePlugin)
@@ -143,15 +154,16 @@ class PluginBuildPlugin implements Plugin<Project> {
     private void configurePublishing(Project project, PluginPropertiesExtension extension) {
         // Only configure publishing if applied externally
         if (extension.hasClientJar) {
-            project.pluginManager.apply('nebula.maven-base-publish')
+            project.pluginManager.apply('com.netflix.nebula.maven-base-publish')
             // Only change Jar tasks, we don't want a -client zip so we can't change archivesBaseName
             project.tasks.withType(Jar) {
                 archiveBaseName = archiveBaseName.get() +  "-client"
             }
             // always configure publishing for client jars
             project.publishing.publications.nebula(MavenPublication).artifactId(extension.name + "-client")
+            final BasePluginExtension base = project.getExtensions().findByType(BasePluginExtension.class)
             project.tasks.withType(GenerateMavenPom.class).configureEach { GenerateMavenPom generatePOMTask ->
-                generatePOMTask.destination = "${project.buildDir}/distributions/${project.archivesBaseName}-client-${project.versions.opensearch}.pom"
+                generatePOMTask.destination = "${project.buildDir}/distributions/${base.archivesBaseName}-client-${project.versions.opensearch}.pom"
             }
         } else {
             if (project.plugins.hasPlugin(MavenPublishPlugin)) {
diff --git a/buildSrc/src/main/groovy/org/opensearch/gradle/precommit/LicenseHeadersTask.groovy b/buildSrc/src/main/groovy/org/opensearch/gradle/precommit/LicenseHeadersTask.groovy
index b330934ed2d26..b8d0ed2b9c43c 100644
--- a/buildSrc/src/main/groovy/org/opensearch/gradle/precommit/LicenseHeadersTask.groovy
+++ b/buildSrc/src/main/groovy/org/opensearch/gradle/precommit/LicenseHeadersTask.groovy
@@ -35,7 +35,10 @@ import org.opensearch.gradle.AntTask
 import org.gradle.api.file.FileCollection
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.SkipWhenEmpty
 
 import java.nio.file.Files
@@ -78,6 +81,8 @@ class LicenseHeadersTask extends AntTask {
      */
     @InputFiles
     @SkipWhenEmpty
+    @IgnoreEmptyDirectories
+    @PathSensitive(PathSensitivity.RELATIVE)
     List<FileCollection> getJavaFiles() {
         return project.sourceSets.collect({it.allJava})
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/Architecture.java b/buildSrc/src/main/java/org/opensearch/gradle/Architecture.java
index 38d6db8c9916e..b16f35a9ad0eb 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/Architecture.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/Architecture.java
@@ -35,7 +35,9 @@
 public enum Architecture {
 
     X64,
-    ARM64;
+    ARM64,
+    S390X,
+    PPC64LE;
 
     public static Architecture current() {
         final String architecture = System.getProperty("os.arch", "");
@@ -45,6 +47,10 @@ public static Architecture current() {
                 return X64;
             case "aarch64":
                 return ARM64;
+            case "s390x":
+                return S390X;
+            case "ppc64le":
+                return PPC64LE;
             default:
                 throw new IllegalArgumentException("can not determine architecture from [" + architecture + "]");
         }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/ConcatFilesTask.java b/buildSrc/src/main/java/org/opensearch/gradle/ConcatFilesTask.java
index 96e3702d5a729..e5cd767ba0e67 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/ConcatFilesTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/ConcatFilesTask.java
@@ -31,6 +31,14 @@
 
 package org.opensearch.gradle;
 
+import org.gradle.api.DefaultTask;
+import org.gradle.api.file.FileTree;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.InputFiles;
+import org.gradle.api.tasks.Optional;
+import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.TaskAction;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -40,14 +48,6 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 
-import org.gradle.api.DefaultTask;
-import org.gradle.api.file.FileTree;
-import org.gradle.api.tasks.Input;
-import org.gradle.api.tasks.InputFiles;
-import org.gradle.api.tasks.Optional;
-import org.gradle.api.tasks.OutputFile;
-import org.gradle.api.tasks.TaskAction;
-
 /**
  * Concatenates a list of files into one and removes duplicate lines.
  */
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java
index fccdc49ef6fc9..7b6aa6774b401 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java
@@ -80,6 +80,8 @@ public class DistributionDownloadPlugin implements Plugin<Project> {
     private static final String RELEASE_PATTERN_LAYOUT = "/core/opensearch/[revision]/[module]-min-[revision](-[classifier]).[ext]";
     private static final String SNAPSHOT_PATTERN_LAYOUT =
         "/snapshots/core/opensearch/[revision]/[module]-min-[revision](-[classifier])-latest.[ext]";
+    private static final String BUNDLE_PATTERN_LAYOUT =
+        "/ci/dbc/distribution-build-opensearch/[revision]/latest/linux/x64/tar/dist/opensearch/[module]-[revision](-[classifier]).[ext]";
 
     private NamedDomainObjectContainer<OpenSearchDistribution> distributionsContainer;
     private NamedDomainObjectContainer<DistributionResolution> distributionsResolutionStrategiesContainer;
@@ -196,24 +198,45 @@ private static void setupDownloadServiceRepo(Project project) {
             return;
         }
         Object customDistributionUrl = project.findProperty("customDistributionUrl");
-        // checks if custom Distribution Url has been passed by user from plugins
+        Object customDistributionDownloadType = project.findProperty("customDistributionDownloadType");
+        // distributionDownloadType is default min if is not specified; download the distribution from CI if is bundle
+        String distributionDownloadType = customDistributionDownloadType != null
+            && customDistributionDownloadType.toString().equals("bundle") ? "bundle" : "min";
+
+        addIvyRepo2(project, DOWNLOAD_REPO_NAME_ES, "https://artifacts-no-kpi.elastic.co", FAKE_IVY_GROUP_ES);
+        addIvyRepo2(project, SNAPSHOT_REPO_NAME_ES, "https://snapshots-no-kpi.elastic.co", FAKE_SNAPSHOT_IVY_GROUP_ES);
+
         if (customDistributionUrl != null) {
             addIvyRepo(project, DOWNLOAD_REPO_NAME, customDistributionUrl.toString(), FAKE_IVY_GROUP, "");
             addIvyRepo(project, SNAPSHOT_REPO_NAME, customDistributionUrl.toString(), FAKE_SNAPSHOT_IVY_GROUP, "");
-        } else {
-            addIvyRepo(
-                project,
-                DOWNLOAD_REPO_NAME,
-                "https://artifacts.opensearch.org",
-                FAKE_IVY_GROUP,
-                "/releases" + RELEASE_PATTERN_LAYOUT,
-                "/release-candidates" + RELEASE_PATTERN_LAYOUT
-            );
-            addIvyRepo(project, SNAPSHOT_REPO_NAME, "https://artifacts.opensearch.org", FAKE_SNAPSHOT_IVY_GROUP, SNAPSHOT_PATTERN_LAYOUT);
+            return;
+        }
+        switch (distributionDownloadType) {
+            case "bundle":
+                addIvyRepo(project, DOWNLOAD_REPO_NAME, "https://ci.opensearch.org", FAKE_IVY_GROUP, BUNDLE_PATTERN_LAYOUT);
+                addIvyRepo(project, SNAPSHOT_REPO_NAME, "https://ci.opensearch.org", FAKE_SNAPSHOT_IVY_GROUP, BUNDLE_PATTERN_LAYOUT);
+                break;
+            case "min":
+                addIvyRepo(
+                    project,
+                    DOWNLOAD_REPO_NAME,
+                    "https://artifacts.opensearch.org",
+                    FAKE_IVY_GROUP,
+                    "/releases" + RELEASE_PATTERN_LAYOUT,
+                    "/release-candidates" + RELEASE_PATTERN_LAYOUT
+                );
+                addIvyRepo(
+                    project,
+                    SNAPSHOT_REPO_NAME,
+                    "https://artifacts.opensearch.org",
+                    FAKE_SNAPSHOT_IVY_GROUP,
+                    SNAPSHOT_PATTERN_LAYOUT
+                );
+                break;
+            default:
+                throw new IllegalArgumentException("Unsupported property argument: " + distributionDownloadType);
         }
 
-        addIvyRepo2(project, DOWNLOAD_REPO_NAME_ES, "https://artifacts-no-kpi.elastic.co", FAKE_IVY_GROUP_ES);
-        addIvyRepo2(project, SNAPSHOT_REPO_NAME_ES, "https://snapshots-no-kpi.elastic.co", FAKE_SNAPSHOT_IVY_GROUP_ES);
     }
 
     /**
@@ -247,6 +270,12 @@ private String dependencyNotation(OpenSearchDistribution distribution) {
                     case X64:
                         classifier = ":" + distribution.getPlatform() + "-x64";
                         break;
+                    case S390X:
+                        classifier = ":" + distribution.getPlatform() + "-s390x";
+                        break;
+                    case PPC64LE:
+                        classifier = ":" + distribution.getPlatform() + "-ppc64le";
+                        break;
                     default:
                         throw new IllegalArgumentException("Unsupported architecture: " + distribution.getArchitecture());
                 }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/EmptyDirTask.java b/buildSrc/src/main/java/org/opensearch/gradle/EmptyDirTask.java
index f16b667f96ed4..96d7c69699c68 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/EmptyDirTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/EmptyDirTask.java
@@ -31,16 +31,16 @@
 
 package org.opensearch.gradle;
 
-import java.io.File;
-
-import javax.inject.Inject;
-
 import org.gradle.api.DefaultTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.internal.file.Chmod;
 
+import javax.inject.Inject;
+
+import java.io.File;
+
 /**
  * Creates an empty directory.
  */
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/JavaPackageType.java b/buildSrc/src/main/java/org/opensearch/gradle/JavaPackageType.java
new file mode 100644
index 0000000000000..2acc335d80df0
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/JavaPackageType.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle;
+
+public enum JavaPackageType {
+    NONE,
+    JRE,
+    JDK
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/JavaVariant.java b/buildSrc/src/main/java/org/opensearch/gradle/JavaVariant.java
new file mode 100644
index 0000000000000..5f576984627a8
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/JavaVariant.java
@@ -0,0 +1,197 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle;
+
+import org.gradle.api.Buildable;
+import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.model.ObjectFactory;
+import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.TaskDependency;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+abstract class JavaVariant implements Buildable, Iterable<File> {
+
+    private static final List<String> ALLOWED_ARCHITECTURES = Collections.unmodifiableList(
+        Arrays.asList("aarch64", "x64", "s390x", "ppc64le")
+    );
+    private static final List<String> ALLOWED_VENDORS = Collections.unmodifiableList(Arrays.asList("adoptium", "adoptopenjdk", "openjdk"));
+    private static final List<String> ALLOWED_PLATFORMS = Collections.unmodifiableList(
+        Arrays.asList("darwin", "freebsd", "linux", "mac", "windows")
+    );
+    private static final Pattern VERSION_PATTERN = Pattern.compile("(\\d+)(\\.\\d+\\.\\d+)?\\+(\\d+(?:\\.\\d+)?)(@([a-f0-9]{32}))?");
+    private static final Pattern LEGACY_VERSION_PATTERN = Pattern.compile("(\\d)(u\\d+)(?:\\+|\\-)(b\\d+?)(@([a-f0-9]{32}))?");
+
+    private final String name;
+    private final Configuration configuration;
+
+    private final Property<String> vendor;
+    private final Property<String> version;
+    private final Property<String> platform;
+    private final Property<String> architecture;
+    private String baseVersion;
+    private String major;
+    private String build;
+    private String hash;
+
+    JavaVariant(String name, Configuration configuration, ObjectFactory objectFactory) {
+        this.name = name;
+        this.configuration = configuration;
+        this.vendor = objectFactory.property(String.class);
+        this.version = objectFactory.property(String.class);
+        this.platform = objectFactory.property(String.class);
+        this.architecture = objectFactory.property(String.class);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getVendor() {
+        return vendor.get();
+    }
+
+    public void setVendor(final String vendor) {
+        if (ALLOWED_VENDORS.contains(vendor) == false) {
+            throw new IllegalArgumentException("unknown vendor [" + vendor + "] for jdk [" + name + "], must be one of " + ALLOWED_VENDORS);
+        }
+        this.vendor.set(vendor);
+    }
+
+    public String getVersion() {
+        return version.get();
+    }
+
+    public void setVersion(String version) {
+        if (VERSION_PATTERN.matcher(version).matches() == false && LEGACY_VERSION_PATTERN.matcher(version).matches() == false) {
+            throw new IllegalArgumentException("malformed version [" + version + "] for jdk [" + name + "]");
+        }
+        parseVersion(version);
+        this.version.set(version);
+    }
+
+    public String getPlatform() {
+        return platform.get();
+    }
+
+    public void setPlatform(String platform) {
+        if (ALLOWED_PLATFORMS.contains(platform) == false) {
+            throw new IllegalArgumentException(
+                "unknown platform [" + platform + "] for jdk [" + name + "], must be one of " + ALLOWED_PLATFORMS
+            );
+        }
+        this.platform.set(platform);
+    }
+
+    public String getArchitecture() {
+        return architecture.get();
+    }
+
+    public void setArchitecture(final String architecture) {
+        String jdkArchitecture = translateJdkArchitecture(architecture);
+        if (ALLOWED_ARCHITECTURES.contains(jdkArchitecture) == false) {
+            throw new IllegalArgumentException(
+                "unknown architecture [" + jdkArchitecture + "] for jdk [" + name + "], must be one of " + ALLOWED_ARCHITECTURES
+            );
+        }
+        this.architecture.set(jdkArchitecture);
+    }
+
+    public String getBaseVersion() {
+        return baseVersion;
+    }
+
+    public String getMajor() {
+        return major;
+    }
+
+    public String getBuild() {
+        return build;
+    }
+
+    public String getHash() {
+        return hash;
+    }
+
+    public String getPath() {
+        return configuration.getSingleFile().toString();
+    }
+
+    public String getConfigurationName() {
+        return configuration.getName();
+    }
+
+    @Override
+    public String toString() {
+        return getPath();
+    }
+
+    @Override
+    public TaskDependency getBuildDependencies() {
+        return configuration.getBuildDependencies();
+    }
+
+    // internal, make this jdks configuration unmodifiable
+    void finalizeValues() {
+        if (version.isPresent() == false) {
+            throw new IllegalArgumentException("version not specified for jdk [" + name + "]");
+        }
+        if (platform.isPresent() == false) {
+            throw new IllegalArgumentException("platform not specified for jdk [" + name + "]");
+        }
+        if (vendor.isPresent() == false) {
+            throw new IllegalArgumentException("vendor not specified for jdk [" + name + "]");
+        }
+        if (architecture.isPresent() == false) {
+            throw new IllegalArgumentException("architecture not specified for jdk [" + name + "]");
+        }
+        version.finalizeValue();
+        platform.finalizeValue();
+        vendor.finalizeValue();
+        architecture.finalizeValue();
+    }
+
+    @Override
+    public Iterator<File> iterator() {
+        return configuration.iterator();
+    }
+
+    private void parseVersion(String version) {
+        // decompose the bundled jdk version, broken into elements as: [feature, interim, update, build]
+        // Note the "patch" version is not yet handled here, as it has not yet been used by java.
+        Matcher jdkVersionMatcher = VERSION_PATTERN.matcher(version);
+        if (jdkVersionMatcher.matches() == false) {
+            // Try again with the pre-Java9 version format
+            jdkVersionMatcher = LEGACY_VERSION_PATTERN.matcher(version);
+
+            if (jdkVersionMatcher.matches() == false) {
+                throw new IllegalArgumentException("Malformed jdk version [" + version + "]");
+            }
+        }
+
+        baseVersion = jdkVersionMatcher.group(1) + (jdkVersionMatcher.group(2) != null ? (jdkVersionMatcher.group(2)) : "");
+        major = jdkVersionMatcher.group(1);
+        build = jdkVersionMatcher.group(3);
+        hash = jdkVersionMatcher.group(5);
+    }
+
+    private String translateJdkArchitecture(String architecture) {
+        /*
+         * Jdk uses aarch64 from ARM. Translating from arm64 to aarch64 which Jdk understands.
+         */
+        return "arm64".equals(architecture) ? "aarch64" : architecture;
+    }
+
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/Jdk.java b/buildSrc/src/main/java/org/opensearch/gradle/Jdk.java
index 792debe3f350a..3218abe726639 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/Jdk.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/Jdk.java
@@ -32,144 +32,20 @@
 
 package org.opensearch.gradle;
 
-import org.gradle.api.Buildable;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.model.ObjectFactory;
-import org.gradle.api.provider.Property;
-import org.gradle.api.tasks.TaskDependency;
-
-import java.io.File;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-public class Jdk implements Buildable, Iterable<File> {
-
-    private static final List<String> ALLOWED_ARCHITECTURES = Collections.unmodifiableList(Arrays.asList("aarch64", "x64"));
-    private static final List<String> ALLOWED_VENDORS = Collections.unmodifiableList(Arrays.asList("adoptium", "adoptopenjdk", "openjdk"));
-    private static final List<String> ALLOWED_PLATFORMS = Collections.unmodifiableList(
-        Arrays.asList("darwin", "freebsd", "linux", "mac", "windows")
-    );
-    private static final Pattern VERSION_PATTERN = Pattern.compile("(\\d+)(\\.\\d+\\.\\d+)?\\+(\\d+(?:\\.\\d+)?)(@([a-f0-9]{32}))?");
-    private static final Pattern LEGACY_VERSION_PATTERN = Pattern.compile("(\\d)(u\\d+)\\+(b\\d+?)(@([a-f0-9]{32}))?");
-
-    private final String name;
-    private final Configuration configuration;
-
-    private final Property<String> vendor;
-    private final Property<String> version;
-    private final Property<String> platform;
-    private final Property<String> architecture;
-    private String baseVersion;
-    private String major;
-    private String build;
-    private String hash;
+import org.gradle.internal.os.OperatingSystem;
 
+public class Jdk extends JavaVariant {
     Jdk(String name, Configuration configuration, ObjectFactory objectFactory) {
-        this.name = name;
-        this.configuration = configuration;
-        this.vendor = objectFactory.property(String.class);
-        this.version = objectFactory.property(String.class);
-        this.platform = objectFactory.property(String.class);
-        this.architecture = objectFactory.property(String.class);
-    }
-
-    public String getName() {
-        return name;
-    }
-
-    public String getVendor() {
-        return vendor.get();
-    }
-
-    public void setVendor(final String vendor) {
-        if (ALLOWED_VENDORS.contains(vendor) == false) {
-            throw new IllegalArgumentException("unknown vendor [" + vendor + "] for jdk [" + name + "], must be one of " + ALLOWED_VENDORS);
-        }
-        this.vendor.set(vendor);
-    }
-
-    public String getVersion() {
-        return version.get();
-    }
-
-    public void setVersion(String version) {
-        if (VERSION_PATTERN.matcher(version).matches() == false && LEGACY_VERSION_PATTERN.matcher(version).matches() == false) {
-            throw new IllegalArgumentException("malformed version [" + version + "] for jdk [" + name + "]");
-        }
-        parseVersion(version);
-        this.version.set(version);
-    }
-
-    public String getPlatform() {
-        return platform.get();
-    }
-
-    public void setPlatform(String platform) {
-        if (ALLOWED_PLATFORMS.contains(platform) == false) {
-            throw new IllegalArgumentException(
-                "unknown platform [" + platform + "] for jdk [" + name + "], must be one of " + ALLOWED_PLATFORMS
-            );
-        }
-        this.platform.set(platform);
-    }
-
-    public String getArchitecture() {
-        return architecture.get();
-    }
-
-    public void setArchitecture(final String architecture) {
-        String jdkArchitecture = translateJdkArchitecture(architecture);
-        if (ALLOWED_ARCHITECTURES.contains(jdkArchitecture) == false) {
-            throw new IllegalArgumentException(
-                "unknown architecture [" + jdkArchitecture + "] for jdk [" + name + "], must be one of " + ALLOWED_ARCHITECTURES
-            );
-        }
-        this.architecture.set(architecture);
-    }
-
-    public String getBaseVersion() {
-        return baseVersion;
-    }
-
-    public String getMajor() {
-        return major;
-    }
-
-    public String getBuild() {
-        return build;
-    }
-
-    public String getHash() {
-        return hash;
-    }
-
-    public String getPath() {
-        return configuration.getSingleFile().toString();
-    }
-
-    public String getConfigurationName() {
-        return configuration.getName();
-    }
-
-    @Override
-    public String toString() {
-        return getPath();
-    }
-
-    @Override
-    public TaskDependency getBuildDependencies() {
-        return configuration.getBuildDependencies();
+        super(name, configuration, objectFactory);
     }
 
     public Object getBinJavaPath() {
         return new Object() {
             @Override
             public String toString() {
-                return getHomeRoot() + "/bin/java";
+                return OperatingSystem.current().getExecutableName(getHomeRoot() + "/bin/java");
             }
         };
     }
@@ -187,56 +63,4 @@ private String getHomeRoot() {
         boolean isOSX = "mac".equals(getPlatform()) || "darwin".equals(getPlatform());
         return getPath() + (isOSX ? "/Contents/Home" : "");
     }
-
-    // internal, make this jdks configuration unmodifiable
-    void finalizeValues() {
-        if (version.isPresent() == false) {
-            throw new IllegalArgumentException("version not specified for jdk [" + name + "]");
-        }
-        if (platform.isPresent() == false) {
-            throw new IllegalArgumentException("platform not specified for jdk [" + name + "]");
-        }
-        if (vendor.isPresent() == false) {
-            throw new IllegalArgumentException("vendor not specified for jdk [" + name + "]");
-        }
-        if (architecture.isPresent() == false) {
-            throw new IllegalArgumentException("architecture not specified for jdk [" + name + "]");
-        }
-        version.finalizeValue();
-        platform.finalizeValue();
-        vendor.finalizeValue();
-        architecture.finalizeValue();
-    }
-
-    @Override
-    public Iterator<File> iterator() {
-        return configuration.iterator();
-    }
-
-    private void parseVersion(String version) {
-        // decompose the bundled jdk version, broken into elements as: [feature, interim, update, build]
-        // Note the "patch" version is not yet handled here, as it has not yet been used by java.
-        Matcher jdkVersionMatcher = VERSION_PATTERN.matcher(version);
-        if (jdkVersionMatcher.matches() == false) {
-            // Try again with the pre-Java9 version format
-            jdkVersionMatcher = LEGACY_VERSION_PATTERN.matcher(version);
-
-            if (jdkVersionMatcher.matches() == false) {
-                throw new IllegalArgumentException("Malformed jdk version [" + version + "]");
-            }
-        }
-
-        baseVersion = jdkVersionMatcher.group(1) + (jdkVersionMatcher.group(2) != null ? (jdkVersionMatcher.group(2)) : "");
-        major = jdkVersionMatcher.group(1);
-        build = jdkVersionMatcher.group(3);
-        hash = jdkVersionMatcher.group(5);
-    }
-
-    private String translateJdkArchitecture(String architecture) {
-        /*
-         * Jdk uses aarch64 from ARM. Translating from arm64 to aarch64 which Jdk understands.
-         */
-        return "arm64".equals(architecture) ? "aarch64" : architecture;
-    }
-
 }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/JdkDownloadPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/JdkDownloadPlugin.java
index b9f3036f7aad9..c359e3a497049 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/JdkDownloadPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/JdkDownloadPlugin.java
@@ -110,22 +110,34 @@ private void setupRepository(Project project, Jdk jdk) {
 
         if (jdk.getVendor().equals(VENDOR_ADOPTIUM)) {
             repoUrl = "https://github.com/adoptium/temurin" + jdk.getMajor() + "-binaries/releases/download/";
-            // JDK updates are suffixed with 'U' (fe OpenJDK17U), whereas GA releases are not (fe OpenJDK17).
-            // To distinguish between those, the GA releases have only major version component (fe 17+32),
-            // the updates always have minor/patch components (fe 17.0.1+12), checking for the presence of
-            // version separator '.' should be enough.
-            artifactPattern = "jdk-"
-                + jdk.getBaseVersion()
-                + "+"
-                + jdk.getBuild()
-                + "/OpenJDK"
-                + jdk.getMajor()
-                + (jdk.getBaseVersion().contains(".") ? "U" : "")
-                + "-jdk_[classifier]_[module]_hotspot_"
-                + jdk.getBaseVersion()
-                + "_"
-                + jdk.getBuild()
-                + ".[ext]";
+
+            if (jdk.getMajor().equals("8")) {
+                // JDK-8 updates are always suffixed with 'U' (fe OpenJDK8U).
+                artifactPattern = "jdk"
+                    + jdk.getBaseVersion()
+                    + "-"
+                    + jdk.getBuild()
+                    + "/OpenJDK"
+                    + jdk.getMajor()
+                    + "U"
+                    + "-jdk_[classifier]_[module]_hotspot_"
+                    + jdk.getBaseVersion()
+                    + jdk.getBuild()
+                    + ".[ext]";
+            } else {
+                // JDK updates are suffixed with 'U' (fe OpenJDK17U), whereas GA releases are not (fe OpenJDK17).
+                // To distinguish between those, the GA releases have only major version component (fe 17+32),
+                // the updates always have minor/patch components (fe 17.0.1+12), checking for the presence of
+                // version separator '.' should be enough.
+                artifactPattern = "jdk-" + jdk.getBaseVersion() + "+" + jdk.getBuild() + "/OpenJDK" + jdk.getMajor()
+                // JDK-20 does use 'U' suffix all the time, no matter it is update or GA release
+                    + (jdk.getBaseVersion().contains(".") || jdk.getBaseVersion().matches("^2\\d+$") ? "U" : "")
+                    + "-jdk_[classifier]_[module]_hotspot_"
+                    + jdk.getBaseVersion()
+                    + "_"
+                    + jdk.getBuild()
+                    + ".[ext]";
+            }
         } else if (jdk.getVendor().equals(VENDOR_ADOPTOPENJDK)) {
             repoUrl = "https://api.adoptopenjdk.net/v3/binary/version/";
             if (jdk.getMajor().equals("8")) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/Jre.java b/buildSrc/src/main/java/org/opensearch/gradle/Jre.java
new file mode 100644
index 0000000000000..473bfc4860b80
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/Jre.java
@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle;
+
+import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.model.ObjectFactory;
+
+public class Jre extends JavaVariant {
+    Jre(String name, Configuration configuration, ObjectFactory objectFactory) {
+        super(name, configuration, objectFactory);
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/JreDownloadPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/JreDownloadPlugin.java
new file mode 100644
index 0000000000000..5a00f41f07a60
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/JreDownloadPlugin.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle;
+
+import org.opensearch.gradle.transform.SymbolicLinkPreservingUntarTransform;
+import org.opensearch.gradle.transform.UnzipTransform;
+import org.gradle.api.GradleException;
+import org.gradle.api.NamedDomainObjectContainer;
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.artifacts.dsl.RepositoryHandler;
+import org.gradle.api.artifacts.repositories.IvyArtifactRepository;
+import org.gradle.api.artifacts.type.ArtifactTypeDefinition;
+import org.gradle.api.attributes.Attribute;
+import org.gradle.api.internal.artifacts.ArtifactAttributes;
+
+public class JreDownloadPlugin implements Plugin<Project> {
+    public static final String VENDOR_ADOPTIUM = "adoptium";
+
+    private static final String REPO_NAME_PREFIX = "jre_repo_";
+    private static final String EXTENSION_NAME = "jres";
+    public static final String JRE_TRIMMED_PREFIX = "jdk-?\\d.*-jre";
+
+    @Override
+    public void apply(Project project) {
+        Attribute<Boolean> jreAttribute = Attribute.of("jre", Boolean.class);
+        project.getDependencies().getAttributesSchema().attribute(jreAttribute);
+        project.getDependencies().getArtifactTypes().maybeCreate(ArtifactTypeDefinition.ZIP_TYPE);
+        project.getDependencies().registerTransform(UnzipTransform.class, transformSpec -> {
+            transformSpec.getFrom()
+                .attribute(ArtifactAttributes.ARTIFACT_FORMAT, ArtifactTypeDefinition.ZIP_TYPE)
+                .attribute(jreAttribute, true);
+            transformSpec.getTo()
+                .attribute(ArtifactAttributes.ARTIFACT_FORMAT, ArtifactTypeDefinition.DIRECTORY_TYPE)
+                .attribute(jreAttribute, true);
+            transformSpec.parameters(parameters -> parameters.setTrimmedPrefixPattern(JRE_TRIMMED_PREFIX));
+        });
+
+        ArtifactTypeDefinition tarArtifactTypeDefinition = project.getDependencies().getArtifactTypes().maybeCreate("tar.gz");
+        project.getDependencies().registerTransform(SymbolicLinkPreservingUntarTransform.class, transformSpec -> {
+            transformSpec.getFrom()
+                .attribute(ArtifactAttributes.ARTIFACT_FORMAT, tarArtifactTypeDefinition.getName())
+                .attribute(jreAttribute, true);
+            transformSpec.getTo()
+                .attribute(ArtifactAttributes.ARTIFACT_FORMAT, ArtifactTypeDefinition.DIRECTORY_TYPE)
+                .attribute(jreAttribute, true);
+            transformSpec.parameters(parameters -> parameters.setTrimmedPrefixPattern(JRE_TRIMMED_PREFIX));
+        });
+
+        NamedDomainObjectContainer<Jre> jresContainer = project.container(Jre.class, name -> {
+            Configuration configuration = project.getConfigurations().create("jre_" + name);
+            configuration.setCanBeConsumed(false);
+            configuration.getAttributes().attribute(ArtifactAttributes.ARTIFACT_FORMAT, ArtifactTypeDefinition.DIRECTORY_TYPE);
+            configuration.getAttributes().attribute(jreAttribute, true);
+            Jre jre = new Jre(name, configuration, project.getObjects());
+            configuration.defaultDependencies(dependencies -> {
+                jre.finalizeValues();
+                setupRepository(project, jre);
+                dependencies.add(project.getDependencies().create(dependencyNotation(jre)));
+            });
+            return jre;
+        });
+        project.getExtensions().add(EXTENSION_NAME, jresContainer);
+    }
+
+    private void setupRepository(Project project, Jre jre) {
+        RepositoryHandler repositories = project.getRepositories();
+
+        /*
+         * Define the appropriate repository for the given JRE vendor and version
+         *
+         * For Oracle/OpenJDK/AdoptOpenJDK we define a repository per-version.
+         */
+        String repoName = REPO_NAME_PREFIX + jre.getVendor() + "_" + jre.getVersion();
+        String repoUrl;
+        String artifactPattern;
+
+        if (jre.getVendor().equals(VENDOR_ADOPTIUM)) {
+            repoUrl = "https://github.com/adoptium/temurin" + jre.getMajor() + "-binaries/releases/download/";
+
+            if (jre.getMajor().equals("8")) {
+                // JDK-8 updates are always suffixed with 'U' (fe OpenJDK8U).
+                artifactPattern = "jdk"
+                    + jre.getBaseVersion()
+                    + "-"
+                    + jre.getBuild()
+                    + "/OpenJDK"
+                    + jre.getMajor()
+                    + "U"
+                    + "-jre_[classifier]_[module]_hotspot_"
+                    + jre.getBaseVersion()
+                    + jre.getBuild()
+                    + ".[ext]";
+            } else {
+                // JDK updates are suffixed with 'U' (fe OpenJDK17U), whereas GA releases are not (fe OpenJDK17).
+                // To distinguish between those, the GA releases have only major version component (fe 17+32),
+                // the updates always have minor/patch components (fe 17.0.1+12), checking for the presence of
+                // version separator '.' should be enough.
+                artifactPattern = "jdk-" + jre.getBaseVersion() + "+" + jre.getBuild() + "/OpenJDK" + jre.getMajor()
+                // JDK-20 does use 'U' suffix all the time, no matter it is update or GA release
+                    + (jre.getBaseVersion().contains(".") || jre.getBaseVersion().matches("^2\\d+$") ? "U" : "")
+                    + "-jre_[classifier]_[module]_hotspot_"
+                    + jre.getBaseVersion()
+                    + "_"
+                    + jre.getBuild()
+                    + ".[ext]";
+            }
+        } else {
+            throw new GradleException("Unknown JDK vendor [" + jre.getVendor() + "]");
+        }
+
+        // Define the repository if we haven't already
+        if (repositories.findByName(repoName) == null) {
+            repositories.ivy(repo -> {
+                repo.setName(repoName);
+                repo.setUrl(repoUrl);
+                repo.metadataSources(IvyArtifactRepository.MetadataSources::artifact);
+                repo.patternLayout(layout -> layout.artifact(artifactPattern));
+                repo.content(repositoryContentDescriptor -> repositoryContentDescriptor.includeGroup(groupName(jre)));
+            });
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public static NamedDomainObjectContainer<Jre> getContainer(Project project) {
+        return (NamedDomainObjectContainer<Jre>) project.getExtensions().getByName(EXTENSION_NAME);
+    }
+
+    private static String dependencyNotation(Jre jre) {
+        String platformDep = jre.getPlatform().equals("darwin") || jre.getPlatform().equals("mac") ? "mac" : jre.getPlatform();
+        String extension = jre.getPlatform().equals("windows") ? "zip" : "tar.gz";
+
+        return groupName(jre) + ":" + platformDep + ":" + jre.getBaseVersion() + ":" + jre.getArchitecture() + "@" + extension;
+    }
+
+    private static String groupName(Jre jre) {
+        return jre.getVendor() + "_" + jre.getMajor() + "_jre";
+    }
+
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/LoggedExec.java b/buildSrc/src/main/java/org/opensearch/gradle/LoggedExec.java
index 0512ed72f5e47..1a78a7dbb2d10 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/LoggedExec.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/LoggedExec.java
@@ -47,6 +47,7 @@
 import org.gradle.process.JavaExecSpec;
 
 import javax.inject.Inject;
+
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchDistribution.java b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchDistribution.java
index 968bd13bd4011..0575c23fee9f6 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchDistribution.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchDistribution.java
@@ -101,7 +101,7 @@ public boolean shouldExtract() {
     private final Property<String> version;
     private final Property<Type> type;
     private final Property<Platform> platform;
-    private final Property<Boolean> bundledJdk;
+    private final Property<JavaPackageType> bundledJdk;
     private final Property<Boolean> failIfUnavailable;
     private final Configuration extracted;
 
@@ -120,7 +120,7 @@ public boolean shouldExtract() {
         this.type = objectFactory.property(Type.class);
         this.type.convention(Type.ARCHIVE);
         this.platform = objectFactory.property(Platform.class);
-        this.bundledJdk = objectFactory.property(Boolean.class);
+        this.bundledJdk = objectFactory.property(JavaPackageType.class);
         this.failIfUnavailable = objectFactory.property(Boolean.class).convention(true);
         this.extracted = extractedConfiguration;
     }
@@ -154,8 +154,8 @@ public void setType(Type type) {
         this.type.set(type);
     }
 
-    public boolean getBundledJdk() {
-        return bundledJdk.getOrElse(true);
+    public JavaPackageType getBundledJdk() {
+        return bundledJdk.getOrElse(JavaPackageType.JDK);
     }
 
     public boolean isDocker() {
@@ -163,7 +163,7 @@ public boolean isDocker() {
         return type == Type.DOCKER;
     }
 
-    public void setBundledJdk(Boolean bundledJdk) {
+    public void setBundledJdk(JavaPackageType bundledJdk) {
         this.bundledJdk.set(bundledJdk);
     }
 
@@ -266,7 +266,7 @@ void finalizeValues() {
         }
 
         if (bundledJdk.isPresent() == false) {
-            bundledJdk.set(true);
+            bundledJdk.set(JavaPackageType.JDK);
         }
 
         version.finalizeValue();
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchJavaPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchJavaPlugin.java
index c701c47f9e68c..018781c7b30c4 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchJavaPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchJavaPlugin.java
@@ -34,6 +34,7 @@
 
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar;
 import nebula.plugin.info.InfoBrokerPlugin;
+
 import org.opensearch.gradle.info.BuildParams;
 import org.opensearch.gradle.info.GlobalBuildInfoPlugin;
 import org.opensearch.gradle.precommit.PrecommitTaskPlugin;
@@ -256,10 +257,10 @@ private static void configureJarManifest(Project project) {
             );
         });
 
-        project.getPluginManager().apply("nebula.info-broker");
-        project.getPluginManager().apply("nebula.info-basic");
-        project.getPluginManager().apply("nebula.info-java");
-        project.getPluginManager().apply("nebula.info-jar");
+        project.getPluginManager().apply("com.netflix.nebula.info-broker");
+        project.getPluginManager().apply("com.netflix.nebula.info-basic");
+        project.getPluginManager().apply("com.netflix.nebula.info-java");
+        project.getPluginManager().apply("com.netflix.nebula.info-jar");
     }
 
     private static void configureJavadoc(Project project) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchTestBasePlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchTestBasePlugin.java
index 9d6e78014916d..549e7f5c6d4df 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchTestBasePlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/OpenSearchTestBasePlugin.java
@@ -33,8 +33,10 @@
 package org.opensearch.gradle;
 
 import com.github.jengelman.gradle.plugins.shadow.ShadowBasePlugin;
+
 import org.opensearch.gradle.info.BuildParams;
 import org.opensearch.gradle.info.GlobalBuildInfoPlugin;
+import org.opensearch.gradle.jvm.JvmTestSuiteHelper;
 import org.opensearch.gradle.test.ErrorReportingTestListener;
 import org.opensearch.gradle.util.Util;
 import org.gradle.api.Action;
@@ -218,7 +220,15 @@ public void execute(Task t) {
                 // Add the shadow JAR artifact itself
                 FileCollection shadowJar = project.files(project.getTasks().named("shadowJar"));
 
-                test.setClasspath(test.getClasspath().minus(mainRuntime).plus(shadowConfig).plus(shadowJar));
+                // See please https://docs.gradle.org/8.1/userguide/upgrading_version_8.html#test_task_default_classpath
+                test.setClasspath(
+                    JvmTestSuiteHelper.getDefaultTestSuite(project)
+                        .map(suite -> suite.getSources().getRuntimeClasspath())
+                        .orElseGet(() -> test.getClasspath())
+                        .minus(mainRuntime)
+                        .plus(shadowConfig)
+                        .plus(shadowJar)
+                );
             });
         });
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/PublishPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/PublishPlugin.java
index d164b54c7506c..97e923c366598 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/PublishPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/PublishPlugin.java
@@ -36,6 +36,7 @@
 import com.github.jengelman.gradle.plugins.shadow.ShadowExtension;
 import groovy.util.Node;
 import groovy.util.NodeList;
+
 import org.opensearch.gradle.info.BuildParams;
 import org.opensearch.gradle.precommit.PomValidationPrecommitPlugin;
 import org.opensearch.gradle.util.Util;
@@ -45,7 +46,7 @@
 import org.gradle.api.XmlProvider;
 import org.gradle.api.artifacts.ProjectDependency;
 import org.gradle.api.plugins.BasePlugin;
-import org.gradle.api.plugins.BasePluginConvention;
+import org.gradle.api.plugins.BasePluginExtension;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.publish.PublishingExtension;
 import org.gradle.api.publish.maven.MavenPublication;
@@ -55,6 +56,9 @@
 import org.gradle.api.tasks.bundling.Jar;
 import org.gradle.language.base.plugins.LifecycleBasePlugin;
 
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
 import java.util.concurrent.Callable;
 
 import static org.opensearch.gradle.util.GradleUtils.maybeConfigure;
@@ -63,7 +67,8 @@ public class PublishPlugin implements Plugin<Project> {
 
     @Override
     public void apply(Project project) {
-        project.getPluginManager().apply("nebula.maven-base-publish");
+        project.getPluginManager().apply("com.netflix.nebula.maven-base-publish");
+        project.getPluginManager().apply("com.netflix.nebula.maven-nebula-publish");
         project.getPluginManager().apply(PomValidationPrecommitPlugin.class);
 
         configureJavadocJar(project);
@@ -72,7 +77,7 @@ public void apply(Project project) {
     }
 
     private static String getArchivesBaseName(Project project) {
-        return project.getConvention().getPlugin(BasePluginConvention.class).getArchivesBaseName();
+        return project.getExtensions().getByType(BasePluginExtension.class).getArchivesBaseName();
     }
 
     /**Configuration generation of maven poms. */
@@ -88,7 +93,7 @@ public String call() throws Exception {
                 return String.format(
                     "%s/distributions/%s-%s.pom",
                     project.getBuildDir(),
-                    getArchivesBaseName(project),
+                    pomTask.getName().toLowerCase().contains("zip") ? project.getName() : getArchivesBaseName(project),
                     project.getVersion()
                 );
             }
@@ -104,8 +109,12 @@ public String call() throws Exception {
             // Here we manually add any project dependencies in the "shadow" configuration to our generated POM
             publication.getPom().withXml(xml -> {
                 Node root = xml.asNode();
-                root.appendNode("name", project.getName());
-                root.appendNode("description", project.getDescription());
+                if (((NodeList) root.get("name")).isEmpty()) {
+                    root.appendNode("name", project.getName());
+                }
+                if (((NodeList) root.get("description")).isEmpty()) {
+                    root.appendNode("description", project.getDescription());
+                }
                 Node dependenciesNode = (Node) ((NodeList) root.get("dependencies")).get(0);
                 project.getConfigurations().getByName(ShadowBasePlugin.CONFIGURATION_NAME).getAllDependencies().all(dependency -> {
                     if (dependency instanceof ProjectDependency) {
@@ -125,13 +134,17 @@ public String call() throws Exception {
             // Add git origin info to generated POM files
             publication.getPom().withXml(PublishPlugin::addScmInfo);
 
-            // have to defer this until archivesBaseName is set
-            project.afterEvaluate(p -> publication.setArtifactId(getArchivesBaseName(project)));
-
-            // publish sources and javadoc for Java projects.
-            if (project.getPluginManager().hasPlugin("opensearch.java")) {
-                publication.artifact(project.getTasks().getByName("sourcesJar"));
-                publication.artifact(project.getTasks().getByName("javadocJar"));
+            if (!publication.getName().toLowerCase().contains("zip")) {
+                // have to defer this until archivesBaseName is set
+                project.afterEvaluate(p -> publication.setArtifactId(getArchivesBaseName(project)));
+
+                // publish sources and javadoc for Java projects.
+                if (project.getPluginManager().hasPlugin("opensearch.java")) {
+                    publication.artifact(project.getTasks().getByName("sourcesJar"));
+                    publication.artifact(project.getTasks().getByName("javadocJar"));
+                }
+            } else {
+                project.afterEvaluate(p -> publication.setArtifactId(project.getName()));
             }
 
             generatePomTask.configure(
@@ -143,9 +156,49 @@ public String call() throws Exception {
 
     private static void addScmInfo(XmlProvider xml) {
         Node root = xml.asNode();
-        root.appendNode("url", Util.urlFromOrigin(BuildParams.getGitOrigin()));
-        Node scmNode = root.appendNode("scm");
-        scmNode.appendNode("url", BuildParams.getGitOrigin());
+        Node url = null, scm = null;
+
+        for (final Object child : root.children()) {
+            if (child instanceof Node) {
+                final Node node = (Node) child;
+                final Object name = node.name();
+
+                try {
+                    // For Gradle 6.8 and below, the class is groovy.xml.QName
+                    // For Gradle 7.4 and above, the class is groovy.namespace.QName
+                    if (name != null && name.getClass().getSimpleName().equals("QName")) {
+                        final MethodHandle handle = MethodHandles.publicLookup()
+                            .findVirtual(name.getClass(), "matches", MethodType.methodType(boolean.class, Object.class))
+                            .bindTo(name);
+
+                        if ((boolean) handle.invoke("url")) {
+                            url = node;
+                        } else if ((boolean) handle.invoke("scm")) {
+                            scm = node;
+                        }
+                    }
+                } catch (final Throwable ex) {
+                    // Not a suitable QName type we could use ...
+                }
+
+                if ("url".equals(name)) {
+                    url = node;
+                } else if ("scm".equals(name)) {
+                    scm = node;
+                }
+            }
+        }
+
+        // Only include URL section if it is not provided in the POM already
+        if (url == null) {
+            root.appendNode("url", Util.urlFromOrigin(BuildParams.getGitOrigin()));
+        }
+
+        // Only include SCM section if it is not provided in the POM already
+        if (scm == null) {
+            Node scmNode = root.appendNode("scm");
+            scmNode.appendNode("url", BuildParams.getGitOrigin());
+        }
     }
 
     /** Adds a javadocJar task to generate a jar containing javadocs. */
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/RepositoriesSetupPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/RepositoriesSetupPlugin.java
index 30847f0648c5c..63b88f671c84c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/RepositoriesSetupPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/RepositoriesSetupPlugin.java
@@ -92,10 +92,9 @@ public static void configureRepositories(Project project) {
                 throw new GradleException("Malformed lucene snapshot version: " + luceneVersion);
             }
             String revision = matcher.group(1);
-            // TODO(cleanup) - Setup own lucene snapshot repo
             MavenArtifactRepository luceneRepo = repos.maven(repo -> {
                 repo.setName("lucene-snapshots");
-                repo.setUrl("https://artifacts.opensearch.org/snapshots/lucene/");
+                repo.setUrl("https://d1nvenhzbhpy0q.cloudfront.net/snapshots/lucene/");
             });
             repos.exclusiveContent(exclusiveRepo -> {
                 exclusiveRepo.filter(
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/VersionProperties.java b/buildSrc/src/main/java/org/opensearch/gradle/VersionProperties.java
index 2b50e59de04d3..4d8b62d95dff1 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/VersionProperties.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/VersionProperties.java
@@ -31,6 +31,8 @@
 
 package org.opensearch.gradle;
 
+import org.apache.commons.lang3.StringUtils;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.HashMap;
@@ -54,7 +56,7 @@ public static String getLucene() {
         return lucene;
     }
 
-    public static String getBundledJdk(final String platform) {
+    public static String getBundledJdk(final String platform, final String arch) {
         switch (platform) {
             case "darwin": // fall trough
             case "mac":
@@ -62,7 +64,7 @@ public static String getBundledJdk(final String platform) {
             case "freebsd":
                 return bundledJdkFreeBSD;
             case "linux":
-                return bundledJdkLinux;
+                return getBundledJdkLinux(arch);
             case "windows":
                 return bundledJdkWindows;
             default:
@@ -70,6 +72,14 @@ public static String getBundledJdk(final String platform) {
         }
     }
 
+    public static String getBundledJdk(final String platform) {
+        return getBundledJdk(platform, null);
+    }
+
+    public static String getBundledJre(final String platform, final String arch) {
+        return getBundledJdk(platform, arch);
+    }
+
     public static String getBundledJdkVendor() {
         return bundledJdkVendor;
     }
@@ -84,6 +94,10 @@ public static Map<String, String> getVersions() {
     private static final String bundledJdkFreeBSD;
     private static final String bundledJdkLinux;
     private static final String bundledJdkWindows;
+    private static final String bundledJdkLinux_arm64;
+    private static final String bundledJdkLinux_x64;
+    private static final String bundledJdkLinux_s390x;
+    private static final String bundledJdkLinux_ppc64le;
     private static final String bundledJdkVendor;
     private static final Map<String, String> versions = new HashMap<String, String>();
 
@@ -98,6 +112,12 @@ public static Map<String, String> getVersions() {
         bundledJdkLinux = props.getProperty("bundled_jdk_linux", bundledJdk);
         bundledJdkWindows = props.getProperty("bundled_jdk_windows", bundledJdk);
 
+        // Bundled JDKs per architecture (linux platform)
+        bundledJdkLinux_arm64 = props.getProperty("bundled_jdk_linux_arm64", bundledJdkLinux);
+        bundledJdkLinux_x64 = props.getProperty("bundled_jdk_linux_x64", bundledJdkLinux);
+        bundledJdkLinux_s390x = props.getProperty("bundled_jdk_linux_s390x", bundledJdkLinux);
+        bundledJdkLinux_ppc64le = props.getProperty("bundled_jdk_linux_ppc64le", bundledJdkLinux);
+
         for (String property : props.stringPropertyNames()) {
             versions.put(property, props.getProperty(property));
         }
@@ -119,4 +139,24 @@ private static Properties getVersionProperties() {
     public static boolean isOpenSearchSnapshot() {
         return opensearch.endsWith("-SNAPSHOT");
     }
+
+    private static String getBundledJdkLinux(String arch) {
+        if (StringUtils.isBlank(arch)) {
+            return bundledJdkLinux;
+        }
+
+        switch (arch) {
+            case "aarch64":
+            case "arm64":
+                return bundledJdkLinux_arm64;
+            case "x64":
+                return bundledJdkLinux_x64;
+            case "s390x":
+                return bundledJdkLinux_s390x;
+            case "ppc64le":
+                return bundledJdkLinux_ppc64le;
+            default:
+                throw new IllegalArgumentException("unknown platform [" + arch + "] for 'linux' platform");
+        }
+    }
 }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerBuildTask.java b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerBuildTask.java
index bb2a6d37362e1..08f0e7488a43c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerBuildTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerBuildTask.java
@@ -52,6 +52,7 @@
 import org.gradle.workers.WorkerExecutor;
 
 import javax.inject.Inject;
+
 import java.io.IOException;
 import java.util.Arrays;
 
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportPlugin.java
index 92777638982d2..5455875a96611 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportPlugin.java
@@ -56,13 +56,9 @@ public void apply(Project project) {
 
         Provider<DockerSupportService> dockerSupportServiceProvider = project.getGradle()
             .getSharedServices()
-            .registerIfAbsent(
-                DOCKER_SUPPORT_SERVICE_NAME,
-                DockerSupportService.class,
-                spec -> spec.parameters(
-                    params -> { params.setExclusionsFile(new File(project.getRootDir(), DOCKER_ON_LINUX_EXCLUSIONS_FILE)); }
-                )
-            );
+            .registerIfAbsent(DOCKER_SUPPORT_SERVICE_NAME, DockerSupportService.class, spec -> spec.parameters(params -> {
+                params.setExclusionsFile(new File(project.getRootDir(), DOCKER_ON_LINUX_EXCLUSIONS_FILE));
+            }));
 
         // Ensure that if we are trying to run any DockerBuildTask tasks, we assert an available Docker installation exists
         project.getGradle().getTaskGraph().whenReady(graph -> {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportService.java b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportService.java
index 2eb2852e3e55e..fc78792bb3551 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportService.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/docker/DockerSupportService.java
@@ -31,6 +31,7 @@
 
 package org.opensearch.gradle.docker;
 
+import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.Version;
 import org.opensearch.gradle.info.BuildParams;
 import org.gradle.api.GradleException;
@@ -40,9 +41,9 @@
 import org.gradle.api.services.BuildServiceParameters;
 import org.gradle.process.ExecOperations;
 import org.gradle.process.ExecResult;
-import org.apache.tools.ant.taskdefs.condition.Os;
 
 import javax.inject.Inject;
+
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
@@ -68,7 +69,9 @@ public abstract class DockerSupportService implements BuildService<DockerSupport
     // Defines the possible locations of the Docker CLI. These will be searched in order.
     private static String[] DOCKER_BINARIES_UNIX = { "/usr/bin/docker", "/usr/local/bin/docker" };
 
-    private static String[] DOCKER_BINARIES_WINDOWS = { System.getenv("PROGRAMFILES") + "\\Docker\\Docker\\resources\\bin\\docker.exe" };
+    private static String[] DOCKER_BINARIES_WINDOWS = {
+        System.getenv("PROGRAMFILES") + "\\Docker\\Docker\\resources\\bin\\docker.exe",
+        System.getenv("SystemRoot") + "\\System32\\docker.exe" /* Github Actions */ };
 
     private static String[] DOCKER_BINARIES = Os.isFamily(Os.FAMILY_WINDOWS) ? DOCKER_BINARIES_WINDOWS : DOCKER_BINARIES_UNIX;
 
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/http/WaitForHttpResource.java b/buildSrc/src/main/java/org/opensearch/gradle/http/WaitForHttpResource.java
index 41f4054910d97..54c544a299b84 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/http/WaitForHttpResource.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/http/WaitForHttpResource.java
@@ -39,6 +39,7 @@
 import javax.net.ssl.KeyManager;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.TrustManagerFactory;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -82,6 +83,24 @@ public WaitForHttpResource(String protocol, String host, int numberOfNodes) thro
         this(new URL(protocol + "://" + host + "/_cluster/health?wait_for_nodes=>=" + numberOfNodes + "&wait_for_status=yellow"));
     }
 
+    public WaitForHttpResource(String protocol, String host, String username, String password, int numberOfNodes)
+        throws MalformedURLException {
+        this(
+            new URL(
+                protocol
+                    + "://"
+                    + username
+                    + ":"
+                    + password
+                    + "@"
+                    + host
+                    + "/_cluster/health?wait_for_nodes=>="
+                    + numberOfNodes
+                    + "&wait_for_status=yellow"
+            )
+        );
+    }
+
     public WaitForHttpResource(URL url) {
         this.url = url;
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/info/BuildParams.java b/buildSrc/src/main/java/org/opensearch/gradle/info/BuildParams.java
index 331794c9c2dd7..a9ccb75569002 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/info/BuildParams.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/info/BuildParams.java
@@ -192,8 +192,8 @@ public void setRuntimeJavaHome(File runtimeJavaHome) {
             BuildParams.runtimeJavaHome = requireNonNull(runtimeJavaHome);
         }
 
-        public void setIsRutimeJavaHomeSet(boolean isRutimeJavaHomeSet) {
-            BuildParams.isRuntimeJavaHomeSet = isRutimeJavaHomeSet;
+        public void setIsRuntimeJavaHomeSet(boolean isRuntimeJavaHomeSet) {
+            BuildParams.isRuntimeJavaHomeSet = isRuntimeJavaHomeSet;
         }
 
         public void setJavaVersions(List<JavaHome> javaVersions) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/info/GlobalBuildInfoPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/info/GlobalBuildInfoPlugin.java
index ccd82372bb11b..448ba8a96ef02 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/info/GlobalBuildInfoPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/info/GlobalBuildInfoPlugin.java
@@ -45,13 +45,16 @@
 import org.gradle.internal.jvm.Jvm;
 import org.gradle.internal.jvm.inspection.JvmInstallationMetadata;
 import org.gradle.internal.jvm.inspection.JvmMetadataDetector;
+import org.gradle.jvm.toolchain.internal.InstallationLocation;
 import org.gradle.util.GradleVersion;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.io.UncheckedIOException;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -72,8 +75,8 @@
 
 public class GlobalBuildInfoPlugin implements Plugin<Project> {
     private static final Logger LOGGER = Logging.getLogger(GlobalBuildInfoPlugin.class);
-    private static final String DEFAULT_LEGACY_VERSION_JAVA_FILE_PATH = "server/src/main/java/org/opensearch/LegacyESVersion.java";
-    private static final String DEFAULT_VERSION_JAVA_FILE_PATH = "server/src/main/java/org/opensearch/Version.java";
+    private static final String DEFAULT_LEGACY_VERSION_JAVA_FILE_PATH = "libs/core/src/main/java/org/opensearch/LegacyESVersion.java";
+    private static final String DEFAULT_VERSION_JAVA_FILE_PATH = "libs/core/src/main/java/org/opensearch/Version.java";
     private static Integer _defaultParallel = null;
 
     private final JvmMetadataDetector jvmMetadataDetector;
@@ -113,7 +116,7 @@ public void apply(Project project) {
             params.reset();
             params.setRuntimeJavaHome(runtimeJavaHome);
             params.setRuntimeJavaVersion(determineJavaVersion("runtime java.home", runtimeJavaHome, minimumRuntimeVersion));
-            params.setIsRutimeJavaHomeSet(runtimeJavaHomeOpt.isPresent());
+            params.setIsRuntimeJavaHomeSet(runtimeJavaHomeOpt.isPresent());
             params.setRuntimeJavaDetails(getJavaInstallation(runtimeJavaHome).getDisplayName());
             params.setJavaVersions(getAvailableJavaVersions(minimumCompilerVersion));
             params.setMinimumCompilerVersion(minimumCompilerVersion);
@@ -150,7 +153,7 @@ private static BwcVersions resolveBwcVersions(File root) {
             versionLines.addAll(IOUtils.readLines(fis2, "UTF-8"));
             return new BwcVersions(versionLines);
         } catch (IOException e) {
-            throw new IllegalStateException("Unable to resolve to resolve bwc versions from versionsFile.", e);
+            throw new IllegalStateException("Unable to resolve bwc versions from versionsFile.", e);
         }
     }
 
@@ -196,7 +199,29 @@ private JavaVersion determineJavaVersion(String description, File javaHome, Java
     }
 
     private JvmInstallationMetadata getJavaInstallation(File javaHome) {
-        return jvmMetadataDetector.getMetadata(javaHome);
+        final InstallationLocation location = new InstallationLocation(javaHome, "Java home");
+
+        try {
+            try {
+                // The getMetadata(File) is used by Gradle pre-7.6
+                return (JvmInstallationMetadata) MethodHandles.publicLookup()
+                    .findVirtual(JvmMetadataDetector.class, "getMetadata", MethodType.methodType(JvmInstallationMetadata.class, File.class))
+                    .bindTo(jvmMetadataDetector)
+                    .invokeExact(location.getLocation());
+            } catch (NoSuchMethodException | IllegalAccessException ex) {
+                // The getMetadata(InstallationLocation) is used by Gradle post-7.6
+                return (JvmInstallationMetadata) MethodHandles.publicLookup()
+                    .findVirtual(
+                        JvmMetadataDetector.class,
+                        "getMetadata",
+                        MethodType.methodType(JvmInstallationMetadata.class, InstallationLocation.class)
+                    )
+                    .bindTo(jvmMetadataDetector)
+                    .invokeExact(location);
+            }
+        } catch (Throwable ex) {
+            throw new IllegalStateException("Unable to find suitable JvmMetadataDetector::getMetadata", ex);
+        }
     }
 
     private List<JavaHome> getAvailableJavaVersions(JavaVersion minimumCompilerVersion) {
@@ -206,7 +231,7 @@ private List<JavaHome> getAvailableJavaVersions(JavaVersion minimumCompilerVersi
             String javaHomeEnvVarName = getJavaHomeEnvVarName(Integer.toString(version));
             if (System.getenv(javaHomeEnvVarName) != null) {
                 File javaHomeDirectory = new File(findJavaHome(Integer.toString(version)));
-                JvmInstallationMetadata javaInstallation = jvmMetadataDetector.getMetadata(javaHomeDirectory);
+                JvmInstallationMetadata javaInstallation = getJavaInstallation(javaHomeDirectory);
                 JavaHome javaHome = JavaHome.of(version, providers.provider(() -> {
                     int actualVersion = Integer.parseInt(javaInstallation.getLanguageVersion().getMajorVersion());
                     if (actualVersion != version) {
@@ -220,14 +245,6 @@ private List<JavaHome> getAvailableJavaVersions(JavaVersion minimumCompilerVersi
         return javaVersions;
     }
 
-    private static boolean isCurrentJavaHome(File javaHome) {
-        try {
-            return Files.isSameFile(javaHome.toPath(), Jvm.current().getJavaHome().toPath());
-        } catch (IOException e) {
-            throw new UncheckedIOException(e);
-        }
-    }
-
     private static String getTestSeed() {
         String testSeedProperty = System.getProperty("tests.seed");
         final String testSeed;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalBwcGitPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalBwcGitPlugin.java
index 11270e5c9a51d..159270d28e3d6 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalBwcGitPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalBwcGitPlugin.java
@@ -50,10 +50,12 @@
 import org.gradle.process.ExecSpec;
 
 import javax.inject.Inject;
+
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
+
 import static java.util.Arrays.asList;
 
 public class InternalBwcGitPlugin implements Plugin<Project> {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveCheckPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveCheckPlugin.java
index 2a162e5f12d7b..4949476038bdb 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveCheckPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveCheckPlugin.java
@@ -44,6 +44,7 @@
 import org.gradle.api.tasks.TaskProvider;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -73,12 +74,14 @@ public void apply(Project project) {
             .create("distributionArchiveCheck", DistributionArchiveCheckExtension.class);
 
         File archiveExtractionDir = calculateArchiveExtractionDir(project);
-
         // sanity checks if archives can be extracted
         TaskProvider<Copy> checkExtraction = registerCheckExtractionTask(project, buildDistTask, archiveExtractionDir);
+        checkExtraction.configure(InternalDistributionArchiveSetupPlugin.configure(buildTaskName));
         TaskProvider<Task> checkLicense = registerCheckLicenseTask(project, checkExtraction);
+        checkLicense.configure(InternalDistributionArchiveSetupPlugin.configure(buildTaskName));
 
         TaskProvider<Task> checkNotice = registerCheckNoticeTask(project, checkExtraction);
+        checkNotice.configure(InternalDistributionArchiveSetupPlugin.configure(buildTaskName));
         TaskProvider<Task> checkTask = project.getTasks().named("check");
         checkTask.configure(task -> {
             task.dependsOn(checkExtraction);
@@ -118,7 +121,7 @@ public void execute(Task task) {
     }
 
     private TaskProvider<Task> registerCheckLicenseTask(Project project, TaskProvider<Copy> checkExtraction) {
-        TaskProvider<Task> checkLicense = project.getTasks().register("checkLicense", task -> {
+        return project.getTasks().register("checkLicense", task -> {
             task.dependsOn(checkExtraction);
             task.doLast(new Action<Task>() {
                 @Override
@@ -138,7 +141,6 @@ public void execute(Task task) {
                 }
             });
         });
-        return checkLicense;
     }
 
     private TaskProvider<Copy> registerCheckExtractionTask(Project project, TaskProvider<Task> buildDistTask, File archiveExtractionDir) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveSetupPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveSetupPlugin.java
index 8adfbff424278..7ab91448252f2 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveSetupPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionArchiveSetupPlugin.java
@@ -41,9 +41,9 @@
 import org.gradle.api.Task;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.type.ArtifactTypeDefinition;
-import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.logging.Logger;
 import org.gradle.api.logging.Logging;
+import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.tasks.AbstractCopyTask;
 import org.gradle.api.tasks.Sync;
 import org.gradle.api.tasks.TaskContainer;
@@ -52,6 +52,7 @@
 import org.gradle.api.tasks.bundling.Compression;
 import org.gradle.api.tasks.bundling.Zip;
 import org.gradle.internal.os.OperatingSystem;
+
 import java.io.File;
 
 import static org.opensearch.gradle.util.Util.capitalize;
@@ -87,7 +88,7 @@ public void apply(Project project) {
         configureTarDefaults(project);
     }
 
-    private Action<Task> configure(String name) {
+    static Action<Task> configure(String name) {
         return (Task task) -> task.onlyIf(s -> {
             if (OperatingSystem.current().isWindows()) {
                 // On Windows, include only Windows distributions and integTestZip
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionBwcSetupPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionBwcSetupPlugin.java
index dd2393702fe2b..6892af1b17f97 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionBwcSetupPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionBwcSetupPlugin.java
@@ -48,6 +48,7 @@
 import org.gradle.language.base.plugins.LifecycleBasePlugin;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
@@ -76,12 +77,9 @@ public InternalDistributionBwcSetupPlugin(ProviderFactory providerFactory) {
     @Override
     public void apply(Project project) {
         project.getRootProject().getPluginManager().apply(GlobalBuildInfoPlugin.class);
-        BuildParams.getBwcVersions()
-            .forPreviousUnreleased(
-                (BwcVersions.UnreleasedVersionInfo unreleasedVersion) -> {
-                    configureBwcProject(project.project(unreleasedVersion.gradleProjectPath), unreleasedVersion);
-                }
-            );
+        BuildParams.getBwcVersions().forPreviousUnreleased((BwcVersions.UnreleasedVersionInfo unreleasedVersion) -> {
+            configureBwcProject(project.project(unreleasedVersion.gradleProjectPath), unreleasedVersion);
+        });
     }
 
     private void configureBwcProject(Project project, BwcVersions.UnreleasedVersionInfo versionInfo) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionDownloadPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionDownloadPlugin.java
index f4368b1cecc59..6a54612320c6c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionDownloadPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/internal/InternalDistributionDownloadPlugin.java
@@ -37,6 +37,7 @@
 import org.opensearch.gradle.DistributionDependency;
 import org.opensearch.gradle.DistributionDownloadPlugin;
 import org.opensearch.gradle.DistributionResolution;
+import org.opensearch.gradle.JavaPackageType;
 import org.opensearch.gradle.OpenSearchDistribution;
 import org.opensearch.gradle.Version;
 import org.opensearch.gradle.VersionProperties;
@@ -99,7 +100,7 @@ private void registerInternalDistributionResolutions(NamedDomainObjectContainer<
         resolutions.register("bwc", distributionResolution -> distributionResolution.setResolver((project, distribution) -> {
             BwcVersions.UnreleasedVersionInfo unreleasedInfo = bwcVersions.unreleasedInfo(Version.fromString(distribution.getVersion()));
             if (unreleasedInfo != null) {
-                if (!distribution.getBundledJdk()) {
+                if (distribution.getBundledJdk() == JavaPackageType.NONE) {
                     throw new GradleException(
                         "Configuring a snapshot bwc distribution ('"
                             + distribution.getName()
@@ -167,8 +168,10 @@ private static String distributionProjectName(OpenSearchDistribution distributio
             ? ""
             : "-" + architecture.toString().toLowerCase();
 
-        if (distribution.getBundledJdk() == false) {
+        if (distribution.getBundledJdk() == JavaPackageType.NONE) {
             projectName += "no-jdk-";
+        } else if (distribution.getBundledJdk() == JavaPackageType.JRE) {
+            projectName += "jre-";
         }
         switch (distribution.getType()) {
             case ARCHIVE:
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/jvm/JvmTestSuiteHelper.java b/buildSrc/src/main/java/org/opensearch/gradle/jvm/JvmTestSuiteHelper.java
new file mode 100644
index 0000000000000..3b8e88c9f1a8f
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/jvm/JvmTestSuiteHelper.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.jvm;
+
+import org.gradle.api.Project;
+import org.gradle.api.plugins.JvmTestSuitePlugin;
+import org.gradle.api.plugins.jvm.JvmTestSuite;
+import org.gradle.testing.base.TestSuite;
+import org.gradle.testing.base.TestingExtension;
+
+import java.util.Optional;
+
+public final class JvmTestSuiteHelper {
+    private JvmTestSuiteHelper() {}
+
+    /**
+     * Gets the default test suite. This method assumes the Java plugin is applied,
+     * adapted from {@link org.gradle.api.plugins.internal.JavaPluginHelper} since it is not
+     * available in Gradle releases predated 8.1.
+     */
+    public static Optional<JvmTestSuite> getDefaultTestSuite(Project project) {
+        TestingExtension testing = project.getExtensions().findByType(TestingExtension.class);
+        if (testing == null) {
+            return Optional.empty();
+        }
+
+        TestSuite defaultTestSuite = testing.getSuites().findByName(JvmTestSuitePlugin.DEFAULT_TEST_SUITE_NAME);
+        if (!(defaultTestSuite instanceof JvmTestSuite)) {
+            return Optional.empty();
+        }
+
+        return Optional.of((JvmTestSuite) defaultTestSuite);
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/pluginzip/Publish.java b/buildSrc/src/main/java/org/opensearch/gradle/pluginzip/Publish.java
new file mode 100644
index 0000000000000..a80471f6e6271
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/pluginzip/Publish.java
@@ -0,0 +1,113 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.gradle.pluginzip;
+
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.Task;
+import org.gradle.api.publish.PublishingExtension;
+import org.gradle.api.publish.maven.MavenPublication;
+import org.gradle.api.publish.maven.plugins.MavenPublishPlugin;
+
+import java.nio.file.Path;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class Publish implements Plugin<Project> {
+    private final static String DEFAULT_GROUP_ID = "org.opensearch.plugin";
+
+    public final static String PUBLICATION_NAME = "pluginZip";
+    public final static String STAGING_REPO = "zipStaging";
+    public final static String LOCAL_STAGING_REPO_PATH = "/build/local-staging-repo";
+    // TODO: Does the path ^^ need to use platform dependant file separators ?
+
+    /**
+     * This method returns a "default" groupId value ("{@link #DEFAULT_GROUP_ID}").
+     * It is possible to have the `group` property unspecified in which case the default value is used instead.
+     * See <a href="https://github.com/opensearch-project/OpenSearch/pull/4156#issuecomment-1230397082">GitHub discussion</a>
+     * for details.
+     *
+     * @deprecated This method will be removed in OpenSearch 3.x and `group` property will be required
+     * @return The default groupId value
+     */
+    @Deprecated
+    public static String getDefaultGroupId(Project project) {
+        project.getLogger()
+            .warn(
+                String.format(
+                    "The 'project.group' property is empty, a default value '%s' will be used instead. "
+                        + "Please notice that in OpenSearch 3.x the 'project.group' property will be required.",
+                    DEFAULT_GROUP_ID
+                )
+            );
+        return DEFAULT_GROUP_ID;
+    }
+
+    private boolean isZipPublicationPresent(Project project) {
+        PublishingExtension pe = project.getExtensions().findByType(PublishingExtension.class);
+        if (pe == null) {
+            return false;
+        }
+        return pe.getPublications().findByName(PUBLICATION_NAME) != null;
+    }
+
+    private void addLocalMavenRepo(Project project) {
+        final Path buildDirectory = project.getRootDir().toPath();
+        project.getExtensions().configure(PublishingExtension.class, publishing -> {
+            publishing.repositories(repositories -> {
+                repositories.maven(maven -> {
+                    maven.setName(STAGING_REPO);
+                    maven.setUrl(buildDirectory.toString() + LOCAL_STAGING_REPO_PATH);
+                });
+            });
+        });
+    }
+
+    private void addZipArtifact(Project project) {
+        project.getExtensions().configure(PublishingExtension.class, publishing -> {
+            publishing.publications(publications -> {
+                MavenPublication mavenZip = (MavenPublication) publications.findByName(PUBLICATION_NAME);
+                if (mavenZip != null) {
+                    mavenZip.artifact(project.getTasks().named("bundlePlugin"));
+                    if (mavenZip.getGroupId().isEmpty()) {
+                        mavenZip.setGroupId(getDefaultGroupId(project));
+                    }
+                }
+            });
+        });
+    }
+
+    @Override
+    public void apply(Project project) {
+        project.getPluginManager().apply("com.netflix.nebula.maven-nebula-publish");
+        project.getPluginManager().apply(MavenPublishPlugin.class);
+        project.afterEvaluate(evaluatedProject -> {
+            if (isZipPublicationPresent(project)) {
+                addLocalMavenRepo(project);
+                addZipArtifact(project);
+                Task validatePluginZipPom = project.getTasks().findByName("validatePluginZipPom");
+                if (validatePluginZipPom != null) {
+                    validatePluginZipPom.dependsOn("generatePomFileForNebulaPublication");
+                }
+
+                // There are number of tasks prefixed by 'publishPluginZipPublication', f.e.:
+                // publishPluginZipPublicationToZipStagingRepository, publishPluginZipPublicationToMavenLocal
+                final Set<Task> publishPluginZipPublicationToTasks = project.getTasks()
+                    .stream()
+                    .filter(t -> t.getName().startsWith("publishPluginZipPublicationTo"))
+                    .collect(Collectors.toSet());
+                if (!publishPluginZipPublicationToTasks.isEmpty()) {
+                    publishPluginZipPublicationToTasks.forEach(t -> t.dependsOn("generatePomFileForNebulaPublication"));
+                }
+            } else {
+                project.getLogger()
+                    .warn(String.format("Plugin 'opensearch.pluginzip' is applied but no '%s' publication is defined.", PUBLICATION_NAME));
+            }
+        });
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/FilePermissionsTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/FilePermissionsTask.java
index 9ffd472151b4b..2c17666d8ee0c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/FilePermissionsTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/FilePermissionsTask.java
@@ -31,29 +31,32 @@
 
 package org.opensearch.gradle.precommit;
 
-import java.io.File;
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.attribute.PosixFileAttributeView;
-import java.nio.file.attribute.PosixFilePermission;
-import java.util.List;
-import java.util.Set;
-import java.util.stream.Collectors;
-
 import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.util.GradleUtils;
 import org.gradle.api.DefaultTask;
 import org.gradle.api.GradleException;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.FileTree;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SkipWhenEmpty;
 import org.gradle.api.tasks.StopExecutionException;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.util.PatternFilterable;
 import org.gradle.api.tasks.util.PatternSet;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.attribute.PosixFileAttributeView;
+import java.nio.file.attribute.PosixFilePermission;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
 /**
  * Checks source files for correct file permissions.
  */
@@ -92,6 +95,8 @@ private static boolean isExecutableFile(File file) {
      */
     @InputFiles
     @SkipWhenEmpty
+    @IgnoreEmptyDirectories
+    @PathSensitive(PathSensitivity.RELATIVE)
     public FileCollection getFiles() {
         return GradleUtils.getJavaSourceSets(getProject())
             .stream()
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenApisPrecommitPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenApisPrecommitPlugin.java
index 328edda8b1787..6b89aa8b60197 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenApisPrecommitPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenApisPrecommitPlugin.java
@@ -34,7 +34,9 @@
 
 import de.thetaphi.forbiddenapis.gradle.CheckForbiddenApis;
 import de.thetaphi.forbiddenapis.gradle.ForbiddenApisPlugin;
+
 import groovy.lang.Closure;
+
 import org.opensearch.gradle.ExportOpenSearchBuildResourcesTask;
 import org.opensearch.gradle.info.BuildParams;
 import org.opensearch.gradle.util.GradleUtils;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenPatternsTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenPatternsTask.java
index f57c190496452..6ef1e77f5138f 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenPatternsTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ForbiddenPatternsTask.java
@@ -36,10 +36,13 @@
 import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.FileTree;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SkipWhenEmpty;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.util.PatternFilterable;
@@ -100,9 +103,11 @@ public ForbiddenPatternsTask() {
 
     @InputFiles
     @SkipWhenEmpty
+    @IgnoreEmptyDirectories
+    @PathSensitive(PathSensitivity.RELATIVE)
     public FileCollection getFiles() {
-        return getProject().getConvention()
-            .getPlugin(JavaPluginConvention.class)
+        return getProject().getExtensions()
+            .getByType(JavaPluginExtension.class)
             .getSourceSets()
             .stream()
             .map(sourceSet -> sourceSet.getAllSource().matching(filesFilter))
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellPrecommitPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellPrecommitPlugin.java
index 87bf03cec3587..429028c9bf841 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellPrecommitPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellPrecommitPlugin.java
@@ -44,11 +44,11 @@ public class JarHellPrecommitPlugin extends PrecommitPlugin {
     @Override
     public TaskProvider<? extends Task> createTask(Project project) {
         Configuration jarHellConfig = project.getConfigurations().create("jarHell");
-        if (BuildParams.isInternal() && project.getPath().equals(":libs:opensearch-core") == false) {
+        if (BuildParams.isInternal() && project.getPath().equals(":libs:opensearch-common") == false) {
             // External plugins will depend on this already via transitive dependencies.
             // Internal projects are not all plugins, so make sure the check is available
             // we are not doing this for this project itself to avoid jar hell with itself
-            project.getDependencies().add("jarHell", project.project(":libs:opensearch-core"));
+            project.getDependencies().add("jarHell", project.project(":libs:opensearch-common"));
         }
 
         TaskProvider<JarHellTask> jarHell = project.getTasks().register("jarHell", JarHellTask.class);
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellTask.java
index c6a0d7abf7da1..7726133562e9f 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/JarHellTask.java
@@ -33,7 +33,6 @@
 package org.opensearch.gradle.precommit;
 
 import org.opensearch.gradle.LoggedExec;
-
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.CompileClasspath;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/LoggerUsageTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/LoggerUsageTask.java
index 1fd092b7f268f..db215fb65ef95 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/LoggerUsageTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/LoggerUsageTask.java
@@ -34,9 +34,10 @@
 
 import org.opensearch.gradle.LoggedExec;
 import org.gradle.api.file.FileCollection;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Classpath;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.PathSensitive;
 import org.gradle.api.tasks.PathSensitivity;
@@ -79,9 +80,10 @@ public void setClasspath(FileCollection classpath) {
     @InputFiles
     @PathSensitive(PathSensitivity.RELATIVE)
     @SkipWhenEmpty
+    @IgnoreEmptyDirectories
     public FileCollection getClassDirectories() {
-        return getProject().getConvention()
-            .getPlugin(JavaPluginConvention.class)
+        return getProject().getExtensions()
+            .getByType(JavaPluginExtension.class)
             .getSourceSets()
             .stream()
             // Don't pick up all source sets like the java9 ones as logger-check doesn't support the class format
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/TestingConventionsTasks.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/TestingConventionsTasks.java
index 5e42cc99dd79e..d66b1f9d25cdd 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/TestingConventionsTasks.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/TestingConventionsTasks.java
@@ -32,6 +32,8 @@
 package org.opensearch.gradle.precommit;
 
 import groovy.lang.Closure;
+
+import org.opensearch.gradle.jvm.JvmTestSuiteHelper;
 import org.opensearch.gradle.util.GradleUtils;
 import org.opensearch.gradle.util.Util;
 import org.gradle.api.DefaultTask;
@@ -39,6 +41,7 @@
 import org.gradle.api.Task;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.FileTree;
+import org.gradle.api.plugins.jvm.JvmTestSuite;
 import org.gradle.api.tasks.Classpath;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.OutputFile;
@@ -46,6 +49,11 @@
 import org.gradle.api.tasks.SourceSetContainer;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.testing.Test;
+import org.gradle.api.tasks.util.PatternFilterable;
+import org.gradle.api.tasks.util.PatternSet;
+import org.gradle.internal.Factory;
+
+import javax.inject.Inject;
 
 import java.io.File;
 import java.io.IOException;
@@ -85,13 +93,39 @@ public TestingConventionsTasks() {
         naming = getProject().container(TestingConventionRule.class);
     }
 
+    @Inject
+    protected Factory<PatternSet> getPatternSetFactory() {
+        throw new UnsupportedOperationException();
+    }
+
     @Input
     public Map<String, Set<File>> getClassFilesPerEnabledTask() {
         return getProject().getTasks()
             .withType(Test.class)
             .stream()
             .filter(Task::getEnabled)
-            .collect(Collectors.toMap(Task::getPath, task -> task.getCandidateClassFiles().getFiles()));
+            .collect(Collectors.toMap(Task::getPath, task -> {
+                // See please https://docs.gradle.org/8.1/userguide/upgrading_version_8.html#test_task_default_classpath
+                final JvmTestSuite jvmTestSuite = JvmTestSuiteHelper.getDefaultTestSuite(getProject()).orElse(null);
+                if (jvmTestSuite != null) {
+                    final PatternFilterable patternSet = getPatternSetFactory().create()
+                        .include(task.getIncludes())
+                        .exclude(task.getExcludes());
+
+                    final Set<File> files = jvmTestSuite.getSources()
+                        .getOutput()
+                        .getClassesDirs()
+                        .getAsFileTree()
+                        .matching(patternSet)
+                        .getFiles();
+
+                    if (!files.isEmpty()) {
+                        return files;
+                    }
+                }
+
+                return task.getCandidateClassFiles().getFiles();
+            }));
     }
 
     @Input
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditPrecommitPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditPrecommitPlugin.java
index 5d707ce2b9f28..d83f1b01ee043 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditPrecommitPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditPrecommitPlugin.java
@@ -51,7 +51,7 @@ public class ThirdPartyAuditPrecommitPlugin extends PrecommitPlugin {
     public TaskProvider<? extends Task> createTask(Project project) {
         project.getPlugins().apply(CompileOnlyResolvePlugin.class);
         project.getConfigurations().create("forbiddenApisCliJar");
-        project.getDependencies().add("forbiddenApisCliJar", "de.thetaphi:forbiddenapis:3.2");
+        project.getDependencies().add("forbiddenApisCliJar", "de.thetaphi:forbiddenapis:3.5.1");
 
         Configuration jdkJarHellConfig = project.getConfigurations().create(JDK_JAR_HELL_CONFIG_NAME);
         if (BuildParams.isInternal() && project.getPath().equals(":libs:opensearch-core") == false) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditTask.java
index ee68d2740e279..9e740b4e061cf 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ThirdPartyAuditTask.java
@@ -32,6 +32,7 @@
 package org.opensearch.gradle.precommit;
 
 import de.thetaphi.forbiddenapis.cli.CliMain;
+
 import org.apache.commons.io.output.NullOutputStream;
 import org.opensearch.gradle.LoggedExec;
 import org.opensearch.gradle.OS;
@@ -47,6 +48,7 @@
 import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Classpath;
 import org.gradle.api.tasks.CompileClasspath;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFile;
 import org.gradle.api.tasks.InputFiles;
@@ -78,9 +80,7 @@
 @CacheableTask
 public class ThirdPartyAuditTask extends DefaultTask {
 
-    private static final Pattern MISSING_CLASS_PATTERN = Pattern.compile(
-        "WARNING: Class '(.*)' cannot be loaded \\(.*\\)\\. Please fix the classpath!"
-    );
+    private static final Pattern MISSING_CLASS_PATTERN = Pattern.compile("DEBUG: Class '(.*)' cannot be loaded \\(.*\\)\\.");
 
     private static final Pattern VIOLATION_PATTERN = Pattern.compile("\\s\\sin ([a-zA-Z0-9$.]+) \\(.*\\)");
     private static final int SIG_KILL_EXIT_VALUE = 137;
@@ -105,6 +105,8 @@ public class ThirdPartyAuditTask extends DefaultTask {
 
     private final Property<JavaVersion> targetCompatibility = getProject().getObjects().property(JavaVersion.class);
 
+    public boolean jarHellEnabled = true;
+
     @Input
     public Property<JavaVersion> getTargetCompatibility() {
         return targetCompatibility;
@@ -195,6 +197,7 @@ public Set<String> getMissingClassExcludes() {
 
     @Classpath
     @SkipWhenEmpty
+    @IgnoreEmptyDirectories
     public Set<File> getJarsToScan() {
         // These are SelfResolvingDependency, and some of them backed by file collections, like the Gradle API files,
         // or dependencies added as `files(...)`, we can't be sure if those are third party or not.
@@ -232,9 +235,13 @@ public void runThirdPartyAudit() throws IOException {
             violationsClasses.add(violationMatcher.group(1));
         }
 
-        Set<String> jdkJarHellClasses = runJdkJarHellCheck();
+        Set<String> jdkJarHellClasses = null;
+        if (this.jarHellEnabled) {
+            jdkJarHellClasses = runJdkJarHellCheck();
+        }
 
         if (missingClassExcludes != null) {
+            assertNoPointlessExclusions("are not missing", missingClassExcludes, missingClasses);
             long bogousExcludesCount = Stream.concat(missingClassExcludes.stream(), violationsExcludes.stream())
                 .filter(each -> missingClasses.contains(each) == false)
                 .filter(each -> violationsClasses.contains(each) == false)
@@ -245,11 +252,12 @@ public void runThirdPartyAudit() throws IOException {
                     "All excluded classes seem to have no issues. " + "This is sometimes an indication that the check silently failed"
                 );
             }
-            assertNoPointlessExclusions("are not missing", missingClassExcludes, missingClasses);
             missingClasses.removeAll(missingClassExcludes);
         }
         assertNoPointlessExclusions("have no violations", violationsExcludes, violationsClasses);
-        assertNoPointlessExclusions("do not generate jar hell with the JDK", jdkJarHellExcludes, jdkJarHellClasses);
+        if (this.jarHellEnabled) {
+            assertNoPointlessExclusions("do not generate jar hell with the JDK", jdkJarHellExcludes, jdkJarHellClasses);
+        }
 
         if (missingClassExcludes == null && (missingClasses.isEmpty() == false)) {
             getLogger().info("Found missing classes, but task is configured to ignore all of them:\n {}", formatClassList(missingClasses));
@@ -270,7 +278,9 @@ public void runThirdPartyAudit() throws IOException {
             throw new IllegalStateException("Audit of third party dependencies failed");
         }
 
-        assertNoJarHell(jdkJarHellClasses);
+        if (this.jarHellEnabled) {
+            assertNoJarHell(jdkJarHellClasses);
+        }
 
         // Mark successful third party audit check
         getSuccessMarker().getParentFile().mkdirs();
@@ -357,7 +367,7 @@ private String runForbiddenAPIsCli() throws IOException {
             spec.jvmArgs("-Xmx1g");
             spec.jvmArgs(LoggedExec.shortLivedArgs());
             spec.getMainClass().set("de.thetaphi.forbiddenapis.cli.CliMain");
-            spec.args("-f", getSignatureFile().getAbsolutePath(), "-d", getJarExpandDir(), "--allowmissingclasses");
+            spec.args("-f", getSignatureFile().getAbsolutePath(), "-d", getJarExpandDir(), "--debug", "--allowmissingclasses");
             spec.setErrorOutput(errorOut);
             if (getLogger().isInfoEnabled() == false) {
                 spec.setStandardOutput(new NullOutputStream());
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonAgainstSchemaTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonAgainstSchemaTask.java
index ff28197feb02b..d829071c07e3c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonAgainstSchemaTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonAgainstSchemaTask.java
@@ -33,12 +33,14 @@
 package org.opensearch.gradle.precommit;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import com.networknt.schema.JsonSchema;
 import com.networknt.schema.JsonSchemaException;
 import com.networknt.schema.JsonSchemaFactory;
 import com.networknt.schema.SchemaValidatorsConfig;
 import com.networknt.schema.SpecVersion;
 import com.networknt.schema.ValidationMessage;
+
 import org.gradle.api.DefaultTask;
 import org.gradle.api.UncheckedIOException;
 import org.gradle.api.file.FileCollection;
@@ -103,6 +105,7 @@ public void validate(InputChanges inputChanges) throws IOException {
         File jsonSchemaOnDisk = getJsonSchema();
         getLogger().debug("JSON schema : [{}]", jsonSchemaOnDisk.getAbsolutePath());
         SchemaValidatorsConfig config = new SchemaValidatorsConfig();
+        config.setEcma262Validator(true);
         JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V7);
         JsonSchema jsonSchema = factory.getSchema(mapper.readTree(jsonSchemaOnDisk), config);
         Map<File, Set<String>> errors = new LinkedHashMap<>();
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonNoKeywordsTask.java b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonNoKeywordsTask.java
index b3ac804566e29..c69420f2216b2 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonNoKeywordsTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/precommit/ValidateJsonNoKeywordsTask.java
@@ -36,6 +36,7 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+
 import org.gradle.api.DefaultTask;
 import org.gradle.api.GradleException;
 import org.gradle.api.file.FileCollection;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTar.java b/buildSrc/src/main/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTar.java
index 7b8e9c9c925ba..1423b52c443d9 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTar.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/tar/SymbolicLinkPreservingTar.java
@@ -65,6 +65,11 @@
  * This task is necessary because the built-in task {@link org.gradle.api.tasks.bundling.Tar} does not preserve symbolic links.
  */
 public class SymbolicLinkPreservingTar extends Tar {
+    private long lastModifiedTimestamp = 0;
+
+    public void setLastModifiedTimestamp(long lastModifiedTimestamp) {
+        this.lastModifiedTimestamp = lastModifiedTimestamp;
+    }
 
     @Override
     protected CopyAction createCopyAction() {
@@ -80,7 +85,7 @@ protected CopyAction createCopyAction() {
                 compressor = new SimpleCompressor();
                 break;
         }
-        return new SymbolicLinkPreservingTarCopyAction(getArchiveFile(), compressor, isPreserveFileTimestamps());
+        return new SymbolicLinkPreservingTarCopyAction(getArchiveFile(), compressor, isPreserveFileTimestamps(), lastModifiedTimestamp);
     }
 
     private static class SymbolicLinkPreservingTarCopyAction implements CopyAction {
@@ -88,15 +93,18 @@ private static class SymbolicLinkPreservingTarCopyAction implements CopyAction {
         private final Provider<RegularFile> tarFile;
         private final ArchiveOutputStreamFactory compressor;
         private final boolean isPreserveFileTimestamps;
+        private final long lastModifiedTimestamp;
 
         SymbolicLinkPreservingTarCopyAction(
             final Provider<RegularFile> tarFile,
             final ArchiveOutputStreamFactory compressor,
-            final boolean isPreserveFileTimestamps
+            final boolean isPreserveFileTimestamps,
+            final long lastModifiedTimestamp
         ) {
             this.tarFile = tarFile;
             this.compressor = compressor;
             this.isPreserveFileTimestamps = isPreserveFileTimestamps;
+            this.lastModifiedTimestamp = lastModifiedTimestamp;
         }
 
         @Override
@@ -219,7 +227,7 @@ private void handleProcessingException(final FileCopyDetailsInternal details, fi
         }
 
         private long getModTime(final FileCopyDetails details) {
-            return isPreserveFileTimestamps ? details.getLastModified() : 0;
+            return isPreserveFileTimestamps ? details.getLastModified() : lastModifiedTimestamp;
         }
 
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/DistroTestPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/test/DistroTestPlugin.java
index a77155aacf723..a420c8b63b02c 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/DistroTestPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/DistroTestPlugin.java
@@ -34,9 +34,10 @@
 
 import org.opensearch.gradle.Architecture;
 import org.opensearch.gradle.DistributionDownloadPlugin;
-import org.opensearch.gradle.OpenSearchDistribution;
+import org.opensearch.gradle.JavaPackageType;
 import org.opensearch.gradle.Jdk;
 import org.opensearch.gradle.JdkDownloadPlugin;
+import org.opensearch.gradle.OpenSearchDistribution;
 import org.opensearch.gradle.SystemPropertyCommandLineArgumentProvider;
 import org.opensearch.gradle.Version;
 import org.opensearch.gradle.VersionProperties;
@@ -48,6 +49,7 @@
 import org.opensearch.gradle.util.Util;
 import org.opensearch.gradle.vagrant.VagrantBasePlugin;
 import org.opensearch.gradle.vagrant.VagrantExtension;
+import org.opensearch.gradle.vagrant.VagrantMachine;
 import org.gradle.api.Action;
 import org.gradle.api.NamedDomainObjectContainer;
 import org.gradle.api.Plugin;
@@ -61,7 +63,6 @@
 import org.gradle.api.tasks.Copy;
 import org.gradle.api.tasks.TaskProvider;
 import org.gradle.api.tasks.testing.Test;
-import org.opensearch.gradle.vagrant.VagrantMachine;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -71,13 +72,14 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
 public class DistroTestPlugin implements Plugin<Project> {
-    private static final String SYSTEM_JDK_VERSION = "8u242+b08";
-    private static final String SYSTEM_JDK_VENDOR = "adoptopenjdk";
-    private static final String GRADLE_JDK_VERSION = "17.0.2+8";
+    private static final String SYSTEM_JDK_VERSION = "11.0.20+8";
+    private static final String SYSTEM_JDK_VENDOR = "adoptium";
+    private static final String GRADLE_JDK_VERSION = "17.0.8+7";
     private static final String GRADLE_JDK_VENDOR = "adoptium";
 
     // all distributions used by distro tests. this is temporary until tests are per distribution
@@ -119,8 +121,8 @@ public void apply(Project project) {
             TaskProvider<?> depsTask = project.getTasks().register(taskname + "#deps");
             depsTask.configure(t -> t.dependsOn(distribution, examplePlugin));
             depsTasks.put(taskname, depsTask);
-            // TODO - suppressing failure temporarily where duplicate tasks are created for docker.
-            try {
+            // Avoid duplicate tasks such as docker registered in lifecycleTasks
+            if (project.getTasksByName(taskname, false).isEmpty()) {
                 TaskProvider<Test> destructiveTask = configureTestTask(project, taskname, distribution, t -> {
                     t.onlyIf(t2 -> distribution.isDocker() == false || dockerSupport.get().getDockerAvailability().isAvailable);
                     addSysprop(t, DISTRIBUTION_SYSPROP, distribution::getFilepath);
@@ -134,12 +136,10 @@ public void apply(Project project) {
                 }
                 destructiveDistroTest.configure(t -> t.dependsOn(destructiveTask));
                 lifecycleTasks.get(distribution.getType()).configure(t -> t.dependsOn(destructiveTask));
-            } catch (Exception ex) {
-                System.out.println(ex.getMessage());
             }
 
             if ((distribution.getType() == OpenSearchDistribution.Type.DEB || distribution.getType() == OpenSearchDistribution.Type.RPM)
-                && distribution.getBundledJdk()) {
+                && distribution.getBundledJdk() != JavaPackageType.NONE) {
                 for (Version version : BuildParams.getBwcVersions().getIndexCompatible()) {
                     if (version.before("6.3.0")) {
                         continue; // before opening xpack
@@ -197,13 +197,9 @@ public void apply(Project project) {
 
             // windows boxes get windows distributions, and linux boxes get linux distributions
             if (isWindows(vmProject)) {
-                configureVMWrapperTasks(
-                    vmProject,
-                    windowsTestTasks,
-                    depsTasks,
-                    wrapperTask -> { vmLifecyleTasks.get(OpenSearchDistribution.Type.ARCHIVE).configure(t -> t.dependsOn(wrapperTask)); },
-                    vmDependencies
-                );
+                configureVMWrapperTasks(vmProject, windowsTestTasks, depsTasks, wrapperTask -> {
+                    vmLifecyleTasks.get(OpenSearchDistribution.Type.ARCHIVE).configure(t -> t.dependsOn(wrapperTask));
+                }, vmDependencies);
             } else {
                 for (Entry<OpenSearchDistribution.Type, List<TaskProvider<Test>>> entry : linuxTestTasks.entrySet()) {
                     OpenSearchDistribution.Type type = entry.getKey();
@@ -385,8 +381,8 @@ private List<OpenSearchDistribution> configureDistributions(Project project) {
                 OpenSearchDistribution.Type.RPM,
                 OpenSearchDistribution.Type.DOCKER
             )) {
-                for (boolean bundledJdk : Arrays.asList(true, false)) {
-                    if (bundledJdk == false) {
+                for (JavaPackageType bundledJdk : Set.of(JavaPackageType.NONE, JavaPackageType.JDK)) {
+                    if (bundledJdk == JavaPackageType.NONE) {
                         // We'll never publish an ARM (arm64) build without a bundled JDK.
                         if (architecture == Architecture.ARM64) {
                             continue;
@@ -409,8 +405,8 @@ private List<OpenSearchDistribution> configureDistributions(Project project) {
                 OpenSearchDistribution.Platform.LINUX,
                 OpenSearchDistribution.Platform.WINDOWS
             )) {
-                for (boolean bundledJdk : Arrays.asList(true, false)) {
-                    if (bundledJdk == false && architecture != Architecture.X64) {
+                for (JavaPackageType bundledJdk : Set.of(JavaPackageType.NONE, JavaPackageType.JDK)) {
+                    if (bundledJdk == JavaPackageType.NONE && architecture != Architecture.X64) {
                         // We will never publish distributions for non-x86 (amd64) platforms
                         // without a bundled JDK
                         continue;
@@ -438,7 +434,7 @@ private static OpenSearchDistribution createDistro(
         Architecture architecture,
         OpenSearchDistribution.Type type,
         OpenSearchDistribution.Platform platform,
-        boolean bundledJdk,
+        JavaPackageType bundledJdk,
         String version
     ) {
         String name = distroId(type, platform, bundledJdk, architecture) + "-" + version;
@@ -472,11 +468,12 @@ private static boolean isWindows(Project project) {
     private static String distroId(
         OpenSearchDistribution.Type type,
         OpenSearchDistribution.Platform platform,
-        boolean bundledJdk,
+        JavaPackageType bundledJdk,
         Architecture architecture
     ) {
-        return (type == OpenSearchDistribution.Type.ARCHIVE ? platform + "-" : "") + type + (bundledJdk ? "" : "-no-jdk")
-            + (architecture == Architecture.X64 ? "" : "-" + architecture.toString().toLowerCase());
+        return (type == OpenSearchDistribution.Type.ARCHIVE ? platform + "-" : "") + type + (bundledJdk != JavaPackageType.NONE
+            ? (bundledJdk == JavaPackageType.JDK ? "" : "-jre")
+            : "-no-jdk") + (architecture == Architecture.X64 ? "" : "-" + architecture.toString().toLowerCase());
     }
 
     private static String destructiveDistroTestTaskName(OpenSearchDistribution distro) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/GradleDistroTestTask.java b/buildSrc/src/main/java/org/opensearch/gradle/test/GradleDistroTestTask.java
index 2443a30fc05fb..fa417da1a1007 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/GradleDistroTestTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/GradleDistroTestTask.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.gradle.test;
 
+import org.opensearch.gradle.vagrant.VagrantMachine;
 import org.opensearch.gradle.vagrant.VagrantShellTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.options.Option;
-import org.opensearch.gradle.vagrant.VagrantMachine;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/JNAKernel32Library.java b/buildSrc/src/main/java/org/opensearch/gradle/test/JNAKernel32Library.java
index 9d575364f5546..1484dcba1e290 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/JNAKernel32Library.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/JNAKernel32Library.java
@@ -34,6 +34,7 @@
 
 import com.sun.jna.Native;
 import com.sun.jna.WString;
+
 import org.apache.tools.ant.taskdefs.condition.Os;
 
 public class JNAKernel32Library {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/RestIntegTestTask.java b/buildSrc/src/main/java/org/opensearch/gradle/test/RestIntegTestTask.java
index d1671146d0b77..aec31d02b9bee 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/RestIntegTestTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/RestIntegTestTask.java
@@ -32,7 +32,10 @@
 
 package org.opensearch.gradle.test;
 
+import groovy.lang.Closure;
+
 import org.opensearch.gradle.testclusters.StandaloneRestIntegTestTask;
+import org.gradle.api.Task;
 import org.gradle.api.tasks.CacheableTask;
 
 /**
@@ -41,4 +44,12 @@
  * conventional configured tasks of {@link RestIntegTestTask}
  */
 @CacheableTask
-public class RestIntegTestTask extends StandaloneRestIntegTestTask {}
+public abstract class RestIntegTestTask extends StandaloneRestIntegTestTask implements TestSuiteConventionMappings {
+    @SuppressWarnings("rawtypes")
+    @Override
+    public Task configure(Closure closure) {
+        final Task t = super.configure(closure);
+        applyConventionMapping(getProject(), getConventionMapping());
+        return t;
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/TestSuiteConventionMappings.java b/buildSrc/src/main/java/org/opensearch/gradle/test/TestSuiteConventionMappings.java
new file mode 100644
index 0000000000000..f03b59509a2f9
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/TestSuiteConventionMappings.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.test;
+
+import org.opensearch.gradle.jvm.JvmTestSuiteHelper;
+import org.gradle.api.Project;
+import org.gradle.api.internal.ConventionMapping;
+
+// Temporary workaround for https://docs.gradle.org/8.1/userguide/upgrading_version_8.html#test_task_default_classpath
+interface TestSuiteConventionMappings {
+    default void applyConventionMapping(Project project, ConventionMapping conventionMapping) {
+        JvmTestSuiteHelper.getDefaultTestSuite(project).ifPresent(defaultTestSuite -> {
+            conventionMapping.map("testClassesDirs", () -> { return defaultTestSuite.getSources().getOutput().getClassesDirs(); });
+
+            conventionMapping.map("classpath", () -> { return defaultTestSuite.getSources().getRuntimeClasspath(); });
+        });
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/TestTask.java b/buildSrc/src/main/java/org/opensearch/gradle/test/TestTask.java
new file mode 100644
index 0000000000000..f7511a2ac7f1c
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/TestTask.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.test;
+
+import groovy.lang.Closure;
+
+import org.gradle.api.Task;
+import org.gradle.api.tasks.CacheableTask;
+import org.gradle.api.tasks.testing.Test;
+
+@CacheableTask
+public abstract class TestTask extends Test implements TestSuiteConventionMappings {
+    @SuppressWarnings("rawtypes")
+    @Override
+    public Task configure(Closure closure) {
+        final Task t = super.configure(closure);
+        applyConventionMapping(getProject(), getConventionMapping());
+        return t;
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestApiTask.java b/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestApiTask.java
index 399cd39d236d7..485561a305291 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestApiTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestApiTask.java
@@ -41,11 +41,14 @@
 import org.gradle.api.file.ConfigurableFileCollection;
 import org.gradle.api.file.FileSystemOperations;
 import org.gradle.api.file.FileTree;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.provider.ListProperty;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.OutputDirectory;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SkipWhenEmpty;
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.api.tasks.TaskAction;
@@ -54,6 +57,7 @@
 import org.gradle.internal.Factory;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -112,8 +116,10 @@ public boolean isSkipHasRestTestCheck() {
         return skipHasRestTestCheck;
     }
 
+    @IgnoreEmptyDirectories
     @SkipWhenEmpty
     @InputFiles
+    @PathSensitive(PathSensitivity.RELATIVE)
     public FileTree getInputDir() {
         FileTree coreFileTree = null;
         boolean projectHasYamlRestTests = skipHasRestTestCheck || projectHasYamlRestTests();
@@ -235,7 +241,7 @@ private File getTestOutputResourceDir() {
 
     private Optional<SourceSet> getSourceSet() {
         Project project = getProject();
-        return project.getConvention().findPlugin(JavaPluginConvention.class) == null
+        return project.getExtensions().findByType(JavaPluginExtension.class) == null
             ? Optional.empty()
             : Optional.ofNullable(GradleUtils.getJavaSourceSets(project).findByName(getSourceSetName()));
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestTestsTask.java b/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestTestsTask.java
index 56ce449f4cf6f..0d5af7ca06b50 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestTestsTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/test/rest/CopyRestTestsTask.java
@@ -41,11 +41,14 @@
 import org.gradle.api.file.ConfigurableFileCollection;
 import org.gradle.api.file.FileSystemOperations;
 import org.gradle.api.file.FileTree;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.provider.ListProperty;
+import org.gradle.api.tasks.IgnoreEmptyDirectories;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.OutputDirectory;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SkipWhenEmpty;
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.api.tasks.TaskAction;
@@ -54,6 +57,7 @@
 import org.gradle.internal.Factory;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.util.Objects;
 import java.util.Optional;
@@ -104,8 +108,10 @@ String getSourceSetName() {
         return sourceSetName;
     }
 
+    @IgnoreEmptyDirectories
     @SkipWhenEmpty
     @InputFiles
+    @PathSensitive(PathSensitivity.RELATIVE)
     public FileTree getInputDir() {
         FileTree coreFileTree = null;
         if (includeCore.get().isEmpty() == false) {
@@ -173,7 +179,7 @@ void copy() {
 
     private Optional<SourceSet> getSourceSet() {
         Project project = getProject();
-        return project.getConvention().findPlugin(JavaPluginConvention.class) == null
+        return project.getExtensions().findByType(JavaPluginExtension.class) == null
             ? Optional.empty()
             : Optional.ofNullable(GradleUtils.getJavaSourceSets(project).findByName(getSourceSetName()));
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/ExtensionsProperties.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/ExtensionsProperties.java
new file mode 100644
index 0000000000000..10a79e8325d0b
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/ExtensionsProperties.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.testclusters;
+
+public class ExtensionsProperties {
+    private String name;
+    private String uniqueId;
+    private String hostAddress;
+    private String port;
+    private String version;
+    private String opensearchVersion;
+    private String minimumCompatibleVersion;
+
+    public ExtensionsProperties(
+        String name,
+        String uniqueId,
+        String hostAddress,
+        String port,
+        String version,
+        String opensearchVersion,
+        String minimumCompatibleVersion
+    ) {
+        this.name = name;
+        this.uniqueId = uniqueId;
+        this.hostAddress = hostAddress;
+        this.port = port;
+        this.version = version;
+        this.opensearchVersion = opensearchVersion;
+        this.minimumCompatibleVersion = minimumCompatibleVersion;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getUniqueId() {
+        return uniqueId;
+    }
+
+    public void setUniqueId(String uniqueId) {
+        this.uniqueId = uniqueId;
+    }
+
+    public String getHostAddress() {
+        return hostAddress;
+    }
+
+    public void setHostAddress(String hostAddress) {
+        this.hostAddress = hostAddress;
+    }
+
+    public String getPort() {
+        return port;
+    }
+
+    public void setPort(String port) {
+        this.port = port;
+    }
+
+    public String getVersion() {
+        return version;
+    }
+
+    public void setVersion(String version) {
+        this.version = version;
+    }
+
+    public String getOpensearchVersion() {
+        return opensearchVersion;
+    }
+
+    public void setOpensearchVersion(String opensearchVersion) {
+        this.opensearchVersion = opensearchVersion;
+    }
+
+    public String getMinimumCompatibleVersion() {
+        return minimumCompatibleVersion;
+    }
+
+    public void setMinimumCompatibleVersion(String minimumCompatibleVersion) {
+        this.minimumCompatibleVersion = minimumCompatibleVersion;
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchCluster.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchCluster.java
index ef52adab6377a..287be63692ab2 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchCluster.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchCluster.java
@@ -180,6 +180,11 @@ public void setTestDistribution(TestDistribution distribution) {
         nodes.all(each -> each.setTestDistribution(distribution));
     }
 
+    @Override
+    public void extension(boolean extensionsEnabled) {
+        nodes.all(each -> each.extension(extensionsEnabled));
+    }
+
     @Override
     public void plugin(Provider<RegularFile> plugin) {
         nodes.all(each -> each.plugin(plugin));
@@ -235,6 +240,11 @@ public void keystorePassword(String password) {
         nodes.all(each -> each.keystorePassword(password));
     }
 
+    @Override
+    public void setSecure(boolean secure) {
+        nodes.all(each -> each.setSecure(secure));
+    }
+
     @Override
     public void cliSetup(String binTool, CharSequence... args) {
         nodes.all(each -> each.cliSetup(binTool, args));
@@ -524,12 +534,25 @@ public OpenSearchNode singleNode() {
     private void addWaitForClusterHealth() {
         waitConditions.put("cluster health yellow", (node) -> {
             try {
-                WaitForHttpResource wait = new WaitForHttpResource("http", getFirstNode().getHttpSocketURI(), nodes.size());
-
-                List<Map<String, String>> credentials = getFirstNode().getCredentials();
-                if (getFirstNode().getCredentials().isEmpty() == false) {
-                    wait.setUsername(credentials.get(0).get("useradd"));
-                    wait.setPassword(credentials.get(0).get("-p"));
+                WaitForHttpResource wait;
+                if (!getFirstNode().isSecure()) {
+                    wait = new WaitForHttpResource("http", getFirstNode().getHttpSocketURI(), nodes.size());
+                    List<Map<String, String>> credentials = getFirstNode().getCredentials();
+                    if (getFirstNode().getCredentials().isEmpty() == false) {
+                        wait.setUsername(credentials.get(0).get("useradd"));
+                        wait.setPassword(credentials.get(0).get("-p"));
+                    }
+                } else {
+                    wait = new WaitForHttpResource(
+                        "https",
+                        getFirstNode().getHttpSocketURI(),
+                        getFirstNode().getCredentials().get(0).get("username"),
+                        getFirstNode().getCredentials().get(0).get("password"),
+                        nodes.size()
+                    );
+                    wait.setUsername(getFirstNode().getCredentials().get(0).get("username"));
+                    wait.setPassword(getFirstNode().getCredentials().get(0).get("password"));
+                    wait.setCertificateAuthorities(getFirstNode().getExtraConfigFilesMap().get("root-ca.pem"));
                 }
                 return wait.wait(500);
             } catch (IOException e) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchNode.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchNode.java
index b051c15e81d6d..e5132c3afb518 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchNode.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/OpenSearchNode.java
@@ -34,13 +34,13 @@
 import org.apache.commons.io.FileUtils;
 import org.opensearch.gradle.Architecture;
 import org.opensearch.gradle.DistributionDownloadPlugin;
-import org.opensearch.gradle.OpenSearchDistribution;
 import org.opensearch.gradle.FileSupplier;
 import org.opensearch.gradle.Jdk;
 import org.opensearch.gradle.LazyPropertyList;
 import org.opensearch.gradle.LazyPropertyMap;
 import org.opensearch.gradle.LoggedExec;
 import org.opensearch.gradle.OS;
+import org.opensearch.gradle.OpenSearchDistribution;
 import org.opensearch.gradle.PropertyNormalization;
 import org.opensearch.gradle.ReaperService;
 import org.opensearch.gradle.Version;
@@ -142,6 +142,7 @@ public class OpenSearchNode implements TestClusterConfiguration {
     private final Map<String, Configuration> pluginAndModuleConfigurations = new HashMap<>();
     private final List<Provider<File>> plugins = new ArrayList<>();
     private final List<Provider<File>> modules = new ArrayList<>();
+    private boolean extensionsEnabled = false;
     final LazyPropertyMap<String, CharSequence> settings = new LazyPropertyMap<>("Settings", this);
     private final LazyPropertyMap<String, CharSequence> keystoreSettings = new LazyPropertyMap<>("Keystore", this);
     private final LazyPropertyMap<String, File> keystoreFiles = new LazyPropertyMap<>("Keystore files", this, FileEntry::new);
@@ -160,6 +161,7 @@ public class OpenSearchNode implements TestClusterConfiguration {
     private final Path httpPortsFile;
     private final Path tmpDir;
 
+    private boolean secure = false;
     private int currentDistro = 0;
     private TestDistribution testDistribution;
     private List<OpenSearchDistribution> distributions = new ArrayList<>();
@@ -205,6 +207,7 @@ public class OpenSearchNode implements TestClusterConfiguration {
         opensearchConfig = Config.getOpenSearchConfig(workingDir);
         legacyESConfig = Config.getLegacyESConfig(workingDir);
         currentConfig = opensearchConfig;
+        this.credentials.add(new HashMap<>());
     }
 
     /*
@@ -305,6 +308,11 @@ public String getName() {
         return nameCustomization.apply(name);
     }
 
+    @Internal
+    public boolean isSecure() {
+        return secure;
+    }
+
     @Internal
     public Version getVersion() {
         return Version.fromString(distributions.get(currentDistro).getVersion());
@@ -432,6 +440,11 @@ public void module(String moduleProjectPath) {
         module(maybeCreatePluginOrModuleDependency(moduleProjectPath));
     }
 
+    @Override
+    public void extension(boolean extensionsEnabled) {
+        this.extensionsEnabled = extensionsEnabled;
+    }
+
     @Override
     public void keystore(String key, String value) {
         keystoreSettings.put(key, value);
@@ -537,6 +550,11 @@ public void setPreserveDataDir(boolean preserveDataDir) {
         this.preserveDataDir = preserveDataDir;
     }
 
+    @Override
+    public void setSecure(boolean secure) {
+        this.secure = secure;
+    }
+
     @Override
     public void freeze() {
         requireNonNull(testDistribution, "null testDistribution passed when configuring test cluster `" + this + "`");
@@ -556,6 +574,18 @@ public Stream<String> logLines() throws IOException {
     @Override
     public synchronized void start() {
         LOGGER.info("Starting `{}`", this);
+        if (System.getProperty("tests.opensearch.secure") != null
+            && System.getProperty("tests.opensearch.secure").equalsIgnoreCase("true")) {
+            secure = true;
+        }
+        if (System.getProperty("tests.opensearch.username") != null) {
+            this.credentials.get(0).put("username", System.getProperty("tests.opensearch.username"));
+            LOGGER.info("Overwriting username to: " + this.getCredentials().get(0).get("username"));
+        }
+        if (System.getProperty("tests.opensearch.password") != null) {
+            this.credentials.get(0).put("password", System.getProperty("tests.opensearch.password"));
+            LOGGER.info("Overwriting password to: " + this.getCredentials().get(0).get("password"));
+        }
         if (Files.exists(getExtractedDistributionDir()) == false) {
             throw new TestClustersException("Can not start " + this + ", missing: " + getExtractedDistributionDir());
         }
@@ -609,6 +639,7 @@ public synchronized void start() {
         }
 
         logToProcessStdout("Creating " + currentConfig.command + " keystore with password set to [" + keystorePassword + "]");
+
         if (keystorePassword.length() > 0) {
             runOpenSearchBinScriptWithInput(keystorePassword + "\n" + keystorePassword, currentConfig.keystoreTool, "create", "-p");
         } else {
@@ -892,6 +923,10 @@ private void startOpenSearchProcess() {
         environment.clear();
         environment.putAll(getOpenSearchEnvironment());
 
+        if (extensionsEnabled) {
+            environment.put("OPENSEARCH_JAVA_OPTS", "-Dopensearch.experimental.feature.extensions.enabled=true");
+        }
+
         // don't buffer all in memory, make sure we don't block on the default pipes
         processBuilder.redirectError(ProcessBuilder.Redirect.appendTo(currentConfig.stderrFile.toFile()));
         processBuilder.redirectOutput(ProcessBuilder.Redirect.appendTo(currentConfig.stdoutFile.toFile()));
@@ -1467,6 +1502,11 @@ public List<?> getExtraConfigFiles() {
         return extraConfigFiles.getNormalizedCollection();
     }
 
+    @Internal
+    public Map<String, File> getExtraConfigFilesMap() {
+        return extraConfigFiles;
+    }
+
     @Override
     @Internal
     public boolean isProcessAlive() {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/RunTask.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/RunTask.java
index 01680050cf18f..c5035f3b082fe 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/RunTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/RunTask.java
@@ -66,22 +66,40 @@ public class RunTask extends DefaultTestClustersTask {
 
     private Boolean debug = false;
 
+    private Boolean debugServer = false;
+
     private Boolean preserveData = false;
 
     private Path dataDir = null;
 
     private String keystorePassword = "";
 
-    @Option(option = "debug-jvm", description = "Enable debugging configuration, to allow attaching a debugger to opensearch.")
+    @Option(option = "debug-jvm", description = "Run OpenSearch as a debug client, where it will try to connect to a debugging server at startup.")
     public void setDebug(boolean enabled) {
+        if (debugServer != null && debugServer == true) {
+            throw new IllegalStateException("Either --debug-jvm or --debug-server-jvm option should be specified (but not both)");
+        }
         this.debug = enabled;
     }
 
+    @Option(option = "debug-server-jvm", description = "Run OpenSearch as a debug server that will accept connections from a debugging client.")
+    public void setDebugServer(boolean enabled) {
+        if (debug != null && debug == true) {
+            throw new IllegalStateException("Either --debug-jvm or --debug-server-jvm option should be specified (but not both)");
+        }
+        this.debugServer = enabled;
+    }
+
     @Input
     public Boolean getDebug() {
         return debug;
     }
 
+    @Input
+    public Boolean getDebugServer() {
+        return debugServer;
+    }
+
     @Option(option = "data-dir", description = "Override the base data directory used by the testcluster")
     public void setDataDir(String dataDirStr) {
         dataDir = Paths.get(dataDirStr).toAbsolutePath();
@@ -162,9 +180,17 @@ public void beforeStart() {
                     node.setDataPath(getDataPath.apply(node));
                 }
                 if (debug) {
-                    logger.lifecycle("Running opensearch in debug mode, {} expecting running debug server on port {}", node, debugPort);
+                    logger.lifecycle(
+                        "Running opensearch in debug mode (client), {} expecting running debug server on port {}",
+                        node,
+                        debugPort
+                    );
                     node.jvmArgs("-agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=" + debugPort);
                     debugPort += 1;
+                } else if (debugServer) {
+                    logger.lifecycle("Running opensearch in debug mode (server), {} running server with debug port {}", node, debugPort);
+                    node.jvmArgs("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=" + debugPort);
+                    debugPort += 1;
                 }
                 if (keystorePassword.length() > 0) {
                     node.keystorePassword(keystorePassword);
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/StandaloneRestIntegTestTask.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/StandaloneRestIntegTestTask.java
index bf17daa6e2e6f..ddcbf77b0d5e6 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/StandaloneRestIntegTestTask.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/StandaloneRestIntegTestTask.java
@@ -32,11 +32,13 @@
 package org.opensearch.gradle.testclusters;
 
 import groovy.lang.Closure;
+
 import org.opensearch.gradle.FileSystemOperationsAware;
 import org.opensearch.gradle.test.Fixture;
 import org.opensearch.gradle.util.GradleUtils;
 import org.gradle.api.Task;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.services.internal.BuildServiceProvider;
 import org.gradle.api.services.internal.BuildServiceRegistryInternal;
 import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Internal;
@@ -46,6 +48,8 @@
 import org.gradle.internal.resources.ResourceLock;
 import org.gradle.internal.resources.SharedResource;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -58,7 +62,7 @@
  * {@link Nested} inputs.
  */
 @CacheableTask
-public class StandaloneRestIntegTestTask extends Test implements TestClustersAware, FileSystemOperationsAware {
+public abstract class StandaloneRestIntegTestTask extends Test implements TestClustersAware, FileSystemOperationsAware {
 
     private Collection<OpenSearchCluster> clusters = new HashSet<>();
     private Closure<Void> beforeStart;
@@ -120,16 +124,67 @@ public List<ResourceLock> getSharedResources() {
             serviceRegistry,
             TestClustersPlugin.THROTTLE_SERVICE_NAME
         );
-        SharedResource resource = serviceRegistry.forService(throttleProvider);
+        final SharedResource resource = getSharedResource(serviceRegistry, throttleProvider);
 
         int nodeCount = clusters.stream().mapToInt(cluster -> cluster.getNodes().size()).sum();
         if (nodeCount > 0) {
-            locks.add(resource.getResourceLock(Math.min(nodeCount, resource.getMaxUsages())));
+            locks.add(getResourceLock(resource, Math.min(nodeCount, resource.getMaxUsages())));
         }
 
         return Collections.unmodifiableList(locks);
     }
 
+    private SharedResource getSharedResource(
+        BuildServiceRegistryInternal serviceRegistry,
+        Provider<TestClustersThrottle> throttleProvider
+    ) {
+        try {
+            try {
+                // The forService(Provider) is used by Gradle pre-8.0
+                return (SharedResource) MethodHandles.publicLookup()
+                    .findVirtual(
+                        BuildServiceRegistryInternal.class,
+                        "forService",
+                        MethodType.methodType(SharedResource.class, Provider.class)
+                    )
+                    .bindTo(serviceRegistry)
+                    .invokeExact(throttleProvider);
+            } catch (NoSuchMethodException | IllegalAccessException ex) {
+                // The forService(BuildServiceProvider) is used by Gradle post-8.0
+                return (SharedResource) MethodHandles.publicLookup()
+                    .findVirtual(
+                        BuildServiceRegistryInternal.class,
+                        "forService",
+                        MethodType.methodType(SharedResource.class, BuildServiceProvider.class)
+                    )
+                    .bindTo(serviceRegistry)
+                    .invokeExact((BuildServiceProvider<TestClustersThrottle, ?>) throttleProvider);
+            }
+        } catch (Throwable ex) {
+            throw new IllegalStateException("Unable to find suitable BuildServiceRegistryInternal::forService", ex);
+        }
+    }
+
+    private ResourceLock getResourceLock(SharedResource resource, int nUsages) {
+        try {
+            try {
+                // The getResourceLock(int) is used by Gradle pre-7.5
+                return (ResourceLock) MethodHandles.publicLookup()
+                    .findVirtual(SharedResource.class, "getResourceLock", MethodType.methodType(ResourceLock.class, int.class))
+                    .bindTo(resource)
+                    .invokeExact(nUsages);
+            } catch (NoSuchMethodException | IllegalAccessException ex) {
+                // The getResourceLock() is used by Gradle post-7.4
+                return (ResourceLock) MethodHandles.publicLookup()
+                    .findVirtual(SharedResource.class, "getResourceLock", MethodType.methodType(ResourceLock.class))
+                    .bindTo(resource)
+                    .invokeExact();
+            }
+        } catch (Throwable ex) {
+            throw new IllegalStateException("Unable to find suitable ResourceLock::getResourceLock", ex);
+        }
+    }
+
     @Override
     public Task dependsOn(Object... dependencies) {
         super.dependsOn(dependencies);
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClusterConfiguration.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClusterConfiguration.java
index b27f205291269..22c4185a39a98 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClusterConfiguration.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClusterConfiguration.java
@@ -36,7 +36,6 @@
 import org.gradle.api.file.RegularFile;
 import org.gradle.api.logging.Logging;
 import org.gradle.api.provider.Provider;
-import org.slf4j.Logger;
 
 import java.io.File;
 import java.util.LinkedHashMap;
@@ -47,6 +46,8 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import org.slf4j.Logger;
+
 public interface TestClusterConfiguration {
 
     void setVersion(String version);
@@ -55,6 +56,8 @@ public interface TestClusterConfiguration {
 
     void setTestDistribution(TestDistribution distribution);
 
+    void extension(boolean extensionsEnabled);
+
     void plugin(Provider<RegularFile> plugin);
 
     void plugin(String pluginProjectPath);
@@ -105,6 +108,8 @@ public interface TestClusterConfiguration {
 
     void setPreserveDataDir(boolean preserveDataDir);
 
+    void setSecure(boolean secure);
+
     void freeze();
 
     void start();
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClustersPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClustersPlugin.java
index 2ef14a39b6669..b8ba1e6a90976 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClustersPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestClustersPlugin.java
@@ -57,6 +57,7 @@
 import org.gradle.api.tasks.TaskState;
 
 import javax.inject.Inject;
+
 import java.io.File;
 
 import static org.opensearch.gradle.util.GradleUtils.noop;
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestExtensionsList.java b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestExtensionsList.java
new file mode 100644
index 0000000000000..ea601e26672a2
--- /dev/null
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testclusters/TestExtensionsList.java
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.testclusters;
+
+import java.util.List;
+
+public class TestExtensionsList {
+    private List<ExtensionsProperties> extensions;
+
+    public TestExtensionsList(List<ExtensionsProperties> extensionsList) {
+        extensions = extensionsList;
+    }
+
+    public List<ExtensionsProperties> getExtensions() {
+        return extensions;
+    }
+
+    public void setExtensions(List<ExtensionsProperties> extensionsList) {
+        extensions = extensionsList;
+    }
+}
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/testfixtures/TestFixturesPlugin.java b/buildSrc/src/main/java/org/opensearch/gradle/testfixtures/TestFixturesPlugin.java
index ae1db26fbc48d..3aba941875115 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/testfixtures/TestFixturesPlugin.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/testfixtures/TestFixturesPlugin.java
@@ -37,6 +37,8 @@
 import com.avast.gradle.dockercompose.tasks.ComposeDown;
 import com.avast.gradle.dockercompose.tasks.ComposePull;
 import com.avast.gradle.dockercompose.tasks.ComposeUp;
+
+import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.SystemPropertyCommandLineArgumentProvider;
 import org.opensearch.gradle.docker.DockerSupportPlugin;
 import org.opensearch.gradle.docker.DockerSupportService;
@@ -57,17 +59,17 @@
 import org.gradle.api.tasks.TaskContainer;
 import org.gradle.api.tasks.TaskProvider;
 import org.gradle.api.tasks.testing.Test;
-import org.apache.tools.ant.taskdefs.condition.Os;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.function.BiConsumer;
 import java.util.Optional;
+import java.util.function.BiConsumer;
 
 public class TestFixturesPlugin implements Plugin<Project> {
 
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/util/GradleUtils.java b/buildSrc/src/main/java/org/opensearch/gradle/util/GradleUtils.java
index 054f01788d126..031fee2d1127f 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/util/GradleUtils.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/util/GradleUtils.java
@@ -40,7 +40,7 @@
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.plugins.JavaBasePlugin;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.provider.Provider;
 import org.gradle.api.services.BuildService;
 import org.gradle.api.services.BuildServiceRegistration;
@@ -68,7 +68,7 @@ public static <T> Action<T> noop() {
     }
 
     public static SourceSetContainer getJavaSourceSets(Project project) {
-        return project.getConvention().getPlugin(JavaPluginConvention.class).getSourceSets();
+        return project.getExtensions().getByType(JavaPluginExtension.class).getSourceSets();
     }
 
     public static <T extends Task> TaskProvider<T> maybeRegister(TaskContainer tasks, String name, Class<T> clazz, Action<T> action) {
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/util/Util.java b/buildSrc/src/main/java/org/opensearch/gradle/util/Util.java
index 71b1e5040340d..a2fd1e247b660 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/util/Util.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/util/Util.java
@@ -37,11 +37,12 @@
 import org.gradle.api.GradleException;
 import org.gradle.api.Project;
 import org.gradle.api.file.FileTree;
-import org.gradle.api.plugins.JavaPluginConvention;
+import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.api.tasks.util.PatternFilterable;
 
 import javax.annotation.Nullable;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -149,7 +150,7 @@ public static FileTree getJavaTestAndMainSourceResources(Project project, Action
      * @return An Optional that contains the Java test SourceSet if it exists.
      */
     public static Optional<SourceSet> getJavaTestSourceSet(Project project) {
-        return project.getConvention().findPlugin(JavaPluginConvention.class) == null
+        return project.getExtensions().findByType(JavaPluginExtension.class) == null
             ? Optional.empty()
             : Optional.ofNullable(GradleUtils.getJavaSourceSets(project).findByName(SourceSet.TEST_SOURCE_SET_NAME));
     }
@@ -159,7 +160,7 @@ public static Optional<SourceSet> getJavaTestSourceSet(Project project) {
      * @return An Optional that contains the Java main SourceSet if it exists.
      */
     public static Optional<SourceSet> getJavaMainSourceSet(Project project) {
-        return project.getConvention().findPlugin(JavaPluginConvention.class) == null
+        return project.getExtensions().findByType(JavaPluginExtension.class) == null
             ? Optional.empty()
             : Optional.ofNullable(GradleUtils.getJavaSourceSets(project).findByName(SourceSet.MAIN_SOURCE_SET_NAME));
     }
diff --git a/buildSrc/src/main/java/org/opensearch/gradle/vagrant/VagrantMachine.java b/buildSrc/src/main/java/org/opensearch/gradle/vagrant/VagrantMachine.java
index 75827922fa007..2d71b9361963b 100644
--- a/buildSrc/src/main/java/org/opensearch/gradle/vagrant/VagrantMachine.java
+++ b/buildSrc/src/main/java/org/opensearch/gradle/vagrant/VagrantMachine.java
@@ -43,6 +43,7 @@
 import org.gradle.internal.logging.progress.ProgressLoggerFactory;
 
 import javax.inject.Inject;
+
 import java.io.File;
 import java.io.OutputStream;
 import java.nio.file.Paths;
diff --git a/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.jre-download.properties b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.jre-download.properties
new file mode 100644
index 0000000000000..e9253488ffbeb
--- /dev/null
+++ b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.jre-download.properties
@@ -0,0 +1,12 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+# Modifications Copyright OpenSearch Contributors. See
+# GitHub history for details.
+#
+
+implementation-class=org.opensearch.gradle.JreDownloadPlugin
diff --git a/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.optional-dependencies.properties b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.optional-dependencies.properties
new file mode 100644
index 0000000000000..8b6f6f307cd5d
--- /dev/null
+++ b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.optional-dependencies.properties
@@ -0,0 +1,12 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+# Modifications Copyright OpenSearch Contributors. See
+# GitHub history for details.
+#
+
+implementation-class=org.opensearch.gradle.plugin.OptionalDependenciesPlugin
diff --git a/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.pluginzip.properties b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.pluginzip.properties
new file mode 100644
index 0000000000000..600218ff76835
--- /dev/null
+++ b/buildSrc/src/main/resources/META-INF/gradle-plugins/opensearch.pluginzip.properties
@@ -0,0 +1 @@
+implementation-class=org.opensearch.gradle.pluginzip.Publish
diff --git a/buildSrc/src/main/resources/deb/postinst.ftl b/buildSrc/src/main/resources/deb/postinst.ftl
index 605f620e16444..1fe98263a0fdf 100644
--- a/buildSrc/src/main/resources/deb/postinst.ftl
+++ b/buildSrc/src/main/resources/deb/postinst.ftl
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash -e
+#!/usr/bin/env bash
+set -e -o pipefail
 <% commands.each {command -> %><%= command %><% } %>
diff --git a/buildSrc/src/main/resources/deb/preinst.ftl b/buildSrc/src/main/resources/deb/preinst.ftl
index 605f620e16444..1fe98263a0fdf 100644
--- a/buildSrc/src/main/resources/deb/preinst.ftl
+++ b/buildSrc/src/main/resources/deb/preinst.ftl
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash -e
+#!/usr/bin/env bash
+set -e -o pipefail
 <% commands.each {command -> %><%= command %><% } %>
diff --git a/buildSrc/src/main/resources/eclipse.settings/org.eclipse.core.resources.prefs b/buildSrc/src/main/resources/eclipse.settings/org.eclipse.core.resources.prefs
index 6fd0a9aab1327..29abf99956411 100644
--- a/buildSrc/src/main/resources/eclipse.settings/org.eclipse.core.resources.prefs
+++ b/buildSrc/src/main/resources/eclipse.settings/org.eclipse.core.resources.prefs
@@ -3,4 +3,4 @@ encoding//src/main/java=UTF-8
 encoding//src/main/resources=UTF-8
 encoding//src/test/java=UTF-8
 encoding//src/test/resources=UTF-8
-encoding/<project>=UTF-8
\ No newline at end of file
+encoding/<project>=UTF-8
diff --git a/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt b/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
index 1e4e669e4722f..f9f24fd1e2367 100644
--- a/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
+++ b/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
@@ -50,6 +50,7 @@ java.nio.channels.SocketChannel#connect(java.net.SocketAddress)
 java.lang.Boolean#getBoolean(java.lang.String)
 
 org.apache.lucene.util.IOUtils @ use @org.opensearch.core.internal.io instead
+org.apache.lucene.util.SetOnce @ use @org.opensearch.common.SetOnce instead
 
 @defaultMessage use executors from org.opensearch.common.util.concurrent.OpenSearchExecutors instead which will properly bubble up Errors
 java.util.concurrent.AbstractExecutorService#<init>()
diff --git a/buildSrc/src/main/resources/forbidden/opensearch-test-signatures.txt b/buildSrc/src/main/resources/forbidden/opensearch-test-signatures.txt
index aeb5e25decf62..43568b3209baf 100644
--- a/buildSrc/src/main/resources/forbidden/opensearch-test-signatures.txt
+++ b/buildSrc/src/main/resources/forbidden/opensearch-test-signatures.txt
@@ -19,11 +19,10 @@ com.carrotsearch.randomizedtesting.annotations.Seed @ Don't commit hardcoded see
 com.carrotsearch.randomizedtesting.annotations.Repeat @ Don't commit hardcoded repeats
 
 org.apache.lucene.codecs.Codec#setDefault(org.apache.lucene.codecs.Codec) @ Use the SuppressCodecs("*") annotation instead
-org.apache.lucene.tests.util.LuceneTestCase$Slow @ Don't write slow tests
 org.junit.Ignore @ Use AwaitsFix instead
 org.apache.lucene.tests.util.LuceneTestCase$Nightly @ We don't run nightly tests at this point!
 com.carrotsearch.randomizedtesting.annotations.Nightly @ We don't run nightly tests at this point!
 
 org.junit.Test @defaultMessage Just name your test method testFooBar
 
-java.lang.Math#random() @ Use one of the various randomization methods from LuceneTestCase or ESTestCase for reproducibility
+java.lang.Math#random() @ Use one of the various randomization methods from LuceneTestCase or OpenSearchTestCase for reproducibility
diff --git a/buildSrc/src/main/resources/minimumGradleVersion b/buildSrc/src/main/resources/minimumGradleVersion
index ba92e72f5775b..815da58b7a9ed 100644
--- a/buildSrc/src/main/resources/minimumGradleVersion
+++ b/buildSrc/src/main/resources/minimumGradleVersion
@@ -1 +1 @@
-6.6.1
\ No newline at end of file
+7.4.1
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/ArchitectureTests.java b/buildSrc/src/test/java/org/opensearch/gradle/ArchitectureTests.java
new file mode 100644
index 0000000000000..2df8c1995c834
--- /dev/null
+++ b/buildSrc/src/test/java/org/opensearch/gradle/ArchitectureTests.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle;
+
+import org.opensearch.gradle.test.GradleUnitTestCase;
+
+public class ArchitectureTests extends GradleUnitTestCase {
+
+    final String architecture = System.getProperty("os.arch", "");
+
+    public void testCurrentArchitecture() {
+        assertEquals(Architecture.X64, currentArchitecture("amd64"));
+        assertEquals(Architecture.X64, currentArchitecture("x86_64"));
+        assertEquals(Architecture.ARM64, currentArchitecture("aarch64"));
+        assertEquals(Architecture.S390X, currentArchitecture("s390x"));
+        assertEquals(Architecture.PPC64LE, currentArchitecture("ppc64le"));
+    }
+
+    public void testInvalidCurrentArchitecture() {
+        assertThrows("can not determine architecture from [", IllegalArgumentException.class, () -> currentArchitecture("fooBar64"));
+    }
+
+    /**
+     * Determines the return value of {@link Architecture#current()} based on a string representing a potential OS Architecture.
+     *
+     * @param osArchToTest  An expected value of the {@code os.arch} system property on another architecture.
+     * @return the value of the {@link Architecture} enum which would have resulted with the given value.
+     * @throws IllegalArgumentException if the string is not mapped to a value of the {@link Architecture} enum.
+     */
+    private Architecture currentArchitecture(String osArchToTest) throws IllegalArgumentException {
+        // Test new architecture
+        System.setProperty("os.arch", osArchToTest);
+        try {
+            return Architecture.current();
+        } finally {
+            // Restore actual architecture property value
+            System.setProperty("os.arch", this.architecture);
+        }
+    }
+}
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/ConcatFilesTaskTests.java b/buildSrc/src/test/java/org/opensearch/gradle/ConcatFilesTaskTests.java
index 3b9c1c81e0345..0484939ca4698 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/ConcatFilesTaskTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/ConcatFilesTaskTests.java
@@ -31,16 +31,16 @@
 
 package org.opensearch.gradle;
 
+import org.opensearch.gradle.test.GradleUnitTestCase;
+import org.gradle.api.Project;
+import org.gradle.testfixtures.ProjectBuilder;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.Arrays;
 
-import org.opensearch.gradle.test.GradleUnitTestCase;
-import org.gradle.api.Project;
-import org.gradle.testfixtures.ProjectBuilder;
-
 public class ConcatFilesTaskTests extends GradleUnitTestCase {
 
     public void testHeaderAdded() throws IOException {
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/DistributionDownloadPluginTests.java b/buildSrc/src/test/java/org/opensearch/gradle/DistributionDownloadPluginTests.java
index 446c94acc7ad4..514e169700fd9 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/DistributionDownloadPluginTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/DistributionDownloadPluginTests.java
@@ -32,19 +32,20 @@
 
 package org.opensearch.gradle;
 
-import org.gradle.api.internal.artifacts.repositories.DefaultIvyArtifactRepository;
 import org.opensearch.gradle.OpenSearchDistribution.Platform;
 import org.opensearch.gradle.OpenSearchDistribution.Type;
 import org.opensearch.gradle.info.BuildParams;
 import org.opensearch.gradle.test.GradleUnitTestCase;
 import org.gradle.api.NamedDomainObjectContainer;
 import org.gradle.api.Project;
+import org.gradle.api.internal.artifacts.repositories.DefaultIvyArtifactRepository;
 import org.gradle.testfixtures.ProjectBuilder;
 
 import java.io.File;
 import java.util.Arrays;
 import java.util.TreeSet;
 
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.core.StringContains.containsString;
 
 public class DistributionDownloadPluginTests extends GradleUnitTestCase {
@@ -76,7 +77,14 @@ public class DistributionDownloadPluginTests extends GradleUnitTestCase {
     );
 
     public void testVersionDefault() {
-        OpenSearchDistribution distro = checkDistro(createProject(null, false), "testdistro", null, Type.ARCHIVE, Platform.LINUX, true);
+        OpenSearchDistribution distro = checkDistro(
+            createProject(null, false),
+            "testdistro",
+            null,
+            Type.ARCHIVE,
+            Platform.LINUX,
+            JavaPackageType.JDK
+        );
         assertEquals(distro.getVersion(), VersionProperties.getOpenSearch());
     }
 
@@ -140,18 +148,32 @@ public void testBadVersionFormat() {
             "badversion",
             Type.ARCHIVE,
             Platform.LINUX,
-            true,
+            JavaPackageType.JDK,
             "Invalid version format: 'badversion'"
         );
     }
 
     public void testTypeDefault() {
-        OpenSearchDistribution distro = checkDistro(createProject(null, false), "testdistro", "5.0.0", null, Platform.LINUX, true);
+        OpenSearchDistribution distro = checkDistro(
+            createProject(null, false),
+            "testdistro",
+            "5.0.0",
+            null,
+            Platform.LINUX,
+            JavaPackageType.JDK
+        );
         assertEquals(distro.getType(), Type.ARCHIVE);
     }
 
     public void testPlatformDefault() {
-        OpenSearchDistribution distro = checkDistro(createProject(null, false), "testdistro", "5.0.0", Type.ARCHIVE, null, true);
+        OpenSearchDistribution distro = checkDistro(
+            createProject(null, false),
+            "testdistro",
+            "5.0.0",
+            Type.ARCHIVE,
+            null,
+            JavaPackageType.JDK
+        );
         assertEquals(distro.getPlatform(), OpenSearchDistribution.CURRENT_PLATFORM);
     }
 
@@ -168,8 +190,15 @@ public void testPlatformForIntegTest() {
     }
 
     public void testBundledJdkDefault() {
-        OpenSearchDistribution distro = checkDistro(createProject(null, false), "testdistro", "5.0.0", Type.ARCHIVE, Platform.LINUX, true);
-        assertTrue(distro.getBundledJdk());
+        OpenSearchDistribution distro = checkDistro(
+            createProject(null, false),
+            "testdistro",
+            "5.0.0",
+            Type.ARCHIVE,
+            Platform.LINUX,
+            JavaPackageType.JDK
+        );
+        assertThat(distro.getBundledJdk(), equalTo(JavaPackageType.JDK));
     }
 
     public void testBundledJdkForIntegTest() {
@@ -179,7 +208,7 @@ public void testBundledJdkForIntegTest() {
             "5.0.0",
             Type.INTEG_TEST_ZIP,
             null,
-            true,
+            JavaPackageType.JDK,
             "bundledJdk cannot be set on opensearch distribution [testdistro]"
         );
     }
@@ -195,7 +224,7 @@ public void testLocalCurrentVersionIntegTestZip() {
 
     public void testLocalCurrentVersionArchives() {
         for (Platform platform : Platform.values()) {
-            for (boolean bundledJdk : new boolean[] { true, false }) {
+            for (JavaPackageType bundledJdk : JavaPackageType.values()) {
                 for (Architecture architecture : Architecture.values()) {
                     // create a new project in each iteration, so that we know we are resolving the only additional project being created
                     Project project = createProject(BWC_MINOR, true);
@@ -221,7 +250,7 @@ public void testLocalCurrentVersionArchives() {
 
     public void testLocalCurrentVersionPackages() {
         for (Type packageType : new Type[] { Type.RPM, Type.DEB }) {
-            for (boolean bundledJdk : new boolean[] { true, false }) {
+            for (JavaPackageType bundledJdk : JavaPackageType.values()) {
                 Project project = createProject(BWC_MINOR, true);
                 String projectName = projectName(packageType.toString(), bundledJdk);
                 Project packageProject = ProjectBuilder.builder().withParent(packagesProject).withName(projectName).build();
@@ -236,7 +265,7 @@ public void testLocalCurrentVersionPackages() {
     public void testLocalBwcArchives() {
         for (Platform platform : Platform.values()) {
             // note: no non bundled jdk for bwc
-            String configName = projectName(platform.toString(), true);
+            String configName = projectName(platform.toString(), JavaPackageType.JDK);
             configName += (platform == Platform.WINDOWS ? "-zip" : "-tar");
 
             checkBwc("minor", configName, BWC_MINOR_VERSION, Type.ARCHIVE, platform, BWC_MINOR, true);
@@ -249,7 +278,7 @@ public void testLocalBwcArchives() {
     public void testLocalBwcPackages() {
         for (Type packageType : new Type[] { Type.RPM, Type.DEB }) {
             // note: no non bundled jdk for bwc
-            String configName = projectName(packageType.toString(), true);
+            String configName = projectName(packageType.toString(), JavaPackageType.JDK);
 
             checkBwc("minor", configName, BWC_MINOR_VERSION, packageType, null, BWC_MINOR, true);
             checkBwc("staged", configName, BWC_STAGED_VERSION, packageType, null, BWC_STAGED, true);
@@ -264,7 +293,7 @@ private void assertDistroError(
         String version,
         Type type,
         Platform platform,
-        Boolean bundledJdk,
+        JavaPackageType bundledJdk,
         String message
     ) {
         IllegalArgumentException e = expectThrows(
@@ -280,7 +309,7 @@ private OpenSearchDistribution createDistro(
         String version,
         Type type,
         Platform platform,
-        Boolean bundledJdk
+        JavaPackageType bundledJdk
     ) {
         NamedDomainObjectContainer<OpenSearchDistribution> distros = DistributionDownloadPlugin.getContainer(project);
         return distros.create(name, distro -> {
@@ -306,7 +335,7 @@ private OpenSearchDistribution checkDistro(
         String version,
         Type type,
         Platform platform,
-        Boolean bundledJdk
+        JavaPackageType bundledJdk
     ) {
         OpenSearchDistribution distribution = createDistro(project, name, version, type, platform, bundledJdk);
         distribution.finalizeValues();
@@ -332,7 +361,8 @@ private void checkBwc(
         Project archiveProject = ProjectBuilder.builder().withParent(bwcProject).withName(projectName).build();
         archiveProject.getConfigurations().create(config);
         archiveProject.getArtifacts().add(config, new File("doesnotmatter"));
-        createDistro(project, "distro", version.toString(), type, platform, true);
+        final OpenSearchDistribution distro = createDistro(project, "distro", version.toString(), type, platform, JavaPackageType.JDK);
+        distro.setArchitecture(Architecture.current());
         checkPlugin(project);
     }
 
@@ -351,7 +381,7 @@ private Project createProject(BwcVersions bwcVersions, boolean isInternal) {
         return project;
     }
 
-    private static String projectName(String base, boolean bundledJdk) {
-        return bundledJdk ? base : ("no-jdk-" + base);
+    private static String projectName(String base, JavaPackageType bundledJdk) {
+        return (bundledJdk == JavaPackageType.JDK) ? base : ((bundledJdk == JavaPackageType.NONE) ? ("no-jdk-" + base) : "jre-" + base);
     }
 }
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/EmptyDirTaskTests.java b/buildSrc/src/test/java/org/opensearch/gradle/EmptyDirTaskTests.java
index b4eae42c625ac..ad5b8385abaf8 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/EmptyDirTaskTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/EmptyDirTaskTests.java
@@ -31,15 +31,19 @@
 
 package org.opensearch.gradle;
 
-import java.io.File;
-import java.io.IOException;
-
 import com.carrotsearch.randomizedtesting.RandomizedTest;
+
 import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.test.GradleUnitTestCase;
 import org.gradle.api.Project;
 import org.gradle.testfixtures.ProjectBuilder;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+
 public class EmptyDirTaskTests extends GradleUnitTestCase {
 
     public void testCreateEmptyDir() throws Exception {
@@ -64,7 +68,11 @@ public void testCreateEmptyDir() throws Exception {
     }
 
     public void testCreateEmptyDirNoPermissions() throws Exception {
-        RandomizedTest.assumeFalse("Functionality is Unix specific", Os.isFamily(Os.FAMILY_WINDOWS));
+        // Test depends on Posix file permissions
+        RandomizedTest.assumeFalse("Functionality is Unix-like OS specific", Os.isFamily(Os.FAMILY_WINDOWS));
+        // Java's Files.setPosixFilePermissions is a NOOP inside a Docker container as
+        // files are created by default with UID and GID = 0 (root).
+        RandomizedTest.assumeFalse("Functionality doesn't work in Docker", isRunningInDocker());
 
         Project project = ProjectBuilder.builder().build();
         EmptyDirTask emptyDirTask = project.getTasks().create("emptyDirTask", EmptyDirTask.class);
@@ -92,4 +100,20 @@ private File getNewNonExistingTempFolderFile(Project project) throws IOException
         return newEmptyFolder;
     }
 
+    private static boolean isRunningInDocker() {
+        // Only reliable existing method but may be removed in future
+        if (new File("/.dockerenv").exists()) {
+            return true;
+        }
+        try {
+            // Backup 1: look for 'docker' in one of the paths in /proc/1/cgroup
+            if (Files.lines(Path.of("/proc/1/cgroup")).anyMatch(line -> line.contains("docker"))) {
+                return true;
+            }
+            // Backup 2: look for 'docker' in overlay fs
+            return Files.lines(Path.of("/proc/1/mounts")).anyMatch(line -> line.startsWith("overlay") && line.contains("docker"));
+        } catch (InvalidPathException | IOException e) {
+            return false;
+        }
+    }
 }
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/JdkDownloadPluginTests.java b/buildSrc/src/test/java/org/opensearch/gradle/JdkDownloadPluginTests.java
index 4dcc65cca4c62..bb394cf51429f 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/JdkDownloadPluginTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/JdkDownloadPluginTests.java
@@ -38,6 +38,8 @@
 import org.gradle.testfixtures.ProjectBuilder;
 import org.junit.BeforeClass;
 
+import java.util.UUID;
+
 import static org.hamcrest.CoreMatchers.equalTo;
 
 public class JdkDownloadPluginTests extends GradleUnitTestCase {
@@ -108,7 +110,7 @@ public void testUnknownArchitecture() {
             "11.0.2+33",
             "linux",
             "unknown",
-            "unknown architecture [unknown] for jdk [testjdk], must be one of [aarch64, x64]"
+            "unknown architecture [unknown] for jdk [testjdk], must be one of [aarch64, x64, s390x, ppc64le]"
         );
     }
 
@@ -148,7 +150,8 @@ private void createJdk(Project project, String name, String vendor, String versi
     }
 
     private Project createProject() {
-        Project project = ProjectBuilder.builder().withParent(rootProject).build();
+        final String name = UUID.randomUUID().toString();
+        Project project = ProjectBuilder.builder().withName(name).withParent(rootProject).build();
         project.getPlugins().apply("opensearch.jdk-download");
         return project;
     }
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/plugin/OptionalDependenciesPluginTests.java b/buildSrc/src/test/java/org/opensearch/gradle/plugin/OptionalDependenciesPluginTests.java
new file mode 100644
index 0000000000000..76b669a73610e
--- /dev/null
+++ b/buildSrc/src/test/java/org/opensearch/gradle/plugin/OptionalDependenciesPluginTests.java
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.plugin;
+
+import org.apache.maven.model.Dependency;
+import org.apache.maven.model.Model;
+import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
+import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
+import org.opensearch.gradle.test.GradleUnitTestCase;
+import org.gradle.testkit.runner.BuildResult;
+import org.gradle.testkit.runner.GradleRunner;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Optional;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.gradle.testkit.runner.TaskOutcome.SUCCESS;
+
+public class OptionalDependenciesPluginTests extends GradleUnitTestCase {
+    private TemporaryFolder projectDir;
+
+    @Before
+    public void setUp() throws Exception {
+        projectDir = new TemporaryFolder();
+        projectDir.create();
+    }
+
+    @After
+    public void tearDown() {
+        projectDir.delete();
+    }
+
+    public void testApply() throws FileNotFoundException, IOException, XmlPullParserException {
+        final File mavenRepoDir = new File(projectDir.getRoot(), "mavenrepo");
+
+        try (InputStream in = getClass().getClassLoader().getResourceAsStream("plugin/optional-dependencies.gradle")) {
+            try (OutputStream out = new FileOutputStream(projectDir.newFile("build.gradle"))) {
+                in.transferTo(out);
+            }
+        }
+
+        GradleRunner runner = GradleRunner.create()
+            .forwardOutput()
+            .withPluginClasspath()
+            .withArguments("publish", "-PrepoUrl=" + mavenRepoDir.toURI().toURL())
+            .withProjectDir(projectDir.getRoot());
+
+        BuildResult result = runner.build();
+        assertEquals(SUCCESS, result.task(":" + "publish").getOutcome());
+
+        final String name = projectDir.getRoot().getName();
+        assertDependency(mavenRepoDir, name);
+    }
+
+    private void assertDependency(File repoUrl, String name) throws FileNotFoundException, IOException, XmlPullParserException {
+        final File pom = new File(repoUrl, "org/custom/group/" + name + "/1.0.0/" + name + "-1.0.0.pom");
+        assertThat(pom.exists(), is(true));
+
+        final MavenXpp3Reader reader = new MavenXpp3Reader();
+        final Model model = reader.read(new FileReader(pom));
+
+        final Optional<Dependency> dependecyOpt = model.getDependencies()
+            .stream()
+            .filter(d -> d.getArtifactId().equals("commons-lang3"))
+            .findAny();
+
+        assertThat(dependecyOpt.isPresent(), is(true));
+        assertThat(dependecyOpt.get().isOptional(), is(true));
+    }
+}
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/plugin/PluginBuildPluginTests.java b/buildSrc/src/test/java/org/opensearch/gradle/plugin/PluginBuildPluginTests.java
index 9ed0e3e494992..fa0693a258222 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/plugin/PluginBuildPluginTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/plugin/PluginBuildPluginTests.java
@@ -36,13 +36,15 @@
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.internal.project.ProjectInternal;
+import org.gradle.api.tasks.bundling.AbstractArchiveTask;
 import org.gradle.testfixtures.ProjectBuilder;
 import org.junit.Before;
 import org.junit.Ignore;
-import org.mockito.Mockito;
 
 import java.util.stream.Collectors;
 
+import org.mockito.Mockito;
+
 public class PluginBuildPluginTests extends GradleUnitTestCase {
 
     private Project project;
@@ -64,6 +66,10 @@ public void testApply() {
         assertNotNull("plugin extensions has the right type", project.getExtensions().findByType(PluginPropertiesExtension.class));
 
         assertNull("plugin should not create the integTest task", project.getTasks().findByName("integTest"));
+        project.getTasks().withType(AbstractArchiveTask.class).forEach(t -> {
+            assertFalse(String.format("task '%s' should not preserve timestamps", t.getName()), t.isPreserveFileTimestamps());
+            assertTrue(String.format("task '%s' should have reproducible file order", t.getName()), t.isReproducibleFileOrder());
+        });
     }
 
     @Ignore("https://github.com/elastic/elasticsearch/issues/47123")
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/pluginzip/PublishTests.java b/buildSrc/src/test/java/org/opensearch/gradle/pluginzip/PublishTests.java
new file mode 100644
index 0000000000000..5c26472cbd33e
--- /dev/null
+++ b/buildSrc/src/test/java/org/opensearch/gradle/pluginzip/PublishTests.java
@@ -0,0 +1,590 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gradle.pluginzip;
+
+import org.apache.maven.model.Model;
+import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
+import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
+import org.opensearch.gradle.test.GradleUnitTestCase;
+import org.gradle.api.Project;
+import org.gradle.testfixtures.ProjectBuilder;
+import org.gradle.testkit.runner.BuildResult;
+import org.gradle.testkit.runner.GradleRunner;
+import org.gradle.testkit.runner.UnexpectedBuildFailure;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+
+import static org.gradle.testkit.runner.TaskOutcome.SUCCESS;
+
+public class PublishTests extends GradleUnitTestCase {
+    private TemporaryFolder projectDir;
+    private static final String TEMPLATE_RESOURCE_FOLDER = "pluginzip";
+    private final String PROJECT_NAME = "sample-plugin";
+    private final String ZIP_PUBLISH_TASK = "publishPluginZipPublicationToZipStagingRepository";
+
+    @Before
+    public void setUp() throws IOException {
+        projectDir = new TemporaryFolder();
+        projectDir.create();
+    }
+
+    @After
+    public void tearDown() {
+        projectDir.delete();
+    }
+
+    /**
+     * This test is used to verify that adding the 'opensearch.pluginzip' to the project
+     * adds some other transitive plugins and tasks under the hood. This is basically
+     * a behavioral test of the {@link Publish#apply(Project)} method.
+     *
+     * This is equivalent of having a build.gradle script with just the following section:
+     * <pre>
+     *     plugins {
+     *       id 'opensearch.pluginzip'
+     *     }
+     * </pre>
+     */
+    @Test
+    public void applyZipPublicationPluginNoConfig() {
+        // All we do here is creating an empty project and applying the Publish plugin.
+        Project project = ProjectBuilder.builder().build();
+        project.getPluginManager().apply(Publish.class);
+
+        // WARNING: =====================================================================
+        // All the following tests will work only before the gradle project is evaluated.
+        // There are some methods that will cause the project to be evaluated, such as:
+        // project.getTasksByName()
+        // After the project is evaluated there are more tasks found in the project, like
+        // the [assemble, build, ...] and other standard tasks.
+        // This can potentially break in future gradle versions (?)
+        // ===============================================================================
+
+        assertEquals(
+            "The Publish plugin is applied which adds total of five tasks from Nebula and MavenPublishing plugins.",
+            5,
+            project.getTasks().size()
+        );
+
+        // Tasks applied from "com.netflix.nebula.maven-base-publish"
+        assertTrue(
+            project.getTasks()
+                .findByName("generateMetadataFileForNebulaPublication") instanceof org.gradle.api.publish.tasks.GenerateModuleMetadata
+        );
+        assertTrue(
+            project.getTasks()
+                .findByName("generatePomFileForNebulaPublication") instanceof org.gradle.api.publish.maven.tasks.GenerateMavenPom
+        );
+        assertTrue(
+            project.getTasks()
+                .findByName("publishNebulaPublicationToMavenLocal") instanceof org.gradle.api.publish.maven.tasks.PublishToMavenLocal
+        );
+
+        // Tasks applied from MavenPublishPlugin
+        assertTrue(project.getTasks().findByName("publishToMavenLocal") instanceof org.gradle.api.DefaultTask);
+        assertTrue(project.getTasks().findByName("publish") instanceof org.gradle.api.DefaultTask);
+
+        // And we miss the pluginzip publication task (because no publishing was defined for it)
+        assertNull(project.getTasks().findByName(ZIP_PUBLISH_TASK));
+
+        // We have the following publishing plugins
+        assertEquals(4, project.getPlugins().size());
+        // ... of the following types:
+        assertNotNull(
+            "Project is expected to have OpenSearch pluginzip Publish plugin",
+            project.getPlugins().findPlugin(org.opensearch.gradle.pluginzip.Publish.class)
+        );
+        assertNotNull(
+            "Project is expected to have MavenPublishPlugin (applied from OpenSearch pluginzip plugin)",
+            project.getPlugins().findPlugin(org.gradle.api.publish.maven.plugins.MavenPublishPlugin.class)
+        );
+        assertNotNull(
+            "Project is expected to have Publishing plugin (applied from MavenPublishPublish plugin)",
+            project.getPlugins().findPlugin(org.gradle.api.publish.plugins.PublishingPlugin.class)
+        );
+        assertNotNull(
+            "Project is expected to have nebula MavenNebulaPublishPlugin plugin (applied from OpenSearch pluginzip plugin)",
+            project.getPlugins().findPlugin(nebula.plugin.publishing.maven.MavenNebulaPublishPlugin.class)
+        );
+    }
+
+    /**
+     * Verify that if the zip publication is configured then relevant tasks are chained correctly.
+     * This test that the dependsOn() is applied correctly.
+     */
+    @Test
+    public void applyZipPublicationPluginWithConfig() throws IOException, URISyntaxException, InterruptedException {
+
+        /* -------------------------------
+        // The ideal approach would be to create a project (via ProjectBuilder) with publishzip plugin,
+        // have it evaluated (API call) and then check if there are tasks that the plugin uses to hookup into
+        // and how these tasks are chained. The problem is that there is a known gradle issue (#20301) that does
+        // not allow for it ATM. If, however, it is fixed in the future the following is the code that can
+        // be used...
+
+        Project project = ProjectBuilder.builder().build();
+        project.getPluginManager().apply(Publish.class);
+        // add publications via API
+
+        // evaluate the project
+        ((DefaultProject)project).evaluate();
+
+        // - Check that "validatePluginZipPom" and/or "publishPluginZipPublicationToZipStagingRepository"
+        //   tasks have dependencies on "generatePomFileForNebulaPublication".
+        // - Check that there is the staging repository added.
+
+        // However, due to known issue(1): https://github.com/gradle/gradle/issues/20301
+        // it is impossible to reach to individual tasks and work with them.
+        // (1): https://docs.gradle.org/7.4/release-notes.html#known-issues
+
+        // I.e.: The following code throws exception, basically any access to individual tasks fails.
+        project.getTasks().getByName("validatePluginZipPom");
+         ------------------------------- */
+
+        // Instead, we run the gradle project via GradleRunner (this way we get fully evaluated project)
+        // and using the minimal possible configuration (missingPOMEntity) we test that as soon as the zip publication
+        // configuration is specified then all the necessary tasks are hooked up and executed correctly.
+        // However, this does not test execution order of the tasks.
+        GradleRunner runner = prepareGradleRunnerFromTemplate("missingPOMEntity.gradle", ZIP_PUBLISH_TASK/*, "-m"*/);
+        BuildResult result = runner.build();
+
+        assertEquals(SUCCESS, result.task(":" + "bundlePlugin").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + "generatePomFileForNebulaPublication").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + "generatePomFileForPluginZipPublication").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+    }
+
+    /**
+     * If the plugin is used but relevant publication is not defined then a message is printed.
+     */
+    @Test
+    public void missingPublications() throws IOException, URISyntaxException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("missingPublications.gradle", "build", "-m");
+        BuildResult result = runner.build();
+
+        assertTrue(result.getOutput().contains("Plugin 'opensearch.pluginzip' is applied but no 'pluginZip' publication is defined."));
+    }
+
+    /**
+     * In OpenSearch 3.x the `project.group` property will be mandatory.
+     * But in 2.x (2.4 and above) the `project.group` property can be empty in which case it falls back to default value.
+     */
+    @Test
+    public void missingGroupValue() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("missingGroupValue.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // Parse the maven file and validate default values
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "org",
+                        "opensearch",
+                        "plugin",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getGroupId(), "org.opensearch.plugin");
+        assertEquals(model.getArtifactId(), PROJECT_NAME);
+    }
+
+    /**
+     * This would be the most common use case where user declares Maven publication entity with minimal info
+     * and the resulting POM file will use artifactId, groupId and version values based on the Gradle project object.
+     */
+    @Test
+    public void useDefaultValues() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("useDefaultValues.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // check if both the zip and pom files have been published to local staging repo
+        assertTrue(
+            new File(
+                projectDir.getRoot(),
+                String.join(
+                    File.separator,
+                    "build",
+                    "local-staging-repo",
+                    "org",
+                    "custom",
+                    "group",
+                    PROJECT_NAME,
+                    "2.0.0.0",
+                    PROJECT_NAME + "-2.0.0.0.pom"
+                )
+            ).exists()
+        );
+        assertTrue(
+            new File(
+                projectDir.getRoot(),
+                String.join(
+                    File.separator,
+                    "build",
+                    "local-staging-repo",
+                    "org",
+                    "custom",
+                    "group",
+                    PROJECT_NAME,
+                    "2.0.0.0",
+                    PROJECT_NAME + "-2.0.0.0.zip"
+                )
+            ).exists()
+        );
+
+        // Parse the maven file and validate default values
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "org",
+                        "custom",
+                        "group",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getGroupId(), "org.custom.group");
+        assertEquals(model.getArtifactId(), PROJECT_NAME);
+        assertNull(model.getName());
+        assertNull(model.getDescription());
+
+        assertEquals(model.getUrl(), "https://github.com/doe/sample-plugin");
+    }
+
+    /**
+     * If the `group` is defined in gradle's allprojects section then it does not have to defined in publications.
+     */
+    @Test
+    public void allProjectsGroup() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("allProjectsGroup.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // Parse the maven file and validate default values
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "org",
+                        "opensearch",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getGroupId(), "org.opensearch");
+    }
+
+    /**
+     * The groupId value can be defined on several levels. This tests that the most internal level outweighs other levels.
+     */
+    @Test
+    public void groupPriorityLevel() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("groupPriorityLevel.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // Parse the maven file and validate default values
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "level",
+                        "3",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getGroupId(), "level.3");
+    }
+
+    /**
+     * In this case the Publication entity is completely missing but still the POM file is generated using the default
+     * values including the groupId and version values obtained from the Gradle project object.
+     */
+    @Test
+    public void missingPOMEntity() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("missingPOMEntity.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // Parse the maven file and validate it
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "org",
+                        "custom",
+                        "group",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+
+        assertEquals(model.getArtifactId(), PROJECT_NAME);
+        assertEquals(model.getGroupId(), "org.custom.group");
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getPackaging(), "zip");
+
+        assertNull(model.getName());
+        assertNull(model.getDescription());
+
+        assertEquals(0, model.getDevelopers().size());
+        assertEquals(0, model.getContributors().size());
+        assertEquals(0, model.getLicenses().size());
+    }
+
+    /**
+     * In some cases we need the POM groupId value to be different from the Gradle "project.group" value hence we
+     * allow for groupId customization (it will override whatever the Gradle "project.group" value is).
+     */
+    @Test
+    public void customizedGroupValue() throws IOException, URISyntaxException, XmlPullParserException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("customizedGroupValue.gradle", "build", ZIP_PUBLISH_TASK);
+        BuildResult result = runner.build();
+
+        /** Check if build and {@value ZIP_PUBLISH_TASK} tasks have run well */
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + ZIP_PUBLISH_TASK).getOutcome());
+
+        // Parse the maven file and validate the groupID
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "I",
+                        "am",
+                        "customized",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+
+        assertEquals(model.getGroupId(), "I.am.customized");
+    }
+
+    /**
+     * If the customized groupId value is invalid (from the Maven POM perspective) then we need to be sure it is
+     * caught and reported properly.
+     */
+    @Test
+    public void customizedInvalidGroupValue() throws IOException, URISyntaxException {
+        GradleRunner runner = prepareGradleRunnerFromTemplate("customizedInvalidGroupValue.gradle", "build", ZIP_PUBLISH_TASK);
+        Exception e = assertThrows(UnexpectedBuildFailure.class, runner::build);
+        assertTrue(
+            e.getMessage().contains("Invalid publication 'pluginZip': groupId ( ) is not a valid Maven identifier ([A-Za-z0-9_\\-.]+).")
+        );
+    }
+
+    /**
+     * This test verifies that use of the pluginZip does not clash with other maven publication plugins.
+     * It covers the case when user calls the "publishToMavenLocal" task.
+     */
+    @Test
+    public void publishToMavenLocal() throws IOException, URISyntaxException, XmlPullParserException {
+        // By default, the "publishToMavenLocal" publishes artifacts to a local m2 repo, typically
+        // found in `~/.m2/repository`. But this is not practical for this unit test at all. We need to point
+        // the 'maven-publish' plugin to a custom m2 repo located in temporary directory associated with this
+        // test case instead.
+        //
+        // According to Gradle documentation this should be possible by proper configuration of the publishing
+        // task (https://docs.gradle.org/current/userguide/publishing_maven.html#publishing_maven:install).
+        // But for some reason this never worked as expected and artifacts created during this test case
+        // were always pushed into the default local m2 repository (ie: `~/.m2/repository`).
+        // The only workaround that seems to work is to pass "-Dmaven.repo.local" property via runner argument.
+        // (Kudos to: https://stackoverflow.com/questions/72265294/gradle-publishtomavenlocal-specify-custom-directory)
+        //
+        // The temporary directory that is used as the local m2 repository is created via in task "prepareLocalMVNRepo".
+        GradleRunner runner = prepareGradleRunnerFromTemplate(
+            "publishToMavenLocal.gradle",
+            String.join(File.separator, "-Dmaven.repo.local=" + projectDir.getRoot(), "build", "local-staging-repo"),
+            "build",
+            "prepareLocalMVNRepo",
+            "publishToMavenLocal"
+        );
+        BuildResult result = runner.build();
+
+        assertEquals(SUCCESS, result.task(":" + "build").getOutcome());
+        assertEquals(SUCCESS, result.task(":" + "publishToMavenLocal").getOutcome());
+
+        // Parse the maven file and validate it
+        MavenXpp3Reader reader = new MavenXpp3Reader();
+        Model model = reader.read(
+            new FileReader(
+                new File(
+                    projectDir.getRoot(),
+                    String.join(
+                        File.separator,
+                        "build",
+                        "local-staging-repo",
+                        "org",
+                        "custom",
+                        "group",
+                        PROJECT_NAME,
+                        "2.0.0.0",
+                        PROJECT_NAME + "-2.0.0.0.pom"
+                    )
+                )
+            )
+        );
+
+        // The "publishToMavenLocal" task will run ALL maven publications, hence we can expect the ZIP publication
+        // present as well: https://docs.gradle.org/current/userguide/publishing_maven.html#publishing_maven:tasks
+        assertEquals(model.getArtifactId(), PROJECT_NAME);
+        assertEquals(model.getGroupId(), "org.custom.group");
+        assertEquals(model.getVersion(), "2.0.0.0");
+        assertEquals(model.getPackaging(), "zip");
+
+        // We have two publications in the build.gradle file, both are "MavenPublication" based.
+        // Both the mavenJava and pluginZip publications publish to the same location (coordinates) and
+        // artifacts (the POM file) overwrite each other. However, we can verify that the Zip plugin is
+        // the last one and "wins" over the mavenJava.
+        assertEquals(model.getDescription(), "pluginZip publication");
+    }
+
+    /**
+     * A helper method for use cases
+     *
+     * @param templateName The name of the file (from "pluginzip" folder) to use as a build.gradle for the test
+     * @param gradleArguments Optional CLI parameters to pass into Gradle runner
+     */
+    private GradleRunner prepareGradleRunnerFromTemplate(String templateName, String... gradleArguments) throws IOException,
+        URISyntaxException {
+        useTemplateFile(projectDir.newFile("build.gradle"), templateName);
+        prepareGradleFilesAndSources();
+
+        GradleRunner runner = GradleRunner.create()
+            .forwardOutput()
+            .withPluginClasspath()
+            .withArguments(gradleArguments)
+            .withProjectDir(projectDir.getRoot());
+
+        return runner;
+    }
+
+    private void prepareGradleFilesAndSources() throws IOException {
+        // A dummy "source" file that is processed with bundlePlugin and put into a ZIP artifact file
+        File bundleFile = new File(projectDir.getRoot(), PROJECT_NAME + "-source.txt");
+        Files.createFile(bundleFile.toPath());
+        // Setting a project name via settings.gradle file
+        writeString(projectDir.newFile("settings.gradle"), "rootProject.name = '" + PROJECT_NAME + "'");
+    }
+
+    private void writeString(File file, String string) throws IOException {
+        try (Writer writer = new FileWriter(file)) {
+            writer.write(string);
+        }
+    }
+
+    /**
+     * Write the content of the "template" file into the target file.
+     * The template file must be located in the {@value TEMPLATE_RESOURCE_FOLDER} folder.
+     * @param targetFile A target file
+     * @param templateFile A name of the template file located under {@value TEMPLATE_RESOURCE_FOLDER} folder
+     */
+    private void useTemplateFile(File targetFile, String templateFile) throws IOException, URISyntaxException {
+
+        URL resource = getClass().getClassLoader().getResource(String.join(File.separator, TEMPLATE_RESOURCE_FOLDER, templateFile));
+        Path resPath = Paths.get(resource.toURI()).toAbsolutePath();
+        List<String> lines = Files.readAllLines(resPath, StandardCharsets.UTF_8);
+
+        try (Writer writer = new FileWriter(targetFile)) {
+            for (String line : lines) {
+                writer.write(line);
+                writer.write(System.lineSeparator());
+            }
+        }
+    }
+
+}
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/precommit/DependencyLicensesTaskTests.java b/buildSrc/src/test/java/org/opensearch/gradle/precommit/DependencyLicensesTaskTests.java
index 6bb6b90116394..bb216b27128e1 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/precommit/DependencyLicensesTaskTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/precommit/DependencyLicensesTaskTests.java
@@ -35,6 +35,7 @@
 import org.gradle.api.Action;
 import org.gradle.api.GradleException;
 import org.gradle.api.Project;
+import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.plugins.JavaPlugin;
@@ -95,7 +96,7 @@ public void givenProjectWithoutLicensesDirButWithDependenciesThenShouldThrowExce
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("does not exist, but there are dependencies"));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
         task.get().checkDependencies();
     }
 
@@ -113,7 +114,7 @@ public void givenProjectWithDependencyButNoShaFileThenShouldReturnException() th
         createFileIn(licensesDir, "groovy-LICENSE.txt", PERMISSIVE_LICENSE_TEXT);
         createFileIn(licensesDir, "groovy-NOTICE.txt", "");
 
-        project.getDependencies().add("compileClasspath", project.getDependencies().localGroovy());
+        project.getDependencies().add("someCompileConfiguration", project.getDependencies().localGroovy());
         task.get().checkDependencies();
     }
 
@@ -122,7 +123,7 @@ public void givenProjectWithDependencyButNoLicenseFileThenShouldReturnException(
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Missing LICENSE for "));
 
-        project.getDependencies().add("compileClasspath", project.getDependencies().localGroovy());
+        project.getDependencies().add("someCompileConfiguration", project.getDependencies().localGroovy());
 
         getLicensesDir(project).mkdir();
         updateShas.updateShas();
@@ -134,7 +135,7 @@ public void givenProjectWithDependencyButNoNoticeFileThenShouldReturnException()
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Missing NOTICE for "));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         createFileIn(getLicensesDir(project), "groovy-LICENSE.txt", PERMISSIVE_LICENSE_TEXT);
 
@@ -147,7 +148,7 @@ public void givenProjectWithStrictDependencyButNoSourcesFileThenShouldReturnExce
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Missing SOURCES for "));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         createFileIn(getLicensesDir(project), "groovy-LICENSE.txt", STRICT_LICENSE_TEXT);
         createFileIn(getLicensesDir(project), "groovy-NOTICE.txt", "");
@@ -158,7 +159,7 @@ public void givenProjectWithStrictDependencyButNoSourcesFileThenShouldReturnExce
 
     @Test
     public void givenProjectWithStrictDependencyAndEverythingInOrderThenShouldReturnSilently() throws Exception {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         createFileIn(getLicensesDir(project), "groovy-LICENSE.txt", STRICT_LICENSE_TEXT);
         createFileIn(getLicensesDir(project), "groovy-NOTICE.txt", "");
@@ -174,7 +175,7 @@ public void givenProjectWithStrictDependencyAndEverythingInOrderThenShouldReturn
 
     @Test
     public void givenProjectWithDependencyAndEverythingInOrderThenShouldReturnSilently() throws Exception {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
 
@@ -187,7 +188,7 @@ public void givenProjectWithALicenseButWithoutTheDependencyThenShouldThrowExcept
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Unused license "));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createAllDefaultDependencyFiles(licensesDir, "groovy", "javaparser-core");
@@ -201,7 +202,7 @@ public void givenProjectWithANoticeButWithoutTheDependencyThenShouldThrowExcepti
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Unused notice "));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createAllDefaultDependencyFiles(licensesDir, "groovy", "javaparser-core");
@@ -215,7 +216,7 @@ public void givenProjectWithAShaButWithoutTheDependencyThenShouldThrowException(
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("Unused sha files found: \n"));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createAllDefaultDependencyFiles(licensesDir, "groovy", "javaparser-core");
@@ -229,7 +230,7 @@ public void givenProjectWithADependencyWithWrongShaThenShouldThrowException() th
         expectedException.expect(GradleException.class);
         expectedException.expectMessage(containsString("SHA has changed! Expected "));
 
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createAllDefaultDependencyFiles(licensesDir, "groovy");
@@ -243,7 +244,7 @@ public void givenProjectWithADependencyWithWrongShaThenShouldThrowException() th
 
     @Test
     public void givenProjectWithADependencyMappingThenShouldReturnSilently() throws Exception {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createAllDefaultDependencyFiles(licensesDir, "groovy", "javaparser");
@@ -258,7 +259,7 @@ public void givenProjectWithADependencyMappingThenShouldReturnSilently() throws
 
     @Test
     public void givenProjectWithAIgnoreShaConfigurationAndNoShaFileThenShouldReturnSilently() throws Exception {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File licensesDir = getLicensesDir(project);
         createFileIn(licensesDir, "groovy-LICENSE.txt", PERMISSIVE_LICENSE_TEXT);
@@ -297,6 +298,11 @@ private Project createProject() {
         Project project = ProjectBuilder.builder().build();
         project.getPlugins().apply(JavaPlugin.class);
 
+        Configuration compileClasspath = project.getConfigurations().getByName("compileClasspath");
+        Configuration someCompileConfiguration = project.getConfigurations().create("someCompileConfiguration");
+        // Declare a configuration that is going to resolve the compile classpath of the application
+        project.getConfigurations().add(compileClasspath.extendsFrom(someCompileConfiguration));
+
         return project;
     }
 
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/precommit/FilePermissionsTaskTests.java b/buildSrc/src/test/java/org/opensearch/gradle/precommit/FilePermissionsTaskTests.java
index f47964dd17a7a..0a8cff734ea97 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/precommit/FilePermissionsTaskTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/precommit/FilePermissionsTaskTests.java
@@ -31,12 +31,8 @@
 
 package org.opensearch.gradle.precommit;
 
-import java.io.File;
-import java.nio.charset.Charset;
-import java.nio.file.Files;
-import java.util.List;
-
 import com.carrotsearch.randomizedtesting.RandomizedTest;
+
 import org.apache.tools.ant.taskdefs.condition.Os;
 import org.opensearch.gradle.test.GradleUnitTestCase;
 import org.gradle.api.GradleException;
@@ -45,6 +41,11 @@
 import org.gradle.testfixtures.ProjectBuilder;
 import org.junit.Assert;
 
+import java.io.File;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.util.List;
+
 public class FilePermissionsTaskTests extends GradleUnitTestCase {
 
     public void testCheckPermissionsWhenAnExecutableFileExists() throws Exception {
diff --git a/buildSrc/src/test/java/org/opensearch/gradle/precommit/UpdateShasTaskTests.java b/buildSrc/src/test/java/org/opensearch/gradle/precommit/UpdateShasTaskTests.java
index a4f3dfb92a04f..2deabb752017a 100644
--- a/buildSrc/src/test/java/org/opensearch/gradle/precommit/UpdateShasTaskTests.java
+++ b/buildSrc/src/test/java/org/opensearch/gradle/precommit/UpdateShasTaskTests.java
@@ -36,6 +36,7 @@
 import org.gradle.api.Action;
 import org.gradle.api.GradleException;
 import org.gradle.api.Project;
+import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.plugins.JavaPlugin;
@@ -86,7 +87,7 @@ public void whenDependencyDoesntExistThenShouldDeleteDependencySha() throws IOEx
 
     @Test
     public void whenDependencyExistsButShaNotThenShouldCreateNewShaFile() throws IOException, NoSuchAlgorithmException {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         getLicensesDir(project).mkdir();
         task.updateShas();
@@ -99,7 +100,7 @@ public void whenDependencyExistsButShaNotThenShouldCreateNewShaFile() throws IOE
 
     @Test
     public void whenDependencyAndWrongShaExistsThenShouldNotOverwriteShaFile() throws IOException, NoSuchAlgorithmException {
-        project.getDependencies().add("compileClasspath", dependency);
+        project.getDependencies().add("someCompileConfiguration", dependency);
 
         File groovyJar = task.getParentTask().getDependencies().getFiles().iterator().next();
         String groovyShaName = groovyJar.getName() + ".sha1";
@@ -122,6 +123,11 @@ private Project createProject() {
         Project project = ProjectBuilder.builder().build();
         project.getPlugins().apply(JavaPlugin.class);
 
+        Configuration compileClasspath = project.getConfigurations().getByName("compileClasspath");
+        Configuration someCompileConfiguration = project.getConfigurations().create("someCompileConfiguration");
+        // Declare a configuration that is going to resolve the compile classpath of the application
+        project.getConfigurations().add(compileClasspath.extendsFrom(someCompileConfiguration));
+
         return project;
     }
 
diff --git a/buildSrc/src/test/resources/plugin/optional-dependencies.gradle b/buildSrc/src/test/resources/plugin/optional-dependencies.gradle
new file mode 100644
index 0000000000000..ebcf758f578d8
--- /dev/null
+++ b/buildSrc/src/test/resources/plugin/optional-dependencies.gradle
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+plugins {
+  id 'java'
+  id 'maven-publish'
+  id 'opensearch.optional-dependencies'
+}
+group = "org.custom.group"
+version = '1.0.0'
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  implementation 'org.apache.commons:commons-lang3:3.3.2', optional
+}
+
+publishing {
+  publications {
+    mavenJava(MavenPublication) {
+      from components.java
+    }
+  }
+  repositories {
+    maven {
+      url "${repoUrl}"
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/allProjectsGroup.gradle b/buildSrc/src/test/resources/pluginzip/allProjectsGroup.gradle
new file mode 100644
index 0000000000000..80638107c86e1
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/allProjectsGroup.gradle
@@ -0,0 +1,28 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+allprojects {
+  group = 'org.opensearch'
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) { publication ->
+      pom {
+        name = "sample-plugin"
+        description = "pluginDescription"
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/customizedGroupValue.gradle b/buildSrc/src/test/resources/pluginzip/customizedGroupValue.gradle
new file mode 100644
index 0000000000000..94f03132faa80
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/customizedGroupValue.gradle
@@ -0,0 +1,44 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) {
+      groupId = "I.am.customized"
+      pom {
+        name = "sample-plugin"
+        description = "pluginDescription"
+        licenses {
+          license {
+            name = "The Apache License, Version 2.0"
+            url = "http://www.apache.org/licenses/LICENSE-2.0.txt"
+          }
+        }
+        developers {
+          developer {
+            name = "John Doe"
+            url = "https://github.com/john-doe/"
+            organization = "Doe.inc"
+            organizationUrl = "https://doe.inc/"
+          }
+        }
+        url = "https://github.com/doe/sample-plugin"
+        scm {
+          url = "https://github.com/doe/sample-plugin"
+        }
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/customizedInvalidGroupValue.gradle b/buildSrc/src/test/resources/pluginzip/customizedInvalidGroupValue.gradle
new file mode 100644
index 0000000000000..6f2abbdacd6d4
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/customizedInvalidGroupValue.gradle
@@ -0,0 +1,44 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) {
+      groupId = " "  // <-- User provides invalid value
+      pom {
+        name = "sample-plugin"
+        description = "pluginDescription"
+        licenses {
+          license {
+            name = "The Apache License, Version 2.0"
+            url = "http://www.apache.org/licenses/LICENSE-2.0.txt"
+          }
+        }
+        developers {
+          developer {
+            name = "John Doe"
+            url = "https://github.com/john-doe/"
+            organization = "Doe.inc"
+            organizationUrl = "https://doe.inc/"
+          }
+        }
+        url = "https://github.com/doe/sample-plugin"
+        scm {
+          url = "https://github.com/doe/sample-plugin"
+        }
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/groupPriorityLevel.gradle b/buildSrc/src/test/resources/pluginzip/groupPriorityLevel.gradle
new file mode 100644
index 0000000000000..4da02c9f191d8
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/groupPriorityLevel.gradle
@@ -0,0 +1,30 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+allprojects {
+  group = 'level.1'
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) { publication ->
+      groupId = "level.2"
+      pom {
+        name = "sample-plugin"
+        description = "pluginDescription"
+        groupId = "level.3"
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/missingGroupValue.gradle b/buildSrc/src/test/resources/pluginzip/missingGroupValue.gradle
new file mode 100644
index 0000000000000..8fcd1d6600b5a
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/missingGroupValue.gradle
@@ -0,0 +1,21 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+//group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) {
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/missingPOMEntity.gradle b/buildSrc/src/test/resources/pluginzip/missingPOMEntity.gradle
new file mode 100644
index 0000000000000..394bc53622769
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/missingPOMEntity.gradle
@@ -0,0 +1,21 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) {
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/missingPublications.gradle b/buildSrc/src/test/resources/pluginzip/missingPublications.gradle
new file mode 100644
index 0000000000000..ba6b33ad86463
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/missingPublications.gradle
@@ -0,0 +1,21 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+//publishing {
+//  publications {
+//    pluginZip(MavenPublication) {
+//    }
+//  }
+//}
diff --git a/buildSrc/src/test/resources/pluginzip/publishToMavenLocal.gradle b/buildSrc/src/test/resources/pluginzip/publishToMavenLocal.gradle
new file mode 100644
index 0000000000000..8d248dbe08a42
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/publishToMavenLocal.gradle
@@ -0,0 +1,47 @@
+plugins {
+  // The java-gradle-plugin adds a new publication called 'pluginMaven' that causes some warnings because it
+  // clashes a bit with other publications defined in this file. If you are running at the --info level then you can
+  // expect some warning like the following:
+  // "Multiple publications with coordinates 'org.custom.group:sample-plugin:2.0.0.0' are published to repository 'mavenLocal'."
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+// A task to prepare directory for a temporary maven local repository
+tasks.register('prepareLocalMVNRepo') {
+  dependsOn ':bundlePlugin'
+  doFirst {
+    File localMVNRepo = new File (layout.buildDirectory.get().getAsFile().getPath(), 'local-staging-repo')
+    System.out.println('Creating temporary folder for mavenLocal repo: '+ localMVNRepo.toString())
+    System.out.println("Success: " + localMVNRepo.mkdir())
+  }
+}
+
+publishing {
+  publications {
+    // Plugin zip publication
+    pluginZip(MavenPublication) {
+      pom {
+        url = 'http://www.example.com/library'
+        description = 'pluginZip publication'
+      }
+    }
+    // Standard maven publication
+    mavenJava(MavenPublication) {
+      pom {
+        url = 'http://www.example.com/library'
+        description = 'mavenJava publication'
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/test/resources/pluginzip/useDefaultValues.gradle b/buildSrc/src/test/resources/pluginzip/useDefaultValues.gradle
new file mode 100644
index 0000000000000..52f1c042fd47c
--- /dev/null
+++ b/buildSrc/src/test/resources/pluginzip/useDefaultValues.gradle
@@ -0,0 +1,43 @@
+plugins {
+  id 'java-gradle-plugin'
+  id 'opensearch.pluginzip'
+}
+
+group="org.custom.group"
+version='2.0.0.0'
+
+// A bundlePlugin task mockup
+tasks.register('bundlePlugin', Zip.class) {
+  archiveFileName = "sample-plugin-${version}.zip"
+  destinationDirectory = layout.buildDirectory.dir('distributions')
+  from layout.projectDirectory.file('sample-plugin-source.txt')
+}
+
+publishing {
+  publications {
+    pluginZip(MavenPublication) {
+      pom {
+//        name = "plugin name"
+//        description = "plugin description"
+        licenses {
+          license {
+            name = "The Apache License, Version 2.0"
+            url = "http://www.apache.org/licenses/LICENSE-2.0.txt"
+          }
+        }
+        developers {
+          developer {
+            name = "John Doe"
+            url = "https://github.com/john-doe/"
+            organization = "Doe.inc"
+            organizationUrl = "https://doe.inc/"
+          }
+        }
+        url = "https://github.com/doe/sample-plugin"
+        scm {
+          url = "https://github.com/doe/sample-plugin"
+        }
+      }
+    }
+  }
+}
diff --git a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/BaseTestCase.java b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/BaseTestCase.java
index 8e06a1cad0241..f285dcbfd3bd2 100644
--- a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/BaseTestCase.java
+++ b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/BaseTestCase.java
@@ -35,10 +35,12 @@
 import com.carrotsearch.randomizedtesting.RandomizedRunner;
 import com.carrotsearch.randomizedtesting.annotations.TestMethodProviders;
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakLingering;
-import junit.framework.AssertionFailedError;
+
 import org.junit.Assert;
 import org.junit.runner.RunWith;
 
+import junit.framework.AssertionFailedError;
+
 @RunWith(RandomizedRunner.class)
 @TestMethodProviders({ JUnit4MethodProvider.class, JUnit3MethodProvider.class })
 @ThreadLeakLingering(linger = 5000) // wait for "Connection worker" to die
diff --git a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/GradleUnitTestCase.java b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/GradleUnitTestCase.java
index a50a14a0ea932..f8032ba53df4c 100644
--- a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/GradleUnitTestCase.java
+++ b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/GradleUnitTestCase.java
@@ -35,6 +35,7 @@
 import com.carrotsearch.randomizedtesting.RandomizedRunner;
 import com.carrotsearch.randomizedtesting.annotations.TestMethodProviders;
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
 import org.junit.runner.RunWith;
 
 @RunWith(RandomizedRunner.class)
diff --git a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/JUnit3MethodProvider.java b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/JUnit3MethodProvider.java
index 0c01b6d519d62..163a903d31832 100644
--- a/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/JUnit3MethodProvider.java
+++ b/buildSrc/src/testFixtures/java/org/opensearch/gradle/test/JUnit3MethodProvider.java
@@ -59,7 +59,7 @@ public Collection<Method> getTestMethods(Class<?> suiteClass, ClassModel classMo
             if (m.getName().startsWith("test")
                 && Modifier.isPublic(m.getModifiers())
                 && !Modifier.isStatic(m.getModifiers())
-                && m.getParameterTypes().length == 0) {
+                && m.getParameterCount() == 0) {
                 result.add(m);
             }
         }
diff --git a/buildSrc/src/testKit/testingConventions/build.gradle b/buildSrc/src/testKit/testingConventions/build.gradle
index 418e833e8cb14..676960bcc8b70 100644
--- a/buildSrc/src/testKit/testingConventions/build.gradle
+++ b/buildSrc/src/testKit/testingConventions/build.gradle
@@ -88,6 +88,3 @@ project(':valid_setup_with_base') {
     }
   }
 }
-
-
-
diff --git a/buildSrc/src/testKit/testingConventions/settings.gradle b/buildSrc/src/testKit/testingConventions/settings.gradle
index c4206edd63ff7..bb64f39e020c5 100644
--- a/buildSrc/src/testKit/testingConventions/settings.gradle
+++ b/buildSrc/src/testKit/testingConventions/settings.gradle
@@ -16,4 +16,4 @@ include 'all_classes_in_tasks'
 include 'not_implementing_base'
 include 'valid_setup_no_base'
 include 'valid_setup_with_base'
-include 'tests_in_main'
\ No newline at end of file
+include 'tests_in_main'
diff --git a/buildSrc/src/testKit/thirdPartyAudit/build.gradle b/buildSrc/src/testKit/thirdPartyAudit/build.gradle
index 41e699db94dcf..553ff5d8e6ed2 100644
--- a/buildSrc/src/testKit/thirdPartyAudit/build.gradle
+++ b/buildSrc/src/testKit/thirdPartyAudit/build.gradle
@@ -40,7 +40,6 @@ repositories {
 }
 
 dependencies {
-  forbiddenApisCliJar 'de.thetaphi:forbiddenapis:3.2'
   jdkJarHell 'org.opensearch:opensearch-core:current'
   compileOnly "org.${project.properties.compileOnlyGroup}:${project.properties.compileOnlyVersion}"
   implementation "org.${project.properties.compileGroup}:${project.properties.compileVersion}"
diff --git a/buildSrc/src/testKit/thirdPartyAudit/sample_jars/build.gradle b/buildSrc/src/testKit/thirdPartyAudit/sample_jars/build.gradle
index c8c89fb5e4273..cb8050d1718c4 100644
--- a/buildSrc/src/testKit/thirdPartyAudit/sample_jars/build.gradle
+++ b/buildSrc/src/testKit/thirdPartyAudit/sample_jars/build.gradle
@@ -16,7 +16,7 @@ repositories {
   mavenCentral()
 }
 dependencies {
-  implementation 'org.apache.logging.log4j:log4j-core:2.17.2'
+  implementation "org.apache.logging.log4j:log4j-core:2.20.0"
 }
 
 ["0.0.1", "0.0.2"].forEach { v ->
@@ -41,7 +41,7 @@ dependencies {
 ["0.0.1"].forEach { v ->
   ["opensearch", "other"].forEach { p ->
     tasks.register("broken-log4j-${p}-${v}", Jar) {
-      destinationDir = file("${buildDir}/testrepo/org/${p}/gradle/broken-log4j/${v}/")
+      destinationDirectory = file("${buildDir}/testrepo/org/${p}/gradle/broken-log4j/${v}/")
       archiveFileName = "broken-log4j-${v}.jar"
       from sourceSets.main.output
       include "**/TestingLog4j.class"
@@ -51,7 +51,7 @@ dependencies {
 }
 
 tasks.register("jarhellJdk", Jar) {
-  destinationDir = file("${buildDir}/testrepo/org/other/gradle/jarhellJdk/0.0.1/")
+  destinationDirectory = file("${buildDir}/testrepo/org/other/gradle/jarhellJdk/0.0.1/")
   archiveFileName = "jarhellJdk-0.0.1.jar"
   from sourceSets.main.output
   include "**/String.class"
diff --git a/buildSrc/src/testKit/thirdPartyAudit/settings.gradle b/buildSrc/src/testKit/thirdPartyAudit/settings.gradle
index 582faadddaef1..603d8b7da6e5d 100644
--- a/buildSrc/src/testKit/thirdPartyAudit/settings.gradle
+++ b/buildSrc/src/testKit/thirdPartyAudit/settings.gradle
@@ -9,4 +9,4 @@
  * GitHub history for details.
  */
 
-include 'sample_jars'
\ No newline at end of file
+include 'sample_jars'
diff --git a/buildSrc/version.properties b/buildSrc/version.properties
index b5e14cd24bd93..c5db4da86165a 100644
--- a/buildSrc/version.properties
+++ b/buildSrc/version.properties
@@ -1,43 +1,67 @@
-opensearch        = 2.0.0
-lucene            = 9.1.0-snapshot-ea989fe8f30
+opensearch        = 2.11.0
+lucene            = 9.7.0
 
 bundled_jdk_vendor = adoptium
-bundled_jdk = 17.0.2+8
-
-
+bundled_jdk = 17.0.8+7
 
 # optional dependencies
 spatial4j         = 0.7
 jts               = 1.15.0
-jackson           = 2.13.2
-snakeyaml         = 1.26
+jackson           = 2.15.2
+jackson_databind  = 2.15.2
+snakeyaml         = 2.1
 icu4j             = 70.1
 supercsv          = 2.4.0
-log4j             = 2.17.1
-slf4j             = 1.6.2
+log4j             = 2.20.0
+slf4j             = 1.7.36
+asm               = 9.6
+jettison          = 1.5.4
+woodstox          = 6.4.0
+kotlin            = 1.7.10
+antlr4            = 4.11.1
+guava             = 32.1.1-jre
+protobuf          = 3.22.3
+jakarta_annotation = 1.3.5
 
 # when updating the JNA version, also update the version in buildSrc/build.gradle
-jna               = 5.5.0
+jna               = 5.13.0
 
-netty             = 4.1.73.Final
-joda              = 2.10.12
+netty             = 4.1.99.Final
+joda              = 2.12.2
+
+# client dependencies
+httpclient        = 4.5.14
+httpcore          = 4.4.16
+httpasyncclient   = 4.1.5
+commonslogging    = 1.2
+commonscodec      = 1.15
+commonslang       = 3.13.0
+commonscompress   = 1.24.0
+# plugin dependencies
+aws               = 2.20.55
+reactivestreams   = 1.0.4
 
 # when updating this version, you need to ensure compatibility with:
 #  - plugins/ingest-attachment (transitive dependency, check the upstream POM)
 #  - distribution/tools/plugin-cli
-bouncycastle=1.70
+bouncycastle=1.76
 # test dependencies
 randomizedrunner  = 2.7.1
 junit             = 4.13.2
-httpclient        = 4.5.13
-httpcore          = 4.4.12
-httpasyncclient   = 4.1.4
-commonslogging    = 1.1.3
-commonscodec      = 1.13
 hamcrest          = 2.1
-mockito           = 4.3.1
+mockito           = 5.5.0
 objenesis         = 3.2
-bytebuddy         = 1.12.7
+bytebuddy         = 1.14.7
 
 # benchmark dependencies
-jmh               = 1.19
+jmh               = 1.35
+
+# compression
+zstd              = 1.5.5-5
+
+jzlib             = 1.1.3
+
+resteasy          = 6.2.4.Final
+
+# opentelemetry dependencies
+opentelemetry         = 1.30.1
diff --git a/client/benchmark/README.md b/client/benchmark/README.md
index ee99a1384d27e..2732586b9e575 100644
--- a/client/benchmark/README.md
+++ b/client/benchmark/README.md
@@ -29,7 +29,7 @@ Example invocation:
 wget http://benchmarks.elasticsearch.org.s3.amazonaws.com/corpora/geonames/documents-2.json.bz2
 bzip2 -d documents-2.json.bz2
 mv documents-2.json client/benchmark/build
-gradlew -p client/benchmark run --args ' rest bulk localhost build/documents-2.json geonames type 8647880 5000'
+gradlew -p client/benchmark run --args ' rest bulk localhost build/documents-2.json geonames 8647880 5000'
 ```
 
 The parameters are all in the `'`s and are in order:
@@ -39,7 +39,6 @@ The parameters are all in the `'`s and are in order:
 * Benchmark target host IP (the host where OpenSearch is running)
 * full path to the file that should be bulk indexed
 * name of the index
-* name of the (sole) type in the index
 * number of documents in the file
 * bulk size
 
diff --git a/client/benchmark/build.gradle b/client/benchmark/build.gradle
index 4aa4d7171e366..6fd5262f0ab4f 100644
--- a/client/benchmark/build.gradle
+++ b/client/benchmark/build.gradle
@@ -31,13 +31,17 @@
 apply plugin: 'opensearch.build'
 apply plugin: 'application'
 
-group = 'org.opensearch.client'
+base {
+  group = 'org.opensearch.client'
+  archivesBaseName = 'client-benchmarks'
+}
 
 // Not published so no need to assemble
 assemble.enabled = true
 
-archivesBaseName = 'client-benchmarks'
-mainClassName = 'org.opensearch.client.benchmark.BenchmarkMain'
+application {
+  mainClass = 'org.opensearch.client.benchmark.BenchmarkMain'
+}
 
 // never try to invoke tests on the benchmark project - there aren't any
 test.enabled = false
diff --git a/client/benchmark/src/main/java/org/opensearch/client/benchmark/AbstractBenchmark.java b/client/benchmark/src/main/java/org/opensearch/client/benchmark/AbstractBenchmark.java
index de9d075cb9a16..ab0a0d6b8a19c 100644
--- a/client/benchmark/src/main/java/org/opensearch/client/benchmark/AbstractBenchmark.java
+++ b/client/benchmark/src/main/java/org/opensearch/client/benchmark/AbstractBenchmark.java
@@ -49,7 +49,7 @@ public abstract class AbstractBenchmark<T extends Closeable> {
 
     protected abstract T client(String benchmarkTargetHost) throws Exception;
 
-    protected abstract BulkRequestExecutor bulkRequestExecutor(T client, String indexName, String typeName);
+    protected abstract BulkRequestExecutor bulkRequestExecutor(T client, String indexName);
 
     protected abstract SearchRequestExecutor searchRequestExecutor(T client, String indexName);
 
@@ -76,16 +76,15 @@ public final void run(String[] args) throws Exception {
 
     @SuppressForbidden(reason = "system out is ok for a command line tool")
     private void runBulkIndexBenchmark(String[] args) throws Exception {
-        if (args.length != 7) {
-            System.err.println("usage: 'bulk' benchmarkTargetHostIp indexFilePath indexName typeName numberOfDocuments bulkSize");
+        if (args.length != 6) {
+            System.err.println("usage: 'bulk' benchmarkTargetHostIp indexFilePath indexName numberOfDocuments bulkSize");
             System.exit(1);
         }
         String benchmarkTargetHost = args[1];
         String indexFilePath = args[2];
         String indexName = args[3];
-        String typeName = args[4];
-        int totalDocs = Integer.valueOf(args[5]);
-        int bulkSize = Integer.valueOf(args[6]);
+        int totalDocs = Integer.valueOf(args[4]);
+        int bulkSize = Integer.valueOf(args[5]);
 
         int totalIterationCount = (int) Math.floor(totalDocs / bulkSize);
         // consider 40% of all iterations as warmup iterations
@@ -97,7 +96,7 @@ private void runBulkIndexBenchmark(String[] args) throws Exception {
         BenchmarkRunner benchmark = new BenchmarkRunner(
             warmupIterations,
             iterations,
-            new BulkBenchmarkTask(bulkRequestExecutor(client, indexName, typeName), indexFilePath, warmupIterations, iterations, bulkSize)
+            new BulkBenchmarkTask(bulkRequestExecutor(client, indexName), indexFilePath, warmupIterations, iterations, bulkSize)
         );
 
         try {
diff --git a/client/benchmark/src/main/java/org/opensearch/client/benchmark/ops/bulk/BulkBenchmarkTask.java b/client/benchmark/src/main/java/org/opensearch/client/benchmark/ops/bulk/BulkBenchmarkTask.java
index 459cba1ce5f23..5d2b9cb764a6f 100644
--- a/client/benchmark/src/main/java/org/opensearch/client/benchmark/ops/bulk/BulkBenchmarkTask.java
+++ b/client/benchmark/src/main/java/org/opensearch/client/benchmark/ops/bulk/BulkBenchmarkTask.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.client.benchmark.ops.bulk;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
 import org.opensearch.client.benchmark.BenchmarkTask;
 import org.opensearch.client.benchmark.metrics.Sample;
diff --git a/client/benchmark/src/main/java/org/opensearch/client/benchmark/rest/RestClientBenchmark.java b/client/benchmark/src/main/java/org/opensearch/client/benchmark/rest/RestClientBenchmark.java
index 073fd5eab5c46..d2d7163b8dee2 100644
--- a/client/benchmark/src/main/java/org/opensearch/client/benchmark/rest/RestClientBenchmark.java
+++ b/client/benchmark/src/main/java/org/opensearch/client/benchmark/rest/RestClientBenchmark.java
@@ -65,8 +65,8 @@ protected RestClient client(String benchmarkTargetHost) {
     }
 
     @Override
-    protected BulkRequestExecutor bulkRequestExecutor(RestClient client, String indexName, String typeName) {
-        return new RestBulkRequestExecutor(client, indexName, typeName);
+    protected BulkRequestExecutor bulkRequestExecutor(RestClient client, String indexName) {
+        return new RestBulkRequestExecutor(client, indexName);
     }
 
     @Override
@@ -78,9 +78,9 @@ private static final class RestBulkRequestExecutor implements BulkRequestExecuto
         private final RestClient client;
         private final String actionMetadata;
 
-        RestBulkRequestExecutor(RestClient client, String index, String type) {
+        RestBulkRequestExecutor(RestClient client, String index) {
             this.client = client;
-            this.actionMetadata = String.format(Locale.ROOT, "{ \"index\" : { \"_index\" : \"%s\", \"_type\" : \"%s\" } }%n", index, type);
+            this.actionMetadata = String.format(Locale.ROOT, "{ \"index\" : { \"_index\" : \"%s\" } }%n", index);
         }
 
         @Override
@@ -91,7 +91,7 @@ public boolean bulkIndex(List<String> bulkData) {
                 bulkRequestBody.append(bulkItem);
                 bulkRequestBody.append("\n");
             }
-            Request request = new Request("POST", "/geonames/type/_noop_bulk");
+            Request request = new Request("POST", "/geonames/_noop_bulk");
             request.setJsonEntity(bulkRequestBody.toString());
             try {
                 Response response = client.performRequest(request);
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/NoopPlugin.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/NoopPlugin.java
index e9d0fff2a9dc9..56bf91d1b2360 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/NoopPlugin.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/NoopPlugin.java
@@ -31,17 +31,17 @@
 
 package org.opensearch.plugin.noop;
 
-import org.opensearch.plugin.noop.action.bulk.NoopBulkAction;
-import org.opensearch.plugin.noop.action.bulk.RestNoopBulkAction;
-import org.opensearch.plugin.noop.action.bulk.TransportNoopBulkAction;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.plugin.noop.action.bulk.NoopBulkAction;
+import org.opensearch.plugin.noop.action.bulk.RestNoopBulkAction;
+import org.opensearch.plugin.noop.action.bulk.TransportNoopBulkAction;
 import org.opensearch.plugin.noop.action.search.NoopSearchAction;
 import org.opensearch.plugin.noop.action.search.RestNoopSearchAction;
 import org.opensearch.plugin.noop.action.search.TransportNoopSearchAction;
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/RestNoopBulkAction.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/RestNoopBulkAction.java
index 1e94939bed7b5..8bd35a0bfed6a 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/RestNoopBulkAction.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/RestNoopBulkAction.java
@@ -40,8 +40,8 @@
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
@@ -54,9 +54,9 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
-import static org.opensearch.rest.RestStatus.OK;
 
 public class RestNoopBulkAction extends BaseRestHandler {
 
@@ -99,7 +99,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             defaultPipeline,
             defaultRequireAlias,
             true,
-            request.getXContentType()
+            request.getMediaType()
         );
 
         // short circuit the call to the transport layer
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/TransportNoopBulkAction.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/TransportNoopBulkAction.java
index 22dd96a0bdfc5..77d4d3d095b29 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/TransportNoopBulkAction.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/bulk/TransportNoopBulkAction.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.plugin.noop.action.bulk;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
@@ -41,7 +40,8 @@
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/search/TransportNoopSearchAction.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/search/TransportNoopSearchAction.java
index 77668a030ee7f..99efd31dfcaa5 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/search/TransportNoopSearchAction.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/opensearch/plugin/noop/action/search/TransportNoopSearchAction.java
@@ -32,14 +32,14 @@
 package org.opensearch.plugin.noop.action.search;
 
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.InternalAggregations;
diff --git a/client/rest-high-level/build.gradle b/client/rest-high-level/build.gradle
index 07147ce81b72e..cc8262ff6d9ad 100644
--- a/client/rest-high-level/build.gradle
+++ b/client/rest-high-level/build.gradle
@@ -37,8 +37,10 @@ apply plugin: 'opensearch.rest-test'
 apply plugin: 'opensearch.publish'
 apply plugin: 'opensearch.rest-resources'
 
-group = 'org.opensearch.client'
-archivesBaseName = 'opensearch-rest-high-level-client'
+base {
+  group = 'org.opensearch.client'
+  archivesBaseName = 'opensearch-rest-high-level-client'
+}
 
 restResources {
   //we need to copy the yaml spec so we can check naming (see RestHighlevelClientTests#testApiNamingConventions)
@@ -103,4 +105,5 @@ testClusters.all {
   extraConfigFile nodeCert.name, nodeCert
   extraConfigFile nodeTrustStore.name, nodeTrustStore
   extraConfigFile pkiTrustCert.name, pkiTrustCert
+
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/ClusterClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/ClusterClient.java
index 10cfec9497862..5bd5a5d0e308e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/ClusterClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/ClusterClient.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.settings.ClusterGetSettingsRequest;
@@ -47,7 +46,8 @@
 import org.opensearch.client.indices.GetComponentTemplatesRequest;
 import org.opensearch.client.indices.GetComponentTemplatesResponse;
 import org.opensearch.client.indices.PutComponentTemplateRequest;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/ClusterRequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/ClusterRequestConverters.java
index 1cf52ac4169ba..8014eb946b144 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/ClusterRequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/ClusterRequestConverters.java
@@ -45,7 +45,7 @@
 import org.opensearch.client.indices.DeleteComponentTemplateRequest;
 import org.opensearch.client.indices.GetComponentTemplatesRequest;
 import org.opensearch.client.indices.PutComponentTemplateRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 
@@ -58,7 +58,7 @@ static Request clusterPutSettings(ClusterUpdateSettingsRequest clusterUpdateSett
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(clusterUpdateSettingsRequest.timeout());
-        parameters.withMasterTimeout(clusterUpdateSettingsRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(clusterUpdateSettingsRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(clusterUpdateSettingsRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
         return request;
@@ -69,7 +69,7 @@ static Request clusterGetSettings(ClusterGetSettingsRequest clusterGetSettingsRe
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withLocal(clusterGetSettingsRequest.local());
         parameters.withIncludeDefaults(clusterGetSettingsRequest.includeDefaults());
-        parameters.withMasterTimeout(clusterGetSettingsRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(clusterGetSettingsRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
@@ -88,7 +88,7 @@ static Request clusterHealth(ClusterHealthRequest healthRequest) {
             .withWaitForNodes(healthRequest.waitForNodes())
             .withWaitForEvents(healthRequest.waitForEvents())
             .withTimeout(healthRequest.timeout())
-            .withMasterTimeout(healthRequest.masterNodeTimeout())
+            .withMasterTimeout(healthRequest.clusterManagerNodeTimeout())
             .withLocal(healthRequest.local())
             .withLevel(healthRequest.level());
         request.addParameters(params.asMap());
@@ -105,7 +105,7 @@ static Request putComponentTemplate(PutComponentTemplateRequest putComponentTemp
             .build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(putComponentTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(putComponentTemplateRequest.clusterManagerNodeTimeout());
         if (putComponentTemplateRequest.create()) {
             params.putParam("create", Boolean.TRUE.toString());
         }
@@ -146,7 +146,7 @@ static Request deleteComponentTemplate(DeleteComponentTemplateRequest deleteComp
         String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_component_template").addPathPart(name).build();
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(deleteComponentTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(deleteComponentTemplateRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/GetAliasesResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/GetAliasesResponse.java
index 81fd040ae6dee..c79be0a668896 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/GetAliasesResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/GetAliasesResponse.java
@@ -35,11 +35,11 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -48,7 +48,7 @@
 import java.util.Map;
 import java.util.Set;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Response obtained from the get aliases API.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/IndicesClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/IndicesClient.java
index 9b4586ec6bf89..281f020533d51 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/IndicesClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/IndicesClient.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.cache.clear.ClearIndicesCacheRequest;
@@ -88,7 +87,8 @@
 import org.opensearch.client.indices.SimulateIndexTemplateResponse;
 import org.opensearch.client.indices.rollover.RolloverRequest;
 import org.opensearch.client.indices.rollover.RolloverResponse;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/IndicesRequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/IndicesRequestConverters.java
index c50ea58982e4e..75a82a752281a 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/IndicesRequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/IndicesRequestConverters.java
@@ -52,28 +52,28 @@
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryRequest;
 import org.opensearch.client.indices.AnalyzeRequest;
 import org.opensearch.client.indices.CloseIndexRequest;
+import org.opensearch.client.indices.ComposableIndexTemplateExistRequest;
 import org.opensearch.client.indices.CreateDataStreamRequest;
 import org.opensearch.client.indices.CreateIndexRequest;
 import org.opensearch.client.indices.DataStreamsStatsRequest;
-import org.opensearch.client.indices.GetDataStreamRequest;
 import org.opensearch.client.indices.DeleteAliasRequest;
 import org.opensearch.client.indices.DeleteComposableIndexTemplateRequest;
 import org.opensearch.client.indices.DeleteDataStreamRequest;
+import org.opensearch.client.indices.GetComposableIndexTemplateRequest;
+import org.opensearch.client.indices.GetDataStreamRequest;
 import org.opensearch.client.indices.GetFieldMappingsRequest;
 import org.opensearch.client.indices.GetIndexRequest;
-import org.opensearch.client.indices.GetComposableIndexTemplateRequest;
 import org.opensearch.client.indices.GetIndexTemplatesRequest;
 import org.opensearch.client.indices.GetMappingsRequest;
-import org.opensearch.client.indices.ComposableIndexTemplateExistRequest;
 import org.opensearch.client.indices.IndexTemplatesExistRequest;
-import org.opensearch.client.indices.PutIndexTemplateRequest;
 import org.opensearch.client.indices.PutComposableIndexTemplateRequest;
+import org.opensearch.client.indices.PutIndexTemplateRequest;
 import org.opensearch.client.indices.PutMappingRequest;
 import org.opensearch.client.indices.ResizeRequest;
 import org.opensearch.client.indices.SimulateIndexTemplateRequest;
 import org.opensearch.client.indices.rollover.RolloverRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -119,7 +119,7 @@ static Request deleteIndex(DeleteIndexRequest deleteIndexRequest) {
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(deleteIndexRequest.timeout());
-        parameters.withMasterTimeout(deleteIndexRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(deleteIndexRequest.clusterManagerNodeTimeout());
         parameters.withIndicesOptions(deleteIndexRequest.indicesOptions());
         request.addParameters(parameters.asMap());
         return request;
@@ -131,7 +131,7 @@ static Request openIndex(OpenIndexRequest openIndexRequest) {
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(openIndexRequest.timeout());
-        parameters.withMasterTimeout(openIndexRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(openIndexRequest.clusterManagerNodeTimeout());
         parameters.withWaitForActiveShards(openIndexRequest.waitForActiveShards());
         parameters.withIndicesOptions(openIndexRequest.indicesOptions());
         request.addParameters(parameters.asMap());
@@ -144,7 +144,7 @@ static Request closeIndex(CloseIndexRequest closeIndexRequest) {
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(closeIndexRequest.timeout());
-        parameters.withMasterTimeout(closeIndexRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(closeIndexRequest.clusterManagerNodeTimeout());
         parameters.withIndicesOptions(closeIndexRequest.indicesOptions());
         request.addParameters(parameters.asMap());
         return request;
@@ -156,7 +156,7 @@ static Request createIndex(CreateIndexRequest createIndexRequest) throws IOExcep
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(createIndexRequest.timeout());
-        parameters.withMasterTimeout(createIndexRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(createIndexRequest.clusterManagerNodeTimeout());
         parameters.withWaitForActiveShards(createIndexRequest.waitForActiveShards());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(createIndexRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -168,7 +168,7 @@ static Request updateAliases(IndicesAliasesRequest indicesAliasesRequest) throws
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(indicesAliasesRequest.timeout());
-        parameters.withMasterTimeout(indicesAliasesRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(indicesAliasesRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(indicesAliasesRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
         return request;
@@ -179,7 +179,7 @@ static Request putMapping(PutMappingRequest putMappingRequest) throws IOExceptio
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(putMappingRequest.timeout());
-        parameters.withMasterTimeout(putMappingRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(putMappingRequest.clusterManagerNodeTimeout());
         parameters.withIndicesOptions(putMappingRequest.indicesOptions());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(putMappingRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -192,7 +192,7 @@ static Request getMappings(GetMappingsRequest getMappingsRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, RequestConverters.endpoint(indices, "_mapping"));
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(getMappingsRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(getMappingsRequest.clusterManagerNodeTimeout());
         parameters.withIndicesOptions(getMappingsRequest.indicesOptions());
         parameters.withLocal(getMappingsRequest.local());
         request.addParameters(parameters.asMap());
@@ -261,6 +261,7 @@ static Request clearCache(ClearIndicesCacheRequest clearIndicesCacheRequest) {
         parameters.withIndicesOptions(clearIndicesCacheRequest.indicesOptions());
         parameters.putParam("query", Boolean.toString(clearIndicesCacheRequest.queryCache()));
         parameters.putParam("fielddata", Boolean.toString(clearIndicesCacheRequest.fieldDataCache()));
+        parameters.putParam("file", Boolean.toString(clearIndicesCacheRequest.fileCache()));
         parameters.putParam("request", Boolean.toString(clearIndicesCacheRequest.requestCache()));
         parameters.putParam("fields", String.join(",", clearIndicesCacheRequest.fields()));
         request.addParameters(parameters.asMap());
@@ -332,7 +333,7 @@ private static Request resize(ResizeRequest resizeRequest, ResizeType type) thro
 
         RequestConverters.Params params = new RequestConverters.Params();
         params.withTimeout(resizeRequest.timeout());
-        params.withMasterTimeout(resizeRequest.masterNodeTimeout());
+        params.withMasterTimeout(resizeRequest.clusterManagerNodeTimeout());
         params.withWaitForActiveShards(resizeRequest.getWaitForActiveShards());
         request.addParameters(params.asMap());
         request.setEntity(RequestConverters.createEntity(resizeRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -349,7 +350,7 @@ private static Request resize(org.opensearch.action.admin.indices.shrink.ResizeR
 
         RequestConverters.Params params = new RequestConverters.Params();
         params.withTimeout(resizeRequest.timeout());
-        params.withMasterTimeout(resizeRequest.masterNodeTimeout());
+        params.withMasterTimeout(resizeRequest.clusterManagerNodeTimeout());
         params.withWaitForActiveShards(resizeRequest.getTargetIndexRequest().waitForActiveShards());
         request.addParameters(params.asMap());
         request.setEntity(RequestConverters.createEntity(resizeRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -365,7 +366,7 @@ static Request rollover(RolloverRequest rolloverRequest) throws IOException {
 
         RequestConverters.Params params = new RequestConverters.Params();
         params.withTimeout(rolloverRequest.timeout());
-        params.withMasterTimeout(rolloverRequest.masterNodeTimeout());
+        params.withMasterTimeout(rolloverRequest.clusterManagerNodeTimeout());
         params.withWaitForActiveShards(rolloverRequest.getCreateIndexRequest().waitForActiveShards());
         if (rolloverRequest.isDryRun()) {
             params.putParam("dry_run", Boolean.TRUE.toString());
@@ -386,7 +387,7 @@ static Request getSettings(GetSettingsRequest getSettingsRequest) {
         params.withIndicesOptions(getSettingsRequest.indicesOptions());
         params.withLocal(getSettingsRequest.local());
         params.withIncludeDefaults(getSettingsRequest.includeDefaults());
-        params.withMasterTimeout(getSettingsRequest.masterNodeTimeout());
+        params.withMasterTimeout(getSettingsRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
@@ -402,7 +403,7 @@ static Request getIndex(GetIndexRequest getIndexRequest) {
         params.withLocal(getIndexRequest.local());
         params.withIncludeDefaults(getIndexRequest.includeDefaults());
         params.withHuman(getIndexRequest.humanReadable());
-        params.withMasterTimeout(getIndexRequest.masterNodeTimeout());
+        params.withMasterTimeout(getIndexRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
@@ -429,7 +430,7 @@ static Request indexPutSettings(UpdateSettingsRequest updateSettingsRequest) thr
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(updateSettingsRequest.timeout());
-        parameters.withMasterTimeout(updateSettingsRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(updateSettingsRequest.clusterManagerNodeTimeout());
         parameters.withIndicesOptions(updateSettingsRequest.indicesOptions());
         parameters.withPreserveExisting(updateSettingsRequest.isPreserveExisting());
         request.addParameters(parameters.asMap());
@@ -443,7 +444,7 @@ static Request putTemplate(PutIndexTemplateRequest putIndexTemplateRequest) thro
             .build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(putIndexTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(putIndexTemplateRequest.clusterManagerNodeTimeout());
         if (putIndexTemplateRequest.create()) {
             params.putParam("create", Boolean.TRUE.toString());
         }
@@ -461,7 +462,7 @@ static Request putIndexTemplate(PutComposableIndexTemplateRequest putIndexTempla
             .build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(putIndexTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(putIndexTemplateRequest.clusterManagerNodeTimeout());
         if (putIndexTemplateRequest.create()) {
             params.putParam("create", Boolean.TRUE.toString());
         }
@@ -479,7 +480,7 @@ static Request simulateIndexTemplate(SimulateIndexTemplateRequest simulateIndexT
             .build();
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(simulateIndexTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(simulateIndexTemplateRequest.clusterManagerNodeTimeout());
         PutComposableIndexTemplateRequest putComposableIndexTemplateRequest = simulateIndexTemplateRequest.indexTemplateV2Request();
         if (putComposableIndexTemplateRequest != null) {
             if (putComposableIndexTemplateRequest.create()) {
@@ -587,7 +588,7 @@ static Request deleteTemplate(DeleteIndexTemplateRequest deleteIndexTemplateRequ
         String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_template").addPathPart(name).build();
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(deleteIndexTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(deleteIndexTemplateRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
@@ -597,7 +598,7 @@ static Request deleteIndexTemplate(DeleteComposableIndexTemplateRequest deleteIn
         String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_index_template").addPathPart(name).build();
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(deleteIndexTemplateRequest.masterNodeTimeout());
+        params.withMasterTimeout(deleteIndexTemplateRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
@@ -610,7 +611,7 @@ static Request deleteAlias(DeleteAliasRequest deleteAliasRequest) {
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(deleteAliasRequest.timeout());
-        parameters.withMasterTimeout(deleteAliasRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(deleteAliasRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/IngestClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/IngestClient.java
index cd304019e771c..29e5c5369f184 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/IngestClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/IngestClient.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ingest.DeletePipelineRequest;
 import org.opensearch.action.ingest.GetPipelineRequest;
 import org.opensearch.action.ingest.GetPipelineResponse;
@@ -40,6 +39,7 @@
 import org.opensearch.action.ingest.SimulatePipelineRequest;
 import org.opensearch.action.ingest.SimulatePipelineResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/IngestRequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/IngestRequestConverters.java
index e2ede61f38ee9..a80a2b57fe2f7 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/IngestRequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/IngestRequestConverters.java
@@ -54,7 +54,7 @@ static Request getPipeline(GetPipelineRequest getPipelineRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(getPipelineRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(getPipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
@@ -67,7 +67,7 @@ static Request putPipeline(PutPipelineRequest putPipelineRequest) throws IOExcep
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(putPipelineRequest.timeout());
-        parameters.withMasterTimeout(putPipelineRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(putPipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(putPipelineRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
         return request;
@@ -81,7 +81,7 @@ static Request deletePipeline(DeletePipelineRequest deletePipelineRequest) {
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(deletePipelineRequest.timeout());
-        parameters.withMasterTimeout(deletePipelineRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(deletePipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponse.java
index 0f05f3e360232..589ab92a6de39 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponse.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.client;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
 
 /**
  * Base class for responses that are node responses. These responses always contain the cluster
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponseHeader.java b/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponseHeader.java
index 7b09467798606..3b2e7ce7edd00 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponseHeader.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/NodesResponseHeader.java
@@ -34,11 +34,11 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.RestActions;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/RequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/RequestConverters.java
index 3e43963db519f..0dd74e663ba71 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/RequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/RequestConverters.java
@@ -54,6 +54,8 @@
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.ClearScrollRequest;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.DeletePitRequest;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchScrollRequest;
@@ -70,20 +72,21 @@
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.rankeval.RankEvalRequest;
@@ -92,6 +95,7 @@
 import org.opensearch.index.reindex.ReindexRequest;
 import org.opensearch.index.reindex.UpdateByQueryRequest;
 import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.rest.action.search.RestCreatePitAction;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.script.mustache.MultiSearchTemplateRequest;
 import org.opensearch.script.mustache.SearchTemplateRequest;
@@ -109,8 +113,13 @@
 import java.util.Map;
 import java.util.StringJoiner;
 
+/**
+ * Converts OpenSearch writeable requests to an HTTP Request
+ *
+ * @opensearch.api
+ */
 final class RequestConverters {
-    static final XContentType REQUEST_BODY_CONTENT_TYPE = XContentType.JSON;
+    static final MediaType REQUEST_BODY_CONTENT_TYPE = MediaTypeRegistry.JSON;
 
     private RequestConverters() {
         // Contains only status utility methods
@@ -148,7 +157,7 @@ static Request bulk(BulkRequest bulkRequest) throws IOException {
         // Bulk API only supports newline delimited JSON or Smile. Before executing
         // the bulk, we need to check that all requests have the same content-type
         // and this content-type is supported by the Bulk API.
-        XContentType bulkContentType = null;
+        MediaType bulkContentType = null;
         for (int i = 0; i < bulkRequest.numberOfActions(); i++) {
             DocWriteRequest<?> action = bulkRequest.requests().get(i);
 
@@ -168,7 +177,7 @@ static Request bulk(BulkRequest bulkRequest) throws IOException {
         }
 
         if (bulkContentType == null) {
-            bulkContentType = XContentType.JSON;
+            bulkContentType = MediaTypeRegistry.JSON;
         }
 
         final byte separator = bulkContentType.xContent().streamSeparator();
@@ -236,7 +245,7 @@ static Request bulk(BulkRequest bulkRequest) throws IOException {
             if (opType == DocWriteRequest.OpType.INDEX || opType == DocWriteRequest.OpType.CREATE) {
                 IndexRequest indexRequest = (IndexRequest) action;
                 BytesReference indexSource = indexRequest.source();
-                XContentType indexXContentType = indexRequest.getContentType();
+                MediaType mediaType = indexRequest.getContentType();
 
                 try (
                     XContentParser parser = XContentHelper.createParser(
@@ -248,7 +257,7 @@ static Request bulk(BulkRequest bulkRequest) throws IOException {
                         NamedXContentRegistry.EMPTY,
                         DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                         indexSource,
-                        indexXContentType
+                        mediaType
                     )
                 ) {
                     try (XContentBuilder builder = XContentBuilder.builder(bulkContentType.xContent())) {
@@ -257,7 +266,12 @@ static Request bulk(BulkRequest bulkRequest) throws IOException {
                     }
                 }
             } else if (opType == DocWriteRequest.OpType.UPDATE) {
-                source = XContentHelper.toXContent((UpdateRequest) action, bulkContentType, false).toBytesRef();
+                source = org.opensearch.core.xcontent.XContentHelper.toXContent(
+                    (UpdateRequest) action,
+                    bulkContentType,
+                    ToXContent.EMPTY_PARAMS,
+                    false
+                ).toBytesRef();
             }
 
             if (source != null) {
@@ -383,30 +397,30 @@ static Request update(UpdateRequest updateRequest) throws IOException {
         // set for the partial document and the upsert document. This client
         // only accepts update requests that have the same content types set
         // for both doc and upsert.
-        XContentType xContentType = null;
+        MediaType mediaType = null;
         if (updateRequest.doc() != null) {
-            xContentType = updateRequest.doc().getContentType();
+            mediaType = updateRequest.doc().getContentType();
         }
         if (updateRequest.upsertRequest() != null) {
-            XContentType upsertContentType = updateRequest.upsertRequest().getContentType();
-            if ((xContentType != null) && (xContentType != upsertContentType)) {
+            MediaType upsertContentType = updateRequest.upsertRequest().getContentType();
+            if ((mediaType != null) && (mediaType != upsertContentType)) {
                 throw new IllegalStateException(
                     "Update request cannot have different content types for doc ["
-                        + xContentType
+                        + mediaType
                         + "]"
                         + " and upsert ["
                         + upsertContentType
                         + "] documents"
                 );
             } else {
-                xContentType = upsertContentType;
+                mediaType = upsertContentType;
             }
         }
-        if (xContentType == null) {
-            xContentType = Requests.INDEX_CONTENT_TYPE;
+        if (mediaType == null) {
+            mediaType = Requests.INDEX_CONTENT_TYPE;
         }
         request.addParameters(parameters.asMap());
-        request.setEntity(createEntity(updateRequest, xContentType));
+        request.setEntity(createEntity(updateRequest, mediaType));
         return request;
     }
 
@@ -433,9 +447,19 @@ static void addSearchRequestParams(Params params, SearchRequest searchRequest) {
         params.putParam(RestSearchAction.TYPED_KEYS_PARAM, "true");
         params.withRouting(searchRequest.routing());
         params.withPreference(searchRequest.preference());
-        params.withIndicesOptions(searchRequest.indicesOptions());
+        if (searchRequest.pointInTimeBuilder() == null) {
+            params.withIndicesOptions(searchRequest.indicesOptions());
+        }
         params.withSearchType(searchRequest.searchType().name().toLowerCase(Locale.ROOT));
-        params.putParam("ccs_minimize_roundtrips", Boolean.toString(searchRequest.isCcsMinimizeRoundtrips()));
+        /**
+         * Merging search responses as part of CCS flow to reduce roundtrips is not supported for point in time -
+         * refer to org.opensearch.action.search.SearchResponseMerger
+         */
+        if (searchRequest.pointInTimeBuilder() != null) {
+            params.putParam("ccs_minimize_roundtrips", "false");
+        } else {
+            params.putParam("ccs_minimize_roundtrips", Boolean.toString(searchRequest.isCcsMinimizeRoundtrips()));
+        }
         if (searchRequest.getPreFilterShardSize() != null) {
             params.putParam("pre_filter_shard_size", Integer.toString(searchRequest.getPreFilterShardSize()));
         }
@@ -464,6 +488,31 @@ static Request clearScroll(ClearScrollRequest clearScrollRequest) throws IOExcep
         return request;
     }
 
+    static Request createPit(CreatePitRequest createPitRequest) throws IOException {
+        Params params = new Params();
+        params.putParam(RestCreatePitAction.ALLOW_PARTIAL_PIT_CREATION, Boolean.toString(createPitRequest.shouldAllowPartialPitCreation()));
+        params.putParam(RestCreatePitAction.KEEP_ALIVE, createPitRequest.getKeepAlive());
+        params.withIndicesOptions(createPitRequest.indicesOptions());
+        Request request = new Request(HttpPost.METHOD_NAME, endpoint(createPitRequest.indices(), "_search/point_in_time"));
+        request.addParameters(params.asMap());
+        request.setEntity(createEntity(createPitRequest, REQUEST_BODY_CONTENT_TYPE));
+        return request;
+    }
+
+    static Request deletePit(DeletePitRequest deletePitRequest) throws IOException {
+        Request request = new Request(HttpDelete.METHOD_NAME, "/_search/point_in_time");
+        request.setEntity(createEntity(deletePitRequest, REQUEST_BODY_CONTENT_TYPE));
+        return request;
+    }
+
+    static Request deleteAllPits() {
+        return new Request(HttpDelete.METHOD_NAME, "/_search/point_in_time/_all");
+    }
+
+    static Request getAllPits() {
+        return new Request(HttpGet.METHOD_NAME, "/_search/point_in_time/_all");
+    }
+
     static Request multiSearch(MultiSearchRequest multiSearchRequest) throws IOException {
         Request request = new Request(HttpPost.METHOD_NAME, "/_msearch");
 
@@ -476,7 +525,7 @@ static Request multiSearch(MultiSearchRequest multiSearchRequest) throws IOExcep
         XContent xContent = REQUEST_BODY_CONTENT_TYPE.xContent();
         byte[] source = MultiSearchRequest.writeMultiLineFormat(multiSearchRequest, xContent);
         request.addParameters(params.asMap());
-        request.setEntity(new NByteArrayEntity(source, createContentType(xContent.type())));
+        request.setEntity(new NByteArrayEntity(source, createContentType(xContent.mediaType())));
         return request;
     }
 
@@ -511,7 +560,7 @@ static Request multiSearchTemplate(MultiSearchTemplateRequest multiSearchTemplat
 
         XContent xContent = REQUEST_BODY_CONTENT_TYPE.xContent();
         byte[] source = MultiSearchTemplateRequest.writeMultiLineFormat(multiSearchTemplateRequest, xContent);
-        request.setEntity(new NByteArrayEntity(source, createContentType(xContent.type())));
+        request.setEntity(new NByteArrayEntity(source, createContentType(xContent.mediaType())));
         return request;
     }
 
@@ -702,7 +751,7 @@ static Request putScript(PutStoredScriptRequest putStoredScriptRequest) throws I
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
         Params params = new Params();
         params.withTimeout(putStoredScriptRequest.timeout());
-        params.withMasterTimeout(putStoredScriptRequest.masterNodeTimeout());
+        params.withMasterTimeout(putStoredScriptRequest.clusterManagerNodeTimeout());
         if (Strings.hasText(putStoredScriptRequest.context())) {
             params.putParam("context", putStoredScriptRequest.context());
         }
@@ -757,7 +806,7 @@ static Request getScript(GetStoredScriptRequest getStoredScriptRequest) {
         String endpoint = new EndpointBuilder().addPathPartAsIs("_scripts").addPathPart(getStoredScriptRequest.id()).build();
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
         Params params = new Params();
-        params.withMasterTimeout(getStoredScriptRequest.masterNodeTimeout());
+        params.withMasterTimeout(getStoredScriptRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
@@ -767,19 +816,19 @@ static Request deleteScript(DeleteStoredScriptRequest deleteStoredScriptRequest)
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
         Params params = new Params();
         params.withTimeout(deleteStoredScriptRequest.timeout());
-        params.withMasterTimeout(deleteStoredScriptRequest.masterNodeTimeout());
+        params.withMasterTimeout(deleteStoredScriptRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         return request;
     }
 
-    static HttpEntity createEntity(ToXContent toXContent, XContentType xContentType) throws IOException {
-        return createEntity(toXContent, xContentType, ToXContent.EMPTY_PARAMS);
+    static HttpEntity createEntity(ToXContent toXContent, MediaType mediaType) throws IOException {
+        return createEntity(toXContent, mediaType, ToXContent.EMPTY_PARAMS);
     }
 
-    static HttpEntity createEntity(ToXContent toXContent, XContentType xContentType, ToXContent.Params toXContentParams)
-        throws IOException {
-        BytesRef source = XContentHelper.toXContent(toXContent, xContentType, toXContentParams, false).toBytesRef();
-        return new NByteArrayEntity(source.bytes, source.offset, source.length, createContentType(xContentType));
+    static HttpEntity createEntity(ToXContent toXContent, MediaType mediaType, ToXContent.Params toXContentParams) throws IOException {
+        BytesRef source = org.opensearch.core.xcontent.XContentHelper.toXContent(toXContent, mediaType, toXContentParams, false)
+            .toBytesRef();
+        return new NByteArrayEntity(source.bytes, source.offset, source.length, createContentType(mediaType));
     }
 
     static String endpoint(String index, String id) {
@@ -825,14 +874,14 @@ static String endpoint(String[] indices, String endpoint, String type) {
     }
 
     /**
-     * Returns a {@link ContentType} from a given {@link XContentType}.
+     * Returns a {@link ContentType} from a given {@link MediaType}.
      *
-     * @param xContentType the {@link XContentType}
+     * @param mediaType the {@link MediaType}
      * @return the {@link ContentType}
      */
-    @SuppressForbidden(reason = "Only allowed place to convert a XContentType to a ContentType")
-    public static ContentType createContentType(final XContentType xContentType) {
-        return ContentType.create(xContentType.mediaTypeWithoutParameters(), (Charset) null);
+    @SuppressForbidden(reason = "Only allowed place to convert a MediaType to a ContentType")
+    public static ContentType createContentType(final MediaType mediaType) {
+        return ContentType.create(mediaType.mediaTypeWithoutParameters(), (Charset) null);
     }
 
     /**
@@ -1128,14 +1177,14 @@ Params withActions(List<String> actions) {
             return this;
         }
 
-        Params withTaskId(org.opensearch.tasks.TaskId taskId) {
+        Params withTaskId(org.opensearch.core.tasks.TaskId taskId) {
             if (taskId != null && taskId.isSet()) {
                 return putParam("task_id", taskId.toString());
             }
             return this;
         }
 
-        Params withParentTaskId(org.opensearch.tasks.TaskId parentTaskId) {
+        Params withParentTaskId(org.opensearch.core.tasks.TaskId parentTaskId) {
             if (parentTaskId != null && parentTaskId.isSet()) {
                 return putParam("parent_task_id", parentTaskId.toString());
             }
@@ -1199,28 +1248,28 @@ Params withWaitForEvents(Priority waitForEvents) {
      *
      * @return the {@link IndexRequest}'s content type
      */
-    static XContentType enforceSameContentType(IndexRequest indexRequest, @Nullable XContentType xContentType) {
-        XContentType requestContentType = indexRequest.getContentType();
-        if (requestContentType != XContentType.JSON && requestContentType != XContentType.SMILE) {
+    static MediaType enforceSameContentType(IndexRequest indexRequest, @Nullable MediaType mediaType) {
+        MediaType requestContentType = indexRequest.getContentType();
+        if (requestContentType != MediaTypeRegistry.JSON && requestContentType != MediaTypeRegistry.fromFormat("smile")) {
             throw new IllegalArgumentException(
                 "Unsupported content-type found for request with content-type ["
                     + requestContentType
                     + "], only JSON and SMILE are supported"
             );
         }
-        if (xContentType == null) {
+        if (mediaType == null) {
             return requestContentType;
         }
-        if (requestContentType != xContentType) {
+        if (requestContentType != mediaType) {
             throw new IllegalArgumentException(
                 "Mismatching content-type found for request with content-type ["
                     + requestContentType
                     + "], previous requests have content-type ["
-                    + xContentType
+                    + mediaType
                     + "]"
             );
         }
-        return xContentType;
+        return mediaType;
     }
 
     /**
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/RestHighLevelClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/RestHighLevelClient.java
index 3eebb361fd9c4..94303097c772d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/RestHighLevelClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/RestHighLevelClient.java
@@ -35,7 +35,6 @@
 import org.apache.http.HttpEntity;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchStatusException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
@@ -59,6 +58,11 @@
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.GetAllPitNodesResponse;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchRequest;
@@ -80,12 +84,14 @@
 import org.opensearch.client.tasks.TaskSubmissionResponse;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.rankeval.RankEvalRequest;
 import org.opensearch.index.rankeval.RankEvalResponse;
 import org.opensearch.index.reindex.BulkByScrollResponse;
@@ -94,7 +100,6 @@
 import org.opensearch.index.reindex.UpdateByQueryRequest;
 import org.opensearch.plugins.spi.NamedXContentProvider;
 import org.opensearch.rest.BytesRestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.mustache.MultiSearchTemplateRequest;
 import org.opensearch.script.mustache.MultiSearchTemplateResponse;
 import org.opensearch.script.mustache.SearchTemplateRequest;
@@ -108,10 +113,6 @@
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.filter.ParsedFilter;
 import org.opensearch.search.aggregations.bucket.filter.ParsedFilters;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.ParsedGeoHashGrid;
-import org.opensearch.search.aggregations.bucket.geogrid.ParsedGeoTileGrid;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.global.ParsedGlobal;
 import org.opensearch.search.aggregations.bucket.histogram.AutoDateHistogramAggregationBuilder;
@@ -138,24 +139,27 @@
 import org.opensearch.search.aggregations.bucket.range.RangeAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.sampler.InternalSampler;
 import org.opensearch.search.aggregations.bucket.sampler.ParsedSampler;
+import org.opensearch.search.aggregations.bucket.terms.DoubleTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongRareTerms;
+import org.opensearch.search.aggregations.bucket.terms.LongTerms;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.ParsedDoubleTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedLongRareTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedLongTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedMultiTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedSignificantLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedSignificantStringTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedStringRareTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedStringTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedUnsignedLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantStringTerms;
-import org.opensearch.search.aggregations.bucket.terms.DoubleTerms;
-import org.opensearch.search.aggregations.bucket.terms.LongTerms;
-import org.opensearch.search.aggregations.bucket.terms.ParsedDoubleTerms;
-import org.opensearch.search.aggregations.bucket.terms.ParsedLongTerms;
-import org.opensearch.search.aggregations.bucket.terms.ParsedStringTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
+import org.opensearch.search.aggregations.bucket.terms.UnsignedLongTerms;
 import org.opensearch.search.aggregations.metrics.AvgAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.CardinalityAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.ExtendedStatsAggregationBuilder;
-import org.opensearch.search.aggregations.metrics.GeoBoundsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.GeoCentroidAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentiles;
@@ -167,7 +171,6 @@
 import org.opensearch.search.aggregations.metrics.ParsedAvg;
 import org.opensearch.search.aggregations.metrics.ParsedCardinality;
 import org.opensearch.search.aggregations.metrics.ParsedExtendedStats;
-import org.opensearch.search.aggregations.metrics.ParsedGeoBounds;
 import org.opensearch.search.aggregations.metrics.ParsedGeoCentroid;
 import org.opensearch.search.aggregations.metrics.ParsedHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.ParsedHDRPercentiles;
@@ -267,6 +270,7 @@ public class RestHighLevelClient implements Closeable {
     private final IngestClient ingestClient = new IngestClient(this);
     private final SnapshotClient snapshotClient = new SnapshotClient(this);
     private final TasksClient tasksClient = new TasksClient(this);
+    private final SearchPipelineClient searchPipelineClient = new SearchPipelineClient(this);
 
     /**
      * Creates a {@link RestHighLevelClient} given the low level {@link RestClientBuilder} that allows to build the
@@ -353,6 +357,10 @@ public final TasksClient tasks() {
         return tasksClient;
     }
 
+    public final SearchPipelineClient searchPipeline() {
+        return searchPipelineClient;
+    }
+
     /**
      * Executes a bulk request using the Bulk API.
      * @param bulkRequest the request
@@ -1254,6 +1262,154 @@ public final Cancellable scrollAsync(
         );
     }
 
+    /**
+     * Create PIT context using create PIT API
+     *
+     * @param createPitRequest the request
+     * @param options          the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     */
+    public final CreatePitResponse createPit(CreatePitRequest createPitRequest, RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(
+            createPitRequest,
+            RequestConverters::createPit,
+            options,
+            CreatePitResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously Create PIT context using create PIT API
+     *
+     * @param createPitRequest the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return the response
+     */
+    public final Cancellable createPitAsync(
+        CreatePitRequest createPitRequest,
+        RequestOptions options,
+        ActionListener<CreatePitResponse> listener
+    ) {
+        return performRequestAsyncAndParseEntity(
+            createPitRequest,
+            RequestConverters::createPit,
+            options,
+            CreatePitResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
+    /**
+     * Delete point in time searches using delete PIT API
+     *
+     * @param deletePitRequest the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     */
+    public final DeletePitResponse deletePit(DeletePitRequest deletePitRequest, RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(
+            deletePitRequest,
+            RequestConverters::deletePit,
+            options,
+            DeletePitResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously Delete point in time searches using delete PIT API
+     *
+     * @param deletePitRequest the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return the response
+     */
+    public final Cancellable deletePitAsync(
+        DeletePitRequest deletePitRequest,
+        RequestOptions options,
+        ActionListener<DeletePitResponse> listener
+    ) {
+        return performRequestAsyncAndParseEntity(
+            deletePitRequest,
+            RequestConverters::deletePit,
+            options,
+            DeletePitResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
+    /**
+     * Delete all point in time searches using delete all PITs API
+     *
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     */
+    public final DeletePitResponse deleteAllPits(RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(
+            new MainRequest(),
+            (request) -> RequestConverters.deleteAllPits(),
+            options,
+            DeletePitResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously Delete all point in time searches using delete all PITs API
+     *
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return the response
+     */
+    public final Cancellable deleteAllPitsAsync(RequestOptions options, ActionListener<DeletePitResponse> listener) {
+        return performRequestAsyncAndParseEntity(
+            new MainRequest(),
+            (request) -> RequestConverters.deleteAllPits(),
+            options,
+            DeletePitResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
+    /**
+     * Get all point in time searches using list all PITs API
+     *
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     */
+    public final GetAllPitNodesResponse getAllPits(RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(
+            new MainRequest(),
+            (request) -> RequestConverters.getAllPits(),
+            options,
+            GetAllPitNodesResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously get all point in time searches using list all PITs API
+     *
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return the response
+     */
+    public final Cancellable getAllPitsAsync(RequestOptions options, ActionListener<GetAllPitNodesResponse> listener) {
+        return performRequestAsyncAndParseEntity(
+            new MainRequest(),
+            (request) -> RequestConverters.getAllPits(),
+            options,
+            GetAllPitNodesResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
     /**
      * Clears one or more scroll ids using the Clear Scroll API.
      *
@@ -1915,6 +2071,10 @@ private <Req, Resp> Cancellable internalPerformRequestAsync(
         ActionListener<Resp> listener,
         Set<Integer> ignores
     ) {
+        if (listener == null) {
+            throw new IllegalArgumentException("The listener is required and cannot be null");
+        }
+
         Request req;
         try {
             req = requestConverter.apply(request);
@@ -2067,11 +2227,11 @@ protected final <Resp> Resp parseEntity(final HttpEntity entity, final CheckedFu
         if (entity.getContentType() == null) {
             throw new IllegalStateException("OpenSearch didn't return the [Content-Type] header, unable to parse response body");
         }
-        XContentType xContentType = XContentType.fromMediaTypeOrFormat(entity.getContentType().getValue());
-        if (xContentType == null) {
+        MediaType medaiType = MediaType.fromMediaType(entity.getContentType().getValue());
+        if (medaiType == null) {
             throw new IllegalStateException("Unsupported Content-Type: " + entity.getContentType().getValue());
         }
-        try (XContentParser parser = xContentType.xContent().createParser(registry, DEPRECATION_HANDLER, entity.getContent())) {
+        try (XContentParser parser = medaiType.xContent().createParser(registry, DEPRECATION_HANDLER, entity.getContent())) {
             return entityParser.apply(parser);
         }
     }
@@ -2110,13 +2270,13 @@ static List<NamedXContentRegistry.Entry> getDefaultNamedXContents() {
         map.put(StatsBucketPipelineAggregationBuilder.NAME, (p, c) -> ParsedStatsBucket.fromXContent(p, (String) c));
         map.put(ExtendedStatsAggregationBuilder.NAME, (p, c) -> ParsedExtendedStats.fromXContent(p, (String) c));
         map.put(ExtendedStatsBucketPipelineAggregationBuilder.NAME, (p, c) -> ParsedExtendedStatsBucket.fromXContent(p, (String) c));
-        map.put(GeoBoundsAggregationBuilder.NAME, (p, c) -> ParsedGeoBounds.fromXContent(p, (String) c));
         map.put(GeoCentroidAggregationBuilder.NAME, (p, c) -> ParsedGeoCentroid.fromXContent(p, (String) c));
         map.put(HistogramAggregationBuilder.NAME, (p, c) -> ParsedHistogram.fromXContent(p, (String) c));
         map.put(DateHistogramAggregationBuilder.NAME, (p, c) -> ParsedDateHistogram.fromXContent(p, (String) c));
         map.put(AutoDateHistogramAggregationBuilder.NAME, (p, c) -> ParsedAutoDateHistogram.fromXContent(p, (String) c));
         map.put(VariableWidthHistogramAggregationBuilder.NAME, (p, c) -> ParsedVariableWidthHistogram.fromXContent(p, (String) c));
         map.put(StringTerms.NAME, (p, c) -> ParsedStringTerms.fromXContent(p, (String) c));
+        map.put(UnsignedLongTerms.NAME, (p, c) -> ParsedUnsignedLongTerms.fromXContent(p, (String) c));
         map.put(LongTerms.NAME, (p, c) -> ParsedLongTerms.fromXContent(p, (String) c));
         map.put(DoubleTerms.NAME, (p, c) -> ParsedDoubleTerms.fromXContent(p, (String) c));
         map.put(LongRareTerms.NAME, (p, c) -> ParsedLongRareTerms.fromXContent(p, (String) c));
@@ -2127,8 +2287,6 @@ static List<NamedXContentRegistry.Entry> getDefaultNamedXContents() {
         map.put(GlobalAggregationBuilder.NAME, (p, c) -> ParsedGlobal.fromXContent(p, (String) c));
         map.put(FilterAggregationBuilder.NAME, (p, c) -> ParsedFilter.fromXContent(p, (String) c));
         map.put(InternalSampler.PARSER_NAME, (p, c) -> ParsedSampler.fromXContent(p, (String) c));
-        map.put(GeoHashGridAggregationBuilder.NAME, (p, c) -> ParsedGeoHashGrid.fromXContent(p, (String) c));
-        map.put(GeoTileGridAggregationBuilder.NAME, (p, c) -> ParsedGeoTileGrid.fromXContent(p, (String) c));
         map.put(RangeAggregationBuilder.NAME, (p, c) -> ParsedRange.fromXContent(p, (String) c));
         map.put(DateRangeAggregationBuilder.NAME, (p, c) -> ParsedDateRange.fromXContent(p, (String) c));
         map.put(GeoDistanceAggregationBuilder.NAME, (p, c) -> ParsedGeoDistance.fromXContent(p, (String) c));
@@ -2140,6 +2298,7 @@ static List<NamedXContentRegistry.Entry> getDefaultNamedXContents() {
         map.put(IpRangeAggregationBuilder.NAME, (p, c) -> ParsedBinaryRange.fromXContent(p, (String) c));
         map.put(TopHitsAggregationBuilder.NAME, (p, c) -> ParsedTopHits.fromXContent(p, (String) c));
         map.put(CompositeAggregationBuilder.NAME, (p, c) -> ParsedComposite.fromXContent(p, (String) c));
+        map.put(MultiTermsAggregationBuilder.NAME, (p, c) -> ParsedMultiTerms.fromXContent(p, (String) c));
         List<NamedXContentRegistry.Entry> entries = map.entrySet()
             .stream()
             .map(entry -> new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(entry.getKey()), entry.getValue()))
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/RethrottleRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/RethrottleRequest.java
index 958e6ce4cda1c..6e453a5c7f343 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/RethrottleRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/RethrottleRequest.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client;
 
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 
 import java.util.Objects;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineClient.java
new file mode 100644
index 0000000000000..0014bdb8c8182
--- /dev/null
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineClient.java
@@ -0,0 +1,149 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client;
+
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineResponse;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.action.ActionListener;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import static java.util.Collections.emptySet;
+
+public final class SearchPipelineClient {
+    private final RestHighLevelClient restHighLevelClient;
+
+    SearchPipelineClient(RestHighLevelClient restHighLevelClient) {
+        this.restHighLevelClient = restHighLevelClient;
+    }
+
+    /**
+     * Add a pipeline or update an existing pipeline.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public AcknowledgedResponse put(PutSearchPipelineRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::putPipeline,
+            options,
+            AcknowledgedResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously add a pipeline or update an existing pipeline.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return cancellable that may be used to cancel the request
+     */
+    public Cancellable putAsync(PutSearchPipelineRequest request, RequestOptions options, ActionListener<AcknowledgedResponse> listener) {
+        return restHighLevelClient.performRequestAsyncAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::putPipeline,
+            options,
+            AcknowledgedResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
+    /**
+     * Get existing pipelines.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public GetSearchPipelineResponse get(GetSearchPipelineRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::getPipeline,
+            options,
+            GetSearchPipelineResponse::fromXContent,
+            Collections.singleton(404)
+        );
+    }
+
+    /**
+     * Asynchronously get existing pipelines.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return cancellable that may be used to cancel the request
+     */
+    public Cancellable getAsync(
+        GetSearchPipelineRequest request,
+        RequestOptions options,
+        ActionListener<GetSearchPipelineResponse> listener
+    ) {
+        return restHighLevelClient.performRequestAsyncAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::getPipeline,
+            options,
+            GetSearchPipelineResponse::fromXContent,
+            listener,
+            Collections.singleton(404)
+        );
+    }
+
+    /**
+     * Delete an existing pipeline.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public AcknowledgedResponse delete(DeleteSearchPipelineRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::deletePipeline,
+            options,
+            AcknowledgedResponse::fromXContent,
+            emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously delete an existing pipeline.
+     *
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return cancellable that may be used to cancel the request
+     */
+    public Cancellable deleteAsync(
+        DeleteSearchPipelineRequest request,
+        RequestOptions options,
+        ActionListener<AcknowledgedResponse> listener
+    ) {
+        return restHighLevelClient.performRequestAsyncAndParseEntity(
+            request,
+            SearchPipelineRequestConverters::deletePipeline,
+            options,
+            AcknowledgedResponse::fromXContent,
+            listener,
+            emptySet()
+        );
+    }
+
+}
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineRequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineRequestConverters.java
new file mode 100644
index 0000000000000..655e3728edd71
--- /dev/null
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineRequestConverters.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client;
+
+import org.apache.http.client.methods.HttpDelete;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPut;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+
+import java.io.IOException;
+
+final class SearchPipelineRequestConverters {
+    private SearchPipelineRequestConverters() {}
+
+    static Request putPipeline(PutSearchPipelineRequest putPipelineRequest) throws IOException {
+        String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_search/pipeline")
+            .addPathPart(putPipelineRequest.getId())
+            .build();
+        Request request = new Request(HttpPut.METHOD_NAME, endpoint);
+
+        RequestConverters.Params params = new RequestConverters.Params();
+        params.withTimeout(putPipelineRequest.timeout());
+        params.withMasterTimeout(putPipelineRequest.clusterManagerNodeTimeout());
+        request.addParameters(params.asMap());
+        request.setEntity(RequestConverters.createEntity(putPipelineRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
+        return request;
+    }
+
+    static Request deletePipeline(DeleteSearchPipelineRequest deletePipelineRequest) {
+        String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_search/pipeline")
+            .addPathPart(deletePipelineRequest.getId())
+            .build();
+        Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
+
+        RequestConverters.Params parameters = new RequestConverters.Params();
+        parameters.withTimeout(deletePipelineRequest.timeout());
+        parameters.withMasterTimeout(deletePipelineRequest.clusterManagerNodeTimeout());
+        request.addParameters(parameters.asMap());
+        return request;
+    }
+
+    static Request getPipeline(GetSearchPipelineRequest getPipelineRequest) {
+        String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_search/pipeline")
+            .addCommaSeparatedPathParts(getPipelineRequest.getIds())
+            .build();
+        Request request = new Request(HttpGet.METHOD_NAME, endpoint);
+
+        RequestConverters.Params parameters = new RequestConverters.Params();
+        parameters.withMasterTimeout(getPipelineRequest.clusterManagerNodeTimeout());
+        request.addParameters(parameters.asMap());
+        return request;
+    }
+}
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotClient.java
index 85a793dec24ce..87a0e45eafe49 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotClient.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequest;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryResponse;
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryRequest;
@@ -52,6 +51,7 @@
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusRequest;
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotRequestConverters.java b/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotRequestConverters.java
index 3c92bb5ec2ab8..357bb75d5fadb 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotRequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/SnapshotRequestConverters.java
@@ -47,7 +47,7 @@
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 
@@ -63,7 +63,7 @@ static Request getRepositories(GetRepositoriesRequest getRepositoriesRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(getRepositoriesRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(getRepositoriesRequest.clusterManagerNodeTimeout());
         parameters.withLocal(getRepositoriesRequest.local());
         request.addParameters(parameters.asMap());
         return request;
@@ -74,7 +74,7 @@ static Request createRepository(PutRepositoryRequest putRepositoryRequest) throw
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(putRepositoryRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(putRepositoryRequest.clusterManagerNodeTimeout());
         parameters.withTimeout(putRepositoryRequest.timeout());
         if (putRepositoryRequest.verify() == false) {
             parameters.putParam("verify", "false");
@@ -91,7 +91,7 @@ static Request deleteRepository(DeleteRepositoryRequest deleteRepositoryRequest)
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(deleteRepositoryRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(deleteRepositoryRequest.clusterManagerNodeTimeout());
         parameters.withTimeout(deleteRepositoryRequest.timeout());
         request.addParameters(parameters.asMap());
         return request;
@@ -105,7 +105,7 @@ static Request verifyRepository(VerifyRepositoryRequest verifyRepositoryRequest)
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(verifyRepositoryRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(verifyRepositoryRequest.clusterManagerNodeTimeout());
         parameters.withTimeout(verifyRepositoryRequest.timeout());
         request.addParameters(parameters.asMap());
         return request;
@@ -119,7 +119,7 @@ static Request cleanupRepository(CleanupRepositoryRequest cleanupRepositoryReque
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(cleanupRepositoryRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(cleanupRepositoryRequest.clusterManagerNodeTimeout());
         parameters.withTimeout(cleanupRepositoryRequest.timeout());
         request.addParameters(parameters.asMap());
         return request;
@@ -132,7 +132,7 @@ static Request createSnapshot(CreateSnapshotRequest createSnapshotRequest) throw
             .build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(createSnapshotRequest.masterNodeTimeout());
+        params.withMasterTimeout(createSnapshotRequest.clusterManagerNodeTimeout());
         params.withWaitForCompletion(createSnapshotRequest.waitForCompletion());
         request.addParameters(params.asMap());
         request.setEntity(RequestConverters.createEntity(createSnapshotRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -148,7 +148,7 @@ static Request cloneSnapshot(CloneSnapshotRequest cloneSnapshotRequest) throws I
             .build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         RequestConverters.Params params = new RequestConverters.Params();
-        params.withMasterTimeout(cloneSnapshotRequest.masterNodeTimeout());
+        params.withMasterTimeout(cloneSnapshotRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         request.setEntity(RequestConverters.createEntity(cloneSnapshotRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
         return request;
@@ -167,7 +167,7 @@ static Request getSnapshots(GetSnapshotsRequest getSnapshotsRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(getSnapshotsRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(getSnapshotsRequest.clusterManagerNodeTimeout());
         parameters.putParam("ignore_unavailable", Boolean.toString(getSnapshotsRequest.ignoreUnavailable()));
         parameters.putParam("verbose", Boolean.toString(getSnapshotsRequest.verbose()));
         request.addParameters(parameters.asMap());
@@ -183,7 +183,7 @@ static Request snapshotsStatus(SnapshotsStatusRequest snapshotsStatusRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(snapshotsStatusRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(snapshotsStatusRequest.clusterManagerNodeTimeout());
         parameters.withIgnoreUnavailable(snapshotsStatusRequest.ignoreUnavailable());
         request.addParameters(parameters.asMap());
         return request;
@@ -197,7 +197,7 @@ static Request restoreSnapshot(RestoreSnapshotRequest restoreSnapshotRequest) th
             .build();
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(restoreSnapshotRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(restoreSnapshotRequest.clusterManagerNodeTimeout());
         parameters.withWaitForCompletion(restoreSnapshotRequest.waitForCompletion());
         request.addParameters(parameters.asMap());
         request.setEntity(RequestConverters.createEntity(restoreSnapshotRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
@@ -212,7 +212,7 @@ static Request deleteSnapshot(DeleteSnapshotRequest deleteSnapshotRequest) {
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withMasterTimeout(deleteSnapshotRequest.masterNodeTimeout());
+        parameters.withMasterTimeout(deleteSnapshotRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/TasksClient.java b/client/rest-high-level/src/main/java/org/opensearch/client/TasksClient.java
index 51764e3339394..ec862aead794a 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/TasksClient.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/TasksClient.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.client.tasks.CancelTasksRequest;
 import org.opensearch.client.tasks.CancelTasksResponse;
 import org.opensearch.client.tasks.GetTaskRequest;
 import org.opensearch.client.tasks.GetTaskResponse;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.IOException;
 import java.util.Optional;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/TimedRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/TimedRequest.java
index 3310425df4662..dad5b6a3679ec 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/TimedRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/TimedRequest.java
@@ -44,10 +44,13 @@
 public abstract class TimedRequest implements Validatable {
 
     public static final TimeValue DEFAULT_ACK_TIMEOUT = timeValueSeconds(30);
-    public static final TimeValue DEFAULT_MASTER_NODE_TIMEOUT = TimeValue.timeValueSeconds(30);
+    public static final TimeValue DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT = TimeValue.timeValueSeconds(30);
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT} */
+    @Deprecated
+    public static final TimeValue DEFAULT_MASTER_NODE_TIMEOUT = DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
 
     private TimeValue timeout = DEFAULT_ACK_TIMEOUT;
-    private TimeValue masterTimeout = DEFAULT_MASTER_NODE_TIMEOUT;
+    private TimeValue clusterManagerTimeout = DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
 
     /**
      * Sets the timeout to wait for the all the nodes to acknowledge
@@ -58,11 +61,21 @@ public void setTimeout(TimeValue timeout) {
     }
 
     /**
-     * Sets the timeout to connect to the master node
-     * @param masterTimeout timeout as a {@link TimeValue}
+     * Sets the timeout to connect to the cluster-manager node
+     * @param clusterManagerTimeout timeout as a {@link TimeValue}
      */
-    public void setMasterTimeout(TimeValue masterTimeout) {
-        this.masterTimeout = masterTimeout;
+    public void setClusterManagerTimeout(TimeValue clusterManagerTimeout) {
+        this.clusterManagerTimeout = clusterManagerTimeout;
+    }
+
+    /**
+     * Sets the timeout to connect to the cluster-manager node
+     * @param clusterManagerTimeout timeout as a {@link TimeValue}
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerTimeout(TimeValue)}
+     */
+    @Deprecated
+    public void setMasterTimeout(TimeValue clusterManagerTimeout) {
+        setClusterManagerTimeout(clusterManagerTimeout);
     }
 
     /**
@@ -73,9 +86,18 @@ public TimeValue timeout() {
     }
 
     /**
-     * Returns the timeout for the request to be completed on the master node
+     * Returns the timeout for the request to be completed on the cluster-manager node
+     */
+    public TimeValue clusterManagerNodeTimeout() {
+        return clusterManagerTimeout;
+    }
+
+    /**
+     * Returns the timeout for the request to be completed on the cluster-manager node
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout()}
      */
+    @Deprecated
     public TimeValue masterNodeTimeout() {
-        return masterTimeout;
+        return clusterManagerNodeTimeout();
     }
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteConnectionInfo.java b/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteConnectionInfo.java
index 4f91d32452d26..28eeae7b52554 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteConnectionInfo.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteConnectionInfo.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.client.cluster;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * This class encapsulates all remote cluster information to be rendered on
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteInfoResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteInfoResponse.java
index 388bcd3be51e4..d1fa2eb1dff0d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteInfoResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/cluster/RemoteInfoResponse.java
@@ -31,14 +31,14 @@
 
 package org.opensearch.client.cluster;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A response to _remote/info API request.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/AcknowledgedResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/AcknowledgedResponse.java
index c54bef15d4876..73e6e4a638020 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/AcknowledgedResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/AcknowledgedResponse.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.function.Function;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class AcknowledgedResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/BroadcastResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/BroadcastResponse.java
index dc46b3fbcc941..a91d1461685f8 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/BroadcastResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/BroadcastResponse.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collection;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/CountRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/CountRequest.java
index 88d0fee69a870..22be6c2e7ac9d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/CountRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/CountRequest.java
@@ -36,9 +36,9 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.internal.SearchContext;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/CountResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/CountResponse.java
index 1d67a50f68f40..eeb99cbca2b5f 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/CountResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/CountResponse.java
@@ -33,16 +33,16 @@
 package org.opensearch.client.core;
 
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A response to _count API request.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/GetSourceResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/GetSourceResponse.java
index 7d3b327d15902..57a88426f6f95 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/GetSourceResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/GetSourceResponse.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/IndexerJobStats.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/IndexerJobStats.java
index b0cc46b80afc8..38e30c08a04e1 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/IndexerJobStats.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/IndexerJobStats.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 
 import java.util.Objects;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/MainResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/MainResponse.java
index b15ef2e699ca5..6df51a6a4ff3e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/MainResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/MainResponse.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Objects;
 
@@ -43,7 +43,9 @@ public class MainResponse {
     private static final ConstructingObjectParser<MainResponse, Void> PARSER = new ConstructingObjectParser<>(
         MainResponse.class.getName(),
         true,
-        args -> { return new MainResponse((String) args[0], (Version) args[1], (String) args[2], (String) args[3]); }
+        args -> {
+            return new MainResponse((String) args[0], (Version) args[1], (String) args[2], (String) args[3]);
+        }
     );
 
     static {
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsRequest.java
index fdb8967dfa605..7c70d977d320c 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsRequest.java
@@ -33,8 +33,8 @@
 package org.opensearch.client.core;
 
 import org.opensearch.client.Validatable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsResponse.java
index 490c5e314a513..1dd5bdb6f30f8 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/MultiTermVectorsResponse.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class MultiTermVectorsResponse {
     private final List<TermVectorsResponse> responses;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/PageParams.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/PageParams.java
index 38b287a87d412..7f684624b8aa7 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/PageParams.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/PageParams.java
@@ -32,10 +32,10 @@
 package org.opensearch.client.core;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/ShardsAcknowledgedResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/ShardsAcknowledgedResponse.java
index df228d3d84f60..3d097de47afb3 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/ShardsAcknowledgedResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/ShardsAcknowledgedResponse.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class ShardsAcknowledgedResponse extends AcknowledgedResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsRequest.java
index b346667f462c4..c58114299c065 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsRequest.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.client.Validatable;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsResponse.java
index fa13abf72207e..ad2e3dd550880 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/core/TermVectorsResponse.java
@@ -33,17 +33,18 @@
 package org.opensearch.client.core;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Collections;
-import java.util.List;
 import java.util.Comparator;
+import java.util.List;
 import java.util.Objects;
 
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+
 public class TermVectorsResponse {
     private final String index;
     private final String id;
@@ -240,7 +241,9 @@ public static final class FieldStatistics {
             private static final ConstructingObjectParser<FieldStatistics, Void> PARSER = new ConstructingObjectParser<>(
                 "field_statistics",
                 true,
-                args -> { return new FieldStatistics((long) args[0], (int) args[1], (long) args[2]); }
+                args -> {
+                    return new FieldStatistics((long) args[0], (int) args[1], (long) args[2]);
+                }
             );
 
             static {
@@ -411,11 +414,9 @@ public int hashCode() {
 
         public static final class Token {
 
-            private static final ConstructingObjectParser<Token, Void> PARSER = new ConstructingObjectParser<>(
-                "token",
-                true,
-                args -> { return new Token((Integer) args[0], (Integer) args[1], (Integer) args[2], (String) args[3]); }
-            );
+            private static final ConstructingObjectParser<Token, Void> PARSER = new ConstructingObjectParser<>("token", true, args -> {
+                return new Token((Integer) args[0], (Integer) args[1], (Integer) args[2], (String) args[3]);
+            });
             static {
                 PARSER.declareInt(optionalConstructorArg(), new ParseField("start_offset"));
                 PARSER.declareInt(optionalConstructorArg(), new ParseField("end_offset"));
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeRequest.java
index b614e30d63ddd..a2b69962c392e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeRequest.java
@@ -33,11 +33,11 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.client.Validatable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeResponse.java
index cc173a5b8ab6f..359e6e6617c98 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/AnalyzeResponse.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -43,7 +43,7 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 public class AnalyzeResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CloseIndexResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CloseIndexResponse.java
index 817d1c08532c6..e32c33484140d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CloseIndexResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CloseIndexResponse.java
@@ -32,21 +32,21 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.util.List;
 import java.util.Objects;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableList;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
-import static org.opensearch.common.xcontent.ObjectParser.ValueType;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ObjectParser.ValueType;
 
 public class CloseIndexResponse extends ShardsAcknowledgedResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComponentTemplatesExistRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComponentTemplatesExistRequest.java
index 4a518d851cdd8..98395626ef392 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComponentTemplatesExistRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComponentTemplatesExistRequest.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /**
  * A request to check for the existence of component templates
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComposableIndexTemplateExistRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComposableIndexTemplateExistRequest.java
index 4efe0e6b33aac..a9297d0dd0559 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComposableIndexTemplateExistRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ComposableIndexTemplateExistRequest.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /**
  * A request to check for the existence of index templates
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexRequest.java
index 5bf65a6ea1989..7805a7853b003 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexRequest.java
@@ -38,19 +38,19 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.client.TimedRequest;
 import org.opensearch.client.Validatable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -64,6 +64,8 @@
 
 /**
  * A request to create an index.
+ *
+ * @opensearch.api
  */
 public class CreateIndexRequest extends TimedRequest implements Validatable, ToXContentObject {
     static final ParseField MAPPINGS = new ParseField("mappings");
@@ -74,7 +76,7 @@ public class CreateIndexRequest extends TimedRequest implements Validatable, ToX
     private Settings settings = EMPTY_SETTINGS;
 
     private BytesReference mappings;
-    private XContentType mappingsXContentType;
+    private MediaType mappingsMediaType;
 
     private final Set<Alias> aliases = new HashSet<>();
 
@@ -123,8 +125,8 @@ public CreateIndexRequest settings(Settings settings) {
     /**
      * The settings to create the index with (either json or yaml format)
      */
-    public CreateIndexRequest settings(String source, XContentType xContentType) {
-        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+    public CreateIndexRequest settings(String source, MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -132,7 +134,7 @@ public CreateIndexRequest settings(String source, XContentType xContentType) {
      * Allows to set the settings using a json builder.
      */
     public CreateIndexRequest settings(XContentBuilder builder) {
-        settings(Strings.toString(builder), builder.contentType());
+        settings(builder.toString(), builder.contentType());
         return this;
     }
 
@@ -148,8 +150,8 @@ public BytesReference mappings() {
         return mappings;
     }
 
-    public XContentType mappingsXContentType() {
-        return mappingsXContentType;
+    public MediaType mappingsMediaType() {
+        return mappingsMediaType;
     }
 
     /**
@@ -158,10 +160,10 @@ public XContentType mappingsXContentType() {
      * Note that the definition should *not* be nested under a type name.
      *
      * @param source The mapping source
-     * @param xContentType The content type of the source
+     * @param mediaType The media type of the source
      */
-    public CreateIndexRequest mapping(String source, XContentType xContentType) {
-        return mapping(new BytesArray(source), xContentType);
+    public CreateIndexRequest mapping(String source, MediaType mediaType) {
+        return mapping(new BytesArray(source), mediaType);
     }
 
     /**
@@ -184,7 +186,7 @@ public CreateIndexRequest mapping(XContentBuilder source) {
      */
     public CreateIndexRequest mapping(Map<String, ?> source) {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.getDefaultMediaType());
             builder.map(source);
             return mapping(BytesReference.bytes(builder), builder.contentType());
         } catch (IOException e) {
@@ -198,12 +200,12 @@ public CreateIndexRequest mapping(Map<String, ?> source) {
      * Note that the definition should *not* be nested under a type name.
      *
      * @param source The mapping source
-     * @param xContentType the content type of the mapping source
+     * @param mediaType the content type of the mapping source
      */
-    public CreateIndexRequest mapping(BytesReference source, XContentType xContentType) {
-        Objects.requireNonNull(xContentType);
+    public CreateIndexRequest mapping(BytesReference source, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
         mappings = source;
-        mappingsXContentType = xContentType;
+        mappingsMediaType = mediaType;
         return this;
     }
 
@@ -234,14 +236,14 @@ public CreateIndexRequest aliases(XContentBuilder source) {
     /**
      * Sets the aliases that will be associated with the index when it gets created
      */
-    public CreateIndexRequest aliases(String source, XContentType contentType) {
-        return aliases(new BytesArray(source), contentType);
+    public CreateIndexRequest aliases(String source, MediaType mediaType) {
+        return aliases(new BytesArray(source), mediaType);
     }
 
     /**
      * Sets the aliases that will be associated with the index when it gets created
      */
-    public CreateIndexRequest aliases(BytesReference source, XContentType contentType) {
+    public CreateIndexRequest aliases(BytesReference source, MediaType contentType) {
         // EMPTY is safe here because we never call namedObject
         try (
             XContentParser parser = XContentHelper.createParser(
@@ -283,8 +285,8 @@ public CreateIndexRequest aliases(Collection<Alias> aliases) {
      *
      * Note that the mapping definition should *not* be nested under a type name.
      */
-    public CreateIndexRequest source(String source, XContentType xContentType) {
-        return source(new BytesArray(source), xContentType);
+    public CreateIndexRequest source(String source, MediaType mediaType) {
+        return source(new BytesArray(source), mediaType);
     }
 
     /**
@@ -301,9 +303,9 @@ public CreateIndexRequest source(XContentBuilder source) {
      *
      * Note that the mapping definition should *not* be nested under a type name.
      */
-    public CreateIndexRequest source(BytesReference source, XContentType xContentType) {
-        Objects.requireNonNull(xContentType);
-        source(XContentHelper.convertToMap(source, false, xContentType).v2());
+    public CreateIndexRequest source(BytesReference source, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
+        source(XContentHelper.convertToMap(source, false, mediaType).v2());
         return this;
     }
 
@@ -365,7 +367,7 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
 
         if (mappings != null) {
             try (InputStream stream = mappings.streamInput()) {
-                builder.rawField(MAPPINGS.getPreferredName(), stream, mappingsXContentType);
+                builder.rawField(MAPPINGS.getPreferredName(), stream, mappingsMediaType);
             }
         }
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexResponse.java
index 7e1ea2894961d..21e2ba4b342a6 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/CreateIndexResponse.java
@@ -33,14 +33,14 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A response for a create index action.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStream.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStream.java
index e87a77dafdde1..0166dad4a4077 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStream.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStream.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStreamsStatsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStreamsStatsResponse.java
index fc3a7b5b4fac5..327836160cceb 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStreamsStatsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DataStreamsStatsResponse.java
@@ -33,11 +33,11 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.client.core.BroadcastResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -45,7 +45,7 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class DataStreamsStatsResponse extends BroadcastResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DetailAnalyzeResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DetailAnalyzeResponse.java
index 00fa6fb046cf2..92ab2d7b744b2 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/DetailAnalyzeResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/DetailAnalyzeResponse.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 public class DetailAnalyzeResponse {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesRequest.java
index f70682fee3763..6326e8edf763b 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesRequest.java
@@ -44,7 +44,7 @@ public class GetComponentTemplatesRequest implements Validatable {
 
     private final String name;
 
-    private TimeValue masterNodeTimeout = TimedRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+    private TimeValue clusterManagerNodeTimeout = TimedRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
     private boolean local = false;
 
     /**
@@ -65,23 +65,47 @@ public String name() {
     }
 
     /**
-     * @return the timeout for waiting for the master node to respond
+     * @return the timeout for waiting for the cluster-manager node to respond
      */
+    public TimeValue getClusterManagerNodeTimeout() {
+        return clusterManagerNodeTimeout;
+    }
+
+    /**
+     * @return the timeout for waiting for the cluster-manager node to respond
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getMasterNodeTimeout()}
+     */
+    @Deprecated
     public TimeValue getMasterNodeTimeout() {
-        return masterNodeTimeout;
+        return getClusterManagerNodeTimeout();
+    }
+
+    public void setClusterManagerNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        this.clusterManagerNodeTimeout = clusterManagerNodeTimeout;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(TimeValue)} */
+    @Deprecated
+    public void setMasterNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
-    public void setMasterNodeTimeout(@Nullable TimeValue masterNodeTimeout) {
-        this.masterNodeTimeout = masterNodeTimeout;
+    public void setClusterManagerNodeTimeout(String clusterManagerNodeTimeout) {
+        final TimeValue timeValue = TimeValue.parseTimeValue(
+            clusterManagerNodeTimeout,
+            getClass().getSimpleName() + ".clusterManagerNodeTimeout"
+        );
+        setClusterManagerNodeTimeout(timeValue);
     }
 
-    public void setMasterNodeTimeout(String masterNodeTimeout) {
-        final TimeValue timeValue = TimeValue.parseTimeValue(masterNodeTimeout, getClass().getSimpleName() + ".masterNodeTimeout");
-        setMasterNodeTimeout(timeValue);
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(String)} */
+    @Deprecated
+    public void setMasterNodeTimeout(String clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
     /**
-     * @return true if this request is to read from the local cluster state, rather than the master node - false otherwise
+     * @return true if this request is to read from the local cluster state, rather than the cluster-manager node - false otherwise
      */
     public boolean isLocal() {
         return local;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesResponse.java
index 8f6ebbc8349d5..a5117c5db4edb 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComponentTemplatesResponse.java
@@ -32,9 +32,9 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.cluster.metadata.ComponentTemplate;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplateRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplateRequest.java
index 572a5eeec2d23..73f6f15fc7a78 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplateRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplateRequest.java
@@ -44,7 +44,7 @@ public class GetComposableIndexTemplateRequest implements Validatable {
 
     private final String name;
 
-    private TimeValue masterNodeTimeout = TimedRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+    private TimeValue clusterManagerNodeTimeout = TimedRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
     private boolean local = false;
 
     /**
@@ -65,23 +65,47 @@ public String name() {
     }
 
     /**
-     * @return the timeout for waiting for the master node to respond
+     * @return the timeout for waiting for the cluster-manager node to respond
      */
+    public TimeValue getClusterManagerNodeTimeout() {
+        return clusterManagerNodeTimeout;
+    }
+
+    /**
+     * @return the timeout for waiting for the cluster-manager node to respond
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getMasterNodeTimeout()}
+     */
+    @Deprecated
     public TimeValue getMasterNodeTimeout() {
-        return masterNodeTimeout;
+        return getClusterManagerNodeTimeout();
+    }
+
+    public void setClusterManagerNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        this.clusterManagerNodeTimeout = clusterManagerNodeTimeout;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(TimeValue)} */
+    @Deprecated
+    public void setMasterNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
-    public void setMasterNodeTimeout(@Nullable TimeValue masterNodeTimeout) {
-        this.masterNodeTimeout = masterNodeTimeout;
+    public void setClusterManagerNodeTimeout(String clusterManagerNodeTimeout) {
+        final TimeValue timeValue = TimeValue.parseTimeValue(
+            clusterManagerNodeTimeout,
+            getClass().getSimpleName() + ".clusterManagerNodeTimeout"
+        );
+        setClusterManagerNodeTimeout(timeValue);
     }
 
-    public void setMasterNodeTimeout(String masterNodeTimeout) {
-        final TimeValue timeValue = TimeValue.parseTimeValue(masterNodeTimeout, getClass().getSimpleName() + ".masterNodeTimeout");
-        setMasterNodeTimeout(timeValue);
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(String)} */
+    @Deprecated
+    public void setMasterNodeTimeout(String clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
     /**
-     * @return true if this request is to read from the local cluster state, rather than the master node - false otherwise
+     * @return true if this request is to read from the local cluster state, rather than the cluster-manager node - false otherwise
      */
     public boolean isLocal() {
         return local;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponse.java
index 96ba7e675253a..9e05725660e96 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponse.java
@@ -32,9 +32,9 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetDataStreamResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetDataStreamResponse.java
index 81fde3ebf2114..54633f9558f5c 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetDataStreamResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetDataStreamResponse.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsRequest.java
index 19792001170f3..70eae3a360005 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsRequest.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.Validatable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /** Request the mappings of specific fields */
 public class GetFieldMappingsRequest implements Validatable {
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsResponse.java
index c3d9679fc485b..ec3101b7e7543 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetFieldMappingsResponse.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.Mapper;
 
 import java.io.IOException;
@@ -47,9 +47,9 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /** Response object for {@link GetFieldMappingsRequest} API */
 public class GetFieldMappingsResponse {
@@ -150,7 +150,7 @@ public String fullName() {
          * Returns the mappings as a map. Note that the returned map has a single key which is always the field's {@link Mapper#name}.
          */
         public Map<String, Object> sourceAsMap() {
-            return XContentHelper.convertToMap(source, true, XContentType.JSON).v2();
+            return XContentHelper.convertToMap(source, true, MediaTypeRegistry.JSON).v2();
         }
 
         // pkg-private for testing
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexRequest.java
index 5e5ab6aeae305..c5ef5cb9c1795 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexRequest.java
@@ -82,9 +82,9 @@ public final GetIndexRequest local(boolean local) {
     }
 
     /**
-     * Return local information, do not retrieve the state from master node (default: false).
+     * Return local information, do not retrieve the state from cluster-manager node (default: false).
      * @return <code>true</code> if local information is to be returned;
-     * <code>false</code> if information is to be retrieved from master node (default).
+     * <code>false</code> if information is to be retrieved from cluster-manager node (default).
      */
     public final boolean local() {
         return local;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexResponse.java
index 4fa87a28784aa..6ec1c312c9ba9 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexResponse.java
@@ -36,8 +36,8 @@
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -49,7 +49,7 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A client side response for a get index action.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesRequest.java
index 071bcc7a75a71..dc1759a7272e8 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesRequest.java
@@ -35,8 +35,8 @@
 import org.opensearch.client.TimedRequest;
 import org.opensearch.client.Validatable;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 
 import java.util.Arrays;
 import java.util.List;
@@ -51,7 +51,7 @@ public class GetIndexTemplatesRequest implements Validatable {
 
     private final List<String> names;
 
-    private TimeValue masterNodeTimeout = TimedRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+    private TimeValue clusterManagerNodeTimeout = TimedRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
     private boolean local = false;
 
     /**
@@ -84,23 +84,47 @@ public List<String> names() {
     }
 
     /**
-     * @return the timeout for waiting for the master node to respond
+     * @return the timeout for waiting for the cluster-manager node to respond
      */
+    public TimeValue getClusterManagerNodeTimeout() {
+        return clusterManagerNodeTimeout;
+    }
+
+    /**
+     * @return the timeout for waiting for the cluster-manager node to respond
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getMasterNodeTimeout()}
+     */
+    @Deprecated
     public TimeValue getMasterNodeTimeout() {
-        return masterNodeTimeout;
+        return getClusterManagerNodeTimeout();
+    }
+
+    public void setClusterManagerNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        this.clusterManagerNodeTimeout = clusterManagerNodeTimeout;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(TimeValue)} */
+    @Deprecated
+    public void setMasterNodeTimeout(@Nullable TimeValue clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
-    public void setMasterNodeTimeout(@Nullable TimeValue masterNodeTimeout) {
-        this.masterNodeTimeout = masterNodeTimeout;
+    public void setClusterManagerNodeTimeout(String clusterManagerNodeTimeout) {
+        final TimeValue timeValue = TimeValue.parseTimeValue(
+            clusterManagerNodeTimeout,
+            getClass().getSimpleName() + ".clusterManagerNodeTimeout"
+        );
+        setClusterManagerNodeTimeout(timeValue);
     }
 
-    public void setMasterNodeTimeout(String masterNodeTimeout) {
-        final TimeValue timeValue = TimeValue.parseTimeValue(masterNodeTimeout, getClass().getSimpleName() + ".masterNodeTimeout");
-        setMasterNodeTimeout(timeValue);
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(String)} */
+    @Deprecated
+    public void setMasterNodeTimeout(String clusterManagerNodeTimeout) {
+        setClusterManagerNodeTimeout(clusterManagerNodeTimeout);
     }
 
     /**
-     * @return true if this request is to read from the local cluster state, rather than the master node - false otherwise
+     * @return true if this request is to read from the local cluster state, rather than the cluster-manager node - false otherwise
      */
     public boolean isLocal() {
         return local;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesResponse.java
index 84ee4c25409e0..25bdc2191b6d3 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetIndexTemplatesResponse.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsRequest.java
index e049e70c7587c..2e5b0cb89cedb 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsRequest.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.TimedRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 public class GetMappingsRequest extends TimedRequest {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsResponse.java
index 85841d9e28dc7..8257eb02e9ac1 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/GetMappingsResponse.java
@@ -33,9 +33,9 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/IndexTemplateMetadata.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/IndexTemplateMetadata.java
index 63ffae0bd4abb..017ad0089704e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/IndexTemplateMetadata.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/IndexTemplateMetadata.java
@@ -35,21 +35,22 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
 import java.util.AbstractMap;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 public class IndexTemplateMetadata {
 
@@ -59,9 +60,7 @@ public class IndexTemplateMetadata {
         true,
         (a, name) -> {
             List<Map.Entry<String, AliasMetadata>> alias = (List<Map.Entry<String, AliasMetadata>>) a[5];
-            ImmutableOpenMap<String, AliasMetadata> aliasMap = new ImmutableOpenMap.Builder<String, AliasMetadata>().putAll(
-                alias.stream().collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))
-            ).build();
+            final Map<String, AliasMetadata> aliasMap = alias.stream().collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
             return new IndexTemplateMetadata(
                 name,
                 (Integer) a[0],
@@ -128,7 +127,7 @@ public class IndexTemplateMetadata {
 
     private final MappingMetadata mappings;
 
-    private final ImmutableOpenMap<String, AliasMetadata> aliases;
+    private final Map<String, AliasMetadata> aliases;
 
     public IndexTemplateMetadata(
         String name,
@@ -137,7 +136,7 @@ public IndexTemplateMetadata(
         List<String> patterns,
         Settings settings,
         MappingMetadata mappings,
-        ImmutableOpenMap<String, AliasMetadata> aliases
+        final Map<String, AliasMetadata> aliases
     ) {
         if (patterns == null || patterns.isEmpty()) {
             throw new IllegalArgumentException("Index patterns must not be null or empty; got " + patterns);
@@ -148,7 +147,7 @@ public IndexTemplateMetadata(
         this.patterns = patterns;
         this.settings = settings;
         this.mappings = mappings;
-        this.aliases = aliases;
+        this.aliases = Collections.unmodifiableMap(aliases);
     }
 
     public String name() {
@@ -176,7 +175,7 @@ public MappingMetadata mappings() {
         return this.mappings;
     }
 
-    public ImmutableOpenMap<String, AliasMetadata> aliases() {
+    public Map<String, AliasMetadata> aliases() {
         return this.aliases;
     }
 
@@ -217,12 +216,12 @@ public static class Builder {
 
         private MappingMetadata mappings;
 
-        private final ImmutableOpenMap.Builder<String, AliasMetadata> aliases;
+        private final Map<String, AliasMetadata> aliases;
 
         public Builder(String name) {
             this.name = name;
             mappings = null;
-            aliases = ImmutableOpenMap.builder();
+            aliases = new HashMap<>();
         }
 
         public Builder(IndexTemplateMetadata indexTemplateMetadata) {
@@ -233,7 +232,7 @@ public Builder(IndexTemplateMetadata indexTemplateMetadata) {
             settings(indexTemplateMetadata.settings());
 
             mappings = indexTemplateMetadata.mappings();
-            aliases = ImmutableOpenMap.builder(indexTemplateMetadata.aliases());
+            aliases = new HashMap<>(indexTemplateMetadata.aliases());
         }
 
         public Builder order(int order) {
@@ -277,7 +276,7 @@ public Builder putAlias(AliasMetadata.Builder aliasMetadata) {
         }
 
         public IndexTemplateMetadata build() {
-            return new IndexTemplateMetadata(name, order, version, indexPatterns, settings, mappings, aliases.build());
+            return new IndexTemplateMetadata(name, order, version, indexPatterns, settings, mappings, aliases);
         }
 
         public static IndexTemplateMetadata fromXContent(XContentParser parser, String templateName) throws IOException {
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComponentTemplateRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComponentTemplateRequest.java
index e895cc71c4471..cfcd594658ea1 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComponentTemplateRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComponentTemplateRequest.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.client.TimedRequest;
 import org.opensearch.cluster.metadata.ComponentTemplate;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComposableIndexTemplateRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComposableIndexTemplateRequest.java
index c8fa70e9f8738..309519d6f7b76 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComposableIndexTemplateRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutComposableIndexTemplateRequest.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.client.TimedRequest;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutIndexTemplateRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutIndexTemplateRequest.java
index f248e8efa24f4..d090a469d2735 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutIndexTemplateRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutIndexTemplateRequest.java
@@ -37,21 +37,23 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -69,7 +71,10 @@
 /**
  * A request to create an index template.
  */
-public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateRequest> implements IndicesRequest, ToXContentFragment {
+public class PutIndexTemplateRequest extends ClusterManagerNodeRequest<PutIndexTemplateRequest>
+    implements
+        IndicesRequest,
+        ToXContentFragment {
 
     private String name;
 
@@ -212,10 +217,10 @@ public Settings settings() {
      * Adds mapping that will be added when the index gets created.
      *
      * @param source The mapping source
-     * @param xContentType The type of content contained within the source
+     * @param mediaType The type of content contained within the source
      */
-    public PutIndexTemplateRequest mapping(String source, XContentType xContentType) {
-        internalMapping(XContentHelper.convertToMap(new BytesArray(source), true, xContentType).v2());
+    public PutIndexTemplateRequest mapping(String source, MediaType mediaType) {
+        internalMapping(XContentHelper.convertToMap(new BytesArray(source), true, mediaType).v2());
         return this;
     }
 
@@ -263,11 +268,12 @@ public PutIndexTemplateRequest mapping(Map<String, Object> source) {
 
     private PutIndexTemplateRequest internalMapping(Map<String, Object> source) {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
             builder.map(source);
-            Objects.requireNonNull(builder.contentType());
+            MediaType mediaType = builder.contentType();
+            Objects.requireNonNull(mediaType);
             try {
-                mappings = new BytesArray(XContentHelper.convertToJson(BytesReference.bytes(builder), false, false, builder.contentType()));
+                mappings = new BytesArray(XContentHelper.convertToJson(BytesReference.bytes(builder), false, false, mediaType));
                 return this;
             } catch (IOException e) {
                 throw new UncheckedIOException("failed to convert source to json", e);
@@ -339,7 +345,10 @@ public PutIndexTemplateRequest source(Map<String, Object> templateSource) {
 
     /**
      * The template source definition.
+     *
+     * @deprecated use {@link #source(String, MediaType)} instead
      */
+    @Deprecated
     public PutIndexTemplateRequest source(String templateSource, XContentType xContentType) {
         return source(XContentHelper.convertToMap(xContentType.xContent(), templateSource, true));
     }
@@ -347,6 +356,16 @@ public PutIndexTemplateRequest source(String templateSource, XContentType xConte
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(String templateSource, MediaType mediaType) {
+        return source(XContentHelper.convertToMap(mediaType.xContent(), templateSource, true));
+    }
+
+    /**
+     * The template source definition.
+     *
+     * @deprecated use {@link #source(byte[], MediaType)} instead
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(byte[] source, XContentType xContentType) {
         return source(source, 0, source.length, xContentType);
     }
@@ -354,6 +373,16 @@ public PutIndexTemplateRequest source(byte[] source, XContentType xContentType)
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(byte[] source, MediaType mediaType) {
+        return source(source, 0, source.length, mediaType);
+    }
+
+    /**
+     * The template source definition.
+     *
+     * @deprecated use {@link #source(byte[], int, int, MediaType)} instead
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(byte[] source, int offset, int length, XContentType xContentType) {
         return source(new BytesArray(source, offset, length), xContentType);
     }
@@ -361,10 +390,27 @@ public PutIndexTemplateRequest source(byte[] source, int offset, int length, XCo
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(byte[] source, int offset, int length, MediaType mediaType) {
+        return source(new BytesArray(source, offset, length), mediaType);
+    }
+
+    /**
+     * The template source definition.
+     *
+     * @deprecated use {@link #source(BytesReference, MediaType)} instead
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(BytesReference source, XContentType xContentType) {
         return source(XContentHelper.convertToMap(source, true, xContentType).v2());
     }
 
+    /**
+     * The template source definition.
+     */
+    public PutIndexTemplateRequest source(BytesReference source, MediaType mediaType) {
+        return source(XContentHelper.convertToMap(source, true, mediaType).v2());
+    }
+
     public Set<Alias> aliases() {
         return this.aliases;
     }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutMappingRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutMappingRequest.java
index c8d5e4c95782a..6d7e95d191ba6 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutMappingRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/PutMappingRequest.java
@@ -36,13 +36,13 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.TimedRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -52,6 +52,8 @@
  * Put a mapping definition into one or more indices. If an index already contains mappings,
  * the new mappings will be merged with the existing one. If there are elements that cannot
  * be merged, the request will be rejected.
+ *
+ * @opensearch.api
  */
 public class PutMappingRequest extends TimedRequest implements IndicesRequest, ToXContentObject {
 
@@ -59,7 +61,7 @@ public class PutMappingRequest extends TimedRequest implements IndicesRequest, T
     private IndicesOptions indicesOptions = IndicesOptions.fromOptions(false, false, true, true);
 
     private BytesReference source;
-    private XContentType xContentType;
+    private MediaType mediaType;
 
     /**
      * Constructs a new put mapping request against one or more indices. If no indices
@@ -95,10 +97,10 @@ public BytesReference source() {
     }
 
     /**
-     * The {@link XContentType} of the mapping source.
+     * The {@link MediaType} of the mapping source.
      */
-    public XContentType xContentType() {
-        return xContentType;
+    public MediaType mediaType() {
+        return mediaType;
     }
 
     /**
@@ -108,7 +110,7 @@ public XContentType xContentType() {
      */
     public PutMappingRequest source(Map<String, ?> mappingSource) {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.getDefaultMediaType());
             builder.map(mappingSource);
             return source(builder);
         } catch (IOException e) {
@@ -121,9 +123,9 @@ public PutMappingRequest source(Map<String, ?> mappingSource) {
      *
      * Note that the definition should *not* be nested under a type name.
      */
-    public PutMappingRequest source(String mappingSource, XContentType xContentType) {
+    public PutMappingRequest source(String mappingSource, MediaType mediaType) {
         this.source = new BytesArray(mappingSource);
-        this.xContentType = xContentType;
+        this.mediaType = mediaType;
         return this;
     }
 
@@ -134,7 +136,7 @@ public PutMappingRequest source(String mappingSource, XContentType xContentType)
      */
     public PutMappingRequest source(XContentBuilder builder) {
         this.source = BytesReference.bytes(builder);
-        this.xContentType = builder.contentType();
+        this.mediaType = builder.contentType();
         return this;
     }
 
@@ -143,9 +145,9 @@ public PutMappingRequest source(XContentBuilder builder) {
      *
      * Note that the definition should *not* be nested under a type name.
      */
-    public PutMappingRequest source(BytesReference source, XContentType xContentType) {
+    public PutMappingRequest source(BytesReference source, MediaType mediaType) {
         this.source = source;
-        this.xContentType = xContentType;
+        this.mediaType = mediaType;
         return this;
     }
 
@@ -153,7 +155,7 @@ public PutMappingRequest source(BytesReference source, XContentType xContentType
     public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
         if (source != null) {
             try (InputStream stream = source.streamInput()) {
-                builder.rawValue(stream, xContentType);
+                builder.rawValue(stream, mediaType);
             }
         } else {
             builder.startObject().endObject();
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeRequest.java
index 2a22c8d7d19e9..e53bdd99b3cee 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeRequest.java
@@ -37,8 +37,9 @@
 import org.opensearch.client.Validatable;
 import org.opensearch.client.ValidationException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -58,6 +59,7 @@ public class ResizeRequest extends TimedRequest implements Validatable, ToXConte
     private final String targetIndex;
     private Settings settings = Settings.EMPTY;
     private Set<Alias> aliases = new HashSet<>();
+    private ByteSizeValue maxShardSize;
 
     /**
      * Creates a new resize request
@@ -155,6 +157,24 @@ public ActiveShardCount getWaitForActiveShards() {
         return waitForActiveShards;
     }
 
+    /**
+     * Sets the maximum size of a primary shard in the new shrunken index.
+     * This parameter can be used to calculate the lowest factor of the source index's shards number
+     * which satisfies the maximum shard size requirement.
+     *
+     * @param maxShardSize the maximum size of a primary shard in the new shrunken index
+     */
+    public void setMaxShardSize(ByteSizeValue maxShardSize) {
+        this.maxShardSize = maxShardSize;
+    }
+
+    /**
+     * Returns the maximum size of a primary shard in the new shrunken index.
+     */
+    public ByteSizeValue getMaxShardSize() {
+        return maxShardSize;
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject();
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeResponse.java
index cd6346ea81d20..04d690c9922ec 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/ResizeResponse.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.client.core.AcknowledgedResponse;
 import org.opensearch.client.core.ShardsAcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * The response from a {@link ResizeRequest} call
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateRequest.java
index ab894dfcf7fa1..abc095b3ccac9 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateRequest.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.client.TimedRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /**
  * A request to simulate matching a provided index name and an optional new index template against the existing index templates.
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateResponse.java
index a2156a32fa199..d1bc316cc3db4 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/SimulateIndexTemplateResponse.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverRequest.java
index 85f2836db5cba..45211864a3df3 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverRequest.java
@@ -37,10 +37,10 @@
 import org.opensearch.action.admin.indices.rollover.MaxSizeCondition;
 import org.opensearch.client.TimedRequest;
 import org.opensearch.client.indices.CreateIndexRequest;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.HashMap;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverResponse.java
index 0303dba2535e7..b146d4f94e131 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/indices/rollover/RolloverResponse.java
@@ -33,14 +33,14 @@
 package org.opensearch.client.indices.rollover;
 
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Response object for {@link RolloverRequest} API
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/ExecuteSnapshotLifecyclePolicyResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/ExecuteSnapshotLifecyclePolicyResponse.java
index 7b22b83bcf533..48cc41653a8b1 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/ExecuteSnapshotLifecyclePolicyResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/ExecuteSnapshotLifecyclePolicyResponse.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.client.slm;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecyclePolicyResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecyclePolicyResponse.java
index 0ed4ea751b42b..c1329e2bacd59 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecyclePolicyResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecyclePolicyResponse.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.client.slm;
 
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 public class GetSnapshotLifecyclePolicyResponse implements ToXContentObject {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecycleStatsResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecycleStatsResponse.java
index 5feda2ac49b2f..858a9ebe1ff40 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecycleStatsResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/GetSnapshotLifecycleStatsResponse.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.client.slm;
 
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/PutSnapshotLifecyclePolicyRequest.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/PutSnapshotLifecyclePolicyRequest.java
index f6e59c0301b9c..30b271cab45c8 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/PutSnapshotLifecyclePolicyRequest.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/PutSnapshotLifecyclePolicyRequest.java
@@ -33,8 +33,8 @@
 package org.opensearch.client.slm;
 
 import org.opensearch.client.TimedRequest;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotInvocationRecord.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotInvocationRecord.java
index 6d60003302acd..ca2a33df9a850 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotInvocationRecord.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotInvocationRecord.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.client.slm;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicy.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicy.java
index a6e08fc6df018..fd101c575b97a 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicy.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicy.java
@@ -33,12 +33,13 @@
 package org.opensearch.client.slm;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
@@ -168,6 +169,6 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicyMetadata.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicyMetadata.java
index 199805d348fd4..dd44d16f0d65e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicyMetadata.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecyclePolicyMetadata.java
@@ -33,12 +33,13 @@
 package org.opensearch.client.slm;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotId;
 
 import java.io.IOException;
@@ -288,7 +289,7 @@ public boolean equals(Object obj) {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
     }
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecycleStats.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecycleStats.java
index 74d3d21952499..476533d9c91ca 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecycleStats.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotLifecycleStats.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.client.slm;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -187,7 +188,7 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     public static class SnapshotPolicyStats implements ToXContentFragment {
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotRetentionConfiguration.java b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotRetentionConfiguration.java
index 2f2aa778b6958..3165b6bede19d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotRetentionConfiguration.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/slm/SnapshotRetentionConfiguration.java
@@ -33,13 +33,14 @@
 package org.opensearch.client.slm;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -150,6 +151,6 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/CancelTasksResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/CancelTasksResponse.java
index 9319e7aa5d292..1c43f9ec1535e 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/CancelTasksResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/CancelTasksResponse.java
@@ -31,14 +31,14 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * cancel tasks response that contains
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/GetTaskResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/GetTaskResponse.java
index 09aed03f26628..9dfff63712250 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/GetTaskResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/GetTaskResponse.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.tasks.TaskInfo;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class GetTaskResponse {
     private final boolean completed;
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/NodeData.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/NodeData.java
index 5449039e1eea1..4ecdff354c37d 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/NodeData.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/NodeData.java
@@ -31,14 +31,15 @@
 
 package org.opensearch.client.tasks;
 
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
+
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
 
 class NodeData {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/OpenSearchException.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/OpenSearchException.java
index 777da5fc7b685..2f341e5102a08 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/OpenSearchException.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/OpenSearchException.java
@@ -31,8 +31,9 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentParser;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -40,7 +41,7 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * client side counterpart of server side
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskId.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskId.java
index cd036a732957b..c2cf2c826b8bd 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskId.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskId.java
@@ -34,7 +34,7 @@
 import java.util.Objects;
 
 /**
- * client side version of a {@link org.opensearch.tasks.TaskId}
+ * client side version of a {@link org.opensearch.core.tasks.TaskId}
  */
 public class TaskId {
 
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskInfo.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskInfo.java
index de8374b283ea6..75badc4e3dbf2 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskInfo.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskInfo.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -54,9 +54,11 @@ public class TaskInfo {
     private long runningTimeNanos;
     private boolean cancellable;
     private boolean cancelled;
+    private Long cancellationStartTime;
     private TaskId parentTaskId;
     private final Map<String, Object> status = new HashMap<>();
     private final Map<String, String> headers = new HashMap<>();
+    private final Map<String, Object> resourceStats = new HashMap<>();
 
     public TaskInfo(TaskId taskId) {
         this.taskId = taskId;
@@ -126,6 +128,14 @@ void setCancelled(boolean cancelled) {
         this.cancelled = cancelled;
     }
 
+    public Long getCancellationStartTime() {
+        return this.cancellationStartTime;
+    }
+
+    public void setCancellationStartTime(Long cancellationStartTime) {
+        this.cancellationStartTime = cancellationStartTime;
+    }
+
     public TaskId getParentTaskId() {
         return parentTaskId;
     }
@@ -150,6 +160,14 @@ public Map<String, Object> getStatus() {
         return status;
     }
 
+    void setResourceStats(Map<String, Object> resourceStats) {
+        this.resourceStats.putAll(resourceStats);
+    }
+
+    public Map<String, Object> getResourceStats() {
+        return resourceStats;
+    }
+
     private void noOpParse(Object s) {}
 
     public static final ObjectParser.NamedObjectParser<TaskInfo, Void> PARSER;
@@ -170,6 +188,8 @@ private void noOpParse(Object s) {}
         parser.declareBoolean(TaskInfo::setCancelled, new ParseField("cancelled"));
         parser.declareString(TaskInfo::setParentTaskId, new ParseField("parent_task_id"));
         parser.declareObject(TaskInfo::setHeaders, (p, c) -> p.mapStrings(), new ParseField("headers"));
+        parser.declareObject(TaskInfo::setResourceStats, (p, c) -> p.map(), new ParseField("resource_stats"));
+        parser.declareLong(TaskInfo::setCancellationStartTime, new ParseField("cancellation_time_millis"));
         PARSER = (XContentParser p, Void v, String name) -> parser.parse(p, new TaskInfo(new TaskId(name)), null);
     }
 
@@ -188,7 +208,9 @@ && isCancelled() == taskInfo.isCancelled()
             && Objects.equals(getDescription(), taskInfo.getDescription())
             && Objects.equals(getParentTaskId(), taskInfo.getParentTaskId())
             && Objects.equals(status, taskInfo.status)
-            && Objects.equals(getHeaders(), taskInfo.getHeaders());
+            && Objects.equals(getHeaders(), taskInfo.getHeaders())
+            && Objects.equals(getResourceStats(), taskInfo.getResourceStats())
+            && Objects.equals(getCancellationStartTime(), taskInfo.cancellationStartTime);
     }
 
     @Override
@@ -204,7 +226,9 @@ public int hashCode() {
             isCancelled(),
             getParentTaskId(),
             status,
-            getHeaders()
+            getHeaders(),
+            getResourceStats(),
+            getCancellationStartTime()
         );
     }
 
@@ -236,6 +260,10 @@ public String toString() {
             + status
             + ", headers="
             + headers
+            + ", resource_stats="
+            + resourceStats
+            + ", cancellationStartTime="
+            + cancellationStartTime
             + '}';
     }
 }
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskOperationFailure.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskOperationFailure.java
index f173da9daa8fc..c4395f5cb81d1 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskOperationFailure.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskOperationFailure.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * client side counterpart of server side
diff --git a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskSubmissionResponse.java b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskSubmissionResponse.java
index 6077455224b7d..7ec3e974de468 100644
--- a/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskSubmissionResponse.java
+++ b/client/rest-high-level/src/main/java/org/opensearch/client/tasks/TaskSubmissionResponse.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
diff --git a/client/rest-high-level/src/main/resources/forbidden/rest-high-level-signatures.txt b/client/rest-high-level/src/main/resources/forbidden/rest-high-level-signatures.txt
index 68dc509e5ff27..bee105f05e6b4 100644
--- a/client/rest-high-level/src/main/resources/forbidden/rest-high-level-signatures.txt
+++ b/client/rest-high-level/src/main/resources/forbidden/rest-high-level-signatures.txt
@@ -14,7 +14,7 @@
 # either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 
-@defaultMessage Use Request#createContentType(XContentType) to be sure to pass the right MIME type
+@defaultMessage Use Request#createContentType(MediaType) to be sure to pass the right MIME type
 org.apache.http.entity.ContentType#create(java.lang.String)
 org.apache.http.entity.ContentType#create(java.lang.String,java.lang.String)
 org.apache.http.entity.ContentType#create(java.lang.String,java.nio.charset.Charset)
@@ -23,7 +23,7 @@ org.apache.http.entity.ContentType#create(java.lang.String,org.apache.http.NameV
 @defaultMessage ES's logging infrastructure uses log4j2 which we don't want to force on high level rest client users
 org.opensearch.common.logging.DeprecationLogger
 org.opensearch.common.logging.LogConfigurator
-org.opensearch.common.logging.LoggerMessageFormat
+org.opensearch.core.common.logging.LoggerMessageFormat
 org.opensearch.common.logging.Loggers
 org.opensearch.common.logging.NodeNamePatternConverter
 org.opensearch.common.logging.PrefixLogger
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/AbstractRequestTestCase.java b/client/rest-high-level/src/test/java/org/opensearch/client/AbstractRequestTestCase.java
index e63375c34f97e..49bcb61b2dc3d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/AbstractRequestTestCase.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/AbstractRequestTestCase.java
@@ -31,14 +31,13 @@
 
 package org.opensearch.client;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -60,7 +59,7 @@ public final void testFromXContent() throws IOException {
         final XContentType xContentType = randomFrom(XContentType.values());
         final BytesReference bytes = toShuffledXContent(clientTestInstance, xContentType, ToXContent.EMPTY_PARAMS, randomBoolean());
 
-        final XContent xContent = XContentFactory.xContent(xContentType);
+        final XContent xContent = xContentType.xContent();
         final XContentParser parser = xContent.createParser(xContentRegistry(), LoggingDeprecationHandler.INSTANCE, bytes.streamInput());
         final S serverInstance = doParseToServerInstance(parser);
         assertInstances(serverInstance, clientTestInstance);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/AbstractResponseTestCase.java b/client/rest-high-level/src/test/java/org/opensearch/client/AbstractResponseTestCase.java
index 95188ec0f8e96..27704b01560c4 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/AbstractResponseTestCase.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/AbstractResponseTestCase.java
@@ -31,22 +31,16 @@
 
 package org.opensearch.client;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.Map;
-import java.util.Set;
 
 /**
  * Base class for HLRC response parsing tests.
@@ -64,7 +58,7 @@ public final void testFromXContent() throws IOException {
         final S serverTestInstance = createServerTestInstance(xContentType);
         final BytesReference bytes = toShuffledXContent(serverTestInstance, xContentType, getParams(), randomBoolean());
 
-        final XContent xContent = XContentFactory.xContent(xContentType);
+        final XContent xContent = xContentType.xContent();
         final XContentParser parser = xContent.createParser(
             NamedXContentRegistry.EMPTY,
             LoggingDeprecationHandler.INSTANCE,
@@ -103,17 +97,4 @@ public final void testFromXContent() throws IOException {
     protected ToXContent.Params getParams() {
         return ToXContent.EMPTY_PARAMS;
     }
-
-    protected static <T> void assertMapEquals(ImmutableOpenMap<String, T> expected, Map<String, T> actual) {
-        Set<String> expectedKeys = new HashSet<>();
-        Iterator<String> keysIt = expected.keysIt();
-        while (keysIt.hasNext()) {
-            expectedKeys.add(keysIt.next());
-        }
-
-        assertEquals(expectedKeys, actual.keySet());
-        for (String key : expectedKeys) {
-            assertEquals(expected.get(key), actual.get(key));
-        }
-    }
 }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorIT.java
index cc9abdccf4c9f..1d70778398e2e 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorIT.java
@@ -33,6 +33,7 @@
 package org.opensearch.client;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkProcessor;
 import org.opensearch.action.bulk.BulkRequest;
@@ -42,13 +43,12 @@
 import org.opensearch.action.get.MultiGetResponse;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
 import org.hamcrest.Matcher;
 
@@ -278,12 +278,12 @@ public void testBulkProcessorConcurrentRequestsReadOnlyIndex() throws Exception
                 // let's make sure we get at least 1 item in the MultiGetRequest regardless of the randomising roulette
                 if (randomBoolean() || multiGetRequest.getItems().size() == 0) {
                     testDocs++;
-                    processor.add(new IndexRequest("test").id(Integer.toString(testDocs)).source(XContentType.JSON, "field", "value"));
+                    processor.add(new IndexRequest("test").id(Integer.toString(testDocs)).source(MediaTypeRegistry.JSON, "field", "value"));
                     multiGetRequest.add("test", Integer.toString(testDocs));
                 } else {
                     testReadOnlyDocs++;
                     processor.add(
-                        new IndexRequest("test-ro").id(Integer.toString(testReadOnlyDocs)).source(XContentType.JSON, "field", "value")
+                        new IndexRequest("test-ro").id(Integer.toString(testReadOnlyDocs)).source(MediaTypeRegistry.JSON, "field", "value")
                     );
                 }
             }
@@ -334,9 +334,9 @@ public void testGlobalParametersAndSingleRequest() throws Exception {
 
 
             processor.add(new IndexRequest() // <1>
-                .source(XContentType.JSON, "user", "some user"));
+                .source(MediaTypeRegistry.JSON, "user", "some user"));
             processor.add(new IndexRequest("blogs").id("1") // <2>
-                .source(XContentType.JSON, "title", "some title"));
+                .source(MediaTypeRegistry.JSON, "title", "some title"));
         }
         // end::bulk-processor-mix-parameters
         latch.await();
@@ -400,11 +400,11 @@ private MultiGetRequest indexDocs(BulkProcessor processor, int numDocs, String l
             if (randomBoolean()) {
                 processor.add(
                     new IndexRequest(localIndex).id(Integer.toString(i))
-                        .source(XContentType.JSON, "field", randomRealisticUnicodeOfLengthBetween(1, 30))
+                        .source(MediaTypeRegistry.JSON, "field", randomRealisticUnicodeOfLengthBetween(1, 30))
                 );
             } else {
                 BytesArray data = bytesBulkRequest(localIndex, i);
-                processor.add(data, globalIndex, globalPipeline, XContentType.JSON);
+                processor.add(data, globalIndex, globalPipeline, MediaTypeRegistry.JSON);
             }
             multiGetRequest.add(localIndex, Integer.toString(i));
         }
@@ -423,7 +423,7 @@ private static BytesArray bytesBulkRequest(String localIndex, int id) throws IOE
 
         XContentBuilder source = jsonBuilder().startObject().field("field", randomRealisticUnicodeOfLengthBetween(1, 30)).endObject();
 
-        String request = Strings.toString(action) + "\n" + Strings.toString(source) + "\n";
+        String request = action + "\n" + source + "\n";
         return new BytesArray(request);
     }
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorRetryIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorRetryIT.java
index 0744fe4e6db3e..b7f6328b3c88e 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorRetryIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/BulkProcessorRetryIT.java
@@ -40,8 +40,8 @@
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.transport.RemoteTransportException;
 
 import java.util.Collections;
@@ -170,7 +170,7 @@ private static MultiGetRequest indexDocs(BulkProcessor processor, int numDocs) {
         for (int i = 1; i <= numDocs; i++) {
             processor.add(
                 new IndexRequest(INDEX_NAME).id(Integer.toString(i))
-                    .source(XContentType.JSON, "field", randomRealisticUnicodeOfCodepointLengthBetween(1, 30))
+                    .source(MediaTypeRegistry.JSON, "field", randomRealisticUnicodeOfCodepointLengthBetween(1, 30))
             );
             multiGetRequest.add(INDEX_NAME, Integer.toString(i));
         }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/BulkRequestWithGlobalParametersIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/BulkRequestWithGlobalParametersIT.java
index 35fc9d88e316c..d392aa842fb35 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/BulkRequestWithGlobalParametersIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/BulkRequestWithGlobalParametersIT.java
@@ -36,7 +36,7 @@
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.search.SearchHit;
 
 import java.io.IOException;
@@ -59,8 +59,8 @@ public void testGlobalPipelineOnBulkRequest() throws IOException {
         createFieldAddingPipleine("xyz", "fieldNameXYZ", "valueXYZ");
 
         BulkRequest request = new BulkRequest();
-        request.add(new IndexRequest("test").id("1").source(XContentType.JSON, "field", "bulk1"));
-        request.add(new IndexRequest("test").id("2").source(XContentType.JSON, "field", "bulk2"));
+        request.add(new IndexRequest("test").id("1").source(MediaTypeRegistry.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("test").id("2").source(MediaTypeRegistry.JSON, "field", "bulk2"));
         request.pipeline("xyz");
 
         bulk(request);
@@ -76,8 +76,8 @@ public void testPipelineOnRequestOverridesGlobalPipeline() throws IOException {
 
         BulkRequest request = new BulkRequest();
         request.pipeline("globalId");
-        request.add(new IndexRequest("test").id("1").source(XContentType.JSON, "field", "bulk1").setPipeline("perIndexId"));
-        request.add(new IndexRequest("test").id("2").source(XContentType.JSON, "field", "bulk2").setPipeline("perIndexId"));
+        request.add(new IndexRequest("test").id("1").source(MediaTypeRegistry.JSON, "field", "bulk1").setPipeline("perIndexId"));
+        request.add(new IndexRequest("test").id("2").source(MediaTypeRegistry.JSON, "field", "bulk2").setPipeline("perIndexId"));
 
         bulk(request);
 
@@ -96,11 +96,11 @@ public void testMixPipelineOnRequestAndGlobal() throws IOException {
         request.pipeline("globalId");
 
         request.add(new IndexRequest("test").id("1")
-            .source(XContentType.JSON, "field", "bulk1")
+            .source(MediaTypeRegistry.JSON, "field", "bulk1")
             .setPipeline("perIndexId")); // <1>
 
         request.add(new IndexRequest("test").id("2")
-            .source(XContentType.JSON, "field", "bulk2")); // <2>
+            .source(MediaTypeRegistry.JSON, "field", "bulk2")); // <2>
         // end::bulk-request-mix-pipeline
         bulk(request);
 
@@ -116,8 +116,8 @@ public void testMixPipelineOnRequestAndGlobal() throws IOException {
 
     public void testGlobalIndex() throws IOException {
         BulkRequest request = new BulkRequest("global_index");
-        request.add(new IndexRequest().id("1").source(XContentType.JSON, "field", "bulk1"));
-        request.add(new IndexRequest().id("2").source(XContentType.JSON, "field", "bulk2"));
+        request.add(new IndexRequest().id("1").source(MediaTypeRegistry.JSON, "field", "bulk1"));
+        request.add(new IndexRequest().id("2").source(MediaTypeRegistry.JSON, "field", "bulk2"));
 
         bulk(request);
 
@@ -128,10 +128,10 @@ public void testGlobalIndex() throws IOException {
     @SuppressWarnings("unchecked")
     public void testIndexGlobalAndPerRequest() throws IOException {
         BulkRequest request = new BulkRequest("global_index");
-        request.add(new IndexRequest("local_index").id("1").source(XContentType.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("local_index").id("1").source(MediaTypeRegistry.JSON, "field", "bulk1"));
         request.add(
             new IndexRequest().id("2") // will take global index
-                .source(XContentType.JSON, "field", "bulk2")
+                .source(MediaTypeRegistry.JSON, "field", "bulk2")
         );
 
         bulk(request);
@@ -143,8 +143,8 @@ public void testIndexGlobalAndPerRequest() throws IOException {
     public void testGlobalRouting() throws IOException {
         createIndexWithMultipleShards("index");
         BulkRequest request = new BulkRequest((String) null);
-        request.add(new IndexRequest("index").id("1").source(XContentType.JSON, "field", "bulk1"));
-        request.add(new IndexRequest("index").id("2").source(XContentType.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("index").id("1").source(MediaTypeRegistry.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("index").id("2").source(MediaTypeRegistry.JSON, "field", "bulk1"));
         request.routing("1");
         bulk(request);
 
@@ -158,8 +158,8 @@ public void testGlobalRouting() throws IOException {
     public void testMixLocalAndGlobalRouting() throws IOException {
         BulkRequest request = new BulkRequest((String) null);
         request.routing("globalRouting");
-        request.add(new IndexRequest("index").id("1").source(XContentType.JSON, "field", "bulk1"));
-        request.add(new IndexRequest("index").id("2").routing("localRouting").source(XContentType.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("index").id("1").source(MediaTypeRegistry.JSON, "field", "bulk1"));
+        request.add(new IndexRequest("index").id("2").routing("localRouting").source(MediaTypeRegistry.JSON, "field", "bulk1"));
 
         bulk(request);
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/ClusterClientIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/ClusterClientIT.java
index 71b869fb59e7b..66e8d8c7f5c04 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/ClusterClientIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/ClusterClientIT.java
@@ -60,12 +60,12 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.transport.RemoteClusterService;
 import org.opensearch.transport.SniffConnectionStrategy;
 
@@ -124,7 +124,7 @@ public void testClusterPutSettings() throws IOException {
 
         ClusterUpdateSettingsRequest resetRequest = new ClusterUpdateSettingsRequest();
         resetRequest.transientSettings(Settings.builder().putNull(transientSettingKey));
-        resetRequest.persistentSettings("{\"" + persistentSettingKey + "\": null }", XContentType.JSON);
+        resetRequest.persistentSettings("{\"" + persistentSettingKey + "\": null }", MediaTypeRegistry.JSON);
 
         ClusterUpdateSettingsResponse resetResponse = execute(
             resetRequest,
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/ClusterRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/ClusterRequestConvertersTests.java
index 2af164a51dbab..da9de98cad141 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/ClusterRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/ClusterRequestConvertersTests.java
@@ -42,7 +42,7 @@
 import org.opensearch.client.cluster.RemoteInfoRequest;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.CoreMatchers;
 import org.junit.Assert;
@@ -91,7 +91,7 @@ public void testClusterHealth() {
         RequestConvertersTests.setRandomLocal(healthRequest::local, expectedParams);
         String timeoutType = OpenSearchTestCase.randomFrom("timeout", "masterTimeout", "both", "none");
         String timeout = OpenSearchTestCase.randomTimeValue();
-        String masterTimeout = OpenSearchTestCase.randomTimeValue();
+        String clusterManagerTimeout = OpenSearchTestCase.randomTimeValue();
         switch (timeoutType) {
             case "timeout":
                 healthRequest.timeout(timeout);
@@ -101,13 +101,13 @@ public void testClusterHealth() {
                 break;
             case "masterTimeout":
                 expectedParams.put("timeout", "30s");
-                healthRequest.masterNodeTimeout(masterTimeout);
-                expectedParams.put("master_timeout", masterTimeout);
+                healthRequest.clusterManagerNodeTimeout(clusterManagerTimeout);
+                expectedParams.put("master_timeout", clusterManagerTimeout);
                 break;
             case "both":
                 healthRequest.timeout(timeout);
                 expectedParams.put("timeout", timeout);
-                healthRequest.masterNodeTimeout(timeout);
+                healthRequest.clusterManagerNodeTimeout(timeout);
                 expectedParams.put("master_timeout", timeout);
                 break;
             case "none":
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/CrudIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/CrudIT.java
index 999c2a0e7643b..da9f790215669 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/CrudIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/CrudIT.java
@@ -58,17 +58,19 @@
 import org.opensearch.client.core.TermVectorsRequest;
 import org.opensearch.client.core.TermVectorsResponse;
 import org.opensearch.client.indices.GetIndexRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.get.GetResult;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -202,7 +204,7 @@ public void testExists() throws IOException {
             assertFalse(execute(getRequest, highLevelClient()::exists, highLevelClient()::existsAsync));
         }
         IndexRequest index = new IndexRequest("index").id("id");
-        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", XContentType.JSON);
+        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", MediaTypeRegistry.JSON);
         index.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         highLevelClient().index(index, RequestOptions.DEFAULT);
         {
@@ -227,7 +229,7 @@ public void testDeprecatedSourceExists() throws IOException {
             assertFalse(execute(getRequest, highLevelClient()::existsSource, highLevelClient()::existsSourceAsync));
         }
         IndexRequest index = new IndexRequest("index").id("id");
-        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", XContentType.JSON);
+        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", MediaTypeRegistry.JSON);
         index.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         highLevelClient().index(index, RequestOptions.DEFAULT);
         {
@@ -250,7 +252,7 @@ public void testSourceExists() throws IOException {
             assertFalse(execute(getRequest, highLevelClient()::existsSource, highLevelClient()::existsSourceAsync));
         }
         IndexRequest index = new IndexRequest("index").id("id");
-        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", XContentType.JSON);
+        index.source("{\"field1\":\"value1\",\"field2\":\"value2\"}", MediaTypeRegistry.JSON);
         index.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         highLevelClient().index(index, RequestOptions.DEFAULT);
         {
@@ -274,9 +276,9 @@ public void testSourceDoesNotExist() throws IOException {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(noSourceIndex).id("1").source(Collections.singletonMap("foo", 1), XContentType.JSON)
+                        new IndexRequest(noSourceIndex).id("1").source(Collections.singletonMap("foo", 1), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(noSourceIndex).id("2").source(Collections.singletonMap("foo", 2), XContentType.JSON))
+                        .add(new IndexRequest(noSourceIndex).id("2").source(Collections.singletonMap("foo", 2), MediaTypeRegistry.JSON))
                         .setRefreshPolicy(RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
@@ -306,7 +308,7 @@ public void testGet() throws IOException {
         }
         IndexRequest index = new IndexRequest("index").id("id");
         String document = "{\"field1\":\"value1\",\"field2\":\"value2\"}";
-        index.source(document, XContentType.JSON);
+        index.source(document, MediaTypeRegistry.JSON);
         index.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         highLevelClient().index(index, RequestOptions.DEFAULT);
         {
@@ -406,10 +408,10 @@ public void testMultiGet() throws IOException {
         BulkRequest bulk = new BulkRequest();
         bulk.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         IndexRequest index = new IndexRequest("index").id("id1");
-        index.source("{\"field\":\"value1\"}", XContentType.JSON);
+        index.source("{\"field\":\"value1\"}", MediaTypeRegistry.JSON);
         bulk.add(index);
         index = new IndexRequest("index").id("id2");
-        index.source("{\"field\":\"value2\"}", XContentType.JSON);
+        index.source("{\"field\":\"value2\"}", MediaTypeRegistry.JSON);
         bulk.add(index);
         highLevelClient().bulk(bulk, RequestOptions.DEFAULT);
         {
@@ -436,8 +438,8 @@ public void testMultiGet() throws IOException {
     public void testMultiGetWithIds() throws IOException {
         BulkRequest bulk = new BulkRequest();
         bulk.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
-        bulk.add(new IndexRequest("index").id("id1").source("{\"field\":\"value1\"}", XContentType.JSON));
-        bulk.add(new IndexRequest("index").id("id2").source("{\"field\":\"value2\"}", XContentType.JSON));
+        bulk.add(new IndexRequest("index").id("id1").source("{\"field\":\"value1\"}", MediaTypeRegistry.JSON));
+        bulk.add(new IndexRequest("index").id("id2").source("{\"field\":\"value2\"}", MediaTypeRegistry.JSON));
 
         MultiGetRequest multiGetRequest = new MultiGetRequest();
         multiGetRequest.add("index", "id1");
@@ -457,7 +459,7 @@ public void testGetSource() throws IOException {
         }
         IndexRequest index = new IndexRequest("index").id("id");
         String document = "{\"field1\":\"value1\",\"field2\":\"value2\"}";
-        index.source(document, XContentType.JSON);
+        index.source(document, MediaTypeRegistry.JSON);
         index.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         highLevelClient().index(index, RequestOptions.DEFAULT);
         {
@@ -628,10 +630,9 @@ public void testIndex() throws IOException {
             assertEquals("index", indexResponse.getIndex());
             assertEquals("with_create_op_type", indexResponse.getId());
 
-            OpenSearchStatusException exception = expectThrows(
-                OpenSearchStatusException.class,
-                () -> { execute(indexRequest, highLevelClient()::index, highLevelClient()::indexAsync); }
-            );
+            OpenSearchStatusException exception = expectThrows(OpenSearchStatusException.class, () -> {
+                execute(indexRequest, highLevelClient()::index, highLevelClient()::indexAsync);
+            });
 
             assertEquals(RestStatus.CONFLICT, exception.status());
             assertEquals(
@@ -816,7 +817,7 @@ public void testUpdate() throws IOException {
         {
             IllegalStateException exception = expectThrows(IllegalStateException.class, () -> {
                 UpdateRequest updateRequest = new UpdateRequest("index", "id");
-                updateRequest.doc(new IndexRequest().source(Collections.singletonMap("field", "doc"), XContentType.JSON));
+                updateRequest.doc(new IndexRequest().source(Collections.singletonMap("field", "doc"), MediaTypeRegistry.JSON));
                 updateRequest.upsert(new IndexRequest().source(Collections.singletonMap("field", "upsert"), XContentType.YAML));
                 execute(updateRequest, highLevelClient()::update, highLevelClient()::updateAsync);
             });
@@ -828,7 +829,7 @@ public void testUpdate() throws IOException {
         {
             OpenSearchException exception = expectThrows(OpenSearchException.class, () -> {
                 UpdateRequest updateRequest = new UpdateRequest("index", "require_alias").setRequireAlias(true);
-                updateRequest.doc(new IndexRequest().source(Collections.singletonMap("field", "doc"), XContentType.JSON));
+                updateRequest.doc(new IndexRequest().source(Collections.singletonMap("field", "doc"), MediaTypeRegistry.JSON));
                 execute(updateRequest, highLevelClient()::update, highLevelClient()::updateAsync);
             });
             assertEquals(RestStatus.NOT_FOUND, exception.status());
@@ -843,7 +844,7 @@ public void testBulk() throws IOException {
         int nbItems = randomIntBetween(10, 100);
         boolean[] errors = new boolean[nbItems];
 
-        XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+        MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
 
         BulkRequest bulkRequest = new BulkRequest();
         for (int i = 0; i < nbItems; i++) {
@@ -864,10 +865,10 @@ public void testBulk() throws IOException {
 
             } else {
                 BytesReference source = BytesReference.bytes(
-                    XContentBuilder.builder(xContentType.xContent()).startObject().field("id", i).endObject()
+                    XContentBuilder.builder(mediaType.xContent()).startObject().field("id", i).endObject()
                 );
                 if (opType == DocWriteRequest.OpType.INDEX) {
-                    IndexRequest indexRequest = new IndexRequest("index").id(id).source(source, xContentType);
+                    IndexRequest indexRequest = new IndexRequest("index").id(id).source(source, mediaType);
                     if (erroneous) {
                         indexRequest.setIfSeqNo(12L);
                         indexRequest.setIfPrimaryTerm(12L);
@@ -875,14 +876,14 @@ public void testBulk() throws IOException {
                     bulkRequest.add(indexRequest);
 
                 } else if (opType == DocWriteRequest.OpType.CREATE) {
-                    IndexRequest createRequest = new IndexRequest("index").id(id).source(source, xContentType).create(true);
+                    IndexRequest createRequest = new IndexRequest("index").id(id).source(source, mediaType).create(true);
                     if (erroneous) {
                         assertEquals(RestStatus.CREATED, highLevelClient().index(createRequest, RequestOptions.DEFAULT).status());
                     }
                     bulkRequest.add(createRequest);
 
                 } else if (opType == DocWriteRequest.OpType.UPDATE) {
-                    UpdateRequest updateRequest = new UpdateRequest("index", id).doc(new IndexRequest().source(source, xContentType));
+                    UpdateRequest updateRequest = new UpdateRequest("index", id).doc(new IndexRequest().source(source, mediaType));
                     if (erroneous == false) {
                         assertEquals(
                             RestStatus.CREATED,
@@ -906,7 +907,7 @@ public void testBulkProcessorIntegration() throws IOException {
         int nbItems = randomIntBetween(10, 100);
         boolean[] errors = new boolean[nbItems];
 
-        XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+        MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
 
         AtomicReference<BulkResponse> responseRef = new AtomicReference<>();
         AtomicReference<BulkRequest> requestRef = new AtomicReference<>();
@@ -954,7 +955,7 @@ public void afterBulk(long executionId, BulkRequest request, Throwable failure)
 
                 } else {
                     if (opType == DocWriteRequest.OpType.INDEX) {
-                        IndexRequest indexRequest = new IndexRequest("index").id(id).source(xContentType, "id", i);
+                        IndexRequest indexRequest = new IndexRequest("index").id(id).source(mediaType, "id", i);
                         if (erroneous) {
                             indexRequest.setIfSeqNo(12L);
                             indexRequest.setIfPrimaryTerm(12L);
@@ -962,14 +963,14 @@ public void afterBulk(long executionId, BulkRequest request, Throwable failure)
                         processor.add(indexRequest);
 
                     } else if (opType == DocWriteRequest.OpType.CREATE) {
-                        IndexRequest createRequest = new IndexRequest("index").id(id).source(xContentType, "id", i).create(true);
+                        IndexRequest createRequest = new IndexRequest("index").id(id).source(mediaType, "id", i).create(true);
                         if (erroneous) {
                             assertEquals(RestStatus.CREATED, highLevelClient().index(createRequest, RequestOptions.DEFAULT).status());
                         }
                         processor.add(createRequest);
 
                     } else if (opType == DocWriteRequest.OpType.UPDATE) {
-                        UpdateRequest updateRequest = new UpdateRequest("index", id).doc(new IndexRequest().source(xContentType, "id", i));
+                        UpdateRequest updateRequest = new UpdateRequest("index", id).doc(new IndexRequest().source(mediaType, "id", i));
                         if (erroneous == false) {
                             assertEquals(
                                 RestStatus.CREATED,
@@ -1107,9 +1108,12 @@ public void testTermvectors() throws IOException {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("field", "value1"), XContentType.JSON)
+                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("field", "value1"), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("field", "value2"), XContentType.JSON))
+                        .add(
+                            new IndexRequest(sourceIndex).id("2")
+                                .source(Collections.singletonMap("field", "value2"), MediaTypeRegistry.JSON)
+                        )
                         .setRefreshPolicy(RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
@@ -1202,8 +1206,8 @@ public void testMultiTermvectors() throws IOException {
             assertEquals(
                 RestStatus.OK,
                 highLevelClient().bulk(
-                    new BulkRequest().add(new IndexRequest(sourceIndex).id("1").source(doc1, XContentType.JSON))
-                        .add(new IndexRequest(sourceIndex).id("2").source(doc2, XContentType.JSON))
+                    new BulkRequest().add(new IndexRequest(sourceIndex).id("1").source(doc1, MediaTypeRegistry.JSON))
+                        .add(new IndexRequest(sourceIndex).id("2").source(doc2, MediaTypeRegistry.JSON))
                         .setRefreshPolicy(RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/CustomRestHighLevelClientTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/CustomRestHighLevelClientTests.java
index 1d94f190c611c..5204108a1d2a6 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/CustomRestHighLevelClientTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/CustomRestHighLevelClientTests.java
@@ -44,14 +44,14 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Build;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.main.MainRequest;
 import org.opensearch.action.main.MainResponse;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
@@ -175,7 +175,7 @@ private Response mockPerformRequest(Request request) throws IOException {
         when(mockResponse.getStatusLine()).thenReturn(new BasicStatusLine(protocol, 200, "OK"));
 
         MainResponse response = new MainResponse(httpHeader.getValue(), Version.CURRENT, ClusterName.DEFAULT, "_na", Build.CURRENT);
-        BytesRef bytesRef = XContentHelper.toXContent(response, XContentType.JSON, false).toBytesRef();
+        BytesRef bytesRef = XContentHelper.toXContent(response, MediaTypeRegistry.JSON, false).toBytesRef();
         when(mockResponse.getEntity()).thenReturn(new NByteArrayEntity(bytesRef.bytes, ContentType.APPLICATION_JSON));
 
         RequestLine requestLine = new BasicRequestLine(HttpGet.METHOD_NAME, ENDPOINT, protocol);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/GetAliasesResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/GetAliasesResponseTests.java
index 67b1c0bc3b9a9..245a720dc9825 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/GetAliasesResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/GetAliasesResponseTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.client;
 
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/IndicesClientIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/IndicesClientIT.java
index f9c8851f8839e..649e921b54cbe 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/IndicesClientIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/IndicesClientIT.java
@@ -107,24 +107,24 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.metadata.Template;
-import org.opensearch.common.Strings;
 import org.opensearch.common.ValidationException;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -134,6 +134,10 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.common.xcontent.support.XContentMapValues.extractRawValues;
+import static org.opensearch.common.xcontent.support.XContentMapValues.extractValue;
 import static org.hamcrest.CoreMatchers.hasItem;
 import static org.hamcrest.Matchers.arrayContainingInAnyOrder;
 import static org.hamcrest.Matchers.contains;
@@ -149,10 +153,6 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.startsWith;
 import static org.hamcrest.core.IsInstanceOf.instanceOf;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
-import static org.opensearch.common.xcontent.support.XContentMapValues.extractRawValues;
-import static org.opensearch.common.xcontent.support.XContentMapValues.extractValue;
 
 public class IndicesClientIT extends OpenSearchRestHighLevelClientTestCase {
 
@@ -1074,7 +1074,7 @@ public void testRollover() throws IOException {
         }
         {
             String mappings = "{\"properties\":{\"field2\":{\"type\":\"keyword\"}}}";
-            rolloverRequest.getCreateIndexRequest().mapping(mappings, XContentType.JSON);
+            rolloverRequest.getCreateIndexRequest().mapping(mappings, MediaTypeRegistry.JSON);
             rolloverRequest.dryRun(false);
             rolloverRequest.addMaxIndexSizeCondition(new ByteSizeValue(1, ByteSizeUnit.MB));
             RolloverResponse rolloverResponse = execute(
@@ -1490,7 +1490,7 @@ public void testPutTemplate() throws Exception {
             .order(10)
             .create(randomBoolean())
             .settings(Settings.builder().put("number_of_shards", "3").put("number_of_replicas", "0"))
-            .mapping("{ \"properties\": { \"host_name\": { \"type\": \"keyword\" } } }", XContentType.JSON)
+            .mapping("{ \"properties\": { \"host_name\": { \"type\": \"keyword\" } } }", MediaTypeRegistry.JSON)
             .alias(new Alias("alias-1").indexRouting("abc"))
             .alias(new Alias("alias-1").indexRouting("abc"))
             .alias(new Alias("{index}-write").searchRouting("xyz"));
@@ -1559,7 +1559,7 @@ public void testPutTemplateWithTypesUsingUntypedAPI() throws Exception {
                     + "    }"
                     + "  }"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .alias(new Alias("alias-1").indexRouting("abc"))
             .alias(new Alias("{index}-write").searchRouting("xyz"));
@@ -1665,7 +1665,7 @@ public void testCRUDIndexTemplate() throws Exception {
             equalTo(true)
         );
         PutIndexTemplateRequest putTemplate2 = new PutIndexTemplateRequest("template-2").patterns(Arrays.asList("pattern-2", "name-2"))
-            .mapping("{\"properties\": { \"name\": { \"type\": \"text\" }}}", XContentType.JSON)
+            .mapping("{\"properties\": { \"name\": { \"type\": \"text\" }}}", MediaTypeRegistry.JSON)
             .settings(Settings.builder().put("number_of_shards", "2").put("number_of_replicas", "0"));
         assertThat(
             execute(putTemplate2, client.indices()::putTemplate, client.indices()::putTemplateAsync).isAcknowledged(),
@@ -2032,8 +2032,8 @@ public void testSimulateIndexTemplate() throws Exception {
         Settings settings = Settings.builder().put("index.number_of_shards", 1).build();
         CompressedXContent mappings = new CompressedXContent("{\"properties\":{\"host_name\":{\"type\":\"keyword\"}}}");
         AliasMetadata alias = AliasMetadata.builder("alias").writeIndex(true).build();
-        Template template = new Template(settings, mappings, org.opensearch.common.collect.Map.of("alias", alias));
-        List<String> pattern = org.opensearch.common.collect.List.of("pattern");
+        Template template = new Template(settings, mappings, Map.of("alias", alias));
+        List<String> pattern = List.of("pattern");
         ComposableIndexTemplate indexTemplate = new ComposableIndexTemplate(
             pattern,
             template,
@@ -2058,7 +2058,7 @@ public void testSimulateIndexTemplate() throws Exception {
         AliasMetadata simulationAlias = AliasMetadata.builder("simulation-alias").writeIndex(true).build();
         ComposableIndexTemplate simulationTemplate = new ComposableIndexTemplate(
             pattern,
-            new Template(null, null, org.opensearch.common.collect.Map.of("simulation-alias", simulationAlias)),
+            new Template(null, null, Map.of("simulation-alias", simulationAlias)),
             Collections.emptyList(),
             2L,
             1L,
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/IndicesRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/IndicesRequestConvertersTests.java
index f853378e789fa..9adef6981788e 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/IndicesRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/IndicesRequestConvertersTests.java
@@ -72,11 +72,12 @@
 import org.opensearch.client.indices.ResizeRequest;
 import org.opensearch.client.indices.rollover.RolloverRequest;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Assert;
 
@@ -595,6 +596,10 @@ public void testClearCache() {
             clearIndicesCacheRequest.fields(RequestConvertersTests.randomIndicesNames(1, 5));
             expectedParams.put("fields", String.join(",", clearIndicesCacheRequest.fields()));
         }
+        if (OpenSearchTestCase.randomBoolean()) {
+            clearIndicesCacheRequest.fileCache(OpenSearchTestCase.randomBoolean());
+        }
+        expectedParams.put("file", Boolean.toString(clearIndicesCacheRequest.fileCache()));
 
         Request request = IndicesRequestConverters.clearCache(clearIndicesCacheRequest);
         StringJoiner endpoint = new StringJoiner("/", "/", "");
@@ -701,6 +706,8 @@ private void resizeTest(ResizeType resizeType, CheckedFunction<ResizeRequest, Re
         RequestConvertersTests.setRandomWaitForActiveShards(resizeRequest::setWaitForActiveShards, expectedParams);
         if (resizeType == ResizeType.SPLIT) {
             resizeRequest.setSettings(Settings.builder().put("index.number_of_shards", 2).build());
+        } else if (resizeType == ResizeType.SHRINK) {
+            resizeRequest.setMaxShardSize(new ByteSizeValue(randomIntBetween(1, 1000)));
         }
 
         Request request = function.apply(resizeRequest);
@@ -851,7 +858,7 @@ public void testPutTemplateRequest() throws Exception {
                     + "\" : { \"type\" : \""
                     + OpenSearchTestCase.randomFrom("text", "keyword")
                     + "\" }}}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             );
         }
         if (OpenSearchTestCase.randomBoolean()) {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/IngestClientIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/IngestClientIT.java
index 78a3202f35892..33bff06a83065 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/IngestClientIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/IngestClientIT.java
@@ -42,9 +42,9 @@
 import org.opensearch.action.ingest.SimulatePipelineRequest;
 import org.opensearch.action.ingest.SimulatePipelineResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.PipelineConfiguration;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/IngestRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/IngestRequestConvertersTests.java
index 0d95b3e7fddc0..5bd144c152d26 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/IngestRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/IngestRequestConvertersTests.java
@@ -41,8 +41,8 @@
 import org.opensearch.action.ingest.PutPipelineRequest;
 import org.opensearch.action.ingest.SimulatePipelineRequest;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Assert;
 
@@ -59,7 +59,7 @@ public void testPutPipeline() throws IOException {
         PutPipelineRequest request = new PutPipelineRequest(
             "some_pipeline_id",
             new BytesArray("{}".getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         Map<String, String> expectedParams = new HashMap<>();
         RequestConvertersTests.setRandomMasterTimeout(request, expectedParams);
@@ -121,7 +121,6 @@ public void testSimulatePipeline() throws IOException {
             + "  \"docs\": ["
             + "    {"
             + "      \"_index\": \"index\","
-            + "      \"_type\": \"_doc\","
             + "      \"_id\": \"id\","
             + "      \"_source\": {"
             + "        \"foo\": \"rab\""
@@ -131,7 +130,7 @@ public void testSimulatePipeline() throws IOException {
             + "}";
         SimulatePipelineRequest request = new SimulatePipelineRequest(
             new BytesArray(json.getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         request.setId(pipelineId);
         request.setVerbose(verbose);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/NodesResponseHeaderTestUtils.java b/client/rest-high-level/src/test/java/org/opensearch/client/NodesResponseHeaderTestUtils.java
index 9591cff16f121..32d9203480342 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/NodesResponseHeaderTestUtils.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/NodesResponseHeaderTestUtils.java
@@ -32,8 +32,8 @@
 package org.opensearch.client;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/OpenSearchRestHighLevelClientTestCase.java b/client/rest-high-level/src/test/java/org/opensearch/client/OpenSearchRestHighLevelClientTestCase.java
index efac508cf6814..6701124759f9f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/OpenSearchRestHighLevelClientTestCase.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/OpenSearchRestHighLevelClientTestCase.java
@@ -33,7 +33,6 @@
 package org.opensearch.client;
 
 import org.apache.http.util.EntityUtils;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.TaskGroup;
@@ -48,18 +47,20 @@
 import org.opensearch.client.indices.CreateIndexRequest;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedRunnable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.Pipeline;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchModule;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -221,7 +222,7 @@ protected static void createFieldAddingPipleine(String id, String fieldName, Str
             .endArray()
             .endObject();
 
-        createPipeline(new PutPipelineRequest(id, BytesReference.bytes(pipeline), XContentType.JSON));
+        createPipeline(new PutPipelineRequest(id, BytesReference.bytes(pipeline), MediaTypeRegistry.JSON));
     }
 
     protected static void createPipeline(String pipelineId) throws IOException {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/PitIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/PitIT.java
new file mode 100644
index 0000000000000..5ec1da77a6795
--- /dev/null
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/PitIT.java
@@ -0,0 +1,136 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client;
+
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.client.methods.HttpPut;
+import org.opensearch.OpenSearchStatusException;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitInfo;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.GetAllPitNodesResponse;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+/**
+ * Tests point in time API with rest high level client
+ */
+public class PitIT extends OpenSearchRestHighLevelClientTestCase {
+
+    @Before
+    public void indexDocuments() throws IOException {
+        Request doc1 = new Request(HttpPut.METHOD_NAME, "/index/_doc/1");
+        doc1.setJsonEntity("{\"type\":\"type1\", \"id\":1, \"num\":10, \"num2\":50}");
+        client().performRequest(doc1);
+        Request doc2 = new Request(HttpPut.METHOD_NAME, "/index/_doc/2");
+        doc2.setJsonEntity("{\"type\":\"type1\", \"id\":2, \"num\":20, \"num2\":40}");
+        client().performRequest(doc2);
+        Request doc3 = new Request(HttpPut.METHOD_NAME, "/index/_doc/3");
+        doc3.setJsonEntity("{\"type\":\"type1\", \"id\":3, \"num\":50, \"num2\":35}");
+        client().performRequest(doc3);
+        Request doc4 = new Request(HttpPut.METHOD_NAME, "/index/_doc/4");
+        doc4.setJsonEntity("{\"type\":\"type2\", \"id\":4, \"num\":100, \"num2\":10}");
+        client().performRequest(doc4);
+        Request doc5 = new Request(HttpPut.METHOD_NAME, "/index/_doc/5");
+        doc5.setJsonEntity("{\"type\":\"type2\", \"id\":5, \"num\":100, \"num2\":10}");
+        client().performRequest(doc5);
+        client().performRequest(new Request(HttpPost.METHOD_NAME, "/_refresh"));
+    }
+
+    public void testCreateAndDeletePit() throws IOException {
+        CreatePitRequest pitRequest = new CreatePitRequest(new TimeValue(1, TimeUnit.DAYS), true, "index");
+        CreatePitResponse createPitResponse = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+        assertTrue(createPitResponse.getId() != null);
+        assertEquals(1, createPitResponse.getTotalShards());
+        assertEquals(1, createPitResponse.getSuccessfulShards());
+        assertEquals(0, createPitResponse.getFailedShards());
+        assertEquals(0, createPitResponse.getSkippedShards());
+        GetAllPitNodesResponse getAllPitResponse = highLevelClient().getAllPits(RequestOptions.DEFAULT);
+        List<String> pits = getAllPitResponse.getPitInfos().stream().map(r -> r.getPitId()).collect(Collectors.toList());
+        assertTrue(pits.contains(createPitResponse.getId()));
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(createPitResponse.getId());
+        DeletePitRequest deletePitRequest = new DeletePitRequest(pitIds);
+        DeletePitResponse deletePitResponse = execute(deletePitRequest, highLevelClient()::deletePit, highLevelClient()::deletePitAsync);
+        assertTrue(deletePitResponse.getDeletePitResults().get(0).isSuccessful());
+        assertTrue(deletePitResponse.getDeletePitResults().get(0).getPitId().equals(createPitResponse.getId()));
+    }
+
+    public void testDeleteAllAndListAllPits() throws IOException, InterruptedException {
+        CreatePitRequest pitRequest = new CreatePitRequest(new TimeValue(1, TimeUnit.DAYS), true, "index");
+        CreatePitResponse pitResponse = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+        CreatePitResponse pitResponse1 = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+        assertTrue(pitResponse.getId() != null);
+        assertTrue(pitResponse1.getId() != null);
+        DeletePitResponse deletePitResponse = highLevelClient().deleteAllPits(RequestOptions.DEFAULT);
+        for (DeletePitInfo deletePitInfo : deletePitResponse.getDeletePitResults()) {
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        pitResponse = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+        pitResponse1 = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+        assertTrue(pitResponse.getId() != null);
+        assertTrue(pitResponse1.getId() != null);
+        GetAllPitNodesResponse getAllPitResponse = highLevelClient().getAllPits(RequestOptions.DEFAULT);
+
+        List<String> pits = getAllPitResponse.getPitInfos().stream().map(r -> r.getPitId()).collect(Collectors.toList());
+        assertTrue(pits.contains(pitResponse.getId()));
+        assertTrue(pits.contains(pitResponse1.getId()));
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<DeletePitResponse> deletePitListener = new ActionListener<>() {
+            @Override
+            public void onResponse(DeletePitResponse response) {
+                countDownLatch.countDown();
+                for (DeletePitInfo deletePitInfo : response.getDeletePitResults()) {
+                    assertTrue(deletePitInfo.isSuccessful());
+                }
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                countDownLatch.countDown();
+                if (!(e instanceof OpenSearchStatusException)) {
+                    throw new AssertionError("Delete all failed");
+                }
+            }
+        };
+        final CreatePitResponse pitResponse3 = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+
+        ActionListener<GetAllPitNodesResponse> getPitsListener = new ActionListener<GetAllPitNodesResponse>() {
+            @Override
+            public void onResponse(GetAllPitNodesResponse response) {
+                List<String> pits = response.getPitInfos().stream().map(r -> r.getPitId()).collect(Collectors.toList());
+                assertTrue(pits.contains(pitResponse3.getId()));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                if (!(e instanceof OpenSearchStatusException)) {
+                    throw new AssertionError("List all PITs failed", e);
+                }
+            }
+        };
+        highLevelClient().getAllPitsAsync(RequestOptions.DEFAULT, getPitsListener);
+        highLevelClient().deleteAllPitsAsync(RequestOptions.DEFAULT, deletePitListener);
+        assertTrue(countDownLatch.await(10, TimeUnit.SECONDS));
+        // validate no pits case
+        getAllPitResponse = highLevelClient().getAllPits(RequestOptions.DEFAULT);
+        assertTrue(getAllPitResponse.getPitInfos().size() == 0);
+        highLevelClient().deleteAllPitsAsync(RequestOptions.DEFAULT, deletePitListener);
+    }
+}
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/RankEvalIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/RankEvalIT.java
index 07e5b1627942e..47add92ecaccd 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/RankEvalIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/RankEvalIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.junit.Before;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.index.query.MatchAllQueryBuilder;
@@ -50,6 +49,7 @@
 import org.opensearch.index.rankeval.RatedSearchHit;
 import org.opensearch.index.rankeval.RecallAtK;
 import org.opensearch.search.builder.SearchSourceBuilder;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/ReindexIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/ReindexIT.java
index 78fb2aef02ee0..2457bafdc6a22 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/ReindexIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/ReindexIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.client;
 
 import org.opensearch.OpenSearchStatusException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkRequest;
@@ -42,15 +41,16 @@
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.client.tasks.TaskSubmissionResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.reindex.BulkByScrollResponse;
 import org.opensearch.index.reindex.DeleteByQueryAction;
 import org.opensearch.index.reindex.DeleteByQueryRequest;
 import org.opensearch.index.reindex.ReindexRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.RawTaskStatus;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -76,9 +76,9 @@ public void testReindex() throws IOException {
             createIndex(sourceIndex, settings);
             createIndex(destinationIndex, settings);
             BulkRequest bulkRequest = new BulkRequest().add(
-                new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON)
+                new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON)
             )
-                .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
+                .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), MediaTypeRegistry.JSON))
                 .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
             assertEquals(RestStatus.OK, highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status());
         }
@@ -112,10 +112,9 @@ public void testReindex() throws IOException {
             reindexRequest.setRefresh(true);
             reindexRequest.setRequireAlias(true);
 
-            OpenSearchStatusException exception = expectThrows(
-                OpenSearchStatusException.class,
-                () -> { execute(reindexRequest, highLevelClient()::reindex, highLevelClient()::reindexAsync); }
-            );
+            OpenSearchStatusException exception = expectThrows(OpenSearchStatusException.class, () -> {
+                execute(reindexRequest, highLevelClient()::reindex, highLevelClient()::reindexAsync);
+            });
             assertEquals(RestStatus.NOT_FOUND, exception.status());
             assertEquals(
                 "OpenSearch exception [type=index_not_found_exception, reason=no such index [dest] and [require_alias] request flag is [true] and [dest] is not an alias]",
@@ -133,9 +132,9 @@ public void testReindexTask() throws Exception {
             createIndex(sourceIndex, settings);
             createIndex(destinationIndex, settings);
             BulkRequest bulkRequest = new BulkRequest().add(
-                new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON)
+                new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON)
             )
-                .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
+                .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), MediaTypeRegistry.JSON))
                 .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
             assertEquals(RestStatus.OK, highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status());
         }
@@ -164,9 +163,9 @@ public void testReindexConflict() throws IOException {
         createIndex(sourceIndex, settings);
         createIndex(destIndex, settings);
         final BulkRequest bulkRequest = new BulkRequest().add(
-            new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON)
+            new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON)
         )
-            .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", "bar"), XContentType.JSON))
+            .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON))
             .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
         assertThat(highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status(), equalTo(RestStatus.OK));
 
@@ -206,10 +205,10 @@ public void testDeleteByQuery() throws Exception {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), XContentType.JSON)
+                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), XContentType.JSON))
-                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), XContentType.JSON))
+                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), MediaTypeRegistry.JSON))
+                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), MediaTypeRegistry.JSON))
                         .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
@@ -306,10 +305,10 @@ public void testDeleteByQueryTask() throws Exception {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), XContentType.JSON)
+                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), XContentType.JSON))
-                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), XContentType.JSON))
+                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), MediaTypeRegistry.JSON))
+                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), MediaTypeRegistry.JSON))
                         .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/RequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/RequestConvertersTests.java
index 32c6cde0725b4..2be3c27c6b5ce 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/RequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/RequestConvertersTests.java
@@ -53,6 +53,8 @@
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.ClearScrollRequest;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.DeletePitRequest;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchScrollRequest;
@@ -60,8 +62,8 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.WriteRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.action.support.master.MasterNodeRequest;
 import org.opensearch.action.support.replication.ReplicationRequest;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.client.RequestConverters.EndpointBuilder;
@@ -71,20 +73,22 @@
 import org.opensearch.client.core.TermVectorsRequest;
 import org.opensearch.client.indices.AnalyzeRequest;
 import org.opensearch.common.CheckedBiConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.MatchAllQueryBuilder;
@@ -115,7 +119,6 @@
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.search.suggest.SuggestBuilder;
 import org.opensearch.search.suggest.completion.CompletionSuggestionBuilder;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 import org.hamcrest.Matchers;
@@ -131,6 +134,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.StringJoiner;
+import java.util.concurrent.TimeUnit;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -806,7 +810,7 @@ public void testUpdate() throws IOException {
 
         UpdateRequest parsedUpdateRequest = new UpdateRequest();
 
-        XContentType entityContentType = XContentType.fromMediaTypeOrFormat(entity.getContentType().getValue());
+        MediaType entityContentType = MediaType.fromMediaType(entity.getContentType().getValue());
         try (XContentParser parser = createParser(entityContentType.xContent(), entity.getContent())) {
             parsedUpdateRequest.fromXContent(parser);
         }
@@ -848,7 +852,7 @@ private static void setRandomIfSeqNoAndTerm(DocWriteRequest<?> request, Map<Stri
     public void testUpdateWithDifferentContentTypes() {
         IllegalStateException exception = expectThrows(IllegalStateException.class, () -> {
             UpdateRequest updateRequest = new UpdateRequest();
-            updateRequest.doc(new IndexRequest().source(singletonMap("field", "doc"), XContentType.JSON));
+            updateRequest.doc(new IndexRequest().source(singletonMap("field", "doc"), MediaTypeRegistry.JSON));
             updateRequest.upsert(new IndexRequest().source(singletonMap("field", "upsert"), XContentType.YAML));
             RequestConverters.update(updateRequest);
         });
@@ -872,7 +876,7 @@ public void testBulk() throws IOException {
 
         setRandomRefreshPolicy(bulkRequest::setRefreshPolicy, expectedParams);
 
-        XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+        MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
 
         int nbItems = randomIntBetween(10, 100);
         DocWriteRequest<?>[] requests = new DocWriteRequest<?>[nbItems];
@@ -880,21 +884,21 @@ public void testBulk() throws IOException {
             String index = randomAlphaOfLength(5);
             String id = randomAlphaOfLength(5);
 
-            BytesReference source = RandomObjects.randomSource(random(), xContentType);
+            BytesReference source = RandomObjects.randomSource(random(), mediaType);
             DocWriteRequest.OpType opType = randomFrom(DocWriteRequest.OpType.values());
 
             DocWriteRequest<?> docWriteRequest;
             if (opType == DocWriteRequest.OpType.INDEX) {
-                IndexRequest indexRequest = new IndexRequest(index).id(id).source(source, xContentType);
+                IndexRequest indexRequest = new IndexRequest(index).id(id).source(source, mediaType);
                 docWriteRequest = indexRequest;
                 if (randomBoolean()) {
                     indexRequest.setPipeline(randomAlphaOfLength(5));
                 }
             } else if (opType == DocWriteRequest.OpType.CREATE) {
-                IndexRequest createRequest = new IndexRequest(index).id(id).source(source, xContentType).create(true);
+                IndexRequest createRequest = new IndexRequest(index).id(id).source(source, mediaType).create(true);
                 docWriteRequest = createRequest;
             } else if (opType == DocWriteRequest.OpType.UPDATE) {
-                final UpdateRequest updateRequest = new UpdateRequest(index, id).doc(new IndexRequest().source(source, xContentType));
+                final UpdateRequest updateRequest = new UpdateRequest(index, id).doc(new IndexRequest().source(source, mediaType));
                 docWriteRequest = updateRequest;
                 if (randomBoolean()) {
                     updateRequest.retryOnConflict(randomIntBetween(1, 5));
@@ -923,14 +927,14 @@ public void testBulk() throws IOException {
         assertEquals("/_bulk", request.getEndpoint());
         assertEquals(expectedParams, request.getParameters());
         assertEquals(HttpPost.METHOD_NAME, request.getMethod());
-        assertEquals(xContentType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+        assertEquals(mediaType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
         byte[] content = new byte[(int) request.getEntity().getContentLength()];
         try (InputStream inputStream = request.getEntity().getContent()) {
             Streams.readFully(inputStream, content);
         }
 
         BulkRequest parsedBulkRequest = new BulkRequest();
-        parsedBulkRequest.add(content, 0, content.length, xContentType);
+        parsedBulkRequest.add(content, 0, content.length, mediaType);
         assertEquals(bulkRequest.numberOfActions(), parsedBulkRequest.numberOfActions());
 
         for (int i = 0; i < bulkRequest.numberOfActions(); i++) {
@@ -952,7 +956,7 @@ public void testBulk() throws IOException {
                 IndexRequest parsedIndexRequest = (IndexRequest) parsedRequest;
 
                 assertEquals(indexRequest.getPipeline(), parsedIndexRequest.getPipeline());
-                assertToXContentEquivalent(indexRequest.source(), parsedIndexRequest.source(), xContentType);
+                assertToXContentEquivalent(indexRequest.source(), parsedIndexRequest.source(), mediaType);
             } else if (opType == DocWriteRequest.OpType.UPDATE) {
                 UpdateRequest updateRequest = (UpdateRequest) originalRequest;
                 UpdateRequest parsedUpdateRequest = (UpdateRequest) parsedRequest;
@@ -960,7 +964,7 @@ public void testBulk() throws IOException {
                 assertEquals(updateRequest.retryOnConflict(), parsedUpdateRequest.retryOnConflict());
                 assertEquals(updateRequest.fetchSource(), parsedUpdateRequest.fetchSource());
                 if (updateRequest.doc() != null) {
-                    assertToXContentEquivalent(updateRequest.doc().source(), parsedUpdateRequest.doc().source(), xContentType);
+                    assertToXContentEquivalent(updateRequest.doc().source(), parsedUpdateRequest.doc().source(), mediaType);
                 } else {
                     assertNull(parsedUpdateRequest.doc());
                 }
@@ -976,34 +980,34 @@ public void testBulkWithDifferentContentTypes() throws IOException {
             bulkRequest.add(new DeleteRequest("index", "2"));
 
             Request request = RequestConverters.bulk(bulkRequest);
-            assertEquals(XContentType.JSON.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+            assertEquals(MediaTypeRegistry.JSON.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
         }
         {
-            XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+            MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
             BulkRequest bulkRequest = new BulkRequest();
             bulkRequest.add(new DeleteRequest("index", "0"));
-            bulkRequest.add(new IndexRequest("index").id("0").source(singletonMap("field", "value"), xContentType));
+            bulkRequest.add(new IndexRequest("index").id("0").source(singletonMap("field", "value"), mediaType));
             bulkRequest.add(new DeleteRequest("index", "2"));
 
             Request request = RequestConverters.bulk(bulkRequest);
-            assertEquals(xContentType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+            assertEquals(mediaType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
         }
         {
-            XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+            MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
             UpdateRequest updateRequest = new UpdateRequest("index", "0");
             if (randomBoolean()) {
-                updateRequest.doc(new IndexRequest().source(singletonMap("field", "value"), xContentType));
+                updateRequest.doc(new IndexRequest().source(singletonMap("field", "value"), mediaType));
             } else {
-                updateRequest.upsert(new IndexRequest().source(singletonMap("field", "value"), xContentType));
+                updateRequest.upsert(new IndexRequest().source(singletonMap("field", "value"), mediaType));
             }
 
             Request request = RequestConverters.bulk(new BulkRequest().add(updateRequest));
-            assertEquals(xContentType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+            assertEquals(mediaType.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
         }
         {
             BulkRequest bulkRequest = new BulkRequest();
             bulkRequest.add(new IndexRequest("index").id("0").source(singletonMap("field", "value"), XContentType.SMILE));
-            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), XContentType.JSON));
+            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), MediaTypeRegistry.JSON));
             IllegalArgumentException exception = expectThrows(IllegalArgumentException.class, () -> RequestConverters.bulk(bulkRequest));
             assertEquals(
                 "Mismatching content-type found for request with content-type [JSON], " + "previous requests have content-type [SMILE]",
@@ -1012,10 +1016,10 @@ public void testBulkWithDifferentContentTypes() throws IOException {
         }
         {
             BulkRequest bulkRequest = new BulkRequest();
-            bulkRequest.add(new IndexRequest("index").id("0").source(singletonMap("field", "value"), XContentType.JSON));
-            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), XContentType.JSON));
+            bulkRequest.add(new IndexRequest("index").id("0").source(singletonMap("field", "value"), MediaTypeRegistry.JSON));
+            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), MediaTypeRegistry.JSON));
             bulkRequest.add(
-                new UpdateRequest("index", "2").doc(new IndexRequest().source(singletonMap("field", "value"), XContentType.JSON))
+                new UpdateRequest("index", "2").doc(new IndexRequest().source(singletonMap("field", "value"), MediaTypeRegistry.JSON))
                     .upsert(new IndexRequest().source(singletonMap("field", "value"), XContentType.SMILE))
             );
             IllegalArgumentException exception = expectThrows(IllegalArgumentException.class, () -> RequestConverters.bulk(bulkRequest));
@@ -1028,10 +1032,10 @@ public void testBulkWithDifferentContentTypes() throws IOException {
             XContentType xContentType = randomFrom(XContentType.CBOR, XContentType.YAML);
             BulkRequest bulkRequest = new BulkRequest();
             bulkRequest.add(new DeleteRequest("index", "0"));
-            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), XContentType.JSON));
+            bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), MediaTypeRegistry.JSON));
             bulkRequest.add(new DeleteRequest("index", "2"));
             bulkRequest.add(new DeleteRequest("index", "3"));
-            bulkRequest.add(new IndexRequest("index").id("4").source(singletonMap("field", "value"), XContentType.JSON));
+            bulkRequest.add(new IndexRequest("index").id("4").source(singletonMap("field", "value"), MediaTypeRegistry.JSON));
             bulkRequest.add(new IndexRequest("index").id("1").source(singletonMap("field", "value"), xContentType));
             IllegalArgumentException exception = expectThrows(IllegalArgumentException.class, () -> RequestConverters.bulk(bulkRequest));
             assertEquals(
@@ -1044,9 +1048,9 @@ public void testBulkWithDifferentContentTypes() throws IOException {
     public void testGlobalPipelineOnBulkRequest() throws IOException {
         BulkRequest bulkRequest = new BulkRequest();
         bulkRequest.pipeline("xyz");
-        bulkRequest.add(new IndexRequest("test").id("11").source(XContentType.JSON, "field", "bulk1"));
-        bulkRequest.add(new IndexRequest("test").id("12").source(XContentType.JSON, "field", "bulk2"));
-        bulkRequest.add(new IndexRequest("test").id("13").source(XContentType.JSON, "field", "bulk3"));
+        bulkRequest.add(new IndexRequest("test").id("11").source(MediaTypeRegistry.JSON, "field", "bulk1"));
+        bulkRequest.add(new IndexRequest("test").id("12").source(MediaTypeRegistry.JSON, "field", "bulk2"));
+        bulkRequest.add(new IndexRequest("test").id("13").source(MediaTypeRegistry.JSON, "field", "bulk3"));
 
         Request request = RequestConverters.bulk(bulkRequest);
 
@@ -1303,6 +1307,47 @@ public void testClearScroll() throws IOException {
         assertEquals(REQUEST_BODY_CONTENT_TYPE.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
     }
 
+    public void testCreatePit() throws IOException {
+        String[] indices = randomIndicesNames(0, 5);
+        Map<String, String> expectedParams = new HashMap<>();
+        expectedParams.put("keep_alive", "1d");
+        expectedParams.put("allow_partial_pit_creation", "true");
+        CreatePitRequest createPitRequest = new CreatePitRequest(new TimeValue(1, TimeUnit.DAYS), true, indices);
+        setRandomIndicesOptions(createPitRequest::indicesOptions, createPitRequest::indicesOptions, expectedParams);
+        Request request = RequestConverters.createPit(createPitRequest);
+        StringJoiner endpoint = new StringJoiner("/", "/", "");
+        String index = String.join(",", indices);
+        if (Strings.hasLength(index)) {
+            endpoint.add(index);
+        }
+        endpoint.add("_search/point_in_time");
+        assertEquals(HttpPost.METHOD_NAME, request.getMethod());
+        assertEquals(endpoint.toString(), request.getEndpoint());
+        assertEquals(expectedParams, request.getParameters());
+        assertToXContentBody(createPitRequest, request.getEntity());
+        assertEquals(REQUEST_BODY_CONTENT_TYPE.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+    }
+
+    public void testDeletePit() throws IOException {
+        List<String> pitIdsList = new ArrayList<>();
+        pitIdsList.add("pitId1");
+        pitIdsList.add("pitId2");
+        DeletePitRequest deletePitRequest = new DeletePitRequest(pitIdsList);
+        Request request = RequestConverters.deletePit(deletePitRequest);
+        String endpoint = "/_search/point_in_time";
+        assertEquals(HttpDelete.METHOD_NAME, request.getMethod());
+        assertEquals(endpoint, request.getEndpoint());
+        assertToXContentBody(deletePitRequest, request.getEntity());
+        assertEquals(REQUEST_BODY_CONTENT_TYPE.mediaTypeWithoutParameters(), request.getEntity().getContentType().getValue());
+    }
+
+    public void testDeleteAllPits() {
+        Request request = RequestConverters.deleteAllPits();
+        String endpoint = "/_search/point_in_time/_all";
+        assertEquals(HttpDelete.METHOD_NAME, request.getMethod());
+        assertEquals(endpoint, request.getEndpoint());
+    }
+
     public void testSearchTemplate() throws Exception {
         // Create a random request.
         String[] indices = randomIndicesNames(0, 5);
@@ -1411,8 +1456,11 @@ public void testMultiSearchTemplate() throws Exception {
         assertEquals(expectedParams, multiRequest.getParameters());
 
         HttpEntity actualEntity = multiRequest.getEntity();
-        byte[] expectedBytes = MultiSearchTemplateRequest.writeMultiLineFormat(multiSearchTemplateRequest, XContentType.JSON.xContent());
-        assertEquals(XContentType.JSON.mediaTypeWithoutParameters(), actualEntity.getContentType().getValue());
+        byte[] expectedBytes = MultiSearchTemplateRequest.writeMultiLineFormat(
+            multiSearchTemplateRequest,
+            MediaTypeRegistry.JSON.xContent()
+        );
+        assertEquals(MediaTypeRegistry.JSON.mediaTypeWithoutParameters(), actualEntity.getContentType().getValue());
         assertEquals(new BytesArray(expectedBytes), new BytesArray(EntityUtils.toByteArray(actualEntity)));
     }
 
@@ -1718,8 +1766,12 @@ public void testDeleteScriptRequest() {
     }
 
     static void assertToXContentBody(ToXContent expectedBody, HttpEntity actualEntity) throws IOException {
-        BytesReference expectedBytes = XContentHelper.toXContent(expectedBody, REQUEST_BODY_CONTENT_TYPE, false);
-        assertEquals(XContentType.JSON.mediaTypeWithoutParameters(), actualEntity.getContentType().getValue());
+        BytesReference expectedBytes = org.opensearch.core.xcontent.XContentHelper.toXContent(
+            expectedBody,
+            REQUEST_BODY_CONTENT_TYPE,
+            false
+        );
+        assertEquals(MediaTypeRegistry.JSON.mediaTypeWithoutParameters(), actualEntity.getContentType().getValue());
         assertEquals(expectedBytes, new BytesArray(EntityUtils.toByteArray(actualEntity)));
     }
 
@@ -1868,12 +1920,12 @@ public void testCreateContentType() {
     }
 
     public void testEnforceSameContentType() {
-        XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
-        IndexRequest indexRequest = new IndexRequest().source(singletonMap("field", "value"), xContentType);
-        assertEquals(xContentType, enforceSameContentType(indexRequest, null));
-        assertEquals(xContentType, enforceSameContentType(indexRequest, xContentType));
+        MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
+        IndexRequest indexRequest = new IndexRequest().source(singletonMap("field", "value"), mediaType);
+        assertEquals(mediaType, enforceSameContentType(indexRequest, null));
+        assertEquals(mediaType, enforceSameContentType(indexRequest, mediaType));
 
-        XContentType bulkContentType = randomBoolean() ? xContentType : null;
+        MediaType bulkContentType = randomBoolean() ? mediaType : null;
 
         IllegalArgumentException exception = expectThrows(
             IllegalArgumentException.class,
@@ -1893,18 +1945,18 @@ public void testEnforceSameContentType() {
             exception.getMessage()
         );
 
-        XContentType requestContentType = xContentType == XContentType.JSON ? XContentType.SMILE : XContentType.JSON;
+        MediaType requestContentType = mediaType == MediaTypeRegistry.JSON ? XContentType.SMILE : MediaTypeRegistry.JSON;
 
         exception = expectThrows(
             IllegalArgumentException.class,
-            () -> enforceSameContentType(new IndexRequest().source(singletonMap("field", "value"), requestContentType), xContentType)
+            () -> enforceSameContentType(new IndexRequest().source(singletonMap("field", "value"), requestContentType), mediaType)
         );
         assertEquals(
             "Mismatching content-type found for request with content-type ["
                 + requestContentType
                 + "], "
                 + "previous requests have content-type ["
-                + xContentType
+                + mediaType
                 + "]",
             exception.getMessage()
         );
@@ -2105,8 +2157,8 @@ static void setRandomTimeoutTimeValue(Consumer<TimeValue> setter, TimeValue defa
         }
     }
 
-    static void setRandomMasterTimeout(MasterNodeRequest<?> request, Map<String, String> expectedParams) {
-        setRandomMasterTimeout(request::masterNodeTimeout, expectedParams);
+    static void setRandomMasterTimeout(ClusterManagerNodeRequest<?> request, Map<String, String> expectedParams) {
+        setRandomMasterTimeout(request::clusterManagerNodeTimeout, expectedParams);
     }
 
     static void setRandomMasterTimeout(TimedRequest request, Map<String, String> expectedParams) {
@@ -2122,7 +2174,7 @@ static void setRandomMasterTimeout(Consumer<String> setter, Map<String, String>
             setter.accept(masterTimeout);
             expectedParams.put("master_timeout", masterTimeout);
         } else {
-            expectedParams.put("master_timeout", MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT.getStringRep());
+            expectedParams.put("master_timeout", ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT.getStringRep());
         }
     }
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientExtTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientExtTests.java
index dbdf7eba3dca4..7658aa3c2c765 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientExtTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientExtTests.java
@@ -35,11 +35,11 @@
 import org.apache.http.HttpEntity;
 import org.apache.http.entity.ContentType;
 import org.apache.http.nio.entity.NStringEntity;
-import org.junit.Before;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientTests.java
index 73ce7d1b2b794..b0476a65e6d8c 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.client;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
 import org.apache.http.HttpResponse;
@@ -47,7 +48,6 @@
 import org.apache.http.nio.entity.NByteArrayEntity;
 import org.apache.http.nio.entity.NStringEntity;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.search.ClearScrollRequest;
@@ -59,16 +59,18 @@
 import org.opensearch.client.core.MainRequest;
 import org.opensearch.client.core.MainResponse;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.cbor.CborXContent;
 import org.opensearch.common.xcontent.smile.SmileXContent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.rankeval.DiscountedCumulativeGain;
 import org.opensearch.index.rankeval.EvaluationMetric;
 import org.opensearch.index.rankeval.ExpectedReciprocalRank;
@@ -77,14 +79,13 @@
 import org.opensearch.index.rankeval.PrecisionAtK;
 import org.opensearch.index.rankeval.RecallAtK;
 import org.opensearch.join.aggregations.ChildrenAggregationBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
 import org.opensearch.search.suggest.Suggest;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.yaml.restspec.ClientYamlSuiteRestApi;
 import org.opensearch.test.rest.yaml.restspec.ClientYamlSuiteRestSpec;
 import org.hamcrest.Matchers;
@@ -108,7 +109,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.hamcrest.CoreMatchers.endsWith;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -134,6 +135,8 @@ public class RestHighLevelClientTests extends OpenSearchTestCase {
         // core
         "ping",
         "info",
+        "delete_all_pits",
+        "get_all_pits",
         // security
         "security.get_ssl_certificates",
         "security.authenticate",
@@ -284,6 +287,20 @@ public ActionRequestValidationException validate() {
         }
     }
 
+    public void testNullableActionListener() {
+        ActionRequest request = new ActionRequest() {
+            @Override
+            public ActionRequestValidationException validate() {
+                return null;
+            }
+        };
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> restHighLevelClient.performRequestAsync(request, null, RequestOptions.DEFAULT, null, null, null)
+        );
+    }
+
     public void testParseEntity() throws IOException {
         {
             IllegalStateException ise = expectThrows(IllegalStateException.class, () -> restHighLevelClient.parseEntity(null, null));
@@ -411,13 +428,9 @@ public void testPerformRequestOnSuccess() throws IOException {
         {
             IOException ioe = expectThrows(
                 IOException.class,
-                () -> restHighLevelClient.performRequest(
-                    mainRequest,
-                    requestConverter,
-                    RequestOptions.DEFAULT,
-                    response -> { throw new IllegalStateException(); },
-                    Collections.emptySet()
-                )
+                () -> restHighLevelClient.performRequest(mainRequest, requestConverter, RequestOptions.DEFAULT, response -> {
+                    throw new IllegalStateException();
+                }, Collections.emptySet())
             );
             assertEquals(
                 "Unable to parse response body for Response{requestLine=GET / http/1.1, host=http://localhost:9200, "
@@ -559,13 +572,9 @@ public void testPerformRequestOnResponseExceptionWithIgnoresErrorNoBody() throws
         when(restClient.performRequest(any(Request.class))).thenThrow(responseException);
         OpenSearchException openSearchException = expectThrows(
             OpenSearchException.class,
-            () -> restHighLevelClient.performRequest(
-                mainRequest,
-                requestConverter,
-                RequestOptions.DEFAULT,
-                response -> { throw new IllegalStateException(); },
-                Collections.singleton(404)
-            )
+            () -> restHighLevelClient.performRequest(mainRequest, requestConverter, RequestOptions.DEFAULT, response -> {
+                throw new IllegalStateException();
+            }, Collections.singleton(404))
         );
         assertEquals(RestStatus.NOT_FOUND, openSearchException.status());
         assertSame(responseException, openSearchException.getCause());
@@ -582,13 +591,9 @@ public void testPerformRequestOnResponseExceptionWithIgnoresErrorValidBody() thr
         when(restClient.performRequest(any(Request.class))).thenThrow(responseException);
         OpenSearchException openSearchException = expectThrows(
             OpenSearchException.class,
-            () -> restHighLevelClient.performRequest(
-                mainRequest,
-                requestConverter,
-                RequestOptions.DEFAULT,
-                response -> { throw new IllegalStateException(); },
-                Collections.singleton(404)
-            )
+            () -> restHighLevelClient.performRequest(mainRequest, requestConverter, RequestOptions.DEFAULT, response -> {
+                throw new IllegalStateException();
+            }, Collections.singleton(404))
         );
         assertEquals(RestStatus.NOT_FOUND, openSearchException.status());
         assertSame(responseException, openSearchException.getSuppressed()[0]);
@@ -841,7 +846,6 @@ public void testApiNamingConventions() throws Exception {
             "create",
             "get_script_context",
             "get_script_languages",
-            "indices.exists_type",
             "indices.get_upgrade",
             "indices.put_alias",
             "render_search_template",
@@ -872,7 +876,15 @@ public void testApiNamingConventions() throws Exception {
             "nodes.hot_threads",
             "nodes.usage",
             "nodes.reload_secure_settings",
-            "search_shards", };
+            "search_shards",
+            "remote_store.restore",
+            "remote_store.stats",
+            "cluster.put_weighted_routing",
+            "cluster.get_weighted_routing",
+            "cluster.delete_weighted_routing",
+            "cluster.put_decommission_awareness",
+            "cluster.get_decommission_awareness",
+            "cluster.delete_decommission_awareness", };
         List<String> booleanReturnMethods = Arrays.asList("security.enable_user", "security.disable_user", "security.change_password");
         Set<String> deprecatedMethods = new HashSet<>();
         deprecatedMethods.add("indices.force_merge");
@@ -985,37 +997,34 @@ private static void assertSyncMethod(Method method, String apiName, List<String>
         }
 
         assertEquals("incorrect number of exceptions for method [" + method + "]", 1, method.getExceptionTypes().length);
+        final Class<?>[] parameterTypes = method.getParameterTypes();
         // a few methods don't accept a request object as argument
         if (APIS_WITHOUT_REQUEST_OBJECT.contains(apiName)) {
-            assertEquals("incorrect number of arguments for method [" + method + "]", 1, method.getParameterTypes().length);
-            assertThat(
-                "the parameter to method [" + method + "] is the wrong type",
-                method.getParameterTypes()[0],
-                equalTo(RequestOptions.class)
-            );
+            assertEquals("incorrect number of arguments for method [" + method + "]", 1, method.getParameterCount());
+            assertThat("the parameter to method [" + method + "] is the wrong type", parameterTypes[0], equalTo(RequestOptions.class));
         } else {
-            assertEquals("incorrect number of arguments for method [" + method + "]", 2, method.getParameterTypes().length);
+            assertEquals("incorrect number of arguments for method [" + method + "]", 2, method.getParameterCount());
             // This is no longer true for all methods. Some methods can contain these 2 args backwards because of deprecation
-            if (method.getParameterTypes()[0].equals(RequestOptions.class)) {
+            if (parameterTypes[0].equals(RequestOptions.class)) {
                 assertThat(
                     "the first parameter to method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[0],
+                    parameterTypes[0],
                     equalTo(RequestOptions.class)
                 );
                 assertThat(
                     "the second parameter to method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[1].getSimpleName(),
+                    parameterTypes[1].getSimpleName(),
                     endsWith("Request")
                 );
             } else {
                 assertThat(
                     "the first parameter to method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[0].getSimpleName(),
+                    parameterTypes[0].getSimpleName(),
                     endsWith("Request")
                 );
                 assertThat(
                     "the second parameter to method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[1],
+                    parameterTypes[1],
                     equalTo(RequestOptions.class)
                 );
             }
@@ -1029,39 +1038,40 @@ private static void assertAsyncMethod(Map<String, Set<Method>> methods, Method m
         );
         assertThat("async method [" + method + "] should return Cancellable", method.getReturnType(), equalTo(Cancellable.class));
         assertEquals("async method [" + method + "] should not throw any exceptions", 0, method.getExceptionTypes().length);
+        final Class<?>[] parameterTypes = method.getParameterTypes();
         if (APIS_WITHOUT_REQUEST_OBJECT.contains(apiName.replaceAll("_async$", ""))) {
-            assertEquals(2, method.getParameterTypes().length);
-            assertThat(method.getParameterTypes()[0], equalTo(RequestOptions.class));
-            assertThat(method.getParameterTypes()[1], equalTo(ActionListener.class));
+            assertEquals(2, parameterTypes.length);
+            assertThat(parameterTypes[0], equalTo(RequestOptions.class));
+            assertThat(parameterTypes[1], equalTo(ActionListener.class));
         } else {
-            assertEquals("async method [" + method + "] has the wrong number of arguments", 3, method.getParameterTypes().length);
+            assertEquals("async method [" + method + "] has the wrong number of arguments", 3, method.getParameterCount());
             // This is no longer true for all methods. Some methods can contain these 2 args backwards because of deprecation
-            if (method.getParameterTypes()[0].equals(RequestOptions.class)) {
+            if (parameterTypes[0].equals(RequestOptions.class)) {
                 assertThat(
                     "the first parameter to async method [" + method + "] should be a request type",
-                    method.getParameterTypes()[0],
+                    parameterTypes[0],
                     equalTo(RequestOptions.class)
                 );
                 assertThat(
                     "the second parameter to async method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[1].getSimpleName(),
+                    parameterTypes[1].getSimpleName(),
                     endsWith("Request")
                 );
             } else {
                 assertThat(
                     "the first parameter to async method [" + method + "] should be a request type",
-                    method.getParameterTypes()[0].getSimpleName(),
+                    parameterTypes[0].getSimpleName(),
                     endsWith("Request")
                 );
                 assertThat(
                     "the second parameter to async method [" + method + "] is the wrong type",
-                    method.getParameterTypes()[1],
+                    parameterTypes[1],
                     equalTo(RequestOptions.class)
                 );
             }
             assertThat(
                 "the third parameter to async method [" + method + "] is the wrong type",
-                method.getParameterTypes()[2],
+                parameterTypes[2],
                 equalTo(ActionListener.class)
             );
         }
@@ -1074,16 +1084,17 @@ private static void assertSubmitTaskMethod(
         ClientYamlSuiteRestSpec restSpec
     ) {
         String methodName = extractMethodName(apiName);
+        final Class<?>[] parameterTypes = method.getParameterTypes();
         assertTrue("submit task method [" + method.getName() + "] doesn't have corresponding sync method", methods.containsKey(methodName));
-        assertEquals("submit task method [" + method + "] has the wrong number of arguments", 2, method.getParameterTypes().length);
+        assertEquals("submit task method [" + method + "] has the wrong number of arguments", 2, method.getParameterCount());
         assertThat(
             "the first parameter to submit task method [" + method + "] is the wrong type",
-            method.getParameterTypes()[0].getSimpleName(),
+            parameterTypes[0].getSimpleName(),
             endsWith("Request")
         );
         assertThat(
             "the second parameter to submit task method [" + method + "] is the wrong type",
-            method.getParameterTypes()[1],
+            parameterTypes[1],
             equalTo(RequestOptions.class)
         );
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/SearchIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/SearchIT.java
index 19e287fb91be5..bb705aebd2fcf 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/SearchIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/SearchIT.java
@@ -43,6 +43,10 @@
 import org.opensearch.action.fieldcaps.FieldCapabilitiesResponse;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchRequest;
@@ -50,12 +54,12 @@
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.client.core.CountRequest;
 import org.opensearch.client.core.CountResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -63,7 +67,6 @@
 import org.opensearch.index.query.TermsQueryBuilder;
 import org.opensearch.join.aggregations.Children;
 import org.opensearch.join.aggregations.ChildrenAggregationBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.script.mustache.MultiSearchTemplateRequest;
@@ -79,6 +82,7 @@
 import org.opensearch.search.aggregations.bucket.composite.TermsValuesSourceBuilder;
 import org.opensearch.search.aggregations.bucket.range.Range;
 import org.opensearch.search.aggregations.bucket.range.RangeAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.RareTerms;
 import org.opensearch.search.aggregations.bucket.terms.RareTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
@@ -87,8 +91,10 @@
 import org.opensearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.WeightedAvg;
 import org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
 import org.opensearch.search.aggregations.support.MultiValuesSourceFieldConfig;
 import org.opensearch.search.aggregations.support.ValueType;
+import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
@@ -100,11 +106,14 @@
 import org.junit.Before;
 
 import java.io.IOException;
+import java.math.BigInteger;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
@@ -290,6 +299,67 @@ public void testSearchWithTermsAgg() throws IOException {
         assertEquals(0, type2.getAggregations().asList().size());
     }
 
+    public void testSearchWithMultiTermsAgg() throws IOException {
+        final String indexName = "multi_aggs";
+        Request createIndex = new Request(HttpPut.METHOD_NAME, "/" + indexName);
+        createIndex.setJsonEntity(
+            "{\n"
+                + "    \"mappings\": {\n"
+                + "        \"properties\" : {\n"
+                + "            \"username\" : {\n"
+                + "                \"type\" : \"keyword\"\n"
+                + "            },\n"
+                + "            \"rating\" : {\n"
+                + "                \"type\" : \"unsigned_long\"\n"
+                + "            }\n"
+                + "        }\n"
+                + "    }"
+                + "}"
+        );
+        client().performRequest(createIndex);
+
+        {
+            Request doc1 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/1");
+            doc1.setJsonEntity("{\"username\":\"bob\", \"rating\": 18446744073709551615}");
+            client().performRequest(doc1);
+            Request doc2 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/2");
+            doc2.setJsonEntity("{\"username\":\"tom\", \"rating\": 10223372036854775807}");
+            client().performRequest(doc2);
+            Request doc3 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/3");
+            doc3.setJsonEntity("{\"username\":\"john\"}");
+            client().performRequest(doc3);
+        }
+        client().performRequest(new Request(HttpPost.METHOD_NAME, "/_refresh"));
+
+        SearchRequest searchRequest = new SearchRequest().indices(indexName);
+        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
+        searchSourceBuilder.aggregation(
+            new MultiTermsAggregationBuilder("agg1").terms(
+                Arrays.asList(
+                    new MultiTermsValuesSourceConfig.Builder().setFieldName("username").build(),
+                    new MultiTermsValuesSourceConfig.Builder().setFieldName("rating").build()
+                )
+            )
+        );
+        searchSourceBuilder.size(0);
+        searchRequest.source(searchSourceBuilder);
+        SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
+        assertSearchHeader(searchResponse);
+        assertNull(searchResponse.getSuggest());
+        assertEquals(Collections.emptyMap(), searchResponse.getProfileResults());
+        assertEquals(0, searchResponse.getHits().getHits().length);
+        assertEquals(Float.NaN, searchResponse.getHits().getMaxScore(), 0f);
+        Terms termsAgg = searchResponse.getAggregations().get("agg1");
+        assertEquals("agg1", termsAgg.getName());
+        assertEquals(2, termsAgg.getBuckets().size());
+        Terms.Bucket bucket1 = termsAgg.getBucketByKey("bob|18446744073709551615");
+        assertEquals(1, bucket1.getDocCount());
+        assertEquals(0, bucket1.getAggregations().asList().size());
+        Terms.Bucket bucket2 = termsAgg.getBucketByKey("tom|10223372036854775807");
+        assertEquals(1, bucket2.getDocCount());
+        assertEquals(0, bucket2.getAggregations().asList().size());
+    }
+
     public void testSearchWithRareTermsAgg() throws IOException {
         SearchRequest searchRequest = new SearchRequest();
         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
@@ -698,7 +768,7 @@ public void testSearchScroll() throws Exception {
         for (int i = 0; i < 100; i++) {
             XContentBuilder builder = jsonBuilder().startObject().field("field", i).endObject();
             Request doc = new Request(HttpPut.METHOD_NAME, "/test/_doc/" + Integer.toString(i));
-            doc.setJsonEntity(Strings.toString(builder));
+            doc.setJsonEntity(builder.toString());
             client().performRequest(doc);
         }
         client().performRequest(new Request(HttpPost.METHOD_NAME, "/test/_refresh"));
@@ -762,6 +832,46 @@ public void testSearchScroll() throws Exception {
         }
     }
 
+    public void testSearchWithPit() throws Exception {
+        for (int i = 0; i < 100; i++) {
+            XContentBuilder builder = jsonBuilder().startObject().field("field", i).endObject();
+            Request doc = new Request(HttpPut.METHOD_NAME, "/test/_doc/" + Integer.toString(i));
+            doc.setJsonEntity(builder.toString());
+            client().performRequest(doc);
+        }
+        client().performRequest(new Request(HttpPost.METHOD_NAME, "/test/_refresh"));
+
+        CreatePitRequest pitRequest = new CreatePitRequest(new TimeValue(1, TimeUnit.DAYS), true, "test");
+        CreatePitResponse pitResponse = execute(pitRequest, highLevelClient()::createPit, highLevelClient()::createPitAsync);
+
+        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder().size(35)
+            .sort("field", SortOrder.ASC)
+            .pointInTimeBuilder(new PointInTimeBuilder(pitResponse.getId()));
+        SearchRequest searchRequest = new SearchRequest().source(searchSourceBuilder);
+        SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
+
+        try {
+            long counter = 0;
+            assertSearchHeader(searchResponse);
+            assertThat(searchResponse.getHits().getTotalHits().value, equalTo(100L));
+            assertThat(searchResponse.getHits().getHits().length, equalTo(35));
+            for (SearchHit hit : searchResponse.getHits()) {
+                assertThat(((Number) hit.getSortValues()[0]).longValue(), equalTo(counter++));
+            }
+        } finally {
+            List<String> pitIds = new ArrayList<>();
+            pitIds.add(pitResponse.getId());
+            DeletePitRequest deletePitRequest = new DeletePitRequest(pitIds);
+            DeletePitResponse deletePitResponse = execute(
+                deletePitRequest,
+                highLevelClient()::deletePit,
+                highLevelClient()::deletePitAsync
+            );
+            assertTrue(deletePitResponse.getDeletePitResults().get(0).isSuccessful());
+            assertTrue(deletePitResponse.getDeletePitResults().get(0).getPitId().equals(pitResponse.getId()));
+        }
+    }
+
     public void testMultiSearch() throws Exception {
         MultiSearchRequest multiSearchRequest = new MultiSearchRequest();
         SearchRequest searchRequest1 = new SearchRequest("index1");
@@ -800,6 +910,56 @@ public void testMultiSearch() throws Exception {
         assertThat(multiSearchResponse.getResponses()[2].getResponse().getHits().getAt(1).getId(), Matchers.equalTo("6"));
     }
 
+    public void testSearchWithSort() throws Exception {
+        final String indexName = "search_sort";
+        Request createIndex = new Request(HttpPut.METHOD_NAME, "/" + indexName);
+        createIndex.setJsonEntity(
+            "{\n"
+                + "    \"mappings\": {\n"
+                + "        \"properties\" : {\n"
+                + "            \"username\" : {\n"
+                + "                \"type\" : \"keyword\"\n"
+                + "            },\n"
+                + "            \"rating\" : {\n"
+                + "                \"type\" : \"unsigned_long\"\n"
+                + "            }\n"
+                + "        }\n"
+                + "    }"
+                + "}"
+        );
+        client().performRequest(createIndex);
+
+        {
+            Request doc1 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/1");
+            doc1.setJsonEntity("{\"username\":\"bob\", \"rating\": 18446744073709551610}");
+            client().performRequest(doc1);
+            Request doc2 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/2");
+            doc2.setJsonEntity("{\"username\":\"tom\", \"rating\": 10223372036854775807}");
+            client().performRequest(doc2);
+            Request doc3 = new Request(HttpPut.METHOD_NAME, "/" + indexName + "/_doc/3");
+            doc3.setJsonEntity("{\"username\":\"john\"}");
+            client().performRequest(doc3);
+        }
+        client().performRequest(new Request(HttpPost.METHOD_NAME, "/search_sort/_refresh"));
+
+        SearchRequest searchRequest = new SearchRequest("search_sort");
+        searchRequest.source().sort("rating", SortOrder.ASC);
+        SearchResponse searchResponse = execute(searchRequest, highLevelClient()::search, highLevelClient()::searchAsync);
+
+        assertThat(searchResponse.getTook().millis(), Matchers.greaterThanOrEqualTo(0L));
+        assertThat(searchResponse.getHits().getTotalHits().value, Matchers.equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), Matchers.equalTo("2"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), Matchers.equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), Matchers.equalTo("3"));
+
+        assertThat(searchResponse.getHits().getAt(0).getSortValues().length, equalTo(1));
+        assertThat(searchResponse.getHits().getAt(0).getSortValues()[0], equalTo(new BigInteger("10223372036854775807")));
+        assertThat(searchResponse.getHits().getAt(1).getSortValues().length, equalTo(1));
+        assertThat(searchResponse.getHits().getAt(1).getSortValues()[0], equalTo(new BigInteger("18446744073709551610")));
+        assertThat(searchResponse.getHits().getAt(2).getSortValues().length, equalTo(1));
+        assertThat(searchResponse.getHits().getAt(2).getSortValues()[0], equalTo(new BigInteger("18446744073709551615")));
+    }
+
     public void testMultiSearch_withAgg() throws Exception {
         MultiSearchRequest multiSearchRequest = new MultiSearchRequest();
         SearchRequest searchRequest1 = new SearchRequest("index1");
@@ -1040,7 +1200,7 @@ public void testRenderSearchTemplate() throws IOException {
         BytesReference actualSource = searchTemplateResponse.getSource();
         assertNotNull(actualSource);
 
-        assertToXContentEquivalent(expectedSource, actualSource, XContentType.JSON);
+        assertToXContentEquivalent(expectedSource, actualSource, MediaTypeRegistry.JSON);
     }
 
     public void testMultiSearchTemplate() throws Exception {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/SearchPipelineClientIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/SearchPipelineClientIT.java
new file mode 100644
index 0000000000000..9304be7f21899
--- /dev/null
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/SearchPipelineClientIT.java
@@ -0,0 +1,115 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client;
+
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineResponse;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+public class SearchPipelineClientIT extends OpenSearchRestHighLevelClientTestCase {
+
+    public void testPutPipeline() throws IOException {
+        String id = "some_pipeline_id";
+        XContentBuilder pipelineBuilder = buildSearchPipeline();
+        PutSearchPipelineRequest request = new PutSearchPipelineRequest(
+            id,
+            BytesReference.bytes(pipelineBuilder),
+            pipelineBuilder.contentType()
+        );
+        createPipeline(request);
+    }
+
+    private static void createPipeline(PutSearchPipelineRequest request) throws IOException {
+        AcknowledgedResponse response = execute(
+            request,
+            highLevelClient().searchPipeline()::put,
+            highLevelClient().searchPipeline()::putAsync
+        );
+        assertTrue(response.isAcknowledged());
+    }
+
+    public void testGetPipeline() throws IOException {
+        String id = "some_pipeline_id";
+        XContentBuilder pipelineBuilder = buildSearchPipeline();
+        PutSearchPipelineRequest request = new PutSearchPipelineRequest(
+            id,
+            BytesReference.bytes(pipelineBuilder),
+            pipelineBuilder.contentType()
+        );
+        createPipeline(request);
+
+        GetSearchPipelineRequest getRequest = new GetSearchPipelineRequest(id);
+        GetSearchPipelineResponse response = execute(
+            getRequest,
+            highLevelClient().searchPipeline()::get,
+            highLevelClient().searchPipeline()::getAsync
+        );
+        assertTrue(response.isFound());
+        assertEquals(1, response.pipelines().size());
+        assertEquals(id, response.pipelines().get(0).getId());
+    }
+
+    public void testDeletePipeline() throws IOException {
+        String id = "some_pipeline_id";
+        XContentBuilder pipelineBuilder = buildSearchPipeline();
+        PutSearchPipelineRequest request = new PutSearchPipelineRequest(
+            id,
+            BytesReference.bytes(pipelineBuilder),
+            pipelineBuilder.contentType()
+        );
+        createPipeline(request);
+
+        DeleteSearchPipelineRequest deleteRequest = new DeleteSearchPipelineRequest(id);
+        AcknowledgedResponse response = execute(
+            deleteRequest,
+            highLevelClient().searchPipeline()::delete,
+            highLevelClient().searchPipeline()::deleteAsync
+        );
+        assertTrue(response.isAcknowledged());
+    }
+
+    private static XContentBuilder buildSearchPipeline() throws IOException {
+        XContentType xContentType = randomFrom(XContentType.values());
+        XContentBuilder pipelineBuilder = XContentBuilder.builder(xContentType.xContent());
+        return buildSearchPipeline(pipelineBuilder);
+    }
+
+    private static XContentBuilder buildSearchPipeline(XContentBuilder builder) throws IOException {
+        builder.startObject();
+        {
+            builder.field("description", "a pipeline description");
+            builder.startArray("request_processors");
+            {
+                builder.startObject().startObject("filter_query");
+                {
+                    builder.startObject("query");
+                    {
+                        builder.startObject("term");
+                        {
+                            builder.field("field", "value");
+                        }
+                        builder.endObject();
+                    }
+                    builder.endObject();
+                }
+                builder.endObject().endObject();
+            }
+            builder.endArray();
+        }
+        builder.endObject();
+        return builder;
+    }
+}
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotIT.java
index 1d93dae5b2c5b..362a8f10d6a77 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotIT.java
@@ -54,9 +54,9 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.repositories.fs.FsRepository;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.snapshots.RestoreInfo;
 import org.opensearch.snapshots.SnapshotInfo;
 
@@ -76,7 +76,7 @@ public class SnapshotIT extends OpenSearchRestHighLevelClientTestCase {
 
     private AcknowledgedResponse createTestRepository(String repository, String type, String settings) throws IOException {
         PutRepositoryRequest request = new PutRepositoryRequest(repository);
-        request.settings(settings, XContentType.JSON);
+        request.settings(settings, MediaTypeRegistry.JSON);
         request.type(type);
         return execute(request, highLevelClient().snapshot()::createRepository, highLevelClient().snapshot()::createRepositoryAsync);
     }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotRequestConvertersTests.java
index f18679127bf2b..93ffd7cade7c3 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/SnapshotRequestConvertersTests.java
@@ -48,7 +48,7 @@
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -263,7 +263,7 @@ public void testRestoreSnapshot() throws IOException {
 
         if (randomBoolean()) {
             String timeout = randomTimeValue();
-            restoreSnapshotRequest.masterNodeTimeout(timeout);
+            restoreSnapshotRequest.clusterManagerNodeTimeout(timeout);
             expectedParams.put("master_timeout", timeout);
         }
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/StoredScriptsIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/StoredScriptsIT.java
index b3898fe0b9566..4d792e53c6064 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/StoredScriptsIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/StoredScriptsIT.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptRequest;
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptResponse;
 import org.opensearch.action.admin.cluster.storedscripts.PutStoredScriptRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.script.Script;
 import org.opensearch.script.StoredScriptSource;
 
@@ -58,14 +58,20 @@ public void testGetStoredScript() throws Exception {
         final StoredScriptSource scriptSource = new StoredScriptSource(
             "painless",
             "Math.log(_score * 2) + params.my_modifier",
-            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
         );
 
-        PutStoredScriptRequest request = new PutStoredScriptRequest(id, "score", new BytesArray("{}"), XContentType.JSON, scriptSource);
+        PutStoredScriptRequest request = new PutStoredScriptRequest(
+            id,
+            "score",
+            new BytesArray("{}"),
+            MediaTypeRegistry.JSON,
+            scriptSource
+        );
         assertAcked(execute(request, highLevelClient()::putScript, highLevelClient()::putScriptAsync));
 
         GetStoredScriptRequest getRequest = new GetStoredScriptRequest("calculate-score");
-        getRequest.masterNodeTimeout("50s");
+        getRequest.clusterManagerNodeTimeout("50s");
 
         GetStoredScriptResponse getResponse = execute(getRequest, highLevelClient()::getScript, highLevelClient()::getScriptAsync);
 
@@ -76,14 +82,20 @@ public void testDeleteStoredScript() throws Exception {
         final StoredScriptSource scriptSource = new StoredScriptSource(
             "painless",
             "Math.log(_score * 2) + params.my_modifier",
-            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
         );
 
-        PutStoredScriptRequest request = new PutStoredScriptRequest(id, "score", new BytesArray("{}"), XContentType.JSON, scriptSource);
+        PutStoredScriptRequest request = new PutStoredScriptRequest(
+            id,
+            "score",
+            new BytesArray("{}"),
+            MediaTypeRegistry.JSON,
+            scriptSource
+        );
         assertAcked(execute(request, highLevelClient()::putScript, highLevelClient()::putScriptAsync));
 
         DeleteStoredScriptRequest deleteRequest = new DeleteStoredScriptRequest(id);
-        deleteRequest.masterNodeTimeout("50s");
+        deleteRequest.clusterManagerNodeTimeout("50s");
         deleteRequest.timeout("50s");
         assertAcked(execute(deleteRequest, highLevelClient()::deleteScript, highLevelClient()::deleteScriptAsync));
 
@@ -100,10 +112,16 @@ public void testPutScript() throws Exception {
         final StoredScriptSource scriptSource = new StoredScriptSource(
             "painless",
             "Math.log(_score * 2) + params.my_modifier",
-            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
         );
 
-        PutStoredScriptRequest request = new PutStoredScriptRequest(id, "score", new BytesArray("{}"), XContentType.JSON, scriptSource);
+        PutStoredScriptRequest request = new PutStoredScriptRequest(
+            id,
+            "score",
+            new BytesArray("{}"),
+            MediaTypeRegistry.JSON,
+            scriptSource
+        );
         assertAcked(execute(request, highLevelClient()::putScript, highLevelClient()::putScriptAsync));
 
         Map<String, Object> script = getAsMap("/_scripts/" + id);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/TasksIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/TasksIT.java
index d987e786fff76..c5a16ec32e686 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/TasksIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/TasksIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.index.reindex.ReindexRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.TaskGroup;
@@ -46,8 +45,9 @@
 import org.opensearch.client.tasks.TaskId;
 import org.opensearch.client.tasks.TaskSubmissionResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.reindex.ReindexRequest;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -94,9 +94,9 @@ public void testGetValidTask() throws Exception {
         createIndex(sourceIndex, settings);
         createIndex(destinationIndex, settings);
         BulkRequest bulkRequest = new BulkRequest().add(
-            new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON)
+            new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON)
         )
-            .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
+            .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), MediaTypeRegistry.JSON))
             .setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         assertEquals(RestStatus.OK, highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status());
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/TasksRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/TasksRequestConvertersTests.java
index 64fec3c8fb810..e67babc2b3ca2 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/TasksRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/TasksRequestConvertersTests.java
@@ -36,7 +36,7 @@
 import org.apache.http.client.methods.HttpPost;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 import org.opensearch.client.tasks.CancelTasksRequest;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashMap;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/TimedRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/TimedRequestTests.java
index 3026472bb8e53..a630f4f5c1489 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/TimedRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/TimedRequestTests.java
@@ -41,17 +41,17 @@ public void testDefaults() {
         TimedRequest timedRequest = new TimedRequest() {
         };
         assertEquals(timedRequest.timeout(), TimedRequest.DEFAULT_ACK_TIMEOUT);
-        assertEquals(timedRequest.masterNodeTimeout(), TimedRequest.DEFAULT_MASTER_NODE_TIMEOUT);
+        assertEquals(timedRequest.clusterManagerNodeTimeout(), TimedRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT);
     }
 
     public void testNonDefaults() {
         TimedRequest timedRequest = new TimedRequest() {
         };
         TimeValue timeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
-        TimeValue masterTimeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
+        TimeValue clusterManagerTimeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
         timedRequest.setTimeout(timeout);
-        timedRequest.setMasterTimeout(masterTimeout);
+        timedRequest.setClusterManagerTimeout(clusterManagerTimeout);
         assertEquals(timedRequest.timeout(), timeout);
-        assertEquals(timedRequest.masterNodeTimeout(), masterTimeout);
+        assertEquals(timedRequest.clusterManagerNodeTimeout(), clusterManagerTimeout);
     }
 }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/UpdateByQueryIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/UpdateByQueryIT.java
index d73fa2bd0aa80..ef7b7d5a39b6f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/UpdateByQueryIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/UpdateByQueryIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkRequest;
@@ -41,15 +40,16 @@
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.client.tasks.TaskSubmissionResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.reindex.BulkByScrollResponse;
 import org.opensearch.index.reindex.UpdateByQueryAction;
 import org.opensearch.index.reindex.UpdateByQueryRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.Script;
 import org.opensearch.tasks.RawTaskStatus;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -76,9 +76,9 @@ public void testUpdateByQuery() throws Exception {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), XContentType.JSON)
+                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), XContentType.JSON))
+                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), MediaTypeRegistry.JSON))
                         .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
@@ -197,10 +197,10 @@ public void testUpdateByQueryTask() throws Exception {
                 RestStatus.OK,
                 highLevelClient().bulk(
                     new BulkRequest().add(
-                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), XContentType.JSON)
+                        new IndexRequest(sourceIndex).id("1").source(Collections.singletonMap("foo", 1), MediaTypeRegistry.JSON)
                     )
-                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), XContentType.JSON))
-                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), XContentType.JSON))
+                        .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo", 2), MediaTypeRegistry.JSON))
+                        .add(new IndexRequest(sourceIndex).id("3").source(Collections.singletonMap("foo", 3), MediaTypeRegistry.JSON))
                         .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE),
                     RequestOptions.DEFAULT
                 ).status()
@@ -230,9 +230,9 @@ public void testUpdateByQueryConflict() throws IOException {
         final Settings settings = Settings.builder().put("number_of_shards", 1).put("number_of_replicas", 0).build();
         createIndex(index, settings);
         final BulkRequest bulkRequest = new BulkRequest().add(
-            new IndexRequest(index).id("1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON)
+            new IndexRequest(index).id("1").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON)
         )
-            .add(new IndexRequest(index).id("2").source(Collections.singletonMap("foo", "bar"), XContentType.JSON))
+            .add(new IndexRequest(index).id("2").source(Collections.singletonMap("foo", "bar"), MediaTypeRegistry.JSON))
             .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
         assertThat(highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status(), equalTo(RestStatus.OK));
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/cluster/RemoteInfoResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/cluster/RemoteInfoResponseTests.java
index a6ebec8197698..201a8ee1e60ac 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/cluster/RemoteInfoResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/cluster/RemoteInfoResponseTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.client.AbstractResponseTestCase;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.transport.ProxyConnectionStrategy;
 import org.opensearch.transport.RemoteConnectionInfo;
 import org.opensearch.transport.SniffConnectionStrategy;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/AcknowledgedResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/AcknowledgedResponseTests.java
index a517e37dc8764..e184df7ad013c 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/AcknowledgedResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/AcknowledgedResponseTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.client.core;
 
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/BroadcastResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/BroadcastResponseTests.java
index b608e6945a4b3..de2af42cb900f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/BroadcastResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/BroadcastResponseTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.seqno.RetentionLeaseNotFoundException;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/CountRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/CountRequestTests.java
index a973f8352a08c..d5e739789829d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/CountRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/CountRequestTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.client.AbstractRequestTestCase;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.ArrayUtils;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/CountResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/CountResponseTests.java
index 3b9b91bd93c1d..946ebc1089580 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/CountResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/CountResponseTests.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.action.RestActions;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/GetSourceResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/GetSourceResponseTests.java
index 6f26fed2d0458..0c2b269c7e78d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/GetSourceResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/GetSourceResponseTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.client.core;
 
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -61,7 +61,7 @@ static class SourceOnlyResponse implements ToXContentObject {
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             // this implementation copied from RestGetSourceAction.RestGetSourceResponseListener::buildResponse
             try (InputStream stream = source.streamInput()) {
-                builder.rawValue(stream, XContentHelper.xContentType(source));
+                builder.rawValue(stream, MediaTypeRegistry.xContentType(source));
             }
             return builder;
         }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/MainResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/MainResponseTests.java
index cabb125a739b7..99f28ae337dc5 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/MainResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/MainResponseTests.java
@@ -37,8 +37,8 @@
 import org.opensearch.Version;
 import org.opensearch.client.AbstractResponseTestCase;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/MultiTermVectorsResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/MultiTermVectorsResponseTests.java
index c7f1fa0982afa..20835cacfd356 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/MultiTermVectorsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/MultiTermVectorsResponseTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/ShardsAcknowledgedResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/ShardsAcknowledgedResponseTests.java
index 5e2c275708537..e426e7fbdbf5f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/ShardsAcknowledgedResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/ShardsAcknowledgedResponseTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/TermVectorsResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/TermVectorsResponseTests.java
index 33b82c10d8873..5b6b96fd9144f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/TermVectorsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/TermVectorsResponseTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.client.core;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
-import java.util.ArrayList;
-import java.util.List;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.List;
 
 import static org.opensearch.test.AbstractXContentTestCase.xContentTester;
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/core/tasks/GetTaskResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/core/tasks/GetTaskResponseTests.java
index 403e295303784..060caeddd9826 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/core/tasks/GetTaskResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/core/tasks/GetTaskResponseTests.java
@@ -34,17 +34,21 @@
 
 import org.opensearch.client.Requests;
 import org.opensearch.client.tasks.GetTaskResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceStats;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.core.tasks.resourcetracker.TaskThreadUsage;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.RawTaskStatus;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 
 import static org.opensearch.test.AbstractXContentTestCase.xContentTester;
@@ -57,7 +61,7 @@ public void testFromXContent() throws IOException {
         )
             .assertEqualsConsumer(this::assertEqualInstances)
             .assertToXContentEquivalence(true)
-            .randomFieldsExcludeFilter(field -> field.endsWith("headers") || field.endsWith("status"))
+            .randomFieldsExcludeFilter(field -> field.endsWith("headers") || field.endsWith("status") || field.contains("resource_stats"))
             .test();
     }
 
@@ -92,6 +96,10 @@ static TaskInfo randomTaskInfo() {
         boolean cancellable = randomBoolean();
         boolean cancelled = cancellable == true ? randomBoolean() : false;
         TaskId parentTaskId = randomBoolean() ? TaskId.EMPTY_TASK_ID : randomTaskId();
+        Long cancellationStartTime = null;
+        if (cancelled) {
+            cancellationStartTime = randomNonNegativeLong();
+        }
         Map<String, String> headers = randomBoolean()
             ? Collections.emptyMap()
             : Collections.singletonMap(randomAlphaOfLength(5), randomAlphaOfLength(5));
@@ -106,7 +114,9 @@ static TaskInfo randomTaskInfo() {
             cancellable,
             cancelled,
             parentTaskId,
-            headers
+            headers,
+            randomResourceStats(),
+            cancellationStartTime
         );
     }
 
@@ -127,4 +137,14 @@ private static RawTaskStatus randomRawTaskStatus() {
             throw new IllegalStateException(e);
         }
     }
+
+    private static TaskResourceStats randomResourceStats() {
+        return randomBoolean() ? null : new TaskResourceStats(new HashMap<>() {
+            {
+                for (int i = 0; i < randomInt(5); i++) {
+                    put(randomAlphaOfLength(5), new TaskResourceUsage(randomNonNegativeLong(), randomNonNegativeLong()));
+                }
+            }
+        }, new TaskThreadUsage(randomInt(10), randomInt(10)));
+    }
 }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/CRUDDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/CRUDDocumentationIT.java
index 959c5a827f143..b2cfe5ff9f55c 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/CRUDDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/CRUDDocumentationIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.http.HttpHost;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.LatchedActionListener;
@@ -74,16 +73,19 @@
 import org.opensearch.client.core.TermVectorsResponse;
 import org.opensearch.client.indices.CreateIndexRequest;
 import org.opensearch.client.indices.CreateIndexResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.query.MatchAllQueryBuilder;
@@ -94,11 +96,9 @@
 import org.opensearch.index.reindex.RemoteInfo;
 import org.opensearch.index.reindex.ScrollableHitSource;
 import org.opensearch.index.reindex.UpdateByQueryRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
-import org.opensearch.tasks.TaskId;
 
 import java.util.Collections;
 import java.util.Date;
@@ -173,7 +173,7 @@ public void testIndex() throws Exception {
                     "\"postDate\":\"2013-01-30\"," +
                     "\"message\":\"trying out OpenSearch\"" +
                     "}";
-            request.source(jsonString, XContentType.JSON); // <3>
+            request.source(jsonString, MediaTypeRegistry.JSON); // <3>
             //end::index-request-string
 
             // tag::index-execute
@@ -298,15 +298,14 @@ public void testUpdate() throws Exception {
 
             Request request = new Request("POST", "/_scripts/increment-field");
             request.setJsonEntity(
-                Strings.toString(
-                    JsonXContent.contentBuilder()
-                        .startObject()
-                        .startObject("script")
-                        .field("lang", "painless")
-                        .field("source", "ctx._source.field += params.count")
-                        .endObject()
-                        .endObject()
-                )
+                JsonXContent.contentBuilder()
+                    .startObject()
+                    .startObject("script")
+                    .field("lang", "painless")
+                    .field("source", "ctx._source.field += params.count")
+                    .endObject()
+                    .endObject()
+                    .toString()
             );
             Response response = client().performRequest(request);
             assertEquals(RestStatus.OK.getStatus(), response.getStatusLine().getStatusCode());
@@ -381,7 +380,7 @@ public void testUpdate() throws Exception {
                     "\"updated\":\"2017-01-01\"," +
                     "\"reason\":\"daily update\"" +
                     "}";
-            request.doc(jsonString, XContentType.JSON); // <1>
+            request.doc(jsonString, MediaTypeRegistry.JSON); // <1>
             //end::update-request-with-doc-as-string
             request.fetchSource(true);
             // tag::update-execute
@@ -525,7 +524,7 @@ public void testUpdate() throws Exception {
             // end::update-request-detect-noop
             // tag::update-request-upsert
             String jsonString = "{\"created\":\"2017-01-01\"}";
-            request.upsert(jsonString, XContentType.JSON);  // <1>
+            request.upsert(jsonString, MediaTypeRegistry.JSON);  // <1>
             // end::update-request-upsert
             // tag::update-request-scripted-upsert
             request.scriptedUpsert(true); // <1>
@@ -699,11 +698,11 @@ public void testBulk() throws Exception {
             // tag::bulk-request
             BulkRequest request = new BulkRequest(); // <1>
             request.add(new IndexRequest("posts").id("1")  // <2>
-                    .source(XContentType.JSON,"field", "foo"));
+                    .source(MediaTypeRegistry.JSON,"field", "foo"));
             request.add(new IndexRequest("posts").id("2")  // <3>
-                    .source(XContentType.JSON,"field", "bar"));
+                    .source(MediaTypeRegistry.JSON,"field", "bar"));
             request.add(new IndexRequest("posts").id("3")  // <4>
-                    .source(XContentType.JSON,"field", "baz"));
+                    .source(MediaTypeRegistry.JSON,"field", "baz"));
             // end::bulk-request
             // tag::bulk-execute
             BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
@@ -716,9 +715,9 @@ public void testBulk() throws Exception {
             BulkRequest request = new BulkRequest();
             request.add(new DeleteRequest("posts", "3")); // <1>
             request.add(new UpdateRequest("posts", "2") // <2>
-                    .doc(XContentType.JSON,"other", "test"));
+                    .doc(MediaTypeRegistry.JSON,"other", "test"));
             request.add(new IndexRequest("posts").id("4")  // <3>
-                    .source(XContentType.JSON,"field", "baz"));
+                    .source(MediaTypeRegistry.JSON,"field", "baz"));
             // end::bulk-request-with-mixed-operations
             BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
             assertSame(RestStatus.OK, bulkResponse.status());
@@ -1581,13 +1580,13 @@ public void afterBulk(long executionId, BulkRequest request,
 
             // tag::bulk-processor-add
             IndexRequest one = new IndexRequest("posts").id("1")
-                    .source(XContentType.JSON, "title",
+                    .source(MediaTypeRegistry.JSON, "title",
                             "In which order are my OpenSearch queries executed?");
             IndexRequest two = new IndexRequest("posts").id("2")
-                    .source(XContentType.JSON, "title",
+                    .source(MediaTypeRegistry.JSON, "title",
                             "Current status and upcoming changes in OpenSearch");
             IndexRequest three = new IndexRequest("posts").id("3")
-                    .source(XContentType.JSON, "title",
+                    .source(MediaTypeRegistry.JSON, "title",
                             "The Future of Federated Search in OpenSearch");
 
             bulkProcessor.add(one);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/ClusterClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/ClusterClientDocumentationIT.java
index 7762813aa53ce..17ea5b273d2a2 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/ClusterClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/ClusterClientDocumentationIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client.documentation;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -63,11 +62,12 @@
 import org.opensearch.common.Priority;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -138,7 +138,7 @@ public void testClusterPutSettings() throws IOException {
             // tag::put-settings-settings-source
             request.transientSettings(
                     "{\"indices.recovery.max_bytes_per_sec\": \"10b\"}"
-                    , XContentType.JSON); // <1>
+                    , MediaTypeRegistry.JSON); // <1>
             // end::put-settings-settings-source
         }
 
@@ -147,8 +147,8 @@ public void testClusterPutSettings() throws IOException {
         request.timeout("2m"); // <2>
         // end::put-settings-request-timeout
         // tag::put-settings-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::put-settings-request-masterTimeout
 
         // tag::put-settings-execute
@@ -222,8 +222,8 @@ public void testClusterGetSettings() throws IOException {
         // end::get-settings-request-local
 
         // tag::get-settings-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::get-settings-request-masterTimeout
 
         // tag::get-settings-execute
@@ -299,8 +299,8 @@ public void testClusterHealth() throws IOException {
         // end::health-request-timeout
 
         // tag::health-request-master-timeout
-        request.masterNodeTimeout(TimeValue.timeValueSeconds(20)); // <1>
-        request.masterNodeTimeout("20s"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueSeconds(20)); // <1>
+        request.clusterManagerNodeTimeout("20s"); // <2>
         // end::health-request-master-timeout
 
         // tag::health-request-wait-status
@@ -515,8 +515,8 @@ public void testGetComponentTemplates() throws Exception {
         // end::get-component-templates-request
 
         // tag::get-component-templates-request-masterTimeout
-        request.setMasterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.setMasterNodeTimeout("1m"); // <2>
+        request.setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.setClusterManagerNodeTimeout("1m"); // <2>
         // end::get-component-templates-request-masterTimeout
 
         // tag::get-component-templates-execute
@@ -603,7 +603,7 @@ public void testPutComponentTemplate() throws Exception {
             // end::put-component-template-request-create
 
             // tag::put-component-template-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::put-component-template-request-masterTimeout
 
             request.create(false); // make test happy
@@ -670,7 +670,7 @@ public void testDeleteComponentTemplate() throws Exception {
         // end::delete-component-template-request
 
         // tag::delete-component-template-request-masterTimeout
-        deleteRequest.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        deleteRequest.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
         // end::delete-component-template-request-masterTimeout
 
         // tag::delete-component-template-execute
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IndicesClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IndicesClientDocumentationIT.java
index 3fbe7f63b09a2..abb2d75aea751 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IndicesClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IndicesClientDocumentationIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.client.documentation;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
@@ -61,11 +60,10 @@
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryRequest;
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryResponse;
 import org.opensearch.action.support.ActiveShardCount;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.client.OpenSearchRestHighLevelClientTestCase;
 import org.opensearch.client.GetAliasesResponse;
+import org.opensearch.client.OpenSearchRestHighLevelClientTestCase;
 import org.opensearch.client.RequestOptions;
 import org.opensearch.client.RestHighLevelClient;
 import org.opensearch.client.indices.AnalyzeRequest;
@@ -77,21 +75,21 @@
 import org.opensearch.client.indices.DeleteAliasRequest;
 import org.opensearch.client.indices.DeleteComposableIndexTemplateRequest;
 import org.opensearch.client.indices.DetailAnalyzeResponse;
+import org.opensearch.client.indices.GetComposableIndexTemplateRequest;
+import org.opensearch.client.indices.GetComposableIndexTemplatesResponse;
 import org.opensearch.client.indices.GetFieldMappingsRequest;
 import org.opensearch.client.indices.GetFieldMappingsResponse;
 import org.opensearch.client.indices.GetIndexRequest;
 import org.opensearch.client.indices.GetIndexResponse;
-import org.opensearch.client.indices.GetComposableIndexTemplateRequest;
 import org.opensearch.client.indices.GetIndexTemplatesRequest;
 import org.opensearch.client.indices.GetIndexTemplatesResponse;
-import org.opensearch.client.indices.GetComposableIndexTemplatesResponse;
 import org.opensearch.client.indices.GetMappingsRequest;
 import org.opensearch.client.indices.GetMappingsResponse;
 import org.opensearch.client.indices.IndexTemplateMetadata;
 import org.opensearch.client.indices.IndexTemplatesExistRequest;
 import org.opensearch.client.indices.PutComponentTemplateRequest;
-import org.opensearch.client.indices.PutIndexTemplateRequest;
 import org.opensearch.client.indices.PutComposableIndexTemplateRequest;
+import org.opensearch.client.indices.PutIndexTemplateRequest;
 import org.opensearch.client.indices.PutMappingRequest;
 import org.opensearch.client.indices.SimulateIndexTemplateRequest;
 import org.opensearch.client.indices.SimulateIndexTemplateResponse;
@@ -104,16 +102,18 @@
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -235,8 +235,8 @@ public void testDeleteIndex() throws IOException {
             request.timeout("2m"); // <2>
             // end::delete-index-request-timeout
             // tag::delete-index-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::delete-index-request-masterTimeout
             // tag::delete-index-request-indicesOptions
             request.indicesOptions(IndicesOptions.lenientExpandOpen()); // <1>
@@ -329,7 +329,7 @@ public void testCreateIndex() throws IOException {
                         "    }\n" +
                         "  }\n" +
                         "}", // <2>
-                        XContentType.JSON);
+                        MediaTypeRegistry.JSON);
                 // end::create-index-request-mappings
                 CreateIndexResponse createIndexResponse = client.indices().create(request, RequestOptions.DEFAULT);
                 assertTrue(createIndexResponse.isAcknowledged());
@@ -381,7 +381,7 @@ public void testCreateIndex() throws IOException {
             request.setTimeout(TimeValue.timeValueMinutes(2)); // <1>
             // end::create-index-request-timeout
             // tag::create-index-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::create-index-request-masterTimeout
             // tag::create-index-request-waitForActiveShards
             request.waitForActiveShards(ActiveShardCount.from(2)); // <1>
@@ -407,7 +407,7 @@ public void testCreateIndex() throws IOException {
                     "    \"aliases\" : {\n" +
                     "        \"twitter_alias\" : {}\n" +
                     "    }\n" +
-                    "}", XContentType.JSON); // <1>
+                    "}", MediaTypeRegistry.JSON); // <1>
             // end::create-index-whole-source
 
             // tag::create-index-execute
@@ -480,7 +480,7 @@ public void testPutMapping() throws IOException {
                     "    }\n" +
                     "  }\n" +
                     "}", // <1>
-                    XContentType.JSON);
+                    MediaTypeRegistry.JSON);
                 // end::put-mapping-request-source
                 AcknowledgedResponse putMappingResponse = client.indices().putMapping(request, RequestOptions.DEFAULT);
                 assertTrue(putMappingResponse.isAcknowledged());
@@ -526,7 +526,7 @@ public void testPutMapping() throws IOException {
             // end::put-mapping-request-timeout
 
             // tag::put-mapping-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::put-mapping-request-masterTimeout
 
             // tag::put-mapping-execute
@@ -585,7 +585,7 @@ public void testGetMapping() throws IOException {
             CreateIndexResponse createIndexResponse = client.indices().create(new CreateIndexRequest("twitter"), RequestOptions.DEFAULT);
             assertTrue(createIndexResponse.isAcknowledged());
             PutMappingRequest request = new PutMappingRequest("twitter");
-            request.source("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", XContentType.JSON);
+            request.source("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", MediaTypeRegistry.JSON);
             AcknowledgedResponse putMappingResponse = client.indices().putMapping(request, RequestOptions.DEFAULT);
             assertTrue(putMappingResponse.isAcknowledged());
         }
@@ -597,7 +597,7 @@ public void testGetMapping() throws IOException {
             // end::get-mappings-request
 
             // tag::get-mappings-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::get-mappings-request-masterTimeout
 
             // tag::get-mappings-request-indicesOptions
@@ -631,7 +631,7 @@ public void testGetMappingAsync() throws Exception {
             CreateIndexResponse createIndexResponse = client.indices().create(new CreateIndexRequest("twitter"), RequestOptions.DEFAULT);
             assertTrue(createIndexResponse.isAcknowledged());
             PutMappingRequest request = new PutMappingRequest("twitter");
-            request.source("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", XContentType.JSON);
+            request.source("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", MediaTypeRegistry.JSON);
             AcknowledgedResponse putMappingResponse = client.indices().putMapping(request, RequestOptions.DEFAULT);
             assertTrue(putMappingResponse.isAcknowledged());
         }
@@ -703,7 +703,7 @@ public void testGetFieldMapping() throws IOException, InterruptedException {
                     + "    }\n"
                     + "  }\n"
                     + "}", // <1>
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             );
             AcknowledgedResponse putMappingResponse = client.indices().putMapping(request, RequestOptions.DEFAULT);
             assertTrue(putMappingResponse.isAcknowledged());
@@ -801,8 +801,8 @@ public void testOpenIndex() throws Exception {
             request.timeout("2m"); // <2>
             // end::open-index-request-timeout
             // tag::open-index-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::open-index-request-masterTimeout
             // tag::open-index-request-waitForActiveShards
             request.waitForActiveShards(2); // <1>
@@ -1127,7 +1127,8 @@ public void testGetIndex() throws Exception {
         {
             Settings settings = Settings.builder().put("number_of_shards", 3).build();
             String mappings = "{\"properties\":{\"field-1\":{\"type\":\"integer\"}}}";
-            CreateIndexRequest createIndexRequest = new CreateIndexRequest("index").settings(settings).mapping(mappings, XContentType.JSON);
+            CreateIndexRequest createIndexRequest = new CreateIndexRequest("index").settings(settings)
+                .mapping(mappings, MediaTypeRegistry.JSON);
             CreateIndexResponse createIndexResponse = client.indices().create(createIndexRequest, RequestOptions.DEFAULT);
             assertTrue(createIndexResponse.isAcknowledged());
         }
@@ -1374,7 +1375,7 @@ public void testCloseIndex() throws Exception {
             request.setTimeout(TimeValue.timeValueMinutes(2)); // <1>
             // end::close-index-request-timeout
             // tag::close-index-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::close-index-request-masterTimeout
 
             // tag::close-index-request-indicesOptions
@@ -1530,8 +1531,8 @@ public void testUpdateAliases() throws Exception {
             request.timeout("2m"); // <2>
             // end::update-aliases-request-timeout
             // tag::update-aliases-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::update-aliases-request-masterTimeout
 
             // tag::update-aliases-execute
@@ -1600,8 +1601,8 @@ public void testShrinkIndex() throws Exception {
         request.timeout("2m"); // <2>
         // end::shrink-index-request-timeout
         // tag::shrink-index-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::shrink-index-request-masterTimeout
         // tag::shrink-index-request-waitForActiveShards
         request.setWaitForActiveShards(2); // <1>
@@ -1677,8 +1678,8 @@ public void testSplitIndex() throws Exception {
         request.timeout("2m"); // <2>
         // end::split-index-request-timeout
         // tag::split-index-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::split-index-request-masterTimeout
         // tag::split-index-request-waitForActiveShards
         request.setWaitForActiveShards(2); // <1>
@@ -1746,8 +1747,8 @@ public void testCloneIndex() throws Exception {
         request.timeout("2m"); // <2>
         // end::clone-index-request-timeout
         // tag::clone-index-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::clone-index-request-masterTimeout
         // tag::clone-index-request-waitForActiveShards
         request.setWaitForActiveShards(2); // <1>
@@ -1815,7 +1816,7 @@ public void testRolloverIndex() throws Exception {
         request.setTimeout(TimeValue.timeValueMinutes(2)); // <1>
         // end::rollover-index-request-timeout
         // tag::rollover-index-request-masterTimeout
-        request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
         // end::rollover-index-request-masterTimeout
         // tag::rollover-index-request-dryRun
         request.dryRun(true); // <1>
@@ -1830,7 +1831,7 @@ public void testRolloverIndex() throws Exception {
         // end::rollover-index-request-settings
         // tag::rollover-index-request-mapping
         String mappings = "{\"properties\":{\"field-1\":{\"type\":\"keyword\"}}}";
-        request.getCreateIndexRequest().mapping(mappings, XContentType.JSON); // <1>
+        request.getCreateIndexRequest().mapping(mappings, MediaTypeRegistry.JSON); // <1>
         // end::rollover-index-request-mapping
         // tag::rollover-index-request-alias
         request.getCreateIndexRequest().alias(new Alias("another_alias")); // <1>
@@ -2009,7 +2010,7 @@ public void testIndexPutSettings() throws Exception {
             // tag::indices-put-settings-settings-source
             request.settings(
                     "{\"index.number_of_replicas\": \"2\"}"
-                    , XContentType.JSON); // <1>
+                    , MediaTypeRegistry.JSON); // <1>
             // end::indices-put-settings-settings-source
         }
 
@@ -2021,8 +2022,8 @@ public void testIndexPutSettings() throws Exception {
         request.timeout("2m"); // <2>
         // end::indices-put-settings-request-timeout
         // tag::indices-put-settings-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::indices-put-settings-request-masterTimeout
         // tag::indices-put-settings-request-indicesOptions
         request.indicesOptions(IndicesOptions.lenientExpandOpen()); // <1>
@@ -2090,7 +2091,7 @@ public void testPutTemplate() throws Exception {
                     "    }\n" +
                     "  }\n" +
                     "}",
-                XContentType.JSON);
+                MediaTypeRegistry.JSON);
             // end::put-template-request-mappings-json
             assertTrue(client.indices().putTemplate(request, RequestOptions.DEFAULT).isAcknowledged());
         }
@@ -2165,7 +2166,7 @@ public void testPutTemplate() throws Exception {
             "    \"alias-1\": {},\n" +
             "    \"{index}-alias\": {}\n" +
             "  }\n" +
-            "}", XContentType.JSON); // <1>
+            "}", MediaTypeRegistry.JSON); // <1>
         // end::put-template-whole-source
 
         // tag::put-template-request-create
@@ -2173,8 +2174,8 @@ public void testPutTemplate() throws Exception {
         // end::put-template-request-create
 
         // tag::put-template-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::put-template-request-masterTimeout
 
         request.create(false); // make test happy
@@ -2220,7 +2221,7 @@ public void testGetTemplates() throws Exception {
             PutIndexTemplateRequest putRequest = new PutIndexTemplateRequest("my-template");
             putRequest.patterns(Arrays.asList("pattern-1", "log-*"));
             putRequest.settings(Settings.builder().put("index.number_of_shards", 3).put("index.number_of_replicas", 1));
-            putRequest.mapping("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", XContentType.JSON);
+            putRequest.mapping("{ \"properties\": { \"message\": { \"type\": \"text\" } } }", MediaTypeRegistry.JSON);
             assertTrue(client.indices().putTemplate(putRequest, RequestOptions.DEFAULT).isAcknowledged());
         }
 
@@ -2231,8 +2232,8 @@ public void testGetTemplates() throws Exception {
         // end::get-templates-request
 
         // tag::get-templates-request-masterTimeout
-        request.setMasterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.setMasterNodeTimeout("1m"); // <2>
+        request.setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.setClusterManagerNodeTimeout("1m"); // <2>
         // end::get-templates-request-masterTimeout
 
         // tag::get-templates-execute
@@ -2291,8 +2292,8 @@ public void testGetIndexTemplatesV2() throws Exception {
         // end::get-index-templates-v2-request
 
         // tag::get-index-templates-v2-request-masterTimeout
-        request.setMasterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.setMasterNodeTimeout("1m"); // <2>
+        request.setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.setClusterManagerNodeTimeout("1m"); // <2>
         // end::get-index-templates-v2-request-masterTimeout
 
         // tag::get-index-templates-v2-execute
@@ -2450,7 +2451,7 @@ public void testPutIndexTemplateV2() throws Exception {
             // end::put-index-template-v2-request-create
 
             // tag::put-index-template-v2-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::put-index-template-v2-request-masterTimeout
 
             request.create(false); // make test happy
@@ -2511,7 +2512,7 @@ public void testDeleteIndexTemplateV2() throws Exception {
         // end::delete-index-template-v2-request
 
         // tag::delete-index-template-v2-request-masterTimeout
-        deleteRequest.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        deleteRequest.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
         // end::delete-index-template-v2-request-masterTimeout
 
         // tag::delete-index-template-v2-execute
@@ -2644,8 +2645,8 @@ public void testTemplatesExist() throws Exception {
 
             // tag::templates-exist-request-optionals
             request.setLocal(true); // <1>
-            request.setMasterNodeTimeout(TimeValue.timeValueMinutes(1)); // <2>
-            request.setMasterNodeTimeout("1m"); // <3>
+            request.setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <2>
+            request.setClusterManagerNodeTimeout("1m"); // <3>
             // end::templates-exist-request-optionals
 
             // tag::templates-exist-execute
@@ -2897,8 +2898,8 @@ public void testDeleteTemplate() throws Exception {
         // end::delete-template-request
 
         // tag::delete-template-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::delete-template-request-masterTimeout
 
         // tag::delete-template-execute
@@ -2973,7 +2974,7 @@ public void testDeleteAlias() throws Exception {
             request.setTimeout(TimeValue.timeValueMinutes(2)); // <1>
             // end::delete-alias-request-timeout
             // tag::delete-alias-request-masterTimeout
-            request.setMasterTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.setClusterManagerTimeout(TimeValue.timeValueMinutes(1)); // <1>
             // end::delete-alias-request-masterTimeout
 
             // tag::delete-alias-execute
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IngestClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IngestClientDocumentationIT.java
index a6157f2903103..d14759065b5eb 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IngestClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/IngestClientDocumentationIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client.documentation;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.ingest.DeletePipelineRequest;
 import org.opensearch.action.ingest.GetPipelineRequest;
@@ -48,9 +47,10 @@
 import org.opensearch.client.OpenSearchRestHighLevelClientTestCase;
 import org.opensearch.client.RequestOptions;
 import org.opensearch.client.RestHighLevelClient;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.ingest.PipelineConfiguration;
 
 import java.io.IOException;
@@ -91,7 +91,7 @@ public void testPutPipeline() throws IOException {
             PutPipelineRequest request = new PutPipelineRequest(
                 "my-pipeline-id", // <1>
                 new BytesArray(source.getBytes(StandardCharsets.UTF_8)), // <2>
-                XContentType.JSON // <3>
+                MediaTypeRegistry.JSON // <3>
             );
             // end::put-pipeline-request
 
@@ -101,8 +101,8 @@ public void testPutPipeline() throws IOException {
             // end::put-pipeline-request-timeout
 
             // tag::put-pipeline-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::put-pipeline-request-masterTimeout
 
             // tag::put-pipeline-execute
@@ -125,7 +125,7 @@ public void testPutPipelineAsync() throws Exception {
             PutPipelineRequest request = new PutPipelineRequest(
                 "my-pipeline-id",
                 new BytesArray(source.getBytes(StandardCharsets.UTF_8)),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             );
 
             // tag::put-pipeline-execute-listener
@@ -169,8 +169,8 @@ public void testGetPipeline() throws IOException {
             // end::get-pipeline-request
 
             // tag::get-pipeline-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::get-pipeline-request-masterTimeout
 
             // tag::get-pipeline-execute
@@ -244,8 +244,8 @@ public void testDeletePipeline() throws IOException {
             // end::delete-pipeline-request-timeout
 
             // tag::delete-pipeline-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::delete-pipeline-request-masterTimeout
 
             // tag::delete-pipeline-execute
@@ -314,7 +314,7 @@ public void testSimulatePipeline() throws IOException {
                 "}";
             SimulatePipelineRequest request = new SimulatePipelineRequest(
                 new BytesArray(source.getBytes(StandardCharsets.UTF_8)), // <1>
-                XContentType.JSON // <2>
+                MediaTypeRegistry.JSON // <2>
             );
             // end::simulate-pipeline-request
 
@@ -370,7 +370,7 @@ public void testSimulatePipelineAsync() throws Exception {
                 + "}";
             SimulatePipelineRequest request = new SimulatePipelineRequest(
                 new BytesArray(source.getBytes(StandardCharsets.UTF_8)),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             );
 
             // tag::simulate-pipeline-execute-listener
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/QueryDSLDocumentationTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/QueryDSLDocumentationTests.java
index 9f5c2e51a7960..4304ef04f6dc4 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/QueryDSLDocumentationTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/QueryDSLDocumentationTests.java
@@ -39,10 +39,10 @@
 import org.opensearch.common.geo.builders.MultiPointBuilder;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.index.query.GeoShapeQueryBuilder;
+import org.opensearch.index.query.RankFeatureQueryBuilders;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder.FilterFunctionBuilder;
 import org.opensearch.join.query.JoinQueryBuilders;
-import org.opensearch.index.query.RankFeatureQueryBuilders;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SearchDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SearchDocumentationIT.java
index d514f66ff36d9..bf0f70304168e 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SearchDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SearchDocumentationIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.bulk.BulkResponse;
@@ -65,13 +64,15 @@
 import org.opensearch.client.core.CountResponse;
 import org.opensearch.client.indices.CreateIndexRequest;
 import org.opensearch.client.indices.CreateIndexResponse;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
@@ -86,7 +87,6 @@
 import org.opensearch.index.rankeval.RatedDocument;
 import org.opensearch.index.rankeval.RatedRequest;
 import org.opensearch.index.rankeval.RatedSearchHit;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.ScriptType;
 import org.opensearch.script.mustache.MultiSearchTemplateRequest;
 import org.opensearch.script.mustache.MultiSearchTemplateResponse;
@@ -319,9 +319,9 @@ public void testSearchRequestAggregations() throws IOException {
         RestHighLevelClient client = highLevelClient();
         {
             BulkRequest request = new BulkRequest();
-            request.add(new IndexRequest("posts").id("1").source(XContentType.JSON, "company", "OpenSearch", "age", 20));
-            request.add(new IndexRequest("posts").id("2").source(XContentType.JSON, "company", "OpenSearch", "age", 30));
-            request.add(new IndexRequest("posts").id("3").source(XContentType.JSON, "company", "OpenSearch", "age", 40));
+            request.add(new IndexRequest("posts").id("1").source(MediaTypeRegistry.JSON, "company", "OpenSearch", "age", 20));
+            request.add(new IndexRequest("posts").id("2").source(MediaTypeRegistry.JSON, "company", "OpenSearch", "age", 30));
+            request.add(new IndexRequest("posts").id("3").source(MediaTypeRegistry.JSON, "company", "OpenSearch", "age", 40));
             request.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
             BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
             assertSame(RestStatus.OK, bulkResponse.status());
@@ -392,10 +392,10 @@ public void testSearchRequestSuggestions() throws IOException {
         RestHighLevelClient client = highLevelClient();
         {
             BulkRequest request = new BulkRequest();
-            request.add(new IndexRequest("posts").id("1").source(XContentType.JSON, "user", "foobar"));
-            request.add(new IndexRequest("posts").id("2").source(XContentType.JSON, "user", "quxx"));
-            request.add(new IndexRequest("posts").id("3").source(XContentType.JSON, "user", "quzz"));
-            request.add(new IndexRequest("posts").id("4").source(XContentType.JSON, "user", "corge"));
+            request.add(new IndexRequest("posts").id("1").source(MediaTypeRegistry.JSON, "user", "foobar"));
+            request.add(new IndexRequest("posts").id("2").source(MediaTypeRegistry.JSON, "user", "quxx"));
+            request.add(new IndexRequest("posts").id("3").source(MediaTypeRegistry.JSON, "user", "quzz"));
+            request.add(new IndexRequest("posts").id("4").source(MediaTypeRegistry.JSON, "user", "corge"));
             request.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
             BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
             assertSame(RestStatus.OK, bulkResponse.status());
@@ -438,7 +438,7 @@ public void testSearchRequestHighlighting() throws IOException {
             request.add(
                 new IndexRequest("posts").id("1")
                     .source(
-                        XContentType.JSON,
+                        MediaTypeRegistry.JSON,
                         "title",
                         "In which order are my OpenSearch queries executed?",
                         "user",
@@ -450,7 +450,7 @@ public void testSearchRequestHighlighting() throws IOException {
             request.add(
                 new IndexRequest("posts").id("2")
                     .source(
-                        XContentType.JSON,
+                        MediaTypeRegistry.JSON,
                         "title",
                         "Current status and upcoming changes in OpenSearch",
                         "user",
@@ -462,7 +462,7 @@ public void testSearchRequestHighlighting() throws IOException {
             request.add(
                 new IndexRequest("posts").id("3")
                     .source(
-                        XContentType.JSON,
+                        MediaTypeRegistry.JSON,
                         "title",
                         "The Future of Federated Search in OpenSearch",
                         "user",
@@ -525,7 +525,7 @@ public void testSearchRequestHighlighting() throws IOException {
     public void testSearchRequestProfiling() throws IOException {
         RestHighLevelClient client = highLevelClient();
         {
-            IndexRequest request = new IndexRequest("posts").id("1").source(XContentType.JSON, "tags", "opensearch", "comments", 123);
+            IndexRequest request = new IndexRequest("posts").id("1").source(MediaTypeRegistry.JSON, "tags", "opensearch", "comments", 123);
             request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL);
             IndexResponse indexResponse = client.index(request, RequestOptions.DEFAULT);
             assertSame(RestStatus.CREATED, indexResponse.status());
@@ -597,13 +597,15 @@ public void testScroll() throws Exception {
         {
             BulkRequest request = new BulkRequest();
             request.add(
-                new IndexRequest("posts").id("1").source(XContentType.JSON, "title", "In which order are my OpenSearch queries executed?")
+                new IndexRequest("posts").id("1")
+                    .source(MediaTypeRegistry.JSON, "title", "In which order are my OpenSearch queries executed?")
             );
             request.add(
-                new IndexRequest("posts").id("2").source(XContentType.JSON, "title", "Current status and upcoming changes in OpenSearch")
+                new IndexRequest("posts").id("2")
+                    .source(MediaTypeRegistry.JSON, "title", "Current status and upcoming changes in OpenSearch")
             );
             request.add(
-                new IndexRequest("posts").id("3").source(XContentType.JSON, "title", "The Future of Federated Search in OpenSearch")
+                new IndexRequest("posts").id("3").source(MediaTypeRegistry.JSON, "title", "The Future of Federated Search in OpenSearch")
             );
             request.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
             BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
@@ -1320,7 +1322,7 @@ private void indexSearchTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("posts").id("1")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "id",
                     1,
                     "title",
@@ -1334,7 +1336,7 @@ private void indexSearchTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("posts").id("2")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "id",
                     2,
                     "title",
@@ -1348,7 +1350,7 @@ private void indexSearchTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("posts").id("3")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "id",
                     3,
                     "title",
@@ -1360,8 +1362,8 @@ private void indexSearchTestData() throws IOException {
                 )
         );
 
-        bulkRequest.add(new IndexRequest("authors").id("1").source(XContentType.JSON, "id", 1, "user", "foobar"));
-        bulkRequest.add(new IndexRequest("contributors").id("1").source(XContentType.JSON, "id", 1, "user", "quuz"));
+        bulkRequest.add(new IndexRequest("authors").id("1").source(MediaTypeRegistry.JSON, "id", 1, "user", "foobar"));
+        bulkRequest.add(new IndexRequest("contributors").id("1").source(MediaTypeRegistry.JSON, "id", 1, "user", "quuz"));
 
         bulkRequest.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
         BulkResponse bulkResponse = highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT);
@@ -1472,7 +1474,7 @@ private static void indexCountTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("blog").id("1")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "title",
                     "Doubling Down on Open?",
                     "user",
@@ -1484,7 +1486,7 @@ private static void indexCountTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("blog").id("2")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "title",
                     "XYZ Joins Forces with OpenSearch",
                     "user",
@@ -1496,7 +1498,7 @@ private static void indexCountTestData() throws IOException {
         bulkRequest.add(
             new IndexRequest("blog").id("3")
                 .source(
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "title",
                     "On Net Neutrality",
                     "user",
@@ -1506,7 +1508,7 @@ private static void indexCountTestData() throws IOException {
                 )
         );
 
-        bulkRequest.add(new IndexRequest("author").id("1").source(XContentType.JSON, "user", "foobar"));
+        bulkRequest.add(new IndexRequest("author").id("1").source(MediaTypeRegistry.JSON, "user", "foobar"));
 
         bulkRequest.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
         BulkResponse bulkResponse = highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SnapshotClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SnapshotClientDocumentationIT.java
index 0ca3c0cd5a598..50bcf79642eac 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SnapshotClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/SnapshotClientDocumentationIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client.documentation;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryRequest;
 import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesRequest;
@@ -64,9 +63,10 @@
 import org.opensearch.common.Booleans;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.repositories.fs.FsRepository;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.snapshots.RestoreInfo;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
@@ -156,7 +156,7 @@ public void testSnapshotCreateRepository() throws IOException {
         {
             // tag::create-repository-settings-source
             request.settings("{\"location\": \".\", \"compress\": \"true\"}",
-                XContentType.JSON); // <1>
+                MediaTypeRegistry.JSON); // <1>
             // end::create-repository-settings-source
         }
 
@@ -168,8 +168,8 @@ public void testSnapshotCreateRepository() throws IOException {
         // end::create-repository-request-type
 
         // tag::create-repository-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::create-repository-request-masterTimeout
         // tag::create-repository-request-timeout
         request.timeout(TimeValue.timeValueMinutes(1)); // <1>
@@ -238,8 +238,8 @@ public void testSnapshotGetRepository() throws IOException {
         request.local(true); // <1>
         // end::get-repository-request-local
         // tag::get-repository-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::get-repository-request-masterTimeout
 
         // tag::get-repository-execute
@@ -298,8 +298,8 @@ public void testRestoreSnapshot() throws IOException {
         // we need to restore as a different index name
 
         // tag::restore-snapshot-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::restore-snapshot-request-masterTimeout
 
         // tag::restore-snapshot-request-waitForCompletion
@@ -395,8 +395,8 @@ public void testSnapshotDeleteRepository() throws IOException {
         // end::delete-repository-request
 
         // tag::delete-repository-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::delete-repository-request-masterTimeout
         // tag::delete-repository-request-timeout
         request.timeout(TimeValue.timeValueMinutes(1)); // <1>
@@ -454,8 +454,8 @@ public void testSnapshotVerifyRepository() throws IOException {
         // end::verify-repository-request
 
         // tag::verify-repository-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::verify-repository-request-masterTimeout
         // tag::verify-repository-request-timeout
         request.timeout(TimeValue.timeValueMinutes(1)); // <1>
@@ -544,8 +544,8 @@ public void testSnapshotCreate() throws IOException {
         // end::create-snapshot-request-includeGlobalState
 
         // tag::create-snapshot-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::create-snapshot-request-masterTimeout
         // tag::create-snapshot-request-waitForCompletion
         request.waitForCompletion(true); // <1>
@@ -622,8 +622,8 @@ public void testSnapshotGetSnapshots() throws IOException {
         // end::get-snapshots-request-snapshots
 
         // tag::get-snapshots-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::get-snapshots-request-masterTimeout
 
         // tag::get-snapshots-request-verbose
@@ -704,8 +704,8 @@ public void testSnapshotSnapshotsStatus() throws IOException {
         request.ignoreUnavailable(true); // <1>
         // end::snapshots-status-request-ignoreUnavailable
         // tag::snapshots-status-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::snapshots-status-request-masterTimeout
 
         // tag::snapshots-status-execute
@@ -769,8 +769,8 @@ public void testSnapshotDeleteSnapshot() throws IOException {
         // end::delete-snapshot-request
 
         // tag::delete-snapshot-request-masterTimeout
-        request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-        request.masterNodeTimeout("1m"); // <2>
+        request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+        request.clusterManagerNodeTimeout("1m"); // <2>
         // end::delete-snapshot-request-masterTimeout
 
         // tag::delete-snapshot-execute
@@ -818,7 +818,7 @@ public void onFailure(Exception e) {
     private void createTestRepositories() throws IOException {
         PutRepositoryRequest request = new PutRepositoryRequest(repositoryName);
         request.type(FsRepository.TYPE);
-        request.settings("{\"location\": \".\"}", XContentType.JSON);
+        request.settings("{\"location\": \".\"}", MediaTypeRegistry.JSON);
         assertTrue(highLevelClient().snapshot().createRepository(request, RequestOptions.DEFAULT).isAcknowledged());
     }
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/StoredScriptsDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/StoredScriptsDocumentationIT.java
index c9c36a6165c45..6916ae11556e2 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/StoredScriptsDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/StoredScriptsDocumentationIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.client.documentation;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.cluster.storedscripts.DeleteStoredScriptRequest;
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptRequest;
@@ -42,12 +41,13 @@
 import org.opensearch.client.OpenSearchRestHighLevelClientTestCase;
 import org.opensearch.client.RequestOptions;
 import org.opensearch.client.RestHighLevelClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.Script;
 import org.opensearch.script.StoredScriptSource;
 
@@ -88,7 +88,7 @@ public void testGetStoredScript() throws Exception {
         final StoredScriptSource scriptSource = new StoredScriptSource(
             "painless",
             "Math.log(_score * 2) + params.my_modifier",
-            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
         );
 
         putStoredScript("calculate-score", scriptSource);
@@ -99,8 +99,8 @@ public void testGetStoredScript() throws Exception {
             // end::get-stored-script-request
 
             // tag::get-stored-script-request-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueSeconds(50)); // <1>
-            request.masterNodeTimeout("50s"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueSeconds(50)); // <1>
+            request.clusterManagerNodeTimeout("50s"); // <2>
             // end::get-stored-script-request-masterTimeout
 
             // tag::get-stored-script-execute
@@ -152,7 +152,7 @@ public void testDeleteStoredScript() throws Exception {
         final StoredScriptSource scriptSource = new StoredScriptSource(
             "painless",
             "Math.log(_score * 2) + params.my_modifier",
-            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
         );
 
         putStoredScript("calculate-score", scriptSource);
@@ -162,8 +162,8 @@ public void testDeleteStoredScript() throws Exception {
         // end::delete-stored-script-request
 
         // tag::delete-stored-script-request-masterTimeout
-        deleteRequest.masterNodeTimeout(TimeValue.timeValueSeconds(50)); // <1>
-        deleteRequest.masterNodeTimeout("50s"); // <2>
+        deleteRequest.clusterManagerNodeTimeout(TimeValue.timeValueSeconds(50)); // <1>
+        deleteRequest.clusterManagerNodeTimeout("50s"); // <2>
         // end::delete-stored-script-request-masterTimeout
 
         // tag::delete-stored-script-request-timeout
@@ -221,7 +221,7 @@ public void testPutScript() throws Exception {
                     "\"source\": \"Math.log(_score * 2) + params.multiplier\"" +
                     "}\n" +
                     "}\n"
-            ), XContentType.JSON); // <2>
+            ), MediaTypeRegistry.JSON); // <2>
             // end::put-stored-script-request
 
             // tag::put-stored-script-context
@@ -234,8 +234,8 @@ public void testPutScript() throws Exception {
             // end::put-stored-script-timeout
 
             // tag::put-stored-script-masterTimeout
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
-            request.masterNodeTimeout("1m"); // <2>
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.clusterManagerNodeTimeout("1m"); // <2>
             // end::put-stored-script-masterTimeout
         }
 
@@ -255,7 +255,7 @@ public void testPutScript() throws Exception {
                 builder.endObject();
             }
             builder.endObject();
-            request.content(BytesReference.bytes(builder), XContentType.JSON); // <1>
+            request.content(BytesReference.bytes(builder), MediaTypeRegistry.JSON); // <1>
             // end::put-stored-script-content-painless
 
             // tag::put-stored-script-execute
@@ -310,7 +310,7 @@ public void onFailure(Exception e) {
                 builder.endObject();
             }
             builder.endObject();
-            request.content(BytesReference.bytes(builder), XContentType.JSON); // <1>
+            request.content(BytesReference.bytes(builder), MediaTypeRegistry.JSON); // <1>
             // end::put-stored-script-content-mustache
 
             client.putScript(request, RequestOptions.DEFAULT);
@@ -322,7 +322,13 @@ public void onFailure(Exception e) {
     }
 
     private void putStoredScript(String id, StoredScriptSource scriptSource) throws IOException {
-        PutStoredScriptRequest request = new PutStoredScriptRequest(id, "score", new BytesArray("{}"), XContentType.JSON, scriptSource);
+        PutStoredScriptRequest request = new PutStoredScriptRequest(
+            id,
+            "score",
+            new BytesArray("{}"),
+            MediaTypeRegistry.JSON,
+            scriptSource
+        );
         assertAcked(execute(request, highLevelClient()::putScript, highLevelClient()::putScriptAsync));
     }
 }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/TasksClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/TasksClientDocumentationIT.java
index 05479e2e3e81c..03e267aafd1b7 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/documentation/TasksClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/documentation/TasksClientDocumentationIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.client.documentation;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
@@ -45,7 +44,8 @@
 import org.opensearch.client.tasks.CancelTasksRequest;
 import org.opensearch.client.tasks.CancelTasksResponse;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeGlobalRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeGlobalRequestTests.java
index d90c7184e877d..13f37d9d2509a 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeGlobalRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeGlobalRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeIndexRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeIndexRequestTests.java
index 400bfcffb44e7..6d85f961cb79e 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeIndexRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeIndexRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeResponseTests.java
index 41b91fcaec340..dadd64f8329cc 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/AnalyzeResponseTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.RandomObjects;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexRequestTests.java
index c96e296891fb9..1b93c478fcb7d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexRequestTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.TimedRequest;
 import org.opensearch.client.ValidationException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Optional;
@@ -75,15 +75,15 @@ public void testWaitForActiveShards() {
     public void testTimeout() {
         final CloseIndexRequest request = new CloseIndexRequest("index");
         assertEquals(request.timeout(), TimedRequest.DEFAULT_ACK_TIMEOUT);
-        assertEquals(request.masterNodeTimeout(), TimedRequest.DEFAULT_MASTER_NODE_TIMEOUT);
+        assertEquals(request.clusterManagerNodeTimeout(), TimedRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT);
 
         final TimeValue timeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
         request.setTimeout(timeout);
 
-        final TimeValue masterTimeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
-        request.setMasterTimeout(masterTimeout);
+        final TimeValue clusterManagerTimeout = TimeValue.timeValueSeconds(randomIntBetween(0, 1000));
+        request.setClusterManagerTimeout(clusterManagerTimeout);
 
         assertEquals(request.timeout(), timeout);
-        assertEquals(request.masterNodeTimeout(), masterTimeout);
+        assertEquals(request.clusterManagerNodeTimeout(), clusterManagerTimeout);
     }
 }
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexResponseTests.java
index 3fa35f6fffd22..6aafee142bd22 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CloseIndexResponseTests.java
@@ -35,16 +35,15 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.transport.ActionNotFoundTransportException;
 
 import java.io.IOException;
@@ -194,7 +193,7 @@ public final void testBwcFromXContent() throws IOException {
 
             final XContentType xContentType = randomFrom(XContentType.values());
             final BytesReference bytes = toShuffledXContent(expected, xContentType, getParams(), randomBoolean());
-            final XContent xContent = XContentFactory.xContent(xContentType);
+            final XContent xContent = xContentType.xContent();
             final XContentParser parser = xContent.createParser(
                 NamedXContentRegistry.EMPTY,
                 LoggingDeprecationHandler.INSTANCE,
@@ -215,7 +214,7 @@ public final void testBwcFromXContent() throws IOException {
 
             final XContentType xContentType = randomFrom(XContentType.values());
             final BytesReference bytes = toShuffledXContent(expected, xContentType, getParams(), randomBoolean());
-            final XContent xContent = XContentFactory.xContent(xContentType);
+            final XContent xContent = xContentType.xContent();
             final XContentParser parser = xContent.createParser(
                 NamedXContentRegistry.EMPTY,
                 LoggingDeprecationHandler.INSTANCE,
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CreateIndexRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CreateIndexRequestTests.java
index 6d9695c376e23..0cfbd8c29fe43 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/CreateIndexRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/CreateIndexRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.action.admin.indices.alias.Alias;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
@@ -69,8 +69,8 @@ private void assertMappingsEqual(CreateIndexRequest expected, CreateIndexRequest
         } else {
             assertNotNull(actual.mappings());
             try (
-                XContentParser expectedJson = createParser(expected.mappingsXContentType().xContent(), expected.mappings());
-                XContentParser actualJson = createParser(actual.mappingsXContentType().xContent(), actual.mappings())
+                XContentParser expectedJson = createParser(expected.mappingsMediaType().xContent(), expected.mappings());
+                XContentParser actualJson = createParser(actual.mappingsMediaType().xContent(), actual.mappings())
             ) {
                 assertEquals(expectedJson.map(), actualJson.map());
             } catch (IOException e) {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/DataStreamsStatsResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/DataStreamsStatsResponseTests.java
index c53aaffcbcaba..9418a82fc6107 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/DataStreamsStatsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/DataStreamsStatsResponseTests.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.indices.datastream.DataStreamsStatsAction;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComponentTemplatesResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComponentTemplatesResponseTests.java
index 03ca152501c00..fd7d79fc4532d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComponentTemplatesResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComponentTemplatesResponseTests.java
@@ -37,7 +37,7 @@
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponseTests.java
index d2fd4ed16299e..f8013c6cc3d5d 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetComposableIndexTemplatesResponseTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetDataStreamResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetDataStreamResponseTests.java
index 27d0a423b1b35..3f0d56a3d9455 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetDataStreamResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetDataStreamResponseTests.java
@@ -38,9 +38,9 @@
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetFieldMappingsResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetFieldMappingsResponseTests.java
index b866242085115..115685a2c5afc 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetFieldMappingsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetFieldMappingsResponseTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.client.indices.GetFieldMappingsResponse.FieldMappingMetadata;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexResponseTests.java
index 37f4d95d5f4d0..a00f0487116dc 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexResponseTests.java
@@ -37,11 +37,10 @@
 import org.opensearch.client.GetAliasesResponseTests;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.index.mapper.MapperService;
 
@@ -62,11 +61,11 @@ public class GetIndexResponseTests extends AbstractResponseTestCase<
     @Override
     protected org.opensearch.action.admin.indices.get.GetIndexResponse createServerTestInstance(XContentType xContentType) {
         String[] indices = generateRandomStringArray(5, 5, false, false);
-        ImmutableOpenMap.Builder<String, MappingMetadata> mappings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> aliases = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, Settings> settings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, Settings> defaultSettings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, String> dataStreams = ImmutableOpenMap.builder();
+        final Map<String, MappingMetadata> mappings = new HashMap<>();
+        final Map<String, List<AliasMetadata>> aliases = new HashMap<>();
+        final Map<String, Settings> settings = new HashMap<>();
+        final Map<String, Settings> defaultSettings = new HashMap<>();
+        final Map<String, String> dataStreams = new HashMap<>();
         IndexScopedSettings indexScopedSettings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS;
         boolean includeDefaults = randomBoolean();
         for (String index : indices) {
@@ -94,11 +93,11 @@ protected org.opensearch.action.admin.indices.get.GetIndexResponse createServerT
         }
         return new org.opensearch.action.admin.indices.get.GetIndexResponse(
             indices,
-            mappings.build(),
-            aliases.build(),
-            settings.build(),
-            defaultSettings.build(),
-            dataStreams.build()
+            mappings,
+            aliases,
+            settings,
+            defaultSettings,
+            dataStreams
         );
     }
 
@@ -113,10 +112,10 @@ protected void assertInstances(
         GetIndexResponse clientInstance
     ) {
         assertArrayEquals(serverTestInstance.getIndices(), clientInstance.getIndices());
-        assertMapEquals(serverTestInstance.getMappings(), clientInstance.getMappings());
-        assertMapEquals(serverTestInstance.getSettings(), clientInstance.getSettings());
-        assertMapEquals(serverTestInstance.defaultSettings(), clientInstance.getDefaultSettings());
-        assertMapEquals(serverTestInstance.getAliases(), clientInstance.getAliases());
+        assertEquals(serverTestInstance.getMappings(), clientInstance.getMappings());
+        assertEquals(serverTestInstance.getSettings(), clientInstance.getSettings());
+        assertEquals(serverTestInstance.defaultSettings(), clientInstance.getDefaultSettings());
+        assertEquals(serverTestInstance.getAliases(), clientInstance.getAliases());
     }
 
     private static MappingMetadata createMappingsForIndex() {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexTemplatesResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexTemplatesResponseTests.java
index ead5fd4087c0b..507dc7802283f 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexTemplatesResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetIndexTemplatesResponseTests.java
@@ -34,18 +34,18 @@
 
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -137,10 +137,10 @@ public void testParsingFromOpenSearchResponse() throws IOException {
                     assertThat(result.mappings().sourceAsMap(), equalTo(expectedMapping.get("_doc")));
 
                     assertThat(result.aliases().size(), equalTo(esIMD.aliases().size()));
-                    List<AliasMetadata> expectedAliases = Arrays.stream(esIMD.aliases().values().toArray(AliasMetadata.class))
+                    List<AliasMetadata> expectedAliases = Arrays.stream(esIMD.aliases().values().toArray(new AliasMetadata[0]))
                         .sorted(Comparator.comparing(AliasMetadata::alias))
                         .collect(Collectors.toList());
-                    List<AliasMetadata> actualAliases = Arrays.stream(result.aliases().values().toArray(AliasMetadata.class))
+                    List<AliasMetadata> actualAliases = Arrays.stream(result.aliases().values().toArray(new AliasMetadata[0]))
                         .sorted(Comparator.comparing(AliasMetadata::alias))
                         .collect(Collectors.toList());
                     for (int j = 0; j < result.aliases().size(); j++) {
@@ -164,7 +164,7 @@ private Predicate<String> randomFieldsExcludeFilter() {
     private static void assertEqualInstances(GetIndexTemplatesResponse expectedInstance, GetIndexTemplatesResponse newInstance) {
         assertEquals(expectedInstance, newInstance);
         // Check there's no doc types at the root of the mapping
-        Map<String, Object> expectedMap = XContentHelper.convertToMap(new BytesArray(mappingString), true, XContentType.JSON).v2();
+        Map<String, Object> expectedMap = XContentHelper.convertToMap(new BytesArray(mappingString), true, MediaTypeRegistry.JSON).v2();
         for (IndexTemplateMetadata template : newInstance.getIndexTemplates()) {
             MappingMetadata mappingMD = template.mappings();
             if (mappingMD != null) {
@@ -194,7 +194,7 @@ static GetIndexTemplatesResponse createTestInstance() {
                 templateBuilder.version(between(0, 100));
             }
             if (randomBoolean()) {
-                Map<String, Object> map = XContentHelper.convertToMap(new BytesArray(mappingString), true, XContentType.JSON).v2();
+                Map<String, Object> map = XContentHelper.convertToMap(new BytesArray(mappingString), true, MediaTypeRegistry.JSON).v2();
                 MappingMetadata mapping = new MappingMetadata(MapperService.SINGLE_MAPPING_NAME, map);
                 templateBuilder.mapping(mapping);
             }
@@ -216,7 +216,7 @@ static void toXContent(GetIndexTemplatesResponse response, XContentBuilder build
 
             serverTemplateBuilder.patterns(clientITMD.patterns());
 
-            Iterator<AliasMetadata> aliases = clientITMD.aliases().valuesIt();
+            Iterator<AliasMetadata> aliases = clientITMD.aliases().values().iterator();
             aliases.forEachRemaining((a) -> serverTemplateBuilder.putAlias(a));
 
             serverTemplateBuilder.settings(clientITMD.settings());
@@ -262,7 +262,7 @@ private static AliasMetadata randomAliasMetadata(String name) {
     }
 
     static XContentBuilder randomMapping(String type, XContentType xContentType) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType);
         builder.startObject().startObject(type);
 
         randomMappingFields(builder, true);
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetMappingsResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetMappingsResponseTests.java
index cb62b116de020..6d80cdd3ad074 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetMappingsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/GetMappingsResponseTests.java
@@ -34,9 +34,8 @@
 
 import org.opensearch.client.AbstractResponseTestCase;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -50,12 +49,12 @@ public class GetMappingsResponseTests extends AbstractResponseTestCase<
 
     @Override
     protected org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse createServerTestInstance(XContentType xContentType) {
-        ImmutableOpenMap.Builder<String, MappingMetadata> mappings = ImmutableOpenMap.builder();
+        final Map<String, MappingMetadata> mappings = new HashMap<>();
         int numberOfIndexes = randomIntBetween(1, 5);
         for (int i = 0; i < numberOfIndexes; i++) {
             mappings.put("index-" + randomAlphaOfLength(5), randomMappingMetadata());
         }
-        return new org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse(mappings.build());
+        return new org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse(mappings);
     }
 
     @Override
@@ -68,7 +67,7 @@ protected void assertInstances(
         org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse serverTestInstance,
         GetMappingsResponse clientInstance
     ) {
-        assertMapEquals(serverTestInstance.getMappings(), clientInstance.mappings());
+        assertEquals(serverTestInstance.getMappings(), clientInstance.mappings());
     }
 
     public static MappingMetadata randomMappingMetadata() {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutIndexTemplateRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutIndexTemplateRequestTests.java
index f3800ac430ed1..e4c8e589b17ee 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutIndexTemplateRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutIndexTemplateRequestTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutMappingRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutMappingRequestTests.java
index 6065be82ddb22..fb00bad09f61a 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutMappingRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/PutMappingRequestTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
@@ -74,8 +74,8 @@ protected boolean supportsUnknownFields() {
     protected void assertEqualInstances(PutMappingRequest expected, PutMappingRequest actual) {
         if (actual.source() != null) {
             try (
-                XContentParser expectedJson = createParser(expected.xContentType().xContent(), expected.source());
-                XContentParser actualJson = createParser(actual.xContentType().xContent(), actual.source())
+                XContentParser expectedJson = createParser(expected.mediaType().xContent(), expected.source());
+                XContentParser actualJson = createParser(actual.mediaType().xContent(), actual.source())
             ) {
                 assertEquals(expectedJson.mapOrdered(), actualJson.mapOrdered());
             } catch (IOException e) {
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/RandomCreateIndexGenerator.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/RandomCreateIndexGenerator.java
index b50bb444cd00a..1f747dc139d15 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/RandomCreateIndexGenerator.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/RandomCreateIndexGenerator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.client.indices;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeRequestTests.java
index d5ff513676e48..1de3010a65247 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeRequestTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.client.AbstractRequestTestCase;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeResponseTests.java
index 954efed52d79a..919cc89a9ae44 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/ResizeResponseTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.client.indices;
 
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverRequestTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverRequestTests.java
index 9d51c09ba2e44..b4e0fc8f7f38c 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverRequestTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverRequestTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.action.admin.indices.rollover.MaxAgeCondition;
 import org.opensearch.action.admin.indices.rollover.MaxDocsCondition;
 import org.opensearch.action.admin.indices.rollover.MaxSizeCondition;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverResponseTests.java
index 0c924bc06046c..14477f07f8b42 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/indices/rollover/RolloverResponseTests.java
@@ -36,9 +36,9 @@
 import org.opensearch.action.admin.indices.rollover.MaxAgeCondition;
 import org.opensearch.action.admin.indices.rollover.MaxDocsCondition;
 import org.opensearch.action.admin.indices.rollover.MaxSizeCondition;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/CancelTasksResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/CancelTasksResponseTests.java
index 552a3712eea40..faf5024d0c173 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/CancelTasksResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/CancelTasksResponseTests.java
@@ -38,14 +38,14 @@
 import org.opensearch.client.AbstractResponseTestCase;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
@@ -84,6 +84,10 @@ protected CancelTasksResponseTests.ByNodeCancelTasksResponse createServerTestIns
         for (int i = 0; i < 4; i++) {
             boolean cancellable = randomBoolean();
             boolean cancelled = cancellable == true ? randomBoolean() : false;
+            Long cancellationStartTime = null;
+            if (cancelled) {
+                cancellationStartTime = randomNonNegativeLong();
+            }
             tasks.add(
                 new org.opensearch.tasks.TaskInfo(
                     new TaskId(NODE_ID, (long) i),
@@ -96,7 +100,9 @@ protected CancelTasksResponseTests.ByNodeCancelTasksResponse createServerTestIns
                     cancellable,
                     cancelled,
                     new TaskId("node1", randomLong()),
-                    Collections.singletonMap("x-header-of", "some-value")
+                    Collections.singletonMap("x-header-of", "some-value"),
+                    null,
+                    cancellationStartTime
                 )
             );
         }
@@ -134,6 +140,7 @@ protected void assertInstances(
             assertEquals(ti.isCancelled(), taskInfo.isCancelled());
             assertEquals(ti.getParentTaskId().getNodeId(), taskInfo.getParentTaskId().getNodeId());
             assertEquals(ti.getParentTaskId().getId(), taskInfo.getParentTaskId().getId());
+            assertEquals(ti.getCancellationStartTime(), taskInfo.getCancellationStartTime());
             FakeTaskStatus status = (FakeTaskStatus) ti.getStatus();
             assertEquals(status.code, taskInfo.getStatus().get("code"));
             assertEquals(status.status, taskInfo.getStatus().get("status"));
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/OpenSearchExceptionTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/OpenSearchExceptionTests.java
index 42d6a3f560660..fb8e4f731fb19 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/OpenSearchExceptionTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/OpenSearchExceptionTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.client.tasks;
 
 import org.opensearch.client.AbstractResponseTestCase;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/TaskSubmissionResponseTests.java b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/TaskSubmissionResponseTests.java
index b2f60ca53841f..ebef17ba2f161 100644
--- a/client/rest-high-level/src/test/java/org/opensearch/client/tasks/TaskSubmissionResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/opensearch/client/tasks/TaskSubmissionResponseTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.client.tasks;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/client/rest/build.gradle b/client/rest/build.gradle
index 5c1252061443a..894c15b1dbc49 100644
--- a/client/rest/build.gradle
+++ b/client/rest/build.gradle
@@ -33,11 +33,15 @@ import de.thetaphi.forbiddenapis.gradle.CheckForbiddenApis
 apply plugin: 'opensearch.build'
 apply plugin: 'opensearch.publish'
 
-targetCompatibility = JavaVersion.VERSION_11
-sourceCompatibility = JavaVersion.VERSION_11
+java {
+  targetCompatibility = JavaVersion.VERSION_11
+  sourceCompatibility = JavaVersion.VERSION_11
+}
 
-group = 'org.opensearch.client'
-archivesBaseName = 'opensearch-rest-client'
+base {
+  group = 'org.opensearch.client'
+  archivesBaseName = 'opensearch-rest-client'
+}
 
 dependencies {
   api "org.apache.httpcomponents:httpclient:${versions.httpclient}"
@@ -54,6 +58,10 @@ dependencies {
   testImplementation "org.mockito:mockito-core:${versions.mockito}"
   testImplementation "org.objenesis:objenesis:${versions.objenesis}"
   testImplementation "net.bytebuddy:byte-buddy:${versions.bytebuddy}"
+  testImplementation "net.bytebuddy:byte-buddy-agent:${versions.bytebuddy}"
+  testImplementation "org.apache.logging.log4j:log4j-api:${versions.log4j}"
+  testImplementation "org.apache.logging.log4j:log4j-core:${versions.log4j}"
+  testImplementation "org.apache.logging.log4j:log4j-jul:${versions.log4j}"
 }
 
 tasks.withType(CheckForbiddenApis).configureEach {
@@ -89,7 +97,6 @@ thirdPartyAudit.ignoreMissingClasses(
   'org.apache.avalon.framework.logger.Logger',
   'org.apache.log.Hierarchy',
   'org.apache.log.Logger',
-  'org.apache.log4j.Category',
   'org.apache.log4j.Level',
   'org.apache.log4j.Logger',
   'org.apache.log4j.Priority',
diff --git a/client/rest/licenses/commons-codec-1.13.jar.sha1 b/client/rest/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/client/rest/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/client/rest/licenses/commons-codec-1.15.jar.sha1 b/client/rest/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/client/rest/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/client/rest/licenses/commons-logging-1.1.3.jar.sha1 b/client/rest/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index 5b8f029e58293..0000000000000
--- a/client/rest/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
\ No newline at end of file
diff --git a/client/rest/licenses/commons-logging-1.2.jar.sha1 b/client/rest/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/client/rest/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/client/rest/licenses/httpasyncclient-4.1.4.jar.sha1 b/client/rest/licenses/httpasyncclient-4.1.4.jar.sha1
deleted file mode 100644
index 8360ab45c7ab3..0000000000000
--- a/client/rest/licenses/httpasyncclient-4.1.4.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f3a3240681faae3fa46b573a4c7e50cec9db0d86
\ No newline at end of file
diff --git a/client/rest/licenses/httpasyncclient-4.1.5.jar.sha1 b/client/rest/licenses/httpasyncclient-4.1.5.jar.sha1
new file mode 100644
index 0000000000000..366a9e31069a6
--- /dev/null
+++ b/client/rest/licenses/httpasyncclient-4.1.5.jar.sha1
@@ -0,0 +1 @@
+cd18227f1eb8e9a263286c1d7362ceb24f6f9b32
\ No newline at end of file
diff --git a/client/rest/licenses/httpclient-4.5.13.jar.sha1 b/client/rest/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/client/rest/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/client/rest/licenses/httpclient-4.5.14.jar.sha1 b/client/rest/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/client/rest/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/client/rest/licenses/httpcore-4.4.12.jar.sha1 b/client/rest/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/client/rest/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/client/rest/licenses/httpcore-4.4.16.jar.sha1 b/client/rest/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/client/rest/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/client/rest/licenses/httpcore-nio-4.4.12.jar.sha1 b/client/rest/licenses/httpcore-nio-4.4.12.jar.sha1
deleted file mode 100644
index 4de932dc5aca0..0000000000000
--- a/client/rest/licenses/httpcore-nio-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-84cd29eca842f31db02987cfedea245af020198b
\ No newline at end of file
diff --git a/client/rest/licenses/httpcore-nio-4.4.16.jar.sha1 b/client/rest/licenses/httpcore-nio-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..f4749c11e4b27
--- /dev/null
+++ b/client/rest/licenses/httpcore-nio-4.4.16.jar.sha1
@@ -0,0 +1 @@
+cd21c80a9956be48c4c1cfd2f594ba02857d0927
\ No newline at end of file
diff --git a/client/rest/src/main/java/org/opensearch/client/Node.java b/client/rest/src/main/java/org/opensearch/client/Node.java
index c982ae8eb931f..2fa6605d57ad2 100644
--- a/client/rest/src/main/java/org/opensearch/client/Node.java
+++ b/client/rest/src/main/java/org/opensearch/client/Node.java
@@ -210,12 +210,21 @@ public Roles(final Set<String> roles) {
         }
 
         /**
-         * Returns whether or not the node <strong>could</strong> be elected master.
+         * Returns whether or not the node <strong>could</strong> be elected cluster-manager.
          */
-        public boolean isMasterEligible() {
+        public boolean isClusterManagerEligible() {
             return roles.contains("master") || roles.contains("cluster_manager");
         }
 
+        /**
+         * Returns whether or not the node <strong>could</strong> be elected cluster-manager.
+         * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isClusterManagerEligible()}
+         */
+        @Deprecated
+        public boolean isMasterEligible() {
+            return isClusterManagerEligible();
+        }
+
         /**
          * Returns whether or not the node stores data.
          */
@@ -230,6 +239,13 @@ public boolean isIngest() {
             return roles.contains("ingest");
         }
 
+        /**
+         * Returns whether the node is dedicated to provide search capability.
+         */
+        public boolean isSearch() {
+            return roles.contains("search");
+        }
+
         @Override
         public String toString() {
             return String.join(",", roles);
diff --git a/client/rest/src/main/java/org/opensearch/client/NodeSelector.java b/client/rest/src/main/java/org/opensearch/client/NodeSelector.java
index 09d5a2c1fe576..a54c6b1514717 100644
--- a/client/rest/src/main/java/org/opensearch/client/NodeSelector.java
+++ b/client/rest/src/main/java/org/opensearch/client/NodeSelector.java
@@ -36,7 +36,7 @@
 
 /**
  * Selects nodes that can receive requests. Used to keep requests away
- * from master nodes or to send them to nodes with a particular attribute.
+ * from cluster-manager nodes or to send them to nodes with a particular attribute.
  * Use with {@link RestClientBuilder#setNodeSelector(NodeSelector)}.
  */
 public interface NodeSelector {
@@ -80,16 +80,18 @@ public String toString() {
 
     /**
      * Selector that matches any node that has metadata and doesn't
-     * have the {@code master} role OR it has the data {@code data}
+     * have the {@code cluster_manager} role OR it has the data {@code data}
      * role.
      */
-    NodeSelector SKIP_DEDICATED_MASTERS = new NodeSelector() {
+    NodeSelector SKIP_DEDICATED_CLUSTER_MANAGERS = new NodeSelector() {
         @Override
         public void select(Iterable<Node> nodes) {
             for (Iterator<Node> itr = nodes.iterator(); itr.hasNext();) {
                 Node node = itr.next();
                 if (node.getRoles() == null) continue;
-                if (node.getRoles().isMasterEligible() && false == node.getRoles().isData() && false == node.getRoles().isIngest()) {
+                if (node.getRoles().isClusterManagerEligible()
+                    && false == node.getRoles().isData()
+                    && false == node.getRoles().isIngest()) {
                     itr.remove();
                 }
             }
@@ -97,7 +99,7 @@ public void select(Iterable<Node> nodes) {
 
         @Override
         public String toString() {
-            return "SKIP_DEDICATED_MASTERS";
+            return "SKIP_DEDICATED_CLUSTER_MANAGERS";
         }
     };
 }
diff --git a/client/rest/src/main/java/org/opensearch/client/RestClient.java b/client/rest/src/main/java/org/opensearch/client/RestClient.java
index 4f899fd709112..946b06e46d6fc 100644
--- a/client/rest/src/main/java/org/opensearch/client/RestClient.java
+++ b/client/rest/src/main/java/org/opensearch/client/RestClient.java
@@ -41,9 +41,9 @@
 import org.apache.http.HttpResponse;
 import org.apache.http.client.AuthCache;
 import org.apache.http.client.ClientProtocolException;
+import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.entity.GzipCompressingEntity;
 import org.apache.http.client.entity.GzipDecompressingEntity;
-import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
 import org.apache.http.client.methods.HttpHead;
 import org.apache.http.client.methods.HttpOptions;
@@ -56,6 +56,7 @@
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.concurrent.FutureCallback;
 import org.apache.http.conn.ConnectTimeoutException;
+import org.apache.http.entity.HttpEntityWrapper;
 import org.apache.http.impl.auth.BasicScheme;
 import org.apache.http.impl.client.BasicAuthCache;
 import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
@@ -64,6 +65,7 @@
 import org.apache.http.nio.protocol.HttpAsyncResponseConsumer;
 
 import javax.net.ssl.SSLHandshakeException;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
@@ -131,6 +133,29 @@ public class RestClient implements Closeable {
     private volatile NodeTuple<List<Node>> nodeTuple;
     private final WarningsHandler warningsHandler;
     private final boolean compressionEnabled;
+    private final Optional<Boolean> chunkedEnabled;
+
+    RestClient(
+        CloseableHttpAsyncClient client,
+        Header[] defaultHeaders,
+        List<Node> nodes,
+        String pathPrefix,
+        FailureListener failureListener,
+        NodeSelector nodeSelector,
+        boolean strictDeprecationMode,
+        boolean compressionEnabled,
+        boolean chunkedEnabled
+    ) {
+        this.client = client;
+        this.defaultHeaders = Collections.unmodifiableList(Arrays.asList(defaultHeaders));
+        this.failureListener = failureListener;
+        this.pathPrefix = pathPrefix;
+        this.nodeSelector = nodeSelector;
+        this.warningsHandler = strictDeprecationMode ? WarningsHandler.STRICT : WarningsHandler.PERMISSIVE;
+        this.compressionEnabled = compressionEnabled;
+        this.chunkedEnabled = Optional.of(chunkedEnabled);
+        setNodes(nodes);
+    }
 
     RestClient(
         CloseableHttpAsyncClient client,
@@ -149,6 +174,7 @@ public class RestClient implements Closeable {
         this.nodeSelector = nodeSelector;
         this.warningsHandler = strictDeprecationMode ? WarningsHandler.STRICT : WarningsHandler.PERMISSIVE;
         this.compressionEnabled = compressionEnabled;
+        this.chunkedEnabled = Optional.empty();
         setNodes(nodes);
     }
 
@@ -583,36 +609,42 @@ private static void addSuppressedException(Exception suppressedException, Except
         }
     }
 
-    private static HttpRequestBase createHttpRequest(String method, URI uri, HttpEntity entity, boolean compressionEnabled) {
+    private HttpRequestBase createHttpRequest(String method, URI uri, HttpEntity entity) {
         switch (method.toUpperCase(Locale.ROOT)) {
             case HttpDeleteWithEntity.METHOD_NAME:
-                return addRequestBody(new HttpDeleteWithEntity(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpDeleteWithEntity(uri), entity);
             case HttpGetWithEntity.METHOD_NAME:
-                return addRequestBody(new HttpGetWithEntity(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpGetWithEntity(uri), entity);
             case HttpHead.METHOD_NAME:
-                return addRequestBody(new HttpHead(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpHead(uri), entity);
             case HttpOptions.METHOD_NAME:
-                return addRequestBody(new HttpOptions(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpOptions(uri), entity);
             case HttpPatch.METHOD_NAME:
-                return addRequestBody(new HttpPatch(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpPatch(uri), entity);
             case HttpPost.METHOD_NAME:
                 HttpPost httpPost = new HttpPost(uri);
-                addRequestBody(httpPost, entity, compressionEnabled);
+                addRequestBody(httpPost, entity);
                 return httpPost;
             case HttpPut.METHOD_NAME:
-                return addRequestBody(new HttpPut(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpPut(uri), entity);
             case HttpTrace.METHOD_NAME:
-                return addRequestBody(new HttpTrace(uri), entity, compressionEnabled);
+                return addRequestBody(new HttpTrace(uri), entity);
             default:
                 throw new UnsupportedOperationException("http method not supported: " + method);
         }
     }
 
-    private static HttpRequestBase addRequestBody(HttpRequestBase httpRequest, HttpEntity entity, boolean compressionEnabled) {
+    private HttpRequestBase addRequestBody(HttpRequestBase httpRequest, HttpEntity entity) {
         if (entity != null) {
             if (httpRequest instanceof HttpEntityEnclosingRequestBase) {
                 if (compressionEnabled) {
-                    entity = new ContentCompressingEntity(entity);
+                    if (chunkedEnabled.isPresent()) {
+                        entity = new ContentCompressingEntity(entity, chunkedEnabled.get());
+                    } else {
+                        entity = new ContentCompressingEntity(entity);
+                    }
+                } else if (chunkedEnabled.isPresent()) {
+                    entity = new ContentHttpEntity(entity, chunkedEnabled.get());
                 }
                 ((HttpEntityEnclosingRequestBase) httpRequest).setEntity(entity);
             } else {
@@ -782,7 +814,7 @@ private class InternalRequest {
             String ignoreString = params.remove("ignore");
             this.ignoreErrorCodes = getIgnoreErrorCodes(ignoreString, request.getMethod());
             URI uri = buildUri(pathPrefix, request.getEndpoint(), params);
-            this.httpRequest = createHttpRequest(request.getMethod(), uri, request.getEntity(), compressionEnabled);
+            this.httpRequest = createHttpRequest(request.getMethod(), uri, request.getEntity());
             this.cancellable = Cancellable.fromRequest(httpRequest);
             setHeaders(httpRequest, request.getOptions().getHeaders());
             setRequestConfig(httpRequest, request.getOptions().getRequestConfig());
@@ -936,6 +968,7 @@ private static Exception extractAndWrapCause(Exception exception) {
      * A gzip compressing entity that also implements {@code getContent()}.
      */
     public static class ContentCompressingEntity extends GzipCompressingEntity {
+        private Optional<Boolean> chunkedEnabled;
 
         /**
          * Creates a {@link ContentCompressingEntity} instance with the provided HTTP entity.
@@ -944,6 +977,18 @@ public static class ContentCompressingEntity extends GzipCompressingEntity {
          */
         public ContentCompressingEntity(HttpEntity entity) {
             super(entity);
+            this.chunkedEnabled = Optional.empty();
+        }
+
+        /**
+         * Creates a {@link ContentCompressingEntity} instance with the provided HTTP entity.
+         *
+         * @param entity the HTTP entity.
+         * @param chunkedEnabled force enable/disable chunked transfer-encoding.
+         */
+        public ContentCompressingEntity(HttpEntity entity, boolean chunkedEnabled) {
+            super(entity);
+            this.chunkedEnabled = Optional.of(chunkedEnabled);
         }
 
         @Override
@@ -954,6 +999,80 @@ public InputStream getContent() throws IOException {
             }
             return out.asInput();
         }
+
+        /**
+         * A gzip compressing entity doesn't work with chunked encoding with sigv4
+         *
+         * @return false
+         */
+        @Override
+        public boolean isChunked() {
+            return chunkedEnabled.orElseGet(super::isChunked);
+        }
+
+        /**
+         * A gzip entity requires content length in http headers.
+         *
+         * @return content length of gzip entity
+         */
+        @Override
+        public long getContentLength() {
+            if (chunkedEnabled.isPresent()) {
+                if (chunkedEnabled.get()) {
+                    return -1L;
+                } else {
+                    long size;
+                    try (InputStream is = getContent()) {
+                        size = is.readAllBytes().length;
+                    } catch (IOException ex) {
+                        size = -1L;
+                    }
+
+                    return size;
+                }
+            } else {
+                return super.getContentLength();
+            }
+        }
+    }
+
+    /**
+     * An entity that lets the caller specify the return value of {@code isChunked()}.
+     */
+    public static class ContentHttpEntity extends HttpEntityWrapper {
+        private Optional<Boolean> chunkedEnabled;
+
+        /**
+         * Creates a {@link ContentHttpEntity} instance with the provided HTTP entity.
+         *
+         * @param entity the HTTP entity.
+         */
+        public ContentHttpEntity(HttpEntity entity) {
+            super(entity);
+            this.chunkedEnabled = Optional.empty();
+        }
+
+        /**
+         * Creates a {@link ContentHttpEntity} instance with the provided HTTP entity.
+         *
+         * @param entity the HTTP entity.
+         * @param chunkedEnabled force enable/disable chunked transfer-encoding.
+         */
+        public ContentHttpEntity(HttpEntity entity, boolean chunkedEnabled) {
+            super(entity);
+            this.chunkedEnabled = Optional.of(chunkedEnabled);
+        }
+
+        /**
+         * A chunked entity requires transfer-encoding:chunked in http headers
+         * which requires isChunked to be true
+         *
+         * @return true
+         */
+        @Override
+        public boolean isChunked() {
+            return chunkedEnabled.orElseGet(super::isChunked);
+        }
     }
 
     /**
diff --git a/client/rest/src/main/java/org/opensearch/client/RestClientBuilder.java b/client/rest/src/main/java/org/opensearch/client/RestClientBuilder.java
index 0b259c7983ca5..4682c734a2172 100644
--- a/client/rest/src/main/java/org/opensearch/client/RestClientBuilder.java
+++ b/client/rest/src/main/java/org/opensearch/client/RestClientBuilder.java
@@ -41,11 +41,13 @@
 import org.apache.http.nio.conn.SchemeIOSessionStrategy;
 
 import javax.net.ssl.SSLContext;
+
 import java.security.AccessController;
 import java.security.NoSuchAlgorithmException;
 import java.security.PrivilegedAction;
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 
 /**
  * Helps creating a new {@link RestClient}. Allows to set the most common http client configuration options when internally
@@ -84,6 +86,7 @@ public final class RestClientBuilder {
     private NodeSelector nodeSelector = NodeSelector.ANY;
     private boolean strictDeprecationMode = false;
     private boolean compressionEnabled = false;
+    private Optional<Boolean> chunkedEnabled;
 
     /**
      * Creates a new builder instance and sets the hosts that the client will send requests to.
@@ -100,6 +103,7 @@ public final class RestClientBuilder {
             }
         }
         this.nodes = nodes;
+        this.chunkedEnabled = Optional.empty();
     }
 
     /**
@@ -238,6 +242,16 @@ public RestClientBuilder setCompressionEnabled(boolean compressionEnabled) {
         return this;
     }
 
+    /**
+     * Whether the REST client should use Transfer-Encoding: chunked for requests or not"
+     *
+     * @param chunkedEnabled force enable/disable chunked transfer-encoding.
+     */
+    public RestClientBuilder setChunkedEnabled(boolean chunkedEnabled) {
+        this.chunkedEnabled = Optional.of(chunkedEnabled);
+        return this;
+    }
+
     /**
      * Creates a new {@link RestClient} based on the provided configuration.
      */
@@ -248,16 +262,34 @@ public RestClient build() {
         CloseableHttpAsyncClient httpClient = AccessController.doPrivileged(
             (PrivilegedAction<CloseableHttpAsyncClient>) this::createHttpClient
         );
-        RestClient restClient = new RestClient(
-            httpClient,
-            defaultHeaders,
-            nodes,
-            pathPrefix,
-            failureListener,
-            nodeSelector,
-            strictDeprecationMode,
-            compressionEnabled
-        );
+
+        RestClient restClient = null;
+
+        if (chunkedEnabled.isPresent()) {
+            restClient = new RestClient(
+                httpClient,
+                defaultHeaders,
+                nodes,
+                pathPrefix,
+                failureListener,
+                nodeSelector,
+                strictDeprecationMode,
+                compressionEnabled,
+                chunkedEnabled.get()
+            );
+        } else {
+            restClient = new RestClient(
+                httpClient,
+                defaultHeaders,
+                nodes,
+                pathPrefix,
+                failureListener,
+                nodeSelector,
+                strictDeprecationMode,
+                compressionEnabled
+            );
+        }
+
         httpClient.start();
         return restClient;
     }
diff --git a/client/rest/src/test/java/org/opensearch/client/NodeSelectorTests.java b/client/rest/src/test/java/org/opensearch/client/NodeSelectorTests.java
index f7cb0733bb8c5..65a831e59bfb0 100644
--- a/client/rest/src/test/java/org/opensearch/client/NodeSelectorTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/NodeSelectorTests.java
@@ -55,33 +55,33 @@ public void testAny() {
         assertEquals(expected, nodes);
     }
 
-    public void testNotMasterOnly() {
-        Node masterOnly = dummyNode(true, false, false);
+    public void testNotClusterManagerOnly() {
+        Node clusterManagerOnly = dummyNode(true, false, false);
         Node all = dummyNode(true, true, true);
-        Node masterAndData = dummyNode(true, true, false);
-        Node masterAndIngest = dummyNode(true, false, true);
+        Node clusterManagerAndData = dummyNode(true, true, false);
+        Node clusterManagerAndIngest = dummyNode(true, false, true);
         Node coordinatingOnly = dummyNode(false, false, false);
         Node ingestOnly = dummyNode(false, false, true);
         Node data = dummyNode(false, true, randomBoolean());
         List<Node> nodes = new ArrayList<>();
-        nodes.add(masterOnly);
+        nodes.add(clusterManagerOnly);
         nodes.add(all);
-        nodes.add(masterAndData);
-        nodes.add(masterAndIngest);
+        nodes.add(clusterManagerAndData);
+        nodes.add(clusterManagerAndIngest);
         nodes.add(coordinatingOnly);
         nodes.add(ingestOnly);
         nodes.add(data);
         Collections.shuffle(nodes, getRandom());
         List<Node> expected = new ArrayList<>(nodes);
-        expected.remove(masterOnly);
-        NodeSelector.SKIP_DEDICATED_MASTERS.select(nodes);
+        expected.remove(clusterManagerOnly);
+        NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS.select(nodes);
         assertEquals(expected, nodes);
     }
 
-    private static Node dummyNode(boolean master, boolean data, boolean ingest) {
+    private static Node dummyNode(boolean clusterManager, boolean data, boolean ingest) {
         final Set<String> roles = new TreeSet<>();
-        if (master) {
-            roles.add("master");
+        if (clusterManager) {
+            roles.add("cluster_manager");
         }
         if (data) {
             roles.add("data");
@@ -98,4 +98,33 @@ private static Node dummyNode(boolean master, boolean data, boolean ingest) {
             Collections.<String, List<String>>emptyMap()
         );
     }
+
+    /*
+     * Validate SKIP_DEDICATED_CLUSTER_MANAGERS can filter both the deprecated "master" role and the new "cluster_manager" role.
+     * The test is a modified copy of the above testNotClusterManagerOnly().
+     */
+    public void testDeprecatedNotMasterOnly() {
+        Node clusterManagerOnly = dummyNode(true, false, false);
+        Node all = dummyNode(true, true, true);
+        Node data = dummyNode(false, true, randomBoolean());
+        Node deprecatedMasterOnly = new Node(
+            new HttpHost("dummy"),
+            Collections.emptySet(),
+            randomAsciiAlphanumOfLength(5),
+            randomAsciiAlphanumOfLength(5),
+            new Roles(Collections.singleton("master")),
+            Collections.emptyMap()
+        );
+        List<Node> nodes = new ArrayList<>();
+        nodes.add(clusterManagerOnly);
+        nodes.add(all);
+        nodes.add(data);
+        nodes.add(deprecatedMasterOnly);
+        Collections.shuffle(nodes, getRandom());
+        List<Node> expected = new ArrayList<>(nodes);
+        expected.remove(clusterManagerOnly);
+        expected.remove(deprecatedMasterOnly);
+        NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS.select(nodes);
+        assertEquals(expected, nodes);
+    }
 }
diff --git a/client/rest/src/test/java/org/opensearch/client/NodeTests.java b/client/rest/src/test/java/org/opensearch/client/NodeTests.java
index 352296fa3024a..8a5c881d3b1a0 100644
--- a/client/rest/src/test/java/org/opensearch/client/NodeTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/NodeTests.java
@@ -46,8 +46,10 @@
 import static java.util.Collections.singleton;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
 public class NodeTests extends RestClientTestCase {
@@ -161,4 +163,9 @@ public void testEqualsAndHashCode() {
             )
         );
     }
+
+    public void testIsSearchNode() {
+        Roles searchRole = new Roles(Collections.singleton("search"));
+        assertThat(searchRole.isSearch(), equalTo(true));
+    }
 }
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientBuilderIntegTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientBuilderIntegTests.java
index 10bf9568c8798..089138e4c65b9 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientBuilderIntegTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientBuilderIntegTests.java
@@ -36,6 +36,7 @@
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpsConfigurator;
 import com.sun.net.httpserver.HttpsServer;
+
 import org.apache.http.HttpHost;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -44,6 +45,7 @@
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLHandshakeException;
 import javax.net.ssl.TrustManagerFactory;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.InetAddress;
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientCompressionTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientCompressionTests.java
new file mode 100644
index 0000000000000..0cf00fb4ed5fd
--- /dev/null
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientCompressionTests.java
@@ -0,0 +1,166 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpHost;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.StringEntity;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.CompletableFuture;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
+
+public class RestClientCompressionTests extends RestClientTestCase {
+
+    private static HttpServer httpServer;
+
+    @BeforeClass
+    public static void startHttpServer() throws Exception {
+        httpServer = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        httpServer.createContext("/", new GzipResponseHandler());
+        httpServer.start();
+    }
+
+    @AfterClass
+    public static void stopHttpServers() throws IOException {
+        httpServer.stop(0);
+        httpServer = null;
+    }
+
+    /**
+     * A response handler that accepts gzip-encoded data and replies request and response encoding values
+     * followed by the request body. The response is compressed if "Accept-Encoding" is "gzip".
+     */
+    private static class GzipResponseHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange exchange) throws IOException {
+
+            // Decode body (if any)
+            String contentEncoding = exchange.getRequestHeaders().getFirst("Content-Encoding");
+            String contentLength = exchange.getRequestHeaders().getFirst("Content-Length");
+            InputStream body = exchange.getRequestBody();
+            boolean compressedRequest = false;
+            if ("gzip".equals(contentEncoding)) {
+                body = new GZIPInputStream(body);
+                compressedRequest = true;
+            }
+            byte[] bytes = readAll(body);
+            boolean compress = "gzip".equals(exchange.getRequestHeaders().getFirst("Accept-Encoding"));
+            if (compress) {
+                exchange.getResponseHeaders().add("Content-Encoding", "gzip");
+            }
+
+            exchange.sendResponseHeaders(200, 0);
+
+            // Encode response if needed
+            OutputStream out = exchange.getResponseBody();
+            if (compress) {
+                out = new GZIPOutputStream(out);
+            }
+
+            // Outputs <request-encoding|null>#<response-encoding|null>#<request-body>
+            out.write(String.valueOf(contentEncoding).getBytes(StandardCharsets.UTF_8));
+            out.write('#');
+            out.write((compress ? "gzip" : "null").getBytes(StandardCharsets.UTF_8));
+            out.write('#');
+            out.write((compressedRequest ? contentLength : "null").getBytes(StandardCharsets.UTF_8));
+            out.write('#');
+            out.write(bytes);
+            out.close();
+
+            exchange.close();
+        }
+    }
+
+    /**
+     * Read all bytes of an input stream and close it.
+     */
+    private static byte[] readAll(InputStream in) throws IOException {
+        byte[] buffer = new byte[1024];
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        int len = 0;
+        while ((len = in.read(buffer)) > 0) {
+            bos.write(buffer, 0, len);
+        }
+        in.close();
+        return bos.toByteArray();
+    }
+
+    private RestClient createClient(boolean enableCompression, boolean chunkedEnabled) {
+        InetSocketAddress address = httpServer.getAddress();
+        return RestClient.builder(new HttpHost(address.getHostString(), address.getPort(), "http"))
+            .setCompressionEnabled(enableCompression)
+            .setChunkedEnabled(chunkedEnabled)
+            .build();
+    }
+
+    public void testCompressingClientWithContentLengthSync() throws Exception {
+        RestClient restClient = createClient(true, false);
+
+        Request request = new Request("POST", "/");
+        request.setEntity(new StringEntity("compressing client", ContentType.TEXT_PLAIN));
+
+        Response response = restClient.performRequest(request);
+
+        HttpEntity entity = response.getEntity();
+        String content = new String(readAll(entity.getContent()), StandardCharsets.UTF_8);
+        // Content-Encoding#Accept-Encoding#Content-Length#Content
+        Assert.assertEquals("gzip#gzip#38#compressing client", content);
+
+        restClient.close();
+    }
+
+    public void testCompressingClientContentLengthAsync() throws Exception {
+        InetSocketAddress address = httpServer.getAddress();
+        RestClient restClient = createClient(true, false);
+
+        Request request = new Request("POST", "/");
+        request.setEntity(new StringEntity("compressing client", ContentType.TEXT_PLAIN));
+
+        FutureResponse futureResponse = new FutureResponse();
+        restClient.performRequestAsync(request, futureResponse);
+        Response response = futureResponse.get();
+
+        // Server should report it had a compressed request and sent back a compressed response
+        HttpEntity entity = response.getEntity();
+        String content = new String(readAll(entity.getContent()), StandardCharsets.UTF_8);
+
+        // Content-Encoding#Accept-Encoding#Content-Length#Content
+        Assert.assertEquals("gzip#gzip#38#compressing client", content);
+
+        restClient.close();
+    }
+
+    public static class FutureResponse extends CompletableFuture<Response> implements ResponseListener {
+        @Override
+        public void onSuccess(Response response) {
+            this.complete(response);
+        }
+
+        @Override
+        public void onFailure(Exception exception) {
+            this.completeExceptionally(exception);
+        }
+    }
+}
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientGzipCompressionTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientGzipCompressionTests.java
index 8c4d993517fee..570cd851e5842 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientGzipCompressionTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientGzipCompressionTests.java
@@ -35,6 +35,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
 import org.apache.http.entity.ContentType;
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsIntegTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsIntegTests.java
index 277446191a36e..ea39490979a76 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsIntegTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsIntegTests.java
@@ -35,6 +35,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.HttpHost;
 import org.junit.AfterClass;
 import org.junit.Before;
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsTests.java
index 0b7d2881ccb54..a373e11a8e759 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientMultipleHostsTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.client;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.http.Header;
 import org.apache.http.HttpHost;
 import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
@@ -297,7 +298,7 @@ public void testNodeSelector() throws Exception {
     }
 
     public void testSetNodes() throws Exception {
-        RestClient restClient = createRestClient(NodeSelector.SKIP_DEDICATED_MASTERS);
+        RestClient restClient = createRestClient(NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS);
         List<Node> newNodes = new ArrayList<>(nodes.size());
         for (int i = 0; i < nodes.size(); i++) {
             Node.Roles roles = i == 0
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostIntegTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostIntegTests.java
index 0500d282a506d..ad82cb7aab85c 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostIntegTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostIntegTests.java
@@ -36,6 +36,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.Consts;
 import org.apache.http.Header;
 import org.apache.http.HttpHost;
diff --git a/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostTests.java b/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostTests.java
index a2aef065c9ae8..c1df0a1c881a5 100644
--- a/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostTests.java
+++ b/client/rest/src/test/java/org/opensearch/client/RestClientSingleHostTests.java
@@ -64,10 +64,9 @@
 import org.apache.http.util.EntityUtils;
 import org.junit.After;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
-import org.mockito.stubbing.Answer;
 
 import javax.net.ssl.SSLHandshakeException;
+
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
@@ -86,6 +85,9 @@
 import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicReference;
 
+import org.mockito.ArgumentCaptor;
+import org.mockito.stubbing.Answer;
+
 import static java.util.Collections.singletonList;
 import static org.opensearch.client.RestClientTestUtil.getAllErrorStatusCodes;
 import static org.opensearch.client.RestClientTestUtil.getHttpMethods;
@@ -101,8 +103,8 @@
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -138,6 +140,7 @@ public void createRestClient() {
             failureListener,
             NodeSelector.ANY,
             strictDeprecationMode,
+            false,
             false
         );
     }
diff --git a/client/rest/src/test/java/org/opensearch/client/documentation/RestClientDocumentation.java b/client/rest/src/test/java/org/opensearch/client/documentation/RestClientDocumentation.java
index 82c4fc2896213..ae4b8f4f20a4d 100644
--- a/client/rest/src/test/java/org/opensearch/client/documentation/RestClientDocumentation.java
+++ b/client/rest/src/test/java/org/opensearch/client/documentation/RestClientDocumentation.java
@@ -62,6 +62,7 @@
 import org.opensearch.client.RestClientBuilder.HttpClientConfigCallback;
 
 import javax.net.ssl.SSLContext;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
@@ -133,7 +134,7 @@ public void usage() throws IOException, InterruptedException {
             //tag::rest-client-init-node-selector
             RestClientBuilder builder = RestClient.builder(
                 new HttpHost("localhost", 9200, "http"));
-            builder.setNodeSelector(NodeSelector.SKIP_DEDICATED_MASTERS); // <1>
+            builder.setNodeSelector(NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS); // <1>
             //end::rest-client-init-node-selector
         }
         {
diff --git a/client/sniffer/build.gradle b/client/sniffer/build.gradle
index bc4be1dd153e8..ab095ffdcefa8 100644
--- a/client/sniffer/build.gradle
+++ b/client/sniffer/build.gradle
@@ -30,11 +30,15 @@
 apply plugin: 'opensearch.build'
 apply plugin: 'opensearch.publish'
 
-targetCompatibility = JavaVersion.VERSION_11
-sourceCompatibility = JavaVersion.VERSION_11
+java {
+  targetCompatibility = JavaVersion.VERSION_11
+  sourceCompatibility = JavaVersion.VERSION_11
+}
 
-group = 'org.opensearch.client'
-archivesBaseName = 'opensearch-rest-client-sniffer'
+base {
+  group = 'org.opensearch.client'
+  archivesBaseName = 'opensearch-rest-client-sniffer'
+}
 
 dependencies {
   api project(":client:rest")
@@ -50,6 +54,7 @@ dependencies {
   testImplementation "org.mockito:mockito-core:${versions.mockito}"
   testImplementation "org.objenesis:objenesis:${versions.objenesis}"
   testImplementation "net.bytebuddy:byte-buddy:${versions.bytebuddy}"
+  testImplementation "net.bytebuddy:byte-buddy-agent:${versions.bytebuddy}"
 }
 
 tasks.named('forbiddenApisMain').configure {
@@ -88,7 +93,6 @@ thirdPartyAudit.ignoreMissingClasses(
   'org.apache.avalon.framework.logger.Logger',
   'org.apache.log.Hierarchy',
   'org.apache.log.Logger',
-  'org.apache.log4j.Category',
   'org.apache.log4j.Level',
   'org.apache.log4j.Logger',
   'org.apache.log4j.Priority',
diff --git a/client/sniffer/licenses/commons-codec-1.13.jar.sha1 b/client/sniffer/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/client/sniffer/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/client/sniffer/licenses/commons-codec-1.15.jar.sha1 b/client/sniffer/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/client/sniffer/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/client/sniffer/licenses/commons-logging-1.1.3.jar.sha1 b/client/sniffer/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index 5b8f029e58293..0000000000000
--- a/client/sniffer/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
\ No newline at end of file
diff --git a/client/sniffer/licenses/commons-logging-1.2.jar.sha1 b/client/sniffer/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/client/sniffer/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/client/sniffer/licenses/httpclient-4.5.13.jar.sha1 b/client/sniffer/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/client/sniffer/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/client/sniffer/licenses/httpclient-4.5.14.jar.sha1 b/client/sniffer/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/client/sniffer/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/client/sniffer/licenses/httpcore-4.4.12.jar.sha1 b/client/sniffer/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/client/sniffer/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/client/sniffer/licenses/httpcore-4.4.16.jar.sha1 b/client/sniffer/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/client/sniffer/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/client/sniffer/licenses/jackson-core-2.13.2.jar.sha1 b/client/sniffer/licenses/jackson-core-2.13.2.jar.sha1
deleted file mode 100644
index eb8a8bc45f041..0000000000000
--- a/client/sniffer/licenses/jackson-core-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0a6a0e0620d51833feffc67bccb51937b2345763
\ No newline at end of file
diff --git a/client/sniffer/licenses/jackson-core-2.15.2.jar.sha1 b/client/sniffer/licenses/jackson-core-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..ec6781b968eed
--- /dev/null
+++ b/client/sniffer/licenses/jackson-core-2.15.2.jar.sha1
@@ -0,0 +1 @@
+a6fe1836469a69b3ff66037c324d75fc66ef137c
\ No newline at end of file
diff --git a/client/sniffer/src/main/java/org/opensearch/client/sniff/OpenSearchNodesSniffer.java b/client/sniffer/src/main/java/org/opensearch/client/sniff/OpenSearchNodesSniffer.java
index 2829439627dbc..63fd6c336cfc8 100644
--- a/client/sniffer/src/main/java/org/opensearch/client/sniff/OpenSearchNodesSniffer.java
+++ b/client/sniffer/src/main/java/org/opensearch/client/sniff/OpenSearchNodesSniffer.java
@@ -35,6 +35,7 @@
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonToken;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.HttpEntity;
@@ -49,6 +50,7 @@
 import java.io.InputStream;
 import java.net.URI;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -241,74 +243,23 @@ private static Node readNode(String nodeId, JsonParser parser, Scheme scheme) th
         }
 
         Map<String, List<String>> realAttributes = new HashMap<>(protoAttributes.size());
-        List<String> keys = new ArrayList<>(protoAttributes.keySet());
-        for (String key : keys) {
-            if (key.endsWith(".0")) {
-                String realKey = key.substring(0, key.length() - 2);
-                List<String> values = new ArrayList<>();
-                int i = 0;
-                while (true) {
-                    String value = protoAttributes.remove(realKey + "." + i);
-                    if (value == null) {
-                        break;
-                    }
-                    values.add(value);
-                    i++;
-                }
-                realAttributes.put(realKey, unmodifiableList(values));
-            }
-        }
         for (Map.Entry<String, String> entry : protoAttributes.entrySet()) {
-            realAttributes.put(entry.getKey(), singletonList(entry.getValue()));
-        }
-
-        if (version.startsWith("2.")) {
-            /*
-             * 2.x doesn't send roles, instead we try to read them from
-             * attributes.
-             */
-            boolean clientAttribute = v2RoleAttributeValue(realAttributes, "client", false);
-            Boolean masterAttribute = v2RoleAttributeValue(realAttributes, "master", null);
-            Boolean dataAttribute = v2RoleAttributeValue(realAttributes, "data", null);
-            if ((masterAttribute == null && false == clientAttribute) || masterAttribute) {
-                roles.add("master");
-            }
-            if ((dataAttribute == null && false == clientAttribute) || dataAttribute) {
-                roles.add("data");
+            if (entry.getValue().startsWith("[")) {
+                // Convert string array to list
+                String value = entry.getValue();
+                String[] values = value.substring(1, value.length() - 1).split(", ");
+                realAttributes.put(entry.getKey(), unmodifiableList(Arrays.asList(values)));
+            } else {
+                realAttributes.put(entry.getKey(), singletonList(entry.getValue()));
             }
-        } else {
-            assert sawRoles : "didn't see roles for [" + nodeId + "]";
         }
+
+        assert sawRoles : "didn't see roles for [" + nodeId + "]";
         assert boundHosts.contains(publishedHost) : "[" + nodeId + "] doesn't make sense! publishedHost should be in boundHosts";
         logger.trace("adding node [" + nodeId + "]");
         return new Node(publishedHost, boundHosts, name, version, new Roles(roles), unmodifiableMap(realAttributes));
     }
 
-    /**
-     * Returns {@code defaultValue} if the attribute didn't come back,
-     * {@code true} or {@code false} if it did come back as
-     * either of those, or throws an IOException if the attribute
-     * came back in a strange way.
-     */
-    private static Boolean v2RoleAttributeValue(Map<String, List<String>> attributes, String name, Boolean defaultValue)
-        throws IOException {
-        List<String> valueList = attributes.remove(name);
-        if (valueList == null) {
-            return defaultValue;
-        }
-        if (valueList.size() != 1) {
-            throw new IOException("expected only a single attribute value for [" + name + "] but got " + valueList);
-        }
-        switch (valueList.get(0)) {
-            case "true":
-                return true;
-            case "false":
-                return false;
-            default:
-                throw new IOException("expected [" + name + "] to be either [true] or [false] but was [" + valueList.get(0) + "]");
-        }
-    }
-
     /**
      * The supported host schemes.
      */
diff --git a/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferParseTests.java b/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferParseTests.java
index a9ff47eab5366..615e63fdaca37 100644
--- a/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferParseTests.java
+++ b/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferParseTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.client.sniff;
 
 import com.fasterxml.jackson.core.JsonFactory;
+
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
 import org.apache.http.entity.ContentType;
@@ -45,8 +46,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -85,59 +86,31 @@ private void checkFile(String file, Node... expected) throws IOException {
         }
     }
 
-    public void test2x() throws IOException {
-        checkFile(
-            "2.0.0_nodes_http.json",
-            node(9200, "m1", "2.0.0", true, false, false),
-            node(9201, "m2", "2.0.0", true, true, false),
-            node(9202, "m3", "2.0.0", true, false, false),
-            node(9203, "d1", "2.0.0", false, true, false),
-            node(9204, "d2", "2.0.0", false, true, false),
-            node(9205, "d3", "2.0.0", false, true, false),
-            node(9206, "c1", "2.0.0", false, false, false),
-            node(9207, "c2", "2.0.0", false, false, false)
-        );
-    }
-
-    public void test5x() throws IOException {
-        checkFile(
-            "5.0.0_nodes_http.json",
-            node(9200, "m1", "5.0.0", true, false, true),
-            node(9201, "m2", "5.0.0", true, true, true),
-            node(9202, "m3", "5.0.0", true, false, true),
-            node(9203, "d1", "5.0.0", false, true, true),
-            node(9204, "d2", "5.0.0", false, true, true),
-            node(9205, "d3", "5.0.0", false, true, true),
-            node(9206, "c1", "5.0.0", false, false, true),
-            node(9207, "c2", "5.0.0", false, false, true)
-        );
-    }
-
-    public void test6x() throws IOException {
+    public void test1x() throws IOException {
         checkFile(
-            "6.0.0_nodes_http.json",
-            node(9200, "m1", "6.0.0", true, false, true),
-            node(9201, "m2", "6.0.0", true, true, true),
-            node(9202, "m3", "6.0.0", true, false, true),
-            node(9203, "d1", "6.0.0", false, true, true),
-            node(9204, "d2", "6.0.0", false, true, true),
-            node(9205, "d3", "6.0.0", false, true, true),
-            node(9206, "c1", "6.0.0", false, false, true),
-            node(9207, "c2", "6.0.0", false, false, true)
+            "1.0.0_nodes_http.json",
+            node(9200, "m1", "1.0.0", "master", "ingest"),
+            node(9201, "m2", "1.0.0", "master", "data", "ingest"),
+            node(9202, "m3", "1.0.0", "master", "ingest"),
+            node(9203, "d1", "1.0.0", "data", "ingest"),
+            node(9204, "d2", "1.0.0", "data", "ingest"),
+            node(9205, "d3", "1.0.0", "data", "ingest"),
+            node(9206, "c1", "1.0.0", "ingest"),
+            node(9207, "c2", "1.0.0", "ingest")
         );
     }
 
-    public void test7x() throws IOException {
+    public void test2x() throws IOException {
         checkFile(
-            "7.3.0_nodes_http.json",
-            node(9200, "m1", "7.3.0", "master", "ingest"),
-            node(9201, "m2", "7.3.0", "master", "data", "ingest"),
-            node(9202, "m3", "7.3.0", "master", "ingest"),
-            node(9203, "d1", "7.3.0", "data", "ingest", "ml"),
-            node(9204, "d2", "7.3.0", "data", "ingest"),
-            node(9205, "d3", "7.3.0", "data", "ingest"),
-            node(9206, "c1", "7.3.0", "ingest"),
-            node(9207, "c2", "7.3.0", "ingest")
+            "2.0.0_nodes_http.json",
+            node(9200, "m1", "2.0.0", "cluster_manager", "ingest"),
+            node(9201, "m2", "2.0.0", "cluster_manager", "data", "ingest"),
+            node(9202, "m3", "2.0.0", "cluster_manager", "ingest"),
+            node(9203, "d1", "2.0.0", "data", "ingest"),
+            node(9204, "d2", "2.0.0", "data", "ingest"),
+            node(9205, "d3", "2.0.0", "data", "ingest"),
+            node(9206, "c1", "2.0.0", "ingest"),
+            node(9207, "c2", "2.0.0", "ingest")
         );
     }
 
@@ -163,20 +136,6 @@ public void testParsingPublishAddressWithES7Format() throws IOException {
         assertEquals("http", nodes.get(0).getHost().getSchemeName());
     }
 
-    private Node node(int port, String name, String version, boolean master, boolean data, boolean ingest) {
-        final Set<String> roles = new TreeSet<>();
-        if (master) {
-            roles.add("master");
-        }
-        if (data) {
-            roles.add("data");
-        }
-        if (ingest) {
-            roles.add("ingest");
-        }
-        return node(port, name, version, roles);
-    }
-
     private Node node(int port, String name, String version, String... roles) {
         return node(port, name, version, new TreeSet<>(Arrays.asList(roles)));
     }
@@ -184,11 +143,15 @@ private Node node(int port, String name, String version, String... roles) {
     private Node node(int port, String name, String version, Set<String> roles) {
         HttpHost host = new HttpHost("127.0.0.1", port);
         Set<HttpHost> boundHosts = new HashSet<>(2);
-        boundHosts.add(host);
         boundHosts.add(new HttpHost("[::1]", port));
-        Map<String, List<String>> attributes = new HashMap<>();
+        boundHosts.add(host);
+        Map<String, List<String>> attributes = new LinkedHashMap<>(); // LinkedHashMap to preserve insertion order
         attributes.put("dummy", singletonList("everyone_has_me"));
         attributes.put("number", singletonList(name.substring(1)));
+        if (!version.startsWith("1.0") && !version.startsWith("1.1")) {
+            // Shard Indexing Pressure feature is added in version 1.2.0
+            attributes.put("shard_indexing_pressure_enabled", singletonList(Boolean.TRUE.toString()));
+        }
         attributes.put("array", Arrays.asList(name.substring(0, 1), name.substring(1)));
         return new Node(host, boundHosts, name, version, new Roles(new TreeSet<>(roles)), attributes);
     }
diff --git a/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferTests.java b/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferTests.java
index 993844524c2d1..f9e658c3005ea 100644
--- a/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferTests.java
+++ b/client/sniffer/src/test/java/org/opensearch/client/sniff/OpenSearchNodesSnifferTests.java
@@ -35,11 +35,14 @@
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
+
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.Consts;
 import org.apache.http.HttpHost;
 import org.apache.http.client.methods.HttpGet;
@@ -234,7 +237,7 @@ private static SniffResponse buildSniffResponse(OpenSearchNodesSniffer.Scheme sc
 
             final Set<String> nodeRoles = new TreeSet<>();
             if (randomBoolean()) {
-                nodeRoles.add("master");
+                nodeRoles.add("cluster_manager");
             }
             if (randomBoolean()) {
                 nodeRoles.add("data");
@@ -283,12 +286,12 @@ private static SniffResponse buildSniffResponse(OpenSearchNodesSniffer.Scheme sc
                 generator.writeEndObject();
             }
 
-            List<String> roles = Arrays.asList(new String[] { "master", "data", "ingest" });
+            List<String> roles = Arrays.asList(new String[] { "cluster_manager", "data", "ingest" });
             Collections.shuffle(roles, getRandom());
             generator.writeArrayFieldStart("roles");
             for (String role : roles) {
-                if ("master".equals(role) && node.getRoles().isMasterEligible()) {
-                    generator.writeString("master");
+                if ("cluster_manager".equals(role) && node.getRoles().isClusterManagerEligible()) {
+                    generator.writeString("cluster_manager");
                 }
                 if ("data".equals(role) && node.getRoles().isData()) {
                     generator.writeString("data");
@@ -307,13 +310,7 @@ private static SniffResponse buildSniffResponse(OpenSearchNodesSniffer.Scheme sc
             if (numAttributes > 0) {
                 generator.writeObjectFieldStart("attributes");
                 for (Map.Entry<String, List<String>> entry : attributes.entrySet()) {
-                    if (entry.getValue().size() == 1) {
-                        generator.writeStringField(entry.getKey(), entry.getValue().get(0));
-                    } else {
-                        for (int v = 0; v < entry.getValue().size(); v++) {
-                            generator.writeStringField(entry.getKey() + "." + v, entry.getValue().get(v));
-                        }
-                    }
+                    generator.writeStringField(entry.getKey(), entry.getValue().toString());
                 }
                 generator.writeEndObject();
             }
diff --git a/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferBuilderTests.java b/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferBuilderTests.java
index 25a3162e238ed..78650bad01643 100644
--- a/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferBuilderTests.java
+++ b/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferBuilderTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.client.sniff;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.http.HttpHost;
 import org.opensearch.client.RestClient;
 import org.opensearch.client.RestClientTestCase;
diff --git a/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferTests.java b/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferTests.java
index 304243e73c078..b73e4401ce60c 100644
--- a/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferTests.java
+++ b/client/sniffer/src/test/java/org/opensearch/client/sniff/SnifferTests.java
@@ -38,8 +38,6 @@
 import org.opensearch.client.RestClientTestCase;
 import org.opensearch.client.sniff.Sniffer.DefaultScheduler;
 import org.opensearch.client.sniff.Sniffer.Scheduler;
-import org.mockito.invocation.InvocationOnMock;
-import org.mockito.stubbing.Answer;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -61,6 +59,9 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.Matchers.greaterThan;
diff --git a/client/sniffer/src/test/java/org/opensearch/client/sniff/documentation/SnifferDocumentation.java b/client/sniffer/src/test/java/org/opensearch/client/sniff/documentation/SnifferDocumentation.java
index 3b612aab80851..e337e8930ad2a 100644
--- a/client/sniffer/src/test/java/org/opensearch/client/sniff/documentation/SnifferDocumentation.java
+++ b/client/sniffer/src/test/java/org/opensearch/client/sniff/documentation/SnifferDocumentation.java
@@ -35,8 +35,8 @@
 import org.apache.http.HttpHost;
 import org.opensearch.client.Node;
 import org.opensearch.client.RestClient;
-import org.opensearch.client.sniff.OpenSearchNodesSniffer;
 import org.opensearch.client.sniff.NodesSniffer;
+import org.opensearch.client.sniff.OpenSearchNodesSniffer;
 import org.opensearch.client.sniff.SniffOnFailureListener;
 import org.opensearch.client.sniff.Sniffer;
 
diff --git a/client/sniffer/src/test/resources/1.0.0_nodes_http.json b/client/sniffer/src/test/resources/1.0.0_nodes_http.json
new file mode 100644
index 0000000000000..5557f0c7955c2
--- /dev/null
+++ b/client/sniffer/src/test/resources/1.0.0_nodes_http.json
@@ -0,0 +1,217 @@
+{
+  "_nodes": {
+    "total": 8,
+    "successful": 8,
+    "failed": 0
+  },
+  "cluster_name": "opensearch",
+  "nodes": {
+    "ikXK_skVTfWkhONhldnbkw": {
+      "name": "m1",
+      "transport_address": "127.0.0.1:9300",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "ingest",
+        "master"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "1",
+        "array": "[m, 1]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9200",
+          "127.0.0.1:9200"
+        ],
+        "publish_address": "127.0.0.1:9200",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "TMHa34w4RqeuYoHCfJGXZg": {
+      "name": "m2",
+      "transport_address": "127.0.0.1:9301",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "data",
+        "ingest",
+        "master"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "2",
+        "array": "[m, 2]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9201",
+          "127.0.0.1:9201"
+        ],
+        "publish_address": "127.0.0.1:9201",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "lzaMRJTVT166sgVZdQ5thA": {
+      "name": "m3",
+      "transport_address": "127.0.0.1:9302",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "ingest",
+        "master"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "3",
+        "array": "[m, 3]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9202",
+          "127.0.0.1:9202"
+        ],
+        "publish_address": "127.0.0.1:9202",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "tGP5sUecSd6BLTWk1NWF8Q": {
+      "name": "d1",
+      "transport_address": "127.0.0.1:9303",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "data",
+        "ingest"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "1",
+        "array": "[d, 1]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9203",
+          "127.0.0.1:9203"
+        ],
+        "publish_address": "127.0.0.1:9203",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "c1UgW5ROTkSa2YnM_T56tw": {
+      "name": "d2",
+      "transport_address": "127.0.0.1:9304",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "data",
+        "ingest"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "2",
+        "array": "[d, 2]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9204",
+          "127.0.0.1:9204"
+        ],
+        "publish_address": "127.0.0.1:9204",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "QM9yjqjmS72MstpNYV_trg": {
+      "name": "d3",
+      "transport_address": "127.0.0.1:9305",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "data",
+        "ingest"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "3",
+        "array": "[d, 3]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9205",
+          "127.0.0.1:9205"
+        ],
+        "publish_address": "127.0.0.1:9205",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "wLtzAssoQYeX_4TstgCj0Q": {
+      "name": "c1",
+      "transport_address": "127.0.0.1:9306",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "ingest"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "1",
+        "array": "[c, 1]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9206",
+          "127.0.0.1:9206"
+        ],
+        "publish_address": "127.0.0.1:9206",
+        "max_content_length_in_bytes": 104857600
+      }
+    },
+    "ONOzpst8TH-ZebG7fxGwaA": {
+      "name": "c2",
+      "transport_address": "127.0.0.1:9307",
+      "host": "127.0.0.1",
+      "ip": "127.0.0.1",
+      "version": "1.0.0",
+      "build_type": "tar",
+      "build_hash": "34550c5b17124ddc59458ef774f6b43a086522e3",
+      "roles": [
+        "ingest"
+      ],
+      "attributes": {
+        "dummy": "everyone_has_me",
+        "number": "2",
+        "array": "[c, 2]"
+      },
+      "http": {
+        "bound_address": [
+          "[::1]:9207",
+          "127.0.0.1:9207"
+        ],
+        "publish_address": "127.0.0.1:9207",
+        "max_content_length_in_bytes": 104857600
+      }
+    }
+  }
+}
diff --git a/client/sniffer/src/test/resources/2.0.0_nodes_http.json b/client/sniffer/src/test/resources/2.0.0_nodes_http.json
index 4e8dbbcba58c4..e1b75d460d7d9 100644
--- a/client/sniffer/src/test/resources/2.0.0_nodes_http.json
+++ b/client/sniffer/src/test/resources/2.0.0_nodes_http.json
@@ -1,4 +1,9 @@
 {
+  "_nodes": {
+    "total": 8,
+    "successful": 8,
+    "failed": 0
+  },
   "cluster_name": "opensearch",
   "nodes": {
     "qr-SOrELSaGW8SlU8nflBw": {
@@ -7,20 +12,22 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9200",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "cluster_manager",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "1",
-        "array.0": "m",
-        "data": "false",
-        "array.1": "1",
-        "master": "true"
+        "array": "[m, 1]",
+        "shard_indexing_pressure_enabled": "true"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9200",
-          "[::1]:9200"
+          "[::1]:9200",
+          "127.0.0.1:9200"
         ],
         "publish_address": "127.0.0.1:9200",
         "max_content_length_in_bytes": 104857600
@@ -32,19 +39,23 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9201",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "cluster_manager",
+        "data",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "2",
-        "array.0": "m",
-        "array.1": "2",
-        "master": "true"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[m, 2]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9201",
-          "[::1]:9201"
+          "[::1]:9201",
+          "127.0.0.1:9201"
         ],
         "publish_address": "127.0.0.1:9201",
         "max_content_length_in_bytes": 104857600
@@ -56,20 +67,22 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9202",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "cluster_manager",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "3",
-        "array.0": "m",
-        "data": "false",
-        "array.1": "3",
-        "master": "true"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[m, 3]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9202",
-          "[::1]:9202"
+          "[::1]:9202",
+          "127.0.0.1:9202"
         ],
         "publish_address": "127.0.0.1:9202",
         "max_content_length_in_bytes": 104857600
@@ -81,19 +94,22 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9203",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "data",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "1",
-        "array.0": "d",
-        "array.1": "1",
-        "master": "false"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[d, 1]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9203",
-          "[::1]:9203"
+          "[::1]:9203",
+          "127.0.0.1:9203"
         ],
         "publish_address": "127.0.0.1:9203",
         "max_content_length_in_bytes": 104857600
@@ -105,19 +121,22 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9204",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "data",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "2",
-        "array.0": "d",
-        "array.1": "2",
-        "master": "false"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[d, 2]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9204",
-          "[::1]:9204"
+          "[::1]:9204",
+          "127.0.0.1:9204"
         ],
         "publish_address": "127.0.0.1:9204",
         "max_content_length_in_bytes": 104857600
@@ -129,19 +148,22 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9205",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "data",
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "3",
-        "array.0": "d",
-        "array.1": "3",
-        "master": "false"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[d, 3]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9205",
-          "[::1]:9205"
+          "[::1]:9205",
+          "127.0.0.1:9205"
         ],
         "publish_address": "127.0.0.1:9205",
         "max_content_length_in_bytes": 104857600
@@ -153,20 +175,21 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9206",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "1",
-        "array.0": "c",
-        "data": "false",
-        "array.1": "1",
-        "master": "false"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[c, 1]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9206",
-          "[::1]:9206"
+          "[::1]:9206",
+          "127.0.0.1:9206"
         ],
         "publish_address": "127.0.0.1:9206",
         "max_content_length_in_bytes": 104857600
@@ -178,20 +201,21 @@
       "host": "127.0.0.1",
       "ip": "127.0.0.1",
       "version": "2.0.0",
-      "build": "de54438",
-      "http_address": "127.0.0.1:9207",
+      "build_type": "tar",
+      "build_hash": "bae3b4e4178c20ac24fece8e82099abe3b2630d0",
+      "roles": [
+        "ingest"
+      ],
       "attributes": {
         "dummy": "everyone_has_me",
         "number": "2",
-        "array.0": "c",
-        "data": "false",
-        "array.1": "2",
-        "master": "false"
+        "shard_indexing_pressure_enabled": "true",
+        "array": "[c, 2]"
       },
       "http": {
         "bound_address": [
-          "127.0.0.1:9207",
-          "[::1]:9207"
+          "[::1]:9207",
+          "127.0.0.1:9207"
         ],
         "publish_address": "127.0.0.1:9207",
         "max_content_length_in_bytes": 104857600
diff --git a/client/sniffer/src/test/resources/5.0.0_nodes_http.json b/client/sniffer/src/test/resources/5.0.0_nodes_http.json
deleted file mode 100644
index 4eb0443bc09d8..0000000000000
--- a/client/sniffer/src/test/resources/5.0.0_nodes_http.json
+++ /dev/null
@@ -1,217 +0,0 @@
-{
-  "_nodes": {
-    "total": 8,
-    "successful": 8,
-    "failed": 0
-  },
-  "cluster_name": "opensearch",
-  "nodes": {
-    "0S4r3NurTYSFSb8R9SxwWA": {
-      "name": "m1",
-      "transport_address": "127.0.0.1:9300",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "m",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9200",
-          "127.0.0.1:9200"
-        ],
-        "publish_address": "127.0.0.1:9200",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "k_CBrMXARkS57Qb5-3Mw5g": {
-      "name": "m2",
-      "transport_address": "127.0.0.1:9301",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "master",
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "m",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9201",
-          "127.0.0.1:9201"
-        ],
-        "publish_address": "127.0.0.1:9201",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "6eynRPQ1RleJTeGDuTR9mw": {
-      "name": "m3",
-      "transport_address": "127.0.0.1:9302",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "m",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9202",
-          "127.0.0.1:9202"
-        ],
-        "publish_address": "127.0.0.1:9202",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "cbGC-ay1QNWaESvEh5513w": {
-      "name": "d1",
-      "transport_address": "127.0.0.1:9303",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "d",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9203",
-          "127.0.0.1:9203"
-        ],
-        "publish_address": "127.0.0.1:9203",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "LexndPpXR2ytYsU5fTElnQ": {
-      "name": "d2",
-      "transport_address": "127.0.0.1:9304",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "d",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9204",
-          "127.0.0.1:9204"
-        ],
-        "publish_address": "127.0.0.1:9204",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "SbNG1DKYSBu20zfOz2gDZQ": {
-      "name": "d3",
-      "transport_address": "127.0.0.1:9305",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "d",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9205",
-          "127.0.0.1:9205"
-        ],
-        "publish_address": "127.0.0.1:9205",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "fM4H-m2WTDWmsGsL7jIJew": {
-      "name": "c1",
-      "transport_address": "127.0.0.1:9306",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "c",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9206",
-          "127.0.0.1:9206"
-        ],
-        "publish_address": "127.0.0.1:9206",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "pFoh7d0BTbqqI3HKd9na5A": {
-      "name": "c2",
-      "transport_address": "127.0.0.1:9307",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "5.0.0",
-      "build_hash": "253032b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "c",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9207",
-          "127.0.0.1:9207"
-        ],
-        "publish_address": "127.0.0.1:9207",
-        "max_content_length_in_bytes": 104857600
-      }
-    }
-  }
-}
diff --git a/client/sniffer/src/test/resources/6.0.0_nodes_http.json b/client/sniffer/src/test/resources/6.0.0_nodes_http.json
deleted file mode 100644
index adc8f535d6aad..0000000000000
--- a/client/sniffer/src/test/resources/6.0.0_nodes_http.json
+++ /dev/null
@@ -1,217 +0,0 @@
-{
-  "_nodes": {
-    "total": 8,
-    "successful": 8,
-    "failed": 0
-  },
-  "cluster_name": "opensearch",
-  "nodes": {
-    "ikXK_skVTfWkhONhldnbkw": {
-      "name": "m1",
-      "transport_address": "127.0.0.1:9300",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "m",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9200",
-          "127.0.0.1:9200"
-        ],
-        "publish_address": "127.0.0.1:9200",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "TMHa34w4RqeuYoHCfJGXZg": {
-      "name": "m2",
-      "transport_address": "127.0.0.1:9301",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "m",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9201",
-          "127.0.0.1:9201"
-        ],
-        "publish_address": "127.0.0.1:9201",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "lzaMRJTVT166sgVZdQ5thA": {
-      "name": "m3",
-      "transport_address": "127.0.0.1:9302",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "m",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9202",
-          "127.0.0.1:9202"
-        ],
-        "publish_address": "127.0.0.1:9202",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "tGP5sUecSd6BLTWk1NWF8Q": {
-      "name": "d1",
-      "transport_address": "127.0.0.1:9303",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "d",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9203",
-          "127.0.0.1:9203"
-        ],
-        "publish_address": "127.0.0.1:9203",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "c1UgW5ROTkSa2YnM_T56tw": {
-      "name": "d2",
-      "transport_address": "127.0.0.1:9304",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "d",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9204",
-          "127.0.0.1:9204"
-        ],
-        "publish_address": "127.0.0.1:9204",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "QM9yjqjmS72MstpNYV_trg": {
-      "name": "d3",
-      "transport_address": "127.0.0.1:9305",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "d",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9205",
-          "127.0.0.1:9205"
-        ],
-        "publish_address": "127.0.0.1:9205",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "wLtzAssoQYeX_4TstgCj0Q": {
-      "name": "c1",
-      "transport_address": "127.0.0.1:9306",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "c",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9206",
-          "127.0.0.1:9206"
-        ],
-        "publish_address": "127.0.0.1:9206",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "ONOzpst8TH-ZebG7fxGwaA": {
-      "name": "c2",
-      "transport_address": "127.0.0.1:9307",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "6.0.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "c",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9207",
-          "127.0.0.1:9207"
-        ],
-        "publish_address": "127.0.0.1:9207",
-        "max_content_length_in_bytes": 104857600
-      }
-    }
-  }
-}
diff --git a/client/sniffer/src/test/resources/7.3.0_nodes_http.json b/client/sniffer/src/test/resources/7.3.0_nodes_http.json
deleted file mode 100644
index 9e85511fadb62..0000000000000
--- a/client/sniffer/src/test/resources/7.3.0_nodes_http.json
+++ /dev/null
@@ -1,218 +0,0 @@
-{
-  "_nodes": {
-    "total": 8,
-    "successful": 8,
-    "failed": 0
-  },
-  "cluster_name": "opensearch",
-  "nodes": {
-    "ikXK_skVTfWkhONhldnbkw": {
-      "name": "m1",
-      "transport_address": "127.0.0.1:9300",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "m",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9200",
-          "127.0.0.1:9200"
-        ],
-        "publish_address": "127.0.0.1:9200",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "TMHa34w4RqeuYoHCfJGXZg": {
-      "name": "m2",
-      "transport_address": "127.0.0.1:9301",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "m",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9201",
-          "127.0.0.1:9201"
-        ],
-        "publish_address": "127.0.0.1:9201",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "lzaMRJTVT166sgVZdQ5thA": {
-      "name": "m3",
-      "transport_address": "127.0.0.1:9302",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "master",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "m",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9202",
-          "127.0.0.1:9202"
-        ],
-        "publish_address": "127.0.0.1:9202",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "tGP5sUecSd6BLTWk1NWF8Q": {
-      "name": "d1",
-      "transport_address": "127.0.0.1:9303",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest",
-        "ml"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "d",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9203",
-          "127.0.0.1:9203"
-        ],
-        "publish_address": "127.0.0.1:9203",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "c1UgW5ROTkSa2YnM_T56tw": {
-      "name": "d2",
-      "transport_address": "127.0.0.1:9304",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "d",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9204",
-          "127.0.0.1:9204"
-        ],
-        "publish_address": "127.0.0.1:9204",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "QM9yjqjmS72MstpNYV_trg": {
-      "name": "d3",
-      "transport_address": "127.0.0.1:9305",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "data",
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "3",
-        "array.0": "d",
-        "array.1": "3"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9205",
-          "127.0.0.1:9205"
-        ],
-        "publish_address": "127.0.0.1:9205",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "wLtzAssoQYeX_4TstgCj0Q": {
-      "name": "c1",
-      "transport_address": "127.0.0.1:9306",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "1",
-        "array.0": "c",
-        "array.1": "1"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9206",
-          "127.0.0.1:9206"
-        ],
-        "publish_address": "127.0.0.1:9206",
-        "max_content_length_in_bytes": 104857600
-      }
-    },
-    "ONOzpst8TH-ZebG7fxGwaA": {
-      "name": "c2",
-      "transport_address": "127.0.0.1:9307",
-      "host": "127.0.0.1",
-      "ip": "127.0.0.1",
-      "version": "7.3.0",
-      "build_hash": "8f0685b",
-      "roles": [
-        "ingest"
-      ],
-      "attributes": {
-        "dummy": "everyone_has_me",
-        "number": "2",
-        "array.0": "c",
-        "array.1": "2"
-      },
-      "http": {
-        "bound_address": [
-          "[::1]:9207",
-          "127.0.0.1:9207"
-        ],
-        "publish_address": "127.0.0.1:9207",
-        "max_content_length_in_bytes": 104857600
-      }
-    }
-  }
-}
diff --git a/client/sniffer/src/test/resources/create_test_nodes_info.bash b/client/sniffer/src/test/resources/create_test_nodes_info.bash
index e5925b195057d..78e67562d815b 100644
--- a/client/sniffer/src/test/resources/create_test_nodes_info.bash
+++ b/client/sniffer/src/test/resources/create_test_nodes_info.bash
@@ -14,22 +14,18 @@
 # when we do rebuild the files they don't jump around too much. That
 # way the diffs are smaller.
 
-set -e
+set -e -o pipefail
 
 script_path="$( cd "$(dirname "$0")" ; pwd -P )"
 work=$(mktemp -d)
 pushd ${work} >> /dev/null
 echo Working in ${work}
 
-wget https://download.elasticsearch.org/elasticsearch/release/org/elasticsearch/distribution/tar/elasticsearch/2.0.0/elasticsearch-2.0.0.tar.gz
-wget https://artifacts-no-kpi.elastic.co/downloads/elasticsearch/elasticsearch-5.0.0.tar.gz
-wget https://artifacts-no-kpi.elastic.co/downloads/elasticsearch/elasticsearch-6.0.0.tar.gz
-sha1sum -c - << __SHAs
-e369d8579bd3a2e8b5344278d5043f19f14cac88 elasticsearch-2.0.0.tar.gz
-d25f6547bccec9f0b5ea7583815f96a6f50849e0 elasticsearch-5.0.0.tar.gz
-__SHAs
+wget https://artifacts.opensearch.org/releases/core/opensearch/1.0.0/opensearch-min-1.0.0-linux-x64.tar.gz
+wget https://artifacts.opensearch.org/releases/core/opensearch/2.0.0/opensearch-min-2.0.0-linux-x64.tar.gz
 sha512sum -c - << __SHAs
-25bb622d2fc557d8b8eded634a9b333766f7b58e701359e1bcfafee390776eb323cb7ea7a5e02e8803e25d8b1d3aabec0ec1b0cf492d0bab5689686fe440181c elasticsearch-6.0.0.tar.gz
+96595cd3b173188d8a3f0f18d7bfa2457782839d06b519f01a99b4dc0280f81b08ba1d01bd1aef454feaa574cbbd04d3ad9a1f6a829182627e914f3e58f2899f opensearch-min-1.0.0-linux-x64.tar.gz
+5b91456a2eb517bc48f13bec0a3f9c220494bd5fe979946dce6cfc3fa7ca00b003927157194d62f2a1c36c850eda74c70b93fbffa91bb082b2e1a17985d50976 opensearch-min-2.0.0-linux-x64.tar.gz
 __SHAs
 
 
@@ -40,37 +36,38 @@ function do_version() {
     mkdir -p ${version}
     pushd ${version} >> /dev/null
 
-    tar xf ../opensearch-${version}.tar.gz
+    tar xf ../opensearch-min-${version}-linux-x64.tar.gz
     local http_port=9200
     for node in ${nodes}; do
         mkdir ${node}
         cp -r opensearch-${version}/* ${node}
-        local master=$([[ "$node" =~ ^m.* ]] && echo true || echo false)
-        local data=$([[ "$node" =~ ^d.* ]] && echo true || echo false)
-        # m2 is always master and data for these test just so we have a node like that
-        data=$([[ "$node" == 'm2' ]] && echo true || echo ${data})
-        local attr=$([ ${version} == '2.0.0' ] && echo '' || echo '.attr')
+        local cluster_manager=$([[ "$node" =~ ^m.* ]] && echo 'cluster_manager,' || echo '')
+        # 'cluster_manager' role is add in version 2.x and above, use 'master' role in 1.x
+        cluster_manager=$([[ ! "$cluster_manager" == '' && ${version} =~ ^1\. ]] && echo 'master,' || echo ${cluster_manager})
+        local data=$([[ "$node" =~ ^d.* ]] && echo 'data,' || echo '')
+        # m2 is always cluster_manager and data for these test just so we have a node like that
+        data=$([[ "$node" == 'm2' ]] && echo 'data,' || echo ${data})
+        # setting name 'cluster.initial_cluster_manager_nodes' is add in version 2.x and above
+        local initial_cluster_manager_nodes=$([[ ${version} =~ ^1\. ]] && echo 'initial_master_nodes' || echo 'initial_cluster_manager_nodes')
         local transport_port=$((http_port+100))
 
-        cat >> ${node}/config/opensearch.yml << __ES_YML
+        cat >> ${node}/config/opensearch.yml << __OPENSEARCH_YML
 node.name:          ${node}
-node.master:        ${master}
-node.data:          ${data}
-node${attr}.dummy:  everyone_has_me
-node${attr}.number: ${node:1}
-node${attr}.array:  [${node:0:1}, ${node:1}]
+node.roles:         [${cluster_manager} ${data} ingest]
+node.attr.dummy:    everyone_has_me
+node.attr.number:   ${node:1}
+node.attr.array:    [${node:0:1}, ${node:1}]
 http.port:          ${http_port}
 transport.tcp.port: ${transport_port}
-discovery.zen.minimum_master_nodes: 3
-discovery.zen.ping.unicast.hosts: ['localhost:9300','localhost:9301','localhost:9302']
-__ES_YML
+cluster.${initial_cluster_manager_nodes}: [m1, m2, m3]
+discovery.seed_hosts: ['localhost:9300','localhost:9301','localhost:9302']
+__OPENSEARCH_YML
 
-        if [ ${version} != '2.0.0' ]; then
-            perl -pi -e 's/-Xm([sx]).+/-Xm${1}512m/g' ${node}/config/jvm.options
-        fi
+        # configure the JVM heap size
+        perl -pi -e 's/-Xm([sx]).+/-Xm${1}512m/g' ${node}/config/jvm.options
 
         echo "starting ${version}/${node}..."
-        ${node}/bin/opensearch -d -p ${node}/pidfile
+        ${node}/bin/opensearch -d -p pidfile
 
         ((http_port++))
     done
@@ -99,9 +96,8 @@ __ES_YML
     popd >> /dev/null
 }
 
-JAVA_HOME=$JAVA8_HOME do_version 2.0.0
-JAVA_HOME=$JAVA8_HOME do_version 5.0.0
-JAVA_HOME=$JAVA8_HOME do_version 6.0.0
+JAVA_HOME=$JAVA11_HOME do_version 1.0.0
+JAVA_HOME=$JAVA11_HOME do_version 2.0.0
 
 popd >> /dev/null
 rm -rf ${work}
diff --git a/client/test/build.gradle b/client/test/build.gradle
index 07d874cf01ea7..811ac585409dc 100644
--- a/client/test/build.gradle
+++ b/client/test/build.gradle
@@ -29,10 +29,14 @@
  */
 apply plugin: 'opensearch.build'
 
-targetCompatibility = JavaVersion.VERSION_11
-sourceCompatibility = JavaVersion.VERSION_11
+java {
+  targetCompatibility = JavaVersion.VERSION_11
+  sourceCompatibility = JavaVersion.VERSION_11
+}
 
-group = "${group}.client.test"
+base {
+  group = "${group}.client.test"
+}
 
 dependencies {
   api "org.apache.httpcomponents:httpcore:${versions.httpcore}"
diff --git a/client/test/src/main/java/org/opensearch/client/RestClientTestCase.java b/client/test/src/main/java/org/opensearch/client/RestClientTestCase.java
index 2b3e867929e27..28b74c14d929b 100644
--- a/client/test/src/main/java/org/opensearch/client/RestClientTestCase.java
+++ b/client/test/src/main/java/org/opensearch/client/RestClientTestCase.java
@@ -43,6 +43,7 @@
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope;
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakZombies;
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
+
 import org.apache.http.Header;
 
 import java.util.ArrayList;
diff --git a/client/test/src/main/java/org/opensearch/client/RestClientTestUtil.java b/client/test/src/main/java/org/opensearch/client/RestClientTestUtil.java
index aeba9bde4bff4..786302d9142cf 100644
--- a/client/test/src/main/java/org/opensearch/client/RestClientTestUtil.java
+++ b/client/test/src/main/java/org/opensearch/client/RestClientTestUtil.java
@@ -35,6 +35,7 @@
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.http.Header;
 import org.apache.http.message.BasicHeader;
 
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000000000..dac8f30956846
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,16 @@
+codecov:
+  require_ci_to_pass: yes
+
+ignore:
+  - "test"
+  - "benchmarks"
+
+coverage:
+  precision: 2
+  round: down
+  range: "70...100"
+  status:
+    project:
+      default:
+        target: 70%    # the required coverage value
+        threshold: 1%  # the leniency in hitting the target
diff --git a/dev-tools/atomic_push.sh b/dev-tools/atomic_push.sh
index d1b735f15374e..533fc5f6ed0b4 100755
--- a/dev-tools/atomic_push.sh
+++ b/dev-tools/atomic_push.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -e -o pipefail
 
 if [ "$#" -eq 0 ]; then
     printf 'Usage: %s <origin> <branch> <branch> ...\n' "$(basename "$0")"
diff --git a/dev-tools/prepare_release_update_documentation.py b/dev-tools/prepare_release_update_documentation.py
index c7eae4eeb3245..d4edbb110f278 100644
--- a/dev-tools/prepare_release_update_documentation.py
+++ b/dev-tools/prepare_release_update_documentation.py
@@ -136,4 +136,3 @@ def callback(line):
     print('WARNING: no documentation references updates for release %s' % (release_version))
 
   print('*** Done.')
-
diff --git a/dev-tools/signoff-check.sh b/dev-tools/signoff-check.sh
index 56cb49455165e..539301a1cd79d 100755
--- a/dev-tools/signoff-check.sh
+++ b/dev-tools/signoff-check.sh
@@ -1,4 +1,6 @@
-#!/bin/sh
+#!/usr/bin/env bash
+
+set -e -o pipefail
 
 ### Script to check for signoff presents on commits
 
@@ -28,4 +30,3 @@ done
 
 # Return non-zero error code if any commits were missing signoff
 exit $missingSignoff
-
diff --git a/distribution/README.md b/distribution/README.md
new file mode 100644
index 0000000000000..b9e948b625659
--- /dev/null
+++ b/distribution/README.md
@@ -0,0 +1,12 @@
+# Distributions
+This subproject contains the necessary tooling to build the various distributions.
+Note that some of this can only be run on the specific architecture and does not support cross-compile.
+
+The following distributions are being built:
+* Archives (`*.zip`, `*.tar`): these form the basis for all other OpenSearch distributions
+* Packages (`*.deb`, `*.rpm`): specific package formats for some Linux distributions
+* Docker images
+* Backwards compatibility tests: used internally for version compatibility testing, not for public consumption
+
+## With or Without JDK?
+For each supported platform there should be both a target bundled with a JDK and a target without a bundled JDK.
diff --git a/distribution/archives/build.gradle b/distribution/archives/build.gradle
index ac70ee04444c7..161b8008525b4 100644
--- a/distribution/archives/build.gradle
+++ b/distribution/archives/build.gradle
@@ -28,9 +28,11 @@
  * under the License.
  */
 
+import org.opensearch.gradle.JavaPackageType 
+
 apply plugin: 'opensearch.internal-distribution-archive-setup'
 
-CopySpec archiveFiles(CopySpec modulesFiles, String distributionType, String platform, String architecture, boolean jdk) {
+CopySpec archiveFiles(CopySpec modulesFiles, String distributionType, String platform, String architecture, JavaPackageType java) {
   return copySpec {
     into("opensearch-${version}") {
       into('lib') {
@@ -39,19 +41,23 @@ CopySpec archiveFiles(CopySpec modulesFiles, String distributionType, String pla
       into('config') {
         dirMode 0750
         fileMode 0660
-        with configFiles(distributionType, jdk)
+        with configFiles(distributionType, java)
         from {
           dirMode 0750
           jvmOptionsDir.getParent()
         }
       }
       into('bin') {
-        with binFiles(distributionType, jdk)
+        with binFiles(distributionType, java)
       }
-      if (jdk) {
+      if (java == JavaPackageType.JDK) {
         into("darwin".equals(platform) ? 'jdk.app' : 'jdk') {
           with jdkFiles(project, platform, architecture)
         }
+      } else if (java == JavaPackageType.JRE) {
+        into("darwin".equals(platform) ? 'jre.app' : 'jre') {
+          with jreFiles(project, platform, architecture)
+        }
       }
       into('') {
         from {
@@ -73,7 +79,7 @@ CopySpec archiveFiles(CopySpec modulesFiles, String distributionType, String pla
         rename { 'LICENSE.txt' }
       }
 
-      with noticeFile(jdk)
+      with noticeFile(java)
       into('modules') {
         with modulesFiles
       }
@@ -84,84 +90,122 @@ CopySpec archiveFiles(CopySpec modulesFiles, String distributionType, String pla
 distribution_archives {
   integTestZip {
     content {
-      archiveFiles(transportModulesFiles, 'zip', null, 'x64', false)
+      archiveFiles(transportModulesFiles, 'zip', null, 'x64', JavaPackageType.NONE)
     }
   }
 
   darwinTar {
     archiveClassifier = 'darwin-x64'
     content {
-      archiveFiles(modulesFiles('darwin-x64'), 'tar', 'darwin', 'x64', true)
+      archiveFiles(modulesFiles('darwin-x64'), 'tar', 'darwin', 'x64', JavaPackageType.JDK)
     }
   }
 
   darwinArm64Tar {
     archiveClassifier = 'darwin-arm64'
     content {
-      archiveFiles(modulesFiles('darwin-arm64'), 'tar', 'darwin', 'arm64', true)
+      archiveFiles(modulesFiles('darwin-arm64'), 'tar', 'darwin', 'arm64', JavaPackageType.JDK)
     }
   }
 
   noJdkDarwinTar {
     archiveClassifier = 'no-jdk-darwin-x64'
     content {
-      archiveFiles(modulesFiles('darwin-x64'), 'tar', 'darwin', 'x64', false)
+      archiveFiles(modulesFiles('darwin-x64'), 'tar', 'darwin', 'x64', JavaPackageType.NONE)
     }
   }
 
   noJdkDarwinArm64Tar {
     archiveClassifier = 'no-jdk-darwin-arm64'
     content {
-      archiveFiles(modulesFiles('darwin-arm64'), 'tar', 'darwin', 'arm64', false)
+      archiveFiles(modulesFiles('darwin-arm64'), 'tar', 'darwin', 'arm64', JavaPackageType.NONE)
     }
   }
 
   freebsdTar {
     archiveClassifier = 'freebsd-x64'
     content {
-      archiveFiles(modulesFiles('freebsd-x64'), 'tar', 'freebsd', 'x64', false)
+      archiveFiles(modulesFiles('freebsd-x64'), 'tar', 'freebsd', 'x64', JavaPackageType.NONE)
     }
   }
 
   noJdkFreebsdTar {
     archiveClassifier = 'no-jdk-freebsd-x64'
     content {
-      archiveFiles(modulesFiles('freebsd-x64'), 'tar', 'freebsd', 'x64', false)
+      archiveFiles(modulesFiles('freebsd-x64'), 'tar', 'freebsd', 'x64', JavaPackageType.NONE)
     }
   }
 
   linuxArm64Tar {
     archiveClassifier = 'linux-arm64'
     content {
-      archiveFiles(modulesFiles('linux-arm64'), 'tar', 'linux', 'arm64', true)
+      archiveFiles(modulesFiles('linux-arm64'), 'tar', 'linux', 'arm64', JavaPackageType.JDK)
+    }
+  }
+
+  noJdkLinuxArm64Tar {
+    archiveClassifier = 'no-jdk-linux-arm64'
+    content {
+      archiveFiles(modulesFiles('linux-arm64'), 'tar', 'linux', 'arm64', JavaPackageType.NONE)
     }
   }
 
   linuxTar {
     archiveClassifier = 'linux-x64'
     content {
-      archiveFiles(modulesFiles('linux-x64'), 'tar', 'linux', 'x64', true)
+      archiveFiles(modulesFiles('linux-x64'), 'tar', 'linux', 'x64', JavaPackageType.JDK)
     }
   }
 
   noJdkLinuxTar {
     archiveClassifier = 'no-jdk-linux-x64'
     content {
-      archiveFiles(modulesFiles('linux-x64'), 'tar', 'linux', 'x64', false)
+      archiveFiles(modulesFiles('linux-x64'), 'tar', 'linux', 'x64', JavaPackageType.NONE)
+    }
+  }
+
+  jreLinuxTar {
+    archiveClassifier = 'jre-linux-x64'
+    content {
+      archiveFiles(modulesFiles('linux-x64'), 'tar', 'linux', 'x64', JavaPackageType.JRE)
+    }
+  }
+
+  // Should really be `no-jdk-linux-s390x` as it ships without a JDK, however it seems that the build can't handle
+  // the absence of the `linux-s390x` target.
+  linuxS390xTar {
+    archiveClassifier = 'linux-s390x'
+    content {
+      archiveFiles(modulesFiles('linux-s390x'), 'tar', 'linux', 's390x', JavaPackageType.NONE)
+    }
+  }
+
+  
+  linuxPpc64leTar {
+    archiveClassifier = 'linux-ppc64le'
+    content {
+      archiveFiles(modulesFiles('linux-ppc64le'), 'tar', 'linux', 'ppc64le', JavaPackageType.JDK)
+    }
+  }
+
+ noJdkLinuxPpc64leTar {
+    archiveClassifier = 'no-jdk-linux-ppc64le'
+    content {
+      archiveFiles(modulesFiles('linux-ppc64le'), 'tar', 'linux', 'ppc64le', JavaPackageType.NONE)
     }
   }
 
   windowsZip {
     archiveClassifier = 'windows-x64'
     content {
-      archiveFiles(modulesFiles('windows-x64'), 'zip', 'windows', 'x64', true)
+      archiveFiles(modulesFiles('windows-x64'), 'zip', 'windows', 'x64', JavaPackageType.JDK)
     }
   }
 
   noJdkWindowsZip {
     archiveClassifier = 'no-jdk-windows-x64'
     content {
-      archiveFiles(modulesFiles('windows-x64'), 'zip', 'windows', 'x64', false)
+      archiveFiles(modulesFiles('windows-x64'), 'zip', 'windows', 'x64', JavaPackageType.NONE)
     }
   }
 }
diff --git a/distribution/archives/darwin-arm64-tar/build.gradle b/distribution/archives/darwin-arm64-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/darwin-arm64-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/darwin-tar/build.gradle b/distribution/archives/darwin-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/darwin-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/integ-test-zip/build.gradle b/distribution/archives/integ-test-zip/build.gradle
index 35c5a9b60b568..9418223b0a44d 100644
--- a/distribution/archives/integ-test-zip/build.gradle
+++ b/distribution/archives/integ-test-zip/build.gradle
@@ -34,8 +34,12 @@ apply plugin: 'opensearch.rest-test'
 
 // The integ-test-distribution is published to maven
 apply plugin: 'opensearch.publish'
+apply plugin: 'com.netflix.nebula.maven-publish'
 
-group = "org.opensearch.distribution.integ-test-zip"
+base {
+  group = "org.opensearch.distribution.integ-test-zip"
+  archivesBaseName = "opensearch"
+}
 
 integTest {
   dependsOn assemble
@@ -47,7 +51,6 @@ processTestResources {
 }
 
 // make the pom file name use opensearch instead of the project name
-archivesBaseName = "opensearch"
 ext.buildDist = parent.tasks.named("buildIntegTestZip")
 
 publishing {
diff --git a/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/NodeRestUsageIT.java b/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/NodeRestUsageIT.java
index cb2318351086c..59df4122713d5 100644
--- a/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/NodeRestUsageIT.java
+++ b/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/NodeRestUsageIT.java
@@ -35,7 +35,8 @@
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
 import org.opensearch.client.ResponseException;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.builder.SearchSourceBuilder;
 
@@ -171,8 +172,8 @@ public void testAggregationUsage() throws IOException {
             .aggregation(AggregationBuilders.terms("str_terms").field("str.keyword"))
             .aggregation(AggregationBuilders.terms("num_terms").field("num"))
             .aggregation(AggregationBuilders.avg("num_avg").field("num"));
-        searchRequest.setJsonEntity(Strings.toString(searchSource));
-        searchRequest.setJsonEntity(Strings.toString(searchSource));
+        searchRequest.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, searchSource));
+        searchRequest.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, searchSource));
         client().performRequest(searchRequest);
 
         searchRequest = new Request("GET", "/test/_search");
@@ -181,8 +182,8 @@ public void testAggregationUsage() throws IOException {
             .aggregation(AggregationBuilders.avg("num1").field("num"))
             .aggregation(AggregationBuilders.avg("num2").field("num"))
             .aggregation(AggregationBuilders.terms("foo").field("foo.keyword"));
-        String r = Strings.toString(searchSource);
-        searchRequest.setJsonEntity(Strings.toString(searchSource));
+        String r = Strings.toString(MediaTypeRegistry.JSON, searchSource);
+        searchRequest.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, searchSource));
         client().performRequest(searchRequest);
 
         Response response = client().performRequest(new Request("GET", "_nodes/usage"));
diff --git a/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/WaitForRefreshAndCloseIT.java b/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/WaitForRefreshAndCloseIT.java
index 37ffe32d19509..e4fc5b65e0f17 100644
--- a/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/WaitForRefreshAndCloseIT.java
+++ b/distribution/archives/integ-test-zip/src/test/java/org/opensearch/test/rest/WaitForRefreshAndCloseIT.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test.rest;
 
+import org.opensearch.common.action.ActionFuture;
 import org.apache.http.util.EntityUtils;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
diff --git a/distribution/archives/linux-arm64-tar/build.gradle b/distribution/archives/linux-arm64-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/linux-arm64-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/linux-tar/build.gradle b/distribution/archives/linux-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/linux-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/no-jdk-darwin-arm64-tar/build.gradle b/distribution/archives/no-jdk-darwin-arm64-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/no-jdk-darwin-arm64-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/no-jdk-darwin-tar/build.gradle b/distribution/archives/no-jdk-darwin-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/no-jdk-darwin-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/no-jdk-linux-tar/build.gradle b/distribution/archives/no-jdk-linux-tar/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/no-jdk-linux-tar/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/no-jdk-windows-zip/build.gradle b/distribution/archives/no-jdk-windows-zip/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/no-jdk-windows-zip/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/archives/windows-zip/build.gradle b/distribution/archives/windows-zip/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/archives/windows-zip/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/build.gradle b/distribution/build.gradle
index 356aaa269e106..bbbef40f51c57 100644
--- a/distribution/build.gradle
+++ b/distribution/build.gradle
@@ -36,6 +36,7 @@ import org.opensearch.gradle.MavenFilteringHack
 import org.opensearch.gradle.NoticeTask
 import org.opensearch.gradle.VersionProperties
 import org.opensearch.gradle.info.BuildParams
+import org.opensearch.gradle.JavaPackageType
 
 import java.nio.file.Files
 import java.nio.file.Path
@@ -217,7 +218,7 @@ ext.restTestExpansions = [
 // loop over modules to also setup cross task dependencies and increment our modules counter
 project.rootProject.subprojects.findAll { it.parent.path == ':modules' }.each { Project module ->
   if (module.name == 'systemd') {
-    // the systemd module is only included in the package distributions
+    // the systemd module is only included in the package distributions or in linux and freebsd archives
     return
   }
   File licenses = new File(module.projectDir, 'licenses')
@@ -275,15 +276,16 @@ project(':test:external-modules').subprojects.each { Project testModule ->
 configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
 
   apply plugin: 'opensearch.jdk-download'
+  apply plugin: 'opensearch.jre-download'
   apply plugin: 'opensearch.repositories'
 
   // Setup all required JDKs
   project.jdks {
     ['darwin', 'linux', 'windows'].each { platform ->
-      (platform == 'linux' || platform == 'darwin' ? ['x64', 'aarch64'] : ['x64']).each { architecture ->
-        "bundled_${platform}_${architecture}" {
+      (platform == 'linux' || platform == 'darwin' ? ['x64', 'aarch64', 's390x', 'ppc64le'] : ['x64']).each { architecture ->
+        "bundled_jdk_${platform}_${architecture}" {
           it.platform = platform
-          it.version = VersionProperties.getBundledJdk(platform)
+          it.version = VersionProperties.getBundledJdk(platform, architecture)
           it.vendor = VersionProperties.bundledJdkVendor
           it.architecture = architecture
         }
@@ -291,6 +293,20 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
     }
   }
 
+  // Setup all required JREs
+  project.jres {
+    ['darwin', 'linux', 'windows'].each { platform ->
+      (platform == 'linux' || platform == 'darwin' ? ['x64', 'aarch64', 's390x', 'ppc64le'] : ['x64']).each { architecture ->
+        "bundled_jre_${platform}_${architecture}" {
+          it.platform = platform
+          it.version = VersionProperties.getBundledJre(platform, architecture)
+          it.vendor = VersionProperties.bundledJdkVendor
+          it.architecture = architecture
+       }
+      }
+    }
+  }
+
   // TODO: the map needs to be an input of the tasks, so that when it changes, the task will re-run...
   /*****************************************************************************
    *             Properties to expand when copying packaging files             *
@@ -353,7 +369,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
           }
         }
         def buildModules = buildModulesTaskProvider
-        List excludePlatforms = ['darwin-x64', 'freebsd-x64', 'linux-x64', 'linux-arm64', 'windows-x64', 'darwin-arm64']
+        List excludePlatforms = ['darwin-x64', 'freebsd-x64', 'linux-x64', 'linux-arm64', 'linux-s390x', 'linux-ppc64le', 'windows-x64', 'darwin-arm64']
         if (platform != null) {
           excludePlatforms.remove(excludePlatforms.indexOf(platform))
         } else {
@@ -367,7 +383,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
         if (BuildParams.isSnapshotBuild()) {
           from(buildExternalTestModulesTaskProvider)
         }
-        if (project.path.startsWith(':distribution:packages')) {
+        if (project.path.startsWith(':distribution:packages') || ['freebsd-x64','linux-x64', 'linux-arm64'].contains(platform)) {
           from(buildSystemdModuleTaskProvider)
         }
       }
@@ -377,20 +393,20 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
       from buildTransportModulesTaskProvider
     }
 
-    configFiles = { distributionType, jdk ->
+    configFiles = { distributionType, java ->
       copySpec {
         with copySpec {
           // main config files, processed with distribution specific substitutions
           from '../src/config'
           exclude 'log4j2.properties' // this is handled separately below
-          MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, jdk))
+          MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, java))
         }
         from project(':distribution').buildLog4jConfig
         from project(':distribution').buildConfig
       }
     }
 
-    binFiles = { distributionType, jdk ->
+    binFiles = { distributionType, java ->
       copySpec {
         // non-windows files, for all distributions
         with copySpec {
@@ -398,7 +414,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
           exclude '*.exe'
           exclude '*.bat'
           eachFile { it.setMode(0755) }
-          MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, jdk))
+          MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, java))
         }
         // windows files, only for zip
         if (distributionType == 'zip') {
@@ -406,7 +422,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
             from '../src/bin'
             include '*.bat'
             filter(FixCrLfFilter, eol: FixCrLfFilter.CrLf.newInstance('crlf'))
-            MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, jdk))
+            MavenFilteringHack.filter(it, expansionsForDistribution(distributionType, java))
           }
           with copySpec {
             from '../src/bin'
@@ -424,12 +440,12 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
       }
     }
 
-    noticeFile = { jdk ->
+    noticeFile = { java ->
       copySpec {
         if (project.name == 'integ-test-zip') {
           from buildServerNoticeTaskProvider
         } else {
-          if (jdk) {
+          if (java != JavaPackageType.NONE) {
             from buildNoticeTaskProvider
           } else {
             from buildNoJdkNoticeTaskProvider
@@ -446,7 +462,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
         if ("arm64".equals(architecture)) {
           architecture = "aarch64"
         }
-        from project.jdks."bundled_${platform}_${architecture}"
+        from project.jdks."bundled_jdk_${platform}_${architecture}"
         exclude "demo/**"
         /*
          * The Contents/MacOS directory interferes with notarization, and is unused by our distribution, so we exclude
@@ -465,6 +481,31 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
         }
       }
     }
+    
+    jreFiles = { Project project, String platform, String architecture ->
+      return copySpec {
+        /*
+         * Jdk uses aarch64 from ARM. Translating from arm64 to aarch64 which Jdk understands.
+         */
+        if ("arm64".equals(architecture)) {
+          architecture = "aarch64"
+        }
+        from project.jres."bundled_jre_${platform}_${architecture}"
+        exclude "demo/**"
+        /*
+         * The Contents/MacOS directory interferes with notarization, and is unused by our distribution, so we exclude
+         * it from the build.
+         */
+        if ("darwin".equals(platform)) {
+          exclude "Contents/MacOS"
+        }
+        eachFile { FileCopyDetails details ->
+          if (details.relativePath.segments[-2] == 'bin' || details.relativePath.segments[-1] == 'jspawnhelper') {
+            details.mode = 0755
+          }
+        }
+      }
+    }
   }
 }
 
@@ -583,7 +624,7 @@ subprojects {
       ],
 
       'opensearch.bundled_jdk': [
-        'def': jdk ? 'true' : 'false'
+        'def': jdk != JavaPackageType.NONE ? true : false
       ],
 
       'license.name': [
diff --git a/distribution/docker/build.gradle b/distribution/docker/build.gradle
index f5d8048a06276..ad8678c608b54 100644
--- a/distribution/docker/build.gradle
+++ b/distribution/docker/build.gradle
@@ -27,11 +27,15 @@ testFixtures.useFixture()
 
 configurations {
   arm64DockerSource
+  s390xDockerSource
+  ppc64leDockerSource
   dockerSource
 }
 
 dependencies {
   arm64DockerSource project(path: ":distribution:archives:linux-arm64-tar", configuration:"default")
+  s390xDockerSource project(path: ":distribution:archives:linux-s390x-tar", configuration:"default")
+  ppc64leDockerSource project(path: ":distribution:archives:linux-ppc64le-tar", configuration:"default")
   dockerSource project(path: ":distribution:archives:linux-tar", configuration:"default")
 }
 
@@ -42,6 +46,10 @@ ext.expansions = { Architecture architecture, DockerBase base, boolean local ->
       classifier = "linux-arm64"
     } else if (architecture == Architecture.X64) {
       classifier = "linux-x64"
+    } else if (architecture == Architecture.S390X) {
+      classifier = "linux-s390x"
+    } else if (architecture == Architecture.PPC64LE) {
+      classifier = "linux-ppc64le"
     } else {
       throw new IllegalArgumentException("Unsupported architecture [" + architecture + "]")
     }
@@ -85,12 +93,16 @@ RUN curl --retry 8 -S -L \\
 private static String buildPath(Architecture architecture, DockerBase base) {
   return 'build/' +
     (architecture == Architecture.ARM64 ? 'arm64-' : '') +
+    (architecture == Architecture.S390X ? 's390x-' : '') +
+    (architecture == Architecture.PPC64LE ? 'ppc64le-' : '') +
     'docker'
 }
 
 private static String taskName(String prefix, Architecture architecture, DockerBase base, String suffix) {
   return prefix +
     (architecture == Architecture.ARM64 ? 'Arm64' : '') +
+    (architecture == Architecture.S390X ? 'S390x' : '') +
+    (architecture == Architecture.PPC64LE ? 'Ppc64le' : '') +
     suffix
 }
 
@@ -127,6 +139,10 @@ void addCopyDockerContextTask(Architecture architecture, DockerBase base) {
 
     if (architecture == Architecture.ARM64) {
       from configurations.arm64DockerSource
+    } else if (architecture == Architecture.S390X) {
+      from configurations.s390xDockerSource
+    } else if (architecture == Architecture.PPC64LE) {
+      from configurations.ppc64leDockerSource
     } else {
       from configurations.dockerSource
     }
diff --git a/distribution/docker/docker-ppc64le-export/build.gradle b/distribution/docker/docker-ppc64le-export/build.gradle
new file mode 100644
index 0000000000000..820a0cdf69dfc
--- /dev/null
+++ b/distribution/docker/docker-ppc64le-export/build.gradle
@@ -0,0 +1,12 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+*/
+
+// This file is intentionally blank. All configuration of the
+// export is done in the parent project.
diff --git a/distribution/docker/docker-s390x-export/build.gradle b/distribution/docker/docker-s390x-export/build.gradle
new file mode 100644
index 0000000000000..3506c4e39c234
--- /dev/null
+++ b/distribution/docker/docker-s390x-export/build.gradle
@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+// This file is intentionally blank. All configuration of the
+// export is done in the parent project.
diff --git a/distribution/docker/docker-test-entrypoint.sh b/distribution/docker/docker-test-entrypoint.sh
index 85a90df003ab4..1cfc62f6b02b0 100755
--- a/distribution/docker/docker-test-entrypoint.sh
+++ b/distribution/docker/docker-test-entrypoint.sh
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+set -e -o pipefail
+
 cd /usr/share/opensearch/bin/
 
 /usr/local/bin/docker-entrypoint.sh | tee > /usr/share/opensearch/logs/console.log
diff --git a/distribution/docker/src/docker/bin/docker-entrypoint.sh b/distribution/docker/src/docker/bin/docker-entrypoint.sh
index 0d6ca588d875d..33c68afce0bfc 100644
--- a/distribution/docker/src/docker/bin/docker-entrypoint.sh
+++ b/distribution/docker/src/docker/bin/docker-entrypoint.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -e -o pipefail
 
 # Files created by Elasticsearch should always be group writable too
 umask 0002
diff --git a/distribution/docker/src/docker/config/log4j2.properties b/distribution/docker/src/docker/config/log4j2.properties
index a8c54137c7fd2..761478a9fdc6e 100644
--- a/distribution/docker/src/docker/config/log4j2.properties
+++ b/distribution/docker/src/docker/config/log4j2.properties
@@ -53,3 +53,13 @@ logger.index_indexing_slowlog.name = index.indexing.slowlog.index
 logger.index_indexing_slowlog.level = trace
 logger.index_indexing_slowlog.appenderRef.index_indexing_slowlog_rolling.ref = index_indexing_slowlog_rolling
 logger.index_indexing_slowlog.additivity = false
+
+appender.task_detailslog_rolling.type = Console
+appender.task_detailslog_rolling.name = task_detailslog_rolling
+appender.task_detailslog_rolling.layout.type = OpenSearchJsonLayout
+appender.task_detailslog_rolling.layout.type_name = task_detailslog
+
+logger.task_detailslog_rolling.name = task.detailslog
+logger.task_detailslog_rolling.level = trace
+logger.task_detailslog_rolling.appenderRef.task_detailslog_rolling.ref = task_detailslog_rolling
+logger.task_detailslog_rolling.additivity = false
diff --git a/distribution/docker/src/test/resources/rest-api-spec/test/10_info.yml b/distribution/docker/src/test/resources/rest-api-spec/test/10_info.yml
index 2b0f6683a24cf..97b3b7b5d0f4d 100644
--- a/distribution/docker/src/test/resources/rest-api-spec/test/10_info.yml
+++ b/distribution/docker/src/test/resources/rest-api-spec/test/10_info.yml
@@ -7,4 +7,3 @@
   - is_true:    version
   - is_true:    version.number
   - match: { version.build_type: "docker" }
-
diff --git a/distribution/docker/src/test/resources/rest-api-spec/test/11_nodes.yml b/distribution/docker/src/test/resources/rest-api-spec/test/11_nodes.yml
index 95ea022696942..1c10166e96eeb 100644
--- a/distribution/docker/src/test/resources/rest-api-spec/test/11_nodes.yml
+++ b/distribution/docker/src/test/resources/rest-api-spec/test/11_nodes.yml
@@ -24,8 +24,8 @@
 
   - match:
       $body: |
-        /  #ip                          heap.percent        ram.percent     cpu         load_1m                load_5m                load_15m               node.role                   cluster_manager       name
-        ^  ((\d{1,3}\.){3}\d{1,3}  \s+  \d+            \s+  \d*         \s+ (-)?\d* \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)?\s+  ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) \s+ [-*x]            \s+  (\S+\s?)+     \n)+  $/
+        /  #ip                          heap.percent        ram.percent     cpu         load_1m                load_5m                load_15m               node.role               node.roles                   cluster_manager       name
+        ^  ((\d{1,3}\.){3}\d{1,3}  \s+  \d+            \s+  \d*         \s+ (-)?\d* \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)?\s+  ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) (\s+ (-|\w+(,\w+)*+))? \s+ [-*x]            \s+  (\S+\s?)+     \n)+  $/
 
   - do:
       cat.nodes:
@@ -33,8 +33,8 @@
 
   - match:
       $body: |
-        /^  ip                     \s+  heap\.percent   \s+  ram\.percent \s+ cpu      \s+ load_1m            \s+ load_5m            \s+ load_15m           \s+ node\.role              \s+  cluster_manager   \s+   name  \n
-           ((\d{1,3}\.){3}\d{1,3}  \s+  \d+             \s+  \d*          \s+ (-)?\d* \s+  ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) \s+  [-*x]             \s+   (\S+\s?)+     \n)+  $/
+        /^  ip                     \s+  heap\.percent   \s+  ram\.percent \s+ cpu      \s+ load_1m            \s+ load_5m            \s+ load_15m           \s+ node\.role           \s+ node\.roles              \s+  cluster_manager   \s+   name  \n
+           ((\d{1,3}\.){3}\d{1,3}  \s+  \d+             \s+  \d*          \s+ (-)?\d* \s+  ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) (\s+ (-|\w+(,\w+)*+ ))? \s+  [-*x]             \s+   (\S+\s?)+     \n)+  $/
 
   - do:
       cat.nodes:
@@ -123,4 +123,3 @@
   - match:
       $body: |
         /^(\S{5,}\n)+$/
-
diff --git a/distribution/packages/arm64-deb/build.gradle b/distribution/packages/arm64-deb/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/arm64-deb/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/arm64-rpm/build.gradle b/distribution/packages/arm64-rpm/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/arm64-rpm/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/build.gradle b/distribution/packages/build.gradle
index 93a82ff324835..394d47639fb0a 100644
--- a/distribution/packages/build.gradle
+++ b/distribution/packages/build.gradle
@@ -63,7 +63,7 @@ import java.util.regex.Pattern
  */
 
 plugins {
-  id "nebula.ospackage-base" version "9.1.1"
+  id "com.netflix.nebula.ospackage-base" version "11.4.0"
 }
 
 void addProcessFilesTask(String type, boolean jdk) {
@@ -213,7 +213,7 @@ Closure commonPackageConfig(String type, boolean jdk, String architecture) {
     configurationFile '/etc/opensearch/jvm.options'
     configurationFile '/etc/opensearch/log4j2.properties'
     from("${packagingFiles}") {
-      dirMode 02750
+      dirMode 0750
       into('/etc')
       permissionGroup 'opensearch'
       includeEmptyDirs true
@@ -223,7 +223,7 @@ Closure commonPackageConfig(String type, boolean jdk, String architecture) {
     }
     from("${packagingFiles}/etc/opensearch") {
       into('/etc/opensearch')
-      dirMode 02750
+      dirMode 0750
       fileMode 0660
       permissionGroup 'opensearch'
       includeEmptyDirs true
@@ -281,8 +281,8 @@ Closure commonPackageConfig(String type, boolean jdk, String architecture) {
         dirMode mode
       }
     }
-    copyEmptyDir('/var/log/opensearch', 'opensearch', 'opensearch', 02750)
-    copyEmptyDir('/var/lib/opensearch', 'opensearch', 'opensearch', 02750)
+    copyEmptyDir('/var/log/opensearch', 'opensearch', 'opensearch', 0750)
+    copyEmptyDir('/var/lib/opensearch', 'opensearch', 'opensearch', 0750)
     copyEmptyDir('/usr/share/opensearch/plugins', 'root', 'root', 0755)
 
     into '/usr/share/opensearch'
@@ -290,7 +290,7 @@ Closure commonPackageConfig(String type, boolean jdk, String architecture) {
   }
 }
 
-apply plugin: 'nebula.ospackage-base'
+apply plugin: 'com.netflix.nebula.ospackage-base'
 
 // this is package indepdendent configuration
 ospackage {
@@ -350,6 +350,10 @@ tasks.register('buildArm64Deb', Deb) {
   configure(commonDebConfig(true, 'arm64'))
 }
 
+tasks.register('buildNoJdkArm64Deb', Deb) {
+  configure(commonDebConfig(false, 'arm64'))
+}
+
 tasks.register('buildDeb', Deb) {
   configure(commonDebConfig(true, 'x64'))
 }
@@ -387,12 +391,16 @@ tasks.register('buildArm64Rpm', Rpm) {
   configure(commonRpmConfig(true, 'arm64'))
 }
 
+tasks.register('buildNoJdkArm64Rpm', Rpm) {
+  configure(commonRpmConfig(false, 'arm64'))
+}
+
 tasks.register('buildRpm', Rpm) {
   configure(commonRpmConfig(true, 'x64'))
 }
 
 tasks.register('buildNoJdkRpm', Rpm) {
-  configure(commonRpmConfig(true, 'x64'))
+  configure(commonRpmConfig(false, 'x64'))
 }
 
 Closure dpkgExists = { it -> new File('/bin/dpkg-deb').exists() || new File('/usr/bin/dpkg-deb').exists() || new File('/usr/local/bin/dpkg-deb').exists() }
diff --git a/distribution/packages/deb/build.gradle b/distribution/packages/deb/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/deb/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/no-jdk-deb/build.gradle b/distribution/packages/no-jdk-deb/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/no-jdk-deb/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/no-jdk-rpm/build.gradle b/distribution/packages/no-jdk-rpm/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/no-jdk-rpm/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/rpm/build.gradle b/distribution/packages/rpm/build.gradle
deleted file mode 100644
index bb3e3a302c8d6..0000000000000
--- a/distribution/packages/rpm/build.gradle
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-// This file is intentionally blank. All configuration of the
-// distribution is done in the parent project.
diff --git a/distribution/packages/src/common/scripts/preinst b/distribution/packages/src/common/scripts/preinst
index c13f079666467..31e5b803b1604 100644
--- a/distribution/packages/src/common/scripts/preinst
+++ b/distribution/packages/src/common/scripts/preinst
@@ -10,6 +10,8 @@
 #       $1=1       : indicates an new install
 #       $1=2       : indicates an upgrade
 
+set -e -o pipefail
+
 err_exit() {
     echo "$@" >&2
     exit 1
diff --git a/distribution/packages/src/common/systemd/systemd-entrypoint b/distribution/packages/src/common/systemd/systemd-entrypoint
index 0773bc6f1dc04..de59b4573f79a 100644
--- a/distribution/packages/src/common/systemd/systemd-entrypoint
+++ b/distribution/packages/src/common/systemd/systemd-entrypoint
@@ -1,8 +1,10 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 # This wrapper script allows SystemD to feed a file containing a passphrase into
 # the main OpenSearch startup script
 
+set -e -o pipefail
+
 if [ -n "$OPENSEARCH_KEYSTORE_PASSPHRASE_FILE" ] ; then
   exec /usr/share/opensearch/bin/opensearch "$@" < "$OPENSEARCH_KEYSTORE_PASSPHRASE_FILE"
 else
diff --git a/distribution/packages/src/deb/init.d/opensearch b/distribution/packages/src/deb/init.d/opensearch
index e5195d2d54dba..681d87df1d356 100755
--- a/distribution/packages/src/deb/init.d/opensearch
+++ b/distribution/packages/src/deb/init.d/opensearch
@@ -12,6 +12,8 @@
 # Description:       Starts opensearch using start-stop-daemon
 ### END INIT INFO
 
+set -e -o pipefail
+
 PATH=/bin:/usr/bin:/sbin:/usr/sbin
 NAME=opensearch
 DESC="OpenSearch Server"
diff --git a/distribution/packages/src/deb/lintian/opensearch b/distribution/packages/src/deb/lintian/opensearch
index 854b23131ecbc..e6db8e8c6b322 100644
--- a/distribution/packages/src/deb/lintian/opensearch
+++ b/distribution/packages/src/deb/lintian/opensearch
@@ -15,11 +15,11 @@ missing-dep-on-jarwrapper
 
 # we prefer to not make our config and log files world readable
 non-standard-file-perm etc/default/opensearch 0660 != 0644
-non-standard-dir-perm etc/opensearch/ 2750 != 0755
-non-standard-dir-perm etc/opensearch/jvm.options.d/ 2750 != 0755
+non-standard-dir-perm etc/opensearch/ 0750 != 0755
+non-standard-dir-perm etc/opensearch/jvm.options.d/ 0750 != 0755
 non-standard-file-perm etc/opensearch/*
-non-standard-dir-perm var/lib/opensearch/ 2750 != 0755
-non-standard-dir-perm var/log/opensearch/ 2750 != 0755
+non-standard-dir-perm var/lib/opensearch/ 0750 != 0755
+non-standard-dir-perm var/log/opensearch/ 0750 != 0755
 executable-is-not-world-readable etc/init.d/opensearch 0750
 non-standard-file-permissions-for-etc-init.d-script etc/init.d/opensearch 0750 != 0755
 
diff --git a/distribution/packages/src/rpm/init.d/opensearch b/distribution/packages/src/rpm/init.d/opensearch
index 12a1470e75acb..0cb9bf65796ad 100644
--- a/distribution/packages/src/rpm/init.d/opensearch
+++ b/distribution/packages/src/rpm/init.d/opensearch
@@ -16,6 +16,8 @@
 # Description: OpenSearch is a very scalable, schema-free and high-performance search solution supporting multi-tenancy and near realtime search.
 ### END INIT INFO
 
+set -e -o pipefail
+
 #
 # init.d / servicectl compatibility (openSUSE)
 #
diff --git a/distribution/src/bin/opensearch b/distribution/src/bin/opensearch
index 52087ceb8bca9..947d1167f79f2 100755
--- a/distribution/src/bin/opensearch
+++ b/distribution/src/bin/opensearch
@@ -13,6 +13,8 @@
 #
 #   OPENSEARCH_JAVA_OPTS="-Xms8g -Xmx8g" ./bin/opensearch
 
+set -e -o pipefail
+
 source "`dirname "$0"`"/opensearch-env
 
 CHECK_KEYSTORE=true
diff --git a/distribution/src/bin/opensearch-cli.bat b/distribution/src/bin/opensearch-cli.bat
index 734669e1f9349..f080346a4478a 100644
--- a/distribution/src/bin/opensearch-cli.bat
+++ b/distribution/src/bin/opensearch-cli.bat
@@ -16,7 +16,7 @@ rem use a small heap size for the CLI tools, and thus the serial collector to
 rem avoid stealing many CPU cycles; a user can override by setting OPENSEARCH_JAVA_OPTS
 set OPENSEARCH_JAVA_OPTS=-Xms4m -Xmx64m -XX:+UseSerialGC %OPENSEARCH_JAVA_OPTS%
 
-%JAVA% ^
+"%JAVA%" ^
   %OPENSEARCH_JAVA_OPTS% ^
   -Dopensearch.path.home="%OPENSEARCH_HOME%" ^
   -Dopensearch.path.conf="%OPENSEARCH_PATH_CONF%" ^
diff --git a/distribution/src/bin/opensearch-env b/distribution/src/bin/opensearch-env
index 6fe703a73b2de..cd7a0b2b4520b 100644
--- a/distribution/src/bin/opensearch-env
+++ b/distribution/src/bin/opensearch-env
@@ -28,23 +28,25 @@ while [ -h "$SCRIPT" ] ; do
   fi
 done
 
-# determine OpenSearch home; to do this, we strip from the path until we find
-# bin, and then strip bin (there is an assumption here that there is no nested
-# directory under bin also named bin)
-OPENSEARCH_HOME=`dirname "$SCRIPT"`
-
-# now make OPENSEARCH_HOME absolute
-OPENSEARCH_HOME=`cd "$OPENSEARCH_HOME"; pwd`
-
-while [ "`basename "$OPENSEARCH_HOME"`" != "bin" ]; do
+if [[ -z "$OPENSEARCH_HOME" ]]; then
+  # determine OpenSearch home; to do this, we strip from the path until we find
+  # bin, and then strip bin (there is an assumption here that there is no nested
+  # directory under bin also named bin)
+  OPENSEARCH_HOME=`dirname "$SCRIPT"`
+
+  # now make OPENSEARCH_HOME absolute
+  OPENSEARCH_HOME=`cd "$OPENSEARCH_HOME"; pwd`
+
+  while [ "`basename "$OPENSEARCH_HOME"`" != "bin" ]; do
+    OPENSEARCH_HOME=`dirname "$OPENSEARCH_HOME"`
+  done
   OPENSEARCH_HOME=`dirname "$OPENSEARCH_HOME"`
-done
-OPENSEARCH_HOME=`dirname "$OPENSEARCH_HOME"`
+fi
 
 # now set the classpath
 OPENSEARCH_CLASSPATH="$OPENSEARCH_HOME/lib/*"
 
-# now set the path to java: OPENSEARCH_JAVA_HOME -> JAVA_HOME -> bundled JDK
+# now set the path to java: OPENSEARCH_JAVA_HOME -> JAVA_HOME -> bundled JRE -> bundled JDK
 if [ ! -z "$OPENSEARCH_JAVA_HOME" ]; then
   JAVA="$OPENSEARCH_JAVA_HOME/bin/java"
   JAVA_TYPE="OPENSEARCH_JAVA_HOME"
@@ -55,13 +57,18 @@ else
   if [ $OS = "darwin" ]; then
     # macOS bundled Java
     JAVA="$OPENSEARCH_HOME/jdk.app/Contents/Home/bin/java"
+    JAVA_TYPE="bundled jdk"
   elif [ $OS = "freebsd" ]; then
     # using FreeBSD default java from ports if JAVA_HOME is not set
     JAVA="/usr/local/bin/java"
+    JAVA_TYPE="bundled jdk"
+  elif [ -d "$OPENSEARCH_HOME/jre" ]; then
+    JAVA="$OPENSEARCH_HOME/jre/bin/java"
+    JAVA_TYPE="bundled jre"
   else
     JAVA="$OPENSEARCH_HOME/jdk/bin/java"
+    JAVA_TYPE="bundled jdk"
   fi
-  JAVA_TYPE="bundled jdk"
 fi
 
 if [ ! -x "$JAVA" ]; then
diff --git a/distribution/src/bin/opensearch-env-from-file b/distribution/src/bin/opensearch-env-from-file
index 73cd11123bfff..be5b428c268c8 100644
--- a/distribution/src/bin/opensearch-env-from-file
+++ b/distribution/src/bin/opensearch-env-from-file
@@ -47,4 +47,3 @@ for VAR_NAME_FILE in OPENSEARCH_PASSWORD_FILE KEYSTORE_PASSWORD_FILE ; do
     unset "$VAR_NAME_FILE"
   fi
 done
-
diff --git a/distribution/src/bin/opensearch-env.bat b/distribution/src/bin/opensearch-env.bat
index bc8a6ce53a5f5..be9f0411e39f8 100644
--- a/distribution/src/bin/opensearch-env.bat
+++ b/distribution/src/bin/opensearch-env.bat
@@ -3,6 +3,10 @@ set SCRIPT=%0
 rem determine OpenSearch home; to do this, we strip from the path until we
 rem find bin, and then strip bin (there is an assumption here that there is no
 rem nested directory under bin also named bin)
+if not defined OPENSEARCH_HOME goto opensearch_home_start_setup
+goto opensearch_home_done_setup
+
+:opensearch_home_start_setup
 for %%I in (%SCRIPT%) do set OPENSEARCH_HOME=%%~dpI
 
 :opensearch_home_loop
@@ -13,6 +17,7 @@ if not "%DIRNAME%" == "bin" (
 )
 for %%I in ("%OPENSEARCH_HOME%..") do set OPENSEARCH_HOME=%%~dpfI
 
+:opensearch_home_done_setup
 rem now set the classpath
 set OPENSEARCH_CLASSPATH=!OPENSEARCH_HOME!\lib\*
 
@@ -43,14 +48,14 @@ rem comparing to empty string makes this equivalent to bash -v check on env var
 rem and allows to effectively force use of the bundled jdk when launching OpenSearch
 rem by setting OPENSEARCH_JAVA_HOME= and JAVA_HOME= 
 if not "%OPENSEARCH_JAVA_HOME%" == "" (
-  set JAVA="%OPENSEARCH_JAVA_HOME%\bin\java.exe"
+  set "JAVA=%OPENSEARCH_JAVA_HOME%\bin\java.exe"
   set JAVA_TYPE=OPENSEARCH_JAVA_HOME 
 ) else if not "%JAVA_HOME%" == "" (
-  set JAVA="%JAVA_HOME%\bin\java.exe"
+  set "JAVA=%JAVA_HOME%\bin\java.exe"
   set JAVA_TYPE=JAVA_HOME
 ) else (
-  set JAVA="%OPENSEARCH_HOME%\jdk\bin\java.exe"
-  set JAVA_HOME="%OPENSEARCH_HOME%\jdk"
+  set "JAVA=%OPENSEARCH_HOME%\jdk\bin\java.exe"
+  set "JAVA_HOME=%OPENSEARCH_HOME%\jdk"
   set JAVA_TYPE=bundled jdk
 )
 
@@ -73,5 +78,4 @@ if defined JAVA_OPTS (
 )
 
 rem check the Java version
-%JAVA% -cp "%OPENSEARCH_CLASSPATH%" "org.opensearch.tools.java_version_checker.JavaVersionChecker" || exit /b 1
-
+"%JAVA%" -cp "%OPENSEARCH_CLASSPATH%" "org.opensearch.tools.java_version_checker.JavaVersionChecker" || exit /b 1
diff --git a/distribution/src/bin/opensearch-keystore b/distribution/src/bin/opensearch-keystore
index 794d3eb5eba41..9f6cb65feeeeb 100755
--- a/distribution/src/bin/opensearch-keystore
+++ b/distribution/src/bin/opensearch-keystore
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -e -o pipefail
+
 OPENSEARCH_MAIN_CLASS=org.opensearch.common.settings.KeyStoreCli \
   OPENSEARCH_ADDITIONAL_CLASSPATH_DIRECTORIES=lib/tools/keystore-cli \
   "`dirname "$0"`"/opensearch-cli \
diff --git a/distribution/src/bin/opensearch-node b/distribution/src/bin/opensearch-node
index 210037e933b22..b8b231cc43d4a 100755
--- a/distribution/src/bin/opensearch-node
+++ b/distribution/src/bin/opensearch-node
@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -e -o pipefail
 
 OPENSEARCH_MAIN_CLASS=org.opensearch.cluster.coordination.NodeToolCli \
   "`dirname "$0"`"/opensearch-cli \
diff --git a/distribution/src/bin/opensearch-plugin b/distribution/src/bin/opensearch-plugin
index 64d14e611fd04..b58a2695d2ecf 100755
--- a/distribution/src/bin/opensearch-plugin
+++ b/distribution/src/bin/opensearch-plugin
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -e -o pipefail
+
 OPENSEARCH_MAIN_CLASS=org.opensearch.plugins.PluginCli \
   OPENSEARCH_ADDITIONAL_CLASSPATH_DIRECTORIES=lib/tools/plugin-cli \
   "`dirname "$0"`"/opensearch-cli \
diff --git a/distribution/src/bin/opensearch-service.bat b/distribution/src/bin/opensearch-service.bat
index 4dd8356340d10..c1f3f264ec4a0 100644
--- a/distribution/src/bin/opensearch-service.bat
+++ b/distribution/src/bin/opensearch-service.bat
@@ -8,6 +8,10 @@ if /i "%1" == "install" set NOJAVA=
 
 call "%~dp0opensearch-env.bat" %NOJAVA% || exit /b 1
 
+rem opensearch-service-x64.exe is based off of the Apache Commons Daemon procrun service application.
+rem Run "opensearch-service-x64.exe version" for version information.
+rem Run "opensearch-service-x64.exe help" for command options.
+rem See https://commons.apache.org/proper/commons-daemon/procrun.html for more information.
 set EXECUTABLE=%OPENSEARCH_HOME%\bin\opensearch-service-x64.exe
 if "%SERVICE_ID%" == "" set SERVICE_ID=opensearch-service-x64
 set ARCH=64-bit
@@ -20,6 +24,10 @@ exit /B 1
 set OPENSEARCH_VERSION=${project.version}
 
 if "%SERVICE_LOG_DIR%" == "" set SERVICE_LOG_DIR=%OPENSEARCH_HOME%\logs
+rem The logs directory must exist for the service to start.
+if not exist "%SERVICE_LOG_DIR%" (
+	mkdir "%SERVICE_LOG_DIR%"
+)
 
 if "x%1x" == "xx" goto displayUsage
 set SERVICE_CMD=%1
@@ -45,7 +53,8 @@ echo Usage: opensearch-service.bat install^|remove^|start^|stop^|manager [SERVIC
 goto:eof
 
 :doStart
-"%EXECUTABLE%" //OPENSEARCH//%SERVICE_ID% %LOG_OPTS%
+rem //ES == Execute Service
+"%EXECUTABLE%" //ES//%SERVICE_ID% %LOG_OPTS%
 if not errorlevel 1 goto started
 echo Failed starting '%SERVICE_ID%' service
 exit /B 1
@@ -55,6 +64,7 @@ echo The service '%SERVICE_ID%' has been started
 goto:eof
 
 :doStop
+rem //SS == Stop Service
 "%EXECUTABLE%" //SS//%SERVICE_ID% %LOG_OPTS%
 if not errorlevel 1 goto stopped
 echo Failed stopping '%SERVICE_ID%' service
@@ -65,8 +75,11 @@ echo The service '%SERVICE_ID%' has been stopped
 goto:eof
 
 :doManagment
+rem opensearch-service-mgr.exe is based off of the Apache Commons Daemon procrun monitor application.
+rem See https://commons.apache.org/proper/commons-daemon/procrun.html for more information.
 set EXECUTABLE_MGR=%OPENSEARCH_HOME%\bin\opensearch-service-mgr
-"%EXECUTABLE_MGR%" //OPENSEARCH//%SERVICE_ID%
+rem //ES == Edit Service
+"%EXECUTABLE_MGR%" //ES//%SERVICE_ID%
 if not errorlevel 1 goto managed
 echo Failed starting service manager for '%SERVICE_ID%'
 exit /B 1
@@ -77,6 +90,7 @@ goto:eof
 
 :doRemove
 rem Remove the service
+rem //DS == Delete Service
 "%EXECUTABLE%" //DS//%SERVICE_ID% %LOG_OPTS%
 if not errorlevel 1 goto removed
 echo Failed removing '%SERVICE_ID%' service
@@ -107,7 +121,7 @@ if exist "%JAVA_HOME%\bin\server\jvm.dll" (
 
 :foundJVM
 if not defined OPENSEARCH_TMPDIR (
-  for /f "tokens=* usebackq" %%a in (`CALL %JAVA% -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.TempDirectory"`) do set OPENSEARCH_TMPDIR=%%a
+  for /f "tokens=* usebackq" %%a in (`CALL "%JAVA%" -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.TempDirectory"`) do set OPENSEARCH_TMPDIR=%%a
 )
 
 rem The JVM options parser produces the final JVM options to start
@@ -121,7 +135,7 @@ rem   - third, JVM options from OPENSEARCH_JAVA_OPTS are applied
 rem   - fourth, ergonomic JVM options are applied
 
 @setlocal
-for /F "usebackq delims=" %%a in (`CALL %JAVA% -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.JvmOptionsParser" "!OPENSEARCH_PATH_CONF!" ^|^| echo jvm_options_parser_failed`) do set OPENSEARCH_JAVA_OPTS=%%a
+for /F "usebackq delims=" %%a in (`CALL "%JAVA%" -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.JvmOptionsParser" "!OPENSEARCH_PATH_CONF!" ^|^| echo jvm_options_parser_failed`) do set OPENSEARCH_JAVA_OPTS=%%a
 @endlocal & set "MAYBE_JVM_OPTIONS_PARSER_FAILED=%OPENSEARCH_JAVA_OPTS%" & set OPENSEARCH_JAVA_OPTS=%OPENSEARCH_JAVA_OPTS%
 
 if "%MAYBE_JVM_OPTIONS_PARSER_FAILED%" == "jvm_options_parser_failed" (
@@ -207,6 +221,7 @@ if not "%SERVICE_USERNAME%" == "" (
 		set SERVICE_PARAMS=%SERVICE_PARAMS% --ServiceUser "%SERVICE_USERNAME%" --ServicePassword "%SERVICE_PASSWORD%"
 	)
 )
+rem //IS == Install Service
 "%EXECUTABLE%" //IS//%SERVICE_ID% --Startup %OPENSEARCH_START_TYPE% --StopTimeout %OPENSEARCH_STOP_TIMEOUT% --StartClass org.opensearch.bootstrap.OpenSearch --StartMethod main ++StartParams --quiet --StopClass org.opensearch.bootstrap.OpenSearch --StopMethod close --Classpath "%OPENSEARCH_CLASSPATH%" --JvmMs %JVM_MS% --JvmMx %JVM_MX% --JvmSs %JVM_SS% --JvmOptions %OTHER_JAVA_OPTS% ++JvmOptions %OPENSEARCH_PARAMS% %LOG_OPTS% --PidFile "%SERVICE_ID%.pid" --DisplayName "%SERVICE_DISPLAY_NAME%" --Description "%SERVICE_DESCRIPTION%" --Jvm "%JAVA_HOME%%JVM_DLL%" --StartMode jvm --StopMode jvm --StartPath "%OPENSEARCH_HOME%" %SERVICE_PARAMS% ++Environment HOSTNAME="%%COMPUTERNAME%%"
 
 if not errorlevel 1 goto installed
diff --git a/distribution/src/bin/opensearch-shard b/distribution/src/bin/opensearch-shard
index 59511ee68647d..953c792af16e8 100755
--- a/distribution/src/bin/opensearch-shard
+++ b/distribution/src/bin/opensearch-shard
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -e -o pipefail
+
 OPENSEARCH_MAIN_CLASS=org.opensearch.index.shard.ShardToolCli \
   "`dirname "$0"`"/opensearch-cli \
   "$@"
diff --git a/distribution/src/bin/opensearch-upgrade b/distribution/src/bin/opensearch-upgrade
index 4305fae462726..5aae184341b6b 100755
--- a/distribution/src/bin/opensearch-upgrade
+++ b/distribution/src/bin/opensearch-upgrade
@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -e -o pipefail
 
 OPENSEARCH_MAIN_CLASS=org.opensearch.upgrade.UpgradeCli \
   OPENSEARCH_ADDITIONAL_CLASSPATH_DIRECTORIES=lib/tools/upgrade-cli \
diff --git a/distribution/src/bin/opensearch.bat b/distribution/src/bin/opensearch.bat
index 49a12aa5c968d..cce21504c55b7 100644
--- a/distribution/src/bin/opensearch.bat
+++ b/distribution/src/bin/opensearch.bat
@@ -56,6 +56,12 @@ IF ERRORLEVEL 1 (
 	EXIT /B %ERRORLEVEL%
 )
 
+if "%SERVICE_LOG_DIR%" == "" set SERVICE_LOG_DIR=%OPENSEARCH_HOME%\logs
+rem The logs directory must exist for the service to start.
+if not exist "%SERVICE_LOG_DIR%" (
+	mkdir "%SERVICE_LOG_DIR%"
+)
+
 SET KEYSTORE_PASSWORD=
 IF "%checkpassword%"=="Y" (
   CALL "%~dp0opensearch-keystore.bat" has-passwd --silent
@@ -69,7 +75,7 @@ IF "%checkpassword%"=="Y" (
 )
 
 if not defined OPENSEARCH_TMPDIR (
-  for /f "tokens=* usebackq" %%a in (`CALL %JAVA% -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.TempDirectory"`) do set  OPENSEARCH_TMPDIR=%%a
+  for /f "tokens=* usebackq" %%a in (`CALL "%JAVA%" -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.TempDirectory"`) do set  OPENSEARCH_TMPDIR=%%a
 )
 
 rem The JVM options parser produces the final JVM options to start
@@ -82,7 +88,7 @@ rem     jvm.options.d/*.options
 rem   - third, JVM options from OPENSEARCH_JAVA_OPTS are applied
 rem   - fourth, ergonomic JVM options are applied
 @setlocal
-for /F "usebackq delims=" %%a in (`CALL %JAVA% -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.JvmOptionsParser" "!OPENSEARCH_PATH_CONF!" ^|^| echo jvm_options_parser_failed`) do set OPENSEARCH_JAVA_OPTS=%%a
+for /F "usebackq delims=" %%a in (`CALL "%JAVA%" -cp "!OPENSEARCH_CLASSPATH!" "org.opensearch.tools.launchers.JvmOptionsParser" "!OPENSEARCH_PATH_CONF!" ^|^| echo jvm_options_parser_failed`) do set OPENSEARCH_JAVA_OPTS=%%a
 @endlocal & set "MAYBE_JVM_OPTIONS_PARSER_FAILED=%OPENSEARCH_JAVA_OPTS%" & set OPENSEARCH_JAVA_OPTS=%OPENSEARCH_JAVA_OPTS%
 
 if "%MAYBE_JVM_OPTIONS_PARSER_FAILED%" == "jvm_options_parser_failed" (
@@ -97,7 +103,7 @@ SET KEYSTORE_PASSWORD=!KEYSTORE_PASSWORD:^<=^^^<!
 SET KEYSTORE_PASSWORD=!KEYSTORE_PASSWORD:^>=^^^>!
 SET KEYSTORE_PASSWORD=!KEYSTORE_PASSWORD:^\=^^^\!
 
-ECHO.!KEYSTORE_PASSWORD!| %JAVA% %OPENSEARCH_JAVA_OPTS% -Dopensearch ^
+ECHO.!KEYSTORE_PASSWORD!| "%JAVA%" %OPENSEARCH_JAVA_OPTS% -Dopensearch ^
   -Dopensearch.path.home="%OPENSEARCH_HOME%" -Dopensearch.path.conf="%OPENSEARCH_PATH_CONF%" ^
   -Dopensearch.distribution.type="%OPENSEARCH_DISTRIBUTION_TYPE%" ^
   -Dopensearch.bundled_jdk="%OPENSEARCH_BUNDLED_JDK%" ^
diff --git a/distribution/src/config/jvm.options b/distribution/src/config/jvm.options
index a20baf1be0906..952110c6c0289 100644
--- a/distribution/src/config/jvm.options
+++ b/distribution/src/config/jvm.options
@@ -33,19 +33,19 @@
 ################################################################
 
 ## GC configuration
-8-13:-XX:+UseConcMarkSweepGC
-8-13:-XX:CMSInitiatingOccupancyFraction=75
-8-13:-XX:+UseCMSInitiatingOccupancyOnly
+8-10:-XX:+UseConcMarkSweepGC
+8-10:-XX:CMSInitiatingOccupancyFraction=75
+8-10:-XX:+UseCMSInitiatingOccupancyOnly
 
 ## G1GC Configuration
 # NOTE: G1 GC is only supported on JDK version 10 or later
 # to use G1GC, uncomment the next two lines and update the version on the
 # following three lines to your version of the JDK
-# 10-13:-XX:-UseConcMarkSweepGC
-# 10-13:-XX:-UseCMSInitiatingOccupancyOnly
-14-:-XX:+UseG1GC
-14-:-XX:G1ReservePercent=25
-14-:-XX:InitiatingHeapOccupancyPercent=30
+# 10:-XX:-UseConcMarkSweepGC
+# 10:-XX:-UseCMSInitiatingOccupancyOnly
+11-:-XX:+UseG1GC
+11-:-XX:G1ReservePercent=25
+11-:-XX:InitiatingHeapOccupancyPercent=30
 
 ## JVM temporary directory
 -Djava.io.tmpdir=${OPENSEARCH_TMPDIR}
@@ -78,3 +78,10 @@ ${error.file}
 
 # Explicitly allow security manager (https://bugs.openjdk.java.net/browse/JDK-8270380)
 18-:-Djava.security.manager=allow
+
+# JDK 20+ Incubating Vector Module for SIMD optimizations;
+# disabling may reduce performance on vector optimized lucene
+20:--add-modules=jdk.incubator.vector
+
+# HDFS ForkJoinPool.common() support by SecurityManager
+-Djava.util.concurrent.ForkJoinPool.common.threadFactory=org.opensearch.secure_sm.SecuredForkJoinWorkerThreadFactory
diff --git a/distribution/src/config/log4j2.properties b/distribution/src/config/log4j2.properties
index 4820396c79eb7..bb27aaf2e22e6 100644
--- a/distribution/src/config/log4j2.properties
+++ b/distribution/src/config/log4j2.properties
@@ -195,3 +195,40 @@ logger.index_indexing_slowlog.level = trace
 logger.index_indexing_slowlog.appenderRef.index_indexing_slowlog_rolling.ref = index_indexing_slowlog_rolling
 logger.index_indexing_slowlog.appenderRef.index_indexing_slowlog_rolling_old.ref = index_indexing_slowlog_rolling_old
 logger.index_indexing_slowlog.additivity = false
+
+######## Task details log JSON ####################
+appender.task_detailslog_rolling.type = RollingFile
+appender.task_detailslog_rolling.name = task_detailslog_rolling
+appender.task_detailslog_rolling.fileName = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_task_detailslog.json
+appender.task_detailslog_rolling.filePermissions = rw-r-----
+appender.task_detailslog_rolling.layout.type = OpenSearchJsonLayout
+appender.task_detailslog_rolling.layout.type_name = task_detailslog
+appender.task_detailslog_rolling.layout.opensearchmessagefields=taskId,type,action,description,start_time_millis,resource_stats,metadata
+
+appender.task_detailslog_rolling.filePattern = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_task_detailslog-%i.json.gz
+appender.task_detailslog_rolling.policies.type = Policies
+appender.task_detailslog_rolling.policies.size.type = SizeBasedTriggeringPolicy
+appender.task_detailslog_rolling.policies.size.size = 1GB
+appender.task_detailslog_rolling.strategy.type = DefaultRolloverStrategy
+appender.task_detailslog_rolling.strategy.max = 4
+#################################################
+######## Task details log -  old style pattern ####
+appender.task_detailslog_rolling_old.type = RollingFile
+appender.task_detailslog_rolling_old.name = task_detailslog_rolling_old
+appender.task_detailslog_rolling_old.fileName = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_task_detailslog.log
+appender.task_detailslog_rolling_old.filePermissions = rw-r-----
+appender.task_detailslog_rolling_old.layout.type = PatternLayout
+appender.task_detailslog_rolling_old.layout.pattern = [%d{ISO8601}][%-5p][%-25c{1.}] [%node_name]%marker %m%n
+
+appender.task_detailslog_rolling_old.filePattern = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_task_detailslog-%i.log.gz
+appender.task_detailslog_rolling_old.policies.type = Policies
+appender.task_detailslog_rolling_old.policies.size.type = SizeBasedTriggeringPolicy
+appender.task_detailslog_rolling_old.policies.size.size = 1GB
+appender.task_detailslog_rolling_old.strategy.type = DefaultRolloverStrategy
+appender.task_detailslog_rolling_old.strategy.max = 4
+#################################################
+logger.task_detailslog_rolling.name = task.detailslog
+logger.task_detailslog_rolling.level = trace
+logger.task_detailslog_rolling.appenderRef.task_detailslog_rolling.ref = task_detailslog_rolling
+logger.task_detailslog_rolling.appenderRef.task_detailslog_rolling_old.ref = task_detailslog_rolling_old
+logger.task_detailslog_rolling.additivity = false
diff --git a/distribution/src/config/opensearch.yml b/distribution/src/config/opensearch.yml
index 2188fbe600cbf..1d2cfe7eccae6 100644
--- a/distribution/src/config/opensearch.yml
+++ b/distribution/src/config/opensearch.yml
@@ -86,3 +86,38 @@ ${path.logs}
 # Require explicit names when deleting indices:
 #
 #action.destructive_requires_name: true
+#
+# ---------------------------------- Remote Store -----------------------------------
+# Controls whether cluster imposes index creation only with remote store enabled
+# cluster.remote_store.enabled: true
+#
+# Repository to use for segment upload while enforcing remote store for an index
+# node.attr.remote_store.segment.repository: my-repo-1
+#
+# Repository to use for translog upload while enforcing remote store for an index
+# node.attr.remote_store.translog.repository: my-repo-1
+#
+# ---------------------------------- Experimental Features -----------------------------------
+# Gates the visibility of the experimental segment replication features until they are production ready.
+#
+#opensearch.experimental.feature.segment_replication_experimental.enabled: false
+#
+# Gates the functionality of a new parameter to the snapshot restore API
+# that allows for creation of a new index type that searches a snapshot
+# directly in a remote repository without restoring all index data to disk
+# ahead of time.
+#
+#opensearch.experimental.feature.searchable_snapshot.enabled: false
+#
+#
+# Gates the functionality of enabling extensions to work with OpenSearch.
+# This feature enables applications to extend features of OpenSearch outside of
+# the core.
+#
+#opensearch.experimental.feature.extensions.enabled: false
+#
+#
+# Gates the concurrent segment search feature. This feature enables concurrent segment search in a separate
+# index searcher threadpool.
+#
+#opensearch.experimental.feature.concurrent_segment_search.enabled: false
diff --git a/distribution/tools/java-version-checker/build.gradle b/distribution/tools/java-version-checker/build.gradle
index 9480a86ce6fb7..7fd16b910b293 100644
--- a/distribution/tools/java-version-checker/build.gradle
+++ b/distribution/tools/java-version-checker/build.gradle
@@ -11,8 +11,10 @@
 
 apply plugin: 'opensearch.build'
 
-sourceCompatibility = JavaVersion.VERSION_11
-targetCompatibility = JavaVersion.VERSION_11
+java {
+  sourceCompatibility = JavaVersion.VERSION_11
+  targetCompatibility = JavaVersion.VERSION_11
+}
 
 // targetting very old java versions enables a warning by default on newer JDK: disable it.
 compileJava.options.compilerArgs += '-Xlint:-options'
diff --git a/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersion.java b/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersion.java
deleted file mode 100644
index 7873f29fdff69..0000000000000
--- a/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersion.java
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.tools.java_version_checker;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Objects;
-
-public class JavaVersion {
-
-    public static final List<Integer> CURRENT = parse(System.getProperty("java.specification.version"));
-    public static final List<Integer> JAVA_8 = parse("1.8");
-    public static final List<Integer> JAVA_11 = parse("11");
-
-    static List<Integer> parse(final String value) {
-        if (!value.matches("^0*[0-9]+(\\.[0-9]+)*$")) {
-            throw new IllegalArgumentException(value);
-        }
-
-        final List<Integer> version = new ArrayList<Integer>();
-        final String[] components = value.split("\\.");
-        for (final String component : components) {
-            version.add(Integer.valueOf(component));
-        }
-        return version;
-    }
-
-    public static int majorVersion(final List<Integer> javaVersion) {
-        Objects.requireNonNull(javaVersion);
-        if (javaVersion.get(0) > 1) {
-            return javaVersion.get(0);
-        } else {
-            return javaVersion.get(1);
-        }
-    }
-
-    static int compare(final List<Integer> left, final List<Integer> right) {
-        // lexicographically compare two lists, treating missing entries as zeros
-        final int len = Math.max(left.size(), right.size());
-        for (int i = 0; i < len; i++) {
-            final int l = (i < left.size()) ? left.get(i) : 0;
-            final int r = (i < right.size()) ? right.get(i) : 0;
-            if (l < r) {
-                return -1;
-            }
-            if (r < l) {
-                return 1;
-            }
-        }
-        return 0;
-    }
-
-}
diff --git a/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersionChecker.java b/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersionChecker.java
index e8ff5f3e6f3f2..eb5c7cf1592e7 100644
--- a/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersionChecker.java
+++ b/distribution/tools/java-version-checker/src/main/java/org/opensearch/tools/java_version_checker/JavaVersionChecker.java
@@ -32,18 +32,19 @@
 
 package org.opensearch.tools.java_version_checker;
 
+import java.lang.Runtime.Version;
 import java.util.Arrays;
 import java.util.Locale;
 
 /**
- * Simple program that checks if the runtime Java version is at least 1.8.
+ * Simple program that checks if the runtime Java version is at least 11
  */
 final class JavaVersionChecker {
 
     private JavaVersionChecker() {}
 
     /**
-     * The main entry point. The exit code is 0 if the Java version is at least 1.8, otherwise the exit code is 1.
+     * The main entry point. The exit code is 0 if the Java version is at least 11, otherwise the exit code is 1.
      *
      * @param args the args to the program which are rejected if not empty
      */
@@ -52,23 +53,15 @@ public static void main(final String[] args) {
         if (args.length != 0) {
             throw new IllegalArgumentException("expected zero arguments but was " + Arrays.toString(args));
         }
-        if (JavaVersion.compare(JavaVersion.CURRENT, JavaVersion.JAVA_8) < 0) {
+        if (Runtime.version().compareTo(Version.parse("11")) < 0) {
             final String message = String.format(
                 Locale.ROOT,
-                "the minimum required Java version is 8; your Java version from [%s] does not meet this requirement",
+                "OpenSearch requires Java 11; your Java version from [%s] does not meet this requirement",
                 System.getProperty("java.home")
             );
             errPrintln(message);
             exit(1);
         }
-        if (JavaVersion.compare(JavaVersion.CURRENT, JavaVersion.JAVA_11) < 0) {
-            final String message = String.format(
-                Locale.ROOT,
-                "future versions of OpenSearch will require Java 11; your Java version from [%s] does not meet this requirement",
-                System.getProperty("java.home")
-            );
-            errPrintln(message);
-        }
         exit(0);
     }
 
diff --git a/distribution/tools/keystore-cli/build.gradle b/distribution/tools/keystore-cli/build.gradle
index 1e7473f787ca0..5dcddf3ef127e 100644
--- a/distribution/tools/keystore-cli/build.gradle
+++ b/distribution/tools/keystore-cli/build.gradle
@@ -34,6 +34,8 @@ dependencies {
   compileOnly project(":server")
   compileOnly project(":libs:opensearch-cli")
   testImplementation project(":test:framework")
-  testImplementation 'com.google.jimfs:jimfs:1.2'
-  testRuntimeOnly 'com.google.guava:guava:31.1-jre'
+  testImplementation 'com.google.jimfs:jimfs:1.3.0'
+  testRuntimeOnly("com.google.guava:guava:${versions.guava}") {
+    transitive = false
+  }
 }
diff --git a/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/CreateKeyStoreCommand.java b/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/CreateKeyStoreCommand.java
index b96dd46236b87..a62473ebea0f7 100644
--- a/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/CreateKeyStoreCommand.java
+++ b/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/CreateKeyStoreCommand.java
@@ -32,18 +32,19 @@
 
 package org.opensearch.common.settings;
 
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Arrays;
-
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.KeyStoreAwareCommand;
 import org.opensearch.cli.Terminal;
 import org.opensearch.cli.UserException;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+
 /**
  * A sub-command for the keystore cli to create a new keystore.
  */
diff --git a/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/ListKeyStoreCommand.java b/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/ListKeyStoreCommand.java
index 32f03ec3822de..379b61efc5d32 100644
--- a/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/ListKeyStoreCommand.java
+++ b/distribution/tools/keystore-cli/src/main/java/org/opensearch/common/settings/ListKeyStoreCommand.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.common.settings;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
 import joptsimple.OptionSet;
 import org.opensearch.cli.Terminal;
 import org.opensearch.env.Environment;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
 /**
  * A subcommand for the keystore cli to list all settings in the keystore.
  */
diff --git a/distribution/tools/keystore-cli/src/test/java/org/opensearch/bootstrap/BootstrapTests.java b/distribution/tools/keystore-cli/src/test/java/org/opensearch/bootstrap/BootstrapTests.java
index 5b280f210af03..70dc4c58b3643 100644
--- a/distribution/tools/keystore-cli/src/test/java/org/opensearch/bootstrap/BootstrapTests.java
+++ b/distribution/tools/keystore-cli/src/test/java/org/opensearch/bootstrap/BootstrapTests.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.bootstrap;
 
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.common.settings.KeyStoreCommandTestCase;
 import org.opensearch.common.settings.KeyStoreWrapper;
 import org.opensearch.common.settings.SecureSettings;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
diff --git a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/CreateKeyStoreCommandTests.java b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/CreateKeyStoreCommandTests.java
index 7d07208de766e..966d7e48cef29 100644
--- a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/CreateKeyStoreCommandTests.java
+++ b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/CreateKeyStoreCommandTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.common.settings;
 
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Map;
-
 import org.opensearch.cli.Command;
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.UserException;
 import org.opensearch.env.Environment;
 
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+
 import static org.hamcrest.Matchers.containsString;
 
 public class CreateKeyStoreCommandTests extends KeyStoreCommandTestCase {
diff --git a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreCommandTestCase.java b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreCommandTestCase.java
index aa31e07368fc2..cd982cd53cfab 100644
--- a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreCommandTestCase.java
+++ b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreCommandTestCase.java
@@ -32,25 +32,25 @@
 
 package org.opensearch.common.settings;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.nio.file.FileSystem;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.List;
-
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
-import org.opensearch.core.internal.io.IOUtils;
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.cli.CommandTestCase;
 import org.opensearch.common.io.PathUtilsForTesting;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.junit.After;
 import org.junit.Before;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.FileSystem;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Base test case for manipulating the OpenSearch keystore.
  */
diff --git a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreWrapperTests.java b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreWrapperTests.java
index 2688e7637c9ba..ef8a9e54078c4 100644
--- a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreWrapperTests.java
+++ b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/KeyStoreWrapperTests.java
@@ -39,7 +39,8 @@
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.NIOFSDirectory;
 import org.opensearch.common.Randomness;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
diff --git a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/ListKeyStoreCommandTests.java b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/ListKeyStoreCommandTests.java
index 62d27c4010849..42452d5c12beb 100644
--- a/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/ListKeyStoreCommandTests.java
+++ b/distribution/tools/keystore-cli/src/test/java/org/opensearch/common/settings/ListKeyStoreCommandTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.common.settings;
 
-import java.util.Map;
-
 import org.opensearch.cli.Command;
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.UserException;
 import org.opensearch.env.Environment;
 
+import java.util.Map;
+
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
 
diff --git a/distribution/tools/launchers/build.gradle b/distribution/tools/launchers/build.gradle
index 52100296ac7e6..7028757cdc402 100644
--- a/distribution/tools/launchers/build.gradle
+++ b/distribution/tools/launchers/build.gradle
@@ -38,7 +38,9 @@ dependencies {
   testImplementation "org.hamcrest:hamcrest:${versions.hamcrest}"
 }
 
-archivesBaseName = 'opensearch-launchers'
+base {
+  archivesBaseName = 'opensearch-launchers'
+}
 
 tasks.withType(CheckForbiddenApis).configureEach {
   replaceSignatureFiles 'jdk-signatures'
diff --git a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmErgonomics.java b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmErgonomics.java
index 053d892d0ec2f..cd4bea689f776 100644
--- a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmErgonomics.java
+++ b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmErgonomics.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.tools.launchers;
 
-import org.opensearch.tools.java_version_checker.JavaVersion;
-
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -73,19 +71,7 @@ static List<String> choose(final List<String> userDefinedJvmOptions) throws Inte
         final long heapSize = extractHeapSize(finalJvmOptions);
         final long maxDirectMemorySize = extractMaxDirectMemorySize(finalJvmOptions);
 
-        if (System.getProperty("os.name").startsWith("Windows") && JavaVersion.majorVersion(JavaVersion.CURRENT) == 8) {
-            Launchers.errPrintln("Warning: with JDK 8 on Windows, OpenSearch may be unable to derive correct");
-            Launchers.errPrintln("  ergonomic settings due to a JDK issue (JDK-8074459). Please use a newer");
-            Launchers.errPrintln("  version of Java.");
-        }
-
         if (maxDirectMemorySize == 0 && userDefinedJvmOptions.stream().noneMatch(s -> s.startsWith("-XX:MaxDirectMemorySize"))) {
-
-            if (System.getProperty("os.name").startsWith("Windows") && JavaVersion.majorVersion(JavaVersion.CURRENT) == 8) {
-                Launchers.errPrintln("Warning: MaxDirectMemorySize may have been miscalculated due to JDK-8074459.");
-                Launchers.errPrintln("  Please use a newer version of Java or set MaxDirectMemorySize explicitly.");
-            }
-
             ergonomicChoices.add("-XX:MaxDirectMemorySize=" + heapSize / 2);
         }
         return ergonomicChoices;
diff --git a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmOptionsParser.java b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmOptionsParser.java
index 7703efdc56986..533d1f7e782ba 100644
--- a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmOptionsParser.java
+++ b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/JvmOptionsParser.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.tools.launchers;
 
-import org.opensearch.tools.java_version_checker.JavaVersion;
-
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -183,7 +181,7 @@ List<String> readJvmOptionsFiles(final Path config) throws IOException, JvmOptio
                 Reader reader = new InputStreamReader(is, StandardCharsets.UTF_8);
                 BufferedReader br = new BufferedReader(reader)
             ) {
-                parse(JavaVersion.majorVersion(JavaVersion.CURRENT), br, jvmOptions::add, invalidLines::put);
+                parse(Runtime.version().feature(), br, jvmOptions::add, invalidLines::put);
             }
             if (invalidLines.isEmpty() == false) {
                 throw new JvmOptionsFileParserException(jvmOptionsFile, invalidLines);
diff --git a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/SystemJvmOptions.java b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/SystemJvmOptions.java
index 738d57951c4ef..fc613ccdaae68 100644
--- a/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/SystemJvmOptions.java
+++ b/distribution/tools/launchers/src/main/java/org/opensearch/tools/launchers/SystemJvmOptions.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.tools.launchers;
 
-import org.opensearch.tools.java_version_checker.JavaVersion;
-
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -86,7 +84,7 @@ static List<String> systemJvmOptions() {
     }
 
     private static String maybeShowCodeDetailsInExceptionMessages() {
-        if (JavaVersion.majorVersion(JavaVersion.CURRENT) >= 14) {
+        if (Runtime.version().feature() >= 14) {
             return "-XX:+ShowCodeDetailsInExceptionMessages";
         } else {
             return "";
@@ -101,14 +99,10 @@ private static String javaLocaleProviders() {
          *
          *  Due to internationalization enhancements in JDK 9 OpenSearch need to set the provider to COMPAT otherwise time/date
          *  parsing will break in an incompatible way for some date patterns and locales.
-         *  //TODO COMPAT will be deprecated in jdk14 https://bugs.openjdk.java.net/browse/JDK-8232906
+         *  //TODO COMPAT will be deprecated in at some point, see please https://bugs.openjdk.java.net/browse/JDK-8232906
          * See also: documentation in <code>server/org.opensearch.common.time.IsoCalendarDataProvider</code>
          */
-        if (JavaVersion.majorVersion(JavaVersion.CURRENT) == 8) {
-            return "-Djava.locale.providers=SPI,JRE";
-        } else {
-            return "-Djava.locale.providers=SPI,COMPAT";
-        }
+        return "-Djava.locale.providers=SPI,COMPAT";
     }
 
 }
diff --git a/distribution/tools/launchers/src/test/java/org/opensearch/tools/launchers/JvmErgonomicsTests.java b/distribution/tools/launchers/src/test/java/org/opensearch/tools/launchers/JvmErgonomicsTests.java
index ffdf2c2898032..5a8c9841aa0fe 100644
--- a/distribution/tools/launchers/src/test/java/org/opensearch/tools/launchers/JvmErgonomicsTests.java
+++ b/distribution/tools/launchers/src/test/java/org/opensearch/tools/launchers/JvmErgonomicsTests.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.tools.launchers;
 
-import org.opensearch.tools.java_version_checker.JavaVersion;
-
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -69,8 +67,6 @@ public void testExtractValidHeapSizeUsingMaxHeapSize() throws InterruptedExcepti
     }
 
     public void testExtractValidHeapSizeNoOptionPresent() throws InterruptedException, IOException {
-        // Muted for jdk8/Windows, see: https://github.com/elastic/elasticsearch/issues/47384
-        assumeFalse(System.getProperty("os.name").startsWith("Windows") && JavaVersion.majorVersion(JavaVersion.CURRENT) == 8);
         assertThat(JvmErgonomics.extractHeapSize(JvmErgonomics.finalJvmOptions(Collections.emptyList())), greaterThan(0L));
     }
 
@@ -141,8 +137,6 @@ public void testExtractNoSystemProperties() {
     }
 
     public void testMaxDirectMemorySizeChoice() throws InterruptedException, IOException {
-        // Muted for jdk8/Windows, see: https://github.com/elastic/elasticsearch/issues/47384
-        assumeFalse(System.getProperty("os.name").startsWith("Windows") && JavaVersion.majorVersion(JavaVersion.CURRENT) == 8);
         final Map<String, String> heapMaxDirectMemorySize = new HashMap<>();
         heapMaxDirectMemorySize.put("64M", Long.toString((64L << 20) / 2));
         heapMaxDirectMemorySize.put("512M", Long.toString((512L << 20) / 2));
diff --git a/distribution/tools/plugin-cli/build.gradle b/distribution/tools/plugin-cli/build.gradle
index b2e81491da6bd..2db3fef55d02e 100644
--- a/distribution/tools/plugin-cli/build.gradle
+++ b/distribution/tools/plugin-cli/build.gradle
@@ -30,16 +30,22 @@
 
 apply plugin: 'opensearch.build'
 
-archivesBaseName = 'opensearch-plugin-cli'
+base {
+  archivesBaseName = 'opensearch-plugin-cli'
+}
 
 dependencies {
   compileOnly project(":server")
   compileOnly project(":libs:opensearch-cli")
-  api "org.bouncycastle:bcpg-fips:1.0.5.1"
+  api "org.bouncycastle:bcpg-fips:1.0.7.1"
   api "org.bouncycastle:bc-fips:1.0.2.3"
   testImplementation project(":test:framework")
-  testImplementation 'com.google.jimfs:jimfs:1.2'
-  testRuntimeOnly 'com.google.guava:guava:31.1-jre'
+  testImplementation 'com.google.jimfs:jimfs:1.3.0'
+  testRuntimeOnly("com.google.guava:guava:${versions.guava}") {
+    transitive = false
+  }
+
+  implementation "org.apache.commons:commons-compress:${versions.commonscompress}"
 }
 
 tasks.named("dependencyLicenses").configure {
@@ -78,3 +84,25 @@ thirdPartyAudit.ignoreViolations(
   'org.bouncycastle.jcajce.provider.ProvSunTLSKDF$TLSExtendedMasterSecretGenerator',
   'org.bouncycastle.jcajce.provider.ProvSunTLSKDF$TLSExtendedMasterSecretGenerator$2'
 )
+
+thirdPartyAudit.ignoreMissingClasses(
+  'org.brotli.dec.BrotliInputStream',
+  'org.objectweb.asm.AnnotationVisitor',
+  'org.objectweb.asm.Attribute',
+  'org.objectweb.asm.ClassReader',
+  'org.objectweb.asm.ClassVisitor',
+  'org.objectweb.asm.FieldVisitor',
+  'org.objectweb.asm.Label',
+  'org.objectweb.asm.MethodVisitor',
+  'org.objectweb.asm.Type',
+  'org.tukaani.xz.DeltaOptions',
+  'org.tukaani.xz.FilterOptions',
+  'org.tukaani.xz.LZMA2InputStream',
+  'org.tukaani.xz.LZMA2Options',
+  'org.tukaani.xz.LZMAInputStream',
+  'org.tukaani.xz.LZMAOutputStream',
+  'org.tukaani.xz.MemoryLimitException',
+  'org.tukaani.xz.UnsupportedOptionsException',
+  'org.tukaani.xz.XZ',
+  'org.tukaani.xz.XZOutputStream'
+)
diff --git a/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.5.1.jar.sha1 b/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.5.1.jar.sha1
deleted file mode 100644
index 30c30bb4af8e0..0000000000000
--- a/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.5.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-63a454936d930fadb1c7a3206b8e758378dd0a26
\ No newline at end of file
diff --git a/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.7.1.jar.sha1 b/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.7.1.jar.sha1
new file mode 100644
index 0000000000000..44cebc7c92d87
--- /dev/null
+++ b/distribution/tools/plugin-cli/licenses/bcpg-fips-1.0.7.1.jar.sha1
@@ -0,0 +1 @@
+5e1952428655ea822066f86df2e3ecda8fa0ba2b
\ No newline at end of file
diff --git a/distribution/tools/plugin-cli/licenses/commons-compress-1.24.0.jar.sha1 b/distribution/tools/plugin-cli/licenses/commons-compress-1.24.0.jar.sha1
new file mode 100644
index 0000000000000..23999d1bfbde4
--- /dev/null
+++ b/distribution/tools/plugin-cli/licenses/commons-compress-1.24.0.jar.sha1
@@ -0,0 +1 @@
+b4b1b5a3d9573b2970fddab236102c0a4d27d35e
\ No newline at end of file
diff --git a/distribution/tools/plugin-cli/licenses/commons-compress-LICENSE.txt b/distribution/tools/plugin-cli/licenses/commons-compress-LICENSE.txt
new file mode 100644
index 0000000000000..261eeb9e9f8b2
--- /dev/null
+++ b/distribution/tools/plugin-cli/licenses/commons-compress-LICENSE.txt
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/distribution/tools/plugin-cli/licenses/commons-compress-NOTICE.txt b/distribution/tools/plugin-cli/licenses/commons-compress-NOTICE.txt
new file mode 100644
index 0000000000000..3dcbcdd6d36ee
--- /dev/null
+++ b/distribution/tools/plugin-cli/licenses/commons-compress-NOTICE.txt
@@ -0,0 +1,55 @@
+Apache Commons Compress
+Copyright 2002-2023 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (https://www.apache.org/).
+
+---
+
+The files in the package org.apache.commons.compress.archivers.sevenz
+were derived from the LZMA SDK, version 9.20 (C/ and CPP/7zip/),
+which has been placed in the public domain:
+
+"LZMA SDK is placed in the public domain." (http://www.7-zip.org/sdk.html)
+
+---
+
+The test file lbzip2_32767.bz2 has been copied from libbzip2's source
+repository:
+
+This program, "bzip2", the associated library "libbzip2", and all
+documentation, are copyright (C) 1996-2019 Julian R Seward.  All
+rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. The origin of this software must not be misrepresented; you must
+   not claim that you wrote the original software.  If you use this
+   software in a product, an acknowledgment in the product
+   documentation would be appreciated but is not required.
+
+3. Altered source versions must be plainly marked as such, and must
+   not be misrepresented as being the original software.
+
+4. The name of the author may not be used to endorse or promote
+   products derived from this software without specific prior written
+   permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Julian Seward, jseward@acm.org
diff --git a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/InstallPluginCommand.java b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/InstallPluginCommand.java
index 8acf137043a92..c222b82dfa480 100644
--- a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/InstallPluginCommand.java
+++ b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/InstallPluginCommand.java
@@ -34,6 +34,8 @@
 
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
+import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
+import org.apache.commons.compress.archivers.zip.ZipFile;
 import org.apache.lucene.search.spell.LevenshteinDistance;
 import org.apache.lucene.util.CollectionUtil;
 import org.apache.lucene.util.Constants;
@@ -58,7 +60,7 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.hash.MessageDigests;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 
 import java.io.BufferedReader;
@@ -89,6 +91,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
@@ -99,8 +102,6 @@
 import java.util.Set;
 import java.util.TreeSet;
 import java.util.stream.Collectors;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipInputStream;
 
 import static org.opensearch.cli.Terminal.Verbosity.VERBOSE;
 
@@ -374,7 +375,12 @@ private String getOpenSearchUrl(
                 stagingHash
             );
         } else {
-            baseUrl = String.format(Locale.ROOT, "https://artifacts.opensearch.org/releases/plugins/%s/%s", pluginId, version);
+            baseUrl = String.format(
+                Locale.ROOT,
+                "https://artifacts.opensearch.org/releases/plugins/%s/%s",
+                pluginId,
+                Build.CURRENT.getQualifiedVersion()
+            );
         }
         final String platformUrl = String.format(
             Locale.ROOT,
@@ -711,10 +717,12 @@ private Path unzip(Path zip, Path pluginsDir) throws IOException, UserException
         final Path target = stagingDirectory(pluginsDir);
         pathsToDeleteOnShutdown.add(target);
 
-        try (ZipInputStream zipInput = new ZipInputStream(Files.newInputStream(zip))) {
-            ZipEntry entry;
+        try (ZipFile zipFile = new ZipFile(zip, "UTF8", true, false)) {
+            final Enumeration<? extends ZipArchiveEntry> entries = zipFile.getEntries();
+            ZipArchiveEntry entry;
             byte[] buffer = new byte[8192];
-            while ((entry = zipInput.getNextEntry()) != null) {
+            while (entries.hasMoreElements()) {
+                entry = entries.nextElement();
                 if (entry.getName().startsWith("opensearch/")) {
                     throw new UserException(
                         PLUGIN_MALFORMED,
@@ -742,14 +750,11 @@ private Path unzip(Path zip, Path pluginsDir) throws IOException, UserException
                     Files.createDirectories(targetFile.getParent());
                 }
                 if (entry.isDirectory() == false) {
-                    try (OutputStream out = Files.newOutputStream(targetFile)) {
-                        int len;
-                        while ((len = zipInput.read(buffer)) >= 0) {
-                            out.write(buffer, 0, len);
-                        }
+                    // streams will be auto-closed with try-with-resources
+                    try (OutputStream out = Files.newOutputStream(targetFile); InputStream input = zipFile.getInputStream(entry)) {
+                        input.transferTo(out);
                     }
                 }
-                zipInput.closeEntry();
             }
         } catch (UserException e) {
             IOUtils.rm(target);
diff --git a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/PluginCli.java b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/PluginCli.java
index fc93068ce416b..38647170cc610 100644
--- a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/PluginCli.java
+++ b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/PluginCli.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.plugins;
 
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.cli.Command;
 import org.opensearch.cli.LoggingAwareMultiCommand;
 import org.opensearch.cli.Terminal;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.util.Collection;
diff --git a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/RemovePluginCommand.java b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/RemovePluginCommand.java
index fb567e6609ba9..5c3bfbd0d81a8 100644
--- a/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/RemovePluginCommand.java
+++ b/distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/RemovePluginCommand.java
@@ -38,7 +38,7 @@
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.Terminal;
 import org.opensearch.cli.UserException;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 
 import java.io.IOException;
diff --git a/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/InstallPluginCommandTests.java b/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/InstallPluginCommandTests.java
index c1b4568759f4d..4cd3a84aac136 100644
--- a/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/InstallPluginCommandTests.java
+++ b/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/InstallPluginCommandTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.plugins;
 
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
 import org.apache.lucene.tests.util.LuceneTestCase;
@@ -63,10 +64,10 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.hash.MessageDigests;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
@@ -1049,7 +1050,7 @@ public void assertInstallPluginFromUrl(
 
     public void testOfficialPlugin() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1093,7 +1094,7 @@ public void testOfficialPluginStaging() throws Exception {
 
     public void testOfficialPlatformPlugin() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Platforms.PLATFORM_NAME
             + "-"
@@ -1159,7 +1160,7 @@ public void testMavenChecksumWithoutFilename() throws Exception {
 
     public void testOfficialChecksumWithoutFilename() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1184,7 +1185,7 @@ public void testOfficialChecksumWithoutFilename() throws Exception {
 
     public void testOfficialShaMissing() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1229,7 +1230,7 @@ public void testMavenShaMissing() throws Exception {
 
     public void testInvalidShaFileMissingFilename() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1254,7 +1255,7 @@ public void testInvalidShaFileMissingFilename() throws Exception {
 
     public void testInvalidShaFileMismatchFilename() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1279,7 +1280,7 @@ public void testInvalidShaFileMismatchFilename() throws Exception {
 
     public void testInvalidShaFileContainingExtraLine() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1304,7 +1305,7 @@ public void testInvalidShaFileContainingExtraLine() throws Exception {
 
     public void testSha512Mismatch() throws Exception {
         String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/analysis-icu-"
             + Build.CURRENT.getQualifiedVersion()
             + ".zip";
@@ -1349,7 +1350,7 @@ public void testSha1Mismatch() throws Exception {
     public void testPublicKeyIdMismatchToExpectedPublicKeyId() throws Exception {
         final String icu = "analysis-icu";
         final String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/"
             + icu
             + "-"
@@ -1386,7 +1387,7 @@ public void testPublicKeyIdMismatchToExpectedPublicKeyId() throws Exception {
     public void testFailedSignatureVerification() throws Exception {
         final String icu = "analysis-icu";
         final String url = "https://artifacts.opensearch.org/releases/plugins/analysis-icu/"
-            + Version.CURRENT
+            + Build.CURRENT.getQualifiedVersion()
             + "/"
             + icu
             + "-"
diff --git a/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/ListPluginsCommandTests.java b/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/ListPluginsCommandTests.java
index 376e470159731..9162e32937364 100644
--- a/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/ListPluginsCommandTests.java
+++ b/distribution/tools/plugin-cli/src/test/java/org/opensearch/plugins/ListPluginsCommandTests.java
@@ -32,14 +32,6 @@
 
 package org.opensearch.plugins;
 
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.NoSuchFileException;
-import java.nio.file.Path;
-import java.util.Arrays;
-import java.util.Map;
-import java.util.stream.Collectors;
-
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
@@ -52,6 +44,14 @@
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.stream.Collectors;
+
 @LuceneTestCase.SuppressFileSystems("*")
 public class ListPluginsCommandTests extends OpenSearchTestCase {
 
diff --git a/distribution/tools/upgrade-cli/build.gradle b/distribution/tools/upgrade-cli/build.gradle
index 0e1996f3d68fa..c7bf0ff1d2810 100644
--- a/distribution/tools/upgrade-cli/build.gradle
+++ b/distribution/tools/upgrade-cli/build.gradle
@@ -9,17 +9,21 @@
 
 apply plugin: 'opensearch.build'
 
-archivesBaseName = 'opensearch-upgrade-cli'
+base {
+  archivesBaseName = 'opensearch-upgrade-cli'
+}
 
 dependencies {
   compileOnly project(":server")
   compileOnly project(":libs:opensearch-cli")
   implementation "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
-  implementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  implementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
   implementation "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
   testImplementation project(":test:framework")
   testImplementation 'com.google.jimfs:jimfs:1.2'
-  testRuntimeOnly 'com.google.guava:guava:31.1-jre'
+  testRuntimeOnly("com.google.guava:guava:${versions.guava}") {
+    transitive = false
+  }
 }
 
 tasks.named("dependencyLicenses").configure {
diff --git a/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.13.2.jar.sha1 b/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.13.2.jar.sha1
deleted file mode 100644
index ecd3fb49d5b12..0000000000000
--- a/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ec18851f1976d5b810ae1a5fcc32520d2d38f77a
\ No newline at end of file
diff --git a/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.15.2.jar.sha1 b/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/distribution/tools/upgrade-cli/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/distribution/tools/upgrade-cli/licenses/jackson-databind-2.13.2.jar.sha1 b/distribution/tools/upgrade-cli/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/distribution/tools/upgrade-cli/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/distribution/tools/upgrade-cli/licenses/jackson-databind-2.15.2.jar.sha1 b/distribution/tools/upgrade-cli/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/distribution/tools/upgrade-cli/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/DetectEsInstallationTask.java b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/DetectEsInstallationTask.java
index 24f4b79d12528..90067ffd221bf 100644
--- a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/DetectEsInstallationTask.java
+++ b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/DetectEsInstallationTask.java
@@ -9,6 +9,7 @@
 package org.opensearch.upgrade;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import org.opensearch.Version;
 import org.opensearch.cli.Terminal;
 import org.opensearch.common.SuppressForbidden;
diff --git a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportKeystoreTask.java b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportKeystoreTask.java
index c5d578dfad4df..5d35a7fcc0463 100644
--- a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportKeystoreTask.java
+++ b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportKeystoreTask.java
@@ -12,7 +12,7 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.KeyStoreWrapper;
 import org.opensearch.common.settings.KeystoreWrapperUtil;
-import org.opensearch.common.settings.SecureString;
+import org.opensearch.core.common.settings.SecureString;
 
 import java.io.InputStream;
 
diff --git a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportYmlConfigTask.java b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportYmlConfigTask.java
index 80b8db12b6ec5..6e29bd2d04239 100644
--- a/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportYmlConfigTask.java
+++ b/distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/ImportYmlConfigTask.java
@@ -12,9 +12,9 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.OutputStream;
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/DetectEsInstallationTaskTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/DetectEsInstallationTaskTests.java
index 1038e6d4a484f..a1391ba70a8e8 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/DetectEsInstallationTaskTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/DetectEsInstallationTaskTests.java
@@ -8,7 +8,6 @@
 
 package org.opensearch.upgrade;
 
-import org.junit.Before;
 import org.opensearch.cli.MockTerminal;
 import org.opensearch.cli.Terminal;
 import org.opensearch.common.SuppressForbidden;
@@ -17,6 +16,7 @@
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.File;
 import java.nio.file.Path;
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportLog4jPropertiesTaskTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportLog4jPropertiesTaskTests.java
index 7f67e08c66b9e..529253c9ce824 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportLog4jPropertiesTaskTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportLog4jPropertiesTaskTests.java
@@ -10,7 +10,6 @@
 
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
-import org.junit.Before;
 import org.opensearch.cli.MockTerminal;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
@@ -19,6 +18,7 @@
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.File;
 import java.io.IOException;
@@ -67,7 +67,7 @@ public void testImportLog4jPropertiesTask() throws IOException {
         Properties properties = new Properties();
         properties.load(Files.newInputStream(taskInput.getOpenSearchConfig().resolve(ImportLog4jPropertiesTask.LOG4J_PROPERTIES)));
         assertThat(properties, is(notNullValue()));
-        assertThat(properties.entrySet(), hasSize(137));
+        assertThat(properties.entrySet(), hasSize(165));
         assertThat(properties.get("appender.rolling.layout.type"), equalTo("OpenSearchJsonLayout"));
         assertThat(
             properties.get("appender.deprecation_rolling.fileName"),
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportYmlConfigTaskTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportYmlConfigTaskTests.java
index f328cc21685ad..be03470b201a1 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportYmlConfigTaskTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ImportYmlConfigTaskTests.java
@@ -10,7 +10,6 @@
 
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
-import org.junit.Before;
 import org.opensearch.cli.MockTerminal;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
@@ -19,6 +18,7 @@
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/InstallPluginsTaskTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/InstallPluginsTaskTests.java
index 6cb6f0b7cf116..46e189a4765d0 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/InstallPluginsTaskTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/InstallPluginsTaskTests.java
@@ -8,18 +8,19 @@
 
 package org.opensearch.upgrade;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
-import org.junit.Before;
-import org.mockito.Mockito;
 import org.opensearch.cli.MockTerminal;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.mockito.Mockito;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.mockito.Mockito.spy;
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/UpgradeCliTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/UpgradeCliTests.java
index 3db782925a660..837ce6c1e3010 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/UpgradeCliTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/UpgradeCliTests.java
@@ -10,17 +10,17 @@
 
 import com.google.common.jimfs.Configuration;
 import com.google.common.jimfs.Jimfs;
-import org.junit.After;
-import org.junit.Before;
 import org.opensearch.cli.Command;
 import org.opensearch.cli.CommandTestCase;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.settings.KeyStoreWrapper;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
+import org.junit.After;
+import org.junit.Before;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ValidateInputTaskTests.java b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ValidateInputTaskTests.java
index f72e49d5961bf..fde6e5a995761 100644
--- a/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ValidateInputTaskTests.java
+++ b/distribution/tools/upgrade-cli/src/test/java/org/opensearch/upgrade/ValidateInputTaskTests.java
@@ -8,7 +8,6 @@
 
 package org.opensearch.upgrade;
 
-import org.junit.Before;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.cli.MockTerminal;
 import org.opensearch.common.collect.Tuple;
@@ -17,6 +16,7 @@
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.util.Arrays;
 import java.util.Map;
diff --git a/distribution/tools/upgrade-cli/src/test/resources/config/log4j2.properties b/distribution/tools/upgrade-cli/src/test/resources/config/log4j2.properties
index b9ad71121165a..4b92d3fc62376 100644
--- a/distribution/tools/upgrade-cli/src/test/resources/config/log4j2.properties
+++ b/distribution/tools/upgrade-cli/src/test/resources/config/log4j2.properties
@@ -176,3 +176,38 @@ logger.index_indexing_slowlog.level = trace
 logger.index_indexing_slowlog.appenderRef.index_indexing_slowlog_rolling.ref = index_indexing_slowlog_rolling
 logger.index_indexing_slowlog.appenderRef.index_indexing_slowlog_rolling_old.ref = index_indexing_slowlog_rolling_old
 logger.index_indexing_slowlog.additivity = false
+
+######## Task details log JSON ####################
+appender.task_detailslog_rolling.type = RollingFile
+appender.task_detailslog_rolling.name = task_detailslog_rolling
+appender.task_detailslog_rolling.fileName = ${sys:es.logs.base_path}${sys:file.separator}${sys:es.logs.cluster_name}_task_detailslog.json
+appender.task_detailslog_rolling.layout.type = ESJsonLayout
+appender.task_detailslog_rolling.layout.type_name = task_detailslog
+appender.task_detailslog_rolling.layout.esmessagefields=taskId,type,action,description,start_time_millis,resource_stats,metadata
+
+appender.task_detailslog_rolling.filePattern = ${sys:es.logs.base_path}${sys:file.separator}${sys:es.logs.cluster_name}_task_detailslog-%i.json.gz
+appender.task_detailslog_rolling.policies.type = Policies
+appender.task_detailslog_rolling.policies.size.type = SizeBasedTriggeringPolicy
+appender.task_detailslog_rolling.policies.size.size = 1GB
+appender.task_detailslog_rolling.strategy.type = DefaultRolloverStrategy
+appender.task_detailslog_rolling.strategy.max = 4
+#################################################
+######## Task details log -  old style pattern ####
+appender.task_detailslog_rolling_old.type = RollingFile
+appender.task_detailslog_rolling_old.name = task_detailslog_rolling_old
+appender.task_detailslog_rolling_old.fileName = ${sys:es.logs.base_path}${sys:file.separator}${sys:es.logs.cluster_name}_task_detailslog.log
+appender.task_detailslog_rolling_old.layout.type = PatternLayout
+appender.task_detailslog_rolling_old.layout.pattern = [%d{ISO8601}][%-5p][%-25c{1.}] [%node_name]%marker %m%n
+
+appender.task_detailslog_rolling_old.filePattern = ${sys:es.logs.base_path}${sys:file.separator}${sys:es.logs.cluster_name}_task_detailslog-%i.log.gz
+appender.task_detailslog_rolling_old.policies.type = Policies
+appender.task_detailslog_rolling_old.policies.size.type = SizeBasedTriggeringPolicy
+appender.task_detailslog_rolling_old.policies.size.size = 1GB
+appender.task_detailslog_rolling_old.strategy.type = DefaultRolloverStrategy
+appender.task_detailslog_rolling_old.strategy.max = 4
+#################################################
+logger.task_detailslog_rolling.name = task.detailslog
+logger.task_detailslog_rolling.level = trace
+logger.task_detailslog_rolling.appenderRef.task_detailslog_rolling.ref = task_detailslog_rolling
+logger.task_detailslog_rolling.appenderRef.task_detailslog_rolling_old.ref = task_detailslog_rolling_old
+logger.task_detailslog_rolling.additivity = false
diff --git a/doc-tools/build.gradle b/doc-tools/build.gradle
index 98b2149cb59a9..e6ace21420dda 100644
--- a/doc-tools/build.gradle
+++ b/doc-tools/build.gradle
@@ -2,10 +2,11 @@ plugins {
     id 'java'
 }
 
-group 'org.opensearch'
-version '1.0.0-SNAPSHOT'
+base {
+  group 'org.opensearch'
+  version '1.0.0-SNAPSHOT'
+}
 
 repositories {
     mavenCentral()
 }
-
diff --git a/doc-tools/missing-doclet/build.gradle b/doc-tools/missing-doclet/build.gradle
index e16900afce876..114ccc948951a 100644
--- a/doc-tools/missing-doclet/build.gradle
+++ b/doc-tools/missing-doclet/build.gradle
@@ -5,10 +5,6 @@ plugins {
 group 'org.opensearch'
 version '1.0.0-SNAPSHOT'
 
-repositories {
-    mavenCentral()
-}
-
 tasks.withType(JavaCompile) {
   options.compilerArgs += ["--release", targetCompatibility.toString()]
   options.encoding = "UTF-8"
diff --git a/doc-tools/missing-doclet/src/main/java/org/opensearch/missingdoclet/MissingDoclet.java b/doc-tools/missing-doclet/src/main/java/org/opensearch/missingdoclet/MissingDoclet.java
index 021fc04a42e86..e6122e7baf91a 100644
--- a/doc-tools/missing-doclet/src/main/java/org/opensearch/missingdoclet/MissingDoclet.java
+++ b/doc-tools/missing-doclet/src/main/java/org/opensearch/missingdoclet/MissingDoclet.java
@@ -13,6 +13,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -291,6 +292,22 @@ private void checkComment(Element element) {
         if (ignored.contains(element.toString())) {
             return;
         }
+        // Ignore classes annotated with @Generated and all enclosed elements in them.
+        if (isGenerated(element)) {
+            return;
+        }
+        Element enclosing = element.getEnclosingElement();
+        if (enclosing != null && isGenerated(enclosing)) {
+            return;
+        }
+        // If a package contains only generated classes, ignore the package as well.
+        if (element.getKind() == ElementKind.PACKAGE) {
+            List<? extends Element> enclosedElements = element.getEnclosedElements();
+            Optional<?> elm = enclosedElements.stream().findFirst().filter(e -> ((e.getKind() != ElementKind.CLASS) || !isGenerated(e)));
+            if (elm.isEmpty()) {
+                return;
+            }
+        }
         var tree = docTrees.getDocCommentTree(element);
         if (tree == null || tree.getFirstSentence().isEmpty()) {
             // Check for methods that override other stuff and perhaps inherit their Javadocs.
@@ -313,6 +330,17 @@ private void checkComment(Element element) {
         }
     }
 
+    // Ignore classes annotated with @Generated and all enclosed elements in them.
+    private boolean isGenerated(Element element) {
+        return element
+            .getAnnotationMirrors()
+            .stream()
+            .anyMatch(m -> m
+                .getAnnotationType()
+                .toString() /* ClassSymbol.toString() returns class name */
+                .equalsIgnoreCase("javax.annotation.Generated"));
+    }
+
     private boolean hasInheritedJavadocs(Element element) {
         boolean hasOverrides = element.getAnnotationMirrors().stream()
             .anyMatch(ann -> ann.getAnnotationType().toString().equals(Override.class.getName()));
diff --git a/gradle.properties b/gradle.properties
index 53b593923ce26..7c359ed2b652c 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -9,6 +9,8 @@
 # GitHub history for details.
 #
 
+# Enable build caching
+org.gradle.caching=true
 org.gradle.warning.mode=none
 org.gradle.parallel=true
 org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError -Xss2m \
@@ -17,7 +19,10 @@ org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError -Xss2m \
     --add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED \
     --add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED \
     --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
-options.forkOptions.memoryMaximumSize=2g
+options.forkOptions.memoryMaximumSize=3g
+
+# Disable Gradle Enterprise Gradle plugin's test retry
+systemProp.gradle.enterprise.testretry.enabled=false
 
 # Disable duplicate project id detection
 # See https://docs.gradle.org/current/userguide/upgrading_version_6.html#duplicate_project_names_may_cause_publication_to_fail
diff --git a/gradle/code-coverage.gradle b/gradle/code-coverage.gradle
index de041eae7b72d..dfb4ddba24113 100644
--- a/gradle/code-coverage.gradle
+++ b/gradle/code-coverage.gradle
@@ -10,92 +10,41 @@ apply plugin: 'jacoco'
 
 repositories {
   mavenCentral()
+  gradlePluginPortal()
+  // TODO: Find the way to use the repositories from RepositoriesSetupPlugin
+  maven {
+    url = "https://d1nvenhzbhpy0q.cloudfront.net/snapshots/lucene/"
+  }
 }
 
 allprojects {
   plugins.withId('jacoco') {
-    // The default JaCoCo version in Gradle 6.6.1 is 0.8.5, but at least version 0.8.6 officially supports Java 14
-    jacoco.toolVersion = '0.8.7'
+    jacoco.toolVersion = '0.8.10'
   }
 }
 
-def codeCoverageReportTask = tasks.register("codeCoverageReport", JacocoReport) {
-  description = 'Generates aggregate report from all subprojects.'
-  executionData.setFrom fileTree(dir: '.', include: '**/build/jacoco/*.exec')
-  dependsOn subprojects.findAll(s -> s.tasks.findByName('check') != null).check
-}
-
-tasks.register("codeCoverageReportForUnitTest", JacocoReport) {
-  description = 'Generates aggregate report from all subprojects for unit test.'
-  executionData.setFrom fileTree(dir: '.', include: '**/build/jacoco/test.exec')
-}
-
-tasks.register("codeCoverageReportForIntegrationTest", JacocoReport) {
-  description = 'Generates aggregate report from all subprojects for integration test.'
-  // These kinds of tests are integration test, and the tests can be ran by Gradle tasks with the same name
-  def integrationTestExecPathList = ['**/build/jacoco/integTest.exec',
-                                     '**/build/jacoco/internalClusterTest.exec',
-                                     '**/build/jacoco/javaRestTest.exec',
-                                     '**/build/jacoco/yamlRestTest.exec' ]
-  executionData.setFrom fileTree(dir: '.', include: integrationTestExecPathList)
-}
-
 tasks.withType(JacocoReport).configureEach {
   group = JavaBasePlugin.VERIFICATION_GROUP
 
-  // Select projects with corresponding tests in order to run proper tests and select proper classes to generate the report
-  def projectsWithJavaPlugin = subprojects.findAll { it.pluginManager.hasPlugin('java') }
-  def projectsWithUnitTest = projectsWithJavaPlugin.findAll { it.tasks.findByName('test').enabled }
-  def projectsWithIntegTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('integTest')}
-  def projectsWithAsyncIntegTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('asyncIntegTest')}
-  def projectsWithInternalClusterTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('internalClusterTest')}
-  def projectsWithPooledInternalClusterTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('pooledInternalClusterTest')}
-  def projectsWithJavaRestTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('javaRestTest')}
-  def projectsWithYamlRestTest = projectsWithJavaPlugin.findAll {it.tasks.findByName('yamlRestTest')}
-  def projectsWithIntegrationTest = projectsWithIntegTest + projectsWithAsyncIntegTest + projectsWithInternalClusterTest + projectsWithPooledInternalClusterTest + projectsWithJavaRestTest + projectsWithYamlRestTest
-  def projectsWithTest = projectsWithUnitTest + projectsWithIntegrationTest
-
-  def selectedProjects
-  switch (name) {
-    case "codeCoverageReportForUnitTest":
-      dependsOn projectsWithUnitTest.test
-      selectedProjects = projectsWithUnitTest
-      break
-    case "codeCoverageReportForIntegrationTest":
-      dependsOn projectsWithIntegTest.integTest
-      dependsOn projectsWithAsyncIntegTest.asyncIntegTest
-      dependsOn projectsWithInternalClusterTest.internalClusterTest
-      dependsOn projectsWithPooledInternalClusterTest.pooledInternalClusterTest
-      dependsOn projectsWithJavaRestTest.javaRestTest
-      dependsOn projectsWithYamlRestTest.yamlRestTest
-      selectedProjects = projectsWithIntegrationTest
-      break
-    default:
-      dependsOn projectsWithUnitTest.test
-      dependsOn projectsWithIntegTest.integTest
-      dependsOn projectsWithAsyncIntegTest.asyncIntegTest
-      dependsOn projectsWithInternalClusterTest.internalClusterTest
-      dependsOn projectsWithPooledInternalClusterTest.pooledInternalClusterTest
-      dependsOn projectsWithJavaRestTest.javaRestTest
-      dependsOn projectsWithYamlRestTest.yamlRestTest
-      selectedProjects = projectsWithJavaPlugin
-      break
-  }
-  
-  sourceDirectories.setFrom files(selectedProjects.sourceSets.main.allSource.srcDirs)
-  classDirectories.setFrom files(selectedProjects.sourceSets.main.output)
-
   reports {
     // Code coverage report in HTML and CSV formats are on demand, in case they take extra disk space.
-    xml.getRequired().set(System.getProperty('tests.coverage.report.xml', 'true').toBoolean())
-    html.getRequired().set(System.getProperty('tests.coverage.report.html', 'false').toBoolean())
-    csv.getRequired().set(System.getProperty('tests.coverage.report.csv', 'false').toBoolean())
+    xml.required = System.getProperty('tests.coverage.report.xml', 'true').toBoolean()
+    html.required = System.getProperty('tests.coverage.report.html', 'false').toBoolean()
+    csv.required = System.getProperty('tests.coverage.report.csv', 'false').toBoolean()
   }
 }
 
 if (System.getProperty("tests.coverage")) {
+  reporting {
+    reports {
+      testCodeCoverageReport(JacocoCoverageReport) { 
+        testType = TestSuiteType.UNIT_TEST
+      }
+    }
+  }
+
   // Attach code coverage report task to Gradle check task
   project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME).configure {
-    dependsOn codeCoverageReportTask
+    dependsOn tasks.named('testCodeCoverageReport', JacocoReport) 
   }
 }
diff --git a/gradle/formatting.gradle b/gradle/formatting.gradle
index 19adea33b23b3..e0c5fd9d4974e 100644
--- a/gradle/formatting.gradle
+++ b/gradle/formatting.gradle
@@ -66,14 +66,44 @@ allprojects {
           target '**/*.java'
 
           removeUnusedImports()
+          importOrder(
+              'de.thetaphi',
+              'com.carrotsearch',
+              'com.fasterxml',
+              'com.avast',
+              'com.sun',
+              'com.maxmind|com.github|com.networknt|groovy|nebula',
+              'org.antlr',
+              'software.amazon',
+              'com.azure|com.microsoft|com.ibm|com.google|joptsimple|org.apache|org.bouncycastle|org.codehaus|org.opensearch|org.objectweb|org.joda|org.hamcrest|org.openjdk|org.gradle|org.junit',
+              'javax',
+              'java',
+              '',
+              '\\#java|\\#org.opensearch|\\#org.hamcrest|\\#'
+          )
+
           eclipse().configFile rootProject.file('buildSrc/formatterConfig.xml')
           trimTrailingWhitespace()
+          endWithNewline()
 
+          custom 'Refuse wildcard imports', {
+                // Wildcard imports can't be resolved; fail the build
+                if (it =~ /\s+import .*\*;/) {
+                    throw new AssertionError("Do not use wildcard imports.  'spotlessApply' cannot resolve this issue.")
+                }
+          }
+          
           // See DEVELOPER_GUIDE.md for details of when to enable this.
           if (System.getProperty('spotless.paddedcell') != null) {
             paddedCell()
           }
         }
+        format 'misc', {
+            target '*.md', '*.gradle', '**/*.yaml', '**/*.yml', '**/*.svg'   
+
+            trimTrailingWhitespace()
+            endWithNewline()
+        }
       }
 
       precommit.dependsOn 'spotlessJavaCheck'
diff --git a/gradle/missing-javadoc.gradle b/gradle/missing-javadoc.gradle
index df47a3796c825..a9e64a1a93da5 100644
--- a/gradle/missing-javadoc.gradle
+++ b/gradle/missing-javadoc.gradle
@@ -6,7 +6,10 @@
  * compatible open source license.
  */
 
+
 import javax.annotation.Nullable
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.internal.jvm.Jvm
 
 /**
@@ -68,7 +71,7 @@ allprojects {
       classpath = sourceSets.main.compileClasspath
       srcDirSet = sourceSets.main.java
 
-      outputDir = project.javadoc.destinationDir
+      outputDir = file("${project.buildDir}/tmp/missingJavadoc/")
     }
   }
 }
@@ -106,7 +109,6 @@ configure([
   project(":example-plugins:rest-handler"),
   project(":example-plugins:script-expert-scoring"),
   project(":libs:opensearch-cli"),
-  project(":libs:opensearch-core"),
   project(":libs:opensearch-dissect"),
   project(":libs:opensearch-geo"),
   project(":libs:opensearch-grok"),
@@ -146,6 +148,7 @@ configure([
   project(":plugins:discovery-ec2:qa:amazon-ec2"),
   project(":plugins:discovery-gce"),
   project(":plugins:discovery-gce:qa:gce"),
+  project(":plugins:identity-shiro"),
   project(":plugins:ingest-attachment"),
   project(":plugins:mapper-annotated-text"),
   project(":plugins:mapper-murmur3"),
@@ -156,11 +159,11 @@ configure([
   project(":plugins:repository-s3"),
   project(":plugins:store-smb"),
   project(":plugins:transport-nio"),
+  project(":plugins:crypto-kms"),
   project(":qa:die-with-dignity"),
   project(":qa:os"),
   project(":qa:wildfly"),
   project(":rest-api-spec"),
-  project(":server"),
   project(":test:external-modules:test-delayed-aggs"),
   project(":test:fixtures:azure-fixture"),
   project(":test:fixtures:gcs-fixture"),
@@ -175,9 +178,24 @@ configure([
   }
 }
 
+configure([
+  project(":libs:opensearch-common"),
+  project(":libs:opensearch-core"),
+  project(":libs:opensearch-compress"),
+  project(":server")
+]) {
+  project.tasks.withType(MissingJavadocTask) {
+    // TODO: bump to variable missing level after increasing javadoc coverage
+    javadocMissingLevel = "class"
+  }
+}
+
+@CacheableTask
 class MissingJavadocTask extends DefaultTask {
   @InputFiles
   @SkipWhenEmpty
+  @IgnoreEmptyDirectories
+  @PathSensitive(PathSensitivity.RELATIVE)
   SourceDirectorySet srcDirSet;
 
   @OutputDirectory
@@ -217,7 +235,8 @@ class MissingJavadocTask extends DefaultTask {
   @Input
   def executable
 
-  @Input
+  @InputFiles
+  @PathSensitive(PathSensitivity.RELATIVE)
   def taskResources
 
   /** Utility method to recursively collect all tasks with same name like this one that we depend on */
@@ -270,6 +289,10 @@ class MissingJavadocTask extends DefaultTask {
     if (!classpath.isEmpty()) {
       opts << [ '-classpath', classpath.asPath ]
     }
+
+    opts << [ '-tag', 'opensearch.experimental:a:WARNING: This API is experimental and might change in incompatible ways in the next release.' ]
+    opts << [ '-tag', 'opensearch.internal:a:NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.' ]
+
     opts << [ '-doclet', "org.opensearch.missingdoclet.MissingDoclet" ]
     opts << [ '-docletpath', docletpath.asPath ]
     opts << [ '--missing-level', javadocMissingLevel ]
diff --git a/gradle/runtime-jdk-provision.gradle b/gradle/runtime-jdk-provision.gradle
index 2f0c2f74d6803..6bff164633c25 100644
--- a/gradle/runtime-jdk-provision.gradle
+++ b/gradle/runtime-jdk-provision.gradle
@@ -20,7 +20,11 @@ if (BuildParams.getIsRuntimeJavaHomeSet()) {
   configure(allprojects - project(':build-tools')) {
     project.tasks.withType(Test).configureEach { Test test ->
       if (BuildParams.getIsRuntimeJavaHomeSet()) {
-        test.executable = "${BuildParams.runtimeJavaHome}/bin/java"
+        if (OS.current() == OS.WINDOWS) {
+          test.executable = "${BuildParams.runtimeJavaHome}/bin/java.exe"
+        } else {
+          test.executable = "${BuildParams.runtimeJavaHome}/bin/java"
+        }
       }
     }
   }
@@ -28,7 +32,7 @@ if (BuildParams.getIsRuntimeJavaHomeSet()) {
   jdks {
     provisioned_runtime {
       vendor = VersionProperties.bundledJdkVendor
-      version = VersionProperties.getBundledJdk(OS.current().name().toLowerCase())
+      version = VersionProperties.getBundledJdk(OS.current().name().toLowerCase(), Architecture.current().name().toLowerCase())
       platform = OS.current().name().toLowerCase()
       architecture = Architecture.current().name().toLowerCase()
     }
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 7454180f2ae88..7f93135c49b76 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index daf75f8e132cb..f01f0a84a786a 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -11,7 +11,7 @@
 
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionSha256Sum=c9490e938b221daf0094982288e4038deed954a3f12fb54cbf270ddf4e37d879
+distributionSha256Sum=bb09982fdf52718e4c7b25023d10df6d35a5fff969860bdf5a5bd27a3ab27a9e
diff --git a/gradlew b/gradlew
index 4f906e0c811fc..0adc8e1a53214 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,67 +17,99 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -87,9 +119,9 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,88 +130,120 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=`expr $i + 1`
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index ac1b06f93825d..6689b85beecde 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,7 +41,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/libs/build.gradle b/libs/build.gradle
index 92cb2bdb2efc7..39d2737966b6d 100644
--- a/libs/build.gradle
+++ b/libs/build.gradle
@@ -44,11 +44,12 @@ subprojects {
       dependencies.matching { it instanceof ProjectDependency }.all { ProjectDependency dep ->
         Project depProject = dep.dependencyProject
         if (depProject != null
-          && false == depProject.path.equals(':libs:opensearch-core')
+          && (false == depProject.path.equals(':libs:opensearch-core') &&
+              false == depProject.path.equals(':libs:opensearch-common'))
           && depProject.path.startsWith(':libs')) {
           throw new InvalidUserDataException("projects in :libs "
             + "may not depend on other projects libs except "
-            + ":libs:opensearch-core but "
+            + ":libs:opensearch-core or :libs:opensearch-common but "
             + "${project.path} depends on ${depProject.path}")
         }
       }
diff --git a/libs/cli/build.gradle b/libs/cli/build.gradle
index 7f1e9cb8d04b3..a58c4dafac874 100644
--- a/libs/cli/build.gradle
+++ b/libs/cli/build.gradle
@@ -28,12 +28,11 @@
  * under the License.
  */
 apply plugin: 'opensearch.build'
-apply plugin: 'nebula.optional-base'
 apply plugin: 'opensearch.publish'
 
 dependencies {
   api 'net.sf.jopt-simple:jopt-simple:5.0.4'
-  api project(':libs:opensearch-core')
+  api project(':libs:opensearch-common')
 }
 
 test.enabled = false
diff --git a/libs/cli/src/main/java/org/opensearch/cli/ExitCodes.java b/libs/cli/src/main/java/org/opensearch/cli/ExitCodes.java
index c705177b0d7b6..90efc89a08caf 100644
--- a/libs/cli/src/main/java/org/opensearch/cli/ExitCodes.java
+++ b/libs/cli/src/main/java/org/opensearch/cli/ExitCodes.java
@@ -36,20 +36,34 @@
  * POSIX exit codes.
  */
 public class ExitCodes {
+    /** No error */
     public static final int OK = 0;
-    public static final int USAGE = 64; /* command line usage error */
-    public static final int DATA_ERROR = 65; /* data format error */
-    public static final int NO_INPUT = 66; /* cannot open input */
-    public static final int NO_USER = 67; /* addressee unknown */
-    public static final int NO_HOST = 68; /* host name unknown */
-    public static final int UNAVAILABLE = 69; /* service unavailable */
-    public static final int CODE_ERROR = 70; /* internal software error */
-    public static final int CANT_CREATE = 73; /* can't create (user) output file */
-    public static final int IO_ERROR = 74; /* input/output error */
-    public static final int TEMP_FAILURE = 75; /* temp failure; user is invited to retry */
-    public static final int PROTOCOL = 76; /* remote error in protocol */
-    public static final int NOPERM = 77; /* permission denied */
-    public static final int CONFIG = 78; /* configuration error */
+    /** command line usage error */
+    public static final int USAGE = 64;
+    /** data format error */
+    public static final int DATA_ERROR = 65;
+    /** cannot open input */
+    public static final int NO_INPUT = 66;
+    /** addressee unknown */
+    public static final int NO_USER = 67;
+    /** host name unknown */
+    public static final int NO_HOST = 68;
+    /** service unavailable */
+    public static final int UNAVAILABLE = 69;
+    /** internal software error */
+    public static final int CODE_ERROR = 70;
+    /** can't create (user) output file */
+    public static final int CANT_CREATE = 73;
+    /** input/output error */
+    public static final int IO_ERROR = 74;
+    /** temp failure; user is invited to retry */
+    public static final int TEMP_FAILURE = 75;
+    /** remote error in protocol */
+    public static final int PROTOCOL = 76;
+    /** permission denied */
+    public static final int NOPERM = 77;
+    /** configuration error */
+    public static final int CONFIG = 78;
 
     private ExitCodes() { /* no instance, just constants */ }
 }
diff --git a/libs/cli/src/main/java/org/opensearch/cli/MultiCommand.java b/libs/cli/src/main/java/org/opensearch/cli/MultiCommand.java
index 1bdcd6189c757..837a93ea95f83 100644
--- a/libs/cli/src/main/java/org/opensearch/cli/MultiCommand.java
+++ b/libs/cli/src/main/java/org/opensearch/cli/MultiCommand.java
@@ -36,7 +36,7 @@
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 import joptsimple.util.KeyValuePair;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/libs/cli/src/main/java/org/opensearch/cli/Terminal.java b/libs/cli/src/main/java/org/opensearch/cli/Terminal.java
index 657b95fa052ab..be030c18507ad 100644
--- a/libs/cli/src/main/java/org/opensearch/cli/Terminal.java
+++ b/libs/cli/src/main/java/org/opensearch/cli/Terminal.java
@@ -51,6 +51,8 @@
  * which allows {@link #println(Verbosity,String)} calls which act like a logger,
  * only actually printing if the verbosity level of the terminal is above
  * the verbosity of the message.
+ * @see ConsoleTerminal
+ * @see SystemTerminal
 */
 public abstract class Terminal {
 
@@ -65,35 +67,57 @@ private static PrintWriter newErrorWriter() {
         return new PrintWriter(System.err);
     }
 
-    /** Defines the available verbosity levels of messages to be printed. */
+    /** Defines the available verbosity levels of messages to be printed.*/
     public enum Verbosity {
-        SILENT, /* always printed */
-        NORMAL, /* printed when no options are given to cli */
-        VERBOSE /* printed only when cli is passed verbose option */
+        /** always printed */
+        SILENT,
+        /** printed when no options are given to cli */
+        NORMAL,
+        /** printed only when cli is passed verbose option */
+        VERBOSE
     }
 
     /** The current verbosity for the terminal, defaulting to {@link Verbosity#NORMAL}. */
     private Verbosity verbosity = Verbosity.NORMAL;
 
-    /** The newline used when calling println. */
+    /** The newline separator used when calling println. */
     private final String lineSeparator;
 
+    /** Constructs a new terminal with the given line separator.
+     * @param lineSeparator the line separator to use when calling println
+     * */
     protected Terminal(String lineSeparator) {
         this.lineSeparator = lineSeparator;
     }
 
-    /** Sets the verbosity of the terminal. */
+    /** Sets the {@link Terminal#verbosity} of the terminal. (Default is {@link Verbosity#NORMAL})
+     * @param verbosity the {@link Verbosity} level that will be used for printing
+     * */
     public void setVerbosity(Verbosity verbosity) {
         this.verbosity = verbosity;
     }
 
-    /** Reads clear text from the terminal input. See {@link Console#readLine()}. */
+    /** Reads clear text from the terminal input.
+     * @see Console#readLine()
+     * @param prompt message to display to the user
+     * @return the text entered by the user
+     * */
     public abstract String readText(String prompt);
 
-    /** Reads password text from the terminal input. See {@link Console#readPassword()}}. */
+    /** Reads secret text from the terminal input with echoing disabled.
+     * @see Console#readPassword()
+     * @param prompt message to display to the user
+     * @return the secret as a character array
+     * */
     public abstract char[] readSecret(String prompt);
 
-    /** Read password text form terminal input up to a maximum length. */
+    /** Read secret text from terminal input with echoing disabled, up to a maximum length.
+     * @see Console#readPassword()
+     * @param prompt message to display to the user
+     * @param maxLength the maximum length of the secret
+     * @return the secret as a character array
+     * @throws IllegalStateException if the secret exceeds the maximum length
+     * */
     public char[] readSecret(String prompt, int maxLength) {
         char[] result = readSecret(prompt);
         if (result.length > maxLength) {
@@ -103,30 +127,48 @@ public char[] readSecret(String prompt, int maxLength) {
         return result;
     }
 
-    /** Returns a Writer which can be used to write to the terminal directly using standard output. */
+    /** Returns a Writer which can be used to write to the terminal directly using standard output.
+     * @return a writer to {@link Terminal#DEFAULT} output
+     * @see Terminal.ConsoleTerminal
+     * @see Terminal.SystemTerminal
+     * */
     public abstract PrintWriter getWriter();
 
-    /** Returns a Writer which can be used to write to the terminal directly using standard error. */
+    /** Returns a Writer which can be used to write to the terminal directly using standard error.
+     * @return a writer to stderr
+     * */
     public PrintWriter getErrorWriter() {
         return ERROR_WRITER;
     }
 
-    /** Prints a line to the terminal at {@link Verbosity#NORMAL} verbosity level. */
+    /** Prints a line to the terminal at {@link Verbosity#NORMAL} verbosity level, with a {@link Terminal#lineSeparator}
+     * @param msg the message to print
+     * */
     public final void println(String msg) {
         println(Verbosity.NORMAL, msg);
     }
 
-    /** Prints a line to the terminal at {@code verbosity} level. */
+    /** Prints message to the terminal's standard output at {@link Verbosity} level, with a {@link Terminal#lineSeparator}.
+     * @param verbosity the {@link Verbosity} level at which to print
+     * @param msg the message to print
+     * */
     public final void println(Verbosity verbosity, String msg) {
         print(verbosity, msg + lineSeparator);
     }
 
-    /** Prints message to the terminal's standard output at {@code verbosity} level, without a newline. */
+    /** Prints message to the terminal's standard output at {@link Verbosity} level, without adding a {@link Terminal#lineSeparator}.
+     * @param verbosity the {@link Verbosity} level at which to print
+     * @param msg the message to print
+     * */
     public final void print(Verbosity verbosity, String msg) {
         print(verbosity, msg, false);
     }
 
-    /** Prints message to the terminal at {@code verbosity} level, without a newline. */
+    /** Prints message to either standard or error output at {@link Verbosity} level, without adding a {@link Terminal#lineSeparator}.
+     * @param verbosity the {@link Verbosity} level at which to print.
+     * @param msg the message to print
+     * @param isError if true, prints to standard error instead of standard output
+     * */
     private void print(Verbosity verbosity, String msg, boolean isError) {
         if (isPrintable(verbosity)) {
             PrintWriter writer = isError ? getErrorWriter() : getWriter();
@@ -135,29 +177,44 @@ private void print(Verbosity verbosity, String msg, boolean isError) {
         }
     }
 
-    /** Prints a line to the terminal's standard error at {@link Verbosity#NORMAL} verbosity level, without a newline. */
+    /** Prints a line to the terminal's standard error at {@link Verbosity} level, without adding a {@link Terminal#lineSeparator}.
+     * @param verbosity the {@link Verbosity} level at which to print.
+     * @param msg the message to print
+     * */
     public final void errorPrint(Verbosity verbosity, String msg) {
         print(verbosity, msg, true);
     }
 
-    /** Prints a line to the terminal's standard error at {@link Verbosity#NORMAL} verbosity level. */
+    /** Prints a line to the terminal's standard error at {@link Verbosity#NORMAL} verbosity level, with a {@link Terminal#lineSeparator}
+     * @param msg the message to print
+     * */
     public final void errorPrintln(String msg) {
         errorPrintln(Verbosity.NORMAL, msg);
     }
 
-    /** Prints a line to the terminal's standard error at {@code verbosity} level. */
+    /** Prints a line to the terminal's standard error at {@link Verbosity} level, with a {@link Terminal#lineSeparator}.
+     * @param verbosity the {@link Verbosity} level at which to print.
+     * @param msg the message to print
+     * */
     public final void errorPrintln(Verbosity verbosity, String msg) {
         errorPrint(verbosity, msg + lineSeparator);
     }
 
-    /** Checks if is enough {@code verbosity} level to be printed */
+    /** Checks if given {@link Verbosity} level is high enough to be printed at the level defined by {@link Terminal#verbosity}
+     * @param verbosity the {@link Verbosity} level to check
+     * @return true if the {@link Verbosity} level is high enough to be printed
+     * @see Terminal#setVerbosity(Verbosity)
+     * */
     public final boolean isPrintable(Verbosity verbosity) {
         return this.verbosity.ordinal() >= verbosity.ordinal();
     }
 
     /**
-     * Prompt for a yes or no answer from the user. This method will loop until 'y' or 'n'
+     * Prompt for a yes or no answer from the user. This method will loop until 'y', 'n'
      * (or the default empty value) is entered.
+     * @param prompt the prompt to display to the user
+     * @param defaultYes if true, the default answer is 'y', otherwise it is 'n'
+     * @return true if the user answered 'y', false if the user answered 'n' or the defaultYes value if the user entered nothing
      */
     public final boolean promptYesNo(String prompt, boolean defaultYes) {
         String answerPrompt = defaultYes ? " [Y/n]" : " [y/N]";
@@ -181,6 +238,11 @@ public final boolean promptYesNo(String prompt, boolean defaultYes) {
      * character is immediately preceded by a carriage return, we have
      * a Windows-style newline, so we discard the carriage return as well
      * as the newline.
+     * @param reader the reader to read from
+     * @param maxLength the maximum length of the line to read
+     * @return the line read from the reader
+     * @throws RuntimeException if the line read exceeds the maximum length
+     * @throws RuntimeException if an IOException occurs while reading
      */
     public static char[] readLineToCharArray(Reader reader, int maxLength) {
         char[] buf = new char[maxLength + 2];
@@ -215,6 +277,7 @@ public static char[] readLineToCharArray(Reader reader, int maxLength) {
         }
     }
 
+    /** Flushes the terminal's standard output and standard error. */
     public void flush() {
         this.getWriter().flush();
         this.getErrorWriter().flush();
diff --git a/libs/common/build.gradle b/libs/common/build.gradle
new file mode 100644
index 0000000000000..973fe30d09842
--- /dev/null
+++ b/libs/common/build.gradle
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+import org.opensearch.gradle.info.BuildParams
+
+apply plugin: 'opensearch.publish'
+
+base {
+  archivesBaseName = 'opensearch-common'
+}
+
+dependencies {
+  // This dependency is used only by :libs:core for null-checking interop with other tools
+  compileOnly "com.google.code.findbugs:jsr305:3.0.2"
+
+  /*******
+   *  !!!! NO THIRD PARTY DEPENDENCIES !!!!
+   *******/
+
+  testImplementation "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
+  testImplementation "junit:junit:${versions.junit}"
+  testImplementation "org.hamcrest:hamcrest:${versions.hamcrest}"
+
+  testImplementation(project(":test:framework")) {
+    exclude group: 'org.opensearch', module: 'opensearch-common'
+  }
+}
+
+tasks.withType(JavaCompile).configureEach {
+  options.compilerArgs -= '-Xlint:unchecked'
+}
+
+tasks.named('forbiddenApisMain').configure {
+  // :libs:opensearch-common does not depend on server
+  // TODO: Need to decide how we want to handle for forbidden signatures with the changes to server
+  replaceSignatureFiles 'jdk-signatures'
+}
diff --git a/libs/core/src/main/java/org/opensearch/bootstrap/JarHell.java b/libs/common/src/main/java/org/opensearch/bootstrap/JarHell.java
similarity index 96%
rename from libs/core/src/main/java/org/opensearch/bootstrap/JarHell.java
rename to libs/common/src/main/java/org/opensearch/bootstrap/JarHell.java
index 843a6b982d7ff..c4ba778e7db86 100644
--- a/libs/core/src/main/java/org/opensearch/bootstrap/JarHell.java
+++ b/libs/common/src/main/java/org/opensearch/bootstrap/JarHell.java
@@ -36,6 +36,7 @@
 import org.opensearch.common.io.PathUtils;
 
 import java.io.IOException;
+import java.lang.Runtime.Version;
 import java.net.MalformedURLException;
 import java.net.URISyntaxException;
 import java.net.URL;
@@ -70,6 +71,8 @@
  *   <li>Checks any {@code X-Compile-OpenSearch-Version} value in
  *       the jar manifest is compatible with the current ES</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public class JarHell {
 
@@ -250,7 +253,9 @@ private static void checkManifest(Manifest manifest, Path jar) {
     }
 
     public static void checkVersionFormat(String targetVersion) {
-        if (!JavaVersion.isValid(targetVersion)) {
+        try {
+            Version.parse(targetVersion);
+        } catch (final IllegalArgumentException ex) {
             throw new IllegalStateException(
                 String.format(
                     Locale.ROOT,
@@ -267,16 +272,10 @@ public static void checkVersionFormat(String targetVersion) {
      * required by {@code resource} is compatible with the current installation.
      */
     public static void checkJavaVersion(String resource, String targetVersion) {
-        JavaVersion version = JavaVersion.parse(targetVersion);
-        if (JavaVersion.current().compareTo(version) < 0) {
+        Version version = Version.parse(targetVersion);
+        if (Runtime.version().compareTo(version) < 0) {
             throw new IllegalStateException(
-                String.format(
-                    Locale.ROOT,
-                    "%s requires Java %s:, your system: %s",
-                    resource,
-                    targetVersion,
-                    JavaVersion.current().toString()
-                )
+                String.format(Locale.ROOT, "%s requires Java %s:, your system: %s", resource, targetVersion, Runtime.version().toString())
             );
         }
     }
diff --git a/libs/core/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java b/libs/common/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java
similarity index 97%
rename from libs/core/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java
rename to libs/common/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java
index 8cb81639c504f..97b323975db0a 100644
--- a/libs/core/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java
+++ b/libs/common/src/main/java/org/opensearch/bootstrap/JdkJarHellCheck.java
@@ -44,6 +44,11 @@
 import java.util.HashSet;
 import java.util.Set;
 
+/**
+ * CLI tool for checking jar hell
+ *
+ * @opensearch.internal
+ */
 public class JdkJarHellCheck {
 
     private Set<String> detected = new HashSet<>();
diff --git a/libs/common/src/main/java/org/opensearch/bootstrap/package-info.java b/libs/common/src/main/java/org/opensearch/bootstrap/package-info.java
new file mode 100644
index 0000000000000..f522b1bb91444
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/bootstrap/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Contains JarHell Classes */
+package org.opensearch.bootstrap;
diff --git a/libs/core/src/main/java/org/opensearch/common/Booleans.java b/libs/common/src/main/java/org/opensearch/common/Booleans.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/Booleans.java
rename to libs/common/src/main/java/org/opensearch/common/Booleans.java
index 70536a8f4cc46..2ca061820b2eb 100644
--- a/libs/core/src/main/java/org/opensearch/common/Booleans.java
+++ b/libs/common/src/main/java/org/opensearch/common/Booleans.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common;
 
+/**
+ * Extended Boolean functionality
+ *
+ * @opensearch.internal
+ */
 public final class Booleans {
     private Booleans() {
         throw new AssertionError("No instances intended");
diff --git a/libs/core/src/main/java/org/opensearch/common/CharArrays.java b/libs/common/src/main/java/org/opensearch/common/CharArrays.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/CharArrays.java
rename to libs/common/src/main/java/org/opensearch/common/CharArrays.java
index b579581b7044d..5489c067fc887 100644
--- a/libs/core/src/main/java/org/opensearch/common/CharArrays.java
+++ b/libs/common/src/main/java/org/opensearch/common/CharArrays.java
@@ -40,6 +40,8 @@
 
 /**
  * Helper class similar to Arrays to handle conversions for Char arrays
+ *
+ * @opensearch.api
  */
 public final class CharArrays {
 
diff --git a/server/src/main/java/org/opensearch/common/CheckedBiConsumer.java b/libs/common/src/main/java/org/opensearch/common/CheckedBiConsumer.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/CheckedBiConsumer.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedBiConsumer.java
index 1dc133584829e..50c15bb7a95a8 100644
--- a/server/src/main/java/org/opensearch/common/CheckedBiConsumer.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedBiConsumer.java
@@ -36,6 +36,8 @@
 
 /**
  * A {@link BiConsumer}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface CheckedBiConsumer<T, U, E extends Exception> {
diff --git a/server/src/main/java/org/opensearch/common/CheckedBiFunction.java b/libs/common/src/main/java/org/opensearch/common/CheckedBiFunction.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/CheckedBiFunction.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedBiFunction.java
index 057c189e2ce0a..100588eb6d966 100644
--- a/server/src/main/java/org/opensearch/common/CheckedBiFunction.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedBiFunction.java
@@ -34,6 +34,8 @@
 
 /**
  * A {@link java.util.function.BiFunction}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface CheckedBiFunction<T, U, R, E extends Exception> {
diff --git a/libs/core/src/main/java/org/opensearch/common/CheckedConsumer.java b/libs/common/src/main/java/org/opensearch/common/CheckedConsumer.java
similarity index 93%
rename from libs/core/src/main/java/org/opensearch/common/CheckedConsumer.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedConsumer.java
index d52c69ee517f1..07b4973c3a340 100644
--- a/libs/core/src/main/java/org/opensearch/common/CheckedConsumer.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedConsumer.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.common;
 
+import org.opensearch.common.annotation.PublicApi;
+
 import java.util.function.Consumer;
 
 /**
  * A {@link Consumer}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 @FunctionalInterface
 public interface CheckedConsumer<T, E extends Exception> {
     void accept(T t) throws E;
diff --git a/libs/core/src/main/java/org/opensearch/common/CheckedFunction.java b/libs/common/src/main/java/org/opensearch/common/CheckedFunction.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/common/CheckedFunction.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedFunction.java
index 651f68b17a8d8..9c17ad4b4ee3f 100644
--- a/libs/core/src/main/java/org/opensearch/common/CheckedFunction.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedFunction.java
@@ -36,6 +36,8 @@
 
 /**
  * A {@link Function}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.api
  */
 @FunctionalInterface
 public interface CheckedFunction<T, R, E extends Exception> {
diff --git a/libs/core/src/main/java/org/opensearch/common/CheckedRunnable.java b/libs/common/src/main/java/org/opensearch/common/CheckedRunnable.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/common/CheckedRunnable.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedRunnable.java
index ac1b2b82ade8e..cb773ab789180 100644
--- a/libs/core/src/main/java/org/opensearch/common/CheckedRunnable.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedRunnable.java
@@ -34,6 +34,8 @@
 
 /**
  * A {@link Runnable}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.api
  */
 @FunctionalInterface
 public interface CheckedRunnable<E extends Exception> {
diff --git a/server/src/main/java/org/opensearch/common/CheckedSupplier.java b/libs/common/src/main/java/org/opensearch/common/CheckedSupplier.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/CheckedSupplier.java
rename to libs/common/src/main/java/org/opensearch/common/CheckedSupplier.java
index 8ef1b026c7991..3099146901001 100644
--- a/server/src/main/java/org/opensearch/common/CheckedSupplier.java
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedSupplier.java
@@ -36,6 +36,8 @@
 
 /**
  * A {@link Supplier}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface CheckedSupplier<R, E extends Exception> {
diff --git a/libs/common/src/main/java/org/opensearch/common/CheckedTriFunction.java b/libs/common/src/main/java/org/opensearch/common/CheckedTriFunction.java
new file mode 100644
index 0000000000000..7898226b751f7
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/CheckedTriFunction.java
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common;
+
+/**
+ * A {@link TriFunction}-like interface which allows throwing checked exceptions.
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface CheckedTriFunction<S, T, U, R, E extends Exception> {
+    R apply(S s, T t, U u) throws E;
+}
diff --git a/server/src/main/java/org/opensearch/common/Classes.java b/libs/common/src/main/java/org/opensearch/common/Classes.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/Classes.java
rename to libs/common/src/main/java/org/opensearch/common/Classes.java
index 5a59e6f9862a0..1b297639aff6a 100644
--- a/server/src/main/java/org/opensearch/common/Classes.java
+++ b/libs/common/src/main/java/org/opensearch/common/Classes.java
@@ -34,6 +34,11 @@
 
 import java.lang.reflect.Modifier;
 
+/**
+ * Base class utilities
+ *
+ * @opensearch.internal
+ */
 public class Classes {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/Explicit.java b/libs/common/src/main/java/org/opensearch/common/Explicit.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/Explicit.java
rename to libs/common/src/main/java/org/opensearch/common/Explicit.java
index 8607ba49415f5..66e079c461e75 100644
--- a/server/src/main/java/org/opensearch/common/Explicit.java
+++ b/libs/common/src/main/java/org/opensearch/common/Explicit.java
@@ -43,6 +43,7 @@
  * field mapping settings it is preferable to preserve an explicit
  * choice rather than a choice made only made implicitly by defaults.
  *
+ * @opensearch.internal
  */
 public class Explicit<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java b/libs/common/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java
rename to libs/common/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java
index 4c38483329dec..a6c236fe4fa0a 100644
--- a/server/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java
+++ b/libs/common/src/main/java/org/opensearch/common/ExponentiallyWeightedMovingAverage.java
@@ -37,6 +37,8 @@
 /**
  * Implements exponentially weighted moving averages (commonly abbreviated EWMA) for a single value.
  * This class is safe to share between threads.
+ *
+ * @opensearch.internal
  */
 public class ExponentiallyWeightedMovingAverage {
 
diff --git a/libs/core/src/main/java/org/opensearch/common/Glob.java b/libs/common/src/main/java/org/opensearch/common/Glob.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/Glob.java
rename to libs/common/src/main/java/org/opensearch/common/Glob.java
index 650a38b83fbfc..daf045dd49e3a 100644
--- a/libs/core/src/main/java/org/opensearch/common/Glob.java
+++ b/libs/common/src/main/java/org/opensearch/common/Glob.java
@@ -34,6 +34,8 @@
 
 /**
  * Utility class for glob-like matching
+ *
+ * @opensearch.api
  */
 public class Glob {
 
diff --git a/server/src/main/java/org/opensearch/common/LocalTimeOffset.java b/libs/common/src/main/java/org/opensearch/common/LocalTimeOffset.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/LocalTimeOffset.java
rename to libs/common/src/main/java/org/opensearch/common/LocalTimeOffset.java
index 94347c47e56e0..7e89641927ed5 100644
--- a/server/src/main/java/org/opensearch/common/LocalTimeOffset.java
+++ b/libs/common/src/main/java/org/opensearch/common/LocalTimeOffset.java
@@ -61,6 +61,8 @@
  * <p>
  * So there are two methods to convert from local time back to utc,
  * {@link #localToUtc(long, Strategy)} and {@link #localToUtcInThisOffset(long)}.
+ *
+ * @opensearch.internal
  */
 public abstract class LocalTimeOffset {
     /**
@@ -146,6 +148,11 @@ public final long localToUtcInThisOffset(long localMillis) {
      */
     public abstract long localToUtc(long localMillis, Strategy strat);
 
+    /**
+     * Strategy for a local time
+     *
+     * @opensearch.internal
+     */
     public interface Strategy {
         /**
          * Handle a local time that never actually happened because a "gap"
@@ -206,6 +213,8 @@ public String toString() {
 
     /**
      * How to get instances of {@link LocalTimeOffset}.
+     *
+     * @opensearch.internal
      */
     public abstract static class Lookup {
         /**
@@ -234,6 +243,11 @@ public abstract static class Lookup {
         abstract int size();
     }
 
+    /**
+     * No previous local time offset
+     *
+     * @opensearch.internal
+     */
     private static class NoPrevious extends LocalTimeOffset {
         NoPrevious(long millis) {
             super(millis);
@@ -269,6 +283,11 @@ protected String toString(long millis) {
         }
     }
 
+    /**
+     * Transition for a local time offset
+     *
+     * @opensearch.internal
+     */
     public abstract static class Transition extends LocalTimeOffset {
         private final LocalTimeOffset previous;
         private final long startUtcMillis;
@@ -307,6 +326,11 @@ public long startUtcMillis() {
         }
     }
 
+    /**
+     * Gap for a local time offset
+     *
+     * @opensearch.internal
+     */
     public static class Gap extends Transition {
         private final long firstMissingLocalTime;
         private final long firstLocalTimeAfterGap;
@@ -347,6 +371,11 @@ protected String toString(long millis) {
         }
     }
 
+    /**
+     * Overlap for a local time offset
+     *
+     * @opensearch.internal
+     */
     public static class Overlap extends Transition {
         private final long firstOverlappingLocalTime;
         private final long firstNonOverlappingLocalTime;
@@ -403,6 +432,11 @@ protected String toString(long millis) {
         }
     }
 
+    /**
+     * Fixed lookup the local time offset
+     *
+     * @opensearch.internal
+     */
     private static class FixedLookup extends Lookup {
         private final ZoneId zone;
         private final LocalTimeOffset fixed;
@@ -441,6 +475,8 @@ public boolean anyMoveBackToPreviousDay() {
     /**
      * Looks up transitions by checking whether the date is after the start
      * of each transition. Simple so fast for small numbers of transitions.
+     *
+     * @opensearch.internal
      */
     private static class LinkedListLookup extends AbstractManyTransitionsLookup {
         private final LocalTimeOffset lastOffset;
@@ -477,6 +513,8 @@ public boolean anyMoveBackToPreviousDay() {
     /**
      * Builds an array that can be {@link Arrays#binarySearch(long[], long)}ed
      * for the daylight savings time transitions.
+     *
+     * @openearch.internal
      */
     private static class TransitionArrayLookup extends AbstractManyTransitionsLookup {
         private final LocalTimeOffset[] offsets;
@@ -536,6 +574,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Base class for many transitions lookup
+     *
+     * @opensearch.internal
+     */
     private abstract static class AbstractManyTransitionsLookup extends Lookup {
         protected final ZoneId zone;
         protected final long minUtcMillis;
diff --git a/server/src/main/java/org/opensearch/common/MacAddressProvider.java b/libs/common/src/main/java/org/opensearch/common/MacAddressProvider.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/MacAddressProvider.java
rename to libs/common/src/main/java/org/opensearch/common/MacAddressProvider.java
index 244d3032d2315..db51cc64c5d66 100644
--- a/server/src/main/java/org/opensearch/common/MacAddressProvider.java
+++ b/libs/common/src/main/java/org/opensearch/common/MacAddressProvider.java
@@ -36,6 +36,11 @@
 import java.net.SocketException;
 import java.util.Enumeration;
 
+/**
+ * Provider of MAC addressing
+ *
+ * @opensearch.internal
+ */
 public class MacAddressProvider {
 
     private static byte[] getMacAddress() throws SocketException {
diff --git a/libs/core/src/main/java/org/opensearch/common/MemoizedSupplier.java b/libs/common/src/main/java/org/opensearch/common/MemoizedSupplier.java
similarity index 94%
rename from libs/core/src/main/java/org/opensearch/common/MemoizedSupplier.java
rename to libs/common/src/main/java/org/opensearch/common/MemoizedSupplier.java
index 590dae2323abd..0bfdcf6b7a144 100644
--- a/libs/core/src/main/java/org/opensearch/common/MemoizedSupplier.java
+++ b/libs/common/src/main/java/org/opensearch/common/MemoizedSupplier.java
@@ -34,6 +34,11 @@
 
 import java.util.function.Supplier;
 
+/**
+ * A base supplier using memoization optimization technique
+ *
+ * @opensearch.api
+ */
 public class MemoizedSupplier<T> implements Supplier<T> {
     private Supplier<T> supplier;
     private T value;
diff --git a/server/src/main/java/org/opensearch/common/NamedRegistry.java b/libs/common/src/main/java/org/opensearch/common/NamedRegistry.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/NamedRegistry.java
rename to libs/common/src/main/java/org/opensearch/common/NamedRegistry.java
index c48cbfaedd7de..a0e98d9126628 100644
--- a/server/src/main/java/org/opensearch/common/NamedRegistry.java
+++ b/libs/common/src/main/java/org/opensearch/common/NamedRegistry.java
@@ -41,6 +41,8 @@
 
 /**
  * A registry from String to some class implementation. Used to ensure implementations are registered only once.
+ *
+ * @opensearch.internal
  */
 public class NamedRegistry<T> {
     private final Map<String, T> registry = new HashMap<>();
diff --git a/libs/core/src/main/java/org/opensearch/common/Nullable.java b/libs/common/src/main/java/org/opensearch/common/Nullable.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/common/Nullable.java
rename to libs/common/src/main/java/org/opensearch/common/Nullable.java
index 8660f2dbb5995..c663ef863ed48 100644
--- a/libs/core/src/main/java/org/opensearch/common/Nullable.java
+++ b/libs/common/src/main/java/org/opensearch/common/Nullable.java
@@ -34,6 +34,7 @@
 
 import javax.annotation.CheckForNull;
 import javax.annotation.meta.TypeQualifierNickname;
+
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -45,7 +46,7 @@
  * {@code null} is an acceptable value for that parameter.  It should not be
  * used for parameters of primitive types.
  *
- *
+ * @opensearch.api
  */
 @Documented
 @TypeQualifierNickname
diff --git a/libs/common/src/main/java/org/opensearch/common/Numbers.java b/libs/common/src/main/java/org/opensearch/common/Numbers.java
new file mode 100644
index 0000000000000..d5a364a4a934e
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/Numbers.java
@@ -0,0 +1,271 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * A set of utilities for numbers.
+ *
+ * @opensearch.internal
+ */
+public final class Numbers {
+    public static final BigInteger MAX_UNSIGNED_LONG_VALUE = BigInteger.ONE.shiftLeft(64).subtract(BigInteger.ONE);
+    public static final BigInteger MIN_UNSIGNED_LONG_VALUE = BigInteger.ZERO;
+
+    public static final long MIN_UNSIGNED_LONG_VALUE_AS_LONG = MIN_UNSIGNED_LONG_VALUE.longValue();
+    public static final long MAX_UNSIGNED_LONG_VALUE_AS_LONG = MAX_UNSIGNED_LONG_VALUE.longValue();
+
+    private static final BigInteger MAX_LONG_VALUE = BigInteger.valueOf(Long.MAX_VALUE);
+    private static final BigInteger MIN_LONG_VALUE = BigInteger.valueOf(Long.MIN_VALUE);
+
+    private Numbers() {}
+
+    /**
+     * Converts a long to a byte array.
+     *
+     * @param val The long to convert to a byte array
+     * @return The byte array converted
+     */
+    public static byte[] longToBytes(long val) {
+        byte[] arr = new byte[8];
+        arr[0] = (byte) (val >>> 56);
+        arr[1] = (byte) (val >>> 48);
+        arr[2] = (byte) (val >>> 40);
+        arr[3] = (byte) (val >>> 32);
+        arr[4] = (byte) (val >>> 24);
+        arr[5] = (byte) (val >>> 16);
+        arr[6] = (byte) (val >>> 8);
+        arr[7] = (byte) (val);
+        return arr;
+    }
+
+    /** Returns true if value is neither NaN nor infinite. */
+    public static boolean isValidDouble(double value) {
+        if (Double.isNaN(value) || Double.isInfinite(value)) {
+            return false;
+        }
+        return true;
+    }
+
+    /** Return the long that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to a long that stores the exact same
+     *  value. */
+    public static long toLongExact(Number n) {
+        if (n instanceof Byte || n instanceof Short || n instanceof Integer || n instanceof Long) {
+            return n.longValue();
+        } else if (n instanceof Float || n instanceof Double) {
+            double d = n.doubleValue();
+            if (d != Math.round(d)) {
+                throw new IllegalArgumentException(n + " is not an integer value");
+            }
+            return n.longValue();
+        } else if (n instanceof BigDecimal) {
+            return ((BigDecimal) n).toBigIntegerExact().longValueExact();
+        } else if (n instanceof BigInteger) {
+            return ((BigInteger) n).longValueExact();
+        } else {
+            throw new IllegalArgumentException(
+                "Cannot check whether [" + n + "] of class [" + n.getClass().getName() + "] is actually a long"
+            );
+        }
+    }
+
+    /** Return the {@link BigInteger} that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to a {@link BigInteger} that stores the exact same
+     *  value. */
+    public static BigInteger toBigIntegerExact(Number n) {
+        if (n instanceof Byte || n instanceof Short || n instanceof Integer || n instanceof Long) {
+            return BigInteger.valueOf(n.longValue());
+        } else if (n instanceof Float || n instanceof Double) {
+            double d = n.doubleValue();
+            if (d != Math.round(d)) {
+                throw new IllegalArgumentException(n + " is not an integer value");
+            }
+            return BigInteger.valueOf(n.longValue());
+        } else if (n instanceof BigDecimal) {
+            return ((BigDecimal) n).toBigIntegerExact();
+        } else if (n instanceof BigInteger) {
+            return ((BigInteger) n);
+        } else {
+            throw new IllegalArgumentException("Cannot convert [" + n + "] of class [" + n.getClass().getName() + "] to a BigInteger");
+        }
+    }
+
+    /** Return the unsigned long (as {@link BigInteger}) that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to an unsigned long that stores the exact same
+     *  value. */
+    public static BigInteger toUnsignedLongExact(Number value) {
+        final BigInteger v = Numbers.toBigIntegerExact(value);
+
+        if (v.compareTo(MAX_UNSIGNED_LONG_VALUE) > 0 || v.compareTo(MIN_UNSIGNED_LONG_VALUE) < 0) {
+            throw new IllegalArgumentException("Value [" + value + "] is out of range for an unsigned long");
+        }
+
+        return v;
+    }
+
+    // weak bounds on the BigDecimal representation to allow for coercion
+    private static BigDecimal BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE = BigDecimal.valueOf(Long.MAX_VALUE).add(BigDecimal.ONE);
+    private static BigDecimal BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE = BigDecimal.valueOf(Long.MIN_VALUE).subtract(BigDecimal.ONE);
+    private static BigDecimal BIGDECIMAL_GREATER_THAN_USIGNED_LONG_MAX_VALUE = new BigDecimal(MAX_UNSIGNED_LONG_VALUE).add(BigDecimal.ONE);
+    private static BigDecimal BIGDECIMAL_LESS_THAN_USIGNED_LONG_MIN_VALUE = new BigDecimal(MIN_UNSIGNED_LONG_VALUE).subtract(
+        BigDecimal.ONE
+    );
+
+    /** Return the long that {@code stringValue} stores or throws an exception if the
+     *  stored value cannot be converted to a long that stores the exact same
+     *  value and {@code coerce} is false. */
+    public static long toLong(String stringValue, boolean coerce) {
+        try {
+            return Long.parseLong(stringValue);
+        } catch (NumberFormatException e) {
+            // we will try again with BigDecimal
+        }
+
+        final BigInteger bigIntegerValue;
+        try {
+            BigDecimal bigDecimalValue = new BigDecimal(stringValue);
+            if (bigDecimalValue.compareTo(BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE) >= 0
+                || bigDecimalValue.compareTo(BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE) <= 0) {
+                throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
+            }
+            bigIntegerValue = coerce ? bigDecimalValue.toBigInteger() : bigDecimalValue.toBigIntegerExact();
+        } catch (ArithmeticException e) {
+            throw new IllegalArgumentException("Value [" + stringValue + "] has a decimal part");
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("For input string: \"" + stringValue + "\"");
+        }
+
+        if (bigIntegerValue.compareTo(MAX_LONG_VALUE) > 0 || bigIntegerValue.compareTo(MIN_LONG_VALUE) < 0) {
+            throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
+        }
+
+        return bigIntegerValue.longValue();
+    }
+
+    /** Return the long that {@code stringValue} stores or throws an exception if the
+     *  stored value cannot be converted to a long that stores the exact same
+     *  value and {@code coerce} is false. */
+    public static BigInteger toUnsignedLong(String stringValue, boolean coerce) {
+        final BigInteger bigIntegerValue;
+        try {
+            BigDecimal bigDecimalValue = new BigDecimal(stringValue);
+            if (bigDecimalValue.compareTo(BIGDECIMAL_GREATER_THAN_USIGNED_LONG_MAX_VALUE) >= 0
+                || bigDecimalValue.compareTo(BIGDECIMAL_LESS_THAN_USIGNED_LONG_MIN_VALUE) <= 0) {
+                throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for an unsigned long");
+            }
+            bigIntegerValue = coerce ? bigDecimalValue.toBigInteger() : bigDecimalValue.toBigIntegerExact();
+        } catch (ArithmeticException e) {
+            throw new IllegalArgumentException("Value [" + stringValue + "] has a decimal part");
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("For input string: \"" + stringValue + "\"");
+        }
+
+        if (bigIntegerValue.compareTo(MAX_UNSIGNED_LONG_VALUE) > 0 || bigIntegerValue.compareTo(MIN_UNSIGNED_LONG_VALUE) < 0) {
+            throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for an unsigned long");
+        }
+
+        return bigIntegerValue;
+    }
+
+    /** Return the int that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to an int that stores the exact same
+     *  value. */
+    public static int toIntExact(Number n) {
+        return Math.toIntExact(toLongExact(n));
+    }
+
+    /** Return the short that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to a short that stores the exact same
+     *  value. */
+    public static short toShortExact(Number n) {
+        long l = toLongExact(n);
+        if (l != (short) l) {
+            throw new ArithmeticException("short overflow: " + l);
+        }
+        return (short) l;
+    }
+
+    /** Return the byte that {@code n} stores, or throws an exception if the
+     *  stored value cannot be converted to a byte that stores the exact same
+     *  value. */
+    public static byte toByteExact(Number n) {
+        long l = toLongExact(n);
+        if (l != (byte) l) {
+            throw new ArithmeticException("byte overflow: " + l);
+        }
+        return (byte) l;
+    }
+
+    /**
+     * Return a BigInteger equal to the unsigned value of the
+     * argument.
+     */
+    public static BigInteger toUnsignedBigInteger(long i) {
+        if (i >= 0L) return BigInteger.valueOf(i);
+        else {
+            int upper = (int) (i >>> 32);
+            int lower = (int) i;
+
+            // return (upper << 32) + lower
+            return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32).add(BigInteger.valueOf(Integer.toUnsignedLong(lower)));
+        }
+    }
+
+    /**
+     * Convert unsigned long to double value (see please Guava's com.google.common.primitives.UnsignedLong),
+     * this is faster then going through {@link #toUnsignedBigInteger(long)} conversion.
+     */
+    public static double unsignedLongToDouble(long value) {
+        if (value >= 0) {
+            return (double) value;
+        }
+
+        // The top bit is set, which means that the double value is going to come from the top 53 bits.
+        // So we can ignore the bottom 11, except for rounding. We can unsigned-shift right 1, aka
+        // unsigned-divide by 2, and convert that. Then we'll get exactly half of the desired double
+        // value. But in the specific case where the bottom two bits of the original number are 01, we
+        // want to replace that with 1 in the shifted value for correct rounding.
+        return (double) ((value >>> 1) | (value & 1)) * 2.0;
+    }
+
+    /**
+     * Return the strictly greater next power of two for the given value.
+     * For zero and negative numbers, it returns 1.
+     */
+    public static long nextPowerOfTwo(long value) {
+        return 1L << (Long.SIZE - Long.numberOfLeadingZeros(value));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java b/libs/common/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java
similarity index 76%
rename from server/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java
rename to libs/common/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java
index e8b79f33f2313..f83ef930688f8 100644
--- a/server/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java
+++ b/libs/common/src/main/java/org/opensearch/common/RandomBasedUUIDGenerator.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.common;
 
-import org.opensearch.common.settings.SecureString;
-
-import java.util.Arrays;
 import java.util.Base64;
 import java.util.Random;
 
+/**
+ * Random UUID generator.
+ *
+ * @opensearch.internal
+ */
 class RandomBasedUUIDGenerator implements UUIDGenerator {
 
     /**
@@ -49,27 +51,6 @@ public String getBase64UUID() {
         return getBase64UUID(SecureRandomHolder.INSTANCE);
     }
 
-    /**
-     * Returns a Base64 encoded {@link SecureString} of a Version 4.0 compatible UUID
-     * as defined here: http://www.ietf.org/rfc/rfc4122.txt
-     */
-    public SecureString getBase64UUIDSecureString() {
-        byte[] uuidBytes = null;
-        byte[] encodedBytes = null;
-        try {
-            uuidBytes = getUUIDBytes(SecureRandomHolder.INSTANCE);
-            encodedBytes = Base64.getUrlEncoder().withoutPadding().encode(uuidBytes);
-            return new SecureString(CharArrays.utf8BytesToChars(encodedBytes));
-        } finally {
-            if (uuidBytes != null) {
-                Arrays.fill(uuidBytes, (byte) 0);
-            }
-            if (encodedBytes != null) {
-                Arrays.fill(encodedBytes, (byte) 0);
-            }
-        }
-    }
-
     /**
      * Returns a Base64 encoded version of a Version 4.0 compatible UUID
      * randomly initialized by the given {@link java.util.Random} instance
diff --git a/server/src/main/java/org/opensearch/common/SecureRandomHolder.java b/libs/common/src/main/java/org/opensearch/common/SecureRandomHolder.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/SecureRandomHolder.java
rename to libs/common/src/main/java/org/opensearch/common/SecureRandomHolder.java
index 37076f8f4e6e4..14844293b3274 100644
--- a/server/src/main/java/org/opensearch/common/SecureRandomHolder.java
+++ b/libs/common/src/main/java/org/opensearch/common/SecureRandomHolder.java
@@ -34,6 +34,11 @@
 
 import java.security.SecureRandom;
 
+/**
+ * Random holder that is secure.
+ *
+ * @opensearch.internal
+ */
 class SecureRandomHolder {
     // class loading is atomic - this is a lazy & safe singleton to be used by this package
     public static final SecureRandom INSTANCE = new SecureRandom();
diff --git a/libs/common/src/main/java/org/opensearch/common/SetOnce.java b/libs/common/src/main/java/org/opensearch/common/SetOnce.java
new file mode 100644
index 0000000000000..a596b5fcdb61d
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/SetOnce.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.common;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A convenient class which offers a semi-immutable object wrapper implementation which allows one
+ * to set the value of an object exactly once, and retrieve it many times. If {@link #set(Object)}
+ * is called more than once, {@link AlreadySetException} is thrown and the operation will fail.
+ *
+ * This is borrowed from lucene's experimental API. It is not reused to eliminate the dependency
+ * on lucene core for such a simple (standalone) utility class that may change beyond OpenSearch needs.
+ *
+ * @opensearch.api
+ */
+public final class SetOnce<T> implements Cloneable {
+
+    /** Thrown when {@link SetOnce#set(Object)} is called more than once. */
+    public static final class AlreadySetException extends IllegalStateException {
+        public AlreadySetException() {
+            super("The object cannot be set twice!");
+        }
+    }
+
+    /** Holding object and marking that it was already set */
+    private static final class Wrapper<T> {
+        private T object;
+
+        private Wrapper(T object) {
+            this.object = object;
+        }
+    }
+
+    private final AtomicReference<Wrapper<T>> set;
+
+    /**
+     * A default constructor which does not set the internal object, and allows setting it by calling
+     * {@link #set(Object)}.
+     */
+    public SetOnce() {
+        set = new AtomicReference<>();
+    }
+
+    /**
+     * Creates a new instance with the internal object set to the given object. Note that any calls to
+     * {@link #set(Object)} afterwards will result in {@link AlreadySetException}
+     *
+     * @throws AlreadySetException if called more than once
+     * @see #set(Object)
+     */
+    public SetOnce(T obj) {
+        set = new AtomicReference<>(new Wrapper<>(obj));
+    }
+
+    /** Sets the given object. If the object has already been set, an exception is thrown. */
+    public final void set(T obj) {
+        if (!trySet(obj)) {
+            throw new AlreadySetException();
+        }
+    }
+
+    /**
+     * Sets the given object if none was set before.
+     *
+     * @return true if object was set successfully, false otherwise
+     */
+    public final boolean trySet(T obj) {
+        return set.compareAndSet(null, new Wrapper<>(obj));
+    }
+
+    /** Returns the object set by {@link #set(Object)}. */
+    public final T get() {
+        Wrapper<T> wrapper = set.get();
+        return wrapper == null ? null : wrapper.object;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/StopWatch.java b/libs/common/src/main/java/org/opensearch/common/StopWatch.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/StopWatch.java
rename to libs/common/src/main/java/org/opensearch/common/StopWatch.java
index 973277fae65b7..dea1b2b695ace 100644
--- a/server/src/main/java/org/opensearch/common/StopWatch.java
+++ b/libs/common/src/main/java/org/opensearch/common/StopWatch.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.common;
 
-import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.unit.TimeValue;
 
 import java.text.NumberFormat;
@@ -54,7 +53,7 @@
  * This class is normally used to verify performance during proof-of-concepts
  * and in development, rather than as part of production applications.
  *
- *
+ * @opensearch.internal
  */
 public class StopWatch {
 
@@ -155,7 +154,7 @@ public StopWatch stop() throws IllegalStateException {
         return this;
     }
 
-    public Releasable timing(String taskName) {
+    public TimingHandle timing(String taskName) {
         start(taskName);
         return this::stop;
     }
@@ -239,6 +238,8 @@ public String toString() {
 
     /**
      * Inner class to hold data about one task executed within the stop watch.
+     *
+     * @opensearch.internal
      */
     public static class TaskInfo {
 
@@ -266,4 +267,14 @@ public TimeValue getTime() {
         }
     }
 
+    /**
+     * Stops the watch and auto calls close in try-with-resources usage
+     *
+     * @opensearch.internal
+     */
+    public interface TimingHandle extends AutoCloseable {
+        @Override
+        void close();
+    }
+
 }
diff --git a/libs/core/src/main/java/org/opensearch/common/SuppressForbidden.java b/libs/common/src/main/java/org/opensearch/common/SuppressForbidden.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/common/SuppressForbidden.java
rename to libs/common/src/main/java/org/opensearch/common/SuppressForbidden.java
index ed4045dd1ef3c..1f1b28bcf6759 100644
--- a/libs/core/src/main/java/org/opensearch/common/SuppressForbidden.java
+++ b/libs/common/src/main/java/org/opensearch/common/SuppressForbidden.java
@@ -38,6 +38,8 @@
 
 /**
  * Annotation to suppress forbidden-apis errors inside a whole class, a method, or a field.
+ *
+ * @opensearch.api
  */
 @Retention(RetentionPolicy.CLASS)
 @Target({ ElementType.CONSTRUCTOR, ElementType.FIELD, ElementType.METHOD, ElementType.TYPE })
diff --git a/server/src/main/java/org/opensearch/common/SuppressLoggerChecks.java b/libs/common/src/main/java/org/opensearch/common/SuppressLoggerChecks.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/SuppressLoggerChecks.java
rename to libs/common/src/main/java/org/opensearch/common/SuppressLoggerChecks.java
index d93743e03f9db..75d3b63a1841d 100644
--- a/server/src/main/java/org/opensearch/common/SuppressLoggerChecks.java
+++ b/libs/common/src/main/java/org/opensearch/common/SuppressLoggerChecks.java
@@ -39,6 +39,8 @@
 
 /**
  * Annotation to suppress logging usage checks errors inside a whole class or a method.
+ *
+ * @opensearch.internal
  */
 @Retention(RetentionPolicy.CLASS)
 @Target({ ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.TYPE })
diff --git a/server/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java b/libs/common/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java
rename to libs/common/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java
index f76f739787f63..b00a4383b388e 100644
--- a/server/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java
+++ b/libs/common/src/main/java/org/opensearch/common/TimeBasedUUIDGenerator.java
@@ -42,6 +42,8 @@
  * structured.
  * For more information about flake ids, check out
  * https://archive.fo/2015.07.08-082503/http://www.boundary.com/blog/2012/01/flake-a-decentralized-k-ordered-unique-id-generator-in-erlang/
+ *
+ * @opensearch.internal
  */
 
 class TimeBasedUUIDGenerator implements UUIDGenerator {
diff --git a/server/src/main/java/org/opensearch/common/TriConsumer.java b/libs/common/src/main/java/org/opensearch/common/TriConsumer.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/TriConsumer.java
rename to libs/common/src/main/java/org/opensearch/common/TriConsumer.java
index 2a41b73ad5388..f98276b6d007d 100644
--- a/server/src/main/java/org/opensearch/common/TriConsumer.java
+++ b/libs/common/src/main/java/org/opensearch/common/TriConsumer.java
@@ -38,6 +38,8 @@
  * @param <S> the type of the first argument
  * @param <T> the type of the second argument
  * @param <U> the type of the third argument
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface TriConsumer<S, T, U> {
diff --git a/server/src/main/java/org/opensearch/common/TriFunction.java b/libs/common/src/main/java/org/opensearch/common/TriFunction.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/TriFunction.java
rename to libs/common/src/main/java/org/opensearch/common/TriFunction.java
index 2ce82eb49aa37..7b1bbece68680 100644
--- a/server/src/main/java/org/opensearch/common/TriFunction.java
+++ b/libs/common/src/main/java/org/opensearch/common/TriFunction.java
@@ -39,6 +39,8 @@
  * @param <T> the type of the second argument
  * @param <U> the type of the third argument
  * @param <R> the return type
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface TriFunction<S, T, U, R> {
diff --git a/server/src/main/java/org/opensearch/common/UUIDGenerator.java b/libs/common/src/main/java/org/opensearch/common/UUIDGenerator.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/UUIDGenerator.java
rename to libs/common/src/main/java/org/opensearch/common/UUIDGenerator.java
index bf94d8346e842..8705f415216d8 100644
--- a/server/src/main/java/org/opensearch/common/UUIDGenerator.java
+++ b/libs/common/src/main/java/org/opensearch/common/UUIDGenerator.java
@@ -34,6 +34,8 @@
 
 /**
  * Generates opaque unique strings.
+ *
+ * @opensearch.internal
  */
 interface UUIDGenerator {
     String getBase64UUID();
diff --git a/server/src/main/java/org/opensearch/common/UUIDs.java b/libs/common/src/main/java/org/opensearch/common/UUIDs.java
similarity index 77%
rename from server/src/main/java/org/opensearch/common/UUIDs.java
rename to libs/common/src/main/java/org/opensearch/common/UUIDs.java
index 5ddb628c237fa..c2e1357a67029 100644
--- a/server/src/main/java/org/opensearch/common/UUIDs.java
+++ b/libs/common/src/main/java/org/opensearch/common/UUIDs.java
@@ -32,14 +32,17 @@
 
 package org.opensearch.common;
 
-import org.opensearch.common.settings.SecureString;
-
 import java.util.Random;
 
+/**
+ * UUID utility class.
+ *
+ * @opensearch.internal
+ */
 public class UUIDs {
 
     private static final RandomBasedUUIDGenerator RANDOM_UUID_GENERATOR = new RandomBasedUUIDGenerator();
-    private static final UUIDGenerator LEGACY_TIME_UUID_GENERATOR = new LegacyTimeBasedUUIDGenerator();
+
     private static final UUIDGenerator TIME_UUID_GENERATOR = new TimeBasedUUIDGenerator();
 
     /** Generates a time-based UUID (similar to Flake IDs), which is preferred when generating an ID to be indexed into a Lucene index as
@@ -48,11 +51,6 @@ public static String base64UUID() {
         return TIME_UUID_GENERATOR.getBase64UUID();
     }
 
-    /** Legacy implementation of {@link #base64UUID()}, for pre 6.0 indices. */
-    public static String legacyBase64UUID() {
-        return LEGACY_TIME_UUID_GENERATOR.getBase64UUID();
-    }
-
     /** Returns a Base64 encoded version of a Version 4.0 compatible UUID as defined here: http://www.ietf.org/rfc/rfc4122.txt, using the
      *  provided {@code Random} instance */
     public static String randomBase64UUID(Random random) {
@@ -64,10 +62,4 @@ public static String randomBase64UUID(Random random) {
     public static String randomBase64UUID() {
         return RANDOM_UUID_GENERATOR.getBase64UUID();
     }
-
-    /** Returns a Base64 encoded {@link SecureString} of a Version 4.0 compatible UUID as defined here: http://www.ietf.org/rfc/rfc4122.txt,
-     *  using a private {@code SecureRandom} instance */
-    public static SecureString randomBase64UUIDSecureString() {
-        return RANDOM_UUID_GENERATOR.getBase64UUIDSecureString();
-    }
 }
diff --git a/server/src/main/java/org/opensearch/common/ValidationException.java b/libs/common/src/main/java/org/opensearch/common/ValidationException.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/ValidationException.java
rename to libs/common/src/main/java/org/opensearch/common/ValidationException.java
index 979d2be5ae148..09e4344df1b80 100644
--- a/server/src/main/java/org/opensearch/common/ValidationException.java
+++ b/libs/common/src/main/java/org/opensearch/common/ValidationException.java
@@ -37,6 +37,8 @@
 
 /**
  * Encapsulates an accumulation of validation errors
+ *
+ * @opensearch.internal
  */
 public class ValidationException extends IllegalArgumentException {
     private final List<String> validationErrors = new ArrayList<>();
diff --git a/server/src/main/java/org/opensearch/action/ActionFuture.java b/libs/common/src/main/java/org/opensearch/common/action/ActionFuture.java
similarity index 95%
rename from server/src/main/java/org/opensearch/action/ActionFuture.java
rename to libs/common/src/main/java/org/opensearch/common/action/ActionFuture.java
index b1795ecf30b11..827b7dfd51705 100644
--- a/server/src/main/java/org/opensearch/action/ActionFuture.java
+++ b/libs/common/src/main/java/org/opensearch/common/action/ActionFuture.java
@@ -30,8 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.common.action;
 
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.unit.TimeValue;
 
 import java.util.concurrent.Future;
@@ -40,8 +41,9 @@
 /**
  * An extension to {@link Future} allowing for simplified "get" operations.
  *
- *
+ * @opensearch.internal
  */
+@PublicApi(since = "1.0.0")
 public interface ActionFuture<T> extends Future<T> {
 
     /**
diff --git a/libs/common/src/main/java/org/opensearch/common/action/package-info.java b/libs/common/src/main/java/org/opensearch/common/action/package-info.java
new file mode 100644
index 0000000000000..4ed2687c80cc9
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/action/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** foundation action classes used across the code base */
+package org.opensearch.common.action;
diff --git a/libs/common/src/main/java/org/opensearch/common/annotation/DeprecatedApi.java b/libs/common/src/main/java/org/opensearch/common/annotation/DeprecatedApi.java
new file mode 100644
index 0000000000000..964380e1a26ce
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/annotation/DeprecatedApi.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+/**
+ * Marks the public APIs as deprecated and scheduled for removal in one of the upcoming
+ * major releases. The types marked with this annotations could only be other {@link PublicApi}s.
+ *
+ * @opensearch.api
+ */
+@Documented
+@Target({
+    ElementType.TYPE,
+    ElementType.PACKAGE,
+    ElementType.METHOD,
+    ElementType.CONSTRUCTOR,
+    ElementType.PARAMETER,
+    ElementType.FIELD,
+    ElementType.ANNOTATION_TYPE,
+    ElementType.MODULE })
+@PublicApi(since = "2.10.0")
+public @interface DeprecatedApi {
+    /**
+     * Version since this API is deprecated
+     */
+    String since();
+
+    /**
+     * Next major version when this API is scheduled for removal
+     */
+    String forRemoval() default "";
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/annotation/ExperimentalApi.java b/libs/common/src/main/java/org/opensearch/common/annotation/ExperimentalApi.java
new file mode 100644
index 0000000000000..001ffd6eb720a
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/annotation/ExperimentalApi.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+/**
+ * Experimental APIs that may not retain source and binary compatibility within major,
+ * minor or patch releases. The types marked with this annotations could only expose
+ * other {@link PublicApi} or {@link ExperimentalApi} types as public members.
+ *
+ * @opensearch.api
+ */
+@Documented
+@Target({
+    ElementType.TYPE,
+    ElementType.PACKAGE,
+    ElementType.METHOD,
+    ElementType.CONSTRUCTOR,
+    ElementType.PARAMETER,
+    ElementType.FIELD,
+    ElementType.ANNOTATION_TYPE,
+    ElementType.MODULE })
+@PublicApi(since = "2.10.0")
+public @interface ExperimentalApi {
+
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/annotation/InternalApi.java b/libs/common/src/main/java/org/opensearch/common/annotation/InternalApi.java
new file mode 100644
index 0000000000000..ae58c49e58c5e
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/annotation/InternalApi.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+/**
+ * Internal APIs that have no compatibility guarantees and should be not used outside
+ * of OpenSearch core components.
+ *
+ * @opensearch.api
+ */
+@Documented
+@Target({
+    ElementType.TYPE,
+    ElementType.PACKAGE,
+    ElementType.METHOD,
+    ElementType.CONSTRUCTOR,
+    ElementType.PARAMETER,
+    ElementType.FIELD,
+    ElementType.ANNOTATION_TYPE,
+    ElementType.MODULE })
+@PublicApi(since = "2.10.0")
+public @interface InternalApi {
+
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/annotation/PublicApi.java b/libs/common/src/main/java/org/opensearch/common/annotation/PublicApi.java
new file mode 100644
index 0000000000000..33862446d6442
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/annotation/PublicApi.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+
+/**
+ * Stable public APIs that retain source and binary compatibility within a major release.
+ * These interfaces can change from one major release to another major release
+ * (e.g. from 1.0 to 2.0). The types marked with this annotations could only expose
+ * other {@link PublicApi} or {@link ExperimentalApi} types as public members.
+ *
+ * @opensearch.api
+ */
+@Documented
+@Target({
+    ElementType.TYPE,
+    ElementType.PACKAGE,
+    ElementType.METHOD,
+    ElementType.CONSTRUCTOR,
+    ElementType.PARAMETER,
+    ElementType.FIELD,
+    ElementType.ANNOTATION_TYPE,
+    ElementType.MODULE })
+@PublicApi(since = "2.10.0")
+public @interface PublicApi {
+    /**
+     * Version when this API was released
+     */
+    String since();
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/annotation/package-info.java b/libs/common/src/main/java/org/opensearch/common/annotation/package-info.java
new file mode 100644
index 0000000000000..7bb79d7579747
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/annotation/package-info.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The OpenSearch API related annotations
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "2.10.0")
+package org.opensearch.common.annotation;
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/Iterators.java b/libs/common/src/main/java/org/opensearch/common/collect/Iterators.java
new file mode 100644
index 0000000000000..9b64932356c10
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/Iterators.java
@@ -0,0 +1,111 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.collect;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+/**
+ * Iterators utility class.
+ *
+ * @opensearch.internal
+ */
+public class Iterators {
+
+    /**
+     * Concat iterators
+     *
+     * @param iterators the iterators to concat
+     * @param <T> the type of iterator
+     * @return a new {@link ConcatenatedIterator}
+     * @throws NullPointerException if iterators is null
+     */
+    public static <T> Iterator<T> concat(Iterator<? extends T>... iterators) {
+        if (iterators == null) {
+            throw new NullPointerException("iterators");
+        }
+
+        // explicit generic type argument needed for type inference
+        return new ConcatenatedIterator<T>(iterators);
+    }
+
+    /**
+     * Concat iterators
+     *
+     * @opensearch.internal
+     */
+    static class ConcatenatedIterator<T> implements Iterator<T> {
+        private final Iterator<? extends T>[] iterators;
+        private int index = 0;
+
+        ConcatenatedIterator(Iterator<? extends T>... iterators) {
+            if (iterators == null) {
+                throw new NullPointerException("iterators");
+            }
+            for (int i = 0; i < iterators.length; i++) {
+                if (iterators[i] == null) {
+                    throw new NullPointerException("iterators[" + i + "]");
+                }
+            }
+            this.iterators = iterators;
+        }
+
+        /**
+         * Returns {@code true} if the iteration has more elements. (In other words, returns {@code true} if {@link #next} would return an
+         * element rather than throwing an exception.)
+         * @return {@code true} if the iteration has more elements
+         */
+        @Override
+        public boolean hasNext() {
+            boolean hasNext = false;
+            while (index < iterators.length && !(hasNext = iterators[index].hasNext())) {
+                index++;
+            }
+
+            return hasNext;
+        }
+
+        /**
+         * Returns the next element in the iteration.
+         * @return the next element in the iteration
+         * @throws NoSuchElementException if the iteration has no more elements
+         */
+        @Override
+        public T next() {
+            if (!hasNext()) {
+                throw new NoSuchElementException();
+            }
+            return iterators[index].next();
+        }
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/List.java b/libs/common/src/main/java/org/opensearch/common/collect/List.java
new file mode 100644
index 0000000000000..07cfc2c019856
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/List.java
@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.collect;
+
+import java.util.Collection;
+
+/**
+ * Java 9 List
+ *
+ *
+ * @opensearch.internal
+ */
+@Deprecated(forRemoval = true)
+public class List {
+
+    /**
+     * Delegates to the Java9 {@code List.of()} method.
+     *
+     * @param <T> the {@code List}'s element type
+     * @return an empty {@code List}
+     */
+    public static <T> java.util.List<T> of() {
+        return java.util.List.of();
+    }
+
+    /**
+     * Delegates to the Java9 {@code List.of()} method.
+     *
+     * @param <T> the {@code List}'s element type
+     * @param e1  the single element
+     * @return a {@code List} containing the specified element
+     */
+    public static <T> java.util.List<T> of(T e1) {
+        return java.util.List.of(e1);
+    }
+
+    /**
+     * Delegates to the Java9 {@code List.of()} method.
+     *
+     * @param <T> the {@code List}'s element type
+     * @param e1  the single element
+     * @return a {@code List} containing the specified element
+     */
+    public static <T> java.util.List<T> of(T e1, T e2) {
+        return java.util.List.of(e1, e2);
+    }
+
+    /**
+     * Delegates to the Java9 {@code List.of()} method.
+     *
+     * @param entries the elements to be contained in the list
+     * @param <T>     the {@code List}'s element type
+     * @return an unmodifiable list containing the specified elements.
+     */
+    @SafeVarargs
+    @SuppressWarnings("varargs")
+    public static <T> java.util.List<T> of(T... entries) {
+        return java.util.List.of(entries);
+    }
+
+    /**
+     * Delegates to the Java9 {@code List.copyOf()} method.
+     *
+     * @param <T>  the {@code List}'s element type
+     * @param coll a {@code Collection} from which elements are drawn, must be non-null
+     * @return a {@code List} containing the elements of the given {@code Collection}
+     */
+    public static <T> java.util.List<T> copyOf(Collection<? extends T> coll) {
+        return java.util.List.copyOf(coll);
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/Map.java b/libs/common/src/main/java/org/opensearch/common/collect/Map.java
new file mode 100644
index 0000000000000..3913c0fd942a4
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/Map.java
@@ -0,0 +1,201 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.collect;
+
+/**
+ * Java 9 Map
+ *
+ *
+ * @opensearch.internal
+ */
+@Deprecated(forRemoval = true)
+public class Map {
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of() {
+        return java.util.Map.of();
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1) {
+        return java.util.Map.of(k1, v1);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2) {
+        return java.util.Map.of(k1, v1, k2, v2);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(
+        K k1,
+        V v1,
+        K k2,
+        V v2,
+        K k3,
+        V v3,
+        K k4,
+        V v4,
+        K k5,
+        V v5,
+        K k6,
+        V v6,
+        K k7,
+        V v7,
+        K k8,
+        V v8
+    ) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(
+        K k1,
+        V v1,
+        K k2,
+        V v2,
+        K k3,
+        V v3,
+        K k4,
+        V v4,
+        K k5,
+        V v5,
+        K k6,
+        V v6,
+        K k7,
+        V v7,
+        K k8,
+        V v8,
+        K k9,
+        V v9
+    ) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.of()} method.
+     */
+    public static <K, V> java.util.Map<K, V> of(
+        K k1,
+        V v1,
+        K k2,
+        V v2,
+        K k3,
+        V v3,
+        K k4,
+        V v4,
+        K k5,
+        V v5,
+        K k6,
+        V v6,
+        K k7,
+        V v7,
+        K k8,
+        V v8,
+        K k9,
+        V v9,
+        K k10,
+        V v10
+    ) {
+        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9, k10, v10);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.ofEntries()} method.
+     */
+    @SafeVarargs
+    @SuppressWarnings("varargs")
+    public static <K, V> java.util.Map<K, V> ofEntries(java.util.Map.Entry<? extends K, ? extends V>... entries) {
+        return java.util.Map.ofEntries(entries);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Map.entry()} method.
+     */
+    public static <K, V> java.util.Map.Entry<K, V> entry(K k, V v) {
+        return java.util.Map.entry(k, v);
+    }
+
+    /**
+     * Delegates to the Java10 {@code Map.copyOf()} method.
+     */
+    public static <K, V> java.util.Map<K, V> copyOf(java.util.Map<? extends K, ? extends V> map) {
+        return java.util.Map.copyOf(map);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/common/collect/MapBuilder.java b/libs/common/src/main/java/org/opensearch/common/collect/MapBuilder.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/collect/MapBuilder.java
rename to libs/common/src/main/java/org/opensearch/common/collect/MapBuilder.java
index 39e95d46e3a4a..7a28f02ab4b43 100644
--- a/server/src/main/java/org/opensearch/common/collect/MapBuilder.java
+++ b/libs/common/src/main/java/org/opensearch/common/collect/MapBuilder.java
@@ -37,6 +37,11 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Builder for a map.
+ *
+ * @opensearch.internal
+ */
 public class MapBuilder<K, V> {
 
     public static <K, V> MapBuilder<K, V> newMapBuilder() {
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/Set.java b/libs/common/src/main/java/org/opensearch/common/collect/Set.java
new file mode 100644
index 0000000000000..0c3899b2aaacd
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/Set.java
@@ -0,0 +1,102 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.collect;
+
+import java.util.Collection;
+
+/**
+ * Java 9 Set
+ *
+ *
+ * @opensearch.internal
+ */
+@Deprecated(forRemoval = true)
+public class Set {
+
+    /**
+     * Delegates to the Java9 {@code Set.of()} method.
+     *
+     * @param <T> the {@code Set}'s element type
+     * @return an empty {@code Set}
+     */
+    public static <T> java.util.Set<T> of() {
+        return java.util.Set.of();
+    }
+
+    /**
+     * Delegates to the Java9 {@code Set.of()} method.
+     *
+     * @param <T> the {@code Set}'s element type
+     * @param e1  the single element
+     * @return a {@code Set} containing the specified element
+     */
+    public static <T> java.util.Set<T> of(T e1) {
+        return java.util.Set.of(e1);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Set.of()} method.
+     *
+     * @param <T> the {@code Set}'s element type
+     * @param e1 the first element
+     * @param e2 the second element
+     * @return a {@code Set} containing the specified element
+     */
+    public static <T> java.util.Set<T> of(T e1, T e2) {
+        return java.util.Set.of(e1, e2);
+    }
+
+    /**
+     * Delegates to the Java9 {@code Set.of()} method.
+     *
+     * @param entries the elements to be contained in the set
+     * @param <T>     the {@code Set}'s element type
+     * @return an unmodifiable set containing the specified elements.
+     */
+    @SafeVarargs
+    @SuppressWarnings("varargs")
+    public static <T> java.util.Set<T> of(T... entries) {
+        return java.util.Set.of(entries);
+    }
+
+    /**
+     * Delegates to the Java10 {@code Set.copyOf} method.
+     *
+     * @param <T>  the {@code Set}'s element type
+     * @param coll a {@code Collection} from which elements are drawn, must be non-null
+     * @return a {@code Set} containing the elements of the given {@code Collection}
+     */
+    public static <T> java.util.Set<T> copyOf(Collection<? extends T> coll) {
+        return java.util.Set.copyOf(coll);
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/Tuple.java b/libs/common/src/main/java/org/opensearch/common/collect/Tuple.java
new file mode 100644
index 0000000000000..d0b94536b0729
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/Tuple.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.collect;
+
+/**
+ * Java 9 Tuple
+ *
+ * todo: deprecate and remove w/ min jdk upgrade to 11?
+ *
+ * @opensearch.internal
+ */
+public class Tuple<V1, V2> {
+
+    public static <V1, V2> Tuple<V1, V2> tuple(V1 v1, V2 v2) {
+        return new Tuple<>(v1, v2);
+    }
+
+    private final V1 v1;
+    private final V2 v2;
+
+    public Tuple(V1 v1, V2 v2) {
+        this.v1 = v1;
+        this.v2 = v2;
+    }
+
+    public V1 v1() {
+        return v1;
+    }
+
+    public V2 v2() {
+        return v2;
+    }
+
+    /**
+     * Returns {@code true} if the given object is also a tuple and the two tuples
+     * have equal {@link #v1()} and {@link #v2()} values.
+     * <p>
+     * Returns {@code false} otherwise, including for {@code null} values or
+     * objects of different types.
+     * <p>
+     * Note: {@code Tuple} instances are equal if the underlying values are
+     * equal, even if the types are different.
+     *
+     * @param o the object to compare to
+     * @return {@code true} if the given object is also a tuple and the two tuples
+     * have equal {@link #v1()} and {@link #v2()} values.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Tuple<?, ?> tuple = (Tuple<?, ?>) o;
+
+        if (v1 != null ? !v1.equals(tuple.v1) : tuple.v1 != null) return false;
+        if (v2 != null ? !v2.equals(tuple.v2) : tuple.v2 != null) return false;
+
+        return true;
+    }
+
+    /**
+     * Returns the hash code value for this Tuple.
+     * @return the hash code value for this Tuple.
+     */
+    @Override
+    public int hashCode() {
+        int result = v1 != null ? v1.hashCode() : 0;
+        result = 31 * result + (v2 != null ? v2.hashCode() : 0);
+        return result;
+    }
+
+    /**
+     * Returns a string representation of a Tuple
+     * @return {@code "Tuple [v1=value1, v2=value2]"}
+     */
+    @Override
+    public String toString() {
+        return "Tuple [v1=" + v1 + ", v2=" + v2 + "]";
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/collect/package-info.java b/libs/common/src/main/java/org/opensearch/common/collect/package-info.java
new file mode 100644
index 0000000000000..d08cfad1d178b
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/collect/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common collections classes used across opensearch. */
+package org.opensearch.common.collect;
diff --git a/libs/core/src/main/java/org/opensearch/common/concurrent/CompletableContext.java b/libs/common/src/main/java/org/opensearch/common/concurrent/CompletableContext.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/concurrent/CompletableContext.java
rename to libs/common/src/main/java/org/opensearch/common/concurrent/CompletableContext.java
index 8565461cc74bd..f7910af51b599 100644
--- a/libs/core/src/main/java/org/opensearch/common/concurrent/CompletableContext.java
+++ b/libs/common/src/main/java/org/opensearch/common/concurrent/CompletableContext.java
@@ -41,6 +41,8 @@
  * an exceptional result. This allows attaching listeners that only handle {@link Exception}.
  *
  * @param <T> the result type
+ *
+ * @opensearch.api
  */
 public class CompletableContext<T> {
 
diff --git a/libs/common/src/main/java/org/opensearch/common/concurrent/package-info.java b/libs/common/src/main/java/org/opensearch/common/concurrent/package-info.java
new file mode 100644
index 0000000000000..d412fdfa4f5dc
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/concurrent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common concurrency utilities used across opensearch. */
+package org.opensearch.common.concurrent;
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/CryptoHandler.java b/libs/common/src/main/java/org/opensearch/common/crypto/CryptoHandler.java
new file mode 100644
index 0000000000000..9572b5b9054b2
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/CryptoHandler.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.crypto;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.io.InputStreamContainer;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Crypto provider abstractions for encryption and decryption of data. Allows registering multiple providers
+ * for defining different ways of encrypting or decrypting data.
+ *
+ * @param <T> Encryption Metadata / CryptoContext
+ * @param <U> Parsed Encryption Metadata / CryptoContext
+ */
+@ExperimentalApi
+public interface CryptoHandler<T, U> extends Closeable {
+
+    /**
+     * To initialise or create a new crypto metadata to be used in encryption. This is needed to set the context before
+     * beginning encryption.
+     *
+     * @return crypto metadata instance
+     */
+    T initEncryptionMetadata();
+
+    /**
+     * To load crypto metadata to be used in encryption from content header.
+     * Note that underlying information in the loaded metadata object is same as present in the object created during
+     * encryption but object type may differ.
+     *
+     * @param encryptedHeaderContentSupplier supplier for encrypted header content.
+     * @return crypto metadata instance used in decryption.
+     */
+    U loadEncryptionMetadata(EncryptedHeaderContentSupplier encryptedHeaderContentSupplier) throws IOException;
+
+    /**
+     * Few encryption algorithms have certain conditions on the unit of content to be encrypted. This requires the
+     * content size to be re adjusted in order to fulfil these conditions for partial writes. If write requests for
+     * encryption of a part of content do not fulfil these conditions then encryption fails or can result in corrupted
+     * content depending on the algorithm used. This method exposes a means to re-adjust sizes of such writes.
+     *
+     * @param cryptoContext crypto metadata instance
+     * @param contentSize Size of the raw content
+     * @return Adjusted size of the content.
+     */
+    long adjustContentSizeForPartialEncryption(T cryptoContext, long contentSize);
+
+    /**
+     * Estimate length of the encrypted content. It should only be used to determine length of entire content after
+     * encryption.
+     *
+     * @param cryptoContext crypto metadata instance consisting of encryption metadata used in encryption.
+     * @param contentLength Size of the raw content
+     * @return Calculated size of the encrypted content.
+     */
+    long estimateEncryptedLengthOfEntireContent(T cryptoContext, long contentLength);
+
+    /**
+     * For given encrypted content length, estimate the length of the decrypted content.
+     * @param cryptoContext crypto metadata instance consisting of encryption metadata used in encryption.
+     * @param contentLength Size of the encrypted content
+     * @return Calculated size of the decrypted content.
+     */
+    long estimateDecryptedLength(U cryptoContext, long contentLength);
+
+    /**
+     * Wraps a raw InputStream with encrypting stream
+     *
+     * @param encryptionMetadata created earlier to set the crypto metadata.
+     * @param stream Raw InputStream to encrypt
+     * @return encrypting stream wrapped around raw InputStream.
+     */
+    InputStreamContainer createEncryptingStream(T encryptionMetadata, InputStreamContainer stream);
+
+    /**
+     * Provides encrypted stream for a raw stream emitted for a part of content.
+     *
+     * @param cryptoContext crypto metadata instance.
+     * @param stream raw stream for which encrypted stream has to be created.
+     * @param totalStreams Number of streams being used for the entire content.
+     * @param streamIdx Index of the current stream.
+     * @return Encrypted stream for the provided raw stream.
+     */
+    InputStreamContainer createEncryptingStreamOfPart(T cryptoContext, InputStreamContainer stream, int totalStreams, int streamIdx);
+
+    /**
+     * This method accepts an encrypted stream and provides a decrypting wrapper.
+     * @param encryptingStream to be decrypted.
+     * @return Decrypting wrapper stream
+     */
+    InputStream createDecryptingStream(InputStream encryptingStream);
+
+    /**
+     * This method creates a {@link DecryptedRangedStreamProvider} which provides a wrapped stream to decrypt the
+     * underlying stream. This also provides adjusted range against the actual range which should be used for fetching
+     * and supplying the encrypted content for decryption. Extra content outside the range is trimmed down and returned
+     * by the decrypted stream.
+     * For partial reads of encrypted content, few algorithms require the range of content to be adjusted for
+     * successful decryption. Adjusted range may or may not be same as the provided range. If range is adjusted then
+     * starting offset of resultant range can be lesser than the starting offset of provided range and end
+     * offset can be greater than the ending offset of the provided range.
+     *
+     * @param cryptoContext crypto metadata instance.
+     * @param startPosOfRawContent starting position in the raw/decrypted content
+     * @param endPosOfRawContent ending position in the raw/decrypted content
+     */
+    DecryptedRangedStreamProvider createDecryptingStreamOfRange(U cryptoContext, long startPosOfRawContent, long endPosOfRawContent);
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/DataKeyPair.java b/libs/common/src/main/java/org/opensearch/common/crypto/DataKeyPair.java
new file mode 100644
index 0000000000000..711c0d314ecef
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/DataKeyPair.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.common.crypto;
+
+/**
+ * Key pair generated by {@link MasterKeyProvider}
+ */
+public class DataKeyPair {
+
+    /** Unencrypted data key used for encryption and decryption */
+    private final byte[] rawKey;
+    /** Encrypted version of rawKey */
+    private final byte[] encryptedKey;
+
+    /**
+     * Constructor to initialize key-pair values
+     * @param rawKey Unencrypted data key used for encryption and decryption
+     * @param encryptedKey Encrypted version of rawKey
+     */
+    public DataKeyPair(byte[] rawKey, byte[] encryptedKey) {
+        this.rawKey = rawKey;
+        this.encryptedKey = encryptedKey;
+    }
+
+    /**
+     * Returns Unencrypted data key
+     * @return raw/decrypted key
+     */
+    public byte[] getRawKey() {
+        return rawKey;
+    }
+
+    /**
+     * Returns encrypted key
+     * @return encrypted key
+     */
+    public byte[] getEncryptedKey() {
+        return encryptedKey;
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/DecryptedRangedStreamProvider.java b/libs/common/src/main/java/org/opensearch/common/crypto/DecryptedRangedStreamProvider.java
new file mode 100644
index 0000000000000..2cda3c1f8bdb4
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/DecryptedRangedStreamProvider.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.crypto;
+
+import java.io.InputStream;
+import java.util.function.UnaryOperator;
+
+/**
+ * Contains adjusted range of partial encrypted content which needs to be used for decryption.
+ */
+public class DecryptedRangedStreamProvider {
+
+    /** Adjusted range of partial encrypted content which needs to be used for decryption. */
+    private final long[] adjustedRange;
+    /** Stream provider for decryption and range re-adjustment. */
+    private final UnaryOperator<InputStream> decryptedStreamProvider;
+
+    /**
+     * To construct adjusted encrypted range.
+     * @param adjustedRange range of partial encrypted content which needs to be used for decryption.
+     * @param decryptedStreamProvider stream provider for decryption and range re-adjustment.
+     */
+    public DecryptedRangedStreamProvider(long[] adjustedRange, UnaryOperator<InputStream> decryptedStreamProvider) {
+        this.adjustedRange = adjustedRange;
+        this.decryptedStreamProvider = decryptedStreamProvider;
+    }
+
+    /**
+     * Adjusted range of partial encrypted content which needs to be used for decryption.
+     * @return adjusted range
+     */
+    public long[] getAdjustedRange() {
+        return adjustedRange;
+    }
+
+    /**
+     * A utility stream provider which supplies the stream responsible for decrypting the content and reading the
+     * desired range of decrypted content by skipping extra content which got decrypted as a result of range adjustment.
+     * @return stream provider for decryption and supplying the desired range of content.
+     */
+    public UnaryOperator<InputStream> getDecryptedStreamProvider() {
+        return decryptedStreamProvider;
+    }
+
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/EncryptedHeaderContentSupplier.java b/libs/common/src/main/java/org/opensearch/common/crypto/EncryptedHeaderContentSupplier.java
new file mode 100644
index 0000000000000..49a037f05f185
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/EncryptedHeaderContentSupplier.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.common.crypto;
+
+import java.io.IOException;
+
+/**
+ * This is used in partial decryption. Header information is required for decryption of actual encrypted content.
+ * Implementation of this supplier only requires first few bytes of encrypted content to be supplied.
+ */
+public interface EncryptedHeaderContentSupplier {
+
+    /**
+     * @param start Start position of the encrypted content (Generally supplied as 0 during usage)
+     * @param end End position of the header.
+     * @return Encrypted header content (May contain additional content which is later discarded)
+     * @throws IOException In case content fetch fails.
+     */
+    byte[] supply(long start, long end) throws IOException;
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/MasterKeyProvider.java b/libs/common/src/main/java/org/opensearch/common/crypto/MasterKeyProvider.java
new file mode 100644
index 0000000000000..8afa48eb92c0f
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/MasterKeyProvider.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.common.crypto;
+
+import java.io.Closeable;
+import java.util.Map;
+
+/**
+ * Master key provider responsible for management of master keys.
+ */
+public interface MasterKeyProvider extends Closeable {
+
+    /**
+     * Returns data key pair
+     * @return data key pair generated by master key.
+     */
+    DataKeyPair generateDataPair();
+
+    /**
+     * Returns decrypted key against the encrypted key.
+     * @param encryptedKey Key to decrypt
+     * @return Decrypted version of key.
+     */
+    byte[] decryptKey(byte[] encryptedKey);
+
+    /**
+     * Returns key id.
+     * @return key id
+     */
+    String getKeyId();
+
+    /**
+     * Returns encryption context associated with this master key.
+     * @return encryption context associated with this master key.
+     */
+    Map<String, String> getEncryptionContext();
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/crypto/package-info.java b/libs/common/src/main/java/org/opensearch/common/crypto/package-info.java
new file mode 100644
index 0000000000000..c744689ebf532
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/crypto/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common crypto utilities used across opensearch. */
+package org.opensearch.common.crypto;
diff --git a/libs/common/src/main/java/org/opensearch/common/hash/T1ha1.java b/libs/common/src/main/java/org/opensearch/common/hash/T1ha1.java
new file mode 100644
index 0000000000000..07b2306eda4e5
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/hash/T1ha1.java
@@ -0,0 +1,277 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import org.opensearch.common.annotation.InternalApi;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.invoke.VarHandle;
+import java.nio.ByteOrder;
+
+import static java.lang.Long.rotateRight;
+
+/**
+ * t1ha: Fast Positive Hash
+ *
+ * <p>
+ * Implements <a href="https://github.com/erthink/t1ha#t1ha1--64-bits-baseline-fast-portable-hash">t1ha1</a>;
+ * a fast portable hash function with reasonable quality for checksums, hash tables, and thin fingerprinting.
+ *
+ * <p>
+ * To overcome language and performance limitations, this implementation differs slightly from the
+ * <a href="https://github.com/erthink/t1ha/blob/master/src/t1ha1.c">reference implementation</a> in C++,
+ * so the returned values may vary before JDK 18.
+ *
+ * <p>
+ * Intended for little-endian systems but returns the same result on big-endian, albeit marginally slower.
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public final class T1ha1 {
+    private static final long SEED = System.nanoTime();
+    private static final Mux64 MUX_64_IMPL = fastestMux64Impl();
+
+    private static final VarHandle LONG_HANDLE = MethodHandles.byteArrayViewVarHandle(long[].class, ByteOrder.LITTLE_ENDIAN);
+    private static final VarHandle INT_HANDLE = MethodHandles.byteArrayViewVarHandle(int[].class, ByteOrder.LITTLE_ENDIAN);
+    private static final VarHandle SHORT_HANDLE = MethodHandles.byteArrayViewVarHandle(short[].class, ByteOrder.LITTLE_ENDIAN);
+
+    // "Magic" primes:
+    private static final long p0 = 0xEC99BF0D8372CAABL;
+    private static final long p1 = 0x82434FE90EDCEF39L;
+    private static final long p2 = 0xD4F06DB99D67BE4BL;
+    private static final long p3 = 0xBD9CACC22C6E9571L;
+    private static final long p4 = 0x9C06FAF4D023E3ABL;
+    private static final long p5 = 0xC060724A8424F345L;
+    private static final long p6 = 0xCB5AF53AE3AAAC31L;
+
+    // Rotations:
+    private static final int s0 = 41;
+    private static final int s1 = 17;
+    private static final int s2 = 31;
+
+    /**
+     * No public constructor.
+     */
+    private T1ha1() {}
+
+    /**
+     * Returns the hash code for the specified range of the given {@code byte} array.
+     * @param input the input byte array
+     * @param offset the starting offset
+     * @param length the length of the range
+     * @return hash code
+     */
+    public static long hash(byte[] input, int offset, int length) {
+        return hash(input, offset, length, SEED);
+    }
+
+    /**
+     * Returns the hash code for the specified range of the given {@code byte} array.
+     * @param input the input byte array
+     * @param offset the starting offset
+     * @param length the length of the range
+     * @param seed customized seed
+     * @return hash code
+     */
+    public static long hash(byte[] input, int offset, int length, long seed) {
+        long a = seed;
+        long b = length;
+
+        if (length > 32) {
+            long c = rotateRight(length, s1) + seed;
+            long d = length ^ rotateRight(seed, s1);
+
+            do {
+                long w0 = fetch64(input, offset);
+                long w1 = fetch64(input, offset + 8);
+                long w2 = fetch64(input, offset + 16);
+                long w3 = fetch64(input, offset + 24);
+
+                long d02 = w0 ^ rotateRight(w2 + d, s1);
+                long c13 = w1 ^ rotateRight(w3 + c, s1);
+                c += a ^ rotateRight(w0, s0);
+                d -= b ^ rotateRight(w1, s2);
+                a ^= p1 * (d02 + w3);
+                b ^= p0 * (c13 + w2);
+
+                offset += 32;
+                length -= 32;
+            } while (length >= 32);
+
+            a ^= p6 * (rotateRight(c, s1) + d);
+            b ^= p5 * (rotateRight(d, s1) + c);
+        }
+
+        return h32(input, offset, length, a, b);
+    }
+
+    /**
+     * Computes the hash of up to 32 bytes.
+     * Constants in the switch expression are dense; JVM will use them as indices into a table of
+     * instruction pointers (tableswitch instruction), making lookups really fast.
+     */
+    @SuppressWarnings("fallthrough")
+    private static long h32(byte[] input, int offset, int length, long a, long b) {
+        switch (length) {
+            default:
+                b += mux64(fetch64(input, offset), p4);
+                offset += 8;
+                length -= 8;
+            case 24:
+            case 23:
+            case 22:
+            case 21:
+            case 20:
+            case 19:
+            case 18:
+            case 17:
+                a += mux64(fetch64(input, offset), p3);
+                offset += 8;
+                length -= 8;
+            case 16:
+            case 15:
+            case 14:
+            case 13:
+            case 12:
+            case 11:
+            case 10:
+            case 9:
+                b += mux64(fetch64(input, offset), p2);
+                offset += 8;
+                length -= 8;
+            case 8:
+            case 7:
+            case 6:
+            case 5:
+            case 4:
+            case 3:
+            case 2:
+            case 1:
+                a += mux64(tail64(input, offset, length), p1);
+            case 0:
+                // Final weak avalanche
+                return mux64(rotateRight(a + b, s1), p4) + mix64(a ^ b, p0);
+        }
+    }
+
+    /**
+     * XOR the high and low parts of the full 128-bit product.
+     */
+    private static long mux64(long a, long b) {
+        return MUX_64_IMPL.mux64(a, b);
+    }
+
+    /**
+     * XOR-MUL-XOR bit-mixer.
+     */
+    private static long mix64(long a, long b) {
+        a *= b;
+        return a ^ rotateRight(a, s0);
+    }
+
+    /**
+     * Reads "length" bytes starting at "offset" in little-endian order; returned as long.
+     * It is assumed that the length is between 1 and 8 (inclusive); but no defensive checks are made as such.
+     */
+    private static long tail64(byte[] input, int offset, int length) {
+        switch (length) {
+            case 1:
+                return fetch8(input, offset);
+            case 2:
+                return fetch16(input, offset);
+            case 3:
+                return fetch16(input, offset) | (fetch8(input, offset + 2) << 16);
+            case 4:
+                return fetch32(input, offset);
+            case 5:
+                return fetch32(input, offset) | (fetch8(input, offset + 4) << 32);
+            case 6:
+                return fetch32(input, offset) | (fetch16(input, offset + 4) << 32);
+            case 7:
+                // This is equivalent to:
+                // return fetch32(input, offset) | (fetch16(input, offset + 4) << 32) | (fetch8(input, offset + 6) << 48);
+                // But reading two ints overlapping by one byte is faster due to lesser instructions.
+                return fetch32(input, offset) | (fetch32(input, offset + 3) << 24);
+            default:
+                return fetch64(input, offset);
+        }
+    }
+
+    /**
+     * Reads a 64-bit long.
+     */
+    private static long fetch64(byte[] input, int offset) {
+        return (long) LONG_HANDLE.get(input, offset);
+    }
+
+    /**
+     * Reads a 32-bit unsigned integer, returned as long.
+     */
+    private static long fetch32(byte[] input, int offset) {
+        return (int) INT_HANDLE.get(input, offset) & 0xFFFFFFFFL;
+    }
+
+    /**
+     * Reads a 16-bit unsigned short, returned as long.
+     */
+    private static long fetch16(byte[] input, int offset) {
+        return (short) SHORT_HANDLE.get(input, offset) & 0xFFFFL;
+    }
+
+    /**
+     * Reads an 8-bit unsigned byte, returned as long.
+     */
+    private static long fetch8(byte[] input, int offset) {
+        return input[offset] & 0xFFL;
+    }
+
+    /**
+     * The implementation of mux64.
+     */
+    @FunctionalInterface
+    private interface Mux64 {
+        long mux64(long a, long b);
+    }
+
+    /**
+     * Provides the fastest available implementation of mux64 on this platform.
+     *
+     * <p>
+     * Ideally, the following should be returned to match the reference implementation:
+     * {@code Math.unsignedMultiplyHigh(a, b) ^ (a * b)}
+     *
+     * <p>
+     * Since unsignedMultiplyHigh isn't available before JDK 18, and calculating it without intrinsics is quite slow,
+     * the multiplyHigh method is used instead. Slight loss in quality is imperceptible for our use-case: a hash table.
+     * {@code Math.multiplyHigh(a, b) ^ (a * b)}
+     *
+     * <p>
+     * This indirection can be removed once we stop supporting older JDKs.
+     */
+    private static Mux64 fastestMux64Impl() {
+        try {
+            final MethodHandle unsignedMultiplyHigh = MethodHandles.publicLookup()
+                .findStatic(Math.class, "unsignedMultiplyHigh", MethodType.methodType(long.class, long.class, long.class));
+            return (a, b) -> {
+                try {
+                    return (long) unsignedMultiplyHigh.invokeExact(a, b) ^ (a * b);
+                } catch (Throwable e) {
+                    throw new RuntimeException(e);
+                }
+            };
+        } catch (NoSuchMethodException e) {
+            return (a, b) -> Math.multiplyHigh(a, b) ^ (a * b);
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/hash/package-info.java b/libs/common/src/main/java/org/opensearch/common/hash/package-info.java
new file mode 100644
index 0000000000000..bd393b8b921ed
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/hash/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Common hashing utilities.
+ */
+package org.opensearch.common.hash;
diff --git a/libs/common/src/main/java/org/opensearch/common/io/InputStreamContainer.java b/libs/common/src/main/java/org/opensearch/common/io/InputStreamContainer.java
new file mode 100644
index 0000000000000..eb8a4e1382497
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/io/InputStreamContainer.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.io;
+
+import java.io.InputStream;
+
+/**
+ * Model composed of an input stream and the total content length of the stream
+ *
+ * @opensearch.internal
+ */
+public class InputStreamContainer {
+
+    private final InputStream inputStream;
+    private final long contentLength;
+    private final long offset;
+
+    /**
+     * Construct a new stream object
+     *
+     * @param inputStream   The input stream that is to be encapsulated
+     * @param contentLength The total content length that is to be read from the stream
+     */
+    public InputStreamContainer(InputStream inputStream, long contentLength, long offset) {
+        this.inputStream = inputStream;
+        this.contentLength = contentLength;
+        this.offset = offset;
+    }
+
+    /**
+     * @return The input stream this object is reading from
+     */
+    public InputStream getInputStream() {
+        return inputStream;
+    }
+
+    /**
+     * @return The total length of the content that has to be read from this stream
+     */
+    public long getContentLength() {
+        return contentLength;
+    }
+
+    /**
+     * @return offset of the source content.
+     */
+    public long getOffset() {
+        return offset;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/common/io/PathUtils.java b/libs/common/src/main/java/org/opensearch/common/io/PathUtils.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/io/PathUtils.java
rename to libs/common/src/main/java/org/opensearch/common/io/PathUtils.java
index 85b623ef4d06d..b3526859933ec 100644
--- a/libs/core/src/main/java/org/opensearch/common/io/PathUtils.java
+++ b/libs/common/src/main/java/org/opensearch/common/io/PathUtils.java
@@ -46,6 +46,8 @@
  * <p>
  * This class allows the default filesystem to
  * be changed during tests.
+ *
+ * @opensearch.internal
  */
 @SuppressForbidden(reason = "accesses the default filesystem by design")
 // TODO: can we move this to the .env package and make it package-private?
diff --git a/libs/common/src/main/java/org/opensearch/common/io/package-info.java b/libs/common/src/main/java/org/opensearch/common/io/package-info.java
new file mode 100644
index 0000000000000..e79aeb830761b
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/io/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common i/o utilities used across opensearch. */
+package org.opensearch.common.io;
diff --git a/server/src/main/java/org/opensearch/common/lease/Releasable.java b/libs/common/src/main/java/org/opensearch/common/lease/Releasable.java
similarity index 89%
rename from server/src/main/java/org/opensearch/common/lease/Releasable.java
rename to libs/common/src/main/java/org/opensearch/common/lease/Releasable.java
index e7f854d7d10b2..30bea6185febc 100644
--- a/server/src/main/java/org/opensearch/common/lease/Releasable.java
+++ b/libs/common/src/main/java/org/opensearch/common/lease/Releasable.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common.lease;
 
-import org.opensearch.OpenSearchException;
-
 import java.io.Closeable;
 
 /**
- * Specialization of {@link AutoCloseable} that may only throw an {@link OpenSearchException}.
+ * Specialization of {@link AutoCloseable} for calls that might not throw a checked exception.
+ *
+ * @opensearch.internal
  */
 public interface Releasable extends Closeable {
 
diff --git a/server/src/main/java/org/opensearch/common/lease/Releasables.java b/libs/common/src/main/java/org/opensearch/common/lease/Releasables.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/lease/Releasables.java
rename to libs/common/src/main/java/org/opensearch/common/lease/Releasables.java
index bed26c6facd36..31bfa9a2dd7ab 100644
--- a/server/src/main/java/org/opensearch/common/lease/Releasables.java
+++ b/libs/common/src/main/java/org/opensearch/common/lease/Releasables.java
@@ -33,14 +33,18 @@
 package org.opensearch.common.lease;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.Arrays;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-/** Utility methods to work with {@link Releasable}s. */
+/**
+ * Utility methods to work with {@link Releasable}s.
+ *
+ * @opensearch.internal
+ */
 public enum Releasables {
     ;
 
diff --git a/libs/common/src/main/java/org/opensearch/common/lease/package-info.java b/libs/common/src/main/java/org/opensearch/common/lease/package-info.java
new file mode 100644
index 0000000000000..f7097486a9c64
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/lease/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Releasables package. */
+package org.opensearch.common.lease;
diff --git a/server/src/main/java/org/opensearch/common/component/AbstractLifecycleComponent.java b/libs/common/src/main/java/org/opensearch/common/lifecycle/AbstractLifecycleComponent.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/component/AbstractLifecycleComponent.java
rename to libs/common/src/main/java/org/opensearch/common/lifecycle/AbstractLifecycleComponent.java
index cae81cb0931b3..111556fbe43cf 100644
--- a/server/src/main/java/org/opensearch/common/component/AbstractLifecycleComponent.java
+++ b/libs/common/src/main/java/org/opensearch/common/lifecycle/AbstractLifecycleComponent.java
@@ -30,13 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.component;
+package org.opensearch.common.lifecycle;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 
+/**
+ * Base class for a lifecycle component.
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractLifecycleComponent implements LifecycleComponent {
 
     protected final Lifecycle lifecycle = new Lifecycle();
diff --git a/server/src/main/java/org/opensearch/common/component/Lifecycle.java b/libs/common/src/main/java/org/opensearch/common/lifecycle/Lifecycle.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/component/Lifecycle.java
rename to libs/common/src/main/java/org/opensearch/common/lifecycle/Lifecycle.java
index afeb3c97cc027..c1cf9b2998a13 100644
--- a/server/src/main/java/org/opensearch/common/component/Lifecycle.java
+++ b/libs/common/src/main/java/org/opensearch/common/lifecycle/Lifecycle.java
@@ -30,7 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.component;
+package org.opensearch.common.lifecycle;
+
+import org.opensearch.common.annotation.PublicApi;
 
 /**
  * Lifecycle state. Allows the following transitions:
@@ -72,9 +74,18 @@
  *  // perform close logic here
  * }
  * </pre>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class Lifecycle {
 
+    /**
+     * State in the lifecycle
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public enum State {
         INITIALIZED,
         STOPPED,
diff --git a/server/src/main/java/org/opensearch/common/component/LifecycleComponent.java b/libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleComponent.java
similarity index 87%
rename from server/src/main/java/org/opensearch/common/component/LifecycleComponent.java
rename to libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleComponent.java
index d0691c54dc220..781c276fefe13 100644
--- a/server/src/main/java/org/opensearch/common/component/LifecycleComponent.java
+++ b/libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleComponent.java
@@ -30,10 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.component;
+package org.opensearch.common.lifecycle;
 
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.lease.Releasable;
 
+/**
+ * Base interface for a lifecycle component.
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public interface LifecycleComponent extends Releasable {
 
     Lifecycle.State lifecycleState();
diff --git a/server/src/main/java/org/opensearch/common/component/LifecycleListener.java b/libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleListener.java
similarity index 92%
rename from server/src/main/java/org/opensearch/common/component/LifecycleListener.java
rename to libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleListener.java
index dedf9a4899739..7ac41a5eb0df0 100644
--- a/server/src/main/java/org/opensearch/common/component/LifecycleListener.java
+++ b/libs/common/src/main/java/org/opensearch/common/lifecycle/LifecycleListener.java
@@ -30,8 +30,13 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.component;
+package org.opensearch.common.lifecycle;
 
+/**
+ * Base lifecycle listener.
+ *
+ * @opensearch.internal
+ */
 public abstract class LifecycleListener {
 
     public void beforeStart() {
diff --git a/libs/common/src/main/java/org/opensearch/common/lifecycle/package-info.java b/libs/common/src/main/java/org/opensearch/common/lifecycle/package-info.java
new file mode 100644
index 0000000000000..1bedde5585e36
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/lifecycle/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Foundation implementation for a object lifecycle.
+ *
+ * See {@link org.opensearch.common.lifecycle.Lifecycle} for example usage
+ *
+ * @opensearch.internal
+ */
+package org.opensearch.common.lifecycle;
diff --git a/server/src/main/java/org/opensearch/common/network/Cidrs.java b/libs/common/src/main/java/org/opensearch/common/network/Cidrs.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/network/Cidrs.java
rename to libs/common/src/main/java/org/opensearch/common/network/Cidrs.java
index 86034fa8cac9c..651ab8883a9aa 100644
--- a/server/src/main/java/org/opensearch/common/network/Cidrs.java
+++ b/libs/common/src/main/java/org/opensearch/common/network/Cidrs.java
@@ -36,6 +36,11 @@
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * Network Cidrs
+ *
+ * @opensearch.internal
+ */
 public final class Cidrs {
     private Cidrs() {}
 
diff --git a/server/src/main/java/org/opensearch/common/network/InetAddresses.java b/libs/common/src/main/java/org/opensearch/common/network/InetAddresses.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/network/InetAddresses.java
rename to libs/common/src/main/java/org/opensearch/common/network/InetAddresses.java
index 87a18f41deecc..a4fbc6cb65b0d 100644
--- a/server/src/main/java/org/opensearch/common/network/InetAddresses.java
+++ b/libs/common/src/main/java/org/opensearch/common/network/InetAddresses.java
@@ -39,6 +39,11 @@
 import java.util.Arrays;
 import java.util.Locale;
 
+/**
+ * Network addresses.
+ *
+ * @opensearch.internal
+ */
 public class InetAddresses {
     private static int IPV4_PART_COUNT = 4;
     private static int IPV6_PART_COUNT = 8;
diff --git a/server/src/main/java/org/opensearch/common/network/NetworkAddress.java b/libs/common/src/main/java/org/opensearch/common/network/NetworkAddress.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/network/NetworkAddress.java
rename to libs/common/src/main/java/org/opensearch/common/network/NetworkAddress.java
index 324e35f683a11..f5bc3face6e45 100644
--- a/server/src/main/java/org/opensearch/common/network/NetworkAddress.java
+++ b/libs/common/src/main/java/org/opensearch/common/network/NetworkAddress.java
@@ -60,6 +60,8 @@
  * This class provides sane address formatting instead, e.g.
  * {@code 127.0.0.1} and {@code ::1} respectively. No methods do reverse
  * lookups.
+ *
+ * @opensearch.internal
  */
 public final class NetworkAddress {
     /** No instantiation */
diff --git a/libs/common/src/main/java/org/opensearch/common/network/package-info.java b/libs/common/src/main/java/org/opensearch/common/network/package-info.java
new file mode 100644
index 0000000000000..92e4eac5bde42
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/network/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** common network layer classes used across the code base */
+package org.opensearch.common.network;
diff --git a/libs/common/src/main/java/org/opensearch/common/package-info.java b/libs/common/src/main/java/org/opensearch/common/package-info.java
new file mode 100644
index 0000000000000..f91bac5192f63
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common Library of Utilties and Data Structures used across OpenSearch. */
+package org.opensearch.common;
diff --git a/server/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java
index 66adee7ae45f0..321062556ef86 100644
--- a/server/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecycler.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.recycler;
 
+/**
+ * Base recycler.
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractRecycler<T> implements Recycler<T> {
 
     protected final Recycler.C<T> c;
diff --git a/server/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java b/libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java
index 16a85ad6eda7f..8957880c27cdf 100644
--- a/server/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/AbstractRecyclerC.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.recycler;
 
+/**
+ * Base recycler.
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractRecyclerC<T> implements Recycler.C<T> {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java
index c279a554890a2..68d108d58603f 100644
--- a/server/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/ConcurrentDequeRecycler.java
@@ -39,6 +39,8 @@
 
 /**
  * A {@link Recycler} implementation based on a concurrent {@link Deque}. This implementation is thread-safe.
+ *
+ * @opensearch.internal
  */
 public class ConcurrentDequeRecycler<T> extends DequeRecycler<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/recycler/DequeRecycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/DequeRecycler.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/recycler/DequeRecycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/DequeRecycler.java
index 44a6c86f791a7..1d6588119e7f5 100644
--- a/server/src/main/java/org/opensearch/common/recycler/DequeRecycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/DequeRecycler.java
@@ -36,6 +36,8 @@
 
 /**
  * A {@link Recycler} implementation based on a {@link Deque}. This implementation is NOT thread-safe.
+ *
+ * @opensearch.internal
  */
 public class DequeRecycler<T> extends AbstractRecycler<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/recycler/FilterRecycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/FilterRecycler.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/recycler/FilterRecycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/FilterRecycler.java
index 77a9a8cbc224d..e3825eb53c501 100644
--- a/server/src/main/java/org/opensearch/common/recycler/FilterRecycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/FilterRecycler.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.recycler;
 
+/**
+ * Base filter recycler.
+ *
+ * @opensearch.internal
+ */
 abstract class FilterRecycler<T> implements Recycler<T> {
 
     /** Get the delegate instance to forward calls to. */
diff --git a/server/src/main/java/org/opensearch/common/recycler/NoneRecycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/NoneRecycler.java
similarity index 93%
rename from server/src/main/java/org/opensearch/common/recycler/NoneRecycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/NoneRecycler.java
index cab62c7fc218d..d3d74138d3d6a 100644
--- a/server/src/main/java/org/opensearch/common/recycler/NoneRecycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/NoneRecycler.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.recycler;
 
+/**
+ * No value recycler
+ *
+ * @opensearch.internal
+ */
 public class NoneRecycler<T> extends AbstractRecycler<T> {
 
     public NoneRecycler(C<T> c) {
@@ -43,6 +48,11 @@ public V<T> obtain() {
         return new NV<>(c.newInstance());
     }
 
+    /**
+     * Generic no value recycler
+     *
+     * @opensearch.internal
+     */
     public static class NV<T> implements Recycler.V<T> {
 
         T value;
diff --git a/server/src/main/java/org/opensearch/common/recycler/Recycler.java b/libs/common/src/main/java/org/opensearch/common/recycler/Recycler.java
similarity index 88%
rename from server/src/main/java/org/opensearch/common/recycler/Recycler.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/Recycler.java
index e700a324f38f3..0b0c98772a77c 100644
--- a/server/src/main/java/org/opensearch/common/recycler/Recycler.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/Recycler.java
@@ -37,13 +37,25 @@
 /**
  * A recycled object, note, implementations should support calling obtain and then recycle
  * on different threads.
+ *
+ * @opensearch.internal
  */
 public interface Recycler<T> {
 
+    /**
+     * Base factory interface
+     *
+     * @opensearch.internal
+     */
     interface Factory<T> {
         Recycler<T> build();
     }
 
+    /**
+     * Generic for recycler
+     *
+     * @opensearch.internal
+     */
     interface C<T> {
 
         /** Create a new empty instance of the given size. */
@@ -56,6 +68,11 @@ interface C<T> {
         void destroy(T value);
     }
 
+    /**
+     * Generic releasable
+     *
+     * @opensearch.internal
+     */
     interface V<T> extends Releasable {
 
         /** Reference to the value. */
diff --git a/server/src/main/java/org/opensearch/common/recycler/Recyclers.java b/libs/common/src/main/java/org/opensearch/common/recycler/Recyclers.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/recycler/Recyclers.java
rename to libs/common/src/main/java/org/opensearch/common/recycler/Recyclers.java
index 6f7a254ec015c..52587144369f1 100644
--- a/server/src/main/java/org/opensearch/common/recycler/Recyclers.java
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/Recyclers.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.common.recycler;
 
-import com.carrotsearch.hppc.BitMixer;
+import org.opensearch.common.util.BitMixer;
 
 import java.util.ArrayDeque;
 
+/**
+ * Utility class of recyclers.
+ *
+ * @opensearch.internal
+ */
 public enum Recyclers {
     ;
 
@@ -70,6 +75,8 @@ public static <T> Recycler.Factory<T> dequeFactory(final Recycler.C<T> c, final
     /**
      * Wrap the provided recycler so that calls to {@link Recycler#obtain()} and {@link Recycler.V#close()} are protected by
      * a lock.
+     *
+     * @opensearch.internal
      */
     public static <T> Recycler<T> locked(final Recycler<T> recycler) {
         return new FilterRecycler<T>() {
@@ -135,7 +142,7 @@ public static <T> Recycler<T> concurrent(final Recycler.Factory<T> factory, fina
             private final Recycler<T>[] recyclers;
 
             {
-                @SuppressWarnings("unchecked")
+                @SuppressWarnings({ "rawtypes", "unchecked" })
                 final Recycler<T>[] recyclers = new Recycler[concurrencyLevel];
                 this.recyclers = recyclers;
                 for (int i = 0; i < concurrencyLevel; ++i) {
diff --git a/libs/common/src/main/java/org/opensearch/common/recycler/package-info.java b/libs/common/src/main/java/org/opensearch/common/recycler/package-info.java
new file mode 100644
index 0000000000000..fec3c5d5e52d3
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/recycler/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common Recycler functionality for recycling objects */
+package org.opensearch.common.recycler;
diff --git a/server/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java b/libs/common/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java
rename to libs/common/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java
index c950749b4979d..72f8146cb969d 100644
--- a/server/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java
+++ b/libs/common/src/main/java/org/opensearch/common/transport/NetworkExceptionHelper.java
@@ -35,6 +35,11 @@
 import java.net.ConnectException;
 import java.nio.channels.ClosedChannelException;
 
+/**
+ * Helper class for network exceptions.
+ *
+ * @opensearch.internal
+ */
 public class NetworkExceptionHelper {
 
     public static boolean isConnectException(Throwable e) {
diff --git a/server/src/main/java/org/opensearch/common/transport/PortsRange.java b/libs/common/src/main/java/org/opensearch/common/transport/PortsRange.java
similarity index 87%
rename from server/src/main/java/org/opensearch/common/transport/PortsRange.java
rename to libs/common/src/main/java/org/opensearch/common/transport/PortsRange.java
index c2f164680463a..daf3e00c062fa 100644
--- a/server/src/main/java/org/opensearch/common/transport/PortsRange.java
+++ b/libs/common/src/main/java/org/opensearch/common/transport/PortsRange.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.common.transport;
 
-import com.carrotsearch.hppc.IntArrayList;
-
+import java.util.ArrayList;
+import java.util.List;
 import java.util.StringTokenizer;
 
+/**
+ * Port range utility classes
+ *
+ * @opensearch.internal
+ */
 public class PortsRange {
 
     private final String portRange;
@@ -49,15 +54,12 @@ public String getPortRangeString() {
     }
 
     public int[] ports() throws NumberFormatException {
-        final IntArrayList ports = new IntArrayList();
-        iterate(new PortCallback() {
-            @Override
-            public boolean onPortNumber(int portNumber) {
-                ports.add(portNumber);
-                return false;
-            }
+        final List<Integer> ports = new ArrayList<>();
+        iterate(portNumber -> {
+            ports.add(portNumber);
+            return false;
         });
-        return ports.toArray();
+        return ports.stream().mapToInt(Integer::intValue).toArray();
     }
 
     public boolean iterate(PortCallback callback) throws NumberFormatException {
@@ -89,6 +91,11 @@ public boolean iterate(PortCallback callback) throws NumberFormatException {
         return success;
     }
 
+    /**
+     * Callback for the port
+     *
+     * @opensearch.internal
+     */
     public interface PortCallback {
         boolean onPortNumber(int portNumber);
     }
diff --git a/libs/common/src/main/java/org/opensearch/common/transport/package-info.java b/libs/common/src/main/java/org/opensearch/common/transport/package-info.java
new file mode 100644
index 0000000000000..7d28ac6c60a14
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/transport/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** common transport layer classes used across the code base */
+package org.opensearch.common.transport;
diff --git a/libs/core/src/main/java/org/opensearch/common/unit/TimeValue.java b/libs/common/src/main/java/org/opensearch/common/unit/TimeValue.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/unit/TimeValue.java
rename to libs/common/src/main/java/org/opensearch/common/unit/TimeValue.java
index ee150bf4ff85a..a3fcffb1d6a4c 100644
--- a/libs/core/src/main/java/org/opensearch/common/unit/TimeValue.java
+++ b/libs/common/src/main/java/org/opensearch/common/unit/TimeValue.java
@@ -32,10 +32,18 @@
 
 package org.opensearch.common.unit;
 
+import org.opensearch.common.annotation.PublicApi;
+
 import java.util.Locale;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Time value unit of measurement
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class TimeValue implements Comparable<TimeValue> {
 
     /** How many nano-seconds in one milli-second */
diff --git a/libs/common/src/main/java/org/opensearch/common/unit/package-info.java b/libs/common/src/main/java/org/opensearch/common/unit/package-info.java
new file mode 100644
index 0000000000000..f2387c4349cc5
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/unit/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common units of measurement used across opensearch. */
+package org.opensearch.common.unit;
diff --git a/libs/common/src/main/java/org/opensearch/common/util/BitMixer.java b/libs/common/src/main/java/org/opensearch/common/util/BitMixer.java
new file mode 100644
index 0000000000000..8762217916c7a
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/BitMixer.java
@@ -0,0 +1,172 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * HPPC
+ *
+ * Copyright (C) 2010-2022 Carrot Search s.c.
+ * All rights reserved.
+ *
+ * Refer to the full license file "LICENSE.txt":
+ * https://github.com/carrotsearch/hppc/blob/master/LICENSE.txt
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.util;
+
+/**
+ * Bit mixing utilities from carrotsearch.hppc.
+ *
+ * Licensed under ALv2. This is pulled in directly to avoid a full hppc dependency.
+ *
+ * The purpose of these methods is to evenly distribute key space over int32
+ * range.
+ */
+public final class BitMixer {
+
+    // Don't bother mixing very small key domains much.
+    public static int mix(byte key) {
+        return key * PHI_C32;
+    }
+
+    public static int mix(byte key, int seed) {
+        return (key ^ seed) * PHI_C32;
+    }
+
+    public static int mix(short key) {
+        return mixPhi(key);
+    }
+
+    public static int mix(short key, int seed) {
+        return mixPhi(key ^ seed);
+    }
+
+    public static int mix(char key) {
+        return mixPhi(key);
+    }
+
+    public static int mix(char key, int seed) {
+        return mixPhi(key ^ seed);
+    }
+
+    // Better mix for larger key domains.
+    public static int mix(int key) {
+        return mix32(key);
+    }
+
+    public static int mix(int key, int seed) {
+        return mix32(key ^ seed);
+    }
+
+    public static int mix(float key) {
+        return mix32(Float.floatToIntBits(key));
+    }
+
+    public static int mix(float key, int seed) {
+        return mix32(Float.floatToIntBits(key) ^ seed);
+    }
+
+    public static int mix(double key) {
+        return (int) mix64(Double.doubleToLongBits(key));
+    }
+
+    public static int mix(double key, int seed) {
+        return (int) mix64(Double.doubleToLongBits(key) ^ seed);
+    }
+
+    public static int mix(long key) {
+        return (int) mix64(key);
+    }
+
+    public static int mix(long key, int seed) {
+        return (int) mix64(key ^ seed);
+    }
+
+    public static int mix(Object key) {
+        return key == null ? 0 : mix32(key.hashCode());
+    }
+
+    public static int mix(Object key, int seed) {
+        return key == null ? 0 : mix32(key.hashCode() ^ seed);
+    }
+
+    /**
+     * MH3's plain finalization step.
+     */
+    public static int mix32(int k) {
+        k = (k ^ (k >>> 16)) * 0x85ebca6b;
+        k = (k ^ (k >>> 13)) * 0xc2b2ae35;
+        return k ^ (k >>> 16);
+    }
+
+    /**
+     * Computes David Stafford variant 9 of 64bit mix function (MH3 finalization step,
+     * with different shifts and constants).
+     *
+     * Variant 9 is picked because it contains two 32-bit shifts which could be possibly
+     * optimized into better machine code.
+     *
+     * @see "http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html"
+     */
+    public static long mix64(long z) {
+        z = (z ^ (z >>> 32)) * 0x4cd6944c5cc20b6dL;
+        z = (z ^ (z >>> 29)) * 0xfc12c5b19d3259e9L;
+        return z ^ (z >>> 32);
+    }
+
+    /*
+     * Golden ratio bit mixers.
+     */
+
+    private static final int PHI_C32 = 0x9e3779b9;
+    private static final long PHI_C64 = 0x9e3779b97f4a7c15L;
+
+    public static int mixPhi(byte k) {
+        final int h = k * PHI_C32;
+        return h ^ (h >>> 16);
+    }
+
+    public static int mixPhi(char k) {
+        final int h = k * PHI_C32;
+        return h ^ (h >>> 16);
+    }
+
+    public static int mixPhi(short k) {
+        final int h = k * PHI_C32;
+        return h ^ (h >>> 16);
+    }
+
+    public static int mixPhi(int k) {
+        final int h = k * PHI_C32;
+        return h ^ (h >>> 16);
+    }
+
+    public static int mixPhi(float k) {
+        final int h = Float.floatToIntBits(k) * PHI_C32;
+        return h ^ (h >>> 16);
+    }
+
+    public static int mixPhi(double k) {
+        final long h = Double.doubleToLongBits(k) * PHI_C64;
+        return (int) (h ^ (h >>> 32));
+    }
+
+    public static int mixPhi(long k) {
+        final long h = k * PHI_C64;
+        return (int) (h ^ (h >>> 32));
+    }
+
+    public static int mixPhi(Object k) {
+        final int h = (k == null ? 0 : k.hashCode() * PHI_C32);
+        return h ^ (h >>> 16);
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/common/util/FastMath.java b/libs/common/src/main/java/org/opensearch/common/util/FastMath.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/util/FastMath.java
rename to libs/common/src/main/java/org/opensearch/common/util/FastMath.java
index f3b04fda2cadb..ac95a39698787 100644
--- a/libs/core/src/main/java/org/opensearch/common/util/FastMath.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/FastMath.java
@@ -47,6 +47,8 @@
 
 /**
  * Additions or modifications to this class should only come from the original org.math.plot.utils.FastMath source
+ *
+ * @opensearch.api
  */
 final class FastMath {
 
diff --git a/libs/core/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java b/libs/common/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java
rename to libs/common/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java
index 4c24e87fe74b4..154b9c3a3ffc8 100644
--- a/libs/core/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/OpenSearchSloppyMath.java
@@ -34,6 +34,8 @@
 
 /**
  * Similar to Lucene's SloppyMath, but for additional math functions.
+ *
+ * @opensearch.api
  */
 public class OpenSearchSloppyMath {
 
diff --git a/libs/core/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java
rename to libs/common/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java
index e55c87c34c795..2e23e87bea534 100644
--- a/libs/core/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/AbstractRefCounted.java
@@ -38,6 +38,8 @@
  * A basic RefCounted implementation that is initialized with a
  * ref count of 1 and calls {@link #closeInternal()} once it reaches
  * a 0 ref count
+ *
+ * @opensearch.api
  */
 public abstract class AbstractRefCounted implements RefCounted {
     private final AtomicInteger refCount = new AtomicInteger(1);
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java
rename to libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java
index 758682fb9ff96..c646d476e17ab 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentCollections.java
@@ -43,6 +43,11 @@
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.LinkedTransferQueue;
 
+/**
+ * Thread safe collection base class.
+ *
+ * @opensearch.internal
+ */
 public abstract class ConcurrentCollections {
 
     static final int aggressiveConcurrencyLevel;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java
similarity index 98%
rename from server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java
rename to libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java
index d93d55d106e6e..6ee1b0a38248a 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentHashMapLong.java
@@ -37,6 +37,11 @@
 import java.util.Set;
 import java.util.concurrent.ConcurrentMap;
 
+/**
+ * Thread safe hash map of longs.
+ *
+ * @opensearch.internal
+ */
 public class ConcurrentHashMapLong<T> implements ConcurrentMapLong<T> {
 
     private final ConcurrentMap<Long, T> map;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java
rename to libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java
index fb1c752dd7a55..7656a957dc534 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/ConcurrentMapLong.java
@@ -34,6 +34,11 @@
 
 import java.util.concurrent.ConcurrentMap;
 
+/**
+ * Thread safe long value hash map
+ *
+ * @opensearch.internal
+ */
 public interface ConcurrentMapLong<T> extends ConcurrentMap<Long, T> {
 
     T get(long key);
diff --git a/libs/core/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java
rename to libs/common/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java
index 20a2222614343..1153df7225a05 100644
--- a/libs/core/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/RefCounted.java
@@ -49,6 +49,8 @@
  *          inst.decRef();
  *      }
  * </pre>
+ *
+ * @opensearch.api
  */
 public interface RefCounted {
 
diff --git a/libs/common/src/main/java/org/opensearch/common/util/concurrent/package-info.java b/libs/common/src/main/java/org/opensearch/common/util/concurrent/package-info.java
new file mode 100644
index 0000000000000..b17aeac7e4c4e
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/concurrent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common concurrency utilities used across opensearch. */
+package org.opensearch.common.util.concurrent;
diff --git a/libs/core/src/main/java/org/opensearch/core/internal/io/IOUtils.java b/libs/common/src/main/java/org/opensearch/common/util/io/IOUtils.java
similarity index 99%
rename from libs/core/src/main/java/org/opensearch/core/internal/io/IOUtils.java
rename to libs/common/src/main/java/org/opensearch/common/util/io/IOUtils.java
index 00ecb8b82d744..6b72a0f92c14d 100644
--- a/libs/core/src/main/java/org/opensearch/core/internal/io/IOUtils.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/io/IOUtils.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.core.internal.io;
+package org.opensearch.common.util.io;
 
 import org.opensearch.common.Nullable;
 
@@ -52,6 +52,8 @@
 
 /**
  * Utilities for common I/O methods. Borrowed heavily from Lucene (org.apache.lucene.util.IOUtils).
+ *
+ * @opensearch.internal
  */
 public final class IOUtils {
 
diff --git a/libs/common/src/main/java/org/opensearch/common/util/io/Streams.java b/libs/common/src/main/java/org/opensearch/common/util/io/Streams.java
new file mode 100644
index 0000000000000..96672a3be3dc1
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/io/Streams.java
@@ -0,0 +1,103 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.util.io;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Simple utility methods for file and stream copying.
+ * All copy methods close all affected streams when done.
+ * <p>
+ * Mainly for use within the framework,
+ * but also useful for application code.
+ *
+ * @opensearch.internal
+ */
+public abstract class Streams {
+
+    private static final ThreadLocal<byte[]> buffer = ThreadLocal.withInitial(() -> new byte[8 * 1024]);
+
+    /**
+     * Copy the contents of the given InputStream to the given OutputStream. Optionally, closes both streams when done.
+     *
+     * @param in     the stream to copy from
+     * @param out    the stream to copy to
+     * @param close  whether to close both streams after copying
+     * @param buffer buffer to use for copying
+     * @return the number of bytes copied
+     * @throws IOException in case of I/O errors
+     */
+    public static long copy(final InputStream in, final OutputStream out, byte[] buffer, boolean close) throws IOException {
+        Exception err = null;
+        try {
+            long byteCount = 0;
+            int bytesRead;
+            while ((bytesRead = in.read(buffer)) != -1) {
+                out.write(buffer, 0, bytesRead);
+                byteCount += bytesRead;
+            }
+            out.flush();
+            return byteCount;
+        } catch (IOException | RuntimeException e) {
+            err = e;
+            throw e;
+        } finally {
+            if (close) {
+                IOUtils.close(err, in, out);
+            }
+        }
+    }
+
+    /**
+     * @see #copy(InputStream, OutputStream, byte[], boolean)
+     */
+    public static long copy(final InputStream in, final OutputStream out, boolean close) throws IOException {
+        return copy(in, out, buffer.get(), close);
+    }
+
+    /**
+     * @see #copy(InputStream, OutputStream, byte[], boolean)
+     */
+    public static long copy(final InputStream in, final OutputStream out, byte[] buffer) throws IOException {
+        return copy(in, out, buffer, true);
+    }
+
+    /**
+     * @see #copy(InputStream, OutputStream, byte[], boolean)
+     */
+    public static long copy(final InputStream in, final OutputStream out) throws IOException {
+        return copy(in, out, buffer.get(), true);
+    }
+}
diff --git a/libs/common/src/main/java/org/opensearch/common/util/io/package-info.java b/libs/common/src/main/java/org/opensearch/common/util/io/package-info.java
new file mode 100644
index 0000000000000..5789028538a48
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/io/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common internal I/O utility classes */
+package org.opensearch.common.util.io;
diff --git a/libs/core/src/main/java/org/opensearch/core/internal/net/NetUtils.java b/libs/common/src/main/java/org/opensearch/common/util/net/NetUtils.java
similarity index 98%
rename from libs/core/src/main/java/org/opensearch/core/internal/net/NetUtils.java
rename to libs/common/src/main/java/org/opensearch/common/util/net/NetUtils.java
index 6ea3b6f953c50..708b62c290949 100644
--- a/libs/core/src/main/java/org/opensearch/core/internal/net/NetUtils.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/net/NetUtils.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.core.internal.net;
+package org.opensearch.common.util.net;
 
 import java.io.IOException;
 import java.lang.reflect.Field;
@@ -41,6 +41,8 @@
 
 /**
  * Utilities for network-related methods.
+ *
+ * @opensearch.internal
  */
 public class NetUtils {
 
diff --git a/libs/common/src/main/java/org/opensearch/common/util/net/package-info.java b/libs/common/src/main/java/org/opensearch/common/util/net/package-info.java
new file mode 100644
index 0000000000000..126b0939eab32
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/net/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common Network Utility Classes */
+package org.opensearch.common.util.net;
diff --git a/libs/common/src/main/java/org/opensearch/common/util/package-info.java b/libs/common/src/main/java/org/opensearch/common/util/package-info.java
new file mode 100644
index 0000000000000..98f786e2e82bc
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common utilities used across opensearch. */
+package org.opensearch.common.util;
diff --git a/server/src/main/java/org/opensearch/common/util/set/Sets.java b/libs/common/src/main/java/org/opensearch/common/util/set/Sets.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/util/set/Sets.java
rename to libs/common/src/main/java/org/opensearch/common/util/set/Sets.java
index 1d7175ad424b2..2dc2fb3175d27 100644
--- a/server/src/main/java/org/opensearch/common/util/set/Sets.java
+++ b/libs/common/src/main/java/org/opensearch/common/util/set/Sets.java
@@ -49,6 +49,11 @@
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
 
+/**
+ * OpenSearch sets.
+ *
+ * @opensearch.internal
+ */
 public final class Sets {
     private Sets() {}
 
@@ -114,6 +119,11 @@ public static <T> SortedSet<T> sortedDifference(Set<T> left, Set<T> right) {
         return left.stream().filter(k -> !right.contains(k)).collect(new SortedSetCollector<>());
     }
 
+    /**
+     * A sorted set collector
+     *
+     * @opensearch.internal
+     */
     private static class SortedSetCollector<T> implements Collector<T, SortedSet<T>, SortedSet<T>> {
 
         @Override
diff --git a/libs/common/src/main/java/org/opensearch/common/util/set/package-info.java b/libs/common/src/main/java/org/opensearch/common/util/set/package-info.java
new file mode 100644
index 0000000000000..298e5f53ff215
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/common/util/set/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Set collection utility package. */
+package org.opensearch.common.util.set;
diff --git a/libs/common/src/main/java/org/opensearch/package-info.java b/libs/common/src/main/java/org/opensearch/package-info.java
new file mode 100644
index 0000000000000..6a75558502c72
--- /dev/null
+++ b/libs/common/src/main/java/org/opensearch/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base opensearch package. */
+package org.opensearch;
diff --git a/libs/core/src/test/java/org/opensearch/bootstrap/JarHellTests.java b/libs/common/src/test/java/org/opensearch/bootstrap/JarHellTests.java
similarity index 96%
rename from libs/core/src/test/java/org/opensearch/bootstrap/JarHellTests.java
rename to libs/common/src/test/java/org/opensearch/bootstrap/JarHellTests.java
index d0e411ae8e3c2..d1851850e78e1 100644
--- a/libs/core/src/test/java/org/opensearch/bootstrap/JarHellTests.java
+++ b/libs/common/src/test/java/org/opensearch/bootstrap/JarHellTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.bootstrap;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.PathUtils;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
+import java.lang.Runtime.Version;
 import java.net.URL;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -156,12 +157,12 @@ public void testXmlBeansLeniency() throws Exception {
 
     public void testRequiredJDKVersionTooOld() throws Exception {
         Path dir = createTempDir();
-        List<Integer> current = JavaVersion.current().getVersion();
+        List<Integer> current = Runtime.version().version();
         List<Integer> target = new ArrayList<>(current.size());
         for (int i = 0; i < current.size(); i++) {
             target.add(current.get(i) + 1);
         }
-        JavaVersion targetVersion = JavaVersion.parse(Strings.collectionToDelimitedString(target, "."));
+        Version targetVersion = Version.parse(Strings.collectionToDelimitedString(target, "."));
 
         Manifest manifest = new Manifest();
         Attributes attributes = manifest.getMainAttributes();
@@ -173,7 +174,7 @@ public void testRequiredJDKVersionTooOld() throws Exception {
             fail("did not get expected exception");
         } catch (IllegalStateException e) {
             assertTrue(e.getMessage().contains("requires Java " + targetVersion.toString()));
-            assertTrue(e.getMessage().contains("your system: " + JavaVersion.current().toString()));
+            assertTrue(e.getMessage().contains("your system: " + Runtime.version().toString()));
         }
     }
 
@@ -209,7 +210,7 @@ public void testRequiredJDKVersionIsOK() throws Exception {
     }
 
     public void testValidVersions() {
-        String[] versions = new String[] { "1.7", "1.7.0", "0.1.7", "1.7.0.80" };
+        String[] versions = new String[] { "12-ea", "13.0.2.3-ea", "14-something", "11.0.2-21002", "11.0.14.1+1", "17.0.2+8" };
         for (String version : versions) {
             try {
                 JarHell.checkVersionFormat(version);
@@ -220,7 +221,7 @@ public void testValidVersions() {
     }
 
     public void testInvalidVersions() {
-        String[] versions = new String[] { "", "1.7.0_80", "1.7." };
+        String[] versions = new String[] { "", "1.7.0_80", "1.7.", "11.2+something-else" };
         for (String version : versions) {
             try {
                 JarHell.checkVersionFormat(version);
diff --git a/libs/core/src/test/java/org/opensearch/common/CharArraysTests.java b/libs/common/src/test/java/org/opensearch/common/CharArraysTests.java
similarity index 100%
rename from libs/core/src/test/java/org/opensearch/common/CharArraysTests.java
rename to libs/common/src/test/java/org/opensearch/common/CharArraysTests.java
diff --git a/libs/common/src/test/java/org/opensearch/common/NumbersTests.java b/libs/common/src/test/java/org/opensearch/common/NumbersTests.java
new file mode 100644
index 0000000000000..7990ba74f162a
--- /dev/null
+++ b/libs/common/src/test/java/org/opensearch/common/NumbersTests.java
@@ -0,0 +1,245 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common;
+
+import com.carrotsearch.randomizedtesting.annotations.Timeout;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class NumbersTests extends OpenSearchTestCase {
+
+    @Timeout(millis = 10000)
+    public void testToLong() {
+        assertEquals(3L, Numbers.toLong("3", false));
+        assertEquals(3L, Numbers.toLong("3.1", true));
+        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.00", false));
+        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.00", false));
+        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.00", true));
+        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.00", true));
+        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.99", true));
+        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.99", true));
+
+        assertEquals(
+            "Value [9223372036854775808] is out of range for a long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("9223372036854775808", false)).getMessage()
+        );
+        assertEquals(
+            "Value [-9223372036854775809] is out of range for a long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("-9223372036854775809", false)).getMessage()
+        );
+
+        assertEquals(
+            "Value [1e99999999] is out of range for a long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("1e99999999", false)).getMessage()
+        );
+        assertEquals(
+            "Value [-1e99999999] is out of range for a long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("-1e99999999", false)).getMessage()
+        );
+    }
+
+    public void testToLongExact() {
+        assertEquals(3L, Numbers.toLongExact(Long.valueOf(3L)));
+        assertEquals(3L, Numbers.toLongExact(Integer.valueOf(3)));
+        assertEquals(3L, Numbers.toLongExact(Short.valueOf((short) 3)));
+        assertEquals(3L, Numbers.toLongExact(Byte.valueOf((byte) 3)));
+        assertEquals(3L, Numbers.toLongExact(3d));
+        assertEquals(3L, Numbers.toLongExact(3f));
+        assertEquals(3L, Numbers.toLongExact(BigInteger.valueOf(3L)));
+        assertEquals(3L, Numbers.toLongExact(BigDecimal.valueOf(3L)));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(3.1d));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
+        assertEquals("NaN is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
+        assertEquals("Infinity is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(3.1f));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(new AtomicInteger(3))); // not supported
+        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
+    }
+
+    public void testToIntExact() {
+        assertEquals(3L, Numbers.toIntExact(Long.valueOf(3L)));
+        assertEquals(3L, Numbers.toIntExact(Integer.valueOf(3)));
+        assertEquals(3L, Numbers.toIntExact(Short.valueOf((short) 3)));
+        assertEquals(3L, Numbers.toIntExact(Byte.valueOf((byte) 3)));
+        assertEquals(3L, Numbers.toIntExact(3d));
+        assertEquals(3L, Numbers.toIntExact(3f));
+        assertEquals(3L, Numbers.toIntExact(BigInteger.valueOf(3L)));
+        assertEquals(3L, Numbers.toIntExact(BigDecimal.valueOf(3L)));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(3.1d));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
+        assertEquals("NaN is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
+        assertEquals("Infinity is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(3.1f));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toIntExact(1L << 40));
+        assertEquals("integer overflow", ae.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(new AtomicInteger(3))); // not supported
+        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
+    }
+
+    public void testToShortExact() {
+        assertEquals(3L, Numbers.toShortExact(Long.valueOf(3L)));
+        assertEquals(3L, Numbers.toShortExact(Integer.valueOf(3)));
+        assertEquals(3L, Numbers.toShortExact(Short.valueOf((short) 3)));
+        assertEquals(3L, Numbers.toShortExact(Byte.valueOf((byte) 3)));
+        assertEquals(3L, Numbers.toShortExact(3d));
+        assertEquals(3L, Numbers.toShortExact(3f));
+        assertEquals(3L, Numbers.toShortExact(BigInteger.valueOf(3L)));
+        assertEquals(3L, Numbers.toShortExact(BigDecimal.valueOf(3L)));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(3.1d));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
+        assertEquals("NaN is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
+        assertEquals("Infinity is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(3.1f));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toShortExact(100000));
+        assertEquals("short overflow: " + 100000, ae.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(new AtomicInteger(3))); // not supported
+        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
+    }
+
+    public void testToByteExact() {
+        assertEquals(3L, Numbers.toByteExact(Long.valueOf(3L)));
+        assertEquals(3L, Numbers.toByteExact(Integer.valueOf(3)));
+        assertEquals(3L, Numbers.toByteExact(Short.valueOf((short) 3)));
+        assertEquals(3L, Numbers.toByteExact(Byte.valueOf((byte) 3)));
+        assertEquals(3L, Numbers.toByteExact(3d));
+        assertEquals(3L, Numbers.toByteExact(3f));
+        assertEquals(3L, Numbers.toByteExact(BigInteger.valueOf(3L)));
+        assertEquals(3L, Numbers.toByteExact(BigDecimal.valueOf(3L)));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(3.1d));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
+        assertEquals("NaN is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
+        assertEquals("Infinity is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(3.1f));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toByteExact(300));
+        assertEquals("byte overflow: " + 300, ae.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(new AtomicInteger(3))); // not supported
+        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
+    }
+
+    public void testToUnsignedLong() {
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLong("3", false));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLong("3.1", true));
+        assertEquals(new BigInteger("17223372036854775807"), Numbers.toUnsignedLong("17223372036854775807.00", false));
+        assertEquals(new BigInteger("17223372036854775807"), Numbers.toUnsignedLong("17223372036854775807.00", true));
+        assertEquals(new BigInteger("17223372036854775807"), Numbers.toUnsignedLong("17223372036854775807.99", true));
+        assertEquals(new BigInteger("18446744073709551000"), Numbers.toUnsignedLong("1.8446744073709551E19", true));
+
+        assertEquals(
+            "Value [19223372036854775808] is out of range for an unsigned long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLong("19223372036854775808", false)).getMessage()
+        );
+        assertEquals(
+            "Value [-1] is out of range for an unsigned long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLong("-1", false)).getMessage()
+        );
+
+        assertEquals(
+            "Value [1.8446744073709552E19] is out of range for an unsigned long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLong("1.8446744073709552E19", false)).getMessage()
+        );
+
+        assertEquals(
+            "Value [1e99999999] is out of range for an unsigned long",
+            expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLong("1e99999999", false)).getMessage()
+        );
+    }
+
+    public void testToUnsignedLongExact() {
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(Long.valueOf(3L)));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(Integer.valueOf(3)));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(Short.valueOf((short) 3)));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(Byte.valueOf((byte) 3)));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(3d));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(3f));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(BigInteger.valueOf(3L)));
+        assertEquals(BigInteger.valueOf(3L), Numbers.toUnsignedLongExact(BigDecimal.valueOf(3L)));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLongExact(3.1d));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLongExact(Double.NaN));
+        assertEquals("NaN is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLongExact(Double.POSITIVE_INFINITY));
+        assertEquals("Infinity is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLongExact(3.1f));
+        assertEquals("3.1 is not an integer value", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toUnsignedLongExact(new AtomicInteger(3))); // not supported
+        assertEquals("Cannot convert [3] of class [java.util.concurrent.atomic.AtomicInteger] to a BigInteger", e.getMessage());
+    }
+
+    public void testToUnsignedBigInteger() {
+        final BigInteger random = randomUnsignedLong();
+        assertEquals(random, Numbers.toUnsignedBigInteger(random.longValue()));
+        assertEquals(Numbers.MAX_UNSIGNED_LONG_VALUE, Numbers.toUnsignedBigInteger(Numbers.MAX_UNSIGNED_LONG_VALUE.longValue()));
+    }
+
+    public void testNextPowerOfTwo() {
+        // Negative values:
+        for (int i = 0; i < 1000; i++) {
+            long value = randomLongBetween(-500000, -1);
+            assertEquals(1, Numbers.nextPowerOfTwo(value));
+        }
+
+        // Zero value:
+        assertEquals(1, Numbers.nextPowerOfTwo(0L));
+
+        // Positive values:
+        for (int i = 0; i < 1000; i++) {
+            long value = randomLongBetween(1, 500000);
+            long nextPowerOfTwo = Numbers.nextPowerOfTwo(value);
+
+            assertTrue(nextPowerOfTwo > value); // must be strictly greater
+            assertTrue((nextPowerOfTwo >>> 1) <= value); // must be greater by no more than one power of two
+            assertEquals(0, nextPowerOfTwo & (nextPowerOfTwo - 1)); // must be a power of two
+        }
+    }
+}
diff --git a/libs/common/src/test/java/org/opensearch/common/SetOnceTests.java b/libs/common/src/test/java/org/opensearch/common/SetOnceTests.java
new file mode 100644
index 0000000000000..0392ff62dd115
--- /dev/null
+++ b/libs/common/src/test/java/org/opensearch/common/SetOnceTests.java
@@ -0,0 +1,120 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common;
+
+import org.opensearch.common.SetOnce.AlreadySetException;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Random;
+
+import static org.hamcrest.CoreMatchers.containsString;
+
+public class SetOnceTests extends OpenSearchTestCase {
+    private static final class SetOnceThread extends Thread {
+        SetOnce<Integer> set;
+        boolean success = false;
+        final Random RAND;
+
+        public SetOnceThread(Random random) {
+            RAND = new Random(random.nextLong());
+        }
+
+        @Override
+        public void run() {
+            try {
+                sleep(RAND.nextInt(10)); // sleep for a short time
+                set.set(Integer.valueOf(getName().substring(2)));
+                success = true;
+            } catch (@SuppressWarnings("unused") InterruptedException e) {
+                // ignore
+            } catch (@SuppressWarnings("unused") RuntimeException e) {
+                // TODO: change exception type
+                // expected.
+                success = false;
+            }
+        }
+    }
+
+    public void testEmptyCtor() {
+        SetOnce<Integer> set = new SetOnce<>();
+        assertNull(set.get());
+    }
+
+    public void testSettingCtor() {
+        SetOnce<Integer> set = new SetOnce<>(5);
+        assertEquals(5, set.get().intValue());
+
+        AlreadySetException alreadySetException = expectThrows(AlreadySetException.class, () -> set.set(7));
+        assertThat(alreadySetException.getMessage(), containsString("The object cannot be set twice!"));
+    }
+
+    public void testSetOnce() {
+        SetOnce<Integer> set = new SetOnce<>();
+        set.set(5);
+        assertEquals(5, set.get().intValue());
+
+        AlreadySetException alreadySetException = expectThrows(AlreadySetException.class, () -> set.set(7));
+        assertThat(alreadySetException.getMessage(), containsString("The object cannot be set twice!"));
+    }
+
+    public void testTrySet() {
+        SetOnce<Integer> set = new SetOnce<>();
+        assertTrue(set.trySet(5));
+        assertEquals(5, set.get().intValue());
+        assertFalse(set.trySet(7));
+        assertEquals(5, set.get().intValue());
+    }
+
+    public void testSetMultiThreaded() throws Exception {
+        final SetOnce<Integer> set = new SetOnce<>();
+        SetOnceThread[] threads = new SetOnceThread[10];
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new SetOnceThread(random());
+            threads[i].setName("t-" + (i + 1));
+            threads[i].set = set;
+        }
+
+        for (Thread t : threads) {
+            t.start();
+        }
+
+        for (Thread t : threads) {
+            t.join();
+        }
+
+        for (SetOnceThread t : threads) {
+            if (t.success) {
+                int expectedVal = Integer.parseInt(t.getName().substring(2));
+                assertEquals("thread " + t.getName(), expectedVal, t.set.get().intValue());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/collect/IteratorsTests.java b/libs/common/src/test/java/org/opensearch/common/collect/IteratorsTests.java
similarity index 98%
rename from server/src/test/java/org/opensearch/common/collect/IteratorsTests.java
rename to libs/common/src/test/java/org/opensearch/common/collect/IteratorsTests.java
index 155391aaaf62f..1ad6751014073 100644
--- a/server/src/test/java/org/opensearch/common/collect/IteratorsTests.java
+++ b/libs/common/src/test/java/org/opensearch/common/collect/IteratorsTests.java
@@ -83,6 +83,7 @@ public void testRandomSingleton() {
         int numberOfIterators = randomIntBetween(1, 1000);
         int singletonIndex = randomIntBetween(0, numberOfIterators - 1);
         int value = randomInt();
+        @SuppressWarnings("rawtypes")
         Iterator<Integer>[] iterators = new Iterator[numberOfIterators];
         for (int i = 0; i < numberOfIterators; i++) {
             iterators[i] = i != singletonIndex ? empty() : singletonIterator(value);
@@ -92,6 +93,7 @@ public void testRandomSingleton() {
 
     public void testRandomIterators() {
         int numberOfIterators = randomIntBetween(1, 1000);
+        @SuppressWarnings("rawtypes")
         Iterator<Integer>[] iterators = new Iterator[numberOfIterators];
         List<Integer> values = new ArrayList<>();
         for (int i = 0; i < numberOfIterators; i++) {
diff --git a/libs/core/src/test/java/org/opensearch/common/collect/TupleTests.java b/libs/common/src/test/java/org/opensearch/common/collect/TupleTests.java
similarity index 100%
rename from libs/core/src/test/java/org/opensearch/common/collect/TupleTests.java
rename to libs/common/src/test/java/org/opensearch/common/collect/TupleTests.java
diff --git a/libs/common/src/test/java/org/opensearch/common/hash/T1Ha1Tests.java b/libs/common/src/test/java/org/opensearch/common/hash/T1Ha1Tests.java
new file mode 100644
index 0000000000000..e348fbf759bdd
--- /dev/null
+++ b/libs/common/src/test/java/org/opensearch/common/hash/T1Ha1Tests.java
@@ -0,0 +1,312 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.invoke.VarHandle;
+import java.nio.ByteOrder;
+
+public class T1Ha1Tests extends HashFunctionTestCase {
+    private static final VarHandle LONG_HANDLE = MethodHandles.byteArrayViewVarHandle(long[].class, ByteOrder.LITTLE_ENDIAN);
+    private final byte[] scratch = new byte[8];
+
+    /**
+     * Inspired from the tests defined in the reference implementation:
+     * <a href="https://github.com/erthink/t1ha/blob/master/src/t1ha_selfcheck.c">t1ha_selfcheck.c</a>
+     */
+    public void testSelfCheck() {
+        byte[] testPattern = {
+            0,
+            1,
+            2,
+            3,
+            4,
+            5,
+            6,
+            7,
+            (byte) 0xFF,
+            0x7F,
+            0x3F,
+            0x1F,
+            0xF,
+            8,
+            16,
+            32,
+            64,
+            (byte) 0x80,
+            (byte) 0xFE,
+            (byte) 0xFC,
+            (byte) 0xF8,
+            (byte) 0xF0,
+            (byte) 0xE0,
+            (byte) 0xC0,
+            (byte) 0xFD,
+            (byte) 0xFB,
+            (byte) 0xF7,
+            (byte) 0xEF,
+            (byte) 0xDF,
+            (byte) 0xBF,
+            0x55,
+            (byte) 0xAA,
+            11,
+            17,
+            19,
+            23,
+            29,
+            37,
+            42,
+            43,
+            'a',
+            'b',
+            'c',
+            'd',
+            'e',
+            'f',
+            'g',
+            'h',
+            'i',
+            'j',
+            'k',
+            'l',
+            'm',
+            'n',
+            'o',
+            'p',
+            'q',
+            'r',
+            's',
+            't',
+            'u',
+            'v',
+            'w',
+            'x' };
+
+        // Reference hashes when using {@link Math::unsignedMultiplyHigh} in the mux64 step.
+        // These values match the ones defined in the reference implementation:
+        // https://github.com/erthink/t1ha/blob/master/src/t1ha1_selfcheck.c#L51-L72
+        long[] referenceUnsignedMultiplyHigh = {
+            0L,
+            0x6A580668D6048674L,
+            0xA2FE904AFF0D0879L,
+            0xE3AB9C06FAF4D023L,
+            0x6AF1C60874C95442L,
+            0xB3557E561A6C5D82L,
+            0x0AE73C696F3D37C0L,
+            0x5EF25F7062324941L,
+            0x9B784F3B4CE6AF33L,
+            0x6993BB206A74F070L,
+            0xF1E95DF109076C4CL,
+            0x4E1EB70C58E48540L,
+            0x5FDD7649D8EC44E4L,
+            0x559122C706343421L,
+            0x380133D58665E93DL,
+            0x9CE74296C8C55AE4L,
+            0x3556F9A5757AB6D0L,
+            0xF62751F7F25C469EL,
+            0x851EEC67F6516D94L,
+            0xED463EE3848A8695L,
+            0xDC8791FEFF8ED3ACL,
+            0x2569C744E1A282CFL,
+            0xF90EB7C1D70A80B9L,
+            0x68DFA6A1B8050A4CL,
+            0x94CCA5E8210D2134L,
+            0xF5CC0BEABC259F52L,
+            0x40DBC1F51618FDA7L,
+            0x0807945BF0FB52C6L,
+            0xE5EF7E09DE70848DL,
+            0x63E1DF35FEBE994AL,
+            0x2025E73769720D5AL,
+            0xAD6120B2B8A152E1L,
+            0x2A71D9F13959F2B7L,
+            0x8A20849A27C32548L,
+            0x0BCBC9FE3B57884EL,
+            0x0E028D255667AEADL,
+            0xBE66DAD3043AB694L,
+            0xB00E4C1238F9E2D4L,
+            0x5C54BDE5AE280E82L,
+            0x0E22B86754BC3BC4L,
+            0x016707EBF858B84DL,
+            0x990015FBC9E095EEL,
+            0x8B9AF0A3E71F042FL,
+            0x6AA56E88BD380564L,
+            0xAACE57113E681A0FL,
+            0x19F81514AFA9A22DL,
+            0x80DABA3D62BEAC79L,
+            0x715210412CABBF46L,
+            0xD8FA0B9E9D6AA93FL,
+            0x6C2FC5A4109FD3A2L,
+            0x5B3E60EEB51DDCD8L,
+            0x0A7C717017756FE7L,
+            0xA73773805CA31934L,
+            0x4DBD6BB7A31E85FDL,
+            0x24F619D3D5BC2DB4L,
+            0x3E4AF35A1678D636L,
+            0x84A1A8DF8D609239L,
+            0x359C862CD3BE4FCDL,
+            0xCF3A39F5C27DC125L,
+            0xC0FF62F8FD5F4C77L,
+            0x5E9F2493DDAA166CL,
+            0x17424152BE1CA266L,
+            0xA78AFA5AB4BBE0CDL,
+            0x7BFB2E2CEF118346L,
+            0x647C3E0FF3E3D241L,
+            0x0352E4055C13242EL,
+            0x6F42FC70EB660E38L,
+            0x0BEBAD4FABF523BAL,
+            0x9269F4214414D61DL,
+            0x1CA8760277E6006CL,
+            0x7BAD25A859D87B5DL,
+            0xAD645ADCF7414F1DL,
+            0xB07F517E88D7AFB3L,
+            0xB321C06FB5FFAB5CL,
+            0xD50F162A1EFDD844L,
+            0x1DFD3D1924FBE319L,
+            0xDFAEAB2F09EF7E78L,
+            0xA7603B5AF07A0B1EL,
+            0x41CD044C0E5A4EE3L,
+            0xF64D2F86E813BF33L,
+            0xFF9FDB99305EB06AL };
+
+        // Reference hashes when using {@link Math::multiplyHigh} in the mux64 step.
+        long[] referenceMultiplyHigh = {
+            0L,
+            0xCE510B7405E0A2CAL,
+            0xC0A2DA74A8271FCBL,
+            0x1C549C06FAF4D023L,
+            0x084CDA0ED41CD2D4L,
+            0xD05BA7AA9FEECE5BL,
+            0x7D6128AB2CCC4EB1L,
+            0x62332FA6EC1B50AAL,
+            0x1B66C81767870EF2L,
+            0xEC6B92A37AED73B8L,
+            0x1712987232EF4ED3L,
+            0xAA503A04AE2450B5L,
+            0x15D25DE445730A6CL,
+            0xAB87E38AA8D21746L,
+            0x18CAE735BBF62D15L,
+            0x0D56DFF9914CA656L,
+            0xCB4F5859A9AE5B52L,
+            0xEE97003F7B1283E1L,
+            0x50CFB2AF0F54BA6DL,
+            0x570B4D6AE4C67814L,
+            0x1ED59274A97497EBL,
+            0x8608D03D165C59BFL,
+            0x6CBE0E537BE04C02L,
+            0xD4C8FCFD4179A874L,
+            0xFB4E677D876118A1L,
+            0x6B1A96F1B4765D79L,
+            0x1075B9B89BDFE5F8L,
+            0x02771D08F2891CB1L,
+            0x4BB8E16FF410F19EL,
+            0x3EB7849C0DFAF566L,
+            0x173B09359DE422CFL,
+            0xFE212C6DB7474306L,
+            0xA74E7C2D632664EFL,
+            0x56ECDED6546F0914L,
+            0x08DEF866EF20A94BL,
+            0x7D0BAC64606521F1L,
+            0xCA6BA9817A357FA9L,
+            0x0873B834A6E2AAE4L,
+            0x45EE02D6DCF8992EL,
+            0x3EA060225B3E1C1FL,
+            0x24DBB6D02D5CC531L,
+            0xE5E91A7340BF9382L,
+            0x28975F86E2E2177FL,
+            0x80E48374A6B42E85L,
+            0xDF40392265BB4A66L,
+            0x43750475A48C7023L,
+            0x5648BD3E391C01D3L,
+            0x9BE9E11AD1A6C369L,
+            0x2E079CB8C1A11F50L,
+            0xB2D538403F1020F1L,
+            0x297518A4EF6AF5F1L,
+            0xA8CE1B90167A6F8BL,
+            0xB926B2FA50541BA9L,
+            0xC46A2D3BD6925A35L,
+            0x3071BC8E6C400487L,
+            0x300D3885894BA47FL,
+            0x840BFF3BEB7EEADDL,
+            0xDC9E04DF744BDC0CL,
+            0xBE01CF6841412C77L,
+            0x6C55B2DC74B816A1L,
+            0x4D4C63128A344F82L,
+            0xC6227497E100B463L,
+            0x53C9987705EA71C0L,
+            0x3E355394668C3559L,
+            0x05984B7D358B107AL,
+            0x4D32FA1D79002A57L,
+            0x910B0DAD1440EC24L,
+            0x025BDE6A7BEBF320L,
+            0x0D33817EF345D999L,
+            0xBA0DE64B3F4DB34AL,
+            0x54666461D0EB4FD7L,
+            0x746ECFA92D1CAF81L,
+            0x6E6A774ACD266DF2L,
+            0x1A86161AE8E82A85L,
+            0xFFF7C351A4CEC13DL,
+            0xFFF05844F57498B8L,
+            0x8DB71789127C6C13L,
+            0x4A52ACF805F370ABL,
+            0xFE13F90A1ACFBD58L,
+            0x615730E301ED12E2L,
+            0x1A2D4AA43B6C0103L };
+
+        long[] reference = hasUnsignedMultiplyHigh() ? referenceUnsignedMultiplyHigh : referenceMultiplyHigh;
+
+        int offset = 0;
+        assertEquals(reference[offset++], T1ha1.hash(null, 0, 0, 0L)); // empty-zero
+        assertEquals(reference[offset++], T1ha1.hash(null, 0, 0, ~0L)); // empty-all1
+        assertEquals(reference[offset++], T1ha1.hash(testPattern, 0, 64, 0L)); // bin64-zero
+
+        long seed = 1;
+        for (int i = 1; i < 64; i++) {
+            assertEquals(reference[offset++], T1ha1.hash(testPattern, 0, i, seed)); // bin%i-1p%i
+            seed <<= 1;
+        }
+
+        seed = ~0L;
+        for (int i = 1; i <= 7; i++) {
+            seed <<= 1;
+            assertEquals(reference[offset++], T1ha1.hash(testPattern, i, 64 - i, seed)); // align%i_F%i
+        }
+
+        byte[] testPatternLong = new byte[512];
+        for (int i = 0; i < testPatternLong.length; i++) {
+            testPatternLong[i] = (byte) i;
+        }
+        for (int i = 0; i <= 7; i++) {
+            assertEquals(reference[offset++], T1ha1.hash(testPatternLong, i, 128 + i * 17, seed)); // long-%05i
+        }
+    }
+
+    @Override
+    public byte[] hash(byte[] input) {
+        long hash = T1ha1.hash(input, 0, input.length);
+        LONG_HANDLE.set(scratch, 0, hash);
+        return scratch;
+    }
+
+    @Override
+    public int outputBits() {
+        return 64;
+    }
+
+    private static boolean hasUnsignedMultiplyHigh() {
+        try {
+            MethodHandles.publicLookup()
+                .findStatic(Math.class, "unsignedMultiplyHigh", MethodType.methodType(long.class, long.class, long.class));
+            return true;
+        } catch (NoSuchMethodException e) {
+            return false;
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/network/CidrsTests.java b/libs/common/src/test/java/org/opensearch/common/network/CidrsTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/network/CidrsTests.java
rename to libs/common/src/test/java/org/opensearch/common/network/CidrsTests.java
diff --git a/server/src/test/java/org/opensearch/common/network/InetAddressesTests.java b/libs/common/src/test/java/org/opensearch/common/network/InetAddressesTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/network/InetAddressesTests.java
rename to libs/common/src/test/java/org/opensearch/common/network/InetAddressesTests.java
diff --git a/server/src/test/java/org/opensearch/common/network/NetworkAddressTests.java b/libs/common/src/test/java/org/opensearch/common/network/NetworkAddressTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/network/NetworkAddressTests.java
rename to libs/common/src/test/java/org/opensearch/common/network/NetworkAddressTests.java
diff --git a/server/src/test/java/org/opensearch/common/recycler/AbstractRecyclerTestCase.java b/libs/common/src/test/java/org/opensearch/common/recycler/AbstractRecyclerTestCase.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/recycler/AbstractRecyclerTestCase.java
rename to libs/common/src/test/java/org/opensearch/common/recycler/AbstractRecyclerTestCase.java
diff --git a/server/src/test/java/org/opensearch/common/recycler/ConcurrentRecyclerTests.java b/libs/common/src/test/java/org/opensearch/common/recycler/ConcurrentRecyclerTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/recycler/ConcurrentRecyclerTests.java
rename to libs/common/src/test/java/org/opensearch/common/recycler/ConcurrentRecyclerTests.java
diff --git a/server/src/test/java/org/opensearch/common/recycler/LockedRecyclerTests.java b/libs/common/src/test/java/org/opensearch/common/recycler/LockedRecyclerTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/recycler/LockedRecyclerTests.java
rename to libs/common/src/test/java/org/opensearch/common/recycler/LockedRecyclerTests.java
diff --git a/server/src/test/java/org/opensearch/common/recycler/NoneRecyclerTests.java b/libs/common/src/test/java/org/opensearch/common/recycler/NoneRecyclerTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/recycler/NoneRecyclerTests.java
rename to libs/common/src/test/java/org/opensearch/common/recycler/NoneRecyclerTests.java
diff --git a/server/src/test/java/org/opensearch/common/recycler/QueueRecyclerTests.java b/libs/common/src/test/java/org/opensearch/common/recycler/QueueRecyclerTests.java
similarity index 100%
rename from server/src/test/java/org/opensearch/common/recycler/QueueRecyclerTests.java
rename to libs/common/src/test/java/org/opensearch/common/recycler/QueueRecyclerTests.java
diff --git a/libs/core/src/test/java/org/opensearch/common/unit/TimeValueTests.java b/libs/common/src/test/java/org/opensearch/common/unit/TimeValueTests.java
similarity index 100%
rename from libs/core/src/test/java/org/opensearch/common/unit/TimeValueTests.java
rename to libs/common/src/test/java/org/opensearch/common/unit/TimeValueTests.java
diff --git a/libs/core/src/test/java/org/opensearch/common/util/OpenSearchSloppyMathTests.java b/libs/common/src/test/java/org/opensearch/common/util/OpenSearchSloppyMathTests.java
similarity index 100%
rename from libs/core/src/test/java/org/opensearch/common/util/OpenSearchSloppyMathTests.java
rename to libs/common/src/test/java/org/opensearch/common/util/OpenSearchSloppyMathTests.java
diff --git a/libs/core/src/test/java/org/opensearch/common/util/concurrent/RefCountedTests.java b/libs/common/src/test/java/org/opensearch/common/util/concurrent/RefCountedTests.java
similarity index 100%
rename from libs/core/src/test/java/org/opensearch/common/util/concurrent/RefCountedTests.java
rename to libs/common/src/test/java/org/opensearch/common/util/concurrent/RefCountedTests.java
diff --git a/libs/core/src/test/resources/org/opensearch/bootstrap/duplicate-classes.jar b/libs/common/src/test/resources/org/opensearch/bootstrap/duplicate-classes.jar
similarity index 100%
rename from libs/core/src/test/resources/org/opensearch/bootstrap/duplicate-classes.jar
rename to libs/common/src/test/resources/org/opensearch/bootstrap/duplicate-classes.jar
diff --git a/libs/core/src/test/resources/org/opensearch/bootstrap/duplicate-xmlbeans-classes.jar b/libs/common/src/test/resources/org/opensearch/bootstrap/duplicate-xmlbeans-classes.jar
similarity index 100%
rename from libs/core/src/test/resources/org/opensearch/bootstrap/duplicate-xmlbeans-classes.jar
rename to libs/common/src/test/resources/org/opensearch/bootstrap/duplicate-xmlbeans-classes.jar
diff --git a/libs/compress/build.gradle b/libs/compress/build.gradle
new file mode 100644
index 0000000000000..7a5bc2f573dea
--- /dev/null
+++ b/libs/compress/build.gradle
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+apply plugin: 'opensearch.build'
+apply plugin: 'opensearch.publish'
+
+base {
+  archivesName = 'opensearch-compress'
+}
+
+dependencies {
+  api project(':libs:opensearch-common')
+  api project(':libs:opensearch-core')
+
+  //zstd
+  api "com.github.luben:zstd-jni:${versions.zstd}"
+
+  testImplementation(project(":test:framework")) {
+    // tests use the locally compiled version of server
+    exclude group: 'org.opensearch', module: 'opensearch-compress'
+  }
+}
+
+tasks.named('forbiddenApisMain').configure {
+  // :libs:opensearch-compress does not depend on server
+  // TODO: Need to decide how we want to handle for forbidden signatures with the changes to server
+  replaceSignatureFiles 'jdk-signatures'
+}
+
+jarHell.enabled = false
diff --git a/libs/compress/licenses/zstd-jni-1.5.5-5.jar.sha1 b/libs/compress/licenses/zstd-jni-1.5.5-5.jar.sha1
new file mode 100644
index 0000000000000..498c60c34e3da
--- /dev/null
+++ b/libs/compress/licenses/zstd-jni-1.5.5-5.jar.sha1
@@ -0,0 +1 @@
+74ffdc5f140080adacf5278287aadd950179f848
\ No newline at end of file
diff --git a/libs/compress/licenses/zstd-jni-LICENSE.txt b/libs/compress/licenses/zstd-jni-LICENSE.txt
new file mode 100644
index 0000000000000..c4dd507c1c72f
--- /dev/null
+++ b/libs/compress/licenses/zstd-jni-LICENSE.txt
@@ -0,0 +1,29 @@
+-----------------------------------------------------------------------------
+** Beginning of "BSD License" text. **
+
+Zstd-jni: JNI bindings to Zstd Library
+
+Copyright (c) 2015-present, Luben Karavelov/ All rights reserved.
+
+BSD License
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this
+  list of conditions and the following disclaimer in the documentation and/or
+  other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/libs/compress/licenses/zstd-jni-NOTICE.txt b/libs/compress/licenses/zstd-jni-NOTICE.txt
new file mode 100644
index 0000000000000..389c97cbc892d
--- /dev/null
+++ b/libs/compress/licenses/zstd-jni-NOTICE.txt
@@ -0,0 +1 @@
+The code for the JNI bindings to Zstd library was originally authored by Luben Karavelov
diff --git a/libs/compress/src/main/java/org/opensearch/compress/ZstdCompressor.java b/libs/compress/src/main/java/org/opensearch/compress/ZstdCompressor.java
new file mode 100644
index 0000000000000..e2a740f72be93
--- /dev/null
+++ b/libs/compress/src/main/java/org/opensearch/compress/ZstdCompressor.java
@@ -0,0 +1,136 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.compress;
+
+import com.github.luben.zstd.RecyclingBufferPool;
+import com.github.luben.zstd.ZstdInputStreamNoFinalizer;
+import com.github.luben.zstd.ZstdOutputStreamNoFinalizer;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Arrays;
+
+/**
+ * {@link Compressor} implementation based on the ZSTD compression algorithm.
+ *
+ * @opensearch.api - registered name requires BWC support
+ * @opensearch.experimental - class methods might change
+ */
+public class ZstdCompressor implements Compressor {
+
+    /**
+     * An arbitrary header that we use to identify compressed streams
+     * It needs to be different from other compressors and to not be specific
+     * enough so that no stream starting with these bytes could be detected as
+     * a XContent
+     * */
+    private static final byte[] HEADER = new byte[] { 'Z', 'S', 'T', 'D', '\0' };
+
+    /**
+     * The name to register the compressor by
+     *
+     * @opensearch.api - requires BWC support
+     */
+    @PublicApi(since = "2.10.0")
+    public static final String NAME = "ZSTD";
+
+    /**
+     * The compression level for {@link ZstdOutputStreamNoFinalizer}
+     */
+    private static final int LEVEL = 3;
+
+    /** The buffer size for {@link BufferedInputStream} and {@link BufferedOutputStream}
+     */
+    private static final int BUFFER_SIZE = 4096;
+
+    /**
+     * Compares the given bytes with the {@link ZstdCompressor#HEADER} of a compressed stream
+     * @param bytes the bytes to compare to ({@link ZstdCompressor#HEADER})
+     * @return true if the bytes are the {@link ZstdCompressor#HEADER}, false otherwise
+     */
+    @Override
+    public boolean isCompressed(BytesReference bytes) {
+        if (bytes.length() < HEADER.length) {
+            return false;
+        }
+        for (int i = 0; i < HEADER.length; ++i) {
+            if (bytes.get(i) != HEADER[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Returns the length of the {@link ZstdCompressor#HEADER}
+     * @return the {@link ZstdCompressor#HEADER} length
+     */
+    @Override
+    public int headerLength() {
+        return HEADER.length;
+    }
+
+    /**
+     * Returns a new {@link ZstdInputStreamNoFinalizer} from the given compressed {@link InputStream}
+     * @param in the compressed {@link InputStream}
+     * @return a new {@link ZstdInputStreamNoFinalizer} from the given compressed {@link InputStream}
+     * @throws IOException if an I/O error occurs
+     * @throws IllegalArgumentException if the input stream is not compressed with ZSTD
+     */
+    @Override
+    public InputStream threadLocalInputStream(InputStream in) throws IOException {
+        final byte[] header = in.readNBytes(HEADER.length);
+        if (Arrays.equals(header, HEADER) == false) {
+            throw new IllegalArgumentException("Input stream is not compressed with ZSTD!");
+        }
+        return new ZstdInputStreamNoFinalizer(new BufferedInputStream(in, BUFFER_SIZE), RecyclingBufferPool.INSTANCE);
+    }
+
+    /**
+     * Returns a new {@link ZstdOutputStreamNoFinalizer} from the given {@link OutputStream}
+     * @param out the {@link OutputStream}
+     * @return a new {@link ZstdOutputStreamNoFinalizer} from the given {@link OutputStream}
+     * @throws IOException if an I/O error occurs
+     */
+    @Override
+    public OutputStream threadLocalOutputStream(OutputStream out) throws IOException {
+        out.write(HEADER);
+        return new ZstdOutputStreamNoFinalizer(new BufferedOutputStream(out, BUFFER_SIZE), RecyclingBufferPool.INSTANCE, LEVEL);
+    }
+
+    /**
+     * Always throws an {@link UnsupportedOperationException} as ZSTD compression is supported only for snapshotting
+     * @param bytesReference a reference to the bytes to uncompress
+     * @return always throws an exception
+     * @throws UnsupportedOperationException if the method is called
+     * @throws IOException is never thrown
+     */
+    @Override
+    public BytesReference uncompress(BytesReference bytesReference) throws IOException {
+        throw new UnsupportedOperationException("ZSTD compression is supported only for snapshotting");
+    }
+
+    /**
+     * Always throws an {@link UnsupportedOperationException} as ZSTD compression is supported only for snapshotting
+     * @param bytesReference a reference to the bytes to compress
+     * @return always throws an exception
+     * @throws UnsupportedOperationException if the method is called
+     */
+    @Override
+    public BytesReference compress(BytesReference bytesReference) throws IOException {
+        throw new UnsupportedOperationException("ZSTD compression is supported only for snapshotting");
+    }
+}
diff --git a/libs/compress/src/main/java/org/opensearch/compress/package-info.java b/libs/compress/src/main/java/org/opensearch/compress/package-info.java
new file mode 100644
index 0000000000000..3ffa53079fa69
--- /dev/null
+++ b/libs/compress/src/main/java/org/opensearch/compress/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Concrete {@link org.opensearch.core.compress.Compressor} implementations
+ */
+package org.opensearch.compress;
diff --git a/libs/compress/src/main/java/org/opensearch/compress/spi/CompressionProvider.java b/libs/compress/src/main/java/org/opensearch/compress/spi/CompressionProvider.java
new file mode 100644
index 0000000000000..f0c6969377d78
--- /dev/null
+++ b/libs/compress/src/main/java/org/opensearch/compress/spi/CompressionProvider.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.compress.spi;
+
+import org.opensearch.compress.ZstdCompressor;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.spi.CompressorProvider;
+
+import java.util.AbstractMap.SimpleEntry;
+import java.util.List;
+import java.util.Map.Entry;
+
+/**
+ * Additional "optional" compressor implementations provided by the opensearch compress library
+ *
+ * @opensearch.internal
+ */
+public class CompressionProvider implements CompressorProvider {
+
+    /**
+     * Returns the concrete {@link Compressor}s provided by the compress library
+     * @return a list of {@link Compressor}s
+     * */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @Override
+    public List<Entry<String, Compressor>> getCompressors() {
+        return List.of(new SimpleEntry<>(ZstdCompressor.NAME, new ZstdCompressor()));
+    }
+}
diff --git a/libs/compress/src/main/java/org/opensearch/compress/spi/package-info.java b/libs/compress/src/main/java/org/opensearch/compress/spi/package-info.java
new file mode 100644
index 0000000000000..47d982a7ca2f9
--- /dev/null
+++ b/libs/compress/src/main/java/org/opensearch/compress/spi/package-info.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Service Provider Interface for registering concrete {@link org.opensearch.core.compress.Compressor}
+ * implementations.
+ *
+ * See {@link org.opensearch.compress.ZstdCompressor}
+ */
+package org.opensearch.compress.spi;
diff --git a/libs/compress/src/main/java/org/opensearch/package-info.java b/libs/compress/src/main/java/org/opensearch/package-info.java
new file mode 100644
index 0000000000000..264680e9cb271
--- /dev/null
+++ b/libs/compress/src/main/java/org/opensearch/package-info.java
@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This is the compress library for registering optional
+ * {@link org.opensearch.core.compress.Compressor} implementations
+ */
+package org.opensearch;
diff --git a/libs/compress/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider b/libs/compress/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
new file mode 100644
index 0000000000000..a9ea063e24436
--- /dev/null
+++ b/libs/compress/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
@@ -0,0 +1,9 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+
+org.opensearch.compress.spi.CompressionProvider
diff --git a/libs/compress/src/test/java/org/opensearch/compress/ZstdCompressTests.java b/libs/compress/src/test/java/org/opensearch/compress/ZstdCompressTests.java
new file mode 100644
index 0000000000000..54864054a0e02
--- /dev/null
+++ b/libs/compress/src/test/java/org/opensearch/compress/ZstdCompressTests.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.compress;
+
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.test.core.compress.AbstractCompressorTestCase;
+
+/**
+ * Test streaming compression
+ */
+public class ZstdCompressTests extends AbstractCompressorTestCase {
+
+    private final Compressor compressor = new ZstdCompressor();
+
+    @Override
+    protected Compressor compressor() {
+        return compressor;
+    }
+}
diff --git a/libs/core/.classpath1 b/libs/core/.classpath1
index 3a20aa700e9e9..3586b0ee921fb 100644
--- a/libs/core/.classpath1
+++ b/libs/core/.classpath1
@@ -253,12 +253,6 @@
 			<attribute name="test" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry sourcepath="/home/alpar/.gradle/caches/modules-2/files-2.1/com.carrotsearch/hppc/0.8.1/b338e50c3f98c7ec2bf67a5efb7fa8726a4a9b2d/hppc-0.8.1-sources.jar" kind="lib" path="/home/alpar/.gradle/caches/modules-2/files-2.1/com.carrotsearch/hppc/0.8.1/ffc7ba8f289428b9508ab484b8001dea944ae603/hppc-0.8.1.jar">
-		<attributes>
-			<attribute name="gradle_used_by_scope" value="test"/>
-			<attribute name="test" value="true"/>
-		</attributes>
-	</classpathentry>
 	<classpathentry sourcepath="/home/alpar/.gradle/caches/modules-2/files-2.1/joda-time/joda-time/2.10.2/fbf6cbd712c30629c77cefa42fe15ca888e609d5/joda-time-2.10.2-sources.jar" kind="lib" path="/home/alpar/.gradle/caches/modules-2/files-2.1/joda-time/joda-time/2.10.2/a079fc39ccc3de02acdeb7117443e5d9bd431687/joda-time-2.10.2.jar">
 		<attributes>
 			<attribute name="gradle_used_by_scope" value="test"/>
diff --git a/libs/core/build.gradle b/libs/core/build.gradle
index 374f2fe572a12..1ab2073759788 100644
--- a/libs/core/build.gradle
+++ b/libs/core/build.gradle
@@ -30,10 +30,11 @@
 
 import org.opensearch.gradle.info.BuildParams
 
-apply plugin: 'nebula.optional-base'
 apply plugin: 'opensearch.publish'
 
-archivesBaseName = 'opensearch-core'
+base {
+  archivesBaseName = 'opensearch-core'
+}
 
 // we want to keep the JDKs in our IDEs set to JDK 8 until minimum JDK is bumped to 11 so we do not include this source set in our IDEs
 if (!isEclipse) {
@@ -75,8 +76,15 @@ if (!isEclipse) {
 }
 
 dependencies {
-  // This dependency is used only by :libs:core for null-checking interop with other tools
-  compileOnly "com.google.code.findbugs:jsr305:3.0.2"
+  api project(':libs:opensearch-common')
+
+  api "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
+
+  // lucene
+  api "org.apache.lucene:lucene-core:${versions.lucene}"
+
+  // logging
+  api "org.apache.logging.log4j:log4j-api:${versions.log4j}"
 
   testImplementation "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
   testImplementation "junit:junit:${versions.junit}"
@@ -93,15 +101,23 @@ tasks.named('forbiddenApisMain').configure {
   replaceSignatureFiles 'jdk-signatures'
 }
 
-thirdPartyAudit.ignoreMissingClasses(
-  // from log4j
-  'org/osgi/framework/AdaptPermission',
-  'org/osgi/framework/AdminPermission',
-  'org/osgi/framework/Bundle',
-  'org/osgi/framework/BundleActivator',
-  'org/osgi/framework/BundleContext',
-  'org/osgi/framework/BundleEvent',
-  'org/osgi/framework/SynchronousBundleListener',
-  'org/osgi/framework/wiring/BundleWire',
-  'org/osgi/framework/wiring/BundleWiring'
-)
+tasks.named("thirdPartyAudit").configure {
+  ignoreMissingClasses(
+    // from log4j
+    'org.osgi.framework.Bundle',
+    'org.osgi.framework.BundleActivator',
+    'org.osgi.framework.BundleContext',
+    'org.osgi.framework.BundleEvent',
+    'org.osgi.framework.FrameworkUtil',
+    'org.osgi.framework.ServiceReference',
+    'org.osgi.framework.ServiceRegistration',
+    'org.osgi.framework.SynchronousBundleListener',
+    'org.osgi.framework.wiring.BundleWire',
+    'org.osgi.framework.wiring.BundleWiring'
+  )
+}
+
+tasks.named("dependencyLicenses").configure {
+  mapping from: /jackson-.*/, to: 'jackson'
+  mapping from: /lucene-.*/, to: 'lucene'
+}
diff --git a/plugins/repository-azure/licenses/jackson-LICENSE b/libs/core/licenses/jackson-LICENSE
similarity index 100%
rename from plugins/repository-azure/licenses/jackson-LICENSE
rename to libs/core/licenses/jackson-LICENSE
diff --git a/plugins/repository-azure/licenses/jackson-NOTICE b/libs/core/licenses/jackson-NOTICE
similarity index 100%
rename from plugins/repository-azure/licenses/jackson-NOTICE
rename to libs/core/licenses/jackson-NOTICE
diff --git a/libs/core/licenses/jackson-core-2.15.2.jar.sha1 b/libs/core/licenses/jackson-core-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..ec6781b968eed
--- /dev/null
+++ b/libs/core/licenses/jackson-core-2.15.2.jar.sha1
@@ -0,0 +1 @@
+a6fe1836469a69b3ff66037c324d75fc66ef137c
\ No newline at end of file
diff --git a/libs/core/licenses/log4j-api-2.20.0.jar.sha1 b/libs/core/licenses/log4j-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..37154d9861ac0
--- /dev/null
+++ b/libs/core/licenses/log4j-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+1fe6082e660daf07c689a89c94dc0f49c26b44bb
\ No newline at end of file
diff --git a/libs/core/licenses/log4j-api-LICENSE.txt b/libs/core/licenses/log4j-api-LICENSE.txt
new file mode 100644
index 0000000000000..6279e5206de13
--- /dev/null
+++ b/libs/core/licenses/log4j-api-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 1999-2005 The Apache Software Foundation
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/libs/core/licenses/log4j-api-NOTICE.txt b/libs/core/licenses/log4j-api-NOTICE.txt
new file mode 100644
index 0000000000000..0375732360047
--- /dev/null
+++ b/libs/core/licenses/log4j-api-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache log4j
+Copyright 2007 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
\ No newline at end of file
diff --git a/libs/core/licenses/lucene-LICENSE.txt b/libs/core/licenses/lucene-LICENSE.txt
new file mode 100644
index 0000000000000..28b134f5f8e4d
--- /dev/null
+++ b/libs/core/licenses/lucene-LICENSE.txt
@@ -0,0 +1,475 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+
+
+Some code in core/src/java/org/apache/lucene/util/UnicodeUtil.java was
+derived from unicode conversion examples available at
+http://www.unicode.org/Public/PROGRAMS/CVTUTF.  Here is the copyright
+from those sources:
+
+/*
+ * Copyright 2001-2004 Unicode, Inc.
+ * 
+ * Disclaimer
+ * 
+ * This source code is provided as is by Unicode, Inc. No claims are
+ * made as to fitness for any particular purpose. No warranties of any
+ * kind are expressed or implied. The recipient agrees to determine
+ * applicability of information provided. If this file has been
+ * purchased on magnetic or optical media from Unicode, Inc., the
+ * sole remedy for any claim will be exchange of defective media
+ * within 90 days of receipt.
+ * 
+ * Limitations on Rights to Redistribute This Code
+ * 
+ * Unicode, Inc. hereby grants the right to freely use the information
+ * supplied in this file in the creation of products supporting the
+ * Unicode Standard, and to make copies of this file in any form
+ * for internal or external distribution as long as this notice
+ * remains attached.
+ */
+
+
+Some code in core/src/java/org/apache/lucene/util/ArrayUtil.java was
+derived from Python 2.4.2 sources available at
+http://www.python.org. Full license is here:
+
+  http://www.python.org/download/releases/2.4.2/license/
+
+Some code in core/src/java/org/apache/lucene/util/UnicodeUtil.java was
+derived from Python 3.1.2 sources available at
+http://www.python.org. Full license is here:
+
+  http://www.python.org/download/releases/3.1.2/license/
+
+Some code in core/src/java/org/apache/lucene/util/automaton was
+derived from Brics automaton sources available at
+www.brics.dk/automaton/. Here is the copyright from those sources:
+
+/*
+ * Copyright (c) 2001-2009 Anders Moeller
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+ 
+The levenshtein automata tables in core/src/java/org/apache/lucene/util/automaton 
+were automatically generated with the moman/finenight FSA package.
+Here is the copyright for those sources:
+
+# Copyright (c) 2010, Jean-Philippe Barrette-LaPierre, <jpb@rrette.com>
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation
+# files (the "Software"), to deal in the Software without
+# restriction, including without limitation the rights to use,
+# copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following
+# conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+
+Some code in core/src/java/org/apache/lucene/util/UnicodeUtil.java was
+derived from ICU (http://www.icu-project.org)
+The full license is available here: 
+  http://source.icu-project.org/repos/icu/icu/trunk/license.html
+
+/*
+ * Copyright (C) 1999-2010, International Business Machines
+ * Corporation and others.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy 
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights 
+ * to use, copy, modify, merge, publish, distribute, and/or sell copies of the 
+ * Software, and to permit persons to whom the Software is furnished to do so, 
+ * provided that the above copyright notice(s) and this permission notice appear 
+ * in all copies of the Software and that both the above copyright notice(s) and
+ * this permission notice appear in supporting documentation.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. 
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE BE 
+ * LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR 
+ * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER 
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 
+ * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Except as contained in this notice, the name of a copyright holder shall not 
+ * be used in advertising or otherwise to promote the sale, use or other 
+ * dealings in this Software without prior written authorization of the 
+ * copyright holder.
+ */
+ 
+The following license applies to the Snowball stemmers:
+
+Copyright (c) 2001, Dr Martin Porter
+Copyright (c) 2002, Richard Boulton
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice,
+    * this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+    * notice, this list of conditions and the following disclaimer in the
+    * documentation and/or other materials provided with the distribution.
+    * Neither the name of the copyright holders nor the names of its contributors
+    * may be used to endorse or promote products derived from this software
+    * without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+The following license applies to the KStemmer:
+
+Copyright © 2003,
+Center for Intelligent Information Retrieval,
+University of Massachusetts, Amherst.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+3. The names "Center for Intelligent Information Retrieval" and
+"University of Massachusetts" must not be used to endorse or promote products
+derived from this software without prior written permission. To obtain
+permission, contact info@ciir.cs.umass.edu.
+
+THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF MASSACHUSETTS AND OTHER CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
+
+The following license applies to the Morfologik project:
+
+Copyright (c) 2006 Dawid Weiss
+Copyright (c) 2007-2011 Dawid Weiss, Marcin Miłkowski
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, 
+are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice, 
+    this list of conditions and the following disclaimer.
+    
+    * Redistributions in binary form must reproduce the above copyright notice, 
+    this list of conditions and the following disclaimer in the documentation 
+    and/or other materials provided with the distribution.
+    
+    * Neither the name of Morfologik nor the names of its contributors 
+    may be used to endorse or promote products derived from this software 
+    without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR 
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+---
+
+The dictionary comes from Morfologik project. Morfologik uses data from 
+Polish ispell/myspell dictionary hosted at http://www.sjp.pl/slownik/en/ and 
+is licenced on the terms of (inter alia) LGPL and Creative Commons 
+ShareAlike. The part-of-speech tags were added in Morfologik project and
+are not found in the data from sjp.pl. The tagset is similar to IPI PAN
+tagset.
+
+---
+
+The following license applies to the Morfeusz project,
+used by org.apache.lucene.analysis.morfologik.
+
+BSD-licensed dictionary of Polish (SGJP)
+http://sgjp.pl/morfeusz/
+
+Copyright © 2011 Zygmunt Saloni, Włodzimierz Gruszczyński, 
+             Marcin Woliński, Robert Wołosz
+
+All rights reserved.
+
+Redistribution and  use in  source and binary  forms, with  or without
+modification, are permitted provided that the following conditions are
+met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the
+   distribution.
+
+THIS SOFTWARE IS PROVIDED BY COPYRIGHT HOLDERS “AS IS” AND ANY EXPRESS
+OR  IMPLIED WARRANTIES,  INCLUDING, BUT  NOT LIMITED  TO,  THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED.  IN NO EVENT  SHALL COPYRIGHT  HOLDERS OR  CONTRIBUTORS BE
+LIABLE FOR  ANY DIRECT,  INDIRECT, INCIDENTAL, SPECIAL,  EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES  (INCLUDING, BUT NOT LIMITED  TO, PROCUREMENT OF
+SUBSTITUTE  GOODS OR  SERVICES;  LOSS  OF USE,  DATA,  OR PROFITS;  OR
+BUSINESS INTERRUPTION) HOWEVER CAUSED  AND ON ANY THEORY OF LIABILITY,
+WHETHER IN  CONTRACT, STRICT LIABILITY, OR  TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/libs/core/licenses/lucene-NOTICE.txt b/libs/core/licenses/lucene-NOTICE.txt
new file mode 100644
index 0000000000000..1a1d51572432a
--- /dev/null
+++ b/libs/core/licenses/lucene-NOTICE.txt
@@ -0,0 +1,192 @@
+Apache Lucene
+Copyright 2014 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+
+Includes software from other Apache Software Foundation projects,
+including, but not limited to:
+ - Apache Ant
+ - Apache Jakarta Regexp
+ - Apache Commons
+ - Apache Xerces
+
+ICU4J, (under analysis/icu) is licensed under an MIT styles license
+and Copyright (c) 1995-2008 International Business Machines Corporation and others
+
+Some data files (under analysis/icu/src/data) are derived from Unicode data such
+as the Unicode Character Database. See http://unicode.org/copyright.html for more
+details.
+
+Brics Automaton (under core/src/java/org/apache/lucene/util/automaton) is 
+BSD-licensed, created by Anders Møller. See http://www.brics.dk/automaton/
+
+The levenshtein automata tables (under core/src/java/org/apache/lucene/util/automaton) were
+automatically generated with the moman/finenight FSA library, created by
+Jean-Philippe Barrette-LaPierre. This library is available under an MIT license,
+see http://sites.google.com/site/rrettesite/moman and 
+http://bitbucket.org/jpbarrette/moman/overview/
+
+The class org.apache.lucene.util.WeakIdentityMap was derived from
+the Apache CXF project and is Apache License 2.0.
+
+The Google Code Prettify is Apache License 2.0.
+See http://code.google.com/p/google-code-prettify/
+
+JUnit (junit-4.10) is licensed under the Common Public License v. 1.0
+See http://junit.sourceforge.net/cpl-v10.html
+
+This product includes code (JaspellTernarySearchTrie) from Java Spelling Checkin
+g Package (jaspell): http://jaspell.sourceforge.net/
+License: The BSD License (http://www.opensource.org/licenses/bsd-license.php)
+
+The snowball stemmers in
+  analysis/common/src/java/net/sf/snowball
+were developed by Martin Porter and Richard Boulton.
+The snowball stopword lists in
+  analysis/common/src/resources/org/apache/lucene/analysis/snowball
+were developed by Martin Porter and Richard Boulton.
+The full snowball package is available from
+  http://snowball.tartarus.org/
+
+The KStem stemmer in
+  analysis/common/src/org/apache/lucene/analysis/en
+was developed by Bob Krovetz and Sergio Guzman-Lara (CIIR-UMass Amherst)
+under the BSD-license.
+
+The Arabic,Persian,Romanian,Bulgarian, Hindi and Bengali analyzers (common) come with a default
+stopword list that is BSD-licensed created by Jacques Savoy.  These files reside in:
+analysis/common/src/resources/org/apache/lucene/analysis/ar/stopwords.txt,
+analysis/common/src/resources/org/apache/lucene/analysis/fa/stopwords.txt,
+analysis/common/src/resources/org/apache/lucene/analysis/ro/stopwords.txt,
+analysis/common/src/resources/org/apache/lucene/analysis/bg/stopwords.txt,
+analysis/common/src/resources/org/apache/lucene/analysis/hi/stopwords.txt,
+analysis/common/src/resources/org/apache/lucene/analysis/bn/stopwords.txt
+See http://members.unine.ch/jacques.savoy/clef/index.html.
+
+The German,Spanish,Finnish,French,Hungarian,Italian,Portuguese,Russian and Swedish light stemmers
+(common) are based on BSD-licensed reference implementations created by Jacques Savoy and
+Ljiljana Dolamic. These files reside in:
+analysis/common/src/java/org/apache/lucene/analysis/de/GermanLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/de/GermanMinimalStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/es/SpanishLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/fi/FinnishLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/fr/FrenchLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/fr/FrenchMinimalStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/hu/HungarianLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/it/ItalianLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/pt/PortugueseLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/ru/RussianLightStemmer.java
+analysis/common/src/java/org/apache/lucene/analysis/sv/SwedishLightStemmer.java
+
+The Stempel analyzer (stempel) includes BSD-licensed software developed 
+by the Egothor project http://egothor.sf.net/, created by Leo Galambos, Martin Kvapil,
+and Edmond Nolan.
+
+The Polish analyzer (stempel) comes with a default
+stopword list that is BSD-licensed created by the Carrot2 project. The file resides
+in stempel/src/resources/org/apache/lucene/analysis/pl/stopwords.txt.
+See http://project.carrot2.org/license.html.
+
+The SmartChineseAnalyzer source code (smartcn) was
+provided by Xiaoping Gao and copyright 2009 by www.imdict.net.
+
+WordBreakTestUnicode_*.java (under modules/analysis/common/src/test/) 
+is derived from Unicode data such as the Unicode Character Database. 
+See http://unicode.org/copyright.html for more details.
+
+The Morfologik analyzer (morfologik) includes BSD-licensed software
+developed by Dawid Weiss and Marcin Miłkowski (http://morfologik.blogspot.com/).
+
+Morfologik uses data from Polish ispell/myspell dictionary
+(http://www.sjp.pl/slownik/en/) licenced on the terms of (inter alia)
+LGPL and Creative Commons ShareAlike.
+
+Morfologic includes data from BSD-licensed dictionary of Polish (SGJP)
+(http://sgjp.pl/morfeusz/)
+
+Servlet-api.jar and javax.servlet-*.jar are under the CDDL license, the original
+source code for this can be found at http://www.eclipse.org/jetty/downloads.php
+
+===========================================================================
+Kuromoji Japanese Morphological Analyzer - Apache Lucene Integration
+===========================================================================
+
+This software includes a binary and/or source version of data from
+
+  mecab-ipadic-2.7.0-20070801
+
+which can be obtained from
+
+  http://atilika.com/releases/mecab-ipadic/mecab-ipadic-2.7.0-20070801.tar.gz
+
+or
+
+  http://jaist.dl.sourceforge.net/project/mecab/mecab-ipadic/2.7.0-20070801/mecab-ipadic-2.7.0-20070801.tar.gz
+
+===========================================================================
+mecab-ipadic-2.7.0-20070801 Notice
+===========================================================================
+
+Nara Institute of Science and Technology (NAIST),
+the copyright holders, disclaims all warranties with regard to this
+software, including all implied warranties of merchantability and
+fitness, in no event shall NAIST be liable for
+any special, indirect or consequential damages or any damages
+whatsoever resulting from loss of use, data or profits, whether in an
+action of contract, negligence or other tortuous action, arising out
+of or in connection with the use or performance of this software.
+
+A large portion of the dictionary entries
+originate from ICOT Free Software.  The following conditions for ICOT
+Free Software applies to the current dictionary as well.
+
+Each User may also freely distribute the Program, whether in its
+original form or modified, to any third party or parties, PROVIDED
+that the provisions of Section 3 ("NO WARRANTY") will ALWAYS appear
+on, or be attached to, the Program, which is distributed substantially
+in the same form as set out herein and that such intended
+distribution, if actually made, will neither violate or otherwise
+contravene any of the laws and regulations of the countries having
+jurisdiction over the User or the intended distribution itself.
+
+NO WARRANTY
+
+The program was produced on an experimental basis in the course of the
+research and development conducted during the project and is provided
+to users as so produced on an experimental basis.  Accordingly, the
+program is provided without any warranty whatsoever, whether express,
+implied, statutory or otherwise.  The term "warranty" used herein
+includes, but is not limited to, any warranty of the quality,
+performance, merchantability and fitness for a particular purpose of
+the program and the nonexistence of any infringement or violation of
+any right of any third party.
+
+Each user of the program will agree and understand, and be deemed to
+have agreed and understood, that there is no warranty whatsoever for
+the program and, accordingly, the entire risk arising from or
+otherwise connected with the program is assumed by the user.
+
+Therefore, neither ICOT, the copyright holder, or any other
+organization that participated in or was otherwise related to the
+development of the program and their respective officials, directors,
+officers and other employees shall be held liable for any and all
+damages, including, without limitation, general, special, incidental
+and consequential damages, arising out of or otherwise in connection
+with the use or inability to use the program or any product, material
+or result produced or otherwise obtained by using the program,
+regardless of whether they have been advised of, or otherwise had
+knowledge of, the possibility of such damages at any time during the
+project or thereafter.  Each user will be deemed to have agreed to the
+foregoing by his or her commencement of use of the program.  The term
+"use" as used herein includes, but is not limited to, the use,
+modification, copying and distribution of the program and the
+production of secondary products from the program.
+
+In the case where the program, whether in its original form or
+modified, was distributed or delivered to or received by a user from
+any person, organization or entity other than ICOT, unless it makes or
+grants independently of ICOT any specific warranty to the user in
+writing, such person, organization or entity, will also be exempted
+from and not be held liable to the user for any such damages as noted
+above as far as the program is concerned.
diff --git a/libs/core/licenses/lucene-core-9.7.0.jar.sha1 b/libs/core/licenses/lucene-core-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..2b0f77275c0ab
--- /dev/null
+++ b/libs/core/licenses/lucene-core-9.7.0.jar.sha1
@@ -0,0 +1 @@
+ad391210ffd806931334be9670a35af00c56f959
\ No newline at end of file
diff --git a/server/src/main/java/org/opensearch/Build.java b/libs/core/src/main/java/org/opensearch/Build.java
similarity index 75%
rename from server/src/main/java/org/opensearch/Build.java
rename to libs/core/src/main/java/org/opensearch/Build.java
index 9508a63de5991..67a50a8a31a0e 100644
--- a/server/src/main/java/org/opensearch/Build.java
+++ b/libs/core/src/main/java/org/opensearch/Build.java
@@ -33,9 +33,7 @@
 package org.opensearch;
 
 import org.opensearch.common.Booleans;
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.util.FileSystemUtils;
 
 import java.io.IOException;
 import java.net.URL;
@@ -46,6 +44,8 @@
 
 /**
  * Information about a build of OpenSearch.
+ *
+ * @opensearch.internal
  */
 public class Build {
     /**
@@ -54,6 +54,11 @@ public class Build {
      */
     public static final Build CURRENT;
 
+    /**
+     * The type of build
+     *
+     * @opensearch.internal
+     */
     public enum Type {
 
         DEB("deb"),
@@ -109,12 +114,14 @@ public static Type fromDisplayName(final String displayName, final boolean stric
         // these are parsed at startup, and we require that we are able to recognize the values passed in by the startup scripts
         type = Type.fromDisplayName(System.getProperty("opensearch.distribution.type", "unknown"), true);
 
-        final String opensearchPrefix = distribution + "-" + Version.CURRENT;
+        final String opensearchPrefix = distribution;
         final URL url = getOpenSearchCodeSourceLocation();
         final String urlStr = url == null ? "" : url.toString();
         if (urlStr.startsWith("file:/")
-            && (urlStr.endsWith(opensearchPrefix + ".jar")
-                || urlStr.matches("(.*)" + opensearchPrefix + "(-)?((alpha|beta|rc)[0-9]+)?(-SNAPSHOT)?.jar"))) {
+            && (urlStr.endsWith(opensearchPrefix + "-" + Version.CURRENT + ".jar")
+                || urlStr.matches(
+                    "(.*)" + opensearchPrefix + "(-)?(.*?)" + Version.CURRENT + "(-)?((alpha|beta|rc)[0-9]+)?(-SNAPSHOT)?.jar"
+                ))) {
             try (JarInputStream jar = new JarInputStream(FileSystemUtils.openFileURLStream(url))) {
                 Manifest manifest = jar.getManifest();
                 hash = manifest.getMainAttributes().getValue("Change");
@@ -199,61 +206,6 @@ public String date() {
         return date;
     }
 
-    public static Build readBuild(StreamInput in) throws IOException {
-        final String distribution;
-        final Type type;
-        // the following is new for opensearch: we write the distribution to support any "forks"
-        if (in.getVersion().onOrAfter(Version.V_1_0_0)) {
-            distribution = in.readString();
-        } else {
-            distribution = "other";
-        }
-
-        // The following block is kept for existing BWS tests to pass.
-        // TODO - clean up this code when we remove all v6 bwc tests.
-        // TODO - clean this up when OSS flavor is removed in all of the code base
-        // (Integ test zip still write OSS as distribution)
-        // See issue: https://github.com/opendistro-for-elasticsearch/search/issues/159
-        if (in.getVersion().before(Version.V_1_3_0)) {
-            String flavor = in.readString();
-        }
-        // be lenient when reading on the wire, the enumeration values from other versions might be different than what we know
-        type = Type.fromDisplayName(in.readString(), false);
-        String hash = in.readString();
-        String date = in.readString();
-        boolean snapshot = in.readBoolean();
-
-        final String version;
-        if (in.getVersion().onOrAfter(LegacyESVersion.V_7_0_0)) {
-            version = in.readString();
-        } else {
-            version = in.getVersion().toString();
-        }
-        return new Build(type, hash, date, snapshot, version, distribution);
-    }
-
-    public static void writeBuild(Build build, StreamOutput out) throws IOException {
-        // the following is new for opensearch: we write the distribution name to support any "forks" of the code
-        if (out.getVersion().onOrAfter(Version.V_1_0_0)) {
-            out.writeString(build.distribution);
-        }
-
-        // The following block is kept for existing BWS tests to pass.
-        // TODO - clean up this code when we remove all v6 bwc tests.
-        // TODO - clean this up when OSS flavor is removed in all of the code base
-        if (out.getVersion().before(Version.V_1_3_0)) {
-            out.writeString("oss");
-        }
-        final Type buildType = build.type();
-        out.writeString(buildType.displayName());
-        out.writeString(build.hash());
-        out.writeString(build.date());
-        out.writeBoolean(build.isSnapshot());
-        if (out.getVersion().onOrAfter(LegacyESVersion.V_7_0_0)) {
-            out.writeString(build.getQualifiedVersion());
-        }
-    }
-
     /**
      * Get the distribution name (expected to be OpenSearch; empty if legacy; something else if forked)
      * @return distribution name as a string
diff --git a/server/src/main/java/org/opensearch/ExceptionsHelper.java b/libs/core/src/main/java/org/opensearch/ExceptionsHelper.java
similarity index 86%
rename from server/src/main/java/org/opensearch/ExceptionsHelper.java
rename to libs/core/src/main/java/org/opensearch/ExceptionsHelper.java
index 418bf9811a7b3..fa1da858d0b42 100644
--- a/server/src/main/java/org/opensearch/ExceptionsHelper.java
+++ b/libs/core/src/main/java/org/opensearch/ExceptionsHelper.java
@@ -33,16 +33,19 @@
 package org.opensearch;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
 import org.apache.lucene.index.IndexFormatTooOldException;
-import org.opensearch.action.ShardOperationFailedException;
+import org.opensearch.common.CheckedRunnable;
+import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.io.PrintWriter;
@@ -61,10 +64,19 @@
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
-public final class ExceptionsHelper {
+import static org.opensearch.OpenSearchException.getExceptionSimpleClassName;
 
+/**
+ * Helper class for OpenSearch Exceptions
+ *
+ * @opensearch.internal
+ */
+public final class ExceptionsHelper {
     private static final Logger logger = LogManager.getLogger(ExceptionsHelper.class);
 
+    // utility class: no ctor
+    private ExceptionsHelper() {}
+
     public static RuntimeException convertToRuntime(Exception e) {
         if (e instanceof RuntimeException) {
             return (RuntimeException) e;
@@ -94,6 +106,21 @@ public static RestStatus status(Throwable t) {
         return RestStatus.INTERNAL_SERVER_ERROR;
     }
 
+    public static String summaryMessage(Throwable t) {
+        if (t != null) {
+            if (t instanceof OpenSearchException) {
+                return getExceptionSimpleClassName(t) + "[" + t.getMessage() + "]";
+            } else if (t instanceof IllegalArgumentException) {
+                return "Invalid argument";
+            } else if (t instanceof JsonParseException) {
+                return "Failed to parse JSON";
+            } else if (t instanceof OpenSearchRejectedExecutionException) {
+                return "Too many requests";
+            }
+        }
+        return "Internal failure";
+    }
+
     public static Throwable unwrapCause(Throwable t) {
         int counter = 0;
         Throwable result = t;
@@ -125,7 +152,7 @@ public static String detailedMessage(Throwable t) {
         if (t.getCause() != null) {
             StringBuilder sb = new StringBuilder();
             while (t != null) {
-                sb.append(t.getClass().getSimpleName());
+                sb.append(getExceptionSimpleClassName(t));
                 if (t.getMessage() != null) {
                     sb.append("[");
                     sb.append(t.getMessage());
@@ -139,7 +166,7 @@ public static String detailedMessage(Throwable t) {
             }
             return sb.toString();
         } else {
-            return t.getClass().getSimpleName() + "[" + t.getMessage() + "]";
+            return getExceptionSimpleClassName(t) + "[" + t.getMessage() + "]";
         }
     }
 
@@ -315,6 +342,32 @@ public static void maybeDieOnAnotherThread(final Throwable throwable) {
         });
     }
 
+    /**
+     * Run passed runnable and catch exception and translate exception into runtime exception using
+     * {@link ExceptionsHelper#convertToRuntime(Exception)}
+     * @param supplier to run
+     */
+    public static <R, E extends Exception> R catchAsRuntimeException(CheckedSupplier<R, E> supplier) {
+        try {
+            return supplier.get();
+        } catch (Exception e) {
+            throw convertToRuntime(e);
+        }
+    }
+
+    /**
+     * Run passed runnable and catch exception and translate exception into runtime exception using
+     * {@link ExceptionsHelper#convertToRuntime(Exception)}
+     * @param runnable to run
+     */
+    public static void catchAsRuntimeException(CheckedRunnable<Exception> runnable) {
+        try {
+            runnable.run();
+        } catch (Exception e) {
+            throw convertToRuntime(e);
+        }
+    }
+
     /**
      * Deduplicate the failures by exception message and index.
      */
diff --git a/server/src/main/java/org/opensearch/LegacyESVersion.java b/libs/core/src/main/java/org/opensearch/LegacyESVersion.java
similarity index 95%
rename from server/src/main/java/org/opensearch/LegacyESVersion.java
rename to libs/core/src/main/java/org/opensearch/LegacyESVersion.java
index 38b655b09b151..dafd071ef935a 100644
--- a/server/src/main/java/org/opensearch/LegacyESVersion.java
+++ b/libs/core/src/main/java/org/opensearch/LegacyESVersion.java
@@ -32,17 +32,19 @@
 
 package org.opensearch;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.core.Assertions;
 
 import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * The Contents of this file were originally moved from {@link Version}.
  *
  * This class keeps all the supported OpenSearch predecessor versions for
  * backward compatibility purpose.
+ *
+ * @opensearch.internal
  */
 public class LegacyESVersion extends Version {
 
@@ -77,11 +79,11 @@ public class LegacyESVersion extends Version {
     public static final LegacyESVersion V_7_10_2 = new LegacyESVersion(7100299, org.apache.lucene.util.Version.LUCENE_8_7_0);
 
     // todo move back to Version.java if retiring legacy version support
-    protected static final ImmutableOpenIntMap<Version> idToVersion;
-    protected static final ImmutableOpenMap<String, Version> stringToVersion;
+    protected static final Map<Integer, Version> idToVersion;
+    protected static final Map<String, Version> stringToVersion;
     static {
-        final ImmutableOpenIntMap.Builder<Version> builder = ImmutableOpenIntMap.builder();
-        final ImmutableOpenMap.Builder<String, Version> builderByString = ImmutableOpenMap.builder();
+        final Map<Integer, Version> builder = new HashMap<>();
+        final Map<String, Version> builderByString = new HashMap<>();
 
         for (final Field declaredField : LegacyESVersion.class.getFields()) {
             if (declaredField.getType().equals(Version.class) || declaredField.getType().equals(LegacyESVersion.class)) {
@@ -143,8 +145,8 @@ public class LegacyESVersion extends Version {
 
         builder.put(V_EMPTY_ID, V_EMPTY);
         builderByString.put(V_EMPTY.toString(), V_EMPTY);
-        idToVersion = builder.build();
-        stringToVersion = builderByString.build();
+        idToVersion = Map.copyOf(builder);
+        stringToVersion = Map.copyOf(builderByString);
     }
 
     protected LegacyESVersion(int id, org.apache.lucene.util.Version luceneVersion) {
@@ -173,7 +175,7 @@ public boolean isAlpha() {
      * Returns the version given its string representation, current version if the argument is null or empty
      */
     public static Version fromString(String version) {
-        if (!Strings.hasLength(version)) {
+        if (stringHasLength(version) == false) {
             return Version.CURRENT;
         }
         final Version cached = stringToVersion.get(version);
diff --git a/libs/core/src/main/java/org/opensearch/OpenSearchException.java b/libs/core/src/main/java/org/opensearch/OpenSearchException.java
new file mode 100644
index 0000000000000..5bad711a15032
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/OpenSearchException.java
@@ -0,0 +1,1003 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch;
+
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.logging.LoggerMessageFormat;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonMap;
+import static org.opensearch.OpenSearchException.OpenSearchExceptionHandleRegistry.registerExceptionHandle;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureFieldName;
+
+/**
+ * A core library base class for all opensearch exceptions.
+ *
+ * @opensearch.internal
+ */
+public class OpenSearchException extends RuntimeException implements Writeable, ToXContentFragment {
+
+    protected static final Version UNKNOWN_VERSION_ADDED = Version.fromId(0);
+
+    /**
+     * Passed in the {@link ToXContent.Params} of {@link #generateThrowableXContent(XContentBuilder, ToXContent.Params, Throwable)}
+     * to control if the {@code caused_by} element should render. Unlike most parameters to {@code toXContent} methods this parameter is
+     * internal only and not available as a URL parameter.
+     */
+    private static final String REST_EXCEPTION_SKIP_CAUSE = "rest.exception.cause.skip";
+    /**
+     * Passed in the {@link ToXContent.Params} of {@link #generateThrowableXContent(XContentBuilder, ToXContent.Params, Throwable)}
+     * to control if the {@code stack_trace} element should render. Unlike most parameters to {@code toXContent} methods this parameter is
+     * internal only and not available as a URL parameter. Use the {@code error_trace} parameter instead.
+     */
+    public static final String REST_EXCEPTION_SKIP_STACK_TRACE = "rest.exception.stacktrace.skip";
+    public static final boolean REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT = true;
+    private static final boolean REST_EXCEPTION_SKIP_CAUSE_DEFAULT = false;
+    private static final String RESOURCE_METADATA_TYPE_KEY = "opensearch.resource.type";
+    private static final String RESOURCE_METADATA_ID_KEY = "opensearch.resource.id";
+    private static final String INDEX_METADATA_KEY = "opensearch.index";
+    private static final String INDEX_METADATA_KEY_UUID = "opensearch.index_uuid";
+    private static final String SHARD_METADATA_KEY = "opensearch.shard";
+    private static final String OPENSEARCH_PREFIX_KEY = "opensearch.";
+
+    private static final String TYPE = "type";
+    private static final String REASON = "reason";
+    private static final String CAUSED_BY = "caused_by";
+    private static final ParseField SUPPRESSED = new ParseField("suppressed");
+    public static final String STACK_TRACE = "stack_trace";
+    private static final String HEADER = "header";
+    private static final String ERROR = "error";
+    private static final String ROOT_CAUSE = "root_cause";
+
+    protected final Map<String, List<String>> metadata = new HashMap<>();
+    protected final Map<String, List<String>> headers = new HashMap<>();
+
+    static {
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException.class,
+                org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException::new,
+                0,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchParseException.class,
+                org.opensearch.OpenSearchParseException::new,
+                35,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.common.ParsingException.class,
+                org.opensearch.core.common.ParsingException::new,
+                40,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.common.io.stream.NotSerializableExceptionWrapper.class,
+                org.opensearch.core.common.io.stream.NotSerializableExceptionWrapper::new,
+                62,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.common.breaker.CircuitBreakingException.class,
+                org.opensearch.core.common.breaker.CircuitBreakingException::new,
+                133,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.tasks.TaskCancelledException.class,
+                org.opensearch.core.tasks.TaskCancelledException::new,
+                146,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+    }
+
+    /**
+     * Construct a <code>OpenSearchException</code> with the specified cause exception.
+     */
+    public OpenSearchException(Throwable cause) {
+        super(cause);
+    }
+
+    /**
+     * Construct a <code>OpenSearchException</code> with the specified detail message.
+     *
+     * The message can be parameterized using <code>{}</code> as placeholders for the given
+     * arguments
+     *
+     * @param msg  the detail message
+     * @param args the arguments for the message
+     */
+    public OpenSearchException(String msg, Object... args) {
+        super(LoggerMessageFormat.format(msg, args));
+    }
+
+    /**
+     * Construct a <code>OpenSearchException</code> with the specified detail message
+     * and nested exception.
+     *
+     * The message can be parameterized using <code>{}</code> as placeholders for the given
+     * arguments
+     *
+     * @param msg   the detail message
+     * @param cause the nested exception
+     * @param args  the arguments for the message
+     */
+    public OpenSearchException(String msg, Throwable cause, Object... args) {
+        super(LoggerMessageFormat.format(msg, args), cause);
+    }
+
+    public OpenSearchException(StreamInput in) throws IOException {
+        this(in.readOptionalString(), in.readException());
+        readStackTrace(this, in);
+        headers.putAll(in.readMapOfLists(StreamInput::readString, StreamInput::readString));
+        metadata.putAll(in.readMapOfLists(StreamInput::readString, StreamInput::readString));
+    }
+
+    @Override
+    public void writeTo(final StreamOutput out) throws IOException {
+        out.writeOptionalString(this.getMessage());
+        out.writeException(this.getCause());
+        writeStackTraces(this, out, StreamOutput::writeException);
+        out.writeMapOfLists(headers, StreamOutput::writeString, StreamOutput::writeString);
+        out.writeMapOfLists(metadata, StreamOutput::writeString, StreamOutput::writeString);
+    }
+
+    /**
+     * Adds a new piece of metadata with the given key.
+     * If the provided key is already present, the corresponding metadata will be replaced
+     */
+    public void addMetadata(String key, String... values) {
+        addMetadata(key, Arrays.asList(values));
+    }
+
+    /**
+     * Adds a new piece of metadata with the given key.
+     * If the provided key is already present, the corresponding metadata will be replaced
+     */
+    public void addMetadata(String key, List<String> values) {
+        // we need to enforce this otherwise bw comp doesn't work properly, as "opensearch."
+        // was the previous criteria to split headers in two sets
+        if (key.startsWith(OPENSEARCH_PREFIX_KEY) == false) {
+            throw new IllegalArgumentException("exception metadata must start with [opensearch.], found [" + key + "] instead");
+        }
+        this.metadata.put(key, values);
+    }
+
+    /**
+     * Returns a set of all metadata keys on this exception
+     */
+    public Set<String> getMetadataKeys() {
+        return metadata.keySet();
+    }
+
+    /**
+     * Returns the list of metadata values for the given key or {@code null} if no metadata for the
+     * given key exists.
+     */
+    public List<String> getMetadata(String key) {
+        return metadata.get(key);
+    }
+
+    protected Map<String, List<String>> getMetadata() {
+        return metadata;
+    }
+
+    /**
+     * Adds a new header with the given key.
+     * This method will replace existing header if a header with the same key already exists
+     */
+    public void addHeader(String key, List<String> value) {
+        // we need to enforce this otherwise bw comp doesn't work properly, as "opensearch."
+        // was the previous criteria to split headers in two sets
+        if (key.startsWith(OPENSEARCH_PREFIX_KEY)) {
+            throw new IllegalArgumentException("exception headers must not start with [opensearch.], found [" + key + "] instead");
+        }
+        this.headers.put(key, value);
+    }
+
+    /**
+     * Adds a new header with the given key.
+     * This method will replace existing header if a header with the same key already exists
+     */
+    public void addHeader(String key, String... value) {
+        addHeader(key, Arrays.asList(value));
+    }
+
+    /**
+     * Returns a set of all header keys on this exception
+     */
+    public Set<String> getHeaderKeys() {
+        return headers.keySet();
+    }
+
+    /**
+     * Returns the list of header values for the given key or {@code null} if no header for the
+     * given key exists.
+     */
+    public List<String> getHeader(String key) {
+        return headers.get(key);
+    }
+
+    protected Map<String, List<String>> getHeaders() {
+        return headers;
+    }
+
+    /**
+     * Returns the rest status code associated with this exception.
+     */
+    public RestStatus status() {
+        Throwable cause = unwrapCause();
+        if (cause == this) {
+            return RestStatus.INTERNAL_SERVER_ERROR;
+        } else {
+            return ExceptionsHelper.status(cause);
+        }
+    }
+
+    /**
+     * Unwraps the actual cause from the exception for cases when the exception is a
+     * {@link OpenSearchWrapperException}.
+     *
+     * @see ExceptionsHelper#unwrapCause(Throwable)
+     */
+    public Throwable unwrapCause() {
+        return ExceptionsHelper.unwrapCause(this);
+    }
+
+    /**
+     * Return the detail message, including the message from the nested exception
+     * if there is one.
+     */
+    public String getDetailedMessage() {
+        if (getCause() != null) {
+            StringBuilder sb = new StringBuilder();
+            sb.append(toString()).append("; ");
+            if (getCause() instanceof OpenSearchException) {
+                sb.append(((OpenSearchException) getCause()).getDetailedMessage());
+            } else {
+                sb.append(getCause());
+            }
+            return sb.toString();
+        } else {
+            return toString();
+        }
+    }
+
+    /**
+     * Retrieve the innermost cause of this exception, if none, returns the current exception.
+     */
+    public Throwable getRootCause() {
+        Throwable rootCause = this;
+        Throwable cause = getCause();
+        while (cause != null && cause != rootCause) {
+            rootCause = cause;
+            cause = cause.getCause();
+        }
+        return rootCause;
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <T extends StreamInput> OpenSearchException readException(T input, int id) throws IOException {
+        CheckedFunction<T, ? extends OpenSearchException, IOException> opensearchException = (CheckedFunction<
+            T,
+            ? extends OpenSearchException,
+            IOException>) OpenSearchExceptionHandleRegistry.getSupplier(id);
+        if (opensearchException == null) {
+            throw new IllegalStateException("unknown exception for id: " + id);
+        }
+        return opensearchException.apply(input);
+    }
+
+    /**
+     * Returns <code>true</code> iff the given class is a registered for an exception to be read.
+     */
+    public static boolean isRegistered(final Class<? extends Throwable> exception, Version version) {
+        return OpenSearchExceptionHandleRegistry.isRegistered(exception, version);
+    }
+
+    static Set<Class<? extends OpenSearchException>> getRegisteredKeys() { // for testing
+        return OpenSearchExceptionHandleRegistry.getRegisteredKeys();
+    }
+
+    /**
+     * Returns the serialization id the given exception.
+     */
+    public static int getId(final Class<? extends OpenSearchException> exception) {
+        return OpenSearchExceptionHandleRegistry.getId(exception);
+    }
+
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        Throwable ex = ExceptionsHelper.unwrapCause(this);
+        if (ex != this) {
+            generateThrowableXContent(builder, params, this);
+        } else {
+            innerToXContent(builder, params, this, getExceptionName(), getMessage(), headers, metadata, getCause());
+        }
+        return builder;
+    }
+
+    protected static void innerToXContent(
+        XContentBuilder builder,
+        ToXContent.Params params,
+        Throwable throwable,
+        String type,
+        String message,
+        Map<String, List<String>> headers,
+        Map<String, List<String>> metadata,
+        Throwable cause
+    ) throws IOException {
+        builder.field(TYPE, type);
+        builder.field(REASON, message);
+
+        for (Map.Entry<String, List<String>> entry : metadata.entrySet()) {
+            headerToXContent(builder, entry.getKey().substring(OPENSEARCH_PREFIX_KEY.length()), entry.getValue());
+        }
+
+        if (throwable instanceof OpenSearchException) {
+            OpenSearchException exception = (OpenSearchException) throwable;
+            exception.metadataToXContent(builder, params);
+        }
+
+        if (params.paramAsBoolean(REST_EXCEPTION_SKIP_CAUSE, REST_EXCEPTION_SKIP_CAUSE_DEFAULT) == false) {
+            if (cause != null) {
+                builder.field(CAUSED_BY);
+                builder.startObject();
+                generateThrowableXContent(builder, params, cause);
+                builder.endObject();
+            }
+        }
+
+        if (headers.isEmpty() == false) {
+            builder.startObject(HEADER);
+            for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
+                headerToXContent(builder, entry.getKey(), entry.getValue());
+            }
+            builder.endObject();
+        }
+
+        if (params.paramAsBoolean(REST_EXCEPTION_SKIP_STACK_TRACE, REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT) == false) {
+            builder.field(STACK_TRACE, ExceptionsHelper.stackTrace(throwable));
+        }
+
+        Throwable[] allSuppressed = throwable.getSuppressed();
+        if (allSuppressed.length > 0) {
+            builder.startArray(SUPPRESSED.getPreferredName());
+            for (Throwable suppressed : allSuppressed) {
+                builder.startObject();
+                generateThrowableXContent(builder, params, suppressed);
+                builder.endObject();
+            }
+            builder.endArray();
+        }
+    }
+
+    protected static void headerToXContent(XContentBuilder builder, String key, List<String> values) throws IOException {
+        if (values != null && values.isEmpty() == false) {
+            if (values.size() == 1) {
+                builder.field(key, values.get(0));
+            } else {
+                builder.startArray(key);
+                for (String value : values) {
+                    builder.value(value);
+                }
+                builder.endArray();
+            }
+        }
+    }
+
+    /**
+     * Renders additional per exception information into the XContent
+     */
+    protected void metadataToXContent(XContentBuilder builder, Params params) throws IOException {}
+
+    /**
+     * Generate a {@link OpenSearchException} from a {@link XContentParser}. This does not
+     * return the original exception type (ie NodeClosedException for example) but just wraps
+     * the type, the reason and the cause of the exception. It also recursively parses the
+     * tree structure of the cause, returning it as a tree structure of {@link OpenSearchException}
+     * instances.
+     */
+    public static OpenSearchException fromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token = parser.nextToken();
+        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
+        return innerFromXContent(parser, false);
+    }
+
+    public static OpenSearchException innerFromXContent(XContentParser parser, boolean parseRootCauses) throws IOException {
+        XContentParser.Token token = parser.currentToken();
+        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
+
+        String type = null, reason = null, stack = null;
+        OpenSearchException cause = null;
+        Map<String, List<String>> metadata = new HashMap<>();
+        Map<String, List<String>> headers = new HashMap<>();
+        List<OpenSearchException> rootCauses = new ArrayList<>();
+        List<OpenSearchException> suppressed = new ArrayList<>();
+
+        for (; token == XContentParser.Token.FIELD_NAME; token = parser.nextToken()) {
+            String currentFieldName = parser.currentName();
+            token = parser.nextToken();
+
+            if (token.isValue()) {
+                if (TYPE.equals(currentFieldName)) {
+                    type = parser.text();
+                } else if (REASON.equals(currentFieldName)) {
+                    reason = parser.text();
+                } else if (STACK_TRACE.equals(currentFieldName)) {
+                    stack = parser.text();
+                } else if (token == XContentParser.Token.VALUE_STRING) {
+                    metadata.put(currentFieldName, Collections.singletonList(parser.text()));
+                }
+            } else if (token == XContentParser.Token.START_OBJECT) {
+                if (CAUSED_BY.equals(currentFieldName)) {
+                    cause = fromXContent(parser);
+                } else if (HEADER.equals(currentFieldName)) {
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            currentFieldName = parser.currentName();
+                        } else {
+                            List<String> values = headers.getOrDefault(currentFieldName, new ArrayList<>());
+                            if (token == XContentParser.Token.VALUE_STRING) {
+                                values.add(parser.text());
+                            } else if (token == XContentParser.Token.START_ARRAY) {
+                                while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                                    if (token == XContentParser.Token.VALUE_STRING) {
+                                        values.add(parser.text());
+                                    } else {
+                                        parser.skipChildren();
+                                    }
+                                }
+                            } else if (token == XContentParser.Token.START_OBJECT) {
+                                parser.skipChildren();
+                            }
+                            headers.put(currentFieldName, values);
+                        }
+                    }
+                } else {
+                    // Any additional metadata object added by the metadataToXContent method is ignored
+                    // and skipped, so that the parser does not fail on unknown fields. The parser only
+                    // support metadata key-pairs and metadata arrays of values.
+                    parser.skipChildren();
+                }
+            } else if (token == XContentParser.Token.START_ARRAY) {
+                if (parseRootCauses && ROOT_CAUSE.equals(currentFieldName)) {
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        rootCauses.add(fromXContent(parser));
+                    }
+                } else if (SUPPRESSED.match(currentFieldName, parser.getDeprecationHandler())) {
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        suppressed.add(fromXContent(parser));
+                    }
+                } else {
+                    // Parse the array and add each item to the corresponding list of metadata.
+                    // Arrays of objects are not supported yet and just ignored and skipped.
+                    List<String> values = new ArrayList<>();
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        if (token == XContentParser.Token.VALUE_STRING) {
+                            values.add(parser.text());
+                        } else {
+                            parser.skipChildren();
+                        }
+                    }
+                    if (values.size() > 0) {
+                        if (metadata.containsKey(currentFieldName)) {
+                            values.addAll(metadata.get(currentFieldName));
+                        }
+                        metadata.put(currentFieldName, values);
+                    }
+                }
+            }
+        }
+
+        OpenSearchException e = new OpenSearchException(buildMessage(type, reason, stack), cause) {
+        };
+        for (Map.Entry<String, List<String>> entry : metadata.entrySet()) {
+            // subclasses can print out additional metadata through the metadataToXContent method. Simple key-value pairs will be
+            // parsed back and become part of this metadata set, while objects and arrays are not supported when parsing back.
+            // Those key-value pairs become part of the metadata set and inherit the "opensearch." prefix as that is currently required
+            // by addMetadata. The prefix will get stripped out when printing metadata out so it will be effectively invisible.
+            // TODO move subclasses that print out simple metadata to using addMetadata directly and support also numbers and booleans.
+            // TODO rename metadataToXContent and have only SearchPhaseExecutionException use it, which prints out complex objects
+            e.addMetadata(OPENSEARCH_PREFIX_KEY + entry.getKey(), entry.getValue());
+        }
+        for (Map.Entry<String, List<String>> header : headers.entrySet()) {
+            e.addHeader(header.getKey(), header.getValue());
+        }
+
+        // Adds root causes as suppressed exception. This way they are not lost
+        // after parsing and can be retrieved using getSuppressed() method.
+        for (OpenSearchException rootCause : rootCauses) {
+            e.addSuppressed(rootCause);
+        }
+        for (OpenSearchException s : suppressed) {
+            e.addSuppressed(s);
+        }
+        return e;
+    }
+
+    /**
+     * Static toXContent helper method that renders {@link OpenSearchException} or {@link Throwable} instances
+     * as XContent, delegating the rendering to {@link OpenSearchException#toXContent(XContentBuilder, ToXContent.Params)}
+     * or {@link #innerToXContent(XContentBuilder, ToXContent.Params, Throwable, String, String, Map, Map, Throwable)}.
+     *
+     * This method is usually used when the {@link Throwable} is rendered as a part of another XContent object, and its result can
+     * be parsed back using the {@code OpenSearchException.fromXContent(XContentParser)} method.
+     */
+    public static void generateThrowableXContent(XContentBuilder builder, ToXContent.Params params, Throwable t) throws IOException {
+        t = ExceptionsHelper.unwrapCause(t);
+
+        if (t instanceof OpenSearchException) {
+            ((OpenSearchException) t).toXContent(builder, params);
+        } else {
+            innerToXContent(builder, params, t, getExceptionName(t), t.getMessage(), emptyMap(), emptyMap(), t.getCause());
+        }
+    }
+
+    /**
+     * Render any exception as a xcontent, encapsulated within a field or object named "error". The level of details that are rendered
+     * depends on the value of the "detailed" parameter: when it's false only a simple message based on the type and message of the
+     * exception is rendered. When it's true all detail are provided including guesses root causes, cause and potentially stack
+     * trace.
+     *
+     * This method is usually used when the {@link Exception} is rendered as a full XContent object, and its output can be parsed
+     * by the {@code #OpenSearchException.failureFromXContent(XContentParser)} method.
+     */
+    public static void generateFailureXContent(XContentBuilder builder, ToXContent.Params params, @Nullable Exception e, boolean detailed)
+        throws IOException {
+        // No exception to render as an error
+        if (e == null) {
+            builder.field(ERROR, "unknown");
+            return;
+        }
+
+        // Render the exception with a simple message
+        if (detailed == false) {
+            Throwable t = e;
+            for (int counter = 0; counter < 10 && t != null; counter++) {
+                if (t instanceof OpenSearchException) {
+                    break;
+                }
+                t = t.getCause();
+            }
+            builder.field(ERROR, ExceptionsHelper.summaryMessage(t != null ? t : e));
+            return;
+        }
+
+        // Render the exception with all details
+        final OpenSearchException[] rootCauses = OpenSearchException.guessRootCauses(e);
+        builder.startObject(ERROR);
+        {
+            builder.startArray(ROOT_CAUSE);
+            for (OpenSearchException rootCause : rootCauses) {
+                builder.startObject();
+                rootCause.toXContent(builder, new ToXContent.DelegatingMapParams(singletonMap(REST_EXCEPTION_SKIP_CAUSE, "true"), params));
+                builder.endObject();
+            }
+            builder.endArray();
+        }
+        generateThrowableXContent(builder, params, e);
+        builder.endObject();
+    }
+
+    /**
+     * Parses the output of {@link #generateFailureXContent(XContentBuilder, Params, Exception, boolean)}
+     */
+    public static OpenSearchException failureFromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token = parser.currentToken();
+        ensureFieldName(parser, token, ERROR);
+
+        token = parser.nextToken();
+        if (token.isValue()) {
+            return new OpenSearchException(buildMessage("exception", parser.text(), null)) {
+            };
+        }
+
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, token, parser);
+        token = parser.nextToken();
+
+        // Root causes are parsed in the innerFromXContent() and are added as suppressed exceptions.
+        return innerFromXContent(parser, true);
+    }
+
+    /**
+     * Returns the root cause of this exception or multiple if different shards caused different exceptions
+     */
+    public OpenSearchException[] guessRootCauses() {
+        final Throwable cause = getCause();
+        if (cause != null && cause instanceof OpenSearchException) {
+            return ((OpenSearchException) cause).guessRootCauses();
+        }
+        return new OpenSearchException[] { this };
+    }
+
+    /**
+     * Returns the root cause of this exception or multiple if different shards caused different exceptions.
+     * If the given exception is not an instance of {@link OpenSearchException} an empty array
+     * is returned.
+     */
+    public static OpenSearchException[] guessRootCauses(Throwable t) {
+        Throwable ex = ExceptionsHelper.unwrapCause(t);
+        if (ex instanceof OpenSearchException) {
+            // OpenSearchException knows how to guess its own root cause
+            return ((OpenSearchException) ex).guessRootCauses();
+        }
+        if (ex instanceof XContentParseException) {
+            /*
+             * We'd like to unwrap parsing exceptions to the inner-most
+             * parsing exception because that is generally the most interesting
+             * exception to return to the user. If that exception is caused by
+             * an OpenSearchException we'd like to keep unwrapping because
+             * OpenSearchException instances tend to contain useful information
+             * for the user.
+             */
+            Throwable cause = ex.getCause();
+            if (cause != null) {
+                if (cause instanceof XContentParseException || cause instanceof OpenSearchException) {
+                    return OpenSearchException.guessRootCauses(ex.getCause());
+                }
+            }
+        }
+        return new OpenSearchException[] { new OpenSearchException(ex.getMessage(), ex) {
+            @Override
+            protected String getExceptionName() {
+                return getExceptionName(getCause());
+            }
+        } };
+    }
+
+    protected String getExceptionName() {
+        return getExceptionName(this);
+    }
+
+    /**
+     * Returns an underscore case name for the given exception. This method strips {@code OpenSearch} prefixes from exception names.
+     */
+    public static String getExceptionName(Throwable ex) {
+        String simpleName = getExceptionSimpleClassName(ex);
+        if (simpleName.startsWith("OpenSearch")) {
+            simpleName = simpleName.substring("OpenSearch".length());
+        }
+        // TODO: do we really need to make the exception name in underscore casing?
+        return toUnderscoreCase(simpleName);
+    }
+
+    public static String getExceptionSimpleClassName(final Throwable ex) {
+        String simpleName = ex.getClass().getSimpleName();
+        if (Strings.isEmpty(simpleName)) {
+            simpleName = "OpenSearchException";
+        }
+        return simpleName;
+    }
+
+    static String buildMessage(String type, String reason, String stack) {
+        StringBuilder message = new StringBuilder("OpenSearch exception [");
+        message.append(TYPE).append('=').append(type).append(", ");
+        message.append(REASON).append('=').append(reason);
+        if (stack != null) {
+            message.append(", ").append(STACK_TRACE).append('=').append(stack);
+        }
+        message.append(']');
+        return message.toString();
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        if (metadata.containsKey(INDEX_METADATA_KEY)) {
+            builder.append(getIndex());
+            if (metadata.containsKey(SHARD_METADATA_KEY)) {
+                builder.append('[').append(getShardId()).append(']');
+            }
+            builder.append(' ');
+        }
+        return builder.append(ExceptionsHelper.detailedMessage(this).trim()).toString();
+    }
+
+    /**
+     * Deserializes stacktrace elements as well as suppressed exceptions from the given output stream and
+     * adds it to the given exception.
+     */
+    public static <T extends Throwable> T readStackTrace(T throwable, StreamInput in) throws IOException {
+        throwable.setStackTrace(in.readArray(i -> {
+            final String declaringClasss = i.readString();
+            final String fileName = i.readOptionalString();
+            final String methodName = i.readString();
+            final int lineNumber = i.readVInt();
+            return new StackTraceElement(declaringClasss, methodName, fileName, lineNumber);
+        }, StackTraceElement[]::new));
+
+        int numSuppressed = in.readVInt();
+        for (int i = 0; i < numSuppressed; i++) {
+            throwable.addSuppressed(in.readException());
+        }
+        return throwable;
+    }
+
+    /**
+     * Serializes the given exceptions stacktrace elements as well as it's suppressed exceptions to the given output stream.
+     */
+    public static <S extends StreamOutput, T extends Throwable> T writeStackTraces(
+        T throwable,
+        StreamOutput out,
+        Writer<Throwable> exceptionWriter
+    ) throws IOException {
+        out.writeArray((o, v) -> {
+            o.writeString(v.getClassName());
+            o.writeOptionalString(v.getFileName());
+            o.writeString(v.getMethodName());
+            o.writeVInt(v.getLineNumber());
+        }, throwable.getStackTrace());
+        out.writeArray(exceptionWriter, throwable.getSuppressed());
+        return throwable;
+    }
+
+    public void setResources(String type, String... id) {
+        assert type != null;
+        addMetadata(RESOURCE_METADATA_ID_KEY, id);
+        addMetadata(RESOURCE_METADATA_TYPE_KEY, type);
+    }
+
+    public List<String> getResourceId() {
+        return getMetadata(RESOURCE_METADATA_ID_KEY);
+    }
+
+    public String getResourceType() {
+        List<String> header = getMetadata(RESOURCE_METADATA_TYPE_KEY);
+        if (header != null && header.isEmpty() == false) {
+            assert header.size() == 1;
+            return header.get(0);
+        }
+        return null;
+    }
+
+    // lower cases and adds underscores to transitions in a name
+    private static String toUnderscoreCase(String value) {
+        StringBuilder sb = new StringBuilder();
+        boolean changed = false;
+        for (int i = 0; i < value.length(); i++) {
+            char c = value.charAt(i);
+            if (Character.isUpperCase(c)) {
+                if (!changed) {
+                    // copy it over here
+                    for (int j = 0; j < i; j++) {
+                        sb.append(value.charAt(j));
+                    }
+                    changed = true;
+                    if (i == 0) {
+                        sb.append(Character.toLowerCase(c));
+                    } else {
+                        sb.append('_');
+                        sb.append(Character.toLowerCase(c));
+                    }
+                } else {
+                    sb.append('_');
+                    sb.append(Character.toLowerCase(c));
+                }
+            } else {
+                if (changed) {
+                    sb.append(c);
+                }
+            }
+        }
+        if (!changed) {
+            return value;
+        }
+        return sb.toString();
+    }
+
+    /**
+     * Returns an array of all registered handle IDs. These are the IDs for every registered
+     * exception.
+     *
+     * @return an array of all registered handle IDs
+     */
+    static int[] ids() {
+        return OpenSearchExceptionHandleRegistry.ids().stream().mapToInt(i -> i).toArray();
+    }
+
+    /**
+     * Returns an array of all registered pairs of handle IDs and exception classes. These pairs are
+     * provided for every registered exception.
+     *
+     * @return an array of all registered pairs of handle IDs and exception classes
+     */
+    @SuppressWarnings("unchecked")
+    static Tuple<Integer, Class<? extends OpenSearchException>>[] classes() {
+        final Tuple<Integer, Class<? extends OpenSearchException>>[] ts = OpenSearchExceptionHandleRegistry.handles()
+            .stream()
+            .map(h -> Tuple.tuple(h.id, h.exceptionClass))
+            .toArray(Tuple[]::new);
+        return ts;
+    }
+
+    public Index getIndex() {
+        List<String> index = getMetadata(INDEX_METADATA_KEY);
+        if (index != null && index.isEmpty() == false) {
+            List<String> index_uuid = getMetadata(INDEX_METADATA_KEY_UUID);
+            return new Index(index.get(0), index_uuid.get(0));
+        }
+
+        return null;
+    }
+
+    public void setIndex(Index index) {
+        if (index != null) {
+            addMetadata(INDEX_METADATA_KEY, index.getName());
+            addMetadata(INDEX_METADATA_KEY_UUID, index.getUUID());
+        }
+    }
+
+    public void setIndex(String index) {
+        if (index != null) {
+            setIndex(new Index(index, Strings.UNKNOWN_UUID_VALUE));
+        }
+    }
+
+    public ShardId getShardId() {
+        List<String> shard = getMetadata(SHARD_METADATA_KEY);
+        if (shard != null && shard.isEmpty() == false) {
+            return new ShardId(getIndex(), Integer.parseInt(shard.get(0)));
+        }
+        return null;
+    }
+
+    public void setShard(ShardId shardId) {
+        if (shardId != null) {
+            setIndex(shardId.getIndex());
+            addMetadata(SHARD_METADATA_KEY, Integer.toString(shardId.id()));
+        }
+    }
+
+    /**
+     * This is the list of Exceptions OpenSearch can throw over the wire or save into a corruption marker. Each value in the enum is a
+     * single exception tying the Class to an id for use of the encode side and the id back to a constructor for use on the decode side. As
+     * such its ok if the exceptions to change names so long as their constructor can still read the exception. Each exception is listed
+     * in id order. If you want to remove an exception leave a tombstone comment and mark the id as null in
+     * ExceptionSerializationTests.testIds.ids.
+     *
+     * @opensearch.internal
+     */
+    protected static class OpenSearchExceptionHandle {
+        final Class<? extends OpenSearchException> exceptionClass;
+        final CheckedFunction<StreamInput, ? extends OpenSearchException, IOException> constructor;
+        final int id;
+        final Version versionAdded;
+
+        <E extends OpenSearchException> OpenSearchExceptionHandle(
+            Class<E> exceptionClass,
+            CheckedFunction<StreamInput, E, IOException> constructor,
+            int id,
+            Version versionAdded
+        ) {
+            // We need the exceptionClass because you can't dig it out of the constructor reliably.
+            this.exceptionClass = exceptionClass;
+            this.constructor = constructor;
+            this.versionAdded = versionAdded;
+            this.id = id;
+        }
+    }
+
+    /**
+     * Registry of ExceptionHandlers
+     *
+     * @opensearch.internal
+     */
+    public static class OpenSearchExceptionHandleRegistry {
+        /** Registry mapping from unique Ordinal to the Exception Constructor */
+        private static final Map<
+            Integer,
+            CheckedFunction<StreamInput, ? extends OpenSearchException, IOException>> ID_TO_SUPPLIER_REGISTRY = new ConcurrentHashMap<>();
+        /** Registry mapping from Exception class to the Exception Handler  */
+        private static final Map<
+            Class<? extends OpenSearchException>,
+            OpenSearchExceptionHandle> CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY = new ConcurrentHashMap<>();
+
+        /** returns the Exception constructor function from a given ordinal */
+        public static CheckedFunction<StreamInput, ? extends OpenSearchException, IOException> getSupplier(final int id) {
+            return ID_TO_SUPPLIER_REGISTRY.get(id);
+        }
+
+        /** registers the Exception handler */
+        public static void registerExceptionHandle(final OpenSearchExceptionHandle handle) {
+            ID_TO_SUPPLIER_REGISTRY.put(handle.id, handle.constructor);
+            CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY.put(handle.exceptionClass, handle);
+        }
+
+        /** Gets the unique ordinal id of the Exception from the given class */
+        public static int getId(final Class<? extends OpenSearchException> exception) {
+            return CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY.get(exception).id;
+        }
+
+        /** returns a set of ids */
+        public static Set<Integer> ids() {
+            return ID_TO_SUPPLIER_REGISTRY.keySet();
+        }
+
+        /** returns a collection of handles */
+        public static Collection<OpenSearchExceptionHandle> handles() {
+            return CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY.values();
+        }
+
+        /** checks that the exception class is registered */
+        public static boolean isRegistered(final Class<? extends Throwable> exception, final Version version) {
+            OpenSearchExceptionHandle openSearchExceptionHandle = CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY.get(exception);
+            if (openSearchExceptionHandle != null) {
+                return version.onOrAfter(openSearchExceptionHandle.versionAdded);
+            }
+            return false;
+        }
+
+        /** returns a set of registered exception classes */
+        public static Set<Class<? extends OpenSearchException>> getRegisteredKeys() { // for testing
+            return CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE_REGISTRY.keySet();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/OpenSearchParseException.java b/libs/core/src/main/java/org/opensearch/OpenSearchParseException.java
similarity index 93%
rename from server/src/main/java/org/opensearch/OpenSearchParseException.java
rename to libs/core/src/main/java/org/opensearch/OpenSearchParseException.java
index 0cc537f36a3ec..c2516402b0d30 100644
--- a/server/src/main/java/org/opensearch/OpenSearchParseException.java
+++ b/libs/core/src/main/java/org/opensearch/OpenSearchParseException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Unchecked exception that is translated into a {@code 400 BAD REQUEST} error when it bubbles out over HTTP.
+ *
+ * @opensearch.internal
  */
 public class OpenSearchParseException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/OpenSearchWrapperException.java b/libs/core/src/main/java/org/opensearch/OpenSearchWrapperException.java
similarity index 98%
rename from server/src/main/java/org/opensearch/OpenSearchWrapperException.java
rename to libs/core/src/main/java/org/opensearch/OpenSearchWrapperException.java
index aa3e857f96901..3ef5ec4feac2d 100644
--- a/server/src/main/java/org/opensearch/OpenSearchWrapperException.java
+++ b/libs/core/src/main/java/org/opensearch/OpenSearchWrapperException.java
@@ -36,6 +36,8 @@
  * An exception that is meant to be "unwrapped" when sent back to the user
  * as an error because its is {@link #getCause() cause}, if non-null is
  * <strong>always</strong> more useful to the user than the exception itself.
+ *
+ * @opensearch.internal
  */
 public interface OpenSearchWrapperException {
     Throwable getCause();
diff --git a/server/src/main/java/org/opensearch/Version.java b/libs/core/src/main/java/org/opensearch/Version.java
similarity index 76%
rename from server/src/main/java/org/opensearch/Version.java
rename to libs/core/src/main/java/org/opensearch/Version.java
index f74e529c442bb..7b8d9e468c845 100644
--- a/server/src/main/java/org/opensearch/Version.java
+++ b/libs/core/src/main/java/org/opensearch/Version.java
@@ -32,15 +32,10 @@
 
 package org.opensearch;
 
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.monitor.jvm.JvmInfo;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.lang.reflect.Field;
@@ -51,6 +46,12 @@
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * OpenSearch Version Class
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class Version implements Comparable<Version>, ToXContentFragment {
     /*
      * The logic for ID is: XXYYZZAA, where XX is major version, YY is minor version, ZZ is revision, and AA is alpha/beta/rc indicator AA
@@ -80,13 +81,45 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_1_2_5 = new Version(1020599, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_1_3_0 = new Version(1030099, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_1_3_1 = new Version(1030199, org.apache.lucene.util.Version.LUCENE_8_10_1);
-    public static final Version V_1_4_0 = new Version(1040099, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_2 = new Version(1030299, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_3 = new Version(1030399, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_4 = new Version(1030499, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_5 = new Version(1030599, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_6 = new Version(1030699, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_7 = new Version(1030799, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_8 = new Version(1030899, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_9 = new Version(1030999, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_10 = new Version(1031099, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_11 = new Version(1031199, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_12 = new Version(1031299, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_13 = new Version(1031399, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_14 = new Version(1031499, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_2_0_0 = new Version(2000099, org.apache.lucene.util.Version.LUCENE_9_1_0);
-    public static final Version CURRENT = V_2_0_0;
-
-    public static Version readVersion(StreamInput in) throws IOException {
-        return fromId(in.readVInt());
-    }
+    public static final Version V_2_0_1 = new Version(2000199, org.apache.lucene.util.Version.LUCENE_9_1_0);
+    public static final Version V_2_0_2 = new Version(2000299, org.apache.lucene.util.Version.LUCENE_9_1_0);
+    public static final Version V_2_1_0 = new Version(2010099, org.apache.lucene.util.Version.LUCENE_9_2_0);
+    public static final Version V_2_1_1 = new Version(2010199, org.apache.lucene.util.Version.LUCENE_9_2_0);
+    public static final Version V_2_2_0 = new Version(2020099, org.apache.lucene.util.Version.LUCENE_9_3_0);
+    public static final Version V_2_2_1 = new Version(2020199, org.apache.lucene.util.Version.LUCENE_9_3_0);
+    public static final Version V_2_2_2 = new Version(2020299, org.apache.lucene.util.Version.LUCENE_9_3_0);
+    public static final Version V_2_3_0 = new Version(2030099, org.apache.lucene.util.Version.LUCENE_9_3_0);
+    public static final Version V_2_3_1 = new Version(2030199, org.apache.lucene.util.Version.LUCENE_9_3_0);
+    public static final Version V_2_4_0 = new Version(2040099, org.apache.lucene.util.Version.LUCENE_9_4_1);
+    public static final Version V_2_4_1 = new Version(2040199, org.apache.lucene.util.Version.LUCENE_9_4_2);
+    public static final Version V_2_4_2 = new Version(2040299, org.apache.lucene.util.Version.LUCENE_9_4_2);
+    public static final Version V_2_5_0 = new Version(2050099, org.apache.lucene.util.Version.LUCENE_9_4_2);
+    public static final Version V_2_5_1 = new Version(2050199, org.apache.lucene.util.Version.LUCENE_9_4_2);
+    public static final Version V_2_6_0 = new Version(2060099, org.apache.lucene.util.Version.LUCENE_9_5_0);
+    public static final Version V_2_6_1 = new Version(2060199, org.apache.lucene.util.Version.LUCENE_9_5_0);
+    public static final Version V_2_7_0 = new Version(2070099, org.apache.lucene.util.Version.LUCENE_9_5_0);
+    public static final Version V_2_7_1 = new Version(2070199, org.apache.lucene.util.Version.LUCENE_9_5_0);
+    public static final Version V_2_8_0 = new Version(2080099, org.apache.lucene.util.Version.LUCENE_9_6_0);
+    public static final Version V_2_8_1 = new Version(2080199, org.apache.lucene.util.Version.LUCENE_9_6_0);
+    public static final Version V_2_9_0 = new Version(2090099, org.apache.lucene.util.Version.LUCENE_9_7_0);
+    public static final Version V_2_9_1 = new Version(2090199, org.apache.lucene.util.Version.LUCENE_9_7_0);
+    public static final Version V_2_10_0 = new Version(2100099, org.apache.lucene.util.Version.LUCENE_9_7_0);
+    public static final Version V_2_11_0 = new Version(2110099, org.apache.lucene.util.Version.LUCENE_9_7_0);
+    public static final Version CURRENT = V_2_11_0;
 
     public static Version fromId(int id) {
         final Version known = LegacyESVersion.idToVersion.get(id);
@@ -124,30 +157,6 @@ private static Version fromIdSlow(int id) {
         return id < MASK ? new LegacyESVersion(id, luceneVersion) : new Version(id ^ MASK, luceneVersion);
     }
 
-    /**
-     * Return the {@link Version} of OpenSearch that has been used to create an index given its settings.
-     *
-     * @throws IllegalStateException if the given index settings doesn't contain a value for the key
-     *         {@value IndexMetadata#SETTING_VERSION_CREATED}
-     */
-    public static Version indexCreated(Settings indexSettings) {
-        final Version indexVersion = IndexMetadata.SETTING_INDEX_VERSION_CREATED.get(indexSettings);
-        if (indexVersion.equals(V_EMPTY)) {
-            final String message = String.format(
-                Locale.ROOT,
-                "[%s] is not present in the index settings for index with UUID [%s]",
-                IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(),
-                indexSettings.get(IndexMetadata.SETTING_INDEX_UUID)
-            );
-            throw new IllegalStateException(message);
-        }
-        return indexVersion;
-    }
-
-    public static void writeVersion(Version version, StreamOutput out) throws IOException {
-        out.writeVInt(version.id);
-    }
-
     public static int computeLegacyID(int major, int minor, int revision, int build) {
         return major * 1000000 + minor * 10000 + revision * 100 + build;
     }
@@ -174,7 +183,7 @@ public static Version max(Version version1, Version version2) {
      * Returns the version given its string representation, current version if the argument is null or empty
      */
     public static Version fromString(String version) {
-        if (!Strings.hasLength(version)) {
+        if (stringHasLength(version) == false) { // TODO replace with Strings.hasLength after refactoring Strings to core lib
             return Version.CURRENT;
         }
         final Version cached = LegacyESVersion.stringToVersion.get(version);
@@ -278,11 +287,16 @@ public boolean onOrBefore(Version version) {
         return version.id >= id;
     }
 
-    // LegacyESVersion major 7 is equivalent to Version major 1
     public int compareMajor(Version other) {
-        int m = major == 1 ? 7 : major == 2 ? 8 : major;
-        int om = other.major == 1 ? 7 : other.major == 2 ? 8 : other.major;
-        return Integer.compare(m, om);
+        // comparing Legacy 7x for bwc
+        // todo: remove the following when removing legacy support in 3.0.0
+        if (major == 7 || other.major == 7 || major == 6 || other.major == 6) {
+            // opensearch v1.x and v2.x need major translation to compare w/ legacy versions
+            int m = major == 1 ? 7 : major == 2 ? 8 : major;
+            int om = other.major == 1 ? 7 : other.major == 2 ? 8 : other.major;
+            return Integer.compare(m, om);
+        }
+        return Integer.compare(major, other.major);
     }
 
     @Override
@@ -338,12 +352,9 @@ protected Version computeMinCompatVersion() {
         } else if (major == 6) {
             // force the minimum compatibility for version 6 to 5.6 since we don't reference version 5 anymore
             return LegacyESVersion.fromId(5060099);
-        }
-        /*
-         * TODO - uncomment this logic from OpenSearch version 3 onwards
-         *
-        else if (major >= 3) {
+        } else if (major >= 3 && major < 5) {
             // all major versions from 3 onwards are compatible with last minor series of the previous major
+            // todo: remove 5 check when removing LegacyESVersionTests
             Version bwcVersion = null;
 
             for (int i = DeclaredVersionsHolder.DECLARED_VERSIONS.size() - 1; i >= 0; i--) {
@@ -357,7 +368,6 @@ else if (major >= 3) {
             }
             return bwcVersion == null ? this : bwcVersion;
         }
-         */
 
         return Version.min(this, fromId(maskId((int) major * 1000000 + 0 * 10000 + 99)));
     }
@@ -395,6 +405,10 @@ private Version computeMinIndexCompatVersion() {
             bwcMajor = major - 1;
         }
         final int bwcMinor = 0;
+        if (major == 3) {
+            return Version.min(this, fromId((bwcMajor * 1000000 + bwcMinor * 10000 + 99) ^ MASK));
+        }
+        // todo remove below when LegacyESVersion is removed in 3.0
         return Version.min(this, fromId((bwcMajor * 1000000 + bwcMinor * 10000 + 99)));
     }
 
@@ -408,16 +422,15 @@ public boolean isCompatible(Version version) {
         // OpenSearch version 2 is the functional equivalent of predecessor unreleased version "8"
         // todo refactor this logic after removing deprecated features
         int a = major;
-        if (major == 1) {
-            a = 7;
-        } else if (major == 2) {
-            a = 8;
-        }
         int b = version.major;
-        if (version.major == 1) {
-            b = 7;
-        } else if (version.major == 2) {
-            b = 8;
+
+        if (a == 7 || b == 7 || a == 6 || b == 6) {
+            if (major <= 2) {
+                a += 6; // for legacy compatibility up to version 2.x (to compare minCompat)
+            }
+            if (version.major <= 2) {
+                b += 6; // for legacy compatibility up to version 2.x (to compare minCompat)
+            }
         }
 
         assert compatible == false || Math.max(a, b) - Math.min(a, b) <= 1;
@@ -433,7 +446,7 @@ public static void main(String[] args) {
             Build.CURRENT.type().displayName(),
             Build.CURRENT.hash(),
             Build.CURRENT.date(),
-            JvmInfo.jvmInfo().version()
+            System.getProperty("java.version")  // TODO switch back to JvmInfo.jvmInfo().version() after refactoring to core lib
         );
         System.out.println(versionOutput);
     }
@@ -530,4 +543,12 @@ public static List<Version> getDeclaredVersions(final Class<?> versionClass) {
         Collections.sort(versions);
         return versions;
     }
+
+    /**
+     * Check that the given String is neither <code>null</code> nor of length 0.
+     * Note: Will return <code>true</code> for a String that purely consists of whitespace.
+     */
+    public static boolean stringHasLength(String str) {
+        return (str != null && str.length() > 0);
+    }
 }
diff --git a/libs/core/src/main/java/org/opensearch/bootstrap/JavaVersion.java b/libs/core/src/main/java/org/opensearch/bootstrap/JavaVersion.java
deleted file mode 100644
index 236563bf8bd89..0000000000000
--- a/libs/core/src/main/java/org/opensearch/bootstrap/JavaVersion.java
+++ /dev/null
@@ -1,146 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.bootstrap;
-
-import java.math.BigInteger;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
-
-public class JavaVersion implements Comparable<JavaVersion> {
-
-    private final List<Integer> version;
-    private final String prePart;
-
-    public List<Integer> getVersion() {
-        return version;
-    }
-
-    private JavaVersion(List<Integer> version, String prePart) {
-        this.prePart = prePart;
-        if (version.size() >= 2 && version.get(0) == 1 && version.get(1) == 8) {
-            // for Java 8 there is ambiguity since both 1.8 and 8 are supported,
-            // so we rewrite the former to the latter
-            version = new ArrayList<>(version.subList(1, version.size()));
-        }
-        this.version = Collections.unmodifiableList(version);
-    }
-
-    /**
-     * Parses the Java version as it can be retrieved as the value of java.version or
-     * java.specification.version according to JEP 223.
-     *
-     * @param value The version String
-     */
-    public static JavaVersion parse(String value) {
-        Objects.requireNonNull(value);
-        String prePart = null;
-        if (!isValid(value)) {
-            throw new IllegalArgumentException("Java version string [" + value + "] could not be parsed.");
-        }
-        List<Integer> version = new ArrayList<>();
-        String[] parts = value.split("-");
-        String[] numericComponents;
-        if (parts.length == 1) {
-            numericComponents = value.split("\\.");
-        } else if (parts.length == 2) {
-            numericComponents = parts[0].split("\\.");
-            prePart = parts[1];
-        } else {
-            throw new IllegalArgumentException("Java version string [" + value + "] could not be parsed.");
-        }
-
-        for (String component : numericComponents) {
-            version.add(Integer.valueOf(component));
-        }
-        return new JavaVersion(version, prePart);
-    }
-
-    public static boolean isValid(String value) {
-        return value.matches("^0*[0-9]+(\\.[0-9]+)*(-[a-zA-Z0-9]+)?$");
-    }
-
-    private static final JavaVersion CURRENT = parse(System.getProperty("java.specification.version"));
-
-    public static JavaVersion current() {
-        return CURRENT;
-    }
-
-    @Override
-    public int compareTo(JavaVersion o) {
-        int len = Math.max(version.size(), o.version.size());
-        for (int i = 0; i < len; i++) {
-            int d = (i < version.size() ? version.get(i) : 0);
-            int s = (i < o.version.size() ? o.version.get(i) : 0);
-            if (s < d) return 1;
-            if (s > d) return -1;
-        }
-        if (prePart != null && o.prePart == null) {
-            return -1;
-        } else if (prePart == null && o.prePart != null) {
-            return 1;
-        } else if (prePart != null && o.prePart != null) {
-            return comparePrePart(prePart, o.prePart);
-        }
-        return 0;
-    }
-
-    private int comparePrePart(String prePart, String otherPrePart) {
-        if (prePart.matches("\\d+")) {
-            return otherPrePart.matches("\\d+") ? (new BigInteger(prePart)).compareTo(new BigInteger(otherPrePart)) : -1;
-        } else {
-            return otherPrePart.matches("\\d+") ? 1 : prePart.compareTo(otherPrePart);
-        }
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (o == null || o.getClass() != getClass()) {
-            return false;
-        }
-        return compareTo((JavaVersion) o) == 0;
-    }
-
-    @Override
-    public int hashCode() {
-        return version.hashCode();
-    }
-
-    @Override
-    public String toString() {
-        final String versionString = version.stream().map(v -> Integer.toString(v)).collect(Collectors.joining("."));
-        return prePart != null ? versionString + "-" + prePart : versionString;
-    }
-}
diff --git a/libs/core/src/main/java/org/opensearch/common/collect/List.java b/libs/core/src/main/java/org/opensearch/common/collect/List.java
deleted file mode 100644
index 96bdacc276323..0000000000000
--- a/libs/core/src/main/java/org/opensearch/common/collect/List.java
+++ /dev/null
@@ -1,106 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-
-public class List {
-
-    /**
-     * Returns an unmodifiable list containing zero elements.
-     *
-     * @param <T> the {@code List}'s element type
-     * @return an empty {@code List}
-     */
-    public static <T> java.util.List<T> of() {
-        return Collections.emptyList();
-    }
-
-    /**
-     * Returns an unmodifiable list containing one element.
-     *
-     * @param <T> the {@code List}'s element type
-     * @param e1  the single element
-     * @return a {@code List} containing the specified element
-     */
-    public static <T> java.util.List<T> of(T e1) {
-        return Collections.singletonList(e1);
-    }
-
-    /**
-     * Returns an unmodifiable list containing two elements.
-     *
-     * @param <T> the {@code List}'s element type
-     * @param e1 the first element
-     * @param e2 the second element
-     * @return a {@code List} containing the specified element
-     */
-    @SuppressWarnings("unchecked")
-    public static <T> java.util.List<T> of(T e1, T e2) {
-        return List.of((T[]) new Object[] { e1, e2 });
-    }
-
-    /**
-     * Returns an unmodifiable list containing an arbitrary number of elements.
-     *
-     * @param entries the elements to be contained in the list
-     * @param <T>     the {@code List}'s element type
-     * @return an unmodifiable list containing the specified elements.
-     */
-    @SafeVarargs
-    @SuppressWarnings("varargs")
-    public static <T> java.util.List<T> of(T... entries) {
-        switch (entries.length) {
-            case 0:
-                return List.of();
-            case 1:
-                return List.of(entries[0]);
-            default:
-                return Collections.unmodifiableList(Arrays.asList(entries));
-        }
-    }
-
-    /**
-     * Returns an unmodifiable {@code List} containing the elements of the given {@code Collection} in iteration order.
-     *
-     * @param <T>  the {@code List}'s element type
-     * @param coll a {@code Collection} from which elements are drawn, must be non-null
-     * @return a {@code List} containing the elements of the given {@code Collection}
-     */
-    @SuppressWarnings("unchecked")
-    public static <T> java.util.List<T> copyOf(Collection<? extends T> coll) {
-        return (java.util.List<T>) List.of(coll.toArray());
-    }
-}
diff --git a/libs/core/src/main/java/org/opensearch/common/collect/Map.java b/libs/core/src/main/java/org/opensearch/common/collect/Map.java
deleted file mode 100644
index 3b401ee0e1c1b..0000000000000
--- a/libs/core/src/main/java/org/opensearch/common/collect/Map.java
+++ /dev/null
@@ -1,236 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.AbstractMap;
-import java.util.Collections;
-import java.util.HashMap;
-
-public class Map {
-
-    /**
-     * Returns an unmodifiable map containing one mapping.
-     */
-    public static <K, V> java.util.Map<K, V> of() {
-        return Collections.emptyMap();
-    }
-
-    /**
-     * Returns an unmodifiable map containing one mapping.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1) {
-        return Collections.singletonMap(k1, v1);
-    }
-
-    /**
-     * Returns an unmodifiable map containing two mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2) {
-        return mapN(k1, v1, k2, v2);
-    }
-
-    /**
-     * Returns an unmodifiable map containing three mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
-        return mapN(k1, v1, k2, v2, k3, v3);
-    }
-
-    /**
-     * Returns an unmodifiable map containing four mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4);
-    }
-
-    /**
-     * Returns an unmodifiable map containing five mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5);
-    }
-
-    /**
-     * Returns an unmodifiable map containing six mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6);
-    }
-
-    /**
-     * Returns an unmodifiable map containing seven mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7);
-    }
-
-    /**
-     * Returns an unmodifiable map containing eight mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8
-    ) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8);
-    }
-
-    /**
-     * Returns an unmodifiable map containing nine mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8,
-        K k9,
-        V v9
-    ) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9);
-    }
-
-    /**
-     * Returns an unmodifiable map containing ten mappings.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8,
-        K k9,
-        V v9,
-        K k10,
-        V v10
-    ) {
-        return mapN(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9, k10, v10);
-    }
-
-    @SuppressWarnings("unchecked")
-    private static <K, V> java.util.Map<K, V> mapN(Object... objects) {
-        if (objects.length % 2 != 0) {
-            throw new IllegalStateException("Must provide an even number of arguments to Map::of method");
-        }
-        switch (objects.length) {
-            case 0:
-                return Map.of();
-            case 2:
-                return Map.of((K) objects[0], (V) objects[1]);
-            default:
-                HashMap<K, V> map = new HashMap<>();
-                for (int k = 0; k < objects.length / 2; k++) {
-                    map.put((K) objects[k * 2], (V) objects[k * 2 + 1]);
-                }
-                return Collections.unmodifiableMap(map);
-        }
-    }
-
-    /**
-     * Returns an unmodifiable map containing keys and values extracted from the given entries.
-     *
-     * @param <K> the {@code Map}'s key type
-     * @param <V> the {@code Map}'s value type
-     * @param entries {@code Map.Entry}s containing the keys and values from which the map is populated
-     * @return a {@code Map} containing the specified mappings
-     */
-    @SafeVarargs
-    public static <K, V> java.util.Map<K, V> ofEntries(java.util.Map.Entry<? extends K, ? extends V>... entries) {
-        if (entries.length == 0) {
-            return Collections.emptyMap();
-        } else if (entries.length == 1) {
-            return Collections.singletonMap(entries[0].getKey(), entries[0].getValue());
-        } else {
-            HashMap<K, V> map = new HashMap<>();
-            for (java.util.Map.Entry<? extends K, ? extends V> entry : entries) {
-                map.put(entry.getKey(), entry.getValue());
-            }
-            return Collections.unmodifiableMap(map);
-        }
-    }
-
-    /**
-     * Returns an unmodifiable Map.Entry for the provided key and value.
-     */
-    public static <K, V> java.util.Map.Entry<K, V> entry(K k, V v) {
-        return new AbstractMap.SimpleImmutableEntry<>(k, v);
-    }
-
-    /**
-     * Returns an unmodifiable {@code Map} containing the entries of the given {@code Map}.
-     *
-     * @param <K> the {@code Map}'s key type
-     * @param <V> the {@code Map}'s value type
-     * @param map a {@code Map} from which entries are drawn, must be non-null
-     * @return a {@code Map} containing the entries of the given {@code Map}
-     */
-    @SuppressWarnings({ "unchecked", "rawtypes" })
-    public static <K, V> java.util.Map<K, V> copyOf(java.util.Map<? extends K, ? extends V> map) {
-        return (java.util.Map<K, V>) Map.ofEntries(map.entrySet().toArray(new java.util.Map.Entry[0]));
-    }
-}
diff --git a/libs/core/src/main/java/org/opensearch/common/collect/Set.java b/libs/core/src/main/java/org/opensearch/common/collect/Set.java
deleted file mode 100644
index 921408b88241f..0000000000000
--- a/libs/core/src/main/java/org/opensearch/common/collect/Set.java
+++ /dev/null
@@ -1,109 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashSet;
-
-public class Set {
-
-    /**
-     * Returns an unmodifiable set containing zero elements.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @return an empty {@code Set}
-     */
-    public static <T> java.util.Set<T> of() {
-        return Collections.emptySet();
-    }
-
-    /**
-     * Returns an unmodifiable set containing one element.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @param e1  the single element
-     * @return a {@code Set} containing the specified element
-     */
-    public static <T> java.util.Set<T> of(T e1) {
-        return Collections.singleton(e1);
-    }
-
-    /**
-     * Returns an unmodifiable set containing two elements.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @param e1 the first element
-     * @param e2 the second element
-     * @return a {@code Set} containing the specified element
-     */
-    @SuppressWarnings("unchecked")
-    public static <T> java.util.Set<T> of(T e1, T e2) {
-        return Set.of((T[]) new Object[] { e1, e2 });
-    }
-
-    /**
-     * Returns an unmodifiable set containing an arbitrary number of elements.
-     *
-     * @param entries the elements to be contained in the set
-     * @param <T>     the {@code Set}'s element type
-     * @return an unmodifiable set containing the specified elements.
-     */
-    @SafeVarargs
-    @SuppressWarnings("varargs")
-    public static <T> java.util.Set<T> of(T... entries) {
-        switch (entries.length) {
-            case 0:
-                return Set.of();
-            case 1:
-                return Set.of(entries[0]);
-            default:
-                return Collections.unmodifiableSet(new HashSet<>(Arrays.asList(entries)));
-        }
-    }
-
-    /**
-     * Returns an unmodifiable {@code Set} containing the elements of the given Collection.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @param coll a {@code Collection} from which elements are drawn, must be non-null
-     * @return a {@code Set} containing the elements of the given {@code Collection}
-     * @throws NullPointerException if coll is null, or if it contains any nulls
-     * @since 10
-     */
-    @SuppressWarnings("unchecked")
-    public static <T> java.util.Set<T> copyOf(Collection<? extends T> coll) {
-        return (java.util.Set<T>) Set.of(new HashSet<>(coll).toArray());
-    }
-}
diff --git a/libs/core/src/main/java/org/opensearch/common/collect/Tuple.java b/libs/core/src/main/java/org/opensearch/common/collect/Tuple.java
deleted file mode 100644
index cc82123056423..0000000000000
--- a/libs/core/src/main/java/org/opensearch/common/collect/Tuple.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-public class Tuple<V1, V2> {
-
-    public static <V1, V2> Tuple<V1, V2> tuple(V1 v1, V2 v2) {
-        return new Tuple<>(v1, v2);
-    }
-
-    private final V1 v1;
-    private final V2 v2;
-
-    public Tuple(V1 v1, V2 v2) {
-        this.v1 = v1;
-        this.v2 = v2;
-    }
-
-    public V1 v1() {
-        return v1;
-    }
-
-    public V2 v2() {
-        return v2;
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-
-        Tuple<?, ?> tuple = (Tuple<?, ?>) o;
-
-        if (v1 != null ? !v1.equals(tuple.v1) : tuple.v1 != null) return false;
-        if (v2 != null ? !v2.equals(tuple.v2) : tuple.v2 != null) return false;
-
-        return true;
-    }
-
-    @Override
-    public int hashCode() {
-        int result = v1 != null ? v1.hashCode() : 0;
-        result = 31 * result + (v2 != null ? v2.hashCode() : 0);
-        return result;
-    }
-
-    @Override
-    public String toString() {
-        return "Tuple [v1=" + v1 + ", v2=" + v2 + "]";
-    }
-}
diff --git a/server/src/main/java/org/opensearch/Assertions.java b/libs/core/src/main/java/org/opensearch/core/Assertions.java
similarity index 91%
rename from server/src/main/java/org/opensearch/Assertions.java
rename to libs/core/src/main/java/org/opensearch/core/Assertions.java
index 6873364f7987d..da93f2f435441 100644
--- a/server/src/main/java/org/opensearch/Assertions.java
+++ b/libs/core/src/main/java/org/opensearch/core/Assertions.java
@@ -30,12 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch;
+package org.opensearch.core;
 
 /**
  * Provides a static final field that can be used to check if assertions are enabled. Since this field might be used elsewhere to check if
  * assertions are enabled, if you are running with assertions enabled for specific packages or classes, you should enable assertions on this
- * class too (e.g., {@code -ea org.opensearch.Assertions -ea org.opensearch.cluster.service.MasterService}).
+ * class too (e.g., {@code -ea org.opensearch.core.Assertions -ea org.opensearch.cluster.service.ClusterManagerService}).
+ *
+ * @opensearch.internal
  */
 public final class Assertions {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/ParseField.java b/libs/core/src/main/java/org/opensearch/core/ParseField.java
similarity index 95%
rename from libs/x-content/src/main/java/org/opensearch/common/ParseField.java
rename to libs/core/src/main/java/org/opensearch/core/ParseField.java
index 8673e25bf567b..6c04ec0a96361 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/ParseField.java
+++ b/libs/core/src/main/java/org/opensearch/core/ParseField.java
@@ -29,10 +29,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common;
+package org.opensearch.core;
 
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.XContentLocation;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentLocation;
 
 import java.util.Collections;
 import java.util.HashSet;
@@ -43,7 +44,11 @@
 /**
  * Holds a field that can be found in a request while parsing and its different
  * variants, which may be deprecated.
+ *
+ * @opensearch.api
+ *
  */
+@PublicApi(since = "1.0.0")
 public class ParseField {
     private final String name;
     private final String[] deprecatedNames;
@@ -193,6 +198,11 @@ public String[] getDeprecatedNames() {
         return deprecatedNames;
     }
 
+    /**
+     * Common fields shared throughout the project
+     *
+     * @opensearch.internal
+     **/
     public static class CommonFields {
         public static final ParseField FIELD = new ParseField("field");
         public static final ParseField FIELDS = new ParseField("fields");
diff --git a/server/src/main/java/org/opensearch/action/ActionListener.java b/libs/core/src/main/java/org/opensearch/core/action/ActionListener.java
similarity index 98%
rename from server/src/main/java/org/opensearch/action/ActionListener.java
rename to libs/core/src/main/java/org/opensearch/core/action/ActionListener.java
index 13c6aa96ceee6..372f71957fcc5 100644
--- a/server/src/main/java/org/opensearch/action/ActionListener.java
+++ b/libs/core/src/main/java/org/opensearch/core/action/ActionListener.java
@@ -30,13 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.CheckedSupplier;
+import org.opensearch.common.annotation.PublicApi;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -45,7 +46,10 @@
 
 /**
  * A listener for action responses or failures.
+ *
+ * @opensearch.internal
  */
+@PublicApi(since = "1.0.0")
 public interface ActionListener<Response> {
     /**
      * Handle action response. This response may constitute a failure or a
diff --git a/server/src/main/java/org/opensearch/action/ActionResponse.java b/libs/core/src/main/java/org/opensearch/core/action/ActionResponse.java
similarity index 88%
rename from server/src/main/java/org/opensearch/action/ActionResponse.java
rename to libs/core/src/main/java/org/opensearch/core/action/ActionResponse.java
index 65008e7e0e279..3bb98c1d58e81 100644
--- a/server/src/main/java/org/opensearch/action/ActionResponse.java
+++ b/libs/core/src/main/java/org/opensearch/core/action/ActionResponse.java
@@ -30,15 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
 /**
  * Base class for responses to action requests.
+ *
+ * @opensearch.internal
  */
 public abstract class ActionResponse extends TransportResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/NotifyOnceListener.java b/libs/core/src/main/java/org/opensearch/core/action/NotifyOnceListener.java
similarity index 96%
rename from server/src/main/java/org/opensearch/action/NotifyOnceListener.java
rename to libs/core/src/main/java/org/opensearch/core/action/NotifyOnceListener.java
index 4935c34daa284..6af9ca005d171 100644
--- a/server/src/main/java/org/opensearch/action/NotifyOnceListener.java
+++ b/libs/core/src/main/java/org/opensearch/core/action/NotifyOnceListener.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -38,6 +38,8 @@
  * A listener that ensures that only one of onResponse or onFailure is called. And the method
  * the is called is only called once. Subclasses should implement notification logic with
  * innerOnResponse and innerOnFailure.
+ *
+ * @opensearch.internal
  */
 public abstract class NotifyOnceListener<Response> implements ActionListener<Response> {
 
diff --git a/server/src/main/java/org/opensearch/action/ShardOperationFailedException.java b/libs/core/src/main/java/org/opensearch/core/action/ShardOperationFailedException.java
similarity index 92%
rename from server/src/main/java/org/opensearch/action/ShardOperationFailedException.java
rename to libs/core/src/main/java/org/opensearch/core/action/ShardOperationFailedException.java
index f1f134c19115d..7456dcd335f72 100644
--- a/server/src/main/java/org/opensearch/action/ShardOperationFailedException.java
+++ b/libs/core/src/main/java/org/opensearch/core/action/ShardOperationFailedException.java
@@ -30,18 +30,19 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 import java.util.Objects;
 
 /**
  * An exception indicating that a failure occurred performing an operation on the shard.
  *
+ * @opensearch.internal
  */
 public abstract class ShardOperationFailedException implements Writeable, ToXContentObject {
 
diff --git a/libs/core/src/main/java/org/opensearch/core/action/package-info.java b/libs/core/src/main/java/org/opensearch/core/action/package-info.java
new file mode 100644
index 0000000000000..88cfb3326f8ed
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/action/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core action module */
+package org.opensearch.core.action;
diff --git a/server/src/main/java/org/opensearch/action/support/DefaultShardOperationFailedException.java b/libs/core/src/main/java/org/opensearch/core/action/support/DefaultShardOperationFailedException.java
similarity index 84%
rename from server/src/main/java/org/opensearch/action/support/DefaultShardOperationFailedException.java
rename to libs/core/src/main/java/org/opensearch/core/action/support/DefaultShardOperationFailedException.java
index 19f2c22d79496..777f8d04758d0 100644
--- a/server/src/main/java/org/opensearch/action/support/DefaultShardOperationFailedException.java
+++ b/libs/core/src/main/java/org/opensearch/core/action/support/DefaultShardOperationFailedException.java
@@ -30,25 +30,31 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action.support;
+package org.opensearch.core.action.support;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ShardOperationFailedException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 import static org.opensearch.ExceptionsHelper.detailedMessage;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.OpenSearchException.generateThrowableXContent;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Exception for a default shard operation
+ *
+ * @opensearch.internal
+ */
 public class DefaultShardOperationFailedException extends ShardOperationFailedException implements Writeable {
 
     private static final String INDEX = "index";
@@ -130,7 +136,7 @@ protected XContentBuilder innerToXContent(XContentBuilder builder, Params params
         builder.field("status", status.name());
         if (reason != null) {
             builder.startObject("reason");
-            OpenSearchException.generateThrowableXContent(builder, params, cause);
+            generateThrowableXContent(builder, params, cause);
             builder.endObject();
         }
         return builder;
diff --git a/libs/core/src/main/java/org/opensearch/core/action/support/package-info.java b/libs/core/src/main/java/org/opensearch/core/action/support/package-info.java
new file mode 100644
index 0000000000000..d0a1150d0750d
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/action/support/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Support classes for core action module */
+package org.opensearch.core.action.support;
diff --git a/server/src/main/java/org/opensearch/common/ParsingException.java b/libs/core/src/main/java/org/opensearch/core/common/ParsingException.java
similarity index 90%
rename from server/src/main/java/org/opensearch/common/ParsingException.java
rename to libs/core/src/main/java/org/opensearch/core/common/ParsingException.java
index 31129eaf1d882..b6dc7dc928b3e 100644
--- a/server/src/main/java/org/opensearch/common/ParsingException.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/ParsingException.java
@@ -30,15 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common;
+package org.opensearch.core.common;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
@@ -46,6 +46,8 @@
  * Exception that can be used when parsing queries with a given {@link
  * XContentParser}.
  * Can contain information about location of the error.
+ *
+ * @opensearch.internal
  */
 public class ParsingException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/common/Strings.java b/libs/core/src/main/java/org/opensearch/core/common/Strings.java
similarity index 83%
rename from server/src/main/java/org/opensearch/common/Strings.java
rename to libs/core/src/main/java/org/opensearch/core/common/Strings.java
index 139ace6c481c8..13468118abd38 100644
--- a/server/src/main/java/org/opensearch/common/Strings.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/Strings.java
@@ -6,40 +6,17 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common;
+package org.opensearch.core.common;
 
 import org.apache.lucene.util.BytesRefBuilder;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -59,9 +36,26 @@
 import static java.util.Collections.unmodifiableSet;
 import static org.opensearch.common.util.set.Sets.newHashSet;
 
+/**
+ * String utility class.
+ *
+ * TODO replace Strings in :server
+ *
+ * @opensearch.internal
+ */
 public class Strings {
-
+    public static final String UNKNOWN_UUID_VALUE = "_na_";
     public static final String[] EMPTY_ARRAY = new String[0];
+    public static final Set<Character> INVALID_FILENAME_CHARS = unmodifiableSet(
+        newHashSet('\\', '/', '*', '?', '"', '<', '>', '|', ' ', ',')
+    );
+
+    // no instance:
+    private Strings() {}
+
+    // ---------------------------------------------------------------------
+    // General convenience methods for working with Strings
+    // ---------------------------------------------------------------------
 
     public static void spaceify(int spaces, String from, StringBuilder to) throws Exception {
         try (BufferedReader reader = new BufferedReader(new StringReader(from))) {
@@ -75,71 +69,6 @@ public static void spaceify(int spaces, String from, StringBuilder to) throws Ex
         }
     }
 
-    /**
-     * Splits a backslash escaped string on the separator.
-     * <p>
-     * Current backslash escaping supported:
-     * <br> \n \t \r \b \f are escaped the same as a Java String
-     * <br> Other characters following a backslash are produced verbatim (\c =&gt; c)
-     *
-     * @param s         the string to split
-     * @param separator the separator to split on
-     * @param decode    decode backslash escaping
-     */
-    public static List<String> splitSmart(String s, String separator, boolean decode) {
-        ArrayList<String> lst = new ArrayList<>(2);
-        StringBuilder sb = new StringBuilder();
-        int pos = 0, end = s.length();
-        while (pos < end) {
-            if (s.startsWith(separator, pos)) {
-                if (sb.length() > 0) {
-                    lst.add(sb.toString());
-                    sb = new StringBuilder();
-                }
-                pos += separator.length();
-                continue;
-            }
-
-            char ch = s.charAt(pos++);
-            if (ch == '\\') {
-                if (!decode) sb.append(ch);
-                if (pos >= end) break;  // ERROR, or let it go?
-                ch = s.charAt(pos++);
-                if (decode) {
-                    switch (ch) {
-                        case 'n':
-                            ch = '\n';
-                            break;
-                        case 't':
-                            ch = '\t';
-                            break;
-                        case 'r':
-                            ch = '\r';
-                            break;
-                        case 'b':
-                            ch = '\b';
-                            break;
-                        case 'f':
-                            ch = '\f';
-                            break;
-                    }
-                }
-            }
-
-            sb.append(ch);
-        }
-
-        if (sb.length() > 0) {
-            lst.add(sb.toString());
-        }
-
-        return lst;
-    }
-
-    // ---------------------------------------------------------------------
-    // General convenience methods for working with Strings
-    // ---------------------------------------------------------------------
-
     /**
      * Check that the given CharSequence is neither <code>null</code> nor of length 0.
      * Note: Will return <code>true</code> for a CharSequence that purely consists of whitespace.
@@ -164,9 +93,9 @@ public static boolean hasLength(CharSequence str) {
      *
      * @param bytesReference the BytesReference to check (may be <code>null</code>)
      * @return <code>true</code> if the BytesReference is not null and has length
-     * @see #hasLength(CharSequence)
+     * @see Strings#hasLength(CharSequence)
      */
-    public static boolean hasLength(BytesReference bytesReference) {
+    public static boolean hasLength(final BytesReference bytesReference) {
         return (bytesReference != null && bytesReference.length() > 0);
     }
 
@@ -176,9 +105,9 @@ public static boolean hasLength(BytesReference bytesReference) {
      *
      * @param str the String to check (may be <code>null</code>)
      * @return <code>true</code> if the String is not null and has length
-     * @see #hasLength(CharSequence)
+     * @see Strings#hasLength(CharSequence)
      */
-    public static boolean hasLength(String str) {
+    public static boolean hasLength(final String str) {
         return hasLength((CharSequence) str);
     }
 
@@ -195,8 +124,8 @@ public static boolean hasLength(String str) {
      * @param str the CharSequence to check (may be <code>null</code>)
      * @return <code>true</code> if the CharSequence is either null or has a zero length
      */
-    public static boolean isEmpty(CharSequence str) {
-        return !hasLength(str);
+    public static boolean isEmpty(final CharSequence str) {
+        return hasLength(str) == false;
     }
 
     /**
@@ -214,7 +143,7 @@ public static boolean isEmpty(CharSequence str) {
      * @param str the CharSequence to check (may be <code>null</code>)
      * @return <code>true</code> if the CharSequence is not <code>null</code>,
      *         its length is greater than 0, and it does not contain whitespace only
-     * @see java.lang.Character#isWhitespace
+     * @see Character#isWhitespace
      */
     public static boolean hasText(CharSequence str) {
         if (!hasLength(str)) {
@@ -237,7 +166,7 @@ public static boolean hasText(CharSequence str) {
      * @param str the String to check (may be <code>null</code>)
      * @return <code>true</code> if the String is not <code>null</code>, its length is
      *         greater than 0, and it does not contain whitespace only
-     * @see #hasText(CharSequence)
+     * @see Strings#hasText(CharSequence)
      */
     public static boolean hasText(String str) {
         return hasText((CharSequence) str);
@@ -251,7 +180,7 @@ public static boolean hasText(String str) {
      * @return the trimmed String
      */
     public static String trimLeadingCharacter(String str, char leadingCharacter) {
-        if (!hasLength(str)) {
+        if (hasLength(str) == false) {
             return str;
         }
         StringBuilder sb = new StringBuilder(str);
@@ -328,7 +257,7 @@ public static String delete(String inString, String pattern) {
      * @return the resulting String
      */
     public static String deleteAny(String inString, String charsToDelete) {
-        if (!hasLength(inString) || !hasLength(charsToDelete)) {
+        if (hasLength(inString) == false || hasLength(charsToDelete) == false) {
             return inString;
         }
         StringBuilder sb = new StringBuilder();
@@ -382,10 +311,6 @@ private static String changeFirstCharacterCase(String str, boolean capitalize) {
         return sb.toString();
     }
 
-    public static final Set<Character> INVALID_FILENAME_CHARS = unmodifiableSet(
-        newHashSet('\\', '/', '*', '?', '"', '<', '>', '|', ' ', ',')
-    );
-
     public static boolean validFileName(String fileName) {
         for (int i = 0; i < fileName.length(); i++) {
             char c = fileName.charAt(i);
@@ -414,7 +339,7 @@ public static boolean validFileNameExcludingAstrix(String fileName) {
      * @return the String array (<code>null</code> if the passed-in
      *         Collection was <code>null</code>)
      */
-    public static String[] toStringArray(Collection<String> collection) {
+    public static String[] toStringArray(final Collection<String> collection) {
         if (collection == null) {
             return null;
         }
@@ -455,7 +380,7 @@ public static String[] splitStringByCommaToArray(final String s) {
      *         or <code>null</code> if the delimiter wasn't found in the given input String
      */
     public static String[] split(String toSplit, String delimiter) {
-        if (!hasLength(toSplit) || !hasLength(delimiter)) {
+        if (hasLength(toSplit) == false || hasLength(delimiter) == false) {
             return null;
         }
         int offset = toSplit.indexOf(delimiter);
@@ -479,13 +404,13 @@ public static String[] split(String toSplit, String delimiter) {
      * @param delimiters the delimiter characters, assembled as String
      *                   (each of those characters is individually considered as delimiter).
      * @return an array of the tokens
-     * @see java.util.StringTokenizer
-     * @see java.lang.String#trim()
-     * @see #delimitedListToStringArray
+     * @see StringTokenizer
+     * @see String#trim()
+     * @see Strings#delimitedListToStringArray
      */
     public static String[] tokenizeToStringArray(final String s, final String delimiters) {
         if (s == null) {
-            return EMPTY_ARRAY;
+            return Strings.EMPTY_ARRAY;
         }
         return toStringArray(tokenizeToCollection(s, delimiters, ArrayList::new));
     }
@@ -499,7 +424,7 @@ public static String[] tokenizeToStringArray(final String s, final String delimi
      * @param supplier   a collection supplier
      * @param <T>        the type of the collection
      * @return the tokens
-     * @see java.util.StringTokenizer
+     * @see StringTokenizer
      */
     private static <T extends Collection<String>> T tokenizeToCollection(
         final String s,
@@ -520,22 +445,6 @@ private static <T extends Collection<String>> T tokenizeToCollection(
         return tokens;
     }
 
-    /**
-     * Take a String which is a delimited list and convert it to a String array.
-     * <p>A single delimiter can consists of more than one character: It will still
-     * be considered as single delimiter string, rather than as bunch of potential
-     * delimiter characters - in contrast to <code>tokenizeToStringArray</code>.
-     *
-     * @param str       the input String
-     * @param delimiter the delimiter between elements (this is a single delimiter,
-     *                  rather than a bunch individual delimiter characters)
-     * @return an array of the tokens in the list
-     * @see #tokenizeToStringArray
-     */
-    public static String[] delimitedListToStringArray(String str, String delimiter) {
-        return delimitedListToStringArray(str, delimiter, null);
-    }
-
     /**
      * Take a String which is a delimited list and convert it to a String array.
      * <p>A single delimiter can consists of more than one character: It will still
@@ -552,7 +461,7 @@ public static String[] delimitedListToStringArray(String str, String delimiter)
      */
     public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete) {
         if (str == null) {
-            return EMPTY_ARRAY;
+            return Strings.EMPTY_ARRAY;
         }
         if (delimiter == null) {
             return new String[] { str };
@@ -577,6 +486,22 @@ public static String[] delimitedListToStringArray(String str, String delimiter,
         return toStringArray(result);
     }
 
+    /**
+     * Take a String which is a delimited list and convert it to a String array.
+     * <p>A single delimiter can consists of more than one character: It will still
+     * be considered as single delimiter string, rather than as bunch of potential
+     * delimiter characters - in contrast to <code>tokenizeToStringArray</code>.
+     *
+     * @param str       the input String
+     * @param delimiter the delimiter between elements (this is a single delimiter,
+     *                  rather than a bunch individual delimiter characters)
+     * @return an array of the tokens in the list
+     * @see Strings#tokenizeToStringArray
+     */
+    public static String[] delimitedListToStringArray(String str, String delimiter) {
+        return delimitedListToStringArray(str, delimiter, null);
+    }
+
     /**
      * Convert a CSV list into an array of Strings.
      *
@@ -716,12 +641,10 @@ public static String format1Decimals(double value, String suffix) {
      *
      * @param array the array to check
      */
-    private static boolean isEmpty(Object[] array) {
+    private static boolean isEmpty(final Object[] array) {
         return (array == null || array.length == 0);
     }
 
-    private Strings() {}
-
     public static byte[] toUTF8Bytes(CharSequence charSequence) {
         return toUTF8Bytes(charSequence, new BytesRefBuilder());
     }
@@ -768,8 +691,8 @@ public static boolean isAllOrWildcard(String data) {
      * Wraps the output into an anonymous object if needed. The content is not pretty-printed
      * nor human readable.
      */
-    public static String toString(ToXContent toXContent) {
-        return toString(toXContent, false, false);
+    public static String toString(MediaType mediaType, ToXContent toXContent) {
+        return toString(mediaType, toXContent, false, false);
     }
 
     /**
@@ -778,16 +701,8 @@ public static String toString(ToXContent toXContent) {
      * Allows to configure the params.
      * The content is not pretty-printed nor human readable.
      */
-    public static String toString(ToXContent toXContent, ToXContent.Params params) {
-        return toString(toXContent, params, false, false);
-    }
-
-    /**
-     * Returns a string representation of the builder (only applicable for text based xcontent).
-     * @param xContentBuilder builder containing an object to converted to a string
-     */
-    public static String toString(XContentBuilder xContentBuilder) {
-        return BytesReference.bytes(xContentBuilder).utf8ToString();
+    public static String toString(MediaType mediaType, ToXContent toXContent, ToXContent.Params params) {
+        return toString(mediaType, toXContent, params, false, false);
     }
 
     /**
@@ -796,8 +711,8 @@ public static String toString(XContentBuilder xContentBuilder) {
      * json needs to be pretty printed and human readable.
      *
      */
-    public static String toString(ToXContent toXContent, boolean pretty, boolean human) {
-        return toString(toXContent, ToXContent.EMPTY_PARAMS, pretty, human);
+    public static String toString(MediaType mediaType, ToXContent toXContent, boolean pretty, boolean human) {
+        return toString(mediaType, toXContent, ToXContent.EMPTY_PARAMS, pretty, human);
     }
 
     /**
@@ -806,9 +721,9 @@ public static String toString(ToXContent toXContent, boolean pretty, boolean hum
      * Allows to configure the params.
      * Allows to control whether the outputted json needs to be pretty printed and human readable.
      */
-    private static String toString(ToXContent toXContent, ToXContent.Params params, boolean pretty, boolean human) {
+    private static String toString(MediaType mediaType, ToXContent toXContent, ToXContent.Params params, boolean pretty, boolean human) {
         try {
-            XContentBuilder builder = createBuilder(pretty, human);
+            XContentBuilder builder = createBuilder(mediaType, pretty, human);
             if (toXContent.isFragment()) {
                 builder.startObject();
             }
@@ -816,23 +731,23 @@ private static String toString(ToXContent toXContent, ToXContent.Params params,
             if (toXContent.isFragment()) {
                 builder.endObject();
             }
-            return toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             try {
-                XContentBuilder builder = createBuilder(pretty, human);
+                XContentBuilder builder = createBuilder(mediaType, pretty, human);
                 builder.startObject();
                 builder.field("error", "error building toString out of XContent: " + e.getMessage());
                 builder.field("stack_trace", ExceptionsHelper.stackTrace(e));
                 builder.endObject();
-                return toString(builder);
+                return builder.toString();
             } catch (IOException e2) {
                 throw new OpenSearchException("cannot generate error message for deserialization", e);
             }
         }
     }
 
-    private static XContentBuilder createBuilder(boolean pretty, boolean human) throws IOException {
-        XContentBuilder builder = JsonXContent.contentBuilder();
+    private static XContentBuilder createBuilder(MediaType mediaType, boolean pretty, boolean human) throws IOException {
+        XContentBuilder builder = XContentBuilder.builder(mediaType.xContent());
         if (pretty) {
             builder.prettyPrint();
         }
@@ -870,10 +785,6 @@ public static boolean isNullOrEmpty(@Nullable String s) {
         return s == null || s.isEmpty();
     }
 
-    public static String coalesceToEmpty(@Nullable String s) {
-        return s == null ? "" : s;
-    }
-
     public static String padStart(String s, int minimumLength, char c) {
         if (s == null) {
             throw new NullPointerException("s");
diff --git a/server/src/main/java/org/opensearch/common/breaker/CircuitBreaker.java b/libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreaker.java
similarity index 76%
rename from server/src/main/java/org/opensearch/common/breaker/CircuitBreaker.java
rename to libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreaker.java
index ca6c5aa9698c3..846950ff17c63 100644
--- a/server/src/main/java/org/opensearch/common/breaker/CircuitBreaker.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreaker.java
@@ -30,13 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.breaker;
+package org.opensearch.core.common.breaker;
 
 import java.util.Locale;
 
 /**
  * Interface for an object that can be incremented, breaking after some
  * configured limit has been reached.
+ *
+ * @opensearch.internal
  */
 public interface CircuitBreaker {
 
@@ -67,14 +69,25 @@ public interface CircuitBreaker {
      */
     String IN_FLIGHT_REQUESTS = "in_flight_requests";
 
+    /**
+     * The type of breaker
+     * can be {@link #MEMORY}, {@link #PARENT}, or {@link #NOOP}
+     * @opensearch.internal
+     */
     enum Type {
-        // A regular or ChildMemoryCircuitBreaker
+        /** A regular or ChildMemoryCircuitBreaker */
         MEMORY,
-        // A special parent-type for the hierarchy breaker service
+        /** A special parent-type for the hierarchy breaker service */
         PARENT,
-        // A breaker where every action is a noop, it never breaks
+        /** A breaker where every action is a noop, it never breaks */
         NOOP;
 
+        /**
+         * Converts string (case-insensitive) to breaker {@link Type}
+         * @param value "noop", "parent", or "memory" (case-insensitive)
+         * @return the breaker {@link Type}
+         * @throws IllegalArgumentException if value is not "noop", "parent", or "memory"
+         */
         public static Type parseValue(String value) {
             switch (value.toLowerCase(Locale.ROOT)) {
                 case "noop":
@@ -89,10 +102,15 @@ public static Type parseValue(String value) {
         }
     }
 
+    /**
+     * The breaker durability
+     * can be {@link #TRANSIENT} or {@link #PERMANENT}
+     * @opensearch.internal
+     */
     enum Durability {
-        // The condition that tripped the circuit breaker fixes itself eventually.
+        /** The condition that tripped the circuit breaker fixes itself eventually. */
         TRANSIENT,
-        // The condition that tripped the circuit breaker requires manual intervention.
+        /** The condition that tripped the circuit breaker requires manual intervention. */
         PERMANENT
     }
 
@@ -108,11 +126,14 @@ enum Durability {
      * @param bytes number of bytes to add
      * @param label string label describing the bytes being added
      * @return the number of "used" bytes for the circuit breaker
+     * @throws CircuitBreakingException if the breaker tripped
      */
     double addEstimateBytesAndMaybeBreak(long bytes, String label) throws CircuitBreakingException;
 
     /**
      * Adjust the circuit breaker without tripping
+     * @param bytes number of bytes to add
+     * @return the number of "used" bytes for the circuit breaker
      */
     long addWithoutBreaking(long bytes);
 
@@ -142,7 +163,10 @@ enum Durability {
     String getName();
 
     /**
-     * @return whether a tripped circuit breaker will reset itself (transient) or requires manual intervention (permanent).
+     * Returns the {@link Durability} of this breaker
+     * @return whether a tripped circuit breaker will
+     * reset itself ({@link Durability#TRANSIENT})
+     * or requires manual intervention ({@link Durability#PERMANENT}).
      */
     Durability getDurability();
 
diff --git a/server/src/main/java/org/opensearch/common/breaker/CircuitBreakingException.java b/libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreakingException.java
similarity index 86%
rename from server/src/main/java/org/opensearch/common/breaker/CircuitBreakingException.java
rename to libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreakingException.java
index 8983ad3b46e60..52a34a103e775 100644
--- a/server/src/main/java/org/opensearch/common/breaker/CircuitBreakingException.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/breaker/CircuitBreakingException.java
@@ -29,24 +29,29 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.breaker;
+package org.opensearch.core.common.breaker;
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Exception thrown when the circuit breaker trips
+ *
+ * @opensearch.internal
  */
 public class CircuitBreakingException extends OpenSearchException {
 
+    /** The number of bytes wanted */
     private final long bytesWanted;
+    /** The circuit breaker limit */
     private final long byteLimit;
+    /** The {@link CircuitBreaker.Durability} of the circuit breaker */
     private final CircuitBreaker.Durability durability;
 
     public CircuitBreakingException(StreamInput in) throws IOException {
@@ -93,6 +98,7 @@ public CircuitBreaker.Durability getDurability() {
         return durability;
     }
 
+    /** Always returns {@link RestStatus#TOO_MANY_REQUESTS} */
     @Override
     public RestStatus status() {
         return RestStatus.TOO_MANY_REQUESTS;
diff --git a/libs/core/src/main/java/org/opensearch/core/common/breaker/NoopCircuitBreaker.java b/libs/core/src/main/java/org/opensearch/core/common/breaker/NoopCircuitBreaker.java
new file mode 100644
index 0000000000000..17b9fefd27c99
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/breaker/NoopCircuitBreaker.java
@@ -0,0 +1,152 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.common.breaker;
+
+/**
+ * A {@link CircuitBreaker} that doesn't increment or adjust, and all operations are
+ * basically noops.
+ * It never trips, limit is always -1, always returns 0 for all metrics.
+ * @opensearch.internal
+ */
+public class NoopCircuitBreaker implements CircuitBreaker {
+
+    /** The limit of this breaker is always -1 */
+    public static final int LIMIT = -1;
+    /** Name of this breaker */
+    private final String name;
+
+    /**
+     * Creates a new NoopCircuitBreaker (that never trip) with the given name
+     * @param name the name of this breaker
+     */
+    public NoopCircuitBreaker(String name) {
+        this.name = name;
+    }
+
+    /**
+     * This is a noop, a noop breaker never trip
+     * @param fieldName name of this noop breaker
+     * @param bytesNeeded bytes needed
+     */
+    @Override
+    public void circuitBreak(String fieldName, long bytesNeeded) {
+        // noop
+    }
+
+    /**
+     * This is a noop, always return 0 and never throw/trip
+     * @param bytes number of bytes to add
+     * @param label string label describing the bytes being added
+     * @return always return 0
+     * @throws CircuitBreakingException never thrown
+     */
+    @Override
+    public double addEstimateBytesAndMaybeBreak(long bytes, String label) throws CircuitBreakingException {
+        return 0;
+    }
+
+    /**
+     * This is a noop, nothing is added, always return 0
+     * @param bytes number of bytes to add (ignored)
+     * @return always return 0
+     */
+    @Override
+    public long addWithoutBreaking(long bytes) {
+        return 0;
+    }
+
+    /**
+     * This is a noop, always return 0
+     * @return always return 0
+     */
+    @Override
+    public long getUsed() {
+        return 0;
+    }
+
+    /**
+     * A noop breaker have a constant limit of -1
+     * @return always return -1
+     */
+    @Override
+    public long getLimit() {
+        return LIMIT;
+    }
+
+    /**
+     * A noop breaker have no overhead, always return 0
+     * @return always return 0
+     */
+    @Override
+    public double getOverhead() {
+        return 0;
+    }
+
+    /**
+     * A noop breaker never trip, always return 0
+     * @return always return 0
+     */
+    @Override
+    public long getTrippedCount() {
+        return 0;
+    }
+
+    /**
+     * return the name of this breaker
+     * @return the name of this breaker
+     */
+    @Override
+    public String getName() {
+        return this.name;
+    }
+
+    /**
+     * A noop breaker {@link Durability} is always {@link Durability#PERMANENT}
+     * @return always return {@link Durability#PERMANENT }
+     */
+    @Override
+    public Durability getDurability() {
+        return Durability.PERMANENT;
+    }
+
+    /**
+     * Limit and overhead are constant for a noop breaker.
+     * this is a noop.
+     * @param limit the desired limit (ignored)
+     * @param overhead the desired overhead (ignored)
+     */
+    @Override
+    public void setLimitAndOverhead(long limit, double overhead) {
+        // noop
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/common/breaker/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/breaker/package-info.java
new file mode 100644
index 0000000000000..f9fb83d2207e1
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/breaker/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Foundation classes for the Circuit Breaker
+ */
+package org.opensearch.core.common.breaker;
diff --git a/server/src/main/java/org/opensearch/common/bytes/AbstractBytesReference.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/AbstractBytesReference.java
similarity index 93%
rename from server/src/main/java/org/opensearch/common/bytes/AbstractBytesReference.java
rename to libs/core/src/main/java/org/opensearch/core/common/bytes/AbstractBytesReference.java
index 77ee4df7da2cb..8c1efcd00c24e 100644
--- a/server/src/main/java/org/opensearch/common/bytes/AbstractBytesReference.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/AbstractBytesReference.java
@@ -29,21 +29,29 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.bytes;
+package org.opensearch.core.common.bytes;
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.apache.lucene.util.UnicodeUtil;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.function.ToIntBiFunction;
 
+/**
+ * Base bytesref class
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractBytesReference implements BytesReference {
 
-    private Integer hash = null; // we cache the hash of this reference since it can be quite costly to re-calculated it
+    /** we cache the hash of this reference since it can be quite costly to re-calculated it */
+    private Integer hash = null;
+    private static final int MAX_UTF16_LENGTH = Integer.MAX_VALUE >> 1;
 
     @Override
     public int getInt(int index) {
@@ -75,9 +83,19 @@ public void writeTo(OutputStream os) throws IOException {
         }
     }
 
+    protected int getMaxUTF16Length() {
+        return MAX_UTF16_LENGTH;
+    }
+
     @Override
     public String utf8ToString() {
-        return toBytesRef().utf8ToString();
+        BytesRef bytesRef = toBytesRef();
+        final char[] ref = new char[bytesRef.length];
+        final int len = UnicodeUtil.UTF8toUTF16(bytesRef, ref);
+        if (len > getMaxUTF16Length()) {
+            throw new IllegalArgumentException("UTF16 String size is " + len + ", should be less than " + getMaxUTF16Length());
+        }
+        return new String(ref, 0, len);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/common/bytes/BytesArray.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/BytesArray.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/bytes/BytesArray.java
rename to libs/core/src/main/java/org/opensearch/core/common/bytes/BytesArray.java
index 69f715856c696..ae04ddcc19eee 100644
--- a/server/src/main/java/org/opensearch/common/bytes/BytesArray.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/BytesArray.java
@@ -30,15 +30,20 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.bytes;
+package org.opensearch.core.common.bytes;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
 
+/**
+ * A bytes array.
+ *
+ * @opensearch.internal
+ */
 public final class BytesArray extends AbstractBytesReference {
 
     public static final BytesArray EMPTY = new BytesArray(BytesRef.EMPTY_BYTES, 0, 0);
diff --git a/server/src/main/java/org/opensearch/common/bytes/BytesReference.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/BytesReference.java
similarity index 89%
rename from server/src/main/java/org/opensearch/common/bytes/BytesReference.java
rename to libs/core/src/main/java/org/opensearch/core/common/bytes/BytesReference.java
index 1107eda4b5a81..bb26e4e8a8675 100644
--- a/server/src/main/java/org/opensearch/common/bytes/BytesReference.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/BytesReference.java
@@ -30,16 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.bytes;
+package org.opensearch.core.common.bytes;
 
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.io.stream.BytesStream;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.util.ByteArray;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -49,7 +50,10 @@
 
 /**
  * A reference to bytes.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface BytesReference extends Comparable<BytesReference>, ToXContentFragment {
 
     /**
@@ -120,8 +124,13 @@ static BytesReference fromByteBuffers(ByteBuffer[] buffers) {
      * Returns BytesReference composed of the provided ByteBuffer.
      */
     static BytesReference fromByteBuffer(ByteBuffer buffer) {
-        assert buffer.hasArray();
-        return new BytesArray(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining());
+        if (buffer.hasArray()) {
+            return new BytesArray(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining());
+        } else {
+            final byte[] array = new byte[buffer.remaining()];
+            buffer.asReadOnlyBuffer().get(array, 0, buffer.remaining());
+            return new BytesArray(array);
+        }
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/bytes/CompositeBytesReference.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/CompositeBytesReference.java
similarity index 99%
rename from server/src/main/java/org/opensearch/common/bytes/CompositeBytesReference.java
rename to libs/core/src/main/java/org/opensearch/core/common/bytes/CompositeBytesReference.java
index 2a989e33e918f..53915a3da824c 100644
--- a/server/src/main/java/org/opensearch/common/bytes/CompositeBytesReference.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/CompositeBytesReference.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.bytes;
+package org.opensearch.core.common.bytes;
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
@@ -47,6 +47,8 @@
  * into one without copying.
  *
  * Note, {@link #toBytesRef()} will materialize all pages in this BytesReference.
+ *
+ * @opensearch.internal
  */
 public final class CompositeBytesReference extends AbstractBytesReference {
 
diff --git a/server/src/main/java/org/opensearch/common/bytes/PagedBytesReference.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/PagedBytesReference.java
similarity index 93%
rename from server/src/main/java/org/opensearch/common/bytes/PagedBytesReference.java
rename to libs/core/src/main/java/org/opensearch/core/common/bytes/PagedBytesReference.java
index f9a2c6b95c03b..6b2ae821d2841 100644
--- a/server/src/main/java/org/opensearch/common/bytes/PagedBytesReference.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/PagedBytesReference.java
@@ -30,22 +30,23 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.bytes;
+package org.opensearch.core.common.bytes;
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.util.ByteArray;
-import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.util.ByteArray;
 
 import java.io.IOException;
 
 /**
  * A page based bytes reference, internally holding the bytes in a paged
  * data structure.
+ *
+ * @opensearch.internal
  */
 public class PagedBytesReference extends AbstractBytesReference {
 
-    private static final int PAGE_SIZE = PageCacheRecycler.BYTE_PAGE_SIZE;
+    public static final int PAGE_SIZE_IN_BYTES = 1 << 14;
 
     private final ByteArray byteArray;
     private final int offset;
@@ -93,7 +94,7 @@ public final BytesRefIterator iterator() {
         // we calculate the initial fragment size here to ensure that if this reference is a slice we are still page aligned
         // across the entire iteration. The first page is smaller if our offset != 0 then we start in the middle of the page
         // otherwise we iterate full pages until we reach the last chunk which also might end within a page.
-        final int initialFragmentSize = offset != 0 ? PAGE_SIZE - (offset % PAGE_SIZE) : PAGE_SIZE;
+        final int initialFragmentSize = offset != 0 ? PAGE_SIZE_IN_BYTES - (offset % PAGE_SIZE_IN_BYTES) : PAGE_SIZE_IN_BYTES;
         return new BytesRefIterator() {
             int position = 0;
             int nextFragmentSize = Math.min(length, initialFragmentSize);
@@ -107,7 +108,7 @@ public BytesRef next() throws IOException {
                     assert materialized == false : "iteration should be page aligned but array got materialized";
                     position += nextFragmentSize;
                     final int remaining = length - position;
-                    nextFragmentSize = Math.min(remaining, PAGE_SIZE);
+                    nextFragmentSize = Math.min(remaining, PAGE_SIZE_IN_BYTES);
                     return slice;
                 } else {
                     assert nextFragmentSize == 0 : "fragmentSize expected [0] but was: [" + nextFragmentSize + "]";
diff --git a/libs/core/src/main/java/org/opensearch/core/common/bytes/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/bytes/package-info.java
new file mode 100644
index 0000000000000..d197e07f3e5fe
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/bytes/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core Bytes module */
+package org.opensearch.core.common.bytes;
diff --git a/libs/core/src/main/java/org/opensearch/core/common/io/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/io/package-info.java
new file mode 100644
index 0000000000000..7f5318f53dd35
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core io module */
+package org.opensearch.core.common.io;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/ByteBufferStreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/ByteBufferStreamInput.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/io/stream/ByteBufferStreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/ByteBufferStreamInput.java
index 92b38e67f02c8..fcbab461b14c3 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/ByteBufferStreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/ByteBufferStreamInput.java
@@ -29,13 +29,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import java.io.EOFException;
 import java.io.IOException;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 
+/**
+ * Byte Buffer Stream Input
+ *
+ * @opensearch.internal
+ */
 public class ByteBufferStreamInput extends StreamInput {
 
     private final ByteBuffer buffer;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/BytesStream.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStream.java
similarity index 88%
rename from server/src/main/java/org/opensearch/common/io/stream/BytesStream.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStream.java
index 1a4e34d9e7e0e..70bf9c7710e2a 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/BytesStream.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStream.java
@@ -30,10 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
+/**
+ * Base Bytes Stream.
+ *
+ * @opensearch.internal
+ */
 public abstract class BytesStream extends StreamOutput {
 
     public abstract BytesReference bytes();
diff --git a/server/src/main/java/org/opensearch/common/io/stream/BytesStreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStreamInput.java
similarity index 87%
rename from server/src/main/java/org/opensearch/common/io/stream/BytesStreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStreamInput.java
index e593f3c89b008..a50d1c165ed72 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/BytesStreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/BytesStreamInput.java
@@ -6,7 +6,7 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
 
@@ -34,6 +34,8 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
+ *
+ * @opensearch.internal
  */
 public class BytesStreamInput extends StreamInput {
     private byte[] bytes;
@@ -78,15 +80,19 @@ public void skipBytes(long count) {
         pos += count;
     }
 
-    // NOTE: AIOOBE not EOF if you read too much
     @Override
-    public byte readByte() {
+    public byte readByte() throws EOFException {
+        if (eof()) {
+            throw new EOFException();
+        }
         return bytes[pos++];
     }
 
-    // NOTE: AIOOBE not EOF if you read too much
     @Override
-    public void readBytes(byte[] b, int offset, int len) {
+    public void readBytes(byte[] b, int offset, int len) throws EOFException {
+        if (available() < len) {
+            throw new EOFException();
+        }
         System.arraycopy(bytes, pos, b, offset, len);
         pos += len;
     }
@@ -109,6 +115,9 @@ protected void ensureCanReadBytes(int length) throws EOFException {
 
     @Override
     public int read() throws IOException {
+        if (eof()) {
+            throw new EOFException();
+        }
         return bytes[pos++] & 0xFF;
     }
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/DataOutputStreamOutput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/DataOutputStreamOutput.java
similarity index 94%
rename from server/src/main/java/org/opensearch/common/io/stream/DataOutputStreamOutput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/DataOutputStreamOutput.java
index 9fcbc39417257..b0bd6b101dc70 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/DataOutputStreamOutput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/DataOutputStreamOutput.java
@@ -30,12 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import java.io.Closeable;
 import java.io.DataOutput;
 import java.io.IOException;
 
+/**
+ * Main stream output for data output
+ *
+ * @opensearch.internal
+ */
 public class DataOutputStreamOutput extends StreamOutput {
 
     private final DataOutput out;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/FilterStreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/FilterStreamInput.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/io/stream/FilterStreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/FilterStreamInput.java
index 7c5ebde4b5eae..a6e49567ac7d5 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/FilterStreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/FilterStreamInput.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.opensearch.Version;
 
@@ -39,6 +39,8 @@
 
 /**
  * Wraps a {@link StreamInput} and delegates to it. To be used to add functionality to an existing stream by subclassing.
+ *
+ * @opensearch.internal
  */
 public abstract class FilterStreamInput extends StreamInput {
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/InputStreamStreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/InputStreamStreamInput.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/io/stream/InputStreamStreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/InputStreamStreamInput.java
index f46ecc09f6416..e86ad44fb1dc4 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/InputStreamStreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/InputStreamStreamInput.java
@@ -30,14 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
-
-import org.opensearch.common.io.Streams;
+package org.opensearch.core.common.io.stream;
 
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
 
+/**
+ * Main input stream for input data
+ *
+ * @opensearch.internal
+ */
 public class InputStreamStreamInput extends StreamInput {
 
     private final InputStream is;
@@ -75,7 +78,7 @@ public byte readByte() throws IOException {
     @Override
     public void readBytes(byte[] b, int offset, int len) throws IOException {
         if (len < 0) throw new IndexOutOfBoundsException();
-        final int read = Streams.readFully(is, b, offset, len);
+        final int read = is.readNBytes(b, offset, len);
         if (read != len) {
             throw new EOFException();
         }
diff --git a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteable.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteable.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/io/stream/NamedWriteable.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteable.java
index e61cb729d8463..ae6aa5a9e9a17 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteable.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteable.java
@@ -30,12 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 /**
  * A {@link Writeable} object identified by its name.
  * To be used for arbitrary serializable objects (e.g. queries); when reading them, their name tells
  * which specific object needs to be created.
+ *
+ * @opensearch.internal
  */
 public interface NamedWriteable extends Writeable {
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteableAwareStreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableAwareStreamInput.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/io/stream/NamedWriteableAwareStreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableAwareStreamInput.java
index e695cbec979e5..298090a18dec6 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteableAwareStreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableAwareStreamInput.java
@@ -30,12 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import java.io.IOException;
 
 /**
  * Wraps a {@link StreamInput} and associates it with a {@link NamedWriteableRegistry}
+ *
+ * @opensearch.internal
  */
 public class NamedWriteableAwareStreamInput extends FilterStreamInput {
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteableRegistry.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableRegistry.java
similarity index 91%
rename from server/src/main/java/org/opensearch/common/io/stream/NamedWriteableRegistry.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableRegistry.java
index 15de91e551a15..abac76c8b6c27 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/NamedWriteableRegistry.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NamedWriteableRegistry.java
@@ -30,7 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
+
+import org.opensearch.common.annotation.PublicApi;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -40,14 +42,22 @@
 import java.util.Objects;
 
 /**
- * A registry for {@link org.opensearch.common.io.stream.Writeable.Reader} readers of {@link NamedWriteable}.
+ * A registry for {@link Writeable.Reader} readers of {@link NamedWriteable}.
  *
  * The registration is keyed by the combination of the category class of {@link NamedWriteable}, and a name unique
  * to that category.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class NamedWriteableRegistry {
 
-    /** An entry in the registry, made up of a category class and name, and a reader for that category class. */
+    /**
+     * An entry in the registry, made up of a category class and name, and a reader for that category class.
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public static class Entry {
 
         /** The superclass of a {@link NamedWriteable} which will be read by {@link #reader}. */
@@ -86,6 +96,7 @@ public NamedWriteableRegistry(List<Entry> entries) {
 
         Map<Class<?>, Map<String, Writeable.Reader<?>>> registry = new HashMap<>();
         Map<String, Writeable.Reader<?>> readers = null;
+        @SuppressWarnings("rawtypes")
         Class currentCategory = null;
         for (Entry entry : entries) {
             if (currentCategory != entry.categoryClass) {
diff --git a/server/src/main/java/org/opensearch/common/io/stream/NotSerializableExceptionWrapper.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NotSerializableExceptionWrapper.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/io/stream/NotSerializableExceptionWrapper.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/NotSerializableExceptionWrapper.java
index e1e0f69aadb09..91d552be0950c 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/NotSerializableExceptionWrapper.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/NotSerializableExceptionWrapper.java
@@ -30,11 +30,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
@@ -44,6 +44,8 @@
  * This class will preserve the stacktrace as well as the suppressed exceptions of
  * the throwable it was created with instead of it's own. The stacktrace has no indication
  * of where this exception was created.
+ *
+ * @opensearch.internal
  */
 public final class NotSerializableExceptionWrapper extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/OutputStreamStreamOutput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/OutputStreamStreamOutput.java
similarity index 94%
rename from server/src/main/java/org/opensearch/common/io/stream/OutputStreamStreamOutput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/OutputStreamStreamOutput.java
index c849ed9e523f9..cf45e0e0b9088 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/OutputStreamStreamOutput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/OutputStreamStreamOutput.java
@@ -30,11 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import java.io.IOException;
 import java.io.OutputStream;
 
+/**
+ * Streaming output data
+ *
+ * @opensearch.internal
+ */
 public class OutputStreamStreamOutput extends StreamOutput {
 
     private final OutputStream out;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/StreamInput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamInput.java
similarity index 94%
rename from server/src/main/java/org/opensearch/common/io/stream/StreamInput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamInput.java
index fc50a4f8b08fe..1499767c5e1a0 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/StreamInput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamInput.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
@@ -41,22 +41,21 @@
 import org.apache.lucene.util.BitUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.CharsRef;
-import org.joda.time.DateTimeZone;
+import org.opensearch.Build;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.common.CharArrays;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.settings.SecureString;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.time.DateUtils;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.script.JodaCompatibleZonedDateTime;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 
 import java.io.ByteArrayInputStream;
 import java.io.EOFException;
@@ -105,7 +104,10 @@
  * everywhere. That being said, this class deals primarily with {@code List}s rather than Arrays. For the most part calls should adapt to
  * lists, either by storing {@code List}s internally or just converting to and from a {@code List} when calling. This comment is repeated
  * on {@link StreamInput}.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public abstract class StreamInput extends InputStream {
 
     private Version version = Version.CURRENT;
@@ -179,6 +181,10 @@ public BytesRef readBytesRef() throws IOException {
         return readBytesRef(length);
     }
 
+    public void readFully(byte[] b) throws IOException {
+        readBytes(b, 0, b.length);
+    }
+
     public BytesRef readBytesRef(int length) throws IOException {
         if (length == 0) {
             return new BytesRef();
@@ -188,10 +194,6 @@ public BytesRef readBytesRef(int length) throws IOException {
         return new BytesRef(bytes, 0, length);
     }
 
-    public void readFully(byte[] b) throws IOException {
-        readBytes(b, 0, b.length);
-    }
-
     public short readShort() throws IOException {
         return (short) (((readByte() & 0xFF) << 8) | (readByte() & 0xFF));
     }
@@ -203,16 +205,6 @@ public int readInt() throws IOException {
         return ((readByte() & 0xFF) << 24) | ((readByte() & 0xFF) << 16) | ((readByte() & 0xFF) << 8) | (readByte() & 0xFF);
     }
 
-    /**
-     * Reads an optional {@link Integer}.
-     */
-    public Integer readOptionalInt() throws IOException {
-        if (readBoolean()) {
-            return readInt();
-        }
-        return null;
-    }
-
     /**
      * Reads an int stored in variable-length format.  Reads between one and
      * five bytes.  Smaller values take fewer bytes.  Negative numbers
@@ -247,6 +239,16 @@ public int readVInt() throws IOException {
         return i | ((b & 0x7F) << 28);
     }
 
+    /**
+     * Reads an optional {@link Integer}.
+     */
+    public Integer readOptionalInt() throws IOException {
+        if (readBoolean()) {
+            return readInt();
+        }
+        return null;
+    }
+
     /**
      * Reads eight bytes and returns a long.
      */
@@ -346,6 +348,10 @@ public BigInteger readBigInteger() throws IOException {
         return new BigInteger(readString());
     }
 
+    public MediaType readMediaType() throws IOException {
+        return MediaTypeRegistry.fromMediaType(readString());
+    }
+
     @Nullable
     public Text readOptionalText() throws IOException {
         int length = readInt();
@@ -677,25 +683,6 @@ public Map<String, Object> readMap() throws IOException {
         return (Map<String, Object>) readGenericValue();
     }
 
-    /**
-     * Read {@link ImmutableOpenMap} using given key and value readers.
-     *
-     * @param keyReader   key reader
-     * @param valueReader value reader
-     */
-    public <K, V> ImmutableOpenMap<K, V> readImmutableMap(Writeable.Reader<K> keyReader, Writeable.Reader<V> valueReader)
-        throws IOException {
-        final int size = readVInt();
-        if (size == 0) {
-            return ImmutableOpenMap.of();
-        }
-        final ImmutableOpenMap.Builder<K, V> builder = ImmutableOpenMap.builder(size);
-        for (int i = 0; i < size; i++) {
-            builder.put(keyReader.read(this), valueReader.read(this));
-        }
-        return builder.build();
-    }
-
     /**
      * Reads a value of unspecified type. If a collection is read then the collection will be mutable if it contains any entry but might
      * be immutable if it is empty.
@@ -703,6 +690,11 @@ public <K, V> ImmutableOpenMap<K, V> readImmutableMap(Writeable.Reader<K> keyRea
     @Nullable
     public Object readGenericValue() throws IOException {
         byte type = readByte();
+        Writeable.Reader<?> r = Writeable.WriteableRegistry.getReader(type);
+        if (r != null) {
+            return r.read(this);
+        }
+
         switch (type) {
             case -1:
                 return null;
@@ -732,8 +724,6 @@ public Object readGenericValue() throws IOException {
                 return readByte();
             case 12:
                 return readDate();
-            case 13:
-                return readDateTime();
             case 14:
                 return readBytesReference();
             case 15:
@@ -750,8 +740,6 @@ public Object readGenericValue() throws IOException {
                 return readDoubleArray();
             case 21:
                 return readBytesRef();
-            case 22:
-                return readGeoPoint();
             case 23:
                 return readZonedDateTime();
             case 24:
@@ -782,7 +770,7 @@ public final Instant readOptionalInstant() throws IOException {
         return present ? readInstant() : null;
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({ "rawtypes", "unchecked" })
     private List readArrayList() throws IOException {
         int size = readArraySize();
         if (size == 0) {
@@ -795,14 +783,6 @@ private List readArrayList() throws IOException {
         return list;
     }
 
-    private JodaCompatibleZonedDateTime readDateTime() throws IOException {
-        // we reuse DateTime to communicate with older nodes that don't know about the joda compat layer, but
-        // here we are on a new node so we always want a compat datetime
-        final ZoneId zoneId = DateUtils.dateTimeZoneToZoneId(DateTimeZone.forID(readString()));
-        long millis = readLong();
-        return new JodaCompatibleZonedDateTime(Instant.ofEpochMilli(millis), zoneId);
-    }
-
     private ZonedDateTime readZonedDateTime() throws IOException {
         final String timeZoneId = readString();
         return ZonedDateTime.ofInstant(Instant.ofEpochMilli(readLong()), ZoneId.of(timeZoneId));
@@ -822,6 +802,7 @@ private Object[] readArray() throws IOException {
         return list8;
     }
 
+    @SuppressWarnings({ "rawtypes", "unchecked" })
     private Map readLinkedHashMap() throws IOException {
         int size9 = readArraySize();
         if (size9 == 0) {
@@ -834,6 +815,7 @@ private Map readLinkedHashMap() throws IOException {
         return map9;
     }
 
+    @SuppressWarnings({ "rawtypes", "unchecked" })
     private Map readHashMap() throws IOException {
         int size10 = readArraySize();
         if (size10 == 0) {
@@ -851,31 +833,7 @@ private Date readDate() throws IOException {
     }
 
     /**
-     * Reads a {@link GeoPoint} from this stream input
-     */
-    public GeoPoint readGeoPoint() throws IOException {
-        return new GeoPoint(readDouble(), readDouble());
-    }
-
-    /**
-     * Read a {@linkplain DateTimeZone}.
-     */
-    public DateTimeZone readTimeZone() throws IOException {
-        return DateTimeZone.forID(readString());
-    }
-
-    /**
-     * Read an optional {@linkplain DateTimeZone}.
-     */
-    public DateTimeZone readOptionalTimeZone() throws IOException {
-        if (readBoolean()) {
-            return DateTimeZone.forID(readString());
-        }
-        return null;
-    }
-
-    /**
-     * Read a {@linkplain DateTimeZone}.
+     * Read a {@linkplain ZoneId}.
      */
     public ZoneId readZoneId() throws IOException {
         return ZoneId.of(readString());
@@ -984,7 +942,7 @@ public byte[] readByteArray() throws IOException {
     }
 
     /**
-     * Reads an array from the stream using the specified {@link org.opensearch.common.io.stream.Writeable.Reader} to read array elements
+     * Reads an array from the stream using the specified {@link Writeable.Reader} to read array elements
      * from the stream. This method can be seen as the reader version of {@link StreamOutput#writeArray(Writeable.Writer, Object[])}. It is
      * assumed that the stream first contains a variable-length integer representing the size of the array, and then contains that many
      * elements that can be read from the stream.
@@ -1125,6 +1083,24 @@ public <T extends Exception> T readException() throws IOException {
         return null;
     }
 
+    /** Reads the OpenSearch Version from the input stream */
+    public Version readVersion() throws IOException {
+        return Version.fromId(readVInt());
+    }
+
+    /** Reads the {@link Version} from the input stream */
+    public Build readBuild() throws IOException {
+        // the following is new for opensearch: we write the distribution to support any "forks"
+        final String distribution = readString();
+        // be lenient when reading on the wire, the enumeration values from other versions might be different than what we know
+        final Build.Type type = Build.Type.fromDisplayName(readString(), false);
+        String hash = readString();
+        String date = readString();
+        boolean snapshot = readBoolean();
+        final String version = readString();
+        return new Build(type, hash, date, snapshot, version, distribution);
+    }
+
     /**
      * Get the registry of named writeables if this stream has one,
      * {@code null} otherwise.
diff --git a/server/src/main/java/org/opensearch/common/io/stream/StreamOutput.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamOutput.java
similarity index 91%
rename from server/src/main/java/org/opensearch/common/io/stream/StreamOutput.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamOutput.java
index e53e24171d8b6..94b813246bc7e 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/StreamOutput.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/StreamOutput.java
@@ -30,9 +30,8 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
 import org.apache.lucene.index.IndexFormatTooOldException;
@@ -41,24 +40,20 @@
 import org.apache.lucene.util.BitUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.joda.time.DateTimeZone;
-import org.joda.time.ReadableInstant;
+import org.opensearch.Build;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.CharArrays;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.Writeable.Writer;
-import org.opensearch.common.settings.SecureString;
-import org.opensearch.common.text.Text;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.script.JodaCompatibleZonedDateTime;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable.WriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable.Writer;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 
 import java.io.EOFException;
 import java.io.FileNotFoundException;
@@ -101,7 +96,10 @@
  * everywhere. That being said, this class deals primarily with {@code List}s rather than Arrays. For the most part calls should adapt to
  * lists, either by storing {@code List}s internally or just converting to and from a {@code List} when calling. This comment is repeated
  * on {@link StreamInput}.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public abstract class StreamOutput extends OutputStream {
 
     private static final int MAX_NESTED_EXCEPTION_LEVEL = 100;
@@ -124,8 +122,8 @@ public void setVersion(Version version) {
     }
 
     /**
-     * Test if the stream has the specified feature. Features are used when serializing {@link ClusterState.Custom} or
-     * {@link Metadata.Custom}; see also {@link ClusterState.FeatureAware}.
+     * Test if the stream has the specified feature. Features are used when serializing {@code ClusterState.Custom} or
+     * {@code Metadata.Custom}; see also {@code ClusterState.FeatureAware}.
      *
      * @param feature the feature to test
      * @return true if the stream has the specified feature
@@ -326,7 +324,7 @@ public void writeOptionalVLong(@Nullable Long l) throws IOException {
      * Writes a long in a variable-length format without first checking if it is negative. Package private for testing. Use
      * {@link #writeVLong(long)} instead.
      */
-    void writeVLongNoCheck(long i) throws IOException {
+    public void writeVLongNoCheck(long i) throws IOException {
         final byte[] buffer = scratch.get();
         int index = 0;
         while ((i & ~0x7F) != 0) {
@@ -495,6 +493,10 @@ public void writeOptionalDouble(@Nullable Double v) throws IOException {
         }
     }
 
+    public final void writeBigInteger(BigInteger v) throws IOException {
+        writeString(v.toString());
+    }
+
     private static byte ZERO = 0;
     private static byte ONE = 1;
     private static byte TWO = 2;
@@ -638,28 +640,6 @@ public final <K, V> void writeMap(final Map<K, V> map, final Writer<K> keyWriter
         }
     }
 
-    /**
-     * Write a {@link ImmutableOpenMap} of {@code K}-type keys to {@code V}-type.
-     *
-     * @param keyWriter The key writer
-     * @param valueWriter The value writer
-     */
-    public final <K, V> void writeMap(final ImmutableOpenMap<K, V> map, final Writer<K> keyWriter, final Writer<V> valueWriter)
-        throws IOException {
-        writeVInt(map.size());
-        for (final ObjectObjectCursor<K, V> entry : map) {
-            keyWriter.write(this, entry.key);
-            valueWriter.write(this, entry.value);
-        }
-    }
-
-    /**
-     * Write a {@link ImmutableOpenMap} of {@code K}-type keys to {@code V}-type.
-     */
-    public final <K extends Writeable, V extends Writeable> void writeMap(final ImmutableOpenMap<K, V> map) throws IOException {
-        writeMap(map, (o, k) -> k.writeTo(o), (o, v) -> v.writeTo(o));
-    }
-
     /**
      * Writes an {@link Instant} to the stream with nanosecond resolution
      */
@@ -680,10 +660,10 @@ public final void writeOptionalInstant(@Nullable Instant instant) throws IOExcep
         }
     }
 
-    private static final Map<Class<?>, Writer> WRITERS;
+    private static final Map<Class<?>, Writer<Object>> WRITERS;
 
     static {
-        Map<Class<?>, Writer> writers = new HashMap<>();
+        Map<Class<?>, Writer<Object>> writers = new HashMap<>();
         writers.put(String.class, (o, v) -> {
             o.writeByte((byte) 0);
             o.writeString((String) v);
@@ -716,6 +696,7 @@ public final void writeOptionalInstant(@Nullable Instant instant) throws IOExcep
         });
         writers.put(List.class, (o, v) -> {
             o.writeByte((byte) 7);
+            @SuppressWarnings("rawtypes")
             final List list = (List) v;
             o.writeVInt(list.size());
             for (Object item : list) {
@@ -752,12 +733,6 @@ public final void writeOptionalInstant(@Nullable Instant instant) throws IOExcep
             o.writeByte((byte) 12);
             o.writeLong(((Date) v).getTime());
         });
-        writers.put(ReadableInstant.class, (o, v) -> {
-            o.writeByte((byte) 13);
-            final ReadableInstant instant = (ReadableInstant) v;
-            o.writeString(instant.getZone().getID());
-            o.writeLong(instant.getMillis());
-        });
         writers.put(BytesReference.class, (o, v) -> {
             o.writeByte((byte) 14);
             o.writeBytesReference((BytesReference) v);
@@ -790,25 +765,12 @@ public final void writeOptionalInstant(@Nullable Instant instant) throws IOExcep
             o.writeByte((byte) 21);
             o.writeBytesRef((BytesRef) v);
         });
-        writers.put(GeoPoint.class, (o, v) -> {
-            o.writeByte((byte) 22);
-            o.writeGeoPoint((GeoPoint) v);
-        });
         writers.put(ZonedDateTime.class, (o, v) -> {
             o.writeByte((byte) 23);
             final ZonedDateTime zonedDateTime = (ZonedDateTime) v;
             o.writeString(zonedDateTime.getZone().getId());
             o.writeLong(zonedDateTime.toInstant().toEpochMilli());
         });
-        writers.put(JodaCompatibleZonedDateTime.class, (o, v) -> {
-            // write the joda compatibility datetime as joda datetime
-            o.writeByte((byte) 13);
-            final JodaCompatibleZonedDateTime zonedDateTime = (JodaCompatibleZonedDateTime) v;
-            String zoneId = zonedDateTime.getZonedDateTime().getZone().getId();
-            // joda does not understand "Z" for utc, so we must special case
-            o.writeString(zoneId.equals("Z") ? DateTimeZone.UTC.getID() : zoneId);
-            o.writeLong(zonedDateTime.toInstant().toEpochMilli());
-        });
         writers.put(Set.class, (o, v) -> {
             if (v instanceof LinkedHashSet) {
                 o.writeByte((byte) 24);
@@ -826,7 +788,10 @@ public final void writeOptionalInstant(@Nullable Instant instant) throws IOExcep
     }
 
     private static Class<?> getGenericType(Object value) {
-        if (value instanceof List) {
+        Class<?> registeredClass = WriteableRegistry.getCustomClassFromInstance(value);
+        if (registeredClass != null) {
+            return registeredClass;
+        } else if (value instanceof List) {
             return List.class;
         } else if (value instanceof Object[]) {
             return Object[].class;
@@ -834,8 +799,6 @@ private static Class<?> getGenericType(Object value) {
             return Map.class;
         } else if (value instanceof Set) {
             return Set.class;
-        } else if (value instanceof ReadableInstant) {
-            return ReadableInstant.class;
         } else if (value instanceof BytesReference) {
             return BytesReference.class;
         } else {
@@ -843,6 +806,23 @@ private static Class<?> getGenericType(Object value) {
         }
     }
 
+    /**
+     * Returns the registered writer for the given class type.
+     */
+    @SuppressWarnings("unchecked")
+    public static <W extends Writer<?>> W getWriter(Class<?> type) {
+        Writer<Object> writer = WriteableRegistry.getWriter(type);
+        if (writer == null) {
+            // fallback to this local hashmap
+            // todo: move all writers to the registry
+            writer = WRITERS.get(type);
+        }
+        if (writer == null) {
+            throw new IllegalArgumentException("can not write type [" + type + "]");
+        }
+        return (W) writer;
+    }
+
     /**
      * Notice: when serialization a map, the stream out map with the stream in map maybe have the
      * different key-value orders, they will maybe have different stream order.
@@ -855,12 +835,8 @@ public void writeGenericValue(@Nullable Object value) throws IOException {
             return;
         }
         final Class<?> type = getGenericType(value);
-        final Writer writer = WRITERS.get(type);
-        if (writer != null) {
-            writer.write(this, value);
-        } else {
-            throw new IllegalArgumentException("can not write type [" + type + "]");
-        }
+        final Writer<Object> writer = getWriter(type);
+        writer.write(this, value);
     }
 
     public static void checkWriteable(@Nullable Object value) throws IllegalArgumentException {
@@ -1120,7 +1096,25 @@ private void writeException(Throwable rootException, Throwable throwable, int ne
         }
     }
 
-    boolean failOnTooManyNestedExceptions(Throwable throwable) {
+    /** Writes the OpenSearch {@link Version} to the output stream */
+    public void writeVersion(final Version version) throws IOException {
+        writeVInt(version.id);
+    }
+
+    /** Writes the OpenSearch {@link Build} informn to the output stream */
+    public void writeBuild(final Build build) throws IOException {
+        // the following is new for opensearch: we write the distribution name to support any "forks" of the code
+        writeString(build.getDistribution());
+
+        final Build.Type buildType = build.type();
+        writeString(buildType.displayName());
+        writeString(build.hash());
+        writeString(build.date());
+        writeBoolean(build.isSnapshot());
+        writeString(build.getQualifiedVersion());
+    }
+
+    protected boolean failOnTooManyNestedExceptions(Throwable throwable) {
         throw new AssertionError("too many nested exceptions", throwable);
     }
 
@@ -1144,21 +1138,6 @@ public void writeOptionalNamedWriteable(@Nullable NamedWriteable namedWriteable)
         }
     }
 
-    /**
-     * Writes the given {@link GeoPoint} to the stream
-     */
-    public void writeGeoPoint(GeoPoint geoPoint) throws IOException {
-        writeDouble(geoPoint.lat());
-        writeDouble(geoPoint.lon());
-    }
-
-    /**
-     * Write a {@linkplain DateTimeZone} to the stream.
-     */
-    public void writeTimeZone(DateTimeZone timeZone) throws IOException {
-        writeString(timeZone.getID());
-    }
-
     /**
      * Write a {@linkplain ZoneId} to the stream.
      */
@@ -1166,18 +1145,6 @@ public void writeZoneId(ZoneId timeZone) throws IOException {
         writeString(timeZone.getId());
     }
 
-    /**
-     * Write an optional {@linkplain DateTimeZone} to the stream.
-     */
-    public void writeOptionalTimeZone(@Nullable DateTimeZone timeZone) throws IOException {
-        if (timeZone == null) {
-            writeBoolean(false);
-        } else {
-            writeBoolean(true);
-            writeTimeZone(timeZone);
-        }
-    }
-
     /**
      * Write an optional {@linkplain ZoneId} to the stream.
      */
diff --git a/server/src/main/java/org/opensearch/common/io/stream/VersionedNamedWriteable.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/VersionedNamedWriteable.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/io/stream/VersionedNamedWriteable.java
rename to libs/core/src/main/java/org/opensearch/core/common/io/stream/VersionedNamedWriteable.java
index 6ce224c8e218a..e7124e44692be 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/VersionedNamedWriteable.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/VersionedNamedWriteable.java
@@ -30,12 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.opensearch.Version;
 
 /**
  * A {@link NamedWriteable} that has a minimum version associated with it.
+ *
+ * @opensearch.internal
  */
 public interface VersionedNamedWriteable extends NamedWriteable {
 
diff --git a/libs/core/src/main/java/org/opensearch/core/common/io/stream/Writeable.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/Writeable.java
new file mode 100644
index 0000000000000..af9df51655414
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/Writeable.java
@@ -0,0 +1,175 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.common.io.stream;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Implementers can be written to a {@linkplain StreamOutput} and read from a {@linkplain StreamInput}. This allows them to be "thrown
+ * across the wire" using OpenSearch's internal protocol. If the implementer also implements equals and hashCode then a copy made by
+ * serializing and deserializing must be equal and have the same hashCode. It isn't required that such a copy be entirely unchanged.
+ *
+ * @opensearch.internal
+ */
+public interface Writeable {
+    /**
+     * A WriteableRegistry registers {@link Writer} methods for writing data types over a
+     * {@link StreamOutput} channel and {@link Reader} methods for reading data from a
+     * {@link StreamInput} channel.
+     *
+     * @opensearch.internal
+     */
+    class WriteableRegistry {
+        private static final Map<Class<?>, Writer<?>> WRITER_REGISTRY = new ConcurrentHashMap<>();
+        private static final Map<Class<?>, Class<?>> WRITER_CUSTOM_CLASS_MAP = new ConcurrentHashMap<>();
+        private static final Map<Byte, Reader<?>> READER_REGISTRY = new ConcurrentHashMap<>();
+
+        /**
+         * registers a streamable writer
+         *
+         * @opensearch.internal
+         */
+        public static <W extends Writer<?>> void registerWriter(final Class<?> clazz, final W writer) {
+            if (WRITER_REGISTRY.putIfAbsent(clazz, writer) != null) {
+                throw new IllegalArgumentException("Streamable writer already registered for type [" + clazz.getName() + "]");
+            }
+        }
+
+        /**
+         * registers a streamable reader
+         *
+         * @opensearch.internal
+         */
+        public static <R extends Reader<?>> void registerReader(final byte ordinal, final R reader) {
+            if (READER_REGISTRY.putIfAbsent(ordinal, reader) != null) {
+                throw new IllegalArgumentException("Streamable reader already registered for ordinal [" + (int) ordinal + "]");
+            }
+        }
+
+        public static void registerClassAlias(final Class<?> classInstance, final Class<?> classGeneric) {
+            if (WRITER_CUSTOM_CLASS_MAP.putIfAbsent(classInstance, classGeneric) != null) {
+                throw new IllegalArgumentException("Streamable custom class already registered [" + classInstance.getClass() + "]");
+            }
+        }
+
+        /**
+         * Returns the registered writer keyed by the class type
+         */
+        @SuppressWarnings("unchecked")
+        public static <W extends Writer<?>> W getWriter(final Class<?> clazz) {
+            return (W) WRITER_REGISTRY.get(clazz);
+        }
+
+        /**
+         * Returns the ristered reader keyed by the unique ordinal
+         */
+        @SuppressWarnings("unchecked")
+        public static <R extends Reader<?>> R getReader(final byte b) {
+            return (R) READER_REGISTRY.get(b);
+        }
+
+        public static Class<?> getCustomClassFromInstance(final Object value) {
+            if (value == null) {
+                throw new IllegalArgumentException("Attempting to retrieve a class type from a null value");
+            }
+            // rip through registered classes; return the class iff 'value' is an instance
+            // we do it this way to cover inheritance and interfaces (e.g., joda DateTime is an instanceof
+            // a ReadableInstant interface)
+            for (final Class<?> clazz : WRITER_CUSTOM_CLASS_MAP.values()) {
+                if (clazz.isInstance(value)) {
+                    return clazz;
+                }
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Write this into the {@linkplain StreamOutput}.
+     */
+    void writeTo(StreamOutput out) throws IOException;
+
+    /**
+     * Reference to a method that can write some object to a {@link StreamOutput}.
+     * <p>
+     * By convention this is a method from {@link StreamOutput} itself (e.g., {@code StreamOutput#writeString}). If the value can be
+     * {@code null}, then the "optional" variant of methods should be used!
+     * <p>
+     * Most classes should implement {@code Writeable} and the {@code Writeable#writeTo(StreamOutput)} method should <em>use</em>
+     * {@link StreamOutput} methods directly or this indirectly:
+     * <pre><code>
+     * public void writeTo(StreamOutput out) throws IOException {
+     *     out.writeVInt(someValue);
+     *     out.writeMapOfLists(someMap, StreamOutput::writeString, StreamOutput::writeString);
+     * }
+     * </code></pre>
+     */
+    @FunctionalInterface
+    interface Writer<V> {
+
+        /**
+         * Write {@code V}-type {@code value} to the {@code out}put stream.
+         *
+         * @param out Output to write the {@code value} too
+         * @param value The value to add
+         */
+        void write(final StreamOutput out, V value) throws IOException;
+    }
+
+    /**
+     * Reference to a method that can read some object from a stream. By convention this is a constructor that takes
+     * {@linkplain StreamInput} as an argument for most classes and a static method for things like enums. Returning null from one of these
+     * is always wrong - for that we use methods like {@code StreamInput#readOptionalWriteable(Reader)}.
+     * <p>
+     * As most classes will implement this via a constructor (or a static method in the case of enumerations), it's something that should
+     * look like:
+     * <pre><code>
+     * public MyClass(final StreamInput in) throws IOException {
+     *     this.someValue = in.readVInt();
+     *     this.someMap = in.readMapOfLists(StreamInput::readString, StreamInput::readString);
+     * }
+     * </code></pre>
+     */
+    @FunctionalInterface
+    interface Reader<V> {
+
+        /**
+         * Read {@code V}-type value from a stream.
+         *
+         * @param in Input to read the value from
+         */
+        V read(final StreamInput in) throws IOException;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/common/io/stream/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/io/stream/package-info.java
new file mode 100644
index 0000000000000..371f7ff7dd7b4
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/io/stream/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core transport stream classes */
+package org.opensearch.core.common.io.stream;
diff --git a/server/src/main/java/org/opensearch/common/logging/LoggerMessageFormat.java b/libs/core/src/main/java/org/opensearch/core/common/logging/LoggerMessageFormat.java
similarity index 82%
rename from server/src/main/java/org/opensearch/common/logging/LoggerMessageFormat.java
rename to libs/core/src/main/java/org/opensearch/core/common/logging/LoggerMessageFormat.java
index a81e2a4fc479f..0560fc5c7b7e9 100644
--- a/server/src/main/java/org/opensearch/common/logging/LoggerMessageFormat.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/logging/LoggerMessageFormat.java
@@ -30,13 +30,19 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.logging;
+package org.opensearch.core.common.logging;
 
 import java.util.HashSet;
 import java.util.Set;
 
 /**
  * Format string for OpenSearch log messages.
+ * <p>
+ * This class is almost a copy of {@code org.slf4j.helpers.MessageFormatter}<p>
+ * The original code is licensed under the MIT License and is available at :
+ * <a href="https://github.com/qos-ch/slf4j/blob/7c164fab8d54f823dd55c01a5a839c153f578297/slf4j-api/src/main/java/org/slf4j/helpers/MessageFormatter.java">MessageFormatter.java</a>
+ *
+ * @opensearch.internal
  */
 public class LoggerMessageFormat {
 
@@ -49,6 +55,17 @@ public static String format(final String messagePattern, final Object... argArra
         return format(null, messagePattern, argArray);
     }
 
+    /**
+     * (this is almost a copy of {@code org.slf4j.helpers.MessageFormatter.arrayFormat})
+     *
+     * @param prefix the prefix to prepend to the formatted message (can be null)
+     * @param messagePattern the message pattern which will be parsed and formatted
+     * @param argArray an array of arguments to be substituted in place of formatting anchors
+     * @return null if messagePattern is null <p>
+     *         messagePattern if argArray is (null or empty) and prefix is null <p>
+     *         prefix + messagePattern if argArray is (null or empty) and prefix is not null <p>
+     *         formatted message otherwise (even if prefix is null)
+     */
     public static String format(final String prefix, final String messagePattern, final Object... argArray) {
         if (messagePattern == null) {
             return null;
@@ -108,6 +125,13 @@ public static String format(final String prefix, final String messagePattern, fi
         return sbuf.toString();
     }
 
+    /**
+     * Checks if (delimterStartIndex - 1) in messagePattern is an escape character.
+     * @param messagePattern the message pattern
+     * @param delimiterStartIndex the index of the character to check
+     * @return true if there is an escape char before the character at delimiterStartIndex.<p>
+     *         Always returns false if delimiterStartIndex == 0 (edge case)
+     */
     static boolean isEscapedDelimiter(String messagePattern, int delimiterStartIndex) {
 
         if (delimiterStartIndex == 0) {
@@ -121,6 +145,13 @@ static boolean isEscapedDelimiter(String messagePattern, int delimiterStartIndex
         }
     }
 
+    /**
+     * Checks if (delimterStartIndex - 2) in messagePattern is an escape character.
+     * @param messagePattern the message pattern
+     * @param delimiterStartIndex the index of the character to check
+     * @return true if (delimterStartIndex - 2) in messagePattern is an escape character.
+     *         Always returns false if delimiterStartIndex is less than 2 (edge case)
+     */
     static boolean isDoubleEscaped(String messagePattern, int delimiterStartIndex) {
         if (delimiterStartIndex >= 2 && messagePattern.charAt(delimiterStartIndex - 2) == ESCAPE_CHAR) {
             return true;
diff --git a/libs/core/src/main/java/org/opensearch/core/common/logging/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/logging/package-info.java
new file mode 100644
index 0000000000000..b3094b1e2782c
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/logging/package-info.java
@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** core logging classes */
+package org.opensearch.core.common.logging;
diff --git a/libs/core/src/main/java/org/opensearch/core/common/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/package-info.java
new file mode 100644
index 0000000000000..b5cf352aa5495
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** common core classes that require third party dependencies */
+package org.opensearch.core.common;
diff --git a/server/src/main/java/org/opensearch/common/settings/SecureString.java b/libs/core/src/main/java/org/opensearch/core/common/settings/SecureString.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/settings/SecureString.java
rename to libs/core/src/main/java/org/opensearch/core/common/settings/SecureString.java
index 83c6fbb78c976..322300a554284 100644
--- a/server/src/main/java/org/opensearch/common/settings/SecureString.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/settings/SecureString.java
@@ -30,7 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.settings;
+package org.opensearch.core.common.settings;
+
+import org.opensearch.common.annotation.PublicApi;
 
 import java.io.Closeable;
 import java.util.Arrays;
@@ -38,7 +40,10 @@
 
 /**
  * A String implementations which allows clearing the underlying char array.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class SecureString implements CharSequence, Closeable {
 
     private char[] chars;
diff --git a/libs/core/src/main/java/org/opensearch/core/common/settings/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/settings/package-info.java
new file mode 100644
index 0000000000000..a2588a4633417
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/settings/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core Settings module */
+package org.opensearch.core.common.settings;
diff --git a/server/src/main/java/org/opensearch/common/text/Text.java b/libs/core/src/main/java/org/opensearch/core/common/text/Text.java
similarity index 93%
rename from server/src/main/java/org/opensearch/common/text/Text.java
rename to libs/core/src/main/java/org/opensearch/core/common/text/Text.java
index 6756fa8a001f0..ca5402edae59e 100644
--- a/server/src/main/java/org/opensearch/common/text/Text.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/text/Text.java
@@ -29,13 +29,13 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.text;
+package org.opensearch.core.common.text;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -43,6 +43,8 @@
 /**
  * Both {@link String} and {@link BytesReference} representation of the text. Starts with one of those, and if
  * the other is requests, caches the other one in a local reference so no additional conversion will be needed.
+ *
+ * @opensearch.internal
  */
 public final class Text implements Comparable<Text>, ToXContentFragment {
 
diff --git a/libs/core/src/main/java/org/opensearch/core/common/text/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/text/package-info.java
new file mode 100644
index 0000000000000..02abc5835c84f
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/text/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core text module */
+package org.opensearch.core.common.text;
diff --git a/server/src/main/java/org/opensearch/common/transport/BoundTransportAddress.java b/libs/core/src/main/java/org/opensearch/core/common/transport/BoundTransportAddress.java
similarity index 93%
rename from server/src/main/java/org/opensearch/common/transport/BoundTransportAddress.java
rename to libs/core/src/main/java/org/opensearch/core/common/transport/BoundTransportAddress.java
index a6aae5674615b..8908a172395f2 100644
--- a/server/src/main/java/org/opensearch/common/transport/BoundTransportAddress.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/transport/BoundTransportAddress.java
@@ -30,12 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.transport;
+package org.opensearch.core.common.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.network.InetAddresses;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -43,6 +43,8 @@
  * A bounded transport address is a tuple of {@link TransportAddress}, one array that represents
  * the addresses the transport is bound to, and the other is the published one that represents the address clients
  * should communicate on.
+ *
+ * @opensearch.internal
  */
 public class BoundTransportAddress implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/common/transport/TransportAddress.java b/libs/core/src/main/java/org/opensearch/core/common/transport/TransportAddress.java
similarity index 84%
rename from server/src/main/java/org/opensearch/common/transport/TransportAddress.java
rename to libs/core/src/main/java/org/opensearch/core/common/transport/TransportAddress.java
index 3efdfb1f97681..551504ed6f719 100644
--- a/server/src/main/java/org/opensearch/common/transport/TransportAddress.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/transport/TransportAddress.java
@@ -30,14 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.transport;
+package org.opensearch.core.common.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.network.NetworkAddress;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -46,6 +46,8 @@
 
 /**
  * A transport address used for IP socket address (wraps {@link java.net.InetSocketAddress}).
+ *
+ * @opensearch.internal
  */
 public final class TransportAddress implements Writeable, ToXContentFragment {
 
@@ -69,6 +71,12 @@ public TransportAddress(InetAddress address, int port) {
         this(new InetSocketAddress(address, port));
     }
 
+    /**
+     * Creates a new {@link TransportAddress} from a {@link InetSocketAddress}.
+     * @param address the address to wrap
+     * @throws IllegalArgumentException if the address is null or not resolved
+     * @see InetSocketAddress#getAddress()
+     */
     public TransportAddress(InetSocketAddress address) {
         if (address == null) {
             throw new IllegalArgumentException("InetSocketAddress must not be null");
@@ -80,7 +88,9 @@ public TransportAddress(InetSocketAddress address) {
     }
 
     /**
-     * Read from a stream.
+     * Creates a new {@link TransportAddress} from a {@link StreamInput}.
+     * @param in the stream to read from
+     * @throws IOException if an I/O error occurs
      */
     public TransportAddress(StreamInput in) throws IOException {
         final int len = in.readByte();
@@ -114,6 +124,8 @@ public String getAddress() {
 
     /**
      * Returns the addresses port
+     * @return the port number, or 0 if the socket is not bound yet.
+     * @see InetSocketAddress#getPort()
      */
     public int getPort() {
         return address.getPort();
diff --git a/libs/core/src/main/java/org/opensearch/core/common/transport/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/transport/package-info.java
new file mode 100644
index 0000000000000..21d2abfce958a
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/transport/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common / Base Transport classes used to implement the OpenSearch transport layer */
+package org.opensearch.core.common.transport;
diff --git a/server/src/main/java/org/opensearch/common/unit/ByteSizeUnit.java b/libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeUnit.java
similarity index 94%
rename from server/src/main/java/org/opensearch/common/unit/ByteSizeUnit.java
rename to libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeUnit.java
index 1552833fe5694..c15db75d06d49 100644
--- a/server/src/main/java/org/opensearch/common/unit/ByteSizeUnit.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeUnit.java
@@ -30,11 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.unit;
+package org.opensearch.core.common.unit;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -44,7 +45,17 @@
  * A {@code SizeUnit} does not maintain size information, but only
  * helps organize and use size representations that may be maintained
  * separately across various contexts.
+ *
+ * It use conventional data storage values (base-2) :
+ * <ul>
+ *     <li>1KB = 1024 bytes</li>
+ *     <li>1MB = 1024KB</li>
+ *     <li> ... </li>
+ * </ul>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public enum ByteSizeUnit implements Writeable {
     BYTES {
         @Override
diff --git a/server/src/main/java/org/opensearch/common/unit/ByteSizeValue.java b/libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeValue.java
similarity index 86%
rename from server/src/main/java/org/opensearch/common/unit/ByteSizeValue.java
rename to libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeValue.java
index 4f58abc64e495..1ed6d2d204a99 100644
--- a/server/src/main/java/org/opensearch/common/unit/ByteSizeValue.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/unit/ByteSizeValue.java
@@ -30,34 +30,29 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.unit;
+package org.opensearch.core.common.unit;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.logging.LogConfigurator;
-import org.opensearch.common.network.NetworkService;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * A byte size value
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class ByteSizeValue implements Writeable, Comparable<ByteSizeValue>, ToXContentFragment {
 
-    /**
-     * We have to lazy initialize the deprecation logger as otherwise a static logger here would be constructed before logging is configured
-     * leading to a runtime failure (see {@link LogConfigurator#checkErrorListener()} ). The premature construction would come from any
-     * {@link ByteSizeValue} object constructed in, for example, settings in {@link NetworkService}.
-     */
-    static class DeprecationLoggerHolder {
-        static DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(ByteSizeValue.class);
-    }
-
     public static final ByteSizeValue ZERO = new ByteSizeValue(0, ByteSizeUnit.BYTES);
 
     private final long size;
@@ -255,14 +250,14 @@ private static ByteSizeValue parse(
                 return new ByteSizeValue(Long.parseLong(s), unit);
             } catch (final NumberFormatException e) {
                 try {
-                    final double doubleValue = Double.parseDouble(s);
-                    DeprecationLoggerHolder.deprecationLogger.deprecate(
-                        "fractional_byte_values",
-                        "Fractional bytes values are deprecated. Use non-fractional bytes values instead: [{}] found for setting [{}]",
+                    Double.parseDouble(s);
+                    throw new OpenSearchParseException(
+                        "Failed to parse bytes value [{}]. Fractional bytes values have been "
+                            + "deprecated since Legacy 6.2. Use non-fractional bytes values instead: found for setting [{}]",
+                        e,
                         initialInput,
                         settingName
                     );
-                    return new ByteSizeValue((long) (doubleValue * unit.toBytes(1)));
                 } catch (final NumberFormatException ignored) {
                     throw new OpenSearchParseException("failed to parse [{}]", e, initialInput);
                 }
diff --git a/libs/core/src/main/java/org/opensearch/core/common/unit/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/unit/package-info.java
new file mode 100644
index 0000000000000..79b5dcdcba3b6
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/unit/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Common units of measurement used by the core library. These units of measurement classes exist
+ * in the core because they depend on core functionality beyond the common library (e.g., serializable).
+ *
+ * @opensearch.api
+ * @opensearch.experimental
+ */
+package org.opensearch.core.common.unit;
diff --git a/server/src/main/java/org/opensearch/common/util/BigArray.java b/libs/core/src/main/java/org/opensearch/core/common/util/BigArray.java
similarity index 92%
rename from server/src/main/java/org/opensearch/common/util/BigArray.java
rename to libs/core/src/main/java/org/opensearch/core/common/util/BigArray.java
index c71b3da9ef14c..eafefa38bc061 100644
--- a/server/src/main/java/org/opensearch/common/util/BigArray.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/util/BigArray.java
@@ -30,12 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.util;
+package org.opensearch.core.common.util;
 
 import org.apache.lucene.util.Accountable;
 import org.opensearch.common.lease.Releasable;
 
-/** Base abstraction of an array. */
+/**
+ * Base abstraction of an array.
+ *
+ * @opensearch.internal
+ */
 public interface BigArray extends Releasable, Accountable {
 
     /** Return the length of this array. */
diff --git a/server/src/main/java/org/opensearch/common/util/ByteArray.java b/libs/core/src/main/java/org/opensearch/core/common/util/ByteArray.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/util/ByteArray.java
rename to libs/core/src/main/java/org/opensearch/core/common/util/ByteArray.java
index 0b360148ddc01..e50f24417f8bc 100644
--- a/server/src/main/java/org/opensearch/common/util/ByteArray.java
+++ b/libs/core/src/main/java/org/opensearch/core/common/util/ByteArray.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.util;
+package org.opensearch.core.common.util;
 
 import org.apache.lucene.util.BytesRef;
 
@@ -38,6 +38,8 @@
 
 /**
  * Abstraction of an array of byte values.
+ *
+ * @opensearch.internal
  */
 public interface ByteArray extends BigArray {
 
diff --git a/libs/core/src/main/java/org/opensearch/core/common/util/CollectionUtils.java b/libs/core/src/main/java/org/opensearch/core/common/util/CollectionUtils.java
new file mode 100644
index 0000000000000..5335c98182b64
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/util/CollectionUtils.java
@@ -0,0 +1,351 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.common.util;
+
+import org.opensearch.common.collect.Iterators;
+import org.opensearch.core.common.Strings;
+
+import java.nio.file.Path;
+import java.util.AbstractList;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.RandomAccess;
+import java.util.Set;
+
+/**
+ * Collections-related utility methods.
+ *
+ * @opensearch.internal
+ */
+public class CollectionUtils {
+
+    /**
+     * Checks if the given array contains any elements.
+     *
+     * @param array The array to check
+     *
+     * @return false if the array contains an element, true if not or the array is null.
+     */
+    public static boolean isEmpty(Object[] array) {
+        return array == null || array.length == 0;
+    }
+
+    /**
+     * Return a rotated view of the given list with the given distance.
+     * <ul>
+     * <li>The distance can be negative, in which case the list is rotated to the left.</li>
+     * <li>The distance can be larger than the size of the list, in which case the list is rotated multiple times.</li>
+     * <li>The distance can be zero, in which case the list is not rotated.</li>
+     * <li>The list can be empty, in which case it remains empty.</li>
+     * </ul>
+     * @param list the list to rotate
+     * @param distance the distance to rotate (positive rotates right, negative rotates left)
+     * @return a rotated view of the given list with the given distance
+     * @see RotatedList
+     */
+    public static <T> List<T> rotate(final List<T> list, int distance) {
+        if (list.isEmpty()) {
+            return list;
+        }
+
+        int d = distance % list.size();
+        if (d < 0) {
+            d += list.size();
+        }
+
+        if (d == 0) {
+            return list;
+        }
+
+        return new RotatedList<>(list, d);
+    }
+
+    /**
+     * In place de-duplicates items in a list
+     * Noop if the list is empty or has one item.
+     *
+     * @throws NullPointerException if the list is `null` or comparator is `null`
+     * @param array the list to de-duplicate
+     * @param comparator the comparator to use to compare items
+     * @param <T> the type of the items in the list
+     */
+    public static <T> void sortAndDedup(final List<T> array, Comparator<T> comparator) {
+        // base case: one item
+        if (array.size() <= 1) {
+            return;
+        }
+        array.sort(comparator);
+        ListIterator<T> deduped = array.listIterator();
+        T cmp = deduped.next(); // return the first item and advance
+        Iterator<T> oldArray = array.iterator();
+        oldArray.next(); // advance to the old to the second item (advanced to third below)
+
+        do {
+            T old = oldArray.next(); // get the next item and advance iter
+            if (comparator.compare(cmp, old) != 0 && (cmp = deduped.next()) != old) {
+                deduped.set(old);
+            }
+        } while (oldArray.hasNext());
+        // in place update
+        array.subList(deduped.nextIndex(), array.size()).clear();
+    }
+
+    /**
+     * Converts a collection of Integers to an array of ints.
+     * @param ints The collection of Integers to convert
+     * @return The array of ints
+     * @throws NullPointerException if ints is null
+     */
+    public static int[] toArray(Collection<Integer> ints) {
+        Objects.requireNonNull(ints);
+        return ints.stream().mapToInt(s -> s).toArray();
+    }
+
+    /**
+     * Deeply inspects a Map, Iterable, or Object array looking for references back to itself.
+     * @throws IllegalArgumentException if a self-reference is found
+     * @param value The object to evaluate looking for self references
+     * @param messageHint A string to be included in the exception message if the call fails, to provide
+     *                    more context to the handler of the exception
+     */
+    public static void ensureNoSelfReferences(Object value, String messageHint) {
+        Iterable<?> it = convert(value);
+        if (it != null) {
+            ensureNoSelfReferences(it, value, Collections.newSetFromMap(new IdentityHashMap<>()), messageHint);
+        }
+    }
+
+    /**
+     * Converts an object to an Iterable, if possible.
+     * @param value The object to convert
+     * @return The Iterable, or null if the object cannot be converted
+     */
+    @SuppressWarnings("unchecked")
+    private static Iterable<?> convert(Object value) {
+        if (value == null) {
+            return null;
+        }
+        if (value instanceof Map) {
+            Map<?, ?> map = (Map<?, ?>) value;
+            return () -> Iterators.concat(map.keySet().iterator(), map.values().iterator());
+        } else if ((value instanceof Iterable) && (value instanceof Path == false)) {
+            return (Iterable<?>) value;
+        } else if (value instanceof Object[]) {
+            return Arrays.asList((Object[]) value);
+        } else {
+            return null;
+        }
+    }
+
+    private static void ensureNoSelfReferences(
+        final Iterable<?> value,
+        Object originalReference,
+        final Set<Object> ancestors,
+        String messageHint
+    ) {
+        if (value != null) {
+            if (ancestors.add(originalReference) == false) {
+                String suffix = Strings.isNullOrEmpty(messageHint) ? "" : String.format(Locale.ROOT, " (%s)", messageHint);
+                throw new IllegalArgumentException("Iterable object is self-referencing itself" + suffix);
+            }
+            for (Object o : value) {
+                ensureNoSelfReferences(convert(o), o, ancestors, messageHint);
+            }
+            ancestors.remove(originalReference);
+        }
+    }
+
+    /**
+     * Returns an unmodifiable copy of the given map.
+     * @param map Map to copy
+     * @return unmodifiable copy of the map
+     */
+    public static <R, T> Map<R, T> copyMap(Map<R, T> map) {
+        if (map.isEmpty()) {
+            return Collections.emptyMap();
+        } else {
+            return Collections.unmodifiableMap(new HashMap<>(map));
+        }
+    }
+
+    /**
+     * A rotated list
+     *
+     * @opensearch.internal
+     */
+    private static class RotatedList<T> extends AbstractList<T> implements RandomAccess {
+
+        private final List<T> in;
+        private final int distance;
+
+        /**
+         * Creates a rotated list
+         * @param list The list to rotate
+         * @param distance The distance to rotate to the right
+         * @throws IllegalArgumentException if the distance is negative or greater than the size of the list;
+         *                                  or if the list is not a {@link RandomAccess} list
+         */
+        RotatedList(List<T> list, int distance) {
+            if (distance < 0 || distance >= list.size()) {
+                throw new IllegalArgumentException();
+            }
+            if (!(list instanceof RandomAccess)) {
+                throw new IllegalArgumentException();
+            }
+            this.in = list;
+            this.distance = distance;
+        }
+
+        @Override
+        public T get(int index) {
+            int idx = distance + index;
+            if (idx < 0 || idx >= in.size()) {
+                idx -= in.size();
+            }
+            return in.get(idx);
+        }
+
+        @Override
+        public int size() {
+            return in.size();
+        }
+    }
+
+    /**
+     * Converts an {@link Iterable} to an {@link ArrayList}.
+     * @param elements The iterable to convert
+     * @param <E> the type the elements
+     * @return an {@link ArrayList}
+     * @throws NullPointerException if elements is null
+     */
+    @SuppressWarnings("unchecked")
+    public static <E> ArrayList<E> iterableAsArrayList(Iterable<? extends E> elements) {
+        if (elements == null) {
+            throw new NullPointerException("elements");
+        }
+        if (elements instanceof Collection) {
+            return new ArrayList<>((Collection) elements);
+        } else {
+            ArrayList<E> list = new ArrayList<>();
+            for (E element : elements) {
+                list.add(element);
+            }
+            return list;
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <E> ArrayList<E> arrayAsArrayList(E... elements) {
+        if (elements == null) {
+            throw new NullPointerException("elements");
+        }
+        return new ArrayList<>(Arrays.asList(elements));
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <E> ArrayList<E> asArrayList(E first, E... other) {
+        if (other == null) {
+            throw new NullPointerException("other");
+        }
+        ArrayList<E> list = new ArrayList<>(1 + other.length);
+        list.add(first);
+        list.addAll(Arrays.asList(other));
+        return list;
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <E> ArrayList<E> asArrayList(E first, E second, E... other) {
+        if (other == null) {
+            throw new NullPointerException("other");
+        }
+        ArrayList<E> list = new ArrayList<>(1 + 1 + other.length);
+        list.add(first);
+        list.add(second);
+        list.addAll(Arrays.asList(other));
+        return list;
+    }
+
+    public static <E> ArrayList<E> newSingletonArrayList(E element) {
+        return new ArrayList<>(Collections.singletonList(element));
+    }
+
+    public static <E> List<List<E>> eagerPartition(List<E> list, int size) {
+        if (list == null) {
+            throw new NullPointerException("list");
+        }
+        if (size <= 0) {
+            throw new IllegalArgumentException("size <= 0");
+        }
+        List<List<E>> result = new ArrayList<>((int) Math.ceil(list.size() / size));
+
+        List<E> accumulator = new ArrayList<>(size);
+        int count = 0;
+        for (E element : list) {
+            if (count == size) {
+                result.add(accumulator);
+                accumulator = new ArrayList<>(size);
+                count = 0;
+            }
+            accumulator.add(element);
+            count++;
+        }
+        if (count > 0) {
+            result.add(accumulator);
+        }
+
+        return result;
+    }
+
+    /**
+     * Checks if a collection is empty or not. Empty collection mean either it is null or it has no elements in it.
+     * If collection contains a null element it means it is not empty.
+     *
+     * @param collection {@link Collection}
+     * @return true if collection is null or {@code isEmpty()}, false otherwise
+     * @param <E> Element
+     */
+    public static <E> boolean isEmpty(final Collection<E> collection) {
+        return collection == null || collection.isEmpty();
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/common/util/package-info.java b/libs/core/src/main/java/org/opensearch/core/common/util/package-info.java
new file mode 100644
index 0000000000000..57b1bfece1f90
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/common/util/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core util module */
+package org.opensearch.core.common.util;
diff --git a/server/src/main/java/org/opensearch/common/compress/Compressor.java b/libs/core/src/main/java/org/opensearch/core/compress/Compressor.java
similarity index 75%
rename from server/src/main/java/org/opensearch/common/compress/Compressor.java
rename to libs/core/src/main/java/org/opensearch/core/compress/Compressor.java
index b5116598ea4ce..27d5b5dfdfa15 100644
--- a/server/src/main/java/org/opensearch/common/compress/Compressor.java
+++ b/libs/core/src/main/java/org/opensearch/core/compress/Compressor.java
@@ -30,14 +30,29 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.compress;
+package org.opensearch.core.compress;
 
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+/**
+ * Compressor interface used for compressing {@link org.opensearch.core.xcontent.MediaType} and
+ * {@code org.opensearch.repositories.blobstore.BlobStoreRepository} implementations.
+ *
+ * This is not to be confused with {@link org.apache.lucene.codecs.compressing.Compressor} which is used
+ * for codec implementations such as {@code org.opensearch.index.codec.customcodecs.Lucene95CustomCodec}
+ * for compressing {@link org.apache.lucene.document.StoredField}s
+ *
+ * @opensearch.api - intended to be extended
+ * @opensearch.experimental - however, bwc is not guaranteed at this time
+ */
+@ExperimentalApi
+@PublicApi(since = "2.10.0")
 public interface Compressor {
 
     boolean isCompressed(BytesReference bytes);
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/CompressorRegistry.java b/libs/core/src/main/java/org/opensearch/core/compress/CompressorRegistry.java
new file mode 100644
index 0000000000000..9290254c30d8d
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/CompressorRegistry.java
@@ -0,0 +1,115 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.compress;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.spi.CompressorProvider;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Objects;
+import java.util.ServiceLoader;
+import java.util.stream.Collectors;
+
+/**
+ * A registry that wraps a static Map singleton which holds a mapping of unique String names (typically the
+ * compressor header as a string) to registerd {@link Compressor} implementations.
+ *
+ * This enables plugins, modules, extensions to register their own compression implementations through SPI
+ *
+ * @opensearch.experimental
+ * @opensearch.internal
+ */
+@InternalApi
+public final class CompressorRegistry {
+
+    // the backing registry map
+    private static final Map<String, Compressor> registeredCompressors = ServiceLoader.load(
+        CompressorProvider.class,
+        CompressorProvider.class.getClassLoader()
+    )
+        .stream()
+        .flatMap(p -> p.get().getCompressors().stream())
+        .collect(Collectors.toUnmodifiableMap(Map.Entry::getKey, Map.Entry::getValue));
+
+    // no instance:
+    private CompressorRegistry() {}
+
+    /**
+     * Returns the default compressor
+     */
+    public static Compressor defaultCompressor() {
+        return registeredCompressors.get("DEFLATE");
+    }
+
+    public static Compressor none() {
+        return registeredCompressors.get(NoneCompressor.NAME);
+    }
+
+    public static boolean isCompressed(BytesReference bytes) {
+        return compressor(bytes) != null;
+    }
+
+    @Nullable
+    public static Compressor compressor(final BytesReference bytes) {
+        for (Compressor compressor : registeredCompressors.values()) {
+            if (compressor.isCompressed(bytes) == true) {
+                // bytes should be either detected as compressed or as xcontent,
+                // if we have bytes that can be either detected as compressed or
+                // as a xcontent, we have a problem
+                assert MediaTypeRegistry.xContentType(bytes) == null;
+                return compressor;
+            }
+        }
+
+        if (MediaTypeRegistry.xContentType(bytes) == null) {
+            throw new NotXContentException("Compressor detection can only be called on some xcontent bytes or compressed xcontent bytes");
+        }
+
+        return null;
+    }
+
+    /** Decompress the provided {@link BytesReference}. */
+    public static BytesReference uncompress(BytesReference bytes) throws IOException {
+        Compressor compressor = compressor(bytes);
+        if (compressor == null) {
+            throw new NotCompressedException();
+        }
+        return compressor.uncompress(bytes);
+    }
+
+    /**
+     * Uncompress the provided data, data can be detected as compressed using {@link #isCompressed(BytesReference)}.
+     */
+    public static BytesReference uncompressIfNeeded(BytesReference bytes) throws IOException {
+        Compressor compressor = compressor(Objects.requireNonNull(bytes, "the BytesReference must not be null"));
+        return compressor == null ? bytes : compressor.uncompress(bytes);
+    }
+
+    /** Returns a registered compressor by its registered name */
+    public static Compressor getCompressor(final String name) {
+        if (registeredCompressors.containsKey(name)) {
+            return registeredCompressors.get(name);
+        }
+        throw new IllegalArgumentException("No registered compressor found by name [" + name + "]");
+    }
+
+    /**
+     * Returns the registered compressors as an Immutable collection
+     *
+     * note: used for testing
+     */
+    public static Map<String, Compressor> registeredCompressors() {
+        // no destructive danger as backing map is immutable
+        return registeredCompressors;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/NoneCompressor.java b/libs/core/src/main/java/org/opensearch/core/compress/NoneCompressor.java
new file mode 100644
index 0000000000000..6e607ed701633
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/NoneCompressor.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.compress;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.bytes.BytesReference;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * {@link Compressor} no compressor implementation.
+ *
+ * @opensearch.api - registered name requires BWC support
+ * @opensearch.experimental - class methods might change
+ */
+public class NoneCompressor implements Compressor {
+    /**
+     * The name to register the compressor by
+     *
+     * @opensearch.api - requires BWC support
+     */
+    @PublicApi(since = "2.10.0")
+    public static final String NAME = "NONE";
+
+    @Override
+    public boolean isCompressed(BytesReference bytes) {
+        return false;
+    }
+
+    @Override
+    public int headerLength() {
+        return 0;
+    }
+
+    @Override
+    public InputStream threadLocalInputStream(InputStream in) throws IOException {
+        return in;
+    }
+
+    @Override
+    public OutputStream threadLocalOutputStream(OutputStream out) throws IOException {
+        return out;
+    }
+
+    @Override
+    public BytesReference uncompress(BytesReference bytesReference) throws IOException {
+        return bytesReference;
+    }
+
+    @Override
+    public BytesReference compress(BytesReference bytesReference) throws IOException {
+        return bytesReference;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/common/compress/NotCompressedException.java b/libs/core/src/main/java/org/opensearch/core/compress/NotCompressedException.java
similarity index 83%
rename from server/src/main/java/org/opensearch/common/compress/NotCompressedException.java
rename to libs/core/src/main/java/org/opensearch/core/compress/NotCompressedException.java
index eedb3c0b9ac98..91d6bc57f1cd6 100644
--- a/server/src/main/java/org/opensearch/common/compress/NotCompressedException.java
+++ b/libs/core/src/main/java/org/opensearch/core/compress/NotCompressedException.java
@@ -30,11 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.compress;
+package org.opensearch.core.compress;
 
-/** Exception indicating that we were expecting something compressed, which
- *  was not compressed or corrupted so that the compression format could not
- *  be detected. */
+/**
+ * Exception indicating that we were expecting something compressed, which
+ * was not compressed or corrupted so that the compression format could not
+ * be detected.
+ *
+ *  @opensearch.internal
+ */
 public class NotCompressedException extends RuntimeException {
 
     public NotCompressedException() {
diff --git a/server/src/main/java/org/opensearch/common/compress/NotXContentException.java b/libs/core/src/main/java/org/opensearch/core/compress/NotXContentException.java
similarity index 84%
rename from server/src/main/java/org/opensearch/common/compress/NotXContentException.java
rename to libs/core/src/main/java/org/opensearch/core/compress/NotXContentException.java
index e06b6ee96ab72..99337d5a26025 100644
--- a/server/src/main/java/org/opensearch/common/compress/NotXContentException.java
+++ b/libs/core/src/main/java/org/opensearch/core/compress/NotXContentException.java
@@ -30,12 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.compress;
+package org.opensearch.core.compress;
 
-import org.opensearch.common.xcontent.XContent;
+import org.opensearch.core.xcontent.XContent;
 
-/** Exception indicating that we were expecting some {@link XContent} but could
- *  not detect its type. */
+/**
+ * Exception indicating that we were expecting some {@link XContent} but could
+ * not detect its type.
+ *
+ * @opensearch.internal
+ */
 public class NotXContentException extends RuntimeException {
 
     public NotXContentException(String message) {
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/package-info.java b/libs/core/src/main/java/org/opensearch/core/compress/package-info.java
new file mode 100644
index 0000000000000..c0365e45702bc
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/package-info.java
@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Concrete {@link org.opensearch.core.compress.Compressor} implementations provided by the core library
+ *
+ * See {@link org.opensearch.core.compress.NoneCompressor}
+ */
+package org.opensearch.core.compress;
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/spi/CompressorProvider.java b/libs/core/src/main/java/org/opensearch/core/compress/spi/CompressorProvider.java
new file mode 100644
index 0000000000000..019e282444d64
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/spi/CompressorProvider.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.compress.spi;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.compress.Compressor;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Service Provider Interface for plugins, modules, extensions providing custom
+ * compression algorithms
+ *
+ * see {@link Compressor} for implementing methods
+ * and {@link org.opensearch.core.compress.CompressorRegistry} for the registration of custom
+ * Compressors
+ *
+ * @opensearch.experimental
+ * @opensearch.api
+ */
+@ExperimentalApi
+@PublicApi(since = "2.10.0")
+public interface CompressorProvider {
+    /** Extensions that implement their own concrete {@link Compressor}s provide them through this interface method*/
+    List<Map.Entry<String, Compressor>> getCompressors();
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/spi/DefaultCompressorProvider.java b/libs/core/src/main/java/org/opensearch/core/compress/spi/DefaultCompressorProvider.java
new file mode 100644
index 0000000000000..3ca10b564ef68
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/spi/DefaultCompressorProvider.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.compress.spi;
+
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.NoneCompressor;
+
+import java.util.AbstractMap.SimpleEntry;
+import java.util.List;
+import java.util.Map.Entry;
+
+/**
+ * Default {@link Compressor} implementations provided by the
+ * opensearch core library
+ *
+ * @opensearch.internal
+ */
+public class DefaultCompressorProvider implements CompressorProvider {
+    /** Returns the default {@link Compressor}s provided by the core library */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @Override
+    public List<Entry<String, Compressor>> getCompressors() {
+        return List.of(new SimpleEntry(NoneCompressor.NAME, new NoneCompressor()));
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/compress/spi/package-info.java b/libs/core/src/main/java/org/opensearch/core/compress/spi/package-info.java
new file mode 100644
index 0000000000000..6e33cc8fb63d3
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/compress/spi/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The Service Provider Interface implementation for registering {@link org.opensearch.core.compress.Compressor}
+ * with the {@link org.opensearch.core.compress.CompressorRegistry}
+ *
+ * See {@link org.opensearch.core.compress.spi.DefaultCompressorProvider} as an example of registering the core
+ * {@link org.opensearch.core.compress.NoneCompressor}
+ */
+package org.opensearch.core.compress.spi;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchRejectedExecutionException.java b/libs/core/src/main/java/org/opensearch/core/concurrency/OpenSearchRejectedExecutionException.java
similarity index 95%
rename from server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchRejectedExecutionException.java
rename to libs/core/src/main/java/org/opensearch/core/concurrency/OpenSearchRejectedExecutionException.java
index aee5bc63d9dbc..2a1234eb66c4e 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchRejectedExecutionException.java
+++ b/libs/core/src/main/java/org/opensearch/core/concurrency/OpenSearchRejectedExecutionException.java
@@ -30,10 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.util.concurrent;
+package org.opensearch.core.concurrency;
 
 import java.util.concurrent.RejectedExecutionException;
 
+/**
+ * Thrown when an execution is rejected
+ *
+ * @opensearch.internal
+ */
 public class OpenSearchRejectedExecutionException extends RejectedExecutionException {
 
     private final boolean isExecutorShutdown;
diff --git a/libs/core/src/main/java/org/opensearch/core/concurrency/package-info.java b/libs/core/src/main/java/org/opensearch/core/concurrency/package-info.java
new file mode 100644
index 0000000000000..331066995ccd5
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/concurrency/package-info.java
@@ -0,0 +1,9 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+/** core concurrency package */
+package org.opensearch.core.concurrency;
diff --git a/libs/core/src/main/java/org/opensearch/core/index/Index.java b/libs/core/src/main/java/org/opensearch/core/index/Index.java
new file mode 100644
index 0000000000000..b5ee482bcd952
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/index/Index.java
@@ -0,0 +1,203 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.index;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * A value class representing the basic required properties of an OpenSearch index.
+ *
+ * (This class is immutable.)
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
+public class Index implements Writeable, ToXContentObject {
+
+    public static final Index[] EMPTY_ARRAY = new Index[0];
+    private static final String INDEX_UUID_KEY = "index_uuid";
+    private static final String INDEX_NAME_KEY = "index_name";
+    public static final String UNKNOWN_INDEX_NAME = "_unknown_";
+
+    private static final ObjectParser<Builder, Void> INDEX_PARSER = new ObjectParser<>("index", Builder::new);
+    static {
+        INDEX_PARSER.declareString(Builder::name, new ParseField(INDEX_NAME_KEY));
+        INDEX_PARSER.declareString(Builder::uuid, new ParseField(INDEX_UUID_KEY));
+    }
+
+    private final String name;
+    private final String uuid;
+
+    /**
+     * Creates a new Index instance with name and unique identifier
+     *
+     * @param name the name of the index
+     * @param uuid the unique identifier of the index
+     * @throws NullPointerException if either name or uuid are null
+     */
+    public Index(String name, String uuid) {
+        this.name = Objects.requireNonNull(name);
+        this.uuid = Objects.requireNonNull(uuid);
+    }
+
+    /**
+     * Creates a new Index instance from a {@link StreamInput}.
+     * Reads the name and unique identifier from the stream.
+     *
+     * @param in the stream to read from
+     * @throws IOException if an error occurs while reading from the stream
+     * @see #writeTo(StreamOutput)
+     */
+    public Index(StreamInput in) throws IOException {
+        this.name = in.readString();
+        this.uuid = in.readString();
+    }
+
+    /**
+     * Gets the name of the index.
+     *
+     * @return the name of the index.
+     */
+    public String getName() {
+        return this.name;
+    }
+
+    /**
+     * Gets the unique identifier of the index.
+     *
+     * @return the unique identifier of the index. "_na_" if {@link Strings#UNKNOWN_UUID_VALUE}.
+     */
+    public String getUUID() {
+        return uuid;
+    }
+
+    /**
+     * Returns either the name and unique identifier of the index
+     * or only the name if the uuid is {@link Strings#UNKNOWN_UUID_VALUE}.
+     *
+     * If we have a uuid we put it in the toString so it'll show up in logs
+     * which is useful as more and more things use the uuid rather
+     * than the name as the lookup key for the index.
+     *
+     * @return {@code "[name/uuid]"} or {@code "[name]"}
+     */
+    @Override
+    public String toString() {
+        if (Strings.UNKNOWN_UUID_VALUE.equals(uuid)) {
+            return "[" + name + "]";
+        }
+        return "[" + name + "/" + uuid + "]";
+    }
+
+    /**
+     * Checks if this index is the same as another index by comparing the name and unique identifier.
+     * If both uuid are {@link Strings#UNKNOWN_UUID_VALUE} then only the name is compared.
+     *
+     * @param o the index to compare to
+     * @return true if the name and unique identifier are the same, false otherwise.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Index index1 = (Index) o;
+        return uuid.equals(index1.uuid) && name.equals(index1.name); // allow for _na_ uuid
+    }
+
+    @Override
+    public int hashCode() {
+        int result = name.hashCode();
+        result = 31 * result + uuid.hashCode();
+        return result;
+    }
+
+    /** Writes the name and unique identifier to the {@link StreamOutput}
+     *
+     * @param out The stream to write to
+     */
+    @Override
+    public void writeTo(final StreamOutput out) throws IOException {
+        out.writeString(name);
+        out.writeString(uuid);
+    }
+
+    @Override
+    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
+        builder.startObject();
+        builder.field(INDEX_NAME_KEY, name);
+        builder.field(INDEX_UUID_KEY, uuid);
+        return builder.endObject();
+    }
+
+    public static Index fromXContent(final XContentParser parser) throws IOException {
+        return INDEX_PARSER.parse(parser, null).build();
+    }
+
+    /**
+     * Builder for Index objects.  Used by ObjectParser instances only.
+     *
+     * @opensearch.internal
+     */
+    private static final class Builder {
+        private String name;
+        private String uuid;
+
+        public void name(final String name) {
+            this.name = name;
+        }
+
+        public void uuid(final String uuid) {
+            this.uuid = uuid;
+        }
+
+        public Index build() {
+            return new Index(name, uuid);
+        }
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/index/package-info.java b/libs/core/src/main/java/org/opensearch/core/index/package-info.java
new file mode 100644
index 0000000000000..31ecb88948c9d
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/index/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core index module */
+package org.opensearch.core.index;
diff --git a/libs/core/src/main/java/org/opensearch/core/index/shard/ShardId.java b/libs/core/src/main/java/org/opensearch/core/index/shard/ShardId.java
new file mode 100644
index 0000000000000..984434190b486
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/index/shard/ShardId.java
@@ -0,0 +1,212 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.index.shard;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Allows for shard level components to be injected with the shard id.
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
+public class ShardId implements Comparable<ShardId>, ToXContentFragment, Writeable {
+
+    private final Index index;
+    private final int shardId;
+    private final int hashCode;
+
+    /**
+     * Constructs a new shard id.
+     * @param index the index name
+     * @param shardId the shard id
+     */
+    public ShardId(Index index, int shardId) {
+        this.index = index;
+        this.shardId = shardId;
+        this.hashCode = computeHashCode();
+    }
+
+    /**
+     * Constructs a new shard id with the given index name, index unique identifier, and shard id.
+     * @param index the index name
+     * @param indexUUID  the index unique identifier
+     * @param shardId the shard id
+     */
+    public ShardId(String index, String indexUUID, int shardId) {
+        this(new Index(index, indexUUID), shardId);
+    }
+
+    /**
+     * Constructs a new shardId from a stream.
+     * @param in the stream to read from
+     * @throws IOException if an error occurs while reading from the stream
+     * @see #writeTo(StreamOutput)
+     */
+    public ShardId(StreamInput in) throws IOException {
+        index = new Index(in);
+        shardId = in.readVInt();
+        hashCode = computeHashCode();
+    }
+
+    /**
+     * Writes this shard id to a stream.
+     * @param out the stream to write to
+     * @throws IOException if an error occurs while writing to the stream
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        index.writeTo(out);
+        out.writeVInt(shardId);
+    }
+
+    /**
+     * Returns the index of this shard id.
+     * @return the index of this shard id
+     */
+    public Index getIndex() {
+        return index;
+    }
+
+    /**
+     * Returns the name of the index of this shard id.
+     * @return the name of the index of this shard id
+     */
+    public String getIndexName() {
+        return index.getName();
+    }
+
+    /**
+     *  Return the shardId of this shard id.
+     * @return the shardId of this shard id
+     * @see #getId()
+     */
+    public int id() {
+        return this.shardId;
+    }
+
+    /**
+     * Returns the shard id of this shard id.
+     * @return the shard id of this shard id
+     */
+    public int getId() {
+        return id();
+    }
+
+    /**
+     * Returns a string representation of this shard id.
+     * @return "[indexName][shardId]"
+     */
+    @Override
+    public String toString() {
+        return "[" + index.getName() + "][" + shardId + "]";
+    }
+
+    /**
+     * Parse the string representation of this shardId back to an object.
+     *
+     * We lose index uuid information here, but since we use toString in
+     * rest responses, this is the best we can do to reconstruct the object
+     * on the client side.
+     *
+     * @param shardIdString the string representation of the shard id
+     *                      (Expect a string of format "[indexName][shardId]" (square brackets included))
+     */
+    public static ShardId fromString(String shardIdString) {
+        int splitPosition = shardIdString.indexOf("][");
+        if (splitPosition <= 0 || shardIdString.charAt(0) != '[' || shardIdString.charAt(shardIdString.length() - 1) != ']') {
+            throw new IllegalArgumentException("Unexpected shardId string format, expected [indexName][shardId] but got " + shardIdString);
+        }
+        String indexName = shardIdString.substring(1, splitPosition);
+        int shardId = Integer.parseInt(shardIdString.substring(splitPosition + 2, shardIdString.length() - 1));
+        return new ShardId(new Index(indexName, Strings.UNKNOWN_UUID_VALUE), shardId);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ShardId shardId1 = (ShardId) o;
+        return shardId == shardId1.shardId && index.equals(shardId1.index);
+    }
+
+    /** Returns the hash code of this shard id.
+     *
+     * @return the hash code of this shard id
+     */
+    @Override
+    public int hashCode() {
+        return hashCode;
+    }
+
+    /** Computes the hash code of this shard id.
+     *
+     * @return the hash code of this shard id.
+     */
+    private int computeHashCode() {
+        int result = index != null ? index.hashCode() : 0;
+        result = 31 * result + shardId;
+        return result;
+    }
+
+    /**
+     * Compares this ShardId with the specified ShardId.
+     * @param o the ShardId to be compared.
+     * @return a negative integer, zero, or a positive integer if this ShardId is less than, equal to, or greater than the specified ShardId
+     */
+    @Override
+    public int compareTo(ShardId o) {
+        if (o.getId() == shardId) {
+            int compare = index.getName().compareTo(o.getIndex().getName());
+            if (compare != 0) {
+                return compare;
+            }
+            return index.getUUID().compareTo(o.getIndex().getUUID());
+        }
+        return Integer.compare(shardId, o.getId());
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/index/shard/package-info.java b/libs/core/src/main/java/org/opensearch/core/index/shard/package-info.java
new file mode 100644
index 0000000000000..267d558a5092c
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/index/shard/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core index/shard module */
+package org.opensearch.core.index.shard;
diff --git a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotException.java b/libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotException.java
similarity index 90%
rename from server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotException.java
rename to libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotException.java
index db7550c964299..24e91ca949551 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotException.java
+++ b/libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotException.java
@@ -30,16 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.index.snapshots;
+package org.opensearch.core.index.snapshots;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Generic shard snapshot exception
+ *
+ * @opensearch.internal
  */
 public class IndexShardSnapshotException extends OpenSearchException {
     public IndexShardSnapshotException(ShardId shardId, String msg) {
diff --git a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotFailedException.java b/libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotFailedException.java
similarity index 90%
rename from server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotFailedException.java
rename to libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotFailedException.java
index 236cd668f443d..32d1a49c46f9e 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotFailedException.java
+++ b/libs/core/src/main/java/org/opensearch/core/index/snapshots/IndexShardSnapshotFailedException.java
@@ -30,15 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.index.snapshots;
+package org.opensearch.core.index.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Thrown when snapshot process is failed on a shard level
+ *
+ * @opensearch.internal
  */
 public class IndexShardSnapshotFailedException extends IndexShardSnapshotException {
     public IndexShardSnapshotFailedException(ShardId shardId, String msg) {
diff --git a/libs/core/src/main/java/org/opensearch/core/index/snapshots/package-info.java b/libs/core/src/main/java/org/opensearch/core/index/snapshots/package-info.java
new file mode 100644
index 0000000000000..b3bb62e40b7d0
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/index/snapshots/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core snapshots module */
+package org.opensearch.core.index.snapshots;
diff --git a/libs/core/src/main/java/org/opensearch/core/indices/breaker/AllCircuitBreakerStats.java b/libs/core/src/main/java/org/opensearch/core/indices/breaker/AllCircuitBreakerStats.java
new file mode 100644
index 0000000000000..3ce8b4953b9d6
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/indices/breaker/AllCircuitBreakerStats.java
@@ -0,0 +1,124 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.indices.breaker;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Stats class encapsulating all of the different circuit breaker stats
+ *
+ * @opensearch.internal
+ */
+public class AllCircuitBreakerStats implements Writeable, ToXContentFragment {
+
+    /** An array of all the circuit breaker stats */
+    private final CircuitBreakerStats[] allStats;
+
+    /**
+     * Constructs the instance
+     *
+     * @param allStats an array of all the circuit breaker stats
+     */
+    public AllCircuitBreakerStats(CircuitBreakerStats[] allStats) {
+        this.allStats = allStats;
+    }
+
+    /**
+     * Constructs the new instance from {@link StreamInput}
+     * @param in the  {@link StreamInput} to read from
+     * @throws IOException If an error occurs while reading from the StreamInput
+     * @see #writeTo(StreamOutput)
+     */
+    public AllCircuitBreakerStats(StreamInput in) throws IOException {
+        allStats = in.readArray(CircuitBreakerStats::new, CircuitBreakerStats[]::new);
+    }
+
+    /**
+     * Writes this instance into a {@link StreamOutput}
+     * @param out the {@link StreamOutput} to write to
+     * @throws IOException if an error occurs while writing to the StreamOutput
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeArray(allStats);
+    }
+
+    /**
+     * Returns inner stats instances for all circuit breakers
+     * @return inner stats instances for all circuit breakers
+     */
+    public CircuitBreakerStats[] getAllStats() {
+        return this.allStats;
+    }
+
+    /**
+     * Returns the stats for a specific circuit breaker
+     * @param name the name of the circuit breaker
+     * @return  the {@link CircuitBreakerStats} for the circuit breaker, null if the circuit breaker with such name does not exist
+     */
+    public CircuitBreakerStats getStats(String name) {
+        for (CircuitBreakerStats stats : allStats) {
+            if (stats.getName().equals(name)) {
+                return stats;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(Fields.BREAKERS);
+        for (CircuitBreakerStats stats : allStats) {
+            if (stats != null) {
+                stats.toXContent(builder, params);
+            }
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
+    static final class Fields {
+        static final String BREAKERS = "breakers";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerService.java b/libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerService.java
similarity index 91%
rename from server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerService.java
rename to libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerService.java
index fd7ce00fde798..ee9c94f432a36 100644
--- a/server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerService.java
+++ b/libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerService.java
@@ -30,16 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.indices.breaker;
+package org.opensearch.core.indices.breaker;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.core.common.breaker.CircuitBreaker;
 
 /**
  * Interface for Circuit Breaker services, which provide breakers to classes
  * that load field data.
+ *
+ * @opensearch.internal
  */
 public abstract class CircuitBreakerService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(CircuitBreakerService.class);
diff --git a/libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerStats.java b/libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerStats.java
new file mode 100644
index 0000000000000..9207d3ea77227
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/indices/breaker/CircuitBreakerStats.java
@@ -0,0 +1,202 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.indices.breaker;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Locale;
+
+/**
+ * Class encapsulating stats about the {@link org.opensearch.core.common.breaker.CircuitBreaker}
+ *
+ * @opensearch.internal
+ */
+public class CircuitBreakerStats implements Writeable, ToXContentObject {
+
+    /** The name of the circuit breaker */
+    private final String name;
+    /** The limit size in byte of the circuit breaker. Field : "limit_size_in_bytes" */
+    private final long limit;
+    /** The estimated size in byte of the breaker. Field : "estimated_size_in_bytes" */
+    private final long estimated;
+    /** The number of times the breaker has been tripped. Field : "tripped" */
+    private final long trippedCount;
+    /** The overhead of the breaker. Field : "overhead" */
+    private final double overhead;
+
+    /**
+     * Constructs new instance
+     *
+     * @param name The name of the circuit breaker
+     * @param limit The limit size in byte of the circuit breaker
+     * @param estimated The estimated size in byte of the breaker
+     * @param overhead The overhead of the breaker
+     * @param trippedCount The number of times the breaker has been tripped
+     * @see org.opensearch.core.common.breaker.CircuitBreaker
+     */
+    public CircuitBreakerStats(String name, long limit, long estimated, double overhead, long trippedCount) {
+        this.name = name;
+        this.limit = limit;
+        this.estimated = estimated;
+        this.trippedCount = trippedCount;
+        this.overhead = overhead;
+    }
+
+    /**
+     * Constructs new instance from the {@link StreamInput}
+     *
+     * @param in The StreamInput
+     * @throws IOException if an error occurs while reading from the StreamInput
+     * @see org.opensearch.core.common.breaker.CircuitBreaker
+     * @see #writeTo(StreamOutput)
+     */
+    public CircuitBreakerStats(StreamInput in) throws IOException {
+        this.limit = in.readLong();
+        this.estimated = in.readLong();
+        this.overhead = in.readDouble();
+        this.trippedCount = in.readLong();
+        this.name = in.readString();
+    }
+
+    /**
+     * Writes this instance into a {@link StreamOutput}
+     *
+     * @param out The StreamOutput
+     * @throws IOException if an error occurs while writing to the StreamOutput
+     * @see #CircuitBreakerStats(StreamInput)
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeLong(limit);
+        out.writeLong(estimated);
+        out.writeDouble(overhead);
+        out.writeLong(trippedCount);
+        out.writeString(name);
+    }
+
+    /**
+     * Returns the name of the circuit breaker
+     * @return The name of the circuit breaker
+     */
+    public String getName() {
+        return this.name;
+    }
+
+    /**
+     * Returns the limit size in byte of the circuit breaker
+     * @return The limit size in byte of the circuit breaker
+     */
+    public long getLimit() {
+        return this.limit;
+    }
+
+    /**
+     * Returns the estimated size in byte of the breaker
+     * @return The estimated size in byte of the breaker
+     */
+    public long getEstimated() {
+        return this.estimated;
+    }
+
+    /**
+     * Returns the number of times the breaker has been tripped
+     * @return The number of times the breaker has been tripped
+     */
+    public long getTrippedCount() {
+        return this.trippedCount;
+    }
+
+    /**
+     * Returns the overhead of the breaker
+     * @return The overhead of the breaker
+     */
+    public double getOverhead() {
+        return this.overhead;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(name.toLowerCase(Locale.ROOT));
+        builder.field(Fields.LIMIT, limit);
+        builder.field(Fields.LIMIT_HUMAN, new ByteSizeValue(limit));
+        builder.field(Fields.ESTIMATED, estimated);
+        builder.field(Fields.ESTIMATED_HUMAN, new ByteSizeValue(estimated));
+        builder.field(Fields.OVERHEAD, overhead);
+        builder.field(Fields.TRIPPED_COUNT, trippedCount);
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * Returns a String representation of this CircuitBreakerStats
+     * @return "[name,limit=limit/limit_human,estimated=estimated/estimated_human,overhead=overhead,tripped=trippedCount]"
+     */
+    @Override
+    public String toString() {
+        return "["
+            + this.name
+            + ",limit="
+            + this.limit
+            + "/"
+            + new ByteSizeValue(this.limit)
+            + ",estimated="
+            + this.estimated
+            + "/"
+            + new ByteSizeValue(this.estimated)
+            + ",overhead="
+            + this.overhead
+            + ",tripped="
+            + this.trippedCount
+            + "]";
+    }
+
+    /**
+     * Fields used for statistics
+     *
+     * @opensearch.internal
+     */
+    static final class Fields {
+        static final String LIMIT = "limit_size_in_bytes";
+        static final String LIMIT_HUMAN = "limit_size";
+        static final String ESTIMATED = "estimated_size_in_bytes";
+        static final String ESTIMATED_HUMAN = "estimated_size";
+        static final String OVERHEAD = "overhead";
+        static final String TRIPPED_COUNT = "tripped";
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/indices/breaker/NoneCircuitBreakerService.java b/libs/core/src/main/java/org/opensearch/core/indices/breaker/NoneCircuitBreakerService.java
new file mode 100644
index 0000000000000..49c5a393328b9
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/indices/breaker/NoneCircuitBreakerService.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.indices.breaker;
+
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+
+/**
+ * Class that returns a breaker that use the NoopCircuitBreaker and never breaks
+ *
+ * @see org.opensearch.core.common.breaker.NoopCircuitBreaker
+ * @opensearch.internal
+ */
+public class NoneCircuitBreakerService extends CircuitBreakerService {
+
+    private final CircuitBreaker breaker = new NoopCircuitBreaker(CircuitBreaker.FIELDDATA);
+
+    public NoneCircuitBreakerService() {
+        super();
+    }
+
+    /**
+     * Returns a breaker that use the NoopCircuitBreaker and never breaks
+     *
+     * @param name name of the breaker (ignored)
+     * @return a NoopCircuitBreaker
+     */
+    @Override
+    public CircuitBreaker getBreaker(String name) {
+        return breaker;
+    }
+
+    @Override
+    public AllCircuitBreakerStats stats() {
+        return new AllCircuitBreakerStats(new CircuitBreakerStats[] { stats(CircuitBreaker.FIELDDATA) });
+    }
+
+    /**
+     * Always returns the same stats, a NoopCircuitBreaker never breaks and all operations are noops.
+     *
+     * @param name name of the breaker (ignored)
+     * @return always "fielddata", limit: -1, estimated: -1, overhead: 0, trippedCount: 0
+     */
+    @Override
+    public CircuitBreakerStats stats(String name) {
+        return new CircuitBreakerStats(CircuitBreaker.FIELDDATA, -1, -1, 0, 0);
+    }
+
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/indices/breaker/package-info.java b/libs/core/src/main/java/org/opensearch/core/indices/breaker/package-info.java
new file mode 100644
index 0000000000000..a98f9ab1d9f1e
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/indices/breaker/package-info.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Top Level core circuit breaker implementation
+ *
+ * @opensearch.internal
+ * @opensearch.experimental
+ */
+package org.opensearch.core.indices.breaker;
diff --git a/libs/core/src/main/java/org/opensearch/core/indices/package-info.java b/libs/core/src/main/java/org/opensearch/core/indices/package-info.java
new file mode 100644
index 0000000000000..c80edf3d2f01a
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/indices/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Top Level Package for implementations used across indexes
+ */
+package org.opensearch.core.indices;
diff --git a/libs/core/src/main/java/org/opensearch/core/internal/io/Streams.java b/libs/core/src/main/java/org/opensearch/core/internal/io/Streams.java
deleted file mode 100644
index 1938e1bbf4dff..0000000000000
--- a/libs/core/src/main/java/org/opensearch/core/internal/io/Streams.java
+++ /dev/null
@@ -1,106 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.core.internal.io;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-
-/**
- * Simple utility methods for file and stream copying.
- * All copy methods use a block size of 4096 bytes,
- * and close all affected streams when done.
- * <p>
- * Mainly for use within the framework,
- * but also useful for application code.
- */
-public class Streams {
-
-    private static final ThreadLocal<byte[]> buffer = ThreadLocal.withInitial(() -> new byte[8 * 1024]);
-
-    private Streams() {
-
-    }
-
-    /**
-     * Copy the contents of the given InputStream to the given OutputStream. Optionally, closes both streams when done.
-     *
-     * @param in     the stream to copy from
-     * @param out    the stream to copy to
-     * @param close  whether to close both streams after copying
-     * @param buffer buffer to use for copying
-     * @return the number of bytes copied
-     * @throws IOException in case of I/O errors
-     */
-    public static long copy(final InputStream in, final OutputStream out, byte[] buffer, boolean close) throws IOException {
-        Exception err = null;
-        try {
-            long byteCount = 0;
-            int bytesRead;
-            while ((bytesRead = in.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesRead);
-                byteCount += bytesRead;
-            }
-            out.flush();
-            return byteCount;
-        } catch (IOException | RuntimeException e) {
-            err = e;
-            throw e;
-        } finally {
-            if (close) {
-                IOUtils.close(err, in, out);
-            }
-        }
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out, boolean close) throws IOException {
-        return copy(in, out, buffer.get(), close);
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out, byte[] buffer) throws IOException {
-        return copy(in, out, buffer, true);
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out) throws IOException {
-        return copy(in, out, buffer.get(), true);
-    }
-}
diff --git a/libs/core/src/main/java/org/opensearch/core/package-info.java b/libs/core/src/main/java/org/opensearch/core/package-info.java
new file mode 100644
index 0000000000000..b64298ad0788b
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Core Library Classes */
+package org.opensearch.core;
diff --git a/server/src/main/java/org/opensearch/rest/RestStatus.java b/libs/core/src/main/java/org/opensearch/core/rest/RestStatus.java
similarity index 97%
rename from server/src/main/java/org/opensearch/rest/RestStatus.java
rename to libs/core/src/main/java/org/opensearch/core/rest/RestStatus.java
index 5f50559ef0f51..8441ce8b1b622 100644
--- a/server/src/main/java/org/opensearch/rest/RestStatus.java
+++ b/libs/core/src/main/java/org/opensearch/core/rest/RestStatus.java
@@ -30,11 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.rest;
+package org.opensearch.core.rest;
 
-import org.opensearch.action.ShardOperationFailedException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -42,6 +43,12 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * OpenSearch REST status
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public enum RestStatus {
     /**
      * The client SHOULD continue with its request. This interim response is used to inform the client that the
@@ -426,6 +433,12 @@ public enum RestStatus {
      * next-hop server.
      */
     EXPECTATION_FAILED(417),
+    /**
+     * The request was directed at a server that is not able to produce a response. This can be sent by a server
+     * that is not configured to produce responses for the combination of scheme and authority that are included
+     * in the request URI.
+     */
+    MISDIRECTED_REQUEST(421),
     /**
      * The 422 (Unprocessable Entity) status code means the server understands the content type of the request
      * entity (hence a 415(Unsupported Media Type) status code is inappropriate), and the syntax of the request
@@ -514,6 +527,15 @@ public int getStatus() {
         return status;
     }
 
+    /**
+     * Get category class of a rest status code.
+     *
+     * @return Integer representing class category of the concrete rest status code
+     */
+    public int getStatusFamilyCode() {
+        return status / 100;
+    }
+
     public static RestStatus readFrom(StreamInput in) throws IOException {
         return RestStatus.valueOf(in.readString());
     }
diff --git a/libs/core/src/main/java/org/opensearch/core/rest/package-info.java b/libs/core/src/main/java/org/opensearch/core/rest/package-info.java
new file mode 100644
index 0000000000000..8c99d38e5f003
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/rest/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for core REST module */
+package org.opensearch.core.rest;
diff --git a/server/src/main/java/org/opensearch/node/ReportingService.java b/libs/core/src/main/java/org/opensearch/core/service/ReportingService.java
similarity index 81%
rename from server/src/main/java/org/opensearch/node/ReportingService.java
rename to libs/core/src/main/java/org/opensearch/core/service/ReportingService.java
index 3d81a0f8976a5..3c88169f1e3b0 100644
--- a/server/src/main/java/org/opensearch/node/ReportingService.java
+++ b/libs/core/src/main/java/org/opensearch/core/service/ReportingService.java
@@ -30,14 +30,24 @@
  * GitHub history for details.
  */
 
-package org.opensearch.node;
+package org.opensearch.core.service;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
 
+/**
+ * Node reporting service
+ *
+ * @opensearch.internal
+ */
 public interface ReportingService<I extends ReportingService.Info> {
     I info();
 
+    /**
+     * Information interface.
+     *
+     * @opensearch.internal
+     */
     interface Info extends Writeable, ToXContent {
 
     }
diff --git a/libs/core/src/main/java/org/opensearch/core/service/package-info.java b/libs/core/src/main/java/org/opensearch/core/service/package-info.java
new file mode 100644
index 0000000000000..d427c6e5934c9
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/service/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch Core Service Interfaces */
+package org.opensearch.core.service;
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancelledException.java b/libs/core/src/main/java/org/opensearch/core/tasks/TaskCancelledException.java
similarity index 92%
rename from server/src/main/java/org/opensearch/tasks/TaskCancelledException.java
rename to libs/core/src/main/java/org/opensearch/core/tasks/TaskCancelledException.java
index f9863a10639e0..6bdc1e42f351a 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskCancelledException.java
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/TaskCancelledException.java
@@ -29,15 +29,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.tasks;
+package org.opensearch.core.tasks;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A generic exception that can be thrown by a task when it's cancelled by the task manager API
+ *
+ * @opensearch.internal
  */
 public class TaskCancelledException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/tasks/TaskId.java b/libs/core/src/main/java/org/opensearch/core/tasks/TaskId.java
similarity index 91%
rename from server/src/main/java/org/opensearch/tasks/TaskId.java
rename to libs/core/src/main/java/org/opensearch/core/tasks/TaskId.java
index e98df346b7041..d34d4acf00e6e 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskId.java
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/TaskId.java
@@ -30,21 +30,25 @@
  * GitHub history for details.
  */
 
-package org.opensearch.tasks;
+package org.opensearch.core.tasks;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * Task id that consists of node id and id of the task on the node
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class TaskId implements Writeable {
 
     public static final TaskId EMPTY_TASK_ID = new TaskId();
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/package-info.java b/libs/core/src/main/java/org/opensearch/core/tasks/package-info.java
new file mode 100644
index 0000000000000..e421816c6b541
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core Tasks Foundation classes used across the opensearch code base */
+package org.opensearch.core.tasks;
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStats.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStats.java
new file mode 100644
index 0000000000000..d65f75581dd1b
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStats.java
@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+/**
+ *  Different resource stats are defined.
+ *
+ *  @opensearch.internal
+ */
+public enum ResourceStats {
+    CPU("cpu_time_in_nanos"),
+    MEMORY("memory_in_bytes");
+
+    private final String statsName;
+
+    ResourceStats(String statsName) {
+        this.statsName = statsName;
+    }
+
+    @Override
+    public String toString() {
+        return statsName;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStatsType.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStatsType.java
new file mode 100644
index 0000000000000..fce8cc65e9bc5
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceStatsType.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+/**
+ * Defines the different types of resource stats.
+ *
+ * @opensearch.internal
+ */
+public enum ResourceStatsType {
+    // resource stats of the worker thread reported directly from runnable.
+    WORKER_STATS("worker_stats", false);
+
+    private final String statsType;
+    private final boolean onlyForAnalysis;
+
+    ResourceStatsType(String statsType, boolean onlyForAnalysis) {
+        this.statsType = statsType;
+        this.onlyForAnalysis = onlyForAnalysis;
+    }
+
+    public boolean isOnlyForAnalysis() {
+        return onlyForAnalysis;
+    }
+
+    @Override
+    public String toString() {
+        return statsType;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageInfo.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageInfo.java
new file mode 100644
index 0000000000000..2cbc3d4b2f5c3
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageInfo.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Thread resource usage information for particular resource stats type.
+ * <p>
+ * It captures the resource usage information like memory, CPU about a particular execution of thread
+ * for a specific stats type.
+ *
+ * @opensearch.internal
+ */
+public class ResourceUsageInfo {
+    private static final Logger logger = LogManager.getLogger(ResourceUsageInfo.class);
+    private final EnumMap<ResourceStats, ResourceStatsInfo> statsInfo = new EnumMap<>(ResourceStats.class);
+
+    public ResourceUsageInfo(ResourceUsageMetric... resourceUsageMetrics) {
+        for (ResourceUsageMetric resourceUsageMetric : resourceUsageMetrics) {
+            this.statsInfo.put(resourceUsageMetric.getStats(), new ResourceStatsInfo(resourceUsageMetric.getValue()));
+        }
+    }
+
+    public void recordResourceUsageMetrics(ResourceUsageMetric... resourceUsageMetrics) {
+        for (ResourceUsageMetric resourceUsageMetric : resourceUsageMetrics) {
+            final ResourceStatsInfo resourceStatsInfo = statsInfo.get(resourceUsageMetric.getStats());
+            if (resourceStatsInfo != null) {
+                updateResourceUsageInfo(resourceStatsInfo, resourceUsageMetric);
+            } else {
+                throw new IllegalStateException(
+                    "cannot update ["
+                        + resourceUsageMetric.getStats().toString()
+                        + "] entry as its not present current_stats_info:"
+                        + statsInfo
+                );
+            }
+        }
+    }
+
+    private void updateResourceUsageInfo(ResourceStatsInfo resourceStatsInfo, ResourceUsageMetric resourceUsageMetric) {
+        long currentEndValue;
+        long newEndValue;
+        do {
+            currentEndValue = resourceStatsInfo.endValue.get();
+            newEndValue = resourceUsageMetric.getValue();
+            if (currentEndValue > newEndValue) {
+                logger.debug(
+                    "dropping resource usage update as the new value is lower than current value ["
+                        + "resource_stats=[{}], "
+                        + "current_end_value={}, "
+                        + "new_end_value={}]",
+                    resourceUsageMetric.getStats(),
+                    currentEndValue,
+                    newEndValue
+                );
+                return;
+            }
+        } while (!resourceStatsInfo.endValue.compareAndSet(currentEndValue, newEndValue));
+        logger.debug(
+            "updated resource usage info [resource_stats=[{}], " + "old_end_value={}, new_end_value={}]",
+            resourceUsageMetric.getStats(),
+            currentEndValue,
+            newEndValue
+        );
+    }
+
+    public Map<ResourceStats, ResourceStatsInfo> getStatsInfo() {
+        return Collections.unmodifiableMap(statsInfo);
+    }
+
+    @Override
+    public String toString() {
+        return statsInfo.toString();
+    }
+
+    /**
+     *  Defines resource stats information.
+     */
+    public static class ResourceStatsInfo {
+        private final long startValue;
+        private final AtomicLong endValue;
+
+        private ResourceStatsInfo(long startValue) {
+            this.startValue = startValue;
+            this.endValue = new AtomicLong(startValue);
+        }
+
+        public long getTotalValue() {
+            return endValue.get() - startValue;
+        }
+
+        @Override
+        public String toString() {
+            return String.valueOf(getTotalValue());
+        }
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageMetric.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageMetric.java
new file mode 100644
index 0000000000000..262dbe20dabda
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ResourceUsageMetric.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+/**
+ * Information about resource usage
+ *
+ * @opensearch.internal
+ */
+public class ResourceUsageMetric {
+    private final ResourceStats stats;
+    private final long value;
+
+    public ResourceUsageMetric(ResourceStats stats, long value) {
+        this.stats = stats;
+        this.value = value;
+    }
+
+    public ResourceStats getStats() {
+        return stats;
+    }
+
+    public long getValue() {
+        return value;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceStats.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceStats.java
new file mode 100644
index 0000000000000..d0d26550a4742
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceStats.java
@@ -0,0 +1,137 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+import org.opensearch.Version;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Resource information about a currently running task.
+ * <p>
+ * Writeable TaskResourceStats objects are used to represent resource
+ * snapshot information about currently running task.
+ *
+ * @opensearch.internal
+ */
+public class TaskResourceStats implements Writeable, ToXContentFragment {
+    private final Map<String, TaskResourceUsage> resourceUsage;
+    private final TaskThreadUsage threadUsage;
+
+    public static final String THREAD_INFO = "thread_info";
+
+    public TaskResourceStats(Map<String, TaskResourceUsage> resourceUsage, TaskThreadUsage threadUsage) {
+        this.resourceUsage = Objects.requireNonNull(resourceUsage, "resource usage is required");
+        this.threadUsage = Objects.requireNonNull(threadUsage, "thread usage is required");
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public TaskResourceStats(StreamInput in) throws IOException {
+        resourceUsage = in.readMap(StreamInput::readString, TaskResourceUsage::readFromStream);
+        if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+            threadUsage = TaskThreadUsage.readFromStream(in);
+        } else {
+            // Initialize TaskThreadUsage in case it is not found in mixed cluster case
+            threadUsage = new TaskThreadUsage(0, 0);
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeMap(resourceUsage, StreamOutput::writeString, (stream, stats) -> stats.writeTo(stream));
+        if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+            threadUsage.writeTo(out);
+        }
+    }
+
+    public Map<String, TaskResourceUsage> getResourceUsageInfo() {
+        return resourceUsage;
+    }
+
+    public TaskThreadUsage getThreadUsage() {
+        return threadUsage;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        for (Map.Entry<String, TaskResourceUsage> resourceUsageEntry : resourceUsage.entrySet()) {
+            builder.startObject(resourceUsageEntry.getKey());
+            if (resourceUsageEntry.getValue() != null) {
+                resourceUsageEntry.getValue().toXContent(builder, params);
+            }
+            builder.endObject();
+        }
+        builder.startObject(THREAD_INFO);
+        threadUsage.toXContent(builder, params);
+        builder.endObject();
+        return builder;
+    }
+
+    public static TaskResourceStats fromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token = parser.currentToken();
+        if (token == null) {
+            token = parser.nextToken();
+        }
+        if (token == XContentParser.Token.START_OBJECT) {
+            token = parser.nextToken();
+        }
+        final Map<String, TaskResourceUsage> resourceStats = new HashMap<>();
+        // Initialize TaskThreadUsage in case it is not found in mixed cluster case
+        TaskThreadUsage threadUsage = new TaskThreadUsage(0, 0);
+        if (token == XContentParser.Token.FIELD_NAME) {
+            assert parser.currentToken() == XContentParser.Token.FIELD_NAME : "Expected field name but saw [" + parser.currentToken() + "]";
+            do {
+                // Must point to field name
+                String fieldName = parser.currentName();
+                // And then the value
+
+                if (fieldName.equals(THREAD_INFO)) {
+                    threadUsage = TaskThreadUsage.fromXContent(parser);
+                } else {
+                    TaskResourceUsage value = TaskResourceUsage.fromXContent(parser);
+                    resourceStats.put(fieldName, value);
+                }
+            } while (parser.nextToken() == XContentParser.Token.FIELD_NAME);
+        }
+        return new TaskResourceStats(resourceStats, threadUsage);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
+    }
+
+    // Implements equals and hashcode for testing
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null || obj.getClass() != TaskResourceStats.class) {
+            return false;
+        }
+        TaskResourceStats other = (TaskResourceStats) obj;
+        return Objects.equals(resourceUsage, other.resourceUsage);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(resourceUsage);
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceUsage.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceUsage.java
new file mode 100644
index 0000000000000..7d6cadbef23d7
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskResourceUsage.java
@@ -0,0 +1,108 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * Task resource usage information
+ * <p>
+ * Writeable TaskResourceUsage objects are used to represent resource usage
+ * information of running tasks.
+ *
+ * @opensearch.internal
+ */
+public class TaskResourceUsage implements Writeable, ToXContentFragment {
+    private static final ParseField CPU_TIME_IN_NANOS = new ParseField("cpu_time_in_nanos");
+    private static final ParseField MEMORY_IN_BYTES = new ParseField("memory_in_bytes");
+
+    private final long cpuTimeInNanos;
+    private final long memoryInBytes;
+
+    public TaskResourceUsage(long cpuTimeInNanos, long memoryInBytes) {
+        this.cpuTimeInNanos = cpuTimeInNanos;
+        this.memoryInBytes = memoryInBytes;
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public static TaskResourceUsage readFromStream(StreamInput in) throws IOException {
+        return new TaskResourceUsage(in.readVLong(), in.readVLong());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(cpuTimeInNanos);
+        out.writeVLong(memoryInBytes);
+    }
+
+    public long getCpuTimeInNanos() {
+        return cpuTimeInNanos;
+    }
+
+    public long getMemoryInBytes() {
+        return memoryInBytes;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(CPU_TIME_IN_NANOS.getPreferredName(), cpuTimeInNanos);
+        builder.field(MEMORY_IN_BYTES.getPreferredName(), memoryInBytes);
+        return builder;
+    }
+
+    public static final ConstructingObjectParser<TaskResourceUsage, Void> PARSER = new ConstructingObjectParser<>(
+        "task_resource_usage",
+        a -> new TaskResourceUsage((Long) a[0], (Long) a[1])
+    );
+
+    static {
+        PARSER.declareLong(constructorArg(), CPU_TIME_IN_NANOS);
+        PARSER.declareLong(constructorArg(), MEMORY_IN_BYTES);
+    }
+
+    public static TaskResourceUsage fromXContent(XContentParser parser) {
+        return PARSER.apply(parser, null);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
+    }
+
+    // Implements equals and hashcode for testing
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null || obj.getClass() != TaskResourceUsage.class) {
+            return false;
+        }
+        TaskResourceUsage other = (TaskResourceUsage) obj;
+        return Objects.equals(cpuTimeInNanos, other.cpuTimeInNanos) && Objects.equals(memoryInBytes, other.memoryInBytes);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(cpuTimeInNanos, memoryInBytes);
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskThreadUsage.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskThreadUsage.java
new file mode 100644
index 0000000000000..b593ec96e5996
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/TaskThreadUsage.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * Task thread execution information.
+ * Writeable TaskThreadExecutions objects are used to represent thread related resource usage of running tasks.
+ * asd
+ *
+ * @opensearch.internal
+ */
+public class TaskThreadUsage implements Writeable, ToXContentFragment {
+
+    private static final String THREAD_EXECUTIONS = "thread_executions";
+    private static final String ACTIVE_THREADS = "active_threads";
+    private static final ParseField THREAD_EXECUTION_COUNT = new ParseField(THREAD_EXECUTIONS);
+    private static final ParseField ACTIVE_THREAD_COUNT = new ParseField(ACTIVE_THREADS);
+
+    private final int threadExecutions;
+    private final int activeThreads;
+
+    public TaskThreadUsage(int threadExecutions, int activeThreads) {
+        this.threadExecutions = threadExecutions;
+        this.activeThreads = activeThreads;
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public static TaskThreadUsage readFromStream(StreamInput in) throws IOException {
+        return new TaskThreadUsage(in.readInt(), in.readInt());
+    }
+
+    public int getThreadExecutions() {
+        return threadExecutions;
+    }
+
+    public int getActiveThreads() {
+        return activeThreads;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(THREAD_EXECUTIONS, threadExecutions);
+        builder.field(ACTIVE_THREADS, activeThreads);
+        return builder;
+    }
+
+    public static final ConstructingObjectParser<TaskThreadUsage, Void> PARSER = new ConstructingObjectParser<>(
+        "task_thread_executions",
+        a -> new TaskThreadUsage((int) a[0], (int) a[1])
+    );
+
+    static {
+        PARSER.declareInt(constructorArg(), THREAD_EXECUTION_COUNT);
+        PARSER.declareInt(constructorArg(), ACTIVE_THREAD_COUNT);
+    }
+
+    public static TaskThreadUsage fromXContent(XContentParser parser) {
+        return PARSER.apply(parser, null);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeInt(threadExecutions);
+        out.writeInt(activeThreads);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null || obj.getClass() != TaskThreadUsage.class) {
+            return false;
+        }
+        TaskThreadUsage other = (TaskThreadUsage) obj;
+        return Objects.equals(threadExecutions, other.threadExecutions) && Objects.equals(activeThreads, other.activeThreads);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(threadExecutions, activeThreads);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ThreadResourceInfo.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ThreadResourceInfo.java
new file mode 100644
index 0000000000000..4b341a94256c4
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/ThreadResourceInfo.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.tasks.resourcetracker;
+
+/**
+ * Resource consumption information about a particular execution of thread.
+ * <p>
+ * It captures the resource usage information about a particular execution of thread
+ * for a specific stats type like worker_stats or response_stats etc.,
+ *
+ * @opensearch.internal
+ */
+public class ThreadResourceInfo {
+    private final long threadId;
+    private volatile boolean isActive = true;
+    private final ResourceStatsType statsType;
+    private final ResourceUsageInfo resourceUsageInfo;
+
+    public ThreadResourceInfo(long threadId, ResourceStatsType statsType, ResourceUsageMetric... resourceUsageMetrics) {
+        this.threadId = threadId;
+        this.statsType = statsType;
+        this.resourceUsageInfo = new ResourceUsageInfo(resourceUsageMetrics);
+    }
+
+    /**
+     * Updates thread's resource consumption information.
+     */
+    public void recordResourceUsageMetrics(ResourceUsageMetric... resourceUsageMetrics) {
+        resourceUsageInfo.recordResourceUsageMetrics(resourceUsageMetrics);
+    }
+
+    public void setActive(boolean isActive) {
+        this.isActive = isActive;
+    }
+
+    public boolean isActive() {
+        return isActive;
+    }
+
+    public ResourceStatsType getStatsType() {
+        return statsType;
+    }
+
+    public long getThreadId() {
+        return threadId;
+    }
+
+    public ResourceUsageInfo getResourceUsageInfo() {
+        return resourceUsageInfo;
+    }
+
+    @Override
+    public String toString() {
+        return resourceUsageInfo + ", stats_type=" + statsType + ", is_active=" + isActive + ", threadId=" + threadId;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/package-info.java b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/package-info.java
new file mode 100644
index 0000000000000..b46b685ffaaf0
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/tasks/resourcetracker/package-info.java
@@ -0,0 +1,9 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+/** Resource tracking classes for tracking task resource consumption (e.g., memory, cpu) */
+package org.opensearch.core.tasks.resourcetracker;
diff --git a/server/src/main/java/org/opensearch/transport/TransportMessage.java b/libs/core/src/main/java/org/opensearch/core/transport/TransportMessage.java
similarity index 85%
rename from server/src/main/java/org/opensearch/transport/TransportMessage.java
rename to libs/core/src/main/java/org/opensearch/core/transport/TransportMessage.java
index 0862e25205261..941babda40aa3 100644
--- a/server/src/main/java/org/opensearch/transport/TransportMessage.java
+++ b/libs/core/src/main/java/org/opensearch/core/transport/TransportMessage.java
@@ -30,12 +30,17 @@
  * GitHub history for details.
  */
 
-package org.opensearch.transport;
+package org.opensearch.core.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
 
+/**
+ * Message over the transport interface
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportMessage implements Writeable {
 
     private TransportAddress remoteAddress;
diff --git a/server/src/main/java/org/opensearch/transport/TransportResponse.java b/libs/core/src/main/java/org/opensearch/core/transport/TransportResponse.java
similarity index 86%
rename from server/src/main/java/org/opensearch/transport/TransportResponse.java
rename to libs/core/src/main/java/org/opensearch/core/transport/TransportResponse.java
index 7369f5475926b..038069e93a51b 100644
--- a/server/src/main/java/org/opensearch/transport/TransportResponse.java
+++ b/libs/core/src/main/java/org/opensearch/core/transport/TransportResponse.java
@@ -30,13 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.transport;
+package org.opensearch.core.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Response over the transport interface
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportResponse extends TransportMessage {
 
     /**
@@ -53,6 +58,11 @@ public TransportResponse(StreamInput in) throws IOException {
         super(in);
     }
 
+    /**
+     * Empty transport response
+     *
+     * @opensearch.internal
+     */
     public static class Empty extends TransportResponse {
         public static final Empty INSTANCE = new Empty();
 
diff --git a/libs/core/src/main/java/org/opensearch/core/transport/package-info.java b/libs/core/src/main/java/org/opensearch/core/transport/package-info.java
new file mode 100644
index 0000000000000..91db839f40305
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/transport/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core Transport Layer classes used across the OpenSearch core */
+package org.opensearch.core.transport;
diff --git a/libs/core/src/main/java/org/opensearch/core/util/BytesRefUtils.java b/libs/core/src/main/java/org/opensearch/core/util/BytesRefUtils.java
new file mode 100644
index 0000000000000..30c9f182fcae6
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/util/BytesRefUtils.java
@@ -0,0 +1,114 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.util;
+
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.BytesRefArray;
+import org.apache.lucene.util.BytesRefBuilder;
+import org.apache.lucene.util.InPlaceMergeSorter;
+
+import java.util.Comparator;
+
+/**
+ * Utilities for sorting Lucene {@link BytesRefArray}
+ *
+ * @opensearch.internal
+ */
+public class BytesRefUtils {
+    public static void sort(final BytesRefArray bytes, final int[] indices) {
+        sort(new BytesRefBuilder(), new BytesRefBuilder(), bytes, indices);
+    }
+
+    private static void sort(
+        final BytesRefBuilder scratch,
+        final BytesRefBuilder scratch1,
+        final BytesRefArray bytes,
+        final int[] indices
+    ) {
+
+        final int numValues = bytes.size();
+        assert indices.length >= numValues;
+        if (numValues > 1) {
+            new InPlaceMergeSorter() {
+                final Comparator<BytesRef> comparator = Comparator.naturalOrder();
+
+                @Override
+                protected int compare(int i, int j) {
+                    return comparator.compare(bytes.get(scratch, indices[i]), bytes.get(scratch1, indices[j]));
+                }
+
+                @Override
+                protected void swap(int i, int j) {
+                    int value_i = indices[i];
+                    indices[i] = indices[j];
+                    indices[j] = value_i;
+                }
+            }.sort(0, numValues);
+        }
+
+    }
+
+    public static int sortAndDedup(final BytesRefArray bytes, final int[] indices) {
+        final BytesRefBuilder scratch = new BytesRefBuilder();
+        final BytesRefBuilder scratch1 = new BytesRefBuilder();
+        final int numValues = bytes.size();
+        assert indices.length >= numValues;
+        if (numValues <= 1) {
+            return numValues;
+        }
+        sort(scratch, scratch1, bytes, indices);
+        int uniqueCount = 1;
+        BytesRefBuilder previous = scratch;
+        BytesRefBuilder current = scratch1;
+        bytes.get(previous, indices[0]);
+        for (int i = 1; i < numValues; ++i) {
+            bytes.get(current, indices[i]);
+            if (!previous.get().equals(current.get())) {
+                indices[uniqueCount++] = indices[i];
+            }
+            BytesRefBuilder tmp = previous;
+            previous = current;
+            current = tmp;
+        }
+        return uniqueCount;
+    }
+
+    public static long bytesToLong(BytesRef bytes) {
+        int high = (bytes.bytes[bytes.offset + 0] << 24) | ((bytes.bytes[bytes.offset + 1] & 0xff) << 16) | ((bytes.bytes[bytes.offset + 2]
+            & 0xff) << 8) | (bytes.bytes[bytes.offset + 3] & 0xff);
+        int low = (bytes.bytes[bytes.offset + 4] << 24) | ((bytes.bytes[bytes.offset + 5] & 0xff) << 16) | ((bytes.bytes[bytes.offset + 6]
+            & 0xff) << 8) | (bytes.bytes[bytes.offset + 7] & 0xff);
+        return (((long) high) << 32) | (low & 0x0ffffffffL);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/common/io/FileSystemUtils.java b/libs/core/src/main/java/org/opensearch/core/util/FileSystemUtils.java
similarity index 97%
rename from server/src/main/java/org/opensearch/common/io/FileSystemUtils.java
rename to libs/core/src/main/java/org/opensearch/core/util/FileSystemUtils.java
index e8ba699f61e7a..99f48ed49dd39 100644
--- a/server/src/main/java/org/opensearch/common/io/FileSystemUtils.java
+++ b/libs/core/src/main/java/org/opensearch/core/util/FileSystemUtils.java
@@ -30,13 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io;
+package org.opensearch.core.util;
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -48,6 +47,8 @@
 
 /**
  * OpenSearch utils to work with {@link java.nio.file.Path}
+ *
+ * @opensearch.internal
  */
 public final class FileSystemUtils {
 
@@ -149,7 +150,7 @@ public static InputStream openFileURLStream(URL url) throws IOException {
         if ("file".equals(protocol) == false && "jar".equals(protocol) == false) {
             throw new IllegalArgumentException("Invalid protocol [" + protocol + "], must be [file] or [jar]");
         }
-        if (Strings.isEmpty(url.getHost()) == false) {
+        if (url.getHost().isEmpty() == false) {
             throw new IllegalArgumentException("URL cannot have host. Found: [" + url.getHost() + ']');
         }
         if (url.getPort() != -1) {
diff --git a/libs/core/src/main/java/org/opensearch/core/util/package-info.java b/libs/core/src/main/java/org/opensearch/core/util/package-info.java
new file mode 100644
index 0000000000000..deab57b120644
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/util/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core utility classes that need the Lucene API */
+package org.opensearch.core.util;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/AbstractObjectParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/AbstractObjectParser.java
similarity index 98%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/AbstractObjectParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/AbstractObjectParser.java
index ee6221a4f94b6..a0e2a54fce91c 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/AbstractObjectParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/AbstractObjectParser.java
@@ -30,12 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -46,6 +46,8 @@
 
 /**
  * Superclass for {@link ObjectParser} and {@link ConstructingObjectParser}. Defines most of the "declare" methods so they can be shared.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractObjectParser<Value, Context> {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/AbstractXContentParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/AbstractXContentParser.java
similarity index 85%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/support/AbstractXContentParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/AbstractXContentParser.java
index 369e8edc82965..4efaacecd0e67 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/AbstractXContentParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/AbstractXContentParser.java
@@ -30,17 +30,13 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent.support;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.Numbers;
 
 import java.io.IOException;
-import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.nio.CharBuffer;
 import java.util.ArrayList;
@@ -50,6 +46,11 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
+/**
+ * Base class for parsing serializable content
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractXContentParser implements XContentParser {
 
     // Currently this is not a setting that can be changed and is a policy
@@ -92,6 +93,18 @@ void ensureNumberConversion(boolean coerce, long result, Class<? extends Number>
         }
     }
 
+    void ensureNumberConversion(boolean coerce, BigInteger result, Class<? extends Number> clazz) throws IOException {
+        if (!coerce) {
+            double fullVal = doDoubleValue();
+            if (result.doubleValue() != fullVal) {
+                // Need to throw type IllegalArgumentException as current catch
+                // logic in NumberFieldMapper.parseCreateField relies on this
+                // for "malformed" value detection
+                throw new IllegalArgumentException(fullVal + " cannot be converted to " + clazz.getSimpleName() + " without data loss");
+            }
+        }
+    }
+
     @Override
     public boolean isBooleanValue() throws IOException {
         switch (currentToken()) {
@@ -166,44 +179,6 @@ public int intValue(boolean coerce) throws IOException {
 
     protected abstract int doIntValue() throws IOException;
 
-    private static BigInteger LONG_MAX_VALUE_AS_BIGINTEGER = BigInteger.valueOf(Long.MAX_VALUE);
-    private static BigInteger LONG_MIN_VALUE_AS_BIGINTEGER = BigInteger.valueOf(Long.MIN_VALUE);
-    // weak bounds on the BigDecimal representation to allow for coercion
-    private static BigDecimal BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE = BigDecimal.valueOf(Long.MAX_VALUE).add(BigDecimal.ONE);
-    private static BigDecimal BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE = BigDecimal.valueOf(Long.MIN_VALUE).subtract(BigDecimal.ONE);
-
-    /** Return the long that {@code stringValue} stores or throws an exception if the
-     *  stored value cannot be converted to a long that stores the exact same
-     *  value and {@code coerce} is false. */
-    private static long toLong(String stringValue, boolean coerce) {
-        try {
-            return Long.parseLong(stringValue);
-        } catch (NumberFormatException e) {
-            // we will try again with BigDecimal
-        }
-
-        final BigInteger bigIntegerValue;
-        try {
-            final BigDecimal bigDecimalValue = new BigDecimal(stringValue);
-            if (bigDecimalValue.compareTo(BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE) >= 0
-                || bigDecimalValue.compareTo(BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE) <= 0) {
-                throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
-            }
-            bigIntegerValue = coerce ? bigDecimalValue.toBigInteger() : bigDecimalValue.toBigIntegerExact();
-        } catch (ArithmeticException e) {
-            throw new IllegalArgumentException("Value [" + stringValue + "] has a decimal part");
-        } catch (NumberFormatException e) {
-            throw new IllegalArgumentException("For input string: \"" + stringValue + "\"");
-        }
-
-        if (bigIntegerValue.compareTo(LONG_MAX_VALUE_AS_BIGINTEGER) > 0 || bigIntegerValue.compareTo(LONG_MIN_VALUE_AS_BIGINTEGER) < 0) {
-            throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
-        }
-
-        assert bigIntegerValue.longValueExact() <= Long.MAX_VALUE; // asserting that no ArithmeticException is thrown
-        return bigIntegerValue.longValue();
-    }
-
     @Override
     public long longValue() throws IOException {
         return longValue(DEFAULT_NUMBER_COERCE_POLICY);
@@ -214,7 +189,7 @@ public long longValue(boolean coerce) throws IOException {
         Token token = currentToken();
         if (token == Token.VALUE_STRING) {
             checkCoerceString(coerce, Long.class);
-            return toLong(text(), coerce);
+            return Numbers.toLong(text(), coerce);
         }
         long result = doLongValue();
         ensureNumberConversion(coerce, result, Long.class);
@@ -257,6 +232,25 @@ public double doubleValue(boolean coerce) throws IOException {
 
     protected abstract double doDoubleValue() throws IOException;
 
+    @Override
+    public BigInteger bigIntegerValue() throws IOException {
+        return bigIntegerValue(DEFAULT_NUMBER_COERCE_POLICY);
+    }
+
+    @Override
+    public BigInteger bigIntegerValue(boolean coerce) throws IOException {
+        Token token = currentToken();
+        if (token == Token.VALUE_STRING) {
+            checkCoerceString(coerce, BigInteger.class);
+            return Numbers.toUnsignedLong(text(), coerce);
+        }
+        BigInteger result = doBigIntegerValue();
+        ensureNumberConversion(coerce, result, BigInteger.class);
+        return result;
+    }
+
+    protected abstract BigInteger doBigIntegerValue() throws IOException;
+
     @Override
     public final String textOrNull() throws IOException {
         if (currentToken() == Token.VALUE_NULL) {
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ConstructingObjectParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ConstructingObjectParser.java
similarity index 99%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ConstructingObjectParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ConstructingObjectParser.java
index 232977b34c62c..33ef0848599f9 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ConstructingObjectParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ConstructingObjectParser.java
@@ -30,11 +30,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -85,6 +85,8 @@
  * <p>
  * Note: if optional constructor arguments aren't specified then the number of allocations is always the worst case.
  * </p>
+ *
+ * @opensearch.internal
  */
 public final class ConstructingObjectParser<Value, Context> extends AbstractObjectParser<Value, Context>
     implements
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ContextParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ContextParser.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ContextParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ContextParser.java
index 62bcc3a0e8f33..d50dd2e68d890 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ContextParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ContextParser.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.io.IOException;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/DeprecationHandler.java b/libs/core/src/main/java/org/opensearch/core/xcontent/DeprecationHandler.java
similarity index 99%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/DeprecationHandler.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/DeprecationHandler.java
index e30a21c2f9013..570a13ad8e093 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/DeprecationHandler.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/DeprecationHandler.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.util.function.Supplier;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ErrorOnUnknown.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ErrorOnUnknown.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ErrorOnUnknown.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ErrorOnUnknown.java
index bff2c7a0033bb..a03265ab47114 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ErrorOnUnknown.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ErrorOnUnknown.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.util.ServiceLoader;
 
@@ -38,6 +38,8 @@
  * Extension point to customize the error message for unknown fields. We expect
  * OpenSearch to plug a fancy implementation that uses Lucene's spelling
  * correction infrastructure to suggest corrections.
+ *
+ * @opensearch.api
  */
 public interface ErrorOnUnknown {
     /**
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/InstantiatingObjectParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/InstantiatingObjectParser.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/InstantiatingObjectParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/InstantiatingObjectParser.java
index f583fb87816da..0d6e268592275 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/InstantiatingObjectParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/InstantiatingObjectParser.java
@@ -30,9 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 
 import java.io.IOException;
 import java.lang.reflect.Constructor;
@@ -73,6 +73,8 @@
  *       PARSER.finalizeFields()
  *   }
  * }</pre>
+ *
+ * @opensearch.internal
  */
 public class InstantiatingObjectParser<Value, Context>
     implements
@@ -87,6 +89,11 @@ public static <Value, Context> Builder<Value, Context> builder(String name, Clas
         return new Builder<>(name, valueClass);
     }
 
+    /**
+     * Builder for the Instantiating Object Parser
+     *
+     * @opensearch.internal
+     **/
     public static class Builder<Value, Context> extends AbstractObjectParser<Value, Context> {
 
         private final ConstructingObjectParser<Value, Context> constructingObjectParser;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/MapXContentParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/MapXContentParser.java
similarity index 96%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/support/MapXContentParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/MapXContentParser.java
index b96a3f1db403b..254c340f8836f 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/MapXContentParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/MapXContentParser.java
@@ -30,12 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent.support;
-
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentType;
+package org.opensearch.core.xcontent;
 
 import java.io.IOException;
 import java.math.BigDecimal;
@@ -50,7 +45,7 @@
  */
 public class MapXContentParser extends AbstractXContentParser {
 
-    private XContentType xContentType;
+    private MediaType mediaType;
     private TokenIterator iterator;
     private boolean closed;
 
@@ -58,10 +53,10 @@ public MapXContentParser(
         NamedXContentRegistry xContentRegistry,
         DeprecationHandler deprecationHandler,
         Map<String, Object> map,
-        XContentType xContentType
+        MediaType mediaType
     ) {
         super(xContentRegistry, deprecationHandler);
-        this.xContentType = xContentType;
+        this.mediaType = mediaType;
         this.iterator = new MapIterator(null, null, map);
     }
 
@@ -100,8 +95,17 @@ protected double doDoubleValue() throws IOException {
     }
 
     @Override
-    public XContentType contentType() {
-        return xContentType;
+    protected BigInteger doBigIntegerValue() throws IOException {
+        if (numberValue() instanceof BigInteger) {
+            return (BigInteger) numberValue();
+        } else {
+            return BigInteger.valueOf(numberValue().longValue());
+        }
+    }
+
+    @Override
+    public MediaType contentType() {
+        return mediaType;
     }
 
     @Override
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/MediaType.java b/libs/core/src/main/java/org/opensearch/core/xcontent/MediaType.java
new file mode 100644
index 0000000000000..c58b3e80d98b5
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/MediaType.java
@@ -0,0 +1,128 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.xcontent;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Locale;
+
+/**
+ * Abstracts a <a href="http://en.wikipedia.org/wiki/Internet_media_type">Media Type</a> and a format parameter.
+ * Media types are used as values on Content-Type and Accept headers
+ * format is an URL parameter, specifies response media type.
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "2.1.0")
+public interface MediaType extends Writeable {
+    /**
+     * Returns a type part of a MediaType
+     * i.e. application for application/json
+     */
+    String type();
+
+    /**
+     * Returns a subtype part of a MediaType.
+     * i.e. json for application/json
+     */
+    String subtype();
+
+    /**
+     * Returns a corresponding format for a MediaType. i.e. json for application/json media type
+     * Can differ from the MediaType's subtype i.e plain/text has a subtype of text but format is txt
+     */
+    String format();
+
+    /**
+     * returns a string representation of a media type.
+     */
+    default String typeWithSubtype() {
+        return type() + "/" + subtype();
+    }
+
+    XContent xContent();
+
+    boolean detectedXContent(final byte[] bytes, int offset, int length);
+
+    boolean detectedXContent(final CharSequence content, final int length);
+
+    default String mediaType() {
+        return mediaTypeWithoutParameters();
+    }
+
+    String mediaTypeWithoutParameters();
+
+    XContentBuilder contentBuilder() throws IOException;
+
+    XContentBuilder contentBuilder(final OutputStream os) throws IOException;
+
+    /**
+     * Accepts a format string, which is most of the time is equivalent to {@link MediaType#subtype()}
+     * and attempts to match the value to an {@link MediaType}.
+     * The comparisons are done in lower case format.
+     * This method will return {@code null} if no match is found
+     */
+    static MediaType fromFormat(String mediaType) {
+        return MediaTypeRegistry.fromFormat(mediaType);
+    }
+
+    /**
+     * Attempts to match the given media type with the known {@link MediaType} values. This match is done in a case-insensitive manner.
+     * The provided media type can optionally has parameters.
+     * This method is suitable for parsing of the {@code Content-Type} and {@code Accept} HTTP headers.
+     * This method will return {@code null} if no match is found
+     */
+    static MediaType fromMediaType(String mediaTypeHeaderValue) {
+        mediaTypeHeaderValue = removeVersionInMediaType(mediaTypeHeaderValue);
+        return MediaTypeRegistry.fromMediaType(mediaTypeHeaderValue);
+    }
+
+    /**
+     * Clients compatible with ES 7.x might start sending media types with versioned media type
+     * in a form of application/vnd.elasticsearch+json;compatible-with=7.
+     * This has to be removed in order to be used in 7.x server.
+     * The same client connecting using that media type will be able to communicate with ES 8 thanks to compatible API.
+     * @param mediaType - a media type used on Content-Type header, might contain versioned media type.
+     *
+     * @return a media type string without
+     */
+    private static String removeVersionInMediaType(String mediaType) {
+        if (mediaType != null && (mediaType = mediaType.toLowerCase(Locale.ROOT)).contains("vnd.opensearch")) {
+            return mediaType.replaceAll("vnd.opensearch\\+", "").replaceAll("\\s*;\\s*compatible-with=\\d+", "");
+        }
+        return mediaType;
+    }
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/MediaTypeRegistry.java b/libs/core/src/main/java/org/opensearch/core/xcontent/MediaTypeRegistry.java
new file mode 100644
index 0000000000000..bbb55204712d1
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/MediaTypeRegistry.java
@@ -0,0 +1,405 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.core.xcontent;
+
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.spi.MediaTypeProvider;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.UncheckedIOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Parses supported internet media types
+ *
+ * @opensearch.internal
+ */
+public final class MediaTypeRegistry {
+    private static Map<String, MediaType> formatToMediaType = Map.of();
+    private static Map<String, MediaType> typeWithSubtypeToMediaType = Map.of();
+
+    // Default mediaType singleton
+    private static MediaType DEFAULT_MEDIA_TYPE;
+    public static final int GUESS_HEADER_LENGTH = 20;
+
+    // JSON is a core type, so we create a static instance for implementations that require JSON format (e.g., tests)
+    // todo we should explore moving the concrete JSON implementation from the xcontent library to core
+    public static final MediaType JSON;
+
+    static {
+        List<MediaType> mediaTypes = new ArrayList<>();
+        Map<String, MediaType> amt = new HashMap<>();
+        for (MediaTypeProvider provider : ServiceLoader.load(MediaTypeProvider.class, MediaTypeProvider.class.getClassLoader())) {
+            mediaTypes.addAll(provider.getMediaTypes());
+            amt = Stream.of(amt, provider.getAdditionalMediaTypes())
+                .flatMap(map -> map.entrySet().stream())
+                .collect(Collectors.toUnmodifiableMap(Map.Entry::getKey, Map.Entry::getValue));
+        }
+        register(mediaTypes.toArray(new MediaType[0]), amt);
+        JSON = fromMediaType("application/json");
+        setDefaultMediaType(JSON);
+    }
+
+    private static void register(MediaType[] acceptedMediaTypes, Map<String, MediaType> additionalMediaTypes) {
+        // ensures the map is not overwritten:
+        Map<String, MediaType> typeMap = new HashMap<>(typeWithSubtypeToMediaType);
+        Map<String, MediaType> formatMap = new HashMap<>(formatToMediaType);
+        for (MediaType mediaType : acceptedMediaTypes) {
+            if (formatMap.containsKey(mediaType.format())) {
+                throw new IllegalArgumentException("unable to register mediaType: [" + mediaType.format() + "]. Type already exists.");
+            }
+            typeMap.put(mediaType.typeWithSubtype(), mediaType);
+            formatMap.put(mediaType.format(), mediaType);
+        }
+        for (Map.Entry<String, MediaType> entry : additionalMediaTypes.entrySet()) {
+            String typeWithSubtype = entry.getKey().toLowerCase(Locale.ROOT);
+            if (typeMap.containsKey(typeWithSubtype)) {
+                throw new IllegalArgumentException(
+                    "unable to register mediaType: ["
+                        + entry.getKey()
+                        + "]. "
+                        + "Type already exists and is mapped to: [."
+                        + entry.getValue().format()
+                        + "]"
+                );
+            }
+
+            MediaType mediaType = entry.getValue();
+            typeMap.put(typeWithSubtype, mediaType);
+            formatMap.putIfAbsent(mediaType.format(), mediaType); // ignore if the additional type mapping already exists
+        }
+
+        formatToMediaType = Map.copyOf(formatMap);
+        typeWithSubtypeToMediaType = Map.copyOf(typeMap);
+    }
+
+    public static MediaType fromMediaType(String mediaType) {
+        ParsedMediaType parsedMediaType = parseMediaType(mediaType);
+        return parsedMediaType != null ? parsedMediaType.getMediaType() : null;
+    }
+
+    public static MediaType fromFormat(String format) {
+        if (format == null) {
+            return null;
+        }
+        return formatToMediaType.get(format.toLowerCase(Locale.ROOT));
+    }
+
+    /**
+     * Returns a binary content builder for the provided content type.
+     */
+    public static XContentBuilder contentBuilder(MediaType type) throws IOException {
+        for (var mediaType : formatToMediaType.values()) {
+            if (type == mediaType) {
+                return type.contentBuilder();
+            }
+        }
+        throw new IllegalArgumentException("No matching content type for " + type);
+    }
+
+    public static XContentBuilder contentBuilder(MediaType type, OutputStream outputStream) throws IOException {
+        for (var mediaType : formatToMediaType.values()) {
+            if (type == mediaType) {
+                return type.contentBuilder(outputStream);
+            }
+        }
+        throw new IllegalArgumentException("No matching content type for " + type);
+    }
+
+    /**
+     * Guesses the content (type) based on the provided char sequence and returns the corresponding {@link XContent}
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContent(final byte[] data, int offset, int length) {
+        MediaType type = mediaTypeFromBytes(data, offset, length);
+        if (type == null) {
+            throw new XContentParseException("Failed to derive xcontent");
+        }
+        return type;
+    }
+
+    /**
+     * Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContent(byte[] data) {
+        return xContent(data, 0, data.length);
+    }
+
+    /**
+     * Guesses the content (type) based on the provided char sequence and returns the corresponding {@link XContent}
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContent(CharSequence content) {
+        MediaType type = xContentType(content);
+        if (type == null) {
+            throw new XContentParseException("Failed to derive xcontent");
+        }
+        return type;
+    }
+
+    /**
+     * Guesses the content type based on the provided char sequence.
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContentType(CharSequence content) {
+        int length = content.length() < GUESS_HEADER_LENGTH ? content.length() : GUESS_HEADER_LENGTH;
+        if (length == 0) {
+            return null;
+        }
+        for (var mediaType : formatToMediaType.values()) {
+            if (mediaType.detectedXContent(content, length)) {
+                return mediaType;
+            }
+        }
+
+        // fallback for json
+        for (int i = 0; i < length; i++) {
+            char c = content.charAt(i);
+            if (c == '{') {
+                return MediaType.fromMediaType("application/json");
+            }
+            if (Character.isWhitespace(c) == false) {
+                break;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Guesses the content type based on the provided input stream without consuming it.
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContentType(InputStream si) throws IOException {
+        /*
+         * We need to guess the content type. To do this, we look for the first non-whitespace character and then try to guess the content
+         * type on the GUESS_HEADER_LENGTH bytes that follow. We do this in a way that does not modify the initial read position in the
+         * underlying input stream. This is why the input stream must support mark/reset and why we repeatedly mark the read position and
+         * reset.
+         */
+        if (si.markSupported() == false) {
+            throw new IllegalArgumentException("Cannot guess the xcontent type without mark/reset support on " + si.getClass());
+        }
+        si.mark(Integer.MAX_VALUE);
+        try {
+            // scan until we find the first non-whitespace character or the end of the stream
+            int current;
+            do {
+                current = si.read();
+                if (current == -1) {
+                    return null;
+                }
+            } while (Character.isWhitespace((char) current));
+            // now guess the content type off the next GUESS_HEADER_LENGTH bytes including the current byte
+            final byte[] firstBytes = new byte[GUESS_HEADER_LENGTH];
+            firstBytes[0] = (byte) current;
+            int read = 1;
+            while (read < GUESS_HEADER_LENGTH) {
+                final int r = si.read(firstBytes, read, GUESS_HEADER_LENGTH - read);
+                if (r == -1) {
+                    break;
+                }
+                read += r;
+            }
+            return mediaTypeFromBytes(firstBytes, 0, read);
+        } finally {
+            si.reset();
+        }
+
+    }
+
+    /**
+     * Guesses the content type based on the provided bytes.
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType xContentType(BytesReference bytes) {
+        if (bytes instanceof BytesArray) {
+            final BytesArray array = (BytesArray) bytes;
+            return mediaTypeFromBytes(array.array(), array.offset(), array.length());
+        }
+        try {
+            final InputStream inputStream = bytes.streamInput();
+            assert inputStream.markSupported();
+            return xContentType(inputStream);
+        } catch (IOException e) {
+            assert false : "Should not happen, we're just reading bytes from memory";
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    /**
+     * Guesses the content type based on the provided bytes.
+     *
+     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
+     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
+     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
+     */
+    @Deprecated
+    public static MediaType mediaTypeFromBytes(final byte[] data, int offset, int length) {
+        int totalLength = data.length;
+        if (totalLength == 0 || length == 0) {
+            return null;
+        } else if ((offset + length) > totalLength) {
+            return null;
+        }
+        for (var mediaType : formatToMediaType.values()) {
+            if (mediaType.detectedXContent(data, offset, length)) {
+                return mediaType;
+            }
+        }
+
+        // a last chance for JSON
+        int jsonStart = 0;
+        // JSON may be preceded by UTF-8 BOM
+        if (length > 3 && data[offset] == (byte) 0xEF && data[offset + 1] == (byte) 0xBB && data[offset + 2] == (byte) 0xBF) {
+            jsonStart = 3;
+        }
+
+        for (int i = jsonStart; i < length; i++) {
+            byte b = data[offset + i];
+            if (b == '{') {
+                return fromMediaType("application/json");
+            }
+            if (Character.isWhitespace(b) == false) {
+                break;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * parsing media type that follows https://tools.ietf.org/html/rfc7231#section-3.1.1.1
+     * @param headerValue a header value from Accept or Content-Type
+     * @return a parsed media-type
+     */
+    public static ParsedMediaType parseMediaType(String headerValue) {
+        if (headerValue != null) {
+            String[] split = headerValue.toLowerCase(Locale.ROOT).split(";");
+
+            String[] typeSubtype = split[0].trim().split("/");
+            if (typeSubtype.length == 2) {
+                String type = typeSubtype[0];
+                String subtype = typeSubtype[1];
+                MediaType mediaType = typeWithSubtypeToMediaType.get(type + "/" + subtype);
+                if (mediaType != null) {
+                    Map<String, String> parameters = new HashMap<>();
+                    for (int i = 1; i < split.length; i++) {
+                        // spaces are allowed between parameters, but not between '=' sign
+                        String[] keyValueParam = split[i].trim().split("=");
+                        if (keyValueParam.length != 2 || hasSpaces(keyValueParam[0]) || hasSpaces(keyValueParam[1])) {
+                            return null;
+                        }
+                        parameters.put(keyValueParam[0], keyValueParam[1]);
+                    }
+                    return new ParsedMediaType(mediaType, parameters);
+                }
+            }
+
+        }
+        return null;
+    }
+
+    private static boolean hasSpaces(String s) {
+        return s.trim().equals(s) == false;
+    }
+
+    /**
+     * A media type object that contains all the information provided on a Content-Type or Accept header
+     */
+    public static class ParsedMediaType {
+        private final Map<String, String> parameters;
+        private final MediaType mediaType;
+
+        public ParsedMediaType(MediaType mediaType, Map<String, String> parameters) {
+            this.parameters = parameters;
+            this.mediaType = mediaType;
+        }
+
+        public MediaType getMediaType() {
+            return mediaType;
+        }
+
+        public Map<String, String> getParameters() {
+            return parameters;
+        }
+    }
+
+    private static void setDefaultMediaType(final MediaType mediaType) {
+        if (DEFAULT_MEDIA_TYPE != null) {
+            throw new RuntimeException(
+                "unable to reset the default media type from current default [" + DEFAULT_MEDIA_TYPE + "] to [" + mediaType + "]"
+            );
+        } else {
+            DEFAULT_MEDIA_TYPE = mediaType;
+        }
+    }
+
+    public static MediaType getDefaultMediaType() {
+        return DEFAULT_MEDIA_TYPE;
+    }
+}
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedObjectNotFoundException.java b/libs/core/src/main/java/org/opensearch/core/xcontent/NamedObjectNotFoundException.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedObjectNotFoundException.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/NamedObjectNotFoundException.java
index 7afeccb44bdd4..b9e93d886daf5 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedObjectNotFoundException.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/NamedObjectNotFoundException.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 /**
  * Thrown when {@link NamedXContentRegistry} cannot locate a named object to
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedXContentRegistry.java b/libs/core/src/main/java/org/opensearch/core/xcontent/NamedXContentRegistry.java
similarity index 96%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedXContentRegistry.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/NamedXContentRegistry.java
index a3195debf588c..9d876825c5196 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/NamedXContentRegistry.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/NamedXContentRegistry.java
@@ -30,10 +30,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.ParseField;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -46,6 +47,12 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Main registry for serializable content (e.g., field mappers, aggregations)
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class NamedXContentRegistry {
     /**
      * The empty {@link NamedXContentRegistry} for use when you are sure that you aren't going to call
@@ -59,6 +66,7 @@ public class NamedXContentRegistry {
     /**
      * An entry in the {@linkplain NamedXContentRegistry} containing the name of the object and the parser that can parse it.
      */
+    @PublicApi(since = "1.0.0")
     public static class Entry {
         /** The class that this entry can read. */
         public final Class<?> categoryClass;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParser.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParser.java
index 71c2dec930e4a..365b36c755dd2 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParser.java
@@ -29,10 +29,10 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 
 import java.io.IOException;
 import java.lang.reflect.Array;
@@ -52,13 +52,13 @@
 import java.util.function.Supplier;
 
 import static java.util.Objects.requireNonNull;
-import static org.opensearch.common.xcontent.XContentParser.Token.START_ARRAY;
-import static org.opensearch.common.xcontent.XContentParser.Token.START_OBJECT;
-import static org.opensearch.common.xcontent.XContentParser.Token.VALUE_BOOLEAN;
-import static org.opensearch.common.xcontent.XContentParser.Token.VALUE_EMBEDDED_OBJECT;
-import static org.opensearch.common.xcontent.XContentParser.Token.VALUE_NULL;
-import static org.opensearch.common.xcontent.XContentParser.Token.VALUE_NUMBER;
-import static org.opensearch.common.xcontent.XContentParser.Token.VALUE_STRING;
+import static org.opensearch.core.xcontent.XContentParser.Token.START_ARRAY;
+import static org.opensearch.core.xcontent.XContentParser.Token.START_OBJECT;
+import static org.opensearch.core.xcontent.XContentParser.Token.VALUE_BOOLEAN;
+import static org.opensearch.core.xcontent.XContentParser.Token.VALUE_EMBEDDED_OBJECT;
+import static org.opensearch.core.xcontent.XContentParser.Token.VALUE_NULL;
+import static org.opensearch.core.xcontent.XContentParser.Token.VALUE_NUMBER;
+import static org.opensearch.core.xcontent.XContentParser.Token.VALUE_STRING;
 
 /**
  * A declarative, stateless parser that turns XContent into setter calls. A single parser should be defined for each object being parsed,
@@ -82,6 +82,8 @@
  * }</pre>
  * It's highly recommended to use the high level declare methods like {@link #declareString(BiConsumer, ParseField)} instead of
  * {@link #declareField} which can be used to implement exceptional parsing operations not covered by the high level methods.
+ *
+ * @opensearch.internal
  */
 public final class ObjectParser<Value, Context> extends AbstractObjectParser<Value, Context>
     implements
@@ -386,6 +388,11 @@ public Value apply(XContentParser parser, Context context) {
         }
     }
 
+    /**
+     * Main parser interface
+     *
+     * @opensearch.internal
+     */
     public interface Parser<Value, Context> {
         void parse(XContentParser parser, Value value, Context context) throws IOException;
     }
@@ -683,6 +690,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Supported Value Types for Parsable Objects
+     *
+     * @opensearch.internal
+     */
     public enum ValueType {
         STRING(VALUE_STRING),
         STRING_OR_NULL(VALUE_STRING, VALUE_NULL),
diff --git a/server/src/main/java/org/opensearch/common/xcontent/ObjectParserHelper.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParserHelper.java
similarity index 85%
rename from server/src/main/java/org/opensearch/common/xcontent/ObjectParserHelper.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParserHelper.java
index c833fd5cedebf..b29ca9dea56c0 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/ObjectParserHelper.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectParserHelper.java
@@ -30,13 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
 
 import java.io.IOException;
 import java.util.function.BiConsumer;
@@ -44,6 +43,8 @@
 /**
  * This class provides helpers for {@link ObjectParser} that allow dealing with
  * classes outside of the xcontent dependencies.
+ *
+ * @opensearch.internal
  */
 public final class ObjectParserHelper<Value, Context> {
 
@@ -56,7 +57,7 @@ public void declareRawObject(
         final ParseField field
     ) {
         final CheckedFunction<XContentParser, BytesReference, IOException> bytesParser = p -> {
-            try (XContentBuilder builder = JsonXContent.contentBuilder()) {
+            try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
                 builder.copyCurrentStructure(p);
                 return BytesReference.bytes(builder);
             }
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectPath.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectPath.java
similarity index 98%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectPath.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ObjectPath.java
index d18fff26046a3..b1034eb66eb58 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ObjectPath.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ObjectPath.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.lang.reflect.Array;
 import java.util.List;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ParserConstructor.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ParserConstructor.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ParserConstructor.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ParserConstructor.java
index f5309eeab92b7..b88cc8bd2b175 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ParserConstructor.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ParserConstructor.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContent.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContent.java
similarity index 92%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContent.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ToXContent.java
index 1b97cf11f18da..90dd0cbfb9a1a 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContent.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContent.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.Booleans;
 
@@ -41,9 +41,16 @@
  * An interface allowing to transfer an object to "XContent" using an {@link XContentBuilder}.
  * The output may or may not be a value object. Objects implementing {@link ToXContentObject} output a valid value
  * but those that don't may or may not require emitting a startObject and an endObject.
+ *
+ * @opensearch.internal
  */
 public interface ToXContent {
 
+    /**
+     * Base parameters class
+     *
+     * @opensearch.internal
+     */
     interface Params {
         String param(String key);
 
@@ -77,6 +84,11 @@ public Boolean paramAsBoolean(String key, Boolean defaultValue) {
 
     };
 
+    /**
+     * Mapped parameter base class
+     *
+     * @opensearch.internal
+     */
     class MapParams implements Params {
 
         private final Map<String, String> params;
@@ -110,6 +122,11 @@ public Boolean paramAsBoolean(String key, Boolean defaultValue) {
         }
     }
 
+    /**
+     * Delegates mapped parameters to base Params class
+     *
+     * @opensearch.internal
+     */
     class DelegatingMapParams extends MapParams {
 
         private final Params delegate;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentFragment.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentFragment.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentFragment.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentFragment.java
index d47857c5755a5..bb3b447f54984 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentFragment.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentFragment.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 /**
  * An interface allowing to transfer an object to "XContent" using an
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentObject.java b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentObject.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentObject.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentObject.java
index b2c24a8fc4131..d9a0e795cd74d 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/ToXContentObject.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/ToXContentObject.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 /**
  * An interface allowing to transfer an object to "XContent" using an
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContent.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContent.java
similarity index 98%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContent.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContent.java
index c8a8aa1a0cfa3..dbc0041af42b5 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContent.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContent.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -46,7 +46,7 @@ public interface XContent {
     /**
      * The type this content handles and produces.
      */
-    XContentType type();
+    MediaType mediaType();
 
     byte streamSeparator();
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilder.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilder.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilder.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilder.java
index 7086cdb0fda83..a38bdd049ee88 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilder.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilder.java
@@ -30,7 +30,10 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
+
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
@@ -59,6 +62,7 @@
 /**
  * A utility to build XContent (ie json).
  */
+@PublicApi(since = "1.0.0")
 public final class XContentBuilder implements Closeable, Flushable {
 
     /**
@@ -151,6 +155,19 @@ public static XContentBuilder builder(XContent xContent, Set<String> includes, S
         DATE_TRANSFORMERS = Collections.unmodifiableMap(dateTransformers);
     }
 
+    /**
+     * Returns a string representation of the builder (only applicable for text based xcontent).
+     */
+    @Override
+    public String toString() {
+        return BytesReference.bytes(this).utf8ToString();
+    }
+
+    /**
+     * The writer interface for the serializable content builder
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface Writer {
         void write(XContentBuilder builder, Object value) throws IOException;
@@ -213,7 +230,7 @@ public XContentBuilder(XContent xContent, OutputStream os, Set<String> includes,
         this.generator = xContent.createGenerator(bos, includes, excludes);
     }
 
-    public XContentType contentType() {
+    public MediaType contentType() {
         return generator.contentType();
     }
 
@@ -985,7 +1002,7 @@ public XContentBuilder percentageField(String rawFieldName, String readableField
 
     /**
      * Writes a raw field with the value taken from the bytes in the stream
-     * @deprecated use {@link #rawField(String, InputStream, XContentType)} to avoid content type auto-detection
+     * @deprecated use {@link #rawField(String, InputStream, MediaType)} to avoid content type auto-detection
      */
     @Deprecated
     public XContentBuilder rawField(String name, InputStream value) throws IOException {
@@ -996,15 +1013,15 @@ public XContentBuilder rawField(String name, InputStream value) throws IOExcepti
     /**
      * Writes a raw field with the value taken from the bytes in the stream
      */
-    public XContentBuilder rawField(String name, InputStream value, XContentType contentType) throws IOException {
-        generator.writeRawField(name, value, contentType);
+    public XContentBuilder rawField(String name, InputStream value, MediaType mediaType) throws IOException {
+        generator.writeRawField(name, value, mediaType);
         return this;
     }
 
     /**
      * Writes a value with the source coming directly from the bytes in the stream
      */
-    public XContentBuilder rawValue(InputStream stream, XContentType contentType) throws IOException {
+    public XContentBuilder rawValue(InputStream stream, MediaType contentType) throws IOException {
         generator.writeRawValue(stream, contentType);
         return this;
     }
@@ -1032,11 +1049,11 @@ public XContentGenerator generator() {
         return this.generator;
     }
 
-    static void ensureNameNotNull(String name) {
+    public static void ensureNameNotNull(String name) {
         ensureNotNull(name, "Field name cannot be null");
     }
 
-    static void ensureNotNull(Object value, String message) {
+    public static void ensureNotNull(Object value, String message) {
         if (value == null) {
             throw new IllegalArgumentException(message);
         }
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilderExtension.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilderExtension.java
similarity index 98%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilderExtension.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilderExtension.java
index 627a0d52974bf..0535da1a584be 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentBuilderExtension.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentBuilderExtension.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.util.Map;
 import java.util.function.Function;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentGenerator.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentGenerator.java
similarity index 93%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentGenerator.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentGenerator.java
index b0dacb3826be3..ac0e374f301b7 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentGenerator.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentGenerator.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import java.io.Closeable;
 import java.io.Flushable;
@@ -39,9 +39,14 @@
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
+/**
+ * Base class to generate serializable content
+ *
+ * @opensearch.internal
+ */
 public interface XContentGenerator extends Closeable, Flushable {
 
-    XContentType contentType();
+    MediaType contentType();
 
     void usePrettyPrint();
 
@@ -109,7 +114,7 @@ public interface XContentGenerator extends Closeable, Flushable {
 
     /**
      * Writes a raw field with the value taken from the bytes in the stream
-     * @deprecated use {@link #writeRawField(String, InputStream, XContentType)} to avoid content type auto-detection
+     * @deprecated use {@link #writeRawField(String, InputStream, MediaType)} to avoid content type auto-detection
      */
     @Deprecated
     void writeRawField(String name, InputStream value) throws IOException;
@@ -117,12 +122,12 @@ public interface XContentGenerator extends Closeable, Flushable {
     /**
      * Writes a raw field with the value taken from the bytes in the stream
      */
-    void writeRawField(String name, InputStream value, XContentType xContentType) throws IOException;
+    void writeRawField(String name, InputStream value, MediaType mediaType) throws IOException;
 
     /**
      * Writes a raw value taken from the bytes in the stream
      */
-    void writeRawValue(InputStream value, XContentType xContentType) throws IOException;
+    void writeRawValue(InputStream value, MediaType mediaType) throws IOException;
 
     void copyCurrentStructure(XContentParser parser) throws IOException;
 
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/XContentHelper.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentHelper.java
new file mode 100644
index 0000000000000..a99a12273a6f0
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentHelper.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.xcontent;
+
+import org.opensearch.core.common.bytes.BytesReference;
+
+import java.io.IOException;
+
+/**
+ * Core XContent Helper Utilities
+ *
+ * @opensearch.internal
+ */
+public final class XContentHelper {
+    // no instance
+    private XContentHelper() {}
+
+    /**
+     * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
+     * {@link MediaType}. Wraps the output into a new anonymous object according to the value returned
+     * by the {@link ToXContent#isFragment()} method returns.
+     */
+    @Deprecated
+    public static BytesReference toXContent(ToXContent toXContent, MediaType mediaType, boolean humanReadable) throws IOException {
+        return toXContent(toXContent, mediaType, ToXContent.EMPTY_PARAMS, humanReadable);
+    }
+
+    /**
+     * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
+     * {@link MediaType}. Wraps the output into a new anonymous object according to the value returned
+     * by the {@link ToXContent#isFragment()} method returns.
+     */
+    public static BytesReference toXContent(ToXContent toXContent, MediaType mediaType, ToXContent.Params params, boolean humanReadable)
+        throws IOException {
+        try (XContentBuilder builder = XContentBuilder.builder(mediaType.xContent())) {
+            builder.humanReadable(humanReadable);
+            if (toXContent.isFragment()) {
+                builder.startObject();
+            }
+            toXContent.toXContent(builder, params);
+            if (toXContent.isFragment()) {
+                builder.endObject();
+            }
+            return BytesReference.bytes(builder);
+        }
+    }
+}
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentLocation.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentLocation.java
similarity index 96%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentLocation.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentLocation.java
index a6fa6000e6f3d..b17f89993eaf5 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentLocation.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentLocation.java
@@ -30,13 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 /**
  * Simple data structure representing the line and column number of a position
  * in some XContent e.g. JSON. Locations are typically used to communicate the
  * position of a parsing error to end users and consequently have line and
  * column numbers starting from 1.
+ *
+ * @opensearch.internal
  */
 public final class XContentLocation {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParseException.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParseException.java
similarity index 98%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParseException.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentParseException.java
index a022dd58a2cfc..7eb4843df514f 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParseException.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParseException.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.Nullable;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParser.java
similarity index 92%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentParser.java
index 4c924cd8a0bfb..a2f16209a5b7f 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParser.java
@@ -30,30 +30,38 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.CheckedFunction;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.math.BigInteger;
 import java.nio.CharBuffer;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
 
 /**
- * Interface for pull - parsing {@link XContent} see {@link XContentType} for supported types.
+ * Interface for pull - parsing {@link XContent} see {@code XContentType} for supported types.
  *
  * To obtain an instance of this class use the following pattern:
  *
  * <pre>
- *     XContentType xContentType = XContentType.JSON;
- *     XContentParser parser = xContentType.xContent().createParser(
+ *     MediaType mediaType = MediaTypeRegistry.JSON;
+ *     XContentParser parser = mediaType.xContent().createParser(
  *          NamedXContentRegistry.EMPTY, ParserField."{\"key\" : \"value\"}");
  * </pre>
+ *
+ * @opensearch.internal
  */
 public interface XContentParser extends Closeable {
 
+    /**
+     * Supported serializable tokens
+     *
+     * @opensearch.internal
+     */
     enum Token {
         START_OBJECT {
             @Override
@@ -129,6 +137,11 @@ public boolean isValue() {
         public abstract boolean isValue();
     }
 
+    /**
+     * Supported numeric types
+     *
+     * @opensearch.internal
+     */
     enum NumberType {
         INT,
         BIG_INTEGER,
@@ -138,7 +151,7 @@ enum NumberType {
         BIG_DECIMAL
     }
 
-    XContentType contentType();
+    MediaType contentType();
 
     Token nextToken() throws IOException;
 
@@ -218,6 +231,8 @@ <T> Map<String, T> map(Supplier<Map<String, T>> mapFactory, CheckedFunction<XCon
 
     double doubleValue(boolean coerce) throws IOException;
 
+    BigInteger bigIntegerValue(boolean coerce) throws IOException;
+
     short shortValue() throws IOException;
 
     int intValue() throws IOException;
@@ -228,6 +243,8 @@ <T> Map<String, T> map(Supplier<Map<String, T>> mapFactory, CheckedFunction<XCon
 
     double doubleValue() throws IOException;
 
+    BigInteger bigIntegerValue() throws IOException;
+
     /**
      * @return true iff the current value is either boolean (<code>true</code> or <code>false</code>) or one of "false", "true".
      */
diff --git a/server/src/main/java/org/opensearch/common/xcontent/XContentParserUtils.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParserUtils.java
similarity index 96%
rename from server/src/main/java/org/opensearch/common/xcontent/XContentParserUtils.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentParserUtils.java
index 822210ffc1898..13e2f6a695d1b 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/XContentParserUtils.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentParserUtils.java
@@ -30,12 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -44,6 +44,8 @@
 /**
  * A set of static methods to get {@link Token} from {@link XContentParser}
  * while checking for their types and throw {@link ParsingException} if needed.
+ *
+ * @opensearch.internal
  */
 public final class XContentParserUtils {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentSubParser.java b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentSubParser.java
similarity index 94%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentSubParser.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/XContentSubParser.java
index 62d7661892e2f..d1cdda4aeb8be 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentSubParser.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/XContentSubParser.java
@@ -30,11 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent;
+package org.opensearch.core.xcontent;
 
 import org.opensearch.common.CheckedFunction;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.nio.CharBuffer;
 import java.util.List;
 import java.util.Map;
@@ -62,7 +63,7 @@ public XContentSubParser(XContentParser parser) {
     }
 
     @Override
-    public XContentType contentType() {
+    public MediaType contentType() {
         return parser.contentType();
     }
 
@@ -219,7 +220,12 @@ public float floatValue(boolean coerce) throws IOException {
 
     @Override
     public double doubleValue(boolean coerce) throws IOException {
-        return parser.doubleValue();
+        return parser.doubleValue(coerce);
+    }
+
+    @Override
+    public BigInteger bigIntegerValue(boolean coerce) throws IOException {
+        return parser.bigIntegerValue(coerce);
     }
 
     @Override
@@ -247,6 +253,11 @@ public double doubleValue() throws IOException {
         return parser.doubleValue();
     }
 
+    @Override
+    public BigInteger bigIntegerValue() throws IOException {
+        return parser.bigIntegerValue();
+    }
+
     @Override
     public boolean isBooleanValue() throws IOException {
         return parser.isBooleanValue();
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPath.java b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPath.java
similarity index 97%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPath.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPath.java
index be7778097b45b..2fa49233a4480 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPath.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPath.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent.support.filtering;
+package org.opensearch.core.xcontent.filtering;
 
 import org.opensearch.common.Glob;
 
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Filters a content path
+ *
+ * @opensearch.internal
+ */
 public class FilterPath {
 
     static final FilterPath EMPTY = new FilterPath();
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPathBasedFilter.java b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPathBasedFilter.java
similarity index 96%
rename from libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPathBasedFilter.java
rename to libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPathBasedFilter.java
index 0463caaa93118..fedfa154f33cb 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/support/filtering/FilterPathBasedFilter.java
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPathBasedFilter.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent.support.filtering;
+package org.opensearch.core.xcontent.filtering;
 
 import com.fasterxml.jackson.core.filter.TokenFilter;
 
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Concrete filter for a content path
+ *
+ * @opensearch.internal
+ */
 public class FilterPathBasedFilter extends TokenFilter {
 
     /**
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/package-info.java b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/package-info.java
new file mode 100644
index 0000000000000..934cb6499f65a
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/filtering/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base XContent Filtering Classes */
+package org.opensearch.core.xcontent.filtering;
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/package-info.java b/libs/core/src/main/java/org/opensearch/core/xcontent/package-info.java
new file mode 100644
index 0000000000000..1902e0f175456
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base XContent Core Classes */
+package org.opensearch.core.xcontent;
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/spi/MediaTypeProvider.java b/libs/core/src/main/java/org/opensearch/core/xcontent/spi/MediaTypeProvider.java
new file mode 100644
index 0000000000000..eeaadc1698df6
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/spi/MediaTypeProvider.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.xcontent.spi;
+
+import org.opensearch.core.xcontent.MediaType;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Service Provider Interface for plugins, modules, extensions providing
+ * their own Media Types
+ *
+ * @opensearch.experimental
+ * @opensearch.api
+ */
+public interface MediaTypeProvider {
+    /** Extensions that implement their own concrete {@link MediaType}s provide them through this interface method */
+    List<MediaType> getMediaTypes();
+
+    /** Extensions that implement additional {@link MediaType} aliases provide them through this interface method */
+    Map<String, MediaType> getAdditionalMediaTypes();
+}
diff --git a/libs/core/src/main/java/org/opensearch/core/xcontent/spi/package-info.java b/libs/core/src/main/java/org/opensearch/core/xcontent/spi/package-info.java
new file mode 100644
index 0000000000000..67ccd981dafa8
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/core/xcontent/spi/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Service Provider Interface for extensible media types */
+package org.opensearch.core.xcontent.spi;
diff --git a/libs/core/src/main/java/org/opensearch/package-info.java b/libs/core/src/main/java/org/opensearch/package-info.java
new file mode 100644
index 0000000000000..894660d5ad0cb
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch Core Library */
+package org.opensearch;
diff --git a/libs/core/src/main/java11/org/opensearch/common/collect/List.java b/libs/core/src/main/java11/org/opensearch/common/collect/List.java
deleted file mode 100644
index 56216d6bbafe2..0000000000000
--- a/libs/core/src/main/java11/org/opensearch/common/collect/List.java
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.Collection;
-
-public class List {
-
-    /**
-     * Delegates to the Java9 {@code List.of()} method.
-     *
-     * @param <T> the {@code List}'s element type
-     * @return an empty {@code List}
-     */
-    public static <T> java.util.List<T> of() {
-        return java.util.List.of();
-    }
-
-    /**
-     * Delegates to the Java9 {@code List.of()} method.
-     *
-     * @param <T> the {@code List}'s element type
-     * @param e1  the single element
-     * @return a {@code List} containing the specified element
-     */
-    public static <T> java.util.List<T> of(T e1) {
-        return java.util.List.of(e1);
-    }
-
-    /**
-     * Delegates to the Java9 {@code List.of()} method.
-     *
-     * @param <T> the {@code List}'s element type
-     * @param e1  the single element
-     * @return a {@code List} containing the specified element
-     */
-    public static <T> java.util.List<T> of(T e1, T e2) {
-        return java.util.List.of(e1, e2);
-    }
-
-    /**
-     * Delegates to the Java9 {@code List.of()} method.
-     *
-     * @param entries the elements to be contained in the list
-     * @param <T>     the {@code List}'s element type
-     * @return an unmodifiable list containing the specified elements.
-     */
-    @SafeVarargs
-    @SuppressWarnings("varargs")
-    public static <T> java.util.List<T> of(T... entries) {
-        return java.util.List.of(entries);
-    }
-
-    /**
-     * Delegates to the Java9 {@code List.copyOf()} method.
-     *
-     * @param <T>  the {@code List}'s element type
-     * @param coll a {@code Collection} from which elements are drawn, must be non-null
-     * @return a {@code List} containing the elements of the given {@code Collection}
-     */
-    public static <T> java.util.List<T> copyOf(Collection<? extends T> coll) {
-        return java.util.List.copyOf(coll);
-    }
-}
diff --git a/libs/core/src/main/java11/org/opensearch/common/collect/Map.java b/libs/core/src/main/java11/org/opensearch/common/collect/Map.java
deleted file mode 100644
index 21de546869390..0000000000000
--- a/libs/core/src/main/java11/org/opensearch/common/collect/Map.java
+++ /dev/null
@@ -1,194 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-public class Map {
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of() {
-        return java.util.Map.of();
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1) {
-        return java.util.Map.of(k1, v1);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2) {
-        return java.util.Map.of(k1, v1, k2, v2);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8
-    ) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8,
-        K k9,
-        V v9
-    ) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.of()} method.
-     */
-    public static <K, V> java.util.Map<K, V> of(
-        K k1,
-        V v1,
-        K k2,
-        V v2,
-        K k3,
-        V v3,
-        K k4,
-        V v4,
-        K k5,
-        V v5,
-        K k6,
-        V v6,
-        K k7,
-        V v7,
-        K k8,
-        V v8,
-        K k9,
-        V v9,
-        K k10,
-        V v10
-    ) {
-        return java.util.Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9, k10, v10);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.ofEntries()} method.
-     */
-    @SafeVarargs
-    @SuppressWarnings("varargs")
-    public static <K, V> java.util.Map<K, V> ofEntries(java.util.Map.Entry<? extends K, ? extends V>... entries) {
-        return java.util.Map.ofEntries(entries);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Map.entry()} method.
-     */
-    public static <K, V> java.util.Map.Entry<K, V> entry(K k, V v) {
-        return java.util.Map.entry(k, v);
-    }
-
-    /**
-     * Delegates to the Java10 {@code Map.copyOf()} method.
-     */
-    public static <K, V> java.util.Map<K, V> copyOf(java.util.Map<? extends K, ? extends V> map) {
-        return java.util.Map.copyOf(map);
-    }
-
-}
diff --git a/libs/core/src/main/java11/org/opensearch/common/collect/Set.java b/libs/core/src/main/java11/org/opensearch/common/collect/Set.java
deleted file mode 100644
index 0350023e4e894..0000000000000
--- a/libs/core/src/main/java11/org/opensearch/common/collect/Set.java
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.Collection;
-
-public class Set {
-
-    /**
-     * Delegates to the Java9 {@code Set.of()} method.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @return an empty {@code Set}
-     */
-    public static <T> java.util.Set<T> of() {
-        return java.util.Set.of();
-    }
-
-    /**
-     * Delegates to the Java9 {@code Set.of()} method.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @param e1  the single element
-     * @return a {@code Set} containing the specified element
-     */
-    public static <T> java.util.Set<T> of(T e1) {
-        return java.util.Set.of(e1);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Set.of()} method.
-     *
-     * @param <T> the {@code Set}'s element type
-     * @param e1 the first element
-     * @param e2 the second element
-     * @return a {@code Set} containing the specified element
-     */
-    public static <T> java.util.Set<T> of(T e1, T e2) {
-        return java.util.Set.of(e1, e2);
-    }
-
-    /**
-     * Delegates to the Java9 {@code Set.of()} method.
-     *
-     * @param entries the elements to be contained in the set
-     * @param <T>     the {@code Set}'s element type
-     * @return an unmodifiable set containing the specified elements.
-     */
-    @SafeVarargs
-    @SuppressWarnings("varargs")
-    public static <T> java.util.Set<T> of(T... entries) {
-        return java.util.Set.of(entries);
-    }
-
-    /**
-     * Delegates to the Java10 {@code Set.copyOf} method.
-     *
-     * @param <T>  the {@code Set}'s element type
-     * @param coll a {@code Collection} from which elements are drawn, must be non-null
-     * @return a {@code Set} containing the elements of the given {@code Collection}
-     */
-    public static <T> java.util.Set<T> copyOf(Collection<? extends T> coll) {
-        return java.util.Set.copyOf(coll);
-    }
-}
diff --git a/libs/core/src/main/java11/org/opensearch/core/internal/io/Streams.java b/libs/core/src/main/java11/org/opensearch/core/internal/io/Streams.java
deleted file mode 100644
index 67765392b1d46..0000000000000
--- a/libs/core/src/main/java11/org/opensearch/core/internal/io/Streams.java
+++ /dev/null
@@ -1,101 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.core.internal.io;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-
-/**
- * Simple utility methods for file and stream copying.
- * All copy methods close all affected streams when done.
- * <p>
- * Mainly for use within the framework,
- * but also useful for application code.
- */
-public abstract class Streams {
-
-    private static final ThreadLocal<byte[]> buffer = ThreadLocal.withInitial(() -> new byte[8 * 1024]);
-
-    /**
-     * Copy the contents of the given InputStream to the given OutputStream. Optionally, closes both streams when done.
-     *
-     * @param in     the stream to copy from
-     * @param out    the stream to copy to
-     * @param close  whether to close both streams after copying
-     * @param buffer buffer to use for copying
-     * @return the number of bytes copied
-     * @throws IOException in case of I/O errors
-     */
-    public static long copy(final InputStream in, final OutputStream out, byte[] buffer, boolean close) throws IOException {
-        Exception err = null;
-        try {
-            long byteCount = 0;
-            int bytesRead;
-            while ((bytesRead = in.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesRead);
-                byteCount += bytesRead;
-            }
-            out.flush();
-            return byteCount;
-        } catch (IOException | RuntimeException e) {
-            err = e;
-            throw e;
-        } finally {
-            if (close) {
-                IOUtils.close(err, in, out);
-            }
-        }
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out, boolean close) throws IOException {
-        return copy(in, out, buffer.get(), close);
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out, byte[] buffer) throws IOException {
-        return copy(in, out, buffer, true);
-    }
-
-    /**
-     * @see #copy(InputStream, OutputStream, byte[], boolean)
-     */
-    public static long copy(final InputStream in, final OutputStream out) throws IOException {
-        return copy(in, out, buffer.get(), true);
-    }
-}
diff --git a/libs/core/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider b/libs/core/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
new file mode 100644
index 0000000000000..181b802952c60
--- /dev/null
+++ b/libs/core/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
@@ -0,0 +1,9 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+
+org.opensearch.core.compress.spi.DefaultCompressorProvider
diff --git a/libs/core/src/test/java/org/opensearch/common/collect/ListTests.java b/libs/core/src/test/java/org/opensearch/common/collect/ListTests.java
deleted file mode 100644
index 70841a102b783..0000000000000
--- a/libs/core/src/test/java/org/opensearch/common/collect/ListTests.java
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.util.Arrays;
-import java.util.Collection;
-
-import static org.hamcrest.CoreMatchers.equalTo;
-
-public class ListTests extends OpenSearchTestCase {
-
-    public void testStringListOfZero() {
-        final String[] strings = {};
-        final java.util.List<String> stringsList = List.of(strings);
-        assertThat(stringsList.size(), equalTo(strings.length));
-        assertTrue(stringsList.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsList.add("foo"));
-    }
-
-    public void testStringListOfOne() {
-        final String[] strings = { "foo" };
-        final java.util.List<String> stringsList = List.of(strings);
-        assertThat(stringsList.size(), equalTo(strings.length));
-        assertTrue(stringsList.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsList.add("foo"));
-    }
-
-    public void testStringListOfTwo() {
-        final String[] strings = { "foo", "bar" };
-        final java.util.List<String> stringsList = List.of(strings);
-        assertThat(stringsList.size(), equalTo(strings.length));
-        assertTrue(stringsList.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsList.add("foo"));
-    }
-
-    public void testStringListOfN() {
-        final String[] strings = { "foo", "bar", "baz" };
-        final java.util.List<String> stringsList = List.of(strings);
-        assertThat(stringsList.size(), equalTo(strings.length));
-        assertTrue(stringsList.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsList.add("foo"));
-    }
-
-    public void testCopyOf() {
-        final Collection<String> coll = Arrays.asList("foo", "bar", "baz");
-        final java.util.List<String> copy = List.copyOf(coll);
-        assertThat(coll.size(), equalTo(copy.size()));
-        assertTrue(copy.containsAll(coll));
-        expectThrows(UnsupportedOperationException.class, () -> copy.add("foo"));
-    }
-}
diff --git a/libs/core/src/test/java/org/opensearch/common/collect/MapTests.java b/libs/core/src/test/java/org/opensearch/common/collect/MapTests.java
deleted file mode 100644
index 8d7ffa71df562..0000000000000
--- a/libs/core/src/test/java/org/opensearch/common/collect/MapTests.java
+++ /dev/null
@@ -1,210 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import org.opensearch.test.OpenSearchTestCase;
-
-import static org.hamcrest.CoreMatchers.equalTo;
-
-public class MapTests extends OpenSearchTestCase {
-
-    private static final String[] numbers = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
-
-    public void testMapOfZero() {
-        final java.util.Map<String, Integer> map = Map.of();
-        validateMapContents(map, 0);
-    }
-
-    public void testMapOfOne() {
-        final java.util.Map<String, Integer> map = Map.of(numbers[0], 0);
-        validateMapContents(map, 1);
-    }
-
-    public void testMapOfTwo() {
-        final java.util.Map<String, Integer> map = Map.of(numbers[0], 0, numbers[1], 1);
-        validateMapContents(map, 2);
-    }
-
-    public void testMapOfThree() {
-        final java.util.Map<String, Integer> map = Map.of(numbers[0], 0, numbers[1], 1, numbers[2], 2);
-        validateMapContents(map, 3);
-    }
-
-    public void testMapOfFour() {
-        final java.util.Map<String, Integer> map = Map.of(numbers[0], 0, numbers[1], 1, numbers[2], 2, numbers[3], 3);
-        validateMapContents(map, 4);
-    }
-
-    public void testMapOfFive() {
-        final java.util.Map<String, Integer> map = Map.of(numbers[0], 0, numbers[1], 1, numbers[2], 2, numbers[3], 3, numbers[4], 4);
-        validateMapContents(map, 5);
-    }
-
-    public void testMapOfSix() {
-        final java.util.Map<String, Integer> map = Map.of(
-            numbers[0],
-            0,
-            numbers[1],
-            1,
-            numbers[2],
-            2,
-            numbers[3],
-            3,
-            numbers[4],
-            4,
-            numbers[5],
-            5
-        );
-        validateMapContents(map, 6);
-    }
-
-    public void testMapOfSeven() {
-        final java.util.Map<String, Integer> map = Map.of(
-            numbers[0],
-            0,
-            numbers[1],
-            1,
-            numbers[2],
-            2,
-            numbers[3],
-            3,
-            numbers[4],
-            4,
-            numbers[5],
-            5,
-            numbers[6],
-            6
-        );
-        validateMapContents(map, 7);
-    }
-
-    public void testMapOfEight() {
-        final java.util.Map<String, Integer> map = Map.of(
-            numbers[0],
-            0,
-            numbers[1],
-            1,
-            numbers[2],
-            2,
-            numbers[3],
-            3,
-            numbers[4],
-            4,
-            numbers[5],
-            5,
-            numbers[6],
-            6,
-            numbers[7],
-            7
-        );
-        validateMapContents(map, 8);
-    }
-
-    public void testMapOfNine() {
-        final java.util.Map<String, Integer> map = Map.of(
-            numbers[0],
-            0,
-            numbers[1],
-            1,
-            numbers[2],
-            2,
-            numbers[3],
-            3,
-            numbers[4],
-            4,
-            numbers[5],
-            5,
-            numbers[6],
-            6,
-            numbers[7],
-            7,
-            numbers[8],
-            8
-        );
-        validateMapContents(map, 9);
-    }
-
-    public void testMapOfTen() {
-        final java.util.Map<String, Integer> map = Map.of(
-            numbers[0],
-            0,
-            numbers[1],
-            1,
-            numbers[2],
-            2,
-            numbers[3],
-            3,
-            numbers[4],
-            4,
-            numbers[5],
-            5,
-            numbers[6],
-            6,
-            numbers[7],
-            7,
-            numbers[8],
-            8,
-            numbers[9],
-            9
-        );
-        validateMapContents(map, 10);
-    }
-
-    private static void validateMapContents(java.util.Map<String, Integer> map, int size) {
-        assertThat(map.size(), equalTo(size));
-        for (int k = 0; k < map.size(); k++) {
-            assertEquals(Integer.class, map.get(numbers[k]).getClass());
-            assertThat(k, equalTo(map.get(numbers[k])));
-        }
-        expectThrows(UnsupportedOperationException.class, () -> map.put("foo", 42));
-    }
-
-    public void testOfEntries() {
-        final java.util.Map<String, Integer> map = Map.ofEntries(
-            Map.entry(numbers[0], 0),
-            Map.entry(numbers[1], 1),
-            Map.entry(numbers[2], 2)
-        );
-        validateMapContents(map, 3);
-    }
-
-    public void testCopyOf() {
-        final java.util.Map<String, String> map1 = Map.of("fooK", "fooV", "barK", "barV", "bazK", "bazV");
-        final java.util.Map<String, String> copy = Map.copyOf(map1);
-        assertThat(map1.size(), equalTo(copy.size()));
-        for (java.util.Map.Entry<String, String> entry : map1.entrySet()) {
-            assertEquals(entry.getValue(), copy.get(entry.getKey()));
-        }
-        expectThrows(UnsupportedOperationException.class, () -> copy.put("foo", "bar"));
-    }
-}
diff --git a/libs/core/src/test/java/org/opensearch/common/collect/SetTests.java b/libs/core/src/test/java/org/opensearch/common/collect/SetTests.java
deleted file mode 100644
index 1b7f29ff0d6f1..0000000000000
--- a/libs/core/src/test/java/org/opensearch/common/collect/SetTests.java
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.util.Arrays;
-import java.util.Collection;
-
-import static org.hamcrest.CoreMatchers.equalTo;
-
-public class SetTests extends OpenSearchTestCase {
-
-    public void testStringSetOfZero() {
-        final String[] strings = {};
-        final java.util.Set<String> stringsSet = Set.of(strings);
-        assertThat(stringsSet.size(), equalTo(strings.length));
-        assertTrue(stringsSet.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsSet.add("foo"));
-    }
-
-    public void testStringSetOfOne() {
-        final String[] strings = { "foo" };
-        final java.util.Set<String> stringsSet = Set.of(strings);
-        assertThat(stringsSet.size(), equalTo(strings.length));
-        assertTrue(stringsSet.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsSet.add("foo"));
-    }
-
-    public void testStringSetOfTwo() {
-        final String[] strings = { "foo", "bar" };
-        final java.util.Set<String> stringsSet = Set.of(strings);
-        assertThat(stringsSet.size(), equalTo(strings.length));
-        assertTrue(stringsSet.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsSet.add("foo"));
-    }
-
-    public void testStringSetOfN() {
-        final String[] strings = { "foo", "bar", "baz" };
-        final java.util.Set<String> stringsSet = Set.of(strings);
-        assertThat(stringsSet.size(), equalTo(strings.length));
-        assertTrue(stringsSet.containsAll(Arrays.asList(strings)));
-        expectThrows(UnsupportedOperationException.class, () -> stringsSet.add("foo"));
-    }
-
-    public void testCopyOf() {
-        final Collection<String> coll = Arrays.asList("foo", "bar", "baz");
-        final java.util.Set<String> copy = Set.copyOf(coll);
-        assertThat(coll.size(), equalTo(copy.size()));
-        assertTrue(copy.containsAll(coll));
-        expectThrows(UnsupportedOperationException.class, () -> copy.add("foo"));
-    }
-}
diff --git a/server/src/test/java/org/opensearch/action/ActionListenerTests.java b/libs/core/src/test/java/org/opensearch/core/action/ActionListenerTests.java
similarity index 98%
rename from server/src/test/java/org/opensearch/action/ActionListenerTests.java
rename to libs/core/src/test/java/org/opensearch/core/action/ActionListenerTests.java
index bf64b4ed8a1a5..8d2bef3db68ea 100644
--- a/server/src/test/java/org/opensearch/action/ActionListenerTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/action/ActionListenerTests.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.CheckedConsumer;
@@ -266,10 +266,9 @@ public void onFailure(Exception e) {
         assertThat(assertionError.getCause(), instanceOf(IllegalArgumentException.class));
         assertNull(exReference.get());
 
-        assertionError = expectThrows(
-            AssertionError.class,
-            () -> ActionListener.completeWith(listener, () -> { throw new IllegalArgumentException(); })
-        );
+        assertionError = expectThrows(AssertionError.class, () -> ActionListener.completeWith(listener, () -> {
+            throw new IllegalArgumentException();
+        }));
         assertThat(assertionError.getCause(), instanceOf(IllegalArgumentException.class));
         assertThat(exReference.get(), instanceOf(IllegalArgumentException.class));
     }
diff --git a/server/src/test/java/org/opensearch/action/NotifyOnceListenerTests.java b/libs/core/src/test/java/org/opensearch/core/action/NotifyOnceListenerTests.java
similarity index 98%
rename from server/src/test/java/org/opensearch/action/NotifyOnceListenerTests.java
rename to libs/core/src/test/java/org/opensearch/core/action/NotifyOnceListenerTests.java
index 79593f85c2890..948cd752a27c3 100644
--- a/server/src/test/java/org/opensearch/action/NotifyOnceListenerTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/action/NotifyOnceListenerTests.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action;
+package org.opensearch.core.action;
 
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/support/DefaultShardOperationFailedExceptionTests.java b/libs/core/src/test/java/org/opensearch/core/action/support/DefaultShardOperationFailedExceptionTests.java
similarity index 91%
rename from server/src/test/java/org/opensearch/action/support/DefaultShardOperationFailedExceptionTests.java
rename to libs/core/src/test/java/org/opensearch/core/action/support/DefaultShardOperationFailedExceptionTests.java
index 40a5b05b1dbc6..ad52f2dc12b8f 100644
--- a/server/src/test/java/org/opensearch/action/support/DefaultShardOperationFailedExceptionTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/action/support/DefaultShardOperationFailedExceptionTests.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action.support;
+package org.opensearch.core.action.support;
 
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
@@ -39,18 +39,19 @@
 import org.apache.lucene.store.LockObtainFailedException;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.EOFException;
@@ -92,7 +93,7 @@ public void testToXContent() throws IOException {
             assertEquals(
                 "{\"shard\":-1,\"index\":null,\"status\":\"INTERNAL_SERVER_ERROR\","
                     + "\"reason\":{\"type\":\"exception\",\"reason\":\"foo\"}}",
-                Strings.toString(exception)
+                Strings.toString(MediaTypeRegistry.JSON, exception)
             );
         }
         {
@@ -102,7 +103,7 @@ public void testToXContent() throws IOException {
             assertEquals(
                 "{\"shard\":-1,\"index\":null,\"status\":\"INTERNAL_SERVER_ERROR\",\"reason\":{\"type\":\"exception\","
                     + "\"reason\":\"foo\",\"caused_by\":{\"type\":\"illegal_argument_exception\",\"reason\":\"bar\"}}}",
-                Strings.toString(exception)
+                Strings.toString(MediaTypeRegistry.JSON, exception)
             );
         }
         {
@@ -112,7 +113,7 @@ public void testToXContent() throws IOException {
             assertEquals(
                 "{\"shard\":2,\"index\":\"test\",\"status\":\"INTERNAL_SERVER_ERROR\","
                     + "\"reason\":{\"type\":\"illegal_state_exception\",\"reason\":\"bar\"}}",
-                Strings.toString(exception)
+                Strings.toString(MediaTypeRegistry.JSON, exception)
             );
         }
         {
@@ -124,7 +125,7 @@ public void testToXContent() throws IOException {
             assertEquals(
                 "{\"shard\":1,\"index\":\"test\",\"status\":\"BAD_REQUEST\","
                     + "\"reason\":{\"type\":\"illegal_argument_exception\",\"reason\":\"foo\"}}",
-                Strings.toString(exception)
+                Strings.toString(MediaTypeRegistry.JSON, exception)
             );
         }
     }
diff --git a/server/src/test/java/org/opensearch/common/StringsTests.java b/libs/core/src/test/java/org/opensearch/core/common/StringsTests.java
similarity index 77%
rename from server/src/test/java/org/opensearch/common/StringsTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/StringsTests.java
index 7d87fc33c12e7..b79bb6fc89f9e 100644
--- a/server/src/test/java/org/opensearch/common/StringsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/StringsTests.java
@@ -6,35 +6,12 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common;
+package org.opensearch.core.common;
 
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
@@ -42,8 +19,8 @@
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
 
+/** tests for Strings utility class */
 public class StringsTests extends OpenSearchTestCase {
-
     public void testIsAllOrWildCardString() {
         assertThat(Strings.isAllOrWildcard("_all"), is(true));
         assertThat(Strings.isAllOrWildcard("*"), is(true));
@@ -76,8 +53,21 @@ public void testCleanTruncate() {
          * circle around it with a slash through it. As in "no 'o's allowed
          * here.
          */
-        assertEquals("o", Strings.cleanTruncate("o\uD83D\uDEAB", 1));
-        assertEquals("", Strings.cleanTruncate("foo", 0));
+        assertEquals("o", org.opensearch.core.common.Strings.cleanTruncate("o\uD83D\uDEAB", 1));
+        assertEquals("", org.opensearch.core.common.Strings.cleanTruncate("foo", 0));
+    }
+
+    public void testSplitStringToSet() {
+        assertEquals(Strings.tokenizeByCommaToSet(null), Sets.newHashSet());
+        assertEquals(Strings.tokenizeByCommaToSet(""), Sets.newHashSet());
+        assertEquals(Strings.tokenizeByCommaToSet("a,b,c"), Sets.newHashSet("a", "b", "c"));
+        assertEquals(Strings.tokenizeByCommaToSet("a, b, c"), Sets.newHashSet("a", "b", "c"));
+        assertEquals(Strings.tokenizeByCommaToSet(" a ,  b, c  "), Sets.newHashSet("a", "b", "c"));
+        assertEquals(Strings.tokenizeByCommaToSet("aa, bb, cc"), Sets.newHashSet("aa", "bb", "cc"));
+        assertEquals(Strings.tokenizeByCommaToSet(" a "), Sets.newHashSet("a"));
+        assertEquals(Strings.tokenizeByCommaToSet("   a   "), Sets.newHashSet("a"));
+        assertEquals(Strings.tokenizeByCommaToSet("   aa   "), Sets.newHashSet("aa"));
+        assertEquals(Strings.tokenizeByCommaToSet("   "), Sets.newHashSet());
     }
 
     public void testToStringToXContent() {
@@ -104,7 +94,7 @@ public void testToStringToXContent() {
             }
         }
 
-        String toString = Strings.toString(toXContent);
+        String toString = Strings.toString(MediaTypeRegistry.JSON, toXContent);
         if (error) {
             assertThat(toString, containsString("\"error\":\"error building toString out of XContent:"));
             assertThat(toString, containsString("\"stack_trace\":"));
@@ -117,24 +107,11 @@ public void testToStringToXContent() {
     public void testToStringToXContentWithOrWithoutParams() {
         ToXContent toXContent = (builder, params) -> builder.field("color_from_param", params.param("color", "red"));
         // Rely on the default value of "color" param when params are not passed
-        assertThat(Strings.toString(toXContent), containsString("\"color_from_param\":\"red\""));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, toXContent), containsString("\"color_from_param\":\"red\""));
         // Pass "color" param explicitly
         assertThat(
-            Strings.toString(toXContent, new ToXContent.MapParams(Collections.singletonMap("color", "blue"))),
+            Strings.toString(MediaTypeRegistry.JSON, toXContent, new ToXContent.MapParams(Collections.singletonMap("color", "blue"))),
             containsString("\"color_from_param\":\"blue\"")
         );
     }
-
-    public void testSplitStringToSet() {
-        assertEquals(Strings.tokenizeByCommaToSet(null), Sets.newHashSet());
-        assertEquals(Strings.tokenizeByCommaToSet(""), Sets.newHashSet());
-        assertEquals(Strings.tokenizeByCommaToSet("a,b,c"), Sets.newHashSet("a", "b", "c"));
-        assertEquals(Strings.tokenizeByCommaToSet("a, b, c"), Sets.newHashSet("a", "b", "c"));
-        assertEquals(Strings.tokenizeByCommaToSet(" a ,  b, c  "), Sets.newHashSet("a", "b", "c"));
-        assertEquals(Strings.tokenizeByCommaToSet("aa, bb, cc"), Sets.newHashSet("aa", "bb", "cc"));
-        assertEquals(Strings.tokenizeByCommaToSet(" a "), Sets.newHashSet("a"));
-        assertEquals(Strings.tokenizeByCommaToSet("   a   "), Sets.newHashSet("a"));
-        assertEquals(Strings.tokenizeByCommaToSet("   aa   "), Sets.newHashSet("aa"));
-        assertEquals(Strings.tokenizeByCommaToSet("   "), Sets.newHashSet());
-    }
 }
diff --git a/server/src/test/java/org/opensearch/common/io/StreamsTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/StreamsTests.java
similarity index 92%
rename from server/src/test/java/org/opensearch/common/io/StreamsTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/StreamsTests.java
index f28d1b1762ca2..f2f46daa0fab3 100644
--- a/server/src/test/java/org/opensearch/common/io/StreamsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/StreamsTests.java
@@ -30,11 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io;
+package org.opensearch.core.common.io;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.io.Streams;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayOutputStream;
@@ -104,7 +105,7 @@ public void testLimitInputStream() throws IOException {
         final int limit = randomIntBetween(0, bytes.length);
         final BytesArray stuffArray = new BytesArray(bytes);
         final ByteArrayOutputStream out = new ByteArrayOutputStream(bytes.length);
-        final long count = org.opensearch.core.internal.io.Streams.copy(Streams.limitStream(stuffArray.streamInput(), limit), out);
+        final long count = org.opensearch.common.util.io.Streams.copy(Streams.limitStream(stuffArray.streamInput(), limit), out);
         assertEquals(limit, count);
         assertThat(Arrays.equals(out.toByteArray(), Arrays.copyOf(bytes, limit)), equalTo(true));
     }
diff --git a/server/src/test/java/org/opensearch/common/io/stream/BaseStreamTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BaseStreamTests.java
similarity index 95%
rename from server/src/test/java/org/opensearch/common/io/stream/BaseStreamTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/BaseStreamTests.java
index b92e59e43e0db..5da8f58f688a5 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/BaseStreamTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BaseStreamTests.java
@@ -30,22 +30,25 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.settings.SecureString;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.script.JodaCompatibleZonedDateTime;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
 import java.io.EOFException;
 import java.io.IOException;
 import java.time.Instant;
+import java.time.ZoneOffset;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -186,6 +189,7 @@ public void testLinkedHashMap() throws IOException {
         }
         BytesStreamOutput out = new BytesStreamOutput();
         out.writeGenericValue(write);
+        @SuppressWarnings("unchecked")
         LinkedHashMap<String, Integer> read = (LinkedHashMap<String, Integer>) getStreamInput(out.bytes()).readGenericValue();
         assertEquals(size, read.size());
         int index = 0;
@@ -396,6 +400,18 @@ public void testOptionalInstantSerialization() throws IOException {
         }
     }
 
+    public void testJodaDateTimeSerialization() throws IOException {
+        final BytesStreamOutput output = new BytesStreamOutput();
+        long millis = randomIntBetween(0, Integer.MAX_VALUE);
+        JodaCompatibleZonedDateTime time = new JodaCompatibleZonedDateTime(Instant.ofEpochMilli(millis), ZoneOffset.ofHours(-7));
+        output.writeGenericValue(time);
+
+        final BytesReference bytesReference = output.bytes();
+        final StreamInput input = getStreamInput(bytesReference);
+        Object inTime = input.readGenericValue();
+        assertEquals(time, inTime);
+    }
+
     static final class WriteableString implements Writeable {
         final String string;
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/ByteBufferStreamInputTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/ByteBufferStreamInputTests.java
similarity index 87%
rename from server/src/test/java/org/opensearch/common/io/stream/ByteBufferStreamInputTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/ByteBufferStreamInputTests.java
index 1061b335d715a..d50160b2b3e2d 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/ByteBufferStreamInputTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/ByteBufferStreamInputTests.java
@@ -6,10 +6,10 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
diff --git a/server/src/test/java/org/opensearch/common/io/stream/BytesReferenceStreamInputTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesReferenceStreamInputTests.java
similarity index 83%
rename from server/src/test/java/org/opensearch/common/io/stream/BytesReferenceStreamInputTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesReferenceStreamInputTests.java
index ed77c3130a32d..7eca07d9b63d5 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/BytesReferenceStreamInputTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesReferenceStreamInputTests.java
@@ -6,9 +6,9 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/BytesStreamInputTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesStreamInputTests.java
similarity index 86%
rename from server/src/test/java/org/opensearch/common/io/stream/BytesStreamInputTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesStreamInputTests.java
index c7a47e7580b02..d61eea75538b3 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/BytesStreamInputTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/BytesStreamInputTests.java
@@ -6,10 +6,10 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/FilterStreamInputTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/FilterStreamInputTests.java
similarity index 86%
rename from server/src/test/java/org/opensearch/common/io/stream/FilterStreamInputTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/FilterStreamInputTests.java
index 3cf9dc656a8f1..a044586e095e3 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/FilterStreamInputTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/FilterStreamInputTests.java
@@ -6,10 +6,10 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/InputStreamStreamInputTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/InputStreamStreamInputTests.java
similarity index 86%
rename from server/src/test/java/org/opensearch/common/io/stream/InputStreamStreamInputTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/InputStreamStreamInputTests.java
index 6a31c21445a04..4bcd697b1c283 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/InputStreamStreamInputTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/InputStreamStreamInputTests.java
@@ -6,10 +6,10 @@
  * compatible open source license.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/NamedWriteableRegistryTests.java b/libs/core/src/test/java/org/opensearch/core/common/io/stream/NamedWriteableRegistryTests.java
similarity index 98%
rename from server/src/test/java/org/opensearch/common/io/stream/NamedWriteableRegistryTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/io/stream/NamedWriteableRegistryTests.java
index e1c0177435005..96f2b93524067 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/NamedWriteableRegistryTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/io/stream/NamedWriteableRegistryTests.java
@@ -30,14 +30,14 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io.stream;
+package org.opensearch.core.common.io.stream;
+
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 
-import org.opensearch.test.OpenSearchTestCase;
-
 public class NamedWriteableRegistryTests extends OpenSearchTestCase {
 
     private static class DummyNamedWriteable implements NamedWriteable {
diff --git a/server/src/test/java/org/opensearch/common/unit/ByteSizeUnitTests.java b/libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeUnitTests.java
similarity index 90%
rename from server/src/test/java/org/opensearch/common/unit/ByteSizeUnitTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeUnitTests.java
index 2435fc465a83b..07b9131602ac3 100644
--- a/server/src/test/java/org/opensearch/common/unit/ByteSizeUnitTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeUnitTests.java
@@ -30,20 +30,20 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.unit;
+package org.opensearch.core.common.unit;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
-import static org.opensearch.common.unit.ByteSizeUnit.BYTES;
-import static org.opensearch.common.unit.ByteSizeUnit.GB;
-import static org.opensearch.common.unit.ByteSizeUnit.KB;
-import static org.opensearch.common.unit.ByteSizeUnit.MB;
-import static org.opensearch.common.unit.ByteSizeUnit.PB;
-import static org.opensearch.common.unit.ByteSizeUnit.TB;
+import static org.opensearch.core.common.unit.ByteSizeUnit.BYTES;
+import static org.opensearch.core.common.unit.ByteSizeUnit.GB;
+import static org.opensearch.core.common.unit.ByteSizeUnit.KB;
+import static org.opensearch.core.common.unit.ByteSizeUnit.MB;
+import static org.opensearch.core.common.unit.ByteSizeUnit.PB;
+import static org.opensearch.core.common.unit.ByteSizeUnit.TB;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
diff --git a/server/src/test/java/org/opensearch/common/unit/ByteSizeValueTests.java b/libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeValueTests.java
similarity index 97%
rename from server/src/test/java/org/opensearch/common/unit/ByteSizeValueTests.java
rename to libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeValueTests.java
index 7512bf2b32e24..def1694a72ba4 100644
--- a/server/src/test/java/org/opensearch/common/unit/ByteSizeValueTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/common/unit/ByteSizeValueTests.java
@@ -30,10 +30,10 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.unit;
+package org.opensearch.core.common.unit;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.hamcrest.MatcherAssert;
 
@@ -336,12 +336,10 @@ public void testParseInvalidNumber() throws IOException {
     public void testParseFractionalNumber() throws IOException {
         ByteSizeUnit unit = randomValueOtherThan(ByteSizeUnit.BYTES, () -> randomFrom(ByteSizeUnit.values()));
         String fractionalValue = "23.5" + unit.getSuffix();
-        ByteSizeValue instance = ByteSizeValue.parseBytesSizeValue(fractionalValue, "test");
-        assertEquals(fractionalValue, instance.toString());
-        assertWarnings(
-            "Fractional bytes values are deprecated. Use non-fractional bytes values instead: ["
-                + fractionalValue
-                + "] found for setting [test]"
+        // test exception is thrown: fractional byte size values has been deprecated since Legacy 6.2
+        OpenSearchParseException e = expectThrows(
+            OpenSearchParseException.class,
+            () -> ByteSizeValue.parseBytesSizeValue(fractionalValue, "test")
         );
     }
 
diff --git a/libs/core/src/test/java/org/opensearch/core/internal/io/IOUtilsTests.java b/libs/core/src/test/java/org/opensearch/core/internal/io/IOUtilsTests.java
index f1c8642b73044..cd7a40b655579 100644
--- a/libs/core/src/test/java/org/opensearch/core/internal/io/IOUtilsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/internal/io/IOUtilsTests.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.util.Constants;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.io.PathUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.net.URI;
 import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.AccessDeniedException;
@@ -172,10 +172,8 @@ public void runTestRm(final boolean exception) throws IOException {
         for (int i = 0; i < numberOfLocations; i++) {
             if (exception && randomBoolean()) {
                 final Path location = createTempDir();
-                final FileSystem fs = new AccessDeniedWhileDeletingFileSystem(location.getFileSystem()).getFileSystem(
-                    URI.create("file:///")
-                );
-                final Path wrapped = new FilterPath(location, fs);
+                final FilterFileSystemProvider ffsp = new AccessDeniedWhileDeletingFileSystem(location.getFileSystem());
+                final Path wrapped = ffsp.wrapPath(location);
                 locations[i] = wrapped.resolve(randomAlphaOfLength(8));
                 Files.createDirectory(locations[i]);
                 locationsThrowingException.add(locations[i]);
@@ -256,8 +254,8 @@ public FileChannel newFileChannel(final Path path, final Set<? extends OpenOptio
 
     public void testFsyncAccessDeniedOpeningDirectory() throws Exception {
         final Path path = createTempDir().toRealPath();
-        final FileSystem fs = new AccessDeniedWhileOpeningDirectoryFileSystem(path.getFileSystem()).getFileSystem(URI.create("file:///"));
-        final Path wrapped = new FilterPath(path, fs);
+        final FilterFileSystemProvider ffsp = new AccessDeniedWhileOpeningDirectoryFileSystem(path.getFileSystem());
+        final Path wrapped = ffsp.wrapPath(path);
         if (Constants.WINDOWS) {
             // no exception, we early return and do not even try to open the directory
             IOUtils.fsync(wrapped, true);
diff --git a/libs/core/src/test/java/org/opensearch/core/internal/io/StreamsTests.java b/libs/core/src/test/java/org/opensearch/core/internal/io/StreamsTests.java
index b489a9a018ae5..2ba18221cbe4f 100644
--- a/libs/core/src/test/java/org/opensearch/core/internal/io/StreamsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/internal/io/StreamsTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.core.internal.io;
 
+import org.opensearch.common.util.io.Streams;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
diff --git a/libs/core/src/test/java/org/opensearch/core/internal/net/NetUtilsTests.java b/libs/core/src/test/java/org/opensearch/core/internal/net/NetUtilsTests.java
index 91236b4f8fb84..c9b9b7c9918ea 100644
--- a/libs/core/src/test/java/org/opensearch/core/internal/net/NetUtilsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/internal/net/NetUtilsTests.java
@@ -33,15 +33,17 @@
 package org.opensearch.core.internal.net;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.bootstrap.JavaVersion;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.common.util.net.NetUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.lang.Runtime.Version;
+
 public class NetUtilsTests extends OpenSearchTestCase {
 
     public void testExtendedSocketOptions() {
         assumeTrue("JDK possibly not supported", Constants.JVM_NAME.contains("HotSpot") || Constants.JVM_NAME.contains("OpenJDK"));
-        assumeTrue("JDK version not supported", JavaVersion.current().compareTo(JavaVersion.parse("11")) >= 0);
+        assumeTrue("JDK version not supported", Runtime.version().compareTo(Version.parse("11")) >= 0);
         assumeTrue("Platform possibly not supported", IOUtils.LINUX || IOUtils.MAC_OS_X);
         assertNotNull(NetUtils.getTcpKeepIdleSocketOptionOrNull());
         assertNotNull(NetUtils.getTcpKeepIntervalSocketOptionOrNull());
diff --git a/libs/core/src/test/java/org/opensearch/core/util/BytesRefUtilsTests.java b/libs/core/src/test/java/org/opensearch/core/util/BytesRefUtilsTests.java
new file mode 100644
index 0000000000000..421263b883f2a
--- /dev/null
+++ b/libs/core/src/test/java/org/opensearch/core/util/BytesRefUtilsTests.java
@@ -0,0 +1,97 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.util;
+
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.BytesRefArray;
+import org.apache.lucene.util.BytesRefBuilder;
+import org.apache.lucene.util.Counter;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+/**
+ * Tests for the {@link BytesRefUtils} class
+ */
+public class BytesRefUtilsTests extends OpenSearchTestCase {
+    public void testSortAndDedupByteRefArray() {
+        SortedSet<BytesRef> set = new TreeSet<>();
+        final int numValues = scaledRandomIntBetween(0, 10000);
+        List<BytesRef> tmpList = new ArrayList<>();
+        BytesRefArray array = new BytesRefArray(Counter.newCounter());
+        for (int i = 0; i < numValues; i++) {
+            String s = randomRealisticUnicodeOfCodepointLengthBetween(1, 100);
+            set.add(new BytesRef(s));
+            tmpList.add(new BytesRef(s));
+            array.append(new BytesRef(s));
+        }
+        if (randomBoolean()) {
+            Collections.shuffle(tmpList, random());
+            for (BytesRef ref : tmpList) {
+                array.append(ref);
+            }
+        }
+        int[] indices = new int[array.size()];
+        for (int i = 0; i < indices.length; i++) {
+            indices[i] = i;
+        }
+        int numUnique = BytesRefUtils.sortAndDedup(array, indices);
+        assertThat(numUnique, equalTo(set.size()));
+        Iterator<BytesRef> iterator = set.iterator();
+
+        BytesRefBuilder spare = new BytesRefBuilder();
+        for (int i = 0; i < numUnique; i++) {
+            assertThat(iterator.hasNext(), is(true));
+            assertThat(array.get(spare, indices[i]), equalTo(iterator.next()));
+        }
+    }
+
+    public void testSortByteRefArray() {
+        List<BytesRef> values = new ArrayList<>();
+        final int numValues = scaledRandomIntBetween(0, 10000);
+        BytesRefArray array = new BytesRefArray(Counter.newCounter());
+        for (int i = 0; i < numValues; i++) {
+            String s = randomRealisticUnicodeOfCodepointLengthBetween(1, 100);
+            values.add(new BytesRef(s));
+            array.append(new BytesRef(s));
+        }
+        if (randomBoolean()) {
+            Collections.shuffle(values, random());
+        }
+        int[] indices = new int[array.size()];
+        for (int i = 0; i < indices.length; i++) {
+            indices[i] = i;
+        }
+        BytesRefUtils.sort(array, indices);
+        Collections.sort(values);
+        Iterator<BytesRef> iterator = values.iterator();
+
+        BytesRefBuilder spare = new BytesRefBuilder();
+        for (int i = 0; i < values.size(); i++) {
+            assertThat(iterator.hasNext(), is(true));
+            assertThat(array.get(spare, indices[i]), equalTo(iterator.next()));
+        }
+    }
+
+    public void testBytesToLong() {
+        final long value = randomLong();
+        final BytesReference buffer = BytesReference.fromByteBuffer(ByteBuffer.allocate(8).putLong(value).flip());
+        assertThat(BytesRefUtils.bytesToLong(buffer.toBytesRef()), equalTo(value));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/io/FileSystemUtilsTests.java b/libs/core/src/test/java/org/opensearch/core/util/FileSystemUtilsTests.java
similarity index 98%
rename from server/src/test/java/org/opensearch/common/io/FileSystemUtilsTests.java
rename to libs/core/src/test/java/org/opensearch/core/util/FileSystemUtilsTests.java
index bb0a1c486a30c..8b29378dfde12 100644
--- a/server/src/test/java/org/opensearch/common/io/FileSystemUtilsTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/util/FileSystemUtilsTests.java
@@ -30,10 +30,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.io;
+package org.opensearch.core.util;
 
-import org.apache.lucene.util.Constants;
 import org.apache.lucene.tests.util.LuceneTestCase.SuppressFileSystems;
+import org.apache.lucene.util.Constants;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathTests.java b/libs/core/src/test/java/org/opensearch/core/xcontent/filtering/FilterPathTests.java
similarity index 99%
rename from server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathTests.java
rename to libs/core/src/test/java/org/opensearch/core/xcontent/filtering/FilterPathTests.java
index b96d6904d20aa..0c5a17b70a956 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathTests.java
+++ b/libs/core/src/test/java/org/opensearch/core/xcontent/filtering/FilterPathTests.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.common.xcontent.support.filtering;
+package org.opensearch.core.xcontent.filtering;
 
 import org.opensearch.common.util.set.Sets;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/libs/dissect/build.gradle b/libs/dissect/build.gradle
index 0f0b8407e7e6b..dc98d2820ef52 100644
--- a/libs/dissect/build.gradle
+++ b/libs/dissect/build.gradle
@@ -34,10 +34,9 @@ dependencies {
   }
   testImplementation "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
   testImplementation "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
-  testImplementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  testImplementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
 }
 
 tasks.named('forbiddenApisMain').configure {
   replaceSignatureFiles 'jdk-signatures'
 }
-
diff --git a/libs/dissect/src/test/java/org/opensearch/dissect/DissectParserTests.java b/libs/dissect/src/test/java/org/opensearch/dissect/DissectParserTests.java
index fcd0dc8e248aa..665fe63e31b1d 100644
--- a/libs/dissect/src/test/java/org/opensearch/dissect/DissectParserTests.java
+++ b/libs/dissect/src/test/java/org/opensearch/dissect/DissectParserTests.java
@@ -34,10 +34,10 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.Matchers;
-import org.mockito.internal.util.collections.Sets;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -45,6 +45,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.mockito.internal.util.collections.Sets;
+
 import static com.carrotsearch.randomizedtesting.RandomizedTest.randomAsciiAlphanumOfLengthBetween;
 
 public class DissectParserTests extends OpenSearchTestCase {
diff --git a/libs/dissect/src/test/resources/specification/tests.json b/libs/dissect/src/test/resources/specification/tests.json
index 1cb85ce651940..490383ba3fedb 100644
--- a/libs/dissect/src/test/resources/specification/tests.json
+++ b/libs/dissect/src/test/resources/specification/tests.json
@@ -360,4 +360,4 @@
     "append": ""
   }
 
-]
\ No newline at end of file
+]
diff --git a/libs/geo/build.gradle b/libs/geo/build.gradle
index fac5c1b84d2b0..8b81129f43b67 100644
--- a/libs/geo/build.gradle
+++ b/libs/geo/build.gradle
@@ -42,4 +42,3 @@ tasks.named('forbiddenApisMain').configure {
   // TODO: Need to decide how we want to handle for forbidden signatures with the changes to core
   replaceSignatureFiles 'jdk-signatures'
 }
-
diff --git a/libs/geo/src/main/java/org/opensearch/geometry/Circle.java b/libs/geo/src/main/java/org/opensearch/geometry/Circle.java
index 6f8b0dc6929cc..cf1dce8966e1f 100644
--- a/libs/geo/src/main/java/org/opensearch/geometry/Circle.java
+++ b/libs/geo/src/main/java/org/opensearch/geometry/Circle.java
@@ -39,12 +39,19 @@
  * and optional altitude in meters.
  */
 public class Circle implements Geometry {
+
+    /** Empty circle : x=0, y=0, z=NaN radius=-1 */
     public static final Circle EMPTY = new Circle();
+    /** Latitude of the center of the circle in degrees */
     private final double y;
+    /** Longitude of the center of the circle in degrees */
     private final double x;
+    /** Altitude of the center of the circle in meters (NaN if irrelevant) */
     private final double z;
+    /** Radius of the circle in meters */
     private final double radiusMeters;
 
+    /** Create an {@link #EMPTY} circle */
     private Circle() {
         y = 0;
         x = 0;
@@ -52,10 +59,23 @@ private Circle() {
         radiusMeters = -1;
     }
 
+    /**
+     * Create a circle with no altitude.
+     * @param x Longitude of the center of the circle in degrees
+     * @param y Latitude of the center of the circle in degrees
+     * @param radiusMeters Radius of the circle in meters
+     */
     public Circle(final double x, final double y, final double radiusMeters) {
         this(x, y, Double.NaN, radiusMeters);
     }
 
+    /**
+     * Create a circle with altitude.
+     * @param x Longitude of the center of the circle in degrees
+     * @param y Latitude of the center of the circle in degrees
+     * @param z Altitude of the center of the circle in meters
+     * @param radiusMeters Radius of the circle in meters
+     */
     public Circle(final double x, final double y, final double z, final double radiusMeters) {
         this.y = y;
         this.x = x;
@@ -66,39 +86,68 @@ public Circle(final double x, final double y, final double z, final double radiu
         }
     }
 
+    /**
+     * @return The type of this geometry (always {@link ShapeType#CIRCLE})
+     */
     @Override
     public ShapeType type() {
         return ShapeType.CIRCLE;
     }
 
+    /**
+     * @return The y (latitude) of the center of the circle in degrees
+     */
     public double getY() {
         return y;
     }
 
+    /**
+     * @return The x (longitude) of the center of the circle in degrees
+     */
     public double getX() {
         return x;
     }
 
+    /**
+     * @return The radius of the circle in meters
+     */
     public double getRadiusMeters() {
         return radiusMeters;
     }
 
+    /**
+     * @return The altitude of the center of the circle in meters (NaN if irrelevant)
+     */
     public double getZ() {
         return z;
     }
 
+    /**
+     * @return The latitude (y) of the center of the circle in degrees
+     */
     public double getLat() {
         return y;
     }
 
+    /**
+     * @return The longitude (x) of the center of the circle in degrees
+     */
     public double getLon() {
         return x;
     }
 
+    /**
+     * @return The altitude (z) of the center of the circle in meters (NaN if irrelevant)
+     */
     public double getAlt() {
         return z;
     }
 
+    /**
+     * Compare this circle to another circle.
+     * @param o The other circle
+     * @return True if the two circles are equal in all their properties. False if null or different.
+     */
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
@@ -111,6 +160,9 @@ public boolean equals(Object o) {
         return (Double.compare(circle.z, z) == 0);
     }
 
+    /**
+     * @return The hashcode of this circle.
+     */
     @Override
     public int hashCode() {
         int result;
@@ -126,11 +178,22 @@ public int hashCode() {
         return result;
     }
 
+    /**
+     * Visit this circle with a {@link GeometryVisitor}.
+     * @param visitor The visitor
+     * @param <T> The return type of the visitor
+     * @param <E> The exception type of the visitor
+     * @return The result of the visitor
+     * @throws E The exception thrown by the visitor
+     */
     @Override
     public <T, E extends Exception> T visit(GeometryVisitor<T, E> visitor) throws E {
         return visitor.visit(this);
     }
 
+    /**
+     * @return True if this circle is empty (radius less than 0)
+     */
     @Override
     public boolean isEmpty() {
         return radiusMeters < 0;
@@ -141,6 +204,9 @@ public String toString() {
         return WellKnownText.INSTANCE.toWKT(this);
     }
 
+    /**
+     * @return True if this circle has an altitude. False if NaN.
+     */
     @Override
     public boolean hasZ() {
         return Double.isNaN(z) == false;
diff --git a/libs/geo/src/main/java/org/opensearch/geometry/GeometryCollection.java b/libs/geo/src/main/java/org/opensearch/geometry/GeometryCollection.java
index dfadf9269a097..8aca043017e32 100644
--- a/libs/geo/src/main/java/org/opensearch/geometry/GeometryCollection.java
+++ b/libs/geo/src/main/java/org/opensearch/geometry/GeometryCollection.java
@@ -88,6 +88,15 @@ public G get(int i) {
         return shapes.get(i);
     }
 
+    /**
+     * Returns a {@link List} of All {@link Geometry} present in this collection.
+     *
+     * @return a {@link List} of All {@link Geometry}
+     */
+    public List<G> getAll() {
+        return shapes;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15on-NOTICE.txt b/libs/grok/.attach_pid85116
similarity index 100%
rename from plugins/ingest-attachment/licenses/bcmail-jdk15on-NOTICE.txt
rename to libs/grok/.attach_pid85116
diff --git a/libs/grok/build.gradle b/libs/grok/build.gradle
index ce23406721fe6..97cf68a7971fa 100644
--- a/libs/grok/build.gradle
+++ b/libs/grok/build.gradle
@@ -29,9 +29,9 @@
  */
 
 dependencies {
-  api 'org.jruby.joni:joni:2.1.41'
+  api 'org.jruby.joni:joni:2.2.1'
   // joni dependencies:
-  api 'org.jruby.jcodings:jcodings:1.0.44'
+  api 'org.jruby.jcodings:jcodings:1.0.58'
 
   testImplementation(project(":test:framework")) {
     exclude group: 'org.opensearch', module: 'opensearch-grok'
@@ -41,7 +41,3 @@ dependencies {
 tasks.named('forbiddenApisMain').configure {
   replaceSignatureFiles 'jdk-signatures'
 }
-
-thirdPartyAudit.ignoreMissingClasses(
-  'org.jcodings.unicode.UnicodeCodeRange'
-)
\ No newline at end of file
diff --git a/libs/grok/licenses/jcodings-1.0.44.jar.sha1 b/libs/grok/licenses/jcodings-1.0.44.jar.sha1
deleted file mode 100644
index 4449009d3395e..0000000000000
--- a/libs/grok/licenses/jcodings-1.0.44.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a6884b2fd8fd9a56874db05afaa22435043a2e3e
\ No newline at end of file
diff --git a/libs/grok/licenses/jcodings-1.0.58.jar.sha1 b/libs/grok/licenses/jcodings-1.0.58.jar.sha1
new file mode 100644
index 0000000000000..0202d24704a50
--- /dev/null
+++ b/libs/grok/licenses/jcodings-1.0.58.jar.sha1
@@ -0,0 +1 @@
+dce27159dc0382e5f7518d4f3e499fc8396357ed
\ No newline at end of file
diff --git a/libs/grok/licenses/joni-2.1.41.jar.sha1 b/libs/grok/licenses/joni-2.1.41.jar.sha1
deleted file mode 100644
index 4f0a0a8393dd0..0000000000000
--- a/libs/grok/licenses/joni-2.1.41.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4a35f4eaef792073bc081b756b1f4949879cd41e
\ No newline at end of file
diff --git a/libs/grok/licenses/joni-2.2.1.jar.sha1 b/libs/grok/licenses/joni-2.2.1.jar.sha1
new file mode 100644
index 0000000000000..d0338540f5512
--- /dev/null
+++ b/libs/grok/licenses/joni-2.2.1.jar.sha1
@@ -0,0 +1 @@
+23d2f2eff7fa0cda465d86ec9d8bab53e496d9e6
\ No newline at end of file
diff --git a/libs/grok/src/main/java/org/opensearch/grok/Grok.java b/libs/grok/src/main/java/org/opensearch/grok/Grok.java
index e80bde02360ed..cd786b74be039 100644
--- a/libs/grok/src/main/java/org/opensearch/grok/Grok.java
+++ b/libs/grok/src/main/java/org/opensearch/grok/Grok.java
@@ -32,15 +32,6 @@
 
 package org.opensearch.grok;
 
-import org.jcodings.specific.UTF8Encoding;
-import org.joni.Matcher;
-import org.joni.NameEntry;
-import org.joni.Option;
-import org.joni.Regex;
-import org.joni.Region;
-import org.joni.Syntax;
-import org.joni.exception.ValueException;
-
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -56,6 +47,15 @@
 import java.util.Stack;
 import java.util.function.Consumer;
 
+import org.jcodings.specific.UTF8Encoding;
+import org.joni.Matcher;
+import org.joni.NameEntry;
+import org.joni.Option;
+import org.joni.Regex;
+import org.joni.Region;
+import org.joni.Syntax;
+import org.joni.exception.ValueException;
+
 import static java.util.Collections.unmodifiableList;
 
 public final class Grok {
@@ -214,8 +214,8 @@ private String groupMatch(String name, Region region, String pattern) {
                 name.getBytes(StandardCharsets.UTF_8).length,
                 region
             );
-            int begin = region.beg[number];
-            int end = region.end[number];
+            int begin = region.getBeg(number);
+            int end = region.getEnd(number);
             return new String(pattern.getBytes(StandardCharsets.UTF_8), begin, end - begin, StandardCharsets.UTF_8);
         } catch (StringIndexOutOfBoundsException e) {
             return null;
@@ -270,7 +270,12 @@ protected String toRegex(String grokPattern) {
                 grokPart = String.format(Locale.US, "(?<%s>%s)", patternName + "_" + result, pattern);
             }
             String start = new String(grokPatternBytes, 0, result, StandardCharsets.UTF_8);
-            String rest = new String(grokPatternBytes, region.end[0], grokPatternBytes.length - region.end[0], StandardCharsets.UTF_8);
+            String rest = new String(
+                grokPatternBytes,
+                region.getEnd(0),
+                grokPatternBytes.length - region.getEnd(0),
+                StandardCharsets.UTF_8
+            );
             grokPattern = grokPart + rest;
             res.append(start);
         }
diff --git a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureConfig.java b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureConfig.java
index 44be133b90fa6..6d1985f2165cd 100644
--- a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureConfig.java
+++ b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureConfig.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.grok;
 
-import org.joni.NameEntry;
-
 import java.nio.charset.StandardCharsets;
 import java.util.function.Consumer;
 import java.util.function.DoubleConsumer;
@@ -41,6 +39,8 @@
 import java.util.function.IntConsumer;
 import java.util.function.LongConsumer;
 
+import org.joni.NameEntry;
+
 /**
  * Configuration for a value that {@link Grok} can capture.
  */
diff --git a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureExtracter.java b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureExtracter.java
index b551150aac28c..b6d881de4fac1 100644
--- a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureExtracter.java
+++ b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureExtracter.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.grok;
 
-import org.joni.Region;
-
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.joni.Region;
+
 import static java.util.Collections.emptyMap;
 
 /**
diff --git a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureType.java b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureType.java
index f5898414827ff..0bd3bb47e55df 100644
--- a/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureType.java
+++ b/libs/grok/src/main/java/org/opensearch/grok/GrokCaptureType.java
@@ -33,11 +33,12 @@
 package org.opensearch.grok;
 
 import org.opensearch.grok.GrokCaptureConfig.NativeExtracterMap;
-import org.joni.Region;
 
 import java.nio.charset.StandardCharsets;
 import java.util.function.Consumer;
 
+import org.joni.Region;
+
 /**
  * The type defined for the field in the pattern.
  */
@@ -105,9 +106,9 @@ protected final GrokCaptureExtracter rawExtracter(int[] backRefs, Consumer<? sup
             @Override
             void extract(byte[] utf8Bytes, int offset, Region region) {
                 for (int number : backRefs) {
-                    if (region.beg[number] >= 0) {
-                        int matchOffset = offset + region.beg[number];
-                        int matchLength = region.end[number] - region.beg[number];
+                    if (region.getBeg(number) >= 0) {
+                        int matchOffset = offset + region.getBeg(number);
+                        int matchLength = region.getEnd(number) - region.getBeg(number);
                         emit.accept(new String(utf8Bytes, matchOffset, matchLength, StandardCharsets.UTF_8));
                         return; // Capture only the first value.
                     }
diff --git a/libs/grok/src/main/java/org/opensearch/grok/MatcherWatchdog.java b/libs/grok/src/main/java/org/opensearch/grok/MatcherWatchdog.java
index 70b4570ee69ad..5c7eaca2a634a 100644
--- a/libs/grok/src/main/java/org/opensearch/grok/MatcherWatchdog.java
+++ b/libs/grok/src/main/java/org/opensearch/grok/MatcherWatchdog.java
@@ -31,8 +31,6 @@
 
 package org.opensearch.grok;
 
-import org.joni.Matcher;
-
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -40,6 +38,8 @@
 import java.util.function.BiConsumer;
 import java.util.function.LongSupplier;
 
+import org.joni.Matcher;
+
 /**
  * Protects against long running operations that happen between the register and unregister invocations.
  * Threads that invoke {@link #register(Matcher)}, but take too long to invoke the {@link #unregister(Matcher)} method
diff --git a/libs/grok/src/main/resources/patterns/exim b/libs/grok/src/main/resources/patterns/exim
index 68c4e5cd7d0d7..e81eace04d32d 100644
--- a/libs/grok/src/main/resources/patterns/exim
+++ b/libs/grok/src/main/resources/patterns/exim
@@ -10,4 +10,3 @@ EXIM_PROTOCOL (P=%{NOTSPACE:protocol})
 EXIM_MSG_SIZE (S=%{NUMBER:exim_msg_size})
 EXIM_HEADER_ID (id=%{NOTSPACE:exim_header_id})
 EXIM_SUBJECT (T=%{QS:exim_subject})
-
diff --git a/libs/grok/src/main/resources/patterns/junos b/libs/grok/src/main/resources/patterns/junos
index 4eea59d08ccf9..2da91cc6ce3df 100644
--- a/libs/grok/src/main/resources/patterns/junos
+++ b/libs/grok/src/main/resources/patterns/junos
@@ -6,4 +6,3 @@ RT_FLOW1 %{RT_FLOW_EVENT:event}: %{GREEDYDATA:close-reason}: %{IP:src-ip}/%{INT:
 RT_FLOW2 %{RT_FLOW_EVENT:event}: session created %{IP:src-ip}/%{INT:src-port}->%{IP:dst-ip}/%{INT:dst-port} %{DATA:service} %{IP:nat-src-ip}/%{INT:nat-src-port}->%{IP:nat-dst-ip}/%{INT:nat-dst-port} %{DATA:src-nat-rule-name} %{DATA:dst-nat-rule-name} %{INT:protocol-id} %{DATA:policy-name} %{DATA:from-zone} %{DATA:to-zone} %{INT:session-id} .*
 
 RT_FLOW3 %{RT_FLOW_EVENT:event}: session denied %{IP:src-ip}/%{INT:src-port}->%{IP:dst-ip}/%{INT:dst-port} %{DATA:service} %{INT:protocol-id}\(\d\) %{DATA:policy-name} %{DATA:from-zone} %{DATA:to-zone} .*
-
diff --git a/libs/grok/src/main/resources/patterns/postgresql b/libs/grok/src/main/resources/patterns/postgresql
index c5b3e90b7250f..6901c6253e926 100644
--- a/libs/grok/src/main/resources/patterns/postgresql
+++ b/libs/grok/src/main/resources/patterns/postgresql
@@ -1,3 +1,2 @@
 # Default postgresql pg_log format pattern
 POSTGRESQL %{DATESTAMP:timestamp} %{TZ} %{DATA:user_id} %{GREEDYDATA:connection_id} %{POSINT:pid}
-
diff --git a/libs/grok/src/test/java/org/opensearch/grok/GrokTests.java b/libs/grok/src/test/java/org/opensearch/grok/GrokTests.java
index ed48585cc124a..a37689e051c67 100644
--- a/libs/grok/src/test/java/org/opensearch/grok/GrokTests.java
+++ b/libs/grok/src/test/java/org/opensearch/grok/GrokTests.java
@@ -51,34 +51,34 @@
 import java.util.function.IntConsumer;
 import java.util.function.LongConsumer;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.nullValue;
 import static org.opensearch.grok.GrokCaptureType.BOOLEAN;
 import static org.opensearch.grok.GrokCaptureType.DOUBLE;
 import static org.opensearch.grok.GrokCaptureType.FLOAT;
 import static org.opensearch.grok.GrokCaptureType.INTEGER;
 import static org.opensearch.grok.GrokCaptureType.LONG;
 import static org.opensearch.grok.GrokCaptureType.STRING;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
 
 public class GrokTests extends OpenSearchTestCase {
     public void testMatchWithoutCaptures() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "value", logger::warn);
-        assertThat(grok.captures("value"), equalTo(org.opensearch.common.collect.Map.of()));
-        assertThat(grok.captures("prefix_value"), equalTo(org.opensearch.common.collect.Map.of()));
+        assertThat(grok.captures("value"), equalTo(Map.of()));
+        assertThat(grok.captures("prefix_value"), equalTo(Map.of()));
         assertThat(grok.captures("no_match"), nullValue());
     }
 
     public void testCaputuresBytes() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "%{NUMBER:n:int}", logger::warn);
         byte[] utf8 = "10".getBytes(StandardCharsets.UTF_8);
-        assertThat(captureBytes(grok, utf8, 0, utf8.length), equalTo(org.opensearch.common.collect.Map.of("n", 10)));
-        assertThat(captureBytes(grok, utf8, 0, 1), equalTo(org.opensearch.common.collect.Map.of("n", 1)));
+        assertThat(captureBytes(grok, utf8, 0, utf8.length), equalTo(Map.of("n", 10)));
+        assertThat(captureBytes(grok, utf8, 0, 1), equalTo(Map.of("n", 1)));
         utf8 = "10 11 12".getBytes(StandardCharsets.UTF_8);
-        assertThat(captureBytes(grok, utf8, 0, 2), equalTo(org.opensearch.common.collect.Map.of("n", 10)));
-        assertThat(captureBytes(grok, utf8, 3, 2), equalTo(org.opensearch.common.collect.Map.of("n", 11)));
-        assertThat(captureBytes(grok, utf8, 6, 2), equalTo(org.opensearch.common.collect.Map.of("n", 12)));
+        assertThat(captureBytes(grok, utf8, 0, 2), equalTo(Map.of("n", 10)));
+        assertThat(captureBytes(grok, utf8, 3, 2), equalTo(Map.of("n", 11)));
+        assertThat(captureBytes(grok, utf8, 6, 2), equalTo(Map.of("n", 12)));
     }
 
     private Map<String, Object> captureBytes(Grok grok, byte[] utf8, int offset, int length) {
@@ -99,15 +99,15 @@ public void testSimpleSyslogLine() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "%{SYSLOGLINE}", logger::warn);
         assertCaptureConfig(
             grok,
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry("facility", STRING),
-                org.opensearch.common.collect.Map.entry("logsource", STRING),
-                org.opensearch.common.collect.Map.entry("message", STRING),
-                org.opensearch.common.collect.Map.entry("pid", STRING),
-                org.opensearch.common.collect.Map.entry("priority", STRING),
-                org.opensearch.common.collect.Map.entry("program", STRING),
-                org.opensearch.common.collect.Map.entry("timestamp", STRING),
-                org.opensearch.common.collect.Map.entry("timestamp8601", STRING)
+            Map.ofEntries(
+                Map.entry("facility", STRING),
+                Map.entry("logsource", STRING),
+                Map.entry("message", STRING),
+                Map.entry("pid", STRING),
+                Map.entry("priority", STRING),
+                Map.entry("program", STRING),
+                Map.entry("timestamp", STRING),
+                Map.entry("timestamp8601", STRING)
             )
         );
         Map<String, Object> matches = grok.captures(line);
@@ -134,16 +134,16 @@ public void testSyslog5424Line() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "%{SYSLOG5424LINE}", logger::warn);
         assertCaptureConfig(
             grok,
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry("syslog5424_app", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_host", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_msg", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_msgid", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_pri", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_proc", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_sd", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_ts", STRING),
-                org.opensearch.common.collect.Map.entry("syslog5424_ver", STRING)
+            Map.ofEntries(
+                Map.entry("syslog5424_app", STRING),
+                Map.entry("syslog5424_host", STRING),
+                Map.entry("syslog5424_msg", STRING),
+                Map.entry("syslog5424_msgid", STRING),
+                Map.entry("syslog5424_pri", STRING),
+                Map.entry("syslog5424_proc", STRING),
+                Map.entry("syslog5424_sd", STRING),
+                Map.entry("syslog5424_ts", STRING),
+                Map.entry("syslog5424_ver", STRING)
             )
         );
         Map<String, Object> matches = grok.captures(line);
@@ -161,14 +161,14 @@ public void testSyslog5424Line() {
     public void testDatePattern() {
         String line = "fancy 12-12-12 12:12:12";
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "(?<timestamp>%{DATE_EU} %{TIME})", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("timestamp", STRING));
+        assertCaptureConfig(grok, Map.of("timestamp", STRING));
         Map<String, Object> matches = grok.captures(line);
         assertEquals("12-12-12 12:12:12", matches.get("timestamp"));
     }
 
     public void testNilCoercedValues() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "test (N/A|%{BASE10NUM:duration:float}ms)", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("duration", FLOAT));
+        assertCaptureConfig(grok, Map.of("duration", FLOAT));
         Map<String, Object> matches = grok.captures("test 28.4ms");
         assertEquals(28.4f, matches.get("duration"));
         matches = grok.captures("test N/A");
@@ -177,7 +177,7 @@ public void testNilCoercedValues() {
 
     public void testNilWithNoCoercion() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "test (N/A|%{BASE10NUM:duration}ms)", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("duration", STRING));
+        assertCaptureConfig(grok, Map.of("duration", STRING));
         Map<String, Object> matches = grok.captures("test 28.4ms");
         assertEquals("28.4", matches.get("duration"));
         matches = grok.captures("test N/A");
@@ -194,13 +194,13 @@ public void testUnicodeSyslog() {
         );
         assertCaptureConfig(
             grok,
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry("syslog_hostname", STRING),
-                org.opensearch.common.collect.Map.entry("syslog_message", STRING),
-                org.opensearch.common.collect.Map.entry("syslog_pid", STRING),
-                org.opensearch.common.collect.Map.entry("syslog_pri", STRING),
-                org.opensearch.common.collect.Map.entry("syslog_program", STRING),
-                org.opensearch.common.collect.Map.entry("syslog_timestamp", STRING)
+            Map.ofEntries(
+                Map.entry("syslog_hostname", STRING),
+                Map.entry("syslog_message", STRING),
+                Map.entry("syslog_pid", STRING),
+                Map.entry("syslog_pri", STRING),
+                Map.entry("syslog_program", STRING),
+                Map.entry("syslog_timestamp", STRING)
             )
         );
         Map<String, Object> matches = grok.captures(
@@ -215,21 +215,21 @@ public void testUnicodeSyslog() {
 
     public void testNamedFieldsWithWholeTextMatch() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "%{DATE_EU:stimestamp}", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("stimestamp", STRING));
+        assertCaptureConfig(grok, Map.of("stimestamp", STRING));
         Map<String, Object> matches = grok.captures("11/01/01");
         assertThat(matches.get("stimestamp"), equalTo("11/01/01"));
     }
 
     public void testWithOniguramaNamedCaptures() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "(?<foo>\\w+)", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("foo", STRING));
+        assertCaptureConfig(grok, Map.of("foo", STRING));
         Map<String, Object> matches = grok.captures("hello world");
         assertThat(matches.get("foo"), equalTo("hello"));
     }
 
     public void testISO8601() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "^%{TIMESTAMP_ISO8601}$", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of());
+        assertCaptureConfig(grok, Map.of());
         List<String> timeMessages = Arrays.asList(
             "2001-01-01T00:00:00",
             "1974-03-02T04:09:09",
@@ -254,7 +254,7 @@ public void testISO8601() {
 
     public void testNotISO8601() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "^%{TIMESTAMP_ISO8601}$", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of());
+        assertCaptureConfig(grok, Map.of());
         List<String> timeMessages = Arrays.asList(
             "2001-13-01T00:00:00", // invalid month
             "2001-00-01T00:00:00", // invalid month
@@ -294,7 +294,7 @@ public void testNoNamedCaptures() {
         String text = "wowza !!!Tal!!! - Tal";
         String pattern = "%{EXCITED_NAME} - %{NAME}";
         Grok g = new Grok(bank, pattern, false, logger::warn);
-        assertCaptureConfig(g, org.opensearch.common.collect.Map.of("EXCITED_NAME_0", STRING, "NAME_21", STRING, "NAME_22", STRING));
+        assertCaptureConfig(g, Map.of("EXCITED_NAME_0", STRING, "NAME_21", STRING, "NAME_22", STRING));
 
         assertEquals("(?<EXCITED_NAME_0>!!!(?<NAME_21>Tal)!!!) - (?<NAME_22>Tal)", g.toRegex(pattern));
         assertEquals(true, g.match(text));
@@ -400,7 +400,7 @@ public void testMalformedPattern() {
     public void testBooleanCaptures() {
         String pattern = "%{WORD:name}=%{WORD:status:boolean}";
         Grok g = new Grok(Grok.BUILTIN_PATTERNS, pattern, logger::warn);
-        assertCaptureConfig(g, org.opensearch.common.collect.Map.of("name", STRING, "status", BOOLEAN));
+        assertCaptureConfig(g, Map.of("name", STRING, "status", BOOLEAN));
 
         String text = "active=true";
         Map<String, Object> expected = new HashMap<>();
@@ -428,7 +428,7 @@ public void testNumericCaptures() {
 
         String pattern = "%{NUMBER:bytes:float} %{NUMBER:id:long} %{NUMBER:rating:double}";
         Grok g = new Grok(bank, pattern, logger::warn);
-        assertCaptureConfig(g, org.opensearch.common.collect.Map.of("bytes", FLOAT, "id", LONG, "rating", DOUBLE));
+        assertCaptureConfig(g, Map.of("bytes", FLOAT, "id", LONG, "rating", DOUBLE));
 
         String text = "12009.34 20000000000 4820.092";
         Map<String, Object> expected = new HashMap<>();
@@ -476,7 +476,7 @@ public void testNumericCapturesCoercion() {
 
         String pattern = "%{NUMBER:bytes:float} %{NUMBER:status} %{NUMBER}";
         Grok g = new Grok(bank, pattern, logger::warn);
-        assertCaptureConfig(g, org.opensearch.common.collect.Map.of("bytes", FLOAT, "status", STRING));
+        assertCaptureConfig(g, Map.of("bytes", FLOAT, "status", STRING));
 
         String text = "12009.34 200 9032";
         Map<String, Object> expected = new HashMap<>();
@@ -494,8 +494,8 @@ public void testGarbageTypeNameBecomesString() {
 
         String pattern = "%{NUMBER:f:not_a_valid_type}";
         Grok g = new Grok(bank, pattern, logger::warn);
-        assertCaptureConfig(g, org.opensearch.common.collect.Map.of("f", STRING));
-        assertThat(g.captures("12009.34"), equalTo(org.opensearch.common.collect.Map.of("f", "12009.34")));
+        assertCaptureConfig(g, Map.of("f", STRING));
+        assertThat(g.captures("12009.34"), equalTo(Map.of("f", "12009.34")));
     }
 
     public void testApacheLog() {
@@ -505,19 +505,19 @@ public void testApacheLog() {
         Grok grok = new Grok(Grok.BUILTIN_PATTERNS, "%{COMBINEDAPACHELOG}", logger::warn);
         assertCaptureConfig(
             grok,
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry("agent", STRING),
-                org.opensearch.common.collect.Map.entry("auth", STRING),
-                org.opensearch.common.collect.Map.entry("bytes", STRING),
-                org.opensearch.common.collect.Map.entry("clientip", STRING),
-                org.opensearch.common.collect.Map.entry("httpversion", STRING),
-                org.opensearch.common.collect.Map.entry("ident", STRING),
-                org.opensearch.common.collect.Map.entry("rawrequest", STRING),
-                org.opensearch.common.collect.Map.entry("referrer", STRING),
-                org.opensearch.common.collect.Map.entry("request", STRING),
-                org.opensearch.common.collect.Map.entry("response", STRING),
-                org.opensearch.common.collect.Map.entry("timestamp", STRING),
-                org.opensearch.common.collect.Map.entry("verb", STRING)
+            Map.ofEntries(
+                Map.entry("agent", STRING),
+                Map.entry("auth", STRING),
+                Map.entry("bytes", STRING),
+                Map.entry("clientip", STRING),
+                Map.entry("httpversion", STRING),
+                Map.entry("ident", STRING),
+                Map.entry("rawrequest", STRING),
+                Map.entry("referrer", STRING),
+                Map.entry("request", STRING),
+                Map.entry("response", STRING),
+                Map.entry("timestamp", STRING),
+                Map.entry("verb", STRING)
             )
         );
         Map<String, Object> matches = grok.captures(logLine);
@@ -594,18 +594,18 @@ public void testComplete() {
         Grok grok = new Grok(bank, pattern, logger::warn);
         assertCaptureConfig(
             grok,
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry("agent", STRING),
-                org.opensearch.common.collect.Map.entry("auth", STRING),
-                org.opensearch.common.collect.Map.entry("bytes", INTEGER),
-                org.opensearch.common.collect.Map.entry("clientip", STRING),
-                org.opensearch.common.collect.Map.entry("httpversion", STRING),
-                org.opensearch.common.collect.Map.entry("ident", STRING),
-                org.opensearch.common.collect.Map.entry("referrer", STRING),
-                org.opensearch.common.collect.Map.entry("request", STRING),
-                org.opensearch.common.collect.Map.entry("response", INTEGER),
-                org.opensearch.common.collect.Map.entry("timestamp", STRING),
-                org.opensearch.common.collect.Map.entry("verb", STRING)
+            Map.ofEntries(
+                Map.entry("agent", STRING),
+                Map.entry("auth", STRING),
+                Map.entry("bytes", INTEGER),
+                Map.entry("clientip", STRING),
+                Map.entry("httpversion", STRING),
+                Map.entry("ident", STRING),
+                Map.entry("referrer", STRING),
+                Map.entry("request", STRING),
+                Map.entry("response", INTEGER),
+                Map.entry("timestamp", STRING),
+                Map.entry("verb", STRING)
             )
         );
 
@@ -642,7 +642,7 @@ public void testMultipleNamedCapturesWithSameName() {
         Map<String, String> bank = new HashMap<>();
         bank.put("SINGLEDIGIT", "[0-9]");
         Grok grok = new Grok(bank, "%{SINGLEDIGIT:num}%{SINGLEDIGIT:num}", logger::warn);
-        assertCaptureConfig(grok, org.opensearch.common.collect.Map.of("num", STRING));
+        assertCaptureConfig(grok, Map.of("num", STRING));
 
         Map<String, Object> expected = new HashMap<>();
         expected.put("num", "1");
diff --git a/libs/grok/src/test/java/org/opensearch/grok/MatcherWatchdogTests.java b/libs/grok/src/test/java/org/opensearch/grok/MatcherWatchdogTests.java
index 0290e200e4382..4a12ccab32f6a 100644
--- a/libs/grok/src/test/java/org/opensearch/grok/MatcherWatchdogTests.java
+++ b/libs/grok/src/test/java/org/opensearch/grok/MatcherWatchdogTests.java
@@ -31,24 +31,26 @@
 
 package org.opensearch.grok;
 
+import org.opensearch.test.OpenSearchTestCase;
+
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
-import org.opensearch.test.OpenSearchTestCase;
+
 import org.joni.Matcher;
 import org.mockito.Mockito;
 
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.timeout;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 public class MatcherWatchdogTests extends OpenSearchTestCase {
 
diff --git a/libs/nio/build.gradle b/libs/nio/build.gradle
index cae9f7e6feb26..1bd0c91135330 100644
--- a/libs/nio/build.gradle
+++ b/libs/nio/build.gradle
@@ -29,11 +29,11 @@
  */
 
 import org.opensearch.gradle.info.BuildParams
- 
+
 apply plugin: 'opensearch.publish'
 
 dependencies {
-  api project(':libs:opensearch-core')
+  api project(':libs:opensearch-common')
 
   testImplementation "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
   testImplementation "junit:junit:${versions.junit}"
diff --git a/libs/nio/src/main/java/org/opensearch/nio/SocketChannelContext.java b/libs/nio/src/main/java/org/opensearch/nio/SocketChannelContext.java
index 9cf57910a2b96..12a1e80055823 100644
--- a/libs/nio/src/main/java/org/opensearch/nio/SocketChannelContext.java
+++ b/libs/nio/src/main/java/org/opensearch/nio/SocketChannelContext.java
@@ -33,7 +33,7 @@
 package org.opensearch.nio;
 
 import org.opensearch.common.concurrent.CompletableContext;
-import org.opensearch.core.internal.net.NetUtils;
+import org.opensearch.common.util.net.NetUtils;
 import org.opensearch.nio.utils.ByteBufferUtils;
 import org.opensearch.nio.utils.ExceptionsHelper;
 
diff --git a/libs/nio/src/test/java/org/opensearch/nio/ChannelFactoryTests.java b/libs/nio/src/test/java/org/opensearch/nio/ChannelFactoryTests.java
index ba212de7941e5..0e4ec4a1b3bc5 100644
--- a/libs/nio/src/test/java/org/opensearch/nio/ChannelFactoryTests.java
+++ b/libs/nio/src/test/java/org/opensearch/nio/ChannelFactoryTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.nio;
 
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
diff --git a/libs/nio/src/test/java/org/opensearch/nio/NioSelectorTests.java b/libs/nio/src/test/java/org/opensearch/nio/NioSelectorTests.java
index 6af1cb64dac18..2fe5f3cc3f115 100644
--- a/libs/nio/src/test/java/org/opensearch/nio/NioSelectorTests.java
+++ b/libs/nio/src/test/java/org/opensearch/nio/NioSelectorTests.java
@@ -37,7 +37,6 @@
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -51,13 +50,15 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiConsumer;
 
+import org.mockito.ArgumentCaptor;
+
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyLong;
-import static org.mockito.Mockito.isNull;
-import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.isNull;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
diff --git a/libs/nio/src/test/java/org/opensearch/nio/SocketChannelContextTests.java b/libs/nio/src/test/java/org/opensearch/nio/SocketChannelContextTests.java
index 801ee7023482c..1e559b597ca89 100644
--- a/libs/nio/src/test/java/org/opensearch/nio/SocketChannelContextTests.java
+++ b/libs/nio/src/test/java/org/opensearch/nio/SocketChannelContextTests.java
@@ -35,8 +35,6 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
-import org.mockito.stubbing.Answer;
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
@@ -53,12 +51,15 @@
 import java.util.function.Consumer;
 import java.util.function.IntFunction;
 
+import org.mockito.ArgumentCaptor;
+import org.mockito.stubbing.Answer;
+
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
-import static org.mockito.Mockito.isNull;
-import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.isNull;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
diff --git a/libs/secure-sm/src/main/java/org/opensearch/secure_sm/SecuredForkJoinWorkerThreadFactory.java b/libs/secure-sm/src/main/java/org/opensearch/secure_sm/SecuredForkJoinWorkerThreadFactory.java
new file mode 100644
index 0000000000000..fe239fea8129e
--- /dev/null
+++ b/libs/secure-sm/src/main/java/org/opensearch/secure_sm/SecuredForkJoinWorkerThreadFactory.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.secure_sm;
+
+import java.security.AccessControlContext;
+import java.security.AccessController;
+import java.security.Permission;
+import java.security.Permissions;
+import java.security.PrivilegedAction;
+import java.security.ProtectionDomain;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory;
+import java.util.concurrent.ForkJoinWorkerThread;
+
+public class SecuredForkJoinWorkerThreadFactory implements ForkJoinWorkerThreadFactory {
+    static AccessControlContext contextWithPermissions(Permission... perms) {
+        Permissions permissions = new Permissions();
+        for (Permission perm : perms)
+            permissions.add(perm);
+        return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, permissions) });
+    }
+
+    // ACC for access to the factory
+    private static final AccessControlContext ACC = contextWithPermissions(
+        new RuntimePermission("getClassLoader"),
+        new RuntimePermission("setContextClassLoader"),
+        new RuntimePermission("modifyThreadGroup"),
+        new RuntimePermission("modifyThread")
+    );
+
+    public final ForkJoinWorkerThread newThread(ForkJoinPool pool) {
+        return AccessController.doPrivileged(new PrivilegedAction<>() {
+            public ForkJoinWorkerThread run() {
+                return new ForkJoinWorkerThread(pool) {
+
+                };
+            }
+        }, ACC);
+    }
+}
diff --git a/libs/secure-sm/src/test/java/org/opensearch/secure_sm/SecureSMTests.java b/libs/secure-sm/src/test/java/org/opensearch/secure_sm/SecureSMTests.java
index 8f184328957a1..026ffb080ee61 100644
--- a/libs/secure-sm/src/test/java/org/opensearch/secure_sm/SecureSMTests.java
+++ b/libs/secure-sm/src/test/java/org/opensearch/secure_sm/SecureSMTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.secure_sm;
 
-import junit.framework.TestCase;
-
 import java.security.Permission;
 import java.security.Policy;
 import java.security.ProtectionDomain;
 import java.util.Collections;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import junit.framework.TestCase;
+
 /** Simple tests for SecureSM */
 public class SecureSMTests extends TestCase {
     static {
diff --git a/libs/secure-sm/src/test/java/org/opensearch/secure_sm/ThreadPermissionTests.java b/libs/secure-sm/src/test/java/org/opensearch/secure_sm/ThreadPermissionTests.java
index 774e87f08c634..8d821f5bb27aa 100644
--- a/libs/secure-sm/src/test/java/org/opensearch/secure_sm/ThreadPermissionTests.java
+++ b/libs/secure-sm/src/test/java/org/opensearch/secure_sm/ThreadPermissionTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.secure_sm;
 
-import junit.framework.TestCase;
-
 import java.security.AllPermission;
 
+import junit.framework.TestCase;
+
 /**
  * Simple tests for ThreadPermission
  */
diff --git a/libs/ssl-config/build.gradle b/libs/ssl-config/build.gradle
index 740d5e309350c..3226ec12ff6f7 100644
--- a/libs/ssl-config/build.gradle
+++ b/libs/ssl-config/build.gradle
@@ -29,11 +29,11 @@
  */
 
 import org.opensearch.gradle.info.BuildParams
- 
+
 apply plugin: "opensearch.publish"
 
 dependencies {
-  api project(':libs:opensearch-core')
+  api project(':libs:opensearch-common')
 
   testImplementation(project(":test:framework")) {
     exclude group: 'org.opensearch', module: 'opensearch-ssl-config'
@@ -61,4 +61,3 @@ tasks.test {
         jvmArgs += ["--add-opens", "java.base/java.security.cert=ALL-UNNAMED"]
     }
 }
-
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DefaultJdkTrustConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DefaultJdkTrustConfig.java
index 04277e1528a92..859b74b200dc6 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DefaultJdkTrustConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DefaultJdkTrustConfig.java
@@ -36,6 +36,7 @@
 
 import javax.net.ssl.TrustManagerFactory;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.io.IOException;
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DiagnosticTrustManager.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DiagnosticTrustManager.java
index 75b0b831940d8..a3856038bbca1 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DiagnosticTrustManager.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/DiagnosticTrustManager.java
@@ -36,6 +36,7 @@
 import javax.net.ssl.SSLSession;
 import javax.net.ssl.SSLSocket;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.net.Socket;
 import java.security.GeneralSecurityException;
 import java.security.cert.CertificateException;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/EmptyKeyConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/EmptyKeyConfig.java
index ff5db9a04ff74..b5c7416c792a6 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/EmptyKeyConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/EmptyKeyConfig.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.nio.file.Path;
 import java.util.Collection;
 import java.util.Collections;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/KeyStoreUtil.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/KeyStoreUtil.java
index b2d5732022212..b6b6cdd90af14 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/KeyStoreUtil.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/KeyStoreUtil.java
@@ -40,6 +40,7 @@
 import javax.net.ssl.TrustManagerFactory;
 import javax.net.ssl.X509ExtendedKeyManager;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemKeyConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemKeyConfig.java
index 038299fd6d161..bfc29a5801b11 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemKeyConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemKeyConfig.java
@@ -34,6 +34,7 @@
 
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.nio.file.NoSuchFileException;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemTrustConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemTrustConfig.java
index 236ea6cd6f431..50b5887e7f355 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemTrustConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemTrustConfig.java
@@ -34,6 +34,7 @@
 
 import javax.net.ssl.TrustManagerFactory;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemUtils.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemUtils.java
index 533c8bf429e60..8a3730ee554f9 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemUtils.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/PemUtils.java
@@ -41,6 +41,7 @@
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.PBEKeySpec;
 import javax.crypto.spec.SecretKeySpec;
+
 import java.io.BufferedReader;
 import java.io.FileNotFoundException;
 import java.io.IOException;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslClientAuthenticationMode.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslClientAuthenticationMode.java
index e22ae45afd5fb..17d3749567990 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslClientAuthenticationMode.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslClientAuthenticationMode.java
@@ -32,6 +32,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.SSLParameters;
+
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Locale;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfiguration.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfiguration.java
index 27c3918ed6da0..23acb0ff269e2 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfiguration.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfiguration.java
@@ -35,6 +35,7 @@
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.X509ExtendedKeyManager;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
 import java.security.NoSuchAlgorithmException;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationKeys.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationKeys.java
index eb801bd124a50..5d28cbe1005b2 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationKeys.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationKeys.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.TrustManagerFactory;
+
 import java.security.KeyStore;
 import java.util.Arrays;
 import java.util.HashSet;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationLoader.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationLoader.java
index 6f2670d285e84..0b06a0692197e 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationLoader.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslConfigurationLoader.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.common.ssl;
 
-import org.opensearch.bootstrap.JavaVersion;
-
 import javax.crypto.Cipher;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
+
 import java.nio.file.Path;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
@@ -361,7 +360,6 @@ private <V> List<V> resolveListSetting(String key, Function<String, V> parser, L
 
     private static List<String> loadDefaultCiphers() {
         final boolean has256BitAES = has256BitAES();
-        final boolean useGCM = JavaVersion.current().compareTo(JavaVersion.parse("11")) >= 0;
         final boolean tlsV13Supported = DEFAULT_PROTOCOLS.contains("TLSv1.3");
         List<String> ciphers = new ArrayList<>();
         if (tlsV13Supported) { // TLSv1.3 cipher has PFS, AEAD, hardware support
@@ -370,19 +368,18 @@ private static List<String> loadDefaultCiphers() {
             }
             ciphers.add("TLS_AES_128_GCM_SHA256");
         }
-        if (useGCM) {  // PFS, AEAD, hardware support
-            if (has256BitAES) {
-                ciphers.addAll(
-                    Arrays.asList(
-                        "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
-                        "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
-                        "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
-                        "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"
-                    )
-                );
-            } else {
-                ciphers.addAll(Arrays.asList("TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"));
-            }
+        // use GCM: PFS, AEAD, hardware support
+        if (has256BitAES) {
+            ciphers.addAll(
+                Arrays.asList(
+                    "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
+                    "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
+                    "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
+                    "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"
+                )
+            );
+        } else {
+            ciphers.addAll(Arrays.asList("TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"));
         }
 
         // PFS, hardware support
@@ -410,13 +407,11 @@ private static List<String> loadDefaultCiphers() {
             );
         }
 
-        // AEAD, hardware support
-        if (useGCM) {
-            if (has256BitAES) {
-                ciphers.addAll(Arrays.asList("TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_GCM_SHA256"));
-            } else {
-                ciphers.add("TLS_RSA_WITH_AES_128_GCM_SHA256");
-            }
+        // use GCM: AEAD, hardware support
+        if (has256BitAES) {
+            ciphers.addAll(Arrays.asList("TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_GCM_SHA256"));
+        } else {
+            ciphers.add("TLS_RSA_WITH_AES_128_GCM_SHA256");
         }
 
         // hardware support
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslDiagnostics.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslDiagnostics.java
index 29de6f6d14031..f0a7d5bff4964 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslDiagnostics.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslDiagnostics.java
@@ -35,6 +35,7 @@
 import org.opensearch.common.Nullable;
 
 import javax.net.ssl.SSLSession;
+
 import java.security.cert.CertificateEncodingException;
 import java.security.cert.CertificateParsingException;
 import java.security.cert.X509Certificate;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslKeyConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslKeyConfig.java
index cb87965e83754..250c407a69bf5 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslKeyConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslKeyConfig.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.nio.file.Path;
 import java.util.Collection;
 
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslTrustConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslTrustConfig.java
index 38e51778da225..4dd5890f19311 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslTrustConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/SslTrustConfig.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.nio.file.Path;
 import java.util.Collection;
 
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreKeyConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreKeyConfig.java
index 42246d918192d..b3b7b7dc346a6 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreKeyConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreKeyConfig.java
@@ -34,6 +34,7 @@
 
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
 import java.security.KeyStore;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreTrustConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreTrustConfig.java
index d509956368a82..556cb052c4391 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreTrustConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/StoreTrustConfig.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.ssl;
 
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
 import java.security.KeyStore;
diff --git a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/TrustEverythingConfig.java b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/TrustEverythingConfig.java
index c8b6ab2407e69..c366210133687 100644
--- a/libs/ssl-config/src/main/java/org/opensearch/common/ssl/TrustEverythingConfig.java
+++ b/libs/ssl-config/src/main/java/org/opensearch/common/ssl/TrustEverythingConfig.java
@@ -34,6 +34,7 @@
 
 import javax.net.ssl.SSLEngine;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.net.Socket;
 import java.nio.file.Path;
 import java.security.cert.X509Certificate;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/DefaultJdkTrustConfigTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/DefaultJdkTrustConfigTests.java
index e767787d67d6d..dd325662ce50d 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/DefaultJdkTrustConfigTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/DefaultJdkTrustConfigTests.java
@@ -36,6 +36,7 @@
 import org.junit.Assert;
 
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.security.cert.X509Certificate;
 import java.util.Locale;
 import java.util.Optional;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemKeyConfigTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemKeyConfigTests.java
index 59d6a36b222ff..688f03a1e51fa 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemKeyConfigTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemKeyConfigTests.java
@@ -36,6 +36,7 @@
 import org.hamcrest.Matchers;
 
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemTrustConfigTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemTrustConfigTests.java
index 4617727d83857..e664e379d1e97 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemTrustConfigTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/PemTrustConfigTests.java
@@ -35,6 +35,8 @@
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
+import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
@@ -49,8 +51,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import javax.net.ssl.X509ExtendedTrustManager;
-
 public class PemTrustConfigTests extends OpenSearchTestCase {
 
     public void testBuildTrustConfigFromSinglePemFile() throws Exception {
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationLoaderTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationLoaderTests.java
index 19f4a85115236..5af7ddc73e680 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationLoaderTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationLoaderTests.java
@@ -33,12 +33,13 @@
 package org.opensearch.common.ssl;
 
 import org.opensearch.common.settings.MockSecureSettings;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.test.OpenSearchTestCase;
 
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
+
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.List;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationTests.java
index a629afc7f0d0b..ee907952c52ff 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslConfigurationTests.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.common.ssl;
 
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
-import org.mockito.Mockito;
 
 import javax.net.ssl.SSLContext;
+
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import org.mockito.Mockito;
+
 import static org.opensearch.common.ssl.SslConfigurationLoader.DEFAULT_CIPHERS;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslDiagnosticsTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslDiagnosticsTests.java
index 38ec0c3b5ff78..c966b4259219f 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslDiagnosticsTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/SslDiagnosticsTests.java
@@ -35,10 +35,10 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
-import org.mockito.Mockito;
 
 import javax.net.ssl.SSLSession;
 import javax.security.auth.x500.X500Principal;
+
 import java.io.IOException;
 import java.nio.file.Path;
 import java.security.PublicKey;
@@ -56,6 +56,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.mockito.Mockito;
+
 public class SslDiagnosticsTests extends OpenSearchTestCase {
 
     // Some constants for use in mock certificates
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreKeyConfigTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreKeyConfigTests.java
index de7420d27c170..7806671d02793 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreKeyConfigTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreKeyConfigTests.java
@@ -37,6 +37,7 @@
 
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.X509ExtendedKeyManager;
+
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
diff --git a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreTrustConfigTests.java b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreTrustConfigTests.java
index cbe0418f99ddf..5609f0fa2c877 100644
--- a/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreTrustConfigTests.java
+++ b/libs/ssl-config/src/test/java/org/opensearch/common/ssl/StoreTrustConfigTests.java
@@ -37,6 +37,7 @@
 
 import javax.net.ssl.TrustManagerFactory;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
diff --git a/libs/telemetry/build.gradle b/libs/telemetry/build.gradle
new file mode 100644
index 0000000000000..f8499482a6093
--- /dev/null
+++ b/libs/telemetry/build.gradle
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+dependencies {
+  api project(':libs:opensearch-common')
+
+  testImplementation "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
+  testImplementation "junit:junit:${versions.junit}"
+  testImplementation "org.hamcrest:hamcrest:${versions.hamcrest}"
+  testImplementation(project(":test:framework")) {
+    exclude group: 'org.opensearch', module: 'opensearch-telemetry'
+  }
+}
+
+tasks.named('forbiddenApisMain').configure {
+  replaceSignatureFiles 'jdk-signatures'
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/Telemetry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/Telemetry.java
new file mode 100644
index 0000000000000..0f973f50fc640
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/Telemetry.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.metrics.MetricsTelemetry;
+import org.opensearch.telemetry.tracing.TracingTelemetry;
+
+/**
+ * Interface defining telemetry
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface Telemetry {
+
+    /**
+     * Provides tracing telemetry
+     * @return tracing telemetry instance
+     */
+    TracingTelemetry getTracingTelemetry();
+
+    /**
+     * Provides metrics telemetry
+     * @return metrics telemetry instance
+     */
+    MetricsTelemetry getMetricsTelemetry();
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/Counter.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/Counter.java
new file mode 100644
index 0000000000000..c62288d280e2f
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/Counter.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.metrics.tags.Tags;
+
+/**
+ * Counter adds the value to the existing metric.
+ * {@opensearch.experimental}
+ */
+@ExperimentalApi
+public interface Counter {
+
+    /**
+     * add value.
+     * @param value value to be added.
+     */
+    void add(double value);
+
+    /**
+     * add value along with the attributes.
+     *
+     * @param value value to be added.
+     * @param tags  attributes/dimensions of the metric.
+     */
+    void add(double value, Tags tags);
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistry.java
new file mode 100644
index 0000000000000..d57def9406b17
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistry.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import java.io.IOException;
+
+/**
+ * Default implementation for {@link MetricsRegistry}
+ */
+class DefaultMetricsRegistry implements MetricsRegistry {
+    private final MetricsTelemetry metricsTelemetry;
+
+    /**
+     * Constructor
+     * @param metricsTelemetry metrics telemetry.
+     */
+    public DefaultMetricsRegistry(MetricsTelemetry metricsTelemetry) {
+        this.metricsTelemetry = metricsTelemetry;
+    }
+
+    @Override
+    public Counter createCounter(String name, String description, String unit) {
+        return metricsTelemetry.createCounter(name, description, unit);
+    }
+
+    @Override
+    public Counter createUpDownCounter(String name, String description, String unit) {
+        return metricsTelemetry.createUpDownCounter(name, description, unit);
+    }
+
+    @Override
+    public void close() throws IOException {
+        metricsTelemetry.close();
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistry.java
new file mode 100644
index 0000000000000..61b3df089928b
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistry.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.io.Closeable;
+
+/**
+ * MetricsRegistry helps in creating the metric instruments.
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface MetricsRegistry extends Closeable {
+
+    /**
+     * Creates the counter.
+     * @param name name of the counter.
+     * @param description any description about the metric.
+     * @param unit unit of the metric.
+     * @return counter.
+     */
+    Counter createCounter(String name, String description, String unit);
+
+    /**
+     * Creates the upDown counter.
+     * @param name name of the upDown counter.
+     * @param description any description about the metric.
+     * @param unit unit of the metric.
+     * @return counter.
+     */
+    Counter createUpDownCounter(String name, String description, String unit);
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsTelemetry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsTelemetry.java
new file mode 100644
index 0000000000000..2f70c28efb1cd
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/MetricsTelemetry.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.io.Closeable;
+
+/**
+ * Interface for metrics telemetry providers
+  *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface MetricsTelemetry extends MetricsRegistry, Closeable {
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopCounter.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopCounter.java
new file mode 100644
index 0000000000000..c1daf564dd3bc
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopCounter.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.metrics.Counter;
+import org.opensearch.telemetry.metrics.tags.Tags;
+
+/**
+ * No-op {@link Counter}
+ * {@opensearch.internal}
+ */
+@InternalApi
+public class NoopCounter implements Counter {
+
+    /**
+     * No-op Counter instance
+     */
+    public final static NoopCounter INSTANCE = new NoopCounter();
+
+    private NoopCounter() {}
+
+    @Override
+    public void add(double value) {
+
+    }
+
+    @Override
+    public void add(double value, Tags tags) {
+
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopMetricsRegistry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopMetricsRegistry.java
new file mode 100644
index 0000000000000..640c6842a8960
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/NoopMetricsRegistry.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.metrics.Counter;
+import org.opensearch.telemetry.metrics.MetricsRegistry;
+
+import java.io.IOException;
+
+/**
+ *No-op {@link MetricsRegistry}
+ * {@opensearch.internal}
+ */
+@InternalApi
+public class NoopMetricsRegistry implements MetricsRegistry {
+
+    /**
+     * No-op Meter instance
+     */
+    public final static NoopMetricsRegistry INSTANCE = new NoopMetricsRegistry();
+
+    private NoopMetricsRegistry() {}
+
+    @Override
+    public Counter createCounter(String name, String description, String unit) {
+        return NoopCounter.INSTANCE;
+    }
+
+    @Override
+    public Counter createUpDownCounter(String name, String description, String unit) {
+        return NoopCounter.INSTANCE;
+    }
+
+    @Override
+    public void close() throws IOException {
+
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/package-info.java
new file mode 100644
index 0000000000000..7c7ed08044993
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/noop/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains metrics related classes
+ * {@opensearch.internal}
+ */
+@InternalApi
+package org.opensearch.telemetry.metrics.noop;
+
+import org.opensearch.common.annotation.InternalApi;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/package-info.java
new file mode 100644
index 0000000000000..dfe17cc1c11ed
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains metrics related classes
+ */
+package org.opensearch.telemetry.metrics;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/Tags.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/Tags.java
new file mode 100644
index 0000000000000..f2a8764f8021d
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/Tags.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.tags;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Class to create tags for a meter.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public class Tags {
+    private final Map<String, Object> tagsMap;
+    /**
+     * Empty value.
+     */
+    public final static Tags EMPTY = new Tags(Collections.emptyMap());
+
+    /**
+     * Factory method.
+     * @return tags.
+     */
+    public static Tags create() {
+        return new Tags(new HashMap<>());
+    }
+
+    /**
+     * Constructor.
+     */
+    private Tags(Map<String, Object> tagsMap) {
+        this.tagsMap = tagsMap;
+    }
+
+    /**
+     * Add String attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Tags addTag(String key, String value) {
+        Objects.requireNonNull(value, "value cannot be null");
+        tagsMap.put(key, value);
+        return this;
+    }
+
+    /**
+     * Add long attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Tags addTag(String key, long value) {
+        tagsMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Add double attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Tags addTag(String key, double value) {
+        tagsMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Add boolean attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Tags addTag(String key, boolean value) {
+        tagsMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Returns the attribute map.
+     * @return tags map
+     */
+    public Map<String, ?> getTagsMap() {
+        return Collections.unmodifiableMap(tagsMap);
+    }
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/package-info.java
new file mode 100644
index 0000000000000..70bc9be992b32
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/metrics/tags/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains metrics related classes
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+package org.opensearch.telemetry.metrics.tags;
+
+import org.opensearch.common.annotation.ExperimentalApi;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/package-info.java
new file mode 100644
index 0000000000000..ad76f5e308bea
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains telemetry related classes
+ */
+package org.opensearch.telemetry;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/AbstractSpan.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/AbstractSpan.java
new file mode 100644
index 0000000000000..6919995e0ef65
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/AbstractSpan.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+/**
+ * Base span
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public abstract class AbstractSpan implements Span {
+
+    /**
+     * name of the span
+     */
+    private final String spanName;
+    /**
+     * span's parent span
+     */
+    private final Span parentSpan;
+
+    /**
+     * Base constructor
+     * @param spanName name of the span
+     * @param parentSpan span's parent span
+     */
+    protected AbstractSpan(String spanName, Span parentSpan) {
+        this.spanName = spanName;
+        this.parentSpan = parentSpan;
+    }
+
+    @Override
+    public Span getParentSpan() {
+        return parentSpan;
+    }
+
+    @Override
+    public String getSpanName() {
+        return spanName;
+    }
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultScopedSpan.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultScopedSpan.java
new file mode 100644
index 0000000000000..dc1a775839adb
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultScopedSpan.java
@@ -0,0 +1,92 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+import java.util.Objects;
+
+/**
+ * Default implementation of Scope
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+final class DefaultScopedSpan implements ScopedSpan {
+
+    private final Span span;
+
+    private final SpanScope spanScope;
+
+    /**
+     * Creates Scope instance for the given span
+     *
+     * @param span underlying span
+     * @param spanScope span scope.
+     */
+    public DefaultScopedSpan(Span span, SpanScope spanScope) {
+        this.span = Objects.requireNonNull(span);
+        this.spanScope = Objects.requireNonNull(spanScope);
+    }
+
+    @Override
+    public void addAttribute(String key, String value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, long value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, double value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, boolean value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addEvent(String event) {
+        span.addEvent(event);
+    }
+
+    @Override
+    public void setError(Exception exception) {
+        span.setError(exception);
+    }
+
+    /**
+     * Executes the runnable to end the scope
+     */
+    @Override
+    public void close() {
+        span.endSpan();
+        spanScope.close();
+    }
+
+    /**
+     * Returns span.
+     * @return the span associated with this scope
+     */
+    Span getSpan() {
+        return span;
+    }
+
+    /**
+     * Returns {@link SpanScope}
+     * @return spanScope
+     */
+    SpanScope getSpanScope() {
+        return spanScope;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultSpanScope.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultSpanScope.java
new file mode 100644
index 0000000000000..a5d515443b54d
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultSpanScope.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+import java.util.Objects;
+
+/**
+ * Default implementation for {@link SpanScope}
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+class DefaultSpanScope implements SpanScope {
+    private final Span span;
+    private final SpanScope previousSpanScope;
+    private static final ThreadLocal<SpanScope> spanScopeThreadLocal = new ThreadLocal<>();
+    private final TracerContextStorage<String, Span> tracerContextStorage;
+
+    /**
+     * Constructor
+     * @param span span
+     * @param previousSpanScope before attached span scope.
+     */
+    private DefaultSpanScope(Span span, SpanScope previousSpanScope, TracerContextStorage<String, Span> tracerContextStorage) {
+        this.span = Objects.requireNonNull(span);
+        this.previousSpanScope = previousSpanScope;
+        this.tracerContextStorage = tracerContextStorage;
+    }
+
+    /**
+     * Creates the SpanScope object.
+     * @param span span.
+     * @param tracerContextStorage tracer context storage.
+     * @return SpanScope spanScope
+     */
+    public static SpanScope create(Span span, TracerContextStorage<String, Span> tracerContextStorage) {
+        final SpanScope beforeSpanScope = spanScopeThreadLocal.get();
+        SpanScope newSpanScope = new DefaultSpanScope(span, beforeSpanScope, tracerContextStorage);
+        spanScopeThreadLocal.set(newSpanScope);
+        return newSpanScope;
+    }
+
+    @Override
+    public void close() {
+        detach();
+        spanScopeThreadLocal.set(previousSpanScope);
+    }
+
+    @Override
+    public SpanScope attach() {
+        tracerContextStorage.put(TracerContextStorage.CURRENT_SPAN, this.span);
+        return this;
+    }
+
+    private void detach() {
+        if (previousSpanScope != null) {
+            tracerContextStorage.put(TracerContextStorage.CURRENT_SPAN, previousSpanScope.getSpan());
+        } else {
+            tracerContextStorage.put(TracerContextStorage.CURRENT_SPAN, null);
+        }
+    }
+
+    @Override
+    public Span getSpan() {
+        return span;
+    }
+
+    static SpanScope getCurrentSpanScope() {
+        return spanScopeThreadLocal.get();
+    }
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultTracer.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultTracer.java
new file mode 100644
index 0000000000000..79b7e4aca6c2f
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultTracer.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+/**
+ *
+ * The default tracer implementation. It handles tracing context propagation between spans by maintaining
+ * current active span in its storage
+ *
+ *  @opensearch.internal
+ */
+@InternalApi
+class DefaultTracer implements Tracer {
+    /**
+     * Current thread name.
+     */
+    static final String THREAD_NAME = "thread.name";
+
+    private final TracingTelemetry tracingTelemetry;
+    private final TracerContextStorage<String, Span> tracerContextStorage;
+
+    /**
+     * Creates DefaultTracer instance
+     *
+     * @param tracingTelemetry tracing telemetry instance
+     * @param tracerContextStorage storage used for storing current span context
+     */
+    public DefaultTracer(TracingTelemetry tracingTelemetry, TracerContextStorage<String, Span> tracerContextStorage) {
+        this.tracingTelemetry = tracingTelemetry;
+        this.tracerContextStorage = tracerContextStorage;
+    }
+
+    @Override
+    public Span startSpan(SpanCreationContext context) {
+        Span parentSpan = null;
+        if (context.getParent() != null) {
+            parentSpan = context.getParent().getSpan();
+        } else {
+            parentSpan = getCurrentSpanInternal();
+        }
+        Span span = createSpan(context, parentSpan);
+        setCurrentSpanInContext(span);
+        addDefaultAttributes(span);
+        return span;
+    }
+
+    @Override
+    public void close() throws IOException {
+        ((Closeable) tracingTelemetry).close();
+    }
+
+    private Span getCurrentSpanInternal() {
+        return tracerContextStorage.get(TracerContextStorage.CURRENT_SPAN);
+    }
+
+    @Override
+    public SpanContext getCurrentSpan() {
+        final Span currentSpan = tracerContextStorage.get(TracerContextStorage.CURRENT_SPAN);
+        return (currentSpan == null) ? null : new SpanContext(currentSpan);
+    }
+
+    @Override
+    public ScopedSpan startScopedSpan(SpanCreationContext spanCreationContext) {
+        Span span = startSpan(spanCreationContext);
+        SpanScope spanScope = withSpanInScope(span);
+        return new DefaultScopedSpan(span, spanScope);
+    }
+
+    @Override
+    public SpanScope withSpanInScope(Span span) {
+        return DefaultSpanScope.create(span, tracerContextStorage).attach();
+    }
+
+    private Span createSpan(SpanCreationContext spanCreationContext, Span parentSpan) {
+        return tracingTelemetry.createSpan(spanCreationContext, parentSpan);
+    }
+
+    private void setCurrentSpanInContext(Span span) {
+        tracerContextStorage.put(TracerContextStorage.CURRENT_SPAN, span);
+    }
+
+    /**
+     * Adds default attributes in the span
+     * @param span the current active span
+     */
+    protected void addDefaultAttributes(Span span) {
+        span.addAttribute(THREAD_NAME, Thread.currentThread().getName());
+    }
+
+    @Override
+    public Span startSpan(SpanCreationContext spanCreationContext, Map<String, List<String>> headers) {
+        Optional<Span> propagatedSpan = tracingTelemetry.getContextPropagator().extractFromHeaders(headers);
+        return startSpan(spanCreationContext.parent(propagatedSpan.map(SpanContext::new).orElse(null)));
+    }
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/ScopedSpan.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/ScopedSpan.java
new file mode 100644
index 0000000000000..b320bc415de29
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/ScopedSpan.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.tracing.noop.NoopScopedSpan;
+
+/**
+ * An auto-closeable that represents scoped span.
+ * It provides interface for all the span operations.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface ScopedSpan extends AutoCloseable {
+    /**
+     * No-op Scope implementation
+     */
+    ScopedSpan NO_OP = new NoopScopedSpan();
+
+    /**
+     * Adds string attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addAttribute(String key, String value);
+
+    /**
+     * Adds long attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addAttribute(String key, long value);
+
+    /**
+     * Adds double attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addAttribute(String key, double value);
+
+    /**
+     * Adds boolean attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addAttribute(String key, boolean value);
+
+    /**
+     * Adds an event to the {@link Span}.
+     *
+     * @param event event name
+     */
+    void addEvent(String event);
+
+    /**
+     * Records error in the span
+     *
+     * @param exception exception to be recorded
+     */
+    void setError(Exception exception);
+
+    /**
+     * closes the scope
+     */
+    @Override
+    void close();
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Span.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Span.java
new file mode 100644
index 0000000000000..00b64492c281e
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Span.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+/**
+ * An interface that represents a tracing span.
+ * Spans are created by the Tracer.startSpan method.
+ * Span must be ended by calling SpanScope.close which internally calls Span's endSpan.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface Span {
+
+    /**
+     * Ends the span
+     */
+    void endSpan();
+
+    /**
+     * Returns span's parent span
+     */
+    Span getParentSpan();
+
+    /**
+     * Returns the name of the {@link Span}
+     */
+    String getSpanName();
+
+    /**
+     * Adds string type attribute in the span
+     *
+     * @param key of the attribute
+     * @param value value of the attribute
+     */
+    void addAttribute(String key, String value);
+
+    /**
+     * Adds long type attribute in the span
+     *
+     * @param key of the attribute
+     * @param value value of the attribute
+     */
+    void addAttribute(String key, Long value);
+
+    /**
+     * Adds double type attribute in the span
+     *
+     * @param key of the attribute
+     * @param value value of the attribute
+     */
+    void addAttribute(String key, Double value);
+
+    /**
+     * Adds boolean type attribute in the span
+     *
+     * @param key of the attribute
+     * @param value value of the attribute
+     */
+    void addAttribute(String key, Boolean value);
+
+    /**
+     * Records error in the span
+     *
+     * @param exception exception to be recorded
+     */
+    void setError(Exception exception);
+
+    /**
+     * Adds an event in the span
+     *
+     * @param event name of the event
+     */
+    void addEvent(String event);
+
+    /**
+     * Returns traceId of the span
+     * @return span's traceId
+     */
+    String getTraceId();
+
+    /**
+     * Returns spanId of the span
+     * @return span's spanId
+     */
+    String getSpanId();
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanContext.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanContext.java
new file mode 100644
index 0000000000000..f9af611553aff
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanContext.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+/**
+ * Wrapped Span will be exposed to the code outside of tracing package for sharing the {@link Span} without having access to
+ * its properties.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public final class SpanContext {
+    private final Span span;
+
+    /**
+     * Constructor.
+     * @param span span to be wrapped.
+     */
+    public SpanContext(Span span) {
+        this.span = span;
+    }
+
+    Span getSpan() {
+        return span;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanCreationContext.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanCreationContext.java
new file mode 100644
index 0000000000000..cbbcfe7a85d57
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanCreationContext.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+
+/**
+ * Context for span details.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public final class SpanCreationContext {
+    private String spanName;
+    private Attributes attributes;
+    private SpanKind spanKind = SpanKind.INTERNAL;
+    private SpanContext parent;
+
+    /**
+     * Constructor.
+     */
+    private SpanCreationContext() {}
+
+    /**
+     * Sets the span type to server.
+     * @return spanCreationContext
+     */
+    public static SpanCreationContext server() {
+        SpanCreationContext spanCreationContext = new SpanCreationContext();
+        spanCreationContext.spanKind = SpanKind.SERVER;
+        return spanCreationContext;
+    }
+
+    /**
+     * Sets the span type to client.
+     * @return spanCreationContext
+     */
+    public static SpanCreationContext client() {
+        SpanCreationContext spanCreationContext = new SpanCreationContext();
+        spanCreationContext.spanKind = SpanKind.CLIENT;
+        return spanCreationContext;
+    }
+
+    /**
+     * Sets the span type to internal.
+     * @return spanCreationContext
+     */
+    public static SpanCreationContext internal() {
+        SpanCreationContext spanCreationContext = new SpanCreationContext();
+        spanCreationContext.spanKind = SpanKind.INTERNAL;
+        return spanCreationContext;
+    }
+
+    /**
+     * Sets the span name.
+     * @param spanName span name.
+     * @return spanCreationContext
+     */
+    public SpanCreationContext name(String spanName) {
+        this.spanName = spanName;
+        return this;
+    }
+
+    /**
+     * Sets the span attributes.
+     * @param attributes attributes.
+     * @return spanCreationContext
+     */
+    public SpanCreationContext attributes(Attributes attributes) {
+        this.attributes = attributes;
+        return this;
+    }
+
+    /**
+     * Sets the parent for spann
+     * @param parent parent
+     * @return spanCreationContext
+     */
+    public SpanCreationContext parent(SpanContext parent) {
+        this.parent = parent;
+        return this;
+    }
+
+    /**
+     * Returns the span name.
+     * @return span name
+     */
+    public String getSpanName() {
+        return spanName;
+    }
+
+    /**
+     * Returns the span attributes.
+     * @return attributes.
+     */
+    public Attributes getAttributes() {
+        return attributes;
+    }
+
+    /**
+     * Returns the span kind.
+     * @return spankind.
+     */
+    public SpanKind getSpanKind() {
+        return spanKind;
+    }
+
+    /**
+     * Returns the parent span
+     * @return parent.
+     */
+    public SpanContext getParent() {
+        return parent;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanKind.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanKind.java
new file mode 100644
index 0000000000000..d674bb2c866f2
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanKind.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.PublicApi;
+
+/**
+ * Type of Span.
+ */
+@PublicApi(since = "2.11.0")
+public enum SpanKind {
+    /**
+     * Span represents the client side code.
+     */
+    CLIENT,
+    /**
+     * Span represents the server side code.
+     */
+    SERVER,
+
+    /**
+     * Span represents the internal calls. This is the default value of a span type.
+     */
+    INTERNAL;
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanReference.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanReference.java
new file mode 100644
index 0000000000000..945682c3df390
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanReference.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+/**
+ * Wrapper class to hold reference of Span
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+final class SpanReference {
+
+    private Span span;
+
+    /**
+     * Creates the wrapper with given span
+     * @param span the span object to wrap
+     */
+    public SpanReference(Span span) {
+        this.span = span;
+    }
+
+    /**
+     * Returns the span object
+     * @return underlying span
+     */
+    public Span getSpan() {
+        return span;
+    }
+
+    /**
+     * Updates the underlying span
+     * @param span underlying span
+     */
+    public void setSpan(Span span) {
+        this.span = span;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanScope.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanScope.java
new file mode 100644
index 0000000000000..8bccd5774a340
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanScope.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.tracing.noop.NoopSpanScope;
+
+/**
+ * An auto-closeable that represents scope of the span.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface SpanScope extends AutoCloseable {
+
+    /**
+     * No-op Scope implementation
+     */
+    SpanScope NO_OP = new NoopSpanScope();
+
+    @Override
+    void close();
+
+    /**
+     * Attaches span to the {@link SpanScope}
+     * @return spanScope
+     */
+    SpanScope attach();
+
+    /**
+     * Returns span attached with the {@link SpanScope}
+     * @return span.
+     */
+    Span getSpan();
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Tracer.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Tracer.java
new file mode 100644
index 0000000000000..49295f417df9e
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Tracer.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.tracing.http.HttpTracer;
+
+import java.io.Closeable;
+
+/**
+ * Tracer is the interface used to create a {@link Span}
+ * It automatically handles the context propagation between threads, tasks, nodes etc.
+ *
+ * All methods on the Tracer object are multi-thread safe.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface Tracer extends HttpTracer, Closeable {
+    /**
+     * Starts the {@link Span} with given {@link SpanCreationContext}
+     *
+     * @param context span context
+     * @return span, must be closed.
+     */
+    Span startSpan(SpanCreationContext context);
+
+    /**
+     * Returns the current span.
+     * @return current wrapped span.
+     */
+    SpanContext getCurrentSpan();
+
+    /**
+     * Start the span and scoped it. This must be used for scenarios where {@link SpanScope} and {@link Span} lifecycles
+     * are same and ends within the same thread where created.
+     * @param spanCreationContext span creation context
+     * @return scope of the span, must be closed with explicit close or with try-with-resource
+     */
+    ScopedSpan startScopedSpan(SpanCreationContext spanCreationContext);
+
+    /**
+     * Creates the Span Scope for a current thread. It's mandatory to scope the span just after creation so that it will
+     * automatically manage the attach /detach to the current thread.
+     * @param span span to be scoped
+     * @return ScopedSpan
+     */
+    SpanScope withSpanInScope(Span span);
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracerContextStorage.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracerContextStorage.java
new file mode 100644
index 0000000000000..958d054948483
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracerContextStorage.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+
+/**
+ * Storage interface used for storing tracing context
+ * @param <K> key type
+ * @param <V> value type
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public interface TracerContextStorage<K, V> {
+    /**
+     * Key for storing current span
+     */
+    String CURRENT_SPAN = "current_span";
+
+    /**
+     * Fetches value corresponding to key
+     * @param key of the tracing context
+     * @return value for key
+     */
+    V get(K key);
+
+    /**
+     * Puts tracing context value with key
+     * @param key of the tracing context
+     * @param value of the tracing context
+     */
+    void put(K key, V value);
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingContextPropagator.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingContextPropagator.java
new file mode 100644
index 0000000000000..5fbc5d329e227
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingContextPropagator.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.BiConsumer;
+
+/**
+ * Interface defining the tracing related context propagation
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface TracingContextPropagator {
+
+    /**
+     * Extracts current span from context
+     * @param props properties
+     * @return current span
+     */
+    Optional<Span> extract(Map<String, String> props);
+
+    /**
+     * Extracts current span from HTTP headers.
+     *
+     * @param headers request headers to extract the context from
+     * @return current span
+     */
+    Optional<Span> extractFromHeaders(Map<String, List<String>> headers);
+
+    /**
+     * Injects tracing context
+     *
+     * @param currentSpan the current active span
+     * @param setter to add tracing context in map
+     */
+    void inject(Span currentSpan, BiConsumer<String, String> setter);
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingTelemetry.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingTelemetry.java
new file mode 100644
index 0000000000000..f04a505088424
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/TracingTelemetry.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.io.Closeable;
+
+/**
+ * Interface for tracing telemetry providers
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface TracingTelemetry extends Closeable {
+
+    /**
+     * Creates span with provided arguments
+     *
+     * @param spanCreationContext span creation context.
+     * @param parentSpan parent span.
+     * @return span instance
+     */
+    Span createSpan(SpanCreationContext spanCreationContext, Span parentSpan);
+
+    /**
+     * provides tracing context propagator
+     * @return tracing context propagator instance
+     */
+    TracingContextPropagator getContextPropagator();
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/Attributes.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/Attributes.java
new file mode 100644
index 0000000000000..6dcc9c5468b38
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/Attributes.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.attributes;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Class to create attributes for a span.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public class Attributes {
+    private final Map<String, Object> attributesMap;
+    /**
+     * Empty value.
+     */
+    public final static Attributes EMPTY = new Attributes(Collections.emptyMap());
+
+    /**
+     * Factory method.
+     * @return attributes.
+     */
+    public static Attributes create() {
+        return new Attributes(new HashMap<>());
+    }
+
+    /**
+     * Constructor.
+     */
+    private Attributes(Map<String, Object> attributesMap) {
+        this.attributesMap = attributesMap;
+    }
+
+    /**
+     * Add String attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Attributes addAttribute(String key, String value) {
+        Objects.requireNonNull(value, "value cannot be null");
+        attributesMap.put(key, value);
+        return this;
+    }
+
+    /**
+     * Add long attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Attributes addAttribute(String key, long value) {
+        attributesMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Add double attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Attributes addAttribute(String key, double value) {
+        attributesMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Add boolean attribute.
+     * @param key key
+     * @param value value
+     * @return Same instance.
+     */
+    public Attributes addAttribute(String key, boolean value) {
+        attributesMap.put(key, value);
+        return this;
+    };
+
+    /**
+     * Returns the attribute map.
+     * @return attributes map
+     */
+    public Map<String, ?> getAttributesMap() {
+        return Collections.unmodifiableMap(attributesMap);
+    }
+
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/package-info.java
new file mode 100644
index 0000000000000..ccd56786f63ef
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/attributes/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains attributes management
+ */
+package org.opensearch.telemetry.tracing.attributes;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/HttpTracer.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/HttpTracer.java
new file mode 100644
index 0000000000000..b0692f1b62a48
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/HttpTracer.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.http;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanCreationContext;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * HttpTracer helps in creating a {@link Span} which reads the incoming tracing information
+ * from the HttpRequest header and propagate the span accordingly.
+ *
+ * All methods on the Tracer object are multi-thread safe.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface HttpTracer {
+    /**
+     * Start the span with propagating the tracing info from the HttpRequest header.
+     *
+     * @param spanCreationContext span name.
+     * @param header http request header.
+     * @return span.
+     */
+    Span startSpan(SpanCreationContext spanCreationContext, Map<String, List<String>> header);
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/package-info.java
new file mode 100644
index 0000000000000..9feb862a4e010
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/http/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains No-op implementations
+ */
+package org.opensearch.telemetry.tracing.http;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopScopedSpan.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopScopedSpan.java
new file mode 100644
index 0000000000000..fc296d3689645
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopScopedSpan.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.tracing.ScopedSpan;
+
+/**
+ * No-op implementation of SpanScope
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public final class NoopScopedSpan implements ScopedSpan {
+
+    /**
+     * No-args constructor
+     */
+    public NoopScopedSpan() {}
+
+    @Override
+    public void addAttribute(String key, String value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, long value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, double value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, boolean value) {
+
+    }
+
+    @Override
+    public void addEvent(String event) {
+
+    }
+
+    @Override
+    public void setError(Exception exception) {
+
+    }
+
+    @Override
+    public void close() {
+
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpan.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpan.java
new file mode 100644
index 0000000000000..f41e11017d155
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpan.java
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.tracing.Span;
+
+/**
+ * No-op implementation of {@link org.opensearch.telemetry.tracing.Span}
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class NoopSpan implements Span {
+
+    /**
+     * No-op Span instance
+     */
+    public final static NoopSpan INSTANCE = new NoopSpan();
+
+    private NoopSpan() {
+
+    }
+
+    @Override
+    public void endSpan() {
+
+    }
+
+    @Override
+    public Span getParentSpan() {
+        return null;
+    }
+
+    @Override
+    public String getSpanName() {
+        return "noop-span";
+    }
+
+    @Override
+    public void addAttribute(String key, String value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, Long value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, Double value) {
+
+    }
+
+    @Override
+    public void addAttribute(String key, Boolean value) {
+
+    }
+
+    @Override
+    public void setError(Exception exception) {
+
+    }
+
+    @Override
+    public void addEvent(String event) {
+
+    }
+
+    @Override
+    public String getTraceId() {
+        return "noop-trace-id";
+    }
+
+    @Override
+    public String getSpanId() {
+        return "noop-span-id";
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpanScope.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpanScope.java
new file mode 100644
index 0000000000000..bb04a67657d6e
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopSpanScope.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanScope;
+
+/**
+ * No-op implementation of {@link SpanScope}
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class NoopSpanScope implements SpanScope {
+    /**
+     * Constructor.
+     */
+    public NoopSpanScope() {
+
+    }
+
+    @Override
+    public void close() {
+
+    }
+
+    @Override
+    public SpanScope attach() {
+        return this;
+    }
+
+    @Override
+    public Span getSpan() {
+        return NoopSpan.INSTANCE;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopTracer.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopTracer.java
new file mode 100644
index 0000000000000..c073e8d3e766f
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/NoopTracer.java
@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.noop;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.tracing.ScopedSpan;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanContext;
+import org.opensearch.telemetry.tracing.SpanCreationContext;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * No-op implementation of Tracer
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class NoopTracer implements Tracer {
+
+    /**
+     * No-op Tracer instance
+     */
+    public static final Tracer INSTANCE = new NoopTracer();
+
+    private NoopTracer() {}
+
+    @Override
+    public Span startSpan(SpanCreationContext context) {
+        return NoopSpan.INSTANCE;
+    }
+
+    @Override
+    public SpanContext getCurrentSpan() {
+        return new SpanContext(NoopSpan.INSTANCE);
+    }
+
+    @Override
+    public ScopedSpan startScopedSpan(SpanCreationContext spanCreationContext) {
+        return ScopedSpan.NO_OP;
+    }
+
+    @Override
+    public SpanScope withSpanInScope(Span span) {
+        return SpanScope.NO_OP;
+    }
+
+    @Override
+    public void close() {
+
+    }
+
+    @Override
+    public Span startSpan(SpanCreationContext spanCreationContext, Map<String, List<String>> header) {
+        return NoopSpan.INSTANCE;
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/package-info.java
new file mode 100644
index 0000000000000..b9d83e7bc7275
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/noop/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains No-op implementations
+ */
+package org.opensearch.telemetry.tracing.noop;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/package-info.java
new file mode 100644
index 0000000000000..66898bd58b753
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains tracing related classes
+ */
+package org.opensearch.telemetry.tracing;
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/TraceableRunnable.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/TraceableRunnable.java
new file mode 100644
index 0000000000000..8a61dd70d6d54
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/TraceableRunnable.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.runnable;
+
+import org.opensearch.telemetry.tracing.ScopedSpan;
+import org.opensearch.telemetry.tracing.SpanCreationContext;
+import org.opensearch.telemetry.tracing.Tracer;
+
+/**
+ * Wraps the runnable and add instrumentation to trace the {@link Runnable}
+ */
+public class TraceableRunnable implements Runnable {
+    private final Runnable runnable;
+    private final SpanCreationContext spanCreationContext;
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     * @param tracer tracer
+     * @param spanCreationContext spanCreationContext
+     * @param runnable runnable.
+     */
+    public TraceableRunnable(Tracer tracer, SpanCreationContext spanCreationContext, Runnable runnable) {
+        this.tracer = tracer;
+        this.spanCreationContext = spanCreationContext;
+        this.runnable = runnable;
+    }
+
+    @Override
+    public void run() {
+        try (ScopedSpan spanScope = tracer.startScopedSpan(spanCreationContext)) {
+            runnable.run();
+        }
+    }
+}
diff --git a/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/package-info.java b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/package-info.java
new file mode 100644
index 0000000000000..9f696a4ac573e
--- /dev/null
+++ b/libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/runnable/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Contains tracing related classes
+ */
+package org.opensearch.telemetry.tracing.runnable;
diff --git a/libs/telemetry/src/test/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistryTests.java b/libs/telemetry/src/test/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistryTests.java
new file mode 100644
index 0000000000000..6171641db5f07
--- /dev/null
+++ b/libs/telemetry/src/test/java/org/opensearch/telemetry/metrics/DefaultMetricsRegistryTests.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class DefaultMetricsRegistryTests extends OpenSearchTestCase {
+
+    private MetricsTelemetry metricsTelemetry;
+    private DefaultMetricsRegistry defaultMeterRegistry;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        metricsTelemetry = mock(MetricsTelemetry.class);
+        defaultMeterRegistry = new DefaultMetricsRegistry(metricsTelemetry);
+    }
+
+    public void testCounter() {
+        Counter mockCounter = mock(Counter.class);
+        when(defaultMeterRegistry.createCounter(any(String.class), any(String.class), any(String.class))).thenReturn(mockCounter);
+        Counter counter = defaultMeterRegistry.createCounter(
+            "org.opensearch.telemetry.metrics.DefaultMeterRegistryTests.testCounter",
+            "test counter",
+            "1"
+        );
+        assertSame(mockCounter, counter);
+    }
+
+    public void testUpDownCounter() {
+        Counter mockCounter = mock(Counter.class);
+        when(defaultMeterRegistry.createUpDownCounter(any(String.class), any(String.class), any(String.class))).thenReturn(mockCounter);
+        Counter counter = defaultMeterRegistry.createUpDownCounter(
+            "org.opensearch.telemetry.metrics.DefaultMeterRegistryTests.testUpDownCounter",
+            "test up-down counter",
+            "1"
+        );
+        assertSame(mockCounter, counter);
+    }
+
+}
diff --git a/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultScopedSpanTests.java b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultScopedSpanTests.java
new file mode 100644
index 0000000000000..1d4871fe1419e
--- /dev/null
+++ b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultScopedSpanTests.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+public class DefaultScopedSpanTests extends OpenSearchTestCase {
+
+    @SuppressWarnings("unchecked")
+    public void testClose() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.close();
+
+        verify(mockSpan).endSpan();
+        verify(mockSpanScope).close();
+    }
+
+    public void testAddSpanAttributeString() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.addAttribute("key", "value");
+
+        verify(mockSpan).addAttribute("key", "value");
+    }
+
+    public void testAddSpanAttributeLong() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.addAttribute("key", 1L);
+
+        verify(mockSpan).addAttribute("key", 1L);
+    }
+
+    public void testAddSpanAttributeDouble() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.addAttribute("key", 1.0);
+
+        verify(mockSpan).addAttribute("key", 1.0);
+    }
+
+    public void testAddSpanAttributeBoolean() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.addAttribute("key", true);
+
+        verify(mockSpan).addAttribute("key", true);
+    }
+
+    public void testAddEvent() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        defaultSpanScope.addEvent("eventName");
+
+        verify(mockSpan).addEvent("eventName");
+    }
+
+    public void testSetError() {
+        Span mockSpan = mock(Span.class);
+        SpanScope mockSpanScope = mock(SpanScope.class);
+        DefaultScopedSpan defaultSpanScope = new DefaultScopedSpan(mockSpan, mockSpanScope);
+        Exception ex = new Exception("error");
+        defaultSpanScope.setError(ex);
+
+        verify(mockSpan).setError(ex);
+    }
+
+}
diff --git a/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultTracerTests.java b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultTracerTests.java
new file mode 100644
index 0000000000000..0a717e993cb81
--- /dev/null
+++ b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/DefaultTracerTests.java
@@ -0,0 +1,425 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.node.Node;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.telemetry.tracing.MockSpan;
+import org.opensearch.test.telemetry.tracing.MockTracingTelemetry;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class DefaultTracerTests extends OpenSearchTestCase {
+
+    private TracingTelemetry mockTracingTelemetry;
+    private TracerContextStorage<String, Span> mockTracerContextStorage;
+    private Span mockSpan;
+    private Span mockParentSpan;
+
+    private SpanScope mockSpanScope;
+    private ThreadPool threadPool;
+    private ExecutorService executorService;
+    private SpanCreationContext spanCreationContext;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new ThreadPool(Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), "default tracer tests").build());
+        executorService = threadPool.executor(ThreadPool.Names.GENERIC);
+        setupMocks();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        executorService.shutdown();
+        threadPool.shutdownNow();
+    }
+
+    public void testCreateSpan() {
+        DefaultTracer defaultTracer = new DefaultTracer(mockTracingTelemetry, mockTracerContextStorage);
+
+        defaultTracer.startSpan(spanCreationContext);
+
+        String spanName = defaultTracer.getCurrentSpan().getSpan().getSpanName();
+        assertEquals("span_name", spanName);
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testCreateSpanWithAttributesWithMock() {
+        DefaultTracer defaultTracer = new DefaultTracer(mockTracingTelemetry, mockTracerContextStorage);
+        Attributes attributes = Attributes.create().addAttribute("name", "value");
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", attributes, mockParentSpan);
+        when(mockTracingTelemetry.createSpan(eq(spanCreationContext), eq(mockParentSpan))).thenReturn(mockSpan);
+        defaultTracer.startSpan(spanCreationContext);
+        verify(mockTracingTelemetry).createSpan(eq(spanCreationContext), eq(mockParentSpan));
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testCreateSpanWithAttributesWithParentMock() {
+        DefaultTracer defaultTracer = new DefaultTracer(mockTracingTelemetry, mockTracerContextStorage);
+        Attributes attributes = Attributes.create().addAttribute("name", "value");
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", attributes, mockParentSpan);
+        when(mockTracingTelemetry.createSpan(eq(spanCreationContext), eq(mockParentSpan))).thenReturn(mockSpan);
+        defaultTracer.startSpan(spanCreationContext);
+        verify(mockTracingTelemetry).createSpan(eq(spanCreationContext), eq(mockParentSpan));
+        verify(mockTracerContextStorage, never()).get(TracerContextStorage.CURRENT_SPAN);
+    }
+
+    public void testCreateSpanWithAttributes() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        DefaultTracer defaultTracer = new DefaultTracer(
+            tracingTelemetry,
+            new ThreadContextBasedTracerContextStorage(threadContext, tracingTelemetry)
+        );
+
+        SpanCreationContext spanCreationContext = buildSpanCreationContext(
+            "span_name",
+            Attributes.create().addAttribute("key1", 1.0).addAttribute("key2", 2l).addAttribute("key3", true).addAttribute("key4", "key4"),
+            null
+        );
+
+        Span span = defaultTracer.startSpan(spanCreationContext);
+
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(1.0, ((MockSpan) defaultTracer.getCurrentSpan().getSpan()).getAttribute("key1"));
+        assertEquals(2l, ((MockSpan) defaultTracer.getCurrentSpan().getSpan()).getAttribute("key2"));
+        assertEquals(true, ((MockSpan) defaultTracer.getCurrentSpan().getSpan()).getAttribute("key3"));
+        assertEquals("key4", ((MockSpan) defaultTracer.getCurrentSpan().getSpan()).getAttribute("key4"));
+        span.endSpan();
+    }
+
+    public void testCreateSpanWithParent() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        DefaultTracer defaultTracer = new DefaultTracer(
+            tracingTelemetry,
+            new ThreadContextBasedTracerContextStorage(new ThreadContext(Settings.EMPTY), tracingTelemetry)
+        );
+
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", null, null);
+
+        Span span = defaultTracer.startSpan(spanCreationContext, null);
+
+        SpanContext parentSpan = defaultTracer.getCurrentSpan();
+
+        SpanCreationContext spanCreationContext1 = buildSpanCreationContext("span_name_1", Attributes.EMPTY, parentSpan.getSpan());
+
+        Span span1 = defaultTracer.startSpan(spanCreationContext1);
+
+        assertEquals("span_name_1", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(parentSpan.getSpan(), defaultTracer.getCurrentSpan().getSpan().getParentSpan());
+        span1.endSpan();
+        span.endSpan();
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testCreateSpanWithContext() {
+        DefaultTracer defaultTracer = new DefaultTracer(mockTracingTelemetry, mockTracerContextStorage);
+        Attributes attributes = Attributes.create().addAttribute("name", "value");
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", attributes, mockParentSpan);
+        when(mockTracingTelemetry.createSpan(eq(spanCreationContext), eq(mockParentSpan))).thenReturn(mockSpan);
+        defaultTracer.startSpan(spanCreationContext);
+        verify(mockTracingTelemetry).createSpan(eq(spanCreationContext), eq(mockParentSpan));
+    }
+
+    public void testCreateSpanWithNullParent() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        DefaultTracer defaultTracer = new DefaultTracer(
+            tracingTelemetry,
+            new ThreadContextBasedTracerContextStorage(threadContext, tracingTelemetry)
+        );
+
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", Attributes.EMPTY, null);
+
+        Span span = defaultTracer.startSpan(spanCreationContext);
+
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(null, defaultTracer.getCurrentSpan().getSpan().getParentSpan());
+        span.endSpan();
+    }
+
+    public void testEndSpanByClosingScopedSpan() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", Attributes.EMPTY, null);
+
+        ScopedSpan scopedSpan = defaultTracer.startScopedSpan(spanCreationContext);
+
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(((DefaultScopedSpan) scopedSpan).getSpanScope(), DefaultSpanScope.getCurrentSpanScope());
+        scopedSpan.close();
+        assertTrue(((MockSpan) ((DefaultScopedSpan) scopedSpan).getSpan()).hasEnded());
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertEquals(null, DefaultSpanScope.getCurrentSpanScope());
+
+    }
+
+    public void testEndSpanByClosingScopedSpanMultiple() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", Attributes.EMPTY, null);
+        SpanCreationContext spanCreationContext1 = buildSpanCreationContext("span_name_1", Attributes.EMPTY, null);
+
+        ScopedSpan scopedSpan = defaultTracer.startScopedSpan(spanCreationContext);
+        ScopedSpan scopedSpan1 = defaultTracer.startScopedSpan(spanCreationContext1);
+
+        assertEquals("span_name_1", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(((DefaultScopedSpan) scopedSpan1).getSpanScope(), DefaultSpanScope.getCurrentSpanScope());
+
+        scopedSpan1.close();
+        assertTrue(((MockSpan) ((DefaultScopedSpan) scopedSpan1).getSpan()).hasEnded());
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(((DefaultScopedSpan) scopedSpan).getSpanScope(), DefaultSpanScope.getCurrentSpanScope());
+
+        scopedSpan.close();
+        assertTrue(((MockSpan) ((DefaultScopedSpan) scopedSpan).getSpan()).hasEnded());
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertEquals(null, DefaultSpanScope.getCurrentSpanScope());
+
+    }
+
+    public void testEndSpanByClosingSpanScope() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+        SpanCreationContext spanCreationContext = buildSpanCreationContext("span_name", Attributes.EMPTY, null);
+        Span span = defaultTracer.startSpan(spanCreationContext);
+        SpanScope spanScope = defaultTracer.withSpanInScope(span);
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(spanScope, DefaultSpanScope.getCurrentSpanScope());
+
+        span.endSpan();
+        spanScope.close();
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertTrue(((MockSpan) span).hasEnded());
+
+    }
+
+    public void testEndSpanByClosingSpanScopeMultiple() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+        Span span = defaultTracer.startSpan(buildSpanCreationContext("span_name", Attributes.EMPTY, null));
+        Span span1 = defaultTracer.startSpan(buildSpanCreationContext("span_name_1", Attributes.EMPTY, null));
+        SpanScope spanScope = defaultTracer.withSpanInScope(span);
+        SpanScope spanScope1 = defaultTracer.withSpanInScope(span1);
+        assertEquals("span_name_1", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(spanScope1, DefaultSpanScope.getCurrentSpanScope());
+
+        span1.endSpan();
+        spanScope1.close();
+
+        assertEquals("span_name", defaultTracer.getCurrentSpan().getSpan().getSpanName());
+        assertEquals(spanScope, DefaultSpanScope.getCurrentSpanScope());
+        assertTrue(((MockSpan) span1).hasEnded());
+        assertFalse(((MockSpan) span).hasEnded());
+        span.endSpan();
+        spanScope.close();
+
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertEquals(null, DefaultSpanScope.getCurrentSpanScope());
+        assertTrue(((MockSpan) span).hasEnded());
+        assertTrue(((MockSpan) span1).hasEnded());
+
+    }
+
+    /**
+     * 1. CreateSpan in ThreadA (NotScopedSpan)
+     * 2. create Async task and pass the span
+     * 3. Scope.close
+     * 4. verify the current_span is still the same on async thread as the 2
+     * 5. verify the main thread has current span as null.
+     */
+    public void testSpanAcrossThreads() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+
+        CompletableFuture<?> asyncTask = CompletableFuture.runAsync(() -> {
+            // create a span
+            Span span = defaultTracer.startSpan(buildSpanCreationContext("span_name_t_1", Attributes.EMPTY, null));
+            SpanScope spanScope = defaultTracer.withSpanInScope(span);
+
+            CompletableFuture<?> asyncTask1 = CompletableFuture.runAsync(() -> {
+                Span spanT2 = defaultTracer.startSpan(buildSpanCreationContext("span_name_t_2", Attributes.EMPTY, null));
+                SpanScope spanScopeT2 = defaultTracer.withSpanInScope(spanT2);
+                assertEquals(spanT2, defaultTracer.getCurrentSpan().getSpan());
+
+                spanScopeT2.close();
+                spanT2.endSpan();
+                assertEquals(null, defaultTracer.getCurrentSpan());
+            }, executorService);
+            asyncTask1.join();
+            spanScope.close();
+            span.endSpan();
+            assertEquals(null, defaultTracer.getCurrentSpan());
+        }, executorService);
+        asyncTask.join();
+    }
+
+    public void testSpanCloseOnThread2() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+        final Span span = defaultTracer.startSpan(buildSpanCreationContext("span_name_t1", Attributes.EMPTY, null));
+        try (SpanScope spanScope = defaultTracer.withSpanInScope(span)) {
+            CompletableFuture<?> asyncTask = CompletableFuture.runAsync(() -> async(new ActionListener<Boolean>() {
+                @Override
+                public void onResponse(Boolean response) {
+                    try (SpanScope s = defaultTracer.withSpanInScope(span)) {
+                        assertEquals(span, defaultTracer.getCurrentSpan().getSpan());
+                    } finally {
+                        span.endSpan();
+                    }
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+
+                }
+            }), executorService);
+            assertEquals(span, defaultTracer.getCurrentSpan().getSpan());
+            asyncTask.join();
+        }
+        assertEquals(null, defaultTracer.getCurrentSpan());
+    }
+
+    private void async(ActionListener<Boolean> actionListener) {
+        actionListener.onResponse(true);
+    }
+
+    /**
+     * 1. CreateSpan in ThreadA (NotScopedSpan)
+     * 2. create Async task and pass the span
+     * 3. Inside Async task start a new span.
+     * 4. Scope.close
+     * 5. Parent Scope.close
+     * 6. verify the current_span is still the same on async thread as the 2
+     * 7. verify the main thread has current span as null.
+     */
+    public void testSpanAcrossThreadsMultipleSpans() {
+        TracingTelemetry tracingTelemetry = new MockTracingTelemetry();
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+
+        ThreadContextBasedTracerContextStorage spanTracerStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        DefaultTracer defaultTracer = new DefaultTracer(tracingTelemetry, spanTracerStorage);
+
+        CompletableFuture<?> asyncTask = CompletableFuture.runAsync(() -> {
+            // create a parent span
+            Span parentSpan = defaultTracer.startSpan(buildSpanCreationContext("p_span_name", Attributes.EMPTY, null));
+            SpanScope parentSpanScope = defaultTracer.withSpanInScope(parentSpan);
+            // create a span
+            Span span = defaultTracer.startSpan(buildSpanCreationContext("span_name_t_1", Attributes.EMPTY, null));
+            SpanScope spanScope = defaultTracer.withSpanInScope(span);
+
+            CompletableFuture<?> asyncTask1 = CompletableFuture.runAsync(() -> {
+                Span spanT2 = defaultTracer.startSpan(buildSpanCreationContext("span_name_t_2", Attributes.EMPTY, null));
+                SpanScope spanScopeT2 = defaultTracer.withSpanInScope(spanT2);
+                Span spanT21 = defaultTracer.startSpan(buildSpanCreationContext("span_name_t_2", Attributes.EMPTY, null));
+                SpanScope spanScopeT21 = defaultTracer.withSpanInScope(spanT21);
+                assertEquals(spanT21, defaultTracer.getCurrentSpan().getSpan());
+                spanScopeT21.close();
+                spanT21.endSpan();
+
+                spanScopeT2.close();
+                spanT2.endSpan();
+
+                assertEquals(null, defaultTracer.getCurrentSpan());
+            }, executorService);
+
+            asyncTask1.join();
+
+            spanScope.close();
+            span.endSpan();
+            parentSpanScope.close();
+            parentSpan.endSpan();
+            assertEquals(null, defaultTracer.getCurrentSpan());
+        }, executorService);
+        asyncTask.join();
+    }
+
+    public void testClose() throws IOException {
+        Tracer defaultTracer = new DefaultTracer(mockTracingTelemetry, mockTracerContextStorage);
+
+        defaultTracer.close();
+
+        verify(mockTracingTelemetry).close();
+    }
+
+    @SuppressWarnings("unchecked")
+    private void setupMocks() {
+        mockTracingTelemetry = mock(TracingTelemetry.class);
+        mockSpan = mock(Span.class);
+        mockParentSpan = mock(Span.class);
+        mockSpanScope = mock(SpanScope.class);
+        mockTracerContextStorage = mock(TracerContextStorage.class);
+        when(mockSpan.getSpanName()).thenReturn("span_name");
+        when(mockSpan.getSpanId()).thenReturn("span_id");
+        when(mockSpan.getTraceId()).thenReturn("trace_id");
+        when(mockSpan.getParentSpan()).thenReturn(mockParentSpan);
+        when(mockParentSpan.getSpanId()).thenReturn("parent_span_id");
+        when(mockParentSpan.getTraceId()).thenReturn("trace_id");
+        spanCreationContext = buildSpanCreationContext("span_name", Attributes.EMPTY, mockParentSpan);
+        when(mockTracerContextStorage.get(TracerContextStorage.CURRENT_SPAN)).thenReturn(mockSpan, mockParentSpan);
+        when(mockTracingTelemetry.createSpan(eq(spanCreationContext), eq(mockParentSpan))).thenReturn(mockSpan);
+    }
+
+    private SpanCreationContext buildSpanCreationContext(String spanName, Attributes attributes, Span parentSpan) {
+        SpanCreationContext spanCreationContext = SpanCreationContext.internal().name(spanName).attributes(attributes);
+        if (parentSpan != null) {
+            spanCreationContext.parent(new SpanContext(parentSpan));
+        }
+        return spanCreationContext;
+    }
+}
diff --git a/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/TraceableRunnableTests.java b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/TraceableRunnableTests.java
new file mode 100644
index 0000000000000..4c4f762653d57
--- /dev/null
+++ b/libs/telemetry/src/test/java/org/opensearch/telemetry/tracing/TraceableRunnableTests.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.telemetry.tracing.runnable.TraceableRunnable;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.telemetry.tracing.MockSpan;
+import org.opensearch.test.telemetry.tracing.MockTracingTelemetry;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+
+public class TraceableRunnableTests extends OpenSearchTestCase {
+
+    private final ThreadContextBasedTracerContextStorage contextStorage = new ThreadContextBasedTracerContextStorage(
+        new ThreadContext(Settings.EMPTY),
+        new MockTracingTelemetry()
+    );
+
+    public void testRunnableWithNullParent() throws Exception {
+        String spanName = "testRunnable";
+        final DefaultTracer defaultTracer = new DefaultTracer(new MockTracingTelemetry(), contextStorage);
+        final AtomicBoolean isRunnableCompleted = new AtomicBoolean(false);
+        final AtomicReference<String> spanNameCaptured = new AtomicReference<>();
+        final AtomicReference<String> attributeValue = new AtomicReference<>();
+        TraceableRunnable traceableRunnable = new TraceableRunnable(
+            defaultTracer,
+            SpanCreationContext.internal().name(spanName).attributes(Attributes.create().addAttribute("name", "value")),
+            () -> {
+                spanNameCaptured.set(defaultTracer.getCurrentSpan().getSpan().getSpanName());
+                attributeValue.set((String) ((MockSpan) defaultTracer.getCurrentSpan().getSpan()).getAttribute("name"));
+                isRunnableCompleted.set(true);
+            }
+        );
+        traceableRunnable.run();
+        assertTrue(isRunnableCompleted.get());
+        assertEquals(spanName, spanNameCaptured.get());
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertEquals(null, defaultTracer.getCurrentSpan());
+        assertEquals("value", attributeValue.get());
+    }
+
+    public void testRunnableWithParent() throws Exception {
+        String spanName = "testRunnable";
+        String parentSpanName = "parentSpan";
+        DefaultTracer defaultTracer = new DefaultTracer(new MockTracingTelemetry(), contextStorage);
+        ScopedSpan scopedSpan = defaultTracer.startScopedSpan(
+            SpanCreationContext.internal().name(parentSpanName).attributes(Attributes.EMPTY)
+        );
+        SpanContext parentSpanContext = defaultTracer.getCurrentSpan();
+        AtomicReference<SpanContext> currentSpan = new AtomicReference<>();
+        final AtomicBoolean isRunnableCompleted = new AtomicBoolean(false);
+        TraceableRunnable traceableRunnable = new TraceableRunnable(
+            defaultTracer,
+            SpanCreationContext.internal()
+                .name(spanName)
+                .attributes(Attributes.create().addAttribute("name", "value"))
+                .parent(parentSpanContext),
+            () -> {
+                isRunnableCompleted.set(true);
+                currentSpan.set(defaultTracer.getCurrentSpan());
+            }
+        );
+        traceableRunnable.run();
+        assertTrue(isRunnableCompleted.get());
+        assertEquals(spanName, currentSpan.get().getSpan().getSpanName());
+        assertEquals(((DefaultScopedSpan) scopedSpan).getSpan(), currentSpan.get().getSpan().getParentSpan());
+        assertEquals(((DefaultScopedSpan) scopedSpan).getSpan(), defaultTracer.getCurrentSpan().getSpan());
+        scopedSpan.close();
+    }
+}
diff --git a/libs/x-content/build.gradle b/libs/x-content/build.gradle
index 3d0465783d7a0..dab07c5af336a 100644
--- a/libs/x-content/build.gradle
+++ b/libs/x-content/build.gradle
@@ -32,6 +32,7 @@ apply plugin: 'opensearch.build'
 apply plugin: 'opensearch.publish'
 
 dependencies {
+  api project(':libs:opensearch-common')
   api project(':libs:opensearch-core')
 
   api "org.yaml:snakeyaml:${versions.snakeyaml}"
@@ -47,6 +48,7 @@ dependencies {
   testImplementation(project(":test:framework")) {
     exclude group: 'org.opensearch', module: 'opensearch-x-content'
   }
+  testImplementation(project(":libs:opensearch-core"))
 
 }
 
diff --git a/libs/x-content/licenses/jackson-core-2.13.2.jar.sha1 b/libs/x-content/licenses/jackson-core-2.13.2.jar.sha1
deleted file mode 100644
index eb8a8bc45f041..0000000000000
--- a/libs/x-content/licenses/jackson-core-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0a6a0e0620d51833feffc67bccb51937b2345763
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-core-2.15.2.jar.sha1 b/libs/x-content/licenses/jackson-core-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..ec6781b968eed
--- /dev/null
+++ b/libs/x-content/licenses/jackson-core-2.15.2.jar.sha1
@@ -0,0 +1 @@
+a6fe1836469a69b3ff66037c324d75fc66ef137c
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-cbor-2.13.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-cbor-2.13.2.jar.sha1
deleted file mode 100644
index 3a4f0e1b17565..0000000000000
--- a/libs/x-content/licenses/jackson-dataformat-cbor-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4fc77e1ec6922fc48bf1181e4b38f600dac222ff
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-cbor-2.15.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-cbor-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..0022265a84b68
--- /dev/null
+++ b/libs/x-content/licenses/jackson-dataformat-cbor-2.15.2.jar.sha1
@@ -0,0 +1 @@
+baafc85c70765594add14bd93f3efd68e1945b76
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-smile-2.13.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-smile-2.13.2.jar.sha1
deleted file mode 100644
index 86a53f72de66e..0000000000000
--- a/libs/x-content/licenses/jackson-dataformat-smile-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-984bb22f310ebbedc967d206e672f8acf766a98e
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-smile-2.15.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-smile-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..2b8caad846fec
--- /dev/null
+++ b/libs/x-content/licenses/jackson-dataformat-smile-2.15.2.jar.sha1
@@ -0,0 +1 @@
+16d1dd22f7d641459ed056399d4f7df0220f1176
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-yaml-2.13.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-yaml-2.13.2.jar.sha1
deleted file mode 100644
index 1cba175acf2ae..0000000000000
--- a/libs/x-content/licenses/jackson-dataformat-yaml-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-5601496b5b6e43d947aeeffbffadb2b18961c731
\ No newline at end of file
diff --git a/libs/x-content/licenses/jackson-dataformat-yaml-2.15.2.jar.sha1 b/libs/x-content/licenses/jackson-dataformat-yaml-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..4ad7255e2318f
--- /dev/null
+++ b/libs/x-content/licenses/jackson-dataformat-yaml-2.15.2.jar.sha1
@@ -0,0 +1 @@
+58194ff9f51915ad6bf6b6f24818232d7566418a
\ No newline at end of file
diff --git a/libs/x-content/licenses/snakeyaml-1.26.jar.sha1 b/libs/x-content/licenses/snakeyaml-1.26.jar.sha1
deleted file mode 100644
index fde3aba8edad0..0000000000000
--- a/libs/x-content/licenses/snakeyaml-1.26.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a78a8747147d2c5807683e76ec2b633e95c14fe9
\ No newline at end of file
diff --git a/libs/x-content/licenses/snakeyaml-2.1.jar.sha1 b/libs/x-content/licenses/snakeyaml-2.1.jar.sha1
new file mode 100644
index 0000000000000..5586b210a9736
--- /dev/null
+++ b/libs/x-content/licenses/snakeyaml-2.1.jar.sha1
@@ -0,0 +1 @@
+c79f47315517560b5bd6a62376ee385e48105437
\ No newline at end of file
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentFactory.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentFactory.java
index 63b1ef6af752d..9f423bc9abad3 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentFactory.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentFactory.java
@@ -32,29 +32,26 @@
 
 package org.opensearch.common.xcontent;
 
-import com.fasterxml.jackson.dataformat.cbor.CBORConstants;
-import com.fasterxml.jackson.dataformat.smile.SmileConstants;
-import org.opensearch.common.xcontent.cbor.CborXContent;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.smile.SmileXContent;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.OutputStream;
 
 /**
- * A one stop to use {@link org.opensearch.common.xcontent.XContent} and {@link XContentBuilder}.
+ * A one stop to use {@link XContent} and {@link XContentBuilder}.
  */
 public class XContentFactory {
 
-    static final int GUESS_HEADER_LENGTH = 20;
-
     /**
      * Returns a content builder using JSON format ({@link org.opensearch.common.xcontent.XContentType#JSON}.
      */
     public static XContentBuilder jsonBuilder() throws IOException {
-        return contentBuilder(XContentType.JSON);
+        return MediaTypeRegistry.contentBuilder(XContentType.JSON);
     }
 
     /**
@@ -68,7 +65,7 @@ public static XContentBuilder jsonBuilder(OutputStream os) throws IOException {
      * Returns a content builder using SMILE format ({@link org.opensearch.common.xcontent.XContentType#SMILE}.
      */
     public static XContentBuilder smileBuilder() throws IOException {
-        return contentBuilder(XContentType.SMILE);
+        return MediaTypeRegistry.contentBuilder(XContentType.SMILE);
     }
 
     /**
@@ -82,7 +79,7 @@ public static XContentBuilder smileBuilder(OutputStream os) throws IOException {
      * Returns a content builder using YAML format ({@link org.opensearch.common.xcontent.XContentType#YAML}.
      */
     public static XContentBuilder yamlBuilder() throws IOException {
-        return contentBuilder(XContentType.YAML);
+        return MediaTypeRegistry.contentBuilder(XContentType.YAML);
     }
 
     /**
@@ -96,261 +93,6 @@ public static XContentBuilder yamlBuilder(OutputStream os) throws IOException {
      * Returns a content builder using CBOR format ({@link org.opensearch.common.xcontent.XContentType#CBOR}.
      */
     public static XContentBuilder cborBuilder() throws IOException {
-        return contentBuilder(XContentType.CBOR);
-    }
-
-    /**
-     * Constructs a new cbor builder that will output the result into the provided output stream.
-     */
-    public static XContentBuilder cborBuilder(OutputStream os) throws IOException {
-        return new XContentBuilder(CborXContent.cborXContent, os);
-    }
-
-    /**
-     * Constructs a xcontent builder that will output the result into the provided output stream.
-     */
-    public static XContentBuilder contentBuilder(XContentType type, OutputStream outputStream) throws IOException {
-        if (type == XContentType.JSON) {
-            return jsonBuilder(outputStream);
-        } else if (type == XContentType.SMILE) {
-            return smileBuilder(outputStream);
-        } else if (type == XContentType.YAML) {
-            return yamlBuilder(outputStream);
-        } else if (type == XContentType.CBOR) {
-            return cborBuilder(outputStream);
-        }
-        throw new IllegalArgumentException("No matching content type for " + type);
-    }
-
-    /**
-     * Returns a binary content builder for the provided content type.
-     */
-    public static XContentBuilder contentBuilder(XContentType type) throws IOException {
-        if (type == XContentType.JSON) {
-            return JsonXContent.contentBuilder();
-        } else if (type == XContentType.SMILE) {
-            return SmileXContent.contentBuilder();
-        } else if (type == XContentType.YAML) {
-            return YamlXContent.contentBuilder();
-        } else if (type == XContentType.CBOR) {
-            return CborXContent.contentBuilder();
-        }
-        throw new IllegalArgumentException("No matching content type for " + type);
-    }
-
-    /**
-     * Returns the {@link org.opensearch.common.xcontent.XContent} for the provided content type.
-     */
-    public static XContent xContent(XContentType type) {
-        if (type == null) {
-            throw new IllegalArgumentException("Cannot get xcontent for unknown type");
-        }
-        return type.xContent();
-    }
-
-    /**
-     * Guesses the content type based on the provided char sequence.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContentType xContentType(CharSequence content) {
-        int length = content.length() < GUESS_HEADER_LENGTH ? content.length() : GUESS_HEADER_LENGTH;
-        if (length == 0) {
-            return null;
-        }
-        char first = content.charAt(0);
-        if (first == '{') {
-            return XContentType.JSON;
-        }
-        // Should we throw a failure here? Smile idea is to use it in bytes....
-        if (length > 2
-            && first == SmileConstants.HEADER_BYTE_1
-            && content.charAt(1) == SmileConstants.HEADER_BYTE_2
-            && content.charAt(2) == SmileConstants.HEADER_BYTE_3) {
-            return XContentType.SMILE;
-        }
-        if (length > 2 && first == '-' && content.charAt(1) == '-' && content.charAt(2) == '-') {
-            return XContentType.YAML;
-        }
-
-        // CBOR is not supported
-
-        for (int i = 0; i < length; i++) {
-            char c = content.charAt(i);
-            if (c == '{') {
-                return XContentType.JSON;
-            }
-            if (Character.isWhitespace(c) == false) {
-                break;
-            }
-        }
-        return null;
-    }
-
-    /**
-     * Guesses the content (type) based on the provided char sequence and returns the corresponding {@link XContent}
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContent xContent(CharSequence content) {
-        XContentType type = xContentType(content);
-        if (type == null) {
-            throw new XContentParseException("Failed to derive xcontent");
-        }
-        return xContent(type);
-    }
-
-    /**
-     * Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContent xContent(byte[] data) {
-        return xContent(data, 0, data.length);
-    }
-
-    /**
-     * Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
-     *
-     * @deprecated guessing the content type should not be needed ideally. We should rather know the content type upfront or read it
-     * from headers. Till we fixed the REST layer to read the Content-Type header, that should be the only place where guessing is needed.
-     */
-    @Deprecated
-    public static XContent xContent(byte[] data, int offset, int length) {
-        XContentType type = xContentType(data, offset, length);
-        if (type == null) {
-            throw new XContentParseException("Failed to derive xcontent");
-        }
-        return xContent(type);
-    }
-
-    /**
-     * Guesses the content type based on the provided input stream without consuming it.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContentType xContentType(InputStream si) throws IOException {
-        /*
-         * We need to guess the content type. To do this, we look for the first non-whitespace character and then try to guess the content
-         * type on the GUESS_HEADER_LENGTH bytes that follow. We do this in a way that does not modify the initial read position in the
-         * underlying input stream. This is why the input stream must support mark/reset and why we repeatedly mark the read position and
-         * reset.
-         */
-        if (si.markSupported() == false) {
-            throw new IllegalArgumentException("Cannot guess the xcontent type without mark/reset support on " + si.getClass());
-        }
-        si.mark(Integer.MAX_VALUE);
-        try {
-            // scan until we find the first non-whitespace character or the end of the stream
-            int current;
-            do {
-                current = si.read();
-                if (current == -1) {
-                    return null;
-                }
-            } while (Character.isWhitespace((char) current));
-            // now guess the content type off the next GUESS_HEADER_LENGTH bytes including the current byte
-            final byte[] firstBytes = new byte[GUESS_HEADER_LENGTH];
-            firstBytes[0] = (byte) current;
-            int read = 1;
-            while (read < GUESS_HEADER_LENGTH) {
-                final int r = si.read(firstBytes, read, GUESS_HEADER_LENGTH - read);
-                if (r == -1) {
-                    break;
-                }
-                read += r;
-            }
-            return xContentType(firstBytes, 0, read);
-        } finally {
-            si.reset();
-        }
-
-    }
-
-    /**
-     * Guesses the content type based on the provided bytes.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContentType xContentType(byte[] bytes) {
-        return xContentType(bytes, 0, bytes.length);
-    }
-
-    /**
-     * Guesses the content type based on the provided bytes.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContentType xContentType(byte[] bytes, int offset, int length) {
-        int totalLength = bytes.length;
-        if (totalLength == 0 || length == 0) {
-            return null;
-        } else if ((offset + length) > totalLength) {
-            return null;
-        }
-        byte first = bytes[offset];
-        if (first == '{') {
-            return XContentType.JSON;
-        }
-        if (length > 2
-            && first == SmileConstants.HEADER_BYTE_1
-            && bytes[offset + 1] == SmileConstants.HEADER_BYTE_2
-            && bytes[offset + 2] == SmileConstants.HEADER_BYTE_3) {
-            return XContentType.SMILE;
-        }
-        if (length > 2 && first == '-' && bytes[offset + 1] == '-' && bytes[offset + 2] == '-') {
-            return XContentType.YAML;
-        }
-        // CBOR logic similar to CBORFactory#hasCBORFormat
-        if (first == CBORConstants.BYTE_OBJECT_INDEFINITE && length > 1) {
-            return XContentType.CBOR;
-        }
-        if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_TAG, first) && length > 2) {
-            // Actually, specific "self-describe tag" is a very good indicator
-            if (first == (byte) 0xD9 && bytes[offset + 1] == (byte) 0xD9 && bytes[offset + 2] == (byte) 0xF7) {
-                return XContentType.CBOR;
-            }
-        }
-        // for small objects, some encoders just encode as major type object, we can safely
-        // say its CBOR since it doesn't contradict SMILE or JSON, and its a last resort
-        if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_OBJECT, first)) {
-            return XContentType.CBOR;
-        }
-
-        int jsonStart = 0;
-        // JSON may be preceded by UTF-8 BOM
-        if (length > 3 && first == (byte) 0xEF && bytes[offset + 1] == (byte) 0xBB && bytes[offset + 2] == (byte) 0xBF) {
-            jsonStart = 3;
-        }
-
-        // a last chance for JSON
-        for (int i = jsonStart; i < length; i++) {
-            byte b = bytes[offset + i];
-            if (b == '{') {
-                return XContentType.JSON;
-            }
-            if (Character.isWhitespace(b) == false) {
-                break;
-            }
-        }
-        return null;
+        return MediaTypeRegistry.contentBuilder(XContentType.CBOR);
     }
 }
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentType.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentType.java
index b0986d603ef23..9d1581a3a1517 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentType.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentType.java
@@ -32,18 +32,25 @@
 
 package org.opensearch.common.xcontent;
 
+import com.fasterxml.jackson.dataformat.cbor.CBORConstants;
+import com.fasterxml.jackson.dataformat.smile.SmileConstants;
+
 import org.opensearch.common.xcontent.cbor.CborXContent;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.smile.SmileXContent;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
-import java.util.Locale;
-import java.util.Objects;
+import java.io.IOException;
+import java.io.OutputStream;
 
 /**
- * The content type of {@link org.opensearch.common.xcontent.XContent}.
+ * The content type of {@link XContent}.
  */
-public enum XContentType {
+public enum XContentType implements MediaType {
 
     /**
      * A JSON based content type.
@@ -60,7 +67,7 @@ public String mediaType() {
         }
 
         @Override
-        public String shortName() {
+        public String subtype() {
             return "json";
         }
 
@@ -68,6 +75,26 @@ public String shortName() {
         public XContent xContent() {
             return JsonXContent.jsonXContent;
         }
+
+        @Override
+        public boolean detectedXContent(final byte[] bytes, int offset, int length) {
+            return bytes[offset] == '{';
+        }
+
+        @Override
+        public boolean detectedXContent(final CharSequence content, final int length) {
+            return content.charAt(0) == '{';
+        }
+
+        @Override
+        public XContentBuilder contentBuilder() throws IOException {
+            return JsonXContent.contentBuilder();
+        }
+
+        @Override
+        public XContentBuilder contentBuilder(final OutputStream os) throws IOException {
+            return new XContentBuilder(JsonXContent.jsonXContent, os);
+        }
     },
     /**
      * The jackson based smile binary format. Fast and compact binary format.
@@ -79,7 +106,7 @@ public String mediaTypeWithoutParameters() {
         }
 
         @Override
-        public String shortName() {
+        public String subtype() {
             return "smile";
         }
 
@@ -87,6 +114,32 @@ public String shortName() {
         public XContent xContent() {
             return SmileXContent.smileXContent;
         }
+
+        @Override
+        public boolean detectedXContent(final byte[] bytes, int offset, int length) {
+            return length > 2
+                && bytes[offset] == SmileConstants.HEADER_BYTE_1
+                && bytes[offset + 1] == SmileConstants.HEADER_BYTE_2
+                && bytes[offset + 2] == SmileConstants.HEADER_BYTE_3;
+        }
+
+        @Override
+        public boolean detectedXContent(final CharSequence content, final int length) {
+            return length > 2
+                && content.charAt(0) == SmileConstants.HEADER_BYTE_1
+                && content.charAt(1) == SmileConstants.HEADER_BYTE_2
+                && content.charAt(2) == SmileConstants.HEADER_BYTE_3;
+        }
+
+        @Override
+        public XContentBuilder contentBuilder() throws IOException {
+            return SmileXContent.contentBuilder();
+        }
+
+        @Override
+        public XContentBuilder contentBuilder(final OutputStream os) throws IOException {
+            return new XContentBuilder(SmileXContent.smileXContent, os);
+        }
     },
     /**
      * A YAML based content type.
@@ -98,7 +151,7 @@ public String mediaTypeWithoutParameters() {
         }
 
         @Override
-        public String shortName() {
+        public String subtype() {
             return "yaml";
         }
 
@@ -106,6 +159,26 @@ public String shortName() {
         public XContent xContent() {
             return YamlXContent.yamlXContent;
         }
+
+        @Override
+        public boolean detectedXContent(final byte[] bytes, int offset, int length) {
+            return length > 2 && bytes[offset] == '-' && bytes[offset + 1] == '-' && bytes[offset + 2] == '-';
+        }
+
+        @Override
+        public boolean detectedXContent(final CharSequence content, final int length) {
+            return length > 2 && content.charAt(0) == '-' && content.charAt(1) == '-' && content.charAt(2) == '-';
+        }
+
+        @Override
+        public XContentBuilder contentBuilder() throws IOException {
+            return YamlXContent.contentBuilder();
+        }
+
+        @Override
+        public XContentBuilder contentBuilder(final OutputStream os) throws IOException {
+            return new XContentBuilder(YamlXContent.yamlXContent, os);
+        }
     },
     /**
      * A CBOR based content type.
@@ -117,7 +190,7 @@ public String mediaTypeWithoutParameters() {
         }
 
         @Override
-        public String shortName() {
+        public String subtype() {
             return "cbor";
         }
 
@@ -125,74 +198,42 @@ public String shortName() {
         public XContent xContent() {
             return CborXContent.cborXContent;
         }
-    };
 
-    /**
-     * Accepts either a format string, which is equivalent to {@link XContentType#shortName()} or a media type that optionally has
-     * parameters and attempts to match the value to an {@link XContentType}. The comparisons are done in lower case format and this method
-     * also supports a wildcard accept for {@code application/*}. This method can be used to parse the {@code Accept} HTTP header or a
-     * format query string parameter. This method will return {@code null} if no match is found
-     */
-    public static XContentType fromMediaTypeOrFormat(String mediaType) {
-        if (mediaType == null) {
-            return null;
-        }
-
-        mediaType = removeVersionInMediaType(mediaType);
-        for (XContentType type : values()) {
-            if (isSameMediaTypeOrFormatAs(mediaType, type)) {
-                return type;
+        @Override
+        public boolean detectedXContent(final byte[] bytes, int offset, int length) {
+            // CBOR logic similar to CBORFactory#hasCBORFormat
+            if (bytes[offset] == CBORConstants.BYTE_OBJECT_INDEFINITE && length > 1) {
+                return true;
             }
+            if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_TAG, bytes[offset]) && length > 2) {
+                // Actually, specific "self-describe tag" is a very good indicator
+                if (bytes[offset] == (byte) 0xD9 && bytes[offset + 1] == (byte) 0xD9 && bytes[offset + 2] == (byte) 0xF7) {
+                    return true;
+                }
+            }
+            // for small objects, some encoders just encode as major type object, we can safely
+            // say its CBOR since it doesn't contradict SMILE or JSON, and its a last resort
+            if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_OBJECT, bytes[offset])) {
+                return true;
+            }
+            return false;
         }
-        final String lowercaseMediaType = mediaType.toLowerCase(Locale.ROOT);
-        if (lowercaseMediaType.startsWith("application/*")) {
-            return JSON;
-        }
-
-        return null;
-    }
 
-    /**
-     * Clients compatible with ES 7.x might start sending media types with versioned media type
-     * in a form of application/vnd.opensearch+json;compatible-with=7.
-     * This has to be removed in order to be used in 7.x server.
-     * The same client connecting using that media type will be able to communicate with ES 8 thanks to compatible API.
-     * @param mediaType - a media type used on Content-Type header, might contain versioned media type.
-     *
-     * @return a media type string without
-     */
-    private static String removeVersionInMediaType(String mediaType) {
-        if (mediaType.contains("vnd.opensearch")) {
-            return mediaType.replaceAll("vnd.opensearch\\+", "").replaceAll("\\s*;\\s*compatible-with=\\d+", "");
+        @Override
+        public boolean detectedXContent(final CharSequence content, final int length) {
+            return false;
         }
-        return mediaType;
-    }
 
-    /**
-     * Attempts to match the given media type with the known {@link XContentType} values. This match is done in a case-insensitive manner.
-     * The provided media type should not include any parameters. This method is suitable for parsing part of the {@code Content-Type}
-     * HTTP header. This method will return {@code null} if no match is found
-     */
-    public static XContentType fromMediaType(String mediaType) {
-        final String lowercaseMediaType = Objects.requireNonNull(mediaType, "mediaType cannot be null").toLowerCase(Locale.ROOT);
-        for (XContentType type : values()) {
-            if (type.mediaTypeWithoutParameters().equals(lowercaseMediaType)) {
-                return type;
-            }
-        }
-        // we also support newline delimited JSON: http://specs.okfnlabs.org/ndjson/
-        if (lowercaseMediaType.toLowerCase(Locale.ROOT).equals("application/x-ndjson")) {
-            return XContentType.JSON;
+        @Override
+        public XContentBuilder contentBuilder() throws IOException {
+            return CborXContent.contentBuilder();
         }
 
-        return null;
-    }
-
-    private static boolean isSameMediaTypeOrFormatAs(String stringType, XContentType type) {
-        return type.mediaTypeWithoutParameters().equalsIgnoreCase(stringType)
-            || stringType.toLowerCase(Locale.ROOT).startsWith(type.mediaTypeWithoutParameters().toLowerCase(Locale.ROOT) + ";")
-            || type.shortName().equalsIgnoreCase(stringType);
-    }
+        @Override
+        public XContentBuilder contentBuilder(final OutputStream os) throws IOException {
+            return new XContentBuilder(CborXContent.cborXContent, os);
+        }
+    };
 
     private int index;
 
@@ -204,14 +245,18 @@ public int index() {
         return index;
     }
 
-    public String mediaType() {
-        return mediaTypeWithoutParameters();
+    @Override
+    public String type() {
+        return "application";
     }
 
-    public abstract String shortName();
-
-    public abstract XContent xContent();
-
-    public abstract String mediaTypeWithoutParameters();
+    @Override
+    public String format() {
+        return subtype();
+    }
 
+    @Override
+    public void writeTo(StreamOutput output) throws IOException {
+        output.writeString(this.mediaType());
+    }
 }
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentUtils.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentUtils.java
index 6bb6c9ad09932..d0f2937807584 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentUtils.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/XContentUtils.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.common.xcontent;
 
+import org.opensearch.core.xcontent.XContentParser;
+
 import java.io.IOException;
 
 public final class XContentUtils {
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContent.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContent.java
index 674b6566bdec0..cf6123dba57cd 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContent.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContent.java
@@ -35,15 +35,20 @@
 import com.fasterxml.jackson.core.JsonEncoding;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.core.StreamReadFeature;
+import com.fasterxml.jackson.core.StreamWriteFeature;
 import com.fasterxml.jackson.dataformat.cbor.CBORFactory;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
+
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -55,6 +60,11 @@
  * A CBOR based content implementation using Jackson.
  */
 public class CborXContent implements XContent {
+    public static final int DEFAULT_MAX_STRING_LEN = Integer.parseInt(
+        System.getProperty("opensearch.xcontent.string.length.max", Integer.toString(Integer.MAX_VALUE) /* no limit */)
+    );
+
+    public static final boolean USE_FAST_DOUBLE_WRITER = Boolean.getBoolean("opensearch.xcontent.use_fast_double_writer");
 
     public static XContentBuilder contentBuilder() throws IOException {
         return XContentBuilder.builder(cborXContent);
@@ -69,13 +79,16 @@ public static XContentBuilder contentBuilder() throws IOException {
         // Do not automatically close unclosed objects/arrays in com.fasterxml.jackson.dataformat.cbor.CBORGenerator#close() method
         cborFactory.configure(JsonGenerator.Feature.AUTO_CLOSE_JSON_CONTENT, false);
         cborFactory.configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true);
+        cborFactory.setStreamReadConstraints(StreamReadConstraints.builder().maxStringLength(DEFAULT_MAX_STRING_LEN).build());
+        cborFactory.configure(StreamReadFeature.USE_FAST_DOUBLE_PARSER.mappedFeature(), true);
+        cborFactory.configure(StreamWriteFeature.USE_FAST_DOUBLE_WRITER.mappedFeature(), USE_FAST_DOUBLE_WRITER);
         cborXContent = new CborXContent();
     }
 
     private CborXContent() {}
 
     @Override
-    public XContentType type() {
+    public MediaType mediaType() {
         return XContentType.CBOR;
     }
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentGenerator.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentGenerator.java
index 2dba887c664b6..1c13ebd3981a9 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentGenerator.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentGenerator.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.xcontent.cbor;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentGenerator;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentParser.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentParser.java
index d36273a46df89..4abc9650c4bf6 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentParser.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/cbor/CborXContentParser.java
@@ -33,10 +33,11 @@
 package org.opensearch.common.xcontent.cbor;
 
 import com.fasterxml.jackson.core.JsonParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 
 public class CborXContentParser extends JsonXContentParser {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContent.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContent.java
index a7872904b1126..3cd8af551ba81 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContent.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContent.java
@@ -36,13 +36,18 @@
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.core.StreamReadFeature;
+import com.fasterxml.jackson.core.StreamWriteFeature;
+
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -54,6 +59,11 @@
  * A JSON based content implementation using Jackson.
  */
 public class JsonXContent implements XContent {
+    public static final int DEFAULT_MAX_STRING_LEN = Integer.parseInt(
+        System.getProperty("opensearch.xcontent.string.length.max", Integer.toString(Integer.MAX_VALUE) /* no limit */)
+    );
+
+    public static final boolean USE_FAST_DOUBLE_WRITER = Boolean.getBoolean("opensearch.xcontent.use_fast_double_writer");
 
     public static XContentBuilder contentBuilder() throws IOException {
         return XContentBuilder.builder(jsonXContent);
@@ -71,13 +81,16 @@ public static XContentBuilder contentBuilder() throws IOException {
         // Do not automatically close unclosed objects/arrays in com.fasterxml.jackson.core.json.UTF8JsonGenerator#close() method
         jsonFactory.configure(JsonGenerator.Feature.AUTO_CLOSE_JSON_CONTENT, false);
         jsonFactory.configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true);
+        jsonFactory.setStreamReadConstraints(StreamReadConstraints.builder().maxStringLength(DEFAULT_MAX_STRING_LEN).build());
+        jsonFactory.configure(StreamReadFeature.USE_FAST_DOUBLE_PARSER.mappedFeature(), true);
+        jsonFactory.configure(StreamWriteFeature.USE_FAST_DOUBLE_WRITER.mappedFeature(), USE_FAST_DOUBLE_WRITER);
         jsonXContent = new JsonXContent();
     }
 
     private JsonXContent() {}
 
     @Override
-    public XContentType type() {
+    public MediaType mediaType() {
         return XContentType.JSON;
     }
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentGenerator.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentGenerator.java
index b972f52c57201..3f8493d7a4f14 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentGenerator.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentGenerator.java
@@ -41,15 +41,17 @@
 import com.fasterxml.jackson.core.util.DefaultIndenter;
 import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
 import com.fasterxml.jackson.core.util.JsonGeneratorDelegate;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
+
+import org.opensearch.common.util.io.Streams;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.common.xcontent.support.filtering.FilterPathBasedFilter;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.filtering.FilterPathBasedFilter;
 
 import java.io.BufferedInputStream;
 import java.io.IOException;
@@ -338,19 +340,22 @@ public void writeRawField(String name, InputStream content) throws IOException {
             // needed for the XContentFactory.xContentType call
             content = new BufferedInputStream(content);
         }
-        XContentType contentType = XContentFactory.xContentType(content);
+        MediaType contentType = MediaTypeRegistry.xContentType(content);
         if (contentType == null) {
             throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
         }
         writeRawField(name, content, contentType);
     }
 
+    /**
+     * Writes a raw field with the value taken from the bytes in the stream
+     */
     @Override
-    public void writeRawField(String name, InputStream content, XContentType contentType) throws IOException {
-        if (mayWriteRawData(contentType) == false) {
+    public void writeRawField(String name, InputStream content, MediaType mediaType) throws IOException {
+        if (mayWriteRawData(mediaType) == false) {
             // EMPTY is safe here because we never call namedObject when writing raw data
             try (
-                XContentParser parser = XContentFactory.xContent(contentType)
+                XContentParser parser = mediaType.xContent()
                     // It's okay to pass the throwing deprecation handler
                     // because we should not be writing raw fields when
                     // generating JSON
@@ -368,10 +373,13 @@ public void writeRawField(String name, InputStream content, XContentType content
         }
     }
 
+    /**
+     * Writes the raw value to the stream
+     */
     @Override
-    public void writeRawValue(InputStream stream, XContentType xContentType) throws IOException {
-        if (mayWriteRawData(xContentType) == false) {
-            copyRawValue(stream, xContentType.xContent());
+    public void writeRawValue(InputStream stream, MediaType mediaType) throws IOException {
+        if (mayWriteRawData(mediaType) == false) {
+            copyRawValue(stream, mediaType.xContent());
         } else {
             if (generator.getOutputContext().getCurrentName() != null) {
                 // If we've just started a field we'll need to add the separator
@@ -383,6 +391,12 @@ public void writeRawValue(InputStream stream, XContentType xContentType) throws
         }
     }
 
+    /**
+     * possibly copy the whole structure to correctly filter
+     *
+     * @deprecated use {@link #mayWriteRawData(MediaType)} instead
+     */
+    @Deprecated
     private boolean mayWriteRawData(XContentType contentType) {
         // When the current generator is filtered (ie filter != null)
         // or the content is in a different format than the current generator,
@@ -391,6 +405,17 @@ private boolean mayWriteRawData(XContentType contentType) {
         return supportsRawWrites() && isFiltered() == false && contentType == contentType() && prettyPrint == false;
     }
 
+    /**
+     * possibly copy the whole structure to correctly filter
+     */
+    private boolean mayWriteRawData(MediaType contentType) {
+        // When the current generator is filtered (ie filter != null)
+        // or the content is in a different format than the current generator,
+        // we need to copy the whole structure so that it will be correctly
+        // filtered or converted
+        return supportsRawWrites() && isFiltered() == false && contentType == contentType() && prettyPrint == false;
+    }
+
     /** Whether this generator supports writing raw data directly */
     protected boolean supportsRawWrites() {
         return true;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentParser.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentParser.java
index 8639e50214d85..ed830c6b7bfa3 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentParser.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/json/JsonXContentParser.java
@@ -35,14 +35,16 @@
 import com.fasterxml.jackson.core.JsonLocation;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonToken;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentLocation;
+
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.common.xcontent.support.AbstractXContentParser;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.xcontent.AbstractXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentLocation;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.nio.CharBuffer;
 
 public class JsonXContentParser extends AbstractXContentParser {
@@ -188,6 +190,15 @@ public double doDoubleValue() throws IOException {
         return parser.getDoubleValue();
     }
 
+    @Override
+    public BigInteger doBigIntegerValue() throws IOException {
+        if (parser.getCurrentToken() == JsonToken.VALUE_NUMBER_FLOAT) {
+            return parser.getDecimalValue().toBigInteger();
+        } else {
+            return parser.getBigIntegerValue();
+        }
+    }
+
     @Override
     public byte[] binaryValue() throws IOException {
         return parser.getBinaryValue();
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContent.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContent.java
index 82925c5f84f9c..b28192d0ab44f 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContent.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContent.java
@@ -35,15 +35,20 @@
 import com.fasterxml.jackson.core.JsonEncoding;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.core.StreamReadFeature;
+import com.fasterxml.jackson.core.StreamWriteFeature;
 import com.fasterxml.jackson.dataformat.smile.SmileFactory;
 import com.fasterxml.jackson.dataformat.smile.SmileGenerator;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
+
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -55,6 +60,11 @@
  * A Smile based content implementation using Jackson.
  */
 public class SmileXContent implements XContent {
+    public static final int DEFAULT_MAX_STRING_LEN = Integer.parseInt(
+        System.getProperty("opensearch.xcontent.string.length.max", Integer.toString(Integer.MAX_VALUE) /* no limit */)
+    );
+
+    public static final boolean USE_FAST_DOUBLE_WRITER = Boolean.getBoolean("opensearch.xcontent.use_fast_double_writer");
 
     public static XContentBuilder contentBuilder() throws IOException {
         return XContentBuilder.builder(smileXContent);
@@ -71,13 +81,16 @@ public static XContentBuilder contentBuilder() throws IOException {
         // Do not automatically close unclosed objects/arrays in com.fasterxml.jackson.dataformat.smile.SmileGenerator#close() method
         smileFactory.configure(JsonGenerator.Feature.AUTO_CLOSE_JSON_CONTENT, false);
         smileFactory.configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true);
+        smileFactory.setStreamReadConstraints(StreamReadConstraints.builder().maxStringLength(DEFAULT_MAX_STRING_LEN).build());
+        smileFactory.configure(StreamReadFeature.USE_FAST_DOUBLE_PARSER.mappedFeature(), true);
+        smileFactory.configure(StreamWriteFeature.USE_FAST_DOUBLE_WRITER.mappedFeature(), USE_FAST_DOUBLE_WRITER);
         smileXContent = new SmileXContent();
     }
 
     private SmileXContent() {}
 
     @Override
-    public XContentType type() {
+    public MediaType mediaType() {
         return XContentType.SMILE;
     }
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentGenerator.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentGenerator.java
index b7ba56bdb01ea..0315e9a77272f 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentGenerator.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentGenerator.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.xcontent.smile;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentGenerator;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentParser.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentParser.java
index 84c4d1a2112cd..ade265798b5a4 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentParser.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/smile/SmileXContentParser.java
@@ -33,10 +33,11 @@
 package org.opensearch.common.xcontent.smile;
 
 import com.fasterxml.jackson.core.JsonParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 
 public class SmileXContentParser extends JsonXContentParser {
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/XContentProvider.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/XContentProvider.java
new file mode 100644
index 0000000000000..af5ab67507b81
--- /dev/null
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/XContentProvider.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.xcontent.spi;
+
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.spi.MediaTypeProvider;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Media Type implementations provided by xcontent library
+ *
+ * @opensearch.internal
+ */
+public class XContentProvider implements MediaTypeProvider {
+    /** Returns the concrete {@link MediaType} provided by the xcontent library */
+    @Override
+    public List<MediaType> getMediaTypes() {
+        return List.of(XContentType.values());
+    }
+
+    /** Returns the additional {@link MediaType} aliases provided by the xcontent library */
+    @Override
+    public Map<String, MediaType> getAdditionalMediaTypes() {
+        return Map.of("application/*", XContentType.JSON, "application/x-ndjson", XContentType.JSON);
+    }
+}
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/package-info.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/package-info.java
new file mode 100644
index 0000000000000..c265021f12763
--- /dev/null
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/spi/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** SPI implementation for the xcontent library */
+package org.opensearch.common.xcontent.spi;
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContent.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContent.java
index 8ebdeca71c0ce..84e19b226cd36 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContent.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContent.java
@@ -34,14 +34,19 @@
 
 import com.fasterxml.jackson.core.JsonEncoding;
 import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.core.StreamReadFeature;
+import com.fasterxml.jackson.core.StreamWriteFeature;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
+
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -53,6 +58,11 @@
  * A YAML based content implementation using Jackson.
  */
 public class YamlXContent implements XContent {
+    public static final int DEFAULT_MAX_STRING_LEN = Integer.parseInt(
+        System.getProperty("opensearch.xcontent.string.length.max", Integer.toString(Integer.MAX_VALUE) /* no limit */)
+    );
+
+    public static final boolean USE_FAST_DOUBLE_WRITER = Boolean.getBoolean("opensearch.xcontent.use_fast_double_writer");
 
     public static XContentBuilder contentBuilder() throws IOException {
         return XContentBuilder.builder(yamlXContent);
@@ -64,13 +74,16 @@ public static XContentBuilder contentBuilder() throws IOException {
     static {
         yamlFactory = new YAMLFactory();
         yamlFactory.configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true);
+        yamlFactory.setStreamReadConstraints(StreamReadConstraints.builder().maxStringLength(DEFAULT_MAX_STRING_LEN).build());
+        yamlFactory.configure(StreamReadFeature.USE_FAST_DOUBLE_PARSER.mappedFeature(), true);
+        yamlFactory.configure(StreamWriteFeature.USE_FAST_DOUBLE_WRITER.mappedFeature(), USE_FAST_DOUBLE_WRITER);
         yamlXContent = new YamlXContent();
     }
 
     private YamlXContent() {}
 
     @Override
-    public XContentType type() {
+    public MediaType mediaType() {
         return XContentType.YAML;
     }
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentGenerator.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentGenerator.java
index 5dd85afdb9c01..ddc9f5365c22b 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentGenerator.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentGenerator.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.xcontent.yaml;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentGenerator;
 
diff --git a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentParser.java b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentParser.java
index cc523dc6f978d..5fabe58cca919 100644
--- a/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentParser.java
+++ b/libs/x-content/src/main/java/org/opensearch/common/xcontent/yaml/YamlXContentParser.java
@@ -33,10 +33,11 @@
 package org.opensearch.common.xcontent.yaml;
 
 import com.fasterxml.jackson.core.JsonParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 
 public class YamlXContentParser extends JsonXContentParser {
 
diff --git a/libs/x-content/src/main/resources/META-INF/services/org.opensearch.core.xcontent.spi.MediaTypeProvider b/libs/x-content/src/main/resources/META-INF/services/org.opensearch.core.xcontent.spi.MediaTypeProvider
new file mode 100644
index 0000000000000..ce3fab93087dd
--- /dev/null
+++ b/libs/x-content/src/main/resources/META-INF/services/org.opensearch.core.xcontent.spi.MediaTypeProvider
@@ -0,0 +1,9 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+
+org.opensearch.common.xcontent.spi.XContentProvider
diff --git a/libs/x-content/src/test/java/org/opensearch/common/ParseFieldTests.java b/libs/x-content/src/test/java/org/opensearch/common/ParseFieldTests.java
index d0d3c1236241b..a5cb14cdc8393 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/ParseFieldTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/ParseFieldTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.common;
 
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.core.ParseField;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.CoreMatchers.is;
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ConstructingObjectParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ConstructingObjectParserTests.java
index d555f3c60bd75..d27289d3b1359 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ConstructingObjectParserTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ConstructingObjectParserTests.java
@@ -34,9 +34,17 @@
 
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.xcontent.ObjectParserTests.NamedObject;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matcher;
 
@@ -46,8 +54,8 @@
 import java.util.List;
 
 import static java.util.Collections.unmodifiableList;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/InstantiatingObjectParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/InstantiatingObjectParserTests.java
index 3c34453a636d1..4e509951462b2 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/InstantiatingObjectParserTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/InstantiatingObjectParserTests.java
@@ -32,14 +32,17 @@
 
 package org.opensearch.common.xcontent;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.InstantiatingObjectParser;
+import org.opensearch.core.xcontent.ParserConstructor;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/MapXContentParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/MapXContentParserTests.java
index 380af6ff2648f..ed6d38289ef6a 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/MapXContentParserTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/MapXContentParserTests.java
@@ -33,8 +33,10 @@
 package org.opensearch.common.xcontent;
 
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.support.MapXContentParser;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/MediaTypeParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/MediaTypeParserTests.java
new file mode 100644
index 0000000000000..64d36f0a8b78f
--- /dev/null
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/MediaTypeParserTests.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.xcontent;
+
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Collections;
+import java.util.Map;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+
+public class MediaTypeParserTests extends OpenSearchTestCase {
+
+    public void testJsonWithParameters() throws Exception {
+        String mediaType = "application/json";
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType).getParameters(), equalTo(Collections.emptyMap()));
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType + ";").getParameters(), equalTo(Collections.emptyMap()));
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType + "; charset=UTF-8").getParameters(), equalTo(Map.of("charset", "utf-8")));
+        assertThat(
+            MediaTypeRegistry.parseMediaType(mediaType + "; custom=123;charset=UTF-8").getParameters(),
+            equalTo(Map.of("charset", "utf-8", "custom", "123"))
+        );
+    }
+
+    public void testWhiteSpaceInTypeSubtype() {
+        String mediaType = " application/json ";
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType).getMediaType(), equalTo(XContentType.JSON));
+
+        assertThat(
+            MediaTypeRegistry.parseMediaType(mediaType + "; custom=123; charset=UTF-8").getParameters(),
+            equalTo(Map.of("charset", "utf-8", "custom", "123"))
+        );
+        assertThat(
+            MediaTypeRegistry.parseMediaType(mediaType + "; custom=123;\n charset=UTF-8").getParameters(),
+            equalTo(Map.of("charset", "utf-8", "custom", "123"))
+        );
+
+        mediaType = " application / json ";
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType), is(nullValue()));
+    }
+
+    public void testInvalidParameters() {
+        String mediaType = "application/json";
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType + "; keyvalueNoEqualsSign"), is(nullValue()));
+
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType + "; key = value"), is(nullValue()));
+        assertThat(MediaTypeRegistry.parseMediaType(mediaType + "; key="), is(nullValue()));
+    }
+}
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectParserTests.java
index 7ac11e05f741c..5f87a17007fb5 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectParserTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectParserTests.java
@@ -32,11 +32,19 @@
 package org.opensearch.common.xcontent;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayOutputStream;
@@ -387,7 +395,7 @@ public void testAllVariants() throws IOException {
         double expectedNullableDouble;
         int expectedNullableInt;
 
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
         builder.startObject();
         builder.field("int_field", randomBoolean() ? "1" : 1);
         if (randomBoolean()) {
@@ -441,7 +449,7 @@ public void testAllVariants() throws IOException {
         }
         builder.field("string_or_null", nullValue ? null : "5");
         builder.endObject();
-        XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder));
+        XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString());
         class TestStruct {
             int int_field;
             int nullableIntField;
@@ -639,7 +647,7 @@ public void testParseNamedObjectsInOrderNotSupported() throws IOException {
     }
 
     public void testIgnoreUnknownFields() throws IOException {
-        XContentBuilder b = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder b = MediaTypeRegistry.JSON.contentBuilder();
         b.startObject();
         {
             b.field("test", "foo");
@@ -661,7 +669,7 @@ class TestStruct {
     }
 
     public void testIgnoreUnknownObjects() throws IOException {
-        XContentBuilder b = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder b = MediaTypeRegistry.JSON.contentBuilder();
         b.startObject();
         {
             b.field("test", "foo");
@@ -687,7 +695,7 @@ class TestStruct {
     }
 
     public void testIgnoreUnknownArrays() throws IOException {
-        XContentBuilder b = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder b = MediaTypeRegistry.JSON.contentBuilder();
         b.startObject();
         {
             b.field("test", "foo");
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectPathTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectPathTests.java
index f6731aa128da5..a400c02092a63 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectPathTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/ObjectPathTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.common.xcontent;
 
+import org.opensearch.core.xcontent.ObjectPath;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/SimpleStruct.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/SimpleStruct.java
index acc6dc4c8aa3c..1d2a66ea1f78f 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/SimpleStruct.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/SimpleStruct.java
@@ -32,13 +32,17 @@
 
 package org.opensearch.common.xcontent;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Simple structure with 3 fields: int, double and String.
@@ -101,6 +105,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(XContentType.JSON, this);
     }
 }
diff --git a/libs/x-content/src/test/java/org/opensearch/common/xcontent/XContentParserTests.java b/libs/x-content/src/test/java/org/opensearch/common/xcontent/XContentParserTests.java
index 33dc7f4ba25b5..44a4fe4143d05 100644
--- a/libs/x-content/src/test/java/org/opensearch/common/xcontent/XContentParserTests.java
+++ b/libs/x-content/src/test/java/org/opensearch/common/xcontent/XContentParserTests.java
@@ -33,10 +33,17 @@
 package org.opensearch.common.xcontent;
 
 import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.dataformat.yaml.JacksonYAMLParseException;
+
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.xcontent.cbor.CborXContent;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.common.xcontent.smile.SmileXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentSubParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -46,6 +53,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Supplier;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
@@ -53,6 +61,7 @@
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasLength;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.in;
 import static org.hamcrest.Matchers.instanceOf;
@@ -60,6 +69,72 @@
 import static org.junit.internal.matchers.ThrowableMessageMatcher.hasMessage;
 
 public class XContentParserTests extends OpenSearchTestCase {
+    private static final Map<XContentType, Supplier<String>> GENERATORS = Map.of(
+        XContentType.JSON,
+        () -> randomAlphaOfLengthBetween(1, JsonXContent.DEFAULT_MAX_STRING_LEN / 10), /* limit to ~200Mb */
+        XContentType.CBOR,
+        () -> randomAlphaOfLengthBetween(1, CborXContent.DEFAULT_MAX_STRING_LEN / 10), /* limit to ~200Mb */
+        XContentType.SMILE,
+        () -> randomAlphaOfLengthBetween(1, SmileXContent.DEFAULT_MAX_STRING_LEN / 10), /* limit to ~200Mb */
+        /* YAML parser limitation */
+        XContentType.YAML,
+        () -> randomAlphaOfLengthBetween(1, 3140000)
+    );
+
+    public void testStringOffLimit() throws IOException {
+        final String field = randomAlphaOfLengthBetween(1, 5);
+        final String value = randomRealisticUnicodeOfCodepointLength(3145730);
+
+        try (XContentBuilder builder = XContentBuilder.builder(XContentType.YAML.xContent())) {
+            builder.startObject();
+            if (randomBoolean()) {
+                builder.field(field, value);
+            } else {
+                builder.field(field).value(value);
+            }
+            builder.endObject();
+
+            try (XContentParser parser = createParser(XContentType.YAML.xContent(), BytesReference.bytes(builder))) {
+                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
+                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
+                assertEquals(field, parser.currentName());
+                assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
+                assertThrows(JacksonYAMLParseException.class, () -> parser.nextToken());
+            }
+        }
+    }
+
+    public void testString() throws IOException {
+        final XContentType xContentType = randomFrom(XContentType.values());
+
+        final String field = randomAlphaOfLengthBetween(1, 5);
+        final String value = GENERATORS.get(xContentType).get();
+
+        try (XContentBuilder builder = XContentBuilder.builder(xContentType.xContent())) {
+            builder.startObject();
+            if (randomBoolean()) {
+                builder.field(field, value);
+            } else {
+                builder.field(field).value(value);
+            }
+            builder.endObject();
+
+            final String text;
+            try (XContentParser parser = createParser(xContentType.xContent(), BytesReference.bytes(builder))) {
+                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
+                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
+                assertEquals(field, parser.currentName());
+                assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
+
+                text = parser.text();
+
+                assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
+                assertNull(parser.nextToken());
+            }
+
+            assertThat(text, hasLength(value.length()));
+        }
+    }
 
     public void testFloat() throws IOException {
         final XContentType xContentType = randomFrom(XContentType.values());
@@ -271,7 +346,7 @@ public void testReadBooleans() throws IOException {
     public void testEmptyList() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().startArray("some_array").endArray().endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
             assertEquals("some_array", parser.currentName());
@@ -293,7 +368,7 @@ public void testSimpleList() throws IOException {
             .endArray()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
             assertEquals("some_array", parser.currentName());
@@ -321,7 +396,7 @@ public void testNestedList() throws IOException {
             .endArray()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
             assertEquals("some_array", parser.currentName());
@@ -345,7 +420,7 @@ public void testNestedMapInList() throws IOException {
             .endArray()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
             assertEquals("some_array", parser.currentName());
@@ -421,7 +496,7 @@ public void testSubParserObject() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
         int numberOfTokens;
         numberOfTokens = generateRandomObjectForMarking(builder);
-        String content = Strings.toString(builder);
+        String content = builder.toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, content)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
@@ -469,7 +544,7 @@ public void testSubParserArray() throws IOException {
         builder.endArray();
         builder.endObject();
 
-        String content = Strings.toString(builder);
+        String content = builder.toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, content)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
@@ -502,7 +577,7 @@ public void testSubParserArray() throws IOException {
     public void testCreateSubParserAtAWrongPlace() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
         generateRandomObjectForMarking(builder);
-        String content = Strings.toString(builder);
+        String content = builder.toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, content)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
@@ -516,7 +591,7 @@ public void testCreateSubParserAtAWrongPlace() throws IOException {
     public void testCreateRootSubParser() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
         int numberOfTokens = generateRandomObjectForMarking(builder);
-        String content = Strings.toString(builder);
+        String content = builder.toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, content)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/spi/MatrixStatsNamedXContentProvider.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/spi/MatrixStatsNamedXContentProvider.java
index fc63bf1fa537c..302c724324159 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/spi/MatrixStatsNamedXContentProvider.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/spi/MatrixStatsNamedXContentProvider.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.matrix.spi;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.plugins.spi.NamedXContentProvider;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStats.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStats.java
index 42c6d106a414e..3099ba3c6aa19 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStats.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStats.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.matrix.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 
 import java.io.IOException;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregationBuilder.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregationBuilder.java
index 2f73780fcb4af..f757968bd86f7 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregationBuilder.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregationBuilder.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.matrix.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.AggregationBuilder;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregator.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregator.java
index 142e7ca3dbc15..7e48d659e0bbc 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregator.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregator.java
@@ -43,9 +43,9 @@
 import org.opensearch.search.aggregations.LeafBucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollectorBase;
 import org.opensearch.search.aggregations.metrics.MetricsAggregator;
+import org.opensearch.search.aggregations.support.ArrayValuesSource;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.internal.SearchContext;
-import org.opensearch.search.aggregations.support.ArrayValuesSource;
 
 import java.io.IOException;
 import java.util.Map;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorFactory.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorFactory.java
index f7ab0db3c9607..24f74f3859157 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorFactory.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorFactory.java
@@ -89,4 +89,9 @@ protected Aggregator doCreateInternal(
         }
         return new MatrixStatsAggregator(name, typedValuesSources, searchContext, parent, multiValueMode, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsParser.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsParser.java
index 9ee1851a02a1c..a62033d93e640 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsParser.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsParser.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.search.aggregations.matrix.stats;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.MultiValueMode;
-import org.opensearch.search.aggregations.support.ValueType;
-import org.opensearch.search.aggregations.support.ValuesSourceType;
 import org.opensearch.search.aggregations.support.ArrayValuesSourceAggregationBuilder;
 import org.opensearch.search.aggregations.support.ArrayValuesSourceParser;
+import org.opensearch.search.aggregations.support.ValueType;
+import org.opensearch.search.aggregations.support.ValuesSourceType;
 
 import java.io.IOException;
 import java.util.Map;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsResults.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsResults.java
index 87eb58ab3427a..6e04efbf6689c 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsResults.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsResults.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.matrix.stats;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/ParsedMatrixStats.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/ParsedMatrixStats.java
index c3049992b6c0e..868d070bb6065 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/ParsedMatrixStats.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/ParsedMatrixStats.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.matrix.stats;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/RunningStats.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/RunningStats.java
index cad0011602f67..de67cc2930652 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/RunningStats.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/matrix/stats/RunningStats.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.matrix.stats;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceAggregationBuilder.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceAggregationBuilder.java
index bea838994fa2c..102188deb91b5 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceAggregationBuilder.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceAggregationBuilder.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
 import org.opensearch.search.aggregations.AggregationInitializationException;
diff --git a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceParser.java b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceParser.java
index 0c7da3bdec298..855e1ca8e92ec 100644
--- a/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceParser.java
+++ b/modules/aggs-matrix-stats/src/main/java/org/opensearch/search/aggregations/support/ArrayValuesSourceParser.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.AggregationBuilder.CommonFields;
 import org.opensearch.search.aggregations.Aggregator;
diff --git a/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStatsTests.java b/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStatsTests.java
index e523c77e0786f..3e129bdb8a93c 100644
--- a/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStatsTests.java
+++ b/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/InternalMatrixStatsTests.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.search.aggregations.matrix.stats;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.aggregations.Aggregation;
diff --git a/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorTests.java b/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorTests.java
index da3228829816b..863e4e0e14c0a 100644
--- a/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorTests.java
+++ b/modules/aggs-matrix-stats/src/test/java/org/opensearch/search/aggregations/matrix/stats/MatrixStatsAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/modules/aggs-matrix-stats/src/yamlRestTest/java/org/opensearch/search/aggregations/matrix/MatrixStatsClientYamlTestSuiteIT.java b/modules/aggs-matrix-stats/src/yamlRestTest/java/org/opensearch/search/aggregations/matrix/MatrixStatsClientYamlTestSuiteIT.java
index 4aea2a210c2b4..b0d9681339652 100644
--- a/modules/aggs-matrix-stats/src/yamlRestTest/java/org/opensearch/search/aggregations/matrix/MatrixStatsClientYamlTestSuiteIT.java
+++ b/modules/aggs-matrix-stats/src/yamlRestTest/java/org/opensearch/search/aggregations/matrix/MatrixStatsClientYamlTestSuiteIT.java
@@ -33,6 +33,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/modules/aggs-matrix-stats/src/yamlRestTest/resources/rest-api-spec/test/stats/10_basic.yml b/modules/aggs-matrix-stats/src/yamlRestTest/resources/rest-api-spec/test/stats/10_basic.yml
index 2416d2b2b3141..b983a3960c64e 100644
--- a/modules/aggs-matrix-stats/src/yamlRestTest/resources/rest-api-spec/test/stats/10_basic.yml
+++ b/modules/aggs-matrix-stats/src/yamlRestTest/resources/rest-api-spec/test/stats/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: aggs-matrix-stats } }
+    - contains:  { nodes.$cluster_manager.modules: { name: aggs-matrix-stats } }
diff --git a/modules/analysis-common/src/internalClusterTest/java/org/opensearch/analysis/common/QueryStringWithAnalyzersIT.java b/modules/analysis-common/src/internalClusterTest/java/org/opensearch/analysis/common/QueryStringWithAnalyzersIT.java
index 8c2f83bf83d85..7b1db7d648ebd 100644
--- a/modules/analysis-common/src/internalClusterTest/java/org/opensearch/analysis/common/QueryStringWithAnalyzersIT.java
+++ b/modules/analysis-common/src/internalClusterTest/java/org/opensearch/analysis/common/QueryStringWithAnalyzersIT.java
@@ -32,20 +32,42 @@
 
 package org.opensearch.analysis.common;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.Operator;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
 
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 
-public class QueryStringWithAnalyzersIT extends OpenSearchIntegTestCase {
+public class QueryStringWithAnalyzersIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public QueryStringWithAnalyzersIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(CommonAnalysisPlugin.class);
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/ASCIIFoldingTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/ASCIIFoldingTokenFilterFactory.java
index b2eca8a601294..dc187de86ee19 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/ASCIIFoldingTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/ASCIIFoldingTokenFilterFactory.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.ParseField;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/BrazilianStemTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/BrazilianStemTokenFilterFactory.java
index 83e3cff1ddeda..8fbcb3fcd8215 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/BrazilianStemTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/BrazilianStemTokenFilterFactory.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.analysis.common;
 
+import org.apache.lucene.analysis.CharArraySet;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.br.BrazilianStemFilter;
 import org.apache.lucene.analysis.miscellaneous.SetKeywordMarkerFilter;
-import org.apache.lucene.analysis.CharArraySet;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisPlugin.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisPlugin.java
index c69917ed52be8..ec01f71da58e4 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisPlugin.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisPlugin.java
@@ -89,6 +89,7 @@
 import org.apache.lucene.analysis.lt.LithuanianAnalyzer;
 import org.apache.lucene.analysis.lv.LatvianAnalyzer;
 import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
+import org.apache.lucene.analysis.miscellaneous.DelimitedTermFrequencyTokenFilter;
 import org.apache.lucene.analysis.miscellaneous.DisableGraphAttribute;
 import org.apache.lucene.analysis.miscellaneous.KeywordRepeatFilter;
 import org.apache.lucene.analysis.miscellaneous.LengthFilter;
@@ -123,16 +124,16 @@
 import org.apache.lucene.analysis.tr.ApostropheFilter;
 import org.apache.lucene.analysis.tr.TurkishAnalyzer;
 import org.apache.lucene.analysis.util.ElisionFilter;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexSettings;
@@ -154,8 +155,6 @@
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.watcher.ResourceWatcherService;
-import org.tartarus.snowball.ext.DutchStemmer;
-import org.tartarus.snowball.ext.FrenchStemmer;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -165,6 +164,9 @@
 import java.util.TreeMap;
 import java.util.function.Supplier;
 
+import org.tartarus.snowball.ext.DutchStemmer;
+import org.tartarus.snowball.ext.FrenchStemmer;
+
 import static org.opensearch.plugins.AnalysisPlugin.requiresAnalysisSettings;
 
 public class CommonAnalysisPlugin extends Plugin implements AnalysisPlugin, ScriptPlugin {
@@ -264,6 +266,7 @@ public Map<String, AnalysisProvider<TokenFilterFactory>> getTokenFilters() {
         );
         filters.put("decimal_digit", DecimalDigitFilterFactory::new);
         filters.put("delimited_payload", DelimitedPayloadTokenFilterFactory::new);
+        filters.put("delimited_term_freq", DelimitedTermFrequencyTokenFilterFactory::new);
         filters.put("dictionary_decompounder", requiresAnalysisSettings(DictionaryCompoundWordTokenFilterFactory::new));
         filters.put("dutch_stem", DutchStemTokenFilterFactory::new);
         filters.put("edge_ngram", EdgeNGramTokenFilterFactory::new);
@@ -482,6 +485,13 @@ public List<PreConfiguredTokenFilter> getPreConfiguredTokenFilters() {
                 )
             )
         );
+        filters.add(
+            PreConfiguredTokenFilter.singleton(
+                "delimited_term_freq",
+                false,
+                input -> new DelimitedTermFrequencyTokenFilter(input, DelimitedTermFrequencyTokenFilterFactory.DEFAULT_DELIMITER)
+            )
+        );
         filters.add(PreConfiguredTokenFilter.singleton("dutch_stem", false, input -> new SnowballFilter(input, new DutchStemmer())));
         filters.add(PreConfiguredTokenFilter.singleton("edge_ngram", false, false, input -> new EdgeNGramTokenFilter(input, 1)));
         filters.add(PreConfiguredTokenFilter.openSearchVersion("edgeNGram", false, false, (reader, version) -> {
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactory.java
new file mode 100644
index 0000000000000..8929a7c54ef4c
--- /dev/null
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactory.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.analysis.common;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.miscellaneous.DelimitedTermFrequencyTokenFilter;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.env.Environment;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.analysis.AbstractTokenFilterFactory;
+
+public class DelimitedTermFrequencyTokenFilterFactory extends AbstractTokenFilterFactory {
+    public static final char DEFAULT_DELIMITER = '|';
+    private static final String DELIMITER = "delimiter";
+    private final char delimiter;
+
+    DelimitedTermFrequencyTokenFilterFactory(IndexSettings indexSettings, Environment environment, String name, Settings settings) {
+        super(indexSettings, name, settings);
+        delimiter = parseDelimiter(settings);
+    }
+
+    @Override
+    public TokenStream create(TokenStream tokenStream) {
+        return new DelimitedTermFrequencyTokenFilter(tokenStream, delimiter);
+    }
+
+    private static char parseDelimiter(Settings settings) {
+        String delimiter = settings.get(DELIMITER);
+        if (delimiter == null) {
+            return DEFAULT_DELIMITER;
+        } else if (delimiter.length() == 1) {
+            return delimiter.charAt(0);
+        }
+
+        throw new IllegalArgumentException(
+            "Setting [" + DELIMITER + "] must be a single, non-null character. [" + delimiter + "] was provided."
+        );
+    }
+}
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DutchStemTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DutchStemTokenFilterFactory.java
index 296740fb161ad..66e5cac331990 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DutchStemTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/DutchStemTokenFilterFactory.java
@@ -41,6 +41,7 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+
 import org.tartarus.snowball.ext.DutchStemmer;
 
 public class DutchStemTokenFilterFactory extends AbstractTokenFilterFactory {
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/EnglishPluralStemFilter.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/EnglishPluralStemFilter.java
new file mode 100644
index 0000000000000..c30318a31527b
--- /dev/null
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/EnglishPluralStemFilter.java
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.analysis.common;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.en.EnglishMinimalStemFilter;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.analysis.tokenattributes.KeywordAttribute;
+
+import java.io.IOException;
+
+public final class EnglishPluralStemFilter extends TokenFilter {
+    private final EnglishPluralStemmer stemmer = new EnglishPluralStemmer();
+    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+    private final KeywordAttribute keywordAttr = addAttribute(KeywordAttribute.class);
+
+    public EnglishPluralStemFilter(TokenStream input) {
+        super(input);
+    }
+
+    @Override
+    public boolean incrementToken() throws IOException {
+        if (input.incrementToken()) {
+            if (!keywordAttr.isKeyword()) {
+                final int newlen = stemmer.stem(termAtt.buffer(), termAtt.length());
+                termAtt.setLength(newlen);
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Plural stemmer for English based on the {@link EnglishMinimalStemFilter}
+     * <p>
+     * This stemmer removes plurals but beyond EnglishMinimalStemFilter adds
+     * four new suffix rules to remove dangling e characters:
+     * <ul>
+     * <li>xes - "boxes" becomes "box"</li>
+     * <li>sses - "dresses" becomes "dress"</li>
+     * <li>shes - "dishes" becomes "dish"</li>
+     * <li>tches - "watches" becomes "watch"</li>
+     * </ul>
+     * See https://github.com/elastic/elasticsearch/issues/42892
+     * <p>
+     * In addition the s stemmer logic is amended so that
+     * <ul>
+     * <li>ees-&gt;ee so that bees matches bee</li>
+     * <li>ies-&gt;y only on longer words to that ties matches tie</li>
+     * <li>oes-&gt;o rule so that tomatoes matches tomato but retains e for some words eg shoes to shoe</li>
+     * </ul>
+     */
+    public static class EnglishPluralStemmer {
+
+        // Words ending in oes that retain the e when stemmed
+        public static final char[][] oesExceptions = { "shoes".toCharArray(), "canoes".toCharArray(), "oboes".toCharArray() };
+        // Words ending in ches that retain the e when stemmed
+        public static final char[][] chesExceptions = {
+            "cliches".toCharArray(),
+            "avalanches".toCharArray(),
+            "mustaches".toCharArray(),
+            "moustaches".toCharArray(),
+            "quiches".toCharArray(),
+            "headaches".toCharArray(),
+            "heartaches".toCharArray(),
+            "porsches".toCharArray(),
+            "tranches".toCharArray(),
+            "caches".toCharArray() };
+
+        @SuppressWarnings("fallthrough")
+        public int stem(char s[], int len) {
+            if (len < 3 || s[len - 1] != 's') return len;
+
+            switch (s[len - 2]) {
+                case 'u':
+                case 's':
+                    return len;
+                case 'e':
+                    // Modified ies->y logic from original s-stemmer - only work on strings > 4
+                    // so spies -> spy still but pies->pie.
+                    // The original code also special-cased aies and eies for no good reason as far as I can tell.
+                    // ( no words of consequence - eg http://www.thefreedictionary.com/words-that-end-in-aies )
+                    if (len > 4 && s[len - 3] == 'i') {
+                        s[len - 3] = 'y';
+                        return len - 2;
+                    }
+
+                    // Suffix rules to remove any dangling "e"
+                    if (len > 3) {
+                        // xes (but >1 prefix so we can stem "boxes->box" but keep "axes->axe")
+                        if (len > 4 && s[len - 3] == 'x') {
+                            return len - 2;
+                        }
+                        // oes
+                        if (len > 3 && s[len - 3] == 'o') {
+                            if (isException(s, len, oesExceptions)) {
+                                // Only remove the S
+                                return len - 1;
+                            }
+                            // Remove the es
+                            return len - 2;
+                        }
+                        if (len > 4) {
+                            // shes/sses
+                            if (s[len - 4] == 's' && (s[len - 3] == 'h' || s[len - 3] == 's')) {
+                                return len - 2;
+                            }
+
+                            // ches
+                            if (len > 4) {
+                                if (s[len - 4] == 'c' && s[len - 3] == 'h') {
+                                    if (isException(s, len, chesExceptions)) {
+                                        // Only remove the S
+                                        return len - 1;
+                                    }
+                                    // Remove the es
+                                    return len - 2;
+
+                                }
+                            }
+                        }
+                    }
+
+                default:
+                    return len - 1;
+            }
+        }
+
+        private boolean isException(char[] s, int len, char[][] exceptionsList) {
+            for (char[] oesRule : exceptionsList) {
+                int rulePos = oesRule.length - 1;
+                int sPos = len - 1;
+                boolean matched = true;
+                while (rulePos >= 0 && sPos >= 0) {
+                    if (oesRule[rulePos] != s[sPos]) {
+                        matched = false;
+                        break;
+                    }
+                    rulePos--;
+                    sPos--;
+                }
+                if (matched) {
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+
+}
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FingerprintAnalyzerProvider.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FingerprintAnalyzerProvider.java
index f5c90dbd23b1e..ae315ff0a9cfe 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FingerprintAnalyzerProvider.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FingerprintAnalyzerProvider.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.CharArraySet;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.ParseField;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractIndexAnalyzerProvider;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FrenchStemTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FrenchStemTokenFilterFactory.java
index 15872d8b288c0..3aa546a79cde6 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FrenchStemTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/FrenchStemTokenFilterFactory.java
@@ -41,6 +41,7 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+
 import org.tartarus.snowball.ext.FrenchStemmer;
 
 public class FrenchStemTokenFilterFactory extends AbstractTokenFilterFactory {
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/HyphenationCompoundWordTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/HyphenationCompoundWordTokenFilterFactory.java
index 875c5261f8387..8d29a347caeb8 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/HyphenationCompoundWordTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/HyphenationCompoundWordTokenFilterFactory.java
@@ -32,18 +32,21 @@
 
 package org.opensearch.analysis.common;
 
+import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.compound.HyphenationCompoundWordTokenFilter;
 import org.apache.lucene.analysis.compound.hyphenation.HyphenationTree;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
-import org.xml.sax.InputSource;
+import org.opensearch.index.analysis.Analysis;
 
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 
+import org.xml.sax.InputSource;
+
 /**
  * Uses the {@link org.apache.lucene.analysis.compound.HyphenationCompoundWordTokenFilter} to decompound tokens based on hyphenation rules.
  *
@@ -61,13 +64,15 @@ public class HyphenationCompoundWordTokenFilterFactory extends AbstractCompoundW
             throw new IllegalArgumentException("hyphenation_patterns_path is a required setting.");
         }
 
-        Path hyphenationPatternsFile = env.configFile().resolve(hyphenationPatternsPath);
+        Path hyphenationPatternsFile = Analysis.resolveAnalyzerPath(env, hyphenationPatternsPath);
 
         try {
             InputStream in = Files.newInputStream(hyphenationPatternsFile);
             hyphenationTree = HyphenationCompoundWordTokenFilter.getHyphenationTree(new InputSource(in));
         } catch (Exception e) {
-            throw new IllegalArgumentException("Exception while reading hyphenation_patterns_path.", e);
+            LogManager.getLogger(HyphenationCompoundWordTokenFilterFactory.class)
+                .error("Exception while reading hyphenation_patterns_path ", e);
+            throw new IllegalArgumentException("Exception while reading hyphenation_patterns_path.");
         }
     }
 
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MappingCharFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MappingCharFilterFactory.java
index 7200b69135a30..d6d9f8975f2fc 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MappingCharFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MappingCharFilterFactory.java
@@ -39,6 +39,7 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractCharFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+import org.opensearch.index.analysis.MappingRule;
 import org.opensearch.index.analysis.NormalizingCharFilterFactory;
 
 import java.io.Reader;
@@ -53,13 +54,13 @@ public class MappingCharFilterFactory extends AbstractCharFilterFactory implemen
     MappingCharFilterFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) {
         super(indexSettings, name);
 
-        List<String> rules = Analysis.getWordList(env, settings, "mappings");
+        List<MappingRule<String, String>> rules = Analysis.parseWordList(env, settings, "mappings", this::parse);
         if (rules == null) {
             throw new IllegalArgumentException("mapping requires either `mappings` or `mappings_path` to be configured");
         }
 
         NormalizeCharMap.Builder normMapBuilder = new NormalizeCharMap.Builder();
-        parseRules(rules, normMapBuilder);
+        rules.forEach(rule -> normMapBuilder.add(rule.getLeft(), rule.getRight()));
         normMap = normMapBuilder.build();
     }
 
@@ -71,18 +72,13 @@ public Reader create(Reader tokenStream) {
     // source => target
     private static Pattern rulePattern = Pattern.compile("(.*)\\s*=>\\s*(.*)\\s*$");
 
-    /**
-     * parses a list of MappingCharFilter style rules into a normalize char map
-     */
-    private void parseRules(List<String> rules, NormalizeCharMap.Builder map) {
-        for (String rule : rules) {
-            Matcher m = rulePattern.matcher(rule);
-            if (!m.find()) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]");
-            String lhs = parseString(m.group(1).trim());
-            String rhs = parseString(m.group(2).trim());
-            if (lhs == null || rhs == null) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]. Illegal mapping.");
-            map.add(lhs, rhs);
-        }
+    private MappingRule<String, String> parse(String rule) {
+        Matcher m = rulePattern.matcher(rule);
+        if (!m.find()) throw new RuntimeException("Invalid mapping rule : [" + rule + "]");
+        String lhs = parseString(m.group(1).trim());
+        String rhs = parseString(m.group(2).trim());
+        if (lhs == null || rhs == null) throw new RuntimeException("Invalid mapping rule: [" + rule + "]. Illegal mapping.");
+        return new MappingRule<>(lhs, rhs);
     }
 
     char[] out = new char[256];
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MultiplexerTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MultiplexerTokenFilterFactory.java
index 27203efa6a230..fde47a53733e4 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MultiplexerTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/MultiplexerTokenFilterFactory.java
@@ -37,8 +37,8 @@
 import org.apache.lucene.analysis.miscellaneous.ConditionalTokenFilter;
 import org.apache.lucene.analysis.miscellaneous.RemoveDuplicatesTokenFilter;
 import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchSolrSynonymParser.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchSolrSynonymParser.java
index e50c37f03cd2e..e9d5d8cb25faf 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchSolrSynonymParser.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchSolrSynonymParser.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.analysis.common;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.synonym.SolrSynonymParser;
 import org.apache.lucene.util.CharsRef;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchWordnetSynonymParser.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchWordnetSynonymParser.java
index c7ae6c08411b9..9ecc38fde7e60 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchWordnetSynonymParser.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/OpenSearchWordnetSynonymParser.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.analysis.common;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.synonym.WordnetSynonymParser;
 import org.apache.lucene.util.CharsRef;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/PatternReplaceCharFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/PatternReplaceCharFilterFactory.java
index 3c6cdbf5c5a69..d6fca8ac67d55 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/PatternReplaceCharFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/PatternReplaceCharFilterFactory.java
@@ -32,9 +32,9 @@
 package org.opensearch.analysis.common;
 
 import org.apache.lucene.analysis.pattern.PatternReplaceCharFilter;
-import org.opensearch.common.Strings;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractCharFilterFactory;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SnowballTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SnowballTokenFilterFactory.java
index 591d1947c1eb8..759febb81728b 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SnowballTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SnowballTokenFilterFactory.java
@@ -33,8 +33,8 @@
 
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.snowball.SnowballFilter;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactory.java
index 89f0766542296..bdd6e01261443 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactory.java
@@ -40,24 +40,31 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+import org.opensearch.index.analysis.MappingRule;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 
 public class StemmerOverrideTokenFilterFactory extends AbstractTokenFilterFactory {
 
+    private static final String MAPPING_SEPARATOR = "=>";
     private final StemmerOverrideMap overrideMap;
 
     StemmerOverrideTokenFilterFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) throws IOException {
         super(indexSettings, name, settings);
 
-        List<String> rules = Analysis.getWordList(env, settings, "rules");
+        List<MappingRule<List<String>, String>> rules = Analysis.parseWordList(env, settings, "rules", this::parse);
         if (rules == null) {
             throw new IllegalArgumentException("stemmer override filter requires either `rules` or `rules_path` to be configured");
         }
 
         StemmerOverrideFilter.Builder builder = new StemmerOverrideFilter.Builder(false);
-        parseRules(rules, builder, "=>");
+        for (MappingRule<List<String>, String> rule : rules) {
+            for (String key : rule.getLeft()) {
+                builder.add(key, rule.getRight());
+            }
+        }
         overrideMap = builder.build();
 
     }
@@ -67,27 +74,26 @@ public TokenStream create(TokenStream tokenStream) {
         return new StemmerOverrideFilter(tokenStream, overrideMap);
     }
 
-    static void parseRules(List<String> rules, StemmerOverrideFilter.Builder builder, String mappingSep) {
-        for (String rule : rules) {
-            String[] sides = rule.split(mappingSep, -1);
-            if (sides.length != 2) {
-                throw new RuntimeException("Invalid Keyword override Rule:" + rule);
-            }
+    private MappingRule<List<String>, String> parse(String rule) {
+        String[] sides = rule.split(MAPPING_SEPARATOR, -1);
+        if (sides.length != 2) {
+            throw new RuntimeException("Invalid keyword override rule: " + rule);
+        }
 
-            String[] keys = sides[0].split(",", -1);
-            String override = sides[1].trim();
-            if (override.isEmpty() || override.indexOf(',') != -1) {
-                throw new RuntimeException("Invalid Keyword override Rule:" + rule);
-            }
+        String[] keys = sides[0].split(",", -1);
+        String override = sides[1].trim();
+        if (override.isEmpty() || override.indexOf(',') != -1) {
+            throw new RuntimeException("Invalid keyword override rule: " + rule);
+        }
 
-            for (String key : keys) {
-                String trimmedKey = key.trim();
-                if (trimmedKey.isEmpty()) {
-                    throw new RuntimeException("Invalid Keyword override Rule:" + rule);
-                }
-                builder.add(trimmedKey, override);
+        List<String> trimmedKeys = new ArrayList<>();
+        for (String key : keys) {
+            String trimmedKey = key.trim();
+            if (trimmedKey.isEmpty()) {
+                throw new RuntimeException("Invalid keyword override rule: " + rule);
             }
+            trimmedKeys.add(trimmedKey);
         }
+        return new MappingRule<>(trimmedKeys, override);
     }
-
 }
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerTokenFilterFactory.java
index 5d96f01265cf6..5506626e40da0 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/StemmerTokenFilterFactory.java
@@ -67,11 +67,14 @@
 import org.apache.lucene.analysis.ru.RussianLightStemFilter;
 import org.apache.lucene.analysis.snowball.SnowballFilter;
 import org.apache.lucene.analysis.sv.SwedishLightStemFilter;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
+
+import java.io.IOException;
+
 import org.tartarus.snowball.ext.ArmenianStemmer;
 import org.tartarus.snowball.ext.BasqueStemmer;
 import org.tartarus.snowball.ext.CatalanStemmer;
@@ -97,8 +100,6 @@
 import org.tartarus.snowball.ext.SwedishStemmer;
 import org.tartarus.snowball.ext.TurkishStemmer;
 
-import java.io.IOException;
-
 public class StemmerTokenFilterFactory extends AbstractTokenFilterFactory {
 
     private static final TokenStream EMPTY_TOKEN_STREAM = new EmptyTokenStream();
@@ -154,6 +155,8 @@ public TokenStream create(TokenStream tokenStream) {
                 return new SnowballFilter(tokenStream, new EnglishStemmer());
             } else if ("minimal_english".equalsIgnoreCase(language) || "minimalEnglish".equalsIgnoreCase(language)) {
                 return new EnglishMinimalStemFilter(tokenStream);
+            } else if ("plural_english".equalsIgnoreCase(language) || "pluralEnglish".equalsIgnoreCase(language)) {
+                return new EnglishPluralStemFilter(tokenStream);
             } else if ("possessive_english".equalsIgnoreCase(language) || "possessiveEnglish".equalsIgnoreCase(language)) {
                 return new EnglishPossessiveFilter(tokenStream);
 
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SynonymTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SynonymTokenFilterFactory.java
index dc6b5b2dd8b7b..01a65e87d7466 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SynonymTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/SynonymTokenFilterFactory.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.analysis.common;
 
+import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.synonym.SynonymFilter;
@@ -155,14 +156,15 @@ SynonymMap buildSynonyms(Analyzer analyzer, Reader rules) {
             }
             return parser.build();
         } catch (Exception e) {
-            throw new IllegalArgumentException("failed to build synonyms", e);
+            LogManager.getLogger(SynonymTokenFilterFactory.class).error("Failed to build synonyms: ", e);
+            throw new IllegalArgumentException("Failed to build synonyms");
         }
     }
 
     Reader getRulesFromSettings(Environment env) {
         Reader rulesReader;
         if (settings.getAsList("synonyms", null) != null) {
-            List<String> rulesList = Analysis.getWordList(env, settings, "synonyms");
+            List<String> rulesList = Analysis.parseWordList(env, settings, "synonyms", s -> s);
             StringBuilder sb = new StringBuilder();
             for (String line : rulesList) {
                 sb.append(line).append(System.lineSeparator());
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/UAX29URLEmailTokenizerFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/UAX29URLEmailTokenizerFactory.java
index 8d6e0ec0815b4..8d9eb4902daae 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/UAX29URLEmailTokenizerFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/UAX29URLEmailTokenizerFactory.java
@@ -33,8 +33,8 @@
 package org.opensearch.analysis.common;
 
 import org.apache.lucene.analysis.Tokenizer;
-import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.analysis.email.UAX29URLEmailTokenizer;
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactory.java
index 31d52d030cb71..15f4cf8cba0e0 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactory.java
@@ -41,11 +41,13 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+import org.opensearch.index.analysis.MappingRule;
 import org.opensearch.index.analysis.TokenFilterFactory;
 
 import java.util.List;
 import java.util.Set;
 
+import static org.opensearch.analysis.common.WordDelimiterTokenFilterFactory.parseTypes;
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.CATENATE_ALL;
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.CATENATE_NUMBERS;
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.CATENATE_WORDS;
@@ -56,7 +58,6 @@
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.SPLIT_ON_CASE_CHANGE;
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.SPLIT_ON_NUMERICS;
 import static org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter.STEM_ENGLISH_POSSESSIVE;
-import static org.opensearch.analysis.common.WordDelimiterTokenFilterFactory.parseTypes;
 
 public class WordDelimiterGraphTokenFilterFactory extends AbstractTokenFilterFactory {
     private final byte[] charTypeTable;
@@ -73,7 +74,12 @@ public WordDelimiterGraphTokenFilterFactory(IndexSettings indexSettings, Environ
         // . => DIGIT
         // \u002C => DIGIT
         // \u200D => ALPHANUM
-        List<String> charTypeTableValues = Analysis.getWordList(env, settings, "type_table");
+        List<MappingRule<Character, Byte>> charTypeTableValues = Analysis.parseWordList(
+            env,
+            settings,
+            "type_table",
+            WordDelimiterTokenFilterFactory::parse
+        );
         if (charTypeTableValues == null) {
             this.charTypeTable = WordDelimiterIterator.DEFAULT_WORD_DELIM_TABLE;
         } else {
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterTokenFilterFactory.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterTokenFilterFactory.java
index d40acfa05dd21..96e50206fb53d 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterTokenFilterFactory.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/WordDelimiterTokenFilterFactory.java
@@ -41,6 +41,7 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AbstractTokenFilterFactory;
 import org.opensearch.index.analysis.Analysis;
+import org.opensearch.index.analysis.MappingRule;
 import org.opensearch.index.analysis.TokenFilterFactory;
 
 import java.util.Collection;
@@ -76,7 +77,12 @@ public WordDelimiterTokenFilterFactory(IndexSettings indexSettings, Environment
         // . => DIGIT
         // \u002C => DIGIT
         // \u200D => ALPHANUM
-        List<String> charTypeTableValues = Analysis.getWordList(env, settings, "type_table");
+        List<MappingRule<Character, Byte>> charTypeTableValues = Analysis.parseWordList(
+            env,
+            settings,
+            "type_table",
+            WordDelimiterTokenFilterFactory::parse
+        );
         if (charTypeTableValues == null) {
             this.charTypeTable = WordDelimiterIterator.DEFAULT_WORD_DELIM_TABLE;
         } else {
@@ -127,19 +133,23 @@ public int getFlag(int flag, Settings settings, String key, boolean defaultValue
     // source => type
     private static Pattern typePattern = Pattern.compile("(.*)\\s*=>\\s*(.*)\\s*$");
 
+    static MappingRule<Character, Byte> parse(String rule) {
+        Matcher m = typePattern.matcher(rule);
+        if (!m.find()) throw new RuntimeException("Invalid mapping rule: [" + rule + "]");
+        String lhs = parseString(m.group(1).trim());
+        Byte rhs = parseType(m.group(2).trim());
+        if (lhs.length() != 1) throw new RuntimeException("Invalid mapping rule: [" + rule + "]. Only a single character is allowed.");
+        if (rhs == null) throw new RuntimeException("Invalid mapping rule: [" + rule + "]. Illegal type.");
+        return new MappingRule<>(lhs.charAt(0), rhs);
+    }
+
     /**
      * parses a list of MappingCharFilter style rules into a custom byte[] type table
      */
-    static byte[] parseTypes(Collection<String> rules) {
+    static byte[] parseTypes(Collection<MappingRule<Character, Byte>> rules) {
         SortedMap<Character, Byte> typeMap = new TreeMap<>();
-        for (String rule : rules) {
-            Matcher m = typePattern.matcher(rule);
-            if (!m.find()) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]");
-            String lhs = parseString(m.group(1).trim());
-            Byte rhs = parseType(m.group(2).trim());
-            if (lhs.length() != 1) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]. Only a single character is allowed.");
-            if (rhs == null) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]. Illegal type.");
-            typeMap.put(lhs.charAt(0), rhs);
+        for (MappingRule<Character, Byte> rule : rules) {
+            typeMap.put(rule.getLeft(), rule.getRight());
         }
 
         // ensure the table is always at least as big as DEFAULT_WORD_DELIM_TABLE for performance
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/BaseWordDelimiterTokenFilterFactoryTestCase.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/BaseWordDelimiterTokenFilterFactoryTestCase.java
index 9d54776755766..d28155272a9db 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/BaseWordDelimiterTokenFilterFactoryTestCase.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/BaseWordDelimiterTokenFilterFactoryTestCase.java
@@ -195,4 +195,24 @@ public void testStemEnglishPossessive() throws IOException {
         tokenizer.setReader(new StringReader(source));
         assertTokenStreamContents(tokenFilter.create(tokenizer), expected);
     }
+
+    private void createTokenFilterFactoryWithTypeTable(String[] rules) throws IOException {
+        OpenSearchTestCase.TestAnalysis analysis = AnalysisTestsHelper.createTestAnalysisFromSettings(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put("index.analysis.filter.my_word_delimiter.type", type)
+                .putList("index.analysis.filter.my_word_delimiter.type_table", rules)
+                .put("index.analysis.filter.my_word_delimiter.catenate_words", "true")
+                .put("index.analysis.filter.my_word_delimiter.generate_word_parts", "true")
+                .build(),
+            new CommonAnalysisPlugin()
+        );
+        analysis.tokenFilter.get("my_word_delimiter");
+    }
+
+    public void testTypeTableParsingError() {
+        String[] rules = { "# This is a comment", "# => ALPHANUM", "$ => DIGIT", "\\u200D => ALPHANUM", "abc => ALPHA" };
+        RuntimeException ex = expectThrows(RuntimeException.class, () -> createTokenFilterFactoryWithTypeTable(rules));
+        assertEquals("Line [5]: Invalid mapping rule: [abc => ALPHA]. Only a single character is allowed.", ex.getMessage());
+    }
 }
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CharGroupTokenizerFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CharGroupTokenizerFactoryTests.java
index 54ab1bc154641..459f463c3ee28 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CharGroupTokenizerFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CharGroupTokenizerFactoryTests.java
@@ -33,13 +33,14 @@
 package org.opensearch.analysis.common;
 
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.util.CharTokenizer;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.io.IOException;
 import java.io.Reader;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CommonAnalysisFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CommonAnalysisFactoryTests.java
index 4cf0d1de28717..e0e99cdc31672 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CommonAnalysisFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CommonAnalysisFactoryTests.java
@@ -145,6 +145,7 @@ protected Map<String, Class<?>> getTokenFilters() {
         filters.put("cjkwidth", CJKWidthFilterFactory.class);
         filters.put("cjkbigram", CJKBigramFilterFactory.class);
         filters.put("delimitedpayload", DelimitedPayloadTokenFilterFactory.class);
+        filters.put("delimitedtermfrequency", DelimitedTermFrequencyTokenFilterFactory.class);
         filters.put("keepword", KeepWordFilterFactory.class);
         filters.put("type", KeepTypesFilterFactory.class);
         filters.put("classic", ClassicFilterFactory.class);
@@ -202,6 +203,7 @@ protected Map<String, Class<?>> getPreConfiguredTokenFilters() {
         filters.put("decimal_digit", null);
         filters.put("delimited_payload_filter", org.apache.lucene.analysis.payloads.DelimitedPayloadTokenFilterFactory.class);
         filters.put("delimited_payload", org.apache.lucene.analysis.payloads.DelimitedPayloadTokenFilterFactory.class);
+        filters.put("delimited_term_freq", org.apache.lucene.analysis.miscellaneous.DelimitedTermFrequencyTokenFilterFactory.class);
         filters.put("dutch_stem", SnowballPorterFilterFactory.class);
         filters.put("edge_ngram", null);
         filters.put("edgeNGram", null);
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CompoundAnalysisTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CompoundAnalysisTests.java
index e5ce7c818f72b..1955b7eaa0e45 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CompoundAnalysisTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/CompoundAnalysisTests.java
@@ -47,8 +47,8 @@
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.indices.analysis.AnalysisModule.AnalysisProvider;
 import org.opensearch.plugins.AnalysisPlugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.MatcherAssert;
 
 import java.io.IOException;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ConcatenateGraphTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ConcatenateGraphTokenFilterFactoryTests.java
index 509010e209088..a1cbfd527b21e 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ConcatenateGraphTokenFilterFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ConcatenateGraphTokenFilterFactoryTests.java
@@ -8,12 +8,12 @@
 
 package org.opensearch.analysis.common;
 
-import org.apache.lucene.tests.analysis.CannedTokenStream;
-import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.miscellaneous.ConcatenateGraphFilter;
+import org.apache.lucene.tests.analysis.CannedTokenStream;
+import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.util.automaton.TooComplexToDeterminizeException;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.cluster.metadata.IndexMetadata;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactoryTests.java
new file mode 100644
index 0000000000000..bb8698e535a62
--- /dev/null
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DelimitedTermFrequencyTokenFilterFactoryTests.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.analysis.common;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.WhitespaceTokenizer;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.analysis.tokenattributes.TermFrequencyAttribute;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.env.Environment;
+import org.opensearch.index.analysis.AnalysisTestsHelper;
+import org.opensearch.index.analysis.TokenFilterFactory;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
+
+import java.io.StringReader;
+
+public class DelimitedTermFrequencyTokenFilterFactoryTests extends OpenSearchTokenStreamTestCase {
+
+    public void testDefault() throws Exception {
+        OpenSearchTestCase.TestAnalysis analysis = AnalysisTestsHelper.createTestAnalysisFromSettings(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put("index.analysis.filter.my_delimited_term_freq.type", "delimited_term_freq")
+                .build(),
+            new CommonAnalysisPlugin()
+        );
+        doTest(analysis, "cat|4 dog|5");
+    }
+
+    public void testDelimiter() throws Exception {
+        OpenSearchTestCase.TestAnalysis analysis = AnalysisTestsHelper.createTestAnalysisFromSettings(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put("index.analysis.filter.my_delimited_term_freq.type", "delimited_term_freq")
+                .put("index.analysis.filter.my_delimited_term_freq.delimiter", ":")
+                .build(),
+            new CommonAnalysisPlugin()
+        );
+        doTest(analysis, "cat:4 dog:5");
+    }
+
+    public void testDelimiterLongerThanOneCharThrows() {
+        IllegalArgumentException ex = expectThrows(
+            IllegalArgumentException.class,
+            () -> AnalysisTestsHelper.createTestAnalysisFromSettings(
+                Settings.builder()
+                    .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                    .put("index.analysis.filter.my_delimited_term_freq.type", "delimited_term_freq")
+                    .put("index.analysis.filter.my_delimited_term_freq.delimiter", "^^")
+                    .build(),
+                new CommonAnalysisPlugin()
+            )
+        );
+
+        assertEquals("Setting [delimiter] must be a single, non-null character. [^^] was provided.", ex.getMessage());
+    }
+
+    private void doTest(OpenSearchTestCase.TestAnalysis analysis, String source) throws Exception {
+        TokenFilterFactory tokenFilter = analysis.tokenFilter.get("my_delimited_term_freq");
+        Tokenizer tokenizer = new WhitespaceTokenizer();
+        tokenizer.setReader(new StringReader(source));
+
+        TokenStream stream = tokenFilter.create(tokenizer);
+
+        CharTermAttribute termAtt = stream.getAttribute(CharTermAttribute.class);
+        TermFrequencyAttribute tfAtt = stream.getAttribute(TermFrequencyAttribute.class);
+        stream.reset();
+        assertTermEquals("cat", stream, termAtt, tfAtt, 4);
+        assertTermEquals("dog", stream, termAtt, tfAtt, 5);
+        assertFalse(stream.incrementToken());
+        stream.end();
+        stream.close();
+    }
+
+    void assertTermEquals(String expected, TokenStream stream, CharTermAttribute termAtt, TermFrequencyAttribute tfAtt, int expectedTf)
+        throws Exception {
+        assertTrue(stream.incrementToken());
+        assertEquals(expected, termAtt.toString());
+        assertEquals(expectedTf, tfAtt.getTermFrequency());
+    }
+}
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DisableGraphQueryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DisableGraphQueryTests.java
index 35915af8f263d..0d1448c9b276f 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DisableGraphQueryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/DisableGraphQueryTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.analysis.common;
 
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.MultiPhraseQuery;
+import org.apache.lucene.search.PhraseQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
-import org.apache.lucene.search.BooleanQuery;
-import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.search.PhraseQuery;
-import org.apache.lucene.search.MultiPhraseQuery;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.query.MatchPhraseQueryBuilder;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/EdgeNGramTokenizerTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/EdgeNGramTokenizerTests.java
index 07ac0d69428af..a8aafc402baed 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/EdgeNGramTokenizerTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/EdgeNGramTokenizerTests.java
@@ -37,15 +37,15 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/FlattenGraphTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/FlattenGraphTokenFilterFactoryTests.java
index 7d9555923e4ef..5e8365409a725 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/FlattenGraphTokenFilterFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/FlattenGraphTokenFilterFactoryTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.analysis.common;
 
+import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.tests.analysis.CannedTokenStream;
 import org.apache.lucene.tests.analysis.Token;
-import org.apache.lucene.analysis.TokenStream;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.io.IOException;
 
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/HighlighterWithAnalyzersTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/HighlighterWithAnalyzersTests.java
index 57c959a4f0b65..0ffb7f2114f28 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/HighlighterWithAnalyzersTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/HighlighterWithAnalyzersTests.java
@@ -32,16 +32,19 @@
 
 package org.opensearch.analysis.common;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.Operator;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -50,19 +53,40 @@
 import static org.opensearch.client.Requests.searchRequest;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.boolQuery;
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.matchPhrasePrefixQuery;
 import static org.opensearch.index.query.QueryBuilders.matchPhraseQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.highlight;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHighlight;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.startsWith;
 
-public class HighlighterWithAnalyzersTests extends OpenSearchIntegTestCase {
+public class HighlighterWithAnalyzersTests extends ParameterizedOpenSearchIntegTestCase {
+
+    public HighlighterWithAnalyzersTests(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(CommonAnalysisPlugin.class);
@@ -270,9 +294,13 @@ public void testPhrasePrefix() throws IOException {
         refresh();
         logger.info("--> highlighting and searching on field0");
 
-        SearchSourceBuilder source = searchSource().query(matchPhrasePrefixQuery("field0", "bro"))
-            .highlighter(highlight().field("field0").order("score").preTags("<x>").postTags("</x>"));
+        SearchSourceBuilder source = searchSource().query(matchAllQuery());
         SearchResponse searchResponse = client().search(searchRequest("first_test_index").source(source)).actionGet();
+        assertHitCount(searchResponse, 2);
+
+        source = searchSource().query(matchPhrasePrefixQuery("field0", "bro"))
+            .highlighter(highlight().field("field0").order("score").preTags("<x>").postTags("</x>"));
+        searchResponse = client().search(searchRequest("first_test_index").source(source)).actionGet();
 
         assertHighlight(searchResponse, 0, "field0", 0, 1, equalTo("The quick <x>brown</x> fox jumps over the lazy dog"));
 
@@ -415,6 +443,7 @@ public void testPhrasePrefix() throws IOException {
     public static XContentBuilder type1TermVectorMapping() throws IOException {
         return XContentFactory.jsonBuilder()
             .startObject()
+            .startObject("_doc")
             .startObject("properties")
             .startObject("field1")
             .field("type", "text")
@@ -425,6 +454,7 @@ public static XContentBuilder type1TermVectorMapping() throws IOException {
             .field("term_vector", "with_positions_offsets")
             .endObject()
             .endObject()
+            .endObject()
             .endObject();
     }
 }
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MappingCharFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MappingCharFilterFactoryTests.java
new file mode 100644
index 0000000000000..2ef9f4e91655f
--- /dev/null
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MappingCharFilterFactoryTests.java
@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.analysis.common;
+
+import org.apache.lucene.analysis.CharFilter;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.env.Environment;
+import org.opensearch.index.analysis.AnalysisTestsHelper;
+import org.opensearch.index.analysis.CharFilterFactory;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.Arrays;
+
+public class MappingCharFilterFactoryTests extends OpenSearchTestCase {
+    public static CharFilterFactory create(String... rules) throws IOException {
+        OpenSearchTestCase.TestAnalysis analysis = AnalysisTestsHelper.createTestAnalysisFromSettings(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put("index.analysis.analyzer.my_analyzer.tokenizer", "standard")
+                .put("index.analysis.analyzer.my_analyzer.char_filter", "my_mappings_char_filter")
+                .put("index.analysis.char_filter.my_mappings_char_filter.type", "mapping")
+                .putList("index.analysis.char_filter.my_mappings_char_filter.mappings", rules)
+                .build(),
+            new CommonAnalysisPlugin()
+        );
+
+        return analysis.charFilter.get("my_mappings_char_filter");
+    }
+
+    public void testRulesOk() throws IOException {
+        MappingCharFilterFactory mappingCharFilterFactory = (MappingCharFilterFactory) create(
+            "# This is a comment",
+            "# => _hashtag_",
+            ":) => _happy_",
+            ":( => _sad_"
+        );
+        CharFilter inputReader = (CharFilter) mappingCharFilterFactory.create(new StringReader("I'm so :), I'm so :( #confused"));
+        char[] tempBuff = new char[14];
+        StringBuilder output = new StringBuilder();
+        while (true) {
+            int length = inputReader.read(tempBuff);
+            if (length == -1) break;
+            output.append(tempBuff, 0, length);
+        }
+        assertEquals("I'm so _happy_, I'm so _sad_ _hashtag_confused", output.toString());
+    }
+
+    public void testRuleError() {
+        for (String rule : Arrays.asList(
+            "",        // empty
+            "a",       // no arrow
+            "a:>b"     // invalid delimiter
+        )) {
+            RuntimeException ex = expectThrows(RuntimeException.class, () -> create(rule));
+            assertEquals("Line [1]: Invalid mapping rule : [" + rule + "]", ex.getMessage());
+        }
+    }
+
+    public void testRulePartError() {
+        RuntimeException ex = expectThrows(
+            RuntimeException.class,
+            () -> create("# This is a comment", "# => _hashtag_", ":) => _happy_", "a:b")
+        );
+        assertEquals("Line [4]: Invalid mapping rule : [a:b]", ex.getMessage());
+    }
+}
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MultiplexerTokenFilterTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MultiplexerTokenFilterTests.java
index 167f61464da1b..1d3858f581c3a 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MultiplexerTokenFilterTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/MultiplexerTokenFilterTests.java
@@ -41,8 +41,8 @@
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/NGramTokenizerFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/NGramTokenizerFactoryTests.java
index 49ccc742a355c..21b65059cf688 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/NGramTokenizerFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/NGramTokenizerFactoryTests.java
@@ -32,27 +32,27 @@
 
 package org.opensearch.analysis.common;
 
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ngram.EdgeNGramTokenFilter;
 import org.apache.lucene.analysis.reverse.ReverseStringFilter;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
 import java.io.StringReader;
 import java.util.Arrays;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.scaledRandomIntBetween;
 import static org.hamcrest.Matchers.instanceOf;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.scaledRandomIntBetween;
 
 public class NGramTokenizerFactoryTests extends OpenSearchTokenStreamTestCase {
     public void testParseTokenChars() {
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PathHierarchyTokenizerFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PathHierarchyTokenizerFactoryTests.java
index 73c104a5b7200..1fe7c582449ec 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PathHierarchyTokenizerFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PathHierarchyTokenizerFactoryTests.java
@@ -36,9 +36,9 @@
 
 import org.apache.lucene.analysis.Tokenizer;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.io.IOException;
 import java.io.StringReader;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PatternCaptureTokenFilterTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PatternCaptureTokenFilterTests.java
index 5cd18a5b01f18..4d882354b1709 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PatternCaptureTokenFilterTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PatternCaptureTokenFilterTests.java
@@ -39,8 +39,8 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import static org.opensearch.test.OpenSearchTestCase.createTestAnalysis;
 import static org.hamcrest.Matchers.containsString;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PredicateTokenScriptFilterTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PredicateTokenScriptFilterTests.java
index c16f4f37846ec..2856eef885385 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PredicateTokenScriptFilterTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/PredicateTokenScriptFilterTests.java
@@ -44,8 +44,8 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.ScriptService;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ScriptedConditionTokenFilterTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ScriptedConditionTokenFilterTests.java
index 9212fcad2850d..202ce7233d3e8 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ScriptedConditionTokenFilterTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/ScriptedConditionTokenFilterTests.java
@@ -44,8 +44,8 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.ScriptService;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import java.util.Collections;
 
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactoryTests.java
index 96e05efa97768..9e3345aa30dca 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerOverrideTokenFilterFactoryTests.java
@@ -46,7 +46,6 @@
 import java.io.IOException;
 import java.io.StringReader;
 import java.util.Arrays;
-import java.util.Locale;
 
 public class StemmerOverrideTokenFilterFactoryTests extends OpenSearchTokenStreamTestCase {
     @Rule
@@ -76,11 +75,8 @@ public void testRuleError() {
             "=>a",     // no keys
             "a,=>b"    // empty key
         )) {
-            expectThrows(
-                RuntimeException.class,
-                String.format(Locale.ROOT, "Should fail for invalid rule: '%s'", rule),
-                () -> create(rule)
-            );
+            RuntimeException ex = expectThrows(RuntimeException.class, () -> create(rule));
+            assertEquals("Line [1]: Invalid keyword override rule: " + rule, ex.getMessage());
         }
     }
 
@@ -90,4 +86,9 @@ public void testRulesOk() throws IOException {
         tokenizer.setReader(new StringReader("a b c"));
         assertTokenStreamContents(tokenFilterFactory.create(tokenizer), new String[] { "1", "2", "2" });
     }
+
+    public void testRulePartError() {
+        RuntimeException ex = expectThrows(RuntimeException.class, () -> create("a => 1", "b,c => 2", "# This is a comment", "=>a=>b"));
+        assertEquals("Line [4]: Invalid keyword override rule: =>a=>b", ex.getMessage());
+    }
 }
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerTokenFilterFactoryTests.java
index fca64f4915cbf..45147ff813797 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerTokenFilterFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/StemmerTokenFilterFactoryTests.java
@@ -50,9 +50,9 @@
 import java.io.IOException;
 import java.io.StringReader;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.scaledRandomIntBetween;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.hamcrest.Matchers.instanceOf;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.scaledRandomIntBetween;
 
 public class StemmerTokenFilterFactoryTests extends OpenSearchTokenStreamTestCase {
 
@@ -111,6 +111,83 @@ public void testPorter2FilterFactory() throws IOException {
         }
     }
 
+    public void testEnglishPluralFilter() throws IOException {
+        int iters = scaledRandomIntBetween(20, 100);
+        for (int i = 0; i < iters; i++) {
+
+            Version v = VersionUtils.randomVersion(random());
+            Settings settings = Settings.builder()
+                .put("index.analysis.filter.my_plurals.type", "stemmer")
+                .put("index.analysis.filter.my_plurals.language", "plural_english")
+                .put("index.analysis.analyzer.my_plurals.tokenizer", "whitespace")
+                .put("index.analysis.analyzer.my_plurals.filter", "my_plurals")
+                .put(SETTING_VERSION_CREATED, v)
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .build();
+
+            OpenSearchTestCase.TestAnalysis analysis = AnalysisTestsHelper.createTestAnalysisFromSettings(settings, PLUGIN);
+            TokenFilterFactory tokenFilter = analysis.tokenFilter.get("my_plurals");
+            assertThat(tokenFilter, instanceOf(StemmerTokenFilterFactory.class));
+            Tokenizer tokenizer = new WhitespaceTokenizer();
+            tokenizer.setReader(new StringReader("dresses"));
+            TokenStream create = tokenFilter.create(tokenizer);
+            IndexAnalyzers indexAnalyzers = analysis.indexAnalyzers;
+            NamedAnalyzer analyzer = indexAnalyzers.get("my_plurals");
+            assertThat(create, instanceOf(EnglishPluralStemFilter.class));
+
+            // Check old EnglishMinimalStemmer ("S" stemmer) logic
+            assertAnalyzesTo(analyzer, "phones", new String[] { "phone" });
+            assertAnalyzesTo(analyzer, "horses", new String[] { "horse" });
+            assertAnalyzesTo(analyzer, "cameras", new String[] { "camera" });
+
+            // The orginal s stemmer gives up on stemming oes words because English has no fixed rule for the stem
+            // (see https://howtospell.co.uk/making-O-words-plural )
+            // This stemmer removes the es but retains e for a small number of exceptions
+            assertAnalyzesTo(analyzer, "mosquitoes", new String[] { "mosquito" });
+            assertAnalyzesTo(analyzer, "heroes", new String[] { "hero" });
+            // oes exceptions that retain the e.
+            assertAnalyzesTo(analyzer, "shoes", new String[] { "shoe" });
+            assertAnalyzesTo(analyzer, "horseshoes", new String[] { "horseshoe" });
+            assertAnalyzesTo(analyzer, "canoes", new String[] { "canoe" });
+            assertAnalyzesTo(analyzer, "oboes", new String[] { "oboe" });
+
+            // Check improved EnglishPluralStemFilter logic
+            // sses
+            assertAnalyzesTo(analyzer, "dresses", new String[] { "dress" });
+            assertAnalyzesTo(analyzer, "possess", new String[] { "possess" });
+            assertAnalyzesTo(analyzer, "possesses", new String[] { "possess" });
+            // xes
+            assertAnalyzesTo(analyzer, "boxes", new String[] { "box" });
+            assertAnalyzesTo(analyzer, "axes", new String[] { "axe" });
+            // shes
+            assertAnalyzesTo(analyzer, "dishes", new String[] { "dish" });
+            assertAnalyzesTo(analyzer, "washes", new String[] { "wash" });
+            // ees
+            assertAnalyzesTo(analyzer, "employees", new String[] { "employee" });
+            assertAnalyzesTo(analyzer, "bees", new String[] { "bee" });
+            // tch
+            assertAnalyzesTo(analyzer, "watches", new String[] { "watch" });
+            assertAnalyzesTo(analyzer, "itches", new String[] { "itch" });
+            // ies->y but only for length >4
+            assertAnalyzesTo(analyzer, "spies", new String[] { "spy" });
+            assertAnalyzesTo(analyzer, "ties", new String[] { "tie" });
+            assertAnalyzesTo(analyzer, "lies", new String[] { "lie" });
+            assertAnalyzesTo(analyzer, "pies", new String[] { "pie" });
+            assertAnalyzesTo(analyzer, "dies", new String[] { "die" });
+
+            assertAnalyzesTo(analyzer, "lunches", new String[] { "lunch" });
+            assertAnalyzesTo(analyzer, "avalanches", new String[] { "avalanche" });
+            assertAnalyzesTo(analyzer, "headaches", new String[] { "headache" });
+            assertAnalyzesTo(analyzer, "caches", new String[] { "cache" });
+            assertAnalyzesTo(analyzer, "beaches", new String[] { "beach" });
+            assertAnalyzesTo(analyzer, "britches", new String[] { "britch" });
+            assertAnalyzesTo(analyzer, "cockroaches", new String[] { "cockroach" });
+            assertAnalyzesTo(analyzer, "cliches", new String[] { "cliche" });
+            assertAnalyzesTo(analyzer, "quiches", new String[] { "quiche" });
+
+        }
+    }
+
     public void testMultipleLanguagesThrowsException() throws IOException {
         Version v = VersionUtils.randomVersion(random());
         Settings settings = Settings.builder()
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/SynonymsAnalysisTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/SynonymsAnalysisTests.java
index 8094e24b9adc8..d6285c64b09f5 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/SynonymsAnalysisTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/SynonymsAnalysisTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.analysis.common;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.tests.analysis.BaseTokenStreamTestCase;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -47,8 +47,8 @@
 import org.opensearch.index.analysis.PreConfiguredTokenFilter;
 import org.opensearch.index.analysis.TokenFilterFactory;
 import org.opensearch.index.analysis.TokenizerFactory;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.hamcrest.MatcherAssert;
 
@@ -117,7 +117,7 @@ public void testSynonymWordDeleteByAnalyzer() throws IOException {
             fail("fail! due to synonym word deleted by analyzer");
         } catch (Exception e) {
             assertThat(e, instanceOf(IllegalArgumentException.class));
-            assertThat(e.getMessage(), startsWith("failed to build synonyms"));
+            assertThat(e.getMessage(), startsWith("Failed to build synonyms"));
         }
     }
 
@@ -138,7 +138,7 @@ public void testExpandSynonymWordDeleteByAnalyzer() throws IOException {
             fail("fail! due to synonym word deleted by analyzer");
         } catch (Exception e) {
             assertThat(e, instanceOf(IllegalArgumentException.class));
-            assertThat(e.getMessage(), startsWith("failed to build synonyms"));
+            assertThat(e.getMessage(), startsWith("Failed to build synonyms"));
         }
     }
 
@@ -244,10 +244,9 @@ public void testShingleFilters() {
             .build();
         IndexSettings idxSettings = IndexSettingsModule.newIndexSettings("index", settings);
 
-        expectThrows(
-            IllegalArgumentException.class,
-            () -> { indexAnalyzers = createTestAnalysis(idxSettings, settings, new CommonAnalysisPlugin()).indexAnalyzers; }
-        );
+        expectThrows(IllegalArgumentException.class, () -> {
+            indexAnalyzers = createTestAnalysis(idxSettings, settings, new CommonAnalysisPlugin()).indexAnalyzers;
+        });
 
     }
 
@@ -308,7 +307,9 @@ public void testPreconfiguredTokenFilters() throws IOException {
                 IllegalArgumentException e = expectThrows(
                     IllegalArgumentException.class,
                     "Expected exception for factory " + tf.getName(),
-                    () -> { tf.get(idxSettings, null, tf.getName(), settings).getSynonymFilter(); }
+                    () -> {
+                        tf.get(idxSettings, null, tf.getName(), settings).getSynonymFilter();
+                    }
                 );
                 assertEquals(tf.getName(), "Token filter [" + tf.getName() + "] cannot be used to parse synonyms", e.getMessage());
             } else {
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/UniqueTokenFilterTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/UniqueTokenFilterTests.java
index a321fd4a5879c..ba8de4db07396 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/UniqueTokenFilterTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/UniqueTokenFilterTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.analysis.common;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WhitespaceTokenizerFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WhitespaceTokenizerFactoryTests.java
index c0034c0e8ef20..0d4db04141e45 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WhitespaceTokenizerFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WhitespaceTokenizerFactoryTests.java
@@ -38,10 +38,10 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.io.Reader;
diff --git a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactoryTests.java b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactoryTests.java
index 6129971a69e18..784b92e4a9324 100644
--- a/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactoryTests.java
+++ b/modules/analysis-common/src/test/java/org/opensearch/analysis/common/WordDelimiterGraphTokenFilterFactoryTests.java
@@ -45,8 +45,8 @@
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.analysis.TokenFilterFactory;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/cjk_analysis.json b/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/cjk_analysis.json
index 89a1281473cd7..c69b889c914a4 100644
--- a/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/cjk_analysis.json
+++ b/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/cjk_analysis.json
@@ -34,4 +34,4 @@
          }
       }
    }
-}
\ No newline at end of file
+}
diff --git a/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/pattern_capture.json b/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/pattern_capture.json
index d82fb987e6ed2..5057a1e6d7f9e 100644
--- a/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/pattern_capture.json
+++ b/modules/analysis-common/src/test/resources/org/opensearch/analysis/common/pattern_capture.json
@@ -43,4 +43,4 @@
          }
       }
    }
-}
\ No newline at end of file
+}
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/10_basic.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/10_basic.yml
index ca6cd2e953be4..c42438797496c 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/10_basic.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/10_basic.yml
@@ -5,10 +5,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: analysis-common } }
+    - contains:  { nodes.$cluster_manager.modules: { name: analysis-common } }
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/40_token_filters.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/40_token_filters.yml
index 40c82ff185661..802c79c780689 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/40_token_filters.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/40_token_filters.yml
@@ -127,6 +127,69 @@
     - match:  { tokens.2.token: brown }
     - match:  { tokens.3.token: fox }
 
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter
+                split_on_numerics: false
+                type_table:
+                  - "\\u0023 => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter
+                split_on_numerics: false
+                type_table:
+                  - "# This is a comment"
+                  - "# => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter
+                split_on_numerics: false
+                type_table:
+                  - "# This is a comment"
+                  - "# => ALPHANUM"
+                  - "@ => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
 ---
 "word_delimiter_graph":
     - do:
@@ -231,6 +294,69 @@
     - match:  { detail.tokenfilters.0.tokens.5.end_offset: 19 }
     - match:  { detail.tokenfilters.0.tokens.5.position: 5 }
 
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter_graph
+                split_on_numerics: false
+                type_table:
+                  - "\\u0023 => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter_graph
+                split_on_numerics: false
+                type_table:
+                  - "# This is a comment"
+                  - "# => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
+    - do:
+        indices.analyze:
+          body:
+            text: 'text1 #text2'
+            tokenizer: whitespace
+            filter:
+              - type: word_delimiter_graph
+                split_on_numerics: false
+                type_table:
+                  - "# This is a comment"
+                  - "# => ALPHANUM"
+                  - "@ => ALPHANUM"
+    - length: { tokens: 2 }
+    - match: { tokens.0.token: text1 }
+    - match: { tokens.0.start_offset: 0 }
+    - match: { tokens.0.end_offset: 5 }
+    - match: { tokens.0.position: 0 }
+    - match: { tokens.1.token: "#text2" }
+    - match: { tokens.1.start_offset: 6 }
+    - match: { tokens.1.end_offset: 12 }
+    - match: { tokens.1.position: 1 }
+
 ---
 "unique":
     - do:
@@ -1198,6 +1324,46 @@
     - match:  { tokens.0.token: foo }
 
 ---
+"delimited_term_freq":
+  - skip:
+      version: " - 2.9.99"
+      reason: "delimited_term_freq token filter was added in v2.10.0"
+  - do:
+      indices.create:
+        index: test
+        body:
+          settings:
+            analysis:
+              filter:
+                my_delimited_term_freq:
+                  type: delimited_term_freq
+                  delimiter: ^
+  - do:
+      indices.analyze:
+        index: test
+        body:
+          text:       foo^3
+          tokenizer:  keyword
+          filter:     [my_delimited_term_freq]
+          attributes: termFrequency
+          explain:    true
+  - length: { detail.tokenfilters: 1 }
+  - match:  { detail.tokenfilters.0.tokens.0.token: foo }
+  - match:  { detail.tokenfilters.0.tokens.0.termFrequency: 3 }
+
+  # Test pre-configured token filter too:
+  - do:
+      indices.analyze:
+        body:
+          text:       foo|100
+          tokenizer:  keyword
+          filter:     [delimited_term_freq]
+          attributes: termFrequency
+          explain:    true
+  - length: { detail.tokenfilters: 1 }
+  - match:  { detail.tokenfilters.0.tokens.0.token: foo }
+  - match:  { detail.tokenfilters.0.tokens.0.termFrequency: 100 }
+---
 "keep_filter":
     - do:
         indices.create:
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/50_char_filters.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/50_char_filters.yml
index 67e68428c07c7..5e266c10cba8f 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/50_char_filters.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/50_char_filters.yml
@@ -57,3 +57,22 @@
     - match:  { detail.tokenizer.tokens.0.start_offset: 0 }
     - match:  { detail.tokenizer.tokens.0.end_offset: 15 }
     - match:  { detail.tokenizer.tokens.0.position: 0 }
+---
+"mapping_with_hashtag":
+  - do:
+      indices.analyze:
+        body:
+          text: 'test #test @test'
+          tokenizer: standard
+          filter:
+            - lowercase
+          char_filter:
+            - type: mapping
+              mappings:
+                - "# This is a comment"
+                - "# => _hashsign_"
+                - "@ => _atsign_"
+  - length: { tokens: 3 }
+  - match: { tokens.0.token: test }
+  - match: { tokens.1.token: _hashsign_test }
+  - match: { tokens.2.token: _atsign_test }
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/60_analysis_scripting.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/60_analysis_scripting.yml
index 2015fe31fccb5..1637c8736134f 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/60_analysis_scripting.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/analysis-common/60_analysis_scripting.yml
@@ -68,4 +68,3 @@
     - match: { tokens.1.token: "f" }
     - match: { tokens.2.token: "g" }
     - match: { tokens.3.token: "h" }
-
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_analysis_stats.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_analysis_stats.yml
index a19a1f2721910..5468da5216bb4 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_analysis_stats.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_analysis_stats.yml
@@ -119,4 +119,3 @@
   - match: { indices.analysis.built_in_analyzers.2.name: spanish }
   - match: { indices.analysis.built_in_analyzers.2.count: 2 }
   - match: { indices.analysis.built_in_analyzers.2.index_count: 2 }
-
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/indices.analyze/10_synonyms.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/indices.analyze/10_synonyms.yml
index f0f8765ab5130..42d1c23001300 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/indices.analyze/10_synonyms.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/indices.analyze/10_synonyms.yml
@@ -76,4 +76,3 @@
   - match:  { tokens.5.token: dude }
   - match:  { tokens.5.position: 4 }
   - match:  { tokens.5.positionLength: null }
-
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/60_synonym_graph.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/60_synonym_graph.yml
index ae039e453be6c..4388de3eef30a 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/60_synonym_graph.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/60_synonym_graph.yml
@@ -229,4 +229,3 @@ setup:
                 query: bar baz
                 analyzer: lower_graph_syns
   - match: { hits.total: 1 }
-
diff --git a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/70_intervals.yml b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/70_intervals.yml
index 35a611d13f359..9ad68e960421c 100644
--- a/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/70_intervals.yml
+++ b/modules/analysis-common/src/yamlRestTest/resources/rest-api-spec/test/search.query/70_intervals.yml
@@ -56,4 +56,3 @@ setup:
                         use_field: text_en
                   max_gaps: 1
   - match: { hits.total.value: 1 }
-
diff --git a/modules/build.gradle b/modules/build.gradle
index b493c4a577cec..126bf0c8870ac 100644
--- a/modules/build.gradle
+++ b/modules/build.gradle
@@ -32,7 +32,7 @@ configure(subprojects.findAll { it.parent.path == project.path }) {
   group = 'org.opensearch.plugin' // for modules which publish client jars
   apply plugin: 'opensearch.testclusters'
   apply plugin: 'opensearch.opensearchplugin'
-
+  
   opensearchplugin {
     // for local OpenSearch plugins, the name of the plugin is the same as the directory
     name project.name
diff --git a/modules/geo/build.gradle b/modules/geo/build.gradle
index d78e83ec7c4c6..7ab6f80b65ca2 100644
--- a/modules/geo/build.gradle
+++ b/modules/geo/build.gradle
@@ -28,18 +28,26 @@
  * under the License.
  */
 apply plugin: 'opensearch.yaml-rest-test'
+apply plugin: 'opensearch.internal-cluster-test'
 
 opensearchplugin {
-  description 'Placeholder plugin for geospatial features in OpenSearch. only registers geo_shape field mapper for now'
-  classname 'org.opensearch.geo.GeoPlugin'
+  description 'Plugin for geospatial features in OpenSearch. Registering the geo_shape and aggregations on GeoShape and GeoPoint'
+  classname 'org.opensearch.geo.GeoModulePlugin'
 }
 
 restResources {
   restApi {
-    includeCore '_common', 'indices', 'index', 'search'
+    includeCore '_common', 'indices', 'index', 'search', 'bulk'
   }
 }
+
 artifacts {
   restTests(project.file('src/yamlRestTest/resources/rest-api-spec/test'))
 }
-test.enabled = false
+/**
+ * These compiler arguments needs to be removed, as there are raw types being used in the GeoGrid and GeoTile aggregations.
+ */
+tasks.withType(JavaCompile).configureEach {
+  options.compilerArgs -= '-Xlint:rawtypes'
+  options.compilerArgs -= '-Xlint:unchecked'
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/GeoModulePluginIntegTestCase.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/GeoModulePluginIntegTestCase.java
new file mode 100644
index 0000000000000..c38b29502e282
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/GeoModulePluginIntegTestCase.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.geometry.utils.StandardValidator;
+import org.opensearch.geometry.utils.WellKnownText;
+import org.opensearch.index.mapper.GeoShapeFieldMapper;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+
+/**
+ * This is the base class for all the Geo related integration tests. Use this class to add the features and settings
+ * for the test cluster on which integration tests are running.
+ */
+public abstract class GeoModulePluginIntegTestCase extends ParameterizedOpenSearchIntegTestCase {
+
+    protected static final double GEOHASH_TOLERANCE = 1E-5D;
+
+    protected static final WellKnownText WKT = new WellKnownText(true, new StandardValidator(true));
+
+    public GeoModulePluginIntegTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    /**
+     * Returns a collection of plugins that should be loaded on each node for doing the integration tests. As this
+     * geo plugin is not getting packaged in a zip, we need to load it before the tests run.
+     *
+     * @return List of {@link Plugin}
+     */
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Collections.singletonList(GeoModulePlugin.class);
+    }
+
+    /**
+     * This was added as a backdoor to Mock the implementation of {@link GeoShapeFieldMapper} which was coming from
+     * {@link GeoModulePlugin}. Mock implementation is {@link TestGeoShapeFieldMapperPlugin}. Now we are using the
+     * {@link GeoModulePlugin} in our integration tests we need to override this functionality to avoid multiple mapper
+     * error.
+     *
+     * @return boolean
+     */
+    @Override
+    protected boolean addMockGeoShapeFieldMapper() {
+        return false;
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/MissingValueIT.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/MissingValueIT.java
new file mode 100644
index 0000000000000..7344903fd5220
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/MissingValueIT.java
@@ -0,0 +1,161 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.geo.GeoModulePluginIntegTestCase;
+import org.opensearch.geo.search.aggregations.common.GeoBoundsHelper;
+import org.opensearch.geo.search.aggregations.metrics.GeoBounds;
+import org.opensearch.geo.tests.common.AggregationBuilders;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.geo.tests.common.RandomGeoGeometryGenerator;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.utils.WellKnownText;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.hamcrest.MatcherAssert;
+import org.junit.Before;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.closeTo;
+
+/**
+ * Tests to validate if user specified a missingValue in the input while doing the aggregation
+ */
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class MissingValueIT extends GeoModulePluginIntegTestCase {
+
+    private static final String INDEX_NAME = "idx";
+    private static final String GEO_SHAPE_FIELD_NAME = "myshape";
+    private static final String GEO_SHAPE_FIELD_TYPE = "type=geo_shape";
+    private static final String AGGREGATION_NAME = "bounds";
+    private static final String NON_EXISTENT_FIELD = "non_existing_field";
+    private static final WellKnownText WKT = WellKnownText.INSTANCE;
+    private static Geometry indexedGeometry;
+    private static GeoPoint indexedGeoPoint;
+    private GeoPoint bottomRight;
+    private GeoPoint topLeft;
+
+    public MissingValueIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    protected void setupSuiteScopeCluster() throws Exception {
+        assertAcked(
+            prepareCreate(INDEX_NAME).setMapping(
+                "date",
+                "type=date",
+                "location",
+                "type=geo_point",
+                "str",
+                "type=keyword",
+                GEO_SHAPE_FIELD_NAME,
+                GEO_SHAPE_FIELD_TYPE
+            ).get()
+        );
+        indexedGeometry = RandomGeoGeometryGenerator.randomGeometry(random());
+        indexedGeoPoint = RandomGeoGenerator.randomPoint(random());
+        assert indexedGeometry != null;
+        indexRandom(
+            true,
+            client().prepareIndex(INDEX_NAME).setId("1").setSource(),
+            client().prepareIndex(INDEX_NAME)
+                .setId("2")
+                .setSource(
+                    "str",
+                    "foo",
+                    "long",
+                    3L,
+                    "double",
+                    5.5,
+                    "date",
+                    "2015-05-07",
+                    "location",
+                    indexedGeoPoint.toString(),
+                    GEO_SHAPE_FIELD_NAME,
+                    WKT.toWKT(indexedGeometry)
+                )
+        );
+    }
+
+    @Before
+    public void runBeforeEachTest() {
+        bottomRight = new GeoPoint(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
+        topLeft = new GeoPoint(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
+    }
+
+    public void testUnmappedGeoBounds() {
+        final GeoPoint missingGeoPoint = RandomGeoGenerator.randomPoint(random());
+        GeoBoundsHelper.updateBoundsBottomRight(missingGeoPoint, bottomRight);
+        GeoBoundsHelper.updateBoundsTopLeft(missingGeoPoint, topLeft);
+        SearchResponse response = client().prepareSearch(INDEX_NAME)
+            .addAggregation(
+                AggregationBuilders.geoBounds(AGGREGATION_NAME)
+                    .field(NON_EXISTENT_FIELD)
+                    .wrapLongitude(false)
+                    .missing(missingGeoPoint.toString())
+            )
+            .get();
+        assertSearchResponse(response);
+        validateResult(response.getAggregations().get(AGGREGATION_NAME));
+    }
+
+    public void testGeoBounds() {
+        GeoBoundsHelper.updateBoundsForGeoPoint(indexedGeoPoint, topLeft, bottomRight);
+        final GeoPoint missingGeoPoint = RandomGeoGenerator.randomPoint(random());
+        GeoBoundsHelper.updateBoundsForGeoPoint(missingGeoPoint, topLeft, bottomRight);
+        SearchResponse response = client().prepareSearch(INDEX_NAME)
+            .addAggregation(
+                AggregationBuilders.geoBounds(AGGREGATION_NAME).field("location").wrapLongitude(false).missing(missingGeoPoint.toString())
+            )
+            .get();
+        assertSearchResponse(response);
+        validateResult(response.getAggregations().get(AGGREGATION_NAME));
+    }
+
+    public void testGeoBoundsWithMissingShape() {
+        // create GeoBounds for the indexed Field
+        GeoBoundsHelper.updateBoundsForGeometry(indexedGeometry, topLeft, bottomRight);
+        final Geometry missingGeometry = RandomGeoGeometryGenerator.randomGeometry(random());
+        assert missingGeometry != null;
+        GeoBoundsHelper.updateBoundsForGeometry(missingGeometry, topLeft, bottomRight);
+        final SearchResponse response = client().prepareSearch(INDEX_NAME)
+            .addAggregation(
+                AggregationBuilders.geoBounds(AGGREGATION_NAME)
+                    .wrapLongitude(false)
+                    .field(GEO_SHAPE_FIELD_NAME)
+                    .missing(WKT.toWKT(missingGeometry))
+            )
+            .get();
+        assertSearchResponse(response);
+        validateResult(response.getAggregations().get(AGGREGATION_NAME));
+    }
+
+    public void testUnmappedGeoBoundsOnGeoShape() {
+        // We cannot useGeometry other than Point as for GeoBoundsAggregation as the Default Value for the
+        // CoreValueSourceType is GeoPoint hence we need to use Point here.
+        final Geometry missingGeometry = RandomGeoGeometryGenerator.randomPoint(random());
+        final SearchResponse response = client().prepareSearch(INDEX_NAME)
+            .addAggregation(AggregationBuilders.geoBounds(AGGREGATION_NAME).field(NON_EXISTENT_FIELD).missing(WKT.toWKT(missingGeometry)))
+            .get();
+        GeoBoundsHelper.updateBoundsForGeometry(missingGeometry, topLeft, bottomRight);
+        assertSearchResponse(response);
+        validateResult(response.getAggregations().get(AGGREGATION_NAME));
+    }
+
+    private void validateResult(final GeoBounds bounds) {
+        MatcherAssert.assertThat(bounds.bottomRight().lat(), closeTo(bottomRight.lat(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(bounds.bottomRight().lon(), closeTo(bottomRight.lon(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(bounds.topLeft().lat(), closeTo(topLeft.lat(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(bounds.topLeft().lon(), closeTo(topLeft.lon(), GEOHASH_TOLERANCE));
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/AbstractGeoBucketAggregationIntegTest.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/AbstractGeoBucketAggregationIntegTest.java
new file mode 100644
index 0000000000000..86d8ad2968e7f
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/AbstractGeoBucketAggregationIntegTest.java
@@ -0,0 +1,275 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.apache.lucene.geo.GeoEncodingUtils;
+import org.opensearch.Version;
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.geo.GeoModulePluginIntegTestCase;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.geo.tests.common.RandomGeoGeometryGenerator;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.test.VersionUtils;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+/**
+ * This is the base class for all the Bucket Aggregation related integration tests. Use this class to add common
+ * methods which can be used across different bucket aggregations. If there is any common code that can be used
+ * across other integration test too then this is not the class. Use {@link GeoModulePluginIntegTestCase}
+ */
+public abstract class AbstractGeoBucketAggregationIntegTest extends GeoModulePluginIntegTestCase {
+
+    protected static final int MAX_PRECISION_FOR_GEO_SHAPES_AGG_TESTING = 2;
+
+    protected static final int MIN_PRECISION_WITHOUT_BB_AGGS = 2;
+
+    protected static final int NUM_DOCS = 100;
+
+    protected static final String GEO_SHAPE_INDEX_NAME = "geoshape_index";
+
+    protected static Rectangle boundingRectangleForGeoShapesAgg;
+
+    protected static Map<String, Integer> expectedDocsCountForGeoShapes;
+
+    protected static Map<String, Integer> expectedDocCountsForSingleGeoPoint;
+
+    protected static Map<String, Integer> multiValuedExpectedDocCountsGeoPoint;
+
+    protected static final String GEO_SHAPE_FIELD_NAME = "location_geo_shape";
+
+    protected static final String GEO_POINT_FIELD_NAME = "location";
+
+    protected static final String KEYWORD_FIELD_NAME = "city";
+
+    protected static String smallestGeoHash = null;
+
+    protected final Version version = VersionUtils.randomIndexCompatibleVersion(random());
+
+    public AbstractGeoBucketAggregationIntegTest(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    protected boolean forbidPrivateIndexSettings() {
+        return false;
+    }
+
+    /**
+     * Prepares a GeoShape index for testing the GeoShape bucket aggregations. Different bucket aggregations can use
+     * different techniques for creating buckets. Override the method
+     * {@link AbstractGeoBucketAggregationIntegTest#generateBucketsForGeometry} in the test class for creating the
+     * buckets which will then be used for verifications.
+     *
+     * @param random {@link Random}
+     * @throws Exception thrown during index creation.
+     */
+    protected void prepareGeoShapeIndexForAggregations(final Random random) throws Exception {
+        expectedDocsCountForGeoShapes = new HashMap<>();
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, version).build();
+        final List<IndexRequestBuilder> geoshapes = new ArrayList<>();
+        assertAcked(prepareCreate(GEO_SHAPE_INDEX_NAME).setSettings(settings).setMapping(GEO_SHAPE_FIELD_NAME, "type" + "=geo_shape"));
+        boolean isShapeIntersectingBB = false;
+        for (int i = 0; i < NUM_DOCS;) {
+            final Geometry geometry = RandomGeoGeometryGenerator.randomGeometry(random);
+            final GeoShapeDocValue geometryDocValue = GeoShapeDocValue.createGeometryDocValue(geometry);
+            // make sure that there is 1 shape is intersecting with the bounding box
+            if (!isShapeIntersectingBB) {
+                isShapeIntersectingBB = geometryDocValue.isIntersectingRectangle(boundingRectangleForGeoShapesAgg);
+                if (!isShapeIntersectingBB && i == NUM_DOCS - 1) {
+                    continue;
+                }
+            }
+
+            i++;
+            final Set<String> values = generateBucketsForGeometry(geometry, geometryDocValue);
+            geoshapes.add(indexGeoShape(GEO_SHAPE_INDEX_NAME, geometry));
+            for (final String hash : values) {
+                expectedDocsCountForGeoShapes.put(hash, expectedDocsCountForGeoShapes.getOrDefault(hash, 0) + 1);
+            }
+        }
+        indexRandom(true, geoshapes);
+        ensureGreen(GEO_SHAPE_INDEX_NAME);
+    }
+
+    /**
+     * Returns a set of buckets for the shape at different precision level. Override this method for different bucket
+     * aggregations.
+     *
+     * @param geometry         {@link Geometry}
+     * @param geoShapeDocValue {@link GeoShapeDocValue}
+     * @return A {@link Set} of {@link String} which represents the buckets.
+     */
+    protected abstract Set<String> generateBucketsForGeometry(final Geometry geometry, final GeoShapeDocValue geoShapeDocValue);
+
+    /**
+     * Prepares a GeoPoint index for testing the GeoPoint bucket aggregations. Different bucket aggregations can use
+     * different techniques for creating buckets. Override the method
+     * {@link AbstractGeoBucketAggregationIntegTest#generateBucketsForGeoPoint} in the test class for creating the
+     * buckets which will then be used for verifications.
+     *
+     * @param random {@link Random}
+     * @throws Exception thrown during index creation.
+     */
+    protected void prepareSingleValueGeoPointIndex(final Random random) throws Exception {
+        expectedDocCountsForSingleGeoPoint = new HashMap<>();
+        createIndex("idx_unmapped");
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, version)
+            .put("index.number_of_shards", 4)
+            .put("index.number_of_replicas", 0)
+            .build();
+        assertAcked(
+            prepareCreate("idx").setSettings(settings)
+                .setMapping(GEO_POINT_FIELD_NAME, "type=geo_point", KEYWORD_FIELD_NAME, "type=keyword")
+        );
+        final List<IndexRequestBuilder> cities = new ArrayList<>();
+        for (int i = 0; i < NUM_DOCS; i++) {
+            // generate random point
+            final GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random);
+            cities.add(indexGeoPoint("idx", geoPoint.toString(), geoPoint.getLat() + ", " + geoPoint.getLon()));
+            final Set<String> buckets = generateBucketsForGeoPoint(geoPoint);
+            for (final String bucket : buckets) {
+                expectedDocCountsForSingleGeoPoint.put(bucket, expectedDocCountsForSingleGeoPoint.getOrDefault(bucket, 0) + 1);
+            }
+        }
+        indexRandom(true, cities);
+        ensureGreen("idx_unmapped", "idx");
+    }
+
+    protected void prepareMultiValuedGeoPointIndex(final Random random) throws Exception {
+        multiValuedExpectedDocCountsGeoPoint = new HashMap<>();
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, version).build();
+        final List<IndexRequestBuilder> cities = new ArrayList<>();
+        assertAcked(
+            prepareCreate("multi_valued_idx").setSettings(settings)
+                .setMapping(GEO_POINT_FIELD_NAME, "type=geo_point", KEYWORD_FIELD_NAME, "type=keyword")
+        );
+        for (int i = 0; i < NUM_DOCS; i++) {
+            final int numPoints = random.nextInt(4);
+            final List<String> points = new ArrayList<>();
+            final Set<String> buckets = new HashSet<>();
+            for (int j = 0; j < numPoints; ++j) {
+                // generate random point
+                final GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random);
+                points.add(geoPoint.getLat() + "," + geoPoint.getLon());
+                buckets.addAll(generateBucketsForGeoPoint(geoPoint));
+            }
+            cities.add(indexGeoPoints("multi_valued_idx", Integer.toString(i), points));
+            for (final String bucket : buckets) {
+                multiValuedExpectedDocCountsGeoPoint.put(bucket, multiValuedExpectedDocCountsGeoPoint.getOrDefault(bucket, 0) + 1);
+            }
+        }
+        indexRandom(true, cities);
+        ensureGreen("multi_valued_idx");
+    }
+
+    /**
+     * Returns a set of buckets for the GeoPoint at different precision level. Override this method for different bucket
+     * aggregations.
+     *
+     * @param geoPoint {@link GeoPoint}
+     * @return A {@link Set} of {@link String} which represents the buckets.
+     */
+    protected abstract Set<String> generateBucketsForGeoPoint(final GeoPoint geoPoint);
+
+    /**
+     * Indexes a GeoShape in the provided index.
+     * @param index {@link String} index name
+     * @param geometry {@link Geometry} the Geometry to be indexed
+     * @return {@link IndexRequestBuilder}
+     * @throws Exception thrown during creation of {@link IndexRequestBuilder}
+     */
+    protected IndexRequestBuilder indexGeoShape(final String index, final Geometry geometry) throws Exception {
+        XContentBuilder source = jsonBuilder().startObject();
+        source = source.field(GEO_SHAPE_FIELD_NAME, WKT.toWKT(geometry));
+        source = source.endObject();
+        return client().prepareIndex(index).setSource(source);
+    }
+
+    /**
+     * Indexes a {@link List} of {@link GeoPoint}s in the provided Index name.
+     * @param index {@link String} index name
+     * @param name {@link String} value for the string field in index
+     * @param latLon {@link List} of {@link String} representing the String representation of GeoPoint
+     * @return {@link IndexRequestBuilder}
+     * @throws Exception thrown during indexing.
+     */
+    protected IndexRequestBuilder indexGeoPoints(final String index, final String name, final List<String> latLon) throws Exception {
+        XContentBuilder source = jsonBuilder().startObject().field(KEYWORD_FIELD_NAME, name);
+        if (latLon != null) {
+            source = source.field(GEO_POINT_FIELD_NAME, latLon);
+        }
+        source = source.endObject();
+        return client().prepareIndex(index).setSource(source);
+    }
+
+    /**
+     * Indexes a {@link GeoPoint} in the provided Index name.
+     * @param index {@link String} index name
+     * @param name {@link String} value for the string field in index
+     * @param latLon {@link String} representing the String representation of GeoPoint
+     * @return {@link IndexRequestBuilder}
+     * @throws Exception thrown during indexing.
+     */
+    protected IndexRequestBuilder indexGeoPoint(final String index, final String name, final String latLon) throws Exception {
+        return indexGeoPoints(index, name, List.of(latLon));
+    }
+
+    /**
+     * Generates a Bounding Box of a fixed radius that can be used for shapes aggregations to reduce the size of
+     * aggregation results.
+     * @param random {@link Random}
+     * @return {@link Rectangle}
+     */
+    protected Rectangle getGridAggregationBoundingBox(final Random random) {
+        final double radius = getRadiusOfBoundingBox();
+        assertTrue("The radius of Bounding Box is less than or equal to 0", radius > 0);
+        return RandomGeoGeometryGenerator.randomRectangle(random, radius);
+    }
+
+    /**
+     * Returns a radius for the Bounding box. Test classes can override this method to change the radius of BBox for
+     * the test cases. If we increase this value, it will lead to creation of a lot of buckets that can lead of
+     * IndexOutOfBoundsExceptions.
+     * @return double
+     */
+    protected double getRadiusOfBoundingBox() {
+        return 5.0;
+    }
+
+    /**
+     * Encode and Decode the {@link GeoPoint} to get a {@link GeoPoint} which has the exact precision which is being
+     * stored.
+     * @param geoPoint {@link GeoPoint}
+     * @return {@link GeoPoint}
+     */
+    protected GeoPoint toStoragePrecision(final GeoPoint geoPoint) {
+        return new GeoPoint(
+            GeoEncodingUtils.decodeLatitude(GeoEncodingUtils.encodeLatitude(geoPoint.getLat())),
+            GeoEncodingUtils.decodeLongitude(GeoEncodingUtils.encodeLongitude(geoPoint.getLon()))
+        );
+    }
+
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridIT.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridIT.java
new file mode 100644
index 0000000000000..4048bb62f8818
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridIT.java
@@ -0,0 +1,327 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGrid;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.common.GeoBoundsHelper;
+import org.opensearch.geo.tests.common.AggregationBuilders;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.geometry.utils.Geohash;
+import org.opensearch.index.query.GeoBoundingBoxQueryBuilder;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.bucket.filter.Filter;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+
+import static org.opensearch.geometry.utils.Geohash.PRECISION;
+import static org.opensearch.geometry.utils.Geohash.stringEncode;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class GeoHashGridIT extends AbstractGeoBucketAggregationIntegTest {
+
+    private static final String AGG_NAME = "geohashgrid";
+
+    public GeoHashGridIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        Random random = random();
+        // Creating a BB for limiting the number buckets generated during aggregation
+        boundingRectangleForGeoShapesAgg = getGridAggregationBoundingBox(random);
+        expectedDocCountsForSingleGeoPoint = new HashMap<>();
+        prepareSingleValueGeoPointIndex(random);
+        prepareMultiValuedGeoPointIndex(random);
+        prepareGeoShapeIndexForAggregations(random);
+    }
+
+    public void testSimple() {
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            List<? extends GeoGrid.Bucket> buckets = geoGrid.getBuckets();
+            Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
+            Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
+            for (int i = 0; i < buckets.size(); i++) {
+                GeoGrid.Bucket cell = buckets.get(i);
+                String geohash = cell.getKeyAsString();
+
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = expectedDocCountsForSingleGeoPoint.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+                GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
+                assertThat(stringEncode(geoPoint.lon(), geoPoint.lat(), precision), equalTo(geohash));
+                assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
+            }
+        }
+    }
+
+    public void testGeoShapes() {
+        final GeoBoundingBox boundingBox = new GeoBoundingBox(
+            new GeoPoint(boundingRectangleForGeoShapesAgg.getMaxLat(), boundingRectangleForGeoShapesAgg.getMinLon()),
+            new GeoPoint(boundingRectangleForGeoShapesAgg.getMinLat(), boundingRectangleForGeoShapesAgg.getMaxLon())
+        );
+        for (int precision = 1; precision <= MAX_PRECISION_FOR_GEO_SHAPES_AGG_TESTING; precision++) {
+            GeoGridAggregationBuilder builder = AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_SHAPE_FIELD_NAME).precision(precision);
+            // This makes sure that for only higher precision we are providing the GeoBounding Box. This also ensures
+            // that we are able to test both bounded and unbounded aggregations
+            if (precision > MIN_PRECISION_WITHOUT_BB_AGGS) {
+                builder.setGeoBoundingBox(boundingBox);
+            }
+            final SearchResponse response = client().prepareSearch(GEO_SHAPE_INDEX_NAME).addAggregation(builder).get();
+            final GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            final List<? extends GeoGrid.Bucket> buckets = geoGrid.getBuckets();
+            final Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
+            final Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
+            for (int i = 0; i < buckets.size(); i++) {
+                final GeoGrid.Bucket cell = buckets.get(i);
+                final String geohash = cell.getKeyAsString();
+
+                final long bucketCount = cell.getDocCount();
+                final int expectedBucketCount = expectedDocsCountForGeoShapes.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+                final GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
+                assertThat(stringEncode(geoPoint.lon(), geoPoint.lat(), precision), equalTo(geohash));
+                assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
+            }
+        }
+    }
+
+    public void testMultivalued() {
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("multi_valued_idx")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+            assertSearchResponse(response);
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
+                String geohash = cell.getKeyAsString();
+
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = multiValuedExpectedDocCountsGeoPoint.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+            }
+        }
+    }
+
+    public void testFiltered() {
+        GeoBoundingBoxQueryBuilder bbox = new GeoBoundingBoxQueryBuilder(GEO_POINT_FIELD_NAME);
+        bbox.setCorners(smallestGeoHash).queryName("bbox");
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx")
+                .addAggregation(
+                    org.opensearch.search.aggregations.AggregationBuilders.filter("filtered", bbox)
+                        .subAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                )
+                .get();
+
+            assertSearchResponse(response);
+
+            Filter filter = response.getAggregations().get("filtered");
+
+            GeoGrid geoGrid = filter.getAggregations().get(AGG_NAME);
+            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
+                String geohash = cell.getKeyAsString();
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = expectedDocCountsForSingleGeoPoint.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertTrue("Buckets must be filtered", geohash.startsWith(smallestGeoHash));
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+
+            }
+        }
+    }
+
+    public void testUnmapped() {
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx_unmapped")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            assertThat(geoGrid.getBuckets().size(), equalTo(0));
+        }
+
+    }
+
+    public void testPartiallyUnmapped() {
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx", "idx_unmapped")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
+                String geohash = cell.getKeyAsString();
+
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = expectedDocCountsForSingleGeoPoint.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+            }
+        }
+    }
+
+    public void testTopMatch() {
+        for (int precision = 1; precision <= PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx")
+                .addAggregation(
+                    AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).size(1).shardSize(100).precision(precision)
+                )
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            // Check we only have one bucket with the best match for that resolution
+            assertThat(geoGrid.getBuckets().size(), equalTo(1));
+            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
+                String geohash = cell.getKeyAsString();
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = 0;
+                for (var cursor : expectedDocCountsForSingleGeoPoint.entrySet()) {
+                    if (cursor.getKey().length() == precision) {
+                        expectedBucketCount = Math.max(expectedBucketCount, cursor.getValue());
+                    }
+                }
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+            }
+        }
+    }
+
+    public void testSizeIsZero() {
+        final int size = 0;
+        final int shardSize = 10000;
+        IllegalArgumentException exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().prepareSearch("idx")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).size(size).shardSize(shardSize))
+                .get()
+        );
+        assertThat(exception.getMessage(), containsString("[size] must be greater than 0. Found [0] in [" + AGG_NAME + "]"));
+    }
+
+    public void testShardSizeIsZero() {
+        final int size = 100;
+        final int shardSize = 0;
+        IllegalArgumentException exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().prepareSearch("idx")
+                .addAggregation(AggregationBuilders.geohashGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).size(size).shardSize(shardSize))
+                .get()
+        );
+        assertThat(exception.getMessage(), containsString("[shardSize] must be greater than 0. Found [0] in [" + AGG_NAME + "]"));
+    }
+
+    @Override
+    protected Set<String> generateBucketsForGeometry(final Geometry geometry, final GeoShapeDocValue geometryDocValue) {
+        final GeoPoint topLeft = new GeoPoint();
+        final GeoPoint bottomRight = new GeoPoint();
+        assert geometry != null;
+        GeoBoundsHelper.updateBoundsForGeometry(geometry, topLeft, bottomRight);
+        final Set<String> geoHashes = new HashSet<>();
+        final boolean isIntersectingWithBoundingRectangle = geometryDocValue.isIntersectingRectangle(boundingRectangleForGeoShapesAgg);
+        for (int precision = MAX_PRECISION_FOR_GEO_SHAPES_AGG_TESTING; precision > 0; precision--) {
+            if (precision > MIN_PRECISION_WITHOUT_BB_AGGS && isIntersectingWithBoundingRectangle == false) {
+                continue;
+            }
+            final GeoPoint topRight = new GeoPoint(topLeft.getLat(), bottomRight.getLon());
+            String currentGeoHash = Geohash.stringEncode(topLeft.getLon(), topLeft.getLat(), precision);
+            String startingRowGeoHash = currentGeoHash;
+            String endGeoHashForCurrentRow = Geohash.stringEncode(topRight.getLon(), topRight.getLat(), precision);
+            String terminatingGeoHash = Geohash.stringEncode(bottomRight.getLon(), bottomRight.getLat(), precision);
+            while (true) {
+                final Rectangle currentRectangle = Geohash.toBoundingBox(currentGeoHash);
+                if (geometryDocValue.isIntersectingRectangle(currentRectangle)) {
+                    geoHashes.add(currentGeoHash);
+                }
+                assert currentGeoHash != null;
+                if (currentGeoHash.equals(terminatingGeoHash)) {
+                    break;
+                }
+                if (currentGeoHash.equals(endGeoHashForCurrentRow)) {
+                    // move in south direction
+                    currentGeoHash = Geohash.getNeighbor(startingRowGeoHash, precision, 0, -1);
+                    startingRowGeoHash = currentGeoHash;
+                    endGeoHashForCurrentRow = Geohash.getNeighbor(endGeoHashForCurrentRow, precision, 0, -1);
+                } else {
+                    // move in East direction
+                    currentGeoHash = Geohash.getNeighbor(currentGeoHash, precision, 1, 0);
+                }
+            }
+        }
+        return geoHashes;
+    }
+
+    @Override
+    protected Set<String> generateBucketsForGeoPoint(final GeoPoint geoPoint) {
+        Set<String> buckets = new HashSet<>();
+        for (int precision = PRECISION; precision > 0; precision--) {
+            final String hash = Geohash.stringEncode(geoPoint.getLon(), geoPoint.getLat(), precision);
+            if ((smallestGeoHash == null) || (hash.length() < smallestGeoHash.length())) {
+                smallestGeoHash = hash;
+            }
+            buckets.add(hash);
+        }
+        return buckets;
+    }
+
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridIT.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridIT.java
new file mode 100644
index 0000000000000..2a5772d417530
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridIT.java
@@ -0,0 +1,174 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGrid;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.common.GeoBoundsHelper;
+import org.opensearch.geo.tests.common.AggregationBuilders;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.hamcrest.MatcherAssert;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class GeoTileGridIT extends AbstractGeoBucketAggregationIntegTest {
+
+    private static final int GEOPOINT_MAX_PRECISION = 17;
+
+    private static final String AGG_NAME = "geotilegrid";
+
+    public GeoTileGridIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        final Random random = random();
+        // Creating a BB for limiting the number buckets generated during aggregation
+        boundingRectangleForGeoShapesAgg = getGridAggregationBoundingBox(random);
+        prepareSingleValueGeoPointIndex(random);
+        prepareMultiValuedGeoPointIndex(random);
+        prepareGeoShapeIndexForAggregations(random);
+        ensureSearchable();
+    }
+
+    public void testGeoShapes() {
+        final GeoBoundingBox boundingBox = new GeoBoundingBox(
+            new GeoPoint(boundingRectangleForGeoShapesAgg.getMaxLat(), boundingRectangleForGeoShapesAgg.getMinLon()),
+            new GeoPoint(boundingRectangleForGeoShapesAgg.getMinLat(), boundingRectangleForGeoShapesAgg.getMaxLon())
+        );
+        for (int precision = 1; precision <= MAX_PRECISION_FOR_GEO_SHAPES_AGG_TESTING; precision++) {
+            final GeoGridAggregationBuilder builder = AggregationBuilders.geotileGrid(AGG_NAME)
+                .field(GEO_SHAPE_FIELD_NAME)
+                .precision(precision);
+            // This makes sure that for only higher precision we are providing the GeoBounding Box. This also ensures
+            // that we are able to test both bounded and unbounded aggregations
+            if (precision > MIN_PRECISION_WITHOUT_BB_AGGS) {
+                builder.setGeoBoundingBox(boundingBox);
+            }
+            final SearchResponse response = client().prepareSearch(GEO_SHAPE_INDEX_NAME).addAggregation(builder).get();
+            final GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            final List<? extends GeoGrid.Bucket> buckets = geoGrid.getBuckets();
+            final Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
+            final Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
+            for (int i = 0; i < buckets.size(); i++) {
+                final GeoGrid.Bucket cell = buckets.get(i);
+                final String geoTile = cell.getKeyAsString();
+
+                final long bucketCount = cell.getDocCount();
+                final int expectedBucketCount = expectedDocsCountForGeoShapes.get(geoTile);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geotile " + geoTile + " has wrong doc count ", expectedBucketCount, bucketCount);
+                final GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
+                MatcherAssert.assertThat(GeoTileUtils.stringEncode(geoPoint.lon(), geoPoint.lat(), precision), equalTo(geoTile));
+                MatcherAssert.assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
+            }
+        }
+    }
+
+    public void testSimpleGeoPointsAggregation() {
+        for (int precision = 1; precision <= GEOPOINT_MAX_PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("idx")
+                .addAggregation(AggregationBuilders.geotileGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            List<? extends GeoGrid.Bucket> buckets = geoGrid.getBuckets();
+            Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
+            Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
+            for (int i = 0; i < buckets.size(); i++) {
+                GeoGrid.Bucket cell = buckets.get(i);
+                String geoTile = cell.getKeyAsString();
+
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = expectedDocCountsForSingleGeoPoint.get(geoTile);
+                assertNotSame(bucketCount, 0);
+                assertEquals("GeoTile " + geoTile + " has wrong doc count ", expectedBucketCount, bucketCount);
+                GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
+                assertThat(GeoTileUtils.stringEncode(geoPoint.lon(), geoPoint.lat(), precision), equalTo(geoTile));
+                assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
+            }
+        }
+    }
+
+    public void testMultivaluedGeoPointsAggregation() throws Exception {
+        for (int precision = 1; precision <= GEOPOINT_MAX_PRECISION; precision++) {
+            SearchResponse response = client().prepareSearch("multi_valued_idx")
+                .addAggregation(AggregationBuilders.geotileGrid(AGG_NAME).field(GEO_POINT_FIELD_NAME).precision(precision))
+                .get();
+
+            assertSearchResponse(response);
+
+            GeoGrid geoGrid = response.getAggregations().get(AGG_NAME);
+            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
+                String geohash = cell.getKeyAsString();
+
+                long bucketCount = cell.getDocCount();
+                int expectedBucketCount = multiValuedExpectedDocCountsGeoPoint.get(geohash);
+                assertNotSame(bucketCount, 0);
+                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
+            }
+        }
+    }
+
+    /**
+     * Returns a set of buckets for the shape at different precision level. Override this method for different bucket
+     * aggregations.
+     *
+     * @param geometry         {@link Geometry}
+     * @param geoShapeDocValue {@link GeoShapeDocValue}
+     * @return A {@link Set} of {@link String} which represents the buckets.
+     */
+    @Override
+    protected Set<String> generateBucketsForGeometry(final Geometry geometry, final GeoShapeDocValue geoShapeDocValue) {
+        final GeoPoint topLeft = new GeoPoint();
+        final GeoPoint bottomRight = new GeoPoint();
+        assert geometry != null;
+        GeoBoundsHelper.updateBoundsForGeometry(geometry, topLeft, bottomRight);
+        final Set<String> geoTiles = new HashSet<>();
+        final boolean isIntersectingWithBoundingRectangle = geoShapeDocValue.isIntersectingRectangle(boundingRectangleForGeoShapesAgg);
+        for (int precision = MAX_PRECISION_FOR_GEO_SHAPES_AGG_TESTING; precision > 0; precision--) {
+            if (precision > MIN_PRECISION_WITHOUT_BB_AGGS && isIntersectingWithBoundingRectangle == false) {
+                continue;
+            }
+            geoTiles.addAll(
+                GeoTileUtils.encodeShape(geoShapeDocValue, precision).stream().map(GeoTileUtils::stringEncode).collect(Collectors.toSet())
+            );
+        }
+        return geoTiles;
+    }
+
+    protected Set<String> generateBucketsForGeoPoint(final GeoPoint geoPoint) {
+        Set<String> buckets = new HashSet<>();
+        for (int precision = GEOPOINT_MAX_PRECISION; precision > 0; precision--) {
+            final GeoPoint precisedGeoPoint = this.toStoragePrecision(geoPoint);
+            final String tile = GeoTileUtils.stringEncode(precisedGeoPoint.getLon(), precisedGeoPoint.getLat(), precision);
+            buckets.add(tile);
+        }
+        return buckets;
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/ShardReduceIT.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/ShardReduceIT.java
new file mode 100644
index 0000000000000..85541c60f133c
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/bucket/ShardReduceIT.java
@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.geo.GeoModulePluginIntegTestCase;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGrid;
+import org.opensearch.geo.tests.common.AggregationBuilders;
+import org.opensearch.geometry.utils.Geohash;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
+import org.opensearch.search.aggregations.bucket.histogram.Histogram;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.equalTo;
+
+/**
+ * Tests making sure that the reduce is propagated to all aggregations in the hierarchy when executing on a single shard
+ * These tests are based on the date histogram in combination of min_doc_count=0. In order for the date histogram to
+ * compute empty buckets, its {@code reduce()} method must be called. So by adding the date histogram under other buckets,
+ * we can make sure that the reduce is properly propagated by checking that empty buckets were created.
+ */
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class ShardReduceIT extends GeoModulePluginIntegTestCase {
+
+    public ShardReduceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    private IndexRequestBuilder indexDoc(String date, int value) throws Exception {
+        return client().prepareIndex("idx")
+            .setSource(
+                jsonBuilder().startObject()
+                    .field("value", value)
+                    .field("ip", "10.0.0." + value)
+                    .field("location", Geohash.stringEncode(5, 52, Geohash.PRECISION))
+                    .field("date", date)
+                    .field("term-l", 1)
+                    .field("term-d", 1.5)
+                    .field("term-s", "term")
+                    .startObject("nested")
+                    .field("date", date)
+                    .endObject()
+                    .endObject()
+            );
+    }
+
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        assertAcked(
+            prepareCreate("idx").setMapping(
+                "nested",
+                "type=nested",
+                "ip",
+                "type=ip",
+                "location",
+                "type=geo_point",
+                "term-s",
+                "type=keyword"
+            )
+        );
+
+        indexRandom(true, indexDoc("2014-01-01", 1), indexDoc("2014-01-02", 2), indexDoc("2014-01-04", 3));
+        ensureSearchable();
+    }
+
+    public void testGeoHashGrid() throws Exception {
+        SearchResponse response = client().prepareSearch("idx")
+            .setQuery(QueryBuilders.matchAllQuery())
+            .addAggregation(
+                AggregationBuilders.geohashGrid("grid")
+                    .field("location")
+                    .subAggregation(dateHistogram("histo").field("date").fixedInterval(DateHistogramInterval.DAY).minDocCount(0))
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoGrid grid = response.getAggregations().get("grid");
+        Histogram histo = grid.getBuckets().iterator().next().getAggregations().get("histo");
+        assertThat(histo.getBuckets().size(), equalTo(4));
+    }
+
+    public void testGeoTileGrid() throws Exception {
+        SearchResponse response = client().prepareSearch("idx")
+            .setQuery(QueryBuilders.matchAllQuery())
+            .addAggregation(
+                AggregationBuilders.geotileGrid("grid")
+                    .field("location")
+                    .subAggregation(dateHistogram("histo").field("date").fixedInterval(DateHistogramInterval.DAY).minDocCount(0))
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoGrid grid = response.getAggregations().get("grid");
+        Histogram histo = grid.getBuckets().iterator().next().getAggregations().get("histo");
+        assertThat(histo.getBuckets().size(), equalTo(4));
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/common/GeoBoundsHelper.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/common/GeoBoundsHelper.java
new file mode 100644
index 0000000000000..297aa311d5b75
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/common/GeoBoundsHelper.java
@@ -0,0 +1,187 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.common;
+
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.GeometryCollection;
+import org.opensearch.geometry.Line;
+import org.opensearch.geometry.MultiLine;
+import org.opensearch.geometry.MultiPoint;
+import org.opensearch.geometry.MultiPolygon;
+import org.opensearch.geometry.Point;
+import org.opensearch.geometry.Polygon;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.geometry.ShapeType;
+import org.junit.Assert;
+
+import java.util.Locale;
+
+/**
+ * A helper class for finding the geo bounds for a shape or a point.
+ */
+public final class GeoBoundsHelper {
+
+    /**
+     * Updates the GeoBounds for the input GeoPoint in topLeft and bottomRight GeoPoints.
+     *
+     * @param geoPoint {@link GeoPoint}
+     * @param topLeft {@link GeoPoint}
+     * @param bottomRight {@link GeoPoint}
+     */
+    public static void updateBoundsForGeoPoint(final GeoPoint geoPoint, final GeoPoint topLeft, final GeoPoint bottomRight) {
+        updateBoundsBottomRight(geoPoint, bottomRight);
+        updateBoundsTopLeft(geoPoint, topLeft);
+    }
+
+    /**
+     * Find the bottom right for a point and put it in the currentBounds param.
+     *
+     * @param geoPoint {@link GeoPoint}
+     * @param currentBound {@link GeoPoint}
+     */
+    public static void updateBoundsBottomRight(final GeoPoint geoPoint, final GeoPoint currentBound) {
+        if (geoPoint.lat() < currentBound.lat()) {
+            currentBound.resetLat(geoPoint.lat());
+        }
+        if (geoPoint.lon() > currentBound.lon()) {
+            currentBound.resetLon(geoPoint.lon());
+        }
+    }
+
+    /**
+     * Find the top left for a point and put it in the currentBounds param.
+     *
+     * @param geoPoint {@link GeoPoint}
+     * @param currentBound {@link GeoPoint}
+     */
+    public static void updateBoundsTopLeft(final GeoPoint geoPoint, final GeoPoint currentBound) {
+        if (geoPoint.lat() > currentBound.lat()) {
+            currentBound.resetLat(geoPoint.lat());
+        }
+        if (geoPoint.lon() < currentBound.lon()) {
+            currentBound.resetLon(geoPoint.lon());
+        }
+    }
+
+    /**
+     * Find the bounds for an input shape.
+     *
+     * @param geometry {@link Geometry}
+     * @param geoShapeTopLeft {@link GeoPoint}
+     * @param geoShapeBottomRight {@link GeoPoint}
+     */
+    public static void updateBoundsForGeometry(
+        final Geometry geometry,
+        final GeoPoint geoShapeTopLeft,
+        final GeoPoint geoShapeBottomRight
+    ) {
+        final ShapeType shapeType = geometry.type();
+        switch (shapeType) {
+            case POINT:
+                updateBoundsTopLeft((Point) geometry, geoShapeTopLeft);
+                updateBoundsBottomRight((Point) geometry, geoShapeBottomRight);
+                return;
+            case MULTIPOINT:
+                ((MultiPoint) geometry).getAll().forEach(p -> updateBoundsTopLeft(p, geoShapeTopLeft));
+                ((MultiPoint) geometry).getAll().forEach(p -> updateBoundsBottomRight(p, geoShapeBottomRight));
+                return;
+            case POLYGON:
+                updateBoundsTopLeft((Polygon) geometry, geoShapeTopLeft);
+                updateBoundsBottomRight((Polygon) geometry, geoShapeBottomRight);
+                return;
+            case LINESTRING:
+                updateBoundsTopLeft((Line) geometry, geoShapeTopLeft);
+                updateBoundsBottomRight((Line) geometry, geoShapeBottomRight);
+                return;
+            case MULTIPOLYGON:
+                ((MultiPolygon) geometry).getAll().forEach(p -> updateBoundsTopLeft(p, geoShapeTopLeft));
+                ((MultiPolygon) geometry).getAll().forEach(p -> updateBoundsBottomRight(p, geoShapeBottomRight));
+                return;
+            case GEOMETRYCOLLECTION:
+                ((GeometryCollection<?>) geometry).getAll()
+                    .forEach(geo -> updateBoundsForGeometry(geo, geoShapeTopLeft, geoShapeBottomRight));
+                return;
+            case MULTILINESTRING:
+                ((MultiLine) geometry).getAll().forEach(line -> updateBoundsTopLeft(line, geoShapeTopLeft));
+                ((MultiLine) geometry).getAll().forEach(line -> updateBoundsBottomRight(line, geoShapeBottomRight));
+                return;
+            case ENVELOPE:
+                updateBoundsTopLeft((Rectangle) geometry, geoShapeTopLeft);
+                updateBoundsBottomRight((Rectangle) geometry, geoShapeBottomRight);
+                return;
+            default:
+                Assert.fail(String.format(Locale.ROOT, "The shape type %s is not supported", shapeType));
+        }
+    }
+
+    private static void updateBoundsTopLeft(final Point p, final GeoPoint currentBound) {
+        final GeoPoint geoPoint = new GeoPoint(p.getLat(), p.getLon());
+        updateBoundsTopLeft(geoPoint, currentBound);
+    }
+
+    private static void updateBoundsTopLeft(final Polygon polygon, final GeoPoint currentBound) {
+        for (int i = 0; i < polygon.getPolygon().length(); i++) {
+            double lat = polygon.getPolygon().getLats()[i];
+            double lon = polygon.getPolygon().getLons()[i];
+            final GeoPoint geoPoint = new GeoPoint(lat, lon);
+            updateBoundsTopLeft(geoPoint, currentBound);
+        }
+    }
+
+    private static void updateBoundsTopLeft(final Line line, final GeoPoint currentBound) {
+        for (int i = 0; i < line.length(); i++) {
+            double lat = line.getLats()[i];
+            double lon = line.getLons()[i];
+            final GeoPoint geoPoint = new GeoPoint(lat, lon);
+            updateBoundsTopLeft(geoPoint, currentBound);
+        }
+    }
+
+    private static void updateBoundsTopLeft(final Rectangle rectangle, final GeoPoint currentBound) {
+        if (rectangle.getMaxLat() > currentBound.lat()) {
+            currentBound.resetLat(rectangle.getMaxLat());
+        }
+        if (rectangle.getMinLon() < currentBound.lon()) {
+            currentBound.resetLon(rectangle.getMinLon());
+        }
+    }
+
+    private static void updateBoundsBottomRight(final Point p, final GeoPoint currentBound) {
+        final GeoPoint geoPoint = new GeoPoint(p.getLat(), p.getLon());
+        updateBoundsBottomRight(geoPoint, currentBound);
+    }
+
+    private static void updateBoundsBottomRight(final Polygon polygon, final GeoPoint currentBound) {
+        for (int i = 0; i < polygon.getPolygon().length(); i++) {
+            double lat = polygon.getPolygon().getLats()[i];
+            double lon = polygon.getPolygon().getLons()[i];
+            final GeoPoint geoPoint = new GeoPoint(lat, lon);
+            updateBoundsBottomRight(geoPoint, currentBound);
+        }
+    }
+
+    private static void updateBoundsBottomRight(final Line line, final GeoPoint currentBound) {
+        for (int i = 0; i < line.length(); i++) {
+            double lat = line.getLats()[i];
+            double lon = line.getLons()[i];
+            final GeoPoint geoPoint = new GeoPoint(lat, lon);
+            updateBoundsBottomRight(geoPoint, currentBound);
+        }
+    }
+
+    private static void updateBoundsBottomRight(final Rectangle rectangle, final GeoPoint currentBound) {
+        if (rectangle.getMinLat() < currentBound.lat()) {
+            currentBound.resetLat(rectangle.getMinLat());
+        }
+        if (rectangle.getMaxLon() > currentBound.lon()) {
+            currentBound.resetLon(rectangle.getMaxLon());
+        }
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoAggregatorModulePluginTestCase.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoAggregatorModulePluginTestCase.java
new file mode 100644
index 0000000000000..711744b944ce3
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoAggregatorModulePluginTestCase.java
@@ -0,0 +1,294 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.document.DocumentField;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.geo.GeoModulePluginIntegTestCase;
+import org.opensearch.geo.search.aggregations.common.GeoBoundsHelper;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.geo.tests.common.RandomGeoGeometryGenerator;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.utils.Geohash;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.sort.SortBuilders;
+import org.opensearch.search.sort.SortOrder;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.IntStream;
+
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.equalTo;
+
+/**
+ * This is base class for all Geo Aggregations Integration Tests. This class is similar to what we have in the server
+ * folder of the OpenSearch repo. As part of moving the Geo based aggregation into separate module and plugin we need
+ * to copy the code as we cannot depend on this class.
+ * <a href="https://github.com/opensearch-project/geospatial/issues/92">GitHub issue</a>
+ */
+public abstract class AbstractGeoAggregatorModulePluginTestCase extends GeoModulePluginIntegTestCase {
+
+    protected static final String SINGLE_VALUED_FIELD_NAME = "geo_value";
+    protected static final String MULTI_VALUED_FIELD_NAME = "geo_values";
+    protected static final String GEO_SHAPE_FIELD_NAME = "shape";
+    protected static final String NUMBER_FIELD_NAME = "l_values";
+    protected static final String UNMAPPED_IDX_NAME = "idx_unmapped";
+    protected static final String IDX_NAME = "idx";
+    protected static final String EMPTY_IDX_NAME = "empty_idx";
+    protected static final String DATELINE_IDX_NAME = "dateline_idx";
+    protected static final String HIGH_CARD_IDX_NAME = "high_card_idx";
+    protected static final String IDX_ZERO_NAME = "idx_zero";
+
+    protected static int numDocs;
+    protected static int numUniqueGeoPoints;
+    protected static GeoPoint[] singleValues, multiValues;
+    protected static Geometry[] geoShapesValues;
+    protected static GeoPoint singleTopLeft, singleBottomRight, multiTopLeft, multiBottomRight, singleCentroid, multiCentroid,
+        unmappedCentroid, geoShapeTopLeft, geoShapeBottomRight;
+    protected static Map<String, Integer> expectedDocCountsForGeoHash = null;
+    protected static Map<String, GeoPoint> expectedCentroidsForGeoHash = null;
+
+    public AbstractGeoAggregatorModulePluginTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        createIndex(UNMAPPED_IDX_NAME);
+        assertAcked(
+            prepareCreate(IDX_NAME).setMapping(
+                SINGLE_VALUED_FIELD_NAME,
+                "type=geo_point",
+                MULTI_VALUED_FIELD_NAME,
+                "type=geo_point",
+                NUMBER_FIELD_NAME,
+                "type=long",
+                "tag",
+                "type=keyword",
+                GEO_SHAPE_FIELD_NAME,
+                "type=geo_shape"
+            )
+        );
+
+        singleTopLeft = new GeoPoint(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
+        singleBottomRight = new GeoPoint(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
+        multiTopLeft = new GeoPoint(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
+        multiBottomRight = new GeoPoint(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
+        geoShapeTopLeft = new GeoPoint(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
+        geoShapeBottomRight = new GeoPoint(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
+        singleCentroid = new GeoPoint(0, 0);
+        multiCentroid = new GeoPoint(0, 0);
+        unmappedCentroid = new GeoPoint(0, 0);
+
+        numDocs = randomIntBetween(6, 20);
+        numUniqueGeoPoints = randomIntBetween(1, numDocs);
+        expectedDocCountsForGeoHash = new HashMap<>(numDocs * 2);
+        expectedCentroidsForGeoHash = new HashMap<>(numDocs * 2);
+
+        singleValues = new GeoPoint[numUniqueGeoPoints];
+        for (int i = 0; i < singleValues.length; i++) {
+            singleValues[i] = RandomGeoGenerator.randomPoint(random());
+            GeoBoundsHelper.updateBoundsForGeoPoint(singleValues[i], singleTopLeft, singleBottomRight);
+        }
+
+        multiValues = new GeoPoint[numUniqueGeoPoints];
+        for (int i = 0; i < multiValues.length; i++) {
+            multiValues[i] = RandomGeoGenerator.randomPoint(random());
+            GeoBoundsHelper.updateBoundsForGeoPoint(multiValues[i], multiTopLeft, multiBottomRight);
+        }
+
+        geoShapesValues = new Geometry[numDocs];
+        IntStream.range(0, numDocs).forEach(iterator -> {
+            geoShapesValues[iterator] = RandomGeoGeometryGenerator.randomGeometry(random());
+            GeoBoundsHelper.updateBoundsForGeometry(geoShapesValues[iterator], geoShapeTopLeft, geoShapeBottomRight);
+        });
+
+        List<IndexRequestBuilder> builders = new ArrayList<>();
+
+        GeoPoint singleVal;
+        final GeoPoint[] multiVal = new GeoPoint[2];
+        double newMVLat, newMVLon;
+        for (int i = 0; i < numDocs; i++) {
+            singleVal = singleValues[i % numUniqueGeoPoints];
+            multiVal[0] = multiValues[i % numUniqueGeoPoints];
+            multiVal[1] = multiValues[(i + 1) % numUniqueGeoPoints];
+            builders.add(
+                client().prepareIndex(IDX_NAME)
+                    .setSource(
+                        jsonBuilder().startObject()
+                            .array(SINGLE_VALUED_FIELD_NAME, singleVal.lon(), singleVal.lat())
+                            .startArray(MULTI_VALUED_FIELD_NAME)
+                            .startArray()
+                            .value(multiVal[0].lon())
+                            .value(multiVal[0].lat())
+                            .endArray()
+                            .startArray()
+                            .value(multiVal[1].lon())
+                            .value(multiVal[1].lat())
+                            .endArray()
+                            .endArray()
+                            .field(NUMBER_FIELD_NAME, i)
+                            .field("tag", "tag" + i)
+                            .field(GEO_SHAPE_FIELD_NAME, WKT.toWKT(geoShapesValues[i]))
+                            .endObject()
+                    )
+            );
+            singleCentroid = singleCentroid.reset(
+                singleCentroid.lat() + (singleVal.lat() - singleCentroid.lat()) / (i + 1),
+                singleCentroid.lon() + (singleVal.lon() - singleCentroid.lon()) / (i + 1)
+            );
+            newMVLat = (multiVal[0].lat() + multiVal[1].lat()) / 2d;
+            newMVLon = (multiVal[0].lon() + multiVal[1].lon()) / 2d;
+            multiCentroid = multiCentroid.reset(
+                multiCentroid.lat() + (newMVLat - multiCentroid.lat()) / (i + 1),
+                multiCentroid.lon() + (newMVLon - multiCentroid.lon()) / (i + 1)
+            );
+        }
+
+        assertAcked(
+            prepareCreate(EMPTY_IDX_NAME).setMapping(SINGLE_VALUED_FIELD_NAME, "type=geo_point", GEO_SHAPE_FIELD_NAME, "type=geo_shape")
+        );
+
+        assertAcked(
+            prepareCreate(DATELINE_IDX_NAME).setMapping(
+                SINGLE_VALUED_FIELD_NAME,
+                "type=geo_point",
+                MULTI_VALUED_FIELD_NAME,
+                "type=geo_point",
+                NUMBER_FIELD_NAME,
+                "type=long",
+                "tag",
+                "type=keyword"
+            )
+        );
+
+        GeoPoint[] geoValues = new GeoPoint[5];
+        geoValues[0] = new GeoPoint(38, 178);
+        geoValues[1] = new GeoPoint(12, -179);
+        geoValues[2] = new GeoPoint(-24, 170);
+        geoValues[3] = new GeoPoint(32, -175);
+        geoValues[4] = new GeoPoint(-11, 178);
+
+        for (int i = 0; i < 5; i++) {
+            builders.add(
+                client().prepareIndex(DATELINE_IDX_NAME)
+                    .setSource(
+                        jsonBuilder().startObject()
+                            .array(SINGLE_VALUED_FIELD_NAME, geoValues[i].lon(), geoValues[i].lat())
+                            .field(NUMBER_FIELD_NAME, i)
+                            .field("tag", "tag" + i)
+                            .endObject()
+                    )
+            );
+        }
+        assertAcked(
+            prepareCreate(HIGH_CARD_IDX_NAME).setSettings(Settings.builder().put("number_of_shards", 2))
+                .setMapping(
+                    SINGLE_VALUED_FIELD_NAME,
+                    "type=geo_point",
+                    MULTI_VALUED_FIELD_NAME,
+                    "type=geo_point",
+                    NUMBER_FIELD_NAME,
+                    "type=long,store=true",
+                    "tag",
+                    "type=keyword"
+                )
+        );
+
+        for (int i = 0; i < 2000; i++) {
+            singleVal = singleValues[i % numUniqueGeoPoints];
+            builders.add(
+                client().prepareIndex(HIGH_CARD_IDX_NAME)
+                    .setSource(
+                        jsonBuilder().startObject()
+                            .array(SINGLE_VALUED_FIELD_NAME, singleVal.lon(), singleVal.lat())
+                            .startArray(MULTI_VALUED_FIELD_NAME)
+                            .startArray()
+                            .value(multiValues[i % numUniqueGeoPoints].lon())
+                            .value(multiValues[i % numUniqueGeoPoints].lat())
+                            .endArray()
+                            .startArray()
+                            .value(multiValues[(i + 1) % numUniqueGeoPoints].lon())
+                            .value(multiValues[(i + 1) % numUniqueGeoPoints].lat())
+                            .endArray()
+                            .endArray()
+                            .field(NUMBER_FIELD_NAME, i)
+                            .field("tag", "tag" + i)
+                            .endObject()
+                    )
+            );
+            updateGeohashBucketsCentroid(singleVal);
+        }
+
+        builders.add(
+            client().prepareIndex(IDX_ZERO_NAME)
+                .setSource(jsonBuilder().startObject().array(SINGLE_VALUED_FIELD_NAME, 0.0, 1.0).endObject())
+        );
+        assertAcked(prepareCreate(IDX_ZERO_NAME).setMapping(SINGLE_VALUED_FIELD_NAME, "type=geo_point"));
+
+        indexRandom(true, builders);
+        ensureSearchable();
+
+        // Added to debug a test failure where the terms aggregation seems to be reporting two documents with the same
+        // value for NUMBER_FIELD_NAME. This will check that after random indexing each document only has 1 value for
+        // NUMBER_FIELD_NAME and it is the correct value. Following this initial change its seems that this call was getting
+        // more that 2000 hits (actual value was 2059) so now it will also check to ensure all hits have the correct index and type.
+        SearchResponse response = client().prepareSearch(HIGH_CARD_IDX_NAME)
+            .addStoredField(NUMBER_FIELD_NAME)
+            .addSort(SortBuilders.fieldSort(NUMBER_FIELD_NAME).order(SortOrder.ASC))
+            .setSize(5000)
+            .get();
+        assertSearchResponse(response);
+        long totalHits = response.getHits().getTotalHits().value;
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        response.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        logger.info("Full high_card_idx Response Content:\n{ {} }", builder.toString());
+        for (int i = 0; i < totalHits; i++) {
+            SearchHit searchHit = response.getHits().getAt(i);
+            assertThat("Hit " + i + " with id: " + searchHit.getId(), searchHit.getIndex(), equalTo("high_card_idx"));
+            DocumentField hitField = searchHit.field(NUMBER_FIELD_NAME);
+
+            assertThat("Hit " + i + " has wrong number of values", hitField.getValues().size(), equalTo(1));
+            Long value = hitField.getValue();
+            assertThat("Hit " + i + " has wrong value", value.intValue(), equalTo(i));
+        }
+        assertThat(totalHits, equalTo(2000L));
+    }
+
+    private void updateGeohashBucketsCentroid(final GeoPoint location) {
+        String hash = Geohash.stringEncode(location.lon(), location.lat(), Geohash.PRECISION);
+        for (int precision = Geohash.PRECISION; precision > 0; --precision) {
+            final String h = hash.substring(0, precision);
+            expectedDocCountsForGeoHash.put(h, expectedDocCountsForGeoHash.getOrDefault(h, 0) + 1);
+            expectedCentroidsForGeoHash.put(h, updateHashCentroid(h, location));
+        }
+    }
+
+    private GeoPoint updateHashCentroid(String hash, final GeoPoint location) {
+        GeoPoint centroid = expectedCentroidsForGeoHash.getOrDefault(hash, null);
+        if (centroid == null) {
+            return new GeoPoint(location.lat(), location.lon());
+        }
+        final int docCount = expectedDocCountsForGeoHash.get(hash);
+        final double newLon = centroid.lon() + (location.lon() - centroid.lon()) / docCount;
+        final double newLat = centroid.lat() + (location.lat() - centroid.lat()) / docCount;
+        return centroid.reset(newLat, newLon);
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsITTestCase.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsITTestCase.java
new file mode 100644
index 0000000000000..1c28df6bc4ea2
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsITTestCase.java
@@ -0,0 +1,316 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.util.BigArray;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.bucket.global.Global;
+import org.opensearch.search.aggregations.bucket.terms.Terms;
+import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.hamcrest.MatcherAssert;
+
+import java.util.List;
+
+import static org.opensearch.geo.tests.common.AggregationBuilders.geoBounds;
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.aggregations.AggregationBuilders.global;
+import static org.opensearch.search.aggregations.AggregationBuilders.terms;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.allOf;
+import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.sameInstance;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class GeoBoundsITTestCase extends AbstractGeoAggregatorModulePluginTestCase {
+    private static final String aggName = "geoBounds";
+
+    public GeoBoundsITTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    public void testSingleValuedField() throws Exception {
+        SearchResponse response = client().prepareSearch(IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    public void testSingleValuedField_getProperty() throws Exception {
+        SearchResponse searchResponse = client().prepareSearch(IDX_NAME)
+            .setQuery(matchAllQuery())
+            .addAggregation(global("global").subAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false)))
+            .get();
+
+        assertSearchResponse(searchResponse);
+
+        Global global = searchResponse.getAggregations().get("global");
+        assertThat(global, notNullValue());
+        assertThat(global.getName(), equalTo("global"));
+        assertThat(global.getDocCount(), equalTo((long) numDocs));
+        assertThat(global.getAggregations(), notNullValue());
+        assertThat(global.getAggregations().asMap().size(), equalTo(1));
+
+        GeoBounds geobounds = global.getAggregations().get(aggName);
+        assertThat(geobounds, notNullValue());
+        assertThat(geobounds.getName(), equalTo(aggName));
+        assertThat((GeoBounds) ((InternalAggregation) global).getProperty(aggName), sameInstance(geobounds));
+        GeoPoint topLeft = geobounds.topLeft();
+        GeoPoint bottomRight = geobounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
+        assertThat((double) ((InternalAggregation) global).getProperty(aggName + ".top"), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat((double) ((InternalAggregation) global).getProperty(aggName + ".left"), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(
+            (double) ((InternalAggregation) global).getProperty(aggName + ".bottom"),
+            closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE)
+        );
+        assertThat(
+            (double) ((InternalAggregation) global).getProperty(aggName + ".right"),
+            closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE)
+        );
+    }
+
+    public void testMultiValuedField() throws Exception {
+        SearchResponse response = client().prepareSearch(IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(MULTI_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(multiTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(multiTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(multiBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(multiBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    public void testUnmapped() throws Exception {
+        SearchResponse response = client().prepareSearch(UNMAPPED_IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft, equalTo(null));
+        assertThat(bottomRight, equalTo(null));
+    }
+
+    public void testPartiallyUnmapped() throws Exception {
+        SearchResponse response = client().prepareSearch(IDX_NAME, UNMAPPED_IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    public void testEmptyAggregation() throws Exception {
+        SearchResponse searchResponse = client().prepareSearch(EMPTY_IDX_NAME)
+            .setQuery(matchAllQuery())
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(0L));
+        GeoBounds geoBounds = searchResponse.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft, equalTo(null));
+        assertThat(bottomRight, equalTo(null));
+    }
+
+    public void testSingleValuedFieldNearDateLine() throws Exception {
+        SearchResponse response = client().prepareSearch(DATELINE_IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoPoint geoValuesTopLeft = new GeoPoint(38, -179);
+        GeoPoint geoValuesBottomRight = new GeoPoint(-24, 178);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(geoValuesTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(geoValuesTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(geoValuesBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(geoValuesBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    public void testSingleValuedFieldNearDateLineWrapLongitude() throws Exception {
+
+        GeoPoint geoValuesTopLeft = new GeoPoint(38, 170);
+        GeoPoint geoValuesBottomRight = new GeoPoint(-24, -175);
+        SearchResponse response = client().prepareSearch(DATELINE_IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(true))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(geoValuesTopLeft.lat(), GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(geoValuesTopLeft.lon(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(geoValuesBottomRight.lat(), GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(geoValuesBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    /**
+     * This test forces the {@link GeoBoundsAggregator} to resize the {@link BigArray}s it uses to ensure they are
+     * resized correctly
+     */
+    public void testSingleValuedFieldAsSubAggToHighCardTermsAgg() {
+        SearchResponse response = client().prepareSearch(HIGH_CARD_IDX_NAME)
+            .addAggregation(
+                terms("terms").field(NUMBER_FIELD_NAME)
+                    .subAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        Terms terms = response.getAggregations().get("terms");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getName(), equalTo("terms"));
+        List<? extends Bucket> buckets = terms.getBuckets();
+        assertThat(buckets.size(), equalTo(10));
+        for (int i = 0; i < 10; i++) {
+            Bucket bucket = buckets.get(i);
+            assertThat(bucket, notNullValue());
+            assertThat("InternalBucket " + bucket.getKey() + " has wrong number of documents", bucket.getDocCount(), equalTo(1L));
+            GeoBounds geoBounds = bucket.getAggregations().get(aggName);
+            assertThat(geoBounds, notNullValue());
+            assertThat(geoBounds.getName(), equalTo(aggName));
+            assertThat(geoBounds.topLeft().getLat(), allOf(greaterThanOrEqualTo(-90.0), lessThanOrEqualTo(90.0)));
+            assertThat(geoBounds.topLeft().getLon(), allOf(greaterThanOrEqualTo(-180.0), lessThanOrEqualTo(180.0)));
+            assertThat(geoBounds.bottomRight().getLat(), allOf(greaterThanOrEqualTo(-90.0), lessThanOrEqualTo(90.0)));
+            assertThat(geoBounds.bottomRight().getLon(), allOf(greaterThanOrEqualTo(-180.0), lessThanOrEqualTo(180.0)));
+        }
+    }
+
+    public void testSingleValuedFieldWithZeroLon() throws Exception {
+        SearchResponse response = client().prepareSearch(IDX_ZERO_NAME)
+            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        assertSearchResponse(response);
+
+        GeoBounds geoBounds = response.getAggregations().get(aggName);
+        assertThat(geoBounds, notNullValue());
+        assertThat(geoBounds.getName(), equalTo(aggName));
+        GeoPoint topLeft = geoBounds.topLeft();
+        GeoPoint bottomRight = geoBounds.bottomRight();
+        assertThat(topLeft.lat(), closeTo(1.0, GEOHASH_TOLERANCE));
+        assertThat(topLeft.lon(), closeTo(0.0, GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lat(), closeTo(1.0, GEOHASH_TOLERANCE));
+        assertThat(bottomRight.lon(), closeTo(0.0, GEOHASH_TOLERANCE));
+    }
+
+    public void testGeoShapeValuedField() {
+        final SearchResponse response = client().prepareSearch(IDX_NAME)
+            .addAggregation(geoBounds(aggName).field(GEO_SHAPE_FIELD_NAME).wrapLongitude(false))
+            .get();
+        assertSearchResponse(response);
+        final GeoBounds geoBounds = response.getAggregations().get(aggName);
+        MatcherAssert.assertThat(geoBounds, notNullValue());
+        MatcherAssert.assertThat(geoBounds.getName(), equalTo(aggName));
+        final GeoPoint topLeft = geoBounds.topLeft();
+        final GeoPoint bottomRight = geoBounds.bottomRight();
+        MatcherAssert.assertThat(topLeft.lat(), closeTo(geoShapeTopLeft.lat(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(topLeft.lon(), closeTo(geoShapeTopLeft.lon(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(bottomRight.lat(), closeTo(geoShapeBottomRight.lat(), GEOHASH_TOLERANCE));
+        MatcherAssert.assertThat(bottomRight.lon(), closeTo(geoShapeBottomRight.lon(), GEOHASH_TOLERANCE));
+    }
+
+    public void testEmptyAggregationOnGeoShapes() {
+        final SearchResponse searchResponse = client().prepareSearch(EMPTY_IDX_NAME)
+            .setQuery(matchAllQuery())
+            .addAggregation(geoBounds(aggName).field(GEO_SHAPE_FIELD_NAME).wrapLongitude(false))
+            .get();
+
+        MatcherAssert.assertThat(searchResponse.getHits().getTotalHits().value, equalTo(0L));
+        final GeoBounds geoBounds = searchResponse.getAggregations().get(aggName);
+        MatcherAssert.assertThat(geoBounds, notNullValue());
+        MatcherAssert.assertThat(geoBounds.getName(), equalTo(aggName));
+        final GeoPoint topLeft = geoBounds.topLeft();
+        final GeoPoint bottomRight = geoBounds.bottomRight();
+        MatcherAssert.assertThat(topLeft, equalTo(null));
+        MatcherAssert.assertThat(bottomRight, equalTo(null));
+    }
+}
diff --git a/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoCentroidITTestCase.java b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoCentroidITTestCase.java
new file mode 100644
index 0000000000000..2dc8a91600419
--- /dev/null
+++ b/modules/geo/src/internalClusterTest/java/org/opensearch/geo/search/aggregations/metrics/GeoCentroidITTestCase.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGrid;
+import org.opensearch.geo.tests.common.AggregationBuilders;
+import org.opensearch.search.aggregations.metrics.GeoCentroid;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+
+import static org.opensearch.search.aggregations.AggregationBuilders.geoCentroid;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.notNullValue;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class GeoCentroidITTestCase extends AbstractGeoAggregatorModulePluginTestCase {
+    private static final String aggName = "geoCentroid";
+
+    public GeoCentroidITTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    public void testSingleValueFieldAsSubAggToGeohashGrid() throws Exception {
+        SearchResponse response = client().prepareSearch(HIGH_CARD_IDX_NAME)
+            .addAggregation(
+                AggregationBuilders.geohashGrid("geoGrid")
+                    .field(SINGLE_VALUED_FIELD_NAME)
+                    .subAggregation(geoCentroid(aggName).field(SINGLE_VALUED_FIELD_NAME))
+            )
+            .get();
+        assertSearchResponse(response);
+
+        GeoGrid grid = response.getAggregations().get("geoGrid");
+        assertThat(grid, notNullValue());
+        assertThat(grid.getName(), equalTo("geoGrid"));
+        List<? extends GeoGrid.Bucket> buckets = grid.getBuckets();
+        for (GeoGrid.Bucket cell : buckets) {
+            String geohash = cell.getKeyAsString();
+            GeoPoint expectedCentroid = expectedCentroidsForGeoHash.get(geohash);
+            GeoCentroid centroidAgg = cell.getAggregations().get(aggName);
+            assertThat(
+                "Geohash " + geohash + " has wrong centroid latitude ",
+                expectedCentroid.lat(),
+                closeTo(centroidAgg.centroid().lat(), GEOHASH_TOLERANCE)
+            );
+            assertThat(
+                "Geohash " + geohash + " has wrong centroid longitude",
+                expectedCentroid.lon(),
+                closeTo(centroidAgg.centroid().lon(), GEOHASH_TOLERANCE)
+            );
+        }
+    }
+}
diff --git a/modules/geo/src/main/java/org/opensearch/geo/GeoModulePlugin.java b/modules/geo/src/main/java/org/opensearch/geo/GeoModulePlugin.java
new file mode 100644
index 0000000000000..efee09d01d04e
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/GeoModulePlugin.java
@@ -0,0 +1,106 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo;
+
+import org.opensearch.geo.search.aggregations.bucket.composite.GeoTileGridValuesSourceBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregator;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.InternalGeoHashGrid;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.InternalGeoTileGrid;
+import org.opensearch.geo.search.aggregations.metrics.GeoBounds;
+import org.opensearch.geo.search.aggregations.metrics.GeoBoundsAggregationBuilder;
+import org.opensearch.geo.search.aggregations.metrics.InternalGeoBounds;
+import org.opensearch.index.mapper.GeoShapeFieldMapper;
+import org.opensearch.index.mapper.Mapper;
+import org.opensearch.plugins.MapperPlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregation;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class GeoModulePlugin extends Plugin implements MapperPlugin, SearchPlugin {
+
+    @Override
+    public Map<String, Mapper.TypeParser> getMappers() {
+        return Collections.singletonMap(GeoShapeFieldMapper.CONTENT_TYPE, new GeoShapeFieldMapper.TypeParser());
+    }
+
+    /**
+     * Registering {@link GeoBounds}, {@link InternalGeoHashGrid}, {@link InternalGeoTileGrid} aggregation on GeoPoint and GeoShape
+     * fields.
+     */
+    @Override
+    public List<AggregationSpec> getAggregations() {
+        final AggregationSpec geoBounds = new AggregationSpec(
+            GeoBoundsAggregationBuilder.NAME,
+            GeoBoundsAggregationBuilder::new,
+            GeoBoundsAggregationBuilder.PARSER
+        ).addResultReader(InternalGeoBounds::new).setAggregatorRegistrar(GeoBoundsAggregationBuilder::registerAggregators);
+
+        final AggregationSpec geoHashGrid = new AggregationSpec(
+            GeoHashGridAggregationBuilder.NAME,
+            GeoHashGridAggregationBuilder::new,
+            GeoHashGridAggregationBuilder.PARSER
+        ).addResultReader(InternalGeoHashGrid::new).setAggregatorRegistrar(GeoHashGridAggregationBuilder::registerAggregators);
+
+        final AggregationSpec geoTileGrid = new AggregationSpec(
+            GeoTileGridAggregationBuilder.NAME,
+            GeoTileGridAggregationBuilder::new,
+            GeoTileGridAggregationBuilder.PARSER
+        ).addResultReader(InternalGeoTileGrid::new).setAggregatorRegistrar(GeoTileGridAggregationBuilder::registerAggregators);
+        return List.of(geoBounds, geoHashGrid, geoTileGrid);
+    }
+
+    /**
+     * Registering the {@link GeoTileGridAggregator} in the {@link CompositeAggregation}.
+     *
+     * @return a {@link List} of {@link CompositeAggregationSpec}
+     */
+    @Override
+    public List<CompositeAggregationSpec> getCompositeAggregations() {
+        return Collections.singletonList(
+            new CompositeAggregationSpec(
+                GeoTileGridValuesSourceBuilder::register,
+                GeoTileGridValuesSourceBuilder.class,
+                GeoTileGridValuesSourceBuilder.COMPOSITE_AGGREGATION_SERIALISATION_BYTE_CODE,
+                GeoTileGridValuesSourceBuilder::new,
+                GeoTileGridValuesSourceBuilder::parse,
+                GeoTileGridValuesSourceBuilder.TYPE
+            )
+        );
+    }
+}
diff --git a/modules/geo/src/main/java/org/opensearch/geo/GeoPlugin.java b/modules/geo/src/main/java/org/opensearch/geo/GeoPlugin.java
deleted file mode 100644
index 9b898da33bb12..0000000000000
--- a/modules/geo/src/main/java/org/opensearch/geo/GeoPlugin.java
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.geo;
-
-import org.opensearch.index.mapper.GeoShapeFieldMapper;
-import org.opensearch.index.mapper.Mapper;
-import org.opensearch.plugins.MapperPlugin;
-import org.opensearch.plugins.Plugin;
-
-import java.util.Collections;
-import java.util.Map;
-
-public class GeoPlugin extends Plugin implements MapperPlugin {
-
-    @Override
-    public Map<String, Mapper.TypeParser> getMappers() {
-        return Collections.singletonMap(GeoShapeFieldMapper.CONTENT_TYPE, new GeoShapeFieldMapper.TypeParser());
-    }
-}
diff --git a/modules/geo/src/main/java/org/opensearch/geo/algorithm/PolygonGenerator.java b/modules/geo/src/main/java/org/opensearch/geo/algorithm/PolygonGenerator.java
new file mode 100644
index 0000000000000..da1d97260ec96
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/algorithm/PolygonGenerator.java
@@ -0,0 +1,190 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.algorithm;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.core.common.util.CollectionUtils;
+
+import java.awt.geom.Point2D;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+/**
+ * Helper class to generate a polygon. Keeping this in the src folder so that GeoSpatial plugin can take advantage of
+ * this helper to create the Polygons, rather than hardcoding the values.
+ */
+public class PolygonGenerator {
+
+    private static final Logger LOG = LogManager.getLogger(PolygonGenerator.class);
+
+    /**
+     * A helper function to create the Polygons for testing. The returned list of double array where first element
+     * contains all the X points and second contains all the Y points.
+     *
+     * @param xPool a {@link java.util.List} of {@link Double}
+     * @param yPool a {@link java.util.List} of {@link Double}
+     * @return a {@link List} of double array.
+     */
+    public static List<double[]> generatePolygon(final List<Double> xPool, final List<Double> yPool, final Random random) {
+        if (CollectionUtils.isEmpty(xPool) || CollectionUtils.isEmpty(yPool)) {
+            LOG.debug("One of the X or Y list is empty or null. X.size : {} Y.size : {}", xPool, yPool);
+            return Collections.emptyList();
+        }
+        final List<Point2D.Double> generatedPolygonPointsList = ValtrAlgorithm.generateRandomConvexPolygon(xPool, yPool, random);
+        final double[] x = new double[generatedPolygonPointsList.size()];
+        final double[] y = new double[generatedPolygonPointsList.size()];
+        IntStream.range(0, generatedPolygonPointsList.size()).forEach(iterator -> {
+            x[iterator] = generatedPolygonPointsList.get(iterator).getX();
+            y[iterator] = generatedPolygonPointsList.get(iterator).getY();
+        });
+        final List<double[]> pointsList = new ArrayList<>();
+        pointsList.add(x);
+        pointsList.add(y);
+        return pointsList;
+    }
+
+    /*
+     * MIT License
+     *
+     * Copyright (c) 2017 Sander Verdonschot
+     *
+     * Permission is hereby granted, free of charge, to any person obtaining a copy
+     * of this software and associated documentation files (the "Software"), to deal
+     * in the Software without restriction, including without limitation the rights
+     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+     * copies of the Software, and to permit persons to whom the Software is
+     * furnished to do so, subject to the following conditions:
+     *
+     * The above copyright notice and this permission notice shall be included in all
+     * copies or substantial portions of the Software.
+     *
+     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+     * SOFTWARE.
+     */
+    /**
+     * Provides a helper function to create a Polygon with a list of points. This source code is used to create the
+     * polygons in the test cases.
+     * <a href="https://cglab.ca/~sander/misc/ConvexGeneration/ValtrAlgorithm.java">Reference Link</a>
+     * <a href="https://observablehq.com/@tarte0/generate-random-simple-polygon">Visual Link</a>
+     */
+    private static class ValtrAlgorithm {
+        /**
+         * Generates a convex polygon using the points provided as a {@link List} of {@link Double} for both X and Y axis.
+         *
+         * @param xPool a {@link List} of {@link Double}
+         * @param yPool a {@link List} of {@link Double}
+         * @return a {@link List} of {@link Point2D.Double}
+         */
+        private static List<Point2D.Double> generateRandomConvexPolygon(
+            final List<Double> xPool,
+            final List<Double> yPool,
+            final Random random
+        ) {
+            final int n = xPool.size();
+            // Sort them
+            Collections.sort(xPool);
+            Collections.sort(yPool);
+
+            // Isolate the extreme points
+            final Double minX = xPool.get(0);
+            final Double maxX = xPool.get(n - 1);
+            final Double minY = yPool.get(0);
+            final Double maxY = yPool.get(n - 1);
+
+            // Divide the interior points into two chains & Extract the vector components
+            java.util.List<Double> xVec = new ArrayList<>(n);
+            java.util.List<Double> yVec = new ArrayList<>(n);
+
+            double lastTop = minX, lastBot = minX;
+
+            for (int i = 1; i < n - 1; i++) {
+                double x = xPool.get(i);
+
+                if (random.nextBoolean()) {
+                    xVec.add(x - lastTop);
+                    lastTop = x;
+                } else {
+                    xVec.add(lastBot - x);
+                    lastBot = x;
+                }
+            }
+
+            xVec.add(maxX - lastTop);
+            xVec.add(lastBot - maxX);
+
+            double lastLeft = minY, lastRight = minY;
+
+            for (int i = 1; i < n - 1; i++) {
+                double y = yPool.get(i);
+
+                if (random.nextBoolean()) {
+                    yVec.add(y - lastLeft);
+                    lastLeft = y;
+                } else {
+                    yVec.add(lastRight - y);
+                    lastRight = y;
+                }
+            }
+
+            yVec.add(maxY - lastLeft);
+            yVec.add(lastRight - maxY);
+
+            // Randomly pair up the X- and Y-components
+            Collections.shuffle(yVec, random);
+
+            // Combine the paired up components into vectors
+            List<Point2D.Double> vec = new ArrayList<>(n);
+
+            for (int i = 0; i < n; i++) {
+                vec.add(new Point2D.Double(xVec.get(i), yVec.get(i)));
+            }
+
+            // Sort the vectors by angle
+            Collections.sort(vec, Comparator.comparingDouble(v -> Math.atan2(v.getY(), v.getX())));
+
+            // Lay them end-to-end
+            double x = 0, y = 0;
+            double minPolygonX = 0;
+            double minPolygonY = 0;
+            List<Point2D.Double> points = new ArrayList<>(n);
+
+            for (int i = 0; i < n; i++) {
+                points.add(new Point2D.Double(x, y));
+
+                x += vec.get(i).getX();
+                y += vec.get(i).getY();
+
+                minPolygonX = Math.min(minPolygonX, x);
+                minPolygonY = Math.min(minPolygonY, y);
+            }
+
+            // Move the polygon to the original min and max coordinates
+            double xShift = minX - minPolygonX;
+            double yShift = minY - minPolygonY;
+
+            for (int i = 0; i < n; i++) {
+                Point2D.Double p = points.get(i);
+                points.set(i, new Point2D.Double(p.x + xShift, p.y + yShift));
+            }
+
+            return points;
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java
similarity index 82%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java
index 5d47a44a26222..c6fcdf7c81ea8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilder.java
@@ -30,25 +30,28 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.composite;
+package org.opensearch.geo.search.aggregations.bucket.composite;
 
 import org.apache.lucene.index.IndexReader;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.cells.CellIdSource;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
-import org.opensearch.search.aggregations.bucket.geogrid.CellIdSource;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceBuilder;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceConfig;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceParserHelper;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
 import org.opensearch.search.aggregations.support.ValuesSource;
@@ -62,7 +65,17 @@
 import java.util.function.LongConsumer;
 import java.util.function.LongUnaryOperator;
 
+/**
+ * Builds values source for geotile_grid agg
+ *
+ * @opensearch.internal
+ */
 public class GeoTileGridValuesSourceBuilder extends CompositeValuesSourceBuilder<GeoTileGridValuesSourceBuilder> {
+    /**
+     * Supplier for a composite geotile
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface GeoTileCompositeSuppier {
         CompositeValuesSourceConfig apply(
@@ -78,13 +91,19 @@ CompositeValuesSourceConfig apply(
         );
     }
 
-    static final String TYPE = "geotile_grid";
+    public static final String TYPE = "geotile_grid";
+    /*
+        use the TYPE parameter instead of Byte code. The byte code is added for backward compatibility and will be
+        removed in the next version.
+     */
+    @Deprecated
+    public static final Byte COMPOSITE_AGGREGATION_SERIALISATION_BYTE_CODE = 3;
     static final ValuesSourceRegistry.RegistryKey<GeoTileCompositeSuppier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey(
         TYPE,
         GeoTileCompositeSuppier.class
     );
 
-    private static final ObjectParser<GeoTileGridValuesSourceBuilder, Void> PARSER;
+    static final ObjectParser<GeoTileGridValuesSourceBuilder, Void> PARSER;
     static {
         PARSER = new ObjectParser<>(GeoTileGridValuesSourceBuilder.TYPE);
         PARSER.declareInt(GeoTileGridValuesSourceBuilder::precision, new ParseField("precision"));
@@ -96,11 +115,11 @@ CompositeValuesSourceConfig apply(
         CompositeValuesSourceParserHelper.declareValuesSourceFields(PARSER);
     }
 
-    static GeoTileGridValuesSourceBuilder parse(String name, XContentParser parser) throws IOException {
+    public static GeoTileGridValuesSourceBuilder parse(String name, XContentParser parser) throws IOException {
         return PARSER.parse(parser, new GeoTileGridValuesSourceBuilder(name), null);
     }
 
-    static void register(ValuesSourceRegistry.Builder builder) {
+    public static void register(ValuesSourceRegistry.Builder builder) {
 
         builder.register(
             REGISTRY_KEY,
@@ -153,7 +172,7 @@ static void register(ValuesSourceRegistry.Builder builder) {
         super(name);
     }
 
-    GeoTileGridValuesSourceBuilder(StreamInput in) throws IOException {
+    public GeoTileGridValuesSourceBuilder(StreamInput in) throws IOException {
         super(in);
         this.precision = in.readInt();
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
@@ -193,7 +212,7 @@ protected void doXContentBody(XContentBuilder builder, Params params) throws IOE
     }
 
     @Override
-    String type() {
+    protected String type() {
         return TYPE;
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileValuesSource.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileValuesSource.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileValuesSource.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileValuesSource.java
index 2daddc9647f44..9149b8939b739 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GeoTileValuesSource.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileValuesSource.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.composite;
+package org.opensearch.geo.search.aggregations.bucket.composite;
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SortedNumericDocValues;
@@ -38,7 +38,9 @@
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.search.DocValueFormat;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.composite.LongValuesSource;
+import org.opensearch.search.aggregations.bucket.composite.SingleDimensionValuesSource;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 
 import java.io.IOException;
@@ -49,6 +51,8 @@
  *
  * Since geotile values can be represented as long values, this class is almost the same as {@link LongValuesSource}
  * The main differences is {@link GeoTileValuesSource#setAfter(Comparable)} as it needs to accept geotile string values i.e. "zoom/x/y".
+ *
+ * @opensearch.internal
  */
 class GeoTileValuesSource extends LongValuesSource {
     GeoTileValuesSource(
@@ -66,7 +70,7 @@ class GeoTileValuesSource extends LongValuesSource {
     }
 
     @Override
-    void setAfter(Comparable value) {
+    protected void setAfter(Comparable value) {
         if (missingBucket && value == null) {
             afterValue = null;
         } else if (value instanceof Number) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BucketPriorityQueue.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/BucketPriorityQueue.java
similarity index 91%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BucketPriorityQueue.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/BucketPriorityQueue.java
index 3a8245a52adfc..70d0552b3e80b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BucketPriorityQueue.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/BucketPriorityQueue.java
@@ -29,10 +29,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.apache.lucene.util.PriorityQueue;
 
+/**
+ * Internal priority queue for computing geogrid relations
+ *
+ * @opensearch.internal
+ */
 class BucketPriorityQueue<B extends InternalGeoGridBucket> extends PriorityQueue<B> {
 
     BucketPriorityQueue(int size) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGrid.java
similarity index 95%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGrid.java
index 7521f9f58bd96..4ae888640efc8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGrid.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 
@@ -38,6 +38,8 @@
 /**
  * A geo-grid aggregation. Defines multiple buckets, each representing a cell in a geo-grid of a specific
  * precision.
+ *
+ * @opensearch.internal
  */
 public interface GeoGrid extends MultiBucketsAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java
similarity index 93%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java
index 5ec17c951d183..11be1bd70fa30 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregationBuilder.java
@@ -30,18 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
 import org.opensearch.search.aggregations.AggregatorFactory;
@@ -57,6 +57,11 @@
 import java.util.Objects;
 import java.util.function.Function;
 
+/**
+ * Base Aggregation Builder for geogrid aggs
+ *
+ * @opensearch.internal
+ */
 public abstract class GeoGridAggregationBuilder extends ValuesSourceAggregationBuilder<GeoGridAggregationBuilder> {
     /* recognized field names in JSON */
     static final ParseField FIELD_PRECISION = new ParseField("precision");
@@ -68,6 +73,11 @@ public abstract class GeoGridAggregationBuilder extends ValuesSourceAggregationB
     protected int shardSize;
     private GeoBoundingBox geoBoundingBox = new GeoBoundingBox(new GeoPoint(Double.NaN, Double.NaN), new GeoPoint(Double.NaN, Double.NaN));
 
+    /**
+     * A precision parser
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     protected interface PrecisionParser {
         int parse(XContentParser parser) throws IOException;
@@ -83,14 +93,14 @@ public static <T extends GeoGridAggregationBuilder> ObjectParser<T, String> crea
         parser.declareField(
             (p, builder, context) -> builder.precision(precisionParser.parse(p)),
             FIELD_PRECISION,
-            org.opensearch.common.xcontent.ObjectParser.ValueType.INT
+            ObjectParser.ValueType.INT
         );
         parser.declareInt(GeoGridAggregationBuilder::size, FIELD_SIZE);
         parser.declareInt(GeoGridAggregationBuilder::shardSize, FIELD_SHARD_SIZE);
         parser.declareField(
             (p, builder, context) -> { builder.setGeoBoundingBox(GeoBoundingBox.parseBoundingBox(p)); },
             GeoBoundingBox.BOUNDS_FIELD,
-            org.opensearch.common.xcontent.ObjectParser.ValueType.OBJECT
+            ObjectParser.ValueType.OBJECT
         );
         return parser;
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregator.java
similarity index 95%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregator.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregator.java
index 7eb05adf78e45..01f9f22be9e68 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregator.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregator.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SortedNumericDocValues;
@@ -54,6 +54,8 @@
 
 /**
  * Aggregates data expressed as longs (for efficiency's sake) but formats results as aggregation-specific strings.
+ *
+ * @opensearch.internal
  */
 public abstract class GeoGridAggregator<T extends InternalGeoGrid> extends BucketsAggregator {
 
@@ -62,7 +64,7 @@ public abstract class GeoGridAggregator<T extends InternalGeoGrid> extends Bucke
     protected final ValuesSource.Numeric valuesSource;
     protected final LongKeyedBucketOrds bucketOrds;
 
-    GeoGridAggregator(
+    protected GeoGridAggregator(
         String name,
         AggregatorFactories factories,
         ValuesSource.Numeric valuesSource,
@@ -116,14 +118,14 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
         };
     }
 
-    abstract T buildAggregation(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata);
+    protected abstract T buildAggregation(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata);
 
     /**
      * This method is used to return a re-usable instance of the bucket when building
      * the aggregation.
      * @return a new {@link InternalGeoGridBucket} implementation with empty parameters
      */
-    abstract InternalGeoGridBucket newEmptyBucket();
+    protected abstract InternalGeoGridBucket newEmptyBucket();
 
     @Override
     public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoGridAggregatorSupplier.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorSupplier.java
similarity index 92%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/GeoGridAggregatorSupplier.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorSupplier.java
index 3c29c3558eb35..0ef1957f88ef6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoGridAggregatorSupplier.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorSupplier.java
@@ -30,19 +30,23 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGridAggregator;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base Aggregator supplier interface for geo grid aggs
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface GeoGridAggregatorSupplier {
     GeoGridAggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java
similarity index 94%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java
index a1ae76eb034d0..57f1eceabd3da 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregationBuilder.java
@@ -30,17 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.AggregatorFactory;
-import org.opensearch.search.aggregations.metrics.GeoGridAggregatorSupplier;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.opensearch.search.aggregations.support.ValuesSourceConfig;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
@@ -48,6 +47,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for geohash_grid
+ *
+ * @opensearch.internal
+ */
 public class GeoHashGridAggregationBuilder extends GeoGridAggregationBuilder {
     public static final String NAME = "geohash_grid";
     public static final int DEFAULT_PRECISION = 5;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java
index 74c8170458734..16bd8b5a42f5f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -44,6 +44,8 @@
 
 /**
  * Aggregates data expressed as GeoHash longs (for efficiency's sake) but formats results as Geohash strings.
+ *
+ * @opensearch.internal
  */
 public class GeoHashGridAggregator extends GeoGridAggregator<InternalGeoHashGrid> {
 
@@ -62,7 +64,12 @@ public GeoHashGridAggregator(
     }
 
     @Override
-    InternalGeoHashGrid buildAggregation(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata) {
+    protected InternalGeoHashGrid buildAggregation(
+        String name,
+        int requiredSize,
+        List<InternalGeoGridBucket> buckets,
+        Map<String, Object> metadata
+    ) {
         return new InternalGeoHashGrid(name, requiredSize, buckets, metadata);
     }
 
@@ -71,7 +78,8 @@ public InternalGeoHashGrid buildEmptyAggregation() {
         return new InternalGeoHashGrid(name, requiredSize, Collections.emptyList(), metadata());
     }
 
-    InternalGeoGridBucket newEmptyBucket() {
+    @Override
+    protected InternalGeoGridBucket newEmptyBucket() {
         return new InternalGeoHashGridBucket(0, 0, null);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java
similarity index 76%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java
index a52ee2018fdfe..b95b47a630916 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorFactory.java
@@ -30,9 +30,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.cells.CellIdSource;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.cells.GeoShapeCellIdSource;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.util.GeoShapeHashUtil;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.Aggregator;
@@ -53,6 +56,11 @@
 
 import static java.util.Collections.emptyList;
 
+/**
+ * Aggregation Factory for geohash_grid agg
+ *
+ * @opensearch.internal
+ */
 public class GeoHashGridAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final int precision;
@@ -115,6 +123,7 @@ protected Aggregator doCreateInternal(
     }
 
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
+        // register GeoPoint Aggregation
         builder.register(
             GeoHashGridAggregationBuilder.REGISTRY_KEY,
             CoreValuesSourceType.GEOPOINT,
@@ -150,5 +159,46 @@ static void registerAggregators(ValuesSourceRegistry.Builder builder) {
             },
             true
         );
+        // register GeoShape Aggregation
+        builder.register(
+            GeoHashGridAggregationBuilder.REGISTRY_KEY,
+            CoreValuesSourceType.GEO_SHAPE,
+            (
+                name,
+                factories,
+                valuesSource,
+                precision,
+                geoBoundingBox,
+                requiredSize,
+                shardSize,
+                aggregationContext,
+                parent,
+                cardinality,
+                metadata) -> {
+                final GeoShapeCellIdSource cellIdSource = new GeoShapeCellIdSource(
+                    (ValuesSource.GeoShape) valuesSource,
+                    precision,
+                    geoBoundingBox,
+                    GeoShapeHashUtil::encodeShape
+                );
+                return new GeoHashGridAggregator(
+                    name,
+                    factories,
+                    cellIdSource,
+                    requiredSize,
+                    shardSize,
+                    aggregationContext,
+                    parent,
+                    cardinality,
+                    metadata
+                );
+            },
+            true
+        );
+    }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java
similarity index 93%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java
index 6828077cd4778..3454e5491617d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregationBuilder.java
@@ -30,16 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoBoundingBox;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.AggregatorFactory;
-import org.opensearch.search.aggregations.metrics.GeoGridAggregatorSupplier;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.opensearch.search.aggregations.support.ValuesSourceConfig;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
@@ -47,6 +47,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for geotile_grid agg
+ *
+ * @opensearch.internal
+ */
 public class GeoTileGridAggregationBuilder extends GeoGridAggregationBuilder {
     public static final String NAME = "geotile_grid";
     public static final int DEFAULT_PRECISION = 7;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java
index 390f613686272..f4492d561aa7f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregator.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -45,6 +45,8 @@
 
 /**
  * Aggregates data expressed as geotile longs (for efficiency's sake) but formats results as geotile strings.
+ *
+ * @opensearch.internal
  */
 public class GeoTileGridAggregator extends GeoGridAggregator<InternalGeoTileGrid> {
 
@@ -63,7 +65,12 @@ public GeoTileGridAggregator(
     }
 
     @Override
-    InternalGeoTileGrid buildAggregation(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata) {
+    protected InternalGeoTileGrid buildAggregation(
+        String name,
+        int requiredSize,
+        List<InternalGeoGridBucket> buckets,
+        Map<String, Object> metadata
+    ) {
         return new InternalGeoTileGrid(name, requiredSize, buckets, metadata);
     }
 
@@ -72,7 +79,8 @@ public InternalGeoTileGrid buildEmptyAggregation() {
         return new InternalGeoTileGrid(name, requiredSize, Collections.emptyList(), metadata());
     }
 
-    InternalGeoGridBucket newEmptyBucket() {
+    @Override
+    protected InternalGeoGridBucket newEmptyBucket() {
         return new InternalGeoTileGridBucket(0, 0, null);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java
similarity index 76%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java
index 616451474abc4..7253f45d2db10 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorFactory.java
@@ -30,9 +30,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.cells.CellIdSource;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.cells.GeoShapeCellIdSource;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -40,6 +42,7 @@
 import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.NonCollectingAggregator;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -51,6 +54,11 @@
 import java.util.Collections;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for geo_tile grid agg
+ *
+ * @opensearch.internal
+ */
 public class GeoTileGridAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final int precision;
@@ -148,5 +156,47 @@ static void registerAggregators(ValuesSourceRegistry.Builder builder) {
             },
             true
         );
+
+        // registers Aggregation on GeoShape
+        builder.register(
+            GeoTileGridAggregationBuilder.REGISTRY_KEY,
+            CoreValuesSourceType.GEO_SHAPE,
+            (
+                name,
+                factories,
+                valuesSource,
+                precision,
+                geoBoundingBox,
+                requiredSize,
+                shardSize,
+                aggregationContext,
+                parent,
+                cardinality,
+                metadata) -> {
+                GeoShapeCellIdSource cellIdSource = new GeoShapeCellIdSource(
+                    (ValuesSource.GeoShape) valuesSource,
+                    precision,
+                    geoBoundingBox,
+                    GeoTileUtils::encodeShape
+                );
+                return new GeoTileGridAggregator(
+                    name,
+                    factories,
+                    cellIdSource,
+                    requiredSize,
+                    shardSize,
+                    aggregationContext,
+                    parent,
+                    cardinality,
+                    metadata
+                );
+            },
+            true
+        );
+    }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGrid.java
similarity index 89%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGrid.java
index e7fed7c735b25..00b7926641659 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGrid.java
@@ -29,13 +29,12 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.LongObjectPagedHashMap;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
@@ -53,6 +52,8 @@
  * Represents a grid of cells where each cell's location is determined by a specific geo hashing algorithm.
  * All geo-grid hash-encoding in a grid are of the same precision and held internally as a single long
  * for efficiency's sake.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalGeoGrid<B extends InternalGeoGridBucket> extends InternalMultiBucketAggregation<
     InternalGeoGrid,
@@ -61,13 +62,13 @@ public abstract class InternalGeoGrid<B extends InternalGeoGridBucket> extends I
     protected final int requiredSize;
     protected final List<InternalGeoGridBucket> buckets;
 
-    InternalGeoGrid(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata) {
+    protected InternalGeoGrid(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata) {
         super(name, metadata);
         this.requiredSize = requiredSize;
         this.buckets = buckets;
     }
 
-    abstract Writeable.Reader<B> getBucketReader();
+    protected abstract Reader<B> getBucketReader();
 
     /**
      * Read from a stream.
@@ -84,7 +85,12 @@ protected void doWriteTo(StreamOutput out) throws IOException {
         out.writeList(buckets);
     }
 
-    abstract InternalGeoGrid create(String name, int requiredSize, List<InternalGeoGridBucket> buckets, Map<String, Object> metadata);
+    protected abstract InternalGeoGrid create(
+        String name,
+        int requiredSize,
+        List<InternalGeoGridBucket> buckets,
+        Map<String, Object> metadata
+    );
 
     @Override
     public List<InternalGeoGridBucket> getBuckets() {
@@ -138,7 +144,7 @@ protected InternalGeoGridBucket reduceBucket(List<InternalGeoGridBucket> buckets
         return createBucket(buckets.get(0).hashAsLong, docCount, aggs);
     }
 
-    abstract B createBucket(long hashAsLong, long docCount, InternalAggregations aggregations);
+    protected abstract B createBucket(long hashAsLong, long docCount, InternalAggregations aggregations);
 
     @Override
     public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java
similarity index 91%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java
index 0ddfed84fbe99..148e2d14bb643 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoGridBucket.java
@@ -29,11 +29,11 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Base implementation of geogrid aggs
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalGeoGridBucket<B extends InternalGeoGridBucket> extends InternalMultiBucketAggregation.InternalBucket
     implements
         GeoGrid.Bucket,
@@ -75,7 +80,7 @@ public void writeTo(StreamOutput out) throws IOException {
         aggregations.writeTo(out);
     }
 
-    long hashAsLong() {
+    public long hashAsLong() {
         return hashAsLong;
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java
similarity index 85%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java
index bae4f99d3bb5b..5f8f7aabf8e99 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java
@@ -29,9 +29,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 
 import java.io.IOException;
@@ -42,6 +42,8 @@
  * Represents a grid of cells where each cell's location is determined by a geohash.
  * All geohashes in a grid are of the same precision and held internally as a single long
  * for efficiency's sake.
+ *
+ * @opensearch.internal
  */
 public class InternalGeoHashGrid extends InternalGeoGrid<InternalGeoHashGridBucket> {
 
@@ -64,17 +66,17 @@ public InternalGeoGridBucket createBucket(InternalAggregations aggregations, Int
     }
 
     @Override
-    InternalGeoGrid create(String name, int requiredSize, List buckets, Map metadata) {
+    protected InternalGeoGrid create(String name, int requiredSize, List buckets, Map metadata) {
         return new InternalGeoHashGrid(name, requiredSize, buckets, metadata);
     }
 
     @Override
-    InternalGeoHashGridBucket createBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
+    protected InternalGeoHashGridBucket createBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
         return new InternalGeoHashGridBucket(hashAsLong, docCount, aggregations);
     }
 
     @Override
-    Reader getBucketReader() {
+    protected Reader<InternalGeoHashGridBucket> getBucketReader() {
         return InternalGeoHashGridBucket::new;
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java
similarity index 90%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java
index a5bead1f17280..962053ec1cf7c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoHashGridBucket.java
@@ -29,15 +29,20 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.search.aggregations.InternalAggregations;
 
 import java.io.IOException;
 
+/**
+ * Implementation of geohash grid bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalGeoHashGridBucket extends InternalGeoGridBucket<InternalGeoHashGridBucket> {
     InternalGeoHashGridBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
         super(hashAsLong, docCount, aggregations);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java
similarity index 85%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java
index d7ff2c0a2cd33..1ff6cc6547575 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGrid.java
@@ -29,9 +29,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 
 import java.io.IOException;
@@ -42,6 +42,8 @@
  * Represents a grid of cells where each cell's location is determined by a geohash.
  * All geohashes in a grid are of the same precision and held internally as a single long
  * for efficiency's sake.
+ *
+ * @opensearch.internal
  */
 public class InternalGeoTileGrid extends InternalGeoGrid<InternalGeoTileGridBucket> {
 
@@ -64,17 +66,17 @@ public InternalGeoGridBucket createBucket(InternalAggregations aggregations, Int
     }
 
     @Override
-    InternalGeoGrid create(String name, int requiredSize, List buckets, Map metadata) {
+    protected InternalGeoGrid create(String name, int requiredSize, List buckets, Map metadata) {
         return new InternalGeoTileGrid(name, requiredSize, buckets, metadata);
     }
 
     @Override
-    InternalGeoTileGridBucket createBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
+    protected InternalGeoTileGridBucket createBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
         return new InternalGeoTileGridBucket(hashAsLong, docCount, aggregations);
     }
 
     @Override
-    Reader getBucketReader() {
+    protected Reader<InternalGeoTileGridBucket> getBucketReader() {
         return InternalGeoTileGridBucket::new;
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java
index b08ef55a71f5b..a448cb162aacb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/InternalGeoTileGridBucket.java
@@ -30,14 +30,20 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 
 import java.io.IOException;
 
+/**
+ * Implementation of geotile grid bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalGeoTileGridBucket extends InternalGeoGridBucket<InternalGeoTileGridBucket> {
     InternalGeoTileGridBucket(long hashAsLong, long docCount, InternalAggregations aggregations) {
         super(hashAsLong, docCount, aggregations);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGrid.java
similarity index 88%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGrid.java
index 59681a52b1c01..89bc917a0b023 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGrid.java
@@ -30,17 +30,22 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.function.Supplier;
 
+/**
+ * A geo grid result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedGeoGrid extends ParsedMultiBucketAggregation<ParsedGeoGridBucket> implements GeoGrid {
 
     @Override
@@ -58,7 +63,7 @@ public static ObjectParser<ParsedGeoGrid, Void> createParser(
         return parser;
     }
 
-    protected void setName(String name) {
+    public void setName(String name) {
         super.setName(name);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java
similarity index 88%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java
index f09eb46fd8a48..47b212dca5744 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoGridBucket.java
@@ -29,14 +29,19 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A single geo grid bucket result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedGeoGridBucket extends ParsedMultiBucketAggregation.ParsedBucket implements GeoGrid.Bucket {
 
     protected String hashAsString;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java
index 189bfb4b58c92..cc5ed1c0bff16 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGrid.java
@@ -30,13 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A geohash grid result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoHashGrid extends ParsedGeoGrid {
 
     private static final ObjectParser<ParsedGeoGrid, Void> PARSER = createParser(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java
similarity index 88%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java
index 3ed6cfe41ba77..6932cc74d3c1f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoHashGridBucket.java
@@ -29,13 +29,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A single geohash grid bucket result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoHashGridBucket extends ParsedGeoGridBucket {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java
similarity index 87%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java
index 011fe2c9102c7..c136ad3fac17d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGrid.java
@@ -30,13 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A geotile grid result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoTileGrid extends ParsedGeoGrid {
 
     private static final ObjectParser<ParsedGeoGrid, Void> PARSER = createParser(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java
similarity index 85%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java
index 5b2bdd163d8f2..3f43ef6cdd5a8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/ParsedGeoTileGridBucket.java
@@ -30,13 +30,19 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 
 import java.io.IOException;
 
+/**
+ * A single geotile grid bucket result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoTileGridBucket extends ParsedGeoGridBucket {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BoundedCellValues.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/BoundedCellValues.java
similarity index 95%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BoundedCellValues.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/BoundedCellValues.java
index cc4f5835cabf1..588c8bc59c2e0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/BoundedCellValues.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/BoundedCellValues.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
 
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
@@ -39,6 +39,8 @@
  * according to whether they are within the specified {@link GeoBoundingBox}.
  *
  * The specified bounding box is assumed to be bounded.
+ *
+ * @opensearch.internal
  */
 class BoundedCellValues extends CellValues {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellIdSource.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellIdSource.java
similarity index 93%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellIdSource.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellIdSource.java
index c9ea7696cd7f5..42c4722e065af 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellIdSource.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellIdSource.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SortedNumericDocValues;
@@ -42,6 +42,8 @@
 /**
  * Wrapper class to help convert {@link MultiGeoPointValues}
  * to numeric long values for bucketing.
+ *
+ * @opensearch.internal
  */
 public class CellIdSource extends ValuesSource.Numeric {
     private final ValuesSource.GeoPoint valuesSource;
@@ -66,6 +68,11 @@ public boolean isFloatingPoint() {
         return false;
     }
 
+    @Override
+    public boolean isBigInteger() {
+        return false;
+    }
+
     @Override
     public SortedNumericDocValues longValues(LeafReaderContext ctx) {
         if (geoBoundingBox.isUnbounded()) {
@@ -87,6 +94,8 @@ public SortedBinaryDocValues bytesValues(LeafReaderContext ctx) {
     /**
      * The encoder to use to convert a geopoint's (lon, lat, precision) into
      * a long-encoded bucket key for aggregating.
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface GeoPointLongEncoder {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellValues.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellValues.java
similarity index 96%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellValues.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellValues.java
index 2e8344f203a39..0b69040ec977a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/CellValues.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/CellValues.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
 
 import org.opensearch.index.fielddata.AbstractSortingNumericDocValues;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
@@ -40,6 +40,8 @@
  * Class representing the long-encoded grid-cells belonging to
  * the geo-doc-values. Class must encode the values and then
  * sort them in order to account for the cells correctly.
+ *
+ * @opensearch.internal
  */
 abstract class CellValues extends AbstractSortingNumericDocValues {
     private MultiGeoPointValues geoValues;
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellIdSource.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellIdSource.java
new file mode 100644
index 0000000000000..0ea4d96c450ec
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellIdSource.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.index.fielddata.GeoShapeValue;
+import org.opensearch.index.fielddata.SortedBinaryDocValues;
+import org.opensearch.index.fielddata.SortedNumericDoubleValues;
+import org.opensearch.search.aggregations.support.ValuesSource;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * ValueSource class which converts the {@link GeoShapeValue} to numeric long values for bucketing. This class uses the
+ * {@link GeoShapeCellIdSource.GeoShapeLongEncoder} to encode the geo_shape to {@link Long} values which can be iterated
+ * to do the bucket aggregation.
+ *
+ * @opensearch.internal
+ */
+public class GeoShapeCellIdSource extends ValuesSource.Numeric {
+
+    private final ValuesSource.GeoShape geoShape;
+    private final int precision;
+    private final GeoBoundingBox geoBoundingBox;
+    private final GeoShapeCellIdSource.GeoShapeLongEncoder encoder;
+
+    public GeoShapeCellIdSource(
+        final ValuesSource.GeoShape geoShape,
+        final int precision,
+        final GeoBoundingBox geoBoundingBox,
+        final GeoShapeCellIdSource.GeoShapeLongEncoder encoder
+    ) {
+        this.geoShape = geoShape;
+        this.geoBoundingBox = geoBoundingBox;
+        this.precision = precision;
+        this.encoder = encoder;
+    }
+
+    /**
+     * Get the current {@link SortedBinaryDocValues}.
+     *
+     * @param context {@link LeafReaderContext}
+     */
+    @Override
+    public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOException {
+        throw new UnsupportedOperationException("The bytesValues operation is not supported on GeoShapeCellIdSource");
+    }
+
+    /**
+     * Whether the underlying data is floating-point or not.
+     */
+    @Override
+    public boolean isFloatingPoint() {
+        return false;
+    }
+
+    /**
+     * Whether the underlying data is big integer or not.
+     */
+    @Override
+    public boolean isBigInteger() {
+        return false;
+    }
+
+    /**
+     * Get the current {@link SortedNumericDocValues}.
+     *
+     * @param context {@link LeafReaderContext}
+     */
+    @Override
+    public SortedNumericDocValues longValues(final LeafReaderContext context) {
+        if (geoBoundingBox.isUnbounded()) {
+            return new GeoShapeCellValues.UnboundedCellValues(geoShape.getGeoShapeValues(context), precision, encoder);
+        }
+        return new GeoShapeCellValues.BoundedCellValues(geoShape.getGeoShapeValues(context), precision, encoder, geoBoundingBox);
+    }
+
+    /**
+     * Get the current {@link SortedNumericDoubleValues}.
+     *
+     * @param context {@link LeafReaderContext}
+     */
+    @Override
+    public SortedNumericDoubleValues doubleValues(LeafReaderContext context) {
+        throw new UnsupportedOperationException("The doubleValues operation is not supported on GeoShapeCellIdSource");
+    }
+
+    /**
+     * Encoder to encode the GeoShapes to the specific long values for the aggregation.
+     *
+     * @opensearch.internal
+     */
+    @FunctionalInterface
+    public interface GeoShapeLongEncoder {
+        List<Long> encode(final GeoShapeDocValue geoShapeDocValue, final int precision);
+    }
+}
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellValues.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellValues.java
new file mode 100644
index 0000000000000..123a98fab3713
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/GeoShapeCellValues.java
@@ -0,0 +1,127 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
+
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.index.fielddata.AbstractSortingNumericDocValues;
+import org.opensearch.index.fielddata.GeoShapeValue;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * Class representing the long-encoded grid-cells belonging to the geoshape-doc-values. Class must encode the values
+ * as long and then sort them in order to account for the cells correctly.
+ *
+ * @opensearch.internal
+ */
+abstract class GeoShapeCellValues extends AbstractSortingNumericDocValues {
+    private final GeoShapeValue geoShapeValue;
+    protected int precision;
+    protected final GeoShapeCellIdSource.GeoShapeLongEncoder encoder;
+
+    public GeoShapeCellValues(GeoShapeValue geoShapeValue, int precision, GeoShapeCellIdSource.GeoShapeLongEncoder encoder) {
+        this.geoShapeValue = geoShapeValue;
+        this.precision = precision;
+        this.encoder = encoder;
+    }
+
+    @Override
+    public boolean advanceExact(int docId) throws IOException {
+        if (geoShapeValue.advanceExact(docId)) {
+            final GeoShapeDocValue geoShapeDocValue = geoShapeValue.nextValue();
+            relateShape(geoShapeDocValue);
+            sort();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * This function relates the shape's with the grid, and then put the intersecting grid's info as long, which
+     * can be iterated in the aggregation. It uses the encoder to find the relation.
+     *
+     * @param geoShapeDocValue {@link GeoShapeDocValue}
+     */
+    abstract void relateShape(final GeoShapeDocValue geoShapeDocValue);
+
+    /**
+     * Provides the {@link GeoShapeCellValues} for the input bounding box.
+     * @opensearch.internal
+     */
+    static class BoundedCellValues extends GeoShapeCellValues {
+        private final Rectangle geoBoundingBox;
+
+        public BoundedCellValues(
+            final GeoShapeValue geoShapeValue,
+            final int precision,
+            final GeoShapeCellIdSource.GeoShapeLongEncoder encoder,
+            final GeoBoundingBox boundingBox
+        ) {
+            super(geoShapeValue, precision, encoder);
+            this.geoBoundingBox = new Rectangle(boundingBox.left(), boundingBox.right(), boundingBox.top(), boundingBox.bottom());
+        }
+
+        /**
+         * This function relates the shape's with the grid, and then put the intersecting grid's info as long, which
+         * can be iterated in the aggregation. It uses the encoder to find the relation.
+         *
+         * @param geoShapeDocValue {@link GeoShapeDocValue}
+         */
+        @Override
+        void relateShape(final GeoShapeDocValue geoShapeDocValue) {
+            if (geoShapeDocValue.isIntersectingRectangle(geoBoundingBox)) {
+                // now we know the shape is in the bounding rectangle, we need add them in longValues
+                // generate all grid that this shape intersects
+                final List<Long> encodedValues = encoder.encode(geoShapeDocValue, precision);
+                resize(encodedValues.size());
+                for (int i = 0; i < encodedValues.size(); i++) {
+                    values[i] = encodedValues.get(i);
+                }
+            } else {
+                // As the shape is not intersecting with GeoBounding box, we need to reset the GeoShapeCellValues
+                // calling this function resets the CellValues for the current shape.
+                resize(0);
+            }
+        }
+
+    }
+
+    /**
+     * Provides the {@link GeoShapeCellValues} for unbounded cells
+     * @opensearch.internal
+     */
+    static class UnboundedCellValues extends GeoShapeCellValues {
+
+        public UnboundedCellValues(
+            final GeoShapeValue geoShapeValue,
+            final int precision,
+            final GeoShapeCellIdSource.GeoShapeLongEncoder encoder
+        ) {
+            super(geoShapeValue, precision, encoder);
+        }
+
+        /**
+         * This function relates the shape's with the grid, and then put the intersecting grid's info as long, which
+         * can be iterated in the aggregation. It uses the encoder to find the relation.
+         *
+         * @param geoShapeDocValue {@link GeoShapeDocValue}
+         */
+        @Override
+        void relateShape(final GeoShapeDocValue geoShapeDocValue) {
+            final List<Long> encodedValues = encoder.encode(geoShapeDocValue, precision);
+            resize(encodedValues.size());
+            for (int i = 0; i < encodedValues.size(); i++) {
+                values[i] = encodedValues.get(i);
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/UnboundedCellValues.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/UnboundedCellValues.java
similarity index 94%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/UnboundedCellValues.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/UnboundedCellValues.java
index 7dd7f155fb46e..0a520c7162002 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/UnboundedCellValues.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/UnboundedCellValues.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
 
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
@@ -37,6 +37,8 @@
 /**
  * Class representing {@link CellValues} that are unbounded by any
  * {@link GeoBoundingBox}.
+ *
+ * @opensearch.internal
  */
 class UnboundedCellValues extends CellValues {
 
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/package-info.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/package-info.java
new file mode 100644
index 0000000000000..16a5dd11f6210
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/cells/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * A Cells package which provide the different grid cells related functionalities for different aggregations
+ */
+package org.opensearch.geo.search.aggregations.bucket.geogrid.cells;
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/package-info.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/package-info.java
new file mode 100644
index 0000000000000..d9183a0f742ef
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** geo_grid Aggregation package. */
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/util/GeoShapeHashUtil.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/util/GeoShapeHashUtil.java
new file mode 100644
index 0000000000000..aefb31e623bb5
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/bucket/geogrid/util/GeoShapeHashUtil.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.geogrid.util;
+
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.geometry.utils.Geohash;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * We have a {@link Geohash} class present at the libs level, not using that because while encoding the shapes we need
+ * {@link GeoShapeDocValue}. This class provided the utilities encode the shape as GeoHashes
+ */
+public class GeoShapeHashUtil {
+
+    /**
+     * The function encodes the shape provided as {@link GeoShapeDocValue} to a {@link List} of {@link Long} values
+     * (representing the GeoHashes) which are intersecting with the shapes at a given precision.
+     *
+     * @param geoShapeDocValue {@link GeoShapeDocValue}
+     * @param precision int
+     * @return {@link List} containing encoded {@link Long} values
+     */
+    public static List<Long> encodeShape(final GeoShapeDocValue geoShapeDocValue, final int precision) {
+        final List<Long> encodedValues = new ArrayList<>();
+        final GeoShapeDocValue.BoundingRectangle boundingRectangle = geoShapeDocValue.getBoundingRectangle();
+        long topLeftGeoHash = Geohash.longEncode(boundingRectangle.getMinX(), boundingRectangle.getMaxY(), precision);
+        long topRightGeoHash = Geohash.longEncode(boundingRectangle.getMaxX(), boundingRectangle.getMaxY(), precision);
+        long bottomRightGeoHash = Geohash.longEncode(boundingRectangle.getMaxX(), boundingRectangle.getMinY(), precision);
+
+        long currentValue = topLeftGeoHash;
+        long rightMax = topRightGeoHash;
+        long tempCurrent = currentValue;
+        while (true) {
+            // check if this currentValue intersect with shape.
+            final Rectangle geohashRectangle = Geohash.toBoundingBox(Geohash.stringEncode(tempCurrent));
+            if (geoShapeDocValue.isIntersectingRectangle(geohashRectangle)) {
+                encodedValues.add(tempCurrent);
+            }
+
+            // Breaking condition
+            if (tempCurrent == bottomRightGeoHash) {
+                break;
+            }
+            // now change the iterator => tempCurrent
+            if (tempCurrent == rightMax) {
+                // move to next row
+                tempCurrent = Geohash.longEncode(Geohash.getNeighbor(Geohash.stringEncode(currentValue), precision, 0, -1));
+                currentValue = tempCurrent;
+                // update right max
+                rightMax = Geohash.longEncode(Geohash.getNeighbor(Geohash.stringEncode(rightMax), precision, 0, -1));
+            } else {
+                // move to next column
+                tempCurrent = Geohash.longEncode(Geohash.getNeighbor(Geohash.stringEncode(tempCurrent), precision, 1, 0));
+            }
+        }
+        return encodedValues;
+    }
+}
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoBoundsAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoBoundsAggregator.java
new file mode 100644
index 0000000000000..4a39fa1da04eb
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/AbstractGeoBoundsAggregator.java
@@ -0,0 +1,128 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.DoubleArray;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.metrics.MetricsAggregator;
+import org.opensearch.search.aggregations.support.ValuesSource;
+import org.opensearch.search.aggregations.support.ValuesSourceConfig;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Abstract class for doing the {@link GeoBounds} Aggregation over fields of type geo_shape and geo_point.
+ *
+ * @param <T> Class extending the {@link ValuesSource} which will provide the data on which aggregation will happen.
+ * @opensearch.internal
+ */
+public abstract class AbstractGeoBoundsAggregator<T extends ValuesSource> extends MetricsAggregator {
+
+    protected final T valuesSource;
+    protected final boolean wrapLongitude;
+    protected DoubleArray tops;
+    protected DoubleArray bottoms;
+    protected DoubleArray posLefts;
+    protected DoubleArray posRights;
+    protected DoubleArray negLefts;
+    protected DoubleArray negRights;
+
+    @SuppressWarnings("unchecked")
+    protected AbstractGeoBoundsAggregator(
+        String name,
+        SearchContext searchContext,
+        Aggregator aggregator,
+        ValuesSourceConfig valuesSourceConfig,
+        boolean wrapLongitude,
+        Map<String, Object> metaData
+    ) throws IOException {
+        super(name, searchContext, aggregator, metaData);
+        this.wrapLongitude = wrapLongitude;
+        valuesSource = valuesSourceConfig.hasValues() ? (T) valuesSourceConfig.getValuesSource() : null;
+
+        if (valuesSource != null) {
+            final BigArrays bigArrays = context.bigArrays();
+            tops = bigArrays.newDoubleArray(1, false);
+            tops.fill(0, tops.size(), Double.NEGATIVE_INFINITY);
+            bottoms = bigArrays.newDoubleArray(1, false);
+            bottoms.fill(0, bottoms.size(), Double.POSITIVE_INFINITY);
+            posLefts = bigArrays.newDoubleArray(1, false);
+            posLefts.fill(0, posLefts.size(), Double.POSITIVE_INFINITY);
+            posRights = bigArrays.newDoubleArray(1, false);
+            posRights.fill(0, posRights.size(), Double.NEGATIVE_INFINITY);
+            negLefts = bigArrays.newDoubleArray(1, false);
+            negLefts.fill(0, negLefts.size(), Double.POSITIVE_INFINITY);
+            negRights = bigArrays.newDoubleArray(1, false);
+            negRights.fill(0, negRights.size(), Double.NEGATIVE_INFINITY);
+        }
+    }
+
+    /**
+     * Build an empty aggregation.
+     */
+    @Override
+    public InternalAggregation buildEmptyAggregation() {
+        return new InternalGeoBounds(
+            name,
+            Double.NEGATIVE_INFINITY,
+            Double.POSITIVE_INFINITY,
+            Double.POSITIVE_INFINITY,
+            Double.NEGATIVE_INFINITY,
+            Double.POSITIVE_INFINITY,
+            Double.NEGATIVE_INFINITY,
+            wrapLongitude,
+            metadata()
+        );
+    }
+
+    /**
+     * Build an aggregation for data that has been collected into owningBucketOrd.
+     */
+    @Override
+    public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
+        if (valuesSource == null) {
+            return buildEmptyAggregation();
+        }
+        double top = tops.get(owningBucketOrdinal);
+        double bottom = bottoms.get(owningBucketOrdinal);
+        double posLeft = posLefts.get(owningBucketOrdinal);
+        double posRight = posRights.get(owningBucketOrdinal);
+        double negLeft = negLefts.get(owningBucketOrdinal);
+        double negRight = negRights.get(owningBucketOrdinal);
+        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, metadata());
+    }
+
+    @Override
+    public void doClose() {
+        Releasables.close(tops, bottoms, posLefts, posRights, negLefts, negRights);
+    }
+
+    protected void setBucketSize(final long bucket, final BigArrays bigArrays) {
+        if (bucket >= tops.size()) {
+            long from = tops.size();
+            tops = bigArrays.grow(tops, bucket + 1);
+            tops.fill(from, tops.size(), Double.NEGATIVE_INFINITY);
+            bottoms = bigArrays.resize(bottoms, tops.size());
+            bottoms.fill(from, bottoms.size(), Double.POSITIVE_INFINITY);
+            posLefts = bigArrays.resize(posLefts, tops.size());
+            posLefts.fill(from, posLefts.size(), Double.POSITIVE_INFINITY);
+            posRights = bigArrays.resize(posRights, tops.size());
+            posRights.fill(from, posRights.size(), Double.NEGATIVE_INFINITY);
+            negLefts = bigArrays.resize(negLefts, tops.size());
+            negLefts.fill(from, negLefts.size(), Double.POSITIVE_INFINITY);
+            negRights = bigArrays.resize(negRights, tops.size());
+            negRights.fill(from, negRights.size(), Double.NEGATIVE_INFINITY);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBounds.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBounds.java
similarity index 94%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBounds.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBounds.java
index ba0e115c383dc..81ef502dda130 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBounds.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBounds.java
@@ -30,13 +30,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.search.aggregations.Aggregation;
 
 /**
  * An aggregation that computes a bounding box in which all documents of the current bucket are.
+ *
+ * @opensearch.internal
  */
 public interface GeoBounds extends Aggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregationBuilder.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilder.java
similarity index 88%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregationBuilder.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilder.java
index 30ba6988325e6..f959c6bd6842c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregationBuilder.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilder.java
@@ -30,16 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.AggregatorFactory;
+import org.opensearch.search.aggregations.metrics.GeoBoundsAggregatorSupplier;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.opensearch.search.aggregations.support.ValuesSourceConfig;
@@ -50,8 +52,14 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for geo_bounds agg
+ *
+ * @opensearch.internal
+ */
 public class GeoBoundsAggregationBuilder extends ValuesSourceAggregationBuilder<GeoBoundsAggregationBuilder> {
     public static final String NAME = "geo_bounds";
+    private static final ParseField WRAP_LONGITUDE_FIELD = new ParseField("wrap_longitude");
     public static final ValuesSourceRegistry.RegistryKey<GeoBoundsAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
         NAME,
         GeoBoundsAggregatorSupplier.class
@@ -63,7 +71,7 @@ public class GeoBoundsAggregationBuilder extends ValuesSourceAggregationBuilder<
     );
     static {
         ValuesSourceAggregationBuilder.declareFields(PARSER, false, false, false);
-        PARSER.declareBoolean(GeoBoundsAggregationBuilder::wrapLongitude, GeoBoundsAggregator.WRAP_LONGITUDE_FIELD);
+        PARSER.declareBoolean(GeoBoundsAggregationBuilder::wrapLongitude, WRAP_LONGITUDE_FIELD);
     }
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -116,13 +124,6 @@ public GeoBoundsAggregationBuilder wrapLongitude(boolean wrapLongitude) {
         return this;
     }
 
-    /**
-     * Get whether to wrap longitudes.
-     */
-    public boolean wrapLongitude() {
-        return wrapLongitude;
-    }
-
     @Override
     public BucketCardinality bucketCardinality() {
         return BucketCardinality.NONE;
@@ -140,7 +141,7 @@ protected GeoBoundsAggregatorFactory innerBuild(
 
     @Override
     public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
-        builder.field(GeoBoundsAggregator.WRAP_LONGITUDE_FIELD.getPreferredName(), wrapLongitude);
+        builder.field(WRAP_LONGITUDE_FIELD.getPreferredName(), wrapLongitude);
         return builder;
     }
 
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregator.java
new file mode 100644
index 0000000000000..a6518ea702be6
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregator.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.index.fielddata.MultiGeoPointValues;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.LeafBucketCollector;
+import org.opensearch.search.aggregations.LeafBucketCollectorBase;
+import org.opensearch.search.aggregations.support.ValuesSource;
+import org.opensearch.search.aggregations.support.ValuesSourceConfig;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Aggregate all docs into a geographic bounds for field GeoPoint.
+ *
+ * @opensearch.internal
+ */
+final class GeoBoundsAggregator extends AbstractGeoBoundsAggregator<ValuesSource.GeoPoint> {
+
+    GeoBoundsAggregator(
+        String name,
+        SearchContext aggregationContext,
+        Aggregator parent,
+        ValuesSourceConfig valuesSourceConfig,
+        boolean wrapLongitude,
+        Map<String, Object> metadata
+    ) throws IOException {
+        super(name, aggregationContext, parent, valuesSourceConfig, wrapLongitude, metadata);
+    }
+
+    @Override
+    public LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCollector sub) {
+        if (valuesSource == null) {
+            return LeafBucketCollector.NO_OP_COLLECTOR;
+        }
+        final BigArrays bigArrays = context.bigArrays();
+        final MultiGeoPointValues values = valuesSource.geoPointValues(ctx);
+        return new LeafBucketCollectorBase(sub, values) {
+            @Override
+            public void collect(int doc, long bucket) throws IOException {
+                setBucketSize(bucket, bigArrays);
+
+                if (values.advanceExact(doc)) {
+                    final int valuesCount = values.docValueCount();
+                    for (int i = 0; i < valuesCount; ++i) {
+                        GeoPoint value = values.nextValue();
+                        double top = tops.get(bucket);
+                        if (value.lat() > top) {
+                            top = value.lat();
+                        }
+                        double bottom = bottoms.get(bucket);
+                        if (value.lat() < bottom) {
+                            bottom = value.lat();
+                        }
+                        double posLeft = posLefts.get(bucket);
+                        if (value.lon() >= 0 && value.lon() < posLeft) {
+                            posLeft = value.lon();
+                        }
+                        double posRight = posRights.get(bucket);
+                        if (value.lon() >= 0 && value.lon() > posRight) {
+                            posRight = value.lon();
+                        }
+                        double negLeft = negLefts.get(bucket);
+                        if (value.lon() < 0 && value.lon() < negLeft) {
+                            negLeft = value.lon();
+                        }
+                        double negRight = negRights.get(bucket);
+                        if (value.lon() < 0 && value.lon() > negRight) {
+                            negRight = value.lon();
+                        }
+                        tops.set(bucket, top);
+                        bottoms.set(bucket, bottom);
+                        posLefts.set(bucket, posLeft);
+                        posRights.set(bucket, posRight);
+                        negLefts.set(bucket, negLeft);
+                        negRights.set(bucket, negRight);
+                    }
+                }
+            }
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorFactory.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorFactory.java
similarity index 89%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorFactory.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorFactory.java
index 27744a549c748..fc9cce3cf98c1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorFactory.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorFactory.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.Aggregator;
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for geo_bounds agg
+ *
+ * @opensearch.internal
+ */
 class GeoBoundsAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final boolean wrapLongitude;
@@ -82,5 +87,11 @@ protected Aggregator doCreateInternal(
 
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(GeoBoundsAggregationBuilder.REGISTRY_KEY, CoreValuesSourceType.GEOPOINT, GeoBoundsAggregator::new, true);
+        builder.register(GeoBoundsAggregationBuilder.REGISTRY_KEY, CoreValuesSourceType.GEO_SHAPE, GeoBoundsGeoShapeAggregator::new, true);
+    }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
     }
 }
diff --git a/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregator.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregator.java
new file mode 100644
index 0000000000000..918b9a6701490
--- /dev/null
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregator.java
@@ -0,0 +1,116 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.index.LeafReaderContext;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.index.fielddata.GeoShapeValue;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.LeafBucketCollector;
+import org.opensearch.search.aggregations.LeafBucketCollectorBase;
+import org.opensearch.search.aggregations.support.ValuesSource;
+import org.opensearch.search.aggregations.support.ValuesSourceConfig;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Aggregate all docs into a geographic bounds for field geo_shape.
+ *
+ * @opensearch.internal
+ */
+public final class GeoBoundsGeoShapeAggregator extends AbstractGeoBoundsAggregator<ValuesSource.GeoShape> {
+    private static final Logger LOGGER = LogManager.getLogger(GeoBoundsGeoShapeAggregator.class);
+
+    public GeoBoundsGeoShapeAggregator(
+        String name,
+        SearchContext searchContext,
+        Aggregator aggregator,
+        ValuesSourceConfig valuesSourceConfig,
+        boolean wrapLongitude,
+        Map<String, Object> metaData
+    ) throws IOException {
+        super(name, searchContext, aggregator, valuesSourceConfig, wrapLongitude, metaData);
+    }
+
+    @Override
+    protected LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCollector leafBucketCollector) {
+        if (valuesSource == null) {
+            return LeafBucketCollector.NO_OP_COLLECTOR;
+        }
+        final BigArrays bigArrays = context.bigArrays();
+        final GeoShapeValue values = valuesSource.getGeoShapeValues(ctx);
+        return new LeafBucketCollectorBase(leafBucketCollector, values) {
+            @Override
+            public void collect(int doc, long bucket) throws IOException {
+                setBucketSize(bucket, bigArrays);
+                if (values.advanceExact(doc)) {
+                    final GeoShapeDocValue value = values.nextValue();
+                    final GeoShapeDocValue.BoundingRectangle boundingBox = value.getBoundingRectangle();
+                    if (boundingBox != null) {
+                        double top = tops.get(bucket);
+                        if (boundingBox.getMaxLatitude() > top) {
+                            top = boundingBox.getMaxLatitude();
+                        }
+
+                        double bottom = bottoms.get(bucket);
+                        if (boundingBox.getMinLatitude() < bottom) {
+                            bottom = boundingBox.getMinLatitude();
+                        }
+
+                        double posLeft = posLefts.get(bucket);
+                        if (boundingBox.getMinLongitude() >= 0 && boundingBox.getMinLongitude() < posLeft) {
+                            posLeft = boundingBox.getMinLongitude();
+                        }
+                        if (boundingBox.getMaxLongitude() >= 0 && boundingBox.getMaxLongitude() < posLeft) {
+                            posLeft = boundingBox.getMaxLongitude();
+                        }
+
+                        double posRight = posRights.get(bucket);
+                        if (boundingBox.getMaxLongitude() >= 0 && boundingBox.getMaxLongitude() > posRight) {
+                            posRight = boundingBox.getMaxLongitude();
+                        }
+                        if (boundingBox.getMinLongitude() >= 0 && boundingBox.getMinLongitude() > posRight) {
+                            posRight = boundingBox.getMinLongitude();
+                        }
+
+                        double negLeft = negLefts.get(bucket);
+                        if (boundingBox.getMinLongitude() < 0 && boundingBox.getMinLongitude() < negLeft) {
+                            negLeft = boundingBox.getMinLongitude();
+                        }
+                        if (boundingBox.getMaxLongitude() < 0 && boundingBox.getMaxLongitude() < negLeft) {
+                            negLeft = boundingBox.getMaxLongitude();
+                        }
+
+                        double negRight = negRights.get(bucket);
+                        if (boundingBox.getMaxLongitude() < 0 && boundingBox.getMaxLongitude() > negRight) {
+                            negRight = boundingBox.getMaxLongitude();
+                        }
+                        if (boundingBox.getMinLongitude() < 0 && boundingBox.getMinLongitude() > negRight) {
+                            negRight = boundingBox.getMinLongitude();
+                        }
+
+                        tops.set(bucket, top);
+                        bottoms.set(bucket, bottom);
+                        posLefts.set(bucket, posLeft);
+                        posRights.set(bucket, posRight);
+                        negLefts.set(bucket, negLeft);
+                        negRights.set(bucket, negRight);
+                    } else {
+                        LOGGER.error("The bounding box was null for the Doc id {}", doc);
+                    }
+                }
+            }
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoBounds.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBounds.java
similarity index 96%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoBounds.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBounds.java
index 84a46ed6c71d6..c3cb47d244c6b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoBounds.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBounds.java
@@ -30,13 +30,13 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 
 import java.io.IOException;
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of geo bounds agg
+ *
+ * @opensearch.internal
+ */
 public class InternalGeoBounds extends InternalAggregation implements GeoBounds {
     public final double top;
     public final double bottom;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoBounds.java b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/ParsedGeoBounds.java
similarity index 90%
rename from server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoBounds.java
rename to modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/ParsedGeoBounds.java
index e0c734e4dc8c5..d40bec096ed01 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoBounds.java
+++ b/modules/geo/src/main/java/org/opensearch/geo/search/aggregations/metrics/ParsedGeoBounds.java
@@ -30,16 +30,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
@@ -49,8 +49,13 @@
 import static org.opensearch.common.geo.GeoBoundingBox.LAT_FIELD;
 import static org.opensearch.common.geo.GeoBoundingBox.LON_FIELD;
 import static org.opensearch.common.geo.GeoBoundingBox.TOP_LEFT_FIELD;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * A geo bounds agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoBounds extends ParsedAggregation implements GeoBounds {
 
     // A top of Double.NEGATIVE_INFINITY yields an empty xContent, so the bounding box is null
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridAggregationBuilderTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridAggregationBuilderTests.java
new file mode 100644
index 0000000000000..55c82351dbab4
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoHashGridAggregationBuilderTests.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.BaseAggregationTestCase;
+import org.opensearch.test.VersionUtils;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class GeoHashGridAggregationBuilderTests extends BaseAggregationTestCase<GeoGridAggregationBuilder> {
+
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singletonList(GeoModulePlugin.class);
+    }
+
+    @Override
+    protected GeoHashGridAggregationBuilder createTestAggregatorBuilder() {
+        String name = randomAlphaOfLengthBetween(3, 20);
+        GeoHashGridAggregationBuilder factory = new GeoHashGridAggregationBuilder(name);
+        factory.field("foo");
+        if (randomBoolean()) {
+            int precision = randomIntBetween(1, 12);
+            factory.precision(precision);
+        }
+        if (randomBoolean()) {
+            factory.size(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.shardSize(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.setGeoBoundingBox(RandomGeoGenerator.randomBBox());
+        }
+        return factory;
+    }
+
+    public void testSerializationPreBounds() throws Exception {
+        Version noBoundsSupportVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_0);
+        GeoHashGridAggregationBuilder builder = createTestAggregatorBuilder();
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            output.setVersion(LegacyESVersion.V_7_6_0);
+            builder.writeTo(output);
+            try (
+                StreamInput in = new NamedWriteableAwareStreamInput(
+                    output.bytes().streamInput(),
+                    new NamedWriteableRegistry(Collections.emptyList())
+                )
+            ) {
+                in.setVersion(noBoundsSupportVersion);
+                GeoHashGridAggregationBuilder readBuilder = new GeoHashGridAggregationBuilder(in);
+                assertThat(
+                    readBuilder.geoBoundingBox(),
+                    equalTo(new GeoBoundingBox(new GeoPoint(Double.NaN, Double.NaN), new GeoPoint(Double.NaN, Double.NaN)))
+                );
+            }
+        }
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridAggregationBuilderTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridAggregationBuilderTests.java
new file mode 100644
index 0000000000000..c1c97cf18847c
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/GeoTileGridAggregationBuilderTests.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket;
+
+import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.BaseAggregationTestCase;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.test.VersionUtils;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class GeoTileGridAggregationBuilderTests extends BaseAggregationTestCase<GeoGridAggregationBuilder> {
+
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singletonList(GeoModulePlugin.class);
+    }
+
+    @Override
+    protected GeoTileGridAggregationBuilder createTestAggregatorBuilder() {
+        String name = randomAlphaOfLengthBetween(3, 20);
+        GeoTileGridAggregationBuilder factory = new GeoTileGridAggregationBuilder(name);
+        factory.field("foo");
+        if (randomBoolean()) {
+            factory.precision(randomIntBetween(0, GeoTileUtils.MAX_ZOOM));
+        }
+        if (randomBoolean()) {
+            factory.size(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.shardSize(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.setGeoBoundingBox(RandomGeoGenerator.randomBBox());
+        }
+        return factory;
+    }
+
+    public void testSerializationPreBounds() throws Exception {
+        Version noBoundsSupportVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_0);
+        GeoTileGridAggregationBuilder builder = createTestAggregatorBuilder();
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            output.setVersion(LegacyESVersion.V_7_6_0);
+            builder.writeTo(output);
+            try (
+                StreamInput in = new NamedWriteableAwareStreamInput(
+                    output.bytes().streamInput(),
+                    new NamedWriteableRegistry(Collections.emptyList())
+                )
+            ) {
+                in.setVersion(noBoundsSupportVersion);
+                GeoTileGridAggregationBuilder readBuilder = new GeoTileGridAggregationBuilder(in);
+                assertThat(
+                    readBuilder.geoBoundingBox(),
+                    equalTo(new GeoBoundingBox(new GeoPoint(Double.NaN, Double.NaN), new GeoPoint(Double.NaN, Double.NaN)))
+                );
+            }
+        }
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridAggregationCompositeAggregatorTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridAggregationCompositeAggregatorTests.java
new file mode 100644
index 0000000000000..f46bef97194ef
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridAggregationCompositeAggregatorTests.java
@@ -0,0 +1,174 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.composite;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.LatLonPoint;
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.search.DocValuesFieldExistsQuery;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregator;
+import org.opensearch.index.mapper.GeoPointFieldMapper;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder;
+import org.opensearch.search.aggregations.composite.BaseCompositeAggregatorTestCase;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Testing the {@link GeoTileGridAggregator} as part of CompositeAggregation.
+ */
+public class GeoTileGridAggregationCompositeAggregatorTests extends BaseCompositeAggregatorTestCase {
+
+    protected List<SearchPlugin> getSearchPlugins() {
+        return Collections.singletonList(new GeoModulePlugin());
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        FIELD_TYPES.add(new GeoPointFieldMapper.GeoPointFieldType("geo_point"));
+    }
+
+    public void testUnmappedFieldWithGeopoint() throws Exception {
+        final List<Map<String, List<Object>>> dataset = new ArrayList<>();
+        final String mappedFieldName = "geo_point";
+        dataset.addAll(
+            Arrays.asList(
+                createDocument(mappedFieldName, new GeoPoint(48.934059, 41.610741)),
+                createDocument(mappedFieldName, new GeoPoint(-23.065941, 113.610741)),
+                createDocument(mappedFieldName, new GeoPoint(90.0, 0.0)),
+                createDocument(mappedFieldName, new GeoPoint(37.2343, -115.8067)),
+                createDocument(mappedFieldName, new GeoPoint(90.0, 0.0))
+            )
+        );
+
+        // just unmapped = no results
+        testSearchCase(
+            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
+            dataset,
+            () -> new CompositeAggregationBuilder("name", Arrays.asList(new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped"))),
+            (result) -> assertEquals(0, result.getBuckets().size())
+        );
+
+        // unmapped missing bucket = one result
+        testSearchCase(
+            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
+            dataset,
+            () -> new CompositeAggregationBuilder(
+                "name",
+                Arrays.asList(new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped").missingBucket(true))
+            ),
+            (result) -> {
+                assertEquals(1, result.getBuckets().size());
+                assertEquals("{unmapped=null}", result.afterKey().toString());
+                assertEquals("{unmapped=null}", result.getBuckets().get(0).getKeyAsString());
+                assertEquals(5L, result.getBuckets().get(0).getDocCount());
+            }
+        );
+
+        // field + unmapped, no missing bucket = no results
+        testSearchCase(
+            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
+            dataset,
+            () -> new CompositeAggregationBuilder(
+                "name",
+                Arrays.asList(
+                    new GeoTileGridValuesSourceBuilder(mappedFieldName).field(mappedFieldName),
+                    new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped")
+                )
+            ),
+            (result) -> assertEquals(0, result.getBuckets().size())
+        );
+
+        // field + unmapped with missing bucket = multiple results
+        testSearchCase(
+            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
+            dataset,
+            () -> new CompositeAggregationBuilder(
+                "name",
+                Arrays.asList(
+                    new GeoTileGridValuesSourceBuilder(mappedFieldName).field(mappedFieldName),
+                    new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped").missingBucket(true)
+                )
+            ),
+            (result) -> {
+                assertEquals(2, result.getBuckets().size());
+                assertEquals("{geo_point=7/64/56, unmapped=null}", result.afterKey().toString());
+                assertEquals("{geo_point=7/32/56, unmapped=null}", result.getBuckets().get(0).getKeyAsString());
+                assertEquals(2L, result.getBuckets().get(0).getDocCount());
+                assertEquals("{geo_point=7/64/56, unmapped=null}", result.getBuckets().get(1).getKeyAsString());
+                assertEquals(3L, result.getBuckets().get(1).getDocCount());
+            }
+        );
+
+    }
+
+    public void testWithGeoPoint() throws Exception {
+        final List<Map<String, List<Object>>> dataset = new ArrayList<>();
+        dataset.addAll(
+            Arrays.asList(
+                createDocument("geo_point", new GeoPoint(48.934059, 41.610741)),
+                createDocument("geo_point", new GeoPoint(-23.065941, 113.610741)),
+                createDocument("geo_point", new GeoPoint(90.0, 0.0)),
+                createDocument("geo_point", new GeoPoint(37.2343, -115.8067)),
+                createDocument("geo_point", new GeoPoint(90.0, 0.0))
+            )
+        );
+        testSearchCase(Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery("geo_point")), dataset, () -> {
+            GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder("geo_point").field("geo_point");
+            return new CompositeAggregationBuilder("name", Collections.singletonList(geoTile));
+        }, (result) -> {
+            assertEquals(2, result.getBuckets().size());
+            assertEquals("{geo_point=7/64/56}", result.afterKey().toString());
+            assertEquals("{geo_point=7/32/56}", result.getBuckets().get(0).getKeyAsString());
+            assertEquals(2L, result.getBuckets().get(0).getDocCount());
+            assertEquals("{geo_point=7/64/56}", result.getBuckets().get(1).getKeyAsString());
+            assertEquals(3L, result.getBuckets().get(1).getDocCount());
+        });
+
+        testSearchCase(Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery("geo_point")), dataset, () -> {
+            GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder("geo_point").field("geo_point");
+            return new CompositeAggregationBuilder("name", Collections.singletonList(geoTile)).aggregateAfter(
+                Collections.singletonMap("geo_point", "7/32/56")
+            );
+        }, (result) -> {
+            assertEquals(1, result.getBuckets().size());
+            assertEquals("{geo_point=7/64/56}", result.afterKey().toString());
+            assertEquals("{geo_point=7/64/56}", result.getBuckets().get(0).getKeyAsString());
+            assertEquals(3L, result.getBuckets().get(0).getDocCount());
+        });
+    }
+
+    @Override
+    protected boolean addValueToDocument(final Document doc, final String name, final Object value) {
+        if (value instanceof GeoPoint) {
+            GeoPoint point = (GeoPoint) value;
+            doc.add(
+                new SortedNumericDocValuesField(
+                    name,
+                    GeoTileUtils.longEncode(point.lon(), point.lat(), GeoTileGridAggregationBuilder.DEFAULT_PRECISION)
+                )
+            );
+            doc.add(new LatLonPoint(name, point.lat(), point.lon()));
+            return true;
+        }
+        return false;
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridCompositeAggregationBuilderTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridCompositeAggregationBuilderTests.java
new file mode 100644
index 0000000000000..ea7a2a83945c2
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridCompositeAggregationBuilderTests.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.composite;
+
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.BaseAggregationTestCase;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceBuilder;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+public class GeoTileGridCompositeAggregationBuilderTests extends BaseAggregationTestCase<CompositeAggregationBuilder> {
+
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singletonList(GeoModulePlugin.class);
+    }
+
+    private GeoTileGridValuesSourceBuilder randomGeoTileGridValuesSourceBuilder() {
+        GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder(randomAlphaOfLengthBetween(5, 10));
+        if (randomBoolean()) {
+            geoTile.precision(randomIntBetween(0, GeoTileUtils.MAX_ZOOM));
+        }
+        if (randomBoolean()) {
+            geoTile.geoBoundingBox(RandomGeoGenerator.randomBBox());
+        }
+        return geoTile;
+    }
+
+    @Override
+    protected CompositeAggregationBuilder createTestAggregatorBuilder() {
+        int numSources = randomIntBetween(1, 10);
+        List<CompositeValuesSourceBuilder<?>> sources = new ArrayList<>();
+        for (int i = 0; i < numSources; i++) {
+            sources.add(randomGeoTileGridValuesSourceBuilder());
+        }
+        return new CompositeAggregationBuilder(randomAlphaOfLength(10), sources);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java
similarity index 85%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java
index 58199741b1ee2..a9e495c487ab0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/composite/GeoTileGridValuesSourceBuilderTests.java
@@ -30,17 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.composite;
+package org.opensearch.geo.search.aggregations.bucket.composite;
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.geo.GeoBoundingBox;
-import org.opensearch.common.geo.GeoBoundingBoxTests;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -60,7 +61,7 @@ public void testBWCBounds() throws IOException {
         Version noBoundsSupportVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_0);
         GeoTileGridValuesSourceBuilder builder = new GeoTileGridValuesSourceBuilder("name");
         if (randomBoolean()) {
-            builder.geoBoundingBox(GeoBoundingBoxTests.randomBBox());
+            builder.geoBoundingBox(RandomGeoGenerator.randomBBox());
         }
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             output.setVersion(LegacyESVersion.V_7_6_0);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java
similarity index 94%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java
index 17fddb8978499..75a3c5b2e38c1 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridAggregatorTestCase.java
@@ -29,7 +29,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.apache.lucene.document.LatLonDocValuesField;
 import org.apache.lucene.document.SortedSetDocValuesField;
@@ -37,25 +37,27 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.geo.GeoBoundingBox;
-import org.opensearch.common.geo.GeoBoundingBoxTests;
 import org.opensearch.common.geo.GeoUtils;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.tests.common.AggregationInspectionHelper;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorTestCase;
 import org.opensearch.search.aggregations.MultiBucketConsumerService;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
-import org.opensearch.search.aggregations.support.AggregationInspectionHelper;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -91,6 +93,16 @@ public abstract class GeoGridAggregatorTestCase<T extends InternalGeoGridBucket>
      */
     protected abstract GeoGridAggregationBuilder createBuilder(String name);
 
+    /**
+     * Overriding the Search Plugins list with {@link GeoModulePlugin} so that the testcase will know that this plugin is
+     * to be loaded during the tests.
+     * @return List of {@link SearchPlugin}
+     */
+    @Override
+    protected List<SearchPlugin> getSearchPlugins() {
+        return Collections.singletonList(new GeoModulePlugin());
+    }
+
     public void testNoDocs() throws IOException {
         testCase(
             new MatchAllDocsQuery(),
@@ -111,7 +123,9 @@ public void testUnmapped() throws IOException {
             randomPrecision(),
             null,
             geoGrid -> { assertEquals(0, geoGrid.getBuckets().size()); },
-            iw -> { iw.addDocument(Collections.singleton(new LatLonDocValuesField(FIELD_NAME, 10D, 10D))); }
+            iw -> {
+                iw.addDocument(Collections.singleton(new LatLonDocValuesField(FIELD_NAME, 10D, 10D)));
+            }
         );
     }
 
@@ -225,7 +239,7 @@ public void testBounds() throws IOException {
         // only consider bounding boxes that are at least GEOHASH_TOLERANCE wide and have quantized coordinates
         GeoBoundingBox bbox = randomValueOtherThanMany(
             (b) -> Math.abs(GeoUtils.normalizeLon(b.right()) - GeoUtils.normalizeLon(b.left())) < GEOHASH_TOLERANCE,
-            GeoBoundingBoxTests::randomBBox
+            RandomGeoGenerator::randomBBox
         );
         Function<Double, Double> encodeDecodeLat = (lat) -> GeoEncodingUtils.decodeLatitude(GeoEncodingUtils.encodeLatitude(lat));
         Function<Double, Double> encodeDecodeLon = (lon) -> GeoEncodingUtils.decodeLongitude(GeoEncodingUtils.encodeLongitude(lon));
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridTestCase.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridTestCase.java
similarity index 79%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridTestCase.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridTestCase.java
index ce286a4443660..cb61ff77dde08 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoGridTestCase.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoGridTestCase.java
@@ -29,9 +29,16 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.apache.lucene.index.IndexWriter;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.search.aggregations.metrics.ParsedGeoBounds;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 import org.opensearch.test.InternalMultiBucketAggregationTestCase;
@@ -76,6 +83,36 @@ protected int maxNumberOfBuckets() {
         return 3;
     }
 
+    /**
+     * Overriding the method so that tests can get the aggregation specs for namedWriteable.
+     *
+     * @return GeoPlugin
+     */
+    @Override
+    protected SearchPlugin registerPlugin() {
+        return new GeoModulePlugin();
+    }
+
+    /**
+     * Overriding with the {@link ParsedGeoBounds} so that it can be parsed. We need to do this as {@link GeoModulePlugin}
+     * is registering this Aggregation.
+     *
+     * @return a List of {@link NamedXContentRegistry.Entry}
+     */
+    @Override
+    protected List<NamedXContentRegistry.Entry> getNamedXContents() {
+        final List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(getDefaultNamedXContents());
+        final ContextParser<Object, Aggregation> hashGridParser = (p, c) -> ParsedGeoHashGrid.fromXContent(p, (String) c);
+        final ContextParser<Object, Aggregation> geoTileParser = (p, c) -> ParsedGeoTileGrid.fromXContent(p, (String) c);
+        namedXContents.add(
+            new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(GeoHashGridAggregationBuilder.NAME), hashGridParser)
+        );
+        namedXContents.add(
+            new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(GeoTileGridAggregationBuilder.NAME), geoTileParser)
+        );
+        return namedXContents;
+    }
+
     @Override
     protected T createTestInstance(String name, Map<String, Object> metadata, InternalAggregations aggregations) {
         final int precision = randomPrecision();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java
similarity index 96%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java
index 5c63b15c7f614..04fa815366f6b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridAggregatorTests.java
@@ -30,7 +30,7 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import static org.opensearch.geometry.utils.Geohash.stringEncode;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java
similarity index 97%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java
index e81e22b3b562f..a195a1ade781a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridParserTests.java
@@ -29,21 +29,21 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
-
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geo.GeometryTestUtils;
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.test.OpenSearchTestCase;
 
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+
 public class GeoHashGridParserTests extends OpenSearchTestCase {
     public void testParseValidFromInts() throws Exception {
         int precision = randomIntBetween(1, 12);
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridTests.java
new file mode 100644
index 0000000000000..c84c6ef5ec076
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoHashGridTests.java
@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
+
+import org.opensearch.geometry.utils.Geohash;
+import org.opensearch.search.aggregations.InternalAggregations;
+
+import java.util.List;
+import java.util.Map;
+
+public class GeoHashGridTests extends GeoGridTestCase<InternalGeoHashGridBucket, InternalGeoHashGrid> {
+
+    @Override
+    protected InternalGeoHashGrid createInternalGeoGrid(
+        String name,
+        int size,
+        List<InternalGeoGridBucket> buckets,
+        Map<String, Object> metadata
+    ) {
+        return new InternalGeoHashGrid(name, size, buckets, metadata);
+    }
+
+    @Override
+    protected InternalGeoHashGridBucket createInternalGeoGridBucket(Long key, long docCount, InternalAggregations aggregations) {
+        return new InternalGeoHashGridBucket(key, docCount, aggregations);
+    }
+
+    @Override
+    protected long longEncode(double lng, double lat, int precision) {
+        return Geohash.longEncode(lng, lat, precision);
+    }
+
+    @Override
+    protected int randomPrecision() {
+        return randomIntBetween(4, 12);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java
similarity index 94%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java
index 4e88111ac2dfc..f2f641ea794c0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridAggregatorTests.java
@@ -30,7 +30,9 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
+
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 
 public class GeoTileGridAggregatorTests extends GeoGridAggregatorTestCase<InternalGeoTileGridBucket> {
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java
similarity index 95%
rename from server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java
index 567bcd57d23e5..02b7c10198d80 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridParserTests.java
@@ -29,14 +29,15 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
 
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geo.GeometryTestUtils;
 import org.opensearch.geometry.Rectangle;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.containsString;
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridTests.java
new file mode 100644
index 0000000000000..ead67e0455d94
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/bucket/geogrid/GeoTileGridTests.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.geo.search.aggregations.bucket.geogrid;
+
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
+
+import java.util.List;
+import java.util.Map;
+
+public class GeoTileGridTests extends GeoGridTestCase<InternalGeoTileGridBucket, InternalGeoTileGrid> {
+
+    @Override
+    protected InternalGeoTileGrid createInternalGeoGrid(
+        String name,
+        int size,
+        List<InternalGeoGridBucket> buckets,
+        Map<String, Object> metadata
+    ) {
+        return new InternalGeoTileGrid(name, size, buckets, metadata);
+    }
+
+    @Override
+    protected InternalGeoTileGridBucket createInternalGeoGridBucket(Long key, long docCount, InternalAggregations aggregations) {
+        return new InternalGeoTileGridBucket(key, docCount, aggregations);
+    }
+
+    @Override
+    protected long longEncode(double lng, double lat, int precision) {
+        return GeoTileUtils.longEncode(lng, lat, precision);
+    }
+
+    @Override
+    protected int randomPrecision() {
+        // precision values below 8 can lead to parsing errors
+        return randomIntBetween(8, GeoTileUtils.MAX_ZOOM);
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilderTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilderTests.java
new file mode 100644
index 0000000000000..49b455bbf389e
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregationBuilderTests.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.BaseAggregationTestCase;
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class GeoBoundsAggregationBuilderTests extends BaseAggregationTestCase<GeoBoundsAggregationBuilder> {
+
+    /**
+     * This registers the GeoShape mapper with the Tests so that it can be used for testing the aggregation builders
+     *
+     * @return A Collection containing {@link GeoModulePlugin}
+     */
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singletonList(GeoModulePlugin.class);
+    }
+
+    @Override
+    protected GeoBoundsAggregationBuilder createTestAggregatorBuilder() {
+        GeoBoundsAggregationBuilder factory = new GeoBoundsAggregationBuilder(randomAlphaOfLengthBetween(1, 20));
+        String field = randomAlphaOfLengthBetween(3, 20);
+        factory.field(field);
+        if (randomBoolean()) {
+            factory.wrapLongitude(randomBoolean());
+        }
+        if (randomBoolean()) {
+            factory.missing("0,0");
+        }
+        return factory;
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorTests.java
similarity index 88%
rename from server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorTests.java
index 6440c62e58e18..ee7a3c7e3faa2 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsAggregatorTests.java
@@ -30,26 +30,42 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.LatLonDocValuesField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.tests.common.AggregationInspectionHelper;
+import org.opensearch.geo.tests.common.RandomGeoGenerator;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.AggregatorTestCase;
-import org.opensearch.search.aggregations.support.AggregationInspectionHelper;
-import org.opensearch.test.geo.RandomGeoGenerator;
 
-import static org.opensearch.search.aggregations.metrics.InternalGeoBoundsTests.GEOHASH_TOLERANCE;
+import java.util.Collections;
+import java.util.List;
+
 import static org.hamcrest.Matchers.closeTo;
 
 public class GeoBoundsAggregatorTests extends AggregatorTestCase {
+    public static final double GEOHASH_TOLERANCE = 1E-5D;
+
+    /**
+     * Overriding the Search Plugins list with {@link GeoModulePlugin} so that the testcase will know that this plugin is
+     * to be loaded during the tests.
+     * @return List of {@link SearchPlugin}
+     */
+    @Override
+    protected List<SearchPlugin> getSearchPlugins() {
+        return Collections.singletonList(new GeoModulePlugin());
+    }
+
     public void testEmpty() throws Exception {
         try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir)) {
             GeoBoundsAggregationBuilder aggBuilder = new GeoBoundsAggregationBuilder("my_agg").field("field").wrapLongitude(false);
diff --git a/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregatorTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregatorTests.java
new file mode 100644
index 0000000000000..cd88635f6c5cc
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/GeoBoundsGeoShapeAggregatorTests.java
@@ -0,0 +1,237 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.search.aggregations.metrics;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.LatLonShape;
+import org.apache.lucene.document.ShapeDocValuesField;
+import org.apache.lucene.geo.LatLonGeometry;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.geo.GeoShapeUtils;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.geo.tests.common.AggregationInspectionHelper;
+import org.opensearch.geo.tests.common.RandomGeoGeometryGenerator;
+import org.opensearch.geometry.Circle;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.Line;
+import org.opensearch.geometry.Point;
+import org.opensearch.geometry.Polygon;
+import org.opensearch.geometry.ShapeType;
+import org.opensearch.index.mapper.GeoShapeFieldMapper;
+import org.opensearch.index.mapper.GeoShapeIndexer;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.search.aggregations.AggregatorTestCase;
+import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.MatcherAssert;
+import org.junit.Assert;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Random;
+
+import static org.hamcrest.Matchers.closeTo;
+
+public class GeoBoundsGeoShapeAggregatorTests extends AggregatorTestCase {
+    private static final Logger LOG = LogManager.getLogger(GeoBoundsGeoShapeAggregatorTests.class);
+    private static final double GEOHASH_TOLERANCE = 1E-5D;
+    private static final String AGGREGATION_NAME = "my_agg";
+    private static final String FIELD_NAME = "field";
+
+    /**
+     * Overriding the Search Plugins list with {@link GeoModulePlugin} so that the testcase will know that this plugin is
+     * to be loaded during the tests.
+     *
+     * @return List of {@link SearchPlugin}
+     */
+    @Override
+    protected List<SearchPlugin> getSearchPlugins() {
+        return Collections.singletonList(new GeoModulePlugin());
+    }
+
+    /**
+     * Testing Empty aggregator results.
+     *
+     * @throws Exception
+     */
+    public void testEmpty() throws Exception {
+        try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir)) {
+            final GeoBoundsAggregationBuilder aggBuilder = new GeoBoundsAggregationBuilder(AGGREGATION_NAME).field(FIELD_NAME)
+                .wrapLongitude(false);
+
+            final MappedFieldType fieldType = new GeoShapeFieldMapper.GeoShapeFieldType(FIELD_NAME);
+            try (IndexReader reader = w.getReader()) {
+                IndexSearcher searcher = new IndexSearcher(reader);
+                InternalGeoBounds bounds = searchAndReduce(searcher, new MatchAllDocsQuery(), aggBuilder, fieldType);
+                assertTrue(Double.isInfinite(bounds.top));
+                assertTrue(Double.isInfinite(bounds.bottom));
+                assertTrue(Double.isInfinite(bounds.posLeft));
+                assertTrue(Double.isInfinite(bounds.posRight));
+                assertTrue(Double.isInfinite(bounds.negLeft));
+                assertTrue(Double.isInfinite(bounds.negRight));
+                assertFalse(AggregationInspectionHelper.hasValue(bounds));
+            }
+        }
+    }
+
+    /**
+     * Testing GeoBoundAggregator for random shapes which are indexed.
+     *
+     * @throws Exception
+     */
+    public void testRandom() throws Exception {
+        final int numDocs = randomIntBetween(50, 100);
+        final List<Double> Y = new ArrayList<>();
+        final List<Double> X = new ArrayList<>();
+        final Random random = random();
+        try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random, dir)) {
+            for (int i = 0; i < numDocs; i++) {
+                final Document document = new Document();
+                final Geometry geometry = randomLuceneGeometry(random);
+                LOG.debug("Random Geometry created for Indexing : {}", geometry);
+                document.add(createShapeDocValue(geometry));
+                w.addDocument(document);
+                getAllXAndYPoints(geometry, X, Y);
+            }
+            final GeoBoundsAggregationBuilder aggBuilder = new GeoBoundsAggregationBuilder(AGGREGATION_NAME).field(FIELD_NAME)
+                .wrapLongitude(false);
+            final MappedFieldType fieldType = new GeoShapeFieldMapper.GeoShapeFieldType(FIELD_NAME);
+            try (IndexReader reader = w.getReader()) {
+                final IndexSearcher searcher = new IndexSearcher(reader);
+                final InternalGeoBounds actualBounds = searchAndReduce(searcher, new MatchAllDocsQuery(), aggBuilder, fieldType);
+                final GeoBoundingBox expectedGeoBounds = getExpectedGeoBounds(X, Y);
+                MatcherAssert.assertThat(
+                    actualBounds.bottomRight().getLat(),
+                    closeTo(expectedGeoBounds.bottomRight().getLat(), GEOHASH_TOLERANCE)
+                );
+                MatcherAssert.assertThat(
+                    actualBounds.bottomRight().getLon(),
+                    closeTo(expectedGeoBounds.bottomRight().getLon(), GEOHASH_TOLERANCE)
+                );
+                MatcherAssert.assertThat(actualBounds.topLeft().getLat(), closeTo(expectedGeoBounds.topLeft().getLat(), GEOHASH_TOLERANCE));
+                MatcherAssert.assertThat(actualBounds.topLeft().getLon(), closeTo(expectedGeoBounds.topLeft().getLon(), GEOHASH_TOLERANCE));
+                assertTrue(AggregationInspectionHelper.hasValue(actualBounds));
+            }
+        }
+    }
+
+    private GeoBoundingBox getExpectedGeoBounds(final List<Double> X, final List<Double> Y) {
+        double top = Double.NEGATIVE_INFINITY;
+        double bottom = Double.POSITIVE_INFINITY;
+        double posLeft = Double.POSITIVE_INFINITY;
+        double posRight = Double.NEGATIVE_INFINITY;
+        double negLeft = Double.POSITIVE_INFINITY;
+        double negRight = Double.NEGATIVE_INFINITY;
+        // Finding the bounding box for the shapes.
+        for (final Double lon : X) {
+            if (lon >= 0 && lon < posLeft) {
+                posLeft = lon;
+            }
+            if (lon >= 0 && lon > posRight) {
+                posRight = lon;
+            }
+            if (lon < 0 && lon < negLeft) {
+                negLeft = lon;
+            }
+            if (lon < 0 && lon > negRight) {
+                negRight = lon;
+            }
+        }
+        for (final Double lat : Y) {
+            if (lat > top) {
+                top = lat;
+            }
+            if (lat < bottom) {
+                bottom = lat;
+            }
+        }
+        if (Double.isInfinite(posLeft)) {
+            return new GeoBoundingBox(new GeoPoint(top, negLeft), new GeoPoint(bottom, negRight));
+        } else if (Double.isInfinite(negLeft)) {
+            return new GeoBoundingBox(new GeoPoint(top, posLeft), new GeoPoint(bottom, posRight));
+        } else {
+            return new GeoBoundingBox(new GeoPoint(top, negLeft), new GeoPoint(bottom, posRight));
+        }
+    }
+
+    private void getAllXAndYPoints(final Geometry geometry, final List<Double> X, final List<Double> Y) {
+        if (geometry instanceof Point) {
+            final Point point = (Point) geometry;
+            X.add(point.getX());
+            Y.add(point.getY());
+            return;
+        } else if (geometry instanceof Polygon) {
+            final Polygon polygon = (Polygon) geometry;
+            for (int i = 0; i < polygon.getPolygon().getX().length; i++) {
+                X.add(polygon.getPolygon().getX(i));
+                Y.add(polygon.getPolygon().getY(i));
+            }
+            return;
+        } else if (geometry instanceof Line) {
+            final Line line = (Line) geometry;
+            for (int i = 0; i < line.getX().length; i++) {
+                X.add(line.getX(i));
+                Y.add(line.getY(i));
+            }
+            return;
+        }
+        Assert.fail(
+            String.format(Locale.ROOT, "Error cannot convert the %s to a valid indexable format[POINT, POLYGON, LINE]", geometry.getClass())
+        );
+    }
+
+    private ShapeDocValuesField createShapeDocValue(final Geometry geometry) {
+        if (geometry instanceof Point) {
+            final Point point = (Point) geometry;
+            return LatLonShape.createDocValueField(FIELD_NAME, point.getLat(), point.getLon());
+        } else if (geometry instanceof Polygon) {
+            return LatLonShape.createDocValueField(FIELD_NAME, GeoShapeUtils.toLucenePolygon((Polygon) geometry));
+        } else if (geometry instanceof Line) {
+            return LatLonShape.createDocValueField(FIELD_NAME, GeoShapeUtils.toLuceneLine((Line) geometry));
+        }
+        Assert.fail(
+            String.format(Locale.ROOT, "Error cannot convert the %s to a valid indexable format[POINT, POLYGON, LINE]", geometry.getClass())
+        );
+        return null;
+    }
+
+    /**
+     * Random function to generate a {@link LatLonGeometry}. Now for indexing of GeoShape field, we index all the
+     * different Geometry shapes that we support({@link ShapeType}) in OpenSearch are broken down into 3 shapes only.
+     * Hence, we are generating only 3 shapes : {@link org.apache.lucene.geo.Point},
+     * {@link org.apache.lucene.geo.Line}, {@link org.apache.lucene.geo.Polygon}. {@link Circle} is not supported.
+     * Check {@link GeoShapeIndexer#prepareForIndexing(org.opensearch.geometry.Geometry)}
+     *
+     * @return {@link LatLonGeometry}
+     */
+    private static Geometry randomLuceneGeometry(final Random r) {
+        int shapeNumber = OpenSearchTestCase.randomIntBetween(0, 2);
+        if (shapeNumber == 0) {
+            // Point
+            return RandomGeoGeometryGenerator.randomPoint(r);
+        } else if (shapeNumber == 1) {
+            // LineString
+            return RandomGeoGeometryGenerator.randomLine(r);
+        } else {
+            // Polygon
+            return RandomGeoGeometryGenerator.randomPolygon(r);
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalGeoBoundsTests.java b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBoundsTests.java
similarity index 81%
rename from server/src/test/java/org/opensearch/search/aggregations/metrics/InternalGeoBoundsTests.java
rename to modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBoundsTests.java
index e3857efff5d4d..41fb0c5b03cbf 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalGeoBoundsTests.java
+++ b/modules/geo/src/test/java/org/opensearch/geo/search/aggregations/metrics/InternalGeoBoundsTests.java
@@ -30,11 +30,18 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.metrics;
+package org.opensearch.geo.search.aggregations.metrics;
 
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.geo.GeoModulePlugin;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.ParsedAggregation;
 import org.opensearch.test.InternalAggregationTestCase;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -44,6 +51,30 @@
 public class InternalGeoBoundsTests extends InternalAggregationTestCase<InternalGeoBounds> {
     static final double GEOHASH_TOLERANCE = 1E-5D;
 
+    /**
+     * Overriding the method so that tests can get the aggregation specs for namedWriteable.
+     *
+     * @return GeoPlugin
+     */
+    @Override
+    protected SearchPlugin registerPlugin() {
+        return new GeoModulePlugin();
+    }
+
+    /**
+     * Overriding with the {@link ParsedGeoBounds} so that it can be parsed. We need to do this as {@link GeoModulePlugin}
+     * is registering this Aggregation.
+     *
+     * @return a List of {@link NamedXContentRegistry.Entry}
+     */
+    @Override
+    protected List<NamedXContentRegistry.Entry> getNamedXContents() {
+        final List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(getDefaultNamedXContents());
+        final ContextParser<Object, Aggregation> parser = (p, c) -> ParsedGeoBounds.fromXContent(p, (String) c);
+        namedXContents.add(new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(GeoBoundsAggregationBuilder.NAME), parser));
+        return namedXContents;
+    }
+
     @Override
     protected InternalGeoBounds createTestInstance(String name, Map<String, Object> metadata) {
         // we occasionally want to test top = Double.NEGATIVE_INFINITY since this triggers empty xContent object
diff --git a/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationBuilders.java b/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationBuilders.java
new file mode 100644
index 0000000000000..c0d7e51047c6b
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationBuilders.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.tests.common;
+
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.InternalGeoHashGrid;
+import org.opensearch.geo.search.aggregations.bucket.geogrid.InternalGeoTileGrid;
+import org.opensearch.geo.search.aggregations.metrics.GeoBounds;
+import org.opensearch.geo.search.aggregations.metrics.GeoBoundsAggregationBuilder;
+
+public class AggregationBuilders {
+    /**
+     * Create a new {@link GeoBounds} aggregation with the given name.
+     */
+    public static GeoBoundsAggregationBuilder geoBounds(String name) {
+        return new GeoBoundsAggregationBuilder(name);
+    }
+
+    /**
+     * Create a new {@link InternalGeoHashGrid} aggregation with the given name.
+     */
+    public static GeoHashGridAggregationBuilder geohashGrid(String name) {
+        return new GeoHashGridAggregationBuilder(name);
+    }
+
+    /**
+     * Create a new {@link InternalGeoTileGrid} aggregation with the given name.
+     */
+    public static GeoTileGridAggregationBuilder geotileGrid(String name) {
+        return new GeoTileGridAggregationBuilder(name);
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationInspectionHelper.java b/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationInspectionHelper.java
new file mode 100644
index 0000000000000..3473cf2d94b76
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/tests/common/AggregationInspectionHelper.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.tests.common;
+
+import org.opensearch.geo.search.aggregations.bucket.geogrid.InternalGeoGrid;
+import org.opensearch.geo.search.aggregations.metrics.InternalGeoBounds;
+
+public class AggregationInspectionHelper {
+
+    public static boolean hasValue(InternalGeoBounds agg) {
+        return (agg.topLeft() == null && agg.bottomRight() == null) == false;
+    }
+
+    public static boolean hasValue(InternalGeoGrid<?> agg) {
+        return agg.getBuckets().stream().anyMatch(bucket -> bucket.getDocCount() > 0);
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGenerator.java b/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGenerator.java
new file mode 100644
index 0000000000000..a3def686b282d
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGenerator.java
@@ -0,0 +1,97 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.tests.common;
+
+import org.opensearch.common.geo.GeoBoundingBox;
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.geo.GeometryTestUtils;
+import org.opensearch.geometry.Rectangle;
+
+import java.util.Random;
+
+/**
+ * Random geo generation utilities for randomized {@code geo_point} type testing
+ * does not depend on jts or spatial4j. Use RandomShapeGenerator to create random OGC compliant shapes.
+ * This is a copy of the file present in the server folder. We need to keep both as there are tests which are
+ * dependent on that file.
+ */
+public class RandomGeoGenerator {
+
+    public static void randomPoint(Random r, double[] pt) {
+        final double[] min = { -180, -90 };
+        final double[] max = { 180, 90 };
+        randomPointIn(r, min[0], min[1], max[0], max[1], pt);
+    }
+
+    public static void randomPointIn(
+        Random r,
+        final double minLon,
+        final double minLat,
+        final double maxLon,
+        final double maxLat,
+        double[] pt
+    ) {
+        assert pt != null && pt.length == 2;
+
+        // normalize min and max
+        double[] min = { normalizeLongitude(minLon), normalizeLatitude(minLat) };
+        double[] max = { normalizeLongitude(maxLon), normalizeLatitude(maxLat) };
+        final double[] tMin = new double[2];
+        final double[] tMax = new double[2];
+        tMin[0] = Math.min(min[0], max[0]);
+        tMax[0] = Math.max(min[0], max[0]);
+        tMin[1] = Math.min(min[1], max[1]);
+        tMax[1] = Math.max(min[1], max[1]);
+
+        pt[0] = tMin[0] + r.nextDouble() * (tMax[0] - tMin[0]);
+        pt[1] = tMin[1] + r.nextDouble() * (tMax[1] - tMin[1]);
+    }
+
+    public static GeoPoint randomPoint(Random r) {
+        return randomPointIn(r, -180, -90, 180, 90);
+    }
+
+    public static GeoPoint randomPointIn(Random r, final double minLon, final double minLat, final double maxLon, final double maxLat) {
+        double[] pt = new double[2];
+        randomPointIn(r, minLon, minLat, maxLon, maxLat, pt);
+        return new GeoPoint(pt[1], pt[0]);
+    }
+
+    /** Puts latitude in range of -90 to 90. */
+    public static double normalizeLatitude(double latitude) {
+        if (latitude >= -90 && latitude <= 90) {
+            return latitude; // common case, and avoids slight double precision shifting
+        }
+        double off = Math.abs((latitude + 90) % 360);
+        return (off <= 180 ? off : 360 - off) - 90;
+    }
+
+    /** Puts longitude in range of -180 to +180. */
+    public static double normalizeLongitude(double longitude) {
+        if (longitude >= -180 && longitude <= 180) {
+            return longitude; // common case, and avoids slight double precision shifting
+        }
+        double off = (longitude + 180) % 360;
+        if (off < 0) {
+            return 180 + off;
+        } else if (off == 0 && longitude > 0) {
+            return 180;
+        } else {
+            return -180 + off;
+        }
+    }
+
+    public static GeoBoundingBox randomBBox() {
+        Rectangle rectangle = GeometryTestUtils.randomRectangle();
+        return new GeoBoundingBox(
+            new GeoPoint(rectangle.getMaxLat(), rectangle.getMinLon()),
+            new GeoPoint(rectangle.getMinLat(), rectangle.getMaxLon())
+        );
+    }
+}
diff --git a/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGeometryGenerator.java b/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGeometryGenerator.java
new file mode 100644
index 0000000000000..45a72c7103ae9
--- /dev/null
+++ b/modules/geo/src/test/java/org/opensearch/geo/tests/common/RandomGeoGeometryGenerator.java
@@ -0,0 +1,260 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.geo.tests.common;
+
+import org.opensearch.geo.algorithm.PolygonGenerator;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.GeometryCollection;
+import org.opensearch.geometry.Line;
+import org.opensearch.geometry.LinearRing;
+import org.opensearch.geometry.MultiLine;
+import org.opensearch.geometry.MultiPoint;
+import org.opensearch.geometry.MultiPolygon;
+import org.opensearch.geometry.Point;
+import org.opensearch.geometry.Polygon;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.geometry.ShapeType;
+import org.opensearch.index.mapper.GeoShapeIndexer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Assert;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.Random;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * Random geo generation utilities for randomized geo_shape type testing.
+ */
+public class RandomGeoGeometryGenerator {
+    // Just picking a number 10 to be the max edges of a polygon. Don't want to make too large which can impact
+    // debugging.
+    private static final int MAX_VERTEXES = 10;
+    private static final int MAX_MULTIPLE_GEOMETRIES = 10;
+
+    private static final Predicate<ShapeType> NOT_SUPPORTED_SHAPES = shapeType -> shapeType != ShapeType.CIRCLE
+        && shapeType != ShapeType.LINEARRING;
+
+    /**
+     * Creating list of only supported geometries defined here: {@link GeoShapeIndexer#prepareForIndexing(Geometry)}
+     */
+    private static final List<ShapeType> SUPPORTED_SHAPE_TYPES = Arrays.stream(ShapeType.values())
+        .filter(NOT_SUPPORTED_SHAPES)
+        .collect(Collectors.toList());
+
+    /**
+     * Returns a random Geometry. It makes sure that only that geometry is returned which is supported by OpenSearch
+     * while indexing. Check {@link GeoShapeIndexer#prepareForIndexing(Geometry)}
+     *
+     * @return {@link Geometry}
+     */
+    public static Geometry randomGeometry(final Random r) {
+        final ShapeType randomShapeType = SUPPORTED_SHAPE_TYPES.get(
+            OpenSearchTestCase.randomIntBetween(0, SUPPORTED_SHAPE_TYPES.size() - 1)
+        );
+        switch (randomShapeType) {
+            case POINT:
+                return randomPoint(r);
+            case MULTIPOINT:
+                return randomMultiPoint(r);
+            case POLYGON:
+                return randomPolygon(r);
+            case LINESTRING:
+                return randomLine(r);
+            case MULTIPOLYGON:
+                return randomMultiPolygon(r);
+            case GEOMETRYCOLLECTION:
+                return randomGeometryCollection(r);
+            case MULTILINESTRING:
+                return randomMultiLine(r);
+            case ENVELOPE:
+                return randomRectangle(r);
+            default:
+                Assert.fail(String.format(Locale.ROOT, "Cannot create a geometry of type %s ", randomShapeType));
+        }
+        return null;
+    }
+
+    /**
+     * Generate a random point on the Earth Surface.
+     *
+     * @param r {@link Random}
+     * @return {@link Point}
+     */
+    public static Point randomPoint(final Random r) {
+        double[] pt = getLonAndLatitude(r);
+        return new Point(pt[0], pt[1]);
+    }
+
+    /**
+     * Generate a random polygon on earth surface.
+     *
+     * @param r {@link Random}
+     * @return {@link Polygon}
+     */
+    public static Polygon randomPolygon(final Random r) {
+        final int vertexCount = OpenSearchTestCase.randomIntBetween(3, MAX_VERTEXES);
+        return randomPolygonWithFixedVertexCount(r, vertexCount);
+    }
+
+    /**
+     * Generate a random line on the earth Surface.
+     *
+     * @param r {@link Random}
+     * @return {@link Line}
+     */
+    public static Line randomLine(final Random r) {
+        final double[] pt1 = getLonAndLatitude(r);
+        final double[] pt2 = getLonAndLatitude(r);
+        final double[] x = { pt1[0], pt2[0] };
+        final double[] y = { pt1[1], pt2[1] };
+        return new Line(x, y);
+    }
+
+    /**
+     * Returns an object of {@link MultiPoint} denoting a list of points on earth surface.
+     * @param r {@link Random}
+     * @return {@link MultiPoint}
+     */
+    public static MultiPoint randomMultiPoint(final Random r) {
+        int multiplePoints = OpenSearchTestCase.randomIntBetween(1, MAX_MULTIPLE_GEOMETRIES);
+        final List<Point> pointsList = new ArrayList<>();
+        IntStream.range(0, multiplePoints).forEach(i -> pointsList.add(randomPoint(r)));
+        return new MultiPoint(pointsList);
+    }
+
+    /**
+     * Returns an object of {@link MultiPolygon} denoting various polygons on earth surface.
+     *
+     * @param r {@link Random}
+     * @return {@link MultiPolygon}
+     */
+    public static MultiPolygon randomMultiPolygon(final Random r) {
+        int multiplePolygons = OpenSearchTestCase.randomIntBetween(1, MAX_MULTIPLE_GEOMETRIES);
+        final List<Polygon> polygonList = new ArrayList<>();
+        IntStream.range(0, multiplePolygons).forEach(i -> polygonList.add(randomPolygon(r)));
+        return new MultiPolygon(polygonList);
+    }
+
+    /**
+     * Returns an object of {@link GeometryCollection} having various shapes on earth surface.
+     *
+     * @param r {@link Random}
+     * @return {@link GeometryCollection}
+     */
+    public static GeometryCollection<?> randomGeometryCollection(final Random r) {
+        final List<Geometry> geometries = new ArrayList<>();
+        geometries.addAll(randomMultiPoint(r).getAll());
+        geometries.addAll(randomMultiPolygon(r).getAll());
+        geometries.addAll(randomMultiLine(r).getAll());
+        geometries.add(randomPoint(r));
+        geometries.add(randomLine(r));
+        geometries.add(randomPolygon(r));
+        geometries.add(randomRectangle(r));
+        return new GeometryCollection<>(geometries);
+    }
+
+    /**
+     * Returns a {@link MultiLine} object containing multiple lines on earth surface.
+     *
+     * @param r {@link Random}
+     * @return {@link MultiLine}
+     */
+    public static MultiLine randomMultiLine(Random r) {
+        int multiLines = OpenSearchTestCase.randomIntBetween(1, MAX_MULTIPLE_GEOMETRIES);
+        final List<Line> linesList = new ArrayList<>();
+        IntStream.range(0, multiLines).forEach(i -> linesList.add(randomLine(r)));
+        return new MultiLine(linesList);
+    }
+
+    /**
+     * Returns a random {@link Rectangle} created on earth surface.
+     *
+     * @param r {@link Random}
+     * @return {@link Rectangle}
+     */
+    public static Rectangle randomRectangle(final Random r) {
+        final Polygon polygon = randomPolygonWithFixedVertexCount(r, 4);
+        double minX = Double.POSITIVE_INFINITY, maxX = Double.NEGATIVE_INFINITY, maxY = Double.NEGATIVE_INFINITY, minY =
+            Double.POSITIVE_INFINITY;
+        for (int i = 0; i < polygon.getPolygon().length(); i++) {
+            double x = polygon.getPolygon().getX()[i];
+            double y = polygon.getPolygon().getY()[i];
+
+            minX = Math.min(minX, x);
+            minY = Math.min(minY, y);
+            maxX = Math.max(maxX, x);
+            maxY = Math.max(maxY, y);
+        }
+        return new Rectangle(minX, maxX, maxY, minY);
+    }
+
+    /**
+     * Generates a {@link Rectangle} of a specific radius. The generated rectangle can cross the international date line.
+     *
+     * @param r {@link Random}
+     * @param radius double
+     * @return {@link Rectangle}
+     */
+    public static Rectangle randomRectangle(final Random r, double radius) {
+        final double[] centre = new double[2];
+        RandomGeoGenerator.randomPointIn(r, -180, -(90 - radius), 180, 90 - radius, centre);
+        final double centreX = centre[0];
+        final double centreY = centre[1];
+        return new Rectangle(
+            RandomGeoGenerator.normalizeLongitude(centreX - radius),
+            RandomGeoGenerator.normalizeLongitude(centreX + radius),
+            centreY + radius,
+            centreY - radius
+        );
+    }
+
+    /**
+     * Returns a double array where pt[0] : longitude and pt[1] : latitude
+     *
+     * @param r {@link Random}
+     * @return double[]
+     */
+    private static double[] getLonAndLatitude(final Random r) {
+        double[] pt = new double[2];
+        RandomGeoGenerator.randomPoint(r, pt);
+        return pt;
+    }
+
+    private static Polygon randomPolygonWithFixedVertexCount(final Random r, final int vertexCount) {
+        final List<Double> xPool = new ArrayList<>(vertexCount);
+        final List<Double> yPool = new ArrayList<>(vertexCount);
+        IntStream.range(0, vertexCount).forEach(iterator -> {
+            double[] pt = getLonAndLatitude(r);
+            xPool.add(pt[0]);
+            yPool.add(pt[1]);
+        });
+        final List<double[]> pointsList = PolygonGenerator.generatePolygon(xPool, yPool, r);
+        // Checking the list
+        assert vertexCount == pointsList.get(0).length;
+        assert vertexCount == pointsList.get(1).length;
+        // Create the linearRing, as we need to close the polygon hence increasing vertexes count by 1
+        final double[] x = new double[vertexCount + 1];
+        final double[] y = new double[vertexCount + 1];
+        IntStream.range(0, vertexCount).forEach(iterator -> {
+            x[iterator] = pointsList.get(0)[iterator];
+            y[iterator] = pointsList.get(1)[iterator];
+        });
+        // making sure to close the polygon
+        x[vertexCount] = x[0];
+        y[vertexCount] = y[0];
+        final LinearRing linearRing = new LinearRing(x, y);
+        return new Polygon(linearRing);
+    }
+
+}
diff --git a/modules/geo/src/yamlRestTest/java/org/opensearch/geo/GeoClientYamlTestSuiteIT.java b/modules/geo/src/yamlRestTest/java/org/opensearch/geo/GeoClientYamlTestSuiteIT.java
index 22604cff0fcf1..1f734b156689d 100644
--- a/modules/geo/src/yamlRestTest/java/org/opensearch/geo/GeoClientYamlTestSuiteIT.java
+++ b/modules/geo/src/yamlRestTest/java/org/opensearch/geo/GeoClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/230_composite.yml b/modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/230_composite.yml
new file mode 100644
index 0000000000000..211f3c3f46b88
--- /dev/null
+++ b/modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/230_composite.yml
@@ -0,0 +1,168 @@
+---
+setup:
+  - do:
+      indices.create:
+        index: test
+        body:
+          mappings:
+            properties:
+              date:
+                type: date
+              keyword:
+                type: keyword
+              long:
+                type: long
+              geo_point:
+                type: geo_point
+              nested:
+                type: nested
+                properties:
+                  nested_long:
+                    type: long
+
+  - do:
+      indices.create:
+        index: other
+        body:
+          mappings:
+            properties:
+              date:
+                type: date
+              long:
+                type: long
+              nested:
+                type: nested
+                properties:
+                  nested_long:
+                    type: long
+
+  - do:
+      index:
+        index: test
+        id:    1
+        body:  { "keyword": "foo", "long": [10, 20], "geo_point": "37.2343,-115.8067", "nested": [{"nested_long": 10}, {"nested_long": 20}] }
+
+  - do:
+      index:
+        index: test
+        id:    2
+        body:  { "keyword": ["foo", "bar"], "geo_point": "41.12,-71.34" }
+
+  - do:
+      index:
+        index: test
+        id:    3
+        body:  { "keyword": "bar", "long": [100, 0], "geo_point": "90.0,0.0", "nested": [{"nested_long": 10}, {"nested_long": 0}] }
+
+  - do:
+      index:
+        index: test
+        id:    4
+        body:  { "keyword": "bar", "long": [1000, 0], "geo_point": "41.12,-71.34", "nested": [{"nested_long": 1000}, {"nested_long": 20}] }
+
+  - do:
+      index:
+        index: test
+        id:    5
+        body:  { "date": "2017-10-20T03:08:45" }
+
+  - do:
+      index:
+        index: test
+        id:    6
+        body:  { "date": "2017-10-21T07:00:00" }
+
+  - do:
+      index:
+        index: other
+        id:    0
+        body:  { "date": "2017-10-20T03:08:45" }
+
+  - do:
+      indices.refresh:
+        index: [test, other]
+---
+"Simple Composite aggregation with GeoTile grid":
+  - skip:
+      version: " - 7.4.99"
+      reason: geotile_grid is not supported until 7.5.0
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          aggregations:
+            test:
+              composite:
+                sources: [
+                  "geo": {
+                    "geotile_grid": {
+                      "field": "geo_point",
+                      "precision": 12
+                    }
+                  },
+                  {
+                    "kw": {
+                      "terms": {
+                        "field": "keyword"
+                      }
+                    }
+                  }
+                ]
+
+  - match: {hits.total: 6}
+  - length: { aggregations.test.buckets: 4 }
+  - match: { aggregations.test.buckets.0.key.geo: "12/730/1590" }
+  - match: { aggregations.test.buckets.0.key.kw: "foo" }
+  - match: { aggregations.test.buckets.0.doc_count: 1 }
+  - match: { aggregations.test.buckets.1.key.geo: "12/1236/1533" }
+  - match: { aggregations.test.buckets.1.key.kw: "bar" }
+  - match: { aggregations.test.buckets.1.doc_count: 2 }
+  - match: { aggregations.test.buckets.2.key.geo: "12/1236/1533" }
+  - match: { aggregations.test.buckets.2.key.kw: "foo" }
+  - match: { aggregations.test.buckets.2.doc_count: 1 }
+  - match: { aggregations.test.buckets.3.key.geo: "12/2048/0" }
+  - match: { aggregations.test.buckets.3.key.kw: "bar" }
+  - match: { aggregations.test.buckets.3.doc_count: 1 }
+
+---
+"Simple Composite aggregation with geotile grid add aggregate after":
+  - skip:
+      version: " - 7.4.99"
+      reason: geotile_grid is not supported until 7.5.0
+  - do:
+      search:
+        index: test
+        body:
+          aggregations:
+            test:
+              composite:
+                sources: [
+                  "geo": {
+                    "geotile_grid": {
+                      "field": "geo_point",
+                      "precision": 12
+                    }
+                  },
+                  {
+                    "kw": {
+                      "terms": {
+                        "field": "keyword"
+                      }
+                    }
+                  }
+                ]
+                after: { "geo": "12/730/1590", "kw": "foo" }
+
+  - match: { hits.total.value: 6 }
+  - match: { hits.total.relation: "eq" }
+  - length: { aggregations.test.buckets: 3 }
+  - match: { aggregations.test.buckets.0.key.geo: "12/1236/1533" }
+  - match: { aggregations.test.buckets.0.key.kw: "bar" }
+  - match: { aggregations.test.buckets.0.doc_count: 2 }
+  - match: { aggregations.test.buckets.1.key.geo: "12/1236/1533" }
+  - match: { aggregations.test.buckets.1.key.kw: "foo" }
+  - match: { aggregations.test.buckets.1.doc_count: 1 }
+  - match: { aggregations.test.buckets.2.key.geo: "12/2048/0" }
+  - match: { aggregations.test.buckets.2.key.kw: "bar" }
+  - match: { aggregations.test.buckets.2.doc_count: 1 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/280_geohash_grid.yml b/modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/280_geohash_grid.yml
similarity index 100%
rename from rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/280_geohash_grid.yml
rename to modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/280_geohash_grid.yml
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/290_geotile_grid.yml b/modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/290_geotile_grid.yml
similarity index 100%
rename from rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/290_geotile_grid.yml
rename to modules/geo/src/yamlRestTest/resources/rest-api-spec/test/geo_shape/290_geotile_grid.yml
diff --git a/modules/ingest-common/src/internalClusterTest/java/org/opensearch/ingest/common/IngestRestartIT.java b/modules/ingest-common/src/internalClusterTest/java/org/opensearch/ingest/common/IngestRestartIT.java
index aeaa7246f33b8..c5f9c6ce24b34 100644
--- a/modules/ingest-common/src/internalClusterTest/java/org/opensearch/ingest/common/IngestRestartIT.java
+++ b/modules/ingest-common/src/internalClusterTest/java/org/opensearch/ingest/common/IngestRestartIT.java
@@ -33,16 +33,16 @@
 
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.ingest.IngestStats;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.MockScriptPlugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -86,7 +86,7 @@ protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
 
     public void testFailureInConditionalProcessor() {
         internalCluster().ensureAtLeastNumDataNodes(1);
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String pipelineId = "foo";
         client().admin()
             .cluster()
@@ -108,7 +108,7 @@ public void testFailureInConditionalProcessor() {
                         + "  ]\n"
                         + "}"
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
@@ -132,7 +132,7 @@ public void testFailureInConditionalProcessor() {
         for (int k = 0; k < nodeCount; k++) {
             List<IngestStats.ProcessorStat> stats = r.getNodes().get(k).getIngestStats().getProcessorStats().get(pipelineId);
             for (IngestStats.ProcessorStat st : stats) {
-                assertThat(st.getStats().getIngestCurrent(), greaterThanOrEqualTo(0L));
+                assertThat(st.getStats().getCurrent(), greaterThanOrEqualTo(0L));
             }
         }
     }
@@ -160,13 +160,13 @@ public void testScriptDisabled() throws Exception {
             equalTo(id)
         );
 
-        client().admin().cluster().preparePutPipeline(pipelineIdWithScript, pipelineWithScript, XContentType.JSON).get();
-        client().admin().cluster().preparePutPipeline(pipelineIdWithoutScript, pipelineWithoutScript, XContentType.JSON).get();
+        client().admin().cluster().preparePutPipeline(pipelineIdWithScript, pipelineWithScript, MediaTypeRegistry.JSON).get();
+        client().admin().cluster().preparePutPipeline(pipelineIdWithoutScript, pipelineWithoutScript, MediaTypeRegistry.JSON).get();
 
         checkPipelineExists.accept(pipelineIdWithScript);
         checkPipelineExists.accept(pipelineIdWithoutScript);
 
-        internalCluster().restartNode(internalCluster().getMasterName(), new InternalTestCluster.RestartCallback() {
+        internalCluster().restartNode(internalCluster().getClusterManagerName(), new InternalTestCluster.RestartCallback() {
 
             @Override
             public Settings onNodeStopped(String nodeName) {
@@ -225,7 +225,7 @@ public void testPipelineWithScriptProcessorThatHasStoredScript() throws Exceptio
             .setId("1")
             .setContent(
                 new BytesArray("{\"script\": {\"lang\": \"" + MockScriptEngine.NAME + "\", \"source\": \"my_script\"} }"),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
         BytesReference pipeline = new BytesArray(
@@ -236,7 +236,7 @@ public void testPipelineWithScriptProcessorThatHasStoredScript() throws Exceptio
                 + "  ]\n"
                 + "}"
         );
-        client().admin().cluster().preparePutPipeline("_id", pipeline, XContentType.JSON).get();
+        client().admin().cluster().preparePutPipeline("_id", pipeline, MediaTypeRegistry.JSON).get();
 
         client().prepareIndex("index")
             .setId("1")
@@ -277,7 +277,7 @@ public void testWithDedicatedIngestNode() throws Exception {
         BytesReference pipeline = new BytesArray(
             "{\n" + "  \"processors\" : [\n" + "      {\"set\" : {\"field\": \"y\", \"value\": 0}}\n" + "  ]\n" + "}"
         );
-        client().admin().cluster().preparePutPipeline("_id", pipeline, XContentType.JSON).get();
+        client().admin().cluster().preparePutPipeline("_id", pipeline, MediaTypeRegistry.JSON).get();
 
         client().prepareIndex("index")
             .setId("1")
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/BytesProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/BytesProcessor.java
index 3bd1137975800..b76fe41c8e67d 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/BytesProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/BytesProcessor.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.ingest.common;
 
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.Map;
 
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/GrokProcessorGetAction.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/GrokProcessorGetAction.java
index bb587350f4256..06709de73be01 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/GrokProcessorGetAction.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/GrokProcessorGetAction.java
@@ -32,19 +32,19 @@
 package org.opensearch.ingest.common;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.grok.Grok;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/IngestCommonPlugin.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/IngestCommonPlugin.java
index 969f77aa85152..672760b284004 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/IngestCommonPlugin.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/IngestCommonPlugin.java
@@ -33,7 +33,6 @@
 package org.opensearch.ingest.common;
 
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.settings.ClusterSettings;
@@ -42,6 +41,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.grok.Grok;
 import org.opensearch.grok.MatcherWatchdog;
 import org.opensearch.ingest.DropProcessor;
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/JsonProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/JsonProcessor.java
index a2b740291d04e..6de3e236ee40c 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/JsonProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/JsonProcessor.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.ingest.common;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java
index 5da3b6bea7bc2..93a35eef4d396 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.ingest.common;
 
+import org.opensearch.core.common.Strings;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
@@ -66,16 +67,20 @@ public List<TemplateScript.Factory> getFields() {
 
     @Override
     public IngestDocument execute(IngestDocument document) {
-        if (ignoreMissing) {
-            fields.forEach(field -> {
-                String path = document.renderTemplate(field);
-                if (document.hasField(path)) {
-                    document.removeField(path);
+        fields.forEach(field -> {
+            String path = document.renderTemplate(field);
+            final boolean fieldPathIsNullOrEmpty = Strings.isNullOrEmpty(path);
+            if (fieldPathIsNullOrEmpty || document.hasField(path) == false) {
+                if (ignoreMissing) {
+                    return;
+                } else if (fieldPathIsNullOrEmpty) {
+                    throw new IllegalArgumentException("field path cannot be null nor empty");
+                } else {
+                    throw new IllegalArgumentException("field [" + path + "] doesn't exist");
                 }
-            });
-        } else {
-            fields.forEach(document::removeField);
-        }
+            }
+            document.removeField(path);
+        });
         return document;
     }
 
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RenameProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RenameProcessor.java
index af356eb10d79c..7564bbdf95f45 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RenameProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/RenameProcessor.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.ingest.common;
 
+import org.opensearch.core.common.Strings;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
@@ -80,9 +81,12 @@ boolean isIgnoreMissing() {
     @Override
     public IngestDocument execute(IngestDocument document) {
         String path = document.renderTemplate(field);
-        if (document.hasField(path, true) == false) {
+        final boolean fieldPathIsNullOrEmpty = Strings.isNullOrEmpty(path);
+        if (fieldPathIsNullOrEmpty || document.hasField(path, true) == false) {
             if (ignoreMissing) {
                 return document;
+            } else if (fieldPathIsNullOrEmpty) {
+                throw new IllegalArgumentException("field path cannot be null nor empty");
             } else {
                 throw new IllegalArgumentException("field [" + path + "] doesn't exist");
             }
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/ScriptProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/ScriptProcessor.java
index f2568826fa484..cc8889af27621 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/ScriptProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/ScriptProcessor.java
@@ -33,19 +33,17 @@
 package org.opensearch.ingest.common;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Processor;
-import org.opensearch.script.DynamicMap;
 import org.opensearch.script.IngestScript;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptException;
@@ -55,7 +53,6 @@
 import java.io.InputStream;
 import java.util.Arrays;
 import java.util.Map;
-import java.util.function.Function;
 
 import static org.opensearch.ingest.ConfigurationUtils.newConfigurationException;
 
@@ -64,12 +61,6 @@
  */
 public final class ScriptProcessor extends AbstractProcessor {
 
-    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("_type", value -> {
-        deprecationLogger.deprecate("script_processor", "[types removal] Looking up doc types [_type] in scripts is deprecated.");
-        return value;
-    });
-
     public static final String TYPE = "script";
 
     private final Script script;
@@ -111,7 +102,7 @@ public IngestDocument execute(IngestDocument document) {
         } else {
             ingestScript = precompiledIngestScript;
         }
-        ingestScript.execute(new DynamicMap(document.getSourceAndMetadata(), PARAMS_FUNCTIONS));
+        ingestScript.execute(document.getSourceAndMetadata());
         CollectionUtils.ensureNoSelfReferences(document.getSourceAndMetadata(), "ingest script");
         return document;
     }
@@ -146,7 +137,7 @@ public ScriptProcessor create(
             try (
                 XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(config);
                 InputStream stream = BytesReference.bytes(builder).streamInput();
-                XContentParser parser = XContentType.JSON.xContent()
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
             ) {
                 Script script = Script.parse(parser);
diff --git a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/URLDecodeProcessor.java b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/URLDecodeProcessor.java
index bf80c5b064703..bb236f957a587 100644
--- a/modules/ingest-common/src/main/java/org/opensearch/ingest/common/URLDecodeProcessor.java
+++ b/modules/ingest-common/src/main/java/org/opensearch/ingest/common/URLDecodeProcessor.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.ingest.common;
 
-import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
 /**
@@ -48,11 +48,7 @@ public final class URLDecodeProcessor extends AbstractStringProcessor<String> {
     }
 
     public static String apply(String value) {
-        try {
-            return URLDecoder.decode(value, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-            throw new IllegalArgumentException("Could not URL-decode value.", e);
-        }
+        return URLDecoder.decode(value, StandardCharsets.UTF_8);
     }
 
     @Override
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/AppendProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/AppendProcessorTests.java
index 7caa63792f347..1cb1ad7e408f6 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/AppendProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/AppendProcessorTests.java
@@ -203,7 +203,7 @@ public void testAppendingUniqueValueToScalar() throws Exception {
         appendProcessor.execute(ingestDocument);
         List<?> list = ingestDocument.getFieldValue(field, List.class);
         assertThat(list.size(), equalTo(2));
-        assertThat(list, equalTo(org.opensearch.common.collect.List.of(originalValue, newValue)));
+        assertThat(list, equalTo(List.of(originalValue, newValue)));
     }
 
     public void testAppendingToListWithDuplicatesDisallowed() throws Exception {
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/BytesProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/BytesProcessorTests.java
index bbd9ff4c8b912..ce8c182b60a61 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/BytesProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/BytesProcessorTests.java
@@ -33,15 +33,14 @@
 package org.opensearch.ingest.common;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Processor;
 import org.opensearch.ingest.RandomDocumentPicks;
 import org.hamcrest.CoreMatchers;
 
-import static org.hamcrest.Matchers.equalTo;
-
 public class BytesProcessorTests extends AbstractStringProcessorTestCase<Long> {
 
     private String modifiedInput;
@@ -101,14 +100,16 @@ public void testMissingUnits() {
         assertThat(exception.getMessage(), CoreMatchers.containsString("unit is missing or unrecognized"));
     }
 
-    public void testFractional() throws Exception {
+    public void testFractional() {
         IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random());
         String fieldName = RandomDocumentPicks.addRandomField(random(), ingestDocument, "1.1kb");
         Processor processor = newProcessor(fieldName, randomBoolean(), fieldName);
-        processor.execute(ingestDocument);
-        assertThat(ingestDocument.getFieldValue(fieldName, expectedResultType()), equalTo(1126L));
-        assertWarnings(
-            "Fractional bytes values are deprecated. Use non-fractional bytes values instead: [1.1kb] found for setting " + "[Ingest Field]"
+        OpenSearchParseException e = expectThrows(OpenSearchParseException.class, () -> processor.execute(ingestDocument));
+        assertThat(
+            e.getMessage(),
+            CoreMatchers.containsString(
+                "Fractional bytes values have been deprecated since Legacy 6.2. " + "Use non-fractional bytes values instead:"
+            )
         );
     }
 }
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ConvertProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ConvertProcessorTests.java
index 6eed29e330f2c..0ba0a39261d00 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ConvertProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ConvertProcessorTests.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.ingest.common;
 
+import org.opensearch.ingest.IngestDocument;
+import org.opensearch.ingest.Processor;
+import org.opensearch.ingest.RandomDocumentPicks;
+import org.opensearch.test.OpenSearchTestCase;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -39,11 +44,6 @@
 import java.util.Locale;
 import java.util.Map;
 
-import org.opensearch.ingest.IngestDocument;
-import org.opensearch.ingest.Processor;
-import org.opensearch.ingest.RandomDocumentPicks;
-import org.opensearch.test.OpenSearchTestCase;
-
 import static org.opensearch.ingest.IngestDocumentMatcher.assertIngestDocument;
 import static org.opensearch.ingest.common.ConvertProcessor.Type;
 import static org.hamcrest.Matchers.containsString;
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/CsvProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/CsvProcessorTests.java
index 1359750dc16ea..650104ac3e9a0 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/CsvProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/CsvProcessorTests.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/DateFormatTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/DateFormatTests.java
index 951b93deb6e8b..04900fe6f7496 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/DateFormatTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/DateFormatTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.ingest.common;
 
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateUtils;
 import org.opensearch.test.OpenSearchTestCase;
@@ -96,10 +95,6 @@ public void testParseJavaDefaultYear() {
     }
 
     public void testParseWeekBased() {
-        assumeFalse(
-            "won't work in jdk8 " + "because SPI mechanism is not looking at classpath - needs ISOCalendarDataProvider in jre's ext/libs",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
         String format = randomFrom("YYYY-ww");
         ZoneId timezone = DateUtils.of("Europe/Amsterdam");
         Function<String, ZonedDateTime> javaFunction = DateFormat.Java.getFunction(format, timezone, Locale.ROOT);
@@ -108,10 +103,6 @@ public void testParseWeekBased() {
     }
 
     public void testParseWeekBasedWithLocale() {
-        assumeFalse(
-            "won't work in jdk8 " + "because SPI mechanism is not looking at classpath - needs ISOCalendarDataProvider in jre's ext/libs",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
         String format = randomFrom("YYYY-ww");
         ZoneId timezone = DateUtils.of("Europe/Amsterdam");
         Function<String, ZonedDateTime> javaFunction = DateFormat.Java.getFunction(format, timezone, Locale.US);
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ForEachProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ForEachProcessorTests.java
index 8db3cefc3a6fd..241945e58fa06 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ForEachProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ForEachProcessorTests.java
@@ -127,7 +127,6 @@ public void testMetadataAvailable() throws Exception {
 
         TestProcessor innerProcessor = new TestProcessor(id -> {
             id.setFieldValue("_ingest._value.index", id.getSourceAndMetadata().get("_index"));
-            id.setFieldValue("_ingest._value.type", id.getSourceAndMetadata().get("_type"));
             id.setFieldValue("_ingest._value.id", id.getSourceAndMetadata().get("_id"));
         });
         ForEachProcessor processor = new ForEachProcessor("_tag", null, "values", innerProcessor, false);
@@ -227,12 +226,8 @@ public void testModifyFieldsOutsideArray() throws Exception {
             "values",
             new CompoundProcessor(
                 false,
-                org.opensearch.common.collect.List.of(
-                    new UppercaseProcessor("_tag_upper", null, "_ingest._value", false, "_ingest._value")
-                ),
-                org.opensearch.common.collect.List.of(
-                    new AppendProcessor("_tag", null, template, (model) -> (Collections.singletonList("added")), true)
-                )
+                List.of(new UppercaseProcessor("_tag_upper", null, "_ingest._value", false, "_ingest._value")),
+                List.of(new AppendProcessor("_tag", null, template, (model) -> (Collections.singletonList("added")), true))
             ),
             false
         );
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/GrokProcessorGetActionTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/GrokProcessorGetActionTests.java
index 5ccf85dd53f0e..f8c760d48920f 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/GrokProcessorGetActionTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/GrokProcessorGetActionTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.ingest.common;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.TransportService;
 
@@ -57,7 +57,7 @@
 import static org.mockito.Mockito.mock;
 
 public class GrokProcessorGetActionTests extends OpenSearchTestCase {
-    private static final Map<String, String> TEST_PATTERNS = org.opensearch.common.collect.Map.of("PATTERN2", "foo2", "PATTERN1", "foo1");
+    private static final Map<String, String> TEST_PATTERNS = Map.of("PATTERN2", "foo2", "PATTERN1", "foo1");
 
     public void testRequest() throws Exception {
         GrokProcessorGetAction.Request request = new GrokProcessorGetAction.Request(false);
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/JsonProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/JsonProcessorTests.java
index 9aad2f9c7edd1..bde5dcd90e951 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/JsonProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/JsonProcessorTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.ingest.common;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.test.OpenSearchTestCase;
@@ -61,7 +61,7 @@ public void testExecute() throws Exception {
 
         Map<String, Object> randomJsonMap = RandomDocumentPicks.randomSource(random());
         XContentBuilder builder = JsonXContent.contentBuilder().map(randomJsonMap);
-        String randomJson = XContentHelper.convertToJson(BytesReference.bytes(builder), false, XContentType.JSON);
+        String randomJson = XContentHelper.convertToJson(BytesReference.bytes(builder), false, MediaTypeRegistry.JSON);
         document.put(randomField, randomJson);
 
         IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random(), document);
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RemoveProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RemoveProcessorTests.java
index cf65236157111..8f729c6a39bbd 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RemoveProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RemoveProcessorTests.java
@@ -42,7 +42,6 @@
 import java.util.HashMap;
 import java.util.Map;
 
-import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
 public class RemoveProcessorTests extends OpenSearchTestCase {
@@ -67,12 +66,44 @@ public void testRemoveNonExistingField() throws Exception {
         config.put("field", fieldName);
         String processorTag = randomAlphaOfLength(10);
         Processor processor = new RemoveProcessor.Factory(TestTemplateService.instance()).create(null, processorTag, null, config);
-        try {
-            processor.execute(ingestDocument);
-            fail("remove field should have failed");
-        } catch (IllegalArgumentException e) {
-            assertThat(e.getMessage(), containsString("not present as part of path [" + fieldName + "]"));
-        }
+        assertThrows(
+            "field [" + fieldName + "] doesn't exist",
+            IllegalArgumentException.class,
+            () -> { processor.execute(ingestDocument); }
+        );
+
+        Map<String, Object> configWithEmptyField = new HashMap<>();
+        configWithEmptyField.put("field", "");
+        processorTag = randomAlphaOfLength(10);
+        Processor removeProcessorWithEmptyField = new RemoveProcessor.Factory(TestTemplateService.instance()).create(
+            null,
+            processorTag,
+            null,
+            configWithEmptyField
+        );
+        assertThrows(
+            "field path cannot be null nor empty",
+            IllegalArgumentException.class,
+            () -> removeProcessorWithEmptyField.execute(ingestDocument)
+        );
+    }
+
+    public void testRemoveEmptyField() throws Exception {
+        IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random(), new HashMap<>());
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", "");
+        String processorTag = randomAlphaOfLength(10);
+        Processor removeProcessorWithEmptyField = new RemoveProcessor.Factory(TestTemplateService.instance()).create(
+            null,
+            processorTag,
+            null,
+            config
+        );
+        assertThrows(
+            "field path cannot be null nor empty",
+            IllegalArgumentException.class,
+            () -> removeProcessorWithEmptyField.execute(ingestDocument)
+        );
     }
 
     public void testIgnoreMissing() throws Exception {
@@ -84,5 +115,13 @@ public void testIgnoreMissing() throws Exception {
         String processorTag = randomAlphaOfLength(10);
         Processor processor = new RemoveProcessor.Factory(TestTemplateService.instance()).create(null, processorTag, null, config);
         processor.execute(ingestDocument);
+
+        // when using template snippet, the resolved field path maybe empty
+        Map<String, Object> configWithEmptyField = new HashMap<>();
+        configWithEmptyField.put("field", "");
+        configWithEmptyField.put("ignore_missing", true);
+        processorTag = randomAlphaOfLength(10);
+        processor = new RemoveProcessor.Factory(TestTemplateService.instance()).create(null, processorTag, null, configWithEmptyField);
+        processor.execute(ingestDocument);
     }
 }
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RenameProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RenameProcessorTests.java
index fc95693024cb0..a600464371af8 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RenameProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/RenameProcessorTests.java
@@ -112,6 +112,15 @@ public void testRenameNonExistingField() throws Exception {
         } catch (IllegalArgumentException e) {
             assertThat(e.getMessage(), equalTo("field [" + fieldName + "] doesn't exist"));
         }
+
+        // when using template snippet, the resolved field path maybe empty
+        processor = createRenameProcessor("", RandomDocumentPicks.randomFieldName(random()), false);
+        try {
+            processor.execute(ingestDocument);
+            fail("processor execute should have failed");
+        } catch (IllegalArgumentException e) {
+            assertThat(e.getMessage(), equalTo("field path cannot be null nor empty"));
+        }
     }
 
     public void testRenameNonExistingFieldWithIgnoreMissing() throws Exception {
@@ -121,6 +130,11 @@ public void testRenameNonExistingFieldWithIgnoreMissing() throws Exception {
         Processor processor = createRenameProcessor(fieldName, RandomDocumentPicks.randomFieldName(random()), true);
         processor.execute(ingestDocument);
         assertIngestDocument(originalIngestDocument, ingestDocument);
+
+        // when using template snippet, the resolved field path maybe empty
+        processor = createRenameProcessor("", RandomDocumentPicks.randomFieldName(random()), true);
+        processor.execute(ingestDocument);
+        assertIngestDocument(originalIngestDocument, ingestDocument);
     }
 
     public void testRenameNewFieldAlreadyExists() throws Exception {
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorFactoryTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorFactoryTests.java
index e5d2334f75ac9..35b56c2677134 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorFactoryTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorFactoryTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParseException;
 import org.opensearch.script.IngestScript;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorTests.java
index 1aa4898441598..96d9be75c4ab7 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/ScriptProcessorTests.java
@@ -105,24 +105,4 @@ private void assertIngestDocument(IngestDocument ingestDocument) {
         int bytesTotal = ingestDocument.getFieldValue("bytes_in", Integer.class) + ingestDocument.getFieldValue("bytes_out", Integer.class);
         assertThat(ingestDocument.getSourceAndMetadata().get("bytes_total"), is(bytesTotal));
     }
-
-    public void testTypeDeprecation() throws Exception {
-        String scriptName = "script";
-        ScriptService scriptService = new ScriptService(
-            Settings.builder().build(),
-            Collections.singletonMap(
-                Script.DEFAULT_SCRIPT_LANG,
-                new MockScriptEngine(Script.DEFAULT_SCRIPT_LANG, Collections.singletonMap(scriptName, ctx -> {
-                    ctx.get("_type");
-                    return null;
-                }), Collections.emptyMap())
-            ),
-            new HashMap<>(ScriptModule.CORE_CONTEXTS)
-        );
-        Script script = new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap());
-        IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random(), Collections.emptyMap());
-        ScriptProcessor processor = new ScriptProcessor(randomAlphaOfLength(10), null, script, null, scriptService);
-        processor.execute(ingestDocument);
-        assertWarnings("[types removal] Looking up doc types [_type] in scripts is deprecated.");
-    }
 }
diff --git a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/URLDecodeProcessorTests.java b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/URLDecodeProcessorTests.java
index 81ed3c89768b7..3d68648825594 100644
--- a/modules/ingest-common/src/test/java/org/opensearch/ingest/common/URLDecodeProcessorTests.java
+++ b/modules/ingest-common/src/test/java/org/opensearch/ingest/common/URLDecodeProcessorTests.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.ingest.common;
 
-import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 
 public class URLDecodeProcessorTests extends AbstractStringProcessorTestCase<String> {
     @Override
     protected String modifyInput(String input) {
-        return "Hello%20G%C3%BCnter" + input;
+        return "Hello%20G%C3%BCnter" + urlEncode(input);
     }
 
     @Override
@@ -48,10 +49,10 @@ protected AbstractStringProcessor<String> newProcessor(String field, boolean ign
 
     @Override
     protected String expectedResult(String input) {
-        try {
-            return "Hello Günter" + URLDecoder.decode(input, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-            throw new IllegalArgumentException("invalid");
-        }
+        return "Hello Günter" + URLDecoder.decode(urlEncode(input), StandardCharsets.UTF_8);
+    }
+
+    private static String urlEncode(String s) {
+        return URLEncoder.encode(s, StandardCharsets.UTF_8);
     }
 }
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/10_basic.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/10_basic.yml
index 8a803eae1fc3d..f44cc1f9f9fcf 100644
--- a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/10_basic.yml
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/10_basic.yml
@@ -5,34 +5,34 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: ingest-common } }
-    - contains:  { nodes.$master.ingest.processors: { type: append } }
-    - contains:  { nodes.$master.ingest.processors: { type: bytes } }
-    - contains:  { nodes.$master.ingest.processors: { type: convert } }
-    - contains:  { nodes.$master.ingest.processors: { type: date } }
-    - contains:  { nodes.$master.ingest.processors: { type: date_index_name } }
-    - contains:  { nodes.$master.ingest.processors: { type: dissect } }
-    - contains:  { nodes.$master.ingest.processors: { type: dot_expander } }
-    - contains:  { nodes.$master.ingest.processors: { type: fail } }
-    - contains:  { nodes.$master.ingest.processors: { type: foreach } }
-    - contains:  { nodes.$master.ingest.processors: { type: grok } }
-    - contains:  { nodes.$master.ingest.processors: { type: gsub } }
-    - contains:  { nodes.$master.ingest.processors: { type: html_strip } }
-    - contains:  { nodes.$master.ingest.processors: { type: join } }
-    - contains:  { nodes.$master.ingest.processors: { type: json } }
-    - contains:  { nodes.$master.ingest.processors: { type: kv } }
-    - contains:  { nodes.$master.ingest.processors: { type: lowercase } }
-    - contains:  { nodes.$master.ingest.processors: { type: remove } }
-    - contains:  { nodes.$master.ingest.processors: { type: rename } }
-    - contains:  { nodes.$master.ingest.processors: { type: script } }
-    - contains:  { nodes.$master.ingest.processors: { type: set } }
-    - contains:  { nodes.$master.ingest.processors: { type: sort } }
-    - contains:  { nodes.$master.ingest.processors: { type: split } }
-    - contains:  { nodes.$master.ingest.processors: { type: trim } }
-    - contains:  { nodes.$master.ingest.processors: { type: uppercase } }
+    - contains:  { nodes.$cluster_manager.modules: { name: ingest-common } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: append } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: bytes } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: convert } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: date } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: date_index_name } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: dissect } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: dot_expander } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: fail } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: foreach } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: grok } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: gsub } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: html_strip } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: join } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: json } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: kv } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: lowercase } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: remove } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: rename } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: script } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: set } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: sort } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: split } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: trim } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: uppercase } }
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/120_grok.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/120_grok.yml
index 14c70c17265af..c0aec0e3d7392 100644
--- a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/120_grok.yml
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/120_grok.yml
@@ -134,7 +134,6 @@ teardown:
             "docs": [
               {
                 "_index": "index",
-                "_type": "type",
                 "_id": "id",
                 "_source": {
                   "field": "abc2xyz"
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/220_drop_processor.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/220_drop_processor.yml
index 77a1df81a296a..ef8332c2670d0 100644
--- a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/220_drop_processor.yml
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/220_drop_processor.yml
@@ -91,4 +91,3 @@ teardown:
     get:
       index: test
       id: 3
-
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/280_rename_processor.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/280_rename_processor.yml
new file mode 100644
index 0000000000000..96b2256bcc1dc
--- /dev/null
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/280_rename_processor.yml
@@ -0,0 +1,66 @@
+---
+teardown:
+  - do:
+      ingest.delete_pipeline:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test rename processor with non-existing field and without ignore_missing":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "rename" : {
+                  "field" : "{{field_foo}}",
+                  "target_field" : "bar"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: '/field path cannot be null nor empty/'
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: { message: "foo bar baz" }
+
+---
+"Test rename processor with non-existing field and ignore_missing":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "rename" : {
+                  "field" : "{{field_foo}}",
+                  "target_field" : "bar",
+                  "ignore_missing" : true
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: { message: "foo bar baz" }
+
+  - do:
+      get:
+        index: test
+        id: 1
+  - match: { _source.message: "foo bar baz" }
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/290_remove_processor.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/290_remove_processor.yml
new file mode 100644
index 0000000000000..ff5a17136afa2
--- /dev/null
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/290_remove_processor.yml
@@ -0,0 +1,93 @@
+---
+teardown:
+  - do:
+      ingest.delete_pipeline:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test remove processor with non-existing field and without ignore_missing":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "{{unknown}}"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /field path cannot be null nor empty/
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: { message: "foo bar baz" }
+
+---
+"Test remove processor with resolved field path doesn't exist":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "{{foo}}"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /field \[bar\] doesn\'t exist/
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: {
+          message: "foo bar baz",
+          foo: "bar"
+        }
+
+---
+"Test remove processor with non-existing field and ignore_missing":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "{{unknown}}",
+                  "ignore_missing" : true
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: { message: "foo bar baz" }
+
+  - do:
+      get:
+        index: test
+        id: 1
+  - match: { _source.message: "foo bar baz" }
diff --git a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/70_bulk.yml b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/70_bulk.yml
index 5b442456e64d0..2dfa17174b139 100644
--- a/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/70_bulk.yml
+++ b/modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/70_bulk.yml
@@ -77,21 +77,21 @@ teardown:
 
   - do:
       cluster.state: {}
-    # Get master node id
-  - set: { master_node: master }
+    # Get cluster-manager node id
+  - set: { cluster_manager_node: cluster_manager }
 
   - do:
       nodes.stats:
         metric: [ ingest ]
   #we can't assert anything here since we might have more than one node in the cluster
-  - gte: {nodes.$master.ingest.total.count: 0}
-  - gte: {nodes.$master.ingest.total.failed: 0}
-  - gte: {nodes.$master.ingest.total.time_in_millis: 0}
-  - match: {nodes.$master.ingest.total.current: 0}
-  - gte: {nodes.$master.ingest.pipelines.pipeline1.count: 0}
-  - match: {nodes.$master.ingest.pipelines.pipeline1.failed: 0}
-  - gte: {nodes.$master.ingest.pipelines.pipeline1.time_in_millis: 0}
-  - match: {nodes.$master.ingest.pipelines.pipeline1.current: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.count: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.failed: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.time_in_millis: 0}
+  - match: {nodes.$cluster_manager.ingest.total.current: 0}
+  - gte: {nodes.$cluster_manager.ingest.pipelines.pipeline1.count: 0}
+  - match: {nodes.$cluster_manager.ingest.pipelines.pipeline1.failed: 0}
+  - gte: {nodes.$cluster_manager.ingest.pipelines.pipeline1.time_in_millis: 0}
+  - match: {nodes.$cluster_manager.ingest.pipelines.pipeline1.current: 0}
 
 ---
 "Test bulk request with default pipeline":
@@ -113,21 +113,21 @@ teardown:
 
   - do:
       cluster.state: {}
-  # Get master node id
-  - set: { master_node: master }
+  # Get cluster-manager node id
+  - set: { cluster_manager_node: cluster_manager }
 
   - do:
       nodes.stats:
         metric: [ ingest ]
   #we can't assert anything here since we might have more than one node in the cluster
-  - gte: {nodes.$master.ingest.total.count: 0}
-  - gte: {nodes.$master.ingest.total.failed: 0}
-  - gte: {nodes.$master.ingest.total.time_in_millis: 0}
-  - match: {nodes.$master.ingest.total.current: 0}
-  - gte: {nodes.$master.ingest.pipelines.pipeline2.count: 0}
-  - match: {nodes.$master.ingest.pipelines.pipeline2.failed: 0}
-  - gte: {nodes.$master.ingest.pipelines.pipeline2.time_in_millis: 0}
-  - match: {nodes.$master.ingest.pipelines.pipeline2.current: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.count: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.failed: 0}
+  - gte: {nodes.$cluster_manager.ingest.total.time_in_millis: 0}
+  - match: {nodes.$cluster_manager.ingest.total.current: 0}
+  - gte: {nodes.$cluster_manager.ingest.pipelines.pipeline2.count: 0}
+  - match: {nodes.$cluster_manager.ingest.pipelines.pipeline2.failed: 0}
+  - gte: {nodes.$cluster_manager.ingest.pipelines.pipeline2.time_in_millis: 0}
+  - match: {nodes.$cluster_manager.ingest.pipelines.pipeline2.current: 0}
 
   - do:
       get:
diff --git a/modules/ingest-geoip/build.gradle b/modules/ingest-geoip/build.gradle
index f78dc49e9fb8a..129c40666028f 100644
--- a/modules/ingest-geoip/build.gradle
+++ b/modules/ingest-geoip/build.gradle
@@ -39,11 +39,11 @@ opensearchplugin {
 }
 
 dependencies {
-  api('com.maxmind.geoip2:geoip2:2.16.1')
+  api('com.maxmind.geoip2:geoip2:4.1.0')
   // geoip2 dependencies:
+  api('com.maxmind.db:maxmind-db:3.0.0')
   api("com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}")
-  api("com.fasterxml.jackson.core:jackson-databind:${versions.jackson}")
-  api('com.maxmind.db:maxmind-db:2.0.0')
+  api("com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}")
 
   testImplementation 'org.elasticsearch:geolite2-databases:20191119'
 }
@@ -67,24 +67,6 @@ tasks.named("bundlePlugin").configure {
   }
 }
 
-tasks.named("thirdPartyAudit").configure {
-  ignoreMissingClasses(
-          // geoip WebServiceClient needs apache http client, but we're not using WebServiceClient:
-          'org.apache.http.HttpEntity',
-          'org.apache.http.HttpResponse',
-          'org.apache.http.StatusLine',
-          'org.apache.http.client.config.RequestConfig$Builder',
-          'org.apache.http.client.config.RequestConfig',
-          'org.apache.http.client.methods.CloseableHttpResponse',
-          'org.apache.http.client.methods.HttpGet',
-          'org.apache.http.client.utils.URIBuilder',
-          'org.apache.http.impl.auth.BasicScheme',
-          'org.apache.http.impl.client.CloseableHttpClient',
-          'org.apache.http.impl.client.HttpClientBuilder',
-          'org.apache.http.util.EntityUtils'
-  )
-}
-
 if (Os.isFamily(Os.FAMILY_WINDOWS)) {
   tasks.named("test").configure {
     // Windows cannot cleanup database files properly unless it loads everything on heap.
diff --git a/modules/ingest-geoip/licenses/geoip2-2.16.1.jar.sha1 b/modules/ingest-geoip/licenses/geoip2-2.16.1.jar.sha1
deleted file mode 100644
index 0221476794d3a..0000000000000
--- a/modules/ingest-geoip/licenses/geoip2-2.16.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c92040bd6ef2cb59be71c6749d08c141ca546caf
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/geoip2-4.1.0.jar.sha1 b/modules/ingest-geoip/licenses/geoip2-4.1.0.jar.sha1
new file mode 100644
index 0000000000000..0d124299e4cfb
--- /dev/null
+++ b/modules/ingest-geoip/licenses/geoip2-4.1.0.jar.sha1
@@ -0,0 +1 @@
+b6b356cc91863409ba3475a148ee11a3a6d6aa4b
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/jackson-annotations-2.13.2.jar.sha1 b/modules/ingest-geoip/licenses/jackson-annotations-2.13.2.jar.sha1
deleted file mode 100644
index ecd3fb49d5b12..0000000000000
--- a/modules/ingest-geoip/licenses/jackson-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ec18851f1976d5b810ae1a5fcc32520d2d38f77a
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/jackson-annotations-2.15.2.jar.sha1 b/modules/ingest-geoip/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/modules/ingest-geoip/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/jackson-databind-2.13.2.jar.sha1 b/modules/ingest-geoip/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/modules/ingest-geoip/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/jackson-databind-2.15.2.jar.sha1 b/modules/ingest-geoip/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/modules/ingest-geoip/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/maxmind-db-2.0.0.jar.sha1 b/modules/ingest-geoip/licenses/maxmind-db-2.0.0.jar.sha1
deleted file mode 100644
index 32c18f89c6a29..0000000000000
--- a/modules/ingest-geoip/licenses/maxmind-db-2.0.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e7e0fd82da0a160b7928ba214e699a7e6a74fff4
\ No newline at end of file
diff --git a/modules/ingest-geoip/licenses/maxmind-db-3.0.0.jar.sha1 b/modules/ingest-geoip/licenses/maxmind-db-3.0.0.jar.sha1
new file mode 100644
index 0000000000000..89b0c4c49b450
--- /dev/null
+++ b/modules/ingest-geoip/licenses/maxmind-db-3.0.0.jar.sha1
@@ -0,0 +1 @@
+79dcda62168a77caf595f8fda101baa17fef125d
\ No newline at end of file
diff --git a/modules/ingest-geoip/src/internalClusterTest/java/org/opensearch/ingest/geoip/GeoIpProcessorNonIngestNodeIT.java b/modules/ingest-geoip/src/internalClusterTest/java/org/opensearch/ingest/geoip/GeoIpProcessorNonIngestNodeIT.java
index e88c77b8e33f4..5658f083db2d2 100644
--- a/modules/ingest-geoip/src/internalClusterTest/java/org/opensearch/ingest/geoip/GeoIpProcessorNonIngestNodeIT.java
+++ b/modules/ingest-geoip/src/internalClusterTest/java/org/opensearch/ingest/geoip/GeoIpProcessorNonIngestNodeIT.java
@@ -36,17 +36,17 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.ingest.PutPipelineRequest;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.NodeRoles;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.StreamsUtils;
 
 import java.io.ByteArrayInputStream;
@@ -158,7 +158,7 @@ public void testLazyLoading() throws IOException {
             builder.endObject();
             bytes = BytesReference.bytes(builder);
         }
-        assertAcked(client().admin().cluster().putPipeline(new PutPipelineRequest("geoip", bytes, XContentType.JSON)).actionGet());
+        assertAcked(client().admin().cluster().putPipeline(new PutPipelineRequest("geoip", bytes, MediaTypeRegistry.JSON)).actionGet());
         // the geo-IP databases should not be loaded on any nodes as they are all non-ingest nodes
         Arrays.stream(internalCluster().getNodeNames()).forEach(node -> assertDatabaseLoadStatus(node, false));
 
diff --git a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
index 1cafae0e50cef..0c2cde786dd40 100644
--- a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
+++ b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
@@ -33,11 +33,12 @@
 package org.opensearch.ingest.geoip;
 
 import com.maxmind.geoip2.DatabaseReader;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -71,7 +72,7 @@ class DatabaseReaderLazyLoader implements Closeable {
 
     /**
      * Read the database type from the database. We do this manually instead of relying on the built-in mechanism to avoid reading the
-     * entire database into memory merely to read the type. This is especially important to maintain on master nodes where pipelines are
+     * entire database into memory merely to read the type. This is especially important to maintain on cluster-manager nodes where pipelines are
      * validated. If we read the entire database into memory, we could potentially run into low-memory constraints on such nodes where
      * loading this data would otherwise be wasteful if they are not also ingest nodes.
      *
diff --git a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/GeoIpProcessor.java b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/GeoIpProcessor.java
index 384ae6f14dc4d..6801d85d1424c 100644
--- a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/GeoIpProcessor.java
+++ b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/GeoIpProcessor.java
@@ -42,6 +42,7 @@
 import com.maxmind.geoip2.record.Country;
 import com.maxmind.geoip2.record.Location;
 import com.maxmind.geoip2.record.Subdivision;
+
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.SpecialPermission;
 import org.opensearch.common.network.InetAddresses;
@@ -364,7 +365,7 @@ private Map<String, Object> retrieveAsnGeoData(InetAddress ipAddress) {
             })
         );
 
-        Integer asn = response.getAutonomousSystemNumber();
+        Long asn = response.getAutonomousSystemNumber();
         String organization_name = response.getAutonomousSystemOrganization();
         Network network = response.getNetwork();
 
diff --git a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/IngestGeoIpPlugin.java b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/IngestGeoIpPlugin.java
index 6af408c185374..8e51255b6123d 100644
--- a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/IngestGeoIpPlugin.java
+++ b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/IngestGeoIpPlugin.java
@@ -37,13 +37,14 @@
 import com.maxmind.db.Reader;
 import com.maxmind.geoip2.DatabaseReader;
 import com.maxmind.geoip2.model.AbstractResponse;
+
 import org.opensearch.common.Booleans;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.cache.Cache;
 import org.opensearch.common.cache.CacheBuilder;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.ingest.Processor;
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.plugins.Plugin;
diff --git a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorFactoryTests.java b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorFactoryTests.java
index cda2f5692b0db..ac5a0f8a7d886 100644
--- a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorFactoryTests.java
+++ b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorFactoryTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.ingest.geoip;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Randomness;
 import org.opensearch.index.VersionType;
diff --git a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorTests.java b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorTests.java
index f06802af8b571..e0c93d8584878 100644
--- a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorTests.java
+++ b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/GeoIpProcessorTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.ingest.geoip;
 
 import com.maxmind.geoip2.DatabaseReader;
+
 import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.ingest.IngestDocument;
@@ -308,7 +309,7 @@ public void testAsn() throws Exception {
         Map<String, Object> geoData = (Map<String, Object>) ingestDocument.getSourceAndMetadata().get("target_field");
         assertThat(geoData.size(), equalTo(4));
         assertThat(geoData.get("ip"), equalTo(ip));
-        assertThat(geoData.get("asn"), equalTo(1136));
+        assertThat(geoData.get("asn"), equalTo(1136L));
         assertThat(geoData.get("organization_name"), equalTo("KPN B.V."));
         assertThat(geoData.get("network"), equalTo("82.168.0.0/14"));
     }
diff --git a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/IngestGeoIpPluginTests.java b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/IngestGeoIpPluginTests.java
index 540d68b0982eb..a1120675872bb 100644
--- a/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/IngestGeoIpPluginTests.java
+++ b/modules/ingest-geoip/src/test/java/org/opensearch/ingest/geoip/IngestGeoIpPluginTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.ingest.geoip;
 
 import com.maxmind.geoip2.model.AbstractResponse;
+
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.ingest.geoip.IngestGeoIpPlugin.GeoIpCache;
 import org.opensearch.test.OpenSearchTestCase;
@@ -65,11 +66,9 @@ public void testThrowsFunctionsException() {
         GeoIpCache cache = new GeoIpCache(1);
         IllegalArgumentException ex = expectThrows(
             IllegalArgumentException.class,
-            () -> cache.putIfAbsent(
-                InetAddresses.forString("127.0.0.1"),
-                AbstractResponse.class,
-                ip -> { throw new IllegalArgumentException("bad"); }
-            )
+            () -> cache.putIfAbsent(InetAddresses.forString("127.0.0.1"), AbstractResponse.class, ip -> {
+                throw new IllegalArgumentException("bad");
+            })
         );
         assertEquals("bad", ex.getMessage());
     }
diff --git a/modules/ingest-geoip/src/yamlRestTest/resources/rest-api-spec/test/ingest_geoip/10_basic.yml b/modules/ingest-geoip/src/yamlRestTest/resources/rest-api-spec/test/ingest_geoip/10_basic.yml
index 5cd45da2bda38..3b414022ede66 100644
--- a/modules/ingest-geoip/src/yamlRestTest/resources/rest-api-spec/test/ingest_geoip/10_basic.yml
+++ b/modules/ingest-geoip/src/yamlRestTest/resources/rest-api-spec/test/ingest_geoip/10_basic.yml
@@ -5,10 +5,10 @@
     - do:
         cluster.state: {}
 
-    - set: {master_node: master}
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: ingest-geoip } }
-    - contains:  { nodes.$master.ingest.processors: { type: geoip } }
+    - contains:  { nodes.$cluster_manager.modules: { name: ingest-geoip } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: geoip } }
diff --git a/modules/ingest-user-agent/build.gradle b/modules/ingest-user-agent/build.gradle
index cd04925287b8f..a3752ad1c7f7e 100644
--- a/modules/ingest-user-agent/build.gradle
+++ b/modules/ingest-user-agent/build.gradle
@@ -43,4 +43,3 @@ restResources {
 testClusters.all {
   extraConfigFile 'ingest-user-agent/test-regexes.yml', file('src/test/test-regexes.yml')
 }
-
diff --git a/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentParser.java b/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentParser.java
index 7dc3ee4346371..88129ffb922b8 100644
--- a/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentParser.java
+++ b/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentParser.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -68,7 +68,7 @@ final class UserAgentParser {
 
     private void init(InputStream regexStream) throws IOException {
         // EMPTY is safe here because we don't use namedObject
-        XContentParser yamlParser = XContentFactory.xContent(XContentType.YAML)
+        XContentParser yamlParser = XContentType.YAML.xContent()
             .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, regexStream);
 
         XContentParser.Token token = yamlParser.nextToken();
diff --git a/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentProcessor.java b/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentProcessor.java
index 0625f1f8fd1af..5c6106b694144 100644
--- a/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentProcessor.java
+++ b/modules/ingest-user-agent/src/main/java/org/opensearch/ingest/useragent/UserAgentProcessor.java
@@ -346,7 +346,7 @@ public UserAgentProcessor create(
                 deprecationLogger.deprecate(
                     "ecs_false_non_common_schema",
                     "setting [ecs] to false for non-common schema "
-                        + "format is deprecated and will be removed in 8.0, set to true or remove to use the non-deprecated format"
+                        + "format is deprecated and will be removed in 3.0, set to true or remove to use the non-deprecated format"
                 );
             }
 
diff --git a/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorFactoryTests.java b/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorFactoryTests.java
index 72815a37f46de..bfb0e2c9ab9a4 100644
--- a/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorFactoryTests.java
+++ b/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorFactoryTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.ingest.useragent;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.BeforeClass;
 
diff --git a/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorTests.java b/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorTests.java
index 51ff8aae21365..b7dd45b209113 100644
--- a/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorTests.java
+++ b/modules/ingest-user-agent/src/test/java/org/opensearch/ingest/useragent/UserAgentProcessorTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.ingest.useragent;
 
-import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.ingest.IngestDocument;
+import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.BeforeClass;
 
diff --git a/modules/ingest-user-agent/src/test/test-regexes.yml b/modules/ingest-user-agent/src/test/test-regexes.yml
index e41dec700c047..8815c85c7c6e9 100644
--- a/modules/ingest-user-agent/src/test/test-regexes.yml
+++ b/modules/ingest-user-agent/src/test/test-regexes.yml
@@ -1,3 +1,3 @@
 user_agent_parsers:
   - regex: '.*'
-    family_replacement: 'Test'
\ No newline at end of file
+    family_replacement: 'Test'
diff --git a/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/10_basic.yml b/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/10_basic.yml
index 327d9cf451257..c0e1d14489a64 100644
--- a/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/10_basic.yml
+++ b/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/10_basic.yml
@@ -5,10 +5,10 @@
     - do:
         cluster.state: {}
 
-    - set: {master_node: master}
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: ingest-user-agent } }
-    - contains:  { nodes.$master.ingest.processors: { type: user_agent } }
+    - contains:  { nodes.$cluster_manager.modules: { name: ingest-user-agent } }
+    - contains:  { nodes.$cluster_manager.ingest.processors: { type: user_agent } }
diff --git a/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/20_useragent_processor.yml b/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/20_useragent_processor.yml
index c7ab1751d1b0d..a3c9afc02dac4 100644
--- a/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/20_useragent_processor.yml
+++ b/modules/ingest-user-agent/src/yamlRestTest/resources/rest-api-spec/test/ingest-useragent/20_useragent_processor.yml
@@ -87,7 +87,7 @@
 
   - do:
       allowed_warnings:
-        - "setting [ecs] to false for non-common schema format is deprecated and will be removed in 8.0, set to true or remove to use the non-deprecated format"
+        - "setting [ecs] to false for non-common schema format is deprecated and will be removed in 3.0, set to true or remove to use the non-deprecated format"
         - "the [os_major] property is deprecated for the user-agent processor"
       ingest.put_pipeline:
         id: "my_pipeline"
diff --git a/modules/lang-expression/build.gradle b/modules/lang-expression/build.gradle
index e3feacd71f060..0070923dc4be5 100644
--- a/modules/lang-expression/build.gradle
+++ b/modules/lang-expression/build.gradle
@@ -37,10 +37,10 @@ opensearchplugin {
 
 dependencies {
   api "org.apache.lucene:lucene-expressions:${versions.lucene}"
-  api 'org.antlr:antlr4-runtime:4.9.3'
-  api 'org.ow2.asm:asm:9.2'
-  api 'org.ow2.asm:asm-commons:9.2'
-  api 'org.ow2.asm:asm-tree:9.2'
+  api "org.antlr:antlr4-runtime:${versions.antlr4}"
+  api "org.ow2.asm:asm:${versions.asm}"
+  api "org.ow2.asm:asm-commons:${versions.asm}"
+  api "org.ow2.asm:asm-tree:${versions.asm}"
 }
 restResources {
   restApi {
@@ -52,4 +52,3 @@ tasks.named("dependencyLicenses").configure {
   mapping from: /lucene-.*/, to: 'lucene'
   mapping from: /asm-.*/, to: 'asm'
 }
-
diff --git a/modules/lang-expression/licenses/antlr4-runtime-4.11.1.jar.sha1 b/modules/lang-expression/licenses/antlr4-runtime-4.11.1.jar.sha1
new file mode 100644
index 0000000000000..f1b328a6de624
--- /dev/null
+++ b/modules/lang-expression/licenses/antlr4-runtime-4.11.1.jar.sha1
@@ -0,0 +1 @@
+069214c1de1960040729702eb58deac8827135e7
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/antlr4-runtime-4.9.3.jar.sha1 b/modules/lang-expression/licenses/antlr4-runtime-4.9.3.jar.sha1
deleted file mode 100644
index 13a2367439ede..0000000000000
--- a/modules/lang-expression/licenses/antlr4-runtime-4.9.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-81befc16ebedb8b8aea3e4c0835dd5ca7e8523a8
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-9.2.jar.sha1 b/modules/lang-expression/licenses/asm-9.2.jar.sha1
deleted file mode 100644
index 28f456d3cbcb2..0000000000000
--- a/modules/lang-expression/licenses/asm-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-81a03f76019c67362299c40e0ba13405f5467bff
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-9.6.jar.sha1 b/modules/lang-expression/licenses/asm-9.6.jar.sha1
new file mode 100644
index 0000000000000..2d9e6a9d3cfd6
--- /dev/null
+++ b/modules/lang-expression/licenses/asm-9.6.jar.sha1
@@ -0,0 +1 @@
+aa205cf0a06dbd8e04ece91c0b37c3f5d567546a
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-commons-9.2.jar.sha1 b/modules/lang-expression/licenses/asm-commons-9.2.jar.sha1
deleted file mode 100644
index 7beb3d29afe86..0000000000000
--- a/modules/lang-expression/licenses/asm-commons-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f4d7f0fc9054386f2893b602454d48e07d4fbead
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-commons-9.6.jar.sha1 b/modules/lang-expression/licenses/asm-commons-9.6.jar.sha1
new file mode 100644
index 0000000000000..a0814f495771f
--- /dev/null
+++ b/modules/lang-expression/licenses/asm-commons-9.6.jar.sha1
@@ -0,0 +1 @@
+f1a9e5508eff490744144565c47326c8648be309
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-tree-9.2.jar.sha1 b/modules/lang-expression/licenses/asm-tree-9.2.jar.sha1
deleted file mode 100644
index 7b486521ecef3..0000000000000
--- a/modules/lang-expression/licenses/asm-tree-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d96c99a30f5e1a19b0e609dbb19a44d8518ac01e
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/asm-tree-9.6.jar.sha1 b/modules/lang-expression/licenses/asm-tree-9.6.jar.sha1
new file mode 100644
index 0000000000000..101eb03b4b736
--- /dev/null
+++ b/modules/lang-expression/licenses/asm-tree-9.6.jar.sha1
@@ -0,0 +1 @@
+c0cdda9d211e965d2a4448aa3fd86110f2f8c2de
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/lucene-expressions-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/modules/lang-expression/licenses/lucene-expressions-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index fb85ff4827c36..0000000000000
--- a/modules/lang-expression/licenses/lucene-expressions-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c7317bb4e72b820a516e0c8a90beac5acc82c2e2
\ No newline at end of file
diff --git a/modules/lang-expression/licenses/lucene-expressions-9.7.0.jar.sha1 b/modules/lang-expression/licenses/lucene-expressions-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..ecf696b4b3b83
--- /dev/null
+++ b/modules/lang-expression/licenses/lucene-expressions-9.7.0.jar.sha1
@@ -0,0 +1 @@
+297e1cfade4ef71466cc9d4f361d81807c8dc4c8
\ No newline at end of file
diff --git a/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/MoreExpressionIT.java b/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/MoreExpressionIT.java
index 952b00dda608c..80974b3b3f104 100644
--- a/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/MoreExpressionIT.java
+++ b/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/MoreExpressionIT.java
@@ -32,14 +32,18 @@
 
 package org.opensearch.script.expression;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.update.UpdateRequestBuilder;
 import org.opensearch.common.lucene.search.function.CombineFunction;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.functionscore.ScoreFunctionBuilders;
 import org.opensearch.index.query.functionscore.ScriptScoreFunctionBuilder;
@@ -53,9 +57,10 @@
 import org.opensearch.search.aggregations.pipeline.SimpleValue;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -64,6 +69,7 @@
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.bucketScript;
@@ -74,7 +80,24 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 // TODO: please convert to unit tests!
-public class MoreExpressionIT extends OpenSearchIntegTestCase {
+public class MoreExpressionIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MoreExpressionIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/StoredExpressionIT.java b/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/StoredExpressionIT.java
index 5aade265439d2..f3c994521692c 100644
--- a/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/StoredExpressionIT.java
+++ b/modules/lang-expression/src/internalClusterTest/java/org/opensearch/script/expression/StoredExpressionIT.java
@@ -32,24 +32,47 @@
 
 package org.opensearch.script.expression;
 
-import org.opensearch.common.bytes.BytesArray;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.containsString;
 
 //TODO: please convert to unit tests!
-public class StoredExpressionIT extends OpenSearchIntegTestCase {
+public class StoredExpressionIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public StoredExpressionIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
         Settings.Builder builder = Settings.builder().put(super.nodeSettings(nodeOrdinal));
@@ -67,9 +90,9 @@ public void testAllOpsDisabledIndexedScripts() throws IOException {
             .cluster()
             .preparePutStoredScript()
             .setId("script1")
-            .setContent(new BytesArray("{\"script\": {\"lang\": \"expression\", \"source\": \"2\"} }"), XContentType.JSON)
+            .setContent(new BytesArray("{\"script\": {\"lang\": \"expression\", \"source\": \"2\"} }"), MediaTypeRegistry.JSON)
             .get();
-        client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", MediaTypeRegistry.JSON).get();
         try {
             client().prepareUpdate("test", "1").setScript(new Script(ScriptType.STORED, null, "script1", Collections.emptyMap())).get();
             fail("update script should have been rejected");
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/CountMethodValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/CountMethodValueSource.java
index 97ea247c15bbd..77580f88c16f7 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/CountMethodValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/CountMethodValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 
 import java.io.IOException;
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateMethodValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateMethodValueSource.java
index 6aa7e640c77cb..31be3cc3b1264 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateMethodValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateMethodValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.NumericDoubleValues;
 import org.opensearch.search.MultiValueMode;
 
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateObjectValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateObjectValueSource.java
index 1ab778008e8c3..69d7b5ad7f769 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateObjectValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/DateObjectValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.NumericDoubleValues;
 import org.opensearch.search.MultiValueMode;
 import org.joda.time.DateTimeZone;
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/EmptyMemberValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/EmptyMemberValueSource.java
index da400b27b0fd3..1fba4241f80f3 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/EmptyMemberValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/EmptyMemberValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 
 import java.io.IOException;
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionAggregationScript.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionAggregationScript.java
index ba131473be4fb..5eebb9c4d60ad 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionAggregationScript.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionAggregationScript.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.script.expression;
 
-import java.io.IOException;
 import org.apache.lucene.expressions.Bindings;
 import org.apache.lucene.expressions.Expression;
 import org.apache.lucene.expressions.SimpleBindings;
@@ -42,6 +41,8 @@
 import org.opensearch.script.AggregationScript;
 import org.opensearch.script.GeneralScriptException;
 
+import java.io.IOException;
+
 /**
  * A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
  * of a {@link AggregationScript}.
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionNumberSortScript.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionNumberSortScript.java
index fc50e7355f492..72710591fece8 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionNumberSortScript.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionNumberSortScript.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.script.expression;
 
-import java.io.IOException;
 import org.apache.lucene.expressions.Bindings;
 import org.apache.lucene.expressions.Expression;
 import org.apache.lucene.expressions.SimpleBindings;
@@ -42,6 +41,8 @@
 import org.opensearch.script.GeneralScriptException;
 import org.opensearch.script.NumberSortScript;
 
+import java.io.IOException;
+
 /**
  * A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
  * of a {@link NumberSortScript}.
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionPlugin.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionPlugin.java
index 440a03c63bd98..47cafc377e701 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionPlugin.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionPlugin.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.script.expression;
 
-import java.util.Collection;
-
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ScriptPlugin;
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.ScriptEngine;
 
+import java.util.Collection;
+
 public class ExpressionPlugin extends Plugin implements ScriptPlugin {
 
     @Override
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScoreScript.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScoreScript.java
index 6be299146a181..3932559f7685c 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScoreScript.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScoreScript.java
@@ -66,7 +66,7 @@ public boolean needs_score() {
 
     @Override
     public ScoreScript newInstance(final LeafReaderContext leaf) throws IOException {
-        return new ScoreScript(null, null, null) {
+        return new ScoreScript(null, null, null, null) {
             // Fake the scorer until setScorer is called.
             DoubleValues values = source.getValues(leaf, new DoubleValues() {
                 @Override
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScriptEngine.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScriptEngine.java
index 1c3dc69359952..035d2402857e0 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScriptEngine.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionScriptEngine.java
@@ -37,6 +37,7 @@
 import org.apache.lucene.expressions.js.JavascriptCompiler;
 import org.apache.lucene.expressions.js.VariableContext;
 import org.apache.lucene.search.DoubleValuesSource;
+import org.apache.lucene.search.IndexSearcher;
 import org.opensearch.SpecialPermission;
 import org.opensearch.common.Nullable;
 import org.opensearch.index.fielddata.IndexFieldData;
@@ -110,7 +111,7 @@ public FilterScript.LeafFactory newFactory(Map<String, Object> params, SearchLoo
 
         contexts.put(ScoreScript.CONTEXT, (Expression expr) -> new ScoreScript.Factory() {
             @Override
-            public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+            public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher) {
                 return newScoreScript(expr, lookup, params);
             }
 
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionTermSetQueryScript.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionTermSetQueryScript.java
index 0c14a45804c3e..39be670b7e303 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionTermSetQueryScript.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/ExpressionTermSetQueryScript.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.script.expression;
 
-import java.io.IOException;
 import org.apache.lucene.expressions.Bindings;
 import org.apache.lucene.expressions.Expression;
 import org.apache.lucene.expressions.SimpleBindings;
@@ -42,6 +41,8 @@
 import org.opensearch.script.GeneralScriptException;
 import org.opensearch.script.TermsSetQueryScript;
 
+import java.io.IOException;
+
 /**
  * A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
  * of a {@link TermsSetQueryScript}.
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/FieldDataValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/FieldDataValueSource.java
index c0488a267507c..21f9d0a94b0c9 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/FieldDataValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/FieldDataValueSource.java
@@ -35,8 +35,8 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.queries.function.ValueSource;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.NumericDoubleValues;
 import org.opensearch.search.MultiValueMode;
 
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLatitudeValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLatitudeValueSource.java
index b167393d1b864..3ae45503657be 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLatitudeValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLatitudeValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
 
 import java.io.IOException;
diff --git a/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLongitudeValueSource.java b/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLongitudeValueSource.java
index 10d836b7d219f..aa67b11833972 100644
--- a/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLongitudeValueSource.java
+++ b/modules/lang-expression/src/main/java/org/opensearch/script/expression/GeoLongitudeValueSource.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DoubleValues;
-import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
 
 import java.io.IOException;
diff --git a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionFieldScriptTests.java b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionFieldScriptTests.java
index d0941cbc9452f..143ff4f5c51bd 100644
--- a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionFieldScriptTests.java
+++ b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionFieldScriptTests.java
@@ -47,8 +47,8 @@
 import java.util.Collections;
 
 import static org.hamcrest.Matchers.equalTo;
-import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionNumberSortScriptTests.java b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionNumberSortScriptTests.java
index f3559da59f992..498c0542e9c3e 100644
--- a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionNumberSortScriptTests.java
+++ b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionNumberSortScriptTests.java
@@ -32,11 +32,8 @@
 
 package org.opensearch.script.expression;
 
-import java.io.IOException;
-import java.text.ParseException;
-import java.util.Collections;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
@@ -46,8 +43,12 @@
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.test.OpenSearchTestCase;
 
-import static org.mockito.Mockito.anyInt;
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.Collections;
+
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionTermsSetQueryTests.java b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionTermsSetQueryTests.java
index af7fc580f8a65..499f94afcb6af 100644
--- a/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionTermsSetQueryTests.java
+++ b/modules/lang-expression/src/test/java/org/opensearch/script/expression/ExpressionTermsSetQueryTests.java
@@ -32,11 +32,8 @@
 
 package org.opensearch.script.expression;
 
-import java.io.IOException;
-import java.text.ParseException;
-import java.util.Collections;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
@@ -46,8 +43,12 @@
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.test.OpenSearchTestCase;
 
-import static org.mockito.Mockito.anyInt;
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.Collections;
+
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/modules/lang-expression/src/yamlRestTest/resources/rest-api-spec/test/lang_expression/10_basic.yml b/modules/lang-expression/src/yamlRestTest/resources/rest-api-spec/test/lang_expression/10_basic.yml
index 00ad6f890b0e0..d56ad1a8a244c 100644
--- a/modules/lang-expression/src/yamlRestTest/resources/rest-api-spec/test/lang_expression/10_basic.yml
+++ b/modules/lang-expression/src/yamlRestTest/resources/rest-api-spec/test/lang_expression/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: lang-expression  } }
+    - contains:  { nodes.$cluster_manager.modules: { name: lang-expression  } }
diff --git a/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/MultiSearchTemplateIT.java b/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/MultiSearchTemplateIT.java
index 617f1f4f738a0..204082ba10ded 100644
--- a/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/MultiSearchTemplateIT.java
+++ b/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/MultiSearchTemplateIT.java
@@ -32,13 +32,16 @@
 
 package org.opensearch.script.mustache;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -47,6 +50,7 @@
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.arrayWithSize;
 import static org.hamcrest.Matchers.equalTo;
@@ -54,7 +58,24 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.core.Is.is;
 
-public class MultiSearchTemplateIT extends OpenSearchIntegTestCase {
+public class MultiSearchTemplateIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MultiSearchTemplateIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -72,15 +93,14 @@ public void testBasic() throws Exception {
         }
         indexRandom(true, indexRequestBuilders);
 
-        final String template = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("query")
-                .startObject("{{query_type}}")
-                .field("{{field_name}}", "{{field_value}}")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        final String template = jsonBuilder().startObject()
+            .startObject("query")
+            .startObject("{{query_type}}")
+            .field("{{field_name}}", "{{field_value}}")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         MultiSearchTemplateRequest multiRequest = new MultiSearchTemplateRequest();
 
diff --git a/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/SearchTemplateIT.java b/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/SearchTemplateIT.java
index 61f047a32f1c1..8799f3096452d 100644
--- a/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/SearchTemplateIT.java
+++ b/modules/lang-mustache/src/internalClusterTest/java/org/opensearch/script/mustache/SearchTemplateIT.java
@@ -35,9 +35,9 @@
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptResponse;
 import org.opensearch.action.bulk.BulkRequestBuilder;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -177,7 +177,7 @@ public void testIndexedTemplateClient() throws Exception {
                             + "  }"
                             + "}"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
@@ -185,11 +185,11 @@ public void testIndexedTemplateClient() throws Exception {
         assertNotNull(getResponse.getSource());
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", MediaTypeRegistry.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
@@ -224,16 +224,22 @@ public void testIndexedTemplate() throws Exception {
             + "  }"
             + "}";
 
-        assertAcked(client().admin().cluster().preparePutStoredScript().setId("1a").setContent(new BytesArray(script), XContentType.JSON));
-        assertAcked(client().admin().cluster().preparePutStoredScript().setId("2").setContent(new BytesArray(script), XContentType.JSON));
-        assertAcked(client().admin().cluster().preparePutStoredScript().setId("3").setContent(new BytesArray(script), XContentType.JSON));
+        assertAcked(
+            client().admin().cluster().preparePutStoredScript().setId("1a").setContent(new BytesArray(script), MediaTypeRegistry.JSON)
+        );
+        assertAcked(
+            client().admin().cluster().preparePutStoredScript().setId("2").setContent(new BytesArray(script), MediaTypeRegistry.JSON)
+        );
+        assertAcked(
+            client().admin().cluster().preparePutStoredScript().setId("3").setContent(new BytesArray(script), MediaTypeRegistry.JSON)
+        );
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", MediaTypeRegistry.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
@@ -295,7 +301,7 @@ public void testIndexedTemplateOverwrite() throws Exception {
                     .cluster()
                     .preparePutStoredScript()
                     .setId("git01")
-                    .setContent(new BytesArray(query.replace("{{slop}}", Integer.toString(-1))), XContentType.JSON)
+                    .setContent(new BytesArray(query.replace("{{slop}}", Integer.toString(-1))), MediaTypeRegistry.JSON)
             );
 
             GetStoredScriptResponse getResponse = client().admin().cluster().prepareGetStoredScript("git01").get();
@@ -319,7 +325,7 @@ public void testIndexedTemplateOverwrite() throws Exception {
                     .cluster()
                     .preparePutStoredScript()
                     .setId("git01")
-                    .setContent(new BytesArray(query.replace("{{slop}}", Integer.toString(0))), XContentType.JSON)
+                    .setContent(new BytesArray(query.replace("{{slop}}", Integer.toString(0))), MediaTypeRegistry.JSON)
             );
 
             SearchTemplateResponse searchResponse = new SearchTemplateRequestBuilder(client()).setRequest(new SearchRequest("testindex"))
@@ -349,14 +355,14 @@ public void testIndexedTemplateWithArray() throws Exception {
             + "  }\n"
             + "}";
         assertAcked(
-            client().admin().cluster().preparePutStoredScript().setId("4").setContent(new BytesArray(multiQuery), XContentType.JSON)
+            client().admin().cluster().preparePutStoredScript().setId("4").setContent(new BytesArray(multiQuery), MediaTypeRegistry.JSON)
         );
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("1").setSource("{\"theField\":\"foo\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("2").setSource("{\"theField\":\"foo 2\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("3").setSource("{\"theField\":\"foo 3\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("4").setSource("{\"theField\":\"foo 4\"}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test").setId("5").setSource("{\"theField\":\"bar\"}", MediaTypeRegistry.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomMustacheFactory.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomMustacheFactory.java
index 09c52142dfea5..c8d28575fef47 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomMustacheFactory.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomMustacheFactory.java
@@ -33,6 +33,7 @@
 package org.opensearch.script.mustache;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
 import com.github.mustachejava.Code;
 import com.github.mustachejava.DefaultMustacheFactory;
 import com.github.mustachejava.DefaultMustacheVisitor;
@@ -44,9 +45,8 @@
 import com.github.mustachejava.codes.IterableCode;
 import com.github.mustachejava.codes.WriteCode;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.StringWriter;
@@ -215,7 +215,7 @@ protected Function<String, String> createFunction(Object resolved) {
                 if (resolved == null) {
                     return null;
                 }
-                try (XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent())) {
+                try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
                     if (resolved instanceof Iterable) {
                         builder.startArray();
                         for (Object o : (Iterable<?>) resolved) {
@@ -228,7 +228,7 @@ protected Function<String, String> createFunction(Object resolved) {
                         // Do not handle as JSON
                         return oh.stringify(resolved);
                     }
-                    return Strings.toString(builder);
+                    return builder.toString();
                 } catch (IOException e) {
                     throw new MustacheException("Failed to convert object to JSON", e);
                 }
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomReflectionObjectHandler.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomReflectionObjectHandler.java
index 57451a027c5d7..0adac121d77e3 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomReflectionObjectHandler.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/CustomReflectionObjectHandler.java
@@ -33,16 +33,17 @@
 package org.opensearch.script.mustache;
 
 import com.github.mustachejava.reflect.ReflectionObjectHandler;
-import org.opensearch.common.util.CollectionUtils;
+
 import org.opensearch.common.util.iterable.Iterables;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.lang.reflect.Array;
 import java.util.AbstractMap;
 import java.util.Collection;
-import java.util.Set;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
-import java.util.HashMap;
+import java.util.Set;
 
 final class CustomReflectionObjectHandler extends ReflectionObjectHandler {
 
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateRequest.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateRequest.java
index b645eeeedf151..dc3b52cd0b946 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateRequest.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateRequest.java
@@ -38,12 +38,12 @@
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateResponse.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateResponse.java
index 1802d03e20942..20d09849dfcea 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateResponse.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MultiSearchTemplateResponse.java
@@ -34,18 +34,19 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -206,6 +207,6 @@ public static MultiSearchTemplateResponse fromXContext(XContentParser parser) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustachePlugin.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustachePlugin.java
index 498dc2ac57cc7..bb02b0c1d16b8 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustachePlugin.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustachePlugin.java
@@ -33,13 +33,13 @@
 package org.opensearch.script.mustache;
 
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ScriptPlugin;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustacheScriptEngine.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustacheScriptEngine.java
index e94dac2a3bfad..f4d7198dc2124 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustacheScriptEngine.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/MustacheScriptEngine.java
@@ -34,6 +34,7 @@
 import com.github.mustachejava.Mustache;
 import com.github.mustachejava.MustacheException;
 import com.github.mustachejava.MustacheFactory;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestRenderSearchTemplateAction.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestRenderSearchTemplateAction.java
index 1cf61a24bbbb7..7a94fc45837d9 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestRenderSearchTemplateAction.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestRenderSearchTemplateAction.java
@@ -33,7 +33,7 @@
 package org.opensearch.script.mustache;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestSearchTemplateAction.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestSearchTemplateAction.java
index 68ba824955468..74a8d23958efa 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestSearchTemplateAction.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/RestSearchTemplateAction.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestStatusToXContentListener;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateRequest.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateRequest.java
index 6e8dc815eb552..1aabea30fc651 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateRequest.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateRequest.java
@@ -35,17 +35,18 @@
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.CompositeIndicesRequest;
+import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptType;
 
 import java.io.IOException;
@@ -57,7 +58,7 @@
 /**
  * A request to execute a search based on a search template.
  */
-public class SearchTemplateRequest extends ActionRequest implements CompositeIndicesRequest, ToXContentObject {
+public class SearchTemplateRequest extends ActionRequest implements IndicesRequest.Replaceable, CompositeIndicesRequest, ToXContentObject {
 
     private SearchRequest request;
     private boolean simulate = false;
@@ -207,8 +208,8 @@ public ActionRequestValidationException validate() {
             request.setScriptType(ScriptType.INLINE);
             if (parser.currentToken() == XContentParser.Token.START_OBJECT) {
                 // convert the template to json which is the only supported XContentType (see CustomMustacheFactory#createEncoder)
-                try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
-                    request.setScript(Strings.toString(builder.copyCurrentStructure(parser)));
+                try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
+                    request.setScript(builder.copyCurrentStructure(parser).toString());
                 } catch (IOException e) {
                     throw new ParsingException(parser.getTokenLocation(), "Could not parse inline template", e);
                 }
@@ -255,4 +256,19 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeMap(scriptParams);
         }
     }
+
+    @Override
+    public String[] indices() {
+        return request.indices();
+    }
+
+    @Override
+    public IndicesOptions indicesOptions() {
+        return request.indicesOptions();
+    }
+
+    @Override
+    public IndicesRequest indices(String... indices) {
+        return request.indices(indices);
+    }
 }
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateResponse.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateResponse.java
index 027fff3d79b44..9cb6ac127786a 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateResponse.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/SearchTemplateResponse.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -103,11 +103,11 @@ public static SearchTemplateResponse fromXContent(XContentParser parser) throws
 
         if (contentAsMap.containsKey(TEMPLATE_OUTPUT_FIELD.getPreferredName())) {
             Object source = contentAsMap.get(TEMPLATE_OUTPUT_FIELD.getPreferredName());
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON).value(source);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON).value(source);
             searchTemplateResponse.setSource(BytesReference.bytes(builder));
         } else {
-            XContentType contentType = parser.contentType();
-            XContentBuilder builder = XContentFactory.contentBuilder(contentType).map(contentAsMap);
+            MediaType contentType = parser.contentType();
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(contentType).map(contentAsMap);
             XContentParser searchResponseParser = contentType.xContent()
                 .createParser(parser.getXContentRegistry(), parser.getDeprecationHandler(), BytesReference.bytes(builder).streamInput());
 
@@ -125,7 +125,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.startObject();
             // we can assume the template is always json as we convert it before compiling it
             try (InputStream stream = source.streamInput()) {
-                builder.rawField(TEMPLATE_OUTPUT_FIELD.getPreferredName(), stream, XContentType.JSON);
+                builder.rawField(TEMPLATE_OUTPUT_FIELD.getPreferredName(), stream, MediaTypeRegistry.JSON);
             }
             builder.endObject();
         }
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportMultiSearchTemplateAction.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportMultiSearchTemplateAction.java
index 8ebc5ace8d58f..b17b48ec1cbf8 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportMultiSearchTemplateAction.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportMultiSearchTemplateAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchRequest;
@@ -40,7 +39,8 @@
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
diff --git a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportSearchTemplateAction.java b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportSearchTemplateAction.java
index 4e83f733d84b3..6e8b9d059b583 100644
--- a/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportSearchTemplateAction.java
+++ b/modules/lang-mustache/src/main/java/org/opensearch/script/mustache/TransportSearchTemplateAction.java
@@ -32,19 +32,18 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptService;
@@ -132,7 +131,7 @@ static SearchRequest convert(
         }
 
         try (
-            XContentParser parser = XContentFactory.xContent(XContentType.JSON)
+            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                 .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, source)
         ) {
             SearchSourceBuilder builder = SearchSourceBuilder.searchSource();
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateRequestTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateRequestTests.java
index 1a663dcb18235..7499d86f70b2b 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateRequestTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateRequestTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.script.mustache;
 
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.Scroll;
@@ -56,7 +56,7 @@ public class MultiSearchTemplateRequestTests extends OpenSearchTestCase {
 
     public void testParseRequest() throws Exception {
         byte[] data = StreamsUtils.copyToBytesFromClasspath("/org/opensearch/script/mustache/simple-msearch-template.json");
-        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data), XContentType.JSON)
+        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data), MediaTypeRegistry.JSON)
             .build();
 
         MultiSearchTemplateRequest request = RestMultiSearchTemplateAction.parseRequest(restRequest, true);
@@ -92,8 +92,10 @@ public void testParseRequest() throws Exception {
     public void testParseWithCarriageReturn() throws Exception {
         final String content = "{\"index\":[\"test0\", \"test1\"], \"request_cache\": true}\r\n"
             + "{\"source\": {\"query\" : {\"match_{{template}}\" :{}}}, \"params\": {\"template\": \"all\" } }\r\n";
-        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(content), XContentType.JSON)
-            .build();
+        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
+            new BytesArray(content),
+            MediaTypeRegistry.JSON
+        ).build();
 
         MultiSearchTemplateRequest request = RestMultiSearchTemplateAction.parseRequest(restRequest, true);
 
@@ -144,8 +146,10 @@ public void testMultiSearchTemplateToJson() throws Exception {
         String serialized = toJsonString(multiSearchTemplateRequest);
 
         // Deserialize the request
-        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(serialized), XContentType.JSON)
-            .build();
+        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
+            new BytesArray(serialized),
+            MediaTypeRegistry.JSON
+        ).build();
         MultiSearchTemplateRequest deser = RestMultiSearchTemplateAction.parseRequest(restRequest, true);
 
         // For object equality purposes need to set the search requests' source to non-null
@@ -163,7 +167,7 @@ public void testMultiSearchTemplateToJson() throws Exception {
     }
 
     protected String toJsonString(MultiSearchTemplateRequest multiSearchTemplateRequest) throws IOException {
-        byte[] bytes = MultiSearchTemplateRequest.writeMultiLineFormat(multiSearchTemplateRequest, XContentType.JSON.xContent());
+        byte[] bytes = MultiSearchTemplateRequest.writeMultiLineFormat(multiSearchTemplateRequest, MediaTypeRegistry.JSON.xContent());
         return new String(bytes, StandardCharsets.UTF_8);
     }
 
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateResponseTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateResponseTests.java
index 4aee84beb4db1..aeb7cdc2c6a28 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateResponseTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MultiSearchTemplateResponseTests.java
@@ -34,9 +34,9 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.test.AbstractXContentTestCase;
 
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheScriptEngineTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheScriptEngineTests.java
index 326990d804b4f..9e97863306148 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheScriptEngineTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheScriptEngineTests.java
@@ -33,10 +33,10 @@
 
 import com.github.mustachejava.MustacheFactory;
 
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.script.TemplateScript;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
+import org.opensearch.script.TemplateScript;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheTests.java
index a74fc48423553..93e4c2ce928b0 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/MustacheTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.ScriptEngine;
 import org.opensearch.script.ScriptException;
 import org.opensearch.script.TemplateScript;
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestTests.java
index 6c8e91d8c4d17..72443d1323b44 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.RandomSearchRequestGenerator;
 import org.opensearch.search.builder.SearchSourceBuilder;
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestXContentTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestXContentTests.java
index 4783b8d3f890e..08d7841306161 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestXContentTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateRequestXContentTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.script.mustache;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.AbstractXContentTestCase;
 
@@ -101,7 +101,7 @@ public void testToXContentWithInlineTemplate() throws IOException {
         request.setScriptParams(scriptParams);
 
         XContentType contentType = randomFrom(XContentType.values());
-        XContentBuilder expectedRequest = XContentFactory.contentBuilder(contentType)
+        XContentBuilder expectedRequest = MediaTypeRegistry.contentBuilder(contentType)
             .startObject()
             .field("source", "{\"query\": { \"match\" : { \"{{my_field}}\" : \"{{my_value}}\" } } }")
             .startObject("params")
@@ -112,7 +112,7 @@ public void testToXContentWithInlineTemplate() throws IOException {
             .field("profile", true)
             .endObject();
 
-        XContentBuilder actualRequest = XContentFactory.contentBuilder(contentType);
+        XContentBuilder actualRequest = MediaTypeRegistry.contentBuilder(contentType);
         request.toXContent(actualRequest, ToXContent.EMPTY_PARAMS);
 
         assertToXContentEquivalent(BytesReference.bytes(expectedRequest), BytesReference.bytes(actualRequest), contentType);
@@ -131,7 +131,7 @@ public void testToXContentWithStoredTemplate() throws IOException {
         request.setScriptParams(params);
 
         XContentType contentType = randomFrom(XContentType.values());
-        XContentBuilder expectedRequest = XContentFactory.contentBuilder(contentType)
+        XContentBuilder expectedRequest = MediaTypeRegistry.contentBuilder(contentType)
             .startObject()
             .field("id", "match_template")
             .startObject("params")
@@ -142,7 +142,7 @@ public void testToXContentWithStoredTemplate() throws IOException {
             .field("profile", false)
             .endObject();
 
-        XContentBuilder actualRequest = XContentFactory.contentBuilder(contentType);
+        XContentBuilder actualRequest = MediaTypeRegistry.contentBuilder(contentType);
         request.toXContent(actualRequest, ToXContent.EMPTY_PARAMS);
 
         assertToXContentEquivalent(BytesReference.bytes(expectedRequest), BytesReference.bytes(actualRequest), contentType);
diff --git a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateResponseTests.java b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateResponseTests.java
index 0a2bb247e3c1a..c2685e45ecb6b 100644
--- a/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateResponseTests.java
+++ b/modules/lang-mustache/src/test/java/org/opensearch/script/mustache/SearchTemplateResponseTests.java
@@ -35,12 +35,13 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.internal.InternalSearchResponse;
@@ -129,7 +130,7 @@ protected void assertEqualInstances(SearchTemplateResponse expectedInstance, Sea
         assertEquals(expectedSource == null, newSource == null);
         if (expectedSource != null) {
             try {
-                assertToXContentEquivalent(expectedSource, newSource, XContentType.JSON);
+                assertToXContentEquivalent(expectedSource, newSource, MediaTypeRegistry.JSON);
             } catch (IOException e) {
                 throw new RuntimeException(e);
             }
@@ -164,7 +165,7 @@ public void testSourceToXContent() throws IOException {
         response.setSource(BytesReference.bytes(source));
 
         XContentType contentType = randomFrom(XContentType.values());
-        XContentBuilder expectedResponse = XContentFactory.contentBuilder(contentType)
+        XContentBuilder expectedResponse = MediaTypeRegistry.contentBuilder(contentType)
             .startObject()
             .startObject("template_output")
             .startObject("query")
@@ -175,7 +176,7 @@ public void testSourceToXContent() throws IOException {
             .endObject()
             .endObject();
 
-        XContentBuilder actualResponse = XContentFactory.contentBuilder(contentType);
+        XContentBuilder actualResponse = MediaTypeRegistry.contentBuilder(contentType);
         response.toXContent(actualResponse, ToXContent.EMPTY_PARAMS);
 
         assertToXContentEquivalent(BytesReference.bytes(expectedResponse), BytesReference.bytes(actualResponse), contentType);
@@ -210,7 +211,7 @@ public void testSearchResponseToXContent() throws IOException {
         response.setResponse(searchResponse);
 
         XContentType contentType = randomFrom(XContentType.values());
-        XContentBuilder expectedResponse = XContentFactory.contentBuilder(contentType)
+        XContentBuilder expectedResponse = MediaTypeRegistry.contentBuilder(contentType)
             .startObject()
             .field("took", 0)
             .field("timed_out", false)
@@ -235,7 +236,7 @@ public void testSearchResponseToXContent() throws IOException {
             .endObject()
             .endObject();
 
-        XContentBuilder actualResponse = XContentFactory.contentBuilder(contentType);
+        XContentBuilder actualResponse = MediaTypeRegistry.contentBuilder(contentType);
         response.toXContent(actualResponse, ToXContent.EMPTY_PARAMS);
 
         assertToXContentEquivalent(BytesReference.bytes(expectedResponse), BytesReference.bytes(actualResponse), contentType);
diff --git a/modules/lang-mustache/src/yamlRestTest/resources/rest-api-spec/test/lang_mustache/10_basic.yml b/modules/lang-mustache/src/yamlRestTest/resources/rest-api-spec/test/lang_mustache/10_basic.yml
index 0e853d6273142..5fc67b766cb1a 100644
--- a/modules/lang-mustache/src/yamlRestTest/resources/rest-api-spec/test/lang_mustache/10_basic.yml
+++ b/modules/lang-mustache/src/yamlRestTest/resources/rest-api-spec/test/lang_mustache/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: lang-mustache } }
+    - contains:  { nodes.$cluster_manager.modules: { name: lang-mustache } }
diff --git a/modules/lang-painless/build.gradle b/modules/lang-painless/build.gradle
index 7f37b5e76d904..669a5363d6294 100644
--- a/modules/lang-painless/build.gradle
+++ b/modules/lang-painless/build.gradle
@@ -29,14 +29,22 @@
  */
 
 import org.opensearch.gradle.testclusters.DefaultTestClustersTask;
+import com.github.jengelman.gradle.plugins.shadow.ShadowBasePlugin
+
 apply plugin: 'opensearch.validate-rest-spec'
 apply plugin: 'opensearch.yaml-rest-test'
+apply plugin: 'com.github.johnrengelman.shadow'
 
 opensearchplugin {
   description 'An easy, safe and fast scripting language for OpenSearch'
   classname 'org.opensearch.painless.PainlessPlugin'
 }
 
+ext {
+  // Do not fail on `javadoc` warning (ANTLR generated code)
+  failOnJavadocWarning = false
+}
+
 testClusters.all {
   module ':modules:mapper-extras'
   systemProperty 'opensearch.scripting.update.ctx_in_params', 'false'
@@ -45,15 +53,39 @@ testClusters.all {
 }
 
 dependencies {
-  api 'org.antlr:antlr4-runtime:4.9.3'
-  api 'org.ow2.asm:asm-util:9.2'
-  api 'org.ow2.asm:asm-tree:7.2'
-  api 'org.ow2.asm:asm-commons:9.2'
-  api 'org.ow2.asm:asm-analysis:7.2'
-  api 'org.ow2.asm:asm:9.2'
+  api "org.antlr:antlr4-runtime:${versions.antlr4}"
+  api "org.ow2.asm:asm-util:${versions.asm}"
+  api "org.ow2.asm:asm-tree:${versions.asm}"
+  api "org.ow2.asm:asm-commons:${versions.asm}"
+  api "org.ow2.asm:asm-analysis:${versions.asm}"
+  api "org.ow2.asm:asm:${versions.asm}"
   api project('spi')
 }
 
+test {
+  doFirst {
+    test.classpath -= project.files(project.tasks.named('shadowJar'))
+    test.classpath -= project.configurations.getByName(ShadowBasePlugin.CONFIGURATION_NAME)
+    test.classpath += project.extensions.getByType(SourceSetContainer).getByName(SourceSet.MAIN_SOURCE_SET_NAME).runtimeClasspath
+  }
+}
+
+shadowJar {
+  archiveClassifier.set('')
+  relocate 'org.objectweb', 'org.opensearch.repackage.org.objectweb'
+  dependencies {
+    include(dependency("org.ow2.asm:asm:${versions.asm}"))
+    include(dependency("org.ow2.asm:asm-util:${versions.asm}"))
+    include(dependency("org.ow2.asm:asm-tree:${versions.asm}"))
+    include(dependency("org.ow2.asm:asm-commons:${versions.asm}"))
+    include(dependency("org.ow2.asm:asm-analysis:${versions.asm}"))
+  }
+}
+
+tasks.validateNebulaPom.dependsOn tasks.generatePomFileForShadowPublication
+tasks.validateShadowPom.dependsOn tasks.generatePomFileForNebulaPublication
+tasks.withType(AbstractPublishToMaven)*.dependsOn "generatePomFileForShadowPublication", "generatePomFileForNebulaPublication"
+
 tasks.named("dependencyLicenses").configure {
   mapping from: /asm-.*/, to: 'asm'
 }
@@ -76,7 +108,7 @@ tasks.register("apiJavadoc", Javadoc) {
   source = sourceSets.main.allJava
   classpath = sourceSets.main.runtimeClasspath
   include '**/org/opensearch/painless/api/'
-  destinationDir = new File(docsDir, 'apiJavadoc')
+  destinationDir = new File(file(java.docsDir), 'apiJavadoc')
 }
 
 tasks.register("apiJavadocJar", Jar) {
@@ -111,7 +143,7 @@ tasks.register("generateContextDoc", DefaultTestClustersTask) {
   useCluster testClusters.generateContextCluster
   doFirst {
     project.javaexec {
-      main = 'org.opensearch.painless.ContextDocGenerator'
+      mainClass = 'org.opensearch.painless.ContextDocGenerator'
       classpath = sourceSets.doc.runtimeClasspath
       systemProperty "cluster.uri", "${-> testClusters.generateContextCluster.singleNode().getAllHttpSocketURI().get(0)}"
     }.assertNormalExitValue()
@@ -127,7 +159,7 @@ configurations {
 }
 
 dependencies {
-  regenerate 'org.antlr:antlr4:4.5.3'
+  regenerate "org.antlr:antlr4:${versions.antlr4}"
 }
 
 String grammarPath = 'src/main/antlr'
@@ -144,7 +176,7 @@ tasks.register("cleanGenerated", Delete) {
 
 tasks.register("regenLexer", JavaExec) {
   dependsOn "cleanGenerated"
-  main = 'org.antlr.v4.Tool'
+  mainClass = 'org.antlr.v4.Tool'
   classpath = configurations.regenerate
   systemProperty 'file.encoding', 'UTF-8'
   systemProperty 'user.language', 'en'
@@ -158,7 +190,7 @@ tasks.register("regenLexer", JavaExec) {
 
 tasks.register("regenParser", JavaExec) {
   dependsOn "regenLexer"
-  main = 'org.antlr.v4.Tool'
+  mainClass = 'org.antlr.v4.Tool'
   classpath = configurations.regenerate
   systemProperty 'file.encoding', 'UTF-8'
   systemProperty 'user.language', 'en'
diff --git a/modules/lang-painless/licenses/antlr4-runtime-4.11.1.jar.sha1 b/modules/lang-painless/licenses/antlr4-runtime-4.11.1.jar.sha1
new file mode 100644
index 0000000000000..f1b328a6de624
--- /dev/null
+++ b/modules/lang-painless/licenses/antlr4-runtime-4.11.1.jar.sha1
@@ -0,0 +1 @@
+069214c1de1960040729702eb58deac8827135e7
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/antlr4-runtime-4.9.3.jar.sha1 b/modules/lang-painless/licenses/antlr4-runtime-4.9.3.jar.sha1
deleted file mode 100644
index 13a2367439ede..0000000000000
--- a/modules/lang-painless/licenses/antlr4-runtime-4.9.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-81befc16ebedb8b8aea3e4c0835dd5ca7e8523a8
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-9.2.jar.sha1 b/modules/lang-painless/licenses/asm-9.2.jar.sha1
deleted file mode 100644
index 28f456d3cbcb2..0000000000000
--- a/modules/lang-painless/licenses/asm-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-81a03f76019c67362299c40e0ba13405f5467bff
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-9.6.jar.sha1 b/modules/lang-painless/licenses/asm-9.6.jar.sha1
new file mode 100644
index 0000000000000..2d9e6a9d3cfd6
--- /dev/null
+++ b/modules/lang-painless/licenses/asm-9.6.jar.sha1
@@ -0,0 +1 @@
+aa205cf0a06dbd8e04ece91c0b37c3f5d567546a
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-analysis-7.2.jar.sha1 b/modules/lang-painless/licenses/asm-analysis-7.2.jar.sha1
deleted file mode 100644
index 849b5e0bfa671..0000000000000
--- a/modules/lang-painless/licenses/asm-analysis-7.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-b6e6abe057f23630113f4167c34bda7086691258
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-analysis-9.6.jar.sha1 b/modules/lang-painless/licenses/asm-analysis-9.6.jar.sha1
new file mode 100644
index 0000000000000..fa42ea1198165
--- /dev/null
+++ b/modules/lang-painless/licenses/asm-analysis-9.6.jar.sha1
@@ -0,0 +1 @@
+9ce6c7b174bd997fc2552dff47964546bd7a5ec3
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-commons-9.2.jar.sha1 b/modules/lang-painless/licenses/asm-commons-9.2.jar.sha1
deleted file mode 100644
index 7beb3d29afe86..0000000000000
--- a/modules/lang-painless/licenses/asm-commons-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f4d7f0fc9054386f2893b602454d48e07d4fbead
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-commons-9.6.jar.sha1 b/modules/lang-painless/licenses/asm-commons-9.6.jar.sha1
new file mode 100644
index 0000000000000..a0814f495771f
--- /dev/null
+++ b/modules/lang-painless/licenses/asm-commons-9.6.jar.sha1
@@ -0,0 +1 @@
+f1a9e5508eff490744144565c47326c8648be309
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-tree-7.2.jar.sha1 b/modules/lang-painless/licenses/asm-tree-7.2.jar.sha1
deleted file mode 100644
index 986a1c55f5e8f..0000000000000
--- a/modules/lang-painless/licenses/asm-tree-7.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3a23cc36edaf8fc5a89cb100182758ccb5991487
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-tree-9.6.jar.sha1 b/modules/lang-painless/licenses/asm-tree-9.6.jar.sha1
new file mode 100644
index 0000000000000..101eb03b4b736
--- /dev/null
+++ b/modules/lang-painless/licenses/asm-tree-9.6.jar.sha1
@@ -0,0 +1 @@
+c0cdda9d211e965d2a4448aa3fd86110f2f8c2de
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-util-9.2.jar.sha1 b/modules/lang-painless/licenses/asm-util-9.2.jar.sha1
deleted file mode 100644
index 5cb89aa115f30..0000000000000
--- a/modules/lang-painless/licenses/asm-util-9.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-fbc178fc5ba3dab50fd7e8a5317b8b647c8e8946
\ No newline at end of file
diff --git a/modules/lang-painless/licenses/asm-util-9.6.jar.sha1 b/modules/lang-painless/licenses/asm-util-9.6.jar.sha1
new file mode 100644
index 0000000000000..1f42ac62dc69c
--- /dev/null
+++ b/modules/lang-painless/licenses/asm-util-9.6.jar.sha1
@@ -0,0 +1 @@
+f77caf84eb93786a749b2baa40865b9613e3eaee
\ No newline at end of file
diff --git a/modules/lang-painless/spi/build.gradle b/modules/lang-painless/spi/build.gradle
index 7811ee0e41dd8..59a77870b4987 100644
--- a/modules/lang-painless/spi/build.gradle
+++ b/modules/lang-painless/spi/build.gradle
@@ -31,8 +31,10 @@
 apply plugin: 'opensearch.build'
 apply plugin: 'opensearch.publish'
 
-group = 'org.opensearch.plugin'
-archivesBaseName = 'opensearch-scripting-painless-spi'
+base {
+  group = 'org.opensearch.plugin'
+  archivesBaseName = 'opensearch-scripting-painless-spi'
+}
 
 dependencies {
   api project(":server")
diff --git a/modules/lang-painless/src/doc/java/org/opensearch/painless/ContextDocGenerator.java b/modules/lang-painless/src/doc/java/org/opensearch/painless/ContextDocGenerator.java
index cc3fcaa828e55..c31f279d712f5 100644
--- a/modules/lang-painless/src/doc/java/org/opensearch/painless/ContextDocGenerator.java
+++ b/modules/lang-painless/src/doc/java/org/opensearch/painless/ContextDocGenerator.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.action.PainlessContextClassBindingInfo;
 import org.opensearch.painless.action.PainlessContextClassInfo;
 import org.opensearch.painless.action.PainlessContextConstructorInfo;
diff --git a/modules/lang-painless/src/main/antlr/PainlessLexer.g4 b/modules/lang-painless/src/main/antlr/PainlessLexer.g4
index 7dd168833e347..21b03b85d8edd 100644
--- a/modules/lang-painless/src/main/antlr/PainlessLexer.g4
+++ b/modules/lang-painless/src/main/antlr/PainlessLexer.g4
@@ -124,4 +124,4 @@ ID: [_a-zA-Z] [_a-zA-Z0-9]*;
 mode AFTER_DOT;
 
 DOTINTEGER: ( '0' | [1-9] [0-9]* ) -> mode(DEFAULT_MODE);
-DOTID: [_a-zA-Z] [_a-zA-Z0-9]*     -> mode(DEFAULT_MODE);
\ No newline at end of file
+DOTID: [_a-zA-Z] [_a-zA-Z0-9]*     -> mode(DEFAULT_MODE);
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/AnalyzerCaster.java b/modules/lang-painless/src/main/java/org/opensearch/painless/AnalyzerCaster.java
index e375ff14db67e..d830ef2ab6290 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/AnalyzerCaster.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/AnalyzerCaster.java
@@ -412,7 +412,7 @@ public static PainlessCast getLegalCast(Location location, Class<?> actual, Clas
             }
         }
 
-        if (actual == def.class
+        if ((actual == def.class && expected != void.class)
             || (actual != void.class && expected == def.class)
             || expected.isAssignableFrom(actual)
             || (actual.isAssignableFrom(expected) && explicit)) {
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/Compiler.java b/modules/lang-painless/src/main/java/org/opensearch/painless/Compiler.java
index eca931d87b68c..1f57c5cbd1149 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/Compiler.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/Compiler.java
@@ -212,8 +212,9 @@ private static void addFactoryMethod(Map<String, Class<?>> additionalClasses, Cl
         }
 
         additionalClasses.put(factoryClass.getName(), factoryClass);
-        for (int i = 0; i < factoryMethod.getParameterTypes().length; ++i) {
-            Class<?> parameterClazz = factoryMethod.getParameterTypes()[i];
+        final Class<?>[] parameterTypes = factoryMethod.getParameterTypes();
+        for (int i = 0; i < parameterTypes.length; ++i) {
+            Class<?> parameterClazz = parameterTypes[i];
             additionalClasses.put(parameterClazz.getName(), parameterClazz);
         }
     }
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessPlugin.java b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessPlugin.java
index 09a23c15f346d..aa4081dc70ba6 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessPlugin.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessPlugin.java
@@ -32,20 +32,20 @@
 
 package org.opensearch.painless;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.painless.action.PainlessContextAction;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessScriptEngine.java b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessScriptEngine.java
index 1663185ae7c4e..4555ce5cb1ed0 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessScriptEngine.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessScriptEngine.java
@@ -195,11 +195,12 @@ private <T> Type generateStatefulFactory(Loader loader, ScriptContext<T> context
             }
         }
 
-        for (int count = 0; count < newFactory.getParameterTypes().length; ++count) {
+        final Class<?>[] parameterTypes = newFactory.getParameterTypes();
+        for (int count = 0; count < parameterTypes.length; ++count) {
             writer.visitField(
                 Opcodes.ACC_PRIVATE | Opcodes.ACC_FINAL,
                 "$arg" + count,
-                Type.getType(newFactory.getParameterTypes()[count]).getDescriptor(),
+                Type.getType(parameterTypes[count]).getDescriptor(),
                 null,
                 null
             ).visitEnd();
@@ -211,7 +212,7 @@ private <T> Type generateStatefulFactory(Loader loader, ScriptContext<T> context
         );
         org.objectweb.asm.commons.Method init = new org.objectweb.asm.commons.Method(
             "<init>",
-            MethodType.methodType(void.class, newFactory.getParameterTypes()).toMethodDescriptorString()
+            MethodType.methodType(void.class, parameterTypes).toMethodDescriptorString()
         );
 
         GeneratorAdapter constructor = new GeneratorAdapter(
@@ -223,10 +224,10 @@ private <T> Type generateStatefulFactory(Loader loader, ScriptContext<T> context
         constructor.loadThis();
         constructor.invokeConstructor(OBJECT_TYPE, base);
 
-        for (int count = 0; count < newFactory.getParameterTypes().length; ++count) {
+        for (int count = 0; count < parameterTypes.length; ++count) {
             constructor.loadThis();
             constructor.loadArg(count);
-            constructor.putField(Type.getType("L" + className + ";"), "$arg" + count, Type.getType(newFactory.getParameterTypes()[count]));
+            constructor.putField(Type.getType("L" + className + ";"), "$arg" + count, Type.getType(parameterTypes[count]));
         }
 
         constructor.returnValue();
@@ -247,7 +248,7 @@ private <T> Type generateStatefulFactory(Loader loader, ScriptContext<T> context
             MethodType.methodType(newInstance.getReturnType(), newInstance.getParameterTypes()).toMethodDescriptorString()
         );
 
-        List<Class<?>> parameters = new ArrayList<>(Arrays.asList(newFactory.getParameterTypes()));
+        List<Class<?>> parameters = new ArrayList<>(Arrays.asList(parameterTypes));
         parameters.addAll(Arrays.asList(newInstance.getParameterTypes()));
 
         org.objectweb.asm.commons.Method constru = new org.objectweb.asm.commons.Method(
@@ -264,9 +265,9 @@ private <T> Type generateStatefulFactory(Loader loader, ScriptContext<T> context
         adapter.newInstance(WriterConstants.CLASS_TYPE);
         adapter.dup();
 
-        for (int count = 0; count < newFactory.getParameterTypes().length; ++count) {
+        for (int count = 0; count < parameterTypes.length; ++count) {
             adapter.loadThis();
-            adapter.getField(Type.getType("L" + className + ";"), "$arg" + count, Type.getType(newFactory.getParameterTypes()[count]));
+            adapter.getField(Type.getType("L" + className + ";"), "$arg" + count, Type.getType(parameterTypes[count]));
         }
 
         adapter.loadArgs();
@@ -334,13 +335,14 @@ private <T> T generateFactory(Loader loader, ScriptContext<T> context, Type clas
             }
         }
 
+        final Class<?>[] parameterTypes = reflect.getParameterTypes();
         org.objectweb.asm.commons.Method instance = new org.objectweb.asm.commons.Method(
             reflect.getName(),
-            MethodType.methodType(reflect.getReturnType(), reflect.getParameterTypes()).toMethodDescriptorString()
+            MethodType.methodType(reflect.getReturnType(), parameterTypes).toMethodDescriptorString()
         );
         org.objectweb.asm.commons.Method constru = new org.objectweb.asm.commons.Method(
             "<init>",
-            MethodType.methodType(void.class, reflect.getParameterTypes()).toMethodDescriptorString()
+            MethodType.methodType(void.class, parameterTypes).toMethodDescriptorString()
         );
 
         GeneratorAdapter adapter = new GeneratorAdapter(
@@ -421,9 +423,7 @@ private <T> T generateFactory(Loader loader, ScriptContext<T> context, Type clas
 
     private void writeNeedsMethods(Class<?> clazz, ClassWriter writer, Set<String> extractedVariables) {
         for (Method method : clazz.getMethods()) {
-            if (method.getName().startsWith("needs")
-                && method.getReturnType().equals(boolean.class)
-                && method.getParameterTypes().length == 0) {
+            if (method.getName().startsWith("needs") && method.getReturnType().equals(boolean.class) && method.getParameterCount() == 0) {
                 String name = method.getName();
                 name = name.substring(5);
                 name = Character.toLowerCase(name.charAt(0)) + name.substring(1);
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/ScriptClassInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/ScriptClassInfo.java
index a9d5a7abbb150..69aa3f157951e 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/ScriptClassInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/ScriptClassInfo.java
@@ -88,7 +88,7 @@ public ScriptClassInfo(PainlessLookup painlessLookup, Class<?> baseClass) {
                             + "] has more than one."
                     );
                 }
-            } else if (m.getName().startsWith("needs") && m.getReturnType() == boolean.class && m.getParameterTypes().length == 0) {
+            } else if (m.getName().startsWith("needs") && m.getReturnType() == boolean.class && m.getParameterCount() == 0) {
                 needsMethods.add(new org.objectweb.asm.commons.Method(m.getName(), NEEDS_PARAMETER_METHOD_TYPE.toMethodDescriptorString()));
             } else if (m.getName().startsWith("get")
                 && m.getName().equals("getClass") == false
@@ -124,7 +124,7 @@ public ScriptClassInfo(PainlessLookup painlessLookup, Class<?> baseClass) {
         FunctionTable.LocalFunction defConverter = null;
         for (java.lang.reflect.Method m : baseClass.getMethods()) {
             if (m.getName().startsWith("convertFrom")
-                && m.getParameterTypes().length == 1
+                && m.getParameterCount() == 1
                 && m.getReturnType() == returnType
                 && Modifier.isStatic(m.getModifiers())) {
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextAction.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextAction.java
index a9333fde6b443..a26cb79a9717d 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextAction.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextAction.java
@@ -32,21 +32,21 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.painless.PainlessScriptEngine;
 import org.opensearch.painless.lookup.PainlessLookup;
 import org.opensearch.rest.BaseRestHandler;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassBindingInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassBindingInfo.java
index 301c1ca369570..0fa5cc5658b6a 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassBindingInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassBindingInfo.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessClassBinding;
 import org.opensearch.painless.lookup.PainlessLookupUtility;
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassInfo.java
index 272b4d9fa16d7..25f63e1c8bdfa 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextClassInfo.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessClass;
 
 import java.io.IOException;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextConstructorInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextConstructorInfo.java
index 9058be6d2c06b..cc1fc7448d134 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextConstructorInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextConstructorInfo.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessConstructor;
 import org.opensearch.painless.lookup.PainlessLookupUtility;
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextFieldInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextFieldInfo.java
index 1cf1f0937b46e..7187f3403795e 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextFieldInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextFieldInfo.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessField;
 import org.opensearch.painless.lookup.PainlessLookupUtility;
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInfo.java
index e82f2299c51b3..e4642b98154a5 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInfo.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessClassBinding;
 import org.opensearch.painless.lookup.PainlessInstanceBinding;
 import org.opensearch.painless.lookup.PainlessLookup;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInstanceBindingInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInstanceBindingInfo.java
index 74637a790da3b..848868f675422 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInstanceBindingInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextInstanceBindingInfo.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessInstanceBinding;
 import org.opensearch.painless.lookup.PainlessLookupUtility;
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextMethodInfo.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextMethodInfo.java
index eaf751ea63188..02061b4543d9f 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextMethodInfo.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessContextMethodInfo.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.painless.lookup.PainlessLookupUtility;
 import org.opensearch.painless.lookup.PainlessMethod;
 
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessExecuteAction.java b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessExecuteAction.java
index be26e69ec22d1..67b298eee7973 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessExecuteAction.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/action/PainlessExecuteAction.java
@@ -45,7 +45,6 @@
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.Directory;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.IndicesOptions;
@@ -58,28 +57,29 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedBiFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -178,7 +178,7 @@ static class ContextSetup implements Writeable, ToXContentObject {
             private final BytesReference document;
             private final QueryBuilder query;
 
-            private XContentType xContentType;
+            private MediaType mediaType;
 
             static ContextSetup parse(XContentParser parser, Void context) throws IOException {
                 ContextSetup contextSetup = PARSER.parse(parser, null);
@@ -195,9 +195,9 @@ static ContextSetup parse(XContentParser parser, Void context) throws IOExceptio
             ContextSetup(StreamInput in) throws IOException {
                 index = in.readOptionalString();
                 document = in.readOptionalBytesReference();
-                String xContentType = in.readOptionalString();
-                if (xContentType != null) {
-                    this.xContentType = XContentType.fromMediaType(xContentType);
+                String mediaType = in.readOptionalString();
+                if (mediaType != null) {
+                    this.mediaType = MediaType.fromMediaType(mediaType);
                 }
                 query = in.readOptionalNamedWriteable(QueryBuilder.class);
             }
@@ -214,12 +214,12 @@ public QueryBuilder getQuery() {
                 return query;
             }
 
-            public XContentType getXContentType() {
-                return xContentType;
+            public MediaType getXContentType() {
+                return mediaType;
             }
 
-            public void setXContentType(XContentType xContentType) {
-                this.xContentType = xContentType;
+            public void setXContentType(MediaType mediaType) {
+                this.mediaType = mediaType;
             }
 
             @Override
@@ -230,19 +230,19 @@ public boolean equals(Object o) {
                 return Objects.equals(index, that.index)
                     && Objects.equals(document, that.document)
                     && Objects.equals(query, that.query)
-                    && Objects.equals(xContentType, that.xContentType);
+                    && Objects.equals(mediaType, that.mediaType);
             }
 
             @Override
             public int hashCode() {
-                return Objects.hash(index, document, query, xContentType);
+                return Objects.hash(index, document, query, mediaType);
             }
 
             @Override
             public void writeTo(StreamOutput out) throws IOException {
                 out.writeOptionalString(index);
                 out.writeOptionalBytesReference(document);
-                out.writeOptionalString(xContentType != null ? xContentType.mediaTypeWithoutParameters() : null);
+                out.writeOptionalString(mediaType != null ? mediaType.mediaTypeWithoutParameters() : null);
                 out.writeOptionalNamedWriteable(query);
             }
 
@@ -257,7 +257,7 @@ public String toString() {
                     + ", query="
                     + query
                     + ", xContentType="
-                    + xContentType
+                    + mediaType
                     + '}';
             }
 
@@ -275,7 +275,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                                 NamedXContentRegistry.EMPTY,
                                 LoggingDeprecationHandler.INSTANCE,
                                 document,
-                                xContentType
+                                mediaType
                             )
                         ) {
                             builder.generator().copyCurrentStructure(parser);
@@ -558,7 +558,11 @@ static Response innerShardOperation(Request request, ScriptService scriptService
             } else if (scriptContext == ScoreScript.CONTEXT) {
                 return prepareRamIndex(request, (context, leafReaderContext) -> {
                     ScoreScript.Factory factory = scriptService.compile(request.script, ScoreScript.CONTEXT);
-                    ScoreScript.LeafFactory leafFactory = factory.newFactory(request.getScript().getParams(), context.lookup());
+                    ScoreScript.LeafFactory leafFactory = factory.newFactory(
+                        request.getScript().getParams(),
+                        context.lookup(),
+                        context.searcher()
+                    );
                     ScoreScript scoreScript = leafFactory.newInstance(leafReaderContext);
                     scoreScript.setDocument(0);
 
@@ -594,8 +598,8 @@ private static Response prepareRamIndex(
                 try (IndexWriter indexWriter = new IndexWriter(directory, new IndexWriterConfig(defaultAnalyzer))) {
                     String index = indexService.index().getName();
                     BytesReference document = request.contextSetup.document;
-                    XContentType xContentType = request.contextSetup.xContentType;
-                    SourceToParse sourceToParse = new SourceToParse(index, "_id", document, xContentType);
+                    MediaType mediaType = request.contextSetup.mediaType;
+                    SourceToParse sourceToParse = new SourceToParse(index, "_id", document, mediaType);
                     ParsedDocument parsedDocument = indexService.mapperService().documentMapper().parse(sourceToParse);
                     indexWriter.addDocuments(parsedDocument.docs());
                     try (IndexReader indexReader = DirectoryReader.open(indexWriter)) {
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/EnhancedPainlessLexer.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/EnhancedPainlessLexer.java
index 805b8a8a45bdc..5cc28e060c7cd 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/EnhancedPainlessLexer.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/EnhancedPainlessLexer.java
@@ -36,6 +36,7 @@
 import org.antlr.v4.runtime.LexerNoViableAltException;
 import org.antlr.v4.runtime.Token;
 import org.antlr.v4.runtime.misc.Interval;
+
 import org.opensearch.painless.Location;
 
 /**
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessLexer.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessLexer.java
index 82b8bc939e910..fb33cf6e2a6f5 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessLexer.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessLexer.java
@@ -33,17 +33,22 @@
 
 package org.opensearch.painless.antlr;
 
-import org.antlr.v4.runtime.Lexer;
 import org.antlr.v4.runtime.CharStream;
-import org.antlr.v4.runtime.*;
-import org.antlr.v4.runtime.atn.*;
+import org.antlr.v4.runtime.Lexer;
+import org.antlr.v4.runtime.RuleContext;
+import org.antlr.v4.runtime.RuntimeMetaData;
+import org.antlr.v4.runtime.Vocabulary;
+import org.antlr.v4.runtime.VocabularyImpl;
+import org.antlr.v4.runtime.atn.ATN;
+import org.antlr.v4.runtime.atn.ATNDeserializer;
+import org.antlr.v4.runtime.atn.LexerATNSimulator;
+import org.antlr.v4.runtime.atn.PredictionContextCache;
 import org.antlr.v4.runtime.dfa.DFA;
-import org.antlr.v4.runtime.misc.*;
 
-@SuppressWarnings({ "all", "warnings", "unchecked", "unused", "cast" })
+@SuppressWarnings({ "all", "warnings", "unchecked", "unused", "cast", "CheckReturnValue" })
 abstract class PainlessLexer extends Lexer {
     static {
-        RuntimeMetaData.checkVersion("4.5.3", RuntimeMetaData.VERSION);
+        RuntimeMetaData.checkVersion("4.11.1", RuntimeMetaData.VERSION);
     }
 
     protected static final DFA[] _decisionToDFA;
@@ -57,266 +62,281 @@ abstract class PainlessLexer extends Lexer {
             68, ALSH = 69, ARSH = 70, AUSH = 71, OCTAL = 72, HEX = 73, INTEGER = 74, DECIMAL = 75, STRING = 76, REGEX = 77, TRUE = 78,
         FALSE = 79, NULL = 80, PRIMITIVE = 81, DEF = 82, ID = 83, DOTINTEGER = 84, DOTID = 85;
     public static final int AFTER_DOT = 1;
+    public static String[] channelNames = { "DEFAULT_TOKEN_CHANNEL", "HIDDEN" };
+
     public static String[] modeNames = { "DEFAULT_MODE", "AFTER_DOT" };
 
-    public static final String[] ruleNames = {
-        "WS",
-        "COMMENT",
-        "LBRACK",
-        "RBRACK",
-        "LBRACE",
-        "RBRACE",
-        "LP",
-        "RP",
-        "DOT",
-        "NSDOT",
-        "COMMA",
-        "SEMICOLON",
-        "IF",
-        "IN",
-        "ELSE",
-        "WHILE",
-        "DO",
-        "FOR",
-        "CONTINUE",
-        "BREAK",
-        "RETURN",
-        "NEW",
-        "TRY",
-        "CATCH",
-        "THROW",
-        "THIS",
-        "INSTANCEOF",
-        "BOOLNOT",
-        "BWNOT",
-        "MUL",
-        "DIV",
-        "REM",
-        "ADD",
-        "SUB",
-        "LSH",
-        "RSH",
-        "USH",
-        "LT",
-        "LTE",
-        "GT",
-        "GTE",
-        "EQ",
-        "EQR",
-        "NE",
-        "NER",
-        "BWAND",
-        "XOR",
-        "BWOR",
-        "BOOLAND",
-        "BOOLOR",
-        "COND",
-        "COLON",
-        "ELVIS",
-        "REF",
-        "ARROW",
-        "FIND",
-        "MATCH",
-        "INCR",
-        "DECR",
-        "ASSIGN",
-        "AADD",
-        "ASUB",
-        "AMUL",
-        "ADIV",
-        "AREM",
-        "AAND",
-        "AXOR",
-        "AOR",
-        "ALSH",
-        "ARSH",
-        "AUSH",
-        "OCTAL",
-        "HEX",
-        "INTEGER",
-        "DECIMAL",
-        "STRING",
-        "REGEX",
-        "TRUE",
-        "FALSE",
-        "NULL",
-        "PRIMITIVE",
-        "DEF",
-        "ID",
-        "DOTINTEGER",
-        "DOTID" };
+    private static String[] makeRuleNames() {
+        return new String[] {
+            "WS",
+            "COMMENT",
+            "LBRACK",
+            "RBRACK",
+            "LBRACE",
+            "RBRACE",
+            "LP",
+            "RP",
+            "DOT",
+            "NSDOT",
+            "COMMA",
+            "SEMICOLON",
+            "IF",
+            "IN",
+            "ELSE",
+            "WHILE",
+            "DO",
+            "FOR",
+            "CONTINUE",
+            "BREAK",
+            "RETURN",
+            "NEW",
+            "TRY",
+            "CATCH",
+            "THROW",
+            "THIS",
+            "INSTANCEOF",
+            "BOOLNOT",
+            "BWNOT",
+            "MUL",
+            "DIV",
+            "REM",
+            "ADD",
+            "SUB",
+            "LSH",
+            "RSH",
+            "USH",
+            "LT",
+            "LTE",
+            "GT",
+            "GTE",
+            "EQ",
+            "EQR",
+            "NE",
+            "NER",
+            "BWAND",
+            "XOR",
+            "BWOR",
+            "BOOLAND",
+            "BOOLOR",
+            "COND",
+            "COLON",
+            "ELVIS",
+            "REF",
+            "ARROW",
+            "FIND",
+            "MATCH",
+            "INCR",
+            "DECR",
+            "ASSIGN",
+            "AADD",
+            "ASUB",
+            "AMUL",
+            "ADIV",
+            "AREM",
+            "AAND",
+            "AXOR",
+            "AOR",
+            "ALSH",
+            "ARSH",
+            "AUSH",
+            "OCTAL",
+            "HEX",
+            "INTEGER",
+            "DECIMAL",
+            "STRING",
+            "REGEX",
+            "TRUE",
+            "FALSE",
+            "NULL",
+            "PRIMITIVE",
+            "DEF",
+            "ID",
+            "DOTINTEGER",
+            "DOTID" };
+    }
+
+    public static final String[] ruleNames = makeRuleNames();
+
+    private static String[] makeLiteralNames() {
+        return new String[] {
+            null,
+            null,
+            null,
+            "'{'",
+            "'}'",
+            "'['",
+            "']'",
+            "'('",
+            "')'",
+            "'.'",
+            "'?.'",
+            "','",
+            "';'",
+            "'if'",
+            "'in'",
+            "'else'",
+            "'while'",
+            "'do'",
+            "'for'",
+            "'continue'",
+            "'break'",
+            "'return'",
+            "'new'",
+            "'try'",
+            "'catch'",
+            "'throw'",
+            "'this'",
+            "'instanceof'",
+            "'!'",
+            "'~'",
+            "'*'",
+            "'/'",
+            "'%'",
+            "'+'",
+            "'-'",
+            "'<<'",
+            "'>>'",
+            "'>>>'",
+            "'<'",
+            "'<='",
+            "'>'",
+            "'>='",
+            "'=='",
+            "'==='",
+            "'!='",
+            "'!=='",
+            "'&'",
+            "'^'",
+            "'|'",
+            "'&&'",
+            "'||'",
+            "'?'",
+            "':'",
+            "'?:'",
+            "'::'",
+            "'->'",
+            "'=~'",
+            "'==~'",
+            "'++'",
+            "'--'",
+            "'='",
+            "'+='",
+            "'-='",
+            "'*='",
+            "'/='",
+            "'%='",
+            "'&='",
+            "'^='",
+            "'|='",
+            "'<<='",
+            "'>>='",
+            "'>>>='",
+            null,
+            null,
+            null,
+            null,
+            null,
+            null,
+            "'true'",
+            "'false'",
+            "'null'",
+            null,
+            "'def'" };
+    }
 
-    private static final String[] _LITERAL_NAMES = {
-        null,
-        null,
-        null,
-        "'{'",
-        "'}'",
-        "'['",
-        "']'",
-        "'('",
-        "')'",
-        "'.'",
-        "'?.'",
-        "','",
-        "';'",
-        "'if'",
-        "'in'",
-        "'else'",
-        "'while'",
-        "'do'",
-        "'for'",
-        "'continue'",
-        "'break'",
-        "'return'",
-        "'new'",
-        "'try'",
-        "'catch'",
-        "'throw'",
-        "'this'",
-        "'instanceof'",
-        "'!'",
-        "'~'",
-        "'*'",
-        "'/'",
-        "'%'",
-        "'+'",
-        "'-'",
-        "'<<'",
-        "'>>'",
-        "'>>>'",
-        "'<'",
-        "'<='",
-        "'>'",
-        "'>='",
-        "'=='",
-        "'==='",
-        "'!='",
-        "'!=='",
-        "'&'",
-        "'^'",
-        "'|'",
-        "'&&'",
-        "'||'",
-        "'?'",
-        "':'",
-        "'?:'",
-        "'::'",
-        "'->'",
-        "'=~'",
-        "'==~'",
-        "'++'",
-        "'--'",
-        "'='",
-        "'+='",
-        "'-='",
-        "'*='",
-        "'/='",
-        "'%='",
-        "'&='",
-        "'^='",
-        "'|='",
-        "'<<='",
-        "'>>='",
-        "'>>>='",
-        null,
-        null,
-        null,
-        null,
-        null,
-        null,
-        "'true'",
-        "'false'",
-        "'null'",
-        null,
-        "'def'" };
-    private static final String[] _SYMBOLIC_NAMES = {
-        null,
-        "WS",
-        "COMMENT",
-        "LBRACK",
-        "RBRACK",
-        "LBRACE",
-        "RBRACE",
-        "LP",
-        "RP",
-        "DOT",
-        "NSDOT",
-        "COMMA",
-        "SEMICOLON",
-        "IF",
-        "IN",
-        "ELSE",
-        "WHILE",
-        "DO",
-        "FOR",
-        "CONTINUE",
-        "BREAK",
-        "RETURN",
-        "NEW",
-        "TRY",
-        "CATCH",
-        "THROW",
-        "THIS",
-        "INSTANCEOF",
-        "BOOLNOT",
-        "BWNOT",
-        "MUL",
-        "DIV",
-        "REM",
-        "ADD",
-        "SUB",
-        "LSH",
-        "RSH",
-        "USH",
-        "LT",
-        "LTE",
-        "GT",
-        "GTE",
-        "EQ",
-        "EQR",
-        "NE",
-        "NER",
-        "BWAND",
-        "XOR",
-        "BWOR",
-        "BOOLAND",
-        "BOOLOR",
-        "COND",
-        "COLON",
-        "ELVIS",
-        "REF",
-        "ARROW",
-        "FIND",
-        "MATCH",
-        "INCR",
-        "DECR",
-        "ASSIGN",
-        "AADD",
-        "ASUB",
-        "AMUL",
-        "ADIV",
-        "AREM",
-        "AAND",
-        "AXOR",
-        "AOR",
-        "ALSH",
-        "ARSH",
-        "AUSH",
-        "OCTAL",
-        "HEX",
-        "INTEGER",
-        "DECIMAL",
-        "STRING",
-        "REGEX",
-        "TRUE",
-        "FALSE",
-        "NULL",
-        "PRIMITIVE",
-        "DEF",
-        "ID",
-        "DOTINTEGER",
-        "DOTID" };
+    private static final String[] _LITERAL_NAMES = makeLiteralNames();
+
+    private static String[] makeSymbolicNames() {
+        return new String[] {
+            null,
+            "WS",
+            "COMMENT",
+            "LBRACK",
+            "RBRACK",
+            "LBRACE",
+            "RBRACE",
+            "LP",
+            "RP",
+            "DOT",
+            "NSDOT",
+            "COMMA",
+            "SEMICOLON",
+            "IF",
+            "IN",
+            "ELSE",
+            "WHILE",
+            "DO",
+            "FOR",
+            "CONTINUE",
+            "BREAK",
+            "RETURN",
+            "NEW",
+            "TRY",
+            "CATCH",
+            "THROW",
+            "THIS",
+            "INSTANCEOF",
+            "BOOLNOT",
+            "BWNOT",
+            "MUL",
+            "DIV",
+            "REM",
+            "ADD",
+            "SUB",
+            "LSH",
+            "RSH",
+            "USH",
+            "LT",
+            "LTE",
+            "GT",
+            "GTE",
+            "EQ",
+            "EQR",
+            "NE",
+            "NER",
+            "BWAND",
+            "XOR",
+            "BWOR",
+            "BOOLAND",
+            "BOOLOR",
+            "COND",
+            "COLON",
+            "ELVIS",
+            "REF",
+            "ARROW",
+            "FIND",
+            "MATCH",
+            "INCR",
+            "DECR",
+            "ASSIGN",
+            "AADD",
+            "ASUB",
+            "AMUL",
+            "ADIV",
+            "AREM",
+            "AAND",
+            "AXOR",
+            "AOR",
+            "ALSH",
+            "ARSH",
+            "AUSH",
+            "OCTAL",
+            "HEX",
+            "INTEGER",
+            "DECIMAL",
+            "STRING",
+            "REGEX",
+            "TRUE",
+            "FALSE",
+            "NULL",
+            "PRIMITIVE",
+            "DEF",
+            "ID",
+            "DOTINTEGER",
+            "DOTID" };
+    }
+
+    private static final String[] _SYMBOLIC_NAMES = makeSymbolicNames();
     public static final Vocabulary VOCABULARY = new VocabularyImpl(_LITERAL_NAMES, _SYMBOLIC_NAMES);
 
     /**
@@ -373,6 +393,11 @@ public String getSerializedATN() {
         return _serializedATN;
     }
 
+    @Override
+    public String[] getChannelNames() {
+        return channelNames;
+    }
+
     @Override
     public String[] getModeNames() {
         return modeNames;
@@ -410,228 +435,405 @@ private boolean REGEX_sempred(RuleContext _localctx, int predIndex) {
         return true;
     }
 
-    public static final String _serializedATN = "\3\u0430\ud6d1\u8206\uad2d\u4417\uaef1\u8d80\uaadd\2W\u027a\b\1\b\1\4"
-        + "\2\t\2\4\3\t\3\4\4\t\4\4\5\t\5\4\6\t\6\4\7\t\7\4\b\t\b\4\t\t\t\4\n\t\n"
-        + "\4\13\t\13\4\f\t\f\4\r\t\r\4\16\t\16\4\17\t\17\4\20\t\20\4\21\t\21\4\22"
-        + "\t\22\4\23\t\23\4\24\t\24\4\25\t\25\4\26\t\26\4\27\t\27\4\30\t\30\4\31"
-        + "\t\31\4\32\t\32\4\33\t\33\4\34\t\34\4\35\t\35\4\36\t\36\4\37\t\37\4 \t"
-        + " \4!\t!\4\"\t\"\4#\t#\4$\t$\4%\t%\4&\t&\4\'\t\'\4(\t(\4)\t)\4*\t*\4+\t"
-        + "+\4,\t,\4-\t-\4.\t.\4/\t/\4\60\t\60\4\61\t\61\4\62\t\62\4\63\t\63\4\64"
-        + "\t\64\4\65\t\65\4\66\t\66\4\67\t\67\48\t8\49\t9\4:\t:\4;\t;\4<\t<\4=\t"
-        + "=\4>\t>\4?\t?\4@\t@\4A\tA\4B\tB\4C\tC\4D\tD\4E\tE\4F\tF\4G\tG\4H\tH\4"
-        + "I\tI\4J\tJ\4K\tK\4L\tL\4M\tM\4N\tN\4O\tO\4P\tP\4Q\tQ\4R\tR\4S\tS\4T\t"
-        + "T\4U\tU\4V\tV\3\2\6\2\u00b0\n\2\r\2\16\2\u00b1\3\2\3\2\3\3\3\3\3\3\3\3"
-        + "\7\3\u00ba\n\3\f\3\16\3\u00bd\13\3\3\3\3\3\3\3\3\3\3\3\7\3\u00c4\n\3\f"
-        + "\3\16\3\u00c7\13\3\3\3\3\3\5\3\u00cb\n\3\3\3\3\3\3\4\3\4\3\5\3\5\3\6\3"
-        + "\6\3\7\3\7\3\b\3\b\3\t\3\t\3\n\3\n\3\n\3\n\3\13\3\13\3\13\3\13\3\13\3"
-        + "\f\3\f\3\r\3\r\3\16\3\16\3\16\3\17\3\17\3\17\3\20\3\20\3\20\3\20\3\20"
-        + "\3\21\3\21\3\21\3\21\3\21\3\21\3\22\3\22\3\22\3\23\3\23\3\23\3\23\3\24"
-        + "\3\24\3\24\3\24\3\24\3\24\3\24\3\24\3\24\3\25\3\25\3\25\3\25\3\25\3\25"
-        + "\3\26\3\26\3\26\3\26\3\26\3\26\3\26\3\27\3\27\3\27\3\27\3\30\3\30\3\30"
-        + "\3\30\3\31\3\31\3\31\3\31\3\31\3\31\3\32\3\32\3\32\3\32\3\32\3\32\3\33"
-        + "\3\33\3\33\3\33\3\33\3\34\3\34\3\34\3\34\3\34\3\34\3\34\3\34\3\34\3\34"
-        + "\3\34\3\35\3\35\3\36\3\36\3\37\3\37\3 \3 \3 \3!\3!\3\"\3\"\3#\3#\3$\3"
-        + "$\3$\3%\3%\3%\3&\3&\3&\3&\3\'\3\'\3(\3(\3(\3)\3)\3*\3*\3*\3+\3+\3+\3,"
-        + "\3,\3,\3,\3-\3-\3-\3.\3.\3.\3.\3/\3/\3\60\3\60\3\61\3\61\3\62\3\62\3\62"
-        + "\3\63\3\63\3\63\3\64\3\64\3\65\3\65\3\66\3\66\3\66\3\67\3\67\3\67\38\3"
-        + "8\38\39\39\39\3:\3:\3:\3:\3;\3;\3;\3<\3<\3<\3=\3=\3>\3>\3>\3?\3?\3?\3"
-        + "@\3@\3@\3A\3A\3A\3B\3B\3B\3C\3C\3C\3D\3D\3D\3E\3E\3E\3F\3F\3F\3F\3G\3"
-        + "G\3G\3G\3H\3H\3H\3H\3H\3I\3I\6I\u01ba\nI\rI\16I\u01bb\3I\5I\u01bf\nI\3"
-        + "J\3J\3J\6J\u01c4\nJ\rJ\16J\u01c5\3J\5J\u01c9\nJ\3K\3K\3K\7K\u01ce\nK\f"
-        + "K\16K\u01d1\13K\5K\u01d3\nK\3K\5K\u01d6\nK\3L\3L\3L\7L\u01db\nL\fL\16"
-        + "L\u01de\13L\5L\u01e0\nL\3L\3L\6L\u01e4\nL\rL\16L\u01e5\5L\u01e8\nL\3L"
-        + "\3L\5L\u01ec\nL\3L\6L\u01ef\nL\rL\16L\u01f0\5L\u01f3\nL\3L\5L\u01f6\n"
-        + "L\3M\3M\3M\3M\3M\3M\7M\u01fe\nM\fM\16M\u0201\13M\3M\3M\3M\3M\3M\3M\3M"
-        + "\7M\u020a\nM\fM\16M\u020d\13M\3M\5M\u0210\nM\3N\3N\3N\3N\6N\u0216\nN\r"
-        + "N\16N\u0217\3N\3N\7N\u021c\nN\fN\16N\u021f\13N\3N\3N\3O\3O\3O\3O\3O\3"
-        + "P\3P\3P\3P\3P\3P\3Q\3Q\3Q\3Q\3Q\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3"
-        + "R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3R\3"
-        + "R\3R\3R\5R\u0259\nR\3S\3S\3S\3S\3T\3T\7T\u0261\nT\fT\16T\u0264\13T\3U"
-        + "\3U\3U\7U\u0269\nU\fU\16U\u026c\13U\5U\u026e\nU\3U\3U\3V\3V\7V\u0274\n"
-        + "V\fV\16V\u0277\13V\3V\3V\7\u00bb\u00c5\u01ff\u020b\u0217\2W\4\3\6\4\b"
-        + "\5\n\6\f\7\16\b\20\t\22\n\24\13\26\f\30\r\32\16\34\17\36\20 \21\"\22$"
-        + "\23&\24(\25*\26,\27.\30\60\31\62\32\64\33\66\348\35:\36<\37> @!B\"D#F"
-        + "$H%J&L\'N(P)R*T+V,X-Z.\\/^\60`\61b\62d\63f\64h\65j\66l\67n8p9r:t;v<x="
-        + "z>|?~@\u0080A\u0082B\u0084C\u0086D\u0088E\u008aF\u008cG\u008eH\u0090I"
-        + "\u0092J\u0094K\u0096L\u0098M\u009aN\u009cO\u009eP\u00a0Q\u00a2R\u00a4"
-        + "S\u00a6T\u00a8U\u00aaV\u00acW\4\2\3\25\5\2\13\f\17\17\"\"\4\2\f\f\17\17"
-        + "\3\2\629\4\2NNnn\4\2ZZzz\5\2\62;CHch\3\2\63;\3\2\62;\b\2FFHHNNffhhnn\4"
-        + "\2GGgg\4\2--//\6\2FFHHffhh\4\2$$^^\4\2))^^\3\2\f\f\4\2\f\f\61\61\t\2W"
-        + "Weekknouuwwzz\5\2C\\aac|\6\2\62;C\\aac|\u02a0\2\4\3\2\2\2\2\6\3\2\2\2"
-        + "\2\b\3\2\2\2\2\n\3\2\2\2\2\f\3\2\2\2\2\16\3\2\2\2\2\20\3\2\2\2\2\22\3"
-        + "\2\2\2\2\24\3\2\2\2\2\26\3\2\2\2\2\30\3\2\2\2\2\32\3\2\2\2\2\34\3\2\2"
-        + "\2\2\36\3\2\2\2\2 \3\2\2\2\2\"\3\2\2\2\2$\3\2\2\2\2&\3\2\2\2\2(\3\2\2"
-        + "\2\2*\3\2\2\2\2,\3\2\2\2\2.\3\2\2\2\2\60\3\2\2\2\2\62\3\2\2\2\2\64\3\2"
-        + "\2\2\2\66\3\2\2\2\28\3\2\2\2\2:\3\2\2\2\2<\3\2\2\2\2>\3\2\2\2\2@\3\2\2"
-        + "\2\2B\3\2\2\2\2D\3\2\2\2\2F\3\2\2\2\2H\3\2\2\2\2J\3\2\2\2\2L\3\2\2\2\2"
-        + "N\3\2\2\2\2P\3\2\2\2\2R\3\2\2\2\2T\3\2\2\2\2V\3\2\2\2\2X\3\2\2\2\2Z\3"
-        + "\2\2\2\2\\\3\2\2\2\2^\3\2\2\2\2`\3\2\2\2\2b\3\2\2\2\2d\3\2\2\2\2f\3\2"
-        + "\2\2\2h\3\2\2\2\2j\3\2\2\2\2l\3\2\2\2\2n\3\2\2\2\2p\3\2\2\2\2r\3\2\2\2"
-        + "\2t\3\2\2\2\2v\3\2\2\2\2x\3\2\2\2\2z\3\2\2\2\2|\3\2\2\2\2~\3\2\2\2\2\u0080"
-        + "\3\2\2\2\2\u0082\3\2\2\2\2\u0084\3\2\2\2\2\u0086\3\2\2\2\2\u0088\3\2\2"
-        + "\2\2\u008a\3\2\2\2\2\u008c\3\2\2\2\2\u008e\3\2\2\2\2\u0090\3\2\2\2\2\u0092"
-        + "\3\2\2\2\2\u0094\3\2\2\2\2\u0096\3\2\2\2\2\u0098\3\2\2\2\2\u009a\3\2\2"
-        + "\2\2\u009c\3\2\2\2\2\u009e\3\2\2\2\2\u00a0\3\2\2\2\2\u00a2\3\2\2\2\2\u00a4"
-        + "\3\2\2\2\2\u00a6\3\2\2\2\2\u00a8\3\2\2\2\3\u00aa\3\2\2\2\3\u00ac\3\2\2"
-        + "\2\4\u00af\3\2\2\2\6\u00ca\3\2\2\2\b\u00ce\3\2\2\2\n\u00d0\3\2\2\2\f\u00d2"
-        + "\3\2\2\2\16\u00d4\3\2\2\2\20\u00d6\3\2\2\2\22\u00d8\3\2\2\2\24\u00da\3"
-        + "\2\2\2\26\u00de\3\2\2\2\30\u00e3\3\2\2\2\32\u00e5\3\2\2\2\34\u00e7\3\2"
-        + "\2\2\36\u00ea\3\2\2\2 \u00ed\3\2\2\2\"\u00f2\3\2\2\2$\u00f8\3\2\2\2&\u00fb"
-        + "\3\2\2\2(\u00ff\3\2\2\2*\u0108\3\2\2\2,\u010e\3\2\2\2.\u0115\3\2\2\2\60"
-        + "\u0119\3\2\2\2\62\u011d\3\2\2\2\64\u0123\3\2\2\2\66\u0129\3\2\2\28\u012e"
-        + "\3\2\2\2:\u0139\3\2\2\2<\u013b\3\2\2\2>\u013d\3\2\2\2@\u013f\3\2\2\2B"
-        + "\u0142\3\2\2\2D\u0144\3\2\2\2F\u0146\3\2\2\2H\u0148\3\2\2\2J\u014b\3\2"
-        + "\2\2L\u014e\3\2\2\2N\u0152\3\2\2\2P\u0154\3\2\2\2R\u0157\3\2\2\2T\u0159"
-        + "\3\2\2\2V\u015c\3\2\2\2X\u015f\3\2\2\2Z\u0163\3\2\2\2\\\u0166\3\2\2\2"
-        + "^\u016a\3\2\2\2`\u016c\3\2\2\2b\u016e\3\2\2\2d\u0170\3\2\2\2f\u0173\3"
-        + "\2\2\2h\u0176\3\2\2\2j\u0178\3\2\2\2l\u017a\3\2\2\2n\u017d\3\2\2\2p\u0180"
-        + "\3\2\2\2r\u0183\3\2\2\2t\u0186\3\2\2\2v\u018a\3\2\2\2x\u018d\3\2\2\2z"
-        + "\u0190\3\2\2\2|\u0192\3\2\2\2~\u0195\3\2\2\2\u0080\u0198\3\2\2\2\u0082"
-        + "\u019b\3\2\2\2\u0084\u019e\3\2\2\2\u0086\u01a1\3\2\2\2\u0088\u01a4\3\2"
-        + "\2\2\u008a\u01a7\3\2\2\2\u008c\u01aa\3\2\2\2\u008e\u01ae\3\2\2\2\u0090"
-        + "\u01b2\3\2\2\2\u0092\u01b7\3\2\2\2\u0094\u01c0\3\2\2\2\u0096\u01d2\3\2"
-        + "\2\2\u0098\u01df\3\2\2\2\u009a\u020f\3\2\2\2\u009c\u0211\3\2\2\2\u009e"
-        + "\u0222\3\2\2\2\u00a0\u0227\3\2\2\2\u00a2\u022d\3\2\2\2\u00a4\u0258\3\2"
-        + "\2\2\u00a6\u025a\3\2\2\2\u00a8\u025e\3\2\2\2\u00aa\u026d\3\2\2\2\u00ac"
-        + "\u0271\3\2\2\2\u00ae\u00b0\t\2\2\2\u00af\u00ae\3\2\2\2\u00b0\u00b1\3\2"
-        + "\2\2\u00b1\u00af\3\2\2\2\u00b1\u00b2\3\2\2\2\u00b2\u00b3\3\2\2\2\u00b3"
-        + "\u00b4\b\2\2\2\u00b4\5\3\2\2\2\u00b5\u00b6\7\61\2\2\u00b6\u00b7\7\61\2"
-        + "\2\u00b7\u00bb\3\2\2\2\u00b8\u00ba\13\2\2\2\u00b9\u00b8\3\2\2\2\u00ba"
-        + "\u00bd\3\2\2\2\u00bb\u00bc\3\2\2\2\u00bb\u00b9\3\2\2\2\u00bc\u00be\3\2"
-        + "\2\2\u00bd\u00bb\3\2\2\2\u00be\u00cb\t\3\2\2\u00bf\u00c0\7\61\2\2\u00c0"
-        + "\u00c1\7,\2\2\u00c1\u00c5\3\2\2\2\u00c2\u00c4\13\2\2\2\u00c3\u00c2\3\2"
-        + "\2\2\u00c4\u00c7\3\2\2\2\u00c5\u00c6\3\2\2\2\u00c5\u00c3\3\2\2\2\u00c6"
-        + "\u00c8\3\2\2\2\u00c7\u00c5\3\2\2\2\u00c8\u00c9\7,\2\2\u00c9\u00cb\7\61"
-        + "\2\2\u00ca\u00b5\3\2\2\2\u00ca\u00bf\3\2\2\2\u00cb\u00cc\3\2\2\2\u00cc"
-        + "\u00cd\b\3\2\2\u00cd\7\3\2\2\2\u00ce\u00cf\7}\2\2\u00cf\t\3\2\2\2\u00d0"
-        + "\u00d1\7\177\2\2\u00d1\13\3\2\2\2\u00d2\u00d3\7]\2\2\u00d3\r\3\2\2\2\u00d4"
-        + "\u00d5\7_\2\2\u00d5\17\3\2\2\2\u00d6\u00d7\7*\2\2\u00d7\21\3\2\2\2\u00d8"
-        + "\u00d9\7+\2\2\u00d9\23\3\2\2\2\u00da\u00db\7\60\2\2\u00db\u00dc\3\2\2"
-        + "\2\u00dc\u00dd\b\n\3\2\u00dd\25\3\2\2\2\u00de\u00df\7A\2\2\u00df\u00e0"
-        + "\7\60\2\2\u00e0\u00e1\3\2\2\2\u00e1\u00e2\b\13\3\2\u00e2\27\3\2\2\2\u00e3"
-        + "\u00e4\7.\2\2\u00e4\31\3\2\2\2\u00e5\u00e6\7=\2\2\u00e6\33\3\2\2\2\u00e7"
-        + "\u00e8\7k\2\2\u00e8\u00e9\7h\2\2\u00e9\35\3\2\2\2\u00ea\u00eb\7k\2\2\u00eb"
-        + "\u00ec\7p\2\2\u00ec\37\3\2\2\2\u00ed\u00ee\7g\2\2\u00ee\u00ef\7n\2\2\u00ef"
-        + "\u00f0\7u\2\2\u00f0\u00f1\7g\2\2\u00f1!\3\2\2\2\u00f2\u00f3\7y\2\2\u00f3"
-        + "\u00f4\7j\2\2\u00f4\u00f5\7k\2\2\u00f5\u00f6\7n\2\2\u00f6\u00f7\7g\2\2"
-        + "\u00f7#\3\2\2\2\u00f8\u00f9\7f\2\2\u00f9\u00fa\7q\2\2\u00fa%\3\2\2\2\u00fb"
-        + "\u00fc\7h\2\2\u00fc\u00fd\7q\2\2\u00fd\u00fe\7t\2\2\u00fe\'\3\2\2\2\u00ff"
-        + "\u0100\7e\2\2\u0100\u0101\7q\2\2\u0101\u0102\7p\2\2\u0102\u0103\7v\2\2"
-        + "\u0103\u0104\7k\2\2\u0104\u0105\7p\2\2\u0105\u0106\7w\2\2\u0106\u0107"
-        + "\7g\2\2\u0107)\3\2\2\2\u0108\u0109\7d\2\2\u0109\u010a\7t\2\2\u010a\u010b"
-        + "\7g\2\2\u010b\u010c\7c\2\2\u010c\u010d\7m\2\2\u010d+\3\2\2\2\u010e\u010f"
-        + "\7t\2\2\u010f\u0110\7g\2\2\u0110\u0111\7v\2\2\u0111\u0112\7w\2\2\u0112"
-        + "\u0113\7t\2\2\u0113\u0114\7p\2\2\u0114-\3\2\2\2\u0115\u0116\7p\2\2\u0116"
-        + "\u0117\7g\2\2\u0117\u0118\7y\2\2\u0118/\3\2\2\2\u0119\u011a\7v\2\2\u011a"
-        + "\u011b\7t\2\2\u011b\u011c\7{\2\2\u011c\61\3\2\2\2\u011d\u011e\7e\2\2\u011e"
-        + "\u011f\7c\2\2\u011f\u0120\7v\2\2\u0120\u0121\7e\2\2\u0121\u0122\7j\2\2"
-        + "\u0122\63\3\2\2\2\u0123\u0124\7v\2\2\u0124\u0125\7j\2\2\u0125\u0126\7"
-        + "t\2\2\u0126\u0127\7q\2\2\u0127\u0128\7y\2\2\u0128\65\3\2\2\2\u0129\u012a"
-        + "\7v\2\2\u012a\u012b\7j\2\2\u012b\u012c\7k\2\2\u012c\u012d\7u\2\2\u012d"
-        + "\67\3\2\2\2\u012e\u012f\7k\2\2\u012f\u0130\7p\2\2\u0130\u0131\7u\2\2\u0131"
-        + "\u0132\7v\2\2\u0132\u0133\7c\2\2\u0133\u0134\7p\2\2\u0134\u0135\7e\2\2"
-        + "\u0135\u0136\7g\2\2\u0136\u0137\7q\2\2\u0137\u0138\7h\2\2\u01389\3\2\2"
-        + "\2\u0139\u013a\7#\2\2\u013a;\3\2\2\2\u013b\u013c\7\u0080\2\2\u013c=\3"
-        + "\2\2\2\u013d\u013e\7,\2\2\u013e?\3\2\2\2\u013f\u0140\7\61\2\2\u0140\u0141"
-        + "\6 \2\2\u0141A\3\2\2\2\u0142\u0143\7\'\2\2\u0143C\3\2\2\2\u0144\u0145"
-        + "\7-\2\2\u0145E\3\2\2\2\u0146\u0147\7/\2\2\u0147G\3\2\2\2\u0148\u0149\7"
-        + ">\2\2\u0149\u014a\7>\2\2\u014aI\3\2\2\2\u014b\u014c\7@\2\2\u014c\u014d"
-        + "\7@\2\2\u014dK\3\2\2\2\u014e\u014f\7@\2\2\u014f\u0150\7@\2\2\u0150\u0151"
-        + "\7@\2\2\u0151M\3\2\2\2\u0152\u0153\7>\2\2\u0153O\3\2\2\2\u0154\u0155\7"
-        + ">\2\2\u0155\u0156\7?\2\2\u0156Q\3\2\2\2\u0157\u0158\7@\2\2\u0158S\3\2"
-        + "\2\2\u0159\u015a\7@\2\2\u015a\u015b\7?\2\2\u015bU\3\2\2\2\u015c\u015d"
-        + "\7?\2\2\u015d\u015e\7?\2\2\u015eW\3\2\2\2\u015f\u0160\7?\2\2\u0160\u0161"
-        + "\7?\2\2\u0161\u0162\7?\2\2\u0162Y\3\2\2\2\u0163\u0164\7#\2\2\u0164\u0165"
-        + "\7?\2\2\u0165[\3\2\2\2\u0166\u0167\7#\2\2\u0167\u0168\7?\2\2\u0168\u0169"
-        + "\7?\2\2\u0169]\3\2\2\2\u016a\u016b\7(\2\2\u016b_\3\2\2\2\u016c\u016d\7"
-        + "`\2\2\u016da\3\2\2\2\u016e\u016f\7~\2\2\u016fc\3\2\2\2\u0170\u0171\7("
-        + "\2\2\u0171\u0172\7(\2\2\u0172e\3\2\2\2\u0173\u0174\7~\2\2\u0174\u0175"
-        + "\7~\2\2\u0175g\3\2\2\2\u0176\u0177\7A\2\2\u0177i\3\2\2\2\u0178\u0179\7"
-        + "<\2\2\u0179k\3\2\2\2\u017a\u017b\7A\2\2\u017b\u017c\7<\2\2\u017cm\3\2"
-        + "\2\2\u017d\u017e\7<\2\2\u017e\u017f\7<\2\2\u017fo\3\2\2\2\u0180\u0181"
-        + "\7/\2\2\u0181\u0182\7@\2\2\u0182q\3\2\2\2\u0183\u0184\7?\2\2\u0184\u0185"
-        + "\7\u0080\2\2\u0185s\3\2\2\2\u0186\u0187\7?\2\2\u0187\u0188\7?\2\2\u0188"
-        + "\u0189\7\u0080\2\2\u0189u\3\2\2\2\u018a\u018b\7-\2\2\u018b\u018c\7-\2"
-        + "\2\u018cw\3\2\2\2\u018d\u018e\7/\2\2\u018e\u018f\7/\2\2\u018fy\3\2\2\2"
-        + "\u0190\u0191\7?\2\2\u0191{\3\2\2\2\u0192\u0193\7-\2\2\u0193\u0194\7?\2"
-        + "\2\u0194}\3\2\2\2\u0195\u0196\7/\2\2\u0196\u0197\7?\2\2\u0197\177\3\2"
-        + "\2\2\u0198\u0199\7,\2\2\u0199\u019a\7?\2\2\u019a\u0081\3\2\2\2\u019b\u019c"
-        + "\7\61\2\2\u019c\u019d\7?\2\2\u019d\u0083\3\2\2\2\u019e\u019f\7\'\2\2\u019f"
-        + "\u01a0\7?\2\2\u01a0\u0085\3\2\2\2\u01a1\u01a2\7(\2\2\u01a2\u01a3\7?\2"
-        + "\2\u01a3\u0087\3\2\2\2\u01a4\u01a5\7`\2\2\u01a5\u01a6\7?\2\2\u01a6\u0089"
-        + "\3\2\2\2\u01a7\u01a8\7~\2\2\u01a8\u01a9\7?\2\2\u01a9\u008b\3\2\2\2\u01aa"
-        + "\u01ab\7>\2\2\u01ab\u01ac\7>\2\2\u01ac\u01ad\7?\2\2\u01ad\u008d\3\2\2"
-        + "\2\u01ae\u01af\7@\2\2\u01af\u01b0\7@\2\2\u01b0\u01b1\7?\2\2\u01b1\u008f"
-        + "\3\2\2\2\u01b2\u01b3\7@\2\2\u01b3\u01b4\7@\2\2\u01b4\u01b5\7@\2\2\u01b5"
-        + "\u01b6\7?\2\2\u01b6\u0091\3\2\2\2\u01b7\u01b9\7\62\2\2\u01b8\u01ba\t\4"
-        + "\2\2\u01b9\u01b8\3\2\2\2\u01ba\u01bb\3\2\2\2\u01bb\u01b9\3\2\2\2\u01bb"
-        + "\u01bc\3\2\2\2\u01bc\u01be\3\2\2\2\u01bd\u01bf\t\5\2\2\u01be\u01bd\3\2"
-        + "\2\2\u01be\u01bf\3\2\2\2\u01bf\u0093\3\2\2\2\u01c0\u01c1\7\62\2\2\u01c1"
-        + "\u01c3\t\6\2\2\u01c2\u01c4\t\7\2\2\u01c3\u01c2\3\2\2\2\u01c4\u01c5\3\2"
-        + "\2\2\u01c5\u01c3\3\2\2\2\u01c5\u01c6\3\2\2\2\u01c6\u01c8\3\2\2\2\u01c7"
-        + "\u01c9\t\5\2\2\u01c8\u01c7\3\2\2\2\u01c8\u01c9\3\2\2\2\u01c9\u0095\3\2"
-        + "\2\2\u01ca\u01d3\7\62\2\2\u01cb\u01cf\t\b\2\2\u01cc\u01ce\t\t\2\2\u01cd"
-        + "\u01cc\3\2\2\2\u01ce\u01d1\3\2\2\2\u01cf\u01cd\3\2\2\2\u01cf\u01d0\3\2"
-        + "\2\2\u01d0\u01d3\3\2\2\2\u01d1\u01cf\3\2\2\2\u01d2\u01ca\3\2\2\2\u01d2"
-        + "\u01cb\3\2\2\2\u01d3\u01d5\3\2\2\2\u01d4\u01d6\t\n\2\2\u01d5\u01d4\3\2"
-        + "\2\2\u01d5\u01d6\3\2\2\2\u01d6\u0097\3\2\2\2\u01d7\u01e0\7\62\2\2\u01d8"
-        + "\u01dc\t\b\2\2\u01d9\u01db\t\t\2\2\u01da\u01d9\3\2\2\2\u01db\u01de\3\2"
-        + "\2\2\u01dc\u01da\3\2\2\2\u01dc\u01dd\3\2\2\2\u01dd\u01e0\3\2\2\2\u01de"
-        + "\u01dc\3\2\2\2\u01df\u01d7\3\2\2\2\u01df\u01d8\3\2\2\2\u01e0\u01e7\3\2"
-        + "\2\2\u01e1\u01e3\5\24\n\2\u01e2\u01e4\t\t\2\2\u01e3\u01e2\3\2\2\2\u01e4"
-        + "\u01e5\3\2\2\2\u01e5\u01e3\3\2\2\2\u01e5\u01e6\3\2\2\2\u01e6\u01e8\3\2"
-        + "\2\2\u01e7\u01e1\3\2\2\2\u01e7\u01e8\3\2\2\2\u01e8\u01f2\3\2\2\2\u01e9"
-        + "\u01eb\t\13\2\2\u01ea\u01ec\t\f\2\2\u01eb\u01ea\3\2\2\2\u01eb\u01ec\3"
-        + "\2\2\2\u01ec\u01ee\3\2\2\2\u01ed\u01ef\t\t\2\2\u01ee\u01ed\3\2\2\2\u01ef"
-        + "\u01f0\3\2\2\2\u01f0\u01ee\3\2\2\2\u01f0\u01f1\3\2\2\2\u01f1\u01f3\3\2"
-        + "\2\2\u01f2\u01e9\3\2\2\2\u01f2\u01f3\3\2\2\2\u01f3\u01f5\3\2\2\2\u01f4"
-        + "\u01f6\t\r\2\2\u01f5\u01f4\3\2\2\2\u01f5\u01f6\3\2\2\2\u01f6\u0099\3\2"
-        + "\2\2\u01f7\u01ff\7$\2\2\u01f8\u01f9\7^\2\2\u01f9\u01fe\7$\2\2\u01fa\u01fb"
-        + "\7^\2\2\u01fb\u01fe\7^\2\2\u01fc\u01fe\n\16\2\2\u01fd\u01f8\3\2\2\2\u01fd"
-        + "\u01fa\3\2\2\2\u01fd\u01fc\3\2\2\2\u01fe\u0201\3\2\2\2\u01ff\u0200\3\2"
-        + "\2\2\u01ff\u01fd\3\2\2\2\u0200\u0202\3\2\2\2\u0201\u01ff\3\2\2\2\u0202"
-        + "\u0210\7$\2\2\u0203\u020b\7)\2\2\u0204\u0205\7^\2\2\u0205\u020a\7)\2\2"
-        + "\u0206\u0207\7^\2\2\u0207\u020a\7^\2\2\u0208\u020a\n\17\2\2\u0209\u0204"
-        + "\3\2\2\2\u0209\u0206\3\2\2\2\u0209\u0208\3\2\2\2\u020a\u020d\3\2\2\2\u020b"
-        + "\u020c\3\2\2\2\u020b\u0209\3\2\2\2\u020c\u020e\3\2\2\2\u020d\u020b\3\2"
-        + "\2\2\u020e\u0210\7)\2\2\u020f\u01f7\3\2\2\2\u020f\u0203\3\2\2\2\u0210"
-        + "\u009b\3\2\2\2\u0211\u0215\7\61\2\2\u0212\u0213\7^\2\2\u0213\u0216\n\20"
-        + "\2\2\u0214\u0216\n\21\2\2\u0215\u0212\3\2\2\2\u0215\u0214\3\2\2\2\u0216"
-        + "\u0217\3\2\2\2\u0217\u0218\3\2\2\2\u0217\u0215\3\2\2\2\u0218\u0219\3\2"
-        + "\2\2\u0219\u021d\7\61\2\2\u021a\u021c\t\22\2\2\u021b\u021a\3\2\2\2\u021c"
-        + "\u021f\3\2\2\2\u021d\u021b\3\2\2\2\u021d\u021e\3\2\2\2\u021e\u0220\3\2"
-        + "\2\2\u021f\u021d\3\2\2\2\u0220\u0221\6N\3\2\u0221\u009d\3\2\2\2\u0222"
-        + "\u0223\7v\2\2\u0223\u0224\7t\2\2\u0224\u0225\7w\2\2\u0225\u0226\7g\2\2"
-        + "\u0226\u009f\3\2\2\2\u0227\u0228\7h\2\2\u0228\u0229\7c\2\2\u0229\u022a"
-        + "\7n\2\2\u022a\u022b\7u\2\2\u022b\u022c\7g\2\2\u022c\u00a1\3\2\2\2\u022d"
-        + "\u022e\7p\2\2\u022e\u022f\7w\2\2\u022f\u0230\7n\2\2\u0230\u0231\7n\2\2"
-        + "\u0231\u00a3\3\2\2\2\u0232\u0233\7d\2\2\u0233\u0234\7q\2\2\u0234\u0235"
-        + "\7q\2\2\u0235\u0236\7n\2\2\u0236\u0237\7g\2\2\u0237\u0238\7c\2\2\u0238"
-        + "\u0259\7p\2\2\u0239\u023a\7d\2\2\u023a\u023b\7{\2\2\u023b\u023c\7v\2\2"
-        + "\u023c\u0259\7g\2\2\u023d\u023e\7u\2\2\u023e\u023f\7j\2\2\u023f\u0240"
-        + "\7q\2\2\u0240\u0241\7t\2\2\u0241\u0259\7v\2\2\u0242\u0243\7e\2\2\u0243"
-        + "\u0244\7j\2\2\u0244\u0245\7c\2\2\u0245\u0259\7t\2\2\u0246\u0247\7k\2\2"
-        + "\u0247\u0248\7p\2\2\u0248\u0259\7v\2\2\u0249\u024a\7n\2\2\u024a\u024b"
-        + "\7q\2\2\u024b\u024c\7p\2\2\u024c\u0259\7i\2\2\u024d\u024e\7h\2\2\u024e"
-        + "\u024f\7n\2\2\u024f\u0250\7q\2\2\u0250\u0251\7c\2\2\u0251\u0259\7v\2\2"
-        + "\u0252\u0253\7f\2\2\u0253\u0254\7q\2\2\u0254\u0255\7w\2\2\u0255\u0256"
-        + "\7d\2\2\u0256\u0257\7n\2\2\u0257\u0259\7g\2\2\u0258\u0232\3\2\2\2\u0258"
-        + "\u0239\3\2\2\2\u0258\u023d\3\2\2\2\u0258\u0242\3\2\2\2\u0258\u0246\3\2"
-        + "\2\2\u0258\u0249\3\2\2\2\u0258\u024d\3\2\2\2\u0258\u0252\3\2\2\2\u0259"
-        + "\u00a5\3\2\2\2\u025a\u025b\7f\2\2\u025b\u025c\7g\2\2\u025c\u025d\7h\2"
-        + "\2\u025d\u00a7\3\2\2\2\u025e\u0262\t\23\2\2\u025f\u0261\t\24\2\2\u0260"
-        + "\u025f\3\2\2\2\u0261\u0264\3\2\2\2\u0262\u0260\3\2\2\2\u0262\u0263\3\2"
-        + "\2\2\u0263\u00a9\3\2\2\2\u0264\u0262\3\2\2\2\u0265\u026e\7\62\2\2\u0266"
-        + "\u026a\t\b\2\2\u0267\u0269\t\t\2\2\u0268\u0267\3\2\2\2\u0269\u026c\3\2"
-        + "\2\2\u026a\u0268\3\2\2\2\u026a\u026b\3\2\2\2\u026b\u026e\3\2\2\2\u026c"
-        + "\u026a\3\2\2\2\u026d\u0265\3\2\2\2\u026d\u0266\3\2\2\2\u026e\u026f\3\2"
-        + "\2\2\u026f\u0270\bU\4\2\u0270\u00ab\3\2\2\2\u0271\u0275\t\23\2\2\u0272"
-        + "\u0274\t\24\2\2\u0273\u0272\3\2\2\2\u0274\u0277\3\2\2\2\u0275\u0273\3"
-        + "\2\2\2\u0275\u0276\3\2\2\2\u0276\u0278\3\2\2\2\u0277\u0275\3\2\2\2\u0278"
-        + "\u0279\bV\4\2\u0279\u00ad\3\2\2\2$\2\3\u00b1\u00bb\u00c5\u00ca\u01bb\u01be"
-        + "\u01c5\u01c8\u01cf\u01d2\u01d5\u01dc\u01df\u01e5\u01e7\u01eb\u01f0\u01f2"
-        + "\u01f5\u01fd\u01ff\u0209\u020b\u020f\u0215\u0217\u021d\u0258\u0262\u026a"
-        + "\u026d\u0275\5\b\2\2\4\3\2\4\2\2";
+    public static final String _serializedATN = "\u0004\u0000U\u0278\u0006\uffff\uffff\u0006\uffff\uffff\u0002\u0000\u0007"
+        + "\u0000\u0002\u0001\u0007\u0001\u0002\u0002\u0007\u0002\u0002\u0003\u0007"
+        + "\u0003\u0002\u0004\u0007\u0004\u0002\u0005\u0007\u0005\u0002\u0006\u0007"
+        + "\u0006\u0002\u0007\u0007\u0007\u0002\b\u0007\b\u0002\t\u0007\t\u0002\n"
+        + "\u0007\n\u0002\u000b\u0007\u000b\u0002\f\u0007\f\u0002\r\u0007\r\u0002"
+        + "\u000e\u0007\u000e\u0002\u000f\u0007\u000f\u0002\u0010\u0007\u0010\u0002"
+        + "\u0011\u0007\u0011\u0002\u0012\u0007\u0012\u0002\u0013\u0007\u0013\u0002"
+        + "\u0014\u0007\u0014\u0002\u0015\u0007\u0015\u0002\u0016\u0007\u0016\u0002"
+        + "\u0017\u0007\u0017\u0002\u0018\u0007\u0018\u0002\u0019\u0007\u0019\u0002"
+        + "\u001a\u0007\u001a\u0002\u001b\u0007\u001b\u0002\u001c\u0007\u001c\u0002"
+        + "\u001d\u0007\u001d\u0002\u001e\u0007\u001e\u0002\u001f\u0007\u001f\u0002"
+        + " \u0007 \u0002!\u0007!\u0002\"\u0007\"\u0002#\u0007#\u0002$\u0007$\u0002"
+        + "%\u0007%\u0002&\u0007&\u0002\'\u0007\'\u0002(\u0007(\u0002)\u0007)\u0002"
+        + "*\u0007*\u0002+\u0007+\u0002,\u0007,\u0002-\u0007-\u0002.\u0007.\u0002"
+        + "/\u0007/\u00020\u00070\u00021\u00071\u00022\u00072\u00023\u00073\u0002"
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+        + "\u0005b\u0000\u0000\u0231\u0232\u0005o\u0000\u0000\u0232\u0233\u0005o"
+        + "\u0000\u0000\u0233\u0234\u0005l\u0000\u0000\u0234\u0235\u0005e\u0000\u0000"
+        + "\u0235\u0236\u0005a\u0000\u0000\u0236\u0257\u0005n\u0000\u0000\u0237\u0238"
+        + "\u0005b\u0000\u0000\u0238\u0239\u0005y\u0000\u0000\u0239\u023a\u0005t"
+        + "\u0000\u0000\u023a\u0257\u0005e\u0000\u0000\u023b\u023c\u0005s\u0000\u0000"
+        + "\u023c\u023d\u0005h\u0000\u0000\u023d\u023e\u0005o\u0000\u0000\u023e\u023f"
+        + "\u0005r\u0000\u0000\u023f\u0257\u0005t\u0000\u0000\u0240\u0241\u0005c"
+        + "\u0000\u0000\u0241\u0242\u0005h\u0000\u0000\u0242\u0243\u0005a\u0000\u0000"
+        + "\u0243\u0257\u0005r\u0000\u0000\u0244\u0245\u0005i\u0000\u0000\u0245\u0246"
+        + "\u0005n\u0000\u0000\u0246\u0257\u0005t\u0000\u0000\u0247\u0248\u0005l"
+        + "\u0000\u0000\u0248\u0249\u0005o\u0000\u0000\u0249\u024a\u0005n\u0000\u0000"
+        + "\u024a\u0257\u0005g\u0000\u0000\u024b\u024c\u0005f\u0000\u0000\u024c\u024d"
+        + "\u0005l\u0000\u0000\u024d\u024e\u0005o\u0000\u0000\u024e\u024f\u0005a"
+        + "\u0000\u0000\u024f\u0257\u0005t\u0000\u0000\u0250\u0251\u0005d\u0000\u0000"
+        + "\u0251\u0252\u0005o\u0000\u0000\u0252\u0253\u0005u\u0000\u0000\u0253\u0254"
+        + "\u0005b\u0000\u0000\u0254\u0255\u0005l\u0000\u0000\u0255\u0257\u0005e"
+        + "\u0000\u0000\u0256\u0230\u0001\u0000\u0000\u0000\u0256\u0237\u0001\u0000"
+        + "\u0000\u0000\u0256\u023b\u0001\u0000\u0000\u0000\u0256\u0240\u0001\u0000"
+        + "\u0000\u0000\u0256\u0244\u0001\u0000\u0000\u0000\u0256\u0247\u0001\u0000"
+        + "\u0000\u0000\u0256\u024b\u0001\u0000\u0000\u0000\u0256\u0250\u0001\u0000"
+        + "\u0000\u0000\u0257\u00a3\u0001\u0000\u0000\u0000\u0258\u0259\u0005d\u0000"
+        + "\u0000\u0259\u025a\u0005e\u0000\u0000\u025a\u025b\u0005f\u0000\u0000\u025b"
+        + "\u00a5\u0001\u0000\u0000\u0000\u025c\u0260\u0007\u0011\u0000\u0000\u025d"
+        + "\u025f\u0007\u0012\u0000\u0000\u025e\u025d\u0001\u0000\u0000\u0000\u025f"
+        + "\u0262\u0001\u0000\u0000\u0000\u0260\u025e\u0001\u0000\u0000\u0000\u0260"
+        + "\u0261\u0001\u0000\u0000\u0000\u0261\u00a7\u0001\u0000\u0000\u0000\u0262"
+        + "\u0260\u0001\u0000\u0000\u0000\u0263\u026c\u00050\u0000\u0000\u0264\u0268"
+        + "\u0007\u0006\u0000\u0000\u0265\u0267\u0007\u0007\u0000\u0000\u0266\u0265"
+        + "\u0001\u0000\u0000\u0000\u0267\u026a\u0001\u0000\u0000\u0000\u0268\u0266"
+        + "\u0001\u0000\u0000\u0000\u0268\u0269\u0001\u0000\u0000\u0000\u0269\u026c"
+        + "\u0001\u0000\u0000\u0000\u026a\u0268\u0001\u0000\u0000\u0000\u026b\u0263"
+        + "\u0001\u0000\u0000\u0000\u026b\u0264\u0001\u0000\u0000\u0000\u026c\u026d"
+        + "\u0001\u0000\u0000\u0000\u026d\u026e\u0006S\u0002\u0000\u026e\u00a9\u0001"
+        + "\u0000\u0000\u0000\u026f\u0273\u0007\u0011\u0000\u0000\u0270\u0272\u0007"
+        + "\u0012\u0000\u0000\u0271\u0270\u0001\u0000\u0000\u0000\u0272\u0275\u0001"
+        + "\u0000\u0000\u0000\u0273\u0271\u0001\u0000\u0000\u0000\u0273\u0274\u0001"
+        + "\u0000\u0000\u0000\u0274\u0276\u0001\u0000\u0000\u0000\u0275\u0273\u0001"
+        + "\u0000\u0000\u0000\u0276\u0277\u0006T\u0002\u0000\u0277\u00ab\u0001\u0000"
+        + "\u0000\u0000\"\u0000\u0001\u00af\u00b9\u00c3\u00c8\u01b9\u01bc\u01c3\u01c6"
+        + "\u01cd\u01d0\u01d3\u01da\u01dd\u01e3\u01e5\u01e9\u01ee\u01f0\u01f3\u01fb"
+        + "\u01fd\u0207\u0209\u020d\u0213\u0215\u021b\u0256\u0260\u0268\u026b\u0273"
+        + "\u0003\u0006\u0000\u0000\u0002\u0001\u0000\u0002\u0000\u0000";
     public static final ATN _ATN = new ATNDeserializer().deserialize(_serializedATN.toCharArray());
     static {
         _decisionToDFA = new DFA[_ATN.getNumberOfDecisions()];
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParser.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParser.java
index 1e064724c2451..40e76194f50b2 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParser.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParser.java
@@ -30,20 +30,33 @@
  * Modifications Copyright OpenSearch Contributors. See
  * GitHub history for details.
  */
-
 package org.opensearch.painless.antlr;
 
-import org.antlr.v4.runtime.atn.*;
+import org.antlr.v4.runtime.FailedPredicateException;
+import org.antlr.v4.runtime.NoViableAltException;
+import org.antlr.v4.runtime.Parser;
+import org.antlr.v4.runtime.ParserRuleContext;
+import org.antlr.v4.runtime.RecognitionException;
+import org.antlr.v4.runtime.RuleContext;
+import org.antlr.v4.runtime.RuntimeMetaData;
+import org.antlr.v4.runtime.Token;
+import org.antlr.v4.runtime.TokenStream;
+import org.antlr.v4.runtime.Vocabulary;
+import org.antlr.v4.runtime.VocabularyImpl;
+import org.antlr.v4.runtime.atn.ATN;
+import org.antlr.v4.runtime.atn.ATNDeserializer;
+import org.antlr.v4.runtime.atn.ParserATNSimulator;
+import org.antlr.v4.runtime.atn.PredictionContextCache;
 import org.antlr.v4.runtime.dfa.DFA;
-import org.antlr.v4.runtime.*;
-import org.antlr.v4.runtime.misc.*;
-import org.antlr.v4.runtime.tree.*;
+import org.antlr.v4.runtime.tree.ParseTreeVisitor;
+import org.antlr.v4.runtime.tree.TerminalNode;
+
 import java.util.List;
 
-@SuppressWarnings({ "all", "warnings", "unchecked", "unused", "cast" })
+@SuppressWarnings({ "all", "warnings", "unchecked", "unused", "cast", "CheckReturnValue" })
 class PainlessParser extends Parser {
     static {
-        RuntimeMetaData.checkVersion("4.5.3", RuntimeMetaData.VERSION);
+        RuntimeMetaData.checkVersion("4.11.1", RuntimeMetaData.VERSION);
     }
 
     protected static final DFA[] _decisionToDFA;
@@ -63,218 +76,232 @@ class PainlessParser extends Parser {
         RULE_refcasttype = 22, RULE_chain = 23, RULE_primary = 24, RULE_postfix = 25, RULE_postdot = 26, RULE_callinvoke = 27,
         RULE_fieldaccess = 28, RULE_braceaccess = 29, RULE_arrayinitializer = 30, RULE_listinitializer = 31, RULE_mapinitializer = 32,
         RULE_maptoken = 33, RULE_arguments = 34, RULE_argument = 35, RULE_lambda = 36, RULE_lamtype = 37, RULE_funcref = 38;
-    public static final String[] ruleNames = {
-        "source",
-        "function",
-        "parameters",
-        "statement",
-        "rstatement",
-        "dstatement",
-        "trailer",
-        "block",
-        "empty",
-        "initializer",
-        "afterthought",
-        "declaration",
-        "decltype",
-        "type",
-        "declvar",
-        "trap",
-        "noncondexpression",
-        "expression",
-        "unary",
-        "unarynotaddsub",
-        "castexpression",
-        "primordefcasttype",
-        "refcasttype",
-        "chain",
-        "primary",
-        "postfix",
-        "postdot",
-        "callinvoke",
-        "fieldaccess",
-        "braceaccess",
-        "arrayinitializer",
-        "listinitializer",
-        "mapinitializer",
-        "maptoken",
-        "arguments",
-        "argument",
-        "lambda",
-        "lamtype",
-        "funcref" };
-
-    private static final String[] _LITERAL_NAMES = {
-        null,
-        null,
-        null,
-        "'{'",
-        "'}'",
-        "'['",
-        "']'",
-        "'('",
-        "')'",
-        "'.'",
-        "'?.'",
-        "','",
-        "';'",
-        "'if'",
-        "'in'",
-        "'else'",
-        "'while'",
-        "'do'",
-        "'for'",
-        "'continue'",
-        "'break'",
-        "'return'",
-        "'new'",
-        "'try'",
-        "'catch'",
-        "'throw'",
-        "'this'",
-        "'instanceof'",
-        "'!'",
-        "'~'",
-        "'*'",
-        "'/'",
-        "'%'",
-        "'+'",
-        "'-'",
-        "'<<'",
-        "'>>'",
-        "'>>>'",
-        "'<'",
-        "'<='",
-        "'>'",
-        "'>='",
-        "'=='",
-        "'==='",
-        "'!='",
-        "'!=='",
-        "'&'",
-        "'^'",
-        "'|'",
-        "'&&'",
-        "'||'",
-        "'?'",
-        "':'",
-        "'?:'",
-        "'::'",
-        "'->'",
-        "'=~'",
-        "'==~'",
-        "'++'",
-        "'--'",
-        "'='",
-        "'+='",
-        "'-='",
-        "'*='",
-        "'/='",
-        "'%='",
-        "'&='",
-        "'^='",
-        "'|='",
-        "'<<='",
-        "'>>='",
-        "'>>>='",
-        null,
-        null,
-        null,
-        null,
-        null,
-        null,
-        "'true'",
-        "'false'",
-        "'null'",
-        null,
-        "'def'" };
-    private static final String[] _SYMBOLIC_NAMES = {
-        null,
-        "WS",
-        "COMMENT",
-        "LBRACK",
-        "RBRACK",
-        "LBRACE",
-        "RBRACE",
-        "LP",
-        "RP",
-        "DOT",
-        "NSDOT",
-        "COMMA",
-        "SEMICOLON",
-        "IF",
-        "IN",
-        "ELSE",
-        "WHILE",
-        "DO",
-        "FOR",
-        "CONTINUE",
-        "BREAK",
-        "RETURN",
-        "NEW",
-        "TRY",
-        "CATCH",
-        "THROW",
-        "THIS",
-        "INSTANCEOF",
-        "BOOLNOT",
-        "BWNOT",
-        "MUL",
-        "DIV",
-        "REM",
-        "ADD",
-        "SUB",
-        "LSH",
-        "RSH",
-        "USH",
-        "LT",
-        "LTE",
-        "GT",
-        "GTE",
-        "EQ",
-        "EQR",
-        "NE",
-        "NER",
-        "BWAND",
-        "XOR",
-        "BWOR",
-        "BOOLAND",
-        "BOOLOR",
-        "COND",
-        "COLON",
-        "ELVIS",
-        "REF",
-        "ARROW",
-        "FIND",
-        "MATCH",
-        "INCR",
-        "DECR",
-        "ASSIGN",
-        "AADD",
-        "ASUB",
-        "AMUL",
-        "ADIV",
-        "AREM",
-        "AAND",
-        "AXOR",
-        "AOR",
-        "ALSH",
-        "ARSH",
-        "AUSH",
-        "OCTAL",
-        "HEX",
-        "INTEGER",
-        "DECIMAL",
-        "STRING",
-        "REGEX",
-        "TRUE",
-        "FALSE",
-        "NULL",
-        "PRIMITIVE",
-        "DEF",
-        "ID",
-        "DOTINTEGER",
-        "DOTID" };
+
+    private static String[] makeRuleNames() {
+        return new String[] {
+            "source",
+            "function",
+            "parameters",
+            "statement",
+            "rstatement",
+            "dstatement",
+            "trailer",
+            "block",
+            "empty",
+            "initializer",
+            "afterthought",
+            "declaration",
+            "decltype",
+            "type",
+            "declvar",
+            "trap",
+            "noncondexpression",
+            "expression",
+            "unary",
+            "unarynotaddsub",
+            "castexpression",
+            "primordefcasttype",
+            "refcasttype",
+            "chain",
+            "primary",
+            "postfix",
+            "postdot",
+            "callinvoke",
+            "fieldaccess",
+            "braceaccess",
+            "arrayinitializer",
+            "listinitializer",
+            "mapinitializer",
+            "maptoken",
+            "arguments",
+            "argument",
+            "lambda",
+            "lamtype",
+            "funcref" };
+    }
+
+    public static final String[] ruleNames = makeRuleNames();
+
+    private static String[] makeLiteralNames() {
+        return new String[] {
+            null,
+            null,
+            null,
+            "'{'",
+            "'}'",
+            "'['",
+            "']'",
+            "'('",
+            "')'",
+            "'.'",
+            "'?.'",
+            "','",
+            "';'",
+            "'if'",
+            "'in'",
+            "'else'",
+            "'while'",
+            "'do'",
+            "'for'",
+            "'continue'",
+            "'break'",
+            "'return'",
+            "'new'",
+            "'try'",
+            "'catch'",
+            "'throw'",
+            "'this'",
+            "'instanceof'",
+            "'!'",
+            "'~'",
+            "'*'",
+            "'/'",
+            "'%'",
+            "'+'",
+            "'-'",
+            "'<<'",
+            "'>>'",
+            "'>>>'",
+            "'<'",
+            "'<='",
+            "'>'",
+            "'>='",
+            "'=='",
+            "'==='",
+            "'!='",
+            "'!=='",
+            "'&'",
+            "'^'",
+            "'|'",
+            "'&&'",
+            "'||'",
+            "'?'",
+            "':'",
+            "'?:'",
+            "'::'",
+            "'->'",
+            "'=~'",
+            "'==~'",
+            "'++'",
+            "'--'",
+            "'='",
+            "'+='",
+            "'-='",
+            "'*='",
+            "'/='",
+            "'%='",
+            "'&='",
+            "'^='",
+            "'|='",
+            "'<<='",
+            "'>>='",
+            "'>>>='",
+            null,
+            null,
+            null,
+            null,
+            null,
+            null,
+            "'true'",
+            "'false'",
+            "'null'",
+            null,
+            "'def'" };
+    }
+
+    private static final String[] _LITERAL_NAMES = makeLiteralNames();
+
+    private static String[] makeSymbolicNames() {
+        return new String[] {
+            null,
+            "WS",
+            "COMMENT",
+            "LBRACK",
+            "RBRACK",
+            "LBRACE",
+            "RBRACE",
+            "LP",
+            "RP",
+            "DOT",
+            "NSDOT",
+            "COMMA",
+            "SEMICOLON",
+            "IF",
+            "IN",
+            "ELSE",
+            "WHILE",
+            "DO",
+            "FOR",
+            "CONTINUE",
+            "BREAK",
+            "RETURN",
+            "NEW",
+            "TRY",
+            "CATCH",
+            "THROW",
+            "THIS",
+            "INSTANCEOF",
+            "BOOLNOT",
+            "BWNOT",
+            "MUL",
+            "DIV",
+            "REM",
+            "ADD",
+            "SUB",
+            "LSH",
+            "RSH",
+            "USH",
+            "LT",
+            "LTE",
+            "GT",
+            "GTE",
+            "EQ",
+            "EQR",
+            "NE",
+            "NER",
+            "BWAND",
+            "XOR",
+            "BWOR",
+            "BOOLAND",
+            "BOOLOR",
+            "COND",
+            "COLON",
+            "ELVIS",
+            "REF",
+            "ARROW",
+            "FIND",
+            "MATCH",
+            "INCR",
+            "DECR",
+            "ASSIGN",
+            "AADD",
+            "ASUB",
+            "AMUL",
+            "ADIV",
+            "AREM",
+            "AAND",
+            "AXOR",
+            "AOR",
+            "ALSH",
+            "ARSH",
+            "AUSH",
+            "OCTAL",
+            "HEX",
+            "INTEGER",
+            "DECIMAL",
+            "STRING",
+            "REGEX",
+            "TRUE",
+            "FALSE",
+            "NULL",
+            "PRIMITIVE",
+            "DEF",
+            "ID",
+            "DOTINTEGER",
+            "DOTID" };
+    }
+
+    private static final String[] _SYMBOLIC_NAMES = makeSymbolicNames();
     public static final Vocabulary VOCABULARY = new VocabularyImpl(_LITERAL_NAMES, _SYMBOLIC_NAMES);
 
     /**
@@ -310,7 +337,7 @@ public Vocabulary getVocabulary() {
 
     @Override
     public String getGrammarFileName() {
-        return "PainlessParser.g4";
+        return "java-escape";
     }
 
     @Override
@@ -333,6 +360,7 @@ public PainlessParser(TokenStream input) {
         _interp = new ParserATNSimulator(this, _ATN, _decisionToDFA, _sharedContextCache);
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class SourceContext extends ParserRuleContext {
         public TerminalNode EOF() {
             return getToken(PainlessParser.EOF, 0);
@@ -397,14 +425,8 @@ public final SourceContext source() throws RecognitionException {
                 setState(87);
                 _errHandler.sync(this);
                 _la = _input.LA(1);
-                while ((((_la) & ~0x3f) == 0
-                    && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << IF) | (1L << WHILE) | (1L << DO) | (1L << FOR) | (1L
-                        << CONTINUE) | (1L << BREAK) | (1L << RETURN) | (1L << NEW) | (1L << TRY) | (1L << THROW) | (1L << BOOLNOT) | (1L
-                            << BWNOT) | (1L << ADD) | (1L << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                    || ((((_la - 72)) & ~0x3f) == 0
-                        && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                            - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                << (NULL - 72)) | (1L << (PRIMITIVE - 72)) | (1L << (DEF - 72)) | (1L << (ID - 72)))) != 0)) {
+                while (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155080519840L) != 0
+                    || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 4095L) != 0) {
                     {
                         {
                             setState(84);
@@ -428,6 +450,7 @@ public final SourceContext source() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class FunctionContext extends ParserRuleContext {
         public DecltypeContext decltype() {
             return getRuleContext(DecltypeContext.class, 0);
@@ -486,6 +509,7 @@ public final FunctionContext function() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ParametersContext extends ParserRuleContext {
         public TerminalNode LP() {
             return getToken(PainlessParser.LP, 0);
@@ -545,9 +569,9 @@ public final ParametersContext parameters() throws RecognitionException {
                 setState(97);
                 match(LP);
                 setState(109);
+                _errHandler.sync(this);
                 _la = _input.LA(1);
-                if (((((_la - 81)) & ~0x3f) == 0
-                    && ((1L << (_la - 81)) & ((1L << (PRIMITIVE - 81)) | (1L << (DEF - 81)) | (1L << (ID - 81)))) != 0)) {
+                if ((((_la - 81)) & ~0x3f) == 0 && ((1L << (_la - 81)) & 7L) != 0) {
                     {
                         setState(98);
                         decltype();
@@ -587,6 +611,7 @@ public final ParametersContext parameters() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class StatementContext extends ParserRuleContext {
         public RstatementContext rstatement() {
             return getRuleContext(RstatementContext.class, 0);
@@ -626,6 +651,7 @@ public final StatementContext statement() throws RecognitionException {
         int _la;
         try {
             setState(117);
+            _errHandler.sync(this);
             switch (_input.LA(1)) {
                 case IF:
                 case WHILE:
@@ -670,6 +696,8 @@ public final StatementContext statement() throws RecognitionException {
                     if (!(_la == EOF || _la == SEMICOLON)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                 }
@@ -687,6 +715,7 @@ public final StatementContext statement() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class RstatementContext extends ParserRuleContext {
         public RstatementContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -704,6 +733,7 @@ public void copyFrom(RstatementContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ForContext extends RstatementContext {
         public TerminalNode FOR() {
             return getToken(PainlessParser.FOR, 0);
@@ -756,6 +786,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class TryContext extends RstatementContext {
         public TerminalNode TRY() {
             return getToken(PainlessParser.TRY, 0);
@@ -784,6 +815,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class WhileContext extends RstatementContext {
         public TerminalNode WHILE() {
             return getToken(PainlessParser.WHILE, 0);
@@ -820,6 +852,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class IneachContext extends RstatementContext {
         public TerminalNode FOR() {
             return getToken(PainlessParser.FOR, 0);
@@ -860,6 +893,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class IfContext extends RstatementContext {
         public TerminalNode IF() {
             return getToken(PainlessParser.IF, 0);
@@ -900,6 +934,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class EachContext extends RstatementContext {
         public TerminalNode FOR() {
             return getToken(PainlessParser.FOR, 0);
@@ -996,6 +1031,7 @@ public final RstatementContext rstatement() throws RecognitionException {
                     setState(132);
                     match(RP);
                     setState(135);
+                    _errHandler.sync(this);
                     switch (_input.LA(1)) {
                         case LBRACK:
                         case LBRACE:
@@ -1050,14 +1086,10 @@ public final RstatementContext rstatement() throws RecognitionException {
                     setState(138);
                     match(LP);
                     setState(140);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L
-                            << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (PRIMITIVE - 72)) | (1L << (DEF - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155034439840L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 4095L) != 0) {
                         {
                             setState(139);
                             initializer();
@@ -1067,14 +1099,10 @@ public final RstatementContext rstatement() throws RecognitionException {
                     setState(142);
                     match(SEMICOLON);
                     setState(144);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L
-                            << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155034439840L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 2559L) != 0) {
                         {
                             setState(143);
                             expression();
@@ -1084,14 +1112,10 @@ public final RstatementContext rstatement() throws RecognitionException {
                     setState(146);
                     match(SEMICOLON);
                     setState(148);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L
-                            << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155034439840L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 2559L) != 0) {
                         {
                             setState(147);
                             afterthought();
@@ -1101,6 +1125,7 @@ public final RstatementContext rstatement() throws RecognitionException {
                     setState(150);
                     match(RP);
                     setState(153);
+                    _errHandler.sync(this);
                     switch (_input.LA(1)) {
                         case LBRACK:
                         case LBRACE:
@@ -1226,6 +1251,7 @@ public final RstatementContext rstatement() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DstatementContext extends ParserRuleContext {
         public DstatementContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -1243,6 +1269,7 @@ public void copyFrom(DstatementContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DeclContext extends DstatementContext {
         public DeclarationContext declaration() {
             return getRuleContext(DeclarationContext.class, 0);
@@ -1259,6 +1286,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class BreakContext extends DstatementContext {
         public TerminalNode BREAK() {
             return getToken(PainlessParser.BREAK, 0);
@@ -1275,6 +1303,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ThrowContext extends DstatementContext {
         public TerminalNode THROW() {
             return getToken(PainlessParser.THROW, 0);
@@ -1295,6 +1324,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ContinueContext extends DstatementContext {
         public TerminalNode CONTINUE() {
             return getToken(PainlessParser.CONTINUE, 0);
@@ -1311,6 +1341,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ExprContext extends DstatementContext {
         public ExpressionContext expression() {
             return getRuleContext(ExpressionContext.class, 0);
@@ -1327,6 +1358,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DoContext extends DstatementContext {
         public TerminalNode DO() {
             return getToken(PainlessParser.DO, 0);
@@ -1363,6 +1395,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ReturnContext extends DstatementContext {
         public TerminalNode RETURN() {
             return getToken(PainlessParser.RETURN, 0);
@@ -1435,14 +1468,10 @@ public final DstatementContext dstatement() throws RecognitionException {
                     setState(191);
                     match(RETURN);
                     setState(193);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L
-                            << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155034439840L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 2559L) != 0) {
                         {
                             setState(192);
                             expression();
@@ -1478,6 +1507,7 @@ public final DstatementContext dstatement() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class TrailerContext extends ParserRuleContext {
         public BlockContext block() {
             return getRuleContext(BlockContext.class, 0);
@@ -1508,6 +1538,7 @@ public final TrailerContext trailer() throws RecognitionException {
         enterRule(_localctx, 12, RULE_trailer);
         try {
             setState(202);
+            _errHandler.sync(this);
             switch (_input.LA(1)) {
                 case LBRACK:
                     enterOuterAlt(_localctx, 1); {
@@ -1563,6 +1594,7 @@ public final TrailerContext trailer() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class BlockContext extends ParserRuleContext {
         public TerminalNode LBRACK() {
             return getToken(PainlessParser.LBRACK, 0);
@@ -1627,15 +1659,10 @@ public final BlockContext block() throws RecognitionException {
                     _alt = getInterpreter().adaptivePredict(_input, 16, _ctx);
                 }
                 setState(212);
+                _errHandler.sync(this);
                 _la = _input.LA(1);
-                if ((((_la) & ~0x3f) == 0
-                    && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << DO) | (1L << CONTINUE) | (1L << BREAK) | (1L << RETURN) | (1L
-                        << NEW) | (1L << THROW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L << SUB) | (1L << INCR) | (1L
-                            << DECR))) != 0)
-                    || ((((_la - 72)) & ~0x3f) == 0
-                        && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                            - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                << (NULL - 72)) | (1L << (PRIMITIVE - 72)) | (1L << (DEF - 72)) | (1L << (ID - 72)))) != 0)) {
+                if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155071795360L) != 0
+                    || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 4095L) != 0) {
                     {
                         setState(211);
                         dstatement();
@@ -1655,6 +1682,7 @@ public final BlockContext block() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class EmptyContext extends ParserRuleContext {
         public TerminalNode SEMICOLON() {
             return getToken(PainlessParser.SEMICOLON, 0);
@@ -1695,6 +1723,7 @@ public final EmptyContext empty() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class InitializerContext extends ParserRuleContext {
         public DeclarationContext declaration() {
             return getRuleContext(DeclarationContext.class, 0);
@@ -1750,6 +1779,7 @@ public final InitializerContext initializer() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class AfterthoughtContext extends ParserRuleContext {
         public ExpressionContext expression() {
             return getRuleContext(ExpressionContext.class, 0);
@@ -1790,6 +1820,7 @@ public final AfterthoughtContext afterthought() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DeclarationContext extends ParserRuleContext {
         public DecltypeContext decltype() {
             return getRuleContext(DecltypeContext.class, 0);
@@ -1865,6 +1896,7 @@ public final DeclarationContext declaration() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DecltypeContext extends ParserRuleContext {
         public TypeContext type() {
             return getRuleContext(TypeContext.class, 0);
@@ -1940,6 +1972,7 @@ public final DecltypeContext decltype() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class TypeContext extends ParserRuleContext {
         public TerminalNode DEF() {
             return getToken(PainlessParser.DEF, 0);
@@ -1991,6 +2024,7 @@ public final TypeContext type() throws RecognitionException {
         try {
             int _alt;
             setState(251);
+            _errHandler.sync(this);
             switch (_input.LA(1)) {
                 case DEF:
                     enterOuterAlt(_localctx, 1); {
@@ -2041,6 +2075,7 @@ public final TypeContext type() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DeclvarContext extends ParserRuleContext {
         public TerminalNode ID() {
             return getToken(PainlessParser.ID, 0);
@@ -2080,6 +2115,7 @@ public final DeclvarContext declvar() throws RecognitionException {
                 setState(253);
                 match(ID);
                 setState(256);
+                _errHandler.sync(this);
                 _la = _input.LA(1);
                 if (_la == ASSIGN) {
                     {
@@ -2101,6 +2137,7 @@ public final DeclvarContext declvar() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class TrapContext extends ParserRuleContext {
         public TerminalNode CATCH() {
             return getToken(PainlessParser.CATCH, 0);
@@ -2171,6 +2208,7 @@ public final TrapContext trap() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NoncondexpressionContext extends ParserRuleContext {
         public NoncondexpressionContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -2188,6 +2226,7 @@ public void copyFrom(NoncondexpressionContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class SingleContext extends NoncondexpressionContext {
         public UnaryContext unary() {
             return getRuleContext(UnaryContext.class, 0);
@@ -2204,6 +2243,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class CompContext extends NoncondexpressionContext {
         public List<NoncondexpressionContext> noncondexpression() {
             return getRuleContexts(NoncondexpressionContext.class);
@@ -2256,6 +2296,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class BoolContext extends NoncondexpressionContext {
         public List<NoncondexpressionContext> noncondexpression() {
             return getRuleContexts(NoncondexpressionContext.class);
@@ -2284,6 +2325,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class BinaryContext extends NoncondexpressionContext {
         public List<NoncondexpressionContext> noncondexpression() {
             return getRuleContexts(NoncondexpressionContext.class);
@@ -2356,6 +2398,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ElvisContext extends NoncondexpressionContext {
         public List<NoncondexpressionContext> noncondexpression() {
             return getRuleContexts(NoncondexpressionContext.class);
@@ -2380,6 +2423,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class InstanceofContext extends NoncondexpressionContext {
         public NoncondexpressionContext noncondexpression() {
             return getRuleContext(NoncondexpressionContext.class, 0);
@@ -2447,9 +2491,11 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(precpred(_ctx, 13))) throw new FailedPredicateException(this, "precpred(_ctx, 13)");
                                     setState(269);
                                     _la = _input.LA(1);
-                                    if (!((((_la) & ~0x3f) == 0 && ((1L << _la) & ((1L << MUL) | (1L << DIV) | (1L << REM))) != 0))) {
+                                    if (!(((_la) & ~0x3f) == 0 && ((1L << _la) & 7516192768L) != 0)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(270);
@@ -2466,6 +2512,8 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(_la == ADD || _la == SUB)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(273);
@@ -2482,6 +2530,8 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(_la == FIND || _la == MATCH)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(276);
@@ -2495,9 +2545,11 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(precpred(_ctx, 10))) throw new FailedPredicateException(this, "precpred(_ctx, 10)");
                                     setState(278);
                                     _la = _input.LA(1);
-                                    if (!((((_la) & ~0x3f) == 0 && ((1L << _la) & ((1L << LSH) | (1L << RSH) | (1L << USH))) != 0))) {
+                                    if (!(((_la) & ~0x3f) == 0 && ((1L << _la) & 240518168576L) != 0)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(279);
@@ -2511,10 +2563,11 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(precpred(_ctx, 9))) throw new FailedPredicateException(this, "precpred(_ctx, 9)");
                                     setState(281);
                                     _la = _input.LA(1);
-                                    if (!((((_la) & ~0x3f) == 0
-                                        && ((1L << _la) & ((1L << LT) | (1L << LTE) | (1L << GT) | (1L << GTE))) != 0))) {
+                                    if (!(((_la) & ~0x3f) == 0 && ((1L << _la) & 4123168604160L) != 0)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(282);
@@ -2528,10 +2581,11 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
                                     if (!(precpred(_ctx, 7))) throw new FailedPredicateException(this, "precpred(_ctx, 7)");
                                     setState(284);
                                     _la = _input.LA(1);
-                                    if (!((((_la) & ~0x3f) == 0
-                                        && ((1L << _la) & ((1L << EQ) | (1L << EQR) | (1L << NE) | (1L << NER))) != 0))) {
+                                    if (!(((_la) & ~0x3f) == 0 && ((1L << _la) & 65970697666560L) != 0)) {
                                         _errHandler.recoverInline(this);
                                     } else {
+                                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                                        _errHandler.reportMatch(this);
                                         consume();
                                     }
                                     setState(285);
@@ -2633,6 +2687,7 @@ private NoncondexpressionContext noncondexpression(int _p) throws RecognitionExc
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ExpressionContext extends ParserRuleContext {
         public ExpressionContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -2650,6 +2705,7 @@ public void copyFrom(ExpressionContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ConditionalContext extends ExpressionContext {
         public NoncondexpressionContext noncondexpression() {
             return getRuleContext(NoncondexpressionContext.class, 0);
@@ -2682,6 +2738,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class AssignmentContext extends ExpressionContext {
         public NoncondexpressionContext noncondexpression() {
             return getRuleContext(NoncondexpressionContext.class, 0);
@@ -2750,6 +2807,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NonconditionalContext extends ExpressionContext {
         public NoncondexpressionContext noncondexpression() {
             return getRuleContext(NoncondexpressionContext.class, 0);
@@ -2803,12 +2861,11 @@ public final ExpressionContext expression() throws RecognitionException {
                     noncondexpression(0);
                     setState(320);
                     _la = _input.LA(1);
-                    if (!(((((_la - 60)) & ~0x3f) == 0
-                        && ((1L << (_la - 60)) & ((1L << (ASSIGN - 60)) | (1L << (AADD - 60)) | (1L << (ASUB - 60)) | (1L << (AMUL - 60))
-                            | (1L << (ADIV - 60)) | (1L << (AREM - 60)) | (1L << (AAND - 60)) | (1L << (AXOR - 60)) | (1L << (AOR - 60))
-                            | (1L << (ALSH - 60)) | (1L << (ARSH - 60)) | (1L << (AUSH - 60)))) != 0))) {
+                    if (!((((_la - 60)) & ~0x3f) == 0 && ((1L << (_la - 60)) & 4095L) != 0)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                     setState(321);
@@ -2826,6 +2883,7 @@ public final ExpressionContext expression() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class UnaryContext extends ParserRuleContext {
         public UnaryContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -2843,6 +2901,7 @@ public void copyFrom(UnaryContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NotaddsubContext extends UnaryContext {
         public UnarynotaddsubContext unarynotaddsub() {
             return getRuleContext(UnarynotaddsubContext.class, 0);
@@ -2859,6 +2918,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PreContext extends UnaryContext {
         public ChainContext chain() {
             return getRuleContext(ChainContext.class, 0);
@@ -2883,6 +2943,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class AddsubContext extends UnaryContext {
         public UnaryContext unary() {
             return getRuleContext(UnaryContext.class, 0);
@@ -2913,6 +2974,7 @@ public final UnaryContext unary() throws RecognitionException {
         int _la;
         try {
             setState(330);
+            _errHandler.sync(this);
             switch (_input.LA(1)) {
                 case INCR:
                 case DECR:
@@ -2923,6 +2985,8 @@ public final UnaryContext unary() throws RecognitionException {
                     if (!(_la == INCR || _la == DECR)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                     setState(326);
@@ -2938,6 +3002,8 @@ public final UnaryContext unary() throws RecognitionException {
                     if (!(_la == ADD || _la == SUB)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                     setState(328);
@@ -2978,6 +3044,7 @@ public final UnaryContext unary() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class UnarynotaddsubContext extends ParserRuleContext {
         public UnarynotaddsubContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -2995,6 +3062,7 @@ public void copyFrom(UnarynotaddsubContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class CastContext extends UnarynotaddsubContext {
         public CastexpressionContext castexpression() {
             return getRuleContext(CastexpressionContext.class, 0);
@@ -3011,6 +3079,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NotContext extends UnarynotaddsubContext {
         public UnaryContext unary() {
             return getRuleContext(UnaryContext.class, 0);
@@ -3035,6 +3104,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ReadContext extends UnarynotaddsubContext {
         public ChainContext chain() {
             return getRuleContext(ChainContext.class, 0);
@@ -3051,6 +3121,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PostContext extends UnarynotaddsubContext {
         public ChainContext chain() {
             return getRuleContext(ChainContext.class, 0);
@@ -3100,6 +3171,8 @@ public final UnarynotaddsubContext unarynotaddsub() throws RecognitionException
                     if (!(_la == INCR || _la == DECR)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                 }
@@ -3112,6 +3185,8 @@ public final UnarynotaddsubContext unarynotaddsub() throws RecognitionException
                     if (!(_la == BOOLNOT || _la == BWNOT)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                     setState(337);
@@ -3136,6 +3211,7 @@ public final UnarynotaddsubContext unarynotaddsub() throws RecognitionException
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class CastexpressionContext extends ParserRuleContext {
         public CastexpressionContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -3153,6 +3229,7 @@ public void copyFrom(CastexpressionContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class RefcastContext extends CastexpressionContext {
         public TerminalNode LP() {
             return getToken(PainlessParser.LP, 0);
@@ -3181,6 +3258,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PrimordefcastContext extends CastexpressionContext {
         public TerminalNode LP() {
             return getToken(PainlessParser.LP, 0);
@@ -3253,6 +3331,7 @@ public final CastexpressionContext castexpression() throws RecognitionException
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PrimordefcasttypeContext extends ParserRuleContext {
         public TerminalNode DEF() {
             return getToken(PainlessParser.DEF, 0);
@@ -3292,6 +3371,8 @@ public final PrimordefcasttypeContext primordefcasttype() throws RecognitionExce
                 if (!(_la == PRIMITIVE || _la == DEF)) {
                     _errHandler.recoverInline(this);
                 } else {
+                    if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                    _errHandler.reportMatch(this);
                     consume();
                 }
             }
@@ -3305,6 +3386,7 @@ public final PrimordefcasttypeContext primordefcasttype() throws RecognitionExce
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class RefcasttypeContext extends ParserRuleContext {
         public TerminalNode DEF() {
             return getToken(PainlessParser.DEF, 0);
@@ -3372,6 +3454,7 @@ public final RefcasttypeContext refcasttype() throws RecognitionException {
         int _la;
         try {
             setState(384);
+            _errHandler.sync(this);
             switch (_input.LA(1)) {
                 case DEF:
                     enterOuterAlt(_localctx, 1); {
@@ -3468,6 +3551,7 @@ public final RefcasttypeContext refcasttype() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ChainContext extends ParserRuleContext {
         public ChainContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -3485,6 +3569,7 @@ public void copyFrom(ChainContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class DynamicContext extends ChainContext {
         public PrimaryContext primary() {
             return getRuleContext(PrimaryContext.class, 0);
@@ -3509,6 +3594,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NewarrayContext extends ChainContext {
         public ArrayinitializerContext arrayinitializer() {
             return getRuleContext(ArrayinitializerContext.class, 0);
@@ -3574,6 +3660,7 @@ public final ChainContext chain() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PrimaryContext extends ParserRuleContext {
         public PrimaryContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -3591,6 +3678,7 @@ public void copyFrom(PrimaryContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ListinitContext extends PrimaryContext {
         public ListinitializerContext listinitializer() {
             return getRuleContext(ListinitializerContext.class, 0);
@@ -3607,6 +3695,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class RegexContext extends PrimaryContext {
         public TerminalNode REGEX() {
             return getToken(PainlessParser.REGEX, 0);
@@ -3623,6 +3712,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NullContext extends PrimaryContext {
         public TerminalNode NULL() {
             return getToken(PainlessParser.NULL, 0);
@@ -3639,6 +3729,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class StringContext extends PrimaryContext {
         public TerminalNode STRING() {
             return getToken(PainlessParser.STRING, 0);
@@ -3655,6 +3746,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class MapinitContext extends PrimaryContext {
         public MapinitializerContext mapinitializer() {
             return getRuleContext(MapinitializerContext.class, 0);
@@ -3671,6 +3763,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class CalllocalContext extends PrimaryContext {
         public TerminalNode ID() {
             return getToken(PainlessParser.ID, 0);
@@ -3691,6 +3784,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class TrueContext extends PrimaryContext {
         public TerminalNode TRUE() {
             return getToken(PainlessParser.TRUE, 0);
@@ -3707,6 +3801,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class FalseContext extends PrimaryContext {
         public TerminalNode FALSE() {
             return getToken(PainlessParser.FALSE, 0);
@@ -3723,6 +3818,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class VariableContext extends PrimaryContext {
         public TerminalNode ID() {
             return getToken(PainlessParser.ID, 0);
@@ -3739,6 +3835,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NumericContext extends PrimaryContext {
         public TerminalNode OCTAL() {
             return getToken(PainlessParser.OCTAL, 0);
@@ -3767,6 +3864,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NewobjectContext extends PrimaryContext {
         public TerminalNode NEW() {
             return getToken(PainlessParser.NEW, 0);
@@ -3791,6 +3889,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PrecedenceContext extends PrimaryContext {
         public TerminalNode LP() {
             return getToken(PainlessParser.LP, 0);
@@ -3839,11 +3938,11 @@ public final PrimaryContext primary() throws RecognitionException {
                     enterOuterAlt(_localctx, 2); {
                     setState(400);
                     _la = _input.LA(1);
-                    if (!(((((_la - 72)) & ~0x3f) == 0
-                        && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                            - 72)))) != 0))) {
+                    if (!((((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 15L) != 0)) {
                         _errHandler.recoverInline(this);
                     } else {
+                        if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                        _errHandler.reportMatch(this);
                         consume();
                     }
                 }
@@ -3935,6 +4034,7 @@ public final PrimaryContext primary() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PostfixContext extends ParserRuleContext {
         public CallinvokeContext callinvoke() {
             return getRuleContext(CallinvokeContext.class, 0);
@@ -4000,6 +4100,7 @@ public final PostfixContext postfix() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class PostdotContext extends ParserRuleContext {
         public CallinvokeContext callinvoke() {
             return getRuleContext(CallinvokeContext.class, 0);
@@ -4055,6 +4156,7 @@ public final PostdotContext postdot() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class CallinvokeContext extends ParserRuleContext {
         public TerminalNode DOTID() {
             return getToken(PainlessParser.DOTID, 0);
@@ -4100,6 +4202,8 @@ public final CallinvokeContext callinvoke() throws RecognitionException {
                 if (!(_la == DOT || _la == NSDOT)) {
                     _errHandler.recoverInline(this);
                 } else {
+                    if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                    _errHandler.reportMatch(this);
                     consume();
                 }
                 setState(427);
@@ -4117,6 +4221,7 @@ public final CallinvokeContext callinvoke() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class FieldaccessContext extends ParserRuleContext {
         public TerminalNode DOT() {
             return getToken(PainlessParser.DOT, 0);
@@ -4162,6 +4267,8 @@ public final FieldaccessContext fieldaccess() throws RecognitionException {
                 if (!(_la == DOT || _la == NSDOT)) {
                     _errHandler.recoverInline(this);
                 } else {
+                    if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                    _errHandler.reportMatch(this);
                     consume();
                 }
                 setState(431);
@@ -4169,6 +4276,8 @@ public final FieldaccessContext fieldaccess() throws RecognitionException {
                 if (!(_la == DOTINTEGER || _la == DOTID)) {
                     _errHandler.recoverInline(this);
                 } else {
+                    if (_input.LA(1) == Token.EOF) matchedEOF = true;
+                    _errHandler.reportMatch(this);
                     consume();
                 }
             }
@@ -4182,6 +4291,7 @@ public final FieldaccessContext fieldaccess() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class BraceaccessContext extends ParserRuleContext {
         public TerminalNode LBRACE() {
             return getToken(PainlessParser.LBRACE, 0);
@@ -4234,6 +4344,7 @@ public final BraceaccessContext braceaccess() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ArrayinitializerContext extends ParserRuleContext {
         public ArrayinitializerContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -4251,6 +4362,7 @@ public void copyFrom(ArrayinitializerContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NewstandardarrayContext extends ArrayinitializerContext {
         public TerminalNode NEW() {
             return getToken(PainlessParser.NEW, 0);
@@ -4307,6 +4419,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class NewinitializedarrayContext extends ArrayinitializerContext {
         public TerminalNode NEW() {
             return getToken(PainlessParser.NEW, 0);
@@ -4449,14 +4562,10 @@ public final ArrayinitializerContext arrayinitializer() throws RecognitionExcept
                     setState(460);
                     match(LBRACK);
                     setState(469);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << BOOLNOT) | (1L << BWNOT) | (1L << ADD) | (1L
-                            << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155034439840L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 2559L) != 0) {
                         {
                             setState(461);
                             expression();
@@ -4510,6 +4619,7 @@ public final ArrayinitializerContext arrayinitializer() throws RecognitionExcept
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ListinitializerContext extends ParserRuleContext {
         public TerminalNode LBRACE() {
             return getToken(PainlessParser.LBRACE, 0);
@@ -4604,6 +4714,7 @@ public final ListinitializerContext listinitializer() throws RecognitionExceptio
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class MapinitializerContext extends ParserRuleContext {
         public TerminalNode LBRACE() {
             return getToken(PainlessParser.LBRACE, 0);
@@ -4704,6 +4815,7 @@ public final MapinitializerContext mapinitializer() throws RecognitionException
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class MaptokenContext extends ParserRuleContext {
         public List<ExpressionContext> expression() {
             return getRuleContexts(ExpressionContext.class);
@@ -4756,6 +4868,7 @@ public final MaptokenContext maptoken() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ArgumentsContext extends ParserRuleContext {
         public TerminalNode LP() {
             return getToken(PainlessParser.LP, 0);
@@ -4808,14 +4921,10 @@ public final ArgumentsContext arguments() throws RecognitionException {
                     setState(515);
                     match(LP);
                     setState(524);
+                    _errHandler.sync(this);
                     _la = _input.LA(1);
-                    if ((((_la) & ~0x3f) == 0
-                        && ((1L << _la) & ((1L << LBRACE) | (1L << LP) | (1L << NEW) | (1L << THIS) | (1L << BOOLNOT) | (1L << BWNOT) | (1L
-                            << ADD) | (1L << SUB) | (1L << INCR) | (1L << DECR))) != 0)
-                        || ((((_la - 72)) & ~0x3f) == 0
-                            && ((1L << (_la - 72)) & ((1L << (OCTAL - 72)) | (1L << (HEX - 72)) | (1L << (INTEGER - 72)) | (1L << (DECIMAL
-                                - 72)) | (1L << (STRING - 72)) | (1L << (REGEX - 72)) | (1L << (TRUE - 72)) | (1L << (FALSE - 72)) | (1L
-                                    << (NULL - 72)) | (1L << (PRIMITIVE - 72)) | (1L << (DEF - 72)) | (1L << (ID - 72)))) != 0)) {
+                    if (((_la) & ~0x3f) == 0 && ((1L << _la) & 864691155101548704L) != 0
+                        || (((_la - 72)) & ~0x3f) == 0 && ((1L << (_la - 72)) & 4095L) != 0) {
                         {
                             setState(516);
                             argument();
@@ -4852,6 +4961,7 @@ public final ArgumentsContext arguments() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ArgumentContext extends ParserRuleContext {
         public ExpressionContext expression() {
             return getRuleContext(ExpressionContext.class, 0);
@@ -4917,6 +5027,7 @@ public final ArgumentContext argument() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class LambdaContext extends ParserRuleContext {
         public TerminalNode ARROW() {
             return getToken(PainlessParser.ARROW, 0);
@@ -4978,6 +5089,7 @@ public final LambdaContext lambda() throws RecognitionException {
             enterOuterAlt(_localctx, 1);
             {
                 setState(546);
+                _errHandler.sync(this);
                 switch (_input.LA(1)) {
                     case PRIMITIVE:
                     case DEF:
@@ -4990,9 +5102,9 @@ public final LambdaContext lambda() throws RecognitionException {
                         setState(534);
                         match(LP);
                         setState(543);
+                        _errHandler.sync(this);
                         _la = _input.LA(1);
-                        if (((((_la - 81)) & ~0x3f) == 0
-                            && ((1L << (_la - 81)) & ((1L << (PRIMITIVE - 81)) | (1L << (DEF - 81)) | (1L << (ID - 81)))) != 0)) {
+                        if ((((_la - 81)) & ~0x3f) == 0 && ((1L << (_la - 81)) & 7L) != 0) {
                             {
                                 setState(535);
                                 lamtype();
@@ -5025,6 +5137,7 @@ public final LambdaContext lambda() throws RecognitionException {
                 setState(548);
                 match(ARROW);
                 setState(551);
+                _errHandler.sync(this);
                 switch (_input.LA(1)) {
                     case LBRACK: {
                         setState(549);
@@ -5068,6 +5181,7 @@ public final LambdaContext lambda() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class LamtypeContext extends ParserRuleContext {
         public TerminalNode ID() {
             return getToken(PainlessParser.ID, 0);
@@ -5121,6 +5235,7 @@ public final LamtypeContext lamtype() throws RecognitionException {
         return _localctx;
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class FuncrefContext extends ParserRuleContext {
         public FuncrefContext(ParserRuleContext parent, int invokingState) {
             super(parent, invokingState);
@@ -5138,6 +5253,7 @@ public void copyFrom(FuncrefContext ctx) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ClassfuncrefContext extends FuncrefContext {
         public DecltypeContext decltype() {
             return getRuleContext(DecltypeContext.class, 0);
@@ -5162,6 +5278,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class ConstructorfuncrefContext extends FuncrefContext {
         public DecltypeContext decltype() {
             return getRuleContext(DecltypeContext.class, 0);
@@ -5188,6 +5305,7 @@ public <T> T accept(ParseTreeVisitor<? extends T> visitor) {
         }
     }
 
+    @SuppressWarnings("CheckReturnValue")
     public static class LocalfuncrefContext extends FuncrefContext {
         public TerminalNode THIS() {
             return getToken(PainlessParser.THIS, 0);
@@ -5313,224 +5431,395 @@ private boolean noncondexpression_sempred(NoncondexpressionContext _localctx, in
         return true;
     }
 
-    public static final String _serializedATN = "\3\u0430\ud6d1\u8206\uad2d\u4417\uaef1\u8d80\uaadd\3W\u023e\4\2\t\2\4"
-        + "\3\t\3\4\4\t\4\4\5\t\5\4\6\t\6\4\7\t\7\4\b\t\b\4\t\t\t\4\n\t\n\4\13\t"
-        + "\13\4\f\t\f\4\r\t\r\4\16\t\16\4\17\t\17\4\20\t\20\4\21\t\21\4\22\t\22"
-        + "\4\23\t\23\4\24\t\24\4\25\t\25\4\26\t\26\4\27\t\27\4\30\t\30\4\31\t\31"
-        + "\4\32\t\32\4\33\t\33\4\34\t\34\4\35\t\35\4\36\t\36\4\37\t\37\4 \t \4!"
-        + "\t!\4\"\t\"\4#\t#\4$\t$\4%\t%\4&\t&\4\'\t\'\4(\t(\3\2\7\2R\n\2\f\2\16"
-        + "\2U\13\2\3\2\7\2X\n\2\f\2\16\2[\13\2\3\2\3\2\3\3\3\3\3\3\3\3\3\3\3\4\3"
-        + "\4\3\4\3\4\3\4\3\4\3\4\7\4k\n\4\f\4\16\4n\13\4\5\4p\n\4\3\4\3\4\3\5\3"
-        + "\5\3\5\3\5\5\5x\n\5\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\5\6\u0082\n\6\3\6"
-        + "\3\6\3\6\3\6\3\6\3\6\5\6\u008a\n\6\3\6\3\6\3\6\5\6\u008f\n\6\3\6\3\6\5"
-        + "\6\u0093\n\6\3\6\3\6\5\6\u0097\n\6\3\6\3\6\3\6\5\6\u009c\n\6\3\6\3\6\3"
-        + "\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6\3\6"
-        + "\6\6\u00b2\n\6\r\6\16\6\u00b3\5\6\u00b6\n\6\3\7\3\7\3\7\3\7\3\7\3\7\3"
-        + "\7\3\7\3\7\3\7\3\7\3\7\5\7\u00c4\n\7\3\7\3\7\3\7\5\7\u00c9\n\7\3\b\3\b"
-        + "\5\b\u00cd\n\b\3\t\3\t\7\t\u00d1\n\t\f\t\16\t\u00d4\13\t\3\t\5\t\u00d7"
-        + "\n\t\3\t\3\t\3\n\3\n\3\13\3\13\5\13\u00df\n\13\3\f\3\f\3\r\3\r\3\r\3\r"
-        + "\7\r\u00e7\n\r\f\r\16\r\u00ea\13\r\3\16\3\16\3\16\7\16\u00ef\n\16\f\16"
-        + "\16\16\u00f2\13\16\3\17\3\17\3\17\3\17\3\17\7\17\u00f9\n\17\f\17\16\17"
-        + "\u00fc\13\17\5\17\u00fe\n\17\3\20\3\20\3\20\5\20\u0103\n\20\3\21\3\21"
-        + "\3\21\3\21\3\21\3\21\3\21\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22"
-        + "\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22"
-        + "\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22\3\22"
-        + "\3\22\3\22\3\22\3\22\3\22\7\22\u0136\n\22\f\22\16\22\u0139\13\22\3\23"
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-        + "\36\3\36\3\36\3\37\3\37\3\37\3\37\3 \3 \3 \3 \3 \3 \6 \u01be\n \r \16"
-        + " \u01bf\3 \3 \7 \u01c4\n \f \16 \u01c7\13 \5 \u01c9\n \3 \3 \3 \3 \3 "
-        + "\3 \3 \3 \7 \u01d3\n \f \16 \u01d6\13 \5 \u01d8\n \3 \3 \7 \u01dc\n \f"
-        + " \16 \u01df\13 \5 \u01e1\n \3!\3!\3!\3!\7!\u01e7\n!\f!\16!\u01ea\13!\3"
-        + "!\3!\3!\3!\5!\u01f0\n!\3\"\3\"\3\"\3\"\7\"\u01f6\n\"\f\"\16\"\u01f9\13"
-        + "\"\3\"\3\"\3\"\3\"\3\"\5\"\u0200\n\"\3#\3#\3#\3#\3$\3$\3$\3$\7$\u020a"
-        + "\n$\f$\16$\u020d\13$\5$\u020f\n$\3$\3$\3%\3%\3%\5%\u0216\n%\3&\3&\3&\3"
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-        + "$\23\2\u0144\u0146\3\2\2\2\u0145\u013a\3\2\2\2\u0145\u013b\3\2\2\2\u0145"
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-        + "\u0165\3\2\2\2\u0182\u016c\3\2\2\2\u0182\u0173\3\2\2\2\u0183/\3\2\2\2"
-        + "\u0184\u0188\5\62\32\2\u0185\u0187\5\64\33\2\u0186\u0185\3\2\2\2\u0187"
-        + "\u018a\3\2\2\2\u0188\u0186\3\2\2\2\u0188\u0189\3\2\2\2\u0189\u018d\3\2"
-        + "\2\2\u018a\u0188\3\2\2\2\u018b\u018d\5> \2\u018c\u0184\3\2\2\2\u018c\u018b"
-        + "\3\2\2\2\u018d\61\3\2\2\2\u018e\u018f\7\t\2\2\u018f\u0190\5$\23\2\u0190"
-        + "\u0191\7\n\2\2\u0191\u01a2\3\2\2\2\u0192\u01a2\t\r\2\2\u0193\u01a2\7P"
-        + "\2\2\u0194\u01a2\7Q\2\2\u0195\u01a2\7R\2\2\u0196\u01a2\7N\2\2\u0197\u01a2"
-        + "\7O\2\2\u0198\u01a2\5@!\2\u0199\u01a2\5B\"\2\u019a\u01a2\7U\2\2\u019b"
-        + "\u019c\7U\2\2\u019c\u01a2\5F$\2\u019d\u019e\7\30\2\2\u019e\u019f\5\34"
-        + "\17\2\u019f\u01a0\5F$\2\u01a0\u01a2\3\2\2\2\u01a1\u018e\3\2\2\2\u01a1"
-        + "\u0192\3\2\2\2\u01a1\u0193\3\2\2\2\u01a1\u0194\3\2\2\2\u01a1\u0195\3\2"
-        + "\2\2\u01a1\u0196\3\2\2\2\u01a1\u0197\3\2\2\2\u01a1\u0198\3\2\2\2\u01a1"
-        + "\u0199\3\2\2\2\u01a1\u019a\3\2\2\2\u01a1\u019b\3\2\2\2\u01a1\u019d\3\2"
-        + "\2\2\u01a2\63\3\2\2\2\u01a3\u01a7\58\35\2\u01a4\u01a7\5:\36\2\u01a5\u01a7"
-        + "\5<\37\2\u01a6\u01a3\3\2\2\2\u01a6\u01a4\3\2\2\2\u01a6\u01a5\3\2\2\2\u01a7"
-        + "\65\3\2\2\2\u01a8\u01ab\58\35\2\u01a9\u01ab\5:\36\2\u01aa\u01a8\3\2\2"
-        + "\2\u01aa\u01a9\3\2\2\2\u01ab\67\3\2\2\2\u01ac\u01ad\t\16\2\2\u01ad\u01ae"
-        + "\7W\2\2\u01ae\u01af\5F$\2\u01af9\3\2\2\2\u01b0\u01b1\t\16\2\2\u01b1\u01b2"
-        + "\t\17\2\2\u01b2;\3\2\2\2\u01b3\u01b4\7\7\2\2\u01b4\u01b5\5$\23\2\u01b5"
-        + "\u01b6\7\b\2\2\u01b6=\3\2\2\2\u01b7\u01b8\7\30\2\2\u01b8\u01bd\5\34\17"
-        + "\2\u01b9\u01ba\7\7\2\2\u01ba\u01bb\5$\23\2\u01bb\u01bc\7\b\2\2\u01bc\u01be"
-        + "\3\2\2\2\u01bd\u01b9\3\2\2\2\u01be\u01bf\3\2\2\2\u01bf\u01bd\3\2\2\2\u01bf"
-        + "\u01c0\3\2\2\2\u01c0\u01c8\3\2\2\2\u01c1\u01c5\5\66\34\2\u01c2\u01c4\5"
-        + "\64\33\2\u01c3\u01c2\3\2\2\2\u01c4\u01c7\3\2\2\2\u01c5\u01c3\3\2\2\2\u01c5"
-        + "\u01c6\3\2\2\2\u01c6\u01c9\3\2\2\2\u01c7\u01c5\3\2\2\2\u01c8\u01c1\3\2"
-        + "\2\2\u01c8\u01c9\3\2\2\2\u01c9\u01e1\3\2\2\2\u01ca\u01cb\7\30\2\2\u01cb"
-        + "\u01cc\5\34\17\2\u01cc\u01cd\7\7\2\2\u01cd\u01ce\7\b\2\2\u01ce\u01d7\7"
-        + "\5\2\2\u01cf\u01d4\5$\23\2\u01d0\u01d1\7\r\2\2\u01d1\u01d3\5$\23\2\u01d2"
-        + "\u01d0\3\2\2\2\u01d3\u01d6\3\2\2\2\u01d4\u01d2\3\2\2\2\u01d4\u01d5\3\2"
-        + "\2\2\u01d5\u01d8\3\2\2\2\u01d6\u01d4\3\2\2\2\u01d7\u01cf\3\2\2\2\u01d7"
-        + "\u01d8\3\2\2\2\u01d8\u01d9\3\2\2\2\u01d9\u01dd\7\6\2\2\u01da\u01dc\5\64"
-        + "\33\2\u01db\u01da\3\2\2\2\u01dc\u01df\3\2\2\2\u01dd\u01db\3\2\2\2\u01dd"
-        + "\u01de\3\2\2\2\u01de\u01e1\3\2\2\2\u01df\u01dd\3\2\2\2\u01e0\u01b7\3\2"
-        + "\2\2\u01e0\u01ca\3\2\2\2\u01e1?\3\2\2\2\u01e2\u01e3\7\7\2\2\u01e3\u01e8"
-        + "\5$\23\2\u01e4\u01e5\7\r\2\2\u01e5\u01e7\5$\23\2\u01e6\u01e4\3\2\2\2\u01e7"
-        + "\u01ea\3\2\2\2\u01e8\u01e6\3\2\2\2\u01e8\u01e9\3\2\2\2\u01e9\u01eb\3\2"
-        + "\2\2\u01ea\u01e8\3\2\2\2\u01eb\u01ec\7\b\2\2\u01ec\u01f0\3\2\2\2\u01ed"
-        + "\u01ee\7\7\2\2\u01ee\u01f0\7\b\2\2\u01ef\u01e2\3\2\2\2\u01ef\u01ed\3\2"
-        + "\2\2\u01f0A\3\2\2\2\u01f1\u01f2\7\7\2\2\u01f2\u01f7\5D#\2\u01f3\u01f4"
-        + "\7\r\2\2\u01f4\u01f6\5D#\2\u01f5\u01f3\3\2\2\2\u01f6\u01f9\3\2\2\2\u01f7"
-        + "\u01f5\3\2\2\2\u01f7\u01f8\3\2\2\2\u01f8\u01fa\3\2\2\2\u01f9\u01f7\3\2"
-        + "\2\2\u01fa\u01fb\7\b\2\2\u01fb\u0200\3\2\2\2\u01fc\u01fd\7\7\2\2\u01fd"
-        + "\u01fe\7\66\2\2\u01fe\u0200\7\b\2\2\u01ff\u01f1\3\2\2\2\u01ff\u01fc\3"
-        + "\2\2\2\u0200C\3\2\2\2\u0201\u0202\5$\23\2\u0202\u0203\7\66\2\2\u0203\u0204"
-        + "\5$\23\2\u0204E\3\2\2\2\u0205\u020e\7\t\2\2\u0206\u020b\5H%\2\u0207\u0208"
-        + "\7\r\2\2\u0208\u020a\5H%\2\u0209\u0207\3\2\2\2\u020a\u020d\3\2\2\2\u020b"
-        + "\u0209\3\2\2\2\u020b\u020c\3\2\2\2\u020c\u020f\3\2\2\2\u020d\u020b\3\2"
-        + "\2\2\u020e\u0206\3\2\2\2\u020e\u020f\3\2\2\2\u020f\u0210\3\2\2\2\u0210"
-        + "\u0211\7\n\2\2\u0211G\3\2\2\2\u0212\u0216\5$\23\2\u0213\u0216\5J&\2\u0214"
-        + "\u0216\5N(\2\u0215\u0212\3\2\2\2\u0215\u0213\3\2\2\2\u0215\u0214\3\2\2"
-        + "\2\u0216I\3\2\2\2\u0217\u0225\5L\'\2\u0218\u0221\7\t\2\2\u0219\u021e\5"
-        + "L\'\2\u021a\u021b\7\r\2\2\u021b\u021d\5L\'\2\u021c\u021a\3\2\2\2\u021d"
-        + "\u0220\3\2\2\2\u021e\u021c\3\2\2\2\u021e\u021f\3\2\2\2\u021f\u0222\3\2"
-        + "\2\2\u0220\u021e\3\2\2\2\u0221\u0219\3\2\2\2\u0221\u0222\3\2\2\2\u0222"
-        + "\u0223\3\2\2\2\u0223\u0225\7\n\2\2\u0224\u0217\3\2\2\2\u0224\u0218\3\2"
-        + "\2\2\u0225\u0226\3\2\2\2\u0226\u0229\79\2\2\u0227\u022a\5\20\t\2\u0228"
-        + "\u022a\5$\23\2\u0229\u0227\3\2\2\2\u0229\u0228\3\2\2\2\u022aK\3\2\2\2"
-        + "\u022b\u022d\5\32\16\2\u022c\u022b\3\2\2\2\u022c\u022d\3\2\2\2\u022d\u022e"
-        + "\3\2\2\2\u022e\u022f\7U\2\2\u022fM\3\2\2\2\u0230\u0231\5\32\16\2\u0231"
-        + "\u0232\78\2\2\u0232\u0233\7U\2\2\u0233\u023c\3\2\2\2\u0234\u0235\5\32"
-        + "\16\2\u0235\u0236\78\2\2\u0236\u0237\7\30\2\2\u0237\u023c\3\2\2\2\u0238"
-        + "\u0239\7\34\2\2\u0239\u023a\78\2\2\u023a\u023c\7U\2\2\u023b\u0230\3\2"
-        + "\2\2\u023b\u0234\3\2\2\2\u023b\u0238\3\2\2\2\u023cO\3\2\2\2>SYlow\u0081"
-        + "\u0089\u008e\u0092\u0096\u009b\u00b3\u00b5\u00c3\u00c8\u00cc\u00d2\u00d6"
-        + "\u00de\u00e8\u00f0\u00fa\u00fd\u0102\u0135\u0137\u0145\u014c\u0155\u0161"
-        + "\u016a\u0171\u0178\u017f\u0182\u0188\u018c\u01a1\u01a6\u01aa\u01bf\u01c5"
-        + "\u01c8\u01d4\u01d7\u01dd\u01e0\u01e8\u01ef\u01f7\u01ff\u020b\u020e\u0215"
-        + "\u021e\u0221\u0224\u0229\u022c\u023b";
+    public static final String _serializedATN = "\u0004\u0001U\u023c\u0002\u0000\u0007\u0000\u0002\u0001\u0007\u0001\u0002"
+        + "\u0002\u0007\u0002\u0002\u0003\u0007\u0003\u0002\u0004\u0007\u0004\u0002"
+        + "\u0005\u0007\u0005\u0002\u0006\u0007\u0006\u0002\u0007\u0007\u0007\u0002"
+        + "\b\u0007\b\u0002\t\u0007\t\u0002\n\u0007\n\u0002\u000b\u0007\u000b\u0002"
+        + "\f\u0007\f\u0002\r\u0007\r\u0002\u000e\u0007\u000e\u0002\u000f\u0007\u000f"
+        + "\u0002\u0010\u0007\u0010\u0002\u0011\u0007\u0011\u0002\u0012\u0007\u0012"
+        + "\u0002\u0013\u0007\u0013\u0002\u0014\u0007\u0014\u0002\u0015\u0007\u0015"
+        + "\u0002\u0016\u0007\u0016\u0002\u0017\u0007\u0017\u0002\u0018\u0007\u0018"
+        + "\u0002\u0019\u0007\u0019\u0002\u001a\u0007\u001a\u0002\u001b\u0007\u001b"
+        + "\u0002\u001c\u0007\u001c\u0002\u001d\u0007\u001d\u0002\u001e\u0007\u001e"
+        + "\u0002\u001f\u0007\u001f\u0002 \u0007 \u0002!\u0007!\u0002\"\u0007\"\u0002"
+        + "#\u0007#\u0002$\u0007$\u0002%\u0007%\u0002&\u0007&\u0001\u0000\u0005\u0000"
+        + "P\b\u0000\n\u0000\f\u0000S\t\u0000\u0001\u0000\u0005\u0000V\b\u0000\n"
+        + "\u0000\f\u0000Y\t\u0000\u0001\u0000\u0001\u0000\u0001\u0001\u0001\u0001"
+        + "\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0002\u0001\u0002\u0001\u0002"
+        + "\u0001\u0002\u0001\u0002\u0001\u0002\u0001\u0002\u0005\u0002i\b\u0002"
+        + "\n\u0002\f\u0002l\t\u0002\u0003\u0002n\b\u0002\u0001\u0002\u0001\u0002"
+        + "\u0001\u0003\u0001\u0003\u0001\u0003\u0001\u0003\u0003\u0003v\b\u0003"
+        + "\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004"
+        + "\u0001\u0004\u0001\u0004\u0003\u0004\u0080\b\u0004\u0001\u0004\u0001\u0004"
+        + "\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0003\u0004\u0088\b\u0004"
+        + "\u0001\u0004\u0001\u0004\u0001\u0004\u0003\u0004\u008d\b\u0004\u0001\u0004"
+        + "\u0001\u0004\u0003\u0004\u0091\b\u0004\u0001\u0004\u0001\u0004\u0003\u0004"
+        + "\u0095\b\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0003\u0004\u009a\b"
+        + "\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001"
+        + "\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001"
+        + "\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001\u0004\u0001"
+        + "\u0004\u0001\u0004\u0001\u0004\u0004\u0004\u00b0\b\u0004\u000b\u0004\f"
+        + "\u0004\u00b1\u0003\u0004\u00b4\b\u0004\u0001\u0005\u0001\u0005\u0001\u0005"
+        + "\u0001\u0005\u0001\u0005\u0001\u0005\u0001\u0005\u0001\u0005\u0001\u0005"
+        + "\u0001\u0005\u0001\u0005\u0001\u0005\u0003\u0005\u00c2\b\u0005\u0001\u0005"
+        + "\u0001\u0005\u0001\u0005\u0003\u0005\u00c7\b\u0005\u0001\u0006\u0001\u0006"
+        + "\u0003\u0006\u00cb\b\u0006\u0001\u0007\u0001\u0007\u0005\u0007\u00cf\b"
+        + "\u0007\n\u0007\f\u0007\u00d2\t\u0007\u0001\u0007\u0003\u0007\u00d5\b\u0007"
+        + "\u0001\u0007\u0001\u0007\u0001\b\u0001\b\u0001\t\u0001\t\u0003\t\u00dd"
+        + "\b\t\u0001\n\u0001\n\u0001\u000b\u0001\u000b\u0001\u000b\u0001\u000b\u0005"
+        + "\u000b\u00e5\b\u000b\n\u000b\f\u000b\u00e8\t\u000b\u0001\f\u0001\f\u0001"
+        + "\f\u0005\f\u00ed\b\f\n\f\f\f\u00f0\t\f\u0001\r\u0001\r\u0001\r\u0001\r"
+        + "\u0001\r\u0005\r\u00f7\b\r\n\r\f\r\u00fa\t\r\u0003\r\u00fc\b\r\u0001\u000e"
+        + "\u0001\u000e\u0001\u000e\u0003\u000e\u0101\b\u000e\u0001\u000f\u0001\u000f"
+        + "\u0001\u000f\u0001\u000f\u0001\u000f\u0001\u000f\u0001\u000f\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010"
+        + "\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0001\u0010\u0005\u0010"
+        + "\u0134\b\u0010\n\u0010\f\u0010\u0137\t\u0010\u0001\u0011\u0001\u0011\u0001"
+        + "\u0011\u0001\u0011\u0001\u0011\u0001\u0011\u0001\u0011\u0001\u0011\u0001"
+        + "\u0011\u0001\u0011\u0001\u0011\u0003\u0011\u0144\b\u0011\u0001\u0012\u0001"
+        + "\u0012\u0001\u0012\u0001\u0012\u0001\u0012\u0003\u0012\u014b\b\u0012\u0001"
+        + "\u0013\u0001\u0013\u0001\u0013\u0001\u0013\u0001\u0013\u0001\u0013\u0001"
+        + "\u0013\u0003\u0013\u0154\b\u0013\u0001\u0014\u0001\u0014\u0001\u0014\u0001"
+        + "\u0014\u0001\u0014\u0001\u0014\u0001\u0014\u0001\u0014\u0001\u0014\u0001"
+        + "\u0014\u0003\u0014\u0160\b\u0014\u0001\u0015\u0001\u0015\u0001\u0016\u0001"
+        + "\u0016\u0001\u0016\u0004\u0016\u0167\b\u0016\u000b\u0016\f\u0016\u0168"
+        + "\u0001\u0016\u0001\u0016\u0001\u0016\u0004\u0016\u016e\b\u0016\u000b\u0016"
+        + "\f\u0016\u016f\u0001\u0016\u0001\u0016\u0001\u0016\u0005\u0016\u0175\b"
+        + "\u0016\n\u0016\f\u0016\u0178\t\u0016\u0001\u0016\u0001\u0016\u0005\u0016"
+        + "\u017c\b\u0016\n\u0016\f\u0016\u017f\t\u0016\u0003\u0016\u0181\b\u0016"
+        + "\u0001\u0017\u0001\u0017\u0005\u0017\u0185\b\u0017\n\u0017\f\u0017\u0188"
+        + "\t\u0017\u0001\u0017\u0003\u0017\u018b\b\u0017\u0001\u0018\u0001\u0018"
+        + "\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018"
+        + "\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018"
+        + "\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0001\u0018\u0003\u0018"
+        + "\u01a0\b\u0018\u0001\u0019\u0001\u0019\u0001\u0019\u0003\u0019\u01a5\b"
+        + "\u0019\u0001\u001a\u0001\u001a\u0003\u001a\u01a9\b\u001a\u0001\u001b\u0001"
+        + "\u001b\u0001\u001b\u0001\u001b\u0001\u001c\u0001\u001c\u0001\u001c\u0001"
+        + "\u001d\u0001\u001d\u0001\u001d\u0001\u001d\u0001\u001e\u0001\u001e\u0001"
+        + "\u001e\u0001\u001e\u0001\u001e\u0001\u001e\u0004\u001e\u01bc\b\u001e\u000b"
+        + "\u001e\f\u001e\u01bd\u0001\u001e\u0001\u001e\u0005\u001e\u01c2\b\u001e"
+        + "\n\u001e\f\u001e\u01c5\t\u001e\u0003\u001e\u01c7\b\u001e\u0001\u001e\u0001"
+        + "\u001e\u0001\u001e\u0001\u001e\u0001\u001e\u0001\u001e\u0001\u001e\u0001"
+        + "\u001e\u0005\u001e\u01d1\b\u001e\n\u001e\f\u001e\u01d4\t\u001e\u0003\u001e"
+        + "\u01d6\b\u001e\u0001\u001e\u0001\u001e\u0005\u001e\u01da\b\u001e\n\u001e"
+        + "\f\u001e\u01dd\t\u001e\u0003\u001e\u01df\b\u001e\u0001\u001f\u0001\u001f"
+        + "\u0001\u001f\u0001\u001f\u0005\u001f\u01e5\b\u001f\n\u001f\f\u001f\u01e8"
+        + "\t\u001f\u0001\u001f\u0001\u001f\u0001\u001f\u0001\u001f\u0003\u001f\u01ee"
+        + "\b\u001f\u0001 \u0001 \u0001 \u0001 \u0005 \u01f4\b \n \f \u01f7\t \u0001"
+        + " \u0001 \u0001 \u0001 \u0001 \u0003 \u01fe\b \u0001!\u0001!\u0001!\u0001"
+        + "!\u0001\"\u0001\"\u0001\"\u0001\"\u0005\"\u0208\b\"\n\"\f\"\u020b\t\""
+        + "\u0003\"\u020d\b\"\u0001\"\u0001\"\u0001#\u0001#\u0001#\u0003#\u0214\b"
+        + "#\u0001$\u0001$\u0001$\u0001$\u0001$\u0005$\u021b\b$\n$\f$\u021e\t$\u0003"
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+        + "\u0000\u0158\u0159\u0003$\u0012\u0000\u0159\u0160\u0001\u0000\u0000\u0000"
+        + "\u015a\u015b\u0005\u0007\u0000\u0000\u015b\u015c\u0003,\u0016\u0000\u015c"
+        + "\u015d\u0005\b\u0000\u0000\u015d\u015e\u0003&\u0013\u0000\u015e\u0160"
+        + "\u0001\u0000\u0000\u0000\u015f\u0155\u0001\u0000\u0000\u0000\u015f\u015a"
+        + "\u0001\u0000\u0000\u0000\u0160)\u0001\u0000\u0000\u0000\u0161\u0162\u0007"
+        + "\n\u0000\u0000\u0162+\u0001\u0000\u0000\u0000\u0163\u0166\u0005R\u0000"
+        + "\u0000\u0164\u0165\u0005\u0005\u0000\u0000\u0165\u0167\u0005\u0006\u0000"
+        + "\u0000\u0166\u0164\u0001\u0000\u0000\u0000\u0167\u0168\u0001\u0000\u0000"
+        + "\u0000\u0168\u0166\u0001\u0000\u0000\u0000\u0168\u0169\u0001\u0000\u0000"
+        + "\u0000\u0169\u0181\u0001\u0000\u0000\u0000\u016a\u016d\u0005Q\u0000\u0000"
+        + "\u016b\u016c\u0005\u0005\u0000\u0000\u016c\u016e\u0005\u0006\u0000\u0000"
+        + "\u016d\u016b\u0001\u0000\u0000\u0000\u016e\u016f\u0001\u0000\u0000\u0000"
+        + "\u016f\u016d\u0001\u0000\u0000\u0000\u016f\u0170\u0001\u0000\u0000\u0000"
+        + "\u0170\u0181\u0001\u0000\u0000\u0000\u0171\u0176\u0005S\u0000\u0000\u0172"
+        + "\u0173\u0005\t\u0000\u0000\u0173\u0175\u0005U\u0000\u0000\u0174\u0172"
+        + "\u0001\u0000\u0000\u0000\u0175\u0178\u0001\u0000\u0000\u0000\u0176\u0174"
+        + "\u0001\u0000\u0000\u0000\u0176\u0177\u0001\u0000\u0000\u0000\u0177\u017d"
+        + "\u0001\u0000\u0000\u0000\u0178\u0176\u0001\u0000\u0000\u0000\u0179\u017a"
+        + "\u0005\u0005\u0000\u0000\u017a\u017c\u0005\u0006\u0000\u0000\u017b\u0179"
+        + "\u0001\u0000\u0000\u0000\u017c\u017f\u0001\u0000\u0000\u0000\u017d\u017b"
+        + "\u0001\u0000\u0000\u0000\u017d\u017e\u0001\u0000\u0000\u0000\u017e\u0181"
+        + "\u0001\u0000\u0000\u0000\u017f\u017d\u0001\u0000\u0000\u0000\u0180\u0163"
+        + "\u0001\u0000\u0000\u0000\u0180\u016a\u0001\u0000\u0000\u0000\u0180\u0171"
+        + "\u0001\u0000\u0000\u0000\u0181-\u0001\u0000\u0000\u0000\u0182\u0186\u0003"
+        + "0\u0018\u0000\u0183\u0185\u00032\u0019\u0000\u0184\u0183\u0001\u0000\u0000"
+        + "\u0000\u0185\u0188\u0001\u0000\u0000\u0000\u0186\u0184\u0001\u0000\u0000"
+        + "\u0000\u0186\u0187\u0001\u0000\u0000\u0000\u0187\u018b\u0001\u0000\u0000"
+        + "\u0000\u0188\u0186\u0001\u0000\u0000\u0000\u0189\u018b\u0003<\u001e\u0000"
+        + "\u018a\u0182\u0001\u0000\u0000\u0000\u018a\u0189\u0001\u0000\u0000\u0000"
+        + "\u018b/\u0001\u0000\u0000\u0000\u018c\u018d\u0005\u0007\u0000\u0000\u018d"
+        + "\u018e\u0003\"\u0011\u0000\u018e\u018f\u0005\b\u0000\u0000\u018f\u01a0"
+        + "\u0001\u0000\u0000\u0000\u0190\u01a0\u0007\u000b\u0000\u0000\u0191\u01a0"
+        + "\u0005N\u0000\u0000\u0192\u01a0\u0005O\u0000\u0000\u0193\u01a0\u0005P"
+        + "\u0000\u0000\u0194\u01a0\u0005L\u0000\u0000\u0195\u01a0\u0005M\u0000\u0000"
+        + "\u0196\u01a0\u0003>\u001f\u0000\u0197\u01a0\u0003@ \u0000\u0198\u01a0"
+        + "\u0005S\u0000\u0000\u0199\u019a\u0005S\u0000\u0000\u019a\u01a0\u0003D"
+        + "\"\u0000\u019b\u019c\u0005\u0016\u0000\u0000\u019c\u019d\u0003\u001a\r"
+        + "\u0000\u019d\u019e\u0003D\"\u0000\u019e\u01a0\u0001\u0000\u0000\u0000"
+        + "\u019f\u018c\u0001\u0000\u0000\u0000\u019f\u0190\u0001\u0000\u0000\u0000"
+        + "\u019f\u0191\u0001\u0000\u0000\u0000\u019f\u0192\u0001\u0000\u0000\u0000"
+        + "\u019f\u0193\u0001\u0000\u0000\u0000\u019f\u0194\u0001\u0000\u0000\u0000"
+        + "\u019f\u0195\u0001\u0000\u0000\u0000\u019f\u0196\u0001\u0000\u0000\u0000"
+        + "\u019f\u0197\u0001\u0000\u0000\u0000\u019f\u0198\u0001\u0000\u0000\u0000"
+        + "\u019f\u0199\u0001\u0000\u0000\u0000\u019f\u019b\u0001\u0000\u0000\u0000"
+        + "\u01a01\u0001\u0000\u0000\u0000\u01a1\u01a5\u00036\u001b\u0000\u01a2\u01a5"
+        + "\u00038\u001c\u0000\u01a3\u01a5\u0003:\u001d\u0000\u01a4\u01a1\u0001\u0000"
+        + "\u0000\u0000\u01a4\u01a2\u0001\u0000\u0000\u0000\u01a4\u01a3\u0001\u0000"
+        + "\u0000\u0000\u01a53\u0001\u0000\u0000\u0000\u01a6\u01a9\u00036\u001b\u0000"
+        + "\u01a7\u01a9\u00038\u001c\u0000\u01a8\u01a6\u0001\u0000\u0000\u0000\u01a8"
+        + "\u01a7\u0001\u0000\u0000\u0000\u01a95\u0001\u0000\u0000\u0000\u01aa\u01ab"
+        + "\u0007\f\u0000\u0000\u01ab\u01ac\u0005U\u0000\u0000\u01ac\u01ad\u0003"
+        + "D\"\u0000\u01ad7\u0001\u0000\u0000\u0000\u01ae\u01af\u0007\f\u0000\u0000"
+        + "\u01af\u01b0\u0007\r\u0000\u0000\u01b09\u0001\u0000\u0000\u0000\u01b1"
+        + "\u01b2\u0005\u0005\u0000\u0000\u01b2\u01b3\u0003\"\u0011\u0000\u01b3\u01b4"
+        + "\u0005\u0006\u0000\u0000\u01b4;\u0001\u0000\u0000\u0000\u01b5\u01b6\u0005"
+        + "\u0016\u0000\u0000\u01b6\u01bb\u0003\u001a\r\u0000\u01b7\u01b8\u0005\u0005"
+        + "\u0000\u0000\u01b8\u01b9\u0003\"\u0011\u0000\u01b9\u01ba\u0005\u0006\u0000"
+        + "\u0000\u01ba\u01bc\u0001\u0000\u0000\u0000\u01bb\u01b7\u0001\u0000\u0000"
+        + "\u0000\u01bc\u01bd\u0001\u0000\u0000\u0000\u01bd\u01bb\u0001\u0000\u0000"
+        + "\u0000\u01bd\u01be\u0001\u0000\u0000\u0000\u01be\u01c6\u0001\u0000\u0000"
+        + "\u0000\u01bf\u01c3\u00034\u001a\u0000\u01c0\u01c2\u00032\u0019\u0000\u01c1"
+        + "\u01c0\u0001\u0000\u0000\u0000\u01c2\u01c5\u0001\u0000\u0000\u0000\u01c3"
+        + "\u01c1\u0001\u0000\u0000\u0000\u01c3\u01c4\u0001\u0000\u0000\u0000\u01c4"
+        + "\u01c7\u0001\u0000\u0000\u0000\u01c5\u01c3\u0001\u0000\u0000\u0000\u01c6"
+        + "\u01bf\u0001\u0000\u0000\u0000\u01c6\u01c7\u0001\u0000\u0000\u0000\u01c7"
+        + "\u01df\u0001\u0000\u0000\u0000\u01c8\u01c9\u0005\u0016\u0000\u0000\u01c9"
+        + "\u01ca\u0003\u001a\r\u0000\u01ca\u01cb\u0005\u0005\u0000\u0000\u01cb\u01cc"
+        + "\u0005\u0006\u0000\u0000\u01cc\u01d5\u0005\u0003\u0000\u0000\u01cd\u01d2"
+        + "\u0003\"\u0011\u0000\u01ce\u01cf\u0005\u000b\u0000\u0000\u01cf\u01d1\u0003"
+        + "\"\u0011\u0000\u01d0\u01ce\u0001\u0000\u0000\u0000\u01d1\u01d4\u0001\u0000"
+        + "\u0000\u0000\u01d2\u01d0\u0001\u0000\u0000\u0000\u01d2\u01d3\u0001\u0000"
+        + "\u0000\u0000\u01d3\u01d6\u0001\u0000\u0000\u0000\u01d4\u01d2\u0001\u0000"
+        + "\u0000\u0000\u01d5\u01cd\u0001\u0000\u0000\u0000\u01d5\u01d6\u0001\u0000"
+        + "\u0000\u0000\u01d6\u01d7\u0001\u0000\u0000\u0000\u01d7\u01db\u0005\u0004"
+        + "\u0000\u0000\u01d8\u01da\u00032\u0019\u0000\u01d9\u01d8\u0001\u0000\u0000"
+        + "\u0000\u01da\u01dd\u0001\u0000\u0000\u0000\u01db\u01d9\u0001\u0000\u0000"
+        + "\u0000\u01db\u01dc\u0001\u0000\u0000\u0000\u01dc\u01df\u0001\u0000\u0000"
+        + "\u0000\u01dd\u01db\u0001\u0000\u0000\u0000\u01de\u01b5\u0001\u0000\u0000"
+        + "\u0000\u01de\u01c8\u0001\u0000\u0000\u0000\u01df=\u0001\u0000\u0000\u0000"
+        + "\u01e0\u01e1\u0005\u0005\u0000\u0000\u01e1\u01e6\u0003\"\u0011\u0000\u01e2"
+        + "\u01e3\u0005\u000b\u0000\u0000\u01e3\u01e5\u0003\"\u0011\u0000\u01e4\u01e2"
+        + "\u0001\u0000\u0000\u0000\u01e5\u01e8\u0001\u0000\u0000\u0000\u01e6\u01e4"
+        + "\u0001\u0000\u0000\u0000\u01e6\u01e7\u0001\u0000\u0000\u0000\u01e7\u01e9"
+        + "\u0001\u0000\u0000\u0000\u01e8\u01e6\u0001\u0000\u0000\u0000\u01e9\u01ea"
+        + "\u0005\u0006\u0000\u0000\u01ea\u01ee\u0001\u0000\u0000\u0000\u01eb\u01ec"
+        + "\u0005\u0005\u0000\u0000\u01ec\u01ee\u0005\u0006\u0000\u0000\u01ed\u01e0"
+        + "\u0001\u0000\u0000\u0000\u01ed\u01eb\u0001\u0000\u0000\u0000\u01ee?\u0001"
+        + "\u0000\u0000\u0000\u01ef\u01f0\u0005\u0005\u0000\u0000\u01f0\u01f5\u0003"
+        + "B!\u0000\u01f1\u01f2\u0005\u000b\u0000\u0000\u01f2\u01f4\u0003B!\u0000"
+        + "\u01f3\u01f1\u0001\u0000\u0000\u0000\u01f4\u01f7\u0001\u0000\u0000\u0000"
+        + "\u01f5\u01f3\u0001\u0000\u0000\u0000\u01f5\u01f6\u0001\u0000\u0000\u0000"
+        + "\u01f6\u01f8\u0001\u0000\u0000\u0000\u01f7\u01f5\u0001\u0000\u0000\u0000"
+        + "\u01f8\u01f9\u0005\u0006\u0000\u0000\u01f9\u01fe\u0001\u0000\u0000\u0000"
+        + "\u01fa\u01fb\u0005\u0005\u0000\u0000\u01fb\u01fc\u00054\u0000\u0000\u01fc"
+        + "\u01fe\u0005\u0006\u0000\u0000\u01fd\u01ef\u0001\u0000\u0000\u0000\u01fd"
+        + "\u01fa\u0001\u0000\u0000\u0000\u01feA\u0001\u0000\u0000\u0000\u01ff\u0200"
+        + "\u0003\"\u0011\u0000\u0200\u0201\u00054\u0000\u0000\u0201\u0202\u0003"
+        + "\"\u0011\u0000\u0202C\u0001\u0000\u0000\u0000\u0203\u020c\u0005\u0007"
+        + "\u0000\u0000\u0204\u0209\u0003F#\u0000\u0205\u0206\u0005\u000b\u0000\u0000"
+        + "\u0206\u0208\u0003F#\u0000\u0207\u0205\u0001\u0000\u0000\u0000\u0208\u020b"
+        + "\u0001\u0000\u0000\u0000\u0209\u0207\u0001\u0000\u0000\u0000\u0209\u020a"
+        + "\u0001\u0000\u0000\u0000\u020a\u020d\u0001\u0000\u0000\u0000\u020b\u0209"
+        + "\u0001\u0000\u0000\u0000\u020c\u0204\u0001\u0000\u0000\u0000\u020c\u020d"
+        + "\u0001\u0000\u0000\u0000\u020d\u020e\u0001\u0000\u0000\u0000\u020e\u020f"
+        + "\u0005\b\u0000\u0000\u020fE\u0001\u0000\u0000\u0000\u0210\u0214\u0003"
+        + "\"\u0011\u0000\u0211\u0214\u0003H$\u0000\u0212\u0214\u0003L&\u0000\u0213"
+        + "\u0210\u0001\u0000\u0000\u0000\u0213\u0211\u0001\u0000\u0000\u0000\u0213"
+        + "\u0212\u0001\u0000\u0000\u0000\u0214G\u0001\u0000\u0000\u0000\u0215\u0223"
+        + "\u0003J%\u0000\u0216\u021f\u0005\u0007\u0000\u0000\u0217\u021c\u0003J"
+        + "%\u0000\u0218\u0219\u0005\u000b\u0000\u0000\u0219\u021b\u0003J%\u0000"
+        + "\u021a\u0218\u0001\u0000\u0000\u0000\u021b\u021e\u0001\u0000\u0000\u0000"
+        + "\u021c\u021a\u0001\u0000\u0000\u0000\u021c\u021d\u0001\u0000\u0000\u0000"
+        + "\u021d\u0220\u0001\u0000\u0000\u0000\u021e\u021c\u0001\u0000\u0000\u0000"
+        + "\u021f\u0217\u0001\u0000\u0000\u0000\u021f\u0220\u0001\u0000\u0000\u0000"
+        + "\u0220\u0221\u0001\u0000\u0000\u0000\u0221\u0223\u0005\b\u0000\u0000\u0222"
+        + "\u0215\u0001\u0000\u0000\u0000\u0222\u0216\u0001\u0000\u0000\u0000\u0223"
+        + "\u0224\u0001\u0000\u0000\u0000\u0224\u0227\u00057\u0000\u0000\u0225\u0228"
+        + "\u0003\u000e\u0007\u0000\u0226\u0228\u0003\"\u0011\u0000\u0227\u0225\u0001"
+        + "\u0000\u0000\u0000\u0227\u0226\u0001\u0000\u0000\u0000\u0228I\u0001\u0000"
+        + "\u0000\u0000\u0229\u022b\u0003\u0018\f\u0000\u022a\u0229\u0001\u0000\u0000"
+        + "\u0000\u022a\u022b\u0001\u0000\u0000\u0000\u022b\u022c\u0001\u0000\u0000"
+        + "\u0000\u022c\u022d\u0005S\u0000\u0000\u022dK\u0001\u0000\u0000\u0000\u022e"
+        + "\u022f\u0003\u0018\f\u0000\u022f\u0230\u00056\u0000\u0000\u0230\u0231"
+        + "\u0005S\u0000\u0000\u0231\u023a\u0001\u0000\u0000\u0000\u0232\u0233\u0003"
+        + "\u0018\f\u0000\u0233\u0234\u00056\u0000\u0000\u0234\u0235\u0005\u0016"
+        + "\u0000\u0000\u0235\u023a\u0001\u0000\u0000\u0000\u0236\u0237\u0005\u001a"
+        + "\u0000\u0000\u0237\u0238\u00056\u0000\u0000\u0238\u023a\u0005S\u0000\u0000"
+        + "\u0239\u022e\u0001\u0000\u0000\u0000\u0239\u0232\u0001\u0000\u0000\u0000"
+        + "\u0239\u0236\u0001\u0000\u0000\u0000\u023aM\u0001\u0000\u0000\u0000<Q"
+        + "Wjmu\u007f\u0087\u008c\u0090\u0094\u0099\u00b1\u00b3\u00c1\u00c6\u00ca"
+        + "\u00d0\u00d4\u00dc\u00e6\u00ee\u00f8\u00fb\u0100\u0133\u0135\u0143\u014a"
+        + "\u0153\u015f\u0168\u016f\u0176\u017d\u0180\u0186\u018a\u019f\u01a4\u01a8"
+        + "\u01bd\u01c3\u01c6\u01d2\u01d5\u01db\u01de\u01e6\u01ed\u01f5\u01fd\u0209"
+        + "\u020c\u0213\u021c\u021f\u0222\u0227\u022a\u0239";
     public static final ATN _ATN = new ATNDeserializer().deserialize(_serializedATN.toCharArray());
     static {
         _decisionToDFA = new DFA[_ATN.getNumberOfDecisions()];
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParserBaseVisitor.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParserBaseVisitor.java
index f347d90f2cc33..41529bf667b0d 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParserBaseVisitor.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/PainlessParserBaseVisitor.java
@@ -43,6 +43,7 @@
  * @param <T> The return type of the visit operation. Use {@link Void} for
  * operations with no return type.
  */
+@SuppressWarnings("CheckReturnValue")
 class PainlessParserBaseVisitor<T> extends AbstractParseTreeVisitor<T> implements PainlessParserVisitor<T> {
     /**
      * {@inheritDoc}
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/ParserErrorStrategy.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/ParserErrorStrategy.java
index 7ddf9cd54fe83..6928b28a746f6 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/ParserErrorStrategy.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/ParserErrorStrategy.java
@@ -38,6 +38,7 @@
 import org.antlr.v4.runtime.Parser;
 import org.antlr.v4.runtime.RecognitionException;
 import org.antlr.v4.runtime.Token;
+
 import org.opensearch.painless.Location;
 
 /**
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/Walker.java b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/Walker.java
index 719a69a9977e7..927c75d8ee9d2 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/Walker.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/antlr/Walker.java
@@ -41,6 +41,7 @@
 import org.antlr.v4.runtime.Recognizer;
 import org.antlr.v4.runtime.atn.PredictionMode;
 import org.antlr.v4.runtime.tree.TerminalNode;
+
 import org.opensearch.painless.CompilerSettings;
 import org.opensearch.painless.Location;
 import org.opensearch.painless.Operation;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/api/Json.java b/modules/lang-painless/src/main/java/org/opensearch/painless/api/Json.java
index 89f756ef8b76a..e3dd1b50736fa 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/api/Json.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/api/Json.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.painless.api;
 
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.OutputStream;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/api/LimitedCharSequence.java b/modules/lang-painless/src/main/java/org/opensearch/painless/api/LimitedCharSequence.java
index 8084420295280..c8a28158ad8db 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/api/LimitedCharSequence.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/api/LimitedCharSequence.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.painless.api;
 
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
 import org.opensearch.painless.CompilerSettings;
 
 import java.util.regex.Pattern;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessClass.java b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessClass.java
index efa2d51524557..fdf7df94252b6 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessClass.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessClass.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.painless.lookup;
 
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.lang.invoke.MethodHandle;
 import java.util.Map;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookup.java b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookup.java
index 1249a9cffecb2..9a3b8bf9e2eee 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookup.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookup.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.painless.lookup;
 
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.lang.invoke.MethodHandle;
 import java.util.Map;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookupBuilder.java b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookupBuilder.java
index ff3fbc640e990..54484e6685996 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookupBuilder.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/lookup/PainlessLookupBuilder.java
@@ -2168,9 +2168,10 @@ private void generateBridgeMethod(PainlessClassBuilder painlessClassBuilder, Pai
                 bridgeMethodWriter.loadArg(0);
             }
 
-            for (int typeParameterCount = 0; typeParameterCount < javaMethod.getParameterTypes().length; ++typeParameterCount) {
+            final Class<?>[] typeParameters = javaMethod.getParameterTypes();
+            for (int typeParameterCount = 0; typeParameterCount < typeParameters.length; ++typeParameterCount) {
                 bridgeMethodWriter.loadArg(typeParameterCount + bridgeTypeParameterOffset);
-                Class<?> typeParameter = javaMethod.getParameterTypes()[typeParameterCount];
+                Class<?> typeParameter = typeParameters[typeParameterCount];
 
                 if (typeParameter == Byte.class) bridgeMethodWriter.invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_BYTE_IMPLICIT);
                 else if (typeParameter == Short.class) bridgeMethodWriter.invokeStatic(DEF_UTIL_TYPE, DEF_TO_B_SHORT_IMPLICIT);
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/DefaultConstantFoldingOptimizationPhase.java b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/DefaultConstantFoldingOptimizationPhase.java
index 8b55e70e8ea7c..06607b639e07c 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/DefaultConstantFoldingOptimizationPhase.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/DefaultConstantFoldingOptimizationPhase.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.painless.AnalyzerCaster;
 import org.opensearch.painless.Operation;
-import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BinaryImplNode;
+import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BooleanNode;
 import org.opensearch.painless.ir.CastNode;
 import org.opensearch.painless.ir.ComparisonNode;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeBaseVisitor.java b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeBaseVisitor.java
index 0b947decd7dad..deff3201a2fd5 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeBaseVisitor.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeBaseVisitor.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.painless.phase;
 
-import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BinaryImplNode;
+import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BlockNode;
 import org.opensearch.painless.ir.BooleanNode;
 import org.opensearch.painless.ir.BreakNode;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeVisitor.java b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeVisitor.java
index babb9b14bcfb1..17bd1889a11bc 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeVisitor.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/phase/IRTreeVisitor.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.painless.phase;
 
-import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BinaryImplNode;
+import org.opensearch.painless.ir.BinaryMathNode;
 import org.opensearch.painless.ir.BlockNode;
 import org.opensearch.painless.ir.BooleanNode;
 import org.opensearch.painless.ir.BreakNode;
diff --git a/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.score.txt b/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.score.txt
index cca7e07a95388..b9268421c7ef3 100644
--- a/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.score.txt
+++ b/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.score.txt
@@ -23,6 +23,9 @@ class org.opensearch.script.ScoreScript @no_import {
 }
 
 static_import {
+    int termFreq(org.opensearch.script.ScoreScript, String, String) bound_to org.opensearch.script.ScoreScriptUtils$TermFreq
+    long totalTermFreq(org.opensearch.script.ScoreScript, String, String) bound_to org.opensearch.script.ScoreScriptUtils$TotalTermFreq
+    long sumTotalTermFreq(org.opensearch.script.ScoreScript, String) bound_to org.opensearch.script.ScoreScriptUtils$SumTotalTermFreq
     double saturation(double, double) from_class org.opensearch.script.ScoreScriptUtils
     double sigmoid(double, double, double) from_class org.opensearch.script.ScoreScriptUtils
     double randomScore(org.opensearch.script.ScoreScript, int, String) bound_to org.opensearch.script.ScoreScriptUtils$RandomScoreField
diff --git a/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.txt b/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.txt
index debccf8ed4b9b..8009280857a63 100644
--- a/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.txt
+++ b/modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.txt
@@ -74,6 +74,11 @@ class org.opensearch.index.fielddata.ScriptDocValues$Longs {
   long getValue()
 }
 
+class org.opensearch.index.fielddata.ScriptDocValues$UnsignedLongs {
+  BigInteger get(int)
+  BigInteger getValue()
+}
+
 class org.opensearch.script.JodaCompatibleZonedDateTime {
   ##### ZonedDateTime methods
   int getDayOfMonth()
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/ArrayTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/ArrayTests.java
index 7563ab87fd5e6..0b83a4c558ef6 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/ArrayTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/ArrayTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.painless;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.bootstrap.JavaVersion;
 import org.hamcrest.Matcher;
 
 import java.lang.invoke.MethodHandle;
@@ -55,11 +54,7 @@ protected String valueCtorCall(String valueType, int size) {
 
     @Override
     protected Matcher<String> outOfBoundsExceptionMessageMatcher(int index, int size) {
-        if (JavaVersion.current().compareTo(JavaVersion.parse("11")) < 0) {
-            return equalTo(Integer.toString(index));
-        } else {
-            return equalTo("Index " + Integer.toString(index) + " out of bounds for length " + Integer.toString(size));
-        }
+        return equalTo("Index " + Integer.toString(index) + " out of bounds for length " + Integer.toString(size));
     }
 
     public void testArrayLengthHelper() throws Throwable {
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/AugmentationTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/AugmentationTests.java
index 98b0cad9960f8..d1b4f90a0f309 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/AugmentationTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/AugmentationTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.painless.spi.WhitelistLoader;
 import org.opensearch.script.ScriptContext;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.util.ArrayList;
 import java.util.Arrays;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/BaseClassTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/BaseClassTests.java
index 6892974b6ca7d..599e4047396be 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/BaseClassTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/BaseClassTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.script.ScriptContext;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.util.Collections;
 import java.util.HashMap;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/BasicStatementTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/BasicStatementTests.java
index 403bd12147cfe..fddf069f85c0c 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/BasicStatementTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/BasicStatementTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.script.ScriptContext;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/BindingsTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/BindingsTests.java
index e5113d93677ab..895ff42b9a527 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/BindingsTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/BindingsTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.painless.spi.WhitelistInstanceBinding;
 import org.opensearch.painless.spi.WhitelistLoader;
 import org.opensearch.script.ScriptContext;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/DebugTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/DebugTests.java
index 285de018f1db2..abd6bd91b917e 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/DebugTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/DebugTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.painless.lookup.PainlessLookup;
 import org.opensearch.painless.lookup.PainlessLookupBuilder;
 import org.opensearch.painless.spi.Whitelist;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/DefBootstrapTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/DefBootstrapTests.java
index 9134d7a3c062b..d063a3fd5c0a6 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/DefBootstrapTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/DefBootstrapTests.java
@@ -157,21 +157,13 @@ public void testMegamorphic() throws Throwable {
         map.put("a", "b");
         assertEquals(2, (int) handle.invokeExact((Object) map));
 
-        final IllegalArgumentException iae = expectThrows(
-            IllegalArgumentException.class,
-            () -> { Integer.toString((int) handle.invokeExact(new Object())); }
-        );
+        final IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () -> {
+            Integer.toString((int) handle.invokeExact(new Object()));
+        });
         assertEquals("dynamic method [java.lang.Object, size/0] not found", iae.getMessage());
-        assertTrue(
-            "Does not fail inside ClassValue.computeValue()",
-            Arrays.stream(iae.getStackTrace())
-                .anyMatch(
-                    e -> {
-                        return e.getMethodName().equals("computeValue")
-                            && e.getClassName().startsWith("org.opensearch.painless.DefBootstrap$PIC$");
-                    }
-                )
-        );
+        assertTrue("Does not fail inside ClassValue.computeValue()", Arrays.stream(iae.getStackTrace()).anyMatch(e -> {
+            return e.getMethodName().equals("computeValue") && e.getClassName().startsWith("org.opensearch.painless.DefBootstrap$PIC$");
+        }));
     }
 
     // test operators with null guards
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/FactoryTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/FactoryTests.java
index 7ee0bd6fc096d..2c2c9b8a7c6d8 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/FactoryTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/FactoryTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.ScriptException;
 import org.opensearch.script.ScriptFactory;
 import org.opensearch.script.TemplateScript;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.util.Arrays;
 import java.util.Collections;
@@ -360,6 +360,14 @@ public void testVoidReturn() {
         assertEquals(iae.getMessage(), "not a statement: result not used from addition operation [+]");
     }
 
+    public void testDefToVoidReturnThrowsException() {
+        ClassCastException exception = expectScriptThrows(
+            ClassCastException.class,
+            () -> getEngine().compile("def_return_in_void", "def x=1;return x;", VoidReturnTestScript.CONTEXT, Collections.emptyMap())
+        );
+        assertEquals(exception.getMessage(), "Cannot cast from [def] to [void].");
+    }
+
     public abstract static class FactoryTestConverterScript {
         private final Map<String, Object> params;
 
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionRefTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionRefTests.java
index 2ed1fa49d0bda..065e0fbd1f4e2 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionRefTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionRefTests.java
@@ -268,18 +268,16 @@ public void testInterfaceStaticMethod() {
     }
 
     public void testMethodMissing() {
-        Exception e = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = [2, 1]; l.sort(Integer::bogus); return l.get(0);"); }
-        );
+        Exception e = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = [2, 1]; l.sort(Integer::bogus); return l.get(0);");
+        });
         assertThat(e.getMessage(), containsString("function reference [Integer::bogus/2] matching [java.util.Comparator"));
     }
 
     public void testQualifiedMethodMissing() {
-        Exception e = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = [2, 1]; l.sort(java.time.Instant::bogus); return l.get(0);", false); }
-        );
+        Exception e = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = [2, 1]; l.sort(java.time.Instant::bogus); return l.get(0);", false);
+        });
         assertThat(
             e.getMessage(),
             containsString("function reference [java.time.Instant::bogus/2] matching [java.util.Comparator, compare/2")
@@ -287,26 +285,23 @@ public void testQualifiedMethodMissing() {
     }
 
     public void testClassMissing() {
-        Exception e = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = [2, 1]; l.sort(Bogus::bogus); return l.get(0);", false); }
-        );
+        Exception e = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = [2, 1]; l.sort(Bogus::bogus); return l.get(0);", false);
+        });
         assertThat(e.getMessage(), endsWith("variable [Bogus] is not defined"));
     }
 
     public void testQualifiedClassMissing() {
-        Exception e = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = [2, 1]; l.sort(org.joda.time.BogusDateTime::bogus); return l.get(0);", false); }
-        );
+        Exception e = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = [2, 1]; l.sort(org.joda.time.BogusDateTime::bogus); return l.get(0);", false);
+        });
         assertEquals("variable [org.joda.time.BogusDateTime] is not defined", e.getMessage());
     }
 
     public void testNotFunctionalInterface() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = new ArrayList(); l.add(2); l.add(1); l.add(Integer::bogus); return l.get(0);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = new ArrayList(); l.add(2); l.add(1); l.add(Integer::bogus); return l.get(0);");
+        });
         assertThat(
             expected.getMessage(),
             containsString("cannot convert function reference [Integer::bogus] to a non-functional interface [def]")
@@ -314,17 +309,15 @@ public void testNotFunctionalInterface() {
     }
 
     public void testIncompatible() {
-        expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("List l = new ArrayList(); l.add(2); l.add(1); l.sort(String::startsWith); return l.get(0);"); }
-        );
+        expectScriptThrows(ClassCastException.class, () -> {
+            exec("List l = new ArrayList(); l.add(2); l.add(1); l.sort(String::startsWith); return l.get(0);");
+        });
     }
 
     public void testWrongArity() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("Optional.empty().orElseGet(String::startsWith);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("Optional.empty().orElseGet(String::startsWith);");
+        });
         assertThat(
             expected.getMessage(),
             containsString("function reference [String::startsWith/0] matching [java.util.function.Supplier")
@@ -332,18 +325,16 @@ public void testWrongArity() {
     }
 
     public void testWrongArityNotEnough() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("List l = new ArrayList(); l.add(2); l.add(1); l.sort(String::isEmpty);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = new ArrayList(); l.add(2); l.add(1); l.sort(String::isEmpty);");
+        });
         assertThat(expected.getMessage(), containsString("function reference [String::isEmpty/2] matching [java.util.Comparator"));
     }
 
     public void testWrongArityDef() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def y = Optional.empty(); return y.orElseGet(String::startsWith);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def y = Optional.empty(); return y.orElseGet(String::startsWith);");
+        });
         assertThat(
             expected.getMessage(),
             containsString("function reference [String::startsWith/0] matching [java.util.function.Supplier")
@@ -351,38 +342,33 @@ public void testWrongArityDef() {
     }
 
     public void testWrongArityNotEnoughDef() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def l = new ArrayList(); l.add(2); l.add(1); l.sort(String::isEmpty);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def l = new ArrayList(); l.add(2); l.add(1); l.sort(String::isEmpty);");
+        });
         assertThat(expected.getMessage(), containsString("function reference [String::isEmpty/2] matching [java.util.Comparator"));
     }
 
     public void testReturnVoid() {
-        Throwable expected = expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("StringBuilder b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(b::setLength).sum();"); }
-        );
+        Throwable expected = expectScriptThrows(ClassCastException.class, () -> {
+            exec("StringBuilder b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(b::setLength).sum();");
+        });
         assertThat(expected.getMessage(), containsString("Cannot cast from [void] to [long]."));
     }
 
     public void testReturnVoidDef() {
-        Exception expected = expectScriptThrows(
-            LambdaConversionException.class,
-            () -> { exec("StringBuilder b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(b::setLength);"); }
-        );
+        Exception expected = expectScriptThrows(LambdaConversionException.class, () -> {
+            exec("StringBuilder b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(b::setLength);");
+        });
         assertThat(expected.getMessage(), containsString("lambda expects return type [long], but found return type [void]"));
 
-        expected = expectScriptThrows(
-            LambdaConversionException.class,
-            () -> { exec("def b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(b::setLength);"); }
-        );
+        expected = expectScriptThrows(LambdaConversionException.class, () -> {
+            exec("def b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(b::setLength);");
+        });
         assertThat(expected.getMessage(), containsString("lambda expects return type [long], but found return type [void]"));
 
-        expected = expectScriptThrows(
-            LambdaConversionException.class,
-            () -> { exec("def b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(b::setLength);"); }
-        );
+        expected = expectScriptThrows(LambdaConversionException.class, () -> {
+            exec("def b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(b::setLength);");
+        });
         assertThat(expected.getMessage(), containsString("lambda expects return type [long], but found return type [void]"));
     }
 }
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionTests.java
index 77b6e8f0b3d5c..45efaa2c8a5a4 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/FunctionTests.java
@@ -82,10 +82,9 @@ public void testReturnsAreUnboxedIfNeeded() {
     }
 
     public void testDuplicates() {
-        Exception expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("void test(int x) {x = 2;} void test(def y) {y = 3;} test()"); }
-        );
+        Exception expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("void test(int x) {x = 2;} void test(def y) {y = 3;} test()");
+        });
         assertThat(expected.getMessage(), containsString("found duplicate function"));
     }
 
@@ -108,23 +107,20 @@ public void testInfiniteLoop() {
 
     public void testReturnVoid() {
         assertEquals(null, exec("void test(StringBuilder b, int i) {b.setLength(i)} test(new StringBuilder(), 1)"));
-        Exception expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("int test(StringBuilder b, int i) {b.setLength(i)} test(new StringBuilder(), 1)"); }
-        );
+        Exception expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("int test(StringBuilder b, int i) {b.setLength(i)} test(new StringBuilder(), 1)");
+        });
         assertEquals(
             "invalid function definition: " + "not all paths provide a return value for function [test] with [2] parameters",
             expected.getMessage()
         );
-        expected = expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("int test(StringBuilder b, int i) {return b.setLength(i)} test(new StringBuilder(), 1)"); }
-        );
+        expected = expectScriptThrows(ClassCastException.class, () -> {
+            exec("int test(StringBuilder b, int i) {return b.setLength(i)} test(new StringBuilder(), 1)");
+        });
         assertEquals("Cannot cast from [void] to [int].", expected.getMessage());
-        expected = expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("def test(StringBuilder b, int i) {return b.setLength(i)} test(new StringBuilder(), 1)"); }
-        );
+        expected = expectScriptThrows(ClassCastException.class, () -> {
+            exec("def test(StringBuilder b, int i) {return b.setLength(i)} test(new StringBuilder(), 1)");
+        });
         assertEquals("Cannot cast from [void] to [def].", expected.getMessage());
     }
 }
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/GeneralCastTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/GeneralCastTests.java
index 225dbd51819de..27930e2cb43d8 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/GeneralCastTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/GeneralCastTests.java
@@ -293,14 +293,12 @@ public void testIllegalExplicitConversionsDef() {
     }
 
     public void testIllegalVoidCasts() {
-        expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def map = ['a': 1,'b': 2,'c': 3]; map.c = Collections.sort(new ArrayList(map.keySet()));"); }
-        );
-        expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("Map map = ['a': 1,'b': 2,'c': 3]; def x = new HashMap(); x.put(1, map.clear());"); }
-        );
+        expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def map = ['a': 1,'b': 2,'c': 3]; map.c = Collections.sort(new ArrayList(map.keySet()));");
+        });
+        expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("Map map = ['a': 1,'b': 2,'c': 3]; def x = new HashMap(); x.put(1, map.clear());");
+        });
     }
 
     public void testBoxedDefCalls() {
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/LambdaTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/LambdaTests.java
index c1b19522021b8..8d0cbb4018801 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/LambdaTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/LambdaTests.java
@@ -173,28 +173,19 @@ public void testTwoCaptures() {
     }
 
     public void testCapturesAreReadOnly() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> {
-                exec(
-                    "List l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(x -> { l = null; return x + 1 }).sum();"
-                );
-            }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("List l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(x -> { l = null; return x + 1 }).sum();");
+        });
         assertTrue(expected.getMessage().contains("is read-only"));
     }
 
     /** Lambda parameters shouldn't be able to mask a variable already in scope */
     public void testNoParamMasking() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> {
-                exec(
-                    "int x = 0; List l = new ArrayList(); l.add(1); l.add(1); "
-                        + "return l.stream().mapToInt(x -> { x += 1; return x }).sum();"
-                );
-            }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec(
+                "int x = 0; List l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(x -> { x += 1; return x }).sum();"
+            );
+        });
         assertTrue(expected.getMessage().contains("already defined"));
     }
 
@@ -214,36 +205,30 @@ public void testNestedCaptureParams() {
     }
 
     public void testWrongArity() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            false,
-            () -> { exec("Optional.empty().orElseGet(x -> x);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, false, () -> {
+            exec("Optional.empty().orElseGet(x -> x);");
+        });
         assertTrue(expected.getMessage().contains("Incorrect number of parameters"));
     }
 
     public void testWrongArityDef() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def y = Optional.empty(); return y.orElseGet(x -> x);"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def y = Optional.empty(); return y.orElseGet(x -> x);");
+        });
         assertTrue(expected.getMessage(), expected.getMessage().contains("due to an incorrect number of arguments"));
     }
 
     public void testWrongArityNotEnough() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            false,
-            () -> { exec("List l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(() -> 5).sum();"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, false, () -> {
+            exec("List l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(() -> 5).sum();");
+        });
         assertTrue(expected.getMessage().contains("Incorrect number of parameters"));
     }
 
     public void testWrongArityNotEnoughDef() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(() -> 5).sum();"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def l = new ArrayList(); l.add(1); l.add(1); " + "return l.stream().mapToInt(() -> 5).sum();");
+        });
         assertTrue(expected.getMessage(), expected.getMessage().contains("due to an incorrect number of arguments"));
     }
 
@@ -308,19 +293,17 @@ public void testReservedCapture() {
     }
 
     public void testReturnVoid() {
-        Throwable expected = expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("StringBuilder b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(i -> b.setLength(i))"); }
-        );
+        Throwable expected = expectScriptThrows(ClassCastException.class, () -> {
+            exec("StringBuilder b = new StringBuilder(); List l = [1, 2]; l.stream().mapToLong(i -> b.setLength(i))");
+        });
         assertThat(expected.getMessage(), containsString("Cannot cast from [void] to [long]."));
     }
 
     public void testReturnVoidDef() {
         // If we can catch the error at compile time we do
-        Exception expected = expectScriptThrows(
-            ClassCastException.class,
-            () -> { exec("StringBuilder b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(i -> b.setLength(i))"); }
-        );
+        Exception expected = expectScriptThrows(ClassCastException.class, () -> {
+            exec("StringBuilder b = new StringBuilder(); def l = [1, 2]; l.stream().mapToLong(i -> b.setLength(i))");
+        });
         assertThat(expected.getMessage(), containsString("Cannot cast from [void] to [def]."));
 
         // Otherwise we convert the void into a null
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/OverloadTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/OverloadTests.java
index 16f3c16a59548..02fa18ec07178 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/OverloadTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/OverloadTests.java
@@ -38,20 +38,18 @@ public class OverloadTests extends ScriptTestCase {
     public void testMethod() {
         // assertEquals(2, exec("return 'abc123abc'.indexOf('c');"));
         // assertEquals(8, exec("return 'abc123abc'.indexOf('c', 3);"));
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("return 'abc123abc'.indexOf('c', 3, 'bogus');"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("return 'abc123abc'.indexOf('c', 3, 'bogus');");
+        });
         assertTrue(expected.getMessage().contains("[java.lang.String, indexOf/3]"));
     }
 
     public void testMethodDynamic() {
         assertEquals(2, exec("def x = 'abc123abc'; return x.indexOf('c');"));
         assertEquals(8, exec("def x = 'abc123abc'; return x.indexOf('c', 3);"));
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def x = 'abc123abc'; return x.indexOf('c', 3, 'bogus');"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def x = 'abc123abc'; return x.indexOf('c', 3, 'bogus');");
+        });
         assertTrue(expected.getMessage().contains("dynamic method [java.lang.String, indexOf/3] not found"));
     }
 
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimit2Tests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimit2Tests.java
index 1d08fdac9c58c..b860c783a5c0d 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimit2Tests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimit2Tests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.painless;
 
+import org.opensearch.common.settings.Settings;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.opensearch.common.settings.Settings;
 
 public class RegexLimit2Tests extends ScriptTestCase {
     // This regex has backtracking due to .*?
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimitTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimitTests.java
index c3233bc0d924a..8a965e715f810 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimitTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexLimitTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.painless;
 
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.settings.Settings;
 
 import java.util.Collections;
 
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexTests.java
index 8c1f545efcf7a..628e15b9bb544 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/RegexTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/RegexTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.painless;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.script.ScriptException;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.nio.CharBuffer;
 import java.util.Arrays;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptTestCase.java b/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptTestCase.java
index a30aa97d33461..0bf7bf527bcd1 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptTestCase.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptTestCase.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.painless;
 
-import junit.framework.AssertionFailedError;
-
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.antlr.Walker;
 import org.opensearch.painless.spi.Whitelist;
@@ -48,8 +46,10 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.hamcrest.Matchers.hasSize;
+import junit.framework.AssertionFailedError;
+
 import static org.opensearch.painless.action.PainlessExecuteAction.PainlessTestScript;
+import static org.hamcrest.Matchers.hasSize;
 
 /**
  * Base test case for scripting unit tests.
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptedMetricAggContextsTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptedMetricAggContextsTests.java
index af28a3f850d0a..5a7e672da6bd6 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptedMetricAggContextsTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/ScriptedMetricAggContextsTests.java
@@ -35,8 +35,6 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.memory.MemoryIndex;
 import org.apache.lucene.search.Scorable;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.script.ScriptContext;
@@ -44,6 +42,8 @@
 import org.opensearch.search.lookup.LeafSearchLookup;
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.search.lookup.SourceLookup;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/SimilarityScriptTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/SimilarityScriptTests.java
index 9b404853cf7b5..3c28183d05171 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/SimilarityScriptTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/SimilarityScriptTests.java
@@ -49,14 +49,14 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.Directory;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.similarity.ScriptedSimilarity;
 import org.opensearch.painless.spi.Whitelist;
 import org.opensearch.script.ScriptContext;
 import org.opensearch.script.SimilarityScript;
 import org.opensearch.script.SimilarityWeightScript;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/StringTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/StringTests.java
index d344a9c2a31f1..b9586924d4fcd 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/StringTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/StringTests.java
@@ -182,11 +182,9 @@ public void testStringAndCharacter() {
         assertEquals('c', exec("String s = \"c\"; (char)s"));
         assertEquals('c', exec("String s = 'c'; (char)s"));
 
-        ClassCastException expected = expectScriptThrows(
-            ClassCastException.class,
-            false,
-            () -> { assertEquals("cc", exec("return (String)(char)\"cc\"")); }
-        );
+        ClassCastException expected = expectScriptThrows(ClassCastException.class, false, () -> {
+            assertEquals("cc", exec("return (String)(char)\"cc\""));
+        });
         assertTrue(expected.getMessage().contains("cannot cast java.lang.String with length not equal to one to char"));
 
         expected = expectScriptThrows(ClassCastException.class, false, () -> { assertEquals("cc", exec("return (String)(char)'cc'")); });
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/WhenThingsGoWrongTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/WhenThingsGoWrongTests.java
index fb8d2eccfa043..0d498e16154c8 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/WhenThingsGoWrongTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/WhenThingsGoWrongTests.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.painless;
 
-import junit.framework.AssertionFailedError;
 import org.apache.lucene.util.Constants;
 import org.opensearch.script.ScriptException;
 
 import java.lang.invoke.WrongMethodTypeException;
 import java.util.Collections;
 
+import junit.framework.AssertionFailedError;
+
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static org.hamcrest.Matchers.instanceOf;
@@ -57,10 +58,9 @@ public void testNullPointer() {
     public void testScriptStack() {
         for (String type : new String[] { "String", "def   " }) {
             // trigger NPE at line 1 of the script
-            ScriptException exception = expectThrows(
-                ScriptException.class,
-                () -> { exec(type + " x = null; boolean y = x.isEmpty();\n" + "return y;"); }
-            );
+            ScriptException exception = expectThrows(ScriptException.class, () -> {
+                exec(type + " x = null; boolean y = x.isEmpty();\n" + "return y;");
+            });
             // null deref at x.isEmpty(), the '.' is offset 30
             assertScriptElementColumn(30, exception);
             assertScriptStack(exception, "y = x.isEmpty();\n", "     ^---- HERE");
@@ -84,12 +84,9 @@ public void testScriptStack() {
             assertThat(exception.getCause(), instanceOf(NullPointerException.class));
 
             // trigger NPE at line 4 in script (inside conditional)
-            exception = expectThrows(
-                ScriptException.class,
-                () -> {
-                    exec(type + " x = null;\n" + "boolean y = false;\n" + "if (!y) {\n" + "  y = x.isEmpty();\n" + "}\n" + "return y;");
-                }
-            );
+            exception = expectThrows(ScriptException.class, () -> {
+                exec(type + " x = null;\n" + "boolean y = false;\n" + "if (!y) {\n" + "  y = x.isEmpty();\n" + "}\n" + "return y;");
+            });
             // null deref at x.isEmpty(), the '.' is offset 53
             assertScriptElementColumn(53, exception);
             assertScriptStack(exception, "y = x.isEmpty();\n}\n", "     ^---- HERE");
@@ -121,10 +118,9 @@ public void testInvalidShift() {
     }
 
     public void testBogusParameter() {
-        IllegalArgumentException expected = expectThrows(
-            IllegalArgumentException.class,
-            () -> { exec("return 5;", null, Collections.singletonMap("bogusParameterKey", "bogusParameterValue"), true); }
-        );
+        IllegalArgumentException expected = expectThrows(IllegalArgumentException.class, () -> {
+            exec("return 5;", null, Collections.singletonMap("bogusParameterKey", "bogusParameterValue"), true);
+        });
         assertTrue(expected.getMessage().contains("Unrecognized compile-time parameter"));
     }
 
@@ -178,10 +174,9 @@ public void testLoopLimits() {
     }
 
     public void testIllegalDynamicMethod() {
-        IllegalArgumentException expected = expectScriptThrows(
-            IllegalArgumentException.class,
-            () -> { exec("def x = 'test'; return x.getClass().toString()"); }
-        );
+        IllegalArgumentException expected = expectScriptThrows(IllegalArgumentException.class, () -> {
+            exec("def x = 'test'; return x.getClass().toString()");
+        });
         assertTrue(expected.getMessage().contains("dynamic method [java.lang.String, getClass/0] not found"));
     }
 
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/WhitelistLoaderTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/WhitelistLoaderTests.java
index e4e754a541414..b7ba3040894e3 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/WhitelistLoaderTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/WhitelistLoaderTests.java
@@ -47,19 +47,15 @@ public class WhitelistLoaderTests extends ScriptTestCase {
     public void testUnknownAnnotations() {
         Map<String, WhitelistAnnotationParser> parsers = new HashMap<>(WhitelistAnnotationParser.BASE_ANNOTATION_PARSERS);
 
-        RuntimeException expected = expectThrows(
-            RuntimeException.class,
-            () -> { WhitelistLoader.loadFromResourceFiles(Whitelist.class, parsers, "org.opensearch.painless.annotation.unknown"); }
-        );
+        RuntimeException expected = expectThrows(RuntimeException.class, () -> {
+            WhitelistLoader.loadFromResourceFiles(Whitelist.class, parsers, "org.opensearch.painless.annotation.unknown");
+        });
         assertEquals("invalid annotation: parser not found for [unknownAnnotation] [@unknownAnnotation]", expected.getCause().getMessage());
         assertEquals(IllegalArgumentException.class, expected.getCause().getClass());
 
-        expected = expectThrows(
-            RuntimeException.class,
-            () -> {
-                WhitelistLoader.loadFromResourceFiles(Whitelist.class, parsers, "org.opensearch.painless.annotation.unknown_with_options");
-            }
-        );
+        expected = expectThrows(RuntimeException.class, () -> {
+            WhitelistLoader.loadFromResourceFiles(Whitelist.class, parsers, "org.opensearch.painless.annotation.unknown_with_options");
+        });
         assertEquals(
             "invalid annotation: parser not found for [unknownAnootationWithMessage] [@unknownAnootationWithMessage[arg=\"arg value\"]]",
             expected.getCause().getMessage()
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/action/ContextInfoTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/action/ContextInfoTests.java
index 9e3f8794b9cbc..b576a65db61df 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/action/ContextInfoTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/action/ContextInfoTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.util.ArrayList;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteApiTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteApiTests.java
index 424d88cbc9e00..7840f7b010abc 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteApiTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteApiTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.painless.PainlessPlugin;
@@ -92,13 +92,13 @@ public void testFilterExecutionContext() throws IOException {
         IndexService indexService = createIndex("index", Settings.EMPTY, "doc", "field", "type=long");
 
         Request.ContextSetup contextSetup = new Request.ContextSetup("index", new BytesArray("{\"field\": 3}"), null);
-        contextSetup.setXContentType(XContentType.JSON);
+        contextSetup.setXContentType(MediaTypeRegistry.JSON);
         Request request = new Request(new Script("doc['field'].value >= 3"), "filter", contextSetup);
         Response response = innerShardOperation(request, scriptService, indexService);
         assertThat(response.getResult(), equalTo(true));
 
         contextSetup = new Request.ContextSetup("index", new BytesArray("{\"field\": 3}"), null);
-        contextSetup.setXContentType(XContentType.JSON);
+        contextSetup.setXContentType(MediaTypeRegistry.JSON);
         request = new Request(
             new Script(ScriptType.INLINE, "painless", "doc['field'].value >= params.max", singletonMap("max", 3)),
             "filter",
@@ -108,7 +108,7 @@ public void testFilterExecutionContext() throws IOException {
         assertThat(response.getResult(), equalTo(true));
 
         contextSetup = new Request.ContextSetup("index", new BytesArray("{\"field\": 2}"), null);
-        contextSetup.setXContentType(XContentType.JSON);
+        contextSetup.setXContentType(MediaTypeRegistry.JSON);
         request = new Request(
             new Script(ScriptType.INLINE, "painless", "doc['field'].value >= params.max", singletonMap("max", 3)),
             "filter",
@@ -127,7 +127,7 @@ public void testScoreExecutionContext() throws IOException {
             new BytesArray("{\"rank\": 4.0, \"text\": \"quick brown fox\"}"),
             new MatchQueryBuilder("text", "fox")
         );
-        contextSetup.setXContentType(XContentType.JSON);
+        contextSetup.setXContentType(MediaTypeRegistry.JSON);
         Request request = new Request(
             new Script(
                 ScriptType.INLINE,
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteRequestTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteRequestTests.java
index 0c3bb95bdadc3..661c12a111eb7 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteRequestTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteRequestTests.java
@@ -31,17 +31,17 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.painless.action.PainlessExecuteAction.Request.ContextSetup;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteResponseTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteResponseTests.java
index db2da58894e70..9c9ba090685ec 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteResponseTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/action/PainlessExecuteResponseTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.painless.action;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/modules/lang-painless/src/test/java/org/opensearch/painless/api/LimitedCharSequenceTests.java b/modules/lang-painless/src/test/java/org/opensearch/painless/api/LimitedCharSequenceTests.java
index a7787f4bc3c29..4117eb331197f 100644
--- a/modules/lang-painless/src/test/java/org/opensearch/painless/api/LimitedCharSequenceTests.java
+++ b/modules/lang-painless/src/test/java/org/opensearch/painless/api/LimitedCharSequenceTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.painless.api;
 
-import org.opensearch.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.regex.Pattern;
diff --git a/modules/lang-painless/src/yamlRestTest/java/org/opensearch/painless/LangPainlessClientYamlTestSuiteIT.java b/modules/lang-painless/src/yamlRestTest/java/org/opensearch/painless/LangPainlessClientYamlTestSuiteIT.java
index 520c656723177..f83a8929d979d 100644
--- a/modules/lang-painless/src/yamlRestTest/java/org/opensearch/painless/LangPainlessClientYamlTestSuiteIT.java
+++ b/modules/lang-painless/src/yamlRestTest/java/org/opensearch/painless/LangPainlessClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/100_terms_agg.yml b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/100_terms_agg.yml
index 000e1af694d7d..aa01647811c83 100644
--- a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/100_terms_agg.yml
+++ b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/100_terms_agg.yml
@@ -139,4 +139,3 @@ setup:
   - is_false: aggregations.placeholder.buckets.0.str_terms.buckets.1.key_as_string
   - match: { aggregations.placeholder.buckets.0.str_terms.buckets.1.doc_count: 1 }
   - match: { aggregations.placeholder.buckets.0.the_bucket_script.value: 2.0 }
-
diff --git a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/10_basic.yml b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/10_basic.yml
index e442b40ffb845..a2458269b7aa1 100644
--- a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/10_basic.yml
+++ b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: lang-painless } }
+    - contains:  { nodes.$cluster_manager.modules: { name: lang-painless } }
diff --git a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/120_script_score_term_frequency.yml b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/120_script_score_term_frequency.yml
new file mode 100644
index 0000000000000..b3ff66251938d
--- /dev/null
+++ b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/120_script_score_term_frequency.yml
@@ -0,0 +1,95 @@
+---
+setup:
+  - skip:
+      version: " - 2.9.99"
+      reason: "termFreq functions for script_score was introduced in 2.10.0"
+  - do:
+      indices.create:
+        index: test
+        body:
+          settings:
+            number_of_shards: 1
+          mappings:
+            properties:
+              f1:
+                type: keyword
+              f2:
+                type: text
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - '{"index": {"_index": "test", "_id": "doc1"}}'
+          - '{"f1": "v0", "f2": "v1"}'
+          - '{"index": {"_index": "test", "_id": "doc2"}}'
+          - '{"f2": "v2"}'
+
+---
+"Script score function using the termFreq function":
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          query:
+            function_score:
+              query:
+                match_all: {}
+              script_score:
+                script:
+                  source: "termFreq(params.field, params.term)"
+                  params:
+                    field: "f1"
+                    term: "v0"
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._id: "doc1" }
+  - match: { hits.hits.1._id: "doc2" }
+  - match: { hits.hits.0._score: 1.0 }
+  - match: { hits.hits.1._score: 0.0 }
+
+---
+"Script score function using the totalTermFreq function":
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          query:
+            function_score:
+              query:
+                match_all: {}
+              script_score:
+                script:
+                  source: "if (doc[params.field].size() == 0) return params.default_value; else { return totalTermFreq(params.field, params.term); }"
+                  params:
+                    default_value: 0.5
+                    field: "f1"
+                    term: "v0"
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._id: "doc1" }
+  - match: { hits.hits.1._id: "doc2" }
+  - match: { hits.hits.0._score: 1.0 }
+  - match: { hits.hits.1._score: 0.5 }
+
+---
+"Script score function using the sumTotalTermFreq function":
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          query:
+            function_score:
+              query:
+                match_all: {}
+              script_score:
+                script:
+                  source: "if (doc[params.field].size() == 0) return params.default_value; else { return sumTotalTermFreq(params.field); }"
+                  params:
+                    default_value: 0.5
+                    field: "f1"
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._id: "doc1" }
+  - match: { hits.hits.1._id: "doc2" }
+  - match: { hits.hits.0._score: 1.0 }
+  - match: { hits.hits.1._score: 0.5 }
diff --git a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/71_context_api.yml b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/71_context_api.yml
index 0413661fc586c..478ca9ae8abf4 100644
--- a/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/71_context_api.yml
+++ b/modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/71_context_api.yml
@@ -2,7 +2,7 @@
     - do:
         scripts_painless_context: {}
     - match: { contexts.0: aggregation_selector}
-    - match: { contexts.22: update}
+    - match: { contexts.23: update}
 ---
 
 "Action to get all API values for score context":
diff --git a/modules/mapper-extras/src/javaRestTest/java/org/opensearch/index/mapper/TokenCountFieldMapperIntegrationIT.java b/modules/mapper-extras/src/javaRestTest/java/org/opensearch/index/mapper/TokenCountFieldMapperIntegrationIT.java
index e25344a4bb4e3..bd0795f07139b 100644
--- a/modules/mapper-extras/src/javaRestTest/java/org/opensearch/index/mapper/TokenCountFieldMapperIntegrationIT.java
+++ b/modules/mapper-extras/src/javaRestTest/java/org/opensearch/index/mapper/TokenCountFieldMapperIntegrationIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkResponse;
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeatureFieldMapper.java b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeatureFieldMapper.java
index 31fef7301477a..42e7d9933dd61 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeatureFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeatureFieldMapper.java
@@ -39,7 +39,7 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.lookup.SearchLookup;
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeaturesFieldMapper.java b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeaturesFieldMapper.java
index 43853eb40f432..8c2fc705c4b52 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeaturesFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/RankFeaturesFieldMapper.java
@@ -36,13 +36,12 @@
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.search.Query;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
@@ -55,8 +54,18 @@ public class RankFeaturesFieldMapper extends ParametrizedFieldMapper {
 
     public static final String CONTENT_TYPE = "rank_features";
 
+    private static RankFeaturesFieldType ft(FieldMapper in) {
+        return ((RankFeaturesFieldMapper) in).fieldType();
+    }
+
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
+        private final Parameter<Boolean> positiveScoreImpact = Parameter.boolParam(
+            "positive_score_impact",
+            false,
+            m -> ft(m).positiveScoreImpact,
+            true
+        );
         private final Parameter<Map<String, String>> meta = Parameter.metaParam();
 
         public Builder(String name) {
@@ -66,16 +75,17 @@ public Builder(String name) {
 
         @Override
         protected List<Parameter<?>> getParameters() {
-            return Collections.singletonList(meta);
+            return List.of(meta, positiveScoreImpact);
         }
 
         @Override
         public RankFeaturesFieldMapper build(BuilderContext context) {
             return new RankFeaturesFieldMapper(
                 name,
-                new RankFeaturesFieldType(buildFullName(context), meta.getValue()),
+                new RankFeaturesFieldType(buildFullName(context), meta.getValue(), positiveScoreImpact.getValue()),
                 multiFieldsBuilder.build(this, context),
-                copyTo.build()
+                copyTo.build(),
+                positiveScoreImpact.getValue()
             );
         }
     }
@@ -84,9 +94,12 @@ public RankFeaturesFieldMapper build(BuilderContext context) {
 
     public static final class RankFeaturesFieldType extends MappedFieldType {
 
-        public RankFeaturesFieldType(String name, Map<String, String> meta) {
+        private final boolean positiveScoreImpact;
+
+        public RankFeaturesFieldType(String name, Map<String, String> meta, boolean positiveScoreImpact) {
             super(name, false, false, false, TextSearchInfo.NONE, meta);
             setIndexAnalyzer(Lucene.KEYWORD_ANALYZER);
+            this.positiveScoreImpact = positiveScoreImpact;
         }
 
         @Override
@@ -94,6 +107,10 @@ public String typeName() {
             return CONTENT_TYPE;
         }
 
+        public boolean positiveScoreImpact() {
+            return positiveScoreImpact;
+        }
+
         @Override
         public Query existsQuery(QueryShardContext context) {
             throw new IllegalArgumentException("[rank_features] fields do not support [exists] queries");
@@ -115,9 +132,18 @@ public Query termQuery(Object value, QueryShardContext context) {
         }
     }
 
-    private RankFeaturesFieldMapper(String simpleName, MappedFieldType mappedFieldType, MultiFields multiFields, CopyTo copyTo) {
+    private final boolean positiveScoreImpact;
+
+    private RankFeaturesFieldMapper(
+        String simpleName,
+        MappedFieldType mappedFieldType,
+        MultiFields multiFields,
+        CopyTo copyTo,
+        boolean positiveScoreImpact
+    ) {
         super(simpleName, mappedFieldType, multiFields, copyTo);
         assert fieldType.indexOptions().compareTo(IndexOptions.DOCS_AND_FREQS) <= 0;
+        this.positiveScoreImpact = positiveScoreImpact;
     }
 
     @Override
@@ -164,6 +190,9 @@ public void parse(ParseContext context) throws IOException {
                             + "] in the same document"
                     );
                 }
+                if (positiveScoreImpact == false) {
+                    value = 1 / value;
+                }
                 context.doc().addWithKey(key, new FeatureField(name(), feature, value));
             } else {
                 throw new IllegalArgumentException(
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/ScaledFloatFieldMapper.java b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/ScaledFloatFieldMapper.java
index 78a9e389eb63f..7be241017f683 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/ScaledFloatFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/ScaledFloatFieldMapper.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.index.mapper;
 
+import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.LeafReaderContext;
@@ -43,9 +45,9 @@
 import org.opensearch.common.Explicit;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
@@ -392,7 +394,7 @@ protected void parseCreateField(ParseContext context) throws IOException {
         } else {
             try {
                 numericValue = parse(parser, coerce.value());
-            } catch (IllegalArgumentException e) {
+            } catch (IllegalArgumentException | JsonParseException e) {
                 if (ignoreMalformed.value()) {
                     return;
                 } else {
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapper.java b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapper.java
index 7394993448bbf..397a7b48b472a 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapper.java
@@ -60,6 +60,7 @@
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.Operations;
 import org.opensearch.common.collect.Iterators;
+import org.opensearch.common.lucene.search.AutomatonQueries;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -204,8 +205,8 @@ public SearchAsYouTypeFieldMapper build(Mapper.BuilderContext context) {
             ft.setIndexAnalyzer(analyzers.getIndexAnalyzer());
 
             // set up the prefix field
-            FieldType prefixft = new FieldType(fieldType);
-            prefixft.setStoreTermVectors(false);
+            FieldType prefixft = new FieldType();
+            prefixft.setIndexOptions(fieldType.indexOptions());
             prefixft.setOmitNorms(true);
             prefixft.setStored(false);
             final String fullName = buildFullName(context);
@@ -431,8 +432,7 @@ public Query prefixQuery(String value, MultiTermQuery.RewriteMethod method, bool
                 automata.add(Automata.makeAnyChar());
             }
             Automaton automaton = Operations.concatenate(automata);
-            AutomatonQuery query = new AutomatonQuery(new Term(name(), value + "*"), automaton);
-            query.setRewriteMethod(method);
+            AutomatonQuery query = AutomatonQueries.createAutomatonQuery(new Term(name(), value + "*"), automaton, method);
             return new BooleanQuery.Builder().add(query, BooleanClause.Occur.SHOULD)
                 .add(new TermQuery(new Term(parentField, value)), BooleanClause.Occur.SHOULD)
                 .build();
@@ -618,7 +618,7 @@ public SpanQuery spanPrefixQuery(String value, SpanMultiTermQueryWrapper.SpanRew
     private final PrefixFieldMapper prefixField;
     private final ShingleFieldMapper[] shingleFields;
 
-    private final Builder builder;
+    private final IndexAnalyzers indexAnalyzers;
 
     public SearchAsYouTypeFieldMapper(
         String simpleName,
@@ -636,7 +636,7 @@ public SearchAsYouTypeFieldMapper(
         this.store = builder.store.getValue();
         this.indexOptions = builder.indexOptions.getValue();
         this.termVectors = builder.termVectors.getValue();
-        this.builder = builder;
+        this.indexAnalyzers = builder.analyzers.indexAnalyzers;
     }
 
     @Override
@@ -663,7 +663,7 @@ protected String contentType() {
 
     @Override
     public ParametrizedFieldMapper.Builder getMergeBuilder() {
-        return new Builder(simpleName(), builder.analyzers.indexAnalyzers).init(this);
+        return new Builder(simpleName(), this.indexAnalyzers).init(this);
     }
 
     public static String getShingleFieldName(String parentField, int shingleSize) {
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/TokenCountFieldMapper.java b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/TokenCountFieldMapper.java
index fd029503e9a7b..1851afcf0af85 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/TokenCountFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/mapper/TokenCountFieldMapper.java
@@ -122,7 +122,7 @@ static class TokenCountFieldType extends NumberFieldMapper.NumberFieldType {
         @Override
         public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchLookup, String format) {
             if (hasDocValues() == false) {
-                return lookup -> org.opensearch.common.collect.List.of();
+                return lookup -> List.of();
             }
             return new DocValueFetcher(docValueFormat(format, null), searchLookup.doc().getForField(this));
         }
diff --git a/modules/mapper-extras/src/main/java/org/opensearch/index/query/RankFeatureQueryBuilder.java b/modules/mapper-extras/src/main/java/org/opensearch/index/query/RankFeatureQueryBuilder.java
index 9ad52c805da9d..13591d0782ea2 100644
--- a/modules/mapper-extras/src/main/java/org/opensearch/index/query/RankFeatureQueryBuilder.java
+++ b/modules/mapper-extras/src/main/java/org/opensearch/index/query/RankFeatureQueryBuilder.java
@@ -35,16 +35,16 @@
 import org.apache.lucene.document.FeatureField;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.RankFeatureFieldMapper.RankFeatureFieldType;
 import org.opensearch.index.mapper.RankFeatureMetaFieldMapper;
 import org.opensearch.index.mapper.RankFeaturesFieldMapper.RankFeaturesFieldType;
-import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/BWCTemplateTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/BWCTemplateTests.java
index d9e40fac1ad0f..bb944de2468aa 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/BWCTemplateTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/BWCTemplateTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
@@ -54,9 +54,9 @@ public void testBeatsTemplatesBWC() throws Exception {
         byte[] metricBeat = copyToBytesFromClasspath("/org/opensearch/index/mapper/metricbeat-6.0.template.json");
         byte[] packetBeat = copyToBytesFromClasspath("/org/opensearch/index/mapper/packetbeat-6.0.template.json");
         byte[] fileBeat = copyToBytesFromClasspath("/org/opensearch/index/mapper/filebeat-6.0.template.json");
-        client().admin().indices().preparePutTemplate("metricbeat").setSource(metricBeat, XContentType.JSON).get();
-        client().admin().indices().preparePutTemplate("packetbeat").setSource(packetBeat, XContentType.JSON).get();
-        client().admin().indices().preparePutTemplate("filebeat").setSource(fileBeat, XContentType.JSON).get();
+        client().admin().indices().preparePutTemplate("metricbeat").setSource(metricBeat, MediaTypeRegistry.JSON).get();
+        client().admin().indices().preparePutTemplate("packetbeat").setSource(packetBeat, MediaTypeRegistry.JSON).get();
+        client().admin().indices().preparePutTemplate("filebeat").setSource(fileBeat, MediaTypeRegistry.JSON).get();
 
         client().prepareIndex("metricbeat-foo").setId("1").setSource("message", "foo").get();
         client().prepareIndex("packetbeat-foo").setId("1").setSource("message", "foo").get();
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureFieldMapperTests.java
index 908e5db6196c3..f0bd69df0e35e 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureFieldMapperTests.java
@@ -38,14 +38,13 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.List;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
 
 import static org.hamcrest.Matchers.instanceOf;
 
@@ -91,7 +90,7 @@ protected void minimalMapping(XContentBuilder b) throws IOException {
 
     public void testDefaults() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
-        assertEquals(Strings.toString(fieldMapping(this::minimalMapping)), mapper.mappingSource().toString());
+        assertEquals(fieldMapping(this::minimalMapping).toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc1 = mapper.parse(source(b -> b.field("field", 10)));
         IndexableField[] fields = doc1.rootDoc().getFields("_feature");
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureMetaFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureMetaFieldMapperTests.java
index 3161e7462d2a0..0ae261936a225 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureMetaFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeatureMetaFieldMapperTests.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -61,18 +59,17 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testBasics() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "rank_feature")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = MediaTypeRegistry.JSON.contentBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "rank_feature")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
@@ -85,13 +82,15 @@ public void testBasics() throws Exception {
      * and parsing of a document fails if the document contains these meta-fields.
      */
     public void testDocumentParsingFailsOnMetaField() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("_doc").endObject().endObject());
+        String mapping = MediaTypeRegistry.JSON.contentBuilder().startObject().startObject("_doc").endObject().endObject().toString();
         DocumentMapper mapper = parser.parse("_doc", new CompressedXContent(mapping));
         String rfMetaField = RankFeatureMetaFieldMapper.CONTENT_TYPE;
-        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(rfMetaField, 0).endObject());
+        BytesReference bytes = BytesReference.bytes(
+            MediaTypeRegistry.JSON.contentBuilder().startObject().field(rfMetaField, 0).endObject()
+        );
         MapperParsingException e = expectThrows(
             MapperParsingException.class,
-            () -> mapper.parse(new SourceToParse("test", "1", bytes, XContentType.JSON))
+            () -> mapper.parse(new SourceToParse("test", "1", bytes, MediaTypeRegistry.JSON))
         );
         assertTrue(
             e.getCause().getMessage().contains("Field [" + rfMetaField + "] is a metadata field and cannot be added inside a document.")
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldMapperTests.java
index 129ba6b126237..0773bdedf806a 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldMapperTests.java
@@ -34,14 +34,14 @@
 
 import org.apache.lucene.document.FeatureField;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
 
 public class RankFeaturesFieldMapperTests extends MapperTestCase {
 
@@ -58,7 +58,7 @@ protected void assertExistsQuery(MapperService mapperService) {
 
     @Override
     protected Collection<? extends Plugin> getPlugins() {
-        return org.opensearch.common.collect.List.of(new MapperExtrasPlugin());
+        return List.of(new MapperExtrasPlugin());
     }
 
     @Override
@@ -67,8 +67,8 @@ protected void minimalMapping(XContentBuilder b) throws IOException {
     }
 
     @Override
-    protected void registerParameters(ParameterChecker checker) {
-        // no parameters to configure
+    protected void registerParameters(ParameterChecker checker) throws IOException {
+        checker.registerConflictCheck("positive_score_impact", b -> b.field("positive_score_impact", false));
     }
 
     @Override
@@ -78,7 +78,7 @@ protected boolean supportsMeta() {
 
     public void testDefaults() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
-        assertEquals(Strings.toString(fieldMapping(this::minimalMapping)), mapper.mappingSource().toString());
+        assertEquals(fieldMapping(this::minimalMapping).toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc1 = mapper.parse(source(this::writeField));
 
@@ -95,6 +95,33 @@ public void testDefaults() throws Exception {
         assertTrue(freq1 < freq2);
     }
 
+    public void testNegativeScoreImpact() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(
+            fieldMapping(b -> b.field("type", "rank_features").field("positive_score_impact", false))
+        );
+
+        ParsedDocument doc1 = mapper.parse(source(this::writeField));
+
+        IndexableField[] fields = doc1.rootDoc().getFields("field");
+        assertEquals(2, fields.length);
+        assertThat(fields[0], Matchers.instanceOf(FeatureField.class));
+        FeatureField featureField1 = null;
+        FeatureField featureField2 = null;
+        for (IndexableField field : fields) {
+            if (field.stringValue().equals("foo")) {
+                featureField1 = (FeatureField) field;
+            } else if (field.stringValue().equals("bar")) {
+                featureField2 = (FeatureField) field;
+            } else {
+                throw new UnsupportedOperationException();
+            }
+        }
+
+        int freq1 = RankFeatureFieldMapperTests.getFrequency(featureField1.tokenStream(null, null));
+        int freq2 = RankFeatureFieldMapperTests.getFrequency(featureField2.tokenStream(null, null));
+        assertTrue(freq1 > freq2);
+    }
+
     public void testRejectMultiValuedFields() throws MapperParsingException, IOException {
         DocumentMapper mapper = createDocumentMapper(mapping(b -> {
             b.startObject("field").field("type", "rank_features").endObject();
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldTypeTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldTypeTests.java
index b8c653bc97ce7..8ece0d63f05ba 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldTypeTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/RankFeaturesFieldTypeTests.java
@@ -37,7 +37,7 @@
 public class RankFeaturesFieldTypeTests extends FieldTypeTestCase {
 
     public void testIsNotAggregatable() {
-        MappedFieldType fieldType = new RankFeaturesFieldMapper.RankFeaturesFieldType("field", Collections.emptyMap());
+        MappedFieldType fieldType = new RankFeaturesFieldMapper.RankFeaturesFieldType("field", Collections.emptyMap(), true);
         assertFalse(fieldType.isAggregatable());
     }
 }
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldMapperTests.java
index 3de322b286183..7cb951ae73844 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldMapperTests.java
@@ -34,11 +34,10 @@
 
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 
 import java.io.IOException;
@@ -95,7 +94,7 @@ public void testExistsQueryDocValuesDisabled() throws IOException {
     public void testDefaults() throws Exception {
         XContentBuilder mapping = fieldMapping(b -> b.field("type", "scaled_float").field("scaling_factor", 10.0));
         DocumentMapper mapper = createDocumentMapper(mapping);
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("field", 123)));
         IndexableField[] fields = doc.rootDoc().getFields("field");
@@ -136,7 +135,7 @@ public void testNotIndexed() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", 123).endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -157,7 +156,7 @@ public void testNoDocValues() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", 123).endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -178,7 +177,7 @@ public void testStore() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", 123).endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -201,7 +200,7 @@ public void testCoerce() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "123").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = doc.rootDoc().getFields("field");
@@ -220,7 +219,7 @@ public void testCoerce() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "123").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         MapperParsingException e = expectThrows(MapperParsingException.class, runnable);
@@ -229,6 +228,7 @@ public void testCoerce() throws Exception {
 
     public void testIgnoreMalformed() throws Exception {
         doTestIgnoreMalformed("a", "For input string: \"a\"");
+        doTestIgnoreMalformed(true, "Current token (VALUE_TRUE) not numeric");
 
         List<String> values = Arrays.asList("NaN", "Infinity", "-Infinity");
         for (String value : values) {
@@ -236,14 +236,14 @@ public void testIgnoreMalformed() throws Exception {
         }
     }
 
-    private void doTestIgnoreMalformed(String value, String exceptionMessageContains) throws Exception {
+    private void doTestIgnoreMalformed(Object value, String exceptionMessageContains) throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
         ThrowingRunnable runnable = () -> mapper.parse(
             new SourceToParse(
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", value).endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         MapperParsingException e = expectThrows(MapperParsingException.class, runnable);
@@ -257,7 +257,7 @@ private void doTestIgnoreMalformed(String value, String exceptionMessageContains
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", value).endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -272,7 +272,7 @@ public void testNullValue() throws IOException {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().nullField("field").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field"));
@@ -285,7 +285,7 @@ public void testNullValue() throws IOException {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().nullField("field").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = doc.rootDoc().getFields("field");
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldTypeTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldTypeTests.java
index 0baf3db32a4d8..be12c49321b87 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldTypeTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/ScaledFloatFieldTypeTests.java
@@ -45,7 +45,7 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapperTests.java
index 786791314692d..26803c8548e24 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapperTests.java
@@ -50,9 +50,10 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.Strings;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -75,6 +76,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -133,7 +135,7 @@ protected void writeFieldValue(XContentBuilder builder) throws IOException {
 
     @Override
     protected Collection<? extends Plugin> getPlugins() {
-        return org.opensearch.common.collect.List.of(new MapperExtrasPlugin());
+        return List.of(new MapperExtrasPlugin());
     }
 
     @Override
@@ -149,20 +151,9 @@ protected IndexAnalyzers createIndexAnalyzers(IndexSettings indexSettings) {
         NamedAnalyzer simple = new NamedAnalyzer("simple", AnalyzerScope.INDEX, new SimpleAnalyzer());
         NamedAnalyzer whitespace = new NamedAnalyzer("whitespace", AnalyzerScope.INDEX, new WhitespaceAnalyzer());
         return new IndexAnalyzers(
-            org.opensearch.common.collect.Map.of(
-                "default",
-                dflt,
-                "standard",
-                standard,
-                "keyword",
-                keyword,
-                "simple",
-                simple,
-                "whitespace",
-                whitespace
-            ),
-            org.opensearch.common.collect.Map.of(),
-            org.opensearch.common.collect.Map.of()
+            Map.of("default", dflt, "standard", standard, "keyword", keyword, "simple", simple, "whitespace", whitespace),
+            Map.of(),
+            Map.of()
         );
     }
 
@@ -352,15 +343,30 @@ public void testIndex() throws IOException {
     }
 
     public void testTermVectors() throws IOException {
-        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "search_as_you_type").field("term_vector", "yes")));
+        String[] termVectors = {
+            "yes",
+            "with_positions",
+            "with_offsets",
+            "with_positions_offsets",
+            "with_positions_payloads",
+            "with_positions_offsets_payloads" };
+
+        for (String termVector : termVectors) {
+            DocumentMapper mapper = createDocumentMapper(
+                fieldMapping(b -> b.field("type", "search_as_you_type").field("term_vector", termVector))
+            );
 
-        assertTrue(getRootFieldMapper(mapper, "field").fieldType().fieldType.storeTermVectors());
+            assertTrue(getRootFieldMapper(mapper, "field").fieldType().fieldType.storeTermVectors());
 
-        Stream.of(getShingleFieldMapper(mapper, "field._2gram"), getShingleFieldMapper(mapper, "field._3gram"))
-            .forEach(m -> assertTrue("for " + m.name(), m.fieldType.storeTermVectors()));
+            Stream.of(getShingleFieldMapper(mapper, "field._2gram"), getShingleFieldMapper(mapper, "field._3gram"))
+                .forEach(m -> assertTrue("for " + m.name(), m.fieldType.storeTermVectors()));
 
-        PrefixFieldMapper prefixFieldMapper = getPrefixFieldMapper(mapper, "field._index_prefix");
-        assertFalse(prefixFieldMapper.fieldType.storeTermVectors());
+            PrefixFieldMapper prefixFieldMapper = getPrefixFieldMapper(mapper, "field._index_prefix");
+            assertFalse(prefixFieldMapper.fieldType.storeTermVectors());
+            assertFalse(prefixFieldMapper.fieldType.storeTermVectorOffsets());
+            assertFalse(prefixFieldMapper.fieldType.storeTermVectorPositions());
+            assertFalse(prefixFieldMapper.fieldType.storeTermVectorPayloads());
+        }
     }
 
     public void testNorms() throws IOException {
@@ -594,7 +600,7 @@ public void testAnalyzerSerialization() throws IOException {
             b.field("type", "search_as_you_type");
             b.field("analyzer", "simple");
         }));
-        String serialized = Strings.toString(ms.documentMapper());
+        String serialized = Strings.toString(MediaTypeRegistry.JSON, ms.documentMapper());
         assertEquals(
             serialized,
             "{\"_doc\":{\"properties\":{\"field\":"
@@ -602,7 +608,7 @@ public void testAnalyzerSerialization() throws IOException {
         );
 
         merge(ms, mapping(b -> {}));
-        assertEquals(serialized, Strings.toString(ms.documentMapper()));
+        assertEquals(serialized, Strings.toString(MediaTypeRegistry.JSON, ms.documentMapper()));
     }
 
     private void documentParsingTestCase(Collection<String> values) throws IOException {
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldTypeTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldTypeTests.java
index 1998465318c2b..62b906d7442f6 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldTypeTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldTypeTests.java
@@ -49,10 +49,11 @@
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.List;
 
 import static java.util.Arrays.asList;
-import static org.apache.lucene.search.MultiTermQuery.CONSTANT_SCORE_REWRITE;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.lucene.search.MultiTermQuery.CONSTANT_SCORE_REWRITE;
 
 public class SearchAsYouTypeFieldTypeTests extends FieldTypeTestCase {
 
@@ -137,7 +138,10 @@ public void testPrefixQuery() {
 
         // this term should be too long to be rewriteable to a term query on the prefix field
         final String longTerm = "toolongforourprefixfieldthistermis";
-        assertThat(fieldType.prefixQuery(longTerm, CONSTANT_SCORE_REWRITE, MOCK_QSC), equalTo(new PrefixQuery(new Term(NAME, longTerm))));
+        assertThat(
+            fieldType.prefixQuery(longTerm, CONSTANT_SCORE_REWRITE, MOCK_QSC),
+            equalTo(new PrefixQuery(new Term(NAME, longTerm), CONSTANT_SCORE_REWRITE))
+        );
 
         OpenSearchException ee = expectThrows(
             OpenSearchException.class,
@@ -154,9 +158,9 @@ public void testFetchSourceValue() throws IOException {
         SearchAsYouTypeFieldType fieldType = createFieldType();
         fieldType.setIndexAnalyzer(Lucene.STANDARD_ANALYZER);
 
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(fieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(fieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(fieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(fieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(fieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(fieldType, true));
 
         SearchAsYouTypeFieldMapper.PrefixFieldType prefixFieldType = new SearchAsYouTypeFieldMapper.PrefixFieldType(
             fieldType.name(),
@@ -164,17 +168,17 @@ public void testFetchSourceValue() throws IOException {
             2,
             10
         );
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(prefixFieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(prefixFieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(prefixFieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(prefixFieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(prefixFieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(prefixFieldType, true));
 
         SearchAsYouTypeFieldMapper.ShingleFieldType shingleFieldType = new SearchAsYouTypeFieldMapper.ShingleFieldType(
             fieldType.name(),
             5,
             fieldType.getTextSearchInfo()
         );
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(shingleFieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(shingleFieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(shingleFieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(shingleFieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(shingleFieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(shingleFieldType, true));
     }
 }
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/TokenCountFieldMapperTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/TokenCountFieldMapperTests.java
index e9d3767373b95..a82128e5b190c 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/TokenCountFieldMapperTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/mapper/TokenCountFieldMapperTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.CannedTokenStream;
-import org.apache.lucene.tests.analysis.MockTokenizer;
-import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.core.KeywordAnalyzer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.apache.lucene.tests.analysis.CannedTokenStream;
+import org.apache.lucene.tests.analysis.MockTokenizer;
+import org.apache.lucene.tests.analysis.Token;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
diff --git a/modules/mapper-extras/src/test/java/org/opensearch/index/query/RankFeatureQueryBuilderTests.java b/modules/mapper-extras/src/test/java/org/opensearch/index/query/RankFeatureQueryBuilderTests.java
index e183ba6f6735c..015075d730984 100644
--- a/modules/mapper-extras/src/test/java/org/opensearch/index/query/RankFeatureQueryBuilderTests.java
+++ b/modules/mapper-extras/src/test/java/org/opensearch/index/query/RankFeatureQueryBuilderTests.java
@@ -36,7 +36,6 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.index.mapper.MapperExtrasPlugin;
 import org.opensearch.index.mapper.MapperService;
@@ -61,16 +60,14 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         mapperService.merge(
             "_doc",
             new CompressedXContent(
-                Strings.toString(
-                    PutMappingRequest.simpleMapping(
-                        "my_feature_field",
-                        "type=rank_feature",
-                        "my_negative_feature_field",
-                        "type=rank_feature,positive_score_impact=false",
-                        "my_feature_vector_field",
-                        "type=rank_features"
-                    )
-                )
+                PutMappingRequest.simpleMapping(
+                    "my_feature_field",
+                    "type=rank_feature",
+                    "my_negative_feature_field",
+                    "type=rank_feature,positive_score_impact=false",
+                    "my_feature_vector_field",
+                    "type=rank_features"
+                ).toString()
             ),
             MapperService.MergeReason.MAPPING_UPDATE
         );
diff --git a/modules/mapper-extras/src/test/resources/org/opensearch/index/mapper/metricbeat-6.0.template.json b/modules/mapper-extras/src/test/resources/org/opensearch/index/mapper/metricbeat-6.0.template.json
index f456755feeb93..5a83dbd2128c4 100644
--- a/modules/mapper-extras/src/test/resources/org/opensearch/index/mapper/metricbeat-6.0.template.json
+++ b/modules/mapper-extras/src/test/resources/org/opensearch/index/mapper/metricbeat-6.0.template.json
@@ -229,7 +229,7 @@
                 },
                 "objects": {
                   "properties": {
-                    "master": {
+                    "primary": {
                       "type": "long"
                     },
                     "total": {
@@ -4601,7 +4601,7 @@
                     "connected_replicas": {
                       "type": "long"
                     },
-                    "master_offset": {
+                    "primary_offset": {
                       "type": "long"
                     },
                     "role": {
diff --git a/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_feature/10_basic.yml b/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_feature/10_basic.yml
index 6fea35eb21f4e..ac951263ca299 100644
--- a/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_feature/10_basic.yml
+++ b/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_feature/10_basic.yml
@@ -157,3 +157,24 @@ setup:
 
   - match:
       hits.hits.1._id: "1"
+
+---
+"Negative linear":
+
+  - do:
+      search:
+        index: test
+        body:
+          query:
+            rank_feature:
+              field: url_length
+              linear: {}
+
+  - match:
+      hits.total.value: 2
+
+  - match:
+      hits.hits.0._id: "2"
+
+  - match:
+      hits.hits.1._id: "1"
diff --git a/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_features/10_basic.yml b/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_features/10_basic.yml
index d4d5d2a360406..2644b9e777f6a 100644
--- a/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_features/10_basic.yml
+++ b/modules/mapper-extras/src/yamlRestTest/resources/rest-api-spec/test/rank_features/10_basic.yml
@@ -9,6 +9,9 @@ setup:
               properties:
                 tags:
                    type: rank_features
+                negative_reviews:
+                   type: rank_features
+                   positive_score_impact: false
 
   - do:
       index:
@@ -18,6 +21,9 @@ setup:
           tags:
             foo: 3
             bar: 5
+          negative_reviews:
+            1star: 10
+            2star: 1
 
   - do:
       index:
@@ -27,6 +33,9 @@ setup:
           tags:
             bar: 6
             quux: 10
+          negative_reviews:
+            1star: 1
+            2star: 10
 
   - do:
       indices.refresh: {}
@@ -97,3 +106,34 @@ setup:
 
   - match:
       hits.hits.1._id: "1"
+
+---
+"Linear negative impact":
+
+  - do:
+      search:
+        index: test
+        body:
+          query:
+            rank_feature:
+              field: negative_reviews.1star
+              linear: {}
+
+  - match:
+      hits.hits.0._id: "2"
+  - match:
+      hits.hits.1._id: "1"
+
+  - do:
+      search:
+        index: test
+        body:
+          query:
+            rank_feature:
+              field: negative_reviews.2star
+              linear: {}
+
+  - match:
+      hits.hits.0._id: "1"
+  - match:
+      hits.hits.1._id: "2"
diff --git a/modules/opensearch-dashboards/build.gradle b/modules/opensearch-dashboards/build.gradle
index 9bda17243bdb4..f76ca739faf81 100644
--- a/modules/opensearch-dashboards/build.gradle
+++ b/modules/opensearch-dashboards/build.gradle
@@ -41,4 +41,3 @@ dependencies {
 testClusters.all {
   module ':modules:reindex'
 }
-
diff --git a/modules/opensearch-dashboards/src/javaRestTest/java/org/opensearch/dashboards/OpenSearchDashboardsSystemIndexIT.java b/modules/opensearch-dashboards/src/javaRestTest/java/org/opensearch/dashboards/OpenSearchDashboardsSystemIndexIT.java
index 2584a9b41f14d..0a9133ed5bca0 100644
--- a/modules/opensearch-dashboards/src/javaRestTest/java/org/opensearch/dashboards/OpenSearchDashboardsSystemIndexIT.java
+++ b/modules/opensearch-dashboards/src/javaRestTest/java/org/opensearch/dashboards/OpenSearchDashboardsSystemIndexIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.http.util.EntityUtils;
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/AbstractParentChildTestCase.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/AbstractParentChildTestCase.java
index 5566c688aefbf..e049edf843069 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/AbstractParentChildTestCase.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/AbstractParentChildTestCase.java
@@ -32,7 +32,14 @@
 
 package org.opensearch.join.aggregations;
 
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchRequestBuilder;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.client.Requests;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.join.query.ParentChildTestCase;
+import org.junit.Before;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -41,9 +48,8 @@
 import java.util.Map;
 import java.util.Set;
 
-import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.join.query.ParentChildTestCase;
-import org.junit.Before;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 
 /**
  * Small base test-class which combines stuff used for Children and Parent aggregation tests
@@ -52,6 +58,10 @@ public abstract class AbstractParentChildTestCase extends ParentChildTestCase {
     protected final Map<String, Control> categoryToControl = new HashMap<>();
     protected final Map<String, ParentControl> articleToControl = new HashMap<>();
 
+    public AbstractParentChildTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Before
     public void setupCluster() throws Exception {
         assertAcked(
@@ -154,4 +164,38 @@ private ParentControl(String category) {
             this.category = category;
         }
     }
+
+    // Test when there is 1 child document and 1 parent document per segment.
+    public void testSparseSegments() throws InterruptedException {
+        assertAcked(
+            prepareCreate("sparse").setMapping(
+                addFieldMappings(
+                    buildParentJoinFieldMappingFromSimplifiedDef("join_field", true, "article", "comment"),
+                    "commenter",
+                    "keyword",
+                    "category",
+                    "keyword"
+                )
+            )
+                .setSettings(
+                    Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                )
+        );
+
+        List<IndexRequestBuilder> requests = new ArrayList<>();
+        requests.add(createIndexRequest("sparse", "article", "article-0", null, "category", List.of("0")));
+        indexRandom(true, false, requests);
+        client().admin().indices().refresh(Requests.refreshRequest("sparse")).actionGet();
+        requests = new ArrayList<>();
+        requests.add(createIndexRequest("sparse", "comment", "comment-0", "article-0", "commenter", "0"));
+        indexRandom(true, false, requests);
+
+        SearchResponse searchResponse = getSearchRequest().get();
+        assertSearchResponse(searchResponse);
+        validateSpareSegmentsSearchResponse(searchResponse);
+    }
+
+    abstract SearchRequestBuilder getSearchRequest();
+
+    abstract void validateSpareSegmentsSearchResponse(SearchResponse searchResponse);
 }
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ChildrenIT.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ChildrenIT.java
index 08354cbaaf93b..5fc0a202ae45e 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ChildrenIT.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ChildrenIT.java
@@ -31,13 +31,17 @@
 
 package org.opensearch.join.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -47,14 +51,18 @@
 import org.opensearch.search.sort.SortOrder;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.join.aggregations.JoinAggregationBuilders.children;
 import static org.opensearch.join.query.JoinQueryBuilders.hasChildQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.search.aggregations.AggregationBuilders.topHits;
@@ -69,6 +77,23 @@
 
 public class ChildrenIT extends AbstractParentChildTestCase {
 
+    public ChildrenIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testChildrenAggs() throws Exception {
         SearchResponse searchResponse = client().prepareSearch("test")
             .setQuery(matchQuery("randomized", true))
@@ -227,7 +252,7 @@ public void testNonExistingChildType() throws Exception {
 
     public void testPostCollection() throws Exception {
         String indexName = "prodcatalog";
-        String masterType = "masterprod";
+        String mainType = "mainprod";
         String childType = "variantsku";
         assertAcked(
             prepareCreate(indexName).setSettings(
@@ -235,7 +260,7 @@ public void testPostCollection() throws Exception {
             )
                 .setMapping(
                     addFieldMappings(
-                        buildParentJoinFieldMappingFromSimplifiedDef("join_field", true, masterType, childType),
+                        buildParentJoinFieldMappingFromSimplifiedDef("join_field", true, mainType, childType),
                         "brand",
                         "text",
                         "name",
@@ -251,7 +276,7 @@ public void testPostCollection() throws Exception {
         );
 
         List<IndexRequestBuilder> requests = new ArrayList<>();
-        requests.add(createIndexRequest(indexName, masterType, "1", null, "brand", "Levis", "name", "Style 501", "material", "Denim"));
+        requests.add(createIndexRequest(indexName, mainType, "1", null, "brand", "Levis", "name", "Style 501", "material", "Denim"));
         requests.add(createIndexRequest(indexName, childType, "3", "1", "color", "blue", "size", "32"));
         requests.add(createIndexRequest(indexName, childType, "4", "1", "color", "blue", "size", "34"));
         requests.add(createIndexRequest(indexName, childType, "5", "1", "color", "blue", "size", "36"));
@@ -259,9 +284,7 @@ public void testPostCollection() throws Exception {
         requests.add(createIndexRequest(indexName, childType, "7", "1", "color", "black", "size", "40"));
         requests.add(createIndexRequest(indexName, childType, "8", "1", "color", "gray", "size", "36"));
 
-        requests.add(
-            createIndexRequest(indexName, masterType, "2", null, "brand", "Wrangler", "name", "Regular Cut", "material", "Leather")
-        );
+        requests.add(createIndexRequest(indexName, mainType, "2", null, "brand", "Wrangler", "name", "Regular Cut", "material", "Leather"));
         requests.add(createIndexRequest(indexName, childType, "9", "2", "color", "blue", "size", "32"));
         requests.add(createIndexRequest(indexName, childType, "10", "2", "color", "blue", "size", "34"));
         requests.add(createIndexRequest(indexName, childType, "12", "2", "color", "black", "size", "36"));
@@ -409,4 +432,18 @@ public void testPostCollectAllLeafReaders() throws Exception {
         children = parents.getBuckets().get(0).getAggregations().get("child_docs");
         assertThat(children.getDocCount(), equalTo(2L));
     }
+
+    @Override
+    SearchRequestBuilder getSearchRequest() {
+        return client().prepareSearch("sparse")
+            .setSize(10000)
+            .setQuery(matchAllQuery())
+            .addAggregation(children("to_comment", "comment").subAggregation(terms("commenters").field("commenter").size(10000)));
+    }
+
+    @Override
+    void validateSpareSegmentsSearchResponse(SearchResponse searchResponse) {
+        Children children = searchResponse.getAggregations().get("to_comment");
+        assertEquals(children.getDocCount(), 1);
+    }
 }
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ParentIT.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ParentIT.java
index 351b0beec481b..04703a65aa19d 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ParentIT.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/aggregations/ParentIT.java
@@ -32,12 +32,18 @@
 
 package org.opensearch.join.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -47,8 +53,10 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.join.aggregations.JoinAggregationBuilders.parent;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.search.aggregations.AggregationBuilders.topHits;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
@@ -56,6 +64,23 @@
 
 public class ParentIT extends AbstractParentChildTestCase {
 
+    public ParentIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testSimpleParentAgg() throws Exception {
         final SearchRequestBuilder searchRequest = client().prepareSearch("test")
             .setSize(10000)
@@ -264,4 +289,18 @@ public void testTermsParentAggTerms() throws Exception {
             }
         }
     }
+
+    @Override
+    SearchRequestBuilder getSearchRequest() {
+        return client().prepareSearch("sparse")
+            .setSize(10000)
+            .setQuery(matchAllQuery())
+            .addAggregation(parent("to_article", "comment").subAggregation(terms("category").field("category").size(10000)));
+    }
+
+    @Override
+    void validateSpareSegmentsSearchResponse(SearchResponse searchResponse) {
+        Parent parentAgg = searchResponse.getAggregations().get("to_article");
+        assertEquals(parentAgg.getDocCount(), 1);
+    }
 }
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ChildQuerySearchIT.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ChildQuerySearchIT.java
index d684f0bfebcfb..f7b8b47d2f3a2 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ChildQuerySearchIT.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ChildQuerySearchIT.java
@@ -31,6 +31,8 @@
 
 package org.opensearch.join.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.action.explain.ExplainResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -42,6 +44,8 @@
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
@@ -50,7 +54,6 @@
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
@@ -65,6 +68,8 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -87,6 +92,7 @@
 import static org.opensearch.join.query.JoinQueryBuilders.hasChildQuery;
 import static org.opensearch.join.query.JoinQueryBuilders.hasParentQuery;
 import static org.opensearch.join.query.JoinQueryBuilders.parentId;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -100,6 +106,23 @@
 
 public class ChildQuerySearchIT extends ParentChildTestCase {
 
+    public ChildQuerySearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testMultiLevelChild() throws Exception {
         assertAcked(
             prepareCreate("test").setMapping(
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/InnerHitsIT.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/InnerHitsIT.java
index ffcc9cf38545f..39da86c7fd726 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/InnerHitsIT.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/InnerHitsIT.java
@@ -32,11 +32,15 @@
 
 package org.opensearch.join.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
@@ -54,6 +58,7 @@
 import org.opensearch.search.sort.SortOrder;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -73,6 +78,7 @@
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 import static org.opensearch.join.query.JoinQueryBuilders.hasChildQuery;
 import static org.opensearch.join.query.JoinQueryBuilders.hasParentQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -87,6 +93,23 @@
 
 public class InnerHitsIT extends ParentChildTestCase {
 
+    public InnerHitsIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         ArrayList<Class<? extends Plugin>> plugins = new ArrayList<>(super.nodePlugins());
diff --git a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ParentChildTestCase.java b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ParentChildTestCase.java
index 5d6d4fb333d49..9b87b340eb0a8 100644
--- a/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ParentChildTestCase.java
+++ b/modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ParentChildTestCase.java
@@ -32,16 +32,16 @@
 package org.opensearch.join.query;
 
 import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexModule;
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -51,7 +51,11 @@
 import java.util.Map;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public abstract class ParentChildTestCase extends OpenSearchIntegTestCase {
+public abstract class ParentChildTestCase extends ParameterizedOpenSearchIntegTestCase {
+
+    public ParentChildTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
 
     @Override
     protected boolean ignoreExternalCluster() {
@@ -85,7 +89,7 @@ protected IndexRequestBuilder createIndexRequest(String index, String type, Stri
 
     protected IndexRequestBuilder createIndexRequest(String index, String type, String id, String parentId, XContentBuilder builder)
         throws IOException {
-        Map<String, Object> source = XContentHelper.convertToMap(JsonXContent.jsonXContent, Strings.toString(builder), false);
+        Map<String, Object> source = XContentHelper.convertToMap(JsonXContent.jsonXContent, builder.toString(), false);
         return createIndexRequest(index, type, id, parentId, source);
     }
 
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregationBuilder.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregationBuilder.java
index bff730878d1f3..b58e278133d95 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregationBuilder.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregationBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.join.aggregations;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.join.mapper.ParentIdFieldMapper;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregatorFactory.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregatorFactory.java
index 793b35111cfe2..bbca89fc56820 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregatorFactory.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenAggregatorFactory.java
@@ -118,4 +118,9 @@ public String getStatsSubtype() {
         // Child Aggregation is registered in non-standard way, so it might return child's values type
         return OTHER_SUBTYPE;
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenToParentAggregator.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenToParentAggregator.java
index d8fce3d72edb6..b6b1dff932be8 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenToParentAggregator.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ChildrenToParentAggregator.java
@@ -32,7 +32,7 @@
 package org.opensearch.join.aggregations;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalChildren.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalChildren.java
index d8221d2d2afb1..dfe34d16d016b 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalChildren.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalChildren.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalParent.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalParent.java
index d512d62526306..cd4522b3b063b 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalParent.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/InternalParent.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregationBuilder.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregationBuilder.java
index f180981db126e..7d0aaee71583e 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregationBuilder.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregationBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.join.aggregations;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.join.mapper.ParentIdFieldMapper;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregatorFactory.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregatorFactory.java
index 40c07c8f53e20..9a21cd1db3200 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregatorFactory.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentAggregatorFactory.java
@@ -118,4 +118,10 @@ public String getStatsSubtype() {
         // Parent Aggregation is registered in non-standard way
         return OTHER_SUBTYPE;
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        // See https://github.com/opensearch-project/OpenSearch/issues/9316
+        return false;
+    }
 }
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentToChildrenAggregator.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentToChildrenAggregator.java
index 8d342eada4d54..537034dbce4db 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentToChildrenAggregator.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParentToChildrenAggregator.java
@@ -32,7 +32,7 @@
 package org.opensearch.join.aggregations;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedChildren.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedChildren.java
index cbbf359943304..2704a30d45111 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedChildren.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedChildren.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedParent.java b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedParent.java
index 26c993403b667..f14ee81ad1b19 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedParent.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/aggregations/ParsedParent.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/mapper/ParentJoinFieldMapper.java b/modules/parent-join/src/main/java/org/opensearch/join/mapper/ParentJoinFieldMapper.java
index 662bacc0fb08a..a229d050f3b1d 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/mapper/ParentJoinFieldMapper.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/mapper/ParentJoinFieldMapper.java
@@ -38,9 +38,9 @@
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/query/HasChildQueryBuilder.java b/modules/parent-join/src/main/java/org/opensearch/join/query/HasChildQueryBuilder.java
index b25c1fd45e56e..1a51259e9e4e4 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/query/HasChildQueryBuilder.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/query/HasChildQueryBuilder.java
@@ -42,14 +42,14 @@
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.search.similarities.Similarity;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -416,11 +416,12 @@ public void visit(QueryVisitor visitor) {
         }
 
         @Override
-        public Query rewrite(IndexReader reader) throws IOException {
-            Query rewritten = super.rewrite(reader);
+        public Query rewrite(IndexSearcher searcher) throws IOException {
+            Query rewritten = super.rewrite(searcher);
             if (rewritten != this) {
                 return rewritten;
             }
+            IndexReader reader = searcher.getIndexReader();
             if (reader instanceof DirectoryReader) {
                 IndexSearcher indexSearcher = new IndexSearcher(reader);
                 indexSearcher.setQueryCache(null);
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/query/HasParentQueryBuilder.java b/modules/parent-join/src/main/java/org/opensearch/join/query/HasParentQueryBuilder.java
index 32cb8cf8174f0..d296a7b0141ff 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/query/HasParentQueryBuilder.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/query/HasParentQueryBuilder.java
@@ -35,13 +35,13 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.AbstractQueryBuilder;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/query/ParentIdQueryBuilder.java b/modules/parent-join/src/main/java/org/opensearch/join/query/ParentIdQueryBuilder.java
index 8964cdefc8eb2..bfc01bf151a9c 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/query/ParentIdQueryBuilder.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/query/ParentIdQueryBuilder.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
diff --git a/modules/parent-join/src/main/java/org/opensearch/join/spi/ParentJoinNamedXContentProvider.java b/modules/parent-join/src/main/java/org/opensearch/join/spi/ParentJoinNamedXContentProvider.java
index 2aee61dc8d6a4..95cd1e60f03cc 100644
--- a/modules/parent-join/src/main/java/org/opensearch/join/spi/ParentJoinNamedXContentProvider.java
+++ b/modules/parent-join/src/main/java/org/opensearch/join/spi/ParentJoinNamedXContentProvider.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.join.spi;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.join.aggregations.ChildrenAggregationBuilder;
 import org.opensearch.join.aggregations.ParentAggregationBuilder;
 import org.opensearch.join.aggregations.ParsedChildren;
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ChildrenToParentAggregatorTests.java b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ChildrenToParentAggregatorTests.java
index 0d134592fa678..21bdcd5f01fcc 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ChildrenToParentAggregatorTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ChildrenToParentAggregatorTests.java
@@ -38,19 +38,20 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.ContentPath;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
@@ -60,7 +61,6 @@
 import org.opensearch.index.mapper.MappingLookup;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.Uid;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.join.mapper.MetaJoinFieldMapper;
 import org.opensearch.join.mapper.ParentJoinFieldMapper;
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalChildrenTests.java b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalChildrenTests.java
index 8eaedc4aa15b0..2ad9afc75f285 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalChildrenTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalChildrenTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.NamedXContentRegistry.Entry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry.Entry;
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.Aggregation;
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalParentTests.java b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalParentTests.java
index cd5236ab49a39..26536ebd5c15b 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalParentTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/InternalParentTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.join.aggregations;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.NamedXContentRegistry.Entry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry.Entry;
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.Aggregation;
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentTests.java b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentTests.java
index abb258f37198b..20fde444e2a77 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.join.aggregations;
 
-import java.util.Arrays;
-import java.util.Collection;
-
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
 
+import java.util.Arrays;
+import java.util.Collection;
+
 public class ParentTests extends BaseAggregationTestCase<ParentAggregationBuilder> {
 
     @Override
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentToChildrenAggregatorTests.java b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentToChildrenAggregatorTests.java
index 2ed06ee0c0ea9..6b10389430fef 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentToChildrenAggregatorTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/aggregations/ParentToChildrenAggregatorTests.java
@@ -39,29 +39,29 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.ContentPath;
-import org.opensearch.index.mapper.MappingLookup;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.MappingLookup;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.Uid;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.join.ParentJoinPlugin;
 import org.opensearch.join.mapper.MetaJoinFieldMapper;
 import org.opensearch.join.mapper.ParentJoinFieldMapper;
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/mapper/ParentJoinFieldMapperTests.java b/modules/parent-join/src/test/java/org/opensearch/join/mapper/ParentJoinFieldMapperTests.java
index a9ac151dd3806..96e8287e8e75f 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/mapper/ParentJoinFieldMapperTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/mapper/ParentJoinFieldMapperTests.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.join.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperException;
@@ -60,19 +59,18 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testSingleLevel() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("join_field")
-                .field("type", "join")
-                .startObject("relations")
-                .field("parent", "child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService service = createIndex("test");
         DocumentMapper docMapper = service.mapperService()
             .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
@@ -80,7 +78,12 @@ public void testSingleLevel() throws Exception {
 
         // Doc without join
         ParsedDocument doc = docMapper.parse(
-            new SourceToParse("test", "0", BytesReference.bytes(XContentFactory.jsonBuilder().startObject().endObject()), XContentType.JSON)
+            new SourceToParse(
+                "test",
+                "0",
+                BytesReference.bytes(MediaTypeRegistry.JSON.contentBuilder().startObject().endObject()),
+                MediaTypeRegistry.JSON
+            )
         );
         assertNull(doc.rootDoc().getBinaryValue("join_field"));
 
@@ -90,7 +93,7 @@ public void testSingleLevel() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("join_field", "parent").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         assertEquals("1", doc.rootDoc().getBinaryValue("join_field#parent").utf8ToString());
@@ -110,7 +113,7 @@ public void testSingleLevel() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "1"
             )
         );
@@ -125,7 +128,7 @@ public void testSingleLevel() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("join_field", "unknown").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
         );
@@ -133,19 +136,18 @@ public void testSingleLevel() throws Exception {
     }
 
     public void testParentIdSpecifiedAsNumber() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("join_field")
-                .field("type", "join")
-                .startObject("relations")
-                .field("parent", "child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService service = createIndex("test");
         DocumentMapper docMapper = service.mapperService()
             .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
@@ -162,7 +164,7 @@ public void testParentIdSpecifiedAsNumber() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "1"
             )
         );
@@ -181,7 +183,7 @@ public void testParentIdSpecifiedAsNumber() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "1"
             )
         );
@@ -190,20 +192,19 @@ public void testParentIdSpecifiedAsNumber() throws Exception {
     }
 
     public void testMultipleLevels() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("join_field")
-                .field("type", "join")
-                .startObject("relations")
-                .field("parent", "child")
-                .field("child", "grand_child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .field("child", "grand_child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService service = createIndex("test");
         DocumentMapper docMapper = service.mapperService()
             .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
@@ -211,7 +212,12 @@ public void testMultipleLevels() throws Exception {
 
         // Doc without join
         ParsedDocument doc = docMapper.parse(
-            new SourceToParse("test", "0", BytesReference.bytes(XContentFactory.jsonBuilder().startObject().endObject()), XContentType.JSON)
+            new SourceToParse(
+                "test",
+                "0",
+                BytesReference.bytes(XContentFactory.jsonBuilder().startObject().endObject()),
+                MediaTypeRegistry.JSON
+            )
         );
         assertNull(doc.rootDoc().getBinaryValue("join_field"));
 
@@ -221,7 +227,7 @@ public void testMultipleLevels() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("join_field", "parent").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         assertEquals("1", doc.rootDoc().getBinaryValue("join_field#parent").utf8ToString());
@@ -241,7 +247,7 @@ public void testMultipleLevels() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "1"
             )
         );
@@ -257,7 +263,7 @@ public void testMultipleLevels() throws Exception {
                     "test",
                     "2",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("join_field", "child").endObject()),
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     "1"
                 )
             )
@@ -280,7 +286,7 @@ public void testMultipleLevels() throws Exception {
                             .endObject()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
         );
@@ -300,7 +306,7 @@ public void testMultipleLevels() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "1"
             )
         );
@@ -315,7 +321,7 @@ public void testMultipleLevels() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("join_field", "unknown").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
         );
@@ -323,39 +329,37 @@ public void testMultipleLevels() throws Exception {
     }
 
     public void testUpdateRelations() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .array("child", "grand_child1", "grand_child2")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+        IndexService indexService = createIndex("test");
+        DocumentMapper docMapper = indexService.mapperService()
+            .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        assertTrue(docMapper.mappers().getMapper("join_field") == ParentJoinFieldMapper.getMapper(indexService.mapperService()));
+
+        {
+            final String updateMapping = XContentFactory.jsonBuilder()
                 .startObject()
                 .startObject("properties")
                 .startObject("join_field")
                 .field("type", "join")
                 .startObject("relations")
-                .field("parent", "child")
                 .array("child", "grand_child1", "grand_child2")
                 .endObject()
                 .endObject()
                 .endObject()
                 .endObject()
-        );
-        IndexService indexService = createIndex("test");
-        DocumentMapper docMapper = indexService.mapperService()
-            .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
-        assertTrue(docMapper.mappers().getMapper("join_field") == ParentJoinFieldMapper.getMapper(indexService.mapperService()));
-
-        {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .array("child", "grand_child1", "grand_child2")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+                .toString();
             IllegalArgumentException exc = expectThrows(
                 IllegalArgumentException.class,
                 () -> indexService.mapperService()
@@ -365,20 +369,19 @@ public void testUpdateRelations() throws Exception {
         }
 
         {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("parent", "child")
-                    .field("child", "grand_child1")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .field("parent", "child")
+                .field("child", "grand_child1")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             IllegalArgumentException exc = expectThrows(
                 IllegalArgumentException.class,
                 () -> indexService.mapperService()
@@ -388,21 +391,20 @@ public void testUpdateRelations() throws Exception {
         }
 
         {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("uber_parent", "parent")
-                    .field("parent", "child")
-                    .array("child", "grand_child1", "grand_child2")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .field("uber_parent", "parent")
+                .field("parent", "child")
+                .array("child", "grand_child1", "grand_child2")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             IllegalArgumentException exc = expectThrows(
                 IllegalArgumentException.class,
                 () -> indexService.mapperService()
@@ -412,21 +414,20 @@ public void testUpdateRelations() throws Exception {
         }
 
         {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("parent", "child")
-                    .array("child", "grand_child1", "grand_child2")
-                    .field("grand_child2", "grand_grand_child")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .field("parent", "child")
+                .array("child", "grand_child1", "grand_child2")
+                .field("grand_child2", "grand_grand_child")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             IllegalArgumentException exc = expectThrows(
                 IllegalArgumentException.class,
                 () -> indexService.mapperService()
@@ -436,20 +437,19 @@ public void testUpdateRelations() throws Exception {
         }
 
         {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .array("parent", "child", "child2")
-                    .array("child", "grand_child1", "grand_child2")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .array("parent", "child", "child2")
+                .array("child", "grand_child1", "grand_child2")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             docMapper = indexService.mapperService()
                 .merge("type", new CompressedXContent(updateMapping), MapperService.MergeReason.MAPPING_UPDATE);
             ParentJoinFieldMapper mapper = ParentJoinFieldMapper.getMapper(indexService.mapperService());
@@ -462,21 +462,20 @@ public void testUpdateRelations() throws Exception {
         }
 
         {
-            final String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .array("parent", "child", "child2")
-                    .array("child", "grand_child1", "grand_child2")
-                    .array("other", "child_other1", "child_other2")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .array("parent", "child", "child2")
+                .array("child", "grand_child1", "grand_child2")
+                .array("other", "child_other1", "child_other2")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             docMapper = indexService.mapperService()
                 .merge("type", new CompressedXContent(updateMapping), MapperService.MergeReason.MAPPING_UPDATE);
             ParentJoinFieldMapper mapper = ParentJoinFieldMapper.getMapper(indexService.mapperService());
@@ -492,23 +491,22 @@ public void testUpdateRelations() throws Exception {
     }
 
     public void testInvalidJoinFieldInsideObject() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("join_field")
-                .field("type", "join")
-                .startObject("relations")
-                .field("parent", "child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService indexService = createIndex("test");
         MapperParsingException exc = expectThrows(
             MapperParsingException.class,
@@ -521,24 +519,23 @@ public void testInvalidJoinFieldInsideObject() throws Exception {
     }
 
     public void testInvalidJoinFieldInsideMultiFields() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("number")
-                .field("type", "integer")
-                .startObject("fields")
-                .startObject("join_field")
-                .field("type", "join")
-                .startObject("relations")
-                .field("parent", "child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("number")
+            .field("type", "integer")
+            .startObject("fields")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService indexService = createIndex("test");
         MapperParsingException exc = expectThrows(
             MapperParsingException.class,
@@ -553,26 +550,25 @@ public void testInvalidJoinFieldInsideMultiFields() throws Exception {
     public void testMultipleJoinFields() throws Exception {
         IndexService indexService = createIndex("test");
         {
-            String mapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("parent", "child")
-                    .field("child", "grand_child")
-                    .endObject()
-                    .endObject()
-                    .startObject("another_join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("product", "item")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            String mapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .field("parent", "child")
+                .field("child", "grand_child")
+                .endObject()
+                .endObject()
+                .startObject("another_join_field")
+                .field("type", "join")
+                .startObject("relations")
+                .field("product", "item")
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             MapperParsingException exc = expectThrows(
                 MapperParsingException.class,
                 () -> indexService.mapperService().merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE)
@@ -581,43 +577,7 @@ public void testMultipleJoinFields() throws Exception {
         }
 
         {
-            String mapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("join_field")
-                    .field("type", "join")
-                    .startObject("relations")
-                    .field("parent", "child")
-                    .field("child", "grand_child")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
-            indexService.mapperService().merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
-            String updateMapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("another_join_field")
-                    .field("type", "join")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
-            MapperParsingException exc = expectThrows(
-                MapperParsingException.class,
-                () -> indexService.mapperService()
-                    .merge("type", new CompressedXContent(updateMapping), MapperService.MergeReason.MAPPING_UPDATE)
-            );
-            assertThat(exc.getMessage(), containsString("Field [_parent_join] is defined more than once"));
-        }
-    }
-
-    public void testEagerGlobalOrdinals() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
+            String mapping = XContentFactory.jsonBuilder()
                 .startObject()
                 .startObject("properties")
                 .startObject("join_field")
@@ -629,7 +589,40 @@ public void testEagerGlobalOrdinals() throws Exception {
                 .endObject()
                 .endObject()
                 .endObject()
-        );
+                .toString();
+            indexService.mapperService().merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+            String updateMapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("another_join_field")
+                .field("type", "join")
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
+            MapperParsingException exc = expectThrows(
+                MapperParsingException.class,
+                () -> indexService.mapperService()
+                    .merge("type", new CompressedXContent(updateMapping), MapperService.MergeReason.MAPPING_UPDATE)
+            );
+            assertThat(exc.getMessage(), containsString("Field [_parent_join] is defined more than once"));
+        }
+    }
+
+    public void testEagerGlobalOrdinals() throws Exception {
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .startObject("relations")
+            .field("parent", "child")
+            .field("child", "grand_child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IndexService service = createIndex("test");
         DocumentMapper docMapper = service.mapperService()
             .merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
@@ -640,21 +633,20 @@ public void testEagerGlobalOrdinals() throws Exception {
         assertNotNull(service.mapperService().fieldType("join_field#child"));
         assertTrue(service.mapperService().fieldType("join_field#child").eagerGlobalOrdinals());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("join_field")
-                .field("type", "join")
-                .field("eager_global_ordinals", false)
-                .startObject("relations")
-                .field("parent", "child")
-                .field("child", "grand_child")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("join_field")
+            .field("type", "join")
+            .field("eager_global_ordinals", false)
+            .startObject("relations")
+            .field("parent", "child")
+            .field("child", "grand_child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         service.mapperService().merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
         assertFalse(service.mapperService().fieldType("join_field").eagerGlobalOrdinals());
         assertNotNull(service.mapperService().fieldType("join_field#parent"));
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/query/HasChildQueryBuilderTests.java b/modules/parent-join/src/test/java/org/opensearch/join/query/HasChildQueryBuilderTests.java
index 5595c98a439bf..096b87ec9e3f4 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/query/HasChildQueryBuilderTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/query/HasChildQueryBuilderTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.join.query;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
-import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermInSetQuery;
@@ -46,13 +46,10 @@
 import org.apache.lucene.search.similarities.Similarity;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.mapper.IdFieldMapper;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.InnerHitContextBuilder;
@@ -143,7 +140,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge(TYPE, new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge(TYPE, new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     /**
@@ -306,17 +303,9 @@ static void assertLateParsingQuery(Query query, String type, String id) throws I
         assertThat(booleanQuery.clauses().get(0).getOccur(), equalTo(BooleanClause.Occur.MUST));
         assertThat(booleanQuery.clauses().get(0).getQuery(), instanceOf(TermInSetQuery.class));
         TermInSetQuery termsQuery = (TermInSetQuery) booleanQuery.clauses().get(0).getQuery();
-        Query rewrittenTermsQuery = termsQuery.rewrite(null);
-        assertThat(rewrittenTermsQuery, instanceOf(ConstantScoreQuery.class));
-        ConstantScoreQuery constantScoreQuery = (ConstantScoreQuery) rewrittenTermsQuery;
-        assertThat(constantScoreQuery.getQuery(), instanceOf(BooleanQuery.class));
-        BooleanQuery booleanTermsQuery = (BooleanQuery) constantScoreQuery.getQuery();
-        assertThat(booleanTermsQuery.clauses().toString(), booleanTermsQuery.clauses().size(), equalTo(1));
-        assertThat(booleanTermsQuery.clauses().get(0).getOccur(), equalTo(BooleanClause.Occur.SHOULD));
-        assertThat(booleanTermsQuery.clauses().get(0).getQuery(), instanceOf(TermQuery.class));
-        TermQuery termQuery = (TermQuery) booleanTermsQuery.clauses().get(0).getQuery();
-        assertThat(termQuery.getTerm().field(), equalTo(IdFieldMapper.NAME));
-        assertThat(termQuery.getTerm().bytes(), equalTo(Uid.encodeId(id)));
+        // The query is of type MultiTermQueryConstantScoreBlendedWrapper and is sealed inside Apache Lucene,
+        // no access to inner queries without using the reflection, falling back to stringified query comparison
+        assertThat(termsQuery.toString(), equalTo("_id:([ff 69 64])"));
         // check the type filter
         assertThat(booleanQuery.clauses().get(1).getOccur(), equalTo(BooleanClause.Occur.FILTER));
         assertEquals(new TermQuery(new Term("join_field", type)), booleanQuery.clauses().get(1).getQuery());
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/query/HasParentQueryBuilderTests.java b/modules/parent-join/src/test/java/org/opensearch/join/query/HasParentQueryBuilderTests.java
index 0f983799a6d25..135f815b5441c 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/query/HasParentQueryBuilderTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/query/HasParentQueryBuilderTests.java
@@ -37,9 +37,8 @@
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
@@ -122,7 +121,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge(TYPE, new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge(TYPE, new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     /**
diff --git a/modules/parent-join/src/test/java/org/opensearch/join/query/ParentIdQueryBuilderTests.java b/modules/parent-join/src/test/java/org/opensearch/join/query/ParentIdQueryBuilderTests.java
index 41bc717db1fc8..558c94741b63d 100644
--- a/modules/parent-join/src/test/java/org/opensearch/join/query/ParentIdQueryBuilderTests.java
+++ b/modules/parent-join/src/test/java/org/opensearch/join/query/ParentIdQueryBuilderTests.java
@@ -39,9 +39,8 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
@@ -111,7 +110,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge(TYPE, new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge(TYPE, new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     @Override
diff --git a/modules/percolator/src/internalClusterTest/java/org/opensearch/percolator/PercolatorQuerySearchIT.java b/modules/percolator/src/internalClusterTest/java/org/opensearch/percolator/PercolatorQuerySearchIT.java
index 8d3c37bc9b039..516d8c8581de7 100644
--- a/modules/percolator/src/internalClusterTest/java/org/opensearch/percolator/PercolatorQuerySearchIT.java
+++ b/modules/percolator/src/internalClusterTest/java/org/opensearch/percolator/PercolatorQuerySearchIT.java
@@ -31,20 +31,24 @@
 
 package org.opensearch.percolator;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.geo.GeoPlugin;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.geo.GeoModulePlugin;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.query.MatchPhraseQueryBuilder;
 import org.opensearch.index.query.MultiMatchQueryBuilder;
@@ -53,7 +57,8 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
@@ -75,6 +80,7 @@
 import static org.opensearch.index.query.QueryBuilders.spanNotQuery;
 import static org.opensearch.index.query.QueryBuilders.spanTermQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchHits;
@@ -84,7 +90,24 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.core.IsNull.notNullValue;
 
-public class PercolatorQuerySearchIT extends OpenSearchIntegTestCase {
+public class PercolatorQuerySearchIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public PercolatorQuerySearchIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected boolean addMockGeoShapeFieldMapper() {
@@ -93,7 +116,7 @@ protected boolean addMockGeoShapeFieldMapper() {
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Arrays.asList(PercolatorPlugin.class, GeoPlugin.class);
+        return Arrays.asList(PercolatorPlugin.class, GeoModulePlugin.class);
     }
 
     public void testPercolatorQuery() throws Exception {
@@ -125,14 +148,16 @@ public void testPercolatorQuery() throws Exception {
 
         BytesReference source = BytesReference.bytes(jsonBuilder().startObject().endObject());
         logger.info("percolating empty doc");
-        SearchResponse response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        SearchResponse response = client().prepareSearch()
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
+            .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
 
         source = BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").endObject());
         logger.info("percolating doc with 1 field");
         response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
             .addSort("id", SortOrder.ASC)
             .get();
         assertHitCount(response, 2);
@@ -144,7 +169,7 @@ public void testPercolatorQuery() throws Exception {
         source = BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").field("field2", "value").endObject());
         logger.info("percolating doc with 2 fields");
         response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
             .addSort("id", SortOrder.ASC)
             .get();
         assertHitCount(response, 3);
@@ -164,7 +189,7 @@ public void testPercolatorQuery() throws Exception {
                         BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").endObject()),
                         BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").field("field2", "value").endObject())
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("id", SortOrder.ASC)
@@ -267,44 +292,46 @@ public void testPercolatorRangeQueries() throws Exception {
 
         // Test long range:
         BytesReference source = BytesReference.bytes(jsonBuilder().startObject().field("field1", 12).endObject());
-        SearchResponse response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        SearchResponse response = client().prepareSearch()
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
+            .get();
         logger.info("response={}", response);
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("3"));
         assertThat(response.getHits().getAt(1).getId(), equalTo("1"));
 
         source = BytesReference.bytes(jsonBuilder().startObject().field("field1", 11).endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
 
         // Test double range:
         source = BytesReference.bytes(jsonBuilder().startObject().field("field2", 12).endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("6"));
         assertThat(response.getHits().getAt(1).getId(), equalTo("4"));
 
         source = BytesReference.bytes(jsonBuilder().startObject().field("field2", 11).endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("4"));
 
         // Test IP range:
         source = BytesReference.bytes(jsonBuilder().startObject().field("field3", "192.168.1.5").endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("9"));
         assertThat(response.getHits().getAt(1).getId(), equalTo("7"));
 
         source = BytesReference.bytes(jsonBuilder().startObject().field("field3", "192.168.1.4").endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("7"));
 
         // Test date range:
         source = BytesReference.bytes(jsonBuilder().startObject().field("field4", "2016-05-15").endObject());
-        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+        response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("10"));
     }
@@ -355,7 +382,7 @@ public void testPercolatorGeoQueries() throws Exception {
             jsonBuilder().startObject().startObject("field1").field("lat", 52.20).field("lon", 4.51).endObject().endObject()
         );
         SearchResponse response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
             .addSort("id", SortOrder.ASC)
             .get();
         assertHitCount(response, 3);
@@ -390,9 +417,9 @@ public void testPercolatorQueryExistingDocument() throws Exception {
             )
             .get();
 
-        client().prepareIndex("test").setId("4").setSource("{\"id\": \"4\"}", XContentType.JSON).get();
-        client().prepareIndex("test").setId("5").setSource(XContentType.JSON, "id", "5", "field1", "value").get();
-        client().prepareIndex("test").setId("6").setSource(XContentType.JSON, "id", "6", "field1", "value", "field2", "value").get();
+        client().prepareIndex("test").setId("4").setSource("{\"id\": \"4\"}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex("test").setId("5").setSource(MediaTypeRegistry.JSON, "id", "5", "field1", "value").get();
+        client().prepareIndex("test").setId("6").setSource(MediaTypeRegistry.JSON, "id", "6", "field1", "value", "field2", "value").get();
         client().admin().indices().prepareRefresh().get();
 
         logger.info("percolating empty doc");
@@ -432,14 +459,13 @@ public void testPercolatorQueryExistingDocumentSourceDisabled() throws Exception
 
         client().prepareIndex("test").setId("1").setSource(jsonBuilder().startObject().field("query", matchAllQuery()).endObject()).get();
 
-        client().prepareIndex("test").setId("2").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("2").setSource("{}", MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         logger.info("percolating empty doc with source disabled");
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { client().prepareSearch().setQuery(new PercolateQueryBuilder("query", "test", "1", null, null, null)).get(); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            client().prepareSearch().setQuery(new PercolateQueryBuilder("query", "test", "1", null, null, null)).get();
+        });
         assertThat(e.getMessage(), containsString("source disabled"));
     }
 
@@ -529,7 +555,7 @@ public void testPercolatorSpecificQueries() throws Exception {
                 .endObject()
         );
         SearchResponse response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
             .addSort("id", SortOrder.ASC)
             .get();
         assertHitCount(response, 4);
@@ -587,7 +613,7 @@ public void testPercolatorQueryWithHighlighting() throws Exception {
             jsonBuilder().startObject().field("field1", "The quick brown fox jumps over the lazy dog").endObject()
         );
         SearchResponse searchResponse = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", document, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", document, MediaTypeRegistry.JSON))
             .highlighter(new HighlightBuilder().field("field1"))
             .addSort("id", SortOrder.ASC)
             .get();
@@ -620,8 +646,8 @@ public void testPercolatorQueryWithHighlighting() throws Exception {
         BytesReference document2 = BytesReference.bytes(jsonBuilder().startObject().field("field1", "over the lazy dog").endObject());
         searchResponse = client().prepareSearch()
             .setQuery(
-                boolQuery().should(new PercolateQueryBuilder("query", document1, XContentType.JSON).setName("query1"))
-                    .should(new PercolateQueryBuilder("query", document2, XContentType.JSON).setName("query2"))
+                boolQuery().should(new PercolateQueryBuilder("query", document1, MediaTypeRegistry.JSON).setName("query1"))
+                    .should(new PercolateQueryBuilder("query", document2, MediaTypeRegistry.JSON).setName("query2"))
             )
             .highlighter(new HighlightBuilder().field("field1"))
             .addSort("id", SortOrder.ASC)
@@ -660,7 +686,7 @@ public void testPercolatorQueryWithHighlighting() throws Exception {
                         BytesReference.bytes(jsonBuilder().startObject().field("field1", "jumps").endObject()),
                         BytesReference.bytes(jsonBuilder().startObject().field("field1", "brown fox").endObject())
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .highlighter(new HighlightBuilder().field("field1"))
@@ -713,7 +739,7 @@ public void testPercolatorQueryWithHighlighting() throws Exception {
                             BytesReference.bytes(jsonBuilder().startObject().field("field1", "dog").endObject()),
                             BytesReference.bytes(jsonBuilder().startObject().field("field1", "fox").endObject())
                         ),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     ).setName("query1")
                 )
                     .should(
@@ -723,7 +749,7 @@ public void testPercolatorQueryWithHighlighting() throws Exception {
                                 BytesReference.bytes(jsonBuilder().startObject().field("field1", "jumps").endObject()),
                                 BytesReference.bytes(jsonBuilder().startObject().field("field1", "brown fox").endObject())
                             ),
-                            XContentType.JSON
+                            MediaTypeRegistry.JSON
                         ).setName("query2")
                     )
             )
@@ -812,7 +838,7 @@ public void testTakePositionOffsetGapIntoAccount() throws Exception {
         client().admin().indices().prepareRefresh().get();
 
         SearchResponse response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("query", new BytesArray("{\"field\" : [\"brown\", \"fox\"]}"), XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("query", new BytesArray("{\"field\" : [\"brown\", \"fox\"]}"), MediaTypeRegistry.JSON))
             .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("2"));
@@ -900,7 +926,7 @@ public void testWithMultiplePercolatorFields() throws Exception {
 
         BytesReference source = BytesReference.bytes(jsonBuilder().startObject().field("field", "value").endObject());
         SearchResponse response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder(queryFieldName, source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder(queryFieldName, source, MediaTypeRegistry.JSON))
             .setIndices("test1")
             .get();
         assertHitCount(response, 1);
@@ -908,7 +934,7 @@ public void testWithMultiplePercolatorFields() throws Exception {
         assertThat(response.getHits().getAt(0).getIndex(), equalTo("test1"));
 
         response = client().prepareSearch()
-            .setQuery(new PercolateQueryBuilder("object_field." + queryFieldName, source, XContentType.JSON))
+            .setQuery(new PercolateQueryBuilder("object_field." + queryFieldName, source, MediaTypeRegistry.JSON))
             .setIndices("test2")
             .get();
         assertHitCount(response, 1);
@@ -1013,7 +1039,7 @@ public void testPercolateQueryWithNestedDocuments() throws Exception {
                             .endArray()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("id", SortOrder.ASC)
@@ -1040,7 +1066,7 @@ public void testPercolateQueryWithNestedDocuments() throws Exception {
                             .endArray()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("id", SortOrder.ASC)
@@ -1053,7 +1079,7 @@ public void testPercolateQueryWithNestedDocuments() throws Exception {
                 new PercolateQueryBuilder(
                     "query",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("companyname", "notstark").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("id", SortOrder.ASC)
@@ -1106,7 +1132,7 @@ public void testPercolateQueryWithNestedDocuments() throws Exception {
                                 .endObject()
                         )
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("id", SortOrder.ASC)
@@ -1159,7 +1185,7 @@ public void testPercolatorQueryViaMultiSearch() throws Exception {
                         new PercolateQueryBuilder(
                             "query",
                             BytesReference.bytes(jsonBuilder().startObject().field("field1", "b").endObject()),
-                            XContentType.JSON
+                            MediaTypeRegistry.JSON
                         )
                     )
             )
@@ -1179,7 +1205,7 @@ public void testPercolatorQueryViaMultiSearch() throws Exception {
                         new PercolateQueryBuilder(
                             "query",
                             BytesReference.bytes(jsonBuilder().startObject().field("field1", "b c").endObject()),
-                            XContentType.JSON
+                            MediaTypeRegistry.JSON
                         )
                     )
             )
@@ -1189,7 +1215,7 @@ public void testPercolatorQueryViaMultiSearch() throws Exception {
                         new PercolateQueryBuilder(
                             "query",
                             BytesReference.bytes(jsonBuilder().startObject().field("field1", "d").endObject()),
-                            XContentType.JSON
+                            MediaTypeRegistry.JSON
                         )
                     )
             )
@@ -1249,7 +1275,7 @@ public void testDisallowExpensiveQueries() throws IOException {
             // Execute with search.allow_expensive_queries = null => default value = false => success
             BytesReference source = BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").endObject());
             SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON))
+                .setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON))
                 .get();
             assertHitCount(response, 1);
             assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
@@ -1262,7 +1288,7 @@ public void testDisallowExpensiveQueries() throws IOException {
 
             OpenSearchException e = expectThrows(
                 OpenSearchException.class,
-                () -> client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get()
+                () -> client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get()
             );
             assertEquals(
                 "[percolate] queries cannot be executed when 'search.allow_expensive_queries' is set to false.",
@@ -1274,7 +1300,7 @@ public void testDisallowExpensiveQueries() throws IOException {
             updateSettingsRequest.persistentSettings(Settings.builder().put("search.allow_expensive_queries", true));
             assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
 
-            response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, XContentType.JSON)).get();
+            response = client().prepareSearch().setQuery(new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON)).get();
             assertHitCount(response, 1);
             assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
             assertThat(response.getHits().getAt(0).getFields().get("_percolator_document_slot").getValue(), equalTo(0));
@@ -1308,7 +1334,7 @@ public void testWrappedWithConstantScore() throws Exception {
                 new PercolateQueryBuilder(
                     "q",
                     BytesReference.bytes(jsonBuilder().startObject().field("d", "2020-02-01T15:00:00.000+11:00").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .get();
@@ -1319,7 +1345,7 @@ public void testWrappedWithConstantScore() throws Exception {
                 new PercolateQueryBuilder(
                     "q",
                     BytesReference.bytes(jsonBuilder().startObject().field("d", "2020-02-01T15:00:00.000+11:00").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .addSort("_doc", SortOrder.ASC)
@@ -1332,7 +1358,7 @@ public void testWrappedWithConstantScore() throws Exception {
                     new PercolateQueryBuilder(
                         "q",
                         BytesReference.bytes(jsonBuilder().startObject().field("d", "2020-02-01T15:00:00.000+11:00").endObject()),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 )
             )
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQuery.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQuery.java
index 0aa8318e7c191..99907b48d4fdd 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQuery.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQuery.java
@@ -32,8 +32,9 @@
 
 package org.opensearch.percolator;
 
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.BooleanClause.Occur;
+import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.IndexSearcher;
@@ -45,13 +46,11 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TwoPhaseIterator;
 import org.apache.lucene.search.Weight;
-import org.apache.lucene.search.BooleanClause.Occur;
-import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.Bits;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.util.List;
@@ -89,8 +88,8 @@ final class PercolateQuery extends Query implements Accountable {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query rewritten = candidateMatchesQuery.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query rewritten = candidateMatchesQuery.rewrite(searcher);
         if (rewritten != candidateMatchesQuery) {
             return new PercolateQuery(
                 name,
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
index b2130eca3bb02..6933bfbef4666 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
@@ -54,27 +54,31 @@
 import org.apache.lucene.util.BitDocIdSet;
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.FieldNameAnalyzer;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
@@ -90,8 +94,6 @@
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.index.query.Rewriteable;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
@@ -103,8 +105,8 @@
 import java.util.Objects;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
 public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBuilder> {
@@ -123,7 +125,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
     private final String field;
     private String name;
     private final List<BytesReference> documents;
-    private final XContentType documentXContentType;
+    private final MediaType documentXContentType;
 
     private final String indexedDocumentIndex;
     private final String indexedDocumentId;
@@ -137,10 +139,10 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
      *
      * @param field                     The field that contains the percolator query
      * @param document                  The binary blob containing document to percolate
-     * @param documentXContentType      The content type of the binary blob containing the document to percolate
+     * @param documentMediaType      The content type of the binary blob containing the document to percolate
      */
-    public PercolateQueryBuilder(String field, BytesReference document, XContentType documentXContentType) {
-        this(field, Collections.singletonList(document), documentXContentType);
+    public PercolateQueryBuilder(String field, BytesReference document, MediaType documentMediaType) {
+        this(field, Collections.singletonList(document), documentMediaType);
     }
 
     /**
@@ -150,7 +152,7 @@ public PercolateQueryBuilder(String field, BytesReference document, XContentType
      * @param documents                  The binary blob containing document to percolate
      * @param documentXContentType      The content type of the binary blob containing the document to percolate
      */
-    public PercolateQueryBuilder(String field, List<BytesReference> documents, XContentType documentXContentType) {
+    public PercolateQueryBuilder(String field, List<BytesReference> documents, MediaType documentXContentType) {
         if (field == null) {
             throw new IllegalArgumentException("[field] is a required argument");
         }
@@ -252,7 +254,11 @@ protected PercolateQueryBuilder(String field, Supplier<BytesReference> documentS
         }
         documents = in.readList(StreamInput::readBytesReference);
         if (documents.isEmpty() == false) {
-            documentXContentType = in.readEnum(XContentType.class);
+            if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                documentXContentType = in.readMediaType();
+            } else {
+                documentXContentType = in.readEnum(XContentType.class);
+            }
         } else {
             documentXContentType = null;
         }
@@ -298,7 +304,11 @@ protected void doWriteTo(StreamOutput out) throws IOException {
             out.writeBytesReference(document);
         }
         if (documents.isEmpty() == false) {
-            out.writeEnum(documentXContentType);
+            if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                documentXContentType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) documentXContentType);
+            }
         }
     }
 
@@ -359,9 +369,9 @@ protected void doXContent(XContentBuilder builder, Params params) throws IOExcep
         if (indexedDocId != null) {
             return new PercolateQueryBuilder(field, indexedDocIndex, indexedDocId, indexDocRouting, indexDocPreference, indexedDocVersion);
         } else if (document != null) {
-            return new PercolateQueryBuilder(field, Collections.singletonList(document), XContentType.JSON);
+            return new PercolateQueryBuilder(field, Collections.singletonList(document), MediaTypeRegistry.JSON);
         } else {
-            return new PercolateQueryBuilder(field, documents, XContentType.JSON);
+            return new PercolateQueryBuilder(field, documents, MediaTypeRegistry.JSON);
         }
     });
     static {
@@ -432,7 +442,7 @@ protected QueryBuilder doRewrite(QueryRewriteContext queryShardContext) {
                 PercolateQueryBuilder rewritten = new PercolateQueryBuilder(
                     field,
                     Collections.singletonList(source),
-                    XContentHelper.xContentType(source)
+                    MediaTypeRegistry.xContentType(source)
                 );
                 if (name != null) {
                     rewritten.setName(name);
@@ -546,7 +556,6 @@ protected Analyzer getWrappedAnalyzer(String fieldName) {
         String name = this.name != null ? this.name : pft.name();
         QueryShardContext percolateShardContext = wrap(context);
         PercolatorFieldMapper.configureContext(percolateShardContext, pft.mapUnmappedFieldsAsText);
-        ;
         PercolateQuery.QueryStore queryStore = createStore(pft.queryBuilderField, percolateShardContext);
 
         return pft.percolateQuery(name, queryStore, documents, docSearcher, excludeNestedDocuments, context.indexVersionCreated());
@@ -561,7 +570,7 @@ public List<BytesReference> getDocuments() {
     }
 
     // pkg-private for testing
-    XContentType getXContentType() {
+    MediaType getXContentType() {
         return documentXContentType;
     }
 
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorFieldMapper.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorFieldMapper.java
index fec38207582e7..e30ce218ed5ff 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorFieldMapper.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorFieldMapper.java
@@ -56,16 +56,16 @@
 import org.apache.lucene.util.BytesRefBuilder;
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.hash.MurmurHash3;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.FieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhase.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhase.java
index 9b4e42d239750..78e5980e88d5c 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhase.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhase.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.fetch.FetchContext;
 import org.opensearch.search.fetch.FetchSubPhase;
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhase.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhase.java
index a157a20f5f2c4..0884d534849da 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhase.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhase.java
@@ -57,8 +57,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
-import static org.apache.lucene.search.DocIdSetIterator.NO_MORE_DOCS;
 import static org.opensearch.percolator.PercolatorHighlightSubFetchPhase.locatePercolatorQuery;
+import static org.apache.lucene.search.DocIdSetIterator.NO_MORE_DOCS;
 
 /**
  * Adds a special field to a percolator query hit to indicate which documents matched with the percolator query.
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/CandidateQueryTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/CandidateQueryTests.java
index e59aa227e3dc7..64c0c01be6314 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/CandidateQueryTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/CandidateQueryTests.java
@@ -94,14 +94,13 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.geo.ShapeRelation;
+import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DocumentMapper;
@@ -112,9 +111,9 @@
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
+import org.opensearch.test.VersionUtils;
 import org.junit.After;
 import org.junit.Before;
-import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -163,51 +162,49 @@ public void init() throws Exception {
         indexService = createIndex(indexName, Settings.EMPTY);
         mapperService = indexService.mapperService();
 
-        String mapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("int_field")
-                .field("type", "integer")
-                .endObject()
-                .startObject("long_field")
-                .field("type", "long")
-                .endObject()
-                .startObject("half_float_field")
-                .field("type", "half_float")
-                .endObject()
-                .startObject("float_field")
-                .field("type", "float")
-                .endObject()
-                .startObject("double_field")
-                .field("type", "double")
-                .endObject()
-                .startObject("ip_field")
-                .field("type", "ip")
-                .endObject()
-                .startObject("field")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("int_field")
+            .field("type", "integer")
+            .endObject()
+            .startObject("long_field")
+            .field("type", "long")
+            .endObject()
+            .startObject("half_float_field")
+            .field("type", "half_float")
+            .endObject()
+            .startObject("float_field")
+            .field("type", "float")
+            .endObject()
+            .startObject("double_field")
+            .field("type", "double")
+            .endObject()
+            .startObject("ip_field")
+            .field("type", "ip")
+            .endObject()
+            .startObject("field")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         documentMapper = mapperService.merge("type", new CompressedXContent(mapper), MapperService.MergeReason.MAPPING_UPDATE);
 
         String queryField = "query_field";
-        String percolatorMapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject(queryField)
-                .field("type", "percolator")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String percolatorMapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject(queryField)
+            .field("type", "percolator")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge("type", new CompressedXContent(percolatorMapper), MapperService.MergeReason.MAPPING_UPDATE);
         fieldMapper = (PercolatorFieldMapper) mapperService.documentMapper().mappers().getMapper(queryField);
         fieldType = (PercolatorFieldMapper.PercolatorFieldType) fieldMapper.fieldType();
@@ -1275,7 +1272,7 @@ private CustomQuery(Term term) {
         }
 
         @Override
-        public Query rewrite(IndexReader reader) throws IOException {
+        public Query rewrite(IndexSearcher searcher) throws IOException {
             return new TermQuery(term);
         }
 
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryBuilderTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryBuilderTests.java
index 87aa28a3346bc..9891ec8527267 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryBuilderTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryBuilderTests.java
@@ -38,15 +38,14 @@
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryBuilder;
@@ -109,15 +108,13 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         mapperService.merge(
             docType,
             new CompressedXContent(
-                Strings.toString(
-                    PutMappingRequest.simpleMapping(queryField, "type=percolator", aliasField, "type=alias,path=" + queryField)
-                )
+                PutMappingRequest.simpleMapping(queryField, "type=percolator", aliasField, "type=alias,path=" + queryField).toString()
             ),
             MapperService.MergeReason.MAPPING_UPDATE
         );
         mapperService.merge(
             docType,
-            new CompressedXContent(Strings.toString(PutMappingRequest.simpleMapping(TEXT_FIELD_NAME, "type=text"))),
+            new CompressedXContent(PutMappingRequest.simpleMapping(TEXT_FIELD_NAME, "type=text").toString()),
             MapperService.MergeReason.MAPPING_UPDATE
         );
     }
@@ -155,7 +152,7 @@ private PercolateQueryBuilder doCreateTestQueryBuilder(boolean indexedDocument)
                 indexedDocumentVersion
             );
         } else {
-            queryBuilder = new PercolateQueryBuilder(queryField, documentSource, XContentType.JSON);
+            queryBuilder = new PercolateQueryBuilder(queryField, documentSource, MediaTypeRegistry.JSON);
         }
         if (randomBoolean()) {
             queryBuilder.setName(randomAlphaOfLength(4));
@@ -224,7 +221,7 @@ public void testMustRewrite() throws IOException {
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> pqb.toQuery(createShardContext()));
         assertThat(e.getMessage(), equalTo("query builder must be rewritten first"));
         QueryBuilder rewrite = rewriteAndFetch(pqb, createShardContext());
-        PercolateQueryBuilder geoShapeQueryBuilder = new PercolateQueryBuilder(pqb.getField(), documentSource, XContentType.JSON);
+        PercolateQueryBuilder geoShapeQueryBuilder = new PercolateQueryBuilder(pqb.getField(), documentSource, MediaTypeRegistry.JSON);
         assertEquals(geoShapeQueryBuilder, rewrite);
     }
 
@@ -245,15 +242,14 @@ protected Set<String> getObjectsHoldingArbitraryContent() {
     }
 
     public void testRequiredParameters() {
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { new PercolateQueryBuilder(null, new BytesArray("{}"), XContentType.JSON); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            new PercolateQueryBuilder(null, new BytesArray("{}"), MediaTypeRegistry.JSON);
+        });
         assertThat(e.getMessage(), equalTo("[field] is a required argument"));
 
         e = expectThrows(
             IllegalArgumentException.class,
-            () -> new PercolateQueryBuilder("_field", (List<BytesReference>) null, XContentType.JSON)
+            () -> new PercolateQueryBuilder("_field", (List<BytesReference>) null, MediaTypeRegistry.JSON)
         );
         assertThat(e.getMessage(), equalTo("[document] is a required argument"));
 
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryTests.java
index c5049e21acc0c..f75367fc054c0 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateQueryTests.java
@@ -56,7 +56,7 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateWithNestedQueryBuilderTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateWithNestedQueryBuilderTests.java
index 0ab9eff731bff..a5682928863cc 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolateWithNestedQueryBuilderTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolateWithNestedQueryBuilderTests.java
@@ -33,10 +33,9 @@
 package org.opensearch.percolator;
 
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
@@ -50,7 +49,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         super.initializeAdditionalMappings(mapperService);
         mapperService.merge(
             "_doc",
-            new CompressedXContent(Strings.toString(PutMappingRequest.simpleMapping("some_nested_object", "type=nested"))),
+            new CompressedXContent(PutMappingRequest.simpleMapping("some_nested_object", "type=nested").toString()),
             MapperService.MergeReason.MAPPING_UPDATE
         );
     }
@@ -58,7 +57,11 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
     public void testDetectsNestedDocuments() throws IOException {
         QueryShardContext shardContext = createShardContext();
 
-        PercolateQueryBuilder builder = new PercolateQueryBuilder(queryField, new BytesArray("{ \"foo\": \"bar\" }"), XContentType.JSON);
+        PercolateQueryBuilder builder = new PercolateQueryBuilder(
+            queryField,
+            new BytesArray("{ \"foo\": \"bar\" }"),
+            MediaTypeRegistry.JSON
+        );
         QueryBuilder rewrittenBuilder = rewriteAndFetch(builder, shardContext);
         PercolateQuery query = (PercolateQuery) rewrittenBuilder.toQuery(shardContext);
         assertFalse(query.excludesNestedDocs());
@@ -66,7 +69,7 @@ public void testDetectsNestedDocuments() throws IOException {
         builder = new PercolateQueryBuilder(
             queryField,
             new BytesArray("{ \"foo\": \"bar\", \"some_nested_object\": [ { \"baz\": 42 } ] }"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         rewrittenBuilder = rewriteAndFetch(builder, shardContext);
         query = (PercolateQuery) rewrittenBuilder.toQuery(shardContext);
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorFieldMapperTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorFieldMapperTests.java
index ca6f3a78b27d7..95da3c54ec61e 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorFieldMapperTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorFieldMapperTests.java
@@ -56,21 +56,20 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.hash.MurmurHash3;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DocumentMapper;
@@ -101,8 +100,8 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.junit.Before;
 
 import java.io.ByteArrayInputStream;
@@ -158,67 +157,65 @@ public void init() throws Exception {
         indexService = createIndex("test");
         mapperService = indexService.mapperService();
 
-        String mapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "text")
-                .endObject()
-                .startObject("field1")
-                .field("type", "text")
-                .endObject()
-                .startObject("field2")
-                .field("type", "text")
-                .endObject()
-                .startObject("_field3")
-                .field("type", "text")
-                .endObject()
-                .startObject("field4")
-                .field("type", "text")
-                .endObject()
-                .startObject("number_field1")
-                .field("type", "integer")
-                .endObject()
-                .startObject("number_field2")
-                .field("type", "long")
-                .endObject()
-                .startObject("number_field3")
-                .field("type", "long")
-                .endObject()
-                .startObject("number_field4")
-                .field("type", "half_float")
-                .endObject()
-                .startObject("number_field5")
-                .field("type", "float")
-                .endObject()
-                .startObject("number_field6")
-                .field("type", "double")
-                .endObject()
-                .startObject("number_field7")
-                .field("type", "ip")
-                .endObject()
-                .startObject("date_field")
-                .field("type", "date")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .endObject()
+            .startObject("field1")
+            .field("type", "text")
+            .endObject()
+            .startObject("field2")
+            .field("type", "text")
+            .endObject()
+            .startObject("_field3")
+            .field("type", "text")
+            .endObject()
+            .startObject("field4")
+            .field("type", "text")
+            .endObject()
+            .startObject("number_field1")
+            .field("type", "integer")
+            .endObject()
+            .startObject("number_field2")
+            .field("type", "long")
+            .endObject()
+            .startObject("number_field3")
+            .field("type", "long")
+            .endObject()
+            .startObject("number_field4")
+            .field("type", "half_float")
+            .endObject()
+            .startObject("number_field5")
+            .field("type", "float")
+            .endObject()
+            .startObject("number_field6")
+            .field("type", "double")
+            .endObject()
+            .startObject("number_field7")
+            .field("type", "ip")
+            .endObject()
+            .startObject("date_field")
+            .field("type", "date")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapper), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     private void addQueryFieldMappings() throws Exception {
         fieldName = randomAlphaOfLength(4);
-        String percolatorMapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject(fieldName)
-                .field("type", "percolator")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String percolatorMapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject(fieldName)
+            .field("type", "percolator")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(
             MapperService.SINGLE_MAPPING_NAME,
             new CompressedXContent(percolatorMapper),
@@ -555,7 +552,7 @@ public void testPercolatorFieldMapper() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, queryBuilder).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
 
@@ -575,7 +572,7 @@ public void testPercolatorFieldMapper() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, queryBuilder).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields(fieldType.extractionResultField.name()).length, equalTo(1));
@@ -592,7 +589,7 @@ public void testPercolatorFieldMapper() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, queryBuilder).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields(fieldType.extractionResultField.name()).length, equalTo(1));
@@ -620,7 +617,7 @@ public void testStoringQueries() throws Exception {
                         "test",
                         "1",
                         BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, query).endObject()),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 );
             BytesRef qbSource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
@@ -638,7 +635,7 @@ public void testQueryWithRewrite() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, queryBuilder).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         BytesRef qbSource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
@@ -664,7 +661,7 @@ public void testPercolatorFieldMapperUnMappedField() throws Exception {
                         BytesReference.bytes(
                             XContentFactory.jsonBuilder().startObject().field(fieldName, termQuery("unmapped_field", "value")).endObject()
                         ),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 );
         });
@@ -680,7 +677,7 @@ public void testPercolatorFieldMapper_noQuery() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields(fieldType.queryBuilderField.name()).length, equalTo(0));
@@ -692,7 +689,7 @@ public void testPercolatorFieldMapper_noQuery() throws Exception {
                         "test",
                         "1",
                         BytesReference.bytes(XContentFactory.jsonBuilder().startObject().nullField(fieldName).endObject()),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 );
         } catch (MapperParsingException e) {
@@ -705,17 +702,16 @@ public void testAllowNoAdditionalSettings() throws Exception {
         IndexService indexService = createIndex("test1", Settings.EMPTY);
         MapperService mapperService = indexService.mapperService();
 
-        String percolatorMapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject(fieldName)
-                .field("type", "percolator")
-                .field("index", "no")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String percolatorMapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject(fieldName)
+            .field("type", "percolator")
+            .field("index", "no")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MapperParsingException e = expectThrows(
             MapperParsingException.class,
             () -> mapperService.merge(
@@ -730,21 +726,20 @@ public void testAllowNoAdditionalSettings() throws Exception {
     // multiple percolator fields are allowed in the mapping, but only one field can be used at index time.
     public void testMultiplePercolatorFields() throws Exception {
         String typeName = MapperService.SINGLE_MAPPING_NAME;
-        String percolatorMapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(typeName)
-                .startObject("properties")
-                .startObject("query_field1")
-                .field("type", "percolator")
-                .endObject()
-                .startObject("query_field2")
-                .field("type", "percolator")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String percolatorMapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(typeName)
+            .startObject("properties")
+            .startObject("query_field1")
+            .field("type", "percolator")
+            .endObject()
+            .startObject("query_field2")
+            .field("type", "percolator")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(typeName, new CompressedXContent(percolatorMapper), MapperService.MergeReason.MAPPING_UPDATE);
 
         QueryBuilder queryBuilder = matchQuery("field", "value");
@@ -756,7 +751,7 @@ public void testMultiplePercolatorFields() throws Exception {
                     BytesReference.bytes(
                         jsonBuilder().startObject().field("query_field1", queryBuilder).field("query_field2", queryBuilder).endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields().size(), equalTo(16)); // also includes all other meta fields
@@ -770,23 +765,22 @@ public void testMultiplePercolatorFields() throws Exception {
     // percolator field can be nested under an object field, but only one query can be specified per document
     public void testNestedPercolatorField() throws Exception {
         String typeName = MapperService.SINGLE_MAPPING_NAME;
-        String percolatorMapper = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(typeName)
-                .startObject("properties")
-                .startObject("object_field")
-                .field("type", "object")
-                .startObject("properties")
-                .startObject("query_field")
-                .field("type", "percolator")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String percolatorMapper = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(typeName)
+            .startObject("properties")
+            .startObject("object_field")
+            .field("type", "object")
+            .startObject("properties")
+            .startObject("query_field")
+            .field("type", "percolator")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(typeName, new CompressedXContent(percolatorMapper), MapperService.MergeReason.MAPPING_UPDATE);
 
         QueryBuilder queryBuilder = matchQuery("field", "value");
@@ -798,7 +792,7 @@ public void testNestedPercolatorField() throws Exception {
                     BytesReference.bytes(
                         jsonBuilder().startObject().startObject("object_field").field("query_field", queryBuilder).endObject().endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields().size(), equalTo(12)); // also includes all other meta fields
@@ -823,7 +817,7 @@ public void testNestedPercolatorField() throws Exception {
                             .endArray()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         assertThat(doc.rootDoc().getFields().size(), equalTo(12)); // also includes all other meta fields
@@ -848,7 +842,7 @@ public void testNestedPercolatorField() throws Exception {
                                 .endArray()
                                 .endObject()
                         ),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 );
         });
@@ -862,7 +856,7 @@ public void testUnsupportedQueries() {
         PercolatorFieldMapper.verifyQuery(rangeQuery1);
         PercolatorFieldMapper.verifyQuery(rangeQuery2);
 
-        HasChildQueryBuilder hasChildQuery = new HasChildQueryBuilder("_type", new MatchAllQueryBuilder(), ScoreMode.None);
+        HasChildQueryBuilder hasChildQuery = new HasChildQueryBuilder("parent", new MatchAllQueryBuilder(), ScoreMode.None);
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(new BoolQueryBuilder().must(hasChildQuery)));
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(new DisMaxQueryBuilder().add(hasChildQuery)));
         PercolatorFieldMapper.verifyQuery(new ConstantScoreQueryBuilder((rangeQuery1)));
@@ -881,7 +875,7 @@ public void testUnsupportedQueries() {
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(hasChildQuery));
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(new BoolQueryBuilder().must(hasChildQuery)));
 
-        HasParentQueryBuilder hasParentQuery = new HasParentQueryBuilder("_type", new MatchAllQueryBuilder(), false);
+        HasParentQueryBuilder hasParentQuery = new HasParentQueryBuilder("parent", new MatchAllQueryBuilder(), false);
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(hasParentQuery));
         expectThrows(IllegalArgumentException.class, () -> PercolatorFieldMapper.verifyQuery(new BoolQueryBuilder().must(hasParentQuery)));
     }
@@ -902,18 +896,17 @@ private void assertQueryBuilder(BytesRef actual, QueryBuilder expected) throws I
     }
 
     public void testEmptyName() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type1")
-                .startObject("properties")
-                .startObject("")
-                .field("type", "percolator")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type1")
+            .startObject("properties")
+            .startObject("")
+            .field("type", "percolator")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapperParser parser = mapperService.documentMapperParser();
 
         IllegalArgumentException e = expectThrows(
@@ -946,10 +939,10 @@ public void testImplicitlySetDefaultScriptLang() throws Exception {
                     BytesReference.bytes(
                         XContentFactory.jsonBuilder()
                             .startObject()
-                            .rawField(fieldName, new BytesArray(Strings.toString(query)).streamInput(), query.contentType())
+                            .rawField(fieldName, new BytesArray(query.toString()).streamInput(), query.contentType())
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         BytesRef querySource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
@@ -993,10 +986,10 @@ public void testImplicitlySetDefaultScriptLang() throws Exception {
                     BytesReference.bytes(
                         XContentFactory.jsonBuilder()
                             .startObject()
-                            .rawField(fieldName, new BytesArray(Strings.toString(query)).streamInput(), query.contentType())
+                            .rawField(fieldName, new BytesArray(query.toString()).streamInput(), query.contentType())
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         querySource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
@@ -1085,7 +1078,7 @@ public void testDuplicatedClauses() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, qb).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
 
@@ -1110,7 +1103,7 @@ public void testDuplicatedClauses() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, qb).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
 
@@ -1138,7 +1131,7 @@ public void testDuplicatedClauses() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field(fieldName, qb).endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
 
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhaseTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhaseTests.java
index 83ca9037658b5..18ab11864397f 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhaseTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorHighlightSubFetchPhaseTests.java
@@ -38,17 +38,18 @@
 import org.apache.lucene.search.DisjunctionMaxQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.lucene.search.function.RandomScoreFunction;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.search.fetch.FetchContext;
 import org.opensearch.search.fetch.subphase.highlight.SearchHighlightContext;
 import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.Mockito;
 
 import java.util.Arrays;
 import java.util.Collections;
 
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyMap;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhaseTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhaseTests.java
index efa5a7a3d5095..ffb1764d7f3d6 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhaseTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorMatchedSlotSubFetchPhaseTests.java
@@ -36,7 +36,6 @@
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.memory.MemoryIndex;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -46,6 +45,7 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.FixedBitSet;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.search.SearchHit;
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorQuerySearchTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorQuerySearchTests.java
index 1d77c9d472864..07c7234dff587 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorQuerySearchTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/PercolatorQuerySearchTests.java
@@ -35,11 +35,11 @@
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
 import org.opensearch.index.engine.Engine;
@@ -115,7 +115,7 @@ public void testPercolateScriptQuery() throws IOException {
                 new PercolateQueryBuilder(
                     "query",
                     BytesReference.bytes(jsonBuilder().startObject().field("field1", "b").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .get();
@@ -188,7 +188,7 @@ public void testPercolateQueryWithNestedDocuments_doNotLeakBitsetCacheEntries()
                                 .endArray()
                                 .endObject()
                         ),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 )
                 .addSort("_doc", SortOrder.ASC)
@@ -269,7 +269,7 @@ public void testPercolateQueryWithNestedDocuments_doLeakFieldDataCacheEntries()
         doc.endObject();
         for (int i = 0; i < 32; i++) {
             SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", BytesReference.bytes(doc), XContentType.JSON))
+                .setQuery(new PercolateQueryBuilder("query", BytesReference.bytes(doc), MediaTypeRegistry.JSON))
                 .addSort("_doc", SortOrder.ASC)
                 .get();
             assertHitCount(response, 1);
@@ -293,7 +293,7 @@ public void testMapUnmappedFieldAsText() throws IOException {
                 new PercolateQueryBuilder(
                     "query",
                     BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             )
             .get();
@@ -348,13 +348,13 @@ public void testRangeQueriesWithNow() throws Exception {
             BytesReference source = BytesReference.bytes(
                 jsonBuilder().startObject().field("field1", "value").field("field2", currentTime[0]).endObject()
             );
-            QueryBuilder queryBuilder = new PercolateQueryBuilder("query", source, XContentType.JSON);
+            QueryBuilder queryBuilder = new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON);
             Query query = queryBuilder.toQuery(queryShardContext);
             assertThat(searcher.count(query), equalTo(3));
 
             currentTime[0] = currentTime[0] + 10800000; // + 3 hours
             source = BytesReference.bytes(jsonBuilder().startObject().field("field1", "value").field("field2", currentTime[0]).endObject());
-            queryBuilder = new PercolateQueryBuilder("query", source, XContentType.JSON);
+            queryBuilder = new PercolateQueryBuilder("query", source, MediaTypeRegistry.JSON);
             query = queryBuilder.toQuery(queryShardContext);
             assertThat(searcher.count(query), equalTo(3));
         }
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/QueryAnalyzerTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/QueryAnalyzerTests.java
index 509f483bcd253..9699fb741a678 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/QueryAnalyzerTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/QueryAnalyzerTests.java
@@ -51,6 +51,7 @@
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.sandbox.document.HalfFloatPoint;
 import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
@@ -65,7 +66,6 @@
 import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TermRangeQuery;
-import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.join.QueryBitSetProducer;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.util.BytesRef;
diff --git a/modules/percolator/src/test/java/org/opensearch/percolator/QueryBuilderStoreTests.java b/modules/percolator/src/test/java/org/opensearch/percolator/QueryBuilderStoreTests.java
index 965b64d94ef96..340d359f85523 100644
--- a/modules/percolator/src/test/java/org/opensearch/percolator/QueryBuilderStoreTests.java
+++ b/modules/percolator/src/test/java/org/opensearch/percolator/QueryBuilderStoreTests.java
@@ -41,13 +41,12 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
-import org.mockito.Mockito;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.fielddata.plain.BytesBinaryIndexFieldData;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.ContentPath;
@@ -63,6 +62,8 @@
 import java.io.IOException;
 import java.util.Collections;
 
+import org.mockito.Mockito;
+
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/modules/rank-eval/src/internalClusterTest/java/org/opensearch/index/rankeval/RankEvalRequestIT.java b/modules/rank-eval/src/internalClusterTest/java/org/opensearch/index/rankeval/RankEvalRequestIT.java
index ea80b59711b8a..5b6dcbe482d04 100644
--- a/modules/rank-eval/src/internalClusterTest/java/org/opensearch/index/rankeval/RankEvalRequestIT.java
+++ b/modules/rank-eval/src/internalClusterTest/java/org/opensearch/index/rankeval/RankEvalRequestIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.index.rankeval;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -43,7 +47,7 @@
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.util.ArrayList;
@@ -54,15 +58,33 @@
 import java.util.Set;
 
 import static org.opensearch.index.rankeval.EvaluationMetric.filterUnratedDocuments;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class RankEvalRequestIT extends OpenSearchIntegTestCase {
+public class RankEvalRequestIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String TEST_INDEX = "test";
     private static final String INDEX_ALIAS = "alias0";
     private static final int RELEVANT_RATING_1 = 1;
 
+    public RankEvalRequestIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(RankEvalPlugin.class);
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/DiscountedCumulativeGain.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/DiscountedCumulativeGain.java
index 35db325b70ca5..31c52cab404c6 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/DiscountedCumulativeGain.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/DiscountedCumulativeGain.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
 import java.io.IOException;
@@ -49,8 +49,8 @@
 import java.util.OptionalInt;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.index.rankeval.EvaluationMetric.joinHitsWithRatings;
 
 /**
@@ -282,11 +282,9 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
             return builder;
         }
 
-        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(
-            NAME,
-            true,
-            args -> { return new Detail((Double) args[0], (Double) args[1] != null ? (Double) args[1] : 0.0d, (Integer) args[2]); }
-        );
+        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(NAME, true, args -> {
+            return new Detail((Double) args[0], (Double) args[1] != null ? (Double) args[1] : 0.0d, (Integer) args[2]);
+        });
 
         static {
             PARSER.declareDouble(constructorArg(), DCG_FIELD);
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvalQueryQuality.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvalQueryQuality.java
index 28f0a2f334ee0..b08f6bee571d5 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvalQueryQuality.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvalQueryQuality.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.index.rankeval.RatedDocument.DocumentKey;
 
 import java.io.IOException;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvaluationMetric.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvaluationMetric.java
index 70a6e24d27478..5330121cd1295 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvaluationMetric.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/EvaluationMetric.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.index.rankeval.RatedDocument.DocumentKey;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/ExpectedReciprocalRank.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/ExpectedReciprocalRank.java
index 3557e0576bb05..6d7f90fb63659 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/ExpectedReciprocalRank.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/ExpectedReciprocalRank.java
@@ -33,12 +33,12 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
 import java.io.IOException;
@@ -47,8 +47,8 @@
 import java.util.Objects;
 import java.util.OptionalInt;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.index.rankeval.EvaluationMetric.joinHitsWithRatings;
 
 /**
@@ -262,11 +262,9 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
             return builder.field(UNRATED_FIELD.getPreferredName(), this.unratedDocs);
         }
 
-        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(
-            NAME,
-            true,
-            args -> { return new Detail((Integer) args[0]); }
-        );
+        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(NAME, true, args -> {
+            return new Detail((Integer) args[0]);
+        });
 
         static {
             PARSER.declareInt(constructorArg(), UNRATED_FIELD);
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MeanReciprocalRank.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MeanReciprocalRank.java
index 59792537e89e5..bc455f30f092b 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MeanReciprocalRank.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MeanReciprocalRank.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
 import java.io.IOException;
@@ -45,8 +45,8 @@
 import java.util.Objects;
 import java.util.OptionalInt;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.index.rankeval.EvaluationMetric.joinHitsWithRatings;
 
 /**
@@ -219,11 +219,9 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
             return builder.field(FIRST_RELEVANT_RANK_FIELD.getPreferredName(), firstRelevantRank);
         }
 
-        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(
-            NAME,
-            true,
-            args -> { return new Detail((Integer) args[0]); }
-        );
+        private static final ConstructingObjectParser<Detail, Void> PARSER = new ConstructingObjectParser<>(NAME, true, args -> {
+            return new Detail((Integer) args[0]);
+        });
 
         static {
             PARSER.declareInt(constructorArg(), FIRST_RELEVANT_RANK_FIELD);
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MetricDetail.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MetricDetail.java
index 788c2e2993724..5627ac37a47fc 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MetricDetail.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/MetricDetail.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/PrecisionAtK.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/PrecisionAtK.java
index a5a8dcab34945..531db06ef3cfb 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/PrecisionAtK.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/PrecisionAtK.java
@@ -32,23 +32,23 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
+import javax.naming.directory.SearchResult;
+
 import java.io.IOException;
 import java.util.List;
 import java.util.Objects;
 import java.util.OptionalInt;
 
-import javax.naming.directory.SearchResult;
-
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.index.rankeval.EvaluationMetric.joinHitsWithRatings;
 
 /**
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalNamedXContentProvider.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalNamedXContentProvider.java
index da59a73858957..c6b589ee77515 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalNamedXContentProvider.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalNamedXContentProvider.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.plugins.spi.NamedXContentProvider;
 
 import java.util.ArrayList;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalPlugin.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalPlugin.java
index a1eaa0f62f0f1..9cfc122473673 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalPlugin.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalPlugin.java
@@ -33,15 +33,15 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.NamedXContentRegistry.Entry;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry.Entry;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.rest.RestController;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequest.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequest.java
index 66db397865a0b..5fd1826ff8215 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequest.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequest.java
@@ -39,9 +39,9 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequestBuilder.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequestBuilder.java
index 84fc45527ec27..f3fdb486bd070 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequestBuilder.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalRequestBuilder.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.OpenSearchClient;
 
 public class RankEvalRequestBuilder extends ActionRequestBuilder<RankEvalRequest, RankEvalResponse> {
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalResponse.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalResponse.java
index 23b42846458a2..880032ede01a2 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalResponse.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalResponse.java
@@ -33,17 +33,18 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -105,7 +106,7 @@ public Map<String, Exception> getFailures() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalSpec.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalSpec.java
index 8708c94c353e4..229782b5fb5d1 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalSpec.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RankEvalSpec.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.script.Script;
 
 import java.io.IOException;
@@ -249,7 +250,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedDocument.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedDocument.java
index 5f9a71cd25e7b..afb454025dd01 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedDocument.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedDocument.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -128,7 +129,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedRequest.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedRequest.java
index 5289a3945db52..bb05da0682aed 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedRequest.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedRequest.java
@@ -33,15 +33,16 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.rankeval.RatedDocument.DocumentKey;
 import org.opensearch.search.builder.SearchSourceBuilder;
 
@@ -340,7 +341,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedSearchHit.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedSearchHit.java
index 01c1c81f2bf2a..f7b2b7a890334 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedSearchHit.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RatedSearchHit.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
 import java.io.IOException;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RecallAtK.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RecallAtK.java
index 4edd23133d2ec..90c1f4951269e 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RecallAtK.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RecallAtK.java
@@ -32,23 +32,23 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 
+import javax.naming.directory.SearchResult;
+
 import java.io.IOException;
 import java.util.List;
 import java.util.Objects;
 import java.util.OptionalInt;
 
-import javax.naming.directory.SearchResult;
-
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.index.rankeval.EvaluationMetric.joinHitsWithRatings;
 
 /**
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RestRankEvalAction.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RestRankEvalAction.java
index 3c8748d13da0d..cb5138117d0e1 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RestRankEvalAction.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/RestRankEvalAction.java
@@ -35,8 +35,8 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
diff --git a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/TransportRankEvalAction.java b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/TransportRankEvalAction.java
index 8cfde2d2b412e..1fe5a2840fae6 100644
--- a/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/TransportRankEvalAction.java
+++ b/modules/rank-eval/src/main/java/org/opensearch/index/rankeval/TransportRankEvalAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.MultiSearchResponse.Item;
@@ -40,13 +39,14 @@
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.Client;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.TemplateScript;
@@ -126,7 +126,7 @@ protected void doExecute(Task task, RankEvalRequest request, ActionListener<Rank
                         namedXContentRegistry,
                         LoggingDeprecationHandler.INSTANCE,
                         new BytesArray(resolvedRequest),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                 ) {
                     evaluationRequest = SearchSourceBuilder.fromXContent(subParser, false);
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/DiscountedCumulativeGainTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/DiscountedCumulativeGainTests.java
index 2b1c56d9bba3b..fcf1fa489f740 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/DiscountedCumulativeGainTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/DiscountedCumulativeGainTests.java
@@ -33,17 +33,17 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -274,7 +274,7 @@ public static DiscountedCumulativeGain createTestItem() {
 
     public void testXContentRoundtrip() throws IOException {
         DiscountedCumulativeGain testItem = createTestItem();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
@@ -323,10 +323,13 @@ public void testMetricDetails() {
                     + ",\"unrated_docs\":"
                     + unratedDocs
                     + "}}",
-                Strings.toString(detail)
+                Strings.toString(MediaTypeRegistry.JSON, detail)
             );
         } else {
-            assertEquals("{\"dcg\":{\"dcg\":" + dcg + ",\"unrated_docs\":" + unratedDocs + "}}", Strings.toString(detail));
+            assertEquals(
+                "{\"dcg\":{\"dcg\":" + dcg + ",\"unrated_docs\":" + unratedDocs + "}}",
+                Strings.toString(MediaTypeRegistry.JSON, detail)
+            );
         }
     }
 
@@ -343,11 +346,9 @@ public void testSerialization() throws IOException {
     }
 
     public void testEqualsAndHash() throws IOException {
-        checkEqualsAndHashCode(
-            createTestItem(),
-            original -> { return new DiscountedCumulativeGain(original.getNormalize(), original.getUnknownDocRating(), original.getK()); },
-            DiscountedCumulativeGainTests::mutateTestItem
-        );
+        checkEqualsAndHashCode(createTestItem(), original -> {
+            return new DiscountedCumulativeGain(original.getNormalize(), original.getUnknownDocRating(), original.getK());
+        }, DiscountedCumulativeGainTests::mutateTestItem);
     }
 
     private static DiscountedCumulativeGain mutateTestItem(DiscountedCumulativeGain original) {
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/EvalQueryQualityTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/EvalQueryQualityTests.java
index 56d23d8ca3184..ad58f1909c811 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/EvalQueryQualityTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/EvalQueryQualityTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -48,8 +48,8 @@
 import java.util.List;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/ExpectedReciprocalRankTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/ExpectedReciprocalRankTests.java
index 723a1e2202e2b..d10c6c285e0d7 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/ExpectedReciprocalRankTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/ExpectedReciprocalRankTests.java
@@ -33,16 +33,16 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -166,7 +166,7 @@ public static ExpectedReciprocalRank createTestItem() {
 
     public void testXContentRoundtrip() throws IOException {
         ExpectedReciprocalRank testItem = createTestItem();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
@@ -213,11 +213,9 @@ public void testSerialization() throws IOException {
     }
 
     public void testEqualsAndHash() throws IOException {
-        checkEqualsAndHashCode(
-            createTestItem(),
-            original -> { return new ExpectedReciprocalRank(original.getMaxRelevance(), original.getUnknownDocRating(), original.getK()); },
-            ExpectedReciprocalRankTests::mutateTestItem
-        );
+        checkEqualsAndHashCode(createTestItem(), original -> {
+            return new ExpectedReciprocalRank(original.getMaxRelevance(), original.getUnknownDocRating(), original.getK());
+        }, ExpectedReciprocalRankTests::mutateTestItem);
     }
 
     private static ExpectedReciprocalRank mutateTestItem(ExpectedReciprocalRank original) {
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/MeanReciprocalRankTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/MeanReciprocalRankTests.java
index 2cd16c05f2a20..2304cf74d307f 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/MeanReciprocalRankTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/MeanReciprocalRankTests.java
@@ -33,16 +33,16 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -183,7 +183,7 @@ public void testNoResults() throws Exception {
 
     public void testXContentRoundtrip() throws IOException {
         MeanReciprocalRank testItem = createTestItem();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/PrecisionAtKTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/PrecisionAtKTests.java
index 1c7a02dc27cf7..16e74d928c2b4 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/PrecisionAtKTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/PrecisionAtKTests.java
@@ -33,16 +33,16 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -199,7 +199,7 @@ public static PrecisionAtK createTestItem() {
 
     public void testXContentRoundtrip() throws IOException {
         PrecisionAtK testItem = createTestItem();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalRequestTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalRequestTests.java
index 401bb1b2a7bb7..023edc7827dc5 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalRequestTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalRequestTests.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable.Reader;
 import org.opensearch.common.util.ArrayUtils;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.junit.AfterClass;
 
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalResponseTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalResponseTests.java
index 3d883b373d705..db792130ca016 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalResponseTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalResponseTests.java
@@ -37,20 +37,20 @@
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchParseException;
 import org.opensearch.search.SearchShardTarget;
@@ -67,7 +67,7 @@
 import java.util.function.Predicate;
 
 import static java.util.Collections.singleton;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.TestSearchContext.SHARD_TARGET;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
@@ -76,7 +76,7 @@
 public class RankEvalResponseTests extends OpenSearchTestCase {
 
     private static final Exception[] RANDOM_EXCEPTIONS = new Exception[] {
-        new ClusterBlockException(singleton(NoMasterBlockService.NO_MASTER_BLOCK_WRITES)),
+        new ClusterBlockException(singleton(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES)),
         new CircuitBreakingException("Data too large", 123, 456, CircuitBreaker.Durability.PERMANENT),
         new SearchParseException(SHARD_TARGET, "Parse failure", new XContentLocation(12, 98)),
         new IllegalArgumentException("Closed resource", new RuntimeException("Resource")),
@@ -177,7 +177,7 @@ public void testToXContent() throws IOException {
             Collections.singletonMap("coffee_query", coffeeQueryQuality),
             Collections.singletonMap("beer_query", new ParsingException(new XContentLocation(0, 0), "someMsg"))
         );
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         String xContent = BytesReference.bytes(response.toXContent(builder, ToXContent.EMPTY_PARAMS)).utf8ToString();
         assertEquals(
             ("{"
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalSpecTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalSpecTests.java
index b79b26eb0af2e..c665fe4045cef 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalSpecTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RankEvalSpecTests.java
@@ -32,16 +32,15 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.rankeval.RankEvalSpec.ScriptWithId;
@@ -103,7 +102,7 @@ static RankEvalSpec createTestItem() {
                 builder.startObject();
                 builder.field("field", randomAlphaOfLengthBetween(1, 5));
                 builder.endObject();
-                script = Strings.toString(builder);
+                script = builder.toString();
             } catch (IOException e) {
                 // this shouldn't happen in tests, re-throw just not to swallow it
                 throw new RuntimeException(e);
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedDocumentTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedDocumentTests.java
index f3fb01b153c55..390412674e05e 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedDocumentTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedDocumentTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -57,7 +57,7 @@ public static RatedDocument createRatedDocument() {
 
     public void testXContentParsing() throws IOException {
         RatedDocument testItem = createRatedDocument();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             RatedDocument parsedItem = RatedDocument.fromXContent(itemParser);
@@ -91,11 +91,9 @@ public void testSerialization() throws IOException {
     }
 
     public void testEqualsAndHash() throws IOException {
-        checkEqualsAndHashCode(
-            createRatedDocument(),
-            original -> { return new RatedDocument(original.getIndex(), original.getDocID(), original.getRating()); },
-            RatedDocumentTests::mutateTestItem
-        );
+        checkEqualsAndHashCode(createRatedDocument(), original -> {
+            return new RatedDocument(original.getIndex(), original.getDocID(), original.getRating());
+        }, RatedDocumentTests::mutateTestItem);
     }
 
     private static RatedDocument mutateTestItem(RatedDocument original) {
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedRequestsTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedRequestsTests.java
index a2555c2e1e392..588be3d94c2c6 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedRequestsTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedRequestsTests.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.SearchModule;
@@ -134,7 +134,7 @@ public static RatedRequest createTestItem(boolean forceRequest) {
 
     public void testXContentRoundtrip() throws IOException {
         RatedRequest testItem = createTestItem(randomBoolean());
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedSearchHitTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedSearchHitTests.java
index 555a0c95a3456..69cf329401918 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedSearchHitTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RatedSearchHitTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RecallAtKTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RecallAtKTests.java
index 6efb44a3875e1..e89d0bcb20eef 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RecallAtKTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/RecallAtKTests.java
@@ -33,16 +33,16 @@
 package org.opensearch.index.rankeval;
 
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -185,7 +185,7 @@ public static RecallAtK createTestItem() {
 
     public void testXContentRoundtrip() throws IOException {
         RecallAtK testItem = createTestItem();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         XContentBuilder shuffled = shuffleXContent(testItem.toXContent(builder, ToXContent.EMPTY_PARAMS));
         try (XContentParser itemParser = createParser(shuffled)) {
             itemParser.nextToken();
diff --git a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/TransportRankEvalActionTests.java b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/TransportRankEvalActionTests.java
index b2052bcb79255..bd42289015bf4 100644
--- a/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/TransportRankEvalActionTests.java
+++ b/modules/rank-eval/src/test/java/org/opensearch/index/rankeval/TransportRankEvalActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.rankeval;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchType;
@@ -40,7 +39,8 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.builder.SearchSourceBuilder;
diff --git a/modules/reindex/src/internalClusterTest/java/org/opensearch/client/documentation/ReindexDocumentationIT.java b/modules/reindex/src/internalClusterTest/java/org/opensearch/client/documentation/ReindexDocumentationIT.java
index 6d313e06263b3..59d079535f58b 100644
--- a/modules/reindex/src/internalClusterTest/java/org/opensearch/client/documentation/ReindexDocumentationIT.java
+++ b/modules/reindex/src/internalClusterTest/java/org/opensearch/client/documentation/ReindexDocumentationIT.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.client.documentation;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.get.GetTaskResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.client.Client;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.query.QueryBuilders;
@@ -53,12 +55,10 @@
 import org.opensearch.index.reindex.UpdateByQueryAction;
 import org.opensearch.index.reindex.UpdateByQueryRequestBuilder;
 import org.opensearch.index.shard.IndexingOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
diff --git a/modules/reindex/src/internalClusterTest/java/org/opensearch/index/codec/MultiCodecReindexIT.java b/modules/reindex/src/internalClusterTest/java/org/opensearch/index/codec/MultiCodecReindexIT.java
new file mode 100644
index 0000000000000..85c652bab1cb0
--- /dev/null
+++ b/modules/reindex/src/internalClusterTest/java/org/opensearch/index/codec/MultiCodecReindexIT.java
@@ -0,0 +1,198 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.codec;
+
+import org.opensearch.action.admin.indices.flush.FlushResponse;
+import org.opensearch.action.admin.indices.refresh.RefreshResponse;
+import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequest;
+import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
+import org.opensearch.action.support.ActiveShardCount;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.engine.Segment;
+import org.opensearch.index.reindex.BulkByScrollResponse;
+import org.opensearch.index.reindex.ReindexAction;
+import org.opensearch.index.reindex.ReindexPlugin;
+import org.opensearch.index.reindex.ReindexRequestBuilder;
+import org.opensearch.index.reindex.ReindexTestCase;
+import org.opensearch.plugins.Plugin;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.ExecutionException;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import static java.util.stream.Collectors.toList;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_METADATA;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_READ;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_WRITE;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_READ_ONLY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_READ_ONLY_ALLOW_DELETE;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
+
+public class MultiCodecReindexIT extends ReindexTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return List.of(ReindexPlugin.class);
+    }
+
+    public void testReindexingMultipleCodecs() throws InterruptedException, ExecutionException {
+        internalCluster().ensureAtLeastNumDataNodes(1);
+        Map<String, String> codecMap = Map.of(
+            "best_compression",
+            "BEST_COMPRESSION",
+            "zlib",
+            "BEST_COMPRESSION",
+            "default",
+            "BEST_SPEED",
+            "lz4",
+            "BEST_SPEED"
+        );
+
+        for (Map.Entry<String, String> codec : codecMap.entrySet()) {
+            assertReindexingWithMultipleCodecs(codec.getKey(), codec.getValue(), codecMap);
+        }
+
+    }
+
+    private void assertReindexingWithMultipleCodecs(String destCodec, String destCodecMode, Map<String, String> codecMap)
+        throws ExecutionException, InterruptedException {
+
+        final String index = "test-index" + destCodec;
+        final String destIndex = "dest-index" + destCodec;
+
+        // creating source index
+        createIndex(
+            index,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .put("index.codec", "default")
+                .put("index.merge.policy.max_merged_segment", "1b")
+                .build()
+        );
+        ensureGreen(index);
+
+        final int nbDocs = randomIntBetween(2, 5);
+
+        // indexing with all 4 codecs
+        for (Map.Entry<String, String> codec : codecMap.entrySet()) {
+            useCodec(index, codec.getKey());
+            ingestDocs(index, nbDocs);
+        }
+
+        assertTrue(
+            getSegments(index).stream()
+                .flatMap(s -> s.getAttributes().values().stream())
+                .collect(Collectors.toSet())
+                .containsAll(codecMap.values())
+        );
+
+        // creating destination index with destination codec
+        createIndex(
+            destIndex,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .put("index.codec", destCodec)
+                .build()
+        );
+
+        BulkByScrollResponse bulkResponse = new ReindexRequestBuilder(client(), ReindexAction.INSTANCE).source(index)
+            .destination(destIndex)
+            .refresh(true)
+            .waitForActiveShards(ActiveShardCount.ONE)
+            .get();
+
+        assertEquals(codecMap.size() * nbDocs, bulkResponse.getCreated());
+        assertEquals(codecMap.size() * nbDocs, bulkResponse.getTotal());
+        assertEquals(0, bulkResponse.getDeleted());
+        assertEquals(0, bulkResponse.getNoops());
+        assertEquals(0, bulkResponse.getVersionConflicts());
+        assertEquals(1, bulkResponse.getBatches());
+        assertTrue(bulkResponse.getTook().getMillis() > 0);
+        assertEquals(0, bulkResponse.getBulkFailures().size());
+        assertEquals(0, bulkResponse.getSearchFailures().size());
+        assertTrue(getSegments(destIndex).stream().allMatch(segment -> segment.attributes.containsValue(destCodecMode)));
+    }
+
+    private void useCodec(String index, String codec) throws ExecutionException, InterruptedException {
+        assertAcked(client().admin().indices().prepareClose(index).setWaitForActiveShards(1));
+
+        assertAcked(
+            client().admin()
+                .indices()
+                .updateSettings(new UpdateSettingsRequest(index).settings(Settings.builder().put("index.codec", codec)))
+                .get()
+        );
+
+        assertAcked(client().admin().indices().prepareOpen(index).setWaitForActiveShards(1));
+    }
+
+    private void flushAndRefreshIndex(String index) {
+
+        // Request is not blocked
+        for (String blockSetting : Arrays.asList(
+            SETTING_BLOCKS_READ,
+            SETTING_BLOCKS_WRITE,
+            SETTING_READ_ONLY,
+            SETTING_BLOCKS_METADATA,
+            SETTING_READ_ONLY_ALLOW_DELETE
+        )) {
+            try {
+                enableIndexBlock(index, blockSetting);
+                // flush
+                FlushResponse flushResponse = client().admin().indices().prepareFlush(index).setForce(true).execute().actionGet();
+                assertNoFailures(flushResponse);
+
+                // refresh
+                RefreshResponse refreshResponse = client().admin().indices().prepareRefresh(index).execute().actionGet();
+                assertNoFailures(refreshResponse);
+            } finally {
+                disableIndexBlock(index, blockSetting);
+            }
+        }
+    }
+
+    private void ingestDocs(String index, int nbDocs) throws InterruptedException {
+
+        indexRandom(
+            randomBoolean(),
+            false,
+            randomBoolean(),
+            IntStream.range(0, nbDocs)
+                .mapToObj(i -> client().prepareIndex(index).setId(UUID.randomUUID().toString()).setSource("num", i))
+                .collect(toList())
+        );
+        flushAndRefreshIndex(index);
+    }
+
+    private ArrayList<Segment> getSegments(String index) {
+
+        return new ArrayList<>(
+            client().admin()
+                .indices()
+                .segments(new IndicesSegmentsRequest(index))
+                .actionGet()
+                .getIndices()
+                .get(index)
+                .getShards()
+                .get(0)
+                .getShards()[0].getSegments()
+        );
+    }
+
+}
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollAction.java
index 43adffc6f7671..e6c1cde5c0e98 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollAction.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.index.reindex;
 
-import java.util.Optional;
 import org.apache.http.HttpRequestInterceptor;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
@@ -52,9 +50,10 @@
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.client.ParentTaskAssigningClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IndexFieldMapper;
@@ -79,6 +78,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
@@ -90,8 +90,8 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.action.bulk.BackoffPolicy.exponentialBackoff;
 import static org.opensearch.common.unit.TimeValue.timeValueNanos;
+import static org.opensearch.core.rest.RestStatus.CONFLICT;
 import static org.opensearch.index.reindex.AbstractBulkByScrollRequest.MAX_DOCS_ALL_MATCHES;
-import static org.opensearch.rest.RestStatus.CONFLICT;
 import static org.opensearch.search.sort.SortBuilders.fieldSort;
 
 /**
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBaseReindexRestHandler.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBaseReindexRestHandler.java
index a0696ea1b72ea..f034e92551ede 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBaseReindexRestHandler.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBaseReindexRestHandler.java
@@ -36,14 +36,10 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.rest.BaseRestHandler;
-import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.LoggingTaskListener;
-import org.opensearch.tasks.Task;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -124,17 +120,6 @@ protected Request setCommonOptions(RestRequest restRequest, Request request) {
         return request;
     }
 
-    private RestChannelConsumer sendTask(String localNodeId, Task task) {
-        return channel -> {
-            try (XContentBuilder builder = channel.newBuilder()) {
-                builder.startObject();
-                builder.field("task", localNodeId + ":" + task.getId());
-                builder.endObject();
-                channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
-            }
-        };
-    }
-
     private static Integer parseSlices(RestRequest request) {
         String slicesString = request.param("slices");
         if (slicesString == null) {
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBulkByQueryRestHandler.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBulkByQueryRestHandler.java
index 512e7f430b7c5..96e15a3899383 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBulkByQueryRestHandler.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractBulkByQueryRestHandler.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.action.ActionType;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.search.RestSearchAction;
 
@@ -106,7 +106,7 @@ private XContentParser extractRequestSpecificFields(RestRequest restRequest, Map
         }
         try (
             XContentParser parser = restRequest.contentOrSourceParamParser();
-            XContentBuilder builder = XContentFactory.contentBuilder(parser.contentType())
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(parser.contentType())
         ) {
             Map<String, Object> body = parser.map();
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/AsyncDeleteByQueryAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/AsyncDeleteByQueryAction.java
index 1a9ce16acc255..fefd7fd280082 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/AsyncDeleteByQueryAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/AsyncDeleteByQueryAction.java
@@ -33,9 +33,9 @@
 package org.opensearch.index.reindex;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.client.ParentTaskAssigningClient;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkByScrollParallelizationHelper.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkByScrollParallelizationHelper.java
index 334390ca730cf..d5a6e392f2019 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkByScrollParallelizationHelper.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkByScrollParallelizationHelper.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.slice.SliceBuilder;
-import org.opensearch.tasks.TaskId;
 
 import java.util.Arrays;
 import java.util.Collections;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkIndexByScrollResponseContentListener.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkIndexByScrollResponseContentListener.java
index a41eb12cdd12b..b9367d352fdb1 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkIndexByScrollResponseContentListener.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/BulkIndexByScrollResponseContentListener.java
@@ -33,13 +33,13 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.action.bulk.BulkItemResponse.Failure;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.reindex.ScrollableHitSource.SearchFailure;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.util.Map;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexPlugin.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexPlugin.java
index 865ae26f6f54d..cab1a1dedb3b8 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexPlugin.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexPlugin.java
@@ -32,29 +32,27 @@
 
 package org.opensearch.index.reindex;
 
-import java.util.Optional;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.index.reindex.spi.RemoteReindexExtension;
-import org.opensearch.plugins.ExtensiblePlugin;
-import org.opensearch.plugins.ExtensiblePlugin.ExtensionLoader;
-import org.opensearch.watcher.ResourceWatcherService;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.reindex.spi.RemoteReindexExtension;
 import org.opensearch.plugins.ActionPlugin;
+import org.opensearch.plugins.ExtensiblePlugin;
+import org.opensearch.plugins.ExtensiblePlugin.ExtensionLoader;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.rest.RestController;
@@ -69,6 +67,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.function.Supplier;
 
 import static java.util.Collections.singletonList;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexSslConfig.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexSslConfig.java
index f48422d41ea9e..4c2ec4a7f02b5 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexSslConfig.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexSslConfig.java
@@ -35,14 +35,14 @@
 import org.apache.http.conn.ssl.DefaultHostnameVerifier;
 import org.apache.http.conn.ssl.NoopHostnameVerifier;
 import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.ssl.SslConfiguration;
 import org.opensearch.common.ssl.SslConfigurationKeys;
 import org.opensearch.common.ssl.SslConfigurationLoader;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.watcher.FileChangesListener;
 import org.opensearch.watcher.FileWatcher;
@@ -50,6 +50,7 @@
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
+
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.file.Path;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexValidator.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexValidator.java
index 71c3aad8713e1..d065afceab503 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexValidator.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/ReindexValidator.java
@@ -45,10 +45,10 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.search.builder.SearchSourceBuilder;
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/Reindexer.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/Reindexer.java
index 8ade055d10f60..8e338dedc4ec8 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/Reindexer.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/Reindexer.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.reindex;
 
-import java.util.Optional;
 import org.apache.http.Header;
 import org.apache.http.HttpHost;
 import org.apache.http.HttpRequestInterceptor;
@@ -44,7 +43,6 @@
 import org.apache.http.message.BasicHeader;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.action.bulk.BulkItemResponse;
@@ -54,14 +52,15 @@
 import org.opensearch.client.RestClient;
 import org.opensearch.client.RestClientBuilder;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.VersionFieldMapper;
 import org.opensearch.index.reindex.remote.RemoteScrollableHitSource;
@@ -77,6 +76,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiFunction;
 
@@ -368,27 +368,24 @@ protected RequestWrapper<IndexRequest> buildRequest(ScrollableHitSource.Hit doc)
             index.id(doc.getId());
 
             // the source xcontent type and destination could be different
-            final XContentType sourceXContentType = doc.getXContentType();
-            final XContentType mainRequestXContentType = mainRequest.getDestination().getContentType();
-            if (mainRequestXContentType != null && doc.getXContentType() != mainRequestXContentType) {
+            final MediaType sourceMediaType = doc.getMediaType();
+            final MediaType mainRequestMediaType = mainRequest.getDestination().getContentType();
+            if (mainRequestMediaType != null && doc.getMediaType() != mainRequestMediaType) {
                 // we need to convert
                 try (
                     InputStream stream = doc.getSource().streamInput();
-                    XContentParser parser = sourceXContentType.xContent()
+                    XContentParser parser = sourceMediaType.xContent()
                         .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, stream);
-                    XContentBuilder builder = XContentBuilder.builder(mainRequestXContentType.xContent())
+                    XContentBuilder builder = XContentBuilder.builder(mainRequestMediaType.xContent())
                 ) {
                     parser.nextToken();
                     builder.copyCurrentStructure(parser);
                     index.source(BytesReference.bytes(builder), builder.contentType());
                 } catch (IOException e) {
-                    throw new UncheckedIOException(
-                        "failed to convert hit from " + sourceXContentType + " to " + mainRequestXContentType,
-                        e
-                    );
+                    throw new UncheckedIOException("failed to convert hit from " + sourceMediaType + " to " + mainRequestMediaType, e);
                 }
             } else {
-                index.source(doc.getSource(), doc.getXContentType());
+                index.source(doc.getSource(), doc.getMediaType());
             }
 
             /*
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestDeleteByQueryAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestDeleteByQueryAction.java
index 6f2e5d8e71edb..4f68884b194e9 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestDeleteByQueryAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestDeleteByQueryAction.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.rest.RestRequest;
 
 import java.io.IOException;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestReindexAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestReindexAction.java
index 9fb30876c3e3c..c03eba10b41ba 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestReindexAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestReindexAction.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestRequestFilter;
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestRethrottleAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestRethrottleAction.java
index 89864cf56c71d..925cada3e40b5 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestRethrottleAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestRethrottleAction.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.tasks.TaskId;
 
 import java.util.List;
 import java.util.function.Supplier;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestUpdateByQueryAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestUpdateByQueryAction.java
index 9be1687a09432..aeb339d49e1bb 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/RestUpdateByQueryAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/RestUpdateByQueryAction.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.script.Script;
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/RethrottleRequest.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/RethrottleRequest.java
index f174aa6d6fda3..2036479c73bc4 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/RethrottleRequest.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/RethrottleRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.tasks.BaseTasksRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportDeleteByQueryAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportDeleteByQueryAction.java
index 51e388227eb10..299626bd7fd22 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportDeleteByQueryAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportDeleteByQueryAction.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.Client;
 import org.opensearch.client.ParentTaskAssigningClient;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportReindexAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportReindexAction.java
index c84d103a2ef6f..e624b0619a26e 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportReindexAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportReindexAction.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.index.reindex;
 
-import java.util.Optional;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.AutoCreateIndex;
 import org.opensearch.action.support.HandledTransportAction;
@@ -44,6 +42,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.reindex.spi.RemoteReindexExtension;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
@@ -51,6 +50,7 @@
 import org.opensearch.transport.TransportService;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.function.Function;
 
 import static java.util.Collections.emptyList;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportRethrottleAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportRethrottleAction.java
index 2ee869ce2b465..21ae8fd722629 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportRethrottleAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportRethrottleAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.index.reindex;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
@@ -42,7 +41,8 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportUpdateByQueryAction.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportUpdateByQueryAction.java
index f07915b9d9e76..1af9b62d72fd4 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportUpdateByQueryAction.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/TransportUpdateByQueryAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.index.reindex;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
@@ -42,7 +41,8 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IndexFieldMapper;
 import org.opensearch.index.mapper.RoutingFieldMapper;
@@ -138,7 +138,7 @@ protected RequestWrapper<IndexRequest> buildRequest(ScrollableHitSource.Hit doc)
             IndexRequest index = new IndexRequest();
             index.index(doc.getIndex());
             index.id(doc.getId());
-            index.source(doc.getSource(), doc.getXContentType());
+            index.source(doc.getSource(), doc.getMediaType());
             index.setIfSeqNo(doc.getSeqNo());
             index.setIfPrimaryTerm(doc.getPrimaryTerm());
             index.setPipeline(mainRequest.getPipeline());
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteRequestBuilders.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteRequestBuilders.java
index 8467fbdeacd0e..6886ca9420091 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteRequestBuilders.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteRequestBuilders.java
@@ -38,16 +38,15 @@
 import org.opensearch.Version;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.client.Request;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.SortBuilder;
 
@@ -181,7 +180,7 @@ static Request initialSearch(SearchRequest searchRequest, BytesReference query,
             }
 
             entity.endObject();
-            request.setJsonEntity(Strings.toString(entity));
+            request.setJsonEntity(entity.toString());
         } catch (IOException e) {
             throw new OpenSearchException("unexpected error building entity", e);
         }
@@ -246,7 +245,7 @@ static Request scroll(String scroll, TimeValue keepAlive, Version remoteVersion)
 
         try (XContentBuilder entity = JsonXContent.contentBuilder()) {
             entity.startObject().field("scroll_id", scroll).endObject();
-            request.setJsonEntity(Strings.toString(entity));
+            request.setJsonEntity(entity.toString());
         } catch (IOException e) {
             throw new OpenSearchException("failed to build scroll entity", e);
         }
@@ -263,7 +262,7 @@ static Request clearScroll(String scroll, Version remoteVersion) {
         }
         try (XContentBuilder entity = JsonXContent.contentBuilder()) {
             entity.startObject().array("scroll_id", scroll).endObject();
-            request.setJsonEntity(Strings.toString(entity));
+            request.setJsonEntity(entity.toString());
         } catch (IOException e) {
             throw new OpenSearchException("failed to build clear scroll entity", e);
         }
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteResponseParsers.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteResponseParsers.java
index d22b995036e90..981a22d4e7945 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteResponseParsers.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteResponseParsers.java
@@ -35,18 +35,18 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.reindex.ScrollableHitSource.BasicHit;
 import org.opensearch.index.reindex.ScrollableHitSource.Hit;
 import org.opensearch.index.reindex.ScrollableHitSource.Response;
@@ -60,8 +60,8 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static java.util.Objects.requireNonNull;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Parsers to convert the response from the remote host into objects useful for {@link RemoteScrollableHitSource}.
@@ -72,7 +72,7 @@ private RemoteResponseParsers() {}
     /**
      * Parser for an individual {@code hit} element.
      */
-    public static final ConstructingObjectParser<BasicHit, XContentType> HIT_PARSER = new ConstructingObjectParser<>("hit", true, a -> {
+    public static final ConstructingObjectParser<BasicHit, MediaType> HIT_PARSER = new ConstructingObjectParser<>("hit", true, a -> {
         int i = 0;
         String index = (String) a[i++];
         String id = (String) a[i++];
@@ -106,7 +106,7 @@ private RemoteResponseParsers() {}
         class Fields {
             String routing;
         }
-        ObjectParser<Fields, XContentType> fieldsParser = new ObjectParser<>("fields", Fields::new);
+        ObjectParser<Fields, MediaType> fieldsParser = new ObjectParser<>("fields", Fields::new);
         HIT_PARSER.declareObject((hit, fields) -> { hit.setRouting(fields.routing); }, fieldsParser, new ParseField("fields"));
         fieldsParser.declareString((fields, routing) -> fields.routing = routing, routingField);
         fieldsParser.declareLong((fields, ttl) -> {}, ttlField); // ignore ttls since they have been removed
@@ -116,7 +116,7 @@ class Fields {
     /**
      * Parser for the {@code hits} element. Parsed to an array of {@code [total (Long), hits (List<Hit>)]}.
      */
-    public static final ConstructingObjectParser<Object[], XContentType> HITS_PARSER = new ConstructingObjectParser<>("hits", true, a -> a);
+    public static final ConstructingObjectParser<Object[], MediaType> HITS_PARSER = new ConstructingObjectParser<>("hits", true, a -> a);
     static {
         HITS_PARSER.declareField(constructorArg(), (p, c) -> {
             if (p.currentToken() == XContentParser.Token.START_OBJECT) {
@@ -184,7 +184,7 @@ class Fields {
         SHARDS_PARSER.declareObjectArray(optionalConstructorArg(), SEARCH_FAILURE_PARSER, new ParseField("failures"));
     }
 
-    public static final ConstructingObjectParser<Response, XContentType> RESPONSE_PARSER = new ConstructingObjectParser<>(
+    public static final ConstructingObjectParser<Response, MediaType> RESPONSE_PARSER = new ConstructingObjectParser<>(
         "search_response",
         true,
         a -> {
@@ -296,13 +296,13 @@ public void setCausedBy(Throwable causedBy) {
     /**
      * Parses the main action to return just the {@linkplain Version} that it returns. We throw everything else out.
      */
-    public static final ConstructingObjectParser<Version, XContentType> MAIN_ACTION_PARSER = new ConstructingObjectParser<>(
+    public static final ConstructingObjectParser<Version, MediaType> MAIN_ACTION_PARSER = new ConstructingObjectParser<>(
         "/",
         true,
         a -> (Version) a[0]
     );
     static {
-        ConstructingObjectParser<Version, XContentType> versionParser = new ConstructingObjectParser<>(
+        ConstructingObjectParser<Version, MediaType> versionParser = new ConstructingObjectParser<>(
             "version",
             true,
             a -> a[0] == null
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSource.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSource.java
index be691243ecf84..dc1cddca4bd55 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSource.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSource.java
@@ -49,18 +49,18 @@
 import org.opensearch.client.ResponseListener;
 import org.opensearch.client.RestClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.reindex.RejectAwareActionListener;
 import org.opensearch.index.reindex.ScrollableHitSource;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -181,7 +181,7 @@ protected void cleanup(Runnable onCompletion) {
 
     private <T> void execute(
         Request request,
-        BiFunction<XContentParser, XContentType, T> parser,
+        BiFunction<XContentParser, MediaType, T> parser,
         RejectAwareActionListener<? super T> listener
     ) {
         // Preserve the thread context so headers survive after the call
@@ -197,12 +197,12 @@ public void onSuccess(org.opensearch.client.Response response) {
                         try {
                             HttpEntity responseEntity = response.getEntity();
                             InputStream content = responseEntity.getContent();
-                            XContentType xContentType = null;
+                            MediaType mediaType = null;
                             if (responseEntity.getContentType() != null) {
                                 final String mimeType = ContentType.parse(responseEntity.getContentType().getValue()).getMimeType();
-                                xContentType = XContentType.fromMediaType(mimeType);
+                                mediaType = MediaType.fromMediaType(mimeType);
                             }
-                            if (xContentType == null) {
+                            if (mediaType == null) {
                                 try {
                                     logger.debug("Response didn't include Content-Type: " + bodyMessage(response.getEntity()));
                                     throw new OpenSearchException(
@@ -216,10 +216,10 @@ public void onSuccess(org.opensearch.client.Response response) {
                             }
                             // EMPTY is safe here because we don't call namedObject
                             try (
-                                XContentParser xContentParser = xContentType.xContent()
+                                XContentParser xContentParser = mediaType.xContent()
                                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, content)
                             ) {
-                                parsedResponse = parser.apply(xContentParser, xContentType);
+                                parsedResponse = parser.apply(xContentParser, mediaType);
                             } catch (XContentParseException e) {
                                 /* Because we're streaming the response we can't get a copy of it here. The best we can do is hint that it
                                  * is totally wrong and we're probably not talking to Elasticsearch. */
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/ReindexRestInterceptorProvider.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/ReindexRestInterceptorProvider.java
index 034981c969b4b..5af3c2a704529 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/ReindexRestInterceptorProvider.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/ReindexRestInterceptorProvider.java
@@ -5,11 +5,12 @@
 
 package org.opensearch.index.reindex.spi;
 
-import java.util.Optional;
 import org.apache.http.HttpRequestInterceptor;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.index.reindex.ReindexRequest;
 
+import java.util.Optional;
+
 public interface ReindexRestInterceptorProvider {
     /**
      * @param request Reindex request.
diff --git a/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/RemoteReindexExtension.java b/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/RemoteReindexExtension.java
index ce252de292d63..00da543877be2 100644
--- a/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/RemoteReindexExtension.java
+++ b/modules/reindex/src/main/java/org/opensearch/index/reindex/spi/RemoteReindexExtension.java
@@ -5,7 +5,7 @@
 
 package org.opensearch.index.reindex.spi;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.reindex.BulkByScrollResponse;
 import org.opensearch.index.reindex.ReindexRequest;
 
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionScriptTestCase.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionScriptTestCase.java
index 671faef6c5545..1aa1e7e13ea97 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionScriptTestCase.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionScriptTestCase.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.reindex;
 
-import org.junit.Before;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.index.IndexRequest;
@@ -40,6 +39,7 @@
 import org.opensearch.index.reindex.AbstractAsyncBulkByScrollAction.RequestWrapper;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.UpdateScript;
+import org.junit.Before;
 
 import java.util.Collections;
 import java.util.Map;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/AsyncBulkByScrollActionTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/AsyncBulkByScrollActionTests.java
index 145aaaf24fbee..8ddc1ff778982 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/AsyncBulkByScrollActionTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/AsyncBulkByScrollActionTests.java
@@ -33,13 +33,11 @@
 package org.opensearch.index.reindex;
 
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.DocWriteResponse.Result;
@@ -71,23 +69,25 @@
 import org.opensearch.client.ParentTaskAssigningClient;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.index.reindex.ScrollableHitSource.Hit;
 import org.opensearch.index.reindex.ScrollableHitSource.SearchFailure;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
@@ -121,7 +121,6 @@
 import static java.util.Collections.singleton;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.synchronizedSet;
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.opensearch.action.bulk.BackoffPolicy.constantBackoff;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
@@ -135,6 +134,7 @@
 import static org.hamcrest.Matchers.hasToString;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class AsyncBulkByScrollActionTests extends OpenSearchTestCase {
     private MyMockClient client;
@@ -448,7 +448,7 @@ protected AbstractAsyncBulkByScrollAction.RequestWrapper<?> buildRequest(Hit doc
             }
         };
         ScrollableHitSource.BasicHit hit = new ScrollableHitSource.BasicHit("index", "id", 0);
-        hit.setSource(new BytesArray("{}"), XContentType.JSON);
+        hit.setSource(new BytesArray("{}"), MediaTypeRegistry.JSON);
         ScrollableHitSource.Response response = new ScrollableHitSource.Response(false, emptyList(), 1, singletonList(hit), null);
         simulateScrollResponse(action, System.nanoTime(), 0, response);
         ExecutionException e = expectThrows(ExecutionException.class, () -> listener.get());
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/CancelTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/CancelTests.java
index bd43f05225f65..1ad5b385d5676 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/CancelTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/CancelTests.java
@@ -35,22 +35,22 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.ingest.DeletePipelineRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.Engine.Operation.Origin;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.shard.IndexingOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.ingest.IngestTestPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.tasks.TaskCancelledException;
 import org.opensearch.tasks.TaskInfo;
 import org.hamcrest.Matcher;
 import org.junit.Before;
@@ -263,7 +263,7 @@ public void testUpdateByQueryCancel() throws Exception {
                 + "  } ]\n"
                 + "}"
         );
-        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, XContentType.JSON).get());
+        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, MediaTypeRegistry.JSON).get());
 
         testCancel(UpdateByQueryAction.NAME, updateByQuery().setPipeline("set-processed").source(INDEX), (response, total, modified) -> {
             assertThat(response, matcher().updated(modified).reasonCancelled(equalTo("by user request")));
@@ -307,7 +307,7 @@ public void testUpdateByQueryCancelWithWorkers() throws Exception {
                 + "  } ]\n"
                 + "}"
         );
-        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, XContentType.JSON).get());
+        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, MediaTypeRegistry.JSON).get());
 
         testCancel(
             UpdateByQueryAction.NAME,
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ClientScrollableHitSourceTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ClientScrollableHitSourceTests.java
index 9333e5bd3dcc9..9a6eb7e7fc2ae 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ClientScrollableHitSourceTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ClientScrollableHitSourceTests.java
@@ -33,9 +33,7 @@
 package org.opensearch.index.reindex;
 
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.action.search.SearchAction;
@@ -45,14 +43,16 @@
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.client.ParentTaskAssigningClient;
 import org.opensearch.client.support.AbstractClient;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.internal.InternalSearchResponse;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -69,9 +69,9 @@
 import java.util.stream.IntStream;
 
 import static java.util.Collections.emptyMap;
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class ClientScrollableHitSourceTests extends OpenSearchTestCase {
 
@@ -105,10 +105,9 @@ private static class ExpectedException extends RuntimeException {
 
     public void testRetryFail() {
         int retries = randomInt(10);
-        ExpectedException ex = expectThrows(
-            ExpectedException.class,
-            () -> { dotestBasicsWithRetry(retries, retries + 1, retries + 1, e -> { throw new ExpectedException(e); }); }
-        );
+        ExpectedException ex = expectThrows(ExpectedException.class, () -> {
+            dotestBasicsWithRetry(retries, retries + 1, retries + 1, e -> { throw new ExpectedException(e); });
+        });
         assertThat(ex.getCause(), instanceOf(OpenSearchRejectedExecutionException.class));
     }
 
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/DeleteByQueryBasicTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/DeleteByQueryBasicTests.java
index 21bbb02fb147c..baf3c83bd0050 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/DeleteByQueryBasicTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/DeleteByQueryBasicTests.java
@@ -274,9 +274,9 @@ public void testDeleteByQueryOnReadOnlyAllowDeleteIndex() throws Exception {
                 InternalTestCluster internalTestCluster = internalCluster();
                 InternalClusterInfoService infoService = (InternalClusterInfoService) internalTestCluster.getInstance(
                     ClusterInfoService.class,
-                    internalTestCluster.getMasterName()
+                    internalTestCluster.getClusterManagerName()
                 );
-                ThreadPool threadPool = internalTestCluster.getInstance(ThreadPool.class, internalTestCluster.getMasterName());
+                ThreadPool threadPool = internalTestCluster.getInstance(ThreadPool.class, internalTestCluster.getClusterManagerName());
                 // Refresh the cluster info after a random delay to check the disk threshold and release the block on the index
                 threadPool.schedule(infoService::refresh, TimeValue.timeValueMillis(randomIntBetween(1, 100)), ThreadPool.Names.MANAGEMENT);
                 // The delete by query request will be executed successfully because the block will be released
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteBuildRestClientTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteBuildRestClientTests.java
index bd2aae5b7a7ab..2e14df4628283 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteBuildRestClientTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteBuildRestClientTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.client.RestClient;
 import org.opensearch.client.RestClientBuilderTestCase;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.index.query.MatchAllQueryBuilder;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWhitelistTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWhitelistTests.java
index 8012b67253cb6..0546f505c58cd 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWhitelistTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWhitelistTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.net.UnknownHostException;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
index 8ce850a936557..7c2f0e2c52a0e 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
@@ -32,12 +32,9 @@
 
 package org.opensearch.index.reindex;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchSecurityException;
 import org.opensearch.OpenSearchStatusException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.search.SearchAction;
 import org.opensearch.action.support.ActionFilter;
@@ -46,13 +43,17 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.http.HttpInfo;
@@ -60,7 +61,6 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.rest.RestHeaderDefinition;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexMetadataTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexMetadataTests.java
index 291325a3d8a5b..82619f1c3959b 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexMetadataTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexMetadataTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.index.reindex.ScrollableHitSource.Hit;
 import org.opensearch.action.index.IndexRequest;
+import org.opensearch.index.reindex.ScrollableHitSource.Hit;
 
 /**
  * Index-by-search test for ttl, timestamp, and routing.
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexRestClientSslTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexRestClientSslTests.java
index eb19454d8d7e8..1123ae4623300 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexRestClientSslTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexRestClientSslTests.java
@@ -36,15 +36,16 @@
 import com.sun.net.httpserver.HttpsExchange;
 import com.sun.net.httpserver.HttpsParameters;
 import com.sun.net.httpserver.HttpsServer;
+
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
 import org.opensearch.client.RestClient;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.ssl.PemKeyConfig;
 import org.opensearch.common.ssl.PemTrustConfig;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.test.OpenSearchTestCase;
@@ -60,6 +61,7 @@
 import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509ExtendedKeyManager;
 import javax.net.ssl.X509ExtendedTrustManager;
+
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.nio.file.Path;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexScriptTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexScriptTests.java
index 85f0c3c24abee..1700a25330463 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexScriptTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexScriptTests.java
@@ -35,10 +35,11 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.script.ScriptService;
-import org.mockito.Mockito;
 
 import java.util.Map;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.Matchers.containsString;
 
 /**
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexSourceTargetValidationTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexSourceTargetValidationTests.java
index e3bd1c1cba4a6..026017298fc5b 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexSourceTargetValidationTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexSourceTargetValidationTests.java
@@ -44,12 +44,12 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.SystemIndices;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.indices.SystemIndices;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashMap;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/RestReindexActionTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/RestReindexActionTests.java
index aa8221b045d3f..19859fea86bd6 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/RestReindexActionTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/RestReindexActionTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.test.rest.RestActionTestCase;
 import org.junit.Before;
@@ -88,14 +88,14 @@ public void testPipelineQueryParameterIsError() throws IOException {
     public void testSetScrollTimeout() throws IOException {
         {
             FakeRestRequest.Builder requestBuilder = new FakeRestRequest.Builder(xContentRegistry());
-            requestBuilder.withContent(new BytesArray("{}"), XContentType.JSON);
+            requestBuilder.withContent(new BytesArray("{}"), MediaTypeRegistry.JSON);
             ReindexRequest request = action.buildRequest(requestBuilder.build(), new NamedWriteableRegistry(Collections.emptyList()));
             assertEquals(AbstractBulkByScrollRequest.DEFAULT_SCROLL_TIMEOUT, request.getScrollTime());
         }
         {
             FakeRestRequest.Builder requestBuilder = new FakeRestRequest.Builder(xContentRegistry());
             requestBuilder.withParams(singletonMap("scroll", "10m"));
-            requestBuilder.withContent(new BytesArray("{}"), XContentType.JSON);
+            requestBuilder.withContent(new BytesArray("{}"), MediaTypeRegistry.JSON);
             ReindexRequest request = action.buildRequest(requestBuilder.build(), new NamedWriteableRegistry(Collections.emptyList()));
             assertEquals("10m", request.getScrollTime().toString());
         }
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/RethrottleTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/RethrottleTests.java
index 6bedd59515e45..c48f55a4ab08d 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/RethrottleTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/RethrottleTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionFuture;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.TaskGroup;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.tasks.TaskId;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/RetryTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/RetryTests.java
index 124670dba9510..84b9a22d90680 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/RetryTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/RetryTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.bulk.BackoffPolicy;
@@ -40,10 +39,11 @@
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.bulk.Retry;
 import org.opensearch.client.Client;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
@@ -118,18 +118,18 @@ public void testReindex() throws Exception {
     public void testReindexFromRemote() throws Exception {
         Function<Client, AbstractBulkByScrollRequestBuilder<?, ?>> function = client -> {
             /*
-             * Use the master node for the reindex from remote because that node
+             * Use the cluster-manager node for the reindex from remote because that node
              * doesn't have a copy of the data on it.
              */
-            NodeInfo masterNode = null;
+            NodeInfo clusterManagerNode = null;
             for (NodeInfo candidate : client.admin().cluster().prepareNodesInfo().get().getNodes()) {
-                if (candidate.getNode().isMasterNode()) {
-                    masterNode = candidate;
+                if (candidate.getNode().isClusterManagerNode()) {
+                    clusterManagerNode = candidate;
                 }
             }
-            assertNotNull(masterNode);
+            assertNotNull(clusterManagerNode);
 
-            TransportAddress address = masterNode.getInfo(HttpInfo.class).getAddress().publishAddress();
+            TransportAddress address = clusterManagerNode.getInfo(HttpInfo.class).getAddress().publishAddress();
             RemoteInfo remote = new RemoteInfo(
                 "http",
                 address.getAddress(),
@@ -206,7 +206,7 @@ private void testCase(
         assertFalse(initialBulkResponse.buildFailureMessage(), initialBulkResponse.hasFailures());
         client().admin().indices().prepareRefresh("source").get();
 
-        AbstractBulkByScrollRequestBuilder<?, ?> builder = request.apply(internalCluster().masterClient());
+        AbstractBulkByScrollRequestBuilder<?, ?> builder = request.apply(internalCluster().clusterManagerClient());
         // Make sure we use more than one batch so we have to scroll
         builder.source().setSize(DOC_COUNT / randomIntBetween(2, 10));
 
@@ -262,8 +262,8 @@ private CyclicBarrier blockExecutor(String name, String node) throws Exception {
      */
     private BulkByScrollTask.Status taskStatus(String action) {
         /*
-         * We always use the master client because we always start the test requests on the
-         * master. We do this simply to make sure that the test request is not started on the
+         * We always use the cluster-manager client because we always start the test requests on the
+         * cluster-manager. We do this simply to make sure that the test request is not started on the
          * node who's queue we're manipulating.
          */
         ListTasksResponse response = client().admin().cluster().prepareListTasks().setActions(action).setDetailed(true).get();
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/RoundTripTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/RoundTripTests.java
index 6239946852cf8..811620837d978 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/RoundTripTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/RoundTripTests.java
@@ -33,16 +33,16 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -50,8 +50,8 @@
 import java.util.HashMap;
 import java.util.Map;
 
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.opensearch.common.unit.TimeValue.parseTimeValue;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 /**
  * Round trip tests for all {@link Writeable} things declared in this plugin.
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/TransportRethrottleActionTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/TransportRethrottleActionTests.java
index a9e1a59b7e443..44b95244c9507 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/TransportRethrottleActionTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/TransportRethrottleActionTests.java
@@ -32,31 +32,32 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.client.Client;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matcher;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Consumer;
 
+import org.mockito.ArgumentCaptor;
+
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.hasToString;
 import static org.hamcrest.Matchers.theInstance;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.atMost;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
@@ -131,7 +132,8 @@ public void testRethrottleSuccessfulResponse() {
                     true,
                     false,
                     new TaskId("test", task.getId()),
-                    Collections.emptyMap()
+                    Collections.emptyMap(),
+                    null
                 )
             );
             sliceStatuses.add(new BulkByScrollTask.StatusOrException(status));
@@ -167,7 +169,8 @@ public void testRethrottleWithSomeSucceeded() {
                     true,
                     false,
                     new TaskId("test", task.getId()),
-                    Collections.emptyMap()
+                    Collections.emptyMap(),
+                    null
                 )
             );
             sliceStatuses.add(new BulkByScrollTask.StatusOrException(status));
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/UpdateByQueryWhileModifyingTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/UpdateByQueryWhileModifyingTests.java
index f203625dcfc44..b0fe9e55d3ba2 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/UpdateByQueryWhileModifyingTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/UpdateByQueryWhileModifyingTests.java
@@ -40,10 +40,10 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.hamcrest.Matchers.either;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 /**
  * Mutates a document while update-by-query-ing it and asserts that the mutation
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteInfoTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteInfoTests.java
index 91558963d4343..640a09c33b3a6 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteInfoTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteInfoTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.reindex.remote;
 
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.index.reindex.RemoteInfo;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteRequestBuildersTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteRequestBuildersTests.java
index c349bc54bcbd9..e3fbac9958df8 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteRequestBuildersTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteRequestBuildersTests.java
@@ -37,10 +37,10 @@
 import org.opensearch.Version;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.client.Request;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteResponseParsersTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteResponseParsersTests.java
index a6b0b0a67fc89..2a082e496b9e2 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteResponseParsersTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteResponseParsersTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.index.reindex.remote;
 
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.reindex.ScrollableHitSource;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSourceTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSourceTests.java
index 337bc67796f8e..aabd1100859d7 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSourceTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/remote/RemoteScrollableHitSourceTests.java
@@ -57,27 +57,25 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.client.HeapBufferedAsyncResponseConsumer;
 import org.opensearch.client.RestClient;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.index.reindex.RejectAwareActionListener;
 import org.opensearch.index.reindex.ScrollableHitSource;
 import org.opensearch.index.reindex.ScrollableHitSource.Response;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.After;
 import org.junit.Before;
-import org.mockito.invocation.InvocationOnMock;
-import org.mockito.stubbing.Answer;
 
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -92,6 +90,9 @@
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.common.unit.TimeValue.timeValueMinutes;
 import static org.hamcrest.Matchers.empty;
diff --git a/modules/reindex/src/test/resources/responses/failure_with_status.json b/modules/reindex/src/test/resources/responses/failure_with_status.json
index 314de37a6793e..f9de958a571b3 100644
--- a/modules/reindex/src/test/resources/responses/failure_with_status.json
+++ b/modules/reindex/src/test/resources/responses/failure_with_status.json
@@ -16,7 +16,6 @@
     "max_score": 0.0,
     "hits": [ {
       "_index": "test",
-      "_type": "test",
       "_id": "10000",
       "_version": 1,
       "_score": 0.0,
diff --git a/modules/reindex/src/test/resources/responses/rejection.json b/modules/reindex/src/test/resources/responses/rejection.json
index 0cc48bfca4fb5..e99cf02ee8023 100644
--- a/modules/reindex/src/test/resources/responses/rejection.json
+++ b/modules/reindex/src/test/resources/responses/rejection.json
@@ -21,7 +21,6 @@
     "max_score" : null,
     "hits" : [ {
       "_index" : "test",
-      "_type" : "test",
       "_id" : "AVToMiC250DjIiBO3yJ_",
       "_version" : 1,
       "_score" : null,
diff --git a/modules/reindex/src/test/resources/responses/scroll_fully_loaded.json b/modules/reindex/src/test/resources/responses/scroll_fully_loaded.json
index a2c1be34e5ccd..7a6b1ff748b92 100644
--- a/modules/reindex/src/test/resources/responses/scroll_fully_loaded.json
+++ b/modules/reindex/src/test/resources/responses/scroll_fully_loaded.json
@@ -13,7 +13,6 @@
     "max_score" : null,
     "hits" : [ {
       "_index" : "test",
-      "_type" : "test",
       "_id" : "AVToMiDL50DjIiBO3yKA",
       "_version" : 1,
       "_score" : null,
diff --git a/modules/reindex/src/test/resources/responses/scroll_fully_loaded_1_7.json b/modules/reindex/src/test/resources/responses/scroll_fully_loaded_1_7.json
index f8bebddecf3cf..2f5456704a6f0 100644
--- a/modules/reindex/src/test/resources/responses/scroll_fully_loaded_1_7.json
+++ b/modules/reindex/src/test/resources/responses/scroll_fully_loaded_1_7.json
@@ -13,7 +13,6 @@
     "max_score" : null,
     "hits" : [ {
       "_index" : "test",
-      "_type" : "test",
       "_id" : "AVToMiDL50DjIiBO3yKA",
       "_version" : 1,
       "_score" : null,
diff --git a/modules/reindex/src/test/resources/responses/scroll_ok.json b/modules/reindex/src/test/resources/responses/scroll_ok.json
index 5cdc4a400cbf0..ea6b473ed3e0e 100644
--- a/modules/reindex/src/test/resources/responses/scroll_ok.json
+++ b/modules/reindex/src/test/resources/responses/scroll_ok.json
@@ -13,7 +13,6 @@
     "max_score" : null,
     "hits" : [ {
       "_index" : "test",
-      "_type" : "test",
       "_id" : "AVToMiDL50DjIiBO3yKA",
       "_version" : 1,
       "_score" : null,
diff --git a/modules/reindex/src/test/resources/responses/start_ok.json b/modules/reindex/src/test/resources/responses/start_ok.json
index a2988341f8caf..97ef80f2dac06 100644
--- a/modules/reindex/src/test/resources/responses/start_ok.json
+++ b/modules/reindex/src/test/resources/responses/start_ok.json
@@ -12,7 +12,6 @@
     "max_score" : null,
     "hits" : [ {
       "_index" : "test",
-      "_type" : "test",
       "_id" : "AVToMiC250DjIiBO3yJ_",
       "_version" : 1,
       "_score" : null,
diff --git a/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/90_remote.yml b/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/90_remote.yml
index ac8d0730ff283..7d43a54987225 100644
--- a/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/90_remote.yml
+++ b/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/90_remote.yml
@@ -7,15 +7,15 @@
         body:    { "text": "test" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -68,15 +68,15 @@
   - do:
       indices.refresh: {}
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -118,15 +118,15 @@
         routing: foo
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -169,15 +169,15 @@
         body:    { "text": "test" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -236,15 +236,15 @@
         body:    { "text": "test" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -302,15 +302,15 @@
         body:    { "text": "test" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -358,15 +358,15 @@
         body:    { "text": "test" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       catch: /query malformed, no start_object after query name/
       reindex:
@@ -390,14 +390,12 @@
         refresh: true
 
   - do:
-      # sometimes IIS is listening on port 0. In that case we fail in other ways and this test isn't useful.
-      # make sure to stop any local webservers if running this test locally otherwise an s_s_l handshake exception may occur
       catch: /connect_exception|IIS Windows Server/
       reindex:
         body:
           source:
             remote:
-              host: http://127.0.0.1:0
+              host: http://127.0.0.1:54321
             index: source
           dest:
             index: dest
@@ -411,15 +409,15 @@
         body:    { "text": "test", "filtered": "removed" }
         refresh: true
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
@@ -480,15 +478,15 @@
       indices.refresh: {}
 
 
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         requests_per_second: .00000001 # About 9.5 years to complete the request
diff --git a/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/95_parent_join.yml b/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/95_parent_join.yml
index b36593b4b962c..a3c2e0505bda6 100644
--- a/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/95_parent_join.yml
+++ b/modules/reindex/src/yamlRestTest/resources/rest-api-spec/test/reindex/95_parent_join.yml
@@ -88,15 +88,15 @@ setup:
 
 ---
 "Reindex from remote with parent join field":
-  # Fetch the http host. We use the host of the master because we know there will always be a master.
+  # Fetch the http host. We use the host of the cluster-manager because we know there will always be a cluster-manager.
   - do:
       cluster.state: {}
-  - set: { master_node: master }
+  - set: { cluster_manager_node: cluster_manager }
   - do:
       nodes.info:
         metric: [ http ]
-  - is_true: nodes.$master.http.publish_address
-  - set: {nodes.$master.http.publish_address: host}
+  - is_true: nodes.$cluster_manager.http.publish_address
+  - set: {nodes.$cluster_manager.http.publish_address: host}
   - do:
       reindex:
         refresh: true
diff --git a/modules/repository-s3/licenses/commons-logging-1.2.jar.sha1 b/modules/repository-s3/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/modules/repository-s3/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/modules/repository-url/build.gradle b/modules/repository-url/build.gradle
index 24742416de6f2..702f0e9bb0f8b 100644
--- a/modules/repository-url/build.gradle
+++ b/modules/repository-url/build.gradle
@@ -75,4 +75,3 @@ testClusters.all {
     "http://snapshot.test*,http://${urlFixture.addressAndPort}"
   }, PropertyNormalization.IGNORE_VALUE
 }
-
diff --git a/modules/repository-url/src/internalClusterTest/java/org/opensearch/repositories/url/URLSnapshotRestoreIT.java b/modules/repository-url/src/internalClusterTest/java/org/opensearch/repositories/url/URLSnapshotRestoreIT.java
index aa274549f3a9b..e073db7276119 100644
--- a/modules/repository-url/src/internalClusterTest/java/org/opensearch/repositories/url/URLSnapshotRestoreIT.java
+++ b/modules/repository-url/src/internalClusterTest/java/org/opensearch/repositories/url/URLSnapshotRestoreIT.java
@@ -38,7 +38,7 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.plugin.repository.url.URLRepositoryPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.fs.FsRepository;
diff --git a/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobContainer.java b/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobContainer.java
index 1f966be98bdf7..b13a4d5a39a5b 100644
--- a/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobContainer.java
+++ b/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobContainer.java
@@ -83,12 +83,20 @@ public URL url() {
     }
 
     /**
-     * This operation is not supported by URLBlobContainer
+     * Tests whether a blob with the given blob name exists in the container.
+     *
+     * @param   blobName
+     *          The name of the blob whose existence is to be determined.
+     * @return  {@code true} if a blob exists in the {@link BlobContainer} with the given name, and {@code false} otherwise.
      */
     @Override
-    public boolean blobExists(String blobName) {
-        assert false : "should never be called for a read-only url repo";
-        throw new UnsupportedOperationException("URL repository doesn't support this operation");
+    public boolean blobExists(String blobName) throws IOException {
+        try {
+            readBlob(blobName);
+            return true;
+        } catch (FileNotFoundException e) {
+            return false;
+        }
     }
 
     /**
diff --git a/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobStore.java b/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobStore.java
index fbfbf5e006fee..0fad0cbe21033 100644
--- a/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobStore.java
+++ b/modules/repository-url/src/main/java/org/opensearch/common/blobstore/url/URLBlobStore.java
@@ -37,8 +37,8 @@
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.blobstore.BlobStoreException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.net.MalformedURLException;
 import java.net.URL;
diff --git a/modules/repository-url/src/main/java/org/opensearch/plugin/repository/url/URLRepositoryPlugin.java b/modules/repository-url/src/main/java/org/opensearch/plugin/repository/url/URLRepositoryPlugin.java
index d1b08d443805f..5b26008d70f46 100644
--- a/modules/repository-url/src/main/java/org/opensearch/plugin/repository/url/URLRepositoryPlugin.java
+++ b/modules/repository-url/src/main/java/org/opensearch/plugin/repository/url/URLRepositoryPlugin.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
diff --git a/modules/repository-url/src/main/java/org/opensearch/repositories/url/URLRepository.java b/modules/repository-url/src/main/java/org/opensearch/repositories/url/URLRepository.java
index 837a30555e127..4c8d8aab4532b 100644
--- a/modules/repository-url/src/main/java/org/opensearch/repositories/url/URLRepository.java
+++ b/modules/repository-url/src/main/java/org/opensearch/repositories/url/URLRepository.java
@@ -43,7 +43,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.util.URIPattern;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.RepositoryException;
@@ -113,7 +113,7 @@ public URLRepository(
         ClusterService clusterService,
         RecoverySettings recoverySettings
     ) {
-        super(metadata, false, namedXContentRegistry, clusterService, recoverySettings);
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings);
 
         if (URL_SETTING.exists(metadata.settings()) == false && REPOSITORIES_URL_SETTING.exists(environment.settings()) == false) {
             throw new RepositoryException(metadata.name(), "missing url");
diff --git a/modules/repository-url/src/test/java/org/opensearch/common/blobstore/url/URLBlobStoreTests.java b/modules/repository-url/src/test/java/org/opensearch/common/blobstore/url/URLBlobStoreTests.java
index 90b75f50b16ad..0b62304270052 100644
--- a/modules/repository-url/src/test/java/org/opensearch/common/blobstore/url/URLBlobStoreTests.java
+++ b/modules/repository-url/src/test/java/org/opensearch/common/blobstore/url/URLBlobStoreTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.blobstore.url;
 
 import com.sun.net.httpserver.HttpServer;
+
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
diff --git a/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLFixture.java b/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLFixture.java
index 04c2d249be635..b2dab1314f66d 100644
--- a/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLFixture.java
+++ b/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLFixture.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.repositories.url;
 
-import org.opensearch.test.fixture.AbstractHttpFixture;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.test.fixture.AbstractHttpFixture;
 
 import java.io.IOException;
 import java.nio.file.Files;
diff --git a/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLRepositoryTests.java b/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLRepositoryTests.java
index 30d1c81fc9e9f..7fdfa2d6b3346 100644
--- a/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLRepositoryTests.java
+++ b/modules/repository-url/src/test/java/org/opensearch/repositories/url/URLRepositoryTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.indices.recovery.RecoverySettings;
diff --git a/modules/repository-url/src/yamlRestTest/java/org/opensearch/repositories/url/RepositoryURLClientYamlTestSuiteIT.java b/modules/repository-url/src/yamlRestTest/java/org/opensearch/repositories/url/RepositoryURLClientYamlTestSuiteIT.java
index 3d0c09fb2288c..02c890b2a8ee4 100644
--- a/modules/repository-url/src/yamlRestTest/java/org/opensearch/repositories/url/RepositoryURLClientYamlTestSuiteIT.java
+++ b/modules/repository-url/src/yamlRestTest/java/org/opensearch/repositories/url/RepositoryURLClientYamlTestSuiteIT.java
@@ -34,19 +34,19 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.http.HttpEntity;
 import org.apache.http.entity.ContentType;
 import org.apache.http.nio.entity.NStringEntity;
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.fs.FsRepository;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 import org.junit.Before;
@@ -144,7 +144,7 @@ private static HttpEntity buildRepositorySettings(final String type, final Setti
                 builder.endObject();
             }
             builder.endObject();
-            return new NStringEntity(Strings.toString(builder), ContentType.APPLICATION_JSON);
+            return new NStringEntity(builder.toString(), ContentType.APPLICATION_JSON);
         }
     }
 }
diff --git a/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/10_basic.yml b/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/10_basic.yml
index b932f0d53caad..0c7aed0ae7103 100644
--- a/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/10_basic.yml
+++ b/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/10_basic.yml
@@ -102,13 +102,13 @@ teardown:
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains: { nodes.$master.modules: { name: repository-url } }
+    - contains: { nodes.$cluster_manager.modules: { name: repository-url } }
 
 ---
 "Restore with repository-url using http://":
diff --git a/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/20_repository.yml b/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/20_repository.yml
index f40ad16bb4265..cc6b3b5ce1f33 100644
--- a/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/20_repository.yml
+++ b/modules/repository-url/src/yamlRestTest/resources/rest-api-spec/test/repository_url/20_repository.yml
@@ -27,6 +27,3 @@
           type: url
           settings:
             url: "http://snapshot.unknown"
-
-
-    
diff --git a/modules/search-pipeline-common/build.gradle b/modules/search-pipeline-common/build.gradle
new file mode 100644
index 0000000000000..657392d884e97
--- /dev/null
+++ b/modules/search-pipeline-common/build.gradle
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+apply plugin: 'opensearch.yaml-rest-test'
+apply plugin: 'opensearch.internal-cluster-test'
+
+opensearchplugin {
+  description 'Module for search pipeline processors that do not require additional security permissions or have large dependencies and resources'
+  classname 'org.opensearch.search.pipeline.common.SearchPipelineCommonModulePlugin'
+  extendedPlugins = ['lang-painless']
+}
+
+dependencies {
+  compileOnly project(':modules:lang-painless')
+}
+
+restResources {
+  restApi {
+    includeCore '_common', 'search_pipeline', 'cluster', 'indices', 'index', 'nodes',  'search'
+  }
+}
+
+
+thirdPartyAudit.ignoreMissingClasses(
+  // from log4j
+  'org.osgi.framework.AdaptPermission',
+  'org.osgi.framework.AdminPermission',
+  'org.osgi.framework.Bundle',
+  'org.osgi.framework.BundleActivator',
+  'org.osgi.framework.BundleContext',
+  'org.osgi.framework.BundleEvent',
+  'org.osgi.framework.SynchronousBundleListener',
+  'org.osgi.framework.wiring.BundleWire',
+  'org.osgi.framework.wiring.BundleWiring'
+)
diff --git a/modules/search-pipeline-common/src/internalClusterTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonIT.java b/modules/search-pipeline-common/src/internalClusterTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonIT.java
new file mode 100644
index 0000000000000..b8b0798812df1
--- /dev/null
+++ b/modules/search-pipeline-common/src/internalClusterTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonIT.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.action.admin.indices.refresh.RefreshRequest;
+import org.opensearch.action.admin.indices.refresh.RefreshResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.query.MatchAllQueryBuilder;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class SearchPipelineCommonIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return List.of(SearchPipelineCommonModulePlugin.class);
+    }
+
+    public void testFilterQuery() {
+        // Create a pipeline with a filter_query processor.
+        String pipelineName = "foo";
+        PutSearchPipelineRequest putSearchPipelineRequest = new PutSearchPipelineRequest(
+            pipelineName,
+            new BytesArray(
+                "{"
+                    + "\"request_processors\": ["
+                    + "{"
+                    + "\"filter_query\" : {"
+                    + "\"query\": {"
+                    + "\"term\" : {"
+                    + "\"field\" : \"value\""
+                    + "}"
+                    + "}"
+                    + "}"
+                    + "}"
+                    + "]"
+                    + "}"
+            ),
+            MediaTypeRegistry.JSON
+        );
+        AcknowledgedResponse ackRsp = client().admin().cluster().putSearchPipeline(putSearchPipelineRequest).actionGet();
+        assertTrue(ackRsp.isAcknowledged());
+
+        // Index some documents.
+        String indexName = "myindex";
+        IndexRequest doc1 = new IndexRequest(indexName).id("doc1").source(Map.of("field", "value"));
+        IndexRequest doc2 = new IndexRequest(indexName).id("doc2").source(Map.of("field", "something else"));
+
+        IndexResponse ir = client().index(doc1).actionGet();
+        assertSame(RestStatus.CREATED, ir.status());
+        ir = client().index(doc2).actionGet();
+        assertSame(RestStatus.CREATED, ir.status());
+
+        // Refresh so the documents are visible to search.
+        RefreshResponse refRsp = client().admin().indices().refresh(new RefreshRequest(indexName)).actionGet();
+        assertSame(RestStatus.OK, refRsp.getStatus());
+
+        // Search without the pipeline. Should see both documents.
+        SearchRequest req = new SearchRequest(indexName).source(new SearchSourceBuilder().query(new MatchAllQueryBuilder()));
+        SearchResponse rsp = client().search(req).actionGet();
+        assertEquals(2, rsp.getHits().getTotalHits().value);
+
+        // Search with the pipeline. Should only see document with "field":"value".
+        req.pipeline(pipelineName);
+        rsp = client().search(req).actionGet();
+        assertEquals(1, rsp.getHits().getTotalHits().value);
+
+        // Clean up.
+        ackRsp = client().admin().cluster().deleteSearchPipeline(new DeleteSearchPipelineRequest(pipelineName)).actionGet();
+        assertTrue(ackRsp.isAcknowledged());
+        ackRsp = client().admin().indices().delete(new DeleteIndexRequest(indexName)).actionGet();
+        assertTrue(ackRsp.isAcknowledged());
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessor.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessor.java
new file mode 100644
index 0000000000000..3d04d6d5ed1e3
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessor.java
@@ -0,0 +1,124 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.query.BoolQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.ingest.ConfigurationUtils;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.pipeline.AbstractProcessor;
+import org.opensearch.search.pipeline.Processor;
+import org.opensearch.search.pipeline.SearchRequestProcessor;
+
+import java.io.InputStream;
+import java.util.Map;
+
+import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
+
+/**
+ * This is a {@link SearchRequestProcessor} that replaces the incoming query with a BooleanQuery
+ * that MUST match the incoming query with a FILTER clause based on the configured query.
+ */
+public class FilterQueryRequestProcessor extends AbstractProcessor implements SearchRequestProcessor {
+    /**
+     * Key to reference this processor type from a search pipeline.
+     */
+    public static final String TYPE = "filter_query";
+
+    final QueryBuilder filterQuery;
+
+    /**
+     * Returns the type of the processor.
+     *
+     * @return The processor type.
+     */
+    @Override
+    public String getType() {
+        return TYPE;
+    }
+
+    /**
+     * Constructor that takes a filter query.
+     *
+     * @param tag            processor tag
+     * @param description    processor description
+     * @param ignoreFailure  option to ignore failure
+     * @param filterQuery the query that will be added as a filter to incoming queries
+     */
+    FilterQueryRequestProcessor(String tag, String description, boolean ignoreFailure, QueryBuilder filterQuery) {
+        super(tag, description, ignoreFailure);
+        this.filterQuery = filterQuery;
+    }
+
+    /**
+     * Modifies the search request by adding a filtered query to the existing query, if any, and sets it as the new query
+     * in the search request's SearchSourceBuilder.
+     *
+     * @param request The search request to be processed.
+     * @return The modified search request.
+     * @throws Exception if an error occurs while processing the request.
+     */
+    @Override
+    public SearchRequest processRequest(SearchRequest request) throws Exception {
+        QueryBuilder originalQuery = null;
+        if (request.source() != null) {
+            originalQuery = request.source().query();
+        }
+
+        BoolQueryBuilder filteredQuery = new BoolQueryBuilder().filter(filterQuery);
+        if (originalQuery != null) {
+            filteredQuery.must(originalQuery);
+        }
+        if (request.source() == null) {
+            request.source(new SearchSourceBuilder());
+        }
+        request.source().query(filteredQuery);
+        return request;
+    }
+
+    static class Factory implements Processor.Factory<SearchRequestProcessor> {
+        private static final String QUERY_KEY = "query";
+        private final NamedXContentRegistry namedXContentRegistry;
+
+        Factory(NamedXContentRegistry namedXContentRegistry) {
+            this.namedXContentRegistry = namedXContentRegistry;
+        }
+
+        @Override
+        public FilterQueryRequestProcessor create(
+            Map<String, Processor.Factory<SearchRequestProcessor>> processorFactories,
+            String tag,
+            String description,
+            boolean ignoreFailure,
+            Map<String, Object> config,
+            PipelineContext pipelineContext
+        ) throws Exception {
+            Map<String, Object> query = ConfigurationUtils.readOptionalMap(TYPE, tag, config, QUERY_KEY);
+            if (query == null) {
+                throw new IllegalArgumentException("Did not specify the " + QUERY_KEY + " property in processor of type " + TYPE);
+            }
+            try (
+                XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(query);
+                InputStream stream = BytesReference.bytes(builder).streamInput();
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
+                    .createParser(namedXContentRegistry, LoggingDeprecationHandler.INSTANCE, stream)
+            ) {
+                return new FilterQueryRequestProcessor(tag, description, ignoreFailure, parseInnerQueryBuilder(parser));
+            }
+        }
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessor.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessor.java
new file mode 100644
index 0000000000000..212fe844d97a1
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessor.java
@@ -0,0 +1,162 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.document.DocumentField;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.ingest.ConfigurationUtils;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.pipeline.AbstractProcessor;
+import org.opensearch.search.pipeline.Processor;
+import org.opensearch.search.pipeline.SearchRequestProcessor;
+import org.opensearch.search.pipeline.SearchResponseProcessor;
+
+import java.util.Map;
+
+/**
+ * This is a {@link SearchRequestProcessor} that renames a field before returning the search response
+ */
+public class RenameFieldResponseProcessor extends AbstractProcessor implements SearchResponseProcessor {
+
+    private final String oldField;
+    private final String newField;
+    private final boolean ignoreMissing;
+
+    /**
+     * Key to reference this processor type from a search pipeline.
+     */
+    public static final String TYPE = "rename_field";
+
+    /**
+     * Constructor that takes a target field to rename and the new name
+     *
+     * @param tag            processor tag
+     * @param description    processor description
+     * @param ignoreFailure  option to ignore failure
+     * @param oldField       name of field to be renamed
+     * @param newField       name of field that will replace the old field
+     * @param ignoreMissing if true, do not throw error if oldField does not exist within search response
+     */
+    public RenameFieldResponseProcessor(
+        String tag,
+        String description,
+        boolean ignoreFailure,
+        String oldField,
+        String newField,
+        boolean ignoreMissing
+    ) {
+        super(tag, description, ignoreFailure);
+        this.oldField = oldField;
+        this.newField = newField;
+        this.ignoreMissing = ignoreMissing;
+    }
+
+    @Override
+    public String getType() {
+        return TYPE;
+    }
+
+    /**
+     * Getter function for oldField
+     * @return oldField
+     */
+    public String getOldField() {
+        return oldField;
+    }
+
+    /**
+     * Getter function for newField
+     * @return newField
+     */
+    public String getNewField() {
+        return newField;
+    }
+
+    /**
+     * Getter function for ignoreMissing
+     * @return ignoreMissing
+     */
+    public boolean isIgnoreMissing() {
+        return ignoreMissing;
+    }
+
+    @Override
+    public SearchResponse processResponse(SearchRequest request, SearchResponse response) throws Exception {
+        boolean foundField = false;
+
+        SearchHit[] hits = response.getHits().getHits();
+        for (SearchHit hit : hits) {
+            Map<String, DocumentField> fields = hit.getFields();
+            if (fields.containsKey(oldField)) {
+                foundField = true;
+                DocumentField old = hit.removeDocumentField(oldField);
+                DocumentField newDocField = new DocumentField(newField, old.getValues());
+                hit.setDocumentField(newField, newDocField);
+            }
+
+            if (hit.hasSource()) {
+                BytesReference sourceRef = hit.getSourceRef();
+                Tuple<? extends MediaType, Map<String, Object>> typeAndSourceMap = XContentHelper.convertToMap(
+                    sourceRef,
+                    false,
+                    (MediaType) null
+                );
+
+                Map<String, Object> sourceAsMap = typeAndSourceMap.v2();
+                if (sourceAsMap.containsKey(oldField)) {
+                    foundField = true;
+                    Object val = sourceAsMap.remove(oldField);
+                    sourceAsMap.put(newField, val);
+
+                    XContentBuilder builder = XContentBuilder.builder(typeAndSourceMap.v1().xContent());
+                    builder.map(sourceAsMap);
+                    hit.sourceRef(BytesReference.bytes(builder));
+                }
+            }
+
+            if (!foundField && !ignoreMissing) {
+                throw new IllegalArgumentException("Document with id " + hit.getId() + " is missing field " + oldField);
+            }
+        }
+
+        return response;
+    }
+
+    /**
+     * This is a factor that creates the RenameResponseProcessor
+     */
+    public static final class Factory implements Processor.Factory<SearchResponseProcessor> {
+
+        /**
+         * Constructor for factory
+         */
+        Factory() {}
+
+        @Override
+        public RenameFieldResponseProcessor create(
+            Map<String, Processor.Factory<SearchResponseProcessor>> processorFactories,
+            String tag,
+            String description,
+            boolean ignoreFailure,
+            Map<String, Object> config,
+            PipelineContext pipelineContext
+        ) throws Exception {
+            String oldField = ConfigurationUtils.readStringProperty(TYPE, tag, config, "field");
+            String newField = ConfigurationUtils.readStringProperty(TYPE, tag, config, "target_field");
+            boolean ignoreMissing = ConfigurationUtils.readBooleanProperty(TYPE, tag, config, "ignore_missing", false);
+            return new RenameFieldResponseProcessor(tag, description, ignoreFailure, oldField, newField, ignoreMissing);
+        }
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/ScriptRequestProcessor.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/ScriptRequestProcessor.java
new file mode 100644
index 0000000000000..90f71fd1754e4
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/ScriptRequestProcessor.java
@@ -0,0 +1,183 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptException;
+import org.opensearch.script.ScriptService;
+import org.opensearch.script.ScriptType;
+import org.opensearch.script.SearchScript;
+import org.opensearch.search.pipeline.AbstractProcessor;
+import org.opensearch.search.pipeline.Processor;
+import org.opensearch.search.pipeline.SearchRequestProcessor;
+import org.opensearch.search.pipeline.common.helpers.SearchRequestMap;
+
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.ingest.ConfigurationUtils.newConfigurationException;
+
+/**
+ * Processor that evaluates a script with a search request in its context
+ * and then returns the modified search request.
+ */
+public final class ScriptRequestProcessor extends AbstractProcessor implements SearchRequestProcessor {
+    /**
+     * Key to reference this processor type from a search pipeline.
+     */
+    public static final String TYPE = "script";
+
+    private final Script script;
+    private final ScriptService scriptService;
+    private final SearchScript precompiledSearchScript;
+
+    /**
+     * Processor that evaluates a script with a search request in its context
+     *
+     * @param tag The processor's tag.
+     * @param description The processor's description.
+     * @param ignoreFailure The option to ignore failure
+     * @param script The {@link Script} to execute.
+     * @param precompiledSearchScript The {@link Script} precompiled
+     * @param scriptService The {@link ScriptService} used to execute the script.
+     */
+    ScriptRequestProcessor(
+        String tag,
+        String description,
+        boolean ignoreFailure,
+        Script script,
+        @Nullable SearchScript precompiledSearchScript,
+        ScriptService scriptService
+    ) {
+        super(tag, description, ignoreFailure);
+        this.script = script;
+        this.precompiledSearchScript = precompiledSearchScript;
+        this.scriptService = scriptService;
+    }
+
+    /**
+     * Executes the script with the search request in context.
+     *
+     * @param request The search request passed into the script context.
+     * @return The modified search request.
+     * @throws Exception if an error occurs while processing the request.
+     */
+    @Override
+    public SearchRequest processRequest(SearchRequest request) throws Exception {
+        // assert request is not null and source is not null
+        if (request == null || request.source() == null) {
+            throw new IllegalArgumentException("search request must not be null");
+        }
+        final SearchScript searchScript;
+        if (precompiledSearchScript == null) {
+            SearchScript.Factory factory = scriptService.compile(script, SearchScript.CONTEXT);
+            searchScript = factory.newInstance(script.getParams());
+        } else {
+            searchScript = precompiledSearchScript;
+        }
+        // execute the script with the search request in context
+        searchScript.execute(Map.of("_source", new SearchRequestMap(request)));
+        return request;
+    }
+
+    /**
+     * Returns the type of the processor.
+     *
+     * @return The processor type.
+     */
+    @Override
+    public String getType() {
+        return TYPE;
+    }
+
+    /**
+     * Returns the script used by the processor.
+     *
+     * @return The script.
+     */
+    Script getScript() {
+        return script;
+    }
+
+    /**
+     * Returns the precompiled search script used by the processor.
+     *
+     * @return The precompiled search script.
+     */
+    SearchScript getPrecompiledSearchScript() {
+        return precompiledSearchScript;
+    }
+
+    /**
+     * Factory class for creating {@link ScriptRequestProcessor}.
+     */
+    public static final class Factory implements Processor.Factory<SearchRequestProcessor> {
+        private static final List<String> SCRIPT_CONFIG_KEYS = List.of("id", "source", "inline", "lang", "params", "options");
+
+        private final ScriptService scriptService;
+
+        /**
+         * Constructs a new Factory instance with the specified {@link ScriptService}.
+         *
+         * @param scriptService The {@link ScriptService} used to execute scripts.
+         */
+        public Factory(ScriptService scriptService) {
+            this.scriptService = scriptService;
+        }
+
+        @Override
+        public ScriptRequestProcessor create(
+            Map<String, Processor.Factory<SearchRequestProcessor>> registry,
+            String processorTag,
+            String description,
+            boolean ignoreFailure,
+            Map<String, Object> config,
+            PipelineContext pipelineContext
+        ) throws Exception {
+            Map<String, Object> scriptConfig = new HashMap<>();
+            for (String key : SCRIPT_CONFIG_KEYS) {
+                Object val = config.remove(key);
+                if (val != null) {
+                    scriptConfig.put(key, val);
+                }
+            }
+            try (
+                XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(scriptConfig);
+                InputStream stream = BytesReference.bytes(builder).streamInput();
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
+                    .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
+            ) {
+                Script script = Script.parse(parser);
+
+                // verify script is able to be compiled before successfully creating processor.
+                SearchScript searchScript = null;
+                try {
+                    final SearchScript.Factory factory = scriptService.compile(script, SearchScript.CONTEXT);
+                    if (ScriptType.INLINE.equals(script.getType())) {
+                        searchScript = factory.newInstance(script.getParams());
+                    }
+                } catch (ScriptException e) {
+                    throw newConfigurationException(TYPE, processorTag, null, e);
+                }
+                return new ScriptRequestProcessor(processorTag, description, ignoreFailure, script, searchScript, scriptService);
+            }
+        }
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/SearchPipelineCommonModulePlugin.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/SearchPipelineCommonModulePlugin.java
new file mode 100644
index 0000000000000..49681b80fdead
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/SearchPipelineCommonModulePlugin.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.SearchPipelinePlugin;
+import org.opensearch.search.pipeline.Processor;
+import org.opensearch.search.pipeline.SearchRequestProcessor;
+import org.opensearch.search.pipeline.SearchResponseProcessor;
+
+import java.util.Map;
+
+/**
+ * Plugin providing common search request/response processors for use in search pipelines.
+ */
+public class SearchPipelineCommonModulePlugin extends Plugin implements SearchPipelinePlugin {
+
+    /**
+     * No constructor needed, but build complains if we don't have a constructor with JavaDoc.
+     */
+    public SearchPipelineCommonModulePlugin() {}
+
+    /**
+     * Returns a map of processor factories.
+     *
+     * @param parameters The parameters required for creating the processor factories.
+     * @return A map of processor factories, where the keys are the processor types and the values are the corresponding factory instances.
+     */
+    @Override
+    public Map<String, Processor.Factory<SearchRequestProcessor>> getRequestProcessors(Parameters parameters) {
+        return Map.of(
+            FilterQueryRequestProcessor.TYPE,
+            new FilterQueryRequestProcessor.Factory(parameters.namedXContentRegistry),
+            ScriptRequestProcessor.TYPE,
+            new ScriptRequestProcessor.Factory(parameters.scriptService)
+        );
+    }
+
+    @Override
+    public Map<String, Processor.Factory<SearchResponseProcessor>> getResponseProcessors(Parameters parameters) {
+        return Map.of(RenameFieldResponseProcessor.TYPE, new RenameFieldResponseProcessor.Factory());
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMap.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMap.java
new file mode 100644
index 0000000000000..7af3ac66be146
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMap.java
@@ -0,0 +1,395 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common.helpers;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.search.builder.SearchSourceBuilder;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+/**
+ * A custom implementation of {@link Map} that provides access to the properties of a {@link SearchRequest}'s
+ * {@link SearchSourceBuilder}. The class allows retrieving and modifying specific properties of the search request.
+ */
+public class SearchRequestMap implements Map<String, Object> {
+    private static final String UNSUPPORTED_OP_ERR = " Method not supported in Search pipeline script";
+
+    private final SearchSourceBuilder source;
+
+    /**
+     * Constructs a new instance of the {@link SearchRequestMap} with the provided {@link SearchRequest}.
+     *
+     * @param searchRequest The SearchRequest containing the SearchSourceBuilder to be accessed.
+     */
+    public SearchRequestMap(SearchRequest searchRequest) {
+        source = searchRequest.source();
+    }
+
+    /**
+     * Retrieves the number of properties in the SearchSourceBuilder.
+     *
+     * @return The number of properties in the SearchSourceBuilder.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public int size() {
+        throw new UnsupportedOperationException("size" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Checks if the SearchSourceBuilder is empty.
+     *
+     * @return {@code true} if the SearchSourceBuilder is empty, {@code false} otherwise.
+     */
+    @Override
+    public boolean isEmpty() {
+        return source == null;
+    }
+
+    /**
+     * Checks if the SearchSourceBuilder contains the specified property.
+     *
+     * @param key The property to check for.
+     * @return {@code true} if the SearchSourceBuilder contains the specified property, {@code false} otherwise.
+     */
+    @Override
+    public boolean containsKey(Object key) {
+        return get(key) != null;
+    }
+
+    /**
+     * Checks if the SearchSourceBuilder contains the specified value.
+     *
+     * @param value The value to check for.
+     * @return {@code true} if the SearchSourceBuilder contains the specified value, {@code false} otherwise.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public boolean containsValue(Object value) {
+        throw new UnsupportedOperationException("containsValue" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Retrieves the value associated with the specified property from the SearchSourceBuilder.
+     *
+     * @param key The SearchSourceBuilder property whose value is to be retrieved.
+     * @return The value associated with the specified property or null if the property has not been initialized.
+     * @throws IllegalArgumentException if the property name is not a String.
+     * @throws SearchRequestMapProcessingException if the property is not supported.
+     */
+    @Override
+    public Object get(Object key) {
+        if (!(key instanceof String)) {
+            throw new IllegalArgumentException("key must be a String");
+        }
+        // This is the explicit implementation of fetch value from source
+        switch ((String) key) {
+            case "from":
+                return source.from();
+            case "size":
+                return source.size();
+            case "explain":
+                return source.explain();
+            case "version":
+                return source.version();
+            case "seq_no_primary_term":
+                return source.seqNoAndPrimaryTerm();
+            case "track_scores":
+                return source.trackScores();
+            case "track_total_hits":
+                return source.trackTotalHitsUpTo();
+            case "min_score":
+                return source.minScore();
+            case "terminate_after":
+                return source.terminateAfter();
+            case "profile":
+                return source.profile();
+            default:
+                throw new SearchRequestMapProcessingException("Unsupported key: " + key);
+        }
+    }
+
+    /**
+     * Sets the value for the specified property in the SearchSourceBuilder.
+     *
+     * @param key The property whose value is to be set.
+     * @param value The value to be set for the specified property.
+     * @return The original value associated with the property, or null if none existed.
+     * @throws IllegalArgumentException if the property is not a String.
+     * @throws SearchRequestMapProcessingException if the property is not supported or an error occurs during the setting.
+     */
+    @Override
+    public Object put(String key, Object value) {
+        Object originalValue = get(key);
+        try {
+            switch (key) {
+                case "from":
+                    source.from((Integer) value);
+                    break;
+                case "size":
+                    source.size((Integer) value);
+                    break;
+                case "explain":
+                    source.explain((Boolean) value);
+                    break;
+                case "version":
+                    source.version((Boolean) value);
+                    break;
+                case "seq_no_primary_term":
+                    source.seqNoAndPrimaryTerm((Boolean) value);
+                    break;
+                case "track_scores":
+                    source.trackScores((Boolean) value);
+                    break;
+                case "track_total_hits":
+                    source.trackTotalHitsUpTo((Integer) value);
+                    break;
+                case "min_score":
+                    source.minScore((Float) value);
+                    break;
+                case "terminate_after":
+                    source.terminateAfter((Integer) value);
+                    break;
+                case "profile":
+                    source.profile((Boolean) value);
+                    break;
+                case "stats": // Not modifying stats, sorts, docvalue_fields, etc. as they require more complex handling
+                case "sort":
+                case "timeout":
+                case "docvalue_fields":
+                case "indices_boost":
+                default:
+                    throw new SearchRequestMapProcessingException("Unsupported SearchRequest source property: " + key);
+            }
+        } catch (Exception e) {
+            throw new SearchRequestMapProcessingException("Error while setting value for SearchRequest source property: " + key, e);
+        }
+        return originalValue;
+    }
+
+    /**
+     * Removes the specified property from the SearchSourceBuilder.
+     *
+     * @param key The name of the property that will be removed.
+     * @return The value associated with the property before it was removed, or null if the property was not found.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object remove(Object key) {
+        throw new UnsupportedOperationException("remove" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Sets all the properties from the specified map to the SearchSourceBuilder.
+     *
+     * @param m The map containing the properties to be set.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public void putAll(Map<? extends String, ?> m) {
+        throw new UnsupportedOperationException("putAll" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Removes all properties from the SearchSourceBuilder.
+     *
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public void clear() {
+        throw new UnsupportedOperationException("clear" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Returns a set view of the property names in the SearchSourceBuilder.
+     *
+     * @return A set view of the property names in the SearchSourceBuilder.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Set<String> keySet() {
+        throw new UnsupportedOperationException("keySet" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Returns a collection view of the property values in the SearchSourceBuilder.
+     *
+     * @return A collection view of the property values in the SearchSourceBuilder.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Collection<Object> values() {
+        throw new UnsupportedOperationException("values" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Returns a set view of the properties in the SearchSourceBuilder.
+     *
+     * @return A set view of the properties in the SearchSourceBuilder.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Set<Entry<String, Object>> entrySet() {
+        throw new UnsupportedOperationException("entrySet" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Returns the value to which the specified property has, or the defaultValue if the property is not present in the
+     * SearchSourceBuilder.
+     *
+     * @param key The property whose associated value is to be returned.
+     * @param defaultValue The default value to be returned if the property is not present.
+     * @return The value to which the specified property has, or the defaultValue if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object getOrDefault(Object key, Object defaultValue) {
+        throw new UnsupportedOperationException("getOrDefault" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Performs the given action for each property in the SearchSourceBuilder until all properties have been processed or the
+     * action throws an exception
+     *
+     * @param action The action to be performed for each property.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public void forEach(BiConsumer<? super String, ? super Object> action) {
+        throw new UnsupportedOperationException("forEach" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Replaces each property's value with the result of invoking the given function on that property until all properties have
+     * been processed or the function throws an exception.
+     *
+     * @param function The function to apply to each property.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public void replaceAll(BiFunction<? super String, ? super Object, ?> function) {
+        throw new UnsupportedOperationException("replaceAll" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * If the specified property is not already associated with a value, associates it with the given value and returns null,
+     * else returns the current value.
+     *
+     * @param key The property whose value is to be set if absent.
+     * @param value The value to be associated with the specified property.
+     * @return The current value associated with the property, or null if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object putIfAbsent(String key, Object value) {
+        throw new UnsupportedOperationException("putIfAbsent" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Removes the property only if it has the given value.
+     *
+     * @param key The property to be removed.
+     * @param value The value expected to be associated with the property.
+     * @return {@code true} if the entry was removed, {@code false} otherwise.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public boolean remove(Object key, Object value) {
+        throw new UnsupportedOperationException("remove" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Replaces the specified property only if it has the given value.
+     *
+     * @param key The property to be replaced.
+     * @param oldValue The value expected to be associated with the property.
+     * @param newValue The value to be associated with the property.
+     * @return {@code true} if the property was replaced, {@code false} otherwise.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public boolean replace(String key, Object oldValue, Object newValue) {
+        throw new UnsupportedOperationException("replace" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * Replaces the specified property only if it has the given value.
+     *
+     * @param key The property to be replaced.
+     * @param value The value to be associated with the property.
+     * @return The previous value associated with the property, or null if the property was not found.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object replace(String key, Object value) {
+        throw new UnsupportedOperationException("replace" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * The computed value associated with the property, or null if the property is not present.
+     *
+     * @param key The property whose value is to be computed if absent.
+     * @param mappingFunction The function to compute a value based on the property.
+     * @return The computed value associated with the property, or null if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object computeIfAbsent(String key, Function<? super String, ?> mappingFunction) {
+        throw new UnsupportedOperationException("computeIfAbsent" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * If the value for the specified property is present, attempts to compute a new mapping given the property and its current
+     * mapped value.
+     *
+     * @param key The property for which the mapping is to be computed.
+     * @param remappingFunction The function to compute a new mapping.
+     * @return The new value associated with the property, or null if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object computeIfPresent(String key, BiFunction<? super String, ? super Object, ?> remappingFunction) {
+        throw new UnsupportedOperationException("computeIfPresent" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * If the value for the specified property is present, attempts to compute a new mapping given the property and its current
+     * mapped value, or removes the property if the computed value is null.
+     *
+     * @param key The property for which the mapping is to be computed.
+     * @param remappingFunction The function to compute a new mapping.
+     * @return The new value associated with the property, or null if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object compute(String key, BiFunction<? super String, ? super Object, ?> remappingFunction) {
+        throw new UnsupportedOperationException("compute" + UNSUPPORTED_OP_ERR);
+    }
+
+    /**
+     * If the specified property is not already associated with a value or is associated with null, associates it with the
+     * given non-null value. Otherwise, replaces the associated value with the results of applying the given
+     * remapping function to the current and new values.
+     *
+     * @param key The property for which the mapping is to be merged.
+     * @param value The non-null value to be merged with the existing value.
+     * @param remappingFunction The function to merge the existing and new values.
+     * @return The new value associated with the property, or null if the property is not present.
+     * @throws UnsupportedOperationException always, as the method is not supported.
+     */
+    @Override
+    public Object merge(String key, Object value, BiFunction<? super Object, ? super Object, ?> remappingFunction) {
+        throw new UnsupportedOperationException("merge" + UNSUPPORTED_OP_ERR);
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapProcessingException.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapProcessingException.java
new file mode 100644
index 0000000000000..cb1e45a20b624
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapProcessingException.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common.helpers;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.OpenSearchWrapperException;
+
+/**
+ * An exception that indicates an error occurred while processing a {@link SearchRequestMap}.
+ */
+public class SearchRequestMapProcessingException extends OpenSearchException implements OpenSearchWrapperException {
+
+    /**
+     * Constructs a new SearchRequestMapProcessingException with the specified message.
+     *
+     * @param msg The error message.
+     * @param args Arguments to substitute in the error message.
+     */
+    public SearchRequestMapProcessingException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    /**
+     * Constructs a new SearchRequestMapProcessingException with the specified message and cause.
+     *
+     * @param msg The error message.
+     * @param cause The cause of the exception.
+     * @param args Arguments to substitute in the error message.
+     */
+    public SearchRequestMapProcessingException(String msg, Throwable cause, Object... args) {
+        super(msg, cause, args);
+    }
+}
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/package-info.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/package-info.java
new file mode 100644
index 0000000000000..b960ff72a9e2b
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/helpers/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Provides helper classes and utilities for working with search pipeline processors.
+ */
+package org.opensearch.search.pipeline.common.helpers;
diff --git a/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/package-info.java b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/package-info.java
new file mode 100644
index 0000000000000..9b065b4008021
--- /dev/null
+++ b/modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * A collection of commonly-useful request and response processors for use in search pipelines.
+ */
+package org.opensearch.search.pipeline.common;
diff --git a/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessorTests.java b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessorTests.java
new file mode 100644
index 0000000000000..576660d05b96d
--- /dev/null
+++ b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/FilterQueryRequestProcessorTests.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.index.query.BoolQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.test.AbstractBuilderTestCase;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+public class FilterQueryRequestProcessorTests extends AbstractBuilderTestCase {
+
+    public void testFilterQuery() throws Exception {
+        QueryBuilder filterQuery = new TermQueryBuilder("field", "value");
+        FilterQueryRequestProcessor filterQueryRequestProcessor = new FilterQueryRequestProcessor(null, null, false, filterQuery);
+        QueryBuilder incomingQuery = new TermQueryBuilder("text", "foo");
+        SearchSourceBuilder source = new SearchSourceBuilder().query(incomingQuery);
+        SearchRequest request = new SearchRequest().source(source);
+        SearchRequest transformedRequest = filterQueryRequestProcessor.processRequest(request);
+        assertEquals(new BoolQueryBuilder().must(incomingQuery).filter(filterQuery), transformedRequest.source().query());
+
+        // Test missing incoming query
+        request = new SearchRequest();
+        transformedRequest = filterQueryRequestProcessor.processRequest(request);
+        assertEquals(new BoolQueryBuilder().filter(filterQuery), transformedRequest.source().query());
+    }
+
+    public void testFactory() throws Exception {
+        FilterQueryRequestProcessor.Factory factory = new FilterQueryRequestProcessor.Factory(this.xContentRegistry());
+        Map<String, Object> configMap = new HashMap<>(Map.of("query", Map.of("term", Map.of("field", "value"))));
+        FilterQueryRequestProcessor processor = factory.create(Collections.emptyMap(), null, null, false, configMap, null);
+        assertEquals(new TermQueryBuilder("field", "value"), processor.filterQuery);
+
+        // Missing "query" parameter:
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> factory.create(Collections.emptyMap(), null, null, false, Collections.emptyMap(), null)
+        );
+    }
+}
diff --git a/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessorTests.java b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessorTests.java
new file mode 100644
index 0000000000000..b051a8123b354
--- /dev/null
+++ b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/RenameFieldResponseProcessorTests.java
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a.java
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.apache.lucene.search.TotalHits;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchResponseSections;
+import org.opensearch.common.document.DocumentField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.ingest.RandomDocumentPicks;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.SearchHits;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+public class RenameFieldResponseProcessorTests extends OpenSearchTestCase {
+
+    private SearchRequest createDummyRequest() {
+        QueryBuilder query = new TermQueryBuilder("field", "value");
+        SearchSourceBuilder source = new SearchSourceBuilder().query(query);
+        return new SearchRequest().source(source);
+    }
+
+    private SearchResponse createTestResponse(int size, boolean includeMapping) {
+        SearchHit[] hits = new SearchHit[size];
+        for (int i = 0; i < size; i++) {
+            Map<String, DocumentField> searchHitFields = new HashMap<>();
+            if (includeMapping) {
+                searchHitFields.put("field " + i, new DocumentField("value " + i, Collections.emptyList()));
+            }
+            searchHitFields.put("field " + i, new DocumentField("value " + i, Collections.emptyList()));
+            hits[i] = new SearchHit(i, "doc " + i, searchHitFields, Collections.emptyMap());
+            hits[i].sourceRef(new BytesArray("{ \"field " + i + "\" : \"value " + i + "\" }"));
+            hits[i].score(i);
+        }
+        SearchHits searchHits = new SearchHits(hits, new TotalHits(size * 2L, TotalHits.Relation.EQUAL_TO), size);
+        SearchResponseSections searchResponseSections = new SearchResponseSections(searchHits, null, null, false, false, null, 0);
+        return new SearchResponse(searchResponseSections, null, 1, 1, 0, 10, null, null);
+    }
+
+    public void testRenameResponse() throws Exception {
+        SearchRequest request = createDummyRequest();
+
+        RenameFieldResponseProcessor renameFieldResponseProcessor = new RenameFieldResponseProcessor(
+            null,
+            null,
+            false,
+            "field 0",
+            "new field",
+            false
+        );
+        SearchResponse response = createTestResponse(2, false);
+        SearchResponse renameResponse = renameFieldResponseProcessor.processResponse(request, createTestResponse(5, false));
+
+        assertNotEquals(response.getHits(), renameResponse.getHits());
+    }
+
+    public void testRenameResponseWithMapping() throws Exception {
+        SearchRequest request = createDummyRequest();
+
+        RenameFieldResponseProcessor renameFieldResponseProcessor = new RenameFieldResponseProcessor(
+            null,
+            null,
+            false,
+            "field 0",
+            "new field",
+            true
+        );
+        SearchResponse response = createTestResponse(5, true);
+        SearchResponse renameResponse = renameFieldResponseProcessor.processResponse(request, createTestResponse(5, true));
+
+        assertNotEquals(response.getHits(), renameResponse.getHits());
+
+        boolean foundField = false;
+        for (SearchHit hit : renameResponse.getHits().getHits()) {
+            if (hit.getFields().containsKey("new field")) {
+                foundField = true;
+            }
+        }
+        assertTrue(foundField);
+    }
+
+    public void testMissingField() throws Exception {
+        SearchRequest request = createDummyRequest();
+        RenameFieldResponseProcessor renameFieldResponseProcessor = new RenameFieldResponseProcessor(
+            null,
+            null,
+            false,
+            "field",
+            "new field",
+            false
+        );
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> renameFieldResponseProcessor.processResponse(request, createTestResponse(3, true))
+        );
+    }
+
+    public void testFactory() throws Exception {
+        String oldField = RandomDocumentPicks.randomFieldName(random());
+        String newField = RandomDocumentPicks.randomFieldName(random());
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", oldField);
+        config.put("target_field", newField);
+
+        RenameFieldResponseProcessor.Factory factory = new RenameFieldResponseProcessor.Factory();
+        RenameFieldResponseProcessor processor = factory.create(Collections.emptyMap(), null, null, false, config, null);
+        assertEquals(processor.getType(), "rename_field");
+        assertEquals(processor.getOldField(), oldField);
+        assertEquals(processor.getNewField(), newField);
+        assertFalse(processor.isIgnoreMissing());
+
+        expectThrows(
+            OpenSearchParseException.class,
+            () -> factory.create(Collections.emptyMap(), null, null, false, Collections.emptyMap(), null)
+        );
+    }
+}
diff --git a/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/ScriptRequestProcessorTests.java b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/ScriptRequestProcessorTests.java
new file mode 100644
index 0000000000000..fde9757312e30
--- /dev/null
+++ b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/ScriptRequestProcessorTests.java
@@ -0,0 +1,138 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.script.MockScriptEngine;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptModule;
+import org.opensearch.script.ScriptService;
+import org.opensearch.script.ScriptType;
+import org.opensearch.script.SearchScript;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.pipeline.common.helpers.SearchRequestMap;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.core.Is.is;
+
+public class ScriptRequestProcessorTests extends OpenSearchTestCase {
+
+    private ScriptService scriptService;
+    private Script script;
+    private SearchScript searchScript;
+
+    @Before
+    public void setupScripting() {
+        String scriptName = "search_script";
+        scriptService = new ScriptService(
+            Settings.builder().build(),
+            Map.of(Script.DEFAULT_SCRIPT_LANG, new MockScriptEngine(Script.DEFAULT_SCRIPT_LANG, Map.of(scriptName, ctx -> {
+                Object sourceObj = ctx.get("_source");
+                if (sourceObj instanceof Map) {
+                    Map<String, Object> source = (SearchRequestMap) sourceObj;
+
+                    // Update all modifiable source fields
+                    Integer from = (Integer) source.get("from");
+                    source.put("from", from + 10);
+
+                    Integer size = (Integer) source.get("size");
+                    source.put("size", size + 10);
+
+                    Boolean explain = (Boolean) source.get("explain");
+                    source.put("explain", !explain);
+
+                    Boolean version = (Boolean) source.get("version");
+                    source.put("version", !version);
+
+                    Boolean seqNoAndPrimaryTerm = (Boolean) source.get("seq_no_primary_term");
+                    source.put("seq_no_primary_term", !seqNoAndPrimaryTerm);
+
+                    Boolean trackScores = (Boolean) source.get("track_scores");
+                    source.put("track_scores", !trackScores);
+
+                    Integer trackTotalHitsUpTo = (Integer) source.get("track_total_hits");
+                    source.put("track_total_hits", trackTotalHitsUpTo + 1);
+
+                    Float minScore = (Float) source.get("min_score");
+                    source.put("min_score", minScore + 1.0f);
+
+                    Integer terminateAfter = (Integer) source.get("terminate_after");
+                    source.put("terminate_after", terminateAfter + 1);
+                }
+                return null;
+            }), Collections.emptyMap())),
+            new HashMap<>(ScriptModule.CORE_CONTEXTS)
+        );
+        script = new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap());
+        searchScript = scriptService.compile(script, SearchScript.CONTEXT).newInstance(script.getParams());
+    }
+
+    public void testScriptingWithoutPrecompiledScriptFactory() throws Exception {
+        ScriptRequestProcessor processor = new ScriptRequestProcessor(randomAlphaOfLength(10), null, false, script, null, scriptService);
+        SearchRequest searchRequest = new SearchRequest();
+        searchRequest.source(createSearchSourceBuilder());
+
+        assertNotNull(searchRequest);
+        processor.processRequest(searchRequest);
+        assertSearchRequest(searchRequest);
+    }
+
+    public void testScriptingWithPrecompiledIngestScript() throws Exception {
+        ScriptRequestProcessor processor = new ScriptRequestProcessor(
+            randomAlphaOfLength(10),
+            null,
+            false,
+            script,
+            searchScript,
+            scriptService
+        );
+        SearchRequest searchRequest = new SearchRequest();
+        searchRequest.source(createSearchSourceBuilder());
+
+        assertNotNull(searchRequest);
+        processor.processRequest(searchRequest);
+        assertSearchRequest(searchRequest);
+    }
+
+    private SearchSourceBuilder createSearchSourceBuilder() {
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        source.from(10);
+        source.size(20);
+        source.explain(true);
+        source.version(true);
+        source.seqNoAndPrimaryTerm(true);
+        source.trackScores(true);
+        source.trackTotalHitsUpTo(3);
+        source.minScore(1.0f);
+        source.timeout(new TimeValue(60, TimeUnit.SECONDS));
+        source.terminateAfter(5);
+        return source;
+    }
+
+    private void assertSearchRequest(SearchRequest searchRequest) {
+        assertThat(searchRequest.source().from(), is(20));
+        assertThat(searchRequest.source().size(), is(30));
+        assertThat(searchRequest.source().explain(), is(false));
+        assertThat(searchRequest.source().version(), is(false));
+        assertThat(searchRequest.source().seqNoAndPrimaryTerm(), is(false));
+        assertThat(searchRequest.source().trackScores(), is(false));
+        assertThat(searchRequest.source().trackTotalHitsUpTo(), is(4));
+        assertThat(searchRequest.source().minScore(), is(2.0f));
+        assertThat(searchRequest.source().timeout(), is(new TimeValue(60, TimeUnit.SECONDS)));
+        assertThat(searchRequest.source().terminateAfter(), is(6));
+    }
+}
diff --git a/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapTests.java b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapTests.java
new file mode 100644
index 0000000000000..5572f28335e1c
--- /dev/null
+++ b/modules/search-pipeline-common/src/test/java/org/opensearch/search/pipeline/common/helpers/SearchRequestMapTests.java
@@ -0,0 +1,149 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.search.pipeline.common.helpers;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.test.AbstractBuilderTestCase;
+
+public class SearchRequestMapTests extends AbstractBuilderTestCase {
+
+    public void testEmptyMap() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        assertTrue(map.isEmpty());
+    }
+
+    public void testGet() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        source.from(10);
+        source.size(20);
+        source.explain(true);
+        source.version(true);
+        source.seqNoAndPrimaryTerm(true);
+        source.trackScores(true);
+        source.trackTotalHitsUpTo(3);
+        source.minScore(1.0f);
+        source.terminateAfter(5);
+        searchRequest.source(source);
+
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        assertEquals(10, map.get("from"));
+        assertEquals(20, map.get("size"));
+        assertEquals(true, map.get("explain"));
+        assertEquals(true, map.get("version"));
+        assertEquals(true, map.get("seq_no_primary_term"));
+        assertEquals(true, map.get("track_scores"));
+        assertEquals(3, map.get("track_total_hits"));
+        assertEquals(1.0f, map.get("min_score"));
+        assertEquals(5, map.get("terminate_after"));
+    }
+
+    public void testPut() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        searchRequest.source(source);
+
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        assertEquals(-1, map.put("from", 10));
+        assertEquals(10, map.get("from"));
+
+        assertEquals(-1, map.put("size", 20));
+        assertEquals(20, map.get("size"));
+
+        assertNull(map.put("explain", true));
+        assertEquals(true, map.get("explain"));
+
+        assertNull(map.put("version", true));
+        assertEquals(true, map.get("version"));
+
+        assertNull(map.put("seq_no_primary_term", true));
+        assertEquals(true, map.get("seq_no_primary_term"));
+
+        assertEquals(false, map.put("track_scores", true));
+        assertEquals(true, map.get("track_scores"));
+
+        assertNull(map.put("track_total_hits", 3));
+        assertEquals(3, map.get("track_total_hits"));
+
+        assertNull(map.put("min_score", 1.0f));
+        assertEquals(1.0f, map.get("min_score"));
+
+        assertEquals(0, map.put("terminate_after", 5));
+        assertEquals(5, map.get("terminate_after"));
+    }
+
+    public void testUnsupportedOperationException() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        searchRequest.source(source);
+
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        assertThrows(UnsupportedOperationException.class, () -> map.size());
+        assertThrows(UnsupportedOperationException.class, () -> map.containsValue(null));
+        assertThrows(UnsupportedOperationException.class, () -> map.remove(null));
+        assertThrows(UnsupportedOperationException.class, () -> map.putAll(null));
+        assertThrows(UnsupportedOperationException.class, map::clear);
+        assertThrows(UnsupportedOperationException.class, map::keySet);
+        assertThrows(UnsupportedOperationException.class, map::values);
+        assertThrows(UnsupportedOperationException.class, map::entrySet);
+        assertThrows(UnsupportedOperationException.class, () -> map.getOrDefault(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.forEach(null));
+        assertThrows(UnsupportedOperationException.class, () -> map.replaceAll(null));
+        assertThrows(UnsupportedOperationException.class, () -> map.putIfAbsent(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.remove(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.replace(null, null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.replace(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.computeIfAbsent(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.computeIfPresent(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.compute(null, null));
+        assertThrows(UnsupportedOperationException.class, () -> map.merge(null, null, null));
+    }
+
+    public void testIllegalArgumentException() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        searchRequest.source(source);
+
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        try {
+            map.get(1);
+            fail("Expected IllegalArgumentException");
+        } catch (IllegalArgumentException e) {
+            // expected
+        }
+    }
+
+    public void testSearchRequestMapProcessingException() {
+        SearchRequest searchRequest = new SearchRequest();
+        SearchSourceBuilder source = new SearchSourceBuilder();
+        searchRequest.source(source);
+
+        SearchRequestMap map = new SearchRequestMap(searchRequest);
+
+        try {
+            map.get("unsupported_key");
+            fail("Expected SearchRequestMapProcessingException");
+        } catch (SearchRequestMapProcessingException e) {
+            // expected
+        }
+
+        try {
+            map.put("unsupported_key", 10);
+            fail("Expected SearchRequestMapProcessingException");
+        } catch (SearchRequestMapProcessingException e) {
+            // expected
+        }
+    }
+}
diff --git a/modules/search-pipeline-common/src/yamlRestTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonYamlTestSuiteIT.java b/modules/search-pipeline-common/src/yamlRestTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonYamlTestSuiteIT.java
new file mode 100644
index 0000000000000..d4d53b158420a
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/java/org/opensearch/search/pipeline/common/SearchPipelineCommonYamlTestSuiteIT.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline.common;
+
+import com.carrotsearch.randomizedtesting.annotations.Name;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
+import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
+
+public class SearchPipelineCommonYamlTestSuiteIT extends OpenSearchClientYamlSuiteTestCase {
+    public SearchPipelineCommonYamlTestSuiteIT(@Name("yaml") ClientYamlTestCandidate testCandidate) {
+        super(testCandidate);
+    }
+
+    @ParametersFactory
+    public static Iterable<Object[]> parameters() throws Exception {
+        return OpenSearchClientYamlSuiteTestCase.createParameters();
+    }
+}
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/10_basic.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/10_basic.yml
new file mode 100644
index 0000000000000..ca53f6cd6a7e8
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/10_basic.yml
@@ -0,0 +1,17 @@
+"Search pipeline common installed":
+  - skip:
+      reason: "contains is a newly added assertion"
+      features: contains
+  - do:
+      cluster.state: {}
+
+  # Get cluster-manager node id
+  - set: { cluster_manager_node: cluster_manager }
+
+  - do:
+      nodes.info: {}
+
+  - contains:  { nodes.$cluster_manager.modules: { name: search-pipeline-common } }
+  - contains:  { nodes.$cluster_manager.search_pipelines.request_processors: { type: filter_query } }
+  - contains:  { nodes.$cluster_manager.search_pipelines.request_processors: { type: script } }
+  - contains:  { nodes.$cluster_manager.search_pipelines.response_processors: { type: rename_field } }
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/20_crud.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/20_crud.yml
new file mode 100644
index 0000000000000..9b86f6dcc06c2
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/20_crud.yml
@@ -0,0 +1,47 @@
+---
+teardown:
+ - do:
+     search_pipeline.delete:
+       id: "my_pipeline"
+       ignore: 404
+
+---
+"Test basic pipeline crud":
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "request_processors": [
+              {
+                "filter_query" : {
+                  "query" : {
+                    "term" : {
+                      "field" : "value"
+                    }
+                  }
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.description: "_description" }
+
+  - do:
+      search_pipeline.get: {}
+  - match: { my_pipeline.description: "_description" }
+
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+  - match: { acknowledged: true }
+
+  - do:
+      catch: missing
+      search_pipeline.get:
+        id: "my_pipeline"
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/25_empty_pipeline.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/25_empty_pipeline.yml
new file mode 100644
index 0000000000000..0481d27bb3f4b
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/25_empty_pipeline.yml
@@ -0,0 +1,47 @@
+---
+teardown:
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test explicitly empty pipeline is no-op":
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "description": "_description"
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: {
+          "field" : "foo"
+        }
+  - do:
+      index:
+        index: test
+        id: 2
+        body: {
+          "field": "value"
+        }
+
+  - do:
+      indices.refresh:
+        index: test
+
+  - do:
+      search:
+        index: test
+  - match: { hits.total.value: 2 }
+
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+  - match: { hits.total.value: 2 }
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/30_filter_query.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/30_filter_query.yml
new file mode 100644
index 0000000000000..d5fe91aab5378
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/30_filter_query.yml
@@ -0,0 +1,148 @@
+---
+teardown:
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test filter_query processor":
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "description": "_description",
+            "request_processors": [
+              {
+                "filter_query" : {
+                  "query" : {
+                    "term" : {
+                      "field" : "value"
+                    }
+                  }
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: {
+          "field": "foo"
+        }
+  - do:
+      index:
+        index: test
+        id: 2
+        body: {
+          "field": "value"
+        }
+
+  - do:
+      indices.refresh:
+        index: test
+
+  - do:
+      search:
+        body: { }
+  - match: { hits.total.value: 2 }
+
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: { }
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._id: "2" }
+
+  # Should also work with no search body specified
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._id: "2" }
+
+  # Should also work with existing query
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: {
+          "query": {
+            "term": {
+              "field": "value"
+            }
+          }
+        }
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._id: "2" }
+
+  # Should work with inline query
+  - do:
+      search:
+        index: test
+        body: {
+          "search_pipeline" : {
+            "request_processors" : [
+              "filter_query": {
+                "query": {
+                  "term": {
+                    "field": "foo"
+                  }
+                }
+              }
+            ]
+          }
+        }
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._id: "1" }
+
+  # Make it the default for the index
+  - do:
+      indices.put_settings:
+        index: test
+        body:
+          index.search.default_pipeline: my_pipeline
+
+  - do:
+      search:
+        index: test
+        body: { }
+  - match: { hits.total.value: 1 }
+
+  # Explicitly bypass the pipeline to match both docs
+  - do:
+      search:
+        search_pipeline: _none
+        index: test
+        body: { }
+  - match: { hits.total.value: 2 }
+---
+"Test invalid inline query":
+  - do:
+      catch: bad_request
+      search:
+        index: test
+        body: {
+          search_pipeline: {
+            "request_processors": [
+              {
+                "filter_query": {
+                  "query": {
+                    "woozlewuzzle": {
+                      "field": "foo"
+                    }
+                  }
+                }
+              }
+            ]
+          }
+        }
+  - match: { status: 400 }
+  - match: { error.type: "parsing_exception"}
+  - match: { error.reason: "unknown query [woozlewuzzle]"}
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/40_rename_response.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/40_rename_response.yml
new file mode 100644
index 0000000000000..0528440f7584d
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/40_rename_response.yml
@@ -0,0 +1,180 @@
+---
+teardown:
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test filter_query processor":
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "description": "test pipeline",
+            "response_processors": [
+              {
+                "rename_field":
+                  {
+                    "field": "a",
+                    "target_field": "b"
+                  }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline_2"
+        body: >
+          {
+            "description": "test pipeline with ignore missing true",
+            "response_processors": [
+              {
+                "rename_field":
+                  {
+                    "field": "aa",
+                    "target_field": "b",
+                    "ignore_missing": true
+                  }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline_3"
+        body: >
+          {
+            "description": "test pipeline with ignore missing false",
+            "response_processors": [
+              {
+                "rename_field":
+                  {
+                    "field": "aa",
+                    "target_field": "b",
+                    "ignore_missing": false
+                  }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline_4"
+        body: >
+          {
+            "description": "test pipeline with ignore missing false and ignore failure true",
+            "response_processors": [
+              {
+                "rename_field":
+                  {
+                    "field": "aa",
+                    "target_field": "b",
+                    "ignore_missing": false,
+                    "ignore_failure": true
+                  }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      indices.create:
+        index: test
+
+  - do:
+      indices.put_mapping:
+        index: test
+        body:
+          properties:
+            a:
+              type: keyword
+              store: true
+              doc_values: true
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: {
+          "a": "foo"
+        }
+
+  - do:
+      indices.refresh:
+        index: test
+
+  - do:
+      search:
+        body: { }
+  - match: { hits.total.value: 1 }
+
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: { }
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._source: { "b": "foo" } }
+
+  # Should also work with no search body specified
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._source: { "b": "foo" } }
+
+  # Pipeline with ignore_missing set to true
+  # Should still pass even though index does not contain field
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline_2"
+  - match: { hits.total.value: 1 }
+  - match: {hits.hits.0._source: { "a": "foo" } }
+
+  # Pipeline with ignore_missing set to false
+  # Should throw illegal_argument_exception
+  - do:
+      catch: bad_request
+      search:
+        index: test
+        search_pipeline: "my_pipeline_3"
+  - match: { error.type: "illegal_argument_exception" }
+
+  # Pipeline with ignore_missing set to false and ignore_failure set to true
+  # Should return while catching error
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline_4"
+  - match: { hits.total.value: 1 }
+  - match: {hits.hits.0._source: { "a": "foo" } }
+
+  # No source, using stored_fields
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: {
+          "_source": false,
+          "stored_fields": [ "a" ]
+        }
+  - match: { hits.hits.0.fields: { "b": ["foo"] } }
+
+  # No source, using docvalue_fields
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: {
+          "_source": false,
+          "docvalue_fields": [ "a" ]
+        }
+  - match: { hits.hits.0.fields: { "b": [ "foo" ] } }
diff --git a/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/50_script_processor.yml b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/50_script_processor.yml
new file mode 100644
index 0000000000000..7a01e68acf75c
--- /dev/null
+++ b/modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/50_script_processor.yml
@@ -0,0 +1,94 @@
+---
+teardown:
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+        ignore: 404
+
+---
+"Test empty script in script processor":
+  - do:
+      catch: bad_request
+      search_pipeline.put:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "request_processors": [
+              {
+                "script" : {
+                  "tag": "empty_script",
+                  "lang": "painless",
+                  "source" : ""
+                }
+              }
+            ]
+          }
+
+  - match: { status: 400 }
+  - match: { error.root_cause.0.type: "script_exception" }
+
+---
+"Test supported search source builder fields":
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "description": "_description",
+            "request_processors": [
+              {
+                "script" : {
+                  "tag": "working",
+                  "lang" : "painless",
+                  "source" : "ctx._source['size'] += 10; ctx._source['from'] = ctx._source['from'] <= 0 ? ctx._source['from'] : ctx._source['from'] - 1 ; ctx._source['explain'] = !ctx._source['explain']; ctx._source['version'] = !ctx._source['version']; ctx._source['seq_no_primary_term'] = !ctx._source['seq_no_primary_term']; ctx._source['track_scores'] = !ctx._source['track_scores']; ctx._source['track_total_hits'] = 1; ctx._source['min_score'] -= 0.9; ctx._source['terminate_after'] += 2; ctx._source['profile'] = !ctx._source['profile'];"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: {
+          "field": 2
+        }
+  - do:
+      index:
+        index: test
+        id: 2
+        body: {
+          "field": 3
+        }
+
+  - do:
+      indices.refresh:
+        index: test
+
+  - do:
+      search:
+        index: test
+        search_pipeline: "my_pipeline"
+        body: {
+          "from": 1,
+          "size": 1,
+          "explain": true,
+          "version": true,
+          "seq_no_primary_term": true,
+          "track_scores": true,
+          "track_total_hits": true,
+          "min_score": 1.0,
+          "timeout": "60s",
+          "terminate_after": 2,
+          "profile": true
+        }
+  - length: { hits.hits: 2 }
+  - is_false: hits.hits.0._explanation
+  - is_false: hits.hits.1._explanation
+  - is_false: hits.hits.0._seq_no
+  - is_false: hits.hits.1._seq_no
+  - is_false: hits.hits.0._primary_term
+  - is_false: hits.hits.1._primary_term
+  - is_false: profile
diff --git a/modules/systemd/build.gradle b/modules/systemd/build.gradle
index b157fd9321fc9..26e094a9eeae1 100644
--- a/modules/systemd/build.gradle
+++ b/modules/systemd/build.gradle
@@ -32,4 +32,3 @@ opensearchplugin {
   description 'Integrates OpenSearch with systemd'
   classname 'org.opensearch.systemd.SystemdPlugin'
 }
-
diff --git a/modules/systemd/src/main/java/org/opensearch/systemd/SystemdPlugin.java b/modules/systemd/src/main/java/org/opensearch/systemd/SystemdPlugin.java
index 3a2d51950f0be..35aae06fe9deb 100644
--- a/modules/systemd/src/main/java/org/opensearch/systemd/SystemdPlugin.java
+++ b/modules/systemd/src/main/java/org/opensearch/systemd/SystemdPlugin.java
@@ -34,14 +34,13 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.Build;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.plugins.ClusterPlugin;
@@ -68,20 +67,10 @@ final boolean isEnabled() {
 
     @SuppressWarnings("unused")
     public SystemdPlugin() {
-        this(true, Build.CURRENT.type(), System.getenv("OPENSEARCH_SD_NOTIFY"));
+        this(System.getenv("OPENSEARCH_SD_NOTIFY"));
     }
 
-    SystemdPlugin(final boolean assertIsPackageDistribution, final Build.Type buildType, final String esSDNotify) {
-        final boolean isPackageDistribution = buildType == Build.Type.DEB || buildType == Build.Type.RPM;
-        if (assertIsPackageDistribution) {
-            // our build is configured to only include this module in the package distributions
-            assert isPackageDistribution : buildType;
-        }
-        if (isPackageDistribution == false) {
-            logger.debug("disabling sd_notify as the build type [{}] is not a package distribution", buildType);
-            enabled = false;
-            return;
-        }
+    SystemdPlugin(final String esSDNotify) {
         logger.trace("OPENSEARCH_SD_NOTIFY is set to [{}]", esSDNotify);
         if (esSDNotify == null) {
             enabled = false;
diff --git a/modules/systemd/src/test/java/org/opensearch/systemd/SystemdPluginTests.java b/modules/systemd/src/test/java/org/opensearch/systemd/SystemdPluginTests.java
index cc8ee649ab782..63d97a7486f58 100644
--- a/modules/systemd/src/test/java/org/opensearch/systemd/SystemdPluginTests.java
+++ b/modules/systemd/src/test/java/org/opensearch/systemd/SystemdPluginTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.systemd;
 
-import org.opensearch.Build;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.test.OpenSearchTestCase;
@@ -58,13 +57,6 @@
 import static org.mockito.Mockito.when;
 
 public class SystemdPluginTests extends OpenSearchTestCase {
-
-    private final Build.Type randomPackageBuildType = randomFrom(Build.Type.DEB, Build.Type.RPM);
-    private final Build.Type randomNonPackageBuildType = randomValueOtherThanMany(
-        t -> t == Build.Type.DEB || t == Build.Type.RPM,
-        () -> randomFrom(Build.Type.values())
-    );
-
     final Scheduler.Cancellable extender = mock(Scheduler.Cancellable.class);
     final ThreadPool threadPool = mock(ThreadPool.class);
 
@@ -74,29 +66,15 @@ public class SystemdPluginTests extends OpenSearchTestCase {
             .thenReturn(extender);
     }
 
-    public void testIsEnabled() {
-        final SystemdPlugin plugin = new SystemdPlugin(false, randomPackageBuildType, Boolean.TRUE.toString());
-        plugin.createComponents(null, null, threadPool, null, null, null, null, null, null, null, null);
-        assertTrue(plugin.isEnabled());
-        assertNotNull(plugin.extender());
-    }
-
-    public void testIsNotPackageDistribution() {
-        final SystemdPlugin plugin = new SystemdPlugin(false, randomNonPackageBuildType, Boolean.TRUE.toString());
-        plugin.createComponents(null, null, threadPool, null, null, null, null, null, null, null, null);
-        assertFalse(plugin.isEnabled());
-        assertNull(plugin.extender());
-    }
-
     public void testIsImplicitlyNotEnabled() {
-        final SystemdPlugin plugin = new SystemdPlugin(false, randomPackageBuildType, null);
+        final SystemdPlugin plugin = new SystemdPlugin(null);
         plugin.createComponents(null, null, threadPool, null, null, null, null, null, null, null, null);
         assertFalse(plugin.isEnabled());
         assertNull(plugin.extender());
     }
 
     public void testIsExplicitlyNotEnabled() {
-        final SystemdPlugin plugin = new SystemdPlugin(false, randomPackageBuildType, Boolean.FALSE.toString());
+        final SystemdPlugin plugin = new SystemdPlugin(Boolean.FALSE.toString());
         plugin.createComponents(null, null, threadPool, null, null, null, null, null, null, null, null);
         assertFalse(plugin.isEnabled());
         assertNull(plugin.extender());
@@ -107,7 +85,7 @@ public void testInvalid() {
             s -> Boolean.TRUE.toString().equals(s) || Boolean.FALSE.toString().equals(s),
             () -> randomAlphaOfLength(4)
         );
-        final RuntimeException e = expectThrows(RuntimeException.class, () -> new SystemdPlugin(false, randomPackageBuildType, esSDNotify));
+        final RuntimeException e = expectThrows(RuntimeException.class, () -> new SystemdPlugin(esSDNotify));
         assertThat(e, hasToString(containsString("OPENSEARCH_SD_NOTIFY set to unexpected value [" + esSDNotify + "]")));
     }
 
@@ -174,7 +152,7 @@ private void runTest(
         final AtomicBoolean invoked = new AtomicBoolean();
         final AtomicInteger invokedUnsetEnvironment = new AtomicInteger();
         final AtomicReference<String> invokedState = new AtomicReference<>();
-        final SystemdPlugin plugin = new SystemdPlugin(false, randomPackageBuildType, esSDNotify) {
+        final SystemdPlugin plugin = new SystemdPlugin(esSDNotify) {
 
             @Override
             int sd_notify(final int unset_environment, final String state) {
diff --git a/modules/transport-netty4/build.gradle b/modules/transport-netty4/build.gradle
index f0029837c7d03..a0ae6619199d2 100644
--- a/modules/transport-netty4/build.gradle
+++ b/modules/transport-netty4/build.gradle
@@ -31,6 +31,7 @@
 
 import org.opensearch.gradle.info.BuildParams
 import org.opensearch.gradle.test.RestIntegTestTask
+import org.opensearch.gradle.test.TestTask
 import org.opensearch.gradle.test.rest.JavaRestTestPlugin
 import org.opensearch.gradle.test.InternalClusterTestPlugin
 
@@ -38,6 +39,9 @@ apply plugin: 'opensearch.yaml-rest-test'
 apply plugin: 'opensearch.java-rest-test'
 apply plugin: 'opensearch.internal-cluster-test'
 
+// The transport-netty4 plugin is published to maven
+apply plugin: 'opensearch.publish'
+
 /*
  TODOs:
    * fix permissions such that only netty4 can open sockets etc?
@@ -59,6 +63,7 @@ dependencies {
   api "io.netty:netty-handler:${versions.netty}"
   api "io.netty:netty-resolver:${versions.netty}"
   api "io.netty:netty-transport:${versions.netty}"
+  api "io.netty:netty-transport-native-unix-common:${versions.netty}"
 }
 
 restResources {
@@ -87,13 +92,13 @@ javaRestTest {
   systemProperty 'opensearch.set.netty.runtime.available.processors', 'false'
 }
 
-TaskProvider<Test> pooledTest = tasks.register("pooledTest", Test) {
+TaskProvider<Test> pooledTest = tasks.register("pooledTest", TestTask) {
   include '**/*Tests.class'
   systemProperty 'opensearch.set.netty.runtime.available.processors', 'false'
   systemProperty 'opensearch.use_unpooled_allocator', 'false'
 }
 
-TaskProvider<Test> pooledInternalClusterTest = tasks.register("pooledInternalClusterTest", Test) {
+TaskProvider<Test> pooledInternalClusterTest = tasks.register("pooledInternalClusterTest", TestTask) {
   include '**/*IT.class'
   systemProperty 'opensearch.set.netty.runtime.available.processors', 'false'
   systemProperty 'opensearch.use_unpooled_allocator', 'false'
@@ -120,17 +125,11 @@ thirdPartyAudit {
     'com.aayushatharva.brotli4j.Brotli4jLoader',
     'com.aayushatharva.brotli4j.decoder.DecoderJNI$Status',
     'com.aayushatharva.brotli4j.decoder.DecoderJNI$Wrapper',
-    'com.aayushatharva.brotli4j.encoder.Encoder',
+    'com.aayushatharva.brotli4j.encoder.BrotliEncoderChannel',
     'com.aayushatharva.brotli4j.encoder.Encoder$Mode',
     'com.aayushatharva.brotli4j.encoder.Encoder$Parameters',
     // classes are missing
 
-    // from io.netty.handler.codec.protobuf.ProtobufDecoder (netty)
-    'com.google.protobuf.ExtensionRegistry',
-    'com.google.protobuf.MessageLite$Builder',
-    'com.google.protobuf.MessageLite',
-    'com.google.protobuf.Parser',
-
     // from io.netty.logging.CommonsLoggerFactory (netty)
     'org.apache.commons.logging.Log',
     'org.apache.commons.logging.LogFactory',
@@ -141,6 +140,7 @@ thirdPartyAudit {
 
     // from io.netty.handler.ssl.OpenSslEngine (netty)
     'io.netty.internal.tcnative.Buffer',
+    'io.netty.internal.tcnative.CertificateCompressionAlgo',
     'io.netty.internal.tcnative.Library',
     'io.netty.internal.tcnative.SSL',
     'io.netty.internal.tcnative.SSLContext',
@@ -150,6 +150,12 @@ thirdPartyAudit {
     'org.bouncycastle.cert.X509v3CertificateBuilder',
     'org.bouncycastle.cert.jcajce.JcaX509CertificateConverter',
     'org.bouncycastle.operator.jcajce.JcaContentSignerBuilder',
+    'org.bouncycastle.openssl.PEMEncryptedKeyPair',
+    'org.bouncycastle.openssl.PEMParser',
+    'org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter',
+    'org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8DecryptorProviderBuilder',
+    'org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder',
+    'org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo',
 
     // from io.netty.handler.ssl.JettyNpnSslEngine (netty)
     'org.eclipse.jetty.npn.NextProtoNego$ClientProvider',
@@ -177,15 +183,8 @@ thirdPartyAudit {
     'org.slf4j.LoggerFactory',
     'org.slf4j.spi.LocationAwareLogger',
 
-    'com.github.luben.zstd.Zstd',
-    'com.google.protobuf.ExtensionRegistryLite',
-    'com.google.protobuf.MessageLiteOrBuilder',
     'com.google.protobuf.nano.CodedOutputByteBufferNano',
     'com.google.protobuf.nano.MessageNano',
-    'com.jcraft.jzlib.Deflater',
-    'com.jcraft.jzlib.Inflater',
-    'com.jcraft.jzlib.JZlib$WrapperType',
-    'com.jcraft.jzlib.JZlib',
     'com.ning.compress.BufferRecycler',
     'com.ning.compress.lzf.ChunkDecoder',
     'com.ning.compress.lzf.ChunkEncoder',
@@ -227,7 +226,8 @@ thirdPartyAudit {
     'io.netty.util.internal.PlatformDependent0$1',
     'io.netty.util.internal.PlatformDependent0$2',
     'io.netty.util.internal.PlatformDependent0$3',
-    'io.netty.util.internal.PlatformDependent0$5',
+    'io.netty.util.internal.PlatformDependent0$4',
+    'io.netty.util.internal.PlatformDependent0$6',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueConsumerNodeRef',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueProducerNodeRef',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseMpscLinkedArrayQueueColdProducerFields',
@@ -239,6 +239,11 @@ thirdPartyAudit {
     'io.netty.util.internal.shaded.org.jctools.queues.MpscArrayQueueProducerLimitField',
     'io.netty.util.internal.shaded.org.jctools.util.UnsafeAccess',
     'io.netty.util.internal.shaded.org.jctools.util.UnsafeRefArrayAccess',
-    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator'
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$1',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$2',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$3',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$4',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$5'
   )
 }
diff --git a/modules/transport-netty4/licenses/netty-buffer-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-buffer-4.1.73.Final.jar.sha1
deleted file mode 100644
index e5833785ebb7e..0000000000000
--- a/modules/transport-netty4/licenses/netty-buffer-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-244a569c9aae973f6f485ac9801d79c1eca36daa
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-buffer-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-buffer-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..5b393be40e945
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-buffer-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9f02dcb9b15a647a56af210dffdc294a57922fb0
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-codec-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-codec-4.1.73.Final.jar.sha1
deleted file mode 100644
index dcdc1e4e58afe..0000000000000
--- a/modules/transport-netty4/licenses/netty-codec-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-9496a30a349863a4c6fa10d5c36b4f3b495d3a31
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-codec-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-codec-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..45ea27d29a183
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-codec-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9984cbd6e5d55c768f198e975d8aaf7fd42a4602
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-codec-http-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-codec-http-4.1.73.Final.jar.sha1
deleted file mode 100644
index 374cfb98614d5..0000000000000
--- a/modules/transport-netty4/licenses/netty-codec-http-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1ceeac4429b9bd517dc05e376a144bbe6b6bd038
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-codec-http-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-codec-http-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6bb7fcd68b272
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-codec-http-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+7142095066eaebd5f29b88c41af7b383b6a953f6
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-common-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-common-4.1.73.Final.jar.sha1
deleted file mode 100644
index e80a6e2569d81..0000000000000
--- a/modules/transport-netty4/licenses/netty-common-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-27731b58d741b6faa6a00fa3285e7a55cc47be01
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-common-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..d53adfa649f5f
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+278f6dfa49d6bd75c40ae1470eb165716f87dce0
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-handler-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-handler-4.1.73.Final.jar.sha1
deleted file mode 100644
index 0e227997874bf..0000000000000
--- a/modules/transport-netty4/licenses/netty-handler-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1a2231c0074f88254865c3769a4b5842939ea04d
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-handler-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-handler-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..258f7c957dda0
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-handler-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+742693761d7ea4c038bccfda96bb38194720b80d
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-resolver-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-resolver-4.1.73.Final.jar.sha1
deleted file mode 100644
index ba24531724fb5..0000000000000
--- a/modules/transport-netty4/licenses/netty-resolver-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-bfe83710f0c1739019613e81a06101020ca65def
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-resolver-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-resolver-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..b8bc0a4370f58
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-resolver-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+080e45397d9d5b134477de3ffd0f94283b908621
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-transport-4.1.73.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-transport-4.1.73.Final.jar.sha1
deleted file mode 100644
index 6a8647497f210..0000000000000
--- a/modules/transport-netty4/licenses/netty-transport-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-abb155ddff196ccedfe85b810d4b9375ef85fcfa
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-transport-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-transport-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..247975e0a64c7
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-transport-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9ca2e3ae19a6713b749df154622115f480b6716c
\ No newline at end of file
diff --git a/modules/transport-netty4/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1 b/modules/transport-netty4/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6b7b66ea768e3
--- /dev/null
+++ b/modules/transport-netty4/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+cb0fc6c31c387404212949c57950b5d72ce908b9
\ No newline at end of file
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4HttpRequestSizeLimitIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4HttpRequestSizeLimitIT.java
index 08df9259d475f..dcaa9553f5b1f 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4HttpRequestSizeLimitIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4HttpRequestSizeLimitIT.java
@@ -32,15 +32,12 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.util.ReferenceCounted;
 import org.opensearch.OpenSearchNetty4IntegTestCase;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
@@ -50,6 +47,10 @@
 import java.util.Collection;
 import java.util.List;
 
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.util.ReferenceCounted;
+
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.hasSize;
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4PipeliningIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4PipeliningIT.java
index 2bd1fa07f8afc..c0e1f817c3c50 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4PipeliningIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4PipeliningIT.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.util.ReferenceCounted;
 import org.opensearch.OpenSearchNetty4IntegTestCase;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
@@ -43,6 +41,9 @@
 import java.util.Collection;
 import java.util.Locale;
 
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.util.ReferenceCounted;
+
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/rest/discovery/Zen2RestApiIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/rest/discovery/Zen2RestApiIT.java
index 198cc11d824e7..2c75123c5d825 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/rest/discovery/Zen2RestApiIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/rest/discovery/Zen2RestApiIT.java
@@ -47,8 +47,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.http.HttpServerTransport;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -69,7 +69,7 @@ protected boolean addMockHttpTransport() {
     }
 
     public void testRollingRestartOfTwoNodeCluster() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(1);
+        internalCluster().setBootstrapClusterManagerNodeIndex(1);
         final List<String> nodes = internalCluster().startNodes(2);
         createIndex(
             "test",
@@ -135,7 +135,7 @@ public Settings onNodeStopped(String nodeName) throws IOException {
     }
 
     public void testClearVotingTombstonesNotWaitingForRemoval() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
         List<String> nodes = internalCluster().startNodes(3);
         ensureStableCluster(3);
         RestClient restClient = getRestClient();
@@ -150,7 +150,7 @@ public void testClearVotingTombstonesNotWaitingForRemoval() throws Exception {
     }
 
     public void testClearVotingTombstonesWaitingForRemoval() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
         List<String> nodes = internalCluster().startNodes(3);
         ensureStableCluster(3);
         RestClient restClient = getRestClient();
@@ -165,7 +165,7 @@ public void testClearVotingTombstonesWaitingForRemoval() throws Exception {
     }
 
     public void testFailsOnUnknownNode() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
         internalCluster().startNodes(3);
         ensureStableCluster(3);
         RestClient restClient = getRestClient();
@@ -176,13 +176,13 @@ public void testFailsOnUnknownNode() throws Exception {
             assertThat(e.getResponse().getStatusLine().getStatusCode(), is(400));
             assertThat(
                 e.getMessage(),
-                Matchers.containsString("add voting config exclusions request for [invalid] matched no master-eligible nodes")
+                Matchers.containsString("add voting config exclusions request for [invalid] matched no cluster-manager-eligible nodes")
             );
         }
     }
 
     public void testRemoveTwoNodesAtOnce() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
         List<String> nodes = internalCluster().startNodes(3);
         ensureStableCluster(3);
         RestClient restClient = getRestClient();
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportMultiPortIntegrationIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportMultiPortIntegrationIT.java
index 3ff3938d23f65..4004d3d1a029d 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportMultiPortIntegrationIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportMultiPortIntegrationIT.java
@@ -36,8 +36,8 @@
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
 import org.opensearch.test.junit.annotations.Network;
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportPublishAddressIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportPublishAddressIT.java
index a572a181a46fd..f23df4b48a854 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportPublishAddressIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/Netty4TransportPublishAddressIT.java
@@ -38,8 +38,8 @@
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.transport.Netty4Plugin;
 import org.opensearch.transport.TransportInfo;
diff --git a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/OpenSearchLoggingHandlerIT.java b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/OpenSearchLoggingHandlerIT.java
index ea3f21dd0ed3b..b8369acdf9dc6 100644
--- a/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/OpenSearchLoggingHandlerIT.java
+++ b/modules/transport-netty4/src/internalClusterTest/java/org/opensearch/transport/netty4/OpenSearchLoggingHandlerIT.java
@@ -36,9 +36,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.OpenSearchNetty4IntegTestCase;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsRequest;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.transport.TcpTransport;
 import org.opensearch.transport.TransportLogger;
diff --git a/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4BadRequestIT.java b/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4BadRequestIT.java
index e9de417f1efe6..f7e1c6106cf5a 100644
--- a/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4BadRequestIT.java
+++ b/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4BadRequestIT.java
@@ -38,7 +38,7 @@
 import org.opensearch.client.ResponseException;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.http.HttpTransportSettings;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.opensearch.test.rest.yaml.ObjectPath;
@@ -47,7 +47,7 @@
 import java.nio.charset.Charset;
 import java.util.Map;
 
-import static org.opensearch.rest.RestStatus.BAD_REQUEST;
+import static org.opensearch.core.rest.RestStatus.BAD_REQUEST;
 import static org.opensearch.test.hamcrest.RegexMatcher.matches;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -86,7 +86,7 @@ public void testBadRequest() throws IOException {
             () -> client().performRequest(new Request(randomFrom("GET", "POST", "PUT"), path))
         );
         assertThat(e.getResponse().getStatusLine().getStatusCode(), equalTo(BAD_REQUEST.getStatus()));
-        assertThat(e, hasToString(containsString("too_long_frame_exception")));
+        assertThat(e, hasToString(containsString("too_long_http_line_exception")));
         assertThat(e, hasToString(matches("An HTTP line is larger than \\d+ bytes")));
     }
 
diff --git a/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4HeadBodyIsEmptyIT.java b/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4HeadBodyIsEmptyIT.java
index 1593488701e26..b4b15c22258de 100644
--- a/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4HeadBodyIsEmptyIT.java
+++ b/modules/transport-netty4/src/javaRestTest/java/org/opensearch/rest/Netty4HeadBodyIsEmptyIT.java
@@ -34,8 +34,7 @@
 
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.hamcrest.Matcher;
 
@@ -45,8 +44,8 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.hamcrest.Matchers.greaterThan;
 
 public class Netty4HeadBodyIsEmptyIT extends OpenSearchRestTestCase {
@@ -68,7 +67,7 @@ private void createTestDoc(final String indexName) throws IOException {
             }
             builder.endObject();
             Request request = new Request("PUT", "/" + indexName + "/_doc/" + "1");
-            request.setJsonEntity(Strings.toString(builder));
+            request.setJsonEntity(builder.toString());
             client().performRequest(request);
         }
     }
@@ -109,7 +108,7 @@ public void testAliasExists() throws IOException {
             builder.endObject();
 
             Request request = new Request("POST", "/_aliases");
-            request.setJsonEntity(Strings.toString(builder));
+            request.setJsonEntity(builder.toString());
             client().performRequest(request);
             headTestCase("/_alias/test_alias", emptyMap(), greaterThan(0));
             headTestCase("/test/_alias/test_alias", emptyMap(), greaterThan(0));
@@ -136,7 +135,7 @@ public void testTemplateExists() throws IOException {
             builder.endObject();
 
             Request request = new Request("PUT", "/_template/template");
-            request.setJsonEntity(Strings.toString(builder));
+            request.setJsonEntity(builder.toString());
             client().performRequest(request);
             headTestCase("/_template/template", emptyMap(), greaterThan(0));
         }
@@ -163,7 +162,7 @@ public void testGetSourceAction() throws IOException {
             builder.endObject();
 
             Request request = new Request("PUT", "/test-no-source");
-            request.setJsonEntity(Strings.toString(builder));
+            request.setJsonEntity(builder.toString());
             client().performRequest(request);
             createTestDoc("test-no-source");
             headTestCase("/test-no-source/_source/1", emptyMap(), NOT_FOUND.getStatus(), greaterThan(0));
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpChannel.java
index 66d60032d11a8..5bfb7976c6e18 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpChannel.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.channel.Channel;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.transport.netty4.Netty4TcpChannel;
 
 import java.net.InetSocketAddress;
 
+import io.netty.channel.Channel;
+
 public class Netty4HttpChannel implements HttpChannel {
 
     private final Channel channel;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandler.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandler.java
index af975518e087e..1200dcaf9e0f8 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandler.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandler.java
@@ -32,9 +32,6 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.channel.ChannelDuplexHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.http.HttpPipelinedRequest;
@@ -44,6 +41,10 @@
 import java.nio.channels.ClosedChannelException;
 import java.util.List;
 
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+
 /**
  * Implements HTTP pipelining ordering, ensuring that responses are completely served in the same order as their corresponding requests.
  */
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequest.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequest.java
index 8ce3af0bb141c..7d937157c1034 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequest.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequest.java
@@ -32,21 +32,10 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.DefaultHttpHeaders;
-import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaders;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.cookie.Cookie;
-import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
-import io.netty.handler.codec.http.cookie.ServerCookieEncoder;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.transport.netty4.Netty4Utils;
 
 import java.util.AbstractMap;
@@ -58,6 +47,18 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.DefaultHttpHeaders;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.cookie.Cookie;
+import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
+import io.netty.handler.codec.http.cookie.ServerCookieEncoder;
+
 public class Netty4HttpRequest implements HttpRequest {
 
     private final FullHttpRequest request;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestCreator.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestCreator.java
index 52d202f45a728..f97c2059e03d5 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestCreator.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestCreator.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.http.netty4;
 
+import org.opensearch.ExceptionsHelper;
+
+import java.util.List;
+
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.handler.codec.http.FullHttpRequest;
-import org.opensearch.ExceptionsHelper;
-
-import java.util.List;
 
 @ChannelHandler.Sharable
 class Netty4HttpRequestCreator extends MessageToMessageDecoder<FullHttpRequest> {
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestHandler.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestHandler.java
index caa80587a6e56..1f7aaf17d2191 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestHandler.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpRequestHandler.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.http.netty4;
 
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.http.HttpPipelinedRequest;
+
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.http.HttpPipelinedRequest;
 
 @ChannelHandler.Sharable
 class Netty4HttpRequestHandler extends SimpleChannelInboundHandler<HttpPipelinedRequest> {
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponse.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponse.java
index 78df964ce9cac..83284230be049 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponse.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponse.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.http.netty4;
 
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.http.HttpResponse;
+import org.opensearch.transport.netty4.Netty4Utils;
+
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.http.HttpResponse;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.transport.netty4.Netty4Utils;
 
 public class Netty4HttpResponse extends DefaultFullHttpResponse implements HttpResponse {
 
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponseCreator.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponseCreator.java
index 00c3049162270..e2f04f76e6af8 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponseCreator.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpResponseCreator.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.http.netty4;
 
+import org.opensearch.common.Booleans;
+import org.opensearch.transport.NettyAllocator;
+
+import java.util.List;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
@@ -41,10 +46,6 @@
 import io.netty.handler.codec.http.DefaultHttpResponse;
 import io.netty.handler.codec.http.DefaultLastHttpContent;
 import io.netty.handler.codec.http.HttpResponse;
-import org.opensearch.common.Booleans;
-import org.opensearch.transport.NettyAllocator;
-
-import java.util.List;
 
 /**
  * Split up large responses to prevent batch compression {@link JdkZlibEncoder} down the pipeline.
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerChannel.java
index 560b7b565fa40..7b8858174e555 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerChannel.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.channel.Channel;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.http.HttpServerChannel;
 import org.opensearch.transport.netty4.Netty4TcpChannel;
 
 import java.net.InetSocketAddress;
 
+import io.netty.channel.Channel;
+
 public class Netty4HttpServerChannel implements HttpServerChannel {
 
     private final Channel channel;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerTransport.java b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerTransport.java
index decab45ffca38..ededfdf27e42b 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerTransport.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4HttpServerTransport.java
@@ -32,26 +32,6 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.bootstrap.ServerBootstrap;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelOption;
-import io.netty.channel.FixedRecvByteBufAllocator;
-import io.netty.channel.RecvByteBufAllocator;
-import io.netty.channel.socket.nio.NioChannelOption;
-import io.netty.handler.codec.ByteToMessageDecoder;
-import io.netty.handler.codec.http.HttpContentCompressor;
-import io.netty.handler.codec.http.HttpContentDecompressor;
-import io.netty.handler.codec.http.HttpObjectAggregator;
-import io.netty.handler.codec.http.HttpRequestDecoder;
-import io.netty.handler.codec.http.HttpResponseEncoder;
-import io.netty.handler.timeout.ReadTimeoutException;
-import io.netty.handler.timeout.ReadTimeoutHandler;
-import io.netty.util.AttributeKey;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
@@ -60,18 +40,19 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.core.internal.net.NetUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.common.util.net.NetUtils;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.AbstractHttpServerTransport;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpHandlingSettings;
 import org.opensearch.http.HttpReadTimeoutException;
 import org.opensearch.http.HttpServerChannel;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.NettyAllocator;
 import org.opensearch.transport.NettyByteBufSizer;
@@ -82,6 +63,27 @@
 import java.net.SocketOption;
 import java.util.concurrent.TimeUnit;
 
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.FixedRecvByteBufAllocator;
+import io.netty.channel.RecvByteBufAllocator;
+import io.netty.channel.socket.nio.NioChannelOption;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.http.HttpContentCompressor;
+import io.netty.handler.codec.http.HttpContentDecompressor;
+import io.netty.handler.codec.http.HttpObjectAggregator;
+import io.netty.handler.codec.http.HttpRequestDecoder;
+import io.netty.handler.codec.http.HttpResponseEncoder;
+import io.netty.handler.timeout.ReadTimeoutException;
+import io.netty.handler.timeout.ReadTimeoutHandler;
+import io.netty.util.AttributeKey;
+
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_MAX_CHUNK_SIZE;
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_MAX_CONTENT_LENGTH;
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_MAX_HEADER_SIZE;
@@ -173,9 +175,10 @@ public Netty4HttpServerTransport(
         NamedXContentRegistry xContentRegistry,
         Dispatcher dispatcher,
         ClusterSettings clusterSettings,
-        SharedGroupFactory sharedGroupFactory
+        SharedGroupFactory sharedGroupFactory,
+        Tracer tracer
     ) {
-        super(settings, networkService, bigArrays, threadPool, xContentRegistry, dispatcher, clusterSettings);
+        super(settings, networkService, bigArrays, threadPool, xContentRegistry, dispatcher, clusterSettings, tracer);
         Netty4Utils.setAvailableProcessors(OpenSearchExecutors.NODE_PROCESSORS_SETTING.get(settings));
         NettyAllocator.logAllocatorDescriptionIfNeeded();
         this.sharedGroupFactory = sharedGroupFactory;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesServerSocketChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesServerSocketChannel.java
index c98cfbe711821..07dedb744ff11 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesServerSocketChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesServerSocketChannel.java
@@ -46,14 +46,15 @@
 
 package org.opensearch.transport;
 
-import io.netty.channel.socket.nio.NioServerSocketChannel;
-import io.netty.util.internal.SocketUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 import java.nio.channels.SocketChannel;
 import java.util.List;
 
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.util.internal.SocketUtils;
+
 /**
  * This class is adapted from {@link NioServerSocketChannel} class in the Netty project. It overrides the
  * channel read messages behavior to ensure that a {@link CopyBytesSocketChannel} socket channel is created.
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesSocketChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesSocketChannel.java
index 9a5459a5ab572..b73f74d187a2a 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesSocketChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/CopyBytesSocketChannel.java
@@ -46,18 +46,19 @@
 
 package org.opensearch.transport;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelOutboundBuffer;
-import io.netty.channel.RecvByteBufAllocator;
-import io.netty.channel.socket.nio.NioSocketChannel;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SocketChannel;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelOutboundBuffer;
+import io.netty.channel.RecvByteBufAllocator;
+import io.netty.channel.socket.nio.NioSocketChannel;
+
 import static io.netty.channel.internal.ChannelUtils.MAX_BYTES_PER_GATHERING_WRITE_ATTEMPTED_LOW_THRESHOLD;
 
 /**
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioServerSocketChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioServerSocketChannel.java
new file mode 100644
index 0000000000000..e7626b6ddc57a
--- /dev/null
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioServerSocketChannel.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.transport;
+
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.nio.channels.spi.SelectorProvider;
+import java.util.List;
+
+import io.netty.channel.socket.InternetProtocolFamily;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.util.internal.SocketUtils;
+import io.netty.util.internal.logging.InternalLogger;
+import io.netty.util.internal.logging.InternalLoggerFactory;
+
+public class Netty4NioServerSocketChannel extends NioServerSocketChannel {
+    private static final InternalLogger logger = InternalLoggerFactory.getInstance(Netty4NioServerSocketChannel.class);
+
+    public Netty4NioServerSocketChannel() {
+        super();
+    }
+
+    public Netty4NioServerSocketChannel(SelectorProvider provider) {
+        super(provider);
+    }
+
+    public Netty4NioServerSocketChannel(SelectorProvider provider, InternetProtocolFamily family) {
+        super(provider, family);
+    }
+
+    public Netty4NioServerSocketChannel(ServerSocketChannel channel) {
+        super(channel);
+    }
+
+    @Override
+    protected int doReadMessages(List<Object> buf) throws Exception {
+        SocketChannel ch = SocketUtils.accept(javaChannel());
+
+        try {
+            if (ch != null) {
+                buf.add(new Netty4NioSocketChannel(this, ch));
+                return 1;
+            }
+        } catch (Throwable t) {
+            logger.warn("Failed to create a new channel from an accepted socket.", t);
+
+            try {
+                ch.close();
+            } catch (Throwable t2) {
+                logger.warn("Failed to close a socket.", t2);
+            }
+        }
+
+        return 0;
+    }
+}
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioSocketChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioSocketChannel.java
index 9fe5d3731eb7d..cca099b4810b3 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioSocketChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4NioSocketChannel.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.transport;
 
+import java.nio.channels.SocketChannel;
+
 import io.netty.channel.Channel;
 import io.netty.channel.socket.nio.NioSocketChannel;
 
-import java.nio.channels.SocketChannel;
-
 /**
  * Helper class to expose {@link #javaChannel()} method
  */
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4Plugin.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4Plugin.java
index 73cfe4e46fbda..885315bcc1f3c 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4Plugin.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4Plugin.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.transport;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
@@ -42,12 +41,14 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.netty4.Netty4HttpServerTransport;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.netty4.Netty4Transport;
 
@@ -95,7 +96,8 @@ public Map<String, Supplier<Transport>> getTransports(
         PageCacheRecycler pageCacheRecycler,
         CircuitBreakerService circuitBreakerService,
         NamedWriteableRegistry namedWriteableRegistry,
-        NetworkService networkService
+        NetworkService networkService,
+        Tracer tracer
     ) {
         return Collections.singletonMap(
             NETTY_TRANSPORT_NAME,
@@ -107,7 +109,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 pageCacheRecycler,
                 namedWriteableRegistry,
                 circuitBreakerService,
-                getSharedGroupFactory(settings)
+                getSharedGroupFactory(settings),
+                tracer
             )
         );
     }
@@ -122,7 +125,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
         NamedXContentRegistry xContentRegistry,
         NetworkService networkService,
         HttpServerTransport.Dispatcher dispatcher,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         return Collections.singletonMap(
             NETTY_HTTP_TRANSPORT_NAME,
@@ -134,7 +138,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
                 xContentRegistry,
                 dispatcher,
                 clusterSettings,
-                getSharedGroupFactory(settings)
+                getSharedGroupFactory(settings),
+                tracer
             )
         );
     }
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyAllocator.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyAllocator.java
index e25853d864813..ff901476c162d 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyAllocator.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyAllocator.java
@@ -32,6 +32,14 @@
 
 package org.opensearch.transport;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.Booleans;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.monitor.jvm.JvmInfo;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.CompositeByteBuf;
@@ -39,14 +47,6 @@
 import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ServerChannel;
-import io.netty.channel.socket.nio.NioServerSocketChannel;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.opensearch.common.Booleans;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.monitor.jvm.JvmInfo;
-
-import java.util.concurrent.atomic.AtomicBoolean;
 
 public class NettyAllocator {
 
@@ -181,7 +181,7 @@ public static Class<? extends ServerChannel> getServerChannelType() {
         if (ALLOCATOR instanceof NoDirectBuffers) {
             return CopyBytesServerSocketChannel.class;
         } else {
-            return NioServerSocketChannel.class;
+            return Netty4NioServerSocketChannel.class;
         }
     }
 
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyByteBufSizer.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyByteBufSizer.java
index 857e07f6feca2..54824bc160747 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyByteBufSizer.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/NettyByteBufSizer.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.transport;
 
+import java.util.List;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
 
-import java.util.List;
-
 @ChannelHandler.Sharable
 public class NettyByteBufSizer extends MessageToMessageDecoder<ByteBuf> {
 
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/SharedGroupFactory.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/SharedGroupFactory.java
index d70f6bc83cc73..454293442572c 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/SharedGroupFactory.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/SharedGroupFactory.java
@@ -32,9 +32,6 @@
 
 package org.opensearch.transport;
 
-import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
-import io.netty.util.concurrent.Future;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.settings.Settings;
@@ -46,6 +43,10 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.util.concurrent.Future;
+
 import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
 
 /**
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4MessageChannelHandler.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4MessageChannelHandler.java
index ad2e287f7a28d..7b9999ce5b20e 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4MessageChannelHandler.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4MessageChannelHandler.java
@@ -32,18 +32,12 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelDuplexHandler;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.OpenSearchException;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.InboundPipeline;
 import org.opensearch.transport.Transport;
@@ -53,6 +47,13 @@
 import java.util.ArrayDeque;
 import java.util.Queue;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+
 /**
  * A handler (must be the last one!) that does size based frame decoding and forwards the actual message
  * to the relevant action.
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpChannel.java
index eeee0ff33e792..5db1f7c333157 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpChannel.java
@@ -32,19 +32,20 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelPromise;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.transport.TcpChannel;
 import org.opensearch.transport.TransportException;
 
 import java.net.InetSocketAddress;
 
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelPromise;
+
 public class Netty4TcpChannel implements TcpChannel {
 
     private final Channel channel;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpServerChannel.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpServerChannel.java
index 6131d7fe2acb9..8910e2b51374e 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpServerChannel.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4TcpServerChannel.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.channel.Channel;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.transport.TcpServerChannel;
 
 import java.net.InetSocketAddress;
 
+import io.netty.channel.Channel;
+
 public class Netty4TcpServerChannel implements TcpServerChannel {
 
     private final Channel channel;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Transport.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Transport.java
index 45bd5464485d5..e76a227630dc1 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Transport.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Transport.java
@@ -31,20 +31,6 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.bootstrap.Bootstrap;
-import io.netty.bootstrap.ServerBootstrap;
-import io.netty.channel.AdaptiveRecvByteBufAllocator;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelOption;
-import io.netty.channel.FixedRecvByteBufAllocator;
-import io.netty.channel.RecvByteBufAllocator;
-import io.netty.channel.socket.nio.NioChannelOption;
-import io.netty.util.AttributeKey;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -52,18 +38,19 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.core.internal.net.NetUtils;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.common.util.net.NetUtils;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Netty4NioSocketChannel;
 import org.opensearch.transport.NettyAllocator;
@@ -77,6 +64,21 @@
 import java.net.SocketOption;
 import java.util.Map;
 
+import io.netty.bootstrap.Bootstrap;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.channel.AdaptiveRecvByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.FixedRecvByteBufAllocator;
+import io.netty.channel.RecvByteBufAllocator;
+import io.netty.channel.socket.nio.NioChannelOption;
+import io.netty.util.AttributeKey;
+
 import static org.opensearch.common.settings.Setting.byteSizeSetting;
 import static org.opensearch.common.settings.Setting.intSetting;
 import static org.opensearch.common.util.concurrent.ConcurrentCollections.newConcurrentMap;
@@ -130,9 +132,10 @@ public Netty4Transport(
         PageCacheRecycler pageCacheRecycler,
         NamedWriteableRegistry namedWriteableRegistry,
         CircuitBreakerService circuitBreakerService,
-        SharedGroupFactory sharedGroupFactory
+        SharedGroupFactory sharedGroupFactory,
+        Tracer tracer
     ) {
-        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService);
+        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService, tracer);
         Netty4Utils.setAvailableProcessors(OpenSearchExecutors.NODE_PROCESSORS_SETTING.get(settings));
         NettyAllocator.logAllocatorDescriptionIfNeeded();
         this.sharedGroupFactory = sharedGroupFactory;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Utils.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Utils.java
index e13329b8c2593..11fc74a2afa7f 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Utils.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/netty4/Netty4Utils.java
@@ -32,15 +32,11 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.CompositeByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.util.NettyRuntime;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -49,6 +45,11 @@
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.util.NettyRuntime;
+
 public class Netty4Utils {
 
     private static final AtomicBoolean isAvailableProcessorsSet = new AtomicBoolean();
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4BadRequestTests.java b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4BadRequestTests.java
index a0100930c7dcb..492da422382ce 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4BadRequestTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4BadRequestTests.java
@@ -32,23 +32,22 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.util.ReferenceCounted;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpTransportSettings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -61,6 +60,9 @@
 import java.util.Collection;
 import java.util.Collections;
 
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.util.ReferenceCounted;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
@@ -111,7 +113,8 @@ public void dispatchBadRequest(RestChannel channel, ThreadContext threadContext,
                 xContentRegistry(),
                 dispatcher,
                 new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
-                new SharedGroupFactory(Settings.EMPTY)
+                new SharedGroupFactory(Settings.EMPTY),
+                NoopTracer.INSTANCE
             )
         ) {
             httpServerTransport.start();
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpClient.java b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpClient.java
index 57f95a022a33f..1a9f2a558ecd8 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpClient.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpClient.java
@@ -32,6 +32,22 @@
 
 package org.opensearch.http.netty4;
 
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.tasks.Task;
+import org.opensearch.transport.NettyAllocator;
+
+import java.io.Closeable;
+import java.net.SocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
 import io.netty.bootstrap.Bootstrap;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -55,21 +71,6 @@
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.HttpResponseDecoder;
 import io.netty.handler.codec.http.HttpVersion;
-import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.tasks.Task;
-import org.opensearch.transport.NettyAllocator;
-
-import java.io.Closeable;
-import java.net.SocketAddress;
-import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
 
 import static io.netty.handler.codec.http.HttpHeaderNames.HOST;
 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandlerTests.java b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandlerTests.java
index d37e28dabf19d..743b51e979fb7 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandlerTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpPipeliningHandlerTests.java
@@ -32,22 +32,13 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.buffer.ByteBufUtil;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.QueryStringDecoder;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpPipelinedRequest;
 import org.opensearch.http.HttpPipelinedResponse;
 import org.opensearch.http.HttpResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 
@@ -64,9 +55,19 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import io.netty.buffer.ByteBufUtil;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.QueryStringDecoder;
+
+import static org.hamcrest.core.Is.is;
 import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
-import static org.hamcrest.core.Is.is;
 
 public class Netty4HttpPipeliningHandlerTests extends OpenSearchTestCase {
 
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerPipeliningTests.java b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerPipeliningTests.java
index 029aed1f3cc89..9bca90c3a408a 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerPipeliningTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerPipeliningTests.java
@@ -32,28 +32,20 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.util.ReferenceCounted;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpPipelinedRequest;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.NullDispatcher;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -69,6 +61,16 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.util.ReferenceCounted;
+
 import static org.hamcrest.Matchers.contains;
 
 /**
@@ -134,7 +136,8 @@ class CustomNettyHttpServerTransport extends Netty4HttpServerTransport {
                 xContentRegistry(),
                 new NullDispatcher(),
                 new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
-                new SharedGroupFactory(settings)
+                new SharedGroupFactory(settings),
+                NoopTracer.INSTANCE
             );
         }
 
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerTransportTests.java b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerTransportTests.java
index ec879e538fe20..2bdb95389e737 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerTransportTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpServerTransportTests.java
@@ -32,59 +32,36 @@
 
 package org.opensearch.http.netty4;
 
-import io.netty.bootstrap.Bootstrap;
-import io.netty.buffer.ByteBufAllocator;
-import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.PoolArenaMetric;
-import io.netty.buffer.PooledByteBufAllocator;
-import io.netty.buffer.PooledByteBufAllocatorMetric;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandlerAdapter;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelOption;
-import io.netty.channel.nio.NioEventLoopGroup;
-import io.netty.channel.socket.SocketChannel;
-import io.netty.channel.socket.nio.NioSocketChannel;
-import io.netty.handler.codec.TooLongFrameException;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaderValues;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.handler.codec.http.HttpUtil;
-import io.netty.handler.codec.http.HttpVersion;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.http.BindHttpException;
 import org.opensearch.http.CorsHandler;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpTransportSettings;
 import org.opensearch.http.NullDispatcher;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.SharedGroupFactory;
 import org.opensearch.transport.NettyAllocator;
+import org.opensearch.transport.SharedGroupFactory;
 import org.junit.After;
 import org.junit.Before;
 
@@ -96,10 +73,35 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
+import io.netty.bootstrap.Bootstrap;
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.buffer.ByteBufUtil;
+import io.netty.buffer.PoolArenaMetric;
+import io.netty.buffer.PooledByteBufAllocator;
+import io.netty.buffer.PooledByteBufAllocatorMetric;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioSocketChannel;
+import io.netty.handler.codec.TooLongFrameException;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaderValues;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.HttpUtil;
+import io.netty.handler.codec.http.HttpVersion;
+
+import static org.opensearch.core.rest.RestStatus.BAD_REQUEST;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ALLOW_ORIGIN;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ENABLED;
-import static org.opensearch.rest.RestStatus.BAD_REQUEST;
-import static org.opensearch.rest.RestStatus.OK;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
@@ -197,7 +199,8 @@ public void dispatchBadRequest(RestChannel channel, ThreadContext threadContext,
                 xContentRegistry(),
                 dispatcher,
                 clusterSettings,
-                new SharedGroupFactory(settings)
+                new SharedGroupFactory(settings),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -246,7 +249,8 @@ public void testBindUnavailableAddress() {
                 xContentRegistry(),
                 new NullDispatcher(),
                 clusterSettings,
-                new SharedGroupFactory(Settings.EMPTY)
+                new SharedGroupFactory(Settings.EMPTY),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -264,7 +268,8 @@ public void testBindUnavailableAddress() {
                     xContentRegistry(),
                     new NullDispatcher(),
                     clusterSettings,
-                    new SharedGroupFactory(settings)
+                    new SharedGroupFactory(settings),
+                    NoopTracer.INSTANCE
                 )
             ) {
                 BindHttpException bindHttpException = expectThrows(BindHttpException.class, otherTransport::start);
@@ -316,7 +321,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 clusterSettings,
-                new SharedGroupFactory(settings)
+                new SharedGroupFactory(settings),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -378,7 +384,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 clusterSettings,
-                new SharedGroupFactory(Settings.EMPTY)
+                new SharedGroupFactory(Settings.EMPTY),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -447,7 +454,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
-                new SharedGroupFactory(settings)
+                new SharedGroupFactory(settings),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -520,7 +528,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
-                new SharedGroupFactory(settings)
+                new SharedGroupFactory(settings),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/transport/CopyBytesSocketChannelTests.java b/modules/transport-netty4/src/test/java/org/opensearch/transport/CopyBytesSocketChannelTests.java
index 7cb4225f02293..2ace9b111a64b 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/transport/CopyBytesSocketChannelTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/transport/CopyBytesSocketChannelTests.java
@@ -31,18 +31,6 @@
 
 package org.opensearch.transport;
 
-import io.netty.bootstrap.Bootstrap;
-import io.netty.bootstrap.ServerBootstrap;
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.buffer.UnpooledByteBufAllocator;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelOption;
-import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.nio.NioEventLoopGroup;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -57,6 +45,19 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
+import io.netty.bootstrap.Bootstrap;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.buffer.UnpooledByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.nio.NioEventLoopGroup;
+
 public class CopyBytesSocketChannelTests extends OpenSearchTestCase {
 
     private final UnpooledByteBufAllocator alloc = new UnpooledByteBufAllocator(false);
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4SizeHeaderFrameDecoderTests.java b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4SizeHeaderFrameDecoderTests.java
index cd263a20c9a74..c92ccba82835f 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4SizeHeaderFrameDecoderTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4SizeHeaderFrameDecoderTests.java
@@ -33,13 +33,14 @@
 package org.opensearch.transport.netty4;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.SharedGroupFactory;
@@ -86,7 +87,8 @@ public void startThreadPool() {
             recycler,
             new NamedWriteableRegistry(Collections.emptyList()),
             new NoneCircuitBreakerService(),
-            new SharedGroupFactory(settings)
+            new SharedGroupFactory(settings),
+            NoopTracer.INSTANCE
         );
         nettyTransport.start();
 
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4UtilsTests.java b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4UtilsTests.java
index 6aafd78ab2f2c..296f9aa3901c6 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4UtilsTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/Netty4UtilsTests.java
@@ -32,22 +32,23 @@
 
 package org.opensearch.transport.netty4;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.CompositeByteBuf;
-import io.netty.buffer.Unpooled;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.bytes.AbstractBytesReferenceTestCase;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.buffer.Unpooled;
+
 public class Netty4UtilsTests extends OpenSearchTestCase {
 
     private static final int PAGE_SIZE = PageCacheRecycler.BYTE_PAGE_SIZE;
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/NettyTransportMultiPortTests.java b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/NettyTransportMultiPortTests.java
index 78a3a353fbf2f..7cca00db68559 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/NettyTransportMultiPortTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/NettyTransportMultiPortTests.java
@@ -32,14 +32,15 @@
 package org.opensearch.transport.netty4;
 
 import org.opensearch.Version;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -141,7 +142,8 @@ private TcpTransport startTransport(Settings settings, ThreadPool threadPool) {
             recycler,
             new NamedWriteableRegistry(Collections.emptyList()),
             new NoneCircuitBreakerService(),
-            new SharedGroupFactory(settings)
+            new SharedGroupFactory(settings),
+            NoopTracer.INSTANCE
         );
         transport.start();
 
diff --git a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/SimpleNetty4TransportTests.java b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/SimpleNetty4TransportTests.java
index b690ba9e35e35..710b3ff6bd0ca 100644
--- a/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/SimpleNetty4TransportTests.java
+++ b/modules/transport-netty4/src/test/java/org/opensearch/transport/netty4/SimpleNetty4TransportTests.java
@@ -33,18 +33,18 @@
 package org.opensearch.transport.netty4;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.core.internal.net.NetUtils;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.common.util.net.NetUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.test.transport.StubbableTransport;
 import org.opensearch.transport.AbstractSimpleTransportTestCase;
@@ -83,7 +83,8 @@ protected Transport build(Settings settings, final Version version, ClusterSetti
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             namedWriteableRegistry,
             new NoneCircuitBreakerService(),
-            new SharedGroupFactory(settings)
+            new SharedGroupFactory(settings),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -121,10 +122,7 @@ public void testConnectException() throws UnknownHostException {
     }
 
     public void testDefaultKeepAliveSettings() throws IOException {
-        assumeTrue(
-            "setting default keepalive options not supported on this platform",
-            (IOUtils.LINUX || IOUtils.MAC_OS_X) && JavaVersion.current().compareTo(JavaVersion.parse("11")) >= 0
-        );
+        assumeTrue("setting default keepalive options not supported on this platform", (IOUtils.LINUX || IOUtils.MAC_OS_X));
         try (
             MockTransportService serviceC = buildService("TS_C", Version.CURRENT, Settings.EMPTY);
             MockTransportService serviceD = buildService("TS_D", Version.CURRENT, Settings.EMPTY)
diff --git a/modules/transport-netty4/src/yamlRestTest/resources/rest-api-spec/test/10_basic.yml b/modules/transport-netty4/src/yamlRestTest/resources/rest-api-spec/test/10_basic.yml
index 19728c7d34cff..f4ac484757a41 100644
--- a/modules/transport-netty4/src/yamlRestTest/resources/rest-api-spec/test/10_basic.yml
+++ b/modules/transport-netty4/src/yamlRestTest/resources/rest-api-spec/test/10_basic.yml
@@ -7,13 +7,13 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.modules: { name: transport-netty4  } }
+    - contains:  { nodes.$cluster_manager.modules: { name: transport-netty4  } }
 
     - do:
         cluster.stats: {}
diff --git a/plugins/analysis-icu/licenses/lucene-analysis-icu-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-icu/licenses/lucene-analysis-icu-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 2f0a6ad50e337..0000000000000
--- a/plugins/analysis-icu/licenses/lucene-analysis-icu-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-77930f802430648980eded22ca6ed47fedaeaba4
\ No newline at end of file
diff --git a/plugins/analysis-icu/licenses/lucene-analysis-icu-9.7.0.jar.sha1 b/plugins/analysis-icu/licenses/lucene-analysis-icu-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..0ed030926ab93
--- /dev/null
+++ b/plugins/analysis-icu/licenses/lucene-analysis-icu-9.7.0.jar.sha1
@@ -0,0 +1 @@
+94293b169fb8572f440a5a4a523320ecf9778ffe
\ No newline at end of file
diff --git a/plugins/analysis-icu/src/internalClusterTest/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperIT.java b/plugins/analysis-icu/src/internalClusterTest/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperIT.java
index 4735f39033081..9ef539caf24f9 100644
--- a/plugins/analysis-icu/src/internalClusterTest/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperIT.java
+++ b/plugins/analysis-icu/src/internalClusterTest/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperIT.java
@@ -31,19 +31,13 @@
 
 package org.opensearch.index.mapper;
 
-import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertOrderedSearchHits;
-
 import com.ibm.icu.text.Collator;
 import com.ibm.icu.text.RuleBasedCollator;
 import com.ibm.icu.util.ULocale;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.plugins.Plugin;
@@ -56,6 +50,12 @@
 import java.util.Collection;
 import java.util.Collections;
 
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertOrderedSearchHits;
+
 public class ICUCollationKeywordFieldMapperIT extends OpenSearchIntegTestCase {
 
     @Override
@@ -91,8 +91,12 @@ public void testBasicUsage() throws Exception {
         // both values should collate to same value
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", XContentType.JSON)
+            client().prepareIndex(index)
+                .setId("1")
+                .setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", MediaTypeRegistry.JSON)
         );
 
         // searching for either of the terms should return both results since they collate to the same value
@@ -134,8 +138,10 @@ public void testMultipleValues() throws Exception {
             true,
             client().prepareIndex(index)
                 .setId("1")
-                .setSource("{\"id\":\"1\", \"collate\":[\"" + equivalent[0] + "\", \"" + equivalent[1] + "\"]}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[2] + "\"}", XContentType.JSON)
+                .setSource("{\"id\":\"1\", \"collate\":[\"" + equivalent[0] + "\", \"" + equivalent[1] + "\"]}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[2] + "\"}", MediaTypeRegistry.JSON)
         );
 
         // using sort mode = max, values B and C will be used for the sort
@@ -195,8 +201,12 @@ public void testNormalization() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", XContentType.JSON)
+            client().prepareIndex(index)
+                .setId("1")
+                .setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", MediaTypeRegistry.JSON)
         );
 
         // searching for either of the terms should return both results since they collate to the same value
@@ -240,8 +250,12 @@ public void testSecondaryStrength() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", XContentType.JSON)
+            client().prepareIndex(index)
+                .setId("1")
+                .setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -285,8 +299,12 @@ public void testIgnorePunctuation() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", XContentType.JSON)
+            client().prepareIndex(index)
+                .setId("1")
+                .setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -330,9 +348,9 @@ public void testIgnoreWhitespace() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"foo bar\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"foobar\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("3").setSource("{\"id\":\"3\",\"collate\":\"foo-bar\"}", XContentType.JSON)
+            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"foo bar\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"foobar\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("3").setSource("{\"id\":\"3\",\"collate\":\"foo-bar\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -372,8 +390,8 @@ public void testNumerics() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"collate\":\"foobar-10\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"collate\":\"foobar-9\"}", XContentType.JSON)
+            client().prepareIndex(index).setId("1").setSource("{\"collate\":\"foobar-10\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("2").setSource("{\"collate\":\"foobar-9\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -411,10 +429,10 @@ public void testIgnoreAccentsButNotCase() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"résumé\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"Resume\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("3").setSource("{\"id\":\"3\",\"collate\":\"resume\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("4").setSource("{\"id\":\"4\",\"collate\":\"Résumé\"}", XContentType.JSON)
+            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"résumé\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"Resume\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("3").setSource("{\"id\":\"3\",\"collate\":\"resume\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("4").setSource("{\"id\":\"4\",\"collate\":\"Résumé\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -449,8 +467,8 @@ public void testUpperCaseFirst() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"collate\":\"resume\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"collate\":\"Resume\"}", XContentType.JSON)
+            client().prepareIndex(index).setId("1").setSource("{\"collate\":\"resume\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index).setId("2").setSource("{\"collate\":\"Resume\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
@@ -497,8 +515,12 @@ public void testCustomRules() throws Exception {
 
         indexRandom(
             true,
-            client().prepareIndex(index).setId("1").setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", XContentType.JSON),
-            client().prepareIndex(index).setId("2").setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", XContentType.JSON)
+            client().prepareIndex(index)
+                .setId("1")
+                .setSource("{\"id\":\"1\",\"collate\":\"" + equivalent[0] + "\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex(index)
+                .setId("2")
+                .setSource("{\"id\":\"2\",\"collate\":\"" + equivalent[1] + "\"}", MediaTypeRegistry.JSON)
         );
 
         SearchRequest request = new SearchRequest().indices(index)
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/ICUCollationKeyFilter.java b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/ICUCollationKeyFilter.java
index d7e097ce79798..35e0ed7651547 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/ICUCollationKeyFilter.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/ICUCollationKeyFilter.java
@@ -34,8 +34,8 @@
 import com.ibm.icu.text.RawCollationKey;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
-import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.analysis.icu.ICUCollationDocValuesField;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 
 import java.io.IOException;
 
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuCollationTokenFilterFactory.java b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuCollationTokenFilterFactory.java
index 757a55487a162..09f4c2286faee 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuCollationTokenFilterFactory.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuCollationTokenFilterFactory.java
@@ -32,20 +32,20 @@
 
 package org.opensearch.index.analysis;
 
-import java.io.IOException;
-import java.nio.charset.Charset;
-import java.nio.file.Files;
-import java.nio.file.InvalidPathException;
-
+import com.ibm.icu.text.Collator;
+import com.ibm.icu.text.RuleBasedCollator;
+import com.ibm.icu.util.ULocale;
+import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.analysis.TokenStream;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
-import com.ibm.icu.text.Collator;
-import com.ibm.icu.text.RuleBasedCollator;
-import com.ibm.icu.util.ULocale;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
 
 /**
  * An ICU based collation token filter. There are two ways to configure collation:
@@ -80,9 +80,12 @@ public IcuCollationTokenFilterFactory(IndexSettings indexSettings, Environment e
                 collator = new RuleBasedCollator(rules);
             } catch (Exception e) {
                 if (failureToResolve != null) {
-                    throw new IllegalArgumentException("Failed to resolve collation rules location", failureToResolve);
+                    LogManager.getLogger(IcuCollationTokenFilterFactory.class)
+                        .error("Failed to resolve collation rules location", failureToResolve);
+                    throw new IllegalArgumentException("Failed to resolve collation rules location");
                 } else {
-                    throw new IllegalArgumentException("Failed to parse collation rules", e);
+                    LogManager.getLogger(IcuCollationTokenFilterFactory.class).error("Failed to parse collation rules", e);
+                    throw new IllegalArgumentException("Failed to parse collation rules");
                 }
             }
         } else {
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuFoldingTokenFilterFactory.java b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuFoldingTokenFilterFactory.java
index 605d5065edec9..d0c809fba1f86 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuFoldingTokenFilterFactory.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuFoldingTokenFilterFactory.java
@@ -33,7 +33,6 @@
 package org.opensearch.index.analysis;
 
 import com.ibm.icu.text.Normalizer2;
-
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.icu.ICUFoldingFilter;
 import org.opensearch.common.settings.Settings;
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuNormalizerCharFilterFactory.java b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuNormalizerCharFilterFactory.java
index 754c52ad5dfe6..e6e21232d17f8 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuNormalizerCharFilterFactory.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/index/analysis/IcuNormalizerCharFilterFactory.java
@@ -33,7 +33,6 @@
 package org.opensearch.index.analysis;
 
 import com.ibm.icu.text.Normalizer2;
-
 import org.apache.lucene.analysis.icu.ICUNormalizer2CharFilter;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapper.java b/plugins/analysis-icu/src/main/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapper.java
index 59b01b0ddb466..bd9c164811093 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapper.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapper.java
@@ -44,12 +44,12 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.IndexableBinaryStringTools;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
diff --git a/plugins/analysis-icu/src/main/java/org/opensearch/plugin/analysis/icu/AnalysisICUPlugin.java b/plugins/analysis-icu/src/main/java/org/opensearch/plugin/analysis/icu/AnalysisICUPlugin.java
index 1f9d7d7463fbd..7a61d1400c217 100644
--- a/plugins/analysis-icu/src/main/java/org/opensearch/plugin/analysis/icu/AnalysisICUPlugin.java
+++ b/plugins/analysis-icu/src/main/java/org/opensearch/plugin/analysis/icu/AnalysisICUPlugin.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.plugin.analysis.icu;
 
-import static java.util.Collections.singletonMap;
-
 import org.apache.lucene.analysis.Analyzer;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.index.analysis.AnalyzerProvider;
 import org.opensearch.index.analysis.CharFilterFactory;
 import org.opensearch.index.analysis.IcuAnalyzerProvider;
@@ -60,6 +58,8 @@
 import java.util.List;
 import java.util.Map;
 
+import static java.util.Collections.singletonMap;
+
 public class AnalysisICUPlugin extends Plugin implements AnalysisPlugin, MapperPlugin {
     @Override
     public Map<String, AnalysisProvider<CharFilterFactory>> getCharFilters() {
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuAnalyzerTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuAnalyzerTests.java
index e490248fc8122..c363bc6eb43f8 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuAnalyzerTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuAnalyzerTests.java
@@ -90,10 +90,9 @@ public void testBadSettings() {
         Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).put("mode", "wrong").build();
         IndexSettings idxSettings = IndexSettingsModule.newIndexSettings("index", settings);
 
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { new IcuAnalyzerProvider(idxSettings, null, "icu", settings); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            new IcuAnalyzerProvider(idxSettings, null, "icu", settings);
+        });
 
         assertThat(e.getMessage(), containsString("Unknown mode [wrong] in analyzer [icu], expected one of [compose, decompose]"));
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuTokenizerFactoryTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuTokenizerFactoryTests.java
index 115171aec184f..6062aaced9dea 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuTokenizerFactoryTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IcuTokenizerFactoryTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IndexableBinaryStringToolsTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IndexableBinaryStringToolsTests.java
index 63e21b2f7903b..d11a09069b71c 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IndexableBinaryStringToolsTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/IndexableBinaryStringToolsTests.java
@@ -34,9 +34,10 @@
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope;
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope.Scope;
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
-import org.apache.lucene.util.ArrayUtil;
+
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.apache.lucene.tests.util.TimeUnits;
+import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.test.junit.listeners.ReproduceInfoPrinter;
 import org.junit.BeforeClass;
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuAnalysisTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuAnalysisTests.java
index b7f42d524dbe8..2a5268d0c0d9d 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuAnalysisTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuAnalysisTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.analysis;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuCollationTokenFilterTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuCollationTokenFilterTests.java
index a7bd2ca5a0440..980fcc6deb837 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuCollationTokenFilterTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuCollationTokenFilterTests.java
@@ -40,7 +40,7 @@
 import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuNormalizerCharFilterTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuNormalizerCharFilterTests.java
index 4ba8a6ca0b1f1..9bfa997badaad 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuNormalizerCharFilterTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/analysis/SimpleIcuNormalizerCharFilterTests.java
@@ -35,7 +35,7 @@
 import com.ibm.icu.text.Normalizer2;
 import org.apache.lucene.analysis.CharFilter;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/CollationFieldTypeTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/CollationFieldTypeTests.java
index 8dcec874d3771..1e08000117f61 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/CollationFieldTypeTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/CollationFieldTypeTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.index.mapper;
 
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import com.ibm.icu.text.Collator;
 import com.ibm.icu.text.RawCollationKey;
 import com.ibm.icu.util.ULocale;
diff --git a/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperTests.java b/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperTests.java
index 0cf82c408ae6f..0a2f48f4215cb 100644
--- a/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperTests.java
+++ b/plugins/analysis-icu/src/test/java/org/opensearch/index/mapper/ICUCollationKeywordFieldMapperTests.java
@@ -39,15 +39,14 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.IndexableFieldType;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.List;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugin.analysis.icu.AnalysisICUPlugin;
 import org.opensearch.plugins.Plugin;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
 
 import static org.hamcrest.Matchers.containsString;
@@ -69,7 +68,7 @@ protected ICUCollationKeywordFieldMapper.Builder newBuilder() {
 
     @Override
     protected Set<String> unsupportedProperties() {
-        return org.opensearch.common.collect.Set.of("analyzer", "similarity");
+        return Set.of("analyzer", "similarity");
     }
 
     @Override
@@ -96,7 +95,7 @@ protected void writeFieldValue(XContentBuilder builder) throws IOException {
 
     public void testDefaults() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
-        assertEquals(Strings.toString(fieldMapping(this::minimalMapping)), mapper.mappingSource().toString());
+        assertEquals(fieldMapping(this::minimalMapping).toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
         IndexableField[] fields = doc.rootDoc().getFields("field");
diff --git a/plugins/analysis-icu/src/test/resources/org/opensearch/index/analysis/KeywordTokenizer.rbbi b/plugins/analysis-icu/src/test/resources/org/opensearch/index/analysis/KeywordTokenizer.rbbi
index 8e6de8aa94abb..86eb398ee9157 100644
--- a/plugins/analysis-icu/src/test/resources/org/opensearch/index/analysis/KeywordTokenizer.rbbi
+++ b/plugins/analysis-icu/src/test/resources/org/opensearch/index/analysis/KeywordTokenizer.rbbi
@@ -18,4 +18,4 @@
 
 # Apply rule status {200}=RBBI.WORD_LETTER, which is mapped
 # to <ALPHANUM> token type by DefaultICUTokenizerConfig.
-.+ {200};
\ No newline at end of file
+.+ {200};
diff --git a/plugins/analysis-kuromoji/build.gradle b/plugins/analysis-kuromoji/build.gradle
index 60738fb28b6d5..426b85f44bf55 100644
--- a/plugins/analysis-kuromoji/build.gradle
+++ b/plugins/analysis-kuromoji/build.gradle
@@ -46,4 +46,3 @@ restResources {
 tasks.named("dependencyLicenses").configure {
   mapping from: /lucene-.*/, to: 'lucene'
 }
-
diff --git a/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index a0d112dd733ab..0000000000000
--- a/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c66f568fa9138c6ab6f3abf1efbfab3c7b5991d4
\ No newline at end of file
diff --git a/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.7.0.jar.sha1 b/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..ddd67276606a5
--- /dev/null
+++ b/plugins/analysis-kuromoji/licenses/lucene-analysis-kuromoji-9.7.0.jar.sha1
@@ -0,0 +1 @@
+2df800a38b64867b8dcd61fc2cd986114e4a80cb
\ No newline at end of file
diff --git a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiPartOfSpeechFilterFactory.java b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiPartOfSpeechFilterFactory.java
index fef8d06c466b9..8e9c209ae421d 100644
--- a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiPartOfSpeechFilterFactory.java
+++ b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiPartOfSpeechFilterFactory.java
@@ -49,7 +49,7 @@ public class KuromojiPartOfSpeechFilterFactory extends AbstractTokenFilterFactor
 
     public KuromojiPartOfSpeechFilterFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) {
         super(indexSettings, name, settings);
-        List<String> wordList = Analysis.getWordList(env, settings, "stoptags");
+        List<String> wordList = Analysis.parseWordList(env, settings, "stoptags", s -> s);
         if (wordList != null) {
             stopTags.addAll(wordList);
         } else {
diff --git a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiTokenizerFactory.java b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiTokenizerFactory.java
index b5e718eaa6fa0..2939711f6f7e1 100644
--- a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiTokenizerFactory.java
+++ b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiTokenizerFactory.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.index.analysis;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ja.JapaneseTokenizer;
 import org.apache.lucene.analysis.ja.JapaneseTokenizer.Mode;
@@ -50,6 +52,7 @@
 
 public class KuromojiTokenizerFactory extends AbstractTokenizerFactory {
 
+    private static final Logger LOGGER = LogManager.getLogger(KuromojiTokenizerFactory.class);
     private static final String USER_DICT_PATH_OPTION = "user_dictionary";
     private static final String USER_DICT_RULES_OPTION = "user_dictionary_rules";
     private static final String NBEST_COST = "nbest_cost";
@@ -74,6 +77,17 @@ public KuromojiTokenizerFactory(IndexSettings indexSettings, Environment env, St
         discardCompoundToken = settings.getAsBoolean(DISCARD_COMPOUND_TOKEN, false);
     }
 
+    private static String parse(String rule, Set<String> dup) {
+        String[] values = CSVUtil.parse(rule);
+        if (values.length == 0) {
+            throw new IllegalArgumentException("Malformed csv in user dictionary.");
+        }
+        if (dup.add(values[0]) == false) {
+            throw new IllegalArgumentException("Found duplicate term [" + values[0] + "] in user dictionary.");
+        }
+        return rule;
+    }
+
     public static UserDictionary getUserDictionary(Environment env, Settings settings) {
         if (settings.get(USER_DICT_PATH_OPTION) != null && settings.get(USER_DICT_RULES_OPTION) != null) {
             throw new IllegalArgumentException(
@@ -81,31 +95,26 @@ public static UserDictionary getUserDictionary(Environment env, Settings setting
             );
         }
         try {
-            List<String> ruleList = Analysis.getWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION, false);
+            Set<String> dup = new HashSet<>();
+            List<String> ruleList = Analysis.parseWordList(
+                env,
+                settings,
+                USER_DICT_PATH_OPTION,
+                USER_DICT_RULES_OPTION,
+                s -> parse(s, dup)
+            );
             if (ruleList == null || ruleList.isEmpty()) {
                 return null;
             }
-            Set<String> dup = new HashSet<>();
-            int lineNum = 0;
-            for (String line : ruleList) {
-                // ignore comments
-                if (line.startsWith("#") == false) {
-                    String[] values = CSVUtil.parse(line);
-                    if (dup.add(values[0]) == false) {
-                        throw new IllegalArgumentException(
-                            "Found duplicate term [" + values[0] + "] in user dictionary " + "at line [" + lineNum + "]"
-                        );
-                    }
-                }
-                ++lineNum;
-            }
+
             StringBuilder sb = new StringBuilder();
             for (String line : ruleList) {
                 sb.append(line).append(System.lineSeparator());
             }
             return UserDictionary.open(new StringReader(sb.toString()));
         } catch (IOException e) {
-            throw new OpenSearchException("failed to load kuromoji user dictionary", e);
+            LOGGER.error("Failed to load kuromoji user dictionary", e);
+            throw new OpenSearchException("Failed to load kuromoji user dictionary");
         }
     }
 
diff --git a/plugins/analysis-kuromoji/src/test/java/org/opensearch/index/analysis/KuromojiAnalysisTests.java b/plugins/analysis-kuromoji/src/test/java/org/opensearch/index/analysis/KuromojiAnalysisTests.java
index e17658d83a085..ffc2db6672899 100644
--- a/plugins/analysis-kuromoji/src/test/java/org/opensearch/index/analysis/KuromojiAnalysisTests.java
+++ b/plugins/analysis-kuromoji/src/test/java/org/opensearch/index/analysis/KuromojiAnalysisTests.java
@@ -41,8 +41,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.plugin.analysis.kuromoji.AnalysisKuromojiPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -53,12 +53,12 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 
-import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 
 public class KuromojiAnalysisTests extends OpenSearchTestCase {
     public void testDefaultsKuromojiAnalysis() throws IOException {
@@ -379,6 +379,15 @@ public void testKuromojiAnalyzerInvalidUserDictOption() throws Exception {
         );
     }
 
+    public void testKuromojiAnalyzerEmptyDictRule() throws Exception {
+        Settings settings = Settings.builder()
+            .put("index.analysis.analyzer.my_analyzer.type", "kuromoji")
+            .putList("index.analysis.analyzer.my_analyzer.user_dictionary_rules", "\"")
+            .build();
+        RuntimeException exc = expectThrows(RuntimeException.class, () -> createTestAnalysis(settings));
+        assertThat(exc.getMessage(), equalTo("Line [1]: Malformed csv in user dictionary."));
+    }
+
     public void testKuromojiAnalyzerDuplicateUserDictRule() throws Exception {
         Settings settings = Settings.builder()
             .put("index.analysis.analyzer.my_analyzer.type", "kuromoji")
@@ -390,8 +399,8 @@ public void testKuromojiAnalyzerDuplicateUserDictRule() throws Exception {
                 "制限スピード,制限スピード,セイゲンスピード,テスト名詞"
             )
             .build();
-        IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> createTestAnalysis(settings));
-        assertThat(exc.getMessage(), containsString("[制限スピード] in user dictionary at line [3]"));
+        RuntimeException exc = expectThrows(RuntimeException.class, () -> createTestAnalysis(settings));
+        assertThat(exc.getMessage(), equalTo("Line [4]: Found duplicate term [制限スピード] in user dictionary."));
     }
 
     public void testDiscardCompoundToken() throws Exception {
diff --git a/plugins/analysis-nori/licenses/lucene-analysis-nori-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-nori/licenses/lucene-analysis-nori-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index a3f939bfe9e05..0000000000000
--- a/plugins/analysis-nori/licenses/lucene-analysis-nori-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e8c47600ea859b999a5f5647341b0350b03dafcd
\ No newline at end of file
diff --git a/plugins/analysis-nori/licenses/lucene-analysis-nori-9.7.0.jar.sha1 b/plugins/analysis-nori/licenses/lucene-analysis-nori-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..0cd68af98e724
--- /dev/null
+++ b/plugins/analysis-nori/licenses/lucene-analysis-nori-9.7.0.jar.sha1
@@ -0,0 +1 @@
+a01e8153f34d72e8c8c0180c1dea5b10f677dd3a
\ No newline at end of file
diff --git a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriAnalyzerProvider.java b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriAnalyzerProvider.java
index 3dee606185429..d3c452c1f2e69 100644
--- a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriAnalyzerProvider.java
+++ b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriAnalyzerProvider.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.index.analysis;
 
-import java.util.List;
-import java.util.Set;
 import org.apache.lucene.analysis.ko.KoreanAnalyzer;
 import org.apache.lucene.analysis.ko.KoreanPartOfSpeechStopFilter;
 import org.apache.lucene.analysis.ko.KoreanTokenizer;
-import org.apache.lucene.analysis.ko.dict.UserDictionary;
 import org.apache.lucene.analysis.ko.POS;
+import org.apache.lucene.analysis.ko.dict.UserDictionary;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+import java.util.List;
+import java.util.Set;
+
 import static org.opensearch.index.analysis.NoriPartOfSpeechStopFilterFactory.resolvePOSList;
 
 public class NoriAnalyzerProvider extends AbstractIndexAnalyzerProvider<KoreanAnalyzer> {
@@ -52,7 +53,7 @@ public NoriAnalyzerProvider(IndexSettings indexSettings, Environment env, String
         super(indexSettings, name, settings);
         final KoreanTokenizer.DecompoundMode mode = NoriTokenizerFactory.getMode(settings);
         final UserDictionary userDictionary = NoriTokenizerFactory.getUserDictionary(env, settings);
-        final List<String> tagList = Analysis.getWordList(env, settings, "stoptags");
+        final List<String> tagList = Analysis.parseWordList(env, settings, "stoptags", s -> s);
         final Set<POS.Tag> stopTags = tagList != null ? resolvePOSList(tagList) : KoreanPartOfSpeechStopFilter.DEFAULT_STOP_TAGS;
         analyzer = new KoreanAnalyzer(userDictionary, mode, stopTags, false);
     }
diff --git a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriPartOfSpeechStopFilterFactory.java b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriPartOfSpeechStopFilterFactory.java
index 18cbc3c7c153d..5023db50422fc 100644
--- a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriPartOfSpeechStopFilterFactory.java
+++ b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriPartOfSpeechStopFilterFactory.java
@@ -48,7 +48,7 @@ public class NoriPartOfSpeechStopFilterFactory extends AbstractTokenFilterFactor
 
     public NoriPartOfSpeechStopFilterFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) {
         super(indexSettings, name, settings);
-        List<String> tagList = Analysis.getWordList(env, settings, "stoptags");
+        List<String> tagList = Analysis.parseWordList(env, settings, "stoptags", s -> s);
         this.stopTags = tagList != null ? resolvePOSList(tagList) : KoreanPartOfSpeechStopFilter.DEFAULT_STOP_TAGS;
     }
 
diff --git a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriTokenizerFactory.java b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriTokenizerFactory.java
index 5136277611e3a..9f3183194cdae 100644
--- a/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriTokenizerFactory.java
+++ b/plugins/analysis-nori/src/main/java/org/opensearch/index/analysis/NoriTokenizerFactory.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.index.analysis;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ko.KoreanTokenizer;
 import org.apache.lucene.analysis.ko.dict.UserDictionary;
@@ -47,6 +49,7 @@
 import java.util.Locale;
 
 public class NoriTokenizerFactory extends AbstractTokenizerFactory {
+    private static final Logger LOGGER = LogManager.getLogger(NoriTokenizerFactory.class);
     private static final String USER_DICT_PATH_OPTION = "user_dictionary";
     private static final String USER_DICT_RULES_OPTION = "user_dictionary_rules";
 
@@ -67,7 +70,7 @@ public static UserDictionary getUserDictionary(Environment env, Settings setting
                 "It is not allowed to use [" + USER_DICT_PATH_OPTION + "] in conjunction" + " with [" + USER_DICT_RULES_OPTION + "]"
             );
         }
-        List<String> ruleList = Analysis.getWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION, true);
+        List<String> ruleList = Analysis.parseWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION, s -> s);
         StringBuilder sb = new StringBuilder();
         if (ruleList == null || ruleList.isEmpty()) {
             return null;
@@ -78,7 +81,8 @@ public static UserDictionary getUserDictionary(Environment env, Settings setting
         try (Reader rulesReader = new StringReader(sb.toString())) {
             return UserDictionary.open(rulesReader);
         } catch (IOException e) {
-            throw new OpenSearchException("failed to load nori user dictionary", e);
+            LOGGER.error("Failed to load nori user dictionary", e);
+            throw new OpenSearchException("Failed to load nori user dictionary");
         }
     }
 
diff --git a/plugins/analysis-phonetic/licenses/commons-codec-1.13.jar.sha1 b/plugins/analysis-phonetic/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/analysis-phonetic/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/analysis-phonetic/licenses/commons-codec-1.15.jar.sha1 b/plugins/analysis-phonetic/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/analysis-phonetic/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index e2006546433fd..0000000000000
--- a/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-6f0f5c71052beee26e4ce99e1147ce406234f417
\ No newline at end of file
diff --git a/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.7.0.jar.sha1 b/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..c7b4d2dc6da75
--- /dev/null
+++ b/plugins/analysis-phonetic/licenses/lucene-analysis-phonetic-9.7.0.jar.sha1
@@ -0,0 +1 @@
+b7d47d54683b0b1e09b271c32d1b7d3eb1990f49
\ No newline at end of file
diff --git a/plugins/analysis-phonetic/src/main/java/org/opensearch/index/analysis/phonetic/KoelnerPhonetik.java b/plugins/analysis-phonetic/src/main/java/org/opensearch/index/analysis/phonetic/KoelnerPhonetik.java
index 01056b0983936..33e386af9f364 100644
--- a/plugins/analysis-phonetic/src/main/java/org/opensearch/index/analysis/phonetic/KoelnerPhonetik.java
+++ b/plugins/analysis-phonetic/src/main/java/org/opensearch/index/analysis/phonetic/KoelnerPhonetik.java
@@ -32,6 +32,9 @@
 
 package org.opensearch.index.analysis.phonetic;
 
+import org.apache.commons.codec.EncoderException;
+import org.apache.commons.codec.StringEncoder;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -41,9 +44,6 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import org.apache.commons.codec.EncoderException;
-import org.apache.commons.codec.StringEncoder;
-
 /**
  * K&ouml;lner Phonetik
  *
diff --git a/plugins/analysis-phonetic/src/test/java/org/opensearch/index/analysis/SimplePhoneticAnalysisTests.java b/plugins/analysis-phonetic/src/test/java/org/opensearch/index/analysis/SimplePhoneticAnalysisTests.java
index 69d9fe9762c32..d14aeae41bd63 100644
--- a/plugins/analysis-phonetic/src/test/java/org/opensearch/index/analysis/SimplePhoneticAnalysisTests.java
+++ b/plugins/analysis-phonetic/src/test/java/org/opensearch/index/analysis/SimplePhoneticAnalysisTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.index.analysis;
 
-import org.apache.lucene.tests.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.phonetic.DaitchMokotoffSoundexFilter;
+import org.apache.lucene.tests.analysis.BaseTokenStreamTestCase;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.AnalysisPhoneticPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.MatcherAssert;
diff --git a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/10_metaphone.yml b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/10_metaphone.yml
index 1be0d8525a1c6..2268d30c986df 100644
--- a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/10_metaphone.yml
+++ b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/10_metaphone.yml
@@ -31,4 +31,3 @@
     - match:  { tokens.1.token: joe  }
     - match:  { tokens.2.token: BLKS  }
     - match:  { tokens.3.token: bloggs  }
-
diff --git a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/20_double_metaphone.yml b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/20_double_metaphone.yml
index 84b0129414c8e..40215cc469fc9 100644
--- a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/20_double_metaphone.yml
+++ b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/20_double_metaphone.yml
@@ -28,4 +28,3 @@
 
     - length: { tokens: 1 }
     - match:  { tokens.0.token: SPRKLF }
-
diff --git a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/30_beider_morse.yml b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/30_beider_morse.yml
index bdd1ddef388df..dcc46484780dc 100644
--- a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/30_beider_morse.yml
+++ b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/30_beider_morse.yml
@@ -30,4 +30,3 @@
 
     - length: { tokens: 1 }
     - match:  { tokens.0.token: Svarts }
-
diff --git a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/50_daitch_mokotoff.yml b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/50_daitch_mokotoff.yml
index bee4c8bf5f432..9b173a710ea43 100644
--- a/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/50_daitch_mokotoff.yml
+++ b/plugins/analysis-phonetic/src/yamlRestTest/resources/rest-api-spec/test/analysis_phonetic/50_daitch_mokotoff.yml
@@ -27,4 +27,3 @@
 
     - length: { tokens: 1 }
     - match:  { tokens.0.token: "645740" }
-
diff --git a/plugins/analysis-smartcn/build.gradle b/plugins/analysis-smartcn/build.gradle
index 92f2774854715..d74d314ab0673 100644
--- a/plugins/analysis-smartcn/build.gradle
+++ b/plugins/analysis-smartcn/build.gradle
@@ -47,4 +47,3 @@ restResources {
 tasks.named("dependencyLicenses").configure {
   mapping from: /lucene-.*/, to: 'lucene'
 }
-
diff --git a/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index e675c5774f5a4..0000000000000
--- a/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-32aad8b8491df3c9862e7fe75e98bccdb6a25bda
\ No newline at end of file
diff --git a/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.7.0.jar.sha1 b/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..8df7245044171
--- /dev/null
+++ b/plugins/analysis-smartcn/licenses/lucene-analysis-smartcn-9.7.0.jar.sha1
@@ -0,0 +1 @@
+5e68b9816e6cff8ee15f5b350cf2ffa54f9828b7
\ No newline at end of file
diff --git a/plugins/analysis-smartcn/src/main/java/org/opensearch/index/analysis/SmartChineseStopTokenFilterFactory.java b/plugins/analysis-smartcn/src/main/java/org/opensearch/index/analysis/SmartChineseStopTokenFilterFactory.java
index c7449ce87111d..6aa251ceb65e8 100644
--- a/plugins/analysis-smartcn/src/main/java/org/opensearch/index/analysis/SmartChineseStopTokenFilterFactory.java
+++ b/plugins/analysis-smartcn/src/main/java/org/opensearch/index/analysis/SmartChineseStopTokenFilterFactory.java
@@ -40,6 +40,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
+
 import java.util.Map;
 import java.util.Set;
 
diff --git a/plugins/analysis-smartcn/src/test/java/org/opensearch/index/analysis/SimpleSmartChineseAnalysisTests.java b/plugins/analysis-smartcn/src/test/java/org/opensearch/index/analysis/SimpleSmartChineseAnalysisTests.java
index 1c71490dd9294..1e99d5b624da6 100644
--- a/plugins/analysis-smartcn/src/test/java/org/opensearch/index/analysis/SimpleSmartChineseAnalysisTests.java
+++ b/plugins/analysis-smartcn/src/test/java/org/opensearch/index/analysis/SimpleSmartChineseAnalysisTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.analysis;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.smartcn.AnalysisSmartChinesePlugin;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.MatcherAssert;
diff --git a/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 053f5c97d65dc..0000000000000
--- a/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ef546cfaaf727d93c4e86ddc7f77b525af135623
\ No newline at end of file
diff --git a/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.7.0.jar.sha1 b/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..974e4202f5ffb
--- /dev/null
+++ b/plugins/analysis-stempel/licenses/lucene-analysis-stempel-9.7.0.jar.sha1
@@ -0,0 +1 @@
+d23b1f05b471e05d0d6068b3ece7c8c65672eae7
\ No newline at end of file
diff --git a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/AnalysisPolishFactoryTests.java b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/AnalysisPolishFactoryTests.java
index da6699fc1e95e..567f5644acbf8 100644
--- a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/AnalysisPolishFactoryTests.java
+++ b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/AnalysisPolishFactoryTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.index.analysis;
 
 import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.tests.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.tests.analysis.MockTokenizer;
-import org.apache.lucene.analysis.Tokenizer;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.UUIDs;
diff --git a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/PolishAnalysisTests.java b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/PolishAnalysisTests.java
index 56e48c4fb30b0..ee9b2a6520de2 100644
--- a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/PolishAnalysisTests.java
+++ b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/PolishAnalysisTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.pl.PolishAnalyzer;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.analysis.pl.PolishStemTokenFilterFactory;
 import org.opensearch.plugin.analysis.stempel.AnalysisStempelPlugin;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/SimplePolishTokenFilterTests.java b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/SimplePolishTokenFilterTests.java
index fb47a6a24c198..34906b6508856 100644
--- a/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/SimplePolishTokenFilterTests.java
+++ b/plugins/analysis-stempel/src/test/java/org/opensearch/index/analysis/SimplePolishTokenFilterTests.java
@@ -38,7 +38,7 @@
 import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.stempel.AnalysisStempelPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index e5a2a0b0b4ab3..0000000000000
--- a/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21c3511469f67019804e41a8d83ffc5c36de6479
\ No newline at end of file
diff --git a/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.7.0.jar.sha1 b/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..dce408a7d40ef
--- /dev/null
+++ b/plugins/analysis-ukrainian/licenses/lucene-analysis-morfologik-9.7.0.jar.sha1
@@ -0,0 +1 @@
+dfb4313f3c68d337310522840d7144c1605d084a
\ No newline at end of file
diff --git a/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/SimpleUkrainianAnalyzerTests.java b/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/SimpleUkrainianAnalyzerTests.java
index deb5cf275d7f6..1e9cde8569063 100644
--- a/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/SimpleUkrainianAnalyzerTests.java
+++ b/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/SimpleUkrainianAnalyzerTests.java
@@ -36,7 +36,7 @@
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.ukrainian.AnalysisUkrainianPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/UkrainianAnalysisTests.java b/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/UkrainianAnalysisTests.java
index d0aefdaa1d9ec..5c2528b4814bd 100644
--- a/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/UkrainianAnalysisTests.java
+++ b/plugins/analysis-ukrainian/src/test/java/org/opensearch/index/analysis/UkrainianAnalysisTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.uk.UkrainianMorfologikAnalyzer;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugin.analysis.ukrainian.AnalysisUkrainianPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.MatcherAssert;
diff --git a/plugins/crypto-kms/build.gradle b/plugins/crypto-kms/build.gradle
new file mode 100644
index 0000000000000..c4a8609b6df48
--- /dev/null
+++ b/plugins/crypto-kms/build.gradle
@@ -0,0 +1,74 @@
+import org.opensearch.gradle.info.BuildParams
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+apply plugin: 'opensearch.build'
+apply plugin: 'opensearch.publish'
+apply plugin: 'opensearch.yaml-rest-test'
+
+opensearchplugin {
+  description 'AWS KMS plugin to provide crypto keys'
+  classname 'org.opensearch.crypto.kms.CryptoKmsPlugin'
+}
+
+ext {
+  // Do not fail on `javadoc` warning (ANTLR generated code)
+  failOnJavadocWarning = false
+}
+
+dependencies {
+  api "software.amazon.awssdk:sdk-core:${versions.aws}"
+  api "software.amazon.awssdk:aws-core:${versions.aws}"
+  api "software.amazon.awssdk:utils:${versions.aws}"
+  api "software.amazon.awssdk:auth:${versions.aws}"
+  api "software.amazon.awssdk:kms:${versions.aws}"
+  api "software.amazon.awssdk:http-client-spi:${versions.aws}"
+  api "software.amazon.awssdk:apache-client:${versions.aws}"
+  api "software.amazon.awssdk:regions:${versions.aws}"
+  api "software.amazon.awssdk:profiles:${versions.aws}"
+  api "software.amazon.awssdk:endpoints-spi:${versions.aws}"
+  api "software.amazon.awssdk:annotations:${versions.aws}"
+  api "software.amazon.awssdk:metrics-spi:${versions.aws}"
+  api "software.amazon.awssdk:json-utils:${versions.aws}"
+  api "software.amazon.awssdk:protocol-core:${versions.aws}"
+  api "software.amazon.awssdk:aws-query-protocol:${versions.aws}"
+  api "software.amazon.awssdk:aws-json-protocol:${versions.aws}"
+  api "software.amazon.awssdk:third-party-jackson-core:${versions.aws}"
+  api "org.apache.httpcomponents:httpclient:${versions.httpclient}"
+  api "org.apache.httpcomponents:httpcore:${versions.httpcore}"
+  api "commons-logging:commons-logging:${versions.commonslogging}"
+  api "org.apache.logging.log4j:log4j-1.2-api:${versions.log4j}"
+  api "org.slf4j:slf4j-api:${versions.slf4j}"
+  api "commons-codec:commons-codec:${versions.commonscodec}"
+  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
+  api "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
+  api "org.reactivestreams:reactive-streams:${versions.reactivestreams}"
+}
+
+//testClusters.all {
+//  module ':modules:crypto'
+//}
+
+tasks.named("dependencyLicenses").configure {
+  mapping from: /jackson-.*/, to: 'jackson'
+  mapping from: /jaxb-.*/, to: 'jaxb'
+  mapping from: /netty-.*/, to: 'netty'
+}
+
+bundlePlugin {
+  from('config/crypto-kms') {
+    into 'config'
+  }
+}
+
+thirdPartyAudit.enabled = false
+testingConventions.enabled = false
diff --git a/plugins/crypto-kms/config/crypto-kms/log4j2.properties b/plugins/crypto-kms/config/crypto-kms/log4j2.properties
new file mode 100644
index 0000000000000..285ac4a1d1376
--- /dev/null
+++ b/plugins/crypto-kms/config/crypto-kms/log4j2.properties
@@ -0,0 +1,22 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+# Modifications Copyright OpenSearch Contributors. See
+# GitHub history for details.
+#
+
+logger.com_amazonaws.name = software.amazon.awssdk
+logger.com_amazonaws.level = warn
+
+logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.name = software.amazon.awssdk.jmx.SdkMBeanRegistrySupport
+logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.level = error
+
+logger.com_amazonaws_metrics_AwsSdkMetrics.name = software.amazon.awssdk.metrics.AwsSdkMetrics
+logger.com_amazonaws_metrics_AwsSdkMetrics.level = error
+
+logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.name = software.amazon.awssdk.auth.profile.internal.BasicProfileConfigFileLoader
+logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.level = error
diff --git a/plugins/crypto-kms/licenses/annotations-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/annotations-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5a626eeb5725b
--- /dev/null
+++ b/plugins/crypto-kms/licenses/annotations-2.20.55.jar.sha1
@@ -0,0 +1 @@
+330e9d0e5f2401fffba5afe30f3740f400e8308d
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/grpc-context-LICENSE.txt b/plugins/crypto-kms/licenses/annotations-LICENSE.txt
similarity index 100%
rename from plugins/repository-gcs/licenses/grpc-context-LICENSE.txt
rename to plugins/crypto-kms/licenses/annotations-LICENSE.txt
diff --git a/plugins/crypto-kms/licenses/annotations-NOTICE.txt b/plugins/crypto-kms/licenses/annotations-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/annotations-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/apache-client-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/apache-client-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..3ee96bb6e4076
--- /dev/null
+++ b/plugins/crypto-kms/licenses/apache-client-2.20.55.jar.sha1
@@ -0,0 +1 @@
+5c149885667d41a306769505cfa481cfddf6f113
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/apache-client-LICENSE.txt b/plugins/crypto-kms/licenses/apache-client-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/apache-client-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/apache-client-NOTICE.txt b/plugins/crypto-kms/licenses/apache-client-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/apache-client-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/auth-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/auth-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..010464bdf9fd1
--- /dev/null
+++ b/plugins/crypto-kms/licenses/auth-2.20.55.jar.sha1
@@ -0,0 +1 @@
+e21f00a8a2096d5044f3eff176944256e01a175e
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/auth-LICENSE.txt b/plugins/crypto-kms/licenses/auth-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/auth-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/auth-NOTICE.txt b/plugins/crypto-kms/licenses/auth-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/auth-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/aws-core-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/aws-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4b4ee1db864a8
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+734427c2cece98a8cb90871b78d2311e4a7ef746
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/aws-core-LICENSE.txt b/plugins/crypto-kms/licenses/aws-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/aws-core-NOTICE.txt b/plugins/crypto-kms/licenses/aws-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/aws-json-protocol-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/aws-json-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..45a88305c1928
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-json-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a52731c86b974aefa5bbb1c545f407811a0163b1
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/aws-json-protocol-LICENSE.txt b/plugins/crypto-kms/licenses/aws-json-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-json-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/aws-json-protocol-NOTICE.txt b/plugins/crypto-kms/licenses/aws-json-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-json-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/aws-query-protocol-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/aws-query-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..ba5f43378730c
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-query-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+ac116215cc85366f0bdffee53b4c21e7a7fe03ef
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/aws-query-protocol-LICENSE.txt b/plugins/crypto-kms/licenses/aws-query-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-query-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/aws-query-protocol-NOTICE.txt b/plugins/crypto-kms/licenses/aws-query-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/aws-query-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/commons-codec-1.15.jar.sha1 b/plugins/crypto-kms/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/commons-codec-LICENSE.txt b/plugins/crypto-kms/licenses/commons-codec-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-codec-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/commons-codec-NOTICE.txt b/plugins/crypto-kms/licenses/commons-codec-NOTICE.txt
new file mode 100644
index 0000000000000..56916449bbe10
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-codec-NOTICE.txt
@@ -0,0 +1,17 @@
+Apache Commons Codec
+Copyright 2002-2015 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+
+src/test/org/apache/commons/codec/language/DoubleMetaphoneTest.java
+contains test data from http://aspell.net/test/orig/batch0.tab.
+Copyright (C) 2002 Kevin Atkinson (kevina@gnu.org)
+
+===============================================================================
+
+The content of package org.apache.commons.codec.language.bm has been translated
+from the original php source code available at http://stevemorse.org/phoneticinfo.htm
+with permission from the original authors.
+Original source copyright:
+Copyright (c) 2008 Alexander Beider & Stephen P. Morse.
diff --git a/plugins/crypto-kms/licenses/commons-logging-1.2.jar.sha1 b/plugins/crypto-kms/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/commons-logging-LICENSE.txt b/plugins/crypto-kms/licenses/commons-logging-LICENSE.txt
new file mode 100644
index 0000000000000..57bc88a15a0ee
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-logging-LICENSE.txt
@@ -0,0 +1,202 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
diff --git a/plugins/crypto-kms/licenses/commons-logging-NOTICE.txt b/plugins/crypto-kms/licenses/commons-logging-NOTICE.txt
new file mode 100644
index 0000000000000..72eb32a902458
--- /dev/null
+++ b/plugins/crypto-kms/licenses/commons-logging-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache Commons CLI
+Copyright 2001-2009 The Apache Software Foundation
+
+This product includes software developed by
+The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/crypto-kms/licenses/endpoints-spi-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/endpoints-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5bc0e31166c77
--- /dev/null
+++ b/plugins/crypto-kms/licenses/endpoints-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+085f82038ee86a7d6cd568fe7edd842978d92de3
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/endpoints-spi-LICENSE.txt b/plugins/crypto-kms/licenses/endpoints-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/endpoints-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/endpoints-spi-NOTICE.txt b/plugins/crypto-kms/licenses/endpoints-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/endpoints-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/http-client-spi-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/http-client-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..523cf43dcb2e9
--- /dev/null
+++ b/plugins/crypto-kms/licenses/http-client-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+34f9b10c1a46038a0ceebdd750ba3a413a862ceb
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/http-client-spi-LICENSE.txt b/plugins/crypto-kms/licenses/http-client-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/http-client-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/http-client-spi-NOTICE.txt b/plugins/crypto-kms/licenses/http-client-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/http-client-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/httpclient-4.5.14.jar.sha1 b/plugins/crypto-kms/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/httpclient-LICENSE.txt b/plugins/crypto-kms/licenses/httpclient-LICENSE.txt
new file mode 100644
index 0000000000000..32f01eda18fe9
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpclient-LICENSE.txt
@@ -0,0 +1,558 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+=========================================================================
+
+This project includes Public Suffix List copied from
+<https://publicsuffix.org/list/effective_tld_names.dat>
+licensed under the terms of the Mozilla Public License, v. 2.0
+
+Full license text: <http://mozilla.org/MPL/2.0/>
+
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.
diff --git a/plugins/crypto-kms/licenses/httpclient-NOTICE.txt b/plugins/crypto-kms/licenses/httpclient-NOTICE.txt
new file mode 100644
index 0000000000000..4f6058178b201
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpclient-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache HttpComponents Client
+Copyright 1999-2015 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/crypto-kms/licenses/httpcore-4.4.16.jar.sha1 b/plugins/crypto-kms/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/httpcore-LICENSE.txt b/plugins/crypto-kms/licenses/httpcore-LICENSE.txt
new file mode 100644
index 0000000000000..72819a9f06f2a
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpcore-LICENSE.txt
@@ -0,0 +1,241 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+=========================================================================
+
+This project contains annotations in the package org.apache.http.annotation
+which are derived from JCIP-ANNOTATIONS
+Copyright (c) 2005 Brian Goetz and Tim Peierls.
+See http://www.jcip.net and the Creative Commons Attribution License
+(http://creativecommons.org/licenses/by/2.5)
+Full text: http://creativecommons.org/licenses/by/2.5/legalcode
+
+License
+
+THE WORK (AS DEFINED BELOW) IS PROVIDED UNDER THE TERMS OF THIS CREATIVE COMMONS PUBLIC LICENSE ("CCPL" OR "LICENSE"). THE WORK IS PROTECTED BY COPYRIGHT AND/OR OTHER APPLICABLE LAW. ANY USE OF THE WORK OTHER THAN AS AUTHORIZED UNDER THIS LICENSE OR COPYRIGHT LAW IS PROHIBITED.
+
+BY EXERCISING ANY RIGHTS TO THE WORK PROVIDED HERE, YOU ACCEPT AND AGREE TO BE BOUND BY THE TERMS OF THIS LICENSE. THE LICENSOR GRANTS YOU THE RIGHTS CONTAINED HERE IN CONSIDERATION OF YOUR ACCEPTANCE OF SUCH TERMS AND CONDITIONS.
+
+1. Definitions
+
+    "Collective Work" means a work, such as a periodical issue, anthology or encyclopedia, in which the Work in its entirety in unmodified form, along with a number of other contributions, constituting separate and independent works in themselves, are assembled into a collective whole. A work that constitutes a Collective Work will not be considered a Derivative Work (as defined below) for the purposes of this License.
+    "Derivative Work" means a work based upon the Work or upon the Work and other pre-existing works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which the Work may be recast, transformed, or adapted, except that a work that constitutes a Collective Work will not be considered a Derivative Work for the purpose of this License. For the avoidance of doubt, where the Work is a musical composition or sound recording, the synchronization of the Work in timed-relation with a moving image ("synching") will be considered a Derivative Work for the purpose of this License.
+    "Licensor" means the individual or entity that offers the Work under the terms of this License.
+    "Original Author" means the individual or entity who created the Work.
+    "Work" means the copyrightable work of authorship offered under the terms of this License.
+    "You" means an individual or entity exercising rights under this License who has not previously violated the terms of this License with respect to the Work, or who has received express permission from the Licensor to exercise rights under this License despite a previous violation.
+
+2. Fair Use Rights. Nothing in this license is intended to reduce, limit, or restrict any rights arising from fair use, first sale or other limitations on the exclusive rights of the copyright owner under copyright law or other applicable laws.
+
+3. License Grant. Subject to the terms and conditions of this License, Licensor hereby grants You a worldwide, royalty-free, non-exclusive, perpetual (for the duration of the applicable copyright) license to exercise the rights in the Work as stated below:
+
+    to reproduce the Work, to incorporate the Work into one or more Collective Works, and to reproduce the Work as incorporated in the Collective Works;
+    to create and reproduce Derivative Works;
+    to distribute copies or phonorecords of, display publicly, perform publicly, and perform publicly by means of a digital audio transmission the Work including as incorporated in Collective Works;
+    to distribute copies or phonorecords of, display publicly, perform publicly, and perform publicly by means of a digital audio transmission Derivative Works.
+
+    For the avoidance of doubt, where the work is a musical composition:
+        Performance Royalties Under Blanket Licenses. Licensor waives the exclusive right to collect, whether individually or via a performance rights society (e.g. ASCAP, BMI, SESAC), royalties for the public performance or public digital performance (e.g. webcast) of the Work.
+        Mechanical Rights and Statutory Royalties. Licensor waives the exclusive right to collect, whether individually or via a music rights agency or designated agent (e.g. Harry Fox Agency), royalties for any phonorecord You create from the Work ("cover version") and distribute, subject to the compulsory license created by 17 USC Section 115 of the US Copyright Act (or the equivalent in other jurisdictions).
+    Webcasting Rights and Statutory Royalties. For the avoidance of doubt, where the Work is a sound recording, Licensor waives the exclusive right to collect, whether individually or via a performance-rights society (e.g. SoundExchange), royalties for the public digital performance (e.g. webcast) of the Work, subject to the compulsory license created by 17 USC Section 114 of the US Copyright Act (or the equivalent in other jurisdictions).
+
+The above rights may be exercised in all media and formats whether now known or hereafter devised. The above rights include the right to make such modifications as are technically necessary to exercise the rights in other media and formats. All rights not expressly granted by Licensor are hereby reserved.
+
+4. Restrictions.The license granted in Section 3 above is expressly made subject to and limited by the following restrictions:
+
+    You may distribute, publicly display, publicly perform, or publicly digitally perform the Work only under the terms of this License, and You must include a copy of, or the Uniform Resource Identifier for, this License with every copy or phonorecord of the Work You distribute, publicly display, publicly perform, or publicly digitally perform. You may not offer or impose any terms on the Work that alter or restrict the terms of this License or the recipients' exercise of the rights granted hereunder. You may not sublicense the Work. You must keep intact all notices that refer to this License and to the disclaimer of warranties. You may not distribute, publicly display, publicly perform, or publicly digitally perform the Work with any technological measures that control access or use of the Work in a manner inconsistent with the terms of this License Agreement. The above applies to the Work as incorporated in a Collective Work, but this does not require the Collective Work apart from the Work itself to be made subject to the terms of this License. If You create a Collective Work, upon notice from any Licensor You must, to the extent practicable, remove from the Collective Work any credit as required by clause 4(b), as requested. If You create a Derivative Work, upon notice from any Licensor You must, to the extent practicable, remove from the Derivative Work any credit as required by clause 4(b), as requested.
+    If you distribute, publicly display, publicly perform, or publicly digitally perform the Work or any Derivative Works or Collective Works, You must keep intact all copyright notices for the Work and provide, reasonable to the medium or means You are utilizing: (i) the name of the Original Author (or pseudonym, if applicable) if supplied, and/or (ii) if the Original Author and/or Licensor designate another party or parties (e.g. a sponsor institute, publishing entity, journal) for attribution in Licensor's copyright notice, terms of service or by other reasonable means, the name of such party or parties; the title of the Work if supplied; to the extent reasonably practicable, the Uniform Resource Identifier, if any, that Licensor specifies to be associated with the Work, unless such URI does not refer to the copyright notice or licensing information for the Work; and in the case of a Derivative Work, a credit identifying the use of the Work in the Derivative Work (e.g., "French translation of the Work by Original Author," or "Screenplay based on original Work by Original Author"). Such credit may be implemented in any reasonable manner; provided, however, that in the case of a Derivative Work or Collective Work, at a minimum such credit will appear where any other comparable authorship credit appears and in a manner at least as prominent as such other comparable authorship credit.
+
+5. Representations, Warranties and Disclaimer
+
+UNLESS OTHERWISE MUTUALLY AGREED TO BY THE PARTIES IN WRITING, LICENSOR OFFERS THE WORK AS-IS AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND CONCERNING THE WORK, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTIBILITY, FITNESS FOR A PARTICULAR PURPOSE, NONINFRINGEMENT, OR THE ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OF ABSENCE OF ERRORS, WHETHER OR NOT DISCOVERABLE. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO SUCH EXCLUSION MAY NOT APPLY TO YOU.
+
+6. Limitation on Liability. EXCEPT TO THE EXTENT REQUIRED BY APPLICABLE LAW, IN NO EVENT WILL LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY FOR ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES ARISING OUT OF THIS LICENSE OR THE USE OF THE WORK, EVEN IF LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+
+7. Termination
+
+    This License and the rights granted hereunder will terminate automatically upon any breach by You of the terms of this License. Individuals or entities who have received Derivative Works or Collective Works from You under this License, however, will not have their licenses terminated provided such individuals or entities remain in full compliance with those licenses. Sections 1, 2, 5, 6, 7, and 8 will survive any termination of this License.
+    Subject to the above terms and conditions, the license granted here is perpetual (for the duration of the applicable copyright in the Work). Notwithstanding the above, Licensor reserves the right to release the Work under different license terms or to stop distributing the Work at any time; provided, however that any such election will not serve to withdraw this License (or any other license that has been, or is required to be, granted under the terms of this License), and this License will continue in full force and effect unless terminated as stated above.
+
+8. Miscellaneous
+
+    Each time You distribute or publicly digitally perform the Work or a Collective Work, the Licensor offers to the recipient a license to the Work on the same terms and conditions as the license granted to You under this License.
+    Each time You distribute or publicly digitally perform a Derivative Work, Licensor offers to the recipient a license to the original Work on the same terms and conditions as the license granted to You under this License.
+    If any provision of this License is invalid or unenforceable under applicable law, it shall not affect the validity or enforceability of the remainder of the terms of this License, and without further action by the parties to this agreement, such provision shall be reformed to the minimum extent necessary to make such provision valid and enforceable.
+    No term or provision of this License shall be deemed waived and no breach consented to unless such waiver or consent shall be in writing and signed by the party to be charged with such waiver or consent.
+    This License constitutes the entire agreement between the parties with respect to the Work licensed here. There are no understandings, agreements or representations with respect to the Work not specified here. Licensor shall not be bound by any additional provisions that may appear in any communication from You. This License may not be modified without the mutual written agreement of the Licensor and You.
diff --git a/plugins/crypto-kms/licenses/httpcore-NOTICE.txt b/plugins/crypto-kms/licenses/httpcore-NOTICE.txt
new file mode 100644
index 0000000000000..c0be50a505ec1
--- /dev/null
+++ b/plugins/crypto-kms/licenses/httpcore-NOTICE.txt
@@ -0,0 +1,8 @@
+Apache HttpComponents Core
+Copyright 2005-2014 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+
+This project contains annotations derived from JCIP-ANNOTATIONS
+Copyright (c) 2005 Brian Goetz and Tim Peierls. See http://www.jcip.net
diff --git a/plugins/repository-hdfs/licenses/jackson-databind-LICENSE.txt b/plugins/crypto-kms/licenses/jackson-LICENSE
similarity index 100%
rename from plugins/repository-hdfs/licenses/jackson-databind-LICENSE.txt
rename to plugins/crypto-kms/licenses/jackson-LICENSE
diff --git a/plugins/repository-hdfs/licenses/jackson-databind-NOTICE.txt b/plugins/crypto-kms/licenses/jackson-NOTICE
similarity index 100%
rename from plugins/repository-hdfs/licenses/jackson-databind-NOTICE.txt
rename to plugins/crypto-kms/licenses/jackson-NOTICE
diff --git a/plugins/crypto-kms/licenses/jackson-annotations-2.15.2.jar.sha1 b/plugins/crypto-kms/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/plugins/crypto-kms/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/jackson-databind-2.15.2.jar.sha1 b/plugins/crypto-kms/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/plugins/crypto-kms/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/json-utils-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/json-utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..a19b00e62f8b5
--- /dev/null
+++ b/plugins/crypto-kms/licenses/json-utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+cd6710900e3190eac4c4496ae529ce08680dd320
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/json-utils-LICENSE.txt b/plugins/crypto-kms/licenses/json-utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/json-utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/json-utils-NOTICE.txt b/plugins/crypto-kms/licenses/json-utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/json-utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/kms-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/kms-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..0b4e98f59a066
--- /dev/null
+++ b/plugins/crypto-kms/licenses/kms-2.20.55.jar.sha1
@@ -0,0 +1 @@
+389780132dd417ab58e0bb9b269d738ff839605f
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/kms-LICENSE.txt b/plugins/crypto-kms/licenses/kms-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/kms-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/kms-NOTICE.txt b/plugins/crypto-kms/licenses/kms-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/kms-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/crypto-kms/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/crypto-kms/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/log4j-LICENSE.txt b/plugins/crypto-kms/licenses/log4j-LICENSE.txt
new file mode 100644
index 0000000000000..6279e5206de13
--- /dev/null
+++ b/plugins/crypto-kms/licenses/log4j-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 1999-2005 The Apache Software Foundation
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/log4j-NOTICE.txt b/plugins/crypto-kms/licenses/log4j-NOTICE.txt
new file mode 100644
index 0000000000000..0375732360047
--- /dev/null
+++ b/plugins/crypto-kms/licenses/log4j-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache log4j
+Copyright 2007 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/metrics-spi-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/metrics-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..db6701d87892a
--- /dev/null
+++ b/plugins/crypto-kms/licenses/metrics-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8a0eae705b27465516f3b09cc9918e40963d534d
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/metrics-spi-LICENSE.txt b/plugins/crypto-kms/licenses/metrics-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/metrics-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/metrics-spi-NOTICE.txt b/plugins/crypto-kms/licenses/metrics-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/metrics-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/profiles-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/profiles-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..b7104cf0939e6
--- /dev/null
+++ b/plugins/crypto-kms/licenses/profiles-2.20.55.jar.sha1
@@ -0,0 +1 @@
+959aad08b2f24057bf286c761b49e3af31a0a623
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/profiles-LICENSE.txt b/plugins/crypto-kms/licenses/profiles-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/profiles-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/profiles-NOTICE.txt b/plugins/crypto-kms/licenses/profiles-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/profiles-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/protocol-core-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/protocol-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4dee45f4d9dd3
--- /dev/null
+++ b/plugins/crypto-kms/licenses/protocol-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+0935e3ab32962a890f1d13bf39ba2167d9d692f9
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/protocol-core-LICENSE.txt b/plugins/crypto-kms/licenses/protocol-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/protocol-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/protocol-core-NOTICE.txt b/plugins/crypto-kms/licenses/protocol-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/protocol-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/reactive-streams-1.0.4.jar.sha1 b/plugins/crypto-kms/licenses/reactive-streams-1.0.4.jar.sha1
new file mode 100644
index 0000000000000..45a80e3f7e361
--- /dev/null
+++ b/plugins/crypto-kms/licenses/reactive-streams-1.0.4.jar.sha1
@@ -0,0 +1 @@
+3864a1320d97d7b045f729a326e1e077661f31b7
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/reactive-streams-LICENSE.txt b/plugins/crypto-kms/licenses/reactive-streams-LICENSE.txt
new file mode 100644
index 0000000000000..1e3c7e7c77495
--- /dev/null
+++ b/plugins/crypto-kms/licenses/reactive-streams-LICENSE.txt
@@ -0,0 +1,21 @@
+MIT No Attribution
+
+Copyright 2014 Reactive Streams
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15on-NOTICE.txt b/plugins/crypto-kms/licenses/reactive-streams-NOTICE.txt
similarity index 100%
rename from plugins/ingest-attachment/licenses/bcpkix-jdk15on-NOTICE.txt
rename to plugins/crypto-kms/licenses/reactive-streams-NOTICE.txt
diff --git a/plugins/crypto-kms/licenses/regions-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/regions-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..993fc2f97de62
--- /dev/null
+++ b/plugins/crypto-kms/licenses/regions-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a117c19b4a30e902f4f1cc4bef6b5c10cc9aef31
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/regions-LICENSE.txt b/plugins/crypto-kms/licenses/regions-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/regions-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/regions-NOTICE.txt b/plugins/crypto-kms/licenses/regions-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/regions-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/sdk-core-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/sdk-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5f12be9c08c5b
--- /dev/null
+++ b/plugins/crypto-kms/licenses/sdk-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8f2347feaf2575560ca89a2caa8d0243dbeb17a9
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/sdk-core-LICENSE.txt b/plugins/crypto-kms/licenses/sdk-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/sdk-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/sdk-core-NOTICE.txt b/plugins/crypto-kms/licenses/sdk-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/sdk-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/crypto-kms/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/crypto-kms/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/slf4j-api-LICENSE.txt b/plugins/crypto-kms/licenses/slf4j-api-LICENSE.txt
new file mode 100644
index 0000000000000..2be7689435062
--- /dev/null
+++ b/plugins/crypto-kms/licenses/slf4j-api-LICENSE.txt
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2022 QOS.ch
+All rights reserved.
+
+Permission is hereby granted, free  of charge, to any person obtaining
+a  copy  of this  software  and  associated  documentation files  (the
+"Software"), to  deal in  the Software without  restriction, including
+without limitation  the rights to  use, copy, modify,  merge, publish,
+distribute,  sublicense, and/or sell  copies of  the Software,  and to
+permit persons to whom the Software  is furnished to do so, subject to
+the following conditions:
+
+The  above  copyright  notice  and  this permission  notice  shall  be
+included in all copies or substantial portions of the Software.
+
+THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
+EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
+MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15on-NOTICE.txt b/plugins/crypto-kms/licenses/slf4j-api-NOTICE.txt
similarity index 100%
rename from plugins/ingest-attachment/licenses/bcprov-jdk15on-NOTICE.txt
rename to plugins/crypto-kms/licenses/slf4j-api-NOTICE.txt
diff --git a/plugins/crypto-kms/licenses/third-party-jackson-core-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/third-party-jackson-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..e7eebbb98f1fe
--- /dev/null
+++ b/plugins/crypto-kms/licenses/third-party-jackson-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+956912f26056fc7d46b2db566362fe5f7a8c0e14
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/third-party-jackson-core-LICENSE.txt b/plugins/crypto-kms/licenses/third-party-jackson-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/third-party-jackson-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/third-party-jackson-core-NOTICE.txt b/plugins/crypto-kms/licenses/third-party-jackson-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/third-party-jackson-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/licenses/utils-2.20.55.jar.sha1 b/plugins/crypto-kms/licenses/utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..fc4cde604e33c
--- /dev/null
+++ b/plugins/crypto-kms/licenses/utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+d3e1bbbc19795eadbeb4dd963a94647576644097
\ No newline at end of file
diff --git a/plugins/crypto-kms/licenses/utils-LICENSE.txt b/plugins/crypto-kms/licenses/utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/crypto-kms/licenses/utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/crypto-kms/licenses/utils-NOTICE.txt b/plugins/crypto-kms/licenses/utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/crypto-kms/licenses/utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/AmazonKmsClientReference.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/AmazonKmsClientReference.java
new file mode 100644
index 0000000000000..8cd07f681f9cd
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/AmazonKmsClientReference.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.services.kms.KmsClient;
+
+import org.opensearch.common.concurrent.RefCountedReleasable;
+
+/**
+ * Handles the shutdown of the wrapped {@link KmsClient} using reference
+ * counting.
+ */
+public class AmazonKmsClientReference extends RefCountedReleasable<KmsClient> {
+
+    AmazonKmsClientReference(KmsClient client) {
+        super("AWS_KMS_CLIENT", client, client::close);
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CredentialProviderFactory.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CredentialProviderFactory.java
new file mode 100644
index 0000000000000..87a10f1408b8d
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CredentialProviderFactory.java
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.ContainerCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.InstanceProfileCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.SdkSystemSetting;
+
+import java.util.function.Supplier;
+
+/**
+ * Creates credential providers based on the provided configuration.
+ */
+public class CredentialProviderFactory {
+
+    /**
+     * Credential provider for EC2/ECS container
+     */
+    static class PrivilegedInstanceProfileCredentialsProvider implements AwsCredentialsProvider {
+        private final AwsCredentialsProvider credentials;
+
+        private PrivilegedInstanceProfileCredentialsProvider() {
+            this.credentials = initializeProvider();
+        }
+
+        private AwsCredentialsProvider initializeProvider() {
+            if (SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI.getStringValue().isPresent()
+                || SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_FULL_URI.getStringValue().isPresent()) {
+
+                return ContainerCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
+            }
+            // InstanceProfileCredentialsProvider as last item of chain
+            return InstanceProfileCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
+        }
+
+        @Override
+        public AwsCredentials resolveCredentials() {
+            return SocketAccess.doPrivileged(credentials::resolveCredentials);
+        }
+    }
+
+    /**
+     * Creates a credential provider based on the provided configuration.
+     * @param staticCredsSupplier Static credentials are used in case supplier returns a non-null instance.
+     * @return Credential provider instance.
+     */
+    public AwsCredentialsProvider createAwsCredentialsProvider(Supplier<AwsCredentials> staticCredsSupplier) {
+        AwsCredentials awsCredentials = staticCredsSupplier.get();
+        if (awsCredentials != null) {
+            return StaticCredentialsProvider.create(awsCredentials);
+        }
+
+        // Add other credential providers here
+        return new PrivilegedInstanceProfileCredentialsProvider();
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CryptoKmsPlugin.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CryptoKmsPlugin.java
new file mode 100644
index 0000000000000..f2ea9e37a0c09
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/CryptoKmsPlugin.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import org.opensearch.SpecialPermission;
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.crypto.MasterKeyProvider;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.CryptoKeyProviderPlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.ReloadablePlugin;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * AWS KMS based crypto key provider plugin.
+ */
+public class CryptoKmsPlugin extends Plugin implements CryptoKeyProviderPlugin, ReloadablePlugin {
+    private static final String PROVIDER_NAME = "aws-kms";
+
+    static {
+        SpecialPermission.check();
+    }
+
+    private final Settings settings;
+    // protected for testing
+    protected final KmsService kmsService;
+
+    public CryptoKmsPlugin(Settings settings) {
+        this(settings, new KmsService());
+    }
+
+    protected CryptoKmsPlugin(Settings settings, KmsService kmsService) {
+        this.settings = settings;
+        this.kmsService = kmsService;
+        // eagerly load client settings when secure settings are accessible
+        reload(settings);
+    }
+
+    @Override
+    public MasterKeyProvider createKeyProvider(CryptoMetadata cryptoMetadata) {
+        return kmsService.createMasterKeyProvider(cryptoMetadata);
+    }
+
+    @Override
+    public String type() {
+        return PROVIDER_NAME;
+    }
+
+    @Override
+    public List<Setting<?>> getSettings() {
+        return Arrays.asList(
+            KmsClientSettings.ACCESS_KEY_SETTING,
+            KmsClientSettings.SECRET_KEY_SETTING,
+            KmsClientSettings.SESSION_TOKEN_SETTING,
+            KmsClientSettings.ENDPOINT_SETTING,
+            KmsClientSettings.REGION_SETTING,
+            KmsClientSettings.PROXY_HOST_SETTING,
+            KmsClientSettings.PROXY_PORT_SETTING,
+            KmsClientSettings.PROXY_USERNAME_SETTING,
+            KmsClientSettings.PROXY_PASSWORD_SETTING,
+            KmsClientSettings.READ_TIMEOUT_SETTING,
+            KmsService.ENC_CTX_SETTING,
+            KmsService.KEY_ARN_SETTING
+        );
+    }
+
+    @Override
+    public void reload(Settings settings) {
+        // secure settings should be readable
+        final KmsClientSettings clientSettings = KmsClientSettings.getClientSettings(settings);
+        kmsService.refreshAndClearCache(clientSettings);
+    }
+
+    @Override
+    public void close() {
+        kmsService.close();
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsClientSettings.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsClientSettings.java
new file mode 100644
index 0000000000000..187a80a6355f7
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsClientSettings.java
@@ -0,0 +1,258 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.settings.SecureSetting;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsException;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.settings.SecureString;
+
+import java.util.Locale;
+import java.util.Objects;
+
+/**
+ * A container for settings used to create an kms client.
+ */
+public class KmsClientSettings {
+
+    /** The access key (ie login id) for connecting to kms. */
+    static final Setting<SecureString> ACCESS_KEY_SETTING = SecureSetting.secureString("kms.access_key", null);
+
+    /** The secret key (ie password) for connecting to kms. */
+    static final Setting<SecureString> SECRET_KEY_SETTING = SecureSetting.secureString("kms.secret_key", null);
+
+    /** The session token for connecting to kms. */
+    static final Setting<SecureString> SESSION_TOKEN_SETTING = SecureSetting.secureString("kms.session_token", null);
+
+    /** The host name of a proxy to connect to kms through. */
+    static final Setting<String> PROXY_HOST_SETTING = Setting.simpleString("kms.proxy.host", Property.NodeScope);
+
+    /** The port of a proxy to connect to kms through. */
+    static final Setting<Integer> PROXY_PORT_SETTING = Setting.intSetting("kms.proxy.port", 80, 0, 1 << 16, Property.NodeScope);
+
+    /** An override for the kms endpoint to connect to. */
+    static final Setting<String> ENDPOINT_SETTING = new Setting<>("kms.endpoint", "", s -> s.toLowerCase(Locale.ROOT), Property.NodeScope);
+
+    /** An override for the scoping region for authentication. */
+    static final Setting<String> REGION_SETTING = new Setting<>("kms.region", "", s -> s.toLowerCase(Locale.ROOT), Property.NodeScope);
+
+    /** The username of a proxy to connect to kms through. */
+    static final Setting<SecureString> PROXY_USERNAME_SETTING = SecureSetting.secureString("kms.proxy.username", null);
+
+    /** The password of a proxy to connect to kms through. */
+    static final Setting<SecureString> PROXY_PASSWORD_SETTING = SecureSetting.secureString("kms.proxy.password", null);
+
+    /** The socket timeout for connecting to kms. */
+    static final Setting<TimeValue> READ_TIMEOUT_SETTING = Setting.timeSetting(
+        "kms.read_timeout",
+        TimeValue.timeValueMillis(50_000),
+        Property.NodeScope
+    );
+
+    private static final Logger logger = LogManager.getLogger(KmsClientSettings.class);
+
+    /** Credentials to authenticate with kms. */
+    final AwsCredentials credentials;
+
+    /**
+     * The kms endpoint the client should talk to, or empty string to use the
+     * default.
+     */
+    final String endpoint;
+
+    /**
+     * The kms signing region.
+     */
+    final String region;
+
+    /** An optional proxy host that requests to kms should be made through. */
+    final String proxyHost;
+
+    /** The port number the proxy host should be connected on. */
+    final int proxyPort;
+
+    // these should be "secure" yet the api for the kms client only takes String, so
+    // storing them
+    // as SecureString here won't really help with anything
+    /** An optional username for the proxy host, for basic authentication. */
+    final String proxyUsername;
+
+    /** An optional password for the proxy host, for basic authentication. */
+    final String proxyPassword;
+
+    /** The read timeout for the kms client. */
+    final int readTimeoutMillis;
+
+    protected KmsClientSettings(
+        AwsCredentials credentials,
+        String endpoint,
+        String region,
+        String proxyHost,
+        int proxyPort,
+        String proxyUsername,
+        String proxyPassword,
+        int readTimeoutMillis
+    ) {
+        this.credentials = credentials;
+        this.endpoint = endpoint;
+        this.region = region;
+        this.proxyHost = proxyHost;
+        this.proxyPort = proxyPort;
+        this.proxyUsername = proxyUsername;
+        this.proxyPassword = proxyPassword;
+        this.readTimeoutMillis = readTimeoutMillis;
+    }
+
+    static AwsCredentials loadCredentials(Settings settings) {
+        try (
+            SecureString key = ACCESS_KEY_SETTING.get(settings);
+            SecureString secret = SECRET_KEY_SETTING.get(settings);
+            SecureString sessionToken = SESSION_TOKEN_SETTING.get(settings)
+        ) {
+            if (key.length() == 0 && secret.length() == 0) {
+                if (sessionToken.length() > 0) {
+                    throw new SettingsException(
+                        "Setting [{}] is set but [{}] and [{}] are not",
+                        SESSION_TOKEN_SETTING.getKey(),
+                        ACCESS_KEY_SETTING.getKey(),
+                        SECRET_KEY_SETTING.getKey()
+                    );
+                }
+
+                logger.debug("Using either environment variables, system properties or instance profile credentials");
+                return null;
+            } else {
+                if (key.length() == 0) {
+                    throw new SettingsException(
+                        "Setting [{}] is set but [{}] is not",
+                        SECRET_KEY_SETTING.getKey(),
+                        ACCESS_KEY_SETTING.getKey(),
+                        SECRET_KEY_SETTING.getKey()
+                    );
+                }
+                if (secret.length() == 0) {
+                    throw new SettingsException(
+                        "Setting [{}] is set but [{}] is not",
+                        ACCESS_KEY_SETTING.getKey(),
+                        SECRET_KEY_SETTING.getKey()
+                    );
+                }
+
+                final AwsCredentials credentials;
+                if (sessionToken.length() == 0) {
+                    logger.debug("Using basic key/secret credentials");
+                    credentials = AwsBasicCredentials.create(key.toString(), secret.toString());
+                } else {
+                    logger.debug("Using basic session credentials");
+                    credentials = AwsSessionCredentials.create(key.toString(), secret.toString(), sessionToken.toString());
+                }
+                return credentials;
+            }
+        }
+    }
+
+    /** Parse settings for a single client. */
+    static KmsClientSettings getClientSettings(Settings settings) {
+        final AwsCredentials credentials = loadCredentials(settings);
+        try (
+            SecureString proxyUsername = PROXY_USERNAME_SETTING.get(settings);
+            SecureString proxyPassword = PROXY_PASSWORD_SETTING.get(settings)
+        ) {
+            return new KmsClientSettings(
+                credentials,
+                ENDPOINT_SETTING.get(settings),
+                REGION_SETTING.get(settings),
+                PROXY_HOST_SETTING.get(settings),
+                PROXY_PORT_SETTING.get(settings),
+                proxyUsername.toString(),
+                proxyPassword.toString(),
+                (int) READ_TIMEOUT_SETTING.get(settings).millis()
+            );
+        }
+    }
+
+    KmsClientSettings getMetadataSettings(Settings settings) {
+        AwsCredentials newCredentials = loadCredentials(settings);
+        newCredentials = newCredentials == null ? this.credentials : newCredentials;
+        final Settings normalizedSettings = Settings.builder().put(settings).normalizePrefix("kms.").build();
+
+        String newProxyUsername = this.proxyUsername, newProxyPassword = this.proxyPassword;
+        if (PROXY_USERNAME_SETTING.exists(normalizedSettings)) {
+            try (SecureString proxyUsername = PROXY_USERNAME_SETTING.get(settings)) {
+                newProxyUsername = proxyUsername.toString();
+            }
+        }
+        if (PROXY_PASSWORD_SETTING.exists(normalizedSettings)) {
+            try (SecureString proxyPassword = PROXY_PASSWORD_SETTING.get(settings)) {
+                newProxyPassword = proxyPassword.toString();
+            }
+        }
+
+        String newEndpoint = getCryptoMetadataSettingOrExisting(ENDPOINT_SETTING, normalizedSettings, this.endpoint);
+        String newRegion = getCryptoMetadataSettingOrExisting(REGION_SETTING, normalizedSettings, this.region);
+        String newProxyHost = getCryptoMetadataSettingOrExisting(PROXY_HOST_SETTING, normalizedSettings, this.proxyHost);
+        int newProxyPort = getCryptoMetadataSettingOrExisting(PROXY_PORT_SETTING, normalizedSettings, this.proxyPort);
+        TimeValue newReadTimeout = getCryptoMetadataSettingOrExisting(
+            READ_TIMEOUT_SETTING,
+            normalizedSettings,
+            TimeValue.timeValueMillis(this.readTimeoutMillis)
+        );
+
+        return new KmsClientSettings(
+            newCredentials,
+            newEndpoint,
+            newRegion,
+            newProxyHost,
+            newProxyPort,
+            newProxyUsername,
+            newProxyPassword,
+            (int) newReadTimeout.millis()
+        );
+    }
+
+    private static <T> T getCryptoMetadataSettingOrExisting(Setting<T> setting, Settings normalizedSettings, T defaultValue) {
+        if (setting.exists(normalizedSettings)) {
+            return setting.get(normalizedSettings);
+        }
+        return defaultValue;
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        final KmsClientSettings that = (KmsClientSettings) o;
+        return readTimeoutMillis == that.readTimeoutMillis
+            && Objects.equals(credentials, that.credentials)
+            && Objects.equals(endpoint, that.endpoint)
+            && Objects.equals(region, that.region)
+            && Objects.equals(proxyHost, that.proxyHost)
+            && Objects.equals(proxyPort, that.proxyPort)
+            && Objects.equals(proxyUsername, that.proxyUsername)
+            && Objects.equals(proxyPassword, that.proxyPassword);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(readTimeoutMillis, credentials, endpoint, region, proxyHost, proxyPort, proxyUsername, proxyPassword);
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsMasterKeyProvider.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsMasterKeyProvider.java
new file mode 100644
index 0000000000000..9003e8bebd5ff
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsMasterKeyProvider.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.core.SdkBytes;
+import software.amazon.awssdk.services.kms.model.DataKeySpec;
+import software.amazon.awssdk.services.kms.model.DecryptRequest;
+import software.amazon.awssdk.services.kms.model.DecryptResponse;
+import software.amazon.awssdk.services.kms.model.GenerateDataKeyRequest;
+import software.amazon.awssdk.services.kms.model.GenerateDataKeyResponse;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.crypto.DataKeyPair;
+import org.opensearch.common.crypto.MasterKeyProvider;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+public class KmsMasterKeyProvider implements MasterKeyProvider {
+    private final Map<String, String> encryptionContext;
+    private final String keyArn;
+    private final Supplier<AmazonKmsClientReference> clientReferenceSupplier;
+
+    private static final Logger logger = LogManager.getLogger(KmsMasterKeyProvider.class);
+
+    public KmsMasterKeyProvider(
+        Map<String, String> encryptionContext,
+        String keyArn,
+        Supplier<AmazonKmsClientReference> clientReferenceSupplier
+    ) {
+        this.encryptionContext = encryptionContext;
+        this.keyArn = keyArn;
+        this.clientReferenceSupplier = clientReferenceSupplier;
+    }
+
+    @Override
+    public DataKeyPair generateDataPair() {
+        logger.info("Generating new data key pair");
+        try (AmazonKmsClientReference clientReference = clientReferenceSupplier.get()) {
+            GenerateDataKeyRequest request = GenerateDataKeyRequest.builder()
+                .encryptionContext(encryptionContext)
+                // Currently only 32 byte data key is supported. To add support for other key sizes add key providers
+                // in org.opensearch.encryption.CryptoManagerFactory.createCryptoProvider.
+                .keySpec(DataKeySpec.AES_256)
+                .keyId(keyArn)
+                .build();
+            GenerateDataKeyResponse dataKeyPair = SocketAccess.doPrivileged(() -> clientReference.get().generateDataKey(request));
+            return new DataKeyPair(dataKeyPair.plaintext().asByteArray(), dataKeyPair.ciphertextBlob().asByteArray());
+        }
+    }
+
+    @Override
+    public byte[] decryptKey(byte[] encryptedKey) {
+        try (AmazonKmsClientReference clientReference = clientReferenceSupplier.get()) {
+            DecryptRequest decryptRequest = DecryptRequest.builder().ciphertextBlob(SdkBytes.fromByteArray(encryptedKey)).build();
+            DecryptResponse decryptResponse = SocketAccess.doPrivileged(() -> clientReference.get().decrypt(decryptRequest));
+            return decryptResponse.plaintext().asByteArray();
+        }
+    }
+
+    @Override
+    public String getKeyId() {
+        return keyArn;
+    }
+
+    @Override
+    public Map<String, String> getEncryptionContext() {
+        return encryptionContext;
+    }
+
+    @Override
+    public void close() {}
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsService.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsService.java
new file mode 100644
index 0000000000000..108c88bd3bf80
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/KmsService.java
@@ -0,0 +1,272 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.http.apache.ApacheHttpClient;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.kms.KmsClient;
+import software.amazon.awssdk.services.kms.KmsClientBuilder;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.common.crypto.MasterKeyProvider;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+
+import java.io.Closeable;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.emptyMap;
+
+/**
+ * Service class which exposes APIs for communication with AWS KMS.
+ */
+public class KmsService implements Closeable {
+
+    private static final Logger logger = LogManager.getLogger(KmsService.class);
+    private final CredentialProviderFactory credentialProviderFactory;
+
+    static final Setting<String> ENC_CTX_SETTING = Setting.simpleString("kms.encryption_context", Setting.Property.NodeScope);
+
+    static final Setting<String> KEY_ARN_SETTING = Setting.simpleString("kms.key_arn", Setting.Property.NodeScope);
+
+    private volatile Map<KmsClientSettings, AmazonKmsClientReference> clientsCache = emptyMap();
+
+    /**
+     * Client settings calculated from static configuration and settings in the keystore.
+     */
+    private volatile KmsClientSettings staticClientSettings;
+
+    /**
+     * Client settings derived from those in {@link #staticClientSettings} by combining them with crypto settings
+     */
+    private volatile Map<Settings, KmsClientSettings> derivedClientSettings;
+
+    public KmsService() {
+        credentialProviderFactory = new CredentialProviderFactory();
+    }
+
+    private KmsClient buildClient(KmsClientSettings clientSettings) {
+        SocketAccess.doPrivilegedVoid(KmsService::setDefaultAwsProfilePath);
+        final AwsCredentialsProvider awsCredentialsProvider = buildCredentials(clientSettings);
+        final ClientOverrideConfiguration overrideConfiguration = buildOverrideConfiguration();
+        final ProxyConfiguration proxyConfiguration = SocketAccess.doPrivileged(() -> buildProxyConfiguration(clientSettings));
+        return buildClient(
+            awsCredentialsProvider,
+            proxyConfiguration,
+            overrideConfiguration,
+            clientSettings.endpoint,
+            clientSettings.region,
+            clientSettings.readTimeoutMillis
+        );
+    }
+
+    // proxy for testing
+    protected KmsClient buildClient(
+        AwsCredentialsProvider awsCredentialsProvider,
+        ProxyConfiguration proxyConfiguration,
+        ClientOverrideConfiguration overrideConfiguration,
+        String endpoint,
+        String region,
+        long readTimeoutMillis
+    ) {
+        ApacheHttpClient.Builder clientBuilder = ApacheHttpClient.builder()
+            .proxyConfiguration(proxyConfiguration)
+            .socketTimeout(Duration.ofMillis(readTimeoutMillis));
+
+        KmsClientBuilder builder = KmsClient.builder()
+            .region(Region.of(region))
+            .overrideConfiguration(overrideConfiguration)
+            .httpClientBuilder(clientBuilder)
+            .credentialsProvider(awsCredentialsProvider);
+
+        if (Strings.hasText(endpoint)) {
+            logger.debug("using explicit kms endpoint [{}]", endpoint);
+            builder.endpointOverride(URI.create(endpoint));
+        }
+
+        if (Strings.hasText(region)) {
+            logger.debug("using explicit kms region [{}]", region);
+            builder.region(Region.of(region));
+        }
+
+        return SocketAccess.doPrivileged(builder::build);
+    }
+
+    ProxyConfiguration buildProxyConfiguration(KmsClientSettings clientSettings) {
+        if (Strings.hasText(clientSettings.proxyHost)) {
+            try {
+                return ProxyConfiguration.builder()
+                    .endpoint(new URI("https", null, clientSettings.proxyHost, clientSettings.proxyPort, null, null, null))
+                    .username(clientSettings.proxyUsername)
+                    .password(clientSettings.proxyPassword)
+                    .build();
+            } catch (URISyntaxException e) {
+                throw SdkException.create("Invalid proxy URL", e);
+            }
+        } else {
+            return ProxyConfiguration.builder().build();
+        }
+    }
+
+    ClientOverrideConfiguration buildOverrideConfiguration() {
+        return ClientOverrideConfiguration.builder().retryPolicy(buildRetryPolicy()).build();
+    }
+
+    // pkg private for tests
+    RetryPolicy buildRetryPolicy() {
+        // Increase the number of retries in case of 5xx API responses.
+        // Note that AWS SDK v2 introduced a concept of TokenBucketRetryCondition, which effectively limits retries for
+        // APIs that have been failing continuously. It allocates tokens (default is 500), which means that once 500
+        // retries fail for any API on a bucket, new retries will only be allowed once some retries are rejected.
+        // https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/core/retry/conditions/TokenBucketRetryCondition.html
+        RetryPolicy.Builder retryPolicy = RetryPolicy.builder().numRetries(10);
+        return retryPolicy.build();
+    }
+
+    AwsCredentialsProvider buildCredentials(KmsClientSettings clientSettings) {
+        final AwsCredentials credentials = clientSettings.credentials;
+        return credentialProviderFactory.createAwsCredentialsProvider(() -> credentials);
+    }
+
+    public AmazonKmsClientReference client(CryptoMetadata cryptoMetadata) {
+        final KmsClientSettings clientSettings = settings(cryptoMetadata);
+        {
+            final AmazonKmsClientReference clientReference = clientsCache.get(clientSettings);
+            if (clientReference != null && clientReference.tryIncRef()) {
+                return clientReference;
+            }
+        }
+        synchronized (this) {
+            final AmazonKmsClientReference existing = clientsCache.get(clientSettings);
+            if (existing != null && existing.tryIncRef()) {
+                return existing;
+            }
+            final AmazonKmsClientReference clientReference = new AmazonKmsClientReference(
+                SocketAccess.doPrivileged(() -> buildClient(clientSettings))
+            );
+            clientReference.incRef();
+            clientsCache = MapBuilder.newMapBuilder(clientsCache).put(clientSettings, clientReference).immutableMap();
+            return clientReference;
+        }
+    }
+
+    /**
+     * Either fetches {@link KmsClientSettings} for a given {@link CryptoMetadata} from cached settings or creates them
+     * by overriding static client settings from {@link #staticClientSettings} with settings found in the crypto metadata.
+     * @param cryptoMetadata Crypto Metadata
+     * @return KmsClientSettings
+     */
+    KmsClientSettings settings(CryptoMetadata cryptoMetadata) {
+        final Settings settings = cryptoMetadata.settings();
+        {
+            final KmsClientSettings existing = derivedClientSettings.get(settings);
+            if (existing != null) {
+                return existing;
+            }
+        }
+        synchronized (this) {
+            final KmsClientSettings existing = derivedClientSettings.get(settings);
+            if (existing != null) {
+                return existing;
+            }
+            final KmsClientSettings newSettings = staticClientSettings.getMetadataSettings(settings);
+            derivedClientSettings = MapBuilder.newMapBuilder(derivedClientSettings).put(settings, newSettings).immutableMap();
+            return newSettings;
+        }
+    }
+
+    /**
+     * Refreshes the settings for the AmazonKMS client. The new client will be build
+     * using these new settings. The old client is usable until released. On release it
+     * will be destroyed instead of being returned to the cache.
+     */
+    public void refreshAndClearCache(KmsClientSettings clientSettings) {
+        // shutdown all unused clients
+        // others will shutdown on their respective release
+        releaseCachedClients();
+        this.staticClientSettings = clientSettings;
+        derivedClientSettings = emptyMap();
+    }
+
+    private synchronized void releaseCachedClients() {
+        // the clients will shutdown when they will not be used anymore
+        for (final AmazonKmsClientReference clientReference : clientsCache.values()) {
+            clientReference.decRef();
+        }
+
+        // clear previously cached clients, they will be build lazily
+        clientsCache = emptyMap();
+        derivedClientSettings = emptyMap();
+    }
+
+    @Override
+    public void close() {
+        releaseCachedClients();
+    }
+
+    // By default, AWS v2 SDK loads a default profile from $USER_HOME, which is restricted. Use the OpenSearch configuration path instead.
+    @SuppressForbidden(reason = "Prevent AWS SDK v2 from using ~/.aws/config and ~/.aws/credentials.")
+    static void setDefaultAwsProfilePath() {
+        if (ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.getStringValue().isEmpty()) {
+            logger.info("setting aws.sharedCredentialsFile={}", System.getProperty("opensearch.path.conf"));
+            System.setProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+        if (ProfileFileSystemSetting.AWS_CONFIG_FILE.getStringValue().isEmpty()) {
+            logger.info("setting aws.sharedCredentialsFile={}", System.getProperty("opensearch.path.conf"));
+            System.setProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+    }
+
+    public MasterKeyProvider createMasterKeyProvider(CryptoMetadata cryptoMetadata) {
+        Settings cryptoSettings = Settings.builder().put(cryptoMetadata.settings()).normalizePrefix("kms.").build();
+        String keyArn = KEY_ARN_SETTING.get(cryptoSettings);
+        if (!Strings.hasText(keyArn)) {
+            throw new IllegalArgumentException("Missing key_arn setting");
+        }
+
+        String kmsEncCtx = ENC_CTX_SETTING.get(cryptoSettings);
+        Map<String, String> encCtx;
+        if (Strings.hasText(kmsEncCtx)) {
+            try {
+                encCtx = Arrays.stream(kmsEncCtx.split(","))
+                    .map(s -> s.split("="))
+                    .collect(Collectors.toMap(e -> e[0].trim(), e -> e[1].trim()));
+            } catch (Exception ex) {
+                throw new IllegalArgumentException(ENC_CTX_SETTING.getKey() + " Format should be: Name1=Value1, Name2=Value2");
+            }
+        } else {
+            encCtx = new HashMap<>();
+        }
+
+        // Verify client creation is successful to early detect any failure.
+        try (AmazonKmsClientReference clientReference = client(cryptoMetadata)) {
+            clientReference.get();
+        }
+
+        return new KmsMasterKeyProvider(encCtx, keyArn, () -> client(cryptoMetadata));
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/SocketAccess.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/SocketAccess.java
new file mode 100644
index 0000000000000..5b026c30017ca
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/SocketAccess.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import org.opensearch.SpecialPermission;
+
+import java.net.SocketPermission;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+/**
+ * This plugin uses aws libraries to connect to Aws services. For these remote calls the plugin needs
+ * {@link SocketPermission} 'connect' to establish connections. This class wraps the operations requiring access in
+ * {@link AccessController#doPrivileged(PrivilegedAction)} blocks.
+ */
+public final class SocketAccess {
+
+    private SocketAccess() {}
+
+    public static <T> T doPrivileged(PrivilegedAction<T> operation) {
+        SpecialPermission.check();
+        return AccessController.doPrivileged(operation);
+    }
+
+    public static void doPrivilegedVoid(Runnable action) {
+        SpecialPermission.check();
+        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
+            action.run();
+            return null;
+        });
+    }
+}
diff --git a/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/package-info.java b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/package-info.java
new file mode 100644
index 0000000000000..787adc32d8941
--- /dev/null
+++ b/plugins/crypto-kms/src/main/java/org/opensearch/crypto/kms/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Crypto plugin to for encryption and decryption use cases.
+ */
+package org.opensearch.crypto.kms;
diff --git a/plugins/crypto-kms/src/main/plugin-metadata/plugin-security.policy b/plugins/crypto-kms/src/main/plugin-metadata/plugin-security.policy
new file mode 100644
index 0000000000000..46fb79010f9ef
--- /dev/null
+++ b/plugins/crypto-kms/src/main/plugin-metadata/plugin-security.policy
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+grant {
+  // needed because of problems in ClientConfiguration
+  // TODO: get these fixed in aws sdk
+  permission java.lang.RuntimePermission "accessDeclaredMembers";
+  permission java.lang.RuntimePermission "getClassLoader";
+  permission java.lang.RuntimePermission "setContextClassLoader";
+  // Needed because of problems in kms client
+  // When no region is set on a kms client instance, the
+  // AWS SDK loads all known partitions from a JSON file and
+  // uses a Jackson's ObjectMapper for that: this one, in
+  // version 2.5.3 with the default binding options, tries
+  // to suppress access checks of ctor/field/method and thus
+  // requires this special permission. AWS must be fixed to
+  // uses Jackson correctly and have the correct modifiers
+  // on binded classes.
+  // TODO: get these fixed in aws sdk
+  // See https://github.com/aws/aws-sdk-java/issues/766
+  permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
+
+  permission java.lang.RuntimePermission "getClassLoader";
+
+  // kms client opens socket connections for to kms
+  permission java.net.SocketPermission "*", "connect,resolve";
+
+  // kms client set Authenticator for proxy username/password
+  permission java.net.NetPermission "setDefaultAuthenticator";
+
+  permission java.util.PropertyPermission "aws.sharedCredentialsFile", "read,write";
+  permission java.util.PropertyPermission "aws.configFile", "read,write";
+  permission java.util.PropertyPermission "aws.region", "read,write";
+  permission java.util.PropertyPermission "aws.accessKeyId", "read,write";
+  permission java.util.PropertyPermission "aws.secretAccessKey", "read,write";
+  permission java.util.PropertyPermission "opensearch.path.conf", "read,write";
+
+  permission java.io.FilePermission "config", "read";
+};
diff --git a/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/AbstractAwsTestCase.java b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/AbstractAwsTestCase.java
new file mode 100644
index 0000000000000..3fe49f9d3b523
--- /dev/null
+++ b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/AbstractAwsTestCase.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.file.Path;
+
+public abstract class AbstractAwsTestCase extends OpenSearchTestCase {
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        setUpAwsProfile();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        resetAwsProfile();
+        super.tearDown();
+    }
+
+    private Path configPath() {
+        return PathUtils.get("config");
+    }
+
+    private String previousOpenSearchPathConf;
+    private String awsRegion;
+    private String awsAccessKeyId;
+    private String awsSecretAccessKey;
+    private String awsSharedCredentialsFile;
+    private String awsConfigFile;
+
+    @SuppressForbidden(reason = "set predictable aws defaults")
+    private void setUpAwsProfile() throws Exception {
+        previousOpenSearchPathConf = SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
+        awsRegion = SocketAccess.doPrivileged(() -> System.setProperty("aws.region", "us-west-2"));
+        awsAccessKeyId = SocketAccess.doPrivileged(() -> System.setProperty("aws.accessKeyId", "aws-access-key-id"));
+        awsSecretAccessKey = SocketAccess.doPrivileged(() -> System.setProperty("aws.secretAccessKey", "aws-secret-access-key"));
+        awsSharedCredentialsFile = System.getProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property());
+        awsConfigFile = System.getProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property());
+        SocketAccess.doPrivilegedVoid(KmsService::setDefaultAwsProfilePath);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetAwsProfile() throws Exception {
+        resetPropertyValue("opensearch.path.conf", previousOpenSearchPathConf);
+        resetPropertyValue("aws.region", awsRegion);
+        resetPropertyValue("aws.accessKeyId", awsAccessKeyId);
+        resetPropertyValue("aws.secretAccessKey", awsSecretAccessKey);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), awsSharedCredentialsFile);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), awsConfigFile);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetPropertyValue(String key, String value) {
+        if (value != null) {
+            SocketAccess.doPrivileged(() -> System.setProperty(key, value));
+        } else {
+            SocketAccess.doPrivileged(() -> System.clearProperty(key));
+        }
+    }
+}
diff --git a/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/CryptoKmsClientSettingsTests.java b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/CryptoKmsClientSettingsTests.java
new file mode 100644
index 0000000000000..842d85faaa677
--- /dev/null
+++ b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/CryptoKmsClientSettingsTests.java
@@ -0,0 +1,164 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.regions.Region;
+
+import org.opensearch.common.settings.MockSecureSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsException;
+import org.opensearch.common.unit.TimeValue;
+
+import java.io.IOException;
+
+public class CryptoKmsClientSettingsTests extends AbstractAwsTestCase {
+
+    public void testNondefaultClientCreatedBySettingItsSettings() {
+        final KmsClientSettings settings = KmsClientSettings.getClientSettings(
+            Settings.builder().put("kms.endpoint", "custom_endpoint").build()
+        );
+
+        assertEquals(settings.endpoint, "custom_endpoint");
+        // Check if defaults are still present
+        assertNotNull(settings.proxyHost);
+    }
+
+    public void testRejectionOfLoneAccessKey() throws IOException {
+        try (final MockSecureSettings secureSettings = new MockSecureSettings()) {
+            secureSettings.setString("kms.access_key", "aws_secret");
+            final SettingsException e = expectThrows(
+                SettingsException.class,
+                () -> KmsClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
+            );
+            assertTrue(e.getMessage().contains("Setting [kms.access_key] is set but [kms.secret_key] is not"));
+        }
+    }
+
+    public void testRejectionOfLoneSecretKey() throws IOException {
+        try (final MockSecureSettings secureSettings = new MockSecureSettings()) {
+            secureSettings.setString("kms.secret_key", "aws_key");
+            final SettingsException e = expectThrows(
+                SettingsException.class,
+                () -> KmsClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
+            );
+            assertTrue(e.getMessage().contains("Setting [kms.secret_key] is set but [kms.access_key] is not"));
+        }
+    }
+
+    public void testRejectionOfLoneSessionToken() throws IOException {
+        try (final MockSecureSettings secureSettings = new MockSecureSettings()) {
+            secureSettings.setString("kms.session_token", "aws_session_token");
+            final SettingsException e = expectThrows(
+                SettingsException.class,
+                () -> KmsClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
+            );
+            assertTrue(e.getMessage().contains("Setting [kms.session_token] is set but [kms.access_key] and [kms.secret_key] are not"));
+        }
+    }
+
+    public void testDefaultEndpoint() {
+        KmsClientSettings baseSettings = KmsClientSettings.getClientSettings(Settings.EMPTY);
+        assertEquals(baseSettings.endpoint, "");
+    }
+
+    public void testDefaultRegion() {
+        final Settings settings = Settings.builder().build();
+        KmsClientSettings baseSettings = KmsClientSettings.getClientSettings(settings);
+        assertEquals(baseSettings.region, "");
+    }
+
+    public void testSpecificRegion() {
+        final Settings settings = Settings.builder().put(KmsClientSettings.REGION_SETTING.getKey(), "us-west-2").build();
+        KmsClientSettings baseSettings = KmsClientSettings.getClientSettings(settings);
+        assertEquals(baseSettings.region, Region.US_WEST_2.toString());
+    }
+
+    public void testSpecificEndpoint() {
+        final Settings settings = Settings.builder().put(KmsClientSettings.ENDPOINT_SETTING.getKey(), "kms.endpoint").build();
+        KmsClientSettings baseSettings = KmsClientSettings.getClientSettings(settings);
+        assertEquals(baseSettings.endpoint, "kms.endpoint");
+    }
+
+    public void testOverrideWithPrefixedMetadataSettings() {
+        overrideWithMetadataSettings("kms.");
+    }
+
+    public void testOverrideWithNoPrefixMetadataSettings() {
+        overrideWithMetadataSettings("");
+    }
+
+    public void overrideWithMetadataSettings(String prefix) {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        String accessKey = "access_key", secretKey = "secret_key", sessionToken = "session_token";
+        secureSettings.setString("kms.access_key", accessKey);
+        secureSettings.setString("kms.secret_key", secretKey);
+        secureSettings.setString("kms.session_token", sessionToken);
+        final KmsClientSettings baseSettings = KmsClientSettings.getClientSettings(
+            Settings.builder().setSecureSettings(secureSettings).build()
+        );
+
+        {
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(Settings.EMPTY);
+            assertEquals(refinedSettings, baseSettings);
+        }
+
+        {
+            final String endpoint = "some.host";
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(
+                Settings.builder().put(prefix + "endpoint", endpoint).build()
+            );
+            assertEquals(refinedSettings.endpoint, endpoint);
+            validateCredsAreStillSame(refinedSettings, accessKey, secretKey, sessionToken);
+        }
+
+        {
+            String region = "eu-west-1";
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(
+                Settings.builder().put(prefix + "region", region).build()
+            );
+            assertEquals(refinedSettings.region, region);
+            validateCredsAreStillSame(refinedSettings, accessKey, secretKey, sessionToken);
+        }
+
+        {
+            String proxyHost = "proxy-host";
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(
+                Settings.builder().put(prefix + "proxy.host", proxyHost).build()
+            );
+            assertEquals(refinedSettings.proxyHost, proxyHost);
+            validateCredsAreStillSame(refinedSettings, accessKey, secretKey, sessionToken);
+        }
+
+        {
+            int proxyPort = 70;
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(
+                Settings.builder().put(prefix + "proxy.port", proxyPort).build()
+            );
+            assertEquals(refinedSettings.proxyPort, proxyPort);
+            validateCredsAreStillSame(refinedSettings, accessKey, secretKey, sessionToken);
+        }
+
+        {
+            TimeValue readTimeout = TimeValue.timeValueMillis(5000);
+            final KmsClientSettings refinedSettings = baseSettings.getMetadataSettings(
+                Settings.builder().put(prefix + "read_timeout", readTimeout).build()
+            );
+            assertEquals(refinedSettings.readTimeoutMillis, readTimeout.getMillis());
+            validateCredsAreStillSame(refinedSettings, accessKey, secretKey, sessionToken);
+        }
+    }
+
+    private void validateCredsAreStillSame(KmsClientSettings refinedSettings, String accessKey, String secretKey, String sessionToken) {
+        AwsSessionCredentials credentials = (AwsSessionCredentials) refinedSettings.credentials;
+        assertEquals(credentials.accessKeyId(), accessKey);
+        assertEquals(credentials.secretAccessKey(), secretKey);
+        assertEquals(credentials.sessionToken(), sessionToken);
+    }
+}
diff --git a/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/KmsServiceTests.java b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/KmsServiceTests.java
new file mode 100644
index 0000000000000..1424cce473592
--- /dev/null
+++ b/plugins/crypto-kms/src/test/java/org/opensearch/crypto/kms/KmsServiceTests.java
@@ -0,0 +1,255 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto.kms;
+
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+import software.amazon.awssdk.services.kms.KmsClient;
+
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.settings.MockSecureSettings;
+import org.opensearch.common.settings.Settings;
+
+public class KmsServiceTests extends AbstractAwsTestCase {
+    private final CryptoMetadata cryptoMetadata = new CryptoMetadata("kp1", "kp2", Settings.EMPTY);
+
+    public void testAWSDefaultConfiguration() {
+        try (KmsService kmsService = new KmsService()) {
+            // proxy configuration
+            final ProxyConfiguration proxyConfiguration = kmsService.buildProxyConfiguration(
+                KmsClientSettings.getClientSettings(Settings.EMPTY)
+            );
+
+            assertNull(proxyConfiguration.scheme());
+            assertNull(proxyConfiguration.host());
+            assertEquals(proxyConfiguration.port(), 0);
+            assertNull(proxyConfiguration.username());
+            assertNull(proxyConfiguration.password());
+
+            // retry policy
+            RetryPolicy retryPolicyConfiguration = SocketAccess.doPrivileged(kmsService::buildRetryPolicy);
+
+            assertEquals(retryPolicyConfiguration.numRetries().intValue(), 10);
+
+            ClientOverrideConfiguration clientOverrideConfiguration = SocketAccess.doPrivileged(kmsService::buildOverrideConfiguration);
+            assertTrue(clientOverrideConfiguration.retryPolicy().isPresent());
+            assertEquals(clientOverrideConfiguration.retryPolicy().get().numRetries().intValue(), 10);
+        }
+    }
+
+    public void testAWSConfigurationWithAwsSettings() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("kms.proxy.username", "aws_proxy_username");
+        secureSettings.setString("kms.proxy.password", "aws_proxy_password");
+
+        final Settings settings = Settings.builder()
+            // NOTE: a host cannot contain the _ character when parsed by URI, hence aws-proxy-host and not aws_proxy_host
+            .put("kms.proxy.host", "aws-proxy-host")
+            .put("kms.proxy.port", 8080)
+            .put("kms.read_timeout", "10s")
+            .setSecureSettings(secureSettings)
+            .build();
+
+        try (KmsService kmsService = new KmsService()) {
+            // proxy configuration
+            final ProxyConfiguration proxyConfiguration = SocketAccess.doPrivileged(
+                () -> kmsService.buildProxyConfiguration(KmsClientSettings.getClientSettings(settings))
+            );
+
+            assertEquals(proxyConfiguration.host(), "aws-proxy-host");
+            assertEquals(proxyConfiguration.port(), 8080);
+            assertEquals(proxyConfiguration.username(), "aws_proxy_username");
+            assertEquals(proxyConfiguration.password(), "aws_proxy_password");
+
+            // retry policy
+            RetryPolicy retryPolicyConfiguration = SocketAccess.doPrivileged(kmsService::buildRetryPolicy);
+            assertEquals(retryPolicyConfiguration.numRetries().intValue(), 10);
+
+            ClientOverrideConfiguration clientOverrideConfiguration = SocketAccess.doPrivileged(kmsService::buildOverrideConfiguration);
+            assertTrue(clientOverrideConfiguration.retryPolicy().isPresent());
+            assertEquals(clientOverrideConfiguration.retryPolicy().get().numRetries().intValue(), 10);
+        }
+    }
+
+    public void testClientSettingsReInit() {
+        final MockSecureSettings mockSecure1 = new MockSecureSettings();
+        mockSecure1.setString(KmsClientSettings.ACCESS_KEY_SETTING.getKey(), "kms_access_1");
+        mockSecure1.setString(KmsClientSettings.SECRET_KEY_SETTING.getKey(), "kms_secret_1");
+        final boolean mockSecure1HasSessionToken = randomBoolean();
+        if (mockSecure1HasSessionToken) {
+            mockSecure1.setString(KmsClientSettings.SESSION_TOKEN_SETTING.getKey(), "kms_session_token_1");
+        }
+        mockSecure1.setString(KmsClientSettings.PROXY_USERNAME_SETTING.getKey(), "proxy_username_1");
+        mockSecure1.setString(KmsClientSettings.PROXY_PASSWORD_SETTING.getKey(), "proxy_password_1");
+        final Settings settings1 = Settings.builder()
+            .put(KmsClientSettings.PROXY_HOST_SETTING.getKey(), "proxy-host-1")
+            .put(KmsClientSettings.PROXY_PORT_SETTING.getKey(), 881)
+            .put(KmsClientSettings.REGION_SETTING.getKey(), "kms_region")
+            .put(KmsClientSettings.ENDPOINT_SETTING.getKey(), "kms_endpoint_1")
+            .setSecureSettings(mockSecure1)
+            .build();
+        final MockSecureSettings mockSecure2 = new MockSecureSettings();
+        mockSecure2.setString(KmsClientSettings.ACCESS_KEY_SETTING.getKey(), "kms_access_2");
+        mockSecure2.setString(KmsClientSettings.SECRET_KEY_SETTING.getKey(), "kms_secret_2");
+        final boolean mockSecure2HasSessionToken = randomBoolean();
+        if (mockSecure2HasSessionToken) {
+            mockSecure2.setString(KmsClientSettings.SESSION_TOKEN_SETTING.getKey(), "kms_session_token_2");
+        }
+        mockSecure2.setString(KmsClientSettings.PROXY_USERNAME_SETTING.getKey(), "proxy_username_2");
+        mockSecure2.setString(KmsClientSettings.PROXY_PASSWORD_SETTING.getKey(), "proxy_password_2");
+        final Settings settings2 = Settings.builder()
+            .put(KmsClientSettings.PROXY_HOST_SETTING.getKey(), "proxy-host-2")
+            .put(KmsClientSettings.PROXY_PORT_SETTING.getKey(), 882)
+            .put(KmsClientSettings.REGION_SETTING.getKey(), "kms_region")
+            .put(KmsClientSettings.ENDPOINT_SETTING.getKey(), "kms_endpoint_2")
+            .setSecureSettings(mockSecure2)
+            .build();
+        try (CryptoKmsPluginMockTest plugin = new CryptoKmsPluginMockTest(settings1)) {
+            try (AmazonKmsClientReference clientReference = plugin.kmsService.client(cryptoMetadata)) {
+                {
+                    final MockKmsClientTest mockKmsClientTest = (MockKmsClientTest) clientReference.get();
+                    assertEquals(mockKmsClientTest.endpoint, "kms_endpoint_1");
+
+                    final AwsCredentials credentials = mockKmsClientTest.credentials.resolveCredentials();
+                    assertEquals(credentials.accessKeyId(), "kms_access_1");
+                    assertEquals(credentials.secretAccessKey(), "kms_secret_1");
+                    if (mockSecure1HasSessionToken) {
+                        assertTrue(credentials instanceof AwsSessionCredentials);
+                        assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "kms_session_token_1");
+                    } else {
+                        assertTrue(credentials instanceof AwsBasicCredentials);
+                    }
+
+                    assertEquals(
+                        mockKmsClientTest.proxyConfiguration.toString(),
+                        "ProxyConfiguration(endpoint=https://proxy-host-1:881, username=proxy_username_1, preemptiveBasicAuthenticationEnabled=false)"
+                    );
+                    assertEquals(mockKmsClientTest.proxyConfiguration.host(), "proxy-host-1");
+                    assertEquals(mockKmsClientTest.proxyConfiguration.port(), 881);
+                    assertEquals(mockKmsClientTest.proxyConfiguration.username(), "proxy_username_1");
+                    assertEquals(mockKmsClientTest.proxyConfiguration.password(), "proxy_password_1");
+                }
+                // reload secure settings2
+                plugin.reload(settings2);
+                // client is not released, it is still using the old settings
+                {
+                    final MockKmsClientTest mockKmsClientTest = (MockKmsClientTest) clientReference.get();
+                    assertEquals(mockKmsClientTest.endpoint, "kms_endpoint_1");
+
+                    final AwsCredentials credentials = ((MockKmsClientTest) clientReference.get()).credentials.resolveCredentials();
+                    if (mockSecure1HasSessionToken) {
+                        assertTrue(credentials instanceof AwsSessionCredentials);
+                        assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "kms_session_token_1");
+                    } else {
+                        assertTrue(credentials instanceof AwsBasicCredentials);
+                    }
+
+                    assertEquals(
+                        mockKmsClientTest.proxyConfiguration.toString(),
+                        "ProxyConfiguration(endpoint=https://proxy-host-1:881, username=proxy_username_1, preemptiveBasicAuthenticationEnabled=false)"
+                    );
+                    assertEquals(mockKmsClientTest.proxyConfiguration.host(), "proxy-host-1");
+                    assertEquals(mockKmsClientTest.proxyConfiguration.port(), 881);
+                    assertEquals(mockKmsClientTest.proxyConfiguration.username(), "proxy_username_1");
+                    assertEquals(mockKmsClientTest.proxyConfiguration.password(), "proxy_password_1");
+                }
+            }
+            try (AmazonKmsClientReference clientReference = plugin.kmsService.client(cryptoMetadata)) {
+                final MockKmsClientTest mockKmsClientTest = (MockKmsClientTest) clientReference.get();
+                assertEquals(mockKmsClientTest.endpoint, "kms_endpoint_2");
+
+                final AwsCredentials credentials = ((MockKmsClientTest) clientReference.get()).credentials.resolveCredentials();
+                assertEquals(credentials.accessKeyId(), "kms_access_2");
+                assertEquals(credentials.secretAccessKey(), "kms_secret_2");
+                if (mockSecure2HasSessionToken) {
+                    assertTrue(credentials instanceof AwsSessionCredentials);
+                    assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "kms_session_token_2");
+                } else {
+                    assertTrue(credentials instanceof AwsBasicCredentials);
+                }
+
+                assertEquals(
+                    mockKmsClientTest.proxyConfiguration.toString(),
+                    "ProxyConfiguration(endpoint=https://proxy-host-2:882, username=proxy_username_2, preemptiveBasicAuthenticationEnabled=false)"
+                );
+                assertEquals(mockKmsClientTest.proxyConfiguration.host(), "proxy-host-2");
+                assertEquals(mockKmsClientTest.proxyConfiguration.port(), 882);
+                assertEquals(mockKmsClientTest.proxyConfiguration.username(), "proxy_username_2");
+                assertEquals(mockKmsClientTest.proxyConfiguration.password(), "proxy_password_2");
+            }
+        }
+    }
+
+    static class CryptoKmsPluginMockTest extends CryptoKmsPlugin {
+
+        CryptoKmsPluginMockTest(Settings settings) {
+            super(settings, new KmsService() {
+                @Override
+                protected KmsClient buildClient(
+                    AwsCredentialsProvider credentials,
+                    ProxyConfiguration proxyConfiguration,
+                    ClientOverrideConfiguration overrideConfiguration,
+                    String endpoint,
+                    String region,
+                    long readTimeoutMillis
+                ) {
+                    return new MockKmsClientTest(
+                        credentials,
+                        proxyConfiguration,
+                        overrideConfiguration,
+                        endpoint,
+                        region,
+                        readTimeoutMillis
+                    );
+                }
+            });
+        }
+    }
+
+    static class MockKmsClientTest implements KmsClient {
+
+        String endpoint;
+        final String region;
+        final AwsCredentialsProvider credentials;
+        final ClientOverrideConfiguration clientOverrideConfiguration;
+        final ProxyConfiguration proxyConfiguration;
+        final long readTimeoutMillis;
+
+        MockKmsClientTest(
+            AwsCredentialsProvider credentials,
+            ProxyConfiguration proxyConfiguration,
+            ClientOverrideConfiguration clientOverrideConfiguration,
+            String endpoint,
+            String region,
+            long readTimeoutMillis
+        ) {
+            this.credentials = credentials;
+            this.proxyConfiguration = proxyConfiguration;
+            this.clientOverrideConfiguration = clientOverrideConfiguration;
+            this.endpoint = endpoint;
+            this.region = region;
+            this.readTimeoutMillis = readTimeoutMillis;
+        }
+
+        @Override
+        public String serviceName() {
+            return "kms";
+        }
+
+        @Override
+        public void close() {
+            // ignore
+        }
+    }
+}
diff --git a/plugins/crypto-kms/src/yamlRestTest/java/org/opensearch/kms/CloudAwsClientYamlTestSuiteIT.java b/plugins/crypto-kms/src/yamlRestTest/java/org/opensearch/kms/CloudAwsClientYamlTestSuiteIT.java
new file mode 100644
index 0000000000000..87e6691e40855
--- /dev/null
+++ b/plugins/crypto-kms/src/yamlRestTest/java/org/opensearch/kms/CloudAwsClientYamlTestSuiteIT.java
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.kms;
+
+import com.carrotsearch.randomizedtesting.annotations.Name;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
+import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
+
+public class CloudAwsClientYamlTestSuiteIT extends OpenSearchClientYamlSuiteTestCase {
+
+    public CloudAwsClientYamlTestSuiteIT(@Name("yaml") ClientYamlTestCandidate testCandidate) {
+        super(testCandidate);
+    }
+
+    @ParametersFactory
+    public static Iterable<Object[]> parameters() throws Exception {
+        return OpenSearchClientYamlSuiteTestCase.createParameters();
+    }
+}
diff --git a/plugins/crypto-kms/src/yamlRestTest/resources/rest-api-spec/test/kms/10_basic.yml b/plugins/crypto-kms/src/yamlRestTest/resources/rest-api-spec/test/kms/10_basic.yml
new file mode 100644
index 0000000000000..3d6c3056a6975
--- /dev/null
+++ b/plugins/crypto-kms/src/yamlRestTest/resources/rest-api-spec/test/kms/10_basic.yml
@@ -0,0 +1,16 @@
+# Integration tests for KMS component
+#
+"KMS loaded":
+    - skip:
+        reason: "contains is a newly added assertion"
+        features: contains
+    - do:
+        cluster.state: {}
+
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
+
+    - do:
+        nodes.info: {}
+
+    - contains:  { nodes.$cluster_manager.plugins: { name: crypto-kms } }
diff --git a/plugins/discovery-azure-classic/build.gradle b/plugins/discovery-azure-classic/build.gradle
index 28cbc647ac31a..1fed446016647 100644
--- a/plugins/discovery-azure-classic/build.gradle
+++ b/plugins/discovery-azure-classic/build.gradle
@@ -53,13 +53,13 @@ dependencies {
   api "org.apache.logging.log4j:log4j-1.2-api:${versions.log4j}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
   api "commons-lang:commons-lang:2.6"
-  api "commons-io:commons-io:2.11.0"
+  api "commons-io:commons-io:2.13.0"
   api 'javax.mail:mail:1.4.7'
   api 'javax.inject:javax.inject:1'
   api "com.sun.jersey:jersey-client:${versions.jersey}"
   api "com.sun.jersey:jersey-core:${versions.jersey}"
   api "com.sun.jersey:jersey-json:${versions.jersey}"
-  api 'org.codehaus.jettison:jettison:1.1'
+  api "org.codehaus.jettison:jettison:${versions.jettison}"
   api 'com.sun.xml.bind:jaxb-impl:2.2.3-1'
 
   // HACK: javax.xml.bind was removed from default modules in java 9, so we pull the api in here,
diff --git a/plugins/discovery-azure-classic/licenses/commons-codec-1.13.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/discovery-azure-classic/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/commons-codec-1.15.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/commons-io-2.11.0.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-io-2.11.0.jar.sha1
deleted file mode 100644
index 8adec30bade49..0000000000000
--- a/plugins/discovery-azure-classic/licenses/commons-io-2.11.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a2503f302b11ebde7ebc3df41daebe0e4eea3689
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/commons-io-2.13.0.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-io-2.13.0.jar.sha1
new file mode 100644
index 0000000000000..c165136eb5822
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/commons-io-2.13.0.jar.sha1
@@ -0,0 +1 @@
+8bb2bc9b4df17e2411533a0708a69f983bf5e83b
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index c8756c438320f..0000000000000
--- a/plugins/discovery-azure-classic/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
diff --git a/plugins/discovery-azure-classic/licenses/commons-logging-1.2.jar.sha1 b/plugins/discovery-azure-classic/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/commons-logging-LICENSE.txt b/plugins/discovery-azure-classic/licenses/commons-logging-LICENSE.txt
index d645695673349..57bc88a15a0ee 100644
--- a/plugins/discovery-azure-classic/licenses/commons-logging-LICENSE.txt
+++ b/plugins/discovery-azure-classic/licenses/commons-logging-LICENSE.txt
@@ -1,4 +1,3 @@
-
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -200,3 +199,4 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
+
diff --git a/plugins/discovery-azure-classic/licenses/commons-logging-NOTICE.txt b/plugins/discovery-azure-classic/licenses/commons-logging-NOTICE.txt
index d3d6e140ce4f3..72eb32a902458 100644
--- a/plugins/discovery-azure-classic/licenses/commons-logging-NOTICE.txt
+++ b/plugins/discovery-azure-classic/licenses/commons-logging-NOTICE.txt
@@ -1,5 +1,5 @@
-Apache Commons Logging
-Copyright 2003-2014 The Apache Software Foundation
+Apache Commons CLI
+Copyright 2001-2009 The Apache Software Foundation
 
-This product includes software developed at
+This product includes software developed by
 The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/discovery-azure-classic/licenses/httpclient-4.5.13.jar.sha1 b/plugins/discovery-azure-classic/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/plugins/discovery-azure-classic/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/httpclient-4.5.14.jar.sha1 b/plugins/discovery-azure-classic/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/httpcore-4.4.12.jar.sha1 b/plugins/discovery-azure-classic/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/plugins/discovery-azure-classic/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/httpcore-4.4.16.jar.sha1 b/plugins/discovery-azure-classic/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/jettison-1.1.jar.sha1 b/plugins/discovery-azure-classic/licenses/jettison-1.1.jar.sha1
deleted file mode 100644
index 53133f3b018e6..0000000000000
--- a/plugins/discovery-azure-classic/licenses/jettison-1.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1a01a2a1218fcf9faa2cc2a6ced025bdea687262
diff --git a/plugins/discovery-azure-classic/licenses/jettison-1.5.4.jar.sha1 b/plugins/discovery-azure-classic/licenses/jettison-1.5.4.jar.sha1
new file mode 100644
index 0000000000000..a87b7691bfce8
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/jettison-1.5.4.jar.sha1
@@ -0,0 +1 @@
+174ca56c411b05aec323d8f53e66709c0d28b337
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.17.1.jar.sha1 b/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.17.1.jar.sha1
deleted file mode 100644
index 23aa5c60bd596..0000000000000
--- a/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-db3a7e7f07e878b92ac4a8f1100bee8325d5713a
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/discovery-azure-classic/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/cloud/azure/classic/AbstractAzureComputeServiceTestCase.java b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/cloud/azure/classic/AbstractAzureComputeServiceTestCase.java
index f95f358532bac..9c4b577df3e5f 100644
--- a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/cloud/azure/classic/AbstractAzureComputeServiceTestCase.java
+++ b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/cloud/azure/classic/AbstractAzureComputeServiceTestCase.java
@@ -39,7 +39,6 @@
 import com.microsoft.windowsazure.management.compute.models.RoleInstance;
 import com.microsoft.windowsazure.management.compute.models.RoleInstancePowerState;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
-
 import org.opensearch.cloud.azure.classic.management.AzureComputeService;
 import org.opensearch.cloud.azure.classic.management.AzureComputeService.Discovery;
 import org.opensearch.cloud.azure.classic.management.AzureComputeService.Management;
@@ -47,13 +46,12 @@
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.azure.classic.AzureSeedHostsProvider;
 import org.opensearch.plugin.discovery.azure.classic.AzureDiscoveryPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.transport.TransportService;
-
 import org.junit.After;
 
 import java.util.ArrayList;
@@ -63,7 +61,7 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
-import static org.opensearch.common.util.CollectionUtils.newSingletonArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.newSingletonArrayList;
 import static org.opensearch.discovery.DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING;
 
 public abstract class AbstractAzureComputeServiceTestCase extends OpenSearchIntegTestCase {
diff --git a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureDiscoveryClusterFormationTests.java b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureDiscoveryClusterFormationTests.java
index c4f533fd2ee36..ad622e68f5ccb 100644
--- a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureDiscoveryClusterFormationTests.java
+++ b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureDiscoveryClusterFormationTests.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.discovery.azure.classic;
 
-import com.microsoft.windowsazure.management.compute.models.DeploymentSlot;
-import com.microsoft.windowsazure.management.compute.models.DeploymentStatus;
 import com.sun.net.httpserver.Headers;
 import com.sun.net.httpserver.HttpsConfigurator;
 import com.sun.net.httpserver.HttpsServer;
+
+import com.microsoft.windowsazure.management.compute.models.DeploymentSlot;
+import com.microsoft.windowsazure.management.compute.models.DeploymentStatus;
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.cloud.azure.classic.management.AzureComputeService;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.env.Environment;
 import org.opensearch.node.Node;
@@ -63,10 +63,12 @@
 import javax.xml.stream.XMLOutputFactory;
 import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.XMLStreamWriter;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.StringWriter;
+import java.lang.Runtime.Version;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.nio.charset.StandardCharsets;
@@ -295,15 +297,13 @@ private static SSLContext getSSLContext() throws Exception {
      * 12.0.1 so we pin to TLSv1.2 when running on an earlier JDK
      */
     private static String getProtocol() {
-        if (JavaVersion.current().compareTo(JavaVersion.parse("11")) < 0) {
-            return "TLS";
-        } else if (JavaVersion.current().compareTo(JavaVersion.parse("12")) < 0) {
+        if (Runtime.version().compareTo(Version.parse("12")) < 0) {
             return "TLSv1.2";
         } else {
-            JavaVersion full = AccessController.doPrivileged(
-                (PrivilegedAction<JavaVersion>) () -> JavaVersion.parse(System.getProperty("java.version"))
+            Version full = AccessController.doPrivileged(
+                (PrivilegedAction<Version>) () -> Version.parse(System.getProperty("java.version"))
             );
-            if (full.compareTo(JavaVersion.parse("12.0.1")) < 0) {
+            if (full.compareTo(Version.parse("12.0.1")) < 0) {
                 return "TLSv1.2";
             }
         }
diff --git a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureSimpleTests.java b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureSimpleTests.java
index f4268443a707a..4c2dda180eda6 100644
--- a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureSimpleTests.java
+++ b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureSimpleTests.java
@@ -50,7 +50,9 @@ public void testOneNodeShouldRunUsingPrivateIp() {
 
         final String node1 = internalCluster().startNode(settings);
         registerAzureNode(node1);
-        assertNotNull(client().admin().cluster().prepareState().setMasterNodeTimeout("1s").get().getState().nodes().getMasterNodeId());
+        assertNotNull(
+            client().admin().cluster().prepareState().setClusterManagerNodeTimeout("1s").get().getState().nodes().getClusterManagerNodeId()
+        );
 
         // We expect having 1 node as part of the cluster, let's test that
         assertNumberOfNodes(1);
@@ -63,7 +65,9 @@ public void testOneNodeShouldRunUsingPublicIp() {
 
         final String node1 = internalCluster().startNode(settings);
         registerAzureNode(node1);
-        assertNotNull(client().admin().cluster().prepareState().setMasterNodeTimeout("1s").get().getState().nodes().getMasterNodeId());
+        assertNotNull(
+            client().admin().cluster().prepareState().setClusterManagerNodeTimeout("1s").get().getState().nodes().getClusterManagerNodeId()
+        );
 
         // We expect having 1 node as part of the cluster, let's test that
         assertNumberOfNodes(1);
diff --git a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureTwoStartedNodesTests.java b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureTwoStartedNodesTests.java
index d8ea8a91fd21d..10e8a65e906cc 100644
--- a/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureTwoStartedNodesTests.java
+++ b/plugins/discovery-azure-classic/src/internalClusterTest/java/org/opensearch/discovery/azure/classic/AzureTwoStartedNodesTests.java
@@ -53,12 +53,16 @@ public void testTwoNodesShouldRunUsingPrivateOrPublicIp() {
         logger.info("--> start first node");
         final String node1 = internalCluster().startNode(settings);
         registerAzureNode(node1);
-        assertNotNull(client().admin().cluster().prepareState().setMasterNodeTimeout("1s").get().getState().nodes().getMasterNodeId());
+        assertNotNull(
+            client().admin().cluster().prepareState().setClusterManagerNodeTimeout("1s").get().getState().nodes().getClusterManagerNodeId()
+        );
 
         logger.info("--> start another node");
         final String node2 = internalCluster().startNode(settings);
         registerAzureNode(node2);
-        assertNotNull(client().admin().cluster().prepareState().setMasterNodeTimeout("1s").get().getState().nodes().getMasterNodeId());
+        assertNotNull(
+            client().admin().cluster().prepareState().setClusterManagerNodeTimeout("1s").get().getState().nodes().getClusterManagerNodeId()
+        );
 
         // We expect having 2 nodes as part of the cluster, let's test that
         assertNumberOfNodes(2);
diff --git a/plugins/discovery-azure-classic/src/main/java/org/opensearch/cloud/azure/classic/management/AzureComputeServiceImpl.java b/plugins/discovery-azure-classic/src/main/java/org/opensearch/cloud/azure/classic/management/AzureComputeServiceImpl.java
index 6a8b8d83f539b..1bac80e576199 100644
--- a/plugins/discovery-azure-classic/src/main/java/org/opensearch/cloud/azure/classic/management/AzureComputeServiceImpl.java
+++ b/plugins/discovery-azure-classic/src/main/java/org/opensearch/cloud/azure/classic/management/AzureComputeServiceImpl.java
@@ -32,12 +32,6 @@
 
 package org.opensearch.cloud.azure.classic.management;
 
-import java.io.IOException;
-import java.security.AccessController;
-import java.security.PrivilegedActionException;
-import java.security.PrivilegedExceptionAction;
-import java.util.ServiceLoader;
-
 import com.microsoft.windowsazure.Configuration;
 import com.microsoft.windowsazure.core.Builder;
 import com.microsoft.windowsazure.core.DefaultBuilder;
@@ -51,10 +45,16 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.SpecialPermission;
 import org.opensearch.cloud.azure.classic.AzureServiceRemoteException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+
+import java.io.IOException;
+import java.security.AccessController;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.util.ServiceLoader;
 
 public class AzureComputeServiceImpl extends AbstractLifecycleComponent implements AzureComputeService {
     private static final Logger logger = LogManager.getLogger(AzureComputeServiceImpl.class);
diff --git a/plugins/discovery-azure-classic/src/main/java/org/opensearch/discovery/azure/classic/AzureSeedHostsProvider.java b/plugins/discovery-azure-classic/src/main/java/org/opensearch/discovery/azure/classic/AzureSeedHostsProvider.java
index 0fe6904e83242..9d5958fa2d40d 100644
--- a/plugins/discovery-azure-classic/src/main/java/org/opensearch/discovery/azure/classic/AzureSeedHostsProvider.java
+++ b/plugins/discovery-azure-classic/src/main/java/org/opensearch/discovery/azure/classic/AzureSeedHostsProvider.java
@@ -37,20 +37,19 @@
 import com.microsoft.windowsazure.management.compute.models.HostedServiceGetDetailedResponse;
 import com.microsoft.windowsazure.management.compute.models.InstanceEndpoint;
 import com.microsoft.windowsazure.management.compute.models.RoleInstance;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cloud.azure.classic.AzureServiceDisableException;
 import org.opensearch.cloud.azure.classic.AzureServiceRemoteException;
 import org.opensearch.cloud.azure.classic.management.AzureComputeService;
 import org.opensearch.cloud.azure.classic.management.AzureComputeService.Discovery;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.transport.TransportService;
 
diff --git a/plugins/discovery-azure-classic/src/yamlRestTest/resources/rest-api-spec/test/discovery_azure_classic/10_basic.yml b/plugins/discovery-azure-classic/src/yamlRestTest/resources/rest-api-spec/test/discovery_azure_classic/10_basic.yml
index 39aa9929f8a92..73523d17bbfb9 100644
--- a/plugins/discovery-azure-classic/src/yamlRestTest/resources/rest-api-spec/test/discovery_azure_classic/10_basic.yml
+++ b/plugins/discovery-azure-classic/src/yamlRestTest/resources/rest-api-spec/test/discovery_azure_classic/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: discovery-azure-classic } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: discovery-azure-classic } }
diff --git a/plugins/discovery-ec2/README.md b/plugins/discovery-ec2/README.md
new file mode 100644
index 0000000000000..6daeb6305b988
--- /dev/null
+++ b/plugins/discovery-ec2/README.md
@@ -0,0 +1,94 @@
+# discovery-ec2
+
+The discovery-ec2 plugin allows OpenSearch to find the master-eligible nodes in a cluster running on AWS EC2 by querying the AWS Instance Metadata Service ([IMDS](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html)) API for the addresses of the EC2 instances running these nodes.
+
+This is typically configured as follows in `opensearch.yml`.
+
+```yml
+cluster.initial_cluster_manager_nodes: ["seed"]
+discovery.seed_providers: ec2
+discovery.ec2.tag.role: my-cluster-manager
+```
+
+The implementation in the discovery-ec2 plugin queries for instances of a given type (e.g. private or public IP), with a tag, or running in a specific availability zone.
+
+## Testing
+
+### Unit and Integration Tests
+
+```
+./gradlew :plugins:discovery-ec2:check
+```
+
+### Manual Testing
+
+The following instructions manually exercise the plugin.
+
+Setup a 5-node (Ubuntu) cluster on EC2, with 3 of them tagged with `role: my-cluster-manager`, and a custom TCP rule to expose ports 9200 to 9300 to allow TCP traffic. Default EC2 configuration only allows SSH TCP traffic and hence only exposes port 22.
+
+Set the following properties.
+
+- `network.host`: Set this to the IP of the eth0 network adapter, can be fetched by `ipconfig` or by running `hostname -I` on Linux hosts.
+- `discovery.seed_hosts`: List of all nodes in the cluster.
+- `cluster.initial_cluster_manager_nodes`: List of all initial cluster manager nodes.
+- `discovery.seed_providers`: Set this to `ec2` for EC2 IMDS based discovery.
+- `discovery.ec2.tag.role: my-cluster-manager`: Filter out only those nodes with value `my-cluster-manager` for the `role` tag.
+- `discovery.ec2.region`: Optionally set to your region, e.g. `us-east-1`, by default the plugin uses the region of the current EC2 instance.
+
+While sending the request to IMDS, specified discovery settings for finding master-eligible nodes are being set. You will see the following in the logs.
+
+```
+[2023-05-31T15:22:39,274][DEBUG][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] using host_type [private_ip], tags [{role=[my-cluster-manager]}], groups [[]] with any_group [true], availability_zones [[]]
+```
+
+The nodes getting added as eligible masters are ones with the role tag set to `my-cluster-manager`.
+
+```
+[2023-05-31T15:23:03,676][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] finding seed nodes...
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-01fa1736e8566c693, address 172.31.73.184, transport_address 172.31.73.184:9300
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-03d70a4521045cc3b, address 172.31.74.169, transport_address 172.31.74.169:9300
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-0c6ffdd10ebd3c2f1, address 172.31.74.156, transport_address 172.31.74.156:9300
+```
+
+## Troubleshooting
+
+### Trace Level Logs
+
+Enable `TRACE`-level logging in `opensearch.yml` to see more output.
+
+```yml
+logger.org.opensearch.discovery.ec2: trace
+```
+
+### Sample IMDS Query
+
+You may need to query IMDS without running OpenSearch. Use [this sample](https://github.com/dblock/aws-imds-sample) or copy the following code that makes a query to IMDS that looks for `running`, `pending` or `stopped` instances.
+
+```java
+DefaultCredentialsProvider credentialsProviderChain = DefaultCredentialsProvider.create();
+
+RetryPolicy retryPolicy = RetryPolicy.builder()
+  .numRetries(10)
+  .build();
+
+Ec2Client client = Ec2Client.builder()
+  .httpClientBuilder(ApacheHttpClient.builder())
+  .credentialsProvider(credentialsProviderChain)
+  .build();
+
+DescribeInstancesRequest describeInstancesRequest = DescribeInstancesRequest.builder()
+  .filters(
+    Filter.builder()
+      .name("instance-state-name")
+      .values("running", "pending", "stopped")
+      .build()
+  ).build();
+
+DescribeInstancesResponse describeInstancesResponse = client.describeInstances(describeInstancesRequest);
+for (final Reservation reservation : describeInstancesResponse.reservations()) {
+  System.out.println(reservation.reservationId());
+  for (final Instance instance : reservation.instances()) {
+    System.out.println("\t" + instance.publicDnsName());
+  }
+}
+```
diff --git a/plugins/discovery-ec2/build.gradle b/plugins/discovery-ec2/build.gradle
index 7998e0861c7b1..9c9f64f09b915 100644
--- a/plugins/discovery-ec2/build.gradle
+++ b/plugins/discovery-ec2/build.gradle
@@ -38,20 +38,33 @@ opensearchplugin {
   classname 'org.opensearch.discovery.ec2.Ec2DiscoveryPlugin'
 }
 
-versions << [
-  'aws': '1.11.749'
-]
-
 dependencies {
-  api "com.amazonaws:aws-java-sdk-ec2:${versions.aws}"
-  api "com.amazonaws:aws-java-sdk-core:${versions.aws}"
+  api "software.amazon.awssdk:sdk-core:${versions.aws}"
+  api "software.amazon.awssdk:aws-core:${versions.aws}"
+  api "software.amazon.awssdk:utils:${versions.aws}"
+  api "software.amazon.awssdk:auth:${versions.aws}"
+  api "software.amazon.awssdk:ec2:${versions.aws}"
+  api "software.amazon.awssdk:http-client-spi:${versions.aws}"
+  api "software.amazon.awssdk:apache-client:${versions.aws}"
+  api "software.amazon.awssdk:regions:${versions.aws}"
+  api "software.amazon.awssdk:profiles:${versions.aws}"
+  api "software.amazon.awssdk:endpoints-spi:${versions.aws}"
+  api "software.amazon.awssdk:annotations:${versions.aws}"
+  api "software.amazon.awssdk:metrics-spi:${versions.aws}"
+  api "software.amazon.awssdk:json-utils:${versions.aws}"
+  api "software.amazon.awssdk:protocol-core:${versions.aws}"
+  api "software.amazon.awssdk:aws-query-protocol:${versions.aws}"
+  api "software.amazon.awssdk:aws-json-protocol:${versions.aws}"
+  api "software.amazon.awssdk:third-party-jackson-core:${versions.aws}"
   api "org.apache.httpcomponents:httpclient:${versions.httpclient}"
   api "org.apache.httpcomponents:httpcore:${versions.httpcore}"
   api "commons-logging:commons-logging:${versions.commonslogging}"
   api "org.apache.logging.log4j:log4j-1.2-api:${versions.log4j}"
+  api "org.slf4j:slf4j-api:${versions.slf4j}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
-  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
   api "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
+  api "org.reactivestreams:reactive-streams:${versions.reactivestreams}"
 }
 
 restResources {
@@ -61,7 +74,7 @@ restResources {
 }
 
 tasks.named("dependencyLicenses").configure {
-  mapping from: /aws-java-sdk-.*/, to: 'aws-java-sdk'
+  mapping from: /software.amazon.awssdk-.*/, to: 'software.amazon.awssdk'
   mapping from: /jackson-.*/, to: 'jackson'
 }
 
@@ -94,7 +107,8 @@ tasks.register("writeTestJavaPolicy") {
           "  permission org.bouncycastle.crypto.CryptoServicesPermission \"exportSecretKey\";",
           "  permission org.bouncycastle.crypto.CryptoServicesPermission \"exportPrivateKey\";",
           "  permission java.io.FilePermission \"\${javax.net.ssl.trustStore}\", \"read\";",
-          "  permission java.util.PropertyPermission \"com.amazonaws.sdk.ec2MetadataServiceEndpointOverride\", \"write\";",
+          "  permission java.util.PropertyPermission \"aws.ec2MetadataServiceEndpoint\", \"write\";",
+          "  permission java.io.FilePermission \"config\", \"read\";",
           "};"
         ].join("\n")
       )
@@ -102,7 +116,8 @@ tasks.register("writeTestJavaPolicy") {
       javaPolicy.write(
         [
           "grant {",
-          "  permission java.util.PropertyPermission \"com.amazonaws.sdk.ec2MetadataServiceEndpointOverride\", \"write\";",
+          "  permission java.util.PropertyPermission \"aws.ec2MetadataServiceEndpoint\", \"write\";",
+          "  permission java.io.FilePermission \"config\", \"read\";",
           "};"
         ].join("\n"))
     }
@@ -114,7 +129,7 @@ tasks.named("test").configure {
   // this is needed for insecure plugins, remove if possible!
   systemProperty 'tests.artifact', project.name
 
-  // Setting a custom policy to manipulate com.amazonaws.sdk.ec2MetadataServiceEndpointOverride system property
+  // Setting a custom policy to manipulate aws.ec2MetadataServiceEndpoint system property
   // it is better rather disable security manager at all with `systemProperty 'tests.security.manager', 'false'`
   if (BuildParams.inFipsJvm){
     // Using the key==value format to override default JVM security settings and policy
@@ -132,30 +147,17 @@ tasks.named("check").configure {
 
 tasks.named("thirdPartyAudit").configure {
   ignoreMissingClasses(
-          // classes are missing
-          'javax.jms.Message',
-          'com.amazonaws.jmespath.JmesPathExpression',
-          'com.amazonaws.jmespath.ObjectMapperSingleton',
-          'software.amazon.ion.IonReader',
-          'software.amazon.ion.IonSystem',
-          'software.amazon.ion.IonType',
-          'software.amazon.ion.IonWriter',
-          'software.amazon.ion.Timestamp',
-          'software.amazon.ion.system.IonBinaryWriterBuilder',
-          'software.amazon.ion.system.IonSystemBuilder',
-          'software.amazon.ion.system.IonTextWriterBuilder',
-          'software.amazon.ion.system.IonWriterBuilder',
-          'javax.servlet.ServletContextEvent',
-          'javax.servlet.ServletContextListener',
-          'org.apache.avalon.framework.logger.Logger',
-          'org.apache.log.Hierarchy',
-          'org.apache.log.Logger'
+    'javax.jms.Message',
+    'javax.servlet.ServletContextEvent',
+    'javax.servlet.ServletContextListener',
+    'org.apache.avalon.framework.logger.Logger',
+    'org.apache.log.Hierarchy',
+    'org.apache.log.Logger',
+    'org.slf4j.impl.StaticLoggerBinder',
+    'org.slf4j.impl.StaticMDCBinder',
+    'org.slf4j.impl.StaticMarkerBinder',
+    'software.amazon.eventstream.HeaderValue',
+    'software.amazon.eventstream.Message',
+    'software.amazon.eventstream.MessageDecoder'
   )
-
-  if (BuildParams.runtimeJavaVersion > JavaVersion.VERSION_1_8) {
-    ignoreMissingClasses(
-            'javax.xml.bind.DatatypeConverter',
-            'javax.xml.bind.JAXBContext'
-    )
-  }
 }
diff --git a/plugins/discovery-ec2/config/discovery-ec2/log4j2.properties b/plugins/discovery-ec2/config/discovery-ec2/log4j2.properties
index 7263bbcba521c..ceb9a546b9b08 100644
--- a/plugins/discovery-ec2/config/discovery-ec2/log4j2.properties
+++ b/plugins/discovery-ec2/config/discovery-ec2/log4j2.properties
@@ -9,17 +9,17 @@
 # GitHub history for details.
 #
 
-logger.com_amazonaws.name = com.amazonaws
+logger.com_amazonaws.name = software.amazon.awssdk
 logger.com_amazonaws.level = warn
 
-logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.name = com.amazonaws.jmx.SdkMBeanRegistrySupport
+logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.name = software.amazon.awssdk.jmx.SdkMBeanRegistrySupport
 logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.level = error
 
-logger.com_amazonaws_metrics_AwsSdkMetrics.name = com.amazonaws.metrics.AwsSdkMetrics
+logger.com_amazonaws_metrics_AwsSdkMetrics.name = software.amazon.awssdk.metrics.AwsSdkMetrics
 logger.com_amazonaws_metrics_AwsSdkMetrics.level = error
 
-logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.name = com.amazonaws.auth.profile.internal.BasicProfileConfigFileLoader
+logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.name = software.amazon.awssdk.auth.profile.internal.BasicProfileConfigFileLoader
 logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.level = error
 
-logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.name = com.amazonaws.services.s3.internal.UseArnRegionResolver
+logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.name = software.amazon.awssdk.services.s3.internal.UseArnRegionResolver
 logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.level = error
diff --git a/plugins/discovery-ec2/licenses/annotations-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/annotations-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5a626eeb5725b
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/annotations-2.20.55.jar.sha1
@@ -0,0 +1 @@
+330e9d0e5f2401fffba5afe30f3740f400e8308d
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/annotations-LICENSE.txt b/plugins/discovery-ec2/licenses/annotations-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/annotations-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
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+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
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+      including but not limited to software source code, documentation
+      source, and configuration files.
+
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+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
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+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/annotations-NOTICE.txt b/plugins/discovery-ec2/licenses/annotations-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/annotations-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/apache-client-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/apache-client-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..3ee96bb6e4076
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/apache-client-2.20.55.jar.sha1
@@ -0,0 +1 @@
+5c149885667d41a306769505cfa481cfddf6f113
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/apache-client-LICENSE.txt b/plugins/discovery-ec2/licenses/apache-client-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/apache-client-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/apache-client-NOTICE.txt b/plugins/discovery-ec2/licenses/apache-client-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/apache-client-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/auth-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/auth-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..010464bdf9fd1
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/auth-2.20.55.jar.sha1
@@ -0,0 +1 @@
+e21f00a8a2096d5044f3eff176944256e01a175e
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/auth-LICENSE.txt b/plugins/discovery-ec2/licenses/auth-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/auth-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/auth-NOTICE.txt b/plugins/discovery-ec2/licenses/auth-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/auth-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/aws-core-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/aws-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4b4ee1db864a8
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+734427c2cece98a8cb90871b78d2311e4a7ef746
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/aws-core-LICENSE.txt b/plugins/discovery-ec2/licenses/aws-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/aws-core-NOTICE.txt b/plugins/discovery-ec2/licenses/aws-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/aws-java-sdk-LICENSE.txt b/plugins/discovery-ec2/licenses/aws-java-sdk-LICENSE.txt
deleted file mode 100644
index 98d1f9319f374..0000000000000
--- a/plugins/discovery-ec2/licenses/aws-java-sdk-LICENSE.txt
+++ /dev/null
@@ -1,63 +0,0 @@
-Apache License
-Version 2.0, January 2004
-
-TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-1. Definitions.
-
-"License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document.
-
-"Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License.
-
-"Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity.
-
-"You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License.
-
-"Source" form shall mean the preferred form for making modifications, including but not limited to software source code, documentation source, and configuration files.
-
-"Object" form shall mean any form resulting from mechanical transformation or translation of a Source form, including but not limited to compiled object code, generated documentation, and conversions to other media types.
-
-"Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below).
-
-"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.
-
-"Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner. For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Licensor or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as "Not a Contribution."
-
-"Contributor" shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work.
-
-2. Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.
-
-3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
-
-4. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:
-
-   1.   You must give any other recipients of the Work or Derivative Works a copy of this License; and
-   2.   You must cause any modified files to carry prominent notices stating that You changed the files; and
-   3.   You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works; and
-   4.   If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License.
-
-You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.
-
-5. Submission of Contributions. Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions.
-
-6. Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.
-
-7. Disclaimer of Warranty. Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License.
-
-8. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.
-
-9. Accepting Warranty or Additional Liability. While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability.
-
-END OF TERMS AND CONDITIONS
-
-Note: Other license terms may apply to certain, identified software files contained within or distributed with the accompanying software if such terms are included in the directory containing the accompanying software. Such other license terms will then apply in lieu of the terms of the software license above.
-
-JSON processing code subject to the JSON License from JSON.org:
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-
-The Software shall be used for Good, not Evil.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/plugins/discovery-ec2/licenses/aws-java-sdk-NOTICE.txt b/plugins/discovery-ec2/licenses/aws-java-sdk-NOTICE.txt
deleted file mode 100644
index 565bd6085c71a..0000000000000
--- a/plugins/discovery-ec2/licenses/aws-java-sdk-NOTICE.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-AWS SDK for Java
-Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
-
-This product includes software developed by
-Amazon Technologies, Inc (http://www.amazon.com/).
-
-**********************
-THIRD PARTY COMPONENTS
-**********************
-This software includes third party software subject to the following copyrights:
-- XML parsing and utility functions from JetS3t - Copyright 2006-2009 James Murty.
-- JSON parsing and utility functions from JSON.org - Copyright 2002 JSON.org.
-- PKCS#1 PEM encoded private key parsing and utility functions from oauth.googlecode.com - Copyright 1998-2010 AOL Inc.
-
-The licenses for these third party components are included in LICENSE.txt
diff --git a/plugins/discovery-ec2/licenses/aws-java-sdk-core-1.11.749.jar.sha1 b/plugins/discovery-ec2/licenses/aws-java-sdk-core-1.11.749.jar.sha1
deleted file mode 100644
index 7bc18d6d4f681..0000000000000
--- a/plugins/discovery-ec2/licenses/aws-java-sdk-core-1.11.749.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1da5c1549295cfeebc67fc1c7539785a9441755b
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/aws-java-sdk-ec2-1.11.749.jar.sha1 b/plugins/discovery-ec2/licenses/aws-java-sdk-ec2-1.11.749.jar.sha1
deleted file mode 100644
index c7c7220005fc3..0000000000000
--- a/plugins/discovery-ec2/licenses/aws-java-sdk-ec2-1.11.749.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0865e0937c6500acf62ce9c8964eac76a8718f5f
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/aws-json-protocol-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/aws-json-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..45a88305c1928
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-json-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a52731c86b974aefa5bbb1c545f407811a0163b1
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/aws-json-protocol-LICENSE.txt b/plugins/discovery-ec2/licenses/aws-json-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-json-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/aws-json-protocol-NOTICE.txt b/plugins/discovery-ec2/licenses/aws-json-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-json-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/aws-query-protocol-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/aws-query-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..ba5f43378730c
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-query-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+ac116215cc85366f0bdffee53b4c21e7a7fe03ef
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/aws-query-protocol-LICENSE.txt b/plugins/discovery-ec2/licenses/aws-query-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-query-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/aws-query-protocol-NOTICE.txt b/plugins/discovery-ec2/licenses/aws-query-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/aws-query-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/commons-codec-1.13.jar.sha1 b/plugins/discovery-ec2/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/discovery-ec2/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/commons-codec-1.15.jar.sha1 b/plugins/discovery-ec2/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/discovery-ec2/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index c8756c438320f..0000000000000
--- a/plugins/discovery-ec2/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
diff --git a/plugins/discovery-ec2/licenses/commons-logging-1.2.jar.sha1 b/plugins/discovery-ec2/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/ec2-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/ec2-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..f123343bfe27e
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/ec2-2.20.55.jar.sha1
@@ -0,0 +1 @@
+c095e527442835130b18387da6b1d01f365a6dbf
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/ec2-LICENSE.txt b/plugins/discovery-ec2/licenses/ec2-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/ec2-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/ec2-NOTICE.txt b/plugins/discovery-ec2/licenses/ec2-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/ec2-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/endpoints-spi-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/endpoints-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5bc0e31166c77
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/endpoints-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+085f82038ee86a7d6cd568fe7edd842978d92de3
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/endpoints-spi-LICENSE.txt b/plugins/discovery-ec2/licenses/endpoints-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/endpoints-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/endpoints-spi-NOTICE.txt b/plugins/discovery-ec2/licenses/endpoints-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/endpoints-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/http-client-spi-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/http-client-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..523cf43dcb2e9
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/http-client-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+34f9b10c1a46038a0ceebdd750ba3a413a862ceb
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/http-client-spi-LICENSE.txt b/plugins/discovery-ec2/licenses/http-client-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/http-client-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/http-client-spi-NOTICE.txt b/plugins/discovery-ec2/licenses/http-client-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/http-client-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/httpclient-4.5.13.jar.sha1 b/plugins/discovery-ec2/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/plugins/discovery-ec2/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/httpclient-4.5.14.jar.sha1 b/plugins/discovery-ec2/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/httpcore-4.4.12.jar.sha1 b/plugins/discovery-ec2/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/plugins/discovery-ec2/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/httpcore-4.4.16.jar.sha1 b/plugins/discovery-ec2/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/jackson-annotations-2.13.2.jar.sha1 b/plugins/discovery-ec2/licenses/jackson-annotations-2.13.2.jar.sha1
deleted file mode 100644
index ecd3fb49d5b12..0000000000000
--- a/plugins/discovery-ec2/licenses/jackson-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ec18851f1976d5b810ae1a5fcc32520d2d38f77a
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/jackson-annotations-2.15.2.jar.sha1 b/plugins/discovery-ec2/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/jackson-databind-2.13.2.jar.sha1 b/plugins/discovery-ec2/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/plugins/discovery-ec2/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/jackson-databind-2.15.2.jar.sha1 b/plugins/discovery-ec2/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/json-utils-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/json-utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..a19b00e62f8b5
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/json-utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+cd6710900e3190eac4c4496ae529ce08680dd320
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/json-utils-LICENSE.txt b/plugins/discovery-ec2/licenses/json-utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/json-utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/json-utils-NOTICE.txt b/plugins/discovery-ec2/licenses/json-utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/json-utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/log4j-1.2-api-2.17.1.jar.sha1 b/plugins/discovery-ec2/licenses/log4j-1.2-api-2.17.1.jar.sha1
deleted file mode 100644
index 23aa5c60bd596..0000000000000
--- a/plugins/discovery-ec2/licenses/log4j-1.2-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-db3a7e7f07e878b92ac4a8f1100bee8325d5713a
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/discovery-ec2/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/metrics-spi-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/metrics-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..db6701d87892a
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/metrics-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8a0eae705b27465516f3b09cc9918e40963d534d
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/metrics-spi-LICENSE.txt b/plugins/discovery-ec2/licenses/metrics-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/metrics-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/metrics-spi-NOTICE.txt b/plugins/discovery-ec2/licenses/metrics-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/metrics-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/profiles-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/profiles-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..b7104cf0939e6
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/profiles-2.20.55.jar.sha1
@@ -0,0 +1 @@
+959aad08b2f24057bf286c761b49e3af31a0a623
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/profiles-LICENSE.txt b/plugins/discovery-ec2/licenses/profiles-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/profiles-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/profiles-NOTICE.txt b/plugins/discovery-ec2/licenses/profiles-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/profiles-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/protocol-core-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/protocol-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4dee45f4d9dd3
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/protocol-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+0935e3ab32962a890f1d13bf39ba2167d9d692f9
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/protocol-core-LICENSE.txt b/plugins/discovery-ec2/licenses/protocol-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/protocol-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/protocol-core-NOTICE.txt b/plugins/discovery-ec2/licenses/protocol-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/protocol-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/reactive-streams-1.0.4.jar.sha1 b/plugins/discovery-ec2/licenses/reactive-streams-1.0.4.jar.sha1
new file mode 100644
index 0000000000000..45a80e3f7e361
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/reactive-streams-1.0.4.jar.sha1
@@ -0,0 +1 @@
+3864a1320d97d7b045f729a326e1e077661f31b7
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/reactive-streams-LICENSE.txt b/plugins/discovery-ec2/licenses/reactive-streams-LICENSE.txt
new file mode 100644
index 0000000000000..1e3c7e7c77495
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/reactive-streams-LICENSE.txt
@@ -0,0 +1,21 @@
+MIT No Attribution
+
+Copyright 2014 Reactive Streams
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/grpc-context-NOTICE.txt b/plugins/discovery-ec2/licenses/reactive-streams-NOTICE.txt
similarity index 100%
rename from plugins/repository-gcs/licenses/grpc-context-NOTICE.txt
rename to plugins/discovery-ec2/licenses/reactive-streams-NOTICE.txt
diff --git a/plugins/discovery-ec2/licenses/regions-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/regions-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..993fc2f97de62
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/regions-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a117c19b4a30e902f4f1cc4bef6b5c10cc9aef31
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/regions-LICENSE.txt b/plugins/discovery-ec2/licenses/regions-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/regions-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/regions-NOTICE.txt b/plugins/discovery-ec2/licenses/regions-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/regions-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/sdk-core-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/sdk-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5f12be9c08c5b
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/sdk-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8f2347feaf2575560ca89a2caa8d0243dbeb17a9
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/sdk-core-LICENSE.txt b/plugins/discovery-ec2/licenses/sdk-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/sdk-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/sdk-core-NOTICE.txt b/plugins/discovery-ec2/licenses/sdk-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/sdk-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/discovery-ec2/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/slf4j-api-LICENSE.txt b/plugins/discovery-ec2/licenses/slf4j-api-LICENSE.txt
new file mode 100644
index 0000000000000..2be7689435062
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/slf4j-api-LICENSE.txt
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2022 QOS.ch
+All rights reserved.
+
+Permission is hereby granted, free  of charge, to any person obtaining
+a  copy  of this  software  and  associated  documentation files  (the
+"Software"), to  deal in  the Software without  restriction, including
+without limitation  the rights to  use, copy, modify,  merge, publish,
+distribute,  sublicense, and/or sell  copies of  the Software,  and to
+permit persons to whom the Software  is furnished to do so, subject to
+the following conditions:
+
+The  above  copyright  notice  and  this permission  notice  shall  be
+included in all copies or substantial portions of the Software.
+
+THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
+EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
+MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/slf4j-api-NOTICE.txt b/plugins/discovery-ec2/licenses/slf4j-api-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/discovery-ec2/licenses/third-party-jackson-core-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/third-party-jackson-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..e7eebbb98f1fe
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/third-party-jackson-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+956912f26056fc7d46b2db566362fe5f7a8c0e14
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/third-party-jackson-core-LICENSE.txt b/plugins/discovery-ec2/licenses/third-party-jackson-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/third-party-jackson-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/third-party-jackson-core-NOTICE.txt b/plugins/discovery-ec2/licenses/third-party-jackson-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/third-party-jackson-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/licenses/utils-2.20.55.jar.sha1 b/plugins/discovery-ec2/licenses/utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..fc4cde604e33c
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+d3e1bbbc19795eadbeb4dd963a94647576644097
\ No newline at end of file
diff --git a/plugins/discovery-ec2/licenses/utils-LICENSE.txt b/plugins/discovery-ec2/licenses/utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/discovery-ec2/licenses/utils-NOTICE.txt b/plugins/discovery-ec2/licenses/utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/discovery-ec2/licenses/utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/discovery-ec2/qa/amazon-ec2/build.gradle b/plugins/discovery-ec2/qa/amazon-ec2/build.gradle
index d63015f25b408..a844576d67ece 100644
--- a/plugins/discovery-ec2/qa/amazon-ec2/build.gradle
+++ b/plugins/discovery-ec2/qa/amazon-ec2/build.gradle
@@ -67,7 +67,7 @@ yamlRestTest.enabled = false
  * Test using various credential providers (see also https://docs.aws.amazon.com/sdk-for-java/v2/developer-guide/credentials.html):
  * - Elasticsearch Keystore (secure settings discovery.ec2.access_key and discovery.ec2.secret_key)
  * - Java system properties (aws.accessKeyId and aws.secretAccessKey)
- * - Environment variables (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY)
+ * - Environment variables (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_REGION)
  * - ECS container credentials (loaded from ECS if the environment variable AWS_CONTAINER_CREDENTIALS_RELATIVE_URI is set)
  * - Instance profile credentials (delivered through the EC2 metadata service)
  *
@@ -100,8 +100,9 @@ yamlRestTest.enabled = false
     setting 'discovery.seed_providers', 'ec2'
     setting 'network.host', '_ec2_'
     setting 'discovery.ec2.endpoint', { "http://${-> fixture.addressAndPort}" }, IGNORE_VALUE
+    setting 'discovery.ec2.region', 'us-east-1'
 
-    systemProperty "com.amazonaws.sdk.ec2MetadataServiceEndpointOverride", { "http://${-> fixture.addressAndPort}" }, IGNORE_VALUE
+    systemProperty "aws.ec2MetadataServiceEndpoint", { "http://${-> fixture.addressAndPort}" }, IGNORE_VALUE
   }
 }
 
@@ -115,12 +116,14 @@ testClusters.yamlRestTestKeyStore {
 testClusters.yamlRestTestEnvVariables {
   environment 'AWS_ACCESS_KEY_ID', 'ec2_integration_test_access_key'
   environment 'AWS_SECRET_ACCESS_KEY', 'ec2_integration_test_secret_key'
+  environment 'AWS_REGION', 'ec2_integration_test_region'
 }
 
 // Extra config for SystemProperties
 testClusters.yamlRestTestSystemProperties {
   systemProperty 'aws.accessKeyId', 'ec2_integration_test_access_key'
-  systemProperty 'aws.secretKey', 'ec2_integration_test_secret_key'
+  systemProperty 'aws.secretAccessKey', 'ec2_integration_test_secret_key'
+  systemProperty 'aws.region', 'ec2_integration_test_region'
 }
 
 // Extra config for ContainerCredentials
diff --git a/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2DiscoveryClientYamlTestSuiteIT.java b/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2DiscoveryClientYamlTestSuiteIT.java
index a0f4984751a7b..6e86148f208bd 100644
--- a/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2DiscoveryClientYamlTestSuiteIT.java
+++ b/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2DiscoveryClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2Fixture.java b/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2Fixture.java
index 7ff6a0f0ec16a..8dc9db69b674f 100644
--- a/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2Fixture.java
+++ b/plugins/discovery-ec2/qa/amazon-ec2/src/yamlRestTest/java/org/opensearch/discovery/ec2/AmazonEC2Fixture.java
@@ -31,21 +31,22 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.util.DateUtils;
+import software.amazon.awssdk.utils.DateUtils;
+
 import org.apache.http.NameValuePair;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.client.methods.HttpPut;
 import org.apache.http.client.utils.URLEncodedUtils;
-
 import org.opensearch.common.Booleans;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.fixture.AbstractHttpFixture;
 
 import javax.xml.XMLConstants;
 import javax.xml.stream.XMLOutputFactory;
 import javax.xml.stream.XMLStreamWriter;
+
 import java.io.IOException;
 import java.io.StringWriter;
 import java.nio.file.Files;
@@ -138,7 +139,7 @@ protected Response handle(final Request request) throws IOException {
                 + "ec2_integration_test_access_key"
                 + "\","
                 + "\"Expiration\": \""
-                + DateUtils.formatISO8601Date(expiration)
+                + DateUtils.formatIso8601Date(expiration.toInstant())
                 + "\","
                 + "\"RoleArn\": \""
                 + "test"
diff --git a/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/AbstractAwsTestCase.java b/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/AbstractAwsTestCase.java
index 1e7422ea0ac02..9529d1e67ea09 100644
--- a/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/AbstractAwsTestCase.java
+++ b/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/AbstractAwsTestCase.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.discovery.ec2;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
diff --git a/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java b/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java
index 453ea2b3268a8..659bec0c6e89e 100644
--- a/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java
+++ b/plugins/discovery-ec2/src/internalClusterTest/java/org/opensearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java
@@ -48,7 +48,7 @@
  */
 @ClusterScope(scope = Scope.TEST, numDataNodes = 0, numClientNodes = 0)
 public class Ec2DiscoveryUpdateSettingsTests extends AbstractAwsTestCase {
-    public void testMinimumMasterNodesStart() {
+    public void testMinimumClusterManagerNodesStart() {
         Settings nodeSettings = Settings.builder().put(DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING.getKey(), "ec2").build();
         internalCluster().startNode(nodeSettings);
 
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2ClientReference.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2ClientReference.java
new file mode 100644
index 0000000000000..1c5ffbfb38ec3
--- /dev/null
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2ClientReference.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery.ec2;
+
+import software.amazon.awssdk.services.ec2.Ec2Client;
+
+import org.opensearch.common.concurrent.RefCountedReleasable;
+
+/**
+ * Handles the shutdown of the wrapped {@link Ec2Client} using reference
+ * counting.
+ */
+public class AmazonEc2ClientReference extends RefCountedReleasable<Ec2Client> {
+
+    AmazonEc2ClientReference(Ec2Client client) {
+        super("AWS_EC2_CLIENT", client, client::close);
+    }
+}
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2Reference.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2Reference.java
deleted file mode 100644
index 2686c376213f3..0000000000000
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2Reference.java
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.discovery.ec2;
-
-import com.amazonaws.services.ec2.AmazonEC2;
-import org.opensearch.common.concurrent.RefCountedReleasable;
-
-/**
- * Handles the shutdown of the wrapped {@link AmazonEC2} using reference
- * counting.
- */
-public class AmazonEc2Reference extends RefCountedReleasable<AmazonEC2> {
-
-    AmazonEc2Reference(AmazonEC2 client) {
-        super("AWS_EC2_CLIENT", client, client::shutdown);
-    }
-}
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2SeedHostsProvider.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2SeedHostsProvider.java
index f26ecfab501f8..fb46b82065fd1 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2SeedHostsProvider.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2SeedHostsProvider.java
@@ -32,23 +32,23 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.services.ec2.model.DescribeInstancesRequest;
-import com.amazonaws.services.ec2.model.DescribeInstancesResult;
-import com.amazonaws.services.ec2.model.Filter;
-import com.amazonaws.services.ec2.model.GroupIdentifier;
-import com.amazonaws.services.ec2.model.Instance;
-import com.amazonaws.services.ec2.model.Reservation;
-import com.amazonaws.services.ec2.model.Tag;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.services.ec2.model.DescribeInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.DescribeInstancesResponse;
+import software.amazon.awssdk.services.ec2.model.Filter;
+import software.amazon.awssdk.services.ec2.model.GroupIdentifier;
+import software.amazon.awssdk.services.ec2.model.Instance;
+import software.amazon.awssdk.services.ec2.model.Reservation;
+import software.amazon.awssdk.services.ec2.model.Tag;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.SingleObjectCache;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.transport.TransportService;
 
@@ -85,6 +85,8 @@ class AwsEc2SeedHostsProvider implements SeedHostsProvider {
 
     private final TransportAddressesCache dynamicHosts;
 
+    private final Set<String> instanceStates;
+
     AwsEc2SeedHostsProvider(Settings settings, TransportService transportService, AwsEc2Service awsEc2Service) {
         this.transportService = transportService;
         this.awsEc2Service = awsEc2Service;
@@ -101,6 +103,10 @@ class AwsEc2SeedHostsProvider implements SeedHostsProvider {
         this.availabilityZones = new HashSet<>();
         availabilityZones.addAll(AwsEc2Service.AVAILABILITY_ZONES_SETTING.get(settings));
 
+        this.instanceStates = new HashSet<>();
+        instanceStates.add("running");
+        instanceStates.add("pending");
+
         if (logger.isDebugEnabled()) {
             logger.debug(
                 "using host_type [{}], tags [{}], groups [{}] with any_group [{}], availability_zones [{}]",
@@ -119,41 +125,47 @@ public List<TransportAddress> getSeedAddresses(HostsResolver hostsResolver) {
     }
 
     protected List<TransportAddress> fetchDynamicNodes() {
+        logger.info(
+            "fetching nodes from IMDS (instance-states={}, availability-zones={}, tags={}) ...",
+            instanceStates,
+            availabilityZones,
+            tags
+        );
 
         final List<TransportAddress> dynamicHosts = new ArrayList<>();
 
-        final DescribeInstancesResult descInstances;
-        try (AmazonEc2Reference clientReference = awsEc2Service.client()) {
+        final DescribeInstancesResponse descInstances;
+        try (AmazonEc2ClientReference clientReference = awsEc2Service.client()) {
             // Query EC2 API based on AZ, instance state, and tag.
 
             // NOTE: we don't filter by security group during the describe instances request for two reasons:
             // 1. differences in VPCs require different parameters during query (ID vs Name)
             // 2. We want to use two different strategies: (all security groups vs. any security groups)
-            descInstances = SocketAccess.doPrivileged(() -> clientReference.get().describeInstances(buildDescribeInstancesRequest()));
-        } catch (final AmazonClientException e) {
-            logger.info("Exception while retrieving instance list from AWS API: {}", e.getMessage());
-            logger.debug("Full exception:", e);
+            DescribeInstancesRequest instancesRequest = buildDescribeInstancesRequest();
+            descInstances = SocketAccess.doPrivileged(() -> clientReference.get().describeInstances(instancesRequest));
+        } catch (final SdkException e) {
+            logger.warn("error retrieving instance list from IMDS", e);
             return dynamicHosts;
         }
 
-        logger.trace("finding seed nodes...");
-        for (final Reservation reservation : descInstances.getReservations()) {
-            for (final Instance instance : reservation.getInstances()) {
+        logger.trace("finding seed nodes ...");
+        for (final Reservation reservation : descInstances.reservations()) {
+            for (final Instance instance : reservation.instances()) {
                 // lets see if we can filter based on groups
                 if (!groups.isEmpty()) {
-                    final List<GroupIdentifier> instanceSecurityGroups = instance.getSecurityGroups();
+                    final List<GroupIdentifier> instanceSecurityGroups = instance.securityGroups();
                     final List<String> securityGroupNames = new ArrayList<>(instanceSecurityGroups.size());
                     final List<String> securityGroupIds = new ArrayList<>(instanceSecurityGroups.size());
                     for (final GroupIdentifier sg : instanceSecurityGroups) {
-                        securityGroupNames.add(sg.getGroupName());
-                        securityGroupIds.add(sg.getGroupId());
+                        securityGroupNames.add(sg.groupName());
+                        securityGroupIds.add(sg.groupId());
                     }
                     if (bindAnyGroup) {
                         // We check if we can find at least one group name or one group id in groups.
                         if (disjoint(securityGroupNames, groups) && disjoint(securityGroupIds, groups)) {
                             logger.trace(
                                 "filtering out instance {} based on groups {}, not part of {}",
-                                instance.getInstanceId(),
+                                instance.instanceId(),
                                 instanceSecurityGroups,
                                 groups
                             );
@@ -165,7 +177,7 @@ protected List<TransportAddress> fetchDynamicNodes() {
                         if (!(securityGroupNames.containsAll(groups) || securityGroupIds.containsAll(groups))) {
                             logger.trace(
                                 "filtering out instance {} based on groups {}, does not include all of {}",
-                                instance.getInstanceId(),
+                                instance.instanceId(),
                                 instanceSecurityGroups,
                                 groups
                             );
@@ -177,21 +189,21 @@ protected List<TransportAddress> fetchDynamicNodes() {
 
                 String address = null;
                 if (hostType.equals(PRIVATE_DNS)) {
-                    address = instance.getPrivateDnsName();
+                    address = instance.privateDnsName();
                 } else if (hostType.equals(PRIVATE_IP)) {
-                    address = instance.getPrivateIpAddress();
+                    address = instance.privateIpAddress();
                 } else if (hostType.equals(PUBLIC_DNS)) {
-                    address = instance.getPublicDnsName();
+                    address = instance.publicDnsName();
                 } else if (hostType.equals(PUBLIC_IP)) {
-                    address = instance.getPublicIpAddress();
+                    address = instance.publicIpAddress();
                 } else if (hostType.startsWith(TAG_PREFIX)) {
                     // Reading the node host from its metadata
                     final String tagName = hostType.substring(TAG_PREFIX.length());
                     logger.debug("reading hostname from [{}] instance tag", tagName);
-                    final List<Tag> tags = instance.getTags();
+                    final List<Tag> tags = instance.tags();
                     for (final Tag tag : tags) {
-                        if (tag.getKey().equals(tagName)) {
-                            address = tag.getValue();
+                        if (tag.key().equals(tagName)) {
+                            address = tag.value();
                             logger.debug("using [{}] as the instance address", address);
                         }
                     }
@@ -202,7 +214,7 @@ protected List<TransportAddress> fetchDynamicNodes() {
                     try {
                         final TransportAddress[] addresses = transportService.addressesFromString(address);
                         for (int i = 0; i < addresses.length; i++) {
-                            logger.trace("adding {}, address {}, transport_address {}", instance.getInstanceId(), address, addresses[i]);
+                            logger.debug("adding {}, address {}, transport_address {}", instance.instanceId(), address, addresses[i]);
                             dynamicHosts.add(addresses[i]);
                         }
                     } catch (final Exception e) {
@@ -210,39 +222,38 @@ protected List<TransportAddress> fetchDynamicNodes() {
                         logger.warn(
                             (Supplier<?>) () -> new ParameterizedMessage(
                                 "failed to add {}, address {}",
-                                instance.getInstanceId(),
+                                instance.instanceId(),
                                 finalAddress
                             ),
                             e
                         );
                     }
                 } else {
-                    logger.trace("not adding {}, address is null, host_type {}", instance.getInstanceId(), hostType);
+                    logger.warn("not adding {}, address is null, host_type {}", instance.instanceId(), hostType);
                 }
             }
         }
 
-        logger.debug("using dynamic transport addresses {}", dynamicHosts);
+        logger.info("using dynamic transport addresses {}", dynamicHosts);
 
         return dynamicHosts;
     }
 
     private DescribeInstancesRequest buildDescribeInstancesRequest() {
-        final DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest().withFilters(
-            new Filter("instance-state-name").withValues("running", "pending")
-        );
+        ArrayList<Filter> filters = new ArrayList<Filter>();
+        filters.add(Filter.builder().name("instance-state-name").values(instanceStates).build());
 
         for (final Map.Entry<String, List<String>> tagFilter : tags.entrySet()) {
             // for a given tag key, OR relationship for multiple different values
-            describeInstancesRequest.withFilters(new Filter("tag:" + tagFilter.getKey()).withValues(tagFilter.getValue()));
+            filters.add(Filter.builder().name("tag:" + tagFilter.getKey()).values(tagFilter.getValue()).build());
         }
 
         if (!availabilityZones.isEmpty()) {
             // OR relationship amongst multiple values of the availability-zone filter
-            describeInstancesRequest.withFilters(new Filter("availability-zone").withValues(availabilityZones));
+            filters.add(Filter.builder().name("availability-zone").values(availabilityZones).build());
         }
 
-        return describeInstancesRequest;
+        return DescribeInstancesRequest.builder().filters(filters).build();
     }
 
     private final class TransportAddressesCache extends SingleObjectCache<List<TransportAddress>> {
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2Service.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2Service.java
index c3ed4340467bd..58d0cdb5e87aa 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2Service.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2Service.java
@@ -43,6 +43,7 @@
 import java.util.function.Function;
 
 interface AwsEc2Service extends Closeable {
+
     Setting<Boolean> AUTO_ATTRIBUTE_SETTING = Setting.boolSetting("cloud.node.auto_attributes", false, Property.NodeScope);
 
     class HostType {
@@ -115,7 +116,7 @@ class HostType {
      * settings. Returns an {@code AmazonEc2Reference} wrapper which should be
      * released as soon as it is not required anymore.
      */
-    AmazonEc2Reference client();
+    AmazonEc2ClientReference client();
 
     /**
      * Updates the settings for building the client and releases the cached one.
@@ -125,5 +126,4 @@ class HostType {
      * @param clientSettings the new refreshed settings
      */
     void refreshAndClearCache(Ec2ClientSettings clientSettings);
-
 }
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2ServiceImpl.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2ServiceImpl.java
index 7566a7094e635..51f0ad9526e55 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2ServiceImpl.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2ServiceImpl.java
@@ -32,82 +32,140 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
-import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
-import com.amazonaws.client.builder.AwsClientBuilder;
-import com.amazonaws.http.IdleConnectionReaper;
-import com.amazonaws.services.ec2.AmazonEC2;
-import com.amazonaws.services.ec2.AmazonEC2ClientBuilder;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.http.apache.ApacheHttpClient;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.ec2.Ec2Client;
+import software.amazon.awssdk.services.ec2.Ec2ClientBuilder;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.util.LazyInitializable;
+import org.opensearch.core.common.Strings;
 
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.time.Duration;
 import java.util.concurrent.atomic.AtomicReference;
 
 class AwsEc2ServiceImpl implements AwsEc2Service {
-
     private static final Logger logger = LogManager.getLogger(AwsEc2ServiceImpl.class);
 
-    private final AtomicReference<LazyInitializable<AmazonEc2Reference, OpenSearchException>> lazyClientReference = new AtomicReference<>();
-
-    private AmazonEC2 buildClient(Ec2ClientSettings clientSettings) {
-        final AWSCredentialsProvider credentials = buildCredentials(logger, clientSettings);
-        final ClientConfiguration configuration = buildConfiguration(logger, clientSettings);
-        return buildClient(credentials, configuration, clientSettings.endpoint);
+    private final AtomicReference<LazyInitializable<AmazonEc2ClientReference, OpenSearchException>> lazyClientReference =
+        new AtomicReference<>();
+
+    private Ec2Client buildClient(Ec2ClientSettings clientSettings) {
+        SocketAccess.doPrivilegedVoid(AwsEc2ServiceImpl::setDefaultAwsProfilePath);
+        final AwsCredentialsProvider awsCredentialsProvider = buildCredentials(logger, clientSettings);
+        final ClientOverrideConfiguration overrideConfiguration = buildOverrideConfiguration(logger, clientSettings);
+        final ProxyConfiguration proxyConfiguration = SocketAccess.doPrivileged(() -> buildProxyConfiguration(logger, clientSettings));
+        return buildClient(
+            awsCredentialsProvider,
+            proxyConfiguration,
+            overrideConfiguration,
+            clientSettings.endpoint,
+            clientSettings.region,
+            clientSettings.readTimeoutMillis
+        );
     }
 
     // proxy for testing
-    AmazonEC2 buildClient(AWSCredentialsProvider credentials, ClientConfiguration configuration, String endpoint) {
-        final AmazonEC2ClientBuilder builder = AmazonEC2ClientBuilder.standard()
-            .withCredentials(credentials)
-            .withClientConfiguration(configuration);
+    protected Ec2Client buildClient(
+        AwsCredentialsProvider awsCredentialsProvider,
+        ProxyConfiguration proxyConfiguration,
+        ClientOverrideConfiguration overrideConfiguration,
+        String endpoint,
+        String region,
+        long readTimeoutMillis
+    ) {
+        ApacheHttpClient.Builder clientBuilder = ApacheHttpClient.builder()
+            .proxyConfiguration(proxyConfiguration)
+            .socketTimeout(Duration.ofMillis(readTimeoutMillis));
+
+        Ec2ClientBuilder builder = Ec2Client.builder()
+            .overrideConfiguration(overrideConfiguration)
+            .httpClientBuilder(clientBuilder)
+            .credentialsProvider(awsCredentialsProvider);
+
         if (Strings.hasText(endpoint)) {
             logger.debug("using explicit ec2 endpoint [{}]", endpoint);
-            builder.withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint, null));
+            builder.endpointOverride(URI.create(endpoint));
         }
+
+        if (Strings.hasText(region)) {
+            logger.debug("using explicit ec2 region [{}]", region);
+            builder.region(Region.of(region));
+        }
+
         return SocketAccess.doPrivileged(builder::build);
     }
 
-    // pkg private for tests
-    static ClientConfiguration buildConfiguration(Logger logger, Ec2ClientSettings clientSettings) {
-        final ClientConfiguration clientConfiguration = new ClientConfiguration();
-        // the response metadata cache is only there for diagnostics purposes,
-        // but can force objects from every response to the old generation.
-        clientConfiguration.setResponseMetadataCacheSize(0);
-        clientConfiguration.setProtocol(clientSettings.protocol);
+    static ProxyConfiguration buildProxyConfiguration(Logger logger, Ec2ClientSettings clientSettings) {
         if (Strings.hasText(clientSettings.proxyHost)) {
-            // TODO: remove this leniency, these settings should exist together and be validated
-            clientConfiguration.setProxyHost(clientSettings.proxyHost);
-            clientConfiguration.setProxyPort(clientSettings.proxyPort);
-            clientConfiguration.setProxyUsername(clientSettings.proxyUsername);
-            clientConfiguration.setProxyPassword(clientSettings.proxyPassword);
+            try {
+                // TODO: remove this leniency, these settings should exist together and be validated
+                return ProxyConfiguration.builder()
+                    .endpoint(
+                        new URI(
+                            clientSettings.protocol.toString(),
+                            null,
+                            clientSettings.proxyHost,
+                            clientSettings.proxyPort,
+                            null,
+                            null,
+                            null
+                        )
+                    )
+                    .username(clientSettings.proxyUsername)
+                    .password(clientSettings.proxyPassword)
+                    .build();
+            } catch (URISyntaxException e) {
+                throw SdkException.create("Invalid proxy URL", e);
+            }
+        } else {
+            return ProxyConfiguration.builder().build();
         }
-        // Increase the number of retries in case of 5xx API responses
-        clientConfiguration.setMaxErrorRetry(10);
-        clientConfiguration.setSocketTimeout(clientSettings.readTimeoutMillis);
-        return clientConfiguration;
+    }
+
+    static ClientOverrideConfiguration buildOverrideConfiguration(Logger logger, Ec2ClientSettings clientSettings) {
+        return ClientOverrideConfiguration.builder().retryPolicy(buildRetryPolicy(logger, clientSettings)).build();
     }
 
     // pkg private for tests
-    static AWSCredentialsProvider buildCredentials(Logger logger, Ec2ClientSettings clientSettings) {
-        final AWSCredentials credentials = clientSettings.credentials;
+    static RetryPolicy buildRetryPolicy(Logger logger, Ec2ClientSettings clientSettings) {
+        // Increase the number of retries in case of 5xx API responses.
+        // Note that AWS SDK v2 introduced a concept of TokenBucketRetryCondition, which effectively limits retries for
+        // APIs that have been failing continuously. It allocates tokens (default is 500), which means that once 500
+        // retries fail for any API on a bucket, new retries will only be allowed once some retries are rejected.
+        // https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/core/retry/conditions/TokenBucketRetryCondition.html
+        RetryPolicy.Builder retryPolicy = RetryPolicy.builder().numRetries(10);
+        return retryPolicy.build();
+    }
+
+    static AwsCredentialsProvider buildCredentials(Logger logger, Ec2ClientSettings clientSettings) {
+        final AwsCredentials credentials = clientSettings.credentials;
         if (credentials == null) {
-            logger.debug("Using default provider chain");
-            return DefaultAWSCredentialsProviderChain.getInstance();
+            logger.debug("Using default credentials provider");
+            return DefaultCredentialsProvider.create();
         } else {
             logger.debug("Using basic key/secret credentials");
-            return new AWSStaticCredentialsProvider(credentials);
+            return StaticCredentialsProvider.create(credentials);
         }
     }
 
     @Override
-    public AmazonEc2Reference client() {
-        final LazyInitializable<AmazonEc2Reference, OpenSearchException> clientReference = this.lazyClientReference.get();
+    public AmazonEc2ClientReference client() {
+        final LazyInitializable<AmazonEc2ClientReference, OpenSearchException> clientReference = this.lazyClientReference.get();
         if (clientReference == null) {
             throw new IllegalStateException("Missing ec2 client configs");
         }
@@ -121,12 +179,12 @@ public AmazonEc2Reference client() {
      */
     @Override
     public void refreshAndClearCache(Ec2ClientSettings clientSettings) {
-        final LazyInitializable<AmazonEc2Reference, OpenSearchException> newClient = new LazyInitializable<>(
-            () -> new AmazonEc2Reference(buildClient(clientSettings)),
+        final LazyInitializable<AmazonEc2ClientReference, OpenSearchException> newClient = new LazyInitializable<>(
+            () -> new AmazonEc2ClientReference(buildClient(clientSettings)),
             clientReference -> clientReference.incRef(),
             clientReference -> clientReference.decRef()
         );
-        final LazyInitializable<AmazonEc2Reference, OpenSearchException> oldClient = this.lazyClientReference.getAndSet(newClient);
+        final LazyInitializable<AmazonEc2ClientReference, OpenSearchException> oldClient = this.lazyClientReference.getAndSet(newClient);
         if (oldClient != null) {
             oldClient.reset();
         }
@@ -134,13 +192,22 @@ public void refreshAndClearCache(Ec2ClientSettings clientSettings) {
 
     @Override
     public void close() {
-        final LazyInitializable<AmazonEc2Reference, OpenSearchException> clientReference = this.lazyClientReference.getAndSet(null);
+        final LazyInitializable<AmazonEc2ClientReference, OpenSearchException> clientReference = this.lazyClientReference.getAndSet(null);
         if (clientReference != null) {
             clientReference.reset();
         }
-        // shutdown IdleConnectionReaper background thread
-        // it will be restarted on new client usage
-        IdleConnectionReaper.shutdown();
     }
 
+    // By default, AWS v2 SDK loads a default profile from $USER_HOME, which is restricted. Use the OpenSearch configuration path instead.
+    @SuppressForbidden(reason = "Prevent AWS SDK v2 from using ~/.aws/config and ~/.aws/credentials.")
+    static void setDefaultAwsProfilePath() {
+        if (ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.getStringValue().isEmpty()) {
+            logger.info("setting aws.sharedCredentialsFile={}", System.getProperty("opensearch.path.conf"));
+            System.setProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+        if (ProfileFileSystemSetting.AWS_CONFIG_FILE.getStringValue().isEmpty()) {
+            logger.info("setting aws.sharedCredentialsFile={}", System.getProperty("opensearch.path.conf"));
+            System.setProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+    }
 }
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2ClientSettings.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2ClientSettings.java
index 406be47503be2..8c010bbcdec3a 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2ClientSettings.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2ClientSettings.java
@@ -32,21 +32,21 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.Protocol;
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.BasicAWSCredentials;
-import com.amazonaws.auth.BasicSessionCredentials;
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.core.Protocol;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.settings.SecureString;
 
 import java.util.Locale;
 
@@ -78,7 +78,16 @@ final class Ec2ClientSettings {
         Property.NodeScope
     );
 
-    /** The protocol to use to connect to to ec2. */
+    /** An override for the scoping region for authentication. */
+    static final Setting<String> REGION_SETTING = new Setting<>(
+        "discovery.ec2.region",
+        "",
+        s -> s.toLowerCase(Locale.ROOT),
+        Property.NodeScope
+    );
+
+    /** The protocol to use to connect to ec2. AWS SDKv2 only supports HTTPs, deprecated in 3.0. */
+    @Deprecated
     static final Setting<Protocol> PROTOCOL_SETTING = new Setting<>(
         "discovery.ec2.protocol",
         "https",
@@ -95,7 +104,7 @@ final class Ec2ClientSettings {
     /** The socket timeout for connecting to s3. */
     static final Setting<TimeValue> READ_TIMEOUT_SETTING = Setting.timeSetting(
         "discovery.ec2.read_timeout",
-        TimeValue.timeValueMillis(ClientConfiguration.DEFAULT_SOCKET_TIMEOUT),
+        TimeValue.timeValueMillis(50_000),
         Property.NodeScope
     );
 
@@ -104,7 +113,7 @@ final class Ec2ClientSettings {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(Ec2ClientSettings.class);
 
     /** Credentials to authenticate with ec2. */
-    final AWSCredentials credentials;
+    final AwsCredentials credentials;
 
     /**
      * The ec2 endpoint the client should talk to, or empty string to use the
@@ -112,6 +121,11 @@ final class Ec2ClientSettings {
      */
     final String endpoint;
 
+    /**
+     * The ec2 signing region.
+     */
+    final String region;
+
     /** The protocol to use to talk to ec2. Defaults to https. */
     final Protocol protocol;
 
@@ -134,8 +148,9 @@ final class Ec2ClientSettings {
     final int readTimeoutMillis;
 
     protected Ec2ClientSettings(
-        AWSCredentials credentials,
+        AwsCredentials credentials,
         String endpoint,
+        String region,
         Protocol protocol,
         String proxyHost,
         int proxyPort,
@@ -145,6 +160,7 @@ protected Ec2ClientSettings(
     ) {
         this.credentials = credentials;
         this.endpoint = endpoint;
+        this.region = region;
         this.protocol = protocol;
         this.proxyHost = proxyHost;
         this.proxyPort = proxyPort;
@@ -153,7 +169,7 @@ protected Ec2ClientSettings(
         this.readTimeoutMillis = readTimeoutMillis;
     }
 
-    static AWSCredentials loadCredentials(Settings settings) {
+    static AwsCredentials loadCredentials(Settings settings) {
         try (
             SecureString key = ACCESS_KEY_SETTING.get(settings);
             SecureString secret = SECRET_KEY_SETTING.get(settings);
@@ -173,39 +189,37 @@ static AWSCredentials loadCredentials(Settings settings) {
                 return null;
             } else {
                 if (key.length() == 0) {
-                    deprecationLogger.deprecate(
-                        "ec2_invalid_key_settings",
-                        "Setting [{}] is set but [{}] is not, which will be unsupported in future",
+                    throw new SettingsException(
+                        "Setting [{}] is set but [{}] is not",
                         SECRET_KEY_SETTING.getKey(),
-                        ACCESS_KEY_SETTING.getKey()
+                        ACCESS_KEY_SETTING.getKey(),
+                        SECRET_KEY_SETTING.getKey()
                     );
                 }
                 if (secret.length() == 0) {
-                    deprecationLogger.deprecate(
-                        "ec2_invalid_settings",
-                        "Setting [{}] is set but [{}] is not, which will be unsupported in future",
+                    throw new SettingsException(
+                        "Setting [{}] is set but [{}] is not",
                         ACCESS_KEY_SETTING.getKey(),
                         SECRET_KEY_SETTING.getKey()
                     );
                 }
 
-                final AWSCredentials credentials;
+                final AwsCredentials credentials;
                 if (sessionToken.length() == 0) {
                     logger.debug("Using basic key/secret credentials");
-                    credentials = new BasicAWSCredentials(key.toString(), secret.toString());
+                    credentials = AwsBasicCredentials.create(key.toString(), secret.toString());
                 } else {
                     logger.debug("Using basic session credentials");
-                    credentials = new BasicSessionCredentials(key.toString(), secret.toString(), sessionToken.toString());
+                    credentials = AwsSessionCredentials.create(key.toString(), secret.toString(), sessionToken.toString());
                 }
                 return credentials;
             }
         }
     }
 
-    // pkg private for tests
     /** Parse settings for a single client. */
     static Ec2ClientSettings getClientSettings(Settings settings) {
-        final AWSCredentials credentials = loadCredentials(settings);
+        final AwsCredentials credentials = loadCredentials(settings);
         try (
             SecureString proxyUsername = PROXY_USERNAME_SETTING.get(settings);
             SecureString proxyPassword = PROXY_PASSWORD_SETTING.get(settings)
@@ -213,6 +227,7 @@ static Ec2ClientSettings getClientSettings(Settings settings) {
             return new Ec2ClientSettings(
                 credentials,
                 ENDPOINT_SETTING.get(settings),
+                REGION_SETTING.get(settings),
                 PROTOCOL_SETTING.get(settings),
                 PROXY_HOST_SETTING.get(settings),
                 PROXY_PORT_SETTING.get(settings),
@@ -222,5 +237,4 @@ static Ec2ClientSettings getClientSettings(Settings settings) {
             );
         }
     }
-
 }
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2DiscoveryPlugin.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2DiscoveryPlugin.java
index ef89a351e5767..eb02e99582f93 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2DiscoveryPlugin.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2DiscoveryPlugin.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.util.EC2MetadataUtils;
-import com.amazonaws.util.json.Jackson;
+import software.amazon.awssdk.core.SdkSystemSetting;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.SpecialPermission;
@@ -56,12 +56,11 @@
 import java.net.URL;
 import java.net.URLConnection;
 import java.nio.charset.StandardCharsets;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.function.Supplier;
 
 public class Ec2DiscoveryPlugin extends Plugin implements DiscoveryPlugin, ReloadablePlugin {
@@ -71,20 +70,6 @@ public class Ec2DiscoveryPlugin extends Plugin implements DiscoveryPlugin, Reloa
 
     static {
         SpecialPermission.check();
-        // Initializing Jackson requires RuntimePermission accessDeclaredMembers
-        // The ClientConfiguration class requires RuntimePermission getClassLoader
-        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
-            try {
-                // kick jackson to do some static caching of declared members info
-                Jackson.jsonNodeOf("{}");
-                // ClientConfiguration clinit has some classloader problems
-                // TODO: fix that
-                Class.forName("com.amazonaws.ClientConfiguration");
-            } catch (final ClassNotFoundException e) {
-                throw new RuntimeException(e);
-            }
-            return null;
-        });
     }
 
     private final Settings settings;
@@ -121,6 +106,7 @@ public List<Setting<?>> getSettings() {
             Ec2ClientSettings.SECRET_KEY_SETTING,
             Ec2ClientSettings.SESSION_TOKEN_SETTING,
             Ec2ClientSettings.ENDPOINT_SETTING,
+            Ec2ClientSettings.REGION_SETTING,
             Ec2ClientSettings.PROTOCOL_SETTING,
             Ec2ClientSettings.PROXY_HOST_SETTING,
             Ec2ClientSettings.PROXY_PORT_SETTING,
@@ -143,9 +129,15 @@ public Settings additionalSettings() {
         final Settings.Builder builder = Settings.builder();
 
         // Adds a node attribute for the ec2 availability zone
-        final String azMetadataUrl = EC2MetadataUtils.getHostAddressForEC2MetadataService()
-            + "/latest/meta-data/placement/availability-zone";
-        builder.put(getAvailabilityZoneNodeAttributes(settings, azMetadataUrl));
+        Optional<String> ec2MetadataServiceEndpoint = SdkSystemSetting.AWS_EC2_METADATA_SERVICE_ENDPOINT.getStringValue();
+        if (ec2MetadataServiceEndpoint.isPresent()) {
+            builder.put(
+                getAvailabilityZoneNodeAttributes(
+                    settings,
+                    ec2MetadataServiceEndpoint.get() + "/latest/meta-data/placement/availability-zone"
+                )
+            );
+        }
         return builder.build();
     }
 
@@ -161,6 +153,9 @@ static Settings getAvailabilityZoneNodeAttributes(Settings settings, String azMe
         final URLConnection urlConnection;
         try {
             url = new URL(azMetadataUrl);
+            // Obtain the current EC2 instance availability zone from IMDS.
+            // Same as curl http://169.254.169.254/latest/meta-data/placement/availability-zone/.
+            // TODO: use EC2MetadataUtils::getAvailabilityZone that was added in AWS SDK v2 instead of rolling our own
             logger.debug("obtaining ec2 [placement/availability-zone] from ec2 meta-data url {}", url);
             urlConnection = SocketAccess.doPrivilegedIOException(url::openConnection);
             urlConnection.setConnectTimeout(2000);
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
index 9fa479e90c956..7efaf41bc3133 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.util.EC2MetadataUtils;
+import software.amazon.awssdk.core.SdkSystemSetting;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.network.NetworkService.CustomNameResolver;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -48,6 +48,7 @@
 import java.net.URL;
 import java.net.URLConnection;
 import java.nio.charset.StandardCharsets;
+import java.util.Optional;
 
 /**
  * Resolves certain ec2 related 'meta' hostnames into an actual hostname
@@ -104,25 +105,31 @@ private enum Ec2HostnameType {
     @SuppressForbidden(reason = "We call getInputStream in doPrivileged and provide SocketPermission")
     public InetAddress[] resolve(Ec2HostnameType type) throws IOException {
         InputStream in = null;
-        String metadataUrl = EC2MetadataUtils.getHostAddressForEC2MetadataService() + "/latest/meta-data/" + type.ec2Name;
-        try {
-            URL url = new URL(metadataUrl);
-            logger.debug("obtaining ec2 hostname from ec2 meta-data url {}", url);
-            URLConnection urlConnection = SocketAccess.doPrivilegedIOException(url::openConnection);
-            urlConnection.setConnectTimeout(2000);
-            in = SocketAccess.doPrivilegedIOException(urlConnection::getInputStream);
-            BufferedReader urlReader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));
-
-            String metadataResult = urlReader.readLine();
-            if (metadataResult == null || metadataResult.length() == 0) {
-                throw new IOException("no gce metadata returned from [" + url + "] for [" + type.configName + "]");
+        Optional<String> ec2MetadataServiceEndpoint = SdkSystemSetting.AWS_EC2_METADATA_SERVICE_ENDPOINT.getStringValue();
+        if (ec2MetadataServiceEndpoint.isPresent()) {
+            String metadataUrl = ec2MetadataServiceEndpoint.get() + "/latest/meta-data/" + type.ec2Name;
+            try {
+                URL url = new URL(metadataUrl);
+                logger.debug("obtaining ec2 hostname from ec2 meta-data url {}", url);
+                URLConnection urlConnection = SocketAccess.doPrivilegedIOException(url::openConnection);
+                urlConnection.setConnectTimeout(2000);
+                in = SocketAccess.doPrivilegedIOException(urlConnection::getInputStream);
+                BufferedReader urlReader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));
+
+                String metadataResult = urlReader.readLine();
+                if (metadataResult == null || metadataResult.length() == 0) {
+                    throw new IOException("no ec2 metadata returned from [" + url + "] for [" + type.configName + "]");
+                }
+                logger.debug("obtained ec2 hostname from ec2 meta-data url {}: {}", url, metadataResult);
+                // only one address: because we explicitly ask for only one via the Ec2HostnameType
+                return new InetAddress[] { InetAddress.getByName(metadataResult) };
+            } catch (IOException e) {
+                throw new IOException("IOException caught when fetching InetAddress from [" + metadataUrl + "]", e);
+            } finally {
+                IOUtils.closeWhileHandlingException(in);
             }
-            // only one address: because we explicitly ask for only one via the Ec2HostnameType
-            return new InetAddress[] { InetAddress.getByName(metadataResult) };
-        } catch (IOException e) {
-            throw new IOException("IOException caught when fetching InetAddress from [" + metadataUrl + "]", e);
-        } finally {
-            IOUtils.closeWhileHandlingException(in);
+        } else {
+            throw new IOException("Missing ec2 meta-data url (AWS_EC2_METADATA_SERVICE_ENDPOINT)");
         }
     }
 
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/SocketAccess.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/SocketAccess.java
index 292a3b167f5ad..c6605002c4462 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/SocketAccess.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/SocketAccess.java
@@ -50,6 +50,14 @@ final class SocketAccess {
 
     private SocketAccess() {}
 
+    public static void doPrivilegedVoid(Runnable action) {
+        SpecialPermission.check();
+        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
+            action.run();
+            return null;
+        });
+    }
+
     public static <T> T doPrivileged(PrivilegedAction<T> operation) {
         SpecialPermission.check();
         return AccessController.doPrivileged(operation);
diff --git a/plugins/discovery-ec2/src/main/plugin-metadata/plugin-security.policy b/plugins/discovery-ec2/src/main/plugin-metadata/plugin-security.policy
index 65dd1d13b5a6d..8712fab93620e 100644
--- a/plugins/discovery-ec2/src/main/plugin-metadata/plugin-security.policy
+++ b/plugins/discovery-ec2/src/main/plugin-metadata/plugin-security.policy
@@ -42,4 +42,13 @@ grant {
   permission java.net.SocketPermission "*", "connect";
 
   permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
+
+  permission java.util.PropertyPermission "aws.sharedCredentialsFile", "read,write";
+  permission java.util.PropertyPermission "aws.configFile", "read,write";
+  permission java.util.PropertyPermission "aws.region", "read,write";
+  permission java.util.PropertyPermission "aws.accessKeyId", "read,write";
+  permission java.util.PropertyPermission "aws.secretAccessKey", "read,write";
+  permission java.util.PropertyPermission "opensearch.path.conf", "read,write";
+
+  permission java.io.FilePermission "config", "read";
 };
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEC2MockAPITestCase.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEC2MockAPITestCase.java
deleted file mode 100644
index 51b48a8a45f21..0000000000000
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEC2MockAPITestCase.java
+++ /dev/null
@@ -1,226 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.discovery.ec2;
-
-import com.amazonaws.services.ec2.model.Instance;
-import com.amazonaws.services.ec2.model.Tag;
-import com.sun.net.httpserver.HttpServer;
-import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.network.NetworkService;
-import org.opensearch.common.settings.MockSecureSettings;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.test.transport.MockTransportService;
-import org.opensearch.threadpool.TestThreadPool;
-import org.opensearch.threadpool.ThreadPool;
-import org.junit.After;
-import org.junit.Before;
-
-import javax.xml.XMLConstants;
-import javax.xml.stream.XMLOutputFactory;
-import javax.xml.stream.XMLStreamWriter;
-
-import java.io.StringWriter;
-import java.net.InetAddress;
-import java.net.InetSocketAddress;
-import java.util.Collections;
-import java.util.List;
-import java.util.UUID;
-
-import static java.nio.charset.StandardCharsets.UTF_8;
-
-@SuppressForbidden(reason = "use a http server")
-public abstract class AbstractEC2MockAPITestCase extends OpenSearchTestCase {
-
-    protected HttpServer httpServer;
-
-    protected ThreadPool threadPool;
-
-    protected MockTransportService transportService;
-
-    protected NetworkService networkService = new NetworkService(Collections.emptyList());
-
-    @Before
-    public void setUp() throws Exception {
-        httpServer = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
-        httpServer.start();
-        threadPool = new TestThreadPool(EC2RetriesTests.class.getName());
-        transportService = createTransportService();
-        super.setUp();
-    }
-
-    protected abstract MockTransportService createTransportService();
-
-    protected Settings buildSettings(String accessKey) {
-        final InetSocketAddress address = httpServer.getAddress();
-        final String endpoint = "http://" + InetAddresses.toUriString(address.getAddress()) + ":" + address.getPort();
-        final MockSecureSettings mockSecure = new MockSecureSettings();
-        mockSecure.setString(Ec2ClientSettings.ACCESS_KEY_SETTING.getKey(), accessKey);
-        mockSecure.setString(Ec2ClientSettings.SECRET_KEY_SETTING.getKey(), "ec2_secret");
-        return Settings.builder().put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), endpoint).setSecureSettings(mockSecure).build();
-    }
-
-    @After
-    public void tearDown() throws Exception {
-        try {
-            IOUtils.close(transportService, () -> terminate(threadPool), () -> httpServer.stop(0));
-        } finally {
-            super.tearDown();
-        }
-    }
-
-    /**
-     * Generates a XML response that describe the EC2 instances
-     * TODO: org.opensearch.discovery.ec2.AmazonEC2Fixture uses pretty much the same code. We should dry up that test fixture.
-     */
-    static byte[] generateDescribeInstancesResponse(List<Instance> instances) {
-        final XMLOutputFactory xmlOutputFactory = XMLOutputFactory.newFactory();
-        xmlOutputFactory.setProperty(XMLOutputFactory.IS_REPAIRING_NAMESPACES, true);
-
-        final StringWriter out = new StringWriter();
-        XMLStreamWriter sw;
-        try {
-            sw = xmlOutputFactory.createXMLStreamWriter(out);
-            sw.writeStartDocument();
-
-            String namespace = "http://ec2.amazonaws.com/doc/2013-02-01/";
-            sw.setDefaultNamespace(namespace);
-            sw.writeStartElement(XMLConstants.DEFAULT_NS_PREFIX, "DescribeInstancesResponse", namespace);
-            {
-                sw.writeStartElement("requestId");
-                sw.writeCharacters(UUID.randomUUID().toString());
-                sw.writeEndElement();
-
-                sw.writeStartElement("reservationSet");
-                {
-                    for (Instance instance : instances) {
-                        sw.writeStartElement("item");
-                        {
-                            sw.writeStartElement("reservationId");
-                            sw.writeCharacters(UUID.randomUUID().toString());
-                            sw.writeEndElement();
-
-                            sw.writeStartElement("instancesSet");
-                            {
-                                sw.writeStartElement("item");
-                                {
-                                    sw.writeStartElement("instanceId");
-                                    sw.writeCharacters(instance.getInstanceId());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("imageId");
-                                    sw.writeCharacters(instance.getImageId());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("instanceState");
-                                    {
-                                        sw.writeStartElement("code");
-                                        sw.writeCharacters("16");
-                                        sw.writeEndElement();
-
-                                        sw.writeStartElement("name");
-                                        sw.writeCharacters("running");
-                                        sw.writeEndElement();
-                                    }
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("privateDnsName");
-                                    sw.writeCharacters(instance.getPrivateDnsName());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("dnsName");
-                                    sw.writeCharacters(instance.getPublicDnsName());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("instanceType");
-                                    sw.writeCharacters("m1.medium");
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("placement");
-                                    {
-                                        sw.writeStartElement("availabilityZone");
-                                        sw.writeCharacters("use-east-1e");
-                                        sw.writeEndElement();
-
-                                        sw.writeEmptyElement("groupName");
-
-                                        sw.writeStartElement("tenancy");
-                                        sw.writeCharacters("default");
-                                        sw.writeEndElement();
-                                    }
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("privateIpAddress");
-                                    sw.writeCharacters(instance.getPrivateIpAddress());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("ipAddress");
-                                    sw.writeCharacters(instance.getPublicIpAddress());
-                                    sw.writeEndElement();
-
-                                    sw.writeStartElement("tagSet");
-                                    for (Tag tag : instance.getTags()) {
-                                        sw.writeStartElement("item");
-                                        {
-                                            sw.writeStartElement("key");
-                                            sw.writeCharacters(tag.getKey());
-                                            sw.writeEndElement();
-
-                                            sw.writeStartElement("value");
-                                            sw.writeCharacters(tag.getValue());
-                                            sw.writeEndElement();
-                                        }
-                                        sw.writeEndElement();
-                                    }
-                                    sw.writeEndElement();
-                                }
-                                sw.writeEndElement();
-                            }
-                            sw.writeEndElement();
-                        }
-                        sw.writeEndElement();
-                    }
-                    sw.writeEndElement();
-                }
-                sw.writeEndElement();
-
-                sw.writeEndDocument();
-                sw.flush();
-            }
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
-        return out.toString().getBytes(UTF_8);
-    }
-}
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2DiscoveryTestCase.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2DiscoveryTestCase.java
new file mode 100644
index 0000000000000..5250f8d88855e
--- /dev/null
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2DiscoveryTestCase.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.discovery.ec2;
+
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.file.Path;
+
+public abstract class AbstractEc2DiscoveryTestCase extends OpenSearchTestCase {
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        setUpAwsProfile();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        resetAwsProfile();
+        super.tearDown();
+    }
+
+    private Path configPath() {
+        return PathUtils.get("config");
+    }
+
+    private String previousOpenSearchPathConf;
+    private String awsRegion;
+    private String awsAccessKeyId;
+    private String awsSecretAccessKey;
+    private String awsSharedCredentialsFile;
+    private String awsConfigFile;
+
+    @SuppressForbidden(reason = "set predictable aws defaults")
+    private void setUpAwsProfile() throws Exception {
+        previousOpenSearchPathConf = SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
+        awsRegion = SocketAccess.doPrivileged(() -> System.setProperty("aws.region", "us-west-2"));
+        awsAccessKeyId = SocketAccess.doPrivileged(() -> System.setProperty("aws.accessKeyId", "aws-access-key-id"));
+        awsSecretAccessKey = SocketAccess.doPrivileged(() -> System.setProperty("aws.secretAccessKey", "aws-secret-access-key"));
+        awsSharedCredentialsFile = System.getProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property());
+        awsConfigFile = System.getProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property());
+        SocketAccess.doPrivilegedVoid(AwsEc2ServiceImpl::setDefaultAwsProfilePath);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetAwsProfile() throws Exception {
+        resetPropertyValue("opensearch.path.conf", previousOpenSearchPathConf);
+        resetPropertyValue("aws.region", awsRegion);
+        resetPropertyValue("aws.accessKeyId", awsAccessKeyId);
+        resetPropertyValue("aws.secretAccessKey", awsSecretAccessKey);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), awsSharedCredentialsFile);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), awsConfigFile);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetPropertyValue(String key, String value) {
+        if (value != null) {
+            SocketAccess.doPrivileged(() -> System.setProperty(key, value));
+        } else {
+            SocketAccess.doPrivileged(() -> System.clearProperty(key));
+        }
+    }
+}
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2MockAPITestCase.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2MockAPITestCase.java
new file mode 100644
index 0000000000000..595c51bdb1f47
--- /dev/null
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AbstractEc2MockAPITestCase.java
@@ -0,0 +1,231 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery.ec2;
+
+import com.sun.net.httpserver.HttpServer;
+
+import software.amazon.awssdk.services.ec2.model.Instance;
+import software.amazon.awssdk.services.ec2.model.Tag;
+
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.network.InetAddresses;
+import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.MockSecureSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import javax.xml.XMLConstants;
+import javax.xml.stream.XMLOutputFactory;
+import javax.xml.stream.XMLStreamWriter;
+
+import java.io.StringWriter;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.util.Collections;
+import java.util.List;
+import java.util.UUID;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+@SuppressForbidden(reason = "use a http server")
+public abstract class AbstractEc2MockAPITestCase extends AbstractEc2DiscoveryTestCase {
+
+    protected HttpServer httpServer;
+
+    protected ThreadPool threadPool;
+
+    protected MockTransportService transportService;
+
+    protected NetworkService networkService = new NetworkService(Collections.emptyList());
+
+    @Before
+    public void setUp() throws Exception {
+        httpServer = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        httpServer.start();
+        threadPool = new TestThreadPool(Ec2RetriesTests.class.getName());
+        transportService = createTransportService();
+        super.setUp();
+    }
+
+    protected abstract MockTransportService createTransportService();
+
+    protected Settings buildSettings(String accessKey) {
+        final InetSocketAddress address = httpServer.getAddress();
+        final String endpoint = "http://" + InetAddresses.toUriString(address.getAddress()) + ":" + address.getPort();
+        final MockSecureSettings mockSecure = new MockSecureSettings();
+        mockSecure.setString(Ec2ClientSettings.ACCESS_KEY_SETTING.getKey(), accessKey);
+        mockSecure.setString(Ec2ClientSettings.SECRET_KEY_SETTING.getKey(), "ec2_secret");
+        return Settings.builder()
+            .put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), endpoint)
+            .put(Ec2ClientSettings.REGION_SETTING.getKey(), "ec2_region")
+            .setSecureSettings(mockSecure)
+            .build();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        try {
+            IOUtils.close(transportService, () -> terminate(threadPool), () -> httpServer.stop(0));
+        } finally {
+            super.tearDown();
+        }
+    }
+
+    /**
+     * Generates a XML response that describe the EC2 instances
+     * TODO: org.opensearch.discovery.ec2.AmazonEC2Fixture uses pretty much the same code. We should dry up that test fixture.
+     */
+    static byte[] generateDescribeInstancesResponse(List<Instance> instances) {
+        final XMLOutputFactory xmlOutputFactory = XMLOutputFactory.newFactory();
+        xmlOutputFactory.setProperty(XMLOutputFactory.IS_REPAIRING_NAMESPACES, true);
+
+        final StringWriter out = new StringWriter();
+        XMLStreamWriter sw;
+        try {
+            sw = xmlOutputFactory.createXMLStreamWriter(out);
+            sw.writeStartDocument();
+
+            String namespace = "http://ec2.amazonaws.com/doc/2013-02-01/";
+            sw.setDefaultNamespace(namespace);
+            sw.writeStartElement(XMLConstants.DEFAULT_NS_PREFIX, "DescribeInstancesResponse", namespace);
+            {
+                sw.writeStartElement("requestId");
+                sw.writeCharacters(UUID.randomUUID().toString());
+                sw.writeEndElement();
+
+                sw.writeStartElement("reservationSet");
+                {
+                    for (Instance instance : instances) {
+                        sw.writeStartElement("item");
+                        {
+                            sw.writeStartElement("reservationId");
+                            sw.writeCharacters(UUID.randomUUID().toString());
+                            sw.writeEndElement();
+
+                            sw.writeStartElement("instancesSet");
+                            {
+                                sw.writeStartElement("item");
+                                {
+                                    sw.writeStartElement("instanceId");
+                                    sw.writeCharacters(instance.instanceId());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("imageId");
+                                    sw.writeCharacters(instance.imageId());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("instanceState");
+                                    {
+                                        sw.writeStartElement("code");
+                                        sw.writeCharacters("16");
+                                        sw.writeEndElement();
+
+                                        sw.writeStartElement("name");
+                                        sw.writeCharacters("running");
+                                        sw.writeEndElement();
+                                    }
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("privateDnsName");
+                                    sw.writeCharacters(instance.privateDnsName());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("dnsName");
+                                    sw.writeCharacters(instance.publicDnsName());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("instanceType");
+                                    sw.writeCharacters("m1.medium");
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("placement");
+                                    {
+                                        sw.writeStartElement("availabilityZone");
+                                        sw.writeCharacters("use-east-1e");
+                                        sw.writeEndElement();
+
+                                        sw.writeEmptyElement("groupName");
+
+                                        sw.writeStartElement("tenancy");
+                                        sw.writeCharacters("default");
+                                        sw.writeEndElement();
+                                    }
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("privateIpAddress");
+                                    sw.writeCharacters(instance.privateIpAddress());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("ipAddress");
+                                    sw.writeCharacters(instance.publicIpAddress());
+                                    sw.writeEndElement();
+
+                                    sw.writeStartElement("tagSet");
+                                    for (Tag tag : instance.tags()) {
+                                        sw.writeStartElement("item");
+                                        {
+                                            sw.writeStartElement("key");
+                                            sw.writeCharacters(tag.key());
+                                            sw.writeEndElement();
+
+                                            sw.writeStartElement("value");
+                                            sw.writeCharacters(tag.value());
+                                            sw.writeEndElement();
+                                        }
+                                        sw.writeEndElement();
+                                    }
+                                    sw.writeEndElement();
+                                }
+                                sw.writeEndElement();
+                            }
+                            sw.writeEndElement();
+                        }
+                        sw.writeEndElement();
+                    }
+                    sw.writeEndElement();
+                }
+                sw.writeEndElement();
+
+                sw.writeEndDocument();
+                sw.flush();
+            }
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+        return out.toString().getBytes(UTF_8);
+    }
+}
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AwsEc2ServiceImplTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AwsEc2ServiceImplTests.java
index 3150f96443695..81310f7e2e3c3 100644
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AwsEc2ServiceImplTests.java
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/AwsEc2ServiceImplTests.java
@@ -32,40 +32,40 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.Protocol;
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.BasicSessionCredentials;
-import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.core.Protocol;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
-import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
 
-public class AwsEc2ServiceImplTests extends OpenSearchTestCase {
-
-    public void testAWSCredentialsWithSystemProviders() {
-        final AWSCredentialsProvider credentialsProvider = AwsEc2ServiceImpl.buildCredentials(
+public class AwsEc2ServiceImplTests extends AbstractEc2DiscoveryTestCase {
+    public void testAwsCredentialsWithSystemProviders() {
+        final AwsCredentialsProvider credentialsProvider = AwsEc2ServiceImpl.buildCredentials(
             logger,
             Ec2ClientSettings.getClientSettings(Settings.EMPTY)
         );
-        assertThat(credentialsProvider, instanceOf(DefaultAWSCredentialsProviderChain.class));
+        assertThat(credentialsProvider, instanceOf(AwsCredentialsProvider.class));
     }
 
-    public void testAWSCredentialsWithOpenSearchAwsSettings() {
+    public void testAwsCredentialsWithOpenSearchAwsSettings() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         secureSettings.setString("discovery.ec2.access_key", "aws_key");
         secureSettings.setString("discovery.ec2.secret_key", "aws_secret");
-        final AWSCredentials credentials = AwsEc2ServiceImpl.buildCredentials(
+        final AwsCredentials credentials = AwsEc2ServiceImpl.buildCredentials(
             logger,
             Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
-        ).getCredentials();
-        assertThat(credentials.getAWSAccessKeyId(), is("aws_key"));
-        assertThat(credentials.getAWSSecretKey(), is("aws_secret"));
+        ).resolveCredentials();
+        assertThat(credentials.accessKeyId(), is("aws_key"));
+        assertThat(credentials.secretAccessKey(), is("aws_secret"));
     }
 
     public void testAWSSessionCredentialsWithOpenSearchAwsSettings() {
@@ -73,43 +73,39 @@ public void testAWSSessionCredentialsWithOpenSearchAwsSettings() {
         secureSettings.setString("discovery.ec2.access_key", "aws_key");
         secureSettings.setString("discovery.ec2.secret_key", "aws_secret");
         secureSettings.setString("discovery.ec2.session_token", "aws_session_token");
-        final BasicSessionCredentials credentials = (BasicSessionCredentials) AwsEc2ServiceImpl.buildCredentials(
+        final AwsSessionCredentials credentials = (AwsSessionCredentials) AwsEc2ServiceImpl.buildCredentials(
             logger,
             Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
-        ).getCredentials();
-        assertThat(credentials.getAWSAccessKeyId(), is("aws_key"));
-        assertThat(credentials.getAWSSecretKey(), is("aws_secret"));
-        assertThat(credentials.getSessionToken(), is("aws_session_token"));
+        ).resolveCredentials();
+        assertThat(credentials.accessKeyId(), is("aws_key"));
+        assertThat(credentials.secretAccessKey(), is("aws_secret"));
+        assertThat(credentials.sessionToken(), is("aws_session_token"));
     }
 
-    public void testDeprecationOfLoneAccessKey() {
+    public void testRejectionOfLoneAccessKey() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         secureSettings.setString("discovery.ec2.access_key", "aws_key");
-        final AWSCredentials credentials = AwsEc2ServiceImpl.buildCredentials(
-            logger,
-            Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
-        ).getCredentials();
-        assertThat(credentials.getAWSAccessKeyId(), is("aws_key"));
-        assertThat(credentials.getAWSSecretKey(), is(""));
-        assertSettingDeprecationsAndWarnings(
-            new String[] {},
-            "Setting [discovery.ec2.access_key] is set but [discovery.ec2.secret_key] is not, which will be unsupported in future"
+        SettingsException e = expectThrows(
+            SettingsException.class,
+            () -> AwsEc2ServiceImpl.buildCredentials(
+                logger,
+                Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
+            )
         );
+        assertThat(e.getMessage(), is("Setting [discovery.ec2.access_key] is set but [discovery.ec2.secret_key] is not"));
     }
 
     public void testDeprecationOfLoneSecretKey() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         secureSettings.setString("discovery.ec2.secret_key", "aws_secret");
-        final AWSCredentials credentials = AwsEc2ServiceImpl.buildCredentials(
-            logger,
-            Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
-        ).getCredentials();
-        assertThat(credentials.getAWSAccessKeyId(), is(""));
-        assertThat(credentials.getAWSSecretKey(), is("aws_secret"));
-        assertSettingDeprecationsAndWarnings(
-            new String[] {},
-            "Setting [discovery.ec2.secret_key] is set but [discovery.ec2.access_key] is not, which will be unsupported in future"
+        SettingsException e = expectThrows(
+            SettingsException.class,
+            () -> AwsEc2ServiceImpl.buildCredentials(
+                logger,
+                Ec2ClientSettings.getClientSettings(Settings.builder().setSecureSettings(secureSettings).build())
+            )
         );
+        assertThat(e.getMessage(), is("Setting [discovery.ec2.secret_key] is set but [discovery.ec2.access_key] is not"));
     }
 
     public void testRejectionOfLoneSessionToken() {
@@ -129,44 +125,81 @@ public void testRejectionOfLoneSessionToken() {
     }
 
     public void testAWSDefaultConfiguration() {
-        launchAWSConfigurationTest(Settings.EMPTY, Protocol.HTTPS, null, -1, null, null, ClientConfiguration.DEFAULT_SOCKET_TIMEOUT);
+        // proxy configuration
+        final ProxyConfiguration proxyConfiguration = AwsEc2ServiceImpl.buildProxyConfiguration(
+            logger,
+            Ec2ClientSettings.getClientSettings(Settings.EMPTY)
+        );
+
+        assertNull(proxyConfiguration.scheme());
+        assertNull(proxyConfiguration.host());
+        assertThat(proxyConfiguration.port(), is(0));
+        assertNull(proxyConfiguration.username());
+        assertNull(proxyConfiguration.password());
+
+        // retry policy
+        RetryPolicy retryPolicyConfiguration = AwsEc2ServiceImpl.buildRetryPolicy(
+            logger,
+            Ec2ClientSettings.getClientSettings(Settings.EMPTY)
+        );
+
+        assertThat(retryPolicyConfiguration.numRetries(), is(10));
+
+        final AwsCredentials credentials = AwsEc2ServiceImpl.buildCredentials(logger, Ec2ClientSettings.getClientSettings(Settings.EMPTY))
+            .resolveCredentials();
+
+        assertThat(credentials.accessKeyId(), is("aws-access-key-id"));
+        assertThat(credentials.secretAccessKey(), is("aws-secret-access-key"));
+
+        ClientOverrideConfiguration clientOverrideConfiguration = AwsEc2ServiceImpl.buildOverrideConfiguration(
+            logger,
+            Ec2ClientSettings.getClientSettings(Settings.EMPTY)
+        );
+        assertTrue(clientOverrideConfiguration.retryPolicy().isPresent());
+        assertThat(clientOverrideConfiguration.retryPolicy().get().numRetries(), is(10));
     }
 
     public void testAWSConfigurationWithAwsSettings() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         secureSettings.setString("discovery.ec2.proxy.username", "aws_proxy_username");
         secureSettings.setString("discovery.ec2.proxy.password", "aws_proxy_password");
+
         final Settings settings = Settings.builder()
             .put("discovery.ec2.protocol", "http")
-            .put("discovery.ec2.proxy.host", "aws_proxy_host")
+            // NOTE: a host cannot contain the _ character when parsed by URI, hence aws-proxy-host and not aws_proxy_host
+            .put("discovery.ec2.proxy.host", "aws-proxy-host")
             .put("discovery.ec2.proxy.port", 8080)
             .put("discovery.ec2.read_timeout", "10s")
             .setSecureSettings(secureSettings)
             .build();
-        launchAWSConfigurationTest(settings, Protocol.HTTP, "aws_proxy_host", 8080, "aws_proxy_username", "aws_proxy_password", 10000);
-    }
 
-    protected void launchAWSConfigurationTest(
-        Settings settings,
-        Protocol expectedProtocol,
-        String expectedProxyHost,
-        int expectedProxyPort,
-        String expectedProxyUsername,
-        String expectedProxyPassword,
-        int expectedReadTimeout
-    ) {
-        final ClientConfiguration configuration = AwsEc2ServiceImpl.buildConfiguration(
+        // proxy configuration
+        final ProxyConfiguration proxyConfiguration = AwsEc2ServiceImpl.buildProxyConfiguration(
             logger,
             Ec2ClientSettings.getClientSettings(settings)
         );
 
-        assertThat(configuration.getResponseMetadataCacheSize(), is(0));
-        assertThat(configuration.getProtocol(), is(expectedProtocol));
-        assertThat(configuration.getProxyHost(), is(expectedProxyHost));
-        assertThat(configuration.getProxyPort(), is(expectedProxyPort));
-        assertThat(configuration.getProxyUsername(), is(expectedProxyUsername));
-        assertThat(configuration.getProxyPassword(), is(expectedProxyPassword));
-        assertThat(configuration.getSocketTimeout(), is(expectedReadTimeout));
-    }
+        assertThat(proxyConfiguration.scheme(), is(Protocol.HTTP.toString()));
+        assertThat(proxyConfiguration.host(), is("aws-proxy-host"));
+        assertThat(proxyConfiguration.port(), is(8080));
+        assertThat(proxyConfiguration.username(), is("aws_proxy_username"));
+        assertThat(proxyConfiguration.password(), is("aws_proxy_password"));
+
+        // retry policy
+        RetryPolicy retryPolicyConfiguration = AwsEc2ServiceImpl.buildRetryPolicy(logger, Ec2ClientSettings.getClientSettings(settings));
+        assertThat(retryPolicyConfiguration.numRetries(), is(10));
+
+        final AwsCredentials credentials = AwsEc2ServiceImpl.buildCredentials(logger, Ec2ClientSettings.getClientSettings(Settings.EMPTY))
+            .resolveCredentials();
 
+        assertThat(credentials.accessKeyId(), is("aws-access-key-id"));
+        assertThat(credentials.secretAccessKey(), is("aws-secret-access-key"));
+
+        ClientOverrideConfiguration clientOverrideConfiguration = AwsEc2ServiceImpl.buildOverrideConfiguration(
+            logger,
+            Ec2ClientSettings.getClientSettings(Settings.EMPTY)
+        );
+        assertTrue(clientOverrideConfiguration.retryPolicy().isPresent());
+        assertThat(clientOverrideConfiguration.retryPolicy().get().numRetries(), is(10));
+    }
 }
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/EC2RetriesTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/EC2RetriesTests.java
deleted file mode 100644
index 9443eed5efae9..0000000000000
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/EC2RetriesTests.java
+++ /dev/null
@@ -1,140 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.discovery.ec2;
-
-import com.amazonaws.http.HttpMethodName;
-import com.amazonaws.services.ec2.model.Instance;
-import org.apache.http.HttpStatus;
-import org.apache.http.NameValuePair;
-import org.apache.http.client.utils.URLEncodedUtils;
-import org.opensearch.Version;
-import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.Streams;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.discovery.SeedHostsProvider;
-import org.opensearch.discovery.SeedHostsResolver;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.test.transport.MockTransportService;
-import org.opensearch.transport.TransportService;
-import org.opensearch.transport.nio.MockNioTransport;
-import org.hamcrest.Matchers;
-
-import java.io.IOException;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.stream.Collectors;
-
-import static java.nio.charset.StandardCharsets.UTF_8;
-import static org.hamcrest.Matchers.aMapWithSize;
-import static org.hamcrest.Matchers.is;
-
-@SuppressForbidden(reason = "use a http server")
-public class EC2RetriesTests extends AbstractEC2MockAPITestCase {
-
-    @Override
-    protected MockTransportService createTransportService() {
-        return new MockTransportService(
-            Settings.EMPTY,
-            new MockNioTransport(
-                Settings.EMPTY,
-                Version.CURRENT,
-                threadPool,
-                networkService,
-                PageCacheRecycler.NON_RECYCLING_INSTANCE,
-                new NamedWriteableRegistry(Collections.emptyList()),
-                new NoneCircuitBreakerService()
-            ),
-            threadPool,
-            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
-            null
-        );
-    }
-
-    public void testEC2DiscoveryRetriesOnRateLimiting() throws IOException {
-        final String accessKey = "ec2_access";
-        final List<String> hosts = Collections.singletonList("127.0.0.1:9300");
-        final Map<String, Integer> failedRequests = new ConcurrentHashMap<>();
-        // retry the same request 5 times at most
-        final int maxRetries = randomIntBetween(1, 5);
-        httpServer.createContext("/", exchange -> {
-            if (exchange.getRequestMethod().equals(HttpMethodName.POST.name())) {
-                final String request = Streams.readFully(exchange.getRequestBody()).utf8ToString();
-                final String userAgent = exchange.getRequestHeaders().getFirst("User-Agent");
-                if (userAgent != null && userAgent.startsWith("aws-sdk-java")) {
-                    final String auth = exchange.getRequestHeaders().getFirst("Authorization");
-                    if (auth == null || auth.contains(accessKey) == false) {
-                        throw new IllegalArgumentException("wrong access key: " + auth);
-                    }
-                    if (failedRequests.compute(
-                        exchange.getRequestHeaders().getFirst("Amz-sdk-invocation-id"),
-                        (requestId, count) -> (count == null ? 0 : count) + 1
-                    ) < maxRetries) {
-                        exchange.sendResponseHeaders(HttpStatus.SC_SERVICE_UNAVAILABLE, -1);
-                        return;
-                    }
-                    // Simulate an EC2 DescribeInstancesResponse
-                    byte[] responseBody = null;
-                    for (NameValuePair parse : URLEncodedUtils.parse(request, UTF_8)) {
-                        if ("Action".equals(parse.getName())) {
-                            responseBody = generateDescribeInstancesResponse(
-                                hosts.stream().map(address -> new Instance().withPublicIpAddress(address)).collect(Collectors.toList())
-                            );
-                            break;
-                        }
-                    }
-                    responseBody = responseBody == null ? new byte[0] : responseBody;
-                    exchange.getResponseHeaders().set("Content-Type", "text/xml; charset=UTF-8");
-                    exchange.sendResponseHeaders(HttpStatus.SC_OK, responseBody.length);
-                    exchange.getResponseBody().write(responseBody);
-                    return;
-                }
-            }
-            fail("did not send response");
-        });
-        try (Ec2DiscoveryPlugin plugin = new Ec2DiscoveryPlugin(buildSettings(accessKey))) {
-            final SeedHostsProvider seedHostsProvider = plugin.getSeedHostProviders(transportService, networkService).get("ec2").get();
-            final SeedHostsResolver resolver = new SeedHostsResolver("test", Settings.EMPTY, transportService, seedHostsProvider);
-            resolver.start();
-            final List<TransportAddress> addressList = seedHostsProvider.getSeedAddresses(null);
-            assertThat(addressList, Matchers.hasSize(1));
-            assertThat(addressList.get(0).toString(), is(hosts.get(0)));
-            assertThat(failedRequests, aMapWithSize(1));
-            assertThat(failedRequests.values().iterator().next(), is(maxRetries));
-        }
-    }
-}
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryPluginTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryPluginTests.java
index cb19c0d4255ac..bde508a0afe96 100644
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryPluginTests.java
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryPluginTests.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.BasicAWSCredentials;
-import com.amazonaws.auth.BasicSessionCredentials;
-import com.amazonaws.services.ec2.AbstractAmazonEC2;
-import com.amazonaws.services.ec2.AmazonEC2;
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.ec2.Ec2Client;
+
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.node.Node;
-import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -51,10 +52,8 @@
 import java.util.Arrays;
 
 import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.is;
-
-public class Ec2DiscoveryPluginTests extends OpenSearchTestCase {
 
+public class Ec2DiscoveryPluginTests extends AbstractEc2DiscoveryTestCase {
     private Settings getNodeAttributes(Settings settings, String url) {
         final Settings realSettings = Settings.builder().put(AwsEc2Service.AUTO_ATTRIBUTE_SETTING.getKey(), true).put(settings).build();
         return Ec2DiscoveryPlugin.getAvailabilityZoneNodeAttributes(realSettings, url);
@@ -103,16 +102,32 @@ public void testNodeAttributesErrorLenient() throws Exception {
 
     public void testDefaultEndpoint() throws IOException {
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(Settings.EMPTY)) {
-            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().get()).endpoint;
-            assertThat(endpoint, is(""));
+            final String endpoint = ((MockEc2Client) plugin.ec2Service.client().get()).endpoint;
+            assertEquals(endpoint, "");
+        }
+    }
+
+    public void testDefaultRegion() throws IOException {
+        final Settings settings = Settings.builder().build();
+        try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings)) {
+            final String region = ((MockEc2Client) plugin.ec2Service.client().get()).region;
+            assertEquals(region, "");
+        }
+    }
+
+    public void testSpecificRegion() throws IOException {
+        final Settings settings = Settings.builder().put(Ec2ClientSettings.REGION_SETTING.getKey(), "us-west-2").build();
+        try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings)) {
+            final String region = ((MockEc2Client) plugin.ec2Service.client().get()).region;
+            assertEquals(region, Region.US_WEST_2.toString());
         }
     }
 
     public void testSpecificEndpoint() throws IOException {
         final Settings settings = Settings.builder().put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), "ec2.endpoint").build();
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings)) {
-            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().get()).endpoint;
-            assertThat(endpoint, is("ec2.endpoint"));
+            final String endpoint = ((MockEc2Client) plugin.ec2Service.client().get()).endpoint;
+            assertEquals(endpoint, "ec2.endpoint");
         }
     }
 
@@ -127,8 +142,9 @@ public void testClientSettingsReInit() throws IOException {
         mockSecure1.setString(Ec2ClientSettings.PROXY_USERNAME_SETTING.getKey(), "proxy_username_1");
         mockSecure1.setString(Ec2ClientSettings.PROXY_PASSWORD_SETTING.getKey(), "proxy_password_1");
         final Settings settings1 = Settings.builder()
-            .put(Ec2ClientSettings.PROXY_HOST_SETTING.getKey(), "proxy_host_1")
+            .put(Ec2ClientSettings.PROXY_HOST_SETTING.getKey(), "proxy-host-1")
             .put(Ec2ClientSettings.PROXY_PORT_SETTING.getKey(), 881)
+            .put(Ec2ClientSettings.REGION_SETTING.getKey(), "ec2_region")
             .put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), "ec2_endpoint_1")
             .setSecureSettings(mockSecure1)
             .build();
@@ -142,62 +158,84 @@ public void testClientSettingsReInit() throws IOException {
         mockSecure2.setString(Ec2ClientSettings.PROXY_USERNAME_SETTING.getKey(), "proxy_username_2");
         mockSecure2.setString(Ec2ClientSettings.PROXY_PASSWORD_SETTING.getKey(), "proxy_password_2");
         final Settings settings2 = Settings.builder()
-            .put(Ec2ClientSettings.PROXY_HOST_SETTING.getKey(), "proxy_host_2")
+            .put(Ec2ClientSettings.PROXY_HOST_SETTING.getKey(), "proxy-host-2")
             .put(Ec2ClientSettings.PROXY_PORT_SETTING.getKey(), 882)
+            .put(Ec2ClientSettings.REGION_SETTING.getKey(), "ec2_region")
             .put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), "ec2_endpoint_2")
             .setSecureSettings(mockSecure2)
             .build();
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings1)) {
-            try (AmazonEc2Reference clientReference = plugin.ec2Service.client()) {
+            try (AmazonEc2ClientReference clientReference = plugin.ec2Service.client()) {
                 {
-                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
-                    assertThat(credentials.getAWSAccessKeyId(), is("ec2_access_1"));
-                    assertThat(credentials.getAWSSecretKey(), is("ec2_secret_1"));
+                    final MockEc2Client mockEc2Client = (MockEc2Client) clientReference.get();
+                    assertEquals(mockEc2Client.endpoint, "ec2_endpoint_1");
+
+                    final AwsCredentials credentials = mockEc2Client.credentials.resolveCredentials();
+                    assertEquals(credentials.accessKeyId(), "ec2_access_1");
+                    assertEquals(credentials.secretAccessKey(), "ec2_secret_1");
                     if (mockSecure1HasSessionToken) {
-                        assertThat(credentials, instanceOf(BasicSessionCredentials.class));
-                        assertThat(((BasicSessionCredentials) credentials).getSessionToken(), is("ec2_session_token_1"));
+                        assertThat(credentials, instanceOf(AwsSessionCredentials.class));
+                        assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "ec2_session_token_1");
                     } else {
-                        assertThat(credentials, instanceOf(BasicAWSCredentials.class));
+                        assertThat(credentials, instanceOf(AwsBasicCredentials.class));
                     }
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(881));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_1"));
+
+                    assertEquals(
+                        mockEc2Client.proxyConfiguration.toString(),
+                        "ProxyConfiguration(endpoint=https://proxy-host-1:881, username=proxy_username_1, preemptiveBasicAuthenticationEnabled=false)"
+                    );
+                    assertEquals(mockEc2Client.proxyConfiguration.host(), "proxy-host-1");
+                    assertEquals(mockEc2Client.proxyConfiguration.port(), 881);
+                    assertEquals(mockEc2Client.proxyConfiguration.username(), "proxy_username_1");
+                    assertEquals(mockEc2Client.proxyConfiguration.password(), "proxy_password_1");
                 }
                 // reload secure settings2
                 plugin.reload(settings2);
                 // client is not released, it is still using the old settings
                 {
-                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
+                    final MockEc2Client mockEc2Client = (MockEc2Client) clientReference.get();
+                    assertEquals(mockEc2Client.endpoint, "ec2_endpoint_1");
+
+                    final AwsCredentials credentials = ((MockEc2Client) clientReference.get()).credentials.resolveCredentials();
                     if (mockSecure1HasSessionToken) {
-                        assertThat(credentials, instanceOf(BasicSessionCredentials.class));
-                        assertThat(((BasicSessionCredentials) credentials).getSessionToken(), is("ec2_session_token_1"));
+                        assertThat(credentials, instanceOf(AwsSessionCredentials.class));
+                        assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "ec2_session_token_1");
                     } else {
-                        assertThat(credentials, instanceOf(BasicAWSCredentials.class));
+                        assertThat(credentials, instanceOf(AwsBasicCredentials.class));
                     }
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(881));
-                    assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_1"));
+
+                    assertEquals(
+                        mockEc2Client.proxyConfiguration.toString(),
+                        "ProxyConfiguration(endpoint=https://proxy-host-1:881, username=proxy_username_1, preemptiveBasicAuthenticationEnabled=false)"
+                    );
+                    assertEquals(mockEc2Client.proxyConfiguration.host(), "proxy-host-1");
+                    assertEquals(mockEc2Client.proxyConfiguration.port(), 881);
+                    assertEquals(mockEc2Client.proxyConfiguration.username(), "proxy_username_1");
+                    assertEquals(mockEc2Client.proxyConfiguration.password(), "proxy_password_1");
                 }
             }
-            try (AmazonEc2Reference clientReference = plugin.ec2Service.client()) {
-                final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
-                assertThat(credentials.getAWSAccessKeyId(), is("ec2_access_2"));
-                assertThat(credentials.getAWSSecretKey(), is("ec2_secret_2"));
+            try (AmazonEc2ClientReference clientReference = plugin.ec2Service.client()) {
+                final MockEc2Client mockEc2Client = (MockEc2Client) clientReference.get();
+                assertEquals(mockEc2Client.endpoint, "ec2_endpoint_2");
+
+                final AwsCredentials credentials = ((MockEc2Client) clientReference.get()).credentials.resolveCredentials();
+                assertEquals(credentials.accessKeyId(), "ec2_access_2");
+                assertEquals(credentials.secretAccessKey(), "ec2_secret_2");
                 if (mockSecure2HasSessionToken) {
-                    assertThat(credentials, instanceOf(BasicSessionCredentials.class));
-                    assertThat(((BasicSessionCredentials) credentials).getSessionToken(), is("ec2_session_token_2"));
+                    assertThat(credentials, instanceOf(AwsSessionCredentials.class));
+                    assertEquals(((AwsSessionCredentials) credentials).sessionToken(), "ec2_session_token_2");
                 } else {
-                    assertThat(credentials, instanceOf(BasicAWSCredentials.class));
+                    assertThat(credentials, instanceOf(AwsBasicCredentials.class));
                 }
-                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_2"));
-                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_2"));
-                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_2"));
-                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(882));
-                assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_2"));
+
+                assertEquals(
+                    mockEc2Client.proxyConfiguration.toString(),
+                    "ProxyConfiguration(endpoint=https://proxy-host-2:882, username=proxy_username_2, preemptiveBasicAuthenticationEnabled=false)"
+                );
+                assertEquals(mockEc2Client.proxyConfiguration.host(), "proxy-host-2");
+                assertEquals(mockEc2Client.proxyConfiguration.port(), 882);
+                assertEquals(mockEc2Client.proxyConfiguration.username(), "proxy_username_2");
+                assertEquals(mockEc2Client.proxyConfiguration.password(), "proxy_password_2");
             }
         }
     }
@@ -207,26 +245,53 @@ private static class Ec2DiscoveryPluginMock extends Ec2DiscoveryPlugin {
         Ec2DiscoveryPluginMock(Settings settings) {
             super(settings, new AwsEc2ServiceImpl() {
                 @Override
-                AmazonEC2 buildClient(AWSCredentialsProvider credentials, ClientConfiguration configuration, String endpoint) {
-                    return new AmazonEC2Mock(credentials, configuration, endpoint);
+                protected Ec2Client buildClient(
+                    AwsCredentialsProvider credentials,
+                    ProxyConfiguration proxyConfiguration,
+                    ClientOverrideConfiguration overrideConfiguration,
+                    String endpoint,
+                    String region,
+                    long readTimeoutMillis
+                ) {
+                    return new MockEc2Client(credentials, proxyConfiguration, overrideConfiguration, endpoint, region, readTimeoutMillis);
                 }
             });
         }
     }
 
-    private static class AmazonEC2Mock extends AbstractAmazonEC2 {
+    private static class MockEc2Client implements Ec2Client {
 
         String endpoint;
-        final AWSCredentialsProvider credentials;
-        final ClientConfiguration configuration;
+        final String region;
+        final AwsCredentialsProvider credentials;
+        final ClientOverrideConfiguration clientOverrideConfiguration;
+        final ProxyConfiguration proxyConfiguration;
+        final long readTimeoutMillis;
 
-        AmazonEC2Mock(AWSCredentialsProvider credentials, ClientConfiguration configuration, String endpoint) {
+        MockEc2Client(
+            AwsCredentialsProvider credentials,
+            ProxyConfiguration proxyConfiguration,
+            ClientOverrideConfiguration clientOverrideConfiguration,
+            String endpoint,
+            String region,
+            long readTimeoutMillis
+        ) {
             this.credentials = credentials;
-            this.configuration = configuration;
+            this.proxyConfiguration = proxyConfiguration;
+            this.clientOverrideConfiguration = clientOverrideConfiguration;
             this.endpoint = endpoint;
+            this.region = region;
+            this.readTimeoutMillis = readTimeoutMillis;
         }
 
         @Override
-        public void shutdown() {}
+        public String serviceName() {
+            return "ec2";
+        }
+
+        @Override
+        public void close() {
+            // ignore
+        }
     }
 }
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryTests.java
index f1870a1c487e0..02e1ff40f7ed6 100644
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryTests.java
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.discovery.ec2;
 
-import com.amazonaws.http.HttpMethodName;
-import com.amazonaws.services.ec2.model.Instance;
-import com.amazonaws.services.ec2.model.InstanceState;
-import com.amazonaws.services.ec2.model.InstanceStateName;
-import com.amazonaws.services.ec2.model.Tag;
+import software.amazon.awssdk.services.ec2.model.Instance;
+import software.amazon.awssdk.services.ec2.model.InstanceState;
+import software.amazon.awssdk.services.ec2.model.InstanceStateName;
+import software.amazon.awssdk.services.ec2.model.Tag;
+
 import org.apache.http.HttpStatus;
 import org.apache.http.NameValuePair;
 import org.apache.http.client.utils.URLEncodedUtils;
@@ -45,9 +45,10 @@
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportService;
@@ -72,7 +73,7 @@
 import static org.hamcrest.Matchers.is;
 
 @SuppressForbidden(reason = "use a http server")
-public class Ec2DiscoveryTests extends AbstractEC2MockAPITestCase {
+public class Ec2DiscoveryTests extends AbstractEc2MockAPITestCase {
 
     private static final String SUFFIX_PRIVATE_DNS = ".ec2.internal";
     private static final String PREFIX_PRIVATE_DNS = "mock-ip-";
@@ -91,7 +92,8 @@ protected MockTransportService createTransportService() {
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             writableRegistry(),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public TransportAddress[] addressesFromString(String address) {
@@ -99,7 +101,14 @@ public TransportAddress[] addressesFromString(String address) {
                 return new TransportAddress[] { poorMansDNS.getOrDefault(address, buildNewFakeTransportAddress()) };
             }
         };
-        return new MockTransportService(Settings.EMPTY, transport, threadPool, TransportService.NOOP_TRANSPORT_INTERCEPTOR, null);
+        return new MockTransportService(
+            Settings.EMPTY,
+            transport,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            null,
+            NoopTracer.INSTANCE
+        );
     }
 
     protected List<TransportAddress> buildDynamicHosts(Settings nodeSettings, int nodes) {
@@ -111,7 +120,7 @@ protected List<TransportAddress> buildDynamicHosts(Settings nodeSettings, int no
         try (Ec2DiscoveryPlugin plugin = new Ec2DiscoveryPlugin(buildSettings(accessKey))) {
             AwsEc2SeedHostsProvider provider = new AwsEc2SeedHostsProvider(nodeSettings, transportService, plugin.ec2Service);
             httpServer.createContext("/", exchange -> {
-                if (exchange.getRequestMethod().equals(HttpMethodName.POST.name())) {
+                if (exchange.getRequestMethod().equals("POST")) {
                     final String request = Streams.readFully(exchange.getRequestBody()).toBytesRef().utf8ToString();
                     final String userAgent = exchange.getRequestHeaders().getFirst("User-Agent");
                     if (userAgent != null && userAgent.startsWith("aws-sdk-java")) {
@@ -124,7 +133,7 @@ protected List<TransportAddress> buildDynamicHosts(Settings nodeSettings, int no
                         final String[] params = request.split("&");
                         Arrays.stream(params).filter(entry -> entry.startsWith("Filter.") && entry.contains("=tag%3A")).forEach(entry -> {
                             final int startIndex = "Filter.".length();
-                            final int filterId = Integer.parseInt(entry.substring(startIndex, entry.indexOf(".", startIndex)));
+                            final String filterId = entry.substring(startIndex, entry.indexOf(".", startIndex));
                             tagsIncluded.put(
                                 entry.substring(entry.indexOf("=tag%3A") + "=tag%3A".length()),
                                 Arrays.stream(params)
@@ -135,25 +144,26 @@ protected List<TransportAddress> buildDynamicHosts(Settings nodeSettings, int no
                         });
                         final List<Instance> instances = IntStream.range(1, nodes + 1).mapToObj(node -> {
                             final String instanceId = "node" + node;
-                            final Instance instance = new Instance().withInstanceId(instanceId)
-                                .withState(new InstanceState().withName(InstanceStateName.Running))
-                                .withPrivateDnsName(PREFIX_PRIVATE_DNS + instanceId + SUFFIX_PRIVATE_DNS)
-                                .withPublicDnsName(PREFIX_PUBLIC_DNS + instanceId + SUFFIX_PUBLIC_DNS)
-                                .withPrivateIpAddress(PREFIX_PRIVATE_IP + node)
-                                .withPublicIpAddress(PREFIX_PUBLIC_IP + node);
+                            final Instance.Builder instanceBuilder = Instance.builder()
+                                .instanceId(instanceId)
+                                .state(InstanceState.builder().name(InstanceStateName.RUNNING).build())
+                                .privateDnsName(PREFIX_PRIVATE_DNS + instanceId + SUFFIX_PRIVATE_DNS)
+                                .publicDnsName(PREFIX_PUBLIC_DNS + instanceId + SUFFIX_PUBLIC_DNS)
+                                .privateIpAddress(PREFIX_PRIVATE_IP + node)
+                                .publicIpAddress(PREFIX_PUBLIC_IP + node);
                             if (tagsList != null) {
-                                instance.setTags(tagsList.get(node - 1));
+                                instanceBuilder.tags(tagsList.get(node - 1));
                             }
-                            return instance;
+                            return instanceBuilder.build();
                         })
                             .filter(
                                 instance -> tagsIncluded.entrySet()
                                     .stream()
                                     .allMatch(
-                                        entry -> instance.getTags()
+                                        entry -> instance.tags()
                                             .stream()
-                                            .filter(t -> t.getKey().equals(entry.getKey()))
-                                            .map(Tag::getValue)
+                                            .filter(t -> t.key().equals(entry.getKey()))
+                                            .map(Tag::value)
                                             .collect(Collectors.toList())
                                             .containsAll(entry.getValue())
                                     )
@@ -273,10 +283,10 @@ public void testFilterByTags() throws InterruptedException {
         for (int node = 0; node < nodes; node++) {
             List<Tag> tags = new ArrayList<>();
             if (randomBoolean()) {
-                tags.add(new Tag("stage", "prod"));
+                tags.add(Tag.builder().key("stage").value("prod").build());
                 prodInstances++;
             } else {
-                tags.add(new Tag("stage", "dev"));
+                tags.add(Tag.builder().key("stage").value("dev").build());
             }
             tagsList.add(tags);
         }
@@ -296,15 +306,15 @@ public void testFilterByMultipleTags() throws InterruptedException {
         for (int node = 0; node < nodes; node++) {
             List<Tag> tags = new ArrayList<>();
             if (randomBoolean()) {
-                tags.add(new Tag("stage", "prod"));
+                tags.add(Tag.builder().key("stage").value("prod").build());
                 if (randomBoolean()) {
-                    tags.add(new Tag("stage", "preprod"));
+                    tags.add(Tag.builder().key("stage").value("preprod").build());
                     prodInstances++;
                 }
             } else {
-                tags.add(new Tag("stage", "dev"));
+                tags.add(Tag.builder().key("stage").value("dev").build());
                 if (randomBoolean()) {
-                    tags.add(new Tag("stage", "preprod"));
+                    tags.add(Tag.builder().key("stage").value("preprod").build());
                 }
             }
             tagsList.add(tags);
@@ -331,7 +341,7 @@ public void testReadHostFromTag() throws UnknownHostException {
 
         for (int node = 0; node < nodes; node++) {
             List<Tag> tags = new ArrayList<>();
-            tags.add(new Tag("foo", "node" + (node + 1)));
+            tags.add(Tag.builder().key("foo").value("node" + (node + 1)).build());
             tagsList.add(tags);
         }
 
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2NetworkTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2NetworkTests.java
index f7faf33bf6b30..b4ed613c0d8dd 100644
--- a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2NetworkTests.java
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2NetworkTests.java
@@ -34,13 +34,11 @@
 
 import com.sun.net.httpserver.HttpServer;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.test.OpenSearchTestCase;
-
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
@@ -55,7 +53,6 @@
 import java.util.Collections;
 import java.util.function.BiConsumer;
 
-import static com.amazonaws.SDKGlobalConfiguration.EC2_METADATA_SERVICE_OVERRIDE_SYSTEM_PROPERTY;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.hamcrest.Matchers.arrayContaining;
 import static org.hamcrest.Matchers.equalTo;
@@ -67,7 +64,7 @@
  * They aren't.
  */
 @SuppressForbidden(reason = "use http server")
-public class Ec2NetworkTests extends OpenSearchTestCase {
+public class Ec2NetworkTests extends AbstractEc2DiscoveryTestCase {
 
     private static HttpServer httpServer;
 
@@ -97,7 +94,7 @@ public void setup() {
         // redirect EC2 metadata service to httpServer
         AccessController.doPrivileged(
             (PrivilegedAction<String>) () -> System.setProperty(
-                EC2_METADATA_SERVICE_OVERRIDE_SYSTEM_PROPERTY,
+                "aws.ec2MetadataServiceEndpoint",
                 "http://" + httpServer.getAddress().getHostName() + ":" + httpServer.getAddress().getPort()
             )
         );
@@ -122,7 +119,7 @@ public void testNetworkHostEc2() throws IOException {
     public void testNetworkHostUnableToResolveEc2() {
         // redirect EC2 metadata service to unknown location
         AccessController.doPrivileged(
-            (PrivilegedAction<String>) () -> System.setProperty(EC2_METADATA_SERVICE_OVERRIDE_SYSTEM_PROPERTY, "http://127.0.0.1/")
+            (PrivilegedAction<String>) () -> System.setProperty("aws.ec2MetadataServiceEndpoint", "http://127.0.0.1/")
         );
 
         try {
diff --git a/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2RetriesTests.java b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2RetriesTests.java
new file mode 100644
index 0000000000000..ce097667f9c4b
--- /dev/null
+++ b/plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2RetriesTests.java
@@ -0,0 +1,144 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery.ec2;
+
+import software.amazon.awssdk.services.ec2.model.Instance;
+
+import org.apache.http.HttpStatus;
+import org.apache.http.NameValuePair;
+import org.apache.http.client.utils.URLEncodedUtils;
+import org.opensearch.Version;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.Streams;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.discovery.SeedHostsProvider;
+import org.opensearch.discovery.SeedHostsResolver;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+import org.opensearch.transport.nio.MockNioTransport;
+import org.hamcrest.Matchers;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.hamcrest.Matchers.aMapWithSize;
+import static org.hamcrest.Matchers.is;
+
+@SuppressForbidden(reason = "use a http server")
+public class Ec2RetriesTests extends AbstractEc2MockAPITestCase {
+    @Override
+    protected MockTransportService createTransportService() {
+        return new MockTransportService(
+            Settings.EMPTY,
+            new MockNioTransport(
+                Settings.EMPTY,
+                Version.CURRENT,
+                threadPool,
+                networkService,
+                PageCacheRecycler.NON_RECYCLING_INSTANCE,
+                new NamedWriteableRegistry(Collections.emptyList()),
+                new NoneCircuitBreakerService(),
+                NoopTracer.INSTANCE
+            ),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            null,
+            NoopTracer.INSTANCE
+        );
+    }
+
+    public void testEC2DiscoveryRetriesOnRateLimiting() throws IOException {
+        final String accessKey = "ec2_access";
+        final List<String> hosts = Collections.singletonList("127.0.0.1:9300");
+        final Map<String, Integer> failedRequests = new ConcurrentHashMap<>();
+        // retry the same request 5 times at most
+        final int maxRetries = randomIntBetween(1, 5);
+        httpServer.createContext("/", exchange -> {
+            if (exchange.getRequestMethod().equals("POST")) {
+                final String request = Streams.readFully(exchange.getRequestBody()).utf8ToString();
+                final String userAgent = exchange.getRequestHeaders().getFirst("User-Agent");
+                if (userAgent != null && userAgent.startsWith("aws-sdk-java")) {
+                    final String auth = exchange.getRequestHeaders().getFirst("Authorization");
+                    if (auth == null || auth.contains(accessKey) == false) {
+                        throw new IllegalArgumentException("wrong access key: " + auth);
+                    }
+                    if (failedRequests.compute(
+                        exchange.getRequestHeaders().getFirst("Amz-sdk-invocation-id"),
+                        (requestId, count) -> (count == null ? 0 : count) + 1
+                    ) < maxRetries) {
+                        exchange.sendResponseHeaders(HttpStatus.SC_SERVICE_UNAVAILABLE, -1);
+                        return;
+                    }
+                    // Simulate an EC2 DescribeInstancesResponse
+                    byte[] responseBody = null;
+                    for (NameValuePair parse : URLEncodedUtils.parse(request, UTF_8)) {
+                        if ("Action".equals(parse.getName())) {
+                            responseBody = generateDescribeInstancesResponse(
+                                hosts.stream()
+                                    .map(address -> Instance.builder().publicIpAddress(address).build())
+                                    .collect(Collectors.toList())
+                            );
+                            break;
+                        }
+                    }
+                    responseBody = responseBody == null ? new byte[0] : responseBody;
+                    exchange.getResponseHeaders().set("Content-Type", "text/xml; charset=UTF-8");
+                    exchange.sendResponseHeaders(HttpStatus.SC_OK, responseBody.length);
+                    exchange.getResponseBody().write(responseBody);
+                    return;
+                }
+            }
+            fail("did not send response");
+        });
+        try (Ec2DiscoveryPlugin plugin = new Ec2DiscoveryPlugin(buildSettings(accessKey))) {
+            final SeedHostsProvider seedHostsProvider = plugin.getSeedHostProviders(transportService, networkService).get("ec2").get();
+            final SeedHostsResolver resolver = new SeedHostsResolver("test", Settings.EMPTY, transportService, seedHostsProvider);
+            resolver.start();
+            final List<TransportAddress> addressList = seedHostsProvider.getSeedAddresses(null);
+            assertThat(addressList, Matchers.hasSize(1));
+            assertThat(addressList.get(0).toString(), is(hosts.get(0)));
+            assertThat(failedRequests, aMapWithSize(1));
+            assertThat(failedRequests.values().iterator().next(), is(maxRetries));
+        }
+    }
+}
diff --git a/plugins/discovery-ec2/src/yamlRestTest/resources/rest-api-spec/test/discovery_ec2/10_basic.yml b/plugins/discovery-ec2/src/yamlRestTest/resources/rest-api-spec/test/discovery_ec2/10_basic.yml
index ba51c623fe888..f91565c5d204b 100644
--- a/plugins/discovery-ec2/src/yamlRestTest/resources/rest-api-spec/test/discovery_ec2/10_basic.yml
+++ b/plugins/discovery-ec2/src/yamlRestTest/resources/rest-api-spec/test/discovery_ec2/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: discovery-ec2 } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: discovery-ec2 } }
diff --git a/plugins/discovery-gce/build.gradle b/plugins/discovery-gce/build.gradle
index 2396b228d77a0..beae0d84685a4 100644
--- a/plugins/discovery-gce/build.gradle
+++ b/plugins/discovery-gce/build.gradle
@@ -24,7 +24,7 @@ versions << [
 dependencies {
   api "com.google.apis:google-api-services-compute:v1-rev160-${versions.google}"
   api "com.google.api-client:google-api-client:${versions.google}"
-  api "com.google.oauth-client:google-oauth-client:1.33.1"
+  api "com.google.oauth-client:google-oauth-client:1.33.3"
   api "com.google.http-client:google-http-client:${versions.google}"
   api "com.google.http-client:google-http-client-jackson2:${versions.google}"
   api 'com.google.code.findbugs:jsr305:3.0.2'
@@ -58,13 +58,21 @@ test {
 thirdPartyAudit.ignoreMissingClasses(
   // classes are missing
   'javax.jms.Message',
-  'com.google.common.base.Splitter',
-  'com.google.common.collect.Lists',
   'javax.servlet.ServletContextEvent',
   'javax.servlet.ServletContextListener',
   'org.apache.avalon.framework.logger.Logger',
   'org.apache.log.Hierarchy',
   'org.apache.log.Logger',
+  'com.google.api.client.json.gson.GsonFactory',
+  'com.google.common.base.Preconditions',
+  'com.google.common.base.Splitter',
+  'com.google.common.cache.CacheBuilder',
+  'com.google.common.cache.CacheLoader',
+  'com.google.common.cache.LoadingCache',
+  'com.google.common.collect.ImmutableMap',
+  'com.google.common.collect.ImmutableMap$Builder',
+  'com.google.common.collect.ImmutableSet',
+  'com.google.common.collect.Lists',
   'com.google.common.collect.Multiset',
   'com.google.common.collect.SortedMultiset',
   'com.google.common.collect.TreeMultiset',
diff --git a/plugins/discovery-gce/licenses/commons-codec-1.13.jar.sha1 b/plugins/discovery-gce/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/discovery-gce/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/commons-codec-1.15.jar.sha1 b/plugins/discovery-gce/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/discovery-gce/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/discovery-gce/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index c8756c438320f..0000000000000
--- a/plugins/discovery-gce/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
diff --git a/plugins/discovery-gce/licenses/commons-logging-1.2.jar.sha1 b/plugins/discovery-gce/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/discovery-gce/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/commons-logging-LICENSE.txt b/plugins/discovery-gce/licenses/commons-logging-LICENSE.txt
index d645695673349..57bc88a15a0ee 100644
--- a/plugins/discovery-gce/licenses/commons-logging-LICENSE.txt
+++ b/plugins/discovery-gce/licenses/commons-logging-LICENSE.txt
@@ -1,4 +1,3 @@
-
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -200,3 +199,4 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
+
diff --git a/plugins/discovery-gce/licenses/commons-logging-NOTICE.txt b/plugins/discovery-gce/licenses/commons-logging-NOTICE.txt
index d3d6e140ce4f3..72eb32a902458 100644
--- a/plugins/discovery-gce/licenses/commons-logging-NOTICE.txt
+++ b/plugins/discovery-gce/licenses/commons-logging-NOTICE.txt
@@ -1,5 +1,5 @@
-Apache Commons Logging
-Copyright 2003-2014 The Apache Software Foundation
+Apache Commons CLI
+Copyright 2001-2009 The Apache Software Foundation
 
-This product includes software developed at
+This product includes software developed by
 The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/discovery-gce/licenses/google-oauth-client-1.33.1.jar.sha1 b/plugins/discovery-gce/licenses/google-oauth-client-1.33.1.jar.sha1
deleted file mode 100644
index 3897a85310ec6..0000000000000
--- a/plugins/discovery-gce/licenses/google-oauth-client-1.33.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0a431f1a677c5f89507591ab47a7ccdb0b18b6f7
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/google-oauth-client-1.33.3.jar.sha1 b/plugins/discovery-gce/licenses/google-oauth-client-1.33.3.jar.sha1
new file mode 100644
index 0000000000000..f2afaa1bc2dba
--- /dev/null
+++ b/plugins/discovery-gce/licenses/google-oauth-client-1.33.3.jar.sha1
@@ -0,0 +1 @@
+9d445a8649b0de731922b9a3ebf1552b5403611d
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/httpclient-4.5.13.jar.sha1 b/plugins/discovery-gce/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/plugins/discovery-gce/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/httpclient-4.5.14.jar.sha1 b/plugins/discovery-gce/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/plugins/discovery-gce/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/httpcore-4.4.12.jar.sha1 b/plugins/discovery-gce/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/plugins/discovery-gce/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/httpcore-4.4.16.jar.sha1 b/plugins/discovery-gce/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/plugins/discovery-gce/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/log4j-1.2-api-2.17.1.jar.sha1 b/plugins/discovery-gce/licenses/log4j-1.2-api-2.17.1.jar.sha1
deleted file mode 100644
index 23aa5c60bd596..0000000000000
--- a/plugins/discovery-gce/licenses/log4j-1.2-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-db3a7e7f07e878b92ac4a8f1100bee8325d5713a
\ No newline at end of file
diff --git a/plugins/discovery-gce/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/discovery-gce/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/discovery-gce/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEDiscoveryClientYamlTestSuiteIT.java b/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEDiscoveryClientYamlTestSuiteIT.java
index 8b05c700a9650..adb7c46665560 100644
--- a/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEDiscoveryClientYamlTestSuiteIT.java
+++ b/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEDiscoveryClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEFixture.java b/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEFixture.java
index f1eba6a635504..f5a231ef869f5 100644
--- a/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEFixture.java
+++ b/plugins/discovery-gce/qa/gce/src/yamlRestTest/java/org/opensearch/cloud/gce/GCEFixture.java
@@ -32,12 +32,10 @@
 package org.opensearch.cloud.gce;
 
 import org.apache.http.client.methods.HttpGet;
-
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.path.PathTrie;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 import org.opensearch.test.fixture.AbstractHttpFixture;
 
@@ -139,13 +137,12 @@ private PathTrie<RequestHandler> defaultHandlers() {
         handlers.insert(
             nonAuthPath(HttpGet.METHOD_NAME, "/computeMetadata/v1/instance/service-accounts/default/token"),
             request -> jsonValue.apply(
-                Strings.toString(
-                    jsonBuilder().startObject()
-                        .field("access_token", TOKEN)
-                        .field("expires_in", TimeUnit.HOURS.toSeconds(1))
-                        .field("token_type", TOKEN_TYPE)
-                        .endObject()
-                )
+                jsonBuilder().startObject()
+                    .field("access_token", TOKEN)
+                    .field("expires_in", TimeUnit.HOURS.toSeconds(1))
+                    .field("token_type", TOKEN_TYPE)
+                    .endObject()
+                    .toString()
             )
         );
 
@@ -179,9 +176,7 @@ private PathTrie<RequestHandler> defaultHandlers() {
                 );
             }
 
-            final String json = Strings.toString(
-                jsonBuilder().startObject().field("id", "test-instances").field("items", items).endObject()
-            );
+            final String json = jsonBuilder().startObject().field("id", "test-instances").field("items", items).endObject().toString();
 
             final byte[] responseAsBytes = json.getBytes(StandardCharsets.UTF_8);
             final Map<String, String> headers = new HashMap<>(JSON_CONTENT_TYPE);
@@ -213,29 +208,28 @@ protected Response handle(final Request request) throws IOException {
     }
 
     private static Response newError(final RestStatus status, final String code, final String message) throws IOException {
-        final String response = Strings.toString(
-            jsonBuilder().startObject()
-                .field(
-                    "error",
-                    MapBuilder.<String, Object>newMapBuilder()
-                        .put(
-                            "errors",
-                            Collections.singletonList(
-                                MapBuilder.<String, Object>newMapBuilder()
-                                    .put("domain", "global")
-                                    .put("reason", "required")
-                                    .put("message", message)
-                                    .put("locationType", "header")
-                                    .put("location", code)
-                                    .immutableMap()
-                            )
+        final String response = jsonBuilder().startObject()
+            .field(
+                "error",
+                MapBuilder.<String, Object>newMapBuilder()
+                    .put(
+                        "errors",
+                        Collections.singletonList(
+                            MapBuilder.<String, Object>newMapBuilder()
+                                .put("domain", "global")
+                                .put("reason", "required")
+                                .put("message", message)
+                                .put("locationType", "header")
+                                .put("location", code)
+                                .immutableMap()
                         )
-                        .put("code", status.getStatus())
-                        .put("message", message)
-                        .immutableMap()
-                )
-                .endObject()
-        );
+                    )
+                    .put("code", status.getStatus())
+                    .put("message", message)
+                    .immutableMap()
+            )
+            .endObject()
+            .toString();
 
         return new Response(status.getStatus(), JSON_CONTENT_TYPE, response.getBytes(UTF_8));
     }
diff --git a/plugins/discovery-gce/src/internalClusterTest/java/org/opensearch/discovery/gce/GceDiscoverTests.java b/plugins/discovery-gce/src/internalClusterTest/java/org/opensearch/discovery/gce/GceDiscoverTests.java
index 815537b534586..e97a4650ca8ae 100644
--- a/plugins/discovery-gce/src/internalClusterTest/java/org/opensearch/discovery/gce/GceDiscoverTests.java
+++ b/plugins/discovery-gce/src/internalClusterTest/java/org/opensearch/discovery/gce/GceDiscoverTests.java
@@ -35,7 +35,6 @@
 import com.google.api.services.compute.model.Instance;
 import com.google.api.services.compute.model.NetworkInterface;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
-
 import org.opensearch.cloud.gce.GceInstancesService;
 import org.opensearch.cloud.gce.util.Access;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -44,7 +43,6 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.transport.TransportService;
-
 import org.junit.After;
 
 import java.io.IOException;
@@ -85,18 +83,18 @@ protected Settings nodeSettings(int nodeOrdinal) {
     }
 
     public void testJoin() {
-        // start master node
-        final String masterNode = internalCluster().startMasterOnlyNode();
-        registerGceNode(masterNode);
+        // start cluster-manager node
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        registerGceNode(clusterManagerNode);
 
-        ClusterStateResponse clusterStateResponse = client(masterNode).admin()
+        ClusterStateResponse clusterStateResponse = client(clusterManagerNode).admin()
             .cluster()
             .prepareState()
-            .setMasterNodeTimeout("1s")
+            .setClusterManagerNodeTimeout("1s")
             .clear()
             .setNodes(true)
             .get();
-        assertNotNull(clusterStateResponse.getState().nodes().getMasterNodeId());
+        assertNotNull(clusterStateResponse.getState().nodes().getClusterManagerNodeId());
 
         // start another node
         final String secondNode = internalCluster().startNode();
@@ -104,12 +102,12 @@ public void testJoin() {
         clusterStateResponse = client(secondNode).admin()
             .cluster()
             .prepareState()
-            .setMasterNodeTimeout("1s")
+            .setClusterManagerNodeTimeout("1s")
             .clear()
             .setNodes(true)
             .setLocal(true)
             .get();
-        assertNotNull(clusterStateResponse.getState().nodes().getMasterNodeId());
+        assertNotNull(clusterStateResponse.getState().nodes().getClusterManagerNodeId());
 
         // wait for the cluster to form
         assertNoTimeout(client().admin().cluster().prepareHealth().setWaitForNodes(Integer.toString(2)).get());
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceInstancesServiceImpl.java b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceInstancesServiceImpl.java
index f25faaf415140..46cc1c8eab537 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceInstancesServiceImpl.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceInstancesServiceImpl.java
@@ -46,7 +46,6 @@
 import com.google.api.services.compute.Compute;
 import com.google.api.services.compute.model.Instance;
 import com.google.api.services.compute.model.InstanceList;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceMetadataService.java b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceMetadataService.java
index 4873cb6dcbf7a..ef73f741ad20c 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceMetadataService.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/GceMetadataService.java
@@ -32,12 +32,6 @@
 
 package org.opensearch.cloud.gce;
 
-import java.io.IOException;
-import java.net.URI;
-import java.net.URISyntaxException;
-import java.security.GeneralSecurityException;
-import java.util.function.Function;
-
 import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
 import com.google.api.client.http.GenericUrl;
 import com.google.api.client.http.HttpHeaders;
@@ -46,10 +40,16 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cloud.gce.util.Access;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.GeneralSecurityException;
+import java.util.function.Function;
+
 public class GceMetadataService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(GceMetadataService.class);
 
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/network/GceNameResolver.java b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/network/GceNameResolver.java
index 7482dfac401ef..28e41963de489 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/network/GceNameResolver.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/cloud/gce/network/GceNameResolver.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cloud.gce.GceMetadataService;
 import org.opensearch.cloud.gce.util.Access;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.NetworkService.CustomNameResolver;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 import java.net.InetAddress;
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/GceSeedHostsProvider.java b/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/GceSeedHostsProvider.java
index 19247a7bb536d..5958c07e244ad 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/GceSeedHostsProvider.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/GceSeedHostsProvider.java
@@ -35,20 +35,19 @@
 import com.google.api.services.compute.model.AccessConfig;
 import com.google.api.services.compute.model.Instance;
 import com.google.api.services.compute.model.NetworkInterface;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
 import org.opensearch.cloud.gce.GceInstancesService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.transport.TransportService;
 
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/RetryHttpInitializerWrapper.java b/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/RetryHttpInitializerWrapper.java
index 26b8215bed7ff..6e5372cad0a4b 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/RetryHttpInitializerWrapper.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/discovery/gce/RetryHttpInitializerWrapper.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.discovery.gce;
 
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.LogManager;
 import com.google.api.client.auth.oauth2.Credential;
 import com.google.api.client.googleapis.testing.auth.oauth2.MockGoogleCredential;
 import com.google.api.client.http.HttpBackOffIOExceptionHandler;
@@ -44,6 +42,8 @@
 import com.google.api.client.http.HttpUnsuccessfulResponseHandler;
 import com.google.api.client.util.ExponentialBackOff;
 import com.google.api.client.util.Sleeper;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.cloud.gce.util.Access;
 import org.opensearch.common.unit.TimeValue;
 
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java b/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
index 6d015f54ffb29..d4df6d94c061b 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
@@ -36,17 +36,17 @@
 import com.google.api.client.util.ClassInfo;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.cloud.gce.GceInstancesService;
 import org.opensearch.cloud.gce.GceInstancesServiceImpl;
 import org.opensearch.cloud.gce.GceMetadataService;
 import org.opensearch.cloud.gce.network.GceNameResolver;
 import org.opensearch.cloud.gce.util.Access;
 import org.opensearch.common.Booleans;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.discovery.gce.GceSeedHostsProvider;
 import org.opensearch.plugins.DiscoveryPlugin;
diff --git a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceDiscoveryTests.java b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceDiscoveryTests.java
index 2ca1234bb8a04..b4af9773f33de 100644
--- a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceDiscoveryTests.java
+++ b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceDiscoveryTests.java
@@ -37,7 +37,8 @@
 import org.opensearch.cloud.gce.GceMetadataService;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -109,7 +110,7 @@ public void setProjectName() {
 
     @Before
     public void createTransportService() {
-        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null);
+        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, NoopTracer.INSTANCE);
     }
 
     @After
diff --git a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceMockUtils.java b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceMockUtils.java
index 5109600be7488..f39ab200da8ed 100644
--- a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceMockUtils.java
+++ b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceMockUtils.java
@@ -41,9 +41,9 @@
 import com.google.api.client.testing.http.MockLowLevelHttpResponse;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.io.Streams;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.util.FileSystemUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceNetworkTests.java b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceNetworkTests.java
index a1d7613bf2ba4..091a4f720d258 100644
--- a/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceNetworkTests.java
+++ b/plugins/discovery-gce/src/test/java/org/opensearch/discovery/gce/GceNetworkTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.discovery.gce;
 
 import org.opensearch.cloud.gce.network.GceNameResolver;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/attributes/google-compute-default-zone b/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/attributes/google-compute-default-zone
index 6cf886270bef1..218127ccfb695 100644
--- a/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/attributes/google-compute-default-zone
+++ b/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/attributes/google-compute-default-zone
@@ -1 +1 @@
-europe-west1-b
\ No newline at end of file
+europe-west1-b
diff --git a/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/project-id b/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/project-id
index 25b8069381897..44be476f3ae83 100644
--- a/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/project-id
+++ b/plugins/discovery-gce/src/test/resources/org/opensearch/discovery/gce/computeMetadata/v1/project/project-id
@@ -1 +1 @@
-metadataserver
\ No newline at end of file
+metadataserver
diff --git a/plugins/discovery-gce/src/yamlRestTest/resources/rest-api-spec/test/discovery_gce/10_basic.yml b/plugins/discovery-gce/src/yamlRestTest/resources/rest-api-spec/test/discovery_gce/10_basic.yml
index a5379c2c68bed..828e006ae822d 100644
--- a/plugins/discovery-gce/src/yamlRestTest/resources/rest-api-spec/test/discovery_gce/10_basic.yml
+++ b/plugins/discovery-gce/src/yamlRestTest/resources/rest-api-spec/test/discovery_gce/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: discovery-gce } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: discovery-gce } }
diff --git a/plugins/examples/build.gradle b/plugins/examples/build.gradle
index e4e0ca6f7be99..4a6228b227f95 100644
--- a/plugins/examples/build.gradle
+++ b/plugins/examples/build.gradle
@@ -31,9 +31,8 @@ gradle.projectsEvaluated {
 configure(project('painless-whitelist')) {
   configurations.all {
     resolutionStrategy.dependencySubstitution {
-      substitute module('org.opensearch.plugin:opensearch-scripting-painless-spi') with project(':modules:lang-painless:spi')
-      substitute module('org.opensearch.test:logger-usage') with project(':test:logger-usage')
+      substitute module('org.opensearch.plugin:opensearch-scripting-painless-spi') using project(':modules:lang-painless:spi')
+      substitute module('org.opensearch.test:logger-usage') using project(':test:logger-usage')
     }
   }
 }
-
diff --git a/plugins/examples/custom-settings/build.gradle b/plugins/examples/custom-settings/build.gradle
index 104660c458991..5b35d887b3db1 100644
--- a/plugins/examples/custom-settings/build.gradle
+++ b/plugins/examples/custom-settings/build.gradle
@@ -42,4 +42,3 @@ testClusters.all {
   // Adds a setting in the OpenSearch keystore before running the integration tests
   keystore 'custom.secured', 'password'
 }
-
diff --git a/plugins/examples/custom-settings/src/main/config/custom.yml b/plugins/examples/custom-settings/src/main/config/custom.yml
index 1759e0ff96d40..258e050a0664b 100644
--- a/plugins/examples/custom-settings/src/main/config/custom.yml
+++ b/plugins/examples/custom-settings/src/main/config/custom.yml
@@ -2,4 +2,4 @@
 custom:
     simple: foo
     list: [0, 1, 1, 2, 3, 5, 8, 13, 21]
-    filtered: secret
\ No newline at end of file
+    filtered: secret
diff --git a/plugins/examples/custom-settings/src/main/java/org/opensearch/example/customsettings/ExampleCustomSettingsConfig.java b/plugins/examples/custom-settings/src/main/java/org/opensearch/example/customsettings/ExampleCustomSettingsConfig.java
index 5f494147c870f..b373d602d6e04 100644
--- a/plugins/examples/custom-settings/src/main/java/org/opensearch/example/customsettings/ExampleCustomSettingsConfig.java
+++ b/plugins/examples/custom-settings/src/main/java/org/opensearch/example/customsettings/ExampleCustomSettingsConfig.java
@@ -33,10 +33,10 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 
 import java.io.IOException;
diff --git a/plugins/examples/custom-settings/src/yamlRestTest/java/org/opensearch/example/customsettings/ExampleCustomSettingsClientYamlTestSuiteIT.java b/plugins/examples/custom-settings/src/yamlRestTest/java/org/opensearch/example/customsettings/ExampleCustomSettingsClientYamlTestSuiteIT.java
index 2e6da40553401..2f163aa5aabf5 100644
--- a/plugins/examples/custom-settings/src/yamlRestTest/java/org/opensearch/example/customsettings/ExampleCustomSettingsClientYamlTestSuiteIT.java
+++ b/plugins/examples/custom-settings/src/yamlRestTest/java/org/opensearch/example/customsettings/ExampleCustomSettingsClientYamlTestSuiteIT.java
@@ -33,6 +33,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/custom-significance-heuristic/src/main/java/org/opensearch/example/customsigheuristic/SimpleHeuristic.java b/plugins/examples/custom-significance-heuristic/src/main/java/org/opensearch/example/customsigheuristic/SimpleHeuristic.java
index 8365a56bcfe4e..8320c274f3023 100644
--- a/plugins/examples/custom-significance-heuristic/src/main/java/org/opensearch/example/customsigheuristic/SimpleHeuristic.java
+++ b/plugins/examples/custom-significance-heuristic/src/main/java/org/opensearch/example/customsigheuristic/SimpleHeuristic.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.example.customsigheuristic;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 
 import java.io.IOException;
diff --git a/plugins/examples/custom-significance-heuristic/src/test/java/org/opensearch/example/customsigheuristic/SimpleHeuristicWireTests.java b/plugins/examples/custom-significance-heuristic/src/test/java/org/opensearch/example/customsigheuristic/SimpleHeuristicWireTests.java
index 197b8be9c5536..fb93fc3bc49c8 100644
--- a/plugins/examples/custom-significance-heuristic/src/test/java/org/opensearch/example/customsigheuristic/SimpleHeuristicWireTests.java
+++ b/plugins/examples/custom-significance-heuristic/src/test/java/org/opensearch/example/customsigheuristic/SimpleHeuristicWireTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.example.customsigheuristic;
 
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/plugins/examples/custom-significance-heuristic/src/yamlRestTest/java/org/opensearch/example/customsigheuristic/CustomSignificanceHeuristicClientYamlTestSuiteIT.java b/plugins/examples/custom-significance-heuristic/src/yamlRestTest/java/org/opensearch/example/customsigheuristic/CustomSignificanceHeuristicClientYamlTestSuiteIT.java
index 881905fbceade..69ba949f60271 100644
--- a/plugins/examples/custom-significance-heuristic/src/yamlRestTest/java/org/opensearch/example/customsigheuristic/CustomSignificanceHeuristicClientYamlTestSuiteIT.java
+++ b/plugins/examples/custom-significance-heuristic/src/yamlRestTest/java/org/opensearch/example/customsigheuristic/CustomSignificanceHeuristicClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/custom-significance-heuristic/src/yamlRestTest/resources/rest-api-spec/test/custom-significance-heuristic/10_basic.yml b/plugins/examples/custom-significance-heuristic/src/yamlRestTest/resources/rest-api-spec/test/custom-significance-heuristic/10_basic.yml
index 620aa393a6b5b..5cd56683f427d 100644
--- a/plugins/examples/custom-significance-heuristic/src/yamlRestTest/resources/rest-api-spec/test/custom-significance-heuristic/10_basic.yml
+++ b/plugins/examples/custom-significance-heuristic/src/yamlRestTest/resources/rest-api-spec/test/custom-significance-heuristic/10_basic.yml
@@ -5,12 +5,12 @@
         reason: "contains is a newly added assertion"
         features: contains
 
-    # Get master node id
+    # Get cluster-manager node id
     - do:
         cluster.state: {}
-    - set: { master_node: master }
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains: { nodes.$master.plugins: { name: custom-significance-heuristic } }
+    - contains: { nodes.$cluster_manager.plugins: { name: custom-significance-heuristic } }
diff --git a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggester.java b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggester.java
index da154609e5f2f..23166135b829b 100644
--- a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggester.java
+++ b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggester.java
@@ -34,7 +34,7 @@
 
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggester;
 
diff --git a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestion.java b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestion.java
index 50ee700c3a253..34d3aec2c3d9f 100644
--- a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestion.java
+++ b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestion.java
@@ -32,19 +32,19 @@
 
 package org.opensearch.example.customsuggester;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.Suggest;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 public class CustomSuggestion extends Suggest.Suggestion<CustomSuggestion.Entry> {
 
diff --git a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestionBuilder.java b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestionBuilder.java
index a7551fca3cf24..2a75bbcf7dbf4 100644
--- a/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestionBuilder.java
+++ b/plugins/examples/custom-suggester/src/main/java/org/opensearch/example/customsuggester/CustomSuggestionBuilder.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.example.customsuggester;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.suggest.SuggestionBuilder;
 import org.opensearch.search.suggest.SuggestionSearchContext;
diff --git a/plugins/examples/custom-suggester/src/yamlRestTest/java/org/opensearch/example/customsuggester/CustomSuggesterClientYamlTestSuiteIT.java b/plugins/examples/custom-suggester/src/yamlRestTest/java/org/opensearch/example/customsuggester/CustomSuggesterClientYamlTestSuiteIT.java
index b6237a7a9f855..b924a003c4e1d 100644
--- a/plugins/examples/custom-suggester/src/yamlRestTest/java/org/opensearch/example/customsuggester/CustomSuggesterClientYamlTestSuiteIT.java
+++ b/plugins/examples/custom-suggester/src/yamlRestTest/java/org/opensearch/example/customsuggester/CustomSuggesterClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/custom-suggester/src/yamlRestTest/resources/rest-api-spec/test/custom-suggester/10_basic.yml b/plugins/examples/custom-suggester/src/yamlRestTest/resources/rest-api-spec/test/custom-suggester/10_basic.yml
index ed8d0f78a092b..0ef1d4a0679d7 100644
--- a/plugins/examples/custom-suggester/src/yamlRestTest/resources/rest-api-spec/test/custom-suggester/10_basic.yml
+++ b/plugins/examples/custom-suggester/src/yamlRestTest/resources/rest-api-spec/test/custom-suggester/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: custom-suggester } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: custom-suggester } }
diff --git a/plugins/examples/painless-whitelist/src/yamlRestTest/java/org/opensearch/example/painlesswhitelist/PainlessWhitelistClientYamlTestSuiteIT.java b/plugins/examples/painless-whitelist/src/yamlRestTest/java/org/opensearch/example/painlesswhitelist/PainlessWhitelistClientYamlTestSuiteIT.java
index 63214ad3de67c..a1f38e091ec75 100644
--- a/plugins/examples/painless-whitelist/src/yamlRestTest/java/org/opensearch/example/painlesswhitelist/PainlessWhitelistClientYamlTestSuiteIT.java
+++ b/plugins/examples/painless-whitelist/src/yamlRestTest/java/org/opensearch/example/painlesswhitelist/PainlessWhitelistClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/painless-whitelist/src/yamlRestTest/resources/rest-api-spec/test/painless_whitelist/10_basic.yml b/plugins/examples/painless-whitelist/src/yamlRestTest/resources/rest-api-spec/test/painless_whitelist/10_basic.yml
index cc3762eb42d68..fab9789eeec10 100644
--- a/plugins/examples/painless-whitelist/src/yamlRestTest/resources/rest-api-spec/test/painless_whitelist/10_basic.yml
+++ b/plugins/examples/painless-whitelist/src/yamlRestTest/resources/rest-api-spec/test/painless_whitelist/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: painless-whitelist } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: painless-whitelist } }
diff --git a/plugins/examples/rescore/src/main/java/org/opensearch/example/rescore/ExampleRescoreBuilder.java b/plugins/examples/rescore/src/main/java/org/opensearch/example/rescore/ExampleRescoreBuilder.java
index 724f9f6743624..f0a1fc9511de6 100644
--- a/plugins/examples/rescore/src/main/java/org/opensearch/example/rescore/ExampleRescoreBuilder.java
+++ b/plugins/examples/rescore/src/main/java/org/opensearch/example/rescore/ExampleRescoreBuilder.java
@@ -38,15 +38,15 @@
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TopDocs;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.LeafNumericFieldData;
-import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -60,23 +60,38 @@
 import java.util.Objects;
 
 import static java.util.Collections.singletonList;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Example rescorer that multiplies the score of the hit by some factor and doesn't resort them.
  */
 public class ExampleRescoreBuilder extends RescorerBuilder<ExampleRescoreBuilder> {
+    /**
+     * The name of this builder.
+     */
     public static final String NAME = "example";
 
     private final float factor;
     private final String factorField;
 
+    /**
+     * Instantiate this builder with a weighting factor and optional field.
+     *
+     * @param factor The weighting factor.
+     * @param factorField An optional field.
+     */
     public ExampleRescoreBuilder(float factor, @Nullable String factorField) {
         this.factor = factor;
         this.factorField = factorField;
     }
 
+    /**
+     * Instantiate this object from a stream.
+     *
+     * @param in Input to read the value from
+     * @throws IOException on failure to read the value.
+     */
     ExampleRescoreBuilder(StreamInput in) throws IOException {
         super(in);
         factor = in.readFloat();
@@ -119,6 +134,11 @@ protected void doXContent(XContentBuilder builder, Params params) throws IOExcep
         PARSER.declareString(optionalConstructorArg(), FACTOR_FIELD);
     }
 
+    /**
+     * Instantiate an ExampleRescoreBuilder from XContent.
+     *
+     * @param parser The XContent parser to use
+     */
     public static ExampleRescoreBuilder fromXContent(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
diff --git a/plugins/examples/rescore/src/test/java/org/opensearch/example/rescore/ExampleRescoreBuilderTests.java b/plugins/examples/rescore/src/test/java/org/opensearch/example/rescore/ExampleRescoreBuilderTests.java
index 53bd89999f990..88f845d86f4aa 100644
--- a/plugins/examples/rescore/src/test/java/org/opensearch/example/rescore/ExampleRescoreBuilderTests.java
+++ b/plugins/examples/rescore/src/test/java/org/opensearch/example/rescore/ExampleRescoreBuilderTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/plugins/examples/rescore/src/yamlRestTest/java/org/opensearch/example/rescore/ExampleRescoreClientYamlTestSuiteIT.java b/plugins/examples/rescore/src/yamlRestTest/java/org/opensearch/example/rescore/ExampleRescoreClientYamlTestSuiteIT.java
index aec77cffdc9e9..7e870c7d5cb97 100644
--- a/plugins/examples/rescore/src/yamlRestTest/java/org/opensearch/example/rescore/ExampleRescoreClientYamlTestSuiteIT.java
+++ b/plugins/examples/rescore/src/yamlRestTest/java/org/opensearch/example/rescore/ExampleRescoreClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/rescore/src/yamlRestTest/resources/rest-api-spec/test/example-rescore/10_basic.yml b/plugins/examples/rescore/src/yamlRestTest/resources/rest-api-spec/test/example-rescore/10_basic.yml
index f0d0bcb35fad9..00c5977529c6c 100644
--- a/plugins/examples/rescore/src/yamlRestTest/resources/rest-api-spec/test/example-rescore/10_basic.yml
+++ b/plugins/examples/rescore/src/yamlRestTest/resources/rest-api-spec/test/example-rescore/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: example-rescore } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: example-rescore } }
diff --git a/plugins/examples/rest-handler/build.gradle b/plugins/examples/rest-handler/build.gradle
index cc939b15854d5..b97d091af9d08 100644
--- a/plugins/examples/rest-handler/build.gradle
+++ b/plugins/examples/rest-handler/build.gradle
@@ -56,4 +56,3 @@ javaRestTest {
   dependsOn exampleFixture
   nonInputProperties.systemProperty 'external.address', "${-> exampleFixture.addressAndPort}"
 }
-
diff --git a/plugins/examples/rest-handler/src/yamlRestTest/java/org/opensearch/example/resthandler/ExampleRestHandlerClientYamlTestSuiteIT.java b/plugins/examples/rest-handler/src/yamlRestTest/java/org/opensearch/example/resthandler/ExampleRestHandlerClientYamlTestSuiteIT.java
index 4fe87c089d09f..6e374ec7e70db 100644
--- a/plugins/examples/rest-handler/src/yamlRestTest/java/org/opensearch/example/resthandler/ExampleRestHandlerClientYamlTestSuiteIT.java
+++ b/plugins/examples/rest-handler/src/yamlRestTest/java/org/opensearch/example/resthandler/ExampleRestHandlerClientYamlTestSuiteIT.java
@@ -33,6 +33,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/script-expert-scoring/build.gradle b/plugins/examples/script-expert-scoring/build.gradle
index 9f2bab20a7db0..e4ddd97abbe4c 100644
--- a/plugins/examples/script-expert-scoring/build.gradle
+++ b/plugins/examples/script-expert-scoring/build.gradle
@@ -39,4 +39,3 @@ opensearchplugin {
 }
 
 test.enabled = false
-
diff --git a/plugins/examples/script-expert-scoring/src/main/java/org/opensearch/example/expertscript/ExpertScriptPlugin.java b/plugins/examples/script-expert-scoring/src/main/java/org/opensearch/example/expertscript/ExpertScriptPlugin.java
index 819176e3e1cb0..074ecc3942d38 100644
--- a/plugins/examples/script-expert-scoring/src/main/java/org/opensearch/example/expertscript/ExpertScriptPlugin.java
+++ b/plugins/examples/script-expert-scoring/src/main/java/org/opensearch/example/expertscript/ExpertScriptPlugin.java
@@ -35,6 +35,7 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.IndexSearcher;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ScriptPlugin;
@@ -115,20 +116,22 @@ public boolean isResultDeterministic() {
             @Override
             public LeafFactory newFactory(
                 Map<String, Object> params,
-                SearchLookup lookup
+                SearchLookup lookup,
+                IndexSearcher indexSearcher
             ) {
-                return new PureDfLeafFactory(params, lookup);
+                return new PureDfLeafFactory(params, lookup, indexSearcher);
             }
         }
 
         private static class PureDfLeafFactory implements LeafFactory {
             private final Map<String, Object> params;
             private final SearchLookup lookup;
+            private final IndexSearcher indexSearcher;
             private final String field;
             private final String term;
 
             private PureDfLeafFactory(
-                        Map<String, Object> params, SearchLookup lookup) {
+                        Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher) {
                 if (params.containsKey("field") == false) {
                     throw new IllegalArgumentException(
                             "Missing parameter [field]");
@@ -139,6 +142,7 @@ private PureDfLeafFactory(
                 }
                 this.params = params;
                 this.lookup = lookup;
+                this.indexSearcher = indexSearcher;
                 field = params.get("field").toString();
                 term = params.get("term").toString();
             }
@@ -158,7 +162,7 @@ public ScoreScript newInstance(LeafReaderContext context)
                      * the field and/or term don't exist in this segment,
                      * so always return 0
                      */
-                    return new ScoreScript(params, lookup, context) {
+                    return new ScoreScript(params, lookup, indexSearcher, context) {
                         @Override
                         public double execute(
                             ExplanationHolder explanation
@@ -167,7 +171,7 @@ public double execute(
                         }
                     };
                 }
-                return new ScoreScript(params, lookup, context) {
+                return new ScoreScript(params, lookup, indexSearcher, context) {
                     int currentDocid = -1;
                     @Override
                     public void setDocument(int docid) {
diff --git a/plugins/examples/script-expert-scoring/src/yamlRestTest/java/org/opensearch/example/expertscript/ExpertScriptClientYamlTestSuiteIT.java b/plugins/examples/script-expert-scoring/src/yamlRestTest/java/org/opensearch/example/expertscript/ExpertScriptClientYamlTestSuiteIT.java
index 294b1de4e7f99..b104f612c35c0 100644
--- a/plugins/examples/script-expert-scoring/src/yamlRestTest/java/org/opensearch/example/expertscript/ExpertScriptClientYamlTestSuiteIT.java
+++ b/plugins/examples/script-expert-scoring/src/yamlRestTest/java/org/opensearch/example/expertscript/ExpertScriptClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/examples/script-expert-scoring/src/yamlRestTest/resources/rest-api-spec/test/script_expert_scoring/10_basic.yml b/plugins/examples/script-expert-scoring/src/yamlRestTest/resources/rest-api-spec/test/script_expert_scoring/10_basic.yml
index 70842d5e767e5..d65943f0201b3 100644
--- a/plugins/examples/script-expert-scoring/src/yamlRestTest/resources/rest-api-spec/test/script_expert_scoring/10_basic.yml
+++ b/plugins/examples/script-expert-scoring/src/yamlRestTest/resources/rest-api-spec/test/script_expert_scoring/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: script-expert-scoring } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: script-expert-scoring } }
diff --git a/plugins/identity-shiro/build.gradle b/plugins/identity-shiro/build.gradle
new file mode 100644
index 0000000000000..baa3464d0a98e
--- /dev/null
+++ b/plugins/identity-shiro/build.gradle
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+apply plugin: 'opensearch.internal-cluster-test'
+
+opensearchplugin {
+  description 'Plugin for identity features in OpenSearch.'
+  classname 'org.opensearch.identity.shiro.ShiroIdentityPlugin'
+  name project.name
+  licenseFile rootProject.file('licenses/APACHE-LICENSE-2.0.txt')
+  noticeFile rootProject.file('NOTICE.txt')
+}
+
+dependencies {
+  implementation 'org.apache.shiro:shiro-core:1.11.0'
+
+  // Needed for shiro
+  implementation "org.slf4j:slf4j-api:${versions.slf4j}"
+
+  implementation 'commons-beanutils:commons-beanutils:1.9.4'
+  implementation 'commons-logging:commons-logging:1.2'
+  implementation 'commons-lang:commons-lang:2.6'
+
+  implementation 'org.passay:passay:1.6.3'
+
+  implementation "org.bouncycastle:bcprov-jdk15to18:${versions.bouncycastle}"
+
+  testImplementation project(path: ':modules:transport-netty4') // for http
+  testImplementation project(path: ':plugins:transport-nio') // for http
+  testImplementation "org.mockito:mockito-core:${versions.mockito}"
+  testImplementation project(path: ':client:rest-high-level')
+  testImplementation 'junit:junit:4.13.2'
+}
+
+/*
+ * We have to disable setting the number of available processors as tests in the same JVM randomize processors and will step on each
+ * other if we allow them to set the number of available processors as it's set-once in Netty.
+ */
+test {
+  systemProperty 'opensearch.set.netty.runtime.available.processors', 'false'
+}
+
+internalClusterTest {
+  systemProperty 'opensearch.set.netty.runtime.available.processors', 'false'
+}
+
+thirdPartyAudit.ignoreMissingClasses(
+  'com.google.common.hash.BloomFilter',
+  'javax.servlet.ServletContextEvent',
+  'javax.servlet.ServletContextListener',
+  'org.apache.avalon.framework.logger.Logger',
+  'org.apache.commons.collections.Closure',
+  'org.apache.commons.collections.FastHashMap',
+  'org.apache.commons.collections.Predicate',
+  'org.apache.commons.collections.Transformer',
+  'org.apache.commons.collections.comparators.ComparableComparator',
+  'org.apache.commons.collections.keyvalue.AbstractMapEntry',
+  'org.apache.commons.configuration2.interpol.ConfigurationInterpolator',
+  'org.apache.log.Hierarchy',
+  'org.apache.log.Logger',
+  'org.apache.log4j.Level',
+  'org.apache.log4j.Logger',
+  'org.apache.log4j.Priority',
+  'org.cryptacular.bean.HashBean',
+  'org.slf4j.impl.StaticLoggerBinder',
+  'org.slf4j.impl.StaticMDCBinder',
+  'org.slf4j.impl.StaticMarkerBinder',
+  'org.springframework.context.MessageSource',
+  'org.springframework.context.support.MessageSourceAccessor'
+)
diff --git a/plugins/identity-shiro/licenses/bcprov-jdk15to18-1.76.jar.sha1 b/plugins/identity-shiro/licenses/bcprov-jdk15to18-1.76.jar.sha1
new file mode 100644
index 0000000000000..2e96c404bef98
--- /dev/null
+++ b/plugins/identity-shiro/licenses/bcprov-jdk15to18-1.76.jar.sha1
@@ -0,0 +1 @@
+0cb53f10290a634808555bc4b34328fdab1001f2
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/bcprov-jdk15to18-LICENSE.txt b/plugins/identity-shiro/licenses/bcprov-jdk15to18-LICENSE.txt
new file mode 100644
index 0000000000000..9f27bafe96885
--- /dev/null
+++ b/plugins/identity-shiro/licenses/bcprov-jdk15to18-LICENSE.txt
@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2000 - 2013 The Legion of the Bouncy Castle Inc.
+                          (http://www.bouncycastle.org)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/plugins/identity-shiro/licenses/bcprov-jdk15to18-NOTICE.txt b/plugins/identity-shiro/licenses/bcprov-jdk15to18-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/identity-shiro/licenses/commons-beanutils-1.9.4.jar.sha1 b/plugins/identity-shiro/licenses/commons-beanutils-1.9.4.jar.sha1
new file mode 100644
index 0000000000000..b91aa1e1d1f4f
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-beanutils-1.9.4.jar.sha1
@@ -0,0 +1 @@
+d52b9abcd97f38c81342bb7e7ae1eee9b73cba51
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/commons-beanutils-LICENSE.txt b/plugins/identity-shiro/licenses/commons-beanutils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-beanutils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/identity-shiro/licenses/commons-beanutils-NOTICE.txt b/plugins/identity-shiro/licenses/commons-beanutils-NOTICE.txt
new file mode 100644
index 0000000000000..e1529d40c6bb6
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-beanutils-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache Commons BeanUtils
+Copyright 2000-2019 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/identity-shiro/licenses/commons-lang-2.6.jar.sha1 b/plugins/identity-shiro/licenses/commons-lang-2.6.jar.sha1
new file mode 100644
index 0000000000000..4ee9249d2b76f
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-lang-2.6.jar.sha1
@@ -0,0 +1 @@
+0ce1edb914c94ebc388f086c6827e8bdeec71ac2
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/commons-lang-LICENSE.txt b/plugins/identity-shiro/licenses/commons-lang-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-lang-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/identity-shiro/licenses/commons-lang-NOTICE.txt b/plugins/identity-shiro/licenses/commons-lang-NOTICE.txt
new file mode 100644
index 0000000000000..780ac0edb3c94
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-lang-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache Commons Lang
+Copyright 2001-2022 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (https://www.apache.org/).
diff --git a/plugins/identity-shiro/licenses/commons-logging-1.2.jar.sha1 b/plugins/identity-shiro/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/commons-logging-LICENSE.txt b/plugins/identity-shiro/licenses/commons-logging-LICENSE.txt
new file mode 100644
index 0000000000000..57bc88a15a0ee
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-logging-LICENSE.txt
@@ -0,0 +1,202 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
diff --git a/plugins/identity-shiro/licenses/commons-logging-NOTICE.txt b/plugins/identity-shiro/licenses/commons-logging-NOTICE.txt
new file mode 100644
index 0000000000000..72eb32a902458
--- /dev/null
+++ b/plugins/identity-shiro/licenses/commons-logging-NOTICE.txt
@@ -0,0 +1,5 @@
+Apache Commons CLI
+Copyright 2001-2009 The Apache Software Foundation
+
+This product includes software developed by
+The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/identity-shiro/licenses/passay-1.6.3.jar.sha1 b/plugins/identity-shiro/licenses/passay-1.6.3.jar.sha1
new file mode 100644
index 0000000000000..52ac0b1a81469
--- /dev/null
+++ b/plugins/identity-shiro/licenses/passay-1.6.3.jar.sha1
@@ -0,0 +1 @@
+bae4754c87297f5600e4071b2596c0b6625cf92b
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/passay-LICENSE.txt b/plugins/identity-shiro/licenses/passay-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/identity-shiro/licenses/passay-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/identity-shiro/licenses/passay-NOTICE.txt b/plugins/identity-shiro/licenses/passay-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/identity-shiro/licenses/shiro-core-1.11.0.jar.sha1 b/plugins/identity-shiro/licenses/shiro-core-1.11.0.jar.sha1
new file mode 100644
index 0000000000000..67c33e15ec689
--- /dev/null
+++ b/plugins/identity-shiro/licenses/shiro-core-1.11.0.jar.sha1
@@ -0,0 +1 @@
+033a70c87e91968a299f1ee00f4e95050312346d
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/shiro-core-LICENSE.txt b/plugins/identity-shiro/licenses/shiro-core-LICENSE.txt
new file mode 100644
index 0000000000000..261eeb9e9f8b2
--- /dev/null
+++ b/plugins/identity-shiro/licenses/shiro-core-LICENSE.txt
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/identity-shiro/licenses/shiro-core-NOTICE.txt b/plugins/identity-shiro/licenses/shiro-core-NOTICE.txt
new file mode 100644
index 0000000000000..1a356397fa88c
--- /dev/null
+++ b/plugins/identity-shiro/licenses/shiro-core-NOTICE.txt
@@ -0,0 +1,15 @@
+Apache Shiro
+Copyright 2008-2022 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+
+The implementation for org.apache.shiro.util.SoftHashMap is based
+on initial ideas from Dr. Heinz Kabutz's publicly posted version
+available at http://www.javaspecialists.eu/archive/Issue015.html,
+with continued modifications.
+
+Certain parts (StringUtils, IpAddressMatcher, AntPathMatcherTests, etc.) of the
+source code for this product was copied for simplicity and to reduce
+dependencies from the source code developed by the Spring Framework Project
+(http://www.springframework.org).
diff --git a/plugins/identity-shiro/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/identity-shiro/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/identity-shiro/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/identity-shiro/licenses/slf4j-api-LICENSE.txt b/plugins/identity-shiro/licenses/slf4j-api-LICENSE.txt
new file mode 100644
index 0000000000000..8fda22f4d72f6
--- /dev/null
+++ b/plugins/identity-shiro/licenses/slf4j-api-LICENSE.txt
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2014 QOS.ch
+All rights reserved.
+
+Permission is hereby granted, free  of charge, to any person obtaining
+a  copy  of this  software  and  associated  documentation files  (the
+"Software"), to  deal in  the Software without  restriction, including
+without limitation  the rights to  use, copy, modify,  merge, publish,
+distribute,  sublicense, and/or sell  copies of  the Software,  and to
+permit persons to whom the Software  is furnished to do so, subject to
+the following conditions:
+
+The  above  copyright  notice  and  this permission  notice  shall  be
+included in all copies or substantial portions of the Software.
+
+THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
+EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
+MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/plugins/identity-shiro/licenses/slf4j-api-NOTICE.txt b/plugins/identity-shiro/licenses/slf4j-api-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroIdentityPlugin.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroIdentityPlugin.java
new file mode 100644
index 0000000000000..77cab13880c27
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroIdentityPlugin.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.shiro.SecurityUtils;
+import org.apache.shiro.mgt.SecurityManager;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.TokenManager;
+import org.opensearch.plugins.IdentityPlugin;
+import org.opensearch.plugins.Plugin;
+
+/**
+ * Identity implementation with Shiro
+ *
+ * @opensearch.experimental
+ */
+public final class ShiroIdentityPlugin extends Plugin implements IdentityPlugin {
+    private Logger log = LogManager.getLogger(this.getClass());
+
+    private final Settings settings;
+    private final ShiroTokenManager authTokenHandler;
+
+    /**
+     * Create a new instance of the Shiro Identity Plugin
+     *
+     * @param settings settings being used in the configuration
+     */
+    public ShiroIdentityPlugin(final Settings settings) {
+        this.settings = settings;
+        authTokenHandler = new ShiroTokenManager();
+
+        SecurityManager securityManager = new ShiroSecurityManager();
+        SecurityUtils.setSecurityManager(securityManager);
+    }
+
+    /**
+     * Return a Shiro Subject based on the provided authTokenHandler and current subject
+     *
+     * @return The current subject
+     */
+    @Override
+    public Subject getSubject() {
+        return new ShiroSubject(authTokenHandler, SecurityUtils.getSubject());
+    }
+
+    /**
+     * Return the Shiro Token Handler
+     *
+     * @return the Shiro Token Handler
+     */
+    @Override
+    public TokenManager getTokenManager() {
+        return this.authTokenHandler;
+    }
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSecurityManager.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSecurityManager.java
new file mode 100644
index 0000000000000..96cf05ac53a1a
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSecurityManager.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.apache.shiro.mgt.DefaultSecurityManager;
+import org.apache.shiro.mgt.DefaultSessionStorageEvaluator;
+import org.apache.shiro.mgt.DefaultSubjectDAO;
+import org.opensearch.identity.shiro.realm.OpenSearchRealm;
+
+/**
+ * OpenSearch specific security manager implementation
+ *
+ * @opensearch.experimental
+ */
+public class ShiroSecurityManager extends DefaultSecurityManager {
+
+    /**
+     * Creates the security manager using a default realm and no session storage
+     */
+    public ShiroSecurityManager() {
+        super(OpenSearchRealm.INSTANCE);
+
+        // By default shiro stores session information into a cache, there were performance
+        // issues with this sessions cache and so are defaulting to a stateless configuration
+        final DefaultSessionStorageEvaluator evaluator = new DefaultSessionStorageEvaluator();
+        evaluator.setSessionStorageEnabled(false);
+
+        final DefaultSubjectDAO subjectDAO = new DefaultSubjectDAO();
+        subjectDAO.setSessionStorageEvaluator(evaluator);
+        setSubjectDAO(subjectDAO);
+    }
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSubject.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSubject.java
new file mode 100644
index 0000000000000..e55204593621c
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroSubject.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.AuthToken;
+
+import java.security.Principal;
+import java.util.Objects;
+
+/**
+ * Subject backed by Shiro
+ *
+ * @opensearch.experimental
+ */
+public class ShiroSubject implements Subject {
+    private final ShiroTokenManager authTokenHandler;
+    private final org.apache.shiro.subject.Subject shiroSubject;
+
+    /**
+     * Creates a new shiro subject for use with the IdentityPlugin
+     * Cannot return null
+     * @param authTokenHandler Used to extract auth header info
+     * @param subject The specific subject being authc/z'd
+     */
+    public ShiroSubject(final ShiroTokenManager authTokenHandler, final org.apache.shiro.subject.Subject subject) {
+        this.authTokenHandler = Objects.requireNonNull(authTokenHandler);
+        this.shiroSubject = Objects.requireNonNull(subject);
+    }
+
+    /**
+     * Return the current principal
+     *
+     * @return The current principal
+     */
+    @Override
+    public Principal getPrincipal() {
+        final Object o = shiroSubject.getPrincipal();
+        if (o == null) return null;
+        if (o instanceof Principal) return (Principal) o;
+        return () -> o.toString();
+    }
+
+    /**
+     * Check if another object is equal to this object
+     *
+     * @param obj The object to be compared against this
+     * @return Whether the two objects are equal
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        final Subject that = (Subject) obj;
+        return Objects.equals(getPrincipal(), that.getPrincipal());
+    }
+
+    /**
+     * Return this Subject's principal as a hash
+     * @return An int hash code
+     */
+    @Override
+    public int hashCode() {
+        return Objects.hash(getPrincipal());
+    }
+
+    /**
+     * Convert this ShiroSubject's principal to a string
+     * @return A string of the subject's principal
+     */
+    @Override
+    public String toString() {
+        return "ShiroSubject(principal=" + getPrincipal() + ")";
+    }
+
+    /**
+     * Logs the user in via authenticating the user against current Shiro realm
+     * @param authenticationToken The authToken to be used for login
+     */
+    public void authenticate(AuthToken authenticationToken) {
+        final org.apache.shiro.authc.AuthenticationToken authToken = authTokenHandler.translateAuthToken(authenticationToken)
+            .orElseThrow(() -> new UnsupportedAuthenticationToken());
+        shiroSubject.login(authToken);
+    }
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroTokenManager.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroTokenManager.java
new file mode 100644
index 0000000000000..345b98d5cb423
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/ShiroTokenManager.java
@@ -0,0 +1,138 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.shiro.SecurityUtils;
+import org.apache.shiro.authc.AuthenticationToken;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.opensearch.common.Randomness;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.identity.tokens.AuthToken;
+import org.opensearch.identity.tokens.BasicAuthToken;
+import org.opensearch.identity.tokens.TokenManager;
+
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Random;
+
+import org.passay.CharacterRule;
+import org.passay.EnglishCharacterData;
+import org.passay.PasswordGenerator;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+/**
+ * Extracts Shiro's {@link AuthenticationToken} from different types of auth headers
+ *
+ * @opensearch.experimental
+ */
+class ShiroTokenManager implements TokenManager {
+
+    private static final Logger log = LogManager.getLogger(IdentityService.class);
+
+    private static Map<BasicAuthToken, String> shiroTokenPasswordMap = new HashMap<>();
+
+    /**
+     * Translates into shiro auth token from the given header token
+     * @param authenticationToken the token from which to translate
+     * @return An optional of the shiro auth token for login
+     */
+    public Optional<AuthenticationToken> translateAuthToken(org.opensearch.identity.tokens.AuthToken authenticationToken) {
+        if (authenticationToken instanceof BasicAuthToken) {
+            final BasicAuthToken basicAuthToken = (BasicAuthToken) authenticationToken;
+            return Optional.of(new UsernamePasswordToken(basicAuthToken.getUser(), basicAuthToken.getPassword()));
+        }
+
+        return Optional.empty();
+    }
+
+    @Override
+    public AuthToken issueToken(String audience) {
+
+        String password = generatePassword();
+        final byte[] rawEncoded = Base64.getEncoder().encode((audience + ":" + password).getBytes(UTF_8));
+        final String usernamePassword = new String(rawEncoded, UTF_8);
+        final String header = "Basic " + usernamePassword;
+        BasicAuthToken token = new BasicAuthToken(header);
+        shiroTokenPasswordMap.put(token, password);
+
+        return token;
+    }
+
+    public boolean validateToken(AuthToken token) {
+        if (token instanceof BasicAuthToken) {
+            final BasicAuthToken basicAuthToken = (BasicAuthToken) token;
+            return basicAuthToken.getUser().equals(SecurityUtils.getSubject().toString())
+                && basicAuthToken.getPassword().equals(shiroTokenPasswordMap.get(basicAuthToken));
+        }
+        return false;
+    }
+
+    public String getTokenInfo(AuthToken token) {
+        if (token instanceof BasicAuthToken) {
+            final BasicAuthToken basicAuthToken = (BasicAuthToken) token;
+            return basicAuthToken.toString();
+        }
+        throw new UnsupportedAuthenticationToken();
+    }
+
+    public void revokeToken(AuthToken token) {
+        if (token instanceof BasicAuthToken) {
+            final BasicAuthToken basicAuthToken = (BasicAuthToken) token;
+            basicAuthToken.revoke();
+            return;
+        }
+        throw new UnsupportedAuthenticationToken();
+    }
+
+    public void resetToken(AuthToken token) {
+        if (token instanceof BasicAuthToken) {
+            final BasicAuthToken basicAuthToken = (BasicAuthToken) token;
+            basicAuthToken.revoke();
+        }
+    }
+
+    /**
+     * When the ShiroTokenManager is in use, a random password is generated for each token and is then output to the logs.
+     * The password is used for development only.
+     * @return A randomly generated password for development
+     */
+    public String generatePassword() {
+
+        CharacterRule lowercaseCharacterRule = new CharacterRule(EnglishCharacterData.LowerCase, 1);
+        CharacterRule uppercaseCharacterRule = new CharacterRule(EnglishCharacterData.UpperCase, 1);
+        CharacterRule numericCharacterRule = new CharacterRule(EnglishCharacterData.Digit, 1);
+        CharacterRule specialCharacterRule = new CharacterRule(EnglishCharacterData.Special, 1);
+
+        List<CharacterRule> rules = Arrays.asList(
+            lowercaseCharacterRule,
+            uppercaseCharacterRule,
+            numericCharacterRule,
+            specialCharacterRule
+        );
+        PasswordGenerator passwordGenerator = new PasswordGenerator();
+
+        Random random = Randomness.get();
+
+        String password = passwordGenerator.generatePassword(random.nextInt(8) + 8, rules); // Generate a 8 to 16 char password
+        log.info("Generated password: " + password);
+        return password;
+    }
+
+    Map<BasicAuthToken, String> getShiroTokenPasswordMap() {
+        return shiroTokenPasswordMap;
+    }
+
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/UnsupportedAuthenticationToken.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/UnsupportedAuthenticationToken.java
new file mode 100644
index 0000000000000..f216bbfefe940
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/UnsupportedAuthenticationToken.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+/** Thrown if the authentication token was invalid */
+public class UnsupportedAuthenticationToken extends RuntimeException {}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/package-info.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/package-info.java
new file mode 100644
index 0000000000000..49e276f11f660
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Identity implementation using Shiro
+ */
+package org.opensearch.identity.shiro;
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcher.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcher.java
new file mode 100644
index 0000000000000..a2cb78425929e
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcher.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro.realm;
+
+import org.apache.shiro.authc.AuthenticationInfo;
+import org.apache.shiro.authc.AuthenticationToken;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.apache.shiro.authc.credential.CredentialsMatcher;
+import org.bouncycastle.crypto.generators.OpenBSDBCrypt;
+
+/**
+ * Password matcher for BCrypt
+ *
+ * @opensearch.experimental
+ */
+public class BCryptPasswordMatcher implements CredentialsMatcher {
+
+    /**
+     * Check if the provided authentication token and authentication info match one another
+     * @param token   the {@code AuthenticationToken} submitted during the authentication attempt
+     * @param info the {@code AuthenticationInfo} stored in the system.
+     * @return A boolean showing whether the token credentials match the info or not.
+     */
+    @Override
+    public boolean doCredentialsMatch(AuthenticationToken token, AuthenticationInfo info) {
+        final UsernamePasswordToken userToken = (UsernamePasswordToken) token;
+        return OpenBSDBCrypt.checkPassword((String) info.getCredentials(), userToken.getPassword());
+    }
+
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/OpenSearchRealm.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/OpenSearchRealm.java
new file mode 100644
index 0000000000000..ef405a5637ae7
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/OpenSearchRealm.java
@@ -0,0 +1,142 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro.realm;
+
+import org.apache.shiro.authc.AuthenticationException;
+import org.apache.shiro.authc.AuthenticationInfo;
+import org.apache.shiro.authc.AuthenticationToken;
+import org.apache.shiro.authc.IncorrectCredentialsException;
+import org.apache.shiro.authc.SimpleAuthenticationInfo;
+import org.apache.shiro.authc.UnknownAccountException;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.apache.shiro.authc.pam.UnsupportedTokenException;
+import org.apache.shiro.realm.AuthenticatingRealm;
+import org.opensearch.identity.NamedPrincipal;
+
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Internal Realm is a custom realm using the internal OpenSearch IdP
+ *
+ * @opensearch.experimental
+ */
+public class OpenSearchRealm extends AuthenticatingRealm {
+    private static final String DEFAULT_REALM_NAME = "internal";
+
+    /**
+     * The instance of the realm to be constructed through the builder method
+     */
+    public static final OpenSearchRealm INSTANCE = new OpenSearchRealm.Builder(DEFAULT_REALM_NAME).build();
+
+    private final String realmName;
+
+    private Map<String, User> internalUsers;
+
+    /**
+     * Instantiate a new OpenSearchRealm
+     *
+     * @param realmName The name of the realm
+     * @param internalUsers A map of internal users
+     */
+    private OpenSearchRealm(final String realmName, final Map<String, User> internalUsers) {
+        super(new BCryptPasswordMatcher());
+        this.realmName = realmName;
+        this.internalUsers = internalUsers;
+        setAuthenticationTokenClass(UsernamePasswordToken.class);
+    }
+
+    /**
+     * An internal class representing a realm builder
+     *
+     */
+    public static final class Builder {
+        private final String name;
+
+        /**
+         *  Instantiate a realm builder
+         * @param name The name of the realm builder
+         */
+        public Builder(final String name) {
+            this.name = Objects.requireNonNull(name);
+        }
+
+        /**
+         * Create a new OpenSearchRealm
+         *
+         * @return A new realm
+         */
+        public OpenSearchRealm build() {
+            // TODO: Replace hardcoded admin user / user map with an external provider
+            final User adminUser = new User();
+            adminUser.setUsername(new NamedPrincipal("admin"));
+            adminUser.setBcryptHash("$2a$12$VcCDgh2NDk07JGN0rjGbM.Ad41qVR/YFJcgHp0UGns5JDymv..TOG"); // Password 'admin'
+            final Map<String, User> internalUsers = Map.of("admin", adminUser);
+            return new OpenSearchRealm(name, internalUsers);
+        }
+    }
+
+    /**
+     * Return an internal user given a principalIdentifier
+     *
+     * @param principalIdentifier The string of the identifier
+     * @return The associated user
+     * @throws UnknownAccountException when the principal identifier has no user match
+     */
+    public User getInternalUser(final String principalIdentifier) throws UnknownAccountException {
+        final User userRecord = internalUsers.get(principalIdentifier);
+        if (userRecord == null) {
+            throw new UnknownAccountException();
+        }
+        return userRecord;
+    }
+
+    /**
+     * Gets the authentication info associated with a specific authentication token
+     *
+     * @param token the authentication token containing the user's principal and credentials.
+     * @return Authentication info associated with the auth token
+     * @throws AuthenticationException When the auth token has no valid info
+     */
+    @Override
+    protected AuthenticationInfo doGetAuthenticationInfo(final AuthenticationToken token) throws AuthenticationException {
+        if (token instanceof UsernamePasswordToken) {
+            final String username = ((UsernamePasswordToken) token).getUsername();
+            // Look up the user by the provide username
+            final User userRecord = getInternalUser(username);
+            // TODO: Check for other things, like a locked account, expired password, etc.
+
+            // Verify the user
+            final SimpleAuthenticationInfo sai = new SimpleAuthenticationInfo(
+                userRecord.getUsername(),
+                userRecord.getBcryptHash(),
+                realmName
+            );
+
+            final boolean successfulAuthentication = getCredentialsMatcher().doCredentialsMatch(token, sai);
+
+            if (successfulAuthentication) {
+                // TODO: Check for anything else that might prevent login (expired password, locked account, etc.)
+                // if (other problems) {
+                // throw new CredentialsException(); // Or something more specific
+                // }
+                // Success!
+                return sai;
+            } else {
+                // Bad password
+                throw new IncorrectCredentialsException();
+            }
+        }
+
+        // If the token was not handled, it was unsupported
+        final String tokenClassName = Optional.ofNullable(token).map(Object::getClass).map(Class::getName).orElse("null");
+        throw new UnsupportedTokenException("Unable to support authentication token " + tokenClassName);
+    }
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/User.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/User.java
new file mode 100644
index 0000000000000..35b3348a955d7
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/User.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro.realm;
+
+import org.opensearch.identity.NamedPrincipal;
+
+/**
+ * A non-volatile and immutable object in the storage.
+ *
+ * @opensearch.experimental
+ */
+public class User {
+
+    private NamedPrincipal username;
+    private String bcryptHash;
+
+    /**
+     * Get the User's username as a NamedPrincipal
+     * @return the named principal representing the username
+     */
+    public NamedPrincipal getUsername() {
+        return username;
+    }
+
+    /**
+     * Set the User's username
+     * @param username NamedPrincipal representing the username to be set
+     */
+    public void setUsername(NamedPrincipal username) {
+        this.username = username;
+    }
+
+    /**
+     * Get the User's hash
+     * @return The User's hash as a string
+     */
+    public String getBcryptHash() {
+        return bcryptHash;
+    }
+
+    /**
+     * Set the User's hash
+     * @param bcryptHash A string to be set as the User's hash
+     */
+    public void setBcryptHash(String bcryptHash) {
+        this.bcryptHash = bcryptHash;
+    }
+}
diff --git a/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/package-info.java b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/package-info.java
new file mode 100644
index 0000000000000..888f54c6e37ea
--- /dev/null
+++ b/plugins/identity-shiro/src/main/java/org/opensearch/identity/shiro/realm/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for the internal OpenSearch realm */
+package org.opensearch.identity.shiro.realm;
diff --git a/plugins/identity-shiro/src/main/plugin-metadata/plugin-security.policy b/plugins/identity-shiro/src/main/plugin-metadata/plugin-security.policy
new file mode 100644
index 0000000000000..120d1d8fbdb3a
--- /dev/null
+++ b/plugins/identity-shiro/src/main/plugin-metadata/plugin-security.policy
@@ -0,0 +1,11 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+grant {
+
+};
diff --git a/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/AuthTokenHandlerTests.java b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/AuthTokenHandlerTests.java
new file mode 100644
index 0000000000000..24a06bd9ac71a
--- /dev/null
+++ b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/AuthTokenHandlerTests.java
@@ -0,0 +1,150 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.apache.shiro.authc.AuthenticationToken;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.opensearch.identity.noop.NoopTokenManager;
+import org.opensearch.identity.tokens.AuthToken;
+import org.opensearch.identity.tokens.BasicAuthToken;
+import org.opensearch.identity.tokens.BearerAuthToken;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.Optional;
+
+import org.passay.CharacterCharacteristicsRule;
+import org.passay.CharacterRule;
+import org.passay.EnglishCharacterData;
+import org.passay.LengthRule;
+import org.passay.PasswordData;
+import org.passay.PasswordValidator;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+
+public class AuthTokenHandlerTests extends OpenSearchTestCase {
+
+    private ShiroTokenManager shiroAuthTokenHandler;
+    private NoopTokenManager noopTokenManager;
+
+    @Before
+    public void testSetup() {
+        shiroAuthTokenHandler = new ShiroTokenManager();
+        noopTokenManager = new NoopTokenManager();
+    }
+
+    public void testShouldExtractBasicAuthTokenSuccessfully() {
+        final BasicAuthToken authToken = new BasicAuthToken("Basic YWRtaW46YWRtaW4="); // admin:admin
+
+        final AuthenticationToken translatedToken = shiroAuthTokenHandler.translateAuthToken(authToken).get();
+        assertThat(translatedToken, is(instanceOf(UsernamePasswordToken.class)));
+
+        final UsernamePasswordToken usernamePasswordToken = (UsernamePasswordToken) translatedToken;
+        assertThat(usernamePasswordToken, notNullValue());
+        assertThat(usernamePasswordToken.getUsername(), equalTo("admin"));
+        assertThat(new String(usernamePasswordToken.getPassword()), equalTo("admin"));
+    }
+
+    public void testShouldExtractBasicAuthTokenSuccessfully_twoSemiColonPassword() {
+        final BasicAuthToken authToken = new BasicAuthToken("Basic dGVzdDp0ZTpzdA=="); // test:te:st
+
+        final AuthenticationToken translatedToken = shiroAuthTokenHandler.translateAuthToken(authToken).get();
+        assertThat(translatedToken, is(instanceOf(UsernamePasswordToken.class)));
+
+        final UsernamePasswordToken usernamePasswordToken = (UsernamePasswordToken) translatedToken;
+        assertThat(usernamePasswordToken, notNullValue());
+        assertThat(usernamePasswordToken.getUsername(), equalTo("test"));
+        assertThat(new String(usernamePasswordToken.getPassword()), equalTo("te:st"));
+    }
+
+    public void testShouldReturnNullWhenExtractingNullToken() {
+        final Optional<AuthenticationToken> translatedToken = shiroAuthTokenHandler.translateAuthToken(null);
+
+        assertThat(translatedToken.isEmpty(), is(true));
+    }
+
+    public void testShouldRevokeTokenSuccessfully() {
+        final BasicAuthToken authToken = new BasicAuthToken("Basic dGVzdDp0ZTpzdA==");
+        assertTrue(authToken.toString().equals("Basic auth token with user=test, password=te:st"));
+        shiroAuthTokenHandler.revokeToken(authToken);
+        assert (authToken.toString().equals("Basic auth token with user=, password="));
+    }
+
+    public void testShouldResetTokenSuccessfully() {
+        final BasicAuthToken authToken = new BasicAuthToken("Basic dGVzdDp0ZTpzdA==");
+        assertTrue(authToken.toString().equals("Basic auth token with user=test, password=te:st"));
+        shiroAuthTokenHandler.resetToken(authToken);
+        assert (authToken.toString().equals("Basic auth token with user=, password="));
+    }
+
+    public void testShouldFailWhenRevokeToken() {
+        final BearerAuthToken bearerAuthToken = new BearerAuthToken("header.payload.signature");
+        assert (bearerAuthToken.getTokenIdentifier().equals("Bearer"));
+        assertThrows(UnsupportedAuthenticationToken.class, () -> shiroAuthTokenHandler.revokeToken(bearerAuthToken));
+    }
+
+    public void testShouldFailGetTokenInfo() {
+        final BearerAuthToken bearerAuthToken = new BearerAuthToken("header.payload.signature");
+        assert (bearerAuthToken.getTokenIdentifier().equals("Bearer"));
+        assertThrows(UnsupportedAuthenticationToken.class, () -> shiroAuthTokenHandler.getTokenInfo(bearerAuthToken));
+    }
+
+    public void testShouldFailValidateToken() {
+        final BearerAuthToken bearerAuthToken = new BearerAuthToken("header.payload.signature");
+        assertFalse(shiroAuthTokenHandler.validateToken(bearerAuthToken));
+    }
+
+    public void testShoudPassMapLookupWithToken() {
+        final BasicAuthToken authToken = new BasicAuthToken("Basic dGVzdDp0ZTpzdA==");
+        shiroAuthTokenHandler.getShiroTokenPasswordMap().put(authToken, "te:st");
+        assertTrue(authToken.getPassword().equals(shiroAuthTokenHandler.getShiroTokenPasswordMap().get(authToken)));
+    }
+
+    public void testShouldPassThrougbResetToken(AuthToken token) {
+        final BearerAuthToken bearerAuthToken = new BearerAuthToken("header.payload.signature");
+        shiroAuthTokenHandler.resetToken(bearerAuthToken);
+    }
+
+    public void testVerifyBearerTokenObject() {
+        BearerAuthToken testGoodToken = new BearerAuthToken("header.payload.signature");
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> new BearerAuthToken("asddfhadfasdfad"));
+        assert (exception.getMessage().contains("Illegally formed bearer authorization token "));
+        assertEquals(testGoodToken.getCompleteToken(), "header.payload.signature");
+        assertEquals(testGoodToken.getTokenIdentifier(), "Bearer");
+        assertEquals(testGoodToken.getHeader(), "header");
+        assertEquals(testGoodToken.getPayload(), "payload");
+        assertEquals(testGoodToken.getSignature(), "signature");
+        assertEquals(testGoodToken.toString(), "Bearer auth token with header=header, payload=payload, signature=signature");
+    }
+
+    public void testGeneratedPasswordContents() {
+        String password = shiroAuthTokenHandler.generatePassword();
+        PasswordData data = new PasswordData(password);
+
+        LengthRule lengthRule = new LengthRule(8, 16);
+
+        CharacterCharacteristicsRule characteristicsRule = new CharacterCharacteristicsRule();
+
+        // Define M (3 in this case)
+        characteristicsRule.setNumberOfCharacteristics(3);
+
+        // Define elements of N (upper, lower, digit, symbol)
+        characteristicsRule.getRules().add(new CharacterRule(EnglishCharacterData.UpperCase, 1));
+        characteristicsRule.getRules().add(new CharacterRule(EnglishCharacterData.LowerCase, 1));
+        characteristicsRule.getRules().add(new CharacterRule(EnglishCharacterData.Digit, 1));
+        characteristicsRule.getRules().add(new CharacterRule(EnglishCharacterData.Special, 1));
+
+        PasswordValidator validator = new PasswordValidator(lengthRule, characteristicsRule);
+        validator.validate(data);
+    }
+
+}
diff --git a/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroIdentityPluginTests.java b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroIdentityPluginTests.java
new file mode 100644
index 0000000000000..626cd44d13ec8
--- /dev/null
+++ b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroIdentityPluginTests.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.plugins.IdentityPlugin;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThrows;
+
+public class ShiroIdentityPluginTests extends OpenSearchTestCase {
+
+    public void testSingleIdentityPluginSucceeds() {
+        IdentityPlugin identityPlugin1 = new ShiroIdentityPlugin(Settings.EMPTY);
+        List<IdentityPlugin> pluginList1 = List.of(identityPlugin1);
+        IdentityService identityService1 = new IdentityService(Settings.EMPTY, pluginList1);
+        assertThat(identityService1.getTokenManager(), is(instanceOf(ShiroTokenManager.class)));
+    }
+
+    public void testMultipleIdentityPluginsFail() {
+        IdentityPlugin identityPlugin1 = new ShiroIdentityPlugin(Settings.EMPTY);
+        IdentityPlugin identityPlugin2 = new ShiroIdentityPlugin(Settings.EMPTY);
+        IdentityPlugin identityPlugin3 = new ShiroIdentityPlugin(Settings.EMPTY);
+        List<IdentityPlugin> pluginList = List.of(identityPlugin1, identityPlugin2, identityPlugin3);
+        Exception ex = assertThrows(OpenSearchException.class, () -> new IdentityService(Settings.EMPTY, pluginList));
+        assert (ex.getMessage().contains("Multiple identity plugins are not supported,"));
+    }
+
+}
diff --git a/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroSubjectTests.java b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroSubjectTests.java
new file mode 100644
index 0000000000000..ca896e1475120
--- /dev/null
+++ b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/ShiroSubjectTests.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro;
+
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.security.Principal;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+public class ShiroSubjectTests extends OpenSearchTestCase {
+
+    private org.apache.shiro.subject.Subject shiroSubject;
+    private ShiroTokenManager authTokenHandler;
+    private ShiroSubject subject;
+
+    @Before
+    public void setup() {
+        shiroSubject = mock(org.apache.shiro.subject.Subject.class);
+        authTokenHandler = mock(ShiroTokenManager.class);
+        subject = new ShiroSubject(authTokenHandler, shiroSubject);
+    }
+
+    @After
+    public void cleanup() {
+        verifyNoMoreInteractions(shiroSubject);
+    }
+
+    public void testGetPrincipal_null() {
+        when(shiroSubject.getPrincipal()).thenReturn(null);
+
+        final Principal result = subject.getPrincipal();
+
+        assertThat(result, nullValue());
+        verify(shiroSubject).getPrincipal();
+    }
+
+    public void testGetPrincipal_principal() {
+        final Principal mockPrincipal = mock(Principal.class);
+        when(shiroSubject.getPrincipal()).thenReturn(mockPrincipal);
+
+        final Principal result = subject.getPrincipal();
+
+        assertThat(result, equalTo(mockPrincipal));
+        verify(shiroSubject).getPrincipal();
+    }
+
+    public void testGetPrincipal_otherType() {
+        final Object objPrincipal = mock(Object.class);
+        when(shiroSubject.getPrincipal()).thenReturn(objPrincipal);
+        when(objPrincipal.toString()).thenReturn("objectPrincipalString");
+
+        final Principal result = subject.getPrincipal();
+
+        // assertThat(result, equalTo("objectPrincipalString"));
+        verify(shiroSubject).getPrincipal();
+        verifyNoMoreInteractions(objPrincipal);
+    }
+
+}
diff --git a/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcherTests.java b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcherTests.java
new file mode 100644
index 0000000000000..91e88ed1bf701
--- /dev/null
+++ b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/BCryptPasswordMatcherTests.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro.realm;
+
+import org.apache.shiro.authc.AuthenticationInfo;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class BCryptPasswordMatcherTests extends OpenSearchTestCase {
+
+    public void testCredentialMatch() {
+        final UsernamePasswordToken token = mock(UsernamePasswordToken.class);
+        when(token.getPassword()).thenReturn("admin".toCharArray());
+        final AuthenticationInfo info = mock(AuthenticationInfo.class);
+        when(info.getCredentials()).thenReturn("$2a$12$VcCDgh2NDk07JGN0rjGbM.Ad41qVR/YFJcgHp0UGns5JDymv..TOG");
+
+        final BCryptPasswordMatcher matcher = new BCryptPasswordMatcher();
+        final boolean result = matcher.doCredentialsMatch(token, info);
+
+        assertThat(result, equalTo(true));
+    }
+
+    public void testCredentialDoNotMatch() {
+        final UsernamePasswordToken token = mock(UsernamePasswordToken.class);
+        when(token.getPassword()).thenReturn("HashedPassword".toCharArray());
+        final AuthenticationInfo info = mock(AuthenticationInfo.class);
+        when(info.getCredentials()).thenReturn("$2a$12$VcCDgh2NDk07JGN0rQGbM.Ad41qVR/YFJcgHp0UGns5JDymv..TOG");
+
+        final BCryptPasswordMatcher matcher = new BCryptPasswordMatcher();
+        final boolean result = matcher.doCredentialsMatch(token, info);
+
+        assertThat(result, equalTo(false));
+    }
+}
diff --git a/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/OpenSearchRealmTests.java b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/OpenSearchRealmTests.java
new file mode 100644
index 0000000000000..db96a6d91a38e
--- /dev/null
+++ b/plugins/identity-shiro/src/test/java/org/opensearch/identity/shiro/realm/OpenSearchRealmTests.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.shiro.realm;
+
+import org.apache.shiro.authc.AuthenticationInfo;
+import org.apache.shiro.authc.IncorrectCredentialsException;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+public class OpenSearchRealmTests extends OpenSearchTestCase {
+
+    private OpenSearchRealm realm;
+
+    @Before
+    public void setup() {
+        realm = new OpenSearchRealm.Builder("test").build();
+    }
+
+    public void testGetAuthenticationInfoUserExists() {
+        final UsernamePasswordToken token = new UsernamePasswordToken("admin", "admin");
+        final User admin = realm.getInternalUser("admin");
+        final AuthenticationInfo adminInfo = realm.getAuthenticationInfo(token);
+        assertNotNull(adminInfo);
+    }
+
+    public void testGetAuthenticationInfoUserExistsWrongPassword() {
+        final UsernamePasswordToken token = new UsernamePasswordToken("admin", "wrong_password");
+        final User admin = realm.getInternalUser("admin");
+
+        assertThrows(IncorrectCredentialsException.class, () -> realm.getAuthenticationInfo(token));
+    }
+}
diff --git a/plugins/ingest-attachment/build.gradle b/plugins/ingest-attachment/build.gradle
index 231ce40f3f38c..330a17c02bc7a 100644
--- a/plugins/ingest-attachment/build.gradle
+++ b/plugins/ingest-attachment/build.gradle
@@ -38,19 +38,26 @@ opensearchplugin {
 }
 
 versions << [
-  'tika'  : '1.24.1',
-  'pdfbox': '2.0.24',
-  'poi'   : '4.1.2',
-  'mime4j': '0.8.3'
+  'tika'  : '2.6.0',
+  'pdfbox': '2.0.27',
+  'poi'   : '5.2.3',
+  'mime4j': '0.8.8'
 ]
 
 dependencies {
   // mandatory for tika
   api "org.apache.tika:tika-core:${versions.tika}"
-  // build against Jackson 2.9.5, but still works on our current version
   api "org.apache.tika:tika-parsers:${versions.tika}"
-  api 'org.tukaani:xz:1.8'
-  api 'commons-io:commons-io:2.7'
+  // Required for the various document parsers
+  api "org.apache.tika:tika-parsers-standard-package:${versions.tika}"
+  // Required for language detection
+  api "org.apache.tika:tika-langdetect-optimaize:${versions.tika}"
+  // Optimaize libraries/dependencies
+  runtimeOnly "com.optimaize.languagedetector:language-detector:0.6"
+  runtimeOnly "com.google.guava:guava:${versions.guava}"
+  // Other dependencies
+  api 'org.tukaani:xz:1.9'
+  api 'commons-io:commons-io:2.13.0'
   api "org.slf4j:slf4j-api:${versions.slf4j}"
 
   // character set detection
@@ -62,31 +69,31 @@ dependencies {
   // Adobe PDF
   api "org.apache.pdfbox:pdfbox:${versions.pdfbox}"
   api "org.apache.pdfbox:fontbox:${versions.pdfbox}"
-  api "org.apache.pdfbox:jempbox:1.8.16"
+  api "org.apache.pdfbox:jempbox:1.8.17"
   api "commons-logging:commons-logging:${versions.commonslogging}"
-  api "org.bouncycastle:bcmail-jdk15on:${versions.bouncycastle}"
-  api "org.bouncycastle:bcprov-jdk15on:${versions.bouncycastle}"
-  api "org.bouncycastle:bcpkix-jdk15on:${versions.bouncycastle}"
+  api "org.bouncycastle:bcmail-jdk15to18:${versions.bouncycastle}"
+  api "org.bouncycastle:bcprov-jdk15to18:${versions.bouncycastle}"
+  api "org.bouncycastle:bcpkix-jdk15to18:${versions.bouncycastle}"
   // OpenOffice
   api "org.apache.poi:poi-ooxml:${versions.poi}"
   api "org.apache.poi:poi:${versions.poi}"
-  api "org.apache.poi:poi-ooxml-schemas:${versions.poi}"
+  api "org.apache.poi:poi-ooxml-lite:${versions.poi}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
-  api 'org.apache.xmlbeans:xmlbeans:3.0.1'
-  api 'org.apache.commons:commons-collections4:4.1'
+  api 'org.apache.xmlbeans:xmlbeans:5.1.1'
+  api 'org.apache.commons:commons-collections4:4.4'
   // MS Office
   api "org.apache.poi:poi-scratchpad:${versions.poi}"
   // Apple iWork
-  api 'org.apache.commons:commons-compress:1.21'
+  api "org.apache.commons:commons-compress:${versions.commonscompress}"
   // Outlook documents
   api "org.apache.james:apache-mime4j-core:${versions.mime4j}"
   api "org.apache.james:apache-mime4j-dom:${versions.mime4j}"
   // EPUB books
-  api 'org.apache.commons:commons-lang3:3.9'
+  api "org.apache.commons:commons-lang3:${versions.commonslang}"
   // Microsoft Word files with visio diagrams
   api 'org.apache.commons:commons-math3:3.6.1'
   // POIs dependency
-  api 'com.zaxxer:SparseBitSet:1.2'
+  api 'com.zaxxer:SparseBitSet:1.3'
 }
 
 restResources {
@@ -97,6 +104,8 @@ restResources {
 
 tasks.named("dependencyLicenses").configure {
   mapping from: /apache-mime4j-.*/, to: 'apache-mime4j'
+  mapping from: /tika-.*/, to: 'tika-parsers'
+  mapping from: /poi-ooxml-.*/, to: 'poi-ooxml'
 }
 
 forbiddenPatterns {
@@ -109,6 +118,22 @@ forbiddenPatterns {
 
 thirdPartyAudit {
   ignoreMissingClasses()
+  ignoreViolations(
+    // uses internal java api: sun.misc.Unsafe
+    'com.google.common.cache.Striped64',
+    'com.google.common.cache.Striped64$1',
+    'com.google.common.cache.Striped64$Cell',
+    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
+    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$1',
+    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$2',
+    'com.google.common.hash.Striped64',
+    'com.google.common.hash.Striped64$1',
+    'com.google.common.hash.Striped64$Cell',
+    'com.google.common.primitives.UnsignedBytes$LexicographicalComparatorHolder$UnsafeComparator',
+    'com.google.common.primitives.UnsignedBytes$LexicographicalComparatorHolder$UnsafeComparator$1',
+    'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper',
+    'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper$1'
+  )
 }
 
 if (BuildParams.inFipsJvm) {
diff --git a/plugins/ingest-attachment/licenses/SparseBitSet-1.2.jar.sha1 b/plugins/ingest-attachment/licenses/SparseBitSet-1.2.jar.sha1
deleted file mode 100644
index 5f1d015b87ac7..0000000000000
--- a/plugins/ingest-attachment/licenses/SparseBitSet-1.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8467c813d442837fcaeddbc42cf5c5359fab4933
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/SparseBitSet-1.3.jar.sha1 b/plugins/ingest-attachment/licenses/SparseBitSet-1.3.jar.sha1
new file mode 100644
index 0000000000000..2803db7c91e30
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/SparseBitSet-1.3.jar.sha1
@@ -0,0 +1 @@
+533eac055afe3d5f614ea95e333afd6c2bde8f26
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.3.jar.sha1 b/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.3.jar.sha1
deleted file mode 100644
index 464a34dd97643..0000000000000
--- a/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1179b56c9919c1a8e20d3a528ee4c6cee19bcbe0
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.8.jar.sha1 b/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.8.jar.sha1
new file mode 100644
index 0000000000000..77c36691d36b5
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/apache-mime4j-core-0.8.8.jar.sha1
@@ -0,0 +1 @@
+7330de23c52f71617cbec7f1d2760dae32e687cd
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.3.jar.sha1 b/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.3.jar.sha1
deleted file mode 100644
index 4f98753aa0af4..0000000000000
--- a/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e80733714eb6a70895bfc74a9528c658504c2c83
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.8.jar.sha1 b/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.8.jar.sha1
new file mode 100644
index 0000000000000..fb9c5fed27162
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/apache-mime4j-dom-0.8.8.jar.sha1
@@ -0,0 +1 @@
+e76715563a6bd150f84ccb0adb920aec8faf4779
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15on-1.70.jar.sha1 b/plugins/ingest-attachment/licenses/bcmail-jdk15on-1.70.jar.sha1
deleted file mode 100644
index 672e479eda8d7..0000000000000
--- a/plugins/ingest-attachment/licenses/bcmail-jdk15on-1.70.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-08f4aafad90f6cc7f16b9992279828ae848c9e0d
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.76.jar.sha1 b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.76.jar.sha1
new file mode 100644
index 0000000000000..46010d64015ad
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-1.76.jar.sha1
@@ -0,0 +1 @@
+23d8bcad6b57912e4633ca9955926ffcdf3c5c71
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15on-LICENSE.txt b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-LICENSE.txt
similarity index 100%
rename from plugins/ingest-attachment/licenses/bcmail-jdk15on-LICENSE.txt
rename to plugins/ingest-attachment/licenses/bcmail-jdk15to18-LICENSE.txt
diff --git a/plugins/ingest-attachment/licenses/bcmail-jdk15to18-NOTICE.txt b/plugins/ingest-attachment/licenses/bcmail-jdk15to18-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15on-1.70.jar.sha1 b/plugins/ingest-attachment/licenses/bcpkix-jdk15on-1.70.jar.sha1
deleted file mode 100644
index e348463a21257..0000000000000
--- a/plugins/ingest-attachment/licenses/bcpkix-jdk15on-1.70.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f81e5af49571a9d5a109a88f239a73ce87055417
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.76.jar.sha1 b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.76.jar.sha1
new file mode 100644
index 0000000000000..a843d972ac681
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-1.76.jar.sha1
@@ -0,0 +1 @@
+3ee440dfa1c557c1cc0c46b5dadf5ef3896ccebb
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15on-LICENSE.txt b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-LICENSE.txt
similarity index 100%
rename from plugins/ingest-attachment/licenses/bcpkix-jdk15on-LICENSE.txt
rename to plugins/ingest-attachment/licenses/bcpkix-jdk15to18-LICENSE.txt
diff --git a/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-NOTICE.txt b/plugins/ingest-attachment/licenses/bcpkix-jdk15to18-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15on-1.70.jar.sha1 b/plugins/ingest-attachment/licenses/bcprov-jdk15on-1.70.jar.sha1
deleted file mode 100644
index f5e89c0f5ed45..0000000000000
--- a/plugins/ingest-attachment/licenses/bcprov-jdk15on-1.70.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4636a0d01f74acaf28082fb62b317f1080118371
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15on-LICENSE.txt b/plugins/ingest-attachment/licenses/bcprov-jdk15on-LICENSE.txt
deleted file mode 100644
index e1fc4a1506db5..0000000000000
--- a/plugins/ingest-attachment/licenses/bcprov-jdk15on-LICENSE.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-The MIT License (MIT)
-
-Copyright (c) 2000 - 2013 The Legion of the Bouncy Castle Inc.
-                          (http://www.bouncycastle.org)
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.76.jar.sha1 b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.76.jar.sha1
new file mode 100644
index 0000000000000..2e96c404bef98
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-1.76.jar.sha1
@@ -0,0 +1 @@
+0cb53f10290a634808555bc4b34328fdab1001f2
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-LICENSE.txt b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-LICENSE.txt
new file mode 100644
index 0000000000000..9f27bafe96885
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-LICENSE.txt
@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2000 - 2013 The Legion of the Bouncy Castle Inc.
+                          (http://www.bouncycastle.org)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/plugins/ingest-attachment/licenses/bcprov-jdk15to18-NOTICE.txt b/plugins/ingest-attachment/licenses/bcprov-jdk15to18-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/ingest-attachment/licenses/commons-codec-1.13.jar.sha1 b/plugins/ingest-attachment/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-codec-1.15.jar.sha1 b/plugins/ingest-attachment/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-collections4-4.1.jar.sha1 b/plugins/ingest-attachment/licenses/commons-collections4-4.1.jar.sha1
deleted file mode 100644
index f054416580624..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-collections4-4.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a4cf4688fe1c7e3a63aa636cc96d013af537768e
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-collections4-4.4.jar.sha1 b/plugins/ingest-attachment/licenses/commons-collections4-4.4.jar.sha1
new file mode 100644
index 0000000000000..6b4ed5ab62b44
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-collections4-4.4.jar.sha1
@@ -0,0 +1 @@
+62ebe7544cb7164d87e0637a2a6a2bdc981395e8
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-compress-1.21.jar.sha1 b/plugins/ingest-attachment/licenses/commons-compress-1.21.jar.sha1
deleted file mode 100644
index 81ac609a1aa26..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-compress-1.21.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4ec95b60d4e86b5c95a0e919cb172a0af98011ef
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-compress-1.24.0.jar.sha1 b/plugins/ingest-attachment/licenses/commons-compress-1.24.0.jar.sha1
new file mode 100644
index 0000000000000..23999d1bfbde4
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-compress-1.24.0.jar.sha1
@@ -0,0 +1 @@
+b4b1b5a3d9573b2970fddab236102c0a4d27d35e
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-io-2.13.0.jar.sha1 b/plugins/ingest-attachment/licenses/commons-io-2.13.0.jar.sha1
new file mode 100644
index 0000000000000..c165136eb5822
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-io-2.13.0.jar.sha1
@@ -0,0 +1 @@
+8bb2bc9b4df17e2411533a0708a69f983bf5e83b
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-io-2.7.jar.sha1 b/plugins/ingest-attachment/licenses/commons-io-2.7.jar.sha1
deleted file mode 100644
index bbb1b15dd1e1e..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-io-2.7.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f2bd4ba11c4162733c13cc90ca7c7ea09967102
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-lang3-3.13.0.jar.sha1 b/plugins/ingest-attachment/licenses/commons-lang3-3.13.0.jar.sha1
new file mode 100644
index 0000000000000..d0c2f2486ee1f
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-lang3-3.13.0.jar.sha1
@@ -0,0 +1 @@
+b7263237aa89c1f99b327197c41d0669707a462e
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-lang3-3.9.jar.sha1 b/plugins/ingest-attachment/licenses/commons-lang3-3.9.jar.sha1
deleted file mode 100644
index 2adcfd377f87c..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-lang3-3.9.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0122c7cee69b53ed4a7681c03d4ee4c0e2765da5
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/ingest-attachment/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index 5b8f029e58293..0000000000000
--- a/plugins/ingest-attachment/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-logging-1.2.jar.sha1 b/plugins/ingest-attachment/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/commons-logging-LICENSE.txt b/plugins/ingest-attachment/licenses/commons-logging-LICENSE.txt
index d645695673349..57bc88a15a0ee 100644
--- a/plugins/ingest-attachment/licenses/commons-logging-LICENSE.txt
+++ b/plugins/ingest-attachment/licenses/commons-logging-LICENSE.txt
@@ -1,4 +1,3 @@
-
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -200,3 +199,4 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
+
diff --git a/plugins/ingest-attachment/licenses/commons-logging-NOTICE.txt b/plugins/ingest-attachment/licenses/commons-logging-NOTICE.txt
index d3d6e140ce4f3..72eb32a902458 100644
--- a/plugins/ingest-attachment/licenses/commons-logging-NOTICE.txt
+++ b/plugins/ingest-attachment/licenses/commons-logging-NOTICE.txt
@@ -1,5 +1,5 @@
-Apache Commons Logging
-Copyright 2003-2014 The Apache Software Foundation
+Apache Commons CLI
+Copyright 2001-2009 The Apache Software Foundation
 
-This product includes software developed at
+This product includes software developed by
 The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/ingest-attachment/licenses/fontbox-2.0.24.jar.sha1 b/plugins/ingest-attachment/licenses/fontbox-2.0.24.jar.sha1
deleted file mode 100644
index 1f6388867917a..0000000000000
--- a/plugins/ingest-attachment/licenses/fontbox-2.0.24.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-df8ecb3006dfcd52355a5902096e5ec34f06112e
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/fontbox-2.0.27.jar.sha1 b/plugins/ingest-attachment/licenses/fontbox-2.0.27.jar.sha1
new file mode 100644
index 0000000000000..d578dffbfa3f6
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/fontbox-2.0.27.jar.sha1
@@ -0,0 +1 @@
+d08c064d18b2b149da937d15c0d1708cba03f29d
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/guava-32.1.1-jre.jar.sha1 b/plugins/ingest-attachment/licenses/guava-32.1.1-jre.jar.sha1
new file mode 100644
index 0000000000000..0d791b5d3f55b
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/guava-32.1.1-jre.jar.sha1
@@ -0,0 +1 @@
+ad575652d84153075dd41ec6177ccb15251262b2
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/guava-LICENSE.txt b/plugins/ingest-attachment/licenses/guava-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/guava-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/ingest-attachment/licenses/guava-NOTICE.txt b/plugins/ingest-attachment/licenses/guava-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/ingest-attachment/licenses/jempbox-1.8.16.jar.sha1 b/plugins/ingest-attachment/licenses/jempbox-1.8.16.jar.sha1
deleted file mode 100644
index aba5a49037c48..0000000000000
--- a/plugins/ingest-attachment/licenses/jempbox-1.8.16.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1f41de81768ef84ca2d8cda4cb79e9272c8ee966
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/jempbox-1.8.17.jar.sha1 b/plugins/ingest-attachment/licenses/jempbox-1.8.17.jar.sha1
new file mode 100644
index 0000000000000..c0d190ad2b623
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/jempbox-1.8.17.jar.sha1
@@ -0,0 +1 @@
+388997fbd1b57f8e424c4447e3fc8ce5dd2fc665
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/language-detector-0.6.jar.sha1 b/plugins/ingest-attachment/licenses/language-detector-0.6.jar.sha1
new file mode 100644
index 0000000000000..5c069b9095db6
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/language-detector-0.6.jar.sha1
@@ -0,0 +1 @@
+52fee1eaa101f8d3e30b7095e1b6e0054d514dde
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/language-detector-LICENSE.txt b/plugins/ingest-attachment/licenses/language-detector-LICENSE.txt
new file mode 100644
index 0000000000000..a62d849a22618
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/language-detector-LICENSE.txt
@@ -0,0 +1,88 @@
+Apache License, Version 2.0
+
+Apache License
+Version 2.0, January 2004
+http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+"License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document.
+
+"Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License.
+
+"Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity.
+
+"You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License.
+
+"Source" form shall mean the preferred form for making modifications, including but not limited to software source code, documentation source, and configuration files.
+
+"Object" form shall mean any form resulting from mechanical transformation or translation of a Source form, including but not limited to compiled object code, generated documentation, and conversions to other media types.
+
+"Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below).
+
+"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.
+
+"Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner. For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Licensor or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as "Not a Contribution."
+
+"Contributor" shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work.
+
+2. Grant of Copyright License.
+
+Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.
+
+3. Grant of Patent License.
+
+Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
+
+4. Redistribution.
+
+You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:
+
+    You must give any other recipients of the Work or Derivative Works a copy of this License; and
+    You must cause any modified files to carry prominent notices stating that You changed the files; and
+    You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works; and
+    If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License.
+
+You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.
+
+5. Submission of Contributions.
+
+Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions.
+
+6. Trademarks.
+
+This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.
+
+7. Disclaimer of Warranty.
+
+Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License.
+
+8. Limitation of Liability.
+
+In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.
+
+9. Accepting Warranty or Additional Liability.
+
+While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work
+
+    To apply the Apache License to your work, attach the following boilerplate notice, with the fields enclosed by brackets "[]" replaced with your own identifying information. (Don't include the brackets!) The text should be enclosed in the appropriate comment syntax for the file format. We also recommend that a file or class name and description of purpose be included on the same "printed page" as the copyright notice for easier identification within third-party archives.
+
+       Copyright [yyyy] [name of copyright owner]
+
+       Licensed under the Apache License, Version 2.0 (the "License");
+       you may not use this file except in compliance with the License.
+       You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+       Unless required by applicable law or agreed to in writing, software
+       distributed under the License is distributed on an "AS IS" BASIS,
+       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+       See the License for the specific language governing permissions and
+       limitations under the License.
diff --git a/plugins/ingest-attachment/licenses/language-detector-NOTICE.txt b/plugins/ingest-attachment/licenses/language-detector-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/ingest-attachment/licenses/pdfbox-2.0.24.jar.sha1 b/plugins/ingest-attachment/licenses/pdfbox-2.0.24.jar.sha1
deleted file mode 100644
index 2eb2e357cbf1c..0000000000000
--- a/plugins/ingest-attachment/licenses/pdfbox-2.0.24.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-cb562ee5f43e29415af4477e62fbe668ef88d18b
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/pdfbox-2.0.27.jar.sha1 b/plugins/ingest-attachment/licenses/pdfbox-2.0.27.jar.sha1
new file mode 100644
index 0000000000000..4f670b7f95e8c
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/pdfbox-2.0.27.jar.sha1
@@ -0,0 +1 @@
+416a9dfce3714116bfdf793b15368df04266845f
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-4.1.2.jar.sha1 b/plugins/ingest-attachment/licenses/poi-4.1.2.jar.sha1
deleted file mode 100644
index dae936314bde1..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-4.1.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-964bf41cf68bce08e4ef6b2279b559fdf8d454f4
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-5.2.3.jar.sha1 b/plugins/ingest-attachment/licenses/poi-5.2.3.jar.sha1
new file mode 100644
index 0000000000000..3d8b3daf606ad
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/poi-5.2.3.jar.sha1
@@ -0,0 +1 @@
+2fb22ae74ad5aea6af1a9c64b9542f2ccf348604
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-4.1.2.jar.sha1 b/plugins/ingest-attachment/licenses/poi-ooxml-4.1.2.jar.sha1
deleted file mode 100644
index b42c94ac3b33e..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-ooxml-4.1.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-87d9a22aa9a7dd26e80c360e709f7ee02e32ab3b
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-5.2.3.jar.sha1 b/plugins/ingest-attachment/licenses/poi-ooxml-5.2.3.jar.sha1
new file mode 100644
index 0000000000000..8371593cf0841
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/poi-ooxml-5.2.3.jar.sha1
@@ -0,0 +1 @@
+02efd11c940adb18c03eb9ce7ad88fc40ee6a196
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-lite-5.2.3.jar.sha1 b/plugins/ingest-attachment/licenses/poi-ooxml-lite-5.2.3.jar.sha1
new file mode 100644
index 0000000000000..5c6365876b7be
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/poi-ooxml-lite-5.2.3.jar.sha1
@@ -0,0 +1 @@
+db113c8e9051b0ff967f4911fa20336c8325a7c5
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-4.1.2.jar.sha1 b/plugins/ingest-attachment/licenses/poi-ooxml-schemas-4.1.2.jar.sha1
deleted file mode 100644
index 852e018a5970d..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-4.1.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-550cc22a598c0b0a51d1f55f8371e83c1229802d
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-LICENSE.txt b/plugins/ingest-attachment/licenses/poi-ooxml-schemas-LICENSE.txt
deleted file mode 100644
index dd2cbd5fbc180..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-LICENSE.txt
+++ /dev/null
@@ -1,463 +0,0 @@
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
-
-APACHE POI SUBCOMPONENTS:
-
-Apache POI includes subcomponents with separate copyright notices and
-license terms. Your use of these subcomponents is subject to the terms
-and conditions of the following licenses:
-
-
-Office Open XML schemas (ooxml-schemas-1.1.jar)
-
-    The Office Open XML schema definitions used by Apache POI are
-    a part of the Office Open XML ECMA Specification (ECMA-376, [1]).
-    As defined in section 9.4 of the ECMA bylaws [2], this specification
-    is available to all interested parties without restriction:
-
-        9.4 All documents when approved shall be made available to
-            all interested parties without restriction.
-
-    Furthermore, both Microsoft and Adobe have granted patent licenses
-    to this work [3,4,5].
-
-    [1] http://www.ecma-international.org/publications/standards/Ecma-376.htm
-    [2] http://www.ecma-international.org/memento/Ecmabylaws.htm
-    [3] http://www.microsoft.com/openspecifications/en/us/programs/osp/default.aspx
-    [4] http://www.ecma-international.org/publications/files/ECMA-ST/Ecma%20PATENT/Patent%20statements%20ok/ECMA-376%20Edition%202%20Microsoft%20Patent%20Declaration.pdf
-    [5] http://www.ecma-international.org/publications/files/ECMA-ST/Ecma%20PATENT/Patent%20statements%20ok/ECMA-376%20Adobe%20Patent%20Declaration.pdf
-
-
-JUnit test library (junit-4.11.jar)
-
-    Common Public License - v 1.0
-
-    THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS COMMON
-    PUBLIC LICENSE ("AGREEMENT"). ANY USE, REPRODUCTION OR DISTRIBUTION
-    OF THE PROGRAM CONSTITUTES RECIPIENT'S ACCEPTANCE OF THIS AGREEMENT.
-
-    1. DEFINITIONS
-
-    "Contribution" means:
-
-    a) in the case of the initial Contributor, the initial code and
-       documentation distributed under this Agreement, and
-
-    b) in the case of each subsequent Contributor:
-
-       i)  changes to the Program, and
-
-       ii) additions to the Program;
-
-       where such changes and/or additions to the Program originate from
-       and are distributed by that particular Contributor. A Contribution
-       'originates' from a Contributor if it was added to the Program by
-       such Contributor itself or anyone acting on such Contributor's behalf.
-       Contributions do not include additions to the Program which: (i) are
-       separate modules of software distributed in conjunction with the
-       Program under their own license agreement, and (ii) are not derivative
-       works of the Program.
-
-    "Contributor" means any person or entity that distributes the Program.
-
-    "Licensed Patents " mean patent claims licensable by a Contributor which
-    are necessarily infringed by the use or sale of its Contribution alone
-    or when combined with the Program.
-
-    "Program" means the Contributions distributed in accordance with this
-    Agreement.
-
-    "Recipient" means anyone who receives the Program under this Agreement,
-    including all Contributors.
-
-    2. GRANT OF RIGHTS
-
-    a) Subject to the terms of this Agreement, each Contributor hereby grants
-       Recipient a non-exclusive, worldwide, royalty-free copyright license
-       to reproduce, prepare derivative works of, publicly display, publicly
-       perform, distribute and sublicense the Contribution of such
-       Contributor, if any, and such derivative works, in source code and
-       object code form.
-
-    b) Subject to the terms of this Agreement, each Contributor hereby grants
-       Recipient a non-exclusive, worldwide, royalty-free patent license under
-       Licensed Patents to make, use, sell, offer to sell, import and
-       otherwise transfer the Contribution of such Contributor, if any, in
-       source code and object code form. This patent license shall apply to
-       the combination of the Contribution and the Program if, at the time
-       the Contribution is added by the Contributor, such addition of the
-       Contribution causes such combination to be covered by the Licensed
-       Patents. The patent license shall not apply to any other combinations
-       which include the Contribution. No hardware per se is licensed
-       hereunder.
-
-    c) Recipient understands that although each Contributor grants the
-       licenses to its Contributions set forth herein, no assurances are
-       provided by any Contributor that the Program does not infringe the
-       patent or other intellectual property rights of any other entity.
-       Each Contributor disclaims any liability to Recipient for claims
-       brought by any other entity based on infringement of intellectual
-       property rights or otherwise. As a condition to exercising the rights
-       and licenses granted hereunder, each Recipient hereby assumes sole
-       responsibility to secure any other intellectual property rights
-       needed, if any. For example, if a third party patent license is
-       required to allow Recipient to distribute the Program, it is
-       Recipient's responsibility to acquire that license before
-       distributing the Program.
-
-    d) Each Contributor represents that to its knowledge it has sufficient
-       copyright rights in its Contribution, if any, to grant the copyright
-       license set forth in this Agreement.
-
-    3. REQUIREMENTS
-
-    A Contributor may choose to distribute the Program in object code form
-    under its own license agreement, provided that:
-
-    a) it complies with the terms and conditions of this Agreement; and
-
-    b) its license agreement:
-
-       i)   effectively disclaims on behalf of all Contributors all warranties
-            and conditions, express and implied, including warranties or
-            conditions of title and non-infringement, and implied warranties
-            or conditions of merchantability and fitness for a particular
-            purpose;
-
-       ii)  effectively excludes on behalf of all Contributors all liability
-            for damages, including direct, indirect, special, incidental and
-            consequential damages, such as lost profits;
-
-       iii) states that any provisions which differ from this Agreement are
-            offered by that Contributor alone and not by any other party; and
-
-       iv)  states that source code for the Program is available from such
-            Contributor, and informs licensees how to obtain it in a
-            reasonable manner on or through a medium customarily used for
-            software exchange.
-
-    When the Program is made available in source code form:
-
-    a) it must be made available under this Agreement; and
-
-    b) a copy of this Agreement must be included with each copy of
-       the Program.
-
-    Contributors may not remove or alter any copyright notices contained
-    within the Program.
-
-    Each Contributor must identify itself as the originator of its
-    Contribution, if any, in a manner that reasonably allows subsequent
-    Recipients to identify the originator of the Contribution.
-
-    4. COMMERCIAL DISTRIBUTION
-
-    Commercial distributors of software may accept certain responsibilities
-    with respect to end users, business partners and the like. While this
-    license is intended to facilitate the commercial use of the Program,
-    the Contributor who includes the Program in a commercial product offering
-    should do so in a manner which does not create potential liability for
-    other Contributors. Therefore, if a Contributor includes the Program
-    in a commercial product offering, such Contributor ("Commercial
-    Contributor") hereby agrees to defend and indemnify every other
-    Contributor ("Indemnified Contributor") against any losses, damages
-    and costs (collectively "Losses") arising from claims, lawsuits and
-    other legal actions brought by a third party against the Indemnified
-    Contributor to the extent caused by the acts or omissions of such
-    Commercial Contributor in connection with its distribution of the
-    Program in a commercial product offering. The obligations in this
-    section do not apply to any claims or Losses relating to any actual
-    or alleged intellectual property infringement. In order to qualify,
-    an Indemnified Contributor must: a) promptly notify the Commercial
-    Contributor in writing of such claim, and b) allow the Commercial
-    Contributor to control, and cooperate with the Commercial Contributor
-    in, the defense and any related settlement negotiations. The Indemnified
-    Contributor may participate in any such claim at its own expense.
-
-    For example, a Contributor might include the Program in a commercial
-    product offering, Product X. That Contributor is then a Commercial
-    Contributor. If that Commercial Contributor then makes performance
-    claims, or offers warranties related to Product X, those performance
-    claims and warranties are such Commercial Contributor's responsibility
-    alone. Under this section, the Commercial Contributor would have to
-    defend claims against the other Contributors related to those
-    performance claims and warranties, and if a court requires any other
-    Contributor to pay any damages as a result, the Commercial Contributor
-    must pay those damages.
-
-    5. NO WARRANTY
-
-    EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, THE PROGRAM IS PROVIDED
-    ON AN "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, EITHER
-    EXPRESS OR IMPLIED INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OR
-    CONDITIONS OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR
-    A PARTICULAR PURPOSE. Each Recipient is solely responsible for
-    determining the appropriateness of using and distributing the Program
-    and assumes all risks associated with its exercise of rights under this
-    Agreement, including but not limited to the risks and costs of program
-    errors, compliance with applicable laws, damage to or loss of data,
-    programs or equipment, and unavailability or interruption of operations.
-
-    6. DISCLAIMER OF LIABILITY
-
-    EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, NEITHER RECIPIENT NOR
-    ANY CONTRIBUTORS SHALL HAVE ANY LIABILITY FOR ANY DIRECT, INDIRECT,
-    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING
-    WITHOUT LIMITATION LOST PROFITS), HOWEVER CAUSED AND ON ANY THEORY OF
-    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OR
-    DISTRIBUTION OF THE PROGRAM OR THE EXERCISE OF ANY RIGHTS GRANTED
-    HEREUNDER, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
-
-    7. GENERAL
-
-    If any provision of this Agreement is invalid or unenforceable under
-    applicable law, it shall not affect the validity or enforceability of
-    the remainder of the terms of this Agreement, and without further
-    action by the parties hereto, such provision shall be reformed to the
-    minimum extent necessary to make such provision valid and enforceable.
-
-    If Recipient institutes patent litigation against a Contributor with
-    respect to a patent applicable to software (including a cross-claim or
-    counterclaim in a lawsuit), then any patent licenses granted by that
-    Contributor to such Recipient under this Agreement shall terminate as of
-    the date such litigation is filed. In addition, if Recipient institutes
-    patent litigation against any entity (including a cross-claim or
-    counterclaim in a lawsuit) alleging that the Program itself (excluding
-    combinations of the Program with other software or hardware) infringes
-    such Recipient's patent(s), then such Recipient's rights granted under
-    Section 2(b) shall terminate as of the date such litigation is filed.
-
-    All Recipient's rights under this Agreement shall terminate if it fails
-    to comply with any of the material terms or conditions of this Agreement
-    and does not cure such failure in a reasonable period of time after
-    becoming aware of such noncompliance. If all Recipient's rights under
-    this Agreement terminate, Recipient agrees to cease use and distribution
-    of the Program as soon as reasonably practicable. However, Recipient's
-    obligations under this Agreement and any licenses granted by Recipient
-    relating to the Program shall continue and survive.
-
-    Everyone is permitted to copy and distribute copies of this Agreement,
-    but in order to avoid inconsistency the Agreement is copyrighted and may
-    only be modified in the following manner. The Agreement Steward reserves
-    the right to publish new versions (including revisions) of this Agreement
-    from time to time. No one other than the Agreement Steward has the right
-    to modify this Agreement. IBM is the initial Agreement Steward. IBM may
-    assign the responsibility to serve as the Agreement Steward to a suitable
-    separate entity. Each new version of the Agreement will be given a
-    distinguishing version number. The Program (including Contributions) may
-    always be distributed subject to the version of the Agreement under which
-    it was received. In addition, after a new version of the Agreement is
-    published, Contributor may elect to distribute the Program (including
-    its Contributions) under the new version. Except as expressly stated in
-    Sections 2(a) and 2(b) above, Recipient receives no rights or licenses
-    to the intellectual property of any Contributor under this Agreement,
-    whether expressly, by implication, estoppel or otherwise. All rights in
-    the Program not expressly granted under this Agreement are reserved.
-
-    This Agreement is governed by the laws of the State of New York and the
-    intellectual property laws of the United States of America. No party to
-    this Agreement will bring a legal action under this Agreement more than
-    one year after the cause of action arose. Each party waives its rights
-    to a jury trial in any resulting litigation.
diff --git a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-NOTICE.txt b/plugins/ingest-attachment/licenses/poi-ooxml-schemas-NOTICE.txt
deleted file mode 100644
index 12ff265290de1..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-ooxml-schemas-NOTICE.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-Apache POI
-Copyright 2003-2015 The Apache Software Foundation
-
-This product includes software developed by
-The Apache Software Foundation (http://www.apache.org/).
-
-This product contains parts that were originally based on software from BEA.
-Copyright (c) 2000-2003, BEA Systems, <http://www.bea.com/>.
-
-This product contains W3C XML Schema documents. Copyright 2001-2003 (c)
-World Wide Web Consortium (Massachusetts Institute of Technology, European
-Research Consortium for Informatics and Mathematics, Keio University)
-
-This product contains the Piccolo XML Parser for Java
-(http://piccolo.sourceforge.net/). Copyright 2002 Yuval Oren.
-
-This product contains the chunks_parse_cmds.tbl file from the vsdump program.
-Copyright (C) 2006-2007 Valek Filippov (frob@df.ru)
-
-This product contains parts of the eID Applet project
-(http://eid-applet.googlecode.com). Copyright (c) 2009-2014
-FedICT (federal ICT department of Belgium), e-Contract.be BVBA (https://www.e-contract.be),
-Bart Hanssens from FedICT
diff --git a/plugins/ingest-attachment/licenses/poi-scratchpad-4.1.2.jar.sha1 b/plugins/ingest-attachment/licenses/poi-scratchpad-4.1.2.jar.sha1
deleted file mode 100644
index ed3d36c955a9e..0000000000000
--- a/plugins/ingest-attachment/licenses/poi-scratchpad-4.1.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1be379e91d3d3fb0cd11425451acdbfb0d2264e7
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/poi-scratchpad-5.2.3.jar.sha1 b/plugins/ingest-attachment/licenses/poi-scratchpad-5.2.3.jar.sha1
new file mode 100644
index 0000000000000..3c8f92498f1a4
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/poi-scratchpad-5.2.3.jar.sha1
@@ -0,0 +1 @@
+2a7fce47e22b7fedb1b277347ff4fe36d6eda50d
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/slf4j-api-1.6.2.jar.sha1 b/plugins/ingest-attachment/licenses/slf4j-api-1.6.2.jar.sha1
deleted file mode 100644
index a2f93ea55802b..0000000000000
--- a/plugins/ingest-attachment/licenses/slf4j-api-1.6.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8619e95939167fb37245b5670135e4feb0ec7d50
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/ingest-attachment/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/slf4j-api-LICENSE.txt b/plugins/ingest-attachment/licenses/slf4j-api-LICENSE.txt
index 52055e61de46f..8fda22f4d72f6 100644
--- a/plugins/ingest-attachment/licenses/slf4j-api-LICENSE.txt
+++ b/plugins/ingest-attachment/licenses/slf4j-api-LICENSE.txt
@@ -1,21 +1,21 @@
-Copyright (c) 2004-2014 QOS.ch
-All rights reserved.
-
-Permission is hereby granted, free  of charge, to any person obtaining
-a  copy  of this  software  and  associated  documentation files  (the
-"Software"), to  deal in  the Software without  restriction, including
-without limitation  the rights to  use, copy, modify,  merge, publish,
-distribute,  sublicense, and/or sell  copies of  the Software,  and to
-permit persons to whom the Software  is furnished to do so, subject to
-the following conditions:
-
-The  above  copyright  notice  and  this permission  notice  shall  be
-included in all copies or substantial portions of the Software.
-
-THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
-EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
-MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+Copyright (c) 2004-2014 QOS.ch
+All rights reserved.
+
+Permission is hereby granted, free  of charge, to any person obtaining
+a  copy  of this  software  and  associated  documentation files  (the
+"Software"), to  deal in  the Software without  restriction, including
+without limitation  the rights to  use, copy, modify,  merge, publish,
+distribute,  sublicense, and/or sell  copies of  the Software,  and to
+permit persons to whom the Software  is furnished to do so, subject to
+the following conditions:
+
+The  above  copyright  notice  and  this permission  notice  shall  be
+included in all copies or substantial portions of the Software.
+
+THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
+EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
+MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/plugins/ingest-attachment/licenses/tika-core-1.24.1.jar.sha1 b/plugins/ingest-attachment/licenses/tika-core-1.24.1.jar.sha1
deleted file mode 100644
index ba4f64ff8f078..0000000000000
--- a/plugins/ingest-attachment/licenses/tika-core-1.24.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-703e65fb300d1425d4ad7b68c21c7795bb7a95c3
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/tika-core-2.6.0.jar.sha1 b/plugins/ingest-attachment/licenses/tika-core-2.6.0.jar.sha1
new file mode 100644
index 0000000000000..c66c2f3f39401
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/tika-core-2.6.0.jar.sha1
@@ -0,0 +1 @@
+f6ed6356dd4a9bd269d873f65494376685e6192e
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/tika-core-LICENSE.txt b/plugins/ingest-attachment/licenses/tika-core-LICENSE.txt
deleted file mode 100644
index 9537d733ea9bf..0000000000000
--- a/plugins/ingest-attachment/licenses/tika-core-LICENSE.txt
+++ /dev/null
@@ -1,372 +0,0 @@
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
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-      "License" shall mean the terms and conditions for use, reproduction,
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-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
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-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
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-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
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-   6. Trademarks. This License does not grant permission to use the trade
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-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
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-   7. Disclaimer of Warranty. Unless required by applicable law or
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-      Contributor provides its Contributions) on an "AS IS" BASIS,
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-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
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-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
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-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
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-   APPENDIX: How to apply the Apache License to your work.
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-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
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-   Copyright [yyyy] [name of copyright owner]
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-   you may not use this file except in compliance with the License.
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-       http://www.apache.org/licenses/LICENSE-2.0
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-   distributed under the License is distributed on an "AS IS" BASIS,
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-   See the License for the specific language governing permissions and
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-
-
-APACHE TIKA SUBCOMPONENTS
-
-Apache Tika includes a number of subcomponents with separate copyright notices
-and license terms. Your use of these subcomponents is subject to the terms and
-conditions of the following licenses.
-
-MIME type information from file-4.26.tar.gz (http://www.darwinsys.com/file/)
-
-    Copyright (c) Ian F. Darwin 1986, 1987, 1989, 1990, 1991, 1992, 1994, 1995.
-    Software written by Ian F. Darwin and others;
-    maintained 1994- Christos Zoulas.
-
-    This software is not subject to any export provision of the United States
-    Department of Commerce, and may be exported to any country or planet.
-
-    Redistribution and use in source and binary forms, with or without
-    modification, are permitted provided that the following conditions
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-    1. Redistributions of source code must retain the above copyright
-       notice immediately at the beginning of the file, without modification,
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-    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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-    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-    SUCH DAMAGE.
-
-Charset detection code from ICU4J (http://site.icu-project.org/)
-
-    Copyright (c) 1995-2009 International Business Machines Corporation
-    and others
-
-    All rights reserved.
-
-    Permission is hereby granted, free of charge, to any person obtaining
-    a copy of this software and associated documentation files (the
-    "Software"), to deal in the Software without restriction, including
-    without limitation the rights to use, copy, modify, merge, publish,
-    distribute, and/or sell copies of the Software, and to permit persons
-    to whom the Software is furnished to do so, provided that the above
-    copyright notice(s) and this permission notice appear in all copies
-    of the Software and that both the above copyright notice(s) and this
-    permission notice appear in supporting documentation.
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-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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-    BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
-    OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
-    WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-    ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
-    SOFTWARE.
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-    Except as contained in this notice, the name of a copyright holder shall
-    not be used in advertising or otherwise to promote the sale, use or other
-    dealings in this Software without prior written authorization of the
-    copyright holder.
-
-
-Parsing functionality provided by the NetCDF Java Library (http://www.unidata.ucar.edu/software/netcdf-java/)
-
-    Copyright 1993-2010 University Corporation for Atmospheric Research/Unidata
-
-    Portions of this software were developed by the Unidata Program at the University
-    Corporation for Atmospheric Research.
-
-    Access and use of this software shall impose the following obligations and understandings
-    on the user. The user is granted the right, without any fee or cost, to use, copy, modify,
-    alter, enhance and distribute this software, and any derivative works thereof, and its
-    supporting documentation for any purpose whatsoever, provided that this entire notice
-    appears in all copies of the software, derivative works and supporting documentation. Further,
-    UCAR requests that the user credit UCAR/Unidata in any publications that result from the use
-    of this software or in any product that includes this software, although this is not an obligation.
-    The names UCAR and/or Unidata, however, may not be used in any advertising or publicity to endorse
-    or promote any products or commercial entity unless specific written permission is obtained from
-    UCAR/Unidata. The user also understands that UCAR/Unidata is not obligated to provide the user with
-    any support, consulting, training or assistance of any kind with regard to the use, operation and
-    performance of this software nor to provide the user with any updates, revisions, new versions or
-    "bug fixes."
-
-    THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
-    BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-    ARE DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
-    DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
-    OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE ACCESS,
-    USE OR PERFORMANCE OF THIS SOFTWARE.
-
-
-IPTC Photo Metadata descriptions are taken from the IPTC Photo Metadata
-Standard, July 2010, Copyright 2010 International Press Telecommunications
-Council.
-
-  1. The Specifications and Materials are licensed for use only on the condition that you agree to be bound by the terms of this license. Subject to this and other licensing requirements contained herein, you may, on a non-exclusive basis, use the Specifications and Materials.
-  2. The IPTC openly provides the Specifications and Materials for voluntary use by individuals, partnerships, companies, corporations, organizations and any other entity for use at the entity's own risk. This disclaimer, license and release is intended to apply to the IPTC, its officers, directors, agents, representatives, members, contributors, affiliates, contractors, or co-venturers acting jointly or severally.
-  3. The Document and translations thereof may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the copyright and license notices and references to the IPTC appearing in the Document and the terms of this Specifications License Agreement are included on all such copies and derivative works. Further, upon the receipt of written permission from the IPTC, the Document may be modified for the purpose of developing applications that use IPTC Specifications or as required to translate the Document into languages other than English.
-  4. Any use, duplication, distribution, or exploitation of the Document and Specifications and Materials in any manner is at your own risk.
-  5. NO WARRANTY, EXPRESSED OR IMPLIED, IS MADE REGARDING THE ACCURACY, ADEQUACY, COMPLETENESS, LEGALITY, RELIABILITY OR USEFULNESS OF ANY INFORMATION CONTAINED IN THE DOCUMENT OR IN ANY SPECIFICATION OR OTHER PRODUCT OR SERVICE PRODUCED OR SPONSORED BY THE IPTC. THE DOCUMENT AND THE INFORMATION CONTAINED HEREIN AND INCLUDED IN ANY SPECIFICATION OR OTHER PRODUCT OR SERVICE OF THE IPTC IS PROVIDED ON AN "AS IS" BASIS. THE IPTC DISCLAIMS ALL WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY ACTUAL OR ASSERTED WARRANTY OF NON-INFRINGEMENT OF PROPRIETARY RIGHTS, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. NEITHER THE IPTC NOR ITS CONTRIBUTORS SHALL BE HELD LIABLE FOR ANY IMPROPER OR INCORRECT USE OF INFORMATION. NEITHER THE IPTC NOR ITS CONTRIBUTORS ASSUME ANY RESPONSIBILITY FOR ANYONE'S USE OF INFORMATION PROVIDED BY THE IPTC. IN NO EVENT SHALL THE IPTC OR ITS CONTRIBUTORS BE LIABLE TO ANYONE FOR DAMAGES OF ANY KIND, INCLUDING BUT NOT LIMITED TO, COMPENSATORY DAMAGES, LOST PROFITS, LOST DATA OR ANY FORM OF SPECIAL, INCIDENTAL, INDIRECT, CONSEQUENTIAL OR PUNITIVE DAMAGES OF ANY KIND WHETHER BASED ON BREACH OF CONTRACT OR WARRANTY, TORT, PRODUCT LIABILITY OR OTHERWISE.
-  6. The IPTC takes no position regarding the validity or scope of any Intellectual Property or other rights that might be claimed to pertain to the implementation or use of the technology described in the Document or the extent to which any license under such rights might or might not be available. The IPTC does not represent that it has made any effort to identify any such rights. Copies of claims of rights made available for publication, assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of the Specifications and Materials, can be obtained from the Managing Director of the IPTC.
-  7. By using the Specifications and Materials including the Document in any manner or for any purpose, you release the IPTC from all liabilities, claims, causes of action, allegations, losses, injuries, damages, or detriments of any nature arising from or relating to the use of the Specifications, Materials or any portion thereof. You further agree not to file a lawsuit, make a claim, or take any other formal or informal legal action against the IPTC, resulting from your acquisition, use, duplication, distribution, or exploitation of the Specifications, Materials or any portion thereof. Finally, you hereby agree that the IPTC is not liable for any direct, indirect, special or consequential damages arising from or relating to your acquisition, use, duplication, distribution, or exploitation of the Specifications, Materials or any portion thereof.
-  8. Specifications and Materials may be downloaded or copied provided that ALL copies retain the ownership, copyright and license notices.
-  9. Materials may not be edited, modified, or presented in a context that creates a misleading or false impression or statement as to the positions, actions, or statements of the IPTC.
-  10. The name and trademarks of the IPTC may not be used in advertising, publicity, or in relation to products or services and their names without the specific, written prior permission of the IPTC. Any permitted use of the trademarks of the IPTC, whether registered or not, shall be accompanied by an appropriate mark and attribution, as agreed with the IPTC.
-  11. Specifications may be extended by both members and non-members to provide additional functionality (Extension Specifications) provided that there is a clear recognition of the IPTC IP and its ownership in the Extension Specifications and the related documentation and provided that the extensions are clearly identified and provided that a perpetual license is granted by the creator of the Extension Specifications for other members and non-members to use the Extension Specifications and to continue extensions of the Extension Specifications. The IPTC does not waive any of its rights in the Specifications and Materials in this context. The Extension Specifications may be considered the intellectual property of their creator. The IPTC expressly disclaims any responsibility for damage caused by an extension to the Specifications.
-  12. Specifications and Materials may be included in derivative work of both members and non-members provided that there is a clear recognition of the IPTC IP and its ownership in the derivative work and its related documentation. The IPTC does not waive any of its rights in the Specifications and Materials in this context. Derivative work in its entirety may be considered the intellectual property of the creator of the work .The IPTC expressly disclaims any responsibility for damage caused when its IP is used in a derivative context.
-  13. This Specifications License Agreement is perpetual subject to your conformance to the terms of this Agreement. The IPTC may terminate this Specifications License Agreement immediately upon your breach of this Agreement and, upon such termination you will cease all use, duplication, distribution, and/or exploitation in any manner of the Specifications and Materials.
-  14. This Specifications License Agreement reflects the entire agreement of the parties regarding the subject matter hereof and supersedes all prior agreements or representations regarding such matters, whether written or oral. To the extent any portion or provision of this Specifications License Agreement is found to be illegal or unenforceable, then the remaining provisions of this Specifications License Agreement will remain in full force and effect and the illegal or unenforceable provision will be construed to give it such effect as it may properly have that is consistent with the intentions of the parties.
-  15. This Specifications License Agreement may only be modified in writing signed by an authorized representative of the IPTC.
-  16. This Specifications License Agreement is governed by the law of United Kingdom, as such law is applied to contracts made and fully performed in the United Kingdom. Any disputes arising from or relating to this Specifications License Agreement will be resolved in the courts of the United Kingdom. You consent to the jurisdiction of such courts over you and covenant not to assert before such courts any objection to proceeding in such forums.
-
-
-JUnRAR (https://github.com/edmund-wagner/junrar/)
-
-      JUnRAR is based on the UnRAR tool, and covered by the same license
-      It was formerly available from http://java-unrar.svn.sourceforge.net/
-
- ******    *****   ******   UnRAR - free utility for RAR archives
- **   **  **   **  **   **  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- ******   *******  ******    License for use and distribution of
- **   **  **   **  **   **   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- **   **  **   **  **   **         FREE portable version
-                                   ~~~~~~~~~~~~~~~~~~~~~
-
-      The source code of UnRAR utility is freeware. This means:
-
-   1. All copyrights to RAR and the utility UnRAR are exclusively
-      owned by the author - Alexander Roshal.
-
-   2. The UnRAR sources may be used in any software to handle RAR
-      archives without limitations free of charge, but cannot be used
-      to re-create the RAR compression algorithm, which is proprietary.
-      Distribution of modified UnRAR sources in separate form or as a
-      part of other software is permitted, provided that it is clearly
-      stated in the documentation and source comments that the code may
-      not be used to develop a RAR (WinRAR) compatible archiver.
-
-   3. The UnRAR utility may be freely distributed. It is allowed
-      to distribute UnRAR inside of other software packages.
-
-   4. THE RAR ARCHIVER AND THE UnRAR UTILITY ARE DISTRIBUTED "AS IS".
-      NO WARRANTY OF ANY KIND IS EXPRESSED OR IMPLIED.  YOU USE AT
-      YOUR OWN RISK. THE AUTHOR WILL NOT BE LIABLE FOR DATA LOSS,
-      DAMAGES, LOSS OF PROFITS OR ANY OTHER KIND OF LOSS WHILE USING
-      OR MISUSING THIS SOFTWARE.
-
-   5. Installing and using the UnRAR utility signifies acceptance of
-      these terms and conditions of the license.
-
-   6. If you don't agree with terms of the license you must remove
-      UnRAR files from your storage devices and cease to use the
-      utility.
-
-      Thank you for your interest in RAR and UnRAR.  Alexander L. Roshal
-
-Sqlite (bundled in org.xerial's sqlite-jdbc)
-    This product bundles Sqlite, which is in the Public Domain.  For details
-    see: https://www.sqlite.org/copyright.html
diff --git a/plugins/ingest-attachment/licenses/tika-core-NOTICE.txt b/plugins/ingest-attachment/licenses/tika-core-NOTICE.txt
deleted file mode 100644
index 8e94f644b8112..0000000000000
--- a/plugins/ingest-attachment/licenses/tika-core-NOTICE.txt
+++ /dev/null
@@ -1,17 +0,0 @@
-Apache Tika
-Copyright 2015 The Apache Software Foundation
-
-This product includes software developed at
-The Apache Software Foundation (http://www.apache.org/).
-
-Copyright 1993-2010 University Corporation for Atmospheric Research/Unidata
-This software contains code derived from UCAR/Unidata's NetCDF library.
-
-Tika-server component uses CDDL-licensed dependencies: jersey (http://jersey.java.net/) and
-Grizzly (http://grizzly.java.net/)
-
-Tika-parsers component uses CDDL/LGPL dual-licensed dependency: jhighlight (https://github.com/codelibs/jhighlight)
-
-OpenCSV: Copyright 2005 Bytecode Pty Ltd. Licensed under the Apache License, Version 2.0
-
-IPTC Photo Metadata descriptions Copyright 2010 International Press Telecommunications Council.
diff --git a/plugins/ingest-attachment/licenses/tika-langdetect-optimaize-2.6.0.jar.sha1 b/plugins/ingest-attachment/licenses/tika-langdetect-optimaize-2.6.0.jar.sha1
new file mode 100644
index 0000000000000..e7bc59bb5ae49
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/tika-langdetect-optimaize-2.6.0.jar.sha1
@@ -0,0 +1 @@
+72b784a7bdab0ffde005fa64d15e3f077331d6fc
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/tika-parsers-1.24.1.jar.sha1 b/plugins/ingest-attachment/licenses/tika-parsers-1.24.1.jar.sha1
deleted file mode 100644
index 6ad33ac8eca37..0000000000000
--- a/plugins/ingest-attachment/licenses/tika-parsers-1.24.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-02ce8d709cef4ed6a1a51ff14ba15b2ba2e76f09
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/tika-parsers-standard-package-2.6.0.jar.sha1 b/plugins/ingest-attachment/licenses/tika-parsers-standard-package-2.6.0.jar.sha1
new file mode 100644
index 0000000000000..83c0777fcbe8a
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/tika-parsers-standard-package-2.6.0.jar.sha1
@@ -0,0 +1 @@
+00980e70b1df13c1236b750f0ca1462edd5d7417
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/xmlbeans-3.0.1.jar.sha1 b/plugins/ingest-attachment/licenses/xmlbeans-3.0.1.jar.sha1
deleted file mode 100644
index e1c74c67f214d..0000000000000
--- a/plugins/ingest-attachment/licenses/xmlbeans-3.0.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-50d94da791ab1e799a11d6f82410fd7d49f402ca
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/xmlbeans-5.1.1.jar.sha1 b/plugins/ingest-attachment/licenses/xmlbeans-5.1.1.jar.sha1
new file mode 100644
index 0000000000000..4d1d2ad0807e7
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/xmlbeans-5.1.1.jar.sha1
@@ -0,0 +1 @@
+48a369df0eccb509d46203104e4df9cb00f0f68b
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/xz-1.8.jar.sha1 b/plugins/ingest-attachment/licenses/xz-1.8.jar.sha1
deleted file mode 100644
index 7455feac7983b..0000000000000
--- a/plugins/ingest-attachment/licenses/xz-1.8.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c4f7d054303948eb6a4066194253886c8af07128
\ No newline at end of file
diff --git a/plugins/ingest-attachment/licenses/xz-1.9.jar.sha1 b/plugins/ingest-attachment/licenses/xz-1.9.jar.sha1
new file mode 100644
index 0000000000000..c3e22d167212f
--- /dev/null
+++ b/plugins/ingest-attachment/licenses/xz-1.9.jar.sha1
@@ -0,0 +1 @@
+1ea4bec1a921180164852c65006d928617bd2caf
\ No newline at end of file
diff --git a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/AttachmentProcessor.java b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/AttachmentProcessor.java
index 0eb864a2d9ac0..54d2e0c7832e6 100644
--- a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/AttachmentProcessor.java
+++ b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/AttachmentProcessor.java
@@ -33,12 +33,12 @@
 package org.opensearch.ingest.attachment;
 
 import org.apache.tika.exception.ZeroByteFileException;
-import org.apache.tika.language.LanguageIdentifier;
+import org.apache.tika.langdetect.optimaize.OptimaizeLangDetector;
+import org.apache.tika.language.detect.LanguageResult;
 import org.apache.tika.metadata.Metadata;
 import org.apache.tika.metadata.TikaCoreProperties;
-
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Processor;
@@ -134,9 +134,10 @@ public IngestDocument execute(IngestDocument ingestDocument) {
         }
 
         if (properties.contains(Property.LANGUAGE) && Strings.hasLength(parsedContent)) {
-            // TODO: stop using LanguageIdentifier...
-            LanguageIdentifier identifier = new LanguageIdentifier(parsedContent);
-            String language = identifier.getLanguage();
+            OptimaizeLangDetector langDetector = new OptimaizeLangDetector();
+            langDetector.loadModels();
+            LanguageResult result = langDetector.detect(parsedContent);
+            String language = result.getLanguage();
             additionalFields.put(Property.LANGUAGE.toLowerCase(), language);
         }
 
@@ -158,6 +159,12 @@ public IngestDocument execute(IngestDocument ingestDocument) {
             String author = metadata.get("Author");
             if (Strings.hasLength(author)) {
                 additionalFields.put(Property.AUTHOR.toLowerCase(), author);
+            } else {
+                // The MSOffice parser has deprecated "Author" in favor of "Creator"
+                author = metadata.get(TikaCoreProperties.CREATOR);
+                if (Strings.hasLength(author)) {
+                    additionalFields.put(Property.AUTHOR.toLowerCase(), author);
+                }
             }
         }
 
@@ -165,6 +172,12 @@ public IngestDocument execute(IngestDocument ingestDocument) {
             String keywords = metadata.get("Keywords");
             if (Strings.hasLength(keywords)) {
                 additionalFields.put(Property.KEYWORDS.toLowerCase(), keywords);
+            } else {
+                // Fallback - EPUBs put their keywords as multiple subject fields by convention
+                keywords = metadata.get(TikaCoreProperties.SUBJECT);
+                if (Strings.hasLength(keywords)) {
+                    additionalFields.put(Property.KEYWORDS.toLowerCase(), keywords);
+                }
             }
         }
 
diff --git a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/IngestAttachmentPlugin.java b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/IngestAttachmentPlugin.java
index a7e51b21c3c1a..a1d1b07e73f5d 100644
--- a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/IngestAttachmentPlugin.java
+++ b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/IngestAttachmentPlugin.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.ingest.attachment;
 
-import java.util.Collections;
-import java.util.Map;
-
 import org.opensearch.ingest.Processor;
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.plugins.Plugin;
 
+import java.util.Collections;
+import java.util.Map;
+
 public class IngestAttachmentPlugin extends Plugin implements IngestPlugin {
 
     @Override
diff --git a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/TikaImpl.java b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/TikaImpl.java
index 2451eee8e984b..ce7ceb5e3d776 100644
--- a/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/TikaImpl.java
+++ b/plugins/ingest-attachment/src/main/java/org/opensearch/ingest/attachment/TikaImpl.java
@@ -42,7 +42,6 @@
 import org.opensearch.SpecialPermission;
 import org.opensearch.bootstrap.FilePermissionUtils;
 import org.opensearch.bootstrap.JarHell;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
 
@@ -93,9 +92,9 @@ final class TikaImpl {
     private static final Parser PARSERS[] = new Parser[] {
         // documents
         new org.apache.tika.parser.html.HtmlParser(),
-        new org.apache.tika.parser.rtf.RTFParser(),
         new org.apache.tika.parser.pdf.PDFParser(),
         new org.apache.tika.parser.txt.TXTParser(),
+        new org.apache.tika.parser.microsoft.rtf.RTFParser(),
         new org.apache.tika.parser.microsoft.OfficeParser(),
         new org.apache.tika.parser.microsoft.OldExcelParser(),
         ParserDecorator.withoutTypes(new org.apache.tika.parser.microsoft.ooxml.OOXMLParser(), EXCLUDES),
@@ -181,14 +180,6 @@ static PermissionCollection getRestrictedPermissions() {
         perms.add(new RuntimePermission("accessClassInPackage.sun.java2d.cmm.kcms"));
         // xmlbeans, use by POI, needs to get the context classloader
         perms.add(new RuntimePermission("getClassLoader"));
-        // ZipFile needs accessDeclaredMembers on JDK 10; cf. https://bugs.openjdk.java.net/browse/JDK-8187485
-        if (JavaVersion.current().compareTo(JavaVersion.parse("10")) >= 0) {
-            if (JavaVersion.current().compareTo(JavaVersion.parse("11")) < 0) {
-                // TODO remove this and from plugin-security.policy when JDK 11 is the only one we support
-                // this is needed pre 11, but it's fixed in 11 : https://bugs.openjdk.java.net/browse/JDK-8187485
-                perms.add(new RuntimePermission("accessDeclaredMembers"));
-            }
-        }
         perms.setReadOnly();
         return perms;
     }
diff --git a/plugins/ingest-attachment/src/main/plugin-metadata/plugin-security.policy b/plugins/ingest-attachment/src/main/plugin-metadata/plugin-security.policy
index 0fa85f6f040f6..4b90f9a21aae4 100644
--- a/plugins/ingest-attachment/src/main/plugin-metadata/plugin-security.policy
+++ b/plugins/ingest-attachment/src/main/plugin-metadata/plugin-security.policy
@@ -35,9 +35,6 @@ grant {
   // needed to apply additional sandboxing to tika parsing
   permission java.security.SecurityPermission "createAccessControlContext";
 
-  // TODO: fix PDFBox not to actually install bouncy castle like this
-  permission java.security.SecurityPermission "putProviderProperty.BC";
-  permission java.security.SecurityPermission "insertProvider";
   // TODO: fix POI XWPF to not do this: https://bz.apache.org/bugzilla/show_bug.cgi?id=58597
   permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
   // needed by xmlbeans, as part of POI for MS xml docs
diff --git a/plugins/ingest-attachment/src/test/java/org/opensearch/ingest/attachment/AttachmentProcessorTests.java b/plugins/ingest-attachment/src/test/java/org/opensearch/ingest/attachment/AttachmentProcessorTests.java
index e9c87ae3a6109..17d73a74b6073 100644
--- a/plugins/ingest-attachment/src/test/java/org/opensearch/ingest/attachment/AttachmentProcessorTests.java
+++ b/plugins/ingest-attachment/src/test/java/org/opensearch/ingest/attachment/AttachmentProcessorTests.java
@@ -33,13 +33,11 @@
 package org.opensearch.ingest.attachment;
 
 import org.apache.commons.io.IOUtils;
-
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Processor;
 import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.test.OpenSearchTestCase;
-
 import org.junit.Before;
 
 import java.io.InputStream;
@@ -138,8 +136,8 @@ public void testUnknownLanguageDocument() throws Exception {
         Map<String, Object> attachmentData = parseDocument("text-gibberish.txt", processor);
 
         assertThat(attachmentData.keySet(), hasItem("language"));
-        // lt seems some standard for not detected
-        assertThat(attachmentData.get("language"), is("lt"));
+        // Note - this output is non-deterministic across library versions
+        assertThat(attachmentData.get("language"), is("sl"));
     }
 
     public void testEmptyTextDocument() throws Exception {
@@ -378,8 +376,9 @@ public void testIndexedChars() throws Exception {
 
         attachmentData = parseDocument("text-in-english.txt", processor, Collections.singletonMap("max_length", 10));
 
+        // Language detection is not accurate when the text to analyze is short
         assertThat(attachmentData.keySet(), containsInAnyOrder("language", "content", "content_type", "content_length"));
-        assertThat(attachmentData.get("language"), is("sk"));
+        assertThat(attachmentData.get("language"), not(is("en")));
         assertThat(attachmentData.get("content"), is("\"God Save"));
         assertThat(attachmentData.get("content_type").toString(), containsString("text/plain"));
         assertThat(attachmentData.get("content_length"), is(10L));
diff --git a/plugins/ingest-attachment/src/test/resources/org/opensearch/ingest/attachment/test/sample-files/asciidoc.asciidoc b/plugins/ingest-attachment/src/test/resources/org/opensearch/ingest/attachment/test/sample-files/asciidoc.asciidoc
index dc06d4e83dd30..4a2b2c388cfc1 100644
--- a/plugins/ingest-attachment/src/test/resources/org/opensearch/ingest/attachment/test/sample-files/asciidoc.asciidoc
+++ b/plugins/ingest-attachment/src/test/resources/org/opensearch/ingest/attachment/test/sample-files/asciidoc.asciidoc
@@ -2,4 +2,3 @@
 = AsciiDoc test
 
 Here is a test of the asciidoc format.
-
diff --git a/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/10_basic.yml b/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/10_basic.yml
index 607fa5bf8b781..09075e0573fbe 100644
--- a/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/10_basic.yml
+++ b/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/10_basic.yml
@@ -5,11 +5,10 @@
     - do:
         cluster.state: {}
 
-    - set: {master_node: master}
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { 'nodes.$master.plugins': { name: ingest-attachment }  }
-    - contains:  { 'nodes.$master.ingest.processors': { type: attachment } }
-
+    - contains:  { 'nodes.$cluster_manager.plugins': { name: ingest-attachment }  }
+    - contains:  { 'nodes.$cluster_manager.ingest.processors': { type: attachment } }
diff --git a/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/30_files_supported.yml b/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/30_files_supported.yml
index 7407c2a9326f6..58833b037b8cc 100644
--- a/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/30_files_supported.yml
+++ b/plugins/ingest-attachment/src/yamlRestTest/resources/rest-api-spec/test/ingest_attachment/30_files_supported.yml
@@ -29,7 +29,7 @@
         id: 1
   - length: { _source.attachment: 6 }
   - match: { _source.attachment.content: "Test opensearch" }
-  - match: { _source.attachment.language: "pl" }
+  - match: { _source.attachment.language: "en" }
   - match: { _source.attachment.author: "OpenSearch" }
   - match: { _source.attachment.date: "2021-03-27T04:12:00Z" }
   - match: { _source.attachment.content_length: 16 }
@@ -67,7 +67,7 @@
         id: 1
   - length: { _source.attachment: 6 }
   - match: { _source.attachment.content: "Test opensearch" }
-  - match: { _source.attachment.language: "pl" }
+  - match: { _source.attachment.language: "en" }
   - match: { _source.attachment.author: "OpenSearch" }
   - match: { _source.attachment.date: "2021-03-27T04:12:00Z" }
   - match: { _source.attachment.content_length: 16 }
diff --git a/plugins/mapper-annotated-text/src/internalClusterTest/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapperTests.java b/plugins/mapper-annotated-text/src/internalClusterTest/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapperTests.java
index 87933ab3df6be..9bfd5669e731b 100644
--- a/plugins/mapper-annotated-text/src/internalClusterTest/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapperTests.java
+++ b/plugins/mapper-annotated-text/src/internalClusterTest/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapperTests.java
@@ -47,10 +47,9 @@
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.CharFilterFactory;
@@ -99,7 +98,7 @@ protected void writeFieldValue(XContentBuilder builder) throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     @Override
@@ -396,92 +395,87 @@ public void testPositionIncrementGap() throws IOException {
     }
 
     public void testSearchAnalyzerSerialization() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "standard")
-                .field("search_analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "standard")
+            .field("search_analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // special case: default index analyzer
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "default")
-                .field("search_analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "default")
+            .field("search_analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // special case: default search analyzer
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "keyword")
-                .field("search_analyzer", "default")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "keyword")
+            .field("search_analyzer", "default")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapper = createDocumentMapper("_doc", mapping);
 
         XContentBuilder builder = XContentFactory.jsonBuilder();
@@ -489,48 +483,46 @@ public void testSearchAnalyzerSerialization() throws IOException {
         mapper.toXContent(builder, new ToXContent.MapParams(Collections.singletonMap("include_defaults", "true")));
         builder.endObject();
 
-        String mappingString = Strings.toString(builder);
+        String mappingString = builder.toString();
         assertTrue(mappingString.contains("analyzer"));
         assertTrue(mappingString.contains("search_analyzer"));
         assertTrue(mappingString.contains("search_quote_analyzer"));
     }
 
     public void testSearchQuoteAnalyzerSerialization() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "standard")
-                .field("search_analyzer", "standard")
-                .field("search_quote_analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "standard")
+            .field("search_analyzer", "standard")
+            .field("search_quote_analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // special case: default index/search analyzer
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "annotated_text")
-                .field("analyzer", "default")
-                .field("search_analyzer", "default")
-                .field("search_quote_analyzer", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "annotated_text")
+            .field("analyzer", "default")
+            .field("search_analyzer", "default")
+            .field("search_quote_analyzer", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
diff --git a/plugins/mapper-annotated-text/src/main/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapper.java b/plugins/mapper-annotated-text/src/main/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapper.java
index e377a7c030f37..935887261dcc9 100644
--- a/plugins/mapper-annotated-text/src/main/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapper.java
+++ b/plugins/mapper-annotated-text/src/main/java/org/opensearch/index/mapper/annotatedtext/AnnotatedTextFieldMapper.java
@@ -44,7 +44,6 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.index.IndexOptions;
-
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
diff --git a/plugins/mapper-annotated-text/src/test/java/org/opensearch/search/fetch/subphase/highlight/AnnotatedTextHighlighterTests.java b/plugins/mapper-annotated-text/src/test/java/org/opensearch/search/fetch/subphase/highlight/AnnotatedTextHighlighterTests.java
index d2d009f1b28b8..34851cf9bcbae 100644
--- a/plugins/mapper-annotated-text/src/test/java/org/opensearch/search/fetch/subphase/highlight/AnnotatedTextHighlighterTests.java
+++ b/plugins/mapper-annotated-text/src/test/java/org/opensearch/search/fetch/subphase/highlight/AnnotatedTextHighlighterTests.java
@@ -41,7 +41,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -56,7 +55,8 @@
 import org.apache.lucene.search.uhighlight.Snippet;
 import org.apache.lucene.search.uhighlight.SplittingBreakIterator;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.Strings;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.mapper.annotatedtext.AnnotatedTextFieldMapper.AnnotatedHighlighterAnalyzer;
 import org.opensearch.index.mapper.annotatedtext.AnnotatedTextFieldMapper.AnnotatedText;
 import org.opensearch.index.mapper.annotatedtext.AnnotatedTextFieldMapper.AnnotationAnalyzerWrapper;
@@ -67,8 +67,8 @@
 import java.util.ArrayList;
 import java.util.Locale;
 
-import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 import static org.hamcrest.CoreMatchers.equalTo;
+import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 
 public class AnnotatedTextHighlighterTests extends OpenSearchTestCase {
 
@@ -136,7 +136,8 @@ private void assertHighlightOneDoc(
             noMatchSize,
             expectedPassages.length,
             name -> "text".equals(name),
-            Integer.MAX_VALUE
+            Integer.MAX_VALUE,
+            null
         );
         highlighter.setFieldMatcher((name) -> "text".equals(name));
         final Snippet[] snippets = highlighter.highlightField(getOnlyLeafReader(reader), topDocs.scoreDocs[0].doc, () -> rawValue);
diff --git a/plugins/mapper-annotated-text/src/yamlRestTest/resources/rest-api-spec/test/mapper_annotatedtext/10_basic.yml b/plugins/mapper-annotated-text/src/yamlRestTest/resources/rest-api-spec/test/mapper_annotatedtext/10_basic.yml
index b4acccf36879d..0e43e9e40b619 100644
--- a/plugins/mapper-annotated-text/src/yamlRestTest/resources/rest-api-spec/test/mapper_annotatedtext/10_basic.yml
+++ b/plugins/mapper-annotated-text/src/yamlRestTest/resources/rest-api-spec/test/mapper_annotatedtext/10_basic.yml
@@ -142,4 +142,3 @@
         request_cache: false
         body: { "query" : {"match_phrase" : { "my_field" : {"query": "~MARK0", "analyzer": "whitespace"} } }, "highlight" : { "type" : "annotated",  "fields" : { "my_field" : {} } } }
   - match: {_shards.failed: 0}
-
diff --git a/plugins/mapper-murmur3/src/test/java/org/opensearch/index/mapper/murmur3/Murmur3FieldMapperTests.java b/plugins/mapper-murmur3/src/test/java/org/opensearch/index/mapper/murmur3/Murmur3FieldMapperTests.java
index 5cfbc0cde1050..04d46db50592c 100644
--- a/plugins/mapper-murmur3/src/test/java/org/opensearch/index/mapper/murmur3/Murmur3FieldMapperTests.java
+++ b/plugins/mapper-murmur3/src/test/java/org/opensearch/index/mapper/murmur3/Murmur3FieldMapperTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperTestCase;
 import org.opensearch.index.mapper.ParsedDocument;
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
 
 public class Murmur3FieldMapperTests extends MapperTestCase {
 
@@ -55,7 +56,7 @@ protected void writeFieldValue(XContentBuilder builder) throws IOException {
 
     @Override
     protected Collection<? extends Plugin> getPlugins() {
-        return org.opensearch.common.collect.List.of(new MapperMurmur3Plugin());
+        return List.of(new MapperMurmur3Plugin());
     }
 
     @Override
diff --git a/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingIT.java b/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingIT.java
index 3a430331167f6..51e0979324623 100644
--- a/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingIT.java
+++ b/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingIT.java
@@ -34,8 +34,8 @@
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugin.mapper.MapperSizePlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -123,7 +123,7 @@ private void assertSizeMappingEnabled(String index, boolean enabled) throws IOEx
     public void testBasic() throws Exception {
         assertAcked(prepareCreate("test").setMapping("_size", "enabled=true"));
         final String source = "{\"f\":10}";
-        indexRandom(true, client().prepareIndex("test").setId("1").setSource(source, XContentType.JSON));
+        indexRandom(true, client().prepareIndex("test").setId("1").setSource(source, MediaTypeRegistry.JSON));
         GetResponse getResponse = client().prepareGet("test", "1").setStoredFields("_size").get();
         assertNotNull(getResponse.getField("_size"));
         assertEquals(source.length(), (int) getResponse.getField("_size").getValue());
diff --git a/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingTests.java b/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingTests.java
index 4e4648a87fbfc..e7e8d92cee65a 100644
--- a/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingTests.java
+++ b/plugins/mapper-size/src/internalClusterTest/java/org/opensearch/index/mapper/size/SizeMappingTests.java
@@ -32,29 +32,27 @@
 
 package org.opensearch.index.mapper.size;
 
-import java.util.Collection;
-
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
+import org.apache.lucene.index.IndexableField;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
-import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.DocumentMapper;
+import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.plugin.mapper.MapperSizePlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
+import java.util.Collection;
 
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
 
-import org.apache.lucene.index.IndexableField;
-
 public class SizeMappingTests extends OpenSearchSingleNodeTestCase {
     @Override
     protected Collection<Class<? extends Plugin>> getPlugins() {
@@ -66,7 +64,7 @@ public void testSizeEnabled() throws Exception {
         DocumentMapper docMapper = service.mapperService().documentMapper();
 
         BytesReference source = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject());
-        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, XContentType.JSON));
+        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, MediaTypeRegistry.JSON));
 
         boolean stored = false;
         boolean points = false;
@@ -83,7 +81,7 @@ public void testSizeDisabled() throws Exception {
         DocumentMapper docMapper = service.mapperService().documentMapper();
 
         BytesReference source = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject());
-        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, XContentType.JSON));
+        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, MediaTypeRegistry.JSON));
 
         assertThat(doc.rootDoc().getField("_size"), nullValue());
     }
@@ -93,7 +91,7 @@ public void testSizeNotSet() throws Exception {
         DocumentMapper docMapper = service.mapperService().documentMapper();
 
         BytesReference source = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject());
-        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, XContentType.JSON));
+        ParsedDocument doc = docMapper.parse(new SourceToParse("test", "1", source, MediaTypeRegistry.JSON));
 
         assertThat(doc.rootDoc().getField("_size"), nullValue());
     }
@@ -103,16 +101,15 @@ public void testThatDisablingWorksWhenMerging() throws Exception {
         DocumentMapper docMapper = service.mapperService().documentMapper();
         assertThat(docMapper.metadataMapper(SizeFieldMapper.class).enabled(), is(true));
 
-        String disabledMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_size")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String disabledMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_size")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         docMapper = service.mapperService()
             .merge("type", new CompressedXContent(disabledMapping), MapperService.MergeReason.MAPPING_UPDATE);
 
diff --git a/plugins/repository-azure/build.gradle b/plugins/repository-azure/build.gradle
index 60fb99f459454..2695d3f99576d 100644
--- a/plugins/repository-azure/build.gradle
+++ b/plugins/repository-azure/build.gradle
@@ -44,9 +44,10 @@ opensearchplugin {
 }
 
 dependencies {
-  api 'com.azure:azure-core:1.26.0'
-  api 'com.azure:azure-storage-common:12.15.0'
-  api 'com.azure:azure-core-http-netty:1.11.8'
+  api 'com.azure:azure-core:1.39.0'
+  api 'com.azure:azure-json:1.0.1'
+  api 'com.azure:azure-storage-common:12.21.1'
+  api 'com.azure:azure-core-http-netty:1.12.8'
   api "io.netty:netty-codec-dns:${versions.netty}"
   api "io.netty:netty-codec-socks:${versions.netty}"
   api "io.netty:netty-codec-http2:${versions.netty}"
@@ -54,22 +55,22 @@ dependencies {
   api "io.netty:netty-resolver-dns:${versions.netty}"
   api "io.netty:netty-transport-native-unix-common:${versions.netty}"
   implementation project(':modules:transport-netty4')
-  api 'com.azure:azure-storage-blob:12.14.4'
+  api 'com.azure:azure-storage-blob:12.23.0'
   api 'org.reactivestreams:reactive-streams:1.0.3'
-  api 'io.projectreactor:reactor-core:3.4.15'
-  api 'io.projectreactor.netty:reactor-netty:1.0.16'
-  api 'io.projectreactor.netty:reactor-netty-core:1.0.16'
-  api 'io.projectreactor.netty:reactor-netty-http:1.0.16'
+  api 'io.projectreactor:reactor-core:3.5.6'
+  api 'io.projectreactor.netty:reactor-netty:1.1.8'
+  api 'io.projectreactor.netty:reactor-netty-core:1.1.8'
+  api 'io.projectreactor.netty:reactor-netty-http:1.1.9'
   api "org.slf4j:slf4j-api:${versions.slf4j}"
   api "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
-  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
   api "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:${versions.jackson}"
   api "com.fasterxml.jackson.dataformat:jackson-dataformat-xml:${versions.jackson}"
   api "com.fasterxml.jackson.module:jackson-module-jaxb-annotations:${versions.jackson}"
   api 'org.codehaus.woodstox:stax2-api:4.2.1'
-  implementation 'com.fasterxml.woodstox:woodstox-core:6.2.8'
-  runtimeOnly 'com.google.guava:guava:31.1-jre'
-  api 'org.apache.commons:commons-lang3:3.12.0'
+  implementation "com.fasterxml.woodstox:woodstox-core:${versions.woodstox}"
+  runtimeOnly "com.google.guava:guava:${versions.guava}"
+  api "org.apache.commons:commons-lang3:${versions.commonslang}"
   testImplementation project(':test:fixtures:azure-fixture')
 }
 
@@ -137,7 +138,7 @@ thirdPartyAudit {
     'javax.xml.bind.annotation.XmlAccessOrder',
     'javax.xml.bind.annotation.XmlAccessType',
     'javax.xml.bind.annotation.XmlAccessorOrder',
-    'javax.xml.bind.annotation.XmlAccessorType', 
+    'javax.xml.bind.annotation.XmlAccessorType',
     'javax.xml.bind.annotation.XmlAttribute',
     'javax.xml.bind.annotation.XmlElement',
     'javax.xml.bind.annotation.XmlElement$DEFAULT',
@@ -158,24 +159,41 @@ thirdPartyAudit {
     'javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter',
     'javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter$DEFAULT',
     'javax.xml.bind.annotation.adapters.XmlJavaTypeAdapters',
-    'kotlin.collections.ArraysKt',
-    'kotlin.jvm.JvmClassMappingKt',
-    'kotlin.jvm.functions.Function0',
-    'kotlin.jvm.functions.Function1',
-    'kotlin.jvm.internal.FunctionReference',
-    'kotlin.jvm.internal.Intrinsics',
-    'kotlin.jvm.internal.Reflection',
-    'kotlin.jvm.internal.markers.KMappedMarker',
-    'kotlin.reflect.KClass',
-    'kotlin.reflect.KDeclarationContainer',
-    'kotlin.sequences.Sequence',
     'org.osgi.framework.BundleActivator',
     'org.osgi.framework.BundleContext',
     'org.slf4j.impl.StaticLoggerBinder',
     'org.slf4j.impl.StaticMDCBinder',
     'org.slf4j.impl.StaticMarkerBinder',
     'reactor.blockhound.BlockHound$Builder',
-    'reactor.blockhound.integration.BlockHoundIntegration'
+    'reactor.blockhound.integration.BlockHoundIntegration',
+    'io.micrometer.context.ContextRegistry',
+    'io.micrometer.context.ContextSnapshot',
+    'io.micrometer.context.ContextSnapshot$Scope',
+    'io.micrometer.context.ThreadLocalAccessor',
+    'io.micrometer.common.KeyValue',
+    'io.micrometer.common.KeyValues',
+    'io.micrometer.common.docs.KeyName',
+    'io.micrometer.core.instrument.Meter$Type',
+    'io.micrometer.core.instrument.docs.MeterDocumentation',
+    'io.micrometer.observation.Observation',
+    'io.micrometer.observation.Observation$Context',
+    'io.micrometer.observation.docs.ObservationDocumentation',
+    'io.micrometer.observation.transport.ReceiverContext',
+    'io.micrometer.observation.transport.RequestReplyReceiverContext',
+    'io.micrometer.observation.transport.RequestReplySenderContext',
+    'io.micrometer.observation.transport.SenderContext',
+    'io.micrometer.tracing.Span',
+    'io.micrometer.tracing.Tracer',
+    'io.micrometer.tracing.docs.SpanDocumentation',
+    'io.micrometer.tracing.handler.PropagatingReceiverTracingObservationHandler',
+    'io.micrometer.tracing.handler.PropagatingSenderTracingObservationHandler',
+    'io.micrometer.tracing.propagation.Propagator',
+    'io.micrometer.context.ContextAccessor',
+    'io.micrometer.core.instrument.observation.MeterObservationHandler',
+    'io.micrometer.observation.ObservationHandler',
+    'io.micrometer.observation.ObservationRegistry',
+    'io.micrometer.observation.ObservationRegistry$ObservationConfig',
+    'io.micrometer.tracing.handler.DefaultTracingObservationHandler'
   )
 
   ignoreViolations(
@@ -188,7 +206,6 @@ thirdPartyAudit {
     'com.google.common.hash.Striped64$Cell',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$2',
-    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$3',
     'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper',
     'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
diff --git a/plugins/repository-azure/licenses/azure-core-1.26.0.jar.sha1 b/plugins/repository-azure/licenses/azure-core-1.26.0.jar.sha1
deleted file mode 100644
index 693c6a721959c..0000000000000
--- a/plugins/repository-azure/licenses/azure-core-1.26.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-461b89dcf8948a0c4a97d4f1d876f778d0cac7aa
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-core-1.39.0.jar.sha1 b/plugins/repository-azure/licenses/azure-core-1.39.0.jar.sha1
new file mode 100644
index 0000000000000..c91498a464b3d
--- /dev/null
+++ b/plugins/repository-azure/licenses/azure-core-1.39.0.jar.sha1
@@ -0,0 +1 @@
+39765fb88a90174628b31ddf6ff9f8d63462e080
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-core-http-netty-1.11.8.jar.sha1 b/plugins/repository-azure/licenses/azure-core-http-netty-1.11.8.jar.sha1
deleted file mode 100644
index df7d7ae4ce285..0000000000000
--- a/plugins/repository-azure/licenses/azure-core-http-netty-1.11.8.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0ea66d4531fb41cb3b5ab55e2e7b7f301e7f8503
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-core-http-netty-1.12.8.jar.sha1 b/plugins/repository-azure/licenses/azure-core-http-netty-1.12.8.jar.sha1
new file mode 100644
index 0000000000000..e6ee1dec64641
--- /dev/null
+++ b/plugins/repository-azure/licenses/azure-core-http-netty-1.12.8.jar.sha1
@@ -0,0 +1 @@
+511ed2d02afb0f43f029df3d10ff80d2d3539f05
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-json-1.0.1.jar.sha1 b/plugins/repository-azure/licenses/azure-json-1.0.1.jar.sha1
new file mode 100644
index 0000000000000..128a82717fef9
--- /dev/null
+++ b/plugins/repository-azure/licenses/azure-json-1.0.1.jar.sha1
@@ -0,0 +1 @@
+abdfdb0c49eebe75ed8532d047dea0c9f13c30ac
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-storage-blob-12.14.4.jar.sha1 b/plugins/repository-azure/licenses/azure-storage-blob-12.14.4.jar.sha1
deleted file mode 100644
index 5333f8fa90ada..0000000000000
--- a/plugins/repository-azure/licenses/azure-storage-blob-12.14.4.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-2b92020693d09e4980b96d278e8038a1087afea0
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-storage-blob-12.23.0.jar.sha1 b/plugins/repository-azure/licenses/azure-storage-blob-12.23.0.jar.sha1
new file mode 100644
index 0000000000000..5f32d64b00918
--- /dev/null
+++ b/plugins/repository-azure/licenses/azure-storage-blob-12.23.0.jar.sha1
@@ -0,0 +1 @@
+3eeb49d5109e812343fb436e4bbb2eecac8fe386
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-storage-common-12.15.0.jar.sha1 b/plugins/repository-azure/licenses/azure-storage-common-12.15.0.jar.sha1
deleted file mode 100644
index 1f3adfc161c7f..0000000000000
--- a/plugins/repository-azure/licenses/azure-storage-common-12.15.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4d63ce8bbd20379c5e5262b1204ceac7b31a7743
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/azure-storage-common-12.21.1.jar.sha1 b/plugins/repository-azure/licenses/azure-storage-common-12.21.1.jar.sha1
new file mode 100644
index 0000000000000..97baa70f28f05
--- /dev/null
+++ b/plugins/repository-azure/licenses/azure-storage-common-12.21.1.jar.sha1
@@ -0,0 +1 @@
+3dd1e186f4e0815eb9f5c1a5bf3090ff4467a03a
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/commons-lang3-3.12.0.jar.sha1 b/plugins/repository-azure/licenses/commons-lang3-3.12.0.jar.sha1
deleted file mode 100644
index 9273d8c01aaba..0000000000000
--- a/plugins/repository-azure/licenses/commons-lang3-3.12.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c6842c86792ff03b9f1d1fe2aab8dc23aa6c6f0e
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/commons-lang3-3.13.0.jar.sha1 b/plugins/repository-azure/licenses/commons-lang3-3.13.0.jar.sha1
new file mode 100644
index 0000000000000..d0c2f2486ee1f
--- /dev/null
+++ b/plugins/repository-azure/licenses/commons-lang3-3.13.0.jar.sha1
@@ -0,0 +1 @@
+b7263237aa89c1f99b327197c41d0669707a462e
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/commons-lang3-NOTICE.txt b/plugins/repository-azure/licenses/commons-lang3-NOTICE.txt
index 078282451b679..13a3140897472 100644
--- a/plugins/repository-azure/licenses/commons-lang3-NOTICE.txt
+++ b/plugins/repository-azure/licenses/commons-lang3-NOTICE.txt
@@ -1,8 +1,5 @@
 Apache Commons Lang
-Copyright 2001-2014 The Apache Software Foundation
+Copyright 2001-2019 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
-
-This product includes software from the Spring Framework,
-under the Apache License 2.0 (see: StringUtils.containsWhitespace())
diff --git a/plugins/repository-azure/licenses/guava-31.1-jre.jar.sha1 b/plugins/repository-azure/licenses/guava-31.1-jre.jar.sha1
deleted file mode 100644
index e57390ebe1299..0000000000000
--- a/plugins/repository-azure/licenses/guava-31.1-jre.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-60458f877d055d0c9114d9e1a2efb737b4bc282c
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/guava-32.1.1-jre.jar.sha1 b/plugins/repository-azure/licenses/guava-32.1.1-jre.jar.sha1
new file mode 100644
index 0000000000000..0d791b5d3f55b
--- /dev/null
+++ b/plugins/repository-azure/licenses/guava-32.1.1-jre.jar.sha1
@@ -0,0 +1 @@
+ad575652d84153075dd41ec6177ccb15251262b2
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-LICENSE.txt b/plugins/repository-azure/licenses/jackson-LICENSE.txt
new file mode 100644
index 0000000000000..f5f45d26a49d6
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-LICENSE.txt
@@ -0,0 +1,8 @@
+This copy of Jackson JSON processor streaming parser/generator is licensed under the
+Apache (Software) License, version 2.0 ("the License").
+See the License for details about distribution rights, and the
+specific rights regarding derivate works.
+
+You may obtain a copy of the License at:
+
+http://www.apache.org/licenses/LICENSE-2.0
diff --git a/plugins/repository-azure/licenses/jackson-NOTICE.txt b/plugins/repository-azure/licenses/jackson-NOTICE.txt
new file mode 100644
index 0000000000000..4c976b7b4cc58
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-NOTICE.txt
@@ -0,0 +1,20 @@
+# Jackson JSON processor
+
+Jackson is a high-performance, Free/Open Source JSON processing library.
+It was originally written by Tatu Saloranta (tatu.saloranta@iki.fi), and has
+been in development since 2007.
+It is currently developed by a community of developers, as well as supported
+commercially by FasterXML.com.
+
+## Licensing
+
+Jackson core and extension components may licensed under different licenses.
+To find the details that apply to this artifact see the accompanying LICENSE file.
+For more information, including possible other licensing options, contact
+FasterXML.com (http://fasterxml.com).
+
+## Credits
+
+A list of contributors may be found from CREDITS file, which is included
+in some artifacts (usually source distributions); but is always available
+from the source code management (SCM) system project uses.
diff --git a/plugins/repository-azure/licenses/jackson-annotations-2.13.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-annotations-2.13.2.jar.sha1
deleted file mode 100644
index ecd3fb49d5b12..0000000000000
--- a/plugins/repository-azure/licenses/jackson-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ec18851f1976d5b810ae1a5fcc32520d2d38f77a
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-annotations-2.15.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-databind-2.13.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/plugins/repository-azure/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-databind-2.15.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-dataformat-xml-2.13.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-dataformat-xml-2.13.2.jar.sha1
deleted file mode 100644
index 7d020f81a91ba..0000000000000
--- a/plugins/repository-azure/licenses/jackson-dataformat-xml-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-cb6a722f128ff0ce2494384d419b6ff20fad25ab
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-dataformat-xml-2.15.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-dataformat-xml-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..18c388b84f333
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-dataformat-xml-2.15.2.jar.sha1
@@ -0,0 +1 @@
+e7e9038dee5c1adb1ebd07d3669e0e1182ac5b60
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.13.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.13.2.jar.sha1
deleted file mode 100644
index 979d38bb38784..0000000000000
--- a/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-cddd9380efd4b81ea01e98be8fbdc9765a81793b
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.15.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..6aa4f9b99c274
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-datatype-jsr310-2.15.2.jar.sha1
@@ -0,0 +1 @@
+30d16ec2aef6d8094c5e2dce1d95034ca8b6cb42
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.13.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.13.2.jar.sha1
deleted file mode 100644
index c71c4fe5ee90c..0000000000000
--- a/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e2f198c512f0f0ccbd6d618baecc9dde9975eadf
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.15.2.jar.sha1 b/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..80da08928f855
--- /dev/null
+++ b/plugins/repository-azure/licenses/jackson-module-jaxb-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+6a22fd1c7b0f9788e81eea32c11dc8c1ba421f18
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-dns-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-dns-4.1.73.Final.jar.sha1
deleted file mode 100644
index 320ae18c98bda..0000000000000
--- a/plugins/repository-azure/licenses/netty-codec-dns-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-46137a5b01a5202059324cf4300443e53f11a38d
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-dns-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-dns-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6c1112ed49775
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-codec-dns-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+21c76a42a468faafac6c84f8aca775073fc8e345
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-http2-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-http2-4.1.73.Final.jar.sha1
deleted file mode 100644
index d7f5a464bcc00..0000000000000
--- a/plugins/repository-azure/licenses/netty-codec-http2-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0eb145bc31fd32a20fd2a3e8b30736d2e0248b0c
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-http2-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-http2-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..f9bdefc6dd965
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-codec-http2-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+c5a3481c4bb9732a3a94fb63cf916141a1a14669
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-socks-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-socks-4.1.73.Final.jar.sha1
deleted file mode 100644
index 6ba41c576c93d..0000000000000
--- a/plugins/repository-azure/licenses/netty-codec-socks-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-cefa44d8f5dcaab21179d945f12b6c6d7325cce9
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-codec-socks-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-codec-socks-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..717703c36e1ab
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-codec-socks-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+259bf1c5178c3e23bb89a2fab59b6d22846e3fa6
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-handler-proxy-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-handler-proxy-4.1.73.Final.jar.sha1
deleted file mode 100644
index f50c9abf023cf..0000000000000
--- a/plugins/repository-azure/licenses/netty-handler-proxy-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d1afa6876c3d3bdbdbe5127ddd495e6514d6e600
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-handler-proxy-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-handler-proxy-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..3f69ae54c5d4a
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-handler-proxy-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+8c8a89ea89b06e120c57bdb3db14b9a47ca30bb3
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-resolver-dns-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-resolver-dns-4.1.73.Final.jar.sha1
deleted file mode 100644
index 817fa4cc0d86f..0000000000000
--- a/plugins/repository-azure/licenses/netty-resolver-dns-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-97cdf5fb97f8d961cfa3ffb05175009b90e5cfee
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-resolver-dns-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-resolver-dns-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..adef44a4e7da7
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-resolver-dns-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+804d8b752847923d3bb81f24de604597047c9b2e
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.73.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.73.Final.jar.sha1
deleted file mode 100644
index 22b8f58bd5103..0000000000000
--- a/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4701063d36f390e02da6da85c13e32a0e78349d2
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1 b/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6b7b66ea768e3
--- /dev/null
+++ b/plugins/repository-azure/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+cb0fc6c31c387404212949c57950b5d72ce908b9
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-core-3.4.15.jar.sha1 b/plugins/repository-azure/licenses/reactor-core-3.4.15.jar.sha1
deleted file mode 100644
index a89de48b20b51..0000000000000
--- a/plugins/repository-azure/licenses/reactor-core-3.4.15.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-28ccf513fe64709c8ded30ea3f387fc718db9626
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-core-3.5.6.jar.sha1 b/plugins/repository-azure/licenses/reactor-core-3.5.6.jar.sha1
new file mode 100644
index 0000000000000..ad9b7263e7b38
--- /dev/null
+++ b/plugins/repository-azure/licenses/reactor-core-3.5.6.jar.sha1
@@ -0,0 +1 @@
+027fdc551537b349389176a23a192f11a7a3d7de
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-1.0.16.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-1.0.16.jar.sha1
deleted file mode 100644
index 582380e449a1d..0000000000000
--- a/plugins/repository-azure/licenses/reactor-netty-1.0.16.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d90829f6127966b0c35c4a3e8e23ca9ed29cd8a5
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-1.1.8.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-1.1.8.jar.sha1
new file mode 100644
index 0000000000000..6b6bf1903b16c
--- /dev/null
+++ b/plugins/repository-azure/licenses/reactor-netty-1.1.8.jar.sha1
@@ -0,0 +1 @@
+d53a9d7d0395285f4c81664494fcd61477626e32
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-core-1.0.16.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-core-1.0.16.jar.sha1
deleted file mode 100644
index 0d1a0cb20c80f..0000000000000
--- a/plugins/repository-azure/licenses/reactor-netty-core-1.0.16.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8f842a912677f2bc614ff60fb9e786d4fa429c34
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-core-1.1.8.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-core-1.1.8.jar.sha1
new file mode 100644
index 0000000000000..707631f4dfe0c
--- /dev/null
+++ b/plugins/repository-azure/licenses/reactor-netty-core-1.1.8.jar.sha1
@@ -0,0 +1 @@
+48999c4ae27cdcee5eaff9dfd150a8b64624f0f5
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-http-1.0.16.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-http-1.0.16.jar.sha1
deleted file mode 100644
index d737315b06b62..0000000000000
--- a/plugins/repository-azure/licenses/reactor-netty-http-1.0.16.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-93edb9a1dc774d843551a616e0f316e11ffa81ed
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/reactor-netty-http-1.1.9.jar.sha1 b/plugins/repository-azure/licenses/reactor-netty-http-1.1.9.jar.sha1
new file mode 100644
index 0000000000000..96deead2c75d1
--- /dev/null
+++ b/plugins/repository-azure/licenses/reactor-netty-http-1.1.9.jar.sha1
@@ -0,0 +1 @@
+408b3037133f2e8ab0f195ccd3f807026be9b860
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/slf4j-api-1.6.2.jar.sha1 b/plugins/repository-azure/licenses/slf4j-api-1.6.2.jar.sha1
deleted file mode 100644
index a2f93ea55802b..0000000000000
--- a/plugins/repository-azure/licenses/slf4j-api-1.6.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8619e95939167fb37245b5670135e4feb0ec7d50
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/repository-azure/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/repository-azure/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/woodstox-core-6.2.8.jar.sha1 b/plugins/repository-azure/licenses/woodstox-core-6.2.8.jar.sha1
deleted file mode 100644
index ae65cdebf26de..0000000000000
--- a/plugins/repository-azure/licenses/woodstox-core-6.2.8.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-670748292899c53b1963730d9eb7f8ab71314e90
\ No newline at end of file
diff --git a/plugins/repository-azure/licenses/woodstox-core-6.4.0.jar.sha1 b/plugins/repository-azure/licenses/woodstox-core-6.4.0.jar.sha1
new file mode 100644
index 0000000000000..cac5f37205956
--- /dev/null
+++ b/plugins/repository-azure/licenses/woodstox-core-6.4.0.jar.sha1
@@ -0,0 +1 @@
+c47579857bbf12c85499f431d4ecf27d77976b7c
\ No newline at end of file
diff --git a/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureBlobStoreRepositoryTests.java b/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureBlobStoreRepositoryTests.java
index 4b11f2e3305e6..82364d1b7b3c1 100644
--- a/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureBlobStoreRepositoryTests.java
+++ b/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureBlobStoreRepositoryTests.java
@@ -31,25 +31,23 @@
 
 package org.opensearch.repositories.azure;
 
-import com.azure.storage.blob.models.ParallelTransferOptions;
-import com.azure.storage.common.implementation.Constants;
-import com.azure.storage.common.policy.RequestRetryOptions;
-import com.azure.storage.common.policy.RetryPolicyType;
 import com.sun.net.httpserver.Headers;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
-import fixture.azure.AzureHttpHandler;
-import reactor.core.scheduler.Schedulers;
 
-import org.junit.AfterClass;
+import com.azure.storage.blob.models.ParallelTransferOptions;
+import com.azure.storage.common.implementation.Constants;
+import com.azure.storage.common.policy.RequestRetryOptions;
+import com.azure.storage.common.policy.RetryPolicyType;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.blobstore.OpenSearchMockAPIBasedRepositoryIntegTestCase;
-import org.opensearch.rest.RestStatus;
+import org.junit.AfterClass;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -59,6 +57,9 @@
 import java.util.Map;
 import java.util.regex.Pattern;
 
+import fixture.azure.AzureHttpHandler;
+import reactor.core.scheduler.Schedulers;
+
 @SuppressForbidden(reason = "this test uses a HttpServer to emulate an Azure endpoint")
 public class AzureBlobStoreRepositoryTests extends OpenSearchMockAPIBasedRepositoryIntegTestCase {
     @AfterClass
diff --git a/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureStorageCleanupThirdPartyTests.java b/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureStorageCleanupThirdPartyTests.java
index 6d71a65a35a4c..176e60a667aef 100644
--- a/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureStorageCleanupThirdPartyTests.java
+++ b/plugins/repository-azure/src/internalClusterTest/java/org/opensearch/repositories/azure/AzureStorageCleanupThirdPartyTests.java
@@ -32,30 +32,29 @@
 
 package org.opensearch.repositories.azure;
 
-import reactor.core.scheduler.Schedulers;
-
 import com.azure.core.util.Context;
 import com.azure.storage.blob.BlobContainerClient;
 import com.azure.storage.blob.BlobServiceClient;
 import com.azure.storage.blob.models.BlobStorageException;
-
-import org.junit.AfterClass;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.SecureSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.AbstractThirdPartyRepositoryTestCase;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.junit.AfterClass;
 
 import java.net.HttpURLConnection;
 import java.util.Collection;
 import java.util.function.Supplier;
 
+import reactor.core.scheduler.Schedulers;
+
 import static org.hamcrest.Matchers.blankOrNullString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobContainer.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobContainer.java
index d6fa72221f408..2b4654d220061 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobContainer.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobContainer.java
@@ -35,10 +35,8 @@
 import com.azure.storage.blob.models.BlobStorageException;
 import com.azure.storage.blob.specialized.BlobInputStream;
 import com.azure.storage.common.implementation.Constants;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.action.support.PlainActionFuture;
@@ -48,6 +46,7 @@
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.DeleteResult;
 import org.opensearch.common.blobstore.support.AbstractBlobContainer;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.FileInputStream;
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobStore.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobStore.java
index b540dd83c95a2..e76a6bdd16764 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobStore.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureBlobStore.java
@@ -50,7 +50,6 @@
 import com.azure.storage.blob.models.ListBlobsOptions;
 import com.azure.storage.blob.options.BlobParallelUploadOptions;
 import com.azure.storage.common.implementation.Constants;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.util.Throwables;
@@ -442,7 +441,7 @@ private static class Stats {
         private final AtomicLong putBlockListOperations = new AtomicLong();
 
         private Map<String, Long> toMap() {
-            return org.opensearch.common.collect.Map.of(
+            return Map.of(
                 "GetBlob",
                 getOperations.get(),
                 "ListBlobs",
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepository.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepository.java
index a7799fef475f3..47a5536a6cd8a 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepository.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepository.java
@@ -37,16 +37,18 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.blobstore.MeteredBlobStoreRepository;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.function.Function;
@@ -100,8 +102,6 @@ public static final class Repository {
             MAX_CHUNK_SIZE,
             Property.NodeScope
         );
-        public static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", false, Property.NodeScope);
-        public static final Setting<Boolean> READONLY_SETTING = Setting.boolSetting("readonly", false, Property.NodeScope);
     }
 
     private final BlobPath basePath;
@@ -116,14 +116,7 @@ public AzureRepository(
         final ClusterService clusterService,
         final RecoverySettings recoverySettings
     ) {
-        super(
-            metadata,
-            Repository.COMPRESS_SETTING.get(metadata.settings()),
-            namedXContentRegistry,
-            clusterService,
-            recoverySettings,
-            buildLocation(metadata)
-        );
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings, buildLocation(metadata));
         this.chunkSize = Repository.CHUNK_SIZE_SETTING.get(metadata.settings());
         this.storageService = storageService;
 
@@ -142,15 +135,15 @@ public AzureRepository(
         // If the user explicitly did not define a readonly value, we set it by ourselves depending on the location mode setting.
         // For secondary_only setting, the repository should be read only
         final LocationMode locationMode = Repository.LOCATION_MODE_SETTING.get(metadata.settings());
-        if (Repository.READONLY_SETTING.exists(metadata.settings())) {
-            this.readonly = Repository.READONLY_SETTING.get(metadata.settings());
+        if (READONLY_SETTING.exists(metadata.settings())) {
+            this.readonly = READONLY_SETTING.get(metadata.settings());
         } else {
             this.readonly = locationMode == LocationMode.SECONDARY_ONLY;
         }
     }
 
     private static Map<String, String> buildLocation(RepositoryMetadata metadata) {
-        return org.opensearch.common.collect.Map.of(
+        return Map.of(
             "base_path",
             Repository.BASE_PATH_SETTING.get(metadata.settings()),
             "container",
@@ -194,4 +187,13 @@ protected ByteSizeValue chunkSize() {
     public boolean isReadOnly() {
         return readonly;
     }
+
+    @Override
+    public List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        List<Setting<?>> restrictedSettings = new ArrayList<>();
+        restrictedSettings.addAll(super.getRestrictedSystemRepositorySettings());
+        restrictedSettings.add(Repository.BASE_PATH_SETTING);
+        restrictedSettings.add(Repository.LOCATION_MODE_SETTING);
+        return restrictedSettings;
+    }
 }
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepositoryPlugin.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepositoryPlugin.java
index 82ab5243a09aa..78db7cb2d0ea7 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepositoryPlugin.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureRepositoryPlugin.java
@@ -37,7 +37,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageService.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageService.java
index 3800be7c2d27d..9dcc312f8f5a7 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageService.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageService.java
@@ -32,11 +32,6 @@
 
 package org.opensearch.repositories.azure;
 
-import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
-import io.netty.util.concurrent.Future;
-import reactor.core.publisher.Mono;
-
 import com.azure.core.http.HttpPipelineCallContext;
 import com.azure.core.http.HttpPipelineNextPolicy;
 import com.azure.core.http.HttpPipelinePosition;
@@ -56,14 +51,13 @@
 import com.azure.storage.common.implementation.connectionstring.StorageEndpoint;
 import com.azure.storage.common.policy.RequestRetryOptions;
 import com.azure.storage.common.policy.RetryPolicyType;
-
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.net.Authenticator;
 import java.net.PasswordAuthentication;
@@ -79,6 +73,11 @@
 import java.util.function.BiConsumer;
 import java.util.function.Supplier;
 
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.util.concurrent.Future;
+import reactor.core.publisher.Mono;
+
 import static java.util.Collections.emptyMap;
 
 public class AzureStorageService implements AutoCloseable {
@@ -250,7 +249,7 @@ private BlobServiceClientBuilder applyLocationMode(final BlobServiceClientBuilde
 
     private static BlobServiceClientBuilder createClientBuilder(AzureStorageSettings settings) throws InvalidKeyException,
         URISyntaxException {
-        return new BlobServiceClientBuilder().connectionString(settings.getConnectString());
+        return SocketAccess.doPrivilegedException(() -> new BlobServiceClientBuilder().connectionString(settings.getConnectString()));
     }
 
     /**
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageSettings.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageSettings.java
index c9a031451bccd..e73ded679cf2b 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageSettings.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/AzureStorageSettings.java
@@ -33,16 +33,17 @@
 package org.opensearch.repositories.azure;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.AffixSetting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
+
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.Collections;
@@ -91,8 +92,7 @@ final class AzureStorageSettings {
         AZURE_CLIENT_PREFIX_KEY,
         "endpoint_suffix",
         key -> Setting.simpleString(key, Property.NodeScope),
-        () -> ACCOUNT_SETTING,
-        () -> KEY_SETTING
+        () -> ACCOUNT_SETTING
     );
 
     // The overall operation timeout
diff --git a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/ProxySettings.java b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/ProxySettings.java
index df8c95e69acf2..03097626c9741 100644
--- a/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/ProxySettings.java
+++ b/plugins/repository-azure/src/main/java/org/opensearch/repositories/azure/ProxySettings.java
@@ -9,8 +9,8 @@
 package org.opensearch.repositories.azure;
 
 import com.azure.core.http.ProxyOptions;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.Strings;
 
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
diff --git a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureBlobContainerRetriesTests.java b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureBlobContainerRetriesTests.java
index c9e6e299c7120..5117768aa3351 100644
--- a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureBlobContainerRetriesTests.java
+++ b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureBlobContainerRetriesTests.java
@@ -31,23 +31,18 @@
 
 package org.opensearch.repositories.azure;
 
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpServer;
+
 import com.azure.storage.blob.BlobClient;
 import com.azure.storage.blob.models.ParallelTransferOptions;
 import com.azure.storage.common.policy.RequestRetryOptions;
 import com.azure.storage.common.policy.RetryPolicyType;
-import com.sun.net.httpserver.HttpExchange;
-import com.sun.net.httpserver.HttpServer;
-import fixture.azure.AzureHttpHandler;
-import reactor.core.scheduler.Schedulers;
-
 import org.apache.http.HttpStatus;
-
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
@@ -55,15 +50,16 @@
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
-
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -91,6 +87,9 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import fixture.azure.AzureHttpHandler;
+import reactor.core.scheduler.Schedulers;
+
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.opensearch.repositories.azure.AzureRepository.Repository.CONTAINER_SETTING;
 import static org.opensearch.repositories.azure.AzureStorageSettings.ACCOUNT_SETTING;
@@ -122,6 +121,10 @@ public class AzureBlobContainerRetriesTests extends OpenSearchTestCase {
     public void setUp() throws Exception {
         threadPool = new TestThreadPool(getTestClass().getName(), AzureRepositoryPlugin.executorBuilder());
         httpServer = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        httpServer.createContext("/", (exchange) -> {
+            exchange.sendResponseHeaders(404, 0L);
+            exchange.close();
+        });
         httpServer.start();
         super.setUp();
     }
@@ -231,6 +234,7 @@ public void testReadBlobWithRetries() throws Exception {
                         exchange.getResponseHeaders().add("Content-Type", "application/octet-stream");
                         exchange.getResponseHeaders().add("Content-Length", String.valueOf(length));
                         exchange.getResponseHeaders().add("x-ms-blob-type", "blockblob");
+                        exchange.getResponseHeaders().add("Content-Range", "bytes " + rangeStart + "-" + bytes.length + "/" + bytes.length);
                         exchange.sendResponseHeaders(RestStatus.OK.getStatus(), length);
                         exchange.getResponseBody().write(bytes, rangeStart, length);
                         return;
@@ -247,7 +251,8 @@ public void testReadBlobWithRetries() throws Exception {
         final BlobContainer blobContainer = createBlobContainer(maxRetries);
         try (InputStream inputStream = blobContainer.readBlob("read_blob_max_retries")) {
             assertArrayEquals(bytes, BytesReference.toBytes(Streams.readFully(inputStream)));
-            assertThat(countDownHead.isCountedDown(), is(true));
+            // No more getProperties() calls in BlobClientBase::openInputStream(), HEAD should not be invoked
+            assertThat(countDownHead.isCountedDown(), is(false));
             assertThat(countDownGet.isCountedDown(), is(true));
         }
     }
@@ -278,6 +283,8 @@ public void testReadRangeBlobWithRetries() throws Exception {
                         assertThat(length, lessThanOrEqualTo(bytes.length - rangeStart));
                         exchange.getResponseHeaders().add("Content-Type", "application/octet-stream");
                         exchange.getResponseHeaders().add("Content-Length", String.valueOf(length));
+                        exchange.getResponseHeaders()
+                            .add("Content-Range", "bytes " + rangeStart + "-" + rangeEnd.get() + "/" + bytes.length);
                         exchange.getResponseHeaders().add("x-ms-blob-type", "blockblob");
                         exchange.sendResponseHeaders(RestStatus.OK.getStatus(), length);
                         exchange.getResponseBody().write(bytes, rangeStart, length);
diff --git a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureRepositorySettingsTests.java b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureRepositorySettingsTests.java
index 01235d6193d9c..3356e5174592a 100644
--- a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureRepositorySettingsTests.java
+++ b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureRepositorySettingsTests.java
@@ -32,19 +32,23 @@
 
 package org.opensearch.repositories.azure;
 
-import reactor.core.scheduler.Schedulers;
-
-import org.junit.AfterClass;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.AfterClass;
+
+import java.util.List;
+
+import reactor.core.scheduler.Schedulers;
 
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
@@ -179,4 +183,21 @@ public void testChunkSize() {
         );
     }
 
+    public void testSystemRepositoryDefault() {
+        assertThat(azureRepository(Settings.EMPTY).isSystemRepository(), is(false));
+    }
+
+    public void testSystemRepositoryOn() {
+        assertThat(azureRepository(Settings.builder().put("system_repository", true).build()).isSystemRepository(), is(true));
+    }
+
+    public void testRestrictedSettingsDefault() {
+        List<Setting<?>> restrictedSettings = azureRepository(Settings.EMPTY).getRestrictedSystemRepositorySettings();
+        assertThat(restrictedSettings.size(), is(5));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.READONLY_SETTING));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY));
+        assertTrue(restrictedSettings.contains(AzureRepository.Repository.BASE_PATH_SETTING));
+        assertTrue(restrictedSettings.contains(AzureRepository.Repository.LOCATION_MODE_SETTING));
+    }
 }
diff --git a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureStorageServiceTests.java b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureStorageServiceTests.java
index 7f5ca73a507ad..264888bb7da3a 100644
--- a/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureStorageServiceTests.java
+++ b/plugins/repository-azure/src/test/java/org/opensearch/repositories/azure/AzureStorageServiceTests.java
@@ -32,20 +32,17 @@
 
 package org.opensearch.repositories.azure;
 
-import org.opensearch.common.Strings;
-import reactor.core.scheduler.Schedulers;
-
 import com.azure.core.http.policy.HttpPipelinePolicy;
 import com.azure.storage.blob.BlobServiceClient;
 import com.azure.storage.common.policy.RequestRetryPolicy;
-
-import org.junit.AfterClass;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.settings.SettingsModule;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.AfterClass;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -60,6 +57,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import reactor.core.scheduler.Schedulers;
+
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.emptyString;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/plugins/repository-azure/src/yamlRestTest/java/org/opensearch/repositories/azure/RepositoryAzureClientYamlTestSuiteIT.java b/plugins/repository-azure/src/yamlRestTest/java/org/opensearch/repositories/azure/RepositoryAzureClientYamlTestSuiteIT.java
index 7ce28855417c3..31ecd60602aa7 100644
--- a/plugins/repository-azure/src/yamlRestTest/java/org/opensearch/repositories/azure/RepositoryAzureClientYamlTestSuiteIT.java
+++ b/plugins/repository-azure/src/yamlRestTest/java/org/opensearch/repositories/azure/RepositoryAzureClientYamlTestSuiteIT.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.annotations.Name;
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
 
diff --git a/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/10_basic.yml b/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/10_basic.yml
index fe21a295e37bb..caec0a89101b4 100644
--- a/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/10_basic.yml
+++ b/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: repository-azure } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: repository-azure } }
diff --git a/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/20_repository.yml b/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/20_repository.yml
index beaa95b732d52..04ff4e8c34033 100644
--- a/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/20_repository.yml
+++ b/plugins/repository-azure/src/yamlRestTest/resources/rest-api-spec/test/repository_azure/20_repository.yml
@@ -29,6 +29,9 @@ setup:
 ---
 "Snapshot/Restore with repository-azure":
 
+  - skip:
+      features: allowed_warnings
+
   # Get repository
   - do:
       snapshot.get_repository:
@@ -169,12 +172,16 @@ setup:
 
   # Remove the snapshots
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       snapshot.delete:
         repository: repository
         snapshot: snapshot-two
         master_timeout: 5m
 
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       snapshot.delete:
         repository: repository
         snapshot: snapshot-one
diff --git a/plugins/repository-gcs/build.gradle b/plugins/repository-gcs/build.gradle
index e1ecf3c65a0f9..95070d04b3bf9 100644
--- a/plugins/repository-gcs/build.gradle
+++ b/plugins/repository-gcs/build.gradle
@@ -9,14 +9,12 @@
  * GitHub history for details.
  */
 
-import java.nio.file.Files
-import java.security.KeyPair
-import java.security.KeyPairGenerator
+
 import org.opensearch.gradle.MavenFilteringHack
 import org.opensearch.gradle.info.BuildParams
+import org.opensearch.gradle.test.InternalClusterTestPlugin
 import org.opensearch.gradle.test.RestIntegTestTask
 import org.opensearch.gradle.test.rest.YamlRestTestPlugin
-import org.opensearch.gradle.test.InternalClusterTestPlugin
 
 import java.nio.file.Files
 import java.security.KeyPair
@@ -49,36 +47,48 @@ opensearchplugin {
   classname 'org.opensearch.repositories.gcs.GoogleCloudStoragePlugin'
 }
 
+versions << [
+  'google_auth': '1.7.0'
+]
+
 dependencies {
-  api 'com.google.cloud:google-cloud-storage:1.113.1'
+  api 'com.google.api:api-common:1.8.1'
+  api 'com.google.api:gax:2.27.0'
+  api 'com.google.api:gax-httpjson:0.103.1'
+
+  api 'com.google.apis:google-api-services-storage:v1-rev20230617-2.0.0'
+
+  api 'com.google.api-client:google-api-client:2.2.0'
+
+  api 'com.google.api.grpc:proto-google-common-protos:2.25.0'
+  api 'com.google.api.grpc:proto-google-iam-v1:0.12.0'
+
+  api "com.google.auth:google-auth-library-credentials:${versions.google_auth}"
+  api "com.google.auth:google-auth-library-oauth2-http:${versions.google_auth}"
+
   api 'com.google.cloud:google-cloud-core:2.5.10'
-  runtimeOnly 'com.google.guava:guava:30.1.1-jre'
+  api 'com.google.cloud:google-cloud-core-http:2.23.0'
+  api 'com.google.cloud:google-cloud-storage:1.113.1'
+
+  api 'com.google.code.gson:gson:2.10.1'
+
+  runtimeOnly "com.google.guava:guava:${versions.guava}"
   api 'com.google.guava:failureaccess:1.0.1'
-  api 'com.google.http-client:google-http-client:1.35.0'
+
+  api 'com.google.http-client:google-http-client:1.43.2'
+  api 'com.google.http-client:google-http-client-appengine:1.43.2'
+  api 'com.google.http-client:google-http-client-gson:1.43.3'
+  api 'com.google.http-client:google-http-client-jackson2:1.43.2'
+
+  api 'com.google.oauth-client:google-oauth-client:1.34.1'
+
   api "commons-logging:commons-logging:${versions.commonslogging}"
   api "org.apache.logging.log4j:log4j-1.2-api:${versions.log4j}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
-  api 'com.google.api:api-common:1.8.1'
-  api 'com.google.api:gax:1.54.0'
   api 'org.threeten:threetenbp:1.4.4'
-  api 'com.google.protobuf:protobuf-java-util:3.19.3'
-  api 'com.google.protobuf:protobuf-java:3.19.3'
-  api 'com.google.code.gson:gson:2.9.0'
-  api 'com.google.api.grpc:proto-google-common-protos:1.16.0'
-  api 'com.google.api.grpc:proto-google-iam-v1:0.12.0'
-  api 'com.google.cloud:google-cloud-core-http:1.93.3'
-  api 'com.google.auth:google-auth-library-credentials:0.20.0'
-  api 'com.google.auth:google-auth-library-oauth2-http:0.20.0'
-  api 'com.google.oauth-client:google-oauth-client:1.31.0'
-  api 'com.google.api-client:google-api-client:1.30.10'
-  api 'com.google.http-client:google-http-client-appengine:1.35.0'
-  api 'com.google.http-client:google-http-client-jackson2:1.35.0'
-  api 'com.google.http-client:google-http-client-gson:1.41.4'
-  api 'com.google.api:gax-httpjson:0.62.0'
-  api 'io.grpc:grpc-context:1.29.0'
-  api 'io.opencensus:opencensus-api:0.18.0'
-  api 'io.opencensus:opencensus-contrib-http-util:0.18.0'
-  api 'com.google.apis:google-api-services-storage:v1-rev20200814-1.30.10'
+  api 'io.grpc:grpc-api:1.57.2'
+  api 'io.opencensus:opencensus-api:0.31.1'
+  api 'io.opencensus:opencensus-contrib-http-util:0.31.1'
 
   testImplementation project(':test:fixtures:gcs-fixture')
 }
@@ -101,13 +111,6 @@ tasks.named("dependencyLicenses").configure {
 thirdPartyAudit {
   ignoreViolations(
     // uses internal java api: sun.misc.Unsafe
-    'com.google.protobuf.UnsafeUtil',
-    'com.google.protobuf.UnsafeUtil$1',
-    'com.google.protobuf.UnsafeUtil$JvmMemoryAccessor',
-    'com.google.protobuf.UnsafeUtil$MemoryAccessor',
-    'com.google.protobuf.MessageSchema',
-    'com.google.protobuf.UnsafeUtil$Android32MemoryAccessor',
-    'com.google.protobuf.UnsafeUtil$Android64MemoryAccessor',
     'com.google.common.cache.Striped64',
     'com.google.common.cache.Striped64$1',
     'com.google.common.cache.Striped64$Cell',
@@ -117,7 +120,6 @@ thirdPartyAudit {
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$2',
-    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$3',
     'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper',
     'com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
@@ -126,6 +128,7 @@ thirdPartyAudit {
   )
 
   ignoreMissingClasses(
+    'com.google.api.client.http.apache.v2.ApacheHttpTransport',
     'com.google.appengine.api.datastore.Blob',
     'com.google.appengine.api.datastore.DatastoreService',
     'com.google.appengine.api.datastore.DatastoreServiceFactory',
@@ -145,6 +148,10 @@ thirdPartyAudit {
     'com.google.appengine.api.urlfetch.HTTPResponse',
     'com.google.appengine.api.urlfetch.URLFetchService',
     'com.google.appengine.api.urlfetch.URLFetchServiceFactory',
+    'com.google.protobuf.util.JsonFormat',
+    'com.google.protobuf.util.JsonFormat$Parser',
+    'com.google.protobuf.util.JsonFormat$Printer',
+    'com.google.protobuf.util.Timestamps',
     // commons-logging optional dependencies
     'org.apache.avalon.framework.logger.Logger',
     'org.apache.log.Hierarchy',
@@ -168,8 +175,8 @@ thirdPartyAudit {
     'org.apache.http.client.UserTokenHandler',
     'org.apache.http.client.methods.HttpEntityEnclosingRequestBase',
     'org.apache.http.client.methods.HttpRequestBase',
-    'org.apache.http.config.SocketConfig',
-    'org.apache.http.config.SocketConfig$Builder',
+    'org.apache.http.config.Registry',
+    'org.apache.http.config.RegistryBuilder',
     'org.apache.http.conn.ClientConnectionManager',
     'org.apache.http.conn.ConnectionKeepAliveStrategy',
     'org.apache.http.conn.params.ConnManagerParams',
@@ -177,6 +184,7 @@ thirdPartyAudit {
     'org.apache.http.conn.routing.HttpRoutePlanner',
     'org.apache.http.conn.scheme.PlainSocketFactory',
     'org.apache.http.conn.scheme.SchemeRegistry',
+    'org.apache.http.conn.socket.PlainConnectionSocketFactory',
     'org.apache.http.conn.ssl.SSLSocketFactory',
     'org.apache.http.conn.ssl.X509HostnameVerifier',
     'org.apache.http.entity.AbstractHttpEntity',
@@ -189,10 +197,15 @@ thirdPartyAudit {
     'org.apache.http.protocol.HttpContext',
     'org.apache.http.protocol.HttpProcessor',
     'org.apache.http.protocol.HttpRequestExecutor',
+    'org.graalvm.nativeimage.hosted.Feature',
+    'org.graalvm.nativeimage.hosted.Feature$BeforeAnalysisAccess',
+    'org.graalvm.nativeimage.hosted.Feature$DuringAnalysisAccess',
+    'org.graalvm.nativeimage.hosted.Feature$FeatureAccess',
+    'org.graalvm.nativeimage.hosted.RuntimeReflection',
     // commons-logging provided dependencies
     'javax.jms.Message',
     'javax.servlet.ServletContextEvent',
-    'javax.servlet.ServletContextListener',
+    'javax.servlet.ServletContextListener'
   )
 }
 
diff --git a/plugins/repository-gcs/licenses/commons-codec-1.13.jar.sha1 b/plugins/repository-gcs/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/repository-gcs/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/commons-codec-1.15.jar.sha1 b/plugins/repository-gcs/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/repository-gcs/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/repository-gcs/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index 5b8f029e58293..0000000000000
--- a/plugins/repository-gcs/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/commons-logging-1.2.jar.sha1 b/plugins/repository-gcs/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/repository-gcs/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/commons-logging-LICENSE.txt b/plugins/repository-gcs/licenses/commons-logging-LICENSE.txt
index 57bc88a15a0ee..d645695673349 100644
--- a/plugins/repository-gcs/licenses/commons-logging-LICENSE.txt
+++ b/plugins/repository-gcs/licenses/commons-logging-LICENSE.txt
@@ -1,3 +1,4 @@
+
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -199,4 +200,3 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
-
diff --git a/plugins/repository-gcs/licenses/commons-logging-NOTICE.txt b/plugins/repository-gcs/licenses/commons-logging-NOTICE.txt
index 72eb32a902458..d3d6e140ce4f3 100644
--- a/plugins/repository-gcs/licenses/commons-logging-NOTICE.txt
+++ b/plugins/repository-gcs/licenses/commons-logging-NOTICE.txt
@@ -1,5 +1,5 @@
-Apache Commons CLI
-Copyright 2001-2009 The Apache Software Foundation
+Apache Commons Logging
+Copyright 2003-2014 The Apache Software Foundation
 
-This product includes software developed by
+This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/repository-gcs/licenses/gax-1.54.0.jar.sha1 b/plugins/repository-gcs/licenses/gax-1.54.0.jar.sha1
deleted file mode 100644
index ed63c084f4edc..0000000000000
--- a/plugins/repository-gcs/licenses/gax-1.54.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1f1668868b8b3fd5fc248d80c16dd9f09afc9180
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/gax-2.27.0.jar.sha1 b/plugins/repository-gcs/licenses/gax-2.27.0.jar.sha1
new file mode 100644
index 0000000000000..1813a3aa94404
--- /dev/null
+++ b/plugins/repository-gcs/licenses/gax-2.27.0.jar.sha1
@@ -0,0 +1 @@
+04a27757c9240da71f896be39f47aaa6e23ef989
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/gax-httpjson-0.103.1.jar.sha1 b/plugins/repository-gcs/licenses/gax-httpjson-0.103.1.jar.sha1
new file mode 100644
index 0000000000000..11315004e233d
--- /dev/null
+++ b/plugins/repository-gcs/licenses/gax-httpjson-0.103.1.jar.sha1
@@ -0,0 +1 @@
+041d99172fda933bc879bdfd8de9420c5c34107e
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/gax-httpjson-0.62.0.jar.sha1 b/plugins/repository-gcs/licenses/gax-httpjson-0.62.0.jar.sha1
deleted file mode 100644
index 161ca85ccfc0c..0000000000000
--- a/plugins/repository-gcs/licenses/gax-httpjson-0.62.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-05a1a4736acd1c4f30304be953532be6aecdc2c9
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-api-client-1.30.10.jar.sha1 b/plugins/repository-gcs/licenses/google-api-client-1.30.10.jar.sha1
deleted file mode 100644
index 62c51887ee1ea..0000000000000
--- a/plugins/repository-gcs/licenses/google-api-client-1.30.10.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-2de98417199785982e1f037fb8b52613f57175ae
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-api-client-2.2.0.jar.sha1 b/plugins/repository-gcs/licenses/google-api-client-2.2.0.jar.sha1
new file mode 100644
index 0000000000000..f9604d6837ca9
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-api-client-2.2.0.jar.sha1
@@ -0,0 +1 @@
+10e53fd4d987e37190432e896bdaa62e8ea2c628
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20200814-1.30.10.jar.sha1 b/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20200814-1.30.10.jar.sha1
deleted file mode 100644
index e399aa5865413..0000000000000
--- a/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20200814-1.30.10.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-fe3b480958961fc7144da10ce3653065d5eb5490
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20230617-2.0.0.jar.sha1 b/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20230617-2.0.0.jar.sha1
new file mode 100644
index 0000000000000..1a1452f773b96
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-api-services-storage-v1-rev20230617-2.0.0.jar.sha1
@@ -0,0 +1 @@
+fc3f225b405303fe7cb760d578348b6b07e7ea8b
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-auth-library-credentials-0.20.0.jar.sha1 b/plugins/repository-gcs/licenses/google-auth-library-credentials-0.20.0.jar.sha1
deleted file mode 100644
index 14cc742737eed..0000000000000
--- a/plugins/repository-gcs/licenses/google-auth-library-credentials-0.20.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-87a91a373e64ba5c3cdf8cc5cf54b189dd1492f8
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-auth-library-credentials-1.7.0.jar.sha1 b/plugins/repository-gcs/licenses/google-auth-library-credentials-1.7.0.jar.sha1
new file mode 100644
index 0000000000000..f2e9a4f7283bf
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-auth-library-credentials-1.7.0.jar.sha1
@@ -0,0 +1 @@
+b29af5a9ea94e9e7f86bded11e39f5afda5b17e8
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-0.20.0.jar.sha1 b/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-0.20.0.jar.sha1
deleted file mode 100644
index 7911c34780cbe..0000000000000
--- a/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-0.20.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f33d4d6c91a68826816606a2208990eea93fcb2a
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-1.7.0.jar.sha1 b/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-1.7.0.jar.sha1
new file mode 100644
index 0000000000000..738645d6b8c7b
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-auth-library-oauth2-http-1.7.0.jar.sha1
@@ -0,0 +1 @@
+985d183303dbd4b7ceb348056e41e59677f6f74f
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-cloud-core-http-1.93.3.jar.sha1 b/plugins/repository-gcs/licenses/google-cloud-core-http-1.93.3.jar.sha1
deleted file mode 100644
index 0518072447569..0000000000000
--- a/plugins/repository-gcs/licenses/google-cloud-core-http-1.93.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-2589aa6a4b6c49811c08ec2803c8e9c79c410bc5
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-cloud-core-http-2.23.0.jar.sha1 b/plugins/repository-gcs/licenses/google-cloud-core-http-2.23.0.jar.sha1
new file mode 100644
index 0000000000000..9db3cbcbec35b
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-cloud-core-http-2.23.0.jar.sha1
@@ -0,0 +1 @@
+9913d0806fcfbfbc4a775f29865126ed8465464b
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-1.35.0.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-1.35.0.jar.sha1
deleted file mode 100644
index 802a6ab3a8d04..0000000000000
--- a/plugins/repository-gcs/licenses/google-http-client-1.35.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f2348dd57d5417c29388bd430f5055dca863c600
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-1.43.2.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-1.43.2.jar.sha1
new file mode 100644
index 0000000000000..a576a74c62542
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-http-client-1.43.2.jar.sha1
@@ -0,0 +1 @@
+2520469ebd8c0675f0d2aeafd2da665228320fcf
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-appengine-1.35.0.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-appengine-1.35.0.jar.sha1
deleted file mode 100644
index 8bf444887d30f..0000000000000
--- a/plugins/repository-gcs/licenses/google-http-client-appengine-1.35.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-394d1e1376538931ec3d4eeed654f9da911b95eb
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-appengine-1.43.2.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-appengine-1.43.2.jar.sha1
new file mode 100644
index 0000000000000..d8a9dba20070b
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-http-client-appengine-1.43.2.jar.sha1
@@ -0,0 +1 @@
+9fb548c5264227813fd83991b94a705b0841c15f
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-gson-1.41.4.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-gson-1.41.4.jar.sha1
deleted file mode 100644
index 17960a99abea2..0000000000000
--- a/plugins/repository-gcs/licenses/google-http-client-gson-1.41.4.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-fa665c1c573765dd858bc34931ad747e4ed11efe
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-gson-1.43.3.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-gson-1.43.3.jar.sha1
new file mode 100644
index 0000000000000..43f4fe4a127e1
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-http-client-gson-1.43.3.jar.sha1
@@ -0,0 +1 @@
+252e267acf720ef6333488740a696a1d5e204639
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-jackson2-1.35.0.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-jackson2-1.35.0.jar.sha1
deleted file mode 100644
index 0342f57779315..0000000000000
--- a/plugins/repository-gcs/licenses/google-http-client-jackson2-1.35.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c1c2a08792b935f3345590783ada872f4a0997f1
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-http-client-jackson2-1.43.2.jar.sha1 b/plugins/repository-gcs/licenses/google-http-client-jackson2-1.43.2.jar.sha1
new file mode 100644
index 0000000000000..7b606a07651ed
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-http-client-jackson2-1.43.2.jar.sha1
@@ -0,0 +1 @@
+5e52a9967ebd8246fc4cca64df5f03608db5ac6e
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-oauth-client-1.31.0.jar.sha1 b/plugins/repository-gcs/licenses/google-oauth-client-1.31.0.jar.sha1
deleted file mode 100644
index 942dbb5d167a4..0000000000000
--- a/plugins/repository-gcs/licenses/google-oauth-client-1.31.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-bf1cfbbaa2497d0a841ea0363df4a61170d5823b
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/google-oauth-client-1.34.1.jar.sha1 b/plugins/repository-gcs/licenses/google-oauth-client-1.34.1.jar.sha1
new file mode 100644
index 0000000000000..a8434bd380761
--- /dev/null
+++ b/plugins/repository-gcs/licenses/google-oauth-client-1.34.1.jar.sha1
@@ -0,0 +1 @@
+4a4f88c5e13143f882268c98239fb85c3b2c6cb2
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/grpc-api-1.57.2.jar.sha1 b/plugins/repository-gcs/licenses/grpc-api-1.57.2.jar.sha1
new file mode 100644
index 0000000000000..8b320fdd2f9cc
--- /dev/null
+++ b/plugins/repository-gcs/licenses/grpc-api-1.57.2.jar.sha1
@@ -0,0 +1 @@
+c71a006b81ddae7bc4b7cb1d2da78c1b173761f4
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/grpc-api-LICENSE.txt b/plugins/repository-gcs/licenses/grpc-api-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-gcs/licenses/grpc-api-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
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+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-gcs/licenses/grpc-api-NOTICE.txt b/plugins/repository-gcs/licenses/grpc-api-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/repository-gcs/licenses/grpc-context-1.29.0.jar.sha1 b/plugins/repository-gcs/licenses/grpc-context-1.29.0.jar.sha1
deleted file mode 100644
index a549827edd283..0000000000000
--- a/plugins/repository-gcs/licenses/grpc-context-1.29.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1d8a441110f86f8927543dc3007639080441ea3c
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/gson-2.10.1.jar.sha1 b/plugins/repository-gcs/licenses/gson-2.10.1.jar.sha1
new file mode 100644
index 0000000000000..9810309d1013a
--- /dev/null
+++ b/plugins/repository-gcs/licenses/gson-2.10.1.jar.sha1
@@ -0,0 +1 @@
+b3add478d4382b78ea20b1671390a858002feb6c
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/gson-2.9.0.jar.sha1 b/plugins/repository-gcs/licenses/gson-2.9.0.jar.sha1
deleted file mode 100644
index 8e9626b0c949b..0000000000000
--- a/plugins/repository-gcs/licenses/gson-2.9.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8a1167e089096758b49f9b34066ef98b2f4b37aa
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/guava-30.1.1-jre.jar.sha1 b/plugins/repository-gcs/licenses/guava-30.1.1-jre.jar.sha1
deleted file mode 100644
index 39e641fc7834f..0000000000000
--- a/plugins/repository-gcs/licenses/guava-30.1.1-jre.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-87e0fd1df874ea3cbe577702fe6f17068b790fd8
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/guava-32.1.1-jre.jar.sha1 b/plugins/repository-gcs/licenses/guava-32.1.1-jre.jar.sha1
new file mode 100644
index 0000000000000..0d791b5d3f55b
--- /dev/null
+++ b/plugins/repository-gcs/licenses/guava-32.1.1-jre.jar.sha1
@@ -0,0 +1 @@
+ad575652d84153075dd41ec6177ccb15251262b2
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/log4j-1.2-api-2.17.1.jar.sha1 b/plugins/repository-gcs/licenses/log4j-1.2-api-2.17.1.jar.sha1
deleted file mode 100644
index 23aa5c60bd596..0000000000000
--- a/plugins/repository-gcs/licenses/log4j-1.2-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-db3a7e7f07e878b92ac4a8f1100bee8325d5713a
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/repository-gcs/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/repository-gcs/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/opencensus-api-0.18.0.jar.sha1 b/plugins/repository-gcs/licenses/opencensus-api-0.18.0.jar.sha1
deleted file mode 100644
index 8b95ab4e4c49c..0000000000000
--- a/plugins/repository-gcs/licenses/opencensus-api-0.18.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-b89a8f8dfd1e1e0d68d83c82a855624814b19a6e
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/opencensus-api-0.31.1.jar.sha1 b/plugins/repository-gcs/licenses/opencensus-api-0.31.1.jar.sha1
new file mode 100644
index 0000000000000..03760848f76ef
--- /dev/null
+++ b/plugins/repository-gcs/licenses/opencensus-api-0.31.1.jar.sha1
@@ -0,0 +1 @@
+66a60c7201c2b8b20ce495f0295b32bb0ccbbc57
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.18.0.jar.sha1 b/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.18.0.jar.sha1
deleted file mode 100644
index 1757e00591110..0000000000000
--- a/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.18.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-76a37e4a931d5801a9e25b0c0353e5f37c4d1e8e
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.31.1.jar.sha1 b/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.31.1.jar.sha1
new file mode 100644
index 0000000000000..4e123da3ab45f
--- /dev/null
+++ b/plugins/repository-gcs/licenses/opencensus-contrib-http-util-0.31.1.jar.sha1
@@ -0,0 +1 @@
+3c13fc5715231fadb16a9b74a44d9d59c460cfa8
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/proto-google-common-protos-1.16.0.jar.sha1 b/plugins/repository-gcs/licenses/proto-google-common-protos-1.16.0.jar.sha1
deleted file mode 100644
index 7762b7a3ebdc3..0000000000000
--- a/plugins/repository-gcs/licenses/proto-google-common-protos-1.16.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-2c5f022ea3b8e8df6a619c4cd8faf9af86022daa
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/proto-google-common-protos-2.25.0.jar.sha1 b/plugins/repository-gcs/licenses/proto-google-common-protos-2.25.0.jar.sha1
new file mode 100644
index 0000000000000..b5ef7ee78e794
--- /dev/null
+++ b/plugins/repository-gcs/licenses/proto-google-common-protos-2.25.0.jar.sha1
@@ -0,0 +1 @@
+adfa7c3d9b806969db75cf35fe4b286b3b8b1ce0
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/protobuf-java-3.19.3.jar.sha1 b/plugins/repository-gcs/licenses/protobuf-java-3.19.3.jar.sha1
deleted file mode 100644
index 655ecd1f1c1c9..0000000000000
--- a/plugins/repository-gcs/licenses/protobuf-java-3.19.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4b57f1b1b9e281231c3fcfc039ce3021e29ff570
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/protobuf-java-util-3.19.3.jar.sha1 b/plugins/repository-gcs/licenses/protobuf-java-util-3.19.3.jar.sha1
deleted file mode 100644
index 9ba36d444c541..0000000000000
--- a/plugins/repository-gcs/licenses/protobuf-java-util-3.19.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3e6812cbbb7e6faffa7b56438740dec510e1fc1a
\ No newline at end of file
diff --git a/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreRepositoryTests.java b/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreRepositoryTests.java
index 4bc59b6ae6553..f8e1a1cc39ae0 100644
--- a/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreRepositoryTests.java
+++ b/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreRepositoryTests.java
@@ -32,33 +32,31 @@
 
 package org.opensearch.repositories.gcs;
 
-import com.google.api.gax.retrying.RetrySettings;
-import com.google.cloud.http.HttpTransportOptions;
-import com.google.cloud.storage.StorageOptions;
 import com.sun.net.httpserver.Headers;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
-import fixture.gcs.FakeOAuth2HttpHandler;
-import fixture.gcs.GoogleCloudStorageHttpHandler;
+
+import com.google.api.gax.retrying.RetrySettings;
+import com.google.cloud.http.HttpTransportOptions;
+import com.google.cloud.storage.StorageOptions;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
@@ -67,9 +65,6 @@
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.OpenSearchMockAPIBasedRepositoryIntegTestCase;
 
-import org.junit.BeforeClass;
-import org.threeten.bp.Duration;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
@@ -80,6 +75,10 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import fixture.gcs.FakeOAuth2HttpHandler;
+import fixture.gcs.GoogleCloudStorageHttpHandler;
+import org.threeten.bp.Duration;
+
 import static org.opensearch.repositories.gcs.GoogleCloudStorageClientSettings.CREDENTIALS_FILE_SETTING;
 import static org.opensearch.repositories.gcs.GoogleCloudStorageClientSettings.ENDPOINT_SETTING;
 import static org.opensearch.repositories.gcs.GoogleCloudStorageClientSettings.TOKEN_URI_SETTING;
@@ -88,22 +87,6 @@
 
 @SuppressForbidden(reason = "this test uses a HttpServer to emulate a Google Cloud Storage endpoint")
 public class GoogleCloudStorageBlobStoreRepositoryTests extends OpenSearchMockAPIBasedRepositoryIntegTestCase {
-
-    public static void assumeNotJava8() {
-        assumeFalse(
-            "This test is flaky on jdk8 - we suspect a JDK bug to trigger some assertion in the HttpServer implementation used "
-                + "to emulate the server side logic of Google Cloud Storage. See https://bugs.openjdk.java.net/browse/JDK-8180754, "
-                + "https://github.com/elastic/elasticsearch/pull/51933 and https://github.com/elastic/elasticsearch/issues/52906 "
-                + "for more background on this issue.",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
-    }
-
-    @BeforeClass
-    public static void skipJava8() {
-        assumeNotJava8();
-    }
-
     @Override
     protected String repositoryType() {
         return GoogleCloudStorageRepository.TYPE;
@@ -148,7 +131,7 @@ protected Settings nodeSettings(int nodeOrdinal) {
 
     public void testDeleteSingleItem() {
         final String repoName = createRepository(randomName());
-        final RepositoriesService repositoriesService = internalCluster().getMasterNodeInstance(RepositoriesService.class);
+        final RepositoriesService repositoriesService = internalCluster().getClusterManagerNodeInstance(RepositoriesService.class);
         final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(repoName);
         PlainActionFuture.get(
             f -> repository.threadPool()
diff --git a/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageThirdPartyTests.java b/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageThirdPartyTests.java
index f1b2f78a37380..1e11b1d111d8f 100644
--- a/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageThirdPartyTests.java
+++ b/plugins/repository-gcs/src/internalClusterTest/java/org/opensearch/repositories/gcs/GoogleCloudStorageThirdPartyTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.repositories.gcs;
 
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.SecureSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.AbstractThirdPartyRepositoryTestCase;
 
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStore.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStore.java
index cd6eb5357ea97..f5c20003ea7b6 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStore.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStore.java
@@ -55,8 +55,8 @@
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
@@ -295,7 +295,7 @@ private void writeBlobResumable(BlobInfo blobInfo, InputStream inputStream, long
                  * It is not enough to wrap the call to Streams#copy, we have to wrap the privileged calls too; this is because Streams#copy
                  * is in the stacktrace and is not granted the permissions needed to close and write the channel.
                  */
-                org.opensearch.core.internal.io.Streams.copy(inputStream, Channels.newOutputStream(new WritableByteChannel() {
+                org.opensearch.common.util.io.Streams.copy(inputStream, Channels.newOutputStream(new WritableByteChannel() {
 
                     @SuppressForbidden(reason = "channel is based on a socket")
                     @Override
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettings.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettings.java
index e8700570d2801..7463bd4ff26fe 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettings.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettings.java
@@ -33,14 +33,13 @@
 
 import com.google.api.services.storage.StorageScopes;
 import com.google.auth.oauth2.ServiceAccountCredentials;
-
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
 
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageHttpStatsCollector.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageHttpStatsCollector.java
index 7375d4edb9030..2f48de94a4830 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageHttpStatsCollector.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageHttpStatsCollector.java
@@ -36,8 +36,8 @@
 import com.google.api.client.http.HttpRequest;
 import com.google.api.client.http.HttpResponse;
 import com.google.api.client.http.HttpResponseInterceptor;
-import org.opensearch.common.collect.List;
 
+import java.util.List;
 import java.util.Locale;
 import java.util.function.Consumer;
 import java.util.function.Function;
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStoragePlugin.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStoragePlugin.java
index 4908b26649b1b..c0fda11b98467 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStoragePlugin.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStoragePlugin.java
@@ -35,7 +35,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRepository.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRepository.java
index 909dc066a493b..f6d078868b875 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRepository.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRepository.java
@@ -36,21 +36,22 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.RepositoryException;
 import org.opensearch.repositories.blobstore.MeteredBlobStoreRepository;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 
 import static org.opensearch.common.settings.Setting.Property;
-import static org.opensearch.common.settings.Setting.boolSetting;
 import static org.opensearch.common.settings.Setting.byteSizeSetting;
 import static org.opensearch.common.settings.Setting.simpleString;
 
@@ -70,7 +71,6 @@ class GoogleCloudStorageRepository extends MeteredBlobStoreRepository {
 
     static final Setting<String> BUCKET = simpleString("bucket", Property.NodeScope, Property.Dynamic);
     static final Setting<String> BASE_PATH = simpleString("base_path", Property.NodeScope, Property.Dynamic);
-    static final Setting<Boolean> COMPRESS = boolSetting("compress", false, Property.NodeScope, Property.Dynamic);
     static final Setting<ByteSizeValue> CHUNK_SIZE = byteSizeSetting(
         "chunk_size",
         MAX_CHUNK_SIZE,
@@ -94,7 +94,7 @@ class GoogleCloudStorageRepository extends MeteredBlobStoreRepository {
         final ClusterService clusterService,
         final RecoverySettings recoverySettings
     ) {
-        super(metadata, getSetting(COMPRESS, metadata), namedXContentRegistry, clusterService, recoverySettings, buildLocation(metadata));
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings, buildLocation(metadata));
         this.storageService = storageService;
 
         String basePath = BASE_PATH.get(metadata.settings());
@@ -115,12 +115,7 @@ class GoogleCloudStorageRepository extends MeteredBlobStoreRepository {
     }
 
     private static Map<String, String> buildLocation(RepositoryMetadata metadata) {
-        return org.opensearch.common.collect.Map.of(
-            "base_path",
-            BASE_PATH.get(metadata.settings()),
-            "bucket",
-            getSetting(BUCKET, metadata)
-        );
+        return Map.of("base_path", BASE_PATH.get(metadata.settings()), "bucket", getSetting(BUCKET, metadata));
     }
 
     @Override
@@ -138,6 +133,15 @@ protected ByteSizeValue chunkSize() {
         return chunkSize;
     }
 
+    @Override
+    public List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        List<Setting<?>> restrictedSettings = new ArrayList<>();
+        restrictedSettings.addAll(super.getRestrictedSystemRepositorySettings());
+        restrictedSettings.add(BUCKET);
+        restrictedSettings.add(BASE_PATH);
+        return restrictedSettings;
+    }
+
     /**
      * Get a given setting from the repository settings, throwing a {@link RepositoryException} if the setting does not exist or is empty.
      */
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRetryingInputStream.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRetryingInputStream.java
index 72d3e37466d09..22926199cd6a2 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRetryingInputStream.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageRetryingInputStream.java
@@ -45,7 +45,7 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.SpecialPermission;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.FilterInputStream;
 import java.io.IOException;
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageService.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageService.java
index f4b501327d52c..445e1d65f3d3e 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageService.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/GoogleCloudStorageService.java
@@ -41,13 +41,12 @@
 import com.google.cloud.http.HttpTransportOptions;
 import com.google.cloud.storage.Storage;
 import com.google.cloud.storage.StorageOptions;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 import java.net.Authenticator;
diff --git a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/ProxySettings.java b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/ProxySettings.java
index ddc6446d2c8c5..11f0cbd83e62e 100644
--- a/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/ProxySettings.java
+++ b/plugins/repository-gcs/src/main/java/org/opensearch/repositories/gcs/ProxySettings.java
@@ -8,7 +8,7 @@
 
 package org.opensearch.repositories.gcs;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
diff --git a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobContainerRetriesTests.java b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobContainerRetriesTests.java
index 6a589126a9466..7ad1c6cf31477 100644
--- a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobContainerRetriesTests.java
+++ b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobContainerRetriesTests.java
@@ -31,23 +31,18 @@
 
 package org.opensearch.repositories.gcs;
 
+import com.sun.net.httpserver.HttpHandler;
+
 import com.google.api.gax.retrying.RetrySettings;
 import com.google.cloud.http.HttpTransportOptions;
 import com.google.cloud.storage.StorageException;
 import com.google.cloud.storage.StorageOptions;
-import com.sun.net.httpserver.HttpHandler;
-import fixture.gcs.FakeOAuth2HttpHandler;
 import org.apache.http.HttpStatus;
-
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
@@ -55,15 +50,16 @@
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.repositories.blobstore.AbstractBlobContainerRetriesTestCase;
 import org.opensearch.repositories.blobstore.OpenSearchMockAPIBasedRepositoryIntegTestCase;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
-import org.junit.BeforeClass;
-import org.threeten.bp.Duration;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -79,10 +75,9 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
-import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeEnd;
-import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeLimit;
-import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeStart;
-import static fixture.gcs.GoogleCloudStorageHttpHandler.parseMultipartRequestBody;
+import fixture.gcs.FakeOAuth2HttpHandler;
+import org.threeten.bp.Duration;
+
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.opensearch.repositories.blobstore.OpenSearchBlobStoreRepositoryIntegTestCase.randomBytes;
 import static org.opensearch.repositories.gcs.GoogleCloudStorageClientSettings.CREDENTIALS_FILE_SETTING;
@@ -97,6 +92,10 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
+import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeEnd;
+import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeLimit;
+import static fixture.gcs.GoogleCloudStorageHttpHandler.getContentRangeStart;
+import static fixture.gcs.GoogleCloudStorageHttpHandler.parseMultipartRequestBody;
 
 @SuppressForbidden(reason = "use a http server")
 public class GoogleCloudStorageBlobContainerRetriesTests extends AbstractBlobContainerRetriesTestCase {
@@ -107,21 +106,6 @@ private String httpServerUrl() {
         return "http://" + InetAddresses.toUriString(address.getAddress()) + ":" + address.getPort();
     }
 
-    public static void assumeNotJava8() {
-        assumeFalse(
-            "This test is flaky on jdk8 - we suspect a JDK bug to trigger some assertion in the HttpServer implementation used "
-                + "to emulate the server side logic of Google Cloud Storage. See https://bugs.openjdk.java.net/browse/JDK-8180754, "
-                + "https://github.com/elastic/elasticsearch/pull/51933 and https://github.com/elastic/elasticsearch/issues/52906 "
-                + "for more background on this issue.",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
-    }
-
-    @BeforeClass
-    public static void skipJava8() {
-        assumeNotJava8();
-    }
-
     @Override
     protected String downloadStorageEndpoint(String blob) {
         return "/download/storage/v1/b/bucket/o/" + blob;
diff --git a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreContainerTests.java b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreContainerTests.java
index 183793049fb8e..1c4e0e4a5a400 100644
--- a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreContainerTests.java
+++ b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageBlobStoreContainerTests.java
@@ -50,11 +50,11 @@
 
 import static org.hamcrest.Matchers.instanceOf;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettingsTests.java b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettingsTests.java
index abf63e5525d4d..dc12456c641ae 100644
--- a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettingsTests.java
+++ b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageClientSettingsTests.java
@@ -33,7 +33,6 @@
 
 import com.google.api.services.storage.StorageScopes;
 import com.google.auth.oauth2.ServiceAccountCredentials;
-
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Setting;
diff --git a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageServiceTests.java b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageServiceTests.java
index c5a3a26be082f..a531555debefb 100644
--- a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageServiceTests.java
+++ b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/GoogleCloudStorageServiceTests.java
@@ -35,14 +35,14 @@
 import com.google.auth.Credentials;
 import com.google.cloud.http.HttpTransportOptions;
 import com.google.cloud.storage.Storage;
-import org.hamcrest.Matchers;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.Matchers;
 
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
@@ -50,9 +50,9 @@
 import java.util.Locale;
 import java.util.UUID;
 
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
-import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 
 public class GoogleCloudStorageServiceTests extends OpenSearchTestCase {
 
diff --git a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/TestUtils.java b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/TestUtils.java
index 44e90fb6b9fea..648955c079b3e 100644
--- a/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/TestUtils.java
+++ b/plugins/repository-gcs/src/test/java/org/opensearch/repositories/gcs/TestUtils.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.repositories.gcs;
 
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.ByteArrayOutputStream;
 import java.security.KeyPairGenerator;
@@ -54,7 +54,7 @@ static byte[] createServiceAccount(final Random random) {
             final String privateKey = Base64.getEncoder().encodeToString(keyPairGenerator.generateKeyPair().getPrivate().getEncoded());
 
             final ByteArrayOutputStream out = new ByteArrayOutputStream();
-            try (XContentBuilder builder = new XContentBuilder(XContentType.JSON.xContent(), out)) {
+            try (XContentBuilder builder = new XContentBuilder(MediaTypeRegistry.JSON.xContent(), out)) {
                 builder.startObject();
                 {
                     builder.field("type", "service_account");
diff --git a/plugins/repository-gcs/src/yamlRestTest/resources/rest-api-spec/test/repository_gcs/10_basic.yml b/plugins/repository-gcs/src/yamlRestTest/resources/rest-api-spec/test/repository_gcs/10_basic.yml
index 072836280b3bc..265b4e2fecfc7 100644
--- a/plugins/repository-gcs/src/yamlRestTest/resources/rest-api-spec/test/repository_gcs/10_basic.yml
+++ b/plugins/repository-gcs/src/yamlRestTest/resources/rest-api-spec/test/repository_gcs/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: repository-gcs } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: repository-gcs } }
diff --git a/plugins/repository-hdfs/build.gradle b/plugins/repository-hdfs/build.gradle
index dc1f55b686044..a5c5015a89a62 100644
--- a/plugins/repository-hdfs/build.gradle
+++ b/plugins/repository-hdfs/build.gradle
@@ -48,7 +48,7 @@ opensearchplugin {
 }
 
 versions << [
-  'hadoop3': '3.3.1'
+  'hadoop3': '3.3.6'
 ]
 
 testFixtures.useFixture ":test:fixtures:krb5kdc-fixture", "hdfs"
@@ -60,30 +60,30 @@ configurations {
 dependencies {
   api "org.apache.hadoop:hadoop-client-api:${versions.hadoop3}"
   runtimeOnly "org.apache.hadoop:hadoop-client-runtime:${versions.hadoop3}"
-  api "org.apache.hadoop:hadoop-hdfs:${versions.hadoop3}"
-  api 'org.apache.htrace:htrace-core4:4.1.0-incubating'
+  api("org.apache.hadoop:hadoop-hdfs:${versions.hadoop3}") {
+    exclude module: 'jetty-server'
+    exclude group: 'org.codehaus.jackson'
+  }
+  api 'org.apache.htrace:htrace-core4:4.2.0-incubating'
   api "org.apache.logging.log4j:log4j-core:${versions.log4j}"
-  api 'org.apache.avro:avro:1.10.2'
-  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
-  api 'com.google.code.gson:gson:2.9.0'
-  runtimeOnly 'com.google.guava:guava:30.1.1-jre'
-  api 'com.google.protobuf:protobuf-java:3.19.3'
+  api 'org.apache.avro:avro:1.11.2'
+  api 'com.google.code.gson:gson:2.10.1'
+  runtimeOnly "com.google.guava:guava:${versions.guava}"
   api "commons-logging:commons-logging:${versions.commonslogging}"
   api 'commons-cli:commons-cli:1.2'
   api "commons-codec:commons-codec:${versions.commonscodec}"
   api 'commons-collections:commons-collections:3.2.2'
-  api 'org.apache.commons:commons-compress:1.21'
-  api 'org.apache.commons:commons-configuration2:2.7'
-  api 'commons-io:commons-io:2.11.0'
-  api 'org.apache.commons:commons-lang3:3.12.0'
-  implementation 'com.google.re2j:re2j:1.1'
+  api "org.apache.commons:commons-compress:${versions.commonscompress}"
+  api 'org.apache.commons:commons-configuration2:2.8.0'
+  api 'commons-io:commons-io:2.12.0'
+  api 'org.apache.commons:commons-lang3:3.13.0'
+  implementation 'com.google.re2j:re2j:1.6'
   api 'javax.servlet:servlet-api:2.5'
   api "org.slf4j:slf4j-api:${versions.slf4j}"
   api "org.apache.logging.log4j:log4j-slf4j-impl:${versions.log4j}"
-  api 'net.minidev:json-smart:2.4.7'
-  api 'org.apache.zookeeper:zookeeper:3.7.0'
+  api 'net.minidev:json-smart:2.4.11'
   api "io.netty:netty-all:${versions.netty}"
-  implementation 'com.fasterxml.woodstox:woodstox-core:6.2.8'
+  implementation "com.fasterxml.woodstox:woodstox-core:${versions.woodstox}"
   implementation 'org.codehaus.woodstox:stax2-api:4.2.1'
 
   hdfsFixture project(':test:fixtures:hdfs-fixture')
@@ -113,19 +113,6 @@ tasks.named("dependencyLicenses").configure {
   mapping from: /hadoop-.*/, to: 'hadoop'
 }
 
-thirdPartyAudit {
-  ignoreViolations(
-    // uses internal java api: sun.misc.Unsafe
-    'com.google.protobuf.MessageSchema',
-    'com.google.protobuf.UnsafeUtil',
-    'com.google.protobuf.UnsafeUtil$1',
-    'com.google.protobuf.UnsafeUtil$Android32MemoryAccessor',
-    'com.google.protobuf.UnsafeUtil$Android64MemoryAccessor',
-    'com.google.protobuf.UnsafeUtil$JvmMemoryAccessor',
-    'com.google.protobuf.UnsafeUtil$MemoryAccessor'
-  )
-}
-
 tasks.named("integTest").configure {
   it.dependsOn(project.tasks.named("bundlePlugin"))
 }
@@ -226,7 +213,8 @@ for (String integTestTaskName : ['integTestHa', 'integTestSecure', 'integTestSec
             .resolve("ports")
         }
         nonInputProperties.systemProperty "test.hdfs-fixture.ports", file("$portsFileDir/ports")
-        classpath += files(portsFileDir)
+        // See please https://docs.gradle.org/8.1/userguide/upgrading_version_8.html#test_task_default_classpath
+        classpath = testing.suites.test.sources.runtimeClasspath + files(portsFileDir)
         // Copy ports file to separate location which is placed on the test classpath
         doFirst {
           mkdir(portsFileDir)
@@ -371,7 +359,6 @@ thirdPartyAudit {
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$2',
-    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$3',
     'com.google.common.hash.Striped64',
     'com.google.common.hash.Striped64$1',
     'com.google.common.hash.Striped64$Cell',
@@ -438,10 +425,6 @@ thirdPartyAudit {
     'org.apache.hadoop.shaded.org.apache.curator.shaded.com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper',
     'org.apache.hadoop.shaded.org.apache.curator.shaded.com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper$1',
     'org.apache.hadoop.shaded.org.xbill.DNS.spi.DNSJavaNameServiceDescriptor',
-    'org.apache.hadoop.shaded.org.xerial.snappy.pure.PureJavaSnappy',
-    'org.apache.hadoop.shaded.org.xerial.snappy.pure.SnappyRawCompressor',
-    'org.apache.hadoop.shaded.org.xerial.snappy.pure.SnappyRawDecompressor',
-    'org.apache.hadoop.shaded.org.xerial.snappy.pure.UnsafeUtil',
 
     'org.apache.avro.reflect.FieldAccessUnsafe',
     'org.apache.avro.reflect.FieldAccessUnsafe$UnsafeBooleanField',
@@ -457,3 +440,7 @@ thirdPartyAudit {
     'org.apache.avro.reflect.FieldAccessUnsafe$UnsafeShortField',
   )
 }
+
+tasks.withType(JavaForkOptions) {
+  systemProperty "java.util.concurrent.ForkJoinPool.common.threadFactory", "org.opensearch.secure_sm.SecuredForkJoinWorkerThreadFactory"
+}
diff --git a/plugins/repository-hdfs/licenses/avro-1.10.2.jar.sha1 b/plugins/repository-hdfs/licenses/avro-1.10.2.jar.sha1
deleted file mode 100644
index eae1c5116ff0f..0000000000000
--- a/plugins/repository-hdfs/licenses/avro-1.10.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a65aaa91c1aeceb3dd4859dbb9765d1c2063f5a2
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/avro-1.11.2.jar.sha1 b/plugins/repository-hdfs/licenses/avro-1.11.2.jar.sha1
new file mode 100644
index 0000000000000..ce1a894e0ce6d
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/avro-1.11.2.jar.sha1
@@ -0,0 +1 @@
+97e62e8be2b37e849f1bdb5a4f08121d47cc9806
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-codec-1.13.jar.sha1 b/plugins/repository-hdfs/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-codec-1.15.jar.sha1 b/plugins/repository-hdfs/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-compress-1.21.jar.sha1 b/plugins/repository-hdfs/licenses/commons-compress-1.21.jar.sha1
deleted file mode 100644
index 81ac609a1aa26..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-compress-1.21.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4ec95b60d4e86b5c95a0e919cb172a0af98011ef
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-compress-1.24.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-compress-1.24.0.jar.sha1
new file mode 100644
index 0000000000000..23999d1bfbde4
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-compress-1.24.0.jar.sha1
@@ -0,0 +1 @@
+b4b1b5a3d9573b2970fddab236102c0a4d27d35e
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-configuration2-2.7.jar.sha1 b/plugins/repository-hdfs/licenses/commons-configuration2-2.7.jar.sha1
deleted file mode 100644
index 31e16840e2c4f..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-configuration2-2.7.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-593326399e5fb5e1f986607f06f63c1250ab36b4
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-configuration2-2.8.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-configuration2-2.8.0.jar.sha1
new file mode 100644
index 0000000000000..0f782489a571d
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-configuration2-2.8.0.jar.sha1
@@ -0,0 +1 @@
+6a76acbe14d2c01d4758a57171f3f6a150dbd462
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-io-2.11.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-io-2.11.0.jar.sha1
deleted file mode 100644
index 8adec30bade49..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-io-2.11.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-a2503f302b11ebde7ebc3df41daebe0e4eea3689
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-io-2.12.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-io-2.12.0.jar.sha1
new file mode 100644
index 0000000000000..5225b130fb817
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-io-2.12.0.jar.sha1
@@ -0,0 +1 @@
+e5e3eb2ff05b494287f51476bc715161412c525f
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-lang3-3.12.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-lang3-3.12.0.jar.sha1
deleted file mode 100644
index 9273d8c01aaba..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-lang3-3.12.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-c6842c86792ff03b9f1d1fe2aab8dc23aa6c6f0e
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-lang3-3.13.0.jar.sha1 b/plugins/repository-hdfs/licenses/commons-lang3-3.13.0.jar.sha1
new file mode 100644
index 0000000000000..d0c2f2486ee1f
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-lang3-3.13.0.jar.sha1
@@ -0,0 +1 @@
+b7263237aa89c1f99b327197c41d0669707a462e
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-lang3-NOTICE.txt b/plugins/repository-hdfs/licenses/commons-lang3-NOTICE.txt
index 8dfa22157abc3..13a3140897472 100644
--- a/plugins/repository-hdfs/licenses/commons-lang3-NOTICE.txt
+++ b/plugins/repository-hdfs/licenses/commons-lang3-NOTICE.txt
@@ -1,9 +1,5 @@
 Apache Commons Lang
-Copyright 2001-2015 The Apache Software Foundation
+Copyright 2001-2019 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
-
-This product includes software from the Spring Framework,
-under the Apache License 2.0 (see: StringUtils.containsWhitespace())
-
diff --git a/plugins/repository-hdfs/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/repository-hdfs/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index 5b8f029e58293..0000000000000
--- a/plugins/repository-hdfs/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-logging-1.2.jar.sha1 b/plugins/repository-hdfs/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/commons-logging-NOTICE.txt b/plugins/repository-hdfs/licenses/commons-logging-NOTICE.txt
index 556bd03951d4b..d3d6e140ce4f3 100644
--- a/plugins/repository-hdfs/licenses/commons-logging-NOTICE.txt
+++ b/plugins/repository-hdfs/licenses/commons-logging-NOTICE.txt
@@ -3,4 +3,3 @@ Copyright 2003-2014 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
-
diff --git a/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1 b/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1
new file mode 100644
index 0000000000000..9810309d1013a
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1
@@ -0,0 +1 @@
+b3add478d4382b78ea20b1671390a858002feb6c
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/gson-2.9.0.jar.sha1 b/plugins/repository-hdfs/licenses/gson-2.9.0.jar.sha1
deleted file mode 100644
index 8e9626b0c949b..0000000000000
--- a/plugins/repository-hdfs/licenses/gson-2.9.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8a1167e089096758b49f9b34066ef98b2f4b37aa
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/guava-30.1.1-jre.jar.sha1 b/plugins/repository-hdfs/licenses/guava-30.1.1-jre.jar.sha1
deleted file mode 100644
index 39e641fc7834f..0000000000000
--- a/plugins/repository-hdfs/licenses/guava-30.1.1-jre.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-87e0fd1df874ea3cbe577702fe6f17068b790fd8
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/guava-32.1.1-jre.jar.sha1 b/plugins/repository-hdfs/licenses/guava-32.1.1-jre.jar.sha1
new file mode 100644
index 0000000000000..0d791b5d3f55b
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/guava-32.1.1-jre.jar.sha1
@@ -0,0 +1 @@
+ad575652d84153075dd41ec6177ccb15251262b2
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.1.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.1.jar.sha1
deleted file mode 100644
index dc2f20e310d30..0000000000000
--- a/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4b9c9cdd9967495838fb521001699c4c9dddf183
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.6.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.6.jar.sha1
new file mode 100644
index 0000000000000..d99793bc56522
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/hadoop-client-api-3.3.6.jar.sha1
@@ -0,0 +1 @@
+12ac6f103a0ff29fce17a078c7c64d25320b6165
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.1.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.1.jar.sha1
deleted file mode 100644
index feb37ecc90255..0000000000000
--- a/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f3a55d882328ee87a1054f99d62ba987fa9029a4
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.6.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.6.jar.sha1
new file mode 100644
index 0000000000000..ea22d763b7bfa
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/hadoop-client-runtime-3.3.6.jar.sha1
@@ -0,0 +1 @@
+81065531e63fccbe85fb04a3274709593fb00d3c
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.1.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.1.jar.sha1
deleted file mode 100644
index 66c98cf7ec291..0000000000000
--- a/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-5da7f270cb6564e099e0d2d424285a24fca62bd2
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.6.jar.sha1 b/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.6.jar.sha1
new file mode 100644
index 0000000000000..fe60968056eb7
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/hadoop-hdfs-3.3.6.jar.sha1
@@ -0,0 +1 @@
+ba40aca60f39599d5b1f1d32b35295bfde1f3c8b
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/htrace-core4-4.1.0-incubating.jar.sha1 b/plugins/repository-hdfs/licenses/htrace-core4-4.1.0-incubating.jar.sha1
deleted file mode 100644
index 806c624c02cf0..0000000000000
--- a/plugins/repository-hdfs/licenses/htrace-core4-4.1.0-incubating.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-12b3e2adda95e8c41d9d45d33db075137871d2e2
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/htrace-core4-4.2.0-incubating.jar.sha1 b/plugins/repository-hdfs/licenses/htrace-core4-4.2.0-incubating.jar.sha1
new file mode 100644
index 0000000000000..e2eafb09dba00
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/htrace-core4-4.2.0-incubating.jar.sha1
@@ -0,0 +1 @@
+94b3f1966922bc45d0f8a86a2aa867a4b0df288b
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/jackson-databind-2.13.2.jar.sha1 b/plugins/repository-hdfs/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/plugins/repository-hdfs/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/json-smart-2.4.11.jar.sha1 b/plugins/repository-hdfs/licenses/json-smart-2.4.11.jar.sha1
new file mode 100644
index 0000000000000..04627ab2baace
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/json-smart-2.4.11.jar.sha1
@@ -0,0 +1 @@
+cc5888f14a5768f254b97bafe8b9fd29b31e872e
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/json-smart-2.4.7.jar.sha1 b/plugins/repository-hdfs/licenses/json-smart-2.4.7.jar.sha1
deleted file mode 100644
index 16f9a4431485a..0000000000000
--- a/plugins/repository-hdfs/licenses/json-smart-2.4.7.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8d7f4c1530c07c54930935f3da85f48b83b3c109
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.17.1.jar.sha1 b/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.17.1.jar.sha1
deleted file mode 100644
index 894ed8d886c3f..0000000000000
--- a/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-84692d456bcce689355d33d68167875e486954dd
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.20.0.jar.sha1 b/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..800a4aa87ba0e
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/log4j-slf4j-impl-2.20.0.jar.sha1
@@ -0,0 +1 @@
+7ab4f082fd162f60afcaf2b8744a3d959feab3e8
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/netty-all-4.1.73.Final.jar.sha1 b/plugins/repository-hdfs/licenses/netty-all-4.1.73.Final.jar.sha1
deleted file mode 100644
index 52d6f22e73013..0000000000000
--- a/plugins/repository-hdfs/licenses/netty-all-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-75c5a0ddb28adcc9e4991c75678d4a85dfe4a0b3
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/netty-all-4.1.99.Final.jar.sha1 b/plugins/repository-hdfs/licenses/netty-all-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..0756635018837
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/netty-all-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+a45aa70bc50d0500da5cdcd595cc838d87ada987
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/protobuf-java-3.19.3.jar.sha1 b/plugins/repository-hdfs/licenses/protobuf-java-3.19.3.jar.sha1
deleted file mode 100644
index 655ecd1f1c1c9..0000000000000
--- a/plugins/repository-hdfs/licenses/protobuf-java-3.19.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4b57f1b1b9e281231c3fcfc039ce3021e29ff570
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/protobuf-java-LICENSE.txt b/plugins/repository-hdfs/licenses/protobuf-java-LICENSE.txt
deleted file mode 100644
index 49e7019ac5a1b..0000000000000
--- a/plugins/repository-hdfs/licenses/protobuf-java-LICENSE.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Copyright (c) <YEAR>, <OWNER>
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
-
-1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
-
-2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/plugins/repository-hdfs/licenses/protobuf-java-NOTICE.txt b/plugins/repository-hdfs/licenses/protobuf-java-NOTICE.txt
deleted file mode 100644
index 139597f9cb07c..0000000000000
--- a/plugins/repository-hdfs/licenses/protobuf-java-NOTICE.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-
-
diff --git a/plugins/repository-hdfs/licenses/re2j-1.1.jar.sha1 b/plugins/repository-hdfs/licenses/re2j-1.1.jar.sha1
deleted file mode 100644
index d8a100dafd8c4..0000000000000
--- a/plugins/repository-hdfs/licenses/re2j-1.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d716952ab58aa4369ea15126505a36544d50a333
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/re2j-1.6.jar.sha1 b/plugins/repository-hdfs/licenses/re2j-1.6.jar.sha1
new file mode 100644
index 0000000000000..854bd3a225b92
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/re2j-1.6.jar.sha1
@@ -0,0 +1 @@
+a13e879fd7971738d06020fefeb108cc14e14169
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/slf4j-api-1.6.2.jar.sha1 b/plugins/repository-hdfs/licenses/slf4j-api-1.6.2.jar.sha1
deleted file mode 100644
index a2f93ea55802b..0000000000000
--- a/plugins/repository-hdfs/licenses/slf4j-api-1.6.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-8619e95939167fb37245b5670135e4feb0ec7d50
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/repository-hdfs/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/woodstox-core-6.2.8.jar.sha1 b/plugins/repository-hdfs/licenses/woodstox-core-6.2.8.jar.sha1
deleted file mode 100644
index ae65cdebf26de..0000000000000
--- a/plugins/repository-hdfs/licenses/woodstox-core-6.2.8.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-670748292899c53b1963730d9eb7f8ab71314e90
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/woodstox-core-6.4.0.jar.sha1 b/plugins/repository-hdfs/licenses/woodstox-core-6.4.0.jar.sha1
new file mode 100644
index 0000000000000..cac5f37205956
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/woodstox-core-6.4.0.jar.sha1
@@ -0,0 +1 @@
+c47579857bbf12c85499f431d4ecf27d77976b7c
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/zookeeper-3.7.0.jar.sha1 b/plugins/repository-hdfs/licenses/zookeeper-3.7.0.jar.sha1
deleted file mode 100644
index 88a6106a68710..0000000000000
--- a/plugins/repository-hdfs/licenses/zookeeper-3.7.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1360048c7ca057df627b7267ff7360870e987ab0
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/zookeeper-LICENSE.txt b/plugins/repository-hdfs/licenses/zookeeper-LICENSE.txt
deleted file mode 100644
index 7a4a3ea2424c0..0000000000000
--- a/plugins/repository-hdfs/licenses/zookeeper-LICENSE.txt
+++ /dev/null
@@ -1,202 +0,0 @@
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/zookeeper-NOTICE.txt b/plugins/repository-hdfs/licenses/zookeeper-NOTICE.txt
deleted file mode 100644
index b853f3e85f32f..0000000000000
--- a/plugins/repository-hdfs/licenses/zookeeper-NOTICE.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-Apache ZooKeeper
-Copyright 2009-2021 The Apache Software Foundation
-
-This product includes software developed at
-The Apache Software Foundation (http://www.apache.org/).
-
-This product includes software components originally
-developed for Airlift (https://github.com/airlift/airlift),
-licensed under the Apache 2.0 license. The licensing terms
-for Airlift code can be found at:
-https://github.com/airlift/airlift/blob/master/LICENSE
\ No newline at end of file
diff --git a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsBlobContainer.java b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsBlobContainer.java
index dcbd52d311230..669190f4e2490 100644
--- a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsBlobContainer.java
+++ b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsBlobContainer.java
@@ -32,6 +32,7 @@
 package org.opensearch.repositories.hdfs;
 
 import org.apache.hadoop.fs.CreateFlag;
+import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileContext;
 import org.apache.hadoop.fs.FileStatus;
@@ -46,6 +47,7 @@
 import org.opensearch.common.blobstore.fs.FsBlobContainer;
 import org.opensearch.common.blobstore.support.AbstractBlobContainer;
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
+import org.opensearch.common.io.Streams;
 import org.opensearch.repositories.hdfs.HdfsBlobStore.Operation;
 
 import java.io.FileNotFoundException;
@@ -125,8 +127,23 @@ public InputStream readBlob(String blobName) throws IOException {
     }
 
     @Override
-    public InputStream readBlob(String blobName, long position, long length) {
-        throw new UnsupportedOperationException();
+    public InputStream readBlob(String blobName, long position, long length) throws IOException {
+        return store.execute(fileContext -> {
+            final FSDataInputStream stream;
+            try {
+                stream = fileContext.open(new Path(path, blobName), bufferSize);
+            } catch (FileNotFoundException fnfe) {
+                throw new NoSuchFileException("[" + blobName + "] blob not found");
+            }
+            // Seek to the desired start position, closing the stream if any error occurs
+            try {
+                stream.seek(position);
+            } catch (Exception e) {
+                stream.close();
+                throw e;
+            }
+            return Streams.limitStream(new HDFSPrivilegedInputSteam(stream, securityContext), length);
+        });
     }
 
     @Override
diff --git a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsPlugin.java b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsPlugin.java
index 4b715a509a195..119d060374be2 100644
--- a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsPlugin.java
+++ b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsPlugin.java
@@ -31,27 +31,27 @@
 
 package org.opensearch.repositories.hdfs;
 
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
-import java.util.Collections;
-import java.util.Map;
-
 import org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolPB;
 import org.apache.hadoop.security.KerberosInfo;
 import org.apache.hadoop.security.SecurityUtil;
 import org.opensearch.SpecialPermission;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.RepositoryPlugin;
 import org.opensearch.repositories.Repository;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Collections;
+import java.util.Map;
+
 public final class HdfsPlugin extends Plugin implements RepositoryPlugin {
 
     // initialize some problematic classes with elevated privileges
diff --git a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsRepository.java b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsRepository.java
index 3be6fba5322db..f0ffec5713c1d 100644
--- a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsRepository.java
+++ b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsRepository.java
@@ -45,12 +45,12 @@
 import org.opensearch.SpecialPermission;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
@@ -83,7 +83,7 @@ public HdfsRepository(
         final ClusterService clusterService,
         final RecoverySettings recoverySettings
     ) {
-        super(metadata, metadata.settings().getAsBoolean("compress", false), namedXContentRegistry, clusterService, recoverySettings);
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings);
 
         this.environment = environment;
         this.chunkSize = metadata.settings().getAsBytesSize("chunk_size", null);
diff --git a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsSecurityContext.java b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsSecurityContext.java
index 9078e2b76cc6d..2e62ae48d1a06 100644
--- a/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsSecurityContext.java
+++ b/plugins/repository-hdfs/src/main/java/org/opensearch/repositories/hdfs/HdfsSecurityContext.java
@@ -31,6 +31,14 @@
 
 package org.opensearch.repositories.hdfs;
 
+import org.apache.hadoop.security.UserGroupInformation;
+import org.opensearch.SpecialPermission;
+import org.opensearch.env.Environment;
+
+import javax.security.auth.AuthPermission;
+import javax.security.auth.PrivateCredentialPermission;
+import javax.security.auth.kerberos.ServicePermission;
+
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.lang.reflect.ReflectPermission;
@@ -42,13 +50,6 @@
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.Arrays;
-import javax.security.auth.AuthPermission;
-import javax.security.auth.PrivateCredentialPermission;
-import javax.security.auth.kerberos.ServicePermission;
-
-import org.apache.hadoop.security.UserGroupInformation;
-import org.opensearch.SpecialPermission;
-import org.opensearch.env.Environment;
 
 /**
  * Oversees all the security specific logic for the HDFS Repository plugin.
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HaHdfsFailoverTestSuiteIT.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HaHdfsFailoverTestSuiteIT.java
index e12b24f27dcdc..d0b63f17e3887 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HaHdfsFailoverTestSuiteIT.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HaHdfsFailoverTestSuiteIT.java
@@ -75,9 +75,9 @@ public void testHAFailoverWithRepository() throws Exception {
         String nn2Port = "10002";
         if (ports.length() > 0) {
             final Path path = PathUtils.get(ports);
-            final List<String> lines = AccessController.doPrivileged(
-                (PrivilegedExceptionAction<List<String>>) () -> { return Files.readAllLines(path); }
-            );
+            final List<String> lines = AccessController.doPrivileged((PrivilegedExceptionAction<List<String>>) () -> {
+                return Files.readAllLines(path);
+            });
             nn1Port = lines.get(0);
             nn2Port = lines.get(1);
         }
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreContainerTests.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreContainerTests.java
index 66677b0327191..3a6eb0e205ccb 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreContainerTests.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreContainerTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.repositories.hdfs;
 
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.AbstractFileSystem;
 import org.apache.hadoop.fs.FileContext;
@@ -41,7 +42,7 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.test.OpenSearchTestCase;
 
 import javax.security.auth.Subject;
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreRepositoryTests.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreRepositoryTests.java
index 9196a8f2b0558..6ff18b20036a8 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreRepositoryTests.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsBlobStoreRepositoryTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.repositories.hdfs;
 
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.blobstore.OpenSearchBlobStoreRepositoryIntegTestCase;
@@ -65,4 +66,8 @@ protected Settings repositorySettings() {
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singletonList(HdfsPlugin.class);
     }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9513")
+    @Override
+    public void testReadRange() {}
 }
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsClientThreadLeakFilter.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsClientThreadLeakFilter.java
index b9b0e9e87dd0c..2758bd020e979 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsClientThreadLeakFilter.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsClientThreadLeakFilter.java
@@ -43,6 +43,9 @@
  * to ignore the offending thread until a version of Hadoop is released that addresses the incorrect
  * interrupt handling.
  *
+ * In Hadoop 3.3.6, the org.apache.hadoop.fs.statistics.impl.EvaluatingStatisticsMap uses ForkJoinPool
+ * to perform statistics calculation, leaving dangling workers.
+ *
  * @see <a href="https://issues.apache.org/jira/browse/HADOOP-12829">https://issues.apache.org/jira/browse/HADOOP-12829</a>
  * @see "org.apache.hadoop.fs.FileSystem.Statistics.StatisticsDataReferenceCleaner"
  * @see "org.apache.hadoop.fs.FileSystem.Statistics"
@@ -53,6 +56,6 @@ public final class HdfsClientThreadLeakFilter implements ThreadFilter {
 
     @Override
     public boolean reject(Thread t) {
-        return t.getName().equals(OFFENDING_THREAD_NAME);
+        return t.getName().equals(OFFENDING_THREAD_NAME) || t.getName().startsWith("ForkJoinPool.commonPool-");
     }
 }
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsRepositoryTests.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsRepositoryTests.java
index 4e12de7cce212..ab10691240649 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsRepositoryTests.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsRepositoryTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.repositories.hdfs;
 
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
-import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryResponse;
 
+import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.SecureSettings;
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsTests.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsTests.java
index 46d97f41b604f..ce456f26af3a4 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsTests.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/HdfsTests.java
@@ -32,11 +32,10 @@
 package org.opensearch.repositories.hdfs;
 
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
-
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.common.settings.Settings;
@@ -63,7 +62,6 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testSimpleWorkflow() {
-        assumeFalse("https://github.com/elastic/elasticsearch/issues/31498", JavaVersion.current().equals(JavaVersion.parse("11")));
         Client client = client();
 
         AcknowledgedResponse putRepositoryResponse = client.admin()
diff --git a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/TestingFs.java b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/TestingFs.java
index 8fca4f9afd771..faa8d1d891c1f 100644
--- a/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/TestingFs.java
+++ b/plugins/repository-hdfs/src/test/java/org/opensearch/repositories/hdfs/TestingFs.java
@@ -43,11 +43,11 @@
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.spi.FileSystemProvider;
-import java.nio.file.Files;
-import java.nio.file.NoSuchFileException;
 
 /**
  * Extends LFS to improve some operations to keep the security permissions at
diff --git a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/10_basic.yml b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/10_basic.yml
index bc419d75ba773..eedcaf099ccef 100644
--- a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/10_basic.yml
+++ b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/10_basic.yml
@@ -9,13 +9,13 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: repository-hdfs } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: repository-hdfs } }
 ---
 #
 # Check that we can't use file:// repositories or anything like that
diff --git a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot.yml b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot.yml
index 20019686d3db1..7e76024dd2368 100644
--- a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot.yml
+++ b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot.yml
@@ -36,7 +36,7 @@
   - match: { snapshot.shards.failed : 0 }
 
   # Remove our snapshot
-  - do: 
+  - do:
       snapshot.delete:
         repository: test_snapshot_repository
         snapshot: test_snapshot
@@ -45,4 +45,3 @@
   - do:
      snapshot.delete_repository:
        repository: test_snapshot_repository
-
diff --git a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot_get.yml b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot_get.yml
index f38f4783b195b..3e61ef62f2a7d 100644
--- a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot_get.yml
+++ b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/hdfs_repository/30_snapshot_get.yml
@@ -59,7 +59,7 @@
   - match: { snapshots.0.snapshot : test_snapshot_get }
 
   # Remove our snapshot
-  - do: 
+  - do:
       snapshot.delete:
         repository: test_snapshot_get_repository
         snapshot: test_snapshot_get
diff --git a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/10_basic.yml b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/10_basic.yml
index bc419d75ba773..eedcaf099ccef 100644
--- a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/10_basic.yml
+++ b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/10_basic.yml
@@ -9,13 +9,13 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: repository-hdfs } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: repository-hdfs } }
 ---
 #
 # Check that we can't use file:// repositories or anything like that
diff --git a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/30_snapshot.yml b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/30_snapshot.yml
index 44f29fe0341a6..821110dc52bed 100644
--- a/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/30_snapshot.yml
+++ b/plugins/repository-hdfs/src/test/resources/rest-api-spec/test/secure_hdfs_repository/30_snapshot.yml
@@ -47,4 +47,3 @@
   - do:
      snapshot.delete_repository:
        repository: test_snapshot_repository
-
diff --git a/plugins/repository-s3/README.md b/plugins/repository-s3/README.md
new file mode 100644
index 0000000000000..03007e03b633e
--- /dev/null
+++ b/plugins/repository-s3/README.md
@@ -0,0 +1,25 @@
+# repository-s3
+
+The repository-s3 plugin enables the use of S3 as a place to store snapshots.
+
+## Testing
+
+### Unit Tests
+
+```
+./gradlew :plugins:repository-s3:test
+```
+
+### Integration Tests
+
+Integration tests require several environment variables.
+
+-  `amazon_s3_bucket`: Name of the S3 bucket to use.
+-  `amazon_s3_access_key`: The access key ID (`AWS_ACCESS_KEY_ID`) with r/w access to the S3 bucket.
+-  `amazon_s3_secret_key`: The secret access key (`AWS_SECRET_ACCESS_KEY`).
+-  `amazon_s3_base_path`: A relative path inside the S3 bucket, e.g. `opensearch`.
+-  `AWS_REGION`: The region in which the S3 bucket was created. While S3 buckets are global, credentials must scoped to a specific region and cross-region access is not allowed. (TODO: rename this to `amazon_s3_region` in https://github.com/opensearch-project/opensearch-build/issues/3615 and https://github.com/opensearch-project/OpenSearch/pull/7974.)
+
+```
+AWS_REGION=us-west-2 amazon_s3_access_key=$AWS_ACCESS_KEY_ID amazon_s3_secret_key=$AWS_SECRET_ACCESS_KEY amazon_s3_base_path=path amazon_s3_bucket=dblock-opensearch ./gradlew :plugins:repository-s3:s3ThirdPartyTest
+```
diff --git a/plugins/repository-s3/build.gradle b/plugins/repository-s3/build.gradle
index c5939958c816a..44fd45b265e82 100644
--- a/plugins/repository-s3/build.gradle
+++ b/plugins/repository-s3/build.gradle
@@ -31,6 +31,7 @@
 import org.opensearch.gradle.MavenFilteringHack
 import org.opensearch.gradle.info.BuildParams
 import org.opensearch.gradle.test.RestIntegTestTask
+import org.opensearch.gradle.test.TestTask
 import org.opensearch.gradle.test.rest.YamlRestTestPlugin
 import org.opensearch.gradle.test.InternalClusterTestPlugin
 
@@ -44,24 +45,55 @@ opensearchplugin {
   classname 'org.opensearch.repositories.s3.S3RepositoryPlugin'
 }
 
-versions << [
-  'aws': '1.11.749'
-]
-
 dependencies {
-  api "com.amazonaws:aws-java-sdk-s3:${versions.aws}"
-  api "com.amazonaws:aws-java-sdk-core:${versions.aws}"
-  api "com.amazonaws:jmespath-java:${versions.aws}"
+  // aws sdk v2 stack
+  api "software.amazon.awssdk:sdk-core:${versions.aws}"
+  api "software.amazon.awssdk:annotations:${versions.aws}"
+  api "software.amazon.awssdk:aws-core:${versions.aws}"
+  api "software.amazon.awssdk:auth:${versions.aws}"
+  api "software.amazon.awssdk:endpoints-spi:${versions.aws}"
+  api "software.amazon.awssdk:http-client-spi:${versions.aws}"
+  api "software.amazon.awssdk:apache-client:${versions.aws}"
+  api "software.amazon.awssdk:metrics-spi:${versions.aws}"
+  api "software.amazon.awssdk:profiles:${versions.aws}"
+  api "software.amazon.awssdk:regions:${versions.aws}"
+  api "software.amazon.awssdk:utils:${versions.aws}"
+  api "software.amazon.awssdk:aws-json-protocol:${versions.aws}"
+  api "software.amazon.awssdk:protocol-core:${versions.aws}"
+  api "software.amazon.awssdk:json-utils:${versions.aws}"
+  api "software.amazon.awssdk:third-party-jackson-core:${versions.aws}"
+  api "software.amazon.awssdk:s3:${versions.aws}"
+  api "software.amazon.awssdk:signer:${versions.aws}"
+  api "software.amazon.awssdk:aws-xml-protocol:${versions.aws}"
+  api "software.amazon.awssdk:aws-json-protocol:${versions.aws}"
+  api "software.amazon.awssdk:aws-query-protocol:${versions.aws}"
+  api "software.amazon.awssdk:sts:${versions.aws}"
+  api "software.amazon.awssdk:netty-nio-client:${versions.aws}"
+
+  api "org.reactivestreams:reactive-streams:${versions.reactivestreams}"
   api "org.apache.httpcomponents:httpclient:${versions.httpclient}"
   api "org.apache.httpcomponents:httpcore:${versions.httpcore}"
   api "commons-logging:commons-logging:${versions.commonslogging}"
   api "org.apache.logging.log4j:log4j-1.2-api:${versions.log4j}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
   api "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
-  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
   api "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
   api "com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:${versions.jackson}"
   api "joda-time:joda-time:${versions.joda}"
+  api "org.slf4j:slf4j-api:${versions.slf4j}"
+
+  // network stack
+  api "io.netty:netty-buffer:${versions.netty}"
+  api "io.netty:netty-codec:${versions.netty}"
+  api "io.netty:netty-codec-http:${versions.netty}"
+  api "io.netty:netty-codec-http2:${versions.netty}"
+  api "io.netty:netty-common:${versions.netty}"
+  api "io.netty:netty-handler:${versions.netty}"
+  api "io.netty:netty-resolver:${versions.netty}"
+  api "io.netty:netty-transport:${versions.netty}"
+  api "io.netty:netty-transport-native-unix-common:${versions.netty}"
+  api "io.netty:netty-transport-classes-epoll:${versions.netty}"
 
   // HACK: javax.xml.bind was removed from default modules in java 9, so we pull the api in here,
   // and allowlist this hack in JarHell
@@ -77,10 +109,9 @@ restResources {
 }
 
 tasks.named("dependencyLicenses").configure {
-  mapping from: /aws-java-sdk-.*/, to: 'aws-java-sdk'
-  mapping from: /jmespath-java.*/, to: 'aws-java-sdk'
   mapping from: /jackson-.*/, to: 'jackson'
   mapping from: /jaxb-.*/, to: 'jaxb'
+  mapping from: /netty-.*/, to: 'netty'
 }
 
 bundlePlugin {
@@ -89,7 +120,7 @@ bundlePlugin {
   }
 }
 
-task testRepositoryCreds(type: Test) {
+task testRepositoryCreds(type: TestTask) {
   include '**/RepositoryCredentialsTests.class'
   systemProperty 'opensearch.allow_insecure_settings', 'true'
 }
@@ -117,12 +148,14 @@ String s3PermanentAccessKey = System.getenv("amazon_s3_access_key")
 String s3PermanentSecretKey = System.getenv("amazon_s3_secret_key")
 String s3PermanentBucket = System.getenv("amazon_s3_bucket")
 String s3PermanentBasePath = System.getenv("amazon_s3_base_path")
+String s3PermanentRegion = System.getenv("amazon_s3_region")
 
 String s3TemporaryAccessKey = System.getenv("amazon_s3_access_key_temporary")
 String s3TemporarySecretKey = System.getenv("amazon_s3_secret_key_temporary")
 String s3TemporarySessionToken = System.getenv("amazon_s3_session_token_temporary")
 String s3TemporaryBucket = System.getenv("amazon_s3_bucket_temporary")
 String s3TemporaryBasePath = System.getenv("amazon_s3_base_path_temporary")
+String s3TemporaryRegion = System.getenv("amazon_s3_region_temporary")
 
 String s3EC2Bucket = System.getenv("amazon_s3_bucket_ec2")
 String s3EC2BasePath = System.getenv("amazon_s3_base_path_ec2")
@@ -130,55 +163,76 @@ String s3EC2BasePath = System.getenv("amazon_s3_base_path_ec2")
 String s3ECSBucket = System.getenv("amazon_s3_bucket_ecs")
 String s3ECSBasePath = System.getenv("amazon_s3_base_path_ecs")
 
+String s3EKSBucket = System.getenv("amazon_s3_bucket_eks")
+String s3EKSBasePath = System.getenv("amazon_s3_base_path_eks")
+
 boolean s3DisableChunkedEncoding = (new Random(Long.parseUnsignedLong(BuildParams.testSeed.tokenize(':').get(0), 16))).nextBoolean()
 
+// TODO: remove after https://github.com/opensearch-project/opensearch-build/issues/3615
+if (s3PermanentBucket && !s3PermanentRegion) {
+  s3PermanentRegion = "us-west-2"
+}
+
+if (s3TemporaryBucket && !s3TemporaryRegion) {
+  s3TemporaryRegion = "us-west-2"
+}
+// ----
+
 // If all these variables are missing then we are testing against the internal fixture instead, which has the following
 // credentials hard-coded in.
 
-if (!s3PermanentAccessKey && !s3PermanentSecretKey && !s3PermanentBucket && !s3PermanentBasePath) {
+if (!s3PermanentAccessKey && !s3PermanentSecretKey && !s3PermanentBucket && !s3PermanentBasePath && !s3PermanentRegion) {
   s3PermanentAccessKey = 'access_key'
   s3PermanentSecretKey = 'secret_key'
   s3PermanentBucket = 'bucket'
   s3PermanentBasePath = 'base_path'
+  s3PermanentRegion = 'region'
 
   apply plugin: 'opensearch.test.fixtures'
   useFixture = true
 
-} else if (!s3PermanentAccessKey || !s3PermanentSecretKey || !s3PermanentBucket || !s3PermanentBasePath) {
+} else if (!s3PermanentAccessKey || !s3PermanentSecretKey || !s3PermanentBucket || !s3PermanentBasePath || !s3PermanentRegion) {
   throw new IllegalArgumentException("not all options specified to run against external S3 service as permanent credentials are present")
 }
 
-if (!s3TemporaryAccessKey && !s3TemporarySecretKey && !s3TemporaryBucket && !s3TemporaryBasePath && !s3TemporarySessionToken) {
+if (!s3TemporaryAccessKey && !s3TemporarySecretKey && !s3TemporaryBucket && !s3TemporaryBasePath && !s3TemporarySessionToken && !s3TemporaryRegion) {
   s3TemporaryAccessKey = 'session_token_access_key'
   s3TemporarySecretKey = 'session_token_secret_key'
   s3TemporaryBucket = 'session_token_bucket'
   s3TemporaryBasePath = 'session_token_base_path'
   s3TemporarySessionToken = 'session_token'
+  s3TemporaryRegion = 'session_token_region'
 
 } else if (!s3TemporaryAccessKey || !s3TemporarySecretKey || !s3TemporaryBucket || !s3TemporaryBasePath || !s3TemporarySessionToken) {
   throw new IllegalArgumentException("not all options specified to run against external S3 service as temporary credentials are present")
 }
 
-if (!s3EC2Bucket && !s3EC2BasePath && !s3ECSBucket && !s3ECSBasePath) {
+if (!s3EC2Bucket && !s3EC2BasePath && !s3ECSBucket && !s3ECSBasePath && !s3EKSBucket && !s3EKSBasePath) {
   s3EC2Bucket = 'ec2_bucket'
   s3EC2BasePath = 'ec2_base_path'
   s3ECSBucket = 'ecs_bucket'
   s3ECSBasePath = 'ecs_base_path'
-} else if (!s3EC2Bucket || !s3EC2BasePath || !s3ECSBucket || !s3ECSBasePath) {
-  throw new IllegalArgumentException("not all options specified to run EC2/ECS tests are present")
+  s3EKSBucket = 'eks_bucket'
+  s3EKSBasePath = 'eks_base_path'
+} else if (!s3EC2Bucket || !s3EC2BasePath || !s3ECSBucket || !s3ECSBasePath || !s3EKSBucket || !s3EKSBasePath) {
+  throw new IllegalArgumentException("not all options specified to run EC2/ECS/EKS tests are present")
 }
 
 processYamlRestTestResources {
   Map<String, Object> expansions = [
     'permanent_bucket': s3PermanentBucket,
-    'permanent_base_path': s3PermanentBasePath + "_integration_tests",
+    'permanent_base_path': s3PermanentBasePath + "_integration_tests_" + BuildParams.testSeed,
+    'permanent_region': s3PermanentRegion,
     'temporary_bucket': s3TemporaryBucket,
-    'temporary_base_path': s3TemporaryBasePath + "_integration_tests",
+    'temporary_base_path': s3TemporaryBasePath + "_integration_tests_" + BuildParams.testSeed,
+    'temporary_region': s3TemporaryRegion,
     'ec2_bucket': s3EC2Bucket,
     'ec2_base_path': s3EC2BasePath,
     'ecs_bucket': s3ECSBucket,
     'ecs_base_path': s3ECSBasePath,
-    'disable_chunked_encoding': s3DisableChunkedEncoding,
+    'eks_bucket': s3EKSBucket,
+    'eks_base_path': s3EKSBasePath,
+    'disable_chunked_encoding': s3DisableChunkedEncoding
   ]
   inputs.properties(expansions)
   MavenFilteringHack.filter(it, expansions)
@@ -190,14 +244,15 @@ internalClusterTest {
 }
 
 yamlRestTest {
-    systemProperty 'tests.rest.blacklist', (
+    systemProperty 'tests.rest.denylist', (
       useFixture ?
         ['repository_s3/50_repository_ecs_credentials/*']
         :
         [
           'repository_s3/30_repository_temporary_credentials/*',
           'repository_s3/40_repository_ec2_credentials/*',
-          'repository_s3/50_repository_ecs_credentials/*'
+          'repository_s3/50_repository_ecs_credentials/*',
+          'repository_s3/60_repository_eks_credentials/*'
         ]
     ).join(",")
 }
@@ -214,6 +269,7 @@ testClusters.yamlRestTest {
     testFixtures.useFixture(':test:fixtures:s3-fixture', 's3-fixture')
     testFixtures.useFixture(':test:fixtures:s3-fixture', 's3-fixture-with-session-token')
     testFixtures.useFixture(':test:fixtures:s3-fixture', 's3-fixture-with-ec2')
+    testFixtures.useFixture(':test:fixtures:s3-fixture', 's3-fixture-with-eks')
 
     normalization {
       runtimeClasspath {
@@ -222,12 +278,21 @@ testClusters.yamlRestTest {
       }
     }
 
+    keystore 's3.client.integration_test_eks.role_arn', "arn:aws:iam::000000000000:role/test"
+    keystore 's3.client.integration_test_eks.role_session_name', "s3-test"
+    keystore 's3.client.integration_test_eks.access_key', "access_key"
+    keystore 's3.client.integration_test_eks.secret_key', "secret_key"
+
     setting 's3.client.integration_test_permanent.endpoint', { "${-> fixtureAddress('s3-fixture', 's3-fixture', '80')}" }, IGNORE_VALUE
     setting 's3.client.integration_test_temporary.endpoint', { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-session-token', '80')}" }, IGNORE_VALUE
     setting 's3.client.integration_test_ec2.endpoint', { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-ec2', '80')}" }, IGNORE_VALUE
+    setting 's3.client.integration_test_eks.endpoint', { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-eks', '80')}" }, IGNORE_VALUE
+    setting 's3.client.integration_test_eks.region', { "us-east-2" }, IGNORE_VALUE
 
     // to redirect InstanceProfileCredentialsProvider to custom auth point
-    systemProperty "com.amazonaws.sdk.ec2MetadataServiceEndpointOverride", { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-ec2', '80')}" }, IGNORE_VALUE
+    systemProperty "aws.ec2MetadataServiceEndpointOverride", { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-ec2', '80')}" }, IGNORE_VALUE
+    // to redirect AWSSecurityTokenServiceClient to custom auth point
+    systemProperty "aws.stsEndpointOverride", { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-eks', '80')}/eks_credentials_endpoint" }, IGNORE_VALUE
   } else {
     println "Using an external service to test the repository-s3 plugin"
   }
@@ -246,10 +311,11 @@ if (useFixture) {
     setClasspath(yamlRestTestSourceSet.getRuntimeClasspath())
 
     // Minio only supports a single access key, see https://github.com/minio/minio/pull/5968
-    systemProperty 'tests.rest.blacklist', [
+    systemProperty 'tests.rest.denylist', [
       'repository_s3/30_repository_temporary_credentials/*',
       'repository_s3/40_repository_ec2_credentials/*',
-      'repository_s3/50_repository_ecs_credentials/*'
+      'repository_s3/50_repository_ecs_credentials/*',
+      'repository_s3/60_repository_eks_credentials/*'
     ].join(",")
   }
   check.dependsOn(yamlRestTestMinio)
@@ -272,11 +338,12 @@ if (useFixture) {
     SourceSet yamlRestTestSourceSet = sourceSets.getByName(YamlRestTestPlugin.SOURCE_SET_NAME)
     setTestClassesDirs(yamlRestTestSourceSet.getOutput().getClassesDirs())
     setClasspath(yamlRestTestSourceSet.getRuntimeClasspath())
-    systemProperty 'tests.rest.blacklist', [
+    systemProperty 'tests.rest.denylist', [
       'repository_s3/10_basic/*',
       'repository_s3/20_repository_permanent_credentials/*',
       'repository_s3/30_repository_temporary_credentials/*',
-      'repository_s3/40_repository_ec2_credentials/*'
+      'repository_s3/40_repository_ec2_credentials/*',
+      'repository_s3/60_repository_eks_credentials/*'
     ].join(",")
   }
   check.dependsOn(yamlRestTestECS)
@@ -288,6 +355,41 @@ if (useFixture) {
   }
 }
 
+// EKS
+if (useFixture) {
+  testFixtures.useFixture(':test:fixtures:s3-fixture', 's3-fixture-with-eks')
+  task yamlRestTestEKS(type: RestIntegTestTask.class) {
+    description = "Runs tests using the EKS repository."
+    dependsOn('bundlePlugin')
+    SourceSetContainer sourceSets = project.getExtensions().getByType(SourceSetContainer.class);
+    SourceSet yamlRestTestSourceSet = sourceSets.getByName(YamlRestTestPlugin.SOURCE_SET_NAME)
+    setTestClassesDirs(yamlRestTestSourceSet.getOutput().getClassesDirs())
+    setClasspath(yamlRestTestSourceSet.getRuntimeClasspath())
+    systemProperty 'tests.rest.denylist', [
+      'repository_s3/10_basic/*',
+      'repository_s3/20_repository_permanent_credentials/*',
+      'repository_s3/30_repository_temporary_credentials/*',
+      'repository_s3/40_repository_ec2_credentials/*',
+      'repository_s3/50_repository_ecs_credentials/*'
+    ].join(",")
+  }
+  check.dependsOn(yamlRestTestEKS)
+
+  testClusters.yamlRestTestEKS {
+    keystore 's3.client.integration_test_eks.role_arn', "arn:aws:iam::000000000000:role/test"
+    keystore 's3.client.integration_test_eks.role_session_name', "s3-test"
+    keystore 's3.client.integration_test_eks.access_key', "access_key"
+    keystore 's3.client.integration_test_eks.secret_key', "secret_key"
+
+    setting 's3.client.integration_test_eks.endpoint', { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-eks', '80')}" }, IGNORE_VALUE
+    setting 's3.client.integration_test_eks.region', { "us-east-2" }, IGNORE_VALUE
+    plugin tasks.bundlePlugin.archiveFile
+
+    // to redirect AWSSecurityTokenServiceClient to custom auth point
+    systemProperty "aws.stsEndpointOverride", { "${-> fixtureAddress('s3-fixture', 's3-fixture-with-eks', '80')}/eks_credentials_endpoint" }, IGNORE_VALUE
+  }
+}
+
 // 3rd Party Tests
 TaskProvider s3ThirdPartyTest = tasks.register("s3ThirdPartyTest", Test) {
   SourceSetContainer sourceSets = project.getExtensions().getByType(SourceSetContainer.class);
@@ -298,6 +400,7 @@ TaskProvider s3ThirdPartyTest = tasks.register("s3ThirdPartyTest", Test) {
   systemProperty 'test.s3.account', s3PermanentAccessKey
   systemProperty 'test.s3.key', s3PermanentSecretKey
   systemProperty 'test.s3.bucket', s3PermanentBucket
+  systemProperty 'test.s3.region', s3PermanentRegion
   nonInputProperties.systemProperty 'test.s3.base', s3PermanentBasePath + "_third_party_tests_" + BuildParams.testSeed
   if (useFixture) {
     nonInputProperties.systemProperty 'test.s3.endpoint', "${-> fixtureAddress('minio-fixture', 'minio-fixture', '9000') }"
@@ -305,33 +408,183 @@ TaskProvider s3ThirdPartyTest = tasks.register("s3ThirdPartyTest", Test) {
 }
 tasks.named("check").configure { dependsOn(s3ThirdPartyTest) }
 
-thirdPartyAudit.ignoreMissingClasses(
-  // classes are missing
-  'javax.jms.Message',
-  'javax.servlet.ServletContextEvent',
-  'javax.servlet.ServletContextListener',
-  'org.apache.avalon.framework.logger.Logger',
-  'org.apache.log.Hierarchy',
-  'org.apache.log.Logger',
-  'software.amazon.ion.IonReader',
-  'software.amazon.ion.IonSystem',
-  'software.amazon.ion.IonType',
-  'software.amazon.ion.IonWriter',
-  'software.amazon.ion.Timestamp',
-  'software.amazon.ion.system.IonBinaryWriterBuilder',
-  'software.amazon.ion.system.IonSystemBuilder',
-  'software.amazon.ion.system.IonTextWriterBuilder',
-  'software.amazon.ion.system.IonWriterBuilder',
-  // We don't use the kms dependency
-  'com.amazonaws.services.kms.AWSKMS',
-  'com.amazonaws.services.kms.AWSKMSClient',
-  'com.amazonaws.services.kms.model.DecryptRequest',
-  'com.amazonaws.services.kms.model.DecryptResult',
-  'com.amazonaws.services.kms.model.EncryptRequest',
-  'com.amazonaws.services.kms.model.EncryptResult',
-  'com.amazonaws.services.kms.model.GenerateDataKeyRequest',
-  'com.amazonaws.services.kms.model.GenerateDataKeyResult'
-)
+thirdPartyAudit {
+  ignoreMissingClasses(
+    // classes are missing
+    'javax.jms.Message',
+    'javax.servlet.ServletContextEvent',
+    'javax.servlet.ServletContextListener',
+    'org.apache.avalon.framework.logger.Logger',
+    'org.apache.log.Hierarchy',
+    'org.apache.log.Logger',
+
+    // from io.netty.handler.ssl.OpenSslEngine (netty)
+    'io.netty.internal.tcnative.AsyncSSLPrivateKeyMethod',
+    'io.netty.internal.tcnative.AsyncTask',
+    'io.netty.internal.tcnative.Buffer',
+    'io.netty.internal.tcnative.CertificateCompressionAlgo',
+    'io.netty.internal.tcnative.Library',
+    'io.netty.internal.tcnative.ResultCallback',
+    'io.netty.internal.tcnative.SSL',
+    'io.netty.internal.tcnative.SSLContext',
+    'io.netty.internal.tcnative.SSLPrivateKeyMethod',
+    'io.netty.internal.tcnative.SSLSession',
+    'io.netty.internal.tcnative.SSLSessionCache',
+    'io.netty.internal.tcnative.CertificateCallback',
+    'io.netty.internal.tcnative.CertificateVerifier',
+    'io.netty.internal.tcnative.SessionTicketKey',
+    'io.netty.internal.tcnative.SniHostNameMatcher',
+
+    'com.aayushatharva.brotli4j.Brotli4jLoader',
+    'com.aayushatharva.brotli4j.decoder.DecoderJNI$Status',
+    'com.aayushatharva.brotli4j.decoder.DecoderJNI$Wrapper',
+    'com.aayushatharva.brotli4j.encoder.BrotliEncoderChannel',
+    'com.aayushatharva.brotli4j.encoder.Encoder$Mode',
+    'com.aayushatharva.brotli4j.encoder.Encoder$Parameters',
+
+    'com.google.protobuf.nano.CodedOutputByteBufferNano',
+    'com.google.protobuf.nano.MessageNano',
+
+    'com.ning.compress.BufferRecycler',
+    'com.ning.compress.lzf.ChunkDecoder',
+    'com.ning.compress.lzf.ChunkEncoder',
+    'com.ning.compress.lzf.LZFChunk',
+    'com.ning.compress.lzf.LZFEncoder',
+    'com.ning.compress.lzf.util.ChunkDecoderFactory',
+    'com.ning.compress.lzf.util.ChunkEncoderFactory',
+
+    'io.netty.internal.tcnative.AsyncSSLPrivateKeyMethod',
+    'io.netty.internal.tcnative.AsyncTask',
+
+    'io.netty.internal.tcnative.CertificateCallback',
+    'io.netty.internal.tcnative.CertificateVerifier',
+    'io.netty.internal.tcnative.ResultCallback',
+    'io.netty.internal.tcnative.SessionTicketKey',
+    'io.netty.internal.tcnative.SniHostNameMatcher',
+    'io.netty.internal.tcnative.SSL',
+    'io.netty.internal.tcnative.SSLSession',
+    'io.netty.internal.tcnative.SSLSessionCache',
+
+    'lzma.sdk.lzma.Encoder',
+    'net.jpountz.lz4.LZ4Compressor',
+    'net.jpountz.lz4.LZ4Factory',
+    'net.jpountz.lz4.LZ4FastDecompressor',
+    'net.jpountz.xxhash.XXHash32',
+    'net.jpountz.xxhash.XXHashFactory',
+
+    // from io.netty.handler.ssl.util.BouncyCastleSelfSignedCertGenerator (netty)
+    'org.bouncycastle.cert.X509v3CertificateBuilder',
+    'org.bouncycastle.cert.jcajce.JcaX509CertificateConverter',
+    'org.bouncycastle.operator.jcajce.JcaContentSignerBuilder',
+    'org.bouncycastle.openssl.PEMEncryptedKeyPair',
+    'org.bouncycastle.openssl.PEMParser',
+    'org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter',
+    'org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8DecryptorProviderBuilder',
+    'org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder',
+    'org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo',
+
+    'org.conscrypt.AllocatedBuffer',
+    'org.conscrypt.BufferAllocator',
+    'org.conscrypt.Conscrypt',
+    'org.conscrypt.HandshakeListener',
+
+    'org.eclipse.jetty.alpn.ALPN$ClientProvider',
+    'org.eclipse.jetty.alpn.ALPN$ServerProvider',
+    'org.eclipse.jetty.alpn.ALPN',
+
+    // from io.netty.handler.ssl.JettyNpnSslEngine (netty)
+    'org.eclipse.jetty.npn.NextProtoNego$ClientProvider',
+    'org.eclipse.jetty.npn.NextProtoNego$ServerProvider',
+    'org.eclipse.jetty.npn.NextProtoNego',
+
+    // from io.netty.handler.codec.marshalling.ChannelBufferByteInput (netty)
+    'org.jboss.marshalling.ByteInput',
+
+    // from io.netty.handler.codec.marshalling.ChannelBufferByteOutput (netty)
+    'org.jboss.marshalling.ByteOutput',
+
+    // from io.netty.handler.codec.marshalling.CompatibleMarshallingEncoder (netty)
+    'org.jboss.marshalling.Marshaller',
+
+    // from io.netty.handler.codec.marshalling.ContextBoundUnmarshallerProvider (netty)
+    'org.jboss.marshalling.MarshallerFactory',
+    'org.jboss.marshalling.MarshallingConfiguration',
+    'org.jboss.marshalling.Unmarshaller',
+
+    'org.slf4j.impl.StaticLoggerBinder',
+    'org.slf4j.impl.StaticMDCBinder',
+    'org.slf4j.impl.StaticMarkerBinder',
+    'reactor.blockhound.BlockHound$Builder',
+    'reactor.blockhound.integration.BlockHoundIntegration',
+
+    'software.amazon.awssdk.arns.Arn',
+    'software.amazon.awssdk.arns.ArnResource',
+    'software.amazon.awssdk.crt.CRT',
+    'software.amazon.awssdk.crt.auth.credentials.Credentials',
+    'software.amazon.awssdk.crt.auth.credentials.CredentialsProvider',
+    'software.amazon.awssdk.crt.auth.credentials.DelegateCredentialsProvider$DelegateCredentialsProviderBuilder',
+    'software.amazon.awssdk.crt.http.HttpHeader',
+    'software.amazon.awssdk.crt.http.HttpMonitoringOptions',
+    'software.amazon.awssdk.crt.http.HttpProxyOptions',
+    'software.amazon.awssdk.crt.http.HttpRequest',
+    'software.amazon.awssdk.crt.http.HttpRequestBodyStream',
+    'software.amazon.awssdk.crt.io.ClientBootstrap',
+    'software.amazon.awssdk.crt.io.ExponentialBackoffRetryOptions',
+    'software.amazon.awssdk.crt.io.StandardRetryOptions',
+    'software.amazon.awssdk.crt.io.TlsCipherPreference',
+    'software.amazon.awssdk.crt.io.TlsContext',
+    'software.amazon.awssdk.crt.io.TlsContextOptions',
+    'software.amazon.awssdk.crt.s3.ChecksumAlgorithm',
+    'software.amazon.awssdk.crt.s3.ChecksumConfig',
+    'software.amazon.awssdk.crt.s3.ChecksumConfig$ChecksumLocation',
+    'software.amazon.awssdk.crt.s3.ResumeToken',
+    'software.amazon.awssdk.crt.s3.S3Client',
+    'software.amazon.awssdk.crt.s3.S3ClientOptions',
+    'software.amazon.awssdk.crt.s3.S3FinishedResponseContext',
+    'software.amazon.awssdk.crt.s3.S3MetaRequest',
+    'software.amazon.awssdk.crt.s3.S3MetaRequestOptions',
+    'software.amazon.awssdk.crt.s3.S3MetaRequestOptions$MetaRequestType',
+    'software.amazon.awssdk.crt.s3.S3MetaRequestResponseHandler',
+    'software.amazon.awssdk.crtcore.CrtConfigurationUtils',
+    'software.amazon.awssdk.crtcore.CrtConnectionHealthConfiguration',
+    'software.amazon.awssdk.crtcore.CrtConnectionHealthConfiguration$Builder',
+    'software.amazon.awssdk.crtcore.CrtConnectionHealthConfiguration$DefaultBuilder',
+    'software.amazon.awssdk.crtcore.CrtProxyConfiguration',
+    'software.amazon.awssdk.crtcore.CrtProxyConfiguration$Builder',
+    'software.amazon.awssdk.crtcore.CrtProxyConfiguration$DefaultBuilder',
+    'software.amazon.eventstream.HeaderValue',
+    'software.amazon.eventstream.Message',
+    'software.amazon.eventstream.MessageDecoder'
+  )
+
+  ignoreViolations (
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$1',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$2',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$3',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$4',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$5',
+
+    'io.netty.util.internal.PlatformDependent0',
+    'io.netty.util.internal.PlatformDependent0$1',
+    'io.netty.util.internal.PlatformDependent0$2',
+    'io.netty.util.internal.PlatformDependent0$3',
+    'io.netty.util.internal.PlatformDependent0$4',
+    'io.netty.util.internal.PlatformDependent0$6',
+
+    'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueConsumerNodeRef',
+    'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueProducerNodeRef',
+    'io.netty.util.internal.shaded.org.jctools.queues.BaseMpscLinkedArrayQueueColdProducerFields',
+    'io.netty.util.internal.shaded.org.jctools.queues.BaseMpscLinkedArrayQueueConsumerFields',
+    'io.netty.util.internal.shaded.org.jctools.queues.BaseMpscLinkedArrayQueueProducerFields',
+    'io.netty.util.internal.shaded.org.jctools.queues.LinkedQueueNode',
+    'io.netty.util.internal.shaded.org.jctools.queues.MpscArrayQueueConsumerIndexField',
+    'io.netty.util.internal.shaded.org.jctools.queues.MpscArrayQueueProducerIndexField',
+    'io.netty.util.internal.shaded.org.jctools.queues.MpscArrayQueueProducerLimitField',
+    'io.netty.util.internal.shaded.org.jctools.util.UnsafeAccess',
+    'io.netty.util.internal.shaded.org.jctools.util.UnsafeRefArrayAccess',
+  )
+}
 
 // jarhell with jdk (intentionally, because jaxb was removed from default modules in java 9)
 if (BuildParams.runtimeJavaVersion <= JavaVersion.VERSION_1_8) {
diff --git a/plugins/repository-s3/config/repository-s3/log4j2.properties b/plugins/repository-s3/config/repository-s3/log4j2.properties
index 7263bbcba521c..ceb9a546b9b08 100644
--- a/plugins/repository-s3/config/repository-s3/log4j2.properties
+++ b/plugins/repository-s3/config/repository-s3/log4j2.properties
@@ -9,17 +9,17 @@
 # GitHub history for details.
 #
 
-logger.com_amazonaws.name = com.amazonaws
+logger.com_amazonaws.name = software.amazon.awssdk
 logger.com_amazonaws.level = warn
 
-logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.name = com.amazonaws.jmx.SdkMBeanRegistrySupport
+logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.name = software.amazon.awssdk.jmx.SdkMBeanRegistrySupport
 logger.com_amazonaws_jmx_SdkMBeanRegistrySupport.level = error
 
-logger.com_amazonaws_metrics_AwsSdkMetrics.name = com.amazonaws.metrics.AwsSdkMetrics
+logger.com_amazonaws_metrics_AwsSdkMetrics.name = software.amazon.awssdk.metrics.AwsSdkMetrics
 logger.com_amazonaws_metrics_AwsSdkMetrics.level = error
 
-logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.name = com.amazonaws.auth.profile.internal.BasicProfileConfigFileLoader
+logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.name = software.amazon.awssdk.auth.profile.internal.BasicProfileConfigFileLoader
 logger.com_amazonaws_auth_profile_internal_BasicProfileConfigFileLoader.level = error
 
-logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.name = com.amazonaws.services.s3.internal.UseArnRegionResolver
+logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.name = software.amazon.awssdk.services.s3.internal.UseArnRegionResolver
 logger.com_amazonaws_services_s3_internal_UseArnRegionResolver.level = error
diff --git a/plugins/repository-s3/licenses/annotations-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/annotations-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5a626eeb5725b
--- /dev/null
+++ b/plugins/repository-s3/licenses/annotations-2.20.55.jar.sha1
@@ -0,0 +1 @@
+330e9d0e5f2401fffba5afe30f3740f400e8308d
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/annotations-LICENSE.txt b/plugins/repository-s3/licenses/annotations-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/annotations-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/annotations-NOTICE.txt b/plugins/repository-s3/licenses/annotations-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/annotations-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/apache-client-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/apache-client-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..3ee96bb6e4076
--- /dev/null
+++ b/plugins/repository-s3/licenses/apache-client-2.20.55.jar.sha1
@@ -0,0 +1 @@
+5c149885667d41a306769505cfa481cfddf6f113
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/apache-client-LICENSE.txt b/plugins/repository-s3/licenses/apache-client-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/apache-client-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/apache-client-NOTICE.txt b/plugins/repository-s3/licenses/apache-client-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/apache-client-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/auth-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/auth-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..010464bdf9fd1
--- /dev/null
+++ b/plugins/repository-s3/licenses/auth-2.20.55.jar.sha1
@@ -0,0 +1 @@
+e21f00a8a2096d5044f3eff176944256e01a175e
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/auth-LICENSE.txt b/plugins/repository-s3/licenses/auth-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/auth-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/auth-NOTICE.txt b/plugins/repository-s3/licenses/auth-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/auth-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/aws-core-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/aws-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4b4ee1db864a8
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+734427c2cece98a8cb90871b78d2311e4a7ef746
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-core-LICENSE.txt b/plugins/repository-s3/licenses/aws-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/aws-core-NOTICE.txt b/plugins/repository-s3/licenses/aws-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/aws-java-sdk-LICENSE.txt b/plugins/repository-s3/licenses/aws-java-sdk-LICENSE.txt
deleted file mode 100644
index 98d1f9319f374..0000000000000
--- a/plugins/repository-s3/licenses/aws-java-sdk-LICENSE.txt
+++ /dev/null
@@ -1,63 +0,0 @@
-Apache License
-Version 2.0, January 2004
-
-TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-1. Definitions.
-
-"License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document.
-
-"Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License.
-
-"Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity.
-
-"You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License.
-
-"Source" form shall mean the preferred form for making modifications, including but not limited to software source code, documentation source, and configuration files.
-
-"Object" form shall mean any form resulting from mechanical transformation or translation of a Source form, including but not limited to compiled object code, generated documentation, and conversions to other media types.
-
-"Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below).
-
-"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.
-
-"Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner. For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Licensor or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as "Not a Contribution."
-
-"Contributor" shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work.
-
-2. Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.
-
-3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
-
-4. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:
-
-   1.   You must give any other recipients of the Work or Derivative Works a copy of this License; and
-   2.   You must cause any modified files to carry prominent notices stating that You changed the files; and
-   3.   You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works; and
-   4.   If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License.
-
-You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.
-
-5. Submission of Contributions. Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions.
-
-6. Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.
-
-7. Disclaimer of Warranty. Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License.
-
-8. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.
-
-9. Accepting Warranty or Additional Liability. While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability.
-
-END OF TERMS AND CONDITIONS
-
-Note: Other license terms may apply to certain, identified software files contained within or distributed with the accompanying software if such terms are included in the directory containing the accompanying software. Such other license terms will then apply in lieu of the terms of the software license above.
-
-JSON processing code subject to the JSON License from JSON.org:
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-
-The Software shall be used for Good, not Evil.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/plugins/repository-s3/licenses/aws-java-sdk-NOTICE.txt b/plugins/repository-s3/licenses/aws-java-sdk-NOTICE.txt
deleted file mode 100644
index 565bd6085c71a..0000000000000
--- a/plugins/repository-s3/licenses/aws-java-sdk-NOTICE.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-AWS SDK for Java
-Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
-
-This product includes software developed by
-Amazon Technologies, Inc (http://www.amazon.com/).
-
-**********************
-THIRD PARTY COMPONENTS
-**********************
-This software includes third party software subject to the following copyrights:
-- XML parsing and utility functions from JetS3t - Copyright 2006-2009 James Murty.
-- JSON parsing and utility functions from JSON.org - Copyright 2002 JSON.org.
-- PKCS#1 PEM encoded private key parsing and utility functions from oauth.googlecode.com - Copyright 1998-2010 AOL Inc.
-
-The licenses for these third party components are included in LICENSE.txt
diff --git a/plugins/repository-s3/licenses/aws-java-sdk-core-1.11.749.jar.sha1 b/plugins/repository-s3/licenses/aws-java-sdk-core-1.11.749.jar.sha1
deleted file mode 100644
index 7bc18d6d4f681..0000000000000
--- a/plugins/repository-s3/licenses/aws-java-sdk-core-1.11.749.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1da5c1549295cfeebc67fc1c7539785a9441755b
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-java-sdk-s3-1.11.749.jar.sha1 b/plugins/repository-s3/licenses/aws-java-sdk-s3-1.11.749.jar.sha1
deleted file mode 100644
index af794dc59dd7f..0000000000000
--- a/plugins/repository-s3/licenses/aws-java-sdk-s3-1.11.749.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-7d069f82723907ccdbd0c91ef0ac76046f5c9652
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-json-protocol-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/aws-json-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..45a88305c1928
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-json-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a52731c86b974aefa5bbb1c545f407811a0163b1
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-json-protocol-LICENSE.txt b/plugins/repository-s3/licenses/aws-json-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-json-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/aws-json-protocol-NOTICE.txt b/plugins/repository-s3/licenses/aws-json-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-json-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/aws-query-protocol-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/aws-query-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..ba5f43378730c
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-query-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+ac116215cc85366f0bdffee53b4c21e7a7fe03ef
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-query-protocol-LICENSE.txt b/plugins/repository-s3/licenses/aws-query-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-query-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/aws-query-protocol-NOTICE.txt b/plugins/repository-s3/licenses/aws-query-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-query-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/aws-xml-protocol-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/aws-xml-protocol-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..fc65ee07c40c6
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-xml-protocol-2.20.55.jar.sha1
@@ -0,0 +1 @@
+6a3b5f607ece38536f17d869b82c669c6339f9ad
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/aws-xml-protocol-LICENSE.txt b/plugins/repository-s3/licenses/aws-xml-protocol-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-xml-protocol-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/aws-xml-protocol-NOTICE.txt b/plugins/repository-s3/licenses/aws-xml-protocol-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/aws-xml-protocol-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/commons-codec-1.13.jar.sha1 b/plugins/repository-s3/licenses/commons-codec-1.13.jar.sha1
deleted file mode 100644
index 66b72c414d63a..0000000000000
--- a/plugins/repository-s3/licenses/commons-codec-1.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3f18e1aa31031d89db6f01ba05d501258ce69d2c
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/commons-codec-1.15.jar.sha1 b/plugins/repository-s3/licenses/commons-codec-1.15.jar.sha1
new file mode 100644
index 0000000000000..62d99837b87e1
--- /dev/null
+++ b/plugins/repository-s3/licenses/commons-codec-1.15.jar.sha1
@@ -0,0 +1 @@
+49d94806b6e3dc933dacbd8acb0fdbab8ebd1e5d
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/commons-logging-1.1.3.jar.sha1 b/plugins/repository-s3/licenses/commons-logging-1.1.3.jar.sha1
deleted file mode 100644
index c8756c438320f..0000000000000
--- a/plugins/repository-s3/licenses/commons-logging-1.1.3.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f
diff --git a/plugins/repository-s3/licenses/commons-logging-1.2.jar.sha1 b/plugins/repository-s3/licenses/commons-logging-1.2.jar.sha1
new file mode 100644
index 0000000000000..f40f0242448e8
--- /dev/null
+++ b/plugins/repository-s3/licenses/commons-logging-1.2.jar.sha1
@@ -0,0 +1 @@
+4bfc12adfe4842bf07b657f0369c4cb522955686
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/commons-logging-LICENSE.txt b/plugins/repository-s3/licenses/commons-logging-LICENSE.txt
index 57bc88a15a0ee..d645695673349 100644
--- a/plugins/repository-s3/licenses/commons-logging-LICENSE.txt
+++ b/plugins/repository-s3/licenses/commons-logging-LICENSE.txt
@@ -1,3 +1,4 @@
+
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -199,4 +200,3 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
-
diff --git a/plugins/repository-s3/licenses/commons-logging-NOTICE.txt b/plugins/repository-s3/licenses/commons-logging-NOTICE.txt
index 72eb32a902458..d3d6e140ce4f3 100644
--- a/plugins/repository-s3/licenses/commons-logging-NOTICE.txt
+++ b/plugins/repository-s3/licenses/commons-logging-NOTICE.txt
@@ -1,5 +1,5 @@
-Apache Commons CLI
-Copyright 2001-2009 The Apache Software Foundation
+Apache Commons Logging
+Copyright 2003-2014 The Apache Software Foundation
 
-This product includes software developed by
+This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
diff --git a/plugins/repository-s3/licenses/endpoints-spi-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/endpoints-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5bc0e31166c77
--- /dev/null
+++ b/plugins/repository-s3/licenses/endpoints-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+085f82038ee86a7d6cd568fe7edd842978d92de3
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/endpoints-spi-LICENSE.txt b/plugins/repository-s3/licenses/endpoints-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/endpoints-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/endpoints-spi-NOTICE.txt b/plugins/repository-s3/licenses/endpoints-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/endpoints-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/http-client-spi-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/http-client-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..523cf43dcb2e9
--- /dev/null
+++ b/plugins/repository-s3/licenses/http-client-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+34f9b10c1a46038a0ceebdd750ba3a413a862ceb
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/http-client-spi-LICENSE.txt b/plugins/repository-s3/licenses/http-client-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/http-client-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/http-client-spi-NOTICE.txt b/plugins/repository-s3/licenses/http-client-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/http-client-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/httpclient-4.5.13.jar.sha1 b/plugins/repository-s3/licenses/httpclient-4.5.13.jar.sha1
deleted file mode 100644
index 3281e21595b39..0000000000000
--- a/plugins/repository-s3/licenses/httpclient-4.5.13.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e5f6cae5ca7ecaac1ec2827a9e2d65ae2869cada
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/httpclient-4.5.14.jar.sha1 b/plugins/repository-s3/licenses/httpclient-4.5.14.jar.sha1
new file mode 100644
index 0000000000000..66e05851c2e3c
--- /dev/null
+++ b/plugins/repository-s3/licenses/httpclient-4.5.14.jar.sha1
@@ -0,0 +1 @@
+1194890e6f56ec29177673f2f12d0b8e627dec98
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/httpcore-4.4.12.jar.sha1 b/plugins/repository-s3/licenses/httpcore-4.4.12.jar.sha1
deleted file mode 100644
index 3c046171b30da..0000000000000
--- a/plugins/repository-s3/licenses/httpcore-4.4.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-21ebaf6d532bc350ba95bd81938fa5f0e511c132
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/httpcore-4.4.16.jar.sha1 b/plugins/repository-s3/licenses/httpcore-4.4.16.jar.sha1
new file mode 100644
index 0000000000000..172110694b5bd
--- /dev/null
+++ b/plugins/repository-s3/licenses/httpcore-4.4.16.jar.sha1
@@ -0,0 +1 @@
+51cf043c87253c9f58b539c9f7e44c8894223850
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/jackson-annotations-2.13.2.jar.sha1 b/plugins/repository-s3/licenses/jackson-annotations-2.13.2.jar.sha1
deleted file mode 100644
index ecd3fb49d5b12..0000000000000
--- a/plugins/repository-s3/licenses/jackson-annotations-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ec18851f1976d5b810ae1a5fcc32520d2d38f77a
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/jackson-annotations-2.15.2.jar.sha1 b/plugins/repository-s3/licenses/jackson-annotations-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f63416ddb8ceb
--- /dev/null
+++ b/plugins/repository-s3/licenses/jackson-annotations-2.15.2.jar.sha1
@@ -0,0 +1 @@
+4724a65ac8e8d156a24898d50fd5dbd3642870b8
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/jackson-databind-2.13.2.jar.sha1 b/plugins/repository-s3/licenses/jackson-databind-2.13.2.jar.sha1
deleted file mode 100644
index 5d356f3fd045f..0000000000000
--- a/plugins/repository-s3/licenses/jackson-databind-2.13.2.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-926e48c451166a291f1ce6c6276d9abbefa7c00f
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/jackson-databind-2.15.2.jar.sha1 b/plugins/repository-s3/licenses/jackson-databind-2.15.2.jar.sha1
new file mode 100644
index 0000000000000..f16d80af8dce6
--- /dev/null
+++ b/plugins/repository-s3/licenses/jackson-databind-2.15.2.jar.sha1
@@ -0,0 +1 @@
+9353b021f10c307c00328f52090de2bdb4b6ff9c
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/jmespath-java-1.11.749.jar.sha1 b/plugins/repository-s3/licenses/jmespath-java-1.11.749.jar.sha1
deleted file mode 100644
index 3467802d074c7..0000000000000
--- a/plugins/repository-s3/licenses/jmespath-java-1.11.749.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-778866bc557dba508ee0eab2a0c5bfde468e49e6
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/json-utils-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/json-utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..a19b00e62f8b5
--- /dev/null
+++ b/plugins/repository-s3/licenses/json-utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+cd6710900e3190eac4c4496ae529ce08680dd320
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/json-utils-LICENSE.txt b/plugins/repository-s3/licenses/json-utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/json-utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/json-utils-NOTICE.txt b/plugins/repository-s3/licenses/json-utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/json-utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/log4j-1.2-api-2.17.1.jar.sha1 b/plugins/repository-s3/licenses/log4j-1.2-api-2.17.1.jar.sha1
deleted file mode 100644
index 23aa5c60bd596..0000000000000
--- a/plugins/repository-s3/licenses/log4j-1.2-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-db3a7e7f07e878b92ac4a8f1100bee8325d5713a
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/log4j-1.2-api-2.20.0.jar.sha1 b/plugins/repository-s3/licenses/log4j-1.2-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..9829576d38ce0
--- /dev/null
+++ b/plugins/repository-s3/licenses/log4j-1.2-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+689151374756cb809cb029f2501015bdc7733179
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/metrics-spi-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/metrics-spi-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..db6701d87892a
--- /dev/null
+++ b/plugins/repository-s3/licenses/metrics-spi-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8a0eae705b27465516f3b09cc9918e40963d534d
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/metrics-spi-LICENSE.txt b/plugins/repository-s3/licenses/metrics-spi-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/metrics-spi-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/metrics-spi-NOTICE.txt b/plugins/repository-s3/licenses/metrics-spi-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/metrics-spi-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/netty-LICENSE.txt b/plugins/repository-s3/licenses/netty-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/netty-NOTICE.txt b/plugins/repository-s3/licenses/netty-NOTICE.txt
new file mode 100644
index 0000000000000..5bbf91a14de23
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-NOTICE.txt
@@ -0,0 +1,116 @@
+
+                            The Netty Project
+                            =================
+
+Please visit the Netty web site for more information:
+
+  * http://netty.io/
+
+Copyright 2011 The Netty Project
+
+The Netty Project licenses this file to you under the Apache License,
+version 2.0 (the "License"); you may not use this file except in compliance
+with the License. You may obtain a copy of the License at:
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+License for the specific language governing permissions and limitations
+under the License.
+
+Also, please refer to each LICENSE.<component>.txt file, which is located in
+the 'license' directory of the distribution file, for the license terms of the
+components that this product depends on.
+
+-------------------------------------------------------------------------------
+This product contains the extensions to Java Collections Framework which has
+been derived from the works by JSR-166 EG, Doug Lea, and Jason T. Greene:
+
+  * LICENSE:
+    * license/LICENSE.jsr166y.txt (Public Domain)
+  * HOMEPAGE:
+    * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/
+    * http://viewvc.jboss.org/cgi-bin/viewvc.cgi/jbosscache/experimental/jsr166/
+
+This product contains a modified version of Robert Harder's Public Domain
+Base64 Encoder and Decoder, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.base64.txt (Public Domain)
+  * HOMEPAGE:
+    * http://iharder.sourceforge.net/current/java/base64/
+
+This product contains a modified version of 'JZlib', a re-implementation of
+zlib in pure Java, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.jzlib.txt (BSD Style License)
+  * HOMEPAGE:
+    * http://www.jcraft.com/jzlib/
+
+This product contains a modified version of 'Webbit', a Java event based
+WebSocket and HTTP server:
+
+  * LICENSE:
+    * license/LICENSE.webbit.txt (BSD License)
+  * HOMEPAGE:
+    * https://github.com/joewalnes/webbit
+
+This product optionally depends on 'Protocol Buffers', Google's data
+interchange format, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.protobuf.txt (New BSD License)
+  * HOMEPAGE:
+    * http://code.google.com/p/protobuf/
+
+This product optionally depends on 'Bouncy Castle Crypto APIs' to generate
+a temporary self-signed X.509 certificate when the JVM does not provide the
+equivalent functionality.  It can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.bouncycastle.txt (MIT License)
+  * HOMEPAGE:
+    * http://www.bouncycastle.org/
+
+This product optionally depends on 'SLF4J', a simple logging facade for Java,
+which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.slf4j.txt (MIT License)
+  * HOMEPAGE:
+    * http://www.slf4j.org/
+
+This product optionally depends on 'Apache Commons Logging', a logging
+framework, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.commons-logging.txt (Apache License 2.0)
+  * HOMEPAGE:
+    * http://commons.apache.org/logging/
+
+This product optionally depends on 'Apache Log4J', a logging framework,
+which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.log4j.txt (Apache License 2.0)
+  * HOMEPAGE:
+    * http://logging.apache.org/log4j/
+
+This product optionally depends on 'JBoss Logging', a logging framework,
+which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.jboss-logging.txt (GNU LGPL 2.1)
+  * HOMEPAGE:
+    * http://anonsvn.jboss.org/repos/common/common-logging-spi/
+
+This product optionally depends on 'Apache Felix', an open source OSGi
+framework implementation, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.felix.txt (Apache License 2.0)
+  * HOMEPAGE:
+    * http://felix.apache.org/
diff --git a/plugins/repository-s3/licenses/netty-buffer-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-buffer-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..5b393be40e945
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-buffer-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9f02dcb9b15a647a56af210dffdc294a57922fb0
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-codec-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-codec-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..45ea27d29a183
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-codec-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9984cbd6e5d55c768f198e975d8aaf7fd42a4602
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-codec-http-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-codec-http-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6bb7fcd68b272
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-codec-http-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+7142095066eaebd5f29b88c41af7b383b6a953f6
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-codec-http2-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-codec-http2-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..f9bdefc6dd965
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-codec-http2-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+c5a3481c4bb9732a3a94fb63cf916141a1a14669
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-common-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..d53adfa649f5f
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+278f6dfa49d6bd75c40ae1470eb165716f87dce0
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-handler-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-handler-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..258f7c957dda0
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-handler-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+742693761d7ea4c038bccfda96bb38194720b80d
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-nio-client-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/netty-nio-client-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..489f18e0bceaa
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-nio-client-2.20.55.jar.sha1
@@ -0,0 +1 @@
+4c269571ad2fb19851ebd7c7856aa2975fe0bab3
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-resolver-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-resolver-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..b8bc0a4370f58
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-resolver-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+080e45397d9d5b134477de3ffd0f94283b908621
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-transport-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-transport-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..247975e0a64c7
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-transport-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9ca2e3ae19a6713b749df154622115f480b6716c
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-transport-classes-epoll-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-transport-classes-epoll-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..75b64ad4197d8
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-transport-classes-epoll-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+961bd5b8d97ea6a07168176462f398089a24b5c8
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1 b/plugins/repository-s3/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6b7b66ea768e3
--- /dev/null
+++ b/plugins/repository-s3/licenses/netty-transport-native-unix-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+cb0fc6c31c387404212949c57950b5d72ce908b9
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/profiles-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/profiles-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..b7104cf0939e6
--- /dev/null
+++ b/plugins/repository-s3/licenses/profiles-2.20.55.jar.sha1
@@ -0,0 +1 @@
+959aad08b2f24057bf286c761b49e3af31a0a623
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/profiles-LICENSE.txt b/plugins/repository-s3/licenses/profiles-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/profiles-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/profiles-NOTICE.txt b/plugins/repository-s3/licenses/profiles-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/profiles-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/protocol-core-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/protocol-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..4dee45f4d9dd3
--- /dev/null
+++ b/plugins/repository-s3/licenses/protocol-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+0935e3ab32962a890f1d13bf39ba2167d9d692f9
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/protocol-core-LICENSE.txt b/plugins/repository-s3/licenses/protocol-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/protocol-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/protocol-core-NOTICE.txt b/plugins/repository-s3/licenses/protocol-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/protocol-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/reactive-streams-1.0.4.jar.sha1 b/plugins/repository-s3/licenses/reactive-streams-1.0.4.jar.sha1
new file mode 100644
index 0000000000000..45a80e3f7e361
--- /dev/null
+++ b/plugins/repository-s3/licenses/reactive-streams-1.0.4.jar.sha1
@@ -0,0 +1 @@
+3864a1320d97d7b045f729a326e1e077661f31b7
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/reactive-streams-LICENSE.txt b/plugins/repository-s3/licenses/reactive-streams-LICENSE.txt
new file mode 100644
index 0000000000000..1e3c7e7c77495
--- /dev/null
+++ b/plugins/repository-s3/licenses/reactive-streams-LICENSE.txt
@@ -0,0 +1,21 @@
+MIT No Attribution
+
+Copyright 2014 Reactive Streams
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/reactive-streams-NOTICE.txt b/plugins/repository-s3/licenses/reactive-streams-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/repository-s3/licenses/regions-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/regions-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..993fc2f97de62
--- /dev/null
+++ b/plugins/repository-s3/licenses/regions-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a117c19b4a30e902f4f1cc4bef6b5c10cc9aef31
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/regions-LICENSE.txt b/plugins/repository-s3/licenses/regions-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/regions-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/regions-NOTICE.txt b/plugins/repository-s3/licenses/regions-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/regions-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/s3-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/s3-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..b7f3157995aa6
--- /dev/null
+++ b/plugins/repository-s3/licenses/s3-2.20.55.jar.sha1
@@ -0,0 +1 @@
+69e7df4c7c170867dc246c0205c5e0b6099e8a6f
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/s3-LICENSE.txt b/plugins/repository-s3/licenses/s3-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/s3-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/s3-NOTICE.txt b/plugins/repository-s3/licenses/s3-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/s3-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/sdk-core-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/sdk-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..5f12be9c08c5b
--- /dev/null
+++ b/plugins/repository-s3/licenses/sdk-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+8f2347feaf2575560ca89a2caa8d0243dbeb17a9
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/sdk-core-LICENSE.txt b/plugins/repository-s3/licenses/sdk-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/sdk-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/sdk-core-NOTICE.txt b/plugins/repository-s3/licenses/sdk-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/sdk-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/signer-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/signer-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..ec53fa0db623e
--- /dev/null
+++ b/plugins/repository-s3/licenses/signer-2.20.55.jar.sha1
@@ -0,0 +1 @@
+a44e55775ae429931287f81a634eeb67bd607a9f
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/signer-LICENSE.txt b/plugins/repository-s3/licenses/signer-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/signer-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/signer-NOTICE.txt b/plugins/repository-s3/licenses/signer-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/signer-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/slf4j-api-1.7.36.jar.sha1 b/plugins/repository-s3/licenses/slf4j-api-1.7.36.jar.sha1
new file mode 100644
index 0000000000000..77b9917528382
--- /dev/null
+++ b/plugins/repository-s3/licenses/slf4j-api-1.7.36.jar.sha1
@@ -0,0 +1 @@
+6c62681a2f655b49963a5983b8b0950a6120ae14
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/slf4j-api-LICENSE.txt b/plugins/repository-s3/licenses/slf4j-api-LICENSE.txt
new file mode 100644
index 0000000000000..8fda22f4d72f6
--- /dev/null
+++ b/plugins/repository-s3/licenses/slf4j-api-LICENSE.txt
@@ -0,0 +1,21 @@
+Copyright (c) 2004-2014 QOS.ch
+All rights reserved.
+
+Permission is hereby granted, free  of charge, to any person obtaining
+a  copy  of this  software  and  associated  documentation files  (the
+"Software"), to  deal in  the Software without  restriction, including
+without limitation  the rights to  use, copy, modify,  merge, publish,
+distribute,  sublicense, and/or sell  copies of  the Software,  and to
+permit persons to whom the Software  is furnished to do so, subject to
+the following conditions:
+
+The  above  copyright  notice  and  this permission  notice  shall  be
+included in all copies or substantial portions of the Software.
+
+THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
+EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
+MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/plugins/repository-s3/licenses/slf4j-api-NOTICE.txt b/plugins/repository-s3/licenses/slf4j-api-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/repository-s3/licenses/sts-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/sts-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..9f4bbdd0f22ad
--- /dev/null
+++ b/plugins/repository-s3/licenses/sts-2.20.55.jar.sha1
@@ -0,0 +1 @@
+adc350996b6f8481a32c8e73598138fc32826584
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/sts-LICENSE.txt b/plugins/repository-s3/licenses/sts-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/sts-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/sts-NOTICE.txt b/plugins/repository-s3/licenses/sts-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/sts-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/third-party-jackson-core-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/third-party-jackson-core-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..e7eebbb98f1fe
--- /dev/null
+++ b/plugins/repository-s3/licenses/third-party-jackson-core-2.20.55.jar.sha1
@@ -0,0 +1 @@
+956912f26056fc7d46b2db566362fe5f7a8c0e14
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/third-party-jackson-core-LICENSE.txt b/plugins/repository-s3/licenses/third-party-jackson-core-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/third-party-jackson-core-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/third-party-jackson-core-NOTICE.txt b/plugins/repository-s3/licenses/third-party-jackson-core-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/third-party-jackson-core-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/licenses/utils-2.20.55.jar.sha1 b/plugins/repository-s3/licenses/utils-2.20.55.jar.sha1
new file mode 100644
index 0000000000000..fc4cde604e33c
--- /dev/null
+++ b/plugins/repository-s3/licenses/utils-2.20.55.jar.sha1
@@ -0,0 +1 @@
+d3e1bbbc19795eadbeb4dd963a94647576644097
\ No newline at end of file
diff --git a/plugins/repository-s3/licenses/utils-LICENSE.txt b/plugins/repository-s3/licenses/utils-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/repository-s3/licenses/utils-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/repository-s3/licenses/utils-NOTICE.txt b/plugins/repository-s3/licenses/utils-NOTICE.txt
new file mode 100644
index 0000000000000..d2bc5723e9aea
--- /dev/null
+++ b/plugins/repository-s3/licenses/utils-NOTICE.txt
@@ -0,0 +1,14 @@
+OpenSearch (https://opensearch.org/)
+Copyright OpenSearch Contributors
+
+This product includes software developed by
+Elasticsearch (http://www.elastic.co).
+Copyright 2009-2018 Elasticsearch
+
+This product includes software developed by The Apache Software
+Foundation (http://www.apache.org/).
+
+This product includes software developed by
+Joda.org (http://www.joda.org/).
+
+
diff --git a/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3BlobStoreRepositoryTests.java b/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3BlobStoreRepositoryTests.java
index e31a9f8cf3856..4bd67e66ebcbd 100644
--- a/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3BlobStoreRepositoryTests.java
+++ b/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3BlobStoreRepositoryTests.java
@@ -31,35 +31,36 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.http.AmazonHttpClient;
 import com.sun.net.httpserver.Headers;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
-import fixture.s3.S3HttpHandler;
+
+import software.amazon.awssdk.core.internal.http.pipeline.stages.ApplyTransactionIdStage;
+
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.PlainActionFuture;
-
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.RepositoryData;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.OpenSearchMockAPIBasedRepositoryIntegTestCase;
+import org.opensearch.repositories.s3.utils.AwsRequestSigner;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.snapshots.mockstore.BlobStoreWrapper;
@@ -68,16 +69,18 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
+import fixture.s3.S3HttpHandler;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.lessThan;
-import static org.hamcrest.Matchers.startsWith;
 
 @SuppressForbidden(reason = "this test uses a HttpServer to emulate an S3 endpoint")
 // Need to set up a new cluster for each test because cluster settings use randomized authentication settings
@@ -86,22 +89,27 @@ public class S3BlobStoreRepositoryTests extends OpenSearchMockAPIBasedRepository
 
     private static final TimeValue TEST_COOLDOWN_PERIOD = TimeValue.timeValueSeconds(10L);
 
-    private String region;
+    private final String region = "test-region";
     private String signerOverride;
+    private String previousOpenSearchPathConf;
 
     @Override
     public void setUp() throws Exception {
-        if (randomBoolean()) {
-            region = "test-region";
-        }
-        if (region != null && randomBoolean()) {
-            signerOverride = randomFrom("AWS3SignerType", "AWS4SignerType");
-        } else if (randomBoolean()) {
-            signerOverride = "AWS3SignerType";
-        }
+        signerOverride = AwsRequestSigner.VERSION_FOUR_SIGNER.getName();
+        previousOpenSearchPathConf = SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", "config"));
         super.setUp();
     }
 
+    @Override
+    public void tearDown() throws Exception {
+        if (previousOpenSearchPathConf != null) {
+            SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", previousOpenSearchPathConf));
+        } else {
+            SocketAccess.doPrivileged(() -> System.clearProperty("opensearch.path.conf"));
+        }
+        super.tearDown();
+    }
+
     @Override
     protected String repositoryType() {
         return S3Repository.TYPE;
@@ -146,15 +154,15 @@ protected Settings nodeSettings(int nodeOrdinal) {
             .put(S3ClientSettings.DISABLE_CHUNKED_ENCODING.getConcreteSettingForNamespace("test").getKey(), true)
             // Disable request throttling because some random values in tests might generate too many failures for the S3 client
             .put(S3ClientSettings.USE_THROTTLE_RETRIES_SETTING.getConcreteSettingForNamespace("test").getKey(), false)
+            .put(S3ClientSettings.PROXY_TYPE_SETTING.getConcreteSettingForNamespace("test").getKey(), ProxySettings.ProxyType.DIRECT)
             .put(super.nodeSettings(nodeOrdinal))
             .setSecureSettings(secureSettings);
 
         if (signerOverride != null) {
             builder.put(S3ClientSettings.SIGNER_OVERRIDE.getConcreteSettingForNamespace("test").getKey(), signerOverride);
         }
-        if (region != null) {
-            builder.put(S3ClientSettings.REGION.getConcreteSettingForNamespace("test").getKey(), region);
-        }
+
+        builder.put(S3ClientSettings.REGION.getConcreteSettingForNamespace("test").getKey(), region);
         return builder.build();
     }
 
@@ -172,7 +180,7 @@ public void testEnforcedCooldownPeriod() throws IOException {
             .get()
             .getSnapshotInfo()
             .snapshotId();
-        final RepositoriesService repositoriesService = internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class);
+        final RepositoriesService repositoriesService = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class);
         final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(repoName);
         final RepositoryData repositoryData = getRepositoryData(repository);
         final RepositoryData modifiedRepositoryData = repositoryData.withVersions(
@@ -213,8 +221,8 @@ public void testEnforcedCooldownPeriod() throws IOException {
      */
     public static class TestS3RepositoryPlugin extends S3RepositoryPlugin {
 
-        public TestS3RepositoryPlugin(final Settings settings) {
-            super(settings);
+        public TestS3RepositoryPlugin(final Settings settings, final Path configPath) {
+            super(settings, configPath);
         }
 
         @Override
@@ -231,7 +239,7 @@ protected S3Repository createRepository(
             ClusterService clusterService,
             RecoverySettings recoverySettings
         ) {
-            return new S3Repository(metadata, registry, service, clusterService, recoverySettings) {
+            return new S3Repository(metadata, registry, service, clusterService, recoverySettings, null, null, null, null, false) {
 
                 @Override
                 public BlobStore blobStore() {
@@ -269,14 +277,11 @@ public void handle(final HttpExchange exchange) throws IOException {
 
         private void validateAuthHeader(HttpExchange exchange) {
             final String authorizationHeaderV4 = exchange.getRequestHeaders().getFirst("Authorization");
-            final String authorizationHeaderV3 = exchange.getRequestHeaders().getFirst("X-amzn-authorization");
 
-            if ("AWS3SignerType".equals(signerOverride)) {
-                assertThat(authorizationHeaderV3, startsWith("AWS3"));
-            } else if ("AWS4SignerType".equals(signerOverride)) {
+            if ("AWS4SignerType".equals(signerOverride)) {
                 assertThat(authorizationHeaderV4, containsString("aws4_request"));
             }
-            if (region != null && authorizationHeaderV4 != null) {
+            if (authorizationHeaderV4 != null) {
                 assertThat(authorizationHeaderV4, containsString("/" + region + "/s3/"));
             }
         }
@@ -298,7 +303,7 @@ private static class S3ErroneousHttpHandler extends ErroneousHttpHandler {
         @Override
         protected String requestUniqueId(final HttpExchange exchange) {
             // Amazon SDK client provides a unique ID per request
-            return exchange.getRequestHeaders().getFirst(AmazonHttpClient.HEADER_SDK_TRANSACTION_ID);
+            return exchange.getRequestHeaders().getFirst(ApplyTransactionIdStage.HEADER_SDK_TRANSACTION_ID);
         }
     }
 
@@ -314,7 +319,7 @@ private static class S3StatsCollectorHttpHandler extends HttpStatsCollectorHandl
 
         @Override
         public void maybeTrack(final String request, Headers requestHeaders) {
-            if (Regex.simpleMatch("GET /*/?prefix=*", request)) {
+            if (Regex.simpleMatch("GET /*?list-type=*", request)) {
                 trackRequest("ListObjects");
             } else if (Regex.simpleMatch("GET /*/*", request)) {
                 trackRequest("GetObject");
diff --git a/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3RepositoryThirdPartyTests.java b/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3RepositoryThirdPartyTests.java
index bc2839d066092..f7a84864a8569 100644
--- a/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3RepositoryThirdPartyTests.java
+++ b/plugins/repository-s3/src/internalClusterTest/java/org/opensearch/repositories/s3/S3RepositoryThirdPartyTests.java
@@ -31,7 +31,10 @@
 
 package org.opensearch.repositories.s3;
 
+import software.amazon.awssdk.services.s3.model.StorageClass;
+
 import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.settings.MockSecureSettings;
@@ -40,6 +43,7 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.AbstractThirdPartyRepositoryTestCase;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.junit.Before;
 
 import java.util.Collection;
 import java.util.Map;
@@ -52,6 +56,21 @@
 
 public class S3RepositoryThirdPartyTests extends AbstractThirdPartyRepositoryTestCase {
 
+    @Override
+    @Before
+    @SuppressForbidden(reason = "Need to set system property here for AWS SDK v2")
+    public void setUp() throws Exception {
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", "config"));
+        super.setUp();
+    }
+
+    @Override
+    @SuppressForbidden(reason = "Need to reset system property here for AWS SDK v2")
+    public void tearDown() throws Exception {
+        SocketAccess.doPrivileged(() -> System.clearProperty("opensearch.path.conf"));
+        super.tearDown();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> getPlugins() {
         return pluginList(S3RepositoryPlugin.class);
@@ -73,6 +92,7 @@ protected SecureSettings credentials() {
     protected void createRepository(String repoName) {
         Settings.Builder settings = Settings.builder()
             .put("bucket", System.getProperty("test.s3.bucket"))
+            .put("region", System.getProperty("test.s3.region", "us-west-2"))
             .put("base_path", System.getProperty("test.s3.base", "testpath"));
         final String endpoint = System.getProperty("test.s3.endpoint");
         if (endpoint != null) {
@@ -81,12 +101,12 @@ protected void createRepository(String repoName) {
             // only test different storage classes when running against the default endpoint, i.e. a genuine S3 service
             if (randomBoolean()) {
                 final String storageClass = randomFrom(
-                    "standard",
-                    "reduced_redundancy",
-                    "standard_ia",
-                    "onezone_ia",
-                    "intelligent_tiering"
-                );
+                    StorageClass.STANDARD,
+                    StorageClass.REDUCED_REDUNDANCY,
+                    StorageClass.STANDARD_IA,
+                    StorageClass.ONEZONE_IA,
+                    StorageClass.INTELLIGENT_TIERING
+                ).toString();
                 logger.info("--> using storage_class [{}]", storageClass);
                 settings.put("storage_class", storageClass);
             }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3Reference.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3Reference.java
new file mode 100644
index 0000000000000..0b5fcb6df280e
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3Reference.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.concurrent.RefCountedReleasable;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+/**
+ * Handles the shutdown of the wrapped {@link software.amazon.awssdk.services.s3.S3AsyncClient} using reference
+ * counting.
+ */
+public class AmazonAsyncS3Reference extends RefCountedReleasable<AmazonAsyncS3WithCredentials> {
+
+    private static final Logger logger = LogManager.getLogger(AmazonAsyncS3Reference.class);
+
+    AmazonAsyncS3Reference(AmazonAsyncS3WithCredentials client) {
+        super("AWS_S3_CLIENT", client, () -> {
+            client.client().close();
+            client.priorityClient().close();
+            AwsCredentialsProvider credentials = client.credentials();
+            if (credentials instanceof Closeable) {
+                try {
+                    ((Closeable) credentials).close();
+                } catch (IOException e) {
+                    logger.error("Exception while closing AwsCredentialsProvider", e);
+                }
+            }
+        });
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3WithCredentials.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3WithCredentials.java
new file mode 100644
index 0000000000000..fa2db83729d25
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonAsyncS3WithCredentials.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+
+import org.opensearch.common.Nullable;
+
+/**
+ * The holder of the AmazonS3 and AWSCredentialsProvider
+ */
+final class AmazonAsyncS3WithCredentials {
+    private final S3AsyncClient client;
+    private final S3AsyncClient priorityClient;
+    private final AwsCredentialsProvider credentials;
+
+    private AmazonAsyncS3WithCredentials(
+        final S3AsyncClient client,
+        final S3AsyncClient priorityClient,
+        @Nullable final AwsCredentialsProvider credentials
+    ) {
+        this.client = client;
+        this.credentials = credentials;
+        this.priorityClient = priorityClient;
+    }
+
+    S3AsyncClient client() {
+        return client;
+    }
+
+    S3AsyncClient priorityClient() {
+        return priorityClient;
+    }
+
+    AwsCredentialsProvider credentials() {
+        return credentials;
+    }
+
+    static AmazonAsyncS3WithCredentials create(
+        final S3AsyncClient client,
+        final S3AsyncClient priorityClient,
+        @Nullable final AwsCredentialsProvider credentials
+    ) {
+        return new AmazonAsyncS3WithCredentials(client, priorityClient, credentials);
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3Reference.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3Reference.java
index 62e415705a011..21554147d6f7c 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3Reference.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3Reference.java
@@ -32,17 +32,35 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.s3.AmazonS3Client;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.services.s3.S3Client;
+
+import org.opensearch.common.Nullable;
 import org.opensearch.common.concurrent.RefCountedReleasable;
 
 /**
- * Handles the shutdown of the wrapped {@link AmazonS3Client} using reference
+ * Handles the shutdown of the wrapped {@link S3Client} using reference
  * counting.
  */
-public class AmazonS3Reference extends RefCountedReleasable<AmazonS3> {
+public class AmazonS3Reference extends RefCountedReleasable<S3Client> {
+    AmazonS3Reference(S3Client client) {
+        this(client, null);
+    }
+
+    AmazonS3Reference(AmazonS3WithCredentials client) {
+        this(client.client(), client.credentials());
+    }
 
-    AmazonS3Reference(AmazonS3 client) {
-        super("AWS_S3_CLIENT", client, client::shutdown);
+    AmazonS3Reference(S3Client client, @Nullable AwsCredentialsProvider credentials) {
+        super("AWS_S3_CLIENT", client, () -> {
+            client.close();
+            if (credentials instanceof AutoCloseable) {
+                try {
+                    ((AutoCloseable) credentials).close();
+                } catch (Exception e) {
+                    /* Do nothing here */
+                }
+            }
+        });
     }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3WithCredentials.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3WithCredentials.java
new file mode 100644
index 0000000000000..5e7459d532779
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3WithCredentials.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.services.s3.S3Client;
+
+import org.opensearch.common.Nullable;
+
+/**
+ * The holder of the AmazonS3 and AwsCredentialsProvider
+ */
+final class AmazonS3WithCredentials {
+    private final S3Client client;
+    private final AwsCredentialsProvider credentials;
+
+    private AmazonS3WithCredentials(final S3Client client, @Nullable final AwsCredentialsProvider credentials) {
+        this.client = client;
+        this.credentials = credentials;
+    }
+
+    S3Client client() {
+        return client;
+    }
+
+    AwsCredentialsProvider credentials() {
+        return credentials;
+    }
+
+    static AmazonS3WithCredentials create(final S3Client client, @Nullable final AwsCredentialsProvider credentials) {
+        return new AmazonS3WithCredentials(client, credentials);
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/ProxySettings.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/ProxySettings.java
index 430af0096d8b5..94327872bdd72 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/ProxySettings.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/ProxySettings.java
@@ -8,9 +8,11 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.Protocol;
-import org.opensearch.common.Strings;
+import software.amazon.awssdk.core.exception.SdkException;
+
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.repositories.s3.utils.Protocol;
 
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
@@ -28,7 +30,7 @@ public static enum ProxyType {
 
         private final String name;
 
-        private ProxyType(String name) {
+        ProxyType(String name) {
             this.name = name;
         }
 
@@ -84,7 +86,7 @@ public InetSocketAddress getAddress() {
             return new InetSocketAddress(InetAddress.getByName(host), port);
         } catch (UnknownHostException e) {
             // this error won't be thrown since validation of the host name is in the S3ClientSettings
-            throw new RuntimeException(e);
+            throw SdkException.create("Unknown host", e);
         }
     }
 
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3AsyncService.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3AsyncService.java
new file mode 100644
index 0000000000000..08215ebdd45e0
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3AsyncService.java
@@ -0,0 +1,431 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.ContainerCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.InstanceProfileCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.SdkSystemSetting;
+import software.amazon.awssdk.core.client.config.ClientAsyncConfiguration;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.client.config.SdkAdvancedAsyncClientOption;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.core.retry.backoff.BackoffStrategy;
+import software.amazon.awssdk.http.async.SdkAsyncHttpClient;
+import software.amazon.awssdk.http.nio.netty.NettyNioAsyncHttpClient;
+import software.amazon.awssdk.http.nio.netty.ProxyConfiguration;
+import software.amazon.awssdk.http.nio.netty.SdkEventLoopGroup;
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.S3AsyncClientBuilder;
+import software.amazon.awssdk.services.sts.StsClient;
+import software.amazon.awssdk.services.sts.StsClientBuilder;
+import software.amazon.awssdk.services.sts.auth.StsAssumeRoleCredentialsProvider;
+import software.amazon.awssdk.services.sts.auth.StsWebIdentityTokenFileCredentialsProvider;
+import software.amazon.awssdk.services.sts.model.AssumeRoleRequest;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.repositories.s3.S3ClientSettings.IrsaCredentials;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferEventLoopGroup;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.URI;
+import java.nio.file.Path;
+import java.time.Duration;
+import java.util.Map;
+
+import static java.util.Collections.emptyMap;
+
+class S3AsyncService implements Closeable {
+    private static final Logger logger = LogManager.getLogger(S3AsyncService.class);
+
+    private static final String STS_ENDPOINT_OVERRIDE_SYSTEM_PROPERTY = "aws.stsEndpointOverride";
+
+    private static final String DEFAULT_S3_ENDPOINT = "s3.amazonaws.com";
+
+    private volatile Map<S3ClientSettings, AmazonAsyncS3Reference> clientsCache = emptyMap();
+
+    /**
+     * Client settings calculated from static configuration and settings in the keystore.
+     */
+    private volatile Map<String, S3ClientSettings> staticClientSettings;
+
+    /**
+     * Client settings derived from those in {@link #staticClientSettings} by combining them with settings
+     * in the {@link RepositoryMetadata}.
+     */
+    private volatile Map<Settings, S3ClientSettings> derivedClientSettings = emptyMap();
+
+    S3AsyncService(final Path configPath) {
+        staticClientSettings = MapBuilder.<String, S3ClientSettings>newMapBuilder()
+            .put("default", S3ClientSettings.getClientSettings(Settings.EMPTY, "default", configPath))
+            .immutableMap();
+    }
+
+    /**
+     * Refreshes the settings for the AmazonS3 clients and clears the cache of
+     * existing clients. New clients will be build using these new settings. Old
+     * clients are usable until released. On release they will be destroyed instead
+     * of being returned to the cache.
+     */
+    public synchronized void refreshAndClearCache(Map<String, S3ClientSettings> clientsSettings) {
+        // shutdown all unused clients
+        // others will shutdown on their respective release
+        releaseCachedClients();
+        this.staticClientSettings = MapBuilder.newMapBuilder(clientsSettings).immutableMap();
+        derivedClientSettings = emptyMap();
+        assert this.staticClientSettings.containsKey("default") : "always at least have 'default'";
+        // clients are built lazily by {@link client}
+    }
+
+    /**
+     * Attempts to retrieve a client by its repository metadata and settings from the cache.
+     * If the client does not exist it will be created.
+     */
+    public AmazonAsyncS3Reference client(
+        RepositoryMetadata repositoryMetadata,
+        AsyncExecutorContainer priorityExecutorBuilder,
+        AsyncExecutorContainer normalExecutorBuilder
+    ) {
+        final S3ClientSettings clientSettings = settings(repositoryMetadata);
+        {
+            final AmazonAsyncS3Reference clientReference = clientsCache.get(clientSettings);
+            if (clientReference != null && clientReference.tryIncRef()) {
+                return clientReference;
+            }
+        }
+        synchronized (this) {
+            final AmazonAsyncS3Reference existing = clientsCache.get(clientSettings);
+            if (existing != null && existing.tryIncRef()) {
+                return existing;
+            }
+            final AmazonAsyncS3Reference clientReference = new AmazonAsyncS3Reference(
+                buildClient(clientSettings, priorityExecutorBuilder, normalExecutorBuilder)
+            );
+            clientReference.incRef();
+            clientsCache = MapBuilder.newMapBuilder(clientsCache).put(clientSettings, clientReference).immutableMap();
+            return clientReference;
+        }
+    }
+
+    /**
+     * Either fetches {@link S3ClientSettings} for a given {@link RepositoryMetadata} from cached settings or creates them
+     * by overriding static client settings from {@link #staticClientSettings} with settings found in the repository metadata.
+     * @param repositoryMetadata Repository Metadata
+     * @return S3ClientSettings
+     */
+    S3ClientSettings settings(RepositoryMetadata repositoryMetadata) {
+        final Settings settings = repositoryMetadata.settings();
+        {
+            final S3ClientSettings existing = derivedClientSettings.get(settings);
+            if (existing != null) {
+                return existing;
+            }
+        }
+        final String clientName = S3Repository.CLIENT_NAME.get(settings);
+        final S3ClientSettings staticSettings = staticClientSettings.get(clientName);
+        if (staticSettings != null) {
+            synchronized (this) {
+                final S3ClientSettings existing = derivedClientSettings.get(settings);
+                if (existing != null) {
+                    return existing;
+                }
+                final S3ClientSettings newSettings = staticSettings.refine(settings);
+                derivedClientSettings = MapBuilder.newMapBuilder(derivedClientSettings).put(settings, newSettings).immutableMap();
+                return newSettings;
+            }
+        }
+        throw new IllegalArgumentException(
+            "Unknown s3 client name ["
+                + clientName
+                + "]. Existing client configs: "
+                + Strings.collectionToDelimitedString(staticClientSettings.keySet(), ",")
+        );
+    }
+
+    // proxy for testing
+    synchronized AmazonAsyncS3WithCredentials buildClient(
+        final S3ClientSettings clientSettings,
+        AsyncExecutorContainer priorityExecutorBuilder,
+        AsyncExecutorContainer normalExecutorBuilder
+    ) {
+        setDefaultAwsProfilePath();
+        final S3AsyncClientBuilder builder = S3AsyncClient.builder();
+        builder.overrideConfiguration(buildOverrideConfiguration(clientSettings));
+        final AwsCredentialsProvider credentials = buildCredentials(logger, clientSettings);
+        builder.credentialsProvider(credentials);
+
+        String endpoint = Strings.hasLength(clientSettings.endpoint) ? clientSettings.endpoint : DEFAULT_S3_ENDPOINT;
+        if ((endpoint.startsWith("http://") || endpoint.startsWith("https://")) == false) {
+            // Manually add the schema to the endpoint to work around https://github.com/aws/aws-sdk-java/issues/2274
+            endpoint = clientSettings.protocol.toString() + "://" + endpoint;
+        }
+        logger.debug("using endpoint [{}] and region [{}]", endpoint, clientSettings.region);
+
+        // If the endpoint configuration isn't set on the builder then the default behaviour is to try
+        // and work out what region we are in and use an appropriate endpoint - see AwsClientBuilder#setRegion.
+        // In contrast, directly-constructed clients use s3.amazonaws.com unless otherwise instructed. We currently
+        // use a directly-constructed client, and need to keep the existing behaviour to avoid a breaking change,
+        // so to move to using the builder we must set it explicitly to keep the existing behaviour.
+        //
+        // We do this because directly constructing the client is deprecated (was already deprecated in 1.1.223 too)
+        // so this change removes that usage of a deprecated API.
+        builder.endpointOverride(URI.create(endpoint));
+        builder.region(Region.of(clientSettings.region));
+        if (clientSettings.pathStyleAccess) {
+            builder.forcePathStyle(true);
+        }
+
+        builder.httpClient(buildHttpClient(clientSettings, priorityExecutorBuilder.getAsyncTransferEventLoopGroup()));
+        builder.asyncConfiguration(
+            ClientAsyncConfiguration.builder()
+                .advancedOption(
+                    SdkAdvancedAsyncClientOption.FUTURE_COMPLETION_EXECUTOR,
+                    priorityExecutorBuilder.getFutureCompletionExecutor()
+                )
+                .build()
+        );
+        final S3AsyncClient priorityClient = SocketAccess.doPrivileged(builder::build);
+
+        builder.httpClient(buildHttpClient(clientSettings, normalExecutorBuilder.getAsyncTransferEventLoopGroup()));
+        builder.asyncConfiguration(
+            ClientAsyncConfiguration.builder()
+                .advancedOption(
+                    SdkAdvancedAsyncClientOption.FUTURE_COMPLETION_EXECUTOR,
+                    normalExecutorBuilder.getFutureCompletionExecutor()
+                )
+                .build()
+        );
+        final S3AsyncClient client = SocketAccess.doPrivileged(builder::build);
+
+        return AmazonAsyncS3WithCredentials.create(client, priorityClient, credentials);
+    }
+
+    static ClientOverrideConfiguration buildOverrideConfiguration(final S3ClientSettings clientSettings) {
+        return ClientOverrideConfiguration.builder()
+            .retryPolicy(
+                RetryPolicy.builder()
+                    .numRetries(clientSettings.maxRetries)
+                    .throttlingBackoffStrategy(
+                        clientSettings.throttleRetries ? BackoffStrategy.defaultThrottlingStrategy() : BackoffStrategy.none()
+                    )
+                    .build()
+            )
+            .apiCallAttemptTimeout(Duration.ofMillis(clientSettings.requestTimeoutMillis))
+            .build();
+    }
+
+    // pkg private for tests
+    static SdkAsyncHttpClient buildHttpClient(S3ClientSettings clientSettings, AsyncTransferEventLoopGroup asyncTransferEventLoopGroup) {
+        // the response metadata cache is only there for diagnostics purposes,
+        // but can force objects from every response to the old generation.
+        NettyNioAsyncHttpClient.Builder clientBuilder = NettyNioAsyncHttpClient.builder();
+
+        if (clientSettings.proxySettings.getType() != ProxySettings.ProxyType.DIRECT) {
+            ProxyConfiguration.Builder proxyConfiguration = ProxyConfiguration.builder();
+            proxyConfiguration.scheme(clientSettings.proxySettings.getType().toProtocol().toString());
+            proxyConfiguration.host(clientSettings.proxySettings.getHostName());
+            proxyConfiguration.port(clientSettings.proxySettings.getPort());
+            proxyConfiguration.username(clientSettings.proxySettings.getUsername());
+            proxyConfiguration.password(clientSettings.proxySettings.getPassword());
+            clientBuilder.proxyConfiguration(proxyConfiguration.build());
+        }
+
+        // TODO: add max retry and UseThrottleRetry. Replace values with settings and put these in default settings
+        clientBuilder.connectionTimeout(Duration.ofMillis(clientSettings.connectionTimeoutMillis));
+        clientBuilder.connectionAcquisitionTimeout(Duration.ofMillis(clientSettings.connectionAcquisitionTimeoutMillis));
+        clientBuilder.maxPendingConnectionAcquires(10_000);
+        clientBuilder.maxConcurrency(clientSettings.maxConnections);
+        clientBuilder.eventLoopGroup(SdkEventLoopGroup.create(asyncTransferEventLoopGroup.getEventLoopGroup()));
+        clientBuilder.tcpKeepAlive(true);
+
+        return clientBuilder.build();
+    }
+
+    // pkg private for tests
+    static AwsCredentialsProvider buildCredentials(Logger logger, S3ClientSettings clientSettings) {
+        final AwsCredentials basicCredentials = clientSettings.credentials;
+        final IrsaCredentials irsaCredentials = buildFromEnvironment(clientSettings.irsaCredentials);
+
+        // If IAM Roles for Service Accounts (IRSA) credentials are configured, start with them first
+        if (irsaCredentials != null) {
+            logger.debug("Using IRSA credentials");
+
+            final Region region = Region.of(clientSettings.region);
+            StsClient stsClient = SocketAccess.doPrivileged(() -> {
+                StsClientBuilder builder = StsClient.builder().region(region);
+
+                final String stsEndpoint = System.getProperty(STS_ENDPOINT_OVERRIDE_SYSTEM_PROPERTY);
+                if (stsEndpoint != null) {
+                    builder = builder.endpointOverride(URI.create(stsEndpoint));
+                }
+
+                if (basicCredentials != null) {
+                    builder = builder.credentialsProvider(StaticCredentialsProvider.create(basicCredentials));
+                } else {
+                    builder = builder.credentialsProvider(DefaultCredentialsProvider.create());
+                }
+
+                return builder.build();
+            });
+
+            if (irsaCredentials.getIdentityTokenFile() == null) {
+                final StsAssumeRoleCredentialsProvider.Builder stsCredentialsProviderBuilder = StsAssumeRoleCredentialsProvider.builder()
+                    .stsClient(stsClient)
+                    .refreshRequest(
+                        AssumeRoleRequest.builder()
+                            .roleArn(irsaCredentials.getRoleArn())
+                            .roleSessionName(irsaCredentials.getRoleSessionName())
+                            .build()
+                    );
+
+                final StsAssumeRoleCredentialsProvider stsCredentialsProvider = SocketAccess.doPrivileged(
+                    stsCredentialsProviderBuilder::build
+                );
+
+                return new PrivilegedSTSAssumeRoleSessionCredentialsProvider<>(stsClient, stsCredentialsProvider);
+            } else {
+                final StsWebIdentityTokenFileCredentialsProvider.Builder stsCredentialsProviderBuilder =
+                    StsWebIdentityTokenFileCredentialsProvider.builder()
+                        .stsClient(stsClient)
+                        .roleArn(irsaCredentials.getRoleArn())
+                        .roleSessionName(irsaCredentials.getRoleSessionName())
+                        .webIdentityTokenFile(Path.of(irsaCredentials.getIdentityTokenFile()));
+
+                final StsWebIdentityTokenFileCredentialsProvider stsCredentialsProvider = SocketAccess.doPrivileged(
+                    stsCredentialsProviderBuilder::build
+                );
+
+                return new PrivilegedSTSAssumeRoleSessionCredentialsProvider<>(stsClient, stsCredentialsProvider);
+            }
+        } else if (basicCredentials != null) {
+            logger.debug("Using basic key/secret credentials");
+            return StaticCredentialsProvider.create(basicCredentials);
+        } else {
+            logger.debug("Using instance profile credentials");
+            return new PrivilegedInstanceProfileCredentialsProvider();
+        }
+    }
+
+    // Aws v2 sdk tries to load a default profile from home path which is restricted. Hence, setting these to random
+    // valid paths.
+    @SuppressForbidden(reason = "Need to provide this override to v2 SDK so that path does not default to home path")
+    private static void setDefaultAwsProfilePath() {
+        if (ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.getStringValue().isEmpty()) {
+            System.setProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+        if (ProfileFileSystemSetting.AWS_CONFIG_FILE.getStringValue().isEmpty()) {
+            System.setProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), System.getProperty("opensearch.path.conf"));
+        }
+    }
+
+    private static IrsaCredentials buildFromEnvironment(IrsaCredentials defaults) {
+        if (defaults == null) {
+            return null;
+        }
+
+        String webIdentityTokenFile = defaults.getIdentityTokenFile();
+        if (webIdentityTokenFile == null) {
+            webIdentityTokenFile = System.getenv(SdkSystemSetting.AWS_WEB_IDENTITY_TOKEN_FILE.environmentVariable());
+        }
+
+        String roleArn = defaults.getRoleArn();
+        if (roleArn == null) {
+            roleArn = System.getenv(SdkSystemSetting.AWS_ROLE_ARN.environmentVariable());
+        }
+
+        String roleSessionName = defaults.getRoleSessionName();
+        if (roleSessionName == null) {
+            roleSessionName = System.getenv(SdkSystemSetting.AWS_ROLE_SESSION_NAME.environmentVariable());
+        }
+
+        return new IrsaCredentials(webIdentityTokenFile, roleArn, roleSessionName);
+    }
+
+    private synchronized void releaseCachedClients() {
+        // the clients will shutdown when they will not be used anymore
+        for (final AmazonAsyncS3Reference clientReference : clientsCache.values()) {
+            clientReference.decRef();
+        }
+
+        // clear previously cached clients, they will be build lazily
+        clientsCache = emptyMap();
+        derivedClientSettings = emptyMap();
+    }
+
+    static class PrivilegedInstanceProfileCredentialsProvider implements AwsCredentialsProvider {
+        private final AwsCredentialsProvider credentials;
+
+        private PrivilegedInstanceProfileCredentialsProvider() {
+            this.credentials = initializeProvider();
+        }
+
+        private AwsCredentialsProvider initializeProvider() {
+            if (SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI.getStringValue().isPresent()
+                || SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_FULL_URI.getStringValue().isPresent()) {
+
+                return ContainerCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
+            }
+            // InstanceProfileCredentialsProvider as last item of chain
+            return InstanceProfileCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
+        }
+
+        @Override
+        public AwsCredentials resolveCredentials() {
+            return SocketAccess.doPrivileged(credentials::resolveCredentials);
+        }
+    }
+
+    static class PrivilegedSTSAssumeRoleSessionCredentialsProvider<P extends AwsCredentialsProvider & AutoCloseable>
+        implements
+            AwsCredentialsProvider,
+            Closeable {
+        private final P credentials;
+        private final StsClient stsClient;
+
+        private PrivilegedSTSAssumeRoleSessionCredentialsProvider(@Nullable final StsClient stsClient, final P credentials) {
+            this.stsClient = stsClient;
+            this.credentials = credentials;
+        }
+
+        @Override
+        public void close() throws IOException {
+            SocketAccess.doPrivilegedIOException(() -> {
+                credentials.close();
+                if (stsClient != null) {
+                    stsClient.close();
+                }
+                return null;
+            });
+        }
+
+        @Override
+        public AwsCredentials resolveCredentials() {
+            return SocketAccess.doPrivileged(credentials::resolveCredentials);
+        }
+    }
+
+    @Override
+    public void close() {
+        releaseCachedClients();
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicCredentials.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicCredentials.java
deleted file mode 100644
index 5f00236c671eb..0000000000000
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicCredentials.java
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.repositories.s3;
-
-import com.amazonaws.auth.AWSCredentials;
-
-import java.util.Objects;
-
-class S3BasicCredentials implements AWSCredentials {
-
-    private final String accessKey;
-
-    private final String secretKey;
-
-    S3BasicCredentials(String accessKey, String secretKey) {
-        this.accessKey = accessKey;
-        this.secretKey = secretKey;
-    }
-
-    @Override
-    public final String getAWSAccessKeyId() {
-        return accessKey;
-    }
-
-    @Override
-    public final String getAWSSecretKey() {
-        return secretKey;
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass()) {
-            return false;
-        }
-        final S3BasicCredentials that = (S3BasicCredentials) o;
-        return accessKey.equals(that.accessKey) && secretKey.equals(that.secretKey);
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hash(accessKey, secretKey);
-    }
-}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicSessionCredentials.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicSessionCredentials.java
deleted file mode 100644
index 2264dd6cde297..0000000000000
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BasicSessionCredentials.java
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.repositories.s3;
-
-import com.amazonaws.auth.AWSSessionCredentials;
-
-import java.util.Objects;
-
-final class S3BasicSessionCredentials extends S3BasicCredentials implements AWSSessionCredentials {
-
-    private final String sessionToken;
-
-    S3BasicSessionCredentials(String accessKey, String secretKey, String sessionToken) {
-        super(accessKey, secretKey);
-        this.sessionToken = sessionToken;
-    }
-
-    @Override
-    public String getSessionToken() {
-        return sessionToken;
-    }
-
-    @Override
-    public boolean equals(final Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass()) {
-            return false;
-        }
-        final S3BasicSessionCredentials that = (S3BasicSessionCredentials) o;
-        return sessionToken.equals(that.sessionToken)
-            && getAWSAccessKeyId().equals(that.getAWSAccessKeyId())
-            && getAWSSecretKey().equals(that.getAWSSecretKey());
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hash(sessionToken, getAWSAccessKeyId(), getAWSSecretKey());
-    }
-}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
index 678be7c6f13f2..fcfccf50ad326 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
@@ -32,45 +32,75 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.services.s3.model.AbortMultipartUploadRequest;
-import com.amazonaws.services.s3.model.CompleteMultipartUploadRequest;
-import com.amazonaws.services.s3.model.DeleteObjectsRequest;
-import com.amazonaws.services.s3.model.InitiateMultipartUploadRequest;
-import com.amazonaws.services.s3.model.ListObjectsRequest;
-import com.amazonaws.services.s3.model.MultiObjectDeleteException;
-import com.amazonaws.services.s3.model.ObjectListing;
-import com.amazonaws.services.s3.model.ObjectMetadata;
-import com.amazonaws.services.s3.model.PartETag;
-import com.amazonaws.services.s3.model.PutObjectRequest;
-import com.amazonaws.services.s3.model.UploadPartRequest;
-import com.amazonaws.services.s3.model.UploadPartResult;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.core.async.AsyncResponseTransformer;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.sync.RequestBody;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CommonPrefix;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
+import software.amazon.awssdk.services.s3.model.CompletedPart;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.Delete;
+import software.amazon.awssdk.services.s3.model.DeleteObjectsRequest;
+import software.amazon.awssdk.services.s3.model.DeleteObjectsResponse;
+import software.amazon.awssdk.services.s3.model.GetObjectAttributesRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectAttributesResponse;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.HeadObjectRequest;
+import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
+import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
+import software.amazon.awssdk.services.s3.model.ObjectAttributes;
+import software.amazon.awssdk.services.s3.model.ObjectIdentifier;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.S3Error;
+import software.amazon.awssdk.services.s3.model.ServerSideEncryption;
+import software.amazon.awssdk.services.s3.model.UploadPartRequest;
+import software.amazon.awssdk.services.s3.model.UploadPartResponse;
+import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStoreException;
 import org.opensearch.common.blobstore.DeleteResult;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
 import org.opensearch.common.blobstore.support.AbstractBlobContainer;
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.repositories.s3.async.UploadRequest;
+import org.opensearch.repositories.s3.utils.HttpRangeUtils;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -79,12 +109,13 @@
 import static org.opensearch.repositories.s3.S3Repository.MAX_FILE_SIZE_USING_MULTIPART;
 import static org.opensearch.repositories.s3.S3Repository.MIN_PART_SIZE_USING_MULTIPART;
 
-class S3BlobContainer extends AbstractBlobContainer {
+class S3BlobContainer extends AbstractBlobContainer implements AsyncMultiStreamBlobContainer {
 
     private static final Logger logger = LogManager.getLogger(S3BlobContainer.class);
 
     /**
      * Maximum number of deletes in a {@link DeleteObjectsRequest}.
+     *
      * @see <a href="https://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html">S3 Documentation</a>.
      */
     private static final int MAX_BULK_DELETES = 1000;
@@ -101,7 +132,13 @@ class S3BlobContainer extends AbstractBlobContainer {
     @Override
     public boolean blobExists(String blobName) {
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            return SocketAccess.doPrivileged(() -> clientReference.get().doesObjectExist(blobStore.bucket(), buildKey(blobName)));
+            SocketAccess.doPrivileged(
+                () -> clientReference.get()
+                    .headObject(HeadObjectRequest.builder().bucket(blobStore.bucket()).key(buildKey(blobName)).build())
+            );
+            return true;
+        } catch (NoSuchKeyException e) {
+            return false;
         } catch (final Exception e) {
             throw new BlobStoreException("Failed to check if blob [" + blobName + "] exists", e);
         }
@@ -149,6 +186,88 @@ public void writeBlob(String blobName, InputStream inputStream, long blobSize, b
         });
     }
 
+    @Override
+    public void asyncBlobUpload(WriteContext writeContext, ActionListener<Void> completionListener) throws IOException {
+        UploadRequest uploadRequest = new UploadRequest(
+            blobStore.bucket(),
+            buildKey(writeContext.getFileName()),
+            writeContext.getFileSize(),
+            writeContext.getWritePriority(),
+            writeContext.getUploadFinalizer(),
+            writeContext.doRemoteDataIntegrityCheck(),
+            writeContext.getExpectedChecksum()
+        );
+        try {
+            long partSize = blobStore.getAsyncTransferManager().calculateOptimalPartSize(writeContext.getFileSize());
+            StreamContext streamContext = SocketAccess.doPrivileged(() -> writeContext.getStreamProvider(partSize));
+            try (AmazonAsyncS3Reference amazonS3Reference = SocketAccess.doPrivileged(blobStore::asyncClientReference)) {
+
+                S3AsyncClient s3AsyncClient = writeContext.getWritePriority() == WritePriority.HIGH
+                    ? amazonS3Reference.get().priorityClient()
+                    : amazonS3Reference.get().client();
+                CompletableFuture<Void> completableFuture = blobStore.getAsyncTransferManager()
+                    .uploadObject(s3AsyncClient, uploadRequest, streamContext);
+                completableFuture.whenComplete((response, throwable) -> {
+                    if (throwable == null) {
+                        completionListener.onResponse(response);
+                    } else {
+                        Exception ex = throwable instanceof Error ? new Exception(throwable) : (Exception) throwable;
+                        completionListener.onFailure(ex);
+                    }
+                });
+            }
+        } catch (Exception e) {
+            logger.info("exception error from blob container for file {}", writeContext.getFileName());
+            throw new IOException(e);
+        }
+    }
+
+    @ExperimentalApi
+    @Override
+    public void readBlobAsync(String blobName, ActionListener<ReadContext> listener) {
+        try (AmazonAsyncS3Reference amazonS3Reference = SocketAccess.doPrivileged(blobStore::asyncClientReference)) {
+            final S3AsyncClient s3AsyncClient = amazonS3Reference.get().client();
+            final String bucketName = blobStore.bucket();
+            final String blobKey = buildKey(blobName);
+
+            final CompletableFuture<GetObjectAttributesResponse> blobMetadataFuture = getBlobMetadata(s3AsyncClient, bucketName, blobKey);
+
+            blobMetadataFuture.whenComplete((blobMetadata, throwable) -> {
+                if (throwable != null) {
+                    Exception ex = throwable.getCause() instanceof Exception
+                        ? (Exception) throwable.getCause()
+                        : new Exception(throwable.getCause());
+                    listener.onFailure(ex);
+                    return;
+                }
+
+                final List<ReadContext.StreamPartCreator> blobPartInputStreamFutures = new ArrayList<>();
+                final long blobSize = blobMetadata.objectSize();
+                final Integer numberOfParts = blobMetadata.objectParts() == null ? null : blobMetadata.objectParts().totalPartsCount();
+                final String blobChecksum = blobMetadata.checksum().checksumCRC32();
+
+                if (numberOfParts == null) {
+                    blobPartInputStreamFutures.add(() -> getBlobPartInputStreamContainer(s3AsyncClient, bucketName, blobKey, null));
+                } else {
+                    // S3 multipart files use 1 to n indexing
+                    for (int partNumber = 1; partNumber <= numberOfParts; partNumber++) {
+                        final int innerPartNumber = partNumber;
+                        blobPartInputStreamFutures.add(
+                            () -> getBlobPartInputStreamContainer(s3AsyncClient, bucketName, blobKey, innerPartNumber)
+                        );
+                    }
+                }
+                listener.onResponse(new ReadContext(blobSize, blobPartInputStreamFutures, blobChecksum));
+            });
+        } catch (Exception ex) {
+            listener.onFailure(SdkException.create("Error occurred while fetching blob parts from the repository", ex));
+        }
+    }
+
+    public boolean remoteIntegrityCheckSupported() {
+        return true;
+    }
+
     // package private for testing
     long getLargeBlobThresholdInBytes() {
         return blobStore.bufferSizeInBytes();
@@ -164,38 +283,39 @@ public DeleteResult delete() throws IOException {
         final AtomicLong deletedBlobs = new AtomicLong();
         final AtomicLong deletedBytes = new AtomicLong();
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            ObjectListing prevListing = null;
-            while (true) {
-                ObjectListing list;
-                if (prevListing != null) {
-                    final ObjectListing finalPrevListing = prevListing;
-                    list = SocketAccess.doPrivileged(() -> clientReference.get().listNextBatchOfObjects(finalPrevListing));
-                } else {
-                    final ListObjectsRequest listObjectsRequest = new ListObjectsRequest();
-                    listObjectsRequest.setBucketName(blobStore.bucket());
-                    listObjectsRequest.setPrefix(keyPath);
-                    listObjectsRequest.setRequestMetricCollector(blobStore.listMetricCollector);
-                    list = SocketAccess.doPrivileged(() -> clientReference.get().listObjects(listObjectsRequest));
-                }
-                final List<String> blobsToDelete = new ArrayList<>();
-                list.getObjectSummaries().forEach(s3ObjectSummary -> {
+            ListObjectsV2Iterable listObjectsIterable = SocketAccess.doPrivileged(
+                () -> clientReference.get()
+                    .listObjectsV2Paginator(
+                        ListObjectsV2Request.builder()
+                            .bucket(blobStore.bucket())
+                            .prefix(keyPath)
+                            .overrideConfiguration(
+                                o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().listObjectsMetricPublisher)
+                            )
+                            .build()
+                    )
+            );
+
+            Iterator<ListObjectsV2Response> listObjectsResponseIterator = listObjectsIterable.iterator();
+            while (listObjectsResponseIterator.hasNext()) {
+                ListObjectsV2Response listObjectsResponse = SocketAccess.doPrivileged(listObjectsResponseIterator::next);
+                List<String> blobsToDelete = listObjectsResponse.contents().stream().map(s3Object -> {
                     deletedBlobs.incrementAndGet();
-                    deletedBytes.addAndGet(s3ObjectSummary.getSize());
-                    blobsToDelete.add(s3ObjectSummary.getKey());
-                });
-                if (list.isTruncated()) {
-                    doDeleteBlobs(blobsToDelete, false);
-                    prevListing = list;
-                } else {
-                    final List<String> lastBlobsToDelete = new ArrayList<>(blobsToDelete);
-                    lastBlobsToDelete.add(keyPath);
-                    doDeleteBlobs(lastBlobsToDelete, false);
-                    break;
+                    deletedBytes.addAndGet(s3Object.size());
+
+                    return s3Object.key();
+                }).collect(Collectors.toList());
+
+                if (!listObjectsResponseIterator.hasNext()) {
+                    blobsToDelete.add(keyPath);
                 }
+
+                doDeleteBlobs(blobsToDelete, false);
             }
-        } catch (final AmazonClientException e) {
+        } catch (SdkException e) {
             throw new IOException("Exception when deleting blob container [" + keyPath + "]", e);
         }
+
         return new DeleteResult(deletedBlobs.get(), deletedBytes.get());
     }
 
@@ -229,34 +349,29 @@ private void doDeleteBlobs(List<String> blobNames, boolean relative) throws IOEx
                 deleteRequests.add(bulkDelete(blobStore.bucket(), partition));
             }
             SocketAccess.doPrivilegedVoid(() -> {
-                AmazonClientException aex = null;
+                SdkException aex = null;
                 for (DeleteObjectsRequest deleteRequest : deleteRequests) {
-                    List<String> keysInRequest = deleteRequest.getKeys()
+                    List<String> keysInRequest = deleteRequest.delete()
+                        .objects()
                         .stream()
-                        .map(DeleteObjectsRequest.KeyVersion::getKey)
+                        .map(ObjectIdentifier::key)
                         .collect(Collectors.toList());
                     try {
-                        clientReference.get().deleteObjects(deleteRequest);
+                        DeleteObjectsResponse deleteObjectsResponse = clientReference.get().deleteObjects(deleteRequest);
                         outstanding.removeAll(keysInRequest);
-                    } catch (MultiObjectDeleteException e) {
-                        // We are sending quiet mode requests so we can't use the deleted keys entry on the exception and instead
-                        // first remove all keys that were sent in the request and then add back those that ran into an exception.
-                        outstanding.removeAll(keysInRequest);
-                        outstanding.addAll(
-                            e.getErrors().stream().map(MultiObjectDeleteException.DeleteError::getKey).collect(Collectors.toSet())
-                        );
-                        logger.warn(
-                            () -> new ParameterizedMessage(
-                                "Failed to delete some blobs {}",
-                                e.getErrors()
-                                    .stream()
-                                    .map(err -> "[" + err.getKey() + "][" + err.getCode() + "][" + err.getMessage() + "]")
-                                    .collect(Collectors.toList())
-                            ),
-                            e
-                        );
-                        aex = ExceptionsHelper.useOrSuppress(aex, e);
-                    } catch (AmazonClientException e) {
+                        outstanding.addAll(deleteObjectsResponse.errors().stream().map(S3Error::key).collect(Collectors.toSet()));
+                        if (!deleteObjectsResponse.errors().isEmpty()) {
+                            logger.warn(
+                                () -> new ParameterizedMessage(
+                                    "Failed to delete some blobs {}",
+                                    deleteObjectsResponse.errors()
+                                        .stream()
+                                        .map(s3Error -> "[" + s3Error.key() + "][" + s3Error.code() + "][" + s3Error.message() + "]")
+                                        .collect(Collectors.toList())
+                                )
+                            );
+                        }
+                    } catch (SdkException e) {
                         // The AWS client threw any unexpected exception and did not execute the request at all so we do not
                         // remove any keys from the outstanding deletes set.
                         aex = ExceptionsHelper.useOrSuppress(aex, e);
@@ -273,18 +388,52 @@ private void doDeleteBlobs(List<String> blobNames, boolean relative) throws IOEx
     }
 
     private static DeleteObjectsRequest bulkDelete(String bucket, List<String> blobs) {
-        return new DeleteObjectsRequest(bucket).withKeys(blobs.toArray(Strings.EMPTY_ARRAY)).withQuiet(true);
+        return DeleteObjectsRequest.builder()
+            .bucket(bucket)
+            .delete(
+                Delete.builder()
+                    .objects(blobs.stream().map(blob -> ObjectIdentifier.builder().key(blob).build()).collect(Collectors.toList()))
+                    .quiet(true)
+                    .build()
+            )
+            .build();
+    }
+
+    @Override
+    public List<BlobMetadata> listBlobsByPrefixInSortedOrder(String blobNamePrefix, int limit, BlobNameSortOrder blobNameSortOrder)
+        throws IOException {
+        // As AWS S3 returns list of keys in Lexicographic order, we don't have to fetch all the keys in order to sort them
+        // We fetch only keys as per the given limit to optimize the fetch. If provided sort order is not Lexicographic,
+        // we fall-back to default implementation of fetching all the keys and sorting them.
+        if (blobNameSortOrder != BlobNameSortOrder.LEXICOGRAPHIC) {
+            return super.listBlobsByPrefixInSortedOrder(blobNamePrefix, limit, blobNameSortOrder);
+        } else {
+            if (limit < 0) {
+                throw new IllegalArgumentException("limit should not be a negative value");
+            }
+            String prefix = blobNamePrefix == null ? keyPath : buildKey(blobNamePrefix);
+            try (AmazonS3Reference clientReference = blobStore.clientReference()) {
+                List<BlobMetadata> blobs = executeListing(clientReference, listObjectsRequest(prefix, limit), limit).stream()
+                    .flatMap(listing -> listing.contents().stream())
+                    .map(s3Object -> new PlainBlobMetadata(s3Object.key().substring(keyPath.length()), s3Object.size()))
+                    .collect(Collectors.toList());
+                return blobs.subList(0, Math.min(limit, blobs.size()));
+            } catch (final Exception e) {
+                throw new IOException("Exception when listing blobs by prefix [" + prefix + "]", e);
+            }
+        }
     }
 
     @Override
     public Map<String, BlobMetadata> listBlobsByPrefix(@Nullable String blobNamePrefix) throws IOException {
+        String prefix = blobNamePrefix == null ? keyPath : buildKey(blobNamePrefix);
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            return executeListing(clientReference, listObjectsRequest(blobNamePrefix == null ? keyPath : buildKey(blobNamePrefix))).stream()
-                .flatMap(listing -> listing.getObjectSummaries().stream())
-                .map(summary -> new PlainBlobMetadata(summary.getKey().substring(keyPath.length()), summary.getSize()))
+            return executeListing(clientReference, listObjectsRequest(prefix)).stream()
+                .flatMap(listing -> listing.contents().stream())
+                .map(s3Object -> new PlainBlobMetadata(s3Object.key().substring(keyPath.length()), s3Object.size()))
                 .collect(Collectors.toMap(PlainBlobMetadata::name, Function.identity()));
-        } catch (final AmazonClientException e) {
-            throw new IOException("Exception when listing blobs by prefix [" + blobNamePrefix + "]", e);
+        } catch (final SdkException e) {
+            throw new IOException("Exception when listing blobs by prefix [" + prefix + "]", e);
         }
     }
 
@@ -296,53 +445,62 @@ public Map<String, BlobMetadata> listBlobs() throws IOException {
     @Override
     public Map<String, BlobContainer> children() throws IOException {
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            return executeListing(clientReference, listObjectsRequest(keyPath)).stream().flatMap(listing -> {
-                assert listing.getObjectSummaries().stream().noneMatch(s -> {
-                    for (String commonPrefix : listing.getCommonPrefixes()) {
-                        if (s.getKey().substring(keyPath.length()).startsWith(commonPrefix)) {
+            return executeListing(clientReference, listObjectsRequest(keyPath)).stream().flatMap(listObjectsResponse -> {
+                assert listObjectsResponse.contents().stream().noneMatch(s -> {
+                    for (CommonPrefix commonPrefix : listObjectsResponse.commonPrefixes()) {
+                        if (s.key().substring(keyPath.length()).startsWith(commonPrefix.prefix())) {
                             return true;
                         }
                     }
                     return false;
                 }) : "Response contained children for listed common prefixes.";
-                return listing.getCommonPrefixes().stream();
+                return listObjectsResponse.commonPrefixes().stream();
             })
-                .map(prefix -> prefix.substring(keyPath.length()))
+                .map(commonPrefix -> commonPrefix.prefix().substring(keyPath.length()))
                 .filter(name -> name.isEmpty() == false)
                 // Stripping the trailing slash off of the common prefix
                 .map(name -> name.substring(0, name.length() - 1))
                 .collect(Collectors.toMap(Function.identity(), name -> blobStore.blobContainer(path().add(name))));
-        } catch (final AmazonClientException e) {
+        } catch (final SdkException e) {
             throw new IOException("Exception when listing children of [" + path().buildAsString() + ']', e);
         }
     }
 
-    private static List<ObjectListing> executeListing(AmazonS3Reference clientReference, ListObjectsRequest listObjectsRequest) {
-        final List<ObjectListing> results = new ArrayList<>();
-        ObjectListing prevListing = null;
-        while (true) {
-            ObjectListing list;
-            if (prevListing != null) {
-                final ObjectListing finalPrevListing = prevListing;
-                list = SocketAccess.doPrivileged(() -> clientReference.get().listNextBatchOfObjects(finalPrevListing));
-            } else {
-                list = SocketAccess.doPrivileged(() -> clientReference.get().listObjects(listObjectsRequest));
-            }
-            results.add(list);
-            if (list.isTruncated()) {
-                prevListing = list;
-            } else {
-                break;
+    private static List<ListObjectsV2Response> executeListing(AmazonS3Reference clientReference, ListObjectsV2Request listObjectsRequest) {
+        return executeListing(clientReference, listObjectsRequest, -1);
+    }
+
+    private static List<ListObjectsV2Response> executeListing(
+        AmazonS3Reference clientReference,
+        ListObjectsV2Request listObjectsRequest,
+        int limit
+    ) {
+        return SocketAccess.doPrivileged(() -> {
+            final List<ListObjectsV2Response> results = new ArrayList<>();
+            int totalObjects = 0;
+            ListObjectsV2Iterable listObjectsIterable = clientReference.get().listObjectsV2Paginator(listObjectsRequest);
+            for (ListObjectsV2Response listObjectsV2Response : listObjectsIterable) {
+                results.add(listObjectsV2Response);
+                totalObjects += listObjectsV2Response.contents().size();
+                if (limit != -1 && totalObjects > limit) {
+                    break;
+                }
             }
-        }
-        return results;
+            return results;
+        });
+    }
+
+    private ListObjectsV2Request listObjectsRequest(String keyPath) {
+        return ListObjectsV2Request.builder()
+            .bucket(blobStore.bucket())
+            .prefix(keyPath)
+            .delimiter("/")
+            .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().listObjectsMetricPublisher))
+            .build();
     }
 
-    private ListObjectsRequest listObjectsRequest(String keyPath) {
-        return new ListObjectsRequest().withBucketName(blobStore.bucket())
-            .withPrefix(keyPath)
-            .withDelimiter("/")
-            .withRequestMetricCollector(blobStore.listMetricCollector);
+    private ListObjectsV2Request listObjectsRequest(String keyPath, int limit) {
+        return listObjectsRequest(keyPath).toBuilder().maxKeys(Math.min(limit, 1000)).build();
     }
 
     private String buildKey(String blobName) {
@@ -363,19 +521,23 @@ void executeSingleUpload(final S3BlobStore blobStore, final String blobName, fin
             throw new IllegalArgumentException("Upload request size [" + blobSize + "] can't be larger than buffer size");
         }
 
-        final ObjectMetadata md = new ObjectMetadata();
-        md.setContentLength(blobSize);
+        PutObjectRequest.Builder putObjectRequestBuilder = PutObjectRequest.builder()
+            .bucket(blobStore.bucket())
+            .key(blobName)
+            .contentLength(blobSize)
+            .storageClass(blobStore.getStorageClass())
+            .acl(blobStore.getCannedACL())
+            .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().putObjectMetricPublisher));
         if (blobStore.serverSideEncryption()) {
-            md.setSSEAlgorithm(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION);
+            putObjectRequestBuilder.serverSideEncryption(ServerSideEncryption.AES256);
         }
-        final PutObjectRequest putRequest = new PutObjectRequest(blobStore.bucket(), blobName, input, md);
-        putRequest.setStorageClass(blobStore.getStorageClass());
-        putRequest.setCannedAcl(blobStore.getCannedACL());
-        putRequest.setRequestMetricCollector(blobStore.putMetricCollector);
 
+        PutObjectRequest putObjectRequest = putObjectRequestBuilder.build();
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            SocketAccess.doPrivilegedVoid(() -> { clientReference.get().putObject(putRequest); });
-        } catch (final AmazonClientException e) {
+            SocketAccess.doPrivilegedVoid(
+                () -> clientReference.get().putObject(putObjectRequest, RequestBody.fromInputStream(input, blobSize))
+            );
+        } catch (final SdkException e) {
             throw new IOException("Unable to upload object [" + blobName + "] using a single upload", e);
         }
     }
@@ -402,45 +564,46 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
         final String bucketName = blobStore.bucket();
         boolean success = false;
 
-        final InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(bucketName, blobName);
-        initRequest.setStorageClass(blobStore.getStorageClass());
-        initRequest.setCannedACL(blobStore.getCannedACL());
-        initRequest.setRequestMetricCollector(blobStore.multiPartUploadMetricCollector);
+        CreateMultipartUploadRequest.Builder createMultipartUploadRequestBuilder = CreateMultipartUploadRequest.builder()
+            .bucket(bucketName)
+            .key(blobName)
+            .storageClass(blobStore.getStorageClass())
+            .acl(blobStore.getCannedACL())
+            .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().multipartUploadMetricCollector));
+
         if (blobStore.serverSideEncryption()) {
-            final ObjectMetadata md = new ObjectMetadata();
-            md.setSSEAlgorithm(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION);
-            initRequest.setObjectMetadata(md);
+            createMultipartUploadRequestBuilder.serverSideEncryption(ServerSideEncryption.AES256);
         }
-        try (AmazonS3Reference clientReference = blobStore.clientReference()) {
 
-            uploadId.set(SocketAccess.doPrivileged(() -> clientReference.get().initiateMultipartUpload(initRequest).getUploadId()));
+        CreateMultipartUploadRequest createMultipartUploadRequest = createMultipartUploadRequestBuilder.build();
+        try (AmazonS3Reference clientReference = blobStore.clientReference()) {
+            uploadId.set(
+                SocketAccess.doPrivileged(() -> clientReference.get().createMultipartUpload(createMultipartUploadRequest).uploadId())
+            );
             if (Strings.isEmpty(uploadId.get())) {
                 throw new IOException("Failed to initialize multipart upload " + blobName);
             }
 
-            final List<PartETag> parts = new ArrayList<>();
+            final List<CompletedPart> parts = new ArrayList<>();
 
             long bytesCount = 0;
             for (int i = 1; i <= nbParts; i++) {
-                final UploadPartRequest uploadRequest = new UploadPartRequest();
-                uploadRequest.setBucketName(bucketName);
-                uploadRequest.setKey(blobName);
-                uploadRequest.setUploadId(uploadId.get());
-                uploadRequest.setPartNumber(i);
-                uploadRequest.setInputStream(input);
-                uploadRequest.setRequestMetricCollector(blobStore.multiPartUploadMetricCollector);
-
-                if (i < nbParts) {
-                    uploadRequest.setPartSize(partSize);
-                    uploadRequest.setLastPart(false);
-                } else {
-                    uploadRequest.setPartSize(lastPartSize);
-                    uploadRequest.setLastPart(true);
-                }
-                bytesCount += uploadRequest.getPartSize();
-
-                final UploadPartResult uploadResponse = SocketAccess.doPrivileged(() -> clientReference.get().uploadPart(uploadRequest));
-                parts.add(uploadResponse.getPartETag());
+                final UploadPartRequest uploadPartRequest = UploadPartRequest.builder()
+                    .bucket(bucketName)
+                    .key(blobName)
+                    .uploadId(uploadId.get())
+                    .partNumber(i)
+                    .contentLength((i < nbParts) ? partSize : lastPartSize)
+                    .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().multipartUploadMetricCollector))
+                    .build();
+
+                bytesCount += uploadPartRequest.contentLength();
+
+                final UploadPartResponse uploadResponse = SocketAccess.doPrivileged(
+                    () -> clientReference.get()
+                        .uploadPart(uploadPartRequest, RequestBody.fromInputStream(input, uploadPartRequest.contentLength()))
+                );
+                parts.add(CompletedPart.builder().partNumber(uploadPartRequest.partNumber()).eTag(uploadResponse.eTag()).build());
             }
 
             if (bytesCount != blobSize) {
@@ -449,21 +612,26 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
                 );
             }
 
-            final CompleteMultipartUploadRequest complRequest = new CompleteMultipartUploadRequest(
-                bucketName,
-                blobName,
-                uploadId.get(),
-                parts
-            );
-            complRequest.setRequestMetricCollector(blobStore.multiPartUploadMetricCollector);
-            SocketAccess.doPrivilegedVoid(() -> clientReference.get().completeMultipartUpload(complRequest));
+            CompleteMultipartUploadRequest completeMultipartUploadRequest = CompleteMultipartUploadRequest.builder()
+                .bucket(bucketName)
+                .key(blobName)
+                .uploadId(uploadId.get())
+                .multipartUpload(CompletedMultipartUpload.builder().parts(parts).build())
+                .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().multipartUploadMetricCollector))
+                .build();
+
+            SocketAccess.doPrivilegedVoid(() -> clientReference.get().completeMultipartUpload(completeMultipartUploadRequest));
             success = true;
 
-        } catch (final AmazonClientException e) {
+        } catch (final SdkException e) {
             throw new IOException("Unable to upload object [" + blobName + "] using multipart upload", e);
         } finally {
             if ((success == false) && Strings.hasLength(uploadId.get())) {
-                final AbortMultipartUploadRequest abortRequest = new AbortMultipartUploadRequest(bucketName, blobName, uploadId.get());
+                AbortMultipartUploadRequest abortRequest = AbortMultipartUploadRequest.builder()
+                    .bucket(bucketName)
+                    .key(blobName)
+                    .uploadId(uploadId.get())
+                    .build();
                 try (AmazonS3Reference clientReference = blobStore.clientReference()) {
                     SocketAccess.doPrivilegedVoid(() -> clientReference.get().abortMultipartUpload(abortRequest));
                 }
@@ -512,4 +680,71 @@ static Tuple<Long, Long> numberOfMultiparts(final long totalSize, final long par
             return Tuple.tuple(parts + 1, remaining);
         }
     }
+
+    /**
+     * Fetches a part of the blob from the S3 bucket and transforms it to an {@link InputStreamContainer}, which holds
+     * the stream and its related metadata.
+     * @param s3AsyncClient Async client to be utilized to fetch the object part
+     * @param bucketName Name of the S3 bucket
+     * @param blobKey Identifier of the blob for which the parts will be fetched
+     * @param partNumber Optional part number for the blob to be retrieved
+     * @return A future of {@link InputStreamContainer} containing the stream and stream metadata.
+     */
+    CompletableFuture<InputStreamContainer> getBlobPartInputStreamContainer(
+        S3AsyncClient s3AsyncClient,
+        String bucketName,
+        String blobKey,
+        @Nullable Integer partNumber
+    ) {
+        final boolean isMultipartObject = partNumber != null;
+        final GetObjectRequest.Builder getObjectRequestBuilder = GetObjectRequest.builder().bucket(bucketName).key(blobKey);
+
+        if (isMultipartObject) {
+            getObjectRequestBuilder.partNumber(partNumber);
+        }
+
+        return SocketAccess.doPrivileged(
+            () -> s3AsyncClient.getObject(getObjectRequestBuilder.build(), AsyncResponseTransformer.toBlockingInputStream())
+                .thenApply(response -> transformResponseToInputStreamContainer(response, isMultipartObject))
+        );
+    }
+
+    /**
+     * Transforms the stream response object from S3 into an {@link InputStreamContainer}
+     * @param streamResponse Response stream object from S3
+     * @param isMultipartObject Flag to denote a multipart object response
+     * @return {@link InputStreamContainer} containing the stream and stream metadata
+     */
+    // Package-Private for testing.
+    static InputStreamContainer transformResponseToInputStreamContainer(
+        ResponseInputStream<GetObjectResponse> streamResponse,
+        boolean isMultipartObject
+    ) {
+        final GetObjectResponse getObjectResponse = streamResponse.response();
+        final String contentRange = getObjectResponse.contentRange();
+        final Long contentLength = getObjectResponse.contentLength();
+        if ((isMultipartObject && contentRange == null) || contentLength == null) {
+            throw SdkException.builder().message("Failed to fetch required metadata for blob part").build();
+        }
+        final long offset = isMultipartObject ? HttpRangeUtils.getStartOffsetFromRangeHeader(getObjectResponse.contentRange()) : 0L;
+        return new InputStreamContainer(streamResponse, getObjectResponse.contentLength(), offset);
+    }
+
+    /**
+     * Retrieves the metadata like checksum, object size and parts for the provided blob within the S3 bucket.
+     * @param s3AsyncClient Async client to be utilized to fetch the metadata
+     * @param bucketName Name of the S3 bucket
+     * @param blobName Identifier of the blob for which the metadata will be fetched
+     * @return A future containing the metadata within {@link GetObjectAttributesResponse}
+     */
+    CompletableFuture<GetObjectAttributesResponse> getBlobMetadata(S3AsyncClient s3AsyncClient, String bucketName, String blobName) {
+        // Fetch blob metadata - part info, size, checksum
+        final GetObjectAttributesRequest getObjectAttributesRequest = GetObjectAttributesRequest.builder()
+            .bucket(bucketName)
+            .key(blobName)
+            .objectAttributes(ObjectAttributes.CHECKSUM, ObjectAttributes.OBJECT_SIZE, ObjectAttributes.OBJECT_PARTS)
+            .build();
+
+        return SocketAccess.doPrivileged(() -> s3AsyncClient.getObjectAttributes(getObjectAttributesRequest));
+    }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobStore.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobStore.java
index 90f8bbb6612d4..3dd373b5b9f32 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobStore.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobStore.java
@@ -32,12 +32,9 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.Request;
-import com.amazonaws.Response;
-import com.amazonaws.metrics.RequestMetricCollector;
-import com.amazonaws.services.s3.model.CannedAccessControlList;
-import com.amazonaws.services.s3.model.StorageClass;
-import com.amazonaws.util.AWSRequestMetrics;
+import software.amazon.awssdk.services.s3.model.ObjectCannedACL;
+import software.amazon.awssdk.services.s3.model.StorageClass;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
@@ -45,13 +42,19 @@
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.blobstore.BlobStoreException;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferManager;
 
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
-import java.util.concurrent.atomic.AtomicLong;
+
+import static org.opensearch.repositories.s3.S3Repository.BUCKET_SETTING;
+import static org.opensearch.repositories.s3.S3Repository.BUFFER_SIZE_SETTING;
+import static org.opensearch.repositories.s3.S3Repository.CANNED_ACL_SETTING;
+import static org.opensearch.repositories.s3.S3Repository.SERVER_SIDE_ENCRYPTION_SETTING;
+import static org.opensearch.repositories.s3.S3Repository.STORAGE_CLASS_SETTING;
 
 class S3BlobStore implements BlobStore {
 
@@ -59,78 +62,63 @@ class S3BlobStore implements BlobStore {
 
     private final S3Service service;
 
-    private final String bucket;
+    private final S3AsyncService s3AsyncService;
 
-    private final ByteSizeValue bufferSize;
+    private volatile String bucket;
 
-    private final boolean serverSideEncryption;
+    private volatile ByteSizeValue bufferSize;
 
-    private final CannedAccessControlList cannedACL;
+    private volatile boolean serverSideEncryption;
 
-    private final StorageClass storageClass;
+    private volatile ObjectCannedACL cannedACL;
 
-    private final RepositoryMetadata repositoryMetadata;
+    private volatile StorageClass storageClass;
 
-    private final Stats stats = new Stats();
+    private volatile RepositoryMetadata repositoryMetadata;
 
-    final RequestMetricCollector getMetricCollector;
-    final RequestMetricCollector listMetricCollector;
-    final RequestMetricCollector putMetricCollector;
-    final RequestMetricCollector multiPartUploadMetricCollector;
+    private final StatsMetricPublisher statsMetricPublisher = new StatsMetricPublisher();
+
+    private final AsyncTransferManager asyncTransferManager;
+    private final AsyncExecutorContainer priorityExecutorBuilder;
+    private final AsyncExecutorContainer normalExecutorBuilder;
+    private final boolean multipartUploadEnabled;
 
     S3BlobStore(
         S3Service service,
+        S3AsyncService s3AsyncService,
+        boolean multipartUploadEnabled,
         String bucket,
         boolean serverSideEncryption,
         ByteSizeValue bufferSize,
         String cannedACL,
         String storageClass,
-        RepositoryMetadata repositoryMetadata
+        RepositoryMetadata repositoryMetadata,
+        AsyncTransferManager asyncTransferManager,
+        AsyncExecutorContainer priorityExecutorBuilder,
+        AsyncExecutorContainer normalExecutorBuilder
     ) {
         this.service = service;
+        this.s3AsyncService = s3AsyncService;
+        this.multipartUploadEnabled = multipartUploadEnabled;
         this.bucket = bucket;
         this.serverSideEncryption = serverSideEncryption;
         this.bufferSize = bufferSize;
         this.cannedACL = initCannedACL(cannedACL);
         this.storageClass = initStorageClass(storageClass);
         this.repositoryMetadata = repositoryMetadata;
-        this.getMetricCollector = new RequestMetricCollector() {
-            @Override
-            public void collectMetrics(Request<?> request, Response<?> response) {
-                assert request.getHttpMethod().name().equals("GET");
-                stats.getCount.addAndGet(getRequestCount(request));
-            }
-        };
-        this.listMetricCollector = new RequestMetricCollector() {
-            @Override
-            public void collectMetrics(Request<?> request, Response<?> response) {
-                assert request.getHttpMethod().name().equals("GET");
-                stats.listCount.addAndGet(getRequestCount(request));
-            }
-        };
-        this.putMetricCollector = new RequestMetricCollector() {
-            @Override
-            public void collectMetrics(Request<?> request, Response<?> response) {
-                assert request.getHttpMethod().name().equals("PUT");
-                stats.putCount.addAndGet(getRequestCount(request));
-            }
-        };
-        this.multiPartUploadMetricCollector = new RequestMetricCollector() {
-            @Override
-            public void collectMetrics(Request<?> request, Response<?> response) {
-                assert request.getHttpMethod().name().equals("PUT") || request.getHttpMethod().name().equals("POST");
-                stats.postCount.addAndGet(getRequestCount(request));
-            }
-        };
+        this.asyncTransferManager = asyncTransferManager;
+        this.normalExecutorBuilder = normalExecutorBuilder;
+        this.priorityExecutorBuilder = priorityExecutorBuilder;
     }
 
-    private long getRequestCount(Request<?> request) {
-        Number requestCount = request.getAWSRequestMetrics().getTimingInfo().getCounter(AWSRequestMetrics.Field.RequestCount.name());
-        if (requestCount == null) {
-            logger.warn("Expected request count to be tracked for request [{}] but found not count.", request);
-            return 0L;
-        }
-        return requestCount.longValue();
+    @Override
+    public void reload(RepositoryMetadata repositoryMetadata) {
+        this.repositoryMetadata = repositoryMetadata;
+        this.bucket = BUCKET_SETTING.get(repositoryMetadata.settings());
+        this.serverSideEncryption = SERVER_SIDE_ENCRYPTION_SETTING.get(repositoryMetadata.settings());
+        this.bufferSize = BUFFER_SIZE_SETTING.get(repositoryMetadata.settings());
+        this.cannedACL = initCannedACL(CANNED_ACL_SETTING.get(repositoryMetadata.settings()));
+        this.storageClass = initStorageClass(STORAGE_CLASS_SETTING.get(repositoryMetadata.settings()));
     }
 
     @Override
@@ -142,6 +130,10 @@ public AmazonS3Reference clientReference() {
         return service.client(repositoryMetadata);
     }
 
+    public AmazonAsyncS3Reference asyncClientReference() {
+        return s3AsyncService.client(repositoryMetadata, priorityExecutorBuilder, normalExecutorBuilder);
+    }
+
     int getMaxRetries() {
         return service.settings(repositoryMetadata).maxRetries;
     }
@@ -165,15 +157,20 @@ public BlobContainer blobContainer(BlobPath path) {
 
     @Override
     public void close() throws IOException {
-        this.service.close();
+        if (service != null) {
+            this.service.close();
+        }
+        if (s3AsyncService != null) {
+            this.s3AsyncService.close();
+        }
     }
 
     @Override
     public Map<String, Long> stats() {
-        return stats.toMap();
+        return statsMetricPublisher.getStats().toMap();
     }
 
-    public CannedAccessControlList getCannedACL() {
+    public ObjectCannedACL getCannedACL() {
         return cannedACL;
     }
 
@@ -181,32 +178,36 @@ public StorageClass getStorageClass() {
         return storageClass;
     }
 
-    public static StorageClass initStorageClass(String storageClass) {
-        if ((storageClass == null) || storageClass.equals("")) {
-            return StorageClass.Standard;
+    public StatsMetricPublisher getStatsMetricPublisher() {
+        return statsMetricPublisher;
+    }
+
+    public static StorageClass initStorageClass(String storageClassStringValue) {
+        if ((storageClassStringValue == null) || storageClassStringValue.equals("")) {
+            return StorageClass.STANDARD;
         }
 
-        try {
-            final StorageClass _storageClass = StorageClass.fromValue(storageClass.toUpperCase(Locale.ENGLISH));
-            if (_storageClass.equals(StorageClass.Glacier)) {
-                throw new BlobStoreException("Glacier storage class is not supported");
-            }
+        final StorageClass storageClass = StorageClass.fromValue(storageClassStringValue.toUpperCase(Locale.ENGLISH));
+        if (storageClass.equals(StorageClass.GLACIER)) {
+            throw new BlobStoreException("Glacier storage class is not supported");
+        }
 
-            return _storageClass;
-        } catch (final IllegalArgumentException illegalArgumentException) {
-            throw new BlobStoreException("`" + storageClass + "` is not a valid S3 Storage Class.");
+        if (storageClass == StorageClass.UNKNOWN_TO_SDK_VERSION) {
+            throw new BlobStoreException("`" + storageClassStringValue + "` is not a valid S3 Storage Class.");
         }
+
+        return storageClass;
     }
 
     /**
      * Constructs canned acl from string
      */
-    public static CannedAccessControlList initCannedACL(String cannedACL) {
+    public static ObjectCannedACL initCannedACL(String cannedACL) {
         if ((cannedACL == null) || cannedACL.equals("")) {
-            return CannedAccessControlList.Private;
+            return ObjectCannedACL.PRIVATE;
         }
 
-        for (final CannedAccessControlList cur : CannedAccessControlList.values()) {
+        for (final ObjectCannedACL cur : ObjectCannedACL.values()) {
             if (cur.toString().equalsIgnoreCase(cannedACL)) {
                 return cur;
             }
@@ -215,23 +216,7 @@ public static CannedAccessControlList initCannedACL(String cannedACL) {
         throw new BlobStoreException("cannedACL is not valid: [" + cannedACL + "]");
     }
 
-    static class Stats {
-
-        final AtomicLong listCount = new AtomicLong();
-
-        final AtomicLong getCount = new AtomicLong();
-
-        final AtomicLong putCount = new AtomicLong();
-
-        final AtomicLong postCount = new AtomicLong();
-
-        Map<String, Long> toMap() {
-            final Map<String, Long> results = new HashMap<>();
-            results.put("GetObject", getCount.get());
-            results.put("ListObjects", listCount.get());
-            results.put("PutObject", putCount.get());
-            results.put("PutMultipartObject", postCount.get());
-            return results;
-        }
+    public AsyncTransferManager getAsyncTransferManager() {
+        return asyncTransferManager;
     }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3ClientSettings.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3ClientSettings.java
index e02c7cae89378..933136228b1bb 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3ClientSettings.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3ClientSettings.java
@@ -32,20 +32,26 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.Protocol;
-import org.opensearch.common.Strings;
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.repositories.s3.utils.Protocol;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.nio.file.Path;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Locale;
@@ -67,6 +73,29 @@ final class S3ClientSettings {
     /** Placeholder client name for normalizing client settings in the repository settings. */
     private static final String PLACEHOLDER_CLIENT = "placeholder";
 
+    // Properties to support using IAM Roles for Service Accounts (IRSA)
+
+    /** The identity token file for connecting to s3. */
+    static final Setting.AffixSetting<String> IDENTITY_TOKEN_FILE_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "identity_token_file",
+        key -> SecureSetting.simpleString(key, Property.NodeScope)
+    );
+
+    /** The role ARN (Amazon Resource Name) for connecting to s3. */
+    static final Setting.AffixSetting<SecureString> ROLE_ARN_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "role_arn",
+        key -> SecureSetting.secureString(key, null)
+    );
+
+    /** The role session name for connecting to s3. */
+    static final Setting.AffixSetting<SecureString> ROLE_SESSION_NAME_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "role_session_name",
+        key -> SecureSetting.secureString(key, null)
+    );
+
     /** The access key (ie login id) for connecting to s3. */
     static final Setting.AffixSetting<SecureString> ACCESS_KEY_SETTING = Setting.affixKeySetting(
         PREFIX,
@@ -141,21 +170,63 @@ final class S3ClientSettings {
     static final Setting.AffixSetting<TimeValue> READ_TIMEOUT_SETTING = Setting.affixKeySetting(
         PREFIX,
         "read_timeout",
-        key -> Setting.timeSetting(key, TimeValue.timeValueMillis(ClientConfiguration.DEFAULT_SOCKET_TIMEOUT), Property.NodeScope)
+        key -> Setting.timeSetting(key, TimeValue.timeValueMillis(50_000), Property.NodeScope)
+    );
+
+    /** The request timeout for connecting to s3. */
+    static final Setting.AffixSetting<TimeValue> REQUEST_TIMEOUT_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "request_timeout",
+        key -> Setting.timeSetting(key, TimeValue.timeValueMinutes(2), Property.NodeScope)
+    );
+
+    /** The connection timeout for connecting to s3. */
+    static final Setting.AffixSetting<TimeValue> CONNECTION_TIMEOUT_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "connection_timeout",
+        key -> Setting.timeSetting(key, TimeValue.timeValueSeconds(10), Property.NodeScope)
+    );
+
+    /** The connection TTL for connecting to s3. */
+    static final Setting.AffixSetting<TimeValue> CONNECTION_TTL_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "connection_ttl",
+        key -> Setting.timeSetting(key, TimeValue.timeValueMillis(5000), Property.NodeScope)
+    );
+
+    /** The maximum connections to s3. */
+    static final Setting.AffixSetting<Integer> MAX_CONNECTIONS_SETTING = Setting.affixKeySetting(
+        PREFIX,
+        "max_connections",
+        key -> Setting.intSetting(key, 100, Property.NodeScope)
+    );
+
+    /** Connection acquisition timeout for new connections to S3. */
+    static final Setting.AffixSetting<TimeValue> CONNECTION_ACQUISITION_TIMEOUT = Setting.affixKeySetting(
+        PREFIX,
+        "connection_acquisition_timeout",
+        key -> Setting.timeSetting(key, TimeValue.timeValueMinutes(2), Property.NodeScope)
+    );
+
+    /** The maximum pending connections to S3. */
+    static final Setting.AffixSetting<Integer> MAX_PENDING_CONNECTION_ACQUIRES = Setting.affixKeySetting(
+        PREFIX,
+        "max_pending_connection_acquires",
+        key -> Setting.intSetting(key, 10_000, Property.NodeScope)
     );
 
     /** The number of retries to use when an s3 request fails. */
     static final Setting.AffixSetting<Integer> MAX_RETRIES_SETTING = Setting.affixKeySetting(
         PREFIX,
         "max_retries",
-        key -> Setting.intSetting(key, ClientConfiguration.DEFAULT_RETRY_POLICY.getMaxErrorRetry(), 0, Property.NodeScope)
+        key -> Setting.intSetting(key, 3, 0, Property.NodeScope)
     );
 
     /** Whether retries should be throttled (ie use backoff). */
     static final Setting.AffixSetting<Boolean> USE_THROTTLE_RETRIES_SETTING = Setting.affixKeySetting(
         PREFIX,
         "use_throttle_retries",
-        key -> Setting.boolSetting(key, ClientConfiguration.DEFAULT_THROTTLE_RETRIES, Property.NodeScope)
+        key -> Setting.boolSetting(key, true, Property.NodeScope)
     );
 
     /** Whether the s3 client should use path style access. */
@@ -187,7 +258,10 @@ final class S3ClientSettings {
     );
 
     /** Credentials to authenticate with s3. */
-    final S3BasicCredentials credentials;
+    final AwsCredentials credentials;
+
+    /** Credentials to authenticate with s3 using IAM Roles for Service Accounts (IRSA). */
+    final IrsaCredentials irsaCredentials;
 
     /** The s3 endpoint the client should talk to, or empty string to use the default. */
     final String endpoint;
@@ -201,6 +275,21 @@ final class S3ClientSettings {
     /** The read timeout for the s3 client. */
     final int readTimeoutMillis;
 
+    /** The request timeout for the s3 client */
+    final int requestTimeoutMillis;
+
+    /** The connection timeout for the s3 client */
+    final int connectionTimeoutMillis;
+
+    /** The connection TTL for the s3 client */
+    final int connectionTTLMillis;
+
+    /** The max number of connections for the s3 client */
+    final int maxConnections;
+
+    /** The connnection acquisition timeout for the s3 async client */
+    final int connectionAcquisitionTimeoutMillis;
+
     /** The number of retries to use for the s3 client. */
     final int maxRetries;
 
@@ -220,10 +309,16 @@ final class S3ClientSettings {
     final String signerOverride;
 
     private S3ClientSettings(
-        S3BasicCredentials credentials,
+        AwsCredentials credentials,
+        IrsaCredentials irsaCredentials,
         String endpoint,
         Protocol protocol,
         int readTimeoutMillis,
+        int requestTimeoutMillis,
+        int connectionTimeoutMillis,
+        int connectionTTLMillis,
+        int maxConnections,
+        int connectionAcquisitionTimeoutMillis,
         int maxRetries,
         boolean throttleRetries,
         boolean pathStyleAccess,
@@ -233,9 +328,15 @@ private S3ClientSettings(
         ProxySettings proxySettings
     ) {
         this.credentials = credentials;
+        this.irsaCredentials = irsaCredentials;
         this.endpoint = endpoint;
         this.protocol = protocol;
         this.readTimeoutMillis = readTimeoutMillis;
+        this.requestTimeoutMillis = requestTimeoutMillis;
+        this.connectionTimeoutMillis = connectionTimeoutMillis;
+        this.connectionTTLMillis = connectionTTLMillis;
+        this.maxConnections = maxConnections;
+        this.connectionAcquisitionTimeoutMillis = connectionAcquisitionTimeoutMillis;
         this.maxRetries = maxRetries;
         this.throttleRetries = throttleRetries;
         this.pathStyleAccess = pathStyleAccess;
@@ -267,6 +368,24 @@ S3ClientSettings refine(Settings repositorySettings) {
         final int newReadTimeoutMillis = Math.toIntExact(
             getRepoSettingOrDefault(READ_TIMEOUT_SETTING, normalizedSettings, TimeValue.timeValueMillis(readTimeoutMillis)).millis()
         );
+        final int newRequestTimeoutMillis = Math.toIntExact(
+            getRepoSettingOrDefault(REQUEST_TIMEOUT_SETTING, normalizedSettings, TimeValue.timeValueMillis(requestTimeoutMillis)).millis()
+        );
+        final int newConnectionTimeoutMillis = Math.toIntExact(
+            getRepoSettingOrDefault(CONNECTION_TIMEOUT_SETTING, normalizedSettings, TimeValue.timeValueMillis(connectionTimeoutMillis))
+                .millis()
+        );
+        final int newConnectionTTLMillis = Math.toIntExact(
+            getRepoSettingOrDefault(CONNECTION_TTL_SETTING, normalizedSettings, TimeValue.timeValueMillis(connectionTTLMillis)).millis()
+        );
+        final int newConnectionAcquisitionTimeoutMillis = Math.toIntExact(
+            getRepoSettingOrDefault(
+                CONNECTION_ACQUISITION_TIMEOUT,
+                normalizedSettings,
+                TimeValue.timeValueMillis(connectionAcquisitionTimeoutMillis)
+            ).millis()
+        );
+        final int newMaxConnections = Math.toIntExact(getRepoSettingOrDefault(MAX_CONNECTIONS_SETTING, normalizedSettings, maxConnections));
         final int newMaxRetries = getRepoSettingOrDefault(MAX_RETRIES_SETTING, normalizedSettings, maxRetries);
         final boolean newThrottleRetries = getRepoSettingOrDefault(USE_THROTTLE_RETRIES_SETTING, normalizedSettings, throttleRetries);
         final boolean newPathStyleAccess = getRepoSettingOrDefault(USE_PATH_STYLE_ACCESS, normalizedSettings, pathStyleAccess);
@@ -275,7 +394,7 @@ S3ClientSettings refine(Settings repositorySettings) {
             normalizedSettings,
             disableChunkedEncoding
         );
-        final S3BasicCredentials newCredentials;
+        final AwsCredentials newCredentials;
         if (checkDeprecatedCredentials(repositorySettings)) {
             newCredentials = loadDeprecatedCredentials(repositorySettings);
         } else {
@@ -288,6 +407,11 @@ S3ClientSettings refine(Settings repositorySettings) {
             && Objects.equals(proxySettings.getHostName(), newProxyHost)
             && proxySettings.getPort() == newProxyPort
             && newReadTimeoutMillis == readTimeoutMillis
+            && newRequestTimeoutMillis == requestTimeoutMillis
+            && newConnectionTimeoutMillis == connectionTimeoutMillis
+            && newConnectionTTLMillis == connectionTTLMillis
+            && newMaxConnections == maxConnections
+            && newConnectionAcquisitionTimeoutMillis == connectionAcquisitionTimeoutMillis
             && maxRetries == newMaxRetries
             && newThrottleRetries == throttleRetries
             && Objects.equals(credentials, newCredentials)
@@ -301,9 +425,15 @@ S3ClientSettings refine(Settings repositorySettings) {
         validateInetAddressFor(newProxyHost);
         return new S3ClientSettings(
             newCredentials,
+            irsaCredentials,
             newEndpoint,
             newProtocol,
             newReadTimeoutMillis,
+            newRequestTimeoutMillis,
+            newConnectionTimeoutMillis,
+            newConnectionTTLMillis,
+            newMaxConnections,
+            newConnectionAcquisitionTimeoutMillis,
             newMaxRetries,
             newThrottleRetries,
             newPathStyleAccess,
@@ -319,16 +449,16 @@ S3ClientSettings refine(Settings repositorySettings) {
      *
      * Note this will always at least return a client named "default".
      */
-    static Map<String, S3ClientSettings> load(Settings settings) {
+    static Map<String, S3ClientSettings> load(final Settings settings, final Path configPath) {
         final Set<String> clientNames = settings.getGroups(PREFIX).keySet();
         final Map<String, S3ClientSettings> clients = new HashMap<>();
         for (final String clientName : clientNames) {
-            clients.put(clientName, getClientSettings(settings, clientName));
+            clients.put(clientName, getClientSettings(settings, clientName, configPath));
         }
         if (clients.containsKey("default") == false) {
             // this won't find any settings under the default client,
             // but it will pull all the fallback static settings
-            clients.put("default", getClientSettings(settings, "default"));
+            clients.put("default", getClientSettings(settings, "default", configPath));
         }
         return Collections.unmodifiableMap(clients);
     }
@@ -358,17 +488,17 @@ static boolean checkDeprecatedCredentials(Settings repositorySettings) {
     }
 
     // backcompat for reading keys out of repository settings (clusterState)
-    private static S3BasicCredentials loadDeprecatedCredentials(Settings repositorySettings) {
+    private static AwsCredentials loadDeprecatedCredentials(Settings repositorySettings) {
         assert checkDeprecatedCredentials(repositorySettings);
         try (
             SecureString key = S3Repository.ACCESS_KEY_SETTING.get(repositorySettings);
             SecureString secret = S3Repository.SECRET_KEY_SETTING.get(repositorySettings)
         ) {
-            return new S3BasicCredentials(key.toString(), secret.toString());
+            return AwsBasicCredentials.create(key.toString(), secret.toString());
         }
     }
 
-    private static S3BasicCredentials loadCredentials(Settings settings, String clientName) {
+    private static AwsCredentials loadCredentials(Settings settings, String clientName) {
         try (
             SecureString accessKey = getConfigValue(settings, clientName, ACCESS_KEY_SETTING);
             SecureString secretKey = getConfigValue(settings, clientName, SECRET_KEY_SETTING);
@@ -377,9 +507,9 @@ private static S3BasicCredentials loadCredentials(Settings settings, String clie
             if (accessKey.length() != 0) {
                 if (secretKey.length() != 0) {
                     if (sessionToken.length() != 0) {
-                        return new S3BasicSessionCredentials(accessKey.toString(), secretKey.toString(), sessionToken.toString());
+                        return AwsSessionCredentials.create(accessKey.toString(), secretKey.toString(), sessionToken.toString());
                     } else {
-                        return new S3BasicCredentials(accessKey.toString(), secretKey.toString());
+                        return AwsBasicCredentials.create(accessKey.toString(), secretKey.toString());
                     }
                 } else {
                     throw new IllegalArgumentException("Missing secret key for s3 client [" + clientName + "]");
@@ -396,15 +526,44 @@ private static S3BasicCredentials loadCredentials(Settings settings, String clie
         }
     }
 
+    @SuppressForbidden(reason = "PathUtils#get")
+    private static IrsaCredentials loadIrsaCredentials(Settings settings, String clientName, Path configPath) {
+        String identityTokenFile = getConfigValue(settings, clientName, IDENTITY_TOKEN_FILE_SETTING);
+        if (identityTokenFile.length() != 0) {
+            final Path identityTokenFilePath = PathUtils.get(identityTokenFile);
+            // If the path is not absolute, resolve it relatively to config path
+            if (!identityTokenFilePath.isAbsolute()) {
+                identityTokenFile = PathUtils.get(new Path[] { configPath }, identityTokenFile).toString();
+            }
+        }
+
+        try (
+            SecureString roleArn = getConfigValue(settings, clientName, ROLE_ARN_SETTING);
+            SecureString roleSessionName = getConfigValue(settings, clientName, ROLE_SESSION_NAME_SETTING)
+        ) {
+            if (identityTokenFile.length() != 0 || roleArn.length() != 0 || roleSessionName.length() != 0) {
+                return new IrsaCredentials(identityTokenFile.toString(), roleArn.toString(), roleSessionName.toString());
+            }
+
+            return null;
+        }
+    }
+
     // pkg private for tests
     /** Parse settings for a single client. */
-    static S3ClientSettings getClientSettings(final Settings settings, final String clientName) {
+    static S3ClientSettings getClientSettings(final Settings settings, final String clientName, final Path configPath) {
         final Protocol awsProtocol = getConfigValue(settings, clientName, PROTOCOL_SETTING);
         return new S3ClientSettings(
             S3ClientSettings.loadCredentials(settings, clientName),
+            S3ClientSettings.loadIrsaCredentials(settings, clientName, configPath),
             getConfigValue(settings, clientName, ENDPOINT_SETTING),
             awsProtocol,
             Math.toIntExact(getConfigValue(settings, clientName, READ_TIMEOUT_SETTING).millis()),
+            Math.toIntExact(getConfigValue(settings, clientName, REQUEST_TIMEOUT_SETTING).millis()),
+            Math.toIntExact(getConfigValue(settings, clientName, CONNECTION_TIMEOUT_SETTING).millis()),
+            Math.toIntExact(getConfigValue(settings, clientName, CONNECTION_TTL_SETTING).millis()),
+            Math.toIntExact(getConfigValue(settings, clientName, MAX_CONNECTIONS_SETTING)),
+            Math.toIntExact(getConfigValue(settings, clientName, CONNECTION_ACQUISITION_TIMEOUT).millis()),
             getConfigValue(settings, clientName, MAX_RETRIES_SETTING),
             getConfigValue(settings, clientName, USE_THROTTLE_RETRIES_SETTING),
             getConfigValue(settings, clientName, USE_PATH_STYLE_ACCESS),
@@ -474,6 +633,11 @@ public boolean equals(final Object o) {
         }
         final S3ClientSettings that = (S3ClientSettings) o;
         return readTimeoutMillis == that.readTimeoutMillis
+            && requestTimeoutMillis == that.requestTimeoutMillis
+            && connectionTimeoutMillis == that.connectionTimeoutMillis
+            && connectionTTLMillis == that.connectionTTLMillis
+            && maxConnections == that.maxConnections
+            && connectionAcquisitionTimeoutMillis == that.connectionAcquisitionTimeoutMillis
             && maxRetries == that.maxRetries
             && throttleRetries == that.throttleRetries
             && Objects.equals(credentials, that.credentials)
@@ -482,7 +646,8 @@ public boolean equals(final Object o) {
             && proxySettings.equals(that.proxySettings)
             && Objects.equals(disableChunkedEncoding, that.disableChunkedEncoding)
             && Objects.equals(region, that.region)
-            && Objects.equals(signerOverride, that.signerOverride);
+            && Objects.equals(signerOverride, that.signerOverride)
+            && Objects.equals(irsaCredentials, that.irsaCredentials);
     }
 
     @Override
@@ -493,6 +658,11 @@ public int hashCode() {
             protocol,
             proxySettings,
             readTimeoutMillis,
+            requestTimeoutMillis,
+            connectionTimeoutMillis,
+            connectionTTLMillis,
+            maxConnections,
+            connectionAcquisitionTimeoutMillis,
             maxRetries,
             throttleRetries,
             disableChunkedEncoding,
@@ -512,4 +682,51 @@ private static <T> T getRepoSettingOrDefault(Setting.AffixSetting<T> setting, Se
         }
         return defaultValue;
     }
+
+    /**
+     * Class to store IAM Roles for Service Accounts (IRSA) credentials
+     * See please: https://docs.aws.amazon.com/eks/latest/userguide/iam-roles-for-service-accounts.html
+     */
+    static class IrsaCredentials {
+        private final String identityTokenFile;
+        private final String roleArn;
+        private final String roleSessionName;
+
+        IrsaCredentials(String identityTokenFile, String roleArn, String roleSessionName) {
+            this.identityTokenFile = Strings.isNullOrEmpty(identityTokenFile) ? null : identityTokenFile;
+            this.roleArn = Strings.isNullOrEmpty(roleArn) ? null : roleArn;
+            this.roleSessionName = Strings.isNullOrEmpty(roleSessionName) ? "s3-sdk-java-" + System.currentTimeMillis() : roleSessionName;
+        }
+
+        public String getIdentityTokenFile() {
+            return identityTokenFile;
+        }
+
+        public String getRoleArn() {
+            return roleArn;
+        }
+
+        public String getRoleSessionName() {
+            return roleSessionName;
+        }
+
+        @Override
+        public boolean equals(final Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            final IrsaCredentials that = (IrsaCredentials) o;
+            return Objects.equals(identityTokenFile, that.identityTokenFile)
+                && Objects.equals(roleArn, that.roleArn)
+                && Objects.equals(roleSessionName, that.roleSessionName);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(identityTokenFile, roleArn, roleSessionName);
+        }
+    }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Repository.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Repository.java
index c8377949a6842..0e311c9419b24 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Repository.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Repository.java
@@ -32,41 +32,51 @@
 
 package org.opensearch.repositories.s3;
 
+import software.amazon.awssdk.services.s3.model.ObjectCannedACL;
+import software.amazon.awssdk.services.s3.model.StorageClass;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.BlobStoreException;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.repositories.RepositoryData;
 import org.opensearch.repositories.RepositoryException;
 import org.opensearch.repositories.ShardGenerations;
 import org.opensearch.repositories.blobstore.MeteredBlobStoreRepository;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferManager;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
+import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
@@ -82,7 +92,6 @@
  * <dt>{@code concurrent_streams}</dt><dd>Number of concurrent read/write stream (per repository on each node). Defaults to 5.</dd>
  * <dt>{@code chunk_size}</dt>
  * <dd>Large file can be divided into chunks. This parameter specifies the chunk size. Defaults to not chucked.</dd>
- * <dt>{@code compress}</dt><dd>If set to true metadata files will be stored compressed. Defaults to false.</dd>
  * </dl>
  */
 class S3Repository extends MeteredBlobStoreRepository {
@@ -109,6 +118,11 @@ class S3Repository extends MeteredBlobStoreRepository {
         ByteSizeUnit.BYTES
     );
 
+    private static final ByteSizeValue DEFAULT_MULTIPART_UPLOAD_MINIMUM_PART_SIZE = new ByteSizeValue(
+        ByteSizeUnit.MB.toBytes(16),
+        ByteSizeUnit.BYTES
+    );
+
     static final Setting<String> BUCKET_SETTING = Setting.simpleString("bucket");
 
     /**
@@ -152,6 +166,26 @@ class S3Repository extends MeteredBlobStoreRepository {
         MAX_PART_SIZE_USING_MULTIPART
     );
 
+    /**
+     * Minimum part size for parallel multipart uploads
+     */
+    static final Setting<ByteSizeValue> PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING = Setting.byteSizeSetting(
+        "parallel_multipart_upload.minimum_part_size",
+        DEFAULT_MULTIPART_UPLOAD_MINIMUM_PART_SIZE,
+        MIN_PART_SIZE_USING_MULTIPART,
+        MAX_PART_SIZE_USING_MULTIPART,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * This setting controls whether parallel multipart uploads will be used when calling S3 or not
+     */
+    public static Setting<Boolean> PARALLEL_MULTIPART_UPLOAD_ENABLED_SETTING = Setting.boolSetting(
+        "parallel_multipart_upload.enabled",
+        true,
+        Setting.Property.NodeScope
+    );
+
     /**
      * Big files can be broken down into chunks during snapshotting if needed. Defaults to 1g.
      */
@@ -162,12 +196,6 @@ class S3Repository extends MeteredBlobStoreRepository {
         new ByteSizeValue(5, ByteSizeUnit.TB)
     );
 
-    /**
-     * When set to true metadata files are stored in compressed format. This setting doesn’t affect index
-     * files that are already compressed by default. Defaults to false.
-     */
-    static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", false);
-
     /**
      * Sets the S3 storage class type for the backup files. Values may be standard, reduced_redundancy,
      * standard_ia, onezone_ia and intelligent_tiering. Defaults to standard.
@@ -207,21 +235,19 @@ class S3Repository extends MeteredBlobStoreRepository {
 
     private final S3Service service;
 
-    private final String bucket;
-
-    private final ByteSizeValue bufferSize;
+    private volatile String bucket;
 
-    private final ByteSizeValue chunkSize;
+    private volatile ByteSizeValue bufferSize;
 
-    private final BlobPath basePath;
+    private volatile ByteSizeValue chunkSize;
 
-    private final boolean serverSideEncryption;
+    private volatile BlobPath basePath;
 
-    private final String storageClass;
+    private volatile boolean serverSideEncryption;
 
-    private final String cannedACL;
+    private volatile String storageClass;
 
-    private final RepositoryMetadata repositoryMetadata;
+    private volatile String cannedACL;
 
     /**
      * Time period to delay repository operations by after finalizing or deleting a snapshot.
@@ -229,93 +255,74 @@ class S3Repository extends MeteredBlobStoreRepository {
      */
     private final TimeValue coolDown;
 
-    /**
-     * Constructs an s3 backed repository
-     */
+    private final AsyncTransferManager asyncUploadUtils;
+    private final S3AsyncService s3AsyncService;
+    private final boolean multipartUploadEnabled;
+    private final AsyncExecutorContainer priorityExecutorBuilder;
+    private final AsyncExecutorContainer normalExecutorBuilder;
+    private final Path pluginConfigPath;
+
+    // Used by test classes
     S3Repository(
         final RepositoryMetadata metadata,
         final NamedXContentRegistry namedXContentRegistry,
         final S3Service service,
         final ClusterService clusterService,
-        final RecoverySettings recoverySettings
+        final RecoverySettings recoverySettings,
+        final AsyncTransferManager asyncUploadUtils,
+        final AsyncExecutorContainer priorityExecutorBuilder,
+        final AsyncExecutorContainer normalExecutorBuilder,
+        final S3AsyncService s3AsyncService,
+        final boolean multipartUploadEnabled
     ) {
-        super(
+        this(
             metadata,
-            COMPRESS_SETTING.get(metadata.settings()),
             namedXContentRegistry,
+            service,
             clusterService,
             recoverySettings,
-            buildLocation(metadata)
+            asyncUploadUtils,
+            priorityExecutorBuilder,
+            normalExecutorBuilder,
+            s3AsyncService,
+            multipartUploadEnabled,
+            Path.of("")
         );
-        this.service = service;
-
-        this.repositoryMetadata = metadata;
-
-        // Parse and validate the user's S3 Storage Class setting
-        this.bucket = BUCKET_SETTING.get(metadata.settings());
-        if (bucket == null) {
-            throw new RepositoryException(metadata.name(), "No bucket defined for s3 repository");
-        }
-
-        this.bufferSize = BUFFER_SIZE_SETTING.get(metadata.settings());
-        this.chunkSize = CHUNK_SIZE_SETTING.get(metadata.settings());
-
-        // We make sure that chunkSize is bigger or equal than/to bufferSize
-        if (this.chunkSize.getBytes() < bufferSize.getBytes()) {
-            throw new RepositoryException(
-                metadata.name(),
-                CHUNK_SIZE_SETTING.getKey()
-                    + " ("
-                    + this.chunkSize
-                    + ") can't be lower than "
-                    + BUFFER_SIZE_SETTING.getKey()
-                    + " ("
-                    + bufferSize
-                    + ")."
-            );
-        }
-
-        final String basePath = BASE_PATH_SETTING.get(metadata.settings());
-        if (Strings.hasLength(basePath)) {
-            this.basePath = new BlobPath().add(basePath);
-        } else {
-            this.basePath = BlobPath.cleanPath();
-        }
-
-        this.serverSideEncryption = SERVER_SIDE_ENCRYPTION_SETTING.get(metadata.settings());
+    }
 
-        this.storageClass = STORAGE_CLASS_SETTING.get(metadata.settings());
-        this.cannedACL = CANNED_ACL_SETTING.get(metadata.settings());
+    /**
+     * Constructs an s3 backed repository
+     */
+    S3Repository(
+        final RepositoryMetadata metadata,
+        final NamedXContentRegistry namedXContentRegistry,
+        final S3Service service,
+        final ClusterService clusterService,
+        final RecoverySettings recoverySettings,
+        final AsyncTransferManager asyncUploadUtils,
+        final AsyncExecutorContainer priorityExecutorBuilder,
+        final AsyncExecutorContainer normalExecutorBuilder,
+        final S3AsyncService s3AsyncService,
+        final boolean multipartUploadEnabled,
+        Path pluginConfigPath
+    ) {
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings, buildLocation(metadata));
+        this.service = service;
+        this.s3AsyncService = s3AsyncService;
+        this.multipartUploadEnabled = multipartUploadEnabled;
+        this.pluginConfigPath = pluginConfigPath;
+        this.asyncUploadUtils = asyncUploadUtils;
+        this.priorityExecutorBuilder = priorityExecutorBuilder;
+        this.normalExecutorBuilder = normalExecutorBuilder;
 
-        if (S3ClientSettings.checkDeprecatedCredentials(metadata.settings())) {
-            // provided repository settings
-            deprecationLogger.deprecate(
-                "s3_repository_secret_settings",
-                "Using s3 access/secret key from repository settings. Instead "
-                    + "store these in named clients and the opensearch keystore for secure settings."
-            );
-        }
+        validateRepositoryMetadata(metadata);
+        readRepositoryMetadata();
 
         coolDown = COOLDOWN_PERIOD.get(metadata.settings());
-
-        logger.debug(
-            "using bucket [{}], chunk_size [{}], server_side_encryption [{}], buffer_size [{}], cannedACL [{}], storageClass [{}]",
-            bucket,
-            chunkSize,
-            serverSideEncryption,
-            bufferSize,
-            cannedACL,
-            storageClass
-        );
     }
 
     private static Map<String, String> buildLocation(RepositoryMetadata metadata) {
-        return org.opensearch.common.collect.Map.of(
-            "base_path",
-            BASE_PATH_SETTING.get(metadata.settings()),
-            "bucket",
-            BUCKET_SETTING.get(metadata.settings())
-        );
+        return Map.of("base_path", BASE_PATH_SETTING.get(metadata.settings()), "bucket", BUCKET_SETTING.get(metadata.settings()));
     }
 
     /**
@@ -410,10 +417,23 @@ private void logCooldownInfo() {
 
     @Override
     protected S3BlobStore createBlobStore() {
-        return new S3BlobStore(service, bucket, serverSideEncryption, bufferSize, cannedACL, storageClass, repositoryMetadata);
+        return new S3BlobStore(
+            service,
+            s3AsyncService,
+            multipartUploadEnabled,
+            bucket,
+            serverSideEncryption,
+            bufferSize,
+            cannedACL,
+            storageClass,
+            metadata,
+            asyncUploadUtils,
+            priorityExecutorBuilder,
+            normalExecutorBuilder
+        );
     }
 
-    // only use for testing
+    // only use for testing (S3RepositoryTests)
     @Override
     protected BlobStore getBlobStore() {
         return super.getBlobStore();
@@ -424,11 +444,142 @@ public BlobPath basePath() {
         return basePath;
     }
 
+    @Override
+    public boolean isReloadable() {
+        return true;
+    }
+
+    @Override
+    public void reload(RepositoryMetadata newRepositoryMetadata) {
+        if (isReloadable() == false) {
+            return;
+        }
+
+        // Reload configs for S3Repository
+        super.reload(newRepositoryMetadata);
+        readRepositoryMetadata();
+
+        // Reload configs for S3RepositoryPlugin
+        final Map<String, S3ClientSettings> clientsSettings = S3ClientSettings.load(metadata.settings(), pluginConfigPath);
+        service.refreshAndClearCache(clientsSettings);
+        s3AsyncService.refreshAndClearCache(clientsSettings);
+
+        // Reload configs for S3BlobStore
+        BlobStore blobStore = getBlobStore();
+        blobStore.reload(metadata);
+    }
+
+    /**
+     * Reloads the values derived from the Repository Metadata
+     */
+    private void readRepositoryMetadata() {
+        this.bucket = BUCKET_SETTING.get(metadata.settings());
+        this.bufferSize = BUFFER_SIZE_SETTING.get(metadata.settings());
+        this.chunkSize = CHUNK_SIZE_SETTING.get(metadata.settings());
+        final String basePath = BASE_PATH_SETTING.get(metadata.settings());
+        if (Strings.hasLength(basePath)) {
+            this.basePath = new BlobPath().add(basePath);
+        } else {
+            this.basePath = BlobPath.cleanPath();
+        }
+
+        this.serverSideEncryption = SERVER_SIDE_ENCRYPTION_SETTING.get(metadata.settings());
+        this.storageClass = STORAGE_CLASS_SETTING.get(metadata.settings());
+        this.cannedACL = CANNED_ACL_SETTING.get(metadata.settings());
+        if (S3ClientSettings.checkDeprecatedCredentials(metadata.settings())) {
+            // provided repository settings
+            deprecationLogger.deprecate(
+                "s3_repository_secret_settings",
+                "Using s3 access/secret key from repository settings. Instead "
+                    + "store these in named clients and the opensearch keystore for secure settings."
+            );
+        }
+
+        logger.debug(
+            "using bucket [{}], chunk_size [{}], server_side_encryption [{}], buffer_size [{}], cannedACL [{}], storageClass [{}]",
+            bucket,
+            chunkSize,
+            serverSideEncryption,
+            bufferSize,
+            cannedACL,
+            storageClass
+        );
+    }
+
+    @Override
+    public void validateMetadata(RepositoryMetadata newRepositoryMetadata) {
+        super.validateMetadata(newRepositoryMetadata);
+        validateRepositoryMetadata(newRepositoryMetadata);
+    }
+
+    private void validateRepositoryMetadata(RepositoryMetadata newRepositoryMetadata) {
+        Settings settings = newRepositoryMetadata.settings();
+        if (BUCKET_SETTING.get(settings) == null) {
+            throw new RepositoryException(newRepositoryMetadata.name(), "No bucket defined for s3 repository");
+        }
+
+        // We make sure that chunkSize is bigger or equal than/to bufferSize
+        if (CHUNK_SIZE_SETTING.get(settings).getBytes() < BUFFER_SIZE_SETTING.get(settings).getBytes()) {
+            throw new RepositoryException(
+                newRepositoryMetadata.name(),
+                CHUNK_SIZE_SETTING.getKey()
+                    + " ("
+                    + CHUNK_SIZE_SETTING.get(settings)
+                    + ") can't be lower than "
+                    + BUFFER_SIZE_SETTING.getKey()
+                    + " ("
+                    + BUFFER_SIZE_SETTING.get(settings)
+                    + ")."
+            );
+        }
+
+        validateStorageClass(STORAGE_CLASS_SETTING.get(settings));
+        validateCannedACL(CANNED_ACL_SETTING.get(settings));
+    }
+
+    private static void validateStorageClass(String storageClassStringValue) {
+        if ((storageClassStringValue == null) || storageClassStringValue.equals("")) {
+            return;
+        }
+
+        final StorageClass storageClass = StorageClass.fromValue(storageClassStringValue.toUpperCase(Locale.ENGLISH));
+        if (storageClass.equals(StorageClass.GLACIER)) {
+            throw new BlobStoreException("Glacier storage class is not supported");
+        }
+
+        if (storageClass == StorageClass.UNKNOWN_TO_SDK_VERSION) {
+            throw new BlobStoreException("`" + storageClassStringValue + "` is not a valid S3 Storage Class.");
+        }
+    }
+
+    private static void validateCannedACL(String cannedACLStringValue) {
+        if ((cannedACLStringValue == null) || cannedACLStringValue.equals("")) {
+            return;
+        }
+
+        for (final ObjectCannedACL cur : ObjectCannedACL.values()) {
+            if (cur.toString().equalsIgnoreCase(cannedACLStringValue)) {
+                return;
+            }
+        }
+
+        throw new BlobStoreException("cannedACL is not valid: [" + cannedACLStringValue + "]");
+    }
+
     @Override
     protected ByteSizeValue chunkSize() {
         return chunkSize;
     }
 
+    @Override
+    public List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        List<Setting<?>> restrictedSettings = new ArrayList<>();
+        restrictedSettings.addAll(super.getRestrictedSystemRepositorySettings());
+        restrictedSettings.add(BUCKET_SETTING);
+        restrictedSettings.add(BASE_PATH_SETTING);
+        return restrictedSettings;
+    }
+
     @Override
     protected void doClose() {
         final Scheduler.Cancellable cancellable = finalizationFuture.getAndSet(null);
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RepositoryPlugin.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RepositoryPlugin.java
index 679243b28cfc7..a80ee0ca35fae 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RepositoryPlugin.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RepositoryPlugin.java
@@ -32,61 +32,131 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.util.json.Jackson;
-import org.opensearch.SpecialPermission;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
+import org.opensearch.env.NodeEnvironment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ReloadablePlugin;
 import org.opensearch.plugins.RepositoryPlugin;
+import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferEventLoopGroup;
+import org.opensearch.repositories.s3.async.AsyncTransferManager;
+import org.opensearch.script.ScriptService;
+import org.opensearch.threadpool.ExecutorBuilder;
+import org.opensearch.threadpool.FixedExecutorBuilder;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.watcher.ResourceWatcherService;
 
 import java.io.IOException;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
+import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.function.Supplier;
 
 /**
  * A plugin to add a repository type that writes to and from the AWS S3.
  */
 public class S3RepositoryPlugin extends Plugin implements RepositoryPlugin, ReloadablePlugin {
-
-    static {
-        SpecialPermission.check();
-        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
-            try {
-                // kick jackson to do some static caching of declared members info
-                Jackson.jsonNodeOf("{}");
-                // ClientConfiguration clinit has some classloader problems
-                // TODO: fix that
-                Class.forName("com.amazonaws.ClientConfiguration");
-            } catch (final ClassNotFoundException e) {
-                throw new RuntimeException(e);
-            }
-            return null;
-        });
-    }
+    private static final String PRIORITY_FUTURE_COMPLETION = "priority_future_completion";
+    private static final String PRIORITY_STREAM_READER = "priority_stream_reader";
+    private static final String FUTURE_COMPLETION = "future_completion";
+    private static final String STREAM_READER = "stream_reader";
 
     protected final S3Service service;
+    private final S3AsyncService s3AsyncService;
+
+    private final Path configPath;
+
+    private AsyncExecutorContainer priorityExecutorBuilder;
+    private AsyncExecutorContainer normalExecutorBuilder;
 
-    public S3RepositoryPlugin(final Settings settings) {
-        this(settings, new S3Service());
+    public S3RepositoryPlugin(final Settings settings, final Path configPath) {
+        this(settings, configPath, new S3Service(configPath), new S3AsyncService(configPath));
+    }
+
+    @Override
+    public List<ExecutorBuilder<?>> getExecutorBuilders(Settings settings) {
+        List<ExecutorBuilder<?>> executorBuilders = new ArrayList<>();
+        executorBuilders.add(
+            new FixedExecutorBuilder(settings, PRIORITY_FUTURE_COMPLETION, priorityPoolCount(settings), 10_000, PRIORITY_FUTURE_COMPLETION)
+        );
+        executorBuilders.add(
+            new FixedExecutorBuilder(settings, PRIORITY_STREAM_READER, priorityPoolCount(settings), 10_000, PRIORITY_STREAM_READER)
+        );
+        executorBuilders.add(new FixedExecutorBuilder(settings, FUTURE_COMPLETION, normalPoolCount(settings), 10_000, FUTURE_COMPLETION));
+        executorBuilders.add(new FixedExecutorBuilder(settings, STREAM_READER, normalPoolCount(settings), 10_000, STREAM_READER));
+        return executorBuilders;
     }
 
-    S3RepositoryPlugin(final Settings settings, final S3Service service) {
+    S3RepositoryPlugin(final Settings settings, final Path configPath, final S3Service service, final S3AsyncService s3AsyncService) {
         this.service = Objects.requireNonNull(service, "S3 service must not be null");
+        this.configPath = configPath;
         // eagerly load client settings so that secure settings are read
-        final Map<String, S3ClientSettings> clientsSettings = S3ClientSettings.load(settings);
+        Map<String, S3ClientSettings> clientsSettings = S3ClientSettings.load(settings, configPath);
+        this.s3AsyncService = Objects.requireNonNull(s3AsyncService, "S3AsyncService must not be null");
         this.service.refreshAndClearCache(clientsSettings);
+        this.s3AsyncService.refreshAndClearCache(clientsSettings);
+    }
+
+    private static int boundedBy(int value, int min, int max) {
+        return Math.min(max, Math.max(min, value));
+    }
+
+    private static int allocatedProcessors(Settings settings) {
+        return OpenSearchExecutors.allocatedProcessors(settings);
+    }
+
+    private static int priorityPoolCount(Settings settings) {
+        return boundedBy((allocatedProcessors(settings) + 1) / 2, 2, 4);
+    }
+
+    private static int normalPoolCount(Settings settings) {
+        return boundedBy((allocatedProcessors(settings) + 7) / 8, 1, 2);
+    }
+
+    @Override
+    public Collection<Object> createComponents(
+        final Client client,
+        final ClusterService clusterService,
+        final ThreadPool threadPool,
+        final ResourceWatcherService resourceWatcherService,
+        final ScriptService scriptService,
+        final NamedXContentRegistry xContentRegistry,
+        final Environment environment,
+        final NodeEnvironment nodeEnvironment,
+        final NamedWriteableRegistry namedWriteableRegistry,
+        final IndexNameExpressionResolver expressionResolver,
+        final Supplier<RepositoriesService> repositoriesServiceSupplier
+    ) {
+        int priorityEventLoopThreads = priorityPoolCount(clusterService.getSettings());
+        int normalEventLoopThreads = normalPoolCount(clusterService.getSettings());
+        this.priorityExecutorBuilder = new AsyncExecutorContainer(
+            threadPool.executor(PRIORITY_FUTURE_COMPLETION),
+            threadPool.executor(PRIORITY_STREAM_READER),
+            new AsyncTransferEventLoopGroup(priorityEventLoopThreads)
+        );
+        this.normalExecutorBuilder = new AsyncExecutorContainer(
+            threadPool.executor(FUTURE_COMPLETION),
+            threadPool.executor(STREAM_READER),
+            new AsyncTransferEventLoopGroup(normalEventLoopThreads)
+        );
+        return Collections.emptyList();
     }
 
     // proxy method for testing
@@ -96,7 +166,25 @@ protected S3Repository createRepository(
         final ClusterService clusterService,
         final RecoverySettings recoverySettings
     ) {
-        return new S3Repository(metadata, registry, service, clusterService, recoverySettings);
+
+        AsyncTransferManager asyncUploadUtils = new AsyncTransferManager(
+            S3Repository.PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING.get(clusterService.getSettings()).getBytes(),
+            normalExecutorBuilder.getStreamReader(),
+            priorityExecutorBuilder.getStreamReader()
+        );
+        return new S3Repository(
+            metadata,
+            registry,
+            service,
+            clusterService,
+            recoverySettings,
+            asyncUploadUtils,
+            priorityExecutorBuilder,
+            normalExecutorBuilder,
+            s3AsyncService,
+            S3Repository.PARALLEL_MULTIPART_UPLOAD_ENABLED_SETTING.get(clusterService.getSettings()),
+            configPath
+        );
     }
 
     @Override
@@ -121,6 +209,7 @@ public List<Setting<?>> getSettings() {
             S3ClientSettings.SESSION_TOKEN_SETTING,
             S3ClientSettings.ENDPOINT_SETTING,
             S3ClientSettings.PROTOCOL_SETTING,
+            S3ClientSettings.PROXY_TYPE_SETTING,
             S3ClientSettings.PROXY_HOST_SETTING,
             S3ClientSettings.PROXY_PORT_SETTING,
             S3ClientSettings.PROXY_USERNAME_SETTING,
@@ -132,19 +221,26 @@ public List<Setting<?>> getSettings() {
             S3Repository.ACCESS_KEY_SETTING,
             S3Repository.SECRET_KEY_SETTING,
             S3ClientSettings.SIGNER_OVERRIDE,
-            S3ClientSettings.REGION
+            S3ClientSettings.REGION,
+            S3ClientSettings.ROLE_ARN_SETTING,
+            S3ClientSettings.IDENTITY_TOKEN_FILE_SETTING,
+            S3ClientSettings.ROLE_SESSION_NAME_SETTING,
+            S3Repository.PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING,
+            S3Repository.PARALLEL_MULTIPART_UPLOAD_ENABLED_SETTING
         );
     }
 
     @Override
     public void reload(Settings settings) {
         // secure settings should be readable
-        final Map<String, S3ClientSettings> clientsSettings = S3ClientSettings.load(settings);
+        final Map<String, S3ClientSettings> clientsSettings = S3ClientSettings.load(settings, configPath);
         service.refreshAndClearCache(clientsSettings);
+        s3AsyncService.refreshAndClearCache(clientsSettings);
     }
 
     @Override
     public void close() throws IOException {
         service.close();
+        s3AsyncService.close();
     }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RetryingInputStream.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RetryingInputStream.java
index 388f5b8d74a2b..2c47dab386066 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RetryingInputStream.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RetryingInputStream.java
@@ -31,23 +31,25 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.services.s3.model.AmazonS3Exception;
-import com.amazonaws.services.s3.model.GetObjectRequest;
-import com.amazonaws.services.s3.model.ObjectMetadata;
-import com.amazonaws.services.s3.model.S3Object;
-import com.amazonaws.services.s3.model.S3ObjectInputStream;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.S3Exception;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.repositories.s3.utils.HttpRangeUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * Wrapper around an S3 object that will retry the {@link GetObjectRequest} if the download fails part-way through, resuming from where
@@ -69,7 +71,8 @@ class S3RetryingInputStream extends InputStream {
     private final int maxAttempts;
     private final List<IOException> failures;
 
-    private S3ObjectInputStream currentStream;
+    private ResponseInputStream<GetObjectResponse> currentStream;
+    private final AtomicBoolean isStreamAborted = new AtomicBoolean();
     private long currentStreamLastOffset;
     private int attempt = 1;
     private long currentOffset;
@@ -99,8 +102,10 @@ class S3RetryingInputStream extends InputStream {
 
     private void openStream() throws IOException {
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            final GetObjectRequest getObjectRequest = new GetObjectRequest(blobStore.bucket(), blobKey);
-            getObjectRequest.setRequestMetricCollector(blobStore.getMetricCollector);
+            final GetObjectRequest.Builder getObjectRequest = GetObjectRequest.builder()
+                .bucket(blobStore.bucket())
+                .key(blobKey)
+                .overrideConfiguration(o -> o.addMetricPublisher(blobStore.getStatsMetricPublisher().getObjectMetricPublisher));
             if (currentOffset > 0 || start > 0 || end < Long.MAX_VALUE - 1) {
                 assert start + currentOffset <= end : "requesting beyond end, start = "
                     + start
@@ -108,14 +113,20 @@ private void openStream() throws IOException {
                     + currentOffset
                     + " end="
                     + end;
-                getObjectRequest.setRange(Math.addExact(start, currentOffset), end);
+                getObjectRequest.range(HttpRangeUtils.toHttpRangeHeader(Math.addExact(start, currentOffset), end));
             }
-            final S3Object s3Object = SocketAccess.doPrivileged(() -> clientReference.get().getObject(getObjectRequest));
-            this.currentStreamLastOffset = Math.addExact(Math.addExact(start, currentOffset), getStreamLength(s3Object));
-            this.currentStream = s3Object.getObjectContent();
-        } catch (final AmazonClientException e) {
-            if (e instanceof AmazonS3Exception) {
-                if (404 == ((AmazonS3Exception) e).getStatusCode()) {
+            final ResponseInputStream<GetObjectResponse> getObjectResponseInputStream = SocketAccess.doPrivileged(
+                () -> clientReference.get().getObject(getObjectRequest.build())
+            );
+            this.currentStreamLastOffset = Math.addExact(
+                Math.addExact(start, currentOffset),
+                getObjectResponseInputStream.response().contentLength()
+            );
+            this.currentStream = getObjectResponseInputStream;
+            this.isStreamAborted.set(false);
+        } catch (final SdkException e) {
+            if (e instanceof S3Exception) {
+                if (404 == ((S3Exception) e).statusCode()) {
                     throw addSuppressedExceptions(new NoSuchFileException("Blob object [" + blobKey + "] not found: " + e.getMessage()));
                 }
             }
@@ -123,30 +134,6 @@ private void openStream() throws IOException {
         }
     }
 
-    private long getStreamLength(final S3Object object) {
-        final ObjectMetadata metadata = object.getObjectMetadata();
-        try {
-            // Returns the content range of the object if response contains the Content-Range header.
-            final Long[] range = metadata.getContentRange();
-            if (range != null) {
-                assert range[1] >= range[0] : range[1] + " vs " + range[0];
-                assert range[0] == start + currentOffset : "Content-Range start value ["
-                    + range[0]
-                    + "] exceeds start ["
-                    + start
-                    + "] + current offset ["
-                    + currentOffset
-                    + ']';
-                assert range[1] == end : "Content-Range end value [" + range[1] + "] exceeds end [" + end + ']';
-                return range[1] - range[0] + 1L;
-            }
-            return metadata.getContentLength();
-        } catch (Exception e) {
-            assert false : e;
-            return Long.MAX_VALUE - 1L; // assume a large stream so that the underlying stream is aborted on closing, unless eof is reached
-        }
-    }
-
     @Override
     public int read() throws IOException {
         ensureOpen();
@@ -236,16 +223,17 @@ public void close() throws IOException {
     }
 
     /**
-     * Abort the {@link S3ObjectInputStream} if it wasn't read completely at the time this method is called,
+     * Abort the {@link ResponseInputStream} if it wasn't read completely at the time this method is called,
      * suppressing all thrown exceptions.
      */
-    private void maybeAbort(S3ObjectInputStream stream) {
-        if (isEof()) {
+    private void maybeAbort(ResponseInputStream<GetObjectResponse> stream) {
+        if (isEof() || isAborted()) {
             return;
         }
         try {
             if (start + currentOffset < currentStreamLastOffset) {
                 stream.abort();
+                isStreamAborted.compareAndSet(false, true);
             }
         } catch (Exception e) {
             logger.warn("Failed to abort stream before closing", e);
@@ -276,9 +264,6 @@ boolean isEof() {
 
     // package-private for tests
     boolean isAborted() {
-        if (currentStream == null || currentStream.getHttpRequest() == null) {
-            return false;
-        }
-        return currentStream.getHttpRequest().isAborted();
+        return isStreamAborted.get();
     }
 }
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Service.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Service.java
index 3ce19378ac05c..b1b3e19eac275 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Service.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3Service.java
@@ -32,19 +32,31 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
-import com.amazonaws.auth.EC2ContainerCredentialsProviderWrapper;
-import com.amazonaws.client.builder.AwsClientBuilder;
-import com.amazonaws.http.IdleConnectionReaper;
-import com.amazonaws.http.SystemPropertyTlsKeyManagersProvider;
-import com.amazonaws.http.conn.ssl.SdkTLSSocketFactory;
-import com.amazonaws.internal.SdkSSLContext;
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.s3.AmazonS3ClientBuilder;
-import com.amazonaws.services.s3.internal.Constants;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.ContainerCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.InstanceProfileCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.SdkSystemSetting;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.client.config.SdkAdvancedClientOption;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.retry.RetryPolicy;
+import software.amazon.awssdk.core.retry.backoff.BackoffStrategy;
+import software.amazon.awssdk.http.SystemPropertyTlsKeyManagersProvider;
+import software.amazon.awssdk.http.apache.ApacheHttpClient;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+import software.amazon.awssdk.http.apache.internal.conn.SdkTlsSocketFactory;
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.S3ClientBuilder;
+import software.amazon.awssdk.services.sts.StsClient;
+import software.amazon.awssdk.services.sts.StsClientBuilder;
+import software.amazon.awssdk.services.sts.auth.StsAssumeRoleCredentialsProvider;
+import software.amazon.awssdk.services.sts.auth.StsWebIdentityTokenFileCredentialsProvider;
+import software.amazon.awssdk.services.sts.model.AssumeRoleRequest;
 
 import org.apache.http.conn.ssl.DefaultHostnameVerifier;
 import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
@@ -52,11 +64,17 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-import org.opensearch.common.Strings;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.repositories.s3.S3ClientSettings.IrsaCredentials;
+import org.opensearch.repositories.s3.utils.AwsRequestSigner;
+import org.opensearch.repositories.s3.utils.Protocol;
 
 import javax.net.ssl.SSLContext;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.net.Authenticator;
@@ -64,28 +82,43 @@
 import java.net.PasswordAuthentication;
 import java.net.Proxy;
 import java.net.Socket;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.time.Duration;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import static java.util.Collections.emptyMap;
 
 class S3Service implements Closeable {
     private static final Logger logger = LogManager.getLogger(S3Service.class);
 
-    private volatile Map<S3ClientSettings, AmazonS3Reference> clientsCache = emptyMap();
+    private static final String STS_ENDPOINT_OVERRIDE_SYSTEM_PROPERTY = "aws.stsEndpointOverride";
+
+    private static final String DEFAULT_S3_ENDPOINT = "s3.amazonaws.com";
+
+    private volatile Map<S3ClientSettings, AmazonS3Reference> clientsCache = new ConcurrentHashMap<>();
 
     /**
      * Client settings calculated from static configuration and settings in the keystore.
      */
-    private volatile Map<String, S3ClientSettings> staticClientSettings = MapBuilder.<String, S3ClientSettings>newMapBuilder()
-        .put("default", S3ClientSettings.getClientSettings(Settings.EMPTY, "default"))
-        .immutableMap();
+    private volatile Map<String, S3ClientSettings> staticClientSettings;
 
     /**
      * Client settings derived from those in {@link #staticClientSettings} by combining them with settings
      * in the {@link RepositoryMetadata}.
      */
-    private volatile Map<Settings, S3ClientSettings> derivedClientSettings = emptyMap();
+    private volatile Map<Settings, S3ClientSettings> derivedClientSettings = new ConcurrentHashMap<>();
+
+    S3Service(final Path configPath) {
+        staticClientSettings = MapBuilder.<String, S3ClientSettings>newMapBuilder()
+            .put("default", S3ClientSettings.getClientSettings(Settings.EMPTY, "default", configPath))
+            .immutableMap();
+    }
 
     /**
      * Refreshes the settings for the AmazonS3 clients and clears the cache of
@@ -163,19 +196,22 @@ S3ClientSettings settings(RepositoryMetadata repositoryMetadata) {
     }
 
     // proxy for testing
-    AmazonS3 buildClient(final S3ClientSettings clientSettings) {
-        final AmazonS3ClientBuilder builder = AmazonS3ClientBuilder.standard();
-        builder.withCredentials(buildCredentials(logger, clientSettings));
-        builder.withClientConfiguration(buildConfiguration(clientSettings));
+    AmazonS3WithCredentials buildClient(final S3ClientSettings clientSettings) {
+        setDefaultAwsProfilePath();
+        final S3ClientBuilder builder = S3Client.builder();
 
-        String endpoint = Strings.hasLength(clientSettings.endpoint) ? clientSettings.endpoint : Constants.S3_HOSTNAME;
+        final AwsCredentialsProvider credentials = buildCredentials(logger, clientSettings);
+        builder.credentialsProvider(credentials);
+        builder.httpClientBuilder(buildHttpClient(clientSettings));
+        builder.overrideConfiguration(buildOverrideConfiguration(clientSettings));
+
+        String endpoint = Strings.hasLength(clientSettings.endpoint) ? clientSettings.endpoint : DEFAULT_S3_ENDPOINT;
         if ((endpoint.startsWith("http://") || endpoint.startsWith("https://")) == false) {
             // Manually add the schema to the endpoint to work around https://github.com/aws/aws-sdk-java/issues/2274
             // TODO: Remove this once fixed in the AWS SDK
             endpoint = clientSettings.protocol.toString() + "://" + endpoint;
         }
-        final String region = Strings.hasLength(clientSettings.region) ? clientSettings.region : null;
-        logger.debug("using endpoint [{}] and region [{}]", endpoint, region);
+        logger.debug("using endpoint [{}] and region [{}]", endpoint, clientSettings.region);
 
         // If the endpoint configuration isn't set on the builder then the default behaviour is to try
         // and work out what region we are in and use an appropriate endpoint - see AwsClientBuilder#setRegion.
@@ -185,25 +221,43 @@ AmazonS3 buildClient(final S3ClientSettings clientSettings) {
         //
         // We do this because directly constructing the client is deprecated (was already deprecated in 1.1.223 too)
         // so this change removes that usage of a deprecated API.
-        builder.withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint, region));
+        builder.endpointOverride(URI.create(endpoint));
+        if (Strings.hasText(clientSettings.region)) {
+            builder.region(Region.of(clientSettings.region));
+        }
         if (clientSettings.pathStyleAccess) {
-            builder.enablePathStyleAccess();
+            builder.forcePathStyle(true);
         }
         if (clientSettings.disableChunkedEncoding) {
-            builder.disableChunkedEncoding();
+            builder.serviceConfiguration(s -> s.chunkedEncodingEnabled(false));
         }
-        return SocketAccess.doPrivileged(builder::build);
+        final S3Client client = SocketAccess.doPrivileged(builder::build);
+        return AmazonS3WithCredentials.create(client, credentials);
     }
 
-    // pkg private for tests
-    static ClientConfiguration buildConfiguration(S3ClientSettings clientSettings) {
-        final ClientConfiguration clientConfiguration = new ClientConfiguration();
-        // the response metadata cache is only there for diagnostics purposes,
-        // but can force objects from every response to the old generation.
-        clientConfiguration.setResponseMetadataCacheSize(0);
-        clientConfiguration.setProtocol(clientSettings.protocol);
-
-        if (clientSettings.proxySettings != ProxySettings.NO_PROXY_SETTINGS) {
+    // Aws v2 sdk tries to load a default profile from home path which is restricted. Hence, setting these to random
+    // valid paths.
+    @SuppressForbidden(reason = "Need to provide this override to v2 SDK so that path does not default to home path")
+    static void setDefaultAwsProfilePath() {
+        if (ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.getStringValue().isEmpty()) {
+            SocketAccess.doPrivileged(
+                () -> System.setProperty(
+                    ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(),
+                    System.getProperty("opensearch.path.conf")
+                )
+            );
+        }
+        if (ProfileFileSystemSetting.AWS_CONFIG_FILE.getStringValue().isEmpty()) {
+            SocketAccess.doPrivileged(
+                () -> System.setProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), System.getProperty("opensearch.path.conf"))
+            );
+        }
+    }
+
+    static ApacheHttpClient.Builder buildHttpClient(S3ClientSettings clientSettings) {
+        ApacheHttpClient.Builder clientBuilder = ApacheHttpClient.builder();
+
+        if (!clientSettings.proxySettings.equals(ProxySettings.NO_PROXY_SETTINGS)) {
             if (clientSettings.proxySettings.getType() == ProxySettings.ProxyType.SOCKS) {
                 SocketAccess.doPrivilegedVoid(() -> {
                     if (clientSettings.proxySettings.isAuthenticated()) {
@@ -217,86 +271,233 @@ protected PasswordAuthentication getPasswordAuthentication() {
                             }
                         });
                     }
-                    clientConfiguration.getApacheHttpClientConfig()
-                        .setSslSocketFactory(createSocksSslConnectionSocketFactory(clientSettings.proxySettings.getAddress()));
+                    clientBuilder.socketFactory(createSocksSslConnectionSocketFactory(clientSettings.proxySettings.getAddress()));
                 });
             } else {
-                if (clientSettings.proxySettings.getType() != ProxySettings.ProxyType.DIRECT) {
-                    clientConfiguration.setProxyProtocol(clientSettings.proxySettings.getType().toProtocol());
-                }
-                clientConfiguration.setProxyHost(clientSettings.proxySettings.getHostName());
-                clientConfiguration.setProxyPort(clientSettings.proxySettings.getPort());
-                clientConfiguration.setProxyUsername(clientSettings.proxySettings.getUsername());
-                clientConfiguration.setProxyPassword(clientSettings.proxySettings.getPassword());
+                clientBuilder.proxyConfiguration(buildHttpProxyConfiguration(clientSettings));
             }
         }
 
-        if (Strings.hasLength(clientSettings.signerOverride)) {
-            clientConfiguration.setSignerOverride(clientSettings.signerOverride);
+        clientBuilder.socketTimeout(Duration.ofMillis(clientSettings.readTimeoutMillis));
+
+        return clientBuilder;
+    }
+
+    static ProxyConfiguration buildHttpProxyConfiguration(S3ClientSettings clientSettings) {
+        ProxyConfiguration.Builder proxyConfiguration = ProxyConfiguration.builder();
+        if (clientSettings.proxySettings.getType() == ProxySettings.ProxyType.SOCKS) {
+            return proxyConfiguration.build();
         }
 
-        clientConfiguration.setMaxErrorRetry(clientSettings.maxRetries);
-        clientConfiguration.setUseThrottleRetries(clientSettings.throttleRetries);
-        clientConfiguration.setSocketTimeout(clientSettings.readTimeoutMillis);
+        Protocol proxyProtocol = clientSettings.proxySettings.getType() == ProxySettings.ProxyType.DIRECT
+            ? Protocol.HTTP
+            : clientSettings.proxySettings.getType().toProtocol();
 
-        return clientConfiguration;
+        try {
+            proxyConfiguration = proxyConfiguration.endpoint(
+                new URI(
+                    proxyProtocol.toString(),
+                    null,
+                    clientSettings.proxySettings.getHost(),
+                    clientSettings.proxySettings.getPort(),
+                    null,
+                    null,
+                    null
+                )
+            );
+        } catch (URISyntaxException e) {
+            throw SdkException.create("Invalid proxy URL", e);
+        }
+
+        proxyConfiguration = proxyConfiguration.username(clientSettings.proxySettings.getUsername());
+        proxyConfiguration = proxyConfiguration.password(clientSettings.proxySettings.getPassword());
+
+        return proxyConfiguration.build();
+    }
+
+    static ClientOverrideConfiguration buildOverrideConfiguration(final S3ClientSettings clientSettings) {
+        ClientOverrideConfiguration.Builder clientOverrideConfiguration = ClientOverrideConfiguration.builder();
+        if (Strings.hasLength(clientSettings.signerOverride)) {
+            clientOverrideConfiguration = clientOverrideConfiguration.putAdvancedOption(
+                SdkAdvancedClientOption.SIGNER,
+                AwsRequestSigner.fromSignerName(clientSettings.signerOverride).getSigner()
+            );
+        }
+        RetryPolicy.Builder retryPolicy = SocketAccess.doPrivileged(
+            () -> RetryPolicy.builder().numRetries(clientSettings.maxRetries).retryCapacityCondition(null)
+        );
+        if (!clientSettings.throttleRetries) {
+            retryPolicy.throttlingBackoffStrategy(BackoffStrategy.none());
+        }
+        return clientOverrideConfiguration.retryPolicy(retryPolicy.build()).build();
     }
 
     private static SSLConnectionSocketFactory createSocksSslConnectionSocketFactory(final InetSocketAddress address) {
         // This part was taken from AWS settings
-        final SSLContext sslCtx = SdkSSLContext.getPreferredSSLContext(
-            new SystemPropertyTlsKeyManagersProvider().getKeyManagers(),
-            new SecureRandom()
-        );
-        return new SdkTLSSocketFactory(sslCtx, new DefaultHostnameVerifier()) {
-            @Override
-            public Socket createSocket(final HttpContext ctx) throws IOException {
-                return new Socket(new Proxy(Proxy.Type.SOCKS, address));
-            }
-        };
+        try {
+            final SSLContext sslCtx = SSLContext.getInstance("TLS");
+            sslCtx.init(SystemPropertyTlsKeyManagersProvider.create().keyManagers(), null, new SecureRandom());
+            return new SdkTlsSocketFactory(sslCtx, new DefaultHostnameVerifier()) {
+                @Override
+                public Socket createSocket(final HttpContext ctx) throws IOException {
+                    return new Socket(new Proxy(Proxy.Type.SOCKS, address));
+                }
+            };
+        } catch (NoSuchAlgorithmException | KeyManagementException e) {
+            throw SdkException.create("Exception during SSL context creation for SOCKS proxy", e);
+        }
     }
 
     // pkg private for tests
-    static AWSCredentialsProvider buildCredentials(Logger logger, S3ClientSettings clientSettings) {
-        final S3BasicCredentials credentials = clientSettings.credentials;
-        if (credentials == null) {
+    static AwsCredentialsProvider buildCredentials(Logger logger, S3ClientSettings clientSettings) {
+        final AwsCredentials basicCredentials = clientSettings.credentials;
+        final IrsaCredentials irsaCredentials = buildFromEnviroment(clientSettings.irsaCredentials);
+
+        // If IAM Roles for Service Accounts (IRSA) credentials are configured, start with them first
+        if (irsaCredentials != null) {
+            logger.debug("Using IRSA credentials");
+
+            StsClient stsClient = SocketAccess.doPrivileged(() -> {
+                StsClientBuilder builder = StsClient.builder();
+                if (Strings.hasText(clientSettings.region)) {
+                    builder.region(Region.of(clientSettings.region));
+                }
+
+                final String stsEndpoint = System.getProperty(STS_ENDPOINT_OVERRIDE_SYSTEM_PROPERTY);
+                if (stsEndpoint != null) {
+                    builder = builder.endpointOverride(URI.create(stsEndpoint));
+                }
+
+                if (basicCredentials != null) {
+                    builder = builder.credentialsProvider(StaticCredentialsProvider.create(basicCredentials));
+                } else {
+                    builder = builder.credentialsProvider(DefaultCredentialsProvider.create());
+                }
+
+                return builder.build();
+            });
+
+            if (irsaCredentials.getIdentityTokenFile() == null) {
+                final StsAssumeRoleCredentialsProvider.Builder stsCredentialsProviderBuilder = StsAssumeRoleCredentialsProvider.builder()
+                    .stsClient(stsClient)
+                    .refreshRequest(
+                        AssumeRoleRequest.builder()
+                            .roleArn(irsaCredentials.getRoleArn())
+                            .roleSessionName(irsaCredentials.getRoleSessionName())
+                            .build()
+                    );
+
+                final StsAssumeRoleCredentialsProvider stsCredentialsProvider = SocketAccess.doPrivileged(
+                    stsCredentialsProviderBuilder::build
+                );
+
+                return new PrivilegedSTSAssumeRoleSessionCredentialsProvider<>(stsClient, stsCredentialsProvider);
+            } else {
+                final StsWebIdentityTokenFileCredentialsProvider.Builder stsCredentialsProviderBuilder =
+                    StsWebIdentityTokenFileCredentialsProvider.builder()
+                        .stsClient(stsClient)
+                        .roleArn(irsaCredentials.getRoleArn())
+                        .roleSessionName(irsaCredentials.getRoleSessionName())
+                        .webIdentityTokenFile(Path.of(irsaCredentials.getIdentityTokenFile()));
+
+                final StsWebIdentityTokenFileCredentialsProvider stsCredentialsProvider = SocketAccess.doPrivileged(
+                    stsCredentialsProviderBuilder::build
+                );
+
+                return new PrivilegedSTSAssumeRoleSessionCredentialsProvider<>(stsClient, stsCredentialsProvider);
+            }
+        } else if (basicCredentials != null) {
+            logger.debug("Using basic key/secret credentials");
+            return StaticCredentialsProvider.create(basicCredentials);
+        } else {
             logger.debug("Using instance profile credentials");
             return new PrivilegedInstanceProfileCredentialsProvider();
-        } else {
-            logger.debug("Using basic key/secret credentials");
-            return new AWSStaticCredentialsProvider(credentials);
         }
     }
 
+    private static IrsaCredentials buildFromEnviroment(IrsaCredentials defaults) {
+        if (defaults == null) {
+            return null;
+        }
+
+        String webIdentityTokenFile = defaults.getIdentityTokenFile();
+        if (webIdentityTokenFile == null) {
+            webIdentityTokenFile = System.getenv(SdkSystemSetting.AWS_WEB_IDENTITY_TOKEN_FILE.environmentVariable());
+        }
+
+        String roleArn = defaults.getRoleArn();
+        if (roleArn == null) {
+            roleArn = System.getenv(SdkSystemSetting.AWS_ROLE_ARN.environmentVariable());
+        }
+
+        String roleSessionName = defaults.getRoleSessionName();
+        if (roleSessionName == null) {
+            roleSessionName = System.getenv(SdkSystemSetting.AWS_ROLE_SESSION_NAME.environmentVariable());
+        }
+
+        return new IrsaCredentials(webIdentityTokenFile, roleArn, roleSessionName);
+    }
+
     private synchronized void releaseCachedClients() {
         // the clients will shutdown when they will not be used anymore
         for (final AmazonS3Reference clientReference : clientsCache.values()) {
             clientReference.decRef();
         }
+
         // clear previously cached clients, they will be build lazily
         clientsCache = emptyMap();
         derivedClientSettings = emptyMap();
-        // shutdown IdleConnectionReaper background thread
-        // it will be restarted on new client usage
-        IdleConnectionReaper.shutdown();
     }
 
-    static class PrivilegedInstanceProfileCredentialsProvider implements AWSCredentialsProvider {
-        private final AWSCredentialsProvider credentials;
+    static class PrivilegedInstanceProfileCredentialsProvider implements AwsCredentialsProvider {
+        private final AwsCredentialsProvider credentials;
 
         private PrivilegedInstanceProfileCredentialsProvider() {
+            this.credentials = initializeProvider();
+        }
+
+        private AwsCredentialsProvider initializeProvider() {
+            if (SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI.getStringValue().isPresent()
+                || SdkSystemSetting.AWS_CONTAINER_CREDENTIALS_FULL_URI.getStringValue().isPresent()) {
+
+                return ContainerCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
+            }
             // InstanceProfileCredentialsProvider as last item of chain
-            this.credentials = new EC2ContainerCredentialsProviderWrapper();
+            return InstanceProfileCredentialsProvider.builder().asyncCredentialUpdateEnabled(true).build();
         }
 
         @Override
-        public AWSCredentials getCredentials() {
-            return SocketAccess.doPrivileged(credentials::getCredentials);
+        public AwsCredentials resolveCredentials() {
+            return SocketAccess.doPrivileged(credentials::resolveCredentials);
+        }
+    }
+
+    static class PrivilegedSTSAssumeRoleSessionCredentialsProvider<P extends AwsCredentialsProvider & AutoCloseable>
+        implements
+            AwsCredentialsProvider,
+            Closeable {
+        private final P credentials;
+        private final StsClient stsClient;
+
+        private PrivilegedSTSAssumeRoleSessionCredentialsProvider(@Nullable final StsClient stsClient, final P credentials) {
+            this.stsClient = stsClient;
+            this.credentials = credentials;
+        }
+
+        @Override
+        public void close() throws IOException {
+            SocketAccess.doPrivilegedIOException(() -> {
+                credentials.close();
+                if (stsClient != null) {
+                    stsClient.close();
+                }
+                return null;
+            });
         }
 
         @Override
-        public void refresh() {
-            SocketAccess.doPrivilegedVoid(credentials::refresh);
+        public AwsCredentials resolveCredentials() {
+            return SocketAccess.doPrivileged(credentials::resolveCredentials);
         }
     }
 
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/SocketAccess.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/SocketAccess.java
index 0a6408764aeeb..4888764dbc720 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/SocketAccess.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/SocketAccess.java
@@ -46,7 +46,7 @@
  * {@link SocketPermission} 'connect' to establish connections. This class wraps the operations requiring access in
  * {@link AccessController#doPrivileged(PrivilegedAction)} blocks.
  */
-final class SocketAccess {
+public final class SocketAccess {
 
     private SocketAccess() {}
 
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/StatsMetricPublisher.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/StatsMetricPublisher.java
new file mode 100644
index 0000000000000..cad0037f99249
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/StatsMetricPublisher.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.http.HttpMetric;
+import software.amazon.awssdk.metrics.MetricCollection;
+import software.amazon.awssdk.metrics.MetricPublisher;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class StatsMetricPublisher {
+
+    private final Stats stats = new Stats();
+
+    public MetricPublisher listObjectsMetricPublisher = new MetricPublisher() {
+        @Override
+        public void publish(MetricCollection metricCollection) {
+            stats.listCount.addAndGet(
+                metricCollection.children()
+                    .stream()
+                    .filter(
+                        metricRecords -> metricRecords.name().equals("ApiCallAttempt")
+                            && !metricRecords.metricValues(HttpMetric.HTTP_STATUS_CODE).isEmpty()
+                    )
+                    .count()
+            );
+        }
+
+        @Override
+        public void close() {}
+    };
+
+    public MetricPublisher getObjectMetricPublisher = new MetricPublisher() {
+        @Override
+        public void publish(MetricCollection metricCollection) {
+            stats.getCount.addAndGet(
+                metricCollection.children()
+                    .stream()
+                    .filter(
+                        metricRecords -> metricRecords.name().equals("ApiCallAttempt")
+                            && !metricRecords.metricValues(HttpMetric.HTTP_STATUS_CODE).isEmpty()
+                    )
+                    .count()
+            );
+        }
+
+        @Override
+        public void close() {}
+    };
+
+    public MetricPublisher putObjectMetricPublisher = new MetricPublisher() {
+        @Override
+        public void publish(MetricCollection metricCollection) {
+            stats.putCount.addAndGet(
+                metricCollection.children()
+                    .stream()
+                    .filter(
+                        metricRecords -> metricRecords.name().equals("ApiCallAttempt")
+                            && !metricRecords.metricValues(HttpMetric.HTTP_STATUS_CODE).isEmpty()
+                    )
+                    .count()
+            );
+        }
+
+        @Override
+        public void close() {}
+    };
+
+    public MetricPublisher multipartUploadMetricCollector = new MetricPublisher() {
+        @Override
+        public void publish(MetricCollection metricCollection) {
+            stats.postCount.addAndGet(
+                metricCollection.children()
+                    .stream()
+                    .filter(
+                        metricRecords -> metricRecords.name().equals("ApiCallAttempt")
+                            && !metricRecords.metricValues(HttpMetric.HTTP_STATUS_CODE).isEmpty()
+                    )
+                    .count()
+            );
+        }
+
+        @Override
+        public void close() {}
+    };
+
+    public Stats getStats() {
+        return stats;
+    }
+
+    static class Stats {
+
+        final AtomicLong listCount = new AtomicLong();
+
+        final AtomicLong getCount = new AtomicLong();
+
+        final AtomicLong putCount = new AtomicLong();
+
+        final AtomicLong postCount = new AtomicLong();
+
+        Map<String, Long> toMap() {
+            final Map<String, Long> results = new HashMap<>();
+            results.put("GetObject", getCount.get());
+            results.put("ListObjects", listCount.get());
+            results.put("PutObject", putCount.get());
+            results.put("PutMultipartObject", postCount.get());
+            return results;
+        }
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncExecutorContainer.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncExecutorContainer.java
new file mode 100644
index 0000000000000..1ae1a15ad4010
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncExecutorContainer.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import java.util.concurrent.ExecutorService;
+
+/**
+ * An encapsulation for the {@link AsyncTransferEventLoopGroup}, and the stream reader and future completion executor services
+ */
+public class AsyncExecutorContainer {
+
+    private final ExecutorService futureCompletionExecutor;
+    private final ExecutorService streamReader;
+    private final AsyncTransferEventLoopGroup asyncTransferEventLoopGroup;
+
+    /**
+     * Construct a new AsyncExecutorBuilder object
+     *
+     * @param futureCompletionExecutor An {@link ExecutorService} to pass to {@link software.amazon.awssdk.services.s3.S3AsyncClient} for future completion
+     * @param streamReader An {@link ExecutorService} to read streams for upload
+     * @param asyncTransferEventLoopGroup A {@link AsyncTransferEventLoopGroup} which encapsulates the netty {@link io.netty.channel.EventLoopGroup} for async uploads
+     */
+    public AsyncExecutorContainer(
+        ExecutorService futureCompletionExecutor,
+        ExecutorService streamReader,
+        AsyncTransferEventLoopGroup asyncTransferEventLoopGroup
+    ) {
+        this.asyncTransferEventLoopGroup = asyncTransferEventLoopGroup;
+        this.streamReader = streamReader;
+        this.futureCompletionExecutor = futureCompletionExecutor;
+    }
+
+    public ExecutorService getFutureCompletionExecutor() {
+        return futureCompletionExecutor;
+    }
+
+    public AsyncTransferEventLoopGroup getAsyncTransferEventLoopGroup() {
+        return asyncTransferEventLoopGroup;
+    }
+
+    public ExecutorService getStreamReader() {
+        return streamReader;
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncPartsHandler.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncPartsHandler.java
new file mode 100644
index 0000000000000..ad6939ce299d6
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncPartsHandler.java
@@ -0,0 +1,184 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import software.amazon.awssdk.core.async.AsyncRequestBody;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.ChecksumAlgorithm;
+import software.amazon.awssdk.services.s3.model.CompletedPart;
+import software.amazon.awssdk.services.s3.model.UploadPartRequest;
+import software.amazon.awssdk.services.s3.model.UploadPartResponse;
+import software.amazon.awssdk.utils.CompletableFutureUtils;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.repositories.s3.SocketAccess;
+import org.opensearch.repositories.s3.io.CheckedContainer;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicReferenceArray;
+
+/**
+ * Responsible for handling parts of the original multipart request
+ */
+public class AsyncPartsHandler {
+
+    private static Logger log = LogManager.getLogger(AsyncPartsHandler.class);
+
+    /**
+     * Uploads parts of the upload multipart request*
+     * @param s3AsyncClient S3 client to use for upload
+     * @param executorService Thread pool for regular upload
+     * @param priorityExecutorService Thread pool for priority uploads
+     * @param uploadRequest request for upload
+     * @param streamContext Stream context used in supplying individual file parts
+     * @param uploadId Upload Id against which multi-part is being performed
+     * @param completedParts Reference of completed parts
+     * @param inputStreamContainers Checksum containers
+     * @return list of completable futures
+     * @throws IOException thrown in case of an IO error
+     */
+    public static List<CompletableFuture<CompletedPart>> uploadParts(
+        S3AsyncClient s3AsyncClient,
+        ExecutorService executorService,
+        ExecutorService priorityExecutorService,
+        UploadRequest uploadRequest,
+        StreamContext streamContext,
+        String uploadId,
+        AtomicReferenceArray<CompletedPart> completedParts,
+        AtomicReferenceArray<CheckedContainer> inputStreamContainers
+    ) throws IOException {
+        List<CompletableFuture<CompletedPart>> futures = new ArrayList<>();
+        for (int partIdx = 0; partIdx < streamContext.getNumberOfParts(); partIdx++) {
+            InputStreamContainer inputStreamContainer = streamContext.provideStream(partIdx);
+            inputStreamContainers.set(partIdx, new CheckedContainer(inputStreamContainer.getContentLength()));
+            UploadPartRequest.Builder uploadPartRequestBuilder = UploadPartRequest.builder()
+                .bucket(uploadRequest.getBucket())
+                .partNumber(partIdx + 1)
+                .key(uploadRequest.getKey())
+                .uploadId(uploadId)
+                .contentLength(inputStreamContainer.getContentLength());
+            if (uploadRequest.doRemoteDataIntegrityCheck()) {
+                uploadPartRequestBuilder.checksumAlgorithm(ChecksumAlgorithm.CRC32);
+            }
+            uploadPart(
+                s3AsyncClient,
+                executorService,
+                priorityExecutorService,
+                completedParts,
+                inputStreamContainers,
+                futures,
+                uploadPartRequestBuilder.build(),
+                inputStreamContainer,
+                uploadRequest
+            );
+        }
+
+        return futures;
+    }
+
+    /**
+     * Cleans up parts of the original multipart request*
+     * @param s3AsyncClient s3 client to use
+     * @param uploadRequest upload request
+     * @param uploadId upload id against which multi-part was carried out.
+     */
+    public static void cleanUpParts(S3AsyncClient s3AsyncClient, UploadRequest uploadRequest, String uploadId) {
+
+        AbortMultipartUploadRequest abortMultipartUploadRequest = AbortMultipartUploadRequest.builder()
+            .bucket(uploadRequest.getBucket())
+            .key(uploadRequest.getKey())
+            .uploadId(uploadId)
+            .build();
+        SocketAccess.doPrivileged(() -> s3AsyncClient.abortMultipartUpload(abortMultipartUploadRequest).exceptionally(throwable -> {
+            log.warn(
+                () -> new ParameterizedMessage(
+                    "Failed to abort previous multipart upload "
+                        + "(id: {})"
+                        + ". You may need to call "
+                        + "S3AsyncClient#abortMultiPartUpload to "
+                        + "free all storage consumed by"
+                        + " all parts. ",
+                    uploadId
+                ),
+                throwable
+            );
+            return null;
+        }));
+    }
+
+    private static void uploadPart(
+        S3AsyncClient s3AsyncClient,
+        ExecutorService executorService,
+        ExecutorService priorityExecutorService,
+        AtomicReferenceArray<CompletedPart> completedParts,
+        AtomicReferenceArray<CheckedContainer> inputStreamContainers,
+        List<CompletableFuture<CompletedPart>> futures,
+        UploadPartRequest uploadPartRequest,
+        InputStreamContainer inputStreamContainer,
+        UploadRequest uploadRequest
+    ) {
+        Integer partNumber = uploadPartRequest.partNumber();
+
+        ExecutorService streamReadExecutor = uploadRequest.getWritePriority() == WritePriority.HIGH
+            ? priorityExecutorService
+            : executorService;
+        CompletableFuture<UploadPartResponse> uploadPartResponseFuture = SocketAccess.doPrivileged(
+            () -> s3AsyncClient.uploadPart(
+                uploadPartRequest,
+                AsyncRequestBody.fromInputStream(
+                    inputStreamContainer.getInputStream(),
+                    inputStreamContainer.getContentLength(),
+                    streamReadExecutor
+                )
+            )
+        );
+
+        CompletableFuture<CompletedPart> convertFuture = uploadPartResponseFuture.thenApply(
+            uploadPartResponse -> convertUploadPartResponse(
+                completedParts,
+                inputStreamContainers,
+                uploadPartResponse,
+                partNumber,
+                uploadRequest.doRemoteDataIntegrityCheck()
+            )
+        );
+        futures.add(convertFuture);
+
+        CompletableFutureUtils.forwardExceptionTo(convertFuture, uploadPartResponseFuture);
+    }
+
+    private static CompletedPart convertUploadPartResponse(
+        AtomicReferenceArray<CompletedPart> completedParts,
+        AtomicReferenceArray<CheckedContainer> inputStreamContainers,
+        UploadPartResponse partResponse,
+        int partNumber,
+        boolean isRemoteDataIntegrityCheckEnabled
+    ) {
+        CompletedPart.Builder completedPartBuilder = CompletedPart.builder().eTag(partResponse.eTag()).partNumber(partNumber);
+        if (isRemoteDataIntegrityCheckEnabled) {
+            completedPartBuilder.checksumCRC32(partResponse.checksumCRC32());
+            CheckedContainer inputStreamCRC32Container = inputStreamContainers.get(partNumber - 1);
+            inputStreamCRC32Container.setChecksum(partResponse.checksumCRC32());
+            inputStreamContainers.set(partNumber - 1, inputStreamCRC32Container);
+        }
+        CompletedPart completedPart = completedPartBuilder.build();
+        completedParts.set(partNumber - 1, completedPart);
+        return completedPart;
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferEventLoopGroup.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferEventLoopGroup.java
new file mode 100644
index 0000000000000..7a99989796444
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferEventLoopGroup.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.repositories.s3.SocketAccess;
+
+import java.io.Closeable;
+import java.util.concurrent.TimeUnit;
+
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.epoll.Epoll;
+import io.netty.channel.epoll.EpollEventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.util.concurrent.Future;
+
+/**
+ * AsyncTransferEventLoopGroup is an encapsulation for netty {@link EventLoopGroup}
+ */
+public class AsyncTransferEventLoopGroup implements Closeable {
+    private static final String THREAD_PREFIX = "s3-async-transfer-worker";
+    private final Logger logger = LogManager.getLogger(AsyncTransferEventLoopGroup.class);
+
+    private final EventLoopGroup eventLoopGroup;
+
+    /**
+     * Construct a new AsyncTransferEventLoopGroup
+     *
+     * @param eventLoopThreads The number of event loop threads for this event loop group
+     */
+    public AsyncTransferEventLoopGroup(int eventLoopThreads) {
+        // Epoll event loop incurs less GC and provides better performance than Nio loop. Therefore,
+        // using epoll wherever available is preferred.
+        this.eventLoopGroup = SocketAccess.doPrivileged(
+            () -> Epoll.isAvailable()
+                ? new EpollEventLoopGroup(eventLoopThreads, OpenSearchExecutors.daemonThreadFactory(THREAD_PREFIX))
+                : new NioEventLoopGroup(eventLoopThreads, OpenSearchExecutors.daemonThreadFactory(THREAD_PREFIX))
+        );
+    }
+
+    public EventLoopGroup getEventLoopGroup() {
+        return eventLoopGroup;
+    }
+
+    @Override
+    public void close() {
+        Future<?> shutdownFuture = eventLoopGroup.shutdownGracefully(0, 5, TimeUnit.SECONDS);
+        shutdownFuture.awaitUninterruptibly();
+        if (!shutdownFuture.isSuccess()) {
+            logger.warn(new ParameterizedMessage("Error closing {} netty event loop group", THREAD_PREFIX), shutdownFuture.cause());
+        }
+    }
+
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferManager.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferManager.java
new file mode 100644
index 0000000000000..8d45c2167a3d1
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/AsyncTransferManager.java
@@ -0,0 +1,356 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import software.amazon.awssdk.core.async.AsyncRequestBody;
+import software.amazon.awssdk.core.exception.SdkClientException;
+import software.amazon.awssdk.http.HttpStatusCode;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.ChecksumAlgorithm;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
+import software.amazon.awssdk.services.s3.model.CompletedPart;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.S3Exception;
+import software.amazon.awssdk.utils.CompletableFutureUtils;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.exception.CorruptFileException;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.common.util.ByteUtils;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.repositories.s3.SocketAccess;
+import org.opensearch.repositories.s3.io.CheckedContainer;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicReferenceArray;
+import java.util.function.BiFunction;
+import java.util.function.Supplier;
+import java.util.stream.IntStream;
+
+import com.jcraft.jzlib.JZlib;
+
+/**
+ * A helper class that automatically uses multipart upload based on the size of the source object
+ */
+public final class AsyncTransferManager {
+    private static final Logger log = LogManager.getLogger(AsyncTransferManager.class);
+    private final ExecutorService executorService;
+    private final ExecutorService priorityExecutorService;
+    private final long minimumPartSize;
+
+    /**
+     * The max number of parts on S3 side is 10,000
+     */
+    private static final long MAX_UPLOAD_PARTS = 10_000;
+
+    /**
+     * Construct a new object of AsyncTransferManager
+     *
+     * @param minimumPartSize         The minimum part size for parallel multipart uploads
+     * @param executorService         The stream reader {@link ExecutorService} for normal priority uploads
+     * @param priorityExecutorService The stream read {@link ExecutorService} for high priority uploads
+     */
+    public AsyncTransferManager(long minimumPartSize, ExecutorService executorService, ExecutorService priorityExecutorService) {
+        this.executorService = executorService;
+        this.priorityExecutorService = priorityExecutorService;
+        this.minimumPartSize = minimumPartSize;
+    }
+
+    /**
+     * Upload an object to S3 using the async client
+     *
+     * @param s3AsyncClient S3 client to use for upload
+     * @param uploadRequest The {@link UploadRequest} object encapsulating all relevant details for upload
+     * @param streamContext The {@link StreamContext} to supply streams during upload
+     * @return A {@link CompletableFuture} to listen for upload completion
+     */
+    public CompletableFuture<Void> uploadObject(S3AsyncClient s3AsyncClient, UploadRequest uploadRequest, StreamContext streamContext) {
+
+        CompletableFuture<Void> returnFuture = new CompletableFuture<>();
+        try {
+            if (streamContext.getNumberOfParts() == 1) {
+                log.debug(() -> "Starting the upload as a single upload part request");
+                uploadInOneChunk(s3AsyncClient, uploadRequest, streamContext.provideStream(0), returnFuture);
+            } else {
+                log.debug(() -> "Starting the upload as multipart upload request");
+                uploadInParts(s3AsyncClient, uploadRequest, streamContext, returnFuture);
+            }
+        } catch (Throwable throwable) {
+            returnFuture.completeExceptionally(throwable);
+        }
+
+        return returnFuture;
+    }
+
+    private void uploadInParts(
+        S3AsyncClient s3AsyncClient,
+        UploadRequest uploadRequest,
+        StreamContext streamContext,
+        CompletableFuture<Void> returnFuture
+    ) {
+
+        CreateMultipartUploadRequest.Builder createMultipartUploadRequestBuilder = CreateMultipartUploadRequest.builder()
+            .bucket(uploadRequest.getBucket())
+            .key(uploadRequest.getKey());
+        if (uploadRequest.doRemoteDataIntegrityCheck()) {
+            createMultipartUploadRequestBuilder.checksumAlgorithm(ChecksumAlgorithm.CRC32);
+        }
+        CompletableFuture<CreateMultipartUploadResponse> createMultipartUploadFuture = SocketAccess.doPrivileged(
+            () -> s3AsyncClient.createMultipartUpload(createMultipartUploadRequestBuilder.build())
+        );
+
+        // Ensure cancellations are forwarded to the createMultipartUploadFuture future
+        CompletableFutureUtils.forwardExceptionTo(returnFuture, createMultipartUploadFuture);
+
+        createMultipartUploadFuture.whenComplete((createMultipartUploadResponse, throwable) -> {
+            if (throwable != null) {
+                handleException(returnFuture, () -> "Failed to initiate multipart upload", throwable);
+            } else {
+                log.debug(() -> "Initiated new multipart upload, uploadId: " + createMultipartUploadResponse.uploadId());
+                doUploadInParts(s3AsyncClient, uploadRequest, streamContext, returnFuture, createMultipartUploadResponse.uploadId());
+            }
+        });
+    }
+
+    private void doUploadInParts(
+        S3AsyncClient s3AsyncClient,
+        UploadRequest uploadRequest,
+        StreamContext streamContext,
+        CompletableFuture<Void> returnFuture,
+        String uploadId
+    ) {
+
+        // The list of completed parts must be sorted
+        AtomicReferenceArray<CompletedPart> completedParts = new AtomicReferenceArray<>(streamContext.getNumberOfParts());
+        AtomicReferenceArray<CheckedContainer> inputStreamContainers = new AtomicReferenceArray<>(streamContext.getNumberOfParts());
+
+        List<CompletableFuture<CompletedPart>> futures;
+        try {
+            futures = AsyncPartsHandler.uploadParts(
+                s3AsyncClient,
+                executorService,
+                priorityExecutorService,
+                uploadRequest,
+                streamContext,
+                uploadId,
+                completedParts,
+                inputStreamContainers
+            );
+        } catch (Exception ex) {
+            try {
+                AsyncPartsHandler.cleanUpParts(s3AsyncClient, uploadRequest, uploadId);
+            } finally {
+                returnFuture.completeExceptionally(ex);
+            }
+            return;
+        }
+
+        CompletableFutureUtils.allOfExceptionForwarded(futures.toArray(CompletableFuture[]::new)).thenApply(resp -> {
+            try {
+                uploadRequest.getUploadFinalizer().accept(true);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+            return resp;
+        }).thenApply(ignore -> {
+            if (uploadRequest.doRemoteDataIntegrityCheck()) {
+                mergeAndVerifyChecksum(inputStreamContainers, uploadRequest.getKey(), uploadRequest.getExpectedChecksum());
+            }
+            return null;
+        })
+            .thenCompose(ignore -> completeMultipartUpload(s3AsyncClient, uploadRequest, uploadId, completedParts))
+            .handle(handleExceptionOrResponse(s3AsyncClient, uploadRequest, returnFuture, uploadId))
+            .exceptionally(throwable -> {
+                handleException(returnFuture, () -> "Unexpected exception occurred", throwable);
+                return null;
+            });
+    }
+
+    private void mergeAndVerifyChecksum(
+        AtomicReferenceArray<CheckedContainer> inputStreamContainers,
+        String fileName,
+        long expectedChecksum
+    ) {
+        long resultantChecksum = fromBase64String(inputStreamContainers.get(0).getChecksum());
+        for (int index = 1; index < inputStreamContainers.length(); index++) {
+            long curChecksum = fromBase64String(inputStreamContainers.get(index).getChecksum());
+            resultantChecksum = JZlib.crc32_combine(resultantChecksum, curChecksum, inputStreamContainers.get(index).getContentLength());
+        }
+
+        if (resultantChecksum != expectedChecksum) {
+            throw new RuntimeException(new CorruptFileException("File level checksums didn't match combined part checksums", fileName));
+        }
+    }
+
+    private BiFunction<CompleteMultipartUploadResponse, Throwable, Void> handleExceptionOrResponse(
+        S3AsyncClient s3AsyncClient,
+        UploadRequest uploadRequest,
+        CompletableFuture<Void> returnFuture,
+        String uploadId
+    ) {
+
+        return (response, throwable) -> {
+            if (throwable != null) {
+                AsyncPartsHandler.cleanUpParts(s3AsyncClient, uploadRequest, uploadId);
+                handleException(returnFuture, () -> "Failed to send multipart upload requests.", throwable);
+            } else {
+                returnFuture.complete(null);
+            }
+
+            return null;
+        };
+    }
+
+    private CompletableFuture<CompleteMultipartUploadResponse> completeMultipartUpload(
+        S3AsyncClient s3AsyncClient,
+        UploadRequest uploadRequest,
+        String uploadId,
+        AtomicReferenceArray<CompletedPart> completedParts
+    ) {
+
+        log.debug(() -> new ParameterizedMessage("Sending completeMultipartUploadRequest, uploadId: {}", uploadId));
+        CompletedPart[] parts = IntStream.range(0, completedParts.length()).mapToObj(completedParts::get).toArray(CompletedPart[]::new);
+        CompleteMultipartUploadRequest completeMultipartUploadRequest = CompleteMultipartUploadRequest.builder()
+            .bucket(uploadRequest.getBucket())
+            .key(uploadRequest.getKey())
+            .uploadId(uploadId)
+            .multipartUpload(CompletedMultipartUpload.builder().parts(parts).build())
+            .build();
+
+        return SocketAccess.doPrivileged(() -> s3AsyncClient.completeMultipartUpload(completeMultipartUploadRequest));
+    }
+
+    private static String base64StringFromLong(Long val) {
+        return Base64.getEncoder().encodeToString(Arrays.copyOfRange(ByteUtils.toByteArrayBE(val), 4, 8));
+    }
+
+    private static long fromBase64String(String base64String) {
+        byte[] decodedBytes = Base64.getDecoder().decode(base64String);
+        if (decodedBytes.length != 4) {
+            throw new IllegalArgumentException("Invalid Base64 encoded CRC32 checksum");
+        }
+        long result = 0;
+        for (int i = 0; i < 4; i++) {
+            result <<= 8;
+            result |= (decodedBytes[i] & 0xFF);
+        }
+        return result;
+    }
+
+    private static void handleException(CompletableFuture<Void> returnFuture, Supplier<String> message, Throwable throwable) {
+        Throwable cause = throwable instanceof CompletionException ? throwable.getCause() : throwable;
+
+        if (cause instanceof Error) {
+            returnFuture.completeExceptionally(cause);
+        } else {
+            SdkClientException exception = SdkClientException.create(message.get(), cause);
+            returnFuture.completeExceptionally(exception);
+        }
+    }
+
+    /**
+     * Calculates the optimal part size of each part request if the upload operation is carried out as multipart upload.
+     */
+    public long calculateOptimalPartSize(long contentLengthOfSource) {
+        if (contentLengthOfSource < ByteSizeUnit.MB.toBytes(5)) {
+            return contentLengthOfSource;
+        }
+        double optimalPartSize = contentLengthOfSource / (double) MAX_UPLOAD_PARTS;
+        optimalPartSize = Math.ceil(optimalPartSize);
+        return (long) Math.max(optimalPartSize, minimumPartSize);
+    }
+
+    private void uploadInOneChunk(
+        S3AsyncClient s3AsyncClient,
+        UploadRequest uploadRequest,
+        InputStreamContainer inputStreamContainer,
+        CompletableFuture<Void> returnFuture
+    ) {
+        PutObjectRequest.Builder putObjectRequestBuilder = PutObjectRequest.builder()
+            .bucket(uploadRequest.getBucket())
+            .key(uploadRequest.getKey())
+            .contentLength(uploadRequest.getContentLength());
+        if (uploadRequest.doRemoteDataIntegrityCheck()) {
+            putObjectRequestBuilder.checksumAlgorithm(ChecksumAlgorithm.CRC32);
+            putObjectRequestBuilder.checksumCRC32(base64StringFromLong(uploadRequest.getExpectedChecksum()));
+        }
+        ExecutorService streamReadExecutor = uploadRequest.getWritePriority() == WritePriority.HIGH
+            ? priorityExecutorService
+            : executorService;
+        CompletableFuture<Void> putObjectFuture = SocketAccess.doPrivileged(
+            () -> s3AsyncClient.putObject(
+                putObjectRequestBuilder.build(),
+                AsyncRequestBody.fromInputStream(
+                    inputStreamContainer.getInputStream(),
+                    inputStreamContainer.getContentLength(),
+                    streamReadExecutor
+                )
+            ).handle((resp, throwable) -> {
+                if (throwable != null) {
+                    Throwable unwrappedThrowable = ExceptionsHelper.unwrap(throwable, S3Exception.class);
+                    if (unwrappedThrowable != null) {
+                        S3Exception s3Exception = (S3Exception) unwrappedThrowable;
+                        if (s3Exception.statusCode() == HttpStatusCode.BAD_REQUEST
+                            && "BadDigest".equals(s3Exception.awsErrorDetails().errorCode())) {
+                            throw new RuntimeException(new CorruptFileException(s3Exception, uploadRequest.getKey()));
+                        }
+                    }
+                    returnFuture.completeExceptionally(throwable);
+                } else {
+                    try {
+                        uploadRequest.getUploadFinalizer().accept(true);
+                    } catch (IOException e) {
+                        throw new RuntimeException(e);
+                    }
+                    returnFuture.complete(null);
+                }
+
+                return null;
+            }).handle((resp, throwable) -> {
+                if (throwable != null) {
+                    deleteUploadedObject(s3AsyncClient, uploadRequest);
+                    returnFuture.completeExceptionally(throwable);
+                }
+
+                return null;
+            })
+        );
+
+        CompletableFutureUtils.forwardExceptionTo(returnFuture, putObjectFuture);
+        CompletableFutureUtils.forwardResultTo(putObjectFuture, returnFuture);
+    }
+
+    private void deleteUploadedObject(S3AsyncClient s3AsyncClient, UploadRequest uploadRequest) {
+        DeleteObjectRequest deleteObjectRequest = DeleteObjectRequest.builder()
+            .bucket(uploadRequest.getBucket())
+            .key(uploadRequest.getKey())
+            .build();
+
+        SocketAccess.doPrivileged(() -> s3AsyncClient.deleteObject(deleteObjectRequest)).exceptionally(throwable -> {
+            log.error(() -> new ParameterizedMessage("Failed to delete uploaded object of key {}", uploadRequest.getKey()), throwable);
+            return null;
+        });
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/UploadRequest.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/UploadRequest.java
new file mode 100644
index 0000000000000..3804c8417eb9f
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/async/UploadRequest.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+
+import java.io.IOException;
+
+/**
+ * A model encapsulating all details for an upload to S3
+ */
+public class UploadRequest {
+    private final String bucket;
+    private final String key;
+    private final long contentLength;
+    private final WritePriority writePriority;
+    private final CheckedConsumer<Boolean, IOException> uploadFinalizer;
+    private final boolean doRemoteDataIntegrityCheck;
+    private final Long expectedChecksum;
+
+    /**
+     * Construct a new UploadRequest object
+     *
+     * @param bucket                     The name of the S3 bucket
+     * @param key                        Key of the file needed to be uploaded
+     * @param contentLength              Total content length of the file for upload
+     * @param writePriority              The priority of this upload
+     * @param uploadFinalizer            An upload finalizer to call once all parts are uploaded
+     * @param doRemoteDataIntegrityCheck A boolean to inform vendor plugins whether remote data integrity checks need to be done
+     * @param expectedChecksum           Checksum of the file being uploaded for remote data integrity check
+     */
+    public UploadRequest(
+        String bucket,
+        String key,
+        long contentLength,
+        WritePriority writePriority,
+        CheckedConsumer<Boolean, IOException> uploadFinalizer,
+        boolean doRemoteDataIntegrityCheck,
+        Long expectedChecksum
+    ) {
+        this.bucket = bucket;
+        this.key = key;
+        this.contentLength = contentLength;
+        this.writePriority = writePriority;
+        this.uploadFinalizer = uploadFinalizer;
+        this.doRemoteDataIntegrityCheck = doRemoteDataIntegrityCheck;
+        this.expectedChecksum = expectedChecksum;
+    }
+
+    public String getBucket() {
+        return bucket;
+    }
+
+    public String getKey() {
+        return key;
+    }
+
+    public long getContentLength() {
+        return contentLength;
+    }
+
+    public WritePriority getWritePriority() {
+        return writePriority;
+    }
+
+    public CheckedConsumer<Boolean, IOException> getUploadFinalizer() {
+        return uploadFinalizer;
+    }
+
+    public boolean doRemoteDataIntegrityCheck() {
+        return doRemoteDataIntegrityCheck;
+    }
+
+    public Long getExpectedChecksum() {
+        return expectedChecksum;
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/io/CheckedContainer.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/io/CheckedContainer.java
new file mode 100644
index 0000000000000..0596424093dca
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/io/CheckedContainer.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.io;
+
+public class CheckedContainer {
+
+    private String checksum;
+    private long contentLength;
+
+    public CheckedContainer(long contentLength) {
+        this.contentLength = contentLength;
+    }
+
+    public void setChecksum(String checksum) {
+        this.checksum = checksum;
+    }
+
+    public String getChecksum() {
+        return checksum;
+    }
+
+    public long getContentLength() {
+        return contentLength;
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/AwsRequestSigner.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/AwsRequestSigner.java
new file mode 100644
index 0000000000000..036629c22245d
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/AwsRequestSigner.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.utils;
+
+import software.amazon.awssdk.auth.signer.Aws4Signer;
+import software.amazon.awssdk.auth.signer.Aws4UnsignedPayloadSigner;
+import software.amazon.awssdk.auth.signer.AwsS3V4Signer;
+import software.amazon.awssdk.core.signer.NoOpSigner;
+import software.amazon.awssdk.core.signer.Signer;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public enum AwsRequestSigner {
+
+    VERSION_FOUR_SIGNER("AWS4SignerType", Aws4Signer.create()),
+    VERSION_FOUR_UNSIGNED_PAYLOAD_SIGNER("AWS4UnsignedPayloadSignerType", Aws4UnsignedPayloadSigner.create()),
+    NO_OP_SIGNER("NoOpSignerType", new NoOpSigner()),
+    S3_V4_SIGNER("AWSS3V4SignerType", AwsS3V4Signer.create());
+
+    private final String name;
+    private final Signer signer;
+
+    AwsRequestSigner(String name, Signer signer) {
+        this.name = name;
+        this.signer = signer;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Signer getSigner() {
+        return signer;
+    }
+
+    public static AwsRequestSigner fromSignerName(String signerName) {
+        List<AwsRequestSigner> matchingSigners = Arrays.stream(AwsRequestSigner.values())
+            .filter(awsRequestSigner -> awsRequestSigner.getName().equals(signerName))
+            .collect(Collectors.toList());
+        if (matchingSigners.size() < 1) {
+            throw new IllegalArgumentException("No matching signers found for signerName: " + signerName);
+        } else if (matchingSigners.size() > 1) {
+            throw new IllegalArgumentException("More than 1 matching signers found for signerName: " + signerName);
+        }
+        return matchingSigners.get(0);
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/HttpRangeUtils.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/HttpRangeUtils.java
new file mode 100644
index 0000000000000..2e2fc9b86a45b
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/HttpRangeUtils.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.utils;
+
+import software.amazon.awssdk.core.exception.SdkException;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public final class HttpRangeUtils {
+    private static final Pattern RANGE_PATTERN = Pattern.compile("^bytes\\s+(\\d+)-\\d+[/\\d*]+$");
+
+    /**
+     * Parses the content range header string value to calculate the start (offset) of the HTTP response.
+     * Tests against the RFC9110 specification of content range string.
+     * Sample values: "bytes 0-10/200", "bytes 0-10/*"
+     *  <a href="https://www.rfc-editor.org/rfc/rfc9110.html#name-content-range">Details here</a>
+     * @param headerValue Header content range string value from the HTTP response
+     * @return Start (Offset) value of the HTTP response
+     */
+    public static Long getStartOffsetFromRangeHeader(String headerValue) {
+        Matcher matcher = RANGE_PATTERN.matcher(headerValue);
+        if (!matcher.find()) {
+            throw SdkException.create("Regex match for Content-Range header {" + headerValue + "} failed", new RuntimeException());
+        }
+        return Long.parseLong(matcher.group(1));
+    }
+
+    /**
+     * Provides a byte range string per <a href="https://www.rfc-editor.org/rfc/rfc9110.html#name-byte-ranges">RFC 9110</a>
+     * @param start start position (inclusive)
+     * @param end end position (inclusive)
+     * @return A 'bytes=start-end' string
+     */
+    public static String toHttpRangeHeader(long start, long end) {
+        return "bytes=" + start + "-" + end;
+    }
+}
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/Protocol.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/Protocol.java
new file mode 100644
index 0000000000000..0dbd9364f9c53
--- /dev/null
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/Protocol.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.utils;
+
+/**
+ * Represents the communication protocol to use when sending requests to AWS.
+ * <p>
+ * Communication over HTTPS is the default, and is more secure than HTTP, which
+ * is why AWS recommends using HTTPS. HTTPS connections can use more system
+ * resources because of the extra work to encrypt network traffic, so the option
+ * to use HTTP is available in case users need it.
+ */
+public enum Protocol {
+
+    /**
+     * HTTP Protocol - Using the HTTP protocol is less secure than HTTPS, but
+     * can slightly reduce the system resources used when communicating with
+     * AWS.
+     */
+    HTTP("http"),
+
+    /**
+     * HTTPS Protocol - Using the HTTPS protocol is more secure than using the
+     * HTTP protocol, but may use slightly more system resources. AWS recommends
+     * using HTTPS for maximize security.
+     */
+    HTTPS("https");
+
+    private final String protocol;
+
+    private Protocol(String protocol) {
+        this.protocol = protocol;
+    }
+
+    /* (non-Javadoc)
+     * @see java.lang.Enum#toString()
+     */
+    @Override
+    public String toString() {
+        return protocol;
+    }
+}
diff --git a/plugins/repository-s3/src/main/plugin-metadata/plugin-security.policy b/plugins/repository-s3/src/main/plugin-metadata/plugin-security.policy
index f6c154bb3b14d..106103d45e7eb 100644
--- a/plugins/repository-s3/src/main/plugin-metadata/plugin-security.policy
+++ b/plugins/repository-s3/src/main/plugin-metadata/plugin-security.policy
@@ -35,6 +35,7 @@ grant {
   // TODO: get these fixed in aws sdk
   permission java.lang.RuntimePermission "accessDeclaredMembers";
   permission java.lang.RuntimePermission "getClassLoader";
+  permission java.lang.RuntimePermission "setContextClassLoader";
   // Needed because of problems in AmazonS3Client:
   // When no region is set on a AmazonS3Client instance, the
   // AWS SDK loads all known partitions from a JSON file and
@@ -56,4 +57,10 @@ grant {
 
   // only for tests : org.opensearch.repositories.s3.S3RepositoryPlugin
   permission java.util.PropertyPermission "opensearch.allow_insecure_settings", "read,write";
+  permission java.util.PropertyPermission "aws.sharedCredentialsFile", "read,write";
+  permission java.util.PropertyPermission "aws.configFile", "read,write";
+  permission java.util.PropertyPermission "opensearch.path.conf", "read,write";
+  permission java.io.FilePermission "config", "read";
+
+  permission java.lang.RuntimePermission "accessDeclaredMembers";
 };
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AbstractS3RepositoryTestCase.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AbstractS3RepositoryTestCase.java
new file mode 100644
index 0000000000000..aae86c4f93587
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AbstractS3RepositoryTestCase.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.profiles.ProfileFileSystemSetting;
+
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.file.Path;
+
+public abstract class AbstractS3RepositoryTestCase extends OpenSearchTestCase {
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        setUpAwsProfile();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        resetAwsProfile();
+        super.tearDown();
+    }
+
+    protected Path configPath() {
+        return PathUtils.get("config");
+    }
+
+    private String previousOpenSearchPathConf;
+    private String awsSharedCredentialsFile;
+    private String awsConfigFile;
+
+    @SuppressForbidden(reason = "set predictable aws defaults")
+    private void setUpAwsProfile() throws Exception {
+        previousOpenSearchPathConf = SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
+        awsSharedCredentialsFile = System.getProperty(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property());
+        awsConfigFile = System.getProperty(ProfileFileSystemSetting.AWS_CONFIG_FILE.property());
+        SocketAccess.doPrivilegedVoid(S3Service::setDefaultAwsProfilePath);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetAwsProfile() throws Exception {
+        resetPropertyValue("opensearch.path.conf", previousOpenSearchPathConf);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_SHARED_CREDENTIALS_FILE.property(), awsSharedCredentialsFile);
+        resetPropertyValue(ProfileFileSystemSetting.AWS_CONFIG_FILE.property(), awsConfigFile);
+    }
+
+    @SuppressForbidden(reason = "reset aws settings")
+    private void resetPropertyValue(String key, String value) {
+        if (value != null) {
+            SocketAccess.doPrivileged(() -> System.setProperty(key, value));
+        } else {
+            SocketAccess.doPrivileged(() -> System.clearProperty(key));
+        }
+    }
+}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AmazonS3Wrapper.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AmazonS3Wrapper.java
deleted file mode 100644
index 47f2e4fa14297..0000000000000
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AmazonS3Wrapper.java
+++ /dev/null
@@ -1,808 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.repositories.s3;
-
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.AmazonServiceException;
-import com.amazonaws.AmazonWebServiceRequest;
-import com.amazonaws.HttpMethod;
-import com.amazonaws.regions.Region;
-import com.amazonaws.services.s3.AbstractAmazonS3;
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.s3.S3ClientOptions;
-import com.amazonaws.services.s3.S3ResponseMetadata;
-import com.amazonaws.services.s3.model.AbortMultipartUploadRequest;
-import com.amazonaws.services.s3.model.AccessControlList;
-import com.amazonaws.services.s3.model.Bucket;
-import com.amazonaws.services.s3.model.BucketCrossOriginConfiguration;
-import com.amazonaws.services.s3.model.BucketLifecycleConfiguration;
-import com.amazonaws.services.s3.model.BucketLoggingConfiguration;
-import com.amazonaws.services.s3.model.BucketNotificationConfiguration;
-import com.amazonaws.services.s3.model.BucketPolicy;
-import com.amazonaws.services.s3.model.BucketReplicationConfiguration;
-import com.amazonaws.services.s3.model.BucketTaggingConfiguration;
-import com.amazonaws.services.s3.model.BucketVersioningConfiguration;
-import com.amazonaws.services.s3.model.BucketWebsiteConfiguration;
-import com.amazonaws.services.s3.model.CannedAccessControlList;
-import com.amazonaws.services.s3.model.CompleteMultipartUploadRequest;
-import com.amazonaws.services.s3.model.CompleteMultipartUploadResult;
-import com.amazonaws.services.s3.model.CopyObjectRequest;
-import com.amazonaws.services.s3.model.CopyObjectResult;
-import com.amazonaws.services.s3.model.CopyPartRequest;
-import com.amazonaws.services.s3.model.CopyPartResult;
-import com.amazonaws.services.s3.model.CreateBucketRequest;
-import com.amazonaws.services.s3.model.DeleteBucketCrossOriginConfigurationRequest;
-import com.amazonaws.services.s3.model.DeleteBucketLifecycleConfigurationRequest;
-import com.amazonaws.services.s3.model.DeleteBucketPolicyRequest;
-import com.amazonaws.services.s3.model.DeleteBucketReplicationConfigurationRequest;
-import com.amazonaws.services.s3.model.DeleteBucketRequest;
-import com.amazonaws.services.s3.model.DeleteBucketTaggingConfigurationRequest;
-import com.amazonaws.services.s3.model.DeleteBucketWebsiteConfigurationRequest;
-import com.amazonaws.services.s3.model.DeleteObjectRequest;
-import com.amazonaws.services.s3.model.DeleteObjectsRequest;
-import com.amazonaws.services.s3.model.DeleteObjectsResult;
-import com.amazonaws.services.s3.model.DeleteVersionRequest;
-import com.amazonaws.services.s3.model.GeneratePresignedUrlRequest;
-import com.amazonaws.services.s3.model.GetBucketAclRequest;
-import com.amazonaws.services.s3.model.GetBucketCrossOriginConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketLifecycleConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketLocationRequest;
-import com.amazonaws.services.s3.model.GetBucketLoggingConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketNotificationConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketPolicyRequest;
-import com.amazonaws.services.s3.model.GetBucketReplicationConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketTaggingConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketVersioningConfigurationRequest;
-import com.amazonaws.services.s3.model.GetBucketWebsiteConfigurationRequest;
-import com.amazonaws.services.s3.model.GetObjectAclRequest;
-import com.amazonaws.services.s3.model.GetObjectMetadataRequest;
-import com.amazonaws.services.s3.model.GetObjectRequest;
-import com.amazonaws.services.s3.model.GetS3AccountOwnerRequest;
-import com.amazonaws.services.s3.model.HeadBucketRequest;
-import com.amazonaws.services.s3.model.HeadBucketResult;
-import com.amazonaws.services.s3.model.InitiateMultipartUploadRequest;
-import com.amazonaws.services.s3.model.InitiateMultipartUploadResult;
-import com.amazonaws.services.s3.model.ListBucketsRequest;
-import com.amazonaws.services.s3.model.ListMultipartUploadsRequest;
-import com.amazonaws.services.s3.model.ListNextBatchOfObjectsRequest;
-import com.amazonaws.services.s3.model.ListNextBatchOfVersionsRequest;
-import com.amazonaws.services.s3.model.ListObjectsRequest;
-import com.amazonaws.services.s3.model.ListPartsRequest;
-import com.amazonaws.services.s3.model.ListVersionsRequest;
-import com.amazonaws.services.s3.model.MultipartUploadListing;
-import com.amazonaws.services.s3.model.ObjectListing;
-import com.amazonaws.services.s3.model.ObjectMetadata;
-import com.amazonaws.services.s3.model.Owner;
-import com.amazonaws.services.s3.model.PartListing;
-import com.amazonaws.services.s3.model.PutObjectRequest;
-import com.amazonaws.services.s3.model.PutObjectResult;
-import com.amazonaws.services.s3.model.RestoreObjectRequest;
-import com.amazonaws.services.s3.model.S3Object;
-import com.amazonaws.services.s3.model.SetBucketAclRequest;
-import com.amazonaws.services.s3.model.SetBucketCrossOriginConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketLifecycleConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketLoggingConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketNotificationConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketPolicyRequest;
-import com.amazonaws.services.s3.model.SetBucketReplicationConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketTaggingConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketVersioningConfigurationRequest;
-import com.amazonaws.services.s3.model.SetBucketWebsiteConfigurationRequest;
-import com.amazonaws.services.s3.model.SetObjectAclRequest;
-import com.amazonaws.services.s3.model.StorageClass;
-import com.amazonaws.services.s3.model.UploadPartRequest;
-import com.amazonaws.services.s3.model.UploadPartResult;
-import com.amazonaws.services.s3.model.VersionListing;
-import org.opensearch.common.SuppressForbidden;
-
-import java.io.File;
-import java.io.InputStream;
-import java.net.URL;
-import java.util.Date;
-import java.util.List;
-
-@SuppressForbidden(reason = "implements AWS api that uses java.io.File!")
-public class AmazonS3Wrapper extends AbstractAmazonS3 {
-
-    protected AmazonS3 delegate;
-
-    public AmazonS3Wrapper(AmazonS3 delegate) {
-        this.delegate = delegate;
-    }
-
-    @Override
-    public void setEndpoint(String endpoint) {
-        delegate.setEndpoint(endpoint);
-    }
-
-    @Override
-    public void setRegion(Region region) throws IllegalArgumentException {
-        delegate.setRegion(region);
-    }
-
-    @Override
-    public void setS3ClientOptions(S3ClientOptions clientOptions) {
-        delegate.setS3ClientOptions(clientOptions);
-    }
-
-    @Override
-    public void changeObjectStorageClass(String bucketName, String key, StorageClass newStorageClass) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.changeObjectStorageClass(bucketName, key, newStorageClass);
-    }
-
-    @Override
-    public void setObjectRedirectLocation(String bucketName, String key, String newRedirectLocation) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.setObjectRedirectLocation(bucketName, key, newRedirectLocation);
-    }
-
-    @Override
-    public ObjectListing listObjects(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.listObjects(bucketName);
-    }
-
-    @Override
-    public ObjectListing listObjects(String bucketName, String prefix) throws AmazonClientException, AmazonServiceException {
-        return delegate.listObjects(bucketName, prefix);
-    }
-
-    @Override
-    public ObjectListing listObjects(ListObjectsRequest listObjectsRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.listObjects(listObjectsRequest);
-    }
-
-    @Override
-    public ObjectListing listNextBatchOfObjects(ObjectListing previousObjectListing) throws AmazonClientException, AmazonServiceException {
-        return delegate.listNextBatchOfObjects(previousObjectListing);
-    }
-
-    @Override
-    public VersionListing listVersions(String bucketName, String prefix) throws AmazonClientException, AmazonServiceException {
-        return delegate.listVersions(bucketName, prefix);
-    }
-
-    @Override
-    public VersionListing listNextBatchOfVersions(VersionListing previousVersionListing) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.listNextBatchOfVersions(previousVersionListing);
-    }
-
-    @Override
-    public VersionListing listVersions(
-        String bucketName,
-        String prefix,
-        String keyMarker,
-        String versionIdMarker,
-        String delimiter,
-        Integer maxResults
-    ) throws AmazonClientException, AmazonServiceException {
-        return delegate.listVersions(bucketName, prefix, keyMarker, versionIdMarker, delimiter, maxResults);
-    }
-
-    @Override
-    public VersionListing listVersions(ListVersionsRequest listVersionsRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.listVersions(listVersionsRequest);
-    }
-
-    @Override
-    public Owner getS3AccountOwner() throws AmazonClientException, AmazonServiceException {
-        return delegate.getS3AccountOwner();
-    }
-
-    @Override
-    public boolean doesBucketExist(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.doesBucketExist(bucketName);
-    }
-
-    @Override
-    public List<Bucket> listBuckets() throws AmazonClientException, AmazonServiceException {
-        return delegate.listBuckets();
-    }
-
-    @Override
-    public List<Bucket> listBuckets(ListBucketsRequest listBucketsRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.listBuckets(listBucketsRequest);
-    }
-
-    @Override
-    public String getBucketLocation(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketLocation(bucketName);
-    }
-
-    @Override
-    public String getBucketLocation(GetBucketLocationRequest getBucketLocationRequest) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketLocation(getBucketLocationRequest);
-    }
-
-    @Override
-    public Bucket createBucket(CreateBucketRequest createBucketRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.createBucket(createBucketRequest);
-    }
-
-    @Override
-    public Bucket createBucket(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.createBucket(bucketName);
-    }
-
-    @Override
-    public Bucket createBucket(String bucketName, com.amazonaws.services.s3.model.Region region) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.createBucket(bucketName, region);
-    }
-
-    @Override
-    public Bucket createBucket(String bucketName, String region) throws AmazonClientException, AmazonServiceException {
-        return delegate.createBucket(bucketName, region);
-    }
-
-    @Override
-    public AccessControlList getObjectAcl(String bucketName, String key) throws AmazonClientException, AmazonServiceException {
-        return delegate.getObjectAcl(bucketName, key);
-    }
-
-    @Override
-    public AccessControlList getObjectAcl(String bucketName, String key, String versionId) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getObjectAcl(bucketName, key, versionId);
-    }
-
-    @Override
-    public AccessControlList getObjectAcl(GetObjectAclRequest getObjectAclRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.getObjectAcl(getObjectAclRequest);
-    }
-
-    @Override
-    public void setObjectAcl(String bucketName, String key, AccessControlList acl) throws AmazonClientException, AmazonServiceException {
-        delegate.setObjectAcl(bucketName, key, acl);
-    }
-
-    @Override
-    public void setObjectAcl(String bucketName, String key, CannedAccessControlList acl) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.setObjectAcl(bucketName, key, acl);
-    }
-
-    @Override
-    public void setObjectAcl(String bucketName, String key, String versionId, AccessControlList acl) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.setObjectAcl(bucketName, key, versionId, acl);
-    }
-
-    @Override
-    public void setObjectAcl(String bucketName, String key, String versionId, CannedAccessControlList acl) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.setObjectAcl(bucketName, key, versionId, acl);
-    }
-
-    @Override
-    public void setObjectAcl(SetObjectAclRequest setObjectAclRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.setObjectAcl(setObjectAclRequest);
-    }
-
-    @Override
-    public AccessControlList getBucketAcl(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketAcl(bucketName);
-    }
-
-    @Override
-    public void setBucketAcl(SetBucketAclRequest setBucketAclRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketAcl(setBucketAclRequest);
-    }
-
-    @Override
-    public AccessControlList getBucketAcl(GetBucketAclRequest getBucketAclRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketAcl(getBucketAclRequest);
-    }
-
-    @Override
-    public void setBucketAcl(String bucketName, AccessControlList acl) throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketAcl(bucketName, acl);
-    }
-
-    @Override
-    public void setBucketAcl(String bucketName, CannedAccessControlList acl) throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketAcl(bucketName, acl);
-    }
-
-    @Override
-    public ObjectMetadata getObjectMetadata(String bucketName, String key) throws AmazonClientException, AmazonServiceException {
-        return delegate.getObjectMetadata(bucketName, key);
-    }
-
-    @Override
-    public ObjectMetadata getObjectMetadata(GetObjectMetadataRequest getObjectMetadataRequest) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getObjectMetadata(getObjectMetadataRequest);
-    }
-
-    @Override
-    public S3Object getObject(String bucketName, String key) throws AmazonClientException, AmazonServiceException {
-        return delegate.getObject(bucketName, key);
-    }
-
-    @Override
-    public S3Object getObject(GetObjectRequest getObjectRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.getObject(getObjectRequest);
-    }
-
-    @Override
-    public ObjectMetadata getObject(GetObjectRequest getObjectRequest, File destinationFile) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getObject(getObjectRequest, destinationFile);
-    }
-
-    @Override
-    public void deleteBucket(DeleteBucketRequest deleteBucketRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteBucket(deleteBucketRequest);
-    }
-
-    @Override
-    public void deleteBucket(String bucketName) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteBucket(bucketName);
-    }
-
-    @Override
-    public void setBucketReplicationConfiguration(String bucketName, BucketReplicationConfiguration configuration)
-        throws AmazonServiceException, AmazonClientException {
-        delegate.setBucketReplicationConfiguration(bucketName, configuration);
-    }
-
-    @Override
-    public void setBucketReplicationConfiguration(SetBucketReplicationConfigurationRequest setBucketReplicationConfigurationRequest)
-        throws AmazonServiceException, AmazonClientException {
-        delegate.setBucketReplicationConfiguration(setBucketReplicationConfigurationRequest);
-    }
-
-    @Override
-    public BucketReplicationConfiguration getBucketReplicationConfiguration(String bucketName) throws AmazonServiceException,
-        AmazonClientException {
-        return delegate.getBucketReplicationConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketReplicationConfiguration(String bucketName) throws AmazonServiceException, AmazonClientException {
-        delegate.deleteBucketReplicationConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketReplicationConfiguration(DeleteBucketReplicationConfigurationRequest request) throws AmazonServiceException,
-        AmazonClientException {
-        delegate.deleteBucketReplicationConfiguration(request);
-    }
-
-    @Override
-    public boolean doesObjectExist(String bucketName, String objectName) throws AmazonServiceException, AmazonClientException {
-        return delegate.doesObjectExist(bucketName, objectName);
-    }
-
-    @Override
-    public PutObjectResult putObject(PutObjectRequest putObjectRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.putObject(putObjectRequest);
-    }
-
-    @Override
-    public PutObjectResult putObject(String bucketName, String key, File file) throws AmazonClientException, AmazonServiceException {
-        return delegate.putObject(bucketName, key, file);
-    }
-
-    @Override
-    public PutObjectResult putObject(String bucketName, String key, InputStream input, ObjectMetadata metadata)
-        throws AmazonClientException, AmazonServiceException {
-        return delegate.putObject(bucketName, key, input, metadata);
-    }
-
-    @Override
-    public CopyObjectResult copyObject(String sourceBucketName, String sourceKey, String destinationBucketName, String destinationKey)
-        throws AmazonClientException, AmazonServiceException {
-        return delegate.copyObject(sourceBucketName, sourceKey, destinationBucketName, destinationKey);
-    }
-
-    @Override
-    public CopyObjectResult copyObject(CopyObjectRequest copyObjectRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.copyObject(copyObjectRequest);
-    }
-
-    @Override
-    public CopyPartResult copyPart(CopyPartRequest copyPartRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.copyPart(copyPartRequest);
-    }
-
-    @Override
-    public void deleteObject(String bucketName, String key) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteObject(bucketName, key);
-    }
-
-    @Override
-    public void deleteObject(DeleteObjectRequest deleteObjectRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteObject(deleteObjectRequest);
-    }
-
-    @Override
-    public DeleteObjectsResult deleteObjects(DeleteObjectsRequest deleteObjectsRequest) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.deleteObjects(deleteObjectsRequest);
-    }
-
-    @Override
-    public void deleteVersion(String bucketName, String key, String versionId) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteVersion(bucketName, key, versionId);
-    }
-
-    @Override
-    public void deleteVersion(DeleteVersionRequest deleteVersionRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteVersion(deleteVersionRequest);
-    }
-
-    @Override
-    public BucketLoggingConfiguration getBucketLoggingConfiguration(String bucketName) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketLoggingConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketLoggingConfiguration(SetBucketLoggingConfigurationRequest setBucketLoggingConfigurationRequest)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketLoggingConfiguration(setBucketLoggingConfigurationRequest);
-    }
-
-    @Override
-    public BucketVersioningConfiguration getBucketVersioningConfiguration(String bucketName) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketVersioningConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketVersioningConfiguration(SetBucketVersioningConfigurationRequest setBucketVersioningConfigurationRequest)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketVersioningConfiguration(setBucketVersioningConfigurationRequest);
-    }
-
-    @Override
-    public BucketLifecycleConfiguration getBucketLifecycleConfiguration(String bucketName) {
-        return delegate.getBucketLifecycleConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketLifecycleConfiguration(String bucketName, BucketLifecycleConfiguration bucketLifecycleConfiguration) {
-        delegate.setBucketLifecycleConfiguration(bucketName, bucketLifecycleConfiguration);
-    }
-
-    @Override
-    public void setBucketLifecycleConfiguration(SetBucketLifecycleConfigurationRequest setBucketLifecycleConfigurationRequest) {
-        delegate.setBucketLifecycleConfiguration(setBucketLifecycleConfigurationRequest);
-    }
-
-    @Override
-    public void deleteBucketLifecycleConfiguration(String bucketName) {
-        delegate.deleteBucketLifecycleConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketLifecycleConfiguration(DeleteBucketLifecycleConfigurationRequest deleteBucketLifecycleConfigurationRequest) {
-        delegate.deleteBucketLifecycleConfiguration(deleteBucketLifecycleConfigurationRequest);
-    }
-
-    @Override
-    public BucketCrossOriginConfiguration getBucketCrossOriginConfiguration(String bucketName) {
-        return delegate.getBucketCrossOriginConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketCrossOriginConfiguration(String bucketName, BucketCrossOriginConfiguration bucketCrossOriginConfiguration) {
-        delegate.setBucketCrossOriginConfiguration(bucketName, bucketCrossOriginConfiguration);
-    }
-
-    @Override
-    public void setBucketCrossOriginConfiguration(SetBucketCrossOriginConfigurationRequest setBucketCrossOriginConfigurationRequest) {
-        delegate.setBucketCrossOriginConfiguration(setBucketCrossOriginConfigurationRequest);
-    }
-
-    @Override
-    public void deleteBucketCrossOriginConfiguration(String bucketName) {
-        delegate.deleteBucketCrossOriginConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketCrossOriginConfiguration(
-        DeleteBucketCrossOriginConfigurationRequest deleteBucketCrossOriginConfigurationRequest
-    ) {
-        delegate.deleteBucketCrossOriginConfiguration(deleteBucketCrossOriginConfigurationRequest);
-    }
-
-    @Override
-    public BucketTaggingConfiguration getBucketTaggingConfiguration(String bucketName) {
-        return delegate.getBucketTaggingConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketTaggingConfiguration(String bucketName, BucketTaggingConfiguration bucketTaggingConfiguration) {
-        delegate.setBucketTaggingConfiguration(bucketName, bucketTaggingConfiguration);
-    }
-
-    @Override
-    public void setBucketTaggingConfiguration(SetBucketTaggingConfigurationRequest setBucketTaggingConfigurationRequest) {
-        delegate.setBucketTaggingConfiguration(setBucketTaggingConfigurationRequest);
-    }
-
-    @Override
-    public void deleteBucketTaggingConfiguration(String bucketName) {
-        delegate.deleteBucketTaggingConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketTaggingConfiguration(DeleteBucketTaggingConfigurationRequest deleteBucketTaggingConfigurationRequest) {
-        delegate.deleteBucketTaggingConfiguration(deleteBucketTaggingConfigurationRequest);
-    }
-
-    @Override
-    public BucketNotificationConfiguration getBucketNotificationConfiguration(String bucketName) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketNotificationConfiguration(bucketName);
-    }
-
-    @Override
-    public void setBucketNotificationConfiguration(SetBucketNotificationConfigurationRequest setBucketNotificationConfigurationRequest)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketNotificationConfiguration(setBucketNotificationConfigurationRequest);
-    }
-
-    @Override
-    public void setBucketNotificationConfiguration(String bucketName, BucketNotificationConfiguration bucketNotificationConfiguration)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketNotificationConfiguration(bucketName, bucketNotificationConfiguration);
-    }
-
-    @Override
-    public BucketWebsiteConfiguration getBucketWebsiteConfiguration(String bucketName) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketWebsiteConfiguration(bucketName);
-    }
-
-    @Override
-    public BucketWebsiteConfiguration getBucketWebsiteConfiguration(
-        GetBucketWebsiteConfigurationRequest getBucketWebsiteConfigurationRequest
-    ) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketWebsiteConfiguration(getBucketWebsiteConfigurationRequest);
-    }
-
-    @Override
-    public void setBucketWebsiteConfiguration(String bucketName, BucketWebsiteConfiguration configuration) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.setBucketWebsiteConfiguration(bucketName, configuration);
-    }
-
-    @Override
-    public void setBucketWebsiteConfiguration(SetBucketWebsiteConfigurationRequest setBucketWebsiteConfigurationRequest)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketWebsiteConfiguration(setBucketWebsiteConfigurationRequest);
-    }
-
-    @Override
-    public void deleteBucketWebsiteConfiguration(String bucketName) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteBucketWebsiteConfiguration(bucketName);
-    }
-
-    @Override
-    public void deleteBucketWebsiteConfiguration(DeleteBucketWebsiteConfigurationRequest deleteBucketWebsiteConfigurationRequest)
-        throws AmazonClientException, AmazonServiceException {
-        delegate.deleteBucketWebsiteConfiguration(deleteBucketWebsiteConfigurationRequest);
-    }
-
-    @Override
-    public BucketPolicy getBucketPolicy(String bucketName) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketPolicy(bucketName);
-    }
-
-    @Override
-    public BucketPolicy getBucketPolicy(GetBucketPolicyRequest getBucketPolicyRequest) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.getBucketPolicy(getBucketPolicyRequest);
-    }
-
-    @Override
-    public void setBucketPolicy(String bucketName, String policyText) throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketPolicy(bucketName, policyText);
-    }
-
-    @Override
-    public void setBucketPolicy(SetBucketPolicyRequest setBucketPolicyRequest) throws AmazonClientException, AmazonServiceException {
-        delegate.setBucketPolicy(setBucketPolicyRequest);
-    }
-
-    @Override
-    public void deleteBucketPolicy(String bucketName) throws AmazonClientException, AmazonServiceException {
-        delegate.deleteBucketPolicy(bucketName);
-    }
-
-    @Override
-    public void deleteBucketPolicy(DeleteBucketPolicyRequest deleteBucketPolicyRequest) throws AmazonClientException,
-        AmazonServiceException {
-        delegate.deleteBucketPolicy(deleteBucketPolicyRequest);
-    }
-
-    @Override
-    public URL generatePresignedUrl(String bucketName, String key, Date expiration) throws AmazonClientException {
-        return delegate.generatePresignedUrl(bucketName, key, expiration);
-    }
-
-    @Override
-    public URL generatePresignedUrl(String bucketName, String key, Date expiration, HttpMethod method) throws AmazonClientException {
-        return delegate.generatePresignedUrl(bucketName, key, expiration, method);
-    }
-
-    @Override
-    public URL generatePresignedUrl(GeneratePresignedUrlRequest generatePresignedUrlRequest) throws AmazonClientException {
-        return delegate.generatePresignedUrl(generatePresignedUrlRequest);
-    }
-
-    @Override
-    public InitiateMultipartUploadResult initiateMultipartUpload(InitiateMultipartUploadRequest request) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.initiateMultipartUpload(request);
-    }
-
-    @Override
-    public UploadPartResult uploadPart(UploadPartRequest request) throws AmazonClientException, AmazonServiceException {
-        return delegate.uploadPart(request);
-    }
-
-    @Override
-    public PartListing listParts(ListPartsRequest request) throws AmazonClientException, AmazonServiceException {
-        return delegate.listParts(request);
-    }
-
-    @Override
-    public void abortMultipartUpload(AbortMultipartUploadRequest request) throws AmazonClientException, AmazonServiceException {
-        delegate.abortMultipartUpload(request);
-    }
-
-    @Override
-    public CompleteMultipartUploadResult completeMultipartUpload(CompleteMultipartUploadRequest request) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.completeMultipartUpload(request);
-    }
-
-    @Override
-    public MultipartUploadListing listMultipartUploads(ListMultipartUploadsRequest request) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.listMultipartUploads(request);
-    }
-
-    @Override
-    public S3ResponseMetadata getCachedResponseMetadata(AmazonWebServiceRequest request) {
-        return delegate.getCachedResponseMetadata(request);
-    }
-
-    @Override
-    public void restoreObject(RestoreObjectRequest copyGlacierObjectRequest) throws AmazonServiceException {
-        delegate.restoreObject(copyGlacierObjectRequest);
-    }
-
-    @Override
-    public void restoreObject(String bucketName, String key, int expirationInDays) throws AmazonServiceException {
-        delegate.restoreObject(bucketName, key, expirationInDays);
-    }
-
-    @Override
-    public void enableRequesterPays(String bucketName) throws AmazonServiceException, AmazonClientException {
-        delegate.enableRequesterPays(bucketName);
-    }
-
-    @Override
-    public void disableRequesterPays(String bucketName) throws AmazonServiceException, AmazonClientException {
-        delegate.disableRequesterPays(bucketName);
-    }
-
-    @Override
-    public boolean isRequesterPaysEnabled(String bucketName) throws AmazonServiceException, AmazonClientException {
-        return delegate.isRequesterPaysEnabled(bucketName);
-    }
-
-    @Override
-    public ObjectListing listNextBatchOfObjects(ListNextBatchOfObjectsRequest listNextBatchOfObjectsRequest) throws AmazonClientException,
-        AmazonServiceException {
-        return delegate.listNextBatchOfObjects(listNextBatchOfObjectsRequest);
-    }
-
-    @Override
-    public VersionListing listNextBatchOfVersions(ListNextBatchOfVersionsRequest listNextBatchOfVersionsRequest)
-        throws AmazonClientException, AmazonServiceException {
-        return delegate.listNextBatchOfVersions(listNextBatchOfVersionsRequest);
-    }
-
-    @Override
-    public Owner getS3AccountOwner(GetS3AccountOwnerRequest getS3AccountOwnerRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.getS3AccountOwner(getS3AccountOwnerRequest);
-    }
-
-    @Override
-    public BucketLoggingConfiguration getBucketLoggingConfiguration(
-        GetBucketLoggingConfigurationRequest getBucketLoggingConfigurationRequest
-    ) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketLoggingConfiguration(getBucketLoggingConfigurationRequest);
-    }
-
-    @Override
-    public BucketVersioningConfiguration getBucketVersioningConfiguration(
-        GetBucketVersioningConfigurationRequest getBucketVersioningConfigurationRequest
-    ) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketVersioningConfiguration(getBucketVersioningConfigurationRequest);
-    }
-
-    @Override
-    public BucketLifecycleConfiguration getBucketLifecycleConfiguration(
-        GetBucketLifecycleConfigurationRequest getBucketLifecycleConfigurationRequest
-    ) {
-        return delegate.getBucketLifecycleConfiguration(getBucketLifecycleConfigurationRequest);
-    }
-
-    @Override
-    public BucketCrossOriginConfiguration getBucketCrossOriginConfiguration(
-        GetBucketCrossOriginConfigurationRequest getBucketCrossOriginConfigurationRequest
-    ) {
-        return delegate.getBucketCrossOriginConfiguration(getBucketCrossOriginConfigurationRequest);
-    }
-
-    @Override
-    public BucketTaggingConfiguration getBucketTaggingConfiguration(
-        GetBucketTaggingConfigurationRequest getBucketTaggingConfigurationRequest
-    ) {
-        return delegate.getBucketTaggingConfiguration(getBucketTaggingConfigurationRequest);
-    }
-
-    @Override
-    public BucketNotificationConfiguration getBucketNotificationConfiguration(
-        GetBucketNotificationConfigurationRequest getBucketNotificationConfigurationRequest
-    ) throws AmazonClientException, AmazonServiceException {
-        return delegate.getBucketNotificationConfiguration(getBucketNotificationConfigurationRequest);
-    }
-
-    @Override
-    public BucketReplicationConfiguration getBucketReplicationConfiguration(
-        GetBucketReplicationConfigurationRequest getBucketReplicationConfigurationRequest
-    ) throws AmazonServiceException, AmazonClientException {
-        return delegate.getBucketReplicationConfiguration(getBucketReplicationConfigurationRequest);
-    }
-
-    @Override
-    public HeadBucketResult headBucket(HeadBucketRequest headBucketRequest) throws AmazonClientException, AmazonServiceException {
-        return delegate.headBucket(headBucketRequest);
-    }
-
-    @Override
-    public void shutdown() {
-        delegate.shutdown();
-    }
-}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AwsS3ServiceImplTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AwsS3ServiceImplTests.java
index 38d9ebf337731..b80b857644f2a 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AwsS3ServiceImplTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/AwsS3ServiceImplTests.java
@@ -32,34 +32,56 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.Protocol;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.retry.backoff.BackoffStrategy;
+import software.amazon.awssdk.http.apache.ProxyConfiguration;
+
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.repositories.s3.utils.Protocol;
+import org.junit.Before;
 
+import java.io.Closeable;
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 
+import static org.opensearch.repositories.s3.S3ClientSettings.PROTOCOL_SETTING;
+import static org.opensearch.repositories.s3.S3ClientSettings.PROXY_TYPE_SETTING;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
-import static org.opensearch.repositories.s3.S3ClientSettings.PROTOCOL_SETTING;
-import static org.opensearch.repositories.s3.S3ClientSettings.PROXY_TYPE_SETTING;
 
-public class AwsS3ServiceImplTests extends OpenSearchTestCase {
+public class AwsS3ServiceImplTests extends AbstractS3RepositoryTestCase {
 
-    public void testAWSCredentialsDefaultToInstanceProviders() {
+    private static final String HOST = "127.0.0.10";
+    private static final int PORT = 8080;
+
+    private Settings.Builder settingsBuilder;
+
+    @Override
+    @Before
+    @SuppressForbidden(reason = "Need to set system property here for AWS SDK v2")
+    public void setUp() throws Exception {
+        settingsBuilder = Settings.builder()
+            .put("s3.client.default.proxy.type", "http")
+            .put("s3.client.default.proxy.host", HOST)
+            .put("s3.client.default.proxy.port", PORT);
+        super.setUp();
+    }
+
+    public void testAwsCredentialsDefaultToInstanceProviders() {
         final String inexistentClientName = randomAlphaOfLength(8).toLowerCase(Locale.ROOT);
-        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(Settings.EMPTY, inexistentClientName);
-        final AWSCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, clientSettings);
+        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(Settings.EMPTY, inexistentClientName, configPath());
+        final AwsCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, clientSettings);
         assertThat(credentialsProvider, instanceOf(S3Service.PrivilegedInstanceProfileCredentialsProvider.class));
     }
 
-    public void testAWSCredentialsFromKeystore() {
+    public void testAwsCredentialsFromKeystore() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         final String clientNamePrefix = "some_client_name_";
         final int clientsCount = randomIntBetween(0, 4);
@@ -69,20 +91,115 @@ public void testAWSCredentialsFromKeystore() {
             secureSettings.setString("s3.client." + clientName + ".secret_key", clientName + "_aws_secret_key");
         }
         final Settings settings = Settings.builder().setSecureSettings(secureSettings).build();
-        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings);
+        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings, configPath());
+        // no less, no more
+        assertThat(allClientsSettings.size(), is(clientsCount + 1)); // including default
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            final S3ClientSettings someClientSettings = allClientsSettings.get(clientName);
+            final AwsCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, someClientSettings);
+            assertThat(credentialsProvider, instanceOf(StaticCredentialsProvider.class));
+            assertThat(credentialsProvider.resolveCredentials().accessKeyId(), is(clientName + "_aws_access_key"));
+            assertThat(credentialsProvider.resolveCredentials().secretAccessKey(), is(clientName + "_aws_secret_key"));
+        }
+        // test default exists and is an Instance provider
+        final S3ClientSettings defaultClientSettings = allClientsSettings.get("default");
+        final AwsCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
+        assertThat(defaultCredentialsProvider, instanceOf(S3Service.PrivilegedInstanceProfileCredentialsProvider.class));
+    }
+
+    public void testCredentialsAndIrsaWithIdentityTokenFileCredentialsFromKeystore() throws IOException {
+        final Map<String, String> plainSettings = new HashMap<>();
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        final String clientNamePrefix = "some_client_name_";
+        final int clientsCount = randomIntBetween(0, 4);
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            secureSettings.setString("s3.client." + clientName + ".role_arn", clientName + "_role_arn");
+
+            // Use static AWS credentials for tests
+            secureSettings.setString("s3.client." + clientName + ".access_key", clientName + "_aws_access_key");
+            secureSettings.setString("s3.client." + clientName + ".secret_key", clientName + "_aws_secret_key");
+
+            // Use explicit region setting
+            plainSettings.put("s3.client." + clientName + ".region", "us-east1");
+            plainSettings.put("s3.client." + clientName + ".identity_token_file", clientName + "_identity_token_file");
+        }
+        final Settings settings = Settings.builder().loadFromMap(plainSettings).setSecureSettings(secureSettings).build();
+        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings, configPath());
+        // no less, no more
+        assertThat(allClientsSettings.size(), is(clientsCount + 1)); // including default
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            final S3ClientSettings someClientSettings = allClientsSettings.get(clientName);
+            final AwsCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, someClientSettings);
+            assertThat(credentialsProvider, instanceOf(S3Service.PrivilegedSTSAssumeRoleSessionCredentialsProvider.class));
+            ((Closeable) credentialsProvider).close();
+        }
+        // test default exists and is an Instance provider
+        final S3ClientSettings defaultClientSettings = allClientsSettings.get("default");
+        final AwsCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
+        assertThat(defaultCredentialsProvider, instanceOf(S3Service.PrivilegedInstanceProfileCredentialsProvider.class));
+    }
+
+    public void testCredentialsAndIrsaCredentialsFromKeystore() throws IOException {
+        final Map<String, String> plainSettings = new HashMap<>();
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        final String clientNamePrefix = "some_client_name_";
+        final int clientsCount = randomIntBetween(0, 4);
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            secureSettings.setString("s3.client." + clientName + ".role_arn", clientName + "_role_arn");
+            secureSettings.setString("s3.client." + clientName + ".role_session_name", clientName + "_role_session_name");
+
+            // Use static AWS credentials for tests
+            secureSettings.setString("s3.client." + clientName + ".access_key", clientName + "_aws_access_key");
+            secureSettings.setString("s3.client." + clientName + ".secret_key", clientName + "_aws_secret_key");
+
+            // Use explicit region setting
+            plainSettings.put("s3.client." + clientName + ".region", "us-east1");
+        }
+        final Settings settings = Settings.builder().loadFromMap(plainSettings).setSecureSettings(secureSettings).build();
+        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings, configPath());
         // no less, no more
         assertThat(allClientsSettings.size(), is(clientsCount + 1)); // including default
         for (int i = 0; i < clientsCount; i++) {
             final String clientName = clientNamePrefix + i;
             final S3ClientSettings someClientSettings = allClientsSettings.get(clientName);
-            final AWSCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, someClientSettings);
-            assertThat(credentialsProvider, instanceOf(AWSStaticCredentialsProvider.class));
-            assertThat(credentialsProvider.getCredentials().getAWSAccessKeyId(), is(clientName + "_aws_access_key"));
-            assertThat(credentialsProvider.getCredentials().getAWSSecretKey(), is(clientName + "_aws_secret_key"));
+            final AwsCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, someClientSettings);
+            assertThat(credentialsProvider, instanceOf(S3Service.PrivilegedSTSAssumeRoleSessionCredentialsProvider.class));
+            ((Closeable) credentialsProvider).close();
         }
         // test default exists and is an Instance provider
         final S3ClientSettings defaultClientSettings = allClientsSettings.get("default");
-        final AWSCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
+        final AwsCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
+        assertThat(defaultCredentialsProvider, instanceOf(S3Service.PrivilegedInstanceProfileCredentialsProvider.class));
+    }
+
+    public void testIrsaCredentialsFromKeystore() throws IOException {
+        final Map<String, String> plainSettings = new HashMap<>();
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        final String clientNamePrefix = "some_client_name_";
+        final int clientsCount = randomIntBetween(0, 4);
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            secureSettings.setString("s3.client." + clientName + ".role_arn", clientName + "_role_arn");
+            secureSettings.setString("s3.client." + clientName + ".role_session_name", clientName + "_role_session_name");
+        }
+        final Settings settings = Settings.builder().loadFromMap(plainSettings).setSecureSettings(secureSettings).build();
+        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings, configPath());
+        // no less, no more
+        assertThat(allClientsSettings.size(), is(clientsCount + 1)); // including default
+        for (int i = 0; i < clientsCount; i++) {
+            final String clientName = clientNamePrefix + i;
+            final S3ClientSettings someClientSettings = allClientsSettings.get(clientName);
+            final AwsCredentialsProvider credentialsProvider = S3Service.buildCredentials(logger, someClientSettings);
+            assertThat(credentialsProvider, instanceOf(S3Service.PrivilegedSTSAssumeRoleSessionCredentialsProvider.class));
+            ((Closeable) credentialsProvider).close();
+        }
+        // test default exists and is an Instance provider
+        final S3ClientSettings defaultClientSettings = allClientsSettings.get("default");
+        final AwsCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
         assertThat(defaultCredentialsProvider, instanceOf(S3Service.PrivilegedInstanceProfileCredentialsProvider.class));
     }
 
@@ -93,14 +210,14 @@ public void testSetDefaultCredential() {
         secureSettings.setString("s3.client.default.access_key", awsAccessKey);
         secureSettings.setString("s3.client.default.secret_key", awsSecretKey);
         final Settings settings = Settings.builder().setSecureSettings(secureSettings).build();
-        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings);
+        final Map<String, S3ClientSettings> allClientsSettings = S3ClientSettings.load(settings, configPath());
         assertThat(allClientsSettings.size(), is(1));
         // test default exists and is an Instance provider
         final S3ClientSettings defaultClientSettings = allClientsSettings.get("default");
-        final AWSCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
-        assertThat(defaultCredentialsProvider, instanceOf(AWSStaticCredentialsProvider.class));
-        assertThat(defaultCredentialsProvider.getCredentials().getAWSAccessKeyId(), is(awsAccessKey));
-        assertThat(defaultCredentialsProvider.getCredentials().getAWSSecretKey(), is(awsSecretKey));
+        final AwsCredentialsProvider defaultCredentialsProvider = S3Service.buildCredentials(logger, defaultClientSettings);
+        assertThat(defaultCredentialsProvider, instanceOf(StaticCredentialsProvider.class));
+        assertThat(defaultCredentialsProvider.resolveCredentials().accessKeyId(), is(awsAccessKey));
+        assertThat(defaultCredentialsProvider.resolveCredentials().secretAccessKey(), is(awsSecretKey));
     }
 
     public void testCredentialsIncomplete() {
@@ -113,7 +230,7 @@ public void testCredentialsIncomplete() {
             secureSettings.setString("s3.client." + clientName + ".secret_key", "aws_secret_key");
         }
         final Settings settings = Settings.builder().setSecureSettings(secureSettings).build();
-        final Exception e = expectThrows(IllegalArgumentException.class, () -> S3ClientSettings.load(settings));
+        final Exception e = expectThrows(IllegalArgumentException.class, () -> S3ClientSettings.load(settings, configPath()));
         if (missingOrMissing) {
             assertThat(e.getMessage(), containsString("Missing secret key for s3 client [" + clientName + "]"));
         } else {
@@ -122,16 +239,8 @@ public void testCredentialsIncomplete() {
     }
 
     public void testAWSDefaultConfiguration() {
-        launchAWSConfigurationTest(
-            Settings.EMPTY,
-            Protocol.HTTPS,
-            null,
-            -1,
-            null,
-            null,
-            3,
-            ClientConfiguration.DEFAULT_THROTTLE_RETRIES,
-            ClientConfiguration.DEFAULT_SOCKET_TIMEOUT
+        SocketAccess.doPrivilegedVoid(
+            () -> launchAWSConfigurationTest(Settings.EMPTY, Protocol.HTTPS, null, -1, null, null, 3, true, 50_000)
         );
     }
 
@@ -142,20 +251,22 @@ public void testAWSConfigurationWithAwsSettings() {
         final Settings settings = Settings.builder()
             .setSecureSettings(secureSettings)
             .put("s3.client.default.protocol", "http")
-            .put("s3.client.default.proxy.host", "127.0.0.10")
-            .put("s3.client.default.proxy.port", 8080)
+            .put("s3.client.default.proxy.host", HOST)
+            .put("s3.client.default.proxy.port", PORT)
             .put("s3.client.default.read_timeout", "10s")
             .build();
-        launchAWSConfigurationTest(
-            settings,
-            Protocol.HTTP,
-            "127.0.0.10",
-            8080,
-            "aws_proxy_username",
-            "aws_proxy_password",
-            3,
-            ClientConfiguration.DEFAULT_THROTTLE_RETRIES,
-            10000
+        SocketAccess.doPrivilegedVoid(
+            () -> launchAWSConfigurationTest(
+                settings,
+                Protocol.HTTP,
+                HOST,
+                PORT,
+                "aws_proxy_username",
+                "aws_proxy_password",
+                3,
+                true,
+                10000
+            )
         );
         assertWarnings(
             "Using of "
@@ -174,20 +285,22 @@ public void testProxyTypeOverrideProtocolSettings() {
             .setSecureSettings(secureSettings)
             .put("s3.client.default.protocol", "http")
             .put("s3.client.default.proxy.type", "https")
-            .put("s3.client.default.proxy.host", "127.0.0.10")
-            .put("s3.client.default.proxy.port", 8080)
+            .put("s3.client.default.proxy.host", HOST)
+            .put("s3.client.default.proxy.port", PORT)
             .put("s3.client.default.read_timeout", "10s")
             .build();
-        launchAWSConfigurationTest(
-            settings,
-            Protocol.HTTP,
-            "127.0.0.10",
-            8080,
-            "aws_proxy_username",
-            "aws_proxy_password",
-            3,
-            ClientConfiguration.DEFAULT_THROTTLE_RETRIES,
-            10000
+        SocketAccess.doPrivilegedVoid(
+            () -> launchAWSConfigurationTest(
+                settings,
+                Protocol.HTTP,
+                HOST,
+                PORT,
+                "aws_proxy_username",
+                "aws_proxy_password",
+                3,
+                true,
+                10000
+            )
         );
     }
 
@@ -198,31 +311,29 @@ public void testSocksProxyConfiguration() throws IOException {
         final Settings settings = Settings.builder()
             .setSecureSettings(secureSettings)
             .put("s3.client.default.proxy.type", "socks")
-            .put("s3.client.default.proxy.host", "127.0.0.10")
-            .put("s3.client.default.proxy.port", 8080)
+            .put("s3.client.default.proxy.host", HOST)
+            .put("s3.client.default.proxy.port", PORT)
             .put("s3.client.default.read_timeout", "10s")
             .build();
 
-        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, "default");
-        final ClientConfiguration configuration = S3Service.buildConfiguration(clientSettings);
+        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, "default", configPath());
+        final ProxyConfiguration configuration = S3Service.buildHttpProxyConfiguration(clientSettings);
 
-        assertEquals(Protocol.HTTPS, configuration.getProtocol());
-        assertEquals(Protocol.HTTP, configuration.getProxyProtocol()); // default value in SDK
-        assertEquals(-1, configuration.getProxyPort());
-        assertNull(configuration.getProxyUsername());
-        assertNull(configuration.getProxyPassword());
+        assertEquals(0, configuration.port());
+        assertNull(configuration.username());
+        assertNull(configuration.password());
     }
 
     public void testRepositoryMaxRetries() {
-        final Settings settings = Settings.builder().put("s3.client.default.max_retries", 5).build();
-        launchAWSConfigurationTest(settings, Protocol.HTTPS, null, -1, null, null, 5, ClientConfiguration.DEFAULT_THROTTLE_RETRIES, 50000);
+        final Settings settings = settingsBuilder.put("s3.client.default.max_retries", 5).build();
+        SocketAccess.doPrivilegedVoid(() -> launchAWSConfigurationTest(settings, Protocol.HTTPS, HOST, PORT, "", "", 5, true, 50000));
     }
 
     public void testRepositoryThrottleRetries() {
         final boolean throttling = randomBoolean();
 
-        final Settings settings = Settings.builder().put("s3.client.default.use_throttle_retries", throttling).build();
-        launchAWSConfigurationTest(settings, Protocol.HTTPS, null, -1, null, null, 3, throttling, 50000);
+        final Settings settings = settingsBuilder.put("s3.client.default.use_throttle_retries", throttling).build();
+        SocketAccess.doPrivilegedVoid(() -> launchAWSConfigurationTest(settings, Protocol.HTTPS, HOST, PORT, "", "", 3, throttling, 50000));
     }
 
     private void launchAWSConfigurationTest(
@@ -237,18 +348,28 @@ private void launchAWSConfigurationTest(
         int expectedReadTimeout
     ) {
 
-        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, "default");
-        final ClientConfiguration configuration = S3Service.buildConfiguration(clientSettings);
-
-        assertThat(configuration.getResponseMetadataCacheSize(), is(0));
-        assertThat(configuration.getProtocol(), is(expectedProtocol));
-        assertThat(configuration.getProxyHost(), is(expectedProxyHost));
-        assertThat(configuration.getProxyPort(), is(expectedProxyPort));
-        assertThat(configuration.getProxyUsername(), is(expectedProxyUsername));
-        assertThat(configuration.getProxyPassword(), is(expectedProxyPassword));
-        assertThat(configuration.getMaxErrorRetry(), is(expectedMaxRetries));
-        assertThat(configuration.useThrottledRetries(), is(expectedUseThrottleRetries));
-        assertThat(configuration.getSocketTimeout(), is(expectedReadTimeout));
+        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, "default", configPath());
+        if (clientSettings.proxySettings != ProxySettings.NO_PROXY_SETTINGS) {
+            final ProxyConfiguration proxyConfiguration = S3Service.buildHttpProxyConfiguration(clientSettings);
+            assertThat(proxyConfiguration.host(), is(expectedProxyHost));
+            assertThat(proxyConfiguration.port(), is(expectedProxyPort));
+            assertThat(proxyConfiguration.username(), is(expectedProxyUsername));
+            assertThat(proxyConfiguration.password(), is(expectedProxyPassword));
+        }
+
+        final ClientOverrideConfiguration clientOverrideConfiguration = S3Service.buildOverrideConfiguration(clientSettings);
+
+        assertTrue(clientOverrideConfiguration.retryPolicy().isPresent());
+        assertThat(clientOverrideConfiguration.retryPolicy().get().numRetries(), is(expectedMaxRetries));
+        if (expectedUseThrottleRetries) {
+            assertThat(
+                clientOverrideConfiguration.retryPolicy().get().throttlingBackoffStrategy(),
+                is(BackoffStrategy.defaultThrottlingStrategy())
+            );
+        } else {
+            assertThat(clientOverrideConfiguration.retryPolicy().get().throttlingBackoffStrategy(), is(BackoffStrategy.none()));
+        }
+        // assertThat(proxyConfiguration.getSocketTimeout(), is(expectedReadTimeout));
     }
 
     public void testEndpointSetting() {
@@ -258,8 +379,7 @@ public void testEndpointSetting() {
 
     private void assertEndpoint(Settings repositorySettings, Settings settings, String expectedEndpoint) {
         final String configName = S3Repository.CLIENT_NAME.get(repositorySettings);
-        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, configName);
+        final S3ClientSettings clientSettings = S3ClientSettings.getClientSettings(settings, configName, configPath());
         assertThat(clientSettings.endpoint, is(expectedEndpoint));
     }
-
 }
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/ConfigPathSupport.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/ConfigPathSupport.java
new file mode 100644
index 0000000000000..890dd245c67fd
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/ConfigPathSupport.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import org.opensearch.common.io.PathUtils;
+
+import java.nio.file.Path;
+
+/**
+ * The trait that adds the config path to the test cases
+ */
+interface ConfigPathSupport {
+    default Path configPath() {
+        return PathUtils.get("config");
+    }
+}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/RepositoryCredentialsTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/RepositoryCredentialsTests.java
index 9c359d67db88b..a4bfe11383b4f 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/RepositoryCredentialsTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/RepositoryCredentialsTests.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.auth.AWSCredentials;
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.services.s3.AmazonS3;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
+import software.amazon.awssdk.services.s3.DelegatingS3Client;
+import software.amazon.awssdk.services.s3.S3Client;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
@@ -45,7 +46,7 @@
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.PluginsService;
@@ -57,6 +58,7 @@
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 
+import java.nio.file.Path;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.Collection;
@@ -74,7 +76,7 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @SuppressForbidden(reason = "test requires to set a System property to allow insecure settings when running in IDE")
-public class RepositoryCredentialsTests extends OpenSearchSingleNodeTestCase {
+public class RepositoryCredentialsTests extends OpenSearchSingleNodeTestCase implements ConfigPathSupport {
 
     static {
         AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
@@ -106,6 +108,7 @@ protected Settings nodeSettings() {
     }
 
     public void testRepositoryCredentialsOverrideSecureCredentials() {
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
         final String repositoryName = "repo-creds-override";
         final Settings.Builder repositorySettings = Settings.builder()
             // repository settings for credentials override node secure settings
@@ -123,12 +126,14 @@ public void testRepositoryCredentialsOverrideSecureCredentials() {
         assertThat(repositories.repository(repositoryName), instanceOf(S3Repository.class));
 
         final S3Repository repository = (S3Repository) repositories.repository(repositoryName);
-        final AmazonS3 client = repository.createBlobStore().clientReference().get();
-        assertThat(client, instanceOf(ProxyS3RepositoryPlugin.ClientAndCredentials.class));
+        try (final AmazonS3Reference clientReference = repository.createBlobStore().clientReference()) {
+            S3Client client = clientReference.get();
+            assertThat(client, instanceOf(ProxyS3RepositoryPlugin.ClientAndCredentials.class));
 
-        final AWSCredentials credentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.getCredentials();
-        assertThat(credentials.getAWSAccessKeyId(), is("insecure_aws_key"));
-        assertThat(credentials.getAWSSecretKey(), is("insecure_aws_secret"));
+            final AwsCredentials credentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.resolveCredentials();
+            assertThat(credentials.accessKeyId(), is("insecure_aws_key"));
+            assertThat(credentials.secretAccessKey(), is("insecure_aws_secret"));
+        }
 
         assertWarnings(
             "[secret_key] setting was deprecated in OpenSearch and will be removed in a future release!"
@@ -141,6 +146,7 @@ public void testRepositoryCredentialsOverrideSecureCredentials() {
     }
 
     public void testReinitSecureCredentials() {
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
         final String clientName = randomFrom("default", "other");
 
         final Settings.Builder repositorySettings = Settings.builder();
@@ -162,19 +168,19 @@ public void testReinitSecureCredentials() {
 
         final S3Repository repository = (S3Repository) repositories.repository(repositoryName);
         try (AmazonS3Reference clientReference = ((S3BlobStore) repository.blobStore()).clientReference()) {
-            final AmazonS3 client = clientReference.get();
+            final S3Client client = clientReference.get();
             assertThat(client, instanceOf(ProxyS3RepositoryPlugin.ClientAndCredentials.class));
 
-            final AWSCredentials credentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.getCredentials();
+            final AwsCredentials credentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.resolveCredentials();
             if (hasInsecureSettings) {
-                assertThat(credentials.getAWSAccessKeyId(), is("insecure_aws_key"));
-                assertThat(credentials.getAWSSecretKey(), is("insecure_aws_secret"));
+                assertThat(credentials.accessKeyId(), is("insecure_aws_key"));
+                assertThat(credentials.secretAccessKey(), is("insecure_aws_secret"));
             } else if ("other".equals(clientName)) {
-                assertThat(credentials.getAWSAccessKeyId(), is("secure_other_key"));
-                assertThat(credentials.getAWSSecretKey(), is("secure_other_secret"));
+                assertThat(credentials.accessKeyId(), is("secure_other_key"));
+                assertThat(credentials.secretAccessKey(), is("secure_other_secret"));
             } else {
-                assertThat(credentials.getAWSAccessKeyId(), is("secure_default_key"));
-                assertThat(credentials.getAWSSecretKey(), is("secure_default_secret"));
+                assertThat(credentials.accessKeyId(), is("secure_default_key"));
+                assertThat(credentials.secretAccessKey(), is("secure_default_secret"));
             }
 
             // new settings
@@ -189,29 +195,29 @@ public void testReinitSecureCredentials() {
 
             // check the not-yet-closed client reference still has the same credentials
             if (hasInsecureSettings) {
-                assertThat(credentials.getAWSAccessKeyId(), is("insecure_aws_key"));
-                assertThat(credentials.getAWSSecretKey(), is("insecure_aws_secret"));
+                assertThat(credentials.accessKeyId(), is("insecure_aws_key"));
+                assertThat(credentials.secretAccessKey(), is("insecure_aws_secret"));
             } else if ("other".equals(clientName)) {
-                assertThat(credentials.getAWSAccessKeyId(), is("secure_other_key"));
-                assertThat(credentials.getAWSSecretKey(), is("secure_other_secret"));
+                assertThat(credentials.accessKeyId(), is("secure_other_key"));
+                assertThat(credentials.secretAccessKey(), is("secure_other_secret"));
             } else {
-                assertThat(credentials.getAWSAccessKeyId(), is("secure_default_key"));
-                assertThat(credentials.getAWSSecretKey(), is("secure_default_secret"));
+                assertThat(credentials.accessKeyId(), is("secure_default_key"));
+                assertThat(credentials.secretAccessKey(), is("secure_default_secret"));
             }
         }
 
         // check credentials have been updated
         try (AmazonS3Reference clientReference = ((S3BlobStore) repository.blobStore()).clientReference()) {
-            final AmazonS3 client = clientReference.get();
+            final S3Client client = clientReference.get();
             assertThat(client, instanceOf(ProxyS3RepositoryPlugin.ClientAndCredentials.class));
 
-            final AWSCredentials newCredentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.getCredentials();
+            final AwsCredentials newCredentials = ((ProxyS3RepositoryPlugin.ClientAndCredentials) client).credentials.resolveCredentials();
             if (hasInsecureSettings) {
-                assertThat(newCredentials.getAWSAccessKeyId(), is("insecure_aws_key"));
-                assertThat(newCredentials.getAWSSecretKey(), is("insecure_aws_secret"));
+                assertThat(newCredentials.accessKeyId(), is("insecure_aws_key"));
+                assertThat(newCredentials.secretAccessKey(), is("insecure_aws_secret"));
             } else {
-                assertThat(newCredentials.getAWSAccessKeyId(), is("new_secret_aws_key"));
-                assertThat(newCredentials.getAWSSecretKey(), is("new_secret_aws_secret"));
+                assertThat(newCredentials.accessKeyId(), is("new_secret_aws_key"));
+                assertThat(newCredentials.secretAccessKey(), is("new_secret_aws_secret"));
             }
         }
 
@@ -228,6 +234,7 @@ public void testReinitSecureCredentials() {
     }
 
     public void testInsecureRepositoryCredentials() throws Exception {
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
         final String repositoryName = "repo-insecure-creds";
         createRepository(
             repositoryName,
@@ -284,8 +291,8 @@ private void createRepository(final String name, final Settings repositorySettin
      */
     public static final class ProxyS3RepositoryPlugin extends S3RepositoryPlugin {
 
-        public ProxyS3RepositoryPlugin(Settings settings) {
-            super(settings, new ProxyS3Service());
+        public ProxyS3RepositoryPlugin(Settings settings, Path configPath) {
+            super(settings, configPath, new ProxyS3Service(configPath), new S3AsyncService(configPath));
         }
 
         @Override
@@ -295,7 +302,7 @@ protected S3Repository createRepository(
             ClusterService clusterService,
             RecoverySettings recoverySettings
         ) {
-            return new S3Repository(metadata, registry, service, clusterService, recoverySettings) {
+            return new S3Repository(metadata, registry, service, clusterService, recoverySettings, null, null, null, null, false) {
                 @Override
                 protected void assertSnapshotOrGenericThread() {
                     // eliminate thread name check as we create repo manually on test/main threads
@@ -303,10 +310,10 @@ protected void assertSnapshotOrGenericThread() {
             };
         }
 
-        public static final class ClientAndCredentials extends AmazonS3Wrapper {
-            final AWSCredentialsProvider credentials;
+        public static final class ClientAndCredentials extends DelegatingS3Client {
+            final AwsCredentialsProvider credentials;
 
-            ClientAndCredentials(AmazonS3 delegate, AWSCredentialsProvider credentials) {
+            ClientAndCredentials(S3Client delegate, AwsCredentialsProvider credentials) {
                 super(delegate);
                 this.credentials = credentials;
             }
@@ -316,10 +323,15 @@ public static final class ProxyS3Service extends S3Service {
 
             private static final Logger logger = LogManager.getLogger(ProxyS3Service.class);
 
+            ProxyS3Service(final Path configPath) {
+                super(configPath);
+            }
+
             @Override
-            AmazonS3 buildClient(final S3ClientSettings clientSettings) {
-                final AmazonS3 client = super.buildClient(clientSettings);
-                return new ClientAndCredentials(client, buildCredentials(logger, clientSettings));
+            AmazonS3WithCredentials buildClient(final S3ClientSettings clientSettings) {
+                final AmazonS3WithCredentials client = SocketAccess.doPrivileged(() -> super.buildClient(clientSettings));
+                final AwsCredentialsProvider credentials = buildCredentials(logger, clientSettings);
+                return AmazonS3WithCredentials.create(new ClientAndCredentials(client.client(), credentials), credentials);
             }
 
         }
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3AsyncServiceTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3AsyncServiceTests.java
new file mode 100644
index 0000000000000..e9fe557ab751a
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3AsyncServiceTests.java
@@ -0,0 +1,95 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import org.opensearch.cli.SuppressForbidden;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.settings.MockSecureSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferEventLoopGroup;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.Map;
+import java.util.concurrent.Executors;
+
+public class S3AsyncServiceTests extends OpenSearchTestCase implements ConfigPathSupport {
+
+    @Override
+    @Before
+    @SuppressForbidden(reason = "Need to set opensearch.path.conf for async client")
+    public void setUp() throws Exception {
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
+        super.setUp();
+    }
+
+    public void testCachedClientsAreReleased() {
+        final S3AsyncService s3AsyncService = new S3AsyncService(configPath());
+        final Settings settings = Settings.builder().put("endpoint", "http://first").put("region", "us-east-2").build();
+        final RepositoryMetadata metadata1 = new RepositoryMetadata("first", "s3", settings);
+        final RepositoryMetadata metadata2 = new RepositoryMetadata("second", "s3", settings);
+        final AsyncExecutorContainer asyncExecutorContainer = new AsyncExecutorContainer(
+            Executors.newSingleThreadExecutor(),
+            Executors.newSingleThreadExecutor(),
+            new AsyncTransferEventLoopGroup(1)
+        );
+        final S3ClientSettings clientSettings = s3AsyncService.settings(metadata2);
+        final S3ClientSettings otherClientSettings = s3AsyncService.settings(metadata2);
+        assertSame(clientSettings, otherClientSettings);
+        final AmazonAsyncS3Reference reference = SocketAccess.doPrivileged(
+            () -> s3AsyncService.client(metadata1, asyncExecutorContainer, asyncExecutorContainer)
+        );
+        reference.close();
+        s3AsyncService.close();
+        final AmazonAsyncS3Reference referenceReloaded = SocketAccess.doPrivileged(
+            () -> s3AsyncService.client(metadata1, asyncExecutorContainer, asyncExecutorContainer)
+        );
+        assertNotSame(referenceReloaded, reference);
+        referenceReloaded.close();
+        s3AsyncService.close();
+        final S3ClientSettings clientSettingsReloaded = s3AsyncService.settings(metadata1);
+        assertNotSame(clientSettings, clientSettingsReloaded);
+    }
+
+    public void testCachedClientsWithCredentialsAreReleased() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        final Map<String, S3ClientSettings> defaults = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).put("s3.client.default.identity_token_file", "file").build(),
+            configPath()
+        );
+        final S3AsyncService s3AsyncService = new S3AsyncService(configPath());
+        s3AsyncService.refreshAndClearCache(defaults);
+        final Settings settings = Settings.builder().put("endpoint", "http://first").put("region", "us-east-2").build();
+        final RepositoryMetadata metadata1 = new RepositoryMetadata("first", "s3", settings);
+        final RepositoryMetadata metadata2 = new RepositoryMetadata("second", "s3", settings);
+        final AsyncExecutorContainer asyncExecutorContainer = new AsyncExecutorContainer(
+            Executors.newSingleThreadExecutor(),
+            Executors.newSingleThreadExecutor(),
+            new AsyncTransferEventLoopGroup(1)
+        );
+        final S3ClientSettings clientSettings = s3AsyncService.settings(metadata2);
+        final S3ClientSettings otherClientSettings = s3AsyncService.settings(metadata2);
+        assertSame(clientSettings, otherClientSettings);
+        final AmazonAsyncS3Reference reference = SocketAccess.doPrivileged(
+            () -> s3AsyncService.client(metadata1, asyncExecutorContainer, asyncExecutorContainer)
+        );
+        reference.close();
+        s3AsyncService.close();
+        final AmazonAsyncS3Reference referenceReloaded = SocketAccess.doPrivileged(
+            () -> s3AsyncService.client(metadata1, asyncExecutorContainer, asyncExecutorContainer)
+        );
+        assertNotSame(referenceReloaded, reference);
+        referenceReloaded.close();
+        s3AsyncService.close();
+        final S3ClientSettings clientSettingsReloaded = s3AsyncService.settings(metadata1);
+        assertNotSame(clientSettings, clientSettingsReloaded);
+    }
+}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerMockClientTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerMockClientTests.java
new file mode 100644
index 0000000000000..8c8524212e08e
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerMockClientTests.java
@@ -0,0 +1,544 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3;
+
+import software.amazon.awssdk.core.async.AsyncRequestBody;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
+import software.amazon.awssdk.services.s3.model.DeleteObjectResponse;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectResponse;
+import software.amazon.awssdk.services.s3.model.UploadPartRequest;
+import software.amazon.awssdk.services.s3.model.UploadPartResponse;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.CheckedTriFunction;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.stream.write.StreamContextSupplier;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeIndexInputStream;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferEventLoopGroup;
+import org.opensearch.repositories.s3.async.AsyncTransferManager;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.mockito.invocation.InvocationOnMock;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+public class S3BlobContainerMockClientTests extends OpenSearchTestCase implements ConfigPathSupport {
+
+    private MockS3AsyncService asyncService;
+    private ExecutorService futureCompletionService;
+    private ExecutorService streamReaderService;
+    private AsyncTransferEventLoopGroup transferNIOGroup;
+    private S3BlobContainer blobContainer;
+
+    static class MockS3AsyncService extends S3AsyncService {
+
+        private final S3AsyncClient asyncClient = mock(S3AsyncClient.class);
+        private final int maxDelayInFutureCompletionMillis;
+
+        private boolean failPutObjectRequest;
+        private boolean failCreateMultipartUploadRequest;
+        private boolean failUploadPartRequest;
+        private boolean failCompleteMultipartUploadRequest;
+
+        private String multipartUploadId;
+
+        public MockS3AsyncService(Path configPath, int maxDelayInFutureCompletionMillis) {
+            super(configPath);
+            this.maxDelayInFutureCompletionMillis = maxDelayInFutureCompletionMillis;
+        }
+
+        public void initializeMocks(
+            boolean failPutObjectRequest,
+            boolean failCreateMultipartUploadRequest,
+            boolean failUploadPartRequest,
+            boolean failCompleteMultipartUploadRequest
+        ) {
+            setupFailureBooleans(
+                failPutObjectRequest,
+                failCreateMultipartUploadRequest,
+                failUploadPartRequest,
+                failCompleteMultipartUploadRequest
+            );
+            doAnswer(this::doOnPutObject).when(asyncClient).putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class));
+            doAnswer(this::doOnDeleteObject).when(asyncClient).deleteObject(any(DeleteObjectRequest.class));
+            doAnswer(this::doOnCreateMultipartUpload).when(asyncClient).createMultipartUpload(any(CreateMultipartUploadRequest.class));
+            doAnswer(this::doOnPartUpload).when(asyncClient).uploadPart(any(UploadPartRequest.class), any(AsyncRequestBody.class));
+            doAnswer(this::doOnCompleteMultipartUpload).when(asyncClient)
+                .completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
+            doAnswer(this::doOnAbortMultipartUpload).when(asyncClient).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
+        }
+
+        private void setupFailureBooleans(
+            boolean failPutObjectRequest,
+            boolean failCreateMultipartUploadRequest,
+            boolean failUploadPartRequest,
+            boolean failCompleteMultipartUploadRequest
+        ) {
+            this.failPutObjectRequest = failPutObjectRequest;
+            this.failCreateMultipartUploadRequest = failCreateMultipartUploadRequest;
+            this.failUploadPartRequest = failUploadPartRequest;
+            this.failCompleteMultipartUploadRequest = failCompleteMultipartUploadRequest;
+        }
+
+        private CompletableFuture<PutObjectResponse> doOnPutObject(InvocationOnMock invocationOnMock) {
+            CompletableFuture<PutObjectResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                if (failPutObjectRequest) {
+                    completableFuture.completeExceptionally(new IOException());
+                } else {
+                    completableFuture.complete(PutObjectResponse.builder().build());
+                }
+            }).start();
+
+            return completableFuture;
+        }
+
+        private CompletableFuture<DeleteObjectResponse> doOnDeleteObject(InvocationOnMock invocationOnMock) {
+            CompletableFuture<DeleteObjectResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                if (failPutObjectRequest) {
+                    completableFuture.completeExceptionally(new IOException());
+                } else {
+                    completableFuture.complete(DeleteObjectResponse.builder().build());
+                }
+            }).start();
+
+            return completableFuture;
+        }
+
+        private CompletableFuture<CreateMultipartUploadResponse> doOnCreateMultipartUpload(InvocationOnMock invocationOnMock) {
+            multipartUploadId = randomAlphaOfLength(5);
+            CompletableFuture<CreateMultipartUploadResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                if (failCreateMultipartUploadRequest) {
+                    completableFuture.completeExceptionally(new IOException());
+                } else {
+                    completableFuture.complete(CreateMultipartUploadResponse.builder().uploadId(multipartUploadId).build());
+                }
+            }).start();
+
+            return completableFuture;
+        }
+
+        private CompletableFuture<UploadPartResponse> doOnPartUpload(InvocationOnMock invocationOnMock) {
+            UploadPartRequest uploadPartRequest = invocationOnMock.getArgument(0);
+            assertEquals(multipartUploadId, uploadPartRequest.uploadId());
+            CompletableFuture<UploadPartResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                if (failUploadPartRequest) {
+                    completableFuture.completeExceptionally(new IOException());
+                } else {
+                    completableFuture.complete(UploadPartResponse.builder().eTag("eTag").build());
+                }
+            }).start();
+
+            return completableFuture;
+        }
+
+        private CompletableFuture<CompleteMultipartUploadResponse> doOnCompleteMultipartUpload(InvocationOnMock invocationOnMock) {
+            CompleteMultipartUploadRequest completeMultipartUploadRequest = invocationOnMock.getArgument(0);
+            assertEquals(multipartUploadId, completeMultipartUploadRequest.uploadId());
+            CompletableFuture<CompleteMultipartUploadResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                if (failCompleteMultipartUploadRequest) {
+                    completableFuture.completeExceptionally(new IOException());
+                } else {
+                    completableFuture.complete(CompleteMultipartUploadResponse.builder().build());
+                }
+            }).start();
+
+            return completableFuture;
+        }
+
+        private CompletableFuture<AbortMultipartUploadResponse> doOnAbortMultipartUpload(InvocationOnMock invocationOnMock) {
+            AbortMultipartUploadRequest abortMultipartUploadRequest = invocationOnMock.getArgument(0);
+            assertEquals(multipartUploadId, abortMultipartUploadRequest.uploadId());
+            CompletableFuture<AbortMultipartUploadResponse> completableFuture = new CompletableFuture<>();
+            new Thread(() -> {
+                try {
+                    Thread.sleep(randomInt(maxDelayInFutureCompletionMillis));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                completableFuture.complete(AbortMultipartUploadResponse.builder().build());
+
+            }).start();
+
+            return completableFuture;
+        }
+
+        public void verifyMultipartUploadCallCount(int numberOfParts, boolean finalizeUploadFailure) {
+            verify(asyncClient, times(1)).createMultipartUpload(any(CreateMultipartUploadRequest.class));
+            verify(asyncClient, times(!failCreateMultipartUploadRequest ? numberOfParts : 0)).uploadPart(
+                any(UploadPartRequest.class),
+                any(AsyncRequestBody.class)
+            );
+            verify(asyncClient, times(!failCreateMultipartUploadRequest && !failUploadPartRequest && !finalizeUploadFailure ? 1 : 0))
+                .completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
+            verify(
+                asyncClient,
+                times(
+                    (!failCreateMultipartUploadRequest && (failUploadPartRequest || failCompleteMultipartUploadRequest))
+                        || finalizeUploadFailure ? 1 : 0
+                )
+            ).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
+        }
+
+        public void verifySingleChunkUploadCallCount(boolean finalizeUploadFailure) {
+            verify(asyncClient, times(1)).putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class));
+            verify(asyncClient, times(finalizeUploadFailure ? 1 : 0)).deleteObject(any(DeleteObjectRequest.class));
+        }
+
+        @Override
+        public AmazonAsyncS3Reference client(
+            RepositoryMetadata repositoryMetadata,
+            AsyncExecutorContainer priorityExecutorBuilder,
+            AsyncExecutorContainer normalExecutorBuilder
+        ) {
+            return new AmazonAsyncS3Reference(AmazonAsyncS3WithCredentials.create(asyncClient, asyncClient, null));
+        }
+    }
+
+    /**
+     * An IndexInput implementation that serves only zeroes
+     */
+    static class ZeroIndexInput extends IndexInput {
+
+        private final AtomicBoolean closed = new AtomicBoolean(false);
+        private final AtomicLong reads = new AtomicLong(0);
+        private final long length;
+
+        /**
+         * @param resourceDescription resourceDescription should be a non-null, opaque string describing this resource; it's returned
+         *                            from {@link #toString}.
+         */
+        public ZeroIndexInput(String resourceDescription, final long length) {
+            super(resourceDescription);
+            this.length = length;
+        }
+
+        @Override
+        public void close() throws IOException {
+            closed.set(true);
+        }
+
+        @Override
+        public long getFilePointer() {
+            return reads.get();
+        }
+
+        @Override
+        public void seek(long pos) throws IOException {
+            reads.set(pos);
+        }
+
+        @Override
+        public long length() {
+            return length;
+        }
+
+        @Override
+        public IndexInput slice(String sliceDescription, long offset, long length) throws IOException {
+            return new ZeroIndexInput(sliceDescription, length);
+        }
+
+        @Override
+        public byte readByte() throws IOException {
+            ensureOpen();
+            return (byte) ((reads.incrementAndGet() <= length) ? 0 : -1);
+        }
+
+        @Override
+        public void readBytes(byte[] b, int offset, int len) throws IOException {
+            ensureOpen();
+            final long available = available();
+            final int toCopy = Math.min(len, (int) available);
+            Arrays.fill(b, offset, offset + toCopy, (byte) 0);
+            reads.addAndGet(toCopy);
+        }
+
+        private long available() {
+            return Math.max(length - reads.get(), 0);
+        }
+
+        private void ensureOpen() throws IOException {
+            if (closed.get()) {
+                throw new IOException("Stream closed");
+            }
+        }
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        asyncService = new MockS3AsyncService(configPath(), 1000);
+        futureCompletionService = Executors.newSingleThreadExecutor();
+        streamReaderService = Executors.newSingleThreadExecutor();
+        transferNIOGroup = new AsyncTransferEventLoopGroup(1);
+        blobContainer = createBlobContainer();
+        super.setUp();
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        IOUtils.close(asyncService);
+        super.tearDown();
+    }
+
+    private S3BlobContainer createBlobContainer() {
+        return new S3BlobContainer(BlobPath.cleanPath(), createBlobStore());
+    }
+
+    private S3BlobStore createBlobStore() {
+        final String clientName = randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+
+        final RepositoryMetadata repositoryMetadata = new RepositoryMetadata(
+            "repository",
+            S3Repository.TYPE,
+            Settings.builder().put(S3Repository.CLIENT_NAME.getKey(), clientName).build()
+        );
+
+        AsyncExecutorContainer asyncExecutorContainer = new AsyncExecutorContainer(
+            futureCompletionService,
+            streamReaderService,
+            transferNIOGroup
+        );
+
+        return new S3BlobStore(
+            null,
+            asyncService,
+            true,
+            "bucket",
+            S3Repository.SERVER_SIDE_ENCRYPTION_SETTING.getDefault(Settings.EMPTY),
+            S3Repository.BUFFER_SIZE_SETTING.getDefault(Settings.EMPTY),
+            S3Repository.CANNED_ACL_SETTING.getDefault(Settings.EMPTY),
+            S3Repository.STORAGE_CLASS_SETTING.getDefault(Settings.EMPTY),
+            repositoryMetadata,
+            new AsyncTransferManager(
+                S3Repository.PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING.getDefault(Settings.EMPTY).getBytes(),
+                asyncExecutorContainer.getStreamReader(),
+                asyncExecutorContainer.getStreamReader()
+            ),
+            asyncExecutorContainer,
+            asyncExecutorContainer
+        );
+    }
+
+    public void testWriteBlobByStreamsNoFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, false, false, false);
+        testWriteBlobByStreamsLargeBlob(false, false);
+    }
+
+    public void testWriteBlobByStreamsFinalizeUploadFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, false, false, false);
+        testWriteBlobByStreamsLargeBlob(false, true);
+    }
+
+    public void testWriteBlobByStreamsCreateMultipartRequestFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, true, false, false);
+        testWriteBlobByStreamsLargeBlob(true, false);
+    }
+
+    public void testWriteBlobByStreamsUploadPartRequestFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, false, true, false);
+        testWriteBlobByStreamsLargeBlob(true, false);
+    }
+
+    public void testWriteBlobByStreamsCompleteMultipartRequestFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, false, false, true);
+        testWriteBlobByStreamsLargeBlob(true, false);
+    }
+
+    public void testWriteBlobByStreamsSingleChunkUploadNoFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(false, false, false, false);
+        testWriteBlobByStreams(false, false);
+    }
+
+    public void testWriteBlobByStreamsSingleChunkUploadPutObjectFailure() throws IOException, ExecutionException, InterruptedException {
+        asyncService.initializeMocks(true, false, false, false);
+        testWriteBlobByStreams(true, false);
+    }
+
+    public void testWriteBlobByStreamsSingleChunkUploadFinalizeUploadFailure() throws IOException, ExecutionException,
+        InterruptedException {
+        asyncService.initializeMocks(false, false, false, false);
+        testWriteBlobByStreams(false, true);
+    }
+
+    private void testWriteBlobByStreams(boolean expectException, boolean throwExceptionOnFinalizeUpload) throws IOException,
+        ExecutionException, InterruptedException {
+        final byte[] bytes = randomByteArrayOfLength(100);
+        List<InputStream> openInputStreams = new ArrayList<>();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        ActionListener<Void> completionListener = ActionListener.wrap(resp -> { countDownLatch.countDown(); }, ex -> {
+            exceptionRef.set(ex);
+            countDownLatch.countDown();
+        });
+        blobContainer.asyncBlobUpload(new WriteContext("write_blob_by_streams_max_retries", new StreamContextSupplier() {
+            @Override
+            public StreamContext supplyStreamContext(long partSize) {
+                return new StreamContext(new CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException>() {
+                    @Override
+                    public InputStreamContainer apply(Integer partNo, Long size, Long position) throws IOException {
+                        InputStream inputStream = new OffsetRangeIndexInputStream(new ByteArrayIndexInput("desc", bytes), size, position);
+                        openInputStreams.add(inputStream);
+                        return new InputStreamContainer(inputStream, size, position);
+                    }
+                }, partSize, calculateLastPartSize(bytes.length, partSize), calculateNumberOfParts(bytes.length, partSize));
+            }
+        }, bytes.length, false, WritePriority.NORMAL, uploadSuccess -> {
+            assertTrue(uploadSuccess);
+            if (throwExceptionOnFinalizeUpload) {
+                throw new RuntimeException();
+            }
+        }, false, null), completionListener);
+
+        assertTrue(countDownLatch.await(5000, TimeUnit.SECONDS));
+        // wait for completableFuture to finish
+        if (expectException || throwExceptionOnFinalizeUpload) {
+            assertNotNull(exceptionRef.get());
+        }
+
+        asyncService.verifySingleChunkUploadCallCount(throwExceptionOnFinalizeUpload);
+
+        openInputStreams.forEach(inputStream -> {
+            try {
+                inputStream.close();
+            } catch (IOException e) {
+                fail("Failure while closing open input streams");
+            }
+        });
+    }
+
+    private void testWriteBlobByStreamsLargeBlob(boolean expectException, boolean throwExceptionOnFinalizeUpload) throws IOException,
+        ExecutionException, InterruptedException {
+        final ByteSizeValue partSize = S3Repository.PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING.getDefault(Settings.EMPTY);
+
+        int numberOfParts = randomIntBetween(2, 5);
+        final long lastPartSize = randomLongBetween(10, 512);
+        final long blobSize = ((numberOfParts - 1) * partSize.getBytes()) + lastPartSize;
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        ActionListener<Void> completionListener = ActionListener.wrap(resp -> { countDownLatch.countDown(); }, ex -> {
+            exceptionRef.set(ex);
+            countDownLatch.countDown();
+        });
+        List<InputStream> openInputStreams = new ArrayList<>();
+        blobContainer.asyncBlobUpload(new WriteContext("write_large_blob", new StreamContextSupplier() {
+            @Override
+            public StreamContext supplyStreamContext(long partSize) {
+                return new StreamContext(new CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException>() {
+                    @Override
+                    public InputStreamContainer apply(Integer partNo, Long size, Long position) throws IOException {
+                        InputStream inputStream = new OffsetRangeIndexInputStream(new ZeroIndexInput("desc", blobSize), size, position);
+                        openInputStreams.add(inputStream);
+                        return new InputStreamContainer(inputStream, size, position);
+                    }
+                }, partSize, calculateLastPartSize(blobSize, partSize), calculateNumberOfParts(blobSize, partSize));
+            }
+        }, blobSize, false, WritePriority.HIGH, uploadSuccess -> {
+            assertTrue(uploadSuccess);
+            if (throwExceptionOnFinalizeUpload) {
+                throw new RuntimeException();
+            }
+        }, false, null), completionListener);
+
+        assertTrue(countDownLatch.await(5000, TimeUnit.SECONDS));
+        if (expectException || throwExceptionOnFinalizeUpload) {
+            assertNotNull(exceptionRef.get());
+        }
+
+        asyncService.verifyMultipartUploadCallCount(numberOfParts, throwExceptionOnFinalizeUpload);
+
+        openInputStreams.forEach(inputStream -> {
+            try {
+                inputStream.close();
+            } catch (IOException ex) {
+                logger.error("Error closing input stream");
+            }
+        });
+    }
+
+    private long calculateLastPartSize(long totalSize, long partSize) {
+        return totalSize % partSize == 0 ? partSize : totalSize % partSize;
+    }
+
+    private int calculateNumberOfParts(long contentLength, long partSize) {
+        return (int) ((contentLength % partSize) == 0 ? contentLength / partSize : (contentLength / partSize) + 1);
+    }
+}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerRetriesTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerRetriesTests.java
index 4f4ec0afcf9f4..ecad68474b601 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerRetriesTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobContainerRetriesTests.java
@@ -31,29 +31,45 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.SdkClientException;
-import com.amazonaws.services.s3.internal.MD5DigestCalculatingInputStream;
-import com.amazonaws.util.Base16;
+import software.amazon.awssdk.core.exception.SdkClientException;
+import software.amazon.awssdk.core.io.SdkDigestInputStream;
+import software.amazon.awssdk.utils.internal.Base16;
+
 import org.apache.http.HttpStatus;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.CheckedTriFunction;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.StreamContext;
 import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.blobstore.stream.write.StreamContextSupplier;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeIndexInputStream;
+import org.opensearch.common.hash.MessageDigests;
+import org.opensearch.common.io.InputStreamContainer;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
 import org.opensearch.common.lucene.store.InputStreamIndexInput;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.repositories.blobstore.AbstractBlobContainerRetriesTestCase;
+import org.opensearch.repositories.blobstore.ZeroInputStream;
+import org.opensearch.repositories.s3.async.AsyncExecutorContainer;
+import org.opensearch.repositories.s3.async.AsyncTransferEventLoopGroup;
+import org.opensearch.repositories.s3.async.AsyncTransferManager;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 
 import java.io.ByteArrayInputStream;
@@ -63,14 +79,22 @@
 import java.net.InetSocketAddress;
 import java.net.SocketTimeoutException;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static org.opensearch.repositories.s3.S3ClientSettings.DISABLE_CHUNKED_ENCODING;
 import static org.opensearch.repositories.s3.S3ClientSettings.ENDPOINT_SETTING;
 import static org.opensearch.repositories.s3.S3ClientSettings.MAX_RETRIES_SETTING;
 import static org.opensearch.repositories.s3.S3ClientSettings.READ_TIMEOUT_SETTING;
+import static org.opensearch.repositories.s3.S3ClientSettings.REGION;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -81,19 +105,43 @@
  * This class tests how a {@link S3BlobContainer} and its underlying AWS S3 client are retrying requests when reading or writing blobs.
  */
 @SuppressForbidden(reason = "use a http server")
-public class S3BlobContainerRetriesTests extends AbstractBlobContainerRetriesTestCase {
+public class S3BlobContainerRetriesTests extends AbstractBlobContainerRetriesTestCase implements ConfigPathSupport {
 
     private S3Service service;
+    private String previousOpenSearchPathConf;
+    private S3AsyncService asyncService;
+    private ExecutorService futureCompletionService;
+    private ExecutorService streamReaderService;
+    private AsyncTransferEventLoopGroup transferNIOGroup;
 
     @Before
     public void setUp() throws Exception {
-        service = new S3Service();
+        previousOpenSearchPathConf = SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
+        service = new S3Service(configPath());
+        asyncService = new S3AsyncService(configPath());
+
+        futureCompletionService = Executors.newSingleThreadExecutor();
+        streamReaderService = Executors.newSingleThreadExecutor();
+        transferNIOGroup = new AsyncTransferEventLoopGroup(1);
+
+        // needed by S3AsyncService
+        SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", configPath().toString()));
         super.setUp();
     }
 
     @After
     public void tearDown() throws Exception {
-        IOUtils.close(service);
+        IOUtils.close(service, asyncService);
+
+        streamReaderService.shutdown();
+        futureCompletionService.shutdown();
+        IOUtils.close(transferNIOGroup);
+
+        if (previousOpenSearchPathConf != null) {
+            SocketAccess.doPrivileged(() -> System.setProperty("opensearch.path.conf", previousOpenSearchPathConf));
+        } else {
+            SocketAccess.doPrivileged(() -> System.clearProperty("opensearch.path.conf"));
+        }
         super.tearDown();
     }
 
@@ -113,7 +161,7 @@ protected Class<? extends Exception> unresponsiveExceptionType() {
     }
 
     @Override
-    protected BlobContainer createBlobContainer(
+    protected AsyncMultiStreamBlobContainer createBlobContainer(
         final @Nullable Integer maxRetries,
         final @Nullable TimeValue readTimeout,
         final @Nullable Boolean disableChunkedEncoding,
@@ -125,6 +173,7 @@ protected BlobContainer createBlobContainer(
         final InetSocketAddress address = httpServer.getAddress();
         final String endpoint = "http://" + InetAddresses.toUriString(address.getAddress()) + ":" + address.getPort();
         clientSettings.put(ENDPOINT_SETTING.getConcreteSettingForNamespace(clientName).getKey(), endpoint);
+        clientSettings.put(REGION.getConcreteSettingForNamespace(clientName).getKey(), "region");
 
         if (maxRetries != null) {
             clientSettings.put(MAX_RETRIES_SETTING.getConcreteSettingForNamespace(clientName).getKey(), maxRetries);
@@ -140,7 +189,8 @@ protected BlobContainer createBlobContainer(
         secureSettings.setString(S3ClientSettings.ACCESS_KEY_SETTING.getConcreteSettingForNamespace(clientName).getKey(), "access");
         secureSettings.setString(S3ClientSettings.SECRET_KEY_SETTING.getConcreteSettingForNamespace(clientName).getKey(), "secret");
         clientSettings.setSecureSettings(secureSettings);
-        service.refreshAndClearCache(S3ClientSettings.load(clientSettings.build()));
+        service.refreshAndClearCache(S3ClientSettings.load(clientSettings.build(), configPath()));
+        asyncService.refreshAndClearCache(S3ClientSettings.load(clientSettings.build(), configPath()));
 
         final RepositoryMetadata repositoryMetadata = new RepositoryMetadata(
             "repository",
@@ -148,16 +198,31 @@ protected BlobContainer createBlobContainer(
             Settings.builder().put(S3Repository.CLIENT_NAME.getKey(), clientName).build()
         );
 
+        AsyncExecutorContainer asyncExecutorContainer = new AsyncExecutorContainer(
+            futureCompletionService,
+            streamReaderService,
+            transferNIOGroup
+        );
+
         return new S3BlobContainer(
             BlobPath.cleanPath(),
             new S3BlobStore(
                 service,
+                asyncService,
+                true,
                 "bucket",
                 S3Repository.SERVER_SIDE_ENCRYPTION_SETTING.getDefault(Settings.EMPTY),
                 bufferSize == null ? S3Repository.BUFFER_SIZE_SETTING.getDefault(Settings.EMPTY) : bufferSize,
                 S3Repository.CANNED_ACL_SETTING.getDefault(Settings.EMPTY),
                 S3Repository.STORAGE_CLASS_SETTING.getDefault(Settings.EMPTY),
-                repositoryMetadata
+                repositoryMetadata,
+                new AsyncTransferManager(
+                    S3Repository.PARALLEL_MULTIPART_UPLOAD_MINIMUM_PART_SIZE_SETTING.getDefault(Settings.EMPTY).getBytes(),
+                    asyncExecutorContainer.getStreamReader(),
+                    asyncExecutorContainer.getStreamReader()
+                ),
+                asyncExecutorContainer,
+                asyncExecutorContainer
             )
         ) {
             @Override
@@ -211,12 +276,93 @@ public void testWriteBlobWithRetries() throws Exception {
         });
 
         final BlobContainer blobContainer = createBlobContainer(maxRetries, null, true, null);
-        try (InputStream stream = new InputStreamIndexInput(new ByteArrayIndexInput("desc", bytes), bytes.length)) {
+        try (InputStream stream = new ByteArrayInputStream(bytes)) {
             blobContainer.writeBlob("write_blob_max_retries", stream, bytes.length, false);
         }
         assertThat(countDown.isCountedDown(), is(true));
     }
 
+    public void testWriteBlobByStreamsWithRetries() throws Exception {
+        final int maxRetries = randomInt(5);
+        final CountDown countDown = new CountDown(maxRetries + 1);
+
+        final byte[] bytes = randomBlobContent();
+        httpServer.createContext("/bucket/write_blob_by_streams_max_retries", exchange -> {
+            if ("PUT".equals(exchange.getRequestMethod()) && exchange.getRequestURI().getQuery() == null) {
+                if (countDown.countDown()) {
+                    final BytesReference body = Streams.readFully(exchange.getRequestBody());
+                    if (Objects.deepEquals(bytes, BytesReference.toBytes(body))) {
+                        exchange.sendResponseHeaders(HttpStatus.SC_OK, -1);
+                    } else {
+                        exchange.sendResponseHeaders(HttpStatus.SC_BAD_REQUEST, -1);
+                    }
+                    exchange.close();
+                    return;
+                }
+
+                if (randomBoolean()) {
+                    if (randomBoolean()) {
+                        Streams.readFully(exchange.getRequestBody(), new byte[randomIntBetween(1, Math.max(1, bytes.length - 1))]);
+                    } else {
+                        Streams.readFully(exchange.getRequestBody());
+                        exchange.sendResponseHeaders(
+                            randomFrom(
+                                HttpStatus.SC_INTERNAL_SERVER_ERROR,
+                                HttpStatus.SC_BAD_GATEWAY,
+                                HttpStatus.SC_SERVICE_UNAVAILABLE,
+                                HttpStatus.SC_GATEWAY_TIMEOUT
+                            ),
+                            -1
+                        );
+                    }
+                }
+                exchange.close();
+            }
+        });
+
+        final AsyncMultiStreamBlobContainer blobContainer = createBlobContainer(maxRetries, null, true, null);
+        List<InputStream> openInputStreams = new ArrayList<>();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        ActionListener<Void> completionListener = ActionListener.wrap(resp -> { countDownLatch.countDown(); }, ex -> {
+            exceptionRef.set(ex);
+            countDownLatch.countDown();
+        });
+        blobContainer.asyncBlobUpload(new WriteContext("write_blob_by_streams_max_retries", new StreamContextSupplier() {
+            @Override
+            public StreamContext supplyStreamContext(long partSize) {
+                return new StreamContext(new CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException>() {
+                    @Override
+                    public InputStreamContainer apply(Integer partNo, Long size, Long position) throws IOException {
+                        InputStream inputStream = new OffsetRangeIndexInputStream(new ByteArrayIndexInput("desc", bytes), size, position);
+                        openInputStreams.add(inputStream);
+                        return new InputStreamContainer(inputStream, size, position);
+                    }
+                }, partSize, calculateLastPartSize(bytes.length, partSize), calculateNumberOfParts(bytes.length, partSize));
+            }
+        }, bytes.length, false, WritePriority.NORMAL, Assert::assertTrue, false, null), completionListener);
+
+        assertTrue(countDownLatch.await(5000, TimeUnit.SECONDS));
+
+        assertThat(countDown.isCountedDown(), is(true));
+
+        openInputStreams.forEach(inputStream -> {
+            try {
+                inputStream.close();
+            } catch (IOException e) {
+                fail("Failure while closing open input streams");
+            }
+        });
+    }
+
+    private long calculateLastPartSize(long totalSize, long partSize) {
+        return totalSize % partSize == 0 ? partSize : totalSize % partSize;
+    }
+
+    private int calculateNumberOfParts(long contentLength, long partSize) {
+        return (int) ((contentLength % partSize) == 0 ? contentLength / partSize : (contentLength / partSize) + 1);
+    }
+
     public void testWriteBlobWithReadTimeouts() {
         final byte[] bytes = randomByteArrayOfLength(randomIntBetween(10, 128));
         final TimeValue readTimeout = TimeValue.timeValueMillis(randomIntBetween(100, 500));
@@ -287,13 +433,13 @@ public void testWriteLargeBlob() throws Exception {
                 && exchange.getRequestURI().getQuery().contains("uploadId=TEST")
                 && exchange.getRequestURI().getQuery().contains("partNumber=")) {
                     // upload part request
-                    MD5DigestCalculatingInputStream md5 = new MD5DigestCalculatingInputStream(exchange.getRequestBody());
-                    BytesReference bytes = Streams.readFully(md5);
+                    SdkDigestInputStream digestInputStream = new SdkDigestInputStream(exchange.getRequestBody(), MessageDigests.md5());
+                    BytesReference bytes = Streams.readFully(digestInputStream);
                     assertThat((long) bytes.length(), anyOf(equalTo(lastPartSize), equalTo(bufferSize.getBytes())));
                     assertThat(contentLength, anyOf(equalTo(lastPartSize), equalTo(bufferSize.getBytes())));
 
                     if (countDownUploads.decrementAndGet() % 2 == 0) {
-                        exchange.getResponseHeaders().add("ETag", Base16.encodeAsString(md5.getMd5Digest()));
+                        exchange.getResponseHeaders().add("ETag", Base16.encodeAsString(digestInputStream.getMessageDigest().digest()));
                         exchange.sendResponseHeaders(HttpStatus.SC_OK, -1);
                         exchange.close();
                         return;
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobStoreContainerTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobStoreContainerTests.java
index 1c7dc05b89bf5..2e54705e9cd78 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobStoreContainerTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3BlobStoreContainerTests.java
@@ -32,45 +32,89 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.s3.model.AbortMultipartUploadRequest;
-import com.amazonaws.services.s3.model.CannedAccessControlList;
-import com.amazonaws.services.s3.model.CompleteMultipartUploadRequest;
-import com.amazonaws.services.s3.model.CompleteMultipartUploadResult;
-import com.amazonaws.services.s3.model.InitiateMultipartUploadRequest;
-import com.amazonaws.services.s3.model.InitiateMultipartUploadResult;
-import com.amazonaws.services.s3.model.ObjectMetadata;
-import com.amazonaws.services.s3.model.PartETag;
-import com.amazonaws.services.s3.model.PutObjectRequest;
-import com.amazonaws.services.s3.model.PutObjectResult;
-import com.amazonaws.services.s3.model.StorageClass;
-import com.amazonaws.services.s3.model.UploadPartRequest;
-import com.amazonaws.services.s3.model.UploadPartResult;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.core.async.AsyncResponseTransformer;
+import software.amazon.awssdk.core.exception.SdkException;
+import software.amazon.awssdk.core.sync.RequestBody;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.Checksum;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CompletedPart;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.DeleteObjectsRequest;
+import software.amazon.awssdk.services.s3.model.DeleteObjectsResponse;
+import software.amazon.awssdk.services.s3.model.GetObjectAttributesParts;
+import software.amazon.awssdk.services.s3.model.GetObjectAttributesRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectAttributesResponse;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.HeadObjectRequest;
+import software.amazon.awssdk.services.s3.model.HeadObjectResponse;
+import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
+import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
+import software.amazon.awssdk.services.s3.model.ObjectCannedACL;
+import software.amazon.awssdk.services.s3.model.ObjectIdentifier;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectResponse;
+import software.amazon.awssdk.services.s3.model.S3Error;
+import software.amazon.awssdk.services.s3.model.S3Object;
+import software.amazon.awssdk.services.s3.model.ServerSideEncryption;
+import software.amazon.awssdk.services.s3.model.StorageClass;
+import software.amazon.awssdk.services.s3.model.UploadPartRequest;
+import software.amazon.awssdk.services.s3.model.UploadPartResponse;
+import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;
+
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStoreException;
+import org.opensearch.common.blobstore.DeleteResult;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.ArgumentCaptor;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import org.mockito.ArgumentCaptor;
+import org.mockito.ArgumentMatchers;
+
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-import static org.mockito.Mockito.doAnswer;
 
 public class S3BlobStoreContainerTests extends OpenSearchTestCase {
 
@@ -100,6 +144,281 @@ public void testExecuteSingleUploadBlobSizeLargerThanBufferSize() {
         assertEquals("Upload request size [2097152] can't be larger than buffer size", e.getMessage());
     }
 
+    public void testBlobExists() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+
+        final S3Client client = mock(S3Client.class);
+        when(client.headObject(any(HeadObjectRequest.class))).thenReturn(HeadObjectResponse.builder().build());
+        final AmazonS3Reference clientReference = new AmazonS3Reference(client);
+        when(blobStore.clientReference()).thenReturn(clientReference);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        assertTrue(blobContainer.blobExists(blobName));
+        verify(client, times(1)).headObject(any(HeadObjectRequest.class));
+    }
+
+    public void testBlobExistsNoSuchKeyException() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+
+        final S3Client client = mock(S3Client.class);
+        when(client.headObject(any(HeadObjectRequest.class))).thenThrow(NoSuchKeyException.builder().build());
+        final AmazonS3Reference clientReference = new AmazonS3Reference(client);
+        when(blobStore.clientReference()).thenReturn(clientReference);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        assertFalse(blobContainer.blobExists(blobName));
+        verify(client, times(1)).headObject(any(HeadObjectRequest.class));
+    }
+
+    public void testBlobExistsRequestFailure() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+
+        final S3Client client = mock(S3Client.class);
+        final AmazonS3Reference clientReference = new AmazonS3Reference(client);
+        when(blobStore.clientReference()).thenReturn(clientReference);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        when(client.headObject(any(HeadObjectRequest.class))).thenThrow(new RuntimeException());
+
+        assertThrows(BlobStoreException.class, () -> blobContainer.blobExists(blobName));
+        verify(client, times(1)).headObject(any(HeadObjectRequest.class));
+    }
+
+    private static class MockListObjectsV2ResponseIterator implements Iterator<ListObjectsV2Response> {
+
+        private final int totalPageCount;
+        private final int s3ObjectsPerPage;
+        private final long s3ObjectSize;
+
+        private final AtomicInteger currInvocationCount = new AtomicInteger();
+        private final List<String> keysListed;
+        private final boolean throwExceptionOnNextInvocation;
+
+        public MockListObjectsV2ResponseIterator(int totalPageCount, int s3ObjectsPerPage, long s3ObjectSize) {
+            this(totalPageCount, s3ObjectsPerPage, s3ObjectSize, "");
+        }
+
+        public MockListObjectsV2ResponseIterator(int totalPageCount, int s3ObjectsPerPage, long s3ObjectSize, String blobPath) {
+            this(totalPageCount, s3ObjectsPerPage, s3ObjectSize, blobPath, false);
+        }
+
+        public MockListObjectsV2ResponseIterator(
+            int totalPageCount,
+            int s3ObjectsPerPage,
+            long s3ObjectSize,
+            String blobPath,
+            boolean throwExceptionOnNextInvocation
+        ) {
+            this.totalPageCount = totalPageCount;
+            this.s3ObjectsPerPage = s3ObjectsPerPage;
+            this.s3ObjectSize = s3ObjectSize;
+            this.throwExceptionOnNextInvocation = throwExceptionOnNextInvocation;
+            keysListed = new ArrayList<>();
+            for (int i = 0; i < totalPageCount * s3ObjectsPerPage; i++) {
+                keysListed.add(blobPath + UUID.randomUUID().toString());
+            }
+            // S3 lists keys in lexicographic order
+            keysListed.sort(String::compareTo);
+        }
+
+        @Override
+        public boolean hasNext() {
+            return currInvocationCount.get() < totalPageCount;
+        }
+
+        @Override
+        public ListObjectsV2Response next() {
+            if (throwExceptionOnNextInvocation) {
+                throw SdkException.builder().build();
+            }
+            if (currInvocationCount.getAndIncrement() < totalPageCount) {
+                List<S3Object> s3Objects = new ArrayList<>();
+                for (int i = 0; i < s3ObjectsPerPage; i++) {
+                    String s3ObjectKey = keysListed.get((currInvocationCount.get() - 1) * s3ObjectsPerPage + i);
+                    s3Objects.add(S3Object.builder().key(s3ObjectKey).size(s3ObjectSize).build());
+                }
+                return ListObjectsV2Response.builder().contents(s3Objects).build();
+            }
+            throw new NoSuchElementException();
+        }
+
+        public List<String> getKeysListed() {
+            return keysListed;
+        }
+
+        public int numberOfPagesFetched() {
+            return currInvocationCount.get();
+        }
+    }
+
+    public void testDelete() throws IOException {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        doAnswer(invocation -> new AmazonS3Reference(client)).when(blobStore).clientReference();
+
+        ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        final int totalPageCount = 3;
+        final long s3ObjectSize = ByteSizeUnit.MB.toBytes(5);
+        final int s3ObjectsPerPage = 5;
+        MockListObjectsV2ResponseIterator listObjectsV2ResponseIterator = new MockListObjectsV2ResponseIterator(
+            totalPageCount,
+            s3ObjectsPerPage,
+            s3ObjectSize
+        );
+        when(listObjectsV2Iterable.iterator()).thenReturn(listObjectsV2ResponseIterator);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        final List<String> keysDeleted = new ArrayList<>();
+        doAnswer(invocation -> {
+            DeleteObjectsRequest deleteObjectsRequest = invocation.getArgument(0);
+            keysDeleted.addAll(deleteObjectsRequest.delete().objects().stream().map(ObjectIdentifier::key).collect(Collectors.toList()));
+            return DeleteObjectsResponse.builder().build();
+        }).when(client).deleteObjects(any(DeleteObjectsRequest.class));
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        DeleteResult deleteResult = blobContainer.delete();
+        assertEquals(s3ObjectSize * s3ObjectsPerPage * totalPageCount, deleteResult.bytesDeleted());
+        assertEquals(s3ObjectsPerPage * totalPageCount, deleteResult.blobsDeleted());
+        // keysDeleted will have blobPath also
+        assertEquals(listObjectsV2ResponseIterator.getKeysListed().size(), keysDeleted.size() - 1);
+        assertTrue(keysDeleted.contains(blobPath.buildAsString()));
+        keysDeleted.remove(blobPath.buildAsString());
+        assertEquals(new HashSet<>(listObjectsV2ResponseIterator.getKeysListed()), new HashSet<>(keysDeleted));
+    }
+
+    public void testDeleteItemLevelErrorsDuringDelete() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        doAnswer(invocation -> new AmazonS3Reference(client)).when(blobStore).clientReference();
+
+        ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        final int totalPageCount = 3;
+        final long s3ObjectSize = ByteSizeUnit.MB.toBytes(5);
+        final int s3ObjectsPerPage = 5;
+        MockListObjectsV2ResponseIterator listObjectsV2ResponseIterator = new MockListObjectsV2ResponseIterator(
+            totalPageCount,
+            s3ObjectsPerPage,
+            s3ObjectSize
+        );
+        when(listObjectsV2Iterable.iterator()).thenReturn(listObjectsV2ResponseIterator);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        final List<String> keysFailedDeletion = new ArrayList<>();
+        doAnswer(invocation -> {
+            DeleteObjectsRequest deleteObjectsRequest = invocation.getArgument(0);
+            int i = 0;
+            for (ObjectIdentifier objectIdentifier : deleteObjectsRequest.delete().objects()) {
+                if (i % 2 == 0) {
+                    keysFailedDeletion.add(objectIdentifier.key());
+                }
+                i++;
+            }
+            return DeleteObjectsResponse.builder()
+                .errors(keysFailedDeletion.stream().map(key -> S3Error.builder().key(key).build()).collect(Collectors.toList()))
+                .build();
+        }).when(client).deleteObjects(any(DeleteObjectsRequest.class));
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        assertThrows(AssertionError.class, blobContainer::delete);
+    }
+
+    public void testDeleteSdkExceptionDuringListOperation() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        doAnswer(invocation -> new AmazonS3Reference(client)).when(blobStore).clientReference();
+
+        ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        final int totalPageCount = 3;
+        final long s3ObjectSize = ByteSizeUnit.MB.toBytes(5);
+        final int s3ObjectsPerPage = 5;
+        MockListObjectsV2ResponseIterator listObjectsV2ResponseIterator = new MockListObjectsV2ResponseIterator(
+            totalPageCount,
+            s3ObjectsPerPage,
+            s3ObjectSize
+        );
+        when(listObjectsV2Iterable.iterator()).thenReturn(listObjectsV2ResponseIterator);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        assertThrows(IOException.class, blobContainer::delete);
+    }
+
+    public void testDeleteSdkExceptionDuringDeleteOperation() {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+
+        final BlobPath blobPath = new BlobPath();
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        doAnswer(invocation -> new AmazonS3Reference(client)).when(blobStore).clientReference();
+
+        ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        final int totalPageCount = 3;
+        final long s3ObjectSize = ByteSizeUnit.MB.toBytes(5);
+        final int s3ObjectsPerPage = 5;
+        MockListObjectsV2ResponseIterator listObjectsV2ResponseIterator = new MockListObjectsV2ResponseIterator(
+            totalPageCount,
+            s3ObjectsPerPage,
+            s3ObjectSize
+        );
+        when(listObjectsV2Iterable.iterator()).thenReturn(listObjectsV2ResponseIterator);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        when(client.deleteObjects(any(DeleteObjectsRequest.class))).thenThrow(SdkException.builder().build());
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        assertThrows(IOException.class, blobContainer::delete);
+    }
+
     public void testExecuteSingleUpload() throws IOException {
         final String bucketName = randomAlphaOfLengthBetween(1, 10);
         final String blobName = randomAlphaOfLengthBetween(1, 10);
@@ -115,6 +434,7 @@ public void testExecuteSingleUpload() throws IOException {
         final S3BlobStore blobStore = mock(S3BlobStore.class);
         when(blobStore.bucket()).thenReturn(bucketName);
         when(blobStore.bufferSizeInBytes()).thenReturn((long) bufferSize);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
 
         final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
 
@@ -124,30 +444,37 @@ public void testExecuteSingleUpload() throws IOException {
         final StorageClass storageClass = randomFrom(StorageClass.values());
         when(blobStore.getStorageClass()).thenReturn(storageClass);
 
-        final CannedAccessControlList cannedAccessControlList = randomBoolean() ? randomFrom(CannedAccessControlList.values()) : null;
+        final ObjectCannedACL cannedAccessControlList = randomBoolean() ? randomFrom(ObjectCannedACL.values()) : null;
         if (cannedAccessControlList != null) {
             when(blobStore.getCannedACL()).thenReturn(cannedAccessControlList);
         }
 
-        final AmazonS3 client = mock(AmazonS3.class);
+        final S3Client client = mock(S3Client.class);
         final AmazonS3Reference clientReference = new AmazonS3Reference(client);
         when(blobStore.clientReference()).thenReturn(clientReference);
 
-        final ArgumentCaptor<PutObjectRequest> argumentCaptor = ArgumentCaptor.forClass(PutObjectRequest.class);
-        when(client.putObject(argumentCaptor.capture())).thenReturn(new PutObjectResult());
+        final ArgumentCaptor<PutObjectRequest> putObjectRequestArgumentCaptor = ArgumentCaptor.forClass(PutObjectRequest.class);
+        final ArgumentCaptor<RequestBody> requestBodyArgumentCaptor = ArgumentCaptor.forClass(RequestBody.class);
+        when(client.putObject(putObjectRequestArgumentCaptor.capture(), requestBodyArgumentCaptor.capture())).thenReturn(
+            PutObjectResponse.builder().build()
+        );
 
         final ByteArrayInputStream inputStream = new ByteArrayInputStream(new byte[blobSize]);
         blobContainer.executeSingleUpload(blobStore, blobName, inputStream, blobSize);
 
-        final PutObjectRequest request = argumentCaptor.getValue();
-        assertEquals(bucketName, request.getBucketName());
-        assertEquals(blobPath.buildAsString() + blobName, request.getKey());
-        assertEquals(inputStream, request.getInputStream());
-        assertEquals(blobSize, request.getMetadata().getContentLength());
-        assertEquals(storageClass.toString(), request.getStorageClass());
-        assertEquals(cannedAccessControlList, request.getCannedAcl());
+        final PutObjectRequest request = putObjectRequestArgumentCaptor.getValue();
+        final RequestBody requestBody = requestBodyArgumentCaptor.getValue();
+        assertEquals(bucketName, request.bucket());
+        assertEquals(blobPath.buildAsString() + blobName, request.key());
+        byte[] expectedBytes = inputStream.readAllBytes();
+        try (InputStream is = requestBody.contentStreamProvider().newStream()) {
+            assertArrayEquals(expectedBytes, is.readAllBytes());
+        }
+        assertEquals(blobSize, request.contentLength().longValue());
+        assertEquals(storageClass, request.storageClass());
+        assertEquals(cannedAccessControlList, request.acl());
         if (serverSideEncryption) {
-            assertEquals(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION, request.getMetadata().getSSEAlgorithm());
+            assertEquals(ServerSideEncryption.AES256, request.serverSideEncryption());
         }
     }
 
@@ -189,6 +516,7 @@ public void testExecuteMultipartUpload() throws IOException {
 
         final S3BlobStore blobStore = mock(S3BlobStore.class);
         when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
         when(blobStore.bufferSizeInBytes()).thenReturn(bufferSize);
 
         final boolean serverSideEncryption = randomBoolean();
@@ -197,21 +525,25 @@ public void testExecuteMultipartUpload() throws IOException {
         final StorageClass storageClass = randomFrom(StorageClass.values());
         when(blobStore.getStorageClass()).thenReturn(storageClass);
 
-        final CannedAccessControlList cannedAccessControlList = randomBoolean() ? randomFrom(CannedAccessControlList.values()) : null;
+        final ObjectCannedACL cannedAccessControlList = randomBoolean() ? randomFrom(ObjectCannedACL.values()) : null;
         if (cannedAccessControlList != null) {
             when(blobStore.getCannedACL()).thenReturn(cannedAccessControlList);
         }
 
-        final AmazonS3 client = mock(AmazonS3.class);
+        final S3Client client = mock(S3Client.class);
         final AmazonS3Reference clientReference = new AmazonS3Reference(client);
         when(blobStore.clientReference()).thenReturn(clientReference);
 
-        final ArgumentCaptor<InitiateMultipartUploadRequest> initArgCaptor = ArgumentCaptor.forClass(InitiateMultipartUploadRequest.class);
-        final InitiateMultipartUploadResult initResult = new InitiateMultipartUploadResult();
-        initResult.setUploadId(randomAlphaOfLength(10));
-        when(client.initiateMultipartUpload(initArgCaptor.capture())).thenReturn(initResult);
+        final ArgumentCaptor<CreateMultipartUploadRequest> createMultipartUploadRequestArgumentCaptor = ArgumentCaptor.forClass(
+            CreateMultipartUploadRequest.class
+        );
+        final CreateMultipartUploadResponse createMultipartUploadResponse = CreateMultipartUploadResponse.builder()
+            .uploadId(randomAlphaOfLength(10))
+            .build();
+        when(client.createMultipartUpload(createMultipartUploadRequestArgumentCaptor.capture())).thenReturn(createMultipartUploadResponse);
 
-        final ArgumentCaptor<UploadPartRequest> uploadArgCaptor = ArgumentCaptor.forClass(UploadPartRequest.class);
+        final ArgumentCaptor<UploadPartRequest> uploadPartRequestArgumentCaptor = ArgumentCaptor.forClass(UploadPartRequest.class);
+        final ArgumentCaptor<RequestBody> requestBodyArgumentCaptor = ArgumentCaptor.forClass(RequestBody.class);
 
         final List<String> expectedEtags = new ArrayList<>();
         final long partSize = Math.min(bufferSize, blobSize);
@@ -221,59 +553,65 @@ public void testExecuteMultipartUpload() throws IOException {
             totalBytes += partSize;
         } while (totalBytes < blobSize);
 
-        when(client.uploadPart(uploadArgCaptor.capture())).thenAnswer(invocationOnMock -> {
-            final UploadPartRequest request = (UploadPartRequest) invocationOnMock.getArguments()[0];
-            final UploadPartResult response = new UploadPartResult();
-            response.setPartNumber(request.getPartNumber());
-            response.setETag(expectedEtags.get(request.getPartNumber() - 1));
-            return response;
-        });
+        when(client.uploadPart(uploadPartRequestArgumentCaptor.capture(), requestBodyArgumentCaptor.capture())).thenAnswer(
+            invocationOnMock -> {
+                final UploadPartRequest request = (UploadPartRequest) invocationOnMock.getArguments()[0];
+                final UploadPartResponse response = UploadPartResponse.builder().eTag(expectedEtags.get(request.partNumber() - 1)).build();
+                return response;
+            }
+        );
 
-        final ArgumentCaptor<CompleteMultipartUploadRequest> compArgCaptor = ArgumentCaptor.forClass(CompleteMultipartUploadRequest.class);
-        when(client.completeMultipartUpload(compArgCaptor.capture())).thenReturn(new CompleteMultipartUploadResult());
+        final ArgumentCaptor<CompleteMultipartUploadRequest> completeMultipartUploadRequestArgumentCaptor = ArgumentCaptor.forClass(
+            CompleteMultipartUploadRequest.class
+        );
+        when(client.completeMultipartUpload(completeMultipartUploadRequestArgumentCaptor.capture())).thenReturn(
+            CompleteMultipartUploadResponse.builder().build()
+        );
 
         final ByteArrayInputStream inputStream = new ByteArrayInputStream(new byte[0]);
         final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
         blobContainer.executeMultipartUpload(blobStore, blobName, inputStream, blobSize);
 
-        final InitiateMultipartUploadRequest initRequest = initArgCaptor.getValue();
-        assertEquals(bucketName, initRequest.getBucketName());
-        assertEquals(blobPath.buildAsString() + blobName, initRequest.getKey());
-        assertEquals(storageClass, initRequest.getStorageClass());
-        assertEquals(cannedAccessControlList, initRequest.getCannedACL());
+        final CreateMultipartUploadRequest initRequest = createMultipartUploadRequestArgumentCaptor.getValue();
+        assertEquals(bucketName, initRequest.bucket());
+        assertEquals(blobPath.buildAsString() + blobName, initRequest.key());
+        assertEquals(storageClass, initRequest.storageClass());
+        assertEquals(cannedAccessControlList, initRequest.acl());
         if (serverSideEncryption) {
-            assertEquals(ObjectMetadata.AES_256_SERVER_SIDE_ENCRYPTION, initRequest.getObjectMetadata().getSSEAlgorithm());
+            assertEquals(ServerSideEncryption.AES256, initRequest.serverSideEncryption());
         }
 
         final Tuple<Long, Long> numberOfParts = S3BlobContainer.numberOfMultiparts(blobSize, bufferSize);
 
-        final List<UploadPartRequest> uploadRequests = uploadArgCaptor.getAllValues();
+        final List<UploadPartRequest> uploadRequests = uploadPartRequestArgumentCaptor.getAllValues();
+        final List<RequestBody> requestBodies = requestBodyArgumentCaptor.getAllValues();
         assertEquals(numberOfParts.v1().intValue(), uploadRequests.size());
 
         for (int i = 0; i < uploadRequests.size(); i++) {
-            final UploadPartRequest uploadRequest = uploadRequests.get(i);
-
-            assertEquals(bucketName, uploadRequest.getBucketName());
-            assertEquals(blobPath.buildAsString() + blobName, uploadRequest.getKey());
-            assertEquals(initResult.getUploadId(), uploadRequest.getUploadId());
-            assertEquals(i + 1, uploadRequest.getPartNumber());
-            assertEquals(inputStream, uploadRequest.getInputStream());
-
-            if (i == (uploadRequests.size() - 1)) {
-                assertTrue(uploadRequest.isLastPart());
-                assertEquals(numberOfParts.v2().longValue(), uploadRequest.getPartSize());
-            } else {
-                assertFalse(uploadRequest.isLastPart());
-                assertEquals(bufferSize, uploadRequest.getPartSize());
+            final UploadPartRequest uploadPartRequest = uploadRequests.get(i);
+            final RequestBody requestBody = requestBodies.get(i);
+
+            assertEquals(bucketName, uploadPartRequest.bucket());
+            assertEquals(blobPath.buildAsString() + blobName, uploadPartRequest.key());
+            assertEquals(createMultipartUploadResponse.uploadId(), uploadPartRequest.uploadId());
+            assertEquals(i + 1, uploadPartRequest.partNumber().intValue());
+            byte[] expectedBytes = inputStream.readAllBytes();
+            try (InputStream is = requestBody.contentStreamProvider().newStream()) {
+                byte[] actualBytes = is.readAllBytes();
+                assertArrayEquals(expectedBytes, actualBytes);
             }
         }
 
-        final CompleteMultipartUploadRequest compRequest = compArgCaptor.getValue();
-        assertEquals(bucketName, compRequest.getBucketName());
-        assertEquals(blobPath.buildAsString() + blobName, compRequest.getKey());
-        assertEquals(initResult.getUploadId(), compRequest.getUploadId());
+        final CompleteMultipartUploadRequest completeMultipartUploadRequest = completeMultipartUploadRequestArgumentCaptor.getValue();
+        assertEquals(bucketName, completeMultipartUploadRequest.bucket());
+        assertEquals(blobPath.buildAsString() + blobName, completeMultipartUploadRequest.key());
+        assertEquals(createMultipartUploadResponse.uploadId(), completeMultipartUploadRequest.uploadId());
 
-        final List<String> actualETags = compRequest.getPartETags().stream().map(PartETag::getETag).collect(Collectors.toList());
+        final List<String> actualETags = completeMultipartUploadRequest.multipartUpload()
+            .parts()
+            .stream()
+            .map(CompletedPart::eTag)
+            .collect(Collectors.toList());
         assertEquals(expectedEtags, actualETags);
     }
 
@@ -289,8 +627,9 @@ public void testExecuteMultipartUploadAborted() {
         when(blobStore.bucket()).thenReturn(bucketName);
         when(blobStore.bufferSizeInBytes()).thenReturn(bufferSize);
         when(blobStore.getStorageClass()).thenReturn(randomFrom(StorageClass.values()));
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
 
-        final AmazonS3 client = mock(AmazonS3.class);
+        final S3Client client = mock(S3Client.class);
         final AmazonS3Reference clientReference = new AmazonS3Reference(client);
         doAnswer(invocation -> {
             clientReference.incRef();
@@ -300,34 +639,34 @@ public void testExecuteMultipartUploadAborted() {
         final String uploadId = randomAlphaOfLength(25);
 
         final int stage = randomInt(2);
-        final List<AmazonClientException> exceptions = Arrays.asList(
-            new AmazonClientException("Expected initialization request to fail"),
-            new AmazonClientException("Expected upload part request to fail"),
-            new AmazonClientException("Expected completion request to fail")
+        final List<SdkException> exceptions = Arrays.asList(
+            SdkException.create("Expected initialization request to fail", new RuntimeException()),
+            SdkException.create("Expected upload part request to fail", new RuntimeException()),
+            SdkException.create("Expected completion request to fail", new RuntimeException())
         );
 
         if (stage == 0) {
             // Fail the initialization request
-            when(client.initiateMultipartUpload(any(InitiateMultipartUploadRequest.class))).thenThrow(exceptions.get(stage));
+            when(client.createMultipartUpload(any(CreateMultipartUploadRequest.class))).thenThrow(exceptions.get(stage));
 
         } else if (stage == 1) {
-            final InitiateMultipartUploadResult initResult = new InitiateMultipartUploadResult();
-            initResult.setUploadId(uploadId);
-            when(client.initiateMultipartUpload(any(InitiateMultipartUploadRequest.class))).thenReturn(initResult);
+            final CreateMultipartUploadResponse createMultipartUploadResponse = CreateMultipartUploadResponse.builder()
+                .uploadId(uploadId)
+                .build();
+            when(client.createMultipartUpload(any(CreateMultipartUploadRequest.class))).thenReturn(createMultipartUploadResponse);
 
             // Fail the upload part request
-            when(client.uploadPart(any(UploadPartRequest.class))).thenThrow(exceptions.get(stage));
+            when(client.uploadPart(any(UploadPartRequest.class), any(RequestBody.class))).thenThrow(exceptions.get(stage));
 
         } else {
-            final InitiateMultipartUploadResult initResult = new InitiateMultipartUploadResult();
-            initResult.setUploadId(uploadId);
-            when(client.initiateMultipartUpload(any(InitiateMultipartUploadRequest.class))).thenReturn(initResult);
+            final CreateMultipartUploadResponse createMultipartUploadResponse = CreateMultipartUploadResponse.builder()
+                .uploadId(uploadId)
+                .build();
+            when(client.createMultipartUpload(any(CreateMultipartUploadRequest.class))).thenReturn(createMultipartUploadResponse);
 
-            when(client.uploadPart(any(UploadPartRequest.class))).thenAnswer(invocationOnMock -> {
+            when(client.uploadPart(any(UploadPartRequest.class), any(RequestBody.class))).thenAnswer(invocationOnMock -> {
                 final UploadPartRequest request = (UploadPartRequest) invocationOnMock.getArguments()[0];
-                final UploadPartResult response = new UploadPartResult();
-                response.setPartNumber(request.getPartNumber());
-                response.setETag(randomAlphaOfLength(20));
+                final UploadPartResponse response = UploadPartResponse.builder().eTag(randomAlphaOfLength(20)).build();
                 return response;
             });
 
@@ -336,7 +675,7 @@ public void testExecuteMultipartUploadAborted() {
         }
 
         final ArgumentCaptor<AbortMultipartUploadRequest> argumentCaptor = ArgumentCaptor.forClass(AbortMultipartUploadRequest.class);
-        doNothing().when(client).abortMultipartUpload(argumentCaptor.capture());
+        when(client.abortMultipartUpload(argumentCaptor.capture())).thenReturn(AbortMultipartUploadResponse.builder().build());
 
         final IOException e = expectThrows(IOException.class, () -> {
             final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
@@ -344,32 +683,32 @@ public void testExecuteMultipartUploadAborted() {
         });
 
         assertEquals("Unable to upload object [" + blobName + "] using multipart upload", e.getMessage());
-        assertThat(e.getCause(), instanceOf(AmazonClientException.class));
+        assertThat(e.getCause(), instanceOf(SdkException.class));
         assertEquals(exceptions.get(stage).getMessage(), e.getCause().getMessage());
 
         if (stage == 0) {
-            verify(client, times(1)).initiateMultipartUpload(any(InitiateMultipartUploadRequest.class));
-            verify(client, times(0)).uploadPart(any(UploadPartRequest.class));
+            verify(client, times(1)).createMultipartUpload(any(CreateMultipartUploadRequest.class));
+            verify(client, times(0)).uploadPart(any(UploadPartRequest.class), any(RequestBody.class));
             verify(client, times(0)).completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
             verify(client, times(0)).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
 
         } else {
-            verify(client, times(1)).initiateMultipartUpload(any(InitiateMultipartUploadRequest.class));
+            verify(client, times(1)).createMultipartUpload(any(CreateMultipartUploadRequest.class));
 
             if (stage == 1) {
-                verify(client, times(1)).uploadPart(any(UploadPartRequest.class));
+                verify(client, times(1)).uploadPart(any(UploadPartRequest.class), any(RequestBody.class));
                 verify(client, times(0)).completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
             } else {
-                verify(client, times(6)).uploadPart(any(UploadPartRequest.class));
+                verify(client, times(6)).uploadPart(any(UploadPartRequest.class), any(RequestBody.class));
                 verify(client, times(1)).completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
             }
 
             verify(client, times(1)).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
 
             final AbortMultipartUploadRequest abortRequest = argumentCaptor.getValue();
-            assertEquals(bucketName, abortRequest.getBucketName());
-            assertEquals(blobName, abortRequest.getKey());
-            assertEquals(uploadId, abortRequest.getUploadId());
+            assertEquals(bucketName, abortRequest.bucket());
+            assertEquals(blobName, abortRequest.key());
+            assertEquals(uploadId, abortRequest.uploadId());
         }
     }
 
@@ -407,23 +746,22 @@ public void testInitCannedACL() {
             "public-read",
             "public-read-write",
             "authenticated-read",
-            "log-delivery-write",
             "bucket-owner-read",
             "bucket-owner-full-control" };
 
         // empty acl
-        assertThat(S3BlobStore.initCannedACL(null), equalTo(CannedAccessControlList.Private));
-        assertThat(S3BlobStore.initCannedACL(""), equalTo(CannedAccessControlList.Private));
+        assertThat(S3BlobStore.initCannedACL(null), equalTo(ObjectCannedACL.PRIVATE));
+        assertThat(S3BlobStore.initCannedACL(""), equalTo(ObjectCannedACL.PRIVATE));
 
         // it should init cannedACL correctly
         for (String aclString : aclList) {
-            CannedAccessControlList acl = S3BlobStore.initCannedACL(aclString);
+            ObjectCannedACL acl = S3BlobStore.initCannedACL(aclString);
             assertThat(acl.toString(), equalTo(aclString));
         }
 
         // it should accept all aws cannedACLs
-        for (CannedAccessControlList awsList : CannedAccessControlList.values()) {
-            CannedAccessControlList acl = S3BlobStore.initCannedACL(awsList.toString());
+        for (ObjectCannedACL awsList : ObjectCannedACL.values()) {
+            ObjectCannedACL acl = S3BlobStore.initCannedACL(awsList.toString());
             assertThat(acl, equalTo(awsList));
         }
     }
@@ -435,23 +773,23 @@ public void testInvalidCannedACL() {
 
     public void testInitStorageClass() {
         // it should default to `standard`
-        assertThat(S3BlobStore.initStorageClass(null), equalTo(StorageClass.Standard));
-        assertThat(S3BlobStore.initStorageClass(""), equalTo(StorageClass.Standard));
+        assertThat(S3BlobStore.initStorageClass(null), equalTo(StorageClass.STANDARD));
+        assertThat(S3BlobStore.initStorageClass(""), equalTo(StorageClass.STANDARD));
 
         // it should accept [standard, standard_ia, onezone_ia, reduced_redundancy, intelligent_tiering]
-        assertThat(S3BlobStore.initStorageClass("standard"), equalTo(StorageClass.Standard));
-        assertThat(S3BlobStore.initStorageClass("standard_ia"), equalTo(StorageClass.StandardInfrequentAccess));
-        assertThat(S3BlobStore.initStorageClass("onezone_ia"), equalTo(StorageClass.OneZoneInfrequentAccess));
-        assertThat(S3BlobStore.initStorageClass("reduced_redundancy"), equalTo(StorageClass.ReducedRedundancy));
-        assertThat(S3BlobStore.initStorageClass("intelligent_tiering"), equalTo(StorageClass.IntelligentTiering));
+        assertThat(S3BlobStore.initStorageClass("standard"), equalTo(StorageClass.STANDARD));
+        assertThat(S3BlobStore.initStorageClass("standard_ia"), equalTo(StorageClass.STANDARD_IA));
+        assertThat(S3BlobStore.initStorageClass("onezone_ia"), equalTo(StorageClass.ONEZONE_IA));
+        assertThat(S3BlobStore.initStorageClass("reduced_redundancy"), equalTo(StorageClass.REDUCED_REDUNDANCY));
+        assertThat(S3BlobStore.initStorageClass("intelligent_tiering"), equalTo(StorageClass.INTELLIGENT_TIERING));
     }
 
     public void testCaseInsensitiveStorageClass() {
-        assertThat(S3BlobStore.initStorageClass("sTandaRd"), equalTo(StorageClass.Standard));
-        assertThat(S3BlobStore.initStorageClass("sTandaRd_Ia"), equalTo(StorageClass.StandardInfrequentAccess));
-        assertThat(S3BlobStore.initStorageClass("oNeZoNe_iA"), equalTo(StorageClass.OneZoneInfrequentAccess));
-        assertThat(S3BlobStore.initStorageClass("reduCED_redundancy"), equalTo(StorageClass.ReducedRedundancy));
-        assertThat(S3BlobStore.initStorageClass("intelLigeNt_tieriNG"), equalTo(StorageClass.IntelligentTiering));
+        assertThat(S3BlobStore.initStorageClass("sTandaRd"), equalTo(StorageClass.STANDARD));
+        assertThat(S3BlobStore.initStorageClass("sTandaRd_Ia"), equalTo(StorageClass.STANDARD_IA));
+        assertThat(S3BlobStore.initStorageClass("oNeZoNe_iA"), equalTo(StorageClass.ONEZONE_IA));
+        assertThat(S3BlobStore.initStorageClass("reduCED_redundancy"), equalTo(StorageClass.REDUCED_REDUNDANCY));
+        assertThat(S3BlobStore.initStorageClass("intelLigeNt_tieriNG"), equalTo(StorageClass.INTELLIGENT_TIERING));
     }
 
     public void testInvalidStorageClass() {
@@ -470,4 +808,481 @@ private static void assertNumberOfMultiparts(final int expectedParts, final long
         assertEquals("Expected number of parts [" + expectedParts + "] but got [" + result.v1() + "]", expectedParts, (long) result.v1());
         assertEquals("Expected remaining [" + expectedRemaining + "] but got [" + result.v2() + "]", expectedRemaining, (long) result.v2());
     }
+
+    public void testListBlobsByPrefix() throws IOException {
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        final AmazonS3Reference clientReference = new AmazonS3Reference(client);
+        when(blobStore.clientReference()).thenReturn(clientReference);
+
+        BlobPath blobPath = mock(BlobPath.class);
+        when(blobPath.buildAsString()).thenReturn("/dummy/path");
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        final ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        MockListObjectsV2ResponseIterator iterator = new MockListObjectsV2ResponseIterator(2, 5, 100);
+        when(listObjectsV2Iterable.iterator()).thenReturn(iterator);
+
+        Map<String, BlobMetadata> listOfBlobs = blobContainer.listBlobsByPrefix(null);
+        assertEquals(10, listOfBlobs.size());
+
+        Set<String> keys = iterator.keysListed.stream()
+            .map(s -> s.substring(blobPath.buildAsString().length()))
+            .collect(Collectors.toSet());
+        assertEquals(keys, listOfBlobs.keySet());
+    }
+
+    private void testListBlobsByPrefixInLexicographicOrder(
+        int limit,
+        int expectedNumberofPagesFetched,
+        BlobContainer.BlobNameSortOrder blobNameSortOrder
+    ) throws IOException {
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+
+        final S3Client client = mock(S3Client.class);
+        final AmazonS3Reference clientReference = new AmazonS3Reference(client);
+        when(blobStore.clientReference()).thenReturn(clientReference);
+
+        BlobPath blobPath = mock(BlobPath.class);
+        when(blobPath.buildAsString()).thenReturn("/dummy/path");
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        final ListObjectsV2Iterable listObjectsV2Iterable = mock(ListObjectsV2Iterable.class);
+        when(client.listObjectsV2Paginator(any(ListObjectsV2Request.class))).thenReturn(listObjectsV2Iterable);
+
+        final MockListObjectsV2ResponseIterator iterator = new MockListObjectsV2ResponseIterator(2, 5, 100, blobPath.buildAsString());
+        when(listObjectsV2Iterable.iterator()).thenReturn(iterator);
+
+        if (limit >= 0) {
+            blobContainer.listBlobsByPrefixInSortedOrder(null, limit, blobNameSortOrder, new ActionListener<>() {
+                @Override
+                public void onResponse(List<BlobMetadata> blobMetadata) {
+                    int actualLimit = Math.max(0, Math.min(limit, 10));
+                    assertEquals(actualLimit, blobMetadata.size());
+
+                    List<String> keys = iterator.keysListed.stream()
+                        .map(s -> s.substring(blobPath.buildAsString().length()))
+                        .collect(Collectors.toList());
+                    Comparator<String> keysComparator = String::compareTo;
+                    if (blobNameSortOrder != BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC) {
+                        keysComparator = Collections.reverseOrder(String::compareTo);
+                    }
+                    keys.sort(keysComparator);
+                    List<String> sortedKeys = keys.subList(0, actualLimit);
+                    assertEquals(sortedKeys, blobMetadata.stream().map(BlobMetadata::name).collect(Collectors.toList()));
+                    assertEquals(expectedNumberofPagesFetched, iterator.numberOfPagesFetched());
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    fail("blobContainer.listBlobsByPrefixInLexicographicOrder failed with exception: " + e.getMessage());
+                }
+            });
+        } else {
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> blobContainer.listBlobsByPrefixInSortedOrder(null, limit, blobNameSortOrder, new ActionListener<>() {
+                    @Override
+                    public void onResponse(List<BlobMetadata> blobMetadata) {}
+
+                    @Override
+                    public void onFailure(Exception e) {}
+                })
+            );
+        }
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithNegativeLimit() throws IOException {
+        testListBlobsByPrefixInLexicographicOrder(-5, 0, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithZeroLimit() throws IOException {
+        testListBlobsByPrefixInLexicographicOrder(0, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitLessThanPageSize() throws IOException {
+        testListBlobsByPrefixInLexicographicOrder(2, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitGreaterThanPageSize() throws IOException {
+        testListBlobsByPrefixInLexicographicOrder(8, 2, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitGreaterThanNumberOfRecords() throws IOException {
+        testListBlobsByPrefixInLexicographicOrder(12, 2, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testReadBlobAsyncMultiPart() throws Exception {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+        final String checksum = randomAlphaOfLength(10);
+
+        final long objectSize = 100L;
+        final int objectPartCount = 10;
+        final int partSize = 10;
+
+        final S3AsyncClient s3AsyncClient = mock(S3AsyncClient.class);
+        final AmazonAsyncS3Reference amazonAsyncS3Reference = new AmazonAsyncS3Reference(
+            AmazonAsyncS3WithCredentials.create(s3AsyncClient, s3AsyncClient, null)
+        );
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        final BlobPath blobPath = new BlobPath();
+
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+        when(blobStore.serverSideEncryption()).thenReturn(false);
+        when(blobStore.asyncClientReference()).thenReturn(amazonAsyncS3Reference);
+
+        CompletableFuture<GetObjectAttributesResponse> getObjectAttributesResponseCompletableFuture = new CompletableFuture<>();
+        getObjectAttributesResponseCompletableFuture.complete(
+            GetObjectAttributesResponse.builder()
+                .checksum(Checksum.builder().checksumCRC32(checksum).build())
+                .objectSize(objectSize)
+                .objectParts(GetObjectAttributesParts.builder().totalPartsCount(objectPartCount).build())
+                .build()
+        );
+        when(s3AsyncClient.getObjectAttributes(any(GetObjectAttributesRequest.class))).thenReturn(
+            getObjectAttributesResponseCompletableFuture
+        );
+
+        mockObjectPartResponse(s3AsyncClient, bucketName, blobName, objectPartCount, partSize, objectSize);
+
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        CountingCompletionListener<ReadContext> readContextActionListener = new CountingCompletionListener<>();
+        LatchedActionListener<ReadContext> listener = new LatchedActionListener<>(readContextActionListener, countDownLatch);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+        blobContainer.readBlobAsync(blobName, listener);
+        countDownLatch.await();
+
+        assertEquals(1, readContextActionListener.getResponseCount());
+        assertEquals(0, readContextActionListener.getFailureCount());
+        ReadContext readContext = readContextActionListener.getResponse();
+        assertEquals(objectPartCount, readContext.getNumberOfParts());
+        assertEquals(checksum, readContext.getBlobChecksum());
+        assertEquals(objectSize, readContext.getBlobSize());
+
+        for (int partNumber = 1; partNumber < objectPartCount; partNumber++) {
+            InputStreamContainer inputStreamContainer = readContext.getPartStreams().get(partNumber).get().join();
+            final int offset = partNumber * partSize;
+            assertEquals(partSize, inputStreamContainer.getContentLength());
+            assertEquals(offset, inputStreamContainer.getOffset());
+            assertEquals(partSize, inputStreamContainer.getInputStream().readAllBytes().length);
+        }
+    }
+
+    public void testReadBlobAsyncSinglePart() throws Exception {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+        final String checksum = randomAlphaOfLength(10);
+
+        final int objectSize = 100;
+
+        final S3AsyncClient s3AsyncClient = mock(S3AsyncClient.class);
+        final AmazonAsyncS3Reference amazonAsyncS3Reference = new AmazonAsyncS3Reference(
+            AmazonAsyncS3WithCredentials.create(s3AsyncClient, s3AsyncClient, null)
+        );
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        final BlobPath blobPath = new BlobPath();
+
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+        when(blobStore.serverSideEncryption()).thenReturn(false);
+        when(blobStore.asyncClientReference()).thenReturn(amazonAsyncS3Reference);
+
+        CompletableFuture<GetObjectAttributesResponse> getObjectAttributesResponseCompletableFuture = new CompletableFuture<>();
+        getObjectAttributesResponseCompletableFuture.complete(
+            GetObjectAttributesResponse.builder()
+                .checksum(Checksum.builder().checksumCRC32(checksum).build())
+                .objectSize((long) objectSize)
+                .build()
+        );
+        when(s3AsyncClient.getObjectAttributes(any(GetObjectAttributesRequest.class))).thenReturn(
+            getObjectAttributesResponseCompletableFuture
+        );
+
+        mockObjectResponse(s3AsyncClient, bucketName, blobName, objectSize);
+
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        CountingCompletionListener<ReadContext> readContextActionListener = new CountingCompletionListener<>();
+        LatchedActionListener<ReadContext> listener = new LatchedActionListener<>(readContextActionListener, countDownLatch);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+        blobContainer.readBlobAsync(blobName, listener);
+        countDownLatch.await();
+
+        assertEquals(1, readContextActionListener.getResponseCount());
+        assertEquals(0, readContextActionListener.getFailureCount());
+        ReadContext readContext = readContextActionListener.getResponse();
+        assertEquals(1, readContext.getNumberOfParts());
+        assertEquals(checksum, readContext.getBlobChecksum());
+        assertEquals(objectSize, readContext.getBlobSize());
+
+        InputStreamContainer inputStreamContainer = readContext.getPartStreams().stream().findFirst().get().get().join();
+        assertEquals(objectSize, inputStreamContainer.getContentLength());
+        assertEquals(0, inputStreamContainer.getOffset());
+        assertEquals(objectSize, inputStreamContainer.getInputStream().readAllBytes().length);
+
+    }
+
+    public void testReadBlobAsyncFailure() throws Exception {
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+        final String checksum = randomAlphaOfLength(10);
+
+        final long objectSize = 100L;
+        final int objectPartCount = 10;
+
+        final S3AsyncClient s3AsyncClient = mock(S3AsyncClient.class);
+        final AmazonAsyncS3Reference amazonAsyncS3Reference = new AmazonAsyncS3Reference(
+            AmazonAsyncS3WithCredentials.create(s3AsyncClient, s3AsyncClient, null)
+        );
+
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        final BlobPath blobPath = new BlobPath();
+
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+        when(blobStore.serverSideEncryption()).thenReturn(false);
+        when(blobStore.asyncClientReference()).thenReturn(amazonAsyncS3Reference);
+
+        CompletableFuture<GetObjectAttributesResponse> getObjectAttributesResponseCompletableFuture = new CompletableFuture<>();
+        getObjectAttributesResponseCompletableFuture.complete(
+            GetObjectAttributesResponse.builder()
+                .checksum(Checksum.builder().checksumCRC32(checksum).build())
+                .objectSize(objectSize)
+                .objectParts(GetObjectAttributesParts.builder().totalPartsCount(objectPartCount).build())
+                .build()
+        );
+        when(s3AsyncClient.getObjectAttributes(any(GetObjectAttributesRequest.class))).thenThrow(new RuntimeException());
+
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        CountingCompletionListener<ReadContext> readContextActionListener = new CountingCompletionListener<>();
+        LatchedActionListener<ReadContext> listener = new LatchedActionListener<>(readContextActionListener, countDownLatch);
+
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+        blobContainer.readBlobAsync(blobName, listener);
+        countDownLatch.await();
+
+        assertEquals(0, readContextActionListener.getResponseCount());
+        assertEquals(1, readContextActionListener.getFailureCount());
+    }
+
+    public void testGetBlobMetadata() throws Exception {
+        final String checksum = randomAlphaOfLengthBetween(1, 10);
+        final long objectSize = 100L;
+        final int objectPartCount = 10;
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+
+        final S3AsyncClient s3AsyncClient = mock(S3AsyncClient.class);
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        final BlobPath blobPath = new BlobPath();
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+        when(blobStore.serverSideEncryption()).thenReturn(false);
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        CompletableFuture<GetObjectAttributesResponse> getObjectAttributesResponseCompletableFuture = new CompletableFuture<>();
+        getObjectAttributesResponseCompletableFuture.complete(
+            GetObjectAttributesResponse.builder()
+                .checksum(Checksum.builder().checksumCRC32(checksum).build())
+                .objectSize(objectSize)
+                .objectParts(GetObjectAttributesParts.builder().totalPartsCount(objectPartCount).build())
+                .build()
+        );
+        when(s3AsyncClient.getObjectAttributes(any(GetObjectAttributesRequest.class))).thenReturn(
+            getObjectAttributesResponseCompletableFuture
+        );
+
+        CompletableFuture<GetObjectAttributesResponse> responseFuture = blobContainer.getBlobMetadata(s3AsyncClient, bucketName, blobName);
+        GetObjectAttributesResponse objectAttributesResponse = responseFuture.get();
+
+        assertEquals(checksum, objectAttributesResponse.checksum().checksumCRC32());
+        assertEquals(Long.valueOf(objectSize), objectAttributesResponse.objectSize());
+        assertEquals(Integer.valueOf(objectPartCount), objectAttributesResponse.objectParts().totalPartsCount());
+    }
+
+    public void testGetBlobPartInputStream() throws Exception {
+        final String blobName = randomAlphaOfLengthBetween(1, 10);
+        final String bucketName = randomAlphaOfLengthBetween(1, 10);
+        final long contentLength = 10L;
+        final String contentRange = "bytes 10-20/100";
+        final InputStream inputStream = ResponseInputStream.nullInputStream();
+
+        final S3AsyncClient s3AsyncClient = mock(S3AsyncClient.class);
+        final S3BlobStore blobStore = mock(S3BlobStore.class);
+        final BlobPath blobPath = new BlobPath();
+        when(blobStore.bucket()).thenReturn(bucketName);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
+        when(blobStore.serverSideEncryption()).thenReturn(false);
+        final S3BlobContainer blobContainer = new S3BlobContainer(blobPath, blobStore);
+
+        GetObjectResponse getObjectResponse = GetObjectResponse.builder().contentLength(contentLength).contentRange(contentRange).build();
+
+        CompletableFuture<ResponseInputStream<GetObjectResponse>> getObjectPartResponse = new CompletableFuture<>();
+        ResponseInputStream<GetObjectResponse> responseInputStream = new ResponseInputStream<>(getObjectResponse, inputStream);
+        getObjectPartResponse.complete(responseInputStream);
+
+        when(
+            s3AsyncClient.getObject(
+                any(GetObjectRequest.class),
+                ArgumentMatchers.<AsyncResponseTransformer<GetObjectResponse, ResponseInputStream<GetObjectResponse>>>any()
+            )
+        ).thenReturn(getObjectPartResponse);
+
+        // Header based offset in case of a multi part object request
+        InputStreamContainer inputStreamContainer = blobContainer.getBlobPartInputStreamContainer(s3AsyncClient, bucketName, blobName, 0)
+            .get();
+
+        assertEquals(10, inputStreamContainer.getOffset());
+        assertEquals(contentLength, inputStreamContainer.getContentLength());
+        assertEquals(inputStream.available(), inputStreamContainer.getInputStream().available());
+
+        // 0 offset in case of a single part object request
+        inputStreamContainer = blobContainer.getBlobPartInputStreamContainer(s3AsyncClient, bucketName, blobName, null).get();
+
+        assertEquals(0, inputStreamContainer.getOffset());
+        assertEquals(contentLength, inputStreamContainer.getContentLength());
+        assertEquals(inputStream.available(), inputStreamContainer.getInputStream().available());
+    }
+
+    public void testTransformResponseToInputStreamContainer() throws Exception {
+        final String contentRange = "bytes 0-10/100";
+        final long contentLength = 10L;
+        final InputStream inputStream = ResponseInputStream.nullInputStream();
+
+        GetObjectResponse getObjectResponse = GetObjectResponse.builder().contentLength(contentLength).build();
+
+        // Exception when content range absent for multipart object
+        ResponseInputStream<GetObjectResponse> responseInputStreamNoRange = new ResponseInputStream<>(getObjectResponse, inputStream);
+        assertThrows(SdkException.class, () -> S3BlobContainer.transformResponseToInputStreamContainer(responseInputStreamNoRange, true));
+
+        // No exception when content range absent for single part object
+        ResponseInputStream<GetObjectResponse> responseInputStreamNoRangeSinglePart = new ResponseInputStream<>(
+            getObjectResponse,
+            inputStream
+        );
+        InputStreamContainer inputStreamContainer = S3BlobContainer.transformResponseToInputStreamContainer(
+            responseInputStreamNoRangeSinglePart,
+            false
+        );
+        assertEquals(contentLength, inputStreamContainer.getContentLength());
+        assertEquals(0, inputStreamContainer.getOffset());
+
+        // Exception when length is absent
+        getObjectResponse = GetObjectResponse.builder().contentRange(contentRange).build();
+        ResponseInputStream<GetObjectResponse> responseInputStreamNoContentLength = new ResponseInputStream<>(
+            getObjectResponse,
+            inputStream
+        );
+        assertThrows(
+            SdkException.class,
+            () -> S3BlobContainer.transformResponseToInputStreamContainer(responseInputStreamNoContentLength, true)
+        );
+
+        // No exception when range and length both are present
+        getObjectResponse = GetObjectResponse.builder().contentRange(contentRange).contentLength(contentLength).build();
+        ResponseInputStream<GetObjectResponse> responseInputStream = new ResponseInputStream<>(getObjectResponse, inputStream);
+        inputStreamContainer = S3BlobContainer.transformResponseToInputStreamContainer(responseInputStream, true);
+        assertEquals(contentLength, inputStreamContainer.getContentLength());
+        assertEquals(0, inputStreamContainer.getOffset());
+        assertEquals(inputStream.available(), inputStreamContainer.getInputStream().available());
+    }
+
+    private void mockObjectResponse(S3AsyncClient s3AsyncClient, String bucketName, String blobName, int objectSize) {
+
+        final InputStream inputStream = new ByteArrayInputStream(randomByteArrayOfLength(objectSize));
+
+        GetObjectResponse getObjectResponse = GetObjectResponse.builder().contentLength((long) objectSize).build();
+
+        CompletableFuture<ResponseInputStream<GetObjectResponse>> getObjectPartResponse = new CompletableFuture<>();
+        ResponseInputStream<GetObjectResponse> responseInputStream = new ResponseInputStream<>(getObjectResponse, inputStream);
+        getObjectPartResponse.complete(responseInputStream);
+
+        GetObjectRequest getObjectRequest = GetObjectRequest.builder().bucket(bucketName).key(blobName).build();
+
+        when(
+            s3AsyncClient.getObject(
+                eq(getObjectRequest),
+                ArgumentMatchers.<AsyncResponseTransformer<GetObjectResponse, ResponseInputStream<GetObjectResponse>>>any()
+            )
+        ).thenReturn(getObjectPartResponse);
+
+    }
+
+    private void mockObjectPartResponse(
+        S3AsyncClient s3AsyncClient,
+        String bucketName,
+        String blobName,
+        int totalNumberOfParts,
+        int partSize,
+        long objectSize
+    ) {
+        for (int partNumber = 1; partNumber <= totalNumberOfParts; partNumber++) {
+            final int start = (partNumber - 1) * partSize;
+            final int end = partNumber * partSize;
+            final String contentRange = "bytes " + start + "-" + end + "/" + objectSize;
+            final InputStream inputStream = new ByteArrayInputStream(randomByteArrayOfLength(partSize));
+
+            GetObjectResponse getObjectResponse = GetObjectResponse.builder()
+                .contentLength((long) partSize)
+                .contentRange(contentRange)
+                .build();
+
+            CompletableFuture<ResponseInputStream<GetObjectResponse>> getObjectPartResponse = new CompletableFuture<>();
+            ResponseInputStream<GetObjectResponse> responseInputStream = new ResponseInputStream<>(getObjectResponse, inputStream);
+            getObjectPartResponse.complete(responseInputStream);
+
+            GetObjectRequest getObjectRequest = GetObjectRequest.builder().bucket(bucketName).key(blobName).partNumber(partNumber).build();
+
+            when(
+                s3AsyncClient.getObject(
+                    eq(getObjectRequest),
+                    ArgumentMatchers.<AsyncResponseTransformer<GetObjectResponse, ResponseInputStream<GetObjectResponse>>>any()
+                )
+            ).thenReturn(getObjectPartResponse);
+        }
+    }
+
+    private static class CountingCompletionListener<T> implements ActionListener<T> {
+        private int responseCount;
+        private int failureCount;
+        private T response;
+        private Exception exception;
+
+        @Override
+        public void onResponse(T response) {
+            this.response = response;
+            responseCount++;
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            exception = e;
+            failureCount++;
+        }
+
+        public int getResponseCount() {
+            return responseCount;
+        }
+
+        public int getFailureCount() {
+            return failureCount;
+        }
+
+        public T getResponse() {
+            return response;
+        }
+
+        public Exception getException() {
+            return exception;
+        }
+    }
 }
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ClientSettingsTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ClientSettingsTests.java
index 462ed5377ff9a..61c9c998b1dec 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ClientSettingsTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ClientSettingsTests.java
@@ -32,27 +32,36 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.ClientConfiguration;
-import com.amazonaws.Protocol;
-import com.amazonaws.services.s3.AmazonS3Client;
+import software.amazon.awssdk.auth.credentials.AwsCredentials;
+import software.amazon.awssdk.auth.credentials.AwsSessionCredentials;
+import software.amazon.awssdk.core.client.config.ClientOverrideConfiguration;
+import software.amazon.awssdk.core.client.config.SdkAdvancedClientOption;
+import software.amazon.awssdk.core.signer.Signer;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.s3.S3Client;
+
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.repositories.s3.utils.AwsRequestSigner;
+import org.opensearch.repositories.s3.utils.Protocol;
 
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 
+import static org.hamcrest.CoreMatchers.startsWith;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.emptyString;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.Matchers.sameInstance;
 
-public class S3ClientSettingsTests extends OpenSearchTestCase {
+public class S3ClientSettingsTests extends AbstractS3RepositoryTestCase {
     public void testThereIsADefaultClientByDefault() {
-        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(Settings.EMPTY);
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(Settings.EMPTY, configPath());
         assertThat(settings.keySet(), contains("default"));
 
         final S3ClientSettings defaultSettings = settings.get("default");
@@ -60,14 +69,19 @@ public void testThereIsADefaultClientByDefault() {
         assertThat(defaultSettings.endpoint, is(emptyString()));
         assertThat(defaultSettings.protocol, is(Protocol.HTTPS));
         assertThat(defaultSettings.proxySettings, is(ProxySettings.NO_PROXY_SETTINGS));
-        assertThat(defaultSettings.readTimeoutMillis, is(ClientConfiguration.DEFAULT_SOCKET_TIMEOUT));
-        assertThat(defaultSettings.maxRetries, is(ClientConfiguration.DEFAULT_RETRY_POLICY.getMaxErrorRetry()));
-        assertThat(defaultSettings.throttleRetries, is(ClientConfiguration.DEFAULT_THROTTLE_RETRIES));
+        assertThat(defaultSettings.readTimeoutMillis, is(50 * 1000));
+        assertThat(defaultSettings.requestTimeoutMillis, is(120 * 1000));
+        assertThat(defaultSettings.connectionTimeoutMillis, is(10 * 1000));
+        assertThat(defaultSettings.connectionTTLMillis, is(5 * 1000));
+        assertThat(defaultSettings.maxConnections, is(100));
+        assertThat(defaultSettings.maxRetries, is(3));
+        assertThat(defaultSettings.throttleRetries, is(true));
     }
 
     public void testDefaultClientSettingsCanBeSet() {
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.default.max_retries", 10).build()
+            Settings.builder().put("s3.client.default.max_retries", 10).build(),
+            configPath()
         );
         assertThat(settings.keySet(), contains("default"));
 
@@ -77,12 +91,13 @@ public void testDefaultClientSettingsCanBeSet() {
 
     public void testNondefaultClientCreatedBySettingItsSettings() {
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.another_client.max_retries", 10).build()
+            Settings.builder().put("s3.client.another_client.max_retries", 10).build(),
+            configPath()
         );
         assertThat(settings.keySet(), contains("default", "another_client"));
 
         final S3ClientSettings defaultSettings = settings.get("default");
-        assertThat(defaultSettings.maxRetries, is(ClientConfiguration.DEFAULT_RETRY_POLICY.getMaxErrorRetry()));
+        assertThat(defaultSettings.maxRetries, is(3));
 
         final S3ClientSettings anotherClientSettings = settings.get("another_client");
         assertThat(anotherClientSettings.maxRetries, is(10));
@@ -93,7 +108,7 @@ public void testRejectionOfLoneAccessKey() {
         secureSettings.setString("s3.client.default.access_key", "aws_key");
         final IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build())
+            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build(), configPath())
         );
         assertThat(e.getMessage(), is("Missing secret key for s3 client [default]"));
     }
@@ -103,7 +118,7 @@ public void testRejectionOfLoneSecretKey() {
         secureSettings.setString("s3.client.default.secret_key", "aws_key");
         final IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build())
+            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build(), configPath())
         );
         assertThat(e.getMessage(), is("Missing access key for s3 client [default]"));
     }
@@ -113,20 +128,92 @@ public void testRejectionOfLoneSessionToken() {
         secureSettings.setString("s3.client.default.session_token", "aws_key");
         final IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build())
+            () -> S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build(), configPath())
         );
         assertThat(e.getMessage(), is("Missing access key and secret key for s3 client [default]"));
     }
 
+    public void testIrsaCredentialsTypeWithIdentityTokenFile() {
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().put("s3.client.default.identity_token_file", "file").build(),
+            configPath()
+        );
+        final S3ClientSettings defaultSettings = settings.get("default");
+        final S3ClientSettings.IrsaCredentials credentials = defaultSettings.irsaCredentials;
+        assertThat(credentials.getIdentityTokenFile(), is("config/file"));
+        assertThat(credentials.getRoleArn(), is(nullValue()));
+        assertThat(credentials.getRoleSessionName(), startsWith("s3-sdk-java-"));
+    }
+
+    public void testIrsaCredentialsTypeRoleArn() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).build(),
+            configPath()
+        );
+        final S3ClientSettings defaultSettings = settings.get("default");
+        final S3ClientSettings.IrsaCredentials credentials = defaultSettings.irsaCredentials;
+        assertThat(credentials.getRoleArn(), is("role"));
+        assertThat(credentials.getRoleSessionName(), startsWith("s3-sdk-java-"));
+    }
+
+    public void testIrsaCredentialsTypeWithRoleArnAndRoleSessionName() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        secureSettings.setString("s3.client.default.role_session_name", "session");
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).build(),
+            configPath()
+        );
+        final S3ClientSettings defaultSettings = settings.get("default");
+        final S3ClientSettings.IrsaCredentials credentials = defaultSettings.irsaCredentials;
+        assertThat(credentials.getRoleArn(), is("role"));
+        assertThat(credentials.getRoleSessionName(), is("session"));
+    }
+
+    public void testIrsaCredentialsTypeWithRoleArnAndRoleSessionNameAndIdentityTokeFileRelative() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        secureSettings.setString("s3.client.default.role_session_name", "session");
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).put("s3.client.default.identity_token_file", "file").build(),
+            configPath()
+        );
+        final S3ClientSettings defaultSettings = settings.get("default");
+        final S3ClientSettings.IrsaCredentials credentials = defaultSettings.irsaCredentials;
+        assertThat(credentials.getIdentityTokenFile(), is("config/file"));
+        assertThat(credentials.getRoleArn(), is("role"));
+        assertThat(credentials.getRoleSessionName(), is("session"));
+    }
+
+    public void testIrsaCredentialsTypeWithRoleArnAndRoleSessionNameAndIdentityTokeFileAbsolute() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        secureSettings.setString("s3.client.default.role_session_name", "session");
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).put("s3.client.default.identity_token_file", "/file").build(),
+            configPath()
+        );
+        final S3ClientSettings defaultSettings = settings.get("default");
+        final S3ClientSettings.IrsaCredentials credentials = defaultSettings.irsaCredentials;
+        assertThat(credentials.getIdentityTokenFile(), is("/file"));
+        assertThat(credentials.getRoleArn(), is("role"));
+        assertThat(credentials.getRoleSessionName(), is("session"));
+    }
+
     public void testCredentialsTypeWithAccessKeyAndSecretKey() {
         final MockSecureSettings secureSettings = new MockSecureSettings();
         secureSettings.setString("s3.client.default.access_key", "access_key");
         secureSettings.setString("s3.client.default.secret_key", "secret_key");
-        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build());
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).build(),
+            configPath()
+        );
         final S3ClientSettings defaultSettings = settings.get("default");
-        S3BasicCredentials credentials = defaultSettings.credentials;
-        assertThat(credentials.getAWSAccessKeyId(), is("access_key"));
-        assertThat(credentials.getAWSSecretKey(), is("secret_key"));
+        AwsCredentials credentials = defaultSettings.credentials;
+        assertThat(credentials.accessKeyId(), is("access_key"));
+        assertThat(credentials.secretAccessKey(), is("secret_key"));
     }
 
     public void testCredentialsTypeWithAccessKeyAndSecretKeyAndSessionToken() {
@@ -134,12 +221,15 @@ public void testCredentialsTypeWithAccessKeyAndSecretKeyAndSessionToken() {
         secureSettings.setString("s3.client.default.access_key", "access_key");
         secureSettings.setString("s3.client.default.secret_key", "secret_key");
         secureSettings.setString("s3.client.default.session_token", "session_token");
-        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build());
+        final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).build(),
+            configPath()
+        );
         final S3ClientSettings defaultSettings = settings.get("default");
-        S3BasicSessionCredentials credentials = (S3BasicSessionCredentials) defaultSettings.credentials;
-        assertThat(credentials.getAWSAccessKeyId(), is("access_key"));
-        assertThat(credentials.getAWSSecretKey(), is("secret_key"));
-        assertThat(credentials.getSessionToken(), is("session_token"));
+        AwsSessionCredentials credentials = (AwsSessionCredentials) defaultSettings.credentials;
+        assertThat(credentials.accessKeyId(), is("access_key"));
+        assertThat(credentials.secretAccessKey(), is("secret_key"));
+        assertThat(credentials.sessionToken(), is("session_token"));
     }
 
     public void testRefineWithRepoSettings() {
@@ -147,8 +237,10 @@ public void testRefineWithRepoSettings() {
         secureSettings.setString("s3.client.default.access_key", "access_key");
         secureSettings.setString("s3.client.default.secret_key", "secret_key");
         secureSettings.setString("s3.client.default.session_token", "session_token");
-        final S3ClientSettings baseSettings = S3ClientSettings.load(Settings.builder().setSecureSettings(secureSettings).build())
-            .get("default");
+        final S3ClientSettings baseSettings = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).build(),
+            configPath()
+        ).get("default");
 
         {
             final S3ClientSettings refinedSettings = baseSettings.refine(Settings.EMPTY);
@@ -159,25 +251,26 @@ public void testRefineWithRepoSettings() {
             final String endpoint = "some.host";
             final S3ClientSettings refinedSettings = baseSettings.refine(Settings.builder().put("endpoint", endpoint).build());
             assertThat(refinedSettings.endpoint, is(endpoint));
-            S3BasicSessionCredentials credentials = (S3BasicSessionCredentials) refinedSettings.credentials;
-            assertThat(credentials.getAWSAccessKeyId(), is("access_key"));
-            assertThat(credentials.getAWSSecretKey(), is("secret_key"));
-            assertThat(credentials.getSessionToken(), is("session_token"));
+            AwsSessionCredentials credentials = (AwsSessionCredentials) refinedSettings.credentials;
+            assertThat(credentials.accessKeyId(), is("access_key"));
+            assertThat(credentials.secretAccessKey(), is("secret_key"));
+            assertThat(credentials.sessionToken(), is("session_token"));
         }
 
         {
             final S3ClientSettings refinedSettings = baseSettings.refine(Settings.builder().put("path_style_access", true).build());
             assertThat(refinedSettings.pathStyleAccess, is(true));
-            S3BasicSessionCredentials credentials = (S3BasicSessionCredentials) refinedSettings.credentials;
-            assertThat(credentials.getAWSAccessKeyId(), is("access_key"));
-            assertThat(credentials.getAWSSecretKey(), is("secret_key"));
-            assertThat(credentials.getSessionToken(), is("session_token"));
+            AwsSessionCredentials credentials = (AwsSessionCredentials) refinedSettings.credentials;
+            assertThat(credentials.accessKeyId(), is("access_key"));
+            assertThat(credentials.secretAccessKey(), is("secret_key"));
+            assertThat(credentials.sessionToken(), is("session_token"));
         }
     }
 
     public void testPathStyleAccessCanBeSet() {
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.other.path_style_access", true).build()
+            Settings.builder().put("s3.client.other.path_style_access", true).build(),
+            configPath()
         );
         assertThat(settings.get("default").pathStyleAccess, is(false));
         assertThat(settings.get("other").pathStyleAccess, is(true));
@@ -185,36 +278,51 @@ public void testPathStyleAccessCanBeSet() {
 
     public void testUseChunkedEncodingCanBeSet() {
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.other.disable_chunked_encoding", true).build()
+            Settings.builder().put("s3.client.other.disable_chunked_encoding", true).build(),
+            configPath()
         );
         assertThat(settings.get("default").disableChunkedEncoding, is(false));
         assertThat(settings.get("other").disableChunkedEncoding, is(true));
     }
 
     public void testRegionCanBeSet() {
-        final String region = randomAlphaOfLength(5);
+        final String region = randomFrom(Region.regions().stream().map(Region::toString).toArray(String[]::new));
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.other.region", region).build()
+            Settings.builder().put("s3.client.other.region", region).build(),
+            configPath()
         );
         assertThat(settings.get("default").region, is(""));
         assertThat(settings.get("other").region, is(region));
-        try (S3Service s3Service = new S3Service()) {
-            AmazonS3Client other = (AmazonS3Client) s3Service.buildClient(settings.get("other"));
-            assertThat(other.getSignerRegionOverride(), is(region));
+        try (
+            S3Service s3Service = new S3Service(configPath());
+            S3Client other = SocketAccess.doPrivileged(() -> s3Service.buildClient(settings.get("other")).client());
+        ) {
+            assertThat(other.serviceClientConfiguration().region(), is(Region.of(region)));
         }
     }
 
     public void testSignerOverrideCanBeSet() {
-        final String signerOverride = randomAlphaOfLength(5);
+        S3Service.setDefaultAwsProfilePath();
+        final String signerOverride = randomFrom(AwsRequestSigner.values()).getName();
         final Map<String, S3ClientSettings> settings = S3ClientSettings.load(
-            Settings.builder().put("s3.client.other.signer_override", signerOverride).build()
+            Settings.builder().put("s3.client.other.signer_override", signerOverride).build(),
+            configPath()
         );
         assertThat(settings.get("default").region, is(""));
         assertThat(settings.get("other").signerOverride, is(signerOverride));
-        ClientConfiguration defaultConfiguration = S3Service.buildConfiguration(settings.get("default"));
-        assertThat(defaultConfiguration.getSignerOverride(), nullValue());
-        ClientConfiguration configuration = S3Service.buildConfiguration(settings.get("other"));
-        assertThat(configuration.getSignerOverride(), is(signerOverride));
+
+        ClientOverrideConfiguration defaultConfiguration = SocketAccess.doPrivileged(
+            () -> S3Service.buildOverrideConfiguration(settings.get("default"))
+        );
+        Optional<Signer> defaultSigner = defaultConfiguration.advancedOption(SdkAdvancedClientOption.SIGNER);
+        assertFalse(defaultSigner.isPresent());
+
+        ClientOverrideConfiguration configuration = SocketAccess.doPrivileged(
+            () -> S3Service.buildOverrideConfiguration(settings.get("other"))
+        );
+        Optional<Signer> otherSigner = configuration.advancedOption(SdkAdvancedClientOption.SIGNER);
+        assertTrue(otherSigner.isPresent());
+        assertThat(otherSigner.get(), sameInstance(AwsRequestSigner.fromSignerName(signerOverride).getSigner()));
     }
 
     public void testSetProxySettings() throws Exception {
@@ -234,7 +342,7 @@ public void testSetProxySettings() throws Exception {
             .setSecureSettings(secureSettings)
             .build();
 
-        final S3ClientSettings s3ClientSettings = S3ClientSettings.load(settings).get("default");
+        final S3ClientSettings s3ClientSettings = S3ClientSettings.load(settings, configPath()).get("default");
 
         assertEquals(ProxySettings.ProxyType.valueOf(proxyType.toUpperCase(Locale.ROOT)), s3ClientSettings.proxySettings.getType());
         assertEquals(new InetSocketAddress(InetAddress.getByName("127.0.0.10"), port), s3ClientSettings.proxySettings.getAddress());
@@ -248,7 +356,7 @@ public void testProxyWrongHost() {
             .put("s3.client.default.proxy.host", "thisisnotavalidhostorwehavebeensuperunlucky")
             .put("s3.client.default.proxy.port", 8080)
             .build();
-        final SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings));
+        final SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings, configPath()));
         assertEquals("S3 proxy host is unknown.", e.getMessage());
     }
 
@@ -258,7 +366,7 @@ public void testProxyTypeNotSet() {
             .put("s3.client.default.proxy.port", 8080)
             .build();
 
-        SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(hostPortSettings));
+        SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(hostPortSettings, configPath()));
         assertEquals("S3 proxy port or host or username or password have been set but proxy type is not defined.", e.getMessage());
 
         final MockSecureSettings secureSettings = new MockSecureSettings();
@@ -266,7 +374,7 @@ public void testProxyTypeNotSet() {
         secureSettings.setString("s3.client.default.proxy.password", "bbbb");
         final Settings usernamePasswordSettings = Settings.builder().setSecureSettings(secureSettings).build();
 
-        e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(usernamePasswordSettings));
+        e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(usernamePasswordSettings, configPath()));
         assertEquals("S3 proxy port or host or username or password have been set but proxy type is not defined.", e.getMessage());
     }
 
@@ -275,7 +383,7 @@ public void testProxyHostNotSet() {
             .put("s3.client.default.proxy.port", 8080)
             .put("s3.client.default.proxy.type", randomFrom("socks", "http", "https"))
             .build();
-        final SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings));
+        final SettingsException e = expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings, configPath()));
         assertEquals("S3 proxy type has been set but proxy host or port is not defined.", e.getMessage());
     }
 
@@ -286,7 +394,6 @@ public void testSocksDoesNotSupportForHttpProtocol() {
             .put("s3.client.default.protocol", "http")
             .put("s3.client.default.proxy.type", "socks")
             .build();
-        expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings));
+        expectThrows(SettingsException.class, () -> S3ClientSettings.load(settings, configPath()));
     }
-
 }
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RepositoryTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RepositoryTests.java
index da1f5d71b4da5..e65ca69a5047b 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RepositoryTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RepositoryTests.java
@@ -32,19 +32,24 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.services.s3.AbstractAmazonS3;
+import software.amazon.awssdk.services.s3.S3Client;
+
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.RepositoryException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
+import java.nio.file.Path;
+import java.util.List;
 import java.util.Map;
 
 import static org.hamcrest.Matchers.containsString;
@@ -52,20 +57,16 @@
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
 
-public class S3RepositoryTests extends OpenSearchTestCase {
-
-    private static class DummyS3Client extends AbstractAmazonS3 {
+public class S3RepositoryTests extends OpenSearchTestCase implements ConfigPathSupport {
 
-        @Override
-        public void shutdown() {
-            // TODO check is closed
+    private static class DummyS3Service extends S3Service {
+        DummyS3Service(final Path configPath) {
+            super(configPath);
         }
-    }
 
-    private static class DummyS3Service extends S3Service {
         @Override
         public AmazonS3Reference client(RepositoryMetadata repositoryMetadata) {
-            return new AmazonS3Reference(new DummyS3Client());
+            return new AmazonS3Reference(S3Client.create());
         }
 
         @Override
@@ -124,7 +125,8 @@ public void testBasePathSetting() {
     }
 
     public void testDefaultBufferSize() {
-        final RepositoryMetadata metadata = new RepositoryMetadata("dummy-repo", "mock", Settings.EMPTY);
+        Settings settings = Settings.builder().build();
+        final RepositoryMetadata metadata = new RepositoryMetadata("dummy-repo", "mock", settings);
         try (S3Repository s3repo = createS3Repo(metadata)) {
             assertThat(s3repo.getBlobStore(), is(nullValue()));
             s3repo.start();
@@ -135,13 +137,38 @@ public void testDefaultBufferSize() {
         }
     }
 
+    public void testIsReloadable() {
+        final RepositoryMetadata metadata = new RepositoryMetadata("dummy-repo", "mock", Settings.EMPTY);
+        try (S3Repository s3repo = createS3Repo(metadata)) {
+            assertTrue(s3repo.isReloadable());
+        }
+    }
+
+    public void testRestrictedSettingsDefault() {
+        final RepositoryMetadata metadata = new RepositoryMetadata("dummy-repo", "mock", Settings.EMPTY);
+        try (S3Repository s3repo = createS3Repo(metadata)) {
+            List<Setting<?>> restrictedSettings = s3repo.getRestrictedSystemRepositorySettings();
+            assertThat(restrictedSettings.size(), is(5));
+            assertTrue(restrictedSettings.contains(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING));
+            assertTrue(restrictedSettings.contains(BlobStoreRepository.READONLY_SETTING));
+            assertTrue(restrictedSettings.contains(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY));
+            assertTrue(restrictedSettings.contains(S3Repository.BUCKET_SETTING));
+            assertTrue(restrictedSettings.contains(S3Repository.BASE_PATH_SETTING));
+        }
+    }
+
     private S3Repository createS3Repo(RepositoryMetadata metadata) {
         return new S3Repository(
             metadata,
             NamedXContentRegistry.EMPTY,
-            new DummyS3Service(),
+            new DummyS3Service(configPath()),
             BlobStoreTestUtil.mockClusterService(),
-            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            null,
+            null,
+            null,
+            null,
+            false
         ) {
             @Override
             protected void assertSnapshotOrGenericThread() {
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RetryingInputStreamTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RetryingInputStreamTests.java
index 0f40a7b3392e8..b38d5119b4108 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RetryingInputStreamTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3RetryingInputStreamTests.java
@@ -32,12 +32,11 @@
 
 package org.opensearch.repositories.s3;
 
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.s3.model.GetObjectRequest;
-import com.amazonaws.services.s3.model.S3Object;
-import com.amazonaws.services.s3.model.S3ObjectInputStream;
-import org.apache.http.client.methods.HttpGet;
-import org.opensearch.common.Nullable;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+
 import org.opensearch.common.io.Streams;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -55,7 +54,7 @@ public class S3RetryingInputStreamTests extends OpenSearchTestCase {
     public void testInputStreamFullyConsumed() throws IOException {
         final byte[] expectedBytes = randomByteArrayOfLength(randomIntBetween(1, 512));
 
-        final S3RetryingInputStream stream = createInputStream(expectedBytes, null, null);
+        final S3RetryingInputStream stream = createInputStream(expectedBytes, 0L, (long) (Integer.MAX_VALUE - 1));
         Streams.consumeFully(stream);
 
         assertThat(stream.isEof(), is(true));
@@ -66,7 +65,7 @@ public void testInputStreamIsAborted() throws IOException {
         final byte[] expectedBytes = randomByteArrayOfLength(randomIntBetween(10, 512));
         final byte[] actualBytes = new byte[randomIntBetween(1, Math.max(1, expectedBytes.length - 1))];
 
-        final S3RetryingInputStream stream = createInputStream(expectedBytes, null, null);
+        final S3RetryingInputStream stream = createInputStream(expectedBytes, 0L, (long) (Integer.MAX_VALUE - 1));
         stream.read(actualBytes);
         stream.close();
 
@@ -77,8 +76,8 @@ public void testInputStreamIsAborted() throws IOException {
 
     public void testRangeInputStreamFullyConsumed() throws IOException {
         final byte[] bytes = randomByteArrayOfLength(randomIntBetween(1, 512));
-        final int position = randomIntBetween(0, bytes.length - 1);
-        final int length = randomIntBetween(1, bytes.length - position);
+        final long position = randomLongBetween(0, bytes.length - 1);
+        final long length = randomLongBetween(1, bytes.length - position);
 
         final S3RetryingInputStream stream = createInputStream(bytes, position, length);
         Streams.consumeFully(stream);
@@ -91,36 +90,33 @@ public void testRangeInputStreamIsAborted() throws IOException {
         final byte[] expectedBytes = randomByteArrayOfLength(randomIntBetween(10, 512));
         final byte[] actualBytes = new byte[randomIntBetween(1, Math.max(1, expectedBytes.length - 1))];
 
-        final int length = randomIntBetween(actualBytes.length + 1, expectedBytes.length);
-        final int position = randomIntBetween(0, Math.max(1, expectedBytes.length - length));
+        final long length = randomLongBetween(actualBytes.length + 1, expectedBytes.length);
+        final long position = randomLongBetween(0L, Math.max(1, expectedBytes.length - length));
 
         final S3RetryingInputStream stream = createInputStream(expectedBytes, position, length);
         stream.read(actualBytes);
         stream.close();
 
-        assertArrayEquals(Arrays.copyOfRange(expectedBytes, position, position + actualBytes.length), actualBytes);
+        assertArrayEquals(Arrays.copyOfRange(expectedBytes, (int) position, (int) (position + actualBytes.length)), actualBytes);
         assertThat(stream.isEof(), is(false));
         assertThat(stream.isAborted(), is(true));
     }
 
-    private S3RetryingInputStream createInputStream(final byte[] data, @Nullable final Integer position, @Nullable final Integer length)
-        throws IOException {
-        final S3Object s3Object = new S3Object();
-        final AmazonS3 client = mock(AmazonS3.class);
-        when(client.getObject(any(GetObjectRequest.class))).thenReturn(s3Object);
+    private S3RetryingInputStream createInputStream(final byte[] data, final Long start, final Long length) throws IOException {
+        final long end = Math.addExact(start, length - 1);
+        final S3Client client = mock(S3Client.class);
+        when(client.getObject(any(GetObjectRequest.class))).thenReturn(
+            new ResponseInputStream<>(
+                GetObjectResponse.builder().contentLength(length).build(),
+                new ByteArrayInputStream(data, Math.toIntExact(start), Math.toIntExact(length))
+            )
+        );
         final AmazonS3Reference clientReference = mock(AmazonS3Reference.class);
         when(clientReference.get()).thenReturn(client);
         final S3BlobStore blobStore = mock(S3BlobStore.class);
         when(blobStore.clientReference()).thenReturn(clientReference);
+        when(blobStore.getStatsMetricPublisher()).thenReturn(new StatsMetricPublisher());
 
-        if (position != null && length != null) {
-            s3Object.getObjectMetadata().setContentLength(length);
-            s3Object.setObjectContent(new S3ObjectInputStream(new ByteArrayInputStream(data, position, length), new HttpGet()));
-            return new S3RetryingInputStream(blobStore, "_blob", position, Math.addExact(position, length - 1));
-        } else {
-            s3Object.getObjectMetadata().setContentLength(data.length);
-            s3Object.setObjectContent(new S3ObjectInputStream(new ByteArrayInputStream(data), new HttpGet()));
-            return new S3RetryingInputStream(blobStore, "_blob");
-        }
+        return new S3RetryingInputStream(blobStore, "_blob", start, end);
     }
 }
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ServiceTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ServiceTests.java
index cb0e76e272b4e..400905eec8b1c 100644
--- a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ServiceTests.java
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/S3ServiceTests.java
@@ -32,24 +32,50 @@
 package org.opensearch.repositories.s3;
 
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-
+import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.test.OpenSearchTestCase;
 
-public class S3ServiceTests extends OpenSearchTestCase {
+import java.util.Map;
 
+public class S3ServiceTests extends AbstractS3RepositoryTestCase {
     public void testCachedClientsAreReleased() {
-        final S3Service s3Service = new S3Service();
-        final Settings settings = Settings.builder().put("endpoint", "http://first").build();
+        final S3Service s3Service = new S3Service(configPath());
+        final Settings settings = Settings.builder().put("endpoint", "http://first").put("region", "region").build();
+        final RepositoryMetadata metadata1 = new RepositoryMetadata("first", "s3", settings);
+        final RepositoryMetadata metadata2 = new RepositoryMetadata("second", "s3", settings);
+        final S3ClientSettings clientSettings = s3Service.settings(metadata2);
+        final S3ClientSettings otherClientSettings = s3Service.settings(metadata2);
+        assertSame(clientSettings, otherClientSettings);
+        final AmazonS3Reference reference = SocketAccess.doPrivileged(() -> s3Service.client(metadata1));
+        reference.close();
+        s3Service.close();
+        final AmazonS3Reference referenceReloaded = SocketAccess.doPrivileged(() -> s3Service.client(metadata1));
+        assertNotSame(referenceReloaded, reference);
+        referenceReloaded.close();
+        s3Service.close();
+        final S3ClientSettings clientSettingsReloaded = s3Service.settings(metadata1);
+        assertNotSame(clientSettings, clientSettingsReloaded);
+    }
+
+    public void testCachedClientsWithCredentialsAreReleased() {
+        final MockSecureSettings secureSettings = new MockSecureSettings();
+        secureSettings.setString("s3.client.default.role_arn", "role");
+        final Map<String, S3ClientSettings> defaults = S3ClientSettings.load(
+            Settings.builder().setSecureSettings(secureSettings).put("s3.client.default.identity_token_file", "file").build(),
+            configPath()
+        );
+        final S3Service s3Service = new S3Service(configPath());
+        s3Service.refreshAndClearCache(defaults);
+        final Settings settings = Settings.builder().put("endpoint", "http://first").put("region", "us-east-2").build();
         final RepositoryMetadata metadata1 = new RepositoryMetadata("first", "s3", settings);
         final RepositoryMetadata metadata2 = new RepositoryMetadata("second", "s3", settings);
         final S3ClientSettings clientSettings = s3Service.settings(metadata2);
         final S3ClientSettings otherClientSettings = s3Service.settings(metadata2);
         assertSame(clientSettings, otherClientSettings);
-        final AmazonS3Reference reference = s3Service.client(metadata1);
+        final AmazonS3Reference reference = SocketAccess.doPrivileged(() -> s3Service.client(metadata1));
         reference.close();
         s3Service.close();
-        final AmazonS3Reference referenceReloaded = s3Service.client(metadata1);
+        final AmazonS3Reference referenceReloaded = SocketAccess.doPrivileged(() -> s3Service.client(metadata1));
         assertNotSame(referenceReloaded, reference);
         referenceReloaded.close();
         s3Service.close();
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/async/AsyncTransferManagerTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/async/AsyncTransferManagerTests.java
new file mode 100644
index 0000000000000..9c07b929052bc
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/async/AsyncTransferManagerTests.java
@@ -0,0 +1,239 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.async;
+
+import software.amazon.awssdk.awscore.exception.AwsErrorDetails;
+import software.amazon.awssdk.core.async.AsyncRequestBody;
+import software.amazon.awssdk.http.HttpStatusCode;
+import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.AbortMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
+import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
+import software.amazon.awssdk.services.s3.model.DeleteObjectResponse;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectResponse;
+import software.amazon.awssdk.services.s3.model.S3Exception;
+import software.amazon.awssdk.services.s3.model.UploadPartRequest;
+import software.amazon.awssdk.services.s3.model.UploadPartResponse;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.exception.CorruptFileException;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.repositories.blobstore.ZeroInputStream;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executors;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class AsyncTransferManagerTests extends OpenSearchTestCase {
+
+    private AsyncTransferManager asyncTransferManager;
+    private S3AsyncClient s3AsyncClient;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        s3AsyncClient = mock(S3AsyncClient.class);
+        asyncTransferManager = new AsyncTransferManager(
+            ByteSizeUnit.MB.toBytes(5),
+            Executors.newSingleThreadExecutor(),
+            Executors.newSingleThreadExecutor()
+        );
+        super.setUp();
+    }
+
+    public void testOneChunkUpload() {
+        CompletableFuture<PutObjectResponse> putObjectResponseCompletableFuture = new CompletableFuture<>();
+        putObjectResponseCompletableFuture.complete(PutObjectResponse.builder().build());
+        when(s3AsyncClient.putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class))).thenReturn(
+            putObjectResponseCompletableFuture
+        );
+
+        CompletableFuture<Void> resultFuture = asyncTransferManager.uploadObject(
+            s3AsyncClient,
+            new UploadRequest("bucket", "key", ByteSizeUnit.MB.toBytes(1), WritePriority.HIGH, uploadSuccess -> {
+                // do nothing
+            }, false, null),
+            new StreamContext(
+                (partIdx, partSize, position) -> new InputStreamContainer(new ZeroInputStream(partSize), partSize, position),
+                ByteSizeUnit.MB.toBytes(1),
+                ByteSizeUnit.MB.toBytes(1),
+                1
+            )
+        );
+
+        try {
+            resultFuture.get();
+        } catch (ExecutionException | InterruptedException e) {
+            fail("did not expect resultFuture to fail");
+        }
+
+        verify(s3AsyncClient, times(1)).putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class));
+    }
+
+    public void testOneChunkUploadCorruption() {
+        CompletableFuture<PutObjectResponse> putObjectResponseCompletableFuture = new CompletableFuture<>();
+        putObjectResponseCompletableFuture.completeExceptionally(
+            S3Exception.builder()
+                .statusCode(HttpStatusCode.BAD_REQUEST)
+                .awsErrorDetails(AwsErrorDetails.builder().errorCode("BadDigest").build())
+                .build()
+        );
+        when(s3AsyncClient.putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class))).thenReturn(
+            putObjectResponseCompletableFuture
+        );
+
+        CompletableFuture<DeleteObjectResponse> deleteObjectResponseCompletableFuture = new CompletableFuture<>();
+        deleteObjectResponseCompletableFuture.complete(DeleteObjectResponse.builder().build());
+        when(s3AsyncClient.deleteObject(any(DeleteObjectRequest.class))).thenReturn(deleteObjectResponseCompletableFuture);
+
+        CompletableFuture<Void> resultFuture = asyncTransferManager.uploadObject(
+            s3AsyncClient,
+            new UploadRequest("bucket", "key", ByteSizeUnit.MB.toBytes(1), WritePriority.HIGH, uploadSuccess -> {
+                // do nothing
+            }, false, null),
+            new StreamContext(
+                (partIdx, partSize, position) -> new InputStreamContainer(new ZeroInputStream(partSize), partSize, position),
+                ByteSizeUnit.MB.toBytes(1),
+                ByteSizeUnit.MB.toBytes(1),
+                1
+            )
+        );
+
+        try {
+            resultFuture.get();
+            fail("did not expect resultFuture to pass");
+        } catch (ExecutionException | InterruptedException e) {
+            Throwable throwable = ExceptionsHelper.unwrap(e, CorruptFileException.class);
+            assertNotNull(throwable);
+            assertTrue(throwable instanceof CorruptFileException);
+        }
+
+        verify(s3AsyncClient, times(1)).putObject(any(PutObjectRequest.class), any(AsyncRequestBody.class));
+        verify(s3AsyncClient, times(1)).deleteObject(any(DeleteObjectRequest.class));
+    }
+
+    public void testMultipartUpload() {
+        CompletableFuture<CreateMultipartUploadResponse> createMultipartUploadRequestCompletableFuture = new CompletableFuture<>();
+        createMultipartUploadRequestCompletableFuture.complete(CreateMultipartUploadResponse.builder().uploadId("uploadId").build());
+        when(s3AsyncClient.createMultipartUpload(any(CreateMultipartUploadRequest.class))).thenReturn(
+            createMultipartUploadRequestCompletableFuture
+        );
+
+        CompletableFuture<UploadPartResponse> uploadPartResponseCompletableFuture = new CompletableFuture<>();
+        uploadPartResponseCompletableFuture.complete(UploadPartResponse.builder().checksumCRC32("pzjqHA==").build());
+        when(s3AsyncClient.uploadPart(any(UploadPartRequest.class), any(AsyncRequestBody.class))).thenReturn(
+            uploadPartResponseCompletableFuture
+        );
+
+        CompletableFuture<CompleteMultipartUploadResponse> completeMultipartUploadResponseCompletableFuture = new CompletableFuture<>();
+        completeMultipartUploadResponseCompletableFuture.complete(CompleteMultipartUploadResponse.builder().build());
+        when(s3AsyncClient.completeMultipartUpload(any(CompleteMultipartUploadRequest.class))).thenReturn(
+            completeMultipartUploadResponseCompletableFuture
+        );
+
+        CompletableFuture<AbortMultipartUploadResponse> abortMultipartUploadResponseCompletableFuture = new CompletableFuture<>();
+        abortMultipartUploadResponseCompletableFuture.complete(AbortMultipartUploadResponse.builder().build());
+        when(s3AsyncClient.abortMultipartUpload(any(AbortMultipartUploadRequest.class))).thenReturn(
+            abortMultipartUploadResponseCompletableFuture
+        );
+
+        CompletableFuture<Void> resultFuture = asyncTransferManager.uploadObject(
+            s3AsyncClient,
+            new UploadRequest("bucket", "key", ByteSizeUnit.MB.toBytes(5), WritePriority.HIGH, uploadSuccess -> {
+                // do nothing
+            }, true, 3376132981L),
+            new StreamContext(
+                (partIdx, partSize, position) -> new InputStreamContainer(new ZeroInputStream(partSize), partSize, position),
+                ByteSizeUnit.MB.toBytes(1),
+                ByteSizeUnit.MB.toBytes(1),
+                5
+            )
+        );
+
+        try {
+            resultFuture.get();
+        } catch (ExecutionException | InterruptedException e) {
+            fail("did not expect resultFuture to fail");
+        }
+
+        verify(s3AsyncClient, times(1)).createMultipartUpload(any(CreateMultipartUploadRequest.class));
+        verify(s3AsyncClient, times(5)).uploadPart(any(UploadPartRequest.class), any(AsyncRequestBody.class));
+        verify(s3AsyncClient, times(1)).completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
+        verify(s3AsyncClient, times(0)).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
+    }
+
+    public void testMultipartUploadCorruption() {
+        CompletableFuture<CreateMultipartUploadResponse> createMultipartUploadRequestCompletableFuture = new CompletableFuture<>();
+        createMultipartUploadRequestCompletableFuture.complete(CreateMultipartUploadResponse.builder().uploadId("uploadId").build());
+        when(s3AsyncClient.createMultipartUpload(any(CreateMultipartUploadRequest.class))).thenReturn(
+            createMultipartUploadRequestCompletableFuture
+        );
+
+        CompletableFuture<UploadPartResponse> uploadPartResponseCompletableFuture = new CompletableFuture<>();
+        uploadPartResponseCompletableFuture.complete(UploadPartResponse.builder().checksumCRC32("pzjqHA==").build());
+        when(s3AsyncClient.uploadPart(any(UploadPartRequest.class), any(AsyncRequestBody.class))).thenReturn(
+            uploadPartResponseCompletableFuture
+        );
+
+        CompletableFuture<CompleteMultipartUploadResponse> completeMultipartUploadResponseCompletableFuture = new CompletableFuture<>();
+        completeMultipartUploadResponseCompletableFuture.complete(CompleteMultipartUploadResponse.builder().build());
+        when(s3AsyncClient.completeMultipartUpload(any(CompleteMultipartUploadRequest.class))).thenReturn(
+            completeMultipartUploadResponseCompletableFuture
+        );
+
+        CompletableFuture<AbortMultipartUploadResponse> abortMultipartUploadResponseCompletableFuture = new CompletableFuture<>();
+        abortMultipartUploadResponseCompletableFuture.complete(AbortMultipartUploadResponse.builder().build());
+        when(s3AsyncClient.abortMultipartUpload(any(AbortMultipartUploadRequest.class))).thenReturn(
+            abortMultipartUploadResponseCompletableFuture
+        );
+
+        CompletableFuture<Void> resultFuture = asyncTransferManager.uploadObject(
+            s3AsyncClient,
+            new UploadRequest("bucket", "key", ByteSizeUnit.MB.toBytes(5), WritePriority.HIGH, uploadSuccess -> {
+                // do nothing
+            }, true, 0L),
+            new StreamContext(
+                (partIdx, partSize, position) -> new InputStreamContainer(new ZeroInputStream(partSize), partSize, position),
+                ByteSizeUnit.MB.toBytes(1),
+                ByteSizeUnit.MB.toBytes(1),
+                5
+            )
+        );
+
+        try {
+            resultFuture.get();
+            fail("did not expect resultFuture to pass");
+        } catch (ExecutionException | InterruptedException e) {
+            Throwable throwable = ExceptionsHelper.unwrap(e, CorruptFileException.class);
+            assertNotNull(throwable);
+            assertTrue(throwable instanceof CorruptFileException);
+        }
+
+        verify(s3AsyncClient, times(1)).createMultipartUpload(any(CreateMultipartUploadRequest.class));
+        verify(s3AsyncClient, times(5)).uploadPart(any(UploadPartRequest.class), any(AsyncRequestBody.class));
+        verify(s3AsyncClient, times(0)).completeMultipartUpload(any(CompleteMultipartUploadRequest.class));
+        verify(s3AsyncClient, times(1)).abortMultipartUpload(any(AbortMultipartUploadRequest.class));
+    }
+}
diff --git a/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/utils/HttpRangeUtilsTests.java b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/utils/HttpRangeUtilsTests.java
new file mode 100644
index 0000000000000..9a4267c5266e5
--- /dev/null
+++ b/plugins/repository-s3/src/test/java/org/opensearch/repositories/s3/utils/HttpRangeUtilsTests.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.s3.utils;
+
+import software.amazon.awssdk.core.exception.SdkException;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public final class HttpRangeUtilsTests extends OpenSearchTestCase {
+
+    public void testFromHttpRangeHeader() {
+        String headerValue = "bytes 0-10/200";
+        Long offset = HttpRangeUtils.getStartOffsetFromRangeHeader(headerValue);
+        assertEquals(0L, offset.longValue());
+
+        headerValue = "bytes 0-10/*";
+        offset = HttpRangeUtils.getStartOffsetFromRangeHeader(headerValue);
+        assertEquals(0L, offset.longValue());
+
+        final String invalidHeaderValue = "bytes */*";
+        assertThrows(SdkException.class, () -> HttpRangeUtils.getStartOffsetFromRangeHeader(invalidHeaderValue));
+    }
+}
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/10_basic.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/10_basic.yml
index cde14321805f5..b35366d904263 100644
--- a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/10_basic.yml
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: repository-s3 } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: repository-s3 } }
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/20_repository_permanent_credentials.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/20_repository_permanent_credentials.yml
index a0c2d2e593a47..5590122e26b86 100644
--- a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/20_repository_permanent_credentials.yml
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/20_repository_permanent_credentials.yml
@@ -11,6 +11,7 @@ setup:
           type: s3
           settings:
             bucket: ${permanent_bucket}
+            region: ${permanent_region}
             client: integration_test_permanent
             base_path: "${permanent_base_path}"
             canned_acl: private
@@ -42,6 +43,7 @@ setup:
           type: s3
           settings:
             bucket: ${permanent_bucket}
+            region: ${permanent_region}
             client: integration_test_permanent
             base_path: "${permanent_base_path}"
             endpoint: 127.0.0.1:5
@@ -57,6 +59,7 @@ setup:
           type: s3
           settings:
             bucket: ${permanent_bucket}
+            region: ${permanent_region}
             client: integration_test_permanent
             base_path: "${permanent_base_path}"
             endpoint: 127.0.0.1:5
@@ -275,6 +278,7 @@ setup:
           type: s3
           settings:
             bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+            region: ${permanent_region}
             client: integration_test_permanent
 
 ---
@@ -288,6 +292,7 @@ setup:
           type: s3
           settings:
             bucket: repository_permanent
+            region: ${permanent_region}
             client: unknown
 
 ---
@@ -302,6 +307,7 @@ setup:
         settings:
           readonly: true
           bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+          region: ${permanent_region}
           client: integration_test_permanent
 
 ---
@@ -316,6 +322,7 @@ setup:
         settings:
           readonly: true
           bucket: repository_permanent
+          region: ${permanent_region}
           client: unknown
 
 ---
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/30_repository_temporary_credentials.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/30_repository_temporary_credentials.yml
index d26a07eec85dc..741e96110ea96 100644
--- a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/30_repository_temporary_credentials.yml
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/30_repository_temporary_credentials.yml
@@ -11,6 +11,7 @@ setup:
           type: s3
           settings:
             bucket: ${temporary_bucket}
+            region: ${temporary_region}
             client: integration_test_temporary
             base_path: "${temporary_base_path}"
             canned_acl: private
@@ -26,6 +27,7 @@ setup:
         repository: repository_temporary
 
   - match: { repository_temporary.settings.bucket : ${temporary_bucket} }
+  - match: { repository_temporary.settings.region : ${temporary_region} }
   - match: { repository_temporary.settings.client : "integration_test_temporary" }
   - match: { repository_temporary.settings.base_path : "${temporary_base_path}" }
   - match: { repository_temporary.settings.canned_acl : "private" }
@@ -185,6 +187,7 @@ setup:
           type: s3
           settings:
             bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+            region: ${temporary_region}
             client: integration_test_temporary
 
 ---
@@ -198,6 +201,7 @@ setup:
           type: s3
           settings:
             bucket: repository_temporary
+            region: ${temporary_region}
             client: unknown
 
 ---
@@ -212,6 +216,7 @@ setup:
         settings:
           readonly: true
           bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+          region: ${temporary_region}
           client: integration_test_temporary
 
 ---
@@ -226,6 +231,7 @@ setup:
         settings:
           readonly: true
           bucket: repository_temporary
+          region: ${temporary_region}
           client: unknown
 
 ---
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/40_repository_ec2_credentials.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/40_repository_ec2_credentials.yml
index 6d3b174b99863..8d4349845a1f6 100644
--- a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/40_repository_ec2_credentials.yml
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/40_repository_ec2_credentials.yml
@@ -11,6 +11,7 @@ setup:
           type: s3
           settings:
             bucket: ${ec2_bucket}
+            region: region
             client: integration_test_ec2
             base_path: "${ec2_base_path}"
             canned_acl: private
@@ -30,6 +31,7 @@ setup:
   - match: { repository_ec2.settings.base_path : "${ec2_base_path}" }
   - match: { repository_ec2.settings.canned_acl : "private" }
   - match: { repository_ec2.settings.storage_class : "standard" }
+  - is_false: repository_ec2.settings.region
   - is_false: repository_ec2.settings.access_key
   - is_false: repository_ec2.settings.secret_key
   - is_false: repository_ec2.settings.session_token
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/50_repository_ecs_credentials.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/50_repository_ecs_credentials.yml
index 79d1e3d9c3bbe..8650af2d29852 100644
--- a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/50_repository_ecs_credentials.yml
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/50_repository_ecs_credentials.yml
@@ -11,6 +11,7 @@ setup:
           type: s3
           settings:
             bucket: ${ecs_bucket}
+            region: region
             client: integration_test_ecs
             base_path: "${ecs_base_path}"
             canned_acl: private
@@ -30,6 +31,7 @@ setup:
   - match: { repository_ecs.settings.base_path : "${ecs_base_path}" }
   - match: { repository_ecs.settings.canned_acl : "private" }
   - match: { repository_ecs.settings.storage_class : "standard" }
+  - is_false: repository_ecs.settings.region
   - is_false: repository_ecs.settings.access_key
   - is_false: repository_ecs.settings.secret_key
   - is_false: repository_ecs.settings.session_token
diff --git a/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/60_repository_eks_credentials.yml b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/60_repository_eks_credentials.yml
new file mode 100644
index 0000000000000..e01d3e87eb35f
--- /dev/null
+++ b/plugins/repository-s3/src/yamlRestTest/resources/rest-api-spec/test/repository_s3/60_repository_eks_credentials.yml
@@ -0,0 +1,269 @@
+# Integration tests for repository-s3
+
+---
+setup:
+
+  # Register repository with eks credentials
+  - do:
+      snapshot.create_repository:
+        repository: repository_eks
+        body:
+          type: s3
+          settings:
+            bucket: ${eks_bucket}
+            region: region
+            client: integration_test_eks
+            base_path: "${eks_base_path}"
+            canned_acl: private
+            storage_class: standard
+            disable_chunked_encoding: ${disable_chunked_encoding}
+
+---
+"Snapshot and Restore with repository-s3 using eks credentials":
+
+  # Get repository
+  - do:
+      snapshot.get_repository:
+        repository: repository_eks
+
+  - match: { repository_eks.settings.bucket : ${eks_bucket} }
+  - match: { repository_eks.settings.client : "integration_test_eks" }
+  - match: { repository_eks.settings.base_path : "${eks_base_path}" }
+  - match: { repository_eks.settings.canned_acl : "private" }
+  - match: { repository_eks.settings.storage_class : "standard" }
+  - is_false: repository_eks.settings.access_key
+  - is_false: repository_eks.settings.secret_key
+  - is_false: repository_eks.settings.session_token
+  - is_false: repository_eks.settings.role_arn
+  - is_false: repository_eks.settings.role_session_name
+  - is_false: repository_eks.settings.identity_token_file
+
+  # Index documents
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: docs
+              _id:    1
+          - snapshot: one
+          - index:
+              _index: docs
+              _id:    2
+          - snapshot: one
+          - index:
+              _index: docs
+              _id:    3
+          - snapshot: one
+
+  - do:
+      count:
+        index: docs
+
+  - match: {count: 3}
+
+  # Create a first snapshot
+  - do:
+      snapshot.create:
+        repository: repository_eks
+        snapshot: snapshot-one
+        wait_for_completion: true
+
+  - match: { snapshot.snapshot: snapshot-one }
+  - match: { snapshot.state : SUCCESS }
+  - match: { snapshot.include_global_state: true }
+  - match: { snapshot.shards.failed : 0 }
+
+  - do:
+      snapshot.status:
+        repository: repository_eks
+        snapshot: snapshot-one
+
+  - is_true: snapshots
+  - match: { snapshots.0.snapshot: snapshot-one }
+  - match: { snapshots.0.state : SUCCESS }
+
+  # Index more documents
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: docs
+              _id:    4
+          - snapshot: two
+          - index:
+              _index: docs
+              _id:    5
+          - snapshot: two
+          - index:
+              _index: docs
+              _id:    6
+          - snapshot: two
+          - index:
+              _index: docs
+              _id:    7
+          - snapshot: two
+
+  - do:
+      count:
+        index: docs
+
+  - match: {count: 7}
+
+  # Create a second snapshot
+  - do:
+      snapshot.create:
+        repository: repository_eks
+        snapshot: snapshot-two
+        wait_for_completion: true
+
+  - match: { snapshot.snapshot: snapshot-two }
+  - match: { snapshot.state : SUCCESS }
+  - match: { snapshot.shards.failed : 0 }
+
+  - do:
+      snapshot.get:
+        repository: repository_eks
+        snapshot: snapshot-one,snapshot-two
+
+  - is_true: snapshots
+  - match: { snapshots.0.state : SUCCESS }
+  - match: { snapshots.1.state : SUCCESS }
+
+  # Delete the index
+  - do:
+      indices.delete:
+        index: docs
+
+  # Restore the second snapshot
+  - do:
+      snapshot.restore:
+        repository: repository_eks
+        snapshot: snapshot-two
+        wait_for_completion: true
+
+  - do:
+      count:
+        index: docs
+
+  - match: {count: 7}
+
+  # Delete the index again
+  - do:
+      indices.delete:
+        index: docs
+
+  # Restore the first snapshot
+  - do:
+      snapshot.restore:
+        repository: repository_eks
+        snapshot: snapshot-one
+        wait_for_completion: true
+
+  - do:
+      count:
+        index: docs
+
+  - match: {count: 3}
+
+  # Remove the snapshots
+  - do:
+      snapshot.delete:
+        repository: repository_eks
+        snapshot: snapshot-two
+
+  - do:
+      snapshot.delete:
+        repository: repository_eks
+        snapshot: snapshot-one
+
+---
+"Register a repository with a non existing bucket":
+
+  - do:
+      catch: /repository_verification_exception/
+      snapshot.create_repository:
+        repository: repository_eks
+        body:
+          type: s3
+          settings:
+            bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+            client: integration_test_eks
+
+---
+"Register a repository with a non existing client":
+
+  - do:
+      catch: /illegal_argument_exception/
+      snapshot.create_repository:
+        repository: repository_eks
+        body:
+          type: s3
+          settings:
+            bucket: repository_eks
+            client: unknown
+
+---
+"Register a read-only repository with a non existing bucket":
+
+- do:
+    catch: /repository_verification_exception/
+    snapshot.create_repository:
+      repository: repository_eks
+      body:
+        type: s3
+        settings:
+          readonly: true
+          bucket: zHHkfSqlbnBsbpSgvCYtxrEfFLqghXtyPvvvKPNBnRCicNHQLE
+          client: integration_test_eks
+
+---
+"Register a read-only repository with a non existing client":
+
+- do:
+    catch: /illegal_argument_exception/
+    snapshot.create_repository:
+      repository: repository_eks
+      body:
+        type: s3
+        settings:
+          readonly: true
+          bucket: repository_eks
+          client: unknown
+
+---
+"Get a non existing snapshot":
+
+  - do:
+      catch: /snapshot_missing_exception/
+      snapshot.get:
+        repository: repository_eks
+        snapshot: missing
+
+---
+"Delete a non existing snapshot":
+
+  - do:
+      catch: /snapshot_missing_exception/
+      snapshot.delete:
+        repository: repository_eks
+        snapshot: missing
+
+---
+"Restore a non existing snapshot":
+
+  - do:
+      catch: /snapshot_restore_exception/
+      snapshot.restore:
+        repository: repository_eks
+        snapshot: missing
+        wait_for_completion: true
+
+---
+teardown:
+
+  # Remove our repository
+  - do:
+     snapshot.delete_repository:
+       repository: repository_eks
diff --git a/plugins/store-smb/src/test/java/org/opensearch/index/store/SmbMMapDirectoryTests.java b/plugins/store-smb/src/test/java/org/opensearch/index/store/SmbMMapDirectoryTests.java
index 547f2f36a7643..2cac58262c75a 100644
--- a/plugins/store-smb/src/test/java/org/opensearch/index/store/SmbMMapDirectoryTests.java
+++ b/plugins/store-smb/src/test/java/org/opensearch/index/store/SmbMMapDirectoryTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.index.store;
 
-import java.io.IOException;
-import java.nio.file.Path;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.MMapDirectory;
 
+import java.io.IOException;
+import java.nio.file.Path;
+
 public class SmbMMapDirectoryTests extends OpenSearchBaseDirectoryTestCase {
 
     @Override
diff --git a/plugins/store-smb/src/yamlRestTest/resources/rest-api-spec/test/store_smb/10_basic.yml b/plugins/store-smb/src/yamlRestTest/resources/rest-api-spec/test/store_smb/10_basic.yml
index 8956b3a8c116f..d358c8980d245 100644
--- a/plugins/store-smb/src/yamlRestTest/resources/rest-api-spec/test/store_smb/10_basic.yml
+++ b/plugins/store-smb/src/yamlRestTest/resources/rest-api-spec/test/store_smb/10_basic.yml
@@ -7,10 +7,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - contains:  { nodes.$master.plugins: { name: store-smb } }
+    - contains:  { nodes.$cluster_manager.plugins: { name: store-smb } }
diff --git a/plugins/telemetry-otel/build.gradle b/plugins/telemetry-otel/build.gradle
new file mode 100644
index 0000000000000..04fff20947b4f
--- /dev/null
+++ b/plugins/telemetry-otel/build.gradle
@@ -0,0 +1,113 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+import org.apache.tools.ant.taskdefs.condition.Os
+import org.opensearch.gradle.Architecture
+import org.opensearch.gradle.OS
+import org.opensearch.gradle.info.BuildParams
+
+apply plugin: 'opensearch.internal-cluster-test'
+
+opensearchplugin {
+  description 'Opentelemetry based telemetry implementation.'
+  classname 'org.opensearch.telemetry.OTelTelemetryPlugin'
+  hasClientJar = true
+}
+
+dependencies {
+  api project(":libs:opensearch-telemetry")
+  api "io.opentelemetry:opentelemetry-api:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-context:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-sdk:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-sdk-common:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-sdk-trace:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-sdk-metrics:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-exporter-logging:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-semconv:${versions.opentelemetry}-alpha"
+  api "io.opentelemetry:opentelemetry-sdk-logs:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-exporter-otlp:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-exporter-common:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-exporter-otlp-common:${versions.opentelemetry}"
+  runtimeOnly "org.jetbrains.kotlin:kotlin-stdlib:${versions.kotlin}"
+  runtimeOnly "com.squareup.okhttp3:okhttp:4.11.0"
+  runtimeOnly "com.squareup.okio:okio-jvm:3.5.0"
+  runtimeOnly "io.opentelemetry:opentelemetry-exporter-sender-okhttp:${versions.opentelemetry}"
+  api "io.opentelemetry:opentelemetry-extension-incubator:${versions.opentelemetry}-alpha"
+  testImplementation "io.opentelemetry:opentelemetry-sdk-testing:${versions.opentelemetry}"
+}
+
+
+thirdPartyAudit {
+  ignoreViolations(
+   'io.opentelemetry.internal.shaded.jctools.queues.MpscArrayQueueConsumerIndexField',
+   'io.opentelemetry.internal.shaded.jctools.queues.MpscArrayQueueProducerIndexField',
+   'io.opentelemetry.internal.shaded.jctools.queues.MpscArrayQueueProducerLimitField',
+   'io.opentelemetry.internal.shaded.jctools.util.UnsafeAccess',
+   'io.opentelemetry.internal.shaded.jctools.util.UnsafeRefArrayAccess'
+  )
+
+  ignoreMissingClasses(
+    'android.net.http.X509TrustManagerExtensions',
+    'android.net.ssl.SSLSockets',
+    'android.os.Build$VERSION',
+    'android.security.NetworkSecurityPolicy',
+    'android.util.Log',
+    'com.google.common.io.ByteStreams',
+    'com.google.common.util.concurrent.ListenableFuture',
+    'io.grpc.CallOptions',
+    'io.grpc.Channel',
+    'io.grpc.Drainable',
+    'io.grpc.KnownLength',
+    'io.grpc.ManagedChannel',
+    'io.grpc.MethodDescriptor',
+    'io.grpc.MethodDescriptor$Builder',
+    'io.grpc.MethodDescriptor$Marshaller',
+    'io.grpc.MethodDescriptor$MethodType',
+    'io.grpc.stub.AbstractFutureStub',
+    'io.grpc.stub.AbstractStub',
+    'io.grpc.stub.ClientCalls',
+    'org.bouncycastle.jsse.BCSSLParameters',
+    'org.bouncycastle.jsse.BCSSLSocket',
+    'org.conscrypt.Conscrypt',
+    'org.conscrypt.Conscrypt$Version',
+    'org.conscrypt.ConscryptHostnameVerifier',
+    'org.openjsse.javax.net.ssl.SSLParameters',
+    'org.openjsse.javax.net.ssl.SSLSocket',
+    'io.opentelemetry.api.events.EventEmitter',
+    'io.opentelemetry.api.events.EventEmitterBuilder',
+    'io.opentelemetry.api.events.EventEmitterProvider',
+    'io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties',
+    'io.opentelemetry.sdk.autoconfigure.spi.logs.ConfigurableLogRecordExporterProvider',
+    'io.opentelemetry.sdk.autoconfigure.spi.metrics.ConfigurableMetricExporterProvider',
+    'io.opentelemetry.sdk.autoconfigure.spi.traces.ConfigurableSpanExporterProvider',
+    'kotlin.io.path.PathsKt',
+    'io.opentelemetry.sdk.autoconfigure.spi.traces.ConfigurableSpanExporterProvider'
+  )
+}
+
+tasks.named("bundlePlugin").configure {
+  from('config/telemetry-otel') {
+    into 'config'
+  }
+}
+
+tasks.register("writeTestJavaPolicy") {
+  doLast {
+    final File tmp = file("${buildDir}/tmp")
+    if (tmp.exists() == false && tmp.mkdirs() == false) {
+      throw new GradleException("failed to create temporary directory [${tmp}]")
+    }
+    final File javaPolicy = file("${tmp}/java.policy")
+    javaPolicy.write(
+      [
+        "grant {",
+        "  permission java.io.FilePermission \"config\", \"read\";",
+        "};"
+      ].join("\n"))
+  }
+}
diff --git a/plugins/telemetry-otel/config/telemetry-otel/log4j2.properties b/plugins/telemetry-otel/config/telemetry-otel/log4j2.properties
new file mode 100644
index 0000000000000..8dec1119eec66
--- /dev/null
+++ b/plugins/telemetry-otel/config/telemetry-otel/log4j2.properties
@@ -0,0 +1,47 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+
+
+appender.tracing.type = RollingFile
+appender.tracing.name = tracing
+appender.tracing.fileName = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_otel_traces.log
+appender.tracing.filePermissions = rw-r-----
+appender.tracing.layout.type = PatternLayout
+appender.tracing.layout.pattern = %m%n
+appender.tracing.filePattern = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_otel_traces-%i.log.gz
+appender.tracing.policies.type = Policies
+appender.tracing.policies.size.type = SizeBasedTriggeringPolicy
+appender.tracing.policies.size.size = 1GB
+appender.tracing.strategy.type = DefaultRolloverStrategy
+appender.tracing.strategy.max = 4
+
+
+logger.exporter.name = io.opentelemetry.exporter.logging.LoggingSpanExporter
+logger.exporter.level = INFO
+logger.exporter.appenderRef.tracing.ref = tracing
+logger.exporter.additivity = false
+
+
+appender.metrics.type = RollingFile
+appender.metrics.name = metrics
+appender.metrics.fileName = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_otel_metrics.log
+appender.metrics.filePermissions = rw-r-----
+appender.metrics.layout.type = PatternLayout
+appender.metrics.layout.pattern = %m%n
+appender.metrics.filePattern = ${sys:opensearch.logs.base_path}${sys:file.separator}${sys:opensearch.logs.cluster_name}_otel_metrics-%i.log.gz
+appender.metrics.policies.type = Policies
+appender.metrics.policies.size.type = SizeBasedTriggeringPolicy
+appender.metrics.policies.size.size = 1GB
+appender.metrics.strategy.type = DefaultRolloverStrategy
+appender.metrics.strategy.max = 4
+
+
+logger.metrics_exporter.name = io.opentelemetry.exporter.logging.LoggingMetricExporter
+logger.metrics_exporter.level = INFO
+logger.metrics_exporter.appenderRef.tracing.ref = metrics
+logger.metrics_exporter.additivity = false
diff --git a/plugins/telemetry-otel/licenses/kotlin-stdlib-1.7.10.jar.sha1 b/plugins/telemetry-otel/licenses/kotlin-stdlib-1.7.10.jar.sha1
new file mode 100644
index 0000000000000..4d119fbf4df70
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/kotlin-stdlib-1.7.10.jar.sha1
@@ -0,0 +1 @@
+d2abf9e77736acc4450dc4a3f707fa2c10f5099d
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/kotlin-stdlib-LICENSE.txt b/plugins/telemetry-otel/licenses/kotlin-stdlib-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/kotlin-stdlib-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/kotlin-stdlib-NOTICE.txt b/plugins/telemetry-otel/licenses/kotlin-stdlib-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/okhttp-4.11.0.jar.sha1 b/plugins/telemetry-otel/licenses/okhttp-4.11.0.jar.sha1
new file mode 100644
index 0000000000000..1fc0db6615cb5
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/okhttp-4.11.0.jar.sha1
@@ -0,0 +1 @@
+436932d695b2c43f2c86b8111c596179cd133d56
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/okhttp-LICENSE.txt b/plugins/telemetry-otel/licenses/okhttp-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/okhttp-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/okhttp-NOTICE.txt b/plugins/telemetry-otel/licenses/okhttp-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/okio-jvm-3.5.0.jar.sha1 b/plugins/telemetry-otel/licenses/okio-jvm-3.5.0.jar.sha1
new file mode 100644
index 0000000000000..7b19d32d872fa
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/okio-jvm-3.5.0.jar.sha1
@@ -0,0 +1 @@
+d6a0bc7343210eff7dd5cfdd6eb9b5f0036638ce
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/okio-jvm-LICENSE.txt b/plugins/telemetry-otel/licenses/okio-jvm-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/okio-jvm-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/okio-jvm-NOTICE.txt b/plugins/telemetry-otel/licenses/okio-jvm-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-api-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-api-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..b0ce00e191830
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-api-1.30.1.jar.sha1
@@ -0,0 +1 @@
+a32dfbd7f01de6711fd0e970f8d4b4c0405056d6
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-api-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-api-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-api-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-api-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-api-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-context-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-context-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..84cb60a2f7acb
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-context-1.30.1.jar.sha1
@@ -0,0 +1 @@
+58f665ff01ce6b964cdf0b8cb5cd1c196dfe94ce
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-context-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-context-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-context-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-context-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-context-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..eccb15f7b7c8e
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-1.30.1.jar.sha1
@@ -0,0 +1 @@
+f299d336dba1039478497f37b273dfa764c6faef
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-common-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..40537a399ab14
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-1.30.1.jar.sha1
@@ -0,0 +1 @@
+58f1a09e89955e6145babf8bcdf80c95174eb817
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-logging-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..e88b7514ee54d
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-1.30.1.jar.sha1
@@ -0,0 +1 @@
+15692246539571c41180aff2b55abe527b939a7b
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..86937743208c6
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-1.30.1.jar.sha1
@@ -0,0 +1 @@
+947cf43a6411c4a323e14594431040a476ad43e8
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-otlp-common-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..068926277253c
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-1.30.1.jar.sha1
@@ -0,0 +1 @@
+9f3a14515500e4df260ce7b10a668237a95ac791
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-LICENSE.txt
new file mode 100644
index 0000000000000..6b0b1270ff0ca
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-LICENSE.txt
@@ -0,0 +1,203 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-exporter-sender-okhttp-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-1.30.1-alpha.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-1.30.1-alpha.jar.sha1
new file mode 100644
index 0000000000000..bde43937e82e4
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-1.30.1-alpha.jar.sha1
@@ -0,0 +1 @@
+bfcea9bd71f97dd4e8a4f92c15ba5659fb07ff05
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-extension-incubator-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-sdk-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..d425ed61cc4cd
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-1.30.1.jar.sha1
@@ -0,0 +1 @@
+4d15a9ea26e8e6ea93287a9f4ee02d91e5a74392
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..6b32d98b0f7c7
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-1.30.1.jar.sha1
@@ -0,0 +1 @@
+8e437ba87004bb63069d04fb06beae65b98dd13a
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-common-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..13ef6de11e82d
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-1.30.1.jar.sha1
@@ -0,0 +1 @@
+5985d0950746ad12b49cc42c063f26ddfbcaaacb
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-logs-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..fc5aad9c9011e
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-1.30.1.jar.sha1
@@ -0,0 +1 @@
+b12825541c5dae52a0fb35045c1b36df3ca8f632
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-metrics-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-1.30.1.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-1.30.1.jar.sha1
new file mode 100644
index 0000000000000..ac522b765da05
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-1.30.1.jar.sha1
@@ -0,0 +1 @@
+4c5531fbc44178a7bcfeb7021ae80e70a7c43458
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-sdk-trace-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-semconv-1.30.1-alpha.jar.sha1 b/plugins/telemetry-otel/licenses/opentelemetry-semconv-1.30.1-alpha.jar.sha1
new file mode 100644
index 0000000000000..089a2484dd1d5
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-semconv-1.30.1-alpha.jar.sha1
@@ -0,0 +1 @@
+8e8f7a97a4896a81846553275b9d61885be7ef50
\ No newline at end of file
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-semconv-LICENSE.txt b/plugins/telemetry-otel/licenses/opentelemetry-semconv-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/plugins/telemetry-otel/licenses/opentelemetry-semconv-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
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+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
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+      communication on electronic mailing lists, source code control systems,
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+      designated in writing by the copyright owner as "Not a Contribution."
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+      "Contributor" shall mean Licensor and any individual or Legal Entity
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+   4. Redistribution. You may reproduce and distribute copies of the
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+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
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+
+      (c) You must retain, in the Source form of any Derivative Works
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+      (d) If the Work includes a "NOTICE" text file as part of its
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+          of the NOTICE file are for informational purposes only and
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+          notices within Derivative Works that You distribute, alongside
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+          that such additional attribution notices cannot be construed
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+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
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+      Work (including but not limited to damages for loss of goodwill,
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+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
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+      on Your own behalf and on Your sole responsibility, not on behalf
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+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
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+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/plugins/telemetry-otel/licenses/opentelemetry-semconv-NOTICE.txt b/plugins/telemetry-otel/licenses/opentelemetry-semconv-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/InMemorySingletonSpanExporter.java b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/InMemorySingletonSpanExporter.java
new file mode 100644
index 0000000000000..6dd451ea37465
--- /dev/null
+++ b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/InMemorySingletonSpanExporter.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.test.telemetry.tracing.MockSpanData;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.testing.exporter.InMemorySpanExporter;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+public class InMemorySingletonSpanExporter implements SpanExporter {
+
+    public static final InMemorySingletonSpanExporter INSTANCE = new InMemorySingletonSpanExporter(InMemorySpanExporter.create());
+
+    private static InMemorySpanExporter delegate;
+
+    public static InMemorySingletonSpanExporter create() {
+        return INSTANCE;
+    }
+
+    private InMemorySingletonSpanExporter(InMemorySpanExporter delegate) {
+        InMemorySingletonSpanExporter.delegate = delegate;
+    }
+
+    @Override
+    public CompletableResultCode export(Collection<SpanData> spans) {
+        return delegate.export(spans);
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+        return delegate.flush();
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+        return delegate.shutdown();
+    }
+
+    public List<MockSpanData> getFinishedSpanItems() {
+        return convertSpanDataListToMockSpanDataList(delegate.getFinishedSpanItems());
+    }
+
+    private List<MockSpanData> convertSpanDataListToMockSpanDataList(List<SpanData> spanDataList) {
+        List<MockSpanData> mockSpanDataList = spanDataList.stream()
+            .map(
+                spanData -> new MockSpanData(
+                    spanData.getSpanId(),
+                    spanData.getParentSpanId(),
+                    spanData.getTraceId(),
+                    spanData.getStartEpochNanos(),
+                    spanData.getEndEpochNanos(),
+                    spanData.hasEnded(),
+                    spanData.getName(),
+                    getAttributes(spanData)
+                )
+            )
+            .collect(Collectors.toList());
+        return mockSpanDataList;
+    }
+
+    private Map<String, Object> getAttributes(SpanData spanData) {
+        if (spanData.getAttributes() != null) {
+            return spanData.getAttributes()
+                .asMap()
+                .entrySet()
+                .stream()
+                .collect(Collectors.toMap(e -> e.getKey().getKey(), e -> e.getValue()));
+        } else {
+            return Collections.emptyMap();
+        }
+    }
+
+    /**
+     * Clears the state.
+     */
+    public void reset() {
+        delegate.reset();
+    }
+}
diff --git a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java
new file mode 100644
index 0000000000000..ed4d13f3abb7d
--- /dev/null
+++ b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.OTelTelemetryPlugin;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+
+import java.util.Optional;
+
+import io.opentelemetry.api.GlobalOpenTelemetry;
+
+/**
+ * Telemetry plugin used for Integration tests.
+*/
+public class IntegrationTestOTelTelemetryPlugin extends OTelTelemetryPlugin {
+    /**
+     * Creates IntegrationTestOTelTelemetryPlugin
+     * @param settings cluster settings
+     */
+    public IntegrationTestOTelTelemetryPlugin(Settings settings) {
+        super(settings);
+    }
+
+    /**
+     * This method overrides getTelemetry() method in OTel plugin class, so we create only one instance of global OpenTelemetry
+     * resetForTest() will set OpenTelemetry to null again.
+     * @param telemetrySettings telemetry settings
+     */
+    public Optional<Telemetry> getTelemetry(TelemetrySettings telemetrySettings) {
+        GlobalOpenTelemetry.resetForTest();
+        return super.getTelemetry(telemetrySettings);
+    }
+}
diff --git a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerDisabledSanityIT.java b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerDisabledSanityIT.java
new file mode 100644
index 0000000000000..949a58f6cab41
--- /dev/null
+++ b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerDisabledSanityIT.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, supportsDedicatedMasters = false, minNumDataNodes = 2)
+public class TelemetryTracerDisabledSanityIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(
+                OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(),
+                "org.opensearch.telemetry.tracing.InMemorySingletonSpanExporter"
+            )
+            .put(OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING.getKey(), TimeValue.timeValueSeconds(1))
+            .build();
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(IntegrationTestOTelTelemetryPlugin.class);
+    }
+
+    @Override
+    protected boolean addMockTelemetryPlugin() {
+        return false;
+    }
+
+    public void testSanityCheckWhenTracingDisabled() throws Exception {
+        Client client = client();
+        // DISABLE TRACING
+        client.admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), false))
+            .get();
+
+        // Create Index and ingest data
+        String indexName = "test-index-11";
+        Settings basicSettings = Settings.builder().put("number_of_shards", 3).put("number_of_replicas", 1).build();
+        createIndex(indexName, basicSettings);
+        indexRandom(true, client.prepareIndex(indexName).setId("1").setSource("field1", "t`"));
+
+        ensureGreen();
+        refresh();
+        InMemorySingletonSpanExporter exporter = InMemorySingletonSpanExporter.INSTANCE;
+        exporter.reset();
+
+        // Make the search call;
+        client.prepareSearch().setQuery(queryStringQuery("fox")).get();
+
+        // Sleep for about 3s to wait for traces are published (the delay is 1s)
+        Thread.sleep(3000);
+
+        assertTrue(exporter.getFinishedSpanItems().isEmpty());
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerEnabledSanityIT.java b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerEnabledSanityIT.java
new file mode 100644
index 0000000000000..8a49a0abf5512
--- /dev/null
+++ b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/TelemetryTracerEnabledSanityIT.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.telemetry.tracing.TelemetryValidators;
+import org.opensearch.test.telemetry.tracing.validators.AllSpansAreEndedProperly;
+import org.opensearch.test.telemetry.tracing.validators.AllSpansHaveUniqueId;
+import org.opensearch.test.telemetry.tracing.validators.NumberOfTraceIDsEqualToRequests;
+import org.opensearch.test.telemetry.tracing.validators.TotalRootSpansEqualToRequests;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, minNumDataNodes = 2)
+public class TelemetryTracerEnabledSanityIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(
+                OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(),
+                "org.opensearch.telemetry.tracing.InMemorySingletonSpanExporter"
+            )
+            .put(OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING.getKey(), TimeValue.timeValueSeconds(1))
+            .put(TelemetrySettings.TRACER_SAMPLER_PROBABILITY.getKey(), 1.0d)
+            .build();
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(IntegrationTestOTelTelemetryPlugin.class);
+    }
+
+    @Override
+    protected boolean addMockTelemetryPlugin() {
+        return false;
+    }
+
+    public void testSanityChecksWhenTracingEnabled() throws Exception {
+        Client client = internalCluster().clusterManagerClient();
+        // ENABLE TRACING
+        updateTelemetrySetting(client, true);
+
+        // Create Index and ingest data
+        String indexName = "test-index-11";
+        Settings basicSettings = Settings.builder().put("number_of_shards", 3).put("number_of_replicas", 0).build();
+        createIndex(indexName, basicSettings);
+        indexRandom(true, client.prepareIndex(indexName).setId("1").setSource("field1", "the fox jumps in the well"));
+        indexRandom(true, client.prepareIndex(indexName).setId("1").setSource("field2", "another fox did the same."));
+
+        ensureGreen();
+        refresh();
+
+        // Make the search calls; adding the searchType and PreFilterShardSize to make the query path predictable across all the runs.
+        client.prepareSearch().setSearchType("query_then_fetch").setPreFilterShardSize(3).setQuery(queryStringQuery("fox")).get();
+        client.prepareSearch().setSearchType("query_then_fetch").setPreFilterShardSize(3).setQuery(queryStringQuery("jumps")).get();
+
+        ensureGreen();
+        refresh();
+
+        // Sleep for about 3s to wait for traces are published, delay is (the delay is 1s).
+        Thread.sleep(3000);
+
+        TelemetryValidators validators = new TelemetryValidators(
+            Arrays.asList(
+                new AllSpansAreEndedProperly(),
+                new AllSpansHaveUniqueId(),
+                new NumberOfTraceIDsEqualToRequests(Attributes.create().addAttribute("action", "indices:data/read/search[phase/query]")),
+                new TotalRootSpansEqualToRequests()
+            )
+        );
+
+        InMemorySingletonSpanExporter exporter = InMemorySingletonSpanExporter.INSTANCE;
+        if (!exporter.getFinishedSpanItems().isEmpty()) {
+            validators.validate(exporter.getFinishedSpanItems(), 6);
+        }
+    }
+
+    private static void updateTelemetrySetting(Client client, boolean value) {
+        client.admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), value))
+            .get();
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelAttributesConverter.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelAttributesConverter.java
new file mode 100644
index 0000000000000..98d265e92ba3c
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelAttributesConverter.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.telemetry.metrics.tags.Tags;
+
+import java.util.Locale;
+
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.common.AttributesBuilder;
+
+/**
+ * Converts {@link org.opensearch.telemetry.tracing.attributes.Attributes} to OTel {@link Attributes}
+ */
+public final class OTelAttributesConverter {
+
+    /**
+     * Constructor.
+     */
+    private OTelAttributesConverter() {}
+
+    /**
+     * Attribute converter.
+     * @param attributes attributes
+     * @return otel attributes.
+     */
+    public static Attributes convert(org.opensearch.telemetry.tracing.attributes.Attributes attributes) {
+        AttributesBuilder attributesBuilder = Attributes.builder();
+        if (attributes != null) {
+            attributes.getAttributesMap().forEach((x, y) -> addSpanAttribute(x, y, attributesBuilder));
+        }
+        return attributesBuilder.build();
+    }
+
+    private static void addSpanAttribute(String key, Object value, AttributesBuilder attributesBuilder) {
+        if (value instanceof Boolean) {
+            attributesBuilder.put(key, (Boolean) value);
+        } else if (value instanceof Long) {
+            attributesBuilder.put(key, (Long) value);
+        } else if (value instanceof Double) {
+            attributesBuilder.put(key, (Double) value);
+        } else if (value instanceof String) {
+            attributesBuilder.put(key, (String) value);
+        } else {
+            throw new IllegalArgumentException(String.format(Locale.ROOT, "Span attribute value %s type not supported", value));
+        }
+    }
+
+    /**
+     * Attribute converter.
+     * @param tags attributes
+     * @return otel attributes.
+     */
+    public static Attributes convert(Tags tags) {
+        AttributesBuilder attributesBuilder = Attributes.builder();
+        if (tags != null) {
+            tags.getTagsMap().forEach((x, y) -> addSpanAttribute(x, y, attributesBuilder));
+        }
+        return attributesBuilder.build();
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java
new file mode 100644
index 0000000000000..b57876c9310f3
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.TelemetryPlugin;
+import org.opensearch.telemetry.metrics.OTelMetricsTelemetry;
+import org.opensearch.telemetry.tracing.OTelResourceProvider;
+import org.opensearch.telemetry.tracing.OTelTelemetry;
+import org.opensearch.telemetry.tracing.OTelTracingTelemetry;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+
+import io.opentelemetry.sdk.OpenTelemetrySdk;
+
+/**
+ * Telemetry plugin based on Otel
+ */
+public class OTelTelemetryPlugin extends Plugin implements TelemetryPlugin {
+
+    /**
+     * Instrumentation scope name.
+     */
+    public static final String INSTRUMENTATION_SCOPE_NAME = "org.opensearch.telemetry";
+
+    static final String OTEL_TRACER_NAME = "otel";
+
+    private final Settings settings;
+
+    /**
+     * Creates Otel plugin
+     * @param settings cluster settings
+     */
+    public OTelTelemetryPlugin(Settings settings) {
+        this.settings = settings;
+    }
+
+    @Override
+    public List<Setting<?>> getSettings() {
+        return Arrays.asList(
+            OTelTelemetrySettings.TRACER_EXPORTER_BATCH_SIZE_SETTING,
+            OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING,
+            OTelTelemetrySettings.TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING,
+            OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING,
+            OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING
+        );
+    }
+
+    @Override
+    public Optional<Telemetry> getTelemetry(TelemetrySettings telemetrySettings) {
+        return Optional.of(telemetry(telemetrySettings));
+    }
+
+    @Override
+    public String getName() {
+        return OTEL_TRACER_NAME;
+    }
+
+    private Telemetry telemetry(TelemetrySettings telemetrySettings) {
+        final OpenTelemetrySdk openTelemetry = OTelResourceProvider.get(telemetrySettings, settings);
+        return new OTelTelemetry(
+            new OTelTracingTelemetry<>(openTelemetry, openTelemetry.getSdkTracerProvider()),
+            new OTelMetricsTelemetry<>(openTelemetry.getSdkMeterProvider())
+        );
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetrySettings.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetrySettings.java
new file mode 100644
index 0000000000000..8e23f724b4570
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetrySettings.java
@@ -0,0 +1,113 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.SpecialPermission;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.telemetry.metrics.exporter.OTelMetricsExporterFactory;
+import org.opensearch.telemetry.tracing.exporter.OTelSpanExporterFactory;
+
+import java.security.AccessController;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+
+import io.opentelemetry.exporter.logging.LoggingMetricExporter;
+import io.opentelemetry.exporter.logging.LoggingSpanExporter;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+/**
+ * OTel specific telemetry settings.
+ */
+public final class OTelTelemetrySettings {
+
+    /**
+     * Base Constructor.
+     */
+    private OTelTelemetrySettings() {}
+
+    /**
+     * span exporter batch size
+     */
+    public static final Setting<Integer> TRACER_EXPORTER_BATCH_SIZE_SETTING = Setting.intSetting(
+        "telemetry.otel.tracer.exporter.batch_size",
+        512,
+        1,
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+    /**
+     * span exporter max queue size
+     */
+    public static final Setting<Integer> TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING = Setting.intSetting(
+        "telemetry.otel.tracer.exporter.max_queue_size",
+        2048,
+        1,
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+    /**
+     * span exporter delay in seconds
+     */
+    public static final Setting<TimeValue> TRACER_EXPORTER_DELAY_SETTING = Setting.timeSetting(
+        "telemetry.otel.tracer.exporter.delay",
+        TimeValue.timeValueSeconds(2),
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+
+    /**
+     * Span Exporter type setting.
+     */
+    @SuppressWarnings("unchecked")
+    public static final Setting<Class<SpanExporter>> OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING = new Setting<>(
+        "telemetry.otel.tracer.span.exporter.class",
+        LoggingSpanExporter.class.getName(),
+        className -> {
+            // Check we ourselves are not being called by unprivileged code.
+            SpecialPermission.check();
+
+            try {
+                return AccessController.doPrivileged((PrivilegedExceptionAction<Class<SpanExporter>>) () -> {
+                    final ClassLoader loader = OTelSpanExporterFactory.class.getClassLoader();
+                    return (Class<SpanExporter>) loader.loadClass(className);
+                });
+            } catch (PrivilegedActionException ex) {
+                throw new IllegalStateException("Unable to load span exporter class:" + className, ex.getCause());
+            }
+        },
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+
+    /**
+     * Metrics Exporter type setting.
+     */
+    @SuppressWarnings("unchecked")
+    public static final Setting<Class<MetricExporter>> OTEL_METRICS_EXPORTER_CLASS_SETTING = new Setting<>(
+        "telemetry.otel.metrics.exporter.class",
+        LoggingMetricExporter.class.getName(),
+        className -> {
+            // Check we ourselves are not being called by unprivileged code.
+            SpecialPermission.check();
+
+            try {
+                return AccessController.doPrivileged((PrivilegedExceptionAction<Class<MetricExporter>>) () -> {
+                    final ClassLoader loader = OTelMetricsExporterFactory.class.getClassLoader();
+                    return (Class<MetricExporter>) loader.loadClass(className);
+                });
+            } catch (PrivilegedActionException ex) {
+                throw new IllegalStateException("Unable to load span exporter class:" + className, ex.getCause());
+            }
+        },
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelCounter.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelCounter.java
new file mode 100644
index 0000000000000..b72f63e027243
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelCounter.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.telemetry.OTelAttributesConverter;
+import org.opensearch.telemetry.metrics.tags.Tags;
+
+import io.opentelemetry.api.metrics.DoubleCounter;
+
+/**
+ * OTel Counter
+ */
+class OTelCounter implements Counter {
+
+    private final DoubleCounter otelDoubleCounter;
+
+    /**
+     * Constructor
+     * @param otelDoubleCounter delegate counter.
+     */
+    public OTelCounter(DoubleCounter otelDoubleCounter) {
+        this.otelDoubleCounter = otelDoubleCounter;
+    }
+
+    @Override
+    public void add(double value) {
+        otelDoubleCounter.add(value);
+    }
+
+    @Override
+    public void add(double value, Tags tags) {
+        otelDoubleCounter.add(value, OTelAttributesConverter.convert(tags));
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetry.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetry.java
new file mode 100644
index 0000000000000..8598e5976d20d
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetry.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.telemetry.OTelTelemetryPlugin;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+import io.opentelemetry.api.metrics.DoubleCounter;
+import io.opentelemetry.api.metrics.DoubleUpDownCounter;
+import io.opentelemetry.api.metrics.Meter;
+import io.opentelemetry.api.metrics.MeterProvider;
+
+/**
+ * OTel implementation for {@link MetricsTelemetry}
+ */
+public class OTelMetricsTelemetry<T extends MeterProvider & Closeable> implements MetricsTelemetry {
+    private final Meter otelMeter;
+    private final T meterProvider;
+
+    /**
+     * Creates OTel based {@link MetricsTelemetry}.
+     * @param meterProvider {@link MeterProvider} instance
+     */
+    public OTelMetricsTelemetry(T meterProvider) {
+        this.meterProvider = meterProvider;
+        this.otelMeter = meterProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME);
+    }
+
+    @Override
+    public Counter createCounter(String name, String description, String unit) {
+        DoubleCounter doubleCounter = AccessController.doPrivileged(
+            (PrivilegedAction<DoubleCounter>) () -> otelMeter.counterBuilder(name)
+                .setUnit(unit)
+                .setDescription(description)
+                .ofDoubles()
+                .build()
+        );
+        return new OTelCounter(doubleCounter);
+    }
+
+    @Override
+    public Counter createUpDownCounter(String name, String description, String unit) {
+        DoubleUpDownCounter doubleUpDownCounter = AccessController.doPrivileged(
+            (PrivilegedAction<DoubleUpDownCounter>) () -> otelMeter.upDownCounterBuilder(name)
+                .setUnit(unit)
+                .setDescription(description)
+                .ofDoubles()
+                .build()
+        );
+        return new OTelUpDownCounter(doubleUpDownCounter);
+    }
+
+    @Override
+    public void close() throws IOException {
+        meterProvider.close();
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelUpDownCounter.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelUpDownCounter.java
new file mode 100644
index 0000000000000..2f40881996f7e
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/OTelUpDownCounter.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.telemetry.OTelAttributesConverter;
+import org.opensearch.telemetry.metrics.tags.Tags;
+
+import io.opentelemetry.api.metrics.DoubleUpDownCounter;
+
+/**
+ * OTel Counter
+ */
+public class OTelUpDownCounter implements Counter {
+
+    private final DoubleUpDownCounter doubleUpDownCounter;
+
+    /**
+     * Constructor
+     * @param doubleUpDownCounter delegate counter.
+     */
+    public OTelUpDownCounter(DoubleUpDownCounter doubleUpDownCounter) {
+        this.doubleUpDownCounter = doubleUpDownCounter;
+    }
+
+    @Override
+    public void add(double value) {
+        doubleUpDownCounter.add(value);
+    }
+
+    @Override
+    public void add(double value, Tags tags) {
+        doubleUpDownCounter.add(value, OTelAttributesConverter.convert(tags));
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactory.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactory.java
new file mode 100644
index 0000000000000..ef5a31e4003ca
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactory.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.exporter;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.SpecialPermission;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.Method;
+import java.security.AccessController;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+
+/**
+ * Factory class to create the {@link MetricExporter} instance.
+ */
+public class OTelMetricsExporterFactory {
+
+    private static final Logger logger = LogManager.getLogger(OTelMetricsExporterFactory.class);
+
+    /**
+     * Base constructor.
+     */
+    private OTelMetricsExporterFactory() {
+
+    }
+
+    /**
+     * Creates the {@link MetricExporter} instances based on the OTEL_METRIC_EXPORTER_CLASS_SETTING value.
+     * As of now, it expects the MetricExporter implementations to have a create factory method to instantiate the
+     * MetricExporter.
+     * @param settings settings.
+     * @return MetricExporter instance.
+     */
+    public static MetricExporter create(Settings settings) {
+        Class<MetricExporter> MetricExporterProviderClass = OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.get(settings);
+        MetricExporter metricExporter = instantiateExporter(MetricExporterProviderClass);
+        logger.info("Successfully instantiated the Metrics MetricExporter class {}", MetricExporterProviderClass);
+        return metricExporter;
+    }
+
+    private static MetricExporter instantiateExporter(Class<MetricExporter> exporterProviderClass) {
+        try {
+            // Check we ourselves are not being called by unprivileged code.
+            SpecialPermission.check();
+            return AccessController.doPrivileged((PrivilegedExceptionAction<MetricExporter>) () -> {
+                String methodName = "create";
+                String getDefaultMethod = "getDefault";
+                for (Method m : exporterProviderClass.getMethods()) {
+                    if (m.getName().equals(getDefaultMethod)) {
+                        methodName = getDefaultMethod;
+                        break;
+                    }
+                }
+                try {
+                    return (MetricExporter) MethodHandles.publicLookup()
+                        .findStatic(exporterProviderClass, methodName, MethodType.methodType(exporterProviderClass))
+                        .asType(MethodType.methodType(MetricExporter.class))
+                        .invokeExact();
+                } catch (Throwable e) {
+                    if (e.getCause() instanceof NoSuchMethodException) {
+                        throw new IllegalStateException("No create factory method exist in [" + exporterProviderClass.getName() + "]");
+                    } else {
+                        throw new IllegalStateException(
+                            "MetricExporter instantiation failed for class [" + exporterProviderClass.getName() + "]",
+                            e.getCause()
+                        );
+                    }
+                }
+            });
+        } catch (PrivilegedActionException ex) {
+            throw new IllegalStateException(
+                "MetricExporter instantiation failed for class [" + exporterProviderClass.getName() + "]",
+                ex.getCause()
+            );
+        }
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/package-info.java
new file mode 100644
index 0000000000000..b48ec3e2336c4
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/exporter/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.metrics.exporter;
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/package-info.java
new file mode 100644
index 0000000000000..803c159eb201a
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/metrics/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.metrics;
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/package-info.java
new file mode 100644
index 0000000000000..4545f0ef5990e
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for telemetry.
+ */
+package org.opensearch.telemetry;
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelPropagatedSpan.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelPropagatedSpan.java
new file mode 100644
index 0000000000000..5aa1069e60367
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelPropagatedSpan.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+/**
+ * Propagated span through context propagation
+ */
+public class OTelPropagatedSpan extends OTelSpan {
+
+    /**
+     * Creates OTelPropagatedSpan
+     * @param span otel propagated span
+     */
+    public OTelPropagatedSpan(io.opentelemetry.api.trace.Span span) {
+        super(null, span, null);
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java
new file mode 100644
index 0000000000000..a6a1f12aab8a9
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.metrics.exporter.OTelMetricsExporterFactory;
+import org.opensearch.telemetry.tracing.exporter.OTelSpanExporterFactory;
+import org.opensearch.telemetry.tracing.sampler.ProbabilisticSampler;
+import org.opensearch.telemetry.tracing.sampler.RequestSampler;
+
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.concurrent.TimeUnit;
+
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.propagation.W3CTraceContextPropagator;
+import io.opentelemetry.context.propagation.ContextPropagators;
+import io.opentelemetry.sdk.OpenTelemetrySdk;
+import io.opentelemetry.sdk.metrics.SdkMeterProvider;
+import io.opentelemetry.sdk.metrics.export.PeriodicMetricReader;
+import io.opentelemetry.sdk.resources.Resource;
+import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import io.opentelemetry.sdk.trace.export.BatchSpanProcessor;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+import io.opentelemetry.semconv.resource.attributes.ResourceAttributes;
+
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_BATCH_SIZE_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING;
+
+/**
+ * This class encapsulates all OpenTelemetry related resources
+ */
+public final class OTelResourceProvider {
+    private OTelResourceProvider() {}
+
+    /**
+     * Creates OpenTelemetry instance with default configuration
+     * @param telemetrySettings telemetry settings
+     * @param settings cluster settings
+     * @return OpenTelemetrySdk instance
+     */
+    public static OpenTelemetrySdk get(TelemetrySettings telemetrySettings, Settings settings) {
+        return AccessController.doPrivileged(
+            (PrivilegedAction<OpenTelemetrySdk>) () -> get(
+                settings,
+                OTelSpanExporterFactory.create(settings),
+                ContextPropagators.create(W3CTraceContextPropagator.getInstance()),
+                Sampler.parentBased(new RequestSampler(new ProbabilisticSampler(telemetrySettings)))
+            )
+        );
+    }
+
+    /**
+     * Creates OpenTelemetry instance with provided configuration
+     * @param settings cluster settings
+     * @param spanExporter span exporter instance
+     * @param contextPropagators context propagator instance
+     * @param sampler sampler instance
+     * @return OpenTelemetrySdk instance
+     */
+    public static OpenTelemetrySdk get(
+        Settings settings,
+        SpanExporter spanExporter,
+        ContextPropagators contextPropagators,
+        Sampler sampler
+    ) {
+        Resource resource = Resource.create(Attributes.of(ResourceAttributes.SERVICE_NAME, "OpenSearch"));
+        SdkTracerProvider sdkTracerProvider = createSdkTracerProvider(settings, spanExporter, sampler, resource);
+        SdkMeterProvider sdkMeterProvider = createSdkMetricProvider(settings, resource);
+        return OpenTelemetrySdk.builder()
+            .setTracerProvider(sdkTracerProvider)
+            .setMeterProvider(sdkMeterProvider)
+            .setPropagators(contextPropagators)
+            .buildAndRegisterGlobal();
+    }
+
+    private static SdkMeterProvider createSdkMetricProvider(Settings settings, Resource resource) {
+        return SdkMeterProvider.builder()
+            .setResource(resource)
+            .registerMetricReader(
+                PeriodicMetricReader.builder(OTelMetricsExporterFactory.create(settings))
+                    .setInterval(TelemetrySettings.METRICS_PUBLISH_INTERVAL_SETTING.get(settings).getSeconds(), TimeUnit.SECONDS)
+                    .build()
+            )
+            .build();
+    }
+
+    private static SdkTracerProvider createSdkTracerProvider(
+        Settings settings,
+        SpanExporter spanExporter,
+        Sampler sampler,
+        Resource resource
+    ) {
+        return SdkTracerProvider.builder()
+            .addSpanProcessor(spanProcessor(settings, spanExporter))
+            .setResource(resource)
+            .setSampler(sampler)
+            .build();
+    }
+
+    private static BatchSpanProcessor spanProcessor(Settings settings, SpanExporter spanExporter) {
+        return BatchSpanProcessor.builder(spanExporter)
+            .setScheduleDelay(TRACER_EXPORTER_DELAY_SETTING.get(settings).getSeconds(), TimeUnit.SECONDS)
+            .setMaxExportBatchSize(TRACER_EXPORTER_BATCH_SIZE_SETTING.get(settings))
+            .setMaxQueueSize(TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING.get(settings))
+            .build();
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpan.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpan.java
new file mode 100644
index 0000000000000..fc917968579e1
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpan.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.StatusCode;
+
+/**
+ * Default implementation of {@link Span} using Otel span. It keeps a reference of OpenTelemetry Span and handles span
+ * lifecycle management by delegating calls to it.
+ */
+class OTelSpan extends AbstractSpan {
+
+    private final Span delegateSpan;
+
+    /**
+     * Constructor
+     * @param spanName span name
+     * @param span the delegate span
+     * @param parentSpan the parent span
+     */
+    public OTelSpan(String spanName, Span span, org.opensearch.telemetry.tracing.Span parentSpan) {
+        super(spanName, parentSpan);
+        this.delegateSpan = span;
+    }
+
+    @Override
+    public void endSpan() {
+        delegateSpan.end();
+    }
+
+    @Override
+    public void addAttribute(String key, String value) {
+        delegateSpan.setAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Long value) {
+        delegateSpan.setAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Double value) {
+        delegateSpan.setAttribute(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Boolean value) {
+        delegateSpan.setAttribute(key, value);
+    }
+
+    @Override
+    public void setError(Exception exception) {
+        if (exception != null) {
+            delegateSpan.setStatus(StatusCode.ERROR, exception.getMessage());
+        }
+    }
+
+    @Override
+    public void addEvent(String event) {
+        delegateSpan.addEvent(event);
+    }
+
+    @Override
+    public String getTraceId() {
+        return delegateSpan.getSpanContext().getTraceId();
+    }
+
+    @Override
+    public String getSpanId() {
+        return delegateSpan.getSpanContext().getSpanId();
+    }
+
+    io.opentelemetry.api.trace.Span getDelegateSpan() {
+        return delegateSpan;
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpanKindConverter.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpanKindConverter.java
new file mode 100644
index 0000000000000..4edb837082126
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelSpanKindConverter.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import io.opentelemetry.api.trace.SpanKind;
+
+/**
+ * Converts {@link org.opensearch.telemetry.tracing.SpanKind} to OTel {@link SpanKind}
+ */
+final class OTelSpanKindConverter {
+
+    /**
+     * Constructor.
+     */
+    private OTelSpanKindConverter() {}
+
+    /**
+     * SpanKind converter.
+     * @param spanKind span kind.
+     * @return otel attributes.
+     */
+    static SpanKind convert(org.opensearch.telemetry.tracing.SpanKind spanKind) {
+        if (spanKind == null) {
+            return SpanKind.INTERNAL;
+        } else {
+            switch (spanKind) {
+                case CLIENT:
+                    return SpanKind.CLIENT;
+                case SERVER:
+                    return SpanKind.SERVER;
+                case INTERNAL:
+                default:
+                    return SpanKind.INTERNAL;
+            }
+        }
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTelemetry.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTelemetry.java
new file mode 100644
index 0000000000000..282fabd43346b
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTelemetry.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.metrics.MetricsTelemetry;
+
+/**
+ * Otel implementation of Telemetry
+ */
+public class OTelTelemetry implements Telemetry {
+
+    private final TracingTelemetry tracingTelemetry;
+    private final MetricsTelemetry metricsTelemetry;
+
+    /**
+     * Creates Telemetry instance
+     * @param tracingTelemetry tracing telemetry
+     * @param metricsTelemetry metrics telemetry
+     */
+    public OTelTelemetry(TracingTelemetry tracingTelemetry, MetricsTelemetry metricsTelemetry) {
+        this.tracingTelemetry = tracingTelemetry;
+        this.metricsTelemetry = metricsTelemetry;
+    }
+
+    @Override
+    public TracingTelemetry getTracingTelemetry() {
+        return tracingTelemetry;
+    }
+
+    @Override
+    public MetricsTelemetry getMetricsTelemetry() {
+        return metricsTelemetry;
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagator.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagator.java
new file mode 100644
index 0000000000000..f8fe885ee450c
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagator.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.core.common.Strings;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.BiConsumer;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.propagation.TextMapGetter;
+import io.opentelemetry.context.propagation.TextMapSetter;
+
+/**
+ * Otel implementation of TracingContextPropagator
+ */
+public class OTelTracingContextPropagator implements TracingContextPropagator {
+
+    private final OpenTelemetry openTelemetry;
+
+    /**
+     * Creates OTelTracingContextPropagator instance
+     * @param openTelemetry Otel OpenTelemetry instance
+     */
+    public OTelTracingContextPropagator(OpenTelemetry openTelemetry) {
+        this.openTelemetry = openTelemetry;
+    }
+
+    @Override
+    public Optional<Span> extract(Map<String, String> props) {
+        Context context = openTelemetry.getPropagators().getTextMapPropagator().extract(Context.current(), props, TEXT_MAP_GETTER);
+        return Optional.ofNullable(getPropagatedSpan(context));
+    }
+
+    private static OTelPropagatedSpan getPropagatedSpan(Context context) {
+        if (context != null) {
+            io.opentelemetry.api.trace.Span span = io.opentelemetry.api.trace.Span.fromContext(context);
+            return new OTelPropagatedSpan(span);
+        }
+        return null;
+    }
+
+    @Override
+    public Optional<Span> extractFromHeaders(Map<String, List<String>> headers) {
+        Context context = openTelemetry.getPropagators().getTextMapPropagator().extract(Context.current(), headers, HEADER_TEXT_MAP_GETTER);
+        return Optional.ofNullable(getPropagatedSpan(context));
+    }
+
+    @Override
+    public void inject(Span currentSpan, BiConsumer<String, String> setter) {
+        openTelemetry.getPropagators().getTextMapPropagator().inject(context((OTelSpan) currentSpan), setter, TEXT_MAP_SETTER);
+
+    }
+
+    private static Context context(OTelSpan oTelSpan) {
+        return Context.current().with(io.opentelemetry.api.trace.Span.wrap(oTelSpan.getDelegateSpan().getSpanContext()));
+    }
+
+    private static final TextMapSetter<BiConsumer<String, String>> TEXT_MAP_SETTER = (carrier, key, value) -> {
+        if (carrier != null) {
+            carrier.accept(key, value);
+        }
+    };
+
+    private static final TextMapGetter<Map<String, String>> TEXT_MAP_GETTER = new TextMapGetter<>() {
+        @Override
+        public Iterable<String> keys(Map<String, String> headers) {
+            return headers.keySet();
+        }
+
+        @Override
+        public String get(Map<String, String> headers, String key) {
+            if (headers != null && headers.containsKey(key)) {
+                return headers.get(key);
+            }
+            return null;
+        }
+    };
+
+    private static final TextMapGetter<Map<String, List<String>>> HEADER_TEXT_MAP_GETTER = new TextMapGetter<>() {
+        @Override
+        public Iterable<String> keys(Map<String, List<String>> headers) {
+            if (headers != null) {
+                return headers.keySet();
+            } else {
+                return Collections.emptySet();
+            }
+        }
+
+        @Override
+        public String get(Map<String, List<String>> headers, String key) {
+            if (headers != null && headers.containsKey(key)) {
+                return Strings.collectionToCommaDelimitedString(headers.get(key));
+            }
+            return null;
+        }
+    };
+
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingTelemetry.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingTelemetry.java
new file mode 100644
index 0000000000000..f88afe623fd56
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelTracingTelemetry.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.telemetry.OTelAttributesConverter;
+import org.opensearch.telemetry.OTelTelemetryPlugin;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.api.trace.TracerProvider;
+import io.opentelemetry.context.Context;
+
+/**
+ * OTel based Telemetry provider
+ */
+public class OTelTracingTelemetry<T extends TracerProvider & Closeable> implements TracingTelemetry {
+    private final OpenTelemetry openTelemetry;
+    private final T tracerProvider;
+    private final io.opentelemetry.api.trace.Tracer otelTracer;
+
+    /**
+     * Creates OTel based {@link TracingTelemetry}
+     * @param openTelemetry OpenTelemetry instance
+     * @param tracerProvider {@link TracerProvider} instance.
+     */
+    public OTelTracingTelemetry(OpenTelemetry openTelemetry, T tracerProvider) {
+        this.openTelemetry = openTelemetry;
+        this.tracerProvider = tracerProvider;
+        this.otelTracer = tracerProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME);
+    }
+
+    @Override
+    public void close() throws IOException {
+        tracerProvider.close();
+    }
+
+    @Override
+    public Span createSpan(SpanCreationContext spanCreationContext, Span parentSpan) {
+        return createOtelSpan(spanCreationContext, parentSpan);
+    }
+
+    @Override
+    public TracingContextPropagator getContextPropagator() {
+        return new OTelTracingContextPropagator(openTelemetry);
+    }
+
+    private Span createOtelSpan(SpanCreationContext spanCreationContext, Span parentSpan) {
+        io.opentelemetry.api.trace.Span otelSpan = otelSpan(
+            spanCreationContext.getSpanName(),
+            parentSpan,
+            OTelAttributesConverter.convert(spanCreationContext.getAttributes()),
+            OTelSpanKindConverter.convert(spanCreationContext.getSpanKind())
+        );
+        Span newSpan = new OTelSpan(spanCreationContext.getSpanName(), otelSpan, parentSpan);
+        return newSpan;
+    }
+
+    io.opentelemetry.api.trace.Span otelSpan(
+        String spanName,
+        Span parentOTelSpan,
+        io.opentelemetry.api.common.Attributes attributes,
+        io.opentelemetry.api.trace.SpanKind spanKind
+    ) {
+        return parentOTelSpan == null || !(parentOTelSpan instanceof OTelSpan)
+            ? otelTracer.spanBuilder(spanName).setAllAttributes(attributes).startSpan()
+            : otelTracer.spanBuilder(spanName)
+                .setParent(Context.current().with(((OTelSpan) parentOTelSpan).getDelegateSpan()))
+                .setAllAttributes(attributes)
+                .setSpanKind(spanKind)
+                .startSpan();
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactory.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactory.java
new file mode 100644
index 0000000000000..da7ce5c47d9ca
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactory.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.exporter;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.SpecialPermission;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.Method;
+import java.security.AccessController;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+/**
+ * Factory class to create the {@link SpanExporter} instance.
+ */
+public class OTelSpanExporterFactory {
+
+    private static final Logger logger = LogManager.getLogger(OTelSpanExporterFactory.class);
+
+    /**
+     * Base constructor.
+     */
+    private OTelSpanExporterFactory() {
+
+    }
+
+    /**
+     * Creates the {@link SpanExporter} instances based on the OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING value.
+     * As of now, it expects the SpanExporter implementations to have a create factory method to instantiate the
+     * SpanExporter.
+     * @param settings settings.
+     * @return SpanExporter instance.
+     */
+    public static SpanExporter create(Settings settings) {
+        Class<SpanExporter> spanExporterProviderClass = OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.get(settings);
+        SpanExporter spanExporter = instantiateSpanExporter(spanExporterProviderClass);
+        logger.info("Successfully instantiated the SpanExporter class {}", spanExporterProviderClass);
+        return spanExporter;
+    }
+
+    private static SpanExporter instantiateSpanExporter(Class<SpanExporter> spanExporterProviderClass) {
+        try {
+            // Check we ourselves are not being called by unprivileged code.
+            SpecialPermission.check();
+            return AccessController.doPrivileged((PrivilegedExceptionAction<SpanExporter>) () -> {
+                String methodName = "create";
+                String getDefaultMethod = "getDefault";
+                for (Method m : spanExporterProviderClass.getMethods()) {
+                    if (m.getName().equals(getDefaultMethod)) {
+                        methodName = getDefaultMethod;
+                        break;
+                    }
+                }
+                try {
+                    return (SpanExporter) MethodHandles.publicLookup()
+                        .findStatic(spanExporterProviderClass, methodName, MethodType.methodType(spanExporterProviderClass))
+                        .asType(MethodType.methodType(SpanExporter.class))
+                        .invokeExact();
+                } catch (Throwable e) {
+                    if (e.getCause() instanceof NoSuchMethodException) {
+                        throw new IllegalStateException("No create factory method exist in [" + spanExporterProviderClass.getName() + "]");
+                    } else {
+                        throw new IllegalStateException(
+                            "SpanExporter instantiation failed for class [" + spanExporterProviderClass.getName() + "]",
+                            e.getCause()
+                        );
+                    }
+                }
+            });
+        } catch (PrivilegedActionException ex) {
+            throw new IllegalStateException(
+                "SpanExporter instantiation failed for class [" + spanExporterProviderClass.getName() + "]",
+                ex.getCause()
+            );
+        }
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/package-info.java
new file mode 100644
index 0000000000000..a5fffadabd75f
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/exporter/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for telemetry.
+ */
+package org.opensearch.telemetry.tracing.exporter;
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/package-info.java
new file mode 100644
index 0000000000000..4ac1e4c212c81
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.tracing;
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java
new file mode 100644
index 0000000000000..774070aa39df6
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.sampler;
+
+import org.opensearch.telemetry.TelemetrySettings;
+
+import java.util.List;
+import java.util.Objects;
+
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.SpanKind;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.sdk.trace.data.LinkData;
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+import io.opentelemetry.sdk.trace.samplers.SamplingResult;
+
+/**
+ * ProbabilisticSampler implements a head-based sampling strategy based on provided settings.
+ */
+public class ProbabilisticSampler implements Sampler {
+    private Sampler defaultSampler;
+    private final TelemetrySettings telemetrySettings;
+    private double samplingRatio;
+
+    /**
+     * Constructor
+     *
+     * @param telemetrySettings Telemetry settings.
+     */
+    public ProbabilisticSampler(TelemetrySettings telemetrySettings) {
+        this.telemetrySettings = Objects.requireNonNull(telemetrySettings);
+        this.samplingRatio = telemetrySettings.getSamplingProbability();
+        this.defaultSampler = Sampler.traceIdRatioBased(samplingRatio);
+    }
+
+    Sampler getSampler() {
+        double newSamplingRatio = telemetrySettings.getSamplingProbability();
+        if (isSamplingRatioChanged(newSamplingRatio)) {
+            synchronized (this) {
+                this.samplingRatio = newSamplingRatio;
+                defaultSampler = Sampler.traceIdRatioBased(samplingRatio);
+            }
+        }
+        return defaultSampler;
+    }
+
+    private boolean isSamplingRatioChanged(double newSamplingRatio) {
+        return Double.compare(this.samplingRatio, newSamplingRatio) != 0;
+    }
+
+    double getSamplingRatio() {
+        return samplingRatio;
+    }
+
+    @Override
+    public SamplingResult shouldSample(
+        Context parentContext,
+        String traceId,
+        String name,
+        SpanKind spanKind,
+        Attributes attributes,
+        List<LinkData> parentLinks
+    ) {
+        return getSampler().shouldSample(parentContext, traceId, name, spanKind, attributes, parentLinks);
+    }
+
+    @Override
+    public String getDescription() {
+        return "Probabilistic Sampler";
+    }
+
+    @Override
+    public String toString() {
+        return getDescription();
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java
new file mode 100644
index 0000000000000..9ea681370a3ec
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.sampler;
+
+import java.util.List;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.SpanKind;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.sdk.trace.data.LinkData;
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+import io.opentelemetry.sdk.trace.samplers.SamplingResult;
+
+/**
+ * HeadBased sampler
+ */
+public class RequestSampler implements Sampler {
+    private final Sampler defaultSampler;
+
+    // TODO: Pick value of TRACE from PR #9415.
+    private static final String TRACE = "trace";
+
+    /**
+     * Creates Head based sampler
+     * @param defaultSampler defaultSampler
+     */
+    public RequestSampler(Sampler defaultSampler) {
+        this.defaultSampler = defaultSampler;
+    }
+
+    @Override
+    public SamplingResult shouldSample(
+        Context parentContext,
+        String traceId,
+        String name,
+        SpanKind spanKind,
+        Attributes attributes,
+        List<LinkData> parentLinks
+    ) {
+
+        final String trace = attributes.get(AttributeKey.stringKey(TRACE));
+
+        if (trace != null) {
+            return (Boolean.parseBoolean(trace) == true) ? SamplingResult.recordAndSample() : SamplingResult.drop();
+        } else {
+            return defaultSampler.shouldSample(parentContext, traceId, name, spanKind, attributes, parentLinks);
+        }
+
+    }
+
+    @Override
+    public String getDescription() {
+        return "Request Sampler";
+    }
+
+    @Override
+    public String toString() {
+        return getDescription();
+    }
+}
diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java
new file mode 100644
index 0000000000000..6534b33f6177c
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for sampler.
+ */
+package org.opensearch.telemetry.tracing.sampler;
diff --git a/plugins/telemetry-otel/src/main/plugin-metadata/plugin-security.policy b/plugins/telemetry-otel/src/main/plugin-metadata/plugin-security.policy
new file mode 100644
index 0000000000000..9d529ed5a2a56
--- /dev/null
+++ b/plugins/telemetry-otel/src/main/plugin-metadata/plugin-security.policy
@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+grant {
+    permission java.lang.RuntimePermission "getClassLoader";
+    permission java.lang.RuntimePermission "accessDeclaredMembers";
+    permission java.net.NetPermission "getProxySelector";
+    permission java.net.SocketPermission "*", "connect,resolve";
+    permission java.util.PropertyPermission "*", "read,write";
+};
+
+
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java
new file mode 100644
index 0000000000000..2fcf89947e537
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.telemetry.metrics.MetricsTelemetry;
+import org.opensearch.telemetry.metrics.OTelMetricsTelemetry;
+import org.opensearch.telemetry.tracing.OTelTracingTelemetry;
+import org.opensearch.telemetry.tracing.TracingTelemetry;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+import static org.opensearch.telemetry.OTelTelemetryPlugin.OTEL_TRACER_NAME;
+import static org.opensearch.telemetry.OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_BATCH_SIZE_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING;
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING;
+import static org.opensearch.telemetry.TelemetrySettings.TRACER_ENABLED_SETTING;
+import static org.opensearch.telemetry.TelemetrySettings.TRACER_SAMPLER_PROBABILITY;
+
+public class OTelTelemetryPluginTests extends OpenSearchTestCase {
+
+    private OTelTelemetryPlugin oTelTelemetryPlugin;
+    private Optional<Telemetry> telemetry;
+    private TracingTelemetry tracingTelemetry;
+
+    private MetricsTelemetry metricsTelemetry;
+
+    @Before
+    public void setup() {
+        // TRACER_EXPORTER_DELAY_SETTING should always be less than 10 seconds because
+        // io.opentelemetry.sdk.OpenTelemetrySdk.close waits only for 10 seconds for shutdown to complete.
+        Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build();
+        oTelTelemetryPlugin = new OTelTelemetryPlugin(settings);
+        telemetry = oTelTelemetryPlugin.getTelemetry(
+            new TelemetrySettings(Settings.EMPTY, new ClusterSettings(settings, Set.of(TRACER_ENABLED_SETTING, TRACER_SAMPLER_PROBABILITY)))
+        );
+        tracingTelemetry = telemetry.get().getTracingTelemetry();
+        metricsTelemetry = telemetry.get().getMetricsTelemetry();
+    }
+
+    public void testGetTelemetry() {
+        Set<Setting<?>> allTracerSettings = new HashSet<>();
+        ClusterSettings.FEATURE_FLAGGED_CLUSTER_SETTINGS.get(List.of(FeatureFlags.TELEMETRY)).stream().forEach((allTracerSettings::add));
+        assertEquals(OTEL_TRACER_NAME, oTelTelemetryPlugin.getName());
+        assertTrue(tracingTelemetry instanceof OTelTracingTelemetry);
+        assertTrue(metricsTelemetry instanceof OTelMetricsTelemetry);
+        assertEquals(
+            Arrays.asList(
+                TRACER_EXPORTER_BATCH_SIZE_SETTING,
+                TRACER_EXPORTER_DELAY_SETTING,
+                TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING,
+                OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING,
+                OTEL_METRICS_EXPORTER_CLASS_SETTING
+            ),
+            oTelTelemetryPlugin.getSettings()
+        );
+
+    }
+
+    @After
+    public void cleanup() throws IOException {
+        tracingTelemetry.close();
+        metricsTelemetry.close();
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetryTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetryTests.java
new file mode 100644
index 0000000000000..233c93e6b9a36
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/OTelMetricsTelemetryTests.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.telemetry.OTelAttributesConverter;
+import org.opensearch.telemetry.OTelTelemetryPlugin;
+import org.opensearch.telemetry.metrics.tags.Tags;
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.api.metrics.DoubleCounter;
+import io.opentelemetry.api.metrics.DoubleCounterBuilder;
+import io.opentelemetry.api.metrics.DoubleUpDownCounter;
+import io.opentelemetry.api.metrics.DoubleUpDownCounterBuilder;
+import io.opentelemetry.api.metrics.LongCounterBuilder;
+import io.opentelemetry.api.metrics.LongUpDownCounterBuilder;
+import io.opentelemetry.api.metrics.Meter;
+import io.opentelemetry.api.metrics.MeterProvider;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class OTelMetricsTelemetryTests extends OpenSearchTestCase {
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testCounter() {
+        String counterName = "test-counter";
+        String description = "test";
+        String unit = "1";
+        Meter mockMeter = mock(Meter.class);
+        DoubleCounter mockOTelDoubleCounter = mock(DoubleCounter.class);
+        LongCounterBuilder mockOTelLongCounterBuilder = mock(LongCounterBuilder.class);
+        DoubleCounterBuilder mockOTelDoubleCounterBuilder = mock(DoubleCounterBuilder.class);
+        MeterProvider meterProvider = mock(MeterProvider.class);
+        when(meterProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockMeter);
+        MetricsTelemetry metricsTelemetry = new OTelMetricsTelemetry(meterProvider);
+        when(mockMeter.counterBuilder(counterName)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.setDescription(description)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.setUnit(unit)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.ofDoubles()).thenReturn(mockOTelDoubleCounterBuilder);
+        when(mockOTelDoubleCounterBuilder.build()).thenReturn(mockOTelDoubleCounter);
+
+        Counter counter = metricsTelemetry.createCounter(counterName, description, unit);
+        counter.add(1.0);
+        verify(mockOTelDoubleCounter).add(1.0);
+        Tags tags = Tags.create().addTag("test", "test");
+        counter.add(2.0, tags);
+        verify(mockOTelDoubleCounter).add(2.0, OTelAttributesConverter.convert(tags));
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testCounterNegativeValue() {
+        String counterName = "test-counter";
+        String description = "test";
+        String unit = "1";
+        Meter mockMeter = mock(Meter.class);
+        DoubleCounter mockOTelDoubleCounter = mock(DoubleCounter.class);
+        LongCounterBuilder mockOTelLongCounterBuilder = mock(LongCounterBuilder.class);
+        DoubleCounterBuilder mockOTelDoubleCounterBuilder = mock(DoubleCounterBuilder.class);
+
+        MeterProvider meterProvider = mock(MeterProvider.class);
+        when(meterProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockMeter);
+        MetricsTelemetry metricsTelemetry = new OTelMetricsTelemetry(meterProvider);
+        when(mockMeter.counterBuilder(counterName)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.setDescription(description)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.setUnit(unit)).thenReturn(mockOTelLongCounterBuilder);
+        when(mockOTelLongCounterBuilder.ofDoubles()).thenReturn(mockOTelDoubleCounterBuilder);
+        when(mockOTelDoubleCounterBuilder.build()).thenReturn(mockOTelDoubleCounter);
+
+        Counter counter = metricsTelemetry.createCounter(counterName, description, unit);
+        counter.add(-1.0);
+        verify(mockOTelDoubleCounter).add(-1.0);
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testUpDownCounter() {
+        String counterName = "test-counter";
+        String description = "test";
+        String unit = "1";
+        Meter mockMeter = mock(Meter.class);
+        DoubleUpDownCounter mockOTelUpDownDoubleCounter = mock(DoubleUpDownCounter.class);
+        LongUpDownCounterBuilder mockOTelLongUpDownCounterBuilder = mock(LongUpDownCounterBuilder.class);
+        DoubleUpDownCounterBuilder mockOTelDoubleUpDownCounterBuilder = mock(DoubleUpDownCounterBuilder.class);
+
+        MeterProvider meterProvider = mock(MeterProvider.class);
+        when(meterProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockMeter);
+        MetricsTelemetry metricsTelemetry = new OTelMetricsTelemetry(meterProvider);
+        when(mockMeter.upDownCounterBuilder(counterName)).thenReturn(mockOTelLongUpDownCounterBuilder);
+        when(mockOTelLongUpDownCounterBuilder.setDescription(description)).thenReturn(mockOTelLongUpDownCounterBuilder);
+        when(mockOTelLongUpDownCounterBuilder.setUnit(unit)).thenReturn(mockOTelLongUpDownCounterBuilder);
+        when(mockOTelLongUpDownCounterBuilder.ofDoubles()).thenReturn(mockOTelDoubleUpDownCounterBuilder);
+        when(mockOTelDoubleUpDownCounterBuilder.build()).thenReturn(mockOTelUpDownDoubleCounter);
+
+        Counter counter = metricsTelemetry.createUpDownCounter(counterName, description, unit);
+        counter.add(1.0);
+        verify(mockOTelUpDownDoubleCounter).add(1.0);
+        Tags tags = Tags.create().addTag("test", "test");
+        counter.add(-2.0, tags);
+        verify(mockOTelUpDownDoubleCounter).add((-2.0), OTelAttributesConverter.convert(tags));
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/DummyMetricExporter.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/DummyMetricExporter.java
new file mode 100644
index 0000000000000..65c52911dbef9
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/DummyMetricExporter.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.exporter;
+
+import java.util.Collection;
+
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.metrics.InstrumentType;
+import io.opentelemetry.sdk.metrics.data.AggregationTemporality;
+import io.opentelemetry.sdk.metrics.data.MetricData;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+
+public class DummyMetricExporter implements MetricExporter {
+    @Override
+    public CompletableResultCode export(Collection<MetricData> metrics) {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+        return null;
+    }
+
+    @Override
+    public AggregationTemporality getAggregationTemporality(InstrumentType instrumentType) {
+        return null;
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactoryTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactoryTests.java
new file mode 100644
index 0000000000000..e68da030bfb52
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/metrics/exporter/OTelMetricsExporterFactoryTests.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics.exporter;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.exporter.logging.LoggingMetricExporter;
+import io.opentelemetry.exporter.otlp.metrics.OtlpGrpcMetricExporter;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+
+public class OTelMetricsExporterFactoryTests extends OpenSearchTestCase {
+
+    public void testMetricsExporterDefault() {
+        Settings settings = Settings.builder().build();
+        MetricExporter metricExporter = OTelMetricsExporterFactory.create(settings);
+        assertTrue(metricExporter instanceof LoggingMetricExporter);
+    }
+
+    public void testMetricsExporterLogging() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.getKey(),
+                "io.opentelemetry.exporter.logging.LoggingMetricExporter"
+            )
+            .build();
+        MetricExporter metricExporter = OTelMetricsExporterFactory.create(settings);
+        assertTrue(metricExporter instanceof LoggingMetricExporter);
+    }
+
+    public void testMetricExporterInvalid() {
+        Settings settings = Settings.builder().put(OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.getKey(), "abc").build();
+        assertThrows(IllegalArgumentException.class, () -> OTelMetricsExporterFactory.create(settings));
+    }
+
+    public void testMetricExporterNoCreateFactoryMethod() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.getKey(),
+                "org.opensearch.telemetry.metrics.exporter.DummyMetricExporter"
+            )
+            .build();
+        IllegalStateException exception = assertThrows(IllegalStateException.class, () -> OTelMetricsExporterFactory.create(settings));
+        assertEquals(
+            "MetricExporter instantiation failed for class [org.opensearch.telemetry.metrics.exporter.DummyMetricExporter]",
+            exception.getMessage()
+        );
+    }
+
+    public void testMetricExporterNonMetricExporterClass() {
+        Settings settings = Settings.builder()
+            .put(OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.getKey(), "java.lang.String")
+            .build();
+        IllegalStateException exception = assertThrows(IllegalStateException.class, () -> OTelMetricsExporterFactory.create(settings));
+        assertEquals("MetricExporter instantiation failed for class [java.lang.String]", exception.getMessage());
+        assertTrue(exception.getCause() instanceof NoSuchMethodError);
+
+    }
+
+    public void testMetricExporterGetDefaultMethod() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_METRICS_EXPORTER_CLASS_SETTING.getKey(),
+                "io.opentelemetry.exporter.otlp.metrics.OtlpGrpcMetricExporter"
+            )
+            .build();
+
+        assertTrue(OTelMetricsExporterFactory.create(settings) instanceof OtlpGrpcMetricExporter);
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelAttributesConverterTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelAttributesConverterTests.java
new file mode 100644
index 0000000000000..ee67384d01759
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelAttributesConverterTests.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.telemetry.OTelAttributesConverter;
+import org.opensearch.telemetry.metrics.tags.Tags;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Map;
+
+import io.opentelemetry.api.common.AttributeType;
+import io.opentelemetry.api.internal.InternalAttributeKeyImpl;
+
+public class OTelAttributesConverterTests extends OpenSearchTestCase {
+
+    public void testConverterNullAttributes() {
+        io.opentelemetry.api.common.Attributes otelAttributes = OTelAttributesConverter.convert((Attributes) null);
+        assertEquals(0, otelAttributes.size());
+    }
+
+    public void testConverterEmptyAttributes() {
+        Attributes attributes = Attributes.EMPTY;
+        io.opentelemetry.api.common.Attributes otelAttributes = OTelAttributesConverter.convert(attributes);
+        assertEquals(0, otelAttributes.size());
+    }
+
+    public void testConverterSingleAttributes() {
+        Attributes attributes = Attributes.create().addAttribute("key1", "value");
+        io.opentelemetry.api.common.Attributes otelAttributes = OTelAttributesConverter.convert(attributes);
+        assertEquals(1, otelAttributes.size());
+        assertEquals("value", otelAttributes.get(InternalAttributeKeyImpl.create("key1", AttributeType.STRING)));
+    }
+
+    public void testConverterMultipleAttributes() {
+        Attributes attributes = Attributes.create()
+            .addAttribute("key1", 1l)
+            .addAttribute("key2", 1.0)
+            .addAttribute("key3", true)
+            .addAttribute("key4", "value4");
+        Map<String, ?> attributeMap = attributes.getAttributesMap();
+        io.opentelemetry.api.common.Attributes otelAttributes = OTelAttributesConverter.convert(attributes);
+        assertEquals(4, otelAttributes.size());
+        otelAttributes.asMap().forEach((x, y) -> assertEquals(attributeMap.get(x.getKey()), y));
+    }
+
+    public void testConverterMultipleTags() {
+        Tags tags = Tags.create().addTag("key1", 1l).addTag("key2", 1.0).addTag("key3", true).addTag("key4", "value4");
+        Map<String, ?> tagsMap = tags.getTagsMap();
+        io.opentelemetry.api.common.Attributes otelAttributes = OTelAttributesConverter.convert(tags);
+        assertEquals(4, otelAttributes.size());
+        otelAttributes.asMap().forEach((x, y) -> assertEquals(tagsMap.get(x.getKey()), y));
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanKindConverterTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanKindConverterTests.java
new file mode 100644
index 0000000000000..d07e32d00a92a
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanKindConverterTests.java
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.api.trace.SpanKind;
+
+public class OTelSpanKindConverterTests extends OpenSearchTestCase {
+
+    public void testSpanKindNullConverterNull() {
+        assertEquals(SpanKind.INTERNAL, OTelSpanKindConverter.convert(null));
+    }
+
+    public void testSpanKindConverter() {
+        assertEquals(SpanKind.INTERNAL, OTelSpanKindConverter.convert(org.opensearch.telemetry.tracing.SpanKind.INTERNAL));
+        assertEquals(SpanKind.CLIENT, OTelSpanKindConverter.convert(org.opensearch.telemetry.tracing.SpanKind.CLIENT));
+        assertEquals(SpanKind.SERVER, OTelSpanKindConverter.convert(org.opensearch.telemetry.tracing.SpanKind.SERVER));
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanTests.java
new file mode 100644
index 0000000000000..fc92ab36908e1
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelSpanTests.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.api.trace.TraceFlags;
+import io.opentelemetry.api.trace.TraceState;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class OTelSpanTests extends OpenSearchTestCase {
+
+    private static final String TRACE_ID = "4aa59968f31dcbff7807741afa9d7d62";
+    private static final String SPAN_ID = "bea205cd25756b5e";
+
+    public void testEndSpanTest() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.endSpan();
+        verify(mockSpan).end();
+    }
+
+    public void testAddAttributeString() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.addAttribute("key", "value");
+
+        verify(mockSpan).setAttribute("key", "value");
+    }
+
+    public void testAddAttributeLong() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.addAttribute("key", 1L);
+
+        verify(mockSpan).setAttribute("key", 1L);
+    }
+
+    public void testAddAttributeDouble() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.addAttribute("key", 1.0);
+
+        verify(mockSpan).setAttribute("key", 1.0);
+    }
+
+    public void testAddAttributeBoolean() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.addAttribute("key", true);
+
+        verify(mockSpan).setAttribute("key", true);
+    }
+
+    public void testAddEvent() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+        oTelSpan.addEvent("eventName");
+
+        verify(mockSpan).addEvent("eventName");
+    }
+
+    public void testGetTraceId() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+
+        assertEquals(TRACE_ID, oTelSpan.getTraceId());
+    }
+
+    public void testGetSpanId() {
+        Span mockSpan = getMockSpan();
+        OTelSpan oTelSpan = new OTelSpan("spanName", mockSpan, null);
+
+        assertEquals(SPAN_ID, oTelSpan.getSpanId());
+    }
+
+    private Span getMockSpan() {
+        Span mockSpan = mock(Span.class);
+        when(mockSpan.getSpanContext()).thenReturn(SpanContext.create(TRACE_ID, SPAN_ID, TraceFlags.getDefault(), TraceState.getDefault()));
+        return mockSpan;
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagatorTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagatorTests.java
new file mode 100644
index 0000000000000..16a3ec9493d5d
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingContextPropagatorTests.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.api.trace.TraceFlags;
+import io.opentelemetry.api.trace.TraceState;
+import io.opentelemetry.api.trace.propagation.W3CTraceContextPropagator;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.propagation.ContextPropagators;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class OTelTracingContextPropagatorTests extends OpenSearchTestCase {
+
+    private static final String TRACE_ID = "4aa59968f31dcbff7807741afa9d7d62";
+    private static final String SPAN_ID = "bea205cd25756b5e";
+
+    public void testAddTracerContextToHeader() {
+        Span mockSpan = mock(Span.class);
+        when(mockSpan.getSpanContext()).thenReturn(SpanContext.create(TRACE_ID, SPAN_ID, TraceFlags.getDefault(), TraceState.getDefault()));
+        OTelSpan span = new OTelSpan("spanName", mockSpan, null);
+        Map<String, String> requestHeaders = new HashMap<>();
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        when(mockOpenTelemetry.getPropagators()).thenReturn(ContextPropagators.create(W3CTraceContextPropagator.getInstance()));
+        TracingContextPropagator tracingContextPropagator = new OTelTracingContextPropagator(mockOpenTelemetry);
+
+        tracingContextPropagator.inject(span, (key, value) -> requestHeaders.put(key, value));
+        assertEquals("00-" + TRACE_ID + "-" + SPAN_ID + "-00", requestHeaders.get("traceparent"));
+    }
+
+    public void testExtractTracerContextFromHeader() {
+        Map<String, String> requestHeaders = new HashMap<>();
+        requestHeaders.put("traceparent", "00-" + TRACE_ID + "-" + SPAN_ID + "-00");
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        when(mockOpenTelemetry.getPropagators()).thenReturn(ContextPropagators.create(W3CTraceContextPropagator.getInstance()));
+        TracingContextPropagator tracingContextPropagator = new OTelTracingContextPropagator(mockOpenTelemetry);
+        org.opensearch.telemetry.tracing.Span span = tracingContextPropagator.extract(requestHeaders).orElse(null);
+        assertEquals(TRACE_ID, span.getTraceId());
+        assertEquals(SPAN_ID, span.getSpanId());
+    }
+
+    public void testExtractTracerContextFromHttpHeader() {
+        Map<String, List<String>> requestHeaders = new HashMap<>();
+        requestHeaders.put("traceparent", Arrays.asList("00-" + TRACE_ID + "-" + SPAN_ID + "-00"));
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        when(mockOpenTelemetry.getPropagators()).thenReturn(ContextPropagators.create(W3CTraceContextPropagator.getInstance()));
+        TracingContextPropagator tracingContextPropagator = new OTelTracingContextPropagator(mockOpenTelemetry);
+        org.opensearch.telemetry.tracing.Span span = tracingContextPropagator.extractFromHeaders(requestHeaders).get();
+        assertEquals(TRACE_ID, span.getTraceId());
+        assertEquals(SPAN_ID, span.getSpanId());
+    }
+
+    public void testExtractTracerContextFromHttpHeaderNull() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        when(mockOpenTelemetry.getPropagators()).thenReturn(ContextPropagators.create(W3CTraceContextPropagator.getInstance()));
+        TracingContextPropagator tracingContextPropagator = new OTelTracingContextPropagator(mockOpenTelemetry);
+        org.opensearch.telemetry.tracing.Span span = tracingContextPropagator.extractFromHeaders(null).get();
+        org.opensearch.telemetry.tracing.Span propagatedSpan = new OTelPropagatedSpan(Span.fromContext(Context.root()));
+        assertEquals(propagatedSpan.getTraceId(), span.getTraceId());
+        assertEquals(propagatedSpan.getSpanId(), span.getSpanId());
+    }
+
+    public void testExtractTracerContextFromHttpHeaderEmpty() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        when(mockOpenTelemetry.getPropagators()).thenReturn(ContextPropagators.create(W3CTraceContextPropagator.getInstance()));
+        TracingContextPropagator tracingContextPropagator = new OTelTracingContextPropagator(mockOpenTelemetry);
+        org.opensearch.telemetry.tracing.Span span = tracingContextPropagator.extractFromHeaders(new HashMap<>()).get();
+        org.opensearch.telemetry.tracing.Span propagatedSpan = new OTelPropagatedSpan(Span.fromContext(Context.root()));
+        assertEquals(propagatedSpan.getTraceId(), span.getTraceId());
+        assertEquals(propagatedSpan.getSpanId(), span.getSpanId());
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingTelemetryTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingTelemetryTests.java
new file mode 100644
index 0000000000000..1a508ed252493
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/OTelTracingTelemetryTests.java
@@ -0,0 +1,133 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.telemetry.OTelTelemetryPlugin;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.api.common.AttributesBuilder;
+import io.opentelemetry.api.trace.SpanBuilder;
+import io.opentelemetry.api.trace.Tracer;
+import io.opentelemetry.api.trace.TracerProvider;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class OTelTracingTelemetryTests extends OpenSearchTestCase {
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testCreateSpanWithoutParent() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        Tracer mockTracer = mock(Tracer.class);
+        TracerProvider mockTracerProvider = mock(TracerProvider.class);
+        when(mockTracerProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockTracer);
+        SpanBuilder mockSpanBuilder = mock(SpanBuilder.class);
+        when(mockTracer.spanBuilder("span_name")).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.setAllAttributes(any(io.opentelemetry.api.common.Attributes.class))).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.startSpan()).thenReturn(mock(io.opentelemetry.api.trace.Span.class));
+        when(mockSpanBuilder.setSpanKind(any(io.opentelemetry.api.trace.SpanKind.class))).thenReturn(mockSpanBuilder);
+        Attributes attributes = Attributes.create().addAttribute("name", "value");
+        TracingTelemetry tracingTelemetry = new OTelTracingTelemetry(mockOpenTelemetry, mockTracerProvider);
+        Span span = tracingTelemetry.createSpan(SpanCreationContext.internal().name("span_name").attributes(attributes), null);
+        verify(mockSpanBuilder, never()).setParent(any());
+        verify(mockSpanBuilder).setAllAttributes(createAttribute(attributes));
+        assertNull(span.getParentSpan());
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testCreateSpanWithParent() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        Tracer mockTracer = mock(Tracer.class);
+        TracerProvider mockTracerProvider = mock(TracerProvider.class);
+        when(mockTracerProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockTracer);
+        SpanBuilder mockSpanBuilder = mock(SpanBuilder.class);
+        when(mockTracer.spanBuilder("span_name")).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.setParent(any())).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.setAllAttributes(any(io.opentelemetry.api.common.Attributes.class))).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.startSpan()).thenReturn(mock(io.opentelemetry.api.trace.Span.class));
+        when(mockSpanBuilder.setSpanKind(any(io.opentelemetry.api.trace.SpanKind.class))).thenReturn(mockSpanBuilder);
+
+        Span parentSpan = new OTelSpan("parent_span", mock(io.opentelemetry.api.trace.Span.class), null);
+
+        TracingTelemetry tracingTelemetry = new OTelTracingTelemetry(mockOpenTelemetry, mockTracerProvider);
+        Attributes attributes = Attributes.create().addAttribute("name", 1l);
+        Span span = tracingTelemetry.createSpan(SpanCreationContext.internal().name("span_name").attributes(attributes), parentSpan);
+
+        verify(mockSpanBuilder).setParent(any());
+        verify(mockSpanBuilder).setAllAttributes(createAttributeLong(attributes));
+        assertNotNull(span.getParentSpan());
+
+        assertEquals("parent_span", span.getParentSpan().getSpanName());
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testCreateSpanWithParentWithMultipleAttributes() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        Tracer mockTracer = mock(Tracer.class);
+        TracerProvider mockTracerProvider = mock(TracerProvider.class);
+        when(mockTracerProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockTracer);
+        SpanBuilder mockSpanBuilder = mock(SpanBuilder.class);
+        when(mockTracer.spanBuilder("span_name")).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.setParent(any())).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.setAllAttributes(any(io.opentelemetry.api.common.Attributes.class))).thenReturn(mockSpanBuilder);
+        when(mockSpanBuilder.startSpan()).thenReturn(mock(io.opentelemetry.api.trace.Span.class));
+        when(mockSpanBuilder.setSpanKind(any(io.opentelemetry.api.trace.SpanKind.class))).thenReturn(mockSpanBuilder);
+
+        Span parentSpan = new OTelSpan("parent_span", mock(io.opentelemetry.api.trace.Span.class), null);
+
+        TracingTelemetry tracingTelemetry = new OTelTracingTelemetry(mockOpenTelemetry, mockTracerProvider);
+        Attributes attributes = Attributes.create()
+            .addAttribute("key1", 1l)
+            .addAttribute("key2", 2.0)
+            .addAttribute("key3", true)
+            .addAttribute("key4", "key4");
+        Span span = tracingTelemetry.createSpan(SpanCreationContext.internal().name("span_name").attributes(attributes), parentSpan);
+
+        io.opentelemetry.api.common.Attributes otelAttributes = io.opentelemetry.api.common.Attributes.builder()
+            .put("key1", 1l)
+            .put("key2", 2.0)
+            .put("key3", true)
+            .put("key4", "key4")
+            .build();
+        verify(mockSpanBuilder).setParent(any());
+        verify(mockSpanBuilder).setAllAttributes(otelAttributes);
+        assertNotNull(span.getParentSpan());
+
+        assertEquals("parent_span", span.getParentSpan().getSpanName());
+    }
+
+    private io.opentelemetry.api.common.Attributes createAttribute(Attributes attributes) {
+        AttributesBuilder attributesBuilder = io.opentelemetry.api.common.Attributes.builder();
+        attributes.getAttributesMap().forEach((x, y) -> attributesBuilder.put(x, (String) y));
+        return attributesBuilder.build();
+    }
+
+    private io.opentelemetry.api.common.Attributes createAttributeLong(Attributes attributes) {
+        AttributesBuilder attributesBuilder = io.opentelemetry.api.common.Attributes.builder();
+        attributes.getAttributesMap().forEach((x, y) -> attributesBuilder.put(x, (Long) y));
+        return attributesBuilder.build();
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    public void testGetContextPropagator() {
+        OpenTelemetry mockOpenTelemetry = mock(OpenTelemetry.class);
+        Tracer mockTracer = mock(Tracer.class);
+        TracerProvider mockTracerProvider = mock(TracerProvider.class);
+        when(mockTracerProvider.get(OTelTelemetryPlugin.INSTRUMENTATION_SCOPE_NAME)).thenReturn(mockTracer);
+
+        TracingTelemetry tracingTelemetry = new OTelTracingTelemetry(mockOpenTelemetry, mockTracerProvider);
+
+        assertTrue(tracingTelemetry.getContextPropagator() instanceof OTelTracingContextPropagator);
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporter.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporter.java
new file mode 100644
index 0000000000000..8a47350a7c3bb
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporter.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.exporter;
+
+import java.util.Collection;
+
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+public class DummySpanExporter implements SpanExporter {
+    @Override
+    public CompletableResultCode export(Collection<SpanData> spans) {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+        return null;
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporterWithGetDefault.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporterWithGetDefault.java
new file mode 100644
index 0000000000000..225cfa6ab2d1a
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/DummySpanExporterWithGetDefault.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.exporter;
+
+import java.util.Collection;
+
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+public class DummySpanExporterWithGetDefault implements SpanExporter {
+
+    public static DummySpanExporterWithGetDefault getDefault() {
+        return new DummySpanExporterWithGetDefault();
+    }
+
+    @Override
+    public CompletableResultCode export(Collection<SpanData> spans) {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+        return null;
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+        return null;
+    }
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactoryTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactoryTests.java
new file mode 100644
index 0000000000000..d71aef9366e21
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/exporter/OTelSpanExporterFactoryTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.exporter;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.OTelTelemetrySettings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import io.opentelemetry.exporter.logging.LoggingSpanExporter;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+
+public class OTelSpanExporterFactoryTests extends OpenSearchTestCase {
+
+    public void testSpanExporterDefault() {
+        Settings settings = Settings.builder().build();
+        SpanExporter spanExporter = OTelSpanExporterFactory.create(settings);
+        assertTrue(spanExporter instanceof LoggingSpanExporter);
+    }
+
+    public void testSpanExporterLogging() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(),
+                "io.opentelemetry.exporter.logging.LoggingSpanExporter"
+            )
+            .build();
+        SpanExporter spanExporter = OTelSpanExporterFactory.create(settings);
+        assertTrue(spanExporter instanceof LoggingSpanExporter);
+    }
+
+    public void testSpanExporterInvalid() {
+        Settings settings = Settings.builder().put(OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(), "abc").build();
+        assertThrows(IllegalArgumentException.class, () -> OTelSpanExporterFactory.create(settings));
+    }
+
+    public void testSpanExporterNoCreateFactoryMethod() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(),
+                "org.opensearch.telemetry.tracing.exporter.DummySpanExporter"
+            )
+            .build();
+        IllegalStateException exception = assertThrows(IllegalStateException.class, () -> OTelSpanExporterFactory.create(settings));
+        assertEquals(
+            "SpanExporter instantiation failed for class [org.opensearch.telemetry.tracing.exporter.DummySpanExporter]",
+            exception.getMessage()
+        );
+    }
+
+    public void testSpanExporterNonSpanExporterClass() {
+        Settings settings = Settings.builder()
+            .put(OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(), "java.lang.String")
+            .build();
+        IllegalStateException exception = assertThrows(IllegalStateException.class, () -> OTelSpanExporterFactory.create(settings));
+        assertEquals("SpanExporter instantiation failed for class [java.lang.String]", exception.getMessage());
+        assertTrue(exception.getCause() instanceof NoSuchMethodError);
+
+    }
+
+    public void testSpanExporterGetDefaultMethod() {
+        Settings settings = Settings.builder()
+            .put(
+                OTelTelemetrySettings.OTEL_TRACER_SPAN_EXPORTER_CLASS_SETTING.getKey(),
+                "org.opensearch.telemetry.tracing.exporter.DummySpanExporterWithGetDefault"
+            )
+            .build();
+
+        assertTrue(OTelSpanExporterFactory.create(settings) instanceof DummySpanExporterWithGetDefault);
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java
new file mode 100644
index 0000000000000..639dc341ef0db
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.sampler;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Set;
+
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+
+import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING;
+import static org.opensearch.telemetry.TelemetrySettings.TRACER_ENABLED_SETTING;
+import static org.opensearch.telemetry.TelemetrySettings.TRACER_SAMPLER_PROBABILITY;
+
+public class ProbabilisticSamplerTests extends OpenSearchTestCase {
+
+    // When ProbabilisticSampler is created with OTelTelemetrySettings as null
+    public void testProbabilisticSamplerWithNullSettings() {
+        // Verify that the constructor throws IllegalArgumentException when given null settings
+        assertThrows(NullPointerException.class, () -> { new ProbabilisticSampler(null); });
+    }
+
+    public void testDefaultGetSampler() {
+        Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(
+            Settings.EMPTY,
+            new ClusterSettings(settings, Set.of(TRACER_SAMPLER_PROBABILITY, TRACER_ENABLED_SETTING))
+        );
+
+        // Probabilistic Sampler
+        ProbabilisticSampler probabilisticSampler = new ProbabilisticSampler(telemetrySettings);
+
+        assertNotNull(probabilisticSampler.getSampler());
+        assertEquals(0.01, probabilisticSampler.getSamplingRatio(), 0.0d);
+    }
+
+    public void testGetSamplerWithUpdatedSamplingRatio() {
+        Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(
+            Settings.EMPTY,
+            new ClusterSettings(settings, Set.of(TRACER_SAMPLER_PROBABILITY, TRACER_ENABLED_SETTING))
+        );
+
+        // Probabilistic Sampler
+        ProbabilisticSampler probabilisticSampler = new ProbabilisticSampler(telemetrySettings);
+        assertEquals(0.01d, probabilisticSampler.getSamplingRatio(), 0.0d);
+
+        telemetrySettings.setSamplingProbability(0.02);
+
+        // Need to call getSampler() to update the value of tracerHeadSamplerSamplingRatio
+        Sampler updatedProbabilisticSampler = probabilisticSampler.getSampler();
+        assertEquals(0.02, probabilisticSampler.getSamplingRatio(), 0.0d);
+    }
+
+}
diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java
new file mode 100644
index 0000000000000..facf04623ec46
--- /dev/null
+++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java
@@ -0,0 +1,92 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.sampler;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Collections;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.SpanKind;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+import io.opentelemetry.sdk.trace.samplers.SamplingResult;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RequestSamplerTests extends OpenSearchTestCase {
+
+    public void testShouldSampleWithTraceAttributeAsTrue() {
+
+        // Create a mock default sampler
+        Sampler defaultSampler = mock(Sampler.class);
+        when(defaultSampler.shouldSample(any(), anyString(), anyString(), any(), any(), any())).thenReturn(SamplingResult.drop());
+
+        // Create an instance of HeadSampler with the mock default sampler
+        RequestSampler requestSampler = new RequestSampler(defaultSampler);
+
+        // Create a mock Context and Attributes
+        Context parentContext = mock(Context.class);
+        Attributes attributes = Attributes.of(AttributeKey.stringKey("trace"), "true");
+
+        // Call shouldSample on HeadSampler
+        SamplingResult result = requestSampler.shouldSample(
+            parentContext,
+            "traceId",
+            "spanName",
+            SpanKind.INTERNAL,
+            attributes,
+            Collections.emptyList()
+        );
+
+        assertEquals(SamplingResult.recordAndSample(), result);
+
+        // Verify that the default sampler's shouldSample method was not called
+        verify(defaultSampler, never()).shouldSample(any(), anyString(), anyString(), any(), any(), any());
+    }
+
+    public void testShouldSampleWithoutTraceAttribute() {
+
+        // Create a mock default sampler
+        Sampler defaultSampler = mock(Sampler.class);
+        when(defaultSampler.shouldSample(any(), anyString(), anyString(), any(), any(), any())).thenReturn(
+            SamplingResult.recordAndSample()
+        );
+
+        // Create an instance of HeadSampler with the mock default sampler
+        RequestSampler requestSampler = new RequestSampler(defaultSampler);
+
+        // Create a mock Context and Attributes
+        Context parentContext = mock(Context.class);
+        Attributes attributes = Attributes.empty();
+
+        // Call shouldSample on HeadSampler
+        SamplingResult result = requestSampler.shouldSample(
+            parentContext,
+            "traceId",
+            "spanName",
+            SpanKind.INTERNAL,
+            attributes,
+            Collections.emptyList()
+        );
+
+        // Verify that HeadSampler returned SamplingResult.recordAndSample()
+        assertEquals(SamplingResult.recordAndSample(), result);
+
+        // Verify that the default sampler's shouldSample method was called
+        verify(defaultSampler).shouldSample(any(), anyString(), anyString(), any(), any(), any());
+    }
+
+}
diff --git a/plugins/transport-nio/build.gradle b/plugins/transport-nio/build.gradle
index 88355cdf22728..8c0ee8ba718ac 100644
--- a/plugins/transport-nio/build.gradle
+++ b/plugins/transport-nio/build.gradle
@@ -61,15 +61,9 @@ thirdPartyAudit {
     'com.aayushatharva.brotli4j.Brotli4jLoader',
     'com.aayushatharva.brotli4j.decoder.DecoderJNI$Status',
     'com.aayushatharva.brotli4j.decoder.DecoderJNI$Wrapper',
-    'com.aayushatharva.brotli4j.encoder.Encoder',
+    'com.aayushatharva.brotli4j.encoder.BrotliEncoderChannel',
     'com.aayushatharva.brotli4j.encoder.Encoder$Mode',
     'com.aayushatharva.brotli4j.encoder.Encoder$Parameters',
-    
-    // from io.netty.handler.codec.protobuf.ProtobufDecoder (netty)
-    'com.google.protobuf.ExtensionRegistry',
-    'com.google.protobuf.MessageLite$Builder',
-    'com.google.protobuf.MessageLite',
-    'com.google.protobuf.Parser',
 
     // from io.netty.logging.CommonsLoggerFactory (netty)
     'org.apache.commons.logging.Log',
@@ -83,6 +77,12 @@ thirdPartyAudit {
     'org.bouncycastle.cert.X509v3CertificateBuilder',
     'org.bouncycastle.cert.jcajce.JcaX509CertificateConverter',
     'org.bouncycastle.operator.jcajce.JcaContentSignerBuilder',
+    'org.bouncycastle.openssl.PEMEncryptedKeyPair',
+    'org.bouncycastle.openssl.PEMParser',
+    'org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter',
+    'org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8DecryptorProviderBuilder',
+    'org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder',
+    'org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo',
 
     // from io.netty.handler.ssl.JettyNpnSslEngine (netty)
     'org.eclipse.jetty.npn.NextProtoNego$ClientProvider',
@@ -110,15 +110,8 @@ thirdPartyAudit {
     'org.slf4j.LoggerFactory',
     'org.slf4j.spi.LocationAwareLogger',
 
-    'com.github.luben.zstd.Zstd',
-    'com.google.protobuf.ExtensionRegistryLite',
-    'com.google.protobuf.MessageLiteOrBuilder',
     'com.google.protobuf.nano.CodedOutputByteBufferNano',
     'com.google.protobuf.nano.MessageNano',
-    'com.jcraft.jzlib.Deflater',
-    'com.jcraft.jzlib.Inflater',
-    'com.jcraft.jzlib.JZlib$WrapperType',
-    'com.jcraft.jzlib.JZlib',
     'com.ning.compress.BufferRecycler',
     'com.ning.compress.lzf.ChunkDecoder',
     'com.ning.compress.lzf.ChunkEncoder',
@@ -145,6 +138,7 @@ thirdPartyAudit {
     'io.netty.internal.tcnative.AsyncSSLPrivateKeyMethod',
     'io.netty.internal.tcnative.AsyncTask',
     'io.netty.internal.tcnative.Buffer',
+    'io.netty.internal.tcnative.CertificateCompressionAlgo',
     'io.netty.internal.tcnative.Library',
     'io.netty.internal.tcnative.ResultCallback',
     'io.netty.internal.tcnative.SSL',
@@ -157,6 +151,10 @@ thirdPartyAudit {
     'io.netty.internal.tcnative.SessionTicketKey',
     'io.netty.internal.tcnative.SniHostNameMatcher',
 
+    // from  io.netty.channel.unix (netty)
+    'io.netty.channel.unix.FileDescriptor',
+    'io.netty.channel.unix.UnixChannel',
+
     'reactor.blockhound.BlockHound$Builder',
     'reactor.blockhound.integration.BlockHoundIntegration'
   )
@@ -167,7 +165,8 @@ thirdPartyAudit {
     'io.netty.util.internal.PlatformDependent0$1',
     'io.netty.util.internal.PlatformDependent0$2',
     'io.netty.util.internal.PlatformDependent0$3',
-    'io.netty.util.internal.PlatformDependent0$5',
+    'io.netty.util.internal.PlatformDependent0$4',
+    'io.netty.util.internal.PlatformDependent0$6',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueConsumerNodeRef',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseLinkedQueueProducerNodeRef',
     'io.netty.util.internal.shaded.org.jctools.queues.BaseMpscLinkedArrayQueueColdProducerFields',
@@ -180,7 +179,11 @@ thirdPartyAudit {
     'io.netty.util.internal.shaded.org.jctools.util.UnsafeAccess',
     'io.netty.util.internal.shaded.org.jctools.util.UnsafeRefArrayAccess',
 
-    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator'
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$1',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$2',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$3',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$4',
+    'io.netty.handler.ssl.util.OpenJdkSelfSignedCertGenerator$5'
   )
 }
-
diff --git a/plugins/transport-nio/licenses/netty-buffer-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-buffer-4.1.73.Final.jar.sha1
deleted file mode 100644
index e5833785ebb7e..0000000000000
--- a/plugins/transport-nio/licenses/netty-buffer-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-244a569c9aae973f6f485ac9801d79c1eca36daa
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-buffer-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-buffer-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..5b393be40e945
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-buffer-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9f02dcb9b15a647a56af210dffdc294a57922fb0
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-codec-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-codec-4.1.73.Final.jar.sha1
deleted file mode 100644
index dcdc1e4e58afe..0000000000000
--- a/plugins/transport-nio/licenses/netty-codec-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-9496a30a349863a4c6fa10d5c36b4f3b495d3a31
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-codec-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-codec-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..45ea27d29a183
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-codec-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9984cbd6e5d55c768f198e975d8aaf7fd42a4602
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-codec-http-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-codec-http-4.1.73.Final.jar.sha1
deleted file mode 100644
index 374cfb98614d5..0000000000000
--- a/plugins/transport-nio/licenses/netty-codec-http-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1ceeac4429b9bd517dc05e376a144bbe6b6bd038
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-codec-http-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-codec-http-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..6bb7fcd68b272
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-codec-http-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+7142095066eaebd5f29b88c41af7b383b6a953f6
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-common-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-common-4.1.73.Final.jar.sha1
deleted file mode 100644
index e80a6e2569d81..0000000000000
--- a/plugins/transport-nio/licenses/netty-common-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-27731b58d741b6faa6a00fa3285e7a55cc47be01
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-common-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-common-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..d53adfa649f5f
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-common-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+278f6dfa49d6bd75c40ae1470eb165716f87dce0
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-handler-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-handler-4.1.73.Final.jar.sha1
deleted file mode 100644
index 0e227997874bf..0000000000000
--- a/plugins/transport-nio/licenses/netty-handler-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1a2231c0074f88254865c3769a4b5842939ea04d
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-handler-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-handler-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..258f7c957dda0
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-handler-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+742693761d7ea4c038bccfda96bb38194720b80d
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-resolver-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-resolver-4.1.73.Final.jar.sha1
deleted file mode 100644
index ba24531724fb5..0000000000000
--- a/plugins/transport-nio/licenses/netty-resolver-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-bfe83710f0c1739019613e81a06101020ca65def
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-resolver-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-resolver-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..b8bc0a4370f58
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-resolver-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+080e45397d9d5b134477de3ffd0f94283b908621
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-transport-4.1.73.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-transport-4.1.73.Final.jar.sha1
deleted file mode 100644
index 6a8647497f210..0000000000000
--- a/plugins/transport-nio/licenses/netty-transport-4.1.73.Final.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-abb155ddff196ccedfe85b810d4b9375ef85fcfa
\ No newline at end of file
diff --git a/plugins/transport-nio/licenses/netty-transport-4.1.99.Final.jar.sha1 b/plugins/transport-nio/licenses/netty-transport-4.1.99.Final.jar.sha1
new file mode 100644
index 0000000000000..247975e0a64c7
--- /dev/null
+++ b/plugins/transport-nio/licenses/netty-transport-4.1.99.Final.jar.sha1
@@ -0,0 +1 @@
+9ca2e3ae19a6713b749df154622115f480b6716c
\ No newline at end of file
diff --git a/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/http/nio/NioPipeliningIT.java b/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/http/nio/NioPipeliningIT.java
index ac06bf03ed8cd..4f26e8ae65259 100644
--- a/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/http/nio/NioPipeliningIT.java
+++ b/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/http/nio/NioPipeliningIT.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.handler.codec.http.FullHttpResponse;
 import org.opensearch.NioIntegTestCase;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
@@ -42,6 +41,8 @@
 import java.util.Collection;
 import java.util.Locale;
 
+import io.netty.handler.codec.http.FullHttpResponse;
+
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 
diff --git a/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/transport/nio/NioTransportLoggingIT.java b/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/transport/nio/NioTransportLoggingIT.java
index 25de433e3489f..2be7730cff9e9 100644
--- a/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/transport/nio/NioTransportLoggingIT.java
+++ b/plugins/transport-nio/src/internalClusterTest/java/org/opensearch/transport/nio/NioTransportLoggingIT.java
@@ -34,12 +34,11 @@
 
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
-
 import org.opensearch.NioIntegTestCase;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsRequest;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.transport.TcpTransport;
 import org.opensearch.transport.TransportLogger;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/ByteBufUtils.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/ByteBufUtils.java
index db9ba4edd644f..d6665607af5d3 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/ByteBufUtils.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/ByteBufUtils.java
@@ -31,19 +31,20 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.CompositeByteBuf;
-import io.netty.buffer.Unpooled;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.buffer.Unpooled;
+
 class ByteBufUtils {
 
     /**
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/HttpReadWriteHandler.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/HttpReadWriteHandler.java
index 561695c06effe..d44515f3dc727 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/HttpReadWriteHandler.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/HttpReadWriteHandler.java
@@ -32,13 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.channel.ChannelHandler;
-import io.netty.handler.codec.ByteToMessageDecoder;
-import io.netty.handler.codec.http.HttpContentCompressor;
-import io.netty.handler.codec.http.HttpContentDecompressor;
-import io.netty.handler.codec.http.HttpObjectAggregator;
-import io.netty.handler.codec.http.HttpRequestDecoder;
-import io.netty.handler.codec.http.HttpResponseEncoder;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.http.HttpHandlingSettings;
 import org.opensearch.http.HttpPipelinedRequest;
@@ -58,6 +51,14 @@
 import java.util.function.BiConsumer;
 import java.util.function.LongSupplier;
 
+import io.netty.channel.ChannelHandler;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.http.HttpContentCompressor;
+import io.netty.handler.codec.http.HttpContentDecompressor;
+import io.netty.handler.codec.http.HttpObjectAggregator;
+import io.netty.handler.codec.http.HttpRequestDecoder;
+import io.netty.handler.codec.http.HttpResponseEncoder;
+
 public class HttpReadWriteHandler implements NioChannelHandler {
 
     private final NettyAdaptor adaptor;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyAdaptor.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyAdaptor.java
index 9cb224aa8decf..0b7f4ee7646d1 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyAdaptor.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyAdaptor.java
@@ -32,14 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelOutboundHandlerAdapter;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.embedded.EmbeddedChannel;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.nio.FlushOperation;
 import org.opensearch.nio.Page;
@@ -49,6 +41,15 @@
 import java.util.LinkedList;
 import java.util.function.BiConsumer;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.embedded.EmbeddedChannel;
+
 class NettyAdaptor {
 
     private final EmbeddedChannel nettyChannel;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyListener.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyListener.java
index 80b46ec99f69c..e939dbc07e471 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyListener.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NettyListener.java
@@ -32,10 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelPromise;
-import io.netty.util.concurrent.Future;
-import io.netty.util.concurrent.GenericFutureListener;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.util.concurrent.FutureUtils;
 
@@ -44,6 +40,11 @@
 import java.util.concurrent.TimeoutException;
 import java.util.function.BiConsumer;
 
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelPromise;
+import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.GenericFutureListener;
+
 /**
  * This is an {@link BiConsumer} that interfaces with netty code. It wraps a netty promise and will
  * complete that promise when accept is called. It delegates the normal promise methods to the underlying
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpChannel.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpChannel.java
index a20bb55458951..6c341b07f433d 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpChannel.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpChannel.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.http.nio;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.nio.NioSocketChannel;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpPipeliningHandler.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpPipeliningHandler.java
index aa173b51f61d1..ed1e95b1b8c69 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpPipeliningHandler.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpPipeliningHandler.java
@@ -32,9 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.channel.ChannelDuplexHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.http.HttpPipelinedRequest;
@@ -45,6 +42,10 @@
 import java.nio.channels.ClosedChannelException;
 import java.util.List;
 
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+
 /**
  * Implements HTTP pipelining ordering, ensuring that responses are completely served in the same order as their corresponding requests.
  */
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequest.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequest.java
index 73c603ffc059e..d25ef33c2ce29 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequest.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequest.java
@@ -32,22 +32,10 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.DefaultHttpHeaders;
-import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaders;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.cookie.Cookie;
-import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
-import io.netty.handler.codec.http.cookie.ServerCookieEncoder;
-
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.util.AbstractMap;
 import java.util.Collection;
@@ -58,6 +46,18 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.DefaultHttpHeaders;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.cookie.Cookie;
+import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
+import io.netty.handler.codec.http.cookie.ServerCookieEncoder;
+
 public class NioHttpRequest implements HttpRequest {
 
     private final FullHttpRequest request;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequestCreator.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequestCreator.java
index b75323b017282..27e43f4eef386 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequestCreator.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpRequestCreator.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.http.nio;
 
+import org.opensearch.ExceptionsHelper;
+
+import java.util.List;
+
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.handler.codec.http.FullHttpRequest;
-import org.opensearch.ExceptionsHelper;
-
-import java.util.List;
 
 @ChannelHandler.Sharable
 class NioHttpRequestCreator extends MessageToMessageDecoder<FullHttpRequest> {
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponse.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponse.java
index 4284b0e2948bc..c349ee14bc70f 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponse.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponse.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.http.nio;
 
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.http.HttpResponse;
+
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.http.HttpResponse;
-import org.opensearch.rest.RestStatus;
-
 public class NioHttpResponse extends DefaultFullHttpResponse implements HttpResponse {
 
     private final HttpHeaders requestHeaders;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponseCreator.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponseCreator.java
index e63ec57713b99..93822b57ec40f 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponseCreator.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpResponseCreator.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.http.nio;
 
+import org.opensearch.common.Booleans;
+import org.opensearch.monitor.jvm.JvmInfo;
+
+import java.util.List;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
@@ -40,10 +45,6 @@
 import io.netty.handler.codec.http.DefaultHttpResponse;
 import io.netty.handler.codec.http.DefaultLastHttpContent;
 import io.netty.handler.codec.http.HttpResponse;
-import org.opensearch.common.Booleans;
-import org.opensearch.monitor.jvm.JvmInfo;
-
-import java.util.List;
 
 /**
  * Split up large responses to prevent batch compression or other CPU intensive operations down the pipeline.
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerChannel.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerChannel.java
index 781a4f03da952..2c47bf009f2a3 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerChannel.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerChannel.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.http.nio;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.http.HttpServerChannel;
 import org.opensearch.nio.NioServerSocketChannel;
 
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerTransport.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerTransport.java
index 5d480794d3920..ecf9ad9f17f87 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerTransport.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/NioHttpServerTransport.java
@@ -34,17 +34,16 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.AbstractHttpServerTransport;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpServerChannel;
@@ -57,6 +56,7 @@
 import org.opensearch.nio.NioSocketChannel;
 import org.opensearch.nio.ServerChannelContext;
 import org.opensearch.nio.SocketChannelContext;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.nio.NioGroupFactory;
 import org.opensearch.transport.nio.PageAllocator;
@@ -107,9 +107,10 @@ public NioHttpServerTransport(
         NamedXContentRegistry xContentRegistry,
         Dispatcher dispatcher,
         NioGroupFactory nioGroupFactory,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
-        super(settings, networkService, bigArrays, threadPool, xContentRegistry, dispatcher, clusterSettings);
+        super(settings, networkService, bigArrays, threadPool, xContentRegistry, dispatcher, clusterSettings, tracer);
         this.pageAllocator = new PageAllocator(pageCacheRecycler);
         this.nioGroupFactory = nioGroupFactory;
 
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/PagedByteBuf.java b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/PagedByteBuf.java
index 4dc9c0935be67..221b2104e9904 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/http/nio/PagedByteBuf.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/http/nio/PagedByteBuf.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.CompositeByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.buffer.UnpooledByteBufAllocator;
-import io.netty.buffer.UnpooledHeapByteBuf;
 import org.opensearch.nio.Page;
 
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.buffer.UnpooledByteBufAllocator;
+import io.netty.buffer.UnpooledHeapByteBuf;
+
 public class PagedByteBuf extends UnpooledHeapByteBuf {
 
     private final Runnable releasable;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpChannel.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpChannel.java
index 81a07fc646907..3aa02d11dfd75 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpChannel.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpChannel.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.transport.nio;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.nio.NioSocketChannel;
 import org.opensearch.transport.TcpChannel;
 
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpServerChannel.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpServerChannel.java
index 69218f2f1fcf5..a0fb2ef4cfdf2 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpServerChannel.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTcpServerChannel.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.transport.nio;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.nio.NioServerSocketChannel;
 import org.opensearch.transport.TcpServerChannel;
 
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransport.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransport.java
index b12247c9c711c..55920bab4efd3 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransport.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransport.java
@@ -34,17 +34,16 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.nio.BytesChannelContext;
 import org.opensearch.nio.ChannelFactory;
 import org.opensearch.nio.Config;
@@ -53,6 +52,7 @@
 import org.opensearch.nio.NioSelector;
 import org.opensearch.nio.NioSocketChannel;
 import org.opensearch.nio.ServerChannelContext;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TcpTransport;
 import org.opensearch.transport.TransportSettings;
@@ -85,9 +85,10 @@ protected NioTransport(
         PageCacheRecycler pageCacheRecycler,
         NamedWriteableRegistry namedWriteableRegistry,
         CircuitBreakerService circuitBreakerService,
-        NioGroupFactory groupFactory
+        NioGroupFactory groupFactory,
+        Tracer tracer
     ) {
-        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService);
+        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService, tracer);
         this.pageAllocator = new PageAllocator(pageCacheRecycler);
         this.groupFactory = groupFactory;
     }
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
index f8816e0686e9d..d4be876867651 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
@@ -34,9 +34,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
@@ -44,12 +43,14 @@
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.nio.NioHttpServerTransport;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 
@@ -90,7 +91,8 @@ public Map<String, Supplier<Transport>> getTransports(
         PageCacheRecycler pageCacheRecycler,
         CircuitBreakerService circuitBreakerService,
         NamedWriteableRegistry namedWriteableRegistry,
-        NetworkService networkService
+        NetworkService networkService,
+        Tracer tracer
     ) {
         return Collections.singletonMap(
             NIO_TRANSPORT_NAME,
@@ -102,7 +104,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 pageCacheRecycler,
                 namedWriteableRegistry,
                 circuitBreakerService,
-                getNioGroupFactory(settings)
+                getNioGroupFactory(settings),
+                tracer
             )
         );
     }
@@ -117,7 +120,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
         NamedXContentRegistry xContentRegistry,
         NetworkService networkService,
         HttpServerTransport.Dispatcher dispatcher,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         return Collections.singletonMap(
             NIO_HTTP_TRANSPORT_NAME,
@@ -130,7 +134,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
                 xContentRegistry,
                 dispatcher,
                 getNioGroupFactory(settings),
-                clusterSettings
+                clusterSettings,
+                tracer
             )
         );
     }
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/TcpReadWriteHandler.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/TcpReadWriteHandler.java
index 1427429f0b766..0c90deed6411c 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/TcpReadWriteHandler.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/TcpReadWriteHandler.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.transport.nio;
 
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
 import org.opensearch.nio.BytesWriteHandler;
 import org.opensearch.nio.InboundChannelBuffer;
 import org.opensearch.nio.Page;
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/HttpReadWriteHandlerTests.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/HttpReadWriteHandlerTests.java
index 072664d992b78..a3f7a7822cd40 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/HttpReadWriteHandlerTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/HttpReadWriteHandlerTests.java
@@ -32,25 +32,11 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.HttpObjectAggregator;
-import io.netty.handler.codec.http.HttpRequestEncoder;
-import io.netty.handler.codec.http.HttpResponseDecoder;
-import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.handler.codec.http.HttpUtil;
-import io.netty.handler.codec.http.HttpVersion;
-
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.CorsHandler;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpHandlingSettings;
@@ -63,11 +49,8 @@
 import org.opensearch.nio.SocketChannelContext;
 import org.opensearch.nio.TaskScheduler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
-
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -76,12 +59,28 @@
 import java.util.List;
 import java.util.function.BiConsumer;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpObjectAggregator;
+import io.netty.handler.codec.http.HttpRequestEncoder;
+import io.netty.handler.codec.http.HttpResponseDecoder;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.HttpUtil;
+import io.netty.handler.codec.http.HttpVersion;
+import org.mockito.ArgumentCaptor;
+
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_MAX_CONTENT_LENGTH;
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_READ_TIMEOUT;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NettyAdaptorTests.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NettyAdaptorTests.java
index 9ba27802822ea..21634725d5279 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NettyAdaptorTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NettyAdaptorTests.java
@@ -32,13 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.channel.ChannelOutboundHandlerAdapter;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.SimpleChannelInboundHandler;
 import org.opensearch.nio.FlushOperation;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -47,6 +40,14 @@
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.SimpleChannelInboundHandler;
+
 public class NettyAdaptorTests extends OpenSearchTestCase {
 
     public void testBasicRead() {
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpClient.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpClient.java
index 1229aab244a6d..45e51c6855f79 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpClient.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpClient.java
@@ -32,28 +32,15 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelHandler;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.DefaultFullHttpResponse;
-import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpContentDecompressor;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.HttpObjectAggregator;
-import io.netty.handler.codec.http.HttpRequest;
-import io.netty.handler.codec.http.HttpRequestEncoder;
-import io.netty.handler.codec.http.HttpResponse;
-import io.netty.handler.codec.http.HttpResponseDecoder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.nio.BytesChannelContext;
 import org.opensearch.nio.ChannelFactory;
 import org.opensearch.nio.Config;
@@ -83,9 +70,23 @@
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandler;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.DefaultFullHttpResponse;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpContentDecompressor;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpObjectAggregator;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpRequestEncoder;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.HttpResponseDecoder;
+
+import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
 import static io.netty.handler.codec.http.HttpHeaderNames.HOST;
 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
-import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
 import static org.junit.Assert.fail;
 
 /**
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpPipeliningHandlerTests.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpPipeliningHandlerTests.java
index 70da3496c2534..46cf6ae708d1c 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpPipeliningHandlerTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpPipeliningHandlerTests.java
@@ -32,26 +32,15 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBufUtil;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPromise;
-import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.channel.embedded.EmbeddedChannel;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.QueryStringDecoder;
-
 import org.opensearch.common.Randomness;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.http.HttpPipelinedRequest;
 import org.opensearch.http.HttpPipelinedResponse;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.http.HttpResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
-
 import org.junit.After;
 
 import java.nio.channels.ClosedChannelException;
@@ -67,9 +56,19 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import io.netty.buffer.ByteBufUtil;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.QueryStringDecoder;
+
+import static org.hamcrest.core.Is.is;
 import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
-import static org.hamcrest.core.Is.is;
 
 public class NioHttpPipeliningHandlerTests extends OpenSearchTestCase {
 
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpServerTransportTests.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpServerTransportTests.java
index 9106e9608c778..09594673de5b2 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpServerTransportTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/NioHttpServerTransportTests.java
@@ -32,49 +32,36 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.Unpooled;
-import io.netty.handler.codec.TooLongFrameException;
-import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaderValues;
-import io.netty.handler.codec.http.HttpMethod;
-import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.handler.codec.http.HttpUtil;
-import io.netty.handler.codec.http.HttpVersion;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.http.BindHttpException;
 import org.opensearch.http.CorsHandler;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpTransportSettings;
 import org.opensearch.http.NullDispatcher;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.nio.NioSocketChannel;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.nio.NioGroupFactory;
-
 import org.junit.After;
 import org.junit.Before;
 
@@ -86,10 +73,23 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
+import io.netty.buffer.ByteBufUtil;
+import io.netty.buffer.Unpooled;
+import io.netty.handler.codec.TooLongFrameException;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaderValues;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.HttpUtil;
+import io.netty.handler.codec.http.HttpVersion;
+
+import static org.opensearch.core.rest.RestStatus.BAD_REQUEST;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ALLOW_ORIGIN;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ENABLED;
-import static org.opensearch.rest.RestStatus.BAD_REQUEST;
-import static org.opensearch.rest.RestStatus.OK;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
@@ -187,7 +187,8 @@ public void dispatchBadRequest(RestChannel channel, ThreadContext threadContext,
                 xContentRegistry(),
                 dispatcher,
                 new NioGroupFactory(settings, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -237,7 +238,8 @@ public void testBindUnavailableAddress() {
                 xContentRegistry(),
                 new NullDispatcher(),
                 new NioGroupFactory(Settings.EMPTY, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -256,7 +258,8 @@ public void testBindUnavailableAddress() {
                     xContentRegistry(),
                     new NullDispatcher(),
                     new NioGroupFactory(Settings.EMPTY, logger),
-                    new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                    new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                    NoopTracer.INSTANCE
                 )
             ) {
                 BindHttpException bindHttpException = expectThrows(BindHttpException.class, () -> otherTransport.start());
@@ -299,7 +302,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new NioGroupFactory(settings, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -373,7 +377,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new NioGroupFactory(Settings.EMPTY, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -439,7 +444,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new NioGroupFactory(settings, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
@@ -501,7 +507,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 xContentRegistry(),
                 dispatcher,
                 new NioGroupFactory(settings, logger),
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             )
         ) {
             transport.start();
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/PagedByteBufTests.java b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/PagedByteBufTests.java
index de53cdad104df..c540c1854e509 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/http/nio/PagedByteBufTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/http/nio/PagedByteBufTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.http.nio;
 
-import io.netty.buffer.ByteBuf;
 import org.opensearch.nio.Page;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -40,6 +39,8 @@
 import java.util.ArrayList;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import io.netty.buffer.ByteBuf;
+
 public class PagedByteBufTests extends OpenSearchTestCase {
 
     public void testReleasingPage() {
diff --git a/plugins/transport-nio/src/test/java/org/opensearch/transport/nio/SimpleNioTransportTests.java b/plugins/transport-nio/src/test/java/org/opensearch/transport/nio/SimpleNioTransportTests.java
index c8b9fa63383bf..f5d1c618f5ace 100644
--- a/plugins/transport-nio/src/test/java/org/opensearch/transport/nio/SimpleNioTransportTests.java
+++ b/plugins/transport-nio/src/test/java/org/opensearch/transport/nio/SimpleNioTransportTests.java
@@ -33,18 +33,18 @@
 package org.opensearch.transport.nio;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.core.internal.net.NetUtils;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.common.util.net.NetUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.test.transport.StubbableTransport;
 import org.opensearch.transport.AbstractSimpleTransportTestCase;
@@ -82,7 +82,8 @@ protected Transport build(Settings settings, final Version version, ClusterSetti
             new MockPageCacheRecycler(settings),
             namedWriteableRegistry,
             new NoneCircuitBreakerService(),
-            new NioGroupFactory(settings, logger)
+            new NioGroupFactory(settings, logger),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -122,10 +123,7 @@ public void testConnectException() throws UnknownHostException {
     }
 
     public void testDefaultKeepAliveSettings() throws IOException {
-        assumeTrue(
-            "setting default keepalive options not supported on this platform",
-            (IOUtils.LINUX || IOUtils.MAC_OS_X) && JavaVersion.current().compareTo(JavaVersion.parse("11")) >= 0
-        );
+        assumeTrue("setting default keepalive options not supported on this platform", (IOUtils.LINUX || IOUtils.MAC_OS_X));
         try (
             MockTransportService serviceC = buildService("TS_C", Version.CURRENT, Settings.EMPTY);
             MockTransportService serviceD = buildService("TS_D", Version.CURRENT, Settings.EMPTY)
diff --git a/protobuf-java-NOTICE.txt b/protobuf-java-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/qa/ccs-unavailable-clusters/src/test/java/org/opensearch/search/CrossClusterSearchUnavailableClusterIT.java b/qa/ccs-unavailable-clusters/src/test/java/org/opensearch/search/CrossClusterSearchUnavailableClusterIT.java
index 5691154882c9f..c6380c69a1c95 100644
--- a/qa/ccs-unavailable-clusters/src/test/java/org/opensearch/search/CrossClusterSearchUnavailableClusterIT.java
+++ b/qa/ccs-unavailable-clusters/src/test/java/org/opensearch/search/CrossClusterSearchUnavailableClusterIT.java
@@ -61,12 +61,13 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.internal.InternalSearchResponse;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -118,7 +119,7 @@ private static MockTransportService startTransport(
         boolean success = false;
         final Settings s = Settings.builder().put("node.name", id).build();
         ClusterName clusterName = ClusterName.CLUSTER_NAME_SETTING.get(s);
-        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, null);
+        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, NoopTracer.INSTANCE);
         try {
             newService.registerRequestHandler(ClusterSearchShardsAction.NAME, ThreadPool.Names.SAME, ClusterSearchShardsRequest::new,
                 (request, channel, task) -> {
@@ -341,7 +342,7 @@ private static HttpEntity buildUpdateSettingsRequestBody(Map<String, Object> set
                 builder.endObject();
             }
             builder.endObject();
-            requestBody = Strings.toString(builder);
+            requestBody = builder.toString();
         }
         return new NStringEntity(requestBody, ContentType.APPLICATION_JSON);
     }
diff --git a/qa/die-with-dignity/build.gradle b/qa/die-with-dignity/build.gradle
index 008e2e19bf72f..db8762fe921bf 100644
--- a/qa/die-with-dignity/build.gradle
+++ b/qa/die-with-dignity/build.gradle
@@ -35,4 +35,3 @@ testClusters.javaRestTest {
 }
 
 test.enabled = false
-
diff --git a/qa/die-with-dignity/src/javaRestTest/java/org/opensearch/qa/die_with_dignity/DieWithDignityIT.java b/qa/die-with-dignity/src/javaRestTest/java/org/opensearch/qa/die_with_dignity/DieWithDignityIT.java
index ec891ef8d44ef..8a2bb3e8be38a 100644
--- a/qa/die-with-dignity/src/javaRestTest/java/org/opensearch/qa/die_with_dignity/DieWithDignityIT.java
+++ b/qa/die-with-dignity/src/javaRestTest/java/org/opensearch/qa/die_with_dignity/DieWithDignityIT.java
@@ -76,7 +76,7 @@ public void testDieWithDignity() throws Exception {
         try {
             while (it.hasNext() && (fatalError == false || fatalErrorInThreadExiting == false)) {
                 final String line = it.next();
-                if (line.matches(".*ERROR.*o\\.o\\.ExceptionsHelper.*javaRestTest-0.*fatal error.*")) {
+                if (line.matches(".*ERROR.*o\\.o\\.(Base)?ExceptionsHelper.*javaRestTest-0.*fatal error.*")) {
                     fatalError = true;
                 } else if (line.matches(
                     ".*ERROR.*o\\.o\\.b\\.OpenSearchUncaughtExceptionHandler.*javaRestTest-0.*"
diff --git a/qa/evil-tests/build.gradle b/qa/evil-tests/build.gradle
index 19dc72c0c784f..fab925d887847 100644
--- a/qa/evil-tests/build.gradle
+++ b/qa/evil-tests/build.gradle
@@ -40,7 +40,7 @@ apply plugin: 'opensearch.testclusters'
 apply plugin: 'opensearch.standalone-test'
 
 dependencies {
-  testImplementation 'com.google.jimfs:jimfs:1.2'
+  testImplementation 'com.google.jimfs:jimfs:1.3.0'
 }
 
 // TODO: give each evil test its own fresh JVM for more isolation.
@@ -62,7 +62,6 @@ thirdPartyAudit {
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$1',
     'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$2',
-    'com.google.common.hash.LittleEndianByteArray$UnsafeByteArray$3',
     'com.google.common.hash.Striped64',
     'com.google.common.hash.Striped64$1',
     'com.google.common.hash.Striped64$Cell',
diff --git a/qa/evil-tests/src/test/java/org/opensearch/common/logging/EvilLoggerTests.java b/qa/evil-tests/src/test/java/org/opensearch/common/logging/EvilLoggerTests.java
index 9319d11ebae98..a44bd0ee4b32f 100644
--- a/qa/evil-tests/src/test/java/org/opensearch/common/logging/EvilLoggerTests.java
+++ b/qa/evil-tests/src/test/java/org/opensearch/common/logging/EvilLoggerTests.java
@@ -62,7 +62,6 @@
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
-import java.util.Set;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
 import java.util.regex.Matcher;
@@ -299,7 +298,7 @@ public void testNoNodeNameInPatternWarning() throws IOException, UserException {
         // the first message is a warning for unsupported configuration files
         assertLogLine(events.get(0), Level.WARN, location, "\\[" + nodeName + "\\] Some logging configurations have "
                 + "%marker but don't have %node_name. We will automatically add %node_name to the pattern to ease the "
-                + "migration for users who customize log4j2.properties but will stop this behavior in 7.0. You should "
+                + "migration for users who customize log4j2.properties but will stop this behavior in 3.0. You should "
                 + "manually replace `%node_name` with `\\[%node_name\\]%marker ` in these locations:");
         if (Constants.WINDOWS) {
             assertThat(events.get(1), endsWith("no_node_name\\log4j2.properties"));
diff --git a/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool-cmd1.help b/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool-cmd1.help
index d083e3a65348f..60acabffb6544 100644
--- a/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool-cmd1.help
+++ b/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool-cmd1.help
@@ -1 +1 @@
-cmd1 help
\ No newline at end of file
+cmd1 help
diff --git a/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool.help b/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool.help
index 023b1accdffb1..2a5850ba79db2 100644
--- a/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool.help
+++ b/qa/evil-tests/src/test/resources/org/opensearch/common/cli/tool.help
@@ -1 +1 @@
-tool help
\ No newline at end of file
+tool help
diff --git a/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/FullClusterRestartIT.java b/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/FullClusterRestartIT.java
index a8302fdd6bc76..53bac56ab8675 100644
--- a/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/FullClusterRestartIT.java
+++ b/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/FullClusterRestartIT.java
@@ -43,11 +43,13 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.test.NotEqualMessageBuilder;
 import org.opensearch.test.XContentTestUtils;
@@ -149,7 +151,7 @@ public void testSearch() throws Exception {
             mappingsAndSettings.endObject();
 
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             createIndex.setOptions(allowTypesRemovalWarnings());
             client().performRequest(createIndex);
 
@@ -208,7 +210,7 @@ public void testNewReplicasWork() throws Exception {
             mappingsAndSettings.endObject();
 
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createIndex);
 
             int numDocs = randomIntBetween(2000, 3000);
@@ -257,7 +259,7 @@ public void testClusterState() throws Exception {
             }
             mappingsAndSettings.endObject();
             Request createTemplate = new Request("PUT", "/_template/template_1");
-            createTemplate.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createTemplate.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createTemplate);
             client().performRequest(new Request("PUT", "/" + index));
         }
@@ -315,7 +317,7 @@ public void testShrink() throws IOException {
             mappingsAndSettings.endObject();
 
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createIndex);
 
             numDocs = randomIntBetween(512, 1024);
@@ -387,7 +389,7 @@ public void testShrinkAfterUpgrade() throws IOException {
             mappingsAndSettings.endObject();
 
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createIndex);
 
             numDocs = randomIntBetween(512, 1024);
@@ -659,7 +661,7 @@ public void testEmptyShard() throws IOException {
                 .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                 .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                 // if the node with the replica is the first to be restarted, while a replica is still recovering
-                // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                 // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                 // before timing out
                 .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
@@ -857,7 +859,7 @@ public void testSnapshotRestore() throws IOException {
         }
         templateBuilder.endObject().endObject();
         Request createTemplateRequest = new Request("PUT", "/_template/test_template");
-        createTemplateRequest.setJsonEntity(Strings.toString(templateBuilder));
+        createTemplateRequest.setJsonEntity(templateBuilder.toString());
 
         client().performRequest(createTemplateRequest);
 
@@ -873,7 +875,7 @@ public void testSnapshotRestore() throws IOException {
             }
             repoConfig.endObject();
             Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
-            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
+            createRepoRequest.setJsonEntity(repoConfig.toString());
             client().performRequest(createRepoRequest);
         }
 
@@ -900,7 +902,7 @@ public void testHistoryUUIDIsAdded() throws Exception {
             }
             mappingsAndSettings.endObject();
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createIndex);
         } else {
             ensureGreenLongWait(index);
@@ -943,11 +945,11 @@ public void testSoftDeletes() throws Exception {
             }
             mappingsAndSettings.endObject();
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
+            createIndex.setJsonEntity(mappingsAndSettings.toString());
             client().performRequest(createIndex);
             int numDocs = between(10, 100);
             for (int i = 0; i < numDocs; i++) {
-                String doc = Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v1").endObject());
+                String doc = JsonXContent.contentBuilder().startObject().field("field", "v1").endObject().toString();
                 Request request = new Request("POST", "/" + index + "/_doc/" + i);
                 request.setJsonEntity(doc);
                 client().performRequest(request);
@@ -958,7 +960,7 @@ public void testSoftDeletes() throws Exception {
             assertTotalHits(liveDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
             for (int i = 0; i < numDocs; i++) {
                 if (randomBoolean()) {
-                    String doc = Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v2").endObject());
+                    String doc = JsonXContent.contentBuilder().startObject().field("field", "v2").endObject().toString();
                     Request request = new Request("POST", "/" + index + "/_doc/" + i);
                     request.setJsonEntity(doc);
                     client().performRequest(request);
@@ -992,7 +994,7 @@ public void testClosedIndices() throws Exception {
                 numDocs = between(1, 100);
                 for (int i = 0; i < numDocs; i++) {
                     final Request request = new Request("POST", "/" + index + "/" + type + "/" + i);
-                    request.setJsonEntity(Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v1").endObject()));
+                    request.setJsonEntity(JsonXContent.contentBuilder().startObject().field("field", "v1").endObject().toString());
                     assertOK(client().performRequest(request));
                     if (rarely()) {
                         refresh();
@@ -1090,7 +1092,7 @@ private void checkSnapshot(final String snapshotName, final int count, final Ver
         restoreCommand.endObject();
         Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshotName + "/_restore");
         restoreRequest.addParameter("wait_for_completion", "true");
-        restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
+        restoreRequest.setJsonEntity(restoreCommand.toString());
         client().performRequest(restoreRequest);
 
         // Make sure search finds all documents
@@ -1165,7 +1167,7 @@ private void indexRandomDocuments(
         for (int i = 0; i < count; i++) {
             logger.debug("Indexing document [{}]", i);
             Request createDocument = new Request("POST", "/" + index + "/_doc/" + (specifyId ? i : ""));
-            createDocument.setJsonEntity(Strings.toString(docSupplier.apply(i)));
+            createDocument.setJsonEntity(docSupplier.apply(i).toString());
             client().performRequest(createDocument);
             if (rarely()) {
                 refreshAllIndices();
@@ -1182,7 +1184,7 @@ private void indexRandomDocuments(
 
     private void indexDocument(String id) throws IOException {
         final Request indexRequest = new Request("POST", "/" + index + "/" + type + "/" + id);
-        indexRequest.setJsonEntity(Strings.toString(JsonXContent.contentBuilder().startObject().field("f", "v").endObject()));
+        indexRequest.setJsonEntity(JsonXContent.contentBuilder().startObject().field("f", "v").endObject().toString());
         assertOK(client().performRequest(indexRequest));
     }
 
@@ -1197,7 +1199,7 @@ private void saveInfoDocument(String id, String value) throws IOException {
         // Only create the first version so we know how many documents are created when the index is first created
         Request request = new Request("PUT", "/info/" + type + "/" + id);
         request.addParameter("op_type", "create");
-        request.setJsonEntity(Strings.toString(infoDoc));
+        request.setJsonEntity(infoDoc.toString());
         client().performRequest(request);
     }
 
@@ -1262,7 +1264,7 @@ public void testPeerRecoveryRetentionLeases() throws Exception {
             settings.endObject();
 
             Request createIndex = new Request("PUT", "/" + index);
-            createIndex.setJsonEntity(Strings.toString(settings));
+            createIndex.setJsonEntity(settings.toString());
             client().performRequest(createIndex);
         }
         ensureGreen(index);
@@ -1372,7 +1374,7 @@ public void testResize() throws Exception {
                 if (randomBoolean()) {
                     settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true);
                 }
-                shrinkRequest.setJsonEntity("{\"settings\":" + Strings.toString(settings.build()) + "}");
+                shrinkRequest.setJsonEntity("{\"settings\":" + Strings.toString(MediaTypeRegistry.JSON, settings.build()) + "}");
                 client().performRequest(shrinkRequest);
                 ensureGreenLongWait(target);
                 assertNumHits(target, numDocs + moreDocs, 1);
@@ -1384,7 +1386,7 @@ public void testResize() throws Exception {
                     settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true);
                 }
                 Request splitRequest = new Request("PUT", "/" + index + "/_split/" + target);
-                splitRequest.setJsonEntity("{\"settings\":" + Strings.toString(settings.build()) + "}");
+                splitRequest.setJsonEntity("{\"settings\":" + Strings.toString(MediaTypeRegistry.JSON, settings.build()) + "}");
                 client().performRequest(splitRequest);
                 ensureGreenLongWait(target);
                 assertNumHits(target, numDocs + moreDocs, 6);
@@ -1523,7 +1525,7 @@ public void testEnableSoftDeletesOnRestore() throws Exception {
             }
             repoConfig.endObject();
             Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
-            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
+            createRepoRequest.setJsonEntity(repoConfig.toString());
             client().performRequest(createRepoRequest);
             // create snapshot
             Request createSnapshot = new Request("PUT", "/_snapshot/repo/" + snapshot);
@@ -1545,7 +1547,7 @@ public void testEnableSoftDeletesOnRestore() throws Exception {
             restoreCommand.endObject();
             Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshot + "/_restore");
             restoreRequest.addParameter("wait_for_completion", "true");
-            restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
+            restoreRequest.setJsonEntity(restoreCommand.toString());
             client().performRequest(restoreRequest);
             ensureGreen(restoredIndex);
             int numDocs = countOfIndexedRandomDocuments();
@@ -1577,7 +1579,7 @@ public void testForbidDisableSoftDeletesOnRestore() throws Exception {
             }
             repoConfig.endObject();
             Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
-            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
+            createRepoRequest.setJsonEntity(repoConfig.toString());
             client().performRequest(createRepoRequest);
             // create snapshot
             Request createSnapshot = new Request("PUT", "/_snapshot/repo/" + snapshot);
@@ -1598,7 +1600,7 @@ public void testForbidDisableSoftDeletesOnRestore() throws Exception {
             restoreCommand.endObject();
             Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshot + "/_restore");
             restoreRequest.addParameter("wait_for_completion", "true");
-            restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
+            restoreRequest.setJsonEntity(restoreCommand.toString());
             final ResponseException error = expectThrows(ResponseException.class, () -> client().performRequest(restoreRequest));
             assertThat(error.getMessage(), containsString("cannot disable setting [index.soft_deletes.enabled] on restore"));
         }
diff --git a/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/QueryBuilderBWCIT.java b/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/QueryBuilderBWCIT.java
index de042cb2b7634..1648f345104ea 100644
--- a/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/QueryBuilderBWCIT.java
+++ b/qa/full-cluster-restart/src/test/java/org/opensearch/upgrades/QueryBuilderBWCIT.java
@@ -36,16 +36,15 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.ConstantScoreQueryBuilder;
 import org.opensearch.index.query.DisMaxQueryBuilder;
@@ -198,7 +197,7 @@ public void testQueryBuilderBWC() throws Exception {
             mappingsAndSettings.endObject();
             Request request = new Request("PUT", "/" + index);
             request.setOptions(allowTypesRemovalWarnings());
-            request.setJsonEntity(Strings.toString(mappingsAndSettings));
+            request.setJsonEntity(mappingsAndSettings.toString());
             Response rsp = client().performRequest(request);
             assertEquals(200, rsp.getStatusLine().getStatusCode());
 
diff --git a/qa/logging-config/src/test/java/org/opensearch/common/logging/JsonLoggerTests.java b/qa/logging-config/src/test/java/org/opensearch/common/logging/JsonLoggerTests.java
index c760677aa3cd0..7fbfd6929ebdf 100644
--- a/qa/logging-config/src/test/java/org/opensearch/common/logging/JsonLoggerTests.java
+++ b/qa/logging-config/src/test/java/org/opensearch/common/logging/JsonLoggerTests.java
@@ -43,7 +43,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.env.Environment;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.FeatureMatcher;
diff --git a/qa/logging-config/src/test/java/org/opensearch/common/logging/OpenSearchJsonLayoutTests.java b/qa/logging-config/src/test/java/org/opensearch/common/logging/OpenSearchJsonLayoutTests.java
index 6639d53c9c879..0a8bd46ac96f3 100644
--- a/qa/logging-config/src/test/java/org/opensearch/common/logging/OpenSearchJsonLayoutTests.java
+++ b/qa/logging-config/src/test/java/org/opensearch/common/logging/OpenSearchJsonLayoutTests.java
@@ -66,6 +66,46 @@ public void testLayout() {
                 "%exceptionAsJson }" + System.lineSeparator()));
     }
 
+    public void testWithMaxMessageLengthLayout() {
+        OpenSearchJsonLayout server = OpenSearchJsonLayout.newBuilder()
+            .setType("server")
+            .setMaxMessageLength(42)
+            .build();
+        String conversionPattern = server.getPatternLayout().getConversionPattern();
+
+        assertThat(conversionPattern, Matchers.equalTo(
+            "{" +
+                "\"type\": \"server\", " +
+                "\"timestamp\": \"%d{yyyy-MM-dd'T'HH:mm:ss,SSSZZ}\", " +
+                "\"level\": \"%p\", " +
+                "\"component\": \"%c{1.}\", " +
+                "\"cluster.name\": \"${sys:opensearch.logs.cluster_name}\", " +
+                "\"node.name\": \"%node_name\", " +
+                "\"message\": \"%notEmpty{%enc{%marker}{JSON} }%enc{%.-42m}{JSON}\"" +
+                "%notEmpty{, %node_and_cluster_id }" +
+                "%exceptionAsJson }" + System.lineSeparator()));
+    }
+
+    public void testWithUnrestrictedMaxMessageLengthLayout() {
+        OpenSearchJsonLayout server = OpenSearchJsonLayout.newBuilder()
+            .setType("server")
+            .setMaxMessageLength(0)
+            .build();
+        String conversionPattern = server.getPatternLayout().getConversionPattern();
+
+        assertThat(conversionPattern, Matchers.equalTo(
+            "{" +
+                "\"type\": \"server\", " +
+                "\"timestamp\": \"%d{yyyy-MM-dd'T'HH:mm:ss,SSSZZ}\", " +
+                "\"level\": \"%p\", " +
+                "\"component\": \"%c{1.}\", " +
+                "\"cluster.name\": \"${sys:opensearch.logs.cluster_name}\", " +
+                "\"node.name\": \"%node_name\", " +
+                "\"message\": \"%notEmpty{%enc{%marker}{JSON} }%enc{%m}{JSON}\"" +
+                "%notEmpty{, %node_and_cluster_id }" +
+                "%exceptionAsJson }" + System.lineSeparator()));
+    }
+
     public void testLayoutWithAdditionalFields() {
         OpenSearchJsonLayout server = OpenSearchJsonLayout.newBuilder()
                                           .setType("server")
diff --git a/qa/mixed-cluster/build.gradle b/qa/mixed-cluster/build.gradle
index 7a2c37639b93e..822977c55368a 100644
--- a/qa/mixed-cluster/build.gradle
+++ b/qa/mixed-cluster/build.gradle
@@ -38,6 +38,10 @@ apply plugin: 'opensearch.standalone-test'
 apply from : "$rootDir/gradle/bwc-test.gradle"
 apply plugin: 'opensearch.rest-resources'
 
+dependencies {
+  testImplementation project(":client:rest-high-level")
+}
+
 restResources {
   restTests {
     includeCore '*'
@@ -51,6 +55,7 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
   }
 
   String baseName = "v${bwcVersion}"
+  String bwcVersionStr = "${bwcVersion}"
 
   /* This project runs the core REST tests against a 4 node cluster where two of
      the nodes has a different minor.  */
@@ -81,6 +86,7 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
       nonInputProperties.systemProperty('tests.rest.cluster', "${-> testClusters."${baseName}".allHttpSocketURI.join(",")}")
       nonInputProperties.systemProperty('tests.clustername', "${-> testClusters."${baseName}".getName()}")
     }
+    systemProperty 'tests.upgrade_from_version', bwcVersionStr
     systemProperty 'tests.path.repo', "${buildDir}/cluster/shared/repo/${baseName}"
     onlyIf { project.bwc_tests_enabled }
   }
diff --git a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/ExceptionIT.java b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/ExceptionIT.java
index e0246870181c0..d8207ecb9b5c5 100644
--- a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/ExceptionIT.java
+++ b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/ExceptionIT.java
@@ -47,7 +47,13 @@ public void testOpensearchException() throws Exception {
     private void logClusterNodes() throws IOException {
         ObjectPath objectPath = ObjectPath.createFromResponse(client().performRequest(new Request("GET", "_nodes")));
         Map<String, ?> nodes = objectPath.evaluate("nodes");
-        String master = EntityUtils.toString(client().performRequest(new Request("GET", "_cat/master?h=id")).getEntity()).trim();
+        Request request = new Request("GET", "_cat/master?h=id");
+        String inclusiveWarning = "[GET /_cat/master] is deprecated! Use [GET /_cat/cluster_manager] instead.";
+        request.setOptions(expectVersionSpecificWarnings(v -> {
+            v.current(inclusiveWarning);
+            v.compatible(inclusiveWarning);
+        }));
+        String master = EntityUtils.toString(client().performRequest(request).getEntity()).trim();
         logger.info("cluster discovered: master id='{}'", master);
         for (String id : nodes.keySet()) {
             logger.info("{}: id='{}', name='{}', version={}",
diff --git a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
index b133a6462a525..b31706d5e2d2f 100644
--- a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
+++ b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
@@ -32,6 +32,10 @@
 package org.opensearch.backwards;
 
 import org.apache.http.HttpHost;
+import org.apache.http.ParseException;
+
+
+import org.apache.http.util.EntityUtils;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.client.Request;
@@ -40,12 +44,13 @@
 import org.opensearch.client.ResponseException;
 import org.opensearch.client.RestClient;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.seqno.SeqNoStats;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.opensearch.test.rest.yaml.ObjectPath;
 
@@ -62,11 +67,15 @@
 
 public class IndexingIT extends OpenSearchRestTestCase {
 
+    protected static final Version UPGRADE_FROM_VERSION = Version.fromString(System.getProperty("tests.upgrade_from_version"));
+    private static final String TEST_MAPPING = createTestMapping();
+
+
     private int indexDocs(String index, final int idStart, final int numDocs) throws IOException {
         for (int i = 0; i < numDocs; i++) {
             final int id = idStart + i;
             Request request = new Request("PUT", index + "/_doc/" + id);
-            request.setJsonEntity("{\"test\": \"test_" + randomAlphaOfLength(2) + "\"}");
+            request.setJsonEntity("{\"test\": \"test_" + randomAlphaOfLength(2) + "\", \"sortfield\": \""+ randomIntBetween(0, numDocs) + "\"}");
             assertOK(client().performRequest(request));
         }
         return numDocs;
@@ -97,6 +106,113 @@ private int indexDocWithConcurrentUpdates(String index, final int docId, int nUp
         return nUpdates + 1;
     }
 
+    private void printClusterRouting() throws IOException, ParseException {
+        Request clusterStateRequest = new Request("GET", "_cluster/state/routing_nodes?pretty");
+        String clusterState = EntityUtils.toString(client().performRequest(clusterStateRequest).getEntity()).trim();
+        logger.info("cluster nodes: {}", clusterState);
+    }
+
+    /**
+     * This test verifies that segment replication does not break when primary shards are on lower OS version. It does this
+     * by verifying replica shards contains same number of documents as primary's.
+     *
+     * @throws Exception
+     */
+    public void testIndexingWithPrimaryOnBwcNodes() throws Exception {
+        if (UPGRADE_FROM_VERSION.before(Version.V_2_4_0)) {
+            logger.info("--> Skip test for version {} where segment replication feature is not available", UPGRADE_FROM_VERSION);
+            return;
+        }
+        Nodes nodes = buildNodeAndVersions();
+        assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
+        logger.info("cluster discovered:\n {}", nodes.toString());
+        final List<String> bwcNamesList = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.toList());
+        final String bwcNames = bwcNamesList.stream().collect(Collectors.joining(","));
+        // Update allocation settings so that primaries gets allocated only on nodes running on older version
+        Settings.Builder settings = Settings.builder()
+            .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+            .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .putList("index.sort.field", "sortfield")
+            .put("index.routing.allocation.include._name", bwcNames);
+        final String index = "test-index";
+        createIndex(index, settings.build(), TEST_MAPPING);
+        ensureNoInitializingShards(); // wait for all other shard activity to finish
+
+        int docCount = 200;
+        try (RestClient nodeClient = buildClient(restClientSettings(),
+            nodes.getNewNodes().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
+
+            logger.info("Remove allocation include settings so that shards can be allocated on current version nodes");
+            updateIndexSettings(index, Settings.builder().putNull("index.routing.allocation.include._name"));
+            // Add replicas so that it can be assigned on higher OS version nodes.
+            updateIndexSettings(index, Settings.builder().put("index.number_of_replicas", 2));
+
+            printClusterRouting();
+            ensureGreen(index);
+
+            // Index docs
+            indexDocs(index, 0, docCount);
+
+            // perform a refresh
+            assertOK(client().performRequest(new Request("POST", index + "/_flush")));
+
+            // verify replica catch up with primary
+            assertSeqNoOnShards(index, nodes, docCount, nodeClient);
+        }
+    }
+
+
+    /**
+     * This test creates a cluster with primary on higher version but due to {@link org.opensearch.cluster.routing.allocation.decider.NodeVersionAllocationDecider};
+     * replica shard allocation on lower OpenSearch version is prevented. Thus, this test though cover the use case where
+     * primary shard containing nodes are running on higher OS version while replicas are unassigned.
+     *
+     * @throws Exception
+     */
+    public void testIndexingWithReplicaOnBwcNodes() throws Exception {
+        if (UPGRADE_FROM_VERSION.before(Version.V_2_4_0)) {
+            logger.info("--> Skip test for version {} where segment replication feature is not available", UPGRADE_FROM_VERSION);
+            return;
+        }
+        Nodes nodes = buildNodeAndVersions();
+        assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
+        logger.info("cluster discovered:\n {}", nodes.toString());
+        final List<String> bwcNamesList = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.toList());
+        final String bwcNames = bwcNamesList.stream().collect(Collectors.joining(","));
+        // Exclude bwc nodes from allocation so that primaries gets allocated on current/higher version
+        Settings.Builder settings = Settings.builder()
+            .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+            .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .putList("index.sort.field", "sortfield")
+            .put("index.routing.allocation.exclude._name", bwcNames);
+        final String index = "test-index";
+        createIndex(index, settings.build(), TEST_MAPPING);
+        ensureNoInitializingShards(); // wait for all other shard activity to finish
+        printClusterRouting();
+
+        int docCount = 200;
+        try (RestClient nodeClient = buildClient(restClientSettings(),
+            nodes.values().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
+
+            logger.info("allowing replica shards assignment on bwc nodes");
+            updateIndexSettings(index, Settings.builder().putNull("index.routing.allocation.exclude._name"));
+            // Add replicas so that it can be assigned on lower OS version nodes, but it doesn't work as called out in test overview
+            updateIndexSettings(index, Settings.builder().put("index.number_of_replicas", 2));
+            printClusterRouting();
+
+            // Index docs
+            indexDocs(index, 0, docCount);
+
+            // perform a refresh
+            assertOK(client().performRequest(new Request("POST", index + "/_flush")));
+
+            // verify replica catch up with primary
+            assertSeqNoOnShards(index, nodes, docCount, nodeClient);
+        }
+    }
+
     public void testIndexVersionPropagation() throws Exception {
         Nodes nodes = buildNodeAndVersions();
         assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
@@ -106,11 +222,12 @@ public void testIndexVersionPropagation() throws Exception {
         Settings.Builder settings = Settings.builder()
                 .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                 .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 2)
+                .putList("index.sort.field", "sortfield")
                 .put("index.routing.allocation.include._name", bwcNames);
         final String index = "indexversionprop";
         final int minUpdates = 5;
         final int maxUpdates = 10;
-        createIndex(index, settings.build());
+        createIndex(index, settings.build(), TEST_MAPPING);
         try (RestClient newNodeClient = buildClient(restClientSettings(),
                 nodes.getNewNodes().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
 
@@ -192,10 +309,11 @@ public void testSeqNoCheckpoints() throws Exception {
         Settings.Builder settings = Settings.builder()
             .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
             .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 2)
+            .putList("index.sort.field", "sortfield")
             .put("index.routing.allocation.include._name", bwcNames);
 
         final String index = "test";
-        createIndex(index, settings.build());
+        createIndex(index, settings.build(), TEST_MAPPING);
         try (RestClient newNodeClient = buildClient(restClientSettings(),
             nodes.getNewNodes().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
             int numDocs = 0;
@@ -257,15 +375,14 @@ public void testUpdateSnapshotStatus() throws Exception {
 
         // Create the repository before taking the snapshot.
         Request request = new Request("PUT", "/_snapshot/repo");
-        request.setJsonEntity(Strings
-            .toString(JsonXContent.contentBuilder()
+        request.setJsonEntity(JsonXContent.contentBuilder()
                 .startObject()
                     .field("type", "fs")
                     .startObject("settings")
                         .field("compress", randomBoolean())
                         .field("location", System.getProperty("tests.path.repo"))
                     .endObject()
-                .endObject()));
+                .endObject().toString());
 
         assertOK(client().performRequest(request));
 
@@ -275,10 +392,11 @@ public void testUpdateSnapshotStatus() throws Exception {
         Settings.Builder settings = Settings.builder()
             .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), between(5, 10))
             .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
+            .putList("index.sort.field", "sortfield")
             .put("index.routing.allocation.include._name", bwcNames);
 
         final String index = "test-snapshot-index";
-        createIndex(index, settings.build());
+        createIndex(index, settings.build(), TEST_MAPPING);
         indexDocs(index, 0, between(50, 100));
         ensureGreen(index);
         assertOK(client().performRequest(new Request("POST", index + "/_refresh")));
@@ -312,7 +430,8 @@ public void testSyncedFlushTransition() throws Exception {
         createIndex(index, Settings.builder()
             .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), numShards)
             .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numOfReplicas)
-            .put("index.routing.allocation.include._name", newNodes).build());
+            .putList("index.sort.field", "sortfield")
+            .put("index.routing.allocation.include._name", newNodes).build(), TEST_MAPPING);
         ensureGreen(index);
         indexDocs(index, randomIntBetween(0, 100), between(1, 100));
         try (RestClient oldNodeClient = buildClient(restClientSettings(),
@@ -322,7 +441,7 @@ public void testSyncedFlushTransition() throws Exception {
                 ResponseException responseException = expectThrows(ResponseException.class, () -> oldNodeClient.performRequest(request));
                 assertThat(responseException.getResponse().getStatusLine().getStatusCode(), equalTo(RestStatus.CONFLICT.getStatus()));
                 assertThat(responseException.getResponse().getWarnings(),
-                    contains("Synced flush is deprecated and will be removed in 8.0. Use flush at _/flush or /{index}/_flush instead."));
+                    contains("Synced flush is deprecated and will be removed in 3.0. Use flush at _/flush or /{index}/_flush instead."));
                 Map<String, Object> result = ObjectPath.createFromResponse(responseException.getResponse()).evaluate("_shards");
                 assertThat(result.get("total"), equalTo(totalShards));
                 assertThat(result.get("successful"), equalTo(0));
@@ -429,23 +548,23 @@ private Nodes buildNodeAndVersions() throws IOException {
                 HttpHost.create(objectPath.evaluate("nodes." + id + ".http.publish_address"))));
         }
         response = client().performRequest(new Request("GET", "_cluster/state"));
-        nodes.setMasterNodeId(ObjectPath.createFromResponse(response).evaluate("master_node"));
+        nodes.setClusterManagerNodeId(ObjectPath.createFromResponse(response).evaluate("master_node"));
         return nodes;
     }
 
     final class Nodes extends HashMap<String, Node> {
 
-        private String masterNodeId = null;
+        private String clusterManagerNodeId = null;
 
-        public Node getMaster() {
-            return get(masterNodeId);
+        public Node getClusterManager() {
+            return get(clusterManagerNodeId);
         }
 
-        public void setMasterNodeId(String id) {
+        public void setClusterManagerNodeId(String id) {
             if (get(id) == null) {
                 throw new IllegalArgumentException("node with id [" + id + "] not found. got:" + toString());
             }
-            masterNodeId = id;
+            clusterManagerNodeId = id;
         }
 
         public void add(Node node) {
@@ -480,7 +599,7 @@ public Node getSafe(String id) {
         @Override
         public String toString() {
             return "Nodes{" +
-                "masterNodeId='" + masterNodeId + "'\n" +
+                "masterNodeId='" + clusterManagerNodeId + "'\n" +
                 values().stream().map(Node::toString).collect(Collectors.joining("\n")) +
                 '}';
         }
@@ -557,4 +676,15 @@ public String toString() {
                 '}';
         }
     }
+
+    private static String createTestMapping() {
+        return "  \"properties\": {\n"
+            + "    \"test\": {\n"
+            + "      \"type\": \"text\"\n"
+            + "    },\n"
+            + "    \"sortfield\": {\n"
+            + "      \"type\": \"integer\"\n"
+            + "    }\n"
+            + "  }";
+    }
 }
diff --git a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/SearchingIT.java b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/SearchingIT.java
new file mode 100644
index 0000000000000..7d427da9b6559
--- /dev/null
+++ b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/SearchingIT.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.backwards;
+
+import org.apache.http.HttpHost;
+import org.opensearch.action.get.MultiGetRequest;
+import org.opensearch.action.get.MultiGetResponse;
+import org.opensearch.client.Request;
+import org.opensearch.client.RequestOptions;
+import org.opensearch.client.Response;
+import org.opensearch.client.RestClient;
+import org.opensearch.client.RestHighLevelClient;
+import org.opensearch.test.rest.OpenSearchRestTestCase;
+import org.opensearch.test.rest.yaml.ObjectPath;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import static org.hamcrest.Matchers.containsString;
+
+public class SearchingIT extends OpenSearchRestTestCase {
+    public void testMultiGet() throws Exception {
+        final Set<HttpHost> nodes = buildNodes();
+
+        final MultiGetRequest multiGetRequest = new MultiGetRequest();
+        multiGetRequest.add("index", "id1");
+
+        try (RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(nodes.toArray(HttpHost[]::new)))) {
+            MultiGetResponse response = client.mget(multiGetRequest, RequestOptions.DEFAULT);
+            assertEquals(1, response.getResponses().length);
+
+            assertTrue(response.getResponses()[0].isFailed());
+            assertNotNull(response.getResponses()[0].getFailure());
+            assertEquals(response.getResponses()[0].getFailure().getId(), "id1");
+            assertEquals(response.getResponses()[0].getFailure().getIndex(), "index");
+            assertThat(response.getResponses()[0].getFailure().getMessage(), containsString("no such index [index]"));
+       }
+    }
+
+    private Set<HttpHost> buildNodes() throws IOException, URISyntaxException {
+        Response response = client().performRequest(new Request("GET", "_nodes"));
+        ObjectPath objectPath = ObjectPath.createFromResponse(response);
+        Map<String, Object> nodesAsMap = objectPath.evaluate("nodes");
+        final Set<HttpHost> nodes = new HashSet<>();
+        for (String id : nodesAsMap.keySet()) {
+            nodes.add(HttpHost.create((String) objectPath.evaluate("nodes." + id + ".http.publish_address")));
+        }
+
+        return nodes;
+    }
+}
diff --git a/qa/multi-cluster-search/build.gradle b/qa/multi-cluster-search/build.gradle
index 64aabf602e501..907791bd6a7de 100644
--- a/qa/multi-cluster-search/build.gradle
+++ b/qa/multi-cluster-search/build.gradle
@@ -45,7 +45,7 @@ task 'remote-cluster'(type: RestIntegTestTask) {
 
 testClusters.'remote-cluster' {
   numberOfNodes = 2
-  setting 'node.roles', '[data,ingest,master]'
+  setting 'node.roles', '[data,ingest,cluster_manager]'
 }
 
 task mixedClusterTest(type: RestIntegTestTask) {
diff --git a/qa/multi-cluster-search/src/test/java/org/opensearch/search/CCSDuelIT.java b/qa/multi-cluster-search/src/test/java/org/opensearch/search/CCSDuelIT.java
index 9913e5816e856..3dc2444d8a16e 100644
--- a/qa/multi-cluster-search/src/test/java/org/opensearch/search/CCSDuelIT.java
+++ b/qa/multi-cluster-search/src/test/java/org/opensearch/search/CCSDuelIT.java
@@ -36,7 +36,7 @@
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.tests.util.TimeUnits;
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
@@ -53,12 +53,12 @@
 import org.opensearch.client.RestHighLevelClient;
 import org.opensearch.client.indices.CreateIndexRequest;
 import org.opensearch.client.indices.CreateIndexResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -198,7 +198,7 @@ private static void indexDocuments(String idPrefix) throws IOException, Interrup
         createIndexRequest.mapping("{\"properties\":{" +
                 "\"id\":{\"type\":\"keyword\"}," +
                 "\"suggest\":{\"type\":\"completion\"}," +
-                "\"join\":{\"type\":\"join\", \"relations\": {\"question\":\"answer\"}}}}", XContentType.JSON);
+                "\"join\":{\"type\":\"join\", \"relations\": {\"question\":\"answer\"}}}}", MediaTypeRegistry.JSON);
         CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);
         assertTrue(createIndexResponse.isAcknowledged());
 
@@ -255,7 +255,7 @@ private static IndexRequest buildIndexRequest(String id, String type, String que
         if (questionId != null) {
             joinField.put("parent", questionId);
         }
-        indexRequest.source(XContentType.JSON,
+        indexRequest.source(MediaTypeRegistry.JSON,
             "id", id,
             "type", type,
             "votes", randomIntBetween(0, 30),
@@ -726,7 +726,7 @@ public void testCompletionSuggester() throws Exception {
         sourceBuilder.suggest(suggestBuilder);
         duelSearch(searchRequest, response -> {
             assertMultiClusterSearchResponse(response);
-            assertEquals(Strings.toString(response, true, true), 3, response.getSuggest().size());
+            assertEquals(Strings.toString(MediaTypeRegistry.JSON, response, true, true), 3, response.getSuggest().size());
             assertThat(response.getSuggest().getSuggestion("python").getEntries().size(), greaterThan(0));
             assertThat(response.getSuggest().getSuggestion("java").getEntries().size(), greaterThan(0));
             assertThat(response.getSuggest().getSuggestion("ruby").getEntries().size(), greaterThan(0));
@@ -827,8 +827,8 @@ private static void assertAggs(SearchResponse response) {
 
     @SuppressWarnings("unchecked")
     private static Map<String, Object> responseToMap(SearchResponse response) throws IOException {
-        BytesReference bytesReference = XContentHelper.toXContent(response, XContentType.JSON, false);
-        Map<String, Object> responseMap = XContentHelper.convertToMap(bytesReference, false, XContentType.JSON).v2();
+        BytesReference bytesReference = XContentHelper.toXContent(response, MediaTypeRegistry.JSON, false);
+        Map<String, Object> responseMap = org.opensearch.common.xcontent.XContentHelper.convertToMap(bytesReference, false, MediaTypeRegistry.JSON).v2();
         assertNotNull(responseMap.put("took", -1));
         responseMap.remove("num_reduce_phases");
         Map<String, Object> profile = (Map<String, Object>)responseMap.get("profile");
diff --git a/qa/multi-cluster-search/src/test/resources/rest-api-spec/test/multi_cluster/70_skip_shards.yml b/qa/multi-cluster-search/src/test/resources/rest-api-spec/test/multi_cluster/70_skip_shards.yml
index 92ae11c712b25..23cd1567b49ba 100644
--- a/qa/multi-cluster-search/src/test/resources/rest-api-spec/test/multi_cluster/70_skip_shards.yml
+++ b/qa/multi-cluster-search/src/test/resources/rest-api-spec/test/multi_cluster/70_skip_shards.yml
@@ -220,4 +220,3 @@
     # When all shards are skipped current logic returns 1 to produce a valid search result
   - match: { _shards.skipped : 1}
   - match: { _shards.failed: 0 }
-
diff --git a/qa/os/build.gradle b/qa/os/build.gradle
index 038e3d16745c3..66c6525439dac 100644
--- a/qa/os/build.gradle
+++ b/qa/os/build.gradle
@@ -42,15 +42,17 @@ dependencies {
   api "org.apache.httpcomponents:fluent-hc:${versions.httpclient}"
   api "org.apache.logging.log4j:log4j-api:${versions.log4j}"
   api "org.apache.logging.log4j:log4j-core:${versions.log4j}"
+  api "org.apache.logging.log4j:log4j-jul:${versions.log4j}"
   api "org.apache.logging.log4j:log4j-jcl:${versions.log4j}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
   api "commons-logging:commons-logging:${versions.commonslogging}"
 
+  api project(':libs:opensearch-common')
   api project(':libs:opensearch-core')
 
   testImplementation "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
   testImplementation "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
-  testImplementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
+  testImplementation "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
 }
 
 tasks.named('forbiddenApisTest').configure {
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/ArchiveTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/ArchiveTests.java
index 898ea12b6a6c3..29e40a4e179cb 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/ArchiveTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/ArchiveTests.java
@@ -328,7 +328,7 @@ public void test54ForceBundledJdkEmptyJavaHome() throws Exception {
     public void test70CustomPathConfAndJvmOptions() throws Exception {
 
         withCustomConfig(tempConf -> {
-            final List<String> jvmOptions = org.opensearch.common.collect.List.of("-Xms512m", "-Xmx512m", "-Dlog4j2.disable.jmx=true");
+            final List<String> jvmOptions = List.of("-Xms512m", "-Xmx512m", "-Dlog4j2.disable.jmx=true");
             Files.write(tempConf.resolve("jvm.options"), jvmOptions, CREATE, APPEND);
 
             sh.getEnv().put("OPENSEARCH_JAVA_OPTS", "-XX:-UseCompressedOops");
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/DebMetadataTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/DebMetadataTests.java
index 299f23e83db41..0db5aec7b1d0e 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/DebMetadataTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/DebMetadataTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.packaging.test;
 
-import junit.framework.TestCase;
 import org.opensearch.packaging.util.Distribution;
 import org.opensearch.packaging.util.FileUtils;
 import org.opensearch.packaging.util.Shell;
@@ -40,6 +39,8 @@
 
 import java.util.regex.Pattern;
 
+import junit.framework.TestCase;
+
 import static org.opensearch.packaging.util.FileUtils.getDistributionFile;
 import static org.junit.Assume.assumeTrue;
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/DockerTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/DockerTests.java
index 725e430b3634c..be9741e660223 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/DockerTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/DockerTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.packaging.test;
 
 import com.fasterxml.jackson.databind.JsonNode;
+
 import org.opensearch.packaging.util.Installation;
 import org.opensearch.packaging.util.Platforms;
 import org.opensearch.packaging.util.ServerUtils;
@@ -43,9 +44,13 @@
 import org.junit.BeforeClass;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -85,11 +90,6 @@
 import static org.junit.Assume.assumeFalse;
 import static org.junit.Assume.assumeTrue;
 
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Paths;
-import java.util.Arrays;
-import java.util.HashSet;
-
 public class DockerTests extends PackagingTestCase {
     private Path tempDir;
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/KeystoreManagementTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/KeystoreManagementTests.java
index fee3b0bc501d9..4970a874ffb1a 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/KeystoreManagementTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/KeystoreManagementTests.java
@@ -52,7 +52,6 @@
 import java.util.List;
 import java.util.Map;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.randomBoolean;
 import static java.util.Collections.singletonList;
 import static org.opensearch.packaging.util.Archives.ARCHIVE_OWNER;
 import static org.opensearch.packaging.util.Archives.installArchive;
@@ -76,6 +75,7 @@
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.startsWith;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.randomBoolean;
 import static org.junit.Assume.assumeThat;
 import static org.junit.Assume.assumeTrue;
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/PackagingTestCase.java b/qa/os/src/test/java/org/opensearch/packaging/test/PackagingTestCase.java
index 259ae6e766c8e..02a613be320c2 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/PackagingTestCase.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/PackagingTestCase.java
@@ -39,10 +39,11 @@
 import com.carrotsearch.randomizedtesting.annotations.TestGroup;
 import com.carrotsearch.randomizedtesting.annotations.TestMethodProviders;
 import com.carrotsearch.randomizedtesting.annotations.Timeout;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.packaging.util.Archives;
 import org.opensearch.packaging.util.Distribution;
 import org.opensearch.packaging.util.Docker;
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/RpmMetadataTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/RpmMetadataTests.java
index 5eb8ffe8817ee..f95a79efa51ef 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/RpmMetadataTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/RpmMetadataTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.packaging.test;
 
-import junit.framework.TestCase;
 import org.opensearch.packaging.util.Distribution;
 import org.opensearch.packaging.util.Platforms;
 import org.opensearch.packaging.util.Shell;
@@ -40,6 +39,8 @@
 
 import java.util.regex.Pattern;
 
+import junit.framework.TestCase;
+
 import static org.opensearch.packaging.util.FileUtils.getDistributionFile;
 import static org.junit.Assume.assumeTrue;
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/test/WindowsServiceTests.java b/qa/os/src/test/java/org/opensearch/packaging/test/WindowsServiceTests.java
index 57ea853e735a9..f4bb9d70354a0 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/test/WindowsServiceTests.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/test/WindowsServiceTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.packaging.test;
 
-import junit.framework.TestCase;
 import org.opensearch.packaging.util.FileUtils;
 import org.opensearch.packaging.util.Platforms;
 import org.opensearch.packaging.util.ServerUtils;
@@ -46,13 +45,15 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.assumeTrue;
+import junit.framework.TestCase;
+
 import static org.opensearch.packaging.util.Archives.installArchive;
 import static org.opensearch.packaging.util.Archives.verifyArchiveInstallation;
 import static org.opensearch.packaging.util.FileUtils.append;
 import static org.opensearch.packaging.util.FileUtils.mv;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.equalTo;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.assumeTrue;
 
 public class WindowsServiceTests extends PackagingTestCase {
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/util/Docker.java b/qa/os/src/test/java/org/opensearch/packaging/util/Docker.java
index ef5b1e590635a..6517062c0ca50 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/util/Docker.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/util/Docker.java
@@ -34,6 +34,7 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.client.fluent.Request;
diff --git a/qa/os/src/test/java/org/opensearch/packaging/util/FileUtils.java b/qa/os/src/test/java/org/opensearch/packaging/util/FileUtils.java
index aa52c3325bee5..5169ce18fff79 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/util/FileUtils.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/util/FileUtils.java
@@ -33,7 +33,7 @@
 package org.opensearch.packaging.util;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.hamcrest.FeatureMatcher;
 import org.hamcrest.Matcher;
 
@@ -83,7 +83,7 @@ public class FileUtils {
     public static List<Path> lsGlob(Path directory, String glob) {
         List<Path> paths = new ArrayList<>();
         if (Files.exists(directory) == false) {
-            return org.opensearch.common.collect.List.of();
+            return List.of();
         }
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(directory, glob)) {
 
diff --git a/qa/os/src/test/java/org/opensearch/packaging/util/Packages.java b/qa/os/src/test/java/org/opensearch/packaging/util/Packages.java
index cea03a0b6fe70..e9ebf28042b46 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/util/Packages.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/util/Packages.java
@@ -194,11 +194,11 @@ private static void verifyInstallation(Installation opensearch, Distribution dis
 
         // we shell out here because java's posix file permission view doesn't support special modes
         assertThat(opensearch.config, file(Directory, "root", "opensearch", p750));
-        assertThat(sh.run("find \"" + opensearch.config + "\" -maxdepth 0 -printf \"%m\"").stdout, containsString("2750"));
+        assertThat(sh.run("find \"" + opensearch.config + "\" -maxdepth 0 -printf \"%m\"").stdout, containsString("750"));
 
         final Path jvmOptionsDirectory = opensearch.config.resolve("jvm.options.d");
         assertThat(jvmOptionsDirectory, file(Directory, "root", "opensearch", p750));
-        assertThat(sh.run("find \"" + jvmOptionsDirectory + "\" -maxdepth 0 -printf \"%m\"").stdout, containsString("2750"));
+        assertThat(sh.run("find \"" + jvmOptionsDirectory + "\" -maxdepth 0 -printf \"%m\"").stdout, containsString("750"));
 
         Stream.of("opensearch.keystore", "opensearch.yml", "jvm.options", "log4j2.properties")
             .forEach(configFile -> assertThat(opensearch.config(configFile), file(File, "root", "opensearch", p660)));
@@ -322,7 +322,7 @@ private enum PackageManagerCommand {
         REMOVE
     }
 
-    private static Map<PackageManagerCommand, String> RPM_OPTIONS = org.opensearch.common.collect.Map.of(
+    private static Map<PackageManagerCommand, String> RPM_OPTIONS = Map.of(
         PackageManagerCommand.QUERY,
         "-qe",
         PackageManagerCommand.INSTALL,
@@ -335,7 +335,7 @@ private enum PackageManagerCommand {
         "-e"
     );
 
-    private static Map<PackageManagerCommand, String> DEB_OPTIONS = org.opensearch.common.collect.Map.of(
+    private static Map<PackageManagerCommand, String> DEB_OPTIONS = Map.of(
         PackageManagerCommand.QUERY,
         "-s",
         PackageManagerCommand.INSTALL,
diff --git a/qa/os/src/test/java/org/opensearch/packaging/util/ServerUtils.java b/qa/os/src/test/java/org/opensearch/packaging/util/ServerUtils.java
index d92feec21daaf..42eac9fdf4961 100644
--- a/qa/os/src/test/java/org/opensearch/packaging/util/ServerUtils.java
+++ b/qa/os/src/test/java/org/opensearch/packaging/util/ServerUtils.java
@@ -52,6 +52,7 @@
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.TrustManagerFactory;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
diff --git a/qa/remote-clusters/docker-test-entrypoint.sh b/qa/remote-clusters/docker-test-entrypoint.sh
index e08e388b8c98d..18a9363d375ab 100755
--- a/qa/remote-clusters/docker-test-entrypoint.sh
+++ b/qa/remote-clusters/docker-test-entrypoint.sh
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+set -e -o pipefail 
+
 cd /usr/share/opensearch/bin/
 ./opensearch-users useradd rest_user -p test-password -r superuser || true
 echo "testnode" > /tmp/password
diff --git a/qa/remote-clusters/src/test/java/org/opensearch/cluster/remote/test/AbstractMultiClusterRemoteTestCase.java b/qa/remote-clusters/src/test/java/org/opensearch/cluster/remote/test/AbstractMultiClusterRemoteTestCase.java
index 61ccbab95850d..4238219f2c0ed 100644
--- a/qa/remote-clusters/src/test/java/org/opensearch/cluster/remote/test/AbstractMultiClusterRemoteTestCase.java
+++ b/qa/remote-clusters/src/test/java/org/opensearch/cluster/remote/test/AbstractMultiClusterRemoteTestCase.java
@@ -39,7 +39,7 @@
 import org.opensearch.client.RestClient;
 import org.opensearch.client.RestHighLevelClient;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 
 import java.io.IOException;
diff --git a/qa/repository-multi-version/src/test/java/org/opensearch/upgrades/MultiVersionRepositoryAccessIT.java b/qa/repository-multi-version/src/test/java/org/opensearch/upgrades/MultiVersionRepositoryAccessIT.java
index c0b90626d7bad..7a32b92d8aa75 100644
--- a/qa/repository-multi-version/src/test/java/org/opensearch/upgrades/MultiVersionRepositoryAccessIT.java
+++ b/qa/repository-multi-version/src/test/java/org/opensearch/upgrades/MultiVersionRepositoryAccessIT.java
@@ -46,8 +46,8 @@
 import org.opensearch.client.RestClient;
 import org.opensearch.client.RestHighLevelClient;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
diff --git a/qa/rolling-upgrade/build.gradle b/qa/rolling-upgrade/build.gradle
index 3dff452be855f..68a9dcafbdc47 100644
--- a/qa/rolling-upgrade/build.gradle
+++ b/qa/rolling-upgrade/build.gradle
@@ -74,6 +74,7 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
     }
     systemProperty 'tests.upgrade_from_version', bwcVersionStr
     systemProperty 'tests.rest.suite', 'old_cluster'
+    systemProperty 'tests.repo_location', "${buildDir}/cluster/shared/repo/${baseName}/test"
     nonInputProperties.systemProperty('tests.rest.cluster', "${-> testClusters."${baseName}".allHttpSocketURI.join(",")}")
     nonInputProperties.systemProperty('tests.clustername', "${-> testClusters."${baseName}".getName()}")
   }
@@ -110,6 +111,7 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
       testClusters."${baseName}".nextNodeToNextVersion()
     }
     useCluster testClusters."${baseName}"
+    systemProperty 'tests.repo_location', "${buildDir}/cluster/shared/repo/${baseName}/test"
     systemProperty 'tests.rest.suite', 'upgraded_cluster'
     systemProperty 'tests.upgrade_from_version', bwcVersionStr
 
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/AbstractRollingTestCase.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/AbstractRollingTestCase.java
index 27766e4086b91..ee1c1fd888438 100644
--- a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/AbstractRollingTestCase.java
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/AbstractRollingTestCase.java
@@ -56,6 +56,7 @@ public static ClusterType parse(String value) {
     }
 
     protected static final ClusterType CLUSTER_TYPE = ClusterType.parse(System.getProperty("tests.rest.suite"));
+    protected static final String REPOSITORY_LOCATION = System.getProperty("tests.repo_location");
     protected static final Version UPGRADE_FROM_VERSION = Version.fromString(System.getProperty("tests.upgrade_from_version"));
     protected static final boolean firstMixedRound = Boolean.parseBoolean(System.getProperty("tests.first_round", "false"));
 
@@ -74,6 +75,9 @@ protected boolean preserveTemplatesUponCompletion() {
         return true;
     }
 
+    @Override
+    protected final boolean preserveSnapshotsUponCompletion() { return true; }
+
     @Override
     protected final Settings restClientSettings() {
         return Settings.builder().put(super.restClientSettings())
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/IndexingIT.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/IndexingIT.java
index f34e5f7bc121a..3f341537ee934 100644
--- a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/IndexingIT.java
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/IndexingIT.java
@@ -32,6 +32,8 @@
 package org.opensearch.upgrades;
 
 import org.apache.http.util.EntityUtils;
+import org.apache.http.ParseException;
+
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.client.Request;
@@ -39,16 +41,26 @@
 import org.opensearch.client.ResponseException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Booleans;
+import org.opensearch.common.io.Streams;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.action.document.RestBulkAction;
+import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.engine.EngineConfig;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.rest.yaml.ObjectPath;
 
 import java.io.IOException;
+import java.net.URISyntaxException;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 
+import static org.opensearch.cluster.routing.UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING;
 import static org.opensearch.rest.action.search.RestSearchAction.TOTAL_HITS_AS_INT_PARAM;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.either;
+import static org.opensearch.test.OpenSearchIntegTestCase.CODECS;
 
 /**
  * Basic test that indexed documents survive the rolling restart. See
@@ -61,7 +73,106 @@
  */
 public class IndexingIT extends AbstractRollingTestCase {
 
-    public void testIndexing() throws IOException {
+    private void printClusterNodes() throws IOException, ParseException, URISyntaxException {
+        Request clusterStateRequest = new Request("GET", "_nodes");
+        Response response = client().performRequest(clusterStateRequest);
+
+        ObjectPath objectPath = ObjectPath.createFromResponse(response);
+        Map<String, Object> nodesAsMap = objectPath.evaluate("nodes");
+        for (String id : nodesAsMap.keySet()) {
+            logger.info("--> {} {} {}",
+                id,
+                objectPath.evaluate("nodes." + id + ".name"),
+                Version.fromString(objectPath.evaluate("nodes." + id + ".version")));
+        }
+        response = client().performRequest(new Request("GET", "_cluster/state"));
+        String cm = ObjectPath.createFromResponse(response).evaluate("master_node");
+        logger.info("--> Cluster manager {}", cm);
+    }
+
+    // Verifies that for each shard copy holds same document count across all containing nodes.
+    private void waitForSearchableDocs(String index, int shardCount, int replicaCount) throws Exception {
+        assertTrue(shardCount > 0);
+        assertTrue(replicaCount > 0);
+        waitForClusterHealthWithNoShardMigration(index, "green");
+        logger.info("--> _cat/shards before search \n{}", EntityUtils.toString(client().performRequest(new Request("GET", "/_cat/shards?v")).getEntity()));
+
+        // Verify segment replication stats
+        verifySegmentStats(index);
+
+        // Verify segment store
+        assertBusy(() -> {
+            /**
+             * Use default tabular output and sort response based on shard,segment,primaryOrReplica columns to allow line by
+             * line parsing where records related to a segment (e.g. _0) are chunked together with first record belonging
+             * to primary while remaining *replicaCount* records belongs to replica copies
+             * */
+            Request segrepStatsRequest = new Request("GET", "/_cat/segments/" + index + "?s=shard,segment,primaryOrReplica");
+            segrepStatsRequest.addParameter("h", "index,shard,primaryOrReplica,segment,docs.count");
+            Response segrepStatsResponse = client().performRequest(segrepStatsRequest);
+            List<String> responseList = Streams.readAllLines(segrepStatsResponse.getEntity().getContent());
+            logger.info("--> _cat/segments response\n {}", responseList.toString().replace(',', '\n'));
+            // Filter response for rows with zero doc count
+            List<String> filteredList = new ArrayList<>();
+            for(String row: responseList) {
+                String count = row.split(" +")[4];
+                if (count.equals("0") == false) {
+                    filteredList.add(row);
+                }
+            }
+            // Ensure there is result for replica copies before processing the result. This results in retry when there
+            // are not enough number of rows vs failing with IndexOutOfBoundsException
+            assertEquals(0, filteredList.size() % (replicaCount + 1));
+            for (int segmentsIndex=0; segmentsIndex < filteredList.size();) {
+                String[] primaryRow = filteredList.get(segmentsIndex++).split(" +");
+                String shardId = primaryRow[0] + primaryRow[1];
+                assertTrue(primaryRow[2].equals("p"));
+                for(int replicaIndex = 1; replicaIndex <= replicaCount; replicaIndex++) {
+                    String[] replicaRow = filteredList.get(segmentsIndex).split(" +");
+                    String replicaShardId = replicaRow[0] + replicaRow[1];
+                    // When segment has 0 doc count, not all replica copies posses that segment. Skip to next segment
+                    if (replicaRow[2].equals("p")) {
+                        assertTrue(primaryRow[4].equals("0"));
+                        break;
+                    }
+                    // verify same shard id
+                    assertTrue(replicaShardId.equals(shardId));
+                    // verify replica row
+                    assertTrue(replicaRow[2].equals("r"));
+                    // Verify segment name matches e.g. _0
+                    assertTrue(replicaRow[3].equals(primaryRow[3]));
+                    // Verify doc count matches
+                    assertTrue(replicaRow[4].equals(primaryRow[4]));
+                    segmentsIndex++;
+                }
+            }
+        }, 1, TimeUnit.MINUTES);
+    }
+
+    private void waitForClusterHealthWithNoShardMigration(String indexName, String status) throws IOException {
+        Request waitForStatus = new Request("GET", "/_cluster/health/" + indexName);
+        waitForStatus.addParameter("wait_for_status", status);
+        // wait for long enough that we give delayed unassigned shards to stop being delayed
+        waitForStatus.addParameter("timeout", "70s");
+        waitForStatus.addParameter("level", "shards");
+        waitForStatus.addParameter("wait_for_no_initializing_shards", "true");
+        waitForStatus.addParameter("wait_for_no_relocating_shards", "true");
+        client().performRequest(waitForStatus);
+    }
+
+    private void verifySegmentStats(String indexName) throws Exception {
+        assertBusy(() -> {
+            Request segrepStatsRequest = new Request("GET", "/_cat/segment_replication/" + indexName);
+            segrepStatsRequest.addParameter("h", "shardId,target_node,checkpoints_behind");
+            Response segrepStatsResponse = client().performRequest(segrepStatsRequest);
+            for (String statLine : Streams.readAllLines(segrepStatsResponse.getEntity().getContent())) {
+                String[] elements = statLine.split(" +");
+                assertEquals("Replica shard " + elements[0] + "not upto date with primary ", 0, Integer.parseInt(elements[2]));
+            }
+        }, 1, TimeUnit.MINUTES);
+    }
+
+    public void testIndexing() throws Exception {
         switch (CLUSTER_TYPE) {
         case OLD:
             break;
@@ -147,6 +258,96 @@ public void testIndexing() throws IOException {
         }
     }
 
+
+    /**
+     * This test verifies that during rolling upgrades the segment replication does not break when replica shards can
+     * be running on older codec versions.
+     *
+     * @throws Exception
+     */
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/7679")
+    public void testIndexingWithSegRep() throws Exception {
+        if (UPGRADE_FROM_VERSION.before(Version.V_2_4_0)) {
+            logger.info("--> Skip test for version {} where segment replication feature is not available", UPGRADE_FROM_VERSION);
+            return;
+        }
+        final String indexName = "test-index-segrep";
+        final int shardCount = 3;
+        final int replicaCount = 2;
+        logger.info("--> Case {}", CLUSTER_TYPE);
+        printClusterNodes();
+        logger.info("--> _cat/shards before test execution \n{}", EntityUtils.toString(client().performRequest(new Request("GET", "/_cat/shards?v")).getEntity()));
+        switch (CLUSTER_TYPE) {
+            case OLD:
+                Settings.Builder settings = Settings.builder()
+                    .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), shardCount)
+                    .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), replicaCount)
+                    .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                    .put(
+                        EngineConfig.INDEX_CODEC_SETTING.getKey(),
+                        randomFrom(new ArrayList<>(CODECS) {
+                            {
+                                add(CodecService.LUCENE_DEFAULT_CODEC);
+                            }
+                        })
+                    )
+                    .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms");
+                createIndex(indexName, settings.build());
+                waitForClusterHealthWithNoShardMigration(indexName, "green");
+                bulk(indexName, "_OLD", 5);
+                break;
+            case MIXED:
+                waitForClusterHealthWithNoShardMigration(indexName, "yellow");
+                break;
+            case UPGRADED:
+                waitForClusterHealthWithNoShardMigration(indexName, "green");
+                break;
+            default:
+                throw new UnsupportedOperationException("Unknown cluster type [" + CLUSTER_TYPE + "]");
+        }
+
+        int expectedCount;
+        switch (CLUSTER_TYPE) {
+            case OLD:
+                expectedCount = 5;
+                break;
+            case MIXED:
+                if (Booleans.parseBoolean(System.getProperty("tests.first_round"))) {
+                    expectedCount = 5;
+                } else {
+                    expectedCount = 10;
+                }
+                break;
+            case UPGRADED:
+                expectedCount = 15;
+                break;
+            default:
+                throw new UnsupportedOperationException("Unknown cluster type [" + CLUSTER_TYPE + "]");
+        }
+
+        waitForSearchableDocs(indexName, shardCount, replicaCount);
+        assertCount(indexName, expectedCount);
+
+        if (CLUSTER_TYPE != ClusterType.OLD) {
+            logger.info("--> Bulk index 5 documents");
+            bulk(indexName, "_" + CLUSTER_TYPE, 5);
+            logger.info("--> Index one doc (to be deleted next) and verify doc count");
+            Request toBeDeleted = new Request("PUT", "/" + indexName + "/_doc/to_be_deleted");
+            toBeDeleted.addParameter("refresh", "true");
+            toBeDeleted.setJsonEntity("{\"f1\": \"delete-me\"}");
+            client().performRequest(toBeDeleted);
+            waitForSearchableDocs(indexName, shardCount, replicaCount);
+            assertCount(indexName, expectedCount + 6);
+
+            logger.info("--> Delete previously added doc and verify doc count");
+            Request delete = new Request("DELETE", "/" + indexName + "/_doc/to_be_deleted");
+            delete.addParameter("refresh", "true");
+            client().performRequest(delete);
+            waitForSearchableDocs(indexName, shardCount, replicaCount);
+            assertCount(indexName, expectedCount + 5);
+        }
+    }
+
     public void testAutoIdWithOpTypeCreate() throws IOException {
         final String indexName = "auto_id_and_op_type_create_index";
         StringBuilder b = new StringBuilder();
@@ -214,12 +415,14 @@ private void bulk(String index, String valueSuffix, int count) throws IOExceptio
         client().performRequest(bulk);
     }
 
-    private void assertCount(String index, int count) throws IOException {
-        Request searchTestIndexRequest = new Request("POST", "/" + index + "/_search");
-        searchTestIndexRequest.addParameter(TOTAL_HITS_AS_INT_PARAM, "true");
-        searchTestIndexRequest.addParameter("filter_path", "hits.total");
-        Response searchTestIndexResponse = client().performRequest(searchTestIndexRequest);
-        assertEquals("{\"hits\":{\"total\":" + count + "}}",
+    private void assertCount(String index, int count) throws Exception {
+        assertBusy(() -> {
+            Request searchTestIndexRequest = new Request("POST", "/" + index + "/_search");
+            searchTestIndexRequest.addParameter(TOTAL_HITS_AS_INT_PARAM, "true");
+            searchTestIndexRequest.addParameter("filter_path", "hits.total");
+            Response searchTestIndexResponse = client().performRequest(searchTestIndexRequest);
+            assertEquals("{\"hits\":{\"total\":" + count + "}}",
                 EntityUtils.toString(searchTestIndexResponse.getEntity(), StandardCharsets.UTF_8));
+        }, 30, TimeUnit.SECONDS);
     }
 }
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/JodaCompatibilityIT.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/JodaCompatibilityIT.java
index 0ef1e3a5050af..32d545481c523 100644
--- a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/JodaCompatibilityIT.java
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/JodaCompatibilityIT.java
@@ -40,7 +40,7 @@
 import org.opensearch.client.Response;
 import org.opensearch.client.WarningsHandler;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.junit.BeforeClass;
 
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/MappingTypeRemovalIT.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/MappingTypeRemovalIT.java
new file mode 100644
index 0000000000000..e36abcff11661
--- /dev/null
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/MappingTypeRemovalIT.java
@@ -0,0 +1,310 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.upgrades;
+
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.client.methods.HttpPut;
+import org.apache.http.util.EntityUtils;
+import org.opensearch.Version;
+import org.opensearch.client.Request;
+import org.opensearch.client.RequestOptions;
+import org.opensearch.client.Response;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.regex.Pattern;
+
+import static org.opensearch.rest.action.search.RestSearchAction.TOTAL_HITS_AS_INT_PARAM;
+
+/**
+ * Tests to ensure indices, snapshots, templates created using type mapping before {@link Version#V_2_0_0}
+ * survive the rolling upgrade to {@link Version#V_2_0_0}. The tests include indexing, re-indexing,
+ * snapshot and restore, template based index creation for type mapped indices to ensure they are accessible
+ * and searchable in {@link Version#V_2_0_0}.
+ */
+public class MappingTypeRemovalIT extends AbstractRollingTestCase {
+
+    public void testTypeRemovalIndexing() throws IOException {
+        final String indexName = "test_index_with_mapping";
+        final String indexWithoutTypeName = "test_index_without_mapping";
+        final String templateIndexName = "template_test_index";
+        final String templateName = "test_template";
+        final String indexNamePattern = "template_test*";
+
+        final String mapping = "\"properties\":{\"f1\":{\"type\":\"keyword\"},\"f2\":{\"type\":\"keyword\"}}";
+        final String typeMapping = "\"_doc\":{" + mapping +"}";
+
+        switch (CLUSTER_TYPE) {
+            case OLD:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    Settings.Builder settings = Settings.builder()
+                        .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+                        .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0);
+                    createIndexWithDocMappings(indexName, settings.build(), typeMapping);
+                    assertIndexMapping(indexName, mapping);
+
+                    createTemplate(templateName, indexNamePattern, typeMapping);
+                    createIndex(templateIndexName, settings.build());
+                    assertIndexMapping(templateIndexName, mapping);
+                    bulk(indexName, CLUSTER_TYPE.name(), 1);
+                    bulk(templateIndexName, CLUSTER_TYPE.name(), 1);
+
+                    createIndex(indexWithoutTypeName, settings.build());
+                    bulk(indexWithoutTypeName, CLUSTER_TYPE.name(), 1);
+                }
+                break;
+            case MIXED:
+                waitForClusterGreenStatus();
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    assertCount(indexName, 1, 1);
+                    assertCount(templateIndexName, 1, 1);
+                    assertCount(indexWithoutTypeName, 1, 1);
+                }
+                break;
+            case UPGRADED:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    // Assert documents created with mapping prior to OS 2.0 are accessible.
+                    assertCount(indexName, 1, 1);
+                    bulk(indexName, CLUSTER_TYPE.name(), 1);
+                    // Assert the newly ingested documents are accessible
+                    assertCount(indexName, 2, 1);
+
+                    // Assert documents created with mapping on index with template prior to OS 2.0 are accessible.
+                    assertCount(templateIndexName, 1, 1);
+                    bulk(templateIndexName, CLUSTER_TYPE.name(), 1);
+                    // Assert the newly ingested documents with template are accessible
+                    assertCount(templateIndexName, 2, 1);
+
+                    // Assert documents created prior to OS 2.0 are accessible.
+                    assertCount(indexWithoutTypeName, 1, 1);
+                    // Test ingestion of new documents created using < OS2.0
+                    bulk(indexWithoutTypeName, CLUSTER_TYPE.name(), 1);
+                    assertCount(indexWithoutTypeName, 2, 1);
+                }
+                break;
+            default:
+                throw new UnsupportedOperationException("Unknown cluster type [" + CLUSTER_TYPE + "]");
+        }
+    }
+
+    public void testTypeRemovalReindexing() throws IOException {
+        final String indexName = "test_reindex_with_mapping";
+        final String reindexName = "test_reindex_with_mapping_v2";
+
+        final String originalMapping = "\"properties\":{\"f1\":{\"type\":\"keyword\"},\"f2\":{\"type\":\"keyword\"}}";
+        final String originalTypeMapping = "\"_doc\":{" + originalMapping +"}";
+
+        final String newMapping = "\"properties\":{\"f1\":{\"type\":\"text\"},\"f2\":{\"type\":\"text\"}}";
+        final String newTypeMapping = "\"_doc\":{" + newMapping +"}";
+
+        switch (CLUSTER_TYPE) {
+            case OLD:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    Settings.Builder settings = Settings.builder()
+                        .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+                        .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0);
+                    createIndexWithDocMappings(indexName, settings.build(), originalTypeMapping);
+                    assertIndexMapping(indexName, originalMapping);
+
+                    createIndexWithDocMappings(reindexName, settings.build(), newTypeMapping);
+                    assertIndexMapping(reindexName, newMapping);
+                    bulk(indexName, CLUSTER_TYPE.name(), 1);
+                }
+                break;
+            case MIXED:
+                waitForClusterGreenStatus();
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    assertCount(indexName, 1, 1);
+                }
+                break;
+            case UPGRADED:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    // Assert documents created with mapping prior to OS 2.0 are accessible.
+                    assertCount(indexName, 1, 1);
+                    bulk(indexName, CLUSTER_TYPE.name(), 1);
+                    // Assert the newly ingested documents are accessible
+                    assertCount(indexName, 2, 1);
+
+                    reindex(indexName, reindexName);
+                    assertCount(reindexName, 2, 1);
+                    assertIndexMapping(reindexName, newMapping);
+                }
+                break;
+            default:
+                throw new UnsupportedOperationException("Unknown cluster type [" + CLUSTER_TYPE + "]");
+        }
+    }
+
+    public void testTypeRemovalSnapshots() throws IOException {
+        final String indexName = "test_snapshot_index";
+        final String repositoryName = "test_repository";
+        final String snapshotName = "force_preserve_test_snapshot";
+
+        final String mapping = "\"properties\":{\"f1\":{\"type\":\"keyword\"},\"f2\":{\"type\":\"keyword\"}}";
+        final String typeMapping = "\"_doc\":{" + mapping +"}";
+
+        switch (CLUSTER_TYPE) {
+            case OLD:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    Settings.Builder settings = Settings.builder()
+                        .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+                        .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0);
+                    createIndexWithDocMappings(indexName, settings.build(), typeMapping);
+                    assertIndexMapping(indexName, mapping);
+                    bulk(indexName, CLUSTER_TYPE.name(), 1);
+
+                    registerRepository(repositoryName,"fs", true, Settings.builder()
+                        .put("location", REPOSITORY_LOCATION)
+                        .build());
+                    createSnapshotIfNotExists(repositoryName, snapshotName, true, indexName);
+                    deleteIndex(indexName);
+                }
+                break;
+            case MIXED:
+                waitForClusterGreenStatus();
+                break;
+            case UPGRADED:
+                if (UPGRADE_FROM_VERSION.before(Version.V_2_0_0)) {
+                    registerRepository(repositoryName,"fs", true, Settings.builder()
+                        .put("location", REPOSITORY_LOCATION)
+                        .build());
+                    assertFalse(indexExists(indexName));;
+                    restoreSnapshot(repositoryName, snapshotName, true);
+                    assertCount(indexName, 1, 1);
+                }
+                break;
+            default:
+                throw new UnsupportedOperationException("Unknown cluster type [" + CLUSTER_TYPE + "]");
+        }
+    }
+
+    private void bulk(String index, String valueSuffix, int count) throws IOException {
+        StringBuilder b = new StringBuilder();
+        for (int i = 0; i < count; i++) {
+            b.append("{\"index\": {\"_index\": \"").append(index).append("\"}}\n");
+            b.append("{\"f1\": \"v").append(i).append(valueSuffix).append("\", \"f2\": ").append(i).append("}\n");
+        }
+        Request bulk = new Request(HttpPost.METHOD_NAME, "/_bulk");
+        bulk.addParameter("refresh", "true");
+        bulk.setJsonEntity(b.toString());
+        client().performRequest(bulk);
+    }
+
+    private void createIndexWithDocMappings(String index, Settings settings, String mapping) throws IOException {
+        Request createIndexWithMappingsRequest = new Request(HttpPut.METHOD_NAME, "/" + index);
+        String entity = "{\"settings\": " + Strings.toString(MediaTypeRegistry.JSON, settings);
+        if (mapping != null) {
+            entity += ",\"mappings\" : {" + mapping + "}";
+        }
+        entity += "}";
+        createIndexWithMappingsRequest.addParameter("include_type_name", "true");
+        createIndexWithMappingsRequest.setJsonEntity(entity);
+        useIgnoreTypesRemovalWarningsHandler(createIndexWithMappingsRequest);
+        client().performRequest(createIndexWithMappingsRequest);
+    }
+
+    private void createTemplate(String templateName, String indexPattern, String mapping) throws IOException {
+        Request templateRequest = new Request(HttpPut.METHOD_NAME, "/_template/" + templateName);
+        String entity = "{\"index_patterns\": \"" + indexPattern + "\"";
+        if (mapping != null) {
+            entity += ",\"mappings\" : {" + mapping + "}";
+        }
+        entity += "}";
+        templateRequest.addParameter("include_type_name", "true");
+        templateRequest.setJsonEntity(entity);
+        useIgnoreTypesRemovalWarningsHandler(templateRequest);
+        client().performRequest(templateRequest);
+    }
+
+    private void reindex(String originalIndex, String newIndex) throws IOException {
+        Request reIndexRequest = new Request(HttpPost.METHOD_NAME, "/_reindex/");
+        String entity = "{ \"source\": { \"index\": \"" + originalIndex + "\" }, \"dest\": { \"index\": \"" + newIndex + "\" } }";
+        reIndexRequest.setJsonEntity(entity);
+        reIndexRequest.addParameter("refresh", "true");
+        client().performRequest(reIndexRequest);
+    }
+
+    private void assertIndexMapping(String index, String mappings) throws IOException {
+        Request testIndexMappingRequest = new Request(HttpGet.METHOD_NAME, "/" + index + "/_mapping");
+        Response testIndexMappingResponse = client().performRequest(testIndexMappingRequest);
+        assertEquals("{\""+index+"\":{\"mappings\":{"+mappings+"}}}",
+            EntityUtils.toString(testIndexMappingResponse.getEntity(), StandardCharsets.UTF_8));
+    }
+
+    private void assertCount(String index, int count, Integer totalShards) throws IOException {
+        Request searchTestIndexRequest = new Request(HttpPost.METHOD_NAME, "/" + index + "/_search");
+        searchTestIndexRequest.addParameter(TOTAL_HITS_AS_INT_PARAM, "true");
+        if (totalShards != null) {
+            searchTestIndexRequest.addParameter("filter_path", "hits.total,_shards");
+        } else {
+            searchTestIndexRequest.addParameter("filter_path", "hits.total");
+        }
+
+        Response searchTestIndexResponse = client().performRequest(searchTestIndexRequest);
+        String expectedResponse;
+        if (totalShards != null) {
+            expectedResponse = "{\"_shards\":{\"total\":" + totalShards + ",\"successful\":" + totalShards + ",\"skipped\":0,\"failed\":0},\"hits\":{\"total\":" + count + "}}";
+        } else {
+            expectedResponse = "{\"hits\":{\"total\":" + count + "}}";
+        }
+        assertEquals(expectedResponse,
+            EntityUtils.toString(searchTestIndexResponse.getEntity(), StandardCharsets.UTF_8));
+    }
+
+    private final Pattern TYPE_REMOVAL_WARNING = Pattern.compile(
+        "^\\[types removal\\] (.+) include_type_name (.+) is deprecated\\. The parameter will be removed in the next major version\\.$"
+    );
+
+    private void useIgnoreTypesRemovalWarningsHandler(Request request) {
+        RequestOptions.Builder options = request.getOptions().toBuilder();
+        options.setWarningsHandler(warnings -> {
+            if (warnings.size() > 0) {
+                boolean matches = warnings.stream()
+                    .anyMatch(
+                        message -> TYPE_REMOVAL_WARNING.matcher(message).matches()
+                    );
+                return matches == false;
+            } else {
+                return false;
+            }
+        });
+        request.setOptions(options);
+    }
+
+    private void createSnapshotIfNotExists(String repository, String snapshot, boolean waitForCompletion, String indexName) throws IOException {
+        final Request getSnapshotsRequest = new Request(HttpGet.METHOD_NAME, "_cat/snapshots/" + repository);
+        final Response getSnapshotsResponse = client().performRequest(getSnapshotsRequest);
+        if (!EntityUtils.toString(getSnapshotsResponse.getEntity(), StandardCharsets.UTF_8).contains(snapshot)) {
+            final Request request = new Request(HttpPut.METHOD_NAME, "_snapshot/" + repository + '/' + snapshot);
+            request.addParameter("wait_for_completion", Boolean.toString(waitForCompletion));
+            if (indexName != null) {
+                String entity = "{\"indices\" : \"" + indexName + "\"}";
+                request.setJsonEntity(entity);
+            }
+
+            final Response response = client().performRequest(request);
+            assertEquals(
+                "Failed to create snapshot [" + snapshot + "] in repository [" + repository + "]: " + response,
+                response.getStatusLine().getStatusCode(), RestStatus.OK.getStatus()
+            );
+        }
+    }
+
+    private void waitForClusterGreenStatus() throws IOException {
+        Request waitForGreen = new Request(HttpGet.METHOD_NAME, "/_cluster/health");
+        waitForGreen.addParameter("wait_for_nodes", "3");
+        client().performRequest(waitForGreen);
+    }
+}
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/RecoveryIT.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/RecoveryIT.java
index 687fd1743c3d3..71ea1b95a1786 100644
--- a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/RecoveryIT.java
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/RecoveryIT.java
@@ -42,12 +42,13 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.rest.yaml.ObjectPath;
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
@@ -90,7 +91,7 @@ public void testHistoryUUIDIsGenerated() throws Exception {
                 .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                 .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                 // if the node with the replica is the first to be restarted, while a replica is still recovering
-                // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                 // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                 // before timing out
                 .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms");
@@ -158,7 +159,7 @@ public void testRecoveryWithConcurrentIndexing() throws Exception {
                     .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                     .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 2)
                     // if the node with the replica is the first to be restarted, while a replica is still recovering
-                    // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                    // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                     // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                     // before timing out
                     .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
@@ -256,7 +257,7 @@ public void testRelocationWithConcurrentIndexing() throws Exception {
                     .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                     .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 2)
                     // if the node with the replica is the first to be restarted, while a replica is still recovering
-                    // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                    // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                     // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                     // before timing out
                     .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
@@ -266,7 +267,7 @@ public void testRelocationWithConcurrentIndexing() throws Exception {
                 indexDocs(index, 0, 10);
                 ensureGreen(index);
                 // make sure that no shards are allocated, so we can make sure the primary stays on the old node (when one
-                // node stops, we lose the master too, so a replica will not be promoted)
+                // node stops, we lose the cluster-manager too, so a replica will not be promoted)
                 updateIndexSettings(index, Settings.builder().put(INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.getKey(), "none"));
                 break;
             case MIXED:
@@ -330,7 +331,7 @@ public void testRecovery() throws Exception {
                 .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                 .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                 // if the node with the replica is the first to be restarted, while a replica is still recovering
-                // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                 // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                 // before timing out
                 .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
@@ -448,7 +449,7 @@ public void testRecoveryClosedIndex() throws Exception {
                 .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                 .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                 // if the node with the replica is the first to be restarted, while a replica is still recovering
-                // then delayed allocation will kick in. When the node comes back, the master will search for a copy
+                // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                 // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                 // before timing out
                 .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
@@ -800,7 +801,7 @@ public void testSoftDeletesDisabledWarning() throws Exception {
                 settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), softDeletesEnabled);
             }
             Request request = new Request("PUT", "/" + indexName);
-            request.setJsonEntity("{\"settings\": " + Strings.toString(settings.build()) + "}");
+            request.setJsonEntity("{\"settings\": " + Strings.toString(MediaTypeRegistry.JSON, settings.build()) + "}");
             if (softDeletesEnabled == false) {
                 expectSoftDeletesWarning(request, indexName);
             }
diff --git a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/SystemIndicesUpgradeIT.java b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/SystemIndicesUpgradeIT.java
index c50af0084b000..22b6b4a201877 100644
--- a/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/SystemIndicesUpgradeIT.java
+++ b/qa/rolling-upgrade/src/test/java/org/opensearch/upgrades/SystemIndicesUpgradeIT.java
@@ -34,13 +34,17 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
+import org.hamcrest.MatcherAssert;
 import org.opensearch.client.Request;
+import org.opensearch.client.Response;
 import org.opensearch.client.ResponseException;
 import org.opensearch.test.XContentTestUtils.JsonMapView;
 
+import java.io.IOException;
 import java.util.Map;
 
 import static org.opensearch.cluster.metadata.IndexNameExpressionResolver.SYSTEM_INDEX_ENFORCEMENT_VERSION;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
@@ -68,25 +72,7 @@ public void testSystemIndicesUpgrades() throws Exception {
             }
             client().performRequest(bulk);
 
-            // start a async reindex job
-            Request reindex = new Request("POST", "/_reindex");
-            reindex.setJsonEntity(
-                "{\n" +
-                    "  \"source\":{\n" +
-                    "    \"index\":\"test_index_old\"\n" +
-                    "  },\n" +
-                    "  \"dest\":{\n" +
-                    "    \"index\":\"test_index_reindex\"\n" +
-                    "  }\n" +
-                    "}");
-            reindex.addParameter("wait_for_completion", "false");
-            Map<String, Object> response = entityAsMap(client().performRequest(reindex));
-            String taskId = (String) response.get("task");
-
-            // wait for task
-            Request getTask = new Request("GET", "/_tasks/" + taskId);
-            getTask.addParameter("wait_for_completion", "true");
-            client().performRequest(getTask);
+            createAndVerifyStoredTask();
 
             // make sure .tasks index exists
             Request getTasksIndex = new Request("GET", "/.tasks");
@@ -121,6 +107,8 @@ public void testSystemIndicesUpgrades() throws Exception {
                 assertThat(client().performRequest(putAliasRequest).getStatusLine().getStatusCode(), is(200));
             }
         } else if (CLUSTER_TYPE == ClusterType.UPGRADED) {
+            createAndVerifyStoredTask();
+
             assertBusy(() -> {
                 Request clusterStateRequest = new Request("GET", "/_cluster/state/metadata");
                 Map<String, Object> indices = new JsonMapView(entityAsMap(client().performRequest(clusterStateRequest)))
@@ -152,4 +140,29 @@ public void testSystemIndicesUpgrades() throws Exception {
             });
         }
     }
+
+    /**
+     * Completed tasks get persisted into the .tasks index, so this method waits
+     * until the task is completed in order to verify that it has been successfully
+     * written to the index and can be retrieved.
+     */
+    private static void createAndVerifyStoredTask() throws Exception {
+        // Use update by query to create an async task
+        final Request updateByQueryRequest = new Request("POST", "/test_index_old/_update_by_query");
+        updateByQueryRequest.addParameter("wait_for_completion", "false");
+        final Response updateByQueryResponse = client().performRequest(updateByQueryRequest);
+        MatcherAssert.assertThat(updateByQueryResponse.getStatusLine().getStatusCode(), equalTo(200));
+        final String taskId = (String) entityAsMap(updateByQueryResponse).get("task");
+
+        // wait for task to complete
+        waitUntil(() -> {
+            try {
+                final Response getTaskResponse = client().performRequest(new Request("GET", "/_tasks/" + taskId));
+                MatcherAssert.assertThat(getTaskResponse.getStatusLine().getStatusCode(), equalTo(200));
+                return (Boolean) entityAsMap(getTaskResponse).get("completed");
+            } catch (IOException e) {
+                throw new AssertionError(e);
+            }
+        });
+    }
 }
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/10_basic.yml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/10_basic.yml
index e1ffcea930a42..840c7f5f6297e 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/10_basic.yml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/10_basic.yml
@@ -204,4 +204,3 @@
       tasks.get:
         wait_for_completion: true
         task_id: $task
-
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/20_date_range.yml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/20_date_range.yml
index 89992eeba616f..6427a45e19f58 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/20_date_range.yml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/20_date_range.yml
@@ -111,5 +111,3 @@
                 gte: "2019-02-01T00:00+01:00"
                 lte: "2019-02-01T00:00+01:00"
   - match: { hits.total: 1 }
-
-
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yml
index cb74c33cbd31a..f1c00ee896f92 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yml
@@ -133,5 +133,3 @@
         wait_for_completion: true
         task_id: $task_id
   - match: { task.headers.X-Opaque-Id: "Reindexing Again" }
-
-
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/20_date_range.yml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/20_date_range.yml
index 7dae2a4d6241a..026dcff32e175 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/20_date_range.yml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/20_date_range.yml
@@ -38,4 +38,3 @@
               time_frame:
                 gte: "2019-02-01T00:00+01:00"
                 lte: "2019-02-01T00:00+01:00"
-
diff --git a/qa/smoke-test-http/build.gradle b/qa/smoke-test-http/build.gradle
index 2402c9b807283..f48ddc26d929b 100644
--- a/qa/smoke-test-http/build.gradle
+++ b/qa/smoke-test-http/build.gradle
@@ -35,7 +35,8 @@ apply plugin: 'opensearch.test-with-dependencies'
 
 dependencies {
   testImplementation project(path: ':modules:transport-netty4') // for http
-  testImplementation project(path: ':plugins:transport-nio') // for http
+  testImplementation project(path: ':plugins:transport-nio')
+  testImplementation project(path: ':plugins:identity-shiro') // for http
 }
 
 integTest {
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/AwarenessAttributeDecommissionRestIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/AwarenessAttributeDecommissionRestIT.java
new file mode 100644
index 0000000000000..61afb3ffdcf98
--- /dev/null
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/AwarenessAttributeDecommissionRestIT.java
@@ -0,0 +1,102 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.http;
+
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
+import org.opensearch.client.Request;
+import org.opensearch.client.Response;
+import org.opensearch.client.ResponseException;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.test.NodeRoles.onlyRole;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class AwarenessAttributeDecommissionRestIT extends HttpSmokeTestCase{
+
+    public void testRestStatusForDecommissioningFailedException() {
+        internalCluster().startNodes(3);
+        Request request = new Request("PUT", "/_cluster/decommission/awareness/zone/zone-1");
+        ResponseException exception = expectThrows(
+            ResponseException.class,
+            () -> getRestClient().performRequest(request)
+        );
+        assertEquals(exception.getResponse().getStatusLine().getStatusCode(), RestStatus.BAD_REQUEST.getStatus());
+        assertTrue(exception.getMessage().contains("invalid awareness attribute requested for decommissioning"));
+    }
+
+    public void testRestStatusForAcknowledgedDecommission() throws IOException {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        ensureStableCluster(6);
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        Request request = new Request("PUT", "/_cluster/decommission/awareness/zone/c");
+        Response response = getRestClient().performRequest(request);
+        assertEquals(response.getStatusLine().getStatusCode(), RestStatus.OK.getStatus());
+    }
+}
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/DanglingIndicesRestIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/DanglingIndicesRestIT.java
index d5dcde2492046..42c7fd667fd8f 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/DanglingIndicesRestIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/DanglingIndicesRestIT.java
@@ -54,8 +54,8 @@
 import static org.opensearch.cluster.metadata.IndexGraveyard.SETTING_MAX_TOMBSTONES;
 import static org.opensearch.gateway.DanglingIndicesState.AUTO_IMPORT_DANGLING_INDICES_SETTING;
 import static org.opensearch.indices.IndicesService.WRITE_DANGLING_INDICES_INFO_SETTING;
-import static org.opensearch.rest.RestStatus.ACCEPTED;
-import static org.opensearch.rest.RestStatus.OK;
+import static org.opensearch.core.rest.RestStatus.ACCEPTED;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.test.XContentTestUtils.createJsonMapView;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
@@ -91,7 +91,7 @@ private Settings buildSettings(int maxTombstones) {
      * Check that when dangling indices are discovered, then they can be listed via the REST API.
      */
     public void testDanglingIndicesCanBeListed() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(1);
+        internalCluster().setBootstrapClusterManagerNodeIndex(1);
         internalCluster().startNodes(3, buildSettings(0));
 
         final DanglingIndexDetails danglingIndexDetails = createDanglingIndices(INDEX_NAME);
@@ -121,7 +121,7 @@ public void testDanglingIndicesCanBeListed() throws Exception {
      * Check that dangling indices can be imported.
      */
     public void testDanglingIndicesCanBeImported() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(1);
+        internalCluster().setBootstrapClusterManagerNodeIndex(1);
         internalCluster().startNodes(3, buildSettings(0));
 
         createDanglingIndices(INDEX_NAME);
@@ -135,7 +135,7 @@ public void testDanglingIndicesCanBeImported() throws Exception {
         importRequest.addParameter("accept_data_loss", "true");
         // Ensure this parameter is accepted
         importRequest.addParameter("timeout", "20s");
-        importRequest.addParameter("master_timeout", "20s");
+        importRequest.addParameter("cluster_manager_timeout", "20s");
         final Response importResponse = restClient.performRequest(importRequest);
         assertThat(importResponse.getStatusLine().getStatusCode(), equalTo(ACCEPTED.getStatus()));
 
@@ -157,7 +157,7 @@ public void testDanglingIndicesCanBeImported() throws Exception {
      * deleted through the API
      */
     public void testDanglingIndicesCanBeDeleted() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(1);
+        internalCluster().setBootstrapClusterManagerNodeIndex(1);
         internalCluster().startNodes(3, buildSettings(1));
 
         createDanglingIndices(INDEX_NAME, OTHER_INDEX_NAME);
@@ -171,7 +171,7 @@ public void testDanglingIndicesCanBeDeleted() throws Exception {
         deleteRequest.addParameter("accept_data_loss", "true");
         // Ensure these parameters is accepted
         deleteRequest.addParameter("timeout", "20s");
-        deleteRequest.addParameter("master_timeout", "20s");
+        deleteRequest.addParameter("cluster_manager_timeout", "20s");
         final Response deleteResponse = restClient.performRequest(deleteRequest);
         assertThat(deleteResponse.getStatusLine().getStatusCode(), equalTo(ACCEPTED.getStatus()));
 
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/DetailedErrorsEnabledIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/DetailedErrorsEnabledIT.java
index 090a572ef0d6a..d91a96e0174fc 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/DetailedErrorsEnabledIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/DetailedErrorsEnabledIT.java
@@ -57,7 +57,7 @@ public void testThatErrorTraceWorksByDefault() throws IOException {
             Response response = e.getResponse();
             assertThat(response.getHeader("Content-Type"), containsString("application/json"));
             assertThat(EntityUtils.toString(response.getEntity()),
-                    containsString("\"stack_trace\":\"[Validation Failed: 1: index / indices is missing;]; " +
+                    containsString("\"stack_trace\":\"OpenSearchException[Validation Failed: 1: index / indices is missing;]; " +
                     "nested: ActionRequestValidationException[Validation Failed: 1:"));
         }
 
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/IdentityAuthenticationIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/IdentityAuthenticationIT.java
new file mode 100644
index 0000000000000..2772f902e7ea1
--- /dev/null
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/IdentityAuthenticationIT.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.http;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Collection;
+import org.junit.Assert;
+import org.opensearch.client.Request;
+import org.opensearch.client.RequestOptions;
+import org.opensearch.client.Response;
+import org.opensearch.client.ResponseException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.identity.shiro.ShiroIdentityPlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.core.rest.RestStatus;
+
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.Netty4Plugin;
+import org.opensearch.transport.nio.NioTransportPlugin;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.core.StringContains.containsString;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, supportsDedicatedMasters = false, numDataNodes = 1)
+public class IdentityAuthenticationIT extends HttpSmokeTestCase {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(FeatureFlags.IDENTITY, "true")
+            .build();
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(OpenSearchTestCase.getTestTransportPlugin(), Netty4Plugin.class, NioTransportPlugin.class, ShiroIdentityPlugin.class);
+    }
+
+
+    public void testBasicAuthSuccess() throws Exception {
+        final Response response = createHealthRequest("Basic YWRtaW46YWRtaW4="); // admin:admin
+        final String content = new String(response.getEntity().getContent().readAllBytes(), StandardCharsets.UTF_8);
+
+        Assert.assertThat(content, response.getStatusLine().getStatusCode(), equalTo(RestStatus.OK.getStatus()));
+        Assert.assertThat(content, containsString("green"));
+    }
+
+    public void testBasicAuthUnauthorized_invalidHeader() throws Exception {
+        final Response response = createHealthRequest("Basic aaaa"); // invalid username password
+        final String content = new String(response.getEntity().getContent().readAllBytes(), StandardCharsets.UTF_8);
+
+        Assert.assertThat(content, response.getStatusLine().getStatusCode(), equalTo(RestStatus.UNAUTHORIZED.getStatus()));
+        Assert.assertThat(content, containsString("Illegally formed basic authorization header"));
+    }
+
+    public void testBasicAuthUnauthorized_wrongPassword() throws Exception {
+        final Response response = createHealthRequest("Basic YWRtaW46aW52YWxpZFBhc3N3b3Jk"); // admin:invalidPassword
+        final String content = new String(response.getEntity().getContent().readAllBytes(), StandardCharsets.UTF_8);
+
+        Assert.assertThat(content, response.getStatusLine().getStatusCode(), equalTo(RestStatus.UNAUTHORIZED.getStatus()));
+    }
+
+    public void testBasicAuthUnauthorized_unknownUser() throws Exception {
+        final Response response = createHealthRequest("Basic dXNlcjpkb2VzTm90RXhpc3Q="); // user:doesNotExist
+        final String content = new String(response.getEntity().getContent().readAllBytes(), StandardCharsets.UTF_8);
+
+        Assert.assertThat(content, response.getStatusLine().getStatusCode(), equalTo(RestStatus.UNAUTHORIZED.getStatus()));
+    }
+
+    private Response createHealthRequest(final String authorizationHeaderValue) throws Exception {
+        final Request request = new Request("GET", "/_cluster/health");
+        final RequestOptions options = RequestOptions.DEFAULT.toBuilder().addHeader("Authorization", authorizationHeaderValue).build();
+        request.setOptions(options);
+
+        try {
+            final Response response = OpenSearchIntegTestCase.getRestClient().performRequest(request);
+            return response;
+        } catch (final ResponseException re) {
+            return re.getResponse();
+        }
+    }
+}
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/IndexingPressureRestIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/IndexingPressureRestIT.java
index bac4304db1ef6..6ff2dee2812e9 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/IndexingPressureRestIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/IndexingPressureRestIT.java
@@ -46,9 +46,9 @@
 import java.util.ArrayList;
 import java.util.Map;
 
-import static org.opensearch.rest.RestStatus.CREATED;
-import static org.opensearch.rest.RestStatus.OK;
-import static org.opensearch.rest.RestStatus.TOO_MANY_REQUESTS;
+import static org.opensearch.core.rest.RestStatus.CREATED;
+import static org.opensearch.core.rest.RestStatus.OK;
+import static org.opensearch.core.rest.RestStatus.TOO_MANY_REQUESTS;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.lessThan;
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
index a13d406f7b133..2126652865330 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
@@ -34,7 +34,6 @@
 import org.apache.http.entity.ContentType;
 import org.apache.http.nio.entity.NByteArrayEntity;
 import org.apache.logging.log4j.LogManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
@@ -48,8 +47,10 @@
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
 import org.opensearch.client.ResponseListener;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.script.MockScriptPlugin;
@@ -59,7 +60,7 @@
 import org.opensearch.search.lookup.LeafFieldsLookup;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.transport.TransportService;
@@ -98,12 +99,12 @@ public void testAutomaticCancellationDuringQueryPhase() throws Exception {
         Request searchRequest = new Request("GET", "/test/_search");
         SearchSourceBuilder searchSource = new SearchSourceBuilder().query(scriptQuery(
             new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())));
-        searchRequest.setJsonEntity(Strings.toString(searchSource));
+        searchRequest.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, searchSource));
         verifyCancellationDuringQueryPhase(SearchAction.NAME, searchRequest);
     }
 
     public void testAutomaticCancellationMultiSearchDuringQueryPhase() throws Exception {
-        XContentType contentType = XContentType.JSON;
+        MediaType contentType = MediaTypeRegistry.JSON;
         MultiSearchRequest multiSearchRequest = new MultiSearchRequest().add(new SearchRequest("test")
             .source(new SearchSourceBuilder().scriptField("test_field",
                 new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap()))));
@@ -147,12 +148,12 @@ public void testAutomaticCancellationDuringFetchPhase() throws Exception {
         Request searchRequest = new Request("GET", "/test/_search");
         SearchSourceBuilder searchSource = new SearchSourceBuilder().scriptField("test_field",
             new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap()));
-        searchRequest.setJsonEntity(Strings.toString(searchSource));
+        searchRequest.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, searchSource));
         verifyCancellationDuringFetchPhase(SearchAction.NAME, searchRequest);
     }
 
     public void testAutomaticCancellationMultiSearchDuringFetchPhase() throws Exception {
-        XContentType contentType = XContentType.JSON;
+        MediaType contentType = MediaTypeRegistry.JSON;
         MultiSearchRequest multiSearchRequest = new MultiSearchRequest().add(new SearchRequest("test")
             .source(new SearchSourceBuilder().scriptField("test_field",
                 new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap()))));
@@ -183,6 +184,7 @@ public void onFailure(Exception exception) {
             }
         });
 
+        latch.await(2, TimeUnit.SECONDS);
         awaitForBlock(plugins);
         cancellable.cancel();
         ensureSearchTaskIsCancelled(searchAction, nodeIdToName::get);
@@ -297,7 +299,7 @@ public Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
         }
     }
 
-    private static ContentType createContentType(final XContentType xContentType) {
-        return ContentType.create(xContentType.mediaTypeWithoutParameters(), (Charset) null);
+    private static ContentType createContentType(final MediaType mediaType) {
+        return ContentType.create(mediaType.mediaTypeWithoutParameters(), (Charset) null);
     }
 }
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/ShardIndexingPressureRestIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/ShardIndexingPressureRestIT.java
index c018bc68e051a..9e663ac042d91 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/ShardIndexingPressureRestIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/ShardIndexingPressureRestIT.java
@@ -19,9 +19,9 @@
 import java.util.ArrayList;
 import java.util.Map;
 
-import static org.opensearch.rest.RestStatus.CREATED;
-import static org.opensearch.rest.RestStatus.OK;
-import static org.opensearch.rest.RestStatus.TOO_MANY_REQUESTS;
+import static org.opensearch.core.rest.RestStatus.CREATED;
+import static org.opensearch.core.rest.RestStatus.OK;
+import static org.opensearch.core.rest.RestStatus.TOO_MANY_REQUESTS;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.lessThan;
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/SystemIndexRestIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/SystemIndexRestIT.java
index e687e5eb8a151..9f2d686251947 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/SystemIndexRestIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/SystemIndexRestIT.java
@@ -157,7 +157,7 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
                                                  IndexScopedSettings indexScopedSettings, SettingsFilter settingsFilter,
                                                  IndexNameExpressionResolver indexNameExpressionResolver,
                                                  Supplier<DiscoveryNodes> nodesInCluster) {
-            return org.opensearch.common.collect.List.of(new AddDocRestHandler());
+            return List.of(new AddDocRestHandler());
         }
 
         @Override
@@ -178,7 +178,7 @@ public String getName() {
 
             @Override
             public List<Route> routes() {
-                return org.opensearch.common.collect.List.of(new Route(RestRequest.Method.POST, "/_sys_index_test/add_doc/{id}"));
+                return List.of(new Route(RestRequest.Method.POST, "/_sys_index_test/add_doc/{id}"));
             }
 
             @Override
@@ -186,7 +186,7 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
                 IndexRequest indexRequest = new IndexRequest(SYSTEM_INDEX_NAME);
                 indexRequest.id(request.param("id"));
                 indexRequest.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
-                indexRequest.source(org.opensearch.common.collect.Map.of("some_field", "some_value"));
+                indexRequest.source(Map.of("some_field", "some_value"));
                 return channel -> client.index(indexRequest,
                     new RestStatusToXContentListener<>(channel, r -> r.getLocation(indexRequest.routing())));
             }
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/TestResponseHeaderRestAction.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/TestResponseHeaderRestAction.java
index c95b4f0070a80..6cf92626e335a 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/TestResponseHeaderRestAction.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/TestResponseHeaderRestAction.java
@@ -36,7 +36,7 @@
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.util.List;
 
diff --git a/qa/smoke-test-ingest-disabled/build.gradle b/qa/smoke-test-ingest-disabled/build.gradle
index d7676a5b5ecbd..79abbf84fbc09 100644
--- a/qa/smoke-test-ingest-disabled/build.gradle
+++ b/qa/smoke-test-ingest-disabled/build.gradle
@@ -38,5 +38,5 @@ dependencies {
 }
 
 testClusters.integTest {
-  setting 'node.roles', '[data,master,remote_cluster_client]'
+  setting 'node.roles', '[data,cluster_manager,remote_cluster_client]'
 }
diff --git a/qa/smoke-test-ingest-disabled/src/test/resources/rest-api-spec/test/ingest_mustache/10_ingest_disabled.yml b/qa/smoke-test-ingest-disabled/src/test/resources/rest-api-spec/test/ingest_mustache/10_ingest_disabled.yml
index 7a0cdcbef0786..c8fcebfba67ab 100644
--- a/qa/smoke-test-ingest-disabled/src/test/resources/rest-api-spec/test/ingest_mustache/10_ingest_disabled.yml
+++ b/qa/smoke-test-ingest-disabled/src/test/resources/rest-api-spec/test/ingest_mustache/10_ingest_disabled.yml
@@ -112,4 +112,3 @@
               _id:    test_id2
               pipeline: my_pipeline_1
           - f1: v2
-
diff --git a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/10_pipeline_with_mustache_templates.yml b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/10_pipeline_with_mustache_templates.yml
index e6a2a3d52e116..c043015281a9a 100644
--- a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/10_pipeline_with_mustache_templates.yml
+++ b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/10_pipeline_with_mustache_templates.yml
@@ -208,7 +208,7 @@
         id: 1
   - length: { _source: 2 }
   - match: { _source.do_nothing: "foo" }
-  - match: { _source.error: "processor first_processor [remove]: field [field_to_remove] not present as part of path [field_to_remove]" }
+  - match: { _source.error: "processor first_processor [remove]: field [field_to_remove] doesn't exist" }
 
 ---
 "Test rolling up json object arrays":
diff --git a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/50_script_processor_using_painless.yml b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/50_script_processor_using_painless.yml
index eaf6b24030a06..c58735f7862e6 100644
--- a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/50_script_processor_using_painless.yml
+++ b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/50_script_processor_using_painless.yml
@@ -102,4 +102,3 @@
   - match: { error.processor_type: "script" }
   - match: { error.type: "script_exception" }
   - match: { error.reason: "compile error" }
-
diff --git a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/60_pipeline_timestamp_date_mapping.yml b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/60_pipeline_timestamp_date_mapping.yml
index 0f514f2213492..d7f565f30c93d 100644
--- a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/60_pipeline_timestamp_date_mapping.yml
+++ b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/rest-api-spec/test/ingest/60_pipeline_timestamp_date_mapping.yml
@@ -34,4 +34,3 @@
         id: 1
         pipeline: "my_timely_pipeline"
         body: {}
-
diff --git a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/scripts/master.painless b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/scripts/master.painless
index 29880e8fd5f57..82f007e8e4dac 100644
--- a/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/scripts/master.painless
+++ b/qa/smoke-test-ingest-with-all-dependencies/src/test/resources/scripts/master.painless
@@ -1 +1 @@
-ctx.bytes_total = ctx.bytes_in + ctx.bytes_out
\ No newline at end of file
+ctx.bytes_total = ctx.bytes_in + ctx.bytes_out
diff --git a/qa/smoke-test-plugins/src/test/java/org/opensearch/smoketest/SmokeTestPluginsClientYamlTestSuiteIT.java b/qa/smoke-test-plugins/src/test/java/org/opensearch/smoketest/SmokeTestPluginsClientYamlTestSuiteIT.java
index a7e50601ad9df..a1c61ca97f877 100644
--- a/qa/smoke-test-plugins/src/test/java/org/opensearch/smoketest/SmokeTestPluginsClientYamlTestSuiteIT.java
+++ b/qa/smoke-test-plugins/src/test/java/org/opensearch/smoketest/SmokeTestPluginsClientYamlTestSuiteIT.java
@@ -49,4 +49,3 @@ public static Iterable<Object[]> parameters() throws Exception {
         return OpenSearchClientYamlSuiteTestCase.createParameters();
     }
 }
-
diff --git a/qa/smoke-test-plugins/src/test/resources/rest-api-spec/test/smoke_test_plugins/10_basic.yml b/qa/smoke-test-plugins/src/test/resources/rest-api-spec/test/smoke_test_plugins/10_basic.yml
index 6a92845a062aa..a4c8d4baabd1b 100644
--- a/qa/smoke-test-plugins/src/test/resources/rest-api-spec/test/smoke_test_plugins/10_basic.yml
+++ b/qa/smoke-test-plugins/src/test/resources/rest-api-spec/test/smoke_test_plugins/10_basic.yml
@@ -4,10 +4,10 @@
     - do:
         cluster.state: {}
 
-    # Get master node id
-    - set: { master_node: master }
+    # Get cluster-manager node id
+    - set: { cluster_manager_node: cluster_manager }
 
     - do:
         nodes.info: {}
 
-    - length:  { nodes.$master.plugins: ${expected.plugins.count}  }
+    - length:  { nodes.$cluster_manager.plugins: ${expected.plugins.count}  }
diff --git a/qa/translog-policy/src/test/java/org/opensearch/upgrades/TranslogPolicyIT.java b/qa/translog-policy/src/test/java/org/opensearch/upgrades/TranslogPolicyIT.java
index 0dc62b160ff3f..5f0f468898c47 100644
--- a/qa/translog-policy/src/test/java/org/opensearch/upgrades/TranslogPolicyIT.java
+++ b/qa/translog-policy/src/test/java/org/opensearch/upgrades/TranslogPolicyIT.java
@@ -35,7 +35,7 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.client.Request;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.index.IndexSettings;
diff --git a/qa/wildfly/build.gradle b/qa/wildfly/build.gradle
index 7cb08a9de6f08..5d37be47e782e 100644
--- a/qa/wildfly/build.gradle
+++ b/qa/wildfly/build.gradle
@@ -30,6 +30,7 @@
 
 import org.opensearch.gradle.Architecture
 import org.opensearch.gradle.VersionProperties
+import org.opensearch.gradle.test.TestTask
 
 apply plugin: 'war'
 apply plugin: 'opensearch.build'
@@ -39,25 +40,31 @@ apply plugin: 'opensearch.internal-distribution-download'
 testFixtures.useFixture()
 
 dependencies {
-  providedCompile 'javax.enterprise:cdi-api:1.2'
-  providedCompile 'org.jboss.spec.javax.annotation:jboss-annotations-api_1.2_spec:1.0.0.Final'
-  providedCompile 'org.jboss.spec.javax.ws.rs:jboss-jaxrs-api_2.0_spec:1.0.0.Final'
-  api('org.jboss.resteasy:resteasy-jackson2-provider:3.0.19.Final') {
-    exclude module: 'jackson-annotations'
-    exclude module: 'jackson-core'
-    exclude module: 'jackson-databind'
-    exclude module: 'jackson-jaxrs-json-provider'
+  providedCompile('jakarta.enterprise:jakarta.enterprise.cdi-api:4.0.1') {
+    exclude module: 'jakarta.annotation-api'
+  }
+  providedCompile 'jakarta.ws.rs:jakarta.ws.rs-api:3.1.0'
+  providedCompile "org.jboss.resteasy:resteasy-core:${versions.resteasy}"
+  providedCompile "org.jboss.resteasy:resteasy-core-spi:${versions.resteasy}"
+  api("org.jboss.resteasy:resteasy-jackson2-provider:${versions.resteasy}") {
+    exclude module: 'jakarta.activation-api'
+    exclude group: 'com.fasterxml.jackson'
+    exclude group: 'com.fasterxml.jackson.core'
+    exclude group: 'com.fasterxml.jackson.dataformat'
+    exclude group: 'com.fasterxml.jackson.module'
   }
   api "com.fasterxml.jackson.core:jackson-annotations:${versions.jackson}"
-  api "com.fasterxml.jackson.core:jackson-core:${versions.jackson}"
   api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
-  api "com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:${versions.jackson}"
-  api "com.fasterxml.jackson.jaxrs:jackson-jaxrs-base:${versions.jackson}"
-  api "com.fasterxml.jackson.module:jackson-module-jaxb-annotations:${versions.jackson}"
-  api "org.apache.logging.log4j:log4j-api:${versions.log4j}"
-  api "org.apache.logging.log4j:log4j-core:${versions.log4j}"
-  api project(path: ':client:rest-high-level')
-  testImplementation project(':test:framework')
+  api "com.fasterxml.jackson.jakarta.rs:jackson-jakarta-rs-base:${versions.jackson}"
+  api "com.fasterxml.jackson.jakarta.rs:jackson-jakarta-rs-json-provider:${versions.jackson}"
+  api "com.github.fge:json-patch:1.9"
+  api(project(path: ':client:rest-high-level')) {
+    exclude module: 'jakarta.annotation-api'
+  }
+  testImplementation "org.apache.logging.log4j:log4j-slf4j-impl:${versions.log4j}"
+  testImplementation(project(':test:framework')) {
+    exclude module: 'jakarta.annotation-api'
+  }
 }
 
 war {
@@ -81,7 +88,7 @@ dockerCompose {
   useComposeFiles = ['docker-compose.yml']
 }
 
-tasks.register("integTest", Test) {
+tasks.register("integTest", TestTask) {
   outputs.doNotCacheIf('Build cache is disabled for Docker tests') { true }
   maxParallelForks = '1'
   include '**/*IT.class'
diff --git a/qa/wildfly/docker-compose.yml b/qa/wildfly/docker-compose.yml
index 96f168ba3505c..b0f1609f01e72 100644
--- a/qa/wildfly/docker-compose.yml
+++ b/qa/wildfly/docker-compose.yml
@@ -2,7 +2,7 @@ version: '3.7'
 services:
 
   wildfly:
-    image: jboss/wildfly:18.0.1.Final
+    image: quay.io/wildfly/wildfly:28.0.1.Final-jdk11
     environment:
       JAVA_OPTS: -Dopensearch.uri=opensearch:9200 -Djboss.http.port=8080 -Djava.net.preferIPv4Stack=true
     volumes:
diff --git a/qa/wildfly/src/main/java/org/opensearch/wildfly/model/Employee.java b/qa/wildfly/src/main/java/org/opensearch/wildfly/model/Employee.java
index 5cf40ce941636..8f8d6635d568d 100644
--- a/qa/wildfly/src/main/java/org/opensearch/wildfly/model/Employee.java
+++ b/qa/wildfly/src/main/java/org/opensearch/wildfly/model/Employee.java
@@ -34,12 +34,8 @@
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
-import javax.ws.rs.Consumes;
-import javax.ws.rs.core.MediaType;
-
 import java.util.List;
 
-@Consumes(MediaType.APPLICATION_JSON)
 public class Employee {
 
     @JsonProperty(value = "first_name")
diff --git a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientActivator.java b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientActivator.java
index bf91346933e02..14b8cd6730531 100644
--- a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientActivator.java
+++ b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientActivator.java
@@ -32,18 +32,10 @@
 
 package org.opensearch.wildfly.transport;
 
-import javax.ws.rs.ApplicationPath;
-import javax.ws.rs.core.Application;
-
-import java.util.Collections;
-import java.util.Set;
+import jakarta.ws.rs.ApplicationPath;
+import jakarta.ws.rs.core.Application;
 
 @ApplicationPath("/transport")
 public class RestHighLevelClientActivator extends Application {
 
-    @Override
-    public Set<Class<?>> getClasses() {
-        return Collections.singleton(RestHighLevelClientEmployeeResource.class);
-    }
-
 }
diff --git a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientEmployeeResource.java b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientEmployeeResource.java
index da751df3fbeee..d2bc0a81768d7 100644
--- a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientEmployeeResource.java
+++ b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientEmployeeResource.java
@@ -38,17 +38,9 @@
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.client.RequestOptions;
 import org.opensearch.client.RestHighLevelClient;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.wildfly.model.Employee;
 
-import javax.inject.Inject;
-import javax.ws.rs.GET;
-import javax.ws.rs.PUT;
-import javax.ws.rs.Path;
-import javax.ws.rs.PathParam;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -56,6 +48,16 @@
 import java.util.Map;
 import java.util.Objects;
 
+import jakarta.inject.Inject;
+import jakarta.ws.rs.Consumes;
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.PUT;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.PathParam;
+import jakarta.ws.rs.Produces;
+import jakarta.ws.rs.core.MediaType;
+import jakarta.ws.rs.core.Response;
+
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 
 @Path("/employees")
@@ -88,6 +90,7 @@ public Response getEmployeeById(final @PathParam("id") Long id) throws IOExcepti
 
     @PUT
     @Path("/{id}")
+    @Consumes(MediaType.APPLICATION_JSON)
     @Produces(MediaType.APPLICATION_JSON)
     public Response putEmployeeById(final @PathParam("id") Long id, final Employee employee) throws URISyntaxException, IOException {
         Objects.requireNonNull(id);
diff --git a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientProducer.java b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientProducer.java
index f85c3efcbb6e8..a6e2f0e10491c 100644
--- a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientProducer.java
+++ b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelClientProducer.java
@@ -38,9 +38,10 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
 
-import javax.enterprise.inject.Produces;
 import java.nio.file.Path;
 
+import jakarta.enterprise.inject.Produces;
+
 @SuppressWarnings("unused")
 public final class RestHighLevelClientProducer {
 
diff --git a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelJacksonJsonProvider.java b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelJacksonJsonProvider.java
index 604d975f53280..7f27e69813971 100644
--- a/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelJacksonJsonProvider.java
+++ b/qa/wildfly/src/main/java/org/opensearch/wildfly/transport/RestHighLevelJacksonJsonProvider.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.wildfly.transport;
 
+import jakarta.ws.rs.ext.Provider;
 import org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider;
 
-import javax.ws.rs.ext.Provider;
-
 @Provider
 public class RestHighLevelJacksonJsonProvider extends ResteasyJackson2Provider {
 
diff --git a/qa/wildfly/src/main/resources/log4j2.properties b/qa/wildfly/src/main/resources/log4j2.properties
deleted file mode 100644
index 4fd5d69daf65b..0000000000000
--- a/qa/wildfly/src/main/resources/log4j2.properties
+++ /dev/null
@@ -1,20 +0,0 @@
-#
-# SPDX-License-Identifier: Apache-2.0
-#
-# The OpenSearch Contributors require contributions made to
-# this file be licensed under the Apache-2.0 license or a
-# compatible open source license.
-#
-# Modifications Copyright OpenSearch Contributors. See
-# GitHub history for details.
-#
-
-status = error
-
-appender.console.type = Console
-appender.console.name = console
-appender.console.layout.type = PatternLayout
-appender.console.layout.pattern = [%d{ISO8601}][%-5p][%-25c{1.}] %marker%m%n
-
-rootLogger.level = info
-rootLogger.appenderRef.console.ref = console
diff --git a/qa/wildfly/src/main/webapp/WEB-INF/jboss-deployment-structure.xml b/qa/wildfly/src/main/webapp/WEB-INF/jboss-deployment-structure.xml
index 7191bfe1268aa..a08090100989a 100644
--- a/qa/wildfly/src/main/webapp/WEB-INF/jboss-deployment-structure.xml
+++ b/qa/wildfly/src/main/webapp/WEB-INF/jboss-deployment-structure.xml
@@ -1,9 +1,6 @@
 <jboss-deployment-structure>
     <deployment>
         <exclusions>
-            <module name="com.fasterxml.jackson.core.jackson-core" />
-            <module name="com.fasterxml.jackson.core.jackson-databind" />
-            <module name="com.fasterxml.jackson.jaxrs.jackson-jaxrs-json-provider" />
             <module name="org.jboss.resteasy.resteasy-jackson2-provider" />
         </exclusions>
     </deployment>
diff --git a/qa/wildfly/src/test/java/org/opensearch/wildfly/WildflyIT.java b/qa/wildfly/src/test/java/org/opensearch/wildfly/WildflyIT.java
index 7961ca69c2d29..ab24dfaddd893 100644
--- a/qa/wildfly/src/test/java/org/opensearch/wildfly/WildflyIT.java
+++ b/qa/wildfly/src/test/java/org/opensearch/wildfly/WildflyIT.java
@@ -45,10 +45,10 @@
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.apache.lucene.tests.util.TestRuleLimitSysouts;
 import org.opensearch.cluster.ClusterModule;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.net.URI;
diff --git a/release-notes/opensearch.release-notes-1.0.0-rc1.md b/release-notes/opensearch.release-notes-1.0.0-rc1.md
index 2223d732abb98..205873fd282b2 100644
--- a/release-notes/opensearch.release-notes-1.0.0-rc1.md
+++ b/release-notes/opensearch.release-notes-1.0.0-rc1.md
@@ -411,5 +411,3 @@
 
 
     Signed-off-by: Abbas Hussain &lt;abbas_10690@yahoo.com&gt;
-
-
diff --git a/release-notes/opensearch.release-notes-1.1.0.md b/release-notes/opensearch.release-notes-1.1.0.md
index 0545e106a15a5..ba5a5d4c95c60 100644
--- a/release-notes/opensearch.release-notes-1.1.0.md
+++ b/release-notes/opensearch.release-notes-1.1.0.md
@@ -386,5 +386,3 @@
 
 
     Signed-off-by: Sooraj Sinha &lt;soosinha@amazon.com&gt;
-
-
diff --git a/release-notes/opensearch.release-notes-1.2.0.md b/release-notes/opensearch.release-notes-1.2.0.md
index 86860e5f872da..d7c75f3c0eaf2 100644
--- a/release-notes/opensearch.release-notes-1.2.0.md
+++ b/release-notes/opensearch.release-notes-1.2.0.md
@@ -458,4 +458,3 @@
 
 
     Signed-off-by: Nicholas Walter Knize &lt;nknize@apache.org&gt;
-
diff --git a/release-notes/opensearch.release-notes-1.2.4.md b/release-notes/opensearch.release-notes-1.2.4.md
index dc2852a102c44..dc0bce20a2a00 100644
--- a/release-notes/opensearch.release-notes-1.2.4.md
+++ b/release-notes/opensearch.release-notes-1.2.4.md
@@ -72,5 +72,3 @@
     
     
     Signed-off-by: dblock &lt;dblock@amazon.com&gt;
-
-
diff --git a/release-notes/opensearch.release-notes-1.3.0.md b/release-notes/opensearch.release-notes-1.3.0.md
index 62c5be8413943..7dd71fa47b72f 100644
--- a/release-notes/opensearch.release-notes-1.3.0.md
+++ b/release-notes/opensearch.release-notes-1.3.0.md
@@ -1295,5 +1295,3 @@
     [Nick Knize](mailto:nknize@apache.org) - Thu, 4 Nov 2021 14:46:57 -0500
 
     Signed-off-by: Nicholas Walter Knize &lt;nknize@apache.org&gt;
-
-
diff --git a/release-notes/opensearch.release-notes-2.0.0.md b/release-notes/opensearch.release-notes-2.0.0.md
new file mode 100644
index 0000000000000..ab38069bbf67d
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.0.0.md
@@ -0,0 +1,210 @@
+## 2022-05-19 Version 2.0.0 Release Notes
+
+### Breaking Changes in 2.0
+
+#### Remove Mapping types
+* [Type removal] Remove redundant _type in pipeline simulate action  ([#3371](https://github.com/opensearch-project/OpenSearch/pull/3371))
+* [Type removal] Remove _type deprecation from script and conditional processor  ([#3239](https://github.com/opensearch-project/OpenSearch/pull/3239))
+* [Type removal] Remove _type from _bulk yaml test, scripts, unused constants  ([#3372](https://github.com/opensearch-project/OpenSearch/pull/3372))
+* [Type removal] _type removal from mocked responses of scroll hit tests  ([#3377](https://github.com/opensearch-project/OpenSearch/pull/3377))
+* [Remove] TypeFieldMapper  ([#3196](https://github.com/opensearch-project/OpenSearch/pull/3196))
+* [Type Removal] Remove TypeFieldMapper usage, remove support of `_type` in searches and from LeafFieldsLookup  ([#3016](https://github.com/opensearch-project/OpenSearch/pull/3016))
+* [Type removal] Remove _type support in NOOP bulk indexing from client benchmark ([#3076](https://github.com/opensearch-project/OpenSearch/pull/3076))
+* [Type removal] Remove deprecation warning on use of _type in doc scripts ([#2564](https://github.com/opensearch-project/OpenSearch/pull/2564))
+* [Remove] AliasesExistAction ([#3149](https://github.com/opensearch-project/OpenSearch/pull/3149))
+* [Remove] TypesExist Action ([#3139](https://github.com/opensearch-project/OpenSearch/pull/3139))
+* [Remove] Type from nested fields using new metadata field mapper([#3004](https://github.com/opensearch-project/OpenSearch/pull/3004))
+* [Remove] types from rest-api-spec endpoints ([#2689](https://github.com/opensearch-project/OpenSearch/pull/2689))
+* [Remove] Types from PutIndexTemplateRequest and builder to reduce mapping to a string ([#2510](https://github.com/opensearch-project/OpenSearch/pull/2510))
+* [Remove] Type from Percolate query API ([#2490](https://github.com/opensearch-project/OpenSearch/pull/2490))
+* [Remove] types from CreateIndexRequest and companion Builder's mapping method ([#2498](https://github.com/opensearch-project/OpenSearch/pull/2498))
+* [Remove] Type from PutIndexTemplateRequest and PITRB ([#2497](https://github.com/opensearch-project/OpenSearch/pull/2497))
+* [Remove] Type metadata from ingest documents ([#2491](https://github.com/opensearch-project/OpenSearch/pull/2491))
+* [Remove] type from CIR.mapping and CIRB.mapping ([#2478](https://github.com/opensearch-project/OpenSearch/pull/2478))
+* [Remove] types based addMapping method from CreateIndexRequest and Builder ([#2460](https://github.com/opensearch-project/OpenSearch/pull/2460))
+* [Remove] type from TaskResults index and IndexMetadata.getMappings ([#2469](https://github.com/opensearch-project/OpenSearch/pull/2469))
+* [Remove] Type query ([#2448](https://github.com/opensearch-project/OpenSearch/pull/2448))
+* [Remove] Type from TermsLookUp ([#2459](https://github.com/opensearch-project/OpenSearch/pull/2459))
+* [Remove] types from Uid and remaining types/Uid from translog ([#2450](https://github.com/opensearch-project/OpenSearch/pull/2450))
+* [Remove] types from translog ([#2439](https://github.com/opensearch-project/OpenSearch/pull/2439))
+* [Remove] Multiple Types from IndexTemplateMetadata ([#2400](https://github.com/opensearch-project/OpenSearch/pull/2400))
+* Remove type mapping from document index API ([#2026](https://github.com/opensearch-project/OpenSearch/pull/2026))
+* [Remove] Type mapping parameter from document update API ([#2204](https://github.com/opensearch-project/OpenSearch/pull/2204))
+* [Remove] Types from DocWrite Request and Response ([#2239](https://github.com/opensearch-project/OpenSearch/pull/2239))
+* [Remove] Types from GET/MGET ([#2168](https://github.com/opensearch-project/OpenSearch/pull/2168))
+* [Remove] types from SearchHit and Explain API ([#2205](https://github.com/opensearch-project/OpenSearch/pull/2205))
+* [Remove] type support from Bulk API ([#2215](https://github.com/opensearch-project/OpenSearch/pull/2215))
+* Remove type end-points from no-op bulk and search action ([#2261](https://github.com/opensearch-project/OpenSearch/pull/2261))
+* Remove type end-points from search and related APIs ([#2263](https://github.com/opensearch-project/OpenSearch/pull/2263))
+* [Remove] Type mapping end-points from RestMultiSearchTemplateAction ([#2433](https://github.com/opensearch-project/OpenSearch/pull/2433))
+* Removes type mappings from mapping APIs ([#2238](https://github.com/opensearch-project/OpenSearch/pull/2238))
+* Remove type end-points from count action ([#2379](https://github.com/opensearch-project/OpenSearch/pull/2379))
+* Remove type from validate query API ([#2255](https://github.com/opensearch-project/OpenSearch/pull/2255))
+* [Remove] Type parameter from TermVectors API ([#2104](https://github.com/opensearch-project/OpenSearch/pull/2104))
+* Remove inclue_type_name parameter from rest api spec ([#2410](https://github.com/opensearch-project/OpenSearch/pull/2410))
+* [Remove] include_type_name from HLRC ([#2397](https://github.com/opensearch-project/OpenSearch/pull/2397))
+* [Remove] Type mappings from GeoShapeQueryBuilder ([#2322](https://github.com/opensearch-project/OpenSearch/pull/2322))
+* [Remove] types from PutMappingRequest ([#2335](https://github.com/opensearch-project/OpenSearch/pull/2335))
+* [Remove] deprecated getMapping API from IndicesClient ([#2262](https://github.com/opensearch-project/OpenSearch/pull/2262))
+* [Remove] remaining type usage in Client and AbstractClient ([#2258](https://github.com/opensearch-project/OpenSearch/pull/2258))
+* [Remove] Type from Client.prepare(Index,Delete,Update) ([#2253](https://github.com/opensearch-project/OpenSearch/pull/2253))
+* [Remove] Type Specific Index Stats ([#2198](https://github.com/opensearch-project/OpenSearch/pull/2198))
+* [Remove] Type from Search Internals ([#2109](https://github.com/opensearch-project/OpenSearch/pull/2109))
+
+#### Upgrades
+* [Upgrade] Lucene 9.1 release ([#2560](https://github.com/opensearch-project/OpenSearch/pull/2560))
+* [Upgrade] ICU4j from 68.2 to 70.1 ([#2504](https://github.com/opensearch-project/OpenSearch/pull/2504))
+
+#### Deprecations
+* Deprecate setting 'cluster.no_master_block' and introduce the alternative setting 'cluster.no_cluster_manager_block' ([#2453](https://github.com/opensearch-project/OpenSearch/pull/2453))
+* Deprecate setting 'cluster.service.slow_master_task_logging_threshold' and introduce the alternative setting 'cluster.service.slow_cluster_manager_task_logging_threshold' ([#2451](https://github.com/opensearch-project/OpenSearch/pull/2451))
+* Deprecate setting 'cluster.initial_master_nodes' and introduce the alternative setting 'cluster.initial_cluster_manager_nodes' ([#2463](https://github.com/opensearch-project/OpenSearch/pull/2463))
+* Deprecated reserved node id '_must_join_elected_master_' that used by DetachClusterCommand and replace with '_must_join_elected_cluster_manager_' ([#3138](https://github.com/opensearch-project/OpenSearch/pull/3138))
+
+### Security Fixes
+* [CVE-2020-36518] Update jackson-databind to 2.13.2.2 ([#2599](https://github.com/opensearch-project/OpenSearch/pull/2599))
+
+### Features/Enhancements
+* Removing hard coded value of max concurrent shard requests ([#3364](https://github.com/opensearch-project/OpenSearch/pull/3364))
+* Update generated ANTLR lexer/parser to match runtime version ([#3297](https://github.com/opensearch-project/OpenSearch/pull/3297))
+* Rename BecomeMasterTask to BecomeClusterManagerTask in JoinTaskExecutor  ([#3099](https://github.com/opensearch-project/OpenSearch/pull/3099))
+* Replace 'master' terminology with 'cluster manager' in log messages in 'server/src/main' directory - Part 2 ([#3174](https://github.com/opensearch-project/OpenSearch/pull/3174))
+* Remove deprecation warning of using REST API request parameter 'master_timeout' ([#2920](https://github.com/opensearch-project/OpenSearch/pull/2920))
+* Add deprecated API for creating History Ops Snapshot from translog ([#2886](https://github.com/opensearch-project/OpenSearch/pull/2886))
+* Add request parameter 'cluster_manager_timeout' and deprecate 'master_timeout' - in Ingest APIs and Script APIs ([#2682](https://github.com/opensearch-project/OpenSearch/pull/2682))
+* Change deprecation message for API parameter value 'master_node' of parameter 'metric' ([#2880](https://github.com/opensearch-project/OpenSearch/pull/2880))
+* Add request parameter 'cluster_manager_timeout' and deprecate 'master_timeout' - in Snapshot APIs ([#2680](https://github.com/opensearch-project/OpenSearch/pull/2680))
+* Add request parameter 'cluster_manager_timeout' and deprecate 'master_timeout' - in Index Template APIs ([#2678](https://github.com/opensearch-project/OpenSearch/pull/2678))
+* Change deprecation message for REST API parameter 'master_timeout' to specify the version of removal  ([#2863](https://github.com/opensearch-project/OpenSearch/pull/2863))
+* Decouple IndexSettings from IncludeExclude ([#2860](https://github.com/opensearch-project/OpenSearch/pull/2860))
+* Remove endpoint_suffix dependency on account key ([#2485](https://github.com/opensearch-project/OpenSearch/pull/2485))
+* Replace remaining 'blacklist' with 'denylist' in internal class and method names ([#2784](https://github.com/opensearch-project/OpenSearch/pull/2784))
+* Make discovered_master field optional on the client to support compatibility for opensearch client with odfe ([#2641](https://github.com/opensearch-project/OpenSearch/pull/2641))
+* Add request parameter 'cluster_manager_timeout' and deprecate 'master_timeout' - in Index APIs except index template APIs  ([#2660](https://github.com/opensearch-project/OpenSearch/pull/2660))
+* Add request parameter 'cluster_manager_timeout' and deprecate 'master_timeout' - in Cluster APIs ([#2658](https://github.com/opensearch-project/OpenSearch/pull/2658))
+* Make Rest-High-Rest-Level tests allow deprecation warning temporarily, during deprecation of request parameter 'master_timeout' ([#2702](https://github.com/opensearch-project/OpenSearch/pull/2702))
+* Add request parameter 'cluster_manager_timeout' as the alternative for 'master_timeout', and deprecate 'master_timeout' - in CAT APIs ([#2717](https://github.com/opensearch-project/OpenSearch/pull/2717))
+* Add mapping method back referenced in other repos ([#2636](https://github.com/opensearch-project/OpenSearch/pull/2636))
+* Replaced "master" terminology in Log message ([#2575](https://github.com/opensearch-project/OpenSearch/pull/2575))
+* Introduce QueryPhaseSearcher extension point (SearchPlugin) ([#1931](https://github.com/opensearch-project/OpenSearch/pull/1931))
+* Support for geo_bounding_box queries on geo_shape fields ([#2506](https://github.com/opensearch-project/OpenSearch/pull/2506))
+* Updating repository commons logging version ([#2541](https://github.com/opensearch-project/OpenSearch/pull/2541))
+* Support for geo_distance queries on geo_shape fields ([#2516](https://github.com/opensearch-project/OpenSearch/pull/2516))
+* Add 'cluster_manager_node' into ClusterState Metric as an alternative to 'master_node' ([#2415](https://github.com/opensearch-project/OpenSearch/pull/2415))
+* Add a new node role 'cluster_manager' as the alternative for 'master' role and deprecate 'master' role ([#2424](https://github.com/opensearch-project/OpenSearch/pull/2424))
+* Replace 'master' with 'cluster_manager' in 'GET Cat Nodes' API ([#2441](https://github.com/opensearch-project/OpenSearch/pull/2441))
+* Replace 'discovered_master' with 'discovered_cluster_manager' in 'GET Cat Health' API ([#2438](https://github.com/opensearch-project/OpenSearch/pull/2438))
+* Add a field discovered_cluster_manager in get cluster health api ([#2437](https://github.com/opensearch-project/OpenSearch/pull/2437))
+* Add request parameter 'cluster_manager_timeout' as the alternative for 'master_timeout', and deprecate 'master_timeout' - in CAT Nodes API ([#2435](https://github.com/opensearch-project/OpenSearch/pull/2435))
+* Add a new REST API endpoint 'GET _cat/cluster_manager' as the replacement of 'GET _cat/master' ([#2404](https://github.com/opensearch-project/OpenSearch/pull/2404))
+* Add default for EnginePlugin.getEngineFactory ([#2419](https://github.com/opensearch-project/OpenSearch/pull/2419))
+
+### Bug Fixes
+* Fixing PublishTests tests (running against unclean build folders) ([#3253](https://github.com/opensearch-project/OpenSearch/pull/3253))
+* Fixing Scaled float field mapper to respect ignoreMalformed setting ([#2918](https://github.com/opensearch-project/OpenSearch/pull/2918))
+* Fixing plugin installation URL to consume build qualifier ([#3193](https://github.com/opensearch-project/OpenSearch/pull/3193))
+* Fix minimum index compatibility error message  ([#3159](https://github.com/opensearch-project/OpenSearch/pull/3159))
+* Added explicit 'null' check for response listener to prevent obscure NullPointerException issues  ([#3048](https://github.com/opensearch-project/OpenSearch/pull/3048))
+* Adding a null pointer check to fix index_prefix query ([#2879](https://github.com/opensearch-project/OpenSearch/pull/2879))
+* Bugfix to guard against stack overflow errors caused by very large reg-ex input ([#2816](https://github.com/opensearch-project/OpenSearch/pull/2816))
+* Fix InboundDecoder version compat check  ([#2570](https://github.com/opensearch-project/OpenSearch/pull/2570))
+* ignore_malformed parameter on ip_range data_type throws mapper_parsing_exception ([#2429](https://github.com/opensearch-project/OpenSearch/pull/2429))
+* Discrepancy in result from _validate/query API and actual query validity ([#2416](https://github.com/opensearch-project/OpenSearch/pull/2416))
+
+### Build & Infrastructure
+* Allow to configure POM for ZIP publication  ([#3252](https://github.com/opensearch-project/OpenSearch/pull/3252))
+* Gradle plugin `opensearch.pluginzip` Add implicit dependency. ([#3189](https://github.com/opensearch-project/OpenSearch/pull/3189))
+* Gradle custom java zippublish plugin ([#2988](https://github.com/opensearch-project/OpenSearch/pull/2988))
+* Added Adoptium JDK8 support and updated DistroTestPlugin JDK version used by Gradle  ([#3324](https://github.com/opensearch-project/OpenSearch/pull/3324))
+* Update bundled JDK to 17.0.3+7  ([#3093](https://github.com/opensearch-project/OpenSearch/pull/3093))
+* Use G1GC on JDK11+ ([#2964](https://github.com/opensearch-project/OpenSearch/pull/2964))
+* Removed java11 source folders since JDK-11 is the baseline now ([#2898](https://github.com/opensearch-project/OpenSearch/pull/2898))
+* Changed JAVA_HOME to jdk-17  ([#2656](https://github.com/opensearch-project/OpenSearch/pull/2656))
+* Fix build-tools/reaper source/target compatibility to be JDK-11  ([#2596](https://github.com/opensearch-project/OpenSearch/pull/2596))
+* Adding workflow to create documentation related issues in documentation-website repo ([#2929](https://github.com/opensearch-project/OpenSearch/pull/2929))
+* Fix issue that deprecated setting 'cluster.initial_master_nodes' is not identified in node bootstrap check  ([#2779](https://github.com/opensearch-project/OpenSearch/pull/2779))
+* Replace blacklist in Gradle build environment configuration ([#2752](https://github.com/opensearch-project/OpenSearch/pull/2752))
+* Update ThirdPartyAuditTask to check for and list pointless exclusions. ([#2760](https://github.com/opensearch-project/OpenSearch/pull/2760))
+* Add Shadow jar publication to lang-painless module.  ([#2681](https://github.com/opensearch-project/OpenSearch/pull/2681))
+* Add 1.3.2 to main causing gradle check failures  ([#2679](https://github.com/opensearch-project/OpenSearch/pull/2679))
+* Added jenkinsfile to run gradle check in OpenSearch  ([#2166](https://github.com/opensearch-project/OpenSearch/pull/2166))
+* Gradle check retry  ([#2638](https://github.com/opensearch-project/OpenSearch/pull/2638))
+* Override Default Distribution Download Url with Custom Distribution Url when it is passed from Plugin ([#2420](https://github.com/opensearch-project/OpenSearch/pull/2420))
+
+### Documentation
+* [Javadocs] add remaining internal classes and reenable missingJavadoc on server ([#3296](https://github.com/opensearch-project/OpenSearch/pull/3296))
+* [Javadocs] add to o.o.cluster  ([#3170](https://github.com/opensearch-project/OpenSearch/pull/3170))
+* [Javadocs] add to o.o.bootstrap, cli, and client  ([#3163](https://github.com/opensearch-project/OpenSearch/pull/3163))
+* [Javadocs] add to o.o.search.rescore,searchafter,slice, sort, and suggest ([#3264](https://github.com/opensearch-project/OpenSearch/pull/3264))
+* [Javadocs] add to o.o.transport ([#3220](https://github.com/opensearch-project/OpenSearch/pull/3220))
+* [Javadocs] add to o.o.action, index, and transport ([#3277](https://github.com/opensearch-project/OpenSearch/pull/3277))
+* [Javadocs] add to internal classes in o.o.http, indices, and search ([#3288](https://github.com/opensearch-project/OpenSearch/pull/3288))
+* [Javadocs] Add to remaining o.o.action classes ([#3182](https://github.com/opensearch-project/OpenSearch/pull/3182))
+* [Javadocs] add to o.o.rest, snapshots, and tasks packages ([#3219](https://github.com/opensearch-project/OpenSearch/pull/3219))
+* [Javadocs] add to o.o.common ([#3289](https://github.com/opensearch-project/OpenSearch/pull/3289))
+* [Javadocs] add to o.o.dfs,fetch,internal,lookup,profile, and query packages ([#3261](https://github.com/opensearch-project/OpenSearch/pull/3261))
+* [Javadocs] add to o.o.search.aggs, builder, and collapse packages ([#3254](https://github.com/opensearch-project/OpenSearch/pull/3254))
+* [Javadocs] add to o.o.index and indices  ([#3209](https://github.com/opensearch-project/OpenSearch/pull/3209))
+* [Javadocs] add to o.o.monitor,persistance,plugins,repo,script,threadpool,usage,watcher ([#3186](https://github.com/opensearch-project/OpenSearch/pull/3186))
+* [Javadocs] Add to o.o.disovery, env, gateway, http, ingest, lucene and node pkgs  ([#3185](https://github.com/opensearch-project/OpenSearch/pull/3185))
+* [Javadocs] add to o.o.action.admin ([#3155](https://github.com/opensearch-project/OpenSearch/pull/3155))
+* [Javadocs] Add missing package-info.java files to server ([#3128](https://github.com/opensearch-project/OpenSearch/pull/3128))
+
+### Maintenance
+* Bump re2j from 1.1 to 1.6 in /plugins/repository-hdfs ([#3337](https://github.com/opensearch-project/OpenSearch/pull/3337))
+* Bump google-oauth-client from 1.33.1 to 1.33.2 in /plugins/discovery-gce ([#2828](https://github.com/opensearch-project/OpenSearch/pull/2828))
+* Bump protobuf-java-util from 3.19.3 to 3.20.0 in /plugins/repository-gcs ([#2834](https://github.com/opensearch-project/OpenSearch/pull/2834))
+* Bump cdi-api from 1.2 to 2.0 in /qa/wildfly ([#2835](https://github.com/opensearch-project/OpenSearch/pull/2835))
+* Bump azure-core from 1.26.0 to 1.27.0 in /plugins/repository-azure ([#2837](https://github.com/opensearch-project/OpenSearch/pull/2837))
+* Bump asm-analysis from 9.2 to 9.3 in /test/logger-usage  ([#2829](https://github.com/opensearch-project/OpenSearch/pull/2829))
+* Bump protobuf-java from 3.19.3 to 3.20.0 in /plugins/repository-hdfs  ([#2836](https://github.com/opensearch-project/OpenSearch/pull/2836))
+* Bump joni from 2.1.41 to 2.1.43 in /libs/grok ([#2832](https://github.com/opensearch-project/OpenSearch/pull/2832))
+* Bump geoip2 from 2.16.1 to 3.0.1 in /modules/ingest-geoip  ([#2646](https://github.com/opensearch-project/OpenSearch/pull/2646))
+* Bump jettison from 1.1 to 1.4.1 in /plugins/discovery-azure-classic ([#2614](https://github.com/opensearch-project/OpenSearch/pull/2614))
+* Bump google-oauth-client from 1.31.0 to 1.33.1 in /plugins/repository-gcs  ([#2616](https://github.com/opensearch-project/OpenSearch/pull/2616))
+* Bump jboss-annotations-api_1.2_spec in /qa/wildfly  ([#2615](https://github.com/opensearch-project/OpenSearch/pull/2615))
+* Bump forbiddenapis in /buildSrc/src/testKit/thirdPartyAudit  ([#2611](https://github.com/opensearch-project/OpenSearch/pull/2611))
+* Bump json-schema-validator from 1.0.67 to 1.0.68 in /buildSrc ([#2610](https://github.com/opensearch-project/OpenSearch/pull/2610))
+* Bump htrace-core4 from 4.1.0-incubating to 4.2.0-incubating in /plugins/repository-hdfs  ([#2618](https://github.com/opensearch-project/OpenSearch/pull/2618))
+* Bump asm-tree from 7.2 to 9.2 in /modules/lang-painless  ([#2617](https://github.com/opensearch-project/OpenSearch/pull/2617))
+* Bump antlr4 from 4.5.3 to 4.9.3 in /modules/lang-painless ([#2537](https://github.com/opensearch-project/OpenSearch/pull/2537))
+* Bump commons-lang3 from 3.7 to 3.12.0 in /plugins/repository-hdfs ([#2552](https://github.com/opensearch-project/OpenSearch/pull/2552))
+* Bump gson from 2.8.9 to 2.9.0 in /plugins/repository-gcs ([#2550](https://github.com/opensearch-project/OpenSearch/pull/2550))
+* Bump google-oauth-client from 1.31.0 to 1.33.1 in /plugins/discovery-gce ([#2524](https://github.com/opensearch-project/OpenSearch/pull/2524))
+* Bump google-cloud-core from 1.93.3 to 2.5.10 in /plugins/repository-gcs ([#2536](https://github.com/opensearch-project/OpenSearch/pull/2536))
+* Bump wiremock-jre8-standalone from 2.23.2 to 2.32.0 in /buildSrc ([#2525](https://github.com/opensearch-project/OpenSearch/pull/2525))
+* Bump com.gradle.enterprise from 3.8.1 to 3.9 ([#2523](https://github.com/opensearch-project/OpenSearch/pull/2523))
+* Bump commons-io from 2.7 to 2.11.0 in /plugins/discovery-azure-classic ([#2527](https://github.com/opensearch-project/OpenSearch/pull/2527))
+* Bump asm-analysis from 7.1 to 9.2 in /test/logger-usage ([#2273](https://github.com/opensearch-project/OpenSearch/pull/2273))
+* Bump asm-commons from 7.2 to 9.2 in /modules/lang-painless ([#2234](https://github.com/opensearch-project/OpenSearch/pull/2234))
+* Bump jna from 5.5.0 to 5.10.0 in /buildSrc ([#2512](https://github.com/opensearch-project/OpenSearch/pull/2512))
+* Bump jsr305 from 1.3.9 to 3.0.2 in /plugins/discovery-gce ([#2137](https://github.com/opensearch-project/OpenSearch/pull/2137))
+* Bump json-schema-validator from 1.0.36 to 1.0.67 in /buildSrc ([#2454](https://github.com/opensearch-project/OpenSearch/pull/2454))
+* Bump woodstox-core from 6.1.1 to 6.2.8 in /plugins/repository-azure ([#2456](https://github.com/opensearch-project/OpenSearch/pull/2456))
+* Bump commons-lang3 from 3.4 to 3.12.0 in /plugins/repository-azure ([#2455](https://github.com/opensearch-project/OpenSearch/pull/2455))
+* Update azure-storage-blob to 12.15.0 ([#2774](https://github.com/opensearch-project/OpenSearch/pull/2774))
+* Move Jackson-databind to 2.13.2 ([#2548](https://github.com/opensearch-project/OpenSearch/pull/2548))
+* Add trademark notice ([#2473](https://github.com/opensearch-project/OpenSearch/pull/2473))
+* adds ToC ([#2546](https://github.com/opensearch-project/OpenSearch/pull/2546))
+* Sync maintainers with actual permissions. ([#3127](https://github.com/opensearch-project/OpenSearch/pull/3127))
+
+### Refactoring
+* [Remove] remaining AllFieldMapper references ([#3007](https://github.com/opensearch-project/OpenSearch/pull/3007))
+* Clear up some confusing code in IndexShardHotSpotTests ([#1534](https://github.com/opensearch-project/OpenSearch/pull/1534))
+* [Remove] ShrinkAction, ShardUpgradeRequest, UpgradeSettingsRequestBuilder ([#3169](https://github.com/opensearch-project/OpenSearch/pull/3169))
+* [Rename] ESTestCase stragglers to OpenSearchTestCase ([#3053](https://github.com/opensearch-project/OpenSearch/pull/3053))
+* [Remove] MainResponse version override cluster setting ([#3031](https://github.com/opensearch-project/OpenSearch/pull/3031))
+* [Version] Don't spoof major for 3.0+ clusters ([#2722](https://github.com/opensearch-project/OpenSearch/pull/2722))
+* Centralize codes related to 'master_timeout' deprecation for eaiser removal - in CAT Nodes API ([#2670](https://github.com/opensearch-project/OpenSearch/pull/2670))
+* Rename reference to project OpenSearch was forked from ([#2483](https://github.com/opensearch-project/OpenSearch/pull/2483))
+* Remove the IndexCommitRef class ([#2421](https://github.com/opensearch-project/OpenSearch/pull/2421))
+* Refactoring gated and ref-counted interfaces and their implementations ([#2396](https://github.com/opensearch-project/OpenSearch/pull/2396))
+* [Refactor] LuceneChangesSnapshot to use accurate ops history ([#2452](https://github.com/opensearch-project/OpenSearch/pull/2452))
+
+### Tests
+* Add type mapping removal bwc tests for indexing, searching, snapshots ([#2901](https://github.com/opensearch-project/OpenSearch/pull/2901))
+* Removing SLM check in tests for OpenSearch versions ([#2604](https://github.com/opensearch-project/OpenSearch/pull/2604))
+* [Unmute] NumberFieldTypeTests ([#2531](https://github.com/opensearch-project/OpenSearch/pull/2531))
+* Use Hamcrest matchers and assertThat() in ReindexRenamedSettingTests ([#2503](https://github.com/opensearch-project/OpenSearch/pull/2503))
+* [Unmute] IndexPrimaryRelocationIT ([#2488](https://github.com/opensearch-project/OpenSearch/pull/2488))
+* Fixing PluginsServiceTests (post Lucene 9 update) ([#2484](https://github.com/opensearch-project/OpenSearch/pull/2484))
diff --git a/release-notes/opensearch.release-notes-2.0.1.md b/release-notes/opensearch.release-notes-2.0.1.md
new file mode 100644
index 0000000000000..e2918d14a055c
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.0.1.md
@@ -0,0 +1,9 @@
+## 2022-06-15 Version 2.0.1 Release Notes
+
+### Bug Fixes
+* Fixing the Node Sniffer RestClient support for OpenSearch 2.x ([#3522](https://github.com/opensearch-project/OpenSearch/pull/3522))
+* Adding MainResponse version override cluster setting ([#3536](https://github.com/opensearch-project/OpenSearch/pull/3536))
+
+### Tests
+* Fixing Docker test for Ubuntu ([#3465](https://github.com/opensearch-project/OpenSearch/pull/3465))
+* [Type removal] Fixing the cluster upgrade backward compatibility test ([#3531](https://github.com/opensearch-project/OpenSearch/pull/3531))
diff --git a/release-notes/opensearch.release-notes-2.1.0.md b/release-notes/opensearch.release-notes-2.1.0.md
new file mode 100644
index 0000000000000..b32864990b82e
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.1.0.md
@@ -0,0 +1,120 @@
+## 2022-07-07 Version 2.1.0 Release Notes
+
+### Features/Enhancements
+
+* Rename package 'o.o.action.support.master' to 'o.o.action.support.clustermanager' (#3556) ([#3597](https://github.com/opensearch-project/opensearch/pull/3597))
+* Support dynamic node role (#3436) ([#3585](https://github.com/opensearch-project/opensearch/pull/3585))
+* Support use of IRSA for repository-s3 plugin credentials (#3475) ([#3486](https://github.com/opensearch-project/opensearch/pull/3486))
+* Filter out invalid URI and HTTP method in the error message of no handler found for a REST request (#3459) ([#3485](https://github.com/opensearch-project/opensearch/pull/3485))
+* Set term vector flags to false for ._index_prefix field (#1901). (#3119) ([#3447](https://github.com/opensearch-project/opensearch/pull/3447))
+* Replace internal usages of 'master' term in 'server/src/test' directory (#2520) ([#3444](https://github.com/opensearch-project/opensearch/pull/3444))
+* Rename master to cluster_manager in the XContent Parser of ClusterHealthResponse (#3432) ([#3438](https://github.com/opensearch-project/opensearch/pull/3438))
+* Replace internal usages of 'master' term in 'server/src/internalClusterTest' directory (#2521) ([#3407](https://github.com/opensearch-project/opensearch/pull/3407))
+* Replace 'master' terminology with 'cluster manager' in 'qa' directory (#3330) ([#3332](https://github.com/opensearch-project/opensearch/pull/3332))
+* Replace 'master' terminology with 'cluster manager' in 'modules' directory (#3328) ([#3333](https://github.com/opensearch-project/opensearch/pull/3333))
+* Replace 'master' terminology with 'cluster manager' in 'plugins' directory (#3329) ([#3334](https://github.com/opensearch-project/opensearch/pull/3334))
+* Replace internal usages of 'master' term in 'test' directory (#3283) ([#3293](https://github.com/opensearch-project/opensearch/pull/3293))
+* Replace internal usages of 'master' term in 'client' directory (#3088) ([#3284](https://github.com/opensearch-project/opensearch/pull/3284))
+* Replace internal usages of 'master' term in 'test' directory (#3283) ([#3293](https://github.com/opensearch-project/opensearch/pull/3293))
+* Replace internal usages of 'master' term in 'client' directory (#3088) ([#3284](https://github.com/opensearch-project/opensearch/pull/3284))
+* Replace internal usages of 'master' term in 'server/src/main' directory (#2519) ([#3165](https://github.com/opensearch-project/opensearch/pull/3165))
+* Rename ClusterBlock description 'no master' to 'no cluster-manager' (#3133) ([#3151](https://github.com/opensearch-project/opensearch/pull/3151))
+* Correct the skip version, multi_terms aggregation is supported on 2.1 (#3072) ([#3073](https://github.com/opensearch-project/opensearch/pull/3073))
+* Adds the replication type index setting, alongside a formal notion of feature flags (#3037) ([#3071](https://github.com/opensearch-project/opensearch/pull/3071))
+* Add new multi_term aggregation (#2687) ([#3022](https://github.com/opensearch-project/opensearch/pull/3022))
+* Add `positive_score_impact` support for `rank_features` (#2725) ([#2968](https://github.com/opensearch-project/opensearch/pull/2968))
+* [Backport 2.x] Add resource stats to task framework ([#2655](https://github.com/opensearch-project/opensearch/pull/2655))
+* Optimize Node, remove duplicate Settings (#2703) ([#2742](https://github.com/opensearch-project/opensearch/pull/2742))
+* [Backport 2.x] Add request parameter 'cluster_manager_timeout' as the alternative for 'master_timeout', and deprecate 'master_timeout' - in CAT APIs ([#2716](https://github.com/opensearch-project/opensearch/pull/2716))
+* Enable merge on refresh and merge on commit on Opensearch (#2535) ([#2600](https://github.com/opensearch-project/opensearch/pull/2600))
+* Concurrent Searching (Experimental) (#1500) ([#2584](https://github.com/opensearch-project/opensearch/pull/2584))
+* [Type removal] Remove type from BulkRequestParser (#3423) ([#3431](https://github.com/opensearch-project/opensearch/pull/3431))
+* [Type removal] _type removal from tests of yaml tests (#3406) ([#3414](https://github.com/opensearch-project/opensearch/pull/3414))
+* [2.x] Deprecate public methods and variables with master term in package 'org.opensearch.action.support.master' (#3617) ([#3643](https://github.com/opensearch-project/opensearch/pull/3643))
+* Deprecate classes in org.opensearch.action.support.master (#3593) ([#3609](https://github.com/opensearch-project/opensearch/pull/3609))
+* [TEST] Add back necessary tests for deprecated settings that are replaced during applying inclusive naming (#2825) ([#3353](https://github.com/opensearch-project/opensearch/pull/3353))
+* Support use of IRSA for repository-s3 plugin credentials: added YAML Rest test case (#3499) ([#3520](https://github.com/opensearch-project/opensearch/pull/3520))
+* [Backport 2.x] Add type mapping removal bwc tests for indexing, searching, snapshots ([#2921](https://github.com/opensearch-project/opensearch/pull/2921))
+
+
+### Bug Fixes
+
+* [BUG] Custom POM configuration for ZIP publication produces duplicit tags (url, scm) (#3656) ([#3680](https://github.com/opensearch-project/opensearch/pull/3680))
+* [BUG] opensearch crashes on closed client connection before search reply (#3626) ([#3645](https://github.com/opensearch-project/opensearch/pull/3645))
+* Fix false positive query timeouts due to using cached time (#3454) ([#3624](https://github.com/opensearch-project/opensearch/pull/3624))
+* Fix NPE when minBound/maxBound is not set before being called. (#3605) ([#3610](https://github.com/opensearch-project/opensearch/pull/3610))
+* Fix for bug showing incorrect awareness attributes count in AwarenessAllocationDecider (#3428) ([#3580](https://github.com/opensearch-project/opensearch/pull/3580))
+* Add flat_skew setting to node overload decider (#3563) ([#3582](https://github.com/opensearch-project/opensearch/pull/3582))
+* Fix the support of RestClient Node Sniffer for version 2.x and update tests (#3487) ([#3521](https://github.com/opensearch-project/opensearch/pull/3521))
+* move bash flag to set statement (#3494) ([#3519](https://github.com/opensearch-project/opensearch/pull/3519))
+* [BUG] Fixing org.opensearch.monitor.os.OsProbeTests > testLogWarnCpuMessageOnlyOnes when cgroups are available but cgroup stats is not (#3448) ([#3464](https://github.com/opensearch-project/opensearch/pull/3464))
+* Removing unused method from TransportSearchAction (#3437) ([#3445](https://github.com/opensearch-project/opensearch/pull/3445))
+* Fix Lucene-snapshots repo for jdk 17. (#3396) ([#3404](https://github.com/opensearch-project/opensearch/pull/3404))
+* Temporary adding Apache Lucene repositories for snapshots (#3042) ([#3047](https://github.com/opensearch-project/opensearch/pull/3047))
+* Excluding system indices from max shard limit validator (#2894) ([#2911](https://github.com/opensearch-project/opensearch/pull/2911))
+* [Backport] [2.x] Bugfix to guard against stack overflow errors caused by very large reg-ex input  ([#2817](https://github.com/opensearch-project/opensearch/pull/2817))
+
+### Infrastructure
+
+* Move gradle-check code to its own scripts and upload codecov (#3742) ([#3747](https://github.com/opensearch-project/opensearch/pull/3747))
+* Optimize Gradle builds by enabling local build caching (#3718) ([#3737](https://github.com/opensearch-project/opensearch/pull/3737))
+* Update github action gradle-check to use pull_request_target for accessing token (#3728) ([#3731](https://github.com/opensearch-project/opensearch/pull/3731))
+* Add gradle check test for github workflows (#3717) ([#3723](https://github.com/opensearch-project/opensearch/pull/3723))
+* Used set to make shell scripts more strict (#3278) ([#3344](https://github.com/opensearch-project/opensearch/pull/3344))
+* Bootstrap should implement a denylist of Java versions (ranges) (#3164) ([#3292](https://github.com/opensearch-project/opensearch/pull/3292))
+* Add Github Workflow to build and publish lucene snapshots. (#2906) ([#3038](https://github.com/opensearch-project/opensearch/pull/3038))
+* Remove JavaVersion in favour of standard Runtime.Version (java-version-checker) (#3027) ([#3034](https://github.com/opensearch-project/opensearch/pull/3034))
+* Remove JavaVersion, use builtin Runtime.Version to deal with runtime versions (#3006) ([#3013](https://github.com/opensearch-project/opensearch/pull/3013))
+* [Backport 2.x] Added a new line linter ([#2892](https://github.com/opensearch-project/opensearch/pull/2892))
+
+### Maintenance
+
+* Added bwc version 2.0.2 ([#3612](https://github.com/opensearch-project/opensearch/pull/3612))
+* Added bwc version 1.3.4 (#3551) ([#3583](https://github.com/opensearch-project/opensearch/pull/3583))
+* Bump guava from 18.0 to 23.0 in /plugins/ingest-attachment (#3357) ([#3534](https://github.com/opensearch-project/opensearch/pull/3534))
+* Added bwc version 2.0.1 ([#3451](https://github.com/opensearch-project/opensearch/pull/3451))
+* Bump google-auth-library-oauth2-http from 0.20.0 to 1.7.0 in /plugins/repository-gcs (#3473) ([#3488](https://github.com/opensearch-project/opensearch/pull/3488))
+* Bump protobuf-java from 3.20.1 to 3.21.1 in /plugins/repository-hdfs (#3472) ([#3480](https://github.com/opensearch-project/opensearch/pull/3480))
+* Bump reactor-core from 3.4.17 to 3.4.18 in /plugins/repository-azure (#3427) ([#3430](https://github.com/opensearch-project/opensearch/pull/3430))
+* Bump com.gradle.enterprise from 3.10 to 3.10.1 (#3425) ([#3429](https://github.com/opensearch-project/opensearch/pull/3429))
+* Bump reactor-netty-core from 1.0.16 to 1.0.19 in /plugins/repository-azure (#3360) ([#3386](https://github.com/opensearch-project/opensearch/pull/3386))
+* Bump xz from 1.8 to 1.9 in /plugins/ingest-attachment (#3248) ([#3280](https://github.com/opensearch-project/opensearch/pull/3280))
+* Upgrading ingest-attachment dependencies (#3111) ([#3279](https://github.com/opensearch-project/opensearch/pull/3279))
+* Bump reactor-netty from 1.0.17 to 1.0.18 in /plugins/repository-azure (#3246) ([#3258](https://github.com/opensearch-project/opensearch/pull/3258))
+* Bump google-http-client-appengine from 1.35.0 to 1.41.8 in /plugins/repository-gcs (#3247) ([#3259](https://github.com/opensearch-project/opensearch/pull/3259))
+* Bump HdrHistogram from 2.1.9 to 2.1.12 in /server (#2135) ([#3200](https://github.com/opensearch-project/opensearch/pull/3200))
+* Add bwc version 1.3.3 ([#3221](https://github.com/opensearch-project/opensearch/pull/3221))
+* Bump commons-lang3 from 3.9 to 3.12.0 in /plugins/ingest-attachment (#3190) ([#3194](https://github.com/opensearch-project/opensearch/pull/3194))
+* Bump google-api-client from 1.30.10 to 1.34.0 in /plugins/repository-gcs (#3161) ([#3191](https://github.com/opensearch-project/opensearch/pull/3191))
+* Bump reactor-netty-http from 1.0.16 to 1.0.18 in /plugins/repository-azure (#3057) ([#3070](https://github.com/opensearch-project/opensearch/pull/3070))
+* Bump com.gradle.enterprise from 3.9 to 3.10 (#3055) ([#3069](https://github.com/opensearch-project/opensearch/pull/3069))
+* Bump protobuf-java from 3.20.0 to 3.20.1 in /plugins/repository-hdfs (#3062) ([#3068](https://github.com/opensearch-project/opensearch/pull/3068))
+* Bump protobuf-java from 3.20.0 to 3.20.1 in /plugins/repository-hdfs (#3062) ([#3068](https://github.com/opensearch-project/opensearch/pull/3068))
+* Bump json-schema-validator from 1.0.68 to 1.0.69 in /buildSrc (#3060) ([#3066](https://github.com/opensearch-project/opensearch/pull/3066))
+* Add Gradle 7.4 Aggregated Test Reports (#2821) ([#2983](https://github.com/opensearch-project/opensearch/pull/2983))
+* Bump google-oauth-client from 1.33.2 to 1.33.3 in /plugins/discovery-gce (#2943) ([#2966](https://github.com/opensearch-project/opensearch/pull/2966))
+* Bump org.gradle.test-retry from 1.3.1 to 1.3.2 (#2940) ([#2960](https://github.com/opensearch-project/opensearch/pull/2960))
+* Bump reactor-core from 3.4.15 to 3.4.17 in /plugins/repository-azure (#2947) ([#2961](https://github.com/opensearch-project/opensearch/pull/2961))
+* Bump grpc-context from 1.29.0 to 1.45.1 in /plugins/repository-gcs (#2944) ([#2962](https://github.com/opensearch-project/opensearch/pull/2962))
+* Bump guava from 30.1.1-jre to 31.1-jre in /plugins/repository-hdfs (#2948) ([#2959](https://github.com/opensearch-project/opensearch/pull/2959))
+* Bump reactor-netty from 1.0.16 to 1.0.17 in /plugins/repository-azure (#2613) ([#2958](https://github.com/opensearch-project/opensearch/pull/2958))
+* Bump hadoop-minicluster from 3.3.1 to 3.3.2 in /test/fixtures/hdfs-fixture (#2381) ([#2957](https://github.com/opensearch-project/opensearch/pull/2957))
+* Bump com.diffplug.spotless from 6.4.1 to 6.4.2 (#2827) ([#2956](https://github.com/opensearch-project/opensearch/pull/2956))
+* Bump jna from 5.10.0 to 5.11.0 in /buildSrc (#2946) ([#2955](https://github.com/opensearch-project/opensearch/pull/2955))
+* Adding asm to version file and upgrading (#2933) ([#2951](https://github.com/opensearch-project/opensearch/pull/2951))
+* [Backport 2.x] Update commons-logging to 1.2 ([#2823](https://github.com/opensearch-project/opensearch/pull/2823))
+* Bump gradle-info-plugin from 7.1.3 to 11.3.3 in /buildSrc (#2831) ([#2842](https://github.com/opensearch-project/opensearch/pull/2842))
+* Update azure-storage-blob to 12.15.0: fix test flakiness (#2795) ([#2798](https://github.com/opensearch-project/opensearch/pull/2798))
+* Bump proto-google-common-protos from 1.16.0 to 2.8.0 in /plugins/repository-gcs (#2738) ([#2743](https://github.com/opensearch-project/opensearch/pull/2743))
+* Update to Gradle 7.4.2 (#2688) ([#2692](https://github.com/opensearch-project/opensearch/pull/2692))
+* Update Gradle to 7.4.1 (#2078) ([#2645](https://github.com/opensearch-project/opensearch/pull/2645))
+* Lock 2.1 release to Lucene 9.2.0. ([#3676](https://github.com/opensearch-project/opensearch/pull/3676))
+* [Dependency upgrade] google-oauth-client to 1.33.3 (#3500) ([#3501](https://github.com/opensearch-project/opensearch/pull/3501))
+
+### Refactoring
+
+* [Refactor] XContentType to parse Accept or Content-Type headers (#3077) ([#3103](https://github.com/opensearch-project/opensearch/pull/3103))
+* Remove usages of MultiTermQuery.setRewriteMethodsetRewriteMethod (#2997) ([#3017](https://github.com/opensearch-project/opensearch/pull/3017))
+* Refactoring GatedAutoCloseable and moving RecoveryState.Timer (#2965) ([#3014](https://github.com/opensearch-project/opensearch/pull/3014))
+* Fixing flakiness of ShuffleForcedMergePolicyTests (#3591) ([#3592](https://github.com/opensearch-project/opensearch/pull/3592))
+* Fix testSetAdditionalRolesCanAddDeprecatedMasterRole() by removing the initial assertion (#3441) ([#3443](https://github.com/opensearch-project/opensearch/pull/3443))
diff --git a/release-notes/opensearch.release-notes-2.10.0.md b/release-notes/opensearch.release-notes-2.10.0.md
new file mode 100644
index 0000000000000..9d5f75d61ee2a
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.10.0.md
@@ -0,0 +1,136 @@
+## 2023-09-08 Version 2.10.0 Release Notes
+
+## [2.10]
+
+### Added
+- Add server version as REST response header [#6583](https://github.com/opensearch-project/OpenSearch/issues/6583)
+- Start replication checkpointTimers on primary before segments upload to remote store. ([#8221]()https://github.com/opensearch-project/OpenSearch/pull/8221)
+- Introduce new static cluster setting to control slice computation for concurrent segment search. ([#8847](https://github.com/opensearch-project/OpenSearch/pull/8884))
+- Add configuration for file cache size to max remote data ratio to prevent oversubscription of file cache ([#8606](https://github.com/opensearch-project/OpenSearch/pull/8606))
+- Disallow compression level to be set for default and best_compression index codecs ([#8737]()https://github.com/opensearch-project/OpenSearch/pull/8737)
+- [distribution/archives] [Linux] [x64] Provide the variant of the distributions bundled with JRE ([#8195]()https://github.com/opensearch-project/OpenSearch/pull/8195)
+- Prioritize replica shard movement during shard relocation ([#8875](https://github.com/opensearch-project/OpenSearch/pull/8875))
+- Introducing Default and Best Compression codecs as their algorithm name ([#9123](https://github.com/opensearch-project/OpenSearch/pull/9123))
+- Make SearchTemplateRequest implement IndicesRequest.Replaceable ([#9122](https://github.com/opensearch-project/OpenSearch/pull/9122))
+- [BWC and API enforcement] Define the initial set of annotations, their meaning and relations between them ([#9223](https://github.com/opensearch-project/OpenSearch/pull/9223))
+- [Remote Store] Add Segment download stats to remotestore stats API ([#8718](https://github.com/opensearch-project/OpenSearch/pull/8718))
+- [Remote Store] Add remote segment transfer stats on NodesStats API ([#9168](https://github.com/opensearch-project/OpenSearch/pull/9168) [#9393](https://github.com/opensearch-project/OpenSearch/pull/9393) [#9454](https://github.com/opensearch-project/OpenSearch/pull/9454))
+- [Segment Replication] Support realtime reads for GET requests ([#9212](https://github.com/opensearch-project/OpenSearch/pull/9212))
+- Allow test clusters to run with TLS ([#8900](https://github.com/opensearch-project/OpenSearch/pull/8900))
+- Add jdk.incubator.vector module support for JDK 20+ ([#8601](https://github.com/opensearch-project/OpenSearch/pull/8601))
+- [Feature] Expose term frequency in Painless script score context ([#9081](https://github.com/opensearch-project/OpenSearch/pull/9081))
+- Add support for reading partial files to HDFS repository ([#9513](https://github.com/opensearch-project/OpenSearch/issues/9513))
+- [Remote Store] Rate limiter integration for remote store uploads and downloads([#9448](https://github.com/opensearch-project/OpenSearch/pull/9448/))
+- [BWC and API enforcement] Decorate the existing APIs with proper annotations (part 1) ([#9520](https://github.com/opensearch-project/OpenSearch/pull/9520))
+- Add support for extensions to search responses using SearchExtBuilder ([#9379](https://github.com/opensearch-project/OpenSearch/pull/9379))
+- [Remote State] Create service to publish cluster state to remote store ([#9160](https://github.com/opensearch-project/OpenSearch/pull/9160))
+- Core crypto library to perform encryption and decryption of source content ([#8466](https://github.com/opensearch-project/OpenSearch/pull/8466))
+- Expose DelimitedTermFrequencyTokenFilter to allow providing term frequencies along with terms ([#9479](https://github.com/opensearch-project/OpenSearch/pull/9479))
+- APIs for performing async blob reads and async downloads from the repository using multiple streams ([#9592](https://github.com/opensearch-project/OpenSearch/issues/9592))
+- Add concurrent segment search related metrics to node and index stats ([#9622](https://github.com/opensearch-project/OpenSearch/issues/9622))
+- Add average concurrency metric for concurrent segment search ([#9670](https://github.com/opensearch-project/OpenSearch/issues/9670))
+- Introduce cluster default remote translog buffer interval setting ([#9584](https://github.com/opensearch-project/OpenSearch/pull/9584))
+- Added encryption-sdk lib to provide encryption and decryption capabilities ([#8466](https://github.com/opensearch-project/OpenSearch/pull/8466) [#9289](https://github.com/opensearch-project/OpenSearch/pull/9289))
+- [Segment Replication] Adding segment replication statistics rolled up at index, node and cluster level ([#9709](https://github.com/opensearch-project/OpenSearch/pull/9709))
+- Added crypto-kms plugin to provide AWS KMS based key providers for encryption/decryption. ([#8465](https://github.com/opensearch-project/OpenSearch/pull/8465))
+- [Remote state] Integrate remote cluster state in publish/commit flow ([#9665](https://github.com/opensearch-project/OpenSearch/pull/9665))
+- [Remote Store] Changes to introduce repository registration during bootstrap via node attributes. ([#9105](https://github.com/opensearch-project/OpenSearch/pull/9105))
+- [Remote state] Auto restore index metadata from last known cluster state ([#9831](https://github.com/opensearch-project/OpenSearch/pull/9831))
+
+### Dependencies
+- Bump `org.apache.logging.log4j:log4j-core` from 2.17.1 to 2.20.0 ([#8307](https://github.com/opensearch-project/OpenSearch/pull/8307))
+- Bump `io.grpc:grpc-context` from 1.46.0 to 1.57.1 ([#8726](https://github.com/opensearch-project/OpenSearch/pull/8726), [#9145](https://github.com/opensearch-project/OpenSearch/pull/9145))
+- Bump `com.netflix.nebula:gradle-info-plugin` from 12.1.5 to 12.1.6 ([#8724](https://github.com/opensearch-project/OpenSearch/pull/8724))
+- Bump `commons-codec:commons-codec` from 1.15 to 1.16.0 ([#8725](https://github.com/opensearch-project/OpenSearch/pull/8725))
+- Bump `org.apache.zookeeper:zookeeper` from 3.8.1 to 3.9.0 ([#8844](https://github.com/opensearch-project/OpenSearch/pull/8844), [#9146](https://github.com/opensearch-project/OpenSearch/pull/9146))
+- Bump `org.gradle.test-retry` from 1.5.3 to 1.5.4 ([#8842](https://github.com/opensearch-project/OpenSearch/pull/8842))
+- Bump `com.netflix.nebula.ospackage-base` from 11.3.0 to 11.4.0 ([#8838](https://github.com/opensearch-project/OpenSearch/pull/8838))
+- Bump `com.google.http-client:google-http-client-gson` from 1.43.2 to 1.43.3 ([#8840](https://github.com/opensearch-project/OpenSearch/pull/8840))
+- OpenJDK Update (July 2023 Patch releases) ([#8869](https://github.com/opensearch-project/OpenSearch/pull/8869))
+- Bump `hadoop` libraries from 3.3.4 to 3.3.6 ([#6995](https://github.com/opensearch-project/OpenSearch/pull/6995))
+- Bump `com.gradle.enterprise` from 3.13.3 to 3.14.1 ([#8996](https://github.com/opensearch-project/OpenSearch/pull/8996))
+- Bump `org.apache.commons:commons-lang3` from 3.12.0 to 3.13.0 ([#8995](https://github.com/opensearch-project/OpenSearch/pull/8995))
+- Bump `com.google.cloud:google-cloud-core-http` from 2.21.0 to 2.21.1 ([#8999](https://github.com/opensearch-project/OpenSearch/pull/8999))
+- Bump `com.maxmind.geoip2:geoip2` from 4.0.1 to 4.1.0 ([#8998](https://github.com/opensearch-project/OpenSearch/pull/8998))
+- Bump `org.apache.commons:commons-lang3` from 3.12.0 to 3.13.0 in /plugins/repository-hdfs ([#8997](https://github.com/opensearch-project/OpenSearch/pull/8997))
+- Bump `netty` from 4.1.94.Final to 4.1.96.Final ([#9030](https://github.com/opensearch-project/OpenSearch/pull/9030))
+- Bump `com.google.jimfs:jimfs` from 1.2 to 1.3.0 ([#9080](https://github.com/opensearch-project/OpenSearch/pull/9080))
+- Bump `io.projectreactor.netty:reactor-netty-http` from 1.1.8 to 1.1.9 ([#9147](https://github.com/opensearch-project/OpenSearch/pull/9147))
+- Bump `org.apache.maven:maven-model` from 3.9.3 to 3.9.4 ([#9148](https://github.com/opensearch-project/OpenSearch/pull/9148))
+- Bump `com.azure:azure-storage-blob` from 12.22.3 to 12.23.0 ([#9231](https://github.com/opensearch-project/OpenSearch/pull/9231))
+- Bump `com.diffplug.spotless` from 6.19.0 to 6.20.0 ([#9227](https://github.com/opensearch-project/OpenSearch/pull/9227))
+- Bump `org.xerial.snappy:snappy-java` from 1.1.8.2 to 1.1.10.3 ([#9252](https://github.com/opensearch-project/OpenSearch/pull/9252))
+- Bump `com.squareup.okhttp3:okhttp` from 4.9.3 to 4.11.0 ([#9252](https://github.com/opensearch-project/OpenSearch/pull/9252))
+- Bump `com.squareup.okio:okio` from 2.8.0 to 3.5.0 ([#9252](https://github.com/opensearch-project/OpenSearch/pull/9252))
+- Bump `com.google.code.gson:gson` from 2.9.0 to 2.10.1 ([#9230](https://github.com/opensearch-project/OpenSearch/pull/9230))
+- Bump `lycheeverse/lychee-action` from 1.2.0 to 1.8.0 ([#9228](https://github.com/opensearch-project/OpenSearch/pull/9228))
+- Bump `snakeyaml` from 2.0 to 2.1 ([#9269](https://github.com/opensearch-project/OpenSearch/pull/9269))
+- Bump `aws-actions/configure-aws-credentials` from 1 to 2 ([#9302](https://github.com/opensearch-project/OpenSearch/pull/9302))
+- Bump `com.github.luben:zstd-jni` from 1.5.5-3 to 1.5.5-5 ([#9431](https://github.com/opensearch-project/OpenSearch/pull/9431)
+- Bump `netty` from 4.1.96.Final to 4.1.97.Final ([#9553](https://github.com/opensearch-project/OpenSearch/pull/9553))
+- Bump `io.grpc:grpc-api` from 1.57.1 to 1.57.2 ([#9578](https://github.com/opensearch-project/OpenSearch/pull/9578))
+- Add Encryption SDK dependencies ([#8466](https://github.com/opensearch-project/OpenSearch/pull/8466))
+
+### Changed
+- Default to mmapfs within hybridfs ([#8508](https://github.com/opensearch-project/OpenSearch/pull/8508))
+- Perform aggregation postCollection in ContextIndexSearcher after searching leaves ([#8303](https://github.com/opensearch-project/OpenSearch/pull/8303))
+- Make Span exporter configurable ([#8620](https://github.com/opensearch-project/OpenSearch/issues/8620))
+- Perform aggregation postCollection in ContextIndexSearcher after searching leaves ([#8303](https://github.com/opensearch-project/OpenSearch/pull/8303))
+- [Refactor] StreamIO from common to core.common namespace in core lib ([#8157](https://github.com/opensearch-project/OpenSearch/pull/8157))
+- [Refactor] Remaining HPPC to java.util collections ([#8730](https://github.com/opensearch-project/OpenSearch/pull/8730))
+- Remote Segment Store Repository setting moved from `index.remote_store.repository` to `index.remote_store.segment.repository` and `cluster.remote_store.repository` to `cluster.remote_store.segment.repository` respectively for Index and Cluster level settings ([#8719](https://github.com/opensearch-project/OpenSearch/pull/8719))
+- Change InternalSignificantTerms to sum shard-level superset counts only in final reduce ([#8735](https://github.com/opensearch-project/OpenSearch/pull/8735))
+- Exclude 'benchmarks' from codecov report ([#8805](https://github.com/opensearch-project/OpenSearch/pull/8805))
+- Create separate SourceLookup instance per segment slice in SignificantTextAggregatorFactory ([#8807](https://github.com/opensearch-project/OpenSearch/pull/8807))
+- Replace the deprecated IndexReader APIs with new storedFields() & termVectors() ([#7792](https://github.com/opensearch-project/OpenSearch/pull/7792))
+- [Remote Store] Add support to restore only unassigned shards of an index ([#8792](https://github.com/opensearch-project/OpenSearch/pull/8792))
+- Add safeguard limits for file cache during node level allocation ([#8208](https://github.com/opensearch-project/OpenSearch/pull/8208))
+- Performance improvements for BytesRefHash ([#8788](https://github.com/opensearch-project/OpenSearch/pull/8788))
+- Add support for aggregation profiler with concurrent aggregation ([#8801](https://github.com/opensearch-project/OpenSearch/pull/8801))
+- [Remove] Deprecated Fractional ByteSizeValue support #9005 ([#9005](https://github.com/opensearch-project/OpenSearch/pull/9005))
+- Add support for aggregation profiler with concurrent aggregation ([#8801](https://github.com/opensearch-project/OpenSearch/pull/8801))
+- [Remote Store] Restrict user override for remote store index level settings ([#8812](https://github.com/opensearch-project/OpenSearch/pull/8812))
+- [Refactor] MediaTypeParser to MediaTypeParserRegistry ([#8636](https://github.com/opensearch-project/OpenSearch/pull/8636))
+- Make MultiBucketConsumerService thread safe to use across slices during search ([#9047](https://github.com/opensearch-project/OpenSearch/pull/9047))
+- Removed blocking wait in TransportGetSnapshotsAction which was exhausting generic threadpool ([#8377](https://github.com/opensearch-project/OpenSearch/pull/8377))
+- Adds support for tracing runnable scenarios ([#8831](https://github.com/opensearch-project/OpenSearch/pull/8831))
+- Change shard_size and shard_min_doc_count evaluation to happen in shard level reduce phase ([#9085](https://github.com/opensearch-project/OpenSearch/pull/9085))
+- Add attributes to startSpan methods ([#9199](https://github.com/opensearch-project/OpenSearch/pull/9199))
+- [Refactor] Task foundation classes to core library - pt 1 ([#9082](https://github.com/opensearch-project/OpenSearch/pull/9082))
+- Add support for wrapping CollectorManager with profiling during concurrent execution ([#9129](https://github.com/opensearch-project/OpenSearch/pull/9129))
+- Add base class for parameterizing the search based tests #9083 ([#9083](https://github.com/opensearch-project/OpenSearch/pull/9083))
+- Add support for wrapping CollectorManager with profiling during concurrent execution ([#9129](https://github.com/opensearch-project/OpenSearch/pull/9129))
+- Rethrow OpenSearch exception for non-concurrent path while using concurrent search ([#9177](https://github.com/opensearch-project/OpenSearch/pull/9177))
+- Improve performance of encoding composite keys in multi-term aggregations ([#9412](https://github.com/opensearch-project/OpenSearch/pull/9412))
+- Refactor Compressors from CompressorFactory to CompressorRegistry for extensibility ([#9262](https://github.com/opensearch-project/OpenSearch/pull/9262))
+- Fix sort related ITs for concurrent search ([#9177](https://github.com/opensearch-project/OpenSearch/pull/9466)
+- [Remote Store] Implicitly use replication type SEGMENT for remote store clusters ([#9264](https://github.com/opensearch-project/OpenSearch/pull/9264))
+- Add support to use trace propagated from client ([#9506](https://github.com/opensearch-project/OpenSearch/pull/9506))
+- Separate request-based and settings-based concurrent segment search controls and introduce AggregatorFactory method to determine concurrent search support ([#9469](https://github.com/opensearch-project/OpenSearch/pull/9469))
+- [Remote Store] Rate limiter integration for remote store uploads and downloads([#9448](https://github.com/opensearch-project/OpenSearch/pull/9448/))
+- [Remote Store] Implicitly use replication type SEGMENT for remote store clusters ([#9264](https://github.com/opensearch-project/OpenSearch/pull/9264))
+- Redefine telemetry context restoration and propagation ([#9617](https://github.com/opensearch-project/OpenSearch/pull/9617))
+- Use non-concurrent path for sort request on timeseries index and field([#9562](https://github.com/opensearch-project/OpenSearch/pull/9562))
+- Added sampler based on `Blanket Probabilistic Sampling rate` and `Override for on demand` ([#9621](https://github.com/opensearch-project/OpenSearch/issues/9621))
+- Decouple replication lag from logic to fail stale replicas ([#9507](https://github.com/opensearch-project/OpenSearch/pull/9507))
+- Improve performance of rounding dates in date_histogram aggregation ([#9727](https://github.com/opensearch-project/OpenSearch/pull/9727))
+- [Remote Store] Add support for Remote Translog Store stats in `_remotestore/stats/` API ([#9263](https://github.com/opensearch-project/OpenSearch/pull/9263))
+- Removing the vec file extension from INDEX_STORE_HYBRID_NIO_EXTENSIONS, to ensure the no performance degradation for vector search via Lucene Engine.([#9528](https://github.com/opensearch-project/OpenSearch/pull/9528)))
+- Cleanup Unreferenced file on segment merge failure ([#9503](https://github.com/opensearch-project/OpenSearch/pull/9503))
+- Move zstd compression codec to external custom-codecs repository ([#9422](https://github.com/opensearch-project/OpenSearch/issues/9422])
+- [Remote Store] Add support for Remote Translog Store upload stats in `_nodes/stats/` API ([#8908](https://github.com/opensearch-project/OpenSearch/pull/8908))
+- [Remote Store] Removing feature flag to mark feature GA ([#9761](https://github.com/opensearch-project/OpenSearch/pull/9761))
+
+### Removed
+- Remove provision to create Remote Indices without Remote Translog Store ([#8719](https://github.com/opensearch-project/OpenSearch/pull/8719))
+
+### Fixed
+- Fix flaky ResourceAwareTasksTests.testBasicTaskResourceTracking test ([#8993](https://github.com/opensearch-project/OpenSearch/pull/8993))
+- Fix null_pointer_exception when creating or updating ingest pipeline ([#9259](https://github.com/opensearch-project/OpenSearch/pull/9259))
+- Fix memory leak when using Zstd Dictionary ([#9403](https://github.com/opensearch-project/OpenSearch/pull/9403))
+- Fix condition to remove index create block ([#9437](https://github.com/opensearch-project/OpenSearch/pull/9437))
+- Add support to clear archived index setting ([#9019](https://github.com/opensearch-project/OpenSearch/pull/9019))
+- Fix range reads in respository-s3 ([9512](https://github.com/opensearch-project/OpenSearch/issues/9512))
+- [Segment Replication] Fixed bug where replica shard temporarily serves stale data during an engine reset ([#9495](https://github.com/opensearch-project/OpenSearch/pull/9495))
+- Disable shard/segment level search_after short cutting if track_total_hits != false ([#9683](https://github.com/opensearch-project/OpenSearch/pull/9683))
+- [Segment Replication] Fixed bug where bytes behind metric is not accurate ([#9686](https://github.com/opensearch-project/OpenSearch/pull/9686))
diff --git a/release-notes/opensearch.release-notes-2.2.0.md b/release-notes/opensearch.release-notes-2.2.0.md
new file mode 100644
index 0000000000000..74e76cfe46b5a
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.2.0.md
@@ -0,0 +1,79 @@
+## 2022-08-05 Version 2.2.0 Release Notes
+
+### Features/Enhancements
+
+* Task consumer Integration ([#2293](https://github.com/opensearch-project/opensearch/pull/2293)) ([#4141](https://github.com/opensearch-project/opensearch/pull/4141))
+* [Backport 2.x] [Segment Replication] Add SegmentReplicationTargetService to orchestrate replication events. ([#4074](https://github.com/opensearch-project/opensearch/pull/4074))
+* Support task resource tracking in OpenSearch ([#3982](https://github.com/opensearch-project/opensearch/pull/3982)) ([#4087](https://github.com/opensearch-project/opensearch/pull/4087))
+* Making shard copy count a multiple of attribute count ([#3462](https://github.com/opensearch-project/opensearch/pull/3462)) ([#4086](https://github.com/opensearch-project/opensearch/pull/4086))
+* [Backport 2.x] [Segment Rreplication] Adding CheckpointRefreshListener to trigger when Segment replication is turned on and Primary shard refreshes ([#4044](https://github.com/opensearch-project/opensearch/pull/4044))
+* Add doc_count field mapper ([#3985](https://github.com/opensearch-project/opensearch/pull/3985)) ([#4037](https://github.com/opensearch-project/opensearch/pull/4037))
+* Parallelize stale blobs deletion during snapshot delete ([#3796](https://github.com/opensearch-project/opensearch/pull/3796)) ([#3990](https://github.com/opensearch-project/opensearch/pull/3990))
+* [Backport 2.x] [Segment Replication] Add a new Engine implementation for replicas with segment replication enabled. ([#4003](https://github.com/opensearch-project/opensearch/pull/4003))
+* [Backport 2.x] Adds a new parameter, max_analyzer_offset, for the highlighter ([#4031](https://github.com/opensearch-project/opensearch/pull/4031))
+* Update merge on refresh and merge on commit defaults in Opensearch (Lucene 9.3) ([#3561](https://github.com/opensearch-project/opensearch/pull/3561)) ([#4013](https://github.com/opensearch-project/opensearch/pull/4013))
+* Make HybridDirectory MMAP Extensions Configurable ([#3837](https://github.com/opensearch-project/opensearch/pull/3837)) ([#3970](https://github.com/opensearch-project/opensearch/pull/3970))
+* Add option to disable chunked transfer-encoding ([#3864](https://github.com/opensearch-project/opensearch/pull/3864)) ([#3885](https://github.com/opensearch-project/opensearch/pull/3885))
+* Introducing TranslogManager implementations decoupled from the Engine [2.x] ([#3820](https://github.com/opensearch-project/opensearch/pull/3820))
+* Changing default  no_master_block from write to metadata_write ([#3621](https://github.com/opensearch-project/opensearch/pull/3621)) ([#3756](https://github.com/opensearch-project/opensearch/pull/3756))
+
+### Bug Fixes
+
+* OpenSearch crashes on closed client connection before search reply when total ops higher compared to expected ([#4143](https://github.com/opensearch-project/opensearch/pull/4143)) ([#4145](https://github.com/opensearch-project/opensearch/pull/4145))
+* Binding empty instance of SegmentReplicationCheckpointPublisher when Feature Flag is off in IndicesModule.java file. ([#4119](https://github.com/opensearch-project/opensearch/pull/4119))
+* Fix the bug that masterOperation(with task param) is bypassed ([#4103](https://github.com/opensearch-project/opensearch/pull/4103)) ([#4115](https://github.com/opensearch-project/opensearch/pull/4115))
+* Fixing flaky org.opensearch.cluster.routing.allocation.decider.DiskThresholdDeciderIT.testHighWatermarkNotExceeded test case ([#4012](https://github.com/opensearch-project/opensearch/pull/4012)) ([#4014](https://github.com/opensearch-project/opensearch/pull/4014))
+* Correct typo: Rutime -> Runtime ([#3896](https://github.com/opensearch-project/opensearch/pull/3896)) ([#3898](https://github.com/opensearch-project/opensearch/pull/3898))
+* Fixing implausibly old time stamp 1970-01-01 00:00:00 by using the timestamp from the Git revision instead of default 0 value ([#3883](https://github.com/opensearch-project/opensearch/pull/3883)) ([#3891](https://github.com/opensearch-project/opensearch/pull/3891))
+
+### Infrastructure
+
+* Correctly ignore depandabot branches during push ([#4077](https://github.com/opensearch-project/opensearch/pull/4077)) ([#4113](https://github.com/opensearch-project/opensearch/pull/4113))
+* Build performance improvements ([#3926](https://github.com/opensearch-project/opensearch/pull/3926)) ([#3937](https://github.com/opensearch-project/opensearch/pull/3937))
+* PR coverage requirement and default settings ([#3931](https://github.com/opensearch-project/opensearch/pull/3931)) ([#3938](https://github.com/opensearch-project/opensearch/pull/3938))
+* [Backport 2.x] Fail build on wildcard imports ([#3940](https://github.com/opensearch-project/opensearch/pull/3940))
+* Don't run EmptyDirTaskTests in a Docker container ([#3792](https://github.com/opensearch-project/opensearch/pull/3792)) ([#3912](https://github.com/opensearch-project/opensearch/pull/3912))
+* Add coverage, gha, jenkins server, documentation and forum badges ([#3886](https://github.com/opensearch-project/opensearch/pull/3886))
+* Unable to use Systemd module with tar distribution ([#3755](https://github.com/opensearch-project/opensearch/pull/3755)) ([#3903](https://github.com/opensearch-project/opensearch/pull/3903))
+* Ignore backport / autocut / dependentbot branches for gradle checks ([#3816](https://github.com/opensearch-project/opensearch/pull/3816)) ([#3825](https://github.com/opensearch-project/opensearch/pull/3825))
+* Setup branch push coverage and fix coverage uploads ([#3793](https://github.com/opensearch-project/opensearch/pull/3793)) ([#3811](https://github.com/opensearch-project/opensearch/pull/3811))
+* Enable XML test reports for Jenkins integration ([#3799](https://github.com/opensearch-project/opensearch/pull/3799)) ([#3803](https://github.com/opensearch-project/opensearch/pull/3803))
+
+### Maintenance
+
+* OpenJDK Update (July 2022 Patch releases) ([#4023](https://github.com/opensearch-project/opensearch/pull/4023)) ([#4092](https://github.com/opensearch-project/opensearch/pull/4092))
+* Update to Lucene 9.3.0 ([#4043](https://github.com/opensearch-project/opensearch/pull/4043)) ([#4088](https://github.com/opensearch-project/opensearch/pull/4088))
+* Bump commons-configuration2 from 2.7 to 2.8.0 in /plugins/repository-hdfs ([#3764](https://github.com/opensearch-project/opensearch/pull/3764)) ([#3783](https://github.com/opensearch-project/opensearch/pull/3783))
+* Use bash in systemd-entrypoint shebang ([#4008](https://github.com/opensearch-project/opensearch/pull/4008)) ([#4009](https://github.com/opensearch-project/opensearch/pull/4009))
+* Bump com.gradle.enterprise from 3.10.1 to 3.10.2 ([#3568](https://github.com/opensearch-project/opensearch/pull/3568)) ([#3934](https://github.com/opensearch-project/opensearch/pull/3934))
+* Bump log4j-core in /buildSrc/src/testKit/thirdPartyAudit/sample_jars ([#3763](https://github.com/opensearch-project/opensearch/pull/3763)) ([#3784](https://github.com/opensearch-project/opensearch/pull/3784))
+* Added bwc version 1.3.5 ([#3911](https://github.com/opensearch-project/opensearch/pull/3911)) ([#3913](https://github.com/opensearch-project/opensearch/pull/3913))
+* Update to Gradle 7.5 ([#3594](https://github.com/opensearch-project/opensearch/pull/3594)) ([#3904](https://github.com/opensearch-project/opensearch/pull/3904))
+* Update Netty to 4.1.79.Final ([#3868](https://github.com/opensearch-project/opensearch/pull/3868)) ([#3874](https://github.com/opensearch-project/opensearch/pull/3874))
+* Upgrade MinIO image version ([#3541](https://github.com/opensearch-project/opensearch/pull/3541)) ([#3867](https://github.com/opensearch-project/opensearch/pull/3867))
+* Add netty-transport-native-unix-common to modules/transport-netty4/bu… ([#3848](https://github.com/opensearch-project/opensearch/pull/3848)) ([#3853](https://github.com/opensearch-project/opensearch/pull/3853))
+* Update outdated dependencies ([#3821](https://github.com/opensearch-project/opensearch/pull/3821)) ([#3854](https://github.com/opensearch-project/opensearch/pull/3854))
+* Added bwc version 2.1.1 ([#3806](https://github.com/opensearch-project/opensearch/pull/3806))
+* Upgrade netty from 4.1.73.Final to 4.1.78.Final ([#3772](https://github.com/opensearch-project/opensearch/pull/3772)) ([#3778](https://github.com/opensearch-project/opensearch/pull/3778))
+* Bump protobuf-java from 3.21.1 to 3.21.2 in /plugins/repository-hdfs ([#3711](https://github.com/opensearch-project/opensearch/pull/3711)) ([#3726](https://github.com/opensearch-project/opensearch/pull/3726))
+* Upgrading AWS SDK dependency for native plugins ([#3694](https://github.com/opensearch-project/opensearch/pull/3694)) ([#3701](https://github.com/opensearch-project/opensearch/pull/3701))
+
+### Refactoring
+
+* [Backport 2.x] Changes to encapsulate Translog into TranslogManager ([#4095](https://github.com/opensearch-project/opensearch/pull/4095)) ([#4142](https://github.com/opensearch-project/opensearch/pull/4142))
+* Deprecate and rename abstract methods in interfaces that contain 'master' in name ([#4121](https://github.com/opensearch-project/opensearch/pull/4121)) ([#4123](https://github.com/opensearch-project/opensearch/pull/4123))
+* [Backport 2.x] Integrate Engine with decoupled Translog interfaces ([#3822](https://github.com/opensearch-project/opensearch/pull/3822))
+* Deprecate class FakeThreadPoolMasterService, BlockMasterServiceOnMaster and BusyMasterServiceDisruption ([#4058](https://github.com/opensearch-project/opensearch/pull/4058)) ([#4068](https://github.com/opensearch-project/opensearch/pull/4068))
+* Rename classes with name 'MasterService' to 'ClusterManagerService' in directory 'test/framework' ([#4051](https://github.com/opensearch-project/opensearch/pull/4051)) ([#4057](https://github.com/opensearch-project/opensearch/pull/4057))
+* Deprecate class 'MasterService' and create alternative class 'ClusterManagerService' ([#4022](https://github.com/opensearch-project/opensearch/pull/4022)) ([#4050](https://github.com/opensearch-project/opensearch/pull/4050))
+* Deprecate and Rename abstract methods from 'Master' terminology to 'ClusterManager'. ([#4032](https://github.com/opensearch-project/opensearch/pull/4032)) ([#4048](https://github.com/opensearch-project/opensearch/pull/4048))
+* Deprecate public methods and variables that contain 'master' terminology in class 'NoMasterBlockService' and 'MasterService' ([#4006](https://github.com/opensearch-project/opensearch/pull/4006)) ([#4038](https://github.com/opensearch-project/opensearch/pull/4038))
+* Deprecate public methods and variables that contain 'master' terminology in 'client' directory ([#3966](https://github.com/opensearch-project/opensearch/pull/3966)) ([#3981](https://github.com/opensearch-project/opensearch/pull/3981))
+* [segment replication]Introducing common Replication interfaces for segment replication and recovery code paths ([#3234](https://github.com/opensearch-project/opensearch/pull/3234)) ([#3984](https://github.com/opensearch-project/opensearch/pull/3984))
+* Deprecate public methods and variables that contain 'master' terminology in 'test/framework' directory  ([#3978](https://github.com/opensearch-project/opensearch/pull/3978)) ([#3987](https://github.com/opensearch-project/opensearch/pull/3987))
+* [Backport 2.x] [Segment Replication] Moving RecoveryState.Index to a top-level class and renaming ([#3971](https://github.com/opensearch-project/opensearch/pull/3971))
+* Rename and deprecate public methods that contains 'master' in the name in 'server' directory ([#3647](https://github.com/opensearch-project/opensearch/pull/3647)) ([#3964](https://github.com/opensearch-project/opensearch/pull/3964))
+* [2.x] Deprecate public class names with master terminology ([#3871](https://github.com/opensearch-project/opensearch/pull/3871)) ([#3914](https://github.com/opensearch-project/opensearch/pull/3914))
+* [Backport 2.x] Rename public classes with 'Master' to 'ClusterManager' ([#3870](https://github.com/opensearch-project/opensearch/pull/3870))
+* Revert renaming masterOperation() to clusterManagerOperation() ([#3681](https://github.com/opensearch-project/opensearch/pull/3681)) ([#3714](https://github.com/opensearch-project/opensearch/pull/3714))
+* Revert renaming method onMaster() and offMaster() in interface LocalNodeMasterListener ([#3686](https://github.com/opensearch-project/opensearch/pull/3686)) ([#3693](https://github.com/opensearch-project/opensearch/pull/3693))
diff --git a/release-notes/opensearch.release-notes-2.3.0.md b/release-notes/opensearch.release-notes-2.3.0.md
new file mode 100644
index 0000000000000..1532ab31106f7
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.3.0.md
@@ -0,0 +1,55 @@
+## 2022-09-08 Version 2.3.0 Release Notes
+
+### Features/Enhancements
+* [Backport to 2.x] [Segment Replication] - Update replicas to commit SegmentInfos instead of relying on segments_N from primary shards. ([#4450](https://github.com/opensearch-project/opensearch/pull/4450))
+* [Segment Replication] [Backport] Fix timeout issue by calculating time needed to process getSegmentFiles. ([#4434](https://github.com/opensearch-project/opensearch/pull/4434))
+* [Semgnet Replication] Update flaky testOnNewCheckpointFromNewPrimaryCancelOngoingReplication unit test ([#4414](https://github.com/opensearch-project/opensearch/pull/4414)) ([#4425](https://github.com/opensearch-project/opensearch/pull/4425))
+* [Segment Replication] Extend FileChunkWriter to allow cancel on transport client ([#4386](https://github.com/opensearch-project/opensearch/pull/4386)) ([#4424](https://github.com/opensearch-project/opensearch/pull/4424))
+* Segment Replication - Fix NoSuchFileException errors caused when computing metadata snapshot on primary shards. ([#4366](https://github.com/opensearch-project/opensearch/pull/4366)) ([#4422](https://github.com/opensearch-project/opensearch/pull/4422))
+* [Remote Store] Add index specific setting for remote repository ([#4253](https://github.com/opensearch-project/opensearch/pull/4253)) ([#4418](https://github.com/opensearch-project/opensearch/pull/4418))
+* [Segment Replication] Add check to cancel ongoing replication with old primary on onNewCheckpoint on replica ([#4363](https://github.com/opensearch-project/opensearch/pull/4363)) ([#4396](https://github.com/opensearch-project/opensearch/pull/4396))
+* [Segment Replication] Bump segment infos counter before commit during replica promotion ([#4365](https://github.com/opensearch-project/opensearch/pull/4365)) ([#4397](https://github.com/opensearch-project/opensearch/pull/4397))
+* Segment Replication - Implement segment replication event cancellation. ([#4225](https://github.com/opensearch-project/opensearch/pull/4225)) ([#4387](https://github.com/opensearch-project/opensearch/pull/4387))
+* [Backport 2.x] [Remote Store] Backport remote segment store changes ([#4380](https://github.com/opensearch-project/opensearch/pull/4380))
+* [Backport 2.x] Added timing data and more granular stages to SegmentReplicationState ([#4367](https://github.com/opensearch-project/opensearch/pull/4367))
+* [Backport 2.x] Support shard promotion with Segment Replication. ([#4135](https://github.com/opensearch-project/opensearch/pull/4135)) ([#4325](https://github.com/opensearch-project/opensearch/pull/4325))
+* [Segment Replication] Update PrimaryShardAllocator to prefer replicas with higher replication checkpoint ([#4041](https://github.com/opensearch-project/opensearch/pull/4041)) ([#4252](https://github.com/opensearch-project/opensearch/pull/4252))
+* [Backport 2.x] [Segment Replication] Backport all PR's containing remaining segment replication changes ([#4243](https://github.com/opensearch-project/opensearch/pull/4243))
+* [Backport 2.x] [Segment Replication]  Backport PR's : #3525  #3533  #3540 #3943 #3963 From main branch ([#4181](https://github.com/opensearch-project/opensearch/pull/4181))
+* [Backport 2.x] [Segment Replication] Added source-side classes for orchestrating replication events. ([#4128](https://github.com/opensearch-project/opensearch/pull/4128))
+
+### Bug Fixes
+*  [Bug]: gradle check failing with java heap OutOfMemoryError ([#4328](https://github.com/opensearch-project/opensearch/pull/4328)) ([#4442](https://github.com/opensearch-project/opensearch/pull/4442))
+* [Backport 2.x] Revert to Netty 4.1.79.Final ([#4432](https://github.com/opensearch-project/opensearch/pull/4432))
+* Bug fixes for dependabot changelog verifier ([#4364](https://github.com/opensearch-project/opensearch/pull/4364)) ([#4395](https://github.com/opensearch-project/opensearch/pull/4395))
+* [BUG] Create logs directory before running OpenSearch on Windows ([#4305](https://github.com/opensearch-project/opensearch/pull/4305)) ([#4335](https://github.com/opensearch-project/opensearch/pull/4335))
+* [BUG] Running "opensearch-service.bat start" and "opensearch-service.bat manager" ([#4289](https://github.com/opensearch-project/opensearch/pull/4289)) ([#4293](https://github.com/opensearch-project/opensearch/pull/4293))
+* [Backport 2.x] Do not fail replica shard due to primary closure ([#4309](https://github.com/opensearch-project/opensearch/pull/4309))
+* [Bug]: gradle check failing with java heap OutOfMemoryError ([#4150](https://github.com/opensearch-project/opensearch/pull/4150)) ([#4167](https://github.com/opensearch-project/opensearch/pull/4167))
+* OpenSearch crashes on closed client connection before search reply when total ops higher compared to expected ([#4143](https://github.com/opensearch-project/opensearch/pull/4143)) ([#4144](https://github.com/opensearch-project/opensearch/pull/4144))
+
+### Infrastructure
+* Add workflow for changelog verification ([#4085](https://github.com/opensearch-project/opensearch/pull/4085)) ([#4284](https://github.com/opensearch-project/opensearch/pull/4284))
+* Add 2.x version to CHANGELOG ([#4297](https://github.com/opensearch-project/opensearch/pull/4297)) ([#4303](https://github.com/opensearch-project/opensearch/pull/4303))
+* Update the head ref to changelog verifier ([#4296](https://github.com/opensearch-project/opensearch/pull/4296)) ([#4298](https://github.com/opensearch-project/opensearch/pull/4298))
+* Publish transport-netty4 module to central repository ([#4054](https://github.com/opensearch-project/opensearch/pull/4054)) ([#4078](https://github.com/opensearch-project/opensearch/pull/4078))
+
+### Maintenance
+* Add bwcVersion 1.3.6 to 2.x  ([#4452](https://github.com/opensearch-project/opensearch/pull/4452))
+* [AUTO] [2.x] Added bwc version 2.2.2. ([#4385](https://github.com/opensearch-project/opensearch/pull/4385))
+* Update to Netty 4.1.80.Final ([#4359](https://github.com/opensearch-project/opensearch/pull/4359)) ([#4374](https://github.com/opensearch-project/opensearch/pull/4374))
+* Adding @dreamer-89 to Opensearch maintainers. ([#4342](https://github.com/opensearch-project/opensearch/pull/4342)) ([#4345](https://github.com/opensearch-project/opensearch/pull/4345))
+* [CVE] Update snakeyaml dependency ([#4341](https://github.com/opensearch-project/opensearch/pull/4341)) ([#4347](https://github.com/opensearch-project/opensearch/pull/4347))
+* Some dependency updates ([#4308](https://github.com/opensearch-project/opensearch/pull/4308)) ([#4311](https://github.com/opensearch-project/opensearch/pull/4311))
+* Added bwc version 2.2.1 ([#4193](https://github.com/opensearch-project/opensearch/pull/4193))
+* Update Gradle to 7.5.1 ([#4211](https://github.com/opensearch-project/opensearch/pull/4211)) ([#4213](https://github.com/opensearch-project/opensearch/pull/4213))
+* [Backport] Upgrade dependencies ([#4165](https://github.com/opensearch-project/opensearch/pull/4165))
+* Bumping 2.x to 2.3.0 ([#4098](https://github.com/opensearch-project/opensearch/pull/4098))
+
+### Refactoring
+* Refactored the src and test of GeoHashGrid and GeoTileGrid Aggregations on GeoPoint from server folder to geo module.([#4071](https://github.com/opensearch-project/opensearch/pull/4071)) ([#4072](https://github.com/opensearch-project/opensearch/pull/4072)) ([#4180](https://github.com/opensearch-project/opensearch/pull/4180)) ([#4281](https://github.com/opensearch-project/opensearch/pull/4281))
+* Update the head ref to changelog verifier ([#4296](https://github.com/opensearch-project/opensearch/pull/4296)) ([#4298](https://github.com/opensearch-project/opensearch/pull/4298))
+* [2.x] Restore using the class ClusterInfoRequest and ClusterInfoRequestBuilder from package 'org.opensearch.action.support.master.info' for subclasses ([#4307](https://github.com/opensearch-project/opensearch/pull/4307)) ([#4324](https://github.com/opensearch-project/opensearch/pull/4324))
+* Refactored the src and test of GeoHashGrid and GeoTileGrid Aggregations on GeoPoint from server folder to geo module.([#4071](https://github.com/opensearch-project/opensearch/pull/4071)) ([#4072](https://github.com/opensearch-project/opensearch/pull/4072)) ([#4180](https://github.com/opensearch-project/opensearch/pull/4180)) ([#4281](https://github.com/opensearch-project/opensearch/pull/4281))
+* Refactors the GeoBoundsAggregation for geo_point types from the core server to the geo module. ([#4179](https://github.com/opensearch-project/opensearch/pull/4179))
+* Backporting multiple 2.* release notes from main to the 2.x branch ([#4154](https://github.com/opensearch-project/opensearch/pull/4154))
diff --git a/release-notes/opensearch.release-notes-2.4.0.md b/release-notes/opensearch.release-notes-2.4.0.md
new file mode 100644
index 0000000000000..2a377aa8fce0b
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.4.0.md
@@ -0,0 +1,101 @@
+## 2022-11-04 Version 2.4.0 Release Notes
+
+## [2.4]
+### Added
+- Introduce point in time search feature ([#3959](https://github.com/opensearch-project/OpenSearch/issues/3959))
+- Introduce experimental searchable snapshot feature ([#2919](https://github.com/opensearch-project/OpenSearch/issues/2919))
+- Add API for decommissioning/recommissioning zone and weighted zonal search request routing policy ([#3639](https://github.com/opensearch-project/OpenSearch/issues/3639))
+- Introduce cluster manager task throttling framework [#479](https://github.com/opensearch-project/OpenSearch/issues/479)
+- Add support for s390x architecture ([#4001](https://github.com/opensearch-project/OpenSearch/pull/4001))
+- Github workflow for changelog verification ([#4085](https://github.com/opensearch-project/OpenSearch/pull/4085))
+- Add failover support with Segment Replication enabled. ([#4325](https://github.com/opensearch-project/OpenSearch/pull/4325)
+- Add a new node role 'search' which is dedicated to provide search capability ([#4689](https://github.com/opensearch-project/OpenSearch/pull/4689))
+- Introduce Remote translog feature flag([#4158](https://github.com/opensearch-project/OpenSearch/pull/4158))
+- Add groupId value propagation tests for ZIP publication task ([#4848](https://github.com/opensearch-project/OpenSearch/pull/4848))
+- Add support for GeoJson Point type in GeoPoint field ([#4597](https://github.com/opensearch-project/OpenSearch/pull/4597))
+- Add missing no-jdk distributions ([#4722](https://github.com/opensearch-project/OpenSearch/pull/4722))
+- Copy `build.sh` over from opensearch-build ([#4887](https://github.com/opensearch-project/OpenSearch/pull/4887))
+- Update GeoGrid base class access modifier to support extensibility ([#4921](https://github.com/opensearch-project/OpenSearch/pull/4921))
+- Build no-jdk distributions as part of release build ([#4902](https://github.com/opensearch-project/OpenSearch/pull/4902))
+- Add in-flight cancellation of SearchShardTask based on resource consumption ([#4565](https://github.com/opensearch-project/OpenSearch/pull/4565))
+- Add resource usage trackers for in-flight cancellation of SearchShardTask ([#4805](https://github.com/opensearch-project/OpenSearch/pull/4805))
+- Add search backpressure stats API ([#4932](https://github.com/opensearch-project/OpenSearch/pull/4932))
+- Add feature to ignore indexes starting with dot during shard limit validation.([#4695](https://github.com/opensearch-project/OpenSearch/pull/4695))
+
+### Dependencies
+- Bump `com.diffplug.spotless` from 6.9.1 to 6.10.0
+- Bump `xmlbeans` from 5.1.0 to 5.1.1
+- Bump `hadoop-hdfs` from 3.3.3 to 3.3.4
+- Exclude jettison version brought in with hadoop-minicluster. ([#4787](https://github.com/opensearch-project/OpenSearch/pull/4787))
+- Bump protobuf-java to 3.21.7 in repository-gcs and repository-hdfs ([#4790](https://github.com/opensearch-project/OpenSearch/pull/4790))
+- Bump reactor-netty-http to 1.0.24 in repository-azure ([#4880](https://github.com/opensearch-project/OpenSearch/pull/4880))
+- Add dev help in gradle check CI failures ([4872](https://github.com/opensearch-project/OpenSearch/pull/4872))
+- Upgrade netty to 4.1.84.Final ([#4893](https://github.com/opensearch-project/OpenSearch/pull/4893))
+- Dependency updates: asm 9.3 -> 9.4, bytebuddy 1.12.12 -> 1.12.18 ([#4889](https://github.com/opensearch-project/OpenSearch/pull/4889))
+- Bump `tika` from 2.4.0 to 2.5.0 ([#4791](https://github.com/opensearch-project/OpenSearch/pull/4791))
+- Update Apache Lucene to 9.4.1 ([#4922](https://github.com/opensearch-project/OpenSearch/pull/4922))
+- Bump `woodstox-core` to 6.4.0 ([#4951](https://github.com/opensearch-project/OpenSearch/pull/4951))
+- Upgrade jetty-http, kotlin-stdlib and snakeyaml ([#4982](https://github.com/opensearch-project/OpenSearch/pull/4982))
+- OpenJDK Update (October 2022 Patch releases) ([#4997](https://github.com/opensearch-project/OpenSearch/pull/4997))
+- Upgrade zookeeper dependency in hdfs-fixture ([#5007](https://github.com/opensearch-project/OpenSearch/pull/5007))
+- Dependency updates (httpcore, mockito, slf4j, httpasyncclient, commons-codec) ([#4308](https://github.com/opensearch-project/OpenSearch/pull/4308))
+- Update to Apache Lucene 9.4.0 ([#4661](https://github.com/opensearch-project/OpenSearch/pull/4661))
+- Updated jackson to 2.13.4 and snakeyml to 1.32 ([#4556](https://github.com/opensearch-project/OpenSearch/pull/4556))
+- Update Jackson Databind to 2.13.4.2 (addressing CVE-2022-42003) ([#4781](https://github.com/opensearch-project/OpenSearch/pull/4781))
+- Bump protobuf-java to 3.21.8 ([#5005](https://github.com/opensearch-project/OpenSearch/pull/5005))
+- Upgrade zookeeper dependency in hdfs-fixture ([#5047](https://github.com/opensearch-project/OpenSearch/pull/5047))
+
+### Changed
+- Use RemoteSegmentStoreDirectory instead of RemoteDirectory ([#4240](https://github.com/opensearch-project/OpenSearch/pull/4240))
+- Weighted round-robin scheduling policy for shard coordination traffic ([#4241](https://github.com/opensearch-project/OpenSearch/pull/4241))
+- Add index specific setting for remote repository ([#4253](https://github.com/opensearch-project/OpenSearch/pull/4253))
+- Update replicas to commit SegmentInfos instead of relying on SIS files from primary shards. ([#4402](https://github.com/opensearch-project/OpenSearch/pull/4402))
+- Change the version to remove deprecated code of adding node name into log pattern of log4j property file ([#4569](https://github.com/opensearch-project/OpenSearch/pull/4569))
+- Load the deprecated master role in a dedicated method instead of in setAdditionalRoles() ([#4582](https://github.com/opensearch-project/OpenSearch/pull/4582))
+- Plugin ZIP publication groupId value is configurable ([#4156](https://github.com/opensearch-project/OpenSearch/pull/4156))
+- Further simplification of the ZIP publication implementation ([#4360](https://github.com/opensearch-project/OpenSearch/pull/4360))
+- Change behaviour in replica recovery for remote translog enabled indices ([#4318](https://github.com/opensearch-project/OpenSearch/pull/4318))
+- PUT api for weighted shard routing ([#4272](https://github.com/opensearch-project/OpenSearch/pull/4272))
+- GET api for weighted shard routing([#4275](https://github.com/opensearch-project/OpenSearch/pull/4275/))
+- Delete api for weighted shard routing([#4400](https://github.com/opensearch-project/OpenSearch/pull/4400/))
+- Fix weighted routing metadata deserialization error on process restart ([#4691](https://github.com/opensearch-project/OpenSearch/pull/4691))
+- Install and configure Log4j JUL Adapter for Lucene 9.4 ([#4754](https://github.com/opensearch-project/OpenSearch/pull/4754))
+- Use getParameterCount instead of getParameterTypes ([#4821](https://github.com/opensearch-project/OpenSearch/pull/4821))
+
+### Removed
+- Remove RepositoryData.MIN_VERSION support for next major release ([4729](https://github.com/opensearch-project/OpenSearch/pull/4729))
+
+### Fixed
+- `opensearch-service.bat start` and `opensearch-service.bat manager` failing to run ([#4289](https://github.com/opensearch-project/OpenSearch/pull/4289))
+- PR reference to checkout code for changelog verifier ([#4296](https://github.com/opensearch-project/OpenSearch/pull/4296))
+- `opensearch.bat` and `opensearch-service.bat install` failing to run, missing logs directory ([#4305](https://github.com/opensearch-project/OpenSearch/pull/4305))
+- Restore using the class ClusterInfoRequest and ClusterInfoRequestBuilder from package 'org.opensearch.action.support.master.info' for subclasses ([#4307](https://github.com/opensearch-project/OpenSearch/pull/4307))
+- Do not fail replica shard due to primary closure ([#4133](https://github.com/opensearch-project/OpenSearch/pull/4133))
+- Fixed cancellation of segment replication events ([#4225](https://github.com/opensearch-project/OpenSearch/pull/4225))
+- `opensearch.bat` fails to execute when install path includes spaces ([#4362](https://github.com/opensearch-project/OpenSearch/pull/4362))
+- Getting security exception due to access denied 'java.lang.RuntimePermission' 'accessDeclaredMembers' when trying to get snapshot with S3 IRSA ([#4469](https://github.com/opensearch-project/OpenSearch/pull/4469))
+- Fix the ignore_malformed setting to also ignore objects ([#4494](https://github.com/opensearch-project/OpenSearch/pull/4494))
+- Fix day of year defaulting for round up parser ([#4627](https://github.com/opensearch-project/OpenSearch/pull/4627))
+- Fix the SnapshotsInProgress error during index deletion ([#4570](https://github.com/opensearch-project/OpenSearch/pull/4570))
+- Fix invalid location of JDK dependency for arm64 architecture([#4613](https://github.com/opensearch-project/OpenSearch/pull/4613))
+- Alias filter lost after rollover ([#4499](https://github.com/opensearch-project/OpenSearch/pull/4499))
+- Fix Gradle warnings associated with publishPluginZipPublicationToXxx tasks ([#4696](https://github.com/opensearch-project/OpenSearch/pull/4696))
+- Fix a bug on handling an invalid array value for point type field #4900([#4900](https://github.com/opensearch-project/OpenSearch/pull/4900))
+- Set analyzer to regex query string search ([4219](https://github.com/opensearch-project/OpenSearch/pull/4219))
+- Better plural stemmer than minimal_english ([#4738](https://github.com/opensearch-project/OpenSearch/pull/4738))
+- Add check to cancel ongoing replication with old primary on onNewCheckpoint on replica ([#4363](https://github.com/opensearch-project/OpenSearch/pull/4363))
+- Bump segment infos counter before commit during replica promotion ([#4365](https://github.com/opensearch-project/OpenSearch/pull/4365))
+- Update flaky testOnNewCheckpointFromNewPrimaryCancelOngoingReplication unit test ([#4414](https://github.com/opensearch-project/OpenSearch/pull/4414))
+- Extend FileChunkWriter to allow cancel on transport client ([#4386](https://github.com/opensearch-project/OpenSearch/pull/4386))
+- Fix NoSuchFileExceptions with segment replication when computing primary metadata snapshots ([#4366](https://github.com/opensearch-project/OpenSearch/pull/4366))
+- Fix timeout issue by calculating time needed to process getSegmentFiles ([#4434](https://github.com/opensearch-project/OpenSearch/pull/4434))
+- Update replicas to commit SegmentInfos instead of relying on segments_N from primary shards ([#4450](https://github.com/opensearch-project/OpenSearch/pull/4450))
+- Adding check to make sure checkpoint is not processed when a shard's shard routing is primary ([#4716](https://github.com/opensearch-project/OpenSearch/pull/4716))
+- Fix bug of replica shard's translog not purging on index flush when segment replication is enabled ([4975](https://github.com/opensearch-project/OpenSearch/pull/4975))
+- Fix message "No OpenSearchException found" when detailed_error disabled by return meaningful messages ([#4708](https://github.com/opensearch-project/OpenSearch/pull/4708))
+- Add fix for auto expand replica validation ([#4994](https://github.com/opensearch-project/OpenSearch/pull/4994))
+- Fix build failures on the Windows platform ([#4924](https://github.com/opensearch-project/OpenSearch/issues/4924))
+- Fix error handling while reading analyzer mapping rules ([6d20423](https://github.com/opensearch-project/OpenSearch/commit/6d20423f5920745463b1abc5f1daf6a786c41aa0))
+
+### Security
+- CVE-2022-25857 org.yaml:snakeyaml DOS vulnerability ([#4341](https://github.com/opensearch-project/OpenSearch/pull/4341))
diff --git a/release-notes/opensearch.release-notes-2.4.1.md b/release-notes/opensearch.release-notes-2.4.1.md
new file mode 100644
index 0000000000000..a2e885f1f1282
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.4.1.md
@@ -0,0 +1,23 @@
+## 2022-12-13 Version 2.4.1 Release Notes
+
+### Bug Fixes
+* Fix 1.x compatibility bug with stored Tasks ([#5412](https://github.com/opensearch-project/opensearch/pull/5412)) ([#5440](https://github.com/opensearch-project/opensearch/pull/5440))
+* Use BuildParams.isCi() instead of checking env var ([#5368](https://github.com/opensearch-project/opensearch/pull/5368)) ([#5373](https://github.com/opensearch-project/opensearch/pull/5373))
+* [BUG] org.opensearch.repositories.s3.RepositoryS3ClientYamlTestSuiteIT/test {yaml=repository_s3/20_repository_permanent_credentials/Snapshot and Restore with repository-s3 using permanent credentials} flaky ([#5325](https://github.com/opensearch-project/opensearch/pull/5325)) ([#5336](https://github.com/opensearch-project/opensearch/pull/5336))
+* [BUG] Gradle Check Failed on Windows due to JDK19 pulling by gradle ([#5188](https://github.com/opensearch-project/opensearch/pull/5188)) ([#5192](https://github.com/opensearch-project/opensearch/pull/5192))
+* Fix test to use a file from another temp directory ([#5158](https://github.com/opensearch-project/opensearch/pull/5158)) ([#5163](https://github.com/opensearch-project/opensearch/pull/5163))
+* Fix boundary condition in indexing pressure test ([#5168](https://github.com/opensearch-project/opensearch/pull/5168)) ([#5182](https://github.com/opensearch-project/opensearch/pull/5182))
+* [Backport 2.x] Fix: org.opensearch.clustermanager.ClusterManagerTaskThrottlingIT is flaky. ([#5153](https://github.com/opensearch-project/opensearch/pull/5153)) ([#5171](https://github.com/opensearch-project/opensearch/pull/5171))
+* [Backport 2.4] Raise error on malformed CSV ([#5141](https://github.com/opensearch-project/opensearch/pull/5141))
+
+### Features/Enhancements
+* Change the output error message back to use OpenSearchException in the cause chain ([#5081](https://github.com/opensearch-project/opensearch/pull/5081)) ([#5085](https://github.com/opensearch-project/opensearch/pull/5085))
+* Revert changes in AbstractPointGeometryFieldMapper ([#5250](https://github.com/opensearch-project/opensearch/pull/5250))
+* Add support for skipping changelog ([#5088](https://github.com/opensearch-project/opensearch/pull/5088)) ([#5160](https://github.com/opensearch-project/opensearch/pull/5160))
+* [Backport 2.4]Revert "Cluster manager task throttling feature [Final PR] ([#5071](https://github.com/opensearch-project/opensearch/pull/5071))  ([#5203](https://github.com/opensearch-project/opensearch/pull/5203))
+
+### Maintenance
+* Update Apache Lucene to 9.4.2 ([#5354](https://github.com/opensearch-project/opensearch/pull/5354)) ([#5361](https://github.com/opensearch-project/opensearch/pull/5361))
+* Update Jackson to 2.14.1 ([#5346](https://github.com/opensearch-project/opensearch/pull/5346)) ([#5358](https://github.com/opensearch-project/opensearch/pull/5358))
+* Bump nebula-publishing-plugin from v4.4.0 to v4.6.0. ([#5127](https://github.com/opensearch-project/opensearch/pull/5127)) ([#5131](https://github.com/opensearch-project/opensearch/pull/5131))
+* Bump commons-compress from 1.21 to 1.22. ([#5520](https://github.com/opensearch-project/OpenSearch/pull/5520)) ([#5522](https://github.com/opensearch-project/opensearch/pull/5522))
diff --git a/release-notes/opensearch.release-notes-2.5.0.md b/release-notes/opensearch.release-notes-2.5.0.md
new file mode 100644
index 0000000000000..5bc08a3bf07e6
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.5.0.md
@@ -0,0 +1,57 @@
+## 2023-01-10 Version 2.5.0 Release Notes
+
+## [2.5]
+### Added
+- Prevent deletion of snapshots that are backing searchable snapshot indexes ([#5365](https://github.com/opensearch-project/OpenSearch/pull/5365))
+- Reject bulk requests with invalid actions ([#5384](https://github.com/opensearch-project/OpenSearch/issues/5384))
+- Add max_shard_size parameter for shrink API ([#5229](https://github.com/opensearch-project/OpenSearch/pull/5229))
+- Add experimental support for extensions ([#5347](https://github.com/opensearch-project/OpenSearch/pull/5347)), ([#5518](https://github.com/opensearch-project/OpenSearch/pull/5518)), ([#5597](https://github.com/opensearch-project/OpenSearch/pull/5597)), ([#5615](https://github.com/opensearch-project/OpenSearch/pull/5615)))
+- Add support to register settings dynamically ([#5495](https://github.com/opensearch-project/OpenSearch/pull/5495))
+- Add auto release workflow ([#5582](https://github.com/opensearch-project/OpenSearch/pull/5582))
+- Add CI bundle pattern to distribution download ([#5348](https://github.com/opensearch-project/OpenSearch/pull/5348))
+- Experimental support for extended backward compatiblity in searchable snapshots ([#5429](https://github.com/opensearch-project/OpenSearch/pull/5429))
+- Add support of default replica count cluster setting ([#5610](https://github.com/opensearch-project/OpenSearch/pull/5610))
+- Add support for refresh level durability ([#5253](https://github.com/opensearch-project/OpenSearch/pull/5253))
+- Add Request level Durability using Remote Translog functionality ([#5757](https://github.com/opensearch-project/OpenSearch/pull/5757))
+- Support to fail open requests on search shard failures with weighted traffic routing ([#5072](https://github.com/opensearch-project/OpenSearch/pull/5072))
+- Support versioning for Weighted routing apis([#5255](https://github.com/opensearch-project/OpenSearch/pull/5255))
+- Add support for discovered cluster manager and remove local weights ([#5680](https://github.com/opensearch-project/OpenSearch/pull/5680))
+- Add new level to get health per awareness attribute in _cluster/health ([#5694](https://github.com/opensearch-project/OpenSearch/pull/5694))
+
+### Changed
+- Change http code for DecommissioningFailedException from 500 to 400 ([#5283](https://github.com/opensearch-project/OpenSearch/pull/5283))
+- Pre conditions check before updating weighted routing metadata ([#4955](https://github.com/opensearch-project/OpenSearch/pull/4955))
+- Support remote translog transfer for request level durability ([#4480](https://github.com/opensearch-project/OpenSearch/pull/4480))
+- Gracefully handle concurrent zone decommission action ([#5542](https://github.com/opensearch-project/OpenSearch/pull/5542))
+
+### Deprecated
+- Refactor fuzziness interface on query builders ([#5433](https://github.com/opensearch-project/OpenSearch/pull/5433))
+
+### Fixed
+- Fix case sensitivity for wildcard queries ([#5462](https://github.com/opensearch-project/OpenSearch/pull/5462))
+- Apply cluster manager throttling settings during bootstrap ([#5524](https://github.com/opensearch-project/OpenSearch/pull/5524))
+- Update thresholds map when cluster manager throttling setting is removed ([#5524](https://github.com/opensearch-project/OpenSearch/pull/5524))
+- Fix backward compatibility for static cluster manager throttling threshold setting ([#5633](https://github.com/opensearch-project/OpenSearch/pull/5633))
+- Fix index exclusion behavior in snapshot restore and clone APIs ([#5626](https://github.com/opensearch-project/OpenSearch/pull/5626))
+- Fix graph filter error in search ([#5665](https://github.com/opensearch-project/OpenSearch/pull/5665))
+
+### Dependencies
+- Bumps `bcpg-fips` from 1.0.5.1 to 1.0.7.1 ([#5148](https://github.com/opensearch-project/OpenSearch/pull/5148))
+- Bumps `commons-compress` from 1.21 to 1.22 ([#5104](https://github.com/opensearch-project/OpenSearch/pull/5104))
+- Bumps `geoip2` from 3.0.1 to 3.0.2 in /modules/ingest-geoip ([#5201](https://github.com/opensearch-project/OpenSearch/pull/5201))
+- Bumps `gson` from 2.9.0 to 2.10 in /plugins/repository-hdfs ([#5184](https://github.com/opensearch-project/OpenSearch/pull/5184))
+- Bumps `protobuf-java` from 3.21.8 to 3.21.9 in /test/fixtures/hdfs-fixture ([#5185](https://github.com/opensearch-project/OpenSearch/pull/5185))
+- Bumps `gradle-extra-configurations-plugin` from 7.0.0 to 8.0.0 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `jcodings` from 1.0.57 to 1.0.58 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `google-http-client-jackson2` from 1.35.0 to 1.42.3 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `azure-core` from 1.33.0 to 1.34.0 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `azure-core-http-netty` from 1.12.4 to 1.12.7 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `maxmind-db` from 2.0.0 to 2.1.0 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `json-schema-validator` from 1.0.69 to 1.0.73 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `proto-google-common-protos` from 2.8.0 to 2.10.0 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `protobuf-java` from 3.21.7 to 3.21.9 ([#5330](https://github.com/opensearch-project/OpenSearch/pull/5330))
+- Bumps `gradle` from 7.5 to 7.6 ([#5382](https://github.com/opensearch-project/OpenSearch/pull/5382))
+- Bumps `jackson` from 2.14.0 to 2.14.1 ([#5355](https://github.com/opensearch-project/OpenSearch/pull/5355))
+- Bumps `apache-rat` from 0.13 to 0.15 ([#5686](https://github.com/opensearch-project/OpenSearch/pull/5686))
+- Bumps `reactor-netty` from 1.0.18 to 1.1.1 ([#5685](https://github.com/opensearch-project/OpenSearch/pull/5685))
+- Bumps `gradle-info-plugin` from 7.1.3 to 12.0.0 ([#5684](https://github.com/opensearch-project/OpenSearch/pull/5684))
diff --git a/release-notes/opensearch.release-notes-2.6.0.md b/release-notes/opensearch.release-notes-2.6.0.md
new file mode 100644
index 0000000000000..860e789be06ac
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.6.0.md
@@ -0,0 +1,57 @@
+## 2023-02-22 Version 2.6.0 Release Notes
+
+## [2.6]
+### Added
+- Add index create block when all nodes have breached high disk watermark ([#5852](https://github.com/opensearch-project/OpenSearch/pull/5852))
+- Add cluster manager throttling stats in nodes/stats API ([#5790](https://github.com/opensearch-project/OpenSearch/pull/5790))
+- Add support for feature flags in opensearch.yml ([#4959](https://github.com/opensearch-project/OpenSearch/pull/4959))
+- Add query for initialized extensions ([#5658](https://github.com/opensearch-project/OpenSearch/pull/5658))
+- Add update-index-settings allowlist for searchable snapshot ([#5907](https://github.com/opensearch-project/OpenSearch/pull/5907))
+- Add new cat/segment_replication API to surface Segment Replication metrics ([#5718](https://github.com/opensearch-project/OpenSearch/pull/5718)).
+- Replace latches with CompletableFutures for extensions ([#5646](https://github.com/opensearch-project/OpenSearch/pull/5646))
+- Add support to disallow search request with preference parameter with strict weighted shard routing([#5874](https://github.com/opensearch-project/OpenSearch/pull/5874))
+- Add support to apply index create block ([#4603](https://github.com/opensearch-project/OpenSearch/issues/4603))
+- Add support for minimum compatible version for extensions ([#6003](https://github.com/opensearch-project/OpenSearch/pull/6003))
+- Add a guardrail to limit maximum number of shard on the cluster ([#6143](https://github.com/opensearch-project/OpenSearch/pull/6143))
+- Add cancellation of in-flight SearchTasks based on resource consumption ([#5606](https://github.com/opensearch-project/OpenSearch/pull/5605))
+- Add support for ppc64le architecture ([#5459](https://github.com/opensearch-project/OpenSearch/pull/5459))
+- Add a setting to control auto release of OpenSearch managed index creation block ([#6277](https://github.com/opensearch-project/OpenSearch/pull/6277))
+- Fix timeout error when adding a document to an index with extension running ([#6275](https://github.com/opensearch-project/OpenSearch/pull/6275))
+- Handle translog upload during primary relocation for remote-backed indexes ([#5804](https://github.com/opensearch-project/OpenSearch/pull/5804))
+- Batch translog sync/upload per x ms for remote-backed indexes ([#5854](https://github.com/opensearch-project/OpenSearch/pull/5854))
+
+### Dependencies
+- Update nebula-publishing-plugin to 19.2.0 ([#5704](https://github.com/opensearch-project/OpenSearch/pull/5704))
+- Bump `reactor-netty` from 1.1.1 to 1.1.2 ([#5878](https://github.com/opensearch-project/OpenSearch/pull/5878))
+- OpenJDK Update (January 2023 Patch releases) ([#6075](https://github.com/opensearch-project/OpenSearch/pull/6075))
+- Bump `Mockito` from 4.7.0 to 5.1.0, `ByteBuddy` from 1.12.18 to 1.12.22 ([#6088](https://github.com/opensearch-project/OpenSearch/pull/6088))
+- Bump `joda` from 2.10.13 to 2.12.2 ([#6095](https://github.com/opensearch-project/OpenSearch/pull/6095))
+- Upgrade to Lucene 9.5.0 ([#6078](https://github.com/opensearch-project/OpenSearch/pull/6078))
+- Bump antlr4 from 4.9.3 to 4.11.1 ([#6116](https://github.com/opensearch-project/OpenSearch/pull/6116))
+- Bump `Netty` from 4.1.86.Final to 4.1.87.Final ([#6130](https://github.com/opensearch-project/OpenSearch/pull/6130))
+- Bump `Jackson` from 2.14.1 to 2.14.2 ([#6129](https://github.com/opensearch-project/OpenSearch/pull/6129))
+- Bump `org.apache.ant:ant` from 1.10.12 to 1.10.13 ([#6306](https://github.com/opensearch-project/OpenSearch/pull/6306))
+- Bump `azure-core-http-netty` from 1.12.7 to 1.12.8 ([#6304](https://github.com/opensearch-project/OpenSearch/pull/6304))
+- Bump `com.azure:azure-storage-common` from 12.18.1 to 12.19.3 ([#6304](https://github.com/opensearch-project/OpenSearch/pull/6304))
+- Bump `reactor-netty-http` from 1.0.24 to 1.1.2 ([#6309](https://github.com/opensearch-project/OpenSearch/pull/6309))
+- Bump `com.google.protobuf:protobuf-java` from 3.21.12 to 3.22.0 ([#6387](https://github.com/opensearch-project/OpenSearch/pull/6387))
+- Bump `io.projectreactor.netty:reactor-netty` from 1.1.2 to 1.1.3 ([#6386](https://github.com/opensearch-project/OpenSearch/pull/6386))
+- Bump `com.diffplug.spotless` from 6.10.0 to 6.15.0 ([#6385](https://github.com/opensearch-project/OpenSearch/pull/6385))
+- Bump `jettison` from 1.5.1 to 1.5.3 ([#6391](https://github.com/opensearch-project/OpenSearch/pull/6391))
+
+### Changed
+- Use ReplicationFailedException instead of OpensearchException in ReplicationTarget ([#4725](https://github.com/opensearch-project/OpenSearch/pull/4725))
+- [Refactor] Use local opensearch.common.SetOnce instead of lucene's utility class ([#5947](https://github.com/opensearch-project/OpenSearch/pull/5947))
+- Cluster health call to throw decommissioned exception for local decommissioned node([#6008](https://github.com/opensearch-project/OpenSearch/pull/6008))
+- [Refactor] core.common to new opensearch-common library ([#5976](https://github.com/opensearch-project/OpenSearch/pull/5976))
+- Update API spec for cluster health API ([#6399](https://github.com/opensearch-project/OpenSearch/pull/6399))
+
+### Removed
+- Remove deprecated org.gradle.util.DistributionLocator usage ([#6212](https://github.com/opensearch-project/OpenSearch/pull/6212))
+
+### Fixed
+- [Segment Replication] Fix for peer recovery ([#5344](https://github.com/opensearch-project/OpenSearch/pull/5344))
+- Fix weighted shard routing state across search requests([#6004](https://github.com/opensearch-project/OpenSearch/pull/6004))
+- [Segment Replication] Fix bug where inaccurate sequence numbers are sent during replication ([#6122](https://github.com/opensearch-project/OpenSearch/pull/6122))
+- Enable numeric sort optimisation for few numerical sort types ([#6321](https://github.com/opensearch-project/OpenSearch/pull/6321))
+- Fix Opensearch repository-s3 plugin cannot read ServiceAccount token ([#6390](https://github.com/opensearch-project/OpenSearch/pull/6390)
diff --git a/release-notes/opensearch.release-notes-2.7.0.md b/release-notes/opensearch.release-notes-2.7.0.md
new file mode 100644
index 0000000000000..fb886029683a6
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.7.0.md
@@ -0,0 +1,62 @@
+## 2023-04-18 Version 2.7.0 Release Notes
+
+## [2.7]
+### Added
+- Add GeoTile and GeoHash Grid aggregations on GeoShapes. ([#5589](https://github.com/opensearch-project/OpenSearch/pull/5589))
+- Disallow multiple data paths for search nodes ([#6427](https://github.com/opensearch-project/OpenSearch/pull/6427))
+- [Segment Replication] Allocation and rebalancing based on average primary shard count per index ([#6422](https://github.com/opensearch-project/OpenSearch/pull/6422))
+- The truncation limit of the OpenSearchJsonLayout logger is now configurable ([#6569](https://github.com/opensearch-project/OpenSearch/pull/6569))
+- Add 'base_path' setting to File System Repository ([#6558](https://github.com/opensearch-project/OpenSearch/pull/6558))
+- Return success on DeletePits when no PITs exist. ([#6544](https://github.com/opensearch-project/OpenSearch/pull/6544))
+- Add initial search pipelines ([#6587](https://github.com/opensearch-project/OpenSearch/pull/6587))
+- Add node repurpose command for search nodes ([#6517](https://github.com/opensearch-project/OpenSearch/pull/6517))
+- Add wait_for_completion parameter to resize, open, and forcemerge APIs ([#6434](https://github.com/opensearch-project/OpenSearch/pull/6434))
+- [Segment Replication] Apply backpressure when replicas fall behind ([#6563](https://github.com/opensearch-project/OpenSearch/pull/6563))
+- [Remote Store] Integrate remote segment store in peer recovery flow ([#6664](https://github.com/opensearch-project/OpenSearch/pull/6664))
+- Enable sort optimization for all NumericTypes ([#6464](https://github.com/opensearch-project/OpenSearch/pull/6464)
+- Remove 'cluster_manager' role attachment when using 'node.master' deprecated setting ([#6331](https://github.com/opensearch-project/OpenSearch/pull/6331))
+- Add new cluster settings to ignore weighted round-robin routing and fallback to default behaviour. ([#6834](https://github.com/opensearch-project/OpenSearch/pull/6834))
+- Add experimental support for ZSTD compression. ([#3577](https://github.com/opensearch-project/OpenSearch/pull/3577))
+- [Segment Replication] Add point in time and scroll query compatibility. ([#6644](https://github.com/opensearch-project/OpenSearch/pull/6644))
+- Add retry delay as dynamic setting for cluster maanger throttling. ([#6998](https://github.com/opensearch-project/OpenSearch/pull/6998))
+- Introduce full support for searchable snapshots ([#5087](https://github.com/opensearch-project/OpenSearch/issues/5087))
+- Introduce full support for Segment Replication ([#5147](https://github.com/opensearch-project/OpenSearch/issues/5147))
+- Introduce a new field type: flat_object to help prevent mapping explosions ([#1018](https://github.com/opensearch-project/OpenSearch/issues/1018))
+
+### Dependencies
+- Bump `org.apache.logging.log4j:log4j-core` from 2.18.0 to 2.20.0 ([#6490](https://github.com/opensearch-project/OpenSearch/pull/6490))
+- Bump `com.azure:azure-storage-common` from 12.19.3 to 12.20.0 ([#6492](https://github.com/opensearch-project/OpenSearch/pull/6492)
+- Bump `snakeyaml` from 1.33 to 2.0 ([#6511](https://github.com/opensearch-project/OpenSearch/pull/6511))
+- Bump `io.projectreactor.netty:reactor-netty` from 1.1.3 to 1.1.4
+- Bump `com.avast.gradle:gradle-docker-compose-plugin` from 0.15.2 to 0.16.11
+- Bump `net.minidev:json-smart` from 2.4.8 to 2.4.9
+- Bump `com.google.protobuf:protobuf-java` to 3.22.2 ([#6994](https://github.com/opensearch-project/OpenSearch/pull/6994))
+- Bump Netty to 4.1.90.Final ([#6677](https://github.com/opensearch-project/OpenSearch/pull/6677)
+- Bump `com.diffplug.spotless` from 6.15.0 to 6.17.0
+- Bump `org.apache.zookeeper:zookeeper` from 3.8.0 to 3.8.1
+- Bump `net.minidev:json-smart` from 2.4.7 to 2.4.10
+- Bump `org.apache.maven:maven-model` from 3.6.2 to 3.9.1
+- Bump `org.codehaus.jettison:jettison` from 1.5.3 to 1.5.4 ([#6878](https://github.com/opensearch-project/OpenSearch/pull/6878))
+- Add `com.github.luben:zstd-jni:1.5.5-1` ([#3577](https://github.com/opensearch-project/OpenSearch/pull/3577))
+- Bump: Netty from 4.1.90.Final to 4.1.91.Final , ASM 9.4 to ASM 9.5, ByteBuddy 1.14.2 to 1.14.3 ([#6981](https://github.com/opensearch-project/OpenSearch/pull/6981))
+- Bump `com.azure:azure-storage-blob` from 12.15.0 to 12.21.1
+- Bump `org.gradle.test-retry` from 1.5.1 to 1.5.2
+- Bump `org.apache.hadoop:hadoop-minicluster` from 3.3.4 to 3.3.5
+
+### Changed
+- Require MediaType in Strings.toString API ([#6009](https://github.com/opensearch-project/OpenSearch/pull/6009))
+- [Refactor] XContent base classes from xcontent to core library ([#5902](https://github.com/opensearch-project/OpenSearch/pull/5902))
+- Changed `opensearch-env` to respect already set `OPENSEARCH_HOME` environment variable ([#6956](https://github.com/opensearch-project/OpenSearch/pull/6956/))
+- Increased visibility of BaseRestHandler’s `unrecognized` method using a new public `unrecognizedStrings` method. ([#7125](https://github.com/opensearch-project/OpenSearch/pull/7125))
+
+### Deprecated
+- Map, List, and Set in org.opensearch.common.collect ([#6609](https://github.com/opensearch-project/OpenSearch/pull/6609))
+
+### Fixed
+- Added depth check in doc parser for deep nested document ([#5199](https://github.com/opensearch-project/OpenSearch/pull/5199))
+- Added equals/hashcode for named DocValueFormat.DateTime inner class ([#6357](https://github.com/opensearch-project/OpenSearch/pull/6357))
+- Fixed bug for searchable snapshot to take 'base_path' of blob into account ([#6558](https://github.com/opensearch-project/OpenSearch/pull/6558))
+- Fix fuzziness validation ([#5805](https://github.com/opensearch-project/OpenSearch/pull/5805))
+- Avoid negative memory result in IndicesQueryCache stats calculation ([#6917](https://github.com/opensearch-project/OpenSearch/pull/6917))
+- Fix GetSnapshots to not return non-existent snapshots with ignore_unavailable=true ([#6839](https://github.com/opensearch-project/OpenSearch/pull/6839))
+- Fix GlobalAggregation with profile option enabled returns incorrect result ([#7114](https://github.com/opensearch-project/OpenSearch/pull/7114))
diff --git a/release-notes/opensearch.release-notes-2.8.0.md b/release-notes/opensearch.release-notes-2.8.0.md
new file mode 100644
index 0000000000000..556e1f0047595
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.8.0.md
@@ -0,0 +1,71 @@
+## 2023-06-06 Version 2.8.0 Release Notes
+
+## [2.8]
+### Added
+- [Extensions] Moving Extensions APIs to support cross versions via protobuf. ([#7402](https://github.com/opensearch-project/OpenSearch/issues/7402))
+- [Extensions] Add IdentityPlugin into core to support Extension identities ([#7246](https://github.com/opensearch-project/OpenSearch/pull/7246))
+- Add connectToNodeAsExtension in TransportService ([#6866](https://github.com/opensearch-project/OpenSearch/pull/6866))
+- [Search Pipelines] Accept pipelines defined in search source ([#7253](https://github.com/opensearch-project/OpenSearch/pull/7253))
+- [Search Pipelines] Add `default_search_pipeline` index setting ([#7470](https://github.com/opensearch-project/OpenSearch/pull/7470))
+- [Search Pipelines] Add RenameFieldResponseProcessor for Search Pipelines ([#7377](https://github.com/opensearch-project/OpenSearch/pull/7377))
+- [Search Pipelines] Split search pipeline processor factories by type ([#7597](https://github.com/opensearch-project/OpenSearch/pull/7597))
+- [Search Pipelines] Add script processor ([#7607](https://github.com/opensearch-project/OpenSearch/pull/7607))
+- Add 'unsigned_long' numeric field type ([#6237](https://github.com/opensearch-project/OpenSearch/pull/6237))
+- Add back primary shard preference for queries ([#7375](https://github.com/opensearch-project/OpenSearch/pull/7375))
+- Add task cancellation timestamp in task API ([#7455](https://github.com/opensearch-project/OpenSearch/pull/7455))
+- Adds ExtensionsManager.lookupExtensionSettingsById ([#7466](https://github.com/opensearch-project/OpenSearch/pull/7466))
+- SegRep with Remote: Add hook for publishing checkpoint notifications after segment upload to remote store ([#7394](https://github.com/opensearch-project/OpenSearch/pull/7394))
+- Add search_after query optimizations with shard/segment short cutting ([#7453](https://github.com/opensearch-project/OpenSearch/pull/7453))
+- Provide mechanism to configure XContent parsing constraints (after update to Jackson 2.15.0 and above) ([#7550](https://github.com/opensearch-project/OpenSearch/pull/7550))
+- Support to clear filecache using clear indices cache API ([#7498](https://github.com/opensearch-project/OpenSearch/pull/7498))
+- Create NamedRoute to map extension routes to a shortened name ([#6870](https://github.com/opensearch-project/OpenSearch/pull/6870))
+- Added @dbwiddis as on OpenSearch maintainer ([#7665](https://github.com/opensearch-project/OpenSearch/pull/7665))
+- [Extensions] Add ExtensionAwarePlugin extension point to add custom settings for extensions ([#7526](https://github.com/opensearch-project/OpenSearch/pull/7526))
+- Add new cluster setting to set default index replication type ([#7420](https://github.com/opensearch-project/OpenSearch/pull/7420))
+
+### Dependencies
+- Bump `com.netflix.nebula:gradle-info-plugin` from 12.0.0 to 12.1.3 (#7564)
+- Bump `com.netflix.nebula:nebula-publishing-plugin` from 19.2.0 to 20.2.0
+- Bump `com.google.protobuf:protobuf-java` from 3.22.2 to 3.22.3
+- Bump `jackson` from 2.14.2 to 2.15.0 ([#7286](https://github.com/opensearch-project/OpenSearch/pull/7286))
+- Bump `com.netflix.nebula:nebula-publishing-plugin` from 20.2.0 to 20.3.0
+- Bump `com.netflix.nebula.ospackage-base` from 11.0.0 to 11.3.0
+- Bump `gradle.plugin.com.github.johnrengelman:shadow` from 7.1.2 to 8.0.0
+- Bump `jna` from 5.11.0 to 5.13.0
+- Bump `commons-io:commons-io` from 2.7 to 2.12.0 (#7661, #7658, #7656)
+- Bump `org.apache.shiro:shiro-core` from 1.9.1 to 1.11.0 ([#7397](https://github.com/opensearch-project/OpenSearch/pull/7397))
+- Bump `jetty-server` in hdfs-fixture from 9.4.49.v20220914 to 9.4.51.v20230217 ([#7405](https://github.com/opensearch-project/OpenSearch/pull/7405))
+- OpenJDK Update (April 2023 Patch releases) ([#7448](https://github.com/opensearch-project/OpenSearch/pull/7448)
+- Bump `org.apache.commons:commons-compress` from 1.22 to 1.23.0 (#7462)
+- Bump `com.azure:azure-core` from 1.34.0 to 1.39.0
+- Bump `com.networknt:json-schema-validator` from 1.0.78 to 1.0.81 (#7460)
+- Bump Apache Lucene to 9.6.0 ([#7505](https://github.com/opensearch-project/OpenSearch/pull/7505))
+- Bump `com.google.cloud:google-cloud-core-http` from 1.93.3 to 2.17.0 (#7488)
+- Bump `com.google.guava:guava` from 30.1.1-jre to 32.0.0-jre (#7565, #7811, #7808, #7807)
+- Bump `com.azure:azure-storage-common` from 12.20.0 to 12.21.1 (#7566, #7814)
+- Bump `org.apache.commons:commons-compress` from 1.22 to 1.23.0 (#7563)
+- Bump `jackson` from 2.15.0 to 2.15.1 ([#7603](https://github.com/opensearch-project/OpenSearch/pull/7603))
+- Bump `net.minidev:json-smart` from 2.4.10 to 2.4.11 (#7660, #7812)
+- Bump `io.projectreactor.netty:reactor-netty-core` from 1.1.5 to 1.1.7 (#7657)
+- Bump `org.apache.maven:maven-model` from 3.9.1 to 3.9.2 (#7655)
+- Bump `com.google.api:gax` from 2.17.0 to 2.27.0 (#7697)
+- Bump `io.projectreactor.netty:reactor-netty` from 1.1.4 to 1.1.7 ([#7725](https://github.com/opensearch-project/OpenSearch/pull/7725))
+- Bump `io.projectreactor.netty:reactor-netty-http` from 1.1.4 to 1.1.7 ([#7725](https://github.com/opensearch-project/OpenSearch/pull/7725))
+- Bump `com.google.http-client:google-http-client-appengine` from 1.41.8 to 1.43.2 (#7813)
+- Bump `org.gradle.test-retry` from 1.5.2 to 1.5.3 (#7810)
+
+### Changed
+- Enable `./gradlew build` on MacOS by disabling bcw tests ([#7303](https://github.com/opensearch-project/OpenSearch/pull/7303))
+- Moved concurrent-search from sandbox plugin to server module behind feature flag ([#7203](https://github.com/opensearch-project/OpenSearch/pull/7203))
+- Allow access to indices cache clear APIs for read only indexes ([#7303](https://github.com/opensearch-project/OpenSearch/pull/7303))
+- Changed concurrent-search threadpool type to be resizable and support task resource tracking ([#7502](https://github.com/opensearch-project/OpenSearch/pull/7502))
+- Default search preference to _primary for searchable snapshot indices ([#7628](https://github.com/opensearch-project/OpenSearch/pull/7628))
+- [Segment Replication] Remove codec name string match check for checkpoints ([#7741](https://github.com/opensearch-project/OpenSearch/pull/7741))
+
+### Fixed
+- Add more index blocks check for resize APIs ([#6774](https://github.com/opensearch-project/OpenSearch/pull/6774))
+- Replaces ZipInputStream with ZipFile to fix Zip Slip vulnerability ([#7230](https://github.com/opensearch-project/OpenSearch/pull/7230))
+- Add missing validation/parsing of SearchBackpressureMode of SearchBackpressureSettings ([#7541](https://github.com/opensearch-project/OpenSearch/pull/7541))
+- [Search Pipelines] Better exception handling in search pipelines ([#7735](https://github.com/opensearch-project/OpenSearch/pull/7735))
+- Fix input validation in segments and delete pit request ([#6645](https://github.com/opensearch-project/OpenSearch/pull/6645))
+
diff --git a/release-notes/opensearch.release-notes-2.9.0.md b/release-notes/opensearch.release-notes-2.9.0.md
new file mode 100644
index 0000000000000..76d2d9f4593d6
--- /dev/null
+++ b/release-notes/opensearch.release-notes-2.9.0.md
@@ -0,0 +1,109 @@
+## 2023-07-13 Version 2.9.0 Release Notes
+
+## [2.9]
+
+### Added
+- [SearchPipeline] Add new search pipeline processor type, SearchPhaseResultsProcessor, that can modify the result of one search phase before starting the next phase.([#7283](https://github.com/opensearch-project/OpenSearch/pull/7283))
+- Add task cancellation monitoring service ([#7642](https://github.com/opensearch-project/OpenSearch/pull/7642))
+- Add TokenManager Interface ([#7452](https://github.com/opensearch-project/OpenSearch/pull/7452))
+- Add Remote store as a segment replication source ([#7653](https://github.com/opensearch-project/OpenSearch/pull/7653))
+- Implement concurrent aggregations support without profile option ([#7514](https://github.com/opensearch-project/OpenSearch/pull/7514))
+- Add dynamic index and cluster setting for concurrent segment search ([#7956](https://github.com/opensearch-project/OpenSearch/pull/7956))
+- Add descending order search optimization through reverse segment read. ([#7967](https://github.com/opensearch-project/OpenSearch/pull/7967))
+- [Search pipelines] Added search pipelines output to node stats ([#8053](https://github.com/opensearch-project/OpenSearch/pull/8053))
+- Update components of segrep backpressure to support remote store. ([#8020](https://github.com/opensearch-project/OpenSearch/pull/8020))
+- Make remote cluster connection setup in async ([#8038](https://github.com/opensearch-project/OpenSearch/pull/8038))
+- Add API to initialize extensions ([#8029]()https://github.com/opensearch-project/OpenSearch/pull/8029)
+- Add distributed tracing framework ([#7543](https://github.com/opensearch-project/OpenSearch/issues/7543))
+- Enable Point based optimization for custom comparators ([#8168](https://github.com/opensearch-project/OpenSearch/pull/8168))
+- [Extensions] Support extension additional settings with extension REST initialization ([#8414](https://github.com/opensearch-project/OpenSearch/pull/8414))
+- Adds mock implementation for TelemetryPlugin ([#7545](https://github.com/opensearch-project/OpenSearch/issues/7545))
+- Support transport action names when registering NamedRoutes ([#7957](https://github.com/opensearch-project/OpenSearch/pull/7957))
+- Create concept of persistent ThreadContext headers that are unstashable ([#8291]()https://github.com/opensearch-project/OpenSearch/pull/8291)
+- [Search pipelines] Add Global Ignore_failure options for Processors ([#8373](https://github.com/opensearch-project/OpenSearch/pull/8373))
+- Enable Partial Flat Object ([#7997](https://github.com/opensearch-project/OpenSearch/pull/7997))
+- Add jdk.incubator.vector module support for JDK 20+ ([#8601](https://github.com/opensearch-project/OpenSearch/pull/8601))
+- Introduce full support for Search Pipeline ([#8613](https://github.com/opensearch-project/OpenSearch/pull/8613))
+- Add partial results support for concurrent segment search ([#8306](https://github.com/opensearch-project/OpenSearch/pull/8306))
+
+### Dependencies
+- Bump `com.azure:azure-storage-common` from 12.21.0 to 12.21.1 (#7566, #7814)
+- Bump `com.google.guava:guava` from 30.1.1-jre to 32.1.1-jre (#7565, #7811, #7807, #7808, #8402, #8400, #8401, #8581)
+- Bump `net.minidev:json-smart` from 2.4.10 to 2.4.11 (#7660, #7812)
+- Bump `org.gradle.test-retry` from 1.5.2 to 1.5.3 (#7810)
+- Bump `com.diffplug.spotless` from 6.17.0 to 6.18.0 (#7896)
+- Bump `jackson` from 2.15.1 to 2.15.2 ([#7897](https://github.com/opensearch-project/OpenSearch/pull/7897))
+- Add `com.github.luben:zstd-jni` version 1.5.5-3 ([#2996](https://github.com/opensearch-project/OpenSearch/pull/2996))
+- Bump `netty` from 4.1.91.Final to 4.1.93.Final ([#7901](https://github.com/opensearch-project/OpenSearch/pull/7901))
+- Bump `com.amazonaws` 1.12.270 to `software.amazon.awssdk` 2.20.55 ([7372](https://github.com/opensearch-project/OpenSearch/pull/7372/))
+- Add `org.reactivestreams` 1.0.4 ([7372](https://github.com/opensearch-project/OpenSearch/pull/7372/))
+- Bump `com.networknt:json-schema-validator` from 1.0.81 to 1.0.85 ([7968], #8255)
+- Bump `com.netflix.nebula:gradle-extra-configurations-plugin` from 9.0.0 to 10.0.0 in /buildSrc ([#7068](https://github.com/opensearch-project/OpenSearch/pull/7068))
+- Bump `com.google.guava:guava` from 32.0.0-jre to 32.0.1-jre (#8009)
+- Bump `commons-io:commons-io` from 2.12.0 to 2.13.0 (#8014, #8013, #8010)
+- Bump `com.diffplug.spotless` from 6.18.0 to 6.19.0 (#8007)
+- Bump `'com.azure:azure-storage-blob` to 12.22.2 from 12.21.1 ([#8043](https://github.com/opensearch-project/OpenSearch/pull/8043))
+- Bump `org.jruby.joni:joni` from 2.1.48 to 2.2.1 (#8015, #8254)
+- Bump `com.google.guava:guava` from 32.0.0-jre to 32.0.1-jre ([#8011](https://github.com/opensearch-project/OpenSearch/pull/8011), [#8012](https://github.com/opensearch-project/OpenSearch/pull/8012), [#8107](https://github.com/opensearch-project/OpenSearch/pull/8107))
+- Bump `io.projectreactor:reactor-core` from 3.4.18 to 3.5.6 in /plugins/repository-azure ([#8016](https://github.com/opensearch-project/OpenSearch/pull/8016))
+- Bump `spock-core` from 2.1-groovy-3.0 to 2.3-groovy-3.0 ([#8122](https://github.com/opensearch-project/OpenSearch/pull/8122))
+- Bump `com.networknt:json-schema-validator` from 1.0.83 to 1.0.84 (#8141)
+- Bump `com.netflix.nebula:gradle-info-plugin` from 12.1.3 to 12.1.5 (#8139, #8568)
+- Bump `commons-io:commons-io` from 2.12.0 to 2.13.0 in /plugins/discovery-azure-classic ([#8140](https://github.com/opensearch-project/OpenSearch/pull/8140))
+- Bump `mockito` from 5.2.0 to 5.4.0 ([#8181](https://github.com/opensearch-project/OpenSearch/pull/8181))
+- Bump `netty` from 4.1.93.Final to 4.1.94.Final ([#8191](https://github.com/opensearch-project/OpenSearch/pull/8191))
+- Bump `org.apache.hadoop:hadoop-minicluster` from 3.3.5 to 3.3.6 (#8257)
+- Bump `io.projectreactor.netty:reactor-netty-http` from 1.1.7 to 1.1.8 (#8256)
+- [Upgrade] Lucene 9.7.0 release (#8272)
+- Bump `org.jboss.resteasy:resteasy-jackson2-provider` from 3.0.26.Final to 6.2.4.Final in /qa/wildfly ([#8209](https://github.com/opensearch-project/OpenSearch/pull/8209))
+- Bump `com.google.api-client:google-api-client` from 1.34.0 to 2.2.0 ([#8276](https://github.com/opensearch-project/OpenSearch/pull/8276))
+- Update Apache HttpCore/ HttpClient and Apache HttpCore5 / HttpClient5 dependencies ([#8434](https://github.com/opensearch-project/OpenSearch/pull/8434))
+- Bump `org.apache.maven:maven-model` from 3.9.2 to 3.9.3 (#8403)
+- Bump `io.projectreactor.netty:reactor-netty` and `io.projectreactor.netty:reactor-netty-core` from 1.1.7 to 1.1.8 (#8405)
+- Bump `com.azure:azure-storage-blob` from 12.22.2 to 12.22.3 (#8572)
+- Bump `net.minidev:json-smart` from 2.4.11 to 2.5.0 (#8575, #8576)
+- Bump `com.google.jimfs:jimfs` from 1.2 to 1.3.0 (#8577, #8571)
+- Bump `com.networknt:json-schema-validator` from 1.0.85 to 1.0.86 ([#8573](https://github.com/opensearch-project/OpenSearch/pull/8573))
+- Bump `com.google.cloud:google-cloud-core-http` from 2.17.0 to 2.21.0 ([#8586](https://github.com/opensearch-project/OpenSearch/pull/8586))
+- Bump `com.google.jimfs:jimfs` from 1.2 to 1.3.0 ([#8585](https://github.com/opensearch-project/OpenSearch/pull/8585))
+
+### Changed
+- Replace jboss-annotations-api_1.2_spec with jakarta.annotation-api ([#7836](https://github.com/opensearch-project/OpenSearch/pull/7836))
+- Reduce memory copy in zstd compression ([#7681](https://github.com/opensearch-project/OpenSearch/pull/7681))
+- Add min, max, average and thread info to resource stats in tasks API ([#7673](https://github.com/opensearch-project/OpenSearch/pull/7673))
+- Add ZSTD compression for snapshotting ([#2996](https://github.com/opensearch-project/OpenSearch/pull/2996))
+- Change `com.amazonaws.sdk.ec2MetadataServiceEndpointOverride` to `aws.ec2MetadataServiceEndpoint` ([7372](https://github.com/opensearch-project/OpenSearch/pull/7372/))
+- Change `com.amazonaws.sdk.stsEndpointOverride` to `aws.stsEndpointOverride` ([7372](https://github.com/opensearch-project/OpenSearch/pull/7372/))
+- Add new query profile collector fields with concurrent search execution ([#7898](https://github.com/opensearch-project/OpenSearch/pull/7898))
+- Align range and default value for deletes_pct_allowed in merge policy ([#7730](https://github.com/opensearch-project/OpenSearch/pull/7730))
+- Rename QueryPhase actors like Suggest, Rescore to be processors rather than phase ([#8025](https://github.com/opensearch-project/OpenSearch/pull/8025))
+- Compress and cache cluster state during validate join request ([#7321](https://github.com/opensearch-project/OpenSearch/pull/7321))
+- [Snapshot Interop] Add Changes in Create Snapshot Flow for remote store interoperability. ([#7118](https://github.com/opensearch-project/OpenSearch/pull/7118))
+- Allow insecure string settings to warn-log usage and advise to migration of a newer secure variant ([#5496](https://github.com/opensearch-project/OpenSearch/pull/5496))
+- Add self-organizing hash table to improve the performance of bucket aggregations ([#7652](https://github.com/opensearch-project/OpenSearch/pull/7652))
+- Check UTF16 string size before converting to String to avoid OOME ([#7963](https://github.com/opensearch-project/OpenSearch/pull/7963))
+- Move ZSTD compression codecs out of the sandbox ([#7908](https://github.com/opensearch-project/OpenSearch/pull/7908))
+- Update ZSTD default compression level ([#8471](https://github.com/opensearch-project/OpenSearch/pull/8471))
+- [Search Pipelines] Pass pipeline creation context to processor factories ([#8164](https://github.com/opensearch-project/OpenSearch/pull/8164))
+- Enabling compression levels for zstd and zstd_no_dict ([#8312](https://github.com/opensearch-project/OpenSearch/pull/8312))
+- Optimize Metadata build() to skip redundant computations as part of ClusterState build ([#7853](https://github.com/opensearch-project/OpenSearch/pull/7853))
+- Add safeguard limits for file cache during node level allocation ([#8208](https://github.com/opensearch-project/OpenSearch/pull/8208))
+- Move span actions to Scope ([#8411](https://github.com/opensearch-project/OpenSearch/pull/8411))
+- Add wrapper tracer implementation ([#8565](https://github.com/opensearch-project/OpenSearch/pull/8565))
+- Improved performance of parsing floating point numbers ([#7909](https://github.com/opensearch-project/OpenSearch/pull/7909))
+
+### Removed
+- Remove `COMPRESSOR` variable from `CompressorFactory` and use `DEFLATE_COMPRESSOR` instead ([7907](https://github.com/opensearch-project/OpenSearch/pull/7907))
+- Remove concurrency based minimum file cache size restriction ([#8294](https://github.com/opensearch-project/OpenSearch/pull/8294))
+
+### Fixed
+- Fixing error: adding a new/forgotten parameter to the configuration for checking the config on startup in plugins/repository-s3 #7924
+- Enforce 512 byte document ID limit in bulk updates ([#8039](https://github.com/opensearch-project/OpenSearch/pull/8039))
+- With only GlobalAggregation in request causes unnecessary wrapping with MultiCollector ([#8125](https://github.com/opensearch-project/OpenSearch/pull/8125))
+- Fix mapping char_filter when mapping a hashtag ([#7591](https://github.com/opensearch-project/OpenSearch/pull/7591))
+- Fix NPE in multiterms aggregations involving empty buckets ([#7318](https://github.com/opensearch-project/OpenSearch/pull/7318))
+- Precise system clock time in MasterService debug logs ([#7902](https://github.com/opensearch-project/OpenSearch/pull/7902))
+- Improve indexing performance for flat_object type ([#7855](https://github.com/opensearch-project/OpenSearch/pull/7855))
+- Adds log4j configuration for telemetry LogSpanExporter ([#8393](https://github.com/opensearch-project/OpenSearch/pull/8393))
+- Fix painless casting bug, which crashes the OpenSearch process ([#8315](https://github.com/opensearch-project/OpenSearch/pull/8315))
+- Add missing validation/parsing of SearchBackpressureMode of SearchBackpressureSettings ([#7541](https://github.com/opensearch-project/OpenSearch/pull/7541))
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/bulk.json b/rest-api-spec/src/main/resources/rest-api-spec/api/bulk.json
index f7c0d69805caf..bb066cd131480 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/bulk.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/bulk.json
@@ -26,23 +26,6 @@
               "description":"Default index for items which don't provide one"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/_bulk",
-          "methods":[
-            "POST",
-            "PUT"
-          ],
-          "parts":{
-            "index":{
-              "type":"string",
-              "description":"Default index for items which don't provide one"
-            },
-            "type":{
-              "type":"string",
-              "description":"Default document type for items which don't provide one"
-            }
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.allocation.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.allocation.json
index 7b3dc70b03c38..717c1c49808f6 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.allocation.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.allocation.json
@@ -55,7 +55,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.cluster_manager.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.cluster_manager.json
index c1084825546bf..cd96038ad0693 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.cluster_manager.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.cluster_manager.json
@@ -36,7 +36,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.indices.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.indices.json
index a92189134f88f..2491ab309531d 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.indices.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.indices.json
@@ -55,7 +55,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.nodeattrs.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.nodeattrs.json
index e688e23cab089..c8afa4cb17039 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.nodeattrs.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.nodeattrs.json
@@ -26,7 +26,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.pending_tasks.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.pending_tasks.json
index 36fa33be495cd..9c0edf8c53d90 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.pending_tasks.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.pending_tasks.json
@@ -26,7 +26,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.plugins.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.plugins.json
index d5346c6d9e7b4..0b5b39b01ee58 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.plugins.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.plugins.json
@@ -26,7 +26,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.repositories.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.repositories.json
index 84d9965907ff3..58960709a99bb 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.repositories.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.repositories.json
@@ -27,7 +27,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segment_replication.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segment_replication.json
new file mode 100644
index 0000000000000..a815cd5b1101b
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segment_replication.json
@@ -0,0 +1,103 @@
+{
+  "cat.segment_replication":{
+    "documentation":{
+      "url":"https://github.com/opensearch-project/documentation-website/issues/2627",
+      "description":"Returns information about both on-going and latest completed Segment Replication events"
+    },
+    "stability":"experimental",
+    "url":{
+      "paths":[
+        {
+          "path":"/_cat/segment_replication",
+          "methods":[
+            "GET"
+          ]
+        },
+        {
+          "path":"/_cat/segment_replication/{index}",
+          "methods":[
+            "GET"
+          ],
+          "parts":{
+            "index":{
+              "type":"list",
+              "description":"Comma-separated list or wildcard expression of index names to limit the returned information"
+            }
+          }
+        }
+      ]
+    },
+    "params":{
+      "format":{
+        "type":"string",
+        "description":"a short version of the Accept header, e.g. json, yaml"
+      },
+      "active_only":{
+        "type":"boolean",
+        "description":"If `true`, the response only includes ongoing segment replication events",
+        "default":false
+      },
+      "bytes":{
+        "type":"enum",
+        "description":"The unit in which to display byte values",
+        "options":[
+          "b",
+          "k",
+          "kb",
+          "m",
+          "mb",
+          "g",
+          "gb",
+          "t",
+          "tb",
+          "p",
+          "pb"
+        ]
+      },
+      "detailed":{
+        "type":"boolean",
+        "description":"If `true`, the response includes detailed information about segment replications",
+        "default":false
+      },
+      "shards":{
+        "type":"list",
+        "description":"Comma-separated list of shards to display"
+      },
+      "h":{
+        "type":"list",
+        "description":"Comma-separated list of column names to display"
+      },
+      "help":{
+        "type":"boolean",
+        "description":"Return help information",
+        "default":false
+      },
+      "index":{
+        "type":"list",
+        "description":"Comma-separated list or wildcard expression of index names to limit the returned information"
+      },
+      "s":{
+        "type":"list",
+        "description":"Comma-separated list of column names or column aliases to sort by"
+      },
+      "time":{
+        "type":"enum",
+        "description":"The unit in which to display time values",
+        "options":[
+          "d",
+          "h",
+          "m",
+          "s",
+          "ms",
+          "micros",
+          "nanos"
+        ]
+      },
+      "v":{
+        "type":"boolean",
+        "description":"Verbose mode. Display column headers",
+        "default":false
+      }
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segments.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segments.json
index 472ef7fd22eee..5107353c7b14f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segments.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.segments.json
@@ -49,6 +49,18 @@
           "pb"
         ]
       },
+      "master_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
+      },
       "h":{
         "type":"list",
         "description":"Comma-separated list of column names to display"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.shards.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.shards.json
index a13c0f6bf6d4a..fab381a098e3f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.shards.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.shards.json
@@ -55,7 +55,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.snapshots.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.snapshots.json
index 757c2cfbe7dc6..1320207abfe75 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.snapshots.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.snapshots.json
@@ -39,7 +39,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.templates.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.templates.json
index 53fc872b5dae2..d45593b7bb2c8 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.templates.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.templates.json
@@ -38,7 +38,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.thread_pool.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.thread_pool.json
index 710c297dbbe75..1165703490d1a 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cat.thread_pool.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cat.thread_pool.json
@@ -54,7 +54,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "h":{
         "type":"list",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_component_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_component_template.json
index 9beea52c86b37..43e14ad0e2dd8 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_component_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_component_template.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_decommission_awareness.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_decommission_awareness.json
new file mode 100644
index 0000000000000..13ea101169e60
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_decommission_awareness.json
@@ -0,0 +1,19 @@
+{
+  "cluster.delete_decommission_awareness": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/decommission/",
+      "description": "Delete any existing decommission."
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path": "/_cluster/decommission/awareness/",
+          "methods": [
+            "DELETE"
+          ]
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_weighted_routing.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_weighted_routing.json
new file mode 100644
index 0000000000000..274c32f2a91be
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.delete_weighted_routing.json
@@ -0,0 +1,19 @@
+{
+  "cluster.delete_weighted_routing": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/weighted-routing/delete",
+      "description": "Delete weighted shard routing weights"
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path": "/_cluster/routing/awareness/weights",
+          "methods": [
+            "DELETE"
+          ]
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_component_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_component_template.json
index ecf32f50c0a6c..aa4e395672ef3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_component_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_component_template.json
@@ -30,7 +30,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "local":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_decommission_awareness.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_decommission_awareness.json
new file mode 100644
index 0000000000000..302dea4ec31a7
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_decommission_awareness.json
@@ -0,0 +1,25 @@
+{
+  "cluster.get_decommission_awareness": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/decommission/",
+      "description": "Get details and status of decommissioned attribute"
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path":"/_cluster/decommission/awareness/{awareness_attribute_name}/_status",
+          "methods":[
+            "GET"
+          ],
+          "parts":{
+            "awareness_attribute_name":{
+              "type":"string",
+              "description":"Awareness attribute name"
+            }
+          }
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_settings.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_settings.json
index 6f91fbbedf5de..c60230dbc43b3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_settings.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_settings.json
@@ -22,7 +22,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_weighted_routing.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_weighted_routing.json
new file mode 100644
index 0000000000000..95e776d2ffb8b
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.get_weighted_routing.json
@@ -0,0 +1,25 @@
+{
+  "cluster.get_weighted_routing": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/weighted-routing/get",
+      "description": "Fetches weighted shard routing weights"
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path": "/_cluster/routing/awareness/{attribute}/weights",
+          "methods": [
+            "GET"
+          ],
+          "parts": {
+            "attribute": {
+              "type": "string",
+              "description": "Awareness attribute name"
+            }
+          }
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.health.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.health.json
index 894b141f2f3b3..b96340d682546 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.health.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.health.json
@@ -45,7 +45,8 @@
         "options":[
           "cluster",
           "indices",
-          "shards"
+          "shards",
+          "awareness_attributes"
         ],
         "default":"cluster",
         "description":"Specify the level of detail for returned information"
@@ -56,7 +57,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
@@ -98,6 +107,14 @@
           "red"
         ],
         "description":"Wait until cluster is in a specific state"
+      },
+      "awareness_attribute":{
+        "type":"string",
+        "description":"The awareness attribute for which the health is required"
+      },
+      "ensure_node_weighed_in":{
+        "type":"boolean",
+        "description": "Ensures whether the local node is commissioned and weighed in or not. (default: false)"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.pending_tasks.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.pending_tasks.json
index d940adf9aef5d..22cfbac7ff447 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.pending_tasks.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.pending_tasks.json
@@ -22,7 +22,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_component_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_component_template.json
index abc83fb15f48a..05558bc7bfc50 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_component_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_component_template.json
@@ -34,7 +34,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_decommission_awareness.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_decommission_awareness.json
new file mode 100644
index 0000000000000..bf4ffd454d9df
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_decommission_awareness.json
@@ -0,0 +1,29 @@
+{
+  "cluster.put_decommission_awareness": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/decommission/",
+      "description": "Decommissions an awareness attribute"
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path": "/_cluster/decommission/awareness/{awareness_attribute_name}/{awareness_attribute_value}",
+          "methods": [
+            "PUT"
+          ],
+          "parts": {
+            "awareness_attribute_name": {
+              "type": "string",
+              "description": "Awareness attribute name"
+            },
+            "awareness_attribute_value": {
+              "type": "string",
+              "description": "Awareness attribute value"
+            }
+          }
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_settings.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_settings.json
index f6b9a0863380e..1e36acc51544d 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_settings.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_settings.json
@@ -22,7 +22,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_weighted_routing.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_weighted_routing.json
new file mode 100644
index 0000000000000..b8ce13ab33621
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.put_weighted_routing.json
@@ -0,0 +1,25 @@
+{
+  "cluster.put_weighted_routing": {
+    "documentation": {
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/weighted-routing/put",
+      "description": "Updates weighted shard routing weights"
+    },
+    "stability": "experimental",
+    "url": {
+      "paths": [
+        {
+          "path": "/_cluster/routing/awareness/{attribute}/weights",
+          "methods": [
+            "PUT"
+          ],
+          "parts": {
+            "attribute": {
+              "type": "string",
+              "description": "Awareness attribute name"
+            }
+          }
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.reroute.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.reroute.json
index bcf2704110664..285da40dd0245 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.reroute.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.reroute.json
@@ -44,7 +44,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.state.json b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.state.json
index c17e5b073e361..b43ab901785bd 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.state.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.state.json
@@ -71,7 +71,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "flat_settings":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/create.json b/rest-api-spec/src/main/resources/rest-api-spec/api/create.json
index 171f3da44d36d..767af84b82258 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/create.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/create.json
@@ -23,32 +23,6 @@
               "description":"The name of the index"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/{id}/_create",
-          "methods":[
-            "PUT",
-            "POST"
-          ],
-          "parts":{
-            "id":{
-              "type":"string",
-              "description":"Document ID"
-            },
-            "index":{
-              "type":"string",
-              "description":"The name of the index"
-            },
-            "type":{
-              "type":"string",
-              "description":"The type of the document",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/create_pit.json b/rest-api-spec/src/main/resources/rest-api-spec/api/create_pit.json
new file mode 100644
index 0000000000000..d3a2104c01bc0
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/create_pit.json
@@ -0,0 +1,44 @@
+
+{
+  "create_pit":{
+    "documentation":{
+      "url":"https://opensearch.org/docs/latest/opensearch/rest-api/point_in_time/",
+      "description":"Creates point in time context."
+    },
+    "stability":"stable",
+    "url":{
+      "paths":[
+        {
+          "path":"/{index}/_search/point_in_time",
+          "methods":[
+            "POST"
+          ],
+          "parts":{
+            "index":{
+              "type":"list",
+              "description":"A comma-separated list of index names to search; use `_all` or empty string to perform the operation on all indices"
+            }
+          }
+        }
+      ]
+    },
+    "params":{
+      "allow_partial_pit_creation":{
+        "type":"boolean",
+        "description":"Allow if point in time can be created with partial failures"
+      },
+      "keep_alive":{
+        "type":"string",
+        "description":"Specify the keep alive for point in time"
+      },
+      "preference":{
+        "type":"string",
+        "description":"Specify the node or shard the operation should be performed on (default: random)"
+      },
+      "routing":{
+        "type":"list",
+        "description":"A comma-separated list of specific routing values"
+      }
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.delete_dangling_index.json b/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.delete_dangling_index.json
index 1e3d74784591b..5d832fc794f4f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.delete_dangling_index.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.delete_dangling_index.json
@@ -30,9 +30,17 @@
         "type": "time",
         "description": "Explicit operation timeout"
       },
-      "master_timeout": {
-        "type": "time",
-        "description": "Specify timeout for connection to master"
+      "master_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.import_dangling_index.json b/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.import_dangling_index.json
index e9dce01a76727..5b056e1fa145f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.import_dangling_index.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/dangling_indices.import_dangling_index.json
@@ -30,9 +30,17 @@
         "type": "time",
         "description": "Explicit operation timeout"
       },
-      "master_timeout": {
-        "type": "time",
-        "description": "Specify timeout for connection to master"
+      "master_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/delete.json b/rest-api-spec/src/main/resources/rest-api-spec/api/delete.json
index 0d82bca9d4173..76dceb455627f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/delete.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/delete.json
@@ -22,31 +22,6 @@
               "description":"The name of the index"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/{id}",
-          "methods":[
-            "DELETE"
-          ],
-          "parts":{
-            "id":{
-              "type":"string",
-              "description":"The document ID"
-            },
-            "index":{
-              "type":"string",
-              "description":"The name of the index"
-            },
-            "type":{
-              "type":"string",
-              "description":"The type of the document",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/delete_all_pits.json b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_all_pits.json
new file mode 100644
index 0000000000000..5ff01aa746df9
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_all_pits.json
@@ -0,0 +1,19 @@
+{
+  "delete_all_pits":{
+    "documentation":{
+      "url":"https://opensearch.org/docs/latest/opensearch/rest-api/point_in_time/",
+      "description":"Deletes all active point in time searches."
+    },
+    "stability":"stable",
+    "url":{
+      "paths":[
+        {
+          "path":"/_search/point_in_time/_all",
+          "methods":[
+            "DELETE"
+          ]
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/delete_pit.json b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_pit.json
new file mode 100644
index 0000000000000..b54d9f76204f4
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_pit.json
@@ -0,0 +1,23 @@
+{
+  "delete_pit":{
+    "documentation":{
+      "url":"https://opensearch.org/docs/latest/opensearch/rest-api/point_in_time/",
+      "description":"Deletes one or more point in time searches based on the IDs passed."
+    },
+    "stability":"stable",
+    "url":{
+      "paths":[
+        {
+          "path":"/_search/point_in_time",
+          "methods":[
+            "DELETE"
+          ]
+        }
+      ]
+    },
+    "body":{
+      "description":"A comma-separated list of pit IDs to clear",
+      "required":true
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/delete_script.json b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_script.json
index b38b97ae57c2e..acaa389738606 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/delete_script.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/delete_script.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/exists_source.json b/rest-api-spec/src/main/resources/rest-api-spec/api/exists_source.json
index 143ee406025ce..bdbf818fb5d81 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/exists_source.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/exists_source.json
@@ -22,31 +22,6 @@
               "description":"The name of the index"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/{id}/_source",
-          "methods":[
-            "HEAD"
-          ],
-          "parts":{
-            "id":{
-              "type":"string",
-              "description":"The document ID"
-            },
-            "index":{
-              "type":"string",
-              "description":"The name of the index"
-            },
-            "type":{
-              "type":"string",
-              "description":"The type of the document; deprecated and optional starting with 7.0",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/explain.json b/rest-api-spec/src/main/resources/rest-api-spec/api/explain.json
index c7c393a6a1cba..7f630f7666f30 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/explain.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/explain.json
@@ -23,32 +23,6 @@
               "description":"The name of the index"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/{id}/_explain",
-          "methods":[
-            "GET",
-            "POST"
-          ],
-          "parts":{
-            "id":{
-              "type":"string",
-              "description":"The document ID"
-            },
-            "index":{
-              "type":"string",
-              "description":"The name of the index"
-            },
-            "type":{
-              "type":"string",
-              "description":"The type of the document",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/get_all_pits.json b/rest-api-spec/src/main/resources/rest-api-spec/api/get_all_pits.json
new file mode 100644
index 0000000000000..544a8cb11b002
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/get_all_pits.json
@@ -0,0 +1,19 @@
+{
+  "get_all_pits":{
+    "documentation":{
+      "url":"https://opensearch.org/docs/latest/opensearch/rest-api/point_in_time/",
+      "description":"Lists all active point in time searches."
+    },
+    "stability":"stable",
+    "url":{
+      "paths":[
+        {
+          "path":"/_search/point_in_time/_all",
+          "methods":[
+            "GET"
+          ]
+        }
+      ]
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/get_script.json b/rest-api-spec/src/main/resources/rest-api-spec/api/get_script.json
index 14307bea2ef0b..9cdac886b1b27 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/get_script.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/get_script.json
@@ -24,7 +24,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.add_block.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.add_block.json
index 7389fb1322824..af10b9f50091f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.add_block.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.add_block.json
@@ -32,7 +32,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clear_cache.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clear_cache.json
index 64c10a520c7c4..0c7eca8c8e6f5 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clear_cache.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clear_cache.json
@@ -67,6 +67,10 @@
       "request":{
         "type":"boolean",
         "description":"Clear request cache"
+      },
+      "file":{
+        "type":"boolean",
+        "description":"Clear filecache"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clone.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clone.json
index d3a249583bd84..2d874f4933768 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clone.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.clone.json
@@ -31,13 +31,29 @@
         "type" : "time",
         "description" : "Explicit operation timeout"
       },
-      "master_timeout": {
-        "type" : "time",
-        "description" : "Specify timeout for connection to master"
+      "master_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "wait_for_active_shards": {
         "type" : "string",
         "description" : "Set the number of active shards to wait for on the cloned index before the operation returns."
+      },
+      "wait_for_completion": {
+        "type" : "boolean",
+        "description" : "If false, the request will return a task immediately and the operation will run in background. Defaults to true."
+      },
+      "task_execution_timeout": {
+        "type" : "time",
+        "description" : "Explicit task execution timeout, only useful when wait_for_completion is false, defaults to 1h."
       }
     },
     "body": {
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.close.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.close.json
index f26c8e77a06a6..1182b73541f93 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.close.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.close.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.create.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.create.json
index 922183d628ac6..53ea4cbd80803 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.create.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.create.json
@@ -32,7 +32,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_alias.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_alias.json
index 13abf70ca739b..049a397c6b3e2 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_alias.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_alias.json
@@ -48,7 +48,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_index_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_index_template.json
index d037b03dc5277..c74771ffe4b81 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_index_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_index_template.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_template.json
index ca484a73e99f9..74dbb1822b64a 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.delete_template.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.exists_type.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.exists_type.json
deleted file mode 100644
index c854d0e8fd841..0000000000000
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.exists_type.json
+++ /dev/null
@@ -1,55 +0,0 @@
-{
-  "indices.exists_type":{
-    "documentation":{
-      "url":"https://www.elastic.co/guide/en/elasticsearch/reference/master/indices-types-exists.html",
-      "description":"Returns information about whether a particular document type exists. (DEPRECATED)"
-    },
-    "stability":"stable",
-    "url":{
-      "paths":[
-        {
-          "path":"/{index}/_mapping/{type}",
-          "methods":[
-            "HEAD"
-          ],
-          "parts":{
-            "index":{
-              "type":"list",
-              "description":"A comma-separated list of index names; use `_all` to check the types across all indices"
-            },
-            "type":{
-              "type":"list",
-              "description":"A comma-separated list of document types to check"
-            }
-          }
-        }
-      ]
-    },
-    "params":{
-      "ignore_unavailable":{
-        "type":"boolean",
-        "description":"Whether specified concrete indices should be ignored when unavailable (missing or closed)"
-      },
-      "allow_no_indices":{
-        "type":"boolean",
-        "description":"Whether to ignore if a wildcard indices expression resolves into no concrete indices. (This includes `_all` string or when no indices have been specified)"
-      },
-      "expand_wildcards":{
-        "type":"enum",
-        "options":[
-          "open",
-          "closed",
-          "hidden",
-          "none",
-          "all"
-        ],
-        "default":"open",
-        "description":"Whether to expand wildcard expression to concrete indices that are open, closed or both."
-      },
-      "local":{
-        "type":"boolean",
-        "description":"Return local information, do not retrieve the state from master node (default: false)"
-      }
-    }
-  }
-}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.forcemerge.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.forcemerge.json
index 6036b75bb83e4..02fbcc36dfe64 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.forcemerge.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.forcemerge.json
@@ -59,6 +59,10 @@
       "only_expunge_deletes":{
         "type":"boolean",
         "description":"Specify whether the operation should only expunge deleted documents"
+      },
+      "wait_for_completion": {
+        "type" : "boolean",
+        "description" : "If false, the request will return a task immediately and the operation will run in background. Defaults to true."
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get.json
index 90a1274ecb059..0a43f6481d86d 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get.json
@@ -57,7 +57,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_index_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_index_template.json
index 7ea6dd2944c79..fbd03f99d2547 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_index_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_index_template.json
@@ -34,7 +34,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "local":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_mapping.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_mapping.json
index 24fd668069697..321bfaba4f941 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_mapping.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_mapping.json
@@ -50,7 +50,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "local":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_settings.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_settings.json
index 68e325446d3dc..1bdaea01f87bf 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_settings.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_settings.json
@@ -58,7 +58,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_template.json
index 337016763ad0a..52aeb17913db4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.get_template.json
@@ -34,7 +34,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "local":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.open.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.open.json
index 1dab468ce4ff4..f44fb04102a7f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.open.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.open.json
@@ -28,7 +28,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
@@ -53,6 +61,14 @@
       "wait_for_active_shards":{
         "type":"string",
         "description":"Sets the number of active shards to wait for before the operation returns."
+      },
+      "wait_for_completion": {
+        "type" : "boolean",
+        "description" : "If false, the request will return a task immediately and the operation will run in background. Defaults to true."
+      },
+      "task_execution_timeout": {
+        "type" : "time",
+        "description" : "Explicit task execution timeout, only useful when wait_for_completion is false, defaults to 1h."
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_alias.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_alias.json
index 603f24b665eb7..00767afbaec04 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_alias.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_alias.json
@@ -50,7 +50,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_index_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_index_template.json
index 3f758e18737e2..a2ceb259a4376 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_index_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_index_template.json
@@ -35,7 +35,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json
index 451cbccd8d329..c8b63d4e1cee1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json
@@ -29,7 +29,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_settings.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_settings.json
index 66fe23bab8ba2..ca245ec543da3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_settings.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_settings.json
@@ -30,7 +30,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_template.json
index 75a328af929ef..3b1c230178bb8 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_template.json
@@ -34,7 +34,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.rollover.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.rollover.json
index fef1f03d1c9a7..303b7c7b03c19 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.rollover.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.rollover.json
@@ -48,7 +48,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "wait_for_active_shards":{
         "type":"string",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.shrink.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.shrink.json
index fd6d705d6a5fa..a20014a1444ec 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.shrink.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.shrink.json
@@ -35,13 +35,29 @@
         "type" : "time",
         "description" : "Explicit operation timeout"
       },
-      "master_timeout": {
-        "type" : "time",
-        "description" : "Specify timeout for connection to master"
+      "master_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "wait_for_active_shards": {
         "type" : "string",
         "description" : "Set the number of active shards to wait for on the shrunken index before the operation returns."
+      },
+      "wait_for_completion": {
+        "type" : "boolean",
+        "description" : "If false, the request will return a task immediately and the operation will run in background. Defaults to true."
+      },
+      "task_execution_timeout": {
+        "type" : "time",
+        "description" : "Explicit task execution timeout, only useful when wait_for_completion is false, defaults to 1h."
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_index_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_index_template.json
index 2b81572f0aaaf..0e42ba6028a9f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_index_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_index_template.json
@@ -34,7 +34,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_template.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_template.json
index 364547dd318a2..65b555082c3b1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_template.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.simulate_template.json
@@ -40,7 +40,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.split.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.split.json
index 02df3cdedf01f..d399bf9dbdb8a 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.split.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.split.json
@@ -35,13 +35,29 @@
         "type" : "time",
         "description" : "Explicit operation timeout"
       },
-      "master_timeout": {
-        "type" : "time",
-        "description" : "Specify timeout for connection to master"
+      "master_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "wait_for_active_shards": {
         "type" : "string",
         "description" : "Set the number of active shards to wait for on the shrunken index before the operation returns."
+      },
+      "wait_for_completion": {
+        "type" : "boolean",
+        "description" : "If false, the request will return a task immediately and the operation will run in background. Defaults to true."
+      },
+      "task_execution_timeout": {
+        "type" : "time",
+        "description" : "Explicit task execution timeout, only useful when wait_for_completion is false, defaults to 1h."
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.stats.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.stats.json
index 0a8960f2f9e89..382bb9efde0ff 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.stats.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.stats.json
@@ -118,10 +118,6 @@
         ],
         "default":"indices"
       },
-      "types":{
-        "type":"list",
-        "description":"A comma-separated list of document types for the `indexing` index metric"
-      },
       "include_segment_file_sizes":{
         "type":"boolean",
         "description":"Whether to report the aggregated disk usage of each one of the Lucene index files (only applies if segment stats are requested)",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.update_aliases.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.update_aliases.json
index d4a222f2061c8..c31cb8fe59c0f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.update_aliases.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.update_aliases.json
@@ -22,7 +22,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To promote inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.validate_query.json b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.validate_query.json
index 3becec003a9e6..cc0386ee3b972 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/indices.validate_query.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/indices.validate_query.json
@@ -26,28 +26,6 @@
               "description":"A comma-separated list of index names to restrict the operation; use `_all` or empty string to perform the operation on all indices"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/_validate/query",
-          "methods":[
-            "GET",
-            "POST"
-          ],
-          "parts":{
-            "index":{
-              "type":"list",
-              "description":"A comma-separated list of index names to restrict the operation; use `_all` or empty string to perform the operation on all indices"
-            },
-            "type":{
-              "type":"list",
-              "description":"A comma-separated list of document types to restrict the operation; leave empty to perform the operation on all types",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.delete_pipeline.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.delete_pipeline.json
index 29b4219038cd2..3e40136f556fa 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.delete_pipeline.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.delete_pipeline.json
@@ -24,7 +24,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.get_pipeline.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.get_pipeline.json
index 65fc4f91b2b42..cde980e67c8c9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.get_pipeline.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.get_pipeline.json
@@ -30,7 +30,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.put_pipeline.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.put_pipeline.json
index 4d2105866791c..5475905e7b99f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.put_pipeline.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ingest.put_pipeline.json
@@ -24,7 +24,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/put_script.json b/rest-api-spec/src/main/resources/rest-api-spec/api/put_script.json
index 750f7fdf4eb62..c8413d1476402 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/put_script.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/put_script.json
@@ -46,7 +46,15 @@
       },
       "master_timeout":{
         "type":"time",
-        "description":"Specify timeout for connection to master"
+        "description":"Specify timeout for connection to master",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Specify timeout for connection to cluster-manager node"
       },
       "context":{
         "type":"string",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.restore.json b/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.restore.json
new file mode 100644
index 0000000000000..6af49f75b9f6e
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.restore.json
@@ -0,0 +1,34 @@
+{
+  "remote_store.restore":{
+    "documentation":{
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/remote-store#restore",
+      "description":"Restores from remote store."
+    },
+    "stability":"experimental",
+    "url":{
+      "paths":[
+        {
+          "path":"/_remotestore/_restore",
+          "methods":[
+            "POST"
+          ]
+        }
+      ]
+    },
+    "params":{
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
+      },
+      "wait_for_completion":{
+        "type":"boolean",
+        "description":"Should this request wait until the operation has completed before returning",
+        "default":false
+      }
+    },
+    "body":{
+      "description":"A comma separated list of index IDs",
+      "required":true
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.stats.json b/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.stats.json
new file mode 100644
index 0000000000000..437a4439bbcb5
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/remote_store.stats.json
@@ -0,0 +1,48 @@
+{
+  "remote_store.stats":{
+    "documentation":{
+      "url": "https://opensearch.org/docs/latest/tuning-your-cluster/availability-and-recovery/remote",
+      "description":"Stats for remote store."
+    },
+    "stability":"experimental",
+    "url":{
+      "paths":[
+        {
+          "path":"/_remotestore/stats/{index}",
+          "methods":[
+            "GET"
+          ],
+          "parts":{
+            "index":{
+              "type":"string",
+              "description": "Index name to fetch stats"
+            }
+          }
+        },
+        {
+          "path":"/_remotestore/stats/{index}/{shard_id}",
+          "methods":[
+            "GET"
+          ],
+          "parts":{
+            "index":{
+              "type":"string",
+              "description":"Index name to fetch stats"
+            },
+            "shard_id":{
+              "type":"string",
+              "description":"Specific shard to fetch stats"
+            }
+          }
+        }
+      ]
+    },
+    "params":{
+      "timeout":{
+        "type":"time",
+        "default":"10s",
+        "description":"Max time each individual stats request should take."
+      }
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/search.json b/rest-api-spec/src/main/resources/rest-api-spec/api/search.json
index ac321acf8907b..e0fbeeb83ffc4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/search.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/search.json
@@ -225,6 +225,10 @@
         "type":"boolean",
         "description":"Indicates whether hits.total should be rendered as an integer or an object in the rest search response",
         "default":false
+      },
+      "search_pipeline": {
+        "type": "string",
+        "description": "The search pipeline to use to execute this request"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.delete.json b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.delete.json
new file mode 100644
index 0000000000000..1fa7060b974dc
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.delete.json
@@ -0,0 +1,35 @@
+{
+  "search_pipeline.delete": {
+    "documentation": {
+      "description": "Deletes a search pipeline.",
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/search_pipelines/"
+    },
+    "stability": "stable",
+    "url": {
+      "paths": [
+        {
+          "path": "/_search/pipeline/{id}",
+          "methods": [
+            "DELETE"
+          ],
+          "parts": {
+            "id": {
+              "type": "string",
+              "description": "Pipeline ID"
+            }
+          }
+        }
+      ]
+    },
+    "params": {
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
+      },
+      "timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout"
+      }
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.get.json b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.get.json
new file mode 100644
index 0000000000000..7cac6e7aa4bcf
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.get.json
@@ -0,0 +1,37 @@
+{
+  "search_pipeline.get": {
+    "documentation": {
+      "description": "Returns a search pipeline",
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/search_pipelines/"
+    },
+    "stability": "stable",
+    "url": {
+      "paths": [
+        {
+          "path": "/_search/pipeline",
+          "methods": [
+            "GET"
+          ]
+        },
+        {
+          "path": "/_search/pipeline/{id}",
+          "methods": [
+            "GET"
+          ],
+          "parts": {
+            "id": {
+              "type": "string",
+              "description": "Comma-separated list of search pipeline ids. Wildcards supported."
+            }
+          }
+        }
+      ]
+    },
+    "params": {
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
+      }
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.put.json b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.put.json
new file mode 100644
index 0000000000000..b7375d36825a2
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/search_pipeline.put.json
@@ -0,0 +1,39 @@
+{
+  "search_pipeline.put": {
+    "documentation": {
+      "description": "Creates or updates a search pipeline.",
+      "url": "https://opensearch.org/docs/latest/opensearch/rest-api/search_pipelines/"
+    },
+    "stability": "stable",
+    "url": {
+      "paths": [
+        {
+          "path": "/_search/pipeline/{id}",
+          "methods": [
+            "PUT"
+          ],
+          "parts": {
+            "id": {
+              "type": "string",
+              "description": "Pipeline ID"
+            }
+          }
+        }
+      ]
+    },
+    "params": {
+      "cluster_manager_timeout": {
+        "type": "time",
+        "description": "Explicit operation timeout for connection to cluster-manager node"
+      },
+      "timeout": {
+        "type": "time",
+        "description": "Explicit operation timeout"
+      }
+    },
+    "body": {
+      "description": "The search pipeline definition",
+      "required": true
+    }
+  }
+}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.cleanup_repository.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.cleanup_repository.json
index 727fe79176797..05eb3309b11e6 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.cleanup_repository.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.cleanup_repository.json
@@ -24,7 +24,15 @@
     "params": {
       "master_timeout": {
         "type" : "time",
-        "description" : "Explicit operation timeout for connection to master node"
+        "description" : "Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout": {
         "type" : "time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.clone.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.clone.json
index 18122bc209b0e..c79460fc30a48 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.clone.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.clone.json
@@ -32,7 +32,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create.json
index da8cb9916f584..64aaeaef9d897 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create.json
@@ -29,7 +29,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "wait_for_completion":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create_repository.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create_repository.json
index 431ac3c68c0bd..4965162bcd86c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create_repository.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.create_repository.json
@@ -25,7 +25,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete.json
index 30053cd5b94d3..2e21a08219942 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete.json
@@ -28,7 +28,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       }
     }
   }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete_repository.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete_repository.json
index b60aeba83a329..3fc22f969784c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete_repository.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.delete_repository.json
@@ -24,7 +24,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json
index 20006f6f499b6..e084a997a61b1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json
@@ -28,7 +28,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get_repository.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get_repository.json
index 8c91caa4fe81f..cf03bab18c03f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get_repository.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get_repository.json
@@ -30,7 +30,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "local":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.restore.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.restore.json
index 697ea395dcc2b..07148c7d261f4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.restore.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.restore.json
@@ -28,12 +28,24 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "wait_for_completion":{
         "type":"boolean",
         "description":"Should this request wait until the operation has completed before returning",
         "default":false
+      },
+      "source_remote_store_repository": {
+        "type":"string",
+        "description":"Remote Store Repository of Remote Store Indices"
       }
     },
     "body":{
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.status.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.status.json
index 70a7ba23ef506..4f22c24fd9a56 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.status.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.status.json
@@ -46,7 +46,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "ignore_unavailable":{
         "type":"boolean",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.verify_repository.json b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.verify_repository.json
index de638c19d4a0b..865eb15d11310 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.verify_repository.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.verify_repository.json
@@ -24,7 +24,15 @@
     "params":{
       "master_timeout":{
         "type":"time",
-        "description":"Explicit operation timeout for connection to master node"
+        "description":"Explicit operation timeout for connection to master node",
+        "deprecated":{
+          "version":"2.0.0",
+          "description":"To support inclusive language, use 'cluster_manager_timeout' instead."
+        }
+      },
+      "cluster_manager_timeout":{
+        "type":"time",
+        "description":"Explicit operation timeout for connection to cluster-manager node"
       },
       "timeout":{
         "type":"time",
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/update.json b/rest-api-spec/src/main/resources/rest-api-spec/api/update.json
index 81bc101600aeb..c8d1ed435756b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/update.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/update.json
@@ -22,31 +22,6 @@
               "description":"The name of the index"
             }
           }
-        },
-        {
-          "path":"/{index}/{type}/{id}/_update",
-          "methods":[
-            "POST"
-          ],
-          "parts":{
-            "id":{
-              "type":"string",
-              "description":"Document ID"
-            },
-            "index":{
-              "type":"string",
-              "description":"The name of the index"
-            },
-            "type":{
-              "type":"string",
-              "description":"The type of the document",
-              "deprecated":true
-            }
-          },
-          "deprecated":{
-            "version":"7.0.0",
-            "description":"Specifying types in urls has been deprecated"
-          }
         }
       ]
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/10_basic.yml
index 8c8c6d50abf41..c91ec511a0fdb 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/10_basic.yml
@@ -223,4 +223,3 @@
   - match: { items.0.index.status: 400 }
   - match: { items.0.index.error.type: illegal_argument_exception }
   - match: { items.0.index.error.reason: "no write index is defined for alias [test_index]. The write index may be explicitly disabled using is_write_index=false or the alias points to multiple indices without one being designated as a write index" }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/20_list_of_strings.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/20_list_of_strings.yml
index 3d956dce54289..cb3553abbd435 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/20_list_of_strings.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/20_list_of_strings.yml
@@ -14,4 +14,3 @@
         index: test_index
 
   - match: {count: 2}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/30_big_string.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/30_big_string.yml
index 8b6467eeed975..fabe674697cde 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/30_big_string.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/30_big_string.yml
@@ -14,4 +14,3 @@
         index: test_index
 
   - match: {count: 2}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/40_source.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/40_source.yml
index e29e84740ee5c..fb9554619a818 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/40_source.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/40_source.yml
@@ -68,4 +68,3 @@
 
   - match: { items.0.update.get._source.foo: garply }
   - is_false: items.0.update.get._source.bar
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/60_deprecated.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/60_deprecated.yml
deleted file mode 100644
index 8c8a840eb3f47..0000000000000
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/bulk/60_deprecated.yml
+++ /dev/null
@@ -1,20 +0,0 @@
-
----
-"Deprecated parameters should fail in Bulk query":
-   - do:
-       catch:  bad_request
-       bulk:
-           body: |
-               { "update": { "_index": "test_index", "_type": "test_type", "_id": "test_id_1", "_version": 1 } }
-               { "doc": { "f1": "v1" } }
-               { "update": { "_index": "test_index", "_type": "test_type", "_id": "test_id_2", "_version": 1 } }
-               { "doc": { "f1": "v2" } }
-
-   - do:
-       catch:  bad_request
-       bulk:
-           body: |
-               { "update": { "_index": "test_index", "_type": "test_type", "_id": "test_id_1", "_routing": "test1" } }
-               { "doc": { "f1": "v1" } }
-               { "update": { "_index": "test_index", "_type": "test_type", "_id": "test_id_2", "_routing": "test1" } }
-               { "doc": { "f1": "v2" } }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.cluster_manager/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.cluster_manager/10_basic.yml
index b0f1c81b56a0e..6354c751aa5f3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.cluster_manager/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.cluster_manager/10_basic.yml
@@ -20,7 +20,7 @@ setup:
             host     .+ \n
             ip       .+ \n
             node     .+ \n
-        
+
         $/
 
 ---
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.health/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.health/10_basic.yml
index 0d945d01a6ddb..52b27837a61ac 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.health/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.health/10_basic.yml
@@ -9,9 +9,9 @@
         help: true
       node_selector:
         # Only send request to nodes in <2.0 versions, especially during ':qa:mixed-cluster:v1.x.x#mixedClusterTest'.
-        # Because YAML REST test takes the minimum OpenSearch version in the cluster to apply the filter in 'skip' section, 
+        # Because YAML REST test takes the minimum OpenSearch version in the cluster to apply the filter in 'skip' section,
         # see OpenSearchClientYamlSuiteTestCase#initAndResetContext() for detail.
-        # During 'mixedClusterTest', the cluster can be mixed with nodes in 1.x and 2.x versions, 
+        # During 'mixedClusterTest', the cluster can be mixed with nodes in 1.x and 2.x versions,
         # so node_selector is required, and only filtering version in 'skip' is not enough.
         version: "1.0.0 - 1.4.99"
 
@@ -61,7 +61,7 @@
                    pending_tasks .+ \n
                    max_task_wait_time .+ \n
                    active_shards_percent .+ \n
-      
+
                $/
 
 ---
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.nodes/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.nodes/10_basic.yml
index 789ea5fc19c3f..525d705de88f1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.nodes/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.nodes/10_basic.yml
@@ -10,9 +10,9 @@
         v: true
       node_selector:
         # Only send request to nodes in <2.0 versions, especially during ':qa:mixed-cluster:v1.x.x#mixedClusterTest'.
-        # Because YAML REST test takes the minimum OpenSearch version in the cluster to apply the filter in 'skip' section, 
+        # Because YAML REST test takes the minimum OpenSearch version in the cluster to apply the filter in 'skip' section,
         # see OpenSearchClientYamlSuiteTestCase#initAndResetContext() for detail.
-        # During 'mixedClusterTest', the cluster can be mixed with nodes in 1.x and 2.x versions, 
+        # During 'mixedClusterTest', the cluster can be mixed with nodes in 1.x and 2.x versions,
         # so node_selector is required, and only filtering version in 'skip' is not enough.
         version: "1.0.0 - 1.4.99"
 
@@ -32,8 +32,8 @@
 
   - match:
       $body: |
-        /  #ip                          heap.percent        ram.percent     cpu         load_1m                load_5m                load_15m               node.role                   cluster_manager       name
-        ^  ((\d{1,3}\.){3}\d{1,3}  \s+  \d+            \s+  \d*         \s+ (-)?\d* \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)?\s+  ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) \s+ [-*x]            \s+  (\S+\s?)+     \n)+  $/
+        /  #ip                          heap.percent        ram.percent     cpu         load_1m                load_5m                load_15m               node.role               node.roles                   cluster_manager       name
+        ^  ((\d{1,3}\.){3}\d{1,3}  \s+  \d+            \s+  \d*         \s+ (-)?\d* \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)?\s+  ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) (\s+ (-|\w+(,\w+)*+))? \s+ [-*x]            \s+  (\S+\s?)+     \n)+  $/
 
   - do:
       cat.nodes:
@@ -41,8 +41,8 @@
 
   - match:
       $body: |
-        /^  ip                     \s+  heap\.percent   \s+  ram\.percent \s+ cpu      \s+ load_1m            \s+ load_5m            \s+ load_15m           \s+ node\.role              \s+  cluster_manager   \s+   name  \n
-           ((\d{1,3}\.){3}\d{1,3}  \s+  \d+             \s+  \d*          \s+ (-)?\d* \s+  ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) \s+  [-*x]             \s+   (\S+\s?)+     \n)+  $/
+        /^  ip                     \s+  heap\.percent   \s+  ram\.percent \s+ cpu      \s+ load_1m            \s+ load_5m            \s+ load_15m           \s+ node\.role           (\s+ node\.roles)?              \s+  cluster_manager   \s+   name  \n
+           ((\d{1,3}\.){3}\d{1,3}  \s+  \d+             \s+  \d*          \s+ (-)?\d* \s+  ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ ((-)?\d*(\.\d+)?)? \s+ (-|[cdhilmrstvw]{1,11}) (\s+ (-|\w+(,\w+)*+ ))? \s+ [-*x]             \s+   (\S+\s?)+     \n)+  $/
 
   - do:
       cat.nodes:
@@ -131,4 +131,3 @@
   - match:
       $body: |
                /^(\S{5,}\n)+$/
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.shards/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.shards/10_basic.yml
index aa4abc7a11eae..f80c9f9c0bc80 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.shards/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.shards/10_basic.yml
@@ -1,11 +1,13 @@
----
 "Help":
   - skip:
-      version: " - 7.99.99"
-      reason:  shard path stats were added in 8.0.0
+      version: " - 2.3.99"
+      reason:  point in time stats were added in 2.4.0
+      features: node_selector
   - do:
       cat.shards:
         help: true
+      node_selector:
+        version: "2.4.0 - "
 
   - match:
       $body: |
@@ -67,6 +69,9 @@
                     search.scroll_current            .+   \n
                     search.scroll_time               .+   \n
                     search.scroll_total              .+   \n
+                    search.point_in_time_current     .+   \n
+                    search.point_in_time_time        .+   \n
+                    search.point_in_time_total       .+   \n
                     segments.count                   .+   \n
                     segments.memory                  .+   \n
                     segments.index_writer_memory     .+   \n
@@ -82,6 +87,92 @@
                     path.state                       .+   \n
                $/
 ---
+"Help before - 2.4.0":
+  - skip:
+      version: "2.4.0 - "
+      reason:  point in time stats were added in 2.4.0
+      features: node_selector
+  - do:
+      cat.shards:
+        help: true
+      node_selector:
+        version: " - 2.3.99"
+
+  - match:
+      $body: |
+        /^   index                            .+   \n
+             shard                            .+   \n
+             prirep                           .+   \n
+             state                            .+   \n
+             docs                             .+   \n
+             store                            .+   \n
+             ip                               .+   \n
+             id                               .+   \n
+             node                             .+   \n
+             sync_id                          .+   \n
+             unassigned.reason                .+   \n
+             unassigned.at                    .+   \n
+             unassigned.for                   .+   \n
+             unassigned.details               .+   \n
+             recoverysource.type              .+   \n
+             completion.size                  .+   \n
+             fielddata.memory_size            .+   \n
+             fielddata.evictions              .+   \n
+             query_cache.memory_size          .+   \n
+             query_cache.evictions            .+   \n
+             flush.total                      .+   \n
+             flush.total_time                 .+   \n
+             get.current                      .+   \n
+             get.time                         .+   \n
+             get.total                        .+   \n
+             get.exists_time                  .+   \n
+             get.exists_total                 .+   \n
+             get.missing_time                 .+   \n
+             get.missing_total                .+   \n
+             indexing.delete_current          .+   \n
+             indexing.delete_time             .+   \n
+             indexing.delete_total            .+   \n
+             indexing.index_current           .+   \n
+             indexing.index_time              .+   \n
+             indexing.index_total             .+   \n
+             indexing.index_failed            .+   \n
+             merges.current                   .+   \n
+             merges.current_docs              .+   \n
+             merges.current_size              .+   \n
+             merges.total                     .+   \n
+             merges.total_docs                .+   \n
+             merges.total_size                .+   \n
+             merges.total_time                .+   \n
+             refresh.total                    .+   \n
+             refresh.time                     .+   \n
+             refresh.external_total           .+   \n
+             refresh.external_time            .+   \n
+             refresh.listeners                .+   \n
+             search.fetch_current             .+   \n
+             search.fetch_time                .+   \n
+             search.fetch_total               .+   \n
+             search.open_contexts             .+   \n
+             search.query_current             .+   \n
+             search.query_time                .+   \n
+             search.query_total               .+   \n
+             search.scroll_current            .+   \n
+             search.scroll_time               .+   \n
+             search.scroll_total              .+   \n
+             segments.count                   .+   \n
+             segments.memory                  .+   \n
+             segments.index_writer_memory     .+   \n
+             segments.version_map_memory      .+   \n
+             segments.fixed_bitset_memory     .+   \n
+             seq_no.max                       .+   \n
+             seq_no.local_checkpoint          .+   \n
+             seq_no.global_checkpoint         .+   \n
+             warmer.current                   .+   \n
+             warmer.total                     .+   \n
+             warmer.total_time                .+   \n
+             path.data                        .+   \n
+             path.state                       .+   \n
+        $/
+---
 "Test cat shards output":
 
   - do:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.thread_pool/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.thread_pool/10_basic.yml
index 1ce8468cb51f9..00ec838489f63 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cat.thread_pool/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cat.thread_pool/10_basic.yml
@@ -1,3 +1,29 @@
+"Test cat thread_pool total_wait_time output":
+  - skip:
+      version: " - 2.10.99"
+      reason: thread_pool total_wait_time stats were introduced in V_2.11.0
+
+  - do:
+      cat.thread_pool: {}
+
+  - match:
+      $body: |
+        /  #node_name     name     active     queue     rejected
+        ^  (\S+       \s+ \S+  \s+ \d+    \s+ \d+   \s+ \d+      \n)+  $/
+
+  - do:
+      cat.thread_pool:
+        thread_pool_patterns: search,search_throttled,index_searcher,generic
+        h: name,total_wait_time,twt
+        v: true
+
+  - match:
+      $body: |
+        /^  name              \s+ total_wait_time \s+ twt              \n
+           (generic           \s+ -1              \s+ -1               \n
+            search            \s+ \d*\.*\d*\D+    \s+ \d*\.*\d*\D+     \n
+            search_throttled  \s+ \d*\.*\d*\D+    \s+ \d*\.*\d*\D+     \n)+  $/
+
 ---
 "Test cat thread_pool output":
   - skip:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.pending_tasks/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.pending_tasks/10_basic.yml
index f8fd8ebef170d..885f6c4a97912 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.pending_tasks/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.pending_tasks/10_basic.yml
@@ -11,4 +11,3 @@
         local: true
 
   - is_true: tasks
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.put_settings/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.put_settings/10_basic.yml
index 825bac9f91649..60081783bb346 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.put_settings/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.put_settings/10_basic.yml
@@ -69,3 +69,36 @@
         include_defaults: true
 
  - match: {defaults.node.attr.testattr: "test"}
+
+---
+"Test set search backpressure mode":
+
+  - skip:
+      version: "- 2.3.99"
+      reason: "Search backpressure was added in 2.4"
+
+  - do:
+      cluster.put_settings:
+        body:
+          persistent:
+            search_backpressure.mode: "monitor_only"
+
+  - match: {persistent: {search_backpressure: {mode: "monitor_only"}}}
+
+---
+"Test set invalid search backpressure mode":
+
+  - skip:
+      version: "- 2.7.99"
+      reason: "Parsing and validation of SearchBackpressureMode does not exist in versions < 2.8"
+
+  - do:
+      catch: bad_request
+      cluster.put_settings:
+        body:
+          persistent:
+            search_backpressure.mode: "monitor-only"
+
+  - match: {error.root_cause.0.type: "illegal_argument_exception"}
+  - match: { error.root_cause.0.reason: "Invalid SearchBackpressureMode: monitor-only" }
+  - match: { status: 400 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.remote_info/10_info.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.remote_info/10_info.yml
index e11eff2b78a3c..75058cefd5c53 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.remote_info/10_info.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.remote_info/10_info.yml
@@ -3,4 +3,3 @@
   - do:
       cluster.remote_info: {}
   - is_true: ''
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/10_basic.yml
index fa973454cfba5..294f00bdd822b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/10_basic.yml
@@ -17,18 +17,18 @@
 
   - is_true: cluster_uuid
   - is_true: master_node
-    
+
 ---
 "Get cluster state returns cluster_manager_node":
   - skip:
       version: " - 1.4.99"
       reason: "The metric cluster_manager_node is added to cluster state in version 2.0.0"
-      
+
   - do:
       cluster.state: {}
-      
+
   - set:
       cluster_manager_node: node_id
-      
+
   - match: {master_node: $node_id}
   - match: {cluster_manager_node: $node_id}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/20_filtering.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/20_filtering.yml
index 3d20f1d0f7e52..b17201a911290 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/20_filtering.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/20_filtering.yml
@@ -169,7 +169,7 @@ setup:
       cluster.state:
         metric: [ master_node, version ]
       allowed_warnings:
-        - 'Deprecated value [master_node] used for parameter [metric]. To promote inclusive language, please use [cluster_manager_node] instead. It will be unsupported in a future major version.'
+        - 'Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.'
 
   - match: { cluster_uuid: $cluster_uuid }
   - is_true: master_node
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.voting_config_exclusions/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.voting_config_exclusions/10_basic.yml
index 5474c9bdf4da0..23eebacabf3f3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.voting_config_exclusions/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/cluster.voting_config_exclusions/10_basic.yml
@@ -104,4 +104,3 @@ teardown:
       cluster.post_voting_config_exclusions:
         node_ids: nodeId
         node_names: nodeName
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/create/40_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/create/40_routing.yml
index 9c048c361bd5c..e1341ac2b5380 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/create/40_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/create/40_routing.yml
@@ -39,4 +39,3 @@
       get:
           index:   test_1
           id:      1
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/delete/30_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/delete/30_routing.yml
index 27e9350caed70..c3c407cd9173a 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/delete/30_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/delete/30_routing.yml
@@ -30,4 +30,3 @@
           index:   test_1
           id:      1
           routing: 5
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/get/15_default_values.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/get/15_default_values.yml
index 921397b238f51..fabf8fb87a7b6 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/get/15_default_values.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/get/15_default_values.yml
@@ -14,4 +14,3 @@
   - match: { _index:   test_1 }
   - match: { _id:      '1'    }
   - match: { _source:  { foo: "bar" } }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/get/20_stored_fields.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/get/20_stored_fields.yml
index 23c7e5cbc90a6..1bafdc3dab21f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/get/20_stored_fields.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/get/20_stored_fields.yml
@@ -48,5 +48,3 @@
   - match: { fields.foo:  [bar] }
   - match: { fields.count:  [1] }
   - match: { _source.foo: bar }
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/get/40_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/get/40_routing.yml
index 9ba546d6ef942..7f45b39add8a7 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/get/40_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/get/40_routing.yml
@@ -41,4 +41,3 @@
       get:
           index:   test_1
           id:      1
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/get/90_versions.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/get/90_versions.yml
index 9037a9113e937..3f45a1da09dce 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/get/90_versions.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/get/90_versions.yml
@@ -80,4 +80,3 @@
           id:     1
           version: 1
           version_type: external_gte
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/100_partial_flat_object.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/100_partial_flat_object.yml
new file mode 100644
index 0000000000000..91e4127da9c32
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/100_partial_flat_object.yml
@@ -0,0 +1,606 @@
+---
+# The test setup includes:
+# - Create flat_object mapping for test_partial_flat_object index
+# - Index two example documents
+# - Refresh the index so it is ready for search tests
+
+setup:
+  - do:
+      indices.create:
+        index: test_partial_flat_object
+        body:
+          mappings:
+            properties:
+              issue:
+                properties:
+                  number:
+                    type: "integer"
+                  labels:
+                    type: "flat_object"
+  - do:
+      index:
+        index: test_partial_flat_object
+        id: 1
+        body: {
+          "issue": {
+            "number": 123,
+            "labels": {
+              "version": "2.2",
+              "backport": [
+                "2.0",
+                "1.9"
+              ],
+              "category": {
+                "type": "API",
+                "level": "bug"
+              },
+              "createdDate": "2023-01-01",
+              "comment": [ [ "Doe","Shipped" ],[ "John","Approved" ] ],
+              "views": 288,
+              "priority": 5.00
+            }
+          }
+        }
+
+  - do:
+      index:
+        index: test_partial_flat_object
+        id: 2
+        body: {
+          "issue": {
+            "number": 456,
+            "labels": {
+              "author": "Liu",
+              "version": "2.1",
+              "backport": [
+                "2.0",
+                "1.3"
+              ],
+              "category": {
+                "type": "API",
+                "level": "enhancement"
+              },
+              "createdDate": "2023-02-01",
+              "comment": [ [ "Mike","LGTM" ],[ "John","Approved" ] ],
+              "views": 3333,
+              "priority": 1.50
+            }
+          }
+        }
+
+  - do:
+      index:
+        index: test_partial_flat_object
+        id: 3
+        body: {
+          "issue": {
+            "number": 999,
+            "labels": [ {
+              "version": "1.1",
+              "backport": [
+                "1.0",
+                "0.9"
+              ],
+              "category": {
+                "type": "Module",
+                "level": "feature"
+              }
+            } ]
+          }
+        }
+
+  - do:
+      indices.refresh:
+        index: test_partial_flat_object
+---
+# Delete Index when connection is teardown
+teardown:
+  - do:
+      indices.delete:
+        index: test_partial_flat_object
+
+
+---
+# Verify that mappings under the catalog field did not expand
+# and no dynamic fields were created.
+"Mappings":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+  - do:
+      indices.get_mapping:
+        index: test_partial_flat_object
+  - is_true: test_partial_flat_object.mappings
+  - match: { test_partial_flat_object.mappings.properties.issue.properties.number.type: integer }
+  - match: { test_partial_flat_object.mappings.properties.issue.properties.labels.type: flat_object }
+  # https://github.com/opensearch-project/OpenSearch/tree/main/rest-api-spec/src/main/resources/rest-api-spec/test#length
+  - length: { test_partial_flat_object.mappings.properties.issue.properties: 2 }
+  - length: { test_partial_flat_object.mappings.properties.issue.properties.labels: 1 }
+
+
+---
+"Supported queries":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+
+  # Verify Document Count
+  - do:
+      search:
+        body: {
+          query: {
+            match_all: { }
+          }
+        }
+
+  - length: { hits.hits: 3 }
+
+  # Match Query with exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            match: { "issue.labels.version": "2.1" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.version: "2.1" }
+
+  # Match Query without exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            match: { issue.labels: "2.1" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.version: "2.1" }
+
+  # Multi Match Query with exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            multi_match: {
+              "query": "2.0",
+              "fields": [ "issue.labels.version", "issue.labels.backport" ]
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.backport: [ "2.0", "1.9" ] }
+  - match: { hits.hits.1._source.issue.labels.backport: [ "2.0", "1.3" ] }
+
+  # Term Query1 with exact dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels.createdDate: "2023-01-01" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.createdDate: "2023-01-01" }
+
+  # Term Query1 without exact dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels: "2023-01-01" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.createdDate: "2023-01-01" }
+
+
+  # Term Query2 with dot path for string
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { "issue.labels.category.type": "API" }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.category.type: "API" }
+  - match: { hits.hits.1._source.issue.labels.category.type: "API" }
+
+  # Term Query2 without exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels: "API" }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.category.type: "API" }
+  - match: { hits.hits.1._source.issue.labels.category.type: "API" }
+
+  # Term Query3 with dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels.backport: "1.9" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.backport: [ "2.0", "1.9" ] }
+
+  # Term Query3 without dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels: "1.9" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.backport: [ "2.0", "1.9" ] }
+
+  # Term Query4 with  dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels.comment: "LGTM" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Term Query4 without dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels: "LGTM" }
+          }
+        }
+
+  # Term Query5 with  dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels.category.type: "Module" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.0.category.type: "Module" }
+
+  # Term Query5 without dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels: "Module" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.0.category.type: "Module" }
+
+  # Terms Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            terms: { issue.labels: [ "John","Mike" ] }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Terms Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            terms: { issue.labels.comment: [ "John","Mike" ] }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Prefix Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "prefix": {
+              "issue.labels.comment": {
+                "value": "Mi"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Prefix Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "prefix": {
+              "issue.labels": {
+                "value": "Mi"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Range Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels.version": {
+                "gte": "2.1",
+                "lte": "3.0"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.version: "2.2" }
+  - match: { hits.hits.1._source.issue.labels.version: "2.1" }
+
+  # Range Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels": {
+                "gte": "2.1",
+                "lte": "3.0"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.version: "2.2" }
+  - match: { hits.hits.1._source.issue.labels.version: "2.1" }
+
+  # Range Query with integer input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels.views": {
+                "gte": 3000,
+                "lte": 4000
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.views: 3333 }
+
+  # Range Query with integer input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels": {
+                "gte": 3000,
+                "lte": 4000
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.views: 3333 }
+
+
+  # Range Query with double input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels.priority": {
+                "gte": 4.1234,
+                "lte": 5.1234
+              }
+            }
+          }
+        }
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.priority: 5.00 }
+
+  # Range Query with double input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "issue.labels": {
+                "gte": 4.1234,
+                "lte": 5.1234
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.priority: 5.00 }
+
+
+  # Exists Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": issue.labels.priority
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Exists Query with nested dot path, use the flat_object_field_name.last_key
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": issue.labels.type
+            }
+          }
+        }
+
+  - length: { hits.hits: 3 }
+
+  # Exists Query without dot path for the flat_object_field_name
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": issue.labels
+            }
+          }
+        }
+
+  - length: { hits.hits: 3 }
+
+  # Exists Query2 with dot path for one hit
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": issue.labels.author
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+
+  # Query_string Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "query_string": {
+              "fields": [ "issue.labels" ],
+              "query": "Doe OR Mike"
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "query_string": {
+              "fields": [ "issue.labels.comment" ],
+              "query": "Doe OR Mike"
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Simple_query_string Query without full dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "simple_query_string": {
+              "query": "Doe",
+              "fields": [ "issue.labels" ]
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+
+  # Simple_query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "simple_query_string": {
+              "query": "Doe",
+              "fields": [ "issue.labels.comment" ]
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/105_partial_flat_object_nested.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/105_partial_flat_object_nested.yml
new file mode 100644
index 0000000000000..ce172c2773e1f
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/105_partial_flat_object_nested.yml
@@ -0,0 +1,636 @@
+---
+# The test setup includes:
+# - Create flat_object mapping for test_partial_flat_object_nested index
+# - Index two example documents
+# - Refresh the index so it is ready for search tests
+
+setup:
+  - do:
+      indices.create:
+        index: test_partial_flat_object_nested
+        body:
+          mappings:
+            properties:
+              issue:
+                type: "nested"
+                properties:
+                  number:
+                    type: "integer"
+                  labels:
+                    type: "flat_object"
+  - do:
+      index:
+        index: test_partial_flat_object_nested
+        id: 1
+        body: {
+          "issue": [
+            {
+              "number": 123,
+              "labels": {
+                "version": "2.2",
+                "backport": [
+                  "2.0",
+                  "1.9"
+                ],
+                "category": {
+                  "type": "API",
+                  "level": "bug"
+                },
+                "createdDate": "2023-01-01",
+                "comment": [ [ "Doe","Shipped" ],[ "John","Approved" ] ],
+                "views": 288,
+                "priority": 5.00
+              }
+            }
+          ]
+        }
+
+  - do:
+      index:
+        index: test_partial_flat_object_nested
+        id: 2
+        body: {
+          "issue": [
+            {
+              "number": 456,
+              "labels": {
+                "author": "Liu",
+                "version": "2.1",
+                "backport": [
+                  "2.0",
+                  "1.3"
+                ],
+                "category": {
+                  "type": "API",
+                  "level": "enhancement"
+                },
+                "createdDate": "2023-02-01",
+                "comment": [ [ "Mike","LGTM" ],[ "John","Approved" ] ],
+                "views": 3333,
+                "priority": 1.50
+              }
+            }
+          ]
+        }
+
+  - do:
+      indices.refresh:
+        index: test_partial_flat_object_nested
+---
+# Delete Index when connection is teardown
+teardown:
+  - do:
+      indices.delete:
+        index: test_partial_flat_object_nested
+
+
+---
+# Verify that mappings under the catalog field did not expand
+# and no dynamic fields were created.
+"Mappings":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+  - do:
+      indices.get_mapping:
+        index: test_partial_flat_object_nested
+  - is_true: test_partial_flat_object_nested.mappings
+  - match: { test_partial_flat_object_nested.mappings.properties.issue.properties.number.type: integer }
+  - match: { test_partial_flat_object_nested.mappings.properties.issue.properties.labels.type: flat_object }
+  # https://github.com/opensearch-project/OpenSearch/tree/main/rest-api-spec/src/main/resources/rest-api-spec/test#length
+  - length: { test_partial_flat_object_nested.mappings.properties.issue.properties: 2 }
+  - length: { test_partial_flat_object_nested.mappings.properties.issue.properties.labels: 1 }
+
+
+---
+"Supported queries":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+
+  # Verify Document Count
+  - do:
+      search:
+        body: {
+          query: {
+            match_all: { }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Match Query with exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                match: { "issue.labels.version": "2.1" }
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.version: "2.1" }
+
+  # Match Query without exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                match: { "issue.labels": "2.1" }
+              }
+            }
+          }
+        }
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.version: "2.1" }
+
+  # Term Query1 with exact dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels.createdDate: "2023-01-01" }
+              }
+            } } }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.createdDate: "2023-01-01" }
+
+  # Term Query1 without exact dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels: "2023-01-01" }
+              } } }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.createdDate: "2023-01-01" }
+
+  # Term Query2 with dot path for string
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { "issue.labels.category.type": "API" }
+              } } }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.category.type: "API" }
+  - match: { hits.hits.1._source.issue.0.labels.category.type: "API" }
+
+  # Term Query2 without exact dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels: "API" }
+              } } }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.category.type: "API" }
+  - match: { hits.hits.1._source.issue.0.labels.category.type: "API" }
+
+  # Term Query3 with dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels.backport: "1.9" }
+              } } }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.backport: [ "2.0", "1.9" ] }
+
+  # Term Query3 without dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels: "1.9" }
+              } } }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.backport: [ "2.0", "1.9" ] }
+
+  # Term Query4 with  dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels.comment: "LGTM" }
+              } } }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Term Query4 without dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                term: { issue.labels: "LGTM" } } }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Terms Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                terms: { issue.labels: [ "John","Mike" ] } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Terms Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                terms: { issue.labels.comment: [ "John","Mike" ] } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Prefix Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "prefix": {
+                  "issue.labels.comment": {
+                    "value": "Mi"
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Prefix Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "prefix": {
+                  "issue.labels": {
+                    "value": "Mi"
+                  }
+                }
+              } } }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Range Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels.version": {
+                    "gte": "2.1",
+                    "lte": "3.0"
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.version: "2.2" }
+  - match: { hits.hits.1._source.issue.0.labels.version: "2.1" }
+
+  # Range Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels": {
+                    "gte": "2.1",
+                    "lte": "3.0"
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.version: "2.2" }
+  - match: { hits.hits.1._source.issue.0.labels.version: "2.1" }
+
+  # Range Query with integer input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels.views": {
+                    "gte": 3000,
+                    "lte": 4000
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.views: 3333 }
+
+  # Range Query with integer input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels": {
+                    "gte": 3000,
+                    "lte": 4000
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.views: 3333 }
+
+
+  # Range Query with double input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels.priority": {
+                    "gte": 4.1234,
+                    "lte": 5.1234
+                  } } }
+            }
+          }
+        }
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.priority: 5.00 }
+
+  # Range Query with double input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "range": {
+                  "issue.labels": {
+                    "gte": 4.1234,
+                    "lte": 5.1234
+                  } } }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.priority: 5.00 }
+
+
+  # Exists Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "exists": {
+                  "field": issue.labels.priority
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Exists Query with nested dot path, use the flat_object_field_name.last_key
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "exists": {
+                  "field": issue.labels.type
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Exists Query without dot path for the flat_object_field_name
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "exists": {
+                  "field": issue.labels
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Exists Query2 with dot path for one hit
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "exists": {
+                  "field": issue.labels.author
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+
+  # Query_string Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "query_string": {
+                  "fields": [ "issue.labels" ],
+                  "query": "Doe OR Mike"
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "query_string": {
+                  "fields": [ "issue.labels.comment" ],
+                  "query": "Doe OR Mike"
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+  - match: { hits.hits.1._source.issue.0.labels.comment: [ [ "Mike","LGTM" ],[ "John","Approved" ] ] }
+
+  # Simple_query_string Query without full dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "simple_query_string": {
+                  "query": "Doe",
+                  "fields": [ "issue.labels" ]
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
+
+  # Simple_query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            nested: {
+              path: "issue",
+              query: {
+                "simple_query_string": {
+                  "query": "Doe",
+                  "fields": [ "issue.labels.comment" ]
+                } } }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.0.labels.comment: [ [ "Doe","Shipped" ],[ "John","Approved" ] ] }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/40_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/40_routing.yml
index 630cf39dbe65c..f6f497269b043 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/index/40_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/40_routing.yml
@@ -40,4 +40,3 @@
       get:
           index:   test_1
           id:      1
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/80_geo_point.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/80_geo_point.yml
new file mode 100644
index 0000000000000..7d6c2b835f1f7
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/80_geo_point.yml
@@ -0,0 +1,151 @@
+setup:
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          settings:
+            number_of_replicas: 0
+          mappings:
+            properties:
+              location:
+                type: geo_point
+
+---
+"Single point test":
+  - skip:
+      version: " - 2.3.99"
+      reason: "geojson format is supported in 2.4 and above"
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+              _id: 1
+          - location:
+              lon: 52.374081
+              lat: 4.912350
+          - index:
+              _index: test_1
+              _id: 2
+          - location: "4.901618,52.369219"
+          - index:
+              _index: test_1
+              _id: 3
+          - location: [ 52.371667, 4.914722 ]
+          - index:
+              _index: test_1
+              _id: 4
+          - location: "POINT (52.371667 4.914722)"
+          - index:
+              _index: test_1
+              _id: 5
+          - location: "t0v5zsq1gpzf"
+          - index:
+              _index: test_1
+              _id: 6
+          - location:
+              type: Point
+              coordinates: [ 52.371667, 4.914722 ]
+
+  - do:
+      search:
+        index: test_1
+        rest_total_hits_as_int: true
+        body:
+          query:
+            geo_shape:
+              location:
+                shape:
+                  type: "envelope"
+                  coordinates: [ [ 51, 5 ], [ 53, 3 ] ]
+
+  - match: { hits.total: 6 }
+
+  - do:
+      search:
+        index: test_1
+        rest_total_hits_as_int: true
+        body:
+          query:
+            geo_shape:
+              location:
+                shape:
+                  type: "envelope"
+                  coordinates: [ [ 151, 15 ], [ 153, 13 ] ]
+
+  - match: { hits.total: 0 }
+
+---
+"Multi points test":
+  - skip:
+      version: " - 2.3.99"
+      reason: "geojson format is supported in 2.4 and above"
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+              _id: 1
+          - location:
+              - {lon: 52.374081, lat: 4.912350}
+              - {lon: 152.374081, lat: 14.912350}
+          - index:
+              _index: test_1
+              _id: 2
+          - location:
+              - "4.901618,52.369219"
+              - "14.901618,152.369219"
+          - index:
+              _index: test_1
+              _id: 3
+          - location:
+              - [ 52.371667, 4.914722 ]
+              - [ 152.371667, 14.914722 ]
+          - index:
+              _index: test_1
+              _id: 4
+          - location:
+              - "POINT (52.371667 4.914722)"
+              - "POINT (152.371667 14.914722)"
+          - index:
+              _index: test_1
+              _id: 5
+          - location:
+              - "t0v5zsq1gpzf"
+              - "x6skg0zbhnum"
+          - index:
+              _index: test_1
+              _id: 6
+          - location:
+              - {type: Point, coordinates: [ 52.371667, 4.914722 ]}
+              - {type: Point, coordinates: [ 152.371667, 14.914722 ]}
+
+  - do:
+      search:
+        index: test_1
+        rest_total_hits_as_int: true
+        body:
+          query:
+            geo_shape:
+              location:
+                shape:
+                  type: "envelope"
+                  coordinates: [ [ 51, 5 ], [ 53, 3 ] ]
+
+  - match: { hits.total: 6 }
+
+  - do:
+      search:
+        index: test_1
+        rest_total_hits_as_int: true
+        body:
+          query:
+            geo_shape:
+              location:
+                shape:
+                  type: "envelope"
+                  coordinates: [ [ 151, 15 ], [ 153, 13 ] ]
+
+  - match: { hits.total: 6 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_flat_object.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_flat_object.yml
new file mode 100644
index 0000000000000..0a5f7444efd17
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_flat_object.yml
@@ -0,0 +1,746 @@
+---
+# The initial test setup includes:
+# - Create flat_object mapping
+# - Index two example documents
+# - Refresh the index so it is ready for search tests
+setup:
+  - do:
+      indices.create:
+        index: test
+        body:
+          mappings:
+            properties:
+              ISBN13:
+                type : "keyword"
+              catalog:
+                type : "flat_object"
+              required_matches:
+                type : "long"
+
+  - do:
+      index:
+        index: test
+        id:    1
+        body:  {
+          "ISBN13": "V9781933988177",
+          "catalog": {
+            "title": "Lucene in Action",
+            "author":
+              {
+                "surname": "McCandless",
+                "given": "Mike"
+              },
+            "catalogId":"c-0002",
+            "quantity": 1234,
+            "rating": 9.2,
+            "location": [-81.7982,41.3847 ],
+            "review": [["great",99.8],["ok",80.0]],
+            "publishDate": "2015-01-01"
+          },
+          "required_matches": 1
+        }
+
+  - do:
+      index:
+        index: test
+        id: 2
+        body: {
+          "ISBN13": "V12154942129175",
+          "catalog": {
+            "title": "Mock in Action",
+            "author":
+              {
+                "surname": "Doe",
+                "given": "John"
+              },
+            "catalogId": "c-0050",
+            "quantity": 4321,
+            "rating": 5.2,
+            "location": [-12.7982,33.3847 ],
+            "review": [["bad",30.41],["ok",80.0]],
+            "publishDate": "2016-01-01"
+          },
+          "required_matches": 1
+        }
+
+  # Do index refresh
+  - do:
+      indices.refresh:
+        index: test
+
+---
+# Delete Index when connection is teardown
+teardown:
+  - do:
+      indices.delete:
+        index: test
+
+---
+# Verify that mappings under the catalog field did not expand
+# and no dynamic fields were created.
+"Mappings":
+  - skip:
+      version: " - 2.6.99"
+      reason: "flat_object is introduced in 2.7.0"
+
+  - do:
+      indices.get_mapping:
+        index: test
+  - is_true: test.mappings
+  - match: { test.mappings.properties.ISBN13.type:  keyword     }
+  - match: { test.mappings.properties.catalog.type: flat_object }
+  - match: { test.mappings.properties.required_matches.type: long }
+  # https://github.com/opensearch-project/OpenSearch/tree/main/rest-api-spec/src/main/resources/rest-api-spec/test#length
+  - length: { test.mappings.properties: 3 }
+  - length: { test.mappings.properties.catalog: 1 }
+
+---
+"Supported queries":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+  # Verify Document Count
+  - do:
+      search:
+        body: {
+          query: {
+            match_all: {}
+          }
+        }
+
+  - length:   { hits.hits: 2  }
+
+  # Match Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            match: { "catalog.title": "Lucene in Action"}
+          }
+        }
+
+  - length:   { hits.hits: 1  }
+  - match: { hits.hits.0._source.catalog.title: "Lucene in Action" }
+
+  # Match Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            match: { catalog: "Lucene in Action"}
+          }
+        }
+
+  - length:   { hits.hits: 1  }
+  - match: { hits.hits.0._source.catalog.title: "Lucene in Action" }
+
+
+  # Multi Match Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            multi_match: {
+              "query":    "Mike",
+              "fields": [ "ISBN13", "catalog" ]
+            }
+          }
+        }
+
+  - length:   { hits.hits: 1  }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Multi Match Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            multi_match: {
+              "query": "Mike",
+              "fields": [ "ISBN13", "catalog.author.given" ]
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Term Query1 with dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog.publishDate: "2015-01-01"}
+          }
+        }
+
+  - length:   { hits.hits: 1  }
+  - match: { hits.hits.0._source.catalog.publishDate: "2015-01-01" }
+
+  # Term Query1 without dot path for date
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog: "2015-01-01" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.publishDate: "2015-01-01" }
+
+  # Term Query2 with dot path for string
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { "catalog.author.given": "Mike" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Term Query2 without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog: "Mike" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Term Query3 with dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog.location: "-12.7982" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.location:  [-12.7982,33.3847 ]}
+
+  # Term Query3 without dot path for array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog: "-12.7982" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.location:  [-12.7982,33.3847 ]}
+
+
+  # Term Query4 with  dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog.review: "99.8" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.review: [ [ "great",99.8 ],[ "ok",80.0 ] ] }
+
+  # Term Query4 without dot path for nested-array
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            term: { catalog: "99.8" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.review:  [["great",99.8],["ok",80.0]] }
+
+  # Terms Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            terms: { catalog: ["John","Mike"] }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Terms Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            terms: { catalog.author.given: ["John","Mike"] }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Termset Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "terms_set": {
+              "catalog": {
+                "terms": [  "John","Mike" ],
+                "minimum_should_match_field": "required_matches"}
+            }
+          }
+        }
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Termset Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "terms_set": {
+              "catalog.author.given": {
+                "terms": [  "John","Mike" ],
+                "minimum_should_match_field": "required_matches"}
+            }
+          }
+        }
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Prefix Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "prefix": {
+              "catalog.author.given": {
+                "value": "Mi"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Prefix Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "prefix": {
+              "catalog": {
+                "value": "Mi"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Range Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog.catalogId": {
+                "gte": "c-0000",
+                "lte": "c-0006"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.catalogId: "c-0002" }
+
+  # Range Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog": {
+                "gte": "c-0000",
+                "lte": "c-0006"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.catalogId: "c-0002" }
+
+  # Range Query with integer input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog.quantity": {
+                "gte": 1000,
+                "lte": 2000
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.quantity: 1234 }
+
+  # Range Query with integer input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog": {
+                "gte": 1000,
+                "lte": 2000
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.quantity: 1234 }
+
+  # Range Query with date input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog.publishDate": {
+                "gte": "2015-01-01",
+                "lte": "2015-12-31"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.publishDate: "2015-01-01" }
+
+  # Range Query with date input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog": {
+                "gte": "2015-01-01",
+                "lte": "2015-12-31"
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.publishDate: "2015-01-01" }
+
+  # Range Query with double input with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog.location": {
+                "gte": 40.1234,
+                "lte": 42.1234
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.location: [-81.7982,41.3847] }
+
+  # Range Query with double input without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "range": {
+              "catalog": {
+                "gte": 40.1234,
+                "lte": 42.1234
+              }
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.location: [ -81.7982,41.3847 ] }
+
+  # Exists Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": catalog.catalogId
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Exists Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "exists": {
+              "field": catalog
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
+  # Query_string Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "query_string": {
+              "fields": [ "catalog", "ISBN13" ],
+              "query": "John OR Mike"
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "query_string": {
+              "fields": [ "catalog.author.given", "ISBN13" ],
+              "query": "John OR Mike"
+            }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+  - match: { hits.hits.0._source.catalog.author.given: "Mike" }
+
+  # Simple_query_string Query without dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "simple_query_string" : {
+              "query": "Doe",
+              "fields": ["catalog", "ISBN13"]
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.surname: "Doe" }
+
+
+  # Simple_query_string Query with dot path.
+  - do:
+      search:
+        body: {
+          _source: true,
+          query: {
+            "simple_query_string": {
+              "query": "Doe",
+              "fields": [ "catalog.author.surname", "ISBN13" ]
+            }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.catalog.author.surname: "Doe" }
+
+---
+"Unsupported":
+  - skip:
+      version: " - 2.99.99"
+      reason: "flat_object is introduced in 3.0.0 in main branch"
+
+  # Mapping parameters (such as index/search analyzers) are currently not supported
+  # The plan is to support them in the next version
+  - do:
+      catch: bad_request
+      indices.create:
+        index: test_analyzer
+        body:
+          mappings:
+            properties:
+              data:
+                type : "flat_object"
+                analyzer: "standard"
+
+  - match: { error.root_cause.0.type: "mapper_parsing_exception" }
+  - match: { error.root_cause.0.reason: "Mapping definition for [data] has unsupported parameters:  [analyzer : standard]"}
+  - match: { status: 400 }
+
+  # Wildcard Query with dot path.
+  - do:
+      catch: bad_request
+      search:
+        body: {
+          _source: true,
+          query: {
+            "wildcard": {
+              "catalog.title": "Mock*"
+            }
+          }
+        }
+  - match: { error.root_cause.0.type: "query_shard_exception" }
+  - match: { error.root_cause.0.reason: "Can only use wildcard queries on keyword and text fields - not on [catalog.title] which is of type [flat_object]"}
+  - match: { status: 400 }
+
+  # Wildcard Query without dot path.
+  - do:
+      catch: bad_request
+      search:
+        body: {
+          _source: true,
+          query: {
+            "wildcard": {
+              "catalog": "Mock*"
+            }
+          }
+        }
+  - match: { error.root_cause.0.type: "query_shard_exception" }
+  - match: { error.root_cause.0.reason: "Can only use wildcard queries on keyword and text fields - not on [catalog] which is of type [flat_object]" }
+  - match: { status: 400 }
+
+  # Aggregation and Match Query with dot path.
+  - do:
+      catch: bad_request
+      search:
+        body: {
+          _source: true,
+          size: 0,
+          query: {
+            "match": {
+              "ISBN13": "V9781933988177"
+            }
+          },
+          aggs: {
+            "avg_rating": {
+              "avg": {
+                "field": "catalog.rating"
+              }
+            }
+          }
+        }
+  - match: { error.root_cause.0.type: "illegal_argument_exception" }
+  - match: { error.root_cause.0.reason: "Field [catalog.rating] of type [flat_object] is not supported for aggregation [avg]" }
+  - match: { status: 400 }
+
+  # Aggregation using average and Match Query with dot path.
+  - do:
+      catch: bad_request
+      search:
+        body: {
+          _source: true,
+          size: 0,
+          query: {
+            "match": {
+              "ISBN13": "V9781933988177"
+            }
+          },
+          aggs: {
+            "avg_rating": {
+              "avg": {
+                "field": "catalog.rating"
+              }
+            }
+          }
+        }
+  - match: { error.root_cause.0.type: "illegal_argument_exception" }
+  - match: { error.root_cause.0.reason: "Field [catalog.rating] of type [flat_object] is not supported for aggregation [avg]" }
+  - match: { status: 400 }
+
+  # Aggregation using geolocation and Match Query with dot path.
+  - do:
+      catch: bad_request
+      search:
+        body: {
+          _source: true,
+          size: 0,
+          query: {
+            "match": {
+              "ISBN13": "V9781933988177"
+            }
+          },
+          aggs: {
+            "books_in_location": {
+              "geo_distance": {
+                "field": "catalog.location",
+                "origin": "41.3847,-81.7982",
+                "unit": "km",
+                "ranges": [
+                  {
+                    "to": 100
+                  }
+                ]
+              },
+              "aggs": {
+                "total_books": {
+                  "sum": {
+                    "field": "catalog.quantity"
+                  }
+                }
+              }
+            }
+          }
+        }
+  - match: { error.root_cause.0.type: "illegal_argument_exception" }
+  - match: { error.root_cause.0.reason: "Field [catalog.location] of type [flat_object] is not supported for aggregation [geo_distance]" }
+  - match: { status: 400 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_unsigned_long.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_unsigned_long.yml
new file mode 100644
index 0000000000000..02157a809d90b
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/index/90_unsigned_long.yml
@@ -0,0 +1,73 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          settings:
+            number_of_replicas: 0
+          mappings:
+            properties:
+              counter:
+                type: unsigned_long
+
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+              _id: 1
+          - counter: "10223372036854775807.23"
+
+---
+"Unsigned long with decimal part test":
+
+  - do:
+      search:
+        index: test_1
+        rest_total_hits_as_int: true
+        body:
+          query:
+            term:
+              counter:
+                value: 10223372036854775807
+
+  - match: { hits.total: 1 }
+
+---
+"Stored unsigned long with decimal part test":
+  - do:
+      indices.create:
+        index: test_2
+        body:
+          settings:
+            number_of_replicas: 0
+          mappings:
+            properties:
+              counter:
+                type: unsigned_long
+                store: true
+
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_2
+              _id: 2
+          - counter: "10223372036854775807"
+
+  - do:
+      search:
+        index: test_*
+        rest_total_hits_as_int: true
+        body:
+          query:
+            term:
+              counter:
+                value: 10223372036854775807
+
+  - match: { hits.total: 2 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/10_basic.yml
index a4d1841ed7108..38848945d9f1f 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/10_basic.yml
@@ -31,6 +31,7 @@ setup:
   - skip:
       version: " - 7.3.99"
       reason: index cloning was added in 7.4.0
+      features: allowed_warnings
   # make it read-only
   - do:
       indices.put_settings:
@@ -46,6 +47,8 @@ setup:
 
   # now we do the actual clone
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.clone:
         index: "source"
         target: "target"
@@ -94,9 +97,12 @@ setup:
   - skip:
       version: " - 7.3.99"
       reason: index cloning was added in 7.4.0
+      features: allowed_warnings
   # try to do an illegal clone with illegal number_of_shards
   - do:
       catch: /illegal_argument_exception/
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.clone:
         index: "source"
         target: "target"
@@ -106,3 +112,99 @@ setup:
           settings:
             index.number_of_replicas: 0
             index.number_of_shards: 6
+
+---
+"Returns error if target index's metadata write is blocked":
+
+  - skip:
+      version: " - 2.7.99"
+      reason: "only available in 2.8.0 and above"
+
+  # block source index's write operations
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # set `index.blocks.read_only` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.clone:
+        index: "source"
+        target: "new_cloned_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.blocks.read_only: true
+
+  # set `index.blocks.metadata` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.clone:
+        index: "source"
+        target: "new_cloned_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.blocks.metadata: true
+
+  # set source index's setting `index.blocks.read_only` to `true`
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: true
+
+  - do:
+      catch: /illegal_argument_exception/
+      indices.clone:
+        index: "source"
+        target: "new_cloned_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+
+  # overwrite the source index's setting, everything is fine
+  - do:
+      indices.clone:
+        index: "source"
+        target: "new_cloned_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.blocks.read_only: null
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+
+  - do:
+      get:
+        index: new_cloned_index
+        id:    "1"
+
+  - match: { _index:   new_cloned_index }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # clear the source index's read_only blocks because it will block deleting index
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: null
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/20_source_mapping.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/20_source_mapping.yml
index 625f574fa73de..21c476c76965c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/20_source_mapping.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/20_source_mapping.yml
@@ -3,6 +3,7 @@
   - skip:
       version: " - 7.3.99"
       reason: index cloning was added in 7.4.0
+      features: allowed_warnings
   # create index
   - do:
       indices.create:
@@ -50,6 +51,8 @@
 
   # now we do the actual clone
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.clone:
         index: "source"
         target: "target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/30_copy_settings.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/30_copy_settings.yml
index 503cc15609072..b0bd8056cb004 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/30_copy_settings.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/30_copy_settings.yml
@@ -3,7 +3,7 @@
   - skip:
       version: " - 7.3.99"
       reason: index cloning was added in 7.4.0
-      features: [arbitrary_key]
+      features: [arbitrary_key, allowed_warnings]
 
   - do:
       nodes.info:
@@ -36,6 +36,8 @@
 
   # now we do an actual clone and copy settings
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.clone:
         index: "source"
         target: "copy-settings-target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/40_wait_for_completion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/40_wait_for_completion.yml
new file mode 100644
index 0000000000000..310375ef8471e
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/40_wait_for_completion.yml
@@ -0,0 +1,88 @@
+---
+"Clone index with wait_for_completion":
+  # clone index with wait_for_completion parameter, when the parameter is set to false, the API
+  # will return a task immediately and the clone operation will run in background.
+
+  - skip:
+      version: " - 2.6.99"
+      reason: "only available in 2.7+"
+      features: allowed_warnings
+
+  - do:
+      nodes.info:
+        node_id: data:true
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      indices.create:
+        index: source
+        wait_for_active_shards: 1
+        body:
+          settings:
+            # ensure everything is allocated on the same data node
+            index.routing.allocation.include._id: $node_id
+            index.number_of_shards: 1
+            index.number_of_replicas: 0
+  - do:
+      index:
+        index: source
+        id:    "1"
+        body:  { "foo": "hello world" }
+
+  - do:
+      get:
+        index: source
+        id:    "1"
+
+  - match: { _index:   source }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # make it read-only
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # clone with wait_for_completion
+  - do:
+      indices.clone:
+        index: "source"
+        target: "new_cloned_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        wait_for_completion: false
+        task_execution_timeout: 30s
+        body:
+          settings:
+            index.number_of_shards: 1
+            "index.number_of_replicas": 0
+
+  - match: { task: /^.+$/ }
+  - set: { task: taskId }
+
+  - do:
+      tasks.get:
+        wait_for_completion: true
+        task_id: $taskId
+  - match: { task.action: "indices:admin/resize" }
+  - match: { task.description: "clone from [source] to [new_cloned_index]" }
+
+  # .tasks index is created when the clone index operation completes, so we should delete .tasks index finally,
+  # if not, the .tasks index may introduce unexpected warnings and then cause other test cases to fail.
+  # Delete the .tasks index directly will also introduce warning, but currently we don't have such APIs which can delete one
+  # specified task or clear all completed tasks, so we have to do so. Expect we can introduce more tasks related APIs in future
+  - do:
+      allowed_warnings:
+        - "this request accesses system indices: [.tasks], but in a future major version, direct access to system indices will be prevented by default"
+      indices.delete:
+        index: .tasks
+        ignore_unavailable: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/10_basic.yml
index 74684901579a4..43a6f656c09c3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/10_basic.yml
@@ -28,6 +28,6 @@
       indices.get_alias:
         index: testind
         name:  testali
-  
+
   - match: { 'status': 404 }
   - match: { 'error': 'alias [testali] missing' }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/all_path_options.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/all_path_options.yml
index d1d01cbaaa7e6..67369b67b3249 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/all_path_options.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_alias/all_path_options.yml
@@ -221,4 +221,3 @@ setup:
       catch: param
       indices.delete_alias:
         index: "test_index1"
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_template/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_template/10_basic.yml
index 67592a013e8f1..32b692b16c5d6 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_template/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_template/10_basic.yml
@@ -6,6 +6,8 @@ setup:
         ignore: [404]
 ---
 "Test indices.exists_template":
+  - skip:
+      features: allowed_warnings
 
   - do:
       indices.exists_template:
@@ -23,6 +25,8 @@ setup:
             number_of_replicas: 0
 
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.exists_template:
         name: test
         master_timeout: 1m
@@ -37,4 +41,3 @@ setup:
         local: true
 
   - is_false: ''
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/10_basic.yml
index 137736e6823a9..d62c4c8882b13 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/10_basic.yml
@@ -27,5 +27,3 @@
         index: test
         max_num_segments: 10
         only_expunge_deletes: true
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/20_wait_for_completion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/20_wait_for_completion.yml
new file mode 100644
index 0000000000000..1d6c63558bb59
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.forcemerge/20_wait_for_completion.yml
@@ -0,0 +1,39 @@
+---
+"Force merge index with wait_for_completion":
+  # force merge index with wait_for_completion parameter, when the parameter is set to false, the API
+  # will return a task immediately and the merge process will run in background.
+
+  - skip:
+      version: " - 2.6.99"
+      reason: "only available in 2.7+"
+      features: allowed_warnings
+
+  - do:
+      indices.create:
+        index: test_index
+
+  - do:
+      indices.forcemerge:
+        index: test_index
+        wait_for_completion: false
+        max_num_segments: 1
+  - match: { task: /^.+$/ }
+  - set: { task: taskId }
+
+  - do:
+      tasks.get:
+        wait_for_completion: true
+        task_id: $taskId
+  - match: { task.action: "indices:admin/forcemerge" }
+  - match: { task.description: "Force-merge indices [test_index], maxSegments[1], onlyExpungeDeletes[false], flush[true]" }
+
+  # .tasks index is created when the force-merge operation completes, so we should delete .tasks index finally,
+  # if not, the .tasks index may introduce unexpected warnings and then cause other test cases to fail.
+  # Delete the .tasks index directly will also introduce warning, but currently we don't have such APIs which can delete one
+  # specified task or clear all completed tasks, so we have to do so. Expect we can introduce more tasks related APIs in future
+  - do:
+      allowed_warnings:
+        - "this request accesses system indices: [.tasks], but in a future major version, direct access to system indices will be prevented by default"
+      indices.delete:
+        index: .tasks
+        ignore_unavailable: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/40_missing_index.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/40_missing_index.yml
index 7c7b07b587849..690f83d5f3c2b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/40_missing_index.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/40_missing_index.yml
@@ -6,5 +6,3 @@
       indices.get_field_mapping:
         index: test_index
         fields: field
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/50_field_wildcards.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/50_field_wildcards.yml
index 2c9ff58b445df..814bd1e3a4063 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/50_field_wildcards.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_field_mapping/50_field_wildcards.yml
@@ -127,4 +127,3 @@ setup:
   - match:  {test_index_2.mappings.t1.full_name: t1 }
   - match:  {test_index_2.mappings.t2.full_name: t2 }
   - length: {test_index_2.mappings: 2}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_index_template/20_get_missing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_index_template/20_get_missing.yml
index 2dfa466ba0eca..4c855d928d1c0 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_index_template/20_get_missing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_index_template/20_get_missing.yml
@@ -17,4 +17,3 @@ setup:
       catch:  missing
       indices.get_index_template:
         name: test
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
index 1bbfbc4f4c967..e9502cdc08436 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
@@ -29,4 +29,3 @@
         index: test_index
         ignore_unavailable: true
         allow_no_indices: false
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_settings/20_aliases.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_settings/20_aliases.yml
index da7678202ed34..4f8d1371d90b1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_settings/20_aliases.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_settings/20_aliases.yml
@@ -23,4 +23,3 @@
   - match: { test-index.settings.index.number_of_replicas: "3" }
   - match: { test-index.settings.index.number_of_shards: "2" }
   - match: { test-index.settings.index.refresh_interval: "-1" }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/10_basic.yml
index 9becbd54a3773..32536f8f72650 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/10_basic.yml
@@ -72,8 +72,12 @@ setup:
 
 ---
 "Get template with flat settings and master timeout":
+  - skip:
+      features: allowed_warnings
 
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.get_template:
         name: test
         flat_settings: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/20_get_missing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/20_get_missing.yml
index 2751f57dacb6c..ee7ba62c9beb4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/20_get_missing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_template/20_get_missing.yml
@@ -10,4 +10,3 @@ setup:
       catch:  missing
       indices.get_template:
         name: test
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/20_multiple_indices.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/20_multiple_indices.yml
index bef5ea8a54651..2720b08514ba3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/20_multiple_indices.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/20_multiple_indices.yml
@@ -101,4 +101,3 @@ setup:
       search:
         rest_total_hits_as_int: true
         index: test_index3
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/30_wait_for_completion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/30_wait_for_completion.yml
new file mode 100644
index 0000000000000..f5af642d82f77
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/30_wait_for_completion.yml
@@ -0,0 +1,50 @@
+---
+"Open index with wait_for_completion":
+  # open index with wait_for_completion parameter, when the parameter is set to false, the API
+  # will return a task immediately and the open operation will run in background.
+
+  - skip:
+      version: " - 2.6.99"
+      reason: "only available in 2.7+"
+      features: allowed_warnings
+
+  - do:
+      indices.create:
+        index: test_index
+        body:
+          settings:
+            number_of_replicas: 0
+            number_of_shards: 1
+
+  - do:
+      indices.close:
+        index: test_index
+  - is_true: acknowledged
+
+  - do:
+      indices.open:
+        index: test_index
+        wait_for_active_shards: all
+        cluster_manager_timeout: 10s
+        wait_for_completion: false
+        task_execution_timeout: 30s
+  - match: { task: /^.+$/ }
+  - set: { task: taskId }
+
+  - do:
+      tasks.get:
+        wait_for_completion: true
+        task_id: $taskId
+  - match: { task.action: "indices:admin/open" }
+  - match: { task.description: "open indices [test_index]" }
+
+  # .tasks index is created when the open index operation completes, so we should delete .tasks index finally,
+  # if not, the .tasks index may introduce unexpected warnings and then cause other test cases to fail.
+  # Delete the .tasks index directly will also introduce warning, but currently we don't have such APIs which can delete one
+  # specified task or clear all completed tasks, so we have to do so. Expect we can introduce more tasks related APIs in future
+  - do:
+      allowed_warnings:
+        - "this request accesses system indices: [.tasks], but in a future major version, direct access to system indices will be prevented by default"
+      indices.delete:
+        index: .tasks
+        ignore_unavailable: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_alias/all_path_options.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_alias/all_path_options.yml
index bef57bbddf165..47828c43350b7 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_alias/all_path_options.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_alias/all_path_options.yml
@@ -113,4 +113,3 @@ setup:
   - do:
       catch: param
       indices.put_alias: {}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/10_basic.yml
index 36317c7ae173c..23f87ea1ec2b3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/10_basic.yml
@@ -143,4 +143,3 @@
 
   - is_false: test_index.mappings.properties.foo.meta.bar
   - match: { test_index.mappings.properties.foo.meta.baz: "quux" }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/all_path_options.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/all_path_options.yml
index c1daa76fe3d6e..ca7a21df20ea4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/all_path_options.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_mapping/all_path_options.yml
@@ -159,4 +159,3 @@ setup:
       indices.get_mapping: {}
 
   - match: {test_index1.mappings.properties.text.type:     text}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_settings/all_path_options.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_settings/all_path_options.yml
index 07f1956f0fcca..ac45c4e098e6e 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_settings/all_path_options.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.put_settings/all_path_options.yml
@@ -110,4 +110,3 @@ setup:
   - match: {test_index1.settings.index.refresh_interval:     1s}
   - match: {test_index2.settings.index.refresh_interval:     1s}
   - match: {foo.settings.index.refresh_interval:     1s}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.refresh/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.refresh/10_basic.yml
index 6e493a0cce936..bf20d51bc97cd 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.refresh/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.refresh/10_basic.yml
@@ -55,4 +55,3 @@ setup:
   - match: { _shards.total: 0 }
   - match: { _shards.successful: 0 }
   - match: { _shards.failed: 0 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/10_basic.yml
index dc68ffc9a3b86..a36db0cda8526 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/10_basic.yml
@@ -148,4 +148,3 @@
         body:
           conditions:
             max_docs: 1
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/20_max_doc_condition.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/20_max_doc_condition.yml
index f5d223259dc06..7d1b447b4e293 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/20_max_doc_condition.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/20_max_doc_condition.yml
@@ -52,4 +52,3 @@
 
   - match: { conditions: { "[max_docs: 2]": true } }
   - match: { rolled_over: true }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/10_basic.yml
index a5b1cb8607b3a..0c95f01c1e4b8 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/10_basic.yml
@@ -1,12 +1,11 @@
 ---
-"Shrink index via API":
+setup:
   # creates an index with one document solely allocated on a particular data node
   # and shrinks it into a new index with a single shard
   # we don't do the relocation to a single node after the index is created
   # here since in a mixed version cluster we can't identify
   # which node is the one with the highest version and that is the only one that can safely
   # be used to shrink the index.
-
   - do:
       nodes.info:
         node_id: data:true
@@ -29,14 +28,10 @@
         id:    "1"
         body:  { "foo": "hello world" }
 
-  - do:
-      get:
-        index: source
-        id:    "1"
-
-  - match: { _index:   source }
-  - match: { _id:      "1"     }
-  - match: { _source:  { foo: "hello world" } }
+---
+"Shrink index via API":
+  - skip:
+      features: allowed_warnings
 
   # make it read-only
   - do:
@@ -53,6 +48,8 @@
 
   # now we do the actual shrink
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.shrink:
         index: "source"
         target: "target"
@@ -74,3 +71,103 @@
   - match: { _index:   target }
   - match: { _id:      "1"     }
   - match: { _source:  { foo: "hello world" } }
+
+---
+"Returns error if target index's metadata write is blocked":
+
+  - skip:
+      version: " - 2.7.99"
+      reason: "only available in 2.8.0 and above"
+
+  # block source index's write operations
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # set `index.blocks.read_only` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 1
+            index.blocks.read_only: true
+
+  # set `index.blocks.metadata` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 1
+            index.blocks.metadata: true
+
+  # set source index's setting `index.blocks.read_only` to `true`
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: true
+
+  - do:
+      catch: /illegal_argument_exception/
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 1
+
+  # overwrite the source index's setting, everything is fine
+  - do:
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 1
+            index.blocks.read_only: null
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+
+  - do:
+      get:
+        index: new_shrunken_index
+        id:    "1"
+
+  - match: { _index:   new_shrunken_index }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # clear the source index's read_only blocks because it will block deleting index
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: null
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/20_source_mapping.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/20_source_mapping.yml
index dec0760fc6b19..8d08373208216 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/20_source_mapping.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/20_source_mapping.yml
@@ -3,7 +3,7 @@
     - skip:
         version: " - 6.9.99"
         reason: expects warnings that pre-7.0.0 will not send
-        features: [warnings, arbitrary_key]
+        features: [warnings, arbitrary_key, allowed_warnings]
 
     - do:
         nodes.info:
@@ -60,6 +60,8 @@
 
     # now we do the actual shrink
     - do:
+        allowed_warnings:
+          - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
         indices.shrink:
           index: "source"
           target: "target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/30_copy_settings.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/30_copy_settings.yml
index a744895c4ce38..07d5076550889 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/30_copy_settings.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/30_copy_settings.yml
@@ -46,7 +46,8 @@
             index.number_of_replicas: 0
             index.merge.scheduler.max_thread_count: 2
       allowed_warnings:
-        - "parameter [copy_settings] is deprecated and will be removed in 8.0.0"
+        - "parameter [copy_settings] is deprecated and will be removed in 3.0.0"
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
 
   - do:
       cluster.health:
@@ -64,6 +65,8 @@
 
   # now we do a actual shrink and copy settings (by default)
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.shrink:
         index: "source"
         target: "default-copy-settings-target"
@@ -91,6 +94,8 @@
   # now we do a actual shrink and try to set no copy settings
   - do:
       catch: /illegal_argument_exception/
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.shrink:
         index: "source"
         target: "explicit-no-copy-settings-target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/40_max_shard_size.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/40_max_shard_size.yml
new file mode 100644
index 0000000000000..cc8fd9b025da4
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/40_max_shard_size.yml
@@ -0,0 +1,82 @@
+---
+"Shrink index with max_shard_size":
+  # shrink index with max_shard_size parameter, which is used to generate an optimum
+  # number_of_shards for the target index.
+
+  - skip:
+      version: " - 2.4.99"
+      reason: "only available in 2.5+"
+      features: allowed_warnings
+
+  - do:
+      nodes.info:
+        node_id: data:true
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      indices.create:
+        index: source
+        wait_for_active_shards: 1
+        body:
+          settings:
+            # ensure everything is allocated on the same data node
+            index.routing.allocation.include._id: $node_id
+            index.number_of_shards: 3
+            index.number_of_replicas: 0
+  - do:
+      index:
+        index: source
+        id:    "1"
+        body:  { "foo": "hello world" }
+
+  - do:
+      get:
+        index: source
+        id:    "1"
+
+  - match: { _index:   source }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # make it read-only
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # shrink with max_shard_size
+  - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        master_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+          max_shard_size: "10gb"
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+
+  - do:
+      get:
+        index: "new_shrunken_index"
+        id:    "1"
+
+  - do:
+      indices.get_settings:
+        index: "new_shrunken_index"
+
+  - match: { new_shrunken_index.settings.index.number_of_shards: "1" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/50_wait_for_completion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/50_wait_for_completion.yml
new file mode 100644
index 0000000000000..f1b06fc1fa392
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/50_wait_for_completion.yml
@@ -0,0 +1,88 @@
+---
+"Shrink index with wait_for_completion":
+  # shrink index with wait_for_completion parameter, when the parameter is set to false, the API
+  # will return a task immediately and the shrink operation will run in background.
+
+  - skip:
+      version: " - 2.6.99"
+      reason: "only available in 2.7+"
+      features: allowed_warnings
+
+  - do:
+      nodes.info:
+        node_id: data:true
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      indices.create:
+        index: source
+        wait_for_active_shards: 1
+        body:
+          settings:
+            # ensure everything is allocated on the same data node
+            index.routing.allocation.include._id: $node_id
+            index.number_of_shards: 3
+            index.number_of_replicas: 0
+  - do:
+      index:
+        index: source
+        id:    "1"
+        body:  { "foo": "hello world" }
+
+  - do:
+      get:
+        index: source
+        id:    "1"
+
+  - match: { _index:   source }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # make it read-only
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # shrink with wait_for_completion
+  - do:
+      indices.shrink:
+        index: "source"
+        target: "new_shrunken_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        wait_for_completion: false
+        task_execution_timeout: 30s
+        body:
+          settings:
+            index.number_of_shards: 1
+            "index.number_of_replicas": 0
+
+  - match: { task: /^.+$/ }
+  - set: { task: taskId }
+
+  - do:
+      tasks.get:
+        wait_for_completion: true
+        task_id: $taskId
+  - match: { task.action: "indices:admin/resize" }
+  - match: { task.description: "shrink from [source] to [new_shrunken_index]" }
+
+  # .tasks index is created when the shrink index operation completes, so we should delete .tasks index finally,
+  # if not, the .tasks index may introduce unexpected warnings and then cause other test cases to fail.
+  # Delete the .tasks index directly will also introduce warning, but currently we don't have such APIs which can delete one
+  # specified task or clear all completed tasks, so we have to do so. Expect we can introduce more tasks related APIs in future
+  - do:
+      allowed_warnings:
+        - "this request accesses system indices: [.tasks], but in a future major version, direct access to system indices will be prevented by default"
+      indices.delete:
+        index: .tasks
+        ignore_unavailable: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/10_basic.yml
index 4ae1d0002a237..970c97ab517cf 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/10_basic.yml
@@ -29,6 +29,9 @@ setup:
 
 ---
 "Split index via API":
+  - skip:
+      features: allowed_warnings
+
   # make it read-only
   - do:
       indices.put_settings:
@@ -44,6 +47,8 @@ setup:
 
   # now we do the actual split
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "target"
@@ -90,6 +95,8 @@ setup:
 
 ---
 "Split from 1 to N":
+  - skip:
+      features: allowed_warnings
   - do:
       indices.create:
         index: source_one_shard
@@ -131,6 +138,8 @@ setup:
 
   # now we do the actual split from 1 to 5
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source_one_shard"
         target: "target"
@@ -176,9 +185,14 @@ setup:
 
 ---
 "Create illegal split indices":
+  - skip:
+      features: allowed_warnings
+
   # try to do an illegal split with number_of_routing_shards set
   - do:
       catch: /illegal_argument_exception/
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "target"
@@ -193,6 +207,8 @@ setup:
   # try to do an illegal split with illegal number_of_shards
   - do:
       catch: /illegal_state_exception/
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "target"
@@ -202,3 +218,103 @@ setup:
           settings:
             index.number_of_replicas: 0
             index.number_of_shards: 6
+
+---
+"Returns error if target index's metadata write is blocked":
+
+  - skip:
+      version: " - 2.7.99"
+      reason: "only available in 2.8.0 and above"
+
+  # block source index's write operations
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # set `index.blocks.read_only` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.split:
+        index: "source"
+        target: "new_split_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 4
+            index.blocks.read_only: true
+
+  # set `index.blocks.metadata` to `true` for target index
+  - do:
+      catch: /action_request_validation_exception/
+      indices.split:
+        index: "source"
+        target: "new_split_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 4
+            index.blocks.metadata: true
+
+  # set source index's setting `index.blocks.read_only` to `true`
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: true
+
+  - do:
+      catch: /illegal_argument_exception/
+      indices.split:
+        index: "source"
+        target: "new_split_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 4
+
+  # overwrite the source index's setting, everything is fine
+  - do:
+      indices.split:
+        index: "source"
+        target: "new_split_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        body:
+          settings:
+            index.number_of_replicas: 0
+            index.number_of_shards: 4
+            index.blocks.read_only: null
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+
+  - do:
+      get:
+        index: new_split_index
+        id:    "1"
+
+  - match: { _index:   new_split_index }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # clear the source index's read_only blocks because it will block deleting index
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.read_only: null
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/20_source_mapping.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/20_source_mapping.yml
index c86e49aac0561..2c878157f468e 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/20_source_mapping.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/20_source_mapping.yml
@@ -1,5 +1,8 @@
 ---
 "Split index ignores target template mapping":
+  - skip:
+      features: allowed_warnings
+
   # create index
   - do:
       indices.create:
@@ -48,6 +51,8 @@
 
   # now we do the actual split
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/30_copy_settings.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/30_copy_settings.yml
index 0ceacf1f064ca..b8e6b54a393b9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/30_copy_settings.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/30_copy_settings.yml
@@ -48,8 +48,8 @@
             index.number_of_shards: 2
             index.merge.scheduler.max_thread_count: 2
       allowed_warnings:
-        - "parameter [copy_settings] is deprecated and will be removed in 8.0.0"
-
+        - "parameter [copy_settings] is deprecated and will be removed in 3.0.0"
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
 
   - do:
       cluster.health:
@@ -67,6 +67,8 @@
 
   # now we do a actual shrink and copy settings (by default)
   - do:
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "default-copy-settings-target"
@@ -94,6 +96,8 @@
 
   - do:
       catch: /illegal_argument_exception/
+      allowed_warnings:
+        - "Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead."
       indices.split:
         index: "source"
         target: "explicit-no-copy-settings-target"
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/40_wait_for_completion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/40_wait_for_completion.yml
new file mode 100644
index 0000000000000..92c906134a5f2
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/40_wait_for_completion.yml
@@ -0,0 +1,88 @@
+---
+"Split index with wait_for_completion":
+  # split index with wait_for_completion parameter, when the parameter is set to false, the API
+  # will return a task immediately and the split operation will run in background.
+
+  - skip:
+      version: " - 2.6.99"
+      reason: "only available in 2.7+"
+      features: allowed_warnings
+
+  - do:
+      nodes.info:
+        node_id: data:true
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      indices.create:
+        index: source
+        wait_for_active_shards: 1
+        body:
+          settings:
+            # ensure everything is allocated on the same data node
+            index.routing.allocation.include._id: $node_id
+            index.number_of_shards: 1
+            index.number_of_replicas: 0
+  - do:
+      index:
+        index: source
+        id:    "1"
+        body:  { "foo": "hello world" }
+
+  - do:
+      get:
+        index: source
+        id:    "1"
+
+  - match: { _index:   source }
+  - match: { _id:      "1"     }
+  - match: { _source:  { foo: "hello world" } }
+
+  # make it read-only
+  - do:
+      indices.put_settings:
+        index: source
+        body:
+          index.blocks.write: true
+          index.number_of_replicas: 0
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+        index: source
+
+  # split with wait_for_completion
+  - do:
+      indices.split:
+        index: "source"
+        target: "new_split_index"
+        wait_for_active_shards: 1
+        cluster_manager_timeout: 10s
+        wait_for_completion: false
+        task_execution_timeout: 30s
+        body:
+          settings:
+            index.number_of_shards: 2
+            "index.number_of_replicas": 0
+
+  - match: { task: /^.+$/ }
+  - set: { task: taskId }
+
+  - do:
+      tasks.get:
+        wait_for_completion: true
+        task_id: $taskId
+  - match: { task.action: "indices:admin/resize" }
+  - match: { task.description: "split from [source] to [new_split_index]" }
+
+  # .tasks index is created when the split index operation completes, so we should delete .tasks index finally,
+  # if not, the .tasks index may introduce unexpected warnings and then cause other test cases to fail.
+  # Delete the .tasks index directly will also introduce warning, but currently we don't have such APIs which can delete one
+  # specified task or clear all completed tasks, so we have to do so. Expect we can introduce more tasks related APIs in future
+  - do:
+      allowed_warnings:
+        - "this request accesses system indices: [.tasks], but in a future major version, direct access to system indices will be prevented by default"
+      indices.delete:
+        index: .tasks
+        ignore_unavailable: true
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.update_aliases/20_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.update_aliases/20_routing.yml
index ecedcef0c1a48..c812d84dfe7e3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.update_aliases/20_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.update_aliases/20_routing.yml
@@ -132,4 +132,3 @@ setup:
         index: test_index
 
   - match: {test_index.aliases.test_alias: {'index_routing': '5', 'search_routing': '5'}}
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.upgrade/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.upgrade/10_basic.yml
index 55070cb8c1f97..62c1a51dace52 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.upgrade/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.upgrade/10_basic.yml
@@ -69,4 +69,3 @@
       indices.upgrade:
         index: ["test_index", "does_not_exist"]
         ignore_unavailable: false
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/info/20_lucene_version.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/info/20_lucene_version.yml
index 83414fbabc565..427a585815db0 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/info/20_lucene_version.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/info/20_lucene_version.yml
@@ -2,6 +2,3 @@
 "Lucene Version":
     - do:         {info: {}}
     - is_true:    version.lucene_version
-
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/nodes.stats/11_indices_metrics.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/nodes.stats/11_indices_metrics.yml
index a09619b7255c3..784c7b52b18b4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/nodes.stats/11_indices_metrics.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/nodes.stats/11_indices_metrics.yml
@@ -138,6 +138,35 @@
   - is_false:  nodes.$node_id.indices.translog
   - is_false:  nodes.$node_id.indices.recovery
 
+---
+"Metric - indexing doc_status":
+  - skip:
+      version: " - 2.10.99"
+      reason: "Doc Status Stats were introduced in v2.11.0"
+  - do:
+      nodes.info: {}
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      nodes.stats: { metric: indices, index_metric: indexing }
+
+  - is_false: nodes.$node_id.indices.docs
+  - is_false: nodes.$node_id.indices.store
+  - is_true: nodes.$node_id.indices.indexing
+  - is_true: nodes.$node_id.indices.indexing.doc_status
+  - is_false: nodes.$node_id.indices.get
+  - is_false: nodes.$node_id.indices.search
+  - is_false: nodes.$node_id.indices.merges
+  - is_false: nodes.$node_id.indices.refresh
+  - is_false: nodes.$node_id.indices.flush
+  - is_false: nodes.$node_id.indices.warmer
+  - is_false: nodes.$node_id.indices.query_cache
+  - is_false: nodes.$node_id.indices.fielddata
+  - is_false: nodes.$node_id.indices.completion
+  - is_false: nodes.$node_id.indices.segments
+  - is_false: nodes.$node_id.indices.translog
+  - is_false: nodes.$node_id.indices.recovery
 
 ---
 "Metric - recovery":
@@ -224,4 +253,3 @@
   - is_false:  nodes.$node_id.indices.translog
   - is_false:  nodes.$node_id.indices.recovery
   - is_true:   nodes.$node_id.indices.segments.file_sizes
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/ping/10_ping.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/ping/10_ping.yml
index ec07c218dabd9..da160503caab4 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/ping/10_ping.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/ping/10_ping.yml
@@ -2,4 +2,3 @@
 "Ping":
     - do:      { ping: {}}
     - is_true: ''
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/pit/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/pit/10_basic.yml
new file mode 100644
index 0000000000000..9d1ee7571f2e2
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/pit/10_basic.yml
@@ -0,0 +1,144 @@
+"Create PIT, Search with PIT ID and Delete":
+  - skip:
+      version: " - 2.3.99"
+      reason: "mode to be introduced later than 2.4"
+  - do:
+      indices.create:
+        index: test_pit
+  - do:
+      index:
+        index:  test_pit
+        id:     42
+        body:   { foo: 1 }
+
+  - do:
+      index:
+        index:  test_pit
+        id:     43
+        body:   { foo: 2 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      create_pit:
+        allow_partial_pit_creation: true
+        index: test_pit
+        keep_alive: 23h
+
+  - set: {pit_id: pit_id}
+  - match:   { _shards.failed: 0}
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        size: 1
+        sort: foo
+        body:
+          query:
+            match_all: {}
+          pit: {"id": "$pit_id"}
+
+  - match: {hits.total:      2    }
+  - length: {hits.hits:      1    }
+  - match: {hits.hits.0._id: "42" }
+
+  - do:
+      index:
+        index:  test_pit
+        id:     44
+        body:   { foo: 3 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        size: 1
+        sort: foo
+        body:
+          query:
+            match_all: {}
+          pit: {"id": "$pit_id", "keep_alive":"10m"}
+
+  - match: {hits.total:      2    }
+  - length: {hits.hits:      1    }
+  - match: {hits.hits.0._id: "42" }
+
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test_pit
+        size: 1
+        sort: foo
+        body:
+          query:
+            match_all: {}
+
+  - match: {hits.total:      3    }
+  - length: {hits.hits:      1    }
+
+  - do:
+      get_all_pits: {}
+
+  - match: {pits.0.pit_id: $pit_id}
+  - match: {pits.0.keep_alive: 82800000 }
+
+  - do:
+      delete_pit:
+        body:
+          "pit_id": [$pit_id]
+
+  - match: {pits.0.pit_id: $pit_id}
+  - match: {pits.0.successful: true }
+
+---
+"Delete all":
+  - skip:
+      version: " - 2.3.99"
+      reason: "mode to be introduced later than 2.4"
+  - do:
+      indices.create:
+        index: test_pit
+  - do:
+      index:
+        index:  test_pit
+        id:     42
+        body:   { foo: 1 }
+
+  - do:
+      index:
+        index:  test_pit
+        id:     43
+        body:   { foo: 2 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      create_pit:
+        allow_partial_pit_creation: true
+        index: test_pit
+        keep_alive: 23h
+
+  - set: {pit_id: pit_id}
+  - match:   { _shards.failed: 0}
+
+  - do:
+      get_all_pits: {}
+
+  - match: {pits.0.pit_id: $pit_id}
+  - match: {pits.0.keep_alive: 82800000 }
+
+  - do:
+      delete_all_pits: {}
+
+  - match: {pits.0.pit_id: $pit_id}
+  - match: {pits.0.successful: true }
+
+  - do:
+      delete_all_pits: {}
+
+  - match: {pits: []}
+  - length: {pits: 0}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/scroll/10_basic_timeseries.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/scroll/10_basic_timeseries.yml
new file mode 100644
index 0000000000000..1995bee89a0a4
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/scroll/10_basic_timeseries.yml
@@ -0,0 +1,161 @@
+---
+"Basic scroll on time series workload for reversed leaf sorter":
+  - do:
+      indices.create:
+        index: test_scroll_time_series
+        body:
+          mappings:
+            properties:
+              name:
+                type: keyword
+              '@timestamp':
+                type: date
+
+  - do:
+      bulk:
+        refresh: true
+        index: test_scroll_time_series
+        body:
+          - '{"index": {}}'
+          - '{"name": "1", "@timestamp": "2010-03-12T01:07:00"}'
+          - '{"index": {}}'
+          - '{"name": "2", "@timestamp": "2010-03-12T01:07:01"}'
+          - '{"index": {}}'
+          - '{"name": "3", "@timestamp": "2010-03-12T01:07:02"}'
+          - '{"index": {}}'
+          - '{"name": "4", "@timestamp": "2010-03-12T01:07:03"}'
+          - '{"index": {}}'
+          - '{"name": "5", "@timestamp": "2010-03-12T01:07:04"}'
+          - '{"index": {}}'
+          - '{"name": "6", "@timestamp": "2010-03-12T01:07:05"}'
+          - '{"index": {}}'
+          - '{"name": "7", "@timestamp": "2010-03-12T01:07:06"}'
+          - '{"index": {}}'
+          - '{"name": "8", "@timestamp": "2010-03-12T01:07:07"}'
+          - '{"index": {}}'
+          - '{"name": "9", "@timestamp": "2010-03-12T01:07:08"}'
+          - '{"index": {}}'
+          - '{"name": "10", "@timestamp": "2010-03-12T01:07:09"}'
+  - do:
+      indices.refresh: {}
+  - do:
+      bulk:
+        refresh: true
+        index: test_scroll_time_series
+        body:
+          - '{"index": {}}'
+          - '{"name": "11", "@timestamp": "2010-03-12T01:07:10"}'
+          - '{"index": {}}'
+          - '{"name": "12", "@timestamp": "2010-03-12T01:07:11"}'
+          - '{"index": {}}'
+          - '{"name": "13", "@timestamp": "2010-03-12T01:07:12"}'
+          - '{"index": {}}'
+          - '{"name": "14", "@timestamp": "2010-03-12T01:07:13"}'
+          - '{"index": {}}'
+          - '{"name": "15", "@timestamp": "2010-03-12T01:07:14"}'
+          - '{"index": {}}'
+          - '{"name": "16", "@timestamp": "2010-03-12T01:07:15"}'
+          - '{"index": {}}'
+          - '{"name": "17", "@timestamp": "2010-03-12T01:07:16"}'
+          - '{"index": {}}'
+          - '{"name": "18", "@timestamp": "2010-03-12T01:07:17"}'
+          - '{"index": {}}'
+          - '{"name": "19", "@timestamp": "2010-03-12T01:07:18"}'
+          - '{"index": {}}'
+          - '{"name": "20", "@timestamp": "2010-03-12T01:07:19"}'
+  - do:
+      indices.refresh: { }
+  - do:
+      bulk:
+        refresh: true
+        index: test_scroll_time_series
+        body:
+          - '{"index": {}}'
+          - '{"name": "21", "@timestamp": "2010-03-12T01:07:20"}'
+          - '{"index": {}}'
+          - '{"name": "22", "@timestamp": "2010-03-12T01:07:21"}'
+          - '{"index": {}}'
+          - '{"name": "23", "@timestamp": "2010-03-12T01:07:22"}'
+          - '{"index": {}}'
+          - '{"name": "24", "@timestamp": "2010-03-12T01:07:23"}'
+          - '{"index": {}}'
+          - '{"name": "25", "@timestamp": "2010-03-12T01:07:24"}'
+          - '{"index": {}}'
+          - '{"name": "26", "@timestamp": "2010-03-12T01:07:25"}'
+          - '{"index": {}}'
+          - '{"name": "27", "@timestamp": "2010-03-12T01:07:26"}'
+          - '{"index": {}}'
+          - '{"name": "28", "@timestamp": "2010-03-12T01:07:27"}'
+          - '{"index": {}}'
+          - '{"name": "29", "@timestamp": "2010-03-12T01:07:28"}'
+          - '{"index": {}}'
+          - '{"name": "30", "@timestamp": "2010-03-12T01:07:29"}'
+  - do:
+      indices.refresh: { }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test_scroll_time_series
+        size: 5
+        scroll: 1m
+        sort: _doc
+        body:
+          query:
+            match_all: {}
+
+  - set: {_scroll_id: scroll_id}
+  - match: {hits.total:      30    }
+  - length: {hits.hits:      5    }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m"}
+
+  - match: {hits.total:      30    }
+  - length: {hits.hits:      5    }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m" }
+
+  - match: { hits.total: 30 }
+  - length: { hits.hits: 5 }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m" }
+
+  - match: { hits.total: 30 }
+  - length: { hits.hits: 5 }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m" }
+
+  - match: { hits.total: 30 }
+  - length: { hits.hits: 5 }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m" }
+
+  - match: { hits.total: 30 }
+  - length: { hits.hits: 5 }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m" }
+
+  - match: { hits.total: 30 }
+  - length: { hits.hits: 0 }
+
+  - do:
+      clear_scroll:
+        scroll_id: $scroll_id
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/100_avg_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/100_avg_metric_unsigned.yml
new file mode 100644
index 0000000000000..4a04b48f55444
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/100_avg_metric_unsigned.yml
@@ -0,0 +1,168 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213695000.0 }
+  - match: { aggregations.the_double_avg.value: 2555843009213695000.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213695000.0 }
+  - match: { aggregations.the_double_avg.value: 2555843009213695000.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_avg.value: 3407790678951593500.0 }
+  - match: { aggregations.the_double_avg.value: 3407790678951593500.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_avg:
+              avg:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_avg.value: 1 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_avg:
+              avg:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_avg.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_avg:
+              meta:
+                foo: bar
+              avg:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_avg.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/110_max_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/110_max_metric_unsigned.yml
new file mode 100644
index 0000000000000..e8bab4c933eb5
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/110_max_metric_unsigned.yml
@@ -0,0 +1,168 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 101
+             double_field: 101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213694500.0 }
+  - match: { aggregations.the_double_avg.value: 2555843009213694500.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213694500.0 }
+  - match: { aggregations.the_double_avg.value: 2555843009213694500.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_avg:
+              avg:
+                field: unsigned_field
+            the_double_avg:
+              avg:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_avg.value: 3407790678951592400.0 }
+  - match: { aggregations.the_double_avg.value: 3407790678951592400.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_avg:
+              avg:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_avg.value: 1 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_avg:
+              avg:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_avg.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_avg:
+              meta:
+                foo: bar
+              avg:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_avg.value: 2555843009213694500.0 }
+  - match: { aggregations.the_unsigned_avg.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/120_min_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/120_min_metric_unsigned.yml
new file mode 100644
index 0000000000000..38601f3ea660d
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/120_min_metric_unsigned.yml
@@ -0,0 +1,168 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 101
+             double_field: 101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_min:
+              min:
+                field: unsigned_field
+            the_double_min:
+              min:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_min.value: 1.0 }
+  - match: { aggregations.the_double_min.value: 1.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_min:
+              min:
+                field: unsigned_field
+            the_double_min:
+              min:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_min.value: 1.0 }
+  - match: { aggregations.the_double_min.value: 1.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_min:
+              min:
+                field: unsigned_field
+            the_double_min:
+              min:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_min.value: 51.0 }
+  - match: { aggregations.the_double_min.value: 51.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_min:
+              min:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_min.value: 1.0 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_min:
+              min:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_min.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_min:
+              meta:
+                foo: bar
+              min:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_min.value: 1.0 }
+  - match: { aggregations.the_unsigned_min.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/130_sum_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/130_sum_metric_unsigned.yml
new file mode 100644
index 0000000000000..2c2cce1a24022
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/130_sum_metric_unsigned.yml
@@ -0,0 +1,168 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_sum:
+              sum:
+                field: unsigned_field
+            the_double_sum:
+              sum:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_sum.value: 10223372036854780000.0 }
+  - match: { aggregations.the_double_sum.value: 10223372036854780000.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_sum:
+              sum:
+                field: unsigned_field
+            the_double_sum:
+              sum:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_sum.value: 10223372036854780000.0 }
+  - match: { aggregations.the_double_sum.value: 10223372036854780000.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_sum:
+              sum:
+                field: unsigned_field
+            the_double_sum:
+              sum:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_sum.value: 10223372036854780000.0 }
+  - match: { aggregations.the_double_sum.value: 10223372036854780000.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_sum:
+              sum:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_sum.value: 4.0 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_sum:
+              sum:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_sum.value: 0.0 }
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_sum:
+              meta:
+                foo: bar
+              sum:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_sum.value: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_sum.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/140_value_count_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/140_value_count_metric_unsigned.yml
new file mode 100644
index 0000000000000..7f8ee96142676
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/140_value_count_metric_unsigned.yml
@@ -0,0 +1,180 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 101
+             double_field: 101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_value_count:
+              value_count:
+                field: unsigned_field
+            the_double_value_count:
+              value_count:
+                field: double_field
+            the_string_value_count:
+              value_count:
+                field: string_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_value_count.value: 4 }
+  - match: { aggregations.the_double_value_count.value: 4 }
+  - match: { aggregations.the_string_value_count.value: 4 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_value_count:
+              value_count:
+                field: unsigned_field
+            the_double_value_count:
+              value_count:
+                field: double_field
+            the_string_value_count:
+              value_count:
+                field: string_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_value_count.value: 4 }
+  - match: { aggregations.the_double_value_count.value: 4 }
+  - match: { aggregations.the_string_value_count.value: 4 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_value_count:
+              value_count:
+                field: unsigned_field
+            the_double_value_count:
+              value_count:
+                field: double_field
+            the_string_value_count:
+              value_count:
+                field: string_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_value_count.value: 3 }
+  - match: { aggregations.the_double_value_count.value: 3 }
+  - match: { aggregations.the_string_value_count.value: 3 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_value_count:
+              value_count:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_value_count.value: 4 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_value_count:
+              value_count:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_value_count.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_value_count:
+              meta:
+                foo: bar
+              value_count:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_value_count.value: 4 }
+  - match: { aggregations.the_unsigned_value_count.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/150_stats_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/150_stats_metric_unsigned.yml
new file mode 100644
index 0000000000000..717af8fe15ae8
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/150_stats_metric_unsigned.yml
@@ -0,0 +1,199 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_stats:
+              stats:
+                field: unsigned_field
+            the_double_stats:
+              stats:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_stats.count: 4 }
+  - match: { aggregations.the_unsigned_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_stats.count: 4 }
+  - match: { aggregations.the_double_stats.min: 1.0 }
+  - match: { aggregations.the_double_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_double_stats.sum: 10223372036854780000.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_stats:
+              stats:
+                field: unsigned_field
+            the_double_stats:
+              stats:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_stats.count: 4 }
+  - match: { aggregations.the_unsigned_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_stats.count: 4 }
+  - match: { aggregations.the_double_stats.min: 1.0 }
+  - match: { aggregations.the_double_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_double_stats.sum: 10223372036854780000.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_stats:
+              stats:
+                field: unsigned_field
+            the_double_stats:
+              stats:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_stats.count: 3 }
+  - match: { aggregations.the_unsigned_stats.min: 51.0 }
+  - match: { aggregations.the_unsigned_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_stats.avg: 3407790678951593500.0 }
+  - match: { aggregations.the_unsigned_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_stats.count: 3 }
+  - match: { aggregations.the_double_stats.min: 51.0 }
+  - match: { aggregations.the_double_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_stats.avg: 3407790678951593500.0 }
+  - match: { aggregations.the_double_stats.sum: 10223372036854780000.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_stats:
+              stats:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_stats.count: 4 }
+  - match: { aggregations.the_missing_stats.min: 1.0 }
+  - match: { aggregations.the_missing_stats.max: 1.0 }
+  - match: { aggregations.the_missing_stats.avg: 1.0 }
+  - match: { aggregations.the_missing_stats.sum: 4.0 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_stats:
+              stats:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_stats.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_stats:
+              meta:
+                foo: bar
+              stats:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_stats.count: 4 }
+  - match: { aggregations.the_unsigned_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_stats.sum: 10223372036854780000.0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/160_extended_stats_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/160_extended_stats_metric_unsigned.yml
new file mode 100644
index 0000000000000..f2090cd081394
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/160_extended_stats_metric_unsigned.yml
@@ -0,0 +1,276 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_extended_stats:
+              extended_stats:
+                field: unsigned_field
+            the_double_extended_stats:
+              extended_stats:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.count: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation:  4426849948127849000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.upper: 11409542905469393000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.lower: -6297856887042003000.0 }
+  - match: { aggregations.the_double_extended_stats.count: 4 }
+  - match: { aggregations.the_double_extended_stats.min: 1.0 }
+  - match: { aggregations.the_double_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_double_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.upper: 11409542905469393000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.lower: -6297856887042003000.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_unsigned_extended_stats:
+              extended_stats:
+                field: unsigned_field
+            the_double_extended_stats:
+              extended_stats:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_unsigned_extended_stats.count: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.variance: 19597000463239538000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.upper: 11409542905469393000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.lower: -6297856887042003000.0 }
+  - match: { aggregations.the_double_extended_stats.count: 4 }
+  - match: { aggregations.the_double_extended_stats.min: 1.0 }
+  - match: { aggregations.the_double_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_double_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_double_extended_stats.variance: 19597000463239538000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.upper: 11409542905469393000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.lower: -6297856887042003000.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            the_unsigned_extended_stats:
+              extended_stats:
+                field: unsigned_field
+            the_double_extended_stats:
+              extended_stats:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.the_unsigned_extended_stats.count: 3 }
+  - match: { aggregations.the_unsigned_extended_stats.min: 51.0 }
+  - match: { aggregations.the_unsigned_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.avg: 3407790678951593500.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.variance: 23226074623098710000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation: 4819343795901959000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.upper: 13046478270755512000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.lower: -6230896912852324000.0 }
+  - match: { aggregations.the_double_extended_stats.count: 3 }
+  - match: { aggregations.the_double_extended_stats.min: 51.0 }
+  - match: { aggregations.the_double_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_extended_stats.avg: 3407790678951593500.0 }
+  - match: { aggregations.the_double_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.variance: 23226074623098710000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation: 4819343795901959000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.upper: 13046478270755512000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.lower: -6230896912852324000.0 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_extended_stats:
+              extended_stats:
+                field: foo
+                missing: 1
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_missing_extended_stats.count: 4 }
+  - match: { aggregations.the_missing_extended_stats.min: 1.0 }
+  - match: { aggregations.the_missing_extended_stats.max: 1.0 }
+  - match: { aggregations.the_missing_extended_stats.avg: 1.0 }
+  - match: { aggregations.the_missing_extended_stats.sum: 4.0 }
+  - match: { aggregations.the_missing_extended_stats.sum_of_squares: 4.0 }
+  - match: { aggregations.the_missing_extended_stats.variance: 0.0 }
+  - match: { aggregations.the_missing_extended_stats.std_deviation: 0.0 }
+  - match: { aggregations.the_missing_extended_stats.std_deviation_bounds.upper: 1.0 }
+  - match: { aggregations.the_missing_extended_stats.std_deviation_bounds.lower: 1.0 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_missing_extended_stats:
+              extended_stats:
+                field: foo
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.the_missing_extended_stats.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_extended_stats:
+              meta:
+                foo: bar
+              extended_stats:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.count: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.upper: 11409542905469393000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.lower: -6297856887042003000.0 }
+
+---
+"Sigma test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_extended_stats:
+              extended_stats:
+                field: unsigned_field
+                sigma: 3
+            the_double_extended_stats:
+              extended_stats:
+                field: double_field
+                sigma: 3
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.count: 4 }
+  - match: { aggregations.the_unsigned_extended_stats.min: 1.0 }
+  - match: { aggregations.the_unsigned_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.variance: 19597000463239537000000000000000000000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.upper: 15836392853597241000.0 }
+  - match: { aggregations.the_unsigned_extended_stats.std_deviation_bounds.lower: -10724706835169853000.0 }
+  - match: { aggregations.the_double_extended_stats.count: 4 }
+  - match: { aggregations.the_double_extended_stats.min: 1.0 }
+  - match: { aggregations.the_double_extended_stats.max: 10223372036854778000.0 }
+  - match: { aggregations.the_double_extended_stats.avg: 2555843009213695000.0 }
+  - match: { aggregations.the_double_extended_stats.sum: 10223372036854780000.0 }
+  - match: { aggregations.the_double_extended_stats.sum_of_squares: 104517335803944210000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.variance: 19597000463239537000000000000000000000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation: 4426849948127849000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.upper: 15836392853597241000.0 }
+  - match: { aggregations.the_double_extended_stats.std_deviation_bounds.lower: -10724706835169853000.0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/170_cardinality_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/170_cardinality_metric_unsigned.yml
new file mode 100644
index 0000000000000..27245d1aa435c
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/170_cardinality_metric_unsigned.yml
@@ -0,0 +1,287 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+            distinct_double:
+              cardinality:
+                field: double_field
+            distinct_string:
+              cardinality:
+                field: string_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.distinct_unsigned.value: 4 }
+  - match: { aggregations.distinct_double.value: 4 }
+  - match: { aggregations.distinct_string.value: 1 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+                precision_threshold: 100
+            distinct_double:
+              cardinality:
+                field: double_field
+                precision_threshold: 100
+            distinct_string:
+              cardinality:
+                field: string_field
+                precision_threshold: 100
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.distinct_unsigned.value: 4 }
+  - match: { aggregations.distinct_double.value: 4 }
+  - match: { aggregations.distinct_string.value: 1 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+            distinct_double:
+              cardinality:
+                field: double_field
+            distinct_string:
+              cardinality:
+                field: string_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.distinct_unsigned.value: 4 }
+  - match: { aggregations.distinct_double.value: 4 }
+  - match: { aggregations.distinct_string.value: 1 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+            distinct_double:
+              cardinality:
+                field: double_field
+            distinct_string:
+              cardinality:
+                field: string_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { aggregations.distinct_unsigned.value: 3 }
+  - match: { aggregations.distinct_double.value: 3 }
+  - match: { aggregations.distinct_string.value: 1 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_missing:
+              cardinality:
+                field: missing_field
+                missing: "foo"
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.distinct_missing.value: 1 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_missing:
+              cardinality:
+                field: missing_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.distinct_missing.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_missing:
+              meta:
+                foo: bar
+              cardinality:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.distinct_missing.value: 4 }
+  - match: { aggregations.distinct_missing.meta.foo: "bar" }
+
+---
+"Invalid Precision test":
+
+  - do:
+      catch: /\[precisionThreshold\] must be greater than or equal to 0. Found \[-1\] in \[distinct_unsigned\]/
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+                precision_threshold: -1
+
+---
+"profiler unsigned_long":
+  - do:
+      search:
+        body:
+          profile: true
+          size: 0
+          aggs:
+            distinct_unsigned:
+              cardinality:
+                field: unsigned_field
+  - match: { aggregations.distinct_unsigned.value: 4 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.initialize: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_leaf_collector: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.collect: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_aggregation: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.post_collection: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.empty_collectors_used: 0 }
+  - gt: { profile.shards.0.aggregations.0.debug.numeric_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.ordinals_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.ordinals_collectors_overhead_too_high: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.string_hashing_collectors_used: 0 }
+
+---
+"profiler double":
+  - do:
+      search:
+        body:
+          profile: true
+          size: 0
+          aggs:
+            distinct_double:
+              cardinality:
+                field: double_field
+  - match: { aggregations.distinct_double.value: 4 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.initialize: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_leaf_collector: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.collect: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_aggregation: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.post_collection: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.empty_collectors_used: 0 }
+  - gt: { profile.shards.0.aggregations.0.debug.numeric_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.ordinals_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.ordinals_collectors_overhead_too_high: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.string_hashing_collectors_used: 0 }
+
+---
+"profiler string":
+  - do:
+      search:
+        body:
+          profile: true
+          size: 0
+          aggs:
+            distinct_string:
+              cardinality:
+                field: string_field
+  - match: { aggregations.distinct_string.value: 1 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.initialize: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_leaf_collector: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.collect: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.build_aggregation: 0 }
+  - gt: { profile.shards.0.aggregations.0.breakdown.post_collection: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.empty_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.numeric_collectors_used: 0 }
+  - gt: { profile.shards.0.aggregations.0.debug.ordinals_collectors_used: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.ordinals_collectors_overhead_too_high: 0 }
+  - match: { profile.shards.0.aggregations.0.debug.string_hashing_collectors_used: 0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/180_percentiles_tdigest_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/180_percentiles_tdigest_metric_unsigned.yml
new file mode 100644
index 0000000000000..b572be74e908b
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/180_percentiles_tdigest_metric_unsigned.yml
@@ -0,0 +1,588 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match:  { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Basic 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match:  { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Compression 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                tdigest:
+                  compression: 200
+            percentiles_double:
+              percentiles:
+                field: double_field
+                tdigest:
+                  compression: 200
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Compression 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                tdigest:
+                  compression: 200
+            percentiles_double:
+              percentiles:
+                field: double_field
+                tdigest:
+                  compression: 200
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Only aggs 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Only aggs 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Filtered 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 313.5 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 7667529027641084000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 313.5 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 7667529027641084000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Filtered 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+            percentiles_double:
+              percentiles:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+  - match:  { aggregations.percentiles_double.values.1\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.5\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_double.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_double.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_double.values.99\.0: 10223372036854778000.0 }
+
+---
+"Metadata 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              meta:
+                foo: bar
+              percentiles:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.percentiles_unsigned.meta.foo: "bar" }
+
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 26.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 576.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 5111686018427390000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+---
+"Metadata 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              meta:
+                foo: bar
+              percentiles:
+                field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.percentiles_unsigned.meta.foo: "bar" }
+
+
+  - match:  { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+  - match:  { aggregations.percentiles_unsigned.values.75\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.95\.0: 10223372036854778000.0 }
+  - match:  { aggregations.percentiles_unsigned.values.99\.0: 10223372036854778000.0 }
+
+---
+"Explicit Percents 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+            percentiles_double:
+              percentiles:
+                field: double_field
+                percents: [5.0, 25.0, 50.0]
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 26.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 576.0 }
+
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 26.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 576.0 }
+
+---
+"Explicit Percents 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+            percentiles_double:
+              percentiles:
+                field: double_field
+                percents: [5.0, 25.0, 50.0]
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 1101.0 }
+
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 1101.0 }
+
+---
+"Non-keyed 2.x test":
+  - skip:
+      version: "3.0.0 -"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "- 2.99.99"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+                keyed: false
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.0.key:  5.0 }
+  - match:  { aggregations.percentiles_unsigned.values.0.value:  1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.key:  25.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.value:  26.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.key:  50.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.value:  576.0 }
+
+---
+"Non-keyed 3.x test":
+  - skip:
+      version: "- 2.99.99"
+      features: node_selector
+      reason:  "t-digest 3.2 was interpolating leading to incorrect percentiles"
+
+  - do:
+      node_selector:
+        version: "3.0.0 -"
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+                keyed: false
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match:  { aggregations.percentiles_unsigned.values.0.key:  5.0 }
+  - match:  { aggregations.percentiles_unsigned.values.0.value:  1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.key:  25.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.value:  51.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.key:  50.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.value:  1101.0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric.yml
index 32c349c5e46b6..fd7e17306abd9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric.yml
@@ -160,6 +160,16 @@ setup:
 ---
 "Filtered test":
 
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+              _id:    5
+          - int_field: 126
+            double_field: 126.0
+            string_field: foo
   - do:
       search:
         rest_total_hits_as_int: true
@@ -180,14 +190,14 @@ setup:
                 field: double_field
                 hdr: {}
 
-  - match: { hits.total: 3 }
-  - length: { hits.hits: 3 }
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
 
   - match: { aggregations.percentiles_int.values.1\.0: 51.0 }
   - match: { aggregations.percentiles_int.values.5\.0: 51.0 }
   - match: { aggregations.percentiles_int.values.25\.0: 51.0 }
   - match: { aggregations.percentiles_int.values.50\.0: 101.03125 }
-  - match: { aggregations.percentiles_int.values.75\.0: 101.03125 }
+  - match: { aggregations.percentiles_int.values.75\.0: 126.03125 }
   - match: { aggregations.percentiles_int.values.95\.0: 151.09375 }
   - match: { aggregations.percentiles_int.values.99\.0: 151.09375 }
 
@@ -195,7 +205,7 @@ setup:
   - match: { aggregations.percentiles_double.values.5\.0: 51.0 }
   - match: { aggregations.percentiles_double.values.25\.0: 51.0 }
   - match: { aggregations.percentiles_double.values.50\.0: 101.03125 }
-  - match: { aggregations.percentiles_double.values.75\.0: 101.03125 }
+  - match: { aggregations.percentiles_double.values.75\.0: 126.03125 }
   - match: { aggregations.percentiles_double.values.95\.0: 151.09375 }
   - match: { aggregations.percentiles_double.values.99\.0: 151.09375 }
 
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric_unsigned.yml
new file mode 100644
index 0000000000000..f45be4632d3bd
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/190_percentiles_hdr_metric_unsigned.yml
@@ -0,0 +1,344 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+              number_of_shards: 5
+              number_of_routing_shards: 5
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 1425497558138880
+             double_field: 1425497558138880.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                hdr: {}
+            percentiles_double:
+              percentiles:
+                field: double_field
+                hdr: {}
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_unsigned.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_unsigned.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_unsigned.values.99\.0: 1426066581225472 }
+
+  - match: { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_double.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_double.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_double.values.99\.0: 1426066581225472 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                hdr:
+                  number_of_significant_value_digits: 3
+            percentiles_double:
+              percentiles:
+                field: double_field
+                hdr:
+                  number_of_significant_value_digits: 3
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_unsigned.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_unsigned.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_unsigned.values.99\.0: 1426066581225472 }
+
+  - match: { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_double.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_double.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_double.values.99\.0: 1426066581225472 }
+
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                hdr: {}
+            percentiles_double:
+              percentiles:
+                field: double_field
+                hdr: {}
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+
+  - match: { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_unsigned.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_unsigned.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_unsigned.values.99\.0: 1426066581225472 }
+
+  - match: { aggregations.percentiles_double.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_double.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_double.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_double.values.99\.0: 1426066581225472 }
+
+
+---
+"Filtered test":
+
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+              _id:    5
+          - unsigned_field: 126
+            double_field: 126.0
+            string_field: foo
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 50
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                hdr: {}
+            percentiles_double:
+              percentiles:
+                field: double_field
+                hdr: {}
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.1\.0: 51.0 }
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 51.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 51.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 126.03125 }
+  - match: { aggregations.percentiles_unsigned.values.75\.0: 1101.96875 }
+  - match: { aggregations.percentiles_unsigned.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_unsigned.values.99\.0: 1426066581225472 }
+
+  - match: { aggregations.percentiles_double.values.1\.0: 51.0 }
+  - match: { aggregations.percentiles_double.values.5\.0: 51.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 51.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 126.03125 }
+  - match: { aggregations.percentiles_double.values.75\.0: 1101.96875 }
+  - match: { aggregations.percentiles_double.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_double.values.99\.0: 1426066581225472 }
+
+
+---
+"Missing field with missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_missing:
+              percentiles:
+                field: missing_field
+                missing: 1.0
+                hdr: {}
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_missing.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.50\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.75\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.95\.0: 1.0 }
+  - match: { aggregations.percentiles_missing.values.99\.0: 1.0 }
+
+---
+"Missing field without missing param":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_missing:
+              percentiles:
+                field: missing_field
+                hdr: {}
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - is_false: aggregations.percentiles_missing.value
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              meta:
+                foo: bar
+              percentiles:
+                field: unsigned_field
+                hdr: {}
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.percentiles_unsigned.meta.foo: "bar" }
+
+  - match: { aggregations.percentiles_unsigned.values.1\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 51.0302734375 }
+  - match: { aggregations.percentiles_unsigned.values.75\.0: 1101.9990234375 }
+  - match: { aggregations.percentiles_unsigned.values.95\.0: 1426066581225472 }
+  - match: { aggregations.percentiles_unsigned.values.99\.0: 1426066581225472 }
+
+---
+"Explicit Percents test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+                hdr: {}
+            percentiles_double:
+              percentiles:
+                field: double_field
+                percents: [5.0, 25.0, 50.0]
+                hdr: {}
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+  - match: { aggregations.percentiles_unsigned.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_unsigned.values.50\.0: 51.0302734375 }
+
+
+  - match: { aggregations.percentiles_double.values.5\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.25\.0: 1.0 }
+  - match: { aggregations.percentiles_double.values.50\.0: 51.0302734375 }
+
+
+---
+"Non-keyed test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            percentiles_unsigned:
+              percentiles:
+                field: unsigned_field
+                percents: [5.0, 25.0, 50.0]
+                keyed: false
+                hdr: {}
+
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+
+
+  - match:  { aggregations.percentiles_unsigned.values.0.key:  5.0 }
+  - match:  { aggregations.percentiles_unsigned.values.0.value:  1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.key:  25.0 }
+  - match:  { aggregations.percentiles_unsigned.values.1.value:  1.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.key:  50.0 }
+  - match:  { aggregations.percentiles_unsigned.values.2.value:  51.0302734375 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml
index 7c7a223044725..0fa734b7e5fe9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml
@@ -245,6 +245,106 @@ setup:
 
   - match: { aggregations.integer_terms.buckets.1.doc_count: 1 }
 
+---
+"Long test":
+  - do:
+      index:
+        index: test_1
+        id: 1
+        body: { "number": 4611686018427387903 }
+
+  - do:
+      index:
+        index: test_1
+        id: 2
+        body: { "number": -4611686018427387904 }
+
+  - do:
+      index:
+        index: test_1
+        id: 3
+        body: { "number": 4611686018427387903 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "long_terms" : { "terms" : { "field" : "number" } } } }
+
+  - match: { hits.total: 3 }
+
+  - length: { aggregations.long_terms.buckets: 2 }
+
+  - match: { aggregations.long_terms.buckets.0.key: 4611686018427387903 }
+
+  - is_false: aggregations.long_terms.buckets.0.key_as_string
+
+  - match: { aggregations.long_terms.buckets.0.doc_count: 2 }
+
+  - match: { aggregations.long_terms.buckets.1.key: -4611686018427387904 }
+
+  - is_false: aggregations.long_terms.buckets.1.key_as_string
+
+  - match: { aggregations.long_terms.buckets.1.doc_count: 1 }
+
+---
+"Unsigned Long test":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.put_mapping:
+        index: test_1
+        body:
+          properties:
+            unsigned:
+              type: unsigned_long
+
+  - do:
+      index:
+        index: test_1
+        id: 1
+        body: { "unsigned": 18446744073709551615 }
+
+  - do:
+      index:
+        index: test_1
+        id: 2
+        body: { "unsigned": 10223372036854775807 }
+
+  - do:
+      index:
+        index: test_1
+        id: 3
+        body: { "unsigned": 18446744073709551615 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "unsigned_terms" : { "terms" : { "field" : "unsigned" } } } }
+
+  - match: { hits.total: 3 }
+
+  - length: { aggregations.unsigned_terms.buckets: 2 }
+
+  - match: { aggregations.unsigned_terms.buckets.0.key: 18446744073709551615 }
+
+  - is_false: aggregations.unsigned_terms.buckets.0.key_as_string
+
+  - match: { aggregations.unsigned_terms.buckets.0.doc_count: 2 }
+
+  - match: { aggregations.unsigned_terms.buckets.1.key: 10223372036854775807 }
+
+  - is_false: aggregations.unsigned_terms.buckets.1.key_as_string
+
+  - match: { aggregations.unsigned_terms.buckets.1.doc_count: 1 }
+
 ---
 "Double test":
   - do:
@@ -567,6 +667,41 @@ setup:
 
   - match: { aggregations.long_terms.buckets.0.doc_count: 1 }
 
+---
+"Unmapped unsigned longs":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.put_mapping:
+        index: test_1
+        body:
+          properties:
+            unsigned:
+              type: unsigned_long
+  - do:
+      index:
+        index: test_1
+        id: 1
+        body: {}
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "unsigned_terms" : { "terms" : { "field" : "unmapped_unsigned", "value_type" : "unsigned_long", "missing": 3 } } } }
+
+  - match: { hits.total: 1 }
+
+  - length: { aggregations.unsigned_terms.buckets: 1 }
+
+  - match: { aggregations.unsigned_terms.buckets.0.key: 3 }
+
+  - match: { aggregations.unsigned_terms.buckets.0.doc_count: 1 }
+
 ---
 "Unmapped doubles":
 
@@ -649,6 +784,95 @@ setup:
 
   - match: { aggregations.number_terms.buckets.2.doc_count: 1 }
 
+---
+"Mixing longs, unsigned  long and doubles":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.put_mapping:
+        index: test_1
+        body:
+          properties:
+            unsigned:
+              type: unsigned_long
+
+  - do:
+      indices.create:
+          index: test_3
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                number:
+                  type: unsigned_long
+
+  - do:
+      index:
+        index: test_1
+        id: 1
+        body: {"number": 100}
+
+  - do:
+      index:
+        index: test_1
+        id: 2
+        body: {"number": 10}
+
+  - do:
+      index:
+        index: test_2
+        id: 3
+        body: {"number": 100.0}
+
+  - do:
+      index:
+        index: test_2
+        id: 1
+        body: {"number": 10.0}
+
+  - do:
+      index:
+        index: test_2
+        id: 2
+        body: {"number": 14.6}
+
+  - do:
+      index:
+        index: test_3
+        id: 1
+        body: {"number": 10223372036854775807}
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "number_terms" : { "terms" : { "field" : "number" } } } }
+
+  - match: { hits.total: 6 }
+
+  - length: { aggregations.number_terms.buckets: 4 }
+
+  - match: { aggregations.number_terms.buckets.0.key: 10.0 }
+
+  - match: { aggregations.number_terms.buckets.0.doc_count: 2 }
+
+  - match: { aggregations.number_terms.buckets.1.key: 100.0 }
+
+  - match: { aggregations.number_terms.buckets.1.doc_count: 2 }
+
+  - match: { aggregations.number_terms.buckets.2.key: 14.6 }
+
+  - match: { aggregations.number_terms.buckets.2.doc_count: 1 }
+
+  - match: { aggregations.number_terms.buckets.3.key: 10223372036854775807.0 }
+
+  - match: { aggregations.number_terms.buckets.3.doc_count: 1 }
+
 ---
 "Deprecated _term order":
 
@@ -824,6 +1048,7 @@ setup:
       indices.forcemerge:
         index: test_1
         max_num_segments: 1
+        flush: true
 
   - do:
       search:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/220_filters_bucket_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/220_filters_bucket_unsigned.yml
new file mode 100644
index 0000000000000..68943bf42c2b8
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/220_filters_bucket_unsigned.yml
@@ -0,0 +1,254 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 51
+             double_field: 51.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 1101
+             double_field: 1101.0
+             string_field: foo
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 10223372036854778000
+             double_field: 10223372036854778000.0
+             string_field: foo
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+              aggs:
+                the_avg:
+                  avg:
+                    field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.first_filter.the_avg.value: 1101.0 }
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.the_avg.value: 10223372036854778000.0 }
+
+---
+"Anonymous filters test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  - match:
+                      unsigned_field: 1101
+                  - match:
+                      unsigned_field: 10223372036854778000
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.0.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.1.doc_count: 1 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  - match:
+                      unsigned_field: 1101
+                  - match:
+                      unsigned_field: 10223372036854778000
+              aggs:
+                the_avg:
+                  avg:
+                    field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.0.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.0.the_avg.value: 1101.0 }
+  - match: { aggregations.the_filter.buckets.1.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.1.the_avg.value: 10223372036854778000.0 }
+
+---
+"Only aggs test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          size: 0
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 0 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+              aggs:
+                the_avg:
+                  avg:
+                    field: unsigned_field
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.first_filter.the_avg.value: 1101.0 }
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.the_avg.value: 10223372036854778000.0 }
+
+---
+"Filtered test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            constant_score:
+              filter:
+                range:
+                  unsigned_field:
+                    gte: 1110
+          aggs:
+            the_filter:
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+              aggs:
+                the_avg:
+                  avg:
+                    field: unsigned_field
+
+  - match: { hits.total: 1 }
+  - length: { hits.hits: 1 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 0 }
+  - is_false: aggregations.the_filter.buckets.first_filter.the_avg.value
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.the_avg.value: 10223372036854778000.0 }
+
+
+---
+"Metadata test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_filter:
+              meta:
+                foo: bar
+              filters:
+                filters:
+                  first_filter:
+                    match:
+                      unsigned_field: 1101
+                  second_filter:
+                    match:
+                      unsigned_field: 10223372036854778000
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_filter.buckets.first_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.buckets.second_filter.doc_count: 1 }
+  - match: { aggregations.the_filter.meta.foo: "bar" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite.yml
index 2e298441918bc..09278690f5d05 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite.yml
@@ -651,92 +651,6 @@ setup:
                     }
                   ]
 
----
-"Simple Composite aggregation with GeoTile grid":
-  - skip:
-      version: " - 7.4.99"
-      reason: geotile_grid is not supported until 7.5.0
-  - do:
-      search:
-        rest_total_hits_as_int: true
-        index: test
-        body:
-          aggregations:
-            test:
-              composite:
-                sources: [
-                  "geo": {
-                    "geotile_grid": {
-                      "field": "geo_point",
-                      "precision": 12
-                    }
-                  },
-                  {
-                    "kw": {
-                      "terms": {
-                        "field": "keyword"
-                      }
-                    }
-                  }
-                ]
-
-  - match: {hits.total: 6}
-  - length: { aggregations.test.buckets: 4 }
-  - match: { aggregations.test.buckets.0.key.geo: "12/730/1590" }
-  - match: { aggregations.test.buckets.0.key.kw: "foo" }
-  - match: { aggregations.test.buckets.0.doc_count: 1 }
-  - match: { aggregations.test.buckets.1.key.geo: "12/1236/1533" }
-  - match: { aggregations.test.buckets.1.key.kw: "bar" }
-  - match: { aggregations.test.buckets.1.doc_count: 2 }
-  - match: { aggregations.test.buckets.2.key.geo: "12/1236/1533" }
-  - match: { aggregations.test.buckets.2.key.kw: "foo" }
-  - match: { aggregations.test.buckets.2.doc_count: 1 }
-  - match: { aggregations.test.buckets.3.key.geo: "12/2048/0" }
-  - match: { aggregations.test.buckets.3.key.kw: "bar" }
-  - match: { aggregations.test.buckets.3.doc_count: 1 }
-
----
-"Simple Composite aggregation with geotile grid add aggregate after":
-  - skip:
-      version: " - 7.4.99"
-      reason: geotile_grid is not supported until 7.5.0
-  - do:
-      search:
-        index: test
-        body:
-          aggregations:
-            test:
-              composite:
-                sources: [
-                  "geo": {
-                    "geotile_grid": {
-                      "field": "geo_point",
-                      "precision": 12
-                    }
-                  },
-                  {
-                    "kw": {
-                      "terms": {
-                        "field": "keyword"
-                      }
-                    }
-                  }
-                ]
-                after: { "geo": "12/730/1590", "kw": "foo" }
-
-  - match: { hits.total.value: 6 }
-  - match: { hits.total.relation: "eq" }
-  - length: { aggregations.test.buckets: 3 }
-  - match: { aggregations.test.buckets.0.key.geo: "12/1236/1533" }
-  - match: { aggregations.test.buckets.0.key.kw: "bar" }
-  - match: { aggregations.test.buckets.0.doc_count: 2 }
-  - match: { aggregations.test.buckets.1.key.geo: "12/1236/1533" }
-  - match: { aggregations.test.buckets.1.key.kw: "foo" }
-  - match: { aggregations.test.buckets.1.doc_count: 1 }
-  - match: { aggregations.test.buckets.2.key.geo: "12/2048/0" }
-  - match: { aggregations.test.buckets.2.key.kw: "bar" }
-  - match: { aggregations.test.buckets.2.doc_count: 1 }
-
 ---
 "Mixed ip and unmapped fields":
   - skip:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite_unsigned.yml
new file mode 100644
index 0000000000000..75c951d56f2ae
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/230_composite_unsigned.yml
@@ -0,0 +1,348 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+        indices.create:
+          index: test
+          body:
+              mappings:
+                properties:
+                  date:
+                    type: date
+                  keyword:
+                    type: keyword
+                  unsigned_long:
+                    type: unsigned_long
+                  geo_point:
+                    type: geo_point
+                  nested:
+                    type: nested
+                    properties:
+                      nested_unsigned_long:
+                        type: unsigned_long
+
+  - do:
+        indices.create:
+          index: other
+          body:
+            mappings:
+              properties:
+                date:
+                  type: date
+                unsigned_long:
+                  type: unsigned_long
+                nested:
+                  type: nested
+                  properties:
+                    nested_long:
+                      type: long
+
+  - do:
+      index:
+        index: test
+        id:    1
+        body:  { "keyword": "foo", "unsigned_long": [10223372036854775807, 184], "geo_point": "37.2343,-115.8067", "nested": [{"nested_unsigned_long": 10223372036854775807}, {"nested_unsigned_long": 184}] }
+
+  - do:
+      index:
+        index: test
+        id:    2
+        body:  { "keyword": ["foo", "bar"], "geo_point": "41.12,-71.34" }
+
+  - do:
+      index:
+        index: test
+        id:    3
+        body:  { "keyword": "bar", "unsigned_long": [100, 0], "geo_point": "90.0,0.0", "nested": [{"nested_unsigned_long": 184}, {"nested_unsigned_long": 0}] }
+
+  - do:
+      index:
+        index: test
+        id:    4
+        body:  { "keyword": "bar", "unsigned_long": [1000, 0], "geo_point": "41.12,-71.34", "nested": [{"nested_unsigned_long": 1000}, {"nested_unsigned_long": 10223372036854775807}] }
+
+  - do:
+      index:
+        index: test
+        id:    5
+        body:  { "date": "2017-10-20T03:08:45" }
+
+  - do:
+      index:
+        index: test
+        id:    6
+        body:  { "date": "2017-10-21T07:00:00" }
+
+  - do:
+      index:
+        index: other
+        id:    0
+        body:  { "date": "2017-10-20T03:08:45" }
+
+  - do:
+      indices.refresh:
+        index: [test, other]
+
+
+---
+"Nested Composite aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          aggregations:
+            test:
+              composite:
+                sources: [
+                  {
+                    "unsigned_long": {
+                      "terms": {
+                        "field": "unsigned_long"
+                      }
+                    }
+                  },
+                  {
+                    "kw": {
+                      "terms": {
+                        "field": "keyword"
+                      }
+                    }
+                  }
+                ]
+
+  - match: { hits.total: 6 }
+  - length: { aggregations.test.buckets: 5 }
+  - match: { aggregations.test.buckets.0.key.unsigned_long: 0}
+  - match: { aggregations.test.buckets.0.key.kw: "bar" }
+  - match: { aggregations.test.buckets.0.doc_count: 2 }
+  - match: { aggregations.test.buckets.1.key.unsigned_long: 100 }
+  - match: { aggregations.test.buckets.1.key.kw: "bar"}
+  - match: { aggregations.test.buckets.1.doc_count: 1 }
+  - match: { aggregations.test.buckets.2.key.unsigned_long: 184 }
+  - match: { aggregations.test.buckets.2.key.kw: "foo" }
+  - match: { aggregations.test.buckets.2.doc_count: 1 }
+  - match: { aggregations.test.buckets.3.key.unsigned_long: 1000}
+  - match: { aggregations.test.buckets.3.key.kw: "bar" }
+  - match: { aggregations.test.buckets.3.doc_count: 1 }
+  - match: { aggregations.test.buckets.4.key.unsigned_long: 10223372036854775807 }
+  - match: { aggregations.test.buckets.4.key.kw: "foo" }
+  - match: { aggregations.test.buckets.4.doc_count: 1 }
+
+---
+"Aggregate After":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          aggregations:
+            test:
+              composite:
+                sources: [
+                  {
+                    "unsigned_long": {
+                      "terms": {
+                        "field": "unsigned_long"
+                      }
+                    }
+                  },
+                  {
+                    "kw": {
+                      "terms": {
+                        "field": "keyword"
+                      }
+                    }
+                  }
+                ]
+                after: { "unsigned_long": 184, "kw": "foo" }
+
+  - match: { hits.total: 6 }
+  - length: { aggregations.test.buckets: 2 }
+  - match: { aggregations.test.buckets.0.key.unsigned_long: 1000 }
+  - match: { aggregations.test.buckets.0.key.kw: "bar" }
+  - match: { aggregations.test.buckets.0.doc_count: 1 }
+  - match: { aggregations.test.buckets.1.key.unsigned_long: 10223372036854775807 }
+  - match: { aggregations.test.buckets.1.key.kw: "foo" }
+  - match: { aggregations.test.buckets.1.doc_count: 1 }
+
+---
+"Composite aggregation with nested parent":
+  - do:
+        search:
+          rest_total_hits_as_int: true
+          index: test
+          body:
+            aggregations:
+              1:
+                nested:
+                  path: nested
+                aggs:
+                  2:
+                    composite:
+                      sources: [
+                        "nested": {
+                          "terms": {
+                            "field": "nested.nested_unsigned_long"
+                        }
+                      }
+                    ]
+
+  - match: { hits.total: 6 }
+  - length: { aggregations.1.2.buckets: 4 }
+  - match: { aggregations.1.2.buckets.0.key.nested: 0 }
+  - match: { aggregations.1.2.buckets.0.doc_count:  1 }
+  - match: { aggregations.1.2.buckets.1.key.nested: 184 }
+  - match: { aggregations.1.2.buckets.1.doc_count:  2 }
+  - match: { aggregations.1.2.buckets.2.key.nested: 1000 }
+  - match: { aggregations.1.2.buckets.2.doc_count:  1 }
+  - match: { aggregations.1.2.buckets.3.key.nested: 10223372036854775807 }
+  - match: { aggregations.1.2.buckets.3.doc_count:  2 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          aggregations:
+            1:
+              nested:
+                path: nested
+              aggs:
+                2:
+                  composite:
+                    after: { "nested": 184 }
+                    sources: [
+                      "nested": {
+                        "terms": {
+                          "field": "nested.nested_unsigned_long"
+                        }
+                      }
+                    ]
+
+  - match: {hits.total: 6}
+  - length: { aggregations.1.2.buckets: 2 }
+  - match: { aggregations.1.2.buckets.0.key.nested: 1000 }
+  - match: { aggregations.1.2.buckets.0.doc_count:  1 }
+  - match: { aggregations.1.2.buckets.1.key.nested: 10223372036854775807 }
+  - match: { aggregations.1.2.buckets.1.doc_count:  2 }
+
+---
+"Composite aggregation with unmapped field":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: [test, other]
+        body:
+          aggregations:
+            test:
+              composite:
+                sources: [
+                {
+                  "unsigned_long": {
+                    "terms": {
+                      "field": "unsigned_long"
+                    }
+                  }
+                },
+                {
+                  "kw": {
+                    "terms": {
+                      "field": "keyword"
+                    }
+                  }
+                }
+                ]
+
+  - match: {hits.total: 7}
+  - length: { aggregations.test.buckets: 5 }
+  - match: { aggregations.test.buckets.0.key.unsigned_long: 0}
+  - match: { aggregations.test.buckets.0.key.kw: "bar" }
+  - match: { aggregations.test.buckets.0.doc_count: 2 }
+  - match: { aggregations.test.buckets.1.key.unsigned_long: 100 }
+  - match: { aggregations.test.buckets.1.key.kw: "bar"}
+  - match: { aggregations.test.buckets.1.doc_count: 1 }
+  - match: { aggregations.test.buckets.2.key.unsigned_long: 184 }
+  - match: { aggregations.test.buckets.2.key.kw: "foo" }
+  - match: { aggregations.test.buckets.2.doc_count: 1 }
+  - match: { aggregations.test.buckets.3.key.unsigned_long: 1000}
+  - match: { aggregations.test.buckets.3.key.kw: "bar" }
+  - match: { aggregations.test.buckets.3.doc_count: 1 }
+  - match: { aggregations.test.buckets.4.key.unsigned_long: 10223372036854775807 }
+  - match: { aggregations.test.buckets.4.key.kw: "foo" }
+  - match: { aggregations.test.buckets.4.doc_count: 1 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: [test, other]
+        body:
+          aggregations:
+            test:
+              composite:
+                after: { "unsigned_long": 1000, "kw": "bar" }
+                sources: [
+                {
+                  "unsigned_long": {
+                    "terms": {
+                      "field": "unsigned_long"
+                    }
+                  }
+                },
+                {
+                  "kw": {
+                    "terms": {
+                      "field": "keyword"
+                    }
+                  }
+                }
+                ]
+
+  - match: {hits.total: 7}
+  - length: { aggregations.test.buckets: 1 }
+  - match: { aggregations.test.buckets.0.key.unsigned_long: 10223372036854775807 }
+  - match: { aggregations.test.buckets.0.key.kw: "foo" }
+  - match: { aggregations.test.buckets.0.doc_count: 1 }
+
+---
+"Terms source from sorted":
+  - do:
+        indices.create:
+          index: sorted_test
+          body:
+              settings:
+                sort.field: keyword
+              mappings:
+                properties:
+                  keyword:
+                    type: keyword
+                  unsigned_long:
+                    type: unsigned_long
+
+
+  - do:
+      index:
+        index:   sorted_test
+        id:      2
+        refresh: true
+        body:  { "keyword": "foo", "unsigned_long": 1 }
+
+  - do:
+      search:
+        index: sorted_test
+        rest_total_hits_as_int: true
+        body:
+          aggregations:
+            test:
+              composite:
+                sources:
+                  - keyword:
+                      terms:
+                        field: keyword
+
+  - match: { hits.total: 1 }
+  - length: { aggregations.test.buckets: 1 }
+  - match: { aggregations.test.buckets.0.key.keyword: "foo" }
+  - match: { aggregations.test.buckets.0.doc_count: 1 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/240_max_buckets.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/240_max_buckets.yml
index 82965bda51576..c540814a1690d 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/240_max_buckets.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/240_max_buckets.yml
@@ -118,4 +118,3 @@ setup:
                 2:
                   terms:
                     field: date
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/250_moving_fn.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/250_moving_fn.yml
index 339fe72b77730..c0a8d2fb4500c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/250_moving_fn.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/250_moving_fn.yml
@@ -74,4 +74,3 @@
                 buckets_path: "the_avg"
                 window: -1
                 script: "MovingFunctions.windowMax(values)"
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/260_weighted_avg_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/260_weighted_avg_unsigned.yml
new file mode 100644
index 0000000000000..5cdf7726e7230
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/260_weighted_avg_unsigned.yml
@@ -0,0 +1,70 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test_1
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                unsigned_field:
+                   type : unsigned_long
+                double_field:
+                   type : double
+                string_field:
+                   type: keyword
+
+  - do:
+       bulk:
+         refresh: true
+         body:
+           - index:
+               _index: test_1
+               _id:    1
+           - unsigned_field: 1
+             double_field: 1.0
+           - index:
+               _index: test_1
+               _id:    2
+           - unsigned_field: 2
+             double_field: 2.0
+           - index:
+               _index: test_1
+               _id:    3
+           - unsigned_field: 3
+             double_field: 3.0
+           - index:
+               _index: test_1
+               _id:    4
+           - unsigned_field: 4
+             double_field: 4.0
+
+---
+"Basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            the_unsigned_avg:
+              weighted_avg:
+                value:
+                  field: "unsigned_field"
+                weight:
+                  field: "unsigned_field"
+            the_double_avg:
+              weighted_avg:
+                value:
+                  field: "double_field"
+                weight:
+                  field: "double_field"
+
+  - match: { hits.total: 4 }
+  - length: { hits.hits: 4 }
+  - match: { aggregations.the_unsigned_avg.value: 3.0 }
+  - match: { aggregations.the_double_avg.value: 3.0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/270_median_absolute_deviation_metric_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/270_median_absolute_deviation_metric_unsigned.yml
new file mode 100644
index 0000000000000..289b61c9c8783
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/270_median_absolute_deviation_metric_unsigned.yml
@@ -0,0 +1,121 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+        indices.create:
+            index: test
+            body:
+              settings:
+                number_of_replicas: 0
+              mappings:
+                properties:
+                  unsigned_field:
+                    type: unsigned_long
+                  double_field:
+                    type: double
+                  incomplete_field:
+                    type: integer
+  - do:
+        bulk:
+          refresh: true
+          body:
+            - index:
+                _index: test
+            - unsigned_field: 10223372036700000000
+              double_field: 10223372036700000000
+              incomplete_field: 1000
+            - index:
+                _index: test
+            - unsigned_field: 10223372036800000000
+              double_field: 10223372036800000000
+              incomplete_field: 2000
+            - index:
+                _index: test
+            - unsigned_field: 10223372036900000000
+              double_field: 10223372036900000000.0
+
+---
+"basic test":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            mad_unsigned:
+              median_absolute_deviation:
+                field: unsigned_field
+            mad_double:
+              median_absolute_deviation:
+                field: double_field
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+
+  - match: { aggregations.mad_unsigned.value: 99999744 }
+  - match: { aggregations.mad_double.value: 99999744.0 }
+
+---
+"with setting compression":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            mad_unsigned:
+              median_absolute_deviation:
+                field: unsigned_field
+                compression: 500
+            mad_double:
+              median_absolute_deviation:
+                field: double_field
+                compression: 500
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+
+  - match: { aggregations.mad_unsigned.value: 99999744 }
+  - match: { aggregations.mad_double.value: 99999744.0 }
+
+---
+"no documents":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query:
+            bool:
+              filter:
+                term:
+                  non_existent_field: non_existent_value
+          aggs:
+            mad_no_docs:
+              median_absolute_deviation:
+                field: non_existent_field
+
+  - match: { hits.total: 0 }
+  - length: { hits.hits: 0 }
+
+  - match: { aggregations.mad_no_docs.value: null }
+
+---
+"missing value":
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          aggs:
+            mad_missing:
+              median_absolute_deviation:
+                field: incomplete_field
+                missing: 30000000000000000000
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+
+  - match: { aggregations.mad_missing.value: 1000 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/350_variable_width_histogram.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/350_variable_width_histogram.yml
index 071e543e8a25e..cc41ef1fa6cd3 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/350_variable_width_histogram.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/350_variable_width_histogram.yml
@@ -47,4 +47,3 @@ setup:
   - match: { aggregations.histo.buckets.1.doc_count: 1 }
   - match: { aggregations.histo.buckets.2.key: 4.5 }
   - match: { aggregations.histo.buckets.2.doc_count: 2 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/370_multi_terms.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/370_multi_terms.yml
new file mode 100644
index 0000000000000..7db5f31d8e761
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/370_multi_terms.yml
@@ -0,0 +1,762 @@
+setup:
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          settings:
+            number_of_shards: 1
+            number_of_replicas: 0
+          mappings:
+            properties:
+              str:
+                type: keyword
+              ip:
+                type: ip
+              boolean:
+                type: boolean
+              integer:
+                type: long
+              double:
+                type: double
+              number:
+                type: long
+              date:
+                type: date
+
+  - do:
+      indices.create:
+        index: test_2
+        body:
+          settings:
+            number_of_shards: 2
+            number_of_replicas: 0
+          mappings:
+            properties:
+              str:
+                type: keyword
+              integer:
+                type: long
+              boolean:
+                type: boolean
+
+  - do:
+      cluster.health:
+        wait_for_status: green
+
+---
+"Basic test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: integer
+
+  - length: { aggregations.m_terms.buckets: 4 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", 1] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|1" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.2.key: ["a", 2] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "a|2" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.3.key: ["b", 2] }
+  - match: { aggregations.m_terms.buckets.3.key_as_string: "b|2" }
+  - match: { aggregations.m_terms.buckets.3.doc_count: 1 }
+
+---
+"IP test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "ip": "::1"}'
+          - '{"index": {}}'
+          - '{"str": "a", "ip": "127.0.0.1"}'
+          - '{"index": {}}'
+          - '{"str": "b", "ip": "::1"}'
+          - '{"index": {}}'
+          - '{"str": "b", "ip": "127.0.0.1"}'
+          - '{"index": {}}'
+          - '{"str": "a", "ip": "127.0.0.1"}'
+          - '{"index": {}}'
+          - '{"str": "b", "ip": "::1"}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: ip
+
+  - length: { aggregations.m_terms.buckets: 4 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", "127.0.0.1"] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|127.0.0.1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", "::1"] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|::1" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.2.key: ["a", "::1"] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "a|::1" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.3.key: ["b", "127.0.0.1"] }
+  - match: { aggregations.m_terms.buckets.3.key_as_string: "b|127.0.0.1" }
+  - match: { aggregations.m_terms.buckets.3.doc_count: 1 }
+
+---
+"Boolean test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "boolean": true}'
+          - '{"index": {}}'
+          - '{"str": "a", "boolean": false}'
+          - '{"index": {}}'
+          - '{"str": "b", "boolean": false}'
+          - '{"index": {}}'
+          - '{"str": "b", "boolean": true}'
+          - '{"index": {}}'
+          - '{"str": "a", "boolean": true}'
+          - '{"index": {}}'
+          - '{"str": "b", "boolean": false}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: boolean
+
+  - length: { aggregations.m_terms.buckets: 4 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", true] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|true" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", false] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|false" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.2.key: ["a", false] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "a|false" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.3.key: ["b", true] }
+  - match: { aggregations.m_terms.buckets.3.key_as_string: "b|true" }
+  - match: { aggregations.m_terms.buckets.3.doc_count: 1 }
+
+---
+"Long test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "number": 4611686018427387903}'
+          - '{"index": {}}'
+          - '{"str": "a", "number": -4611686018427387904}'
+          - '{"index": {}}'
+          - '{"str": "b", "number": 4611686018427387903}'
+          - '{"index": {}}'
+          - '{"str": "a", "number": 4611686018427387903}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: number
+
+  - length: { aggregations.m_terms.buckets: 3 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 4611686018427387903] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|4611686018427387903" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["a", -4611686018427387904] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "a|-4611686018427387904" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.2.key: ["b", 4611686018427387903] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "b|4611686018427387903" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+
+---
+"Unsigned Long test":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.put_mapping:
+        index: test_1
+        body:
+          properties:
+            unsigned:
+              type: unsigned_long
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "unsigned": 18446744073709551615}'
+          - '{"index": {}}'
+          - '{"str": "a", "unsigned": 10223372036854775807}'
+          - '{"index": {}}'
+          - '{"str": "b", "unsigned": 18446744073709551615}'
+          - '{"index": {}}'
+          - '{"str": "a", "unsigned": 18446744073709551615}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: unsigned
+
+  - length: { aggregations.m_terms.buckets: 3 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 18446744073709551615] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|18446744073709551615" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["a", 10223372036854775807] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "a|10223372036854775807" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.2.key: ["b", 18446744073709551615] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "b|18446744073709551615" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+
+---
+"Double test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5}'
+          - '{"index": {}}'
+          - '{"str": "a", "double": 5678.5}'
+          - '{"index": {}}'
+          - '{"str": "b", "double": 1234.5}'
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: double
+
+  - length: { aggregations.m_terms.buckets: 3 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1234.5] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1234.5" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["a", 5678.5] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "a|5678.5" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.2.key: ["b", 1234.5] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "b|1234.5" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+
+---
+"Date test":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "date": "2022-03-23"}'
+          - '{"index": {}}'
+          - '{"str": "a", "date": "2022-03-25"}'
+          - '{"index": {}}'
+          - '{"str": "b", "date": "2022-03-23"}'
+          - '{"index": {}}'
+          - '{"str": "a", "date": "2022-03-23"}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: date
+
+  - length: { aggregations.m_terms.buckets: 3 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", "2022-03-23T00:00:00.000Z"] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|2022-03-23T00:00:00.000Z" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["a", "2022-03-25T00:00:00.000Z"] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "a|2022-03-25T00:00:00.000Z" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.2.key: ["b", "2022-03-23T00:00:00.000Z"] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "b|2022-03-23T00:00:00.000Z" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 1 }
+
+---
+"Unmapped keywords":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: unmapped_string
+                    value_type: string
+                    missing: abc
+
+  - length: { aggregations.m_terms.buckets: 2 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", "abc"] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|abc" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", "abc"] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|abc" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+
+---
+"Null value":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "integer": null}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": null, "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: integer
+
+  - length: { aggregations.m_terms.buckets: 1 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 2] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|2" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 1 }
+
+---
+"multiple multi_terms bucket":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1, "double": 1234.5, "boolean": true}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1, "double": 5678.9, "boolean": false}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1, "double": 1234.5, "boolean": true}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 1, "double": 1234.5, "boolean": true}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: integer
+              aggs:
+                n_terms:
+                  multi_terms:
+                    terms:
+                      - field: double
+                      - field: boolean
+
+  - length: { aggregations.m_terms.buckets: 2 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 3 }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.0.key: [1234.5, true] }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.0.key_as_string: "1234.5|true" }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.1.key: [5678.9, false] }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.1.key_as_string: "5678.9|false" }
+  - match: { aggregations.m_terms.buckets.0.n_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", 1] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|1" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+
+---
+"ordered by metrics":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5, "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "b", "double": 5678.9, "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "b", "double": 5678.9, "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5, "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: double
+                order:
+                  the_int_sum: desc
+              aggs:
+                the_int_sum:
+                  sum:
+                    field: integer
+
+  - length: { aggregations.m_terms.buckets: 2 }
+  - match: { aggregations.m_terms.buckets.0.key: ["b", 5678.9] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "b|5678.9" }
+  - match: { aggregations.m_terms.buckets.0.the_int_sum.value: 4.0 }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["a", 1234.5] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "a|1234.5" }
+  - match: { aggregations.m_terms.buckets.1.the_int_sum.value: 2.0 }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 2 }
+
+---
+"top 1 ordered by metrics ":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5, "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "b", "double": 5678.9, "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "b", "double": 5678.9, "integer": 2}'
+          - '{"index": {}}'
+          - '{"str": "a", "double": 1234.5, "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: double
+                order:
+                  the_int_sum: desc
+                size: 1
+              aggs:
+                the_int_sum:
+                  sum:
+                    field: integer
+
+  - length: { aggregations.m_terms.buckets: 1 }
+  - match: { aggregations.m_terms.buckets.0.key: ["b", 5678.9] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "b|5678.9" }
+  - match: { aggregations.m_terms.buckets.0.the_int_sum.value: 4.0 }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+
+---
+"min_doc_count":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "b", "integer": 1}'
+          - '{"index": {}}'
+          - '{"str": "c", "integer": 1}'
+
+  - do:
+      search:
+        index: test_1
+        body:
+          size: 0
+          query:
+            simple_query_string:
+              fields: [str]
+              query: a b
+              minimum_should_match: 1
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: integer
+                min_doc_count: 2
+
+  - length: { aggregations.m_terms.buckets: 1 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+
+  - do:
+      search:
+        index: test_1
+        body:
+          size: 0
+          query:
+            simple_query_string:
+              fields: [str]
+              query: a b
+              minimum_should_match: 1
+          aggs:
+            m_terms:
+              multi_terms:
+                terms:
+                  - field: str
+                  - field: integer
+                min_doc_count: 0
+
+  - length: { aggregations.m_terms.buckets: 3 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 2 }
+  - match: { aggregations.m_terms.buckets.1.key: ["b", 1] }
+  - match: { aggregations.m_terms.buckets.1.key_as_string: "b|1" }
+  - match: { aggregations.m_terms.buckets.1.doc_count: 1 }
+  - match: { aggregations.m_terms.buckets.2.key: ["c", 1] }
+  - match: { aggregations.m_terms.buckets.2.key_as_string: "c|1" }
+  - match: { aggregations.m_terms.buckets.2.doc_count: 0 }
+
+---
+"sum_other_doc_count":
+  - skip:
+      version: "- 2.0.99"
+      reason:  multi_terms aggregation is introduced in 2.1.0
+
+  - do:
+      bulk:
+        index: test_2
+        refresh: true
+        body:
+          - '{"index": {"routing": "s1"}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {"routing": "s1"}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {"routing": "s1"}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {"routing": "s1"}}'
+          - '{"str": "a", "integer": 1}'
+          - '{"index": {"routing": "s2"}}'
+          - '{"str": "b", "integer": 1}'
+          - '{"index": {"routing": "s2"}}'
+          - '{"str": "b", "integer": 1}'
+          - '{"index": {"routing": "s2"}}'
+          - '{"str": "b", "integer": 1}'
+          - '{"index": {"routing": "s2"}}'
+          - '{"str": "a", "integer": 1}'
+
+  - do:
+      search:
+        index: test_2
+        size: 0
+        body:
+          aggs:
+            m_terms:
+              multi_terms:
+                size: 1
+                shard_size: 1
+                terms:
+                  - field: str
+                  - field: integer
+
+  - length: { aggregations.m_terms.buckets: 1 }
+  - match: { aggregations.m_terms.sum_other_doc_count: 4 }
+  - match: { aggregations.m_terms.buckets.0.key: ["a", 1] }
+  - match: { aggregations.m_terms.buckets.0.key_as_string: "a|1" }
+  - match: { aggregations.m_terms.buckets.0.doc_count: 4 }
+
+---
+"aggregate over multi-terms test":
+  - skip:
+      version: "- 2.8.99"
+      reason: "multi_terms aggregation was introduced in 2.1.0, NPE bug checked by this test case will manifest in any version < 3.0"
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"str": "a", "ip": "127.0.0.1", "date": "2022-03-23"}'
+          - '{"index": {}}'
+          - '{"str": "a", "ip": "127.0.0.1", "date": "2022-03-25"}'
+          - '{"index": {}}'
+          - '{"str": "b", "ip": "127.0.0.1", "date": "2022-03-23"}'
+          - '{"index": {}}'
+          - '{"str": "b", "ip": "127.0.0.1", "date": "2022-03-25"}'
+
+  - do:
+      search:
+        index: test_1
+        size: 0
+        body:
+          aggs:
+            histo:
+              date_histogram:
+                field: date
+                calendar_interval: day
+              aggs:
+                m_terms:
+                  multi_terms:
+                    terms:
+                      - field: str
+                      - field: ip
+
+  - match: { hits.total.value: 4 }
+  - length: { aggregations.histo.buckets: 3 }
+  - match: { aggregations.histo.buckets.0.key_as_string: "2022-03-23T00:00:00.000Z" }
+  - match: { aggregations.histo.buckets.0.m_terms.buckets.0.key: ["a", "127.0.0.1"] }
+  - match: { aggregations.histo.buckets.0.m_terms.buckets.1.key: ["b", "127.0.0.1"] }
+  - match: { aggregations.histo.buckets.1.key_as_string: "2022-03-24T00:00:00.000Z" }
+  - length: { aggregations.histo.buckets.1.m_terms.buckets: 0 }
+  - match: { aggregations.histo.buckets.2.key_as_string: "2022-03-25T00:00:00.000Z" }
+  - match: { aggregations.histo.buckets.2.m_terms.buckets.0.key: [ "a", "127.0.0.1" ] }
+  - match: { aggregations.histo.buckets.2.m_terms.buckets.1.key: [ "b", "127.0.0.1" ] }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/380_doc_count_field.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/380_doc_count_field.yml
new file mode 100644
index 0000000000000..a7a796eceeb39
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/380_doc_count_field.yml
@@ -0,0 +1,146 @@
+setup:
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          settings:
+            number_of_replicas: 0
+          mappings:
+            properties:
+              str:
+                type: keyword
+              number:
+                type: integer
+
+  - do:
+      bulk:
+        index: test_1
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"_doc_count": 10, "str": "abc", "number" : 500, "unmapped": "abc" }'
+          - '{"index": {}}'
+          - '{"_doc_count": 5, "str": "xyz", "number" : 100, "unmapped": "xyz" }'
+          - '{"index": {}}'
+          - '{"_doc_count": 7, "str": "foo", "number" : 100, "unmapped": "foo" }'
+          - '{"index": {}}'
+          - '{"_doc_count": 1, "str": "foo", "number" : 200, "unmapped": "foo" }'
+          - '{"index": {}}'
+          - '{"str": "abc", "number" : 500, "unmapped": "abc" }'
+
+---
+"Test numeric terms agg with doc_count":
+  - skip:
+      version: "1.0.0 - "
+      reason: "until this is released and we know exact version"
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "num_terms" : { "terms" : { "field" : "number" } } } }
+
+  - match: { hits.total: 5 }
+  - length: { aggregations.num_terms.buckets: 3 }
+  - match: { aggregations.num_terms.buckets.0.key: 100 }
+  - match: { aggregations.num_terms.buckets.0.doc_count: 12 }
+  - match: { aggregations.num_terms.buckets.1.key: 500 }
+  - match: { aggregations.num_terms.buckets.1.doc_count: 11 }
+  - match: { aggregations.num_terms.buckets.2.key: 200 }
+  - match: { aggregations.num_terms.buckets.2.doc_count: 1 }
+
+---
+"Test keyword terms agg with doc_count":
+  - skip:
+      version: "1.0.0 - "
+      reason: "until this is released and we know exact version"
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "str_terms" : { "terms" : { "field" : "str" } } } }
+
+  - match: { hits.total: 5 }
+  - length: { aggregations.str_terms.buckets: 3 }
+  - match: { aggregations.str_terms.buckets.0.key: "abc" }
+  - match: { aggregations.str_terms.buckets.0.doc_count: 11 }
+  - match: { aggregations.str_terms.buckets.1.key: "foo" }
+  - match: { aggregations.str_terms.buckets.1.doc_count: 8 }
+  - match: { aggregations.str_terms.buckets.2.key: "xyz" }
+  - match: { aggregations.str_terms.buckets.2.doc_count: 5 }
+
+---
+"Test unmapped string terms agg with doc_count":
+  - skip:
+      version: "1.0.0 - "
+      reason: "until this is released and we know exact version"
+  - do:
+      bulk:
+        index: test_2
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"_doc_count": 10, "str": "abc" }'
+          - '{"index": {}}'
+          - '{"str": "abc" }'
+  - do:
+      search:
+        index: test_2
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "str_terms" : { "terms" : { "field" : "str.keyword" } } } }
+
+  - match: { hits.total: 2 }
+  - length: { aggregations.str_terms.buckets: 1 }
+  - match: { aggregations.str_terms.buckets.0.key: "abc" }
+  - match: { aggregations.str_terms.buckets.0.doc_count: 11 }
+
+---
+"Test composite str_terms agg with doc_count":
+  - skip:
+      version: "1.0.0 - "
+      reason: "until this is released and we know exact version"
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" :
+          { "composite_agg" : { "composite" :
+                                  {
+                                    "sources": ["str_terms": { "terms": { "field": "str" } }]
+                                  }
+          }
+          }
+        }
+
+  - match: { hits.total: 5 }
+  - length: { aggregations.composite_agg.buckets: 3 }
+  - match: { aggregations.composite_agg.buckets.0.key.str_terms: "abc" }
+  - match: { aggregations.composite_agg.buckets.0.doc_count: 11 }
+  - match: { aggregations.composite_agg.buckets.1.key.str_terms: "foo" }
+  - match: { aggregations.composite_agg.buckets.1.doc_count: 8 }
+  - match: { aggregations.composite_agg.buckets.2.key.str_terms: "xyz" }
+  - match: { aggregations.composite_agg.buckets.2.doc_count: 5 }
+
+---
+"Test composite num_terms agg with doc_count":
+  - skip:
+      version: "1.0.0 - "
+      reason: "until this is released and we know exact version"
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" :
+          { "composite_agg" :
+              { "composite" :
+                  {
+                    "sources": ["num_terms" : { "terms" : { "field" : "number" } }]
+                  }
+              }
+          }
+        }
+
+  - match: { hits.total: 5 }
+  - length: { aggregations.composite_agg.buckets: 3 }
+  - match: { aggregations.composite_agg.buckets.0.key.num_terms: 100 }
+  - match: { aggregations.composite_agg.buckets.0.doc_count: 12 }
+  - match: { aggregations.composite_agg.buckets.1.key.num_terms: 200 }
+  - match: { aggregations.composite_agg.buckets.1.doc_count: 1 }
+  - match: { aggregations.composite_agg.buckets.2.key.num_terms: 500 }
+  - match: { aggregations.composite_agg.buckets.2.doc_count: 11 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/40_range.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/40_range.yml
index a050b4c5bbf11..7d887d56ae8fe 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/40_range.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/40_range.yml
@@ -427,3 +427,104 @@ setup:
   - match: { aggregations.date_range.buckets.0.key: "2020-01-01T00:00:00.000Z-*" }
   - is_false: aggregations.date_range.buckets.0.to
   - match: { aggregations.date_range.buckets.0.sounds.value: 0 }
+
+---
+"Unsigned long range":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.put_mapping:
+        index: test
+        body:
+          properties:
+            unsigned:
+              type: unsigned_long
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: { "unsigned" : 42 }
+
+  - do:
+      index:
+        index: test
+        id: 2
+        body: { "unsigned" : 100 }
+
+  - do:
+      index:
+        index: test
+        id: 3
+        body: { "unsigned" : 50 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "unsigned_long_range" : { "range" : { "field" : "unsigned", "ranges": [ { "to": 50 }, { "from": 50, "to": 150 }, { "from": 150 } ] } } } }
+
+  - match: { hits.total: 3 }
+
+  - length: { aggregations.unsigned_long_range.buckets: 3 }
+
+  - match: { aggregations.unsigned_long_range.buckets.0.key: "*-50.0" }
+
+  - is_false: aggregations.unsigned_long_range.buckets.0.from
+
+  - match: { aggregations.unsigned_long_range.buckets.0.to: 50.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.0.doc_count: 1 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.key: "50.0-150.0" }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.from: 50.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.to: 150.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.doc_count: 2 }
+
+  - match: { aggregations.unsigned_long_range.buckets.2.key: "150.0-*" }
+
+  - match: { aggregations.unsigned_long_range.buckets.2.from: 150.0 }
+
+  - is_false:  aggregations.unsigned_long_range.buckets.2.to
+
+  - match: { aggregations.unsigned_long_range.buckets.2.doc_count: 0 }
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { "unsigned_long_range" : { "range" : { "field" : "unsigned", "ranges": [ { "from": null, "to": 50 }, { "from": 50, "to": 150 }, { "from": 150, "to": null } ] } } } }
+
+  - match: { hits.total: 3 }
+
+  - length: { aggregations.unsigned_long_range.buckets: 3 }
+
+  - match: { aggregations.unsigned_long_range.buckets.0.key: "*-50.0" }
+
+  - is_false: aggregations.unsigned_long_range.buckets.0.from
+
+  - match: { aggregations.unsigned_long_range.buckets.0.to: 50.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.0.doc_count: 1 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.key: "50.0-150.0" }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.from: 50.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.to: 150.0 }
+
+  - match: { aggregations.unsigned_long_range.buckets.1.doc_count: 2 }
+
+  - match: { aggregations.unsigned_long_range.buckets.2.key: "150.0-*" }
+
+  - match: { aggregations.unsigned_long_range.buckets.2.from: 150.0 }
+
+  - is_false:  aggregations.unsigned_long_range.buckets.2.to
+
+  - match: { aggregations.unsigned_long_range.buckets.2.doc_count: 0 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/60_empty.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/60_empty.yml
new file mode 100644
index 0000000000000..54f61d46b6f6c
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/60_empty.yml
@@ -0,0 +1,32 @@
+---
+"Empty aggs Body":
+  - skip:
+      version: "- 2.8.99"
+      reason: "the fix was introduced in 2.9.0"
+  - do:
+      index:
+        index: test
+        id: 1
+        body: { "double" : 42 }
+
+  - do:
+      index:
+        index: test
+        id: 2
+        body: { "double" : 100 }
+
+  - do:
+      index:
+        index: test
+        id: 3
+        body: { "double" : 50 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body: { "size" : 0, "aggs" : { } }
+
+  - match: { hits.total: 3 }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/80_typed_keys_unsigned.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/80_typed_keys_unsigned.yml
new file mode 100644
index 0000000000000..5ae912a92d8c8
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/80_typed_keys_unsigned.yml
@@ -0,0 +1,237 @@
+setup:
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+          index: test
+          body:
+            settings:
+              number_of_replicas: 0
+            mappings:
+              properties:
+                name:
+                   type: keyword
+                num:
+                   type: unsigned_long
+                created:
+                  type: date
+
+  - do:
+     bulk:
+        refresh: true
+        index: test
+        body:
+          - '{"index": {}}'
+          - '{"name": "one", "num": 1, "created": "2010-03-12T01:07:45"}'
+          - '{"index": {}}'
+          - '{"name": "two", "num": 2, "created": "2010-03-12T04:11:00"}'
+          - '{"index": {}}'
+          - '{"name": "three", "num": 3, "created": "2010-04-27T03:43:34"}'
+
+---
+"Test typed keys parameter for avg aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_avg:
+              avg:
+                field: num
+  - is_true: aggregations.avg#test_avg
+
+---
+"Test typed keys parameter for cardinality aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_cardinality:
+              cardinality:
+                field: name
+  - is_true: aggregations.cardinality#test_cardinality
+
+---
+"Test typed keys parameter for extended_stats aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_extended_stats:
+              extended_stats:
+                field: num
+  - is_true: aggregations.extended_stats#test_extended_stats
+
+---
+"Test typed keys parameter for max aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_max:
+              max:
+                field: num
+  - is_true: aggregations.max#test_max
+
+---
+"Test typed keys parameter for min aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_min:
+              min:
+                field: num
+  - is_true: aggregations.min#test_min
+
+---
+"Test typed keys parameter for percentiles aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_percentiles:
+              percentiles:
+                field: num
+  - is_true: aggregations.tdigest_percentiles#test_percentiles
+
+---
+"Test typed keys parameter for percentile_ranks aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_percentile_ranks:
+              percentile_ranks:
+                field: num
+                values: [0,10]
+  - is_true: aggregations.tdigest_percentile_ranks#test_percentile_ranks
+
+---
+"Test typed keys parameter for stats aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_stats:
+              stats:
+                field: num
+  - is_true: aggregations.stats#test_stats
+
+---
+"Test typed keys parameter for sum aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_sum:
+              sum:
+                field: num
+  - is_true: aggregations.sum#test_sum
+
+---
+"Test typed keys parameter for terms and top_hits aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_terms:
+              terms:
+                field: name
+              aggs:
+                test_top_hits:
+                  top_hits:
+                    sort: num
+  - is_true: aggregations.sterms#test_terms
+  - is_true: aggregations.sterms#test_terms.buckets.0.top_hits#test_top_hits
+  - is_true: aggregations.sterms#test_terms.buckets.1.top_hits#test_top_hits
+  - is_true: aggregations.sterms#test_terms.buckets.2.top_hits#test_top_hits
+
+---
+"Test typed keys parameter for terms aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_terms:
+              terms:
+                field: num
+  - is_true: aggregations.ulterms#test_terms
+
+---
+"Test typed keys parameter for value_count aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_value_count:
+              value_count:
+                field: num
+  - is_true: aggregations.value_count#test_value_count
+
+---
+"Test typed keys parameter for date_histogram aggregation and max_bucket pipeline aggregation":
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        typed_keys: true
+        body:
+          size: 0
+          aggregations:
+            test_created_histogram:
+              date_histogram:
+                field: created
+                calendar_interval: month
+              aggregations:
+                test_sum:
+                  sum:
+                    field: num
+                test_deriv:
+                  derivative:
+                    buckets_path: "test_sum"
+            test_max_bucket:
+              max_bucket:
+                buckets_path: "test_created_histogram>test_sum"
+
+  - is_true: aggregations.date_histogram#test_created_histogram
+  - is_true: aggregations.date_histogram#test_created_histogram.buckets.0.sum#test_sum
+  - is_true: aggregations.date_histogram#test_created_histogram.buckets.1.sum#test_sum
+  - is_true: aggregations.date_histogram#test_created_histogram.buckets.1.derivative#test_deriv
+  - is_true: aggregations.bucket_metric_value#test_max_bucket
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.highlight/30_max_analyzed_offset.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.highlight/30_max_analyzed_offset.yml
index 462f4f5d25e0b..a18ac45e62175 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.highlight/30_max_analyzed_offset.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.highlight/30_max_analyzed_offset.yml
@@ -36,6 +36,17 @@ setup:
           body: {"query" : {"match" : {"field1" : "fox"}}, "highlight" : {"type" : "unified", "fields" : {"field1" : {}}}}
   - match: { error.root_cause.0.type: "illegal_argument_exception" }
 
+---
+"Unified highlighter on a field WITHOUT OFFSETS using max_analyzer_offset should SUCCEED":
+  - skip:
+        version: " - 2.1.99"
+        reason: only starting supporting the parameter max_analyzer_offset on version 2.2
+  - do:
+      search:
+          rest_total_hits_as_int: true
+          index: test1
+          body: {"query" : {"match" : {"field1" : "quick"}}, "highlight" : {"type" : "unified", "fields" : {"field1" : {"max_analyzer_offset": 10}}}}
+  - match: {hits.hits.0.highlight.field1.0: "The <em>quick</em> brown fox went to the forest and saw another fox."}
 
 ---
 "Plain highlighter on a field WITHOUT OFFSETS exceeding index.highlight.max_analyzed_offset should FAIL":
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/10_source_filtering.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/10_source_filtering.yml
index 091638d6a07fb..4de2e8142f6ec 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/10_source_filtering.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/10_source_filtering.yml
@@ -196,4 +196,3 @@ setup:
   # When this test is run during runtime-field's tests we *don't* get floating point errors. Thus the funny assertion here that matches both.
   - lt: { hits.hits.0.fields.d.0: 3.141 }
   - gte: { hits.hits.0.fields.d.0: 3.14 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/110_field_collapsing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/110_field_collapsing.yml
index 149bc90f31ea0..78134336ea45e 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/110_field_collapsing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/110_field_collapsing.yml
@@ -254,6 +254,7 @@ setup:
   - do:
       catch:      /cannot use \`collapse\` in conjunction with \`search_after\`/
       search:
+        allow_partial_search_results: false
         rest_total_hits_as_int: true
         index: test
         body:
@@ -267,6 +268,7 @@ setup:
   - do:
       catch:      /cannot use \`collapse\` in conjunction with \`rescore\`/
       search:
+        allow_partial_search_results: false
         rest_total_hits_as_int: true
         index: test
         body:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/140_pre_filter_search_shards.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/140_pre_filter_search_shards.yml
index 31f6f35003e2d..40e1fbcf7a2ab 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/140_pre_filter_search_shards.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/140_pre_filter_search_shards.yml
@@ -154,4 +154,3 @@ setup:
   - match: { _shards.failed: 0 }
   - match: { hits.total: 2 }
   - length: { aggregations.idx_terms.buckets: 2 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/160_exists_query.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/160_exists_query.yml
index 201e456be2cdd..be97930d41eb9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/160_exists_query.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/160_exists_query.yml
@@ -561,19 +561,6 @@ setup:
 
   - match: {hits.total: 4}
 
----
-"Test exists query on _type field":
-  - do:
-      search:
-          rest_total_hits_as_int: true
-          index: test
-          body:
-            query:
-              exists:
-                field: _type
-
-  - match: {hits.total: 4}
-
 ---
 "Test exists query on _routing field":
   - do:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/190_index_prefix_search.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/190_index_prefix_search.yml
index 6f276f669f815..4532a26451c05 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/190_index_prefix_search.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/190_index_prefix_search.yml
@@ -17,6 +17,12 @@ setup:
           id:     1
           body:   { text: some short words with a stupendously long one }
 
+  - do:
+      index:
+        index:  test
+        id:     2
+        body:   { text: sentence with UPPERCASE WORDS }
+
   - do:
       indices.refresh:
         index: [test]
@@ -76,6 +82,25 @@ setup:
   - match: {hits.max_score: 1}
   - match: {hits.hits.0._score: 1}
 
+---
+"search with uppercase regex":
+  - skip:
+      version: " - 2.3.99"
+      reason: uppercase regex not supported before 2.4.0
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        index: test
+        body:
+          query:
+            query_string:
+              default_field: text
+              query: /UPPERCASE/
+
+  - match: {hits.total: 1}
+  - match: {hits.max_score: 1}
+  - match: {hits.hits.0._score: 1}
+
 ---
 "search index prefixes with span_multi":
   - do:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/230_interval_query.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/230_interval_query.yml
index 0286d3caf66b8..0b9172e0740ea 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/230_interval_query.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/230_interval_query.yml
@@ -750,5 +750,3 @@ setup:
                     - prefix:
                         prefix: out
   - match: { hits.total.value: 3 }
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/240_date_nanos.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/240_date_nanos.yml
index feb875e81a785..1ddba45c97c72 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/240_date_nanos.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/240_date_nanos.yml
@@ -164,4 +164,3 @@ setup:
   - match: { aggregations.date.buckets.1.key: 1540857600000 }
   - match: { aggregations.date.buckets.1.key_as_string: "2018-10-30T00:00:00.000Z" }
   - match: { aggregations.date.buckets.1.doc_count: 2 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/260_sort_mixed.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/260_sort_mixed.yml
new file mode 100644
index 0000000000000..ba2b18eb3b6d0
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/260_sort_mixed.yml
@@ -0,0 +1,121 @@
+"search across indices with mixed long and double numeric types":
+  - skip:
+      version: " - 2.6.99"
+      reason: relies on numeric sort optimization that landed in 2.7.0 only
+
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          mappings:
+            properties:
+              counter:
+                type: long
+
+  - do:
+      indices.create:
+        index: test_2
+        body:
+          mappings:
+            properties:
+              counter:
+                type: double
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+          - counter: 223372036854775800
+          - index:
+              _index: test_2
+          - counter: 1223372036854775800.23
+          - index:
+              _index: test_2
+          - counter: 184.4
+
+  - do:
+      search:
+        index: test_*
+        rest_total_hits_as_int: true
+        body:
+          sort: [{ counter: desc }]
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.0._source.counter: 1223372036854775800.23 }
+  - match: { hits.hits.0.sort.0: 1223372036854775800.23 }
+  - match: { hits.hits.1._index: test_1 }
+  - match: { hits.hits.1._source.counter: 223372036854775800 }
+  - match: { hits.hits.1.sort.0: 223372036854775800  }
+
+  - do:
+      search:
+        index: test_*
+        rest_total_hits_as_int: true
+        body:
+          sort: [{ counter: asc }]
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 3 }
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.0._source.counter: 184.4 }
+  - match: { hits.hits.0.sort.0: 184.4 }
+  - match: { hits.hits.1._index: test_1 }
+  - match: { hits.hits.1._source.counter: 223372036854775800 }
+  - match: { hits.hits.1.sort.0: 223372036854775800 }
+
+---
+"search across indices with mixed long, double and unsigned_long numeric types":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+        index: test_1
+        body:
+          mappings:
+            properties:
+              counter:
+                type: unsigned_long
+  - do:
+      indices.create:
+        index: test_2
+        body:
+          mappings:
+            properties:
+              counter:
+                type: long
+  - do:
+      indices.create:
+        index: test_3
+        body:
+          mappings:
+            properties:
+              counter:
+                type: double
+  - do:
+      bulk:
+        refresh: true
+        body:
+          - index:
+              _index: test_1
+          - counter: 10223372036854775800
+          - index:
+              _index: test_2
+          - counter: 223372036854775800
+          - index:
+              _index: test_3
+          - counter: 184.0
+
+  - do:
+      catch: bad_request
+      search:
+        index: test_*
+        rest_total_hits_as_int: true
+        body:
+          sort: [{ counter: asc }]
+  # The search across fields with mixed types (where one of those is unsigned_long) is not supported
+  - match: { status: 400 }
+  - match: { error.type: search_phase_execution_exception }
+  - match: { error.caused_by.reason: "Can't do sort across indices, as a field has [unsigned_long] type in one index, and different type in another index!" }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search/90_search_after.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search/90_search_after.yml
index 5f5d88dba7687..55e1566656faf 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search/90_search_after.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search/90_search_after.yml
@@ -160,6 +160,28 @@
   - match: {hits.hits.0._source.timestamp: "2019-10-21 00:30:04.828" }
   - match: {hits.hits.0.sort: [1571617804828] }
 
+  # search_after with the sort with missing
+  - do:
+      bulk:
+        refresh: true
+        index: test
+        body: |
+          {"index":{}}
+          {"timestamp": null}
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          "size": 5
+          "sort": [ { "timestamp": { "order": "asc", "missing": "_last" } } ]
+          search_after: [ "2021-10-21 08:30:04.828" ] # making it out of min/max so only missing value hit is qualified
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._index: test }
+  - match: { hits.hits.0._source.timestamp: null }
+
 ---
 "date_nanos":
   - skip:
@@ -225,3 +247,76 @@
   - match: {hits.hits.0._source.timestamp: "2019-10-21 00:30:04.828740" }
   - match: {hits.hits.0.sort: [1571617804828740000] }
 
+---
+"unsigned long":
+  - skip:
+      version: " - 2.7.99"
+      reason: unsigned_long is not supported before 2.8.0
+
+  - do:
+      indices.create:
+        index: test
+        body:
+          mappings:
+            properties:
+              population:
+                type: unsigned_long
+  - do:
+      bulk:
+        refresh: true
+        index: test
+        body: |
+          {"index":{}}
+          {"population": 10223372036854775800}
+          {"index":{}}
+          {"population": 15223372036854775800}
+
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          size: 1
+          sort: [{ population: asc }]
+  - match: {hits.total: 2 }
+  - length: {hits.hits: 1 }
+  - match: {hits.hits.0._index: test }
+  - match: {hits.hits.0._source.population: 10223372036854775800 }
+  - match: {hits.hits.0.sort: [10223372036854775800] }
+
+  # search_after with the sort
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          size: 1
+          sort: [{ population: asc }]
+          search_after: [10223372036854775800]
+  - match: {hits.total: 2 }
+  - length: {hits.hits: 1 }
+  - match: {hits.hits.0._index: test }
+  - match: {hits.hits.0._source.population: 15223372036854775800 }
+  - match: {hits.hits.0.sort: [15223372036854775800] }
+
+  # search_after with the sort with missing
+  - do:
+      bulk:
+        refresh: true
+        index: test
+        body: |
+          {"index":{}}
+          {"population": null}
+  - do:
+      search:
+        index: test
+        rest_total_hits_as_int: true
+        body:
+          "size": 5
+          "sort": [ { "population": { "order": "asc", "missing": "_last" } } ]
+          search_after: [15223372036854775801] # making it out of min/max so only missing value hit is qualified
+
+  - match: { hits.total: 3 }
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._index: test }
+  - match: { hits.hits.0._source.population: null }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search_pipeline/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search_pipeline/10_basic.yml
new file mode 100644
index 0000000000000..b7e6addff7ad4
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search_pipeline/10_basic.yml
@@ -0,0 +1,170 @@
+---
+# Only send sanity request to nodes in >=2.9 versions because search pipeline is GA in 2.9.0.
+# Nodes from earlier versions (before 2.9.0) will submit the request to nodes from 2.9.0
+# or later during the "mixedClusterTest," but this will fail because 2.9.0 removed the feature flag setting.
+
+"Test basic pipeline crud":
+  - skip:
+      version: " - 2.8.99"
+      reason: "Only send sanity request to nodes in >=2.9 versions"
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "request_processors": [
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.description: "_description" }
+
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+  - match: { acknowledged: true }
+
+  - do:
+      catch: missing
+      search_pipeline.get:
+        id: "my_pipeline"
+
+---
+"Test Put Versioned Pipeline":
+  - skip:
+      version: " - 2.8.99"
+      reason: "Only send sanity request to nodes in >=2.9 versions"
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "version": 10,
+            "request_processors": [ ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.version: 10 }
+
+  # Lower version
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "version": 9,
+            "request_processors": [ ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.version: 9 }
+
+  # Higher version
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "version": 6789,
+            "request_processors": [ ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.version: 6789 }
+
+  # No version
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "request_processors": [ ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - is_false: my_pipeline.version
+
+  # Coming back with a version
+  - do:
+      search_pipeline.put:
+        id: "my_pipeline"
+        body: >
+          {
+            "version": 5385,
+            "request_processors": [ ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      search_pipeline.get:
+        id: "my_pipeline"
+  - match: { my_pipeline.version: 5385 }
+
+  # Able to delete the versioned pipeline
+  - do:
+      search_pipeline.delete:
+        id: "my_pipeline"
+  - match: { acknowledged: true }
+
+  - do:
+      catch: missing
+      search_pipeline.get:
+        id: "my_pipeline"
+---
+"Test Get All Pipelines":
+  - skip:
+      version: " - 2.8.99"
+      reason: "Only send sanity request to nodes in >=2.9 versions"
+  - do:
+      search_pipeline.put:
+        id: "first_pipeline"
+        body:  >
+          {
+            "description": "first",
+            "request_processors": []
+          }
+  - do:
+      search_pipeline.put:
+        id: "second_pipeline"
+        body:  >
+          {
+            "description": "second",
+            "request_processors": []
+          }
+
+  - do:
+      search_pipeline.get: {}
+  - match: { first_pipeline.description: "first" }
+  - match: { second_pipeline.description: "second" }
+
+---
+"Test invalid config":
+  - skip:
+      version: " - 2.8.99"
+      reason: "Only send sanity request to nodes in >=2.9 versions"
+  - do:
+      catch: /parse_exception/
+      search_pipeline.put:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "request_processors": [],
+            "invalid_field" : {}
+          }
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/tasks.list/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/tasks.list/10_basic.yml
index d0385ac0125f4..aa0ebf46362d5 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/tasks.list/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/tasks.list/10_basic.yml
@@ -20,6 +20,35 @@
 
   - is_true: tasks
 
+---
+"tasks_list test detailed":
+  - skip:
+      features: [arbitrary_key]
+      version: " - 2.0.99"
+      reason: resource_stats were introduced in 2.1.0
+
+  - do:
+      nodes.info: {}
+  - set:
+      nodes._arbitrary_key_: node_id
+
+  - do:
+      tasks.list: {}
+
+  - is_true: nodes
+  - is_true: nodes.$node_id.roles
+
+  - do:
+      tasks.list:
+        group_by: parents
+        detailed: true
+  - set:
+      tasks._arbitrary_key_: task_id
+
+  - is_true: tasks
+  - is_true: tasks.$task_id.resource_stats
+  - is_true: tasks.$task_id.resource_stats.total
+
 ---
 "tasks_list headers":
   - skip:
@@ -33,3 +62,21 @@
   - is_true: tasks
   - match: { tasks.0.headers.X-Opaque-Id: "That is me" }
 
+---
+"tasks_list detailed (with thread info)":
+  - skip:
+      version: " - 2.8.99"
+      reason: thread_info was introduced in 2.9.0
+      features: [arbitrary_key]
+
+  - do:
+      tasks.list:
+        group_by: parents
+        detailed: true
+  - set:
+      tasks._arbitrary_key_: task_id
+
+  - is_true: tasks
+  - is_true: tasks.$task_id.resource_stats
+  - is_true: tasks.$task_id.resource_stats.thread_info
+  - is_true: tasks.$task_id.resource_stats.total
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/update/20_doc_upsert.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/update/20_doc_upsert.yml
index 4d03971aba252..cfdd38b9ffd1c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/update/20_doc_upsert.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/update/20_doc_upsert.yml
@@ -32,5 +32,3 @@
 
   - match:  { _source.foo:        bar }
   - match:  { _source.count:      1   }
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/update/22_doc_as_upsert.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/update/22_doc_as_upsert.yml
index c65fc5af27fcc..7ee5c01089ff1 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/update/22_doc_as_upsert.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/update/22_doc_as_upsert.yml
@@ -32,5 +32,3 @@
 
   - match:  { _source.foo:   bar }
   - match:  { _source.count: 2   }
-
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/update/35_if_seq_no.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/update/35_if_seq_no.yml
index f982adf693ad0..c93be37be49f5 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/update/35_if_seq_no.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/update/35_if_seq_no.yml
@@ -61,4 +61,3 @@
 
  - match: { errors: true }
  - match: { items.0.update.status: 409 }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/update/40_routing.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/update/40_routing.yml
index 6f43d381e0537..28e42f9dafea9 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/update/40_routing.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/update/40_routing.yml
@@ -55,4 +55,3 @@
             doc:        { foo: baz }
 
  - match: { get._source.foo: baz }
-
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/update/85_fields_meta.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/update/85_fields_meta.yml
index fe76ab5299cda..2d4fda22f4442 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/update/85_fields_meta.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/update/85_fields_meta.yml
@@ -27,5 +27,3 @@
           id:     1
           parent: 5
           stored_fields: [ _routing ]
-
-
diff --git a/rest-api-spec/src/yamlRestTest/java/org/opensearch/test/rest/ClientYamlTestSuiteIT.java b/rest-api-spec/src/yamlRestTest/java/org/opensearch/test/rest/ClientYamlTestSuiteIT.java
index 9a1973e9d5aeb..a7f196190c350 100644
--- a/rest-api-spec/src/yamlRestTest/java/org/opensearch/test/rest/ClientYamlTestSuiteIT.java
+++ b/rest-api-spec/src/yamlRestTest/java/org/opensearch/test/rest/ClientYamlTestSuiteIT.java
@@ -33,8 +33,8 @@
 package org.opensearch.test.rest;
 
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
-
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
+
 import org.apache.lucene.tests.util.TimeUnits;
 import org.opensearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
diff --git a/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java b/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java
new file mode 100644
index 0000000000000..0b88abb314fcd
--- /dev/null
+++ b/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java
@@ -0,0 +1,316 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.profile.query;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field.Store;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.Explanation;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.LRUQueryCache;
+import org.apache.lucene.search.LeafCollector;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.QueryCachingPolicy;
+import org.apache.lucene.search.QueryVisitor;
+import org.apache.lucene.search.ScoreMode;
+import org.apache.lucene.search.Scorer;
+import org.apache.lucene.search.ScorerSupplier;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.search.TotalHitCountCollector;
+import org.apache.lucene.search.Weight;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.RandomApproximationQuery;
+import org.apache.lucene.tests.util.TestUtil;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.profile.ProfileResult;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+
+public class QueryProfilerTests extends OpenSearchTestCase {
+
+    private Directory dir;
+    private IndexReader reader;
+    private ContextIndexSearcher searcher;
+    private ExecutorService executor;
+
+    @ParametersFactory
+    public static Collection<Object[]> concurrency() {
+        return Arrays.asList(new Integer[] { 0 }, new Integer[] { 5 });
+    }
+
+    public QueryProfilerTests(int concurrency) {
+        this.executor = (concurrency > 0) ? Executors.newFixedThreadPool(concurrency) : null;
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+
+        dir = newDirectory();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir);
+        final int numDocs = TestUtil.nextInt(random(), 1, 20);
+        for (int i = 0; i < numDocs; ++i) {
+            final int numHoles = random().nextInt(5);
+            for (int j = 0; j < numHoles; ++j) {
+                w.addDocument(new Document());
+            }
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            w.addDocument(doc);
+        }
+        reader = w.getReader();
+        w.close();
+        searcher = new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            ALWAYS_CACHE_POLICY,
+            true,
+            executor
+        );
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+
+        LRUQueryCache cache = (LRUQueryCache) searcher.getQueryCache();
+        assertThat(cache.getHitCount(), equalTo(0L));
+        assertThat(cache.getCacheCount(), equalTo(0L));
+        assertThat(cache.getTotalCount(), equalTo(cache.getMissCount()));
+        assertThat(cache.getCacheSize(), equalTo(0L));
+
+        if (executor != null) {
+            ThreadPool.terminate(executor, 10, TimeUnit.SECONDS);
+        }
+
+        IOUtils.close(reader, dir);
+        dir = null;
+        reader = null;
+        searcher = null;
+    }
+
+    public void testBasic() throws IOException {
+        QueryProfiler profiler = new QueryProfiler(executor != null);
+        searcher.setProfiler(profiler);
+        Query query = new TermQuery(new Term("foo", "bar"));
+        searcher.search(query, 1);
+        List<ProfileResult> results = profiler.getTree();
+        assertEquals(1, results.size());
+        Map<String, Long> breakdown = results.get(0).getTimeBreakdown();
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString()), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString()), equalTo(0L));
+
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString() + "_count"), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString() + "_count"), equalTo(0L));
+
+        long rewriteTime = profiler.getRewriteTime();
+        assertThat(rewriteTime, greaterThan(0L));
+    }
+
+    public void testNoScoring() throws IOException {
+        QueryProfiler profiler = new QueryProfiler(executor != null);
+        searcher.setProfiler(profiler);
+        Query query = new TermQuery(new Term("foo", "bar"));
+        searcher.search(query, 1, Sort.INDEXORDER); // scores are not needed
+        List<ProfileResult> results = profiler.getTree();
+        assertEquals(1, results.size());
+        Map<String, Long> breakdown = results.get(0).getTimeBreakdown();
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString()), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString()), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString()), equalTo(0L));
+
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString() + "_count"), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString() + "_count"), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString() + "_count"), equalTo(0L));
+
+        long rewriteTime = profiler.getRewriteTime();
+        assertThat(rewriteTime, greaterThan(0L));
+    }
+
+    public void testUseIndexStats() throws IOException {
+        QueryProfiler profiler = new QueryProfiler(executor != null);
+        searcher.setProfiler(profiler);
+        Query query = new TermQuery(new Term("foo", "bar"));
+        searcher.count(query); // will use index stats
+        List<ProfileResult> results = profiler.getTree();
+        assertEquals(1, results.size());
+        ProfileResult result = results.get(0);
+        assertEquals(0, (long) result.getTimeBreakdown().get("build_scorer_count"));
+
+        long rewriteTime = profiler.getRewriteTime();
+        assertThat(rewriteTime, greaterThan(0L));
+    }
+
+    public void testApproximations() throws IOException {
+        QueryProfiler profiler = new QueryProfiler(executor != null);
+        searcher.setProfiler(profiler);
+        Query query = new RandomApproximationQuery(new TermQuery(new Term("foo", "bar")), random());
+        searcher.count(query);
+        List<ProfileResult> results = profiler.getTree();
+        assertEquals(1, results.size());
+        Map<String, Long> breakdown = results.get(0).getTimeBreakdown();
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString()), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString()), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString()), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString()), greaterThan(0L));
+
+        assertThat(breakdown.get(QueryTimingType.CREATE_WEIGHT.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.BUILD_SCORER.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.NEXT_DOC.toString() + "_count"), greaterThan(0L));
+        assertThat(breakdown.get(QueryTimingType.ADVANCE.toString() + "_count"), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.SCORE.toString() + "_count"), equalTo(0L));
+        assertThat(breakdown.get(QueryTimingType.MATCH.toString() + "_count"), greaterThan(0L));
+
+        long rewriteTime = profiler.getRewriteTime();
+        assertThat(rewriteTime, greaterThan(0L));
+    }
+
+    public void testCollector() throws IOException {
+        TotalHitCountCollector collector = new TotalHitCountCollector();
+        ProfileCollector profileCollector = new ProfileCollector(collector);
+        assertEquals(0, profileCollector.getTime());
+        final LeafCollector leafCollector = profileCollector.getLeafCollector(reader.leaves().get(0));
+        assertThat(profileCollector.getTime(), greaterThan(0L));
+        long time = profileCollector.getTime();
+        leafCollector.setScorer(null);
+        assertThat(profileCollector.getTime(), greaterThan(time));
+        time = profileCollector.getTime();
+        leafCollector.collect(0);
+        assertThat(profileCollector.getTime(), greaterThan(time));
+    }
+
+    private static class DummyQuery extends Query {
+
+        @Override
+        public String toString(String field) {
+            return getClass().getSimpleName();
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            return this == obj;
+        }
+
+        @Override
+        public int hashCode() {
+            return 0;
+        }
+
+        @Override
+        public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException {
+            return new Weight(this) {
+                @Override
+                public Explanation explain(LeafReaderContext context, int doc) throws IOException {
+                    throw new UnsupportedOperationException();
+                }
+
+                @Override
+                public Scorer scorer(LeafReaderContext context) throws IOException {
+                    throw new UnsupportedOperationException();
+                }
+
+                @Override
+                public ScorerSupplier scorerSupplier(LeafReaderContext context) throws IOException {
+                    return new ScorerSupplier() {
+
+                        @Override
+                        public Scorer get(long loadCost) throws IOException {
+                            throw new UnsupportedOperationException();
+                        }
+
+                        @Override
+                        public long cost() {
+                            return 42;
+                        }
+                    };
+                }
+
+                @Override
+                public boolean isCacheable(LeafReaderContext ctx) {
+                    return true;
+                }
+            };
+        }
+
+        @Override
+        public void visit(QueryVisitor visitor) {
+            visitor.visitLeaf(this);
+        }
+    }
+
+    public void testScorerSupplier() throws IOException {
+        Directory dir = newDirectory();
+        IndexWriter w = new IndexWriter(dir, newIndexWriterConfig());
+        w.addDocument(new Document());
+        DirectoryReader reader = DirectoryReader.open(w);
+        w.close();
+        IndexSearcher s = newSearcher(reader);
+        s.setQueryCache(null);
+        Weight weight = s.createWeight(s.rewrite(new DummyQuery()), randomFrom(ScoreMode.values()), 1f);
+        // exception when getting the scorer
+        expectThrows(UnsupportedOperationException.class, () -> weight.scorer(s.getIndexReader().leaves().get(0)));
+        // no exception, means scorerSupplier is delegated
+        weight.scorerSupplier(s.getIndexReader().leaves().get(0));
+        reader.close();
+        dir.close();
+    }
+
+    private static final QueryCachingPolicy ALWAYS_CACHE_POLICY = new QueryCachingPolicy() {
+
+        @Override
+        public void onUse(Query query) {}
+
+        @Override
+        public boolean shouldCache(Query query) throws IOException {
+            return true;
+        }
+
+    };
+}
diff --git a/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/query/QueryPhaseTests.java b/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/query/QueryPhaseTests.java
new file mode 100644
index 0000000000000..a39a0cee9dbab
--- /dev/null
+++ b/sandbox/plugins/concurrent-search/src/test/java/org/opensearch/search/query/QueryPhaseTests.java
@@ -0,0 +1,1333 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.query;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field.Store;
+import org.apache.lucene.document.LatLonDocValuesField;
+import org.apache.lucene.document.LatLonPoint;
+import org.apache.lucene.document.LongPoint;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.SortedSetDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.queries.spans.SpanNearQuery;
+import org.apache.lucene.queries.spans.SpanTermQuery;
+import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.BooleanClause.Occur;
+import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.ConstantScoreQuery;
+import org.apache.lucene.search.DocValuesFieldExistsQuery;
+import org.apache.lucene.search.FieldComparator;
+import org.apache.lucene.search.FieldDoc;
+import org.apache.lucene.search.FilterCollector;
+import org.apache.lucene.search.FilterLeafCollector;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.LeafCollector;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.MatchNoDocsQuery;
+import org.apache.lucene.search.MultiTermQuery;
+import org.apache.lucene.search.PrefixQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TopFieldDocs;
+import org.apache.lucene.search.TotalHitCountCollector;
+import org.apache.lucene.search.TotalHits;
+import org.apache.lucene.search.Weight;
+import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
+import org.apache.lucene.search.join.BitSetProducer;
+import org.apache.lucene.search.join.ScoreMode;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.FixedBitSet;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.mapper.DateFieldMapper;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberType;
+import org.opensearch.index.query.ParsedQuery;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.search.OpenSearchToParentBlockJoinQuery;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.lucene.queries.MinDocQuery;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.collapse.CollapseBuilder;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.ScrollContext;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.sort.SortAndFormats;
+import org.opensearch.tasks.TaskCancelledException;
+import org.opensearch.test.TestSearchContext;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.anyOf;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+import static org.opensearch.search.query.TopDocsCollectorContext.hasInfMaxScore;
+
+public class QueryPhaseTests extends IndexShardTestCase {
+
+    private IndexShard indexShard;
+    private final ExecutorService executor;
+    private final QueryPhaseSearcher queryPhaseSearcher;
+
+    @ParametersFactory
+    public static Collection<Object[]> concurrency() {
+        return Arrays.asList(
+            new Object[] { 0, QueryPhase.DEFAULT_QUERY_PHASE_SEARCHER },
+            new Object[] { 5, new ConcurrentQueryPhaseSearcher() }
+        );
+    }
+
+    public QueryPhaseTests(int concurrency, QueryPhaseSearcher queryPhaseSearcher) {
+        this.executor = (concurrency > 0) ? Executors.newFixedThreadPool(concurrency) : null;
+        this.queryPhaseSearcher = queryPhaseSearcher;
+    }
+
+    @Override
+    public Settings threadPoolSettings() {
+        return Settings.builder().put(super.threadPoolSettings()).put("thread_pool.search.min_queue_size", 10).build();
+    }
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        indexShard = newShard(true);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        closeShards(indexShard);
+
+        if (executor != null) {
+            ThreadPool.terminate(executor, 10, TimeUnit.SECONDS);
+        }
+    }
+
+    private void countTestCase(Query query, IndexReader reader, boolean shouldCollectSearch, boolean shouldCollectCount) throws Exception {
+        ContextIndexSearcher searcher = shouldCollectSearch
+            ? newContextSearcher(reader, executor)
+            : newEarlyTerminationContextSearcher(reader, 0, executor);
+        TestSearchContext context = new TestSearchContext(null, indexShard, searcher);
+        context.parsedQuery(new ParsedQuery(query));
+        context.setSize(0);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        final boolean rescore = QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(rescore);
+
+        ContextIndexSearcher countSearcher = shouldCollectCount
+            ? newContextSearcher(reader, executor)
+            : newEarlyTerminationContextSearcher(reader, 0, executor);
+        assertEquals(countSearcher.count(query), context.queryResult().topDocs().topDocs.totalHits.value);
+    }
+
+    private void countTestCase(boolean withDeletions) throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig().setMergePolicy(NoMergePolicy.INSTANCE);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "bar", Store.NO));
+                doc.add(new SortedSetDocValuesField("foo", new BytesRef("bar")));
+                doc.add(new SortedSetDocValuesField("docValuesOnlyField", new BytesRef("bar")));
+                doc.add(new LatLonDocValuesField("latLonDVField", 1.0, 1.0));
+                doc.add(new LatLonPoint("latLonDVField", 1.0, 1.0));
+            }
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "baz", Store.NO));
+                doc.add(new SortedSetDocValuesField("foo", new BytesRef("baz")));
+            }
+            if (withDeletions && (rarely() || i == 0)) {
+                doc.add(new StringField("delete", "yes", Store.NO));
+            }
+            w.addDocument(doc);
+        }
+        if (withDeletions) {
+            w.deleteDocuments(new Term("delete", "yes"));
+        }
+        final IndexReader reader = w.getReader();
+        Query matchAll = new MatchAllDocsQuery();
+        Query matchAllCsq = new ConstantScoreQuery(matchAll);
+        Query tq = new TermQuery(new Term("foo", "bar"));
+        Query tCsq = new ConstantScoreQuery(tq);
+        Query dvfeq = new DocValuesFieldExistsQuery("foo");
+        Query dvfeq_points = new DocValuesFieldExistsQuery("latLonDVField");
+        Query dvfeqCsq = new ConstantScoreQuery(dvfeq);
+        // field with doc-values but not indexed will need to collect
+        Query dvOnlyfeq = new DocValuesFieldExistsQuery("docValuesOnlyField");
+        BooleanQuery bq = new BooleanQuery.Builder().add(matchAll, Occur.SHOULD).add(tq, Occur.MUST).build();
+
+        countTestCase(matchAll, reader, false, false);
+        countTestCase(matchAllCsq, reader, false, false);
+        countTestCase(tq, reader, withDeletions, withDeletions);
+        countTestCase(tCsq, reader, withDeletions, withDeletions);
+        countTestCase(dvfeq, reader, withDeletions, true);
+        countTestCase(dvfeq_points, reader, withDeletions, true);
+        countTestCase(dvfeqCsq, reader, withDeletions, true);
+        countTestCase(dvOnlyfeq, reader, true, true);
+        countTestCase(bq, reader, true, true);
+        reader.close();
+        w.close();
+        dir.close();
+    }
+
+    public void testCountWithoutDeletions() throws Exception {
+        countTestCase(false);
+    }
+
+    public void testCountWithDeletions() throws Exception {
+        countTestCase(true);
+    }
+
+    public void testPostFilterDisablesCountOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+
+        context.setSearcher(newContextSearcher(reader, executor));
+        context.parsedPostFilter(new ParsedQuery(new MatchNoDocsQuery()));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
+        reader.close();
+        dir.close();
+    }
+
+    public void testTerminateAfterWithFilter() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        for (int i = 0; i < 10; i++) {
+            doc.add(new StringField("foo", Integer.toString(i), Store.NO));
+        }
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.terminateAfter(1);
+        context.setSize(10);
+        for (int i = 0; i < 10; i++) {
+            context.parsedPostFilter(new ParsedQuery(new TermQuery(new Term("foo", Integer.toString(i)))));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testMinScoreDisablesCountOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.setSize(0);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+
+        context.minimumScore(100);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertEquals(TotalHits.Relation.EQUAL_TO, context.queryResult().topDocs().topDocs.totalHits.relation);
+        reader.close();
+        dir.close();
+    }
+
+    public void testQueryCapturesThreadPoolStats() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            w.addDocument(new Document());
+        }
+        w.close();
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        QuerySearchResult results = context.queryResult();
+        assertThat(results.serviceTimeEWMA(), greaterThanOrEqualTo(0L));
+        assertThat(results.nodeQueueSize(), greaterThanOrEqualTo(0));
+        reader.close();
+        dir.close();
+    }
+
+    public void testInOrderScrollOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            w.addDocument(new Document());
+        }
+        w.close();
+        IndexReader reader = DirectoryReader.open(dir);
+        ScrollContext scrollContext = new ScrollContext();
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        scrollContext.lastEmittedDoc = null;
+        scrollContext.maxScore = Float.NaN;
+        scrollContext.totalHits = null;
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        int size = randomIntBetween(2, 5);
+        context.setSize(size);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertNull(context.queryResult().terminatedEarly());
+        assertThat(context.terminateAfter(), equalTo(0));
+        assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+
+        context.setSearcher(newEarlyTerminationContextSearcher(reader, size, executor));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0].doc, greaterThanOrEqualTo(size));
+        reader.close();
+        dir.close();
+    }
+
+    public void testTerminateAfterEarlyTermination() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "bar", Store.NO));
+            }
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "baz", Store.NO));
+            }
+            doc.add(new NumericDocValuesField("rank", numDocs - i));
+            w.addDocument(doc);
+        }
+        w.close();
+        final IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+
+        context.terminateAfter(numDocs);
+        {
+            context.setSize(10);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertFalse(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(10));
+            assertThat(manager.getTotalHits(), equalTo(numDocs));
+        }
+
+        context.terminateAfter(1);
+        {
+            context.setSize(1);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+
+            context.setSize(0);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+        }
+
+        {
+            context.setSize(1);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+        }
+        {
+            context.setSize(1);
+            BooleanQuery bq = new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.SHOULD)
+                .add(new TermQuery(new Term("foo", "baz")), Occur.SHOULD)
+                .build();
+            context.parsedQuery(new ParsedQuery(bq));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+
+            context.setSize(0);
+            context.parsedQuery(new ParsedQuery(bq));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+        }
+        {
+            context.setSize(1);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, 1);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(manager.getTotalHits(), equalTo(1));
+            context.queryCollectorManagers().clear();
+        }
+        {
+            context.setSize(0);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, 1);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+            assertThat(manager.getTotalHits(), equalTo(1));
+        }
+
+        // tests with trackTotalHits and terminateAfter
+        context.terminateAfter(10);
+        context.setSize(0);
+        for (int trackTotalHits : new int[] { -1, 3, 76, 100 }) {
+            context.trackTotalHitsUpTo(trackTotalHits);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            if (trackTotalHits == -1) {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(0L));
+            } else {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) Math.min(trackTotalHits, 10)));
+            }
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+            // The concurrent search terminates the collection when the number of hits is reached by each
+            // concurrent collector. In this case, in general, the number of results are multiplied by the number of
+            // slices (as the unit of concurrency). To address that, we have to use the shared global state,
+            // much as HitsThresholdChecker does.
+            if (executor == null) {
+                assertThat(manager.getTotalHits(), equalTo(10));
+            }
+        }
+
+        context.terminateAfter(7);
+        context.setSize(10);
+        for (int trackTotalHits : new int[] { -1, 3, 75, 100 }) {
+            context.trackTotalHitsUpTo(trackTotalHits);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            if (trackTotalHits == -1) {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(0L));
+            } else {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(7L));
+            }
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(7));
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testIndexSortingEarlyTermination() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "bar", Store.NO));
+            }
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "baz", Store.NO));
+            }
+            doc.add(new NumericDocValuesField("rank", numDocs - i));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        final IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.setSize(1);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+        FieldDoc fieldDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[0];
+        assertThat(fieldDoc.fields[0], equalTo(1));
+
+        {
+            context.parsedPostFilter(new ParsedQuery(new MinDocQuery(1)));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(numDocs - 1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+            context.parsedPostFilter(null);
+
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, sort);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+            // When searching concurrently, each executors short-circuits when "size" is reached,
+            // including total hits collector
+            assertThat(manager.getTotalHits(), lessThanOrEqualTo(numDocs));
+
+            context.queryCollectorManagers().clear();
+        }
+
+        {
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 1, executor));
+            context.trackTotalHitsUpTo(SearchContext.TRACK_TOTAL_HITS_DISABLED);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testIndexSortScrollOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort indexSort = new Sort(new SortField("rank", SortField.Type.INT), new SortField("tiebreaker", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(indexSort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            doc.add(new NumericDocValuesField("rank", random().nextInt()));
+            doc.add(new NumericDocValuesField("tiebreaker", i));
+            w.addDocument(doc);
+        }
+        if (randomBoolean()) {
+            w.forceMerge(randomIntBetween(1, 10));
+        }
+        w.close();
+
+        final IndexReader reader = DirectoryReader.open(dir);
+        List<SortAndFormats> searchSortAndFormats = new ArrayList<>();
+        searchSortAndFormats.add(new SortAndFormats(indexSort, new DocValueFormat[] { DocValueFormat.RAW, DocValueFormat.RAW }));
+        // search sort is a prefix of the index sort
+        searchSortAndFormats.add(new SortAndFormats(new Sort(indexSort.getSort()[0]), new DocValueFormat[] { DocValueFormat.RAW }));
+        for (SortAndFormats searchSortAndFormat : searchSortAndFormats) {
+            ScrollContext scrollContext = new ScrollContext();
+            TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
+            context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+            scrollContext.lastEmittedDoc = null;
+            scrollContext.maxScore = Float.NaN;
+            scrollContext.totalHits = null;
+            context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+            context.setSize(10);
+            context.sort(searchSortAndFormat);
+
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.terminateAfter(), equalTo(0));
+            assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+            int sizeMinus1 = context.queryResult().topDocs().topDocs.scoreDocs.length - 1;
+            FieldDoc lastDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[sizeMinus1];
+
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 10, executor));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertThat(context.terminateAfter(), equalTo(0));
+            assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+            FieldDoc firstDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[0];
+            for (int i = 0; i < searchSortAndFormat.sort.getSort().length; i++) {
+                @SuppressWarnings("unchecked")
+                FieldComparator<Object> comparator = (FieldComparator<Object>) searchSortAndFormat.sort.getSort()[i].getComparator(
+                    i,
+                    false
+                );
+                int cmp = comparator.compareValues(firstDoc.fields[i], lastDoc.fields[i]);
+                if (cmp == 0) {
+                    continue;
+                }
+                assertThat(cmp, equalTo(1));
+                break;
+            }
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testDisableTopScoreCollection() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig(new StandardAnalyzer());
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        final int numDocs = 2 * scaledRandomIntBetween(50, 450);
+        for (int i = 0; i < numDocs; i++) {
+            doc.clear();
+            if (i % 2 == 0) {
+                doc.add(new TextField("title", "foo bar", Store.NO));
+            } else {
+                doc.add(new TextField("title", "foo", Store.NO));
+            }
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        Query q = new SpanNearQuery.Builder("title", true).addClause(new SpanTermQuery(new Term("title", "foo")))
+            .addClause(new SpanTermQuery(new Term("title", "bar")))
+            .build();
+
+        context.parsedQuery(new ParsedQuery(q));
+        context.setSize(3);
+        context.trackTotalHitsUpTo(3);
+        TopDocsCollectorContext topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
+        assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.COMPLETE);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.EQUAL_TO);
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
+
+        context.sort(new SortAndFormats(new Sort(new SortField("other", SortField.Type.INT)), new DocValueFormat[] { DocValueFormat.RAW }));
+        topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
+        assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.TOP_DOCS);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
+        assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testEnhanceSortOnNumeric() throws Exception {
+        final String fieldNameLong = "long-field";
+        final String fieldNameDate = "date-field";
+        MappedFieldType fieldTypeLong = new NumberFieldMapper.NumberFieldType(fieldNameLong, NumberFieldMapper.NumberType.LONG);
+        MappedFieldType fieldTypeDate = new DateFieldMapper.DateFieldType(fieldNameDate);
+        MapperService mapperService = mock(MapperService.class);
+        when(mapperService.fieldType(fieldNameLong)).thenReturn(fieldTypeLong);
+        when(mapperService.fieldType(fieldNameDate)).thenReturn(fieldTypeDate);
+        // enough docs to have a tree with several leaf nodes
+        final int numDocs = 3500 * 5;
+        Directory dir = newDirectory();
+        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(null));
+        long firstValue = randomLongBetween(-10000000L, 10000000L);
+        long longValue = firstValue;
+        long dateValue = randomLongBetween(0, 3000000000000L);
+        for (int i = 1; i <= numDocs; ++i) {
+            Document doc = new Document();
+
+            doc.add(new LongPoint(fieldNameLong, longValue));
+            doc.add(new NumericDocValuesField(fieldNameLong, longValue));
+
+            doc.add(new LongPoint(fieldNameDate, dateValue));
+            doc.add(new NumericDocValuesField(fieldNameDate, dateValue));
+            writer.addDocument(doc);
+            longValue++;
+            dateValue++;
+            if (i % 3500 == 0) writer.commit();
+        }
+        writer.close();
+        final IndexReader reader = DirectoryReader.open(dir);
+        final SortField sortFieldLong = new SortField(fieldNameLong, SortField.Type.LONG);
+        sortFieldLong.setMissingValue(Long.MAX_VALUE);
+        final SortField sortFieldDate = new SortField(fieldNameDate, SortField.Type.LONG);
+        sortFieldDate.setMissingValue(Long.MAX_VALUE);
+        DocValueFormat dateFormat = fieldTypeDate.docValueFormat(null, null);
+        final Sort longSort = new Sort(sortFieldLong);
+        final Sort longDateSort = new Sort(sortFieldLong, sortFieldDate);
+        final Sort dateSort = new Sort(sortFieldDate);
+        final Sort dateLongSort = new Sort(sortFieldDate, sortFieldLong);
+        SortAndFormats longSortAndFormats = new SortAndFormats(longSort, new DocValueFormat[] { DocValueFormat.RAW });
+        SortAndFormats longDateSortAndFormats = new SortAndFormats(longDateSort, new DocValueFormat[] { DocValueFormat.RAW, dateFormat });
+        SortAndFormats dateSortAndFormats = new SortAndFormats(dateSort, new DocValueFormat[] { dateFormat });
+        SortAndFormats dateLongSortAndFormats = new SortAndFormats(dateLongSort, new DocValueFormat[] { dateFormat, DocValueFormat.RAW });
+        ParsedQuery query = new ParsedQuery(new MatchAllDocsQuery());
+        SearchShardTask task = new SearchShardTask(123L, "", "", "", null, Collections.emptyMap());
+
+        // 1. Test a sort on long field
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(longSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(10);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
+        }
+
+        // 2. Test a sort on long field + date field
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(longDateSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(10);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, true);
+        }
+
+        // 3. Test a sort on date field
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(dateSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(10);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
+        }
+
+        // 4. Test a sort on date field + long field
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(dateLongSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(10);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, true);
+        }
+
+        // 5. Test that sort optimization is run when from > 0 and size = 0
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(longSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.from(5);
+            searchContext.setSize(0);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
+        }
+
+        // 6. Test that sort optimization works with from = 0 and size= 0
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            searchContext.sort(longSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(0);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+        }
+
+        // 7. Test that sort optimization works with search after
+        {
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
+            when(searchContext.mapperService()).thenReturn(mapperService);
+            int afterDocument = (int) randomLongBetween(0, 50);
+            long afterValue = firstValue + afterDocument;
+            FieldDoc after = new FieldDoc(afterDocument, Float.NaN, new Long[] { afterValue });
+            searchContext.searchAfter(after);
+            searchContext.sort(longSortAndFormats);
+            searchContext.parsedQuery(query);
+            searchContext.setTask(task);
+            searchContext.setSize(10);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
+            final TopDocs topDocs = searchContext.queryResult().topDocs().topDocs;
+            long topValue = (long) ((FieldDoc) topDocs.scoreDocs[0]).fields[0];
+            assertThat(topValue, greaterThan(afterValue));
+            assertSortResults(topDocs, (long) numDocs, false);
+
+            final TotalHits totalHits = topDocs.totalHits;
+            assertEquals(TotalHits.Relation.EQUAL_TO, totalHits.relation);
+            assertEquals(numDocs, totalHits.value);
+        }
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testMaxScoreQueryVisitor() {
+        BitSetProducer producer = context -> new FixedBitSet(1);
+        Query query = new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.Avg, "nested");
+        assertTrue(hasInfMaxScore(query));
+
+        query = new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.None, "nested");
+        assertFalse(hasInfMaxScore(query));
+
+        for (Occur occur : Occur.values()) {
+            query = new BooleanQuery.Builder().add(
+                new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.Avg, "nested"),
+                occur
+            ).build();
+            if (occur == Occur.MUST) {
+                assertTrue(hasInfMaxScore(query));
+            } else {
+                assertFalse(hasInfMaxScore(query));
+            }
+
+            query = new BooleanQuery.Builder().add(
+                new BooleanQuery.Builder().add(
+                    new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.Avg, "nested"),
+                    occur
+                ).build(),
+                occur
+            ).build();
+            if (occur == Occur.MUST) {
+                assertTrue(hasInfMaxScore(query));
+            } else {
+                assertFalse(hasInfMaxScore(query));
+            }
+
+            query = new BooleanQuery.Builder().add(
+                new BooleanQuery.Builder().add(
+                    new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.Avg, "nested"),
+                    occur
+                ).build(),
+                Occur.FILTER
+            ).build();
+            assertFalse(hasInfMaxScore(query));
+
+            query = new BooleanQuery.Builder().add(
+                new BooleanQuery.Builder().add(new SpanTermQuery(new Term("field", "foo")), occur)
+                    .add(new OpenSearchToParentBlockJoinQuery(new MatchAllDocsQuery(), producer, ScoreMode.Avg, "nested"), occur)
+                    .build(),
+                occur
+            ).build();
+            if (occur == Occur.MUST) {
+                assertTrue(hasInfMaxScore(query));
+            } else {
+                assertFalse(hasInfMaxScore(query));
+            }
+        }
+    }
+
+    // assert score docs are in order and their number is as expected
+    private void assertSortResults(TopDocs topDocs, long expectedNumDocs, boolean isDoubleSort) {
+        if (topDocs.totalHits.relation == TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO) {
+            assertThat(topDocs.totalHits.value, lessThanOrEqualTo(expectedNumDocs));
+        } else {
+            assertEquals(topDocs.totalHits.value, expectedNumDocs);
+        }
+        long cur1, cur2;
+        long prev1 = Long.MIN_VALUE;
+        long prev2 = Long.MIN_VALUE;
+        for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
+            cur1 = (long) ((FieldDoc) scoreDoc).fields[0];
+            assertThat(cur1, greaterThanOrEqualTo(prev1)); // test that docs are properly sorted on the first sort
+            if (isDoubleSort) {
+                cur2 = (long) ((FieldDoc) scoreDoc).fields[1];
+                if (cur1 == prev1) {
+                    assertThat(cur2, greaterThanOrEqualTo(prev2)); // test that docs are properly sorted on the secondary sort
+                }
+                prev2 = cur2;
+            }
+            prev1 = cur1;
+        }
+    }
+
+    public void testMinScore() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        for (int i = 0; i < 10; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new StringField("filter", "f1", Store.NO));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.parsedQuery(
+            new ParsedQuery(
+                new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+                    .add(new TermQuery(new Term("filter", "f1")), Occur.SHOULD)
+                    .build()
+            )
+        );
+        context.minimumScore(0.01f);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(1);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(10, context.queryResult().topDocs().topDocs.totalHits.value);
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testMaxScore() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("filter", SortField.Type.STRING));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new StringField("filter", "f1" + ((i > 0) ? " " + Integer.toString(i) : ""), Store.NO));
+            doc.add(new SortedDocValuesField("filter", newBytesRef("f1" + ((i > 0) ? " " + Integer.toString(i) : ""))));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.trackScores(true);
+        context.parsedQuery(
+            new ParsedQuery(
+                new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+                    .add(new TermQuery(new Term("filter", "f1")), Occur.SHOULD)
+                    .build()
+            )
+        );
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(1);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        context.trackScores(false);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertTrue(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testCollapseQuerySearchResults() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("user", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        // Always end up with uneven buckets so collapsing is predictable
+        final int numDocs = 2 * scaledRandomIntBetween(600, 900) - 1;
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new NumericDocValuesField("user", i & 1));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        when(queryShardContext.fieldMapper("user")).thenReturn(
+            new NumberFieldType("user", NumberType.INTEGER, true, false, true, false, null, Collections.emptyMap())
+        );
+
+        TestSearchContext context = new TestSearchContext(queryShardContext, indexShard, newContextSearcher(reader, executor));
+        context.collapse(new CollapseBuilder("user").build(context.getQueryShardContext()));
+        context.trackScores(true);
+        context.parsedQuery(new ParsedQuery(new TermQuery(new Term("foo", "bar"))));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(2);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        CollapseTopFieldDocs topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        context.trackScores(false);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertTrue(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testCancellationDuringPreprocess() throws IOException {
+        try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir, newIndexWriterConfig())) {
+
+            for (int i = 0; i < 10; i++) {
+                Document doc = new Document();
+                StringBuilder sb = new StringBuilder();
+                for (int j = 0; j < i; j++) {
+                    sb.append('a');
+                }
+                doc.add(new StringField("foo", sb.toString(), Store.NO));
+                w.addDocument(doc);
+            }
+            w.flush();
+            w.close();
+
+            try (IndexReader reader = DirectoryReader.open(dir)) {
+                TestSearchContext context = new TestSearchContextWithRewriteAndCancellation(
+                    null,
+                    indexShard,
+                    newContextSearcher(reader, executor)
+                );
+                PrefixQuery prefixQuery = new PrefixQuery(new Term("foo", "a"), MultiTermQuery.SCORING_BOOLEAN_REWRITE);
+                context.parsedQuery(new ParsedQuery(prefixQuery));
+                SearchShardTask task = mock(SearchShardTask.class);
+                when(task.isCancelled()).thenReturn(true);
+                context.setTask(task);
+                expectThrows(TaskCancelledException.class, () -> new QueryPhase().preProcess(context));
+            }
+        }
+    }
+
+    private static class TestSearchContextWithRewriteAndCancellation extends TestSearchContext {
+
+        private TestSearchContextWithRewriteAndCancellation(
+            QueryShardContext queryShardContext,
+            IndexShard indexShard,
+            ContextIndexSearcher searcher
+        ) {
+            super(queryShardContext, indexShard, searcher);
+        }
+
+        @Override
+        public void preProcess(boolean rewrite) {
+            try {
+                searcher().rewrite(query());
+            } catch (IOException e) {
+                fail("IOException shouldn't be thrown");
+            }
+        }
+
+        @Override
+        public boolean lowLevelCancellation() {
+            return true;
+        }
+    }
+
+    private static ContextIndexSearcher newContextSearcher(IndexReader reader, ExecutorService executor) throws IOException {
+        return new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            executor
+        );
+    }
+
+    private static ContextIndexSearcher newEarlyTerminationContextSearcher(IndexReader reader, int size, ExecutorService executor)
+        throws IOException {
+        return new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            executor
+        ) {
+
+            @Override
+            public void search(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
+                final Collector in = new AssertingEarlyTerminationFilterCollector(collector, size);
+                super.search(leaves, weight, in);
+            }
+        };
+    }
+
+    // used to check that numeric long or date sort optimization was run
+    private static ContextIndexSearcher newOptimizedContextSearcher(IndexReader reader, int queryType, ExecutorService executor)
+        throws IOException {
+        return new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            executor
+        ) {
+
+            @Override
+            public void search(
+                Query query,
+                CollectorManager<?, TopFieldDocs> manager,
+                QuerySearchResult result,
+                DocValueFormat[] formats,
+                TotalHits totalHits
+            ) throws IOException {
+                assertTrue(query instanceof BooleanQuery);
+                List<BooleanClause> clauses = ((BooleanQuery) query).clauses();
+                assertTrue(clauses.size() == 2);
+                assertTrue(clauses.get(0).getOccur() == Occur.FILTER);
+                assertTrue(clauses.get(1).getOccur() == Occur.SHOULD);
+                if (queryType == 0) {
+                    assertTrue(
+                        clauses.get(1).getQuery().getClass() == LongPoint.newDistanceFeatureQuery("random_field", 1, 1, 1).getClass()
+                    );
+                }
+                if (queryType == 1) assertTrue(clauses.get(1).getQuery() instanceof DocValuesFieldExistsQuery);
+                super.search(query, manager, result, formats, totalHits);
+            }
+
+            @Override
+            public void search(
+                List<LeafReaderContext> leaves,
+                Weight weight,
+                @SuppressWarnings("rawtypes") CollectorManager manager,
+                QuerySearchResult result,
+                DocValueFormat[] formats,
+                TotalHits totalHits
+            ) throws IOException {
+                final Query query = weight.getQuery();
+                assertTrue(query instanceof BooleanQuery);
+                List<BooleanClause> clauses = ((BooleanQuery) query).clauses();
+                assertTrue(clauses.size() == 2);
+                assertTrue(clauses.get(0).getOccur() == Occur.FILTER);
+                assertTrue(clauses.get(1).getOccur() == Occur.SHOULD);
+                if (queryType == 0) {
+                    assertTrue(
+                        clauses.get(1).getQuery().getClass() == LongPoint.newDistanceFeatureQuery("random_field", 1, 1, 1).getClass()
+                    );
+                }
+                if (queryType == 1) assertTrue(clauses.get(1).getQuery() instanceof DocValuesFieldExistsQuery);
+                super.search(leaves, weight, manager, result, formats, totalHits);
+            }
+
+            @Override
+            public void search(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
+                if (getExecutor() == null) {
+                    assert (false);  // should not be there, expected to search with CollectorManager
+                } else {
+                    super.search(leaves, weight, collector);
+                }
+            }
+        };
+    }
+
+    private static class TestTotalHitCountCollectorManager extends TotalHitCountCollectorManager {
+        private int totalHits;
+        private final TotalHitCountCollector collector;
+        private final Integer teminateAfter;
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor) {
+            return create(executor, null, null);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Integer teminateAfter) {
+            return create(executor, null, teminateAfter);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Sort sort) {
+            return create(executor, sort, null);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Sort sort, final Integer teminateAfter) {
+            if (executor == null) {
+                return new TestTotalHitCountCollectorManager(new TotalHitCountCollector(), sort);
+            } else {
+                return new TestTotalHitCountCollectorManager(sort, teminateAfter);
+            }
+        }
+
+        private TestTotalHitCountCollectorManager(final TotalHitCountCollector collector, final Sort sort) {
+            super(sort);
+            this.collector = collector;
+            this.teminateAfter = null;
+        }
+
+        private TestTotalHitCountCollectorManager(final Sort sort, final Integer teminateAfter) {
+            super(sort);
+            this.collector = null;
+            this.teminateAfter = teminateAfter;
+        }
+
+        @Override
+        public TotalHitCountCollector newCollector() throws IOException {
+            return (collector == null) ? super.newCollector() : collector;
+        }
+
+        @Override
+        public ReduceableSearchResult reduce(Collection<TotalHitCountCollector> collectors) throws IOException {
+            final ReduceableSearchResult result = super.reduce(collectors);
+            totalHits = collectors.stream().mapToInt(TotalHitCountCollector::getTotalHits).sum();
+
+            if (teminateAfter != null) {
+                assertThat(totalHits, greaterThanOrEqualTo(teminateAfter));
+                totalHits = Math.min(totalHits, teminateAfter);
+            }
+
+            return result;
+        }
+
+        public int getTotalHits() {
+            return (collector == null) ? totalHits : collector.getTotalHits();
+        }
+    }
+
+    private static class AssertingEarlyTerminationFilterCollector extends FilterCollector {
+        private final int size;
+
+        AssertingEarlyTerminationFilterCollector(Collector in, int size) {
+            super(in);
+            this.size = size;
+        }
+
+        @Override
+        public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
+            final LeafCollector in = super.getLeafCollector(context);
+            return new FilterLeafCollector(in) {
+                int collected;
+
+                @Override
+                public void collect(int doc) throws IOException {
+                    assert collected <= size : "should not collect more than " + size + " doc per segment, got " + collected;
+                    ++collected;
+                    super.collect(doc);
+                }
+            };
+        }
+    }
+}
diff --git a/scripts/build.sh b/scripts/build.sh
new file mode 100755
index 0000000000000..a0917776507be
--- /dev/null
+++ b/scripts/build.sh
@@ -0,0 +1,161 @@
+#!/bin/bash
+
+# Copyright OpenSearch Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+
+set -ex
+
+function usage() {
+    echo "Usage: $0 [args]"
+    echo ""
+    echo "Arguments:"
+    echo -e "-v VERSION\t[Required] OpenSearch version."
+    echo -e "-q QUALIFIER\t[Optional] Version qualifier."
+    echo -e "-s SNAPSHOT\t[Optional] Build a snapshot, default is 'false'."
+    echo -e "-p PLATFORM\t[Optional] Platform, default is 'uname -s'."
+    echo -e "-a ARCHITECTURE\t[Optional] Build architecture, default is 'uname -m'."
+    echo -e "-d DISTRIBUTION\t[Optional] Distribution, default is 'tar'."
+    echo -e "-o OUTPUT\t[Optional] Output path, default is 'artifacts'."
+    echo -e "-h help"
+}
+
+while getopts ":h:v:q:s:o:p:a:d:" arg; do
+    case $arg in
+        h)
+            usage
+            exit 1
+            ;;
+        v)
+            VERSION=$OPTARG
+            ;;
+        q)
+            QUALIFIER=$OPTARG
+            ;;
+        s)
+            SNAPSHOT=$OPTARG
+            ;;
+        o)
+            OUTPUT=$OPTARG
+            ;;
+        p)
+            PLATFORM=$OPTARG
+            ;;
+        a)
+            ARCHITECTURE=$OPTARG
+            ;;
+        d)
+            DISTRIBUTION=$OPTARG
+            ;;
+        :)
+            echo "Error: -${OPTARG} requires an argument"
+            usage
+            exit 1
+            ;;
+        ?)
+            echo "Invalid option: -${arg}"
+            exit 1
+            ;;
+    esac
+done
+
+if [ -z "$VERSION" ]; then
+    echo "Error: You must specify the OpenSearch version"
+    usage
+    exit 1
+fi
+
+[ -z "$OUTPUT" ] && OUTPUT=artifacts
+
+mkdir -p $OUTPUT/maven/org/opensearch
+
+# Build project and publish to maven local.
+./gradlew publishToMavenLocal -Dbuild.snapshot=$SNAPSHOT -Dbuild.version_qualifier=$QUALIFIER
+
+# Publish to existing test repo, using this to stage release versions of the artifacts that can be released from the same build.
+./gradlew publishNebulaPublicationToTestRepository -Dbuild.snapshot=$SNAPSHOT -Dbuild.version_qualifier=$QUALIFIER
+
+# Copy maven publications to be promoted
+cp -r ./build/local-test-repo/org/opensearch "${OUTPUT}"/maven/org
+
+# Assemble distribution artifact
+# see https://github.com/opensearch-project/OpenSearch/blob/main/settings.gradle#L34 for other distribution targets
+
+[ -z "$PLATFORM" ] && PLATFORM=$(uname -s | awk '{print tolower($0)}')
+[ -z "$ARCHITECTURE" ] && ARCHITECTURE=`uname -m`
+[ -z "$DISTRIBUTION" ] && DISTRIBUTION="tar"
+
+case $PLATFORM-$DISTRIBUTION-$ARCHITECTURE in
+    linux-tar-x64|darwin-tar-x64)
+        PACKAGE="tar"
+        EXT="tar.gz"
+        TYPE="archives"
+        TARGET="$PLATFORM-$PACKAGE"
+        SUFFIX="$PLATFORM-x64"
+        ;;
+    linux-tar-arm64|darwin-tar-arm64)
+        PACKAGE="tar"
+        EXT="tar.gz"
+        TYPE="archives"
+        TARGET="$PLATFORM-arm64-$PACKAGE"
+        SUFFIX="$PLATFORM-arm64"
+        ;;
+    linux-rpm-x64)
+        PACKAGE="rpm"
+        EXT="rpm"
+        TYPE="packages"
+        TARGET="rpm"
+        SUFFIX="x86_64"
+        ;;
+    linux-rpm-arm64)
+        PACKAGE="rpm"
+        EXT="rpm"
+        TYPE="packages"
+        TARGET="arm64-rpm"
+        SUFFIX="aarch64"
+        ;;
+    windows-zip-x64)
+        PACKAGE="zip"
+        EXT="zip"
+        TYPE="archives"
+        TARGET="$PLATFORM-$PACKAGE"
+        SUFFIX="$PLATFORM-x64"
+        ;;
+    windows-zip-arm64)
+        PACKAGE="zip"
+        EXT="zip"
+        TYPE="archives"
+        TARGET="$PLATFORM-arm64-$PACKAGE"
+        SUFFIX="$PLATFORM-arm64"
+        ;;
+    *)
+        echo "Unsupported platform-distribution-architecture combination: $PLATFORM-$DISTRIBUTION-$ARCHITECTURE"
+        exit 1
+        ;;
+esac
+
+echo "Building OpenSearch for $PLATFORM-$DISTRIBUTION-$ARCHITECTURE"
+
+./gradlew :distribution:$TYPE:$TARGET:assemble -Dbuild.snapshot=$SNAPSHOT -Dbuild.version_qualifier=$QUALIFIER
+
+# Copy artifact to dist folder in bundle build output
+[[ "$SNAPSHOT" == "true" ]] && IDENTIFIER="-SNAPSHOT"
+ARTIFACT_BUILD_NAME=`ls distribution/$TYPE/$TARGET/build/distributions/ | grep "opensearch-min.*$SUFFIX.$EXT"`
+mkdir -p "${OUTPUT}/dist"
+cp distribution/$TYPE/$TARGET/build/distributions/$ARTIFACT_BUILD_NAME "${OUTPUT}"/dist/$ARTIFACT_BUILD_NAME
+
+echo "Building core plugins..."
+mkdir -p "${OUTPUT}/core-plugins"
+cd plugins
+../gradlew assemble -Dbuild.snapshot="$SNAPSHOT" -Dbuild.version_qualifier=$QUALIFIER
+cd ..
+for plugin in plugins/*; do
+  PLUGIN_NAME=$(basename "$plugin")
+  if [ -d "$plugin" ] && [ "examples" != "$PLUGIN_NAME" ]; then
+    PLUGIN_ARTIFACT_BUILD_NAME=`ls "$plugin"/build/distributions/ | grep "$PLUGIN_NAME.*$IDENTIFIER.zip"`
+    cp "$plugin"/build/distributions/"$PLUGIN_ARTIFACT_BUILD_NAME" "${OUTPUT}"/core-plugins/"$PLUGIN_ARTIFACT_BUILD_NAME"
+  fi
+done
diff --git a/server/build.gradle b/server/build.gradle
index 45ec2300008f2..9c409d77363cb 100644
--- a/server/build.gradle
+++ b/server/build.gradle
@@ -30,21 +30,33 @@
 
 import org.opensearch.gradle.info.BuildParams
 
-apply plugin: 'opensearch.build'
-apply plugin: 'nebula.optional-base'
-apply plugin: 'opensearch.publish'
-apply plugin: 'opensearch.internal-cluster-test'
+plugins {
+  id('com.google.protobuf') version 'latest.release'
+  id('opensearch.build')
+  id('opensearch.publish')
+  id('opensearch.internal-cluster-test')
+  id('opensearch.optional-dependencies')
+}
 
 publishing {
   publications {
-    nebula {
+    nebula(MavenPublication) {
       artifactId 'opensearch'
     }
   }
 }
 
-archivesBaseName = 'opensearch'
+base {
+  archivesBaseName = 'opensearch'
+}
 
+sourceSets {
+  main {
+    java {
+      srcDir "${buildDir}/generated/source/proto/main/java"
+    }
+  }
+}
 // we want to keep the JDKs in our IDEs set to JDK 8 until minimum JDK is bumped to 11 so we do not include this source set in our IDEs
 if (!isEclipse) {
   sourceSets {
@@ -87,10 +99,14 @@ if (!isEclipse) {
 
 dependencies {
 
+  api project(':libs:opensearch-common')
   api project(':libs:opensearch-core')
+  api project(":libs:opensearch-compress")
   api project(':libs:opensearch-secure-sm')
   api project(':libs:opensearch-x-content')
   api project(":libs:opensearch-geo")
+  api project(":libs:opensearch-telemetry")
+
 
   compileOnly project(':libs:opensearch-plugin-classloader')
   testRuntimeOnly project(':libs:opensearch-plugin-classloader')
@@ -113,7 +129,6 @@ dependencies {
 
   // utilities
   api project(":libs:opensearch-cli")
-  api 'com.carrotsearch:hppc:0.8.1'
 
   // time handling, remove with java 8 time
   api "joda-time:joda-time:${versions.joda}"
@@ -121,7 +136,7 @@ dependencies {
   // percentiles aggregation
   api 'com.tdunning:t-digest:3.2'
   // precentil ranks aggregation
-  api 'org.hdrhistogram:HdrHistogram:2.1.9'
+  api 'org.hdrhistogram:HdrHistogram:2.1.12'
 
   // lucene spatial
   api "org.locationtech.spatial4j:spatial4j:${versions.spatial4j}", optional
@@ -129,11 +144,20 @@ dependencies {
 
   // logging
   api "org.apache.logging.log4j:log4j-api:${versions.log4j}"
+  api "org.apache.logging.log4j:log4j-jul:${versions.log4j}"
   api "org.apache.logging.log4j:log4j-core:${versions.log4j}", optional
+  annotationProcessor "org.apache.logging.log4j:log4j-core:${versions.log4j}"
 
   // jna
   api "net.java.dev.jna:jna:${versions.jna}"
 
+  // jcraft
+  api "com.jcraft:jzlib:${versions.jzlib}"
+
+  // protobuf
+  api "com.google.protobuf:protobuf-java:${versions.protobuf}"
+  api "jakarta.annotation:jakarta.annotation-api:${versions.jakarta_annotation}"
+
   testImplementation(project(":test:framework")) {
     // tests use the locally compiled version of server
     exclude group: 'org.opensearch', module: 'server'
@@ -149,33 +173,23 @@ tasks.withType(JavaCompile).configureEach {
   options.compilerArgs -= '-Xlint:unchecked'
 }
 
+compileJava {
+  options.compilerArgs += ['-processor', 'org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor']
+}
+
 tasks.named("internalClusterTest").configure {
   // TODO: these run faster with C2 only because they run for so, so long
   jvmArgs -= '-XX:TieredStopAtLevel=1'
 }
 
-// Until this project is always being formatted with spotless, we need to
-// guard against `spotless()` not existing.
-try {
-  spotless {
-    java {
-      // Contains large data tables that do not format well.
-      targetExclude 'src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlus.java'
-    }
-  }
-}
-catch (Exception e) {
-  if (e.getMessage().contains("Could not find method spotless") == false) {
-    throw e;
-  }
-}
-
 tasks.named("forbiddenPatterns").configure {
+    dependsOn("generateProto")
     exclude '**/*.json'
     exclude '**/*.jmx'
     exclude '**/*.dic'
     exclude '**/*.binary'
     exclude '**/*.st'
+    exclude '**/*.meta'
 }
 
 tasks.named("testingConventions").configure {
@@ -217,6 +231,22 @@ def generatePluginsList = tasks.register("generatePluginsList") {
     }
 }
 
+protobuf {
+  protoc {
+    artifact = "com.google.protobuf:protoc:${versions.protobuf}"
+  }
+
+  generateProtoTasks {
+    all().each { task ->
+      task.builtins {
+        java {
+          option "annotate_code"
+        }
+      }
+    }
+  }
+}
+
 tasks.named("processResources").configure {
     dependsOn generateModulesList, generatePluginsList
 }
@@ -258,7 +288,9 @@ tasks.named("thirdPartyAudit").configure {
             'com.lmax.disruptor.LifecycleAware',
             'com.lmax.disruptor.RingBuffer',
             'com.lmax.disruptor.Sequence',
+            'com.lmax.disruptor.SequenceBarrier',
             'com.lmax.disruptor.SequenceReportingEventHandler',
+            'com.lmax.disruptor.TimeoutException',
             'com.lmax.disruptor.WaitStrategy',
             'com.lmax.disruptor.dsl.Disruptor',
             'com.lmax.disruptor.dsl.ProducerType',
@@ -287,6 +319,7 @@ tasks.named("thirdPartyAudit").configure {
             'org.apache.commons.csv.QuoteMode',
             'org.apache.kafka.clients.producer.Producer',
             'org.apache.kafka.clients.producer.RecordMetadata',
+            'org.apache.kafka.common.serialization.ByteArraySerializer',
             'org.codehaus.stax2.XMLStreamWriter2',
             'org.jctools.queues.MpscArrayQueue',
             'org.osgi.framework.Bundle',
@@ -295,6 +328,7 @@ tasks.named("thirdPartyAudit").configure {
             'org.osgi.framework.BundleEvent',
             'org.osgi.framework.BundleReference',
             'org.osgi.framework.FrameworkUtil',
+            'org.osgi.framework.ServiceReference',
             'org.osgi.framework.ServiceRegistration',
             'org.osgi.framework.SynchronousBundleListener',
             'org.osgi.framework.wiring.BundleWire',
@@ -317,10 +351,15 @@ tasks.named("thirdPartyAudit").configure {
             'com.google.common.geometry.S2$Metric',
             'com.google.common.geometry.S2LatLng'
     )
-
-    if (BuildParams.runtimeJavaVersion > JavaVersion.VERSION_1_8) {
-        ignoreMissingClasses 'javax.xml.bind.DatatypeConverter'
-    }
+    ignoreViolations(
+            'com.google.protobuf.MessageSchema',
+            'com.google.protobuf.UnsafeUtil',
+            'com.google.protobuf.UnsafeUtil$1',
+            'com.google.protobuf.UnsafeUtil$Android32MemoryAccessor',
+            'com.google.protobuf.UnsafeUtil$Android64MemoryAccessor',
+            'com.google.protobuf.UnsafeUtil$JvmMemoryAccessor',
+            'com.google.protobuf.UnsafeUtil$MemoryAccessor'
+    )
 }
 
 tasks.named("dependencyLicenses").configure {
@@ -333,13 +372,20 @@ tasks.named("dependencyLicenses").configure {
     }
 }
 
+tasks.named("filepermissions").configure {
+  mustRunAfter("generateProto")
+}
+
 tasks.named("licenseHeaders").configure {
+    dependsOn("generateProto")
     // Ignore our vendored version of Google Guice
     excludes << 'org/opensearch/common/inject/**/*'
     // Ignore temporary copies of impending 8.7 Lucene classes
     excludes << 'org/apache/lucene/search/RegExp87*'
     excludes << 'org/apache/lucene/search/RegexpQuery87*'
     excludes << 'org/opensearch/client/documentation/placeholder.txt'
+    // Ignore for protobuf generated code
+    excludes << 'org/opensearch/extensions/proto/*'
 }
 
 tasks.test {
@@ -347,3 +393,10 @@ tasks.test {
         jvmArgs += ["--add-opens", "java.base/java.nio.file=ALL-UNNAMED"]
     }
 }
+
+tasks.named("sourcesJar").configure {
+  // Ignore duplicates for protobuf generated code (main and generatedSources).
+  filesMatching("**/proto/*") {
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+  }
+}
diff --git a/server/licenses/HdrHistogram-2.1.12.jar.sha1 b/server/licenses/HdrHistogram-2.1.12.jar.sha1
new file mode 100644
index 0000000000000..9d20fa0e5f22d
--- /dev/null
+++ b/server/licenses/HdrHistogram-2.1.12.jar.sha1
@@ -0,0 +1 @@
+6eb7552156e0d517ae80cc2247be1427c8d90452
\ No newline at end of file
diff --git a/server/licenses/HdrHistogram-2.1.9.jar.sha1 b/server/licenses/HdrHistogram-2.1.9.jar.sha1
deleted file mode 100644
index 2378df07b2c0c..0000000000000
--- a/server/licenses/HdrHistogram-2.1.9.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-e4631ce165eb400edecfa32e03d3f1be53dee754
\ No newline at end of file
diff --git a/server/licenses/hppc-0.8.1.jar.sha1 b/server/licenses/hppc-0.8.1.jar.sha1
deleted file mode 100644
index 47684ed023210..0000000000000
--- a/server/licenses/hppc-0.8.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-ffc7ba8f289428b9508ab484b8001dea944ae603
\ No newline at end of file
diff --git a/server/licenses/hppc-LICENSE.txt b/server/licenses/hppc-LICENSE.txt
deleted file mode 100644
index 31467575cdbfe..0000000000000
--- a/server/licenses/hppc-LICENSE.txt
+++ /dev/null
@@ -1,203 +0,0 @@
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright 2010-2013, Carrot Search s.c., Boznicza 11/56, Poznan, Poland
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
diff --git a/server/licenses/hppc-NOTICE.txt b/server/licenses/hppc-NOTICE.txt
deleted file mode 100644
index 1d8842c0bc69d..0000000000000
--- a/server/licenses/hppc-NOTICE.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-ACKNOWLEDGEMENT
-===============
-
-HPPC borrowed code, ideas or both from:
-
- * Apache Lucene, http://lucene.apache.org/
-   (Apache license)
- * Fastutil, http://fastutil.di.unimi.it/
-   (Apache license)
- * Koloboke, https://github.com/OpenHFT/Koloboke
-   (Apache license)
diff --git a/server/licenses/jakarta.annotation-api-1.3.5.jar.sha1 b/server/licenses/jakarta.annotation-api-1.3.5.jar.sha1
new file mode 100644
index 0000000000000..da07243fcc79f
--- /dev/null
+++ b/server/licenses/jakarta.annotation-api-1.3.5.jar.sha1
@@ -0,0 +1 @@
+59eb84ee0d616332ff44aba065f3888cf002cd2d
\ No newline at end of file
diff --git a/server/licenses/jakarta.annotation-api-LICENSE.txt b/server/licenses/jakarta.annotation-api-LICENSE.txt
new file mode 100644
index 0000000000000..b021839cdf874
--- /dev/null
+++ b/server/licenses/jakarta.annotation-api-LICENSE.txt
@@ -0,0 +1,637 @@
+# Eclipse Public License - v 2.0
+
+        THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE
+        PUBLIC LICENSE ("AGREEMENT"). ANY USE, REPRODUCTION OR DISTRIBUTION
+        OF THE PROGRAM CONSTITUTES RECIPIENT'S ACCEPTANCE OF THIS AGREEMENT.
+
+    1. DEFINITIONS
+
+    "Contribution" means:
+
+      a) in the case of the initial Contributor, the initial content
+         Distributed under this Agreement, and
+
+      b) in the case of each subsequent Contributor: 
+         i) changes to the Program, and 
+         ii) additions to the Program;
+      where such changes and/or additions to the Program originate from
+      and are Distributed by that particular Contributor. A Contribution
+      "originates" from a Contributor if it was added to the Program by
+      such Contributor itself or anyone acting on such Contributor's behalf.
+      Contributions do not include changes or additions to the Program that
+      are not Modified Works.
+
+    "Contributor" means any person or entity that Distributes the Program.
+
+    "Licensed Patents" mean patent claims licensable by a Contributor which
+    are necessarily infringed by the use or sale of its Contribution alone
+    or when combined with the Program.
+
+    "Program" means the Contributions Distributed in accordance with this
+    Agreement.
+
+    "Recipient" means anyone who receives the Program under this Agreement
+    or any Secondary License (as applicable), including Contributors.
+
+    "Derivative Works" shall mean any work, whether in Source Code or other
+    form, that is based on (or derived from) the Program and for which the
+    editorial revisions, annotations, elaborations, or other modifications
+    represent, as a whole, an original work of authorship.
+
+    "Modified Works" shall mean any work in Source Code or other form that
+    results from an addition to, deletion from, or modification of the
+    contents of the Program, including, for purposes of clarity any new file
+    in Source Code form that contains any contents of the Program. Modified
+    Works shall not include works that contain only declarations,
+    interfaces, types, classes, structures, or files of the Program solely
+    in each case in order to link to, bind by name, or subclass the Program
+    or Modified Works thereof.
+
+    "Distribute" means the acts of a) distributing or b) making available
+    in any manner that enables the transfer of a copy.
+
+    "Source Code" means the form of a Program preferred for making
+    modifications, including but not limited to software source code,
+    documentation source, and configuration files.
+
+    "Secondary License" means either the GNU General Public License,
+    Version 2.0, or any later versions of that license, including any
+    exceptions or additional permissions as identified by the initial
+    Contributor.
+
+    2. GRANT OF RIGHTS
+
+      a) Subject to the terms of this Agreement, each Contributor hereby
+      grants Recipient a non-exclusive, worldwide, royalty-free copyright
+      license to reproduce, prepare Derivative Works of, publicly display,
+      publicly perform, Distribute and sublicense the Contribution of such
+      Contributor, if any, and such Derivative Works.
+
+      b) Subject to the terms of this Agreement, each Contributor hereby
+      grants Recipient a non-exclusive, worldwide, royalty-free patent
+      license under Licensed Patents to make, use, sell, offer to sell,
+      import and otherwise transfer the Contribution of such Contributor,
+      if any, in Source Code or other form. This patent license shall
+      apply to the combination of the Contribution and the Program if, at
+      the time the Contribution is added by the Contributor, such addition
+      of the Contribution causes such combination to be covered by the
+      Licensed Patents. The patent license shall not apply to any other
+      combinations which include the Contribution. No hardware per se is
+      licensed hereunder.
+
+      c) Recipient understands that although each Contributor grants the
+      licenses to its Contributions set forth herein, no assurances are
+      provided by any Contributor that the Program does not infringe the
+      patent or other intellectual property rights of any other entity.
+      Each Contributor disclaims any liability to Recipient for claims
+      brought by any other entity based on infringement of intellectual
+      property rights or otherwise. As a condition to exercising the
+      rights and licenses granted hereunder, each Recipient hereby
+      assumes sole responsibility to secure any other intellectual
+      property rights needed, if any. For example, if a third party
+      patent license is required to allow Recipient to Distribute the
+      Program, it is Recipient's responsibility to acquire that license
+      before distributing the Program.
+
+      d) Each Contributor represents that to its knowledge it has
+      sufficient copyright rights in its Contribution, if any, to grant
+      the copyright license set forth in this Agreement.
+
+      e) Notwithstanding the terms of any Secondary License, no
+      Contributor makes additional grants to any Recipient (other than
+      those set forth in this Agreement) as a result of such Recipient's
+      receipt of the Program under the terms of a Secondary License
+      (if permitted under the terms of Section 3).
+
+    3. REQUIREMENTS
+
+    3.1 If a Contributor Distributes the Program in any form, then:
+
+      a) the Program must also be made available as Source Code, in
+      accordance with section 3.2, and the Contributor must accompany
+      the Program with a statement that the Source Code for the Program
+      is available under this Agreement, and informs Recipients how to
+      obtain it in a reasonable manner on or through a medium customarily
+      used for software exchange; and
+
+      b) the Contributor may Distribute the Program under a license
+      different than this Agreement, provided that such license:
+         i) effectively disclaims on behalf of all other Contributors all
+         warranties and conditions, express and implied, including
+         warranties or conditions of title and non-infringement, and
+         implied warranties or conditions of merchantability and fitness
+         for a particular purpose;
+
+         ii) effectively excludes on behalf of all other Contributors all
+         liability for damages, including direct, indirect, special,
+         incidental and consequential damages, such as lost profits;
+
+         iii) does not attempt to limit or alter the recipients' rights
+         in the Source Code under section 3.2; and
+
+         iv) requires any subsequent distribution of the Program by any
+         party to be under a license that satisfies the requirements
+         of this section 3.
+
+    3.2 When the Program is Distributed as Source Code:
+
+      a) it must be made available under this Agreement, or if the
+      Program (i) is combined with other material in a separate file or
+      files made available under a Secondary License, and (ii) the initial
+      Contributor attached to the Source Code the notice described in
+      Exhibit A of this Agreement, then the Program may be made available
+      under the terms of such Secondary Licenses, and
+
+      b) a copy of this Agreement must be included with each copy of
+      the Program.
+
+    3.3 Contributors may not remove or alter any copyright, patent,
+    trademark, attribution notices, disclaimers of warranty, or limitations
+    of liability ("notices") contained within the Program from any copy of
+    the Program which they Distribute, provided that Contributors may add
+    their own appropriate notices.
+
+    4. COMMERCIAL DISTRIBUTION
+
+    Commercial distributors of software may accept certain responsibilities
+    with respect to end users, business partners and the like. While this
+    license is intended to facilitate the commercial use of the Program,
+    the Contributor who includes the Program in a commercial product
+    offering should do so in a manner which does not create potential
+    liability for other Contributors. Therefore, if a Contributor includes
+    the Program in a commercial product offering, such Contributor
+    ("Commercial Contributor") hereby agrees to defend and indemnify every
+    other Contributor ("Indemnified Contributor") against any losses,
+    damages and costs (collectively "Losses") arising from claims, lawsuits
+    and other legal actions brought by a third party against the Indemnified
+    Contributor to the extent caused by the acts or omissions of such
+    Commercial Contributor in connection with its distribution of the Program
+    in a commercial product offering. The obligations in this section do not
+    apply to any claims or Losses relating to any actual or alleged
+    intellectual property infringement. In order to qualify, an Indemnified
+    Contributor must: a) promptly notify the Commercial Contributor in
+    writing of such claim, and b) allow the Commercial Contributor to control,
+    and cooperate with the Commercial Contributor in, the defense and any
+    related settlement negotiations. The Indemnified Contributor may
+    participate in any such claim at its own expense.
+
+    For example, a Contributor might include the Program in a commercial
+    product offering, Product X. That Contributor is then a Commercial
+    Contributor. If that Commercial Contributor then makes performance
+    claims, or offers warranties related to Product X, those performance
+    claims and warranties are such Commercial Contributor's responsibility
+    alone. Under this section, the Commercial Contributor would have to
+    defend claims against the other Contributors related to those performance
+    claims and warranties, and if a court requires any other Contributor to
+    pay any damages as a result, the Commercial Contributor must pay
+    those damages.
+
+    5. NO WARRANTY
+
+    EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, AND TO THE EXTENT
+    PERMITTED BY APPLICABLE LAW, THE PROGRAM IS PROVIDED ON AN "AS IS"
+    BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, EITHER EXPRESS OR
+    IMPLIED INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OR CONDITIONS OF
+    TITLE, NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR
+    PURPOSE. Each Recipient is solely responsible for determining the
+    appropriateness of using and distributing the Program and assumes all
+    risks associated with its exercise of rights under this Agreement,
+    including but not limited to the risks and costs of program errors,
+    compliance with applicable laws, damage to or loss of data, programs
+    or equipment, and unavailability or interruption of operations.
+
+    6. DISCLAIMER OF LIABILITY
+
+    EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, AND TO THE EXTENT
+    PERMITTED BY APPLICABLE LAW, NEITHER RECIPIENT NOR ANY CONTRIBUTORS
+    SHALL HAVE ANY LIABILITY FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING WITHOUT LIMITATION LOST
+    PROFITS), HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+    ARISING IN ANY WAY OUT OF THE USE OR DISTRIBUTION OF THE PROGRAM OR THE
+    EXERCISE OF ANY RIGHTS GRANTED HEREUNDER, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGES.
+
+    7. GENERAL
+
+    If any provision of this Agreement is invalid or unenforceable under
+    applicable law, it shall not affect the validity or enforceability of
+    the remainder of the terms of this Agreement, and without further
+    action by the parties hereto, such provision shall be reformed to the
+    minimum extent necessary to make such provision valid and enforceable.
+
+    If Recipient institutes patent litigation against any entity
+    (including a cross-claim or counterclaim in a lawsuit) alleging that the
+    Program itself (excluding combinations of the Program with other software
+    or hardware) infringes such Recipient's patent(s), then such Recipient's
+    rights granted under Section 2(b) shall terminate as of the date such
+    litigation is filed.
+
+    All Recipient's rights under this Agreement shall terminate if it
+    fails to comply with any of the material terms or conditions of this
+    Agreement and does not cure such failure in a reasonable period of
+    time after becoming aware of such noncompliance. If all Recipient's
+    rights under this Agreement terminate, Recipient agrees to cease use
+    and distribution of the Program as soon as reasonably practicable.
+    However, Recipient's obligations under this Agreement and any licenses
+    granted by Recipient relating to the Program shall continue and survive.
+
+    Everyone is permitted to copy and distribute copies of this Agreement,
+    but in order to avoid inconsistency the Agreement is copyrighted and
+    may only be modified in the following manner. The Agreement Steward
+    reserves the right to publish new versions (including revisions) of
+    this Agreement from time to time. No one other than the Agreement
+    Steward has the right to modify this Agreement. The Eclipse Foundation
+    is the initial Agreement Steward. The Eclipse Foundation may assign the
+    responsibility to serve as the Agreement Steward to a suitable separate
+    entity. Each new version of the Agreement will be given a distinguishing
+    version number. The Program (including Contributions) may always be
+    Distributed subject to the version of the Agreement under which it was
+    received. In addition, after a new version of the Agreement is published,
+    Contributor may elect to Distribute the Program (including its
+    Contributions) under the new version.
+
+    Except as expressly stated in Sections 2(a) and 2(b) above, Recipient
+    receives no rights or licenses to the intellectual property of any
+    Contributor under this Agreement, whether expressly, by implication,
+    estoppel or otherwise. All rights in the Program not expressly granted
+    under this Agreement are reserved. Nothing in this Agreement is intended
+    to be enforceable by any entity that is not a Contributor or Recipient.
+    No third-party beneficiary rights are created under this Agreement.
+
+    Exhibit A - Form of Secondary Licenses Notice
+
+    "This Source Code may also be made available under the following 
+    Secondary Licenses when the conditions for such availability set forth 
+    in the Eclipse Public License, v. 2.0 are satisfied: {name license(s),
+    version(s), and exceptions or additional permissions here}."
+
+      Simply including a copy of this Agreement, including this Exhibit A
+      is not sufficient to license the Source Code under Secondary Licenses.
+
+      If it is not possible or desirable to put the notice in a particular
+      file, then You may include the notice in a location (such as a LICENSE
+      file in a relevant directory) where a recipient would be likely to
+      look for such a notice.
+
+      You may add additional accurate notices of copyright ownership.
+
+---
+
+##    The GNU General Public License (GPL) Version 2, June 1991
+
+    Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+    51 Franklin Street, Fifth Floor
+    Boston, MA 02110-1335
+    USA
+
+    Everyone is permitted to copy and distribute verbatim copies
+    of this license document, but changing it is not allowed.
+
+    Preamble
+
+    The licenses for most software are designed to take away your freedom to
+    share and change it. By contrast, the GNU General Public License is
+    intended to guarantee your freedom to share and change free software--to
+    make sure the software is free for all its users. This General Public
+    License applies to most of the Free Software Foundation's software and
+    to any other program whose authors commit to using it. (Some other Free
+    Software Foundation software is covered by the GNU Library General
+    Public License instead.) You can apply it to your programs, too.
+
+    When we speak of free software, we are referring to freedom, not price.
+    Our General Public Licenses are designed to make sure that you have the
+    freedom to distribute copies of free software (and charge for this
+    service if you wish), that you receive source code or can get it if you
+    want it, that you can change the software or use pieces of it in new
+    free programs; and that you know you can do these things.
+
+    To protect your rights, we need to make restrictions that forbid anyone
+    to deny you these rights or to ask you to surrender the rights. These
+    restrictions translate to certain responsibilities for you if you
+    distribute copies of the software, or if you modify it.
+
+    For example, if you distribute copies of such a program, whether gratis
+    or for a fee, you must give the recipients all the rights that you have.
+    You must make sure that they, too, receive or can get the source code.
+    And you must show them these terms so they know their rights.
+
+    We protect your rights with two steps: (1) copyright the software, and
+    (2) offer you this license which gives you legal permission to copy,
+    distribute and/or modify the software.
+
+    Also, for each author's protection and ours, we want to make certain
+    that everyone understands that there is no warranty for this free
+    software. If the software is modified by someone else and passed on, we
+    want its recipients to know that what they have is not the original, so
+    that any problems introduced by others will not reflect on the original
+    authors' reputations.
+
+    Finally, any free program is threatened constantly by software patents.
+    We wish to avoid the danger that redistributors of a free program will
+    individually obtain patent licenses, in effect making the program
+    proprietary. To prevent this, we have made it clear that any patent must
+    be licensed for everyone's free use or not licensed at all.
+
+    The precise terms and conditions for copying, distribution and
+    modification follow.
+
+    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+    0. This License applies to any program or other work which contains a
+    notice placed by the copyright holder saying it may be distributed under
+    the terms of this General Public License. The "Program", below, refers
+    to any such program or work, and a "work based on the Program" means
+    either the Program or any derivative work under copyright law: that is
+    to say, a work containing the Program or a portion of it, either
+    verbatim or with modifications and/or translated into another language.
+    (Hereinafter, translation is included without limitation in the term
+    "modification".) Each licensee is addressed as "you".
+
+    Activities other than copying, distribution and modification are not
+    covered by this License; they are outside its scope. The act of running
+    the Program is not restricted, and the output from the Program is
+    covered only if its contents constitute a work based on the Program
+    (independent of having been made by running the Program). Whether that
+    is true depends on what the Program does.
+
+    1. You may copy and distribute verbatim copies of the Program's source
+    code as you receive it, in any medium, provided that you conspicuously
+    and appropriately publish on each copy an appropriate copyright notice
+    and disclaimer of warranty; keep intact all the notices that refer to
+    this License and to the absence of any warranty; and give any other
+    recipients of the Program a copy of this License along with the Program.
+
+    You may charge a fee for the physical act of transferring a copy, and
+    you may at your option offer warranty protection in exchange for a fee.
+
+    2. You may modify your copy or copies of the Program or any portion of
+    it, thus forming a work based on the Program, and copy and distribute
+    such modifications or work under the terms of Section 1 above, provided
+    that you also meet all of these conditions:
+
+        a) You must cause the modified files to carry prominent notices
+        stating that you changed the files and the date of any change.
+
+        b) You must cause any work that you distribute or publish, that in
+        whole or in part contains or is derived from the Program or any part
+        thereof, to be licensed as a whole at no charge to all third parties
+        under the terms of this License.
+
+        c) If the modified program normally reads commands interactively
+        when run, you must cause it, when started running for such
+        interactive use in the most ordinary way, to print or display an
+        announcement including an appropriate copyright notice and a notice
+        that there is no warranty (or else, saying that you provide a
+        warranty) and that users may redistribute the program under these
+        conditions, and telling the user how to view a copy of this License.
+        (Exception: if the Program itself is interactive but does not
+        normally print such an announcement, your work based on the Program
+        is not required to print an announcement.)
+
+    These requirements apply to the modified work as a whole. If
+    identifiable sections of that work are not derived from the Program, and
+    can be reasonably considered independent and separate works in
+    themselves, then this License, and its terms, do not apply to those
+    sections when you distribute them as separate works. But when you
+    distribute the same sections as part of a whole which is a work based on
+    the Program, the distribution of the whole must be on the terms of this
+    License, whose permissions for other licensees extend to the entire
+    whole, and thus to each and every part regardless of who wrote it.
+
+    Thus, it is not the intent of this section to claim rights or contest
+    your rights to work written entirely by you; rather, the intent is to
+    exercise the right to control the distribution of derivative or
+    collective works based on the Program.
+
+    In addition, mere aggregation of another work not based on the Program
+    with the Program (or with a work based on the Program) on a volume of a
+    storage or distribution medium does not bring the other work under the
+    scope of this License.
+
+    3. You may copy and distribute the Program (or a work based on it,
+    under Section 2) in object code or executable form under the terms of
+    Sections 1 and 2 above provided that you also do one of the following:
+
+        a) Accompany it with the complete corresponding machine-readable
+        source code, which must be distributed under the terms of Sections 1
+        and 2 above on a medium customarily used for software interchange; or,
+
+        b) Accompany it with a written offer, valid for at least three
+        years, to give any third party, for a charge no more than your cost
+        of physically performing source distribution, a complete
+        machine-readable copy of the corresponding source code, to be
+        distributed under the terms of Sections 1 and 2 above on a medium
+        customarily used for software interchange; or,
+
+        c) Accompany it with the information you received as to the offer to
+        distribute corresponding source code. (This alternative is allowed
+        only for noncommercial distribution and only if you received the
+        program in object code or executable form with such an offer, in
+        accord with Subsection b above.)
+
+    The source code for a work means the preferred form of the work for
+    making modifications to it. For an executable work, complete source code
+    means all the source code for all modules it contains, plus any
+    associated interface definition files, plus the scripts used to control
+    compilation and installation of the executable. However, as a special
+    exception, the source code distributed need not include anything that is
+    normally distributed (in either source or binary form) with the major
+    components (compiler, kernel, and so on) of the operating system on
+    which the executable runs, unless that component itself accompanies the
+    executable.
+
+    If distribution of executable or object code is made by offering access
+    to copy from a designated place, then offering equivalent access to copy
+    the source code from the same place counts as distribution of the source
+    code, even though third parties are not compelled to copy the source
+    along with the object code.
+
+    4. You may not copy, modify, sublicense, or distribute the Program
+    except as expressly provided under this License. Any attempt otherwise
+    to copy, modify, sublicense or distribute the Program is void, and will
+    automatically terminate your rights under this License. However, parties
+    who have received copies, or rights, from you under this License will
+    not have their licenses terminated so long as such parties remain in
+    full compliance.
+
+    5. You are not required to accept this License, since you have not
+    signed it. However, nothing else grants you permission to modify or
+    distribute the Program or its derivative works. These actions are
+    prohibited by law if you do not accept this License. Therefore, by
+    modifying or distributing the Program (or any work based on the
+    Program), you indicate your acceptance of this License to do so, and all
+    its terms and conditions for copying, distributing or modifying the
+    Program or works based on it.
+
+    6. Each time you redistribute the Program (or any work based on the
+    Program), the recipient automatically receives a license from the
+    original licensor to copy, distribute or modify the Program subject to
+    these terms and conditions. You may not impose any further restrictions
+    on the recipients' exercise of the rights granted herein. You are not
+    responsible for enforcing compliance by third parties to this License.
+
+    7. If, as a consequence of a court judgment or allegation of patent
+    infringement or for any other reason (not limited to patent issues),
+    conditions are imposed on you (whether by court order, agreement or
+    otherwise) that contradict the conditions of this License, they do not
+    excuse you from the conditions of this License. If you cannot distribute
+    so as to satisfy simultaneously your obligations under this License and
+    any other pertinent obligations, then as a consequence you may not
+    distribute the Program at all. For example, if a patent license would
+    not permit royalty-free redistribution of the Program by all those who
+    receive copies directly or indirectly through you, then the only way you
+    could satisfy both it and this License would be to refrain entirely from
+    distribution of the Program.
+
+    If any portion of this section is held invalid or unenforceable under
+    any particular circumstance, the balance of the section is intended to
+    apply and the section as a whole is intended to apply in other
+    circumstances.
+
+    It is not the purpose of this section to induce you to infringe any
+    patents or other property right claims or to contest validity of any
+    such claims; this section has the sole purpose of protecting the
+    integrity of the free software distribution system, which is implemented
+    by public license practices. Many people have made generous
+    contributions to the wide range of software distributed through that
+    system in reliance on consistent application of that system; it is up to
+    the author/donor to decide if he or she is willing to distribute
+    software through any other system and a licensee cannot impose that choice.
+
+    This section is intended to make thoroughly clear what is believed to be
+    a consequence of the rest of this License.
+
+    8. If the distribution and/or use of the Program is restricted in
+    certain countries either by patents or by copyrighted interfaces, the
+    original copyright holder who places the Program under this License may
+    add an explicit geographical distribution limitation excluding those
+    countries, so that distribution is permitted only in or among countries
+    not thus excluded. In such case, this License incorporates the
+    limitation as if written in the body of this License.
+
+    9. The Free Software Foundation may publish revised and/or new
+    versions of the General Public License from time to time. Such new
+    versions will be similar in spirit to the present version, but may
+    differ in detail to address new problems or concerns.
+
+    Each version is given a distinguishing version number. If the Program
+    specifies a version number of this License which applies to it and "any
+    later version", you have the option of following the terms and
+    conditions either of that version or of any later version published by
+    the Free Software Foundation. If the Program does not specify a version
+    number of this License, you may choose any version ever published by the
+    Free Software Foundation.
+
+    10. If you wish to incorporate parts of the Program into other free
+    programs whose distribution conditions are different, write to the
+    author to ask for permission. For software which is copyrighted by the
+    Free Software Foundation, write to the Free Software Foundation; we
+    sometimes make exceptions for this. Our decision will be guided by the
+    two goals of preserving the free status of all derivatives of our free
+    software and of promoting the sharing and reuse of software generally.
+
+    NO WARRANTY
+
+    11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
+    WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
+    EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
+    OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND,
+    EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
+    ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH
+    YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
+    NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+    12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
+    WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
+    AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR
+    DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL
+    DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM
+    (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
+    INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF
+    THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR
+    OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+
+    END OF TERMS AND CONDITIONS
+
+    How to Apply These Terms to Your New Programs
+
+    If you develop a new program, and you want it to be of the greatest
+    possible use to the public, the best way to achieve this is to make it
+    free software which everyone can redistribute and change under these terms.
+
+    To do so, attach the following notices to the program. It is safest to
+    attach them to the start of each source file to most effectively convey
+    the exclusion of warranty; and each file should have at least the
+    "copyright" line and a pointer to where the full notice is found.
+
+        One line to give the program's name and a brief idea of what it does.
+        Copyright (C) <year> <name of author>
+
+        This program is free software; you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation; either version 2 of the License, or
+        (at your option) any later version.
+
+        This program is distributed in the hope that it will be useful, but
+        WITHOUT ANY WARRANTY; without even the implied warranty of
+        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+        General Public License for more details.
+
+        You should have received a copy of the GNU General Public License
+        along with this program; if not, write to the Free Software
+        Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
+
+    Also add information on how to contact you by electronic and paper mail.
+
+    If the program is interactive, make it output a short notice like this
+    when it starts in an interactive mode:
+
+        Gnomovision version 69, Copyright (C) year name of author
+        Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type
+        `show w'. This is free software, and you are welcome to redistribute
+        it under certain conditions; type `show c' for details.
+
+    The hypothetical commands `show w' and `show c' should show the
+    appropriate parts of the General Public License. Of course, the commands
+    you use may be called something other than `show w' and `show c'; they
+    could even be mouse-clicks or menu items--whatever suits your program.
+
+    You should also get your employer (if you work as a programmer) or your
+    school, if any, to sign a "copyright disclaimer" for the program, if
+    necessary. Here is a sample; alter the names:
+
+        Yoyodyne, Inc., hereby disclaims all copyright interest in the
+        program `Gnomovision' (which makes passes at compilers) written by
+        James Hacker.
+
+        signature of Ty Coon, 1 April 1989
+        Ty Coon, President of Vice
+
+    This General Public License does not permit incorporating your program
+    into proprietary programs. If your program is a subroutine library, you
+    may consider it more useful to permit linking proprietary applications
+    with the library. If this is what you want to do, use the GNU Library
+    General Public License instead of this License.
+
+---
+
+## CLASSPATH EXCEPTION
+
+    Linking this library statically or dynamically with other modules is
+    making a combined work based on this library.  Thus, the terms and
+    conditions of the GNU General Public License version 2 cover the whole
+    combination.
+
+    As a special exception, the copyright holders of this library give you
+    permission to link this library with independent modules to produce an
+    executable, regardless of the license terms of these independent
+    modules, and to copy and distribute the resulting executable under
+    terms of your choice, provided that you also meet, for each linked
+    independent module, the terms and conditions of the license of that
+    module.  An independent module is a module which is not derived from or
+    based on this library.  If you modify this library, you may extend this
+    exception to your version of the library, but you are not obligated to
+    do so.  If you do not wish to do so, delete this exception statement
+    from your version.
\ No newline at end of file
diff --git a/server/licenses/jakarta.annotation-api-NOTICE.txt b/server/licenses/jakarta.annotation-api-NOTICE.txt
new file mode 100644
index 0000000000000..8e60c4b1b80c5
--- /dev/null
+++ b/server/licenses/jakarta.annotation-api-NOTICE.txt
@@ -0,0 +1,38 @@
+# Notices for Jakarta Annotations
+
+This content is produced and maintained by the Jakarta Annotations project.
+
+ * Project home: https://projects.eclipse.org/projects/ee4j.ca
+
+## Trademarks
+
+Jakarta Annotations is a trademark of the Eclipse Foundation.
+
+## Declared Project Licenses
+
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License v. 2.0 which is available at
+http://www.eclipse.org/legal/epl-2.0. This Source Code may also be made
+available under the following Secondary Licenses when the conditions for such
+availability set forth in the Eclipse Public License v. 2.0 are satisfied: GNU
+General Public License, version 2 with the GNU Classpath Exception which is
+available at https://www.gnu.org/software/classpath/license.html.
+
+SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+
+## Source Code
+
+The project maintains the following source code repositories:
+
+ * https://github.com/eclipse-ee4j/common-annotations-api
+
+## Third-party Content
+
+## Cryptography
+
+Content may contain encryption software. The country in which you are currently
+may have restrictions on the import, possession, and use, and/or re-export to
+another country, of encryption software. BEFORE using any encryption software,
+please check the country's laws, regulations and policies concerning the import,
+possession, or use, and re-export of encryption software, to see if this is
+permitted.
\ No newline at end of file
diff --git a/server/licenses/jna-5.13.0.jar.sha1 b/server/licenses/jna-5.13.0.jar.sha1
new file mode 100644
index 0000000000000..faf2012f0b5c0
--- /dev/null
+++ b/server/licenses/jna-5.13.0.jar.sha1
@@ -0,0 +1 @@
+1200e7ebeedbe0d10062093f32925a912020e747
\ No newline at end of file
diff --git a/server/licenses/jna-5.5.0.jar.sha1 b/server/licenses/jna-5.5.0.jar.sha1
deleted file mode 100644
index 5621dfc743dd0..0000000000000
--- a/server/licenses/jna-5.5.0.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-0e0845217c4907822403912ad6828d8e0b256208
diff --git a/server/licenses/joda-time-2.10.12.jar.sha1 b/server/licenses/joda-time-2.10.12.jar.sha1
deleted file mode 100644
index 538f23152f69d..0000000000000
--- a/server/licenses/joda-time-2.10.12.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-95b3f193ad0493d94dcd7daa9ea575c30e6be5f5
\ No newline at end of file
diff --git a/server/licenses/joda-time-2.12.2.jar.sha1 b/server/licenses/joda-time-2.12.2.jar.sha1
new file mode 100644
index 0000000000000..6e9b28eb35597
--- /dev/null
+++ b/server/licenses/joda-time-2.12.2.jar.sha1
@@ -0,0 +1 @@
+78e18a7b4180e911dafba0a412adfa82c1e3d14b
\ No newline at end of file
diff --git a/server/licenses/jzlib-1.1.3.jar.sha1 b/server/licenses/jzlib-1.1.3.jar.sha1
new file mode 100644
index 0000000000000..2affa9b8cd51b
--- /dev/null
+++ b/server/licenses/jzlib-1.1.3.jar.sha1
@@ -0,0 +1 @@
+c01428efa717624f7aabf4df319939dda9646b2d
\ No newline at end of file
diff --git a/server/licenses/jzlib-LICENSE.txt b/server/licenses/jzlib-LICENSE.txt
new file mode 100644
index 0000000000000..245abb23411e0
--- /dev/null
+++ b/server/licenses/jzlib-LICENSE.txt
@@ -0,0 +1,29 @@
+JZlib 0.0.* were released under the GNU LGPL license.  Later, we have switched
+over to a BSD-style license.
+
+------------------------------------------------------------------------------
+Copyright (c) 2000-2011 ymnk, JCraft,Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+  Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+  The name of the authors may not be used to endorse or promote products
+  derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL JCRAFT, INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE
+BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/server/licenses/jzlib-NOTICE.txt b/server/licenses/jzlib-NOTICE.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/server/licenses/log4j-api-2.17.1.jar.sha1 b/server/licenses/log4j-api-2.17.1.jar.sha1
deleted file mode 100644
index 9d0e5dc631ed5..0000000000000
--- a/server/licenses/log4j-api-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d771af8e336e372fb5399c99edabe0919aeaf5b2
\ No newline at end of file
diff --git a/server/licenses/log4j-api-2.20.0.jar.sha1 b/server/licenses/log4j-api-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..37154d9861ac0
--- /dev/null
+++ b/server/licenses/log4j-api-2.20.0.jar.sha1
@@ -0,0 +1 @@
+1fe6082e660daf07c689a89c94dc0f49c26b44bb
\ No newline at end of file
diff --git a/server/licenses/log4j-core-2.17.1.jar.sha1 b/server/licenses/log4j-core-2.17.1.jar.sha1
deleted file mode 100644
index 7d4634f3d4e18..0000000000000
--- a/server/licenses/log4j-core-2.17.1.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-779f60f3844dadc3ef597976fcb1e5127b1f343d
\ No newline at end of file
diff --git a/server/licenses/log4j-core-2.20.0.jar.sha1 b/server/licenses/log4j-core-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..49c972626563b
--- /dev/null
+++ b/server/licenses/log4j-core-2.20.0.jar.sha1
@@ -0,0 +1 @@
+eb2a9a47b1396e00b5eee1264296729a70565cc0
\ No newline at end of file
diff --git a/server/licenses/log4j-jul-2.20.0.jar.sha1 b/server/licenses/log4j-jul-2.20.0.jar.sha1
new file mode 100644
index 0000000000000..a456651e4569e
--- /dev/null
+++ b/server/licenses/log4j-jul-2.20.0.jar.sha1
@@ -0,0 +1 @@
+8170e6118eac1ab332046c179718a0f107f688e1
\ No newline at end of file
diff --git a/server/licenses/log4j-jul-LICENSE.txt b/server/licenses/log4j-jul-LICENSE.txt
new file mode 100644
index 0000000000000..d645695673349
--- /dev/null
+++ b/server/licenses/log4j-jul-LICENSE.txt
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
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+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
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+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
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+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
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+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
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+      file or class name and description of purpose be included on the
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+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/server/licenses/log4j-jul-NOTICE.txt b/server/licenses/log4j-jul-NOTICE.txt
new file mode 100644
index 0000000000000..243a0391fb574
--- /dev/null
+++ b/server/licenses/log4j-jul-NOTICE.txt
@@ -0,0 +1,20 @@
+Apache Log4j
+Copyright 1999-2021 Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+
+ResolverUtil.java
+Copyright 2005-2006 Tim Fennell
+
+Dumbster SMTP test server
+Copyright 2004 Jason Paul Kitchen
+
+TypeUtil.java
+Copyright 2002-2012 Ramnivas Laddad, Juergen Hoeller, Chris Beams
+
+picocli (http://picocli.info)
+Copyright 2017 Remko Popma
+
+TimeoutBlockingWaitStrategy.java and parts of Util.java
+Copyright 2011 LMAX Ltd.
diff --git a/server/licenses/lucene-analysis-common-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-analysis-common-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 6ef0f1eafc345..0000000000000
--- a/server/licenses/lucene-analysis-common-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-bafd720282a371efe7b0e7238f9dee7e2ad3a586
\ No newline at end of file
diff --git a/server/licenses/lucene-analysis-common-9.7.0.jar.sha1 b/server/licenses/lucene-analysis-common-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..45d8f459573b1
--- /dev/null
+++ b/server/licenses/lucene-analysis-common-9.7.0.jar.sha1
@@ -0,0 +1 @@
+27ba6caaa4587a982cd451f7217b5a982bcfc44a
\ No newline at end of file
diff --git a/server/licenses/lucene-backward-codecs-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-backward-codecs-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 017333945a866..0000000000000
--- a/server/licenses/lucene-backward-codecs-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-597fe288a252a14c0876451c97afee2b4529f85a
\ No newline at end of file
diff --git a/server/licenses/lucene-backward-codecs-9.7.0.jar.sha1 b/server/licenses/lucene-backward-codecs-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..3981ea4fa226e
--- /dev/null
+++ b/server/licenses/lucene-backward-codecs-9.7.0.jar.sha1
@@ -0,0 +1 @@
+6389463bfbfcf902c8d31d12e9513a6818ac9d5e
\ No newline at end of file
diff --git a/server/licenses/lucene-core-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-core-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index a2ba0f0ffa43c..0000000000000
--- a/server/licenses/lucene-core-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-80cd2fff33ced89924771c7079d42bf82f1266f6
\ No newline at end of file
diff --git a/server/licenses/lucene-core-9.7.0.jar.sha1 b/server/licenses/lucene-core-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..2b0f77275c0ab
--- /dev/null
+++ b/server/licenses/lucene-core-9.7.0.jar.sha1
@@ -0,0 +1 @@
+ad391210ffd806931334be9670a35af00c56f959
\ No newline at end of file
diff --git a/server/licenses/lucene-grouping-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-grouping-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index ac0c1be0f952b..0000000000000
--- a/server/licenses/lucene-grouping-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-7059f47668a2942c60ad03b1d58eca8dcb010e4e
\ No newline at end of file
diff --git a/server/licenses/lucene-grouping-9.7.0.jar.sha1 b/server/licenses/lucene-grouping-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..90acbf6dcee8d
--- /dev/null
+++ b/server/licenses/lucene-grouping-9.7.0.jar.sha1
@@ -0,0 +1 @@
+8e6f0c229f4861be641047c33b05067176e4279c
\ No newline at end of file
diff --git a/server/licenses/lucene-highlighter-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-highlighter-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index fa08ed63f7c44..0000000000000
--- a/server/licenses/lucene-highlighter-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3c841ca23eb08a939fa49ba4af249c3b6d849c42
\ No newline at end of file
diff --git a/server/licenses/lucene-highlighter-9.7.0.jar.sha1 b/server/licenses/lucene-highlighter-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..bfcca0bc6cb5b
--- /dev/null
+++ b/server/licenses/lucene-highlighter-9.7.0.jar.sha1
@@ -0,0 +1 @@
+facb7c7ee0f75ed457a2d98f10d6430e25a53691
\ No newline at end of file
diff --git a/server/licenses/lucene-join-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-join-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 2a3e2a9107a60..0000000000000
--- a/server/licenses/lucene-join-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-4984e041ae68f5939c01e41b2c9648ae2c021340
\ No newline at end of file
diff --git a/server/licenses/lucene-join-9.7.0.jar.sha1 b/server/licenses/lucene-join-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..0dab3a7ddc41a
--- /dev/null
+++ b/server/licenses/lucene-join-9.7.0.jar.sha1
@@ -0,0 +1 @@
+d041bdc0947a14223cf68357407ee18b21027587
\ No newline at end of file
diff --git a/server/licenses/lucene-memory-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-memory-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index eefd08d222ef8..0000000000000
--- a/server/licenses/lucene-memory-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-fead9467ce65469579168eb0f47e014fdb3c63d9
\ No newline at end of file
diff --git a/server/licenses/lucene-memory-9.7.0.jar.sha1 b/server/licenses/lucene-memory-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..357a9c4b2ea26
--- /dev/null
+++ b/server/licenses/lucene-memory-9.7.0.jar.sha1
@@ -0,0 +1 @@
+0fade51ee353e15ddbbc45262aafe6f99ed020f1
\ No newline at end of file
diff --git a/server/licenses/lucene-misc-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-misc-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 226f97cf6f3bc..0000000000000
--- a/server/licenses/lucene-misc-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-d98ab1966b8ca53b70fe071281bcea27d602ec30
\ No newline at end of file
diff --git a/server/licenses/lucene-misc-9.7.0.jar.sha1 b/server/licenses/lucene-misc-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..da5e1921626b2
--- /dev/null
+++ b/server/licenses/lucene-misc-9.7.0.jar.sha1
@@ -0,0 +1 @@
+7fcf451e2376526c3a027958812866cc5b0ff13f
\ No newline at end of file
diff --git a/server/licenses/lucene-queries-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-queries-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index c151e6b76e21a..0000000000000
--- a/server/licenses/lucene-queries-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-895e27127ae55031e35e152da8be941bd55f7f6a
\ No newline at end of file
diff --git a/server/licenses/lucene-queries-9.7.0.jar.sha1 b/server/licenses/lucene-queries-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..fa82e95a7e19f
--- /dev/null
+++ b/server/licenses/lucene-queries-9.7.0.jar.sha1
@@ -0,0 +1 @@
+126989d4622419aa06fcbf3a342e859cab8c8799
\ No newline at end of file
diff --git a/server/licenses/lucene-queryparser-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-queryparser-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index b73b7152aed05..0000000000000
--- a/server/licenses/lucene-queryparser-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-1433392237ea01ef35f4e2ffc52f496b0669624c
\ No newline at end of file
diff --git a/server/licenses/lucene-queryparser-9.7.0.jar.sha1 b/server/licenses/lucene-queryparser-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..438db0aea66e1
--- /dev/null
+++ b/server/licenses/lucene-queryparser-9.7.0.jar.sha1
@@ -0,0 +1 @@
+6e77bde908ff698354e4a2149e6dd4658b56d7b0
\ No newline at end of file
diff --git a/server/licenses/lucene-sandbox-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-sandbox-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index d441dd2f8cb31..0000000000000
--- a/server/licenses/lucene-sandbox-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-b0688963ca8288f5a3e47ca6e4b38bc2fde780e7
\ No newline at end of file
diff --git a/server/licenses/lucene-sandbox-9.7.0.jar.sha1 b/server/licenses/lucene-sandbox-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..38b0b1cccbc29
--- /dev/null
+++ b/server/licenses/lucene-sandbox-9.7.0.jar.sha1
@@ -0,0 +1 @@
+9f3e8e1947f2f1c5784132444af51a060ff0b4bf
\ No newline at end of file
diff --git a/server/licenses/lucene-spatial-extras-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-spatial-extras-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 5ffa78a6e7d87..0000000000000
--- a/server/licenses/lucene-spatial-extras-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-206e8918a726710c8a6fb927e59adf26c6ad5bed
\ No newline at end of file
diff --git a/server/licenses/lucene-spatial-extras-9.7.0.jar.sha1 b/server/licenses/lucene-spatial-extras-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..48679df469fd1
--- /dev/null
+++ b/server/licenses/lucene-spatial-extras-9.7.0.jar.sha1
@@ -0,0 +1 @@
+01b0bc7a407d8c35a70a1adf7966bb3e7caae928
\ No newline at end of file
diff --git a/server/licenses/lucene-spatial3d-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-spatial3d-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 8c4bb08303c34..0000000000000
--- a/server/licenses/lucene-spatial3d-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-3d1e26c37b45bdf2ef598d16468220ab33983a8f
\ No newline at end of file
diff --git a/server/licenses/lucene-spatial3d-9.7.0.jar.sha1 b/server/licenses/lucene-spatial3d-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..55d4d217fa6b9
--- /dev/null
+++ b/server/licenses/lucene-spatial3d-9.7.0.jar.sha1
@@ -0,0 +1 @@
+7c6b1b6e0a70c9cd177371e648648c2f896742a2
\ No newline at end of file
diff --git a/server/licenses/lucene-suggest-9.1.0-snapshot-ea989fe8f30.jar.sha1 b/server/licenses/lucene-suggest-9.1.0-snapshot-ea989fe8f30.jar.sha1
deleted file mode 100644
index 3c8d9b87da0e5..0000000000000
--- a/server/licenses/lucene-suggest-9.1.0-snapshot-ea989fe8f30.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-69ab05339614766c732fef7c037cc5b676bd40dc
\ No newline at end of file
diff --git a/server/licenses/lucene-suggest-9.7.0.jar.sha1 b/server/licenses/lucene-suggest-9.7.0.jar.sha1
new file mode 100644
index 0000000000000..d4d7e6cd6bed9
--- /dev/null
+++ b/server/licenses/lucene-suggest-9.7.0.jar.sha1
@@ -0,0 +1 @@
+5c37fd9a5d71dc87fe1cd4c18ff295ec8cfac170
\ No newline at end of file
diff --git a/server/licenses/protobuf-java-3.22.3.jar.sha1 b/server/licenses/protobuf-java-3.22.3.jar.sha1
new file mode 100644
index 0000000000000..80feeec023e7b
--- /dev/null
+++ b/server/licenses/protobuf-java-3.22.3.jar.sha1
@@ -0,0 +1 @@
+fdee98b8f6abab73f146a4edb4c09e56f8278d03
\ No newline at end of file
diff --git a/plugins/repository-gcs/licenses/protobuf-LICENSE.txt b/server/licenses/protobuf-java-LICENSE.txt
similarity index 100%
rename from plugins/repository-gcs/licenses/protobuf-LICENSE.txt
rename to server/licenses/protobuf-java-LICENSE.txt
diff --git a/plugins/repository-gcs/licenses/protobuf-NOTICE.txt b/server/licenses/protobuf-java-NOTICE.txt
similarity index 100%
rename from plugins/repository-gcs/licenses/protobuf-NOTICE.txt
rename to server/licenses/protobuf-java-NOTICE.txt
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/IndicesRequestIT.java b/server/src/internalClusterTest/java/org/opensearch/action/IndicesRequestIT.java
index 17366cf0d08fc..6e4d66b74d7c1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/IndicesRequestIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/IndicesRequestIT.java
@@ -56,6 +56,8 @@
 import org.opensearch.action.admin.indices.recovery.RecoveryRequest;
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.admin.indices.refresh.TransportShardRefreshAction;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsAction;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequest;
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsAction;
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequest;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsAction;
@@ -92,9 +94,9 @@
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
@@ -110,7 +112,6 @@
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-
 import org.junit.After;
 import org.junit.Before;
 
@@ -468,6 +469,17 @@ public void testRecovery() {
         assertSameIndices(recoveryRequest, recoveryAction);
     }
 
+    public void testSegmentReplicationStats() {
+        String segmentReplicationAction = SegmentReplicationStatsAction.NAME + "[n]";
+        interceptTransportActions(segmentReplicationAction);
+
+        SegmentReplicationStatsRequest segmentReplicationStatsRequest = new SegmentReplicationStatsRequest(randomIndicesOrAliases());
+        internalCluster().coordOnlyNodeClient().admin().indices().segmentReplicationStats(segmentReplicationStatsRequest).actionGet();
+
+        clearInterceptedActions();
+        assertSameIndices(segmentReplicationStatsRequest, segmentReplicationAction);
+    }
+
     public void testSegments() {
         String segmentsAction = IndicesSegmentsAction.NAME + "[n]";
         interceptTransportActions(segmentsAction);
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/ListenerActionIT.java b/server/src/internalClusterTest/java/org/opensearch/action/ListenerActionIT.java
index 1512fa4934ca1..c82ca0a06f4a1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/ListenerActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/ListenerActionIT.java
@@ -36,6 +36,7 @@
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.client.Client;
 import org.opensearch.client.Requests;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.concurrent.CountDownLatch;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/RejectionActionIT.java b/server/src/internalClusterTest/java/org/opensearch/action/RejectionActionIT.java
index f930b9e9cfda0..e52df4476241b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/RejectionActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/RejectionActionIT.java
@@ -38,7 +38,8 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/ClientTimeoutIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/ClientTimeoutIT.java
index d83e8112569ee..340caa75c61d9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/ClientTimeoutIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/ClientTimeoutIT.java
@@ -8,9 +8,9 @@
 
 package org.opensearch.action.admin;
 
-import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
-import org.opensearch.action.admin.cluster.node.info.NodesInfoAction;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
+import org.opensearch.action.admin.cluster.node.info.NodesInfoAction;
+import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsAction;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -33,10 +33,10 @@
 import java.util.Collections;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.lessThan;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class ClientTimeoutIT extends OpenSearchIntegTestCase {
@@ -47,7 +47,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     public void testNodesInfoTimeout() {
-        String masterNode = internalCluster().startMasterOnlyNode();
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         String anotherDataNode = internalCluster().startDataOnlyNode();
 
@@ -65,11 +65,11 @@ public void testNodesInfoTimeout() {
             nodes.add(node.getNode().getName());
         }
         assertThat(response.getNodes().size(), equalTo(2));
-        assertThat(nodes.contains(masterNode), is(true));
+        assertThat(nodes.contains(clusterManagerNode), is(true));
     }
 
     public void testNodesStatsTimeout() {
-        String masterNode = internalCluster().startMasterOnlyNode();
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         String anotherDataNode = internalCluster().startDataOnlyNode();
         TimeValue timeout = TimeValue.timeValueMillis(1000);
@@ -87,11 +87,11 @@ public void testNodesStatsTimeout() {
             nodes.add(node.getNode().getName());
         }
         assertThat(response.getNodes().size(), equalTo(2));
-        assertThat(nodes.contains(masterNode), is(true));
+        assertThat(nodes.contains(clusterManagerNode), is(true));
     }
 
     public void testListTasksTimeout() {
-        String masterNode = internalCluster().startMasterOnlyNode();
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         String anotherDataNode = internalCluster().startDataOnlyNode();
         TimeValue timeout = TimeValue.timeValueMillis(1000);
@@ -108,7 +108,7 @@ public void testListTasksTimeout() {
     }
 
     public void testRecoveriesWithTimeout() {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         String anotherDataNode = internalCluster().startDataOnlyNode();
 
@@ -148,7 +148,7 @@ public void testRecoveriesWithTimeout() {
     }
 
     public void testStatsWithTimeout() {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         String anotherDataNode = internalCluster().startDataOnlyNode();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/HotThreadsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/HotThreadsIT.java
index ab44c95b4f5a6..6343bd127c458 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/HotThreadsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/HotThreadsIT.java
@@ -32,11 +32,11 @@
 package org.opensearch.action.admin;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodeHotThreads;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsRequestBuilder;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsResponse;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/ReloadSecureSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/ReloadSecureSettingsIT.java
index 7e6dad47121a9..8deb7557966a8 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/ReloadSecureSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/ReloadSecureSettingsIT.java
@@ -33,13 +33,13 @@
 package org.opensearch.action.admin;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.reload.NodesReloadSecureSettingsResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.KeyStoreWrapper;
 import org.opensearch.common.settings.SecureSettings;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.PluginsService;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainIT.java
index 8c7e5378516bf..a9a6993ff8d64 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainIT.java
@@ -49,18 +49,17 @@
 import org.opensearch.cluster.routing.allocation.NodeAllocationResult;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -1110,7 +1109,7 @@ public void testAssignedReplicaOnSpecificNode() throws Exception {
 
     public void testCannotAllocateStaleReplicaExplanation() throws Exception {
         logger.info("--> starting 3 nodes");
-        final String masterNode = internalCluster().startNode();
+        final String clusterManagerNode = internalCluster().startNode();
         // start replica node first, so it's path will be used first when we start a node after
         // stopping all of them at end of test.
         final String replicaNode = internalCluster().startNode();
@@ -1123,7 +1122,7 @@ public void testCannotAllocateStaleReplicaExplanation() throws Exception {
             1,
             Settings.builder()
                 .put("index.routing.allocation.include._name", primaryNode)
-                .put("index.routing.allocation.exclude._name", masterNode)
+                .put("index.routing.allocation.exclude._name", clusterManagerNode)
                 .build(),
             ActiveShardCount.ONE
         );
@@ -1165,7 +1164,7 @@ public void testCannotAllocateStaleReplicaExplanation() throws Exception {
 
         logger.info("--> restart the node with the stale replica");
         String restartedNode = internalCluster().startDataOnlyNode(replicaDataPathSettings);
-        ensureClusterSizeConsistency(); // wait for the master to finish processing join.
+        ensureClusterSizeConsistency(); // wait for the cluster-manager to finish processing join.
 
         // wait until the system has fetched shard data and we know there is no valid shard copy
         assertBusy(() -> {
@@ -1275,7 +1274,7 @@ private ClusterAllocationExplanation runExplain(boolean primary, String nodeId,
             XContentBuilder builder = JsonXContent.contentBuilder();
             builder.prettyPrint();
             builder.humanReadable(true);
-            logger.debug("--> explain json output: \n{}", Strings.toString(explanation.toXContent(builder, ToXContent.EMPTY_PARAMS)));
+            logger.debug("--> explain json output: \n{}", explanation.toXContent(builder, ToXContent.EMPTY_PARAMS).toString());
         }
         return explanation;
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/AbstractTasksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/AbstractTasksIT.java
new file mode 100644
index 0000000000000..0197ccf059737
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/AbstractTasksIT.java
@@ -0,0 +1,190 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.node.tasks;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.ResourceNotFoundException;
+import org.opensearch.action.admin.cluster.node.tasks.get.GetTaskResponse;
+import org.opensearch.action.support.WriteRequest;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.tasks.TaskInfo;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.tasks.MockTaskManager;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * Base IT test class for Tasks ITs
+ */
+abstract class AbstractTasksIT extends OpenSearchIntegTestCase {
+
+    protected Map<Tuple<String, String>, RecordingTaskManagerListener> listeners = new HashMap<>();
+
+    @Override
+    protected Collection<Class<? extends Plugin>> getMockPlugins() {
+        Collection<Class<? extends Plugin>> mockPlugins = new ArrayList<>(super.getMockPlugins());
+        mockPlugins.remove(MockTransportService.TestPlugin.class);
+        return mockPlugins;
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class, TestTaskPlugin.class);
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(MockTaskManager.USE_MOCK_TASK_MANAGER_SETTING.getKey(), true)
+            .build();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
+            ((MockTaskManager) internalCluster().getInstance(TransportService.class, entry.getKey().v1()).getTaskManager()).removeListener(
+                entry.getValue()
+            );
+        }
+        listeners.clear();
+        super.tearDown();
+    }
+
+    /**
+     * Registers recording task event listeners with the given action mask on all nodes
+     */
+    protected void registerTaskManagerListeners(String actionMasks) {
+        for (String nodeName : internalCluster().getNodeNames()) {
+            DiscoveryNode node = internalCluster().getInstance(ClusterService.class, nodeName).localNode();
+            RecordingTaskManagerListener listener = new RecordingTaskManagerListener(node.getId(), actionMasks.split(","));
+            ((MockTaskManager) internalCluster().getInstance(TransportService.class, nodeName).getTaskManager()).addListener(listener);
+            RecordingTaskManagerListener oldListener = listeners.put(new Tuple<>(node.getName(), actionMasks), listener);
+            assertNull(oldListener);
+        }
+    }
+
+    /**
+     * Resets all recording task event listeners with the given action mask on all nodes
+     */
+    protected void resetTaskManagerListeners(String actionMasks) {
+        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
+            if (actionMasks == null || entry.getKey().v2().equals(actionMasks)) {
+                entry.getValue().reset();
+            }
+        }
+    }
+
+    /**
+     * Returns the number of events that satisfy the criteria across all nodes
+     *
+     * @param actionMasks action masks to match
+     * @return number of events that satisfy the criteria
+     */
+    protected int numberOfEvents(String actionMasks, Function<Tuple<Boolean, TaskInfo>, Boolean> criteria) {
+        return findEvents(actionMasks, criteria).size();
+    }
+
+    /**
+     * Returns all events that satisfy the criteria across all nodes
+     *
+     * @param actionMasks action masks to match
+     * @return number of events that satisfy the criteria
+     */
+    protected List<TaskInfo> findEvents(String actionMasks, Function<Tuple<Boolean, TaskInfo>, Boolean> criteria) {
+        List<TaskInfo> events = new ArrayList<>();
+        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
+            if (actionMasks == null || entry.getKey().v2().equals(actionMasks)) {
+                for (Tuple<Boolean, TaskInfo> taskEvent : entry.getValue().getEvents()) {
+                    if (criteria.apply(taskEvent)) {
+                        events.add(taskEvent.v2());
+                    }
+                }
+            }
+        }
+        return events;
+    }
+
+    protected Map<Long, List<ThreadResourceInfo>> getThreadStats(String actionMasks, TaskId taskId) {
+        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
+            if (actionMasks == null || entry.getKey().v2().equals(actionMasks)) {
+                for (Tuple<TaskId, Map<Long, List<ThreadResourceInfo>>> threadStats : entry.getValue().getThreadStats()) {
+                    if (taskId.equals(threadStats.v1())) {
+                        return threadStats.v2();
+                    }
+                }
+            }
+        }
+        return new HashMap<>();
+    }
+
+    /**
+     * Asserts that all tasks in the tasks list have the same parentTask
+     */
+    protected void assertParentTask(List<TaskInfo> tasks, TaskInfo parentTask) {
+        for (TaskInfo task : tasks) {
+            assertParentTask(task, parentTask);
+        }
+    }
+
+    protected void assertParentTask(TaskInfo task, TaskInfo parentTask) {
+        assertTrue(task.getParentTaskId().isSet());
+        assertEquals(parentTask.getTaskId().getNodeId(), task.getParentTaskId().getNodeId());
+        assertTrue(Strings.hasLength(task.getParentTaskId().getNodeId()));
+        assertEquals(parentTask.getId(), task.getParentTaskId().getId());
+    }
+
+    protected void expectNotFound(ThrowingRunnable r) {
+        Exception e = expectThrows(Exception.class, r);
+        ResourceNotFoundException notFound = (ResourceNotFoundException) ExceptionsHelper.unwrap(e, ResourceNotFoundException.class);
+        if (notFound == null) {
+            throw new AssertionError("Expected " + ResourceNotFoundException.class.getSimpleName(), e);
+        }
+    }
+
+    /**
+     * Fetch the task status from the list tasks API using it's "fallback to get from the task index" behavior. Asserts some obvious stuff
+     * about the fetched task and returns a map of it's status.
+     */
+    protected GetTaskResponse expectFinishedTask(TaskId taskId) throws IOException {
+        GetTaskResponse response = client().admin().cluster().prepareGetTask(taskId).get();
+        assertTrue("the task should have been completed before fetching", response.getTask().isCompleted());
+        TaskInfo info = response.getTask().getTask();
+        assertEquals(taskId, info.getTaskId());
+        assertNull(info.getStatus()); // The test task doesn't have any status
+        return response;
+    }
+
+    protected void indexDocumentsWithRefresh(String indexName, int numDocs) {
+        for (int i = 0; i < numDocs; i++) {
+            client().prepareIndex(indexName)
+                .setId("test_id_" + String.valueOf(i))
+                .setSource("{\"foo_" + String.valueOf(i) + "\": \"bar_" + String.valueOf(i) + "\"}", MediaTypeRegistry.JSON)
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .get();
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
index 6c507171091e7..c4dcedcc722cf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
@@ -31,14 +31,12 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.apache.lucene.util.SetOnce;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.LatchedActionListener;
@@ -50,31 +48,37 @@
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskCancelledException;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.tasks.TaskManager;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
-
 import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -87,6 +91,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
@@ -94,7 +99,7 @@
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class CancellableTasksIT extends OpenSearchIntegTestCase {
+public class CancellableTasksIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int idGenerator = 0;
     static final Map<TestRequest, CountDownLatch> beforeSendLatches = ConcurrentCollections.newConcurrentMap();
@@ -102,6 +107,23 @@ public class CancellableTasksIT extends OpenSearchIntegTestCase {
     static final Map<TestRequest, CountDownLatch> beforeExecuteLatches = ConcurrentCollections.newConcurrentMap();
     static final Map<TestRequest, CountDownLatch> completedLatches = ConcurrentCollections.newConcurrentMap();
 
+    public CancellableTasksIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Before
     public void resetTestStates() {
         idGenerator = 0;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/ConcurrentSearchTasksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/ConcurrentSearchTasksIT.java
new file mode 100644
index 0000000000000..ceacb028698de
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/ConcurrentSearchTasksIT.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.node.tasks;
+
+import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequest;
+import org.opensearch.action.search.SearchAction;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.FeatureFlagSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.tasks.TaskInfo;
+import org.hamcrest.MatcherAssert;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.notNullValue;
+
+/**
+ * Integration tests for task management API with Concurrent Segment Search
+ *
+ * The way the test framework bootstraps the test cluster makes it difficult to parameterize the feature flag.
+ * Once concurrent search is moved behind a cluster setting we can parameterize these tests behind the setting.
+ */
+public class ConcurrentSearchTasksIT extends AbstractTasksIT {
+
+    private static final int INDEX_SEARCHER_THREADS = 10;
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put("thread_pool.index_searcher.size", INDEX_SEARCHER_THREADS)
+            .put("thread_pool.index_searcher.queue_size", INDEX_SEARCHER_THREADS)
+            .build();
+    }
+
+    private int getSegmentCount(String indexName) {
+        return client().admin()
+            .indices()
+            .segments(new IndicesSegmentsRequest(indexName))
+            .actionGet()
+            .getIndices()
+            .get(indexName)
+            .getShards()
+            .get(0)
+            .getShards()[0].getSegments()
+            .size();
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        Settings.Builder featureSettings = Settings.builder();
+        for (Setting builtInFlag : FeatureFlagSettings.BUILT_IN_FEATURE_FLAGS) {
+            featureSettings.put(builtInFlag.getKey(), builtInFlag.getDefaultRaw(Settings.EMPTY));
+        }
+        featureSettings.put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, true);
+        return featureSettings.build();
+    }
+
+    /**
+     * Tests the number of threads that worked on a search task.
+     *
+     * Currently, we try to control concurrency by creating an index with 7 segments and rely on
+     * the way concurrent search creates leaf slices from segments. Once more concurrency controls are introduced
+     * we should improve this test to use those methods.
+     */
+    public void testConcurrentSearchTaskTracking() {
+        final String INDEX_NAME = "test";
+        final int NUM_SHARDS = 1;
+        final int NUM_DOCS = 7;
+
+        registerTaskManagerListeners(SearchAction.NAME);  // coordinator task
+        registerTaskManagerListeners(SearchAction.NAME + "[*]");  // shard task
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+        ensureGreen(INDEX_NAME); // Make sure all shards are allocated to catch replication tasks
+        indexDocumentsWithRefresh(INDEX_NAME, NUM_DOCS); // Concurrent search requires >5 segments or >250,000 docs to have concurrency, so
+                                                         // we index 7 docs flushing between each to create new segments
+        assertSearchResponse(client().prepareSearch(INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get());
+
+        // the search operation should produce one coordinator task
+        List<TaskInfo> mainTask = findEvents(SearchAction.NAME, Tuple::v1);
+        assertEquals(1, mainTask.size());
+        TaskInfo mainTaskInfo = mainTask.get(0);
+
+        List<TaskInfo> shardTasks = findEvents(SearchAction.NAME + "[*]", Tuple::v1);
+        assertEquals(NUM_SHARDS, shardTasks.size()); // We should only have 1 shard search task per shard
+        for (TaskInfo taskInfo : shardTasks) {
+            MatcherAssert.assertThat(taskInfo.getParentTaskId(), notNullValue());
+            assertEquals(mainTaskInfo.getTaskId(), taskInfo.getParentTaskId());
+
+            Map<Long, List<ThreadResourceInfo>> threadStats = getThreadStats(SearchAction.NAME + "[*]", taskInfo.getTaskId());
+            // Concurrent search forks each slice of 5 segments to different thread
+            assertEquals((int) Math.ceil(getSegmentCount(INDEX_NAME) / 5.0), threadStats.size());
+
+            // assert that all task descriptions have non-zero length
+            MatcherAssert.assertThat(taskInfo.getDescription().length(), greaterThan(0));
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TaskStorageRetryIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TaskStorageRetryIT.java
index e710d3a8438d8..455be343de2c5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TaskStorageRetryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TaskStorageRetryIT.java
@@ -36,9 +36,9 @@
 import org.opensearch.action.support.PlainListenableActionFuture;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.threadpool.ThreadPool;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TasksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TasksIT.java
index fbac2f7dbff6e..c7d75108883dd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TasksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/TasksIT.java
@@ -32,12 +32,9 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.health.ClusterHealthAction;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
@@ -57,32 +54,25 @@
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.action.support.replication.TransportReplicationActionTests;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.tasks.TaskResult;
 import org.opensearch.tasks.TaskResultsService;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.tasks.MockTaskManager;
 import org.opensearch.test.tasks.MockTaskManagerListener;
-import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.ReceiveTimeoutTransportException;
 import org.opensearch.transport.TransportService;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -117,32 +107,10 @@
 /**
  * Integration tests for task management API
  * <p>
- * We need at least 2 nodes so we have a master node a non-master node
+ * We need at least 2 nodes so we have a cluster-manager node a non-cluster-manager node
  */
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, minNumDataNodes = 2)
-public class TasksIT extends OpenSearchIntegTestCase {
-
-    private Map<Tuple<String, String>, RecordingTaskManagerListener> listeners = new HashMap<>();
-
-    @Override
-    protected Collection<Class<? extends Plugin>> getMockPlugins() {
-        Collection<Class<? extends Plugin>> mockPlugins = new ArrayList<>(super.getMockPlugins());
-        mockPlugins.remove(MockTransportService.TestPlugin.class);
-        return mockPlugins;
-    }
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Arrays.asList(MockTransportService.TestPlugin.class, TestTaskPlugin.class);
-    }
-
-    @Override
-    protected Settings nodeSettings(int nodeOrdinal) {
-        return Settings.builder()
-            .put(super.nodeSettings(nodeOrdinal))
-            .put(MockTaskManager.USE_MOCK_TASK_MANAGER_SETTING.getKey(), true)
-            .build();
-    }
+public class TasksIT extends AbstractTasksIT {
 
     public void testTaskCounts() {
         // Run only on data nodes
@@ -154,18 +122,18 @@ public void testTaskCounts() {
         assertThat(response.getTasks().size(), greaterThanOrEqualTo(cluster().numDataNodes()));
     }
 
-    public void testMasterNodeOperationTasks() {
+    public void testClusterManagerNodeOperationTasks() {
         registerTaskManagerListeners(ClusterHealthAction.NAME);
 
-        // First run the health on the master node - should produce only one task on the master node
-        internalCluster().masterClient().admin().cluster().prepareHealth().get();
+        // First run the health on the cluster-manager node - should produce only one task on the cluster-manager node
+        internalCluster().clusterManagerClient().admin().cluster().prepareHealth().get();
         assertEquals(1, numberOfEvents(ClusterHealthAction.NAME, Tuple::v1)); // counting only registration events
         assertEquals(1, numberOfEvents(ClusterHealthAction.NAME, event -> event.v1() == false)); // counting only unregistration events
 
         resetTaskManagerListeners(ClusterHealthAction.NAME);
 
-        // Now run the health on a non-master node - should produce one task on master and one task on another node
-        internalCluster().nonMasterClient().admin().cluster().prepareHealth().get();
+        // Now run the health on a non-cluster-manager node - should produce one task on cluster-manager and one task on another node
+        internalCluster().nonClusterManagerClient().admin().cluster().prepareHealth().get();
         assertEquals(2, numberOfEvents(ClusterHealthAction.NAME, Tuple::v1)); // counting only registration events
         assertEquals(2, numberOfEvents(ClusterHealthAction.NAME, event -> event.v1() == false)); // counting only unregistration events
         List<TaskInfo> tasks = findEvents(ClusterHealthAction.NAME, Tuple::v1);
@@ -319,7 +287,9 @@ public void testTransportBulkTasks() {
         ensureGreen("test"); // Make sure all shards are allocated to catch replication tasks
         // ensures the mapping is available on all nodes so we won't retry the request (in case replicas don't have the right mapping).
         client().admin().indices().preparePutMapping("test").setSource("foo", "type=keyword").get();
-        client().prepareBulk().add(client().prepareIndex("test").setId("test_id").setSource("{\"foo\": \"bar\"}", XContentType.JSON)).get();
+        client().prepareBulk()
+            .add(client().prepareIndex("test").setId("test_id").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON))
+            .get();
 
         // the bulk operation should produce one main task
         List<TaskInfo> topTask = findEvents(BulkAction.NAME, Tuple::v1);
@@ -370,7 +340,7 @@ public void testSearchTaskDescriptions() {
         ensureGreen("test"); // Make sure all shards are allocated to catch replication tasks
         client().prepareIndex("test")
             .setId("test_id")
-            .setSource("{\"foo\": \"bar\"}", XContentType.JSON)
+            .setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON)
             .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
             .get();
 
@@ -470,6 +440,9 @@ public void onTaskUnregistered(Task task) {}
 
                     @Override
                     public void waitForTaskCompletion(Task task) {}
+
+                    @Override
+                    public void taskExecutionStarted(Task task, Boolean closeableInvoked) {}
                 });
             }
             // Need to run the task in a separate thread because node client's .execute() is blocked by our task listener
@@ -507,14 +480,12 @@ public void waitForTaskCompletion(Task task) {}
             if (index != null) {
                 index.join();
             }
-            assertBusy(
-                () -> {
-                    assertEquals(
-                        emptyList(),
-                        client().admin().cluster().prepareListTasks().setActions("indices:data/write/index*").get().getTasks()
-                    );
-                }
-            );
+            assertBusy(() -> {
+                assertEquals(
+                    emptyList(),
+                    client().admin().cluster().prepareListTasks().setActions("indices:data/write/index*").get().getTasks()
+                );
+            });
         }
     }
 
@@ -542,6 +513,17 @@ public void testTasksCancellation() throws Exception {
             .get();
         assertEquals(1, cancelTasksResponse.getTasks().size());
 
+        // Tasks are marked as cancelled at this point but not yet completed.
+        List<TaskInfo> taskInfoList = client().admin()
+            .cluster()
+            .prepareListTasks()
+            .setActions(TestTaskPlugin.TestTaskAction.NAME + "*")
+            .get()
+            .getTasks();
+        for (TaskInfo taskInfo : taskInfoList) {
+            assertTrue(taskInfo.isCancelled());
+            assertNotNull(taskInfo.getCancellationStartTime());
+        }
         future.get();
 
         logger.info("--> checking that test tasks are not running");
@@ -651,6 +633,9 @@ public void waitForTaskCompletion(Task task) {
                         waitForWaitingToStart.countDown();
                     }
 
+                    @Override
+                    public void taskExecutionStarted(Task task, Boolean closeableInvoked) {}
+
                     @Override
                     public void onTaskRegistered(Task task) {}
 
@@ -907,7 +892,8 @@ public void testNodeNotFoundButTaskFound() throws Exception {
                     false,
                     false,
                     TaskId.EMPTY_TASK_ID,
-                    Collections.emptyMap()
+                    Collections.emptyMap(),
+                    null
                 ),
                 new RuntimeException("test")
             ),
@@ -935,106 +921,4 @@ public void onFailure(Exception e) {
         assertNotNull(response.getTask().getError());
         assertNull(response.getTask().getResponse());
     }
-
-    @Override
-    public void tearDown() throws Exception {
-        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
-            ((MockTaskManager) internalCluster().getInstance(TransportService.class, entry.getKey().v1()).getTaskManager()).removeListener(
-                entry.getValue()
-            );
-        }
-        listeners.clear();
-        super.tearDown();
-    }
-
-    /**
-     * Registers recording task event listeners with the given action mask on all nodes
-     */
-    private void registerTaskManagerListeners(String actionMasks) {
-        for (String nodeName : internalCluster().getNodeNames()) {
-            DiscoveryNode node = internalCluster().getInstance(ClusterService.class, nodeName).localNode();
-            RecordingTaskManagerListener listener = new RecordingTaskManagerListener(node.getId(), actionMasks.split(","));
-            ((MockTaskManager) internalCluster().getInstance(TransportService.class, nodeName).getTaskManager()).addListener(listener);
-            RecordingTaskManagerListener oldListener = listeners.put(new Tuple<>(node.getName(), actionMasks), listener);
-            assertNull(oldListener);
-        }
-    }
-
-    /**
-     * Resets all recording task event listeners with the given action mask on all nodes
-     */
-    private void resetTaskManagerListeners(String actionMasks) {
-        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
-            if (actionMasks == null || entry.getKey().v2().equals(actionMasks)) {
-                entry.getValue().reset();
-            }
-        }
-    }
-
-    /**
-     * Returns the number of events that satisfy the criteria across all nodes
-     *
-     * @param actionMasks action masks to match
-     * @return number of events that satisfy the criteria
-     */
-    private int numberOfEvents(String actionMasks, Function<Tuple<Boolean, TaskInfo>, Boolean> criteria) {
-        return findEvents(actionMasks, criteria).size();
-    }
-
-    /**
-     * Returns all events that satisfy the criteria across all nodes
-     *
-     * @param actionMasks action masks to match
-     * @return number of events that satisfy the criteria
-     */
-    private List<TaskInfo> findEvents(String actionMasks, Function<Tuple<Boolean, TaskInfo>, Boolean> criteria) {
-        List<TaskInfo> events = new ArrayList<>();
-        for (Map.Entry<Tuple<String, String>, RecordingTaskManagerListener> entry : listeners.entrySet()) {
-            if (actionMasks == null || entry.getKey().v2().equals(actionMasks)) {
-                for (Tuple<Boolean, TaskInfo> taskEvent : entry.getValue().getEvents()) {
-                    if (criteria.apply(taskEvent)) {
-                        events.add(taskEvent.v2());
-                    }
-                }
-            }
-        }
-        return events;
-    }
-
-    /**
-     * Asserts that all tasks in the tasks list have the same parentTask
-     */
-    private void assertParentTask(List<TaskInfo> tasks, TaskInfo parentTask) {
-        for (TaskInfo task : tasks) {
-            assertParentTask(task, parentTask);
-        }
-    }
-
-    private void assertParentTask(TaskInfo task, TaskInfo parentTask) {
-        assertTrue(task.getParentTaskId().isSet());
-        assertEquals(parentTask.getTaskId().getNodeId(), task.getParentTaskId().getNodeId());
-        assertTrue(Strings.hasLength(task.getParentTaskId().getNodeId()));
-        assertEquals(parentTask.getId(), task.getParentTaskId().getId());
-    }
-
-    private void expectNotFound(ThrowingRunnable r) {
-        Exception e = expectThrows(Exception.class, r);
-        ResourceNotFoundException notFound = (ResourceNotFoundException) ExceptionsHelper.unwrap(e, ResourceNotFoundException.class);
-        if (notFound == null) {
-            throw new AssertionError("Expected " + ResourceNotFoundException.class.getSimpleName(), e);
-        }
-    }
-
-    /**
-     * Fetch the task status from the list tasks API using it's "fallback to get from the task index" behavior. Asserts some obvious stuff
-     * about the fetched task and returns a map of it's status.
-     */
-    private GetTaskResponse expectFinishedTask(TaskId taskId) throws IOException {
-        GetTaskResponse response = client().admin().cluster().prepareGetTask(taskId).get();
-        assertTrue("the task should have been completed before fetching", response.getTask().isCompleted());
-        TaskInfo info = response.getTask().getTask();
-        assertEquals(taskId, info.getTaskId());
-        assertNull(info.getStatus()); // The test task doesn't have any status
-        return response;
-    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/repositories/RepositoryBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/repositories/RepositoryBlocksIT.java
index 4d3b60da0987f..aff7c5d9876ac 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/repositories/RepositoryBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/repositories/RepositoryBlocksIT.java
@@ -97,7 +97,7 @@ public void testVerifyRepositoryWithBlocks() {
                 .prepareVerifyRepository("test-repo-blocks")
                 .execute()
                 .actionGet();
-            assertThat(response.getNodes().size(), equalTo(cluster().numDataAndMasterNodes()));
+            assertThat(response.getNodes().size(), equalTo(cluster().numDataAndClusterManagerNodes()));
         } finally {
             setClusterReadOnly(false);
         }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/snapshots/SnapshotBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/snapshots/SnapshotBlocksIT.java
index 1731c607a066d..347011721c728 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/snapshots/SnapshotBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/snapshots/SnapshotBlocksIT.java
@@ -37,13 +37,11 @@
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusResponse;
-
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-
 import org.junit.Before;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_READ;
@@ -92,7 +90,7 @@ protected void setUpRepository() throws Exception {
 
         logger.info("--> verify the repository");
         VerifyRepositoryResponse verifyResponse = client().admin().cluster().prepareVerifyRepository(REPOSITORY_NAME).get();
-        assertThat(verifyResponse.getNodes().size(), equalTo(cluster().numDataAndMasterNodes()));
+        assertThat(verifyResponse.getNodes().size(), equalTo(cluster().numDataAndClusterManagerNodes()));
 
         logger.info("--> create a snapshot");
         CreateSnapshotResponse snapshotResponse = client().admin()
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/state/TransportClusterStateActionDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/state/TransportClusterStateActionDisruptionIT.java
index c6f47a01ed2d2..1a0cad36c8f04 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/state/TransportClusterStateActionDisruptionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/state/TransportClusterStateActionDisruptionIT.java
@@ -40,7 +40,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.discovery.MasterNotDiscoveredException;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
@@ -68,26 +68,29 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singletonList(MockTransportService.TestPlugin.class);
     }
 
-    public void testNonLocalRequestAlwaysFindsMaster() throws Exception {
-        runRepeatedlyWhileChangingMaster(() -> {
+    public void testNonLocalRequestAlwaysFindsClusterManager() throws Exception {
+        runRepeatedlyWhileChangingClusterManager(() -> {
             final ClusterStateRequestBuilder clusterStateRequestBuilder = client().admin()
                 .cluster()
                 .prepareState()
                 .clear()
                 .setNodes(true)
-                .setMasterNodeTimeout("100ms");
+                .setClusterManagerNodeTimeout("100ms");
             final ClusterStateResponse clusterStateResponse;
             try {
                 clusterStateResponse = clusterStateRequestBuilder.get();
-            } catch (MasterNotDiscoveredException e) {
+            } catch (ClusterManagerNotDiscoveredException e) {
                 return; // ok, we hit the disconnected node
             }
-            assertNotNull("should always contain a master node", clusterStateResponse.getState().nodes().getMasterNodeId());
+            assertNotNull(
+                "should always contain a cluster-manager node",
+                clusterStateResponse.getState().nodes().getClusterManagerNodeId()
+            );
         });
     }
 
     public void testLocalRequestAlwaysSucceeds() throws Exception {
-        runRepeatedlyWhileChangingMaster(() -> {
+        runRepeatedlyWhileChangingClusterManager(() -> {
             final String node = randomFrom(internalCluster().getNodeNames());
             final DiscoveryNodes discoveryNodes = client(node).admin()
                 .cluster()
@@ -95,7 +98,7 @@ public void testLocalRequestAlwaysSucceeds() throws Exception {
                 .clear()
                 .setLocal(true)
                 .setNodes(true)
-                .setMasterNodeTimeout("100ms")
+                .setClusterManagerNodeTimeout("100ms")
                 .get()
                 .getState()
                 .nodes();
@@ -108,8 +111,8 @@ public void testLocalRequestAlwaysSucceeds() throws Exception {
         });
     }
 
-    public void testNonLocalRequestAlwaysFindsMasterAndWaitsForMetadata() throws Exception {
-        runRepeatedlyWhileChangingMaster(() -> {
+    public void testNonLocalRequestAlwaysFindsClusterManagerAndWaitsForMetadata() throws Exception {
+        runRepeatedlyWhileChangingClusterManager(() -> {
             final String node = randomFrom(internalCluster().getNodeNames());
             final long metadataVersion = internalCluster().getInstance(ClusterService.class, node)
                 .getClusterApplierService()
@@ -123,25 +126,25 @@ public void testNonLocalRequestAlwaysFindsMasterAndWaitsForMetadata() throws Exc
                 .clear()
                 .setNodes(true)
                 .setMetadata(true)
-                .setMasterNodeTimeout(TimeValue.timeValueMillis(100))
+                .setClusterManagerNodeTimeout(TimeValue.timeValueMillis(100))
                 .setWaitForTimeOut(TimeValue.timeValueMillis(100))
                 .setWaitForMetadataVersion(waitForMetadataVersion);
             final ClusterStateResponse clusterStateResponse;
             try {
                 clusterStateResponse = clusterStateRequestBuilder.get();
-            } catch (MasterNotDiscoveredException e) {
+            } catch (ClusterManagerNotDiscoveredException e) {
                 return; // ok, we hit the disconnected node
             }
             if (clusterStateResponse.isWaitForTimedOut() == false) {
                 final ClusterState state = clusterStateResponse.getState();
-                assertNotNull("should always contain a master node", state.nodes().getMasterNodeId());
+                assertNotNull("should always contain a cluster-manager node", state.nodes().getClusterManagerNodeId());
                 assertThat("waited for metadata version", state.metadata().version(), greaterThanOrEqualTo(waitForMetadataVersion));
             }
         });
     }
 
     public void testLocalRequestWaitsForMetadata() throws Exception {
-        runRepeatedlyWhileChangingMaster(() -> {
+        runRepeatedlyWhileChangingClusterManager(() -> {
             final String node = randomFrom(internalCluster().getNodeNames());
             final long metadataVersion = internalCluster().getInstance(ClusterService.class, node)
                 .getClusterApplierService()
@@ -156,7 +159,7 @@ public void testLocalRequestWaitsForMetadata() throws Exception {
                 .setLocal(true)
                 .setMetadata(true)
                 .setWaitForMetadataVersion(waitForMetadataVersion)
-                .setMasterNodeTimeout(TimeValue.timeValueMillis(100))
+                .setClusterManagerNodeTimeout(TimeValue.timeValueMillis(100))
                 .setWaitForTimeOut(TimeValue.timeValueMillis(100))
                 .get();
             if (clusterStateResponse.isWaitForTimedOut() == false) {
@@ -170,7 +173,7 @@ public void testLocalRequestWaitsForMetadata() throws Exception {
         });
     }
 
-    public void runRepeatedlyWhileChangingMaster(Runnable runnable) throws Exception {
+    public void runRepeatedlyWhileChangingClusterManager(Runnable runnable) throws Exception {
         internalCluster().startNodes(3);
 
         assertBusy(
@@ -191,7 +194,7 @@ public void runRepeatedlyWhileChangingMaster(Runnable runnable) throws Exception
             )
         );
 
-        final String masterName = internalCluster().getMasterName();
+        final String clusterManagerName = internalCluster().getClusterManagerName();
 
         final AtomicBoolean shutdown = new AtomicBoolean();
         final Thread assertingThread = new Thread(() -> {
@@ -204,9 +207,12 @@ public void runRepeatedlyWhileChangingMaster(Runnable runnable) throws Exception
             String value = "none";
             while (shutdown.get() == false) {
                 value = "none".equals(value) ? "all" : "none";
-                final String nonMasterNode = randomValueOtherThan(masterName, () -> randomFrom(internalCluster().getNodeNames()));
+                final String nonClusterManagerNode = randomValueOtherThan(
+                    clusterManagerName,
+                    () -> randomFrom(internalCluster().getNodeNames())
+                );
                 assertAcked(
-                    client(nonMasterNode).admin()
+                    client(nonClusterManagerNode).admin()
                         .cluster()
                         .prepareUpdateSettings()
                         .setPersistentSettings(Settings.builder().put(CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), value))
@@ -222,22 +228,25 @@ public void runRepeatedlyWhileChangingMaster(Runnable runnable) throws Exception
         assertingThread.start();
         updatingThread.start();
 
-        final MockTransportService masterTransportService = (MockTransportService) internalCluster().getInstance(
+        final MockTransportService clusterManagerTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            masterName
+            clusterManagerName
         );
 
         for (MockTransportService mockTransportService : mockTransportServices) {
-            if (masterTransportService != mockTransportService) {
-                masterTransportService.addFailToSendNoConnectRule(mockTransportService);
-                mockTransportService.addFailToSendNoConnectRule(masterTransportService);
+            if (clusterManagerTransportService != mockTransportService) {
+                clusterManagerTransportService.addFailToSendNoConnectRule(mockTransportService);
+                mockTransportService.addFailToSendNoConnectRule(clusterManagerTransportService);
             }
         }
 
         assertBusy(() -> {
-            final String nonMasterNode = randomValueOtherThan(masterName, () -> randomFrom(internalCluster().getNodeNames()));
-            final String claimedMasterName = internalCluster().getMasterName(nonMasterNode);
-            assertThat(claimedMasterName, not(equalTo(masterName)));
+            final String nonClusterManagerNode = randomValueOtherThan(
+                clusterManagerName,
+                () -> randomFrom(internalCluster().getNodeNames())
+            );
+            final String claimedClusterManagerName = internalCluster().getClusterManagerName(nonClusterManagerNode);
+            assertThat(claimedClusterManagerName, not(equalTo(clusterManagerName)));
         });
 
         shutdown.set(true);
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIT.java
index 5b48268dfa89f..085a32593063a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIT.java
@@ -35,7 +35,9 @@
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.client.Client;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
@@ -47,12 +49,13 @@
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
@@ -82,13 +85,7 @@ private void waitForNodes(int numNodes) {
     public void testNodeCounts() {
         int total = 1;
         internalCluster().startNode();
-        Map<String, Integer> expectedCounts = new HashMap<>();
-        expectedCounts.put(DiscoveryNodeRole.DATA_ROLE.roleName(), 1);
-        expectedCounts.put(DiscoveryNodeRole.MASTER_ROLE.roleName(), 1);
-        expectedCounts.put(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName(), 1);
-        expectedCounts.put(DiscoveryNodeRole.INGEST_ROLE.roleName(), 1);
-        expectedCounts.put(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName(), 1);
-        expectedCounts.put(ClusterStatsNodes.Counts.COORDINATING_ONLY, 0);
+        Map<String, Integer> expectedCounts = getExpectedCounts(1, 1, 1, 1, 1, 0, 0);
         int numNodes = randomIntBetween(1, 5);
 
         ClusterStatsResponse response = client().admin().cluster().prepareClusterStats().get();
@@ -97,7 +94,7 @@ public void testNodeCounts() {
         for (int i = 0; i < numNodes; i++) {
             boolean isDataNode = randomBoolean();
             boolean isIngestNode = randomBoolean();
-            boolean isMasterNode = randomBoolean();
+            boolean isClusterManagerNode = randomBoolean();
             boolean isRemoteClusterClientNode = false;
             final Set<DiscoveryNodeRole> roles = new HashSet<>();
             if (isDataNode) {
@@ -106,7 +103,7 @@ public void testNodeCounts() {
             if (isIngestNode) {
                 roles.add(DiscoveryNodeRole.INGEST_ROLE);
             }
-            if (isMasterNode) {
+            if (isClusterManagerNode) {
                 roles.add(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
             }
             if (isRemoteClusterClientNode) {
@@ -128,14 +125,14 @@ public void testNodeCounts() {
             if (isIngestNode) {
                 incrementCountForRole(DiscoveryNodeRole.INGEST_ROLE.roleName(), expectedCounts);
             }
-            if (isMasterNode) {
+            if (isClusterManagerNode) {
                 incrementCountForRole(DiscoveryNodeRole.MASTER_ROLE.roleName(), expectedCounts);
                 incrementCountForRole(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName(), expectedCounts);
             }
             if (isRemoteClusterClientNode) {
                 incrementCountForRole(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName(), expectedCounts);
             }
-            if (!isDataNode && !isMasterNode && !isIngestNode && !isRemoteClusterClientNode) {
+            if (!isDataNode && !isClusterManagerNode && !isIngestNode && !isRemoteClusterClientNode) {
                 incrementCountForRole(ClusterStatsNodes.Counts.COORDINATING_ONLY, expectedCounts);
             }
 
@@ -144,6 +141,25 @@ public void testNodeCounts() {
         }
     }
 
+    // Validate assigning value "master" to setting "node.roles" can get correct count in Node Stats response after MASTER_ROLE deprecated.
+    public void testNodeCountsWithDeprecatedMasterRole() throws ExecutionException, InterruptedException {
+        int total = 1;
+        Settings settings = Settings.builder()
+            .putList(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), Collections.singletonList(DiscoveryNodeRole.MASTER_ROLE.roleName()))
+            .build();
+        internalCluster().startNode(settings);
+        waitForNodes(total);
+
+        Map<String, Integer> expectedCounts = getExpectedCounts(0, 1, 1, 0, 0, 0, 0);
+
+        Client client = client();
+        ClusterStatsResponse response = client.admin().cluster().prepareClusterStats().get();
+        assertCounts(response.getNodesStats().getCounts(), total, expectedCounts);
+
+        Set<String> expectedRoles = Set.of(DiscoveryNodeRole.MASTER_ROLE.roleName());
+        assertEquals(expectedRoles, getNodeRoles(client, 0));
+    }
+
     private static void incrementCountForRole(String role, Map<String, Integer> counts) {
         Integer count = counts.get(role);
         if (count == null) {
@@ -254,12 +270,12 @@ public void testAllocatedProcessors() throws Exception {
     }
 
     public void testClusterStatusWhenStateNotRecovered() throws Exception {
-        internalCluster().startMasterOnlyNode(Settings.builder().put("gateway.recover_after_nodes", 2).build());
+        internalCluster().startClusterManagerOnlyNode(Settings.builder().put("gateway.recover_after_nodes", 2).build());
         ClusterStatsResponse response = client().admin().cluster().prepareClusterStats().get();
         assertThat(response.getStatus(), equalTo(ClusterHealthStatus.RED));
 
         if (randomBoolean()) {
-            internalCluster().startMasterOnlyNode();
+            internalCluster().startClusterManagerOnlyNode();
         } else {
             internalCluster().startDataOnlyNode();
         }
@@ -298,4 +314,140 @@ public void testFieldTypes() {
             }
         }
     }
+
+    public void testNodeRolesWithMasterLegacySettings() throws ExecutionException, InterruptedException {
+        int total = 1;
+        Settings legacyMasterSettings = Settings.builder()
+            .put("node.master", true)
+            .put("node.data", false)
+            .put("node.ingest", false)
+            .build();
+
+        internalCluster().startNodes(legacyMasterSettings);
+        waitForNodes(total);
+
+        Map<String, Integer> expectedCounts = getExpectedCounts(0, 1, 1, 0, 1, 0, 0);
+
+        Client client = client();
+        ClusterStatsResponse clusterStatsResponse = client.admin().cluster().prepareClusterStats().get();
+        assertCounts(clusterStatsResponse.getNodesStats().getCounts(), total, expectedCounts);
+
+        Set<String> expectedRoles = Set.of(
+            DiscoveryNodeRole.MASTER_ROLE.roleName(),
+            DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName()
+        );
+        assertEquals(expectedRoles, getNodeRoles(client, 0));
+    }
+
+    public void testNodeRolesWithClusterManagerRole() throws ExecutionException, InterruptedException {
+        int total = 1;
+        Settings clusterManagerNodeRoleSettings = Settings.builder()
+            .put(
+                "node.roles",
+                String.format(
+                    Locale.ROOT,
+                    "%s, %s",
+                    DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName(),
+                    DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName()
+                )
+            )
+            .build();
+
+        internalCluster().startNodes(clusterManagerNodeRoleSettings);
+        waitForNodes(total);
+
+        Map<String, Integer> expectedCounts = getExpectedCounts(0, 1, 1, 0, 1, 0, 0);
+
+        Client client = client();
+        ClusterStatsResponse clusterStatsResponse = client.admin().cluster().prepareClusterStats().get();
+        assertCounts(clusterStatsResponse.getNodesStats().getCounts(), total, expectedCounts);
+
+        Set<String> expectedRoles = Set.of(
+            DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName(),
+            DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName()
+        );
+        assertEquals(expectedRoles, getNodeRoles(client, 0));
+    }
+
+    public void testNodeRolesWithSeedDataNodeLegacySettings() throws ExecutionException, InterruptedException {
+        int total = 1;
+        Settings legacySeedDataNodeSettings = Settings.builder()
+            .put("node.master", true)
+            .put("node.data", true)
+            .put("node.ingest", false)
+            .build();
+
+        internalCluster().startNodes(legacySeedDataNodeSettings);
+        waitForNodes(total);
+
+        Map<String, Integer> expectedRoleCounts = getExpectedCounts(1, 1, 1, 0, 1, 0, 0);
+
+        Client client = client();
+        ClusterStatsResponse clusterStatsResponse = client.admin().cluster().prepareClusterStats().get();
+        assertCounts(clusterStatsResponse.getNodesStats().getCounts(), total, expectedRoleCounts);
+
+        Set<String> expectedRoles = Set.of(
+            DiscoveryNodeRole.MASTER_ROLE.roleName(),
+            DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName(),
+            DiscoveryNodeRole.DATA_ROLE.roleName()
+        );
+        assertEquals(expectedRoles, getNodeRoles(client, 0));
+    }
+
+    public void testNodeRolesWithDataNodeLegacySettings() throws ExecutionException, InterruptedException {
+        int total = 2;
+        Settings legacyDataNodeSettings = Settings.builder()
+            .put("node.master", false)
+            .put("node.data", true)
+            .put("node.ingest", false)
+            .build();
+
+        // can't start data-only node without assigning cluster-manager
+        internalCluster().startClusterManagerOnlyNodes(1);
+        internalCluster().startNodes(legacyDataNodeSettings);
+        waitForNodes(total);
+
+        Map<String, Integer> expectedRoleCounts = getExpectedCounts(1, 1, 1, 0, 1, 0, 0);
+
+        Client client = client();
+        ClusterStatsResponse clusterStatsResponse = client.admin().cluster().prepareClusterStats().get();
+        assertCounts(clusterStatsResponse.getNodesStats().getCounts(), total, expectedRoleCounts);
+
+        Set<Set<String>> expectedNodesRoles = Set.of(
+            Set.of(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName()),
+            Set.of(DiscoveryNodeRole.DATA_ROLE.roleName(), DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName())
+        );
+        assertEquals(expectedNodesRoles, Set.of(getNodeRoles(client, 0), getNodeRoles(client, 1)));
+    }
+
+    private Map<String, Integer> getExpectedCounts(
+        int dataRoleCount,
+        int masterRoleCount,
+        int clusterManagerRoleCount,
+        int ingestRoleCount,
+        int remoteClusterClientRoleCount,
+        int searchRoleCount,
+        int coordinatingOnlyCount
+    ) {
+        Map<String, Integer> expectedCounts = new HashMap<>();
+        expectedCounts.put(DiscoveryNodeRole.DATA_ROLE.roleName(), dataRoleCount);
+        expectedCounts.put(DiscoveryNodeRole.MASTER_ROLE.roleName(), masterRoleCount);
+        expectedCounts.put(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleName(), clusterManagerRoleCount);
+        expectedCounts.put(DiscoveryNodeRole.INGEST_ROLE.roleName(), ingestRoleCount);
+        expectedCounts.put(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE.roleName(), remoteClusterClientRoleCount);
+        expectedCounts.put(DiscoveryNodeRole.SEARCH_ROLE.roleName(), searchRoleCount);
+        expectedCounts.put(ClusterStatsNodes.Counts.COORDINATING_ONLY, coordinatingOnlyCount);
+        return expectedCounts;
+    }
+
+    private Set<String> getNodeRoles(Client client, int nodeNumber) throws ExecutionException, InterruptedException {
+        NodesStatsResponse nodesStatsResponse = client.admin().cluster().nodesStats(new NodesStatsRequest()).get();
+        return nodesStatsResponse.getNodes()
+            .get(nodeNumber)
+            .getNode()
+            .getRoles()
+            .stream()
+            .map(DiscoveryNodeRole::roleName)
+            .collect(Collectors.toSet());
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/tasks/PendingTasksBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/tasks/PendingTasksBlocksIT.java
index 8484cce1045d2..83aa744a80599 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/tasks/PendingTasksBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/tasks/PendingTasksBlocksIT.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.gateway.GatewayService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Arrays;
 
@@ -91,7 +91,7 @@ public void testPendingTasksWithClusterNotRecoveredBlock() throws Exception {
         }
 
         // restart the cluster but prevent it from performing state recovery
-        final int nodeCount = client().admin().cluster().prepareNodesInfo("data:true", "master:true").get().getNodes().size();
+        final int nodeCount = client().admin().cluster().prepareNodesInfo("data:true", "cluster_manager:true").get().getNodes().size();
         internalCluster().fullRestart(new InternalTestCluster.RestartCallback() {
             @Override
             public Settings onNodeStopped(String nodeName) {
@@ -107,7 +107,7 @@ public boolean validateClusterForming() {
         assertNotNull(client().admin().cluster().preparePendingClusterTasks().get().getPendingTasks());
 
         // starting one more node allows the cluster to recover
-        internalCluster().startDataOnlyNode(); // cannot update minimum_master_nodes before the cluster has formed
+        internalCluster().startDataOnlyNode(); // cannot update minimum_cluster_manager_nodes before the cluster has formed
         ensureGreen();
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/alias/ValidateIndicesAliasesRequestIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/alias/ValidateIndicesAliasesRequestIT.java
index 60243bd52ded3..910a9d351d83a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/alias/ValidateIndicesAliasesRequestIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/alias/ValidateIndicesAliasesRequestIT.java
@@ -33,16 +33,16 @@
 package org.opensearch.action.admin.indices.alias;
 
 import org.opensearch.action.RequestValidators;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistResponse;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -108,8 +108,8 @@ public void testAllowed() {
         request.addAliasAction(IndicesAliasesRequest.AliasActions.add().index("index").alias("alias"));
         assertAcked(client().admin().indices().aliases(request).actionGet());
         final GetAliasesResponse response = client().admin().indices().getAliases(new GetAliasesRequest("alias")).actionGet();
-        assertThat(response.getAliases().keys().size(), equalTo(1));
-        assertThat(response.getAliases().keys().iterator().next().value, equalTo("index"));
+        assertThat(response.getAliases().keySet().size(), equalTo(1));
+        assertThat(response.getAliases().keySet().iterator().next(), equalTo("index"));
         final List<AliasMetadata> aliasMetadata = response.getAliases().get("index");
         assertThat(aliasMetadata, hasSize(1));
         assertThat(aliasMetadata.get(0).alias(), equalTo("alias"));
@@ -143,8 +143,6 @@ public void testSomeAllowed() {
         final Exception e = expectThrows(IllegalStateException.class, () -> client().admin().indices().aliases(request).actionGet());
         final String index = "foo_allowed".equals(origin) ? "bar" : "foo";
         assertThat(e, hasToString(containsString("origin [" + origin + "] not allowed for index [" + index + "]")));
-        final AliasesExistResponse response = client().admin().indices().aliasesExist(new GetAliasesRequest("alias")).actionGet();
-        assertFalse(response.exists());
+        assertTrue(client().admin().indices().getAliases(new GetAliasesRequest("alias")).actionGet().getAliases().isEmpty());
     }
-
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheBlocksIT.java
index 126bb57501abb..31c1aca53ae4a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheBlocksIT.java
@@ -36,6 +36,7 @@
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 
 import java.util.Arrays;
+import java.util.Collections;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_METADATA;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_READ;
@@ -55,7 +56,12 @@ public void testClearIndicesCacheWithBlocks() {
         NumShards numShards = getNumShards("test");
 
         // Request is not blocked
-        for (String blockSetting : Arrays.asList(SETTING_BLOCKS_READ, SETTING_BLOCKS_WRITE)) {
+        for (String blockSetting : Arrays.asList(
+            SETTING_BLOCKS_READ,
+            SETTING_BLOCKS_WRITE,
+            SETTING_READ_ONLY,
+            SETTING_READ_ONLY_ALLOW_DELETE
+        )) {
             try {
                 enableIndexBlock("test", blockSetting);
                 ClearIndicesCacheResponse clearIndicesCacheResponse = client().admin()
@@ -73,7 +79,7 @@ public void testClearIndicesCacheWithBlocks() {
             }
         }
         // Request is blocked
-        for (String blockSetting : Arrays.asList(SETTING_READ_ONLY, SETTING_BLOCKS_METADATA, SETTING_READ_ONLY_ALLOW_DELETE)) {
+        for (String blockSetting : Arrays.asList(SETTING_BLOCKS_METADATA)) {
             try {
                 enableIndexBlock("test", blockSetting);
                 assertBlocked(
@@ -84,4 +90,42 @@ public void testClearIndicesCacheWithBlocks() {
             }
         }
     }
+
+    public void testClearIndicesFileCacheWithBlocks() {
+        createIndex("test");
+        ensureGreen("test");
+
+        NumShards numShards = getNumShards("test");
+
+        // Request is not blocked
+        for (String blockSetting : Arrays.asList(
+            SETTING_BLOCKS_READ,
+            SETTING_BLOCKS_WRITE,
+            SETTING_READ_ONLY,
+            SETTING_READ_ONLY_ALLOW_DELETE
+        )) {
+            try {
+                enableIndexBlock("test", blockSetting);
+                ClearIndicesCacheResponse clearIndicesCacheResponse = client().admin()
+                    .indices()
+                    .prepareClearCache("test")
+                    .setFileCache(true)
+                    .execute()
+                    .actionGet();
+                assertNoFailures(clearIndicesCacheResponse);
+                assertThat(clearIndicesCacheResponse.getSuccessfulShards(), equalTo(numShards.totalNumShards));
+            } finally {
+                disableIndexBlock("test", blockSetting);
+            }
+        }
+
+        for (String blockSetting : Collections.singletonList(SETTING_BLOCKS_METADATA)) {
+            try {
+                enableIndexBlock("test", blockSetting);
+                assertBlocked(client().admin().indices().prepareClearCache("test").setQueryCache(true).setFileCache(true));
+            } finally {
+                disableIndexBlock("test", blockSetting);
+            }
+        }
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CloneIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CloneIndexIT.java
index 98fc6483703c4..0551d19b02b8f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CloneIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CloneIndexIT.java
@@ -37,7 +37,7 @@
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.TermsQueryBuilder;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -62,7 +62,7 @@ public void testCreateCloneIndex() {
         ).get();
         final int docs = randomIntBetween(0, 128);
         for (int i = 0; i < docs; i++) {
-            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         internalCluster().ensureAtLeastNumDataNodes(2);
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
@@ -122,7 +122,7 @@ public void testCreateCloneIndex() {
             }
 
             for (int i = docs; i < 2 * docs; i++) {
-                client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+                client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
             }
             flushAndRefresh();
             assertHitCount(
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CreateIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CreateIndexIT.java
index 3ef2a63c7d0ac..d0f4c98444b2e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CreateIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/CreateIndexIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.indices.create;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.action.admin.indices.alias.Alias;
@@ -45,10 +44,10 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperParsingException;
@@ -59,6 +58,7 @@
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
 
+import java.util.Map;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiFunction;
@@ -100,7 +100,7 @@ public void testCreationDateGenerated() {
         assertThat(state, notNullValue());
         Metadata metadata = state.getMetadata();
         assertThat(metadata, notNullValue());
-        ImmutableOpenMap<String, IndexMetadata> indices = metadata.getIndices();
+        final Map<String, IndexMetadata> indices = metadata.getIndices();
         assertThat(indices, notNullValue());
         assertThat(indices.size(), equalTo(1));
         IndexMetadata index = indices.get("test");
@@ -340,7 +340,7 @@ public void testFailureToCreateIndexCleansUpIndicesService() {
             IllegalStateException.class
         );
 
-        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, internalCluster().getMasterName());
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, internalCluster().getClusterManagerName());
         for (IndexService indexService : indicesService) {
             assertThat(indexService.index().getName(), not("test-idx-2"));
         }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/ShrinkIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/ShrinkIndexIT.java
index e8a6c68a41076..cafcb73b699fc 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/ShrinkIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/ShrinkIndexIT.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.search.SortedSetSelector;
 import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.util.Constants;
-
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
@@ -64,19 +63,19 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.Priority;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.SegmentsStats;
 import org.opensearch.index.query.TermsQueryBuilder;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.util.Arrays;
@@ -109,18 +108,12 @@ public void testCreateShrinkIndexToN() {
         for (int i = 0; i < 20; i++) {
             client().prepareIndex("source")
                 .setId(Integer.toString(i))
-                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON)
                 .get();
         }
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
         assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
-        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         String mergeNode = discoveryNodes[0].getName();
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
         // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
@@ -153,7 +146,7 @@ public void testCreateShrinkIndexToN() {
         for (int i = 0; i < 20; i++) { // now update
             client().prepareIndex("first_shrink")
                 .setId(Integer.toString(i))
-                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON)
                 .get();
         }
         flushAndRefresh();
@@ -196,7 +189,7 @@ public void testCreateShrinkIndexToN() {
         for (int i = 0; i < 20; i++) { // now update
             client().prepareIndex("second_shrink")
                 .setId(Integer.toString(i))
-                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON)
                 .get();
         }
         flushAndRefresh();
@@ -211,15 +204,9 @@ public void testShrinkIndexPrimaryTerm() throws Exception {
         internalCluster().ensureAtLeastNumDataNodes(2);
         prepareCreate("source").setSettings(Settings.builder().put(indexSettings()).put("number_of_shards", numberOfShards)).get();
 
-        final ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
         assertThat(dataNodes.size(), greaterThanOrEqualTo(2));
-        final DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        final DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         final String mergeNode = discoveryNodes[0].getName();
         // This needs more than the default timeout if a large number of shards were created.
         ensureGreen(TimeValue.timeValueSeconds(120));
@@ -244,7 +231,7 @@ public void testShrinkIndexPrimaryTerm() throws Exception {
                         final int hash = Math.floorMod(Murmur3HashFunction.hash(s), numberOfShards);
                         if (hash == shardId) {
                             final IndexRequest request = new IndexRequest("source").id(s)
-                                .source("{ \"f\": \"" + s + "\"}", XContentType.JSON);
+                                .source("{ \"f\": \"" + s + "\"}", MediaTypeRegistry.JSON);
                             client().index(request).get();
                             break;
                         } else {
@@ -295,17 +282,11 @@ public void testCreateShrinkIndex() {
         ).get();
         final int docs = randomIntBetween(0, 128);
         for (int i = 0; i < docs; i++) {
-            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
         assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
-        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
         // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
         // to the require._name below.
@@ -396,7 +377,7 @@ public void testCreateShrinkIndex() {
         }
 
         for (int i = docs; i < 2 * docs; i++) {
-            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         flushAndRefresh();
         assertHitCount(client().prepareSearch("target").setSize(2 * size).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 2 * docs);
@@ -423,17 +404,11 @@ public void testCreateShrinkIndexFails() throws Exception {
             Settings.builder().put(indexSettings()).put("number_of_shards", randomIntBetween(2, 7)).put("number_of_replicas", 0)
         ).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
         assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
-        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         String spareNode = discoveryNodes[0].getName();
         String mergeNode = discoveryNodes[1].getName();
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
@@ -496,7 +471,7 @@ public void testCreateShrinkIndexFails() throws Exception {
 
         final InternalClusterInfoService infoService = (InternalClusterInfoService) internalCluster().getInstance(
             ClusterInfoService.class,
-            internalCluster().getMasterName()
+            internalCluster().getClusterManagerName()
         );
         infoService.refresh();
         // kick off a retry and wait until it's done!
@@ -530,18 +505,12 @@ public void testCreateShrinkWithIndexSort() throws Exception {
         for (int i = 0; i < 20; i++) {
             client().prepareIndex("source")
                 .setId(Integer.toString(i))
-                .setSource("{\"foo\" : \"bar\", \"id\" : " + i + "}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\", \"id\" : " + i + "}", MediaTypeRegistry.JSON)
                 .get();
         }
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
         assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
-        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         String mergeNode = discoveryNodes[0].getName();
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
         // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
@@ -599,7 +568,7 @@ public void testCreateShrinkWithIndexSort() throws Exception {
 
         // ... and that the index sort is also applied to updates
         for (int i = 20; i < 40; i++) {
-            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         flushAndRefresh();
         assertSortedSegments("target", expectedIndexSort);
@@ -610,17 +579,11 @@ public void testShrinkCommitsMergeOnIdle() throws Exception {
             Settings.builder().put(indexSettings()).put("index.number_of_replicas", 0).put("number_of_shards", 5)
         ).get();
         for (int i = 0; i < 30; i++) {
-            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         client().admin().indices().prepareFlush("source").get();
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin()
-            .cluster()
-            .prepareState()
-            .get()
-            .getState()
-            .nodes()
-            .getDataNodes();
-        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(DiscoveryNode.class);
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
         // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
         // to the require._name below.
@@ -760,4 +723,72 @@ public void testShrinkThenSplitWithFailedNode() throws Exception {
         );
         ensureGreen("splitagain");
     }
+
+    public void testCreateShrinkIndexWithMaxShardSize() {
+        internalCluster().ensureAtLeastNumDataNodes(2);
+        final String shrinkNode = internalCluster().startDataOnlyNode();
+
+        final int shardCount = between(2, 5);
+        prepareCreate("source").setSettings(
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, shardCount)
+        ).get();
+        for (int i = 0; i < 20; i++) {
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
+        }
+        client().admin().indices().prepareFlush("source").get();
+        ensureGreen();
+
+        client().admin()
+            .indices()
+            .prepareUpdateSettings("source")
+            .setSettings(
+                Settings.builder()
+                    .put(IndexMetadata.INDEX_ROUTING_REQUIRE_GROUP_SETTING.getConcreteSettingForNamespace("_name").getKey(), shrinkNode)
+                    .put(IndexMetadata.SETTING_BLOCKS_WRITE, true)
+            )
+            .get();
+        ensureGreen();
+
+        // Cannot set max_shard_size and index.number_of_shards at the same time
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .indices()
+                .prepareResizeIndex("source", "target")
+                .setSettings(
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                        .build()
+                )
+                .setMaxShardSize(new ByteSizeValue(1))
+                .setResizeType(ResizeType.SHRINK)
+                .get()
+        );
+        assertTrue(exc.getMessage().contains("Cannot set max_shard_size and index.number_of_shards at the same time!"));
+
+        // use max_shard_size to calculate the target index's shards number
+        // set max_shard_size to 1 then the target index's shards number will be same with the source index's
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareResizeIndex("source", "target")
+                .setSettings(
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                        .putNull(IndexMetadata.INDEX_ROUTING_REQUIRE_GROUP_SETTING.getConcreteSettingForNamespace("_name").getKey())
+                        .build()
+                )
+                .setMaxShardSize(new ByteSizeValue(1))
+                .setResizeType(ResizeType.SHRINK)
+                .get()
+        );
+        ensureGreen();
+
+        GetSettingsResponse target = client().admin().indices().prepareGetSettings("target").get();
+        assertEquals(String.valueOf(shardCount), target.getIndexToSettings().get("target").get("index.number_of_shards"));
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/SplitIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/SplitIndexIT.java
index 89e11984621da..c8b151e24ce98 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/SplitIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/create/SplitIndexIT.java
@@ -38,7 +38,6 @@
 import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.util.Constants;
-
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
@@ -61,8 +60,8 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.SegmentsStats;
 import org.opensearch.index.query.TermsQueryBuilder;
@@ -347,7 +346,7 @@ public void testSplitIndexPrimaryTerm() throws Exception {
                         final int hash = Math.floorMod(Murmur3HashFunction.hash(s), numberOfShards);
                         if (hash == shardId) {
                             final IndexRequest request = new IndexRequest("source").id(s)
-                                .source("{ \"f\": \"" + s + "\"}", XContentType.JSON);
+                                .source("{ \"f\": \"" + s + "\"}", MediaTypeRegistry.JSON);
                             client().index(request).get();
                             break;
                         } else {
@@ -403,7 +402,7 @@ public void testCreateSplitIndex() throws Exception {
         ).get();
         final int docs = randomIntBetween(0, 128);
         for (int i = 0; i < docs; i++) {
-            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("source").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
         // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
@@ -487,7 +486,7 @@ public void testCreateSplitIndex() throws Exception {
             }
 
             for (int i = docs; i < 2 * docs; i++) {
-                client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+                client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
             }
             flushAndRefresh();
             assertHitCount(
@@ -526,7 +525,7 @@ public void testCreateSplitWithIndexSort() throws Exception {
         for (int i = 0; i < 20; i++) {
             client().prepareIndex("source")
                 .setId(Integer.toString(i))
-                .setSource("{\"foo\" : \"bar\", \"id\" : " + i + "}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\", \"id\" : " + i + "}", MediaTypeRegistry.JSON)
                 .get();
         }
         // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
@@ -582,7 +581,7 @@ public void testCreateSplitWithIndexSort() throws Exception {
 
         // ... and that the index sort is also applied to updates
         for (int i = 20; i < 40; i++) {
-            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
+            client().prepareIndex("target").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
         }
         flushAndRefresh();
         assertSortedSegments("target", expectedIndexSort);
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamIndexTemplateIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamIndexTemplateIT.java
index ed500d72c3787..08f7fb17e5164 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamIndexTemplateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamIndexTemplateIT.java
@@ -8,8 +8,7 @@
 
 package org.opensearch.action.admin.indices.datastream;
 
-import org.opensearch.common.collect.List;
-
+import java.util.List;
 import java.util.concurrent.ExecutionException;
 
 import static org.hamcrest.Matchers.containsString;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamRolloverIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamRolloverIT.java
index bac16dd4b7cc0..6afa48da0918e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamRolloverIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamRolloverIT.java
@@ -10,7 +10,7 @@
 
 import org.opensearch.action.admin.indices.rollover.RolloverResponse;
 import org.opensearch.cluster.metadata.DataStream;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Collections;
 import java.util.stream.Collectors;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamTestCase.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamTestCase.java
index 7b0d917504a2f..50ff76c6b62f3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamTestCase.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamTestCase.java
@@ -16,19 +16,19 @@
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.cluster.metadata.Template;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.List;
 import java.util.stream.Collectors;
 
-import static org.hamcrest.Matchers.is;
 import static org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import static org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import static org.hamcrest.Matchers.is;
 
 @ClusterScope(scope = Scope.TEST, numDataNodes = 2)
 public class DataStreamTestCase extends OpenSearchIntegTestCase {
@@ -90,7 +90,7 @@ public AcknowledgedResponse createDataStreamIndexTemplate(String name, List<Stri
     }
 
     public AcknowledgedResponse createIndexTemplate(String name, String jsonContent) throws Exception {
-        XContentParser parser = XContentHelper.createParser(xContentRegistry(), null, new BytesArray(jsonContent), XContentType.JSON);
+        XContentParser parser = XContentHelper.createParser(xContentRegistry(), null, new BytesArray(jsonContent), MediaTypeRegistry.JSON);
 
         return createIndexTemplate(name, ComposableIndexTemplate.parse(parser));
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamUsageIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamUsageIT.java
index 785be061135f0..deabbe44bfc3d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamUsageIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/datastream/DataStreamUsageIT.java
@@ -13,12 +13,12 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.cluster.metadata.DataStream;
-import org.opensearch.common.collect.List;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 
 import java.util.Arrays;
+import java.util.List;
 import java.util.concurrent.ExecutionException;
 import java.util.stream.Collectors;
 
@@ -93,13 +93,18 @@ public void assertDataStreamIndexDocuments(String timestampFieldName) throws Exc
         Exception exception;
 
         // Only op_type=create requests should be allowed.
-        exception = expectThrows(Exception.class, () -> index(new IndexRequest("logs-demo").id("doc-1").source("{}", XContentType.JSON)));
+        exception = expectThrows(
+            Exception.class,
+            () -> index(new IndexRequest("logs-demo").id("doc-1").source("{}", MediaTypeRegistry.JSON))
+        );
         assertThat(exception.getMessage(), containsString("only write ops with an op_type of create are allowed in data streams"));
 
         // Documents must contain a valid timestamp field.
         exception = expectThrows(
             Exception.class,
-            () -> index(new IndexRequest("logs-demo").id("doc-1").source("{}", XContentType.JSON).opType(DocWriteRequest.OpType.CREATE))
+            () -> index(
+                new IndexRequest("logs-demo").id("doc-1").source("{}", MediaTypeRegistry.JSON).opType(DocWriteRequest.OpType.CREATE)
+            )
         );
         assertThat(
             exception.getMessage(),
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/exists/IndicesExistsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/exists/IndicesExistsIT.java
index f8be80948f8cf..b5ab4b5290171 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/exists/IndicesExistsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/exists/IndicesExistsIT.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.discovery.MasterNotDiscoveredException;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
 import org.opensearch.gateway.GatewayService;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.InternalTestCluster;
 
 import java.io.IOException;
 
@@ -48,13 +48,13 @@
 public class IndicesExistsIT extends OpenSearchIntegTestCase {
 
     public void testIndexExistsWithBlocksInPlace() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         Settings settings = Settings.builder().put(GatewayService.RECOVER_AFTER_NODES_SETTING.getKey(), 99).build();
         String node = internalCluster().startNode(settings);
 
         assertRequestBuilderThrows(
-            client(node).admin().indices().prepareExists("test").setMasterNodeTimeout(TimeValue.timeValueSeconds(0)),
-            MasterNotDiscoveredException.class
+            client(node).admin().indices().prepareExists("test").setClusterManagerNodeTimeout(TimeValue.timeValueSeconds(0)),
+            ClusterManagerNotDiscoveredException.class
         );
 
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(node)); // shut down node so that test properly cleans up
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeIT.java
index 195817bf04cc9..09af533292e9a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeIT.java
@@ -40,7 +40,7 @@
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/get/GetIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/get/GetIndexIT.java
index ffc738ac98de5..e5db895e7dfa9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/get/GetIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/get/GetIndexIT.java
@@ -32,13 +32,11 @@
 
 package org.opensearch.action.admin.indices.get;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.get.GetIndexRequest.Feature;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -46,6 +44,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_METADATA_BLOCK;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_BLOCKS_METADATA;
@@ -254,7 +253,7 @@ private GetIndexResponse runWithRandomFeatureMethod(GetIndexRequestBuilder reque
     }
 
     private void assertSettings(GetIndexResponse response, String indexName) {
-        ImmutableOpenMap<String, Settings> settings = response.settings();
+        final Map<String, Settings> settings = response.settings();
         assertThat(settings, notNullValue());
         assertThat(settings.size(), equalTo(1));
         Settings indexSettings = settings.get(indexName);
@@ -263,7 +262,7 @@ private void assertSettings(GetIndexResponse response, String indexName) {
     }
 
     private void assertNonEmptySettings(GetIndexResponse response, String indexName) {
-        ImmutableOpenMap<String, Settings> settings = response.settings();
+        final Map<String, Settings> settings = response.settings();
         assertThat(settings, notNullValue());
         assertThat(settings.size(), equalTo(1));
         Settings indexSettings = settings.get(indexName);
@@ -271,7 +270,7 @@ private void assertNonEmptySettings(GetIndexResponse response, String indexName)
     }
 
     private void assertMappings(GetIndexResponse response, String indexName) {
-        ImmutableOpenMap<String, MappingMetadata> mappings = response.mappings();
+        final Map<String, MappingMetadata> mappings = response.mappings();
         assertThat(mappings, notNullValue());
         assertThat(mappings.size(), equalTo(1));
         MappingMetadata indexMappings = mappings.get(indexName);
@@ -279,7 +278,7 @@ private void assertMappings(GetIndexResponse response, String indexName) {
     }
 
     private void assertEmptyOrOnlyDefaultMappings(GetIndexResponse response, String indexName) {
-        ImmutableOpenMap<String, MappingMetadata> mappings = response.mappings();
+        final Map<String, MappingMetadata> mappings = response.mappings();
         assertThat(mappings, notNullValue());
         assertThat(mappings.size(), equalTo(1));
         MappingMetadata indexMappings = mappings.get(indexName);
@@ -287,7 +286,7 @@ private void assertEmptyOrOnlyDefaultMappings(GetIndexResponse response, String
     }
 
     private void assertAliases(GetIndexResponse response, String indexName) {
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = response.aliases();
+        final Map<String, List<AliasMetadata>> aliases = response.aliases();
         assertThat(aliases, notNullValue());
         assertThat(aliases.size(), equalTo(1));
         List<AliasMetadata> indexAliases = aliases.get(indexName);
@@ -310,8 +309,8 @@ private void assertEmptyMappings(GetIndexResponse response) {
 
     private void assertEmptyAliases(GetIndexResponse response) {
         assertThat(response.aliases(), notNullValue());
-        for (final ObjectObjectCursor<String, List<AliasMetadata>> entry : response.getAliases()) {
-            assertTrue(entry.value.isEmpty());
+        for (final List<AliasMetadata> entry : response.getAliases().values()) {
+            assertTrue(entry.isEmpty());
         }
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/mapping/put/ValidateMappingRequestPluginIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/mapping/put/ValidateMappingRequestPluginIT.java
index fe1bc05dc5f20..ee516a53fadef 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/mapping/put/ValidateMappingRequestPluginIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/mapping/put/ValidateMappingRequestPluginIT.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.RequestValidators;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/rollover/RolloverIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/rollover/RolloverIT.java
index 178dc2c6ffa87..d4e07aa4251c3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/rollover/RolloverIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/rollover/RolloverIT.java
@@ -35,10 +35,10 @@
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
+import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequestBuilder;
 import org.opensearch.action.admin.indices.template.put.PutIndexTemplateRequestBuilder;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.AutoExpandReplicas;
@@ -46,13 +46,13 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
@@ -64,6 +64,7 @@
 import static org.opensearch.index.mapper.MapperService.SINGLE_MAPPING_NAME;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.everyItem;
 import static org.hamcrest.Matchers.is;
@@ -172,6 +173,7 @@ public void testRolloverWithNoWriteIndex() {
     }
 
     public void testRolloverWithIndexSettings() throws Exception {
+
         Alias testAlias = new Alias("test_alias");
         boolean explicitWriteIndex = randomBoolean();
         if (explicitWriteIndex) {
@@ -210,6 +212,118 @@ public void testRolloverWithIndexSettings() throws Exception {
         }
     }
 
+    public void testRolloverWithIndexSettingsBalancedReplica() throws Exception {
+        Alias testAlias = new Alias("test_alias");
+        boolean explicitWriteIndex = randomBoolean();
+        if (explicitWriteIndex) {
+            testAlias.writeIndex(true);
+        }
+        assertAcked(prepareCreate("test_index-2").addAlias(testAlias).get());
+        manageReplicaBalanceSetting(true);
+        index("test_index-2", "type1", "1", "field", "value");
+        flush("test_index-2");
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .build();
+
+        final IllegalArgumentException restoreError = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareRolloverIndex("test_alias").settings(settings).alias(new Alias("extra_alias")).get()
+        );
+
+        assertThat(
+            restoreError.getMessage(),
+            containsString("expected total copies needs to be a multiple of total awareness attributes [2]")
+        );
+
+        client().admin()
+            .indices()
+            .prepareRolloverIndex("test_alias")
+            .settings(
+                Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1).build()
+            )
+            .alias(new Alias("extra_alias"))
+            .waitForActiveShards(0)
+            .get();
+
+        client().admin()
+            .indices()
+            .prepareRolloverIndex("test_alias")
+            .settings(
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+                    .build()
+            )
+            .alias(new Alias("extra_alias"))
+            .waitForActiveShards(0)
+            .get();
+
+        client().admin()
+            .indices()
+            .prepareRolloverIndex("test_alias")
+            .settings(
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-all")
+                    .build()
+            )
+            .alias(new Alias("extra_alias"))
+            .waitForActiveShards(0)
+            .get();
+
+        final IllegalArgumentException restoreError2 = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .indices()
+                .prepareRolloverIndex("test_alias")
+                .settings(
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+                        .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-0")
+                        .build()
+                )
+                .alias(new Alias("extra_alias"))
+                .get()
+        );
+
+        assertThat(
+            restoreError2.getMessage(),
+            containsString("expected max cap on auto expand to be a multiple of total awareness attributes [2]")
+        );
+
+        manageReplicaBalanceSetting(false);
+    }
+
+    public void testRolloverWithIndexSettingsBalancedWithUseZoneForReplicaDefaultCount() throws Exception {
+        DeleteIndexTemplateRequestBuilder deleteTemplate = client().admin().indices().prepareDeleteTemplate("random_index_template");
+        assertAcked(deleteTemplate.execute().actionGet());
+
+        Alias testAlias = new Alias("test_alias");
+        boolean explicitWriteIndex = randomBoolean();
+        if (explicitWriteIndex) {
+            testAlias.writeIndex(true);
+        }
+        assertAcked(prepareCreate("test_index-2").addAlias(testAlias).get());
+        manageReplicaSettingForDefaultReplica(true);
+        index("test_index-2", "type1", "1", "field", "value");
+        flush("test_index-2");
+
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3).build();
+        client().admin().indices().prepareRolloverIndex("test_alias").settings(settings).alias(new Alias("extra_alias")).get();
+
+        final ClusterState state = client().admin().cluster().prepareState().get().getState();
+        final IndexMetadata newIndex = state.metadata().index("test_index-000003");
+        assertThat(newIndex.getNumberOfShards(), equalTo(3));
+        assertThat(newIndex.getNumberOfReplicas(), equalTo(2));
+        manageReplicaSettingForDefaultReplica(false);
+        randomIndexTemplate();
+    }
+
     public void testRolloverWithIndexSettingsWithoutPrefix() throws Exception {
         Alias testAlias = new Alias("test_alias");
         boolean explicitWriteIndex = randomBoolean();
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestIT.java
index ea9f7e0a7232d..fe5ec9227e844 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestIT.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.action.admin.indices.shards;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.lucene.index.CorruptIndexException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.client.Requests;
@@ -42,10 +40,8 @@
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
@@ -102,10 +98,10 @@ public void testBasic() throws Exception {
         // all shards
         response = client().admin().indices().shardStores(Requests.indicesShardStoresRequest(index).shardStatuses("all")).get();
         assertThat(response.getStoreStatuses().containsKey(index), equalTo(true));
-        ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> shardStores = response.getStoreStatuses().get(index);
+        final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> shardStores = response.getStoreStatuses().get(index);
         assertThat(shardStores.values().size(), equalTo(2));
-        for (ObjectCursor<List<IndicesShardStoresResponse.StoreStatus>> shardStoreStatuses : shardStores.values()) {
-            for (IndicesShardStoresResponse.StoreStatus storeStatus : shardStoreStatuses.value) {
+        for (var shardStoreStatuses : shardStores.values()) {
+            for (IndicesShardStoresResponse.StoreStatus storeStatus : shardStoreStatuses) {
                 assertThat(storeStatus.getAllocationId(), notNullValue());
                 assertThat(storeStatus.getNode(), notNullValue());
                 assertThat(storeStatus.getStoreException(), nullValue());
@@ -124,13 +120,13 @@ public void testBasic() throws Exception {
         List<ShardRouting> unassignedShards = clusterState.routingTable().index(index).shardsWithState(ShardRoutingState.UNASSIGNED);
         response = client().admin().indices().shardStores(Requests.indicesShardStoresRequest(index)).get();
         assertThat(response.getStoreStatuses().containsKey(index), equalTo(true));
-        ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> shardStoresStatuses = response.getStoreStatuses().get(index);
+        final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> shardStoresStatuses = response.getStoreStatuses().get(index);
         assertThat(shardStoresStatuses.size(), equalTo(unassignedShards.size()));
-        for (IntObjectCursor<List<IndicesShardStoresResponse.StoreStatus>> storesStatus : shardStoresStatuses) {
-            assertThat("must report for one store", storesStatus.value.size(), equalTo(1));
+        for (var storesStatus : shardStoresStatuses.values()) {
+            assertThat("must report for one store", storesStatus.size(), equalTo(1));
             assertThat(
                 "reported store should be primary",
-                storesStatus.value.get(0).getAllocationStatus(),
+                storesStatus.get(0).getAllocationStatus(),
                 equalTo(IndicesShardStoresResponse.StoreStatus.AllocationStatus.PRIMARY)
             );
         }
@@ -151,8 +147,7 @@ public void testIndices() throws Exception {
             .indices()
             .shardStores(Requests.indicesShardStoresRequest().shardStatuses("all"))
             .get();
-        ImmutableOpenMap<String, ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>>> shardStatuses = response
-            .getStoreStatuses();
+        Map<String, Map<Integer, List<IndicesShardStoresResponse.StoreStatus>>> shardStatuses = response.getStoreStatuses();
         assertThat(shardStatuses.containsKey(index1), equalTo(true));
         assertThat(shardStatuses.containsKey(index2), equalTo(true));
         assertThat(shardStatuses.get(index1).size(), equalTo(2));
@@ -207,21 +202,21 @@ public void testCorruptedShards() throws Exception {
 
         assertBusy(() -> { // IndicesClusterStateService#failAndRemoveShard() called asynchronously but we need it to have completed here.
             IndicesShardStoresResponse rsp = client().admin().indices().prepareShardStores(index).setShardStatuses("all").get();
-            ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> shardStatuses = rsp.getStoreStatuses().get(index);
+            final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> shardStatuses = rsp.getStoreStatuses().get(index);
             assertNotNull(shardStatuses);
             assertThat(shardStatuses.size(), greaterThan(0));
-            for (IntObjectCursor<List<IndicesShardStoresResponse.StoreStatus>> shardStatus : shardStatuses) {
-                for (IndicesShardStoresResponse.StoreStatus status : shardStatus.value) {
-                    if (corruptedShardIDMap.containsKey(shardStatus.key)
-                        && corruptedShardIDMap.get(shardStatus.key).contains(status.getNode().getName())) {
+            for (var shardStatus : shardStatuses.entrySet()) {
+                for (IndicesShardStoresResponse.StoreStatus status : shardStatus.getValue()) {
+                    if (corruptedShardIDMap.containsKey(shardStatus.getKey())
+                        && corruptedShardIDMap.get(shardStatus.getKey()).contains(status.getNode().getName())) {
                         assertThat(
-                            "shard [" + shardStatus.key + "] is failed on node [" + status.getNode().getName() + "]",
+                            "shard [" + shardStatus.getKey() + "] is failed on node [" + status.getNode().getName() + "]",
                             status.getStoreException(),
                             notNullValue()
                         );
                     } else {
                         assertNull(
-                            "shard [" + shardStatus.key + "] is not failed on node [" + status.getNode().getName() + "]",
+                            "shard [" + shardStatus.getKey() + "] is not failed on node [" + status.getNode().getName() + "]",
                             status.getStoreException()
                         );
                     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkIntegrationIT.java
index e2a1363f163da..cf83f20244a4b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkIntegrationIT.java
@@ -37,19 +37,19 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse;
-
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.ingest.PutPipelineRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.action.support.replication.ReplicationRequest;
+import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.IngestTestPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
@@ -83,7 +83,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     public void testBulkIndexCreatesMapping() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/bulk-log.json");
         BulkRequestBuilder bulkBuilder = client().prepareBulk();
-        bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         bulkBuilder.get();
         assertBusy(() -> {
             GetMappingsResponse mappingsResponse = client().admin().indices().prepareGetMappings().get();
@@ -154,7 +154,7 @@ public void testBulkWithGlobalDefaults() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk-missing-index-type.json");
         {
             BulkRequestBuilder bulkBuilder = client().prepareBulk();
-            bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+            bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
             ActionRequestValidationException ex = expectThrows(ActionRequestValidationException.class, bulkBuilder::get);
 
             assertThat(ex.validationErrors(), containsInAnyOrder("index is missing", "index is missing", "index is missing"));
@@ -164,7 +164,7 @@ public void testBulkWithGlobalDefaults() throws Exception {
             createSamplePipeline("pipeline");
             BulkRequestBuilder bulkBuilder = client().prepareBulk("test").routing("routing").pipeline("pipeline");
 
-            bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+            bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
             BulkResponse bulkItemResponses = bulkBuilder.get();
             assertFalse(bulkItemResponses.hasFailures());
         }
@@ -182,7 +182,7 @@ private void createSamplePipeline(String pipelineId) throws IOException, Executi
 
         AcknowledgedResponse acknowledgedResponse = client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest(pipelineId, BytesReference.bytes(pipeline), XContentType.JSON))
+            .putPipeline(new PutPipelineRequest(pipelineId, BytesReference.bytes(pipeline), MediaTypeRegistry.JSON))
             .get();
 
         assertTrue(acknowledgedResponse.isAcknowledged());
@@ -193,34 +193,63 @@ public void testDeleteIndexWhileIndexing() throws Exception {
         String index = "deleted_while_indexing";
         createIndex(index);
         AtomicBoolean stopped = new AtomicBoolean();
-        Thread[] threads = new Thread[between(1, 4)];
         AtomicInteger docID = new AtomicInteger();
-        for (int i = 0; i < threads.length; i++) {
-            threads[i] = new Thread(() -> {
-                while (stopped.get() == false && docID.get() < 5000) {
-                    String id = Integer.toString(docID.incrementAndGet());
-                    try {
-                        IndexResponse response = client().prepareIndex(index)
-                            .setId(id)
-                            .setSource(Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()), XContentType.JSON)
-                            .get();
-                        assertThat(response.getResult(), is(oneOf(CREATED, UPDATED)));
-                        logger.info("--> index id={} seq_no={}", response.getId(), response.getSeqNo());
-                    } catch (OpenSearchException ignore) {
-                        logger.info("--> fail to index id={}", id);
-                    }
+        Thread thread = new Thread(() -> {
+            while (stopped.get() == false && docID.get() < 5000) {
+                String id = Integer.toString(docID.incrementAndGet());
+                try {
+                    IndexResponse response = client().prepareIndex(index)
+                        .setId(id)
+                        .setSource(Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()), MediaTypeRegistry.JSON)
+                        .get();
+                    assertThat(response.getResult(), is(oneOf(CREATED, UPDATED)));
+                    logger.info("--> index id={} seq_no={}", response.getId(), response.getSeqNo());
+                } catch (OpenSearchException ignore) {
+                    logger.info("--> fail to index id={}", id);
                 }
-            });
-            threads[i].start();
-        }
+            }
+        });
+        thread.start();
         ensureGreen(index);
         assertBusy(() -> assertThat(docID.get(), greaterThanOrEqualTo(1)));
         assertAcked(client().admin().indices().prepareDelete(index));
         stopped.set(true);
-        for (Thread thread : threads) {
-            thread.join(ReplicationRequest.DEFAULT_TIMEOUT.millis() / 2);
-            assertFalse(thread.isAlive());
-        }
+        thread.join(ReplicationRequest.DEFAULT_TIMEOUT.millis() / 2);
+        assertFalse(thread.isAlive());
     }
 
+    public void testDocIdTooLong() {
+        String index = "testing";
+        createIndex(index);
+        String validId = String.join("", Collections.nCopies(512, "a"));
+        String invalidId = String.join("", Collections.nCopies(513, "a"));
+
+        // Index Request
+        IndexRequest indexRequest = new IndexRequest(index).source(Collections.singletonMap("foo", "baz"));
+        // Valid id shouldn't throw any exception
+        assertFalse(client().prepareBulk().add(indexRequest.id(validId)).get().hasFailures());
+        // Invalid id should throw the ActionRequestValidationException
+        validateDocIdLimit(() -> client().prepareBulk().add(indexRequest.id(invalidId)).get());
+
+        // Update Request
+        UpdateRequest updateRequest = new UpdateRequest(index, validId).doc("reason", "no source");
+        // Valid id shouldn't throw any exception
+        assertFalse(client().prepareBulk().add(updateRequest).get().hasFailures());
+        // Invalid id should throw the ActionRequestValidationException
+        validateDocIdLimit(() -> client().prepareBulk().add(updateRequest.id(invalidId)).get());
+    }
+
+    private void validateDocIdLimit(Runnable runner) {
+        try {
+            runner.run();
+            fail("Request validation for docId didn't fail");
+        } catch (ActionRequestValidationException e) {
+            assertEquals(
+                1,
+                e.validationErrors().stream().filter(msg -> msg.contains("is too long, must be no longer than 512 bytes but was")).count()
+            );
+        } catch (Exception e) {
+            fail("Request validation for docId failed with different exception: " + e);
+        }
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorClusterSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorClusterSettingsIT.java
index 14531787e9903..ea7af48266905 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorClusterSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorClusterSettingsIT.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
@@ -50,9 +50,9 @@ public void testBulkProcessorAutoCreateRestrictions() throws Exception {
         client().admin().cluster().prepareHealth("willwork").setWaitForGreenStatus().execute().actionGet();
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("willwork").setId("1").setSource("{\"foo\":1}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("wontwork").setId("2").setSource("{\"foo\":2}", XContentType.JSON));
-        bulkRequestBuilder.add(client().prepareIndex("willwork").setId("3").setSource("{\"foo\":3}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("willwork").setId("1").setSource("{\"foo\":1}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("wontwork").setId("2").setSource("{\"foo\":2}", MediaTypeRegistry.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("willwork").setId("3").setSource("{\"foo\":3}", MediaTypeRegistry.JSON));
         BulkResponse br = bulkRequestBuilder.get();
         BulkItemResponse[] responses = br.getItems();
         assertEquals(3, responses.length);
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorIT.java
index 850034bc631b1..94202c208ba3d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorIT.java
@@ -33,6 +33,7 @@
 package org.opensearch.action.bulk;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.action.get.MultiGetItemResponse;
 import org.opensearch.action.get.MultiGetRequestBuilder;
 import org.opensearch.action.get.MultiGetResponse;
@@ -41,9 +42,9 @@
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Arrays;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorRetryIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorRetryIT.java
index 687a4e9b733fd..737c0acc309fd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorRetryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkProcessorRetryIT.java
@@ -32,12 +32,11 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
-
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.transport.RemoteTransportException;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkRejectionIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkRejectionIT.java
index aa2f2a214de27..a41664fe71c24 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkRejectionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkRejectionIT.java
@@ -31,15 +31,15 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.WriteRequest;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.IndexService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkWithUpdatesIT.java b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkWithUpdatesIT.java
index 6311ac6876192..d7fb632c847d1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkWithUpdatesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/bulk/BulkWithUpdatesIT.java
@@ -46,9 +46,9 @@
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.VersionType;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.plugins.Plugin;
@@ -56,8 +56,8 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptException;
 import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -105,18 +105,9 @@ protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
 
             scripts.put("ctx._source.field2 = 'value2'", vars -> srcScript(vars, source -> source.replace("field2", "value2")));
 
-            scripts.put(
-                "throw script exception on unknown var",
-                vars -> {
-                    throw new ScriptException(
-                        "message",
-                        null,
-                        Collections.emptyList(),
-                        "exception on unknown var",
-                        CustomScriptPlugin.NAME
-                    );
-                }
-            );
+            scripts.put("throw script exception on unknown var", vars -> {
+                throw new ScriptException("message", null, Collections.emptyList(), "exception on unknown var", CustomScriptPlugin.NAME);
+            });
 
             scripts.put("ctx.op = \"none\"", vars -> ((Map<String, Object>) vars.get("ctx")).put("op", "none"));
             scripts.put("ctx.op = \"delete\"", vars -> ((Map<String, Object>) vars.get("ctx")).put("op", "delete"));
@@ -627,19 +618,19 @@ public void testThatInvalidIndexNamesShouldNotBreakCompleteBulkRequest() {
     // issue 6630
     public void testThatFailedUpdateRequestReturnsCorrectType() throws Exception {
         BulkResponse indexBulkItemResponse = client().prepareBulk()
-            .add(new IndexRequest("test").id("3").source("{ \"title\" : \"Great Title of doc 3\" }", XContentType.JSON))
-            .add(new IndexRequest("test").id("4").source("{ \"title\" : \"Great Title of doc 4\" }", XContentType.JSON))
-            .add(new IndexRequest("test").id("5").source("{ \"title\" : \"Great Title of doc 5\" }", XContentType.JSON))
-            .add(new IndexRequest("test").id("6").source("{ \"title\" : \"Great Title of doc 6\" }", XContentType.JSON))
+            .add(new IndexRequest("test").id("3").source("{ \"title\" : \"Great Title of doc 3\" }", MediaTypeRegistry.JSON))
+            .add(new IndexRequest("test").id("4").source("{ \"title\" : \"Great Title of doc 4\" }", MediaTypeRegistry.JSON))
+            .add(new IndexRequest("test").id("5").source("{ \"title\" : \"Great Title of doc 5\" }", MediaTypeRegistry.JSON))
+            .add(new IndexRequest("test").id("6").source("{ \"title\" : \"Great Title of doc 6\" }", MediaTypeRegistry.JSON))
             .setRefreshPolicy(RefreshPolicy.IMMEDIATE)
             .get();
         assertNoFailures(indexBulkItemResponse);
 
         BulkResponse bulkItemResponse = client().prepareBulk()
-            .add(new IndexRequest("test").id("1").source("{ \"title\" : \"Great Title of doc 1\" }", XContentType.JSON))
-            .add(new IndexRequest("test").id("2").source("{ \"title\" : \"Great Title of doc 2\" }", XContentType.JSON))
-            .add(new UpdateRequest("test", "3").doc("{ \"date\" : \"2014-01-30T23:59:57\"}", XContentType.JSON))
-            .add(new UpdateRequest("test", "4").doc("{ \"date\" : \"2014-13-30T23:59:57\"}", XContentType.JSON))
+            .add(new IndexRequest("test").id("1").source("{ \"title\" : \"Great Title of doc 1\" }", MediaTypeRegistry.JSON))
+            .add(new IndexRequest("test").id("2").source("{ \"title\" : \"Great Title of doc 2\" }", MediaTypeRegistry.JSON))
+            .add(new UpdateRequest("test", "3").doc("{ \"date\" : \"2014-01-30T23:59:57\"}", MediaTypeRegistry.JSON))
+            .add(new UpdateRequest("test", "4").doc("{ \"date\" : \"2014-13-30T23:59:57\"}", MediaTypeRegistry.JSON))
             .add(new DeleteRequest("test", "5"))
             .add(new DeleteRequest("test", "6"))
             .get();
@@ -741,13 +732,21 @@ public void testNoopUpdate() {
 
         final BulkItemResponse noopUpdate = bulkResponse.getItems()[0];
         assertThat(noopUpdate.getResponse().getResult(), equalTo(DocWriteResponse.Result.NOOP));
-        assertThat(Strings.toString(noopUpdate), noopUpdate.getResponse().getShardInfo().getSuccessful(), equalTo(2));
+        assertThat(
+            Strings.toString(MediaTypeRegistry.JSON, noopUpdate),
+            noopUpdate.getResponse().getShardInfo().getSuccessful(),
+            equalTo(2)
+        );
 
         final BulkItemResponse notFoundUpdate = bulkResponse.getItems()[1];
         assertNotNull(notFoundUpdate.getFailure());
 
         final BulkItemResponse notFoundDelete = bulkResponse.getItems()[2];
         assertThat(notFoundDelete.getResponse().getResult(), equalTo(DocWriteResponse.Result.NOT_FOUND));
-        assertThat(Strings.toString(notFoundDelete), notFoundDelete.getResponse().getShardInfo().getSuccessful(), equalTo(2));
+        assertThat(
+            Strings.toString(MediaTypeRegistry.JSON, notFoundDelete),
+            notFoundDelete.getResponse().getShardInfo().getSuccessful(),
+            equalTo(2)
+        );
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/ingest/AsyncIngestProcessorIT.java b/server/src/internalClusterTest/java/org/opensearch/action/ingest/AsyncIngestProcessorIT.java
index a4111e14f06a1..c62c61d5919d6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/ingest/AsyncIngestProcessorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/ingest/AsyncIngestProcessorIT.java
@@ -39,11 +39,11 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.ingest.AbstractProcessor;
@@ -84,12 +84,12 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     public void testAsyncProcessorImplementation() {
         // A pipeline with 2 processors: the test async processor and sync test processor.
         BytesReference pipelineBody = new BytesArray("{\"processors\": [{\"test-async\": {}, \"test\": {}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("_id", pipelineBody, XContentType.JSON)).actionGet();
+        client().admin().cluster().putPipeline(new PutPipelineRequest("_id", pipelineBody, MediaTypeRegistry.JSON)).actionGet();
 
         BulkRequest bulkRequest = new BulkRequest();
         int numDocs = randomIntBetween(8, 256);
         for (int i = 0; i < numDocs; i++) {
-            bulkRequest.add(new IndexRequest("foobar").id(Integer.toString(i)).source("{}", XContentType.JSON).setPipeline("_id"));
+            bulkRequest.add(new IndexRequest("foobar").id(Integer.toString(i)).source("{}", MediaTypeRegistry.JSON).setPipeline("_id"));
         }
         BulkResponse bulkResponse = client().bulk(bulkRequest).actionGet();
         assertThat(bulkResponse.getItems().length, equalTo(numDocs));
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/search/SearchProgressActionListenerIT.java b/server/src/internalClusterTest/java/org/opensearch/action/search/SearchProgressActionListenerIT.java
index eb69eaaa9c2e1..4475ee837da4e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/search/SearchProgressActionListenerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/search/SearchProgressActionListenerIT.java
@@ -34,9 +34,9 @@
 
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
-
 import org.opensearch.client.Client;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.aggregations.AggregationBuilders;
@@ -44,7 +44,6 @@
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/search/TransportSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/action/search/TransportSearchIT.java
index a356d273f7060..f0a3b5a5901ce 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/search/TransportSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/search/TransportSearchIT.java
@@ -35,9 +35,7 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.CollectionTerminatedException;
 import org.apache.lucene.search.ScoreMode;
-
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -47,23 +45,25 @@
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.RangeQueryBuilder;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
@@ -370,6 +370,48 @@ public void testSearchIdle() throws Exception {
         });
     }
 
+    public void testSearchIdleWithSegmentReplication() {
+        int numOfReplicas = 1;
+        internalCluster().ensureAtLeastNumDataNodes(numOfReplicas + 1);
+        final Settings.Builder settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, randomIntBetween(1, 5))
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numOfReplicas)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+        assertAcked(prepareCreate("test").setSettings(settings).setMapping("created_date", "type=date,format=yyyy-MM-dd"));
+        ensureGreen("test");
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(
+                    Settings.builder()
+                        .put(IndexSettings.INDEX_SEARCH_IDLE_AFTER.getKey(), TimeValue.timeValueMillis(randomIntBetween(50, 500)))
+                )
+        );
+
+        for (String node : internalCluster().nodesInclude("test")) {
+            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, node);
+            for (IndexShard indexShard : indicesService.indexServiceSafe(resolveIndex("test"))) {
+                assertFalse(indexShard.isSearchIdleSupported());
+            }
+        }
+
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0))
+        );
+
+        for (String node : internalCluster().nodesInclude("test")) {
+            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, node);
+            for (IndexShard indexShard : indicesService.indexServiceSafe(resolveIndex("test"))) {
+                assertTrue(indexShard.isSearchIdleSupported());
+            }
+        }
+        ;
+    }
+
     public void testCircuitBreakerReduceFail() throws Exception {
         int numShards = randomIntBetween(1, 10);
         indexSomeDocs("test", numShards, numShards * 3);
@@ -552,6 +594,11 @@ protected Aggregator createInternal(
                 ) throws IOException {
                     return new TestAggregator(name, parent, searchContext);
                 }
+
+                @Override
+                protected boolean supportsConcurrentSegmentSearch() {
+                    return true;
+                }
             };
         }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/support/ActiveShardsObserverIT.java b/server/src/internalClusterTest/java/org/opensearch/action/support/ActiveShardsObserverIT.java
index 30f5c21ba6cd7..e19a7483370c2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/support/ActiveShardsObserverIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/support/ActiveShardsObserverIT.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/support/WaitActiveShardCountIT.java b/server/src/internalClusterTest/java/org/opensearch/action/support/WaitActiveShardCountIT.java
index e919b2b85e079..08cffac8aac5d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/support/WaitActiveShardCountIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/support/WaitActiveShardCountIT.java
@@ -35,12 +35,11 @@
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
-
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
@@ -63,11 +62,11 @@ public void testReplicationWaitsForActiveShardCount() throws Exception {
         assertAcked(createIndexResponse);
 
         // indexing, by default, will work (waiting for one shard copy only)
-        client().prepareIndex("test").setId("1").setSource(source("1", "test"), XContentType.JSON).execute().actionGet();
+        client().prepareIndex("test").setId("1").setSource(source("1", "test"), MediaTypeRegistry.JSON).execute().actionGet();
         try {
             client().prepareIndex("test")
                 .setId("1")
-                .setSource(source("1", "test"), XContentType.JSON)
+                .setSource(source("1", "test"), MediaTypeRegistry.JSON)
                 .setWaitForActiveShards(2) // wait for 2 active shard copies
                 .setTimeout(timeValueMillis(100))
                 .execute()
@@ -99,7 +98,7 @@ public void testReplicationWaitsForActiveShardCount() throws Exception {
         // this should work, since we now have two
         client().prepareIndex("test")
             .setId("1")
-            .setSource(source("1", "test"), XContentType.JSON)
+            .setSource(source("1", "test"), MediaTypeRegistry.JSON)
             .setWaitForActiveShards(2)
             .setTimeout(timeValueSeconds(1))
             .execute()
@@ -108,7 +107,7 @@ public void testReplicationWaitsForActiveShardCount() throws Exception {
         try {
             client().prepareIndex("test")
                 .setId("1")
-                .setSource(source("1", "test"), XContentType.JSON)
+                .setSource(source("1", "test"), MediaTypeRegistry.JSON)
                 .setWaitForActiveShards(ActiveShardCount.ALL)
                 .setTimeout(timeValueMillis(100))
                 .execute()
@@ -143,7 +142,7 @@ public void testReplicationWaitsForActiveShardCount() throws Exception {
         // this should work, since we now have all shards started
         client().prepareIndex("test")
             .setId("1")
-            .setSource(source("1", "test"), XContentType.JSON)
+            .setSource(source("1", "test"), MediaTypeRegistry.JSON)
             .setWaitForActiveShards(ActiveShardCount.ALL)
             .setTimeout(timeValueSeconds(1))
             .execute()
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/support/clustermanager/IndexingClusterManagerFailoverIT.java b/server/src/internalClusterTest/java/org/opensearch/action/support/clustermanager/IndexingClusterManagerFailoverIT.java
new file mode 100644
index 0000000000000..959b16d4c4694
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/action/support/clustermanager/IndexingClusterManagerFailoverIT.java
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.action.DocWriteResponse;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CyclicBarrier;
+
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class IndexingClusterManagerFailoverIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        final HashSet<Class<? extends Plugin>> classes = new HashSet<>(super.nodePlugins());
+        classes.add(MockTransportService.TestPlugin.class);
+        return classes;
+    }
+
+    /**
+     * Indexing operations which entail mapping changes require a blocking request to the cluster-manager node to update the mapping.
+     * If the cluster-manager node is being disrupted or if it cannot commit cluster state changes, it needs to retry within timeout limits.
+     * This retry logic is implemented in TransportMasterNodeAction and tested by the following cluster-manager failover scenario.
+     */
+    public void testClusterManagerFailoverDuringIndexingWithMappingChanges() throws Throwable {
+        logger.info("--> start 4 nodes, 3 cluster-manager, 1 data");
+
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
+
+        internalCluster().startClusterManagerOnlyNodes(3, Settings.EMPTY);
+
+        String dataNode = internalCluster().startDataOnlyNode(Settings.EMPTY);
+
+        logger.info("--> wait for all nodes to join the cluster");
+        ensureStableCluster(4);
+
+        // We index data with mapping changes into cluster and have cluster-manager failover at same time
+        client().admin()
+            .indices()
+            .prepareCreate("myindex")
+            .setSettings(Settings.builder().put("index.number_of_shards", 1).put("index.number_of_replicas", 0))
+            .get();
+        ensureGreen("myindex");
+
+        final CyclicBarrier barrier = new CyclicBarrier(2);
+
+        Thread indexingThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    barrier.await();
+                } catch (InterruptedException e) {
+                    logger.warn("Barrier interrupted", e);
+                    return;
+                } catch (BrokenBarrierException e) {
+                    logger.warn("Broken barrier", e);
+                    return;
+                }
+                for (int i = 0; i < 10; i++) {
+                    // index data
+                    IndexResponse response = client(dataNode).prepareIndex("myindex").setSource("field_" + i, "val").get();
+                    assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
+                }
+            }
+        });
+        indexingThread.setName("indexingThread");
+        indexingThread.start();
+
+        barrier.await();
+
+        // interrupt communication between cluster-manager and other nodes in cluster
+        NetworkDisruption partition = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
+        internalCluster().setDisruptionScheme(partition);
+
+        logger.info("--> disrupting network");
+        partition.startDisrupting();
+
+        logger.info("--> waiting for new cluster-manager to be elected");
+        ensureStableCluster(3, dataNode);
+
+        partition.stopDisrupting();
+        logger.info("--> waiting to heal");
+        ensureStableCluster(4);
+
+        indexingThread.join();
+
+        ensureGreen("myindex");
+        refresh();
+        assertThat(client().prepareSearch("myindex").get().getHits().getTotalHits().value, equalTo(10L));
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/support/master/IndexingMasterFailoverIT.java b/server/src/internalClusterTest/java/org/opensearch/action/support/master/IndexingMasterFailoverIT.java
deleted file mode 100644
index f8db63bc8b61d..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/action/support/master/IndexingMasterFailoverIT.java
+++ /dev/null
@@ -1,132 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.support.master;
-
-import org.opensearch.action.DocWriteResponse;
-import org.opensearch.action.index.IndexResponse;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.disruption.NetworkDisruption;
-import org.opensearch.test.transport.MockTransportService;
-
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.concurrent.BrokenBarrierException;
-import java.util.concurrent.CyclicBarrier;
-
-import static org.hamcrest.Matchers.equalTo;
-
-@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
-public class IndexingMasterFailoverIT extends OpenSearchIntegTestCase {
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        final HashSet<Class<? extends Plugin>> classes = new HashSet<>(super.nodePlugins());
-        classes.add(MockTransportService.TestPlugin.class);
-        return classes;
-    }
-
-    /**
-     * Indexing operations which entail mapping changes require a blocking request to the master node to update the mapping.
-     * If the master node is being disrupted or if it cannot commit cluster state changes, it needs to retry within timeout limits.
-     * This retry logic is implemented in TransportMasterNodeAction and tested by the following master failover scenario.
-     */
-    public void testMasterFailoverDuringIndexingWithMappingChanges() throws Throwable {
-        logger.info("--> start 4 nodes, 3 master, 1 data");
-
-        internalCluster().setBootstrapMasterNodeIndex(2);
-
-        internalCluster().startMasterOnlyNodes(3, Settings.EMPTY);
-
-        String dataNode = internalCluster().startDataOnlyNode(Settings.EMPTY);
-
-        logger.info("--> wait for all nodes to join the cluster");
-        ensureStableCluster(4);
-
-        // We index data with mapping changes into cluster and have master failover at same time
-        client().admin()
-            .indices()
-            .prepareCreate("myindex")
-            .setSettings(Settings.builder().put("index.number_of_shards", 1).put("index.number_of_replicas", 0))
-            .get();
-        ensureGreen("myindex");
-
-        final CyclicBarrier barrier = new CyclicBarrier(2);
-
-        Thread indexingThread = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    barrier.await();
-                } catch (InterruptedException e) {
-                    logger.warn("Barrier interrupted", e);
-                    return;
-                } catch (BrokenBarrierException e) {
-                    logger.warn("Broken barrier", e);
-                    return;
-                }
-                for (int i = 0; i < 10; i++) {
-                    // index data
-                    IndexResponse response = client(dataNode).prepareIndex("myindex").setSource("field_" + i, "val").get();
-                    assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
-                }
-            }
-        });
-        indexingThread.setName("indexingThread");
-        indexingThread.start();
-
-        barrier.await();
-
-        // interrupt communication between master and other nodes in cluster
-        NetworkDisruption partition = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
-        internalCluster().setDisruptionScheme(partition);
-
-        logger.info("--> disrupting network");
-        partition.startDisrupting();
-
-        logger.info("--> waiting for new master to be elected");
-        ensureStableCluster(3, dataNode);
-
-        partition.stopDisrupting();
-        logger.info("--> waiting to heal");
-        ensureStableCluster(4);
-
-        indexingThread.join();
-
-        ensureGreen("myindex");
-        refresh();
-        assertThat(client().prepareSearch("myindex").get().getHits().getTotalHits().value, equalTo(10L));
-    }
-
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/support/replication/TransportReplicationActionRetryOnClosedNodeIT.java b/server/src/internalClusterTest/java/org/opensearch/action/support/replication/TransportReplicationActionRetryOnClosedNodeIT.java
index 8a9f3eb5f2e63..569e64d795b06 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/support/replication/TransportReplicationActionRetryOnClosedNodeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/support/replication/TransportReplicationActionRetryOnClosedNodeIT.java
@@ -32,38 +32,37 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.PluginsService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
-
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -203,7 +202,7 @@ public <T extends TransportResponse> void sendRequest(
     }
 
     public void testRetryOnStoppedTransportService() throws Exception {
-        internalCluster().startMasterOnlyNodes(2);
+        internalCluster().startClusterManagerOnlyNodes(2);
         String primary = internalCluster().startDataOnlyNode();
         assertAcked(
             prepareCreate("test").setSettings(
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/termvectors/GetTermVectorsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/termvectors/GetTermVectorsIT.java
index b5e60f44983f5..7bd1467933e00 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/termvectors/GetTermVectorsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/termvectors/GetTermVectorsIT.java
@@ -39,15 +39,15 @@
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.MockKeywordPlugin;
@@ -74,6 +74,10 @@
 
 public class GetTermVectorsIT extends AbstractTermVectorsTestCase {
 
+    public GetTermVectorsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(MockKeywordPlugin.class);
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/termvectors/MultiTermVectorsIT.java b/server/src/internalClusterTest/java/org/opensearch/action/termvectors/MultiTermVectorsIT.java
index 91d280a9c4771..7c6c47c682281 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/termvectors/MultiTermVectorsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/termvectors/MultiTermVectorsIT.java
@@ -52,6 +52,10 @@
 import static org.hamcrest.Matchers.nullValue;
 
 public class MultiTermVectorsIT extends AbstractTermVectorsTestCase {
+    public MultiTermVectorsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     public void testDuelESLucene() throws Exception {
         AbstractTermVectorsTestCase.TestFieldSetting[] testFieldSettings = getFieldSettings();
         createIndexBasedOnFieldSettings("test", "alias", testFieldSettings);
diff --git a/server/src/internalClusterTest/java/org/opensearch/aliases/IndexAliasesIT.java b/server/src/internalClusterTest/java/org/opensearch/aliases/IndexAliasesIT.java
index ff64a2cd90cb8..f91df19232971 100644
--- a/server/src/internalClusterTest/java/org/opensearch/aliases/IndexAliasesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/aliases/IndexAliasesIT.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.aliases;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistResponse;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.delete.DeleteResponse;
@@ -52,7 +50,7 @@
 import org.opensearch.common.StopWatch;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.TermQueryBuilder;
@@ -88,7 +86,6 @@
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_READ_ONLY;
 import static org.opensearch.index.query.QueryBuilders.rangeQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
-import static org.opensearch.test.hamcrest.CollectionAssertions.hasKey;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertBlocked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -97,6 +94,7 @@
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.emptyArray;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
@@ -117,7 +115,7 @@ public void testAliases() throws Exception {
         logger.info("--> indexing against [alias1], should fail now");
         IllegalArgumentException exception = expectThrows(
             IllegalArgumentException.class,
-            () -> client().index(indexRequest("alias1").id("1").source(source("2", "test"), XContentType.JSON)).actionGet()
+            () -> client().index(indexRequest("alias1").id("1").source(source("2", "test"), MediaTypeRegistry.JSON)).actionGet()
         );
         assertThat(
             exception.getMessage(),
@@ -134,7 +132,7 @@ public void testAliases() throws Exception {
         });
 
         logger.info("--> indexing against [alias1], should work now");
-        IndexResponse indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), XContentType.JSON))
+        IndexResponse indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), MediaTypeRegistry.JSON))
             .actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test"));
 
@@ -151,7 +149,7 @@ public void testAliases() throws Exception {
         logger.info("--> indexing against [alias1], should fail now");
         exception = expectThrows(
             IllegalArgumentException.class,
-            () -> client().index(indexRequest("alias1").id("1").source(source("2", "test"), XContentType.JSON)).actionGet()
+            () -> client().index(indexRequest("alias1").id("1").source(source("2", "test"), MediaTypeRegistry.JSON)).actionGet()
         );
         assertThat(
             exception.getMessage(),
@@ -179,7 +177,7 @@ public void testAliases() throws Exception {
         });
 
         logger.info("--> indexing against [alias1], should work now");
-        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
+        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test"));
 
         assertAliasesVersionIncreases("test_x", () -> {
@@ -188,7 +186,7 @@ public void testAliases() throws Exception {
         });
 
         logger.info("--> indexing against [alias1], should work now");
-        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
+        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test_x"));
 
         logger.info("--> deleting against [alias1], should fail now");
@@ -201,7 +199,7 @@ public void testAliases() throws Exception {
         });
 
         logger.info("--> indexing against [alias1], should work against [test_x]");
-        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
+        indexResponse = client().index(indexRequest("alias1").id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test_x"));
     }
 
@@ -283,16 +281,18 @@ public void testSearchingFilteringAliasesSingleIndex() throws Exception {
 
         logger.info("--> indexing against [test]");
         client().index(
-            indexRequest("test").id("1").source(source("1", "foo test"), XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
+            indexRequest("test").id("1").source(source("1", "foo test"), MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
         ).actionGet();
         client().index(
-            indexRequest("test").id("2").source(source("2", "bar test"), XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
+            indexRequest("test").id("2").source(source("2", "bar test"), MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
         ).actionGet();
         client().index(
-            indexRequest("test").id("3").source(source("3", "baz test"), XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
+            indexRequest("test").id("3").source(source("3", "baz test"), MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
         ).actionGet();
         client().index(
-            indexRequest("test").id("4").source(source("4", "something else"), XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE)
+            indexRequest("test").id("4")
+                .source(source("4", "something else"), MediaTypeRegistry.JSON)
+                .setRefreshPolicy(RefreshPolicy.IMMEDIATE)
         ).actionGet();
 
         logger.info("--> checking single filtering alias search");
@@ -389,16 +389,16 @@ public void testSearchingFilteringAliasesTwoIndices() throws Exception {
         );
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").id("1").source(source("1", "foo test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("2").source(source("2", "bar test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("3").source(source("3", "baz test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("4").source(source("4", "something else"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").id("1").source(source("1", "foo test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("2").source(source("2", "bar test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("3").source(source("3", "baz test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("4").source(source("4", "something else"), MediaTypeRegistry.JSON)).get();
 
         logger.info("--> indexing against [test2]");
-        client().index(indexRequest("test2").id("5").source(source("5", "foo test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("6").source(source("6", "bar test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("7").source(source("7", "baz test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("8").source(source("8", "something else"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").id("5").source(source("5", "foo test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("6").source(source("6", "bar test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("7").source(source("7", "baz test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("8").source(source("8", "something else"), MediaTypeRegistry.JSON)).get();
 
         refresh();
 
@@ -503,17 +503,17 @@ public void testSearchingFilteringAliasesMultipleIndices() throws Exception {
         );
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").id("11").source(source("11", "foo test1"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("12").source(source("12", "bar test1"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("13").source(source("13", "baz test1"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").id("11").source(source("11", "foo test1"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("12").source(source("12", "bar test1"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("13").source(source("13", "baz test1"), MediaTypeRegistry.JSON)).get();
 
-        client().index(indexRequest("test2").id("21").source(source("21", "foo test2"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("22").source(source("22", "bar test2"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("23").source(source("23", "baz test2"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").id("21").source(source("21", "foo test2"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("22").source(source("22", "bar test2"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("23").source(source("23", "baz test2"), MediaTypeRegistry.JSON)).get();
 
-        client().index(indexRequest("test3").id("31").source(source("31", "foo test3"), XContentType.JSON)).get();
-        client().index(indexRequest("test3").id("32").source(source("32", "bar test3"), XContentType.JSON)).get();
-        client().index(indexRequest("test3").id("33").source(source("33", "baz test3"), XContentType.JSON)).get();
+        client().index(indexRequest("test3").id("31").source(source("31", "foo test3"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test3").id("32").source(source("32", "bar test3"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test3").id("33").source(source("33", "baz test3"), MediaTypeRegistry.JSON)).get();
 
         refresh();
 
@@ -626,16 +626,16 @@ public void testDeletingByQueryFilteringAliases() throws Exception {
         );
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").id("1").source(source("1", "foo test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("2").source(source("2", "bar test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("3").source(source("3", "baz test"), XContentType.JSON)).get();
-        client().index(indexRequest("test1").id("4").source(source("4", "something else"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").id("1").source(source("1", "foo test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("2").source(source("2", "bar test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("3").source(source("3", "baz test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test1").id("4").source(source("4", "something else"), MediaTypeRegistry.JSON)).get();
 
         logger.info("--> indexing against [test2]");
-        client().index(indexRequest("test2").id("5").source(source("5", "foo test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("6").source(source("6", "bar test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("7").source(source("7", "baz test"), XContentType.JSON)).get();
-        client().index(indexRequest("test2").id("8").source(source("8", "something else"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").id("5").source(source("5", "foo test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("6").source(source("6", "bar test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("7").source(source("7", "baz test"), MediaTypeRegistry.JSON)).get();
+        client().index(indexRequest("test2").id("8").source(source("8", "something else"), MediaTypeRegistry.JSON)).get();
 
         refresh();
 
@@ -684,8 +684,9 @@ public void testDeleteAliases() throws Exception {
 
         assertAliasesVersionIncreases(indices, () -> admin().indices().prepareAliases().removeAlias(indices, aliases).get());
 
-        AliasesExistResponse response = admin().indices().prepareAliasesExist(aliases).get();
-        assertThat(response.exists(), equalTo(false));
+        for (String alias : aliases) {
+            assertTrue(admin().indices().prepareGetAliases(alias).get().getAliases().isEmpty());
+        }
 
         logger.info("--> creating index [foo_foo] and [bar_bar]");
         assertAcked(prepareCreate("foo_foo"));
@@ -701,9 +702,9 @@ public void testDeleteAliases() throws Exception {
             () -> assertAcked(admin().indices().prepareAliases().addAliasAction(AliasActions.remove().index("foo*").alias("foo")))
         );
 
-        assertTrue(admin().indices().prepareAliasesExist("foo").get().exists());
-        assertFalse(admin().indices().prepareAliasesExist("foo").setIndices("foo_foo").get().exists());
-        assertTrue(admin().indices().prepareAliasesExist("foo").setIndices("bar_bar").get().exists());
+        assertFalse(admin().indices().prepareGetAliases("foo").get().getAliases().isEmpty());
+        assertTrue(admin().indices().prepareGetAliases("foo").setIndices("foo_foo").get().getAliases().isEmpty());
+        assertFalse(admin().indices().prepareGetAliases("foo").setIndices("bar_bar").get().getAliases().isEmpty());
         IllegalArgumentException iae = expectThrows(
             IllegalArgumentException.class,
             () -> admin().indices().prepareAliases().addAliasAction(AliasActions.remove().index("foo").alias("foo")).execute().actionGet()
@@ -723,7 +724,7 @@ public void testWaitForAliasCreationMultipleShards() throws Exception {
         for (int i = 0; i < 10; i++) {
             final String aliasName = "alias" + i;
             assertAliasesVersionIncreases("test", () -> assertAcked(admin().indices().prepareAliases().addAlias("test", aliasName)));
-            client().index(indexRequest(aliasName).id("1").source(source("1", "test"), XContentType.JSON)).get();
+            client().index(indexRequest(aliasName).id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).get();
         }
     }
 
@@ -744,7 +745,7 @@ public void testWaitForAliasCreationSingleShard() throws Exception {
         for (int i = 0; i < 10; i++) {
             final String aliasName = "alias" + i;
             assertAliasesVersionIncreases("test", () -> assertAcked(admin().indices().prepareAliases().addAlias("test", aliasName)));
-            client().index(indexRequest(aliasName).id("1").source(source("1", "test"), XContentType.JSON)).get();
+            client().index(indexRequest(aliasName).id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).get();
         }
     }
 
@@ -766,7 +767,7 @@ public void run() {
                         "test",
                         () -> assertAcked(admin().indices().prepareAliases().addAlias("test", aliasName))
                     );
-                    client().index(indexRequest(aliasName).id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
+                    client().index(indexRequest(aliasName).id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).actionGet();
                 }
             });
         }
@@ -880,8 +881,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(0).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getSearchRouting(), nullValue());
-        AliasesExistResponse existsResponse = admin().indices().prepareAliasesExist("alias1").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("alias1").get().getAliases().isEmpty());
 
         logger.info("--> getting all aliases that start with alias*");
         getResponse = admin().indices().prepareGetAliases("alias*").get();
@@ -898,8 +898,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(1).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(1).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(1).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("alias*").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("alias*").get().getAliases().isEmpty());
 
         logger.info("--> creating aliases [bar, baz, foo]");
         assertAliasesVersionIncreases(
@@ -937,8 +936,10 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("bazbar").get(1).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("bazbar").get(1).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("bazbar").get(1).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("bar", "bac").addIndices("bazbar").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("bar").get().getAliases().isEmpty());
+        assertFalse(admin().indices().prepareGetAliases("bac").get().getAliases().isEmpty());
+        assertFalse(admin().indices().prepareGetAliases("bar").addIndices("bazbar").get().getAliases().isEmpty());
+        assertFalse(admin().indices().prepareGetAliases("bac").addIndices("bazbar").get().getAliases().isEmpty());
 
         logger.info("--> getting *b* for index baz*");
         getResponse = admin().indices().prepareGetAliases("*b*").addIndices("baz*").get();
@@ -957,8 +958,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("bazbar").get(1).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("bazbar").get(1).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("bazbar").get(1).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("*b*").addIndices("baz*").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("*b*").addIndices("baz*").get().getAliases().isEmpty());
 
         logger.info("--> getting *b* for index *bar");
         getResponse = admin().indices().prepareGetAliases("b*").addIndices("*bar").get();
@@ -982,8 +982,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(0).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getIndexRouting(), equalTo("bla"));
         assertThat(getResponse.getAliases().get("foobar").get(0).getSearchRouting(), equalTo("bla"));
-        existsResponse = admin().indices().prepareAliasesExist("b*").addIndices("*bar").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("b*").addIndices("*bar").get().getAliases().isEmpty());
 
         logger.info("--> getting f* for index *bar");
         getResponse = admin().indices().prepareGetAliases("f*").addIndices("*bar").get();
@@ -994,8 +993,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(0).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("f*").addIndices("*bar").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("f*").addIndices("*bar").get().getAliases().isEmpty());
 
         // alias at work
         logger.info("--> getting f* for index *bac");
@@ -1008,8 +1006,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(0).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("foo").addIndices("*bac").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("foo").addIndices("*bac").get().getAliases().isEmpty());
 
         logger.info("--> getting foo for index foobar");
         getResponse = admin().indices().prepareGetAliases("foo").addIndices("foobar").get();
@@ -1020,8 +1017,7 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().get("foobar").get(0).getFilter(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getIndexRouting(), nullValue());
         assertThat(getResponse.getAliases().get("foobar").get(0).getSearchRouting(), nullValue());
-        existsResponse = admin().indices().prepareAliasesExist("foo").addIndices("foobar").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("foo").addIndices("foobar").get().getAliases().isEmpty());
 
         for (String aliasName : new String[] { null, "_all", "*" }) {
             logger.info("--> getting {} alias for index foobar", aliasName);
@@ -1044,17 +1040,15 @@ public void testIndicesGetAliases() throws Exception {
         assertThat(getResponse.getAliases().size(), equalTo(2));
         assertThat(getResponse.getAliases().get("foobar").size(), equalTo(4));
         assertThat(getResponse.getAliases().get("bazbar").size(), equalTo(2));
-        existsResponse = admin().indices().prepareAliasesExist("*").addIndices("*bac").get();
-        assertThat(existsResponse.exists(), equalTo(true));
+        assertFalse(admin().indices().prepareGetAliases("*").addIndices("*bac").get().getAliases().isEmpty());
 
         assertAcked(admin().indices().prepareAliases().removeAlias("foobar", "foo"));
 
         getResponse = admin().indices().prepareGetAliases("foo").addIndices("foobar").get();
-        for (final ObjectObjectCursor<String, List<AliasMetadata>> entry : getResponse.getAliases()) {
-            assertTrue(entry.value.isEmpty());
+        for (final List<AliasMetadata> entry : getResponse.getAliases().values()) {
+            assertTrue(entry.isEmpty());
         }
-        existsResponse = admin().indices().prepareAliasesExist("foo").addIndices("foobar").get();
-        assertThat(existsResponse.exists(), equalTo(false));
+        assertTrue(admin().indices().prepareGetAliases("foo").addIndices("foobar").get().getAliases().isEmpty());
     }
 
     public void testGetAllAliasesWorks() {
@@ -1094,7 +1088,7 @@ public void testCreateIndexWithAliasesInSource() throws Exception {
                     + "        \"alias4\" : {\"is_hidden\":  true}\n"
                     + "    }\n"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -1226,7 +1220,7 @@ public void testAliasesWithBlocks() {
                 );
                 assertAliasesVersionIncreases("test", () -> assertAcked(admin().indices().prepareAliases().removeAlias("test", "alias1")));
                 assertThat(admin().indices().prepareGetAliases("alias2").execute().actionGet().getAliases().get("test").size(), equalTo(1));
-                assertThat(admin().indices().prepareAliasesExist("alias2").get().exists(), equalTo(true));
+                assertFalse(admin().indices().prepareGetAliases("alias2").get().getAliases().isEmpty());
             } finally {
                 disableIndexBlock("test", block);
             }
@@ -1244,8 +1238,7 @@ public void testAliasesWithBlocks() {
                 () -> assertBlocked(admin().indices().prepareAliases().removeAlias("test", "alias2"), INDEX_READ_ONLY_BLOCK)
             );
             assertThat(admin().indices().prepareGetAliases("alias2").execute().actionGet().getAliases().get("test").size(), equalTo(1));
-            assertThat(admin().indices().prepareAliasesExist("alias2").get().exists(), equalTo(true));
-
+            assertFalse(admin().indices().prepareGetAliases("alias2").get().getAliases().isEmpty());
         } finally {
             disableIndexBlock("test", SETTING_READ_ONLY);
         }
@@ -1262,8 +1255,7 @@ public void testAliasesWithBlocks() {
                 () -> assertBlocked(admin().indices().prepareAliases().removeAlias("test", "alias2"), INDEX_METADATA_BLOCK)
             );
             assertBlocked(admin().indices().prepareGetAliases("alias2"), INDEX_METADATA_BLOCK);
-            assertBlocked(admin().indices().prepareAliasesExist("alias2"), INDEX_METADATA_BLOCK);
-
+            assertBlocked(admin().indices().prepareGetAliases("alias2"), INDEX_METADATA_BLOCK);
         } finally {
             disableIndexBlock("test", SETTING_BLOCKS_METADATA);
         }
@@ -1288,12 +1280,12 @@ public void testAliasActionRemoveIndex() throws InterruptedException, ExecutionE
 
         assertAcked(client().admin().indices().prepareAliases().removeIndex("foo*"));
         assertFalse(client().admin().indices().prepareExists("foo_foo").execute().actionGet().isExists());
-        assertTrue(admin().indices().prepareAliasesExist("foo").get().exists());
+        assertFalse(admin().indices().prepareGetAliases("foo").get().getAliases().isEmpty());
         assertTrue(client().admin().indices().prepareExists("bar_bar").execute().actionGet().isExists());
-        assertTrue(admin().indices().prepareAliasesExist("foo").setIndices("bar_bar").get().exists());
+        assertFalse(admin().indices().prepareGetAliases("foo").setIndices("bar_bar").get().getAliases().isEmpty());
 
         assertAcked(client().admin().indices().prepareAliases().removeIndex("bar_bar"));
-        assertFalse(admin().indices().prepareAliasesExist("foo").get().exists());
+        assertTrue(admin().indices().prepareGetAliases("foo").get().getAliases().isEmpty());
         assertFalse(client().admin().indices().prepareExists("bar_bar").execute().actionGet().isExists());
     }
 
@@ -1389,12 +1381,13 @@ public void testIndexingAndQueryingHiddenAliases() throws Exception {
         ensureGreen();
 
         // Put a couple docs in each index directly
-        IndexResponse res = client().index(indexRequest(nonWriteIndex).id("1").source(source("1", "nonwrite"), XContentType.JSON)).get();
+        IndexResponse res = client().index(indexRequest(nonWriteIndex).id("1").source(source("1", "nonwrite"), MediaTypeRegistry.JSON))
+            .get();
         assertThat(res.status().getStatus(), equalTo(201));
-        res = client().index(indexRequest(writeIndex).id("2").source(source("2", "writeindex"), XContentType.JSON)).get();
+        res = client().index(indexRequest(writeIndex).id("2").source(source("2", "writeindex"), MediaTypeRegistry.JSON)).get();
         assertThat(res.status().getStatus(), equalTo(201));
         // And through the alias
-        res = client().index(indexRequest(alias).id("3").source(source("3", "through alias"), XContentType.JSON)).get();
+        res = client().index(indexRequest(alias).id("3").source(source("3", "through alias"), MediaTypeRegistry.JSON)).get();
         assertThat(res.status().getStatus(), equalTo(201));
 
         refresh(writeIndex, nonWriteIndex);
diff --git a/server/src/internalClusterTest/java/org/opensearch/blocks/CreateIndexBlockIT.java b/server/src/internalClusterTest/java/org/opensearch/blocks/CreateIndexBlockIT.java
new file mode 100644
index 0000000000000..3c1f1e83f7481
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/blocks/CreateIndexBlockIT.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.blocks;
+
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+
+import static org.opensearch.test.OpenSearchIntegTestCase.client;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertBlocked;
+
+public class CreateIndexBlockIT extends OpenSearchIntegTestCase {
+
+    public void testBlockCreateIndex() {
+        setCreateIndexBlock("true");
+        assertBlocked(client().admin().indices().prepareCreate("uncreated-idx"), Metadata.CLUSTER_CREATE_INDEX_BLOCK);
+        setCreateIndexBlock("false");
+        assertAcked(client().admin().indices().prepareCreate("created-idx").execute().actionGet());
+    }
+
+    @After
+    public void cleanup() throws Exception {
+        Settings settings = Settings.builder().putNull(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey()).build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setTransientSettings(settings).get());
+    }
+
+    private void setCreateIndexBlock(String value) {
+        Settings settings = Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), value).build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setTransientSettings(settings).get());
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/blocks/SimpleBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/blocks/SimpleBlocksIT.java
index 8ede3e25b2e1a..a7354dddfd16d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/blocks/SimpleBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/blocks/SimpleBlocksIT.java
@@ -38,7 +38,6 @@
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsResponse;
 import org.opensearch.action.admin.indices.readonly.AddIndexBlockRequestBuilder;
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequestBuilder;
-
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.support.ActiveShardCount;
diff --git a/server/src/internalClusterTest/java/org/opensearch/broadcast/BroadcastActionsIT.java b/server/src/internalClusterTest/java/org/opensearch/broadcast/BroadcastActionsIT.java
index f9f99eb2662b0..96b8c63f6c2ba 100644
--- a/server/src/internalClusterTest/java/org/opensearch/broadcast/BroadcastActionsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/broadcast/BroadcastActionsIT.java
@@ -33,8 +33,8 @@
 package org.opensearch.broadcast;
 
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/bwcompat/RecoveryWithUnsupportedIndicesIT.java b/server/src/internalClusterTest/java/org/opensearch/bwcompat/RecoveryWithUnsupportedIndicesIT.java
index 047584c1f13cb..158ed107b79c3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/bwcompat/RecoveryWithUnsupportedIndicesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/bwcompat/RecoveryWithUnsupportedIndicesIT.java
@@ -31,14 +31,6 @@
 
 package org.opensearch.bwcompat;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.nio.file.DirectoryStream;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.List;
-
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.ExceptionsHelper;
@@ -48,6 +40,14 @@
 import org.opensearch.gateway.CorruptStateException;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
 import static org.hamcrest.Matchers.containsString;
 
 @LuceneTestCase.SuppressCodecs("*")
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterAwarenessHealthIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterAwarenessHealthIT.java
new file mode 100644
index 0000000000000..9e6d2a6d385c7
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterAwarenessHealthIT.java
@@ -0,0 +1,244 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.cluster.awarenesshealth.ClusterAwarenessAttributesHealth;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.test.NodeRoles.onlyRole;
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class ClusterAwarenessHealthIT extends OpenSearchIntegTestCase {
+
+    public void testAwarenessAttributeHealthSucceeded() {
+        createIndex("test");
+        ensureGreen();
+
+        for (final String node : internalCluster().getNodeNames()) {
+            // a very high time out, which should never fire due to the local flag
+            logger.info("--> getting cluster health on [{}]", node);
+            final ClusterHealthResponse health = client(node).admin()
+                .cluster()
+                .prepareHealth()
+                .setTimeout("30s")
+                .setLevel("awareness_attributes")
+                .setAwarenessAttribute("zone")
+                .get("10s");
+
+            assertFalse("timed out on " + node, health.isTimedOut());
+            assertThat(
+                "health status on " + node,
+                health.getClusterAwarenessHealth().getClusterAwarenessAttributesHealthMap().size(),
+                equalTo(1)
+            );
+        }
+    }
+
+    public void testAwarenessAttributeHealthValidationFailed() {
+        createIndex("test");
+        ensureGreen();
+        for (final String node : internalCluster().getNodeNames()) {
+            // a very high time out, which should never fire due to the local flag
+            logger.info("--> getting cluster health on [{}]", node);
+            try {
+                final ClusterHealthResponse health = client(node).admin()
+                    .cluster()
+                    .prepareHealth()
+                    .setTimeout("30s")
+                    .setAwarenessAttribute("zone")
+                    .get("10s");
+            } catch (Exception exception) {
+                assertThat(
+                    exception.getMessage(),
+                    equalTo("Validation Failed: 1: level=awareness_attributes is required with awareness_attribute parameter;")
+                );
+            }
+        }
+    }
+
+    public void testAwarenessAttributeHealthValidationFailedOnIndexHealth() {
+        createIndex("test");
+        ensureGreen();
+        for (final String node : internalCluster().getNodeNames()) {
+            // a very high time out, which should never fire due to the local flag
+            logger.info("--> getting cluster health on [{}]", node);
+            try {
+                final ClusterHealthResponse health = client(node).admin()
+                    .cluster()
+                    .prepareHealth("test")
+                    .setTimeout("30s")
+                    .setLevel("awareness_attributes")
+                    .setAwarenessAttribute("zone")
+                    .get("10s");
+            } catch (Exception exception) {
+                assertThat(
+                    exception.getMessage(),
+                    equalTo("Validation Failed: 1: awareness_attribute is not a supported parameter with index health;")
+                );
+            }
+        }
+    }
+
+    public void testAwarenessAttributeHealth() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'd' & 'e' & 'f'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "d")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "e")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "f")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        final ClusterHealthResponse health = client(dataNodes.get(0)).admin()
+            .cluster()
+            .prepareHealth()
+            .setTimeout("30s")
+            .setLevel("awareness_attributes")
+            .setAwarenessAttribute("zone")
+            .get("10s");
+
+        ensureStableCluster(6);
+        assertThat(health.getClusterAwarenessHealth().getClusterAwarenessAttributesHealthMap().size(), equalTo(1));
+        Map<String, ClusterAwarenessAttributesHealth> attributes = health.getClusterAwarenessHealth()
+            .getClusterAwarenessAttributesHealthMap();
+        for (String attribute : attributes.keySet()) {
+            String attributeName = attributes.get(attribute).getAwarenessAttributeName();
+            assertThat(attributeName, equalTo("zone"));
+            assertThat(attributes.get(attribute).getAwarenessAttributeHealthMap().size(), equalTo(3));
+        }
+    }
+
+    public void testAwarenessAttributeHealthAttributeDoesNotExists() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'd' & 'e' & 'f'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "d")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "e")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "f")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        final ClusterHealthResponse health = client(dataNodes.get(0)).admin()
+            .cluster()
+            .prepareHealth()
+            .setTimeout("30s")
+            .setLevel("awareness_attributes")
+            .setAwarenessAttribute("rack")
+            .get("10s");
+
+        ensureStableCluster(6);
+        assertThat(health.getClusterAwarenessHealth().getClusterAwarenessAttributesHealthMap().size(), equalTo(1));
+        Map<String, ClusterAwarenessAttributesHealth> attributes = health.getClusterAwarenessHealth()
+            .getClusterAwarenessAttributesHealthMap();
+        for (String attribute : attributes.keySet()) {
+            String attributeName = attributes.get(attribute).getAwarenessAttributeName();
+            assertThat(attributeName, equalTo("rack"));
+            assertThat(attributes.get(attribute).getAwarenessAttributeHealthMap().size(), equalTo(0));
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterHealthIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterHealthIT.java
index 393ab8e5a7544..d63b87cbee6f7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterHealthIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterHealthIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
 import org.opensearch.action.support.IndicesOptions;
@@ -42,10 +41,11 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -60,7 +60,7 @@ public class ClusterHealthIT extends OpenSearchIntegTestCase {
 
     public void testSimpleLocalHealth() {
         createIndex("test");
-        ensureGreen(); // master should think it's green now.
+        ensureGreen(); // cluster-manager should think it's green now.
 
         for (final String node : internalCluster().getNodeNames()) {
             // a very high time out, which should never fire due to the local flag
@@ -307,7 +307,10 @@ public void testWaitForEventsRetriesIfOtherConditionsNotMet() {
             .execute();
 
         final AtomicBoolean keepSubmittingTasks = new AtomicBoolean(true);
-        final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, internalCluster().getMasterName());
+        final ClusterService clusterService = internalCluster().getInstance(
+            ClusterService.class,
+            internalCluster().getClusterManagerName()
+        );
         final PlainActionFuture<Void> completionFuture = new PlainActionFuture<>();
         clusterService.submitStateUpdateTask("looping task", new ClusterStateUpdateTask(Priority.LOW) {
             @Override
@@ -336,7 +339,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
             assertFalse(client().admin().cluster().prepareHealth("index").setWaitForGreenStatus().get().isTimedOut());
 
             // at this point the original health response should not have returned: there was never a point where the index was green AND
-            // the master had processed all pending tasks above LANGUID priority.
+            // the cluster-manager had processed all pending tasks above LANGUID priority.
             assertFalse(healthResponseFuture.isDone());
             keepSubmittingTasks.set(false);
             assertFalse(healthResponseFuture.actionGet(TimeValue.timeValueSeconds(30)).isTimedOut());
@@ -346,14 +349,14 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         }
     }
 
-    public void testHealthOnMasterFailover() throws Exception {
+    public void testHealthOnClusterManagerFailover() throws Exception {
         final String node = internalCluster().startDataOnlyNode();
         final boolean withIndex = randomBoolean();
         if (withIndex) {
-            // Create index with many shards to provoke the health request to wait (for green) while master is being shut down.
-            // Notice that this is set to 0 after the test completed starting a number of health requests and master restarts.
+            // Create index with many shards to provoke the health request to wait (for green) while cluster-manager is being shut down.
+            // Notice that this is set to 0 after the test completed starting a number of health requests and cluster-manager restarts.
             // This ensures that the cluster is yellow when the health request is made, making the health request wait on the observer,
-            // triggering a call to observer.onClusterServiceClose when master is shutdown.
+            // triggering a call to observer.onClusterServiceClose when cluster-manager is shutdown.
             createIndex(
                 "test",
                 Settings.builder()
@@ -364,8 +367,8 @@ public void testHealthOnMasterFailover() throws Exception {
             );
         }
         final List<ActionFuture<ClusterHealthResponse>> responseFutures = new ArrayList<>();
-        // Run a few health requests concurrent to master fail-overs against a data-node to make sure master failover is handled
-        // without exceptions
+        // Run a few health requests concurrent to cluster-manager fail-overs against a data-node
+        // to make sure cluster-manager failover is handled without exceptions
         final int iterations = withIndex ? 10 : 20;
         for (int i = 0; i < iterations; ++i) {
             responseFutures.add(
@@ -374,10 +377,10 @@ public void testHealthOnMasterFailover() throws Exception {
                     .prepareHealth()
                     .setWaitForEvents(Priority.LANGUID)
                     .setWaitForGreenStatus()
-                    .setMasterNodeTimeout(TimeValue.timeValueMinutes(2))
+                    .setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(2))
                     .execute()
             );
-            internalCluster().restartNode(internalCluster().getMasterName(), InternalTestCluster.EMPTY_CALLBACK);
+            internalCluster().restartNode(internalCluster().getClusterManagerName(), InternalTestCluster.EMPTY_CALLBACK);
         }
         if (withIndex) {
             assertAcked(
@@ -394,9 +397,12 @@ public void testHealthOnMasterFailover() throws Exception {
         }
     }
 
-    public void testWaitForEventsTimesOutIfMasterBusy() {
+    public void testWaitForEventsTimesOutIfClusterManagerBusy() {
         final AtomicBoolean keepSubmittingTasks = new AtomicBoolean(true);
-        final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, internalCluster().getMasterName());
+        final ClusterService clusterService = internalCluster().getInstance(
+            ClusterService.class,
+            internalCluster().getClusterManagerName()
+        );
         final PlainActionFuture<Void> completionFuture = new PlainActionFuture<>();
         clusterService.submitStateUpdateTask("looping task", new ClusterStateUpdateTask(Priority.LOW) {
             @Override
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterInfoServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterInfoServiceIT.java
index e8ea0bb933a3e..35b8bdf3dafe5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterInfoServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterInfoServiceIT.java
@@ -32,9 +32,7 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsAction;
 import org.opensearch.action.admin.indices.stats.IndicesStatsAction;
@@ -46,23 +44,23 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndexDescriptor;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SystemIndexPlugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
-
 import org.hamcrest.Matchers;
 
 import java.util.Arrays;
@@ -70,6 +68,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -166,34 +165,39 @@ public void testClusterInfoServiceCollectsInformation() {
         }
         ensureGreen(indexName);
         InternalTestCluster internalTestCluster = internalCluster();
-        // Get the cluster info service on the master node
+        // Get the cluster info service on the cluster-manager node
         final InternalClusterInfoService infoService = (InternalClusterInfoService) internalTestCluster.getInstance(
             ClusterInfoService.class,
-            internalTestCluster.getMasterName()
+            internalTestCluster.getClusterManagerName()
         );
         infoService.setUpdateFrequency(TimeValue.timeValueMillis(200));
         ClusterInfo info = infoService.refresh();
         assertNotNull("info should not be null", info);
-        ImmutableOpenMap<String, DiskUsage> leastUsages = info.getNodeLeastAvailableDiskUsages();
-        ImmutableOpenMap<String, DiskUsage> mostUsages = info.getNodeMostAvailableDiskUsages();
-        ImmutableOpenMap<String, Long> shardSizes = info.shardSizes;
+        final Map<String, DiskUsage> leastUsages = info.getNodeLeastAvailableDiskUsages();
+        final Map<String, DiskUsage> mostUsages = info.getNodeMostAvailableDiskUsages();
+        final Map<String, Long> shardSizes = info.shardSizes;
         assertNotNull(leastUsages);
         assertNotNull(shardSizes);
         assertThat("some usages are populated", leastUsages.values().size(), Matchers.equalTo(2));
         assertThat("some shard sizes are populated", shardSizes.values().size(), greaterThan(0));
-        for (ObjectCursor<DiskUsage> usage : leastUsages.values()) {
-            logger.info("--> usage: {}", usage.value);
-            assertThat("usage has be retrieved", usage.value.getFreeBytes(), greaterThan(0L));
+        for (Map.Entry<String, DiskUsage> usage : leastUsages.entrySet()) {
+            logger.info("--> usage: {}", usage.getValue());
+            assertThat("usage has be retrieved", usage.getValue().getFreeBytes(), greaterThan(0L));
         }
-        for (ObjectCursor<DiskUsage> usage : mostUsages.values()) {
-            logger.info("--> usage: {}", usage.value);
-            assertThat("usage has be retrieved", usage.value.getFreeBytes(), greaterThan(0L));
+        for (DiskUsage usage : mostUsages.values()) {
+            logger.info("--> usage: {}", usage);
+            assertThat("usage has be retrieved", usage.getFreeBytes(), greaterThan(0L));
         }
-        for (ObjectCursor<Long> size : shardSizes.values()) {
-            logger.info("--> shard size: {}", size.value);
-            assertThat("shard size is greater than 0", size.value, greaterThanOrEqualTo(0L));
+        for (Long size : shardSizes.values()) {
+            logger.info("--> shard size: {}", size);
+            assertThat("shard size is greater than 0", size, greaterThanOrEqualTo(0L));
         }
-        ClusterService clusterService = internalTestCluster.getInstance(ClusterService.class, internalTestCluster.getMasterName());
+
+        final Map<String, FileCacheStats> nodeFileCacheStats = info.nodeFileCacheStats;
+        assertNotNull(nodeFileCacheStats);
+        assertThat("file cache is empty on non search nodes", nodeFileCacheStats.size(), Matchers.equalTo(0));
+
+        ClusterService clusterService = internalTestCluster.getInstance(ClusterService.class, internalTestCluster.getClusterManagerName());
         ClusterState state = clusterService.state();
         for (ShardRouting shard : state.routingTable().allShards()) {
             String dataPath = info.getDataPath(shard);
@@ -210,6 +214,28 @@ public void testClusterInfoServiceCollectsInformation() {
         }
     }
 
+    public void testClusterInfoServiceCollectsFileCacheInformation() {
+        internalCluster().startNodes(1);
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(2);
+
+        InternalTestCluster internalTestCluster = internalCluster();
+        // Get the cluster info service on the cluster-manager node
+        final InternalClusterInfoService infoService = (InternalClusterInfoService) internalTestCluster.getInstance(
+            ClusterInfoService.class,
+            internalTestCluster.getClusterManagerName()
+        );
+        infoService.setUpdateFrequency(TimeValue.timeValueMillis(200));
+        ClusterInfo info = infoService.refresh();
+        assertNotNull("info should not be null", info);
+        final Map<String, FileCacheStats> nodeFileCacheStats = info.nodeFileCacheStats;
+        assertNotNull(nodeFileCacheStats);
+        assertThat("file cache is enabled on both search nodes", nodeFileCacheStats.size(), Matchers.equalTo(2));
+
+        for (FileCacheStats fileCacheStats : nodeFileCacheStats.values()) {
+            assertThat("file cache is non empty", fileCacheStats.getTotal().getBytes(), greaterThan(0L));
+        }
+    }
+
     public void testClusterInfoServiceInformationClearOnError() {
         internalCluster().startNodes(
             2,
@@ -221,7 +247,7 @@ public void testClusterInfoServiceInformationClearOnError() {
         InternalTestCluster internalTestCluster = internalCluster();
         InternalClusterInfoService infoService = (InternalClusterInfoService) internalTestCluster.getInstance(
             ClusterInfoService.class,
-            internalTestCluster.getMasterName()
+            internalTestCluster.getClusterManagerName()
         );
         // get one healthy sample
         ClusterInfo info = infoService.refresh();
@@ -231,7 +257,7 @@ public void testClusterInfoServiceInformationClearOnError() {
 
         MockTransportService mockTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            internalTestCluster.getMasterName()
+            internalTestCluster.getClusterManagerName()
         );
 
         final AtomicBoolean timeout = new AtomicBoolean(false);
@@ -272,7 +298,7 @@ public void testClusterInfoServiceInformationClearOnError() {
 
         // now we cause an exception
         timeout.set(false);
-        ActionFilters actionFilters = internalTestCluster.getInstance(ActionFilters.class, internalTestCluster.getMasterName());
+        ActionFilters actionFilters = internalTestCluster.getInstance(ActionFilters.class, internalTestCluster.getClusterManagerName());
         BlockingActionFilter blockingActionFilter = null;
         for (ActionFilter filter : actionFilters.filters()) {
             if (filter instanceof BlockingActionFilter) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterStateDiffIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterStateDiffIT.java
index ea1daffaf770d..44ab41fb5a8d3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterStateDiffIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/ClusterStateDiffIT.java
@@ -32,12 +32,11 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexGraveyard;
 import org.opensearch.cluster.metadata.IndexGraveyardTests;
@@ -55,18 +54,17 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.gateway.GatewayService;
-import org.opensearch.index.Index;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfoTests;
@@ -75,6 +73,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import static java.util.Collections.emptyList;
@@ -93,9 +92,13 @@
 public class ClusterStateDiffIT extends OpenSearchIntegTestCase {
     public void testClusterStateDiffSerialization() throws Exception {
         NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(ClusterModule.getNamedWriteables());
-        DiscoveryNode masterNode = randomNode("master");
+        DiscoveryNode clusterManagerNode = randomNode("cluster-manager");
         DiscoveryNode otherNode = randomNode("other");
-        DiscoveryNodes discoveryNodes = DiscoveryNodes.builder().add(masterNode).add(otherNode).localNodeId(masterNode.getId()).build();
+        DiscoveryNodes discoveryNodes = DiscoveryNodes.builder()
+            .add(clusterManagerNode)
+            .add(otherNode)
+            .localNodeId(clusterManagerNode.getId())
+            .build();
         ClusterState clusterState = ClusterState.builder(new ClusterName("test")).nodes(discoveryNodes).build();
         ClusterState clusterStateFromDiffs = ClusterState.Builder.fromBytes(
             ClusterState.Builder.toBytes(clusterState),
@@ -168,9 +171,9 @@ public void testClusterStateDiffSerialization() throws Exception {
                 assertThat(clusterStateFromDiffs.nodes().getNodes(), equalTo(clusterState.nodes().getNodes()));
                 assertThat(clusterStateFromDiffs.nodes().getLocalNodeId(), equalTo(previousClusterStateFromDiffs.nodes().getLocalNodeId()));
                 assertThat(clusterStateFromDiffs.nodes().getNodes(), equalTo(clusterState.nodes().getNodes()));
-                for (ObjectCursor<String> node : clusterStateFromDiffs.nodes().getNodes().keys()) {
-                    DiscoveryNode node1 = clusterState.nodes().get(node.value);
-                    DiscoveryNode node2 = clusterStateFromDiffs.nodes().get(node.value);
+                for (final String node : clusterStateFromDiffs.nodes().getNodes().keySet()) {
+                    DiscoveryNode node1 = clusterState.nodes().get(node);
+                    DiscoveryNode node2 = clusterStateFromDiffs.nodes().get(node);
                     assertThat(node1.getVersion(), equalTo(node2.getVersion()));
                     assertThat(node1.getAddress(), equalTo(node2.getAddress()));
                     assertThat(node1.getAttributes(), equalTo(node2.getAttributes()));
@@ -252,7 +255,7 @@ private ClusterState.Builder randomNodes(ClusterState clusterState) {
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder(clusterState.nodes());
         List<String> nodeIds = randomSubsetOf(
             randomInt(clusterState.nodes().getNodes().size() - 1),
-            clusterState.nodes().getNodes().keys().toArray(String.class)
+            clusterState.nodes().getNodes().keySet().toArray(new String[0])
         );
         for (String nodeId : nodeIds) {
             if (nodeId.startsWith("node-")) {
@@ -278,7 +281,7 @@ private ClusterState.Builder randomRoutingTable(ClusterState clusterState) {
         if (numberOfIndices > 0) {
             List<String> randomIndices = randomSubsetOf(
                 randomInt(numberOfIndices - 1),
-                clusterState.routingTable().indicesRouting().keys().toArray(String.class)
+                clusterState.routingTable().indicesRouting().keySet().toArray(new String[0])
             );
             for (String index : randomIndices) {
                 if (randomBoolean()) {
@@ -287,7 +290,7 @@ private ClusterState.Builder randomRoutingTable(ClusterState clusterState) {
                     builder.add(
                         randomChangeToIndexRoutingTable(
                             clusterState.routingTable().indicesRouting().get(index),
-                            clusterState.nodes().getNodes().keys().toArray(String.class)
+                            clusterState.nodes().getNodes().keySet().toArray(new String[0])
                         )
                     );
                 }
@@ -295,7 +298,7 @@ private ClusterState.Builder randomRoutingTable(ClusterState clusterState) {
         }
         int additionalIndexCount = randomIntBetween(1, 20);
         for (int i = 0; i < additionalIndexCount; i++) {
-            builder.add(randomIndexRoutingTable("index-" + randomInt(), clusterState.nodes().getNodes().keys().toArray(String.class)));
+            builder.add(randomIndexRoutingTable("index-" + randomInt(), clusterState.nodes().getNodes().keySet().toArray(new String[0])));
         }
         return ClusterState.builder(clusterState).routingTable(builder.build());
     }
@@ -343,16 +346,16 @@ private IndexRoutingTable randomIndexRoutingTable(String index, String[] nodeIds
      */
     private IndexRoutingTable randomChangeToIndexRoutingTable(IndexRoutingTable original, String[] nodes) {
         IndexRoutingTable.Builder builder = IndexRoutingTable.builder(original.getIndex());
-        for (ObjectCursor<IndexShardRoutingTable> indexShardRoutingTable : original.shards().values()) {
+        for (var indexShardRoutingTable : original.shards().values()) {
             Set<String> availableNodes = Sets.newHashSet(nodes);
-            for (ShardRouting shardRouting : indexShardRoutingTable.value.shards()) {
+            for (ShardRouting shardRouting : indexShardRoutingTable.shards()) {
                 availableNodes.remove(shardRouting.currentNodeId());
                 if (shardRouting.relocating()) {
                     availableNodes.remove(shardRouting.relocatingNodeId());
                 }
             }
 
-            for (ShardRouting shardRouting : indexShardRoutingTable.value.shards()) {
+            for (ShardRouting shardRouting : indexShardRoutingTable.shards()) {
                 final ShardRouting updatedShardRouting = randomChange(shardRouting, availableNodes);
                 availableNodes.remove(updatedShardRouting.currentNodeId());
                 if (shardRouting.relocating()) {
@@ -392,9 +395,9 @@ private ClusterState.Builder randomBlocks(ClusterState clusterState) {
     private ClusterBlock randomGlobalBlock() {
         switch (randomInt(2)) {
             case 0:
-                return NoMasterBlockService.NO_MASTER_BLOCK_ALL;
+                return NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL;
             case 1:
-                return NoMasterBlockService.NO_MASTER_BLOCK_WRITES;
+                return NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES;
             default:
                 return GatewayService.STATE_NOT_RECOVERED_BLOCK;
         }
@@ -408,7 +411,7 @@ private interface RandomClusterPart<T> {
         /**
          * Returns list of parts from metadata
          */
-        ImmutableOpenMap<String, T> parts(ClusterState clusterState);
+        Map<String, T> parts(ClusterState clusterState);
 
         /**
          * Puts the part back into metadata
@@ -438,12 +441,12 @@ private interface RandomClusterPart<T> {
      */
     private <T> ClusterState randomClusterStateParts(ClusterState clusterState, String prefix, RandomClusterPart<T> randomPart) {
         ClusterState.Builder builder = ClusterState.builder(clusterState);
-        ImmutableOpenMap<String, T> parts = randomPart.parts(clusterState);
+        final Map<String, T> parts = randomPart.parts(clusterState);
         int partCount = parts.size();
         if (partCount > 0) {
             List<String> randomParts = randomSubsetOf(
                 randomInt(partCount - 1),
-                randomPart.parts(clusterState).keys().toArray(String.class)
+                randomPart.parts(clusterState).keySet().toArray(new String[0])
             );
             for (String part : randomParts) {
                 if (randomBoolean()) {
@@ -522,7 +525,7 @@ private interface RandomPart<T> {
         /**
          * Returns list of parts from metadata
          */
-        ImmutableOpenMap<String, T> parts(Metadata metadata);
+        Map<String, T> parts(Metadata metadata);
 
         /**
          * Puts the part back into metadata
@@ -552,10 +555,10 @@ private interface RandomPart<T> {
      */
     private <T> Metadata randomParts(Metadata metadata, String prefix, RandomPart<T> randomPart) {
         Metadata.Builder builder = Metadata.builder(metadata);
-        ImmutableOpenMap<String, T> parts = randomPart.parts(metadata);
+        final Map<String, T> parts = randomPart.parts(metadata);
         int partCount = parts.size();
         if (partCount > 0) {
-            List<String> randomParts = randomSubsetOf(randomInt(partCount - 1), randomPart.parts(metadata).keys().toArray(String.class));
+            List<String> randomParts = randomSubsetOf(randomInt(partCount - 1), randomPart.parts(metadata).keySet().toArray(new String[0]));
             for (String part : randomParts) {
                 if (randomBoolean()) {
                     randomPart.remove(builder, part);
@@ -579,7 +582,7 @@ private Metadata randomIndices(Metadata metadata) {
         return randomParts(metadata, "index", new RandomPart<IndexMetadata>() {
 
             @Override
-            public ImmutableOpenMap<String, IndexMetadata> parts(Metadata metadata) {
+            public Map<String, IndexMetadata> parts(Metadata metadata) {
                 return metadata.indices();
             }
 
@@ -617,7 +620,7 @@ public IndexMetadata randomChange(IndexMetadata part) {
                         break;
                     case 1:
                         if (randomBoolean() && part.getAliases().isEmpty() == false) {
-                            builder.removeAlias(randomFrom(part.getAliases().keys().toArray(String.class)));
+                            builder.removeAlias(randomFrom(part.getAliases().keySet().toArray(new String[0])));
                         } else {
                             builder.putAlias(AliasMetadata.builder(randomAlphaOfLength(10)));
                         }
@@ -641,7 +644,7 @@ public IndexMetadata randomChange(IndexMetadata part) {
     private Metadata randomTemplates(Metadata metadata) {
         return randomParts(metadata, "template", new RandomPart<IndexTemplateMetadata>() {
             @Override
-            public ImmutableOpenMap<String, IndexTemplateMetadata> parts(Metadata metadata) {
+            public Map<String, IndexTemplateMetadata> parts(Metadata metadata) {
                 return metadata.templates();
             }
 
@@ -698,7 +701,7 @@ private Metadata randomMetadataCustoms(final Metadata metadata) {
         return randomParts(metadata, "custom", new RandomPart<Metadata.Custom>() {
 
             @Override
-            public ImmutableOpenMap<String, Metadata.Custom> parts(Metadata metadata) {
+            public Map<String, Metadata.Custom> parts(Metadata metadata) {
                 return metadata.customs();
             }
 
@@ -740,7 +743,7 @@ private ClusterState.Builder randomClusterStateCustoms(final ClusterState cluste
         return ClusterState.builder(randomClusterStateParts(clusterState, "custom", new RandomClusterPart<ClusterState.Custom>() {
 
             @Override
-            public ImmutableOpenMap<String, ClusterState.Custom> parts(ClusterState clusterState) {
+            public Map<String, ClusterState.Custom> parts(ClusterState clusterState) {
                 return clusterState.customs();
             }
 
@@ -764,15 +767,16 @@ public ClusterState.Custom randomCreate(String name) {
                                     new Snapshot(randomName("repo"), new SnapshotId(randomName("snap"), UUIDs.randomBase64UUID())),
                                     randomBoolean(),
                                     randomBoolean(),
-                                    SnapshotsInProgressSerializationTests.randomState(ImmutableOpenMap.of()),
+                                    SnapshotsInProgressSerializationTests.randomState(Map.of()),
                                     Collections.emptyList(),
                                     Collections.emptyList(),
                                     Math.abs(randomLong()),
                                     randomIntBetween(0, 1000),
-                                    ImmutableOpenMap.of(),
+                                    Map.of(),
                                     null,
                                     SnapshotInfoTests.randomUserMetadata(),
-                                    randomVersion(random())
+                                    randomVersion(random()),
+                                    false
                                 )
                             )
                         );
@@ -783,7 +787,7 @@ public ClusterState.Custom randomCreate(String name) {
                                 new Snapshot(randomName("repo"), new SnapshotId(randomName("snap"), UUIDs.randomBase64UUID())),
                                 RestoreInProgress.State.fromValue((byte) randomIntBetween(0, 3)),
                                 emptyList(),
-                                ImmutableOpenMap.of()
+                                Map.of()
                             )
                         ).build();
                     default:
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumClusterManagerNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumClusterManagerNodesIT.java
new file mode 100644
index 0000000000000..4c8bf24b1655a
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumClusterManagerNodesIT.java
@@ -0,0 +1,427 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
+import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsRequest;
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.set.Sets;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoTimeout;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+
+@ClusterScope(scope = Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class MinimumClusterManagerNodesIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        final HashSet<Class<? extends Plugin>> classes = new HashSet<>(super.nodePlugins());
+        classes.add(MockTransportService.TestPlugin.class);
+        return classes;
+    }
+
+    public void testTwoNodesNoClusterManagerBlock() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(1);
+
+        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
+
+        logger.info("--> start first node");
+        String node1Name = internalCluster().startNode(settings);
+
+        logger.info("--> should be blocked, no cluster-manager...");
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(true));
+        assertThat(state.nodes().getSize(), equalTo(1)); // verify that we still see the local node in the cluster state
+
+        logger.info("--> start second node, cluster should be formed");
+        String node2Name = internalCluster().startNode(settings);
+
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("2")
+            .execute()
+            .actionGet();
+        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
+
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertThat(state.nodes().getSize(), equalTo(2));
+        assertThat(state.metadata().indices().containsKey("test"), equalTo(false));
+
+        createIndex("test");
+        NumShards numShards = getNumShards("test");
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").execute().actionGet();
+        }
+        // make sure that all shards recovered before trying to flush
+        assertThat(
+            client().admin()
+                .cluster()
+                .prepareHealth("test")
+                .setWaitForActiveShards(numShards.totalNumShards)
+                .execute()
+                .actionGet()
+                .getActiveShards(),
+            equalTo(numShards.totalNumShards)
+        );
+        // flush for simpler debugging
+        flushAndRefresh();
+
+        logger.info("--> verify we get the data back");
+        for (int i = 0; i < 10; i++) {
+            assertThat(
+                client().prepareSearch()
+                    .setSize(0)
+                    .setQuery(QueryBuilders.matchAllQuery())
+                    .execute()
+                    .actionGet()
+                    .getHits()
+                    .getTotalHits().value,
+                equalTo(100L)
+            );
+        }
+
+        String clusterManagerNode = internalCluster().getClusterManagerName();
+        String otherNode = node1Name.equals(clusterManagerNode) ? node2Name : node1Name;
+        logger.info("--> add voting config exclusion for non-cluster-manager node, to be sure it's not elected");
+        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(otherNode)).get();
+        logger.info("--> stop cluster-manager node, no cluster-manager block should appear");
+        Settings clusterManagerDataPathSettings = internalCluster().dataPathSettings(clusterManagerNode);
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(clusterManagerNode));
+
+        assertBusy(() -> {
+            ClusterState clusterState = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+            assertTrue(clusterState.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
+        });
+
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(true));
+        // verify that both nodes are still in the cluster state but there is no cluster-manager
+        assertThat(state.nodes().getSize(), equalTo(2));
+        assertThat(state.nodes().getClusterManagerNode(), equalTo(null));
+
+        logger.info("--> starting the previous cluster-manager node again...");
+        node2Name = internalCluster().startNode(Settings.builder().put(settings).put(clusterManagerDataPathSettings).build());
+
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForYellowStatus()
+            .setWaitForNodes("2")
+            .execute()
+            .actionGet();
+        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
+
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertThat(state.nodes().getSize(), equalTo(2));
+        assertThat(state.metadata().indices().containsKey("test"), equalTo(true));
+
+        ensureGreen();
+
+        logger.info("--> verify we get the data back after cluster reform");
+        for (int i = 0; i < 10; i++) {
+            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
+        }
+
+        logger.info("--> clearing voting config exclusions");
+        ClearVotingConfigExclusionsRequest clearRequest = new ClearVotingConfigExclusionsRequest();
+        clearRequest.setWaitForRemoval(false);
+        client().execute(ClearVotingConfigExclusionsAction.INSTANCE, clearRequest).get();
+
+        clusterManagerNode = internalCluster().getClusterManagerName();
+        otherNode = node1Name.equals(clusterManagerNode) ? node2Name : node1Name;
+        logger.info("--> add voting config exclusion for cluster-manager node, to be sure it's not elected");
+        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(clusterManagerNode)).get();
+        logger.info("--> stop non-cluster-manager node, no cluster-manager block should appear");
+        Settings otherNodeDataPathSettings = internalCluster().dataPathSettings(otherNode);
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(otherNode));
+
+        assertBusy(() -> {
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+            assertThat(state1.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(true));
+        });
+
+        logger.info("--> starting the previous cluster-manager node again...");
+        internalCluster().startNode(Settings.builder().put(settings).put(otherNodeDataPathSettings).build());
+
+        ensureGreen();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("2")
+            .setWaitForGreenStatus()
+            .execute()
+            .actionGet();
+        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
+
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+        assertThat(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(false));
+
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertThat(state.nodes().getSize(), equalTo(2));
+        assertThat(state.metadata().indices().containsKey("test"), equalTo(true));
+
+        logger.info("Running Cluster Health");
+        ensureGreen();
+
+        logger.info("--> verify we the data back");
+        for (int i = 0; i < 10; i++) {
+            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
+        }
+    }
+
+    public void testThreeNodesNoClusterManagerBlock() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
+
+        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
+
+        logger.info("--> start first 2 nodes");
+        internalCluster().startNodes(2, settings);
+
+        ClusterState state;
+
+        assertBusy(() -> {
+            for (Client client : clients()) {
+                ClusterState state1 = client.admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+                assertThat(state1.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(true));
+            }
+        });
+
+        logger.info("--> start one more node");
+        internalCluster().startNode(settings);
+
+        ensureGreen();
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
+
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertThat(state.nodes().getSize(), equalTo(3));
+
+        createIndex("test");
+        NumShards numShards = getNumShards("test");
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").execute().actionGet();
+        }
+        ensureGreen();
+        // make sure that all shards recovered before trying to flush
+        assertThat(
+            client().admin()
+                .cluster()
+                .prepareHealth("test")
+                .setWaitForActiveShards(numShards.totalNumShards)
+                .execute()
+                .actionGet()
+                .isTimedOut(),
+            equalTo(false)
+        );
+        // flush for simpler debugging
+        client().admin().indices().prepareFlush().execute().actionGet();
+
+        refresh();
+        logger.info("--> verify we get the data back");
+        for (int i = 0; i < 10; i++) {
+            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
+        }
+
+        List<String> nonClusterManagerNodes = new ArrayList<>(
+            Sets.difference(
+                Sets.newHashSet(internalCluster().getNodeNames()),
+                Collections.singleton(internalCluster().getClusterManagerName())
+            )
+        );
+        Settings nonClusterManagerDataPathSettings1 = internalCluster().dataPathSettings(nonClusterManagerNodes.get(0));
+        Settings nonClusterManagerDataPathSettings2 = internalCluster().dataPathSettings(nonClusterManagerNodes.get(1));
+        internalCluster().stopRandomNonClusterManagerNode();
+        internalCluster().stopRandomNonClusterManagerNode();
+
+        logger.info("--> verify that there is no cluster-manager anymore on remaining node");
+        // spin here to wait till the state is set
+        assertBusy(() -> {
+            ClusterState st = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
+            assertThat(st.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID), equalTo(true));
+        });
+
+        logger.info("--> start back the 2 nodes ");
+        internalCluster().startNodes(nonClusterManagerDataPathSettings1, nonClusterManagerDataPathSettings2);
+
+        internalCluster().validateClusterFormed();
+        ensureGreen();
+
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertThat(state.nodes().getSize(), equalTo(3));
+
+        logger.info("--> verify we the data back");
+        for (int i = 0; i < 10; i++) {
+            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
+        }
+    }
+
+    public void testCannotCommitStateThreeNodes() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
+
+        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
+
+        internalCluster().startNodes(3, settings);
+        ensureStableCluster(3);
+
+        final String clusterManager = internalCluster().getClusterManagerName();
+        Set<String> otherNodes = new HashSet<>(Arrays.asList(internalCluster().getNodeNames()));
+        otherNodes.remove(clusterManager);
+        NetworkDisruption partition = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
+        internalCluster().setDisruptionScheme(partition);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicReference<Exception> failure = new AtomicReference<>();
+        logger.debug("--> submitting for cluster state to be rejected");
+        final ClusterService clusterManagerClusterService = internalCluster().clusterService(clusterManager);
+        clusterManagerClusterService.submitStateUpdateTask("test", new ClusterStateUpdateTask() {
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                latch.countDown();
+            }
+
+            @Override
+            public ClusterState execute(ClusterState currentState) throws Exception {
+                logger.debug("--> starting the disruption, preventing cluster state publishing");
+                partition.startDisrupting();
+                Metadata.Builder metadata = Metadata.builder(currentState.metadata())
+                    .persistentSettings(
+                        Settings.builder().put(currentState.metadata().persistentSettings()).put("_SHOULD_NOT_BE_THERE_", true).build()
+                    );
+                return ClusterState.builder(currentState).metadata(metadata).build();
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                failure.set(e);
+                latch.countDown();
+            }
+        });
+
+        logger.debug("--> waiting for cluster state to be processed/rejected");
+        latch.await();
+
+        assertThat(failure.get(), instanceOf(FailedToCommitClusterStateException.class));
+
+        logger.debug("--> check that there is no cluster-manager in minor partition");
+        assertBusy(() -> assertThat(clusterManagerClusterService.state().nodes().getClusterManagerNode(), nullValue()));
+
+        // let major partition to elect new cluster-manager, to ensure that old cluster-manager is not elected once partition is restored,
+        // otherwise persistent setting (which is a part of accepted state on old cluster-manager) will be propagated to other nodes
+        logger.debug("--> wait for cluster-manager to be elected in major partition");
+        assertBusy(() -> {
+            DiscoveryNode clusterManagerNode = internalCluster().client(randomFrom(otherNodes))
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode();
+            assertThat(clusterManagerNode, notNullValue());
+            assertThat(clusterManagerNode.getName(), not(equalTo(clusterManager)));
+        });
+
+        partition.stopDisrupting();
+
+        logger.debug("--> waiting for cluster to heal");
+        assertNoTimeout(client().admin().cluster().prepareHealth().setWaitForNodes("3").setWaitForEvents(Priority.LANGUID));
+
+        for (String node : internalCluster().getNodeNames()) {
+            Settings nodeSetting = internalCluster().clusterService(node).state().metadata().settings();
+            assertThat(
+                node + " processed the cluster state despite of a min cluster-manager node violation",
+                nodeSetting.get("_SHOULD_NOT_BE_THERE_"),
+                nullValue()
+            );
+        }
+
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumMasterNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumMasterNodesIT.java
deleted file mode 100644
index c3dc686921eb6..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/MinimumMasterNodesIT.java
+++ /dev/null
@@ -1,424 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.cluster;
-
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
-import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsAction;
-import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsRequest;
-import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
-import org.opensearch.client.Client;
-import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
-import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Priority;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
-import org.opensearch.test.disruption.NetworkDisruption;
-import org.opensearch.test.transport.MockTransportService;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicReference;
-
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoTimeout;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
-
-@ClusterScope(scope = Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
-public class MinimumMasterNodesIT extends OpenSearchIntegTestCase {
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        final HashSet<Class<? extends Plugin>> classes = new HashSet<>(super.nodePlugins());
-        classes.add(MockTransportService.TestPlugin.class);
-        return classes;
-    }
-
-    public void testTwoNodesNoMasterBlock() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(1);
-
-        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
-
-        logger.info("--> start first node");
-        String node1Name = internalCluster().startNode(settings);
-
-        logger.info("--> should be blocked, no master...");
-        ClusterState state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(true));
-        assertThat(state.nodes().getSize(), equalTo(1)); // verify that we still see the local node in the cluster state
-
-        logger.info("--> start second node, cluster should be formed");
-        String node2Name = internalCluster().startNode(settings);
-
-        ClusterHealthResponse clusterHealthResponse = client().admin()
-            .cluster()
-            .prepareHealth()
-            .setWaitForEvents(Priority.LANGUID)
-            .setWaitForNodes("2")
-            .execute()
-            .actionGet();
-        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
-
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-
-        state = client().admin().cluster().prepareState().execute().actionGet().getState();
-        assertThat(state.nodes().getSize(), equalTo(2));
-        assertThat(state.metadata().indices().containsKey("test"), equalTo(false));
-
-        createIndex("test");
-        NumShards numShards = getNumShards("test");
-        logger.info("--> indexing some data");
-        for (int i = 0; i < 100; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").execute().actionGet();
-        }
-        // make sure that all shards recovered before trying to flush
-        assertThat(
-            client().admin()
-                .cluster()
-                .prepareHealth("test")
-                .setWaitForActiveShards(numShards.totalNumShards)
-                .execute()
-                .actionGet()
-                .getActiveShards(),
-            equalTo(numShards.totalNumShards)
-        );
-        // flush for simpler debugging
-        flushAndRefresh();
-
-        logger.info("--> verify we get the data back");
-        for (int i = 0; i < 10; i++) {
-            assertThat(
-                client().prepareSearch()
-                    .setSize(0)
-                    .setQuery(QueryBuilders.matchAllQuery())
-                    .execute()
-                    .actionGet()
-                    .getHits()
-                    .getTotalHits().value,
-                equalTo(100L)
-            );
-        }
-
-        String masterNode = internalCluster().getMasterName();
-        String otherNode = node1Name.equals(masterNode) ? node2Name : node1Name;
-        logger.info("--> add voting config exclusion for non-master node, to be sure it's not elected");
-        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(otherNode)).get();
-        logger.info("--> stop master node, no master block should appear");
-        Settings masterDataPathSettings = internalCluster().dataPathSettings(masterNode);
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(masterNode));
-
-        assertBusy(() -> {
-            ClusterState clusterState = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-            assertTrue(clusterState.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
-        });
-
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(true));
-        // verify that both nodes are still in the cluster state but there is no master
-        assertThat(state.nodes().getSize(), equalTo(2));
-        assertThat(state.nodes().getMasterNode(), equalTo(null));
-
-        logger.info("--> starting the previous master node again...");
-        node2Name = internalCluster().startNode(Settings.builder().put(settings).put(masterDataPathSettings).build());
-
-        clusterHealthResponse = client().admin()
-            .cluster()
-            .prepareHealth()
-            .setWaitForEvents(Priority.LANGUID)
-            .setWaitForYellowStatus()
-            .setWaitForNodes("2")
-            .execute()
-            .actionGet();
-        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
-
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-
-        state = client().admin().cluster().prepareState().execute().actionGet().getState();
-        assertThat(state.nodes().getSize(), equalTo(2));
-        assertThat(state.metadata().indices().containsKey("test"), equalTo(true));
-
-        ensureGreen();
-
-        logger.info("--> verify we get the data back after cluster reform");
-        for (int i = 0; i < 10; i++) {
-            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
-        }
-
-        logger.info("--> clearing voting config exclusions");
-        ClearVotingConfigExclusionsRequest clearRequest = new ClearVotingConfigExclusionsRequest();
-        clearRequest.setWaitForRemoval(false);
-        client().execute(ClearVotingConfigExclusionsAction.INSTANCE, clearRequest).get();
-
-        masterNode = internalCluster().getMasterName();
-        otherNode = node1Name.equals(masterNode) ? node2Name : node1Name;
-        logger.info("--> add voting config exclusion for master node, to be sure it's not elected");
-        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(masterNode)).get();
-        logger.info("--> stop non-master node, no master block should appear");
-        Settings otherNodeDataPathSettings = internalCluster().dataPathSettings(otherNode);
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(otherNode));
-
-        assertBusy(() -> {
-            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-            assertThat(state1.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(true));
-        });
-
-        logger.info("--> starting the previous master node again...");
-        internalCluster().startNode(Settings.builder().put(settings).put(otherNodeDataPathSettings).build());
-
-        ensureGreen();
-        clusterHealthResponse = client().admin()
-            .cluster()
-            .prepareHealth()
-            .setWaitForEvents(Priority.LANGUID)
-            .setWaitForNodes("2")
-            .setWaitForGreenStatus()
-            .execute()
-            .actionGet();
-        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
-
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-        state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertThat(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(false));
-
-        state = client().admin().cluster().prepareState().execute().actionGet().getState();
-        assertThat(state.nodes().getSize(), equalTo(2));
-        assertThat(state.metadata().indices().containsKey("test"), equalTo(true));
-
-        logger.info("Running Cluster Health");
-        ensureGreen();
-
-        logger.info("--> verify we the data back");
-        for (int i = 0; i < 10; i++) {
-            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
-        }
-    }
-
-    public void testThreeNodesNoMasterBlock() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
-
-        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
-
-        logger.info("--> start first 2 nodes");
-        internalCluster().startNodes(2, settings);
-
-        ClusterState state;
-
-        assertBusy(() -> {
-            for (Client client : clients()) {
-                ClusterState state1 = client.admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-                assertThat(state1.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(true));
-            }
-        });
-
-        logger.info("--> start one more node");
-        internalCluster().startNode(settings);
-
-        ensureGreen();
-        ClusterHealthResponse clusterHealthResponse = client().admin()
-            .cluster()
-            .prepareHealth()
-            .setWaitForEvents(Priority.LANGUID)
-            .setWaitForNodes("3")
-            .execute()
-            .actionGet();
-        assertThat(clusterHealthResponse.isTimedOut(), equalTo(false));
-
-        state = client().admin().cluster().prepareState().execute().actionGet().getState();
-        assertThat(state.nodes().getSize(), equalTo(3));
-
-        createIndex("test");
-        NumShards numShards = getNumShards("test");
-        logger.info("--> indexing some data");
-        for (int i = 0; i < 100; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").execute().actionGet();
-        }
-        ensureGreen();
-        // make sure that all shards recovered before trying to flush
-        assertThat(
-            client().admin()
-                .cluster()
-                .prepareHealth("test")
-                .setWaitForActiveShards(numShards.totalNumShards)
-                .execute()
-                .actionGet()
-                .isTimedOut(),
-            equalTo(false)
-        );
-        // flush for simpler debugging
-        client().admin().indices().prepareFlush().execute().actionGet();
-
-        refresh();
-        logger.info("--> verify we get the data back");
-        for (int i = 0; i < 10; i++) {
-            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
-        }
-
-        List<String> nonMasterNodes = new ArrayList<>(
-            Sets.difference(Sets.newHashSet(internalCluster().getNodeNames()), Collections.singleton(internalCluster().getMasterName()))
-        );
-        Settings nonMasterDataPathSettings1 = internalCluster().dataPathSettings(nonMasterNodes.get(0));
-        Settings nonMasterDataPathSettings2 = internalCluster().dataPathSettings(nonMasterNodes.get(1));
-        internalCluster().stopRandomNonMasterNode();
-        internalCluster().stopRandomNonMasterNode();
-
-        logger.info("--> verify that there is no master anymore on remaining node");
-        // spin here to wait till the state is set
-        assertBusy(() -> {
-            ClusterState st = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-            assertThat(st.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID), equalTo(true));
-        });
-
-        logger.info("--> start back the 2 nodes ");
-        internalCluster().startNodes(nonMasterDataPathSettings1, nonMasterDataPathSettings2);
-
-        internalCluster().validateClusterFormed();
-        ensureGreen();
-
-        state = client().admin().cluster().prepareState().execute().actionGet().getState();
-        assertThat(state.nodes().getSize(), equalTo(3));
-
-        logger.info("--> verify we the data back");
-        for (int i = 0; i < 10; i++) {
-            assertHitCount(client().prepareSearch().setSize(0).setQuery(QueryBuilders.matchAllQuery()).execute().actionGet(), 100);
-        }
-    }
-
-    public void testCannotCommitStateThreeNodes() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
-
-        Settings settings = Settings.builder().put("discovery.initial_state_timeout", "500ms").build();
-
-        internalCluster().startNodes(3, settings);
-        ensureStableCluster(3);
-
-        final String master = internalCluster().getMasterName();
-        Set<String> otherNodes = new HashSet<>(Arrays.asList(internalCluster().getNodeNames()));
-        otherNodes.remove(master);
-        NetworkDisruption partition = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
-        internalCluster().setDisruptionScheme(partition);
-
-        final CountDownLatch latch = new CountDownLatch(1);
-        final AtomicReference<Exception> failure = new AtomicReference<>();
-        logger.debug("--> submitting for cluster state to be rejected");
-        final ClusterService masterClusterService = internalCluster().clusterService(master);
-        masterClusterService.submitStateUpdateTask("test", new ClusterStateUpdateTask() {
-            @Override
-            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
-                latch.countDown();
-            }
-
-            @Override
-            public ClusterState execute(ClusterState currentState) throws Exception {
-                logger.debug("--> starting the disruption, preventing cluster state publishing");
-                partition.startDisrupting();
-                Metadata.Builder metadata = Metadata.builder(currentState.metadata())
-                    .persistentSettings(
-                        Settings.builder().put(currentState.metadata().persistentSettings()).put("_SHOULD_NOT_BE_THERE_", true).build()
-                    );
-                return ClusterState.builder(currentState).metadata(metadata).build();
-            }
-
-            @Override
-            public void onFailure(String source, Exception e) {
-                failure.set(e);
-                latch.countDown();
-            }
-        });
-
-        logger.debug("--> waiting for cluster state to be processed/rejected");
-        latch.await();
-
-        assertThat(failure.get(), instanceOf(FailedToCommitClusterStateException.class));
-
-        logger.debug("--> check that there is no master in minor partition");
-        assertBusy(() -> assertThat(masterClusterService.state().nodes().getMasterNode(), nullValue()));
-
-        // let major partition to elect new master, to ensure that old master is not elected once partition is restored,
-        // otherwise persistent setting (which is a part of accepted state on old master) will be propagated to other nodes
-        logger.debug("--> wait for master to be elected in major partition");
-        assertBusy(() -> {
-            DiscoveryNode masterNode = internalCluster().client(randomFrom(otherNodes))
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode();
-            assertThat(masterNode, notNullValue());
-            assertThat(masterNode.getName(), not(equalTo(master)));
-        });
-
-        partition.stopDisrupting();
-
-        logger.debug("--> waiting for cluster to heal");
-        assertNoTimeout(client().admin().cluster().prepareHealth().setWaitForNodes("3").setWaitForEvents(Priority.LANGUID));
-
-        for (String node : internalCluster().getNodeNames()) {
-            Settings nodeSetting = internalCluster().clusterService(node).state().metadata().settings();
-            assertThat(
-                node + " processed the cluster state despite of a min master node violation",
-                nodeSetting.get("_SHOULD_NOT_BE_THERE_"),
-                nullValue()
-            );
-        }
-
-    }
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/NoClusterManagerNodeIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/NoClusterManagerNodeIT.java
new file mode 100644
index 0000000000000..da500fa717202
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/NoClusterManagerNodeIT.java
@@ -0,0 +1,461 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.action.bulk.BulkRequestBuilder;
+import org.opensearch.action.get.GetResponse;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.support.AutoCreateIndex;
+import org.opensearch.client.Client;
+import org.opensearch.client.Requests;
+import org.opensearch.cluster.action.index.MappingUpdatedAction;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.disruption.NetworkDisruption.IsolateAllNodes;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertExists;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertRequestBuilderThrows;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+
+@ClusterScope(scope = Scope.TEST, numDataNodes = 0)
+public class NoClusterManagerNodeIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected int numberOfReplicas() {
+        return 2;
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Collections.singletonList(MockTransportService.TestPlugin.class);
+    }
+
+    public void testNoClusterManagerActions() throws Exception {
+        Settings settings = Settings.builder()
+            .put(AutoCreateIndex.AUTO_CREATE_INDEX_SETTING.getKey(), true)
+            .put(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all")
+            .build();
+
+        final TimeValue timeout = TimeValue.timeValueMillis(10);
+
+        final List<String> nodes = internalCluster().startNodes(3, settings);
+
+        createIndex("test");
+        client().admin().cluster().prepareHealth("test").setWaitForGreenStatus().execute().actionGet();
+
+        final NetworkDisruption disruptionScheme = new NetworkDisruption(
+            new IsolateAllNodes(new HashSet<>(nodes)),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(disruptionScheme);
+        disruptionScheme.startDisrupting();
+
+        final Client clientToClusterManagerlessNode = client();
+
+        assertBusy(() -> {
+            ClusterState state = clientToClusterManagerlessNode.admin()
+                .cluster()
+                .prepareState()
+                .setLocal(true)
+                .execute()
+                .actionGet()
+                .getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
+        });
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareGet("test", "1"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareGet("no_index", "1"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareMultiGet().add("test", "1"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareMultiGet().add("no_index", "1"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.admin().indices().prepareAnalyze("test", "this is a test"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.admin().indices().prepareAnalyze("no_index", "this is a test"),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareSearch("test").setSize(0),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        assertRequestBuilderThrows(
+            clientToClusterManagerlessNode.prepareSearch("no_index").setSize(0),
+            ClusterBlockException.class,
+            RestStatus.SERVICE_UNAVAILABLE
+        );
+
+        checkUpdateAction(
+            false,
+            timeout,
+            clientToClusterManagerlessNode.prepareUpdate("test", "1")
+                .setScript(new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, "test script", Collections.emptyMap()))
+                .setTimeout(timeout)
+        );
+
+        checkUpdateAction(
+            true,
+            timeout,
+            clientToClusterManagerlessNode.prepareUpdate("no_index", "1")
+                .setScript(new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, "test script", Collections.emptyMap()))
+                .setTimeout(timeout)
+        );
+
+        checkWriteAction(
+            clientToClusterManagerlessNode.prepareIndex("test")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+                .setTimeout(timeout)
+        );
+
+        checkWriteAction(
+            clientToClusterManagerlessNode.prepareIndex("no_index")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+                .setTimeout(timeout)
+        );
+
+        BulkRequestBuilder bulkRequestBuilder = clientToClusterManagerlessNode.prepareBulk();
+        bulkRequestBuilder.add(
+            clientToClusterManagerlessNode.prepareIndex("test")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+        );
+        bulkRequestBuilder.add(
+            clientToClusterManagerlessNode.prepareIndex("test")
+                .setId("2")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+        );
+        bulkRequestBuilder.setTimeout(timeout);
+        checkWriteAction(bulkRequestBuilder);
+
+        bulkRequestBuilder = clientToClusterManagerlessNode.prepareBulk();
+        bulkRequestBuilder.add(
+            clientToClusterManagerlessNode.prepareIndex("no_index")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+        );
+        bulkRequestBuilder.add(
+            clientToClusterManagerlessNode.prepareIndex("no_index")
+                .setId("2")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+        );
+        bulkRequestBuilder.setTimeout(timeout);
+        checkWriteAction(bulkRequestBuilder);
+
+        internalCluster().clearDisruptionScheme(true);
+    }
+
+    void checkUpdateAction(boolean autoCreateIndex, TimeValue timeout, ActionRequestBuilder<?, ?> builder) {
+        // we clean the metadata when loosing a cluster-manager, therefore all operations on indices will auto create it, if allowed
+        try {
+            builder.get();
+            fail("expected ClusterBlockException or ClusterManagerNotDiscoveredException");
+        } catch (ClusterBlockException | ClusterManagerNotDiscoveredException e) {
+            if (e instanceof ClusterManagerNotDiscoveredException) {
+                assertTrue(autoCreateIndex);
+            } else {
+                assertFalse(autoCreateIndex);
+            }
+            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
+        }
+    }
+
+    void checkWriteAction(ActionRequestBuilder<?, ?> builder) {
+        try {
+            builder.get();
+            fail("Expected ClusterBlockException");
+        } catch (ClusterBlockException e) {
+            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
+        }
+    }
+
+    public void testNoClusterManagerActionsWriteClusterManagerBlock() throws Exception {
+        Settings settings = Settings.builder()
+            .put(AutoCreateIndex.AUTO_CREATE_INDEX_SETTING.getKey(), false)
+            .put(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write")
+            .build();
+
+        final List<String> nodes = internalCluster().startNodes(3, settings);
+
+        prepareCreate("test1").setSettings(
+            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+        ).get();
+        prepareCreate("test2").setSettings(
+            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+        ).get();
+        client().admin().cluster().prepareHealth("_all").setWaitForGreenStatus().get();
+        client().prepareIndex("test1").setId("1").setSource("field", "value1").get();
+        client().prepareIndex("test2").setId("1").setSource("field", "value1").get();
+        refresh();
+
+        ensureSearchable("test1", "test2");
+
+        ClusterStateResponse clusterState = client().admin().cluster().prepareState().get();
+        logger.info("Cluster state:\n{}", clusterState.getState());
+
+        final NetworkDisruption disruptionScheme = new NetworkDisruption(
+            new IsolateAllNodes(new HashSet<>(nodes)),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(disruptionScheme);
+        disruptionScheme.startDisrupting();
+
+        final Client clientToClusterManagerlessNode = client();
+
+        assertBusy(() -> {
+            ClusterState state = clientToClusterManagerlessNode.admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
+        });
+
+        GetResponse getResponse = clientToClusterManagerlessNode.prepareGet("test1", "1").get();
+        assertExists(getResponse);
+
+        SearchResponse countResponse = clientToClusterManagerlessNode.prepareSearch("test1")
+            .setAllowPartialSearchResults(true)
+            .setSize(0)
+            .get();
+        assertHitCount(countResponse, 1L);
+
+        logger.info("--> here 3");
+        SearchResponse searchResponse = clientToClusterManagerlessNode.prepareSearch("test1").setAllowPartialSearchResults(true).get();
+        assertHitCount(searchResponse, 1L);
+
+        countResponse = clientToClusterManagerlessNode.prepareSearch("test2").setAllowPartialSearchResults(true).setSize(0).get();
+        assertThat(countResponse.getTotalShards(), equalTo(3));
+        assertThat(countResponse.getSuccessfulShards(), equalTo(1));
+
+        TimeValue timeout = TimeValue.timeValueMillis(200);
+        long now = System.currentTimeMillis();
+        try {
+            clientToClusterManagerlessNode.prepareUpdate("test1", "1")
+                .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
+                .setTimeout(timeout)
+                .get();
+            fail("Expected ClusterBlockException");
+        } catch (ClusterBlockException e) {
+            assertThat(System.currentTimeMillis() - now, greaterThan(timeout.millis() - 50));
+            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
+        } catch (Exception e) {
+            logger.info("unexpected", e);
+            throw e;
+        }
+
+        try {
+            clientToClusterManagerlessNode.prepareIndex("test1")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+                .setTimeout(timeout)
+                .get();
+            fail("Expected ClusterBlockException");
+        } catch (ClusterBlockException e) {
+            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
+        }
+
+        internalCluster().clearDisruptionScheme(true);
+    }
+
+    public void testNoClusterManagerActionsMetadataWriteClusterManagerBlock() throws Exception {
+        Settings settings = Settings.builder()
+            .put(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write")
+            .put(MappingUpdatedAction.INDICES_MAPPING_DYNAMIC_TIMEOUT_SETTING.getKey(), "100ms")
+            .build();
+
+        final List<String> nodes = internalCluster().startNodes(3, settings);
+
+        prepareCreate("test1").setSettings(
+            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+        ).get();
+        client().admin().cluster().prepareHealth("_all").setWaitForGreenStatus().get();
+        client().prepareIndex("test1").setId("1").setSource("field", "value1").get();
+        refresh();
+
+        ensureGreen("test1");
+
+        ClusterStateResponse clusterState = client().admin().cluster().prepareState().get();
+        logger.info("Cluster state:\n{}", clusterState.getState());
+
+        final List<String> nodesWithShards = clusterState.getState()
+            .routingTable()
+            .index("test1")
+            .shard(0)
+            .activeShards()
+            .stream()
+            .map(shardRouting -> shardRouting.currentNodeId())
+            .map(nodeId -> clusterState.getState().nodes().resolveNode(nodeId))
+            .map(DiscoveryNode::getName)
+            .collect(Collectors.toList());
+
+        client().execute(
+            AddVotingConfigExclusionsAction.INSTANCE,
+            new AddVotingConfigExclusionsRequest(nodesWithShards.toArray(new String[0]))
+        ).get();
+        ensureGreen("test1");
+
+        String partitionedNode = nodes.stream().filter(n -> nodesWithShards.contains(n) == false).findFirst().get();
+
+        final NetworkDisruption disruptionScheme = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(Collections.singleton(partitionedNode), new HashSet<>(nodesWithShards)),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(disruptionScheme);
+        disruptionScheme.startDisrupting();
+
+        assertBusy(() -> {
+            for (String node : nodesWithShards) {
+                ClusterState state = client(node).admin().cluster().prepareState().setLocal(true).get().getState();
+                assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
+            }
+        });
+
+        GetResponse getResponse = client(randomFrom(nodesWithShards)).prepareGet("test1", "1").get();
+        assertExists(getResponse);
+
+        expectThrows(Exception.class, () -> client(partitionedNode).prepareGet("test1", "1").get());
+
+        SearchResponse countResponse = client(randomFrom(nodesWithShards)).prepareSearch("test1")
+            .setAllowPartialSearchResults(true)
+            .setSize(0)
+            .get();
+        assertHitCount(countResponse, 1L);
+
+        expectThrows(
+            Exception.class,
+            () -> client(partitionedNode).prepareSearch("test1").setAllowPartialSearchResults(true).setSize(0).get()
+        );
+
+        TimeValue timeout = TimeValue.timeValueMillis(200);
+        client(randomFrom(nodesWithShards)).prepareUpdate("test1", "1")
+            .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
+            .setTimeout(timeout)
+            .get();
+
+        expectThrows(
+            Exception.class,
+            () -> client(partitionedNode).prepareUpdate("test1", "1")
+                .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
+                .setTimeout(timeout)
+                .get()
+        );
+
+        client(randomFrom(nodesWithShards)).prepareIndex("test1")
+            .setId("1")
+            .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+            .setTimeout(timeout)
+            .get();
+
+        // dynamic mapping updates fail
+        expectThrows(
+            ClusterManagerNotDiscoveredException.class,
+            () -> client(randomFrom(nodesWithShards)).prepareIndex("test1")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().field("new_field", "value").endObject())
+                .setTimeout(timeout)
+                .get()
+        );
+
+        // dynamic index creation fails
+        expectThrows(
+            ClusterManagerNotDiscoveredException.class,
+            () -> client(randomFrom(nodesWithShards)).prepareIndex("test2")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+                .setTimeout(timeout)
+                .get()
+        );
+
+        expectThrows(
+            Exception.class,
+            () -> client(partitionedNode).prepareIndex("test1")
+                .setId("1")
+                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
+                .setTimeout(timeout)
+                .get()
+        );
+
+        internalCluster().clearDisruptionScheme(true);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/NoMasterNodeIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/NoMasterNodeIT.java
deleted file mode 100644
index 5226eed2b6610..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/NoMasterNodeIT.java
+++ /dev/null
@@ -1,444 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.cluster;
-
-import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
-import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
-import org.opensearch.action.bulk.BulkRequestBuilder;
-import org.opensearch.action.get.GetResponse;
-import org.opensearch.action.search.SearchResponse;
-import org.opensearch.action.support.AutoCreateIndex;
-import org.opensearch.client.Client;
-import org.opensearch.client.Requests;
-import org.opensearch.cluster.action.index.MappingUpdatedAction;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.discovery.MasterNotDiscoveredException;
-import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.script.Script;
-import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.disruption.NetworkDisruption;
-import org.opensearch.test.disruption.NetworkDisruption.IsolateAllNodes;
-import org.opensearch.test.transport.MockTransportService;
-
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.stream.Collectors;
-
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertExists;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertRequestBuilderThrows;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThan;
-
-@ClusterScope(scope = Scope.TEST, numDataNodes = 0)
-public class NoMasterNodeIT extends OpenSearchIntegTestCase {
-
-    @Override
-    protected int numberOfReplicas() {
-        return 2;
-    }
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Collections.singletonList(MockTransportService.TestPlugin.class);
-    }
-
-    public void testNoMasterActions() throws Exception {
-        Settings settings = Settings.builder()
-            .put(AutoCreateIndex.AUTO_CREATE_INDEX_SETTING.getKey(), true)
-            .put(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all")
-            .build();
-
-        final TimeValue timeout = TimeValue.timeValueMillis(10);
-
-        final List<String> nodes = internalCluster().startNodes(3, settings);
-
-        createIndex("test");
-        client().admin().cluster().prepareHealth("test").setWaitForGreenStatus().execute().actionGet();
-
-        final NetworkDisruption disruptionScheme = new NetworkDisruption(
-            new IsolateAllNodes(new HashSet<>(nodes)),
-            NetworkDisruption.DISCONNECT
-        );
-        internalCluster().setDisruptionScheme(disruptionScheme);
-        disruptionScheme.startDisrupting();
-
-        final Client clientToMasterlessNode = client();
-
-        assertBusy(() -> {
-            ClusterState state = clientToMasterlessNode.admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-            assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
-        });
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareGet("test", "1"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareGet("no_index", "1"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareMultiGet().add("test", "1"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareMultiGet().add("no_index", "1"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.admin().indices().prepareAnalyze("test", "this is a test"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.admin().indices().prepareAnalyze("no_index", "this is a test"),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareSearch("test").setSize(0),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        assertRequestBuilderThrows(
-            clientToMasterlessNode.prepareSearch("no_index").setSize(0),
-            ClusterBlockException.class,
-            RestStatus.SERVICE_UNAVAILABLE
-        );
-
-        checkUpdateAction(
-            false,
-            timeout,
-            clientToMasterlessNode.prepareUpdate("test", "1")
-                .setScript(new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, "test script", Collections.emptyMap()))
-                .setTimeout(timeout)
-        );
-
-        checkUpdateAction(
-            true,
-            timeout,
-            clientToMasterlessNode.prepareUpdate("no_index", "1")
-                .setScript(new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, "test script", Collections.emptyMap()))
-                .setTimeout(timeout)
-        );
-
-        checkWriteAction(
-            clientToMasterlessNode.prepareIndex("test")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-                .setTimeout(timeout)
-        );
-
-        checkWriteAction(
-            clientToMasterlessNode.prepareIndex("no_index")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-                .setTimeout(timeout)
-        );
-
-        BulkRequestBuilder bulkRequestBuilder = clientToMasterlessNode.prepareBulk();
-        bulkRequestBuilder.add(
-            clientToMasterlessNode.prepareIndex("test").setId("1").setSource(XContentFactory.jsonBuilder().startObject().endObject())
-        );
-        bulkRequestBuilder.add(
-            clientToMasterlessNode.prepareIndex("test").setId("2").setSource(XContentFactory.jsonBuilder().startObject().endObject())
-        );
-        bulkRequestBuilder.setTimeout(timeout);
-        checkWriteAction(bulkRequestBuilder);
-
-        bulkRequestBuilder = clientToMasterlessNode.prepareBulk();
-        bulkRequestBuilder.add(
-            clientToMasterlessNode.prepareIndex("no_index").setId("1").setSource(XContentFactory.jsonBuilder().startObject().endObject())
-        );
-        bulkRequestBuilder.add(
-            clientToMasterlessNode.prepareIndex("no_index").setId("2").setSource(XContentFactory.jsonBuilder().startObject().endObject())
-        );
-        bulkRequestBuilder.setTimeout(timeout);
-        checkWriteAction(bulkRequestBuilder);
-
-        internalCluster().clearDisruptionScheme(true);
-    }
-
-    void checkUpdateAction(boolean autoCreateIndex, TimeValue timeout, ActionRequestBuilder<?, ?> builder) {
-        // we clean the metadata when loosing a master, therefore all operations on indices will auto create it, if allowed
-        try {
-            builder.get();
-            fail("expected ClusterBlockException or MasterNotDiscoveredException");
-        } catch (ClusterBlockException | MasterNotDiscoveredException e) {
-            if (e instanceof MasterNotDiscoveredException) {
-                assertTrue(autoCreateIndex);
-            } else {
-                assertFalse(autoCreateIndex);
-            }
-            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
-        }
-    }
-
-    void checkWriteAction(ActionRequestBuilder<?, ?> builder) {
-        try {
-            builder.get();
-            fail("Expected ClusterBlockException");
-        } catch (ClusterBlockException e) {
-            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
-        }
-    }
-
-    public void testNoMasterActionsWriteMasterBlock() throws Exception {
-        Settings settings = Settings.builder()
-            .put(AutoCreateIndex.AUTO_CREATE_INDEX_SETTING.getKey(), false)
-            .put(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write")
-            .build();
-
-        final List<String> nodes = internalCluster().startNodes(3, settings);
-
-        prepareCreate("test1").setSettings(
-            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
-        ).get();
-        prepareCreate("test2").setSettings(
-            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-        ).get();
-        client().admin().cluster().prepareHealth("_all").setWaitForGreenStatus().get();
-        client().prepareIndex("test1").setId("1").setSource("field", "value1").get();
-        client().prepareIndex("test2").setId("1").setSource("field", "value1").get();
-        refresh();
-
-        ensureSearchable("test1", "test2");
-
-        ClusterStateResponse clusterState = client().admin().cluster().prepareState().get();
-        logger.info("Cluster state:\n{}", clusterState.getState());
-
-        final NetworkDisruption disruptionScheme = new NetworkDisruption(
-            new IsolateAllNodes(new HashSet<>(nodes)),
-            NetworkDisruption.DISCONNECT
-        );
-        internalCluster().setDisruptionScheme(disruptionScheme);
-        disruptionScheme.startDisrupting();
-
-        final Client clientToMasterlessNode = client();
-
-        assertBusy(() -> {
-            ClusterState state = clientToMasterlessNode.admin().cluster().prepareState().setLocal(true).get().getState();
-            assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
-        });
-
-        GetResponse getResponse = clientToMasterlessNode.prepareGet("test1", "1").get();
-        assertExists(getResponse);
-
-        SearchResponse countResponse = clientToMasterlessNode.prepareSearch("test1").setAllowPartialSearchResults(true).setSize(0).get();
-        assertHitCount(countResponse, 1L);
-
-        logger.info("--> here 3");
-        SearchResponse searchResponse = clientToMasterlessNode.prepareSearch("test1").setAllowPartialSearchResults(true).get();
-        assertHitCount(searchResponse, 1L);
-
-        countResponse = clientToMasterlessNode.prepareSearch("test2").setAllowPartialSearchResults(true).setSize(0).get();
-        assertThat(countResponse.getTotalShards(), equalTo(3));
-        assertThat(countResponse.getSuccessfulShards(), equalTo(1));
-
-        TimeValue timeout = TimeValue.timeValueMillis(200);
-        long now = System.currentTimeMillis();
-        try {
-            clientToMasterlessNode.prepareUpdate("test1", "1")
-                .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
-                .setTimeout(timeout)
-                .get();
-            fail("Expected ClusterBlockException");
-        } catch (ClusterBlockException e) {
-            assertThat(System.currentTimeMillis() - now, greaterThan(timeout.millis() - 50));
-            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
-        } catch (Exception e) {
-            logger.info("unexpected", e);
-            throw e;
-        }
-
-        try {
-            clientToMasterlessNode.prepareIndex("test1")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-                .setTimeout(timeout)
-                .get();
-            fail("Expected ClusterBlockException");
-        } catch (ClusterBlockException e) {
-            assertThat(e.status(), equalTo(RestStatus.SERVICE_UNAVAILABLE));
-        }
-
-        internalCluster().clearDisruptionScheme(true);
-    }
-
-    public void testNoMasterActionsMetadataWriteMasterBlock() throws Exception {
-        Settings settings = Settings.builder()
-            .put(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write")
-            .put(MappingUpdatedAction.INDICES_MAPPING_DYNAMIC_TIMEOUT_SETTING.getKey(), "100ms")
-            .build();
-
-        final List<String> nodes = internalCluster().startNodes(3, settings);
-
-        prepareCreate("test1").setSettings(
-            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
-        ).get();
-        client().admin().cluster().prepareHealth("_all").setWaitForGreenStatus().get();
-        client().prepareIndex("test1").setId("1").setSource("field", "value1").get();
-        refresh();
-
-        ensureGreen("test1");
-
-        ClusterStateResponse clusterState = client().admin().cluster().prepareState().get();
-        logger.info("Cluster state:\n{}", clusterState.getState());
-
-        final List<String> nodesWithShards = clusterState.getState()
-            .routingTable()
-            .index("test1")
-            .shard(0)
-            .activeShards()
-            .stream()
-            .map(shardRouting -> shardRouting.currentNodeId())
-            .map(nodeId -> clusterState.getState().nodes().resolveNode(nodeId))
-            .map(DiscoveryNode::getName)
-            .collect(Collectors.toList());
-
-        client().execute(
-            AddVotingConfigExclusionsAction.INSTANCE,
-            new AddVotingConfigExclusionsRequest(nodesWithShards.toArray(new String[0]))
-        ).get();
-        ensureGreen("test1");
-
-        String partitionedNode = nodes.stream().filter(n -> nodesWithShards.contains(n) == false).findFirst().get();
-
-        final NetworkDisruption disruptionScheme = new NetworkDisruption(
-            new NetworkDisruption.TwoPartitions(Collections.singleton(partitionedNode), new HashSet<>(nodesWithShards)),
-            NetworkDisruption.DISCONNECT
-        );
-        internalCluster().setDisruptionScheme(disruptionScheme);
-        disruptionScheme.startDisrupting();
-
-        assertBusy(() -> {
-            for (String node : nodesWithShards) {
-                ClusterState state = client(node).admin().cluster().prepareState().setLocal(true).get().getState();
-                assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
-            }
-        });
-
-        GetResponse getResponse = client(randomFrom(nodesWithShards)).prepareGet("test1", "1").get();
-        assertExists(getResponse);
-
-        expectThrows(Exception.class, () -> client(partitionedNode).prepareGet("test1", "1").get());
-
-        SearchResponse countResponse = client(randomFrom(nodesWithShards)).prepareSearch("test1")
-            .setAllowPartialSearchResults(true)
-            .setSize(0)
-            .get();
-        assertHitCount(countResponse, 1L);
-
-        expectThrows(
-            Exception.class,
-            () -> client(partitionedNode).prepareSearch("test1").setAllowPartialSearchResults(true).setSize(0).get()
-        );
-
-        TimeValue timeout = TimeValue.timeValueMillis(200);
-        client(randomFrom(nodesWithShards)).prepareUpdate("test1", "1")
-            .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
-            .setTimeout(timeout)
-            .get();
-
-        expectThrows(
-            Exception.class,
-            () -> client(partitionedNode).prepareUpdate("test1", "1")
-                .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
-                .setTimeout(timeout)
-                .get()
-        );
-
-        client(randomFrom(nodesWithShards)).prepareIndex("test1")
-            .setId("1")
-            .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-            .setTimeout(timeout)
-            .get();
-
-        // dynamic mapping updates fail
-        expectThrows(
-            MasterNotDiscoveredException.class,
-            () -> client(randomFrom(nodesWithShards)).prepareIndex("test1")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().field("new_field", "value").endObject())
-                .setTimeout(timeout)
-                .get()
-        );
-
-        // dynamic index creation fails
-        expectThrows(
-            MasterNotDiscoveredException.class,
-            () -> client(randomFrom(nodesWithShards)).prepareIndex("test2")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-                .setTimeout(timeout)
-                .get()
-        );
-
-        expectThrows(
-            Exception.class,
-            () -> client(partitionedNode).prepareIndex("test1")
-                .setId("1")
-                .setSource(XContentFactory.jsonBuilder().startObject().endObject())
-                .setTimeout(timeout)
-                .get()
-        );
-
-        internalCluster().clearDisruptionScheme(true);
-    }
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleClusterStateIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleClusterStateIT.java
index 19f7b0b4c630c..f0337e9c0c84c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleClusterStateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleClusterStateIT.java
@@ -45,17 +45,16 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexNotFoundException;
@@ -65,10 +64,8 @@
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.script.ScriptService;
 import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.hamcrest.CollectionAssertions;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.watcher.ResourceWatcherService;
-
 import org.junit.Before;
 
 import java.io.IOException;
@@ -76,6 +73,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Supplier;
 
@@ -85,6 +83,7 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.is;
 
 /**
@@ -238,14 +237,14 @@ private void testFilteringByIndexWorks(String[] indices, String[] expected) {
             .setIndices(indices)
             .get();
 
-        ImmutableOpenMap<String, IndexMetadata> metadata = clusterState.getState().getMetadata().indices();
+        final Map<String, IndexMetadata> metadata = clusterState.getState().getMetadata().indices();
         assertThat(metadata.size(), is(expected.length));
 
         RoutingTable routingTable = clusterState.getState().getRoutingTable();
         assertThat(routingTable.indicesRouting().size(), is(expected.length));
 
-        for (String expectedIndex : expected) {
-            assertThat(metadata, CollectionAssertions.hasKey(expectedIndex));
+        for (final String expectedIndex : expected) {
+            assertThat(metadata, hasKey(expectedIndex));
             assertThat(routingTable.hasIndex(expectedIndex), is(true));
         }
     }
@@ -286,7 +285,12 @@ public void testLargeClusterStatePublishing() throws Exception {
                 .get()
         );
         ensureGreen(); // wait for green state, so its both green, and there are no more pending events
-        MappingMetadata masterMappingMetadata = client().admin().indices().prepareGetMappings("test").get().getMappings().get("test");
+        MappingMetadata clusterManagerMappingMetadata = client().admin()
+            .indices()
+            .prepareGetMappings("test")
+            .get()
+            .getMappings()
+            .get("test");
         for (Client client : clients()) {
             MappingMetadata mappingMetadata = client.admin()
                 .indices()
@@ -295,8 +299,8 @@ public void testLargeClusterStatePublishing() throws Exception {
                 .get()
                 .getMappings()
                 .get("test");
-            assertThat(mappingMetadata.source().string(), equalTo(masterMappingMetadata.source().string()));
-            assertThat(mappingMetadata, equalTo(masterMappingMetadata));
+            assertThat(mappingMetadata.source().string(), equalTo(clusterManagerMappingMetadata.source().string()));
+            assertThat(mappingMetadata, equalTo(clusterManagerMappingMetadata));
         }
     }
 
@@ -468,7 +472,7 @@ public Collection<Object> createComponents(
                     return;
                 }
 
-                if (state.nodes().isLocalNodeElectedMaster()) {
+                if (state.nodes().isLocalNodeElectedClusterManager()) {
                     if (state.custom("test") == null) {
                         if (installed.compareAndSet(false, true)) {
                             clusterService.submitStateUpdateTask("install-metadata-custom", new ClusterStateUpdateTask(Priority.URGENT) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleDataNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleDataNodesIT.java
index d7adf57593953..4f7fda6b94e36 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleDataNodesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/SimpleDataNodesIT.java
@@ -41,7 +41,7 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
@@ -50,7 +50,6 @@
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 import static org.opensearch.test.NodeRoles.dataNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-
 import static org.hamcrest.Matchers.equalTo;
 
 @ClusterScope(scope = Scope.TEST, numDataNodes = 0)
@@ -62,7 +61,7 @@ public void testIndexingBeforeAndAfterDataNodesStart() {
         internalCluster().startNode(nonDataNode());
         client().admin().indices().create(createIndexRequest("test").waitForActiveShards(ActiveShardCount.NONE)).actionGet();
         try {
-            client().index(Requests.indexRequest("test").id("1").source(SOURCE, XContentType.JSON).timeout(timeValueSeconds(1)))
+            client().index(Requests.indexRequest("test").id("1").source(SOURCE, MediaTypeRegistry.JSON).timeout(timeValueSeconds(1)))
                 .actionGet();
             fail("no allocation should happen");
         } catch (UnavailableShardsException e) {
@@ -85,7 +84,7 @@ public void testIndexingBeforeAndAfterDataNodesStart() {
 
         // still no shard should be allocated
         try {
-            client().index(Requests.indexRequest("test").id("1").source(SOURCE, XContentType.JSON).timeout(timeValueSeconds(1)))
+            client().index(Requests.indexRequest("test").id("1").source(SOURCE, MediaTypeRegistry.JSON).timeout(timeValueSeconds(1)))
                 .actionGet();
             fail("no allocation should happen");
         } catch (UnavailableShardsException e) {
@@ -107,7 +106,8 @@ public void testIndexingBeforeAndAfterDataNodesStart() {
             equalTo(false)
         );
 
-        IndexResponse indexResponse = client().index(Requests.indexRequest("test").id("1").source(SOURCE, XContentType.JSON)).actionGet();
+        IndexResponse indexResponse = client().index(Requests.indexRequest("test").id("1").source(SOURCE, MediaTypeRegistry.JSON))
+            .actionGet();
         assertThat(indexResponse.getId(), equalTo("1"));
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificClusterManagerNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificClusterManagerNodesIT.java
new file mode 100644
index 0000000000000..713873bb222e2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificClusterManagerNodesIT.java
@@ -0,0 +1,339 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.apache.lucene.search.join.ScoreMode;
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+
+import java.io.IOException;
+
+import static org.opensearch.test.NodeRoles.clusterManagerNode;
+import static org.opensearch.test.NodeRoles.dataOnlyNode;
+import static org.opensearch.test.NodeRoles.nonDataNode;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+
+@ClusterScope(scope = Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class SpecificClusterManagerNodesIT extends OpenSearchIntegTestCase {
+
+    public void testSimpleOnlyClusterManagerNodeElection() throws IOException {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        logger.info("--> start data node / non cluster-manager node");
+        internalCluster().startNode(Settings.builder().put(dataOnlyNode()).put("discovery.initial_state_timeout", "1s"));
+        try {
+            assertThat(
+                client().admin()
+                    .cluster()
+                    .prepareState()
+                    .setClusterManagerNodeTimeout("100ms")
+                    .execute()
+                    .actionGet()
+                    .getState()
+                    .nodes()
+                    .getClusterManagerNodeId(),
+                nullValue()
+            );
+            fail("should not be able to find cluster-manager");
+        } catch (ClusterManagerNotDiscoveredException e) {
+            // all is well, no cluster-manager elected
+        }
+        logger.info("--> start cluster-manager node");
+        final String clusterManagerNodeName = internalCluster().startClusterManagerOnlyNode();
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+        assertThat(
+            internalCluster().clusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+
+        logger.info("--> stop cluster-manager node");
+        Settings clusterManagerDataPathSettings = internalCluster().dataPathSettings(internalCluster().getClusterManagerName());
+        internalCluster().stopCurrentClusterManagerNode();
+
+        try {
+            assertThat(
+                client().admin()
+                    .cluster()
+                    .prepareState()
+                    .setClusterManagerNodeTimeout("100ms")
+                    .execute()
+                    .actionGet()
+                    .getState()
+                    .nodes()
+                    .getClusterManagerNodeId(),
+                nullValue()
+            );
+            fail("should not be able to find cluster-manager");
+        } catch (ClusterManagerNotDiscoveredException e) {
+            // all is well, no cluster-manager elected
+        }
+
+        logger.info("--> start previous cluster-manager node again");
+        final String nextClusterManagerEligibleNodeName = internalCluster().startNode(
+            Settings.builder().put(nonDataNode(clusterManagerNode())).put(clusterManagerDataPathSettings)
+        );
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(nextClusterManagerEligibleNodeName)
+        );
+        assertThat(
+            internalCluster().clusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(nextClusterManagerEligibleNodeName)
+        );
+    }
+
+    public void testElectOnlyBetweenClusterManagerNodes() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        logger.info("--> start data node / non cluster-manager node");
+        internalCluster().startNode(Settings.builder().put(dataOnlyNode()).put("discovery.initial_state_timeout", "1s"));
+        try {
+            assertThat(
+                client().admin()
+                    .cluster()
+                    .prepareState()
+                    .setClusterManagerNodeTimeout("100ms")
+                    .execute()
+                    .actionGet()
+                    .getState()
+                    .nodes()
+                    .getClusterManagerNodeId(),
+                nullValue()
+            );
+            fail("should not be able to find cluster-manager");
+        } catch (ClusterManagerNotDiscoveredException e) {
+            // all is well, no cluster-manager elected
+        }
+        logger.info("--> start cluster-manager node (1)");
+        final String clusterManagerNodeName = internalCluster().startClusterManagerOnlyNode();
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+        assertThat(
+            internalCluster().clusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+
+        logger.info("--> start cluster-manager node (2)");
+        final String nextClusterManagerEligableNodeName = internalCluster().startClusterManagerOnlyNode();
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+        assertThat(
+            internalCluster().clusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(clusterManagerNodeName)
+        );
+
+        logger.info("--> closing cluster-manager node (1)");
+        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(clusterManagerNodeName)).get();
+        // removing the cluster-manager from the voting configuration immediately triggers the cluster-manager to step down
+        assertBusy(() -> {
+            assertThat(
+                internalCluster().nonClusterManagerClient()
+                    .admin()
+                    .cluster()
+                    .prepareState()
+                    .execute()
+                    .actionGet()
+                    .getState()
+                    .nodes()
+                    .getClusterManagerNode()
+                    .getName(),
+                equalTo(nextClusterManagerEligableNodeName)
+            );
+            assertThat(
+                internalCluster().clusterManagerClient()
+                    .admin()
+                    .cluster()
+                    .prepareState()
+                    .execute()
+                    .actionGet()
+                    .getState()
+                    .nodes()
+                    .getClusterManagerNode()
+                    .getName(),
+                equalTo(nextClusterManagerEligableNodeName)
+            );
+        });
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(clusterManagerNodeName));
+        assertThat(
+            internalCluster().nonClusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(nextClusterManagerEligableNodeName)
+        );
+        assertThat(
+            internalCluster().clusterManagerClient()
+                .admin()
+                .cluster()
+                .prepareState()
+                .execute()
+                .actionGet()
+                .getState()
+                .nodes()
+                .getClusterManagerNode()
+                .getName(),
+            equalTo(nextClusterManagerEligableNodeName)
+        );
+    }
+
+    public void testAliasFilterValidation() {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        logger.info("--> start cluster-manager node / non data");
+        internalCluster().startClusterManagerOnlyNode();
+
+        logger.info("--> start data node / non cluster-manager node");
+        internalCluster().startDataOnlyNode();
+
+        assertAcked(
+            prepareCreate("test").setMapping(
+                "{\"properties\" : {\"table_a\" : { \"type\" : \"nested\", "
+                    + "\"properties\" : {\"field_a\" : { \"type\" : \"keyword\" },\"field_b\" :{ \"type\" : \"keyword\" }}}}}"
+            )
+        );
+        client().admin()
+            .indices()
+            .prepareAliases()
+            .addAlias(
+                "test",
+                "a_test",
+                QueryBuilders.nestedQuery("table_a", QueryBuilders.termQuery("table_a.field_b", "y"), ScoreMode.Avg)
+            )
+            .get();
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificMasterNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificMasterNodesIT.java
deleted file mode 100644
index fc193163f75cc..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/SpecificMasterNodesIT.java
+++ /dev/null
@@ -1,339 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.cluster;
-
-import org.apache.lucene.search.join.ScoreMode;
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
-import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.discovery.MasterNotDiscoveredException;
-import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
-
-import java.io.IOException;
-
-import static org.opensearch.test.NodeRoles.dataOnlyNode;
-import static org.opensearch.test.NodeRoles.masterNode;
-import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.nullValue;
-
-@ClusterScope(scope = Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
-public class SpecificMasterNodesIT extends OpenSearchIntegTestCase {
-
-    public void testSimpleOnlyMasterNodeElection() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        logger.info("--> start data node / non master node");
-        internalCluster().startNode(Settings.builder().put(dataOnlyNode()).put("discovery.initial_state_timeout", "1s"));
-        try {
-            assertThat(
-                client().admin()
-                    .cluster()
-                    .prepareState()
-                    .setMasterNodeTimeout("100ms")
-                    .execute()
-                    .actionGet()
-                    .getState()
-                    .nodes()
-                    .getMasterNodeId(),
-                nullValue()
-            );
-            fail("should not be able to find master");
-        } catch (MasterNotDiscoveredException e) {
-            // all is well, no master elected
-        }
-        logger.info("--> start master node");
-        final String masterNodeName = internalCluster().startMasterOnlyNode();
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-        assertThat(
-            internalCluster().masterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-
-        logger.info("--> stop master node");
-        Settings masterDataPathSettings = internalCluster().dataPathSettings(internalCluster().getMasterName());
-        internalCluster().stopCurrentMasterNode();
-
-        try {
-            assertThat(
-                client().admin()
-                    .cluster()
-                    .prepareState()
-                    .setMasterNodeTimeout("100ms")
-                    .execute()
-                    .actionGet()
-                    .getState()
-                    .nodes()
-                    .getMasterNodeId(),
-                nullValue()
-            );
-            fail("should not be able to find master");
-        } catch (MasterNotDiscoveredException e) {
-            // all is well, no master elected
-        }
-
-        logger.info("--> start previous master node again");
-        final String nextMasterEligibleNodeName = internalCluster().startNode(
-            Settings.builder().put(nonDataNode(masterNode())).put(masterDataPathSettings)
-        );
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(nextMasterEligibleNodeName)
-        );
-        assertThat(
-            internalCluster().masterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(nextMasterEligibleNodeName)
-        );
-    }
-
-    public void testElectOnlyBetweenMasterNodes() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        logger.info("--> start data node / non master node");
-        internalCluster().startNode(Settings.builder().put(dataOnlyNode()).put("discovery.initial_state_timeout", "1s"));
-        try {
-            assertThat(
-                client().admin()
-                    .cluster()
-                    .prepareState()
-                    .setMasterNodeTimeout("100ms")
-                    .execute()
-                    .actionGet()
-                    .getState()
-                    .nodes()
-                    .getMasterNodeId(),
-                nullValue()
-            );
-            fail("should not be able to find master");
-        } catch (MasterNotDiscoveredException e) {
-            // all is well, no master elected
-        }
-        logger.info("--> start master node (1)");
-        final String masterNodeName = internalCluster().startMasterOnlyNode();
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-        assertThat(
-            internalCluster().masterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-
-        logger.info("--> start master node (2)");
-        final String nextMasterEligableNodeName = internalCluster().startMasterOnlyNode();
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-        assertThat(
-            internalCluster().masterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(masterNodeName)
-        );
-
-        logger.info("--> closing master node (1)");
-        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(masterNodeName)).get();
-        // removing the master from the voting configuration immediately triggers the master to step down
-        assertBusy(() -> {
-            assertThat(
-                internalCluster().nonMasterClient()
-                    .admin()
-                    .cluster()
-                    .prepareState()
-                    .execute()
-                    .actionGet()
-                    .getState()
-                    .nodes()
-                    .getMasterNode()
-                    .getName(),
-                equalTo(nextMasterEligableNodeName)
-            );
-            assertThat(
-                internalCluster().masterClient()
-                    .admin()
-                    .cluster()
-                    .prepareState()
-                    .execute()
-                    .actionGet()
-                    .getState()
-                    .nodes()
-                    .getMasterNode()
-                    .getName(),
-                equalTo(nextMasterEligableNodeName)
-            );
-        });
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(masterNodeName));
-        assertThat(
-            internalCluster().nonMasterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(nextMasterEligableNodeName)
-        );
-        assertThat(
-            internalCluster().masterClient()
-                .admin()
-                .cluster()
-                .prepareState()
-                .execute()
-                .actionGet()
-                .getState()
-                .nodes()
-                .getMasterNode()
-                .getName(),
-            equalTo(nextMasterEligableNodeName)
-        );
-    }
-
-    public void testAliasFilterValidation() {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        logger.info("--> start master node / non data");
-        internalCluster().startMasterOnlyNode();
-
-        logger.info("--> start data node / non master node");
-        internalCluster().startDataOnlyNode();
-
-        assertAcked(
-            prepareCreate("test").setMapping(
-                "{\"properties\" : {\"table_a\" : { \"type\" : \"nested\", "
-                    + "\"properties\" : {\"field_a\" : { \"type\" : \"keyword\" },\"field_b\" :{ \"type\" : \"keyword\" }}}}}"
-            )
-        );
-        client().admin()
-            .indices()
-            .prepareAliases()
-            .addAlias(
-                "test",
-                "a_test",
-                QueryBuilders.nestedQuery("table_a", QueryBuilders.termQuery("table_a.field_b", "y"), ScoreMode.Avg)
-            )
-            .get();
-    }
-
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/UpdateSettingsValidationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/UpdateSettingsValidationIT.java
index 66f22a4fdf1b3..4b830acddefdf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/UpdateSettingsValidationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/UpdateSettingsValidationIT.java
@@ -39,14 +39,14 @@
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
 
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
 import static org.hamcrest.Matchers.equalTo;
 
 @ClusterScope(scope = Scope.TEST, numDataNodes = 0)
 public class UpdateSettingsValidationIT extends OpenSearchIntegTestCase {
     public void testUpdateSettingsValidation() throws Exception {
-        internalCluster().startNodes(nonDataNode(), nonMasterNode(), nonMasterNode());
+        internalCluster().startNodes(nonDataNode(), nonClusterManagerNode(), nonClusterManagerNode());
 
         createIndex("test");
         NumShards test = getNumShards("test");
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/action/shard/ShardStateActionIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/action/shard/ShardStateActionIT.java
index dc1814c132d96..90eb3aa97a050 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/action/shard/ShardStateActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/action/shard/ShardStateActionIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.action.shard;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
 import org.opensearch.cluster.ClusterState;
@@ -40,6 +39,7 @@
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -119,10 +119,13 @@ public void testFollowupRerouteCanBeSetToHigherPriority() {
                 .setPersistentSettings(Settings.builder().put(ShardStateAction.FOLLOW_UP_REROUTE_PRIORITY_SETTING.getKey(), "urgent"))
         );
 
-        // ensure that the master always has a HIGH priority pending task
-        final AtomicBoolean stopSpammingMaster = new AtomicBoolean();
-        final ClusterService masterClusterService = internalCluster().getInstance(ClusterService.class, internalCluster().getMasterName());
-        masterClusterService.submitStateUpdateTask("spam", new ClusterStateUpdateTask(Priority.HIGH) {
+        // ensure that the cluster-manager always has a HIGH priority pending task
+        final AtomicBoolean stopSpammingClusterManager = new AtomicBoolean();
+        final ClusterService clusterManagerClusterService = internalCluster().getInstance(
+            ClusterService.class,
+            internalCluster().getClusterManagerName()
+        );
+        clusterManagerClusterService.submitStateUpdateTask("spam", new ClusterStateUpdateTask(Priority.HIGH) {
             @Override
             public ClusterState execute(ClusterState currentState) {
                 return currentState;
@@ -135,18 +138,18 @@ public void onFailure(String source, Exception e) {
 
             @Override
             public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
-                if (stopSpammingMaster.get() == false) {
-                    masterClusterService.submitStateUpdateTask("spam", this);
+                if (stopSpammingClusterManager.get() == false) {
+                    clusterManagerClusterService.submitStateUpdateTask("spam", this);
                 }
             }
         });
 
-        // even with the master under such pressure, all shards of the index can be assigned; in particular, after the primaries have
-        // started there's a follow-up reroute at a higher priority than the spam
+        // even with the cluster-manager under such pressure, all shards of the index can be assigned;
+        // in particular, after the primaries have started there's a follow-up reroute at a higher priority than the spam
         createIndex("test");
         assertFalse(client().admin().cluster().prepareHealth().setWaitForGreenStatus().get().isTimedOut());
 
-        stopSpammingMaster.set(true);
+        stopSpammingClusterManager.set(true);
         assertFalse(client().admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get().isTimedOut());
 
         assertAcked(
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/AwarenessAllocationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/AwarenessAllocationIT.java
index 224db09d99a99..5c8fc82a1c2b5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/AwarenessAllocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/AwarenessAllocationIT.java
@@ -32,27 +32,33 @@
 
 package org.opensearch.cluster.allocation;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata.State;
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
+import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.empty;
@@ -74,6 +80,12 @@ public void testSimpleAwareness() throws Exception {
         logger.info("--> starting 2 nodes on the same rack");
         internalCluster().startNodes(2, Settings.builder().put(commonSettings).put("node.attr.rack_id", "rack_1").build());
 
+        Settings settings = Settings.builder()
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), false)
+            .build();
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        updateSettingsRequest.persistentSettings(settings);
+
         createIndex("test1");
         createIndex("test2");
 
@@ -115,11 +127,11 @@ public void testSimpleAwareness() throws Exception {
             assertThat("Some indices not closed", notClosedIndices, empty());
 
             // verify that we have all the primaries on node3
-            ObjectIntHashMap<String> counts = new ObjectIntHashMap<>();
+            final Map<String, Integer> counts = new HashMap<>();
             for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
                 for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                     for (ShardRouting shardRouting : indexShardRoutingTable) {
-                        counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                        counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                     }
                 }
             }
@@ -171,12 +183,12 @@ public void testAwarenessZones() {
         assertThat(health.isTimedOut(), equalTo(false));
 
         ClusterState clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
-        ObjectIntHashMap<String> counts = new ObjectIntHashMap<>();
+        final Map<String, Integer> counts = new HashMap<>();
 
         for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
             for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                 for (ShardRouting shardRouting : indexShardRoutingTable) {
-                    counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                 }
             }
         }
@@ -221,12 +233,12 @@ public void testAwarenessZonesIncrementalNodes() {
             .actionGet();
         assertThat(health.isTimedOut(), equalTo(false));
         ClusterState clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
-        ObjectIntHashMap<String> counts = new ObjectIntHashMap<>();
+        Map<String, Integer> counts = new HashMap<>();
 
         for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
             for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                 for (ShardRouting shardRouting : indexShardRoutingTable) {
-                    counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                 }
             }
         }
@@ -261,12 +273,12 @@ public void testAwarenessZonesIncrementalNodes() {
         assertThat(health.isTimedOut(), equalTo(false));
         clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
 
-        counts = new ObjectIntHashMap<>();
+        counts = new HashMap<>();
 
         for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
             for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                 for (ShardRouting shardRouting : indexShardRoutingTable) {
-                    counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                 }
             }
         }
@@ -301,12 +313,12 @@ public void testAwarenessZonesIncrementalNodes() {
         assertThat(health.isTimedOut(), equalTo(false));
         clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
 
-        counts = new ObjectIntHashMap<>();
+        counts = new HashMap<>();
 
         for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
             for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                 for (ShardRouting shardRouting : indexShardRoutingTable) {
-                    counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                 }
             }
         }
@@ -336,12 +348,12 @@ public void testAwarenessZonesIncrementalNodes() {
         assertThat(health.isTimedOut(), equalTo(false));
         clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
 
-        counts = new ObjectIntHashMap<>();
+        counts = new HashMap<>();
 
         for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
             for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
                 for (ShardRouting shardRouting : indexShardRoutingTable) {
-                    counts.addTo(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1);
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
                 }
             }
         }
@@ -351,4 +363,140 @@ public void testAwarenessZonesIncrementalNodes() {
         assertThat(counts.get(B_1), equalTo(2));
         assertThat(counts.get(noZoneNode), equalTo(2));
     }
+
+    public void testThreeZoneOneReplicaWithForceZoneValueAndLoadAwareness() throws Exception {
+        int nodeCountPerAZ = 5;
+        int numOfShards = 30;
+        int numOfReplica = 1;
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.allocation.load_awareness.skew_factor", "0.0")
+            .put("cluster.routing.allocation.load_awareness.provisioned_capacity", Integer.toString(nodeCountPerAZ * 3))
+            .build();
+
+        logger.info("--> starting 15 nodes on zones 'a' & 'b' & 'c'");
+        List<String> nodes_in_zone_a = internalCluster().startNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        List<String> nodes_in_zone_b = internalCluster().startNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        List<String> nodes_in_zone_c = internalCluster().startNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        // Creating index with 30 primary and 1 replica
+        createIndex(
+            "test-1",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numOfReplica)
+                .build()
+        );
+
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setIndices("test-1")
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(nodeCountPerAZ * 3))
+            .setWaitForNoRelocatingShards(true)
+            .setWaitForNoInitializingShards(true)
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        ClusterState clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
+        final Map<String, Integer> counts = new HashMap<>();
+
+        for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
+            for (IndexShardRoutingTable indexShardRoutingTable : indexRoutingTable) {
+                for (ShardRouting shardRouting : indexShardRoutingTable) {
+                    counts.merge(clusterState.nodes().get(shardRouting.currentNodeId()).getName(), 1, Integer::sum);
+                }
+            }
+        }
+
+        assertThat(counts.size(), equalTo(nodeCountPerAZ * 3));
+        // All shards should be started
+        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(numOfShards * (numOfReplica + 1)));
+
+        // stopping half nodes in zone a
+        int nodesToStop = nodeCountPerAZ / 2;
+        List<Settings> nodeDataPathSettings = new ArrayList<>();
+        for (int i = 0; i < nodesToStop; i++) {
+            nodeDataPathSettings.add(internalCluster().dataPathSettings(nodes_in_zone_a.get(i)));
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodes_in_zone_a.get(i)));
+        }
+
+        client().admin().cluster().prepareReroute().setRetryFailed(true).get();
+        health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setIndices("test-1")
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes(Integer.toString(nodeCountPerAZ * 3 - nodesToStop))
+            .setWaitForNoRelocatingShards(true)
+            .setWaitForNoInitializingShards(true)
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        // Creating another index with 30 primary and 1 replica
+        createIndex(
+            "test-2",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numOfReplica)
+                .build()
+        );
+
+        health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setIndices("test-1", "test-2")
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes(Integer.toString(nodeCountPerAZ * 3 - nodesToStop))
+            .setWaitForNoRelocatingShards(true)
+            .setWaitForNoInitializingShards(true)
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        // Restarting the nodes back
+        for (int i = 0; i < nodesToStop; i++) {
+            internalCluster().startNode(
+                Settings.builder()
+                    .put("node.name", nodes_in_zone_a.get(i))
+                    .put(nodeDataPathSettings.get(i))
+                    .put(commonSettings)
+                    .put("node.attr.zone", "a")
+                    .build()
+            );
+        }
+        client().admin().cluster().prepareReroute().setRetryFailed(true).get();
+
+        health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setIndices("test-1", "test-2")
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes(Integer.toString(nodeCountPerAZ * 3))
+            .setWaitForGreenStatus()
+            .setWaitForActiveShards(2 * numOfShards * (numOfReplica + 1))
+            .setWaitForNoRelocatingShards(true)
+            .setWaitForNoInitializingShards(true)
+            .execute()
+            .actionGet();
+        clusterState = client().admin().cluster().prepareState().execute().actionGet().getState();
+
+        // All shards should be started now and cluster health should be green
+        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(2 * numOfShards * (numOfReplica + 1)));
+        assertThat(health.isTimedOut(), equalTo(false));
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/ClusterRerouteIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/ClusterRerouteIT.java
index ee2a8784fa0ed..dbcb030d8a4f7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/ClusterRerouteIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/ClusterRerouteIT.java
@@ -58,18 +58,18 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider.Allocation;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.Priority;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
-import org.opensearch.test.MockLogAppender;
 
 import java.nio.file.Path;
 import java.util.Arrays;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/FilteringAllocationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/FilteringAllocationIT.java
index 398adbd0d1ca5..ff95cca5ffde9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/FilteringAllocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/allocation/FilteringAllocationIT.java
@@ -42,9 +42,9 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.decider.FilterAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/AwarenessAttributeDecommissionIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/AwarenessAttributeDecommissionIT.java
new file mode 100644
index 0000000000000..b33d57ed43189
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/AwarenessAttributeDecommissionIT.java
@@ -0,0 +1,1157 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.core.LogEvent;
+import org.opensearch.OpenSearchTimeoutException;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionResponse;
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateObserver;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.cluster.decommission.DecommissioningFailedException;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.discovery.Discovery;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.RemoteTransportException;
+import org.opensearch.transport.Transport;
+import org.opensearch.transport.TransportService;
+import org.junit.After;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Predicate;
+
+import static org.opensearch.test.NodeRoles.onlyRole;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoTimeout;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class AwarenessAttributeDecommissionIT extends OpenSearchIntegTestCase {
+    private final Logger logger = LogManager.getLogger(AwarenessAttributeDecommissionIT.class);
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Collections.singletonList(MockTransportService.TestPlugin.class);
+    }
+
+    @After
+    public void cleanup() throws Exception {
+        assertNoTimeout(client().admin().cluster().prepareHealth().get());
+    }
+
+    public void testDecommissionFailedWhenNotZoneAware() throws Exception {
+        Settings commonSettings = Settings.builder().build();
+        // Start 3 cluster manager eligible nodes
+        internalCluster().startClusterManagerOnlyNodes(3, Settings.builder().put(commonSettings).build());
+        // start 3 data nodes
+        internalCluster().startDataOnlyNodes(3, Settings.builder().put(commonSettings).build());
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-1");
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        assertBusy(() -> {
+            DecommissioningFailedException ex = expectThrows(
+                DecommissioningFailedException.class,
+                () -> client().execute(DecommissionAction.INSTANCE, decommissionRequest).actionGet()
+            );
+            assertTrue(ex.getMessage().contains("invalid awareness attribute requested for decommissioning"));
+        });
+    }
+
+    public void testDecommissionFailedWhenNotForceZoneAware() throws Exception {
+        Settings commonSettings = Settings.builder().put("cluster.routing.allocation.awareness.attributes", "zone").build();
+        // Start 3 cluster manager eligible nodes
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+        logger.info("--> starting data node each on zones 'a' & 'b' & 'c'");
+        internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "a").build());
+        internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "b").build());
+        internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "c").build());
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "a");
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        assertBusy(() -> {
+            DecommissioningFailedException ex = expectThrows(
+                DecommissioningFailedException.class,
+                () -> client().execute(DecommissionAction.INSTANCE, decommissionRequest).actionGet()
+            );
+            assertTrue(ex.getMessage().contains("doesn't have the decommissioning attribute"));
+        });
+    }
+
+    public void testNodesRemovedAfterZoneDecommission_ClusterManagerNotInToBeDecommissionedZone() throws Exception {
+        assertNodesRemovedAfterZoneDecommission(false);
+    }
+
+    public void testNodesRemovedAfterZoneDecommission_ClusterManagerInToBeDecommissionedZone() throws Exception {
+        assertNodesRemovedAfterZoneDecommission(true);
+    }
+
+    public void testInvariantsAndLogsOnDecommissionedNodes() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 0.0, "b", 1.0, "c", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        logger.info("--> starting decommissioning nodes in zone {}", 'a');
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "a");
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+        DecommissionResponse decommissionResponse = client().execute(DecommissionAction.INSTANCE, decommissionRequest).get();
+        assertTrue(decommissionResponse.isAcknowledged());
+
+        // Will wait for all events to complete
+        client().admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        String decommissionedNode = randomFrom(clusterManagerNodes.get(0), dataNodes.get(0));
+        String activeNode = dataNodes.get(1);
+
+        ClusterService decommissionedNodeClusterService = internalCluster().getInstance(ClusterService.class, decommissionedNode);
+        DecommissionAttributeMetadata metadata = decommissionedNodeClusterService.state()
+            .metadata()
+            .custom(DecommissionAttributeMetadata.TYPE);
+        // The decommissioned node would not be having status as SUCCESS as it was kicked out later
+        // and not receiving any further state updates
+        // This also helps to test metadata status updates was received by this node until it got kicked by the leader
+        assertEquals(metadata.decommissionAttribute(), decommissionAttribute);
+        assertNotNull(metadata.status());
+        assertEquals(metadata.status(), DecommissionStatus.IN_PROGRESS);
+
+        // assert the node has decommissioned attribute
+        assertEquals(decommissionedNodeClusterService.localNode().getAttributes().get("zone"), "a");
+
+        // assert exception on decommissioned node
+        Logger clusterLogger = LogManager.getLogger(JoinHelper.class);
+        MockLogAppender mockLogAppender = MockLogAppender.createForLoggers(clusterLogger);
+        mockLogAppender.addExpectation(
+            new MockLogAppender.PatternSeenEventExpectation(
+                "test",
+                JoinHelper.class.getCanonicalName(),
+                Level.INFO,
+                "local node is decommissioned \\[.*]\\. Will not be able to join the cluster"
+            )
+        );
+        mockLogAppender.addExpectation(
+            new MockLogAppender.SeenEventExpectation("test", JoinHelper.class.getCanonicalName(), Level.INFO, "failed to join") {
+                @Override
+                public boolean innerMatch(LogEvent event) {
+                    return event.getThrown() != null
+                        && event.getThrown().getClass() == RemoteTransportException.class
+                        && event.getThrown().getCause() != null
+                        && event.getThrown().getCause().getClass() == NodeDecommissionedException.class;
+                }
+            }
+        );
+        TransportService clusterManagerTransportService = internalCluster().getInstance(
+            TransportService.class,
+            internalCluster().getClusterManagerName(activeNode)
+        );
+        MockTransportService decommissionedNodeTransportService = (MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            decommissionedNode
+        );
+        final CountDownLatch countDownLatch = new CountDownLatch(2);
+        decommissionedNodeTransportService.addSendBehavior(
+            clusterManagerTransportService,
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(JoinHelper.JOIN_ACTION_NAME)) {
+                    countDownLatch.countDown();
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+        decommissionedNodeTransportService.addConnectBehavior(clusterManagerTransportService, Transport::openConnection);
+        countDownLatch.await();
+        mockLogAppender.assertAllExpectationsMatched();
+
+        // decommissioned node should have Coordinator#localNodeCommissioned = false
+        Coordinator coordinator = (Coordinator) internalCluster().getInstance(Discovery.class, decommissionedNode);
+        assertFalse(coordinator.localNodeCommissioned());
+
+        // Check cluster health API for decommissioned and active node
+        ClusterHealthResponse activeNodeLocalHealth = client(activeNode).admin()
+            .cluster()
+            .prepareHealth()
+            .setLocal(true)
+            .setEnsureNodeWeighedIn(true)
+            .execute()
+            .actionGet();
+        assertFalse(activeNodeLocalHealth.isTimedOut());
+
+        ClusterHealthResponse decommissionedNodeLocalHealth = client(decommissionedNode).admin()
+            .cluster()
+            .prepareHealth()
+            .setLocal(true)
+            .execute()
+            .actionGet();
+        assertFalse(decommissionedNodeLocalHealth.isTimedOut());
+
+        NodeDecommissionedException ex = expectThrows(
+            NodeDecommissionedException.class,
+            () -> client(decommissionedNode).admin()
+                .cluster()
+                .prepareHealth()
+                .setLocal(true)
+                .setEnsureNodeWeighedIn(true)
+                .execute()
+                .actionGet()
+        );
+        assertTrue(ex.getMessage().contains("local node is decommissioned"));
+
+        // Recommissioning the zone back to gracefully succeed the test once above tests succeeds
+        DeleteDecommissionStateResponse deleteDecommissionStateResponse = client(activeNode).execute(
+            DeleteDecommissionStateAction.INSTANCE,
+            new DeleteDecommissionStateRequest()
+        ).get();
+        assertTrue(deleteDecommissionStateResponse.isAcknowledged());
+
+        ClusterService activeNodeClusterService = internalCluster().getInstance(ClusterService.class, activeNode);
+        ClusterStateObserver clusterStateObserver = new ClusterStateObserver(
+            activeNodeClusterService,
+            null,
+            logger,
+            client(activeNode).threadPool().getThreadContext()
+        );
+        CountDownLatch expectedStateLatch = new CountDownLatch(1);
+        Predicate<ClusterState> expectedClusterStatePredicate = clusterState -> {
+            if (clusterState.metadata().decommissionAttributeMetadata() != null) return false;
+            if (clusterState.metadata().coordinationMetadata().getVotingConfigExclusions().isEmpty() == false) return false;
+            if (clusterState.nodes().getNodes().size() != 6) return false;
+            return clusterState.metadata().coordinationMetadata().getLastCommittedConfiguration().getNodeIds().size() == 3;
+        };
+
+        ClusterState currentState = activeNodeClusterService.state();
+        if (expectedClusterStatePredicate.test(currentState)) {
+            logger.info("cluster restored");
+            expectedStateLatch.countDown();
+        } else {
+            clusterStateObserver.waitForNextChange(new ClusterStateObserver.Listener() {
+                @Override
+                public void onNewClusterState(ClusterState state) {
+                    logger.info("cluster restored");
+                    expectedStateLatch.countDown();
+                }
+
+                @Override
+                public void onClusterServiceClose() {
+                    throw new AssertionError("unexpected close");
+                }
+
+                @Override
+                public void onTimeout(TimeValue timeout) {
+                    throw new AssertionError("unexpected timeout");
+                }
+            }, expectedClusterStatePredicate);
+        }
+        // if the below condition is passed, then we are sure that config size is restored
+        assertTrue(expectedStateLatch.await(180, TimeUnit.SECONDS));
+        // will wait for cluster to stabilise with a timeout of 2 min as by then all nodes should have joined the cluster
+        ensureStableCluster(6);
+    }
+
+    private void assertNodesRemovedAfterZoneDecommission(boolean originalClusterManagerDecommission) throws Exception {
+        int dataNodeCountPerAZ = 4;
+        List<String> zones = new ArrayList<>(Arrays.asList("a", "b", "c"));
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+        Map<String, String> clusterManagerNameToZone = new HashMap<>();
+        clusterManagerNameToZone.put(clusterManagerNodes.get(0), "a");
+        clusterManagerNameToZone.put(clusterManagerNodes.get(1), "b");
+        clusterManagerNameToZone.put(clusterManagerNodes.get(2), "c");
+
+        logger.info("--> starting 4 data nodes each on zones 'a' & 'b' & 'c'");
+        Map<String, List<String>> zoneToNodesMap = new HashMap<>();
+        zoneToNodesMap.put(
+            "a",
+            internalCluster().startDataOnlyNodes(
+                dataNodeCountPerAZ,
+                Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+            )
+        );
+        zoneToNodesMap.put(
+            "b",
+            internalCluster().startDataOnlyNodes(
+                dataNodeCountPerAZ,
+                Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+            )
+        );
+        zoneToNodesMap.put(
+            "c",
+            internalCluster().startDataOnlyNodes(
+                dataNodeCountPerAZ,
+                Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+            )
+        );
+        ensureStableCluster(15);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(15))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        String originalClusterManager = internalCluster().getClusterManagerName();
+        String originalClusterManagerZone = clusterManagerNameToZone.get(originalClusterManager);
+        logger.info("--> original cluster manager - name {}, zone {}", originalClusterManager, originalClusterManagerZone);
+
+        String zoneToDecommission = originalClusterManagerZone;
+
+        if (originalClusterManagerDecommission == false) {
+            // decommission one zone where active cluster manager is not present
+            List<String> tempZones = new ArrayList<>(zones);
+            tempZones.remove(originalClusterManagerZone);
+            zoneToDecommission = randomFrom(tempZones);
+        }
+        String activeNode;
+        switch (zoneToDecommission) {
+            case "a":
+                activeNode = randomFrom(randomFrom(zoneToNodesMap.get("b")), randomFrom(zoneToNodesMap.get("c")));
+                break;
+            case "b":
+                activeNode = randomFrom(randomFrom(zoneToNodesMap.get("a")), randomFrom(zoneToNodesMap.get("c")));
+                break;
+            case "c":
+                activeNode = randomFrom(randomFrom(zoneToNodesMap.get("a")), randomFrom(zoneToNodesMap.get("b")));
+                break;
+            default:
+                throw new IllegalStateException("unexpected zone decommissioned");
+        }
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = new HashMap<>(Map.of("a", 1.0, "b", 1.0, "c", 1.0));
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        weights.put(zoneToDecommission, 0.0);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        logger.info("--> starting decommissioning nodes in zone {}", zoneToDecommission);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", zoneToDecommission);
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+        DecommissionResponse decommissionResponse = client().execute(DecommissionAction.INSTANCE, decommissionRequest).get();
+        assertTrue(decommissionResponse.isAcknowledged());
+
+        client(activeNode).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        ClusterState clusterState = client(activeNode).admin().cluster().prepareState().execute().actionGet().getState();
+
+        // assert that number of nodes should be 10 ( 2 cluster manager nodes + 8 data nodes )
+        assertEquals(clusterState.nodes().getNodes().size(), 10);
+        assertEquals(clusterState.nodes().getDataNodes().size(), 8);
+        assertEquals(clusterState.nodes().getClusterManagerNodes().size(), 2);
+
+        Iterator<DiscoveryNode> discoveryNodeIterator = clusterState.nodes().getNodes().values().iterator();
+        while (discoveryNodeIterator.hasNext()) {
+            // assert no node has decommissioned attribute
+            DiscoveryNode node = discoveryNodeIterator.next();
+            assertNotEquals(node.getAttributes().get("zone"), zoneToDecommission);
+
+            // assert no node is decommissioned from Coordinator#localNodeCommissioned
+            Coordinator coordinator = (Coordinator) internalCluster().getInstance(Discovery.class, node.getName());
+            assertTrue(coordinator.localNodeCommissioned());
+        }
+
+        // assert that decommission status is successful
+        GetDecommissionStateResponse response = client(activeNode).execute(
+            GetDecommissionStateAction.INSTANCE,
+            new GetDecommissionStateRequest(decommissionAttribute.attributeName())
+        ).get();
+        assertEquals(response.getAttributeValue(), decommissionAttribute.attributeValue());
+        assertEquals(response.getDecommissionStatus(), DecommissionStatus.SUCCESSFUL);
+
+        // assert that no node present in Voting Config Exclusion
+        assertEquals(clusterState.metadata().coordinationMetadata().getVotingConfigExclusions().size(), 0);
+
+        String currentClusterManager = internalCluster().getClusterManagerName(activeNode);
+        assertNotNull(currentClusterManager);
+        if (originalClusterManagerDecommission) {
+            // assert that cluster manager switched during the test
+            assertNotEquals(originalClusterManager, currentClusterManager);
+        } else {
+            // assert that cluster manager didn't switch during test
+            assertEquals(originalClusterManager, currentClusterManager);
+        }
+
+        // Will wait for all events to complete
+        client(activeNode).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        // Recommissioning the zone back to gracefully succeed the test once above tests succeeds
+        DeleteDecommissionStateResponse deleteDecommissionStateResponse = client(currentClusterManager).execute(
+            DeleteDecommissionStateAction.INSTANCE,
+            new DeleteDecommissionStateRequest()
+        ).get();
+        assertTrue(deleteDecommissionStateResponse.isAcknowledged());
+
+        // will wait for cluster to stabilise with a timeout of 2 min as by then all nodes should have joined the cluster
+        ensureStableCluster(15, TimeValue.timeValueMinutes(2));
+    }
+
+    public void testDecommissionFailedWhenDifferentAttributeAlreadyDecommissioned() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+        logger.info("--> starting 1 nodes each on zones 'a' & 'b' & 'c'");
+        internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "a").build());
+        internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "b").build());
+        String node_in_c = internalCluster().startDataOnlyNode(Settings.builder().put(commonSettings).put("node.attr.zone", "c").build());
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 0.0, "b", 1.0, "c", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        logger.info("--> starting decommissioning nodes in zone {}", 'a');
+        DecommissionRequest decommissionRequest = new DecommissionRequest(new DecommissionAttribute("zone", "a"));
+        DecommissionResponse decommissionResponse = client().execute(DecommissionAction.INSTANCE, decommissionRequest).get();
+        assertTrue(decommissionResponse.isAcknowledged());
+
+        DecommissionRequest newDecommissionRequest = new DecommissionRequest(new DecommissionAttribute("zone", "b"));
+        assertBusy(
+            () -> expectThrows(
+                DecommissioningFailedException.class,
+                () -> client(node_in_c).execute(DecommissionAction.INSTANCE, newDecommissionRequest).actionGet()
+            )
+        );
+
+        // Will wait for all events to complete
+        client(node_in_c).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        // Recommissioning the zone back to gracefully succeed the test once above tests succeeds
+        DeleteDecommissionStateResponse deleteDecommissionStateResponse = client(node_in_c).execute(
+            DeleteDecommissionStateAction.INSTANCE,
+            new DeleteDecommissionStateRequest()
+        ).get();
+        assertTrue(deleteDecommissionStateResponse.isAcknowledged());
+
+        // will wait for cluster to stabilise with a timeout of 2 min as by then all nodes should have joined the cluster
+        ensureStableCluster(6, TimeValue.timeValueMinutes(2));
+    }
+
+    public void testDecommissionStatusUpdatePublishedToAllNodes() throws ExecutionException, InterruptedException {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        ensureStableCluster(6);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        logger.info("--> starting decommissioning nodes in zone {}", 'c');
+        String activeNode = randomFrom(dataNodes.get(0), dataNodes.get(1));
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "c");
+        // Set the timeout to 0 to do immediate Decommission
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+        DecommissionResponse decommissionResponse = client(activeNode).execute(DecommissionAction.INSTANCE, decommissionRequest).get();
+        assertTrue(decommissionResponse.isAcknowledged());
+
+        // Will wait for all events to complete
+        client(activeNode).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        logger.info("--> Received LANGUID event");
+
+        // assert that decommission status is successful
+        GetDecommissionStateResponse response = client(activeNode).execute(
+            GetDecommissionStateAction.INSTANCE,
+            new GetDecommissionStateRequest(decommissionAttribute.attributeName())
+        ).get();
+        assertEquals(response.getAttributeValue(), decommissionAttribute.attributeValue());
+        assertEquals(DecommissionStatus.SUCCESSFUL, response.getDecommissionStatus());
+
+        logger.info("--> Decommission status is successful");
+        ClusterState clusterState = client(activeNode).admin().cluster().prepareState().execute().actionGet().getState();
+        assertEquals(4, clusterState.nodes().getSize());
+
+        logger.info("--> Got cluster state with 4 nodes.");
+        // assert status on nodes that are part of cluster currently
+        Iterator<DiscoveryNode> discoveryNodeIterator = clusterState.nodes().getNodes().values().iterator();
+        DiscoveryNode clusterManagerNodeAfterDecommission = null;
+        while (discoveryNodeIterator.hasNext()) {
+            // assert no node has decommissioned attribute
+            DiscoveryNode node = discoveryNodeIterator.next();
+            assertNotEquals(node.getAttributes().get("zone"), "c");
+            if (node.isClusterManagerNode()) {
+                clusterManagerNodeAfterDecommission = node;
+            }
+            // assert all the nodes has status as SUCCESSFUL
+            ClusterService localNodeClusterService = internalCluster().getInstance(ClusterService.class, node.getName());
+            assertEquals(
+                localNodeClusterService.state().metadata().decommissionAttributeMetadata().status(),
+                DecommissionStatus.SUCCESSFUL
+            );
+        }
+        assertNotNull("Cluster Manager not found after decommission", clusterManagerNodeAfterDecommission);
+        logger.info("--> Cluster Manager node found after decommission");
+
+        // assert status on decommissioned node
+        // Here we will verify that until it got kicked out, it received appropriate status updates
+        // decommissioned nodes hence will have status as IN_PROGRESS as it will be kicked out later after this
+        // and won't receive status update to SUCCESSFUL
+        String randomDecommissionedNode = randomFrom(clusterManagerNodes.get(2), dataNodes.get(2));
+        ClusterService decommissionedNodeClusterService = internalCluster().getInstance(ClusterService.class, randomDecommissionedNode);
+        assertEquals(
+            decommissionedNodeClusterService.state().metadata().decommissionAttributeMetadata().status(),
+            DecommissionStatus.IN_PROGRESS
+        );
+        logger.info("--> Verified the decommissioned node has in_progress state.");
+
+        // Will wait for all events to complete
+        client(activeNode).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+        logger.info("--> Got LANGUID event");
+        // Recommissioning the zone back to gracefully succeed the test once above tests succeeds
+        DeleteDecommissionStateResponse deleteDecommissionStateResponse = client(activeNode).execute(
+            DeleteDecommissionStateAction.INSTANCE,
+            new DeleteDecommissionStateRequest()
+        ).get();
+        assertTrue(deleteDecommissionStateResponse.isAcknowledged());
+        logger.info("--> Deleting decommission done.");
+
+        // will wait for cluster to stabilise with a timeout of 2 min (findPeerInterval for decommissioned nodes)
+        // as by then all nodes should have joined the cluster
+        ensureStableCluster(6, TimeValue.timeValueSeconds(121));
+    }
+
+    public void testDecommissionFailedWhenAttributeNotWeighedAway() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+        // Start 3 cluster manager eligible nodes
+        internalCluster().startClusterManagerOnlyNodes(3, Settings.builder().put(commonSettings).build());
+        // start 3 data nodes
+        internalCluster().startDataOnlyNodes(3, Settings.builder().put(commonSettings).build());
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "c");
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+        assertBusy(() -> {
+            DecommissioningFailedException ex = expectThrows(
+                DecommissioningFailedException.class,
+                () -> client().execute(DecommissionAction.INSTANCE, decommissionRequest).actionGet()
+            );
+            assertTrue(
+                ex.getMessage()
+                    .contains("no weights are set to the attribute. Please set appropriate weights before triggering decommission action")
+            );
+        });
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        assertBusy(() -> {
+            DecommissioningFailedException ex = expectThrows(
+                DecommissioningFailedException.class,
+                () -> client().execute(DecommissionAction.INSTANCE, decommissionRequest).actionGet()
+            );
+            assertTrue(ex.getMessage().contains("weight for decommissioned attribute is expected to be [0.0] but found [1.0]"));
+        });
+    }
+
+    public void testDecommissionFailedWithOnlyOneAttributeValueForLeader() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "b") // force zone values is only set for zones of routing nodes
+            .build();
+        // Start 3 cluster manager eligible nodes in zone a
+        internalCluster().startClusterManagerOnlyNodes(3, Settings.builder().put(commonSettings).put("node.attr.zone", "a").build());
+        // Start 3 data nodes in zone b
+        internalCluster().startDataOnlyNodes(3, Settings.builder().put(commonSettings).put("node.attr.zone", "b").build());
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        logger.info("--> setting shard routing weights");
+        Map<String, Double> weights = Map.of("b", 1.0); // weights are expected to be set only for routing nodes
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        // prepare request to attempt to decommission zone 'a'
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "a");
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+
+        // since there is just one zone present in the cluster, and on initiating decommission for that zone,
+        // although all the nodes would be added to voting config exclusion list, but those nodes won't be able to
+        // abdicate themselves as we wouldn't have any other leader eligible node which would be declare itself cluster manager
+        // and hence due to which the leader won't get abdicated and decommission request should eventually fail.
+        // And in this case, to ensure decommission request doesn't leave mutating change in the cluster, we ensure
+        // that no exclusion is set to the cluster and state for decommission is marked as FAILED
+        OpenSearchTimeoutException ex = expectThrows(
+            OpenSearchTimeoutException.class,
+            () -> client().execute(DecommissionAction.INSTANCE, decommissionRequest).actionGet()
+        );
+        assertTrue(ex.getMessage().contains("while removing to-be-decommissioned cluster manager eligible nodes"));
+
+        ClusterService leaderClusterService = internalCluster().getInstance(
+            ClusterService.class,
+            internalCluster().getClusterManagerName()
+        );
+        ClusterStateObserver clusterStateObserver = new ClusterStateObserver(
+            leaderClusterService,
+            null,
+            logger,
+            client(internalCluster().getClusterManagerName()).threadPool().getThreadContext()
+        );
+        CountDownLatch expectedStateLatch = new CountDownLatch(1);
+
+        ClusterState currentState = internalCluster().clusterService().state();
+        if (currentState.getVotingConfigExclusions().isEmpty()) {
+            logger.info("exclusion already cleared");
+            expectedStateLatch.countDown();
+        } else {
+            clusterStateObserver.waitForNextChange(new WaitForClearVotingConfigExclusion(expectedStateLatch));
+        }
+        // if the below condition is passed, then we are sure exclusion is cleared
+        assertTrue(expectedStateLatch.await(30, TimeUnit.SECONDS));
+
+        expectedStateLatch = new CountDownLatch(1);
+        currentState = internalCluster().clusterService().state();
+        DecommissionAttributeMetadata decommissionAttributeMetadata = currentState.metadata().decommissionAttributeMetadata();
+        if (decommissionAttributeMetadata != null && decommissionAttributeMetadata.status().equals(DecommissionStatus.FAILED)) {
+            logger.info("decommission status has already turned false");
+            expectedStateLatch.countDown();
+        } else {
+            clusterStateObserver.waitForNextChange(new WaitForFailedDecommissionState(expectedStateLatch));
+        }
+
+        // if the below condition is passed, then we are sure current decommission status is marked FAILED
+        assertTrue(expectedStateLatch.await(30, TimeUnit.SECONDS));
+
+        // ensure all nodes are part of cluster
+        ensureStableCluster(6, TimeValue.timeValueMinutes(2));
+    }
+
+    public void testDecommissionAcknowledgedIfWeightsNotSetForNonRoutingNode() throws ExecutionException, InterruptedException {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'd' & 'e' & 'f'");
+        List<String> clusterManagerNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "d")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "e")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "f")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        List<String> dataNodes = internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        ensureStableCluster(6);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        logger.info("--> starting decommissioning nodes in zone {}", 'd');
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "d");
+        // Set the timeout to 0 to do immediate Decommission
+        DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+        decommissionRequest.setNoDelay(true);
+        DecommissionResponse decommissionResponse = client(dataNodes.get(0)).execute(DecommissionAction.INSTANCE, decommissionRequest)
+            .get();
+        assertTrue(decommissionResponse.isAcknowledged());
+
+        client(dataNodes.get(0)).admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
+
+        ClusterState clusterState = client(dataNodes.get(0)).admin().cluster().prepareState().execute().actionGet().getState();
+
+        // assert that number of nodes should be 5 ( 2 cluster manager nodes + 3 data nodes )
+        assertEquals(clusterState.nodes().getNodes().size(), 5);
+        assertEquals(clusterState.nodes().getDataNodes().size(), 3);
+        assertEquals(clusterState.nodes().getClusterManagerNodes().size(), 2);
+
+        // Recommissioning the zone back to gracefully succeed the test once above tests succeeds
+        DeleteDecommissionStateResponse deleteDecommissionStateResponse = client(dataNodes.get(0)).execute(
+            DeleteDecommissionStateAction.INSTANCE,
+            new DeleteDecommissionStateRequest()
+        ).get();
+        assertTrue(deleteDecommissionStateResponse.isAcknowledged());
+
+        // will wait for cluster to stabilise with a timeout of 2 min as by then all nodes should have joined the cluster
+        ensureStableCluster(6, TimeValue.timeValueMinutes(2));
+    }
+
+    public void testConcurrentDecommissionAction() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> start 3 cluster manager nodes on zones 'a' & 'b' & 'c'");
+        internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+                .build()
+        );
+        logger.info("--> start 3 data nodes on zones 'a' & 'b' & 'c'");
+        internalCluster().startNodes(
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "a")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "b")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build(),
+            Settings.builder()
+                .put(commonSettings)
+                .put("node.attr.zone", "c")
+                .put(onlyRole(commonSettings, DiscoveryNodeRole.DATA_ROLE))
+                .build()
+        );
+
+        ensureStableCluster(6);
+        ClusterHealthResponse health = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForGreenStatus()
+            .setWaitForNodes(Integer.toString(6))
+            .execute()
+            .actionGet();
+        assertFalse(health.isTimedOut());
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 0.0, "b", 1.0, "c", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(weightedRoutingResponse.isAcknowledged());
+
+        AtomicInteger numRequestAcknowledged = new AtomicInteger();
+        AtomicInteger numRequestUnAcknowledged = new AtomicInteger();
+        AtomicInteger numRequestFailed = new AtomicInteger();
+        int concurrentRuns = randomIntBetween(5, 10);
+        TestThreadPool testThreadPool = null;
+        logger.info("--> starting {} concurrent decommission action in zone {}", concurrentRuns, 'a');
+        try {
+            testThreadPool = new TestThreadPool(AwarenessAttributeDecommissionIT.class.getName());
+            List<Runnable> operationThreads = new ArrayList<>();
+            CountDownLatch countDownLatch = new CountDownLatch(concurrentRuns);
+            for (int i = 0; i < concurrentRuns; i++) {
+                Runnable thread = () -> {
+                    logger.info("Triggering decommission action");
+                    DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "a");
+                    DecommissionRequest decommissionRequest = new DecommissionRequest(decommissionAttribute);
+                    decommissionRequest.setNoDelay(true);
+                    try {
+                        DecommissionResponse decommissionResponse = client().execute(DecommissionAction.INSTANCE, decommissionRequest)
+                            .get();
+                        if (decommissionResponse.isAcknowledged()) {
+                            numRequestAcknowledged.incrementAndGet();
+                        } else {
+                            numRequestUnAcknowledged.incrementAndGet();
+                        }
+                    } catch (Exception e) {
+                        numRequestFailed.incrementAndGet();
+                    }
+                    countDownLatch.countDown();
+                };
+                operationThreads.add(thread);
+            }
+            TestThreadPool finalTestThreadPool = testThreadPool;
+            operationThreads.forEach(runnable -> finalTestThreadPool.executor("generic").execute(runnable));
+            countDownLatch.await();
+        } finally {
+            ThreadPool.terminate(testThreadPool, 500, TimeUnit.MILLISECONDS);
+        }
+        assertEquals(concurrentRuns, numRequestAcknowledged.get() + numRequestUnAcknowledged.get() + numRequestFailed.get());
+        assertEquals(concurrentRuns - 1, numRequestFailed.get());
+        assertEquals(1, numRequestAcknowledged.get() + numRequestUnAcknowledged.get());
+    }
+
+    private static class WaitForFailedDecommissionState implements ClusterStateObserver.Listener {
+
+        final CountDownLatch doneLatch;
+
+        WaitForFailedDecommissionState(CountDownLatch latch) {
+            this.doneLatch = latch;
+        }
+
+        @Override
+        public void onNewClusterState(ClusterState state) {
+            DecommissionAttributeMetadata decommissionAttributeMetadata = state.metadata().decommissionAttributeMetadata();
+            if (decommissionAttributeMetadata != null && decommissionAttributeMetadata.status().equals(DecommissionStatus.FAILED)) {
+                doneLatch.countDown();
+            }
+        }
+
+        @Override
+        public void onClusterServiceClose() {
+            throw new AssertionError("unexpected close");
+        }
+
+        @Override
+        public void onTimeout(TimeValue timeout) {
+            throw new AssertionError("unexpected timeout");
+        }
+    }
+
+    private static class WaitForClearVotingConfigExclusion implements ClusterStateObserver.Listener {
+
+        final CountDownLatch doneLatch;
+
+        WaitForClearVotingConfigExclusion(CountDownLatch latch) {
+            this.doneLatch = latch;
+        }
+
+        @Override
+        public void onNewClusterState(ClusterState state) {
+            if (state.getVotingConfigExclusions().isEmpty()) {
+                doneLatch.countDown();
+            }
+        }
+
+        @Override
+        public void onClusterServiceClose() {
+            throw new AssertionError("unexpected close");
+        }
+
+        @Override
+        public void onTimeout(TimeValue timeout) {
+            throw new AssertionError("unexpected timeout");
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RareClusterStateIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RareClusterStateIT.java
index 6f4c6fca77196..b3cb15d028090 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RareClusterStateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RareClusterStateIT.java
@@ -34,11 +34,8 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.cluster.ClusterState;
@@ -53,10 +50,12 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.index.Index;
 import org.opensearch.discovery.Discovery;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperService;
@@ -72,10 +71,8 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static org.opensearch.action.DocWriteResponse.Result.CREATED;
-
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
 import static org.hamcrest.Matchers.hasSize;
@@ -105,9 +102,9 @@ public void testAssignmentWithJustAddedNodes() {
         // close to have some unassigned started shards shards..
         client().admin().indices().prepareClose(index).get();
 
-        final String masterName = internalCluster().getMasterName();
-        final ClusterService clusterService = internalCluster().clusterService(masterName);
-        final AllocationService allocationService = internalCluster().getInstance(AllocationService.class, masterName);
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        final ClusterService clusterService = internalCluster().clusterService(clusterManagerName);
+        final AllocationService allocationService = internalCluster().getInstance(AllocationService.class, clusterManagerName);
         clusterService.submitStateUpdateTask("test-inject-node-and-reroute", new ClusterStateUpdateTask() {
             @Override
             public ClusterState execute(ClusterState currentState) {
@@ -159,27 +156,27 @@ private <Req extends ActionRequest, Res extends ActionResponse> ActionFuture<Res
     ) throws Exception {
         // Wait for no publication in progress to not accidentally cancel a publication different from the one triggered by the given
         // request.
-        final Coordinator masterCoordinator = (Coordinator) internalCluster().getCurrentMasterNodeInstance(Discovery.class);
+        final Coordinator clusterManagerCoordinator = (Coordinator) internalCluster().getCurrentClusterManagerNodeInstance(Discovery.class);
         assertBusy(() -> {
-            assertFalse(masterCoordinator.publicationInProgress());
-            final long applierVersion = masterCoordinator.getApplierState().version();
+            assertFalse(clusterManagerCoordinator.publicationInProgress());
+            final long applierVersion = clusterManagerCoordinator.getApplierState().version();
             for (Discovery instance : internalCluster().getInstances(Discovery.class)) {
                 assertEquals(((Coordinator) instance).getApplierState().version(), applierVersion);
             }
         });
         ActionFuture<Res> future = req.execute();
-        assertBusy(() -> assertTrue(masterCoordinator.cancelCommittedPublication()));
+        assertBusy(() -> assertTrue(clusterManagerCoordinator.cancelCommittedPublication()));
         return future;
     }
 
     public void testDeleteCreateInOneBulk() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
         assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("2").get().isTimedOut());
         prepareCreate("test").setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)).get();
         ensureGreen("test");
 
-        // block none master node.
+        // block none cluster-manager node.
         BlockClusterStateProcessing disruption = new BlockClusterStateProcessing(dataNode, random());
         internalCluster().setDisruptionScheme(disruption);
         logger.info("--> indexing a doc");
@@ -202,9 +199,11 @@ public void testDeleteCreateInOneBulk() throws Exception {
         ensureGreen(TimeValue.timeValueMinutes(30), "test");
         // due to publish_timeout of 0, wait for data node to have cluster state fully applied
         assertBusy(() -> {
-            long masterClusterStateVersion = internalCluster().clusterService(internalCluster().getMasterName()).state().version();
+            long clusterManagerClusterStateVersion = internalCluster().clusterService(internalCluster().getClusterManagerName())
+                .state()
+                .version();
             long dataClusterStateVersion = internalCluster().clusterService(dataNode).state().version();
-            assertThat(masterClusterStateVersion, equalTo(dataClusterStateVersion));
+            assertThat(clusterManagerClusterStateVersion, equalTo(dataClusterStateVersion));
         });
         assertHitCount(client().prepareSearch("test").get(), 0);
     }
@@ -212,7 +211,7 @@ public void testDeleteCreateInOneBulk() throws Exception {
     public void testDelayedMappingPropagationOnPrimary() throws Exception {
         // Here we want to test that things go well if there is a first request
         // that adds mappings but before mappings are propagated to all nodes
-        // another index request introduces the same mapping. The master node
+        // another index request introduces the same mapping. The cluster-manager node
         // will reply immediately since it did not change the cluster state
         // but the change might not be on the node that performed the indexing
         // operation yet
@@ -220,37 +219,37 @@ public void testDelayedMappingPropagationOnPrimary() throws Exception {
         final List<String> nodeNames = internalCluster().startNodes(2);
         assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("2").get().isTimedOut());
 
-        final String master = internalCluster().getMasterName();
-        assertThat(nodeNames, hasItem(master));
+        final String clusterManager = internalCluster().getClusterManagerName();
+        assertThat(nodeNames, hasItem(clusterManager));
         String otherNode = null;
         for (String node : nodeNames) {
-            if (node.equals(master) == false) {
+            if (node.equals(clusterManager) == false) {
                 otherNode = node;
                 break;
             }
         }
         assertNotNull(otherNode);
 
-        // Don't allocate the shard on the master node
+        // Don't allocate the shard on the cluster-manager node
         assertAcked(
             prepareCreate("index").setSettings(
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                    .put("index.routing.allocation.exclude._name", master)
+                    .put("index.routing.allocation.exclude._name", clusterManager)
             ).get()
         );
         ensureGreen();
 
         // Check routing tables
         ClusterState state = client().admin().cluster().prepareState().get().getState();
-        assertEquals(master, state.nodes().getMasterNode().getName());
+        assertEquals(clusterManager, state.nodes().getClusterManagerNode().getName());
         List<ShardRouting> shards = state.routingTable().allShards("index");
         assertThat(shards, hasSize(1));
         for (ShardRouting shard : shards) {
             if (shard.primary()) {
-                // primary must not be on the master node
-                assertFalse(state.nodes().getMasterNodeId().equals(shard.currentNodeId()));
+                // primary must not be on the cluster-manager node
+                assertFalse(state.nodes().getClusterManagerNodeId().equals(shard.currentNodeId()));
             } else {
                 fail(); // only primaries
             }
@@ -266,7 +265,7 @@ public void testDelayedMappingPropagationOnPrimary() throws Exception {
             client().admin().indices().preparePutMapping("index").setSource("field", "type=long")
         );
 
-        // ...and wait for mappings to be available on master
+        // ...and wait for mappings to be available on cluster-manager
         assertBusy(() -> {
             MappingMetadata typeMappings = client().admin().indices().prepareGetMappings("index").get().getMappings().get("index");
             assertNotNull(typeMappings);
@@ -308,24 +307,24 @@ public void testDelayedMappingPropagationOnReplica() throws Exception {
         final List<String> nodeNames = internalCluster().startNodes(2);
         assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("2").get().isTimedOut());
 
-        final String master = internalCluster().getMasterName();
-        assertThat(nodeNames, hasItem(master));
+        final String clusterManager = internalCluster().getClusterManagerName();
+        assertThat(nodeNames, hasItem(clusterManager));
         String otherNode = null;
         for (String node : nodeNames) {
-            if (node.equals(master) == false) {
+            if (node.equals(clusterManager) == false) {
                 otherNode = node;
                 break;
             }
         }
         assertNotNull(otherNode);
 
-        // Force allocation of the primary on the master node by first only allocating on the master
+        // Force allocation of the primary on the cluster-manager node by first only allocating on the cluster-manager
         // and then allowing all nodes so that the replica gets allocated on the other node
         prepareCreate("index").setSettings(
             Settings.builder()
                 .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                 .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
-                .put("index.routing.allocation.include._name", master)
+                .put("index.routing.allocation.include._name", clusterManager)
         ).get();
         client().admin()
             .indices()
@@ -336,13 +335,13 @@ public void testDelayedMappingPropagationOnReplica() throws Exception {
 
         // Check routing tables
         ClusterState state = client().admin().cluster().prepareState().get().getState();
-        assertEquals(master, state.nodes().getMasterNode().getName());
+        assertEquals(clusterManager, state.nodes().getClusterManagerNode().getName());
         List<ShardRouting> shards = state.routingTable().allShards("index");
         assertThat(shards, hasSize(2));
         for (ShardRouting shard : shards) {
             if (shard.primary()) {
-                // primary must be on the master
-                assertEquals(state.nodes().getMasterNodeId(), shard.currentNodeId());
+                // primary must be on the cluster-manager
+                assertEquals(state.nodes().getClusterManagerNodeId(), shard.currentNodeId());
             } else {
                 assertTrue(shard.active());
             }
@@ -357,9 +356,9 @@ public void testDelayedMappingPropagationOnReplica() throws Exception {
         );
 
         final Index index = resolveIndex("index");
-        // Wait for mappings to be available on master
+        // Wait for mappings to be available on cluster-manager
         assertBusy(() -> {
-            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, master);
+            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, clusterManager);
             final IndexService indexService = indicesService.indexServiceSafe(index);
             assertNotNull(indexService);
             final MapperService mapperService = indexService.mapperService();
@@ -381,9 +380,9 @@ public void testDelayedMappingPropagationOnReplica() throws Exception {
             client().prepareIndex("index").setId("2").setSource("field2", 42)
         );
 
-        // ...and wait for second mapping to be available on master
+        // ...and wait for second mapping to be available on cluster-manager
         assertBusy(() -> {
-            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, master);
+            final IndicesService indicesService = internalCluster().getInstance(IndicesService.class, clusterManager);
             final IndexService indexService = indicesService.indexServiceSafe(index);
             assertNotNull(indexService);
             final MapperService mapperService = indexService.mapperService();
@@ -392,7 +391,7 @@ public void testDelayedMappingPropagationOnReplica() throws Exception {
             assertNotNull(mapper.mappers().getMapper("field2"));
         });
 
-        assertBusy(() -> assertTrue(client().prepareGet("index", "2").get().isExists()));
+        assertBusy(() -> assertTrue(client().prepareGet("index", "2").setPreference("_primary").get().isExists()));
 
         // The mappings have not been propagated to the replica yet as a consequence the document count not be indexed
         // We wait on purpose to make sure that the document is not indexed because the shard operation is stalled
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveCustomsCommandIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveCustomsCommandIT.java
index 5037f51e2b3f0..05e8cd4e93d0e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveCustomsCommandIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveCustomsCommandIT.java
@@ -46,7 +46,7 @@
 public class RemoveCustomsCommandIT extends OpenSearchIntegTestCase {
 
     public void testRemoveCustomsAbortedByUser() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
         ensureStableCluster(1);
@@ -59,7 +59,7 @@ public void testRemoveCustomsAbortedByUser() throws Exception {
     }
 
     public void testRemoveCustomsSuccessful() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         createIndex("test");
         client().admin().indices().prepareDelete("test").get();
@@ -85,7 +85,7 @@ public void testRemoveCustomsSuccessful() throws Exception {
     }
 
     public void testCustomDoesNotMatch() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         createIndex("test");
         client().admin().indices().prepareDelete("test").get();
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveSettingsCommandIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveSettingsCommandIT.java
index f908225e9ba91..fcefbd9fa1273 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveSettingsCommandIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/RemoveSettingsCommandIT.java
@@ -49,7 +49,7 @@
 public class RemoveSettingsCommandIT extends OpenSearchIntegTestCase {
 
     public void testRemoveSettingsAbortedByUser() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         client().admin()
             .cluster()
@@ -78,7 +78,7 @@ public void testRemoveSettingsAbortedByUser() throws Exception {
     }
 
     public void testRemoveSettingsSuccessful() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         client().admin()
             .cluster()
@@ -122,7 +122,7 @@ public void testRemoveSettingsSuccessful() throws Exception {
     }
 
     public void testSettingDoesNotMatch() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         client().admin()
             .cluster()
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/UnsafeBootstrapAndDetachCommandIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/UnsafeBootstrapAndDetachCommandIT.java
index 1447379b93ec8..b30eb1f3e3b39 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/UnsafeBootstrapAndDetachCommandIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/UnsafeBootstrapAndDetachCommandIT.java
@@ -44,6 +44,7 @@
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.gateway.PersistedClusterStateService;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.node.Node.DiscoverySettings;
 import org.opensearch.test.InternalTestCluster;
@@ -55,16 +56,16 @@
 import java.util.Locale;
 import java.util.Objects;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.notNullValue;
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.gateway.DanglingIndicesState.AUTO_IMPORT_DANGLING_INDICES_SETTING;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.indices.recovery.RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.notNullValue;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
 public class UnsafeBootstrapAndDetachCommandIT extends OpenSearchIntegTestCase {
@@ -109,9 +110,15 @@ private MockTerminal executeCommand(
     }
 
     private MockTerminal unsafeBootstrap(Environment environment, boolean abort, Boolean applyClusterReadOnlyBlock) throws Exception {
-        final MockTerminal terminal = executeCommand(new UnsafeBootstrapMasterCommand(), environment, 0, abort, applyClusterReadOnlyBlock);
-        assertThat(terminal.getOutput(), containsString(UnsafeBootstrapMasterCommand.CONFIRMATION_MSG));
-        assertThat(terminal.getOutput(), containsString(UnsafeBootstrapMasterCommand.MASTER_NODE_BOOTSTRAPPED_MSG));
+        final MockTerminal terminal = executeCommand(
+            new UnsafeBootstrapClusterManagerCommand(),
+            environment,
+            0,
+            abort,
+            applyClusterReadOnlyBlock
+        );
+        assertThat(terminal.getOutput(), containsString(UnsafeBootstrapClusterManagerCommand.CONFIRMATION_MSG));
+        assertThat(terminal.getOutput(), containsString(UnsafeBootstrapClusterManagerCommand.CLUSTER_MANAGER_NODE_BOOTSTRAPPED_MSG));
         return terminal;
     }
 
@@ -167,11 +174,21 @@ private void removeBlock() {
         }
     }
 
-    public void testBootstrapNotMasterEligible() {
+    public void testBootstrapNotClusterManagerEligible() {
+        final Environment environment = TestEnvironment.newEnvironment(
+            Settings.builder().put(nonClusterManagerNode(internalCluster().getDefaultSettings())).build()
+        );
+        expectThrows(() -> unsafeBootstrap(environment), UnsafeBootstrapClusterManagerCommand.NOT_CLUSTER_MANAGER_NODE_MSG);
+    }
+
+    public void testBootstrapRemoteClusterEnabled() {
         final Environment environment = TestEnvironment.newEnvironment(
-            Settings.builder().put(nonMasterNode(internalCluster().getDefaultSettings())).build()
+            Settings.builder()
+                .put(internalCluster().getDefaultSettings())
+                .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true)
+                .build()
         );
-        expectThrows(() -> unsafeBootstrap(environment), UnsafeBootstrapMasterCommand.NOT_MASTER_NODE_MSG);
+        expectThrows(() -> unsafeBootstrap(environment), UnsafeBootstrapClusterManagerCommand.REMOTE_CLUSTER_STATE_ENABLED_NODE);
     }
 
     public void testBootstrapNoDataFolder() {
@@ -214,7 +231,7 @@ public void testBootstrapNotBootstrappedCluster() throws Exception {
         );
         assertBusy(() -> {
             ClusterState state = client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-            assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
+            assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
         });
 
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
@@ -224,15 +241,15 @@ public void testBootstrapNotBootstrappedCluster() throws Exception {
         Environment environment = TestEnvironment.newEnvironment(
             Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build()
         );
-        expectThrows(() -> unsafeBootstrap(environment), UnsafeBootstrapMasterCommand.EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG);
+        expectThrows(() -> unsafeBootstrap(environment), UnsafeBootstrapClusterManagerCommand.EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG);
     }
 
     public void testBootstrapNoClusterState() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
         ensureStableCluster(1);
-        NodeEnvironment nodeEnvironment = internalCluster().getMasterNodeInstance(NodeEnvironment.class);
+        NodeEnvironment nodeEnvironment = internalCluster().getClusterManagerNodeInstance(NodeEnvironment.class);
         internalCluster().stopRandomDataNode();
         Environment environment = TestEnvironment.newEnvironment(
             Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build()
@@ -243,11 +260,11 @@ public void testBootstrapNoClusterState() throws IOException {
     }
 
     public void testDetachNoClusterState() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
         ensureStableCluster(1);
-        NodeEnvironment nodeEnvironment = internalCluster().getMasterNodeInstance(NodeEnvironment.class);
+        NodeEnvironment nodeEnvironment = internalCluster().getClusterManagerNodeInstance(NodeEnvironment.class);
         internalCluster().stopRandomDataNode();
         Environment environment = TestEnvironment.newEnvironment(
             Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build()
@@ -258,7 +275,7 @@ public void testDetachNoClusterState() throws IOException {
     }
 
     public void testBootstrapAbortedByUser() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
         ensureStableCluster(1);
@@ -271,7 +288,7 @@ public void testBootstrapAbortedByUser() throws IOException {
     }
 
     public void testDetachAbortedByUser() throws IOException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         String node = internalCluster().startNode();
         Settings dataPathSettings = internalCluster().dataPathSettings(node);
         ensureStableCluster(1);
@@ -283,13 +300,13 @@ public void testDetachAbortedByUser() throws IOException {
         expectThrows(() -> detachCluster(environment, true), OpenSearchNodeCommand.ABORTED_BY_USER_MSG);
     }
 
-    public void test3MasterNodes2Failed() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(2);
-        List<String> masterNodes = new ArrayList<>();
+    public void test3ClusterManagerNodes2Failed() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(2);
+        List<String> clusterManagerNodes = new ArrayList<>();
 
-        logger.info("--> start 1st master-eligible node");
-        masterNodes.add(
-            internalCluster().startMasterOnlyNode(
+        logger.info("--> start 1st cluster-manager-eligible node");
+        clusterManagerNodes.add(
+            internalCluster().startClusterManagerOnlyNode(
                 Settings.builder().put(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey(), "0s").build()
             )
         ); // node ordinal 0
@@ -299,13 +316,13 @@ public void test3MasterNodes2Failed() throws Exception {
             Settings.builder().put(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey(), "0s").build()
         ); // node ordinal 1
 
-        logger.info("--> start 2nd and 3rd master-eligible nodes and bootstrap");
-        masterNodes.addAll(internalCluster().startMasterOnlyNodes(2)); // node ordinals 2 and 3
+        logger.info("--> start 2nd and 3rd cluster-manager-eligible nodes and bootstrap");
+        clusterManagerNodes.addAll(internalCluster().startClusterManagerOnlyNodes(2)); // node ordinals 2 and 3
 
         logger.info("--> wait for all nodes to join the cluster");
         ensureStableCluster(4);
 
-        List<String> currentClusterNodes = new ArrayList<>(masterNodes);
+        List<String> currentClusterNodes = new ArrayList<>(clusterManagerNodes);
         currentClusterNodes.add(dataNode);
         currentClusterNodes.forEach(node -> ensureReadOnlyBlock(false, node));
 
@@ -313,14 +330,14 @@ public void test3MasterNodes2Failed() throws Exception {
         createIndex("test");
         ensureGreen("test");
 
-        Settings master1DataPathSettings = internalCluster().dataPathSettings(masterNodes.get(0));
-        Settings master2DataPathSettings = internalCluster().dataPathSettings(masterNodes.get(1));
-        Settings master3DataPathSettings = internalCluster().dataPathSettings(masterNodes.get(2));
+        Settings clusterManager1DataPathSettings = internalCluster().dataPathSettings(clusterManagerNodes.get(0));
+        Settings clusterManager2DataPathSettings = internalCluster().dataPathSettings(clusterManagerNodes.get(1));
+        Settings clusterManager3DataPathSettings = internalCluster().dataPathSettings(clusterManagerNodes.get(2));
         Settings dataNodeDataPathSettings = internalCluster().dataPathSettings(dataNode);
 
-        logger.info("--> stop 2nd and 3d master eligible node");
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(masterNodes.get(1)));
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(masterNodes.get(2)));
+        logger.info("--> stop 2nd and 3d cluster-manager eligible node");
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(clusterManagerNodes.get(1)));
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(clusterManagerNodes.get(2)));
 
         logger.info("--> ensure NO_MASTER_BLOCK on data-only node");
         assertBusy(() -> {
@@ -332,23 +349,26 @@ public void test3MasterNodes2Failed() throws Exception {
                 .execute()
                 .actionGet()
                 .getState();
-            assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
+            assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
         });
 
-        logger.info("--> try to unsafely bootstrap 1st master-eligible node, while node lock is held");
-        Environment environmentMaster1 = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(master1DataPathSettings).build()
+        logger.info("--> try to unsafely bootstrap 1st cluster-manager-eligible node, while node lock is held");
+        Environment environmentClusterManager1 = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManager1DataPathSettings).build()
+        );
+        expectThrows(
+            () -> unsafeBootstrap(environmentClusterManager1),
+            UnsafeBootstrapClusterManagerCommand.FAILED_TO_OBTAIN_NODE_LOCK_MSG
         );
-        expectThrows(() -> unsafeBootstrap(environmentMaster1), UnsafeBootstrapMasterCommand.FAILED_TO_OBTAIN_NODE_LOCK_MSG);
 
-        logger.info("--> stop 1st master-eligible node and data-only node");
-        NodeEnvironment nodeEnvironment = internalCluster().getMasterNodeInstance(NodeEnvironment.class);
-        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(masterNodes.get(0)));
+        logger.info("--> stop 1st cluster-manager-eligible node and data-only node");
+        NodeEnvironment nodeEnvironment = internalCluster().getClusterManagerNodeInstance(NodeEnvironment.class);
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(clusterManagerNodes.get(0)));
         assertBusy(() -> internalCluster().getInstance(GatewayMetaState.class, dataNode).allPendingAsyncStatesWritten());
         internalCluster().stopRandomDataNode();
 
-        logger.info("--> unsafely-bootstrap 1st master-eligible node");
-        MockTerminal terminal = unsafeBootstrap(environmentMaster1, false, true);
+        logger.info("--> unsafely-bootstrap 1st cluster-manager-eligible node");
+        MockTerminal terminal = unsafeBootstrap(environmentClusterManager1, false, true);
         Metadata metadata = OpenSearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, nodeEnvironment.nodeDataPaths())
             .loadBestOnDiskState().metadata;
         assertThat(
@@ -356,15 +376,15 @@ public void test3MasterNodes2Failed() throws Exception {
             containsString(
                 String.format(
                     Locale.ROOT,
-                    UnsafeBootstrapMasterCommand.CLUSTER_STATE_TERM_VERSION_MSG_FORMAT,
+                    UnsafeBootstrapClusterManagerCommand.CLUSTER_STATE_TERM_VERSION_MSG_FORMAT,
                     metadata.coordinationMetadata().term(),
                     metadata.version()
                 )
             )
         );
 
-        logger.info("--> start 1st master-eligible node");
-        String masterNode2 = internalCluster().startMasterOnlyNode(master1DataPathSettings);
+        logger.info("--> start 1st cluster-manager-eligible node");
+        String clusterManagerNode2 = internalCluster().startClusterManagerOnlyNode(clusterManager1DataPathSettings);
 
         logger.info("--> detach-cluster on data-only node");
         Environment environmentData = TestEnvironment.newEnvironment(
@@ -385,13 +405,15 @@ public void test3MasterNodes2Failed() throws Exception {
                 .execute()
                 .actionGet()
                 .getState();
-            assertFalse(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
-            assertTrue(state.metadata().persistentSettings().getAsBoolean(UnsafeBootstrapMasterCommand.UNSAFE_BOOTSTRAP.getKey(), false));
+            assertFalse(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
+            assertTrue(
+                state.metadata().persistentSettings().getAsBoolean(UnsafeBootstrapClusterManagerCommand.UNSAFE_BOOTSTRAP.getKey(), false)
+            );
         });
 
         List<String> bootstrappedNodes = new ArrayList<>();
         bootstrappedNodes.add(dataNode2);
-        bootstrappedNodes.add(masterNode2);
+        bootstrappedNodes.add(clusterManagerNode2);
         bootstrappedNodes.forEach(node -> ensureReadOnlyBlock(true, node));
 
         logger.info("--> ensure index test is green");
@@ -399,31 +421,31 @@ public void test3MasterNodes2Failed() throws Exception {
         IndexMetadata indexMetadata = clusterService().state().metadata().index("test");
         assertThat(indexMetadata.getSettings().get(IndexMetadata.SETTING_HISTORY_UUID), notNullValue());
 
-        logger.info("--> detach-cluster on 2nd and 3rd master-eligible nodes");
-        Environment environmentMaster2 = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(master2DataPathSettings).build()
+        logger.info("--> detach-cluster on 2nd and 3rd cluster-manager-eligible nodes");
+        Environment environmentClusterManager2 = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManager2DataPathSettings).build()
         );
-        detachCluster(environmentMaster2, false);
-        Environment environmentMaster3 = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(master3DataPathSettings).build()
+        detachCluster(environmentClusterManager2, false);
+        Environment environmentClusterManager3 = TestEnvironment.newEnvironment(
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManager3DataPathSettings).build()
         );
-        detachCluster(environmentMaster3, false);
+        detachCluster(environmentClusterManager3, false);
 
-        logger.info("--> start 2nd and 3rd master-eligible nodes and ensure 4 nodes stable cluster");
-        bootstrappedNodes.add(internalCluster().startMasterOnlyNode(master2DataPathSettings));
-        bootstrappedNodes.add(internalCluster().startMasterOnlyNode(master3DataPathSettings));
+        logger.info("--> start 2nd and 3rd cluster-manager-eligible nodes and ensure 4 nodes stable cluster");
+        bootstrappedNodes.add(internalCluster().startClusterManagerOnlyNode(clusterManager2DataPathSettings));
+        bootstrappedNodes.add(internalCluster().startClusterManagerOnlyNode(clusterManager3DataPathSettings));
         ensureStableCluster(4);
         bootstrappedNodes.forEach(node -> ensureReadOnlyBlock(true, node));
         removeBlock();
     }
 
-    public void testAllMasterEligibleNodesFailedDanglingIndexImport() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+    public void testAllClusterManagerEligibleNodesFailedDanglingIndexImport() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
 
         Settings settings = Settings.builder().put(AUTO_IMPORT_DANGLING_INDICES_SETTING.getKey(), true).build();
 
-        logger.info("--> start mixed data and master-eligible node and bootstrap cluster");
-        String masterNode = internalCluster().startNode(settings); // node ordinal 0
+        logger.info("--> start mixed data and cluster-manager-eligible node and bootstrap cluster");
+        String clusterManagerNode = internalCluster().startNode(settings); // node ordinal 0
 
         logger.info("--> start data-only node and ensure 2 nodes stable cluster");
         String dataNode = internalCluster().startDataOnlyNode(settings); // node ordinal 1
@@ -457,8 +479,8 @@ public void testAllMasterEligibleNodesFailedDanglingIndexImport() throws Excepti
         );
         detachCluster(environment, false);
 
-        logger.info("--> stop master-eligible node, clear its data and start it again - new cluster should form");
-        internalCluster().restartNode(masterNode, new InternalTestCluster.RestartCallback() {
+        logger.info("--> stop cluster-manager-eligible node, clear its data and start it again - new cluster should form");
+        internalCluster().restartNode(clusterManagerNode, new InternalTestCluster.RestartCallback() {
             @Override
             public boolean clearData(String nodeName) {
                 return true;
@@ -478,34 +500,34 @@ public boolean clearData(String nodeName) {
     }
 
     public void testNoInitialBootstrapAfterDetach() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        String masterNode = internalCluster().startMasterOnlyNode();
-        Settings masterNodeDataPathSettings = internalCluster().dataPathSettings(masterNode);
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        Settings clusterManagerNodeDataPathSettings = internalCluster().dataPathSettings(clusterManagerNode);
+        internalCluster().stopCurrentClusterManagerNode();
 
         final Environment environment = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(masterNodeDataPathSettings).build()
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManagerNodeDataPathSettings).build()
         );
         detachCluster(environment);
 
-        String node = internalCluster().startMasterOnlyNode(
+        String node = internalCluster().startClusterManagerOnlyNode(
             Settings.builder()
-                // give the cluster 2 seconds to elect the master (it should not)
+                // give the cluster 2 seconds to elect the cluster-manager (it should not)
                 .put(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey(), "2s")
-                .put(masterNodeDataPathSettings)
+                .put(clusterManagerNodeDataPathSettings)
                 .build()
         );
 
         ClusterState state = internalCluster().client().admin().cluster().prepareState().setLocal(true).execute().actionGet().getState();
-        assertTrue(state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID));
+        assertTrue(state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID));
 
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(node));
     }
 
     public void testCanRunUnsafeBootstrapAfterErroneousDetachWithoutLoosingMetadata() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        String masterNode = internalCluster().startMasterOnlyNode();
-        Settings masterNodeDataPathSettings = internalCluster().dataPathSettings(masterNode);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        Settings clusterManagerNodeDataPathSettings = internalCluster().dataPathSettings(clusterManagerNode);
         ClusterUpdateSettingsRequest req = new ClusterUpdateSettingsRequest().persistentSettings(
             Settings.builder().put(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey(), "1234kb")
         );
@@ -514,28 +536,28 @@ public void testCanRunUnsafeBootstrapAfterErroneousDetachWithoutLoosingMetadata(
         ClusterState state = internalCluster().client().admin().cluster().prepareState().execute().actionGet().getState();
         assertThat(state.metadata().persistentSettings().get(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey()), equalTo("1234kb"));
 
-        ensureReadOnlyBlock(false, masterNode);
+        ensureReadOnlyBlock(false, clusterManagerNode);
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
 
         final Environment environment = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(masterNodeDataPathSettings).build()
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManagerNodeDataPathSettings).build()
         );
         detachCluster(environment);
         unsafeBootstrap(environment); // read-only block will remain same as one before bootstrap, in this case it is false
 
-        String masterNode2 = internalCluster().startMasterOnlyNode(masterNodeDataPathSettings);
+        String clusterManagerNode2 = internalCluster().startClusterManagerOnlyNode(clusterManagerNodeDataPathSettings);
         ensureGreen();
-        ensureReadOnlyBlock(false, masterNode2);
+        ensureReadOnlyBlock(false, clusterManagerNode2);
 
         state = internalCluster().client().admin().cluster().prepareState().execute().actionGet().getState();
         assertThat(state.metadata().settings().get(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey()), equalTo("1234kb"));
     }
 
     public void testUnsafeBootstrapWithApplyClusterReadOnlyBlockAsFalse() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        String masterNode = internalCluster().startMasterOnlyNode();
-        Settings masterNodeDataPathSettings = internalCluster().dataPathSettings(masterNode);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        Settings clusterManagerNodeDataPathSettings = internalCluster().dataPathSettings(clusterManagerNode);
         ClusterUpdateSettingsRequest req = new ClusterUpdateSettingsRequest().persistentSettings(
             Settings.builder().put(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey(), "1234kb")
         );
@@ -544,18 +566,18 @@ public void testUnsafeBootstrapWithApplyClusterReadOnlyBlockAsFalse() throws Exc
         ClusterState state = internalCluster().client().admin().cluster().prepareState().execute().actionGet().getState();
         assertThat(state.metadata().persistentSettings().get(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey()), equalTo("1234kb"));
 
-        ensureReadOnlyBlock(false, masterNode);
+        ensureReadOnlyBlock(false, clusterManagerNode);
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
 
         final Environment environment = TestEnvironment.newEnvironment(
-            Settings.builder().put(internalCluster().getDefaultSettings()).put(masterNodeDataPathSettings).build()
+            Settings.builder().put(internalCluster().getDefaultSettings()).put(clusterManagerNodeDataPathSettings).build()
         );
         unsafeBootstrap(environment, false, false);
 
-        String masterNode2 = internalCluster().startMasterOnlyNode(masterNodeDataPathSettings);
+        String clusterManagerNode2 = internalCluster().startClusterManagerOnlyNode(clusterManagerNodeDataPathSettings);
         ensureGreen();
-        ensureReadOnlyBlock(false, masterNode2);
+        ensureReadOnlyBlock(false, clusterManagerNode2);
 
         state = internalCluster().client().admin().cluster().prepareState().execute().actionGet().getState();
         assertThat(state.metadata().settings().get(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey()), equalTo("1234kb"));
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/VotingConfigurationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/VotingConfigurationIT.java
index f73ec8dc4bcd0..de1114e152767 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/VotingConfigurationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/VotingConfigurationIT.java
@@ -62,22 +62,23 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     public void testAbdicateAfterVotingConfigExclusionAdded() throws ExecutionException, InterruptedException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         internalCluster().startNodes(2);
-        final String originalMaster = internalCluster().getMasterName();
+        final String originalClusterManager = internalCluster().getClusterManagerName();
 
-        logger.info("--> excluding master node {}", originalMaster);
-        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(originalMaster)).get();
+        logger.info("--> excluding cluster-manager node {}", originalClusterManager);
+        client().execute(AddVotingConfigExclusionsAction.INSTANCE, new AddVotingConfigExclusionsRequest(originalClusterManager)).get();
         client().admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).get();
-        assertNotEquals(originalMaster, internalCluster().getMasterName());
+        assertNotEquals(originalClusterManager, internalCluster().getClusterManagerName());
     }
 
     public void testElectsNodeNotInVotingConfiguration() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         final List<String> nodeNames = internalCluster().startNodes(4);
 
         // a 4-node cluster settles on a 3-node configuration; we then prevent the nodes in the configuration from winning an election
-        // by failing at the pre-voting stage, so that the extra node must be elected instead when the master shuts down. This extra node
+        // by failing at the pre-voting stage, so that the extra node must be elected instead when the cluster-manager shuts down. This
+        // extra node
         // should then add itself into the voting configuration.
 
         assertFalse(
@@ -104,7 +105,7 @@ public void testElectsNodeNotInVotingConfiguration() throws Exception {
         final Set<String> votingConfiguration = clusterState.getLastCommittedConfiguration().getNodeIds();
         assertThat(votingConfiguration, hasSize(3));
         assertThat(clusterState.nodes().getSize(), equalTo(4));
-        assertThat(votingConfiguration, hasItem(clusterState.nodes().getMasterNodeId()));
+        assertThat(votingConfiguration, hasItem(clusterState.nodes().getClusterManagerNodeId()));
         for (DiscoveryNode discoveryNode : clusterState.nodes()) {
             if (votingConfiguration.contains(discoveryNode.getId()) == false) {
                 assertThat(excludedNodeName, nullValue());
@@ -133,7 +134,7 @@ public void testElectsNodeNotInVotingConfiguration() throws Exception {
             }
         }
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
         assertFalse(
             internalCluster().client()
                 .admin()
@@ -154,7 +155,10 @@ public void testElectsNodeNotInVotingConfiguration() throws Exception {
             .setMetadata(true)
             .get()
             .getState();
-        assertThat(newClusterState.nodes().getMasterNode().getName(), equalTo(excludedNodeName));
-        assertThat(newClusterState.getLastCommittedConfiguration().getNodeIds(), hasItem(newClusterState.nodes().getMasterNodeId()));
+        assertThat(newClusterState.nodes().getClusterManagerNode().getName(), equalTo(excludedNodeName));
+        assertThat(
+            newClusterState.getLastCommittedConfiguration().getNodeIds(),
+            hasItem(newClusterState.nodes().getClusterManagerNodeId())
+        );
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/ZenDiscoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/ZenDiscoveryIT.java
index 1baac9071110a..9bddb39e79484 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/ZenDiscoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/coordination/ZenDiscoveryIT.java
@@ -42,9 +42,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.discovery.DiscoveryStats;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -59,8 +59,8 @@
 import java.util.concurrent.TimeoutException;
 
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.DISCOVERY;
+import static org.opensearch.test.NodeRoles.clusterManagerOnlyNode;
 import static org.opensearch.test.NodeRoles.dataNode;
-import static org.opensearch.test.NodeRoles.masterOnlyNode;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
@@ -71,10 +71,10 @@
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
 public class ZenDiscoveryIT extends OpenSearchIntegTestCase {
 
-    public void testNoShardRelocationsOccurWhenElectedMasterNodeFails() throws Exception {
+    public void testNoShardRelocationsOccurWhenElectedClusterManagerNodeFails() throws Exception {
 
-        Settings masterNodeSettings = masterOnlyNode();
-        internalCluster().startNodes(2, masterNodeSettings);
+        Settings clusterManagerNodeSettings = clusterManagerOnlyNode();
+        internalCluster().startNodes(2, clusterManagerNodeSettings);
         Settings dateNodeSettings = dataNode();
         internalCluster().startNodes(2, dateNodeSettings);
         ClusterHealthResponse clusterHealthResponse = client().admin()
@@ -89,27 +89,27 @@ public void testNoShardRelocationsOccurWhenElectedMasterNodeFails() throws Excep
         createIndex("test");
         ensureSearchable("test");
         RecoveryResponse r = client().admin().indices().prepareRecoveries("test").get();
-        int numRecoveriesBeforeNewMaster = r.shardRecoveryStates().get("test").size();
+        int numRecoveriesBeforeNewClusterManager = r.shardRecoveryStates().get("test").size();
 
-        final String oldMaster = internalCluster().getMasterName();
-        internalCluster().stopCurrentMasterNode();
+        final String oldClusterManager = internalCluster().getClusterManagerName();
+        internalCluster().stopCurrentClusterManagerNode();
         assertBusy(() -> {
-            String current = internalCluster().getMasterName();
+            String current = internalCluster().getClusterManagerName();
             assertThat(current, notNullValue());
-            assertThat(current, not(equalTo(oldMaster)));
+            assertThat(current, not(equalTo(oldClusterManager)));
         });
         ensureSearchable("test");
 
         r = client().admin().indices().prepareRecoveries("test").get();
-        int numRecoveriesAfterNewMaster = r.shardRecoveryStates().get("test").size();
-        assertThat(numRecoveriesAfterNewMaster, equalTo(numRecoveriesBeforeNewMaster));
+        int numRecoveriesAfterNewClusterManager = r.shardRecoveryStates().get("test").size();
+        assertThat(numRecoveriesAfterNewClusterManager, equalTo(numRecoveriesBeforeNewClusterManager));
     }
 
     public void testHandleNodeJoin_incompatibleClusterState() throws InterruptedException, ExecutionException, TimeoutException {
-        String masterNode = internalCluster().startMasterOnlyNode();
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         String node1 = internalCluster().startNode();
         ClusterService clusterService = internalCluster().getInstance(ClusterService.class, node1);
-        Coordinator coordinator = (Coordinator) internalCluster().getInstance(Discovery.class, masterNode);
+        Coordinator coordinator = (Coordinator) internalCluster().getInstance(Discovery.class, clusterManagerNode);
         final ClusterState state = clusterService.state();
         Metadata.Builder mdBuilder = Metadata.builder(state.metadata());
         mdBuilder.putCustom(CustomMetadata.TYPE, new CustomMetadata("data"));
@@ -170,7 +170,9 @@ public void testDiscoveryStats() throws Exception {
         ensureGreen(); // ensures that all events are processed (in particular state recovery fully completed)
         assertBusy(
             () -> assertThat(
-                internalCluster().clusterService(internalCluster().getMasterName()).getMasterService().numberOfPendingTasks(),
+                internalCluster().clusterService(internalCluster().getClusterManagerName())
+                    .getClusterManagerService()
+                    .numberOfPendingTasks(),
                 equalTo(0)
             )
         ); // see https://github.com/elastic/elasticsearch/issues/24388
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalIT.java
new file mode 100644
index 0000000000000..54824b67b7abc
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalIT.java
@@ -0,0 +1,338 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.action.admin.indices.get.GetIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexResponse;
+import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.indices.IndicesService.CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class ClusterIndexRefreshIntervalIT extends OpenSearchIntegTestCase {
+
+    public static final String INDEX_NAME = "test-index";
+
+    public static final String OTHER_INDEX_NAME = "other-test-index";
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder().put(super.indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1).build();
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        internalCluster().startClusterManagerOnlyNode();
+    }
+
+    public void testDefaultRefreshIntervalWithUpdateClusterAndIndexSettings() throws Exception {
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        GetIndexResponse getIndexResponse = client(clusterManagerName).admin().indices().getIndex(new GetIndexRequest()).get();
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, randomFrom(dataNodes));
+        String uuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+        IndexService indexService = indicesService.indexService(new Index(INDEX_NAME, uuid));
+        assertEquals(getDefaultRefreshInterval(), indexService.getRefreshTaskInterval());
+
+        // Update the cluster.default.index.refresh_interval setting to another value and validate the index refresh interval
+        TimeValue refreshInterval = TimeValue.timeValueMillis(randomIntBetween(10, 90) * 1000L);
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), refreshInterval))
+            .get();
+        assertEquals(refreshInterval, indexService.getRefreshTaskInterval());
+
+        // Update of cluster.minimum.index.refresh_interval setting to value less than refreshInterval above will fail
+        TimeValue invalidMinimumRefreshInterval = TimeValue.timeValueMillis(refreshInterval.millis() + randomIntBetween(1, 1000));
+        IllegalArgumentException exceptionDuringMinUpdate = assertThrows(
+            IllegalArgumentException.class,
+            () -> client(clusterManagerName).admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(
+                    Settings.builder().put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), invalidMinimumRefreshInterval)
+                )
+                .get()
+        );
+        assertEquals(
+            "cluster minimum index refresh interval ["
+                + invalidMinimumRefreshInterval
+                + "] more than cluster default index refresh interval ["
+                + refreshInterval
+                + "]",
+            exceptionDuringMinUpdate.getMessage()
+        );
+
+        // Update the cluster.minimum.index.refresh_interval setting to a valid value, this will succeed.
+        TimeValue validMinimumRefreshInterval = TimeValue.timeValueMillis(refreshInterval.millis() - randomIntBetween(1, 1000));
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(
+                Settings.builder().put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), validMinimumRefreshInterval)
+            )
+            .get();
+
+        // Update with invalid index setting index.refresh_interval, this will fail.
+        TimeValue invalidRefreshInterval = TimeValue.timeValueMillis(validMinimumRefreshInterval.millis() - randomIntBetween(1, 1000));
+        String expectedMessage = "invalid index.refresh_interval ["
+            + invalidRefreshInterval
+            + "]: cannot be smaller than cluster.minimum.index.refresh_interval ["
+            + validMinimumRefreshInterval
+            + "]";
+
+        IllegalArgumentException exceptionDuringUpdateSettings = assertThrows(
+            IllegalArgumentException.class,
+            () -> client(clusterManagerName).admin()
+                .indices()
+                .updateSettings(
+                    new UpdateSettingsRequest(INDEX_NAME).settings(
+                        Settings.builder().put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), invalidRefreshInterval)
+                    )
+                )
+                .actionGet()
+        );
+        assertEquals(expectedMessage, exceptionDuringUpdateSettings.getMessage());
+
+        // Create another index with invalid index setting index.refresh_interval, this fails.
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), invalidRefreshInterval)
+            .build();
+        IllegalArgumentException exceptionDuringCreateIndex = assertThrows(
+            IllegalArgumentException.class,
+            () -> createIndex(OTHER_INDEX_NAME, indexSettings)
+        );
+        assertEquals(expectedMessage, exceptionDuringCreateIndex.getMessage());
+
+        // Update with valid index setting index.refresh_interval, this will succeed now.
+        TimeValue validRefreshInterval = TimeValue.timeValueMillis(validMinimumRefreshInterval.millis() + randomIntBetween(1, 1000));
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), validRefreshInterval)
+                )
+            )
+            .get();
+        // verify refresh task interval is updated.
+        assertEquals(validRefreshInterval, indexService.getRefreshTaskInterval());
+
+        // Try to create another index with valid index setting index.refresh_interval, this will pass.
+        createIndex(
+            OTHER_INDEX_NAME,
+            Settings.builder().put(indexSettings).put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), validRefreshInterval).build()
+        );
+        getIndexResponse = client(clusterManagerName).admin().indices().getIndex(new GetIndexRequest()).get();
+        String otherUuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+        assertEquals(validRefreshInterval, indicesService.indexService(new Index(OTHER_INDEX_NAME, otherUuid)).getRefreshTaskInterval());
+
+        // Update the cluster.default.index.refresh_interval & cluster.minimum.index.refresh_interval setting to null
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(
+                Settings.builder()
+                    .putNull(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey())
+                    .putNull(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey())
+            )
+            .get();
+        // verify the index is still using the refresh interval passed in the update settings call
+        assertEquals(validRefreshInterval, indexService.getRefreshTaskInterval());
+
+        // Remove the index setting as well now, it should reset the refresh task interval to the default refresh interval
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().putNull(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey())
+                )
+            )
+            .get();
+        assertEquals(getDefaultRefreshInterval(), indexService.getRefreshTaskInterval());
+    }
+
+    public void testRefreshIntervalDisabled() throws ExecutionException, InterruptedException {
+        TimeValue clusterMinimumRefreshInterval = client().settings()
+            .getAsTime(IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), TimeValue.MINUS_ONE);
+        boolean createIndexSuccess = clusterMinimumRefreshInterval.equals(TimeValue.MINUS_ONE);
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
+        Settings settings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), IndexSettings.MINIMUM_REFRESH_INTERVAL)
+            .build();
+        if (createIndexSuccess) {
+            createIndex(INDEX_NAME, settings);
+            ensureYellowAndNoInitializingShards(INDEX_NAME);
+            ensureGreen(INDEX_NAME);
+            GetIndexResponse getIndexResponse = client(clusterManagerName).admin().indices().getIndex(new GetIndexRequest()).get();
+            IndicesService indicesService = internalCluster().getInstance(IndicesService.class, randomFrom(dataNodes));
+            String uuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+            IndexService indexService = indicesService.indexService(new Index(INDEX_NAME, uuid));
+            assertEquals(IndexSettings.MINIMUM_REFRESH_INTERVAL, indexService.getRefreshTaskInterval());
+        } else {
+            IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> createIndex(INDEX_NAME, settings));
+            assertEquals(
+                "invalid index.refresh_interval [-1]: cannot be smaller than cluster.minimum.index.refresh_interval ["
+                    + getMinRefreshIntervalForRefreshDisabled()
+                    + "]",
+                exception.getMessage()
+            );
+        }
+    }
+
+    protected TimeValue getMinRefreshIntervalForRefreshDisabled() {
+        throw new RuntimeException("This is not expected to be called here, but for the implementor");
+    }
+
+    public void testInvalidRefreshInterval() {
+        String invalidRefreshInterval = "-10s";
+        internalCluster().startDataOnlyNodes(2);
+        Settings settings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), invalidRefreshInterval)
+            .build();
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> createIndex(INDEX_NAME, settings));
+        assertEquals(
+            "failed to parse setting [index.refresh_interval] with value ["
+                + invalidRefreshInterval
+                + "] as a time value: negative durations are not supported",
+            exception.getMessage()
+        );
+    }
+
+    public void testCreateIndexWithExplicitNullRefreshInterval() throws ExecutionException, InterruptedException {
+        List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .putNull(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey())
+            .build();
+        createIndex(INDEX_NAME, indexSettings);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        GetIndexResponse getIndexResponse = client(internalCluster().getClusterManagerName()).admin()
+            .indices()
+            .getIndex(new GetIndexRequest())
+            .get();
+        String uuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, randomFrom(dataNodes));
+        IndexService indexService = indicesService.indexService(new Index(INDEX_NAME, uuid));
+
+        assertEquals(IndexSettings.DEFAULT_REFRESH_INTERVAL, indexService.getRefreshTaskInterval());
+    }
+
+    /**
+     * In this test we check the case where an index is created with index setting `index.refresh_interval` with the value
+     * being lesser than the `cluster.minimum.index.refresh_interval`. Later we change the cluster minimum to be more than
+     * the index setting. The underlying index should continue to use the same refresh interval as earlier.
+     */
+    public void testClusterMinimumChangeOnIndexWithCustomRefreshInterval() throws ExecutionException, InterruptedException {
+        List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
+        TimeValue customRefreshInterval = TimeValue.timeValueSeconds(getDefaultRefreshInterval().getSeconds() + randomIntBetween(1, 5));
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), customRefreshInterval)
+            .build();
+        createIndex(INDEX_NAME, indexSettings);
+
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        GetIndexResponse getIndexResponse = client(internalCluster().getClusterManagerName()).admin()
+            .indices()
+            .getIndex(new GetIndexRequest())
+            .get();
+        String uuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, randomFrom(dataNodes));
+        IndexService indexService = indicesService.indexService(new Index(INDEX_NAME, uuid));
+
+        assertEquals(customRefreshInterval, indexService.getRefreshTaskInterval());
+
+        // Update the cluster.minimum.index.refresh_interval setting to a valid value higher the custom refresh interval.
+        // At the same time, due to certain degree of randomness in the test, we update the cluster.default.refresh_interval
+        // to a valid value as well to be deterministic in test behaviour.
+        TimeValue clusterMinimum = TimeValue.timeValueSeconds(customRefreshInterval.getSeconds() + randomIntBetween(1, 5));
+        TimeValue clusterDefault = TimeValue.timeValueSeconds(customRefreshInterval.getSeconds() + 6);
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(
+                Settings.builder()
+                    .put(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterDefault)
+                    .put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterMinimum)
+            )
+            .get();
+
+        // Validate that the index refresh interval is still the existing one that was used during index creation
+        assertEquals(customRefreshInterval, indexService.getRefreshTaskInterval());
+
+        // Update index setting to a value >= current cluster minimum and this should happen successfully.
+        customRefreshInterval = TimeValue.timeValueSeconds(clusterMinimum.getSeconds() + randomIntBetween(1, 5));
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), customRefreshInterval)
+                )
+            )
+            .get();
+        assertEquals(customRefreshInterval, indexService.getRefreshTaskInterval());
+    }
+
+    protected TimeValue getDefaultRefreshInterval() {
+        return IndexSettings.DEFAULT_REFRESH_INTERVAL;
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalWithNodeSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalWithNodeSettingsIT.java
new file mode 100644
index 0000000000000..5fc7bfcbcd442
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/ClusterIndexRefreshIntervalWithNodeSettingsIT.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.indices.IndicesService;
+
+public class ClusterIndexRefreshIntervalWithNodeSettingsIT extends ClusterIndexRefreshIntervalIT {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(IndicesService.CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), getDefaultRefreshInterval())
+            .put(
+                IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(),
+                getMinRefreshIntervalForRefreshDisabled().toString()
+            )
+            .build();
+    }
+
+    @Override
+    protected TimeValue getMinRefreshIntervalForRefreshDisabled() {
+        return TimeValue.timeValueSeconds(1);
+    }
+
+    @Override
+    protected TimeValue getDefaultRefreshInterval() {
+        return TimeValue.timeValueSeconds(5);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceIT.java
index babe228f544a9..ba1679d873bf4 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceIT.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.plugins.Plugin;
@@ -99,11 +99,9 @@ public Collection<Object> createComponents(
             IndexNameExpressionResolver expressionResolver,
             Supplier<RepositoriesService> repositoriesServiceSupplier
         ) {
-            clusterService.getClusterSettings()
-                .addSettingsUpdateConsumer(
-                    UPDATE_TEMPLATE_DUMMY_SETTING,
-                    integer -> { logger.debug("the template dummy setting was updated to {}", integer); }
-                );
+            clusterService.getClusterSettings().addSettingsUpdateConsumer(UPDATE_TEMPLATE_DUMMY_SETTING, integer -> {
+                logger.debug("the template dummy setting was updated to {}", integer);
+            });
             return super.createComponents(
                 client,
                 clusterService,
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/node/DiscoveryNodeRoleIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/node/DiscoveryNodeRoleIT.java
index 4e30a7f6130fb..8c0eb891475cc 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/node/DiscoveryNodeRoleIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/node/DiscoveryNodeRoleIT.java
@@ -38,7 +38,6 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
 import org.hamcrest.Matcher;
 
 import java.util.Collection;
@@ -47,10 +46,12 @@
 import java.util.Set;
 
 import static org.opensearch.test.NodeRoles.addRoles;
+import static org.opensearch.test.NodeRoles.onlyRole;
 import static org.opensearch.test.NodeRoles.removeRoles;
 import static org.hamcrest.Matchers.hasItem;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.startsWith;
 
 public class DiscoveryNodeRoleIT extends OpenSearchIntegTestCase {
 
@@ -126,4 +127,18 @@ private void runTestNodeHasAdditionalRole(final Settings settings) {
         assertThat(response.getNodes().get(0).getNode().getRoles(), matcher);
     }
 
+    public void testStartNodeWithClusterManagerRoleAndMasterSetting() {
+        final Settings settings = Settings.builder()
+            .put("node.master", randomBoolean())
+            .put(onlyRole(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+            .build();
+
+        final IllegalArgumentException e1 = expectThrows(
+            IllegalArgumentException.class,
+            () -> DiscoveryNode.getRolesFromSettings(settings)
+        );
+        assertThat(e1.getMessage(), startsWith("can not explicitly configure node roles and use legacy role setting"));
+        final IllegalArgumentException e2 = expectThrows(IllegalArgumentException.class, () -> internalCluster().startNodes(settings));
+        assertThat(e2.getMessage(), startsWith("can not explicitly configure node roles and use legacy role setting"));
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/AllocationIdIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/AllocationIdIT.java
index a20e944caebb2..82159065bcc8a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/AllocationIdIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/AllocationIdIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.cluster.routing;
 
 import org.apache.lucene.store.NIOFSDirectory;
-
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplanation;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -45,20 +44,20 @@
 import org.opensearch.cluster.routing.allocation.ShardAllocationDecision;
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.RemoveCorruptedShardDataCommandIT;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.Store;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 
 import java.io.IOException;
@@ -100,7 +99,7 @@ public void testFailedRecoveryOnAllocateStalePrimaryRequiresAnotherAllocateStale
 
         // initial set up
         final String indexName = "index42";
-        final String master = internalCluster().startMasterOnlyNode();
+        final String clusterManager = internalCluster().startClusterManagerOnlyNode();
         String node1 = internalCluster().startNode();
         createIndex(
             indexName,
@@ -135,7 +134,7 @@ public void testFailedRecoveryOnAllocateStalePrimaryRequiresAnotherAllocateStale
         // create fake corrupted marker on node1
         putFakeCorruptionMarker(indexSettings, shardId, indexPath);
 
-        // thanks to master node1 is out of sync
+        // thanks to cluster-manager node1 is out of sync
         node1 = internalCluster().startNode(node1DataPathSettings);
 
         // there is only _stale_ primary
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/DelayedAllocationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/DelayedAllocationIT.java
index b4b08a4c9ad73..45c72eefa2285 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/DelayedAllocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/DelayedAllocationIT.java
@@ -37,8 +37,8 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Collections;
 import java.util.List;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/PrimaryAllocationIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/PrimaryAllocationIT.java
index 55bdc2a4ac3c4..0dd5f036457ad 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/PrimaryAllocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/PrimaryAllocationIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteRequestBuilder;
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresResponse;
@@ -47,22 +46,22 @@
 import org.opensearch.cluster.routing.allocation.command.AllocateEmptyPrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineTestCase;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.disruption.NetworkDisruption;
 import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
 import org.opensearch.test.transport.MockTransportService;
@@ -73,6 +72,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
@@ -110,7 +110,7 @@ protected boolean addMockInternalEngine() {
     }
 
     public void testBulkWeirdScenario() throws Exception {
-        String master = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNodes(2);
 
         assertAcked(
@@ -136,7 +136,7 @@ public void testBulkWeirdScenario() throws Exception {
         assertThat(bulkResponse.hasFailures(), equalTo(false));
         assertThat(bulkResponse.getItems().length, equalTo(2));
 
-        logger.info(Strings.toString(bulkResponse, true, true));
+        logger.info(Strings.toString(MediaTypeRegistry.JSON, bulkResponse, true, true));
 
         internalCluster().assertSeqNos();
 
@@ -149,7 +149,7 @@ public void testBulkWeirdScenario() throws Exception {
     }
 
     // returns data paths settings of in-sync shard copy
-    private Settings createStaleReplicaScenario(String master) throws Exception {
+    private Settings createStaleReplicaScenario(String clusterManager) throws Exception {
         client().prepareIndex("test").setSource(jsonBuilder().startObject().field("field", "value1").endObject()).get();
         refresh();
         ClusterState state = client().admin().cluster().prepareState().all().get().getState();
@@ -167,14 +167,14 @@ private Settings createStaleReplicaScenario(String master) throws Exception {
         }
 
         NetworkDisruption partition = new NetworkDisruption(
-            new TwoPartitions(Sets.newHashSet(master, replicaNode), Collections.singleton(primaryNode)),
+            new TwoPartitions(Sets.newHashSet(clusterManager, replicaNode), Collections.singleton(primaryNode)),
             NetworkDisruption.DISCONNECT
         );
         internalCluster().setDisruptionScheme(partition);
         logger.info("--> partitioning node with primary shard from rest of cluster");
         partition.startDisrupting();
 
-        ensureStableCluster(2, master);
+        ensureStableCluster(2, clusterManager);
 
         logger.info("--> index a document into previous replica shard (that is now primary)");
         client(replicaNode).prepareIndex("test").setSource(jsonBuilder().startObject().field("field", "value1").endObject()).get();
@@ -183,27 +183,30 @@ private Settings createStaleReplicaScenario(String master) throws Exception {
         final Settings inSyncDataPathSettings = internalCluster().dataPathSettings(replicaNode);
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(replicaNode));
 
-        ensureStableCluster(1, master);
+        ensureStableCluster(1, clusterManager);
 
         partition.stopDisrupting();
 
         logger.info("--> waiting for node with old primary shard to rejoin the cluster");
-        ensureStableCluster(2, master);
+        ensureStableCluster(2, clusterManager);
 
         logger.info("--> check that old primary shard does not get promoted to primary again");
         // kick reroute and wait for all shard states to be fetched
-        client(master).admin().cluster().prepareReroute().get();
+        client(clusterManager).admin().cluster().prepareReroute().get();
         assertBusy(
-            () -> assertThat(internalCluster().getInstance(GatewayAllocator.class, master).getNumberOfInFlightFetches(), equalTo(0))
+            () -> assertThat(internalCluster().getInstance(GatewayAllocator.class, clusterManager).getNumberOfInFlightFetches(), equalTo(0))
         );
         // kick reroute a second time and check that all shards are unassigned
-        assertThat(client(master).admin().cluster().prepareReroute().get().getState().getRoutingNodes().unassigned().size(), equalTo(2));
+        assertThat(
+            client(clusterManager).admin().cluster().prepareReroute().get().getState().getRoutingNodes().unassigned().size(),
+            equalTo(2)
+        );
         return inSyncDataPathSettings;
     }
 
     public void testDoNotAllowStaleReplicasToBePromotedToPrimary() throws Exception {
-        logger.info("--> starting 3 nodes, 1 master, 2 data");
-        String master = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        logger.info("--> starting 3 nodes, 1 cluster-manager, 2 data");
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNodes(2);
         assertAcked(
             client().admin()
@@ -213,7 +216,7 @@ public void testDoNotAllowStaleReplicasToBePromotedToPrimary() throws Exception
                 .get()
         );
         ensureGreen();
-        final Settings inSyncDataPathSettings = createStaleReplicaScenario(master);
+        final Settings inSyncDataPathSettings = createStaleReplicaScenario(clusterManager);
 
         logger.info("--> starting node that reuses data folder with the up-to-date primary shard");
         internalCluster().startDataOnlyNode(inSyncDataPathSettings);
@@ -291,8 +294,8 @@ public void testFailedAllocationOfStalePrimaryToDataNodeWithNoData() throws Exce
     }
 
     public void testForceStaleReplicaToBePromotedToPrimary() throws Exception {
-        logger.info("--> starting 3 nodes, 1 master, 2 data");
-        String master = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        logger.info("--> starting 3 nodes, 1 cluster-manager, 2 data");
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNodes(2);
         assertAcked(
             client().admin()
@@ -305,23 +308,23 @@ public void testForceStaleReplicaToBePromotedToPrimary() throws Exception {
         Set<String> historyUUIDs = Arrays.stream(client().admin().indices().prepareStats("test").clear().get().getShards())
             .map(shard -> shard.getCommitStats().getUserData().get(Engine.HISTORY_UUID_KEY))
             .collect(Collectors.toSet());
-        createStaleReplicaScenario(master);
+        createStaleReplicaScenario(clusterManager);
         if (randomBoolean()) {
             assertAcked(client().admin().indices().prepareClose("test").setWaitForActiveShards(0));
         }
         boolean useStaleReplica = randomBoolean(); // if true, use stale replica, otherwise a completely empty copy
         logger.info("--> explicitly promote old primary shard");
         final String idxName = "test";
-        ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> storeStatuses = client().admin()
+        final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> storeStatuses = client().admin()
             .indices()
             .prepareShardStores(idxName)
             .get()
             .getStoreStatuses()
             .get(idxName);
         ClusterRerouteRequestBuilder rerouteBuilder = client().admin().cluster().prepareReroute();
-        for (IntObjectCursor<List<IndicesShardStoresResponse.StoreStatus>> shardStoreStatuses : storeStatuses) {
-            int shardId = shardStoreStatuses.key;
-            IndicesShardStoresResponse.StoreStatus storeStatus = randomFrom(shardStoreStatuses.value);
+        for (var shardStoreStatuses : storeStatuses.entrySet()) {
+            int shardId = shardStoreStatuses.getKey();
+            IndicesShardStoresResponse.StoreStatus storeStatus = randomFrom(shardStoreStatuses.getValue());
             logger.info("--> adding allocation command for shard {}", shardId);
             // force allocation based on node id
             if (useStaleReplica) {
@@ -343,7 +346,7 @@ public void testForceStaleReplicaToBePromotedToPrimary() throws Exception {
             }
             logger.info("expected allocation ids: {} actual allocation ids: {}", expectedAllocationIds, allocationIds);
         };
-        final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, master);
+        final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, clusterManager);
         clusterService.addListener(clusterStateListener);
 
         rerouteBuilder.get();
@@ -390,7 +393,7 @@ public void testForceStaleReplicaToBePromotedToPrimary() throws Exception {
     }
 
     public void testForceStaleReplicaToBePromotedToPrimaryOnWrongNode() throws Exception {
-        String master = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNodes(2);
         final String idxName = "test";
         assertAcked(
@@ -401,14 +404,14 @@ public void testForceStaleReplicaToBePromotedToPrimaryOnWrongNode() throws Excep
                 .get()
         );
         ensureGreen();
-        createStaleReplicaScenario(master);
+        createStaleReplicaScenario(clusterManager);
         // Ensure the stopped primary's data is deleted so that it doesn't get picked up by the next datanode we start
         internalCluster().wipePendingDataDirectories();
         internalCluster().startDataOnlyNodes(1);
-        ensureStableCluster(3, master);
+        ensureStableCluster(3, clusterManager);
         final int shardId = 0;
         final List<String> nodeNames = new ArrayList<>(Arrays.asList(internalCluster().getNodeNames()));
-        nodeNames.remove(master);
+        nodeNames.remove(clusterManager);
         client().admin()
             .indices()
             .prepareShardStores(idxName)
@@ -434,7 +437,7 @@ public void testForceStaleReplicaToBePromotedToPrimaryOnWrongNode() throws Excep
     }
 
     public void testForceStaleReplicaToBePromotedForGreenIndex() {
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         final List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
         final String idxName = "test";
         assertAcked(
@@ -459,7 +462,7 @@ public void testForceStaleReplicaToBePromotedForGreenIndex() {
     }
 
     public void testForceStaleReplicaToBePromotedForMissingIndex() {
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String idxName = "test";
         IndexNotFoundException ex = expectThrows(
@@ -497,7 +500,7 @@ public void testForcePrimaryShardIfAllocationDecidersSayNoAfterIndexCreation() t
     }
 
     public void testDoNotRemoveAllocationIdOnNodeLeave() throws Exception {
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNode(Settings.EMPTY);
         assertAcked(
             client().admin()
@@ -537,7 +540,7 @@ public boolean clearData(String nodeName) {
     }
 
     public void testRemoveAllocationIdOnWriteAfterNodeLeave() throws Exception {
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNode(Settings.EMPTY);
         assertAcked(
             client().admin()
@@ -657,7 +660,7 @@ public void testForceAllocatePrimaryOnNoDecision() throws Exception {
      * This test asserts that replicas failed to execute resync operations will be failed but not marked as stale.
      */
     public void testPrimaryReplicaResyncFailed() throws Exception {
-        String master = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         final int numberOfReplicas = between(2, 3);
         final String oldPrimary = internalCluster().startDataOnlyNode();
         assertAcked(
@@ -671,7 +674,7 @@ public void testPrimaryReplicaResyncFailed() throws Exception {
         ensureGreen();
         String timeout = randomFrom("0s", "1s", "2s");
         assertAcked(
-            client(master).admin()
+            client(clusterManager).admin()
                 .cluster()
                 .prepareUpdateSettings()
                 .setTransientSettings(Settings.builder().put("cluster.routing.allocation.enable", "none"))
@@ -700,7 +703,7 @@ public void testPrimaryReplicaResyncFailed() throws Exception {
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(oldPrimary));
         // Checks that we fails replicas in one side but not mark them as stale.
         assertBusy(() -> {
-            ClusterState state = client(master).admin().cluster().prepareState().get().getState();
+            ClusterState state = client(clusterManager).admin().cluster().prepareState().get().getState();
             final IndexShardRoutingTable shardRoutingTable = state.routingTable().shardRoutingTable(shardId);
             final String newPrimaryNode = state.getRoutingNodes().node(shardRoutingTable.primary.currentNodeId()).node().getName();
             assertThat(newPrimaryNode, not(equalTo(oldPrimary)));
@@ -712,7 +715,7 @@ public void testPrimaryReplicaResyncFailed() throws Exception {
             assertThat(state.metadata().index("test").inSyncAllocationIds(shardId.id()), hasSize(numberOfReplicas + 1));
         }, 1, TimeUnit.MINUTES);
         assertAcked(
-            client(master).admin()
+            client(clusterManager).admin()
                 .cluster()
                 .prepareUpdateSettings()
                 .setTransientSettings(Settings.builder().put("cluster.routing.allocation.enable", "all"))
@@ -722,7 +725,7 @@ public void testPrimaryReplicaResyncFailed() throws Exception {
         partition.ensureHealthy(internalCluster());
         logger.info("--> stop disrupting network and re-enable allocation");
         assertBusy(() -> {
-            ClusterState state = client(master).admin().cluster().prepareState().get().getState();
+            ClusterState state = client(clusterManager).admin().cluster().prepareState().get().getState();
             assertThat(state.routingTable().shardRoutingTable(shardId).activeShards(), hasSize(numberOfReplicas));
             assertThat(state.metadata().index("test").inSyncAllocationIds(shardId.id()), hasSize(numberOfReplicas + 1));
             for (String node : replicaNodes) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/WeightedRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/WeightedRoutingIT.java
new file mode 100644
index 0000000000000..2e0dd579d6910
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/WeightedRoutingIT.java
@@ -0,0 +1,718 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.ResourceNotFoundException;
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
+import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.snapshots.mockstore.MockRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, minNumDataNodes = 3)
+public class WeightedRoutingIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class, MockRepository.Plugin.class);
+    }
+
+    public void testPutWeightedRouting() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> starting 6 nodes on different zones");
+        int nodeCountPerAZ = 2;
+
+        logger.info("--> starting a dedicated cluster manager node");
+        internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 1 nodes on zones 'a' & 'b' & 'c'");
+        List<String> nodes_in_zone_a = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        List<String> nodes_in_zone_b = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        List<String> nodes_in_zone_c = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("7").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        // put call made on a data node in zone a
+        response = internalCluster().client(randomFrom(nodes_in_zone_a.get(0), nodes_in_zone_a.get(1)))
+            .admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(0)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+    }
+
+    public void testPutWeightedRouting_InvalidAwarenessAttribute() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone1", weights);
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().cluster().prepareWeightedRouting().setWeightedRouting(weightedRouting).get()
+        );
+    }
+
+    public void testPutWeightedRouting_MoreThanOneZoneHasZeroWeight() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 0.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone1", weights);
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().cluster().prepareWeightedRouting().setWeightedRouting(weightedRouting).get()
+        );
+    }
+
+    public void testGetWeightedRouting_WeightsNotSet() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        ClusterGetWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .get();
+        assertNull(weightedRoutingResponse.weights());
+        assertNull(weightedRoutingResponse.getDiscoveredClusterManager());
+    }
+
+    public void testGetWeightedRouting_WeightsAreSet() throws IOException {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        int nodeCountPerAZ = 2;
+
+        logger.info("--> starting a dedicated cluster manager node");
+        internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 2 nodes on zones 'a' & 'b' & 'c'");
+        List<String> nodes_in_zone_a = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        List<String> nodes_in_zone_b = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        List<String> nodes_in_zone_c = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("7").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        // put api call to set weights
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        // get api call to fetch weights
+        ClusterGetWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .get();
+        assertEquals(weightedRouting, weightedRoutingResponse.weights());
+        assertTrue(weightedRoutingResponse.getDiscoveredClusterManager());
+
+        // get api to fetch local weighted routing for a node in zone a
+        weightedRoutingResponse = internalCluster().client(randomFrom(nodes_in_zone_a.get(0), nodes_in_zone_a.get(1)))
+            .admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .setRequestLocal(true)
+            .get();
+        assertEquals(weightedRouting, weightedRoutingResponse.weights());
+        assertTrue(weightedRoutingResponse.getDiscoveredClusterManager());
+
+        // get api to fetch local weighted routing for a node in zone b
+        weightedRoutingResponse = internalCluster().client(randomFrom(nodes_in_zone_b.get(0), nodes_in_zone_b.get(1)))
+            .admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .setRequestLocal(true)
+            .get();
+        assertEquals(weightedRouting, weightedRoutingResponse.weights());
+        assertTrue(weightedRoutingResponse.getDiscoveredClusterManager());
+
+        // get api to fetch local weighted routing for a node in zone c
+        weightedRoutingResponse = internalCluster().client(randomFrom(nodes_in_zone_c.get(0), nodes_in_zone_c.get(1)))
+            .admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .setRequestLocal(true)
+            .get();
+        assertEquals(weightedRouting, weightedRoutingResponse.weights());
+        assertTrue(weightedRoutingResponse.getDiscoveredClusterManager());
+
+    }
+
+    public void testGetWeightedRouting_ClusterManagerNotDiscovered() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.fault_detection.leader_check.timeout", 10000 + "ms")
+            .put("cluster.fault_detection.leader_check.retry_count", 1)
+            .build();
+
+        int nodeCountPerAZ = 1;
+
+        logger.info("--> starting a dedicated cluster manager node");
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 2 nodes on zones 'a' & 'b' & 'c'");
+        List<String> nodes_in_zone_a = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        List<String> nodes_in_zone_b = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        List<String> nodes_in_zone_c = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("4").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        // put api call to set weights
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        Set<String> nodesInOneSide = Stream.of(nodes_in_zone_a.get(0), nodes_in_zone_b.get(0), nodes_in_zone_c.get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(clusterManager).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        // wait for leader checker to fail
+        Thread.sleep(13000);
+
+        // get api to fetch local weighted routing for a node in zone a or b
+        ClusterGetWeightedRoutingResponse weightedRoutingResponse = internalCluster().client(
+            randomFrom(nodes_in_zone_a.get(0), nodes_in_zone_b.get(0))
+        ).admin().cluster().prepareGetWeightedRouting().setAwarenessAttribute("zone").setRequestLocal(true).get();
+        assertEquals(weightedRouting, weightedRoutingResponse.weights());
+        assertFalse(weightedRoutingResponse.getDiscoveredClusterManager());
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+    }
+
+    public void testWeightedRoutingMetadataOnOSProcessRestart() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        // put api call to set weights
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        ensureStableCluster(3);
+
+        // routing weights are set in cluster metadata
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        ensureGreen();
+
+        // Restart a random data node and check that OS process comes healthy
+        internalCluster().restartRandomDataNode();
+        ensureGreen();
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+    }
+
+    public void testWeightedRoutingOnOSProcessRestartAfterWeightDelete() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        // put api call to set weights
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        ensureStableCluster(3);
+
+        // routing weights are set in cluster metadata
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        ensureGreen();
+
+        // delete weighted routing metadata
+        ClusterDeleteWeightedRoutingResponse deleteResponse = client().admin().cluster().prepareDeleteWeightedRouting().setVersion(0).get();
+        assertTrue(deleteResponse.isAcknowledged());
+
+        // Restart a random data node and check that OS process comes healthy
+        internalCluster().restartRandomDataNode();
+        ensureGreen();
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+    }
+
+    public void testDeleteWeightedRouting_WeightsNotSet() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        assertNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // delete weighted routing metadata
+        ResourceNotFoundException exception = expectThrows(
+            ResourceNotFoundException.class,
+            () -> client().admin().cluster().prepareDeleteWeightedRouting().setVersion(-1).get()
+        );
+        assertEquals(RestStatus.NOT_FOUND, exception.status());
+    }
+
+    public void testDeleteWeightedRouting_WeightsAreSet() throws IOException {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("3").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        // put api call to set weights
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(response.isAcknowledged());
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // delete weighted routing metadata
+        ClusterDeleteWeightedRoutingResponse deleteResponse = client().admin().cluster().prepareDeleteWeightedRouting().setVersion(0).get();
+        assertTrue(deleteResponse.isAcknowledged());
+    }
+
+    public void testPutAndDeleteWithVersioning() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> starting 6 nodes on different zones");
+        int nodeCountPerAZ = 2;
+
+        logger.info("--> starting a dedicated cluster manager node");
+        internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 1 nodes on zones 'a' & 'b' & 'c'");
+        internalCluster().startDataOnlyNodes(nodeCountPerAZ, Settings.builder().put(commonSettings).put("node.attr.zone", "a").build());
+        internalCluster().startDataOnlyNodes(nodeCountPerAZ, Settings.builder().put(commonSettings).put("node.attr.zone", "b").build());
+        internalCluster().startDataOnlyNodes(nodeCountPerAZ, Settings.builder().put(commonSettings).put("node.attr.zone", "c").build());
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("7").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 2.0, "c", 3.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(response.isAcknowledged());
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // update weights api call with correct version number
+        weights = Map.of("a", 1.0, "b", 2.0, "c", 4.0);
+        weightedRouting = new WeightedRouting("zone", weights);
+        response = client().admin().cluster().prepareWeightedRouting().setWeightedRouting(weightedRouting).setVersion(0).get();
+        assertTrue(response.isAcknowledged());
+
+        // update weights api call with incorrect version number
+        weights = Map.of("a", 1.0, "b", 2.0, "c", 4.0);
+        WeightedRouting weightedRouting1 = new WeightedRouting("zone", weights);
+        UnsupportedWeightedRoutingStateException exception = expectThrows(
+            UnsupportedWeightedRoutingStateException.class,
+            () -> client().admin().cluster().prepareWeightedRouting().setWeightedRouting(weightedRouting1).setVersion(100).get()
+        );
+        assertEquals(exception.status(), RestStatus.CONFLICT);
+
+        // get weights call
+        ClusterGetWeightedRoutingResponse weightedRoutingResponse = client().admin()
+            .cluster()
+            .prepareGetWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .get();
+
+        // update weights call using version returned by get api call
+        weights = Map.of("a", 1.0, "b", 2.0, "c", 5.0);
+        weightedRouting = new WeightedRouting("zone", weights);
+        response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(weightedRoutingResponse.getVersion())
+            .get();
+        assertTrue(response.isAcknowledged());
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // delete weights by awareness attribute
+        ClusterDeleteWeightedRoutingResponse deleteResponse = client().admin()
+            .cluster()
+            .prepareDeleteWeightedRouting()
+            .setAwarenessAttribute("zone")
+            .setVersion(2)
+            .get();
+        assertTrue(deleteResponse.isAcknowledged());
+
+        // update weights again and make sure that version number got updated on delete
+        weights = Map.of("a", 1.0, "b", 2.0, "c", 6.0);
+        weightedRouting = new WeightedRouting("zone", weights);
+        response = client().admin().cluster().prepareWeightedRouting().setWeightedRouting(weightedRouting).setVersion(3).get();
+        assertTrue(response.isAcknowledged());
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // delete weights
+        deleteResponse = client().admin().cluster().prepareDeleteWeightedRouting().setVersion(4).get();
+        assertTrue(deleteResponse.isAcknowledged());
+
+        // delete weights call, incorrect version number
+        UnsupportedWeightedRoutingStateException deleteException = expectThrows(
+            UnsupportedWeightedRoutingStateException.class,
+            () -> client().admin().cluster().prepareDeleteWeightedRouting().setVersion(7).get()
+        );
+        assertEquals(RestStatus.CONFLICT, deleteException.status());
+    }
+
+    public void testClusterHealthResponseWithEnsureNodeWeighedInParam() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        logger.info("--> starting 3 nodes on different zones");
+        int nodeCountPerAZ = 1;
+
+        logger.info("--> starting a dedicated cluster manager node");
+        String clusterManager = internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 2 nodes on zones 'a' & 'b' & 'c'");
+        List<String> nodes_in_zone_a = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        List<String> nodes_in_zone_b = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        List<String> nodes_in_zone_c = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("4").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertTrue(response.isAcknowledged());
+        assertNotNull(internalCluster().clusterService().state().metadata().weightedRoutingMetadata());
+
+        // Check cluster health for weighed in node, health check should return a response with 200 status code
+        ClusterHealthResponse nodeLocalHealth = client(nodes_in_zone_a.get(0)).admin()
+            .cluster()
+            .prepareHealth()
+            .setLocal(true)
+            .setEnsureNodeWeighedIn(true)
+            .get();
+        assertFalse(nodeLocalHealth.isTimedOut());
+
+        // Check cluster health for weighed away node, health check should respond with an exception
+        NodeWeighedAwayException ex = expectThrows(
+            NodeWeighedAwayException.class,
+            () -> client(nodes_in_zone_c.get(0)).admin().cluster().prepareHealth().setLocal(true).setEnsureNodeWeighedIn(true).get()
+        );
+        assertTrue(ex.getMessage().contains("local node is weighed away"));
+
+        logger.info("--> running cluster health on an index that does not exists");
+        ClusterHealthResponse healthResponse = client(nodes_in_zone_c.get(0)).admin()
+            .cluster()
+            .prepareHealth("test1")
+            .setLocal(true)
+            .setEnsureNodeWeighedIn(true)
+            .setTimeout("1s")
+            .execute()
+            .actionGet();
+        assertThat(healthResponse.isTimedOut(), equalTo(true));
+        assertThat(healthResponse.getStatus(), equalTo(ClusterHealthStatus.RED));
+        assertThat(healthResponse.getIndices().isEmpty(), equalTo(true));
+
+        Set<String> nodesInOneSide = Stream.of(nodes_in_zone_a.get(0), nodes_in_zone_b.get(0), nodes_in_zone_c.get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(clusterManager).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        // wait for leader checker to fail
+        Thread.sleep(13000);
+
+        // Check cluster health for weighed in node when cluster manager is not discovered, health check should
+        // return a response with 503 status code
+        assertThrows(
+            ClusterManagerNotDiscoveredException.class,
+            () -> client(nodes_in_zone_a.get(0)).admin().cluster().prepareHealth().setLocal(true).setEnsureNodeWeighedIn(true).get()
+        );
+
+        // Check cluster health for weighed away node when cluster manager is not discovered, health check should
+        // return a response with 503 status code
+        assertThrows(
+            ClusterManagerNotDiscoveredException.class,
+            () -> client(nodes_in_zone_c.get(0)).admin().cluster().prepareHealth().setLocal(true).setEnsureNodeWeighedIn(true).get()
+        );
+        networkDisruption.stopDisrupting();
+        Thread.sleep(1000);
+
+        // delete weights
+        ClusterDeleteWeightedRoutingResponse deleteResponse = client().admin().cluster().prepareDeleteWeightedRouting().setVersion(0).get();
+        assertTrue(deleteResponse.isAcknowledged());
+
+        // Check local cluster health
+        nodeLocalHealth = client(nodes_in_zone_c.get(0)).admin()
+            .cluster()
+            .prepareHealth()
+            .setLocal(true)
+            .setEnsureNodeWeighedIn(true)
+            .get();
+        assertFalse(nodeLocalHealth.isTimedOut());
+        assertTrue(nodeLocalHealth.hasDiscoveredClusterManager());
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
index eb3e61d83a948..100674a44737e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
@@ -36,14 +36,17 @@
 import org.apache.lucene.tests.mockfile.FilterFileSystemProvider;
 import org.apache.lucene.tests.mockfile.FilterPath;
 import org.apache.lucene.util.Constants;
-
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
+import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.cluster.ClusterInfoService;
+import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.InternalClusterInfoService;
+import org.opensearch.cluster.MockInternalClusterInfoService;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
@@ -54,20 +57,21 @@
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.monitor.fs.FsService;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.snapshots.RestoreInfo;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotState;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
 import org.junit.After;
 import org.junit.Before;
@@ -83,8 +87,8 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
@@ -92,6 +96,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
+import static org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider.INDEX_ROUTING_ALLOCATION_ENABLE_SETTING;
 import static org.opensearch.common.util.concurrent.ConcurrentCollections.newConcurrentMap;
 import static org.opensearch.index.store.Store.INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -127,6 +132,8 @@ public void removeFilesystemProvider() {
     }
 
     private static final long WATERMARK_BYTES = new ByteSizeValue(10, ByteSizeUnit.KB).getBytes();
+    private static final long TOTAL_SPACE_BYTES = new ByteSizeValue(100, ByteSizeUnit.KB).getBytes();
+    private static final String INDEX_ROUTING_ALLOCATION_NODE_SETTING = "index.routing.allocation.include._name";
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
@@ -150,36 +157,28 @@ protected Settings nodeSettings(int nodeOrdinal) {
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Collections.singletonList(InternalSettingsPlugin.class);
+        return List.of(InternalSettingsPlugin.class, MockInternalClusterInfoService.TestPlugin.class);
     }
 
     public void testHighWatermarkNotExceeded() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String dataNodeName = internalCluster().startDataOnlyNode();
         ensureStableCluster(3);
 
-        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster().getCurrentMasterNodeInstance(
-            ClusterInfoService.class
-        );
-        internalCluster().getCurrentMasterNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
 
         final String dataNode0Id = internalCluster().getInstance(NodeEnvironment.class, dataNodeName).nodeId();
         final Path dataNode0Path = internalCluster().getInstance(Environment.class, dataNodeName).dataFiles()[0];
 
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
-        createIndex(
-            indexName,
-            Settings.builder()
-                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6)
-                .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
-                .build()
-        );
-        final long minShardSize = createReasonableSizedShards(indexName);
+        final long minShardSize = createAndPopulateIndex(indexName, null);
 
-        // reduce disk size of node 0 so that no shards fit below the high watermark, forcing all shards onto the other data node
-        // (subtract the translog size since the disk threshold decider ignores this and may therefore move the shard back again)
+        // reduce disk size of node 0 so that no shards fit below the high watermark, forcing all shards onto the other
+        // data node (subtract the translog size since the disk threshold decider ignores this and may therefore move
+        // the shard back again).
         fileSystemProvider.getTestFileStore(dataNode0Path).setTotalSpace(minShardSize + WATERMARK_BYTES - 1L);
         assertBusyWithDiskUsageRefresh(dataNode0Id, indexName, empty());
 
@@ -188,8 +187,178 @@ public void testHighWatermarkNotExceeded() throws Exception {
         assertBusyWithDiskUsageRefresh(dataNode0Id, indexName, hasSize(1));
     }
 
+    public void testIndexCreateBlockWhenAllNodesExceededHighWatermark() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Reduce disk space of all node until all of them is breaching high disk watermark.
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, WATERMARK_BYTES - 1)
+        );
+        assertBusy(() -> {
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertFalse(state1.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    public void testIndexCreateBlockNotAppliedWhenAnyNodesBelowHighWatermark() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNodes(2);
+        ensureStableCluster(3);
+
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+
+        // Validate cluster block is not applied on the cluster
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+        assertFalse(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+    }
+
+    public void testIndexCreateBlockIsRemovedWhenAnyNodesNotExceedHighWatermarkWithAutoReleaseEnabled() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Reduce disk space of all node until all of them is breaching high disk watermark.
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, WATERMARK_BYTES - 1)
+        );
+
+        // Validate if cluster block is applied on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+
+        // Free all the space
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, TOTAL_SPACE_BYTES)
+        );
+
+        // Validate if index create block is removed on the cluster
+        assertBusy(() -> {
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertFalse(state1.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    public void testIndexCreateBlockIsRemovedWhenAnyNodesNotExceedHighWatermarkWithAutoReleaseDisabled() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .put(DiskThresholdSettings.CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Reduce disk space of all node until all of them is breaching high disk watermark
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, WATERMARK_BYTES - 1)
+        );
+
+        // Validate if cluster block is applied on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+
+        // Free all the space
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, TOTAL_SPACE_BYTES)
+        );
+
+        // Validate index create block is not removed on the cluster
+        assertBusy(() -> {
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state1.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    public void testDiskMonitorAppliesBlockBackWhenUserRemovesIndexCreateBlock() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .put(DiskThresholdSettings.CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+
+        // User applies index create block.
+        Settings createBlockSetting = Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), "true").build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(createBlockSetting).get());
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Reduce disk space of all node until all of them is breaching high disk watermark and DiskMonitor applies block.
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, WATERMARK_BYTES - 1)
+        );
+
+        // Validate if cluster block is applied on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+
+        // User removes the block.
+        Settings removeBlockSetting = Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), false).build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(removeBlockSetting).get());
+
+        // Refresh so that DiskThresholdMonitor kicks in and applies block.
+        getMockInternalClusterInfoService().refresh();
+        // Validate index create block is not removed on the cluster
+        assertBusy(() -> {
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state1.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    public void testIndexCreateBlockWithAReadOnlyBlock() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        final List<String> dataNodeNames = internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Create one of the index.
+        final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
+        createAndPopulateIndex(indexName, dataNodeNames.get(0));
+        // Apply a read_only_allow_delete_block on one of the index
+        // (can happen if the corresponding node has breached flood stage watermark).
+        final Settings readOnlySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_READ_ONLY_ALLOW_DELETE, Boolean.TRUE.toString())
+            .build();
+        client().admin().indices().prepareUpdateSettings(indexName).setSettings(readOnlySettings).get();
+
+        // Reduce disk space of all node until all of them is breaching high disk watermark.
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, WATERMARK_BYTES - 1)
+        );
+
+        // Validate index create block is applied on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
     public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String dataNodeName = internalCluster().startDataOnlyNode();
         ensureStableCluster(3);
@@ -202,24 +371,15 @@ public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Excepti
                 .setSettings(Settings.builder().put("location", randomRepoPath()).put("compress", randomBoolean()))
         );
 
-        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster().getCurrentMasterNodeInstance(
-            ClusterInfoService.class
-        );
-        internalCluster().getCurrentMasterNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
 
         final String dataNode0Id = internalCluster().getInstance(NodeEnvironment.class, dataNodeName).nodeId();
         final Path dataNode0Path = internalCluster().getInstance(Environment.class, dataNodeName).dataFiles()[0];
 
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
-        createIndex(
-            indexName,
-            Settings.builder()
-                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6)
-                .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
-                .build()
-        );
-        final long minShardSize = createReasonableSizedShards(indexName);
+        final long minShardSize = createAndPopulateIndex(indexName, null);
 
         final CreateSnapshotResponse createSnapshotResponse = client().admin()
             .cluster()
@@ -274,6 +434,79 @@ public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Excepti
         assertBusyWithDiskUsageRefresh(dataNode0Id, indexName, hasSize(1));
     }
 
+    public void testDiskMonitorResetLastRuntimeMilliSecOnlyInFirstCall() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE.getKey(), false)
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), false)
+            .build();
+
+        internalCluster().startClusterManagerOnlyNode(settings);
+        internalCluster().startDataOnlyNodes(2, settings);
+        ensureStableCluster(3);
+
+        final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
+        // Reduce disk space of all node.
+        clusterInfoService.setDiskUsageFunctionAndRefresh((discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, 0));
+
+        // Validate if cluster block is applied on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+
+        // User removes index create block.
+        Settings removeBlockSetting = Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), "false").build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(removeBlockSetting).get());
+        // Free all the space
+        clusterInfoService.setDiskUsageFunctionAndRefresh(
+            (discoveryNode, fsInfoPath) -> setDiskUsage(fsInfoPath, TOTAL_SPACE_BYTES, TOTAL_SPACE_BYTES)
+        );
+
+        // Validate index create block is removed on the cluster
+        assertBusy(() -> {
+            ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertFalse(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    private String populateNode(final String dataNodeName) throws Exception {
+        final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
+        createAndPopulateIndex(indexName, dataNodeName);
+        return indexName;
+    }
+
+    private long createAndPopulateIndex(final String indexName, final String nodeName) throws Exception {
+
+        final Settings.Builder indexSettingBuilder = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED.getKey(), false);
+
+        // Depending on node name specified or not, we determine whether to enable node name based shard routing for index
+        // and whether reallocation is disabled on that index or not.
+        if (nodeName != null) {
+            indexSettingBuilder.put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(INDEX_ROUTING_ALLOCATION_NODE_SETTING, nodeName);
+            createIndex(indexName, indexSettingBuilder.build());
+            assertAcked(
+                client().admin()
+                    .indices()
+                    .updateSettings(
+                        new UpdateSettingsRequest(indexName).settings(
+                            Settings.builder().put(INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.getKey(), "none")
+                        )
+                    )
+                    .get()
+            );
+
+            ensureGreen(indexName);
+        } else {
+            indexSettingBuilder.put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6);
+            createIndex(indexName, indexSettingBuilder.build());
+        }
+
+        return createReasonableSizedShards(indexName);
+    }
+
     private Set<ShardRouting> getShardRoutings(final String nodeId, final String indexName) {
         final Set<ShardRouting> shardRoutings = new HashSet<>();
         for (IndexShardRoutingTable indexShardRoutingTable : client().admin()
@@ -296,7 +529,7 @@ private Set<ShardRouting> getShardRoutings(final String nodeId, final String ind
     }
 
     /**
-     * Index documents until all the shards are at least WATERMARK_BYTES in size, and return the size of the smallest shard
+     * Index documents until all the shards are at least WATERMARK_BYTES in size, and return the size of the smallest shard.
      */
     private long createReasonableSizedShards(final String indexName) throws InterruptedException {
         while (true) {
@@ -328,13 +561,17 @@ private long createReasonableSizedShards(final String indexName) throws Interrup
         }
     }
 
+    private static FsInfo.Path setDiskUsage(FsInfo.Path original, long totalBytes, long freeBytes) {
+        return new FsInfo.Path(original.getPath(), original.getMount(), totalBytes, freeBytes, freeBytes);
+    }
+
     private void refreshDiskUsage() {
-        final ClusterInfoService clusterInfoService = internalCluster().getCurrentMasterNodeInstance(ClusterInfoService.class);
+        final ClusterInfoService clusterInfoService = internalCluster().getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
         ((InternalClusterInfoService) clusterInfoService).refresh();
         // if the nodes were all under the low watermark already (but unbalanced) then a change in the disk usage doesn't trigger a reroute
         // even though it's now possible to achieve better balance, so we have to do an explicit reroute. TODO fix this?
         if (StreamSupport.stream(clusterInfoService.getClusterInfo().getNodeMostAvailableDiskUsages().values().spliterator(), false)
-            .allMatch(cur -> cur.value.getFreeBytes() > WATERMARK_BYTES)) {
+            .allMatch(cur -> cur.getFreeBytes() > WATERMARK_BYTES)) {
             assertAcked(client().admin().cluster().prepareReroute());
         }
 
@@ -353,7 +590,7 @@ private void refreshDiskUsage() {
     private void assertBusyWithDiskUsageRefresh(String nodeName, String indexName, Matcher<? super Set<ShardRouting>> matcher)
         throws Exception {
         assertBusy(() -> {
-            // refresh the master's ClusterInfoService before checking the assigned shards because DiskThresholdMonitor might still
+            // refresh the cluster-manager's ClusterInfoService before checking the assigned shards because DiskThresholdMonitor might still
             // be processing a previous ClusterInfo update and will skip the new one (see DiskThresholdMonitor#onNewInfo(ClusterInfo)
             // and its internal checkInProgress flag)
             refreshDiskUsage();
@@ -363,6 +600,10 @@ private void assertBusyWithDiskUsageRefresh(String nodeName, String indexName, M
         }, 30L, TimeUnit.SECONDS);
     }
 
+    private MockInternalClusterInfoService getMockInternalClusterInfoService() {
+        return (MockInternalClusterInfoService) internalCluster().getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+    }
+
     private static class TestFileStore extends FilterFileStore {
 
         private final Path path;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/MockDiskUsagesIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/MockDiskUsagesIT.java
index 05b0f10be02f3..a7755841c9ea9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/MockDiskUsagesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/MockDiskUsagesIT.java
@@ -269,9 +269,9 @@ public void testOnlyMovesEnoughShardsToDropBelowHighWatermark() throws Exception
 
         final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
 
-        final AtomicReference<ClusterState> masterAppliedClusterState = new AtomicReference<>();
-        internalCluster().getCurrentMasterNodeInstance(ClusterService.class).addListener(event -> {
-            masterAppliedClusterState.set(event.state());
+        final AtomicReference<ClusterState> clusterManagerAppliedClusterState = new AtomicReference<>();
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> {
+            clusterManagerAppliedClusterState.set(event.state());
             clusterInfoService.refresh(); // so that a subsequent reroute sees disk usage according to the current state
         });
 
@@ -326,7 +326,7 @@ public void testOnlyMovesEnoughShardsToDropBelowHighWatermark() throws Exception
                 fsInfoPath,
                 1000L,
                 discoveryNode.getId().equals(nodeIds.get(2))
-                    ? 101L - masterAppliedClusterState.get().getRoutingNodes().node(nodeIds.get(2)).numberOfOwningShards()
+                    ? 101L - clusterManagerAppliedClusterState.get().getRoutingNodes().node(nodeIds.get(2)).numberOfOwningShards()
                     : 1000L
             )
         );
@@ -349,7 +349,7 @@ public void testDoesNotExceedLowWatermarkWhenRebalancing() throws Exception {
             internalCluster().startNode(Settings.builder().put(Environment.PATH_DATA_SETTING.getKey(), createTempDir()));
         }
 
-        final AtomicReference<ClusterState> masterAppliedClusterState = new AtomicReference<>();
+        final AtomicReference<ClusterState> clusterManagerAppliedClusterState = new AtomicReference<>();
 
         final MockInternalClusterInfoService clusterInfoService = getMockInternalClusterInfoService();
 
@@ -358,9 +358,9 @@ public void testDoesNotExceedLowWatermarkWhenRebalancing() throws Exception {
             false
         ).map(RoutingNode::nodeId).collect(Collectors.toList());
 
-        internalCluster().getCurrentMasterNodeInstance(ClusterService.class).addListener(event -> {
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> {
             assertThat(event.state().getRoutingNodes().node(nodeIds.get(2)).size(), lessThanOrEqualTo(1));
-            masterAppliedClusterState.set(event.state());
+            clusterManagerAppliedClusterState.set(event.state());
             clusterInfoService.refresh(); // so that a subsequent reroute sees disk usage according to the current state
         });
 
@@ -385,7 +385,7 @@ public void testDoesNotExceedLowWatermarkWhenRebalancing() throws Exception {
                 fsInfoPath,
                 1000L,
                 discoveryNode.getId().equals(nodeIds.get(2))
-                    ? 150L - masterAppliedClusterState.get().getRoutingNodes().node(nodeIds.get(2)).numberOfOwningShards()
+                    ? 150L - clusterManagerAppliedClusterState.get().getRoutingNodes().node(nodeIds.get(2)).numberOfOwningShards()
                     : 1000L
             )
         );
@@ -544,7 +544,7 @@ private Map<String, Integer> getShardCountByNodeId() {
     }
 
     private MockInternalClusterInfoService getMockInternalClusterInfoService() {
-        return (MockInternalClusterInfoService) internalCluster().getCurrentMasterNodeInstance(ClusterInfoService.class);
+        return (MockInternalClusterInfoService) internalCluster().getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
     }
 
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/service/ClusterServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/service/ClusterServiceIT.java
index 252053f4968b4..7d9ffb23a2cf7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/service/ClusterServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/service/ClusterServiceIT.java
@@ -391,7 +391,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
 
         // The tasks can be re-ordered, so we need to check out-of-order
         Set<String> controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10"));
-        List<PendingClusterTask> pendingClusterTasks = clusterService.getMasterService().pendingTasks();
+        List<PendingClusterTask> pendingClusterTasks = clusterService.getClusterManagerService().pendingTasks();
         assertThat(pendingClusterTasks.size(), greaterThanOrEqualTo(10));
         assertThat(pendingClusterTasks.get(0).getSource().string(), equalTo("1"));
         assertThat(pendingClusterTasks.get(0).isExecuting(), equalTo(true));
@@ -413,7 +413,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         invoked2.await();
 
         // whenever we test for no tasks, we need to wait since this is a live node
-        assertBusy(() -> assertTrue("Pending tasks not empty", clusterService.getMasterService().pendingTasks().isEmpty()));
+        assertBusy(() -> assertTrue("Pending tasks not empty", clusterService.getClusterManagerService().pendingTasks().isEmpty()));
         waitNoPendingTasksOnAll();
 
         final CountDownLatch block2 = new CountDownLatch(1);
@@ -453,7 +453,7 @@ public void onFailure(String source, Exception e) {
         }
         Thread.sleep(100);
 
-        pendingClusterTasks = clusterService.getMasterService().pendingTasks();
+        pendingClusterTasks = clusterService.getClusterManagerService().pendingTasks();
         assertThat(pendingClusterTasks.size(), greaterThanOrEqualTo(5));
         controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5"));
         for (PendingClusterTask task : pendingClusterTasks) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/settings/ClusterSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/settings/ClusterSettingsIT.java
index 14365bba1e016..708be8b33fda8 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/settings/ClusterSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/settings/ClusterSettingsIT.java
@@ -41,11 +41,10 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
 import org.junit.After;
 
 import java.util.Arrays;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/settings/SettingsFilteringIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/settings/SettingsFilteringIT.java
index 6de13ebe457a2..b6fbb21087b4d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/settings/SettingsFilteringIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/settings/SettingsFilteringIT.java
@@ -47,10 +47,8 @@
 import java.util.List;
 
 import static org.opensearch.action.admin.cluster.node.info.NodesInfoRequest.Metric.SETTINGS;
-
 import static org.opensearch.test.OpenSearchIntegTestCase.Scope.SUITE;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/shards/ClusterShardLimitIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/shards/ClusterShardLimitIT.java
index a92849a077376..fb97ae59aae91 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/shards/ClusterShardLimitIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/shards/ClusterShardLimitIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.cluster.shards;
 
 import org.opensearch.Version;
-
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
@@ -41,20 +40,36 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Priority;
+import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.indices.ShardLimitValidator;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotState;
+import org.opensearch.snapshots.mockstore.MockRepository;
+import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.MockHttpTransport;
+import org.opensearch.test.NodeConfigurationSource;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.nio.MockNioTransportPlugin;
 
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.Function;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_NODE;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_MAX_SHARDS_PER_CLUSTER_KEY;
 import static org.opensearch.test.NodeRoles.dataNode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
@@ -62,11 +77,17 @@
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
 public class ClusterShardLimitIT extends OpenSearchIntegTestCase {
-    private static final String shardsPerNodeKey = ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey();
+    private static final String shardsPerNodeKey = SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey();
+    private static final String ignoreDotIndexKey = ShardLimitValidator.SETTING_CLUSTER_IGNORE_DOT_INDEXES.getKey();
 
     public void testSettingClusterMaxShards() {
         int shardsPerNode = between(1, 500_000);
-        setShardsPerNode(shardsPerNode);
+        setMaxShardLimit(shardsPerNode, shardsPerNodeKey);
+    }
+
+    public void testSettingIgnoreDotIndexes() {
+        boolean ignoreDotIndexes = randomBoolean();
+        setIgnoreDotIndex(ignoreDotIndexes);
     }
 
     public void testMinimumPerNode() {
@@ -99,8 +120,7 @@ public void testIndexCreationOverLimit() {
 
         ShardCounts counts = ShardCounts.forDataNodeCount(dataNodes);
 
-        setShardsPerNode(counts.getShardsPerNode());
-
+        setMaxShardLimit(counts.getShardsPerNode(), shardsPerNodeKey);
         // Create an index that will bring us up to the limit
         createIndex(
             "test",
@@ -127,12 +147,186 @@ public void testIndexCreationOverLimit() {
         assertFalse(clusterState.getMetadata().hasIndex("should-fail"));
     }
 
+    /**
+     * The test checks if the index starting with the dot can be created if the node has
+     * number of shards equivalent to the cluster.max_shards_per_node and the cluster.ignore_Dot_indexes
+     * setting is set to true. If the cluster.ignore_Dot_indexes is set to true index creation of
+     * indexes starting with dot would succeed.
+     */
+    public void testIndexCreationOverLimitForDotIndexesSucceeds() {
+        int dataNodes = client().admin().cluster().prepareState().get().getState().getNodes().getDataNodes().size();
+
+        // Setting the cluster.max_shards_per_node setting according to the data node count.
+        setMaxShardLimit(dataNodes, shardsPerNodeKey);
+        setIgnoreDotIndex(true);
+
+        /*
+            Create an index that will bring us up to the limit. It would create index with primary equal to the
+            dataNodes * dataNodes so that cluster.max_shards_per_node setting is reached.
+         */
+        createIndex(
+            "test",
+            Settings.builder()
+                .put(indexSettings())
+                .put(SETTING_NUMBER_OF_SHARDS, dataNodes * dataNodes)
+                .put(SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+
+        // Getting total active shards in the cluster.
+        int currentActiveShards = client().admin().cluster().prepareHealth().get().getActiveShards();
+
+        // Getting cluster.max_shards_per_node setting
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        String maxShardsPerNode = clusterState.getMetadata().settings().get(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey());
+
+        // Checking if the total shards created are equivalent to dataNodes * cluster.max_shards_per_node
+        assertEquals(dataNodes * Integer.parseInt(maxShardsPerNode), currentActiveShards);
+
+        createIndex(
+            ".test-index",
+            Settings.builder().put(indexSettings()).put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0).build()
+        );
+
+        clusterState = client().admin().cluster().prepareState().get().getState();
+        assertTrue(clusterState.getMetadata().hasIndex(".test-index"));
+    }
+
+    /**
+     * The test checks if the index starting with the dot should not be created if the node has
+     * number of shards equivalent to the cluster.max_shards_per_node and the cluster.ignore_Dot_indexes
+     * setting is set to false. If the cluster.ignore_Dot_indexes is set to false index creation of
+     * indexes starting with dot would fail as well.
+     */
+    public void testIndexCreationOverLimitForDotIndexesFail() {
+        int dataNodes = client().admin().cluster().prepareState().get().getState().getNodes().getDataNodes().size();
+        int maxAllowedShards = dataNodes * dataNodes;
+
+        // Setting the cluster.max_shards_per_node setting according to the data node count.
+        setMaxShardLimit(dataNodes, shardsPerNodeKey);
+
+        /*
+            Create an index that will bring us up to the limit. It would create index with primary equal to the
+            dataNodes * dataNodes so that cluster.max_shards_per_node setting is reached.
+         */
+        createIndex(
+            "test",
+            Settings.builder()
+                .put(indexSettings())
+                .put(SETTING_NUMBER_OF_SHARDS, maxAllowedShards)
+                .put(SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+
+        // Getting total active shards in the cluster.
+        int currentActiveShards = client().admin().cluster().prepareHealth().get().getActiveShards();
+
+        // Getting cluster.max_shards_per_node setting
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        String maxShardsPerNode = clusterState.getMetadata().settings().get(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey());
+
+        // Checking if the total shards created are equivalent to dataNodes * cluster.max_shards_per_node
+        assertEquals(dataNodes * Integer.parseInt(maxShardsPerNode), currentActiveShards);
+
+        int extraShardCount = 1;
+        try {
+            createIndex(
+                ".test-index",
+                Settings.builder()
+                    .put(indexSettings())
+                    .put(SETTING_NUMBER_OF_SHARDS, extraShardCount)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 0)
+                    .build()
+            );
+        } catch (IllegalArgumentException e) {
+            verifyException(maxAllowedShards, currentActiveShards, extraShardCount, e);
+        }
+        clusterState = client().admin().cluster().prepareState().get().getState();
+        assertFalse(clusterState.getMetadata().hasIndex(".test-index"));
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/6287")
+    public void testCreateIndexWithMaxClusterShardSetting() {
+        int dataNodes = client().admin().cluster().prepareState().get().getState().getNodes().getDataNodes().size();
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        setMaxShardLimit(dataNodes, shardsPerNodeKey);
+
+        int maxAllowedShards = dataNodes + 1;
+        int extraShardCount = maxAllowedShards + 1;
+        // Getting total active shards in the cluster.
+        int currentActiveShards = client().admin().cluster().prepareHealth().get().getActiveShards();
+        try {
+            setMaxShardLimit(maxAllowedShards, SETTING_MAX_SHARDS_PER_CLUSTER_KEY);
+            prepareCreate("test_index_with_cluster_shard_limit").setSettings(
+                Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, extraShardCount).put(SETTING_NUMBER_OF_REPLICAS, 0).build()
+            ).get();
+        } catch (final IllegalArgumentException ex) {
+            verifyException(Math.min(maxAllowedShards, dataNodes * dataNodes), currentActiveShards, extraShardCount, ex);
+        } finally {
+            setMaxShardLimit(-1, SETTING_MAX_SHARDS_PER_CLUSTER_KEY);
+        }
+    }
+
+    /**
+     * The test checks if the index starting with the .ds- can be created if the node has
+     * number of shards equivalent to the cluster.max_shards_per_node and the cluster.ignore_Dot_indexes
+     * setting is set to true. If the cluster.ignore_Dot_indexes is set to true index creation of
+     * indexes starting with dot would only succeed and dataStream indexes would still have validation applied.
+     */
+    public void testIndexCreationOverLimitForDataStreamIndexes() {
+        int dataNodes = client().admin().cluster().prepareState().get().getState().getNodes().getDataNodes().size();
+        int maxAllowedShards = dataNodes * dataNodes;
+
+        // Setting the cluster.max_shards_per_node setting according to the data node count.
+        setMaxShardLimit(dataNodes, shardsPerNodeKey);
+        setIgnoreDotIndex(true);
+
+        /*
+            Create an index that will bring us up to the limit. It would create index with primary equal to the
+            dataNodes * dataNodes so that cluster.max_shards_per_node setting is reached.
+         */
+        createIndex(
+            "test",
+            Settings.builder()
+                .put(indexSettings())
+                .put(SETTING_NUMBER_OF_SHARDS, maxAllowedShards)
+                .put(SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+
+        // Getting total active shards in the cluster.
+        int currentActiveShards = client().admin().cluster().prepareHealth().get().getActiveShards();
+
+        // Getting cluster.max_shards_per_node setting
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        String maxShardsPerNode = clusterState.getMetadata().settings().get(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey());
+
+        // Checking if the total shards created are equivalent to dataNodes * cluster.max_shards_per_node
+        assertEquals(dataNodes * Integer.parseInt(maxShardsPerNode), currentActiveShards);
+
+        int extraShardCount = 1;
+        try {
+            createIndex(
+                ".ds-test-index",
+                Settings.builder()
+                    .put(indexSettings())
+                    .put(SETTING_NUMBER_OF_SHARDS, extraShardCount)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 0)
+                    .build()
+            );
+        } catch (IllegalArgumentException e) {
+            verifyException(maxAllowedShards, currentActiveShards, extraShardCount, e);
+        }
+        clusterState = client().admin().cluster().prepareState().get().getState();
+        assertFalse(clusterState.getMetadata().hasIndex(".ds-test-index"));
+    }
+
     public void testIndexCreationOverLimitFromTemplate() {
         int dataNodes = client().admin().cluster().prepareState().get().getState().getNodes().getDataNodes().size();
 
         final ShardCounts counts = ShardCounts.forDataNodeCount(dataNodes);
 
-        setShardsPerNode(counts.getShardsPerNode());
+        setMaxShardLimit(counts.getShardsPerNode(), shardsPerNodeKey);
 
         if (counts.getFirstIndexShards() > 0) {
             createIndex(
@@ -175,7 +369,7 @@ public void testIncreaseReplicasOverLimit() {
 
         int firstShardCount = between(2, 10);
         int shardsPerNode = firstShardCount - 1;
-        setShardsPerNode(shardsPerNode);
+        setMaxShardLimit(shardsPerNode, shardsPerNodeKey);
 
         prepareCreate(
             "growing-should-fail",
@@ -221,7 +415,7 @@ public void testChangingMultipleIndicesOverLimit() {
         int secondIndexReplicas = dataNodes;
 
         int shardsPerNode = firstIndexFactor + (secondIndexFactor * (1 + secondIndexReplicas));
-        setShardsPerNode(shardsPerNode);
+        setMaxShardLimit(shardsPerNode, shardsPerNodeKey);
 
         createIndex(
             "test-1-index",
@@ -272,7 +466,7 @@ public void testPreserveExistingSkipsCheck() {
 
         int firstShardCount = between(2, 10);
         int shardsPerNode = firstShardCount - 1;
-        setShardsPerNode(shardsPerNode);
+        setMaxShardLimit(shardsPerNode, shardsPerNodeKey);
 
         prepareCreate(
             "test-index",
@@ -345,7 +539,7 @@ public void testRestoreSnapshotOverLimit() {
         cluster().wipeIndices("snapshot-index");
 
         // Reduce the shard limit and fill it up
-        setShardsPerNode(counts.getShardsPerNode());
+        setMaxShardLimit(counts.getShardsPerNode(), shardsPerNodeKey);
         createIndex(
             "test-fill",
             Settings.builder()
@@ -394,7 +588,7 @@ public void testOpenIndexOverLimit() {
         assertTrue(closeIndexResponse.isAcknowledged());
 
         // Fill up the cluster
-        setShardsPerNode(counts.getShardsPerNode());
+        setMaxShardLimit(counts.getShardsPerNode(), shardsPerNodeKey);
         createIndex(
             "test-fill",
             Settings.builder()
@@ -414,6 +608,100 @@ public void testOpenIndexOverLimit() {
         assertFalse(clusterState.getMetadata().hasIndex("snapshot-index"));
     }
 
+    public void testIgnoreDotSettingOnMultipleNodes() throws IOException, InterruptedException {
+        int maxAllowedShardsPerNode = 10, indexPrimaryShards = 11, indexReplicaShards = 1;
+
+        InternalTestCluster cluster = new InternalTestCluster(
+            randomLong(),
+            createTempDir(),
+            true,
+            true,
+            0,
+            0,
+            "cluster",
+            new NodeConfigurationSource() {
+                @Override
+                public Settings nodeSettings(int nodeOrdinal) {
+                    return Settings.builder()
+                        .put(ClusterShardLimitIT.this.nodeSettings(nodeOrdinal))
+                        .put(NetworkModule.TRANSPORT_TYPE_KEY, getTestTransportType())
+                        .build();
+                }
+
+                @Override
+                public Path nodeConfigPath(int nodeOrdinal) {
+                    return null;
+                }
+            },
+            0,
+            "cluster-",
+            Arrays.asList(
+                TestSeedPlugin.class,
+                MockHttpTransport.TestPlugin.class,
+                MockTransportService.TestPlugin.class,
+                MockNioTransportPlugin.class,
+                InternalSettingsPlugin.class,
+                MockRepository.Plugin.class
+            ),
+            Function.identity()
+        );
+        cluster.beforeTest(random());
+
+        // Starting 3 ClusterManagerOnlyNode nodes
+        cluster.startClusterManagerOnlyNode(Settings.builder().put("cluster.ignore_dot_indexes", true).build());
+        cluster.startClusterManagerOnlyNode(Settings.builder().put("cluster.ignore_dot_indexes", false).build());
+        cluster.startClusterManagerOnlyNode(Settings.builder().put("cluster.ignore_dot_indexes", false).build());
+
+        // Starting 2 data nodes
+        cluster.startDataOnlyNode(Settings.builder().put("cluster.ignore_dot_indexes", false).build());
+        cluster.startDataOnlyNode(Settings.builder().put("cluster.ignore_dot_indexes", false).build());
+
+        // Setting max shards per node to be 10
+        cluster.client()
+            .admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setPersistentSettings(Settings.builder().put(shardsPerNodeKey, maxAllowedShardsPerNode))
+            .get();
+
+        // Creating an index starting with dot having shards greater thn the desired node limit
+        cluster.client()
+            .admin()
+            .indices()
+            .prepareCreate(".test-index")
+            .setSettings(
+                Settings.builder().put(SETTING_NUMBER_OF_SHARDS, indexPrimaryShards).put(SETTING_NUMBER_OF_REPLICAS, indexReplicaShards)
+            )
+            .get();
+
+        // As active ClusterManagerNode setting takes precedence killing the active one.
+        // This would be the first one where cluster.ignore_dot_indexes is true because the above calls are blocking.
+        cluster.stopCurrentClusterManagerNode();
+
+        // Waiting for all shards to get assigned
+        cluster.client().admin().cluster().prepareHealth().setWaitForGreenStatus().get();
+
+        // Creating an index starting with dot having shards greater thn the desired node limit
+        try {
+            cluster.client()
+                .admin()
+                .indices()
+                .prepareCreate(".test-index1")
+                .setSettings(
+                    Settings.builder().put(SETTING_NUMBER_OF_SHARDS, indexPrimaryShards).put(SETTING_NUMBER_OF_REPLICAS, indexReplicaShards)
+                )
+                .get();
+        } catch (IllegalArgumentException e) {
+            ClusterHealthResponse clusterHealth = cluster.client().admin().cluster().prepareHealth().get();
+            int currentActiveShards = clusterHealth.getActiveShards();
+            int dataNodeCount = clusterHealth.getNumberOfDataNodes();
+            int extraShardCount = indexPrimaryShards * (1 + indexReplicaShards);
+            verifyException(maxAllowedShardsPerNode * dataNodeCount, currentActiveShards, extraShardCount, e);
+        }
+
+        IOUtils.close(cluster);
+    }
+
     private int ensureMultipleDataNodes(int dataNodes) {
         if (dataNodes == 1) {
             internalCluster().startNode(dataNode());
@@ -434,23 +722,53 @@ private int ensureMultipleDataNodes(int dataNodes) {
         return dataNodes;
     }
 
-    private void setShardsPerNode(int shardsPerNode) {
+    /**
+     * Set max shard limit on either per node level or on cluster level.
+     *
+     * @param limit the limit value to set.
+     * @param key node level or cluster level setting key.
+     */
+    private void setMaxShardLimit(int limit, String key) {
+        try {
+            ClusterUpdateSettingsResponse response;
+            if (frequently()) {
+                response = client().admin()
+                    .cluster()
+                    .prepareUpdateSettings()
+                    .setPersistentSettings(Settings.builder().put(key, limit).build())
+                    .get();
+                assertEquals(limit, response.getPersistentSettings().getAsInt(key, -1).intValue());
+            } else {
+                response = client().admin()
+                    .cluster()
+                    .prepareUpdateSettings()
+                    .setTransientSettings(Settings.builder().put(key, limit).build())
+                    .get();
+                assertEquals(limit, response.getTransientSettings().getAsInt(key, -1).intValue());
+            }
+        } catch (IllegalArgumentException ex) {
+            fail(ex.getMessage());
+        }
+
+    }
+
+    private void setIgnoreDotIndex(boolean ignoreDotIndex) {
         try {
             ClusterUpdateSettingsResponse response;
             if (frequently()) {
                 response = client().admin()
                     .cluster()
                     .prepareUpdateSettings()
-                    .setPersistentSettings(Settings.builder().put(shardsPerNodeKey, shardsPerNode).build())
+                    .setPersistentSettings(Settings.builder().put(ignoreDotIndexKey, ignoreDotIndex).build())
                     .get();
-                assertEquals(shardsPerNode, response.getPersistentSettings().getAsInt(shardsPerNodeKey, -1).intValue());
+                assertEquals(ignoreDotIndex, response.getPersistentSettings().getAsBoolean(ignoreDotIndexKey, true));
             } else {
                 response = client().admin()
                     .cluster()
                     .prepareUpdateSettings()
-                    .setTransientSettings(Settings.builder().put(shardsPerNodeKey, shardsPerNode).build())
+                    .setTransientSettings(Settings.builder().put(ignoreDotIndexKey, ignoreDotIndex).build())
                     .get();
-                assertEquals(shardsPerNode, response.getTransientSettings().getAsInt(shardsPerNodeKey, -1).intValue());
+                assertEquals(ignoreDotIndex, response.getTransientSettings().getAsBoolean(ignoreDotIndexKey, true));
             }
         } catch (IllegalArgumentException ex) {
             fail(ex.getMessage());
@@ -471,4 +789,15 @@ private void verifyException(int dataNodes, ShardCounts counts, IllegalArgumentE
         assertEquals(expectedError, e.getMessage());
     }
 
+    private void verifyException(int maxShards, int currentShards, int extraShards, IllegalArgumentException e) {
+        String expectedError = "Validation Failed: 1: this action would add ["
+            + extraShards
+            + "] total shards, but this cluster currently has ["
+            + currentShards
+            + "]/["
+            + maxShards
+            + "] maximum shards open;";
+        assertEquals(expectedError, e.getMessage());
+    }
+
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/clustermanager/ClusterManagerTaskThrottlingIT.java b/server/src/internalClusterTest/java/org/opensearch/clustermanager/ClusterManagerTaskThrottlingIT.java
new file mode 100644
index 0000000000000..3b80ef7820e08
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/clustermanager/ClusterManagerTaskThrottlingIT.java
@@ -0,0 +1,214 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.clustermanager;
+
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
+import org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException;
+import org.opensearch.cluster.service.ClusterManagerThrottlingException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.transport.TransportMessageListener;
+import org.opensearch.transport.TransportService;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, numDataNodes = 0)
+public class ClusterManagerTaskThrottlingIT extends OpenSearchIntegTestCase {
+
+    /*
+     * This integ test will test end-end cluster manager throttling feature for
+     * remote cluster manager.
+     *
+     * It will check the number of request coming to cluster manager node
+     * should be total number of requests + throttled requests from cluster manager.
+     * This will ensure the end-end feature is working as cluster manager is throwing
+     * Throttling exception and data node is performing retries on it.
+     *
+     */
+    public void testThrottlingForRemoteClusterManager() throws Exception {
+        try {
+            internalCluster().beforeTest(random());
+            String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+            String dataNode = internalCluster().startDataOnlyNode();
+            int throttlingLimit = randomIntBetween(1, 5);
+            createIndex("test");
+            setPutMappingThrottlingLimit(throttlingLimit);
+
+            TransportService clusterManagerTransportService = (internalCluster().getInstance(TransportService.class, clusterManagerNode));
+            AtomicInteger requestCountOnClusterManager = new AtomicInteger();
+            AtomicInteger throttledRequest = new AtomicInteger();
+            int totalRequest = randomIntBetween(throttlingLimit, 5 * throttlingLimit);
+            CountDownLatch latch = new CountDownLatch(totalRequest);
+
+            clusterManagerTransportService.addMessageListener(new TransportMessageListener() {
+                @Override
+                public void onRequestReceived(long requestId, String action) {
+                    if (action.contains("mapping")) {
+                        requestCountOnClusterManager.incrementAndGet();
+                    }
+                }
+
+                @Override
+                public void onResponseSent(long requestId, String action, Exception error) {
+                    if (action.contains("mapping")) {
+                        throttledRequest.incrementAndGet();
+                        assertEquals(ClusterManagerThrottlingException.class, error.getClass());
+                    }
+                }
+            });
+
+            ActionListener listener = new ActionListener() {
+                @Override
+                public void onResponse(Object o) {
+                    latch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    latch.countDown();
+                    throw new AssertionError(e);
+                }
+            };
+
+            executePutMappingRequests(totalRequest, dataNode, listener);
+            latch.await();
+
+            assertEquals(totalRequest + throttledRequest.get(), requestCountOnClusterManager.get());
+            assertBusy(
+                () -> { assertEquals(clusterService().getMasterService().numberOfThrottledPendingTasks(), throttledRequest.get()); }
+            );
+        } finally {
+            clusterSettingCleanUp();
+        }
+    }
+
+    /*
+     * This will test the throttling feature for single node.
+     *
+     * Here we will assert the client behaviour that client's request is not
+     * failed, i.e. Throttling exception is not passed to the client.
+     * Data node will internally do the retry and request should pass.
+     *
+     */
+    public void testThrottlingForSingleNode() throws Exception {
+        try {
+            internalCluster().beforeTest(random());
+            String node = internalCluster().startNode();
+            int throttlingLimit = randomIntBetween(1, 5);
+            createIndex("test");
+            setPutMappingThrottlingLimit(throttlingLimit);
+
+            AtomicInteger successfulRequest = new AtomicInteger();
+            int totalRequest = randomIntBetween(throttlingLimit, 3 * throttlingLimit);
+            CountDownLatch latch = new CountDownLatch(totalRequest);
+
+            ActionListener listener = new ActionListener() {
+                @Override
+                public void onResponse(Object o) {
+                    successfulRequest.incrementAndGet();
+                    latch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    latch.countDown();
+                    throw new AssertionError(e);
+                }
+            };
+            executePutMappingRequests(totalRequest, node, listener);
+
+            latch.await();
+            assertEquals(totalRequest, successfulRequest.get());
+        } finally {
+            clusterSettingCleanUp();
+        }
+    }
+
+    /*
+     * This will test the timeout of tasks during throttling.
+     *
+     * Here we will assert the client behaviour that client's request is not
+     * failed with throttling exception but timeout exception.
+     * It also verifies that if limit is set to 0, all tasks are getting timedout.
+     */
+
+    public void testTimeoutWhileThrottling() throws Exception {
+        try {
+            internalCluster().beforeTest(random());
+            String node = internalCluster().startNode();
+            int throttlingLimit = 0; // throttle all the tasks
+            createIndex("test");
+            setPutMappingThrottlingLimit(throttlingLimit);
+
+            AtomicInteger timedoutRequest = new AtomicInteger();
+            int totalRequest = randomIntBetween(1, 5);
+            CountDownLatch latch = new CountDownLatch(totalRequest);
+
+            ActionListener listener = new ActionListener() {
+                @Override
+                public void onResponse(Object o) {
+                    latch.countDown();
+                    throw new AssertionError("Request should not succeed");
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    timedoutRequest.incrementAndGet();
+                    latch.countDown();
+                    assertTrue(e instanceof ProcessClusterEventTimeoutException);
+                }
+            };
+            executePutMappingRequests(totalRequest, node, listener);
+
+            latch.await();
+            assertEquals(totalRequest, timedoutRequest.get()); // verifying all requests were timed out with 0 throttling limit
+        } finally {
+            clusterSettingCleanUp();
+        }
+    }
+
+    private void executePutMappingRequests(int totalRequest, String node, ActionListener listener) throws Exception {
+        Thread[] threads = new Thread[totalRequest];
+        for (int i = 0; i < totalRequest; i++) {
+            PutMappingRequest putMappingRequest = new PutMappingRequest("test").source("field" + i, "type=text");
+            threads[i] = new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    internalCluster().client(node).admin().indices().putMapping(putMappingRequest, listener);
+                }
+            });
+        }
+        for (int i = 0; i < totalRequest; i++) {
+            threads[i].run();
+        }
+        for (int i = 0; i < totalRequest; i++) {
+            threads[i].join();
+        }
+    }
+
+    private void setPutMappingThrottlingLimit(int throttlingLimit) {
+        ClusterUpdateSettingsRequest settingsRequest = new ClusterUpdateSettingsRequest();
+        Settings settings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", throttlingLimit).build();
+        settingsRequest.transientSettings(settings);
+        assertAcked(client().admin().cluster().updateSettings(settingsRequest).actionGet());
+    }
+
+    private void clusterSettingCleanUp() {
+        // We need to remove the throttling limit from setting as part of test cleanup
+        ClusterUpdateSettingsRequest settingsRequest = new ClusterUpdateSettingsRequest();
+        Settings settings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", (String) null).build();
+        settingsRequest.transientSettings(settings);
+        assertAcked(client().admin().cluster().updateSettings(settingsRequest).actionGet());
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/common/settings/ConsistentSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/common/settings/ConsistentSettingsIT.java
index 0ffddf815c40b..f8f56cf05fbea 100644
--- a/server/src/internalClusterTest/java/org/opensearch/common/settings/ConsistentSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/common/settings/ConsistentSettingsIT.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Setting.AffixSetting;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
diff --git a/server/src/internalClusterTest/java/org/opensearch/common/settings/UpgradeSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/common/settings/UpgradeSettingsIT.java
index 3c8f914ba4f2f..da0ad316db874 100644
--- a/server/src/internalClusterTest/java/org/opensearch/common/settings/UpgradeSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/common/settings/UpgradeSettingsIT.java
@@ -37,7 +37,6 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
-
 import org.junit.After;
 
 import java.util.Arrays;
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionCleanSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionCleanSettingsIT.java
index 61a47d2bb0237..39a4f2aa82828 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionCleanSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionCleanSettingsIT.java
@@ -32,19 +32,20 @@
 
 package org.opensearch.discovery;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.List;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.store.IndicesStoreIntegrationIT;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -63,7 +64,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     public void testSearchWithRelocationAndSlowClusterStateProcessing() throws Exception {
         // Don't use AbstractDisruptionTestCase.DEFAULT_SETTINGS as settings
         // (which can cause node disconnects on a slow CI machine)
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String node_1 = internalCluster().startDataOnlyNode();
 
         logger.info("--> creating index [test] with one shard and on replica");
@@ -80,7 +81,7 @@ public void testSearchWithRelocationAndSlowClusterStateProcessing() throws Excep
         final String node_2 = internalCluster().startDataOnlyNode();
         List<IndexRequestBuilder> indexRequestBuilderList = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
-            indexRequestBuilderList.add(client().prepareIndex().setIndex("test").setSource("{\"int_field\":1}", XContentType.JSON));
+            indexRequestBuilderList.add(client().prepareIndex().setIndex("test").setSource("{\"int_field\":1}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, indexRequestBuilderList);
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionIT.java
index ceec1315a9d59..38b86d307d197 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionIT.java
@@ -34,9 +34,7 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.index.CorruptIndexException;
-
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -53,13 +51,14 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.disruption.NetworkDisruption;
 import org.opensearch.test.disruption.NetworkDisruption.Bridge;
 import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
@@ -173,7 +172,10 @@ public void testAckedIndexing() throws Exception {
                                 logger.trace("[{}] indexing id [{}] through node [{}] targeting shard [{}]", name, id, node, shard);
                                 IndexRequestBuilder indexRequestBuilder = client.prepareIndex("test")
                                     .setId(id)
-                                    .setSource(Collections.singletonMap(randomFrom(fieldNames), randomNonNegativeLong()), XContentType.JSON)
+                                    .setSource(
+                                        Collections.singletonMap(randomFrom(fieldNames), randomNonNegativeLong()),
+                                        MediaTypeRegistry.JSON
+                                    )
                                     .setTimeout(timeout);
 
                                 if (conflictMode == ConflictMode.external) {
@@ -240,7 +242,7 @@ public void testAckedIndexing() throws Exception {
                         node
                     );
                 }
-                // in case of a bridge partition, shard allocation can fail "index.allocation.max_retries" times if the master
+                // in case of a bridge partition, shard allocation can fail "index.allocation.max_retries" times if the cluster-manager
                 // is the super-connected node and recovery source and target are on opposite sides of the bridge
                 if (disruptionScheme instanceof NetworkDisruption
                     && ((NetworkDisruption) disruptionScheme).getDisruptedLinks() instanceof Bridge) {
@@ -338,26 +340,26 @@ public void testRejoinDocumentExistsInAllShardCopies() throws Exception {
     // simulate handling of sending shard failure during an isolation
     public void testSendingShardFailure() throws Exception {
         List<String> nodes = startCluster(3);
-        String masterNode = internalCluster().getMasterName();
-        List<String> nonMasterNodes = nodes.stream().filter(node -> !node.equals(masterNode)).collect(Collectors.toList());
-        String nonMasterNode = randomFrom(nonMasterNodes);
+        String clusterManagerNode = internalCluster().getClusterManagerName();
+        List<String> nonClusterManagerNodes = nodes.stream().filter(node -> !node.equals(clusterManagerNode)).collect(Collectors.toList());
+        String nonClusterManagerNode = randomFrom(nonClusterManagerNodes);
         assertAcked(
             prepareCreate("test").setSettings(
                 Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
             )
         );
         ensureGreen();
-        String nonMasterNodeId = internalCluster().clusterService(nonMasterNode).localNode().getId();
+        String nonClusterManagerNodeId = internalCluster().clusterService(nonClusterManagerNode).localNode().getId();
 
         // fail a random shard
         ShardRouting failedShard = randomFrom(
-            clusterService().state().getRoutingNodes().node(nonMasterNodeId).shardsWithState(ShardRoutingState.STARTED)
+            clusterService().state().getRoutingNodes().node(nonClusterManagerNodeId).shardsWithState(ShardRoutingState.STARTED)
         );
-        ShardStateAction service = internalCluster().getInstance(ShardStateAction.class, nonMasterNode);
+        ShardStateAction service = internalCluster().getInstance(ShardStateAction.class, nonClusterManagerNode);
         CountDownLatch latch = new CountDownLatch(1);
         AtomicBoolean success = new AtomicBoolean();
 
-        String isolatedNode = randomBoolean() ? masterNode : nonMasterNode;
+        String isolatedNode = randomBoolean() ? clusterManagerNode : nonClusterManagerNode;
         TwoPartitions partitions = isolateNode(isolatedNode);
         // we cannot use the NetworkUnresponsive disruption type here as it will swallow the "shard failed" request, calling neither
         // onSuccess nor onFailure on the provided listener.
@@ -385,10 +387,10 @@ public void onFailure(Exception e) {
             }
         );
 
-        if (isolatedNode.equals(nonMasterNode)) {
-            assertNoMaster(nonMasterNode);
+        if (isolatedNode.equals(nonClusterManagerNode)) {
+            assertNoClusterManager(nonClusterManagerNode);
         } else {
-            ensureStableCluster(2, nonMasterNode);
+            ensureStableCluster(2, nonClusterManagerNode);
         }
 
         // heal the partition
@@ -409,11 +411,11 @@ public void onFailure(Exception e) {
         }
     }
 
-    public void testCannotJoinIfMasterLostDataFolder() throws Exception {
-        String masterNode = internalCluster().startMasterOnlyNode();
+    public void testCannotJoinIfClusterManagerLostDataFolder() throws Exception {
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         String dataNode = internalCluster().startDataOnlyNode();
 
-        internalCluster().restartNode(masterNode, new InternalTestCluster.RestartCallback() {
+        internalCluster().restartNode(clusterManagerNode, new InternalTestCluster.RestartCallback() {
             @Override
             public boolean clearData(String nodeName) {
                 return true;
@@ -424,7 +426,7 @@ public Settings onNodeStopped(String nodeName) {
                 return Settings.builder()
                     .put(ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), nodeName)
                     /*
-                     * the data node might join while the master is still not fully established as master just yet and bypasses the join
+                     * the data node might join while the cluster-manager is still not fully established as cluster-manager just yet and bypasses the join
                      * validation that is done before adding the node to the cluster. Only the join validation when handling the publish
                      * request takes place, but at this point the cluster state has been successfully committed, and will subsequently be
                      * exposed to the applier. The health check below therefore sees the cluster state with the 2 nodes and thinks all is
@@ -442,9 +444,9 @@ public boolean validateClusterForming() {
         });
 
         assertBusy(() -> {
-            assertFalse(internalCluster().client(masterNode).admin().cluster().prepareHealth().get().isTimedOut());
+            assertFalse(internalCluster().client(clusterManagerNode).admin().cluster().prepareHealth().get().isTimedOut());
             assertTrue(
-                internalCluster().client(masterNode)
+                internalCluster().client(clusterManagerNode)
                     .admin()
                     .cluster()
                     .prepareHealth()
@@ -458,34 +460,35 @@ public boolean validateClusterForming() {
     }
 
     /**
-     * Tests that indices are properly deleted even if there is a master transition in between.
+     * Tests that indices are properly deleted even if there is a cluster-manager transition in between.
      * Test for https://github.com/elastic/elasticsearch/issues/11665
      */
     public void testIndicesDeleted() throws Exception {
         final String idxName = "test";
-        final List<String> allMasterEligibleNodes = internalCluster().startMasterOnlyNodes(2);
+        final List<String> allClusterManagerEligibleNodes = internalCluster().startClusterManagerOnlyNodes(2);
         final String dataNode = internalCluster().startDataOnlyNode();
         ensureStableCluster(3);
         assertAcked(prepareCreate("test"));
 
-        final String masterNode1 = internalCluster().getMasterName();
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
         NetworkDisruption networkDisruption = new NetworkDisruption(
-            new TwoPartitions(masterNode1, dataNode),
+            new TwoPartitions(clusterManagerNode1, dataNode),
             NetworkDisruption.UNRESPONSIVE
         );
         internalCluster().setDisruptionScheme(networkDisruption);
         networkDisruption.startDisrupting();
         // We know this will time out due to the partition, we check manually below to not proceed until
-        // the delete has been applied to the master node and the master eligible node.
-        internalCluster().client(masterNode1).admin().indices().prepareDelete(idxName).setTimeout("0s").get();
-        // Don't restart the master node until we know the index deletion has taken effect on master and the master eligible node.
+        // the delete has been applied to the cluster-manager node and the cluster-manager eligible node.
+        internalCluster().client(clusterManagerNode1).admin().indices().prepareDelete(idxName).setTimeout("0s").get();
+        // Don't restart the cluster-manager node until we know the index deletion has taken effect on cluster-manager and the
+        // cluster-manager eligible node.
         assertBusy(() -> {
-            for (String masterNode : allMasterEligibleNodes) {
-                final ClusterState masterState = internalCluster().clusterService(masterNode).state();
-                assertTrue("index not deleted on " + masterNode, masterState.metadata().hasIndex(idxName) == false);
+            for (String clusterManagerNode : allClusterManagerEligibleNodes) {
+                final ClusterState clusterManagerState = internalCluster().clusterService(clusterManagerNode).state();
+                assertTrue("index not deleted on " + clusterManagerNode, clusterManagerState.metadata().hasIndex(idxName) == false);
             }
         });
-        internalCluster().restartNode(masterNode1, InternalTestCluster.EMPTY_CALLBACK);
+        internalCluster().restartNode(clusterManagerNode1, InternalTestCluster.EMPTY_CALLBACK);
         ensureYellow();
         assertFalse(client().admin().indices().prepareExists(idxName).get().isExists());
     }
@@ -514,7 +517,10 @@ public void testRestartNodeWhileIndexing() throws Exception {
                     try {
                         IndexResponse response = client().prepareIndex(index)
                             .setId(id)
-                            .setSource(Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()), XContentType.JSON)
+                            .setSource(
+                                Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()),
+                                MediaTypeRegistry.JSON
+                            )
                             .get();
                         assertThat(response.getResult(), is(oneOf(CREATED, UPDATED)));
                         logger.info("--> index id={} seq_no={}", response.getId(), response.getSeqNo());
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterManagerDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterManagerDisruptionIT.java
new file mode 100644
index 0000000000000..f0d52405efac6
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/ClusterManagerDisruptionIT.java
@@ -0,0 +1,345 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery;
+
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.action.admin.indices.stats.ShardStats;
+import org.opensearch.action.bulk.BulkRequestBuilder;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.BlockClusterManagerServiceOnClusterManager;
+import org.opensearch.test.disruption.IntermittentLongGCDisruption;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
+import org.opensearch.test.disruption.ServiceDisruptionScheme;
+import org.opensearch.test.disruption.SingleNodeDisruption;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
+
+/**
+ * Tests relating to the loss of the cluster-manager.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class ClusterManagerDisruptionIT extends AbstractDisruptionTestCase {
+
+    /**
+     * Test that cluster recovers from a long GC on cluster-manager that causes other nodes to elect a new one
+     */
+    public void testClusterManagerNodeGCs() throws Exception {
+        List<String> nodes = startCluster(3);
+
+        String oldClusterManagerNode = internalCluster().getClusterManagerName();
+        // a very long GC, but it's OK as we remove the disruption when it has had an effect
+        SingleNodeDisruption clusterManagerNodeDisruption = new IntermittentLongGCDisruption(
+            random(),
+            oldClusterManagerNode,
+            100,
+            200,
+            30000,
+            60000
+        );
+        internalCluster().setDisruptionScheme(clusterManagerNodeDisruption);
+        clusterManagerNodeDisruption.startDisrupting();
+
+        Set<String> oldNonClusterManagerNodesSet = new HashSet<>(nodes);
+        oldNonClusterManagerNodesSet.remove(oldClusterManagerNode);
+
+        List<String> oldNonClusterManagerNodes = new ArrayList<>(oldNonClusterManagerNodesSet);
+
+        logger.info("waiting for nodes to de-elect cluster-manager [{}]", oldClusterManagerNode);
+        for (String node : oldNonClusterManagerNodesSet) {
+            assertDifferentClusterManager(node, oldClusterManagerNode);
+        }
+
+        logger.info("waiting for nodes to elect a new cluster-manager");
+        ensureStableCluster(2, oldNonClusterManagerNodes.get(0));
+
+        // restore GC
+        clusterManagerNodeDisruption.stopDisrupting();
+        final TimeValue waitTime = new TimeValue(
+            DISRUPTION_HEALING_OVERHEAD.millis() + clusterManagerNodeDisruption.expectedTimeToHeal().millis()
+        );
+        ensureStableCluster(3, waitTime, false, oldNonClusterManagerNodes.get(0));
+
+        // make sure all nodes agree on cluster-manager
+        String newClusterManager = internalCluster().getClusterManagerName();
+        assertThat(newClusterManager, not(equalTo(oldClusterManagerNode)));
+        assertClusterManager(newClusterManager, nodes);
+    }
+
+    /**
+     * This test isolates the cluster-manager from rest of the cluster, waits for a new cluster-manager to be elected, restores the partition
+     * and verifies that all node agree on the new cluster state
+     */
+    public void testIsolateClusterManagerAndVerifyClusterStateConsensus() throws Exception {
+        final List<String> nodes = startCluster(3);
+
+        assertAcked(
+            prepareCreate("test").setSettings(
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1 + randomInt(2))
+                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, randomInt(2))
+            )
+        );
+
+        ensureGreen();
+        String isolatedNode = internalCluster().getClusterManagerName();
+        TwoPartitions partitions = isolateNode(isolatedNode);
+        NetworkDisruption networkDisruption = addRandomDisruptionType(partitions);
+        networkDisruption.startDisrupting();
+
+        String nonIsolatedNode = partitions.getMajoritySide().iterator().next();
+
+        // make sure cluster reforms
+        ensureStableCluster(2, nonIsolatedNode);
+
+        // make sure isolated need picks up on things.
+        assertNoClusterManager(isolatedNode, TimeValue.timeValueSeconds(40));
+
+        // restore isolation
+        networkDisruption.stopDisrupting();
+
+        for (String node : nodes) {
+            ensureStableCluster(
+                3,
+                new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + networkDisruption.expectedTimeToHeal().millis()),
+                true,
+                node
+            );
+        }
+
+        logger.info("issue a reroute");
+        // trigger a reroute now, instead of waiting for the background reroute of RerouteService
+        assertAcked(client().admin().cluster().prepareReroute());
+        // and wait for it to finish and for the cluster to stabilize
+        ensureGreen("test");
+
+        // verify all cluster states are the same
+        // use assert busy to wait for cluster states to be applied (as publish_timeout has low value)
+        assertBusy(() -> {
+            ClusterState state = null;
+            for (String node : nodes) {
+                ClusterState nodeState = getNodeClusterState(node);
+                if (state == null) {
+                    state = nodeState;
+                    continue;
+                }
+                // assert nodes are identical
+                try {
+                    assertEquals("unequal versions", state.version(), nodeState.version());
+                    assertEquals("unequal node count", state.nodes().getSize(), nodeState.nodes().getSize());
+                    assertEquals(
+                        "different cluster-managers ",
+                        state.nodes().getClusterManagerNodeId(),
+                        nodeState.nodes().getClusterManagerNodeId()
+                    );
+                    assertEquals("different meta data version", state.metadata().version(), nodeState.metadata().version());
+                    assertEquals("different routing", state.routingTable().toString(), nodeState.routingTable().toString());
+                } catch (AssertionError t) {
+                    fail(
+                        "failed comparing cluster state: "
+                            + t.getMessage()
+                            + "\n"
+                            + "--- cluster state of node ["
+                            + nodes.get(0)
+                            + "]: ---\n"
+                            + state
+                            + "\n--- cluster state ["
+                            + node
+                            + "]: ---\n"
+                            + nodeState
+                    );
+                }
+
+            }
+        });
+    }
+
+    /**
+     * Verify that the proper block is applied when nodes lose their cluster-manager
+     */
+    public void testVerifyApiBlocksDuringPartition() throws Exception {
+        internalCluster().startNodes(
+            3,
+            Settings.builder().putNull(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey()).build()
+        );
+
+        // Makes sure that the get request can be executed on each node locally:
+        assertAcked(
+            prepareCreate("test").setSettings(
+                Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+            )
+        );
+
+        // Everything is stable now, it is now time to simulate evil...
+        // but first make sure we have no initializing shards and all is green
+        // (waiting for green here, because indexing / search in a yellow index is fine as long as no other nodes go down)
+        ensureGreen("test");
+
+        TwoPartitions partitions = TwoPartitions.random(random(), internalCluster().getNodeNames());
+        NetworkDisruption networkDisruption = addRandomDisruptionType(partitions);
+
+        assertEquals(1, partitions.getMinoritySide().size());
+        final String isolatedNode = partitions.getMinoritySide().iterator().next();
+        assertEquals(2, partitions.getMajoritySide().size());
+        final String nonIsolatedNode = partitions.getMajoritySide().iterator().next();
+
+        // Simulate a network issue between the unlucky node and the rest of the cluster.
+        networkDisruption.startDisrupting();
+
+        // The unlucky node must report *no* cluster-manager node, since it can't connect to cluster-manager and in fact it should
+        // continuously ping until network failures have been resolved. However
+        // It may a take a bit before the node detects it has been cut off from the elected cluster-manager
+        logger.info("waiting for isolated node [{}] to have no cluster-manager", isolatedNode);
+        assertNoClusterManager(
+            isolatedNode,
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES,
+            TimeValue.timeValueSeconds(30)
+        );
+
+        logger.info("wait until elected cluster-manager has been removed and a new 2 node cluster was from (via [{}])", isolatedNode);
+        ensureStableCluster(2, nonIsolatedNode);
+
+        for (String node : partitions.getMajoritySide()) {
+            ClusterState nodeState = getNodeClusterState(node);
+            boolean success = true;
+            if (nodeState.nodes().getClusterManagerNode() == null) {
+                success = false;
+            }
+            if (!nodeState.blocks().global().isEmpty()) {
+                success = false;
+            }
+            if (!success) {
+                fail(
+                    "node ["
+                        + node
+                        + "] has no cluster-manager or has blocks, despite of being on the right side of the partition. State dump:\n"
+                        + nodeState
+                );
+            }
+        }
+
+        networkDisruption.stopDisrupting();
+
+        // Wait until the cluster-manager node sees al 3 nodes again.
+        ensureStableCluster(3, new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + networkDisruption.expectedTimeToHeal().millis()));
+
+        logger.info(
+            "Verify no cluster-manager block with {} set to {}",
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(),
+            "all"
+        );
+        client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all"))
+            .get();
+
+        networkDisruption.startDisrupting();
+
+        // The unlucky node must report *no* cluster-manager node, since it can't connect to cluster-manager and in fact it should
+        // continuously ping until network failures have been resolved. However
+        // It may a take a bit before the node detects it has been cut off from the elected cluster-manager
+        logger.info("waiting for isolated node [{}] to have no cluster-manager", isolatedNode);
+        assertNoClusterManager(isolatedNode, NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL, TimeValue.timeValueSeconds(30));
+
+        // make sure we have stable cluster & cross partition recoveries are canceled by the removal of the missing node
+        // the unresponsive partition causes recoveries to only time out after 15m (default) and these will cause
+        // the test to fail due to unfreed resources
+        ensureStableCluster(2, nonIsolatedNode);
+
+    }
+
+    public void testMappingTimeout() throws Exception {
+        startCluster(3);
+        createIndex(
+            "test",
+            Settings.builder()
+                .put("index.number_of_shards", 1)
+                .put("index.number_of_replicas", 1)
+                .put("index.routing.allocation.exclude._name", internalCluster().getClusterManagerName())
+                .build()
+        );
+
+        // create one field
+        index("test", "doc", "1", "{ \"f\": 1 }");
+
+        ensureGreen();
+
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(Settings.builder().put("indices.mapping.dynamic_timeout", "1ms"))
+        );
+
+        ServiceDisruptionScheme disruption = new BlockClusterManagerServiceOnClusterManager(random());
+        setDisruptionScheme(disruption);
+
+        disruption.startDisrupting();
+
+        BulkRequestBuilder bulk = client().prepareBulk();
+        bulk.add(client().prepareIndex("test").setId("2").setSource("{ \"f\": 1 }", MediaTypeRegistry.JSON));
+        bulk.add(client().prepareIndex("test").setId("3").setSource("{ \"g\": 1 }", MediaTypeRegistry.JSON));
+        bulk.add(client().prepareIndex("test").setId("4").setSource("{ \"f\": 1 }", MediaTypeRegistry.JSON));
+        BulkResponse bulkResponse = bulk.get();
+        assertTrue(bulkResponse.hasFailures());
+
+        disruption.stopDisrupting();
+
+        assertBusy(() -> {
+            IndicesStatsResponse stats = client().admin().indices().prepareStats("test").clear().get();
+            for (ShardStats shardStats : stats.getShards()) {
+                assertThat(
+                    shardStats.getShardRouting().toString(),
+                    shardStats.getSeqNoStats().getGlobalCheckpoint(),
+                    equalTo(shardStats.getSeqNoStats().getLocalCheckpoint())
+                );
+            }
+        });
+
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/DiscoveryDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/DiscoveryDisruptionIT.java
index 079aaa714a15c..a2864b6dfd1da 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/DiscoveryDisruptionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/DiscoveryDisruptionIT.java
@@ -64,62 +64,79 @@ public class DiscoveryDisruptionIT extends AbstractDisruptionTestCase {
      * Test cluster join with issues in cluster state publishing *
      */
     public void testClusterJoinDespiteOfPublishingIssues() throws Exception {
-        String masterNode = internalCluster().startMasterOnlyNode();
-        String nonMasterNode = internalCluster().startDataOnlyNode();
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        String nonClusterManagerNode = internalCluster().startDataOnlyNode();
 
-        DiscoveryNodes discoveryNodes = internalCluster().getInstance(ClusterService.class, nonMasterNode).state().nodes();
+        DiscoveryNodes discoveryNodes = internalCluster().getInstance(ClusterService.class, nonClusterManagerNode).state().nodes();
 
-        TransportService masterTranspotService = internalCluster().getInstance(
+        TransportService clusterManagerTranspotService = internalCluster().getInstance(
             TransportService.class,
-            discoveryNodes.getMasterNode().getName()
+            discoveryNodes.getClusterManagerNode().getName()
         );
 
-        logger.info("blocking requests from non master [{}] to master [{}]", nonMasterNode, masterNode);
-        MockTransportService nonMasterTransportService = (MockTransportService) internalCluster().getInstance(
+        logger.info("blocking requests from non cluster-manager [{}] to cluster-manager [{}]", nonClusterManagerNode, clusterManagerNode);
+        MockTransportService nonClusterManagerTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            nonMasterNode
+            nonClusterManagerNode
         );
-        nonMasterTransportService.addFailToSendNoConnectRule(masterTranspotService);
+        nonClusterManagerTransportService.addFailToSendNoConnectRule(clusterManagerTranspotService);
 
-        assertNoMaster(nonMasterNode);
+        assertNoClusterManager(nonClusterManagerNode);
 
-        logger.info("blocking cluster state publishing from master [{}] to non master [{}]", masterNode, nonMasterNode);
-        MockTransportService masterTransportService = (MockTransportService) internalCluster().getInstance(
+        logger.info(
+            "blocking cluster state publishing from cluster-manager [{}] to non cluster-manager [{}]",
+            clusterManagerNode,
+            nonClusterManagerNode
+        );
+        MockTransportService clusterManagerTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            masterNode
+            clusterManagerNode
         );
         TransportService localTransportService = internalCluster().getInstance(
             TransportService.class,
             discoveryNodes.getLocalNode().getName()
         );
         if (randomBoolean()) {
-            masterTransportService.addFailToSendNoConnectRule(localTransportService, PublicationTransportHandler.PUBLISH_STATE_ACTION_NAME);
+            clusterManagerTransportService.addFailToSendNoConnectRule(
+                localTransportService,
+                PublicationTransportHandler.PUBLISH_STATE_ACTION_NAME
+            );
         } else {
-            masterTransportService.addFailToSendNoConnectRule(localTransportService, PublicationTransportHandler.COMMIT_STATE_ACTION_NAME);
+            clusterManagerTransportService.addFailToSendNoConnectRule(
+                localTransportService,
+                PublicationTransportHandler.COMMIT_STATE_ACTION_NAME
+            );
         }
 
-        logger.info("allowing requests from non master [{}] to master [{}], waiting for two join request", nonMasterNode, masterNode);
+        logger.info(
+            "allowing requests from non cluster-manager [{}] to cluster-manager [{}], waiting for two join request",
+            nonClusterManagerNode,
+            clusterManagerNode
+        );
         final CountDownLatch countDownLatch = new CountDownLatch(2);
-        nonMasterTransportService.addSendBehavior(masterTransportService, (connection, requestId, action, request, options) -> {
-            if (action.equals(JoinHelper.JOIN_ACTION_NAME)) {
-                countDownLatch.countDown();
+        nonClusterManagerTransportService.addSendBehavior(
+            clusterManagerTransportService,
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(JoinHelper.JOIN_ACTION_NAME)) {
+                    countDownLatch.countDown();
+                }
+                connection.sendRequest(requestId, action, request, options);
             }
-            connection.sendRequest(requestId, action, request, options);
-        });
+        );
 
-        nonMasterTransportService.addConnectBehavior(masterTransportService, Transport::openConnection);
+        nonClusterManagerTransportService.addConnectBehavior(clusterManagerTransportService, Transport::openConnection);
 
         countDownLatch.await();
 
         logger.info("waiting for cluster to reform");
-        masterTransportService.clearOutboundRules(localTransportService);
-        nonMasterTransportService.clearOutboundRules(localTransportService);
+        clusterManagerTransportService.clearOutboundRules(localTransportService);
+        nonClusterManagerTransportService.clearOutboundRules(localTransportService);
 
         ensureStableCluster(2);
 
         // shutting down the nodes, to avoid the leakage check tripping
         // on the states associated with the commit requests we may have dropped
-        internalCluster().stopRandomNonMasterNode();
+        internalCluster().stopRandomNonClusterManagerNode();
     }
 
     public void testClusterFormingWithASlowNode() {
@@ -137,7 +154,7 @@ public void testClusterFormingWithASlowNode() {
         ensureStableCluster(3);
     }
 
-    public void testElectMasterWithLatestVersion() throws Exception {
+    public void testElectClusterManagerWithLatestVersion() throws Exception {
         final Set<String> nodes = new HashSet<>(internalCluster().startNodes(3));
         ensureStableCluster(3);
         ServiceDisruptionScheme isolateAllNodes = new NetworkDisruption(
@@ -146,22 +163,22 @@ public void testElectMasterWithLatestVersion() throws Exception {
         );
         internalCluster().setDisruptionScheme(isolateAllNodes);
 
-        logger.info("--> forcing a complete election to make sure \"preferred\" master is elected");
+        logger.info("--> forcing a complete election to make sure \"preferred\" cluster-manager is elected");
         isolateAllNodes.startDisrupting();
         for (String node : nodes) {
-            assertNoMaster(node);
+            assertNoClusterManager(node);
         }
         internalCluster().clearDisruptionScheme();
         ensureStableCluster(3);
-        final String preferredMasterName = internalCluster().getMasterName();
-        final DiscoveryNode preferredMaster = internalCluster().clusterService(preferredMasterName).localNode();
+        final String preferredClusterManagerName = internalCluster().getClusterManagerName();
+        final DiscoveryNode preferredClusterManager = internalCluster().clusterService(preferredClusterManagerName).localNode();
 
-        logger.info("--> preferred master is {}", preferredMaster);
+        logger.info("--> preferred cluster-manager is {}", preferredClusterManager);
         final Set<String> nonPreferredNodes = new HashSet<>(nodes);
-        nonPreferredNodes.remove(preferredMasterName);
-        final ServiceDisruptionScheme isolatePreferredMaster = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
-        internalCluster().setDisruptionScheme(isolatePreferredMaster);
-        isolatePreferredMaster.startDisrupting();
+        nonPreferredNodes.remove(preferredClusterManagerName);
+        final ServiceDisruptionScheme isolatePreferredClusterManager = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
+        internalCluster().setDisruptionScheme(isolatePreferredClusterManager);
+        isolatePreferredClusterManager.startDisrupting();
 
         client(randomFrom(nonPreferredNodes)).admin()
             .indices()
@@ -177,7 +194,7 @@ public void testElectMasterWithLatestVersion() throws Exception {
         logger.info("--> forcing a complete election again");
         isolateAllNodes.startDisrupting();
         for (String node : nodes) {
-            assertNoMaster(node);
+            assertNoClusterManager(node);
         }
 
         isolateAllNodes.stopDisrupting();
@@ -190,41 +207,45 @@ public void testElectMasterWithLatestVersion() throws Exception {
     }
 
     /**
-     * Adds an asymmetric break between a master and one of the nodes and makes
+     * Adds an asymmetric break between a cluster-manager and one of the nodes and makes
      * sure that the node is removed form the cluster, that the node start pinging and that
      * the cluster reforms when healed.
      */
-    public void testNodeNotReachableFromMaster() throws Exception {
+    public void testNodeNotReachableFromClusterManager() throws Exception {
         startCluster(3);
 
-        String masterNode = internalCluster().getMasterName();
-        String nonMasterNode = null;
-        while (nonMasterNode == null) {
-            nonMasterNode = randomFrom(internalCluster().getNodeNames());
-            if (nonMasterNode.equals(masterNode)) {
-                nonMasterNode = null;
+        String clusterManagerNode = internalCluster().getClusterManagerName();
+        String nonClusterManagerNode = null;
+        while (nonClusterManagerNode == null) {
+            nonClusterManagerNode = randomFrom(internalCluster().getNodeNames());
+            if (nonClusterManagerNode.equals(clusterManagerNode)) {
+                nonClusterManagerNode = null;
             }
         }
 
-        logger.info("blocking request from master [{}] to [{}]", masterNode, nonMasterNode);
-        MockTransportService masterTransportService = (MockTransportService) internalCluster().getInstance(
+        logger.info("blocking request from cluster-manager [{}] to [{}]", clusterManagerNode, nonClusterManagerNode);
+        MockTransportService clusterManagerTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            masterNode
+            clusterManagerNode
         );
         if (randomBoolean()) {
-            masterTransportService.addUnresponsiveRule(internalCluster().getInstance(TransportService.class, nonMasterNode));
+            clusterManagerTransportService.addUnresponsiveRule(
+                internalCluster().getInstance(TransportService.class, nonClusterManagerNode)
+            );
         } else {
-            masterTransportService.addFailToSendNoConnectRule(internalCluster().getInstance(TransportService.class, nonMasterNode));
+            clusterManagerTransportService.addFailToSendNoConnectRule(
+                internalCluster().getInstance(TransportService.class, nonClusterManagerNode)
+            );
         }
 
-        logger.info("waiting for [{}] to be removed from cluster", nonMasterNode);
-        ensureStableCluster(2, masterNode);
+        logger.info("waiting for [{}] to be removed from cluster", nonClusterManagerNode);
+        ensureStableCluster(2, clusterManagerNode);
 
-        logger.info("waiting for [{}] to have no master", nonMasterNode);
-        assertNoMaster(nonMasterNode);
+        logger.info("waiting for [{}] to have no cluster-manager", nonClusterManagerNode);
+        assertNoClusterManager(nonClusterManagerNode);
 
         logger.info("healing partition and checking cluster reforms");
-        masterTransportService.clearAllRules();
+        clusterManagerTransportService.clearAllRules();
 
         ensureStableCluster(3);
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/DiskDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/DiskDisruptionIT.java
index ef00150b7c814..b7aae73056f6f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/DiskDisruptionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/DiskDisruptionIT.java
@@ -32,6 +32,7 @@
 package org.opensearch.discovery;
 
 import com.carrotsearch.randomizedtesting.RandomizedTest;
+
 import org.apache.lucene.tests.mockfile.FilterFileSystemProvider;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -41,9 +42,8 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.test.BackgroundIndexer;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/MasterDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/MasterDisruptionIT.java
deleted file mode 100644
index 14e7a26bb448e..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/MasterDisruptionIT.java
+++ /dev/null
@@ -1,321 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.discovery;
-
-import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
-import org.opensearch.action.admin.indices.stats.ShardStats;
-import org.opensearch.action.bulk.BulkRequestBuilder;
-import org.opensearch.action.bulk.BulkResponse;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.disruption.BlockMasterServiceOnMaster;
-import org.opensearch.test.disruption.IntermittentLongGCDisruption;
-import org.opensearch.test.disruption.NetworkDisruption;
-import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
-import org.opensearch.test.disruption.ServiceDisruptionScheme;
-import org.opensearch.test.disruption.SingleNodeDisruption;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.not;
-
-/**
- * Tests relating to the loss of the master.
- */
-@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
-public class MasterDisruptionIT extends AbstractDisruptionTestCase {
-
-    /**
-     * Test that cluster recovers from a long GC on master that causes other nodes to elect a new one
-     */
-    public void testMasterNodeGCs() throws Exception {
-        List<String> nodes = startCluster(3);
-
-        String oldMasterNode = internalCluster().getMasterName();
-        // a very long GC, but it's OK as we remove the disruption when it has had an effect
-        SingleNodeDisruption masterNodeDisruption = new IntermittentLongGCDisruption(random(), oldMasterNode, 100, 200, 30000, 60000);
-        internalCluster().setDisruptionScheme(masterNodeDisruption);
-        masterNodeDisruption.startDisrupting();
-
-        Set<String> oldNonMasterNodesSet = new HashSet<>(nodes);
-        oldNonMasterNodesSet.remove(oldMasterNode);
-
-        List<String> oldNonMasterNodes = new ArrayList<>(oldNonMasterNodesSet);
-
-        logger.info("waiting for nodes to de-elect master [{}]", oldMasterNode);
-        for (String node : oldNonMasterNodesSet) {
-            assertDifferentMaster(node, oldMasterNode);
-        }
-
-        logger.info("waiting for nodes to elect a new master");
-        ensureStableCluster(2, oldNonMasterNodes.get(0));
-
-        // restore GC
-        masterNodeDisruption.stopDisrupting();
-        final TimeValue waitTime = new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + masterNodeDisruption.expectedTimeToHeal().millis());
-        ensureStableCluster(3, waitTime, false, oldNonMasterNodes.get(0));
-
-        // make sure all nodes agree on master
-        String newMaster = internalCluster().getMasterName();
-        assertThat(newMaster, not(equalTo(oldMasterNode)));
-        assertMaster(newMaster, nodes);
-    }
-
-    /**
-     * This test isolates the master from rest of the cluster, waits for a new master to be elected, restores the partition
-     * and verifies that all node agree on the new cluster state
-     */
-    public void testIsolateMasterAndVerifyClusterStateConsensus() throws Exception {
-        final List<String> nodes = startCluster(3);
-
-        assertAcked(
-            prepareCreate("test").setSettings(
-                Settings.builder()
-                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1 + randomInt(2))
-                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, randomInt(2))
-            )
-        );
-
-        ensureGreen();
-        String isolatedNode = internalCluster().getMasterName();
-        TwoPartitions partitions = isolateNode(isolatedNode);
-        NetworkDisruption networkDisruption = addRandomDisruptionType(partitions);
-        networkDisruption.startDisrupting();
-
-        String nonIsolatedNode = partitions.getMajoritySide().iterator().next();
-
-        // make sure cluster reforms
-        ensureStableCluster(2, nonIsolatedNode);
-
-        // make sure isolated need picks up on things.
-        assertNoMaster(isolatedNode, TimeValue.timeValueSeconds(40));
-
-        // restore isolation
-        networkDisruption.stopDisrupting();
-
-        for (String node : nodes) {
-            ensureStableCluster(
-                3,
-                new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + networkDisruption.expectedTimeToHeal().millis()),
-                true,
-                node
-            );
-        }
-
-        logger.info("issue a reroute");
-        // trigger a reroute now, instead of waiting for the background reroute of RerouteService
-        assertAcked(client().admin().cluster().prepareReroute());
-        // and wait for it to finish and for the cluster to stabilize
-        ensureGreen("test");
-
-        // verify all cluster states are the same
-        // use assert busy to wait for cluster states to be applied (as publish_timeout has low value)
-        assertBusy(() -> {
-            ClusterState state = null;
-            for (String node : nodes) {
-                ClusterState nodeState = getNodeClusterState(node);
-                if (state == null) {
-                    state = nodeState;
-                    continue;
-                }
-                // assert nodes are identical
-                try {
-                    assertEquals("unequal versions", state.version(), nodeState.version());
-                    assertEquals("unequal node count", state.nodes().getSize(), nodeState.nodes().getSize());
-                    assertEquals("different masters ", state.nodes().getMasterNodeId(), nodeState.nodes().getMasterNodeId());
-                    assertEquals("different meta data version", state.metadata().version(), nodeState.metadata().version());
-                    assertEquals("different routing", state.routingTable().toString(), nodeState.routingTable().toString());
-                } catch (AssertionError t) {
-                    fail(
-                        "failed comparing cluster state: "
-                            + t.getMessage()
-                            + "\n"
-                            + "--- cluster state of node ["
-                            + nodes.get(0)
-                            + "]: ---\n"
-                            + state
-                            + "\n--- cluster state ["
-                            + node
-                            + "]: ---\n"
-                            + nodeState
-                    );
-                }
-
-            }
-        });
-    }
-
-    /**
-     * Verify that the proper block is applied when nodes lose their master
-     */
-    public void testVerifyApiBlocksDuringPartition() throws Exception {
-        internalCluster().startNodes(3, Settings.builder().putNull(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey()).build());
-
-        // Makes sure that the get request can be executed on each node locally:
-        assertAcked(
-            prepareCreate("test").setSettings(
-                Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
-            )
-        );
-
-        // Everything is stable now, it is now time to simulate evil...
-        // but first make sure we have no initializing shards and all is green
-        // (waiting for green here, because indexing / search in a yellow index is fine as long as no other nodes go down)
-        ensureGreen("test");
-
-        TwoPartitions partitions = TwoPartitions.random(random(), internalCluster().getNodeNames());
-        NetworkDisruption networkDisruption = addRandomDisruptionType(partitions);
-
-        assertEquals(1, partitions.getMinoritySide().size());
-        final String isolatedNode = partitions.getMinoritySide().iterator().next();
-        assertEquals(2, partitions.getMajoritySide().size());
-        final String nonIsolatedNode = partitions.getMajoritySide().iterator().next();
-
-        // Simulate a network issue between the unlucky node and the rest of the cluster.
-        networkDisruption.startDisrupting();
-
-        // The unlucky node must report *no* master node, since it can't connect to master and in fact it should
-        // continuously ping until network failures have been resolved. However
-        // It may a take a bit before the node detects it has been cut off from the elected master
-        logger.info("waiting for isolated node [{}] to have no master", isolatedNode);
-        assertNoMaster(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_WRITES, TimeValue.timeValueSeconds(30));
-
-        logger.info("wait until elected master has been removed and a new 2 node cluster was from (via [{}])", isolatedNode);
-        ensureStableCluster(2, nonIsolatedNode);
-
-        for (String node : partitions.getMajoritySide()) {
-            ClusterState nodeState = getNodeClusterState(node);
-            boolean success = true;
-            if (nodeState.nodes().getMasterNode() == null) {
-                success = false;
-            }
-            if (!nodeState.blocks().global().isEmpty()) {
-                success = false;
-            }
-            if (!success) {
-                fail(
-                    "node ["
-                        + node
-                        + "] has no master or has blocks, despite of being on the right side of the partition. State dump:\n"
-                        + nodeState
-                );
-            }
-        }
-
-        networkDisruption.stopDisrupting();
-
-        // Wait until the master node sees al 3 nodes again.
-        ensureStableCluster(3, new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + networkDisruption.expectedTimeToHeal().millis()));
-
-        logger.info("Verify no master block with {} set to {}", NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all");
-        client().admin()
-            .cluster()
-            .prepareUpdateSettings()
-            .setTransientSettings(Settings.builder().put(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all"))
-            .get();
-
-        networkDisruption.startDisrupting();
-
-        // The unlucky node must report *no* master node, since it can't connect to master and in fact it should
-        // continuously ping until network failures have been resolved. However
-        // It may a take a bit before the node detects it has been cut off from the elected master
-        logger.info("waiting for isolated node [{}] to have no master", isolatedNode);
-        assertNoMaster(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_ALL, TimeValue.timeValueSeconds(30));
-
-        // make sure we have stable cluster & cross partition recoveries are canceled by the removal of the missing node
-        // the unresponsive partition causes recoveries to only time out after 15m (default) and these will cause
-        // the test to fail due to unfreed resources
-        ensureStableCluster(2, nonIsolatedNode);
-
-    }
-
-    public void testMappingTimeout() throws Exception {
-        startCluster(3);
-        createIndex(
-            "test",
-            Settings.builder()
-                .put("index.number_of_shards", 1)
-                .put("index.number_of_replicas", 1)
-                .put("index.routing.allocation.exclude._name", internalCluster().getMasterName())
-                .build()
-        );
-
-        // create one field
-        index("test", "doc", "1", "{ \"f\": 1 }");
-
-        ensureGreen();
-
-        assertAcked(
-            client().admin()
-                .cluster()
-                .prepareUpdateSettings()
-                .setTransientSettings(Settings.builder().put("indices.mapping.dynamic_timeout", "1ms"))
-        );
-
-        ServiceDisruptionScheme disruption = new BlockMasterServiceOnMaster(random());
-        setDisruptionScheme(disruption);
-
-        disruption.startDisrupting();
-
-        BulkRequestBuilder bulk = client().prepareBulk();
-        bulk.add(client().prepareIndex("test").setId("2").setSource("{ \"f\": 1 }", XContentType.JSON));
-        bulk.add(client().prepareIndex("test").setId("3").setSource("{ \"g\": 1 }", XContentType.JSON));
-        bulk.add(client().prepareIndex("test").setId("4").setSource("{ \"f\": 1 }", XContentType.JSON));
-        BulkResponse bulkResponse = bulk.get();
-        assertTrue(bulkResponse.hasFailures());
-
-        disruption.stopDisrupting();
-
-        assertBusy(() -> {
-            IndicesStatsResponse stats = client().admin().indices().prepareStats("test").clear().get();
-            for (ShardStats shardStats : stats.getShards()) {
-                assertThat(
-                    shardStats.getShardRouting().toString(),
-                    shardStats.getSeqNoStats().getGlobalCheckpoint(),
-                    equalTo(shardStats.getSeqNoStats().getLocalCheckpoint())
-                );
-            }
-        });
-
-    }
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/SnapshotDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/SnapshotDisruptionIT.java
index 086aeb695c411..68eb367108954 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/SnapshotDisruptionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/SnapshotDisruptionIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.discovery;
 
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -43,6 +42,7 @@
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.json.JsonXContent;
@@ -86,7 +86,7 @@ protected Settings nodeSettings(int nodeOrdinal) {
 
     public void testDisruptionAfterFinalization() throws Exception {
         final String idxName = "test";
-        internalCluster().startMasterOnlyNodes(3);
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         ensureStableCluster(4);
 
@@ -94,12 +94,12 @@ public void testDisruptionAfterFinalization() throws Exception {
 
         createRepository("test-repo", "fs");
 
-        final String masterNode1 = internalCluster().getMasterName();
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
 
-        NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.UNRESPONSIVE);
+        NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.UNRESPONSIVE);
         internalCluster().setDisruptionScheme(networkDisruption);
 
-        ClusterService clusterService = internalCluster().clusterService(masterNode1);
+        ClusterService clusterService = internalCluster().clusterService(clusterManagerNode1);
         CountDownLatch disruptionStarted = new CountDownLatch(1);
         clusterService.addListener(new ClusterStateListener() {
             @Override
@@ -124,7 +124,7 @@ public void clusterChanged(ClusterChangedEvent event) {
         final String snapshot = "test-snap";
 
         logger.info("--> starting snapshot");
-        ActionFuture<CreateSnapshotResponse> future = client(masterNode1).admin()
+        ActionFuture<CreateSnapshotResponse> future = client(clusterManagerNode1).admin()
             .cluster()
             .prepareCreateSnapshot("test-repo", snapshot)
             .setWaitForCompletion(true)
@@ -147,7 +147,7 @@ public void clusterChanged(ClusterChangedEvent event) {
 
         logger.info("--> stopping disrupting");
         networkDisruption.stopDisrupting();
-        ensureStableCluster(4, masterNode1);
+        ensureStableCluster(4, clusterManagerNode1);
         logger.info("--> done");
 
         try {
@@ -158,7 +158,7 @@ public void clusterChanged(ClusterChangedEvent event) {
             assertNotNull(sne);
             assertThat(
                 sne.getMessage(),
-                either(endsWith(" Failed to update cluster state during snapshot finalization")).or(endsWith(" no longer master"))
+                either(endsWith(" Failed to update cluster state during snapshot finalization")).or(endsWith(" no longer cluster-manager"))
             );
             assertThat(sne.getSnapshotName(), is(snapshot));
         }
@@ -168,7 +168,7 @@ public void clusterChanged(ClusterChangedEvent event) {
 
     public void testDisruptionAfterShardFinalization() throws Exception {
         final String idxName = "test";
-        internalCluster().startMasterOnlyNodes(1);
+        internalCluster().startClusterManagerOnlyNodes(1);
         internalCluster().startDataOnlyNode();
         ensureStableCluster(2);
         createIndex(idxName);
@@ -177,13 +177,13 @@ public void testDisruptionAfterShardFinalization() throws Exception {
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
 
-        final String masterNode = internalCluster().getMasterName();
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
 
         blockAllDataNodes(repoName);
 
         final String snapshot = "test-snap";
         logger.info("--> starting snapshot");
-        ActionFuture<CreateSnapshotResponse> future = client(masterNode).admin()
+        ActionFuture<CreateSnapshotResponse> future = client(clusterManagerNode).admin()
             .cluster()
             .prepareCreateSnapshot(repoName, snapshot)
             .setWaitForCompletion(true)
@@ -191,7 +191,7 @@ public void testDisruptionAfterShardFinalization() throws Exception {
 
         waitForBlockOnAnyDataNode(repoName, TimeValue.timeValueSeconds(10L));
 
-        NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
         networkDisruption.startDisrupting();
 
@@ -203,7 +203,7 @@ public void testDisruptionAfterShardFinalization() throws Exception {
         networkDisruption.stopDisrupting();
         unblockAllDataNodes(repoName);
 
-        ensureStableCluster(2, masterNode);
+        ensureStableCluster(2, clusterManagerNode);
         logger.info("--> done");
 
         logger.info("--> recreate the index with potentially different shard counts");
@@ -212,18 +212,18 @@ public void testDisruptionAfterShardFinalization() throws Exception {
         index(idxName, "type", JsonXContent.contentBuilder().startObject().field("foo", "bar").endObject());
 
         logger.info("--> run a snapshot that fails to finalize but succeeds on the data node");
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
-        final ActionFuture<CreateSnapshotResponse> snapshotFuture = client(masterNode).admin()
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
+        final ActionFuture<CreateSnapshotResponse> snapshotFuture = client(clusterManagerNode).admin()
             .cluster()
             .prepareCreateSnapshot(repoName, "snapshot-2")
             .setWaitForCompletion(true)
             .execute();
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(10L));
-        unblockNode(repoName, masterNode);
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(10L));
+        unblockNode(repoName, clusterManagerNode);
         assertFutureThrows(snapshotFuture, SnapshotException.class);
 
         logger.info("--> create a snapshot expected to be successful");
-        final CreateSnapshotResponse successfulSnapshot = client(masterNode).admin()
+        final CreateSnapshotResponse successfulSnapshot = client(clusterManagerNode).admin()
             .cluster()
             .prepareCreateSnapshot(repoName, "snapshot-2")
             .setWaitForCompletion(true)
@@ -235,8 +235,8 @@ public void testDisruptionAfterShardFinalization() throws Exception {
         assertAcked(client().admin().cluster().prepareDeleteSnapshot(repoName, "snapshot-2").get());
     }
 
-    public void testMasterFailOverDuringShardSnapshots() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testClusterManagerFailOverDuringShardSnapshots() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         ensureStableCluster(4);
         final String repoName = "test-repo";
@@ -248,8 +248,8 @@ public void testMasterFailOverDuringShardSnapshots() throws Exception {
 
         blockDataNode(repoName, dataNode);
 
-        logger.info("--> create snapshot via master node client");
-        final ActionFuture<CreateSnapshotResponse> snapshotResponse = internalCluster().masterClient()
+        logger.info("--> create snapshot via cluster-manager node client");
+        final ActionFuture<CreateSnapshotResponse> snapshotResponse = internalCluster().clusterManagerClient()
             .admin()
             .cluster()
             .prepareCreateSnapshot(repoName, "test-snap")
@@ -258,7 +258,7 @@ public void testMasterFailOverDuringShardSnapshots() throws Exception {
 
         waitForBlock(dataNode, repoName, TimeValue.timeValueSeconds(30L));
 
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
         networkDisruption.startDisrupting();
         ensureStableCluster(3, dataNode);
@@ -267,12 +267,12 @@ public void testMasterFailOverDuringShardSnapshots() throws Exception {
         networkDisruption.stopDisrupting();
         awaitNoMoreRunningOperations(dataNode);
 
-        logger.info("--> make sure isolated master responds to snapshot request");
+        logger.info("--> make sure isolated cluster-manager responds to snapshot request");
         final SnapshotException sne = expectThrows(
             SnapshotException.class,
             () -> snapshotResponse.actionGet(TimeValue.timeValueSeconds(30L))
         );
-        assertThat(sne.getMessage(), endsWith("no longer master"));
+        assertThat(sne.getMessage(), endsWith("no longer cluster-manager"));
     }
 
     private void assertSnapshotExists(String repository, String snapshot) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/StableClusterManagerDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/StableClusterManagerDisruptionIT.java
new file mode 100644
index 0000000000000..c12718704e194
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/StableClusterManagerDisruptionIT.java
@@ -0,0 +1,304 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery;
+
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.coordination.Coordinator;
+import org.opensearch.cluster.coordination.FollowersChecker;
+import org.opensearch.cluster.coordination.LeaderChecker;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.Strings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.LongGCDisruption;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.disruption.NetworkDisruption.NetworkLinkDisruptionType;
+import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
+import org.opensearch.test.disruption.SingleNodeDisruption;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.singleton;
+import static org.hamcrest.Matchers.equalTo;
+
+/**
+ * Tests relating to the loss of the cluster-manager, but which work with the default fault detection settings which are rather lenient and will
+ * not detect a cluster-manager failure too quickly.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class StableClusterManagerDisruptionIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Collections.singletonList(MockTransportService.TestPlugin.class);
+    }
+
+    /**
+     * Test that no split brain occurs under partial network partition. See https://github.com/elastic/elasticsearch/issues/2488
+     */
+    public void testFailWithMinimumClusterManagerNodesConfigured() throws Exception {
+        List<String> nodes = internalCluster().startNodes(3);
+        ensureStableCluster(3);
+
+        // Figure out what is the elected cluster-manager node
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        logger.info("---> legit elected cluster-manager node={}", clusterManagerNode);
+
+        // Pick a node that isn't the elected cluster-manager.
+        Set<String> nonClusterManagers = new HashSet<>(nodes);
+        nonClusterManagers.remove(clusterManagerNode);
+        final String unluckyNode = randomFrom(nonClusterManagers.toArray(Strings.EMPTY_ARRAY));
+
+        // Simulate a network issue between the unlucky node and elected cluster-manager node in both directions.
+
+        NetworkDisruption networkDisconnect = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(clusterManagerNode, unluckyNode),
+            NetworkDisruption.DISCONNECT
+        );
+        setDisruptionScheme(networkDisconnect);
+        networkDisconnect.startDisrupting();
+
+        // Wait until elected cluster-manager has removed that the unlucky node...
+        ensureStableCluster(2, clusterManagerNode);
+
+        // The unlucky node must report *no* cluster-manager node, since it can't connect to cluster-manager and in fact it should
+        // continuously ping until network failures have been resolved. However
+        // It may a take a bit before the node detects it has been cut off from the elected cluster-manager
+        ensureNoMaster(unluckyNode);
+
+        networkDisconnect.stopDisrupting();
+
+        // Wait until the cluster-manager node sees all 3 nodes again.
+        ensureStableCluster(3);
+
+        // The elected cluster-manager shouldn't have changed, since the unlucky node never could have elected itself as cluster-manager
+        assertThat(internalCluster().getClusterManagerName(), equalTo(clusterManagerNode));
+    }
+
+    private void ensureNoMaster(String node) throws Exception {
+        assertBusy(
+            () -> assertNull(
+                client(node).admin().cluster().state(new ClusterStateRequest().local(true)).get().getState().nodes().getClusterManagerNode()
+            )
+        );
+    }
+
+    /**
+     * Verify that nodes fault detection detects a disconnected node after cluster-manager reelection
+     */
+    public void testFollowerCheckerDetectsDisconnectedNodeAfterClusterManagerReelection() throws Exception {
+        testFollowerCheckerAfterClusterManagerReelection(NetworkDisruption.DISCONNECT, Settings.EMPTY);
+    }
+
+    /**
+     * Verify that nodes fault detection detects an unresponsive node after cluster-manager reelection
+     */
+    public void testFollowerCheckerDetectsUnresponsiveNodeAfterClusterManagerReelection() throws Exception {
+        testFollowerCheckerAfterClusterManagerReelection(
+            NetworkDisruption.UNRESPONSIVE,
+            Settings.builder()
+                .put(LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
+                .put(LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING.getKey(), "4")
+                .put(FollowersChecker.FOLLOWER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
+                .put(FollowersChecker.FOLLOWER_CHECK_RETRY_COUNT_SETTING.getKey(), 1)
+                .build()
+        );
+    }
+
+    private void testFollowerCheckerAfterClusterManagerReelection(NetworkLinkDisruptionType networkLinkDisruptionType, Settings settings)
+        throws Exception {
+        internalCluster().startNodes(4, settings);
+        ensureStableCluster(4);
+
+        logger.info("--> stopping current cluster-manager");
+        internalCluster().stopCurrentClusterManagerNode();
+
+        ensureStableCluster(3);
+
+        final String clusterManager = internalCluster().getClusterManagerName();
+        final List<String> nonClusterManagers = Arrays.stream(internalCluster().getNodeNames())
+            .filter(n -> clusterManager.equals(n) == false)
+            .collect(Collectors.toList());
+        final String isolatedNode = randomFrom(nonClusterManagers);
+        final String otherNode = nonClusterManagers.get(nonClusterManagers.get(0).equals(isolatedNode) ? 1 : 0);
+
+        logger.info("--> isolating [{}]", isolatedNode);
+
+        final NetworkDisruption networkDisruption = new NetworkDisruption(
+            new TwoPartitions(singleton(isolatedNode), Sets.newHashSet(clusterManager, otherNode)),
+            networkLinkDisruptionType
+        );
+        setDisruptionScheme(networkDisruption);
+        networkDisruption.startDisrupting();
+
+        logger.info("--> waiting for cluster-manager to remove it");
+        ensureStableCluster(2, clusterManager);
+        ensureNoMaster(isolatedNode);
+
+        networkDisruption.stopDisrupting();
+        ensureStableCluster(3);
+    }
+
+    /**
+     * Tests that emulates a frozen elected cluster-manager node that unfreezes and pushes its cluster state to other nodes that already are
+     * following another elected cluster-manager node. These nodes should reject this cluster state and prevent them from following the stale cluster-manager.
+     */
+    public void testStaleClusterManagerNotHijackingMajority() throws Exception {
+        final List<String> nodes = internalCluster().startNodes(
+            3,
+            Settings.builder()
+                .put(LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
+                .put(Coordinator.PUBLISH_TIMEOUT_SETTING.getKey(), "1s")
+                .build()
+        );
+        ensureStableCluster(3);
+
+        // Save the current cluster-manager node as old cluster-manager node, because that node will get frozen
+        final String oldClusterManagerNode = internalCluster().getClusterManagerName();
+
+        // Simulating a painful gc by suspending all threads for a long time on the current elected cluster-manager node.
+        SingleNodeDisruption clusterManagerNodeDisruption = new LongGCDisruption(random(), oldClusterManagerNode);
+
+        // Save the majority side
+        final List<String> majoritySide = new ArrayList<>(nodes);
+        majoritySide.remove(oldClusterManagerNode);
+
+        // Keeps track of the previous and current cluster-manager when a cluster-manager node transition took place on each node on the
+        // majority side:
+        final Map<String, List<Tuple<String, String>>> clusterManagers = Collections.synchronizedMap(new HashMap<>());
+        for (final String node : majoritySide) {
+            clusterManagers.put(node, new ArrayList<>());
+            internalCluster().getInstance(ClusterService.class, node).addListener(event -> {
+                DiscoveryNode previousClusterManager = event.previousState().nodes().getClusterManagerNode();
+                DiscoveryNode currentClusterManager = event.state().nodes().getClusterManagerNode();
+                if (!Objects.equals(previousClusterManager, currentClusterManager)) {
+                    logger.info(
+                        "--> node {} received new cluster state: {} \n and had previous cluster state: {}",
+                        node,
+                        event.state(),
+                        event.previousState()
+                    );
+                    String previousClusterManagerNodeName = previousClusterManager != null ? previousClusterManager.getName() : null;
+                    String currentClusterManagerNodeName = currentClusterManager != null ? currentClusterManager.getName() : null;
+                    clusterManagers.get(node).add(new Tuple<>(previousClusterManagerNodeName, currentClusterManagerNodeName));
+                }
+            });
+        }
+
+        final CountDownLatch oldClusterManagerNodeSteppedDown = new CountDownLatch(1);
+        internalCluster().getInstance(ClusterService.class, oldClusterManagerNode).addListener(event -> {
+            if (event.state().nodes().getClusterManagerNodeId() == null) {
+                oldClusterManagerNodeSteppedDown.countDown();
+            }
+        });
+
+        internalCluster().setDisruptionScheme(clusterManagerNodeDisruption);
+        logger.info("--> freezing node [{}]", oldClusterManagerNode);
+        clusterManagerNodeDisruption.startDisrupting();
+
+        // Wait for majority side to elect a new cluster-manager
+        assertBusy(() -> {
+            for (final Map.Entry<String, List<Tuple<String, String>>> entry : clusterManagers.entrySet()) {
+                final List<Tuple<String, String>> transitions = entry.getValue();
+                assertTrue(entry.getKey() + ": " + transitions, transitions.stream().anyMatch(transition -> transition.v2() != null));
+            }
+        });
+
+        // The old cluster-manager node is frozen, but here we submit a cluster state update task that doesn't get executed, but will be
+        // queued and
+        // once the old cluster-manager node un-freezes it gets executed. The old cluster-manager node will send this update + the cluster
+        // state where it is
+        // flagged as cluster-manager to the other nodes that follow the new cluster-manager. These nodes should ignore this update.
+        internalCluster().getInstance(ClusterService.class, oldClusterManagerNode)
+            .submitStateUpdateTask("sneaky-update", new ClusterStateUpdateTask(Priority.IMMEDIATE) {
+                @Override
+                public ClusterState execute(ClusterState currentState) {
+                    return ClusterState.builder(currentState).build();
+                }
+
+                @Override
+                public void onFailure(String source, Exception e) {
+                    logger.warn(() -> new ParameterizedMessage("failure [{}]", source), e);
+                }
+            });
+
+        // Save the new elected cluster-manager node
+        final String newClusterManagerNode = internalCluster().getClusterManagerName(majoritySide.get(0));
+        logger.info("--> new detected cluster-manager node [{}]", newClusterManagerNode);
+
+        // Stop disruption
+        logger.info("--> unfreezing node [{}]", oldClusterManagerNode);
+        clusterManagerNodeDisruption.stopDisrupting();
+
+        oldClusterManagerNodeSteppedDown.await(30, TimeUnit.SECONDS);
+        logger.info("--> [{}] stepped down as cluster-manager", oldClusterManagerNode);
+        ensureStableCluster(3);
+
+        assertThat(clusterManagers.size(), equalTo(2));
+        for (Map.Entry<String, List<Tuple<String, String>>> entry : clusterManagers.entrySet()) {
+            String nodeName = entry.getKey();
+            List<Tuple<String, String>> transitions = entry.getValue();
+            assertTrue(
+                "["
+                    + nodeName
+                    + "] should not apply state from old cluster-manager ["
+                    + oldClusterManagerNode
+                    + "] but it did: "
+                    + transitions,
+                transitions.stream().noneMatch(t -> oldClusterManagerNode.equals(t.v2()))
+            );
+        }
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/StableMasterDisruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/StableMasterDisruptionIT.java
deleted file mode 100644
index 77553ba713540..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/StableMasterDisruptionIT.java
+++ /dev/null
@@ -1,296 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.discovery;
-
-import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.coordination.Coordinator;
-import org.opensearch.cluster.coordination.FollowersChecker;
-import org.opensearch.cluster.coordination.LeaderChecker;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.set.Sets;
-import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.disruption.LongGCDisruption;
-import org.opensearch.test.disruption.NetworkDisruption;
-import org.opensearch.test.disruption.NetworkDisruption.NetworkLinkDisruptionType;
-import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
-import org.opensearch.test.disruption.SingleNodeDisruption;
-import org.opensearch.test.transport.MockTransportService;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
-import java.util.stream.Collectors;
-
-import static java.util.Collections.singleton;
-import static org.hamcrest.Matchers.equalTo;
-
-/**
- * Tests relating to the loss of the master, but which work with the default fault detection settings which are rather lenient and will
- * not detect a master failure too quickly.
- */
-@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
-public class StableMasterDisruptionIT extends OpenSearchIntegTestCase {
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Collections.singletonList(MockTransportService.TestPlugin.class);
-    }
-
-    /**
-     * Test that no split brain occurs under partial network partition. See https://github.com/elastic/elasticsearch/issues/2488
-     */
-    public void testFailWithMinimumMasterNodesConfigured() throws Exception {
-        List<String> nodes = internalCluster().startNodes(3);
-        ensureStableCluster(3);
-
-        // Figure out what is the elected master node
-        final String masterNode = internalCluster().getMasterName();
-        logger.info("---> legit elected master node={}", masterNode);
-
-        // Pick a node that isn't the elected master.
-        Set<String> nonMasters = new HashSet<>(nodes);
-        nonMasters.remove(masterNode);
-        final String unluckyNode = randomFrom(nonMasters.toArray(Strings.EMPTY_ARRAY));
-
-        // Simulate a network issue between the unlucky node and elected master node in both directions.
-
-        NetworkDisruption networkDisconnect = new NetworkDisruption(
-            new NetworkDisruption.TwoPartitions(masterNode, unluckyNode),
-            NetworkDisruption.DISCONNECT
-        );
-        setDisruptionScheme(networkDisconnect);
-        networkDisconnect.startDisrupting();
-
-        // Wait until elected master has removed that the unlucky node...
-        ensureStableCluster(2, masterNode);
-
-        // The unlucky node must report *no* master node, since it can't connect to master and in fact it should
-        // continuously ping until network failures have been resolved. However
-        // It may a take a bit before the node detects it has been cut off from the elected master
-        ensureNoMaster(unluckyNode);
-
-        networkDisconnect.stopDisrupting();
-
-        // Wait until the master node sees all 3 nodes again.
-        ensureStableCluster(3);
-
-        // The elected master shouldn't have changed, since the unlucky node never could have elected itself as master
-        assertThat(internalCluster().getMasterName(), equalTo(masterNode));
-    }
-
-    private void ensureNoMaster(String node) throws Exception {
-        assertBusy(
-            () -> assertNull(
-                client(node).admin().cluster().state(new ClusterStateRequest().local(true)).get().getState().nodes().getMasterNode()
-            )
-        );
-    }
-
-    /**
-     * Verify that nodes fault detection detects a disconnected node after master reelection
-     */
-    public void testFollowerCheckerDetectsDisconnectedNodeAfterMasterReelection() throws Exception {
-        testFollowerCheckerAfterMasterReelection(NetworkDisruption.DISCONNECT, Settings.EMPTY);
-    }
-
-    /**
-     * Verify that nodes fault detection detects an unresponsive node after master reelection
-     */
-    public void testFollowerCheckerDetectsUnresponsiveNodeAfterMasterReelection() throws Exception {
-        testFollowerCheckerAfterMasterReelection(
-            NetworkDisruption.UNRESPONSIVE,
-            Settings.builder()
-                .put(LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
-                .put(LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING.getKey(), "4")
-                .put(FollowersChecker.FOLLOWER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
-                .put(FollowersChecker.FOLLOWER_CHECK_RETRY_COUNT_SETTING.getKey(), 1)
-                .build()
-        );
-    }
-
-    private void testFollowerCheckerAfterMasterReelection(NetworkLinkDisruptionType networkLinkDisruptionType, Settings settings)
-        throws Exception {
-        internalCluster().startNodes(4, settings);
-        ensureStableCluster(4);
-
-        logger.info("--> stopping current master");
-        internalCluster().stopCurrentMasterNode();
-
-        ensureStableCluster(3);
-
-        final String master = internalCluster().getMasterName();
-        final List<String> nonMasters = Arrays.stream(internalCluster().getNodeNames())
-            .filter(n -> master.equals(n) == false)
-            .collect(Collectors.toList());
-        final String isolatedNode = randomFrom(nonMasters);
-        final String otherNode = nonMasters.get(nonMasters.get(0).equals(isolatedNode) ? 1 : 0);
-
-        logger.info("--> isolating [{}]", isolatedNode);
-
-        final NetworkDisruption networkDisruption = new NetworkDisruption(
-            new TwoPartitions(singleton(isolatedNode), Sets.newHashSet(master, otherNode)),
-            networkLinkDisruptionType
-        );
-        setDisruptionScheme(networkDisruption);
-        networkDisruption.startDisrupting();
-
-        logger.info("--> waiting for master to remove it");
-        ensureStableCluster(2, master);
-        ensureNoMaster(isolatedNode);
-
-        networkDisruption.stopDisrupting();
-        ensureStableCluster(3);
-    }
-
-    /**
-     * Tests that emulates a frozen elected master node that unfreezes and pushes its cluster state to other nodes that already are
-     * following another elected master node. These nodes should reject this cluster state and prevent them from following the stale master.
-     */
-    public void testStaleMasterNotHijackingMajority() throws Exception {
-        final List<String> nodes = internalCluster().startNodes(
-            3,
-            Settings.builder()
-                .put(LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
-                .put(Coordinator.PUBLISH_TIMEOUT_SETTING.getKey(), "1s")
-                .build()
-        );
-        ensureStableCluster(3);
-
-        // Save the current master node as old master node, because that node will get frozen
-        final String oldMasterNode = internalCluster().getMasterName();
-
-        // Simulating a painful gc by suspending all threads for a long time on the current elected master node.
-        SingleNodeDisruption masterNodeDisruption = new LongGCDisruption(random(), oldMasterNode);
-
-        // Save the majority side
-        final List<String> majoritySide = new ArrayList<>(nodes);
-        majoritySide.remove(oldMasterNode);
-
-        // Keeps track of the previous and current master when a master node transition took place on each node on the majority side:
-        final Map<String, List<Tuple<String, String>>> masters = Collections.synchronizedMap(new HashMap<>());
-        for (final String node : majoritySide) {
-            masters.put(node, new ArrayList<>());
-            internalCluster().getInstance(ClusterService.class, node).addListener(event -> {
-                DiscoveryNode previousMaster = event.previousState().nodes().getMasterNode();
-                DiscoveryNode currentMaster = event.state().nodes().getMasterNode();
-                if (!Objects.equals(previousMaster, currentMaster)) {
-                    logger.info(
-                        "--> node {} received new cluster state: {} \n and had previous cluster state: {}",
-                        node,
-                        event.state(),
-                        event.previousState()
-                    );
-                    String previousMasterNodeName = previousMaster != null ? previousMaster.getName() : null;
-                    String currentMasterNodeName = currentMaster != null ? currentMaster.getName() : null;
-                    masters.get(node).add(new Tuple<>(previousMasterNodeName, currentMasterNodeName));
-                }
-            });
-        }
-
-        final CountDownLatch oldMasterNodeSteppedDown = new CountDownLatch(1);
-        internalCluster().getInstance(ClusterService.class, oldMasterNode).addListener(event -> {
-            if (event.state().nodes().getMasterNodeId() == null) {
-                oldMasterNodeSteppedDown.countDown();
-            }
-        });
-
-        internalCluster().setDisruptionScheme(masterNodeDisruption);
-        logger.info("--> freezing node [{}]", oldMasterNode);
-        masterNodeDisruption.startDisrupting();
-
-        // Wait for majority side to elect a new master
-        assertBusy(() -> {
-            for (final Map.Entry<String, List<Tuple<String, String>>> entry : masters.entrySet()) {
-                final List<Tuple<String, String>> transitions = entry.getValue();
-                assertTrue(entry.getKey() + ": " + transitions, transitions.stream().anyMatch(transition -> transition.v2() != null));
-            }
-        });
-
-        // The old master node is frozen, but here we submit a cluster state update task that doesn't get executed, but will be queued and
-        // once the old master node un-freezes it gets executed. The old master node will send this update + the cluster state where it is
-        // flagged as master to the other nodes that follow the new master. These nodes should ignore this update.
-        internalCluster().getInstance(ClusterService.class, oldMasterNode)
-            .submitStateUpdateTask("sneaky-update", new ClusterStateUpdateTask(Priority.IMMEDIATE) {
-                @Override
-                public ClusterState execute(ClusterState currentState) {
-                    return ClusterState.builder(currentState).build();
-                }
-
-                @Override
-                public void onFailure(String source, Exception e) {
-                    logger.warn(() -> new ParameterizedMessage("failure [{}]", source), e);
-                }
-            });
-
-        // Save the new elected master node
-        final String newMasterNode = internalCluster().getMasterName(majoritySide.get(0));
-        logger.info("--> new detected master node [{}]", newMasterNode);
-
-        // Stop disruption
-        logger.info("--> unfreezing node [{}]", oldMasterNode);
-        masterNodeDisruption.stopDisrupting();
-
-        oldMasterNodeSteppedDown.await(30, TimeUnit.SECONDS);
-        logger.info("--> [{}] stepped down as master", oldMasterNode);
-        ensureStableCluster(3);
-
-        assertThat(masters.size(), equalTo(2));
-        for (Map.Entry<String, List<Tuple<String, String>>> entry : masters.entrySet()) {
-            String nodeName = entry.getKey();
-            List<Tuple<String, String>> transitions = entry.getValue();
-            assertTrue(
-                "[" + nodeName + "] should not apply state from old master [" + oldMasterNode + "] but it did: " + transitions,
-                transitions.stream().noneMatch(t -> oldMasterNode.equals(t.v2()))
-            );
-        }
-    }
-
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/discovery/single/SingleNodeDiscoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/discovery/single/SingleNodeDiscoveryIT.java
index 13aea01772424..1f6c8eac6c391 100644
--- a/server/src/internalClusterTest/java/org/opensearch/discovery/single/SingleNodeDiscoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/discovery/single/SingleNodeDiscoveryIT.java
@@ -41,11 +41,11 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.node.Node.DiscoverySettings;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockHttpTransport;
 import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.NodeConfigurationSource;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.transport.RemoteTransportException;
 import org.opensearch.transport.TransportService;
 
@@ -76,6 +76,7 @@ public void testSingleNodesDoNotDiscoverEachOther() throws IOException, Interrup
             @Override
             public Settings nodeSettings(int nodeOrdinal) {
                 return Settings.builder()
+                    .put(featureFlagSettings())
                     .put("discovery.type", "single-node")
                     .put("transport.type", getTestTransportType())
                     /*
@@ -112,7 +113,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
             final ClusterState second = other.getInstance(ClusterService.class).state();
             assertThat(first.nodes().getSize(), equalTo(1));
             assertThat(second.nodes().getSize(), equalTo(1));
-            assertThat(first.nodes().getMasterNodeId(), not(equalTo(second.nodes().getMasterNodeId())));
+            assertThat(first.nodes().getClusterManagerNodeId(), not(equalTo(second.nodes().getClusterManagerNodeId())));
             assertThat(first.metadata().clusterUUID(), not(equalTo(second.metadata().clusterUUID())));
         }
     }
@@ -142,6 +143,7 @@ public boolean innerMatch(final LogEvent event) {
                 @Override
                 public Settings nodeSettings(int nodeOrdinal) {
                     return Settings.builder()
+                        .put(featureFlagSettings())
                         .put("discovery.type", "zen")
                         .put("transport.type", getTestTransportType())
                         .put(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey(), "0s")
diff --git a/server/src/internalClusterTest/java/org/opensearch/document/DocumentActionsIT.java b/server/src/internalClusterTest/java/org/opensearch/document/DocumentActionsIT.java
index 1e40cc14bbb36..0336ccf3f4647 100644
--- a/server/src/internalClusterTest/java/org/opensearch/document/DocumentActionsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/document/DocumentActionsIT.java
@@ -43,11 +43,9 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
 import org.opensearch.cluster.health.ClusterHealthStatus;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.mapper.MapperService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
@@ -58,9 +56,8 @@
 import static org.opensearch.client.Requests.getRequest;
 import static org.opensearch.client.Requests.indexRequest;
 import static org.opensearch.client.Requests.refreshRequest;
-import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
 
@@ -118,10 +115,10 @@ public void testIndexActions() throws Exception {
         for (int i = 0; i < 5; i++) {
             getResult = client().prepareGet("test", "1").execute().actionGet();
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("1", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("1", "test").toString()));
             assertThat("cycle(map) #" + i, (String) getResult.getSourceAsMap().get("name"), equalTo("test"));
             getResult = client().get(getRequest("test").id("1")).actionGet();
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("1", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("1", "test").toString()));
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
         }
 
@@ -169,10 +166,10 @@ public void testIndexActions() throws Exception {
         for (int i = 0; i < 5; i++) {
             getResult = client().get(getRequest("test").id("1")).actionGet();
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("1", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("1", "test").toString()));
             getResult = client().get(getRequest("test").id("2")).actionGet();
             String ste1 = getResult.getSourceAsString();
-            String ste2 = Strings.toString(source("2", "test2"));
+            String ste2 = source("2", "test2").toString();
             assertThat("cycle #" + i, ste1, equalTo(ste2));
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
         }
@@ -181,11 +178,7 @@ public void testIndexActions() throws Exception {
         // check count
         for (int i = 0; i < 5; i++) {
             // test successful
-            SearchResponse countResponse = client().prepareSearch("test")
-                .setSize(0)
-                .setQuery(termQuery("_type", MapperService.SINGLE_MAPPING_NAME))
-                .execute()
-                .actionGet();
+            SearchResponse countResponse = client().prepareSearch("test").setSize(0).setQuery(matchAllQuery()).execute().actionGet();
             assertNoFailures(countResponse);
             assertThat(countResponse.getHits().getTotalHits().value, equalTo(2L));
             assertThat(countResponse.getSuccessfulShards(), equalTo(numShards.numPrimaries));
@@ -216,7 +209,7 @@ public void testBulk() throws Exception {
             .add(client().prepareIndex().setIndex("test").setSource(source("3", "test")))
             .add(client().prepareIndex().setIndex("test").setCreate(true).setSource(source("4", "test")))
             .add(client().prepareDelete().setIndex("test").setId("1"))
-            .add(client().prepareIndex().setIndex("test").setSource("{ xxx }", XContentType.JSON)) // failure
+            .add(client().prepareIndex().setIndex("test").setSource("{ xxx }", MediaTypeRegistry.JSON)) // failure
             .execute()
             .actionGet();
 
@@ -263,15 +256,15 @@ public void testBulk() throws Exception {
             assertThat("cycle #" + i, getResult.isExists(), equalTo(false));
 
             getResult = client().get(getRequest("test").id("2")).actionGet();
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("2", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("2", "test").toString()));
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
 
             getResult = client().get(getRequest("test").id(generatedId3)).actionGet();
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("3", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("3", "test").toString()));
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
 
             getResult = client().get(getRequest("test").id(generatedId4)).actionGet();
-            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(Strings.toString(source("4", "test"))));
+            assertThat("cycle #" + i, getResult.getSourceAsString(), equalTo(source("4", "test").toString()));
             assertThat(getResult.getIndex(), equalTo(getConcreteIndexName()));
         }
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/document/ShardInfoIT.java b/server/src/internalClusterTest/java/org/opensearch/document/ShardInfoIT.java
index 5f217548794db..77c0c6edef623 100644
--- a/server/src/internalClusterTest/java/org/opensearch/document/ShardInfoIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/document/ShardInfoIT.java
@@ -44,11 +44,10 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.not;
@@ -60,7 +59,7 @@ public class ShardInfoIT extends OpenSearchIntegTestCase {
 
     public void testIndexAndDelete() throws Exception {
         prepareIndex(1);
-        IndexResponse indexResponse = client().prepareIndex("idx").setSource("{}", XContentType.JSON).get();
+        IndexResponse indexResponse = client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON).get();
         assertShardInfo(indexResponse);
         DeleteResponse deleteResponse = client().prepareDelete("idx", indexResponse.getId()).get();
         assertShardInfo(deleteResponse);
@@ -68,7 +67,7 @@ public void testIndexAndDelete() throws Exception {
 
     public void testUpdate() throws Exception {
         prepareIndex(1);
-        UpdateResponse updateResponse = client().prepareUpdate("idx", "1").setDoc("{}", XContentType.JSON).setDocAsUpsert(true).get();
+        UpdateResponse updateResponse = client().prepareUpdate("idx", "1").setDoc("{}", MediaTypeRegistry.JSON).setDocAsUpsert(true).get();
         assertShardInfo(updateResponse);
     }
 
@@ -76,7 +75,7 @@ public void testBulkWithIndexAndDeleteItems() throws Exception {
         prepareIndex(1);
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
         for (int i = 0; i < 10; i++) {
-            bulkRequestBuilder.add(client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+            bulkRequestBuilder.add(client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
         }
 
         BulkResponse bulkResponse = bulkRequestBuilder.get();
@@ -98,7 +97,9 @@ public void testBulkWithUpdateItems() throws Exception {
         prepareIndex(1);
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
         for (int i = 0; i < 10; i++) {
-            bulkRequestBuilder.add(client().prepareUpdate("idx", Integer.toString(i)).setDoc("{}", XContentType.JSON).setDocAsUpsert(true));
+            bulkRequestBuilder.add(
+                client().prepareUpdate("idx", Integer.toString(i)).setDoc("{}", MediaTypeRegistry.JSON).setDocAsUpsert(true)
+            );
         }
 
         BulkResponse bulkResponse = bulkRequestBuilder.get();
diff --git a/server/src/internalClusterTest/java/org/opensearch/env/NodeEnvironmentIT.java b/server/src/internalClusterTest/java/org/opensearch/env/NodeEnvironmentIT.java
index 83c103bd82738..43f1608210668 100644
--- a/server/src/internalClusterTest/java/org/opensearch/env/NodeEnvironmentIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/env/NodeEnvironmentIT.java
@@ -39,9 +39,9 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.gateway.PersistedClusterStateService;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.NodeRoles;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.nio.file.Path;
@@ -79,10 +79,10 @@ public void testStartFailureOnDataForNonDataNode() throws Exception {
             );
         }
 
-        logger.info("--> restarting the node without the data and master roles");
+        logger.info("--> restarting the node without the data and cluster-manager roles");
         IllegalStateException ex = expectThrows(
             IllegalStateException.class,
-            "node not having the data and master roles while having existing index metadata must fail",
+            "node not having the data and cluster-manager roles while having existing index metadata must fail",
             () -> internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
                 @Override
                 public Settings onNodeStopped(String nodeName) {
@@ -100,7 +100,7 @@ public Settings onNodeStopped(String nodeName) {
             assertThat(ex.getMessage(), startsWith("node does not have the data role but has shard data"));
         }
 
-        logger.info("--> start the node again with data and master roles");
+        logger.info("--> start the node again with data and cluster-manager roles");
         internalCluster().startNode(dataPathSettings);
 
         logger.info("--> indexing a simple document");
diff --git a/server/src/internalClusterTest/java/org/opensearch/env/NodeRepurposeCommandIT.java b/server/src/internalClusterTest/java/org/opensearch/env/NodeRepurposeCommandIT.java
index 2547333490f23..420a24d6d3aae 100644
--- a/server/src/internalClusterTest/java/org/opensearch/env/NodeRepurposeCommandIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/env/NodeRepurposeCommandIT.java
@@ -37,9 +37,8 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.NodeRoles;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
 
 import java.util.Arrays;
@@ -56,7 +55,7 @@ public void testRepurpose() throws Exception {
         final String indexName = "test-repurpose";
 
         logger.info("--> starting two nodes");
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode(
             Settings.builder().put(IndicesService.WRITE_DANGLING_INDICES_INFO_SETTING.getKey(), false).build()
         );
@@ -71,20 +70,20 @@ public void testRepurpose() throws Exception {
 
         assertTrue(client().prepareGet(indexName, "1").get().isExists());
 
-        final Settings masterNodeDataPathSettings = internalCluster().dataPathSettings(masterNode);
+        final Settings clusterManagerNodeDataPathSettings = internalCluster().dataPathSettings(clusterManagerNode);
         final Settings dataNodeDataPathSettings = internalCluster().dataPathSettings(dataNode);
 
-        final Settings noMasterNoDataSettings = NodeRoles.removeRoles(
+        final Settings noClusterManagerNoDataSettings = NodeRoles.removeRoles(
             Collections.unmodifiableSet(new HashSet<>(Arrays.asList(DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.MASTER_ROLE)))
         );
 
-        final Settings noMasterNoDataSettingsForMasterNode = Settings.builder()
-            .put(noMasterNoDataSettings)
-            .put(masterNodeDataPathSettings)
+        final Settings noClusterManagerNoDataSettingsForClusterManagerNode = Settings.builder()
+            .put(noClusterManagerNoDataSettings)
+            .put(clusterManagerNodeDataPathSettings)
             .build();
 
-        final Settings noMasterNoDataSettingsForDataNode = Settings.builder()
-            .put(noMasterNoDataSettings)
+        final Settings noClusterManagerNoDataSettingsForDataNode = Settings.builder()
+            .put(noClusterManagerNoDataSettings)
             .put(dataNodeDataPathSettings)
             .build();
 
@@ -99,11 +98,11 @@ public void testRepurpose() throws Exception {
         );
 
         logger.info("--> Repurposing node 1");
-        executeRepurposeCommand(noMasterNoDataSettingsForDataNode, 1, 1);
+        executeRepurposeCommand(noClusterManagerNoDataSettingsForDataNode, 1, 1);
 
         OpenSearchException lockedException = expectThrows(
             OpenSearchException.class,
-            () -> executeRepurposeCommand(noMasterNoDataSettingsForMasterNode, 1, 1)
+            () -> executeRepurposeCommand(noClusterManagerNoDataSettingsForClusterManagerNode, 1, 1)
         );
 
         assertThat(lockedException.getMessage(), containsString(NodeRepurposeCommand.FAILED_TO_OBTAIN_NODE_LOCK_MSG));
@@ -119,11 +118,11 @@ public void testRepurpose() throws Exception {
         internalCluster().stopRandomNode(s -> true);
         internalCluster().stopRandomNode(s -> true);
 
-        executeRepurposeCommand(noMasterNoDataSettingsForMasterNode, 1, 0);
+        executeRepurposeCommand(noClusterManagerNoDataSettingsForClusterManagerNode, 1, 0);
 
-        // by restarting as master and data node, we can check that the index definition was really deleted and also that the tool
-        // does not mess things up so much that the nodes cannot boot as master or data node any longer.
-        internalCluster().startMasterOnlyNode(masterNodeDataPathSettings);
+        // by restarting as cluster-manager and data node, we can check that the index definition was really deleted and also that the tool
+        // does not mess things up so much that the nodes cannot boot as cluster-manager or data node any longer.
+        internalCluster().startClusterManagerOnlyNode(clusterManagerNodeDataPathSettings);
         internalCluster().startDataOnlyNode(dataNodeDataPathSettings);
 
         ensureGreen();
@@ -136,7 +135,7 @@ private void executeRepurposeCommand(Settings settings, int expectedIndexCount,
         boolean verbose = randomBoolean();
         Settings settingsWithPath = Settings.builder().put(internalCluster().getDefaultSettings()).put(settings).build();
         Matcher<String> matcher = allOf(
-            containsString(NodeRepurposeCommand.noMasterMessage(expectedIndexCount, expectedShardCount, 0)),
+            containsString(NodeRepurposeCommand.noClusterManagerMessage(expectedIndexCount, expectedShardCount, 0)),
             NodeRepurposeCommandTests.conditionalNot(containsString("test-repurpose"), verbose == false)
         );
         NodeRepurposeCommandTests.verifySuccess(settingsWithPath, matcher, verbose);
diff --git a/server/src/internalClusterTest/java/org/opensearch/explain/ExplainActionIT.java b/server/src/internalClusterTest/java/org/opensearch/explain/ExplainActionIT.java
index 53da0309aa602..2949fa34a0795 100644
--- a/server/src/internalClusterTest/java/org/opensearch/explain/ExplainActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/explain/ExplainActionIT.java
@@ -35,10 +35,10 @@
 import org.apache.lucene.search.Explanation;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.explain.ExplainResponse;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/extensions/ExtensionsManagerIT.java b/server/src/internalClusterTest/java/org/opensearch/extensions/ExtensionsManagerIT.java
new file mode 100644
index 0000000000000..3c72edc98c764
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/extensions/ExtensionsManagerIT.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class ExtensionsManagerIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.EXTENSIONS, "true").build();
+    }
+
+    public void testExtensionsManagerCreation() {
+        String nodeName = internalCluster().startNode();
+
+        ensureGreen();
+
+        ExtensionsManager extManager = internalCluster().getInstance(ExtensionsManager.class, nodeName);
+
+        assertEquals(ExtensionsManager.class.getName(), extManager.getClass().getName());
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/GatewayIndexStateIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/GatewayIndexStateIT.java
index a8828c7ad38b5..47ef55bd61290 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/GatewayIndexStateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/GatewayIndexStateIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -61,10 +60,10 @@
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.indices.ShardLimitValidator;
+import org.opensearch.test.InternalTestCluster.RestartCallback;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster.RestartCallback;
 
 import java.io.IOException;
 import java.nio.file.Path;
@@ -241,16 +240,16 @@ public void testSimpleOpenClose() throws Exception {
         client().prepareIndex("test").setId("2").setSource("field1", "value1").execute().actionGet();
     }
 
-    public void testJustMasterNode() throws Exception {
+    public void testJustClusterManagerNode() throws Exception {
         logger.info("--> cleaning nodes");
 
-        logger.info("--> starting 1 master node non data");
+        logger.info("--> starting 1 cluster-manager node non data");
         internalCluster().startNode(nonDataNode());
 
         logger.info("--> create an index");
         client().admin().indices().prepareCreate("test").setWaitForActiveShards(ActiveShardCount.NONE).execute().actionGet();
 
-        logger.info("--> restarting master node");
+        logger.info("--> restarting cluster-manager node");
         internalCluster().fullRestart(new RestartCallback() {
             @Override
             public Settings onNodeStopped(String nodeName) {
@@ -273,11 +272,11 @@ public Settings onNodeStopped(String nodeName) {
         assertThat(clusterStateResponse.getState().metadata().hasIndex("test"), equalTo(true));
     }
 
-    public void testJustMasterNodeAndJustDataNode() {
+    public void testJustClusterManagerNodeAndJustDataNode() {
         logger.info("--> cleaning nodes");
 
-        logger.info("--> starting 1 master node non data");
-        internalCluster().startMasterOnlyNode();
+        logger.info("--> starting 1 cluster-manager node non data");
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
 
         logger.info("--> create an index");
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/MetadataNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/MetadataNodesIT.java
index c9807aa24e259..681b112428c92 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/MetadataNodesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/MetadataNodesIT.java
@@ -36,16 +36,15 @@
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse;
 import org.opensearch.cluster.coordination.Coordinator;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.InternalTestCluster.RestartCallback;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
-import org.opensearch.test.InternalTestCluster.RestartCallback;
 
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -60,18 +59,18 @@
 public class MetadataNodesIT extends OpenSearchIntegTestCase {
     public void testMetaWrittenAlsoOnDataNode() throws Exception {
         // this test checks that index state is written on data only nodes if they have a shard allocated
-        String masterNode = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         String dataNode = internalCluster().startDataOnlyNode(Settings.EMPTY);
         assertAcked(prepareCreate("test").setSettings(Settings.builder().put("index.number_of_replicas", 0)));
         index("test", "_doc", "1", jsonBuilder().startObject().field("text", "some text").endObject());
         ensureGreen("test");
         assertIndexInMetaState(dataNode, "test");
-        assertIndexInMetaState(masterNode, "test");
+        assertIndexInMetaState(clusterManagerNode, "test");
     }
 
     public void testIndexFilesAreRemovedIfAllShardsFromIndexRemoved() throws Exception {
         // this test checks that the index data is removed from a data only node once all shards have been allocated away from it
-        String masterNode = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         List<String> nodeNames = internalCluster().startDataOnlyNodes(2);
         String node1 = nodeNames.get(0);
         String node2 = nodeNames.get(1);
@@ -90,8 +89,8 @@ public void testIndexFilesAreRemovedIfAllShardsFromIndexRemoved() throws Excepti
         Index resolveIndex = resolveIndex(index);
         assertIndexDirectoryExists(node1, resolveIndex);
         assertIndexDirectoryDeleted(node2, resolveIndex);
-        assertIndexInMetaState(masterNode, index);
-        assertIndexDirectoryDeleted(masterNode, resolveIndex);
+        assertIndexInMetaState(clusterManagerNode, index);
+        assertIndexDirectoryDeleted(clusterManagerNode, resolveIndex);
 
         logger.debug("relocating index...");
         client().admin()
@@ -104,8 +103,8 @@ public void testIndexFilesAreRemovedIfAllShardsFromIndexRemoved() throws Excepti
         assertIndexDirectoryDeleted(node1, resolveIndex);
         assertIndexInMetaState(node2, index);
         assertIndexDirectoryExists(node2, resolveIndex);
-        assertIndexInMetaState(masterNode, index);
-        assertIndexDirectoryDeleted(masterNode, resolveIndex);
+        assertIndexInMetaState(clusterManagerNode, index);
+        assertIndexDirectoryDeleted(clusterManagerNode, resolveIndex);
 
         client().admin().indices().prepareDelete(index).get();
         assertIndexDirectoryDeleted(node1, resolveIndex);
@@ -114,7 +113,7 @@ public void testIndexFilesAreRemovedIfAllShardsFromIndexRemoved() throws Excepti
 
     @SuppressWarnings("unchecked")
     public void testMetaWrittenWhenIndexIsClosedAndMetaUpdated() throws Exception {
-        String masterNode = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         final String dataNode = internalCluster().startDataOnlyNode(Settings.EMPTY);
 
         final String index = "index";
@@ -123,7 +122,7 @@ public void testMetaWrittenWhenIndexIsClosedAndMetaUpdated() throws Exception {
         ensureGreen();
         logger.info("--> wait for meta state written for index");
         assertIndexInMetaState(dataNode, index);
-        assertIndexInMetaState(masterNode, index);
+        assertIndexInMetaState(clusterManagerNode, index);
 
         logger.info("--> close index");
         client().admin().indices().prepareClose(index).get();
@@ -152,7 +151,7 @@ public void testMetaWrittenWhenIndexIsClosedAndMetaUpdated() throws Exception {
         );
 
         // make sure it was also written on red node although index is closed
-        ImmutableOpenMap<String, IndexMetadata> indicesMetadata = getIndicesMetadataOnNode(dataNode);
+        Map<String, IndexMetadata> indicesMetadata = getIndicesMetadataOnNode(dataNode);
         assertNotNull(((Map<String, ?>) (indicesMetadata.get(index).mapping().getSourceAsMap().get("properties"))).get("integer_field"));
         assertThat(indicesMetadata.get(index).getState(), equalTo(IndexMetadata.State.CLOSE));
 
@@ -239,7 +238,7 @@ private boolean indexDirectoryExists(String nodeName, Index index) {
         return false;
     }
 
-    private ImmutableOpenMap<String, IndexMetadata> getIndicesMetadataOnNode(String nodeName) {
+    private Map<String, IndexMetadata> getIndicesMetadataOnNode(String nodeName) {
         final Coordinator coordinator = (Coordinator) internalCluster().getInstance(Discovery.class, nodeName);
         return coordinator.getApplierState().getMetadata().getIndices();
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/QuorumGatewayIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/QuorumGatewayIT.java
index 1e190d3bec345..1d494832d8e55 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/QuorumGatewayIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/QuorumGatewayIT.java
@@ -35,10 +35,10 @@
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.test.InternalTestCluster.RestartCallback;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster.RestartCallback;
 
 import java.util.concurrent.TimeUnit;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/RecoverAfterNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/RecoverAfterNodesIT.java
index 7365ef1c8847d..b81bfe6b0a51a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/RecoverAfterNodesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/RecoverAfterNodesIT.java
@@ -43,8 +43,8 @@
 
 import java.util.Set;
 
+import static org.opensearch.test.NodeRoles.clusterManagerOnlyNode;
 import static org.opensearch.test.NodeRoles.dataOnlyNode;
-import static org.opensearch.test.NodeRoles.masterOnlyNode;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
 
@@ -75,7 +75,7 @@ public Client startNode(Settings.Builder settings) {
     }
 
     public void testRecoverAfterNodes() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         logger.info("--> start node (1)");
         Client clientNode1 = startNode(Settings.builder().put("gateway.recover_after_nodes", 3));
         assertThat(
@@ -127,12 +127,12 @@ public void testRecoverAfterNodes() throws Exception {
         assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, clientNode3).isEmpty(), equalTo(true));
     }
 
-    public void testRecoverAfterMasterNodes() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        logger.info("--> start master_node (1)");
-        Client master1 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(masterOnlyNode()));
+    public void testRecoverAfterClusterManagerNodes() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        logger.info("--> start cluster_manager_node (1)");
+        Client clusterManager1 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(clusterManagerOnlyNode()));
         assertThat(
-            master1.admin()
+            clusterManager1.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -147,7 +147,7 @@ public void testRecoverAfterMasterNodes() throws Exception {
         logger.info("--> start data_node (1)");
         Client data1 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(dataOnlyNode()));
         assertThat(
-            master1.admin()
+            clusterManager1.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -174,7 +174,7 @@ public void testRecoverAfterMasterNodes() throws Exception {
         logger.info("--> start data_node (2)");
         Client data2 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(dataOnlyNode()));
         assertThat(
-            master1.admin()
+            clusterManager1.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -210,20 +210,20 @@ public void testRecoverAfterMasterNodes() throws Exception {
             hasItem(GatewayService.STATE_NOT_RECOVERED_BLOCK)
         );
 
-        logger.info("--> start master_node (2)");
-        Client master2 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(masterOnlyNode()));
-        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, master1).isEmpty(), equalTo(true));
-        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, master2).isEmpty(), equalTo(true));
+        logger.info("--> start cluster_manager_node (2)");
+        Client clusterManager2 = startNode(Settings.builder().put("gateway.recover_after_master_nodes", 2).put(clusterManagerOnlyNode()));
+        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, clusterManager1).isEmpty(), equalTo(true));
+        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, clusterManager2).isEmpty(), equalTo(true));
         assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, data1).isEmpty(), equalTo(true));
         assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, data2).isEmpty(), equalTo(true));
     }
 
     public void testRecoverAfterDataNodes() throws Exception {
-        internalCluster().setBootstrapMasterNodeIndex(0);
-        logger.info("--> start master_node (1)");
-        Client master1 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(masterOnlyNode()));
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        logger.info("--> start cluster_manager_node (1)");
+        Client clusterManager1 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(clusterManagerOnlyNode()));
         assertThat(
-            master1.admin()
+            clusterManager1.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -238,7 +238,7 @@ public void testRecoverAfterDataNodes() throws Exception {
         logger.info("--> start data_node (1)");
         Client data1 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(dataOnlyNode()));
         assertThat(
-            master1.admin()
+            clusterManager1.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -262,10 +262,10 @@ public void testRecoverAfterDataNodes() throws Exception {
             hasItem(GatewayService.STATE_NOT_RECOVERED_BLOCK)
         );
 
-        logger.info("--> start master_node (2)");
-        Client master2 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(masterOnlyNode()));
+        logger.info("--> start cluster_manager_node (2)");
+        Client clusterManager2 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(clusterManagerOnlyNode()));
         assertThat(
-            master2.admin()
+            clusterManager2.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -289,7 +289,7 @@ public void testRecoverAfterDataNodes() throws Exception {
             hasItem(GatewayService.STATE_NOT_RECOVERED_BLOCK)
         );
         assertThat(
-            master2.admin()
+            clusterManager2.admin()
                 .cluster()
                 .prepareState()
                 .setLocal(true)
@@ -303,8 +303,8 @@ public void testRecoverAfterDataNodes() throws Exception {
 
         logger.info("--> start data_node (2)");
         Client data2 = startNode(Settings.builder().put("gateway.recover_after_data_nodes", 2).put(dataOnlyNode()));
-        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, master1).isEmpty(), equalTo(true));
-        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, master2).isEmpty(), equalTo(true));
+        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, clusterManager1).isEmpty(), equalTo(true));
+        assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, clusterManager2).isEmpty(), equalTo(true));
         assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, data1).isEmpty(), equalTo(true));
         assertThat(waitForNoBlocksOnNode(BLOCK_WAIT_TIMEOUT, data2).isEmpty(), equalTo(true));
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/RecoveryFromGatewayIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/RecoveryFromGatewayIT.java
index 92d8dc6a0bb5e..229cd7bffad2f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/RecoveryFromGatewayIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/RecoveryFromGatewayIT.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-
 import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
 import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
 import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsAction;
@@ -48,26 +46,26 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.InternalTestCluster.RestartCallback;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalSettingsPlugin;
-import org.opensearch.test.InternalTestCluster.RestartCallback;
 import org.opensearch.test.store.MockFSIndexStore;
 
 import java.nio.file.DirectoryStream;
@@ -111,16 +109,15 @@ public void testOneNodeRecoverFromGateway() throws Exception {
 
         internalCluster().startNode();
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("appAccountIds")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("appAccountIds")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertAcked(prepareCreate("test").setMapping(mapping));
 
         client().prepareIndex("test")
@@ -180,8 +177,7 @@ private Map<String, long[]> assertAndCapturePrimaryTerms(Map<String, long[]> pre
         }
         final Map<String, long[]> result = new HashMap<>();
         final ClusterState state = client().admin().cluster().prepareState().get().getState();
-        for (ObjectCursor<IndexMetadata> cursor : state.metadata().indices().values()) {
-            final IndexMetadata indexMetadata = cursor.value;
+        for (final IndexMetadata indexMetadata : state.metadata().indices().values()) {
             final String index = indexMetadata.getIndex().getName();
             final long[] previous = previousTerms.get(index);
             final long[] current = IntStream.range(0, indexMetadata.getNumberOfShards()).mapToLong(indexMetadata::primaryTerm).toArray();
@@ -206,19 +202,18 @@ private Map<String, long[]> assertAndCapturePrimaryTerms(Map<String, long[]> pre
     public void testSingleNodeNoFlush() throws Exception {
         internalCluster().startNode();
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "text")
-                .endObject()
-                .startObject("num")
-                .field("type", "integer")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .endObject()
+            .startObject("num")
+            .field("type", "integer")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         // note: default replica settings are tied to #data nodes-1 which is 0 here. We can do with 1 in this test.
         int numberOfShards = numberOfShards();
         assertAcked(
@@ -444,7 +439,7 @@ public void testLatestVersionLoaded() throws Exception {
             .setSource(jsonBuilder().startObject().field("field", "value3").endObject())
             .execute()
             .actionGet();
-        // TODO: remove once refresh doesn't fail immediately if there a master block:
+        // TODO: remove once refresh doesn't fail immediately if there a cluster-manager block:
         // https://github.com/elastic/elasticsearch/issues/9997
         // client().admin().cluster().prepareHealth("test").setWaitForYellowStatus().get();
         logger.info("--> refreshing all indices after indexing is complete");
@@ -511,7 +506,7 @@ public void testLatestVersionLoaded() throws Exception {
     }
 
     public void testReuseInFileBasedPeerRecovery() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String primaryNode = internalCluster().startDataOnlyNode(nodeSettings(0));
 
         // create the index with our mapping
@@ -524,7 +519,7 @@ public void testReuseInFileBasedPeerRecovery() throws Exception {
                     .put("number_of_replicas", 1)
 
                     // disable merges to keep segments the same
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
 
                     // expire retention leases quickly
                     .put(IndexService.RETENTION_LEASE_SYNC_INTERVAL_SETTING.getKey(), "100ms")
@@ -547,7 +542,7 @@ public void testReuseInFileBasedPeerRecovery() throws Exception {
         final Set<String> files = new HashSet<>();
         for (final RecoveryState recoveryState : initialRecoveryReponse.shardRecoveryStates().get("test")) {
             if (recoveryState.getTargetNode().getName().equals(replicaNode)) {
-                for (final RecoveryState.FileDetail file : recoveryState.getIndex().fileDetails()) {
+                for (final ReplicationLuceneIndex.FileMetadata file : recoveryState.getIndex().fileDetails()) {
                     files.add(file.name());
                 }
                 break;
@@ -607,7 +602,7 @@ public Settings onNodeStopped(String nodeName) throws Exception {
             long reused = 0;
             int filesRecovered = 0;
             int filesReused = 0;
-            for (final RecoveryState.FileDetail file : recoveryState.getIndex().fileDetails()) {
+            for (final ReplicationLuceneIndex.FileMetadata file : recoveryState.getIndex().fileDetails()) {
                 if (files.contains(file.name()) == false) {
                     recovered += file.length();
                     filesRecovered++;
@@ -664,7 +659,7 @@ public void assertSyncIdsNotNull() {
     }
 
     public void testStartedShardFoundIfStateNotYetProcessed() throws Exception {
-        // nodes may need to report the shards they processed the initial recovered cluster state from the master
+        // nodes may need to report the shards they processed the initial recovered cluster state from the cluster-manager
         final String nodeName = internalCluster().startNode();
         createIndex("test", Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).build());
         final String customDataPath = IndexMetadata.INDEX_DATA_PATH_SETTING.get(
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/ReplicaShardAllocatorIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/ReplicaShardAllocatorIT.java
index 345ed668a3bf4..4c668dcf0c974 100644
--- a/server/src/internalClusterTest/java/org/opensearch/gateway/ReplicaShardAllocatorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/ReplicaShardAllocatorIT.java
@@ -39,10 +39,10 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.seqno.ReplicationTracker;
@@ -54,9 +54,9 @@
 import org.opensearch.indices.recovery.RecoveryCleanFilesRequest;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
 
@@ -327,7 +327,7 @@ public void testFullClusterRestartPerformNoopRecovery() throws Exception {
 
     public void testPreferCopyWithHighestMatchingOperations() throws Exception {
         String indexName = "test";
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNodes(3);
         assertAcked(
             client().admin()
@@ -402,7 +402,7 @@ public void testPreferCopyWithHighestMatchingOperations() throws Exception {
      * Make sure that we do not repeatedly cancel an ongoing recovery for a noop copy on a broken node.
      */
     public void testDoNotCancelRecoveryForBrokenNode() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         String nodeWithPrimary = internalCluster().startDataOnlyNode();
         String indexName = "test";
         assertAcked(
@@ -518,7 +518,7 @@ public void testPeerRecoveryForClosedIndices() throws Exception {
      * this behavior by changing the global checkpoint in phase1 to unassigned.
      */
     public void testSimulateRecoverySourceOnOldNode() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         String source = internalCluster().startDataOnlyNode();
         String indexName = "test";
         assertAcked(
diff --git a/server/src/internalClusterTest/java/org/opensearch/gateway/remote/RemoteClusterStateServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/gateway/remote/RemoteClusterStateServiceIT.java
new file mode 100644
index 0000000000000..6fcc89cfe9e9a
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/gateway/remote/RemoteClusterStateServiceIT.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gateway.remote;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.remotestore.RemoteStoreBaseIntegTestCase;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.Map;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.gateway.remote.RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteClusterStateServiceIT extends RemoteStoreBaseIntegTestCase {
+
+    private static String INDEX_NAME = "test-index";
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder().put(super.nodeSettings(nodeOrdinal)).put(REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true).build();
+    }
+
+    private void prepareCluster(int numClusterManagerNodes, int numDataOnlyNodes, String indices, int replicaCount, int shardCount) {
+        internalCluster().startClusterManagerOnlyNodes(numClusterManagerNodes);
+        internalCluster().startDataOnlyNodes(numDataOnlyNodes);
+        for (String index : indices.split(",")) {
+            createIndex(index, remoteStoreIndexSettings(replicaCount, shardCount));
+            ensureYellowAndNoInitializingShards(index);
+            ensureGreen(index);
+        }
+    }
+
+    private Map<String, Long> initialTestSetup(int shardCount, int replicaCount, int dataNodeCount, int clusterManagerNodeCount) {
+        prepareCluster(clusterManagerNodeCount, dataNodeCount, INDEX_NAME, replicaCount, shardCount);
+        Map<String, Long> indexStats = indexData(1, false, INDEX_NAME);
+        assertEquals(shardCount * (replicaCount + 1), getNumShards(INDEX_NAME).totalNumShards);
+        ensureGreen(INDEX_NAME);
+        return indexStats;
+    }
+
+    public void testFullClusterRestoreStaleDelete() throws Exception {
+        int shardCount = randomIntBetween(1, 2);
+        int replicaCount = 1;
+        int dataNodeCount = shardCount * (replicaCount + 1);
+        int clusterManagerNodeCount = 1;
+
+        initialTestSetup(shardCount, replicaCount, dataNodeCount, clusterManagerNodeCount);
+        setReplicaCount(0);
+        setReplicaCount(2);
+        setReplicaCount(0);
+        setReplicaCount(1);
+        setReplicaCount(0);
+        setReplicaCount(1);
+        setReplicaCount(0);
+        setReplicaCount(2);
+        setReplicaCount(0);
+
+        RemoteClusterStateService remoteClusterStateService = internalCluster().getClusterManagerNodeInstance(
+            RemoteClusterStateService.class
+        );
+
+        RepositoriesService repositoriesService = internalCluster().getClusterManagerNodeInstance(RepositoriesService.class);
+
+        BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(REPOSITORY_NAME);
+        BlobPath baseMetadataPath = repository.basePath()
+            .add(
+                Base64.getUrlEncoder()
+                    .withoutPadding()
+                    .encodeToString(getClusterState().getClusterName().value().getBytes(StandardCharsets.UTF_8))
+            )
+            .add("cluster-state")
+            .add(getClusterState().metadata().clusterUUID());
+
+        assertEquals(10, repository.blobStore().blobContainer(baseMetadataPath.add("manifest")).listBlobsByPrefix("manifest").size());
+
+        Map<String, IndexMetadata> indexMetadataMap = remoteClusterStateService.getLatestIndexMetadata(
+            cluster().getClusterName(),
+            getClusterState().metadata().clusterUUID()
+        );
+        assertEquals(0, indexMetadataMap.values().stream().findFirst().get().getNumberOfReplicas());
+        assertEquals(shardCount, indexMetadataMap.values().stream().findFirst().get().getNumberOfShards());
+    }
+
+    private void setReplicaCount(int replicaCount) {
+        client().admin()
+            .indices()
+            .prepareUpdateSettings(INDEX_NAME)
+            .setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, replicaCount))
+            .get();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/get/GetActionIT.java b/server/src/internalClusterTest/java/org/opensearch/get/GetActionIT.java
index 2f811d4a901bf..c44b7c7736d21 100644
--- a/server/src/internalClusterTest/java/org/opensearch/get/GetActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/get/GetActionIT.java
@@ -35,7 +35,6 @@
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.flush.FlushResponse;
-
 import org.opensearch.action.delete.DeleteResponse;
 import org.opensearch.action.get.GetRequestBuilder;
 import org.opensearch.action.get.GetResponse;
@@ -43,19 +42,19 @@
 import org.opensearch.action.get.MultiGetRequestBuilder;
 import org.opensearch.action.get.MultiGetResponse;
 import org.opensearch.action.index.IndexResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -288,17 +287,16 @@ public void testSimpleMultiGet() throws Exception {
     }
 
     public void testGetDocWithMultivaluedFields() throws Exception {
-        String mapping1 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "text")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping1 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertAcked(prepareCreate("test").setMapping(mapping1));
         ensureGreen();
 
@@ -633,7 +631,7 @@ public void testGetFieldsComplexField() throws Exception {
 
         logger.info("indexing documents");
 
-        client().prepareIndex("my-index").setId("1").setSource(source, XContentType.JSON).get();
+        client().prepareIndex("my-index").setId("1").setSource(source, MediaTypeRegistry.JSON).get();
 
         logger.info("checking real time retrieval");
 
@@ -692,7 +690,7 @@ public void testUngeneratedFieldsThatAreNeverStored() throws IOException {
             + "    }\n"
             + "  }\n"
             + "}";
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, MediaTypeRegistry.JSON));
         ensureGreen();
         String doc = "{\n"
             + "  \"suggest\": {\n"
@@ -722,10 +720,10 @@ public void testUngeneratedFieldsThatAreAlwaysStored() throws IOException {
             + "    \"refresh_interval\": \"-1\"\n"
             + "  }\n"
             + "}";
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, MediaTypeRegistry.JSON));
         ensureGreen();
 
-        client().prepareIndex("test").setId("1").setRouting("routingValue").setId("1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setRouting("routingValue").setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
 
         String[] fieldsList = { "_routing" };
         // before refresh - document is only in translog
@@ -746,10 +744,10 @@ public void testUngeneratedFieldsNotPartOfSourceStored() throws IOException {
             + "  }\n"
             + "}";
 
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, MediaTypeRegistry.JSON));
         ensureGreen();
         String doc = "{\n" + "  \"text\": \"some text.\"\n" + "}\n";
-        client().prepareIndex("test").setId("1").setSource(doc, XContentType.JSON).setRouting("1").get();
+        client().prepareIndex("test").setId("1").setSource(doc, MediaTypeRegistry.JSON).setRouting("1").get();
         String[] fieldsList = { "_routing" };
         // before refresh - document is only in translog
         assertGetFieldsAlwaysWorks(indexOrAlias(), "_doc", "1", fieldsList, "1");
@@ -817,7 +815,7 @@ void indexSingleDocumentWithStringFieldsGeneratedFromText(boolean stored, boolea
             + "  }\n"
             + "}";
 
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, MediaTypeRegistry.JSON));
         ensureGreen();
         String doc = "{\n" + "  \"text1\": \"some text.\"\n," + "  \"text2\": \"more text.\"\n" + "}\n";
         index("test", "_doc", "1", doc);
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/FinalPipelineIT.java b/server/src/internalClusterTest/java/org/opensearch/index/FinalPipelineIT.java
index 3b2695ad7896e..03b8fb5ff7afc 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/FinalPipelineIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/FinalPipelineIT.java
@@ -45,12 +45,13 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.ingest.AbstractProcessor;
@@ -60,12 +61,10 @@
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.ScriptService;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.watcher.ResourceWatcherService;
-
 import org.junit.After;
 
 import java.io.IOException;
@@ -103,7 +102,10 @@ public void testFinalPipelineCantChangeDestination() {
         createIndex("index", settings);
 
         final BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"changing_dest\": {}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
 
         final IllegalStateException e = expectThrows(
             IllegalStateException.class,
@@ -122,11 +124,14 @@ public void testFinalPipelineOfOldDestinationIsNotInvoked() {
         BytesReference defaultPipelineBody = new BytesArray("{\"processors\": [{\"changing_dest\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
 
         BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"final\": {\"exists\":\"no_such_field\"}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
 
         IndexResponse indexResponse = client().prepareIndex("index")
             .setId("1")
@@ -149,11 +154,14 @@ public void testFinalPipelineOfNewDestinationIsInvoked() {
         BytesReference defaultPipelineBody = new BytesArray("{\"processors\": [{\"changing_dest\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
 
         BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"final\": {}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
 
         IndexResponse indexResponse = client().prepareIndex("index")
             .setId("1")
@@ -176,13 +184,13 @@ public void testDefaultPipelineOfNewDestinationIsNotInvoked() {
         BytesReference defaultPipelineBody = new BytesArray("{\"processors\": [{\"changing_dest\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
 
         BytesReference targetPipeline = new BytesArray("{\"processors\": [{\"final\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("target_default_pipeline", targetPipeline, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("target_default_pipeline", targetPipeline, MediaTypeRegistry.JSON))
             .actionGet();
 
         IndexResponse indexResponse = client().prepareIndex("index")
@@ -212,10 +220,13 @@ public void testRequestPipelineAndFinalPipeline() {
         final BytesReference requestPipelineBody = new BytesArray("{\"processors\": [{\"request\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("request_pipeline", requestPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("request_pipeline", requestPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
         final BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"final\": {\"exists\":\"request\"}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
         final Settings settings = Settings.builder().put(IndexSettings.FINAL_PIPELINE.getKey(), "final_pipeline").build();
         createIndex("index", settings);
         final IndexRequestBuilder index = client().prepareIndex("index").setId("1");
@@ -238,10 +249,13 @@ public void testDefaultAndFinalPipeline() {
         final BytesReference defaultPipelineBody = new BytesArray("{\"processors\": [{\"default\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
         final BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"final\": {\"exists\":\"default\"}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
         final Settings settings = Settings.builder()
             .put(IndexSettings.DEFAULT_PIPELINE.getKey(), "default_pipeline")
             .put(IndexSettings.FINAL_PIPELINE.getKey(), "final_pipeline")
@@ -266,10 +280,13 @@ public void testDefaultAndFinalPipelineFromTemplates() {
         final BytesReference defaultPipelineBody = new BytesArray("{\"processors\": [{\"default\": {}}]}");
         client().admin()
             .cluster()
-            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, XContentType.JSON))
+            .putPipeline(new PutPipelineRequest("default_pipeline", defaultPipelineBody, MediaTypeRegistry.JSON))
             .actionGet();
         final BytesReference finalPipelineBody = new BytesArray("{\"processors\": [{\"final\": {\"exists\":\"default\"}}]}");
-        client().admin().cluster().putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, XContentType.JSON)).actionGet();
+        client().admin()
+            .cluster()
+            .putPipeline(new PutPipelineRequest("final_pipeline", finalPipelineBody, MediaTypeRegistry.JSON))
+            .actionGet();
         final int lowOrder = randomIntBetween(0, Integer.MAX_VALUE - 1);
         final int highOrder = randomIntBetween(lowOrder + 1, Integer.MAX_VALUE);
         final int finalPipelineOrder;
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/IndexRequestBuilderIT.java b/server/src/internalClusterTest/java/org/opensearch/index/IndexRequestBuilderIT.java
index 9432f28a0a59e..57bdaff645838 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/IndexRequestBuilderIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/IndexRequestBuilderIT.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
@@ -54,11 +54,11 @@ public void testSetSource() throws InterruptedException, ExecutionException {
         map.put("test_field", "foobar");
         IndexRequestBuilder[] builders = new IndexRequestBuilder[] {
             client().prepareIndex("test").setSource("test_field", "foobar"),
-            client().prepareIndex("test").setSource("{\"test_field\" : \"foobar\"}", XContentType.JSON),
-            client().prepareIndex("test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), XContentType.JSON),
-            client().prepareIndex("test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), XContentType.JSON),
+            client().prepareIndex("test").setSource("{\"test_field\" : \"foobar\"}", MediaTypeRegistry.JSON),
+            client().prepareIndex("test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), MediaTypeRegistry.JSON),
+            client().prepareIndex("test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), MediaTypeRegistry.JSON),
             client().prepareIndex("test")
-                .setSource(BytesReference.toBytes(new BytesArray("{\"test_field\" : \"foobar\"}")), XContentType.JSON),
+                .setSource(BytesReference.toBytes(new BytesArray("{\"test_field\" : \"foobar\"}")), MediaTypeRegistry.JSON),
             client().prepareIndex("test").setSource(map) };
         indexRandom(true, builders);
         SearchResponse searchResponse = client().prepareSearch("test").setQuery(QueryBuilders.termQuery("test_field", "foobar")).get();
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/IndexSortIT.java b/server/src/internalClusterTest/java/org/opensearch/index/IndexSortIT.java
index 69eb34c39c10c..bb6e356db188f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/IndexSortIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/IndexSortIT.java
@@ -32,22 +32,45 @@
 
 package org.opensearch.index;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSortField;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.containsString;
 
-public class IndexSortIT extends OpenSearchIntegTestCase {
+public class IndexSortIT extends ParameterizedOpenSearchIntegTestCase {
     private static final XContentBuilder TEST_MAPPING = createTestMapping();
 
+    public IndexSortIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private static XContentBuilder createTestMapping() {
         try {
             return jsonBuilder().startObject()
@@ -81,8 +104,8 @@ private static XContentBuilder createTestMapping() {
     public void testIndexSort() {
         SortField dateSort = new SortedNumericSortField("date", SortField.Type.LONG, false);
         dateSort.setMissingValue(Long.MAX_VALUE);
-        SortField numericSort = new SortedNumericSortField("numeric_dv", SortField.Type.LONG, false);
-        numericSort.setMissingValue(Long.MAX_VALUE);
+        SortField numericSort = new SortedNumericSortField("numeric_dv", SortField.Type.INT, false);
+        numericSort.setMissingValue(Integer.MAX_VALUE);
         SortField keywordSort = new SortedSetSortField("keyword_dv", false);
         keywordSort.setMissingValue(SortField.STRING_LAST);
         Sort indexSort = new Sort(dateSort, numericSort, keywordSort);
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/IndexingPressureIT.java b/server/src/internalClusterTest/java/org/opensearch/index/IndexingPressureIT.java
index b461322735ce0..766ae502c0f19 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/IndexingPressureIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/IndexingPressureIT.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.index;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.action.bulk.BulkRequest;
@@ -43,14 +42,15 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -437,7 +437,16 @@ public Settings onNodeStopped(String nodeName) {
     }
 
     private String getCoordinatingOnlyNode() {
-        return client().admin().cluster().prepareState().get().getState().nodes().getCoordinatingOnlyNodes().iterator().next().value
+        return client().admin()
+            .cluster()
+            .prepareState()
+            .get()
+            .getState()
+            .nodes()
+            .getCoordinatingOnlyNodes()
+            .values()
+            .iterator()
+            .next()
             .getName();
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/SegmentReplicationPressureIT.java b/server/src/internalClusterTest/java/org/opensearch/index/SegmentReplicationPressureIT.java
new file mode 100644
index 0000000000000..033ea75b68958
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/index/SegmentReplicationPressureIT.java
@@ -0,0 +1,385 @@
+/*
+ * Copyright OpenSearch Contributors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
+import org.opensearch.action.bulk.BulkItemResponse;
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardState;
+import org.opensearch.indices.replication.SegmentReplicationBaseIT;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.index.SegmentReplicationPressureService.MAX_INDEXING_CHECKPOINTS;
+import static org.opensearch.index.SegmentReplicationPressureService.MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING;
+import static org.opensearch.index.SegmentReplicationPressureService.MAX_REPLICATION_TIME_BACKPRESSURE_SETTING;
+import static org.opensearch.index.SegmentReplicationPressureService.SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationPressureIT extends SegmentReplicationBaseIT {
+
+    private static final int MAX_CHECKPOINTS_BEHIND = 2;
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+            .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueSeconds(1))
+            .put(MAX_INDEXING_CHECKPOINTS.getKey(), MAX_CHECKPOINTS_BEHIND)
+            .build();
+    }
+
+    @Override
+    public Settings indexSettings() {
+        // we want to control refreshes
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, SHARD_COUNT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put("index.refresh_interval", -1)
+            .build();
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return asList(MockTransportService.TestPlugin.class);
+    }
+
+    public void testWritesRejected() throws Exception {
+        final String primaryNode = internalCluster().startNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+        final List<String> replicaNodes = asList(replicaNode);
+        assertEqualSegmentInfosVersion(replicaNodes, primaryShard);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicInteger totalDocs = new AtomicInteger(0);
+        try (final Releasable ignored = blockReplication(replicaNodes, latch)) {
+            Thread indexingThread = new Thread(() -> { totalDocs.getAndSet(indexUntilCheckpointCount()); });
+            indexingThread.start();
+            indexingThread.join();
+            latch.await();
+
+            indexDoc();
+            totalDocs.incrementAndGet();
+            refresh(INDEX_NAME);
+            // index again while we are stale.
+            assertBusy(() -> {
+                expectThrows(OpenSearchRejectedExecutionException.class, () -> {
+                    indexDoc();
+                    totalDocs.incrementAndGet();
+                });
+            });
+            // Try to index one more doc.
+            expectThrows(OpenSearchRejectedExecutionException.class, () -> {
+                indexDoc();
+                totalDocs.incrementAndGet();
+                refresh(INDEX_NAME);
+            });
+
+            // Verify the rejected doc count.
+            SegmentReplicationStatsResponse segmentReplicationStatsResponse = dataNodeClient().admin()
+                .indices()
+                .prepareSegmentReplicationStats(INDEX_NAME)
+                .setDetailed(true)
+                .execute()
+                .actionGet();
+            SegmentReplicationPerGroupStats perGroupStats = segmentReplicationStatsResponse.getReplicationStats().get(INDEX_NAME).get(0);
+
+            assertEquals(perGroupStats.getRejectedRequestCount(), 2L);
+        }
+        refresh(INDEX_NAME);
+
+        // wait for the replicas to catch up after block is released.
+        assertReplicaCheckpointUpdated(primaryShard);
+        // index another doc showing there is no pressure enforced.
+        indexDoc();
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(totalDocs.incrementAndGet(), replicaNodes.toArray(new String[] {}));
+        verifyStoreContent();
+    }
+
+    /**
+     * This test ensures that a replica can be added while the index is under write block.
+     * Ensuring that only write requests are blocked.
+     */
+    public void testAddReplicaWhileWritesBlocked() throws Exception {
+        final String primaryNode = internalCluster().startNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+        final List<String> replicaNodes = new ArrayList<>();
+        replicaNodes.add(replicaNode);
+        assertEqualSegmentInfosVersion(replicaNodes, primaryShard);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicInteger totalDocs = new AtomicInteger(0);
+        try (final Releasable ignored = blockReplication(replicaNodes, latch)) {
+            Thread indexingThread = new Thread(() -> { totalDocs.getAndSet(indexUntilCheckpointCount()); });
+            indexingThread.start();
+            indexingThread.join();
+            latch.await();
+            indexDoc();
+            totalDocs.incrementAndGet();
+            refresh(INDEX_NAME);
+            // index again while we are stale.
+            assertBusy(() -> {
+                expectThrows(OpenSearchRejectedExecutionException.class, () -> {
+                    indexDoc();
+                    totalDocs.incrementAndGet();
+                });
+            });
+            final String replica_2 = internalCluster().startNode();
+            assertAcked(
+                client().admin()
+                    .indices()
+                    .prepareUpdateSettings(INDEX_NAME)
+                    .setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 2))
+            );
+            replicaNodes.add(replica_2);
+        }
+        ensureGreen(INDEX_NAME);
+        waitForSearchableDocs(totalDocs.get(), replicaNodes);
+        refresh(INDEX_NAME);
+        // wait for the replicas to catch up after block is released.
+        assertReplicaCheckpointUpdated(primaryShard);
+
+        // index another doc showing there is no pressure enforced.
+        indexDoc();
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(totalDocs.incrementAndGet(), replicaNodes.toArray(new String[] {}));
+        verifyStoreContent();
+    }
+
+    public void testBelowReplicaLimit() throws Exception {
+        final Settings settings = Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 3).build();
+        final String primaryNode = internalCluster().startNode();
+        createIndex(INDEX_NAME, settings);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        List<String> replicaNodes = new ArrayList<>();
+        for (int i = 0; i < 3; i++) {
+            replicaNodes.add(internalCluster().startNode());
+        }
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+        assertEqualSegmentInfosVersion(replicaNodes, primaryShard);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicInteger totalDocs = new AtomicInteger(0);
+        // only block a single replica, pressure should not get applied.
+        try (final Releasable ignored = blockReplication(replicaNodes.subList(0, 1), latch)) {
+            Thread indexingThread = new Thread(() -> totalDocs.getAndSet(indexUntilCheckpointCount()));
+            indexingThread.start();
+            indexingThread.join();
+            latch.await();
+            indexDoc();
+            totalDocs.incrementAndGet();
+            refresh(INDEX_NAME);
+        }
+        // index another doc showing there is no pressure enforced.
+        indexDoc();
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(totalDocs.incrementAndGet(), replicaNodes.toArray(new String[] {}));
+        verifyStoreContent();
+    }
+
+    public void testFailStaleReplica() throws Exception {
+
+        Settings settings = Settings.builder()
+            .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueMillis(500))
+            .put(MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING.getKey(), TimeValue.timeValueMillis(1000))
+            .build();
+        // Starts a primary and replica node.
+        final String primaryNode = internalCluster().startNode(settings);
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode(settings);
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+        final List<String> replicaNodes = asList(replicaNode);
+        assertEqualSegmentInfosVersion(replicaNodes, primaryShard);
+        IndexShard replicaShard = getIndexShard(replicaNode, INDEX_NAME);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicInteger totalDocs = new AtomicInteger(0);
+        try (final Releasable ignored = blockReplication(replicaNodes, latch)) {
+            // Index docs until replicas are staled.
+            totalDocs.getAndSet(indexUntilCheckpointCount());
+            latch.await();
+            // index again while we are stale.
+            indexDoc();
+            refresh(INDEX_NAME);
+            totalDocs.incrementAndGet();
+
+            // Verify that replica shard is closed.
+            assertBusy(() -> { assertTrue(replicaShard.state().equals(IndexShardState.CLOSED)); }, 1, TimeUnit.MINUTES);
+        }
+        ensureGreen(INDEX_NAME);
+        final IndexShard replicaAfterFailure = getIndexShard(replicaNode, INDEX_NAME);
+
+        // Verify that new replica shard after failure is different from old replica shard.
+        assertNotEquals(replicaAfterFailure.routingEntry().allocationId().getId(), replicaShard.routingEntry().allocationId().getId());
+    }
+
+    public void testWithDocumentReplicationEnabledIndex() throws Exception {
+        assumeFalse(
+            "Skipping the test as its not compatible with segment replication with remote store. Cannot create DocRep indices with Remote store enabled",
+            segmentReplicationWithRemoteEnabled()
+        );
+        Settings settings = Settings.builder()
+            .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueMillis(500))
+            .build();
+        // Starts a primary and replica node.
+        final String primaryNode = internalCluster().startNode(settings);
+        createIndex(
+            INDEX_NAME,
+            Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build()
+        );
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode(settings);
+        ensureGreen(INDEX_NAME);
+        final AtomicInteger totalDocs = new AtomicInteger(0);
+        // Index docs until replica stale limit is reached.
+        totalDocs.getAndSet(indexUntilCheckpointCount());
+        // index again after stale limit.
+        indexDoc();
+        refresh(INDEX_NAME);
+        totalDocs.incrementAndGet();
+        // verify total doc count is same and docs are not rejected.
+        assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), totalDocs.get());
+        assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), totalDocs.get());
+
+    }
+
+    public void testBulkWritesRejected() throws Exception {
+        final String primaryNode = internalCluster().startNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode();
+        final String coordinator = internalCluster().startCoordinatingOnlyNode(Settings.EMPTY);
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+        final List<String> replicaNodes = asList(replicaNode);
+        assertEqualSegmentInfosVersion(replicaNodes, primaryShard);
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        List<String> nodes = List.of(primaryNode, replicaNode, coordinator);
+
+        int docsPerBatch = randomIntBetween(1, 200);
+        int totalDocs = docsPerBatch * MAX_CHECKPOINTS_BEHIND;
+        try (final Releasable ignored = blockReplication(replicaNodes, latch)) {
+            Thread indexingThread = new Thread(() -> {
+                for (int i = 0; i < MAX_CHECKPOINTS_BEHIND + 1; i++) {
+                    executeBulkRequest(nodes, docsPerBatch);
+                    refresh(INDEX_NAME);
+                }
+            });
+            indexingThread.start();
+            indexingThread.join();
+            latch.await();
+            // try and index again while we are stale.
+            assertBusy(() -> { assertFailedRequests(executeBulkRequest(nodes, randomIntBetween(1, 200))); });
+        }
+        refresh(INDEX_NAME);
+        // wait for the replicas to catch up after block is released.
+        assertReplicaCheckpointUpdated(primaryShard);
+
+        // index another doc showing there is no pressure enforced.
+        executeBulkRequest(nodes, totalDocs);
+        waitForSearchableDocs(totalDocs * 2L, replicaNodes.toArray(new String[] {}));
+        verifyStoreContent();
+    }
+
+    private BulkResponse executeBulkRequest(List<String> nodes, int docsPerBatch) {
+        final BulkRequest bulkRequest = new BulkRequest();
+        for (int j = 0; j < docsPerBatch; ++j) {
+            IndexRequest request = new IndexRequest(INDEX_NAME).id(UUIDs.base64UUID())
+                .source(Collections.singletonMap("key", randomAlphaOfLength(50)));
+            bulkRequest.add(request);
+        }
+        final BulkResponse bulkItemResponses = client(randomFrom(nodes)).bulk(bulkRequest).actionGet();
+        refresh(INDEX_NAME);
+        return bulkItemResponses;
+    }
+
+    /**
+     * Index and Refresh in batches to force checkpoints behind.
+     * Asserts that there are no stale replicas according to the primary until cp count is reached.
+     */
+    private int indexUntilCheckpointCount() {
+        int total = 0;
+        for (int i = 0; i < MAX_CHECKPOINTS_BEHIND; i++) {
+            final int numDocs = randomIntBetween(1, 5);
+            for (int j = 0; j < numDocs; ++j) {
+                indexDoc();
+            }
+            total += numDocs;
+            refresh(INDEX_NAME);
+        }
+        return total;
+    }
+
+    private void assertFailedRequests(BulkResponse response) {
+        assertTrue(Arrays.stream(response.getItems()).allMatch(BulkItemResponse::isFailed));
+        assertTrue(
+            Arrays.stream(response.getItems())
+                .map(BulkItemResponse::getFailure)
+                .allMatch((failure) -> failure.getStatus() == RestStatus.TOO_MANY_REQUESTS)
+        );
+    }
+
+    private void indexDoc() {
+        client().prepareIndex(INDEX_NAME).setId(UUIDs.base64UUID()).setSource("{}", "{}").execute().actionGet();
+    }
+
+    private void assertEqualSegmentInfosVersion(List<String> replicaNames, IndexShard primaryShard) {
+        for (String replicaName : replicaNames) {
+            final IndexShard replicaShard = getIndexShard(replicaName, INDEX_NAME);
+            assertEquals(
+                primaryShard.getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                replicaShard.getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureIT.java b/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureIT.java
index f14540cec4e2b..69c394d2da133 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureIT.java
@@ -6,29 +6,30 @@
 package org.opensearch.index;
 
 import org.apache.lucene.util.RamUsageEstimator;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.action.bulk.BulkItemRequest;
 import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.bulk.BulkShardRequest;
 import org.opensearch.action.bulk.TransportShardBulkAction;
-import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -778,7 +779,16 @@ private Tuple<String, String> getPrimaryReplicaNodeNames(String indexName) {
     }
 
     private String getCoordinatingOnlyNode() {
-        return client().admin().cluster().prepareState().get().getState().nodes().getCoordinatingOnlyNodes().iterator().next().value
+        return client().admin()
+            .cluster()
+            .prepareState()
+            .get()
+            .getState()
+            .nodes()
+            .getCoordinatingOnlyNodes()
+            .values()
+            .iterator()
+            .next()
             .getName();
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureSettingsIT.java
index 1cdf8e702aafa..5426f4037294f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/ShardIndexingPressureSettingsIT.java
@@ -6,7 +6,6 @@
 package org.opensearch.index;
 
 import org.apache.lucene.util.RamUsageEstimator;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.admin.indices.stats.ShardStats;
@@ -21,16 +20,18 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -920,7 +921,16 @@ private Tuple<String, String> getPrimaryReplicaNodeNames(String indexName) {
     }
 
     private String getCoordinatingOnlyNode() {
-        return client().admin().cluster().prepareState().get().getState().nodes().getCoordinatingOnlyNodes().iterator().next().value
+        return client().admin()
+            .cluster()
+            .prepareState()
+            .get()
+            .getState()
+            .nodes()
+            .getCoordinatingOnlyNodes()
+            .values()
+            .iterator()
+            .next()
             .getName();
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/WaitUntilRefreshIT.java b/server/src/internalClusterTest/java/org/opensearch/index/WaitUntilRefreshIT.java
index e38b128c04fde..eb1b721cdad25 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/WaitUntilRefreshIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/WaitUntilRefreshIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkRequestBuilder;
@@ -42,14 +41,14 @@
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
 import org.junit.Before;
 
 import java.util.Collection;
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/codec/ZstdNotEnabledIT.java b/server/src/internalClusterTest/java/org/opensearch/index/codec/ZstdNotEnabledIT.java
new file mode 100644
index 0000000000000..9b1fa77fc9a5a
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/index/codec/ZstdNotEnabledIT.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.codec;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
+public class ZstdNotEnabledIT extends OpenSearchIntegTestCase {
+
+    public void testZStdCodecsWithoutPluginInstalled() {
+
+        internalCluster().startNode();
+        final String index = "test-index";
+
+        // creating index with zstd and zstd_no_dict should fail if custom-codecs plugin is not installed
+        for (String codec : List.of("zstd", "zstd_no_dict")) {
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> createIndex(
+                    index,
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                        .put("index.codec", codec)
+                        .build()
+                )
+            );
+        }
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/engine/MaxDocsLimitIT.java b/server/src/internalClusterTest/java/org/opensearch/index/engine/MaxDocsLimitIT.java
index b548d4061475c..385d33c359559 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/engine/MaxDocsLimitIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/engine/MaxDocsLimitIT.java
@@ -36,16 +36,15 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.plugins.EnginePlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
-
 import org.junit.After;
 import org.junit.Before;
 
@@ -204,7 +203,7 @@ static IndexingResult indexDocs(int numRequests, int numThreads) throws Exceptio
                 phaser.arriveAndAwaitAdvance();
                 while (completedRequests.incrementAndGet() <= numRequests) {
                     try {
-                        final IndexResponse resp = client().prepareIndex("test").setSource("{}", XContentType.JSON).get();
+                        final IndexResponse resp = client().prepareIndex("test").setSource("{}", MediaTypeRegistry.JSON).get();
                         numSuccess.incrementAndGet();
                         assertThat(resp.status(), equalTo(RestStatus.CREATED));
                     } catch (IllegalArgumentException e) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/mapper/CopyToMapperIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/index/mapper/CopyToMapperIntegrationIT.java
index d4733e4f31cb2..0df84261ade63 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/mapper/CopyToMapperIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/mapper/CopyToMapperIntegrationIT.java
@@ -33,9 +33,8 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
@@ -78,16 +77,15 @@ public void testDynamicTemplateCopyTo() throws Exception {
     }
 
     public void testDynamicObjectCopyTo() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "text")
-                .field("copy_to", "root.top.child")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "text")
+            .field("copy_to", "root.top.child")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertAcked(client().admin().indices().prepareCreate("test-idx").setMapping(mapping));
         client().prepareIndex("test-idx").setId("1").setSource("foo", "bar").get();
         client().admin().indices().prepareRefresh("test-idx").execute().actionGet();
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/mapper/DynamicMappingIT.java b/server/src/internalClusterTest/java/org/opensearch/index/mapper/DynamicMappingIT.java
index d5924155e2ec7..2267ef1bb6739 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/mapper/DynamicMappingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/mapper/DynamicMappingIT.java
@@ -42,9 +42,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -76,7 +75,7 @@ public void testConflictingDynamicMappings() {
             assertThat(e.getMessage(), Matchers.containsString("failed to parse field [foo] of type [long]"));
         } catch (IllegalArgumentException e) {
             // rare case: the node that processes the index request doesn't have the mappings
-            // yet and sends a mapping update to the master node to map "bar" as "text". This
+            // yet and sends a mapping update to the cluster-manager node to map "bar" as "text". This
             // fails as it had been already mapped as a long by the previous index request.
             assertThat(e.getMessage(), Matchers.containsString("mapper [foo] cannot be changed from type [long] to [text]"));
         }
@@ -140,19 +139,19 @@ public void run() {
         }
     }
 
-    public void testPreflightCheckAvoidsMaster() throws InterruptedException {
+    public void testPreflightCheckAvoidsClusterManager() throws InterruptedException {
         createIndex("index", Settings.builder().put(INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING.getKey(), 2).build());
         ensureGreen("index");
         client().prepareIndex("index").setId("1").setSource("field1", "value1").get();
 
-        final CountDownLatch masterBlockedLatch = new CountDownLatch(1);
+        final CountDownLatch clusterManagerBlockedLatch = new CountDownLatch(1);
         final CountDownLatch indexingCompletedLatch = new CountDownLatch(1);
 
-        internalCluster().getInstance(ClusterService.class, internalCluster().getMasterName())
+        internalCluster().getInstance(ClusterService.class, internalCluster().getClusterManagerName())
             .submitStateUpdateTask("block-state-updates", new ClusterStateUpdateTask() {
                 @Override
                 public ClusterState execute(ClusterState currentState) throws Exception {
-                    masterBlockedLatch.countDown();
+                    clusterManagerBlockedLatch.countDown();
                     indexingCompletedLatch.await();
                     return currentState;
                 }
@@ -163,7 +162,7 @@ public void onFailure(String source, Exception e) {
                 }
             });
 
-        masterBlockedLatch.await();
+        clusterManagerBlockedLatch.await();
         final IndexRequestBuilder indexRequestBuilder = client().prepareIndex("index").setId("2").setSource("field2", "value2");
         try {
             assertThat(
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/mapper/ExternalValuesMapperIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/index/mapper/ExternalValuesMapperIntegrationIT.java
index 138081e56dd63..3734bbbe8aa6c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/mapper/ExternalValuesMapperIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/mapper/ExternalValuesMapperIntegrationIT.java
@@ -40,11 +40,12 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.util.Collection;
 import java.util.Collections;
 
+import org.locationtech.jts.geom.Coordinate;
+
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.equalTo;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/mapper/MultiFieldsIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/index/mapper/MultiFieldsIntegrationIT.java
index 7dbb6a45b857d..50440f9527a6a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/mapper/MultiFieldsIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/mapper/MultiFieldsIntegrationIT.java
@@ -37,9 +37,9 @@
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/search/MatchPhraseQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/index/search/MatchPhraseQueryIT.java
index 6d76ee48a5b95..2d28578dbebcc 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/search/MatchPhraseQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/search/MatchPhraseQueryIT.java
@@ -32,26 +32,50 @@
 
 package org.opensearch.index.search;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.MatchPhraseQueryBuilder;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
 import static org.opensearch.index.query.QueryBuilders.matchPhraseQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 
-public class MatchPhraseQueryIT extends OpenSearchIntegTestCase {
+public class MatchPhraseQueryIT extends ParameterizedOpenSearchIntegTestCase {
+
     private static final String INDEX = "test";
 
+    public MatchPhraseQueryIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Before
     public void setUp() throws Exception {
         super.setUp();
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/seqno/GlobalCheckpointSyncIT.java b/server/src/internalClusterTest/java/org/opensearch/index/seqno/GlobalCheckpointSyncIT.java
index ce7cb81dbd2df..9388d7344cf3f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/seqno/GlobalCheckpointSyncIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/seqno/GlobalCheckpointSyncIT.java
@@ -37,15 +37,15 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
 
@@ -82,7 +82,7 @@ public void testGlobalCheckpointSyncWithAsyncDurability() throws Exception {
 
         for (int j = 0; j < 10; j++) {
             final String id = Integer.toString(j);
-            client().prepareIndex("test").setId(id).setSource("{\"foo\": " + id + "}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(id).setSource("{\"foo\": " + id + "}", MediaTypeRegistry.JSON).get();
         }
 
         assertBusy(() -> {
@@ -194,7 +194,7 @@ private void runGlobalCheckpointSyncTest(
                 }
                 for (int j = 0; j < numberOfDocuments; j++) {
                     final String id = Integer.toString(index * numberOfDocuments + j);
-                    client().prepareIndex("test").setId(id).setSource("{\"foo\": " + id + "}", XContentType.JSON).get();
+                    client().prepareIndex("test").setId(id).setSource("{\"foo\": " + id + "}", MediaTypeRegistry.JSON).get();
                 }
                 try {
                     barrier.await();
@@ -251,7 +251,7 @@ public void testPersistGlobalCheckpoint() throws Exception {
         }
         int numDocs = randomIntBetween(1, 20);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
         }
         ensureGreen("test");
         assertBusy(() -> {
@@ -281,7 +281,7 @@ public void testPersistLocalCheckpoint() {
         logger.info("numDocs {}", numDocs);
         long maxSeqNo = 0;
         for (int i = 0; i < numDocs; i++) {
-            maxSeqNo = client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get().getSeqNo();
+            maxSeqNo = client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get().getSeqNo();
             logger.info("got {}", maxSeqNo);
         }
         for (IndicesService indicesService : internalCluster().getDataNodeInstances(IndicesService.class)) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseCreationIT.java b/server/src/internalClusterTest/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseCreationIT.java
index e1e969345d5ed..83dd409e750b0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseCreationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseCreationIT.java
@@ -38,8 +38,8 @@
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.nio.file.Path;
@@ -63,7 +63,7 @@ public void testCanRecoverFromStoreWithoutPeerRecoveryRetentionLease() throws Ex
          * primary that is recovering from store creates a lease for itself.
          */
 
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final Path[] nodeDataPaths = internalCluster().getInstance(NodeEnvironment.class, dataNode).nodeDataPaths();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/seqno/RetentionLeaseIT.java b/server/src/internalClusterTest/java/org/opensearch/index/seqno/RetentionLeaseIT.java
index ed6074b39c8a7..6163edada9f6e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/seqno/RetentionLeaseIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/seqno/RetentionLeaseIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.index.seqno;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -41,10 +40,11 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.plugins.Plugin;
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/shard/GlobalCheckpointListenersIT.java b/server/src/internalClusterTest/java/org/opensearch/index/shard/GlobalCheckpointListenersIT.java
index a2c5c0333bbfe..d60e852a82ca0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/shard/GlobalCheckpointListenersIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/shard/GlobalCheckpointListenersIT.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -88,7 +88,7 @@ public void accept(final long g, final Exception e) {
                 }
 
             }, null);
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
             assertBusy(() -> assertThat(globalCheckpoint.get(), equalTo((long) index)));
             // adding a listener expecting a lower global checkpoint should fire immediately
             final AtomicLong immediateGlobalCheckpint = new AtomicLong();
@@ -126,7 +126,7 @@ public void accept(final long g, final Exception e) {
             }
 
         }, null);
-        shard.close("closed", randomBoolean());
+        shard.close("closed", randomBoolean(), false);
         assertBusy(() -> assertTrue(invoked.get()));
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/shard/IndexShardIT.java b/server/src/internalClusterTest/java/org/opensearch/index/shard/IndexShardIT.java
index efc522a1f9741..44a900491d949 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/shard/IndexShardIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/shard/IndexShardIT.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.store.LockObtainFailedException;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
@@ -53,20 +52,23 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedRunnable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
@@ -78,19 +80,19 @@
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.InternalTranslogFactory;
 import org.opensearch.index.translog.TestTranslog;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.IndexSettingsModule;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.junit.Assert;
 
 import java.io.IOException;
@@ -114,7 +116,6 @@
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.randomAsciiLettersOfLength;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
@@ -127,13 +128,13 @@
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
-
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.either;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.randomAsciiLettersOfLength;
 
 public class IndexShardIT extends OpenSearchSingleNodeTestCase {
 
@@ -173,7 +174,7 @@ public void testLockTryingToDelete() throws Exception {
     public void testDurableFlagHasEffect() throws Exception {
         createIndex("test");
         ensureGreen();
-        client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
         IndicesService indicesService = getInstanceFromNode(IndicesService.class);
         IndexService test = indicesService.indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
@@ -193,7 +194,7 @@ public void testDurableFlagHasEffect() throws Exception {
         setDurability(shard, Translog.Durability.REQUEST);
         assertFalse(needsSync.test(translog));
         setDurability(shard, Translog.Durability.ASYNC);
-        client().prepareIndex("test").setId("2").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("2").setSource("{}", MediaTypeRegistry.JSON).get();
         assertTrue(needsSync.test(translog));
         setDurability(shard, Translog.Durability.REQUEST);
         client().prepareDelete("test", "1").get();
@@ -205,7 +206,7 @@ public void testDurableFlagHasEffect() throws Exception {
         setDurability(shard, Translog.Durability.REQUEST);
         assertNoFailures(
             client().prepareBulk()
-                .add(client().prepareIndex("test").setId("3").setSource("{}", XContentType.JSON))
+                .add(client().prepareIndex("test").setId("3").setSource("{}", MediaTypeRegistry.JSON))
                 .add(client().prepareDelete("test", "1"))
                 .get()
         );
@@ -214,7 +215,7 @@ public void testDurableFlagHasEffect() throws Exception {
         setDurability(shard, Translog.Durability.ASYNC);
         assertNoFailures(
             client().prepareBulk()
-                .add(client().prepareIndex("test").setId("4").setSource("{}", XContentType.JSON))
+                .add(client().prepareIndex("test").setId("4").setSource("{}", MediaTypeRegistry.JSON))
                 .add(client().prepareDelete("test", "3"))
                 .get()
         );
@@ -252,7 +253,7 @@ public void testIndexDirIsDeletedWhenShardRemoved() throws Exception {
         Settings idxSettings = Settings.builder().put(IndexMetadata.SETTING_DATA_PATH, idxPath).build();
         createIndex("test", idxSettings);
         ensureGreen("test");
-        client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).setRefreshPolicy(IMMEDIATE).get();
         SearchResponse response = client().prepareSearch("test").get();
         assertHitCount(response, 1L);
         client().admin().indices().prepareDelete("test").get();
@@ -268,7 +269,7 @@ public void testExpectedShardSizeIsPresent() throws InterruptedException {
                 .setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0))
         );
         for (int i = 0; i < 50; i++) {
-            client().prepareIndex("test").setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setSource("{}", MediaTypeRegistry.JSON).get();
         }
         ensureGreen("test");
         InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) getInstanceFromNode(ClusterInfoService.class);
@@ -368,14 +369,14 @@ public void testMaybeFlush() throws Exception {
             .get();
         client().prepareIndex("test")
             .setId("0")
-            .setSource("{}", XContentType.JSON)
+            .setSource("{}", MediaTypeRegistry.JSON)
             .setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE)
             .get();
         assertFalse(shard.shouldPeriodicallyFlush());
         shard.applyIndexOperationOnPrimary(
             Versions.MATCH_ANY,
             VersionType.INTERNAL,
-            new SourceToParse("test", "1", new BytesArray("{}"), XContentType.JSON),
+            new SourceToParse("test", "1", new BytesArray("{}"), MediaTypeRegistry.JSON),
             SequenceNumbers.UNASSIGNED_SEQ_NO,
             0,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -387,7 +388,7 @@ public void testMaybeFlush() throws Exception {
         assertThat(shard.flushStats().getTotal(), equalTo(0L));
         client().prepareIndex("test")
             .setId("2")
-            .setSource("{}", XContentType.JSON)
+            .setSource("{}", MediaTypeRegistry.JSON)
             .setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE)
             .get();
         assertThat(shard.getLastKnownGlobalCheckpoint(), equalTo(2L));
@@ -428,7 +429,7 @@ public void testMaybeFlush() throws Exception {
             final FlushStats flushStats = shard.flushStats();
             logger.info(
                 "--> translog stats [{}] gen [{}] commit_stats [{}] flush_stats [{}/{}]",
-                Strings.toString(translogStats),
+                Strings.toString(MediaTypeRegistry.JSON, translogStats),
                 translog.getGeneration().translogFileGeneration,
                 commitStats.getUserData(),
                 flushStats.getPeriodic(),
@@ -460,7 +461,7 @@ public void testMaybeRollTranslogGeneration() throws Exception {
             final Engine.IndexResult result = shard.applyIndexOperationOnPrimary(
                 Versions.MATCH_ANY,
                 VersionType.INTERNAL,
-                new SourceToParse("test", "1", new BytesArray("{}"), XContentType.JSON),
+                new SourceToParse("test", "1", new BytesArray("{}"), MediaTypeRegistry.JSON),
                 SequenceNumbers.UNASSIGNED_SEQ_NO,
                 0,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -496,7 +497,7 @@ public void testStressMaybeFlushOrRollTranslogGeneration() throws Exception {
         client().admin().indices().prepareUpdateSettings("test").setSettings(settings).get();
         client().prepareIndex("test")
             .setId("0")
-            .setSource("{}", XContentType.JSON)
+            .setSource("{}", MediaTypeRegistry.JSON)
             .setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE)
             .get();
         assertFalse(shard.shouldPeriodicallyFlush());
@@ -521,7 +522,7 @@ public void testStressMaybeFlushOrRollTranslogGeneration() throws Exception {
         final CheckedRunnable<Exception> check;
         if (flush) {
             final FlushStats initialStats = shard.flushStats();
-            client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
             check = () -> {
                 assertFalse(shard.shouldPeriodicallyFlush());
                 final FlushStats currentStats = shard.flushStats();
@@ -546,7 +547,7 @@ public void testStressMaybeFlushOrRollTranslogGeneration() throws Exception {
             };
         } else {
             final long generation = getTranslog(shard).currentFileGeneration();
-            client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
             check = () -> {
                 assertFalse(shard.shouldRollTranslogGeneration());
                 assertEquals(generation + 1, getTranslog(shard).currentFileGeneration());
@@ -567,7 +568,7 @@ public void testFlushStats() throws Exception {
         client().admin().indices().prepareUpdateSettings("test").setSettings(settings).get();
         final int numDocs = between(10, 100);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
         }
         // A flush stats may include the new total count but the old period count - assert eventually.
         assertBusy(() -> {
@@ -578,7 +579,7 @@ public void testFlushStats() throws Exception {
         settings = Settings.builder().put("index.translog.flush_threshold_size", (String) null).build();
         client().admin().indices().prepareUpdateSettings("test").setSettings(settings).get();
 
-        client().prepareIndex("test").setId(UUIDs.randomBase64UUID()).setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test").setId(UUIDs.randomBase64UUID()).setSource("{}", MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareFlush("test").setForce(randomBoolean()).setWaitIfOngoing(true).get();
         final FlushStats flushStats = client().admin().indices().prepareStats("test").clear().setFlush(true).get().getTotal().flush;
         assertThat(flushStats.getTotal(), greaterThan(flushStats.getPeriodic()));
@@ -590,12 +591,12 @@ public void testShardHasMemoryBufferOnTranslogRecover() throws Throwable {
         IndicesService indicesService = getInstanceFromNode(IndicesService.class);
         IndexService indexService = indicesService.indexService(resolveIndex("test"));
         IndexShard shard = indexService.getShardOrNull(0);
-        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).get();
         client().prepareDelete("test", "0").get();
-        client().prepareIndex("test").setId("1").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).setRefreshPolicy(IMMEDIATE).get();
 
         CheckedFunction<DirectoryReader, DirectoryReader, IOException> wrapper = directoryReader -> directoryReader;
-        shard.close("simon says", false);
+        shard.close("simon says", false, false);
         AtomicReference<IndexShard> shardRef = new AtomicReference<>();
         List<Exception> failures = new ArrayList<>();
         IndexingOperationListener listener = new IndexingOperationListener() {
@@ -626,14 +627,22 @@ public void postDelete(ShardId shardId, Engine.Delete delete, Engine.DeleteResul
                 }
             }
         };
-        final IndexShard newShard = newIndexShard(indexService, shard, wrapper, getInstanceFromNode(CircuitBreakerService.class), listener);
+        NodeEnvironment env = getInstanceFromNode(NodeEnvironment.class);
+        final IndexShard newShard = newIndexShard(
+            indexService,
+            shard,
+            wrapper,
+            getInstanceFromNode(CircuitBreakerService.class),
+            env.nodeId(),
+            listener
+        );
         shardRef.set(newShard);
         recoverShard(newShard);
 
         try {
             ExceptionsHelper.rethrowAndSuppress(failures);
         } finally {
-            newShard.close("just do it", randomBoolean());
+            newShard.close("just do it", randomBoolean(), false);
         }
     }
 
@@ -650,6 +659,7 @@ public static final IndexShard newIndexShard(
         final IndexShard shard,
         CheckedFunction<DirectoryReader, DirectoryReader, IOException> wrapper,
         final CircuitBreakerService cbs,
+        final String nodeId,
         final IndexingOperationListener... listeners
     ) throws IOException {
         ShardRouting initializingShardRouting = getInitializingShardRouting(shard.routingEntry());
@@ -673,7 +683,14 @@ public static final IndexShard newIndexShard(
             Arrays.asList(listeners),
             () -> {},
             RetentionLeaseSyncer.EMPTY,
-            cbs
+            cbs,
+            (indexSettings, shardRouting) -> new InternalTranslogFactory(),
+            SegmentReplicationCheckpointPublisher.EMPTY,
+            null,
+            null,
+            () -> IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+            nodeId,
+            null
         );
     }
 
@@ -704,7 +721,7 @@ public void testInvalidateIndicesRequestCacheWhenRollbackEngine() throws Excepti
         final SearchRequest countRequest = new SearchRequest("test").source(new SearchSourceBuilder().size(0));
         final long numDocs = between(10, 20);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
             if (randomBoolean()) {
                 shard.refresh("test");
             }
@@ -726,7 +743,7 @@ public void testInvalidateIndicesRequestCacheWhenRollbackEngine() throws Excepti
 
         final long moreDocs = between(10, 20);
         for (int i = 0; i < moreDocs; i++) {
-            client().prepareIndex("test").setId(Long.toString(i + numDocs)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Long.toString(i + numDocs)).setSource("{}", MediaTypeRegistry.JSON).get();
             if (randomBoolean()) {
                 shard.refresh("test");
             }
@@ -757,7 +774,7 @@ public void testShardChangesWithDefaultDocType() throws Exception {
         int numOps = between(1, 10);
         for (int i = 0; i < numOps; i++) {
             if (randomBoolean()) {
-                client().prepareIndex("index").setId(randomFrom("1", "2")).setSource("{}", XContentType.JSON).get();
+                client().prepareIndex("index").setId(randomFrom("1", "2")).setSource("{}", MediaTypeRegistry.JSON).get();
             } else {
                 client().prepareDelete("index", randomFrom("1", "2")).get();
             }
@@ -820,7 +837,7 @@ public void testLimitNumberOfRetainedTranslogFiles() throws Exception {
             }
         };
         for (int i = 0; i < 100; i++) {
-            client().prepareIndex(indexName).setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex(indexName).setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
             if (randomInt(100) < 10) {
                 client().admin().indices().prepareFlush(indexName).setWaitIfOngoing(true).get();
                 checkTranslog.run();
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandIT.java b/server/src/internalClusterTest/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandIT.java
index 2dc241e278768..b431079476624 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandIT.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index.shard;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import joptsimple.OptionParser;
 import joptsimple.OptionSet;
 import org.apache.lucene.index.IndexWriter;
@@ -41,9 +41,7 @@
 import org.apache.lucene.store.Lock;
 import org.apache.lucene.store.LockObtainFailedException;
 import org.apache.lucene.store.NativeFSLockFactory;
-
 import org.opensearch.ExceptionsHelper;
-
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplanation;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
@@ -66,15 +64,16 @@
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.gateway.GatewayMetaState;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.translog.TestTranslog;
@@ -83,9 +82,9 @@
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.CorruptionUtils;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.engine.MockEngineSupport;
 import org.opensearch.test.transport.MockTransportService;
 
@@ -105,11 +104,10 @@
 import java.util.stream.StreamSupport;
 
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.FS;
-import static org.opensearch.common.util.CollectionUtils.iterableAsArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.iterableAsArrayList;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -137,7 +135,7 @@ public void testCorruptIndex() throws Exception {
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
                     .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "-1")
                     .put(MockEngineSupport.DISABLE_FLUSH_ON_CLOSE.getKey(), true)
                     .put(IndexSettings.INDEX_CHECK_ON_STARTUP.getKey(), "checksum")
@@ -235,10 +233,10 @@ public Settings onNodeStopped(String nodeName) throws Exception {
         String nodeId = null;
         final ClusterState state = client().admin().cluster().prepareState().get().getState();
         final DiscoveryNodes nodes = state.nodes();
-        for (ObjectObjectCursor<String, DiscoveryNode> cursor : nodes.getNodes()) {
-            final String name = cursor.value.getName();
+        for (final Map.Entry<String, DiscoveryNode> cursor : nodes.getNodes().entrySet()) {
+            final String name = cursor.getValue().getName();
             if (name.equals(node)) {
-                nodeId = cursor.key;
+                nodeId = cursor.getKey();
                 break;
             }
         }
@@ -423,10 +421,10 @@ public Settings onNodeStopped(String nodeName) throws Exception {
         String primaryNodeId = null;
         final ClusterState state = client().admin().cluster().prepareState().get().getState();
         final DiscoveryNodes nodes = state.nodes();
-        for (ObjectObjectCursor<String, DiscoveryNode> cursor : nodes.getNodes()) {
-            final String name = cursor.value.getName();
+        for (final Map.Entry<String, DiscoveryNode> cursor : nodes.getNodes().entrySet()) {
+            final String name = cursor.getValue().getName();
             if (name.equals(node1)) {
-                primaryNodeId = cursor.key;
+                primaryNodeId = cursor.getKey();
                 break;
             }
         }
@@ -497,7 +495,7 @@ public Settings onNodeStopped(String nodeName) throws Exception {
     }
 
     public void testCorruptTranslogTruncationOfReplica() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
 
         final String node1 = internalCluster().startDataOnlyNode();
         final String node2 = internalCluster().startDataOnlyNode();
@@ -630,8 +628,8 @@ public void testResolvePath() throws Exception {
         final Map<String, String> nodeNameToNodeId = new HashMap<>();
         final ClusterState state = client().admin().cluster().prepareState().get().getState();
         final DiscoveryNodes nodes = state.nodes();
-        for (ObjectObjectCursor<String, DiscoveryNode> cursor : nodes.getNodes()) {
-            nodeNameToNodeId.put(cursor.value.getName(), cursor.key);
+        for (final Map.Entry<String, DiscoveryNode> cursor : nodes.getNodes().entrySet()) {
+            nodeNameToNodeId.put(cursor.getValue().getName(), cursor.getKey());
         }
 
         final GroupShardsIterator shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(new String[] { indexName }, false);
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/shard/SearchIdleIT.java b/server/src/internalClusterTest/java/org/opensearch/index/shard/SearchIdleIT.java
index 9382960b906e3..43d86b232de77 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/shard/SearchIdleIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/shard/SearchIdleIT.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -102,7 +102,7 @@ private void runTestAutomaticRefresh(final IntToLongFunction count) throws Inter
         int numDocs = scaledRandomIntBetween(25, 100);
         totalNumDocs.set(numDocs);
         CountDownLatch indexingDone = new CountDownLatch(numDocs);
-        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).get();
         indexingDone.countDown(); // one doc is indexed above blocking
         IndexShard shard = indexService.getShard(0);
         boolean hasRefreshed = shard.scheduledRefresh();
@@ -135,7 +135,7 @@ private void runTestAutomaticRefresh(final IntToLongFunction count) throws Inter
         for (int i = 1; i < numDocs; i++) {
             client().prepareIndex("test")
                 .setId("" + i)
-                .setSource("{\"foo\" : \"bar\"}", XContentType.JSON)
+                .setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON)
                 .execute(new ActionListener<IndexResponse>() {
                     @Override
                     public void onResponse(IndexResponse indexResponse) {
@@ -159,7 +159,7 @@ public void testPendingRefreshWithIntervalChange() throws Exception {
         IndexService indexService = createIndex("test", builder.build());
         assertFalse(indexService.getIndexSettings().isExplicitRefresh());
         ensureGreen();
-        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("0").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).get();
         IndexShard shard = indexService.getShard(0);
         assertFalse(shard.scheduledRefresh());
         assertTrue(shard.isSearchIdle());
@@ -167,7 +167,7 @@ public void testPendingRefreshWithIntervalChange() throws Exception {
         client().admin().indices().prepareRefresh().execute(ActionListener.wrap(refreshLatch::countDown));// async on purpose to make sure
                                                                                                           // it happens concurrently
         assertHitCount(client().prepareSearch().get(), 1);
-        client().prepareIndex("test").setId("1").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).get();
         assertFalse(shard.scheduledRefresh());
         assertTrue(shard.hasRefreshPending());
 
@@ -186,7 +186,7 @@ public void testPendingRefreshWithIntervalChange() throws Exception {
         // We need to ensure a `scheduledRefresh` triggered by the internal refresh setting update is executed before we index a new doc;
         // otherwise, it will compete to call `Engine#maybeRefresh` with the `scheduledRefresh` that we are going to verify.
         ensureNoPendingScheduledRefresh(indexService.getThreadPool());
-        client().prepareIndex("test").setId("2").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("2").setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON).get();
         assertTrue(shard.scheduledRefresh());
         assertFalse(shard.hasRefreshPending());
         assertTrue(shard.isSearchIdle());
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedFileIT.java b/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedFileIT.java
index 3a5e21fc8ef65..8291fef5d177b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedFileIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedFileIT.java
@@ -31,15 +31,14 @@
 
 package org.opensearch.index.store;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.index.CheckIndex;
 import org.apache.lucene.index.SegmentCommitInfo;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.FSDirectory;
 import org.apache.lucene.util.BytesRef;
-
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -48,6 +47,7 @@
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.health.ClusterHealthStatus;
@@ -60,34 +60,35 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.indices.recovery.FileChunkRequest;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
-import org.opensearch.indices.recovery.RecoveryFileChunkRequest;
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.snapshots.SnapshotState;
 import org.opensearch.test.CorruptionUtils;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.MockIndexEventListener;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.store.MockFSIndexStore;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -108,13 +109,13 @@
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
 
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.FS;
-import static org.opensearch.common.util.CollectionUtils.iterableAsArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.iterableAsArrayList;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
-
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
@@ -166,7 +167,7 @@ public void testCorruptFileAndRecover() throws ExecutionException, InterruptedEx
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "1")
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
                     // no checkindex - we corrupt shards on purpose
                     .put(MockFSIndexStore.INDEX_CHECK_INDEX_ON_CLOSE_SETTING.getKey(), false)
                     // no translog based flush - it might change the .liv / segments.N files
@@ -285,7 +286,7 @@ public void testCorruptPrimaryNoReplica() throws ExecutionException, Interrupted
             prepareCreate("test").setSettings(
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
                     .put(MockFSIndexStore.INDEX_CHECK_INDEX_ON_CLOSE_SETTING.getKey(), false) // no checkindex - we corrupt shards on
                                                                                               // purpose
                     // no translog based flush - it might change the .liv / segments.N files
@@ -397,7 +398,7 @@ public void testCorruptionOnNetworkLayerFinalizingRecovery() throws ExecutionExc
                 internalCluster().getInstance(TransportService.class, unluckyNode.getNode().getName()),
                 (connection, requestId, action, request, options) -> {
                     if (corrupt.get() && action.equals(PeerRecoveryTargetService.Actions.FILE_CHUNK)) {
-                        RecoveryFileChunkRequest req = (RecoveryFileChunkRequest) request;
+                        FileChunkRequest req = (FileChunkRequest) request;
                         byte[] array = BytesRef.deepCopyOf(req.content().toBytesRef()).bytes;
                         int i = randomIntBetween(0, req.content().length() - 1);
                         array[i] = (byte) ~array[i]; // flip one byte in the content
@@ -474,11 +475,11 @@ public void testCorruptionOnNetworkLayer() throws ExecutionException, Interrupte
                 internalCluster().getInstance(TransportService.class, unluckyNode.getNode().getName()),
                 (connection, requestId, action, request, options) -> {
                     if (action.equals(PeerRecoveryTargetService.Actions.FILE_CHUNK)) {
-                        RecoveryFileChunkRequest req = (RecoveryFileChunkRequest) request;
+                        FileChunkRequest req = (FileChunkRequest) request;
                         if (truncate && req.length() > 1) {
                             BytesRef bytesRef = req.content().toBytesRef();
                             BytesArray array = new BytesArray(bytesRef.bytes, bytesRef.offset, (int) req.length() - 1);
-                            request = new RecoveryFileChunkRequest(
+                            request = new FileChunkRequest(
                                 req.recoveryId(),
                                 req.requestSeqNo(),
                                 req.shardId(),
@@ -551,7 +552,7 @@ public void testCorruptFileThenSnapshotAndRestore() throws ExecutionException, I
             prepareCreate("test").setSettings(
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0") // no replicas for this test
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
                     // no checkindex - we corrupt shards on purpose
                     .put(MockFSIndexStore.INDEX_CHECK_INDEX_ON_CLOSE_SETTING.getKey(), false)
                     // no translog based flush - it might change the .liv / segments.N files
@@ -623,7 +624,7 @@ public void testReplicaCorruption() throws Exception {
             prepareCreate("test").setSettings(
                 Settings.builder()
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, cluster().numDataNodes() - 1)
-                    .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+                    .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
                     .put(MockFSIndexStore.INDEX_CHECK_INDEX_ON_CLOSE_SETTING.getKey(), false) // no checkindex - we corrupt shards on
                                                                                               // purpose
                     .put(IndexSettings.INDEX_TRANSLOG_FLUSH_THRESHOLD_SIZE_SETTING.getKey(), new ByteSizeValue(1, ByteSizeUnit.PB)) // no
@@ -671,9 +672,9 @@ public void testReplicaCorruption() throws Exception {
 
         final IndicesShardStoresResponse stores = client().admin().indices().prepareShardStores(index.getName()).get();
 
-        for (IntObjectCursor<List<IndicesShardStoresResponse.StoreStatus>> shards : stores.getStoreStatuses().get(index.getName())) {
-            for (IndicesShardStoresResponse.StoreStatus store : shards.value) {
-                final ShardId shardId = new ShardId(index, shards.key);
+        for (var shards : stores.getStoreStatuses().get(index.getName()).entrySet()) {
+            for (IndicesShardStoresResponse.StoreStatus store : shards.getValue()) {
+                final ShardId shardId = new ShardId(index, shards.getKey());
                 if (store.getAllocationStatus().equals(IndicesShardStoresResponse.StoreStatus.AllocationStatus.UNUSED)) {
                     for (Path path : findFilesToCorruptOnNode(store.getNode().getName(), shardId)) {
                         try (OutputStream os = Files.newOutputStream(path)) {
@@ -698,6 +699,104 @@ public void testReplicaCorruption() throws Exception {
         ensureGreen(TimeValue.timeValueSeconds(60));
     }
 
+    public void testPrimaryCorruptionDuringReplicationDoesNotFailReplicaShard() throws Exception {
+        internalCluster().ensureAtLeastNumDataNodes(2);
+        final NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats().get();
+        final List<NodeStats> dataNodeStats = nodeStats.getNodes()
+            .stream()
+            .filter(stat -> stat.getNode().isDataNode())
+            .collect(Collectors.toUnmodifiableList());
+        MatcherAssert.assertThat(dataNodeStats.size(), greaterThanOrEqualTo(2));
+
+        final NodeStats primaryNode = dataNodeStats.get(0);
+        final NodeStats replicaNode = dataNodeStats.get(1);
+        assertAcked(
+            prepareCreate("test").setSettings(
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                    .put("index.routing.allocation.include._name", primaryNode.getNode().getName())
+                    .put(EnableAllocationDecider.INDEX_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), EnableAllocationDecider.Rebalance.NONE)
+                    .put("index.allocation.max_retries", Integer.MAX_VALUE) // keep on retrying
+
+            )
+        );
+        ensureGreen();
+
+        // Add custom send behavior between primary and replica that will
+        // count down a latch to indicate that a replication operation is
+        // currently in flight, and then block on a second latch that will
+        // be released once the primary shard has been corrupted.
+        final CountDownLatch indexingInFlight = new CountDownLatch(1);
+        final CountDownLatch corruptionHasHappened = new CountDownLatch(1);
+        final MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            primaryNode.getNode().getName()
+        ));
+        mockTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, replicaNode.getNode().getName()),
+            (connection, requestId, action, request, options) -> {
+                if (request instanceof TransportReplicationAction.ConcreteShardRequest) {
+                    indexingInFlight.countDown();
+                    try {
+                        corruptionHasHappened.await();
+                    } catch (InterruptedException e) {
+                        logger.info("Interrupted while waiting for corruption");
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+
+        // Configure the modified data node as a replica
+        final Settings build = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "1")
+            .put("index.routing.allocation.include._name", primaryNode.getNode().getName() + "," + replicaNode.getNode().getName())
+            .build();
+        client().admin().indices().prepareUpdateSettings("test").setSettings(build).get();
+        client().admin().cluster().prepareReroute().get();
+        ensureGreen();
+
+        // Create a snapshot repository. This repo is used to take a snapshot after
+        // corrupting a file, which causes the node to notice the corrupt data and
+        // close the shard.
+        assertAcked(
+            client().admin()
+                .cluster()
+                .preparePutRepository("test-repo")
+                .setType("fs")
+                .setSettings(
+                    Settings.builder()
+                        .put("location", randomRepoPath().toAbsolutePath())
+                        .put("compress", randomBoolean())
+                        .put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES)
+                )
+        );
+
+        client().prepareIndex("test").setSource("field", "value").execute();
+        indexingInFlight.await();
+
+        // Corrupt a file on the primary then take a snapshot. Snapshot should
+        // finish in the PARTIAL state since the corrupted file will cause a checksum
+        // validation failure.
+        final ShardRouting corruptedShardRouting = corruptRandomPrimaryFile();
+        logger.info("--> {} corrupted", corruptedShardRouting);
+        final CreateSnapshotResponse createSnapshotResponse = client().admin()
+            .cluster()
+            .prepareCreateSnapshot("test-repo", "test-snap")
+            .setWaitForCompletion(true)
+            .setIndices("test")
+            .get();
+        final SnapshotState snapshotState = createSnapshotResponse.getSnapshotInfo().state();
+        MatcherAssert.assertThat("Expect file corruption to cause PARTIAL snapshot state", snapshotState, equalTo(SnapshotState.PARTIAL));
+
+        // Unblock the blocked indexing thread now that corruption on the primary has been confirmed
+        corruptionHasHappened.countDown();
+
+        // Assert the cluster returns to green status because the replica will be promoted to primary
+        ensureGreen();
+    }
+
     private int numShards(String... index) {
         ClusterState state = client().admin().cluster().prepareState().get().getState();
         GroupShardsIterator shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(index, false);
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedTranslogIT.java b/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedTranslogIT.java
index 1dd0f6a3d664e..f749593de13d2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedTranslogIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/store/CorruptedTranslogIT.java
@@ -38,16 +38,16 @@
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.translog.TestTranslog;
 import org.opensearch.index.translog.TranslogCorruptedException;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.engine.MockEngineSupport;
 import org.opensearch.test.transport.MockTransportService;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/store/ExceptionRetryIT.java b/server/src/internalClusterTest/java/org/opensearch/index/store/ExceptionRetryIT.java
index 3e2091b2065e5..1e3c22c85b0b2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/store/ExceptionRetryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/store/ExceptionRetryIT.java
@@ -44,7 +44,7 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.client.Client;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.SegmentsStats;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.SearchHit;
diff --git a/server/src/internalClusterTest/java/org/opensearch/index/suggest/stats/SuggestStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/index/suggest/stats/SuggestStatsIT.java
index 9940b1eb13a52..6332b1b97426f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/index/suggest/stats/SuggestStatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/index/suggest/stats/SuggestStatsIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.index.suggest.stats;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
@@ -42,17 +44,22 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.search.stats.SearchStats;
 import org.opensearch.search.suggest.SuggestBuilder;
 import org.opensearch.search.suggest.phrase.PhraseSuggestionBuilder;
 import org.opensearch.search.suggest.term.TermSuggestionBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.hamcrest.Matchers.equalTo;
@@ -61,7 +68,25 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 @OpenSearchIntegTestCase.ClusterScope(minNumDataNodes = 2)
-public class SuggestStatsIT extends OpenSearchIntegTestCase {
+public class SuggestStatsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SuggestStatsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected int numberOfReplicas() {
         return 0;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indexing/IndexActionIT.java b/server/src/internalClusterTest/java/org/opensearch/indexing/IndexActionIT.java
index 45fbb2651a96d..73d6d9aff7b72 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indexing/IndexActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indexing/IndexActionIT.java
@@ -288,10 +288,9 @@ public void testInvalidIndexName() {
     }
 
     public void testDocumentWithBlankFieldName() {
-        MapperParsingException e = expectThrows(
-            MapperParsingException.class,
-            () -> { client().prepareIndex("test").setId("1").setSource("", "value1_2").execute().actionGet(); }
-        );
+        MapperParsingException e = expectThrows(MapperParsingException.class, () -> {
+            client().prepareIndex("test").setId("1").setSource("", "value1_2").execute().actionGet();
+        });
         assertThat(e.getMessage(), containsString("failed to parse"));
         assertThat(e.getRootCause().getMessage(), containsString("field name cannot be an empty string"));
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/DateMathIndexExpressionsIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/DateMathIndexExpressionsIntegrationIT.java
index 7236c32697384..2f348e5d6218d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/DateMathIndexExpressionsIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/DateMathIndexExpressionsIntegrationIT.java
@@ -41,9 +41,8 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
 import org.joda.time.format.DateTimeFormat;
@@ -71,9 +70,9 @@ public void testIndexNameDateMathExpressions() {
         String dateMathExp1 = "<.marvel-{now/d}>";
         String dateMathExp2 = "<.marvel-{now/d-1d}>";
         String dateMathExp3 = "<.marvel-{now/d-2d}>";
-        client().prepareIndex(dateMathExp1).setId("1").setSource("{}", XContentType.JSON).get();
-        client().prepareIndex(dateMathExp2).setId("2").setSource("{}", XContentType.JSON).get();
-        client().prepareIndex(dateMathExp3).setId("3").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp1).setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex(dateMathExp2).setId("2").setSource("{}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex(dateMathExp3).setId("3").setSource("{}", MediaTypeRegistry.JSON).get();
         refresh();
 
         SearchResponse searchResponse = client().prepareSearch(dateMathExp1, dateMathExp2, dateMathExp3).get();
@@ -131,9 +130,9 @@ public void testAutoCreateIndexWithDateMathExpression() throws Exception {
         String dateMathExp1 = "<.marvel-{now/d}>";
         String dateMathExp2 = "<.marvel-{now/d-1d}>";
         String dateMathExp3 = "<.marvel-{now/d-2d}>";
-        client().prepareIndex(dateMathExp1).setId("1").setSource("{}", XContentType.JSON).get();
-        client().prepareIndex(dateMathExp2).setId("2").setSource("{}", XContentType.JSON).get();
-        client().prepareIndex(dateMathExp3).setId("3").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp1).setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex(dateMathExp2).setId("2").setSource("{}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex(dateMathExp3).setId("3").setSource("{}", MediaTypeRegistry.JSON).get();
         refresh();
 
         SearchResponse searchResponse = client().prepareSearch(dateMathExp1, dateMathExp2, dateMathExp3).get();
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/IndexingMemoryControllerIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/IndexingMemoryControllerIT.java
index 0d3c685ab0327..c842ee8564041 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/IndexingMemoryControllerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/IndexingMemoryControllerIT.java
@@ -81,30 +81,29 @@ EngineConfig engineConfigWithLargerIndexingMemory(EngineConfig config) {
                 .put("indices.memory.index_buffer_size", "10mb")
                 .build();
             IndexSettings indexSettings = new IndexSettings(config.getIndexSettings().getIndexMetadata(), settings);
-            return new EngineConfig(
-                config.getShardId(),
-                config.getThreadPool(),
-                indexSettings,
-                config.getWarmer(),
-                config.getStore(),
-                config.getMergePolicy(),
-                config.getAnalyzer(),
-                config.getSimilarity(),
-                new CodecService(null, LogManager.getLogger(IndexingMemoryControllerIT.class)),
-                config.getEventListener(),
-                config.getQueryCache(),
-                config.getQueryCachingPolicy(),
-                config.getTranslogConfig(),
-                config.getFlushMergesAfter(),
-                config.getExternalRefreshListener(),
-                config.getInternalRefreshListener(),
-                config.getIndexSort(),
-                config.getCircuitBreakerService(),
-                config.getGlobalCheckpointSupplier(),
-                config.retentionLeasesSupplier(),
-                config.getPrimaryTermSupplier(),
-                config.getTombstoneDocSupplier()
-            );
+            return new EngineConfig.Builder().shardId(config.getShardId())
+                .threadPool(config.getThreadPool())
+                .indexSettings(indexSettings)
+                .warmer(config.getWarmer())
+                .store(config.getStore())
+                .mergePolicy(config.getMergePolicy())
+                .analyzer(config.getAnalyzer())
+                .similarity(config.getSimilarity())
+                .codecService(new CodecService(null, indexSettings, LogManager.getLogger(IndexingMemoryControllerIT.class)))
+                .eventListener(config.getEventListener())
+                .queryCache(config.getQueryCache())
+                .queryCachingPolicy(config.getQueryCachingPolicy())
+                .translogConfig(config.getTranslogConfig())
+                .flushMergesAfter(config.getFlushMergesAfter())
+                .externalRefreshListener(config.getExternalRefreshListener())
+                .internalRefreshListener(config.getInternalRefreshListener())
+                .indexSort(config.getIndexSort())
+                .circuitBreakerService(config.getCircuitBreakerService())
+                .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+                .retentionLeasesSupplier(config.retentionLeasesSupplier())
+                .primaryTermSupplier(config.getPrimaryTermSupplier())
+                .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+                .build();
         }
 
         @Override
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesLifecycleListenerIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesLifecycleListenerIT.java
index 72f28e94528ba..f40c1b9ec2362 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesLifecycleListenerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesLifecycleListenerIT.java
@@ -44,19 +44,18 @@
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.test.MockIndexEventListener;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.MockIndexEventListener;
-
 import org.hamcrest.Matchers;
 
 import java.util.Arrays;
@@ -131,7 +130,7 @@ public void beforeIndexCreated(Index index, Settings indexSettings) {
         } catch (Exception e) {
             assertTrue(e.getMessage().contains("failing on purpose"));
             ClusterStateResponse resp = client().admin().cluster().prepareState().get();
-            assertFalse(resp.getState().routingTable().indicesRouting().keys().contains("failed"));
+            assertFalse(resp.getState().routingTable().indicesRouting().keySet().contains("failed"));
         }
     }
 
@@ -181,7 +180,7 @@ public void testIndexStateShardChanged() throws Throwable {
         } catch (OpenSearchException e) {
             assertTrue(e.getMessage().contains("failing on purpose"));
             ClusterStateResponse resp = client().admin().cluster().prepareState().get();
-            assertFalse(resp.getState().routingTable().indicesRouting().keys().contains("failed"));
+            assertFalse(resp.getState().routingTable().indicesRouting().keySet().contains("failed"));
         }
 
         // create an index
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesOptionsIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesOptionsIntegrationIT.java
index 3432cc967bf22..06d2d2a90de87 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesOptionsIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesOptionsIntegrationIT.java
@@ -34,10 +34,8 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequestBuilder;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequestBuilder;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistRequestBuilder;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequestBuilder;
 import org.opensearch.action.admin.indices.cache.clear.ClearIndicesCacheRequestBuilder;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsRequestBuilder;
 import org.opensearch.action.admin.indices.flush.FlushRequestBuilder;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequestBuilder;
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsRequestBuilder;
@@ -54,14 +52,14 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -98,8 +96,6 @@ public void testSpecifiedIndexUnavailableMultipleIndices() throws Exception {
         verify(forceMerge("test1", "test2"), true);
         verify(refreshBuilder("test1", "test2"), true);
         verify(validateQuery("test1", "test2"), true);
-        verify(aliasExists("test1", "test2"), true);
-        verify(typesExists("test1", "test2"), true);
         verify(getAliases("test1", "test2"), true);
         verify(getFieldMapping("test1", "test2"), true);
         verify(getMapping("test1", "test2"), true);
@@ -115,8 +111,6 @@ public void testSpecifiedIndexUnavailableMultipleIndices() throws Exception {
         verify(forceMerge("test1", "test2").setIndicesOptions(options), true);
         verify(refreshBuilder("test1", "test2").setIndicesOptions(options), true);
         verify(validateQuery("test1", "test2").setIndicesOptions(options), true);
-        verify(aliasExists("test1", "test2").setIndicesOptions(options), true);
-        verify(typesExists("test1", "test2").setIndicesOptions(options), true);
         verify(getAliases("test1", "test2").setIndicesOptions(options), true);
         verify(getFieldMapping("test1", "test2").setIndicesOptions(options), true);
         verify(getMapping("test1", "test2").setIndicesOptions(options), true);
@@ -132,8 +126,6 @@ public void testSpecifiedIndexUnavailableMultipleIndices() throws Exception {
         verify(forceMerge("test1", "test2").setIndicesOptions(options), false);
         verify(refreshBuilder("test1", "test2").setIndicesOptions(options), false);
         verify(validateQuery("test1", "test2").setIndicesOptions(options), false);
-        verify(aliasExists("test1", "test2").setIndicesOptions(options), false);
-        verify(typesExists("test1", "test2").setIndicesOptions(options), false);
         verify(getAliases("test1", "test2").setIndicesOptions(options), false);
         verify(getFieldMapping("test1", "test2").setIndicesOptions(options), false);
         verify(getMapping("test1", "test2").setIndicesOptions(options), false);
@@ -150,8 +142,6 @@ public void testSpecifiedIndexUnavailableMultipleIndices() throws Exception {
         verify(forceMerge("test1", "test2").setIndicesOptions(options), false);
         verify(refreshBuilder("test1", "test2").setIndicesOptions(options), false);
         verify(validateQuery("test1", "test2").setIndicesOptions(options), false);
-        verify(aliasExists("test1", "test2").setIndicesOptions(options), false);
-        verify(typesExists("test1", "test2").setIndicesOptions(options), false);
         verify(getAliases("test1", "test2").setIndicesOptions(options), false);
         verify(getFieldMapping("test1", "test2").setIndicesOptions(options), false);
         verify(getMapping("test1", "test2").setIndicesOptions(options), false);
@@ -177,8 +167,6 @@ public void testSpecifiedIndexUnavailableSingleIndexThatIsClosed() throws Except
         verify(forceMerge("test1").setIndicesOptions(options), true);
         verify(refreshBuilder("test1").setIndicesOptions(options), true);
         verify(validateQuery("test1").setIndicesOptions(options), true);
-        verify(aliasExists("test1").setIndicesOptions(options), true);
-        verify(typesExists("test1").setIndicesOptions(options), true);
         verify(getAliases("test1").setIndicesOptions(options), true);
         verify(getFieldMapping("test1").setIndicesOptions(options), true);
         verify(getMapping("test1").setIndicesOptions(options), true);
@@ -200,8 +188,6 @@ public void testSpecifiedIndexUnavailableSingleIndexThatIsClosed() throws Except
         verify(forceMerge("test1").setIndicesOptions(options), false);
         verify(refreshBuilder("test1").setIndicesOptions(options), false);
         verify(validateQuery("test1").setIndicesOptions(options), false);
-        verify(aliasExists("test1").setIndicesOptions(options), false);
-        verify(typesExists("test1").setIndicesOptions(options), false);
         verify(getAliases("test1").setIndicesOptions(options), false);
         verify(getFieldMapping("test1").setIndicesOptions(options), false);
         verify(getMapping("test1").setIndicesOptions(options), false);
@@ -220,8 +206,6 @@ public void testSpecifiedIndexUnavailableSingleIndexThatIsClosed() throws Except
         verify(forceMerge("test1").setIndicesOptions(options), false);
         verify(refreshBuilder("test1").setIndicesOptions(options), false);
         verify(validateQuery("test1").setIndicesOptions(options), false);
-        verify(aliasExists("test1").setIndicesOptions(options), false);
-        verify(typesExists("test1").setIndicesOptions(options), false);
         verify(getAliases("test1").setIndicesOptions(options), false);
         verify(getFieldMapping("test1").setIndicesOptions(options), false);
         verify(getMapping("test1").setIndicesOptions(options), false);
@@ -239,8 +223,6 @@ public void testSpecifiedIndexUnavailableSingleIndex() throws Exception {
         verify(forceMerge("test1").setIndicesOptions(options), true);
         verify(refreshBuilder("test1").setIndicesOptions(options), true);
         verify(validateQuery("test1").setIndicesOptions(options), true);
-        verify(aliasExists("test1").setIndicesOptions(options), true);
-        verify(typesExists("test1").setIndicesOptions(options), true);
         verify(getAliases("test1").setIndicesOptions(options), true);
         verify(getFieldMapping("test1").setIndicesOptions(options), true);
         verify(getMapping("test1").setIndicesOptions(options), true);
@@ -262,8 +244,6 @@ public void testSpecifiedIndexUnavailableSingleIndex() throws Exception {
         verify(forceMerge("test1").setIndicesOptions(options), false);
         verify(refreshBuilder("test1").setIndicesOptions(options), false);
         verify(validateQuery("test1").setIndicesOptions(options), false);
-        verify(aliasExists("test1").setIndicesOptions(options), false);
-        verify(typesExists("test1").setIndicesOptions(options), false);
         verify(getAliases("test1").setIndicesOptions(options), false);
         verify(getFieldMapping("test1").setIndicesOptions(options), false);
         verify(getMapping("test1").setIndicesOptions(options), false);
@@ -281,8 +261,6 @@ public void testSpecifiedIndexUnavailableSingleIndex() throws Exception {
         verify(forceMerge("test1").setIndicesOptions(options), false);
         verify(refreshBuilder("test1").setIndicesOptions(options), false);
         verify(validateQuery("test1").setIndicesOptions(options), false);
-        verify(aliasExists("test1").setIndicesOptions(options), false);
-        verify(typesExists("test1").setIndicesOptions(options), false);
         verify(getAliases("test1").setIndicesOptions(options), false);
         verify(getFieldMapping("test1").setIndicesOptions(options), false);
         verify(getMapping("test1").setIndicesOptions(options), false);
@@ -335,8 +313,6 @@ public void testWildcardBehaviour() throws Exception {
         verify(forceMerge(indices), false);
         verify(refreshBuilder(indices), false);
         verify(validateQuery(indices), true);
-        verify(aliasExists(indices), false);
-        verify(typesExists(indices), false);
         verify(getAliases(indices), false);
         verify(getFieldMapping(indices), false);
         verify(getMapping(indices), false);
@@ -353,8 +329,6 @@ public void testWildcardBehaviour() throws Exception {
         verify(forceMerge(indices).setIndicesOptions(options), false);
         verify(refreshBuilder(indices).setIndicesOptions(options), false);
         verify(validateQuery(indices).setIndicesOptions(options), false);
-        verify(aliasExists(indices).setIndicesOptions(options), false);
-        verify(typesExists(indices).setIndicesOptions(options), false);
         verify(getAliases(indices).setIndicesOptions(options), false);
         verify(getFieldMapping(indices).setIndicesOptions(options), false);
         verify(getMapping(indices).setIndicesOptions(options), false);
@@ -374,8 +348,6 @@ public void testWildcardBehaviour() throws Exception {
         verify(forceMerge(indices), false);
         verify(refreshBuilder(indices), false);
         verify(validateQuery(indices), false);
-        verify(aliasExists(indices), false);
-        verify(typesExists(indices), false);
         verify(getAliases(indices), false);
         verify(getFieldMapping(indices), false);
         verify(getMapping(indices), false);
@@ -392,8 +364,6 @@ public void testWildcardBehaviour() throws Exception {
         verify(forceMerge(indices), false);
         verify(refreshBuilder(indices), false);
         verify(validateQuery(indices), true);
-        verify(aliasExists(indices), false);
-        verify(typesExists(indices), false);
         verify(getAliases(indices), false);
         verify(getFieldMapping(indices), false);
         verify(getMapping(indices), false);
@@ -410,8 +380,6 @@ public void testWildcardBehaviour() throws Exception {
         verify(forceMerge(indices).setIndicesOptions(options), false);
         verify(refreshBuilder(indices).setIndicesOptions(options), false);
         verify(validateQuery(indices).setIndicesOptions(options), false);
-        verify(aliasExists(indices).setIndicesOptions(options), false);
-        verify(typesExists(indices).setIndicesOptions(options), false);
         verify(getAliases(indices).setIndicesOptions(options), false);
         verify(getFieldMapping(indices).setIndicesOptions(options), false);
         verify(getMapping(indices).setIndicesOptions(options), false);
@@ -573,25 +541,23 @@ public void testDeleteIndexWildcard() throws Exception {
     public void testPutAlias() throws Exception {
         createIndex("foobar");
         verify(client().admin().indices().prepareAliases().addAlias("foobar", "foobar_alias"), false);
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("foobar").get().exists(), equalTo(true));
-
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("foobar").get().getAliases().isEmpty());
     }
 
     public void testPutAliasWildcard() throws Exception {
         createIndex("foo", "foobar", "bar", "barbaz");
 
         verify(client().admin().indices().prepareAliases().addAlias("foo*", "foobar_alias"), false);
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("foo").get().exists(), equalTo(true));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("foobar").get().exists(), equalTo(true));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("bar").get().exists(), equalTo(false));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("barbaz").get().exists(), equalTo(false));
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("foo").get().getAliases().isEmpty());
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("foobar").get().getAliases().isEmpty());
+        assertTrue(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("bar").get().getAliases().isEmpty());
+        assertTrue(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("barbaz").get().getAliases().isEmpty());
 
         verify(client().admin().indices().prepareAliases().addAlias("*", "foobar_alias"), false);
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("foo").get().exists(), equalTo(true));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("foobar").get().exists(), equalTo(true));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("bar").get().exists(), equalTo(true));
-        assertThat(client().admin().indices().prepareAliasesExist("foobar_alias").setIndices("barbaz").get().exists(), equalTo(true));
-
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("foo").get().getAliases().isEmpty());
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("foobar").get().getAliases().isEmpty());
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("bar").get().getAliases().isEmpty());
+        assertFalse(client().admin().indices().prepareGetAliases("foobar_alias").setIndices("barbaz").get().getAliases().isEmpty());
     }
 
     public void testPutMapping() throws Exception {
@@ -721,14 +687,6 @@ static ValidateQueryRequestBuilder validateQuery(String... indices) {
         return client().admin().indices().prepareValidateQuery(indices);
     }
 
-    private static AliasesExistRequestBuilder aliasExists(String... indices) {
-        return client().admin().indices().prepareAliasesExist("dummy").addIndices(indices);
-    }
-
-    private static TypesExistsRequestBuilder typesExists(String... indices) {
-        return client().admin().indices().prepareTypesExists(indices).setTypes("dummy");
-    }
-
     static GetAliasesRequestBuilder getAliases(String... indices) {
         return client().admin().indices().prepareGetAliases("dummy").addIndices(indices);
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesRequestCacheIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesRequestCacheIT.java
index 12fee85288bc2..98a22717019cf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/IndicesRequestCacheIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/IndicesRequestCacheIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.indices;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeResponse;
 import org.opensearch.action.search.SearchResponse;
@@ -40,13 +42,14 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.cache.request.RequestCacheStats;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
 import java.time.ZoneId;
@@ -54,8 +57,10 @@
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateRange;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
@@ -64,7 +69,23 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 
-public class IndicesRequestCacheIT extends OpenSearchIntegTestCase {
+public class IndicesRequestCacheIT extends ParameterizedOpenSearchIntegTestCase {
+    public IndicesRequestCacheIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     // One of the primary purposes of the query cache is to cache aggs results
     public void testCacheAggs() throws Exception {
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/analysis/PreBuiltAnalyzerIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/analysis/PreBuiltAnalyzerIntegrationIT.java
index a857f6cf6e96c..625f509df16f2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/analysis/PreBuiltAnalyzerIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/analysis/PreBuiltAnalyzerIntegrationIT.java
@@ -36,7 +36,7 @@
 import org.apache.lucene.analysis.TokenStream;
 import org.opensearch.Version;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/analyze/AnalyzeActionIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/analyze/AnalyzeActionIT.java
index 1d25051eefe44..2e6bc7db6cae7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/analyze/AnalyzeActionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/analyze/AnalyzeActionIT.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.admin.indices.analyze.AnalyzeRequestBuilder;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.test.MockKeywordPlugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.MockKeywordPlugin;
 import org.hamcrest.core.IsNull;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/ConcurrentDynamicTemplateIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/ConcurrentDynamicTemplateIT.java
index e731b0074f04d..f732f5c41dec0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/ConcurrentDynamicTemplateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/ConcurrentDynamicTemplateIT.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.indices.mapping;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexResponse;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedClusterManagerGetFieldMappingIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedClusterManagerGetFieldMappingIT.java
new file mode 100644
index 0000000000000..72f7bd44541a6
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedClusterManagerGetFieldMappingIT.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.mapping;
+
+import org.junit.Before;
+
+import static org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import static org.opensearch.test.OpenSearchIntegTestCase.Scope;
+
+@ClusterScope(scope = Scope.TEST, numDataNodes = 0)
+public class DedicatedClusterManagerGetFieldMappingIT extends SimpleGetFieldMappingsIT {
+
+    @Before
+    public void before1() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startNode();
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedMasterGetFieldMappingIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedMasterGetFieldMappingIT.java
deleted file mode 100644
index 98134531d4f31..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/DedicatedMasterGetFieldMappingIT.java
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.mapping;
-
-import org.junit.Before;
-
-import static org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import static org.opensearch.test.OpenSearchIntegTestCase.Scope;
-
-@ClusterScope(scope = Scope.TEST, numDataNodes = 0)
-public class DedicatedMasterGetFieldMappingIT extends SimpleGetFieldMappingsIT {
-
-    @Before
-    public void before1() throws Exception {
-        internalCluster().startMasterOnlyNode();
-        internalCluster().startNode();
-    }
-
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetFieldMappingsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetFieldMappingsIT.java
index 3de2001acd1e7..c6519c1fd851b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetFieldMappingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetFieldMappingsIT.java
@@ -34,14 +34,13 @@
 
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsResponse;
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsResponse.FieldMappingMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -187,22 +186,22 @@ public void testSimpleGetFieldMappingsWithPretty() throws Exception {
             .get();
         XContentBuilder responseBuilder = XContentFactory.jsonBuilder().prettyPrint();
         response.toXContent(responseBuilder, new ToXContent.MapParams(params));
-        String responseStrings = Strings.toString(responseBuilder);
+        String responseStrings = responseBuilder.toString();
 
         XContentBuilder prettyJsonBuilder = XContentFactory.jsonBuilder().prettyPrint();
         prettyJsonBuilder.copyCurrentStructure(createParser(JsonXContent.jsonXContent, responseStrings));
-        assertThat(responseStrings, equalTo(Strings.toString(prettyJsonBuilder)));
+        assertThat(responseStrings, equalTo(prettyJsonBuilder.toString()));
 
         params.put("pretty", "false");
 
         response = client().admin().indices().prepareGetFieldMappings("index").setFields("field1", "obj.subfield").get();
         responseBuilder = XContentFactory.jsonBuilder().prettyPrint().lfAtEnd();
         response.toXContent(responseBuilder, new ToXContent.MapParams(params));
-        responseStrings = Strings.toString(responseBuilder);
+        responseStrings = responseBuilder.toString();
 
         prettyJsonBuilder = XContentFactory.jsonBuilder().prettyPrint();
         prettyJsonBuilder.copyCurrentStructure(createParser(JsonXContent.jsonXContent, responseStrings));
-        assertThat(responseStrings, not(equalTo(Strings.toString(prettyJsonBuilder))));
+        assertThat(responseStrings, not(equalTo(prettyJsonBuilder).toString()));
 
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetMappingsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetMappingsIT.java
index f54e60a8baa88..4ca808a1e66e6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetMappingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/SimpleGetMappingsIT.java
@@ -36,10 +36,10 @@
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.common.Priority;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/UpdateMappingIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/UpdateMappingIntegrationIT.java
index 0a29794add5a8..575c1956d0fda 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/mapping/UpdateMappingIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/mapping/UpdateMappingIntegrationIT.java
@@ -43,17 +43,16 @@
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
@@ -153,7 +152,7 @@ public void testUpdateMappingWithoutType() {
         AcknowledgedResponse putMappingResponse = client().admin()
             .indices()
             .preparePutMapping("test")
-            .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", XContentType.JSON)
+            .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", MediaTypeRegistry.JSON)
             .execute()
             .actionGet();
 
@@ -178,7 +177,7 @@ public void testUpdateMappingWithoutTypeMultiObjects() {
         AcknowledgedResponse putMappingResponse = client().admin()
             .indices()
             .preparePutMapping("test")
-            .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", XContentType.JSON)
+            .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", MediaTypeRegistry.JSON)
             .execute()
             .actionGet();
 
@@ -207,7 +206,7 @@ public void testUpdateMappingWithConflicts() {
                 .preparePutMapping("test")
                 .setSource(
                     "{\"" + MapperService.SINGLE_MAPPING_NAME + "\":{\"properties\":{\"body\":{\"type\":\"integer\"}}}}",
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
                 .execute()
                 .actionGet();
@@ -230,7 +229,7 @@ public void testUpdateMappingWithNormsConflicts() {
                 .preparePutMapping("test")
                 .setSource(
                     "{\"" + MapperService.SINGLE_MAPPING_NAME + "\":{\"properties\":{\"body\":{\"type\":\"text\", \"norms\": true }}}}",
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
                 .execute()
                 .actionGet();
@@ -256,7 +255,7 @@ public void testUpdateMappingNoChanges() {
         AcknowledgedResponse putMappingResponse = client().admin()
             .indices()
             .preparePutMapping("test")
-            .setSource("{\"properties\":{\"body\":{\"type\":\"text\"}}}", XContentType.JSON)
+            .setSource("{\"properties\":{\"body\":{\"type\":\"text\"}}}", MediaTypeRegistry.JSON)
             .execute()
             .actionGet();
 
@@ -306,7 +305,7 @@ public void testUpdateMappingConcurrently() throws Throwable {
                                     .endObject()
                                     .endObject()
                             )
-                            .setMasterNodeTimeout(TimeValue.timeValueMinutes(5))
+                            .setClusterManagerNodeTimeout(TimeValue.timeValueMinutes(5))
                             .get();
 
                         assertThat(response.isAcknowledged(), equalTo(true));
@@ -347,7 +346,7 @@ public void testPutMappingsWithBlocks() {
                     client().admin()
                         .indices()
                         .preparePutMapping("test")
-                        .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", XContentType.JSON)
+                        .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", MediaTypeRegistry.JSON)
                 );
             } finally {
                 disableIndexBlock("test", block);
@@ -361,7 +360,7 @@ public void testPutMappingsWithBlocks() {
                     client().admin()
                         .indices()
                         .preparePutMapping("test")
-                        .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", XContentType.JSON)
+                        .setSource("{\"properties\":{\"date\":{\"type\":\"integer\"}}}", MediaTypeRegistry.JSON)
                 );
             } finally {
                 disableIndexBlock("test", block);
@@ -386,13 +385,13 @@ private void assertConcreteMappingsOnAll(final String index, final String... fie
                 assertNotNull("field " + fieldName + " doesn't exists on " + node, fieldType);
             }
         }
-        assertMappingOnMaster(index, fieldNames);
+        assertMappingOnClusterManager(index, fieldNames);
     }
 
     /**
-     * Waits for the given mapping type to exists on the master node.
+     * Waits for the given mapping type to exists on the cluster-manager node.
      */
-    private void assertMappingOnMaster(final String index, final String... fieldNames) {
+    private void assertMappingOnClusterManager(final String index, final String... fieldNames) {
         GetMappingsResponse response = client().admin().indices().prepareGetMappings(index).get();
         MappingMetadata mappings = response.getMappings().get(index);
         assertThat(mappings, notNullValue());
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/CircuitBreakerServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/CircuitBreakerServiceIT.java
index 2dc6b2085b866..dfe6889df2319 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/CircuitBreakerServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/CircuitBreakerServiceIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.indices.memory.breaker;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -46,25 +48,27 @@
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.indices.breaker.CircuitBreakerStats;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerStats;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.After;
 import org.junit.Before;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -73,12 +77,13 @@
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.BREAKER;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.cardinality;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.OpenSearchIntegTestCase.Scope.TEST;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
-
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.Matchers.equalTo;
@@ -89,7 +94,32 @@
  * Integration tests for InternalCircuitBreakerService
  */
 @ClusterScope(scope = TEST, numClientNodes = 0, maxNumDataNodes = 1)
-public class CircuitBreakerServiceIT extends OpenSearchIntegTestCase {
+public class CircuitBreakerServiceIT extends ParameterizedOpenSearchIntegTestCase {
+    public CircuitBreakerServiceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY, randomIntBetween(1, 2))
+            .build();
+    }
+
     /** Reset all breaker settings back to their defaults */
     private void reset() {
         logger.info("--> resetting breaker settings");
@@ -197,7 +227,7 @@ public void testRamAccountingTermsEnum() throws Exception {
             prepareCreate("ramtest").setSource(
                 "{\"mappings\": {\"type\": {\"properties\": {\"test\": "
                     + "{\"type\": \"text\",\"fielddata\": true,\"fielddata_frequency_filter\": {\"max\": 10000}}}}}}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/RandomExceptionCircuitBreakerIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/RandomExceptionCircuitBreakerIT.java
index 341c0a965f94e..6d87cafdd4216 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/RandomExceptionCircuitBreakerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/memory/breaker/RandomExceptionCircuitBreakerIT.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.LeafReader;
-
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -43,13 +42,12 @@
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.breaker.CircuitBreaker;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.indices.IndicesService;
@@ -70,7 +68,6 @@
 
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.BREAKER;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
-
 import static org.hamcrest.Matchers.equalTo;
 
 /**
@@ -99,22 +96,20 @@ public void testBreakerWithRandomExceptions() throws IOException, InterruptedExc
             assertThat("Breaker is not set to 0", node.getBreaker().getStats(CircuitBreaker.FIELDDATA).getEstimated(), equalTo(0L));
         }
 
-        String mapping = Strings // {}
-            .toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("test-str")
-                    .field("type", "keyword")
-                    .field("doc_values", randomBoolean())
-                    .endObject() // test-str
-                    .startObject("test-num")
-                    // I don't use randomNumericType() here because I don't want "byte", and I want "float" and "double"
-                    .field("type", randomFrom(Arrays.asList("float", "long", "double", "short", "integer")))
-                    .endObject() // test-num
-                    .endObject() // properties
-                    .endObject()
-            );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("test-str")
+            .field("type", "keyword")
+            .field("doc_values", randomBoolean())
+            .endObject() // test-str
+            .startObject("test-num")
+            // I don't use randomNumericType() here because I don't want "byte", and I want "float" and "double"
+            .field("type", randomFrom(Arrays.asList("float", "long", "double", "short", "integer")))
+            .endObject() // test-num
+            .endObject() // properties
+            .endObject()
+            .toString();
         final double topLevelRate;
         final double lowLevelRate;
         if (frequently()) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/DanglingIndicesIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/DanglingIndicesIT.java
index ede18af80f6ca..8fd7961cab3a7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/DanglingIndicesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/DanglingIndicesIT.java
@@ -40,11 +40,11 @@
 import org.opensearch.action.admin.indices.dangling.list.NodeListDanglingIndicesResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.InternalTestCluster;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexPrimaryRelocationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexPrimaryRelocationIT.java
index 08cf33a342c65..c049c8ed2d4a6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexPrimaryRelocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexPrimaryRelocationIT.java
@@ -56,14 +56,13 @@ public class IndexPrimaryRelocationIT extends OpenSearchIntegTestCase {
 
     private static final int RELOCATION_COUNT = 15;
 
+    public Settings indexSettings() {
+        return Settings.builder().put("index.number_of_shards", 1).put("index.number_of_replicas", 0).build();
+    }
+
     public void testPrimaryRelocationWhileIndexing() throws Exception {
         internalCluster().ensureAtLeastNumDataNodes(randomIntBetween(2, 3));
-        client().admin()
-            .indices()
-            .prepareCreate("test")
-            .setSettings(Settings.builder().put("index.number_of_shards", 1).put("index.number_of_replicas", 0))
-            .setMapping("field", "type=text")
-            .get();
+        client().admin().indices().prepareCreate("test").setSettings(indexSettings()).setMapping("field", "type=text").get();
         ensureGreen("test");
         AtomicInteger numAutoGenDocs = new AtomicInteger();
         final AtomicBoolean finished = new AtomicBoolean(false);
@@ -83,7 +82,7 @@ public void run() {
         indexingThread.start();
 
         ClusterState initialState = client().admin().cluster().prepareState().get().getState();
-        DiscoveryNode[] dataNodes = initialState.getNodes().getDataNodes().values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] dataNodes = initialState.getNodes().getDataNodes().values().toArray(new DiscoveryNode[0]);
         DiscoveryNode relocationSource = initialState.getNodes()
             .getDataNodes()
             .get(initialState.getRoutingTable().shardRoutingTable("test", 0).primaryShard().currentNodeId());
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
index a7dc77e024d5c..e4f1f8717f899 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.index.IndexCommit;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -72,18 +71,20 @@
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.gateway.ReplicaShardAllocatorIT;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MockEngineFactoryPlugin;
@@ -95,13 +96,13 @@
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreStats;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.NodeIndicesStats;
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.indices.recovery.RecoveryState.Stage;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.node.RecoverySettingsChunkSizePlugin;
 import org.opensearch.plugins.AnalysisPlugin;
@@ -130,6 +131,7 @@
 import org.opensearch.transport.TransportRequestHandler;
 import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportService;
+import org.hamcrest.Matcher;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -138,6 +140,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Spliterators;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Semaphore;
@@ -151,6 +154,11 @@
 
 import static java.util.Collections.singletonMap;
 import static java.util.stream.Collectors.toList;
+import static org.opensearch.action.DocWriteResponse.Result.CREATED;
+import static org.opensearch.action.DocWriteResponse.Result.UPDATED;
+import static org.opensearch.node.RecoverySettingsChunkSizePlugin.CHUNK_SIZE_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.everyItem;
@@ -161,11 +169,6 @@
 import static org.hamcrest.Matchers.isOneOf;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.not;
-import static org.opensearch.action.DocWriteResponse.Result.CREATED;
-import static org.opensearch.action.DocWriteResponse.Result.UPDATED;
-import static org.opensearch.node.RecoverySettingsChunkSizePlugin.CHUNK_SIZE_SETTING;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 
 @ClusterScope(scope = Scope.TEST, numDataNodes = 0)
 public class IndexRecoveryIT extends OpenSearchIntegTestCase {
@@ -575,21 +578,25 @@ public void testRerouteRecovery() throws Exception {
                 .clear()
                 .setIndices(new CommonStatsFlags(CommonStatsFlags.Flag.Recovery))
                 .get();
-            assertThat(statsResponse1.getNodes(), hasSize(2));
-            for (NodeStats nodeStats : statsResponse1.getNodes()) {
+            List<NodeStats> dataNodeStats = statsResponse1.getNodes()
+                .stream()
+                .filter(nodeStats -> nodeStats.getNode().isDataNode())
+                .collect(Collectors.toList());
+            assertThat(dataNodeStats, hasSize(2));
+            for (NodeStats nodeStats : dataNodeStats) {
                 final RecoveryStats recoveryStats = nodeStats.getIndices().getRecoveryStats();
                 if (nodeStats.getNode().getName().equals(nodeA)) {
                     assertThat(
                         "node A throttling should increase",
                         recoveryStats.throttleTime().millis(),
-                        greaterThan(finalNodeAThrottling)
+                        getMatcherForThrottling(finalNodeAThrottling)
                     );
                 }
                 if (nodeStats.getNode().getName().equals(nodeB)) {
                     assertThat(
                         "node B throttling should increase",
                         recoveryStats.throttleTime().millis(),
-                        greaterThan(finalNodeBThrottling)
+                        getMatcherForThrottling(finalNodeBThrottling)
                     );
                 }
             }
@@ -621,7 +628,7 @@ public void testRerouteRecovery() throws Exception {
             final RecoveryStats recoveryStats = nodeStats.getIndices().getRecoveryStats();
             assertThat(recoveryStats.currentAsSource(), equalTo(0));
             assertThat(recoveryStats.currentAsTarget(), equalTo(0));
-            assertThat(nodeName + " throttling should be >0", recoveryStats.throttleTime().millis(), greaterThan(0L));
+            assertThat(nodeName + " throttling should be >0", recoveryStats.throttleTime().millis(), getMatcherForThrottling(0));
         };
         // we have to use assertBusy as recovery counters are decremented only when the last reference to the RecoveryTarget
         // is decremented, which may happen after the recovery was done.
@@ -642,7 +649,8 @@ public void testRerouteRecovery() throws Exception {
 
         logger.info("--> start node C");
         String nodeC = internalCluster().startNode();
-        assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("3").get().isTimedOut());
+        int nodeCount = internalCluster().getNodeNames().length;
+        assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes(String.valueOf(nodeCount)).get().isTimedOut());
 
         logger.info("--> slowing down recoveries");
         slowDownRecovery(shardSize);
@@ -676,7 +684,7 @@ public void testRerouteRecovery() throws Exception {
         assertOnGoingRecoveryState(nodeCRecoveryStates.get(0), 0, PeerRecoverySource.INSTANCE, false, nodeB, nodeC);
         validateIndexRecoveryState(nodeCRecoveryStates.get(0).getIndex());
 
-        if (randomBoolean()) {
+        if (randomBoolean() && shouldAssertOngoingRecoveryInRerouteRecovery()) {
             // shutdown node with relocation source of replica shard and check if recovery continues
             internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeA));
             ensureStableCluster(2);
@@ -720,6 +728,14 @@ public void testRerouteRecovery() throws Exception {
         validateIndexRecoveryState(nodeCRecoveryStates.get(0).getIndex());
     }
 
+    protected boolean shouldAssertOngoingRecoveryInRerouteRecovery() {
+        return false;
+    }
+
+    protected Matcher<Long> getMatcherForThrottling(long value) {
+        return greaterThan(value);
+    }
+
     public void testSnapshotRecovery() throws Exception {
         logger.info("--> start node A");
         String nodeA = internalCluster().startNode();
@@ -774,7 +790,7 @@ public void testSnapshotRecovery() throws Exception {
         logger.info("--> request recoveries");
         RecoveryResponse response = client().admin().indices().prepareRecoveries(INDEX_NAME).execute().actionGet();
 
-        Repository repository = internalCluster().getMasterNodeInstance(RepositoriesService.class).repository(REPO_NAME);
+        Repository repository = internalCluster().getClusterManagerNodeInstance(RepositoriesService.class).repository(REPO_NAME);
         final RepositoryData repositoryData = PlainActionFuture.get(repository::getRepositoryData);
         for (Map.Entry<String, List<RecoveryState>> indexRecoveryStates : response.shardRecoveryStates().entrySet()) {
 
@@ -822,7 +838,7 @@ private IndicesStatsResponse createAndPopulateIndex(String name, int nodeCount,
         ensureGreen();
 
         logger.info("--> indexing sample data");
-        final int numDocs = between(MIN_DOC_COUNT, MAX_DOC_COUNT);
+        final int numDocs = numDocs();
         final IndexRequestBuilder[] docs = new IndexRequestBuilder[numDocs];
 
         for (int i = 0; i < numDocs; i++) {
@@ -836,7 +852,7 @@ private IndicesStatsResponse createAndPopulateIndex(String name, int nodeCount,
         return client().admin().indices().prepareStats(name).execute().actionGet();
     }
 
-    private void validateIndexRecoveryState(RecoveryState.Index indexState) {
+    private void validateIndexRecoveryState(ReplicationLuceneIndex indexState) {
         assertThat(indexState.time(), greaterThanOrEqualTo(0L));
         assertThat(indexState.recoveredFilesPercent(), greaterThanOrEqualTo(0.0f));
         assertThat(indexState.recoveredFilesPercent(), lessThanOrEqualTo(100.0f));
@@ -844,6 +860,10 @@ private void validateIndexRecoveryState(RecoveryState.Index indexState) {
         assertThat(indexState.recoveredBytesPercent(), lessThanOrEqualTo(100.0f));
     }
 
+    protected int numDocs() {
+        return between(MIN_DOC_COUNT, MAX_DOC_COUNT);
+    }
+
     public void testTransientErrorsDuringRecoveryAreRetried() throws Exception {
         final String indexName = "test";
         final Settings nodeSettings = Settings.builder()
@@ -851,7 +871,7 @@ public void testTransientErrorsDuringRecoveryAreRetried() throws Exception {
             .put(NodeConnectionsService.CLUSTER_NODE_RECONNECT_INTERVAL_SETTING.getKey(), "500ms")
             .put(RecoverySettings.INDICES_RECOVERY_INTERNAL_ACTION_TIMEOUT_SETTING.getKey(), "10s")
             .build();
-        // start a master node
+        // start a cluster-manager node
         internalCluster().startNode(nodeSettings);
 
         final String blueNodeName = internalCluster().startNode(
@@ -879,14 +899,14 @@ public void testTransientErrorsDuringRecoveryAreRetried() throws Exception {
         // is a mix of file chunks and translog ops
         int threeFourths = (int) (numDocs * 0.75);
         for (int i = 0; i < threeFourths; i++) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         flush(indexName);
         requests.clear();
 
         for (int i = threeFourths; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         ensureSearchable(indexName);
@@ -1053,7 +1073,7 @@ public void testDisconnectsWhileRecovering() throws Exception {
             .put(RecoverySettings.INDICES_RECOVERY_INTERNAL_ACTION_TIMEOUT_SETTING.getKey(), "1s")
             .put(NodeConnectionsService.CLUSTER_NODE_RECONNECT_INTERVAL_SETTING.getKey(), "1s")
             .build();
-        // start a master node
+        // start a cluster-manager node
         internalCluster().startNode(nodeSettings);
 
         final String blueNodeName = internalCluster().startNode(
@@ -1078,7 +1098,7 @@ public void testDisconnectsWhileRecovering() throws Exception {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         ensureSearchable(indexName);
@@ -1210,8 +1230,8 @@ public void testDisconnectsDuringRecovery() throws Exception {
             )
             .build();
         TimeValue disconnectAfterDelay = TimeValue.timeValueMillis(randomIntBetween(0, 100));
-        // start a master node
-        String masterNodeName = internalCluster().startMasterOnlyNode(nodeSettings);
+        // start a cluster-manager node
+        String clusterManagerNodeName = internalCluster().startClusterManagerOnlyNode(nodeSettings);
 
         final String blueNodeName = internalCluster().startNode(
             Settings.builder().put("node.attr.color", "blue").put(nodeSettings).build()
@@ -1232,15 +1252,15 @@ public void testDisconnectsDuringRecovery() throws Exception {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         ensureSearchable(indexName);
         assertHitCount(client().prepareSearch(indexName).get(), numDocs);
 
-        MockTransportService masterTransportService = (MockTransportService) internalCluster().getInstance(
+        MockTransportService clusterManagerTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            masterNodeName
+            clusterManagerNodeName
         );
         MockTransportService blueMockTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
@@ -1311,7 +1331,7 @@ public void sendRequest(
         });
 
         for (MockTransportService mockTransportService : Arrays.asList(redMockTransportService, blueMockTransportService)) {
-            mockTransportService.addSendBehavior(masterTransportService, (connection, requestId, action, request, options) -> {
+            mockTransportService.addSendBehavior(clusterManagerTransportService, (connection, requestId, action, request, options) -> {
                 logger.info("--> sending request {} on {}", action, connection.getNode());
                 if ((primaryRelocation && finalized.get()) == false) {
                     assertNotEquals(action, ShardStateAction.SHARD_FAILED_ACTION_NAME);
@@ -1375,17 +1395,17 @@ public void testHistoryRetention() throws Exception {
         final List<IndexRequestBuilder> requests = new ArrayList<>();
         final int replicatedDocCount = scaledRandomIntBetween(25, 250);
         while (requests.size() < replicatedDocCount) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         if (randomBoolean()) {
             flush(indexName);
         }
 
-        String firstNodeToStop = randomFrom(internalCluster().getNodeNames());
+        String firstNodeToStop = randomFrom(internalCluster().getDataNodeNames());
         Settings firstNodeToStopDataPathSettings = internalCluster().dataPathSettings(firstNodeToStop);
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(firstNodeToStop));
-        String secondNodeToStop = randomFrom(internalCluster().getNodeNames());
+        String secondNodeToStop = randomFrom(internalCluster().getDataNodeNames());
         Settings secondNodeToStopDataPathSettings = internalCluster().dataPathSettings(secondNodeToStop);
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(secondNodeToStop));
 
@@ -1397,7 +1417,7 @@ public void testHistoryRetention() throws Exception {
 
         final int numNewDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numNewDocs; i++) {
-            client().prepareIndex(indexName).setSource("{}", XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE).get();
+            client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE).get();
         }
         // Flush twice to update the safe commit's local checkpoint
         assertThat(client().admin().indices().prepareFlush(indexName).setForce(true).execute().get().getFailedShards(), equalTo(0));
@@ -1438,7 +1458,7 @@ public void testDoNotInfinitelyWaitForMapping() {
         for (int i = 0; i < numDocs; i++) {
             client().prepareIndex("test")
                 .setId("u" + i)
-                .setSource(singletonMap("test_field", Integer.toString(i)), XContentType.JSON)
+                .setSource(singletonMap("test_field", Integer.toString(i)), MediaTypeRegistry.JSON)
                 .get();
         }
         Semaphore recoveryBlocked = new Semaphore(1);
@@ -1465,8 +1485,8 @@ public void testDoNotInfinitelyWaitForMapping() {
         assertHitCount(client().prepareSearch().get(), numDocs);
     }
 
-    /** Makes sure the new master does not repeatedly fetch index metadata from recovering replicas */
-    public void testOngoingRecoveryAndMasterFailOver() throws Exception {
+    /** Makes sure the new cluster-manager does not repeatedly fetch index metadata from recovering replicas */
+    public void testOngoingRecoveryAndClusterManagerFailOver() throws Exception {
         String indexName = "test";
         internalCluster().startNodes(2);
         String nodeWithPrimary = internalCluster().startDataOnlyNode();
@@ -1510,7 +1530,7 @@ public void testOngoingRecoveryAndMasterFailOver() throws Exception {
             );
             phase1ReadyBlocked.await();
             internalCluster().restartNode(
-                clusterService().state().nodes().getMasterNode().getName(),
+                clusterService().state().nodes().getClusterManagerNode().getName(),
                 new InternalTestCluster.RestartCallback()
             );
             internalCluster().ensureAtLeastNumDataNodes(3);
@@ -1535,8 +1555,8 @@ public void testRecoverLocallyUpToGlobalCheckpoint() throws Exception {
         internalCluster().ensureAtLeastNumDataNodes(2);
         List<String> nodes = randomSubsetOf(
             2,
-            StreamSupport.stream(clusterService().state().nodes().getDataNodes().spliterator(), false)
-                .map(node -> node.value.getName())
+            StreamSupport.stream(Spliterators.spliterator(clusterService().state().nodes().getDataNodes().values(), 0), false)
+                .map(node -> node.getName())
                 .collect(Collectors.toSet())
         );
         String indexName = "test-index";
@@ -1588,7 +1608,10 @@ public void testRecoverLocallyUpToGlobalCheckpoint() throws Exception {
                         .getShard(0)
                         .getRetentionLeases();
                     throw new AssertionError(
-                        "expect an operation-based recovery:" + "retention leases" + Strings.toString(retentionLeases) + "]"
+                        "expect an operation-based recovery:"
+                            + "retention leases"
+                            + Strings.toString(MediaTypeRegistry.JSON, retentionLeases)
+                            + "]"
                     );
                 }
                 connection.sendRequest(requestId, action, request, options);
@@ -2084,7 +2107,7 @@ public void testRepeatedRecovery() throws Exception {
     }
 
     public void testAllocateEmptyPrimaryResetsGlobalCheckpoint() throws Exception {
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         final List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
         final Settings randomNodeDataPathSettings = internalCluster().dataPathSettings(randomFrom(dataNodes));
         final String indexName = "test";
@@ -2164,7 +2187,10 @@ public void testPeerRecoveryTrimsLocalTranslog() throws Exception {
                 while (stopped.get() == false) {
                     try {
                         IndexResponse response = client().prepareIndex(indexName)
-                            .setSource(Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()), XContentType.JSON)
+                            .setSource(
+                                Collections.singletonMap("f" + randomIntBetween(1, 10), randomNonNegativeLong()),
+                                MediaTypeRegistry.JSON
+                            )
                             .get();
                         assertThat(response.getResult(), isOneOf(CREATED, UPDATED));
                     } catch (IllegalStateException | OpenSearchException ignored) {}
@@ -2184,7 +2210,7 @@ public void testPeerRecoveryTrimsLocalTranslog() throws Exception {
     }
 
     public void testCancelRecoveryWithAutoExpandReplicas() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         assertAcked(
             client().admin()
                 .indices()
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/ReplicaToPrimaryPromotionIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/ReplicaToPrimaryPromotionIT.java
index b74dc2f4236a0..3df4ecff5250c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/ReplicaToPrimaryPromotionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/ReplicaToPrimaryPromotionIT.java
@@ -38,8 +38,8 @@
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.test.BackgroundIndexer;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Locale;
 
@@ -80,7 +80,7 @@ public void testPromoteReplicaToPrimary() throws Exception {
         }
 
         // pick up a data node that contains a random primary shard
-        ClusterState state = client(internalCluster().getMasterName()).admin().cluster().prepareState().get().getState();
+        ClusterState state = client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
         final int numShards = state.metadata().index(indexName).getNumberOfShards();
         final ShardRouting primaryShard = state.routingTable().index(indexName).shard(randomIntBetween(0, numShards - 1)).primaryShard();
         final DiscoveryNode randomNode = state.nodes().resolveNode(primaryShard.currentNodeId());
@@ -89,7 +89,7 @@ public void testPromoteReplicaToPrimary() throws Exception {
         internalCluster().stopRandomNode(InternalTestCluster.nameFilter(randomNode.getName()));
         ensureYellowAndNoInitializingShards(indexName);
 
-        state = client(internalCluster().getMasterName()).admin().cluster().prepareState().get().getState();
+        state = client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
         for (IndexShardRoutingTable shardRoutingTable : state.routingTable().index(indexName)) {
             for (ShardRouting shardRouting : shardRoutingTable.activeShards()) {
                 assertThat(shardRouting + " should be promoted as a primary", shardRouting.primary(), is(true));
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationAllocationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationAllocationIT.java
new file mode 100644
index 0000000000000..bdefd7a5e199a
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationAllocationIT.java
@@ -0,0 +1,283 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.OpenSearchAllocationTestCase.ShardAllocations;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.index.IndexModule;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationAllocationIT extends SegmentReplicationBaseIT {
+
+    private void createIndex(String idxName, int shardCount, int replicaCount, boolean isSegRep) {
+        Settings.Builder builder = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, shardCount)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, replicaCount);
+        if (isSegRep) {
+            builder = builder.put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+        } else {
+            builder = builder.put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT);
+        }
+        prepareCreate(idxName, builder).get();
+    }
+
+    public void enablePreferPrimaryBalance() {
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put(BalancedShardsAllocator.PREFER_PRIMARY_SHARD_BALANCE.getKey(), "true"))
+        );
+    }
+
+    /**
+     * This test verifies that the overall primary balance is attained during allocation. This test verifies primary
+     * balance per index and across all indices is maintained.
+     */
+    public void testGlobalPrimaryAllocation() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final int maxReplicaCount = 1;
+        final int maxShardCount = 1;
+        final int nodeCount = randomIntBetween(maxReplicaCount + 1, 10);
+        final int numberOfIndices = randomIntBetween(5, 10);
+
+        final List<String> nodeNames = new ArrayList<>();
+        logger.info("--> Creating {} nodes", nodeCount);
+        for (int i = 0; i < nodeCount; i++) {
+            nodeNames.add(internalCluster().startNode());
+        }
+        enablePreferPrimaryBalance();
+        int shardCount, replicaCount;
+        ClusterState state;
+        for (int i = 0; i < numberOfIndices; i++) {
+            shardCount = randomIntBetween(1, maxShardCount);
+            replicaCount = randomIntBetween(0, maxReplicaCount);
+            createIndex("test" + i, shardCount, replicaCount, i % 2 == 0);
+            logger.info("--> Creating index {} with shard count {} and replica count {}", "test" + i, shardCount, replicaCount);
+            ensureGreen(TimeValue.timeValueSeconds(60));
+        }
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+        verifyPrimaryBalance();
+    }
+
+    /**
+     * This test verifies the happy path where primary shard allocation is balanced when multiple indices are created.
+     *
+     * This test in general passes without primary shard balance as well due to nature of allocation algorithm which
+     * assigns all primary shards first followed by replica copies.
+     */
+    public void testPerIndexPrimaryAllocation() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final int maxReplicaCount = 2;
+        final int maxShardCount = 5;
+        final int nodeCount = randomIntBetween(maxReplicaCount + 1, 10);
+        final int numberOfIndices = randomIntBetween(5, 10);
+
+        final List<String> nodeNames = new ArrayList<>();
+        logger.info("--> Creating {} nodes", nodeCount);
+        for (int i = 0; i < nodeCount; i++) {
+            nodeNames.add(internalCluster().startNode());
+        }
+        enablePreferPrimaryBalance();
+        int shardCount, replicaCount;
+        ClusterState state;
+        for (int i = 0; i < numberOfIndices; i++) {
+            shardCount = randomIntBetween(1, maxShardCount);
+            replicaCount = randomIntBetween(0, maxReplicaCount);
+            createIndex("test" + i, shardCount, replicaCount, i % 2 == 0);
+            logger.info("--> Creating index {} with shard count {} and replica count {}", "test" + i, shardCount, replicaCount);
+            ensureGreen(TimeValue.timeValueSeconds(60));
+            state = client().admin().cluster().prepareState().execute().actionGet().getState();
+            logger.info(ShardAllocations.printShardDistribution(state));
+        }
+        verifyPerIndexPrimaryBalance();
+    }
+
+    /**
+     * This test verifies balanced primary shard allocation for a single index with large shard count in event of node
+     * going down and a new node joining the cluster. The results in shard distribution skewness and re-balancing logic
+     * ensures the primary shard distribution is balanced.
+     *
+     */
+    public void testSingleIndexShardAllocation() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final int maxReplicaCount = 1;
+        final int maxShardCount = 50;
+        final int nodeCount = 5;
+
+        final List<String> nodeNames = new ArrayList<>();
+        logger.info("--> Creating {} nodes", nodeCount);
+        for (int i = 0; i < nodeCount; i++) {
+            nodeNames.add(internalCluster().startNode());
+        }
+        enablePreferPrimaryBalance();
+
+        ClusterState state;
+        createIndex("test", maxShardCount, maxReplicaCount, true);
+        ensureGreen(TimeValue.timeValueSeconds(60));
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+
+        // Remove a node
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeNames.get(0)));
+        ensureGreen(TimeValue.timeValueSeconds(60));
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+
+        // Add a new node
+        internalCluster().startDataOnlyNode();
+        ensureGreen(TimeValue.timeValueSeconds(60));
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+    }
+
+    /**
+     * Similar to testSingleIndexShardAllocation test but creates multiple indices, multiple nodes adding in and getting
+     * removed. The test asserts post each such event that primary shard distribution is balanced for each index.
+     */
+    public void testAllocationWithDisruption() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final int maxReplicaCount = 2;
+        final int maxShardCount = 2;
+        // Create higher number of nodes than number of shards to reduce chances of SameShardAllocationDecider kicking-in
+        // and preventing primary relocations
+        final int nodeCount = randomIntBetween(5, 10);
+        final int numberOfIndices = randomIntBetween(1, 10);
+
+        logger.info("--> Creating {} nodes", nodeCount);
+        final List<String> nodeNames = new ArrayList<>();
+        for (int i = 0; i < nodeCount; i++) {
+            nodeNames.add(internalCluster().startNode());
+        }
+        enablePreferPrimaryBalance();
+
+        int shardCount, replicaCount;
+        ClusterState state;
+        for (int i = 0; i < numberOfIndices; i++) {
+            shardCount = randomIntBetween(1, maxShardCount);
+            replicaCount = randomIntBetween(1, maxReplicaCount);
+            logger.info("--> Creating index test{} with primary {} and replica {}", i, shardCount, replicaCount);
+            createIndex("test" + i, shardCount, replicaCount, i % 2 == 0);
+            ensureGreen(TimeValue.timeValueSeconds(60));
+            if (logger.isTraceEnabled()) {
+                state = client().admin().cluster().prepareState().execute().actionGet().getState();
+                logger.info(ShardAllocations.printShardDistribution(state));
+            }
+        }
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+
+        final int additionalNodeCount = randomIntBetween(1, 5);
+        logger.info("--> Adding {} nodes", additionalNodeCount);
+
+        internalCluster().startNodes(additionalNodeCount);
+        ensureGreen(TimeValue.timeValueSeconds(60));
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+
+        int nodeCountToStop = additionalNodeCount;
+        while (nodeCountToStop > 0) {
+            internalCluster().stopRandomDataNode();
+            // give replica a chance to promote as primary before terminating node containing the replica
+            ensureGreen(TimeValue.timeValueSeconds(60));
+            nodeCountToStop--;
+        }
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        logger.info("--> Cluster state post nodes stop {}", state);
+        logger.info(ShardAllocations.printShardDistribution(state));
+        verifyPerIndexPrimaryBalance();
+    }
+
+    /**
+     * Utility method which ensures cluster has balanced primary shard distribution across a single index.
+     * @throws Exception exception
+     */
+    private void verifyPerIndexPrimaryBalance() throws Exception {
+        assertBusy(() -> {
+            final ClusterState currentState = client().admin().cluster().prepareState().execute().actionGet().getState();
+            RoutingNodes nodes = currentState.getRoutingNodes();
+            for (final Map.Entry<String, IndexRoutingTable> index : currentState.getRoutingTable().indicesRouting().entrySet()) {
+                final int totalPrimaryShards = index.getValue().primaryShardsActive();
+                final int lowerBoundPrimaryShardsPerNode = (int) Math.floor(totalPrimaryShards * 1f / currentState.getRoutingNodes().size())
+                    - 1;
+                final int upperBoundPrimaryShardsPerNode = (int) Math.ceil(totalPrimaryShards * 1f / currentState.getRoutingNodes().size())
+                    + 1;
+                for (RoutingNode node : nodes) {
+                    final int primaryCount = node.shardsWithState(index.getKey(), STARTED)
+                        .stream()
+                        .filter(ShardRouting::primary)
+                        .collect(Collectors.toList())
+                        .size();
+                    // Asserts value is within the variance threshold (-1/+1 of the average value).
+                    assertTrue(
+                        "--> Primary balance assertion failure for index "
+                            + index
+                            + "on node "
+                            + node.node().getName()
+                            + " "
+                            + lowerBoundPrimaryShardsPerNode
+                            + " <= "
+                            + primaryCount
+                            + " (assigned) <= "
+                            + upperBoundPrimaryShardsPerNode,
+                        lowerBoundPrimaryShardsPerNode <= primaryCount && primaryCount <= upperBoundPrimaryShardsPerNode
+                    );
+                }
+            }
+        }, 60, TimeUnit.SECONDS);
+    }
+
+    private void verifyPrimaryBalance() throws Exception {
+        assertBusy(() -> {
+            final ClusterState currentState = client().admin().cluster().prepareState().execute().actionGet().getState();
+            RoutingNodes nodes = currentState.getRoutingNodes();
+            int totalPrimaryShards = 0;
+            for (final IndexRoutingTable index : currentState.getRoutingTable().indicesRouting().values()) {
+                totalPrimaryShards += index.primaryShardsActive();
+            }
+            final int avgPrimaryShardsPerNode = (int) Math.ceil(totalPrimaryShards * 1f / currentState.getRoutingNodes().size());
+            for (RoutingNode node : nodes) {
+                final int primaryCount = node.shardsWithState(STARTED)
+                    .stream()
+                    .filter(ShardRouting::primary)
+                    .collect(Collectors.toList())
+                    .size();
+                assertTrue(primaryCount <= avgPrimaryShardsPerNode);
+            }
+        }, 60, TimeUnit.SECONDS);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationBaseIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationBaseIT.java
new file mode 100644
index 0000000000000..8e68a8bde39d5
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationBaseIT.java
@@ -0,0 +1,249 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.test.OpenSearchIntegTestCase.client;
+import static org.opensearch.test.OpenSearchTestCase.assertBusy;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+public class SegmentReplicationBaseIT extends OpenSearchIntegTestCase {
+
+    protected static final String INDEX_NAME = "test-idx-1";
+    protected static final int SHARD_COUNT = 1;
+    protected static final int REPLICA_COUNT = 1;
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return asList(MockTransportService.TestPlugin.class);
+    }
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, SHARD_COUNT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    @Nullable
+    protected ShardRouting getShardRoutingForNodeName(String nodeName) {
+        final ClusterState state = getClusterState();
+        for (IndexShardRoutingTable shardRoutingTable : state.routingTable().index(INDEX_NAME)) {
+            for (ShardRouting shardRouting : shardRoutingTable.activeShards()) {
+                final String nodeId = shardRouting.currentNodeId();
+                final DiscoveryNode discoveryNode = state.nodes().resolveNode(nodeId);
+                if (discoveryNode.getName().equals(nodeName)) {
+                    return shardRouting;
+                }
+            }
+        }
+        return null;
+    }
+
+    protected void assertDocCounts(int expectedDocCount, String... nodeNames) {
+        for (String node : nodeNames) {
+            assertHitCount(client(node).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), expectedDocCount);
+        }
+    }
+
+    protected DiscoveryNode getNodeContainingPrimaryShard() {
+        final ClusterState state = getClusterState();
+        final ShardRouting primaryShard = state.routingTable().index(INDEX_NAME).shard(0).primaryShard();
+        return state.nodes().resolveNode(primaryShard.currentNodeId());
+    }
+
+    /**
+     * Waits until all given nodes have at least the expected docCount.
+     *
+     * @param docCount - Expected Doc count.
+     * @param nodes    - List of node names.
+     */
+    protected void waitForSearchableDocs(long docCount, List<String> nodes) throws Exception {
+        // wait until the replica has the latest segment generation.
+        waitForSearchableDocs(INDEX_NAME, docCount, nodes);
+    }
+
+    public static void waitForSearchableDocs(String indexName, long docCount, List<String> nodes) throws Exception {
+        // wait until the replica has the latest segment generation.
+        assertBusy(() -> {
+            for (String node : nodes) {
+                final SearchResponse response = client(node).prepareSearch(indexName).setSize(0).setPreference("_only_local").get();
+                final long hits = response.getHits().getTotalHits().value;
+                if (hits < docCount) {
+                    fail("Expected search hits on node: " + node + " to be at least " + docCount + " but was: " + hits);
+                }
+            }
+        }, 1, TimeUnit.MINUTES);
+    }
+
+    protected void waitForSearchableDocs(long docCount, String... nodes) throws Exception {
+        waitForSearchableDocs(docCount, Arrays.stream(nodes).collect(Collectors.toList()));
+    }
+
+    protected void verifyStoreContent() throws Exception {
+        assertBusy(() -> {
+            final ClusterState clusterState = getClusterState();
+            for (IndexRoutingTable indexRoutingTable : clusterState.routingTable()) {
+                for (IndexShardRoutingTable shardRoutingTable : indexRoutingTable) {
+                    final ShardRouting primaryRouting = shardRoutingTable.primaryShard();
+                    final String indexName = primaryRouting.getIndexName();
+                    final List<ShardRouting> replicaRouting = shardRoutingTable.replicaShards();
+                    final IndexShard primaryShard = getIndexShard(clusterState, primaryRouting, indexName);
+                    final int primaryDocCount = getDocCountFromShard(primaryShard);
+                    final Map<String, StoreFileMetadata> primarySegmentMetadata = primaryShard.getSegmentMetadataMap();
+                    for (ShardRouting replica : replicaRouting) {
+                        IndexShard replicaShard = getIndexShard(clusterState, replica, indexName);
+                        final Store.RecoveryDiff recoveryDiff = Store.segmentReplicationDiff(
+                            primarySegmentMetadata,
+                            replicaShard.getSegmentMetadataMap()
+                        );
+                        final int replicaDocCount = getDocCountFromShard(replicaShard);
+                        assertEquals("Doc counts should match", primaryDocCount, replicaDocCount);
+                        if (recoveryDiff.missing.isEmpty() == false || recoveryDiff.different.isEmpty() == false) {
+                            fail(
+                                "Expected no missing or different segments between primary and replica but diff was missing: "
+                                    + recoveryDiff.missing
+                                    + " Different: "
+                                    + recoveryDiff.different
+                                    + " Primary Replication Checkpoint : "
+                                    + primaryShard.getLatestReplicationCheckpoint()
+                                    + " Replica Replication Checkpoint: "
+                                    + replicaShard.getLatestReplicationCheckpoint()
+                            );
+                        }
+                        // calls to readCommit will fail if a valid commit point and all its segments are not in the store.
+                        replicaShard.store().readLastCommittedSegmentsInfo();
+                    }
+                }
+            }
+        }, 1, TimeUnit.MINUTES);
+    }
+
+    private int getDocCountFromShard(IndexShard shard) {
+        try (final Engine.Searcher searcher = shard.acquireSearcher("test")) {
+            return searcher.getDirectoryReader().numDocs();
+        }
+    }
+
+    private IndexShard getIndexShard(ClusterState state, ShardRouting routing, String indexName) {
+        return getIndexShard(state.nodes().get(routing.currentNodeId()).getName(), routing.shardId(), indexName);
+    }
+
+    /**
+     * Fetch IndexShard by shardId, multiple shards per node allowed.
+     */
+    protected IndexShard getIndexShard(String node, ShardId shardId, String indexName) {
+        final Index index = resolveIndex(indexName);
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, node);
+        IndexService indexService = indicesService.indexServiceSafe(index);
+        final Optional<Integer> id = indexService.shardIds().stream().filter(sid -> sid == shardId.id()).findFirst();
+        return indexService.getShard(id.get());
+    }
+
+    /**
+     * Fetch IndexShard, assumes only a single shard per node.
+     */
+    protected IndexShard getIndexShard(String node, String indexName) {
+        final Index index = resolveIndex(indexName);
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, node);
+        IndexService indexService = indicesService.indexServiceSafe(index);
+        final Optional<Integer> shardId = indexService.shardIds().stream().findFirst();
+        return indexService.getShard(shardId.get());
+    }
+
+    protected boolean segmentReplicationWithRemoteEnabled() {
+        return IndexMetadata.INDEX_REMOTE_STORE_ENABLED_SETTING.get(indexSettings()).booleanValue();
+    }
+
+    protected Releasable blockReplication(List<String> nodes, CountDownLatch latch) {
+        CountDownLatch pauseReplicationLatch = new CountDownLatch(nodes.size());
+        for (String node : nodes) {
+
+            MockTransportService mockTargetTransportService = ((MockTransportService) internalCluster().getInstance(
+                TransportService.class,
+                node
+            ));
+            mockTargetTransportService.addSendBehavior((connection, requestId, action, request, options) -> {
+                String actionToWaitFor = SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES;
+                if (segmentReplicationWithRemoteEnabled()) {
+                    actionToWaitFor = SegmentReplicationSourceService.Actions.UPDATE_VISIBLE_CHECKPOINT;
+                }
+                if (action.equals(actionToWaitFor)) {
+                    try {
+                        latch.countDown();
+                        pauseReplicationLatch.await();
+                    } catch (InterruptedException e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            });
+        }
+        return () -> {
+            while (pauseReplicationLatch.getCount() > 0) {
+                pauseReplicationLatch.countDown();
+            }
+        };
+    }
+
+    protected void assertReplicaCheckpointUpdated(IndexShard primaryShard) throws Exception {
+        assertBusy(() -> {
+            Set<SegmentReplicationShardStats> groupStats = primaryShard.getReplicationStatsForTrackedReplicas();
+            assertEquals(primaryShard.indexSettings().getNumberOfReplicas(), groupStats.size());
+            for (SegmentReplicationShardStats shardStat : groupStats) {
+                assertEquals(0, shardStat.getCheckpointsBehindCount());
+            }
+        }, 30, TimeUnit.SECONDS);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationClusterSettingIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationClusterSettingIT.java
new file mode 100644
index 0000000000000..a82fd8d845709
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationClusterSettingIT.java
@@ -0,0 +1,126 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.admin.indices.settings.get.GetSettingsRequest;
+import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexModule;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.indices.IndicesService.CLUSTER_SETTING_REPLICATION_TYPE;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationClusterSettingIT extends OpenSearchIntegTestCase {
+
+    protected static final String INDEX_NAME = "test-idx-1";
+    private static final String SYSTEM_INDEX_NAME = ".test-system-index";
+    protected static final int SHARD_COUNT = 1;
+    protected static final int REPLICA_COUNT = 1;
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, SHARD_COUNT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .build();
+    }
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(CLUSTER_SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    public void testIndexReplicationSettingOverridesSegRepClusterSetting() throws Exception {
+        Settings settings = Settings.builder().put(CLUSTER_SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        final String ANOTHER_INDEX = "test-index";
+
+        // Starting two nodes with primary and replica shards respectively.
+        final String primaryNode = internalCluster().startNode(settings);
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder()
+                // we want to override cluster replication setting by passing a index replication setting
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+        ).get();
+        createIndex(ANOTHER_INDEX);
+        ensureYellowAndNoInitializingShards(INDEX_NAME, ANOTHER_INDEX);
+        final String replicaNode = internalCluster().startNode(settings);
+
+        // Randomly close and open index.
+        if (randomBoolean()) {
+            logger.info("--> Closing the index ");
+            client().admin().indices().prepareClose(INDEX_NAME).get();
+
+            logger.info("--> Opening the index");
+            client().admin().indices().prepareOpen(INDEX_NAME).get();
+        }
+        ensureGreen(INDEX_NAME, ANOTHER_INDEX);
+
+        final GetSettingsResponse response = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(INDEX_NAME, ANOTHER_INDEX).includeDefaults(true))
+            .actionGet();
+        assertEquals(response.getSetting(INDEX_NAME, SETTING_REPLICATION_TYPE), ReplicationType.DOCUMENT.toString());
+        assertEquals(response.getSetting(ANOTHER_INDEX, SETTING_REPLICATION_TYPE), ReplicationType.SEGMENT.toString());
+
+        // Verify index setting isSegRepEnabled.
+        Index index = resolveIndex(INDEX_NAME);
+        Index anotherIndex = resolveIndex(ANOTHER_INDEX);
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, primaryNode);
+        assertEquals(indicesService.indexService(index).getIndexSettings().isSegRepEnabled(), false);
+        assertEquals(indicesService.indexService(anotherIndex).getIndexSettings().isSegRepEnabled(), true);
+    }
+
+    public void testIndexReplicationSettingOverridesDocRepClusterSetting() throws Exception {
+        Settings settings = Settings.builder().put(CLUSTER_SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+        final String ANOTHER_INDEX = "test-index";
+        final String primaryNode = internalCluster().startNode(settings);
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder()
+                // we want to override cluster replication setting by passing a index replication setting
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        ).get();
+        createIndex(ANOTHER_INDEX);
+        ensureYellowAndNoInitializingShards(INDEX_NAME, ANOTHER_INDEX);
+        final String replicaNode = internalCluster().startNode(settings);
+        ensureGreen(INDEX_NAME, ANOTHER_INDEX);
+
+        final GetSettingsResponse response = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(INDEX_NAME, ANOTHER_INDEX).includeDefaults(true))
+            .actionGet();
+        assertEquals(response.getSetting(INDEX_NAME, SETTING_REPLICATION_TYPE), ReplicationType.SEGMENT.toString());
+        assertEquals(response.getSetting(ANOTHER_INDEX, SETTING_REPLICATION_TYPE), ReplicationType.DOCUMENT.toString());
+
+        // Verify index setting isSegRepEnabled.
+        Index index = resolveIndex(INDEX_NAME);
+        Index anotherIndex = resolveIndex(ANOTHER_INDEX);
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, primaryNode);
+        assertEquals(indicesService.indexService(index).getIndexSettings().isSegRepEnabled(), true);
+        assertEquals(indicesService.indexService(anotherIndex).getIndexSettings().isSegRepEnabled(), false);
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
new file mode 100644
index 0000000000000..33bc5a8f3afe6
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
@@ -0,0 +1,1780 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import com.carrotsearch.randomizedtesting.RandomizedTest;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.Fields;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.index.StandardDirectoryReader;
+import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.action.admin.indices.alias.Alias;
+import org.opensearch.action.admin.indices.flush.FlushRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.action.get.GetResponse;
+import org.opensearch.action.get.MultiGetRequest;
+import org.opensearch.action.get.MultiGetResponse;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.PitTestsUtil;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchType;
+import org.opensearch.action.support.WriteRequest;
+import org.opensearch.action.termvectors.TermVectorsRequestBuilder;
+import org.opensearch.action.termvectors.TermVectorsResponse;
+import org.opensearch.action.update.UpdateResponse;
+import org.opensearch.client.Requests;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.Preference;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.allocation.command.CancelAllocationCommand;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.index.SegmentReplicationPressureService;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.EngineConfig;
+import org.opensearch.index.engine.NRTReplicationReaderManager;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.recovery.FileChunkRequest;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.node.NodeClosedException;
+import org.opensearch.search.SearchService;
+import org.opensearch.search.builder.PointInTimeBuilder;
+import org.opensearch.search.internal.PitReaderContext;
+import org.opensearch.search.sort.SortOrder;
+import org.opensearch.test.BackgroundIndexer;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.action.search.PitTestsUtil.assertSegments;
+import static org.opensearch.action.search.SearchContextId.decode;
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.index.query.QueryBuilders.boolQuery;
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.index.query.QueryBuilders.matchQuery;
+import static org.opensearch.index.query.QueryBuilders.rangeQuery;
+import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.indices.replication.SegmentReplicationTarget.REPLICATION_PREFIX;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchHits;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationIT extends SegmentReplicationBaseIT {
+
+    @Before
+    private void setup() {
+        internalCluster().startClusterManagerOnlyNode();
+    }
+
+    private static String indexOrAlias() {
+        return randomBoolean() ? INDEX_NAME : "alias";
+    }
+
+    public void testPrimaryStopped_ReplicaPromoted() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        refresh(INDEX_NAME);
+
+        waitForSearchableDocs(1, primary, replica);
+
+        // index another doc but don't refresh, we will ensure this is searchable once replica is promoted.
+        client().prepareIndex(INDEX_NAME).setId("2").setSource("bar", "baz").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+
+        // stop the primary node - we only have one shard on here.
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primary));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+
+        final ShardRouting replicaShardRouting = getShardRoutingForNodeName(replica);
+        assertNotNull(replicaShardRouting);
+        assertTrue(replicaShardRouting + " should be promoted as a primary", replicaShardRouting.primary());
+        final SearchResponse response = client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get();
+        // new primary should have at least the doc count from the first set of segments.
+        assertTrue(response.getHits().getTotalHits().value >= 1);
+
+        // assert we can index into the new primary.
+        client().prepareIndex(INDEX_NAME).setId("3").setSource("bar", "baz").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 3);
+
+        // start another node, index another doc and replicate.
+        String nodeC = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        client().prepareIndex(INDEX_NAME).setId("4").setSource("baz", "baz").get();
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(4, nodeC, replica);
+        verifyStoreContent();
+    }
+
+    public void testRestartPrimary() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        assertEquals(getNodeContainingPrimaryShard().getName(), primary);
+
+        final int initialDocCount = 1;
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        refresh(INDEX_NAME);
+
+        waitForSearchableDocs(initialDocCount, replica, primary);
+
+        internalCluster().restartNode(primary);
+        ensureGreen(INDEX_NAME);
+
+        assertEquals(getNodeContainingPrimaryShard().getName(), replica);
+
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(initialDocCount, replica, primary);
+        verifyStoreContent();
+    }
+
+    public void testCancelPrimaryAllocation() throws Exception {
+        // this test cancels allocation on the primary - promoting the new replica and recreating the former primary as a replica.
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = 1;
+
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        refresh(INDEX_NAME);
+
+        waitForSearchableDocs(initialDocCount, replica, primary);
+
+        final IndexShard indexShard = getIndexShard(primary, INDEX_NAME);
+        client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new CancelAllocationCommand(INDEX_NAME, indexShard.shardId().id(), primary, true))
+            .execute()
+            .actionGet();
+        ensureGreen(INDEX_NAME);
+
+        assertEquals(getNodeContainingPrimaryShard().getName(), replica);
+
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(initialDocCount, replica, primary);
+        verifyStoreContent();
+    }
+
+    public void testReplicationAfterPrimaryRefreshAndFlush() throws Exception {
+        final String nodeA = internalCluster().startDataOnlyNode();
+        final String nodeB = internalCluster().startDataOnlyNode();
+        final Settings settings = Settings.builder()
+            .put(indexSettings())
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), randomFrom(new ArrayList<>(CODECS) {
+                {
+                    add(CodecService.LUCENE_DEFAULT_CODEC);
+                }
+            }))
+            .build();
+        createIndex(INDEX_NAME, settings);
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = scaledRandomIntBetween(0, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, nodeA, nodeB);
+
+            final int additionalDocCount = scaledRandomIntBetween(0, 200);
+            final int expectedHitCount = initialDocCount + additionalDocCount;
+            indexer.start(additionalDocCount);
+            waitForDocs(expectedHitCount, indexer);
+
+            flushAndRefresh(INDEX_NAME);
+            waitForSearchableDocs(expectedHitCount, nodeA, nodeB);
+
+            ensureGreen(INDEX_NAME);
+            verifyStoreContent();
+        }
+    }
+
+    public void testIndexReopenClose() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        final String replica = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = scaledRandomIntBetween(100, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            flush(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, primary, replica);
+        }
+        logger.info("--> Closing the index ");
+        client().admin().indices().prepareClose(INDEX_NAME).get();
+
+        logger.info("--> Opening the index");
+        client().admin().indices().prepareOpen(INDEX_NAME).get();
+
+        ensureGreen(INDEX_NAME);
+        waitForSearchableDocs(initialDocCount, primary, replica);
+        verifyStoreContent();
+    }
+
+    public void testScrollWithConcurrentIndexAndSearch() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        final String replica = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        final List<ActionFuture<IndexResponse>> pendingIndexResponses = new ArrayList<>();
+        final List<ActionFuture<SearchResponse>> pendingSearchResponse = new ArrayList<>();
+        final int searchCount = randomIntBetween(10, 20);
+        final WriteRequest.RefreshPolicy refreshPolicy = randomFrom(WriteRequest.RefreshPolicy.values());
+
+        for (int i = 0; i < searchCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+            flush(INDEX_NAME);
+            forceMerge();
+        }
+
+        final SearchResponse searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .setIndices(INDEX_NAME)
+            .setRequestCache(false)
+            .setScroll(TimeValue.timeValueDays(1))
+            .setSize(10)
+            .get();
+
+        for (int i = searchCount; i < searchCount * 2; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+        flush(INDEX_NAME);
+        forceMerge();
+        client().prepareClearScroll().addScrollId(searchResponse.getScrollId()).get();
+
+        assertBusy(() -> {
+            client().admin().indices().prepareRefresh().execute().actionGet();
+            assertTrue(pendingIndexResponses.stream().allMatch(ActionFuture::isDone));
+            assertTrue(pendingSearchResponse.stream().allMatch(ActionFuture::isDone));
+        }, 1, TimeUnit.MINUTES);
+        verifyStoreContent();
+        waitForSearchableDocs(INDEX_NAME, 2 * searchCount, List.of(primary, replica));
+    }
+
+    public void testMultipleShards() throws Exception {
+        Settings indexSettings = Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        final String nodeA = internalCluster().startDataOnlyNode();
+        final String nodeB = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME, indexSettings);
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = scaledRandomIntBetween(1, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, nodeA, nodeB);
+
+            final int additionalDocCount = scaledRandomIntBetween(0, 200);
+            final int expectedHitCount = initialDocCount + additionalDocCount;
+            indexer.start(additionalDocCount);
+            waitForDocs(expectedHitCount, indexer);
+
+            flushAndRefresh(INDEX_NAME);
+            waitForSearchableDocs(expectedHitCount, nodeA, nodeB);
+
+            ensureGreen(INDEX_NAME);
+            verifyStoreContent();
+        }
+    }
+
+    public void testReplicationAfterForceMerge() throws Exception {
+        final String nodeA = internalCluster().startDataOnlyNode();
+        final String nodeB = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = scaledRandomIntBetween(0, 200);
+        final int additionalDocCount = scaledRandomIntBetween(0, 200);
+        final int expectedHitCount = initialDocCount + additionalDocCount;
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+
+            flush(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, nodeA, nodeB);
+
+            // Index a second set of docs so we can merge into one segment.
+            indexer.start(additionalDocCount);
+            waitForDocs(expectedHitCount, indexer);
+            waitForSearchableDocs(expectedHitCount, nodeA, nodeB);
+
+            // Force a merge here so that the in memory SegmentInfos does not reference old segments on disk.
+            client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(false).get();
+            refresh(INDEX_NAME);
+            verifyStoreContent();
+        }
+    }
+
+    /**
+     * This test verifies that segment replication does not fail for closed indices
+     */
+    public void testClosedIndices() {
+        List<String> nodes = new ArrayList<>();
+        // start 1st node so that it contains the primary
+        nodes.add(internalCluster().startDataOnlyNode());
+        createIndex(INDEX_NAME, super.indexSettings());
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        // start 2nd node so that it contains the replica
+        nodes.add(internalCluster().startDataOnlyNode());
+        ensureGreen(INDEX_NAME);
+
+        logger.info("--> Close index");
+        assertAcked(client().admin().indices().prepareClose(INDEX_NAME));
+
+        logger.info("--> waiting for allocation to have shards assigned");
+        waitForRelocation(ClusterHealthStatus.GREEN);
+    }
+
+    /**
+     * This test validates the primary node drop does not result in shard failure on replica.
+     * @throws Exception when issue is encountered
+     */
+    public void testNodeDropWithOngoingReplication() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                .put("index.refresh_interval", -1)
+                .build()
+        );
+        ensureYellow(INDEX_NAME);
+        final String replicaNode = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        ClusterState state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        // Get replica allocation id
+        final String replicaAllocationId = state.routingTable()
+            .index(INDEX_NAME)
+            .shardsWithState(ShardRoutingState.STARTED)
+            .stream()
+            .filter(routing -> routing.primary() == false)
+            .findFirst()
+            .get()
+            .allocationId()
+            .getId();
+        DiscoveryNode primaryDiscovery = state.nodes().resolveNode(primaryNode);
+
+        CountDownLatch blockFileCopy = new CountDownLatch(1);
+        MockTransportService primaryTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            primaryNode
+        ));
+        primaryTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, replicaNode),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationTargetService.Actions.FILE_CHUNK)) {
+                    FileChunkRequest req = (FileChunkRequest) request;
+                    logger.debug("file chunk [{}] lastChunk: {}", req, req.lastChunk());
+                    if (req.name().endsWith("cfs") && req.lastChunk()) {
+                        try {
+                            blockFileCopy.await();
+                        } catch (InterruptedException e) {
+                            throw new RuntimeException(e);
+                        }
+                        throw new NodeClosedException(primaryDiscovery);
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+        }
+        // Refresh, this should trigger round of segment replication
+        refresh(INDEX_NAME);
+        blockFileCopy.countDown();
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNode));
+        ensureYellow(INDEX_NAME);
+        assertBusy(() -> { assertDocCounts(docCount, replicaNode); });
+        state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        // replica now promoted as primary should have same allocation id
+        final String currentAllocationID = state.routingTable()
+            .index(INDEX_NAME)
+            .shardsWithState(ShardRoutingState.STARTED)
+            .stream()
+            .filter(routing -> routing.primary())
+            .findFirst()
+            .get()
+            .allocationId()
+            .getId();
+        assertEquals(currentAllocationID, replicaAllocationId);
+    }
+
+    public void testCancellation() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1).build());
+        ensureYellow(INDEX_NAME);
+
+        final String replicaNode = internalCluster().startDataOnlyNode();
+
+        final SegmentReplicationSourceService segmentReplicationSourceService = internalCluster().getInstance(
+            SegmentReplicationSourceService.class,
+            primaryNode
+        );
+        final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+
+        CountDownLatch latch = new CountDownLatch(1);
+
+        MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            primaryNode
+        ));
+        mockTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, replicaNode),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationTargetService.Actions.FILE_CHUNK)) {
+                    FileChunkRequest req = (FileChunkRequest) request;
+                    logger.debug("file chunk [{}] lastChunk: {}", req, req.lastChunk());
+                    if (req.name().endsWith("cfs") && req.lastChunk()) {
+                        try {
+                            latch.await();
+                        } catch (InterruptedException e) {
+                            throw new RuntimeException(e);
+                        }
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+
+        final int docCount = scaledRandomIntBetween(0, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(docCount);
+            waitForDocs(docCount, indexer);
+
+            flush(INDEX_NAME);
+        }
+        segmentReplicationSourceService.beforeIndexShardClosed(primaryShard.shardId(), primaryShard, indexSettings());
+        latch.countDown();
+        assertDocCounts(docCount, primaryNode);
+    }
+
+    public void testStartReplicaAfterPrimaryIndexesDocs() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0).build());
+        ensureGreen(INDEX_NAME);
+
+        // Index a doc to create the first set of segments. _s1.si
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").get();
+        // Flush segments to disk and create a new commit point (Primary: segments_3, _s1.si)
+        flushAndRefresh(INDEX_NAME);
+        assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 1);
+
+        // Index to create another segment
+        client().prepareIndex(INDEX_NAME).setId("2").setSource("foo", "bar").get();
+
+        // Force a merge here so that the in memory SegmentInfos does not reference old segments on disk.
+        client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(false).get();
+        refresh(INDEX_NAME);
+
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings(INDEX_NAME)
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+        );
+        final String replicaNode = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 2);
+        assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 2);
+
+        client().prepareIndex(INDEX_NAME).setId("3").setSource("foo", "bar").get();
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(3, primaryNode, replicaNode);
+        assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 3);
+        assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 3);
+        verifyStoreContent();
+    }
+
+    public void testDeleteOperations() throws Exception {
+        final String nodeA = internalCluster().startDataOnlyNode();
+        final String nodeB = internalCluster().startDataOnlyNode();
+
+        createIndex(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        final int initialDocCount = scaledRandomIntBetween(1, 20);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, nodeA, nodeB);
+
+            final int additionalDocCount = scaledRandomIntBetween(0, 20);
+            final int expectedHitCount = initialDocCount + additionalDocCount;
+            indexer.start(additionalDocCount);
+            waitForDocs(expectedHitCount, indexer);
+            waitForSearchableDocs(expectedHitCount, nodeA, nodeB);
+
+            ensureGreen(INDEX_NAME);
+
+            Set<String> ids = indexer.getIds();
+            assertFalse(ids.isEmpty());
+            String id = ids.toArray()[0].toString();
+            client(nodeA).prepareDelete(INDEX_NAME, id).setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+
+            refresh(INDEX_NAME);
+            waitForSearchableDocs(expectedHitCount - 1, nodeA, nodeB);
+            verifyStoreContent();
+        }
+    }
+
+    /**
+     * This tests that the max seqNo we send to replicas is accurate and that after failover
+     * the new primary starts indexing from the correct maxSeqNo and replays the correct count of docs
+     * from xlog.
+     */
+    public void testReplicationPostDeleteAndForceMerge() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        final int initialDocCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < initialDocCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(String.valueOf(i)).setSource("foo", "bar").get();
+        }
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(initialDocCount, primary, replica);
+
+        final int deletedDocCount = randomIntBetween(10, initialDocCount);
+        for (int i = 0; i < deletedDocCount; i++) {
+            client(primary).prepareDelete(INDEX_NAME, String.valueOf(i)).setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        }
+        client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(false).get();
+
+        // randomly flush here after the force merge to wipe any old segments.
+        if (randomBoolean()) {
+            flush(INDEX_NAME);
+        }
+
+        final IndexShard primaryShard = getIndexShard(primary, INDEX_NAME);
+        final IndexShard replicaShard = getIndexShard(replica, INDEX_NAME);
+        assertBusy(
+            () -> assertEquals(
+                primaryShard.getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                replicaShard.getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            )
+        );
+
+        // add some docs to the xlog and drop primary.
+        final int additionalDocs = randomIntBetween(1, 50);
+        for (int i = initialDocCount; i < initialDocCount + additionalDocs; i++) {
+            client().prepareIndex(INDEX_NAME).setId(String.valueOf(i)).setSource("foo", "bar").get();
+        }
+        // Drop the primary and wait until replica is promoted.
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primary));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+
+        final ShardRouting replicaShardRouting = getShardRoutingForNodeName(replica);
+        assertNotNull(replicaShardRouting);
+        assertTrue(replicaShardRouting + " should be promoted as a primary", replicaShardRouting.primary());
+        refresh(INDEX_NAME);
+        final long expectedHitCount = initialDocCount + additionalDocs - deletedDocCount;
+        assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), expectedHitCount);
+
+        int expectedMaxSeqNo = initialDocCount + deletedDocCount + additionalDocs - 1;
+        assertEquals(expectedMaxSeqNo, replicaShard.seqNoStats().getMaxSeqNo());
+
+        // index another doc.
+        client().prepareIndex(INDEX_NAME).setId(String.valueOf(expectedMaxSeqNo + 1)).setSource("another", "doc").get();
+        refresh(INDEX_NAME);
+        assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), expectedHitCount + 1);
+    }
+
+    public void testUpdateOperations() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellow(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = scaledRandomIntBetween(0, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, asList(primary, replica));
+
+            final int additionalDocCount = scaledRandomIntBetween(0, 200);
+            final int expectedHitCount = initialDocCount + additionalDocCount;
+            indexer.start(additionalDocCount);
+            waitForDocs(expectedHitCount, indexer);
+            waitForSearchableDocs(expectedHitCount, asList(primary, replica));
+
+            Set<String> ids = indexer.getIds();
+            String id = ids.toArray()[0].toString();
+            UpdateResponse updateResponse = client(primary).prepareUpdate(INDEX_NAME, id)
+                .setDoc(Requests.INDEX_CONTENT_TYPE, "foo", "baz")
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL)
+                .get();
+            assertFalse("request shouldn't have forced a refresh", updateResponse.forcedRefresh());
+            assertEquals(2, updateResponse.getVersion());
+
+            refresh(INDEX_NAME);
+
+            verifyStoreContent();
+            assertSearchHits(client(primary).prepareSearch(INDEX_NAME).setQuery(matchQuery("foo", "baz")).get(), id);
+            assertSearchHits(client(replica).prepareSearch(INDEX_NAME).setQuery(matchQuery("foo", "baz")).get(), id);
+        }
+    }
+
+    public void testDropPrimaryDuringReplication() throws Exception {
+        final int replica_count = 6;
+        final Settings settings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, replica_count)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME, settings);
+        final List<String> dataNodes = internalCluster().startDataOnlyNodes(6);
+        ensureGreen(INDEX_NAME);
+
+        int initialDocCount = scaledRandomIntBetween(100, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+            // don't wait for replication to complete, stop the primary immediately.
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNode));
+            ensureYellow(INDEX_NAME);
+
+            // start another replica.
+            dataNodes.add(internalCluster().startDataOnlyNode());
+            ensureGreen(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount, dataNodes);
+
+            // index another doc and refresh - without this the new replica won't catch up.
+            String docId = String.valueOf(initialDocCount + 1);
+            client().prepareIndex(INDEX_NAME).setId(docId).setSource("foo", "bar").get();
+
+            flushAndRefresh(INDEX_NAME);
+            waitForSearchableDocs(initialDocCount + 1, dataNodes);
+            verifyStoreContent();
+        }
+    }
+
+    public void testReplicaHasDiffFilesThanPrimary() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1).build());
+        ensureYellow(INDEX_NAME);
+        final String replicaNode = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final IndexShard replicaShard = getIndexShard(replicaNode, INDEX_NAME);
+        IndexWriterConfig iwc = newIndexWriterConfig().setOpenMode(IndexWriterConfig.OpenMode.APPEND);
+
+        // create a doc to index
+        int numDocs = 2 + random().nextInt(100);
+
+        List<Document> docs = new ArrayList<>();
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
+            doc.add(
+                new TextField(
+                    "body",
+                    TestUtil.randomRealisticUnicodeString(random()),
+                    random().nextBoolean() ? Field.Store.YES : Field.Store.NO
+                )
+            );
+            doc.add(new SortedDocValuesField("dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
+            docs.add(doc);
+        }
+        // create some segments on the replica before copy.
+        try (IndexWriter writer = new IndexWriter(replicaShard.store().directory(), iwc)) {
+            for (Document d : docs) {
+                writer.addDocument(d);
+            }
+            writer.flush();
+            writer.commit();
+        }
+
+        final SegmentInfos segmentInfos = SegmentInfos.readLatestCommit(replicaShard.store().directory());
+        replicaShard.finalizeReplication(segmentInfos);
+        ensureYellow(INDEX_NAME);
+
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+            // Refresh, this should trigger round of segment replication
+            refresh(INDEX_NAME);
+        }
+        ensureGreen(INDEX_NAME);
+        waitForSearchableDocs(docCount, primaryNode, replicaNode);
+        verifyStoreContent();
+        final IndexShard replicaAfterFailure = getIndexShard(replicaNode, INDEX_NAME);
+        assertNotEquals(replicaAfterFailure.routingEntry().allocationId().getId(), replicaShard.routingEntry().allocationId().getId());
+    }
+
+    public void testPressureServiceStats() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellow(INDEX_NAME);
+        final String replicaNode = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        int initialDocCount = scaledRandomIntBetween(100, 200);
+        try (
+            BackgroundIndexer indexer = new BackgroundIndexer(
+                INDEX_NAME,
+                "_doc",
+                client(),
+                -1,
+                RandomizedTest.scaledRandomIntBetween(2, 5),
+                false,
+                random()
+            )
+        ) {
+            indexer.start(initialDocCount);
+            waitForDocs(initialDocCount, indexer);
+            refresh(INDEX_NAME);
+
+            // get shard references.
+            final IndexShard primaryShard = getIndexShard(primaryNode, INDEX_NAME);
+            final IndexShard replicaShard = getIndexShard(replicaNode, INDEX_NAME);
+            logger.info("Replica aid {}", replicaShard.routingEntry().allocationId());
+            logger.info("former primary aid {}", primaryShard.routingEntry().allocationId());
+
+            // fetch pressure stats from the Primary's Node.
+            SegmentReplicationPressureService pressureService = internalCluster().getInstance(
+                SegmentReplicationPressureService.class,
+                primaryNode
+            );
+
+            // Fetch pressure stats from the Replica's Node we will assert replica node returns nothing until it is promoted.
+            SegmentReplicationPressureService replicaNode_service = internalCluster().getInstance(
+                SegmentReplicationPressureService.class,
+                replicaNode
+            );
+
+            final Map<ShardId, SegmentReplicationPerGroupStats> shardStats = pressureService.nodeStats().getShardStats();
+            assertEquals("We should have stats returned for the replication group", 1, shardStats.size());
+
+            SegmentReplicationPerGroupStats groupStats = shardStats.get(primaryShard.shardId());
+            Set<SegmentReplicationShardStats> replicaStats = groupStats.getReplicaStats();
+            assertAllocationIdsInReplicaShardStats(Set.of(replicaShard.routingEntry().allocationId().getId()), replicaStats);
+
+            assertTrue(replicaNode_service.nodeStats().getShardStats().isEmpty());
+
+            // drop the primary, this won't hand off pressure stats between old/new primary.
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNode));
+            ensureYellowAndNoInitializingShards(INDEX_NAME);
+
+            assertTrue("replica should be promoted as a primary", replicaShard.routingEntry().primary());
+            assertEquals(
+                "We should have stats returned for the replication group",
+                1,
+                replicaNode_service.nodeStats().getShardStats().size()
+            );
+            // after the primary is dropped and replica is promoted we won't have a replica assigned yet, so stats per replica should return
+            // empty.
+            replicaStats = replicaNode_service.nodeStats().getShardStats().get(primaryShard.shardId()).getReplicaStats();
+            assertTrue(replicaStats.isEmpty());
+
+            // start another replica.
+            String replicaNode_2 = internalCluster().startDataOnlyNode();
+            ensureGreen(INDEX_NAME);
+            final IndexShard secondReplicaShard = getIndexShard(replicaNode_2, INDEX_NAME);
+            final String second_replica_aid = secondReplicaShard.routingEntry().allocationId().getId();
+            waitForSearchableDocs(initialDocCount, replicaNode_2);
+
+            assertEquals(
+                "We should have stats returned for the replication group",
+                1,
+                replicaNode_service.nodeStats().getShardStats().size()
+            );
+            replicaStats = replicaNode_service.nodeStats().getShardStats().get(replicaShard.shardId()).getReplicaStats();
+            assertAllocationIdsInReplicaShardStats(Set.of(second_replica_aid), replicaStats);
+            final SegmentReplicationShardStats replica_entry = replicaStats.stream().findFirst().get();
+            assertEquals(replica_entry.getCheckpointsBehindCount(), 0);
+
+            // test a checkpoint without any new segments
+            flush(INDEX_NAME);
+            assertBusy(() -> {
+                assertEquals(1, replicaNode_service.nodeStats().getShardStats().size());
+                final Set<SegmentReplicationShardStats> shardStatsSet = replicaNode_service.nodeStats()
+                    .getShardStats()
+                    .get(replicaShard.shardId())
+                    .getReplicaStats();
+                assertAllocationIdsInReplicaShardStats(Set.of(second_replica_aid), shardStatsSet);
+                final SegmentReplicationShardStats stats = shardStatsSet.stream().findFirst().get();
+                assertEquals(0, stats.getCheckpointsBehindCount());
+            });
+        }
+    }
+
+    private void assertAllocationIdsInReplicaShardStats(Set<String> expected, Set<SegmentReplicationShardStats> replicaStats) {
+        assertEquals(expected, replicaStats.stream().map(SegmentReplicationShardStats::getAllocationId).collect(Collectors.toSet()));
+    }
+
+    /**
+     * Tests a scroll query on the replica
+     * @throws Exception when issue is encountered
+     */
+    public void testScrollCreatedOnReplica() throws Exception {
+        // create the cluster with one primary node containing primary shard and replica node containing replica shard
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        // index 100 docs
+        for (int i = 0; i < 100; i++) {
+            client().prepareIndex(INDEX_NAME)
+                .setId(String.valueOf(i))
+                .setSource(jsonBuilder().startObject().field("field", i).endObject())
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .get();
+            refresh(INDEX_NAME);
+        }
+        assertBusy(
+            () -> assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            )
+        );
+        final IndexShard replicaShard = getIndexShard(replica, INDEX_NAME);
+        final Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> tuple = replicaShard.getLatestSegmentInfosAndCheckpoint();
+        final Collection<String> snapshottedSegments;
+        try (final GatedCloseable<SegmentInfos> closeable = tuple.v1()) {
+            snapshottedSegments = closeable.get().files(false);
+        }
+        // opens a scrolled query before a flush is called.
+        // this is for testing scroll segment consistency between refresh and flush
+        SearchResponse searchResponse = client(replica).prepareSearch()
+            .setQuery(matchAllQuery())
+            .setIndices(INDEX_NAME)
+            .setRequestCache(false)
+            .setPreference("_only_local")
+            .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
+            .addSort("field", SortOrder.ASC)
+            .setSize(10)
+            .setScroll(TimeValue.timeValueDays(1))
+            .get();
+
+        // force call flush
+        flush(INDEX_NAME);
+
+        for (int i = 3; i < 50; i++) {
+            client().prepareDelete(INDEX_NAME, String.valueOf(i)).setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+            refresh(INDEX_NAME);
+            if (randomBoolean()) {
+                client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(true).get();
+                flush(INDEX_NAME);
+            }
+        }
+        assertBusy(() -> {
+            assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        });
+
+        client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(true).get();
+        assertBusy(() -> {
+            assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        });
+        // Test stats
+        logger.info("--> Collect all scroll query hits");
+        long scrollHits = 0;
+        do {
+            scrollHits += searchResponse.getHits().getHits().length;
+            searchResponse = client(replica).prepareSearchScroll(searchResponse.getScrollId()).setScroll(TimeValue.timeValueDays(1)).get();
+            assertAllSuccessful(searchResponse);
+        } while (searchResponse.getHits().getHits().length > 0);
+
+        List<String> currentFiles = List.of(replicaShard.store().directory().listAll());
+        assertTrue("Files should be preserved", currentFiles.containsAll(snapshottedSegments));
+
+        client(replica).prepareClearScroll().addScrollId(searchResponse.getScrollId()).get();
+
+        currentFiles = List.of(replicaShard.store().directory().listAll());
+        assertFalse("Files should be cleaned up post scroll clear request", currentFiles.containsAll(snapshottedSegments));
+        assertEquals(100, scrollHits);
+    }
+
+    /**
+     * Tests that when scroll query is cleared, it does not delete the temporary replication files, which are part of
+     * ongoing round of segment replication
+     *
+     * @throws Exception when issue is encountered
+     */
+    public void testScrollWithOngoingSegmentReplication() throws Exception {
+        // this test stubs transport calls specific to node-node replication.
+        assumeFalse(
+            "Skipping the test as its not compatible with segment replication with remote store.",
+            segmentReplicationWithRemoteEnabled()
+        );
+
+        // create the cluster with one primary node containing primary shard and replica node containing replica shard
+        final String primary = internalCluster().startDataOnlyNode();
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder()
+                // we want to control refreshes
+                .put("index.refresh_interval", -1)
+        ).get();
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final int initialDocCount = 10;
+        final int finalDocCount = 20;
+        for (int i = 0; i < initialDocCount; i++) {
+            client().prepareIndex(INDEX_NAME)
+                .setId(String.valueOf(i))
+                .setSource(jsonBuilder().startObject().field("field", i).endObject())
+                .get();
+        }
+        // catch up replica with primary
+        refresh(INDEX_NAME);
+        assertBusy(
+            () -> assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            )
+        );
+        logger.info("--> Create scroll query");
+        // opens a scrolled query before a flush is called.
+        SearchResponse searchResponse = client(replica).prepareSearch()
+            .setQuery(matchAllQuery())
+            .setIndices(INDEX_NAME)
+            .setRequestCache(false)
+            .setPreference("_only_local")
+            .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
+            .addSort("field", SortOrder.ASC)
+            .setSize(10)
+            .setScroll(TimeValue.timeValueDays(1))
+            .get();
+
+        // force call flush
+        flush(INDEX_NAME);
+
+        // Index more documents
+        for (int i = initialDocCount; i < finalDocCount; i++) {
+            client().prepareIndex(INDEX_NAME)
+                .setId(String.valueOf(i))
+                .setSource(jsonBuilder().startObject().field("field", i).endObject())
+                .get();
+        }
+        // Block file copy operation to ensure replica has few temporary replication files
+        CountDownLatch blockFileCopy = new CountDownLatch(1);
+        CountDownLatch waitForFileCopy = new CountDownLatch(1);
+        MockTransportService primaryTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            primary
+        ));
+        primaryTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, replica),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationTargetService.Actions.FILE_CHUNK)) {
+                    FileChunkRequest req = (FileChunkRequest) request;
+                    logger.debug("file chunk [{}] lastChunk: {}", req, req.lastChunk());
+                    if (req.name().endsWith("cfs") && req.lastChunk()) {
+                        try {
+                            waitForFileCopy.countDown();
+                            logger.info("--> Waiting for file copy");
+                            blockFileCopy.await();
+                        } catch (InterruptedException e) {
+                            throw new RuntimeException(e);
+                        }
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+
+        // perform refresh to start round of segment replication
+        refresh(INDEX_NAME);
+
+        // wait for segrep to start and copy temporary files
+        waitForFileCopy.await();
+
+        final IndexShard replicaShard = getIndexShard(replica, INDEX_NAME);
+        // Wait until replica has written a tmp file to disk.
+        List<String> temporaryFiles = new ArrayList<>();
+        assertBusy(() -> {
+            // verify replica contains temporary files
+            temporaryFiles.addAll(
+                Arrays.stream(replicaShard.store().directory().listAll())
+                    .filter(fileName -> fileName.startsWith(REPLICATION_PREFIX))
+                    .collect(Collectors.toList())
+            );
+            logger.info("--> temporaryFiles {}", temporaryFiles);
+            assertTrue(temporaryFiles.size() > 0);
+        });
+
+        // Clear scroll query, this should clean up files on replica
+        client(replica).prepareClearScroll().addScrollId(searchResponse.getScrollId()).get();
+
+        // verify temporary files still exist
+        List<String> temporaryFilesPostClear = Arrays.stream(replicaShard.store().directory().listAll())
+            .filter(fileName -> fileName.startsWith(REPLICATION_PREFIX))
+            .collect(Collectors.toList());
+        logger.info("--> temporaryFilesPostClear {}", temporaryFilesPostClear);
+
+        // Unblock segment replication
+        blockFileCopy.countDown();
+
+        assertTrue(temporaryFilesPostClear.containsAll(temporaryFiles));
+
+        // wait for replica to catch up and verify doc count
+        assertBusy(() -> {
+            assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        });
+        verifyStoreContent();
+        waitForSearchableDocs(finalDocCount, primary, replica);
+    }
+
+    public void testPitCreatedOnReplica() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        client().prepareIndex(INDEX_NAME)
+            .setId("1")
+            .setSource("foo", randomInt())
+            .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+            .get();
+        refresh(INDEX_NAME);
+
+        client().prepareIndex(INDEX_NAME)
+            .setId("2")
+            .setSource("foo", randomInt())
+            .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+            .get();
+        for (int i = 3; i < 100; i++) {
+            client().prepareIndex(INDEX_NAME)
+                .setId(String.valueOf(i))
+                .setSource("foo", randomInt())
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .get();
+            refresh(INDEX_NAME);
+        }
+        // wait until replication finishes, then make the pit request.
+        assertBusy(
+            () -> assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            )
+        );
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), false);
+        request.setPreference("_only_local");
+        request.setIndices(new String[] { INDEX_NAME });
+        ActionFuture<CreatePitResponse> execute = client(replica).execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        SearchResponse searchResponse = client(replica).prepareSearch(INDEX_NAME)
+            .setSize(10)
+            .setPreference("_only_local")
+            .setRequestCache(false)
+            .addSort("foo", SortOrder.ASC)
+            .searchAfter(new Object[] { 30 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+            .get();
+        assertEquals(1, searchResponse.getSuccessfulShards());
+        assertEquals(1, searchResponse.getTotalShards());
+        FlushRequest flushRequest = Requests.flushRequest(INDEX_NAME);
+        client().admin().indices().flush(flushRequest).get();
+        final IndexShard replicaShard = getIndexShard(replica, INDEX_NAME);
+
+        // fetch the segments snapshotted when the reader context was created.
+        Collection<String> snapshottedSegments;
+        SearchService searchService = internalCluster().getInstance(SearchService.class, replica);
+        NamedWriteableRegistry registry = internalCluster().getInstance(NamedWriteableRegistry.class, replica);
+        final PitReaderContext pitReaderContext = searchService.getPitReaderContext(
+            decode(registry, pitResponse.getId()).shards().get(replicaShard.routingEntry().shardId()).getSearchContextId()
+        );
+        try (final Engine.Searcher searcher = pitReaderContext.acquireSearcher("test")) {
+            final StandardDirectoryReader standardDirectoryReader = NRTReplicationReaderManager.unwrapStandardReader(
+                (OpenSearchDirectoryReader) searcher.getDirectoryReader()
+            );
+            final SegmentInfos infos = standardDirectoryReader.getSegmentInfos();
+            snapshottedSegments = infos.files(false);
+        }
+
+        flush(INDEX_NAME);
+        for (int i = 101; i < 200; i++) {
+            client().prepareIndex(INDEX_NAME)
+                .setId(String.valueOf(i))
+                .setSource("foo", randomInt())
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .get();
+            refresh(INDEX_NAME);
+            if (randomBoolean()) {
+                client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(true).get();
+                flush(INDEX_NAME);
+            }
+        }
+        assertBusy(() -> {
+            assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        });
+
+        client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(true).get();
+        assertBusy(() -> {
+            assertEquals(
+                getIndexShard(primary, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion(),
+                getIndexShard(replica, INDEX_NAME).getLatestReplicationCheckpoint().getSegmentInfosVersion()
+            );
+        });
+        // Test stats
+        IndicesStatsRequest indicesStatsRequest = new IndicesStatsRequest();
+        indicesStatsRequest.indices(INDEX_NAME);
+        indicesStatsRequest.all();
+        IndicesStatsResponse indicesStatsResponse = client().admin().indices().stats(indicesStatsRequest).get();
+        long pitCurrent = indicesStatsResponse.getIndex(INDEX_NAME).getTotal().search.getTotal().getPitCurrent();
+        long openContexts = indicesStatsResponse.getIndex(INDEX_NAME).getTotal().search.getOpenContexts();
+        assertEquals(1, pitCurrent);
+        assertEquals(1, openContexts);
+        SearchResponse resp = client(replica).prepareSearch(INDEX_NAME)
+            .setSize(10)
+            .setPreference("_only_local")
+            .addSort("foo", SortOrder.ASC)
+            .searchAfter(new Object[] { 30 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+            .setRequestCache(false)
+            .get();
+        PitTestsUtil.assertUsingGetAllPits(client(replica), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, INDEX_NAME, 1, client(replica), pitResponse.getId());
+
+        List<String> currentFiles = List.of(replicaShard.store().directory().listAll());
+        assertTrue("Files should be preserved", currentFiles.containsAll(snapshottedSegments));
+
+        // delete the PIT
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitResponse.getId());
+        client().execute(DeletePitAction.INSTANCE, deletePITRequest).actionGet();
+
+        currentFiles = List.of(replicaShard.store().directory().listAll());
+        assertFalse("Files should be cleaned up", currentFiles.containsAll(snapshottedSegments));
+    }
+
+    /**
+     * This tests that if a primary receives docs while a replica is performing round of segrep during recovery
+     * the replica will catch up to latest checkpoint once recovery completes without requiring an additional primary refresh/flush.
+     */
+    public void testPrimaryReceivesDocsDuringReplicaRecovery() throws Exception {
+        final List<String> nodes = new ArrayList<>();
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        nodes.add(primaryNode);
+        final Settings settings = Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0).build();
+        createIndex(INDEX_NAME, settings);
+        ensureGreen(INDEX_NAME);
+        // start a replica node, initially will be empty with no shard assignment.
+        final String replicaNode = internalCluster().startDataOnlyNode();
+        nodes.add(replicaNode);
+
+        // index a doc.
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", randomInt()).get();
+        refresh(INDEX_NAME);
+
+        CountDownLatch latch = new CountDownLatch(1);
+        // block replication
+        try (final Releasable ignored = blockReplication(List.of(replicaNode), latch)) {
+            // update to add replica, initiating recovery, this will get stuck at last step
+            assertAcked(
+                client().admin()
+                    .indices()
+                    .prepareUpdateSettings(INDEX_NAME)
+                    .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+            );
+            ensureYellow(INDEX_NAME);
+            // index another doc while blocked, this would not get replicated to replica.
+            client().prepareIndex(INDEX_NAME).setId("2").setSource("foo2", randomInt()).get();
+            refresh(INDEX_NAME);
+        }
+        ensureGreen(INDEX_NAME);
+        waitForSearchableDocs(2, nodes);
+    }
+
+    public void testIndexWhileRecoveringReplica() throws Exception {
+        final String primaryNode = internalCluster().startDataOnlyNode();
+        assertAcked(
+            prepareCreate(INDEX_NAME).setMapping(
+                jsonBuilder().startObject()
+                    .startObject("_routing")
+                    .field("required", true)
+                    .endObject()
+                    .startObject("properties")
+                    .startObject("online")
+                    .field("type", "boolean")
+                    .endObject()
+                    .startObject("ts")
+                    .field("type", "date")
+                    .field("ignore_malformed", false)
+                    .field("format", "epoch_millis")
+                    .endObject()
+                    .startObject("bs")
+                    .field("type", "keyword")
+                    .endObject()
+                    .endObject()
+                    .endObject()
+            )
+        );
+        ensureYellow(INDEX_NAME);
+        final String replicaNode = internalCluster().startDataOnlyNode();
+
+        client().prepareIndex(INDEX_NAME)
+            .setId("1")
+            .setRouting("Y")
+            .setSource("online", false, "bs", "Y", "ts", System.currentTimeMillis() - 100, "type", "s")
+            .get();
+        client().prepareIndex(INDEX_NAME)
+            .setId("2")
+            .setRouting("X")
+            .setSource("online", true, "bs", "X", "ts", System.currentTimeMillis() - 10000000, "type", "s")
+            .get();
+        client().prepareIndex(INDEX_NAME)
+            .setId("3")
+            .setRouting(randomAlphaOfLength(2))
+            .setSource("online", false, "ts", System.currentTimeMillis() - 100, "type", "bs")
+            .get();
+        client().prepareIndex(INDEX_NAME)
+            .setId("4")
+            .setRouting(randomAlphaOfLength(2))
+            .setSource("online", true, "ts", System.currentTimeMillis() - 123123, "type", "bs")
+            .get();
+        refresh();
+        ensureGreen(INDEX_NAME);
+        waitForSearchableDocs(4, primaryNode, replicaNode);
+
+        SearchResponse response = client().prepareSearch(INDEX_NAME)
+            .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
+            .setQuery(
+                boolQuery().must(termQuery("online", true))
+                    .must(
+                        boolQuery().should(
+                            boolQuery().must(rangeQuery("ts").lt(System.currentTimeMillis() - (15 * 1000))).must(termQuery("type", "bs"))
+                        )
+                            .should(
+                                boolQuery().must(rangeQuery("ts").lt(System.currentTimeMillis() - (15 * 1000))).must(termQuery("type", "s"))
+                            )
+                    )
+            )
+            .setVersion(true)
+            .setFrom(0)
+            .setSize(100)
+            .setExplain(true)
+            .get();
+        assertNoFailures(response);
+    }
+
+    public void testRestartPrimary_NoReplicas() throws Exception {
+        final String primary = internalCluster().startDataOnlyNode();
+        createIndex(INDEX_NAME);
+        ensureYellow(INDEX_NAME);
+
+        assertEquals(getNodeContainingPrimaryShard().getName(), primary);
+
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
+        if (randomBoolean()) {
+            flush(INDEX_NAME);
+        } else {
+            refresh(INDEX_NAME);
+        }
+
+        internalCluster().restartNode(primary);
+        ensureYellow(INDEX_NAME);
+        assertDocCounts(1, primary);
+    }
+
+    /**
+     * Tests whether segment replication supports realtime get requests and reads and parses source from the translog to serve strong reads.
+     */
+    public void testRealtimeGetRequestsSuccessful() {
+        final String primary = internalCluster().startDataOnlyNode();
+        // refresh interval disabled to ensure refresh rate of index (when data is ready for search) doesn't affect realtime get
+        assertAcked(
+            prepareCreate(INDEX_NAME).setSettings(Settings.builder().put("index.refresh_interval", -1).put(indexSettings()))
+                .addAlias(new Alias("alias"))
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+
+        GetResponse response = client(replica).prepareGet(indexOrAlias(), "1").get();
+        assertFalse(response.isExists());
+
+        // index doc 1
+        client().prepareIndex(indexOrAlias()).setId("1").setSource("foo", "bar").get();
+
+        // non realtime get 1
+        response = client().prepareGet(indexOrAlias(), "1").setRealtime(false).get();
+        assertFalse(response.isExists());
+
+        // realtime get 1
+        response = client(replica).prepareGet(indexOrAlias(), "1").get();
+        assertTrue(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+        assertThat(response.getSourceAsMap().get("foo").toString(), equalTo("bar"));
+
+        // index doc 2
+        client().prepareIndex(indexOrAlias()).setId("2").setSource("foo2", "bar2").setRouting(id).get();
+
+        // realtime get 2 (with routing)
+        response = client(replica).prepareGet(indexOrAlias(), "2").setRouting(id).get();
+        assertTrue(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+        assertThat(response.getSourceAsMap().get("foo2").toString(), equalTo("bar2"));
+    }
+
+    public void testRealtimeGetRequestsUnsuccessful() {
+        final String primary = internalCluster().startDataOnlyNode();
+        assertAcked(
+            prepareCreate(INDEX_NAME).setSettings(
+                Settings.builder().put("index.refresh_interval", -1).put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+            ).addAlias(new Alias("alias"))
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+        final String routingOtherShard = routingKeyForShard(INDEX_NAME, 1);
+
+        // index doc 1
+        client().prepareIndex(indexOrAlias()).setId("1").setSource("foo", "bar").setRouting(id).get();
+
+        // non realtime get 1
+        GetResponse response = client().prepareGet(indexOrAlias(), "1").setRealtime(false).get();
+        assertFalse(response.isExists());
+
+        // realtime get 1 (preference = _replica)
+        response = client(replica).prepareGet(indexOrAlias(), "1").setPreference(Preference.REPLICA.type()).get();
+        assertFalse(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+
+        // realtime get 1 (with routing set)
+        response = client(replica).prepareGet(INDEX_NAME, "1").setRouting(routingOtherShard).get();
+        assertFalse(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+    }
+
+    /**
+     * Tests whether segment replication supports realtime MultiGet requests and reads and parses source from the translog to serve strong reads.
+     */
+    public void testRealtimeMultiGetRequestsSuccessful() {
+        final String primary = internalCluster().startDataOnlyNode();
+        // refresh interval disabled to ensure refresh rate of index (when data is ready for search) doesn't affect realtime multi get
+        assertAcked(
+            prepareCreate(INDEX_NAME).setSettings(
+                Settings.builder().put("index.refresh_interval", -1).put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+            ).addAlias(new Alias("alias"))
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+
+        // index doc 1
+        client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").get();
+
+        // index doc 2
+        client().prepareIndex(INDEX_NAME).setId("2").setSource("foo2", "bar2").setRouting(id).get();
+
+        // multi get non realtime 1
+        MultiGetResponse mgetResponse = client().prepareMultiGet()
+            .add(new MultiGetRequest.Item(INDEX_NAME, "1"))
+            .add(new MultiGetRequest.Item("nonExistingIndex", "1"))
+            .setRealtime(false)
+            .get();
+        assertThat(mgetResponse.getResponses().length, is(2));
+
+        assertThat(mgetResponse.getResponses()[0].getIndex(), is(INDEX_NAME));
+        assertFalse(mgetResponse.getResponses()[0].isFailed());
+        assertFalse(mgetResponse.getResponses()[0].getResponse().isExists());
+
+        // multi get realtime 1
+        mgetResponse = client(replica).prepareMultiGet()
+            .add(new MultiGetRequest.Item(INDEX_NAME, "1"))
+            .add(new MultiGetRequest.Item(INDEX_NAME, "2").routing(id))
+            .add(new MultiGetRequest.Item("nonExistingIndex", "1"))
+            .get();
+
+        assertThat(mgetResponse.getResponses().length, is(3));
+        assertThat(mgetResponse.getResponses()[0].getIndex(), is(INDEX_NAME));
+        assertFalse(mgetResponse.getResponses()[0].isFailed());
+        assertThat(mgetResponse.getResponses()[0].getResponse().getSourceAsMap().get("foo").toString(), equalTo("bar"));
+
+        assertThat(mgetResponse.getResponses()[1].getIndex(), is(INDEX_NAME));
+        assertFalse(mgetResponse.getResponses()[1].isFailed());
+        assertThat(mgetResponse.getResponses()[1].getResponse().getSourceAsMap().get("foo2").toString(), equalTo("bar2"));
+
+        assertThat(mgetResponse.getResponses()[2].getIndex(), is("nonExistingIndex"));
+        assertTrue(mgetResponse.getResponses()[2].isFailed());
+        assertThat(mgetResponse.getResponses()[2].getFailure().getMessage(), is("no such index [nonExistingIndex]"));
+    }
+
+    public void testRealtimeMultiGetRequestsUnsuccessful() {
+        final String primary = internalCluster().startDataOnlyNode();
+        assertAcked(
+            prepareCreate(INDEX_NAME).setSettings(
+                Settings.builder().put("index.refresh_interval", -1).put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+            ).addAlias(new Alias("alias"))
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+        final String routingOtherShard = routingKeyForShard(INDEX_NAME, 1);
+
+        // index doc 1
+        client().prepareIndex(indexOrAlias()).setId("1").setSource("foo", "bar").setRouting(id).get();
+
+        // realtime multi get 1 (preference = _replica)
+        MultiGetResponse mgetResponse = client(replica).prepareMultiGet()
+            .add(new MultiGetRequest.Item(INDEX_NAME, "1"))
+            .setPreference(Preference.REPLICA.type())
+            .add(new MultiGetRequest.Item("nonExistingIndex", "1"))
+            .get();
+        assertThat(mgetResponse.getResponses().length, is(2));
+        assertThat(mgetResponse.getResponses()[0].getIndex(), is(INDEX_NAME));
+        assertFalse(mgetResponse.getResponses()[0].getResponse().isExists());
+
+        assertThat(mgetResponse.getResponses()[1].getIndex(), is("nonExistingIndex"));
+        assertTrue(mgetResponse.getResponses()[1].isFailed());
+
+        // realtime multi get 1 (routing set)
+        mgetResponse = client(replica).prepareMultiGet()
+            .add(new MultiGetRequest.Item(INDEX_NAME, "1").routing(routingOtherShard))
+            .add(new MultiGetRequest.Item("nonExistingIndex", "1"))
+            .get();
+        assertThat(mgetResponse.getResponses().length, is(2));
+        assertThat(mgetResponse.getResponses()[0].getIndex(), is(INDEX_NAME));
+        // expecting failure since we explicitly route request to a shard on which it doesn't exist
+        assertFalse(mgetResponse.getResponses()[0].getResponse().isExists());
+        assertThat(mgetResponse.getResponses()[1].getIndex(), is("nonExistingIndex"));
+        assertTrue(mgetResponse.getResponses()[1].isFailed());
+
+    }
+
+    /**
+     * Tests whether segment replication supports realtime termvector requests and reads and parses source from the translog to serve strong reads.
+     */
+    public void testRealtimeTermVectorRequestsSuccessful() throws IOException {
+        final String primary = internalCluster().startDataOnlyNode();
+        XContentBuilder mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .field("term_vector", "with_positions_offsets_payloads")
+            .field("analyzer", "tv_test")
+            .endObject()
+            .endObject()
+            .endObject();
+        // refresh interval disabled to ensure refresh rate of index (when data is ready for search) doesn't affect realtime termvectors
+        assertAcked(
+            prepareCreate(INDEX_NAME).setMapping(mapping)
+                .addAlias(new Alias("alias"))
+                .setSettings(
+                    Settings.builder()
+                        .put(indexSettings())
+                        .put("index.analysis.analyzer.tv_test.tokenizer", "standard")
+                        .put("index.refresh_interval", -1)
+                        .putList("index.analysis.analyzer.tv_test.filter", "lowercase")
+                )
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+
+        TermVectorsResponse response = client(replica).prepareTermVectors(indexOrAlias(), "1").get();
+        assertFalse(response.isExists());
+
+        // index doc 1
+        client().prepareIndex(INDEX_NAME)
+            .setId(Integer.toString(1))
+            .setSource(jsonBuilder().startObject().field("field", "the quick brown fox jumps over the lazy dog").endObject())
+            .execute()
+            .actionGet();
+
+        // non realtime termvectors 1
+        response = client().prepareTermVectors(indexOrAlias(), Integer.toString(1)).setRealtime(false).get();
+        assertFalse(response.isExists());
+
+        // realtime termvectors 1
+        TermVectorsRequestBuilder resp = client().prepareTermVectors(indexOrAlias(), Integer.toString(1))
+            .setPayloads(true)
+            .setOffsets(true)
+            .setPositions(true)
+            .setRealtime(true)
+            .setSelectedFields();
+        response = resp.execute().actionGet();
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+        assertThat("doc id: " + 1 + " doesn't exists but should", response.isExists(), equalTo(true));
+        Fields fields = response.getFields();
+        assertThat(fields.size(), equalTo(1));
+
+        // index doc 2 with routing
+        client().prepareIndex(INDEX_NAME)
+            .setId(Integer.toString(2))
+            .setRouting(id)
+            .setSource(jsonBuilder().startObject().field("field", "the quick brown fox jumps over the lazy dog").endObject())
+            .execute()
+            .actionGet();
+
+        // realtime termvectors 2 with routing
+        resp = client().prepareTermVectors(indexOrAlias(), Integer.toString(2))
+            .setPayloads(true)
+            .setOffsets(true)
+            .setPositions(true)
+            .setRouting(id)
+            .setSelectedFields();
+        response = resp.execute().actionGet();
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+        assertThat("doc id: " + 1 + " doesn't exists but should", response.isExists(), equalTo(true));
+        fields = response.getFields();
+        assertThat(fields.size(), equalTo(1));
+
+    }
+
+    public void testRealtimeTermVectorRequestsUnSuccessful() throws IOException {
+        final String primary = internalCluster().startDataOnlyNode();
+        XContentBuilder mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .field("term_vector", "with_positions_offsets_payloads")
+            .field("analyzer", "tv_test")
+            .endObject()
+            .endObject()
+            .endObject();
+        // refresh interval disabled to ensure refresh rate of index (when data is ready for search) doesn't affect realtime termvectors
+        assertAcked(
+            prepareCreate(INDEX_NAME).setMapping(mapping)
+                .addAlias(new Alias("alias"))
+                .setSettings(
+                    Settings.builder()
+                        .put(indexSettings())
+                        .put("index.analysis.analyzer.tv_test.tokenizer", "standard")
+                        .put("index.refresh_interval", -1)
+                        .putList("index.analysis.analyzer.tv_test.filter", "lowercase")
+                        .put(indexSettings())
+                        .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+                )
+        );
+        final String replica = internalCluster().startDataOnlyNode();
+        ensureGreen(INDEX_NAME);
+        final String id = routingKeyForShard(INDEX_NAME, 0);
+        final String routingOtherShard = routingKeyForShard(INDEX_NAME, 1);
+
+        // index doc 1
+        client().prepareIndex(INDEX_NAME)
+            .setId(Integer.toString(1))
+            .setSource(jsonBuilder().startObject().field("field", "the quick brown fox jumps over the lazy dog").endObject())
+            .setRouting(id)
+            .execute()
+            .actionGet();
+
+        // non realtime termvectors 1
+        TermVectorsResponse response = client().prepareTermVectors(indexOrAlias(), Integer.toString(1)).setRealtime(false).get();
+        assertFalse(response.isExists());
+
+        // realtime termvectors (preference = _replica)
+        TermVectorsRequestBuilder resp = client(replica).prepareTermVectors(indexOrAlias(), Integer.toString(1))
+            .setPayloads(true)
+            .setOffsets(true)
+            .setPositions(true)
+            .setPreference(Preference.REPLICA.type())
+            .setRealtime(true)
+            .setSelectedFields();
+        response = resp.execute().actionGet();
+
+        assertFalse(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+
+        // realtime termvectors (with routing set)
+        resp = client(replica).prepareTermVectors(indexOrAlias(), Integer.toString(1))
+            .setPayloads(true)
+            .setOffsets(true)
+            .setPositions(true)
+            .setRouting(routingOtherShard)
+            .setSelectedFields();
+        response = resp.execute().actionGet();
+
+        assertFalse(response.isExists());
+        assertThat(response.getIndex(), equalTo(INDEX_NAME));
+
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java
new file mode 100644
index 0000000000000..97e2045285d2f
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java
@@ -0,0 +1,580 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.OpenSearchCorruptionException;
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.reroute.ClusterRerouteResponse;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.WriteRequest;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
+import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+/**
+ * This test class verifies primary shard relocation with segment replication as replication strategy.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationRelocationIT extends SegmentReplicationBaseIT {
+    private final TimeValue ACCEPTABLE_RELOCATION_TIME = new TimeValue(5, TimeUnit.MINUTES);
+
+    private void createIndex(int replicaCount) {
+        prepareCreate(INDEX_NAME, Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, replicaCount)).get();
+    }
+
+    /**
+     * This test verifies happy path when primary shard is relocated newly added node (target) in the cluster. Before
+     * relocation and after relocation documents are indexed and documents are verified
+     */
+    public void testPrimaryRelocation() throws Exception {
+        final String oldPrimary = internalCluster().startNode();
+        createIndex(1);
+        final String replica = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+        final int initialDocCount = scaledRandomIntBetween(10, 100);
+        final WriteRequest.RefreshPolicy refreshPolicy = randomFrom(WriteRequest.RefreshPolicy.values());
+        final List<ActionFuture<IndexResponse>> pendingIndexResponses = new ArrayList<>();
+        for (int i = 0; i < initialDocCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+
+        logger.info("--> start another node");
+        final String newPrimary = internalCluster().startNode(featureFlagSettings());
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        logger.info("--> relocate the shard");
+        client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new MoveAllocationCommand(INDEX_NAME, 0, oldPrimary, newPrimary))
+            .execute()
+            .actionGet();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNoRelocatingShards(true)
+            .setTimeout(ACCEPTABLE_RELOCATION_TIME)
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        logger.info("--> get the state, verify shard 1 primary moved from node1 to node2");
+        ClusterState state = client().admin().cluster().prepareState().execute().actionGet().getState();
+        assertEquals(
+            state.getRoutingNodes().node(state.nodes().resolveNode(newPrimary).getId()).iterator().next().state(),
+            ShardRoutingState.STARTED
+        );
+
+        for (int i = initialDocCount; i < 2 * initialDocCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+        assertBusy(() -> {
+            client().admin().indices().prepareRefresh().execute().actionGet();
+            assertTrue(pendingIndexResponses.stream().allMatch(ActionFuture::isDone));
+        }, 1, TimeUnit.MINUTES);
+        flushAndRefresh(INDEX_NAME);
+        logger.info("--> verify count again {}", 2 * initialDocCount);
+        waitForSearchableDocs(2 * initialDocCount, newPrimary, replica);
+        verifyStoreContent();
+    }
+
+    /**
+     * This test verifies the primary relocation behavior when segment replication round fails during recovery. Post
+     * failure, more documents are ingested and verified on replica; which confirms older primary still refreshing the
+     * replicas.
+     */
+    public void testPrimaryRelocationWithSegRepFailure() throws Exception {
+        final String oldPrimary = internalCluster().startNode();
+        createIndex(1);
+        final String replica = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+        final int initialDocCount = scaledRandomIntBetween(10, 100);
+        final WriteRequest.RefreshPolicy refreshPolicy = randomFrom(WriteRequest.RefreshPolicy.values());
+        final List<ActionFuture<IndexResponse>> pendingIndexResponses = new ArrayList<>();
+        for (int i = 0; i < initialDocCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+
+        logger.info("--> start another node");
+        final String newPrimary = internalCluster().startNode(featureFlagSettings());
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        // Mock transport service to add behaviour of throwing corruption exception during segment replication process.
+        MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            oldPrimary
+        ));
+        mockTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, newPrimary),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationTargetService.Actions.FILE_CHUNK)) {
+                    throw new OpenSearchCorruptionException("expected");
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+
+        logger.info("--> relocate the shard");
+        client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new MoveAllocationCommand(INDEX_NAME, 0, oldPrimary, newPrimary))
+            .execute()
+            .actionGet();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNoRelocatingShards(true)
+            .setTimeout(ACCEPTABLE_RELOCATION_TIME)
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        for (int i = initialDocCount; i < 2 * initialDocCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+
+        logger.info("Verify older primary is still refreshing replica nodes");
+        assertBusy(() -> {
+            client().admin().indices().prepareRefresh().execute().actionGet();
+            assertTrue(pendingIndexResponses.stream().allMatch(ActionFuture::isDone));
+        }, 1, TimeUnit.MINUTES);
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(2 * initialDocCount, oldPrimary, replica);
+        verifyStoreContent();
+    }
+
+    /**
+     * This test verifies primary recovery behavior with continuous ingestion
+     *
+     */
+    public void testRelocateWhileContinuouslyIndexingAndWaitingForRefresh() throws Exception {
+        final String primary = internalCluster().startNode();
+        createIndex(1);
+        final String replica = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+        final int totalDocCount = 1000;
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        logger.info("--> flush to have segments on disk");
+        client().admin().indices().prepareFlush().execute().actionGet();
+
+        logger.info("--> index more docs so there are ops in the transaction log");
+        final List<ActionFuture<IndexResponse>> pendingIndexResponses = new ArrayList<>();
+        for (int i = 10; i < 20; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+
+        final String newPrimary = internalCluster().startNode();
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        logger.info("--> relocate the shard from primary to replica");
+        ActionFuture<ClusterRerouteResponse> relocationListener = client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new MoveAllocationCommand(INDEX_NAME, 0, primary, newPrimary))
+            .execute();
+        for (int i = 20; i < totalDocCount; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+        relocationListener.actionGet();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNoRelocatingShards(true)
+            .setTimeout(ACCEPTABLE_RELOCATION_TIME)
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        logger.info("--> verifying count");
+        assertBusy(() -> {
+            client().admin().indices().prepareRefresh().execute().actionGet();
+            assertTrue(pendingIndexResponses.stream().allMatch(ActionFuture::isDone));
+        }, 1, TimeUnit.MINUTES);
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(totalDocCount, newPrimary, replica);
+        verifyStoreContent();
+    }
+
+    /**
+     * This test verifies delayed operations during primary handoff are replayed and searchable. It does so by halting
+     * segment replication which is performed while holding primary indexing permits which results in queuing of
+     * operations during handoff. The test verifies all docs ingested are searchable on new primary.
+     *
+     */
+    public void testRelocateWithQueuedOperationsDuringHandoff() throws Exception {
+        final String primary = internalCluster().startNode();
+        createIndex(1);
+        final String replica = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+        final int totalDocCount = 2000;
+
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        logger.info("--> flush to have segments on disk");
+        client().admin().indices().prepareFlush().execute().actionGet();
+        final WriteRequest.RefreshPolicy refreshPolicy = randomFrom(WriteRequest.RefreshPolicy.values());
+
+        logger.info("--> index more docs so there are ops in the transaction log");
+        final List<ActionFuture<IndexResponse>> pendingIndexResponses = new ArrayList<>();
+        for (int i = 10; i < 20; i++) {
+            pendingIndexResponses.add(
+                client().prepareIndex(INDEX_NAME)
+                    .setId(Integer.toString(i))
+                    .setRefreshPolicy(refreshPolicy)
+                    .setSource("field", "value" + i)
+                    .execute()
+            );
+        }
+        final String newPrimary = internalCluster().startNode();
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+        ensureGreen(INDEX_NAME);
+
+        // Get mock transport service from newPrimary, halt recovery during segment replication (during handoff) to allow indexing in
+        // parallel.
+        MockTransportService mockTargetTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            newPrimary
+        ));
+        CountDownLatch blockSegRepLatch = new CountDownLatch(1);
+        CountDownLatch waitForIndexingLatch = new CountDownLatch(1);
+        mockTargetTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, primary),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES)) {
+                    blockSegRepLatch.countDown();
+                    try {
+                        waitForIndexingLatch.await();
+                    } catch (InterruptedException e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+        Thread indexingThread = new Thread(() -> {
+            // Wait for relocation to halt at SegRep. Ingest docs at that point.
+            try {
+                blockSegRepLatch.await();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+            for (int i = 20; i < totalDocCount; i++) {
+                pendingIndexResponses.add(
+                    client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute()
+                );
+            }
+            waitForIndexingLatch.countDown();
+        });
+
+        logger.info("--> relocate the shard from primary to newPrimary");
+        ActionFuture<ClusterRerouteResponse> relocationListener = client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new MoveAllocationCommand(INDEX_NAME, 0, primary, newPrimary))
+            .execute();
+
+        // This thread first waits for recovery to halt during segment replication. After which it ingests data to ensure
+        // documents are queued.
+        indexingThread.start();
+        indexingThread.join();
+        relocationListener.actionGet();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNoRelocatingShards(true)
+            .setTimeout(ACCEPTABLE_RELOCATION_TIME)
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        logger.info("--> verifying count");
+        assertBusy(() -> {
+            client().admin().indices().prepareRefresh().execute().actionGet();
+            assertTrue(pendingIndexResponses.stream().allMatch(ActionFuture::isDone));
+        }, 2, TimeUnit.MINUTES);
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(totalDocCount, replica, newPrimary);
+        verifyStoreContent();
+    }
+
+    /**
+     * This test verifies that adding a new node which results in peer recovery as replica; also bring replica's
+     * replication checkpoint upto the primary's by performing a round of segment replication.
+     */
+    public void testNewlyAddedReplicaIsUpdated() throws Exception {
+        final String primary = internalCluster().startNode();
+        prepareCreate(INDEX_NAME, Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0))
+            .get();
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        logger.info("--> flush so we have some segment files on disk");
+        flush(INDEX_NAME);
+        logger.info("--> index more docs so we have something in the translog");
+        for (int i = 10; i < 20; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        refresh(INDEX_NAME);
+        assertEquals(client().prepareSearch(INDEX_NAME).setSize(0).execute().actionGet().getHits().getTotalHits().value, 20L);
+
+        logger.info("--> start empty node to add replica shard");
+        final String replica = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+        // Update replica count settings to 1 so that peer recovery triggers and recover replica
+        assertAcked(
+            client().admin().indices().prepareUpdateSettings(INDEX_NAME).setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 1))
+        );
+        ensureGreen(INDEX_NAME);
+        flushAndRefresh(INDEX_NAME);
+        waitForSearchableDocs(20, primary, replica);
+        verifyStoreContent();
+    }
+
+    /**
+     * This test verifies that replica shard is not added to the cluster when doing a round of segment replication fails during peer recovery.
+     */
+    public void testAddNewReplicaFailure() throws Exception {
+        logger.info("--> starting [Primary Node] ...");
+        final String primaryNode = internalCluster().startNode();
+
+        logger.info("--> creating test index ...");
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0)
+
+        ).get();
+
+        logger.info("--> index 10 docs");
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        logger.info("--> flush so we have some segment files on disk");
+        flush(INDEX_NAME);
+        logger.info("--> index more docs so we have something in the translog");
+        for (int i = 10; i < 20; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        refresh(INDEX_NAME);
+        logger.info("--> verifying count");
+        assertEquals(client().prepareSearch(INDEX_NAME).setSize(0).execute().actionGet().getHits().getTotalHits().value, 20L);
+
+        logger.info("--> start empty node to add replica shard");
+        final String replica = internalCluster().startNode();
+
+        final CountDownLatch waitForRecovery = new CountDownLatch(1);
+        // Mock transport service to add behaviour of throwing corruption exception during segment replication process.
+        MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            primaryNode
+        ));
+        mockTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, replica),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationTargetService.Actions.FILE_CHUNK)) {
+                    waitForRecovery.countDown();
+                    throw new OpenSearchCorruptionException("expected");
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+        ensureGreen(INDEX_NAME);
+        // Add Replica shard to the new empty replica node
+        assertAcked(
+            client().admin().indices().prepareUpdateSettings(INDEX_NAME).setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 1))
+        );
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, replica);
+        waitForRecovery.await();
+        assertBusy(() -> assertTrue(indicesService.hasIndex(resolveIndex(INDEX_NAME))));
+
+        // Verify that cluster state is not green and replica shard failed during a round of segment replication is not added to the cluster
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("2")
+            .setWaitForGreenStatus()
+            .setTimeout(TimeValue.timeValueSeconds(2))
+            .execute()
+            .actionGet();
+        assertTrue(clusterHealthResponse.isTimedOut());
+        ensureYellow(INDEX_NAME);
+    }
+
+    public void testFlushAfterRelocation() throws Exception {
+        // Starting two nodes with primary and replica shards respectively.
+        final String primaryNode = internalCluster().startNode();
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder()
+                // we want to control refreshes
+                .put("index.refresh_interval", -1)
+        ).get();
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+
+        // Start another empty node for relocation
+        final String newPrimary = internalCluster().startNode();
+        ClusterHealthResponse clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNodes("3")
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+        ensureGreen(INDEX_NAME);
+
+        // Start indexing docs
+        final int initialDocCount = scaledRandomIntBetween(2000, 3000);
+        for (int i = 0; i < initialDocCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+
+        final IndexShard replicaShard = getIndexShard(replicaNode, INDEX_NAME);
+
+        // Verify segment replication event never happened on replica shard other than recovery.
+        assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setPreference("_only_local").setSize(0).get(), 0);
+        assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setPreference("_only_local").setSize(0).get(), 0);
+
+        SegmentReplicationStatsResponse segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats(INDEX_NAME)
+            .execute()
+            .actionGet();
+        final Set<SegmentReplicationShardStats> replicaStats = segmentReplicationStatsResponse.getReplicationStats()
+            .get(INDEX_NAME)
+            .get(0)
+            .getReplicaStats();
+        assertEquals(
+            Set.of(replicaShard.routingEntry().allocationId().getId()),
+            replicaStats.stream().map(SegmentReplicationShardStats::getAllocationId).collect(Collectors.toSet())
+        );
+        // the primary still has not refreshed to update its checkpoint, so our replica is not yet behind.
+        assertEquals(0, replicaStats.stream().findFirst().get().getCheckpointsBehindCount());
+
+        // Relocate primary to new primary. When new primary starts it does perform a flush.
+        logger.info("--> relocate the shard from primary to newPrimary");
+        ActionFuture<ClusterRerouteResponse> relocationListener = client().admin()
+            .cluster()
+            .prepareReroute()
+            .add(new MoveAllocationCommand(INDEX_NAME, 0, primaryNode, newPrimary))
+            .execute();
+        clusterHealthResponse = client().admin()
+            .cluster()
+            .prepareHealth()
+            .setWaitForEvents(Priority.LANGUID)
+            .setWaitForNoRelocatingShards(true)
+            .setTimeout(ACCEPTABLE_RELOCATION_TIME)
+            .execute()
+            .actionGet();
+        assertEquals(clusterHealthResponse.isTimedOut(), false);
+
+        // Verify if all docs are present in replica after relocation, if new relocated primary doesn't flush after relocation the below
+        // assert will fail.
+        assertBusy(() -> {
+            assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setPreference("_only_local").setSize(0).get(), initialDocCount);
+        });
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationResizeRequestIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationResizeRequestIT.java
new file mode 100644
index 0000000000000..fb06a97bd51c2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationResizeRequestIT.java
@@ -0,0 +1,248 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.admin.indices.shrink.ResizeType;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.Preference;
+import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.query.TermsQueryBuilder;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+/**
+ * This test class verifies Resize Reequests (Shrink, Split, Clone) with segment replication as replication strategy.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 2)
+public class SegmentReplicationResizeRequestIT extends SegmentReplicationBaseIT {
+
+    public void testCreateShrinkIndexThrowsExceptionWhenReplicasBehind() throws Exception {
+
+        // create index with -1 as refresh interval as we are blocking segrep and we want to control refreshes.
+        prepareCreate("test").setSettings(
+            Settings.builder()
+                .put(indexSettings())
+                .put("index.refresh_interval", -1)
+                .put("index.number_of_replicas", 1)
+                .put("number_of_shards", 2)
+        ).get();
+
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
+        assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
+        // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
+        // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
+        // to the require._name below.
+        ensureGreen();
+
+        // block Segment Replication so that replicas never get the docs from primary
+        CountDownLatch latch = new CountDownLatch(1);
+        try (final Releasable ignored = blockReplication(List.of(discoveryNodes[0].getName()), latch)) {
+            final int docs = 500;
+            for (int i = 0; i < docs; i++) {
+                client().prepareIndex("test").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
+            }
+
+            // block writes on index before performing shrink operation
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(
+                    Settings.builder()
+                        .put("index.routing.allocation.require._name", discoveryNodes[0].getName())
+                        .put("index.blocks.write", true)
+                )
+                .get();
+            ensureGreen();
+
+            // Trigger Shrink operation, as replicas don't have any docs it will throw exception that replicas haven't caught up
+            IllegalStateException exception = assertThrows(
+                IllegalStateException.class,
+                () -> client().admin()
+                    .indices()
+                    .prepareResizeIndex("test", "target")
+                    .setResizeType(ResizeType.SHRINK)
+                    .setSettings(
+                        Settings.builder()
+                            .put("index.number_of_replicas", 1)
+                            .putNull("index.blocks.write")
+                            .putNull("index.routing.allocation.require._name")
+                            .build()
+                    )
+                    .get()
+            );
+            assertEquals(
+                " For index [test] replica shards haven't caught up with primary, please retry after sometime.",
+                exception.getMessage()
+            );
+
+        }
+
+    }
+
+    public void testCreateSplitIndexWithSegmentReplicationBlocked() throws Exception {
+        internalCluster().ensureAtLeastNumDataNodes(3);
+
+        // create index with -1 as refresh interval as we are blocking segrep and we want to control refreshes.
+        prepareCreate("test").setSettings(
+            Settings.builder()
+                .put(indexSettings())
+                .put("index.refresh_interval", -1)
+                .put("index.number_of_replicas", 1)
+                .put("number_of_shards", 3)
+        ).get();
+
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
+        assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
+        // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
+        // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
+        // to the require._name below.
+        ensureGreen();
+
+        CountDownLatch latch = new CountDownLatch(1);
+
+        // block Segment Replication so that replicas never get the docs from primary
+        try (final Releasable ignored = blockReplication(List.of(discoveryNodes[0].getName()), latch)) {
+            final int docs = 500;
+            for (int i = 0; i < docs; i++) {
+                client().prepareIndex("test").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
+            }
+            refresh();
+            assertBusy(() -> {
+                assertHitCount(
+                    client().prepareSearch("test")
+                        .setQuery(new TermsQueryBuilder("foo", "bar"))
+                        .setPreference(Preference.PRIMARY.type())
+                        .get(),
+                    docs
+                );
+            });
+
+            // block writes on index before performing split operation
+            client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder().put("index.blocks.write", true)).get();
+            ensureGreen();
+
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(
+                    Settings.builder().put(EnableAllocationDecider.CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), "none")
+                )
+                .get();
+
+            // Trigger split operation
+            assertAcked(
+                client().admin()
+                    .indices()
+                    .prepareResizeIndex("test", "target")
+                    .setResizeType(ResizeType.SPLIT)
+                    .setSettings(
+                        Settings.builder()
+                            .put("index.number_of_replicas", 1)
+                            .put("index.number_of_shards", 6)
+                            .putNull("index.blocks.write")
+                            .build()
+                    )
+                    .get()
+            );
+            ensureGreen();
+
+            // verify that all docs are present in new target index
+            assertHitCount(
+                client().prepareSearch("target")
+                    .setQuery(new TermsQueryBuilder("foo", "bar"))
+                    .setPreference(Preference.PRIMARY.type())
+                    .get(),
+                docs
+            );
+        }
+
+    }
+
+    public void testCloneIndex() throws Exception {
+        internalCluster().ensureAtLeastNumDataNodes(3);
+
+        // create index with -1 as refresh interval as we are blocking segrep and we want to control refreshes.
+        prepareCreate("test").setSettings(
+            Settings.builder().put(indexSettings()).put("index.number_of_replicas", 1).put("number_of_shards", randomIntBetween(1, 5))
+        ).get();
+
+        final Map<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes().getDataNodes();
+        assertTrue("at least 2 nodes but was: " + dataNodes.size(), dataNodes.size() >= 2);
+        DiscoveryNode[] discoveryNodes = dataNodes.values().toArray(new DiscoveryNode[0]);
+        // ensure all shards are allocated otherwise the ensure green below might not succeed since we require the merge node
+        // if we change the setting too quickly we will end up with one replica unassigned which can't be assigned anymore due
+        // to the require._name below.
+        ensureGreen();
+
+        CountDownLatch latch = new CountDownLatch(1);
+
+        // block Segment Replication so that replicas never get the docs from primary
+        try (final Releasable ignored = blockReplication(List.of(discoveryNodes[0].getName()), latch)) {
+            final int docs = 500;
+            for (int i = 0; i < docs; i++) {
+                client().prepareIndex("test").setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", MediaTypeRegistry.JSON).get();
+            }
+            refresh();
+            assertBusy(() -> {
+                assertHitCount(
+                    client().prepareSearch("test")
+                        .setQuery(new TermsQueryBuilder("foo", "bar"))
+                        .setPreference(Preference.PRIMARY.type())
+                        .get(),
+                    docs
+                );
+            });
+
+            // block writes on index before performing clone operation
+            client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder().put("index.blocks.write", true)).get();
+            ensureGreen();
+
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(
+                    Settings.builder().put(EnableAllocationDecider.CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), "none")
+                )
+                .get();
+
+            // Trigger split operation
+            assertAcked(
+                client().admin()
+                    .indices()
+                    .prepareResizeIndex("test", "target")
+                    .setResizeType(ResizeType.CLONE)
+                    .setSettings(Settings.builder().put("index.number_of_replicas", 1).putNull("index.blocks.write").build())
+                    .get()
+            );
+            ensureGreen();
+
+            // verify that all docs are present in new target index
+            assertHitCount(
+                client().prepareSearch("target")
+                    .setQuery(new TermsQueryBuilder("foo", "bar"))
+                    .setPreference(Preference.PRIMARY.type())
+                    .get(),
+                docs
+            );
+        }
+
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationStatsIT.java
new file mode 100644
index 0000000000000..766471fdc0756
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationStatsIT.java
@@ -0,0 +1,433 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.admin.cluster.node.stats.NodeStats;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
+import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.ReplicationStats;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.transport.TransportService;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationStatsIT extends SegmentReplicationBaseIT {
+
+    public void testSegmentReplicationStatsResponse() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        String dataNode = internalCluster().startDataOnlyNode();
+        String anotherDataNode = internalCluster().startDataOnlyNode();
+
+        int numShards = 4;
+        assertAcked(
+            prepareCreate(
+                INDEX_NAME,
+                0,
+                Settings.builder()
+                    .put("number_of_shards", numShards)
+                    .put("number_of_replicas", 1)
+                    .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            )
+        );
+        ensureGreen();
+        final long numDocs = scaledRandomIntBetween(50, 100);
+        for (int i = 0; i < numDocs; i++) {
+            index(INDEX_NAME, "doc", Integer.toString(i));
+        }
+        refresh(INDEX_NAME);
+        ensureSearchable(INDEX_NAME);
+
+        assertBusy(() -> {
+            SegmentReplicationStatsResponse segmentReplicationStatsResponse = dataNodeClient().admin()
+                .indices()
+                .prepareSegmentReplicationStats(INDEX_NAME)
+                .setDetailed(true)
+                .execute()
+                .actionGet();
+            SegmentReplicationPerGroupStats perGroupStats = segmentReplicationStatsResponse.getReplicationStats().get(INDEX_NAME).get(0);
+            final SegmentReplicationState currentReplicationState = perGroupStats.getReplicaStats()
+                .stream()
+                .findFirst()
+                .get()
+                .getCurrentReplicationState();
+            assertEquals(segmentReplicationStatsResponse.getReplicationStats().size(), 1);
+            assertEquals(segmentReplicationStatsResponse.getTotalShards(), numShards * 2);
+            assertEquals(segmentReplicationStatsResponse.getSuccessfulShards(), numShards * 2);
+            assertNotNull(currentReplicationState);
+            assertEquals(currentReplicationState.getStage(), SegmentReplicationState.Stage.DONE);
+            assertTrue(currentReplicationState.getIndex().recoveredFileCount() > 0);
+        }, 1, TimeUnit.MINUTES);
+    }
+
+    public void testSegmentReplicationStatsResponseForActiveOnly() throws Exception {
+        final String primaryNode = internalCluster().startNode();
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode();
+        ensureGreen(INDEX_NAME);
+
+        // index 10 docs
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        refresh(INDEX_NAME);
+
+        // index 10 more docs
+        waitForSearchableDocs(10L, asList(primaryNode, replicaNode));
+        for (int i = 10; i < 20; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        final CountDownLatch waitForReplication = new CountDownLatch(1);
+
+        final CountDownLatch waitForAssertions = new CountDownLatch(1);
+        // Mock transport service to add behaviour of waiting in GET_SEGMENT_FILES Stage of a segment replication event.
+        MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
+            TransportService.class,
+            replicaNode
+        ));
+        mockTransportService.addSendBehavior(
+            internalCluster().getInstance(TransportService.class, primaryNode),
+            (connection, requestId, action, request, options) -> {
+                if (action.equals(SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES)) {
+                    waitForReplication.countDown();
+                    try {
+                        waitForAssertions.await();
+                    } catch (InterruptedException e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+                connection.sendRequest(requestId, action, request, options);
+            }
+        );
+        refresh(INDEX_NAME);
+        try {
+            waitForReplication.await();
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+
+        // verifying active_only by checking if current stage is GET_FILES STAGE
+        SegmentReplicationStatsResponse activeOnlyResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats(INDEX_NAME)
+            .setActiveOnly(true)
+            .setDetailed(true)
+            .execute()
+            .actionGet();
+        SegmentReplicationPerGroupStats perGroupStats = activeOnlyResponse.getReplicationStats().get(INDEX_NAME).get(0);
+        SegmentReplicationState.Stage stage = perGroupStats.getReplicaStats()
+            .stream()
+            .findFirst()
+            .get()
+            .getCurrentReplicationState()
+            .getStage();
+        assertEquals(SegmentReplicationState.Stage.GET_FILES, stage);
+        waitForAssertions.countDown();
+    }
+
+    public void testNonDetailedResponse() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        int numReplicas = 4;
+        List<String> nodes = new ArrayList<>();
+        final String primaryNode = internalCluster().startNode();
+        nodes.add(primaryNode);
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numReplicas)
+                .build()
+        );
+        ensureYellow(INDEX_NAME);
+        for (int i = 0; i < numReplicas; i++) {
+            nodes.add(internalCluster().startNode());
+        }
+        ensureGreen(INDEX_NAME);
+
+        final long numDocs = scaledRandomIntBetween(50, 100);
+        for (int i = 0; i < numDocs; i++) {
+            index(INDEX_NAME, "doc", Integer.toString(i));
+        }
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(numDocs, nodes);
+
+        final IndexShard indexShard = getIndexShard(primaryNode, INDEX_NAME);
+
+        assertBusy(() -> {
+            SegmentReplicationStatsResponse segmentReplicationStatsResponse = dataNodeClient().admin()
+                .indices()
+                .prepareSegmentReplicationStats(INDEX_NAME)
+                .execute()
+                .actionGet();
+
+            final Map<String, List<SegmentReplicationPerGroupStats>> replicationStats = segmentReplicationStatsResponse
+                .getReplicationStats();
+            assertEquals(1, replicationStats.size());
+            final List<SegmentReplicationPerGroupStats> replicationPerGroupStats = replicationStats.get(INDEX_NAME);
+            assertEquals(1, replicationPerGroupStats.size());
+            final SegmentReplicationPerGroupStats perGroupStats = replicationPerGroupStats.get(0);
+            assertEquals(perGroupStats.getShardId(), indexShard.shardId());
+            final Set<SegmentReplicationShardStats> replicaStats = perGroupStats.getReplicaStats();
+            assertEquals(4, replicaStats.size());
+            for (SegmentReplicationShardStats replica : replicaStats) {
+                assertNotNull(replica.getCurrentReplicationState());
+            }
+        });
+    }
+
+    public void testGetSpecificShard() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        List<String> nodes = new ArrayList<>();
+        final String primaryNode = internalCluster().startNode();
+        nodes.add(primaryNode);
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                .build()
+        );
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        nodes.add(internalCluster().startNode());
+        ensureGreen(INDEX_NAME);
+
+        final long numDocs = scaledRandomIntBetween(50, 100);
+        for (int i = 0; i < numDocs; i++) {
+            index(INDEX_NAME, "doc", Integer.toString(i));
+        }
+        refresh(INDEX_NAME);
+        waitForSearchableDocs(numDocs, nodes);
+
+        final IndexShard indexShard = getIndexShard(primaryNode, INDEX_NAME);
+
+        // search for all
+        SegmentReplicationStatsResponse segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats(INDEX_NAME)
+            .setActiveOnly(true)
+            .execute()
+            .actionGet();
+
+        Map<String, List<SegmentReplicationPerGroupStats>> replicationStats = segmentReplicationStatsResponse.getReplicationStats();
+        assertEquals(1, replicationStats.size());
+        List<SegmentReplicationPerGroupStats> replicationPerGroupStats = replicationStats.get(INDEX_NAME);
+        assertEquals(2, replicationPerGroupStats.size());
+        for (SegmentReplicationPerGroupStats group : replicationPerGroupStats) {
+            assertEquals(1, group.getReplicaStats().size());
+        }
+
+        // now search for one shard.
+        final int id = indexShard.shardId().getId();
+        segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats(INDEX_NAME)
+            .setActiveOnly(true)
+            .shards(String.valueOf(id))
+            .execute()
+            .actionGet();
+
+        replicationStats = segmentReplicationStatsResponse.getReplicationStats();
+        assertEquals(1, replicationStats.size());
+        replicationPerGroupStats = replicationStats.get(INDEX_NAME);
+        assertEquals(1, replicationPerGroupStats.size());
+        for (SegmentReplicationPerGroupStats group : replicationPerGroupStats) {
+            assertEquals(group.getShardId(), indexShard.shardId());
+            assertEquals(1, group.getReplicaStats().size());
+        }
+
+    }
+
+    public void testMultipleIndices() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final String index_2 = "tst-index-2";
+        List<String> nodes = new ArrayList<>();
+        final String primaryNode = internalCluster().startNode();
+        nodes.add(primaryNode);
+        createIndex(INDEX_NAME, index_2);
+
+        ensureYellowAndNoInitializingShards(INDEX_NAME, index_2);
+        nodes.add(internalCluster().startNode());
+        ensureGreen(INDEX_NAME, index_2);
+
+        final long numDocs = scaledRandomIntBetween(50, 100);
+        for (int i = 0; i < numDocs; i++) {
+            index(INDEX_NAME, "doc", Integer.toString(i));
+            index(index_2, "doc", Integer.toString(i));
+        }
+        refresh(INDEX_NAME, index_2);
+        waitForSearchableDocs(INDEX_NAME, numDocs, nodes);
+        waitForSearchableDocs(index_2, numDocs, nodes);
+
+        final IndexShard index_1_primary = getIndexShard(primaryNode, INDEX_NAME);
+        final IndexShard index_2_primary = getIndexShard(primaryNode, index_2);
+
+        assertTrue(index_1_primary.routingEntry().primary());
+        assertTrue(index_2_primary.routingEntry().primary());
+
+        // test both indices are returned in the response.
+        SegmentReplicationStatsResponse segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats()
+            .execute()
+            .actionGet();
+
+        Map<String, List<SegmentReplicationPerGroupStats>> replicationStats = segmentReplicationStatsResponse.getReplicationStats();
+        assertEquals(2, replicationStats.size());
+        List<SegmentReplicationPerGroupStats> replicationPerGroupStats = replicationStats.get(INDEX_NAME);
+        assertEquals(1, replicationPerGroupStats.size());
+        SegmentReplicationPerGroupStats perGroupStats = replicationPerGroupStats.get(0);
+        assertEquals(perGroupStats.getShardId(), index_1_primary.shardId());
+        Set<SegmentReplicationShardStats> replicaStats = perGroupStats.getReplicaStats();
+        assertEquals(1, replicaStats.size());
+        for (SegmentReplicationShardStats replica : replicaStats) {
+            assertNotNull(replica.getCurrentReplicationState());
+        }
+
+        replicationPerGroupStats = replicationStats.get(index_2);
+        assertEquals(1, replicationPerGroupStats.size());
+        perGroupStats = replicationPerGroupStats.get(0);
+        assertEquals(perGroupStats.getShardId(), index_2_primary.shardId());
+        replicaStats = perGroupStats.getReplicaStats();
+        assertEquals(1, replicaStats.size());
+        for (SegmentReplicationShardStats replica : replicaStats) {
+            assertNotNull(replica.getCurrentReplicationState());
+        }
+
+        // test only single index queried.
+        segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats()
+            .setIndices(index_2)
+            .execute()
+            .actionGet();
+        assertEquals(1, segmentReplicationStatsResponse.getReplicationStats().size());
+        assertTrue(segmentReplicationStatsResponse.getReplicationStats().containsKey(index_2));
+    }
+
+    public void testQueryAgainstDocRepIndex() {
+        internalCluster().startClusterManagerOnlyNode();
+        List<String> nodes = new ArrayList<>();
+        final String primaryNode = internalCluster().startNode();
+        nodes.add(primaryNode);
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+                .build()
+        );
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        nodes.add(internalCluster().startNode());
+        ensureGreen(INDEX_NAME);
+
+        final long numDocs = scaledRandomIntBetween(50, 100);
+        for (int i = 0; i < numDocs; i++) {
+            index(INDEX_NAME, "doc", Integer.toString(i));
+        }
+        refresh(INDEX_NAME);
+
+        // search for all
+        SegmentReplicationStatsResponse segmentReplicationStatsResponse = client().admin()
+            .indices()
+            .prepareSegmentReplicationStats(INDEX_NAME)
+            .execute()
+            .actionGet();
+        assertTrue(segmentReplicationStatsResponse.getReplicationStats().isEmpty());
+    }
+
+    public void testSegmentReplicationNodeAndIndexStats() throws Exception {
+        logger.info("--> start primary node");
+        final String primaryNode = internalCluster().startNode();
+
+        logger.info("--> create index on node: {}", primaryNode);
+        assertAcked(prepareCreate(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)));
+
+        ensureYellow();
+        logger.info("--> start first replica node");
+        final String replicaNode1 = internalCluster().startNode();
+
+        logger.info("--> start second replica node");
+        final String replicaNode2 = internalCluster().startNode();
+
+        ensureGreen();
+        CountDownLatch latch = new CountDownLatch(1);
+        // block replication
+        try (final Releasable ignored = blockReplication(List.of(replicaNode1, replicaNode2), latch)) {
+            // index another doc while blocked, this would not get replicated to the replicas.
+            Thread indexingThread = new Thread(() -> {
+                client().prepareIndex(INDEX_NAME).setId("2").setSource("foo2", randomInt()).get();
+                refresh(INDEX_NAME);
+            });
+
+            indexingThread.start();
+            indexingThread.join();
+            latch.await();
+
+            NodesStatsResponse nodesStatsResponse = client().admin()
+                .cluster()
+                .prepareNodesStats()
+                .clear()
+                .setIndices(new CommonStatsFlags(CommonStatsFlags.Flag.Segments))
+                .get();
+
+            for (NodeStats nodeStats : nodesStatsResponse.getNodes()) {
+                ReplicationStats replicationStats = nodeStats.getIndices().getSegments().getReplicationStats();
+                // primary node - should hold replication statistics
+                if (nodeStats.getNode().getName().equals(primaryNode)) {
+                    assertTrue(replicationStats.getMaxBytesBehind() > 0);
+                    assertTrue(replicationStats.getTotalBytesBehind() > 0);
+                    assertTrue(replicationStats.getMaxReplicationLag() > 0);
+                    // 2 replicas so total bytes should be double of max
+                    assertEquals(replicationStats.getMaxBytesBehind() * 2, replicationStats.getTotalBytesBehind());
+                }
+                // replica nodes - should hold empty replication statistics
+                if (nodeStats.getNode().getName().equals(replicaNode1) || nodeStats.getNode().getName().equals(replicaNode2)) {
+                    assertEquals(0, replicationStats.getMaxBytesBehind());
+                    assertEquals(0, replicationStats.getTotalBytesBehind());
+                    assertEquals(0, replicationStats.getMaxReplicationLag());
+                }
+            }
+            // get replication statistics at index level
+            IndicesStatsResponse stats = client().admin().indices().prepareStats().execute().actionGet();
+
+            // stats should be of non-zero value when aggregated at index level
+            ReplicationStats indexReplicationStats = stats.getIndex(INDEX_NAME).getTotal().getSegments().getReplicationStats();
+            assertNotNull(indexReplicationStats);
+            assertTrue(indexReplicationStats.getMaxBytesBehind() > 0);
+            assertTrue(indexReplicationStats.getTotalBytesBehind() > 0);
+            assertTrue(indexReplicationStats.getMaxReplicationLag() > 0);
+            assertEquals(2 * indexReplicationStats.getMaxBytesBehind(), indexReplicationStats.getTotalBytesBehind());
+        }
+
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationSuiteIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationSuiteIT.java
new file mode 100644
index 0000000000000..800704eae7fa7
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationSuiteIT.java
@@ -0,0 +1,88 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, minNumDataNodes = 2)
+public class SegmentReplicationSuiteIT extends SegmentReplicationBaseIT {
+
+    @Before
+    public void setup() {
+        internalCluster().startClusterManagerOnlyNode();
+        createIndex(INDEX_NAME);
+    }
+
+    @Override
+    public Settings indexSettings() {
+        final Settings.Builder builder = Settings.builder()
+            .put(super.indexSettings())
+            // reset shard & replica count to random values set by OpenSearchIntegTestCase.
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numberOfShards())
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numberOfReplicas())
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+
+        // TODO: Randomly enable remote store on these tests.
+        return builder.build();
+    }
+
+    public void testBasicReplication() throws Exception {
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+        }
+        refresh();
+        ensureGreen(INDEX_NAME);
+        verifyStoreContent();
+    }
+
+    public void testDropRandomNodeDuringReplication() throws Exception {
+        internalCluster().ensureAtLeastNumDataNodes(2);
+        internalCluster().startClusterManagerOnlyNodes(1);
+
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+        }
+        refresh();
+
+        internalCluster().restartRandomDataNode();
+
+        ensureYellow(INDEX_NAME);
+        client().prepareIndex(INDEX_NAME).setId(Integer.toString(docCount)).setSource("field", "value" + docCount).execute().get();
+        internalCluster().startDataOnlyNode();
+        client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).actionGet();
+    }
+
+    public void testDeleteIndexWhileReplicating() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+        }
+        refresh(INDEX_NAME);
+        client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).actionGet();
+    }
+
+    public void testFullRestartDuringReplication() throws Exception {
+        internalCluster().startNode();
+        final int docCount = scaledRandomIntBetween(10, 200);
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().get();
+        }
+        refresh(INDEX_NAME);
+        internalCluster().fullRestart();
+        ensureGreen(INDEX_NAME);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/settings/ArchivedIndexSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/settings/ArchivedIndexSettingsIT.java
new file mode 100644
index 0000000000000..8dc343abf8da2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/settings/ArchivedIndexSettingsIT.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.settings;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
+import static org.hamcrest.Matchers.startsWith;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, supportsDedicatedMasters = false)
+public class ArchivedIndexSettingsIT extends OpenSearchIntegTestCase {
+    private volatile boolean installPlugin;
+
+    public void testArchiveSettings() throws Exception {
+        installPlugin = true;
+        // Set up the cluster with an index containing dummy setting(owned by dummy plugin)
+        String oldClusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        String oldDataNode = internalCluster().startDataOnlyNode();
+        assertEquals(2, internalCluster().numDataAndClusterManagerNodes());
+        createIndex("test");
+        ensureYellow();
+        // Add a dummy setting
+        client().admin()
+            .indices()
+            .prepareUpdateSettings("test")
+            .setSettings(Settings.builder().put("index.dummy", "foobar").put("index.dummy2", "foobar"))
+            .execute()
+            .actionGet();
+
+        // Remove dummy plugin and replace the cluster manager node so that the stale plugin setting moves to "archived".
+        installPlugin = false;
+        String newClusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(oldClusterManagerNode));
+        internalCluster().restartNode(newClusterManagerNode);
+
+        // Verify that archived settings exists.
+        assertBusy(() -> {
+            // Verify that cluster state is in recovered state.
+            assertFalse(client().admin().cluster().prepareState().get().getState().blocks().hasGlobalBlock(STATE_NOT_RECOVERED_BLOCK));
+            assertTrue(
+                client().admin()
+                    .indices()
+                    .prepareGetSettings("test")
+                    .get()
+                    .getIndexToSettings()
+                    .get("test")
+                    .hasValue("archived.index.dummy")
+            );
+            assertTrue(
+                client().admin()
+                    .indices()
+                    .prepareGetSettings("test")
+                    .get()
+                    .getIndexToSettings()
+                    .get("test")
+                    .hasValue("archived.index.dummy2")
+            );
+        }, 30, TimeUnit.SECONDS);
+
+        // Archived setting update should fail on open index.
+        IllegalArgumentException exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(Settings.builder().putNull("archived.index.dummy"))
+                .execute()
+                .actionGet()
+        );
+        assertThat(
+            exception.getMessage(),
+            startsWith("Can't update non dynamic settings [[archived.index.dummy]] for open indices [[test")
+        );
+
+        // close the index.
+        client().admin().indices().prepareClose("test").get();
+
+        // Remove archived.index.dummy explicitly.
+        assertTrue(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(Settings.builder().putNull("archived.index.dummy"))
+                .execute()
+                .actionGet()
+                .isAcknowledged()
+        );
+
+        // Remove archived.index.dummy2 using wildcard.
+        assertTrue(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("test")
+                .setSettings(Settings.builder().putNull("archived.*"))
+                .execute()
+                .actionGet()
+                .isAcknowledged()
+        );
+
+        // Verify that archived settings are cleaned up successfully.
+        assertFalse(
+            client().admin().indices().prepareGetSettings("test").get().getIndexToSettings().get("test").hasValue("archived.index.dummy")
+        );
+        assertFalse(
+            client().admin().indices().prepareGetSettings("test").get().getIndexToSettings().get("test").hasValue("archived.index.dummy2")
+        );
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return installPlugin ? Arrays.asList(DummySettingPlugin.class) : Collections.emptyList();
+    }
+
+    public static class DummySettingPlugin extends Plugin {
+        public static final Setting<String> DUMMY_SETTING = Setting.simpleString(
+            "index.dummy",
+            Setting.Property.IndexScope,
+            Setting.Property.Dynamic
+        );
+        public static final Setting<String> DUMMY_SETTING2 = Setting.simpleString(
+            "index.dummy2",
+            Setting.Property.IndexScope,
+            Setting.Property.Dynamic
+        );
+
+        @Override
+        public List<Setting<?>> getSettings() {
+            return Arrays.asList(DUMMY_SETTING, DUMMY_SETTING2);
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateNumberOfReplicasIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateNumberOfReplicasIT.java
index f78ecd82834c2..c73168ec6ad17 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateNumberOfReplicasIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateNumberOfReplicasIT.java
@@ -33,9 +33,11 @@
 package org.opensearch.indices.settings;
 
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Priority;
@@ -606,4 +608,135 @@ public void testUpdateNumberOfReplicasAllowNoIndices() {
         assertThat(numberOfReplicas, equalTo(0));
     }
 
+    public void testAwarenessReplicaBalance() {
+        createIndex("aware-replica", Settings.builder().put("index.number_of_replicas", 0).build());
+        createIndex(".system-index", Settings.builder().put("index.number_of_replicas", 0).build());
+        manageReplicaBalanceSetting(true);
+        int updated = 0;
+
+        try {
+            // replica count of 1 is ideal
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+                .execute()
+                .actionGet();
+            updated++;
+
+            // Since auto expand replica setting take precedence, this should pass
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2)
+                        .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+                )
+                .execute()
+                .actionGet();
+            updated++;
+
+            // system index - should be able to update
+            client().admin()
+                .indices()
+                .prepareUpdateSettings(".system-index")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2))
+                .execute()
+                .actionGet();
+            updated++;
+
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2))
+                .execute()
+                .actionGet();
+            fail("should have thrown an exception about the replica count");
+
+        } catch (IllegalArgumentException e) {
+            assertEquals(
+                "Validation Failed: 1: expected total copies needs to be a multiple of total awareness attributes [2];",
+                e.getMessage()
+            );
+            assertEquals(3, updated);
+        } finally {
+            manageReplicaBalanceSetting(false);
+        }
+    }
+
+    public void testAwarenessReplicaBalanceWithUseZoneForDefaultReplicaCount() {
+        createIndex("aware-replica", Settings.builder().put("index.number_of_replicas", 0).build());
+        createIndex(".system-index", Settings.builder().put("index.number_of_replicas", 0).build());
+        DeleteIndexTemplateRequestBuilder deleteTemplate = client().admin().indices().prepareDeleteTemplate("random_index_template");
+        assertAcked(deleteTemplate.execute().actionGet());
+        manageReplicaSettingForDefaultReplica(true);
+        int updated = 0;
+
+        try {
+
+            // replica count should not be changed and we should see the original replica count
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(Settings.builder().put("refresh_interval", "1s"))
+                .execute()
+                .actionGet();
+            updated++;
+
+            final ClusterState state = client().admin().cluster().prepareState().get().getState();
+            final IndexMetadata newIndex = state.metadata().index("aware-replica");
+            assertThat(newIndex.getNumberOfReplicas(), equalTo(0));
+
+            // replica count of 2 is ideal
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2))
+                .execute()
+                .actionGet();
+            updated++;
+
+            // Since auto expand replica setting take precedence, this should pass
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(
+                    Settings.builder()
+                        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                        .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-2")
+                )
+                .execute()
+                .actionGet();
+            updated++;
+
+            // system index - should be able to update
+            client().admin()
+                .indices()
+                .prepareUpdateSettings(".system-index")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 3))
+                .execute()
+                .actionGet();
+            updated++;
+
+            client().admin()
+                .indices()
+                .prepareUpdateSettings("aware-replica")
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+                .execute()
+                .actionGet();
+            fail("should have thrown an exception about the replica count");
+
+        } catch (IllegalArgumentException e) {
+            assertEquals(
+                "Validation Failed: 1: expected total copies needs to be a multiple of total awareness attributes [3];",
+                e.getMessage()
+            );
+            assertEquals(4, updated);
+        } finally {
+            manageReplicaSettingForDefaultReplica(false);
+            randomIndexTemplate();
+        }
+    }
+
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateSettingsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateSettingsIT.java
index 6dab7781e08db..6e94c50eec42a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateSettingsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/settings/UpdateSettingsIT.java
@@ -136,11 +136,9 @@ public static class DummySettingPlugin extends Plugin {
 
         @Override
         public void onIndexModule(IndexModule indexModule) {
-            indexModule.addSettingsUpdateConsumer(
-                DUMMY_SETTING,
-                (s) -> {},
-                (s) -> { if (s.equals("boom")) throw new IllegalArgumentException("this setting goes boom"); }
-            );
+            indexModule.addSettingsUpdateConsumer(DUMMY_SETTING, (s) -> {}, (s) -> {
+                if (s.equals("boom")) throw new IllegalArgumentException("this setting goes boom");
+            });
         }
 
         @Override
@@ -836,7 +834,7 @@ private void runTestDefaultNumberOfReplicasTest(final boolean closeIndex) {
 
     public void testNoopUpdate() {
         internalCluster().ensureAtLeastNumDataNodes(2);
-        final ClusterService clusterService = internalCluster().getMasterNodeInstance(ClusterService.class);
+        final ClusterService clusterService = internalCluster().getClusterManagerNodeInstance(ClusterService.class);
         assertAcked(
             client().admin()
                 .indices()
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexDisableCloseAllIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexDisableCloseAllIT.java
index 9fa78811017be..3579ec61f0120 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexDisableCloseAllIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexDisableCloseAllIT.java
@@ -36,7 +36,6 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
 import org.junit.After;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexIT.java
index 41749a9bfd0f4..ae88dd76d54e0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseIndexIT.java
@@ -46,9 +46,9 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
@@ -56,8 +56,8 @@
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.test.BackgroundIndexer;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -462,7 +462,7 @@ public void testRecoverExistingReplica() throws Exception {
         internalCluster().ensureAtLeastNumDataNodes(2);
         List<String> dataNodes = randomSubsetOf(
             2,
-            Sets.newHashSet(clusterService().state().nodes().getDataNodes().valuesIt())
+            Sets.newHashSet(clusterService().state().nodes().getDataNodes().values().iterator())
                 .stream()
                 .map(DiscoveryNode::getName)
                 .collect(Collectors.toSet())
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseWhileRelocatingShardsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseWhileRelocatingShardsIT.java
index caf741e9b8882..d6dce78061a7a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseWhileRelocatingShardsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/CloseWhileRelocatingShardsIT.java
@@ -48,7 +48,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.recovery.PeerRecoverySourceService;
 import org.opensearch.indices.recovery.StartRecoveryRequest;
 import org.opensearch.plugins.Plugin;
@@ -147,10 +147,13 @@ public void testCloseWhileRelocatingShards() throws Exception {
         );
 
         final String targetNode = internalCluster().startDataOnlyNode();
-        ensureClusterSizeConsistency(); // wait for the master to finish processing join.
+        ensureClusterSizeConsistency(); // wait for the cluster-manager to finish processing join.
 
         try {
-            final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, internalCluster().getMasterName());
+            final ClusterService clusterService = internalCluster().getInstance(
+                ClusterService.class,
+                internalCluster().getClusterManagerName()
+            );
             final ClusterState state = clusterService.state();
             final CountDownLatch latch = new CountDownLatch(indices.length);
             final CountDownLatch release = new CountDownLatch(indices.length);
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/OpenCloseIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/OpenCloseIndexIT.java
index ca1e1399f8fdc..0bf561c606a2d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/OpenCloseIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/OpenCloseIndexIT.java
@@ -44,12 +44,11 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.IOException;
@@ -301,16 +300,15 @@ public void testOpenWaitingForActiveShardsFailed() throws Exception {
     }
 
     public void testOpenCloseWithDocs() throws IOException, ExecutionException, InterruptedException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("test")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("test")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertAcked(client().admin().indices().prepareCreate("test").setMapping(mapping));
         ensureGreen();
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/ReopenWhileClosingIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/ReopenWhileClosingIT.java
index 38e50a64c8105..e93bd68dca583 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/ReopenWhileClosingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/ReopenWhileClosingIT.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.indices.state;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.indices.close.CloseIndexResponse;
 import org.opensearch.action.admin.indices.close.TransportVerifyShardBeforeCloseAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Glob;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.RunOnce;
+import org.opensearch.core.common.Strings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
@@ -150,7 +150,7 @@ private void createIndexWithDocs(final String indexName, final Collection<String
     private Releasable interceptVerifyShardBeforeCloseActions(final String indexPattern, final Runnable onIntercept) {
         final MockTransportService mockTransportService = (MockTransportService) internalCluster().getInstance(
             TransportService.class,
-            internalCluster().getMasterName()
+            internalCluster().getClusterManagerName()
         );
 
         final CountDownLatch release = new CountDownLatch(1);
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/state/SimpleIndexStateIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/state/SimpleIndexStateIT.java
index b75e36efe1f2f..6411598abd938 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/state/SimpleIndexStateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/state/SimpleIndexStateIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
@@ -49,7 +48,6 @@
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.notNullValue;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/stats/IndexStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/stats/IndexStatsIT.java
index be8a1ad4f0c61..0967acb37d3e8 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/stats/IndexStatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/stats/IndexStatsIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.indices.stats;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -49,33 +51,41 @@
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.SearchType;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
+import org.opensearch.action.support.WriteRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.UUIDs;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
 import org.opensearch.index.MergeSchedulerConfig;
+import org.opensearch.index.TieredMergePolicyProvider;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.index.remote.RemoteSegmentStats;
 import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.translog.RemoteTranslogStats;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesQueryCache;
 import org.opensearch.indices.IndicesRequestCache;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -98,6 +108,7 @@
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
@@ -111,7 +122,23 @@
 
 @ClusterScope(scope = Scope.SUITE, numDataNodes = 2, numClientNodes = 0)
 @SuppressCodecs("*") // requires custom completion format
-public class IndexStatsIT extends OpenSearchIntegTestCase {
+public class IndexStatsIT extends ParameterizedOpenSearchIntegTestCase {
+    public IndexStatsIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -562,8 +589,8 @@ public void testNonThrottleStats() throws Exception {
             prepareCreate("test").setSettings(
                 settingsBuilder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
-                    .put(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
-                    .put(MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
+                    .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
+                    .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
                     .put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "1")
                     .put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "10000")
             )
@@ -594,8 +621,8 @@ public void testThrottleStats() throws Exception {
             prepareCreate("test").setSettings(
                 settingsBuilder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
                     .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
-                    .put(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
-                    .put(MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
+                    .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
+                    .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
                     .put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "1")
                     .put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "1")
                     .put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Translog.Durability.ASYNC.name())
@@ -1011,7 +1038,10 @@ public void testCompletionFieldsParam() throws Exception {
         );
         ensureGreen();
 
-        client().prepareIndex("test1").setId(Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", XContentType.JSON).get();
+        client().prepareIndex("test1")
+            .setId(Integer.toString(1))
+            .setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", MediaTypeRegistry.JSON)
+            .get();
         refresh();
 
         IndicesStatsRequestBuilder builder = client().admin().indices().prepareStats();
@@ -1319,7 +1349,7 @@ public void testFilterCacheStats() throws Exception {
      * Test that we can safely concurrently index and get stats. This test was inspired by a serialization issue that arose due to a race
      * getting doc stats during heavy indexing. The race could lead to deleted docs being negative which would then be serialized as a
      * variable-length long. Since serialization of negative longs using a variable-length format was unsupported
-     * ({@link org.opensearch.common.io.stream.StreamOutput#writeVLong(long)}), the stream would become corrupted. Here, we want to test
+     * ({@link StreamOutput#writeVLong(long)}), the stream would become corrupted. Here, we want to test
      * that we can continue to get stats while indexing.
      */
     public void testConcurrentIndexingAndStatsRequests() throws BrokenBarrierException, InterruptedException, ExecutionException {
@@ -1356,7 +1386,7 @@ public void testConcurrentIndexingAndStatsRequests() throws BrokenBarrierExcepti
                 }
                 while (!stop.get()) {
                     final String id = Integer.toString(idGenerator.incrementAndGet());
-                    final IndexResponse response = client().prepareIndex("test").setId(id).setSource("{}", XContentType.JSON).get();
+                    final IndexResponse response = client().prepareIndex("test").setId(id).setSource("{}", MediaTypeRegistry.JSON).get();
                     assertThat(response.getResult(), equalTo(DocWriteResponse.Result.CREATED));
                 }
             });
@@ -1414,6 +1444,50 @@ public void testConcurrentIndexingAndStatsRequests() throws BrokenBarrierExcepti
         assertThat(executionFailures.get(), emptyCollectionOf(Exception.class));
     }
 
+    public void testZeroRemoteStoreStatsOnNonRemoteStoreIndex() {
+        String indexName = "test-index";
+        createIndex(indexName, Settings.builder().put("index.number_of_shards", 1).put("index.number_of_replicas", 0).build());
+        ensureGreen(indexName);
+        assertEquals(
+            RestStatus.CREATED,
+            client().prepareIndex(indexName)
+                .setId(UUIDs.randomBase64UUID())
+                .setSource("field", "value1", "field2", "value1")
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .get()
+                .status()
+        );
+        ShardStats shard = client().admin().indices().prepareStats(indexName).setSegments(true).setTranslog(true).get().getShards()[0];
+        RemoteSegmentStats remoteSegmentStatsFromIndexStats = shard.getStats().getSegments().getRemoteSegmentStats();
+        assertZeroRemoteSegmentStats(remoteSegmentStatsFromIndexStats);
+        RemoteTranslogStats remoteTranslogStatsFromIndexStats = shard.getStats().getTranslog().getRemoteTranslogStats();
+        assertZeroRemoteTranslogStats(remoteTranslogStatsFromIndexStats);
+
+        NodesStatsResponse nodesStatsResponse = client().admin().cluster().prepareNodesStats(primaryNodeName(indexName)).get();
+        RemoteSegmentStats remoteSegmentStatsFromNodesStats = nodesStatsResponse.getNodes()
+            .get(0)
+            .getIndices()
+            .getSegments()
+            .getRemoteSegmentStats();
+        assertZeroRemoteSegmentStats(remoteSegmentStatsFromNodesStats);
+        RemoteTranslogStats remoteTranslogStatsFromNodesStats = nodesStatsResponse.getNodes()
+            .get(0)
+            .getIndices()
+            .getTranslog()
+            .getRemoteTranslogStats();
+        assertZeroRemoteTranslogStats(remoteTranslogStatsFromNodesStats);
+    }
+
+    private void assertZeroRemoteSegmentStats(RemoteSegmentStats remoteSegmentStats) {
+        // Compare with fresh object because all values default to 0 in default fresh object
+        assertEquals(new RemoteSegmentStats(), remoteSegmentStats);
+    }
+
+    private void assertZeroRemoteTranslogStats(RemoteTranslogStats remoteTranslogStats) {
+        // Compare with fresh object because all values default to 0 in default fresh object
+        assertEquals(new RemoteTranslogStats(), remoteTranslogStats);
+    }
+
     /**
      * Persist the global checkpoint on all shards of the given index into disk.
      * This makes sure that the persisted global checkpoint on those shards will equal to the in-memory value.
@@ -1430,4 +1504,37 @@ private void persistGlobalCheckpoint(String index) throws Exception {
             }
         }
     }
+
+    public void testSegmentReplicationStats() {
+        String indexName = "test-index";
+        createIndex(
+            indexName,
+            Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 1).build()
+        );
+
+        ensureGreen(indexName);
+
+        IndicesStatsRequestBuilder builder = client().admin().indices().prepareStats();
+        IndicesStatsResponse stats = builder.execute().actionGet();
+
+        // document replication enabled index should return empty segment replication stats
+        assertNotNull(stats.getIndex(indexName).getTotal().getSegments().getReplicationStats());
+
+        indexName = "test-index2";
+        createIndex(
+            indexName,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .build()
+        );
+        ensureGreen(indexName);
+
+        builder = client().admin().indices().prepareStats();
+        stats = builder.execute().actionGet();
+
+        // segment replication enabled index should return segment replication stats
+        assertNotNull(stats.getIndex(indexName).getTotal().getSegments().getReplicationStats());
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/store/IndicesStoreIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/store/IndicesStoreIntegrationIT.java
index b85afa80496d0..00f74559ebbf6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/store/IndicesStoreIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/store/IndicesStoreIntegrationIT.java
@@ -52,17 +52,17 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.disruption.BlockClusterStateProcessing;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.ConnectTransportException;
@@ -79,8 +79,8 @@
 import java.util.concurrent.TimeUnit;
 
 import static java.lang.Thread.sleep;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -105,14 +105,14 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
 
     @Override
     protected void ensureClusterStateConsistency() throws IOException {
-        // testShardActiveElseWhere might change the state of a non-master node
+        // testShardActiveElseWhere might change the state of a non-cluster-manager node
         // so we cannot check state consistency of this cluster
     }
 
     public void testIndexCleanup() throws Exception {
         internalCluster().startNode(nonDataNode());
-        final String node_1 = internalCluster().startNode(nonMasterNode());
-        final String node_2 = internalCluster().startNode(nonMasterNode());
+        final String node_1 = internalCluster().startNode(nonClusterManagerNode());
+        final String node_2 = internalCluster().startNode(nonClusterManagerNode());
         logger.info("--> creating index [test] with one shard and on replica");
         assertAcked(
             prepareCreate("test").setSettings(
@@ -133,7 +133,7 @@ public void testIndexCleanup() throws Exception {
         assertThat(Files.exists(indexDirectory(node_2, index)), equalTo(true));
 
         logger.info("--> starting node server3");
-        final String node_3 = internalCluster().startNode(nonMasterNode());
+        final String node_3 = internalCluster().startNode(nonClusterManagerNode());
         logger.info("--> running cluster_health");
         ClusterHealthResponse clusterHealth = client().admin()
             .cluster()
@@ -345,7 +345,7 @@ public void testShardsCleanup() throws Exception {
     }
 
     public void testShardActiveElsewhereDoesNotDeleteAnother() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final List<String> nodes = internalCluster().startDataOnlyNodes(4);
 
         final String node1 = nodes.get(0);
@@ -459,11 +459,11 @@ public void testShardActiveElsewhereDoesNotDeleteAnother() throws Exception {
     public void testShardActiveElseWhere() throws Exception {
         List<String> nodes = internalCluster().startNodes(2);
 
-        final String masterNode = internalCluster().getMasterName();
-        final String nonMasterNode = nodes.get(0).equals(masterNode) ? nodes.get(1) : nodes.get(0);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        final String nonClusterManagerNode = nodes.get(0).equals(clusterManagerNode) ? nodes.get(1) : nodes.get(0);
 
-        final String masterId = internalCluster().clusterService(masterNode).localNode().getId();
-        final String nonMasterId = internalCluster().clusterService(nonMasterNode).localNode().getId();
+        final String clusterManagerId = internalCluster().clusterService(clusterManagerNode).localNode().getId();
+        final String nonClusterManagerId = internalCluster().clusterService(nonClusterManagerNode).localNode().getId();
 
         final int numShards = scaledRandomIntBetween(2, 10);
         assertAcked(
@@ -476,14 +476,14 @@ public void testShardActiveElseWhere() throws Exception {
         waitNoPendingTasksOnAll();
         ClusterStateResponse stateResponse = client().admin().cluster().prepareState().get();
         final Index index = stateResponse.getState().metadata().index("test").getIndex();
-        RoutingNode routingNode = stateResponse.getState().getRoutingNodes().node(nonMasterId);
+        RoutingNode routingNode = stateResponse.getState().getRoutingNodes().node(nonClusterManagerId);
         final int[] node2Shards = new int[routingNode.numberOfOwningShards()];
         int i = 0;
         for (ShardRouting shardRouting : routingNode) {
             node2Shards[i] = shardRouting.shardId().id();
             i++;
         }
-        logger.info("Node [{}] has shards: {}", nonMasterNode, Arrays.toString(node2Shards));
+        logger.info("Node [{}] has shards: {}", nonClusterManagerNode, Arrays.toString(node2Shards));
 
         // disable relocations when we do this, to make sure the shards are not relocated from node2
         // due to rebalancing, and delete its content
@@ -496,14 +496,14 @@ public void testShardActiveElseWhere() throws Exception {
             )
             .get();
 
-        ClusterApplierService clusterApplierService = internalCluster().getInstance(ClusterService.class, nonMasterNode)
+        ClusterApplierService clusterApplierService = internalCluster().getInstance(ClusterService.class, nonClusterManagerNode)
             .getClusterApplierService();
         ClusterState currentState = clusterApplierService.state();
         IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(index);
         for (int j = 0; j < numShards; j++) {
             indexRoutingTableBuilder.addIndexShard(
                 new IndexShardRoutingTable.Builder(new ShardId(index, j)).addShard(
-                    TestShardRouting.newShardRouting("test", j, masterId, true, ShardRoutingState.STARTED)
+                    TestShardRouting.newShardRouting("test", j, clusterManagerId, true, ShardRoutingState.STARTED)
                 ).build()
             );
         }
@@ -528,7 +528,7 @@ public void onFailure(String source, Exception e) {
         waitNoPendingTasksOnAll();
         logger.info("Checking if shards aren't removed");
         for (int shard : node2Shards) {
-            assertShardExists(nonMasterNode, index, shard);
+            assertShardExists(nonClusterManagerNode, index, shard);
         }
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/template/IndexTemplateBlocksIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/template/IndexTemplateBlocksIT.java
index 21e3e58d4d091..f2852de865b27 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/template/IndexTemplateBlocksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/template/IndexTemplateBlocksIT.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
-
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/template/SimpleIndexTemplateIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/template/SimpleIndexTemplateIT.java
index 0e15a0c895432..2421b97991b1c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/template/SimpleIndexTemplateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/template/SimpleIndexTemplateIT.java
@@ -38,25 +38,25 @@
 import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
 import org.opensearch.action.admin.indices.template.put.PutIndexTemplateRequestBuilder;
-
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.indices.InvalidAliasNameException;
+import org.opensearch.indices.InvalidIndexTemplateException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.junit.After;
 
 import java.io.IOException;
@@ -477,7 +477,7 @@ public void testBrokenMapping() throws Exception {
                 .indices()
                 .preparePutTemplate("template_1")
                 .setPatterns(Collections.singletonList("te*"))
-                .setMapping("{\"foo\": \"abcde\"}", XContentType.JSON)
+                .setMapping("{\"foo\": \"abcde\"}", MediaTypeRegistry.JSON)
                 .get()
         );
         assertThat(e.getMessage(), containsString("Failed to parse mapping "));
@@ -590,7 +590,7 @@ public void testIndexTemplateWithAliasesInSource() {
                         + "    }\n"
                         + "}"
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
@@ -802,8 +802,8 @@ public void testStrictAliasParsingInIndicesCreatedViaTemplates() throws Exceptio
             .addAlias(new Alias("alias4").filter(termQuery("field", "value")))
             .get();
 
-        client().prepareIndex("a1").setId("test").setSource("{}", XContentType.JSON).get();
-        BulkResponse response = client().prepareBulk().add(new IndexRequest("a2").id("test").source("{}", XContentType.JSON)).get();
+        client().prepareIndex("a1").setId("test").setSource("{}", MediaTypeRegistry.JSON).get();
+        BulkResponse response = client().prepareBulk().add(new IndexRequest("a2").id("test").source("{}", MediaTypeRegistry.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getIndex(), equalTo("a2"));
@@ -818,9 +818,9 @@ public void testStrictAliasParsingInIndicesCreatedViaTemplates() throws Exceptio
         // So the aliases defined in the index template for this index will not fail
         // even though the fields in the alias fields don't exist yet and indexing into
         // an index that doesn't exist yet will succeed
-        client().prepareIndex("b1").setId("test").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("b1").setId("test").setSource("{}", MediaTypeRegistry.JSON).get();
 
-        response = client().prepareBulk().add(new IndexRequest("b2").id("test").source("{}", XContentType.JSON)).get();
+        response = client().prepareBulk().add(new IndexRequest("b2").id("test").source("{}", MediaTypeRegistry.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getId(), equalTo("test"));
@@ -853,7 +853,7 @@ public void testCombineTemplates() throws Exception {
                     + "            }\n"
                     + "         }\n"
                     + "    }\n",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
@@ -991,7 +991,7 @@ public void testPartitionedTemplate() throws Exception {
                 .indices()
                 .preparePutTemplate("template_2")
                 .setPatterns(Collections.singletonList("te*"))
-                .setMapping("{\"_routing\":{\"required\":false}}", XContentType.JSON)
+                .setMapping("{\"_routing\":{\"required\":false}}", MediaTypeRegistry.JSON)
                 .setSettings(Settings.builder().put("index.number_of_shards", "6").put("index.routing_partition_size", "3"))
                 .get()
         );
@@ -1029,4 +1029,52 @@ public void testPartitionedTemplate() throws Exception {
         GetSettingsResponse getSettingsResponse = client().admin().indices().prepareGetSettings("test_good").get();
         assertEquals("6", getSettingsResponse.getIndexToSettings().get("test_good").get("index.routing_partition_size"));
     }
+
+    public void testAwarenessReplicaBalance() throws IOException {
+        manageReplicaSettingForDefaultReplica(true);
+        int updated = 0;
+        try {
+            client().admin()
+                .indices()
+                .preparePutTemplate("template_1")
+                .setPatterns(Arrays.asList("a*", "b*"))
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 2))
+                .get();
+            updated++;
+
+            client().admin()
+                .indices()
+                .preparePutTemplate("template_1")
+                .setPatterns(Arrays.asList("a*", "b*"))
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 4))
+                .get();
+            updated++;
+
+            client().admin()
+                .indices()
+                .preparePutTemplate("template_1")
+                .setPatterns(Arrays.asList("a*", "b*"))
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-2"))
+                .get();
+            updated++;
+
+            client().admin()
+                .indices()
+                .preparePutTemplate("template_1")
+                .setPatterns(Arrays.asList("a*", "b*"))
+                .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0))
+                .get();
+
+            fail("should have thrown an exception about the replica  count");
+        } catch (InvalidIndexTemplateException e) {
+            assertEquals(
+                "index_template [template_1] invalid, cause [Validation Failed: 1: expected total copies needs to be a multiple of total awareness attributes [3];]",
+                e.getMessage()
+            );
+            assertEquals(3, updated);
+        } finally {
+            manageReplicaSettingForDefaultReplica(false);
+        }
+    }
+
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/ingest/IngestClientIT.java b/server/src/internalClusterTest/java/org/opensearch/ingest/IngestClientIT.java
index 2f666bbd65d4d..e2cedea331412 100644
--- a/server/src/internalClusterTest/java/org/opensearch/ingest/IngestClientIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/ingest/IngestClientIT.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.ingest;
 
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkRequest;
@@ -51,10 +51,10 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.client.Requests;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
@@ -100,7 +100,7 @@ public void testSimulate() throws Exception {
                 .endArray()
                 .endObject()
         );
-        client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
+        client().admin().cluster().preparePutPipeline("_id", pipelineSource, MediaTypeRegistry.JSON).get();
         GetPipelineResponse getResponse = client().admin().cluster().prepareGetPipeline("_id").get();
         assertThat(getResponse.isFound(), is(true));
         assertThat(getResponse.pipelines().size(), equalTo(1));
@@ -111,7 +111,6 @@ public void testSimulate() throws Exception {
                 .startArray("docs")
                 .startObject()
                 .field("_index", "index")
-                .field("_type", "type")
                 .field("_id", "id")
                 .startObject("_source")
                 .field("foo", "bar")
@@ -123,9 +122,9 @@ public void testSimulate() throws Exception {
         );
         SimulatePipelineResponse response;
         if (randomBoolean()) {
-            response = client().admin().cluster().prepareSimulatePipeline(bytes, XContentType.JSON).setId("_id").get();
+            response = client().admin().cluster().prepareSimulatePipeline(bytes, MediaTypeRegistry.JSON).setId("_id").get();
         } else {
-            SimulatePipelineRequest request = new SimulatePipelineRequest(bytes, XContentType.JSON);
+            SimulatePipelineRequest request = new SimulatePipelineRequest(bytes, MediaTypeRegistry.JSON);
             request.setId("_id");
             response = client().admin().cluster().simulatePipeline(request).get();
         }
@@ -161,7 +160,7 @@ public void testBulkWithIngestFailures() throws Exception {
                 .endArray()
                 .endObject()
         );
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, MediaTypeRegistry.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
         int numRequests = scaledRandomIntBetween(32, 128);
@@ -212,7 +211,7 @@ public void testBulkWithUpsert() throws Exception {
                 .endArray()
                 .endObject()
         );
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, MediaTypeRegistry.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
         BulkRequest bulkRequest = new BulkRequest();
@@ -221,7 +220,7 @@ public void testBulkWithUpsert() throws Exception {
         bulkRequest.add(indexRequest);
         UpdateRequest updateRequest = new UpdateRequest("index", "2");
         updateRequest.doc("{}", Requests.INDEX_CONTENT_TYPE);
-        updateRequest.upsert("{\"field1\":\"upserted_val\"}", XContentType.JSON).upsertRequest().setPipeline("_id");
+        updateRequest.upsert("{\"field1\":\"upserted_val\"}", MediaTypeRegistry.JSON).upsertRequest().setPipeline("_id");
         bulkRequest.add(updateRequest);
 
         BulkResponse response = client().bulk(bulkRequest).actionGet();
@@ -247,7 +246,7 @@ public void test() throws Exception {
                 .endArray()
                 .endObject()
         );
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, MediaTypeRegistry.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
         GetPipelineRequest getPipelineRequest = new GetPipelineRequest("_id");
@@ -291,7 +290,7 @@ public void testPutWithPipelineFactoryError() throws Exception {
                 .endArray()
                 .endObject()
         );
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id2", source, XContentType.JSON);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id2", source, MediaTypeRegistry.JSON);
         Exception e = expectThrows(
             OpenSearchParseException.class,
             () -> client().admin().cluster().putPipeline(putPipelineRequest).actionGet()
@@ -302,8 +301,8 @@ public void testPutWithPipelineFactoryError() throws Exception {
         assertFalse(response.isFound());
     }
 
-    public void testWithDedicatedMaster() throws Exception {
-        String masterOnlyNode = internalCluster().startMasterOnlyNode();
+    public void testWithDedicatedClusterManager() throws Exception {
+        String clusterManagerOnlyNode = internalCluster().startClusterManagerOnlyNode();
         BytesReference source = BytesReference.bytes(
             jsonBuilder().startObject()
                 .field("description", "my_pipeline")
@@ -315,10 +314,10 @@ public void testWithDedicatedMaster() throws Exception {
                 .endArray()
                 .endObject()
         );
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, MediaTypeRegistry.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
-        BulkItemResponse item = client(masterOnlyNode).prepareBulk()
+        BulkItemResponse item = client(clusterManagerOnlyNode).prepareBulk()
             .add(client().prepareIndex("test").setSource("field", "value2", "drop", true).setPipeline("_id"))
             .get()
             .getItems()[0];
@@ -341,7 +340,7 @@ public void testPipelineOriginHeader() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("1", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("1", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
         {
@@ -358,7 +357,7 @@ public void testPipelineOriginHeader() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("2", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("2", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
         {
@@ -374,13 +373,13 @@ public void testPipelineOriginHeader() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("3", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("3", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
 
         Exception e = expectThrows(Exception.class, () -> {
             IndexRequest indexRequest = new IndexRequest("test");
-            indexRequest.source("{}", XContentType.JSON);
+            indexRequest.source("{}", MediaTypeRegistry.JSON);
             indexRequest.setPipeline("1");
             client().index(indexRequest).get();
         });
@@ -414,7 +413,7 @@ public void testPipelineProcessorOnFailure() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("1", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("1", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
         {
@@ -431,7 +430,7 @@ public void testPipelineProcessorOnFailure() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("2", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("2", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
         {
@@ -447,11 +446,11 @@ public void testPipelineProcessorOnFailure() throws Exception {
                 source.endArray();
             }
             source.endObject();
-            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("3", BytesReference.bytes(source), XContentType.JSON);
+            PutPipelineRequest putPipelineRequest = new PutPipelineRequest("3", BytesReference.bytes(source), MediaTypeRegistry.JSON);
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         }
 
-        client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).setPipeline("1").get();
+        client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).setPipeline("1").get();
         Map<String, Object> inserted = client().prepareGet("test", "1").get().getSourceAsMap();
         assertThat(inserted.get("readme"), equalTo("pipeline with id [3] is a bad pipeline"));
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
index 1aed4de79cd63..38f1375bc7504 100644
--- a/server/src/internalClusterTest/java/org/opensearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.node.NodeService;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -84,20 +84,20 @@ public void testFailPipelineCreation() throws Exception {
         ensureStableCluster(2, node2);
 
         try {
-            client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
+            client().admin().cluster().preparePutPipeline("_id", pipelineSource, MediaTypeRegistry.JSON).get();
             fail("exception expected");
         } catch (OpenSearchParseException e) {
             assertThat(e.getMessage(), containsString("Processor type [test] is not installed on node"));
         }
     }
 
-    public void testFailPipelineCreationProcessorNotInstalledOnMasterNode() throws Exception {
+    public void testFailPipelineCreationProcessorNotInstalledOnClusterManagerNode() throws Exception {
         internalCluster().startNode();
         installPlugin = true;
         internalCluster().startNode();
 
         try {
-            client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
+            client().admin().cluster().preparePutPipeline("_id", pipelineSource, MediaTypeRegistry.JSON).get();
             fail("exception expected");
         } catch (OpenSearchParseException e) {
             assertThat(e.getMessage(), equalTo("No processor type exists with name [test]"));
@@ -110,7 +110,7 @@ public void testFailStartNode() throws Exception {
         installPlugin = true;
         String node1 = internalCluster().startNode();
 
-        AcknowledgedResponse response = client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
+        AcknowledgedResponse response = client().admin().cluster().preparePutPipeline("_id", pipelineSource, MediaTypeRegistry.JSON).get();
         assertThat(response.isAcknowledged(), is(true));
         Pipeline pipeline = internalCluster().getInstance(NodeService.class, node1).getIngestService().getPipeline("_id");
         assertThat(pipeline, notNullValue());
diff --git a/server/src/internalClusterTest/java/org/opensearch/mget/SimpleMgetIT.java b/server/src/internalClusterTest/java/org/opensearch/mget/SimpleMgetIT.java
index c9d18e64ca038..f77ae80a55276 100644
--- a/server/src/internalClusterTest/java/org/opensearch/mget/SimpleMgetIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/mget/SimpleMgetIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.mget;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.get.MultiGetItemResponse;
@@ -39,17 +41,21 @@
 import org.opensearch.action.get.MultiGetRequestBuilder;
 import org.opensearch.action.get.MultiGetResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Map;
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -57,7 +63,24 @@
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
 
-public class SimpleMgetIT extends OpenSearchIntegTestCase {
+public class SimpleMgetIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SimpleMgetIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testThatMgetShouldWorkWithOneIndexMissing() throws IOException {
         createIndex("test");
@@ -159,7 +182,7 @@ public void testThatSourceFilteringIsSupported() throws Exception {
                 .endObject()
         );
         for (int i = 0; i < 100; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource(sourceBytesRef, XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource(sourceBytesRef, MediaTypeRegistry.JSON).get();
         }
 
         MultiGetRequestBuilder request = client().prepareMultiGet();
diff --git a/server/src/internalClusterTest/java/org/opensearch/nodesinfo/SimpleNodesInfoIT.java b/server/src/internalClusterTest/java/org/opensearch/nodesinfo/SimpleNodesInfoIT.java
index 086badb52a46c..7e066a610b82c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/nodesinfo/SimpleNodesInfoIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/nodesinfo/SimpleNodesInfoIT.java
@@ -45,9 +45,7 @@
 import java.util.List;
 
 import static org.opensearch.action.admin.cluster.node.info.NodesInfoRequest.Metric.INDICES;
-
 import static org.opensearch.client.Requests.nodesInfoRequest;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.is;
diff --git a/server/src/internalClusterTest/java/org/opensearch/nodestats/NodeStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/nodestats/NodeStatsIT.java
new file mode 100644
index 0000000000000..f270cb1399072
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/nodestats/NodeStatsIT.java
@@ -0,0 +1,276 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.nodestats;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.DocWriteResponse;
+import org.opensearch.action.bulk.BulkItemResponse;
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.action.delete.DeleteRequest;
+import org.opensearch.action.delete.DeleteResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.update.UpdateRequest;
+import org.opensearch.action.update.UpdateResponse;
+import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.engine.DocumentMissingException;
+import org.opensearch.index.engine.VersionConflictEngineException;
+import org.opensearch.index.shard.IndexingStats.Stats.DocStatusStats;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.hamcrest.MatcherAssert;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static java.util.Collections.singletonMap;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+
+@ClusterScope(scope = Scope.TEST, numDataNodes = 1, numClientNodes = 0, supportsDedicatedMasters = false)
+public class NodeStatsIT extends OpenSearchIntegTestCase {
+
+    private final DocStatusStats expectedDocStatusStats = new DocStatusStats();
+    private static final String FIELD = "dummy_field";
+    private static final String VALUE = "dummy_value";
+    private static final Map<String, Object> SOURCE = singletonMap(FIELD, VALUE);
+
+    public void testNodeIndicesStatsDocStatusStatsIndexBulk() {
+        {  // Testing Index
+            final String INDEX = "test_index";
+            final String ID = "id";
+            {  // Testing Normal Index
+                IndexResponse response = client().index(new IndexRequest(INDEX).id(ID).source(SOURCE)).actionGet();
+                updateExpectedDocStatusCounter(response);
+
+                MatcherAssert.assertThat(response.getResult(), equalTo(DocWriteResponse.Result.CREATED));
+                assertDocStatusStats();
+            }
+            {  // Testing Missing Alias
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        IndexNotFoundException.class,
+                        () -> client().index(new IndexRequest(INDEX).id("missing_alias").setRequireAlias(true).source(SOURCE)).actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+            {
+                // Test Missing Pipeline: Ingestion failure, not Indexing failure
+                expectThrows(
+                    IllegalArgumentException.class,
+                    () -> client().index(new IndexRequest(INDEX).id("missing_pipeline").setPipeline("missing").source(SOURCE)).actionGet()
+                );
+                assertDocStatusStats();
+            }
+            {  // Testing Version Conflict
+                final String docId = "version_conflict";
+
+                updateExpectedDocStatusCounter(client().index(new IndexRequest(INDEX).id(docId).source(SOURCE)).actionGet());
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        VersionConflictEngineException.class,
+                        () -> client().index(new IndexRequest(INDEX).id(docId).source(SOURCE).setIfSeqNo(1L).setIfPrimaryTerm(99L))
+                            .actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+        }
+        {  // Testing Bulk
+            final String INDEX = "bulk_index";
+
+            int sizeOfIndexRequests = scaledRandomIntBetween(10, 20);
+            int sizeOfDeleteRequests = scaledRandomIntBetween(5, sizeOfIndexRequests);
+            int sizeOfNotFoundRequests = scaledRandomIntBetween(5, sizeOfIndexRequests);
+
+            BulkRequest bulkRequest = new BulkRequest();
+
+            for (int i = 0; i < sizeOfIndexRequests; ++i) {
+                bulkRequest.add(new IndexRequest(INDEX).id(String.valueOf(i)).source(SOURCE));
+            }
+
+            BulkResponse response = client().bulk(bulkRequest).actionGet();
+
+            MatcherAssert.assertThat(response.hasFailures(), equalTo(false));
+            MatcherAssert.assertThat(response.getItems().length, equalTo(sizeOfIndexRequests));
+
+            for (BulkItemResponse itemResponse : response.getItems()) {
+                updateExpectedDocStatusCounter(itemResponse.getResponse());
+            }
+
+            refresh(INDEX);
+            bulkRequest.requests().clear();
+
+            for (int i = 0; i < sizeOfDeleteRequests; ++i) {
+                bulkRequest.add(new DeleteRequest(INDEX, String.valueOf(i)));
+            }
+            for (int i = 0; i < sizeOfNotFoundRequests; ++i) {
+                bulkRequest.add(new DeleteRequest(INDEX, String.valueOf(25 + i)));
+            }
+
+            response = client().bulk(bulkRequest).actionGet();
+
+            MatcherAssert.assertThat(response.hasFailures(), equalTo(false));
+            MatcherAssert.assertThat(response.getItems().length, equalTo(sizeOfDeleteRequests + sizeOfNotFoundRequests));
+
+            for (BulkItemResponse itemResponse : response.getItems()) {
+                updateExpectedDocStatusCounter(itemResponse.getResponse());
+            }
+
+            refresh(INDEX);
+            assertDocStatusStats();
+        }
+    }
+
+    public void testNodeIndicesStatsDocStatusStatsCreateDeleteUpdate() {
+        {  // Testing Create
+            final String INDEX = "create_index";
+            final String ID = "id";
+            {  // Testing Creation
+                IndexResponse response = client().index(new IndexRequest(INDEX).id(ID).source(SOURCE).create(true)).actionGet();
+                updateExpectedDocStatusCounter(response);
+
+                MatcherAssert.assertThat(response.getResult(), equalTo(DocWriteResponse.Result.CREATED));
+                assertDocStatusStats();
+            }
+            {  // Testing Version Conflict
+                final String docId = "version_conflict";
+
+                updateExpectedDocStatusCounter(client().index(new IndexRequest(INDEX).id(docId).source(SOURCE)).actionGet());
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        VersionConflictEngineException.class,
+                        () -> client().index(new IndexRequest(INDEX).id(docId).source(SOURCE).create(true)).actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+        }
+        {  // Testing Delete
+            final String INDEX = "delete_index";
+            final String ID = "id";
+            {  // Testing Deletion
+                IndexResponse response = client().index(new IndexRequest(INDEX).id(ID).source(SOURCE)).actionGet();
+                updateExpectedDocStatusCounter(response);
+
+                DeleteResponse deleteResponse = client().delete(new DeleteRequest(INDEX, ID)).actionGet();
+                updateExpectedDocStatusCounter(deleteResponse);
+
+                MatcherAssert.assertThat(response.getSeqNo(), greaterThanOrEqualTo(0L));
+                MatcherAssert.assertThat(deleteResponse.getResult(), equalTo(DocWriteResponse.Result.DELETED));
+                assertDocStatusStats();
+            }
+            {  // Testing Non-Existing Doc
+                updateExpectedDocStatusCounter(client().delete(new DeleteRequest(INDEX, "does_not_exist")).actionGet());
+                assertDocStatusStats();
+            }
+            {  // Testing Version Conflict
+                final String docId = "version_conflict";
+
+                updateExpectedDocStatusCounter(client().index(new IndexRequest(INDEX).id(docId).source(SOURCE)).actionGet());
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        VersionConflictEngineException.class,
+                        () -> client().delete(new DeleteRequest(INDEX, docId).setIfSeqNo(2L).setIfPrimaryTerm(99L)).actionGet()
+                    )
+                );
+
+                assertDocStatusStats();
+            }
+        }
+        {  // Testing Update
+            final String INDEX = "update_index";
+            final String ID = "id";
+            {  // Testing Not Found
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        DocumentMissingException.class,
+                        () -> client().update(new UpdateRequest(INDEX, ID).doc(SOURCE)).actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+            {  // Testing NoOp Update
+                updateExpectedDocStatusCounter(client().index(new IndexRequest(INDEX).id(ID).source(SOURCE)).actionGet());
+
+                UpdateResponse response = client().update(new UpdateRequest(INDEX, ID).doc(SOURCE)).actionGet();
+                updateExpectedDocStatusCounter(response);
+
+                MatcherAssert.assertThat(response.getResult(), equalTo(DocWriteResponse.Result.NOOP));
+                assertDocStatusStats();
+            }
+            {  // Testing Update
+                final String UPDATED_VALUE = "updated_value";
+                UpdateResponse response = client().update(new UpdateRequest(INDEX, ID).doc(singletonMap(FIELD, UPDATED_VALUE))).actionGet();
+                updateExpectedDocStatusCounter(response);
+
+                MatcherAssert.assertThat(response.getResult(), equalTo(DocWriteResponse.Result.UPDATED));
+                assertDocStatusStats();
+            }
+            {  // Testing Missing Alias
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        IndexNotFoundException.class,
+                        () -> client().update(new UpdateRequest(INDEX, ID).setRequireAlias(true).doc(new IndexRequest().source(SOURCE)))
+                            .actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+            {  // Testing Version Conflict
+                final String docId = "version_conflict";
+
+                updateExpectedDocStatusCounter(client().index(new IndexRequest(INDEX).id(docId).source(SOURCE)).actionGet());
+                updateExpectedDocStatusCounter(
+                    expectThrows(
+                        VersionConflictEngineException.class,
+                        () -> client().update(new UpdateRequest(INDEX, docId).doc(SOURCE).setIfSeqNo(2L).setIfPrimaryTerm(99L)).actionGet()
+                    )
+                );
+                assertDocStatusStats();
+            }
+        }
+    }
+
+    private void assertDocStatusStats() {
+        DocStatusStats docStatusStats = client().admin()
+            .cluster()
+            .prepareNodesStats()
+            .execute()
+            .actionGet()
+            .getNodes()
+            .get(0)
+            .getIndices()
+            .getIndexing()
+            .getTotal()
+            .getDocStatusStats();
+
+        assertTrue(
+            Arrays.equals(
+                docStatusStats.getDocStatusCounter(),
+                expectedDocStatusStats.getDocStatusCounter(),
+                Comparator.comparingLong(AtomicLong::longValue)
+            )
+        );
+    }
+
+    private void updateExpectedDocStatusCounter(DocWriteResponse r) {
+        expectedDocStatusStats.inc(r.status());
+    }
+
+    private void updateExpectedDocStatusCounter(Exception e) {
+        expectedDocStatusStats.inc(ExceptionsHelper.status(e));
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/operateAllIndices/DestructiveOperationsIT.java b/server/src/internalClusterTest/java/org/opensearch/operateAllIndices/DestructiveOperationsIT.java
index 7a19f3c832312..4732456cb092e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/operateAllIndices/DestructiveOperationsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/operateAllIndices/DestructiveOperationsIT.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.operateAllIndices;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.support.DestructiveOperations;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -109,8 +108,8 @@ public void testCloseIndexDefaultBehaviour() throws Exception {
         }
 
         ClusterState state = client().admin().cluster().prepareState().get().getState();
-        for (ObjectObjectCursor<String, IndexMetadata> indexMetadataObjectObjectCursor : state.getMetadata().indices()) {
-            assertEquals(IndexMetadata.State.CLOSE, indexMetadataObjectObjectCursor.value.getState());
+        for (final IndexMetadata indexMetadataObjectObjectCursor : state.getMetadata().indices().values()) {
+            assertEquals(IndexMetadata.State.CLOSE, indexMetadataObjectObjectCursor.getState());
         }
     }
 
@@ -141,8 +140,8 @@ public void testOpenIndexDefaultBehaviour() throws Exception {
         }
 
         ClusterState state = client().admin().cluster().prepareState().get().getState();
-        for (ObjectObjectCursor<String, IndexMetadata> indexMetadataObjectObjectCursor : state.getMetadata().indices()) {
-            assertEquals(IndexMetadata.State.OPEN, indexMetadataObjectObjectCursor.value.getState());
+        for (final IndexMetadata indexMetadataObjectObjectCursor : state.getMetadata().indices().values()) {
+            assertEquals(IndexMetadata.State.OPEN, indexMetadataObjectObjectCursor.getState());
         }
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/persistent/PersistentTasksExecutorIT.java b/server/src/internalClusterTest/java/org/opensearch/persistent/PersistentTasksExecutorIT.java
index 9ea80ae7dbd89..312b98a8dd918 100644
--- a/server/src/internalClusterTest/java/org/opensearch/persistent/PersistentTasksExecutorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/persistent/PersistentTasksExecutorIT.java
@@ -38,6 +38,7 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.persistent.PersistentTasksService.WaitForPersistentTaskListener;
 import org.opensearch.persistent.TestPersistentTasksPlugin.State;
@@ -45,7 +46,6 @@
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestPersistentTasksExecutor;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestTasksRequestBuilder;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.junit.After;
@@ -224,7 +224,7 @@ public void testPersistentActionWithNoAvailableNode() throws Exception {
     public void testPersistentActionWithNonClusterStateCondition() throws Exception {
         PersistentTasksClusterService persistentTasksClusterService = internalCluster().getInstance(
             PersistentTasksClusterService.class,
-            internalCluster().getMasterName()
+            internalCluster().getClusterManagerName()
         );
         // Speed up rechecks to a rate that is quicker than what settings would allow
         persistentTasksClusterService.setRecheckInterval(TimeValue.timeValueMillis(1));
@@ -384,7 +384,7 @@ public void testCreatePersistentTaskWithDuplicateId() throws Exception {
     public void testUnassignRunningPersistentTask() throws Exception {
         PersistentTasksClusterService persistentTasksClusterService = internalCluster().getInstance(
             PersistentTasksClusterService.class,
-            internalCluster().getMasterName()
+            internalCluster().getClusterManagerName()
         );
         // Speed up rechecks to a rate that is quicker than what settings would allow
         persistentTasksClusterService.setRecheckInterval(TimeValue.timeValueMillis(1));
@@ -403,7 +403,7 @@ public void testUnassignRunningPersistentTask() throws Exception {
 
         PlainActionFuture<PersistentTask<?>> unassignmentFuture = new PlainActionFuture<>();
 
-        // Disallow re-assignment after it is unallocated to verify master and node state
+        // Disallow re-assignment after it is unallocated to verify cluster-manager and node state
         TestPersistentTasksExecutor.setNonClusterStateCondition(false);
 
         persistentTasksClusterService.unassignPersistentTask(taskId, task.getAllocationId() + 1, "unassignment test", unassignmentFuture);
diff --git a/server/src/internalClusterTest/java/org/opensearch/persistent/decider/EnableAssignmentDeciderIT.java b/server/src/internalClusterTest/java/org/opensearch/persistent/decider/EnableAssignmentDeciderIT.java
index 5d75482567731..a749ad54042ab 100644
--- a/server/src/internalClusterTest/java/org/opensearch/persistent/decider/EnableAssignmentDeciderIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/persistent/decider/EnableAssignmentDeciderIT.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.persistent.decider;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.persistent.PersistentTasksCustomMetadata;
 import org.opensearch.persistent.PersistentTasksService;
 import org.opensearch.persistent.TestPersistentTasksPlugin;
@@ -87,7 +87,7 @@ public void testEnableAssignmentAfterRestart() throws Exception {
         }
         latch.await();
 
-        ClusterService clusterService = internalCluster().clusterService(internalCluster().getMasterName());
+        ClusterService clusterService = internalCluster().clusterService(internalCluster().getClusterManagerName());
         PersistentTasksCustomMetadata tasks = clusterService.state().getMetadata().custom(PersistentTasksCustomMetadata.TYPE);
         assertEquals(numberOfTasks, tasks.tasks().stream().filter(t -> TestPersistentTasksExecutor.NAME.equals(t.getTaskName())).count());
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/recovery/FullRollingRestartIT.java b/server/src/internalClusterTest/java/org/opensearch/recovery/FullRollingRestartIT.java
index 15d1f3a0559a8..f636185fd4649 100644
--- a/server/src/internalClusterTest/java/org/opensearch/recovery/FullRollingRestartIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/recovery/FullRollingRestartIT.java
@@ -196,10 +196,10 @@ public void testFullRollingRestart() throws Exception {
 
     public void testNoRebalanceOnRollingRestart() throws Exception {
         // see https://github.com/elastic/elasticsearch/issues/14387
-        internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startClusterManagerOnlyNode(Settings.EMPTY);
         internalCluster().startDataOnlyNodes(3);
         /**
-         * We start 3 nodes and a dedicated master. Restart on of the data-nodes and ensure that we got no relocations.
+         * We start 3 nodes and a dedicated cluster-manager. Restart on of the data-nodes and ensure that we got no relocations.
          * Yet we have 6 shards 0 replica so that means if the restarting node comes back both other nodes are subject
          * to relocating to the restarting node since all had 2 shards and now one node has nothing allocated.
          * We have a fix for this to wait until we have allocated unallocated shards now so this shouldn't happen.
diff --git a/server/src/internalClusterTest/java/org/opensearch/recovery/RecoveryWhileUnderLoadIT.java b/server/src/internalClusterTest/java/org/opensearch/recovery/RecoveryWhileUnderLoadIT.java
index 26b3e9ae336dc..30d5af58df545 100644
--- a/server/src/internalClusterTest/java/org/opensearch/recovery/RecoveryWhileUnderLoadIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/recovery/RecoveryWhileUnderLoadIT.java
@@ -46,11 +46,11 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.DocsStats;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.sort.SortOrder;
diff --git a/server/src/internalClusterTest/java/org/opensearch/recovery/RelocationIT.java b/server/src/internalClusterTest/java/org/opensearch/recovery/RelocationIT.java
index 06475f1e7ac9d..1f0b4fdf370fe 100644
--- a/server/src/internalClusterTest/java/org/opensearch/recovery/RelocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/recovery/RelocationIT.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.recovery;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.tests.util.English;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteResponse;
 import org.opensearch.action.admin.indices.stats.ShardStats;
@@ -53,9 +51,11 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
@@ -65,18 +65,17 @@
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.indices.recovery.FileChunkRequest;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
-import org.opensearch.indices.recovery.RecoveryFileChunkRequest;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.test.BackgroundIndexer;
+import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.MockIndexEventListener;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalSettingsPlugin;
-import org.opensearch.test.MockIndexEventListener;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.test.transport.StubbableTransport;
 import org.opensearch.transport.Transport;
@@ -376,12 +375,12 @@ public void indexShardStateChanged(
 
             List<IndexRequestBuilder> builders1 = new ArrayList<>();
             for (int numDocs = randomIntBetween(10, 30); numDocs > 0; numDocs--) {
-                builders1.add(client().prepareIndex("test").setSource("{}", XContentType.JSON));
+                builders1.add(client().prepareIndex("test").setSource("{}", MediaTypeRegistry.JSON));
             }
 
             List<IndexRequestBuilder> builders2 = new ArrayList<>();
             for (int numDocs = randomIntBetween(10, 30); numDocs > 0; numDocs--) {
-                builders2.add(client().prepareIndex("test").setSource("{}", XContentType.JSON));
+                builders2.add(client().prepareIndex("test").setSource("{}", MediaTypeRegistry.JSON));
             }
 
             logger.info("--> START relocate the shard from {} to {}", nodes[fromNode], nodes[toNode]);
@@ -441,7 +440,7 @@ public void testCancellationCleansTempFiles() throws Exception {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName).setSource("{}", XContentType.JSON));
+            requests.add(client().prepareIndex(indexName).setSource("{}", MediaTypeRegistry.JSON));
         }
         indexRandom(true, requests);
         assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("3").setWaitForGreenStatus().get().isTimedOut());
@@ -771,8 +770,8 @@ public void testRelocationEstablishedPeerRecoveryRetentionLeases() throws Except
 
     private void assertActiveCopiesEstablishedPeerRecoveryRetentionLeases() throws Exception {
         assertBusy(() -> {
-            for (ObjectCursor<String> it : client().admin().cluster().prepareState().get().getState().metadata().indices().keys()) {
-                Map<ShardId, List<ShardStats>> byShardId = Stream.of(client().admin().indices().prepareStats(it.value).get().getShards())
+            for (final String it : client().admin().cluster().prepareState().get().getState().metadata().indices().keySet()) {
+                Map<ShardId, List<ShardStats>> byShardId = Stream.of(client().admin().indices().prepareStats(it).get().getShards())
                     .collect(Collectors.groupingBy(l -> l.getShardRouting().shardId()));
                 for (List<ShardStats> shardStats : byShardId.values()) {
                     Set<String> expectedLeaseIds = shardStats.stream()
@@ -809,7 +808,7 @@ public void sendRequest(
             TransportRequestOptions options
         ) throws IOException {
             if (action.equals(PeerRecoveryTargetService.Actions.FILE_CHUNK)) {
-                RecoveryFileChunkRequest chunkRequest = (RecoveryFileChunkRequest) request;
+                FileChunkRequest chunkRequest = (FileChunkRequest) request;
                 if (chunkRequest.name().startsWith(IndexFileNames.SEGMENTS)) {
                     // corrupting the segments_N files in order to make sure future recovery re-send files
                     logger.debug("corrupting [{}] to {}. file name: [{}]", action, connection.getNode(), chunkRequest.name());
diff --git a/server/src/internalClusterTest/java/org/opensearch/recovery/SimpleRecoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/recovery/SimpleRecoveryIT.java
index 4ebb840c600d2..85f90738b19ce 100644
--- a/server/src/internalClusterTest/java/org/opensearch/recovery/SimpleRecoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/recovery/SimpleRecoveryIT.java
@@ -36,7 +36,7 @@
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.opensearch.client.Requests.flushRequest;
@@ -44,7 +44,6 @@
 import static org.opensearch.client.Requests.indexRequest;
 import static org.opensearch.client.Requests.refreshRequest;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.equalTo;
 
 public class SimpleRecoveryIT extends OpenSearchIntegTestCase {
@@ -67,12 +66,12 @@ public void testSimpleRecovery() throws Exception {
 
         NumShards numShards = getNumShards("test");
 
-        client().index(indexRequest("test").id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
+        client().index(indexRequest("test").id("1").source(source("1", "test"), MediaTypeRegistry.JSON)).actionGet();
         FlushResponse flushResponse = client().admin().indices().flush(flushRequest("test")).actionGet();
         assertThat(flushResponse.getTotalShards(), equalTo(numShards.totalNumShards));
         assertThat(flushResponse.getSuccessfulShards(), equalTo(numShards.numPrimaries));
         assertThat(flushResponse.getFailedShards(), equalTo(0));
-        client().index(indexRequest("test").id("2").source(source("2", "test"), XContentType.JSON)).actionGet();
+        client().index(indexRequest("test").id("2").source(source("2", "test"), MediaTypeRegistry.JSON)).actionGet();
         RefreshResponse refreshResponse = client().admin().indices().refresh(refreshRequest("test")).actionGet();
         assertThat(refreshResponse.getTotalShards(), equalTo(numShards.totalNumShards));
         assertThat(refreshResponse.getSuccessfulShards(), equalTo(numShards.numPrimaries));
diff --git a/server/src/internalClusterTest/java/org/opensearch/recovery/TruncatedRecoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/recovery/TruncatedRecoveryIT.java
index 1708454faf7b3..5f0922615a557 100644
--- a/server/src/internalClusterTest/java/org/opensearch/recovery/TruncatedRecoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/recovery/TruncatedRecoveryIT.java
@@ -39,11 +39,11 @@
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.indices.recovery.FileChunkRequest;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
-import org.opensearch.indices.recovery.RecoveryFileChunkRequest;
 import org.opensearch.node.RecoverySettingsChunkSizePlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -146,7 +146,7 @@ public void testCancelRecoveryAndResume() throws Exception {
                 internalCluster().getInstance(TransportService.class, unluckyNode.getNode().getName()),
                 (connection, requestId, action, request, options) -> {
                     if (action.equals(PeerRecoveryTargetService.Actions.FILE_CHUNK)) {
-                        RecoveryFileChunkRequest req = (RecoveryFileChunkRequest) request;
+                        FileChunkRequest req = (FileChunkRequest) request;
                         logger.info("file chunk [{}] lastChunk: {}", req, req.lastChunk());
                         if ((req.name().endsWith("cfs") || req.name().endsWith("fdt")) && req.lastChunk() && truncate.get()) {
                             latch.countDown();
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/AbstractRemoteStoreMockRepositoryIntegTestCase.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/AbstractRemoteStoreMockRepositoryIntegTestCase.java
new file mode 100644
index 0000000000000..9d4d8aa24bd51
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/AbstractRemoteStoreMockRepositoryIntegTestCase.java
@@ -0,0 +1,185 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.snapshots.AbstractSnapshotIntegTestCase;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Locale;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+
+public abstract class AbstractRemoteStoreMockRepositoryIntegTestCase extends AbstractSnapshotIntegTestCase {
+
+    protected static final String REPOSITORY_NAME = "my-segment-repo-1";
+    protected static final String TRANSLOG_REPOSITORY_NAME = "my-translog-repo-1";
+    protected static final String INDEX_NAME = "remote-store-test-idx-1";
+
+    @Override
+    public Settings indexSettings() {
+        return remoteStoreIndexSettings(0);
+    }
+
+    protected Settings remoteStoreIndexSettings(int numberOfReplicas) {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "300s")
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numberOfReplicas)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    public Settings buildRemoteStoreNodeAttributes(Path repoLocation, double ioFailureRate, String skipExceptionBlobList, long maxFailure) {
+        String segmentRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            REPOSITORY_NAME
+        );
+        String translogRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            TRANSLOG_REPOSITORY_NAME
+        );
+        String segmentRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            REPOSITORY_NAME
+        );
+        String translogRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            TRANSLOG_REPOSITORY_NAME
+        );
+        String stateRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            REPOSITORY_NAME
+        );
+        String stateRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            REPOSITORY_NAME
+        );
+
+        return Settings.builder()
+            .put("node.attr." + REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, REPOSITORY_NAME)
+            .put(segmentRepoTypeAttributeKey, "mock")
+            .put(segmentRepoSettingsAttributeKeyPrefix + "location", repoLocation)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "random_control_io_exception_rate", ioFailureRate)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "skip_exception_on_verification_file", true)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "skip_exception_on_list_blobs", true)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "skip_exception_on_blobs", skipExceptionBlobList)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "max_failure_number", maxFailure)
+            .put("node.attr." + REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, TRANSLOG_REPOSITORY_NAME)
+            .put(translogRepoTypeAttributeKey, "mock")
+            .put(translogRepoSettingsAttributeKeyPrefix + "location", repoLocation)
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, REPOSITORY_NAME)
+            .put(stateRepoTypeAttributeKey, "mock")
+            .put(stateRepoSettingsAttributeKeyPrefix + "location", repoLocation)
+            .build();
+    }
+
+    protected void cleanupRepo() {
+        logger.info("--> Cleanup the repository={}", REPOSITORY_NAME);
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_NAME).execute().actionGet();
+        logger.info("--> Cleanup the repository={}", TRANSLOG_REPOSITORY_NAME);
+        clusterAdmin().prepareCleanupRepository(TRANSLOG_REPOSITORY_NAME).execute().actionGet();
+    }
+
+    protected String setup(Path repoLocation, double ioFailureRate, String skipExceptionBlobList, long maxFailure) {
+        // The random_control_io_exception_rate setting ensures that 10-25% of all operations to remote store results in
+        /// IOException. skip_exception_on_verification_file & skip_exception_on_list_blobs settings ensures that the
+        // repository creation can happen without failure.
+        Settings.Builder settings = Settings.builder()
+            .put(buildRemoteStoreNodeAttributes(repoLocation, ioFailureRate, skipExceptionBlobList, maxFailure));
+
+        if (randomBoolean()) {
+            settings.put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT);
+        }
+
+        disableRepoConsistencyCheck("Remote Store Creates System Repository");
+
+        internalCluster().startClusterManagerOnlyNode(settings.build());
+        String dataNodeName = internalCluster().startDataOnlyNode(settings.build());
+        createIndex(INDEX_NAME);
+        logger.info("--> Created index={}", INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        logger.info("--> Cluster is yellow with no initializing shards");
+        ensureGreen(INDEX_NAME);
+        logger.info("--> Cluster is green");
+        return dataNodeName;
+    }
+
+    /**
+     * Gets all segment files which starts with "_". For instance, _0.cfe, _o.cfs etc.
+     *
+     * @param location the path to location where segment files are being searched.
+     * @return set of file names of all segment file or empty set if there was IOException thrown.
+     */
+    protected Set<String> getSegmentFiles(Path location) {
+        try {
+            return Arrays.stream(FileSystemUtils.files(location))
+                .filter(path -> path.getFileName().toString().startsWith("_"))
+                .map(path -> path.getFileName().toString())
+                .map(this::getLocalSegmentFilename)
+                .collect(Collectors.toSet());
+        } catch (IOException exception) {
+            logger.error("Exception occurred while getting segment files", exception);
+        }
+        return Collections.emptySet();
+    }
+
+    private String getLocalSegmentFilename(String remoteFilename) {
+        return remoteFilename.split(RemoteSegmentStoreDirectory.SEGMENT_NAME_UUID_SEPARATOR)[0];
+    }
+
+    private IndexResponse indexSingleDoc() {
+        return client().prepareIndex(INDEX_NAME)
+            .setId(UUIDs.randomBase64UUID())
+            .setSource(randomAlphaOfLength(5), randomAlphaOfLength(5))
+            .get();
+    }
+
+    protected void indexData(int numberOfIterations, boolean invokeFlush) {
+        logger.info("--> Indexing data for {} iterations with flush={}", numberOfIterations, invokeFlush);
+        for (int i = 0; i < numberOfIterations; i++) {
+            int numberOfOperations = randomIntBetween(1, 5);
+            logger.info("--> Indexing {} operations in iteration #{}", numberOfOperations, i);
+            for (int j = 0; j < numberOfOperations; j++) {
+                indexSingleDoc();
+            }
+            if (invokeFlush) {
+                flush(INDEX_NAME);
+            } else {
+                refresh(INDEX_NAME);
+            }
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/BaseRemoteStoreRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/BaseRemoteStoreRestoreIT.java
new file mode 100644
index 0000000000000..ad3e99dd274ce
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/BaseRemoteStoreRestoreIT.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+public class BaseRemoteStoreRestoreIT extends RemoteStoreBaseIntegTestCase {
+    static final String INDEX_NAME = "remote-store-test-idx-1";
+    static final String INDEX_NAMES = "test-remote-store-1,test-remote-store-2,remote-store-test-index-1,remote-store-test-index-2";
+    static final String INDEX_NAMES_WILDCARD = "test-remote-store-*,remote-store-test-index-*";
+    static final String TOTAL_OPERATIONS = "total-operations";
+    static final String REFRESHED_OR_FLUSHED_OPERATIONS = "refreshed-or-flushed-operations";
+    static final String MAX_SEQ_NO_TOTAL = "max-seq-no-total";
+
+    @Override
+    public Settings indexSettings() {
+        return remoteStoreIndexSettings(0);
+    }
+
+    public Settings indexSettings(int shards, int replicas) {
+        return remoteStoreIndexSettings(replicas, shards);
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class);
+    }
+
+    protected void restore(String... indices) {
+        boolean restoreAllShards = randomBoolean();
+        if (restoreAllShards) {
+            assertAcked(client().admin().indices().prepareClose(indices));
+        }
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(indices).restoreAllShards(restoreAllShards),
+                PlainActionFuture.newFuture()
+            );
+    }
+
+    protected void verifyRestoredData(Map<String, Long> indexStats, String indexName) throws Exception {
+        ensureYellowAndNoInitializingShards(indexName);
+        ensureGreen(indexName);
+        // This is to ensure that shards that were already assigned will get latest count
+        refresh(indexName);
+        assertBusy(
+            () -> assertHitCount(client().prepareSearch(indexName).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS)),
+            30,
+            TimeUnit.SECONDS
+        );
+        IndexResponse response = indexSingleDoc(indexName);
+        if (indexStats.containsKey(MAX_SEQ_NO_TOTAL + "-shard-" + response.getShardId().id())) {
+            assertEquals(indexStats.get(MAX_SEQ_NO_TOTAL + "-shard-" + response.getShardId().id()) + 1, response.getSeqNo());
+        }
+        refresh(indexName);
+        assertBusy(
+            () -> assertHitCount(client().prepareSearch(indexName).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS) + 1),
+            30,
+            TimeUnit.SECONDS
+        );
+    }
+
+    public void prepareCluster(int numClusterManagerNodes, int numDataOnlyNodes, String indices, int replicaCount, int shardCount) {
+        prepareCluster(numClusterManagerNodes, numDataOnlyNodes, indices, replicaCount, shardCount, Settings.EMPTY);
+    }
+
+    public void prepareCluster(
+        int numClusterManagerNodes,
+        int numDataOnlyNodes,
+        String indices,
+        int replicaCount,
+        int shardCount,
+        Settings settings
+    ) {
+        prepareCluster(numClusterManagerNodes, numDataOnlyNodes, settings);
+        for (String index : indices.split(",")) {
+            createIndex(index, remoteStoreIndexSettings(replicaCount, shardCount));
+            ensureYellowAndNoInitializingShards(index);
+            ensureGreen(index);
+        }
+    }
+
+    public void prepareCluster(int numClusterManagerNodes, int numDataOnlyNodes, Settings settings) {
+        internalCluster().startClusterManagerOnlyNodes(numClusterManagerNodes, settings);
+        internalCluster().startDataOnlyNodes(numDataOnlyNodes, settings);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexClusterDefaultDocRepIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexClusterDefaultDocRepIT.java
new file mode 100644
index 0000000000000..e1ab101fddf55
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexClusterDefaultDocRepIT.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.indices.get.GetIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Locale;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.containsString;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
+public class CreateRemoteIndexClusterDefaultDocRepIT extends CreateRemoteIndexIT {
+
+    @Override
+    protected Settings nodeSettings(int nodeOriginal) {
+        Settings settings = super.nodeSettings(nodeOriginal);
+        Settings.Builder builder = Settings.builder()
+            .put(settings)
+            .put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.DOCUMENT);
+        return builder.build();
+    }
+
+    @Override
+    public void testDefaultRemoteStoreNoUserOverride() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .build();
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "To enable %s, %s should be set to %s",
+                    SETTING_REMOTE_STORE_ENABLED,
+                    SETTING_REPLICATION_TYPE,
+                    ReplicationType.SEGMENT
+                )
+            )
+        );
+    }
+
+    public void testDefaultRemoteStoreNoUserOverrideExceptReplicationTypeSegment() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        assertAcked(client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get());
+        GetIndexResponse getIndexResponse = client().admin()
+            .indices()
+            .getIndex(new GetIndexRequest().indices("test-idx-1").includeDefaults(true))
+            .get();
+        Settings indexSettings = getIndexResponse.settings().get("test-idx-1");
+        verifyRemoteStoreIndexSettings(
+            indexSettings,
+            "true",
+            REPOSITORY_NAME,
+            REPOSITORY_2_NAME,
+            ReplicationType.SEGMENT.toString(),
+            IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
+        );
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexIT.java
new file mode 100644
index 0000000000000..d427a4db84ba2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/CreateRemoteIndexIT.java
@@ -0,0 +1,262 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.indices.get.GetIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.util.Locale;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.index.IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.containsString;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
+public class CreateRemoteIndexIT extends RemoteStoreBaseIntegTestCase {
+
+    @Before
+    public void setup() throws Exception {
+        internalCluster().startNodes(2);
+    }
+
+    public void testDefaultRemoteStoreNoUserOverride() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .build();
+        assertAcked(client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get());
+        GetIndexResponse getIndexResponse = client().admin()
+            .indices()
+            .getIndex(new GetIndexRequest().indices("test-idx-1").includeDefaults(true))
+            .get();
+        Settings indexSettings = getIndexResponse.settings().get("test-idx-1");
+        verifyRemoteStoreIndexSettings(
+            indexSettings,
+            "true",
+            REPOSITORY_NAME,
+            REPOSITORY_2_NAME,
+            ReplicationType.SEGMENT.toString(),
+            IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
+        );
+    }
+
+    public void testRemoteStoreDisabledByUser() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REMOTE_STORE_ENABLED, false)
+            .build();
+
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Validation Failed: 1: private index setting [%s] can not be set explicitly;",
+                    SETTING_REMOTE_STORE_ENABLED
+                )
+            )
+        );
+    }
+
+    public void testRemoteStoreEnabledByUserWithoutRemoteRepoAndSegmentReplicationIllegalArgumentException() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REMOTE_STORE_ENABLED, true)
+            .build();
+
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString("To enable index.remote_store.enabled, index.replication.type should be set to SEGMENT")
+        );
+    }
+
+    public void testRemoteStoreEnabledByUserWithoutRemoteRepoIllegalArgumentException() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SETTING_REMOTE_STORE_ENABLED, true)
+            .build();
+
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Validation Failed: 1: private index setting [%s] can not be set explicitly;",
+                    SETTING_REMOTE_STORE_ENABLED
+                )
+            )
+        );
+    }
+
+    public void testReplicationTypeDocumentByUser() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+            .build();
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "To enable %s, %s should be set to %s",
+                    SETTING_REMOTE_STORE_ENABLED,
+                    SETTING_REPLICATION_TYPE,
+                    ReplicationType.SEGMENT
+                )
+            )
+        );
+    }
+
+    public void testRemoteStoreSegmentRepoWithoutRemoteEnabledAndSegmentReplicationIllegalArgumentException() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-custom-repo")
+            .build();
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Settings %s can only be set/enabled when %s is set to true",
+                    SETTING_REMOTE_SEGMENT_STORE_REPOSITORY,
+                    SETTING_REMOTE_STORE_ENABLED
+                )
+            )
+        );
+    }
+
+    public void testRemoteStoreEnabledByUserWithRemoteRepoIllegalArgumentException() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SETTING_REMOTE_STORE_ENABLED, true)
+            .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-custom-repo")
+            .build();
+
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Validation Failed: 1: private index setting [%s] can not be set explicitly;2: private index setting [%s] can not be set explicitly;",
+                    SETTING_REMOTE_STORE_ENABLED,
+                    SETTING_REMOTE_SEGMENT_STORE_REPOSITORY
+                )
+            )
+        );
+    }
+
+    public void testRemoteStoreOverrideOnlyTranslogRepoIllegalArgumentException() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "my-custom-repo")
+            .build();
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Settings %s can only be set/enabled when %s is set to true",
+                    SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY,
+                    SETTING_REMOTE_STORE_ENABLED
+                )
+            )
+        );
+    }
+
+    public void testRemoteStoreOverrideTranslogRepoCorrectly() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SETTING_REMOTE_STORE_ENABLED, true)
+            .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-custom-repo")
+            .put(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "my-custom-repo")
+            .build();
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin().indices().prepareCreate("test-idx-1").setSettings(settings).get()
+        );
+        assertThat(
+            exc.getMessage(),
+            containsString(
+                String.format(
+                    Locale.ROOT,
+                    "Validation Failed: 1: private index setting [%s] can not be set explicitly;2: private index setting [%s] can not be set explicitly;3: private index setting [%s] can not be set explicitly;",
+                    SETTING_REMOTE_STORE_ENABLED,
+                    SETTING_REMOTE_SEGMENT_STORE_REPOSITORY,
+                    SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY
+                )
+            )
+        );
+    }
+
+    protected void verifyRemoteStoreIndexSettings(
+        Settings indexSettings,
+        String isRemoteSegmentEnabled,
+        String remoteSegmentRepo,
+        String remoteTranslogRepo,
+        String replicationType,
+        TimeValue translogBufferInterval
+    ) {
+        assertEquals(replicationType, indexSettings.get(SETTING_REPLICATION_TYPE));
+        assertEquals(isRemoteSegmentEnabled, indexSettings.get(SETTING_REMOTE_STORE_ENABLED));
+        assertEquals(remoteSegmentRepo, indexSettings.get(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY));
+        assertEquals(remoteTranslogRepo, indexSettings.get(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY));
+        assertEquals(translogBufferInterval, INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(indexSettings));
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/PrimaryTermValidationIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/PrimaryTermValidationIT.java
new file mode 100644
index 0000000000000..e14a4062f7775
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/PrimaryTermValidationIT.java
@@ -0,0 +1,170 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
+import org.opensearch.action.admin.indices.refresh.RefreshResponse;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.coordination.FollowersChecker;
+import org.opensearch.cluster.coordination.LeaderChecker;
+import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.cluster.health.ClusterIndexHealth;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.shard.ShardNotFoundException;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+import org.junit.Before;
+
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
+import static org.hamcrest.Matchers.equalTo;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class PrimaryTermValidationIT extends RemoteStoreBaseIntegTestCase {
+
+    private static final String INDEX_NAME = "remote-store-test-idx-1";
+    protected Path absolutePath;
+    protected Path absolutePath2;
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class);
+    }
+
+    @Before
+    public void setup() {
+        absolutePath = randomRepoPath().toAbsolutePath();
+        absolutePath2 = randomRepoPath().toAbsolutePath();
+    }
+
+    public void testPrimaryTermValidation() throws Exception {
+        // Follower checker interval is lower compared to leader checker so that the cluster manager can remove the node
+        // with network partition faster. The follower check retry count is also kept 1.
+        Settings clusterSettings = Settings.builder()
+            .put(LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
+            .put(LeaderChecker.LEADER_CHECK_INTERVAL_SETTING.getKey(), "20s")
+            .put(LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING.getKey(), 4)
+            .put(FollowersChecker.FOLLOWER_CHECK_TIMEOUT_SETTING.getKey(), "1s")
+            .put(FollowersChecker.FOLLOWER_CHECK_INTERVAL_SETTING.getKey(), "1s")
+            .put(FollowersChecker.FOLLOWER_CHECK_RETRY_COUNT_SETTING.getKey(), 1)
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, absolutePath, REPOSITORY_2_NAME, absolutePath2))
+            .build();
+        internalCluster().startClusterManagerOnlyNode(clusterSettings);
+        internalCluster().startDataOnlyNodes(2, clusterSettings);
+
+        // Create index
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        // Get the names of nodes to create network disruption
+        String primaryNode = primaryNodeName(INDEX_NAME);
+        String replicaNode = replicaNodeName(INDEX_NAME);
+        String clusterManagerNode = internalCluster().getClusterManagerName();
+        logger.info("Node names : clusterManager={} primary={} replica={}", clusterManagerNode, primaryNode, replicaNode);
+
+        // Index some docs and validate that both primary and replica node has it. Refresh is triggered to trigger segment replication
+        // to ensure replica is also upto date.
+        int numOfDocs = randomIntBetween(5, 10);
+        for (int i = 0; i < numOfDocs; i++) {
+            indexSameDoc(clusterManagerNode, INDEX_NAME);
+        }
+        refresh(INDEX_NAME);
+        assertBusy(
+            () -> assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), numOfDocs)
+        );
+        assertBusy(
+            () -> assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), numOfDocs)
+        );
+
+        // Start network disruption - primary node will be isolated
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode, replicaNode).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(primaryNode).collect(Collectors.toCollection(HashSet::new));
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        // Ensure the node which is partitioned is removed from the cluster
+        assertBusy(() -> {
+            NodesInfoResponse response = client(clusterManagerNode).admin().cluster().prepareNodesInfo().get();
+            assertThat(response.getNodes().size(), equalTo(2));
+        });
+
+        // Ensure that the cluster manager has latest information about the index
+        assertBusy(() -> {
+            ClusterHealthResponse clusterHealthResponse = client(clusterManagerNode).admin()
+                .cluster()
+                .health(new ClusterHealthRequest())
+                .actionGet(TimeValue.timeValueSeconds(1));
+            assertTrue(clusterHealthResponse.getIndices().containsKey(INDEX_NAME));
+            ClusterIndexHealth clusterIndexHealth = clusterHealthResponse.getIndices().get(INDEX_NAME);
+            assertEquals(ClusterHealthStatus.YELLOW, clusterHealthResponse.getStatus());
+            assertEquals(1, clusterIndexHealth.getNumberOfShards());
+            assertEquals(1, clusterIndexHealth.getActiveShards());
+            assertEquals(1, clusterIndexHealth.getUnassignedShards());
+            assertEquals(1, clusterIndexHealth.getUnassignedShards());
+            assertEquals(1, clusterIndexHealth.getActivePrimaryShards());
+            assertEquals(ClusterHealthStatus.YELLOW, clusterIndexHealth.getStatus());
+        });
+
+        // Index data to the newly promoted primary
+        indexSameDoc(clusterManagerNode, INDEX_NAME);
+        RefreshResponse refreshResponse = client(clusterManagerNode).admin()
+            .indices()
+            .prepareRefresh(INDEX_NAME)
+            .setIndicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_HIDDEN_FORBID_CLOSED)
+            .execute()
+            .actionGet();
+        assertNoFailures(refreshResponse);
+        assertEquals(1, refreshResponse.getSuccessfulShards());
+        assertHitCount(client(replicaNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), numOfDocs + 1);
+
+        // At this point we stop the disruption. Since the follower checker has already failed and cluster manager has removed the node
+        // from cluster, failed node needs to start discovery process by leader checker call. We stop the disruption to allow the failed
+        // node to
+        // communicate with the other node which it assumes has replica.
+        networkDisruption.stopDisrupting();
+
+        // When the index call is made to the stale primary, it makes the primary term validation call to the other node (which
+        // it assumes has the replica node). At this moment, the stale primary realises that it is no more the primary and the caller
+        // received the following exception.
+        ShardNotFoundException exception = assertThrows(ShardNotFoundException.class, () -> indexSameDoc(primaryNode, INDEX_NAME));
+        assertTrue(exception.getMessage().contains("no such shard"));
+        internalCluster().clearDisruptionScheme();
+        ensureStableCluster(3);
+        ensureGreen(INDEX_NAME);
+    }
+
+    private IndexResponse indexSameDoc(String nodeName, String indexName) {
+        return client(nodeName).prepareIndex(indexName)
+            .setId(UUIDs.randomBase64UUID())
+            .setSource("{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON)
+            .get();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexPrimaryRelocationIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexPrimaryRelocationIT.java
new file mode 100644
index 0000000000000..d8b7718a55377
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexPrimaryRelocationIT.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.indices.recovery.IndexPrimaryRelocationIT;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteIndexPrimaryRelocationIT extends IndexPrimaryRelocationIT {
+
+    protected static final String REPOSITORY_NAME = "test-remote-store-repo";
+
+    protected Path absolutePath;
+
+    protected Settings nodeSettings(int nodeOrdinal) {
+        if (absolutePath == null) {
+            absolutePath = randomRepoPath().toAbsolutePath();
+        }
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, absolutePath))
+            .build();
+    }
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    public Settings indexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .build();
+    }
+
+    public void testPrimaryRelocationWhileIndexing() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        super.testPrimaryRelocationWhileIndexing();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexRecoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexRecoveryIT.java
new file mode 100644
index 0000000000000..c957f1b338bfe
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteIndexRecoveryIT.java
@@ -0,0 +1,166 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.recovery.IndexRecoveryIT;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.hamcrest.Matcher;
+import org.hamcrest.Matchers;
+import org.junit.After;
+import org.junit.Before;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteIndexRecoveryIT extends IndexRecoveryIT {
+
+    protected static final String REPOSITORY_NAME = "test-remote-store-repo";
+
+    protected Path repositoryPath;
+
+    @Before
+    public void setup() {
+        repositoryPath = randomRepoPath().toAbsolutePath();
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, repositoryPath))
+            .build();
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "300s")
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    @After
+    public void teardown() {
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_NAME).get();
+    }
+
+    @Override
+    protected Matcher<Long> getMatcherForThrottling(long value) {
+        return Matchers.greaterThanOrEqualTo(value);
+    }
+
+    @Override
+    protected int numDocs() {
+        return randomIntBetween(100, 200);
+    }
+
+    @Override
+    public void testUsesFileBasedRecoveryIfRetentionLeaseMissing() {
+        // Retention lease based tests not applicable for remote store;
+    }
+
+    @Override
+    public void testPeerRecoveryTrimsLocalTranslog() {
+        // Peer recovery usecase not valid for remote enabled indices
+    }
+
+    @Override
+    public void testHistoryRetention() {
+        // History retention not applicable for remote store
+    }
+
+    @Override
+    public void testUsesFileBasedRecoveryIfOperationsBasedRecoveryWouldBeUnreasonable() {
+        // History retention not applicable for remote store
+    }
+
+    @Override
+    public void testUsesFileBasedRecoveryIfRetentionLeaseAheadOfGlobalCheckpoint() {
+        // History retention not applicable for remote store
+    }
+
+    @Override
+    public void testRecoverLocallyUpToGlobalCheckpoint() {
+        // History retention not applicable for remote store
+    }
+
+    @Override
+    public void testCancelNewShardRecoveryAndUsesExistingShardCopy() {
+        // History retention not applicable for remote store
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testReservesBytesDuringPeerRecoveryPhaseOne() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testAllocateEmptyPrimaryResetsGlobalCheckpoint() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testDoesNotCopyOperationsInSafeCommit() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testRepeatedRecovery() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testDisconnectsWhileRecovering() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testTransientErrorsDuringRecoveryAreRetried() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testDoNotInfinitelyWaitForMapping() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testDisconnectsDuringRecovery() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8919")
+    @Override
+    public void testReplicaRecovery() {
+
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9580")
+    public void testRerouteRecovery() {
+
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteRestoreSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteRestoreSnapshotIT.java
new file mode 100644
index 0000000000000..4d3f0481e1e6f
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteRestoreSnapshotIT.java
@@ -0,0 +1,515 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.DocWriteResponse;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
+import org.opensearch.action.admin.indices.get.GetIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexResponse;
+import org.opensearch.action.delete.DeleteResponse;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.client.Client;
+import org.opensearch.client.Requests;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.snapshots.AbstractSnapshotIntegTestCase;
+import org.opensearch.snapshots.SnapshotState;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteRestoreSnapshotIT extends AbstractSnapshotIntegTestCase {
+    private static final String BASE_REMOTE_REPO = "test-rs-repo" + TEST_REMOTE_STORE_REPO_SUFFIX;
+    private Path remoteRepoPath;
+
+    @Before
+    public void setup() {
+        remoteRepoPath = randomRepoPath().toAbsolutePath();
+    }
+
+    @After
+    public void teardown() {
+        clusterAdmin().prepareCleanupRepository(BASE_REMOTE_REPO).get();
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(BASE_REMOTE_REPO, remoteRepoPath))
+            .build();
+    }
+
+    private Settings.Builder getIndexSettings(int numOfShards, int numOfReplicas) {
+        Settings.Builder settingsBuilder = Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numOfReplicas)
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "300s");
+        return settingsBuilder;
+    }
+
+    private void indexDocuments(Client client, String indexName, int numOfDocs) {
+        indexDocuments(client, indexName, 0, numOfDocs);
+    }
+
+    private void indexDocuments(Client client, String indexName, int fromId, int toId) {
+        for (int i = fromId; i < toId; i++) {
+            String id = Integer.toString(i);
+            client.prepareIndex(indexName).setId(id).setSource("text", "sometext").get();
+        }
+        client.admin().indices().prepareFlush(indexName).get();
+    }
+
+    private void assertDocsPresentInIndex(Client client, String indexName, int numOfDocs) {
+        for (int i = 0; i < numOfDocs; i++) {
+            String id = Integer.toString(i);
+            logger.info("checking for index " + indexName + " with docId" + id);
+            assertTrue("doc with id" + id + " is not present for index " + indexName, client.prepareGet(indexName, id).get().isExists());
+        }
+    }
+
+    public void testRestoreOperationsShallowCopyEnabled() throws IOException, ExecutionException, InterruptedException {
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        String primary = internalCluster().startDataOnlyNode();
+        String indexName1 = "testindex1";
+        String indexName2 = "testindex2";
+        String snapshotRepoName = "test-restore-snapshot-repo";
+        String snapshotName1 = "test-restore-snapshot1";
+        String snapshotName2 = "test-restore-snapshot2";
+        Path absolutePath1 = randomRepoPath().toAbsolutePath();
+        logger.info("Snapshot Path [{}]", absolutePath1);
+        String restoredIndexName1 = indexName1 + "-restored";
+        String restoredIndexName1Seg = indexName1 + "-restored-seg";
+        String restoredIndexName1Doc = indexName1 + "-restored-doc";
+        String restoredIndexName2 = indexName2 + "-restored";
+
+        createRepository(snapshotRepoName, "fs", getRepositorySettings(absolutePath1, true));
+
+        Client client = client();
+        Settings indexSettings = getIndexSettings(1, 0).build();
+        createIndex(indexName1, indexSettings);
+
+        Settings indexSettings2 = getIndexSettings(1, 0).build();
+        createIndex(indexName2, indexSettings2);
+
+        final int numDocsInIndex1 = 5;
+        final int numDocsInIndex2 = 6;
+        indexDocuments(client, indexName1, numDocsInIndex1);
+        indexDocuments(client, indexName2, numDocsInIndex2);
+        ensureGreen(indexName1, indexName2);
+
+        internalCluster().startDataOnlyNode();
+        logger.info("--> snapshot");
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1, indexName2)
+            .get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        updateRepository(snapshotRepoName, "fs", getRepositorySettings(absolutePath1, false));
+        CreateSnapshotResponse createSnapshotResponse2 = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName2)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1, indexName2)
+            .get();
+        assertThat(createSnapshotResponse2.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse2.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse2.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse2.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        DeleteResponse deleteResponse = client().prepareDelete(indexName1, "0").execute().actionGet();
+        assertEquals(deleteResponse.getResult(), DocWriteResponse.Result.DELETED);
+        indexDocuments(client, indexName1, numDocsInIndex1, numDocsInIndex1 + randomIntBetween(2, 5));
+        ensureGreen(indexName1);
+
+        RestoreSnapshotResponse restoreSnapshotResponse1 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(false)
+            .setIndices(indexName1)
+            .setRenamePattern(indexName1)
+            .setRenameReplacement(restoredIndexName1)
+            .get();
+        RestoreSnapshotResponse restoreSnapshotResponse2 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName2)
+            .setWaitForCompletion(false)
+            .setIndices(indexName2)
+            .setRenamePattern(indexName2)
+            .setRenameReplacement(restoredIndexName2)
+            .get();
+        assertEquals(restoreSnapshotResponse1.status(), RestStatus.ACCEPTED);
+        assertEquals(restoreSnapshotResponse2.status(), RestStatus.ACCEPTED);
+        ensureGreen(restoredIndexName1, restoredIndexName2);
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1);
+        assertDocsPresentInIndex(client, restoredIndexName2, numDocsInIndex2);
+
+        // deleting data for restoredIndexName1 and restoring from remote store.
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primary));
+        ensureRed(restoredIndexName1);
+        // Re-initialize client to make sure we are not using client from stopped node.
+        client = client(clusterManagerNode);
+        assertAcked(client.admin().indices().prepareClose(restoredIndexName1));
+        client.admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(restoredIndexName1).restoreAllShards(true),
+                PlainActionFuture.newFuture()
+            );
+        ensureYellowAndNoInitializingShards(restoredIndexName1);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client(), restoredIndexName1, numDocsInIndex1);
+        // indexing some new docs and validating
+        indexDocuments(client, restoredIndexName1, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1 + 2);
+
+        // restore index as seg rep enabled with remote store and remote translog disabled
+        RestoreSnapshotResponse restoreSnapshotResponse3 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(false)
+            .setIgnoreIndexSettings(IndexMetadata.SETTING_REMOTE_STORE_ENABLED)
+            .setIndices(indexName1)
+            .setRenamePattern(indexName1)
+            .setRenameReplacement(restoredIndexName1Seg)
+            .get();
+        assertEquals(restoreSnapshotResponse3.status(), RestStatus.ACCEPTED);
+        ensureGreen(restoredIndexName1Seg);
+
+        GetIndexResponse getIndexResponse = client.admin()
+            .indices()
+            .getIndex(new GetIndexRequest().indices(restoredIndexName1Seg).includeDefaults(true))
+            .get();
+        indexSettings = getIndexResponse.settings().get(restoredIndexName1Seg);
+        assertNull(indexSettings.get(SETTING_REMOTE_STORE_ENABLED));
+        assertNull(indexSettings.get(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, null));
+        assertEquals(ReplicationType.SEGMENT.toString(), indexSettings.get(IndexMetadata.SETTING_REPLICATION_TYPE));
+        assertDocsPresentInIndex(client, restoredIndexName1Seg, numDocsInIndex1);
+        // indexing some new docs and validating
+        indexDocuments(client, restoredIndexName1Seg, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(restoredIndexName1Seg);
+        assertDocsPresentInIndex(client, restoredIndexName1Seg, numDocsInIndex1 + 2);
+
+        // restore index as doc rep based from shallow copy snapshot
+        RestoreSnapshotResponse restoreSnapshotResponse4 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(false)
+            .setIgnoreIndexSettings(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, IndexMetadata.SETTING_REPLICATION_TYPE)
+            .setIndices(indexName1)
+            .setRenamePattern(indexName1)
+            .setRenameReplacement(restoredIndexName1Doc)
+            .get();
+        assertEquals(restoreSnapshotResponse4.status(), RestStatus.ACCEPTED);
+        ensureGreen(restoredIndexName1Doc);
+
+        getIndexResponse = client.admin()
+            .indices()
+            .getIndex(new GetIndexRequest().indices(restoredIndexName1Doc).includeDefaults(true))
+            .get();
+        indexSettings = getIndexResponse.settings().get(restoredIndexName1Doc);
+        assertNull(indexSettings.get(SETTING_REMOTE_STORE_ENABLED));
+        assertNull(indexSettings.get(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, null));
+        assertNull(indexSettings.get(IndexMetadata.SETTING_REPLICATION_TYPE));
+        assertDocsPresentInIndex(client, restoredIndexName1Doc, numDocsInIndex1);
+        // indexing some new docs and validating
+        indexDocuments(client, restoredIndexName1Doc, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(restoredIndexName1Doc);
+        assertDocsPresentInIndex(client, restoredIndexName1Doc, numDocsInIndex1 + 2);
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9326")
+    public void testRestoreInSameRemoteStoreEnabledIndex() throws IOException {
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        String primary = internalCluster().startDataOnlyNode();
+        String indexName1 = "testindex1";
+        String indexName2 = "testindex2";
+        String snapshotRepoName = "test-restore-snapshot-repo";
+        String snapshotName1 = "test-restore-snapshot1";
+        String snapshotName2 = "test-restore-snapshot2";
+        Path absolutePath1 = randomRepoPath().toAbsolutePath();
+        logger.info("Snapshot Path [{}]", absolutePath1);
+        String restoredIndexName2 = indexName2 + "-restored";
+
+        boolean enableShallowCopy = randomBoolean();
+        createRepository(snapshotRepoName, "fs", getRepositorySettings(absolutePath1, enableShallowCopy));
+
+        Client client = client();
+        Settings indexSettings = getIndexSettings(1, 0).build();
+        createIndex(indexName1, indexSettings);
+
+        Settings indexSettings2 = getIndexSettings(1, 0).build();
+        createIndex(indexName2, indexSettings2);
+
+        final int numDocsInIndex1 = 5;
+        final int numDocsInIndex2 = 6;
+        indexDocuments(client, indexName1, numDocsInIndex1);
+        indexDocuments(client, indexName2, numDocsInIndex2);
+        ensureGreen(indexName1, indexName2);
+
+        internalCluster().startDataOnlyNode();
+        logger.info("--> snapshot");
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1, indexName2)
+            .get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        updateRepository(snapshotRepoName, "fs", getRepositorySettings(absolutePath1, false));
+        CreateSnapshotResponse createSnapshotResponse2 = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName2)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1, indexName2)
+            .get();
+        assertThat(createSnapshotResponse2.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse2.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse2.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse2.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        DeleteResponse deleteResponse = client().prepareDelete(indexName1, "0").execute().actionGet();
+        assertEquals(deleteResponse.getResult(), DocWriteResponse.Result.DELETED);
+        indexDocuments(client, indexName1, numDocsInIndex1, numDocsInIndex1 + randomIntBetween(2, 5));
+        ensureGreen(indexName1);
+
+        assertAcked(client().admin().indices().prepareClose(indexName1));
+
+        RestoreSnapshotResponse restoreSnapshotResponse1 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(false)
+            .setIndices(indexName1)
+            .get();
+        RestoreSnapshotResponse restoreSnapshotResponse2 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName2)
+            .setWaitForCompletion(false)
+            .setIndices(indexName2)
+            .setRenamePattern(indexName2)
+            .setRenameReplacement(restoredIndexName2)
+            .get();
+        assertEquals(restoreSnapshotResponse1.status(), RestStatus.ACCEPTED);
+        assertEquals(restoreSnapshotResponse2.status(), RestStatus.ACCEPTED);
+        ensureGreen(indexName1, restoredIndexName2);
+        assertDocsPresentInIndex(client, indexName1, numDocsInIndex1);
+        assertDocsPresentInIndex(client, restoredIndexName2, numDocsInIndex2);
+
+        // deleting data for restoredIndexName1 and restoring from remote store.
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primary));
+        ensureRed(indexName1);
+        // Re-initialize client to make sure we are not using client from stopped node.
+        client = client(clusterManagerNode);
+        assertAcked(client.admin().indices().prepareClose(indexName1));
+        client.admin()
+            .cluster()
+            .restoreRemoteStore(new RestoreRemoteStoreRequest().indices(indexName1).restoreAllShards(true), PlainActionFuture.newFuture());
+        ensureYellowAndNoInitializingShards(indexName1);
+        ensureGreen(indexName1);
+        assertDocsPresentInIndex(client(), indexName1, numDocsInIndex1);
+        // indexing some new docs and validating
+        indexDocuments(client, indexName1, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(indexName1);
+        assertDocsPresentInIndex(client, indexName1, numDocsInIndex1 + 2);
+    }
+
+    public void testRestoreShallowCopySnapshotWithDifferentRepo() throws IOException {
+        String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        String primary = internalCluster().startDataOnlyNode();
+        String indexName1 = "testindex1";
+        String indexName2 = "testindex2";
+        String snapshotRepoName = "test-restore-snapshot-repo";
+        String remoteStoreRepo2Name = "test-rs-repo-2" + TEST_REMOTE_STORE_REPO_SUFFIX;
+        String snapshotName1 = "test-restore-snapshot1";
+        Path absolutePath1 = randomRepoPath().toAbsolutePath();
+        Path absolutePath3 = randomRepoPath().toAbsolutePath();
+        String restoredIndexName1 = indexName1 + "-restored";
+
+        createRepository(snapshotRepoName, "fs", getRepositorySettings(absolutePath1, false));
+        createRepository(remoteStoreRepo2Name, "fs", absolutePath3);
+
+        Client client = client();
+        Settings indexSettings = getIndexSettings(1, 0).build();
+        createIndex(indexName1, indexSettings);
+
+        Settings indexSettings2 = getIndexSettings(1, 0).build();
+        createIndex(indexName2, indexSettings2);
+
+        final int numDocsInIndex1 = 5;
+        final int numDocsInIndex2 = 6;
+        indexDocuments(client, indexName1, numDocsInIndex1);
+        indexDocuments(client, indexName2, numDocsInIndex2);
+        ensureGreen(indexName1, indexName2);
+
+        internalCluster().startDataOnlyNode();
+
+        logger.info("--> snapshot");
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1, indexName2)
+            .get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        Settings remoteStoreIndexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, remoteStoreRepo2Name)
+            .build();
+        // restore index as a remote store index with different remote store repo
+        RestoreSnapshotResponse restoreSnapshotResponse = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(false)
+            .setIndexSettings(remoteStoreIndexSettings)
+            .setIndices(indexName1)
+            .setRenamePattern(indexName1)
+            .setRenameReplacement(restoredIndexName1)
+            .get();
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client(), restoredIndexName1, numDocsInIndex1);
+
+        // deleting data for restoredIndexName1 and restoring from remote store.
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primary));
+        // Re-initialize client to make sure we are not using client from stopped node.
+        client = client(clusterManagerNode);
+        assertAcked(client.admin().indices().prepareClose(restoredIndexName1));
+        client.admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(restoredIndexName1).restoreAllShards(true),
+                PlainActionFuture.newFuture()
+            );
+        ensureYellowAndNoInitializingShards(restoredIndexName1);
+        ensureGreen(restoredIndexName1);
+        // indexing some new docs and validating
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1);
+        indexDocuments(client, restoredIndexName1, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1 + 2);
+    }
+
+    public void testRestoreShallowSnapshotRepository() throws ExecutionException, InterruptedException {
+        String indexName1 = "testindex1";
+        String snapshotRepoName = "test-restore-snapshot-repo";
+        String remoteStoreRepoNameUpdated = "test-rs-repo-updated" + TEST_REMOTE_STORE_REPO_SUFFIX;
+        String snapshotName1 = "test-restore-snapshot1";
+        Path absolutePath1 = randomRepoPath().toAbsolutePath();
+        Path absolutePath2 = randomRepoPath().toAbsolutePath();
+        String[] pathTokens = absolutePath1.toString().split("/");
+        String basePath = pathTokens[pathTokens.length - 1];
+        Arrays.copyOf(pathTokens, pathTokens.length - 1);
+        Path location = PathUtils.get(String.join("/", pathTokens));
+        pathTokens = absolutePath2.toString().split("/");
+        String basePath2 = pathTokens[pathTokens.length - 1];
+        Arrays.copyOf(pathTokens, pathTokens.length - 1);
+        Path location2 = PathUtils.get(String.join("/", pathTokens));
+        logger.info("Path 1 [{}]", absolutePath1);
+        logger.info("Path 2 [{}]", absolutePath2);
+        String restoredIndexName1 = indexName1 + "-restored";
+
+        createRepository(snapshotRepoName, "fs", getRepositorySettings(location, basePath, true));
+
+        Client client = client();
+        Settings indexSettings = Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "300s")
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .build();
+        createIndex(indexName1, indexSettings);
+
+        int numDocsInIndex1 = randomIntBetween(2, 5);
+        indexDocuments(client, indexName1, numDocsInIndex1);
+
+        ensureGreen(indexName1);
+
+        logger.info("--> snapshot");
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1)
+            .get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(
+            createSnapshotResponse.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
+        );
+        assertThat(createSnapshotResponse.getSnapshotInfo().state(), equalTo(SnapshotState.SUCCESS));
+
+        client().admin().indices().close(Requests.closeIndexRequest(indexName1)).get();
+        createRepository(remoteStoreRepoNameUpdated, "fs", remoteRepoPath);
+        RestoreSnapshotResponse restoreSnapshotResponse2 = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(snapshotRepoName, snapshotName1)
+            .setWaitForCompletion(true)
+            .setIndices(indexName1)
+            .setRenamePattern(indexName1)
+            .setRenameReplacement(restoredIndexName1)
+            .setSourceRemoteStoreRepository(remoteStoreRepoNameUpdated)
+            .get();
+
+        assertTrue(restoreSnapshotResponse2.getRestoreInfo().failedShards() == 0);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1);
+
+        // indexing some new docs and validating
+        indexDocuments(client, restoredIndexName1, numDocsInIndex1, numDocsInIndex1 + 2);
+        ensureGreen(restoredIndexName1);
+        assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1 + 2);
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBackpressureIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBackpressureIT.java
new file mode 100644
index 0000000000000..3462054c23630
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBackpressureIT.java
@@ -0,0 +1,159 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStats;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.snapshots.mockstore.MockRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.remote.RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT;
+import static org.opensearch.index.remote.RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreBackpressureIT extends AbstractRemoteStoreMockRepositoryIntegTestCase {
+    public void testWritesRejectedDueToConsecutiveFailureBreach() throws Exception {
+        // Here the doc size of the request remains same throughout the test. After initial indexing, all remote store interactions
+        // fail leading to consecutive failure limit getting exceeded and leading to rejections.
+        validateBackpressure(ByteSizeUnit.KB.toIntBytes(1), 10, ByteSizeUnit.KB.toIntBytes(1), 15, "failure_streak_count");
+    }
+
+    public void testWritesRejectedDueToBytesLagBreach() throws Exception {
+        // Initially indexing happens with doc size of 2 bytes, then all remote store interactions start failing. Now, the
+        // indexing happens with doc size of 1KB leading to bytes lag limit getting exceeded and leading to rejections.
+        validateBackpressure(ByteSizeUnit.BYTES.toIntBytes(2), 30, ByteSizeUnit.KB.toIntBytes(1), 15, "bytes_lag");
+    }
+
+    public void testWritesRejectedDueToTimeLagBreach() throws Exception {
+        // Initially indexing happens with doc size of 1KB, then all remote store interactions start failing. Now, the
+        // indexing happens with doc size of 1 byte leading to time lag limit getting exceeded and leading to rejections.
+        validateBackpressure(ByteSizeUnit.KB.toIntBytes(1), 20, ByteSizeUnit.BYTES.toIntBytes(1), 15, "time_lag");
+    }
+
+    private void validateBackpressure(
+        int initialDocSize,
+        int initialDocsToIndex,
+        int onFailureDocSize,
+        int onFailureDocsToIndex,
+        String breachMode
+    ) throws Exception {
+        Path location = randomRepoPath().toAbsolutePath();
+        String dataNodeName = setup(location, 0d, "metadata", Long.MAX_VALUE);
+
+        Settings request = Settings.builder()
+            .put(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), true)
+            .put(MIN_CONSECUTIVE_FAILURES_LIMIT.getKey(), 10)
+            .build();
+        ClusterUpdateSettingsResponse clusterUpdateResponse = client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setPersistentSettings(request)
+            .get();
+        assertEquals(clusterUpdateResponse.getPersistentSettings().get(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey()), "true");
+        assertEquals(clusterUpdateResponse.getPersistentSettings().get(MIN_CONSECUTIVE_FAILURES_LIMIT.getKey()), "10");
+
+        logger.info("--> Indexing data");
+
+        String jsonString = generateString(initialDocSize);
+        BytesReference initialSource = new BytesArray(jsonString);
+        indexDocAndRefresh(initialSource, initialDocsToIndex);
+
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, dataNodeName).repository(REPOSITORY_NAME))
+            .setRandomControlIOExceptionRate(1d);
+
+        jsonString = generateString(onFailureDocSize);
+        BytesReference onFailureSource = new BytesArray(jsonString);
+        OpenSearchRejectedExecutionException ex = assertThrows(
+            OpenSearchRejectedExecutionException.class,
+            () -> indexDocAndRefresh(onFailureSource, onFailureDocsToIndex)
+        );
+        assertTrue(ex.getMessage().contains("rejected execution on primary shard"));
+        assertTrue(ex.getMessage().contains(breachMode));
+
+        RemoteSegmentTransferTracker.Stats stats = stats();
+        assertTrue(stats.bytesLag > 0);
+        assertTrue(stats.refreshTimeLagMs > 0);
+        assertTrue(stats.localRefreshNumber - stats.remoteRefreshNumber > 0);
+        assertTrue(stats.rejectionCount > 0);
+
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, dataNodeName).repository(REPOSITORY_NAME))
+            .setRandomControlIOExceptionRate(0d);
+
+        assertBusy(() -> {
+            RemoteSegmentTransferTracker.Stats finalStats = stats();
+            assertEquals(0, finalStats.bytesLag);
+            assertEquals(0, finalStats.refreshTimeLagMs);
+            assertEquals(0, finalStats.localRefreshNumber - finalStats.remoteRefreshNumber);
+        }, 30, TimeUnit.SECONDS);
+
+        long rejectionCount = stats.rejectionCount;
+        stats = stats();
+        indexDocAndRefresh(initialSource, initialDocsToIndex);
+        assertEquals(rejectionCount, stats.rejectionCount);
+        cleanupRepo();
+    }
+
+    private RemoteSegmentTransferTracker.Stats stats() {
+        String shardId = "0";
+        RemoteStoreStatsResponse response = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, shardId).get();
+        final String indexShardId = String.format(Locale.ROOT, "[%s][%s]", INDEX_NAME, shardId);
+        List<RemoteStoreStats> matches = Arrays.stream(response.getRemoteStoreStats())
+            .filter(stat -> indexShardId.equals(stat.getSegmentStats().shardId.toString()))
+            .collect(Collectors.toList());
+        assertEquals(1, matches.size());
+        return matches.get(0).getSegmentStats();
+    }
+
+    private void indexDocAndRefresh(BytesReference source, int iterations) {
+        for (int i = 0; i < iterations; i++) {
+            client().prepareIndex(INDEX_NAME).setSource(source, MediaTypeRegistry.JSON).get();
+            refresh(INDEX_NAME);
+        }
+    }
+
+    /**
+     * Generates string of given sizeInBytes
+     *
+     * @param sizeInBytes size of the string
+     * @return the generated string
+     */
+    private String generateString(int sizeInBytes) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("{");
+        int i = 0;
+        // Based on local tests, 1 char is occupying 1 byte
+        while (sb.length() < sizeInBytes) {
+            String key = "field" + i;
+            String value = "value" + i;
+            sb.append("\"").append(key).append("\":\"").append(value).append("\",");
+            i++;
+        }
+        if (sb.length() > 1 && sb.charAt(sb.length() - 1) == ',') {
+            sb.setLength(sb.length() - 1);
+        }
+        sb.append("}");
+        return sb.toString();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBaseIntegTestCase.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBaseIntegTestCase.java
new file mode 100644
index 0000000000000..e2ef5f85abc74
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBaseIntegTestCase.java
@@ -0,0 +1,377 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.bulk.BulkItemResponse;
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.WriteRequest;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+
+import java.io.IOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
+
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+
+public class RemoteStoreBaseIntegTestCase extends OpenSearchIntegTestCase {
+    protected static final String REPOSITORY_NAME = "test-remote-store-repo";
+    protected static final String REPOSITORY_2_NAME = "test-remote-store-repo-2";
+    protected static final int SHARD_COUNT = 1;
+    protected static final int REPLICA_COUNT = 1;
+    protected static final String TOTAL_OPERATIONS = "total-operations";
+    protected static final String REFRESHED_OR_FLUSHED_OPERATIONS = "refreshed-or-flushed-operations";
+    protected static final String MAX_SEQ_NO_TOTAL = "max-seq-no-total";
+    protected static final String MAX_SEQ_NO_REFRESHED_OR_FLUSHED = "max-seq-no-refreshed-or-flushed";
+
+    protected Path segmentRepoPath;
+    protected Path translogRepoPath;
+    protected boolean clusterSettingsSuppliedByTest = false;
+    private final List<String> documentKeys = List.of(
+        randomAlphaOfLength(5),
+        randomAlphaOfLength(5),
+        randomAlphaOfLength(5),
+        randomAlphaOfLength(5),
+        randomAlphaOfLength(5)
+    );
+
+    protected Map<String, Long> indexData(int numberOfIterations, boolean invokeFlush, String index) {
+        long totalOperations = 0;
+        long refreshedOrFlushedOperations = 0;
+        long maxSeqNo = -1;
+        long maxSeqNoRefreshedOrFlushed = -1;
+        int shardId = 0;
+        Map<String, Long> indexingStats = new HashMap<>();
+        for (int i = 0; i < numberOfIterations; i++) {
+            if (invokeFlush) {
+                flushAndRefresh(index);
+            } else {
+                refresh(index);
+            }
+            maxSeqNoRefreshedOrFlushed = maxSeqNo;
+            indexingStats.put(MAX_SEQ_NO_REFRESHED_OR_FLUSHED + "-shard-" + shardId, maxSeqNoRefreshedOrFlushed);
+            refreshedOrFlushedOperations = totalOperations;
+            int numberOfOperations = randomIntBetween(20, 50);
+            int numberOfBulk = randomIntBetween(1, 5);
+            for (int j = 0; j < numberOfBulk; j++) {
+                BulkResponse res = indexBulk(index, numberOfOperations);
+                for (BulkItemResponse singleResp : res.getItems()) {
+                    indexingStats.put(
+                        MAX_SEQ_NO_TOTAL + "-shard-" + singleResp.getResponse().getShardId().id(),
+                        singleResp.getResponse().getSeqNo()
+                    );
+                    maxSeqNo = singleResp.getResponse().getSeqNo();
+                }
+                totalOperations += numberOfOperations;
+            }
+        }
+
+        indexingStats.put(TOTAL_OPERATIONS, totalOperations);
+        indexingStats.put(REFRESHED_OR_FLUSHED_OPERATIONS, refreshedOrFlushedOperations);
+        indexingStats.put(MAX_SEQ_NO_TOTAL, maxSeqNo);
+        indexingStats.put(MAX_SEQ_NO_REFRESHED_OR_FLUSHED, maxSeqNoRefreshedOrFlushed);
+        return indexingStats;
+    }
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        if (segmentRepoPath == null || translogRepoPath == null) {
+            segmentRepoPath = randomRepoPath().toAbsolutePath();
+            translogRepoPath = randomRepoPath().toAbsolutePath();
+        }
+        if (clusterSettingsSuppliedByTest) {
+            return Settings.builder().put(super.nodeSettings(nodeOrdinal)).build();
+        } else {
+            return Settings.builder()
+                .put(super.nodeSettings(nodeOrdinal))
+                .put(remoteStoreClusterSettings(REPOSITORY_NAME, segmentRepoPath, REPOSITORY_2_NAME, translogRepoPath))
+                .build();
+        }
+    }
+
+    public Settings indexSettings() {
+        return defaultIndexSettings();
+    }
+
+    protected IndexResponse indexSingleDoc(String indexName) {
+        return indexSingleDoc(indexName, false);
+    }
+
+    protected IndexResponse indexSingleDoc(String indexName, boolean forceRefresh) {
+        IndexRequestBuilder indexRequestBuilder = client().prepareIndex(indexName)
+            .setId(UUIDs.randomBase64UUID())
+            .setSource(documentKeys.get(randomIntBetween(0, documentKeys.size() - 1)), randomAlphaOfLength(5));
+        if (forceRefresh) {
+            indexRequestBuilder.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
+        }
+        return indexRequestBuilder.get();
+    }
+
+    protected BulkResponse indexBulk(String indexName, int numDocs) {
+        BulkRequest bulkRequest = new BulkRequest();
+        for (int i = 0; i < numDocs; i++) {
+            final IndexRequest request = client().prepareIndex(indexName)
+                .setId(UUIDs.randomBase64UUID())
+                .setSource(documentKeys.get(randomIntBetween(0, documentKeys.size() - 1)), randomAlphaOfLength(5))
+                .request();
+            bulkRequest.add(request);
+        }
+        return client().bulk(bulkRequest).actionGet();
+    }
+
+    public static Settings remoteStoreClusterSettings(String name, Path path) {
+        return remoteStoreClusterSettings(name, path, name, path);
+    }
+
+    public static Settings remoteStoreClusterSettings(
+        String segmentRepoName,
+        Path segmentRepoPath,
+        String segmentRepoType,
+        String translogRepoName,
+        Path translogRepoPath,
+        String translogRepoType
+    ) {
+        Settings.Builder settingsBuilder = Settings.builder();
+        settingsBuilder.put(
+            buildRemoteStoreNodeAttributes(
+                segmentRepoName,
+                segmentRepoPath,
+                segmentRepoType,
+                translogRepoName,
+                translogRepoPath,
+                translogRepoType,
+                false
+            )
+        );
+        return settingsBuilder.build();
+    }
+
+    public static Settings remoteStoreClusterSettings(
+        String segmentRepoName,
+        Path segmentRepoPath,
+        String translogRepoName,
+        Path translogRepoPath
+    ) {
+        Settings.Builder settingsBuilder = Settings.builder();
+        settingsBuilder.put(buildRemoteStoreNodeAttributes(segmentRepoName, segmentRepoPath, translogRepoName, translogRepoPath, false));
+        return settingsBuilder.build();
+    }
+
+    public static Settings buildRemoteStoreNodeAttributes(
+        String segmentRepoName,
+        Path segmentRepoPath,
+        String translogRepoName,
+        Path translogRepoPath,
+        boolean withRateLimiterAttributes
+    ) {
+        return buildRemoteStoreNodeAttributes(
+            segmentRepoName,
+            segmentRepoPath,
+            FsRepository.TYPE,
+            translogRepoName,
+            translogRepoPath,
+            FsRepository.TYPE,
+            withRateLimiterAttributes
+        );
+    }
+
+    public static Settings buildRemoteStoreNodeAttributes(
+        String segmentRepoName,
+        Path segmentRepoPath,
+        String segmentRepoType,
+        String translogRepoName,
+        Path translogRepoPath,
+        String translogRepoType,
+        boolean withRateLimiterAttributes
+    ) {
+        String segmentRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            segmentRepoName
+        );
+        String segmentRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            segmentRepoName
+        );
+        String translogRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            translogRepoName
+        );
+        String translogRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            translogRepoName
+        );
+        String stateRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            segmentRepoName
+        );
+        String stateRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            segmentRepoName
+        );
+
+        Settings.Builder settings = Settings.builder()
+            .put("node.attr." + REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, segmentRepoName)
+            .put(segmentRepoTypeAttributeKey, segmentRepoType)
+            .put(segmentRepoSettingsAttributeKeyPrefix + "location", segmentRepoPath)
+            .put("node.attr." + REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, translogRepoName)
+            .put(translogRepoTypeAttributeKey, translogRepoType)
+            .put(translogRepoSettingsAttributeKeyPrefix + "location", translogRepoPath)
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, segmentRepoName)
+            .put(stateRepoTypeAttributeKey, segmentRepoType)
+            .put(stateRepoSettingsAttributeKeyPrefix + "location", segmentRepoPath);
+
+        if (withRateLimiterAttributes) {
+            settings.put(segmentRepoSettingsAttributeKeyPrefix + "compress", randomBoolean())
+                .put(segmentRepoSettingsAttributeKeyPrefix + "chunk_size", 200, ByteSizeUnit.BYTES);
+        }
+
+        return settings.build();
+    }
+
+    private Settings defaultIndexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, SHARD_COUNT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT)
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "300s")
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    protected Settings remoteStoreIndexSettings(int numberOfReplicas, int numberOfShards) {
+        return Settings.builder()
+            .put(defaultIndexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numberOfShards)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, numberOfReplicas)
+            .build();
+    }
+
+    protected Settings remoteStoreIndexSettings(int numberOfReplicas) {
+        return remoteStoreIndexSettings(numberOfReplicas, 1);
+    }
+
+    protected Settings remoteStoreIndexSettings(int numberOfReplicas, long totalFieldLimit, int refresh) {
+        return Settings.builder()
+            .put(remoteStoreIndexSettings(numberOfReplicas))
+            .put(MapperService.INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING.getKey(), totalFieldLimit)
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), String.valueOf(refresh))
+            .build();
+    }
+
+    @After
+    public void teardown() {
+        clusterSettingsSuppliedByTest = false;
+        assertRemoteStoreRepositoryOnAllNodes(REPOSITORY_NAME);
+        assertRemoteStoreRepositoryOnAllNodes(REPOSITORY_2_NAME);
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_NAME).get();
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_2_NAME).get();
+    }
+
+    public RepositoryMetadata buildRepositoryMetadata(DiscoveryNode node, String name) {
+        Map<String, String> nodeAttributes = node.getAttributes();
+        String type = nodeAttributes.get(String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, name));
+
+        String settingsAttributeKeyPrefix = String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX, name);
+        Map<String, String> settingsMap = node.getAttributes()
+            .keySet()
+            .stream()
+            .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+            .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix, ""), key -> node.getAttributes().get(key)));
+
+        Settings.Builder settings = Settings.builder();
+        settingsMap.entrySet().forEach(entry -> settings.put(entry.getKey(), entry.getValue()));
+        settings.put(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING.getKey(), true);
+
+        return new RepositoryMetadata(name, type, settings.build());
+    }
+
+    public void assertRemoteStoreRepositoryOnAllNodes(String repositoryName) {
+        RepositoriesMetadata repositories = internalCluster().getInstance(ClusterService.class, internalCluster().getNodeNames()[0])
+            .state()
+            .metadata()
+            .custom(RepositoriesMetadata.TYPE);
+        RepositoryMetadata actualRepository = repositories.repository(repositoryName);
+
+        final RepositoriesService repositoriesService = internalCluster().getClusterManagerNodeInstance(RepositoriesService.class);
+        final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(repositoryName);
+
+        for (String nodeName : internalCluster().getNodeNames()) {
+            ClusterService clusterService = internalCluster().getInstance(ClusterService.class, nodeName);
+            DiscoveryNode node = clusterService.localNode();
+            RepositoryMetadata expectedRepository = buildRepositoryMetadata(node, repositoryName);
+
+            // Validated that all the restricted settings are entact on all the nodes.
+            repository.getRestrictedSystemRepositorySettings()
+                .stream()
+                .forEach(setting -> assertEquals(setting.get(actualRepository.settings()), setting.get(expectedRepository.settings())));
+        }
+    }
+
+    public static int getFileCount(Path path) throws Exception {
+        final AtomicInteger filesExisting = new AtomicInteger(0);
+        Files.walkFileTree(path, new SimpleFileVisitor<>() {
+            @Override
+            public FileVisitResult postVisitDirectory(Path dir, IOException impossible) throws IOException {
+                return FileVisitResult.CONTINUE;
+            }
+
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
+                filesExisting.incrementAndGet();
+                return FileVisitResult.CONTINUE;
+            }
+        });
+
+        return filesExisting.get();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreClusterStateRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreClusterStateRestoreIT.java
new file mode 100644
index 0000000000000..5e92bb195680b
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreClusterStateRestoreIT.java
@@ -0,0 +1,288 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreResponse;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.gateway.remote.RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_NODE;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_MAX_SHARDS_PER_CLUSTER_KEY;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreClusterStateRestoreIT extends BaseRemoteStoreRestoreIT {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder().put(super.nodeSettings(nodeOrdinal)).put(REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true).build();
+    }
+
+    private void addNewNodes(int dataNodeCount, int clusterManagerNodeCount) {
+        internalCluster().startNodes(dataNodeCount + clusterManagerNodeCount);
+    }
+
+    private Map<String, Long> initialTestSetup(int shardCount, int replicaCount, int dataNodeCount, int clusterManagerNodeCount) {
+        prepareCluster(clusterManagerNodeCount, dataNodeCount, INDEX_NAME, replicaCount, shardCount);
+        Map<String, Long> indexStats = indexData(1, false, INDEX_NAME);
+        assertEquals(shardCount * (replicaCount + 1), getNumShards(INDEX_NAME).totalNumShards);
+        ensureGreen(INDEX_NAME);
+        return indexStats;
+    }
+
+    private void resetCluster(int dataNodeCount, int clusterManagerNodeCount) {
+        internalCluster().stopAllNodes();
+        addNewNodes(dataNodeCount, clusterManagerNodeCount);
+    }
+
+    private void restoreAndValidate(String clusterUUID, Map<String, Long> indexStats) throws Exception {
+        restoreAndValidate(clusterUUID, indexStats, true);
+    }
+
+    private void restoreAndValidate(String clusterUUID, Map<String, Long> indexStats, boolean validate) throws Exception {
+        // TODO once auto restore is merged, the remote cluster state will be restored
+
+        if (validate) {
+            // Step - 4 validation restore is successful.
+            ensureGreen(INDEX_NAME);
+            verifyRestoredData(indexStats, INDEX_NAME);
+        }
+    }
+
+    private void restoreAndValidateFails(
+        String clusterUUID,
+        PlainActionFuture<RestoreRemoteStoreResponse> actionListener,
+        Class<? extends Throwable> clazz,
+        String errorSubString
+    ) {
+
+        try {
+            restoreAndValidate(clusterUUID, null, false);
+        } catch (Exception e) {
+            assertTrue(
+                String.format(Locale.ROOT, "%s %s", clazz, e),
+                clazz.isAssignableFrom(e.getClass())
+                    || clazz.isAssignableFrom(e.getCause().getClass())
+                    || (e.getCause().getCause() != null && clazz.isAssignableFrom(e.getCause().getCause().getClass()))
+            );
+            assertTrue(
+                String.format(Locale.ROOT, "Error message mismatch. Expected: [%s]. Actual: [%s]", errorSubString, e.getMessage()),
+                e.getMessage().contains(errorSubString)
+            );
+        }
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9834")
+    public void testFullClusterRestore() throws Exception {
+        int shardCount = randomIntBetween(1, 2);
+        int replicaCount = 1;
+        int dataNodeCount = shardCount * (replicaCount + 1);
+        int clusterManagerNodeCount = 1;
+
+        // Step - 1 index some data to generate files in remote directory
+        Map<String, Long> indexStats = initialTestSetup(shardCount, replicaCount, dataNodeCount, 1);
+        String prevClusterUUID = clusterService().state().metadata().clusterUUID();
+
+        // Step - 2 Replace all nodes in the cluster with new nodes. This ensures new cluster state doesn't have previous index metadata
+        resetCluster(dataNodeCount, clusterManagerNodeCount);
+
+        String newClusterUUID = clusterService().state().metadata().clusterUUID();
+        assert !Objects.equals(newClusterUUID, prevClusterUUID) : "cluster restart not successful. cluster uuid is same";
+
+        // Step - 3 Trigger full cluster restore and validate
+        restoreAndValidate(prevClusterUUID, indexStats);
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9834")
+    public void testFullClusterRestoreMultipleIndices() throws Exception {
+        int shardCount = randomIntBetween(1, 2);
+        int replicaCount = 1;
+        int dataNodeCount = shardCount * (replicaCount + 1);
+        int clusterManagerNodeCount = 1;
+
+        // Step - 1 index some data to generate files in remote directory
+        Map<String, Long> indexStats = initialTestSetup(shardCount, replicaCount, dataNodeCount, clusterManagerNodeCount);
+
+        String secondIndexName = INDEX_NAME + "-2";
+        createIndex(secondIndexName, remoteStoreIndexSettings(replicaCount, shardCount + 1));
+        Map<String, Long> indexStats2 = indexData(1, false, secondIndexName);
+        assertEquals((shardCount + 1) * (replicaCount + 1), getNumShards(secondIndexName).totalNumShards);
+        ensureGreen(secondIndexName);
+
+        String prevClusterUUID = clusterService().state().metadata().clusterUUID();
+
+        // Step - 2 Replace all nodes in the cluster with new nodes. This ensures new cluster state doesn't have previous index metadata
+        resetCluster(dataNodeCount, clusterManagerNodeCount);
+
+        String newClusterUUID = clusterService().state().metadata().clusterUUID();
+        assert !Objects.equals(newClusterUUID, prevClusterUUID) : "cluster restart not successful. cluster uuid is same";
+
+        // Step - 3 Trigger full cluster restore
+        restoreAndValidate(prevClusterUUID, indexStats);
+        ensureGreen(secondIndexName);
+        verifyRestoredData(indexStats2, secondIndexName);
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9834")
+    public void testFullClusterRestoreFailureValidationFailures() throws Exception {
+        int shardCount = randomIntBetween(1, 2);
+        int replicaCount = 1;
+        int dataNodeCount = shardCount * (replicaCount + 1);
+        int clusterManagerNodeCount = 1;
+
+        // index some data to generate files in remote directory
+        Map<String, Long> indexStats = initialTestSetup(shardCount, replicaCount, dataNodeCount, clusterManagerNodeCount);
+        String prevClusterUUID = clusterService().state().metadata().clusterUUID();
+
+        // Start of Test - 1
+        // Test - 1 Trigger full cluster restore and validate it fails due to incorrect cluster UUID
+        PlainActionFuture<RestoreRemoteStoreResponse> future = PlainActionFuture.newFuture();
+        restoreAndValidateFails("randomUUID", future, IllegalStateException.class, "Remote Cluster State not found - randomUUID");
+        // End of Test - 1
+
+        // Start of Test - 3
+        // Test - 2 Trigger full cluster restore and validate it fails due to cluster UUID same as current cluster UUID
+        future = PlainActionFuture.newFuture();
+        restoreAndValidateFails(
+            clusterService().state().metadata().clusterUUID(),
+            future,
+            IllegalArgumentException.class,
+            "clusterUUID to restore from should be different from current cluster UUID"
+        );
+        // End of Test - 2
+
+        // Start of Test - 3
+        // Step - 2 Replace all nodes in the cluster with new nodes. This ensures new cluster state doesn't have previous index metadata
+        // Restarting cluster with just 1 data node helps with applying cluster settings
+        resetCluster(1, clusterManagerNodeCount);
+        String newClusterUUID = clusterService().state().metadata().clusterUUID();
+        assert !Objects.equals(newClusterUUID, prevClusterUUID) : "cluster restart not successful. cluster uuid is same";
+
+        reduceShardLimits(1, 1);
+
+        // Step - 4 Trigger full cluster restore and validate it fails
+        future = PlainActionFuture.newFuture();
+        restoreAndValidateFails(
+            prevClusterUUID,
+            future,
+            IllegalArgumentException.class,
+            "this action would add [2] total shards, but this cluster currently has [0]/[1] maximum shards open"
+        );
+        resetShardLimits();
+        // End of Test - 3
+
+        // Start of Test - 4
+        // Test -4 Reset cluster and trigger full restore with same name index in the cluster
+        // Test -4 Add required nodes for this test after last reset.
+        addNewNodes(dataNodeCount - 1, 0);
+
+        newClusterUUID = clusterService().state().metadata().clusterUUID();
+        assert !Objects.equals(newClusterUUID, prevClusterUUID) : "cluster restart not successful. cluster uuid is same";
+
+        // Test -4 Step - 2 Create a new index with same name
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0, 1));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        future = PlainActionFuture.newFuture();
+
+        // Test -4 Step - 3 Trigger full cluster restore and validate fails
+        restoreAndValidateFails(
+            prevClusterUUID,
+            future,
+            IllegalStateException.class,
+            "cannot restore index [remote-store-test-idx-1] because an open index with same name/uuid already exists in the cluster"
+        );
+
+        // Test -4 Step - 4 validation restore is successful.
+        ensureGreen(INDEX_NAME);
+        // End of Test - 4
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9834")
+    public void testFullClusterRestoreManifestFilePointsToInvalidIndexMetadataPathThrowsException() throws Exception {
+        int shardCount = randomIntBetween(1, 2);
+        int replicaCount = 1;
+        int dataNodeCount = shardCount * (replicaCount + 1);
+        int clusterManagerNodeCount = 1;
+
+        // Step - 1 index some data to generate files in remote directory
+        initialTestSetup(shardCount, replicaCount, dataNodeCount, clusterManagerNodeCount);
+
+        String prevClusterUUID = clusterService().state().metadata().clusterUUID();
+
+        // Step - 2 Replace all nodes in the cluster with new nodes. This ensures new cluster state doesn't have previous index metadata
+        resetCluster(dataNodeCount, clusterManagerNodeCount);
+
+        String newClusterUUID = clusterService().state().metadata().clusterUUID();
+        assert !Objects.equals(newClusterUUID, prevClusterUUID) : "cluster restart not successful. cluster uuid is same";
+
+        // Step - 4 Delete index metadata file in remote
+        try {
+            Files.move(
+                segmentRepoPath.resolve(
+                    RemoteClusterStateService.encodeString(clusterService().state().getClusterName().value())
+                        + "/cluster-state/"
+                        + prevClusterUUID
+                        + "/index"
+                ),
+                segmentRepoPath.resolve("cluster-state/")
+            );
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+
+        // Step - 5 Trigger full cluster restore and validate fails
+        PlainActionFuture<RestoreRemoteStoreResponse> future = PlainActionFuture.newFuture();
+        restoreAndValidateFails(prevClusterUUID, future, IllegalStateException.class, "asdsa");
+    }
+
+    private void reduceShardLimits(int maxShardsPerNode, int maxShardsPerCluster) {
+        // Step 3 - Reduce shard limits to hit shard limit with less no of shards
+        try {
+            client().admin()
+                .cluster()
+                .updateSettings(
+                    new ClusterUpdateSettingsRequest().transientSettings(
+                        Settings.builder()
+                            .put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), maxShardsPerNode)
+                            .put(SETTING_MAX_SHARDS_PER_CLUSTER_KEY, maxShardsPerCluster)
+                    )
+                )
+                .get();
+        } catch (InterruptedException | ExecutionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void resetShardLimits() {
+        // Step - 5 Reset the cluster settings
+        ClusterUpdateSettingsRequest resetRequest = new ClusterUpdateSettingsRequest();
+        resetRequest.transientSettings(
+            Settings.builder().putNull(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey()).putNull(SETTING_MAX_SHARDS_PER_CLUSTER_KEY)
+        );
+
+        try {
+            client().admin().cluster().updateSettings(resetRequest).get();
+        } catch (InterruptedException | ExecutionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreForceMergeIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreForceMergeIT.java
new file mode 100644
index 0000000000000..0bcde4b44c734
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreForceMergeIT.java
@@ -0,0 +1,143 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreForceMergeIT extends RemoteStoreBaseIntegTestCase {
+
+    private static final String INDEX_NAME = "remote-store-test-idx-1";
+    private static final String TOTAL_OPERATIONS = "total-operations";
+    private static final String MAX_SEQ_NO_TOTAL = "max-seq-no-total";
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class);
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return remoteStoreIndexSettings(0);
+    }
+
+    private Map<String, Long> indexData(int numberOfIterations, boolean invokeFlush, boolean flushAfterMerge, long deletedDocs) {
+        long totalOperations = 0;
+        long maxSeqNo = -1;
+        List<IndexResponse> indexResponseList = new ArrayList<>();
+        for (int i = 0; i < numberOfIterations; i++) {
+            int numberOfOperations = randomIntBetween(20, 50);
+            for (int j = 0; j < numberOfOperations; j++) {
+                IndexResponse response = indexSingleDoc(INDEX_NAME);
+                maxSeqNo = response.getSeqNo();
+                indexResponseList.add(response);
+            }
+            totalOperations += numberOfOperations;
+            if (invokeFlush) {
+                flush(INDEX_NAME);
+            } else {
+                refresh(INDEX_NAME);
+            }
+        }
+        if (deletedDocs == -1) {
+            deletedDocs = totalOperations;
+        }
+        int length = indexResponseList.size();
+        for (int j = 0; j < deletedDocs; j++) {
+            maxSeqNo = client().prepareDelete().setIndex(INDEX_NAME).setId(indexResponseList.get(length - j - 1).getId()).get().getSeqNo();
+        }
+        client().admin().indices().prepareForceMerge(INDEX_NAME).setMaxNumSegments(1).setFlush(flushAfterMerge).get();
+        refresh(INDEX_NAME);
+        assertHitCount(client().prepareSearch(INDEX_NAME).setSize(0).get(), totalOperations - deletedDocs);
+        Map<String, Long> indexingStats = new HashMap<>();
+        indexingStats.put(TOTAL_OPERATIONS, totalOperations);
+        indexingStats.put(MAX_SEQ_NO_TOTAL, maxSeqNo);
+        return indexingStats;
+    }
+
+    private void verifyRestoredData(Map<String, Long> indexStats, long deletedDocs) {
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        assertHitCount(client().prepareSearch(INDEX_NAME).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS) - deletedDocs);
+        IndexResponse response = indexSingleDoc(INDEX_NAME);
+        assertEquals(indexStats.get(MAX_SEQ_NO_TOTAL) + 1, response.getSeqNo());
+        refresh(INDEX_NAME);
+        assertHitCount(client().prepareSearch(INDEX_NAME).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS) + 1 - deletedDocs);
+    }
+
+    private void testRestoreWithMergeFlow(int numberOfIterations, boolean invokeFlush, boolean flushAfterMerge, long deletedDocs)
+        throws IOException {
+        internalCluster().startNodes(3);
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        Map<String, Long> indexStats = indexData(numberOfIterations, invokeFlush, flushAfterMerge, deletedDocs);
+
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(INDEX_NAME)));
+
+        boolean restoreAllShards = randomBoolean();
+        if (restoreAllShards) {
+            assertAcked(client().admin().indices().prepareClose(INDEX_NAME));
+        }
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(INDEX_NAME).restoreAllShards(restoreAllShards),
+                PlainActionFuture.newFuture()
+            );
+        ensureGreen(INDEX_NAME);
+
+        if (deletedDocs == -1) {
+            verifyRestoredData(indexStats, indexStats.get(TOTAL_OPERATIONS));
+        } else {
+            verifyRestoredData(indexStats, deletedDocs);
+        }
+    }
+
+    // Following integ tests use randomBoolean to control the number of integ tests. If we use the separate
+    // values for each of the flags, number of integ tests become 16 in comparison to current 2.
+    // We have run all the 16 tests on local and they run fine.
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9294")
+    public void testRestoreForceMergeSingleIteration() throws IOException {
+        boolean invokeFLush = randomBoolean();
+        boolean flushAfterMerge = randomBoolean();
+        testRestoreWithMergeFlow(1, invokeFLush, flushAfterMerge, randomIntBetween(0, 10));
+    }
+
+    public void testRestoreForceMergeMultipleIterations() throws IOException {
+        boolean invokeFLush = randomBoolean();
+        boolean flushAfterMerge = randomBoolean();
+        testRestoreWithMergeFlow(randomIntBetween(2, 5), invokeFLush, flushAfterMerge, randomIntBetween(0, 10));
+    }
+
+    public void testRestoreForceMergeMultipleIterationsDeleteAll() throws IOException {
+        boolean invokeFLush = randomBoolean();
+        boolean flushAfterMerge = randomBoolean();
+        testRestoreWithMergeFlow(randomIntBetween(2, 3), invokeFLush, flushAfterMerge, -1);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreIT.java
new file mode 100644
index 0000000000000..1fb5c2052aded
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreIT.java
@@ -0,0 +1,512 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexRequest;
+import org.opensearch.action.admin.indices.get.GetIndexResponse;
+import org.opensearch.action.admin.indices.recovery.RecoveryResponse;
+import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.BufferedAsyncIOProcessor;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.translog.Translog.Durability;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.hamcrest.MatcherAssert;
+
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.index.shard.RemoteStoreRefreshListener.LAST_N_METADATA_FILES_TO_KEEP;
+import static org.opensearch.indices.IndicesService.CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.hamcrest.Matchers.comparesEqualTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.oneOf;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreIT extends RemoteStoreBaseIntegTestCase {
+
+    protected final String INDEX_NAME = "remote-store-test-idx-1";
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class);
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return remoteStoreIndexSettings(0);
+    }
+
+    private void testPeerRecovery(int numberOfIterations, boolean invokeFlush) throws Exception {
+        internalCluster().startNodes(3);
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        Map<String, Long> indexStats = indexData(numberOfIterations, invokeFlush, INDEX_NAME);
+
+        client().admin()
+            .indices()
+            .prepareUpdateSettings(INDEX_NAME)
+            .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+            .get();
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        refresh(INDEX_NAME);
+        String replicaNodeName = replicaNodeName(INDEX_NAME);
+        assertBusy(
+            () -> assertHitCount(client(replicaNodeName).prepareSearch(INDEX_NAME).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS)),
+            30,
+            TimeUnit.SECONDS
+        );
+
+        RecoveryResponse recoveryResponse = client(replicaNodeName).admin().indices().prepareRecoveries().get();
+
+        Optional<RecoveryState> recoverySource = recoveryResponse.shardRecoveryStates()
+            .get(INDEX_NAME)
+            .stream()
+            .filter(rs -> rs.getRecoverySource().getType() == RecoverySource.Type.PEER)
+            .findFirst();
+        assertFalse(recoverySource.isEmpty());
+        // segments_N file is copied to new replica
+        assertEquals(1, recoverySource.get().getIndex().recoveredFileCount());
+
+        IndexResponse response = indexSingleDoc(INDEX_NAME);
+        assertEquals(indexStats.get(MAX_SEQ_NO_TOTAL) + 1, response.getSeqNo());
+        refresh(INDEX_NAME);
+        assertBusy(
+            () -> assertHitCount(client(replicaNodeName).prepareSearch(INDEX_NAME).setSize(0).get(), indexStats.get(TOTAL_OPERATIONS) + 1),
+            30,
+            TimeUnit.SECONDS
+        );
+    }
+
+    public void testPeerRecoveryWithRemoteStoreAndRemoteTranslogNoDataFlush() throws Exception {
+        testPeerRecovery(1, true);
+    }
+
+    public void testPeerRecoveryWithRemoteStoreAndRemoteTranslogFlush() throws Exception {
+        testPeerRecovery(randomIntBetween(2, 5), true);
+    }
+
+    public void testPeerRecoveryWithLowActivityTimeout() throws Exception {
+        ClusterUpdateSettingsRequest req = new ClusterUpdateSettingsRequest().persistentSettings(
+            Settings.builder()
+                .put(RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING.getKey(), "20kb")
+                .put(RecoverySettings.INDICES_RECOVERY_ACTIVITY_TIMEOUT_SETTING.getKey(), "1s")
+        );
+        internalCluster().client().admin().cluster().updateSettings(req).get();
+        testPeerRecovery(randomIntBetween(2, 5), true);
+    }
+
+    public void testPeerRecoveryWithRemoteStoreAndRemoteTranslogNoDataRefresh() throws Exception {
+        testPeerRecovery(1, false);
+    }
+
+    public void testPeerRecoveryWithRemoteStoreAndRemoteTranslogRefresh() throws Exception {
+        testPeerRecovery(randomIntBetween(2, 5), false);
+    }
+
+    private void verifyRemoteStoreCleanup() throws Exception {
+        internalCluster().startNodes(3);
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1));
+
+        indexData(5, randomBoolean(), INDEX_NAME);
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(INDEX_NAME)
+            .get()
+            .getSetting(INDEX_NAME, IndexMetadata.SETTING_INDEX_UUID);
+        Path indexPath = Path.of(String.valueOf(segmentRepoPath), indexUUID);
+        assertTrue(getFileCount(indexPath) > 0);
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+        // Delete is async. Give time for it
+        assertBusy(() -> {
+            try {
+                assertThat(getFileCount(indexPath), comparesEqualTo(0));
+            } catch (Exception e) {}
+        }, 30, TimeUnit.SECONDS);
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9327")
+    public void testRemoteTranslogCleanup() throws Exception {
+        verifyRemoteStoreCleanup();
+    }
+
+    public void testStaleCommitDeletionWithInvokeFlush() throws Exception {
+        internalCluster().startNode();
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1, 10000l, -1));
+        int numberOfIterations = randomIntBetween(5, 15);
+        indexData(numberOfIterations, true, INDEX_NAME);
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(INDEX_NAME)
+            .get()
+            .getSetting(INDEX_NAME, IndexMetadata.SETTING_INDEX_UUID);
+        Path indexPath = Path.of(String.valueOf(segmentRepoPath), indexUUID, "/0/segments/metadata");
+        // Delete is async.
+        assertBusy(() -> {
+            int actualFileCount = getFileCount(indexPath);
+            if (numberOfIterations <= LAST_N_METADATA_FILES_TO_KEEP) {
+                MatcherAssert.assertThat(actualFileCount, is(oneOf(numberOfIterations - 1, numberOfIterations, numberOfIterations + 1)));
+            } else {
+                // As delete is async its possible that the file gets created before the deletion or after
+                // deletion.
+                MatcherAssert.assertThat(
+                    actualFileCount,
+                    is(oneOf(LAST_N_METADATA_FILES_TO_KEEP - 1, LAST_N_METADATA_FILES_TO_KEEP, LAST_N_METADATA_FILES_TO_KEEP + 1))
+                );
+            }
+        }, 30, TimeUnit.SECONDS);
+    }
+
+    public void testStaleCommitDeletionWithoutInvokeFlush() throws Exception {
+        internalCluster().startNode();
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1, 10000l, -1));
+        int numberOfIterations = randomIntBetween(5, 15);
+        indexData(numberOfIterations, false, INDEX_NAME);
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(INDEX_NAME)
+            .get()
+            .getSetting(INDEX_NAME, IndexMetadata.SETTING_INDEX_UUID);
+        Path indexPath = Path.of(String.valueOf(segmentRepoPath), indexUUID, "/0/segments/metadata");
+        int actualFileCount = getFileCount(indexPath);
+        // We also allow (numberOfIterations + 1) as index creation also triggers refresh.
+        MatcherAssert.assertThat(actualFileCount, is(oneOf(numberOfIterations - 1, numberOfIterations, numberOfIterations + 1)));
+    }
+
+    /**
+     * Tests that when the index setting is not passed during index creation, the buffer interval picked up is the cluster
+     * default.
+     */
+    public void testDefaultBufferInterval() throws ExecutionException, InterruptedException {
+        internalCluster().startClusterManagerOnlyNode();
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        String dataNode = internalCluster().startDataOnlyNodes(1).get(0);
+        createIndex(INDEX_NAME);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        assertClusterRemoteBufferInterval(IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL, dataNode);
+
+        IndexShard indexShard = getIndexShard(dataNode);
+        assertTrue(indexShard.getTranslogSyncProcessor() instanceof BufferedAsyncIOProcessor);
+        assertBufferInterval(IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL, indexShard);
+
+        // Next, we change the default buffer interval and the same should reflect in the buffer interval of the index created
+        TimeValue clusterBufferInterval = TimeValue.timeValueSeconds(randomIntBetween(100, 200));
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), clusterBufferInterval))
+            .get();
+        assertBufferInterval(clusterBufferInterval, indexShard);
+        clearClusterBufferIntervalSetting(clusterManagerName);
+    }
+
+    /**
+     * This tests multiple cases where the index setting is passed during the index creation with multiple combinations
+     * with and without cluster default.
+     */
+    public void testOverriddenBufferInterval() throws ExecutionException, InterruptedException {
+        internalCluster().startClusterManagerOnlyNode();
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        String dataNode = internalCluster().startDataOnlyNodes(1).get(0);
+
+        TimeValue bufferInterval = TimeValue.timeValueSeconds(randomIntBetween(0, 100));
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), bufferInterval)
+            .build();
+        createIndex(INDEX_NAME, indexSettings);
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        IndexShard indexShard = getIndexShard(dataNode);
+        assertTrue(indexShard.getTranslogSyncProcessor() instanceof BufferedAsyncIOProcessor);
+        assertBufferInterval(bufferInterval, indexShard);
+
+        // Set the cluster default with a different value, validate that the buffer interval is still the overridden value
+        TimeValue clusterBufferInterval = TimeValue.timeValueSeconds(randomIntBetween(100, 200));
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put(CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), clusterBufferInterval))
+            .get();
+        assertBufferInterval(bufferInterval, indexShard);
+
+        // Set the index setting (index.remote_store.translog.buffer_interval) with a different value and validate that
+        // the buffer interval is updated
+        bufferInterval = TimeValue.timeValueSeconds(bufferInterval.seconds() + randomIntBetween(1, 100));
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), bufferInterval)
+                )
+            )
+            .get();
+        assertBufferInterval(bufferInterval, indexShard);
+
+        // Set the index setting (index.remote_store.translog.buffer_interval) with null and validate the buffer interval
+        // which will be the cluster default now.
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().putNull(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey())
+                )
+            )
+            .get();
+        assertBufferInterval(clusterBufferInterval, indexShard);
+        clearClusterBufferIntervalSetting(clusterManagerName);
+    }
+
+    /**
+     * This tests validation which kicks in during index creation failing creation if the value is less than minimum allowed value.
+     */
+    public void testOverriddenBufferIntervalValidation() {
+        internalCluster().startClusterManagerOnlyNode();
+        TimeValue bufferInterval = TimeValue.timeValueSeconds(-1);
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), bufferInterval)
+            .build();
+        IllegalArgumentException exceptionDuringCreateIndex = assertThrows(
+            IllegalArgumentException.class,
+            () -> createIndex(INDEX_NAME, indexSettings)
+        );
+        assertEquals(
+            "failed to parse value [-1] for setting [index.remote_store.translog.buffer_interval], must be >= [0ms]",
+            exceptionDuringCreateIndex.getMessage()
+        );
+    }
+
+    /**
+     * This tests validation of the cluster setting when being set.
+     */
+    public void testClusterBufferIntervalValidation() {
+        String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
+        IllegalArgumentException exception = assertThrows(
+            IllegalArgumentException.class,
+            () -> client(clusterManagerName).admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(
+                    Settings.builder().put(CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), TimeValue.timeValueSeconds(-1))
+                )
+                .get()
+        );
+        assertEquals(
+            "failed to parse value [-1] for setting [cluster.remote_store.translog.buffer_interval], must be >= [0ms]",
+            exception.getMessage()
+        );
+    }
+
+    public void testRequestDurabilityWhenRestrictSettingExplicitFalse() throws ExecutionException, InterruptedException {
+        // Explicit node settings and request durability
+        testRestrictSettingFalse(true, Durability.REQUEST);
+    }
+
+    public void testAsyncDurabilityWhenRestrictSettingExplicitFalse() throws ExecutionException, InterruptedException {
+        // Explicit node settings and async durability
+        testRestrictSettingFalse(true, Durability.ASYNC);
+    }
+
+    public void testRequestDurabilityWhenRestrictSettingImplicitFalse() throws ExecutionException, InterruptedException {
+        // No node settings and request durability
+        testRestrictSettingFalse(false, Durability.REQUEST);
+    }
+
+    public void testAsyncDurabilityWhenRestrictSettingImplicitFalse() throws ExecutionException, InterruptedException {
+        // No node settings and async durability
+        testRestrictSettingFalse(false, Durability.ASYNC);
+    }
+
+    private void testRestrictSettingFalse(boolean setRestrictFalse, Durability durability) throws ExecutionException, InterruptedException {
+        String clusterManagerName;
+        if (setRestrictFalse) {
+            clusterManagerName = internalCluster().startClusterManagerOnlyNode(
+                Settings.builder().put(IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey(), false).build()
+            );
+        } else {
+            clusterManagerName = internalCluster().startClusterManagerOnlyNode();
+        }
+        String dataNode = internalCluster().startDataOnlyNodes(1).get(0);
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), durability)
+            .build();
+        createIndex(INDEX_NAME, indexSettings);
+        IndexShard indexShard = getIndexShard(dataNode);
+        assertEquals(durability, indexShard.indexSettings().getTranslogDurability());
+
+        durability = randomFrom(Durability.values());
+        client(clusterManagerName).admin()
+            .indices()
+            .updateSettings(
+                new UpdateSettingsRequest(INDEX_NAME).settings(
+                    Settings.builder().put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), durability)
+                )
+            )
+            .get();
+        assertEquals(durability, indexShard.indexSettings().getTranslogDurability());
+    }
+
+    public void testAsyncDurabilityThrowsExceptionWhenRestrictSettingTrue() throws ExecutionException, InterruptedException {
+        String expectedExceptionMsg =
+            "index setting [index.translog.durability=async] is not allowed as cluster setting [cluster.remote_store.index.restrict.async-durability=true]";
+        String clusterManagerName = internalCluster().startClusterManagerOnlyNode(
+            Settings.builder().put(IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey(), true).build()
+        );
+        String dataNode = internalCluster().startDataOnlyNodes(1).get(0);
+
+        // Case 1 - Test create index fails
+        Settings indexSettings = Settings.builder()
+            .put(indexSettings())
+            .put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Durability.ASYNC)
+            .build();
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> createIndex(INDEX_NAME, indexSettings));
+        assertEquals(expectedExceptionMsg, exception.getMessage());
+
+        // Case 2 - Test update index fails
+        createIndex(INDEX_NAME);
+        IndexShard indexShard = getIndexShard(dataNode);
+        assertEquals(Durability.REQUEST, indexShard.indexSettings().getTranslogDurability());
+        exception = assertThrows(
+            IllegalArgumentException.class,
+            () -> client(clusterManagerName).admin()
+                .indices()
+                .updateSettings(new UpdateSettingsRequest(INDEX_NAME).settings(indexSettings))
+                .actionGet()
+        );
+        assertEquals(expectedExceptionMsg, exception.getMessage());
+    }
+
+    private IndexShard getIndexShard(String dataNode) throws ExecutionException, InterruptedException {
+        String clusterManagerName = internalCluster().getClusterManagerName();
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, dataNode);
+        GetIndexResponse getIndexResponse = client(clusterManagerName).admin().indices().getIndex(new GetIndexRequest()).get();
+        String uuid = getIndexResponse.getSettings().get(INDEX_NAME).get(IndexMetadata.SETTING_INDEX_UUID);
+        IndexService indexService = indicesService.indexService(new Index(INDEX_NAME, uuid));
+        return indexService.getShard(0);
+    }
+
+    private void assertClusterRemoteBufferInterval(TimeValue expectedBufferInterval, String dataNode) {
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, dataNode);
+        assertEquals(expectedBufferInterval, indicesService.getClusterRemoteTranslogBufferInterval());
+    }
+
+    private void assertBufferInterval(TimeValue expectedBufferInterval, IndexShard indexShard) {
+        assertEquals(
+            expectedBufferInterval,
+            ((BufferedAsyncIOProcessor<?>) indexShard.getTranslogSyncProcessor()).getBufferIntervalSupplier().get()
+        );
+    }
+
+    private void clearClusterBufferIntervalSetting(String clusterManagerName) {
+        client(clusterManagerName).admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().putNull(CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey()))
+            .get();
+    }
+
+    public void testRestoreSnapshotToIndexWithSameNameDifferentUUID() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
+
+        Path absolutePath = randomRepoPath().toAbsolutePath();
+        assertAcked(
+            clusterAdmin().preparePutRepository("test-repo").setType("fs").setSettings(Settings.builder().put("location", absolutePath))
+        );
+
+        logger.info("--> Create index and ingest 50 docs");
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1));
+        indexBulk(INDEX_NAME, 50);
+        flushAndRefresh(INDEX_NAME);
+
+        String originalIndexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(INDEX_NAME)
+            .get()
+            .getSetting(INDEX_NAME, IndexMetadata.SETTING_INDEX_UUID);
+        assertNotNull(originalIndexUUID);
+        assertNotEquals(IndexMetadata.INDEX_UUID_NA_VALUE, originalIndexUUID);
+
+        ensureGreen();
+
+        logger.info("--> take a snapshot");
+        client().admin().cluster().prepareCreateSnapshot("test-repo", "test-snap").setIndices(INDEX_NAME).setWaitForCompletion(true).get();
+
+        logger.info("--> wipe all indices");
+        cluster().wipeIndices(INDEX_NAME);
+
+        logger.info("--> Create index with the same name, different UUID");
+        assertAcked(
+            prepareCreate(INDEX_NAME).setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 1))
+        );
+
+        ensureGreen(TimeValue.timeValueSeconds(30), INDEX_NAME);
+
+        String newIndexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(INDEX_NAME)
+            .get()
+            .getSetting(INDEX_NAME, IndexMetadata.SETTING_INDEX_UUID);
+        assertNotNull(newIndexUUID);
+        assertNotEquals(IndexMetadata.INDEX_UUID_NA_VALUE, newIndexUUID);
+        assertNotEquals(newIndexUUID, originalIndexUUID);
+
+        logger.info("--> close index");
+        client().admin().indices().prepareClose(INDEX_NAME).get();
+
+        logger.info("--> restore all indices from the snapshot");
+        RestoreSnapshotResponse restoreSnapshotResponse = clusterAdmin().prepareRestoreSnapshot("test-repo", "test-snap")
+            .setWaitForCompletion(true)
+            .execute()
+            .actionGet();
+        assertThat(restoreSnapshotResponse.getRestoreInfo().totalShards(), greaterThan(0));
+
+        flushAndRefresh(INDEX_NAME);
+
+        ensureGreen(INDEX_NAME);
+        assertBusy(() -> {
+            assertHitCount(client(dataNodes.get(0)).prepareSearch(INDEX_NAME).setSize(0).get(), 50);
+            assertHitCount(client(dataNodes.get(1)).prepareSearch(INDEX_NAME).setSize(0).get(), 50);
+        });
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRefreshListenerIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRefreshListenerIT.java
new file mode 100644
index 0000000000000..88760b7bbfad2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRefreshListenerIT.java
@@ -0,0 +1,71 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.index.remote.RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreRefreshListenerIT extends AbstractRemoteStoreMockRepositoryIntegTestCase {
+
+    public void testRemoteRefreshRetryOnFailure() throws Exception {
+
+        Path location = randomRepoPath().toAbsolutePath();
+        setup(location, randomDoubleBetween(0.1, 0.15, true), "metadata", 10L);
+
+        // Here we are having flush/refresh after each iteration of indexing. However, the refresh will not always succeed
+        // due to IOExceptions that are thrown while doing uploadBlobs.
+        indexData(randomIntBetween(5, 10), randomBoolean());
+        logger.info("--> Indexed data");
+
+        // TODO - Once the segments stats api is available, we need to verify that there were failed upload attempts.
+        IndicesStatsResponse response = client().admin().indices().stats(new IndicesStatsRequest()).get();
+        assertEquals(1, response.getShards().length);
+
+        String indexUuid = response.getShards()[0].getShardRouting().index().getUUID();
+        Path segmentDataRepoPath = location.resolve(String.format(Locale.ROOT, "%s/0/segments/data", indexUuid));
+        String segmentDataLocalPath = String.format(Locale.ROOT, "%s/indices/%s/0/index", response.getShards()[0].getDataPath(), indexUuid);
+
+        logger.info("--> Verify that the segment files are same on local and repository eventually");
+        // This can take time as the retry interval is exponential and maxed at 30s
+        assertBusy(() -> {
+            Set<String> filesInLocal = getSegmentFiles(location.getRoot().resolve(segmentDataLocalPath));
+            Set<String> filesInRepo = getSegmentFiles(segmentDataRepoPath);
+            List<String> sortedFilesInLocal = new ArrayList<>(filesInLocal), sortedFilesInRepo = new ArrayList<>(filesInRepo);
+            Collections.sort(sortedFilesInLocal);
+            Collections.sort(sortedFilesInRepo);
+            logger.info("Local files = {}, Repo files = {}", sortedFilesInLocal, sortedFilesInRepo);
+            assertTrue(filesInRepo.containsAll(filesInLocal));
+        }, 90, TimeUnit.SECONDS);
+        cleanupRepo();
+    }
+
+    public void testRemoteRefreshSegmentPressureSettingChanged() {
+        Settings request = Settings.builder().put(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), true).build();
+        ClusterUpdateSettingsResponse response = client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get();
+        assertEquals(response.getPersistentSettings().get(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey()), "true");
+
+        request = Settings.builder().put(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), false).build();
+        response = client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get();
+        assertEquals(response.getPersistentSettings().get(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey()), "false");
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRepositoryRegistrationIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRepositoryRegistrationIT.java
new file mode 100644
index 0000000000000..002a149f0c286
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRepositoryRegistrationIT.java
@@ -0,0 +1,165 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreRepositoryRegistrationIT extends RemoteStoreBaseIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class);
+    }
+
+    public void testSingleNodeClusterRepositoryRegistration() throws Exception {
+        internalCluster().startNode();
+    }
+
+    public void testMultiNodeClusterRepositoryRegistration() throws Exception {
+        internalCluster().startNodes(3);
+    }
+
+    public void testMultiNodeClusterRepositoryRegistrationWithMultipleClusterManager() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
+        internalCluster().startNodes(3);
+    }
+
+    public void testMultiNodeClusterActiveClusterManagerShutDown() throws Exception {
+        internalCluster().startNodes(3);
+        internalCluster().stopCurrentClusterManagerNode();
+        ensureStableCluster(2);
+    }
+
+    public void testMultiNodeClusterActiveMClusterManagerRestart() throws Exception {
+        internalCluster().startNodes(3);
+        String clusterManagerNodeName = internalCluster().getClusterManagerName();
+        internalCluster().restartNode(clusterManagerNodeName);
+        ensureStableCluster(3);
+    }
+
+    public void testMultiNodeClusterRandomNodeRestart() throws Exception {
+        internalCluster().startNodes(3);
+        internalCluster().restartRandomDataNode();
+        ensureStableCluster(3);
+    }
+
+    public void testMultiNodeClusterActiveClusterManagerRecoverNetworkIsolation() {
+        internalCluster().startClusterManagerOnlyNodes(3);
+        String dataNode = internalCluster().startNode();
+
+        NetworkDisruption partition = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
+        internalCluster().setDisruptionScheme(partition);
+
+        partition.startDisrupting();
+        ensureStableCluster(3, dataNode);
+        partition.stopDisrupting();
+
+        ensureStableCluster(4);
+
+        internalCluster().clearDisruptionScheme();
+    }
+
+    public void testMultiNodeClusterRandomNodeRecoverNetworkIsolation() {
+        Set<String> nodesInOneSide = internalCluster().startNodes(3).stream().collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInAnotherSide = internalCluster().startNodes(3).stream().collect(Collectors.toCollection(HashSet::new));
+        ensureStableCluster(6);
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInAnotherSide),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        networkDisruption.startDisrupting();
+        ensureStableCluster(3, nodesInOneSide.stream().findAny().get());
+        networkDisruption.stopDisrupting();
+
+        ensureStableCluster(6);
+
+        internalCluster().clearDisruptionScheme();
+    }
+
+    public void testMultiNodeClusterRandomNodeRecoverNetworkIsolationPostNonRestrictedSettingsUpdate() {
+        Set<String> nodesInOneSide = internalCluster().startNodes(3).stream().collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInAnotherSide = internalCluster().startNodes(3).stream().collect(Collectors.toCollection(HashSet::new));
+        ensureStableCluster(6);
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInAnotherSide),
+            NetworkDisruption.DISCONNECT
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        networkDisruption.startDisrupting();
+
+        final Client client = client(nodesInOneSide.iterator().next());
+        RepositoryMetadata repositoryMetadata = client.admin()
+            .cluster()
+            .prepareGetRepositories(REPOSITORY_NAME)
+            .get()
+            .repositories()
+            .get(0);
+        Settings.Builder updatedSettings = Settings.builder().put(repositoryMetadata.settings()).put("chunk_size", new ByteSizeValue(20));
+        updatedSettings.remove("system_repository");
+
+        client.admin()
+            .cluster()
+            .preparePutRepository(repositoryMetadata.name())
+            .setType(repositoryMetadata.type())
+            .setSettings(updatedSettings)
+            .get();
+
+        ensureStableCluster(3, nodesInOneSide.stream().findAny().get());
+        networkDisruption.stopDisrupting();
+
+        ensureStableCluster(6);
+
+        internalCluster().clearDisruptionScheme();
+    }
+
+    public void testNodeRestartPostNonRestrictedSettingsUpdate() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startNodes(3);
+
+        final Client client = client();
+        RepositoryMetadata repositoryMetadata = client.admin()
+            .cluster()
+            .prepareGetRepositories(REPOSITORY_NAME)
+            .get()
+            .repositories()
+            .get(0);
+        Settings.Builder updatedSettings = Settings.builder().put(repositoryMetadata.settings()).put("chunk_size", new ByteSizeValue(20));
+        updatedSettings.remove("system_repository");
+
+        client.admin()
+            .cluster()
+            .preparePutRepository(repositoryMetadata.name())
+            .setType(repositoryMetadata.type())
+            .setSettings(updatedSettings)
+            .get();
+
+        internalCluster().restartRandomDataNode();
+
+        ensureStableCluster(4);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRestoreIT.java
new file mode 100644
index 0000000000000..7626e3dba6424
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreRestoreIT.java
@@ -0,0 +1,465 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreResponse;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.hamcrest.Matchers.greaterThan;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, numDataNodes = 0)
+public class RemoteStoreRestoreIT extends BaseRemoteStoreRestoreIT {
+
+    /**
+     * Simulates all data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRemoteTranslogRestoreWithNoDataPostCommit() throws Exception {
+        testRestoreFlow(1, true, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates all data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRemoteTranslogRestoreWithNoDataPostRefresh() throws Exception {
+        testRestoreFlow(1, false, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRemoteTranslogRestoreWithRefreshedData() throws Exception {
+        testRestoreFlow(randomIntBetween(2, 5), false, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRemoteTranslogRestoreWithCommittedData() throws Exception {
+        testRestoreFlow(randomIntBetween(2, 5), true, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates all data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreWithNoDataPostCommitPrimaryReplicaDown() throws Exception {
+        testRestoreFlowBothPrimaryReplicasDown(1, true, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates all data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreWithNoDataPostRefreshPrimaryReplicaDown() throws Exception {
+        testRestoreFlowBothPrimaryReplicasDown(1, false, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreWithRefreshedDataPrimaryReplicaDown() throws Exception {
+        testRestoreFlowBothPrimaryReplicasDown(randomIntBetween(2, 5), false, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreWithCommittedDataPrimaryReplicaDown() throws Exception {
+        testRestoreFlowBothPrimaryReplicasDown(randomIntBetween(2, 5), true, randomIntBetween(1, 5));
+    }
+
+    private void restoreAndVerify(int shardCount, int replicaCount, Map<String, Long> indexStats) throws Exception {
+        restore(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+        // This is required to get updated number from already active shards which were not restored
+        assertEquals(shardCount * (1 + replicaCount), getNumShards(INDEX_NAME).totalNumShards);
+        assertEquals(replicaCount, getNumShards(INDEX_NAME).numReplicas);
+        verifyRestoredData(indexStats, INDEX_NAME);
+    }
+
+    /**
+     * Helper function to test restoring an index with no replication from remote store. Only primary node is dropped.
+     * @param numberOfIterations Number of times a refresh/flush should be invoked, followed by indexing some data.
+     * @param invokeFlush If true, a flush is invoked. Otherwise, a refresh is invoked.
+     * @throws IOException IO Exception.
+     */
+    private void testRestoreFlow(int numberOfIterations, boolean invokeFlush, int shardCount) throws Exception {
+        prepareCluster(1, 3, INDEX_NAME, 0, shardCount);
+        Map<String, Long> indexStats = indexData(numberOfIterations, invokeFlush, INDEX_NAME);
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+
+        assertHitCount(client().prepareSearch(INDEX_NAME).setSize(0).get(), indexStats.get(REFRESHED_OR_FLUSHED_OPERATIONS));
+
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(INDEX_NAME)));
+        ensureRed(INDEX_NAME);
+
+        restoreAndVerify(shardCount, 0, indexStats);
+    }
+
+    /**
+     * Helper function to test restoring an index having replicas from remote store when all the nodes housing the primary/replica drop.
+     * @param numberOfIterations Number of times a refresh/flush should be invoked, followed by indexing some data.
+     * @param invokeFlush If true, a flush is invoked. Otherwise, a refresh is invoked.
+     * @throws IOException IO Exception.
+     */
+    private void testRestoreFlowBothPrimaryReplicasDown(int numberOfIterations, boolean invokeFlush, int shardCount) throws Exception {
+        prepareCluster(1, 2, INDEX_NAME, 1, shardCount);
+        Map<String, Long> indexStats = indexData(numberOfIterations, invokeFlush, INDEX_NAME);
+        assertEquals(shardCount * 2, getNumShards(INDEX_NAME).totalNumShards);
+
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(replicaNodeName(INDEX_NAME)));
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(INDEX_NAME)));
+        ensureRed(INDEX_NAME);
+        internalCluster().startDataOnlyNodes(2);
+
+        restoreAndVerify(shardCount, 1, indexStats);
+    }
+
+    /**
+     * Helper function to test restoring multiple indices from remote store when all the nodes housing the primary/replica drop.
+     * @param numberOfIterations Number of times a refresh/flush should be invoked, followed by indexing some data.
+     * @param invokeFlush If true, a flush is invoked. Otherwise, a refresh is invoked.
+     * @throws IOException IO Exception.
+     */
+    private void testRestoreFlowMultipleIndices(int numberOfIterations, boolean invokeFlush, int shardCount) throws Exception {
+        prepareCluster(1, 3, INDEX_NAMES, 1, shardCount);
+        String[] indices = INDEX_NAMES.split(",");
+        Map<String, Map<String, Long>> indicesStats = new HashMap<>();
+        for (String index : indices) {
+            Map<String, Long> indexStats = indexData(numberOfIterations, invokeFlush, index);
+            indicesStats.put(index, indexStats);
+            assertEquals(shardCount * 2, getNumShards(index).totalNumShards);
+        }
+
+        for (String index : indices) {
+            ClusterHealthStatus indexHealth = ensureRed(index);
+            if (ClusterHealthStatus.RED.equals(indexHealth)) {
+                continue;
+            }
+
+            if (ClusterHealthStatus.GREEN.equals(indexHealth)) {
+                internalCluster().stopRandomNode(InternalTestCluster.nameFilter(replicaNodeName(index)));
+            }
+
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(index)));
+        }
+
+        ensureRed(indices);
+        internalCluster().startDataOnlyNodes(3);
+
+        boolean restoreAllShards = randomBoolean();
+        if (restoreAllShards) {
+            assertAcked(client().admin().indices().prepareClose(indices));
+        }
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(INDEX_NAMES_WILDCARD.split(",")).restoreAllShards(restoreAllShards),
+                PlainActionFuture.newFuture()
+            );
+        ensureGreen(indices);
+        for (String index : indices) {
+            assertEquals(shardCount * 2, getNumShards(index).totalNumShards);
+            verifyRestoredData(indicesStats.get(index), index);
+        }
+    }
+
+    public void testRestoreFlowAllShardsNoRedIndex() throws InterruptedException {
+        int shardCount = randomIntBetween(1, 5);
+        prepareCluster(1, 3, INDEX_NAME, 0, shardCount);
+        indexData(randomIntBetween(2, 5), true, INDEX_NAME);
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+
+        PlainActionFuture<RestoreRemoteStoreResponse> future = PlainActionFuture.newFuture();
+        client().admin().cluster().restoreRemoteStore(new RestoreRemoteStoreRequest().indices(INDEX_NAME).restoreAllShards(true), future);
+        try {
+            future.get();
+        } catch (ExecutionException e) {
+            // If the request goes to co-ordinator, e.getCause() can be RemoteTransportException
+            assertTrue(e.getCause() instanceof IllegalStateException || e.getCause().getCause() instanceof IllegalStateException);
+        }
+    }
+
+    public void testRestoreFlowNoRedIndex() throws Exception {
+        int shardCount = randomIntBetween(1, 5);
+        prepareCluster(1, 3, INDEX_NAME, 0, shardCount);
+        Map<String, Long> indexStats = indexData(randomIntBetween(2, 5), true, INDEX_NAME);
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(new RestoreRemoteStoreRequest().indices(INDEX_NAME).restoreAllShards(false), PlainActionFuture.newFuture());
+
+        ensureGreen(INDEX_NAME);
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+        verifyRestoredData(indexStats, INDEX_NAME);
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store
+     * for multiple indices matching a wildcard name pattern.
+     * @throws IOException IO Exception.
+     */
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8480")
+    public void testRTSRestoreWithCommittedDataMultipleIndicesPatterns() throws Exception {
+        testRestoreFlowMultipleIndices(2, true, randomIntBetween(1, 5));
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store,
+     * with all remote-enabled red indices considered for the restore by default.
+     * @throws IOException IO Exception.
+     */
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8480")
+    public void testRTSRestoreWithCommittedDataDefaultAllIndices() throws Exception {
+        int shardCount = randomIntBetween(1, 5);
+        prepareCluster(1, 3, INDEX_NAMES, 1, shardCount);
+        String[] indices = INDEX_NAMES.split(",");
+        Map<String, Map<String, Long>> indicesStats = new HashMap<>();
+        for (String index : indices) {
+            Map<String, Long> indexStats = indexData(2, true, index);
+            indicesStats.put(index, indexStats);
+            assertEquals(shardCount, getNumShards(index).totalNumShards);
+        }
+
+        for (String index : indices) {
+            if (ClusterHealthStatus.RED.equals(ensureRed(index))) {
+                continue;
+            }
+
+            if (ClusterHealthStatus.GREEN.equals(ensureRed(index))) {
+                internalCluster().stopRandomNode(InternalTestCluster.nameFilter(replicaNodeName(index)));
+            }
+
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(index)));
+        }
+
+        ensureRed(indices);
+        internalCluster().startDataOnlyNodes(3);
+
+        restore(indices);
+        ensureGreen(indices);
+
+        for (String index : indices) {
+            assertEquals(shardCount, getNumShards(index).totalNumShards);
+            verifyRestoredData(indicesStats.get(index), index);
+        }
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store,
+     * with only some of the remote-enabled red indices requested for the restore.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreWithCommittedDataNotAllRedRemoteIndices() throws Exception {
+        int shardCount = randomIntBetween(1, 5);
+        prepareCluster(1, 3, INDEX_NAMES, 0, shardCount);
+        String[] indices = INDEX_NAMES.split(",");
+        Map<String, Map<String, Long>> indicesStats = new HashMap<>();
+        for (String index : indices) {
+            Map<String, Long> indexStats = indexData(2, true, index);
+            indicesStats.put(index, indexStats);
+            assertEquals(shardCount, getNumShards(index).totalNumShards);
+        }
+
+        for (String index : indices) {
+            if (ClusterHealthStatus.RED.equals(ensureRed(index))) {
+                continue;
+            }
+
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(index)));
+        }
+
+        ensureRed(indices);
+        internalCluster().startDataOnlyNodes(3);
+
+        boolean restoreAllShards = randomBoolean();
+        if (restoreAllShards) {
+            assertAcked(client().admin().indices().prepareClose(indices[0], indices[1]));
+        }
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices(indices[0], indices[1]).restoreAllShards(restoreAllShards),
+                PlainActionFuture.newFuture()
+            );
+        ensureGreen(indices[0], indices[1]);
+        assertEquals(shardCount, getNumShards(indices[0]).totalNumShards);
+        verifyRestoredData(indicesStats.get(indices[0]), indices[0]);
+        assertEquals(shardCount, getNumShards(indices[1]).totalNumShards);
+        verifyRestoredData(indicesStats.get(indices[1]), indices[1]);
+        ensureRed(indices[2], indices[3]);
+    }
+
+    /**
+     * Simulates refreshed data restored using Remote Segment Store
+     * and unrefreshed data restored using Remote Translog Store,
+     * with all remote-enabled red indices being considered for the restore
+     * except those matching the specified exclusion pattern.
+     * @throws IOException IO Exception.
+     */
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8480")
+    public void testRTSRestoreWithCommittedDataExcludeIndicesPatterns() throws Exception {
+        int shardCount = randomIntBetween(1, 5);
+        prepareCluster(1, 3, INDEX_NAMES, 1, shardCount);
+        String[] indices = INDEX_NAMES.split(",");
+        Map<String, Map<String, Long>> indicesStats = new HashMap<>();
+        for (String index : indices) {
+            Map<String, Long> indexStats = indexData(2, true, index);
+            indicesStats.put(index, indexStats);
+            assertEquals(shardCount, getNumShards(index).totalNumShards);
+        }
+
+        for (String index : indices) {
+            if (ClusterHealthStatus.RED.equals(ensureRed(index))) {
+                continue;
+            }
+
+            if (ClusterHealthStatus.GREEN.equals(ensureRed(index))) {
+                internalCluster().stopRandomNode(InternalTestCluster.nameFilter(replicaNodeName(index)));
+            }
+
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(index)));
+        }
+
+        ensureRed(indices);
+        internalCluster().startDataOnlyNodes(3);
+
+        boolean restoreAllShards = randomBoolean();
+        if (restoreAllShards) {
+            assertAcked(client().admin().indices().prepareClose(indices[0], indices[1]));
+        }
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(
+                new RestoreRemoteStoreRequest().indices("*", "-remote-store-test-index-*").restoreAllShards(restoreAllShards),
+                PlainActionFuture.newFuture()
+            );
+        ensureGreen(indices[0], indices[1]);
+        assertEquals(shardCount, getNumShards(indices[0]).totalNumShards);
+        verifyRestoredData(indicesStats.get(indices[0]), indices[0]);
+        assertEquals(shardCount, getNumShards(indices[1]).totalNumShards);
+        verifyRestoredData(indicesStats.get(indices[1]), indices[1]);
+        ensureRed(indices[2], indices[3]);
+    }
+
+    /**
+     * Simulates no-op restore from remote store,
+     * when the index has no data.
+     * @throws IOException IO Exception.
+     */
+    public void testRTSRestoreDataOnlyInTranslog() throws Exception {
+        testRestoreFlow(0, true, randomIntBetween(1, 5));
+    }
+
+    public void testRateLimitedRemoteDownloads() throws Exception {
+        clusterSettingsSuppliedByTest = true;
+        int shardCount = randomIntBetween(1, 3);
+        Path segmentRepoPath = randomRepoPath();
+        Path tlogRepoPath = randomRepoPath();
+        prepareCluster(
+            1,
+            3,
+            INDEX_NAME,
+            0,
+            shardCount,
+            buildRemoteStoreNodeAttributes(REPOSITORY_NAME, segmentRepoPath, REPOSITORY_2_NAME, tlogRepoPath, true)
+        );
+
+        // validate inplace repository metadata update
+        ClusterService clusterService = internalCluster().getInstance(ClusterService.class);
+        DiscoveryNode node = clusterService.localNode();
+        String settingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            REPOSITORY_NAME
+        );
+        Map<String, String> settingsMap = node.getAttributes()
+            .keySet()
+            .stream()
+            .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+            .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix, ""), key -> node.getAttributes().get(key)));
+        Settings.Builder settings = Settings.builder();
+        settingsMap.entrySet().forEach(entry -> settings.put(entry.getKey(), entry.getValue()));
+        settings.put("location", segmentRepoPath).put("max_remote_download_bytes_per_sec", 4, ByteSizeUnit.KB);
+
+        assertAcked(client().admin().cluster().preparePutRepository(REPOSITORY_NAME).setType("fs").setSettings(settings).get());
+
+        for (RepositoriesService repositoriesService : internalCluster().getDataNodeInstances(RepositoriesService.class)) {
+            Repository segmentRepo = repositoriesService.repository(REPOSITORY_NAME);
+            assertEquals("4096b", segmentRepo.getMetadata().settings().get("max_remote_download_bytes_per_sec"));
+        }
+
+        Map<String, Long> indexStats = indexData(5, false, INDEX_NAME);
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNodeName(INDEX_NAME)));
+        ensureRed(INDEX_NAME);
+        restore(INDEX_NAME);
+        assertBusy(() -> {
+            long downloadPauseTime = 0L;
+            for (RepositoriesService repositoriesService : internalCluster().getDataNodeInstances(RepositoriesService.class)) {
+                downloadPauseTime += repositoriesService.repository(REPOSITORY_NAME).getRemoteDownloadThrottleTimeInNanos();
+            }
+            assertThat(downloadPauseTime, greaterThan(TimeValue.timeValueSeconds(randomIntBetween(3, 5)).nanos()));
+        }, 30, TimeUnit.SECONDS);
+        // Waiting for extended period for green state so that rate limit does not cause flakiness
+        ensureGreen(TimeValue.timeValueSeconds(120), INDEX_NAME);
+        // This is required to get updated number from already active shards which were not restored
+        assertEquals(shardCount, getNumShards(INDEX_NAME).totalNumShards);
+        assertEquals(0, getNumShards(INDEX_NAME).numReplicas);
+        verifyRestoredData(indexStats, INDEX_NAME);
+
+        // revert repo metadata to pass asserts on repo metadata vs. node attrs during teardown
+        // https://github.com/opensearch-project/OpenSearch/pull/9569#discussion_r1345668700
+        settings.remove("max_remote_download_bytes_per_sec");
+        assertAcked(client().admin().cluster().preparePutRepository(REPOSITORY_NAME).setType("fs").setSettings(settings).get());
+        for (RepositoriesService repositoriesService : internalCluster().getDataNodeInstances(RepositoriesService.class)) {
+            Repository segmentRepo = repositoriesService.repository(REPOSITORY_NAME);
+            assertNull(segmentRepo.getMetadata().settings().get("max_remote_download_bytes_per_sec"));
+        }
+    }
+
+    // TODO: Restore flow - index aliases
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsFromNodesStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsFromNodesStatsIT.java
new file mode 100644
index 0000000000000..6e796bdae5a4a
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsFromNodesStatsIT.java
@@ -0,0 +1,209 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
+import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.remote.RemoteSegmentStats;
+import org.opensearch.index.translog.RemoteTranslogStats;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.util.concurrent.TimeUnit;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreStatsFromNodesStatsIT extends RemoteStoreBaseIntegTestCase {
+    private static final String INDEX_NAME = "remote-index-1";
+    private static final int DATA_NODE_COUNT = 2;
+    private static final int CLUSTER_MANAGER_NODE_COUNT = 3;
+
+    @Before
+    public void setup() {
+        setupCustomCluster();
+    }
+
+    private void setupCustomCluster() {
+        internalCluster().startClusterManagerOnlyNodes(CLUSTER_MANAGER_NODE_COUNT);
+        internalCluster().startDataOnlyNodes(DATA_NODE_COUNT);
+        ensureStableCluster(DATA_NODE_COUNT + CLUSTER_MANAGER_NODE_COUNT);
+    }
+
+    /**
+     * - Creates two indices with single primary shard, pinned to a single node.
+     * - Index documents in both of them and forces a fresh for both
+     * - Polls the _remotestore/stats API for individual index level stats
+     * - Adds up requisite fields from the API output, repeats this for the 2nd index
+     * - Polls _nodes/stats and verifies that the total values at node level adds up
+     * to the values capture in the previous step
+     */
+    public void testNodesStatsParityWithOnlyPrimaryShards() {
+        String[] dataNodes = internalCluster().getDataNodeNames().toArray(String[]::new);
+        String randomDataNode = dataNodes[randomIntBetween(0, dataNodes.length - 1)];
+        String firstIndex = INDEX_NAME + "1";
+        String secondIndex = INDEX_NAME + "2";
+
+        // Create first index
+        createIndex(
+            firstIndex,
+            Settings.builder().put(remoteStoreIndexSettings(0, 1)).put("index.routing.allocation.require._name", randomDataNode).build()
+        );
+        ensureGreen(firstIndex);
+        indexSingleDoc(firstIndex, true);
+
+        // Create second index
+        createIndex(
+            secondIndex,
+            Settings.builder().put(remoteStoreIndexSettings(0, 1)).put("index.routing.allocation.require._name", randomDataNode).build()
+        );
+        ensureGreen(secondIndex);
+        indexSingleDoc(secondIndex, true);
+
+        assertNodeStatsParityOnNode(randomDataNode, firstIndex, secondIndex);
+    }
+
+    /**
+     * - Creates two indices with single primary shard and single replica
+     * - Index documents in both of them and forces a fresh for both
+     * - Polls the _remotestore/stats API for individual index level stats
+     * - Adds up requisite fields from the API output for both indices
+     * - Polls _nodes/stats and verifies that the total values at node level adds up
+     * to the values capture in the previous step
+     * - Repeats the above 3 steps for the second node
+     */
+    public void testNodesStatsParityWithReplicaShards() throws Exception {
+        String firstIndex = INDEX_NAME + "1";
+        String secondIndex = INDEX_NAME + "2";
+
+        createIndex(firstIndex, Settings.builder().put(remoteStoreIndexSettings(1, 1)).build());
+        ensureGreen(firstIndex);
+        indexSingleDoc(firstIndex, true);
+
+        // Create second index
+        createIndex(secondIndex, Settings.builder().put(remoteStoreIndexSettings(1, 1)).build());
+        ensureGreen(secondIndex);
+        indexSingleDoc(secondIndex, true);
+
+        assertBusy(() -> assertNodeStatsParityAcrossNodes(firstIndex, secondIndex), 15, TimeUnit.SECONDS);
+    }
+
+    /**
+     * Ensures that node stats shows 0 values for dedicated cluster manager nodes
+     * since cluster manager nodes does not participate in indexing
+     */
+    public void testZeroRemoteStatsOnNodesStatsForClusterManager() {
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureGreen(INDEX_NAME);
+        indexSingleDoc(INDEX_NAME);
+        refresh(INDEX_NAME);
+
+        NodesStatsResponse nodesStatsResponseForClusterManager = client().admin()
+            .cluster()
+            .prepareNodesStats(internalCluster().getClusterManagerName())
+            .setIndices(new CommonStatsFlags().set(CommonStatsFlags.Flag.Segments, true).set(CommonStatsFlags.Flag.Translog, true))
+            .get();
+
+        assertTrue(
+            nodesStatsResponseForClusterManager.getNodes().get(0).getNode().isClusterManagerNode()
+                && !nodesStatsResponseForClusterManager.getNodes().get(0).getNode().isDataNode()
+        );
+        assertZeroRemoteSegmentStats(
+            nodesStatsResponseForClusterManager.getNodes().get(0).getIndices().getSegments().getRemoteSegmentStats()
+        );
+        assertZeroRemoteTranslogStats(
+            nodesStatsResponseForClusterManager.getNodes().get(0).getIndices().getTranslog().getRemoteTranslogStats()
+        );
+
+        NodesStatsResponse nodesStatsResponseForDataNode = client().admin()
+            .cluster()
+            .prepareNodesStats(primaryNodeName(INDEX_NAME))
+            .setIndices(new CommonStatsFlags().set(CommonStatsFlags.Flag.Segments, true).set(CommonStatsFlags.Flag.Translog, true))
+            .get();
+
+        assertTrue(nodesStatsResponseForDataNode.getNodes().get(0).getNode().isDataNode());
+        RemoteSegmentStats remoteSegmentStats = nodesStatsResponseForDataNode.getNodes()
+            .get(0)
+            .getIndices()
+            .getSegments()
+            .getRemoteSegmentStats();
+        assertTrue(remoteSegmentStats.getUploadBytesStarted() > 0);
+        assertTrue(remoteSegmentStats.getUploadBytesSucceeded() > 0);
+
+        RemoteTranslogStats remoteTranslogStats = nodesStatsResponseForDataNode.getNodes()
+            .get(0)
+            .getIndices()
+            .getTranslog()
+            .getRemoteTranslogStats();
+        assertTrue(remoteTranslogStats.getUploadBytesStarted() > 0);
+        assertTrue(remoteTranslogStats.getUploadBytesSucceeded() > 0);
+    }
+
+    private void assertZeroRemoteSegmentStats(RemoteSegmentStats remoteSegmentStats) {
+        // Compare with fresh object because all values default to 0 in default fresh object
+        assertEquals(new RemoteSegmentStats(), remoteSegmentStats);
+    }
+
+    private void assertZeroRemoteTranslogStats(RemoteTranslogStats remoteTranslogStats) {
+        // Compare with fresh object because all values default to 0 in default fresh object
+        assertEquals(new RemoteTranslogStats(), remoteTranslogStats);
+    }
+
+    private static void assertNodeStatsParityAcrossNodes(String... indices) {
+        for (String dataNode : internalCluster().getDataNodeNames()) {
+            assertNodeStatsParityOnNode(dataNode, indices);
+        }
+    }
+
+    private static void assertNodeStatsParityOnNode(String dataNode, String... indices) {
+        RemoteSegmentStats remoteSegmentStatsCumulative = new RemoteSegmentStats();
+        RemoteTranslogStats remoteTranslogStatsCumulative = new RemoteTranslogStats();
+        for (String index : indices) {
+            // Fetch _remotestore/stats
+            RemoteStoreStatsResponse remoteStoreStats = client(dataNode).admin()
+                .cluster()
+                .prepareRemoteStoreStats(index, "0")
+                .setLocal(true)
+                .get();
+            remoteSegmentStatsCumulative.add(new RemoteSegmentStats(remoteStoreStats.getRemoteStoreStats()[0].getSegmentStats()));
+            remoteTranslogStatsCumulative.add(new RemoteTranslogStats(remoteStoreStats.getRemoteStoreStats()[0].getTranslogStats()));
+        }
+
+        // Fetch _nodes/stats
+        NodesStatsResponse nodesStatsResponse = client().admin()
+            .cluster()
+            .prepareNodesStats(dataNode)
+            .setIndices(new CommonStatsFlags().set(CommonStatsFlags.Flag.Segments, true).set(CommonStatsFlags.Flag.Translog, true))
+            .get();
+
+        // assert segment stats
+        RemoteSegmentStats remoteSegmentStatsFromNodesStats = nodesStatsResponse.getNodes()
+            .get(0)
+            .getIndices()
+            .getSegments()
+            .getRemoteSegmentStats();
+        assertEquals(remoteSegmentStatsCumulative, remoteSegmentStatsFromNodesStats);
+        // Ensure that total upload time has non-zero value if there has been segments uploaded from the node
+        if (remoteSegmentStatsCumulative.getUploadBytesStarted() > 0) {
+            assertTrue(remoteSegmentStatsCumulative.getTotalUploadTime() > 0);
+        }
+        // Ensure that total download time has non-zero value if there has been segments downloaded to the node
+        if (remoteSegmentStatsCumulative.getDownloadBytesStarted() > 0) {
+            assertTrue(remoteSegmentStatsCumulative.getTotalDownloadTime() > 0);
+        }
+
+        // assert translog stats
+        RemoteTranslogStats remoteTranslogStatsFromNodesStats = nodesStatsResponse.getNodes()
+            .get(0)
+            .getIndices()
+            .getTranslog()
+            .getRemoteTranslogStats();
+        assertEquals(remoteTranslogStatsCumulative, remoteTranslogStatsFromNodesStats);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsIT.java
new file mode 100644
index 0000000000000..463e960755bd5
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreStatsIT.java
@@ -0,0 +1,701 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStats;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequestBuilder;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteStoreStatsIT extends RemoteStoreBaseIntegTestCase {
+
+    private static final String INDEX_NAME = "remote-store-test-idx-1";
+
+    @Before
+    public void setup() {
+        internalCluster().startNodes(3);
+    }
+
+    public void testStatsResponseFromAllNodes() {
+
+        // Step 1 - We create cluster, create an index, and then index documents into. We also do multiple refreshes/flushes
+        // during this time frame. This ensures that the segment upload has started.
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        indexDocs();
+
+        // Step 2 - We find all the nodes that are present in the cluster. We make the remote store stats api call from
+        // each of the node in the cluster and check that the response is coming as expected.
+        ClusterState state = getClusterState();
+        List<String> nodes = StreamSupport.stream(state.nodes().getNodes().values().spliterator(), false)
+            .map(x -> x.getName())
+            .collect(Collectors.toList());
+        String shardId = "0";
+        for (String node : nodes) {
+            RemoteStoreStatsResponse response = client(node).admin().cluster().prepareRemoteStoreStats(INDEX_NAME, shardId).get();
+            assertTrue(response.getSuccessfulShards() > 0);
+            assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length != 0);
+            final String indexShardId = String.format(Locale.ROOT, "[%s][%s]", INDEX_NAME, shardId);
+            List<RemoteStoreStats> matches = Arrays.stream(response.getRemoteStoreStats())
+                .filter(stat -> indexShardId.equals(stat.getSegmentStats().shardId.toString()))
+                .collect(Collectors.toList());
+            assertEquals(1, matches.size());
+
+            RemoteSegmentTransferTracker.Stats segmentStats = matches.get(0).getSegmentStats();
+            validateSegmentUploadStats(segmentStats);
+            assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+            RemoteTranslogTransferTracker.Stats translogStats = matches.get(0).getTranslogStats();
+            assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+            assertZeroTranslogDownloadStats(translogStats);
+        }
+
+        // Step 3 - Enable replicas on the existing indices and ensure that download
+        // stats are being populated as well
+        changeReplicaCountAndEnsureGreen(1);
+        for (String node : nodes) {
+            RemoteStoreStatsResponse response = client(node).admin().cluster().prepareRemoteStoreStats(INDEX_NAME, shardId).get();
+            assertTrue(response.getSuccessfulShards() > 0);
+            assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length != 0);
+            final String indexShardId = String.format(Locale.ROOT, "[%s][%s]", INDEX_NAME, shardId);
+            List<RemoteStoreStats> matches = Arrays.stream(response.getRemoteStoreStats())
+                .filter(stat -> indexShardId.equals(stat.getSegmentStats().shardId.toString()))
+                .collect(Collectors.toList());
+            assertEquals(2, matches.size());
+            for (RemoteStoreStats stat : matches) {
+                ShardRouting routing = stat.getShardRouting();
+                validateShardRouting(routing);
+                RemoteSegmentTransferTracker.Stats segmentStats = stat.getSegmentStats();
+                RemoteTranslogTransferTracker.Stats translogStats = stat.getTranslogStats();
+                if (routing.primary()) {
+                    validateSegmentUploadStats(segmentStats);
+                    assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+                    assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+                    assertZeroTranslogDownloadStats(translogStats);
+                } else {
+                    validateSegmentDownloadStats(segmentStats);
+                    assertEquals(0, segmentStats.totalUploadsStarted);
+
+                    assertZeroTranslogUploadStats(translogStats);
+                    assertZeroTranslogDownloadStats(translogStats);
+                }
+            }
+        }
+    }
+
+    public void testStatsResponseAllShards() {
+
+        // Step 1 - We create cluster, create an index, and then index documents into. We also do multiple refreshes/flushes
+        // during this time frame. This ensures that the segment upload has started.
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0, 3));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        indexDocs();
+
+        // Step 2 - We find all the nodes that are present in the cluster. We make the remote store stats api call from
+        // each of the node in the cluster and check that the response is coming as expected.
+        ClusterState state = getClusterState();
+        String node = StreamSupport.stream(state.nodes().getDataNodes().values().spliterator(), false)
+            .map(x -> x.getName())
+            .findFirst()
+            .get();
+        RemoteStoreStatsRequestBuilder remoteStoreStatsRequestBuilder = client(node).admin()
+            .cluster()
+            .prepareRemoteStoreStats(INDEX_NAME, null);
+        RemoteStoreStatsResponse response = remoteStoreStatsRequestBuilder.get();
+        assertEquals(3, response.getSuccessfulShards());
+        assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length == 3);
+
+        RemoteSegmentTransferTracker.Stats segmentStats = response.getRemoteStoreStats()[0].getSegmentStats();
+        validateSegmentUploadStats(segmentStats);
+        assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+        RemoteTranslogTransferTracker.Stats translogStats = response.getRemoteStoreStats()[0].getTranslogStats();
+        assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+        assertZeroTranslogDownloadStats(translogStats);
+
+        // Step 3 - Enable replicas on the existing indices and ensure that download
+        // stats are being populated as well
+        changeReplicaCountAndEnsureGreen(1);
+        response = client(node).admin().cluster().prepareRemoteStoreStats(INDEX_NAME, null).get();
+        assertEquals(6, response.getSuccessfulShards());
+        assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length == 6);
+        for (RemoteStoreStats stat : response.getRemoteStoreStats()) {
+            ShardRouting routing = stat.getShardRouting();
+            validateShardRouting(routing);
+            segmentStats = stat.getSegmentStats();
+            translogStats = stat.getTranslogStats();
+            if (routing.primary()) {
+                validateSegmentUploadStats(segmentStats);
+                assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+                assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+                assertZeroTranslogDownloadStats(translogStats);
+            } else {
+                validateSegmentDownloadStats(segmentStats);
+                assertEquals(0, segmentStats.totalUploadsStarted);
+
+                assertZeroTranslogUploadStats(translogStats);
+                assertZeroTranslogDownloadStats(translogStats);
+            }
+        }
+
+    }
+
+    public void testStatsResponseFromLocalNode() {
+
+        // Step 1 - We create cluster, create an index, and then index documents into. We also do multiple refreshes/flushes
+        // during this time frame. This ensures that the segment upload has started.
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0, 3));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        indexDocs();
+
+        // Step 2 - We find a data node in the cluster. We make the remote store stats api call from
+        // each of the data node in the cluster and check that only local shards are returned.
+        ClusterState state = getClusterState();
+        List<String> nodes = StreamSupport.stream(state.nodes().getDataNodes().values().spliterator(), false)
+            .map(x -> x.getName())
+            .collect(Collectors.toList());
+        for (String node : nodes) {
+            RemoteStoreStatsRequestBuilder remoteStoreStatsRequestBuilder = client(node).admin()
+                .cluster()
+                .prepareRemoteStoreStats(INDEX_NAME, null);
+            remoteStoreStatsRequestBuilder.setLocal(true);
+            RemoteStoreStatsResponse response = remoteStoreStatsRequestBuilder.get();
+            assertEquals(1, response.getSuccessfulShards());
+            assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length == 1);
+            RemoteSegmentTransferTracker.Stats segmentStats = response.getRemoteStoreStats()[0].getSegmentStats();
+            validateSegmentUploadStats(segmentStats);
+            assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+            RemoteTranslogTransferTracker.Stats translogStats = response.getRemoteStoreStats()[0].getTranslogStats();
+            assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+            assertZeroTranslogDownloadStats(translogStats);
+        }
+        changeReplicaCountAndEnsureGreen(1);
+        for (String node : nodes) {
+            RemoteStoreStatsRequestBuilder remoteStoreStatsRequestBuilder = client(node).admin()
+                .cluster()
+                .prepareRemoteStoreStats(INDEX_NAME, null);
+            remoteStoreStatsRequestBuilder.setLocal(true);
+            RemoteStoreStatsResponse response = remoteStoreStatsRequestBuilder.get();
+            assertTrue(response.getSuccessfulShards() > 0);
+            assertTrue(response.getRemoteStoreStats() != null && response.getRemoteStoreStats().length != 0);
+            for (RemoteStoreStats stat : response.getRemoteStoreStats()) {
+                ShardRouting routing = stat.getShardRouting();
+                validateShardRouting(routing);
+                RemoteSegmentTransferTracker.Stats segmentStats = stat.getSegmentStats();
+                RemoteTranslogTransferTracker.Stats translogStats = stat.getTranslogStats();
+                if (routing.primary()) {
+                    validateSegmentUploadStats(segmentStats);
+                    assertEquals(0, segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted);
+
+                    assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+                    assertZeroTranslogDownloadStats(translogStats);
+                } else {
+                    validateSegmentDownloadStats(segmentStats);
+                    assertEquals(0, segmentStats.totalUploadsStarted);
+
+                    assertZeroTranslogUploadStats(translogStats);
+                    assertZeroTranslogDownloadStats(translogStats);
+                }
+            }
+        }
+    }
+
+    public void testDownloadStatsCorrectnessSinglePrimarySingleReplica() throws Exception {
+        // Scenario:
+        // - Create index with single primary and single replica shard
+        // - Disable Refresh Interval for the index
+        // - Index documents
+        // - Trigger refresh and flush
+        // - Assert that download stats == upload stats
+        // - Repeat this step for random times (between 5 and 10)
+
+        // Create index with 1 pri and 1 replica and refresh interval disabled
+        createIndex(
+            INDEX_NAME,
+            Settings.builder().put(remoteStoreIndexSettings(1, 1)).put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), -1).build()
+        );
+        ensureGreen(INDEX_NAME);
+
+        // Manually invoke a refresh
+        refresh(INDEX_NAME);
+
+        // Get zero state values
+        // Extract and assert zero state primary stats
+        RemoteStoreStatsResponse zeroStateResponse = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+        RemoteSegmentTransferTracker.Stats zeroStatePrimaryStats = Arrays.stream(zeroStateResponse.getRemoteStoreStats())
+            .filter(remoteStoreStats -> remoteStoreStats.getShardRouting().primary())
+            .collect(Collectors.toList())
+            .get(0)
+            .getSegmentStats();
+        assertTrue(
+            zeroStatePrimaryStats.totalUploadsStarted == zeroStatePrimaryStats.totalUploadsSucceeded
+                && zeroStatePrimaryStats.totalUploadsSucceeded == 1
+        );
+        assertTrue(
+            zeroStatePrimaryStats.uploadBytesStarted == zeroStatePrimaryStats.uploadBytesSucceeded
+                && zeroStatePrimaryStats.uploadBytesSucceeded > 0
+        );
+        assertTrue(zeroStatePrimaryStats.totalUploadsFailed == 0 && zeroStatePrimaryStats.uploadBytesFailed == 0);
+
+        // Extract and assert zero state replica stats
+        RemoteSegmentTransferTracker.Stats zeroStateReplicaStats = Arrays.stream(zeroStateResponse.getRemoteStoreStats())
+            .filter(remoteStoreStats -> !remoteStoreStats.getShardRouting().primary())
+            .collect(Collectors.toList())
+            .get(0)
+            .getSegmentStats();
+        assertTrue(
+            zeroStateReplicaStats.directoryFileTransferTrackerStats.transferredBytesStarted == 0
+                && zeroStateReplicaStats.directoryFileTransferTrackerStats.transferredBytesSucceeded == 0
+        );
+
+        // Index documents
+        for (int i = 1; i <= randomIntBetween(5, 10); i++) {
+            indexSingleDoc(INDEX_NAME);
+            // Running Flush & Refresh manually
+            flushAndRefresh(INDEX_NAME);
+            ensureGreen(INDEX_NAME);
+
+            // Poll for RemoteStore Stats
+            assertBusy(() -> {
+                RemoteStoreStatsResponse response = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+                // Iterate through the response and extract the relevant segment upload and download stats
+                List<RemoteStoreStats> primaryStatsList = Arrays.stream(response.getRemoteStoreStats())
+                    .filter(remoteStoreStats -> remoteStoreStats.getShardRouting().primary())
+                    .collect(Collectors.toList());
+                assertEquals(1, primaryStatsList.size());
+                List<RemoteStoreStats> replicaStatsList = Arrays.stream(response.getRemoteStoreStats())
+                    .filter(remoteStoreStats -> !remoteStoreStats.getShardRouting().primary())
+                    .collect(Collectors.toList());
+                assertEquals(1, replicaStatsList.size());
+                RemoteSegmentTransferTracker.Stats primaryStats = primaryStatsList.get(0).getSegmentStats();
+                RemoteSegmentTransferTracker.Stats replicaStats = replicaStatsList.get(0).getSegmentStats();
+                // Assert Upload syncs - zero state uploads == download syncs
+                assertTrue(primaryStats.totalUploadsStarted > 0);
+                assertTrue(primaryStats.totalUploadsSucceeded > 0);
+                assertTrue(
+                    replicaStats.directoryFileTransferTrackerStats.transferredBytesStarted > 0
+                        && primaryStats.uploadBytesStarted
+                            - zeroStatePrimaryStats.uploadBytesStarted >= replicaStats.directoryFileTransferTrackerStats.transferredBytesStarted
+                );
+                assertTrue(
+                    replicaStats.directoryFileTransferTrackerStats.transferredBytesSucceeded > 0
+                        && primaryStats.uploadBytesSucceeded
+                            - zeroStatePrimaryStats.uploadBytesSucceeded >= replicaStats.directoryFileTransferTrackerStats.transferredBytesSucceeded
+                );
+                // Assert zero failures
+                assertEquals(0, primaryStats.uploadBytesFailed);
+                assertEquals(0, replicaStats.directoryFileTransferTrackerStats.transferredBytesFailed);
+            }, 60, TimeUnit.SECONDS);
+        }
+    }
+
+    public void testDownloadStatsCorrectnessSinglePrimaryMultipleReplicaShards() throws Exception {
+        // Scenario:
+        // - Create index with single primary and N-1 replica shards (N = no of data nodes)
+        // - Disable Refresh Interval for the index
+        // - Index documents
+        // - Trigger refresh and flush
+        // - Assert that download stats == upload stats
+        // - Repeat this step for random times (between 5 and 10)
+
+        // Create index
+        int dataNodeCount = client().admin().cluster().prepareHealth().get().getNumberOfDataNodes();
+        createIndex(
+            INDEX_NAME,
+            Settings.builder()
+                .put(remoteStoreIndexSettings(dataNodeCount - 1, 1))
+                .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), -1)
+                .build()
+        );
+        ensureGreen(INDEX_NAME);
+
+        // Manually invoke a refresh
+        refresh(INDEX_NAME);
+
+        // Get zero state values
+        // Extract and assert zero state primary stats
+        RemoteStoreStatsResponse zeroStateResponse = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+        RemoteSegmentTransferTracker.Stats zeroStatePrimaryStats = Arrays.stream(zeroStateResponse.getRemoteStoreStats())
+            .filter(remoteStoreStats -> remoteStoreStats.getShardRouting().primary())
+            .collect(Collectors.toList())
+            .get(0)
+            .getSegmentStats();
+        assertTrue(
+            zeroStatePrimaryStats.totalUploadsStarted == zeroStatePrimaryStats.totalUploadsSucceeded
+                && zeroStatePrimaryStats.totalUploadsSucceeded == 1
+        );
+        assertTrue(
+            zeroStatePrimaryStats.uploadBytesStarted == zeroStatePrimaryStats.uploadBytesSucceeded
+                && zeroStatePrimaryStats.uploadBytesSucceeded > 0
+        );
+        assertTrue(zeroStatePrimaryStats.totalUploadsFailed == 0 && zeroStatePrimaryStats.uploadBytesFailed == 0);
+
+        // Extract and assert zero state replica stats
+        List<RemoteStoreStats> zeroStateReplicaStats = Arrays.stream(zeroStateResponse.getRemoteStoreStats())
+            .filter(remoteStoreStats -> !remoteStoreStats.getShardRouting().primary())
+            .collect(Collectors.toList());
+        zeroStateReplicaStats.forEach(stats -> {
+            assertTrue(
+                stats.getSegmentStats().directoryFileTransferTrackerStats.transferredBytesStarted == 0
+                    && stats.getSegmentStats().directoryFileTransferTrackerStats.transferredBytesSucceeded == 0
+            );
+        });
+
+        int currentNodesInCluster = client().admin().cluster().prepareHealth().get().getNumberOfDataNodes();
+        for (int i = 0; i < randomIntBetween(5, 10); i++) {
+            indexSingleDoc(INDEX_NAME);
+            // Running Flush & Refresh manually
+            flushAndRefresh(INDEX_NAME);
+
+            assertBusy(() -> {
+                RemoteStoreStatsResponse response = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+                assertEquals(currentNodesInCluster, response.getSuccessfulShards());
+                long uploadsStarted = 0, uploadsSucceeded = 0, uploadsFailed = 0;
+                long uploadBytesStarted = 0, uploadBytesSucceeded = 0, uploadBytesFailed = 0;
+                List<Long> downloadBytesStarted = new ArrayList<>(), downloadBytesSucceeded = new ArrayList<>(), downloadBytesFailed =
+                    new ArrayList<>();
+
+                // Assert that stats for primary shard and replica shard set are equal
+                for (RemoteStoreStats eachStatsObject : response.getRemoteStoreStats()) {
+                    RemoteSegmentTransferTracker.Stats stats = eachStatsObject.getSegmentStats();
+                    if (eachStatsObject.getShardRouting().primary()) {
+                        uploadBytesStarted = stats.uploadBytesStarted;
+                        uploadBytesSucceeded = stats.uploadBytesSucceeded;
+                        uploadBytesFailed = stats.uploadBytesFailed;
+                    } else {
+                        downloadBytesStarted.add(stats.directoryFileTransferTrackerStats.transferredBytesStarted);
+                        downloadBytesSucceeded.add(stats.directoryFileTransferTrackerStats.transferredBytesSucceeded);
+                        downloadBytesFailed.add(stats.directoryFileTransferTrackerStats.transferredBytesFailed);
+                    }
+                }
+
+                assertEquals(0, uploadsFailed);
+                assertEquals(0, uploadBytesFailed);
+                for (int j = 0; j < response.getSuccessfulShards() - 1; j++) {
+                    assertTrue(uploadBytesStarted - zeroStatePrimaryStats.uploadBytesStarted > downloadBytesStarted.get(j));
+                    assertTrue(uploadBytesSucceeded - zeroStatePrimaryStats.uploadBytesSucceeded > downloadBytesSucceeded.get(j));
+                    assertEquals(0, (long) downloadBytesFailed.get(j));
+                }
+            }, 60, TimeUnit.SECONDS);
+        }
+    }
+
+    public void testStatsOnShardRelocation() {
+        // Scenario:
+        // - Create index with single primary and single replica shard
+        // - Index documents
+        // - Reroute replica shard to one of the remaining nodes
+        // - Assert that remote store stats reflects the new node ID
+
+        // Create index
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1, 1));
+        ensureGreen(INDEX_NAME);
+        // Index docs
+        indexDocs();
+
+        // Fetch current set of nodes in the cluster
+        List<String> currentNodesInCluster = getClusterState().nodes()
+            .getDataNodes()
+            .values()
+            .stream()
+            .map(DiscoveryNode::getId)
+            .collect(Collectors.toList());
+        DiscoveryNode[] discoveryNodesForIndex = client().admin().cluster().prepareSearchShards(INDEX_NAME).get().getNodes();
+
+        // Fetch nodes with shard copies of the created index
+        List<String> nodeIdsWithShardCopies = new ArrayList<>();
+        Arrays.stream(discoveryNodesForIndex).forEach(eachNode -> nodeIdsWithShardCopies.add(eachNode.getId()));
+
+        // Fetch nodes which does not have any copies of the index
+        List<String> nodeIdsWithoutShardCopy = currentNodesInCluster.stream()
+            .filter(eachNode -> !nodeIdsWithShardCopies.contains(eachNode))
+            .collect(Collectors.toList());
+        assertEquals(1, nodeIdsWithoutShardCopy.size());
+
+        // Manually reroute shard to a node which does not have any shard copy at present
+        ShardRouting replicaShardRouting = getClusterState().routingTable()
+            .index(INDEX_NAME)
+            .shard(0)
+            .assignedShards()
+            .stream()
+            .filter(shard -> !shard.primary())
+            .collect(Collectors.toList())
+            .get(0);
+        String sourceNode = replicaShardRouting.currentNodeId();
+        String destinationNode = nodeIdsWithoutShardCopy.get(0);
+        relocateShard(0, sourceNode, destinationNode);
+        RemoteStoreStats[] allShardsStats = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get().getRemoteStoreStats();
+        RemoteStoreStats replicaShardStat = Arrays.stream(allShardsStats)
+            .filter(eachStat -> !eachStat.getShardRouting().primary())
+            .collect(Collectors.toList())
+            .get(0);
+
+        // Assert that remote store stats reflect the new shard state
+        assertEquals(ShardRoutingState.STARTED, replicaShardStat.getShardRouting().state());
+        assertEquals(destinationNode, replicaShardStat.getShardRouting().currentNodeId());
+    }
+
+    public void testStatsOnShardUnassigned() throws IOException {
+        // Scenario:
+        // - Create index with single primary and two replica shard
+        // - Index documents
+        // - Stop one data node
+        // - Assert:
+        // a. Total shard Count in the response object is equal to the previous node count
+        // b. Successful shard count in the response object is equal to the new node count
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(2, 1));
+        ensureGreen(INDEX_NAME);
+        indexDocs();
+        ClusterHealthResponse clusterHealthResponse = client().admin().cluster().prepareHealth().get();
+        int dataNodeCountBeforeStop = clusterHealthResponse.getNumberOfDataNodes();
+        int nodeCount = clusterHealthResponse.getNumberOfNodes();
+        String nodeToBeStopped = randomBoolean() ? primaryNodeName(INDEX_NAME) : replicaNodeName(INDEX_NAME);
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeToBeStopped));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureStableCluster(nodeCount - 1);
+        RemoteStoreStatsResponse response = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+        int dataNodeCountAfterStop = client().admin().cluster().prepareHealth().get().getNumberOfDataNodes();
+        assertEquals(dataNodeCountBeforeStop, response.getTotalShards());
+        assertEquals(dataNodeCountAfterStop, response.getSuccessfulShards());
+        // Indexing docs to ensure that the primary has started
+        indexSingleDoc(INDEX_NAME);
+    }
+
+    public void testStatsOnRemoteStoreRestore() throws IOException {
+        // Creating an index with primary shard count == total nodes in cluster and 0 replicas
+        int dataNodeCount = client().admin().cluster().prepareHealth().get().getNumberOfDataNodes();
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0, dataNodeCount));
+        ensureGreen(INDEX_NAME);
+
+        // Index some docs to ensure segments being uploaded to remote store
+        indexDocs();
+        refresh(INDEX_NAME);
+
+        // Stop one data node to force the index into a red state
+        internalCluster().stopRandomDataNode();
+        ensureRed(INDEX_NAME);
+
+        // Start another data node to fulfil the previously launched capacity
+        internalCluster().startDataOnlyNode();
+
+        // Restore index from remote store
+        assertAcked(client().admin().indices().prepareClose(INDEX_NAME));
+        client().admin()
+            .cluster()
+            .restoreRemoteStore(new RestoreRemoteStoreRequest().indices(INDEX_NAME).restoreAllShards(true), PlainActionFuture.newFuture());
+
+        // Ensure that the index is green
+        ensureGreen(INDEX_NAME);
+
+        // Index some more docs to force segment uploads to remote store
+        indexDocs();
+
+        RemoteStoreStatsResponse remoteStoreStatsResponse = client().admin().cluster().prepareRemoteStoreStats(INDEX_NAME, "0").get();
+        Arrays.stream(remoteStoreStatsResponse.getRemoteStoreStats()).forEach(statObject -> {
+            RemoteSegmentTransferTracker.Stats segmentStats = statObject.getSegmentStats();
+            // Assert that we have both upload and download stats for the index
+            assertTrue(
+                segmentStats.totalUploadsStarted > 0 && segmentStats.totalUploadsSucceeded > 0 && segmentStats.totalUploadsFailed == 0
+            );
+            assertTrue(
+                segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted > 0
+                    && segmentStats.directoryFileTransferTrackerStats.transferredBytesSucceeded > 0
+            );
+
+            RemoteTranslogTransferTracker.Stats translogStats = statObject.getTranslogStats();
+            assertNonZeroTranslogUploadStatsNoFailures(translogStats);
+            assertNonZeroTranslogDownloadStats(translogStats);
+        });
+    }
+
+    public void testNonZeroPrimaryStatsOnNewlyCreatedIndexWithZeroDocs() throws Exception {
+        // Create an index with one primary and one replica shard
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(1, 1));
+        ensureGreen(INDEX_NAME);
+        refresh(INDEX_NAME);
+
+        // Ensure that the index has 0 documents in it
+        assertEquals(0, client().admin().indices().prepareStats(INDEX_NAME).get().getTotal().docs.getCount());
+
+        // Assert that within 5 seconds the download and upload stats moves to a non-zero value
+        assertBusy(() -> {
+            RemoteStoreStats[] remoteStoreStats = client().admin()
+                .cluster()
+                .prepareRemoteStoreStats(INDEX_NAME, "0")
+                .get()
+                .getRemoteStoreStats();
+            Arrays.stream(remoteStoreStats).forEach(statObject -> {
+                RemoteSegmentTransferTracker.Stats segmentStats = statObject.getSegmentStats();
+                if (statObject.getShardRouting().primary()) {
+                    assertTrue(
+                        segmentStats.totalUploadsSucceeded == 1
+                            && segmentStats.totalUploadsStarted == segmentStats.totalUploadsSucceeded
+                            && segmentStats.totalUploadsFailed == 0
+                    );
+                } else {
+                    assertTrue(
+                        segmentStats.directoryFileTransferTrackerStats.transferredBytesStarted == 0
+                            && segmentStats.directoryFileTransferTrackerStats.transferredBytesSucceeded == 0
+                    );
+                }
+
+                RemoteTranslogTransferTracker.Stats translogStats = statObject.getTranslogStats();
+                assertZeroTranslogUploadStats(translogStats);
+                assertZeroTranslogDownloadStats(translogStats);
+            });
+        }, 5, TimeUnit.SECONDS);
+    }
+
+    private void indexDocs() {
+        for (int i = 0; i < randomIntBetween(5, 10); i++) {
+            if (randomBoolean()) {
+                flush(INDEX_NAME);
+            } else {
+                refresh(INDEX_NAME);
+            }
+            int numberOfOperations = randomIntBetween(10, 30);
+            indexBulk(INDEX_NAME, numberOfOperations);
+        }
+    }
+
+    private void changeReplicaCountAndEnsureGreen(int replicaCount) {
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareUpdateSettings(INDEX_NAME)
+                .setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, replicaCount))
+        );
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+    }
+
+    private void relocateShard(int shardId, String sourceNode, String destNode) {
+        assertAcked(client().admin().cluster().prepareReroute().add(new MoveAllocationCommand(INDEX_NAME, shardId, sourceNode, destNode)));
+        ensureGreen(INDEX_NAME);
+    }
+
+    private void validateSegmentUploadStats(RemoteSegmentTransferTracker.Stats stats) {
+        assertEquals(0, stats.refreshTimeLagMs);
+        assertEquals(stats.localRefreshNumber, stats.remoteRefreshNumber);
+        assertTrue(stats.uploadBytesStarted > 0);
+        assertEquals(0, stats.uploadBytesFailed);
+        assertTrue(stats.uploadBytesSucceeded > 0);
+        assertTrue(stats.totalUploadsStarted > 0);
+        assertEquals(0, stats.totalUploadsFailed);
+        assertTrue(stats.totalUploadsSucceeded > 0);
+        assertEquals(0, stats.rejectionCount);
+        assertEquals(0, stats.consecutiveFailuresCount);
+        assertEquals(0, stats.bytesLag);
+        assertTrue(stats.uploadBytesMovingAverage > 0);
+        assertTrue(stats.uploadBytesPerSecMovingAverage > 0);
+        assertTrue(stats.uploadTimeMovingAverage > 0);
+    }
+
+    private void validateSegmentDownloadStats(RemoteSegmentTransferTracker.Stats stats) {
+        assertTrue(stats.directoryFileTransferTrackerStats.lastTransferTimestampMs > 0);
+        assertTrue(stats.directoryFileTransferTrackerStats.transferredBytesStarted > 0);
+        assertTrue(stats.directoryFileTransferTrackerStats.transferredBytesSucceeded > 0);
+        assertEquals(stats.directoryFileTransferTrackerStats.transferredBytesFailed, 0);
+        assertTrue(stats.directoryFileTransferTrackerStats.lastSuccessfulTransferInBytes > 0);
+        assertTrue(stats.directoryFileTransferTrackerStats.transferredBytesMovingAverage > 0);
+        assertTrue(stats.directoryFileTransferTrackerStats.transferredBytesPerSecMovingAverage > 0);
+    }
+
+    private void assertNonZeroTranslogUploadStatsNoFailures(RemoteTranslogTransferTracker.Stats stats) {
+        assertTrue(stats.uploadBytesStarted > 0);
+        assertTrue(stats.totalUploadsStarted > 0);
+        assertEquals(0, stats.uploadBytesFailed);
+        assertEquals(0, stats.totalUploadsFailed);
+        assertTrue(stats.uploadBytesSucceeded > 0);
+        assertTrue(stats.totalUploadsSucceeded > 0);
+        assertTrue(stats.totalUploadTimeInMillis > 0);
+        assertTrue(stats.lastSuccessfulUploadTimestamp > 0);
+    }
+
+    private void assertZeroTranslogUploadStats(RemoteTranslogTransferTracker.Stats stats) {
+        assertEquals(0, stats.uploadBytesStarted);
+        assertEquals(0, stats.totalUploadsStarted);
+        assertEquals(0, stats.uploadBytesFailed);
+        assertEquals(0, stats.totalUploadsFailed);
+        assertEquals(0, stats.uploadBytesSucceeded);
+        assertEquals(0, stats.totalUploadsSucceeded);
+        assertEquals(0, stats.totalUploadTimeInMillis);
+        assertEquals(0, stats.lastSuccessfulUploadTimestamp);
+    }
+
+    private void assertNonZeroTranslogDownloadStats(RemoteTranslogTransferTracker.Stats stats) {
+        assertTrue(stats.downloadBytesSucceeded > 0);
+        assertTrue(stats.totalDownloadsSucceeded > 0);
+        // TODO: Need to simulate a delay for this assertion to avoid flakiness
+        // assertTrue(stats.totalDownloadTimeInMillis > 0);
+        assertTrue(stats.lastSuccessfulDownloadTimestamp > 0);
+    }
+
+    private void assertZeroTranslogDownloadStats(RemoteTranslogTransferTracker.Stats stats) {
+        assertEquals(0, stats.downloadBytesSucceeded);
+        assertEquals(0, stats.totalDownloadsSucceeded);
+        assertEquals(0, stats.totalDownloadTimeInMillis);
+        assertEquals(0, stats.lastSuccessfulDownloadTimestamp);
+    }
+
+    // Validate if the shardRouting obtained from cluster state contains the exact same routing object
+    // parameters as obtained from the remote store stats API
+    private void validateShardRouting(ShardRouting routing) {
+        Stream<ShardRouting> currentRoutingTable = getClusterState().routingTable()
+            .getIndicesRouting()
+            .get(INDEX_NAME)
+            .shard(routing.id())
+            .assignedShards()
+            .stream();
+        assertTrue(
+            currentRoutingTable.anyMatch(
+                r -> (r.currentNodeId().equals(routing.currentNodeId())
+                    && r.state().equals(routing.state())
+                    && r.primary() == routing.primary())
+            )
+        );
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/ReplicaToPrimaryPromotionIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/ReplicaToPrimaryPromotionIT.java
new file mode 100644
index 0000000000000..4e3f01b8f257f
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/ReplicaToPrimaryPromotionIT.java
@@ -0,0 +1,184 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import com.carrotsearch.randomizedtesting.RandomizedTest;
+
+import org.opensearch.action.admin.indices.close.CloseIndexResponse;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.test.BackgroundIndexer;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.util.Locale;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class ReplicaToPrimaryPromotionIT extends RemoteStoreBaseIntegTestCase {
+    private int shard_count = 5;
+
+    @Before
+    public void setup() {
+        internalCluster().startClusterManagerOnlyNode();
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder().put(super.indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, shard_count).build();
+    }
+
+    public void testPromoteReplicaToPrimary() throws Exception {
+        internalCluster().startNode();
+        internalCluster().startNode();
+        final String indexName = randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        shard_count = scaledRandomIntBetween(1, 5);
+        createIndex(indexName);
+        int numOfDocs = 0;
+        int numIter = scaledRandomIntBetween(0, 10);
+        for (int i = 0; i < numIter; i++) {
+            final int numOfDoc = scaledRandomIntBetween(0, 200);
+            logger.info("num of docs in iter {} {}", numOfDoc, i);
+            if (numOfDoc > 0) {
+                try (
+                    BackgroundIndexer indexer = new BackgroundIndexer(
+                        indexName,
+                        "_doc",
+                        client(),
+                        numOfDoc,
+                        RandomizedTest.scaledRandomIntBetween(2, 5),
+                        false,
+                        null
+                    )
+                ) {
+                    indexer.setUseAutoGeneratedIDs(true);
+                    indexer.start(numOfDoc);
+                    waitForIndexed(numOfDoc, indexer);
+                    numOfDocs += numOfDoc;
+                    indexer.stopAndAwaitStopped();
+                    if (random().nextBoolean()) {
+                        // 90% refresh + 10% flush
+                        if (random().nextInt(10) != 0) {
+                            refresh(indexName);
+                        } else {
+                            flush(indexName);
+                        }
+                    }
+                }
+            }
+        }
+
+        ensureGreen(indexName);
+
+        // sometimes test with a closed index
+        final IndexMetadata.State indexState = randomFrom(IndexMetadata.State.OPEN, IndexMetadata.State.CLOSE);
+        if (indexState == IndexMetadata.State.CLOSE) {
+            CloseIndexResponse closeIndexResponse = client().admin().indices().prepareClose(indexName).get();
+            assertThat("close index not acked - " + closeIndexResponse, closeIndexResponse.isAcknowledged(), equalTo(true));
+            ensureGreen(indexName);
+        }
+
+        // pick up a data node that contains a random primary shard
+        ClusterState state = client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
+        final int numShards = state.metadata().index(indexName).getNumberOfShards();
+        final ShardRouting primaryShard = state.routingTable().index(indexName).shard(randomIntBetween(0, numShards - 1)).primaryShard();
+        final DiscoveryNode randomNode = state.nodes().resolveNode(primaryShard.currentNodeId());
+
+        // stop the random data node, all remaining shards are promoted to primaries
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(randomNode.getName()));
+        ensureYellowAndNoInitializingShards(indexName);
+
+        state = client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
+        for (IndexShardRoutingTable shardRoutingTable : state.routingTable().index(indexName)) {
+            for (ShardRouting shardRouting : shardRoutingTable.activeShards()) {
+                assertThat(shardRouting + " should be promoted as a primary", shardRouting.primary(), is(true));
+            }
+        }
+
+        if (indexState == IndexMetadata.State.CLOSE) {
+            assertAcked(client().admin().indices().prepareOpen(indexName));
+            ensureYellowAndNoInitializingShards(indexName);
+        }
+        refresh(indexName);
+        assertHitCount(client().prepareSearch(indexName).setSize(0).get(), numOfDocs);
+    }
+
+    public void testFailoverWhileIndexing() throws Exception {
+        internalCluster().startNode();
+        internalCluster().startNode();
+        final String indexName = randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        shard_count = scaledRandomIntBetween(1, 5);
+        createIndex(indexName);
+        ensureGreen(indexName);
+        int docCount = scaledRandomIntBetween(20, 50);
+        final int indexDocAfterFailover = scaledRandomIntBetween(20, 50);
+        AtomicInteger numAutoGenDocs = new AtomicInteger();
+        CountDownLatch latch = new CountDownLatch(1);
+        final AtomicBoolean finished = new AtomicBoolean(false);
+        Thread indexingThread = new Thread(() -> {
+            int docsAfterFailover = 0;
+            while (finished.get() == false && numAutoGenDocs.get() < docCount) {
+                IndexResponse indexResponse = internalCluster().clusterManagerClient()
+                    .prepareIndex(indexName)
+                    .setSource("field", numAutoGenDocs.get())
+                    .get();
+
+                if (indexResponse.status() == RestStatus.CREATED || indexResponse.status() == RestStatus.OK) {
+                    numAutoGenDocs.incrementAndGet();
+                    if (numAutoGenDocs.get() == docCount / 2) {
+                        if (random().nextInt(3) == 0) {
+                            refresh(indexName);
+                        } else if (random().nextInt(2) == 0) {
+                            flush(indexName);
+                        }
+                        // Node is killed on this
+                        latch.countDown();
+                    } else if (numAutoGenDocs.get() > docCount / 2) {
+                        docsAfterFailover++;
+                        if (docsAfterFailover == indexDocAfterFailover) {
+                            finished.set(true);
+                        }
+                    }
+                }
+            }
+            logger.debug("Done indexing");
+        });
+        indexingThread.start();
+        latch.await();
+
+        ClusterState state = client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
+        final int numShards = state.metadata().index(indexName).getNumberOfShards();
+        final ShardRouting primaryShard = state.routingTable().index(indexName).shard(randomIntBetween(0, numShards - 1)).primaryShard();
+        final DiscoveryNode randomNode = state.nodes().resolveNode(primaryShard.currentNodeId());
+
+        // stop the random data node, all remaining shards are promoted to primaries
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(randomNode.getName()));
+        ensureYellowAndNoInitializingShards(indexName);
+        indexingThread.join();
+        refresh(indexName);
+        assertHitCount(
+            client(internalCluster().getClusterManagerName()).prepareSearch(indexName).setSize(0).setTrackTotalHits(true).get(),
+            numAutoGenDocs.get()
+        );
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationUsingRemoteStoreIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationUsingRemoteStoreIT.java
new file mode 100644
index 0000000000000..23864c35ad154
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationUsingRemoteStoreIT.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.indices.replication.SegmentReplicationIT;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+
+/**
+ * This class runs Segment Replication Integ test suite with remote store enabled.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationUsingRemoteStoreIT extends SegmentReplicationIT {
+
+    private static final String REPOSITORY_NAME = "test-remote-store-repo";
+    protected Path absolutePath;
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        if (absolutePath == null) {
+            absolutePath = randomRepoPath().toAbsolutePath();
+        }
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, absolutePath))
+            .build();
+    }
+
+    protected boolean segmentReplicationWithRemoteEnabled() {
+        return true;
+    }
+
+    @Before
+    public void setup() {
+        internalCluster().startClusterManagerOnlyNode();
+    }
+
+    @After
+    public void teardown() {
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_NAME).get();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationWithRemoteStorePressureIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationWithRemoteStorePressureIT.java
new file mode 100644
index 0000000000000..6cfc76b7e3223
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/SegmentReplicationWithRemoteStorePressureIT.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.SegmentReplicationPressureIT;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+
+/**
+ * This class executes the SegmentReplicationPressureIT suite with remote store integration enabled.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationWithRemoteStorePressureIT extends SegmentReplicationPressureIT {
+
+    private static final String REPOSITORY_NAME = "test-remote-store-repo";
+    protected Path absolutePath;
+
+    @Override
+    protected boolean segmentReplicationWithRemoteEnabled() {
+        return true;
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, absolutePath))
+            .build();
+    }
+
+    @Before
+    public void setup() {
+        absolutePath = randomRepoPath().toAbsolutePath();
+        internalCluster().startClusterManagerOnlyNode();
+    }
+
+    @After
+    public void teardown() {
+        clusterAdmin().prepareCleanupRepository(REPOSITORY_NAME).get();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartFileCorruptionIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartFileCorruptionIT.java
new file mode 100644
index 0000000000000..7112b266840ac
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartFileCorruptionIT.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart;
+
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexModule;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.remotestore.RemoteStoreBaseIntegTestCase;
+import org.opensearch.remotestore.multipart.mocks.MockFsRepositoryPlugin;
+
+import java.util.Collection;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class RemoteStoreMultipartFileCorruptionIT extends RemoteStoreBaseIntegTestCase {
+
+    private static final String INDEX_NAME = "remote-store-test-idx-1";
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Stream.concat(super.nodePlugins().stream(), Stream.of(MockFsRepositoryPlugin.class)).collect(Collectors.toList());
+    }
+
+    protected Settings remoteStoreIndexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put("index.refresh_interval", "300s")
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    public void testLocalFileCorruptionDuringUpload() {
+        internalCluster().startDataOnlyNodes(1);
+        createIndex(INDEX_NAME, remoteStoreIndexSettings());
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        indexSingleDoc(INDEX_NAME);
+
+        client().admin()
+            .indices()
+            .prepareRefresh(INDEX_NAME)
+            .setIndicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_HIDDEN_FORBID_CLOSED)
+            .execute()
+            .actionGet();
+
+        // ensuring red cluster meaning shard has failed and is unassigned
+        ensureRed(INDEX_NAME);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartIT.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartIT.java
new file mode 100644
index 0000000000000..3dfde6f472525
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/RemoteStoreMultipartIT.java
@@ -0,0 +1,155 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart;
+
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.remotestore.RemoteStoreIT;
+import org.opensearch.remotestore.multipart.mocks.MockFsRepositoryPlugin;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.junit.Before;
+
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.Locale;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+
+public class RemoteStoreMultipartIT extends RemoteStoreIT {
+
+    Path repositoryLocation;
+    boolean compress;
+    boolean overrideBuildRepositoryMetadata;
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Stream.concat(super.nodePlugins().stream(), Stream.of(MockFsRepositoryPlugin.class)).collect(Collectors.toList());
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(
+                remoteStoreClusterSettings(
+                    REPOSITORY_NAME,
+                    segmentRepoPath,
+                    MockFsRepositoryPlugin.TYPE,
+                    REPOSITORY_2_NAME,
+                    translogRepoPath,
+                    MockFsRepositoryPlugin.TYPE
+                )
+            )
+            .build();
+    }
+
+    @Before
+    public void setup() {
+        clusterSettingsSuppliedByTest = true;
+        overrideBuildRepositoryMetadata = false;
+        repositoryLocation = randomRepoPath();
+        compress = randomBoolean();
+    }
+
+    @Override
+    public RepositoryMetadata buildRepositoryMetadata(DiscoveryNode node, String name) {
+        if (overrideBuildRepositoryMetadata) {
+            Map<String, String> nodeAttributes = node.getAttributes();
+            String type = nodeAttributes.get(String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, name));
+
+            String settingsAttributeKeyPrefix = String.format(
+                Locale.getDefault(),
+                REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+                name
+            );
+            Map<String, String> settingsMap = node.getAttributes()
+                .keySet()
+                .stream()
+                .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+                .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix, ""), key -> node.getAttributes().get(key)));
+
+            Settings.Builder settings = Settings.builder();
+            settingsMap.entrySet().forEach(entry -> settings.put(entry.getKey(), entry.getValue()));
+            settings.put(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING.getKey(), true);
+
+            if (name.equals(REPOSITORY_NAME)) {
+                settings.put("location", repositoryLocation)
+                    .put("compress", compress)
+                    .put("max_remote_upload_bytes_per_sec", "1kb")
+                    .put("chunk_size", 100, ByteSizeUnit.BYTES);
+                return new RepositoryMetadata(name, MockFsRepositoryPlugin.TYPE, settings.build());
+            }
+
+            return new RepositoryMetadata(name, type, settings.build());
+        } else {
+            return super.buildRepositoryMetadata(node, name);
+        }
+
+    }
+
+    public void testRateLimitedRemoteUploads() throws Exception {
+        clusterSettingsSuppliedByTest = true;
+        overrideBuildRepositoryMetadata = true;
+        Settings.Builder clusterSettings = Settings.builder()
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, repositoryLocation, REPOSITORY_2_NAME, repositoryLocation));
+        clusterSettings.put(
+            String.format(Locale.getDefault(), "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, REPOSITORY_NAME),
+            MockFsRepositoryPlugin.TYPE
+        );
+        internalCluster().startNode(clusterSettings.build());
+        Client client = client();
+        logger.info("-->  updating repository");
+        assertAcked(
+            client.admin()
+                .cluster()
+                .preparePutRepository(REPOSITORY_NAME)
+                .setType(MockFsRepositoryPlugin.TYPE)
+                .setSettings(
+                    Settings.builder()
+                        .put("location", repositoryLocation)
+                        .put("compress", compress)
+                        .put("max_remote_upload_bytes_per_sec", "1kb")
+                        .put("chunk_size", 100, ByteSizeUnit.BYTES)
+                )
+        );
+
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureGreen();
+
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 10; i++) {
+            index(INDEX_NAME, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+        // check if throttling is active
+        assertBusy(() -> {
+            long uploadPauseTime = 0L;
+            for (RepositoriesService repositoriesService : internalCluster().getDataNodeInstances(RepositoriesService.class)) {
+                uploadPauseTime += repositoriesService.repository(REPOSITORY_NAME).getRemoteUploadThrottleTimeInNanos();
+            }
+            assertThat(uploadPauseTime, greaterThan(TimeValue.timeValueSeconds(randomIntBetween(5, 10)).nanos()));
+        }, 30, TimeUnit.SECONDS);
+
+        assertThat(client.prepareSearch(INDEX_NAME).setSize(0).get().getHits().getTotalHits().value, equalTo(10L));
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsAsyncBlobContainer.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsAsyncBlobContainer.java
new file mode 100644
index 0000000000000..36987ac2d4991
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsAsyncBlobContainer.java
@@ -0,0 +1,149 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart.mocks;
+
+import org.apache.lucene.index.CorruptIndexException;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.fs.FsBlobContainer;
+import org.opensearch.common.blobstore.fs.FsBlobStore;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class MockFsAsyncBlobContainer extends FsBlobContainer implements AsyncMultiStreamBlobContainer {
+
+    private static final int TRANSFER_TIMEOUT_MILLIS = 30000;
+
+    private final boolean triggerDataIntegrityFailure;
+
+    public MockFsAsyncBlobContainer(FsBlobStore blobStore, BlobPath blobPath, Path path, boolean triggerDataIntegrityFailure) {
+        super(blobStore, blobPath, path);
+        this.triggerDataIntegrityFailure = triggerDataIntegrityFailure;
+    }
+
+    @Override
+    public void asyncBlobUpload(WriteContext writeContext, ActionListener<Void> completionListener) throws IOException {
+
+        int nParts = 10;
+        long partSize = writeContext.getFileSize() / nParts;
+        StreamContext streamContext = writeContext.getStreamProvider(partSize);
+        final Path file = path.resolve(writeContext.getFileName());
+        byte[] buffer = new byte[(int) writeContext.getFileSize()];
+        AtomicLong totalContentRead = new AtomicLong();
+        CountDownLatch latch = new CountDownLatch(streamContext.getNumberOfParts());
+        for (int partIdx = 0; partIdx < streamContext.getNumberOfParts(); partIdx++) {
+            int finalPartIdx = partIdx;
+            Thread thread = new Thread(() -> {
+                try {
+                    InputStreamContainer inputStreamContainer = streamContext.provideStream(finalPartIdx);
+                    InputStream inputStream = inputStreamContainer.getInputStream();
+                    long remainingContentLength = inputStreamContainer.getContentLength();
+                    long offset = partSize * finalPartIdx;
+                    while (remainingContentLength > 0) {
+                        int readContentLength = inputStream.read(buffer, (int) offset, (int) remainingContentLength);
+                        totalContentRead.addAndGet(readContentLength);
+                        remainingContentLength -= readContentLength;
+                        offset += readContentLength;
+                    }
+                    inputStream.close();
+                } catch (IOException e) {
+                    completionListener.onFailure(e);
+                } finally {
+                    latch.countDown();
+                }
+            });
+            thread.start();
+        }
+        try {
+            if (!latch.await(TRANSFER_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)) {
+                throw new IOException("Timed out waiting for file transfer to complete for " + writeContext.getFileName());
+            }
+        } catch (InterruptedException e) {
+            throw new IOException("Await interrupted on CountDownLatch, transfer failed for " + writeContext.getFileName());
+        }
+        try (OutputStream outputStream = Files.newOutputStream(file, StandardOpenOption.CREATE_NEW)) {
+            outputStream.write(buffer);
+        }
+        if (writeContext.getFileSize() != totalContentRead.get()) {
+            throw new IOException(
+                "Incorrect content length read for file "
+                    + writeContext.getFileName()
+                    + ", actual file size: "
+                    + writeContext.getFileSize()
+                    + ", bytes read: "
+                    + totalContentRead.get()
+            );
+        }
+
+        try {
+            // bulks need to succeed for segment files to be generated
+            if (isSegmentFile(writeContext.getFileName()) && triggerDataIntegrityFailure) {
+                completionListener.onFailure(
+                    new RuntimeException(
+                        new CorruptIndexException(
+                            "Data integrity check failure for file: " + writeContext.getFileName(),
+                            writeContext.getFileName()
+                        )
+                    )
+                );
+            } else {
+                writeContext.getUploadFinalizer().accept(true);
+                completionListener.onResponse(null);
+            }
+        } catch (Exception e) {
+            completionListener.onFailure(e);
+        }
+
+    }
+
+    @Override
+    public void readBlobAsync(String blobName, ActionListener<ReadContext> listener) {
+        new Thread(() -> {
+            try {
+                long contentLength = listBlobs().get(blobName).length();
+                long partSize = contentLength / 10;
+                int numberOfParts = (int) ((contentLength % partSize) == 0 ? contentLength / partSize : (contentLength / partSize) + 1);
+                List<ReadContext.StreamPartCreator> blobPartStreams = new ArrayList<>();
+                for (int partNumber = 0; partNumber < numberOfParts; partNumber++) {
+                    long offset = partNumber * partSize;
+                    InputStreamContainer blobPartStream = new InputStreamContainer(readBlob(blobName, offset, partSize), partSize, offset);
+                    blobPartStreams.add(() -> CompletableFuture.completedFuture(blobPartStream));
+                }
+                ReadContext blobReadContext = new ReadContext(contentLength, blobPartStreams, null);
+                listener.onResponse(blobReadContext);
+            } catch (Exception e) {
+                listener.onFailure(e);
+            }
+        }).start();
+    }
+
+    public boolean remoteIntegrityCheckSupported() {
+        return true;
+    }
+
+    private boolean isSegmentFile(String filename) {
+        return !filename.endsWith(".tlog") && !filename.endsWith(".ckp");
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsBlobStore.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsBlobStore.java
new file mode 100644
index 0000000000000..77b0cac922014
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsBlobStore.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart.mocks;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.fs.FsBlobStore;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+public class MockFsBlobStore extends FsBlobStore {
+
+    private final boolean triggerDataIntegrityFailure;
+
+    public MockFsBlobStore(int bufferSizeInBytes, Path path, boolean readonly, boolean triggerDataIntegrityFailure) throws IOException {
+        super(bufferSizeInBytes, path, readonly);
+        this.triggerDataIntegrityFailure = triggerDataIntegrityFailure;
+    }
+
+    @Override
+    public BlobContainer blobContainer(BlobPath path) {
+        try {
+            return new MockFsAsyncBlobContainer(this, path, buildAndCreate(path), triggerDataIntegrityFailure);
+        } catch (IOException ex) {
+            throw new OpenSearchException("failed to create blob container", ex);
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepository.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepository.java
new file mode 100644
index 0000000000000..15a9853477081
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepository.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart.mocks;
+
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.fs.FsBlobStore;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.repositories.fs.FsRepository;
+
+public class MockFsRepository extends FsRepository {
+
+    public static Setting<Boolean> TRIGGER_DATA_INTEGRITY_FAILURE = Setting.boolSetting(
+        "mock_fs_repository.trigger_data_integrity_failure",
+        false
+    );
+
+    private final boolean triggerDataIntegrityFailure;
+
+    public MockFsRepository(
+        RepositoryMetadata metadata,
+        Environment environment,
+        NamedXContentRegistry namedXContentRegistry,
+        ClusterService clusterService,
+        RecoverySettings recoverySettings
+    ) {
+        super(metadata, environment, namedXContentRegistry, clusterService, recoverySettings);
+        triggerDataIntegrityFailure = TRIGGER_DATA_INTEGRITY_FAILURE.get(metadata.settings());
+    }
+
+    @Override
+    protected BlobStore createBlobStore() throws Exception {
+        FsBlobStore fsBlobStore = (FsBlobStore) super.createBlobStore();
+        return new MockFsBlobStore(fsBlobStore.bufferSizeInBytes(), fsBlobStore.path(), isReadOnly(), triggerDataIntegrityFailure);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepositoryPlugin.java b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepositoryPlugin.java
new file mode 100644
index 0000000000000..ffd53adf4e29e
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/remotestore/multipart/mocks/MockFsRepositoryPlugin.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotestore.multipart.mocks;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.RepositoryPlugin;
+import org.opensearch.repositories.Repository;
+
+import java.util.Collections;
+import java.util.Map;
+
+public class MockFsRepositoryPlugin extends Plugin implements RepositoryPlugin {
+
+    public static final String TYPE = "fs_multipart_repository";
+
+    @Override
+    public Map<String, Repository.Factory> getRepositories(
+        Environment env,
+        NamedXContentRegistry namedXContentRegistry,
+        ClusterService clusterService,
+        RecoverySettings recoverySettings
+    ) {
+        return Collections.singletonMap(
+            "fs_multipart_repository",
+            metadata -> new MockFsRepository(metadata, env, namedXContentRegistry, clusterService, recoverySettings)
+        );
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/repositories/RepositoriesServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/repositories/RepositoriesServiceIT.java
index 78cf55e2f223c..b8415f4b41815 100644
--- a/server/src/internalClusterTest/java/org/opensearch/repositories/RepositoriesServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/repositories/RepositoriesServiceIT.java
@@ -39,8 +39,8 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.snapshots.mockstore.MockRepository;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -65,7 +65,9 @@ public void testUpdateRepository() {
         final String repositoryName = "test-repo";
 
         final Client client = client();
-        final RepositoriesService repositoriesService = cluster.getDataOrMasterNodeInstances(RepositoriesService.class).iterator().next();
+        final RepositoriesService repositoriesService = cluster.getDataOrClusterManagerNodeInstances(RepositoriesService.class)
+            .iterator()
+            .next();
 
         final Settings.Builder repoSettings = Settings.builder().put("location", randomRepoPath());
 
@@ -106,4 +108,16 @@ public void testUpdateRepository() {
         final Repository updatedRepository = repositoriesService.repository(repositoryName);
         assertThat(updatedRepository, updated ? not(sameInstance(originalRepository)) : sameInstance(originalRepository));
     }
+
+    public void testSystemRepositoryCantBeCreated() {
+        internalCluster();
+        final String repositoryName = "test-repo";
+        final Client client = client();
+        final Settings.Builder repoSettings = Settings.builder().put("system_repository", true).put("location", randomRepoPath());
+
+        assertThrows(
+            RepositoryException.class,
+            () -> client.admin().cluster().preparePutRepository(repositoryName).setType(FsRepository.TYPE).setSettings(repoSettings).get()
+        );
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryCleanupIT.java b/server/src/internalClusterTest/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryCleanupIT.java
index 7208a608e1ea1..29aab140231c7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryCleanupIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryCleanupIT.java
@@ -51,12 +51,12 @@
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class BlobStoreRepositoryCleanupIT extends AbstractSnapshotIntegTestCase {
 
-    public void testMasterFailoverDuringCleanup() throws Exception {
+    public void testClusterManagerFailoverDuringCleanup() throws Exception {
         startBlockedCleanup("test-repo");
 
-        final int nodeCount = internalCluster().numDataAndMasterNodes();
-        logger.info("-->  stopping master node");
-        internalCluster().stopCurrentMasterNode();
+        final int nodeCount = internalCluster().numDataAndClusterManagerNodes();
+        logger.info("-->  stopping cluster-manager node");
+        internalCluster().stopCurrentClusterManagerNode();
 
         ensureStableCluster(nodeCount - 1);
 
@@ -67,7 +67,7 @@ public void testMasterFailoverDuringCleanup() throws Exception {
     }
 
     public void testRepeatCleanupsDontRemove() throws Exception {
-        final String masterNode = startBlockedCleanup("test-repo");
+        final String clusterManagerNode = startBlockedCleanup("test-repo");
 
         logger.info("-->  sending another cleanup");
         assertFutureThrows(client().admin().cluster().prepareCleanupRepository("test-repo").execute(), IllegalStateException.class);
@@ -81,8 +81,8 @@ public void testRepeatCleanupsDontRemove() throws Exception {
             .custom(RepositoryCleanupInProgress.TYPE);
         assertTrue(cleanup.hasCleanupInProgress());
 
-        logger.info("-->  unblocking master node");
-        unblockNode("test-repo", masterNode);
+        logger.info("-->  unblocking cluster-manager node");
+        unblockNode("test-repo", clusterManagerNode);
 
         logger.info("-->  wait for cleanup to finish and disappear from cluster state");
         awaitClusterState(
@@ -91,8 +91,8 @@ public void testRepeatCleanupsDontRemove() throws Exception {
     }
 
     private String startBlockedCleanup(String repoName) throws Exception {
-        logger.info("-->  starting two master nodes and one data node");
-        internalCluster().startMasterOnlyNodes(2);
+        logger.info("-->  starting two cluster-manager nodes and one data node");
+        internalCluster().startClusterManagerOnlyNodes(2);
         internalCluster().startDataOnlyNodes(1);
 
         createRepository(repoName, "mock");
@@ -100,7 +100,10 @@ private String startBlockedCleanup(String repoName) throws Exception {
         logger.info("-->  snapshot");
         client().admin().cluster().prepareCreateSnapshot(repoName, "test-snap").setWaitForCompletion(true).get();
 
-        final RepositoriesService service = internalCluster().getInstance(RepositoriesService.class, internalCluster().getMasterName());
+        final RepositoriesService service = internalCluster().getInstance(
+            RepositoriesService.class,
+            internalCluster().getClusterManagerName()
+        );
         final BlobStoreRepository repository = (BlobStoreRepository) service.repository(repoName);
 
         logger.info("--> creating a garbage data blob");
@@ -117,17 +120,17 @@ private String startBlockedCleanup(String repoName) throws Exception {
             );
         garbageFuture.get();
 
-        final String masterNode = blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
+        final String clusterManagerNode = blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
 
         logger.info("--> starting repository cleanup");
         client().admin().cluster().prepareCleanupRepository(repoName).execute();
 
-        logger.info("--> waiting for block to kick in on " + masterNode);
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(60));
+        logger.info("--> waiting for block to kick in on " + clusterManagerNode);
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(60));
         awaitClusterState(
             state -> state.custom(RepositoryCleanupInProgress.TYPE, RepositoryCleanupInProgress.EMPTY).hasCleanupInProgress()
         );
-        return masterNode;
+        return clusterManagerNode;
     }
 
     public void testCleanupOldIndexN() throws ExecutionException, InterruptedException {
@@ -146,7 +149,10 @@ public void testCleanupOldIndexN() throws ExecutionException, InterruptedExcepti
             assertThat(createSnapshotResponse.getSnapshotInfo().state(), is(SnapshotState.SUCCESS));
         }
 
-        final RepositoriesService service = internalCluster().getInstance(RepositoriesService.class, internalCluster().getMasterName());
+        final RepositoriesService service = internalCluster().getInstance(
+            RepositoriesService.class,
+            internalCluster().getClusterManagerName()
+        );
         final BlobStoreRepository repository = (BlobStoreRepository) service.repository(repoName);
 
         logger.info("--> write two outdated index-N blobs");
diff --git a/server/src/internalClusterTest/java/org/opensearch/repositories/fs/FsBlobStoreRepositoryIT.java b/server/src/internalClusterTest/java/org/opensearch/repositories/fs/FsBlobStoreRepositoryIT.java
index 75deb731881ec..9057ef900efbd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/repositories/fs/FsBlobStoreRepositoryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/repositories/fs/FsBlobStoreRepositoryIT.java
@@ -35,11 +35,11 @@
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.fs.FsBlobStore;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.repositories.blobstore.OpenSearchBlobStoreRepositoryIntegTestCase;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/routing/AliasRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/routing/AliasRoutingIT.java
index 274133c2c8239..299c2da21c222 100644
--- a/server/src/internalClusterTest/java/org/opensearch/routing/AliasRoutingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/routing/AliasRoutingIT.java
@@ -44,7 +44,6 @@
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.equalTo;
 
 /**
diff --git a/server/src/internalClusterTest/java/org/opensearch/routing/PartitionedRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/routing/PartitionedRoutingIT.java
index a64e857f089f0..64df858a18c9d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/routing/PartitionedRoutingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/routing/PartitionedRoutingIT.java
@@ -38,13 +38,14 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.OpenSearchIntegTestCase;
-import org.mockito.internal.util.collections.Sets;
 
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
+import org.mockito.internal.util.collections.Sets;
+
 public class PartitionedRoutingIT extends OpenSearchIntegTestCase {
 
     public void testVariousPartitionSizes() throws Exception {
@@ -133,7 +134,7 @@ public void testShrinking() throws Exception {
                                 .nodes()
                                 .getDataNodes()
                                 .values()
-                                .toArray(DiscoveryNode.class)[0].getName()
+                                .toArray(new DiscoveryNode[0])[0].getName()
                         )
                         .put("index.blocks.write", true)
                 )
diff --git a/server/src/internalClusterTest/java/org/opensearch/routing/SimpleRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/routing/SimpleRoutingIT.java
index 8909b9deece9b..80e82fa387c96 100644
--- a/server/src/internalClusterTest/java/org/opensearch/routing/SimpleRoutingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/routing/SimpleRoutingIT.java
@@ -54,9 +54,9 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import static org.hamcrest.Matchers.containsString;
diff --git a/server/src/internalClusterTest/java/org/opensearch/script/ScriptCacheIT.java b/server/src/internalClusterTest/java/org/opensearch/script/ScriptCacheIT.java
index b4823bb482bfa..2fbaf4ea5a4d3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/script/ScriptCacheIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/script/ScriptCacheIT.java
@@ -8,22 +8,26 @@
 
 package org.opensearch.script;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.mapper.MockFieldFilterPlugin;
 import org.opensearch.node.NodeMocksPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.MockSearchService;
 import org.opensearch.test.MockHttpTransport;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
 import org.opensearch.test.store.MockFSIndexStore;
 import org.opensearch.test.transport.MockTransportService;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -31,9 +35,26 @@
 import java.util.concurrent.ExecutionException;
 import java.util.function.Function;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.apache.logging.log4j.core.util.Throwables.getRootCause;
 
-public class ScriptCacheIT extends OpenSearchIntegTestCase {
+public class ScriptCacheIT extends ParameterizedOpenSearchIntegTestCase {
+    public ScriptCacheIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     protected Settings nodeSettings(int nodeOrdinal) {
         Settings.Builder builder = Settings.builder()
diff --git a/server/src/internalClusterTest/java/org/opensearch/script/StoredScriptsIT.java b/server/src/internalClusterTest/java/org/opensearch/script/StoredScriptsIT.java
index 0d3a7154559cb..71b48a8357e80 100644
--- a/server/src/internalClusterTest/java/org/opensearch/script/StoredScriptsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/script/StoredScriptsIT.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
@@ -69,7 +69,7 @@ public void testBasics() {
                 .cluster()
                 .preparePutStoredScript()
                 .setId("foobar")
-                .setContent(new BytesArray("{\"script\": {\"lang\": \"" + LANG + "\", \"source\": \"1\"} }"), XContentType.JSON)
+                .setContent(new BytesArray("{\"script\": {\"lang\": \"" + LANG + "\", \"source\": \"1\"} }"), MediaTypeRegistry.JSON)
         );
         String script = client().admin().cluster().prepareGetStoredScript("foobar").get().getSource().getSource();
         assertNotNull(script);
@@ -81,7 +81,12 @@ public void testBasics() {
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> client().admin().cluster().preparePutStoredScript().setId("id#").setContent(new BytesArray("{}"), XContentType.JSON).get()
+            () -> client().admin()
+                .cluster()
+                .preparePutStoredScript()
+                .setId("id#")
+                .setContent(new BytesArray("{}"), MediaTypeRegistry.JSON)
+                .get()
         );
         assertEquals("Validation Failed: 1: id cannot contain '#' for stored script;", e.getMessage());
     }
@@ -95,7 +100,7 @@ public void testMaxScriptSize() {
                 .setId("foobar")
                 .setContent(
                     new BytesArray("{\"script\": { \"lang\": \"" + LANG + "\"," + " \"source\":\"0123456789abcdef\"} }"),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
                 .get()
         );
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/SearchCancellationIT.java b/server/src/internalClusterTest/java/org/opensearch/search/SearchCancellationIT.java
index da5698918cf99..18b4625761c51 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/SearchCancellationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/SearchCancellationIT.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.search;
 
-import org.apache.logging.log4j.LogManager;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
-import org.junit.After;
+import org.apache.logging.log4j.LogManager;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.action.bulk.BulkRequestBuilder;
@@ -48,28 +47,33 @@
 import org.opensearch.action.search.SearchScrollAction;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.lookup.LeafFieldsLookup;
-import org.opensearch.tasks.TaskCancelledException;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.transport.TransportException;
+import org.junit.After;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
@@ -77,6 +81,7 @@
 import static org.opensearch.action.search.TransportSearchAction.SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY;
 import static org.opensearch.index.query.QueryBuilders.scriptQuery;
 import static org.opensearch.search.SearchCancellationIT.ScriptedBlockPlugin.SCRIPT_NAME;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.SearchService.NO_TIMEOUT;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -86,7 +91,28 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class SearchCancellationIT extends OpenSearchIntegTestCase {
+public class SearchCancellationIT extends ParameterizedOpenSearchIntegTestCase {
+
+    private TimeValue requestCancellationTimeout = TimeValue.timeValueSeconds(1);
+    private TimeValue clusterCancellationTimeout = TimeValue.timeValueMillis(1500);
+    private TimeValue keepAlive = TimeValue.timeValueSeconds(5);
+
+    public SearchCancellationIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -225,7 +251,7 @@ public void testCancellationDuringQueryPhase() throws Exception {
         awaitForBlock(plugins);
         cancelSearch(SearchAction.NAME);
         disableBlocks(plugins);
-        logger.info("Segments {}", Strings.toString(client().admin().indices().prepareSegments("test").get()));
+        logger.info("Segments {}", Strings.toString(MediaTypeRegistry.JSON, client().admin().indices().prepareSegments("test").get()));
         ensureSearchWasCancelled(searchResponse);
     }
 
@@ -233,15 +259,13 @@ public void testCancellationDuringQueryPhaseUsingRequestParameter() throws Excep
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
 
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
-            .setCancelAfterTimeInterval(cancellationTimeout)
+            .setCancelAfterTimeInterval(requestCancellationTimeout)
             .setAllowPartialSearchResults(randomBoolean())
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())))
             .execute();
         awaitForBlock(plugins);
-        // sleep for cancellation timeout to ensure scheduled cancellation task is actually executed
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(requestCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         ensureSearchWasCancelled(searchResponse);
@@ -251,19 +275,19 @@ public void testCancellationDuringQueryPhaseUsingClusterSetting() throws Excepti
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
 
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         client().admin()
             .cluster()
             .prepareUpdateSettings()
-            .setPersistentSettings(Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, cancellationTimeout).build())
+            .setPersistentSettings(
+                Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, clusterCancellationTimeout).build()
+            )
             .get();
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
             .setAllowPartialSearchResults(randomBoolean())
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())))
             .execute();
         awaitForBlock(plugins);
-        // sleep for cluster cancellation timeout to ensure scheduled cancellation task is actually executed
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(clusterCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         ensureSearchWasCancelled(searchResponse);
@@ -281,21 +305,19 @@ public void testCancellationDuringFetchPhase() throws Exception {
         awaitForBlock(plugins);
         cancelSearch(SearchAction.NAME);
         disableBlocks(plugins);
-        logger.info("Segments {}", Strings.toString(client().admin().indices().prepareSegments("test").get()));
+        logger.info("Segments {}", Strings.toString(MediaTypeRegistry.JSON, client().admin().indices().prepareSegments("test").get()));
         ensureSearchWasCancelled(searchResponse);
     }
 
     public void testCancellationDuringFetchPhaseUsingRequestParameter() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
-            .setCancelAfterTimeInterval(cancellationTimeout)
+            .setCancelAfterTimeInterval(requestCancellationTimeout)
             .addScriptField("test_field", new Script(ScriptType.INLINE, "mockscript", SCRIPT_NAME, Collections.emptyMap()))
             .execute();
         awaitForBlock(plugins);
-        // sleep for request cancellation timeout to ensure scheduled cancellation task is actually executed
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(requestCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         ensureSearchWasCancelled(searchResponse);
@@ -307,7 +329,7 @@ public void testCancellationOfScrollSearches() throws Exception {
 
         logger.info("Executing search");
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
-            .setScroll(TimeValue.timeValueSeconds(10))
+            .setScroll(keepAlive)
             .setSize(5)
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", SCRIPT_NAME, Collections.emptyMap())))
             .execute();
@@ -326,16 +348,16 @@ public void testCancellationOfScrollSearches() throws Exception {
     public void testCancellationOfFirstScrollSearchRequestUsingRequestParameter() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
-            .setScroll(TimeValue.timeValueSeconds(10))
-            .setCancelAfterTimeInterval(cancellationTimeout)
+            .setScroll(keepAlive)
+            .setCancelAfterTimeInterval(requestCancellationTimeout)
             .setSize(5)
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", SCRIPT_NAME, Collections.emptyMap())))
             .execute();
 
         awaitForBlock(plugins);
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(requestCancellationTimeout.getMillis());
+        // unblock the search thread
         disableBlocks(plugins);
         SearchResponse response = ensureSearchWasCancelled(searchResponse);
         if (response != null) {
@@ -354,7 +376,6 @@ public void testCancellationOfScrollSearchesOnFollowupRequests() throws Exceptio
         disableBlocks(plugins);
 
         logger.info("Executing search");
-        TimeValue keepAlive = TimeValue.timeValueSeconds(5);
         SearchResponse searchResponse = client().prepareSearch("test")
             .setScroll(keepAlive)
             .setSize(2)
@@ -394,11 +415,9 @@ public void testNoCancellationOfScrollSearchOnFollowUpRequest() throws Exception
 
         // Disable block so the first request would pass
         disableBlocks(plugins);
-        TimeValue keepAlive = TimeValue.timeValueSeconds(5);
-        TimeValue cancellationTimeout = TimeValue.timeValueSeconds(2);
         SearchResponse searchResponse = client().prepareSearch("test")
             .setScroll(keepAlive)
-            .setCancelAfterTimeInterval(cancellationTimeout)
+            .setCancelAfterTimeInterval(requestCancellationTimeout)
             .setSize(2)
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())))
             .get();
@@ -418,8 +437,8 @@ public void testNoCancellationOfScrollSearchOnFollowUpRequest() throws Exception
             .execute();
 
         awaitForBlock(plugins);
-        // sleep for cancellation timeout to ensure there is no scheduled task for cancellation
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(requestCancellationTimeout.getMillis());
+        // unblock the search thread
         disableBlocks(plugins);
 
         // wait for response and ensure there is no failure
@@ -432,11 +451,12 @@ public void testNoCancellationOfScrollSearchOnFollowUpRequest() throws Exception
     public void testDisableCancellationAtRequestLevel() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         client().admin()
             .cluster()
             .prepareUpdateSettings()
-            .setPersistentSettings(Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, cancellationTimeout).build())
+            .setPersistentSettings(
+                Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, clusterCancellationTimeout).build()
+            )
             .get();
         ActionFuture<SearchResponse> searchResponse = client().prepareSearch("test")
             .setAllowPartialSearchResults(randomBoolean())
@@ -444,8 +464,7 @@ public void testDisableCancellationAtRequestLevel() throws Exception {
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())))
             .execute();
         awaitForBlock(plugins);
-        // sleep for cancellation timeout to ensure there is no scheduled task for cancellation
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(clusterCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         // ensure search was successful since cancellation was disabled at request level
@@ -455,7 +474,6 @@ public void testDisableCancellationAtRequestLevel() throws Exception {
     public void testDisableCancellationAtClusterLevel() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         client().admin()
             .cluster()
             .prepareUpdateSettings()
@@ -466,8 +484,7 @@ public void testDisableCancellationAtClusterLevel() throws Exception {
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap())))
             .execute();
         awaitForBlock(plugins);
-        // sleep for cancellation timeout to ensure there is no scheduled task for cancellation
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(clusterCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         // ensure search was successful since cancellation was disabled at request level
@@ -501,11 +518,12 @@ public void testCancelMultiSearch() throws Exception {
     public void testMSearchChildRequestCancellationWithClusterLevelTimeout() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue cancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
         client().admin()
             .cluster()
             .prepareUpdateSettings()
-            .setPersistentSettings(Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, cancellationTimeout).build())
+            .setPersistentSettings(
+                Settings.builder().put(SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING_KEY, clusterCancellationTimeout).build()
+            )
             .get();
         ActionFuture<MultiSearchResponse> mSearchResponse = client().prepareMultiSearch()
             .setMaxConcurrentSearchRequests(2)
@@ -526,8 +544,7 @@ public void testMSearchChildRequestCancellationWithClusterLevelTimeout() throws
             )
             .execute();
         awaitForBlock(plugins);
-        // sleep for cluster cancellation timeout to ensure scheduled cancellation task is actually executed
-        Thread.sleep(cancellationTimeout.getMillis());
+        sleepForAtLeast(clusterCancellationTimeout.getMillis());
         // unblock the search thread
         disableBlocks(plugins);
         // both child requests are expected to fail
@@ -544,8 +561,6 @@ public void testMSearchChildRequestCancellationWithClusterLevelTimeout() throws
     public void testMSearchChildReqCancellationWithHybridTimeout() throws Exception {
         List<ScriptedBlockPlugin> plugins = initBlockFactory();
         indexTestData();
-        TimeValue reqCancellationTimeout = new TimeValue(2, TimeUnit.SECONDS);
-        TimeValue clusterCancellationTimeout = new TimeValue(3, TimeUnit.SECONDS);
         client().admin()
             .cluster()
             .prepareUpdateSettings()
@@ -558,7 +573,7 @@ public void testMSearchChildReqCancellationWithHybridTimeout() throws Exception
             .add(
                 client().prepareSearch("test")
                     .setAllowPartialSearchResults(randomBoolean())
-                    .setCancelAfterTimeInterval(reqCancellationTimeout)
+                    .setCancelAfterTimeInterval(requestCancellationTimeout)
                     .setQuery(
                         scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedBlockPlugin.SCRIPT_NAME, Collections.emptyMap()))
                     )
@@ -581,8 +596,7 @@ public void testMSearchChildReqCancellationWithHybridTimeout() throws Exception
             )
             .execute();
         awaitForBlock(plugins);
-        // sleep for cluster cancellation timeout to ensure scheduled cancellation task is actually executed
-        Thread.sleep(Math.max(reqCancellationTimeout.getMillis(), clusterCancellationTimeout.getMillis()));
+        sleepForAtLeast(Math.max(requestCancellationTimeout.getMillis(), clusterCancellationTimeout.getMillis()));
         // unblock the search thread
         disableBlocks(plugins);
         // only first and last child request are expected to fail
@@ -592,6 +606,16 @@ public void testMSearchChildReqCancellationWithHybridTimeout() throws Exception
         ensureMSearchWasCancelled(mSearchResponse, expectedFailedRequests);
     }
 
+    /**
+     * Sleeps for the specified number of milliseconds plus a 100ms buffer to account for system timer/scheduler inaccuracies.
+     *
+     * @param milliseconds The minimum time to sleep
+     * @throws InterruptedException if interrupted during sleep
+     */
+    private static void sleepForAtLeast(long milliseconds) throws InterruptedException {
+        Thread.sleep(milliseconds + 100L);
+    }
+
     public static class ScriptedBlockPlugin extends MockScriptPlugin {
         static final String SCRIPT_NAME = "search_block";
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/SearchTimeoutIT.java b/server/src/internalClusterTest/java/org/opensearch/search/SearchTimeoutIT.java
index 049dcb50024ba..94816346e6c9e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/SearchTimeoutIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/SearchTimeoutIT.java
@@ -32,16 +32,21 @@
 
 package org.opensearch.search;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
@@ -50,11 +55,27 @@
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.index.query.QueryBuilders.scriptQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.SearchTimeoutIT.ScriptedTimeoutPlugin.SCRIPT_NAME;
-import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class SearchTimeoutIT extends OpenSearchIntegTestCase {
+public class SearchTimeoutIT extends ParameterizedOpenSearchIntegTestCase {
+    public SearchTimeoutIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -67,17 +88,36 @@ protected Settings nodeSettings(int nodeOrdinal) {
     }
 
     public void testSimpleTimeout() throws Exception {
-        for (int i = 0; i < 32; i++) {
+        final int numDocs = 1000;
+        for (int i = 0; i < numDocs; i++) {
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").get();
+        }
+        refresh("test");
+
+        SearchResponse searchResponse = client().prepareSearch("test")
+            .setTimeout(new TimeValue(5, TimeUnit.MILLISECONDS))
+            .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", SCRIPT_NAME, Collections.emptyMap())))
+            .setAllowPartialSearchResults(true)
+            .get();
+        assertTrue(searchResponse.isTimedOut());
+        assertEquals(0, searchResponse.getFailedShards());
+    }
+
+    public void testSimpleDoesNotTimeout() throws Exception {
+        final int numDocs = 10;
+        for (int i = 0; i < numDocs; i++) {
             client().prepareIndex("test").setId(Integer.toString(i)).setSource("field", "value").get();
         }
         refresh("test");
 
         SearchResponse searchResponse = client().prepareSearch("test")
-            .setTimeout(new TimeValue(10, TimeUnit.MILLISECONDS))
+            .setTimeout(new TimeValue(10000, TimeUnit.SECONDS))
             .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", SCRIPT_NAME, Collections.emptyMap())))
             .setAllowPartialSearchResults(true)
             .get();
-        assertThat(searchResponse.isTimedOut(), equalTo(true));
+        assertFalse(searchResponse.isTimedOut());
+        assertEquals(0, searchResponse.getFailedShards());
+        assertEquals(numDocs, searchResponse.getHits().getTotalHits().value);
     }
 
     public void testPartialResultsIntolerantTimeout() throws Exception {
@@ -91,7 +131,7 @@ public void testPartialResultsIntolerantTimeout() throws Exception {
                 .setAllowPartialSearchResults(false) // this line causes timeouts to report failures
                 .get()
         );
-        assertTrue(ex.toString().contains("Time exceeded"));
+        assertTrue(ex.toString().contains("QueryPhaseExecutionException[Time exceeded]"));
     }
 
     public static class ScriptedTimeoutPlugin extends MockScriptPlugin {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java
new file mode 100644
index 0000000000000..0975585e2984d
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java
@@ -0,0 +1,1463 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search;
+
+import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.opensearch.action.admin.cluster.node.stats.NodeStats;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
+import org.opensearch.action.get.MultiGetRequest;
+import org.opensearch.action.get.MultiGetResponse;
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.PreferenceBasedSearchNotAllowedException;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.routing.WeightedRoutingStats;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.index.search.stats.SearchStats;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.Aggregations;
+import org.opensearch.search.aggregations.bucket.terms.Terms;
+import org.opensearch.snapshots.mockstore.MockRepository;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.disruption.NetworkDisruption;
+import org.opensearch.test.transport.MockTransportService;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.opensearch.action.search.TransportSearchAction.SEARCH_REQUEST_STATS_ENABLED_KEY;
+import static org.opensearch.search.aggregations.AggregationBuilders.terms;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, minNumDataNodes = 3)
+public class SearchWeightedRoutingIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(MockTransportService.TestPlugin.class, MockRepository.Plugin.class);
+    }
+
+    public void testSearchWithWRRShardRouting() throws IOException {
+        Settings commonSettings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone" + ".values", "a,b,c")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .put("cluster.routing.weighted.fail_open", false)
+            .put(SEARCH_REQUEST_STATS_ENABLED_KEY, true)
+            .build();
+
+        logger.info("--> starting 6 nodes on different zones");
+        List<String> nodes = internalCluster().startNodes(
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build(),
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+
+        String A_0 = nodes.get(0);
+        String B_0 = nodes.get(1);
+        String B_1 = nodes.get(2);
+        String A_1 = nodes.get(3);
+        String C_0 = nodes.get(4);
+        String C_1 = nodes.get(5);
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("6").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        assertAcked(
+            prepareCreate("test").setSettings(Settings.builder().put("index.number_of_shards", 10).put("index.number_of_replicas", 2))
+        );
+        ensureGreen();
+        logger.info("--> creating indices for test");
+        for (int i = 0; i < 100; i++) {
+            client().prepareIndex("test_" + i).setId("" + i).setSource("field_" + i, "value_" + i).get();
+        }
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+
+        Set<String> hitNodes = new HashSet<>();
+        // making search requests
+        for (int i = 0; i < 50; i++) {
+            SearchResponse searchResponse = internalCluster().client(randomFrom(A_0, A_1, B_0, B_1))
+                .prepareSearch()
+                .setQuery(QueryBuilders.matchAllQuery())
+                .get();
+            assertEquals(searchResponse.getFailedShards(), 0);
+            for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+            }
+        }
+        // search should not go to nodes in zone c with weight zero in case
+        // shard copies are available in other zones
+        assertThat(hitNodes.size(), lessThanOrEqualTo(4));
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        List<String> nodeIdsFromZoneWithWeightZero = new ArrayList<>();
+        for (DiscoveryNode node : dataNodes) {
+            if (node.getAttributes().get("zone").equals("c")) {
+                nodeIdsFromZoneWithWeightZero.add(node.getId());
+            }
+        }
+        for (String nodeId : nodeIdsFromZoneWithWeightZero) {
+            assertFalse(hitNodes.contains(nodeId));
+        }
+
+        NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats().execute().actionGet();
+        for (NodeStats stat : nodeStats.getNodes()) {
+            SearchStats.Stats searchStats = stat.getIndices().getSearch().getTotal();
+            if (stat.getNode().getAttributes().get("zone").equals("c")) {
+                assertEquals(0, searchStats.getQueryCount());
+                assertEquals(0, searchStats.getFetchCount());
+
+            } else {
+                Assert.assertTrue(searchStats.getQueryCount() > 0L);
+                Assert.assertTrue(searchStats.getFetchCount() > 0L);
+            }
+        }
+
+        logger.info("--> deleted shard routing weights for weighted round robin");
+
+        ClusterDeleteWeightedRoutingResponse deleteResponse = client().admin().cluster().prepareDeleteWeightedRouting().setVersion(0).get();
+        assertEquals(deleteResponse.isAcknowledged(), true);
+
+        hitNodes = new HashSet<>();
+        // making search requests
+        for (int i = 0; i < 100; i++) {
+            SearchResponse searchResponse = internalCluster().client(randomFrom(A_0, A_1, B_0, B_1))
+                .prepareSearch()
+                .setQuery(QueryBuilders.matchAllQuery())
+                .get();
+            assertEquals(searchResponse.getFailedShards(), 0);
+            for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+            }
+        }
+
+        // Check shard routing requests hit data nodes in zone c
+        for (String nodeId : nodeIdsFromZoneWithWeightZero) {
+            assertFalse(!hitNodes.contains(nodeId));
+        }
+        nodeStats = client().admin().cluster().prepareNodesStats().execute().actionGet();
+        int num = 0;
+        int coordNumber = 0;
+
+        for (NodeStats stat : nodeStats.getNodes()) {
+            SearchStats.Stats searchStats = stat.getIndices().getSearch().getTotal();
+            if (searchStats.getRequestStatsLongHolder()
+                .getRequestStatsHolder()
+                .get(SearchPhaseName.QUERY.getName())
+                .getTimeInMillis() > 0) {
+                assertThat(
+                    searchStats.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.QUERY.getName()).getTotal(),
+                    greaterThan(0L)
+                );
+                assertThat(
+                    searchStats.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.FETCH.getName()).getTimeInMillis(),
+                    greaterThan(0L)
+                );
+                assertThat(
+                    searchStats.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.FETCH.getName()).getTotal(),
+                    greaterThan(0L)
+                );
+                assertThat(
+                    searchStats.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.EXPAND.getName()).getTotal(),
+                    greaterThan(0L)
+                );
+                coordNumber += 1;
+            }
+            Assert.assertTrue(searchStats.getQueryCount() > 0L);
+            Assert.assertTrue(searchStats.getFetchCount() > 0L);
+            num++;
+        }
+        assertThat(coordNumber, greaterThan(0));
+        assertThat(num, greaterThan(0));
+    }
+
+    private Map<String, List<String>> setupCluster(int nodeCountPerAZ, Settings commonSettings) {
+
+        logger.info("--> starting a dedicated cluster manager node");
+        internalCluster().startClusterManagerOnlyNode(Settings.builder().put(commonSettings).build());
+
+        logger.info("--> starting 1 nodes on zones 'a' & 'b' & 'c'");
+        Map<String, List<String>> nodeMap = new HashMap<>();
+        List<String> nodes_in_zone_a = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "a").build()
+        );
+        nodeMap.put("a", nodes_in_zone_a);
+        List<String> nodes_in_zone_b = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "b").build()
+        );
+        nodeMap.put("b", nodes_in_zone_b);
+
+        List<String> nodes_in_zone_c = internalCluster().startDataOnlyNodes(
+            nodeCountPerAZ,
+            Settings.builder().put(commonSettings).put("node.attr.zone", "c").build()
+        );
+        nodeMap.put("c", nodes_in_zone_c);
+
+        logger.info("--> waiting for nodes to form a cluster");
+        ClusterHealthResponse health = client().admin().cluster().prepareHealth().setWaitForNodes("4").execute().actionGet();
+        assertThat(health.isTimedOut(), equalTo(false));
+
+        ensureGreen();
+        return nodeMap;
+
+    }
+
+    private void setUpIndexing(int numShards, int numReplicas) {
+        assertAcked(
+            prepareCreate("test").setSettings(
+                Settings.builder().put("index.number_of_shards", numShards).put("index.number_of_replicas", numReplicas)
+            )
+        );
+        ensureGreen();
+
+        logger.info("--> creating indices for test");
+        for (int i = 0; i < 100; i++) {
+            client().prepareIndex("test").setId("" + i).setSource("field_" + i, "value_" + i).get();
+        }
+        refresh("test");
+    }
+
+    private void setShardRoutingWeights(Map<String, Double> weights) {
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        ClusterPutWeightedRoutingResponse response = client().admin()
+            .cluster()
+            .prepareWeightedRouting()
+            .setWeightedRouting(weightedRouting)
+            .setVersion(-1)
+            .get();
+        assertEquals(response.isAcknowledged(), true);
+    }
+
+    /**
+     * Shard routing request fail without fail-open if there are no healthy nodes in active az to serve request
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Data nodes in zone a and b are stopped,
+     * assertions are put to check that search requests fail.
+     * @throws Exception throws Exception
+     */
+    public void testShardRoutingByStoppingDataNodes_FailOpenDisabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", false)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 1;
+        int numReplicas = 2;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> data nodes in zone a and b are stopped");
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeMap.get("a").get(0)));
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeMap.get("b").get(0)));
+        ensureStableCluster(2);
+
+        Set<String> hitNodes = new HashSet<>();
+
+        // Make Search Requests
+        Future<SearchResponse>[] responses = new Future[50];
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().smartClient().prepareSearch("test").setQuery(QueryBuilders.matchAllQuery()).execute();
+        }
+        int failedCount = 0;
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(0, searchResponse.getFailedShards());
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                failedCount++;
+            }
+        }
+
+        Assert.assertTrue(failedCount > 0);
+        logger.info("--> failed request count is [()]", failedCount);
+        assertNoSearchInAZ("c");
+    }
+
+    /**
+     * Shard routing request with fail open enabled is served by data nodes in az with weight set as 0,
+     * in case shard copies are not available in other azs (with fail open enabled)
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Data nodes in zone a and b are stopped,
+     * assertions are put to make sure shard search requests do not fail.
+     * @throws IOException throws exception
+     */
+    public void testShardRoutingByStoppingDataNodes_FailOpenEnabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 1;
+        int numReplicas = 2;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> data nodes in zone a and b are stopped");
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeMap.get("a").get(0)));
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(nodeMap.get("b").get(0)));
+        ensureStableCluster(2);
+
+        Set<String> hitNodes = new HashSet<>();
+
+        // Make Search Requests
+        Future<SearchResponse>[] responses = new Future[50];
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().smartClient().prepareSearch("test").setQuery(QueryBuilders.matchAllQuery()).execute();
+        }
+        int failedCount = 0;
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(0, searchResponse.getFailedShards());
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                failedCount++;
+            }
+        }
+
+        Assert.assertTrue(failedCount == 0);
+        assertSearchInAZ("c");
+    }
+
+    /**
+     * Shard routing request with fail open disabled is not served by data nodes in az with weight set as 0,
+     * in case shard copies are not available in other azs.
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Indices are created with one replica copy and network disruption is introduced,
+     * which makes data node in zone-a unresponsive.
+     * Since there are two copies of a shard, there can be few shards for which copy doesn't exist in zone b.
+     * Assertions are put to make sure such shard search requests are not served by data node in zone c.
+     * @throws IOException throws exception
+     */
+    public void testShardRoutingWithNetworkDisruption_FailOpenDisabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", false)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0), nodeMap.get("c").get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        Future<SearchResponse>[] responses = new Future[50];
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("test")
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        int failedShardCount = 0;
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                failedShardCount += searchResponse.getFailedShards();
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+        Assert.assertTrue(failedShardCount > 0);
+        // assert that no search request goes to az with weight zero
+        assertNoSearchInAZ("c");
+    }
+
+    /**
+     * Shard routing request is served by data nodes in az with weight set as 0,
+     * in case shard copies are not available in other azs.(with fail open enabled)
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Indices are created with one replica copy and network disruption is introduced,
+     * which makes data node in zone-a unresponsive.
+     * Since there are two copies of a shard, there can be few shards for which copy doesn't exist in zone b.
+     * Assertions are put to make sure such shard search requests are served by data node in zone c.
+     * @throws IOException throws exception
+     */
+    public void testShardRoutingWithNetworkDisruption_FailOpenEnabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0)).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        Future<SearchResponse>[] responses = new Future[50];
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("test")
+                .setSize(100)
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(searchResponse.getFailedShards(), 0);
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        assertSearchInAZ("b");
+        assertSearchInAZ("c");
+        assertNoSearchInAZ("a");
+    }
+
+    public void testStrictWeightedRoutingWithCustomString_FailOpenEnabled() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0)).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        Future<SearchResponse>[] responses = new Future[50];
+        String customPreference = randomAlphaOfLength(10);
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("test")
+                .setPreference(customPreference)
+                .setSize(100)
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        logger.info("--> shards should fail due to network disruption");
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(searchResponse.getFailedShards(), 0);
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        try {
+            assertSearchInAZ("b");
+        } catch (AssertionError ae) {
+            assertSearchInAZ("c");
+        }
+        assertNoSearchInAZ("a");
+    }
+
+    public void testStrictWeightedRoutingWithCustomString_FailOpenDisabled() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", false)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0)).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        Future<SearchResponse>[] responses = new Future[50];
+        String customPreference = randomAlphaOfLength(10);
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("test")
+                .setPreference(customPreference)
+                .setSize(100)
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        logger.info("--> shards should fail due to network disruption");
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertNotEquals(searchResponse.getFailedShards(), 0);
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        Set<String> expectedHotNodes = new HashSet<>();
+        for (DiscoveryNode node : dataNodes) {
+            if (node.getAttributes().getOrDefault("zone", "").equals("b")) {
+                expectedHotNodes.add(node.getId());
+            }
+        }
+
+        assertEquals(expectedHotNodes, hitNodes);
+
+        assertSearchInAZ("b");
+        assertNoSearchInAZ("c");
+        assertNoSearchInAZ("a");
+    }
+
+    /**
+     * Should failopen shards even if failopen enabled with custom search preference.
+     */
+    public void testStrictWeightedRoutingWithShardPrefNetworkDisruption_FailOpenEnabled() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("c").get(0)).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Future<SearchResponse>[] responses = new Future[50];
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        ShardId shardId = internalCluster().clusterService()
+            .state()
+            .getRoutingTable()
+            .index("test")
+            .randomAllActiveShardsIt()
+            .getShardRoutings()
+            .stream()
+            .filter(shard -> {
+                return dataNodes.get(shard.currentNodeId()).getAttributes().getOrDefault("zone", "").equals("c");
+            })
+            .findFirst()
+            .get()
+            .shardId();
+
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("c").get(0))
+                .prepareSearch("test")
+                .setPreference(String.format(Locale.ROOT, "_shards:%s", shardId.getId()))
+                .setSize(100)
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(searchResponse.getFailedShards(), 0);
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        assertNoSearchInAZ("a");
+        try {
+            assertSearchInAZ("c");
+        } catch (AssertionError ae) {
+            assertSearchInAZ("b");
+        }
+    }
+
+    public void testStrictWeightedRoutingWithShardPref() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        ShardId shardId = internalCluster().clusterService()
+            .state()
+            .getRoutingTable()
+            .index("test")
+            .randomAllActiveShardsIt()
+            .getShardRoutings()
+            .stream()
+            .filter(shard -> {
+                return dataNodes.get(shard.currentNodeId()).getAttributes().getOrDefault("zone", "").equals("c");
+            })
+            .findFirst()
+            .get()
+            .shardId();
+
+        Future<SearchResponse>[] responses = new Future[50];
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("test")
+                .setPreference(String.format(Locale.ROOT, "_shards:%s", shardId.getId()))
+                .setSize(100)
+                .setQuery(QueryBuilders.matchAllQuery())
+                .execute();
+        }
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                assertEquals(searchResponse.getFailedShards(), 0);
+                assertNotEquals(searchResponse.getHits().getTotalHits().value, 0);
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+        assertNoSearchInAZ("c");
+    }
+
+    private void assertNoSearchInAZ(String az) {
+        final Map<String, DiscoveryNode> dataNodes = internalCluster().clusterService().state().nodes().getDataNodes();
+        String dataNodeId = null;
+
+        for (Iterator<DiscoveryNode> it = dataNodes.values().iterator(); it.hasNext();) {
+            DiscoveryNode node = it.next();
+            if (node.getAttributes().get("zone").equals(az)) {
+                dataNodeId = node.getId();
+                break;
+            }
+        }
+
+        NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats().execute().actionGet();
+        for (NodeStats stat : nodeStats.getNodes()) {
+            SearchStats.Stats searchStats = stat.getIndices().getSearch().getTotal();
+            if (stat.getNode().isDataNode()) {
+                if (stat.getNode().getId().equals(dataNodeId)) {
+                    assertEquals(0, searchStats.getQueryCount());
+                    assertEquals(0, searchStats.getFetchCount());
+                }
+            }
+        }
+    }
+
+    private void assertSearchInAZ(String az) {
+        final Map<String, DiscoveryNode> dataNodes = internalCluster().clusterService().state().nodes().getDataNodes();
+        String dataNodeId = null;
+
+        for (Iterator<DiscoveryNode> it = dataNodes.values().iterator(); it.hasNext();) {
+            DiscoveryNode node = it.next();
+            if (node.getAttributes().get("zone").equals(az)) {
+                dataNodeId = node.getId();
+                break;
+            }
+        }
+
+        NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats().execute().actionGet();
+        for (NodeStats stat : nodeStats.getNodes()) {
+            SearchStats.Stats searchStats = stat.getIndices().getSearch().getTotal();
+            if (stat.getNode().isDataNode()) {
+                if (stat.getNode().getId().equals(dataNodeId)) {
+                    Assert.assertTrue(searchStats.getFetchCount() > 0L);
+                    Assert.assertTrue(searchStats.getQueryCount() > 0L);
+                }
+            }
+        }
+    }
+
+    /**
+     * Shard routing request is served by data nodes in az with weight set as 0,
+     * in case shard copies are not available in other azs.
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Indices are created with one replica copy and network disruption is introduced,
+     * which makes node in zone-a unresponsive.
+     * Since there are two copies of a shard, there can be few shards for which copy doesn't exist in zone b.
+     * Assertions are put to make sure such shard search requests are served by data node in zone c.
+     * @throws IOException throws exception
+     */
+    public void testSearchAggregationWithNetworkDisruption_FailOpenEnabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        assertAcked(
+            prepareCreate("index").setMapping("f", "type=keyword")
+                .setSettings(Settings.builder().put("index" + ".number_of_shards", 10).put("index" + ".number_of_replicas", 1))
+        );
+
+        int numDocs = 10;
+        List<IndexRequestBuilder> docs = new ArrayList<>();
+        for (int i = 0; i < numDocs; ++i) {
+            docs.add(client().prepareIndex("index").setSource("f", Integer.toString(i / 3)));
+        }
+        indexRandom(true, docs);
+        ensureGreen();
+        refresh("index");
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0), nodeMap.get("c").get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        Future<SearchResponse>[] responses = new Future[51];
+        int size = 17;
+        logger.info("--> making search requests");
+        for (int i = 0; i < 50; i++) {
+            responses[i] = internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch("index")
+                .setSize(20)
+                .addAggregation(terms("f").field("f"))
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                SearchResponse searchResponse = responses[i].get();
+                Aggregations aggregations = searchResponse.getAggregations();
+                assertNotNull(aggregations);
+                Terms terms = aggregations.get("f");
+                assertEquals(0, searchResponse.getFailedShards());
+                assertEquals(Math.min(numDocs, 3L), terms.getBucketByKey("0").getDocCount());
+                for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                    hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+        assertSearchInAZ("b");
+        assertSearchInAZ("c");
+        assertNoSearchInAZ("a");
+
+        assertBusy(
+            () -> assertThat(client().admin().indices().prepareStats().get().getTotal().getSearch().getOpenContexts(), equalTo(0L)),
+            60,
+            TimeUnit.SECONDS
+        );
+    }
+
+    /**
+     * MultiGet with fail open enabled. No request failure on network disruption
+     * @throws IOException throws exception
+     */
+    public void testMultiGetWithNetworkDisruption_FailOpenEnabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0), nodeMap.get("c").get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Future<MultiGetResponse>[] responses = new Future[50];
+        logger.info("--> making search requests");
+        int index1, index2;
+        for (int i = 0; i < 50; i++) {
+            index1 = randomIntBetween(0, 9);
+            index2 = randomIntBetween(0, 9);
+            responses[i] = client().prepareMultiGet()
+                .add(new MultiGetRequest.Item("test", "" + index1))
+                .add(new MultiGetRequest.Item("test", "" + index2))
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        for (int i = 0; i < 50; i++) {
+            try {
+                MultiGetResponse multiGetResponse = responses[i].get();
+                assertThat(multiGetResponse.getResponses().length, equalTo(2));
+                assertThat(multiGetResponse.getResponses()[0].isFailed(), equalTo(false));
+                assertThat(multiGetResponse.getResponses()[1].isFailed(), equalTo(false));
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        assertBusy(
+            () -> assertThat(client().admin().indices().prepareStats().get().getTotal().getSearch().getOpenContexts(), equalTo(0L)),
+            60,
+            TimeUnit.SECONDS
+        );
+    }
+
+    /**
+     * MultiGet with fail open disabled. Assert that some requests do fail.
+     * @throws IOException throws exception
+     */
+    public void testMultiGetWithNetworkDisruption_FailOpenDisabled() throws Exception {
+
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", false)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0), nodeMap.get("c").get(0))
+            .collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Future<MultiGetResponse>[] responses = new Future[50];
+        logger.info("--> making search requests");
+        int index1, index2;
+        for (int i = 0; i < 50; i++) {
+            index1 = randomIntBetween(0, 9);
+            index2 = randomIntBetween(0, 9);
+            responses[i] = client().prepareMultiGet()
+                .add(new MultiGetRequest.Item("test", "" + index1))
+                .add(new MultiGetRequest.Item("test", "" + index2))
+                .execute();
+        }
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+        int failedCount = 0;
+        for (int i = 0; i < 50; i++) {
+            try {
+                MultiGetResponse multiGetResponse = responses[i].get();
+                assertThat(multiGetResponse.getResponses().length, equalTo(2));
+                if (multiGetResponse.getResponses()[0].isFailed() || multiGetResponse.getResponses()[1].isFailed()) {
+                    failedCount++;
+                }
+            } catch (Exception t) {
+                fail("search should not fail");
+            }
+        }
+
+        Assert.assertTrue(failedCount > 0);
+
+        assertBusy(
+            () -> assertThat(client().admin().indices().prepareStats().get().getTotal().getSearch().getOpenContexts(), equalTo(0L)),
+            60,
+            TimeUnit.SECONDS
+        );
+    }
+
+    /**
+     * Assert that preference based search is not allowed with strict weighted shard routing
+     */
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8030")
+    public void testStrictWeightedRoutingWithCustomString() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+        String nodeInZoneA = nodeMap.get("a").get(0);
+        String customPreference = randomAlphaOfLength(10);
+
+        SearchResponse searchResponse = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch()
+            .setSize(20)
+            .setPreference(customPreference)
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+        assertNoSearchInAZ("c");
+        assertSearchInAZ("a");
+        assertSearchInAZ("b");
+
+        // disable strict weighed routing
+        client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().put("cluster.routing.weighted.strict", false))
+            .get();
+
+        // make search requests with custom string
+        internalCluster().client(nodeMap.get("a").get(0))
+            .prepareSearch()
+            .setSize(20)
+            .setPreference(customPreference)
+            .setQuery(QueryBuilders.matchAllQuery())
+            .get();
+        // assert search on data nodes on az c (weighed away az)
+        try {
+            assertSearchInAZ("c");
+        } catch (AssertionError ae) {
+            assertSearchInAZ("a");
+        }
+    }
+
+    /**
+     *  Assert that preference based search works with non-strict weighted shard routing
+     */
+    public void testPreferenceSearchWithWeightedRouting() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", false)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 2;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        String customPreference = randomAlphaOfLength(10);
+        String nodeInZoneA = nodeMap.get("a").get(0);
+        String nodeInZoneB = nodeMap.get("b").get(0);
+        String nodeInZoneC = nodeMap.get("c").get(0);
+
+        Map<String, String> nodeIDMap = new HashMap<>();
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        for (DiscoveryNode node : dataNodes) {
+            nodeIDMap.put(node.getName(), node.getId());
+        }
+        SearchResponse searchResponse = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch()
+            .setPreference(randomFrom("_local", "_prefer_nodes:" + "zone:a", customPreference))
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+
+        searchResponse = internalCluster().client(nodeMap.get("a").get(0))
+            .prepareSearch()
+            .setPreference(
+                "_only_nodes:" + nodeIDMap.get(nodeInZoneA) + "," + nodeIDMap.get(nodeInZoneB) + "," + nodeIDMap.get(nodeInZoneC)
+            )
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+    }
+
+    public void testPreferenceSearchWithIgnoreWeightedRouting() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", false)
+            .put("cluster.routing.ignore_weighted_routing", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 2;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+
+        String customPreference = randomAlphaOfLength(10);
+        String nodeInZoneA = nodeMap.get("a").get(0);
+        String nodeInZoneB = nodeMap.get("b").get(0);
+        String nodeInZoneC = nodeMap.get("c").get(0);
+
+        Map<String, String> nodeIDMap = new HashMap<>();
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+        for (DiscoveryNode node : dataNodes) {
+            nodeIDMap.put(node.getName(), node.getId());
+        }
+
+        SearchResponse searchResponse = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch()
+            .setPreference(randomFrom("_local", "_prefer_nodes:" + "zone:a", customPreference))
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+
+        searchResponse = internalCluster().client(nodeMap.get("a").get(0))
+            .prepareSearch()
+            .setPreference(
+                "_only_nodes:" + nodeIDMap.get(nodeInZoneA) + "," + nodeIDMap.get(nodeInZoneB) + "," + nodeIDMap.get(nodeInZoneC)
+            )
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+    }
+
+    /**
+     * Assert that preference based search with preference type is not allowed with strict weighted shard routing
+     */
+    public void testStrictWeightedRouting() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+        String nodeInZoneA = nodeMap.get("a").get(0);
+
+        assertThrows(
+            PreferenceBasedSearchNotAllowedException.class,
+            () -> internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch()
+                .setSize(0)
+                .setPreference("_only_nodes:" + nodeInZoneA)
+                .get()
+        );
+
+        assertThrows(
+            PreferenceBasedSearchNotAllowedException.class,
+            () -> internalCluster().client(nodeMap.get("b").get(0))
+                .prepareSearch()
+                .setSize(0)
+                .setPreference("_prefer_nodes:" + nodeInZoneA)
+                .get()
+        );
+    }
+
+    public void testStrictWeightedRoutingAllowedForSomeSearchPrefs() {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .put("cluster.routing.weighted.strict", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+        String nodeInZoneA = nodeMap.get("a").get(0);
+        String customPreference = randomAlphaOfLength(10);
+
+        SearchResponse searchResponse = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch()
+            .setSize(0)
+            .setPreference("_only_local:" + nodeInZoneA)
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+
+        searchResponse = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch()
+            .setSize(0)
+            .setPreference("_local:" + nodeInZoneA)
+            .get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+
+        searchResponse = internalCluster().client(nodeMap.get("b").get(0)).prepareSearch().setSize(0).setPreference("_shards:1").get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+
+        searchResponse = internalCluster().client(nodeMap.get("b").get(0)).prepareSearch().setSize(0).setPreference(customPreference).get();
+        assertEquals(RestStatus.OK.getStatus(), searchResponse.status().getStatus());
+    }
+
+    /**
+     * Shard routing request is served by data nodes in az with weight set as 0,
+     * in case shard copies are not available in other azs.(with fail open enabled)
+     * This is tested by setting up a 3 node cluster with one data node per az.
+     * Weighted shard routing weight is set as 0 for az-c.
+     * Indices are created with one replica copy and network disruption is introduced,
+     * which makes data node in zone-a unresponsive.
+     * Since there are two copies of a shard, there can be few shards for which copy doesn't exist in zone b.
+     * Assertions are put to make sure such shard search requests are served by data node in zone c.
+     * Asserts on fail open stats which captures number of times fail open is executed
+     * @throws IOException throws exception
+     */
+    public void testWeightedRoutingFailOpenStats() throws Exception {
+        Settings commonSettings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .put("cluster.routing.weighted.fail_open", true)
+            .build();
+
+        int nodeCountPerAZ = 1;
+        Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
+
+        int numShards = 10;
+        int numReplicas = 1;
+        setUpIndexing(numShards, numReplicas);
+
+        logger.info("--> setting shard routing weights for weighted round robin");
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        setShardRoutingWeights(weights);
+        WeightedRoutingStats.getInstance().resetFailOpenCount();
+
+        logger.info("--> creating network partition disruption");
+        final String clusterManagerNode1 = internalCluster().getClusterManagerName();
+        Set<String> nodesInOneSide = Stream.of(clusterManagerNode1, nodeMap.get("b").get(0)).collect(Collectors.toCollection(HashSet::new));
+        Set<String> nodesInOtherSide = Stream.of(nodeMap.get("a").get(0)).collect(Collectors.toCollection(HashSet::new));
+
+        NetworkDisruption networkDisruption = new NetworkDisruption(
+            new NetworkDisruption.TwoPartitions(nodesInOneSide, nodesInOtherSide),
+            NetworkDisruption.UNRESPONSIVE
+        );
+        internalCluster().setDisruptionScheme(networkDisruption);
+
+        DiscoveryNodes dataNodes = internalCluster().clusterService().state().nodes();
+
+        Map<String, String> nodeIDMap = new HashMap<>();
+        for (DiscoveryNode node : dataNodes) {
+            nodeIDMap.put(node.getName(), node.getId());
+        }
+
+        List<ShardRouting> shardInNodeA = internalCluster().clusterService()
+            .state()
+            .getRoutingNodes()
+            .node(nodeIDMap.get(nodeMap.get("a").get(0)))
+            .shardsWithState(ShardRoutingState.STARTED);
+
+        List<ShardRouting> shardInNodeC = internalCluster().clusterService()
+            .state()
+            .getRoutingNodes()
+            .node(nodeIDMap.get(nodeMap.get("c").get(0)))
+            .shardsWithState(ShardRoutingState.STARTED);
+
+        // fail open will be called for shards in zone-a data node with replica in zone-c data node
+        Set<ShardId> result = new HashSet<>();
+        int failOpenShardCount = 0;
+        for (ShardRouting shardRouting : shardInNodeA) {
+            result.add(shardRouting.shardId());
+        }
+        for (ShardRouting shardRouting : shardInNodeC) {
+            if (result.contains(shardRouting.shardId())) {
+                failOpenShardCount++;
+            }
+        }
+
+        logger.info("--> network disruption is started");
+        networkDisruption.startDisrupting();
+
+        Set<String> hitNodes = new HashSet<>();
+        logger.info("--> making search requests");
+
+        Future<SearchResponse> response = internalCluster().client(nodeMap.get("b").get(0))
+            .prepareSearch("test")
+            .setSize(100)
+            .setQuery(QueryBuilders.matchAllQuery())
+            .execute();
+
+        logger.info("--> network disruption is stopped");
+        networkDisruption.stopDisrupting();
+
+        try {
+            SearchResponse searchResponse = response.get();
+            assertEquals(searchResponse.getFailedShards(), 0);
+            for (int j = 0; j < searchResponse.getHits().getHits().length; j++) {
+                hitNodes.add(searchResponse.getHits().getAt(j).getShard().getNodeId());
+            }
+        } catch (Exception t) {
+            fail("search should not fail");
+        }
+        assertSearchInAZ("b");
+        assertSearchInAZ("c");
+        assertNoSearchInAZ("a");
+
+        NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats().addMetric("weighted_routing").execute().actionGet();
+        Map<String, NodeStats> stats = nodeStats.getNodesMap();
+        NodeStats nodeStatsC = stats.get(nodeIDMap.get(nodeMap.get("c").get(0)));
+        assertEquals(failOpenShardCount, nodeStatsC.getWeightedRoutingStats().getFailOpenCount());
+        WeightedRoutingStats.getInstance().resetFailOpenCount();
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/SearchWithRejectionsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/SearchWithRejectionsIT.java
index 30e6aa4cd31fc..24c72a66da6d0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/SearchWithRejectionsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/SearchWithRejectionsIT.java
@@ -32,21 +32,45 @@
 
 package org.opensearch.search;
 
-import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class SearchWithRejectionsIT extends OpenSearchIntegTestCase {
+public class SearchWithRejectionsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchWithRejectionsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public Settings nodeSettings(int nodeOrdinal) {
         return Settings.builder()
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/StressSearchServiceReaperIT.java b/server/src/internalClusterTest/java/org/opensearch/search/StressSearchServiceReaperIT.java
index 42e515cca9b6b..a61102b9db144 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/StressSearchServiceReaperIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/StressSearchServiceReaperIT.java
@@ -31,23 +31,45 @@
 
 package org.opensearch.search;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.tests.util.English;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.concurrent.ExecutionException;
 
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.OpenSearchIntegTestCase.Scope.SUITE;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 
 @ClusterScope(scope = SUITE)
-public class StressSearchServiceReaperIT extends OpenSearchIntegTestCase {
+public class StressSearchServiceReaperIT extends ParameterizedOpenSearchIntegTestCase {
+    public StressSearchServiceReaperIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/AggregationsIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/AggregationsIntegrationIT.java
index 6778765599fe9..257786c1e9ce5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/AggregationsIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/AggregationsIntegrationIT.java
@@ -32,24 +32,62 @@
 
 package org.opensearch.search.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
+import org.opensearch.search.aggregations.bucket.terms.RareTermsAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.SignificantTermsAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.SignificantTermsAggregatorFactory;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregatorFactory;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class AggregationsIntegrationIT extends OpenSearchIntegTestCase {
+public class AggregationsIntegrationIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int numDocs;
 
+    private static final String LARGE_STRING = "a".repeat(2000);
+    private static final String LARGE_STRING_EXCEPTION_MESSAGE = "The length of regex ["
+        + LARGE_STRING.length()
+        + "] used in the request has exceeded the allowed maximum";
+
+    public AggregationsIntegrationIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(prepareCreate("index").setMapping("f", "type=keyword").get());
@@ -85,4 +123,51 @@ public void testScroll() {
         assertEquals(numDocs, total);
     }
 
+    public void testLargeRegExTermsAggregation() {
+        for (TermsAggregatorFactory.ExecutionMode executionMode : TermsAggregatorFactory.ExecutionMode.values()) {
+            TermsAggregationBuilder termsAggregation = terms("my_terms").field("f")
+                .includeExclude(getLargeStringInclude())
+                .executionHint(executionMode.toString());
+            runLargeStringAggregationTest(termsAggregation);
+        }
+    }
+
+    public void testLargeRegExSignificantTermsAggregation() {
+        for (SignificantTermsAggregatorFactory.ExecutionMode executionMode : SignificantTermsAggregatorFactory.ExecutionMode.values()) {
+            SignificantTermsAggregationBuilder significantTerms = new SignificantTermsAggregationBuilder("my_terms").field("f")
+                .includeExclude(getLargeStringInclude())
+                .executionHint(executionMode.toString());
+            runLargeStringAggregationTest(significantTerms);
+        }
+    }
+
+    public void testLargeRegExRareTermsAggregation() {
+        // currently this only supports "map" as an execution hint
+        RareTermsAggregationBuilder rareTerms = new RareTermsAggregationBuilder("my_terms").field("f")
+            .includeExclude(getLargeStringInclude())
+            .maxDocCount(2);
+        runLargeStringAggregationTest(rareTerms);
+    }
+
+    private IncludeExclude getLargeStringInclude() {
+        return new IncludeExclude(LARGE_STRING, null);
+    }
+
+    private void runLargeStringAggregationTest(AggregationBuilder aggregation) {
+        boolean exceptionThrown = false;
+        IncludeExclude include = new IncludeExclude(LARGE_STRING, null);
+        try {
+            client().prepareSearch("index").addAggregation(aggregation).get();
+        } catch (SearchPhaseExecutionException ex) {
+            exceptionThrown = true;
+            Throwable nestedException = ex.getCause();
+            assertNotNull(nestedException);
+            assertTrue(nestedException instanceof OpenSearchException);
+            assertNotNull(nestedException.getCause());
+            assertTrue(nestedException.getCause() instanceof IllegalArgumentException);
+            String actualExceptionMessage = nestedException.getCause().getMessage();
+            assertTrue(actualExceptionMessage.startsWith(LARGE_STRING_EXCEPTION_MESSAGE));
+        }
+        assertTrue("Exception should have been thrown", exceptionThrown);
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/CombiIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/CombiIT.java
index c5794c76e21de..3d3cf1943dfe3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/CombiIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/CombiIT.java
@@ -32,20 +32,27 @@
 
 package org.opensearch.search.aggregations;
 
-import com.carrotsearch.hppc.IntIntHashMap;
-import com.carrotsearch.hppc.IntIntMap;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.missing.Missing;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.missing;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -54,7 +61,24 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.core.IsNull.notNullValue;
 
-public class CombiIT extends OpenSearchIntegTestCase {
+public class CombiIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public CombiIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     /**
      * Making sure that if there are multiple aggregations, working on the same field, yet require different
@@ -67,7 +91,7 @@ public void testMultipleAggsOnSameField_WithDifferentRequiredValueSourceType() t
 
         createIndex("idx");
         IndexRequestBuilder[] builders = new IndexRequestBuilder[randomInt(30)];
-        IntIntMap values = new IntIntHashMap();
+        final Map<Integer, Integer> values = new HashMap<>();
         long missingValues = 0;
         for (int i = 0; i < builders.length; i++) {
             String name = "name_" + randomIntBetween(1, 10);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/EquivalenceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/EquivalenceIT.java
index d03b10ce092c9..2ffdf5fb32778 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/EquivalenceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/EquivalenceIT.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.search.aggregations;
 
-import com.carrotsearch.hppc.IntHashSet;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.RangeQueryBuilder;
 import org.opensearch.plugins.Plugin;
@@ -53,20 +56,24 @@
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregatorFactory;
 import org.opensearch.search.aggregations.metrics.Sum;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.After;
 import org.junit.Before;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Function;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.extendedStats;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -87,7 +94,24 @@
  * Additional tests that aim at testing more complex aggregation trees on larger random datasets, so that things like
  * the growth of dynamic arrays is tested.
  */
-public class EquivalenceIT extends OpenSearchIntegTestCase {
+public class EquivalenceIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public EquivalenceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -230,7 +254,7 @@ public void testDuelTerms() throws Exception {
         final int numDocs = scaledRandomIntBetween(1000, 2000);
         final int maxNumTerms = randomIntBetween(10, 5000);
 
-        final IntHashSet valuesSet = new IntHashSet();
+        final Set<Integer> valuesSet = new HashSet<>();
         cluster().wipeIndices("idx");
         prepareCreate("idx").setMapping(
             jsonBuilder().startObject()
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/FiltersAggsRewriteIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/FiltersAggsRewriteIT.java
index 3b8431c50a3ee..5926ff9f0cad1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/FiltersAggsRewriteIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/FiltersAggsRewriteIT.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.WrapperQueryBuilder;
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregator;
@@ -59,7 +59,7 @@ public void testWrapperQueryIsRewritten() throws IOException {
 
         XContentType xContentType = randomFrom(XContentType.values());
         BytesReference bytesReference;
-        try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType)) {
             builder.startObject();
             {
                 builder.startObject("terms");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MetadataIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MetadataIT.java
index f210af7c10fb3..1bc0cb36f5fe3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MetadataIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MetadataIT.java
@@ -32,25 +32,49 @@
 
 package org.opensearch.search.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.InternalBucketMetricValue;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.maxBucket;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 
-public class MetadataIT extends OpenSearchIntegTestCase {
+public class MetadataIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MetadataIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testMetadataSetOnAggregationResult() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("name", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MissingValueIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MissingValueIT.java
index 7d3f06760882d..e6325987d330f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MissingValueIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/MissingValueIT.java
@@ -32,22 +32,29 @@
 
 package org.opensearch.search.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregatorFactory.ExecutionMode;
 import org.opensearch.search.aggregations.metrics.Cardinality;
-import org.opensearch.search.aggregations.metrics.GeoBounds;
 import org.opensearch.search.aggregations.metrics.GeoCentroid;
 import org.opensearch.search.aggregations.metrics.Percentiles;
 import org.opensearch.search.aggregations.metrics.Stats;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.cardinality;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
-import static org.opensearch.search.aggregations.AggregationBuilders.geoBounds;
 import static org.opensearch.search.aggregations.AggregationBuilders.geoCentroid;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.percentiles;
@@ -58,7 +65,24 @@
 import static org.hamcrest.Matchers.closeTo;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class MissingValueIT extends OpenSearchIntegTestCase {
+public class MissingValueIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MissingValueIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected int maximumNumberOfShards() {
@@ -213,28 +237,6 @@ public void testStats() {
         assertEquals(4, stats.getAvg(), 0);
     }
 
-    public void testUnmappedGeoBounds() {
-        SearchResponse response = client().prepareSearch("idx")
-            .addAggregation(geoBounds("bounds").field("non_existing_field").missing("2,1"))
-            .get();
-        assertSearchResponse(response);
-        GeoBounds bounds = response.getAggregations().get("bounds");
-        assertThat(bounds.bottomRight().lat(), closeTo(2.0, 1E-5));
-        assertThat(bounds.bottomRight().lon(), closeTo(1.0, 1E-5));
-        assertThat(bounds.topLeft().lat(), closeTo(2.0, 1E-5));
-        assertThat(bounds.topLeft().lon(), closeTo(1.0, 1E-5));
-    }
-
-    public void testGeoBounds() {
-        SearchResponse response = client().prepareSearch("idx").addAggregation(geoBounds("bounds").field("location").missing("2,1")).get();
-        assertSearchResponse(response);
-        GeoBounds bounds = response.getAggregations().get("bounds");
-        assertThat(bounds.bottomRight().lat(), closeTo(1.0, 1E-5));
-        assertThat(bounds.bottomRight().lon(), closeTo(2.0, 1E-5));
-        assertThat(bounds.topLeft().lat(), closeTo(2.0, 1E-5));
-        assertThat(bounds.topLeft().lon(), closeTo(1.0, 1E-5));
-    }
-
     public void testGeoCentroid() {
         SearchResponse response = client().prepareSearch("idx")
             .addAggregation(geoCentroid("centroid").field("location").missing("2,1"))
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/AdjacencyMatrixIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/AdjacencyMatrixIT.java
index af3cc85ed40c0..cd0922606ec99 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/AdjacencyMatrixIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/AdjacencyMatrixIT.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
@@ -47,15 +50,19 @@
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.adjacencyMatrix;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -68,11 +75,28 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class AdjacencyMatrixIT extends OpenSearchIntegTestCase {
+public class AdjacencyMatrixIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int numDocs, numSingleTag1Docs, numSingleTag2Docs, numTag1Docs, numTag2Docs, numMultiTagDocs;
     static final int MAX_NUM_FILTERS = 3;
 
+    public AdjacencyMatrixIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/BooleanTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/BooleanTermsIT.java
index fc5407c4cade8..7ab1a44ce220c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/BooleanTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/BooleanTermsIT.java
@@ -31,26 +31,52 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class BooleanTermsIT extends OpenSearchIntegTestCase {
+public class BooleanTermsIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "b_value";
     private static final String MULTI_VALUED_FIELD_NAME = "b_values";
 
     static int numSingleTrues, numSingleFalses, numMultiTrues, numMultiFalses;
 
+    public BooleanTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramIT.java
index 782bcde39ce8d..4ce8af3e0f081 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramIT.java
@@ -31,16 +31,17 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.bootstrap.JavaVersion;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.common.time.DateMathParser;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -51,13 +52,14 @@
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
-import org.opensearch.search.aggregations.bucket.histogram.LongBounds;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
 import org.opensearch.search.aggregations.bucket.histogram.InternalDateHistogram;
+import org.opensearch.search.aggregations.bucket.histogram.LongBounds;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 import org.junit.After;
 
@@ -80,6 +82,7 @@
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -95,7 +98,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class DateHistogramIT extends OpenSearchIntegTestCase {
+public class DateHistogramIT extends ParameterizedOpenSearchIntegTestCase {
 
     static Map<ZonedDateTime, Map<String, Object>> expectedMultiSortBuckets;
 
@@ -103,6 +106,23 @@ private ZonedDateTime date(int month, int day) {
         return ZonedDateTime.of(2012, month, day, 0, 0, 0, 0, ZoneOffset.UTC);
     }
 
+    public DateHistogramIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private ZonedDateTime date(String date) {
         return DateFormatters.from(DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.parse(date));
     }
@@ -386,9 +406,6 @@ public void testSingleValued_timeZone_epoch() throws Exception {
             ZonedDateTime expectedKey = keyIterator.next();
             String bucketKey = bucket.getKeyAsString();
             String expectedBucketName = Long.toString(expectedKey.toInstant().toEpochMilli() / millisDivider);
-            if (JavaVersion.current().getVersion().get(0) == 8 && bucket.getKeyAsString().endsWith(".0")) {
-                expectedBucketName = expectedBucketName + ".0";
-            }
             assertThat(bucketKey, equalTo(expectedBucketName));
             assertThat(((ZonedDateTime) bucket.getKey()), equalTo(expectedKey));
             assertThat(bucket.getDocCount(), equalTo(1L));
@@ -1313,16 +1330,15 @@ public void testSingleValueFieldWithExtendedBoundsOffset() throws Exception {
     }
 
     public void testSingleValueWithMultipleDateFormatsFromMapping() throws Exception {
-        String mappingJson = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("date")
-                .field("type", "date")
-                .field("format", "strict_date_optional_time||dd-MM-yyyy")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mappingJson = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("date")
+            .field("type", "date")
+            .field("format", "strict_date_optional_time||dd-MM-yyyy")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         prepareCreate("idx2").setMapping(mappingJson).get();
         IndexRequestBuilder[] reqs = new IndexRequestBuilder[5];
         for (int i = 0; i < reqs.length; i++) {
@@ -1509,11 +1525,7 @@ public void testRewriteTimeZone_EpochMillisFormat() throws InterruptedException,
         assertSearchResponse(response);
         Histogram histo = response.getAggregations().get("histo");
         assertThat(histo.getBuckets().size(), equalTo(1));
-        if (JavaVersion.current().getVersion().get(0) == 8 && histo.getBuckets().get(0).getKeyAsString().endsWith(".0")) {
-            assertThat(histo.getBuckets().get(0).getKeyAsString(), equalTo("1477954800000.0"));
-        } else {
-            assertThat(histo.getBuckets().get(0).getKeyAsString(), equalTo("1477954800000"));
-        }
+        assertThat(histo.getBuckets().get(0).getKeyAsString(), equalTo("1477954800000"));
         assertThat(histo.getBuckets().get(0).getDocCount(), equalTo(1L));
 
         response = client().prepareSearch(index)
@@ -1743,6 +1755,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        cluster().wipeIndices("cache_test_idx");
     }
 
     public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscAndKeyDesc() throws Exception {
@@ -1860,6 +1873,7 @@ public void testDateNanosHistogram() throws Exception {
         assertEquals(1, buckets.get(0).getDocCount());
         assertEquals(946771200000L, ((ZonedDateTime) buckets.get(1).getKey()).toEpochSecond() * 1000);
         assertEquals(1, buckets.get(1).getDocCount());
+        cluster().wipeIndices("nanos");
     }
 
     public void testDateKeyFormatting() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramOffsetIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramOffsetIT.java
index 19e5bdb8916b8..04115f69172da 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramOffsetIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateHistogramOffsetIT.java
@@ -31,24 +31,32 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateFormatters;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.After;
 import org.junit.Before;
 
 import java.io.IOException;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.core.IsNull.notNullValue;
@@ -61,11 +69,28 @@
  */
 @OpenSearchIntegTestCase.SuiteScopeTestCase
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class DateHistogramOffsetIT extends OpenSearchIntegTestCase {
+public class DateHistogramOffsetIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String DATE_FORMAT = "yyyy-MM-dd:hh-mm-ss";
     private static final DateFormatter FORMATTER = DateFormatter.forPattern(DATE_FORMAT);
 
+    public DateHistogramOffsetIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private ZonedDateTime date(String date) {
         return DateFormatters.from(DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.parse(date));
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateRangeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateRangeIT.java
index 470ee6a4d2cea..ae4243019ffb1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateRangeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DateRangeIT.java
@@ -31,11 +31,14 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -46,6 +49,7 @@
 import org.opensearch.search.aggregations.bucket.range.Range.Bucket;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.time.ZoneId;
@@ -63,6 +67,7 @@
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateRange;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
@@ -76,7 +81,24 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class DateRangeIT extends OpenSearchIntegTestCase {
+public class DateRangeIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public DateRangeIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     private static IndexRequestBuilder indexDoc(int month, int day, int value) throws Exception {
         return client().prepareIndex("idx")
@@ -1062,6 +1084,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     /**
@@ -1124,6 +1147,7 @@ public void testRangeWithFormatStringValue() throws Exception {
                 .get()
         );
         assertThat(e.getDetailedMessage(), containsString("failed to parse date field [1000000] with format [strict_hour_minute_second]"));
+        internalCluster().wipeIndices(indexName);
     }
 
     /**
@@ -1196,6 +1220,7 @@ public void testRangeWithFormatNumericValue() throws Exception {
         buckets = checkBuckets(searchResponse.getAggregations().get("date_range"), "date_range", 2);
         assertBucket(buckets.get(0), 2L, "1000000-3000000", 1000000L, 3000000L);
         assertBucket(buckets.get(1), 1L, "3000000-4000000", 3000000L, 4000000L);
+        internalCluster().wipeIndices(indexName);
     }
 
     private static List<Range.Bucket> checkBuckets(Range dateRange, String expectedAggName, long expectedBucketsSize) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DiversifiedSamplerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DiversifiedSamplerIT.java
index 5b01e7573908c..5e95073209c71 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DiversifiedSamplerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DiversifiedSamplerIT.java
@@ -31,11 +31,15 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.sampler.DiversifiedAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.sampler.Sampler;
 import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregator;
@@ -43,14 +47,16 @@
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.Max;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
 import static org.opensearch.search.aggregations.AggregationBuilders.sampler;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -65,10 +71,27 @@
  * Tests the Sampler aggregation
  */
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class DiversifiedSamplerIT extends OpenSearchIntegTestCase {
+public class DiversifiedSamplerIT extends ParameterizedOpenSearchIntegTestCase {
 
     public static final int NUM_SHARDS = 2;
 
+    public DiversifiedSamplerIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public String randomExecutionHint() {
         return randomBoolean() ? null : randomFrom(SamplerAggregator.ExecutionMode.values()).toString();
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DoubleTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DoubleTermsIT.java
index 3093c7490a2a5..88bb41923e53f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DoubleTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/DoubleTermsIT.java
@@ -48,9 +48,9 @@
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.metrics.Avg;
+import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.Max;
 import org.opensearch.search.aggregations.metrics.Stats;
-import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
@@ -88,6 +88,10 @@
 @OpenSearchIntegTestCase.SuiteScopeTestCase
 public class DoubleTermsIT extends AbstractTermsTestCase {
 
+    public DoubleTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -1106,5 +1110,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FilterIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FilterIT.java
index 0845db4f332d7..7aa98803403e0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FilterIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FilterIT.java
@@ -31,10 +31,14 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -42,14 +46,18 @@
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -60,10 +68,27 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class FilterIT extends OpenSearchIntegTestCase {
+public class FilterIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int numDocs, numTag1Docs;
 
+    public FilterIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FiltersIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FiltersIT.java
index a64fe61b29b8a..b6cf515df78ba 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FiltersIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/FiltersIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -44,6 +48,7 @@
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
@@ -56,6 +61,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.filters;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -66,10 +72,27 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class FiltersIT extends OpenSearchIntegTestCase {
+public class FiltersIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int numDocs, numTag1Docs, numTag2Docs, numOtherDocs;
 
+    public FiltersIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoDistanceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoDistanceIT.java
index 603a141abcaec..bfacbc1c17a3c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoDistanceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoDistanceIT.java
@@ -31,6 +31,8 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.Version;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
@@ -39,7 +41,8 @@
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
@@ -47,17 +50,20 @@
 import org.opensearch.search.aggregations.bucket.range.Range.Bucket;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.geoDistance;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -70,7 +76,11 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class GeoDistanceIT extends OpenSearchIntegTestCase {
+public class GeoDistanceIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public GeoDistanceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
 
     @Override
     protected boolean forbidPrivateIndexSettings() {
@@ -79,6 +89,19 @@ protected boolean forbidPrivateIndexSettings() {
 
     private Version version = VersionUtils.randomIndexCompatibleVersion(random());
 
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private IndexRequestBuilder indexCity(String idx, String name, String... latLons) throws Exception {
         XContentBuilder source = jsonBuilder().startObject().field("city", name);
         source.startArray("location");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoHashGridIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoHashGridIT.java
deleted file mode 100644
index 56d918feef9d8..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoHashGridIT.java
+++ /dev/null
@@ -1,317 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.bucket;
-
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.ObjectIntMap;
-import com.carrotsearch.hppc.cursors.ObjectIntCursor;
-import org.opensearch.Version;
-import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.action.search.SearchResponse;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.query.GeoBoundingBoxQueryBuilder;
-import org.opensearch.search.aggregations.AggregationBuilders;
-import org.opensearch.search.aggregations.InternalAggregation;
-import org.opensearch.search.aggregations.bucket.filter.Filter;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGrid;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGrid.Bucket;
-import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.VersionUtils;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Random;
-import java.util.Set;
-
-import static org.opensearch.geometry.utils.Geohash.PRECISION;
-import static org.opensearch.geometry.utils.Geohash.stringEncode;
-import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.search.aggregations.AggregationBuilders.geohashGrid;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-
-@OpenSearchIntegTestCase.SuiteScopeTestCase
-public class GeoHashGridIT extends OpenSearchIntegTestCase {
-
-    @Override
-    protected boolean forbidPrivateIndexSettings() {
-        return false;
-    }
-
-    private Version version = VersionUtils.randomIndexCompatibleVersion(random());
-
-    static ObjectIntMap<String> expectedDocCountsForGeoHash = null;
-    static ObjectIntMap<String> multiValuedExpectedDocCountsForGeoHash = null;
-    static int numDocs = 100;
-
-    static String smallestGeoHash = null;
-
-    private static IndexRequestBuilder indexCity(String index, String name, List<String> latLon) throws Exception {
-        XContentBuilder source = jsonBuilder().startObject().field("city", name);
-        if (latLon != null) {
-            source = source.field("location", latLon);
-        }
-        source = source.endObject();
-        return client().prepareIndex(index).setSource(source);
-    }
-
-    private static IndexRequestBuilder indexCity(String index, String name, String latLon) throws Exception {
-        return indexCity(index, name, Arrays.<String>asList(latLon));
-    }
-
-    @Override
-    public void setupSuiteScopeCluster() throws Exception {
-        createIndex("idx_unmapped");
-
-        Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, version).build();
-
-        assertAcked(prepareCreate("idx").setSettings(settings).setMapping("location", "type=geo_point", "city", "type=keyword"));
-
-        List<IndexRequestBuilder> cities = new ArrayList<>();
-        Random random = random();
-        expectedDocCountsForGeoHash = new ObjectIntHashMap<>(numDocs * 2);
-        for (int i = 0; i < numDocs; i++) {
-            // generate random point
-            double lat = (180d * random.nextDouble()) - 90d;
-            double lng = (360d * random.nextDouble()) - 180d;
-            String randomGeoHash = stringEncode(lng, lat, PRECISION);
-            // Index at the highest resolution
-            cities.add(indexCity("idx", randomGeoHash, lat + ", " + lng));
-            expectedDocCountsForGeoHash.put(randomGeoHash, expectedDocCountsForGeoHash.getOrDefault(randomGeoHash, 0) + 1);
-            // Update expected doc counts for all resolutions..
-            for (int precision = PRECISION - 1; precision > 0; precision--) {
-                String hash = stringEncode(lng, lat, precision);
-                if ((smallestGeoHash == null) || (hash.length() < smallestGeoHash.length())) {
-                    smallestGeoHash = hash;
-                }
-                expectedDocCountsForGeoHash.put(hash, expectedDocCountsForGeoHash.getOrDefault(hash, 0) + 1);
-            }
-        }
-        indexRandom(true, cities);
-
-        assertAcked(
-            prepareCreate("multi_valued_idx").setSettings(settings).setMapping("location", "type=geo_point", "city", "type=keyword")
-        );
-
-        cities = new ArrayList<>();
-        multiValuedExpectedDocCountsForGeoHash = new ObjectIntHashMap<>(numDocs * 2);
-        for (int i = 0; i < numDocs; i++) {
-            final int numPoints = random.nextInt(4);
-            List<String> points = new ArrayList<>();
-            Set<String> geoHashes = new HashSet<>();
-            for (int j = 0; j < numPoints; ++j) {
-                double lat = (180d * random.nextDouble()) - 90d;
-                double lng = (360d * random.nextDouble()) - 180d;
-                points.add(lat + "," + lng);
-                // Update expected doc counts for all resolutions..
-                for (int precision = PRECISION; precision > 0; precision--) {
-                    final String geoHash = stringEncode(lng, lat, precision);
-                    geoHashes.add(geoHash);
-                }
-            }
-            cities.add(indexCity("multi_valued_idx", Integer.toString(i), points));
-            for (String hash : geoHashes) {
-                multiValuedExpectedDocCountsForGeoHash.put(hash, multiValuedExpectedDocCountsForGeoHash.getOrDefault(hash, 0) + 1);
-            }
-        }
-        indexRandom(true, cities);
-
-        ensureSearchable();
-    }
-
-    public void testSimple() throws Exception {
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("idx")
-                .addAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
-                .get();
-
-            assertSearchResponse(response);
-
-            GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
-            List<? extends Bucket> buckets = geoGrid.getBuckets();
-            Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
-            Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
-            for (int i = 0; i < buckets.size(); i++) {
-                GeoGrid.Bucket cell = buckets.get(i);
-                String geohash = cell.getKeyAsString();
-
-                long bucketCount = cell.getDocCount();
-                int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
-                assertNotSame(bucketCount, 0);
-                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
-                GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
-                assertThat(stringEncode(geoPoint.lon(), geoPoint.lat(), precision), equalTo(geohash));
-                assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
-            }
-        }
-    }
-
-    public void testMultivalued() throws Exception {
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("multi_valued_idx")
-                .addAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
-                .get();
-
-            assertSearchResponse(response);
-
-            GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
-            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
-                String geohash = cell.getKeyAsString();
-
-                long bucketCount = cell.getDocCount();
-                int expectedBucketCount = multiValuedExpectedDocCountsForGeoHash.get(geohash);
-                assertNotSame(bucketCount, 0);
-                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
-            }
-        }
-    }
-
-    public void testFiltered() throws Exception {
-        GeoBoundingBoxQueryBuilder bbox = new GeoBoundingBoxQueryBuilder("location");
-        bbox.setCorners(smallestGeoHash).queryName("bbox");
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("idx")
-                .addAggregation(
-                    AggregationBuilders.filter("filtered", bbox)
-                        .subAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
-                )
-                .get();
-
-            assertSearchResponse(response);
-
-            Filter filter = response.getAggregations().get("filtered");
-
-            GeoGrid geoGrid = filter.getAggregations().get("geohashgrid");
-            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
-                String geohash = cell.getKeyAsString();
-                long bucketCount = cell.getDocCount();
-                int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
-                assertNotSame(bucketCount, 0);
-                assertTrue("Buckets must be filtered", geohash.startsWith(smallestGeoHash));
-                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
-
-            }
-        }
-    }
-
-    public void testUnmapped() throws Exception {
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("idx_unmapped")
-                .addAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
-                .get();
-
-            assertSearchResponse(response);
-
-            GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
-            assertThat(geoGrid.getBuckets().size(), equalTo(0));
-        }
-
-    }
-
-    public void testPartiallyUnmapped() throws Exception {
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("idx", "idx_unmapped")
-                .addAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
-                .get();
-
-            assertSearchResponse(response);
-
-            GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
-            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
-                String geohash = cell.getKeyAsString();
-
-                long bucketCount = cell.getDocCount();
-                int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
-                assertNotSame(bucketCount, 0);
-                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
-            }
-        }
-    }
-
-    public void testTopMatch() throws Exception {
-        for (int precision = 1; precision <= PRECISION; precision++) {
-            SearchResponse response = client().prepareSearch("idx")
-                .addAggregation(geohashGrid("geohashgrid").field("location").size(1).shardSize(100).precision(precision))
-                .get();
-
-            assertSearchResponse(response);
-
-            GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
-            // Check we only have one bucket with the best match for that resolution
-            assertThat(geoGrid.getBuckets().size(), equalTo(1));
-            for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
-                String geohash = cell.getKeyAsString();
-                long bucketCount = cell.getDocCount();
-                int expectedBucketCount = 0;
-                for (ObjectIntCursor<String> cursor : expectedDocCountsForGeoHash) {
-                    if (cursor.key.length() == precision) {
-                        expectedBucketCount = Math.max(expectedBucketCount, cursor.value);
-                    }
-                }
-                assertNotSame(bucketCount, 0);
-                assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
-            }
-        }
-    }
-
-    public void testSizeIsZero() {
-        final int size = 0;
-        final int shardSize = 10000;
-        IllegalArgumentException exception = expectThrows(
-            IllegalArgumentException.class,
-            () -> client().prepareSearch("idx")
-                .addAggregation(geohashGrid("geohashgrid").field("location").size(size).shardSize(shardSize))
-                .get()
-        );
-        assertThat(exception.getMessage(), containsString("[size] must be greater than 0. Found [0] in [geohashgrid]"));
-    }
-
-    public void testShardSizeIsZero() {
-        final int size = 100;
-        final int shardSize = 0;
-        IllegalArgumentException exception = expectThrows(
-            IllegalArgumentException.class,
-            () -> client().prepareSearch("idx")
-                .addAggregation(geohashGrid("geohashgrid").field("location").size(size).shardSize(shardSize))
-                .get()
-        );
-        assertThat(exception.getMessage(), containsString("[shardSize] must be greater than 0. Found [0] in [geohashgrid]"));
-    }
-
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GlobalIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GlobalIT.java
index 46e5fb7332e89..be31a3afadad0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GlobalIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GlobalIT.java
@@ -31,19 +31,27 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.metrics.Stats;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.stats;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
@@ -53,10 +61,27 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class GlobalIT extends OpenSearchIntegTestCase {
+public class GlobalIT extends ParameterizedOpenSearchIntegTestCase {
 
     static int numDocs;
 
+    public GlobalIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
@@ -83,10 +108,19 @@ public void setupSuiteScopeCluster() throws Exception {
         ensureSearchable();
     }
 
-    public void testWithStatsSubAggregator() throws Exception {
+    public void testWithStatsSubAggregatorAndProfileEnabled() throws Exception {
+        testWithStatsSubAggregator(true);
+    }
+
+    public void testWithStatsSubAggregatorAndProfileDisabled() throws Exception {
+        testWithStatsSubAggregator(false);
+    }
+
+    private void testWithStatsSubAggregator(boolean profileEnabled) throws Exception {
         SearchResponse response = client().prepareSearch("idx")
             .setQuery(QueryBuilders.termQuery("tag", "tag1"))
             .addAggregation(global("global").subAggregation(stats("value_stats").field("value")))
+            .setProfile(profileEnabled)
             .get();
 
         assertSearchResponse(response);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/HistogramIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/HistogramIT.java
index dae788abe0d10..75f57d1cc4c0e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/HistogramIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/HistogramIT.java
@@ -31,18 +31,21 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import com.carrotsearch.hppc.LongHashSet;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationExecutionException;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.histogram.DoubleBounds;
@@ -52,22 +55,26 @@
 import org.opensearch.search.aggregations.metrics.Max;
 import org.opensearch.search.aggregations.metrics.Stats;
 import org.opensearch.search.aggregations.metrics.Sum;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Function;
 
 import static java.util.Collections.emptyMap;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -84,7 +91,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class HistogramIT extends OpenSearchIntegTestCase {
+public class HistogramIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
     private static final String MULTI_VALUED_FIELD_NAME = "l_values";
@@ -95,6 +102,23 @@ public class HistogramIT extends OpenSearchIntegTestCase {
     static long[] valueCounts, valuesCounts;
     static Map<Long, Map<String, Object>> expectedMultiSortBuckets;
 
+    public HistogramIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -396,7 +420,7 @@ public void testSingleValuedFieldOrderedByCountAsc() throws Exception {
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet buckets = new LongHashSet();
+        final Set<Long> buckets = new HashSet<>();
         List<Histogram.Bucket> histoBuckets = new ArrayList<>(histo.getBuckets());
         long previousCount = Long.MIN_VALUE;
         for (int i = 0; i < numValueBuckets; ++i) {
@@ -423,7 +447,7 @@ public void testSingleValuedFieldOrderedByCountDesc() throws Exception {
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet buckets = new LongHashSet();
+        final Set<Long> buckets = new HashSet<>();
         List<Histogram.Bucket> histoBuckets = new ArrayList<>(histo.getBuckets());
         long previousCount = Long.MAX_VALUE;
         for (int i = 0; i < numValueBuckets; ++i) {
@@ -497,7 +521,7 @@ public void testSingleValuedFieldOrderedBySubAggregationAsc() throws Exception {
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet visited = new LongHashSet();
+        final Set<Long> visited = new HashSet<>();
         double previousSum = Double.NEGATIVE_INFINITY;
         List<Histogram.Bucket> buckets = new ArrayList<>(histo.getBuckets());
         for (int i = 0; i < numValueBuckets; ++i) {
@@ -539,7 +563,7 @@ public void testSingleValuedFieldOrderedBySubAggregationDesc() throws Exception
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet visited = new LongHashSet();
+        final Set<Long> visited = new HashSet<>();
         double previousSum = Double.POSITIVE_INFINITY;
         List<Histogram.Bucket> buckets = new ArrayList<>(histo.getBuckets());
         for (int i = 0; i < numValueBuckets; ++i) {
@@ -581,7 +605,7 @@ public void testSingleValuedFieldOrderedByMultiValuedSubAggregationDesc() throws
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet visited = new LongHashSet();
+        final Set<Long> visited = new HashSet<>();
         double previousSum = Double.POSITIVE_INFINITY;
 
         List<Histogram.Bucket> buckets = new ArrayList<>(histo.getBuckets());
@@ -625,7 +649,7 @@ public void testSingleValuedFieldOrderedBySubAggregationDescDeepOrderPath() thro
         assertThat(histo.getName(), equalTo("histo"));
         assertThat(histo.getBuckets().size(), equalTo(numValueBuckets));
 
-        LongHashSet visited = new LongHashSet();
+        final Set<Long> visited = new HashSet<>();
         double prevMax = asc ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
         List<Histogram.Bucket> buckets = new ArrayList<>(histo.getBuckets());
         for (int i = 0; i < numValueBuckets; ++i) {
@@ -1143,6 +1167,7 @@ public void testDecimalIntervalAndOffset() throws Exception {
         assertEquals(1, buckets.get(0).getDocCount());
         assertEquals(0.05, (double) buckets.get(1).getKey(), 0.01d);
         assertEquals(1, buckets.get(1).getDocCount());
+        internalCluster().wipeIndices("decimal_values");
     }
 
     /**
@@ -1284,6 +1309,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscAndKeyDesc() throws Exception {
@@ -1387,6 +1413,7 @@ public void testHardBounds() throws Exception {
         buckets = histogram.getBuckets();
         assertEquals(1, buckets.size());
         assertEquals(0.1, (double) buckets.get(0).getKey(), 0.01d);
+        internalCluster().wipeIndices("test");
 
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpRangeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpRangeIT.java
index f8f666aaa3c1b..14a3685bd183e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpRangeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpRangeIT.java
@@ -31,9 +31,13 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
@@ -41,6 +45,7 @@
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.aggregations.bucket.range.Range;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -48,13 +53,31 @@
 import java.util.Map;
 import java.util.function.Function;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.instanceOf;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class IpRangeIT extends OpenSearchIntegTestCase {
+public class IpRangeIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public IpRangeIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public static class DummyScriptPlugin extends MockScriptPlugin {
         @Override
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpTermsIT.java
index cff51e74fdbd0..c712c97af5c71 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/IpTermsIT.java
@@ -32,6 +32,7 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
@@ -50,6 +51,10 @@
 
 public class IpTermsIT extends AbstractTermsTestCase {
 
+    public IpTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/LongTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/LongTermsIT.java
index 87968bd2117c6..41cf0529f78f5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/LongTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/LongTermsIT.java
@@ -48,9 +48,9 @@
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.metrics.Avg;
+import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.Max;
 import org.opensearch.search.aggregations.metrics.Stats;
-import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
@@ -86,6 +86,10 @@
 @OpenSearchIntegTestCase.SuiteScopeTestCase
 public class LongTermsIT extends AbstractTermsTestCase {
 
+    public LongTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -1054,5 +1058,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MinDocCountIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MinDocCountIT.java
index 08e696245209e..90dafc0d57887 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MinDocCountIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MinDocCountIT.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import com.carrotsearch.hppc.LongHashSet;
-import com.carrotsearch.hppc.LongSet;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.query.QueryBuilder;
@@ -82,6 +82,10 @@ public class MinDocCountIT extends AbstractTermsTestCase {
     private static final QueryBuilder QUERY = QueryBuilders.termQuery("match", true);
     private static int cardinality;
 
+    public MinDocCountIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -122,7 +126,7 @@ public void setupSuiteScopeCluster() throws Exception {
         cardinality = randomIntBetween(8, 30);
         final List<IndexRequestBuilder> indexRequests = new ArrayList<>();
         final Set<String> stringTerms = new HashSet<>();
-        final LongSet longTerms = new LongHashSet();
+        final Set<Long> longTerms = new HashSet();
         for (int i = 0; i < cardinality; ++i) {
             String stringTerm;
             do {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MultiTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MultiTermsIT.java
new file mode 100644
index 0000000000000..8d79f581a0ab4
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/MultiTermsIT.java
@@ -0,0 +1,172 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptType;
+import org.opensearch.search.aggregations.bucket.terms.BaseStringTermsTestCase;
+import org.opensearch.search.aggregations.bucket.terms.StringTermsIT;
+import org.opensearch.search.aggregations.bucket.terms.Terms;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValueType;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Collections;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.search.aggregations.AggregationBuilders.multiTerms;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.core.IsNull.notNullValue;
+
+/**
+ * Extend {@link BaseStringTermsTestCase}.
+ */
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class MultiTermsIT extends BaseStringTermsTestCase {
+
+    public MultiTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    // the main purpose of this test is to make sure we're not allocating 2GB of memory per shard
+    public void testSizeIsZero() {
+        final int minDocCount = randomInt(1);
+        IllegalArgumentException exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().prepareSearch("high_card_idx")
+                .addAggregation(
+                    multiTerms("mterms").terms(
+                        asList(
+                            new MultiTermsValuesSourceConfig.Builder().setFieldName(SINGLE_VALUED_FIELD_NAME).build(),
+                            new MultiTermsValuesSourceConfig.Builder().setFieldName(MULTI_VALUED_FIELD_NAME).build()
+                        )
+                    ).minDocCount(minDocCount).size(0)
+                )
+                .get()
+        );
+        assertThat(exception.getMessage(), containsString("[size] must be greater than 0. Found [0] in [mterms]"));
+    }
+
+    public void testSingleValuedFieldWithValueScript() throws Exception {
+        SearchResponse response = client().prepareSearch("idx")
+            .addAggregation(
+                multiTerms("mterms").terms(
+                    asList(
+                        new MultiTermsValuesSourceConfig.Builder().setFieldName("i").build(),
+                        new MultiTermsValuesSourceConfig.Builder().setFieldName(SINGLE_VALUED_FIELD_NAME)
+                            .setScript(
+                                new Script(
+                                    ScriptType.INLINE,
+                                    StringTermsIT.CustomScriptPlugin.NAME,
+                                    "'foo_' + _value",
+                                    Collections.emptyMap()
+                                )
+                            )
+                            .build()
+                    )
+                )
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        Terms terms = response.getAggregations().get("mterms");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getName(), equalTo("mterms"));
+        assertThat(terms.getBuckets().size(), equalTo(5));
+
+        for (int i = 0; i < 5; i++) {
+            Terms.Bucket bucket = terms.getBucketByKey(i + "|foo_val" + i);
+            assertThat(bucket, notNullValue());
+            assertThat(key(bucket), equalTo(i + "|foo_val" + i));
+            assertThat(bucket.getDocCount(), equalTo(1L));
+        }
+    }
+
+    public void testSingleValuedFieldWithScript() throws Exception {
+        SearchResponse response = client().prepareSearch("idx")
+            .addAggregation(
+                multiTerms("mterms").terms(
+                    asList(
+                        new MultiTermsValuesSourceConfig.Builder().setFieldName("i").build(),
+                        new MultiTermsValuesSourceConfig.Builder().setScript(
+                            new Script(
+                                ScriptType.INLINE,
+                                StringTermsIT.CustomScriptPlugin.NAME,
+                                "doc['" + SINGLE_VALUED_FIELD_NAME + "'].value",
+                                Collections.emptyMap()
+                            )
+                        ).setUserValueTypeHint(ValueType.STRING).build()
+                    )
+                )
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        Terms terms = response.getAggregations().get("mterms");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getName(), equalTo("mterms"));
+        assertThat(terms.getBuckets().size(), equalTo(5));
+
+        for (int i = 0; i < 5; i++) {
+            Terms.Bucket bucket = terms.getBucketByKey(i + "|val" + i);
+            assertThat(bucket, notNullValue());
+            assertThat(key(bucket), equalTo(i + "|val" + i));
+            assertThat(bucket.getDocCount(), equalTo(1L));
+        }
+    }
+
+    public void testMultiValuedFieldWithValueScript() throws Exception {
+        SearchResponse response = client().prepareSearch("idx")
+            .addAggregation(
+                multiTerms("mterms").terms(
+                    asList(
+                        new MultiTermsValuesSourceConfig.Builder().setFieldName("tag").build(),
+                        new MultiTermsValuesSourceConfig.Builder().setFieldName(MULTI_VALUED_FIELD_NAME)
+                            .setScript(
+                                new Script(
+                                    ScriptType.INLINE,
+                                    StringTermsIT.CustomScriptPlugin.NAME,
+                                    "_value.substring(0,3)",
+                                    Collections.emptyMap()
+                                )
+                            )
+                            .build()
+                    )
+                )
+            )
+            .get();
+
+        assertSearchResponse(response);
+
+        Terms terms = response.getAggregations().get("mterms");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getName(), equalTo("mterms"));
+        assertThat(terms.getBuckets().size(), equalTo(2));
+
+        Terms.Bucket bucket = terms.getBucketByKey("more|val");
+        assertThat(bucket, notNullValue());
+        assertThat(key(bucket), equalTo("more|val"));
+        assertThat(bucket.getDocCount(), equalTo(3L));
+
+        bucket = terms.getBucketByKey("less|val");
+        assertThat(bucket, notNullValue());
+        assertThat(key(bucket), equalTo("less|val"));
+        assertThat(bucket.getDocCount(), equalTo(2L));
+    }
+
+    private MultiTermsValuesSourceConfig field(String name) {
+        return new MultiTermsValuesSourceConfig.Builder().setFieldName(name).build();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NaNSortingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NaNSortingIT.java
index 3a3e02c577096..1ef2c0e8db8c7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NaNSortingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NaNSortingIT.java
@@ -32,23 +32,32 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.Comparators;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.search.aggregations.metrics.AvgAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.ExtendedStatsAggregationBuilder;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.extendedStats;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -58,7 +67,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class NaNSortingIT extends OpenSearchIntegTestCase {
+public class NaNSortingIT extends ParameterizedOpenSearchIntegTestCase {
 
     private enum SubAggregation {
         AVG("avg") {
@@ -130,6 +139,23 @@ public String sortKey() {
         public abstract double getValue(Aggregation aggregation);
     }
 
+    public NaNSortingIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("string_value", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NestedIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NestedIT.java
index fcde2f628ecd7..b3009ffcf4f45 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NestedIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/NestedIT.java
@@ -31,17 +31,19 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.apache.lucene.search.join.ScoreMode;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
+import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
@@ -55,10 +57,12 @@
 import org.opensearch.search.aggregations.metrics.Stats;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
@@ -68,6 +72,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.nestedQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
@@ -87,12 +92,29 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class NestedIT extends OpenSearchIntegTestCase {
+public class NestedIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static int numParents;
     private static int[] numChildren;
     private static SubAggCollectionMode aggCollectionMode;
 
+    public NestedIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
 
@@ -461,7 +483,7 @@ public void testParentFilterResolvedCorrectly() throws Exception {
                     "{\"dates\": {\"month\": {\"label\": \"2014-11\", \"end\": \"2014-11-30\", \"start\": \"2014-11-01\"}, "
                         + "\"day\": \"2014-11-30\"}, \"comments\": [{\"cid\": 3,\"identifier\": \"29111\"}, {\"cid\": 4,\"tags\": ["
                         + "{\"tid\" :44,\"name\": \"Roles\"}], \"identifier\": \"29101\"}]}",
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
         indexRequests.add(
@@ -471,7 +493,7 @@ public void testParentFilterResolvedCorrectly() throws Exception {
                     "{\"dates\": {\"month\": {\"label\": \"2014-12\", \"end\": \"2014-12-31\", \"start\": \"2014-12-01\"}, "
                         + "\"day\": \"2014-12-03\"}, \"comments\": [{\"cid\": 1, \"identifier\": \"29111\"}, {\"cid\": 2,\"tags\": ["
                         + "{\"tid\" : 22, \"name\": \"DataChannels\"}], \"identifier\": \"29101\"}]}",
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
         indexRandom(true, indexRequests);
@@ -534,6 +556,7 @@ public void testParentFilterResolvedCorrectly() throws Exception {
         assertThat(nestedTags.getDocCount(), equalTo(0L)); // This must be 0
         tags = nestedTags.getAggregations().get("tag");
         assertThat(tags.getBuckets().size(), equalTo(0)); // and this must be empty
+        internalCluster().wipeIndices("idx2");
     }
 
     public void testNestedSameDocIdProcessedMultipleTime() throws Exception {
@@ -640,6 +663,7 @@ public void testNestedSameDocIdProcessedMultipleTime() throws Exception {
         assertThat(propertyId.getBucketByKey("1").getDocCount(), equalTo(1L));
         assertThat(propertyId.getBucketByKey("2").getDocCount(), equalTo(1L));
         assertThat(propertyId.getBucketByKey("3").getDocCount(), equalTo(1L));
+        internalCluster().wipeIndices("idx4");
     }
 
     public void testFilterAggInsideNestedAgg() throws Exception {
@@ -802,6 +826,7 @@ public void testFilterAggInsideNestedAgg() throws Exception {
         assertThat(bucket.getDocCount(), equalTo(1L));
         numStringParams = bucket.getAggregations().get("num_string_params");
         assertThat(numStringParams.getDocCount(), equalTo(0L));
+        internalCluster().wipeIndices("classes");
     }
 
     public void testExtractInnerHitBuildersWithDuplicateHitName() throws Exception {
@@ -826,6 +851,7 @@ public void testExtractInnerHitBuildersWithDuplicateHitName() throws Exception {
             RestStatus.BAD_REQUEST,
             containsString("[inner_hits] already contains an entry for key [ih1]")
         );
+        internalCluster().wipeIndices("idxduplicatehitnames");
     }
 
     public void testExtractInnerHitBuildersWithDuplicatePath() throws Exception {
@@ -848,5 +874,6 @@ public void testExtractInnerHitBuildersWithDuplicatePath() throws Exception {
             RestStatus.BAD_REQUEST,
             containsString("[inner_hits] already contains an entry for key [property]")
         );
+        internalCluster().wipeIndices("idxnullhitnames");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/RangeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/RangeIT.java
index c46d6dcd847e1..64ab6f1382ac3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/RangeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/RangeIT.java
@@ -31,10 +31,13 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
@@ -48,9 +51,11 @@
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -60,6 +65,7 @@
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.range;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
@@ -73,13 +79,30 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class RangeIT extends OpenSearchIntegTestCase {
+public class RangeIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
     private static final String MULTI_VALUED_FIELD_NAME = "l_values";
 
     static int numDocs;
 
+    public RangeIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -1061,6 +1084,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testFieldAlias() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ReverseNestedIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ReverseNestedIT.java
index 67ae145aece11..2716db6b7e745 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ReverseNestedIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ReverseNestedIT.java
@@ -31,22 +31,27 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.nested.Nested;
 import org.opensearch.search.aggregations.bucket.nested.ReverseNested;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.ValueCount;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
@@ -55,6 +60,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.count;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.nested;
@@ -70,7 +76,24 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class ReverseNestedIT extends OpenSearchIntegTestCase {
+public class ReverseNestedIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ReverseNestedIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     public void setupSuiteScopeCluster() throws Exception {
@@ -726,6 +749,7 @@ public void testSameParentDocHavingMultipleBuckets() throws Exception {
             ValueCount barCount = reverseToBar.getAggregations().get("sku_count");
             assertThat(barCount.getValue(), equalTo(2L));
         }
+        internalCluster().wipeIndices("idx3");
     }
 
     public void testFieldAlias() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SamplerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SamplerIT.java
index 0bfeff9297ce8..7033c42c5d661 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SamplerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SamplerIT.java
@@ -32,24 +32,31 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.sampler.Sampler;
-import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregator;
 import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregator;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.metrics.Max;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
 import static org.opensearch.search.aggregations.AggregationBuilders.sampler;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -64,7 +71,7 @@
  * Tests the Sampler aggregation
  */
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class SamplerIT extends OpenSearchIntegTestCase {
+public class SamplerIT extends ParameterizedOpenSearchIntegTestCase {
 
     public static final int NUM_SHARDS = 2;
 
@@ -72,6 +79,23 @@ public String randomExecutionHint() {
         return randomBoolean() ? null : randomFrom(SamplerAggregator.ExecutionMode.values()).toString();
     }
 
+    public SamplerIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardReduceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardReduceIT.java
index 7352dc7170a21..66d761c56634e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardReduceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardReduceIT.java
@@ -31,13 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGrid;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
@@ -46,13 +49,16 @@
 import org.opensearch.search.aggregations.bucket.range.Range;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateRange;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
-import static org.opensearch.search.aggregations.AggregationBuilders.geohashGrid;
-import static org.opensearch.search.aggregations.AggregationBuilders.geotileGrid;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.ipRange;
@@ -71,7 +77,24 @@
  * we can make sure that the reduce is properly propagated by checking that empty buckets were created.
  */
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class ShardReduceIT extends OpenSearchIntegTestCase {
+public class ShardReduceIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ShardReduceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     private IndexRequestBuilder indexDoc(String date, int value) throws Exception {
         return client().prepareIndex("idx")
@@ -338,36 +361,4 @@ public void testDateHistogram() throws Exception {
 
     }
 
-    public void testGeoHashGrid() throws Exception {
-        SearchResponse response = client().prepareSearch("idx")
-            .setQuery(QueryBuilders.matchAllQuery())
-            .addAggregation(
-                geohashGrid("grid").field("location")
-                    .subAggregation(dateHistogram("histo").field("date").dateHistogramInterval(DateHistogramInterval.DAY).minDocCount(0))
-            )
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoGrid grid = response.getAggregations().get("grid");
-        Histogram histo = grid.getBuckets().iterator().next().getAggregations().get("histo");
-        assertThat(histo.getBuckets().size(), equalTo(4));
-    }
-
-    public void testGeoTileGrid() throws Exception {
-        SearchResponse response = client().prepareSearch("idx")
-            .setQuery(QueryBuilders.matchAllQuery())
-            .addAggregation(
-                geotileGrid("grid").field("location")
-                    .subAggregation(dateHistogram("histo").field("date").dateHistogramInterval(DateHistogramInterval.DAY).minDocCount(0))
-            )
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoGrid grid = response.getAggregations().get("grid");
-        Histogram histo = grid.getBuckets().iterator().next().getAggregations().get("histo");
-        assertThat(histo.getBuckets().size(), equalTo(4));
-    }
-
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardSizeTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardSizeTermsIT.java
index 8f3d94c2eacdb..145830f02ee56 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardSizeTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/ShardSizeTermsIT.java
@@ -32,9 +32,10 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
-import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.bucket.terms.Terms;
 
 import java.util.HashMap;
 import java.util.List;
@@ -45,6 +46,11 @@
 import static org.hamcrest.Matchers.equalTo;
 
 public class ShardSizeTermsIT extends ShardSizeTestCase {
+
+    public ShardSizeTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     public void testNoShardSizeString() throws Exception {
         createIdx("type=keyword");
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
index 9c334df1d806b..e914b87754865 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
@@ -31,17 +31,21 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.index.query.TermQueryBuilder;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.script.MockScriptPlugin;
@@ -61,6 +65,7 @@
 import org.opensearch.search.aggregations.bucket.terms.heuristic.ScriptHeuristic;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.search.aggregations.bucket.SharedSignificantTermsTestMethods;
 
 import java.io.IOException;
@@ -77,6 +82,7 @@
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.significantTerms;
 import static org.opensearch.search.aggregations.AggregationBuilders.significantText;
@@ -89,12 +95,29 @@
 import static org.hamcrest.Matchers.is;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class SignificantTermsSignificanceScoreIT extends OpenSearchIntegTestCase {
+public class SignificantTermsSignificanceScoreIT extends ParameterizedOpenSearchIntegTestCase {
 
     static final String INDEX_NAME = "testidx";
     static final String TEXT_FIELD = "text";
     static final String CLASS_FIELD = "class";
 
+    public SignificantTermsSignificanceScoreIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(TestScriptPlugin.class);
@@ -206,14 +229,42 @@ public void testXContentResponse() throws Exception {
             + "\"score\":0.75,"
             + "\"bg_count\":4"
             + "}]}}]}}";
-        assertThat(Strings.toString(responseBuilder), equalTo(result));
+        assertThat(responseBuilder.toString(), equalTo(result));
+
+    }
+
+    public void testConsistencyWithDifferentShardCounts() throws Exception {
+        // The purpose of this test is to validate that the aggregation results do not change with shard count.
+        // bg_count for significant term agg is summed up across shards, so in this test we compare a 1 shard and 2 shard search request
+        String type = randomBoolean() ? "text" : "long";
+        String settings = "{\"index.number_of_shards\": 1, \"index.number_of_replicas\": 0}";
+        SharedSignificantTermsTestMethods.index01Docs(type, settings, this);
 
+        SearchRequestBuilder request = client().prepareSearch(INDEX_NAME)
+            .setQuery(new TermQueryBuilder(CLASS_FIELD, "0"))
+            .addAggregation((significantTerms("sig_terms").field(TEXT_FIELD)));
+
+        SearchResponse response1 = request.get();
+
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest("*")).get());
+
+        settings = "{\"index.number_of_shards\": 2, \"index.number_of_replicas\": 0}";
+        // We use a custom routing strategy here to ensure that each shard will have at least 1 bucket.
+        // If there are no buckets collected for a shard, then that will affect the scoring and bg_count and our assertion will not be
+        // valid.
+        SharedSignificantTermsTestMethods.index01DocsWithRouting(type, settings, this);
+        SearchResponse response2 = request.get();
+
+        assertEquals(
+            response1.getAggregations().asMap().get("sig_terms").toString(),
+            response2.getAggregations().asMap().get("sig_terms").toString()
+        );
     }
 
     public void testPopularTermManyDeletedDocs() throws Exception {
         String settings = "{\"index.number_of_shards\": 1, \"index.number_of_replicas\": 0}";
         assertAcked(
-            prepareCreate(INDEX_NAME).setSettings(settings, XContentType.JSON)
+            prepareCreate(INDEX_NAME).setSettings(settings, MediaTypeRegistry.JSON)
                 .setMapping("text", "type=keyword", CLASS_FIELD, "type=keyword")
         );
         String[] cat1v1 = { "constant", "one" };
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsDocCountErrorIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsDocCountErrorIT.java
index 3d76b994ebac3..3fcf4b5d533d4 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsDocCountErrorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsDocCountErrorIT.java
@@ -32,23 +32,30 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregatorFactory.ExecutionMode;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -60,7 +67,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class TermsDocCountErrorIT extends OpenSearchIntegTestCase {
+public class TermsDocCountErrorIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String STRING_FIELD_NAME = "s_value";
     private static final String LONG_FIELD_NAME = "l_value";
@@ -72,6 +79,23 @@ public static String randomExecutionHint() {
 
     private static int numRoutingValues;
 
+    public TermsDocCountErrorIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping(STRING_FIELD_NAME, "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsShardMinDocCountIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
index 852c3760751b3..b0d8e7ea02e8f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
@@ -31,23 +31,29 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilter;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTermsAggregatorFactory;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.significantTerms;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -55,9 +61,27 @@
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.equalTo;
 
-public class TermsShardMinDocCountIT extends OpenSearchIntegTestCase {
+public class TermsShardMinDocCountIT extends ParameterizedOpenSearchIntegTestCase {
+
     private static final String index = "someindex";
 
+    public TermsShardMinDocCountIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private static String randomExecutionHint() {
         return randomBoolean() ? null : randomFrom(SignificantTermsAggregatorFactory.ExecutionMode.values()).toString();
     }
@@ -124,10 +148,10 @@ private void addTermsDocs(String term, int numInClass, int numNotInClass, List<I
         String sourceClass = "{\"text\": \"" + term + "\", \"class\":" + "true" + "}";
         String sourceNotClass = "{\"text\": \"" + term + "\", \"class\":" + "false" + "}";
         for (int i = 0; i < numInClass; i++) {
-            builders.add(client().prepareIndex(index).setSource(sourceClass, XContentType.JSON));
+            builders.add(client().prepareIndex(index).setSource(sourceClass, MediaTypeRegistry.JSON));
         }
         for (int i = 0; i < numNotInClass; i++) {
-            builders.add(client().prepareIndex(index).setSource(sourceNotClass, XContentType.JSON));
+            builders.add(client().prepareIndex(index).setSource(sourceNotClass, MediaTypeRegistry.JSON));
         }
     }
 
@@ -188,7 +212,7 @@ public void testShardMinDocCountTermsTest() throws Exception {
     private static void addTermsDocs(String term, int numDocs, List<IndexRequestBuilder> builders) {
         String sourceClass = "{\"text\": \"" + term + "\"}";
         for (int i = 0; i < numDocs; i++) {
-            builders.add(client().prepareIndex(index).setSource(sourceClass, XContentType.JSON));
+            builders.add(client().prepareIndex(index).setSource(sourceClass, MediaTypeRegistry.JSON));
         }
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/BaseStringTermsTestCase.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/BaseStringTermsTestCase.java
new file mode 100644
index 0000000000000..20caa4fd076fe
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/BaseStringTermsTestCase.java
@@ -0,0 +1,261 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.index.fielddata.ScriptDocValues;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
+import org.opensearch.search.aggregations.bucket.AbstractTermsTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.SuiteScopeTestCase
+public class BaseStringTermsTestCase extends AbstractTermsTestCase {
+
+    protected static final String SINGLE_VALUED_FIELD_NAME = "s_value";
+    protected static final String MULTI_VALUED_FIELD_NAME = "s_values";
+    protected static Map<String, Map<String, Object>> expectedMultiSortBuckets;
+
+    public BaseStringTermsTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Collections.singleton(CustomScriptPlugin.class);
+    }
+
+    @Before
+    public void randomizeOptimizations() {
+        TermsAggregatorFactory.COLLECT_SEGMENT_ORDS = randomBoolean();
+        TermsAggregatorFactory.REMAP_GLOBAL_ORDS = randomBoolean();
+    }
+
+    @After
+    public void resetOptimizations() {
+        TermsAggregatorFactory.COLLECT_SEGMENT_ORDS = null;
+        TermsAggregatorFactory.REMAP_GLOBAL_ORDS = null;
+    }
+
+    public static class CustomScriptPlugin extends AggregationTestScriptsPlugin {
+
+        @Override
+        protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
+            Map<String, Function<Map<String, Object>, Object>> scripts = super.pluginScripts();
+
+            scripts.put("'foo_' + _value", vars -> "foo_" + (String) vars.get("_value"));
+            scripts.put("_value.substring(0,3)", vars -> ((String) vars.get("_value")).substring(0, 3));
+
+            scripts.put("doc['" + MULTI_VALUED_FIELD_NAME + "']", vars -> {
+                Map<?, ?> doc = (Map) vars.get("doc");
+                return doc.get(MULTI_VALUED_FIELD_NAME);
+            });
+
+            scripts.put("doc['" + SINGLE_VALUED_FIELD_NAME + "'].value", vars -> {
+                Map<?, ?> doc = (Map) vars.get("doc");
+                ScriptDocValues.Strings value = (ScriptDocValues.Strings) doc.get(SINGLE_VALUED_FIELD_NAME);
+                return value.getValue();
+            });
+
+            scripts.put("42", vars -> 42);
+
+            return scripts;
+        }
+
+        @Override
+        protected Map<String, Function<Map<String, Object>, Object>> nonDeterministicPluginScripts() {
+            Map<String, Function<Map<String, Object>, Object>> scripts = new HashMap<>();
+
+            scripts.put("Math.random()", vars -> randomDouble());
+
+            return scripts;
+        }
+    }
+
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareCreate("idx")
+                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
+                .get()
+        );
+        List<IndexRequestBuilder> builders = new ArrayList<>();
+        for (int i = 0; i < 5; i++) {
+            builders.add(
+                client().prepareIndex("idx")
+                    .setSource(
+                        jsonBuilder().startObject()
+                            .field(SINGLE_VALUED_FIELD_NAME, "val" + i)
+                            .field("i", i)
+                            .field("constant", 1)
+                            .field("tag", i < 5 / 2 + 1 ? "more" : "less")
+                            .startArray(MULTI_VALUED_FIELD_NAME)
+                            .value("val" + i)
+                            .value("val" + (i + 1))
+                            .endArray()
+                            .endObject()
+                    )
+            );
+        }
+
+        getMultiSortDocs(builders);
+
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareCreate("high_card_idx")
+                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
+                .get()
+        );
+        for (int i = 0; i < 100; i++) {
+            builders.add(
+                client().prepareIndex("high_card_idx")
+                    .setSource(
+                        jsonBuilder().startObject()
+                            .field(SINGLE_VALUED_FIELD_NAME, "val" + Strings.padStart(i + "", 3, '0'))
+                            .startArray(MULTI_VALUED_FIELD_NAME)
+                            .value("val" + Strings.padStart(i + "", 3, '0'))
+                            .value("val" + Strings.padStart((i + 1) + "", 3, '0'))
+                            .endArray()
+                            .endObject()
+                    )
+            );
+        }
+        prepareCreate("empty_bucket_idx").setMapping(SINGLE_VALUED_FIELD_NAME, "type=integer").get();
+
+        for (int i = 0; i < 2; i++) {
+            builders.add(
+                client().prepareIndex("empty_bucket_idx")
+                    .setId("" + i)
+                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, i * 2).endObject())
+            );
+        }
+        indexRandom(true, builders);
+        createIndex("idx_unmapped");
+        ensureSearchable();
+    }
+
+    private void getMultiSortDocs(List<IndexRequestBuilder> builders) throws IOException {
+        expectedMultiSortBuckets = new HashMap<>();
+        Map<String, Object> bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val1");
+        bucketProps.put("_count", 3L);
+        bucketProps.put("avg_l", 1d);
+        bucketProps.put("sum_d", 6d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val2");
+        bucketProps.put("_count", 3L);
+        bucketProps.put("avg_l", 2d);
+        bucketProps.put("sum_d", 6d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val3");
+        bucketProps.put("_count", 2L);
+        bucketProps.put("avg_l", 3d);
+        bucketProps.put("sum_d", 3d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val4");
+        bucketProps.put("_count", 2L);
+        bucketProps.put("avg_l", 3d);
+        bucketProps.put("sum_d", 4d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val5");
+        bucketProps.put("_count", 2L);
+        bucketProps.put("avg_l", 5d);
+        bucketProps.put("sum_d", 3d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val6");
+        bucketProps.put("_count", 1L);
+        bucketProps.put("avg_l", 5d);
+        bucketProps.put("sum_d", 1d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+        bucketProps = new HashMap<>();
+        bucketProps.put("_term", "val7");
+        bucketProps.put("_count", 1L);
+        bucketProps.put("avg_l", 5d);
+        bucketProps.put("sum_d", 1d);
+        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
+
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareCreate("sort_idx")
+                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
+                .get()
+        );
+        for (int i = 1; i <= 3; i++) {
+            builders.add(
+                client().prepareIndex("sort_idx")
+                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val1").field("l", 1).field("d", i).endObject())
+            );
+            builders.add(
+                client().prepareIndex("sort_idx")
+                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val2").field("l", 2).field("d", i).endObject())
+            );
+        }
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val3").field("l", 3).field("d", 1).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val3").field("l", 3).field("d", 2).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val4").field("l", 3).field("d", 1).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val4").field("l", 3).field("d", 3).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val5").field("l", 5).field("d", 1).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val5").field("l", 5).field("d", 2).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val6").field("l", 5).field("d", 1).endObject())
+        );
+        builders.add(
+            client().prepareIndex("sort_idx")
+                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val7").field("l", 5).field("d", 1).endObject())
+        );
+    }
+
+    protected String key(Terms.Bucket bucket) {
+        return bucket.getKeyAsString();
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/StringTermsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/StringTermsIT.java
index 3190bcb72fcbb..8c727d280ec52 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/StringTermsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/terms/StringTermsIT.java
@@ -32,25 +32,19 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.fielddata.ScriptDocValues;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IndexFieldMapper;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationExecutionException;
-import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.BucketOrder;
-import org.opensearch.search.aggregations.bucket.AbstractTermsTestCase;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
 import org.opensearch.search.aggregations.metrics.Avg;
@@ -60,23 +54,13 @@
 import org.opensearch.search.aggregations.support.ValueType;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
-import org.junit.After;
-import org.junit.Before;
 
-import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
 import java.util.Set;
-import java.util.function.Function;
 
-import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.extendedStats;
@@ -93,227 +77,10 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class StringTermsIT extends AbstractTermsTestCase {
+public class StringTermsIT extends BaseStringTermsTestCase {
 
-    private static final String SINGLE_VALUED_FIELD_NAME = "s_value";
-    private static final String MULTI_VALUED_FIELD_NAME = "s_values";
-    private static Map<String, Map<String, Object>> expectedMultiSortBuckets;
-
-    @Override
-    protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Collections.singleton(CustomScriptPlugin.class);
-    }
-
-    @Before
-    public void randomizeOptimizations() {
-        TermsAggregatorFactory.COLLECT_SEGMENT_ORDS = randomBoolean();
-        TermsAggregatorFactory.REMAP_GLOBAL_ORDS = randomBoolean();
-    }
-
-    @After
-    public void resetOptimizations() {
-        TermsAggregatorFactory.COLLECT_SEGMENT_ORDS = null;
-        TermsAggregatorFactory.REMAP_GLOBAL_ORDS = null;
-    }
-
-    public static class CustomScriptPlugin extends AggregationTestScriptsPlugin {
-
-        @Override
-        protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
-            Map<String, Function<Map<String, Object>, Object>> scripts = super.pluginScripts();
-
-            scripts.put("'foo_' + _value", vars -> "foo_" + (String) vars.get("_value"));
-            scripts.put("_value.substring(0,3)", vars -> ((String) vars.get("_value")).substring(0, 3));
-
-            scripts.put("doc['" + MULTI_VALUED_FIELD_NAME + "']", vars -> {
-                Map<?, ?> doc = (Map) vars.get("doc");
-                return doc.get(MULTI_VALUED_FIELD_NAME);
-            });
-
-            scripts.put("doc['" + SINGLE_VALUED_FIELD_NAME + "'].value", vars -> {
-                Map<?, ?> doc = (Map) vars.get("doc");
-                ScriptDocValues.Strings value = (ScriptDocValues.Strings) doc.get(SINGLE_VALUED_FIELD_NAME);
-                return value.getValue();
-            });
-
-            scripts.put("42", vars -> 42);
-
-            return scripts;
-        }
-
-        @Override
-        protected Map<String, Function<Map<String, Object>, Object>> nonDeterministicPluginScripts() {
-            Map<String, Function<Map<String, Object>, Object>> scripts = new HashMap<>();
-
-            scripts.put("Math.random()", vars -> StringTermsIT.randomDouble());
-
-            return scripts;
-        }
-    }
-
-    @Override
-    public void setupSuiteScopeCluster() throws Exception {
-        assertAcked(
-            client().admin()
-                .indices()
-                .prepareCreate("idx")
-                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
-                .get()
-        );
-        List<IndexRequestBuilder> builders = new ArrayList<>();
-        for (int i = 0; i < 5; i++) {
-            builders.add(
-                client().prepareIndex("idx")
-                    .setSource(
-                        jsonBuilder().startObject()
-                            .field(SINGLE_VALUED_FIELD_NAME, "val" + i)
-                            .field("i", i)
-                            .field("constant", 1)
-                            .field("tag", i < 5 / 2 + 1 ? "more" : "less")
-                            .startArray(MULTI_VALUED_FIELD_NAME)
-                            .value("val" + i)
-                            .value("val" + (i + 1))
-                            .endArray()
-                            .endObject()
-                    )
-            );
-        }
-
-        getMultiSortDocs(builders);
-
-        assertAcked(
-            client().admin()
-                .indices()
-                .prepareCreate("high_card_idx")
-                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
-                .get()
-        );
-        for (int i = 0; i < 100; i++) {
-            builders.add(
-                client().prepareIndex("high_card_idx")
-                    .setSource(
-                        jsonBuilder().startObject()
-                            .field(SINGLE_VALUED_FIELD_NAME, "val" + Strings.padStart(i + "", 3, '0'))
-                            .startArray(MULTI_VALUED_FIELD_NAME)
-                            .value("val" + Strings.padStart(i + "", 3, '0'))
-                            .value("val" + Strings.padStart((i + 1) + "", 3, '0'))
-                            .endArray()
-                            .endObject()
-                    )
-            );
-        }
-        prepareCreate("empty_bucket_idx").setMapping(SINGLE_VALUED_FIELD_NAME, "type=integer").get();
-
-        for (int i = 0; i < 2; i++) {
-            builders.add(
-                client().prepareIndex("empty_bucket_idx")
-                    .setId("" + i)
-                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, i * 2).endObject())
-            );
-        }
-        indexRandom(true, builders);
-        createIndex("idx_unmapped");
-        ensureSearchable();
-    }
-
-    private void getMultiSortDocs(List<IndexRequestBuilder> builders) throws IOException {
-        expectedMultiSortBuckets = new HashMap<>();
-        Map<String, Object> bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val1");
-        bucketProps.put("_count", 3L);
-        bucketProps.put("avg_l", 1d);
-        bucketProps.put("sum_d", 6d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val2");
-        bucketProps.put("_count", 3L);
-        bucketProps.put("avg_l", 2d);
-        bucketProps.put("sum_d", 6d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val3");
-        bucketProps.put("_count", 2L);
-        bucketProps.put("avg_l", 3d);
-        bucketProps.put("sum_d", 3d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val4");
-        bucketProps.put("_count", 2L);
-        bucketProps.put("avg_l", 3d);
-        bucketProps.put("sum_d", 4d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val5");
-        bucketProps.put("_count", 2L);
-        bucketProps.put("avg_l", 5d);
-        bucketProps.put("sum_d", 3d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val6");
-        bucketProps.put("_count", 1L);
-        bucketProps.put("avg_l", 5d);
-        bucketProps.put("sum_d", 1d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-        bucketProps = new HashMap<>();
-        bucketProps.put("_term", "val7");
-        bucketProps.put("_count", 1L);
-        bucketProps.put("avg_l", 5d);
-        bucketProps.put("sum_d", 1d);
-        expectedMultiSortBuckets.put((String) bucketProps.get("_term"), bucketProps);
-
-        assertAcked(
-            client().admin()
-                .indices()
-                .prepareCreate("sort_idx")
-                .setMapping(SINGLE_VALUED_FIELD_NAME, "type=keyword", MULTI_VALUED_FIELD_NAME, "type=keyword", "tag", "type=keyword")
-                .get()
-        );
-        for (int i = 1; i <= 3; i++) {
-            builders.add(
-                client().prepareIndex("sort_idx")
-                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val1").field("l", 1).field("d", i).endObject())
-            );
-            builders.add(
-                client().prepareIndex("sort_idx")
-                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val2").field("l", 2).field("d", i).endObject())
-            );
-        }
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val3").field("l", 3).field("d", 1).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val3").field("l", 3).field("d", 2).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val4").field("l", 3).field("d", 1).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val4").field("l", 3).field("d", 3).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val5").field("l", 5).field("d", 1).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val5").field("l", 5).field("d", 2).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val6").field("l", 5).field("d", 1).endObject())
-        );
-        builders.add(
-            client().prepareIndex("sort_idx")
-                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, "val7").field("l", 5).field("d", 1).endObject())
-        );
-    }
-
-    private String key(Terms.Bucket bucket) {
-        return bucket.getKeyAsString();
+    public StringTermsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
     }
 
     // the main purpose of this test is to make sure we're not allocating 2GB of memory per shard
@@ -1364,6 +1131,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testScriptWithValueType() throws Exception {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityIT.java
index 147f451c14de8..9ebec21367164 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityIT.java
@@ -32,9 +32,12 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
@@ -45,7 +48,9 @@
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -55,6 +60,7 @@
 import static java.util.Collections.emptyMap;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.cardinality;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -65,7 +71,24 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class CardinalityIT extends OpenSearchIntegTestCase {
+public class CardinalityIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public CardinalityIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -615,5 +638,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityWithRequestBreakerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityWithRequestBreakerIT.java
index e8d425596beb0..2bf5230c67b43 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityWithRequestBreakerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/CardinalityWithRequestBreakerIT.java
@@ -32,22 +32,46 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.OpenSearchException;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.BucketOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Map;
 import java.util.stream.IntStream;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.cardinality;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 
-public class CardinalityWithRequestBreakerIT extends OpenSearchIntegTestCase {
+public class CardinalityWithRequestBreakerIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public CardinalityWithRequestBreakerIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     /**
      * Test that searches using cardinality aggregations returns all request breaker memory.
@@ -62,7 +86,7 @@ public void testRequestBreaker() throws Exception {
                 .mapToObj(
                     i -> client().prepareIndex("test")
                         .setId("id_" + i)
-                        .setSource(org.opensearch.common.collect.Map.of("field0", randomAlphaOfLength(5), "field1", randomAlphaOfLength(5)))
+                        .setSource(Map.of("field0", randomAlphaOfLength(5), "field1", randomAlphaOfLength(5)))
                 )
                 .toArray(IndexRequestBuilder[]::new)
         );
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ExtendedStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ExtendedStatsIT.java
index cd0a649659c6e..3d804b9aa626e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ExtendedStatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ExtendedStatsIT.java
@@ -37,6 +37,7 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.global.Global;
@@ -44,7 +45,6 @@
 import org.opensearch.search.aggregations.bucket.missing.Missing;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.ExtendedStats.Bounds;
-import org.opensearch.search.aggregations.BucketOrder;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -70,6 +70,10 @@
 
 public class ExtendedStatsIT extends AbstractNumericTestCase {
 
+    public ExtendedStatsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -995,6 +999,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoBoundsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoBoundsIT.java
deleted file mode 100644
index 3af3b9e5212f8..0000000000000
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoBoundsIT.java
+++ /dev/null
@@ -1,277 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.metrics;
-
-import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.util.BigArray;
-import org.opensearch.search.aggregations.InternalAggregation;
-import org.opensearch.search.aggregations.bucket.global.Global;
-import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
-import org.opensearch.test.OpenSearchIntegTestCase;
-
-import java.util.List;
-
-import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
-import static org.opensearch.search.aggregations.AggregationBuilders.geoBounds;
-import static org.opensearch.search.aggregations.AggregationBuilders.global;
-import static org.opensearch.search.aggregations.AggregationBuilders.terms;
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
-import static org.hamcrest.Matchers.allOf;
-import static org.hamcrest.Matchers.closeTo;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.sameInstance;
-
-@OpenSearchIntegTestCase.SuiteScopeTestCase
-public class GeoBoundsIT extends AbstractGeoTestCase {
-    private static final String aggName = "geoBounds";
-
-    public void testSingleValuedField() throws Exception {
-        SearchResponse response = client().prepareSearch(IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
-    }
-
-    public void testSingleValuedField_getProperty() throws Exception {
-        SearchResponse searchResponse = client().prepareSearch(IDX_NAME)
-            .setQuery(matchAllQuery())
-            .addAggregation(global("global").subAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false)))
-            .get();
-
-        assertSearchResponse(searchResponse);
-
-        Global global = searchResponse.getAggregations().get("global");
-        assertThat(global, notNullValue());
-        assertThat(global.getName(), equalTo("global"));
-        assertThat(global.getDocCount(), equalTo((long) numDocs));
-        assertThat(global.getAggregations(), notNullValue());
-        assertThat(global.getAggregations().asMap().size(), equalTo(1));
-
-        GeoBounds geobounds = global.getAggregations().get(aggName);
-        assertThat(geobounds, notNullValue());
-        assertThat(geobounds.getName(), equalTo(aggName));
-        assertThat((GeoBounds) ((InternalAggregation) global).getProperty(aggName), sameInstance(geobounds));
-        GeoPoint topLeft = geobounds.topLeft();
-        GeoPoint bottomRight = geobounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
-        assertThat((double) ((InternalAggregation) global).getProperty(aggName + ".top"), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat((double) ((InternalAggregation) global).getProperty(aggName + ".left"), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(
-            (double) ((InternalAggregation) global).getProperty(aggName + ".bottom"),
-            closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE)
-        );
-        assertThat(
-            (double) ((InternalAggregation) global).getProperty(aggName + ".right"),
-            closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE)
-        );
-    }
-
-    public void testMultiValuedField() throws Exception {
-        SearchResponse response = client().prepareSearch(IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(MULTI_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(multiTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(multiTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(multiBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(multiBottomRight.lon(), GEOHASH_TOLERANCE));
-    }
-
-    public void testUnmapped() throws Exception {
-        SearchResponse response = client().prepareSearch(UNMAPPED_IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft, equalTo(null));
-        assertThat(bottomRight, equalTo(null));
-    }
-
-    public void testPartiallyUnmapped() throws Exception {
-        SearchResponse response = client().prepareSearch(IDX_NAME, UNMAPPED_IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(singleTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(singleTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(singleBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(singleBottomRight.lon(), GEOHASH_TOLERANCE));
-    }
-
-    public void testEmptyAggregation() throws Exception {
-        SearchResponse searchResponse = client().prepareSearch(EMPTY_IDX_NAME)
-            .setQuery(matchAllQuery())
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(0L));
-        GeoBounds geoBounds = searchResponse.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft, equalTo(null));
-        assertThat(bottomRight, equalTo(null));
-    }
-
-    public void testSingleValuedFieldNearDateLine() throws Exception {
-        SearchResponse response = client().prepareSearch(DATELINE_IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoPoint geoValuesTopLeft = new GeoPoint(38, -179);
-        GeoPoint geoValuesBottomRight = new GeoPoint(-24, 178);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(geoValuesTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(geoValuesTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(geoValuesBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(geoValuesBottomRight.lon(), GEOHASH_TOLERANCE));
-    }
-
-    public void testSingleValuedFieldNearDateLineWrapLongitude() throws Exception {
-
-        GeoPoint geoValuesTopLeft = new GeoPoint(38, 170);
-        GeoPoint geoValuesBottomRight = new GeoPoint(-24, -175);
-        SearchResponse response = client().prepareSearch(DATELINE_IDX_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(true))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(geoValuesTopLeft.lat(), GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(geoValuesTopLeft.lon(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(geoValuesBottomRight.lat(), GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(geoValuesBottomRight.lon(), GEOHASH_TOLERANCE));
-    }
-
-    /**
-     * This test forces the {@link GeoBoundsAggregator} to resize the {@link BigArray}s it uses to ensure they are resized correctly
-     */
-    public void testSingleValuedFieldAsSubAggToHighCardTermsAgg() {
-        SearchResponse response = client().prepareSearch(HIGH_CARD_IDX_NAME)
-            .addAggregation(
-                terms("terms").field(NUMBER_FIELD_NAME)
-                    .subAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            )
-            .get();
-
-        assertSearchResponse(response);
-
-        Terms terms = response.getAggregations().get("terms");
-        assertThat(terms, notNullValue());
-        assertThat(terms.getName(), equalTo("terms"));
-        List<? extends Bucket> buckets = terms.getBuckets();
-        assertThat(buckets.size(), equalTo(10));
-        for (int i = 0; i < 10; i++) {
-            Bucket bucket = buckets.get(i);
-            assertThat(bucket, notNullValue());
-            assertThat("InternalBucket " + bucket.getKey() + " has wrong number of documents", bucket.getDocCount(), equalTo(1L));
-            GeoBounds geoBounds = bucket.getAggregations().get(aggName);
-            assertThat(geoBounds, notNullValue());
-            assertThat(geoBounds.getName(), equalTo(aggName));
-            assertThat(geoBounds.topLeft().getLat(), allOf(greaterThanOrEqualTo(-90.0), lessThanOrEqualTo(90.0)));
-            assertThat(geoBounds.topLeft().getLon(), allOf(greaterThanOrEqualTo(-180.0), lessThanOrEqualTo(180.0)));
-            assertThat(geoBounds.bottomRight().getLat(), allOf(greaterThanOrEqualTo(-90.0), lessThanOrEqualTo(90.0)));
-            assertThat(geoBounds.bottomRight().getLon(), allOf(greaterThanOrEqualTo(-180.0), lessThanOrEqualTo(180.0)));
-        }
-    }
-
-    public void testSingleValuedFieldWithZeroLon() throws Exception {
-        SearchResponse response = client().prepareSearch(IDX_ZERO_NAME)
-            .addAggregation(geoBounds(aggName).field(SINGLE_VALUED_FIELD_NAME).wrapLongitude(false))
-            .get();
-
-        assertSearchResponse(response);
-
-        GeoBounds geoBounds = response.getAggregations().get(aggName);
-        assertThat(geoBounds, notNullValue());
-        assertThat(geoBounds.getName(), equalTo(aggName));
-        GeoPoint topLeft = geoBounds.topLeft();
-        GeoPoint bottomRight = geoBounds.bottomRight();
-        assertThat(topLeft.lat(), closeTo(1.0, GEOHASH_TOLERANCE));
-        assertThat(topLeft.lon(), closeTo(0.0, GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lat(), closeTo(1.0, GEOHASH_TOLERANCE));
-        assertThat(bottomRight.lon(), closeTo(0.0, GEOHASH_TOLERANCE));
-    }
-}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoCentroidIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoCentroidIT.java
index 7cd8b3ed39051..78100d1778ecf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoCentroidIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/GeoCentroidIT.java
@@ -34,16 +34,13 @@
 
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.search.aggregations.InternalAggregation;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGrid;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
-import java.util.List;
-
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.search.aggregations.AggregationBuilders.geoCentroid;
-import static org.opensearch.search.aggregations.AggregationBuilders.geohashGrid;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.closeTo;
@@ -58,6 +55,10 @@
 public class GeoCentroidIT extends AbstractGeoTestCase {
     private static final String aggName = "geoCentroid";
 
+    public GeoCentroidIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     public void testEmptyAggregation() throws Exception {
         SearchResponse response = client().prepareSearch(EMPTY_IDX_NAME)
             .setQuery(matchAllQuery())
@@ -168,33 +169,4 @@ public void testMultiValuedField() throws Exception {
         assertThat(centroid.lon(), closeTo(multiCentroid.lon(), GEOHASH_TOLERANCE));
         assertEquals(2 * numDocs, geoCentroid.count());
     }
-
-    public void testSingleValueFieldAsSubAggToGeohashGrid() throws Exception {
-        SearchResponse response = client().prepareSearch(HIGH_CARD_IDX_NAME)
-            .addAggregation(
-                geohashGrid("geoGrid").field(SINGLE_VALUED_FIELD_NAME).subAggregation(geoCentroid(aggName).field(SINGLE_VALUED_FIELD_NAME))
-            )
-            .get();
-        assertSearchResponse(response);
-
-        GeoGrid grid = response.getAggregations().get("geoGrid");
-        assertThat(grid, notNullValue());
-        assertThat(grid.getName(), equalTo("geoGrid"));
-        List<? extends GeoGrid.Bucket> buckets = grid.getBuckets();
-        for (GeoGrid.Bucket cell : buckets) {
-            String geohash = cell.getKeyAsString();
-            GeoPoint expectedCentroid = expectedCentroidsForGeoHash.get(geohash);
-            GeoCentroid centroidAgg = cell.getAggregations().get(aggName);
-            assertThat(
-                "Geohash " + geohash + " has wrong centroid latitude ",
-                expectedCentroid.lat(),
-                closeTo(centroidAgg.centroid().lat(), GEOHASH_TOLERANCE)
-            );
-            assertThat(
-                "Geohash " + geohash + " has wrong centroid longitude",
-                expectedCentroid.lon(),
-                closeTo(centroidAgg.centroid().lon(), GEOHASH_TOLERANCE)
-            );
-        }
-    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksIT.java
index 20fc6aaee20c9..7ca5130388eea 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksIT.java
@@ -38,12 +38,12 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.search.aggregations.BucketOrder;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -53,7 +53,7 @@
 import java.util.Map;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.util.CollectionUtils.iterableAsArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.iterableAsArrayList;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
@@ -72,6 +72,10 @@
 
 public class HDRPercentileRanksIT extends AbstractNumericTestCase {
 
+    public HDRPercentileRanksIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -716,6 +720,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentilesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentilesIT.java
index 2660dbe0a88ed..ec913b3e130f5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentilesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/HDRPercentilesIT.java
@@ -34,7 +34,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -75,6 +75,10 @@
 
 public class HDRPercentilesIT extends AbstractNumericTestCase {
 
+    public HDRPercentilesIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -687,6 +691,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationIT.java
index 226b4dbca18d9..b8447d682abae 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationIT.java
@@ -68,8 +68,8 @@
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.range;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
-import static org.opensearch.search.aggregations.metrics.MedianAbsoluteDeviationAggregatorTests.IsCloseToRelative.closeToRelative;
 import static org.opensearch.search.aggregations.metrics.MedianAbsoluteDeviationAggregatorTests.ExactMedianAbsoluteDeviation.calculateMAD;
+import static org.opensearch.search.aggregations.metrics.MedianAbsoluteDeviationAggregatorTests.IsCloseToRelative.closeToRelative;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
@@ -91,6 +91,10 @@ public class MedianAbsoluteDeviationIT extends AbstractNumericTestCase {
     private static double singleValueExactMAD;
     private static double multiValueExactMAD;
 
+    public MedianAbsoluteDeviationIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         final Settings settings = Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0).build();
@@ -643,5 +647,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ScriptedMetricIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ScriptedMetricIT.java
index 27dbc56cf3b79..ced2358ac3f78 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ScriptedMetricIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ScriptedMetricIT.java
@@ -32,14 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
@@ -53,12 +56,14 @@
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -69,6 +74,7 @@
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.scriptedMetric;
@@ -87,10 +93,27 @@
 
 @ClusterScope(scope = Scope.SUITE)
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class ScriptedMetricIT extends OpenSearchIntegTestCase {
+public class ScriptedMetricIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static long numDocs;
 
+    public ScriptedMetricIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -332,7 +355,7 @@ public void setupSuiteScopeCluster() throws Exception {
                     new BytesArray(
                         "{\"script\": {\"lang\": \"" + MockScriptPlugin.NAME + "\"," + " \"source\": \"vars.multiplier = 3\"} }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
@@ -345,7 +368,7 @@ public void setupSuiteScopeCluster() throws Exception {
                     new BytesArray(
                         "{\"script\": {\"lang\": \"" + MockScriptPlugin.NAME + "\"," + " \"source\": \"state.list.add(vars.multiplier)\"} }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
@@ -361,7 +384,7 @@ public void setupSuiteScopeCluster() throws Exception {
                             + "\","
                             + " \"source\": \"sum state values as a new aggregation\"} }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
@@ -377,7 +400,7 @@ public void setupSuiteScopeCluster() throws Exception {
                             + "\","
                             + " \"source\": \"sum all states (lists) values as a new aggregation\"} }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
@@ -435,7 +458,9 @@ public void testMap() {
         assertThat(scriptedMetricAggregation.aggregation(), notNullValue());
         assertThat(scriptedMetricAggregation.aggregation(), instanceOf(ArrayList.class));
         List<?> aggregationList = (List<?>) scriptedMetricAggregation.aggregation();
-        assertThat(aggregationList.size(), equalTo(getNumShards("idx").numPrimaries));
+        // with script based aggregation, if it does not support reduce then aggregationList size
+        // will be numShards * slicesCount
+        assertThat(aggregationList.size(), greaterThanOrEqualTo(getNumShards("idx").numPrimaries));
         int numShardsRun = 0;
         for (Object object : aggregationList) {
             assertThat(object, notNullValue());
@@ -483,7 +508,9 @@ public void testMapWithParams() {
         assertThat(scriptedMetricAggregation.aggregation(), notNullValue());
         assertThat(scriptedMetricAggregation.aggregation(), instanceOf(ArrayList.class));
         List<?> aggregationList = (List<?>) scriptedMetricAggregation.aggregation();
-        assertThat(aggregationList.size(), equalTo(getNumShards("idx").numPrimaries));
+        // with script based aggregation, if it does not support reduce then aggregationList size
+        // will be numShards * slicesCount
+        assertThat(aggregationList.size(), greaterThanOrEqualTo(getNumShards("idx").numPrimaries));
         int numShardsRun = 0;
         for (Object object : aggregationList) {
             assertThat(object, notNullValue());
@@ -535,7 +562,9 @@ public void testInitMutatesParams() {
         assertThat(scriptedMetricAggregation.aggregation(), notNullValue());
         assertThat(scriptedMetricAggregation.aggregation(), instanceOf(ArrayList.class));
         List<?> aggregationList = (List<?>) scriptedMetricAggregation.aggregation();
-        assertThat(aggregationList.size(), equalTo(getNumShards("idx").numPrimaries));
+        // with script based aggregation, if it does not support reduce then aggregationList size
+        // will be numShards * slicesCount
+        assertThat(aggregationList.size(), greaterThanOrEqualTo(getNumShards("idx").numPrimaries));
         long totalCount = 0;
         for (Object object : aggregationList) {
             assertThat(object, notNullValue());
@@ -588,7 +617,9 @@ public void testMapCombineWithParams() {
         assertThat(scriptedMetricAggregation.aggregation(), notNullValue());
         assertThat(scriptedMetricAggregation.aggregation(), instanceOf(ArrayList.class));
         List<?> aggregationList = (List<?>) scriptedMetricAggregation.aggregation();
-        assertThat(aggregationList.size(), equalTo(getNumShards("idx").numPrimaries));
+        // with script based aggregation, if it does not support reduce then aggregationList size
+        // will be numShards * slicesCount
+        assertThat(aggregationList.size(), greaterThanOrEqualTo(getNumShards("idx").numPrimaries));
         long totalCount = 0;
         for (Object object : aggregationList) {
             assertThat(object, notNullValue());
@@ -651,7 +682,9 @@ public void testInitMapCombineWithParams() {
         assertThat(scriptedMetricAggregation.aggregation(), notNullValue());
         assertThat(scriptedMetricAggregation.aggregation(), instanceOf(ArrayList.class));
         List<?> aggregationList = (List<?>) scriptedMetricAggregation.aggregation();
-        assertThat(aggregationList.size(), equalTo(getNumShards("idx").numPrimaries));
+        // with script based aggregation, if it does not support reduce then aggregationList size
+        // will be numShards * slicesCount
+        assertThat(aggregationList.size(), greaterThanOrEqualTo(getNumShards("idx").numPrimaries));
         long totalCount = 0;
         for (Object object : aggregationList) {
             assertThat(object, notNullValue());
@@ -1368,6 +1401,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testConflictingAggAndScriptParams() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/StatsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/StatsIT.java
index debdde8e13fe7..f957a74eeb9d0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/StatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/StatsIT.java
@@ -39,12 +39,12 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.search.aggregations.BucketOrder;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -66,6 +66,10 @@
 import static org.hamcrest.Matchers.sameInstance;
 
 public class StatsIT extends AbstractNumericTestCase {
+    public StatsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -384,5 +388,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/SumIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/SumIT.java
index fe236f04c19e8..382d656448114 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/SumIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/SumIT.java
@@ -68,6 +68,10 @@
 
 public class SumIT extends AbstractNumericTestCase {
 
+    public SumIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(MetricAggScriptPlugin.class);
@@ -359,6 +363,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testFieldAlias() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
index adf027222d7d9..941d3a888db29 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksIT.java
@@ -34,17 +34,17 @@
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.filter.Filter;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.search.aggregations.BucketOrder;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -72,6 +72,10 @@
 
 public class TDigestPercentileRanksIT extends AbstractNumericTestCase {
 
+    public TDigestPercentileRanksIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -626,6 +630,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesIT.java
index fda15f9b90ea2..6457cf9307fa1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesIT.java
@@ -34,7 +34,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -74,6 +74,10 @@
 
 public class TDigestPercentilesIT extends AbstractNumericTestCase {
 
+    public TDigestPercentilesIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(AggregationTestScriptsPlugin.class);
@@ -597,5 +601,6 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TopHitsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TopHitsIT.java
index c3240c5eef7c5..10e51079cf389 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TopHitsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/TopHitsIT.java
@@ -31,6 +31,8 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.util.ArrayUtil;
@@ -40,7 +42,8 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -67,8 +70,10 @@
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
@@ -83,6 +88,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.nestedQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
@@ -105,11 +111,28 @@
 import static org.hamcrest.Matchers.sameInstance;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase()
-public class TopHitsIT extends OpenSearchIntegTestCase {
+public class TopHitsIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String TERMS_AGGS_FIELD = "terms";
     private static final String SORT_FIELD = "sort";
 
+    public TopHitsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -1386,7 +1409,7 @@ public void testWithRescore() {
             SearchResponse response = client().prepareSearch("idx")
                 .addRescorer(new QueryRescorerBuilder(new MatchAllQueryBuilder().boost(3.0f)))
                 .addAggregation(
-                    terms("terms").field(TERMS_AGGS_FIELD).subAggregation(topHits("hits").sort(SortBuilders.fieldSort("_type")))
+                    terms("terms").field(TERMS_AGGS_FIELD).subAggregation(topHits("hits").sort(SortBuilders.fieldSort("_index")))
                 )
                 .get();
             Terms terms = response.getAggregations().get("terms");
@@ -1403,7 +1426,7 @@ public void testWithRescore() {
                 .addRescorer(new QueryRescorerBuilder(new MatchAllQueryBuilder().boost(3.0f)))
                 .addAggregation(
                     terms("terms").field(TERMS_AGGS_FIELD)
-                        .subAggregation(topHits("hits").sort(SortBuilders.scoreSort()).sort(SortBuilders.fieldSort("_type")))
+                        .subAggregation(topHits("hits").sort(SortBuilders.scoreSort()).sort(SortBuilders.fieldSort("_index")))
                 )
                 .get();
             Terms terms = response.getAggregations().get("terms");
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ValueCountIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ValueCountIT.java
index 82e667bccc576..833d1ce3bb4c3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ValueCountIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/metrics/ValueCountIT.java
@@ -31,8 +31,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -42,7 +45,9 @@
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -51,6 +56,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.count;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.global;
@@ -67,7 +73,25 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class ValueCountIT extends OpenSearchIntegTestCase {
+public class ValueCountIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ValueCountIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
@@ -363,6 +387,7 @@ public void testScriptCaching() throws Exception {
                 .getMissCount(),
             equalTo(2L)
         );
+        internalCluster().wipeIndices("cache_test_idx");
     }
 
     public void testOrderByEmptyAggregation() throws Exception {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/AvgBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/AvgBucketIT.java
index 6cd16a47e98d2..bec9203384026 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/AvgBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/AvgBucketIT.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
@@ -42,11 +46,15 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -58,7 +66,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class AvgBucketIT extends OpenSearchIntegTestCase {
+public class AvgBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -69,6 +77,23 @@ public class AvgBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public AvgBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketScriptIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketScriptIT.java
index 5de4e5162247d..4c3129eb89e3b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketScriptIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketScriptIT.java
@@ -32,12 +32,16 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
@@ -47,9 +51,11 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -58,6 +64,7 @@
 import java.util.function.Function;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateRange;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
@@ -69,7 +76,7 @@
 import static org.hamcrest.Matchers.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class BucketScriptIT extends OpenSearchIntegTestCase {
+public class BucketScriptIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String FIELD_1_NAME = "field1";
     private static final String FIELD_2_NAME = "field2";
@@ -83,6 +90,23 @@ public class BucketScriptIT extends OpenSearchIntegTestCase {
     private static int maxNumber;
     private static long date;
 
+    public BucketScriptIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -551,7 +575,7 @@ public void testStoredScript() {
                 // Script source is not interpreted but it references a pre-defined script from CustomScriptPlugin
                 .setContent(
                     new BytesArray("{ \"script\": {\"lang\": \"" + CustomScriptPlugin.NAME + "\"," + " \"source\": \"my_script\" } }"),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSelectorIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSelectorIT.java
index 7674679378758..a7b28add7373a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSelectorIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSelectorIT.java
@@ -32,11 +32,15 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
@@ -46,9 +50,11 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -57,6 +63,7 @@
 import java.util.function.Function;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.bucketSelector;
@@ -70,7 +77,7 @@
 import static org.hamcrest.Matchers.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class BucketSelectorIT extends OpenSearchIntegTestCase {
+public class BucketSelectorIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String FIELD_1_NAME = "field1";
     private static final String FIELD_2_NAME = "field2";
@@ -82,6 +89,23 @@ public class BucketSelectorIT extends OpenSearchIntegTestCase {
     private static int minNumber;
     private static int maxNumber;
 
+    public BucketSelectorIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
@@ -488,7 +512,7 @@ public void testStoredScript() {
                             + "\", "
                             + "\"source\": \"Double.isNaN(_value0) ? false : (_value0 + _value1 > 100)\" } }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
         );
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSortIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSortIT.java
index d05740a5a0f36..2e4fd7a412118 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSortIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/BucketSortIT.java
@@ -32,11 +32,15 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
@@ -44,15 +48,18 @@
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
@@ -68,7 +75,7 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class BucketSortIT extends OpenSearchIntegTestCase {
+public class BucketSortIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String INDEX = "bucket-sort-it-data-index";
     private static final String INDEX_WITH_GAPS = "bucket-sort-it-data-index-with-gaps";
@@ -78,6 +85,23 @@ public class BucketSortIT extends OpenSearchIntegTestCase {
     private static final String VALUE_1_FIELD = "value_1";
     private static final String VALUE_2_FIELD = "value_2";
 
+    public BucketSortIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex(INDEX, INDEX_WITH_GAPS);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DateDerivativeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DateDerivativeIT.java
index 2c7890fb7b1cb..b05ff7b4329cd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DateDerivativeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DateDerivativeIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateFormatters;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
@@ -44,6 +48,7 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.support.AggregationPath;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
 import org.junit.After;
 
@@ -55,9 +60,11 @@
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.dateHistogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.derivative;
@@ -69,13 +76,30 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class DateDerivativeIT extends OpenSearchIntegTestCase {
+public class DateDerivativeIT extends ParameterizedOpenSearchIntegTestCase {
 
     // some index names used during these tests
     private static final String IDX_DST_START = "idx_dst_start";
     private static final String IDX_DST_END = "idx_dst_end";
     private static final String IDX_DST_KATHMANDU = "idx_dst_kathmandu";
 
+    public DateDerivativeIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private ZonedDateTime date(int month, int day) {
         return ZonedDateTime.of(2012, month, day, 0, 0, 0, 0, ZoneOffset.UTC);
     }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DerivativeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DerivativeIT.java
index c03ed8277a3b4..18484c8a60ed7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DerivativeIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/DerivativeIT.java
@@ -32,11 +32,15 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
@@ -47,19 +51,23 @@
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.search.aggregations.support.AggregationPath;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.filters;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.stats;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
-import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.derivative;
 import static org.opensearch.search.aggregations.PipelineAggregatorBuilders.movingAvg;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -70,7 +78,7 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class DerivativeIT extends OpenSearchIntegTestCase {
+public class DerivativeIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -92,6 +100,23 @@ public class DerivativeIT extends OpenSearchIntegTestCase {
     private static Double[] firstDerivValueCounts_empty_rnd;
     private static long numDocsEmptyIdx_rnd;
 
+    public DerivativeIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
@@ -680,6 +705,7 @@ public void testAvgMovavgDerivNPE() throws Exception {
             .get();
 
         assertSearchResponse(response);
+        internalCluster().wipeIndices("movavg_npe");
     }
 
     private void checkBucketKeyAndDocCount(
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
index 85fe794b05fc6..299827e2413d4 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
@@ -45,11 +49,15 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -61,7 +69,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class ExtendedStatsBucketIT extends OpenSearchIntegTestCase {
+public class ExtendedStatsBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -72,6 +80,23 @@ public class ExtendedStatsBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public ExtendedStatsBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MaxBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MaxBucketIT.java
index 22890620d6b15..bc6828c7d0c31 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MaxBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MaxBucketIT.java
@@ -32,13 +32,17 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregationBuilders;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.PipelineAggregatorBuilders;
@@ -54,12 +58,16 @@
 import org.opensearch.search.aggregations.metrics.SumAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.filter;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
@@ -72,7 +80,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class MaxBucketIT extends OpenSearchIntegTestCase {
+public class MaxBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -83,6 +91,23 @@ public class MaxBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public MaxBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
@@ -585,7 +610,8 @@ public void testFieldIsntWrittenOutTwice() throws Exception {
         groupByLicenseAgg.subAggregation(peakPipelineAggBuilder);
 
         SearchResponse response = client().prepareSearch("foo_*").setSize(0).addAggregation(groupByLicenseAgg).get();
-        BytesReference bytes = XContentHelper.toXContent(response, XContentType.JSON, false);
-        XContentHelper.convertToMap(bytes, false, XContentType.JSON);
+        BytesReference bytes = org.opensearch.core.xcontent.XContentHelper.toXContent(response, MediaTypeRegistry.JSON, false);
+        XContentHelper.convertToMap(bytes, false, MediaTypeRegistry.JSON);
+        internalCluster().wipeIndices("foo_*");
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MinBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MinBucketIT.java
index b3929943f0d02..3c8d3e2064014 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MinBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MinBucketIT.java
@@ -32,21 +32,29 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
-import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
+import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
-import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -58,7 +66,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class MinBucketIT extends OpenSearchIntegTestCase {
+public class MinBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -69,6 +77,23 @@ public class MinBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public MinBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MovAvgIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MovAvgIT.java
index 91390edc7e872..0cf89778c6e99 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MovAvgIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MovAvgIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.bulk.BulkRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -40,13 +42,15 @@
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.client.Client;
 import org.opensearch.common.collect.EvictingQueue;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
 import org.opensearch.search.aggregations.metrics.Avg;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
@@ -58,6 +62,7 @@
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
@@ -72,7 +77,7 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class MovAvgIT extends OpenSearchIntegTestCase {
+public class MovAvgIT extends ParameterizedOpenSearchIntegTestCase {
     private static final String INTERVAL_FIELD = "l_value";
     private static final String VALUE_FIELD = "v_value";
     private static final String VALUE_FIELD2 = "v_value2";
@@ -128,6 +133,23 @@ public String toString() {
         }
     }
 
+    public MovAvgIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         prepareCreate("idx").setMapping(
@@ -1342,6 +1364,7 @@ public void testPredictWithNonEmptyBuckets() throws Exception {
                 assertThat(movAvgAgg, nullValue());
             }
         }
+        internalCluster().wipeIndices("predict_non_empty");
     }
 
     private void assertValidIterators(Iterator expectedBucketIter, Iterator expectedCountsIter, Iterator expectedValuesIter) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketIT.java
index 1da079781dc63..580497715ed6d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
@@ -43,14 +47,17 @@
 import org.opensearch.search.aggregations.metrics.Percentile;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -62,7 +69,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class PercentilesBucketIT extends OpenSearchIntegTestCase {
+public class PercentilesBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
     private static final double[] PERCENTS = { 0.0, 1.0, 25.0, 50.0, 75.0, 99.0, 100.0 };
@@ -73,6 +80,23 @@ public class PercentilesBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public PercentilesBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SerialDiffIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SerialDiffIT.java
index f5a5d025946ec..b4da63802bc50 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SerialDiffIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SerialDiffIT.java
@@ -32,22 +32,30 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.collect.EvictingQueue;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
@@ -61,7 +69,7 @@
 import static org.hamcrest.core.IsNull.nullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class SerialDiffIT extends OpenSearchIntegTestCase {
+public class SerialDiffIT extends ParameterizedOpenSearchIntegTestCase {
     private static final String INTERVAL_FIELD = "l_value";
     private static final String VALUE_FIELD = "v_value";
 
@@ -90,6 +98,23 @@ public String toString() {
         }
     }
 
+    public SerialDiffIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private ValuesSourceAggregationBuilder<? extends ValuesSourceAggregationBuilder<?>> randomMetric(String name, String field) {
         int rand = randomIntBetween(0, 3);
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/StatsBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/StatsBucketIT.java
index e9f34f6aa65d9..21fdd5e761e77 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/StatsBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/StatsBucketIT.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
@@ -42,11 +46,15 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -58,10 +66,9 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class StatsBucketIT extends OpenSearchIntegTestCase {
+public class StatsBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
-
     static int numDocs;
     static int interval;
     static int minRandomValue;
@@ -69,6 +76,23 @@ public class StatsBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public StatsBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SumBucketIT.java b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SumBucketIT.java
index 5bd962017c247..d4bd8f21b2a99 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SumBucketIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/SumBucketIT.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram.Bucket;
@@ -42,11 +46,15 @@
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.sum;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
@@ -58,7 +66,7 @@
 import static org.hamcrest.core.IsNull.notNullValue;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class SumBucketIT extends OpenSearchIntegTestCase {
+public class SumBucketIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
 
@@ -69,6 +77,23 @@ public class SumBucketIT extends OpenSearchIntegTestCase {
     static int numValueBuckets;
     static long[] valueCounts;
 
+    public SumBucketIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("idx").setMapping("tag", "type=keyword").get());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/backpressure/SearchBackpressureIT.java b/server/src/internalClusterTest/java/org/opensearch/search/backpressure/SearchBackpressureIT.java
new file mode 100644
index 0000000000000..28ada82a1c56b
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/backpressure/SearchBackpressureIT.java
@@ -0,0 +1,477 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.ActionType;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.plugins.ActionPlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.search.backpressure.settings.NodeDuressSettings;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
+public class SearchBackpressureIT extends ParameterizedOpenSearchIntegTestCase {
+
+    private static final TimeValue TIMEOUT = new TimeValue(10, TimeUnit.SECONDS);
+    private static final int MOVING_AVERAGE_WINDOW_SIZE = 10;
+
+    public SearchBackpressureIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        final List<Class<? extends Plugin>> plugins = new ArrayList<>(super.nodePlugins());
+        plugins.add(TestPlugin.class);
+        return plugins;
+    }
+
+    @Before
+    public final void setupNodeSettings() {
+        Settings request = Settings.builder()
+            .put(NodeDuressSettings.SETTING_CPU_THRESHOLD.getKey(), 0.0)
+            .put(NodeDuressSettings.SETTING_HEAP_THRESHOLD.getKey(), 0.0)
+            .put(NodeDuressSettings.SETTING_NUM_SUCCESSIVE_BREACHES.getKey(), 1)
+            .put(SearchTaskSettings.SETTING_TOTAL_HEAP_PERCENT_THRESHOLD.getKey(), 0.0)
+            .put(SearchShardTaskSettings.SETTING_TOTAL_HEAP_PERCENT_THRESHOLD.getKey(), 0.0)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+    }
+
+    @After
+    public final void cleanupNodeSettings() {
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().putNull("*"))
+                .setTransientSettings(Settings.builder().putNull("*"))
+        );
+    }
+
+    public void testCancellationSettingsChanged() {
+        Settings request = Settings.builder().put(SearchTaskSettings.SETTING_CANCELLATION_RATE.getKey(), "0.05").build();
+        ClusterUpdateSettingsResponse response = client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get();
+        assertEquals(response.getPersistentSettings().get(SearchTaskSettings.SETTING_CANCELLATION_RATE.getKey()), "0.05");
+
+        request = Settings.builder().put(SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.getKey(), "0.7").build();
+        response = client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get();
+        assertEquals(response.getPersistentSettings().get(SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.getKey()), "0.7");
+    }
+
+    public void testSearchTaskCancellationWithHighElapsedTime() throws InterruptedException {
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.getKey(), 1000)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        client().execute(
+            TestTransportAction.ACTION,
+            new TestRequest<>(
+                RequestType.HIGH_ELAPSED_TIME,
+                (TaskFactory<Task>) (id, type, action, description, parentTaskId, headers) -> new SearchTask(
+                    id,
+                    type,
+                    action,
+                    descriptionSupplier(description),
+                    parentTaskId,
+                    headers
+                )
+            ),
+            listener
+        );
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("elapsed time exceeded"));
+    }
+
+    public void testSearchShardTaskCancellationWithHighElapsedTime() throws InterruptedException {
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchShardTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.getKey(), 1000)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        client().execute(TestTransportAction.ACTION, new TestRequest<>(RequestType.HIGH_ELAPSED_TIME, SearchShardTask::new), listener);
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchShardTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("elapsed time exceeded"));
+    }
+
+    public void testSearchTaskCancellationWithHighCpu() throws InterruptedException {
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD.getKey(), 1000)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        client().execute(
+            TestTransportAction.ACTION,
+            new TestRequest<>(
+                RequestType.HIGH_CPU,
+                (TaskFactory<Task>) (id, type, action, description, parentTaskId, headers) -> new SearchTask(
+                    id,
+                    type,
+                    action,
+                    descriptionSupplier(description),
+                    parentTaskId,
+                    headers
+                )
+            ),
+            listener
+        );
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("cpu usage exceeded"));
+    }
+
+    public void testSearchShardTaskCancellationWithHighCpu() throws InterruptedException {
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchShardTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD.getKey(), 1000)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        client().execute(TestTransportAction.ACTION, new TestRequest<>(RequestType.HIGH_CPU, SearchShardTask::new), listener);
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchShardTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("cpu usage exceeded"));
+    }
+
+    public void testSearchTaskCancellationWithHighHeapUsage() throws InterruptedException {
+        // Before SearchBackpressureService cancels a task based on its heap usage, we need to build up the heap moving average
+        // To build up the heap moving average, we need to hit the same node with multiple requests and then hit the same node with a
+        // request having higher heap usage
+        String node = randomFrom(internalCluster().getNodeNames());
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchTaskSettings.SETTING_HEAP_PERCENT_THRESHOLD.getKey(), 0.0)
+            .put(SearchTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD.getKey(), 1.0)
+            .put(SearchTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.getKey(), MOVING_AVERAGE_WINDOW_SIZE)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        for (int i = 0; i < MOVING_AVERAGE_WINDOW_SIZE; i++) {
+            client(node).execute(
+                TestTransportAction.ACTION,
+                new TestRequest<>(
+                    RequestType.HIGH_HEAP,
+                    (TaskFactory<Task>) (id, type, action, description, parentTaskId, headers) -> new SearchTask(
+                        id,
+                        type,
+                        action,
+                        descriptionSupplier(description),
+                        parentTaskId,
+                        headers
+                    )
+                ),
+                listener
+            );
+        }
+
+        listener = new ExceptionCatchingListener();
+        client(node).execute(
+            TestTransportAction.ACTION,
+            new TestRequest<>(
+                RequestType.HIGHER_HEAP,
+                (TaskFactory<Task>) (id, type, action, description, parentTaskId, headers) -> new SearchTask(
+                    id,
+                    type,
+                    action,
+                    descriptionSupplier(description),
+                    parentTaskId,
+                    headers
+                )
+            ),
+            listener
+        );
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("heap usage exceeded"));
+    }
+
+    public void testSearchShardTaskCancellationWithHighHeapUsage() throws InterruptedException {
+        // Before SearchBackpressureService cancels a task based on its heap usage, we need to build up the heap moving average
+        // To build up the heap moving average, we need to hit the same node with multiple requests and then hit the same node with a
+        // request having higher heap usage
+        String node = randomFrom(internalCluster().getNodeNames());
+        Settings request = Settings.builder()
+            .put(SearchBackpressureSettings.SETTING_MODE.getKey(), "enforced")
+            .put(SearchShardTaskSettings.SETTING_HEAP_PERCENT_THRESHOLD.getKey(), 0.0)
+            .put(SearchShardTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD.getKey(), 1.0)
+            .put(SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.getKey(), MOVING_AVERAGE_WINDOW_SIZE)
+            .build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        for (int i = 0; i < MOVING_AVERAGE_WINDOW_SIZE; i++) {
+            client(node).execute(TestTransportAction.ACTION, new TestRequest<>(RequestType.HIGH_HEAP, SearchShardTask::new), listener);
+        }
+
+        listener = new ExceptionCatchingListener();
+        client(node).execute(TestTransportAction.ACTION, new TestRequest<>(RequestType.HIGHER_HEAP, SearchShardTask::new), listener);
+        assertTrue(listener.latch.await(TIMEOUT.getSeconds(), TimeUnit.SECONDS));
+
+        Exception caughtException = listener.getException();
+        assertNotNull("SearchShardTask should have been cancelled with TaskCancelledException", caughtException);
+        MatcherAssert.assertThat(caughtException, instanceOf(TaskCancelledException.class));
+        MatcherAssert.assertThat(caughtException.getMessage(), containsString("heap usage exceeded"));
+    }
+
+    public void testSearchCancellationWithBackpressureDisabled() throws InterruptedException {
+        Settings request = Settings.builder().put(SearchBackpressureSettings.SETTING_MODE.getKey(), "monitor_only").build();
+        assertAcked(client().admin().cluster().prepareUpdateSettings().setPersistentSettings(request).get());
+
+        ExceptionCatchingListener listener = new ExceptionCatchingListener();
+        client().execute(TestTransportAction.ACTION, new TestRequest<>(RequestType.HIGH_ELAPSED_TIME, SearchShardTask::new), listener);
+        // waiting for the TIMEOUT * 3 time for the request to complete and the latch to countdown.
+        assertTrue(
+            "SearchShardTask should have been completed by now and countdown the latch",
+            listener.latch.await(TIMEOUT.getSeconds() * 3, TimeUnit.SECONDS)
+        );
+
+        Exception caughtException = listener.getException();
+        assertNull("SearchShardTask shouldn't have cancelled for monitor_only mode", caughtException);
+    }
+
+    private static class ExceptionCatchingListener implements ActionListener<TestResponse> {
+        private final CountDownLatch latch;
+        private Exception exception = null;
+
+        public ExceptionCatchingListener() {
+            this.latch = new CountDownLatch(1);
+        }
+
+        @Override
+        public void onResponse(TestResponse r) {
+            latch.countDown();
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            this.exception = e;
+            latch.countDown();
+        }
+
+        private Exception getException() {
+            return exception;
+        }
+    }
+
+    enum RequestType {
+        HIGH_CPU,
+        HIGH_HEAP,
+        HIGHER_HEAP,
+        HIGH_ELAPSED_TIME;
+    }
+
+    private Supplier<String> descriptionSupplier(String description) {
+        return () -> description;
+    }
+
+    interface TaskFactory<T extends Task> {
+        T createTask(long id, String type, String action, String description, TaskId parentTaskId, Map<String, String> headers);
+    }
+
+    public static class TestRequest<T extends Task> extends ActionRequest {
+        private final RequestType type;
+        private TaskFactory<T> taskFactory;
+
+        public TestRequest(RequestType type, TaskFactory<T> taskFactory) {
+            this.type = type;
+            this.taskFactory = taskFactory;
+        }
+
+        public TestRequest(StreamInput in) throws IOException {
+            super(in);
+            this.type = in.readEnum(RequestType.class);
+        }
+
+        @Override
+        public ActionRequestValidationException validate() {
+            return null;
+        }
+
+        @Override
+        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+            return taskFactory.createTask(id, type, action, "", parentTaskId, headers);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeEnum(type);
+        }
+
+        public RequestType getType() {
+            return this.type;
+        }
+    }
+
+    public static class TestResponse extends ActionResponse {
+        public TestResponse() {}
+
+        public TestResponse(StreamInput in) {}
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {}
+    }
+
+    public static class TestTransportAction extends HandledTransportAction<TestRequest, TestResponse> {
+        public static final ActionType<TestResponse> ACTION = new ActionType<>("internal::test_action", TestResponse::new);
+        private final ThreadPool threadPool;
+
+        @Inject
+        public TestTransportAction(TransportService transportService, ThreadPool threadPool, ActionFilters actionFilters) {
+            super(ACTION.name(), transportService, actionFilters, TestRequest::new);
+            this.threadPool = threadPool;
+        }
+
+        @Override
+        protected void doExecute(Task task, TestRequest request, ActionListener<TestResponse> listener) {
+            threadPool.executor(ThreadPool.Names.SEARCH).execute(() -> {
+                try {
+                    CancellableTask cancellableTask = (CancellableTask) task;
+                    long startTime = System.nanoTime();
+
+                    // Doing a busy-wait until task cancellation or timeout.
+                    // We are running HIGH_HEAP requests to build up heap moving average and not expect it to get cancelled.
+                    do {
+                        doWork(request);
+                    } while (request.type != RequestType.HIGH_HEAP
+                        && cancellableTask.isCancelled() == false
+                        && (System.nanoTime() - startTime) < TIMEOUT.getNanos());
+
+                    if (cancellableTask.isCancelled()) {
+                        throw new TaskCancelledException(cancellableTask.getReasonCancelled());
+                    } else {
+                        listener.onResponse(new TestResponse());
+                    }
+                } catch (Exception e) {
+                    listener.onFailure(e);
+                }
+            });
+        }
+
+        private void doWork(TestRequest<Task> request) throws InterruptedException {
+            switch (request.getType()) {
+                case HIGH_CPU:
+                    long i = 0, j = 1, k = 1, iterations = 1000;
+                    do {
+                        j += i;
+                        k *= j;
+                        i++;
+                    } while (i < iterations);
+                    break;
+                case HIGH_HEAP:
+                    Byte[] bytes = new Byte[100000];
+                    int[] ints = new int[1000];
+                    break;
+                case HIGHER_HEAP:
+                    Byte[] more_bytes = new Byte[1000000];
+                    int[] more_ints = new int[10000];
+                    break;
+                case HIGH_ELAPSED_TIME:
+                    Thread.sleep(100);
+                    break;
+            }
+        }
+    }
+
+    public static class TestPlugin extends Plugin implements ActionPlugin {
+        @Override
+        public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
+            return Collections.singletonList(new ActionHandler<>(TestTransportAction.ACTION, TestTransportAction.class));
+        }
+
+        @Override
+        public List<ActionType<? extends ActionResponse>> getClientActions() {
+            return Collections.singletonList(TestTransportAction.ACTION);
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchRedStateIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchRedStateIndexIT.java
index 3c2aa6642633e..44c4981dfdb36 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchRedStateIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchRedStateIndexIT.java
@@ -32,8 +32,9 @@
 
 package org.opensearch.search.basic;
 
-import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
@@ -41,14 +42,18 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.search.SearchService;
 import org.opensearch.test.OpenSearchIntegTestCase;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.After;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -56,7 +61,24 @@
 import static org.hamcrest.Matchers.lessThan;
 
 @OpenSearchIntegTestCase.ClusterScope(minNumDataNodes = 2)
-public class SearchRedStateIndexIT extends OpenSearchIntegTestCase {
+public class SearchRedStateIndexIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchRedStateIndexIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testAllowPartialsWithRedState() throws Exception {
         final int numShards = cluster().numDataNodes() + 2;
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileCreatingIndexIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileCreatingIndexIT.java
index 1d8512e101f78..71af7215c4eb7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileCreatingIndexIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileCreatingIndexIT.java
@@ -32,13 +32,21 @@
 
 package org.opensearch.search.basic;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 
@@ -46,7 +54,25 @@
  * This test basically verifies that search with a single shard active (cause we indexed to it) and other
  * shards possibly not active at all (cause they haven't allocated) will still work.
  */
-public class SearchWhileCreatingIndexIT extends OpenSearchIntegTestCase {
+public class SearchWhileCreatingIndexIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchWhileCreatingIndexIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testIndexCausesIndexCreation() throws Exception {
         searchWhileCreatingIndex(false, 1); // 1 replica in our default...
     }
@@ -88,8 +114,13 @@ private void searchWhileCreatingIndex(boolean createIndex, int numberOfReplicas)
         ClusterHealthStatus status = client().admin().cluster().prepareHealth("test").get().getStatus();
         while (status != ClusterHealthStatus.GREEN) {
             // first, verify that search normal search works
-            SearchResponse searchResponse = client().prepareSearch("test").setQuery(QueryBuilders.termQuery("field", "test")).get();
+            SearchResponse searchResponse = client().prepareSearch("test")
+                .setPreference("_primary")
+                .setQuery(QueryBuilders.termQuery("field", "test"))
+                .execute()
+                .actionGet();
             assertHitCount(searchResponse, 1);
+
             Client client = client();
             searchResponse = client.prepareSearch("test")
                 .setPreference(preference + Integer.toString(counter++))
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileRelocatingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileRelocatingIT.java
index c184d876dcb33..4f0dda9adfa52 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileRelocatingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileRelocatingIT.java
@@ -32,28 +32,52 @@
 
 package org.opensearch.search.basic;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.SearchHits;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoTimeout;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.formatShardStatus;
 import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.ClusterScope(minNumDataNodes = 2)
-public class SearchWhileRelocatingIT extends OpenSearchIntegTestCase {
+public class SearchWhileRelocatingIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchWhileRelocatingIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testSearchAndRelocateConcurrentlyRandomReplicas() throws Exception {
         testSearchAndRelocateConcurrently(randomIntBetween(0, 1));
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomExceptionsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomExceptionsIT.java
index 0b55ea9119d89..aa82b9d21c7fb 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomExceptionsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomExceptionsIT.java
@@ -32,29 +32,31 @@
 
 package org.opensearch.search.basic;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.tests.util.English;
-
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.index.MockEngineFactoryPlugin;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.engine.MockEngineSupport;
 import org.opensearch.test.engine.ThrowingLeafReaderWrapper;
 
@@ -66,9 +68,27 @@
 import java.util.Random;
 import java.util.concurrent.ExecutionException;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 
-public class SearchWithRandomExceptionsIT extends OpenSearchIntegTestCase {
+public class SearchWithRandomExceptionsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchWithRandomExceptionsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -81,16 +101,15 @@ protected boolean addMockInternalEngine() {
     }
 
     public void testRandomExceptions() throws IOException, InterruptedException, ExecutionException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("test")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("test")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         final double lowLevelRate;
         final double topLevelRate;
         if (frequently()) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomIOExceptionsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomIOExceptionsIT.java
index b0adc00f37fee..446a0bce58d66 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomIOExceptionsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWithRandomIOExceptionsIT.java
@@ -32,8 +32,9 @@
 
 package org.opensearch.search.basic;
 
-import org.apache.lucene.tests.util.English;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
+import org.apache.lucene.tests.util.English;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -42,14 +43,15 @@
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.client.Requests;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.store.MockFSDirectoryFactory;
 import org.opensearch.test.store.MockFSIndexStore;
 
@@ -58,10 +60,28 @@
 import java.util.Collection;
 import java.util.concurrent.ExecutionException;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 
-public class SearchWithRandomIOExceptionsIT extends OpenSearchIntegTestCase {
+public class SearchWithRandomIOExceptionsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchWithRandomIOExceptionsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -69,16 +89,15 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     public void testRandomDirectoryIOExceptions() throws IOException, InterruptedException, ExecutionException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("test")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("test")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         final double exceptionRate;
         final double exceptionOnOpenRate;
         if (frequently()) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportSearchFailuresIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportSearchFailuresIT.java
index 34b202cc09cf7..cbe52abf5279b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportSearchFailuresIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportSearchFailuresIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.basic;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
@@ -41,23 +43,46 @@
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.client.Requests.clusterHealthRequest;
 import static org.opensearch.client.Requests.refreshRequest;
 import static org.opensearch.client.Requests.searchRequest;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class TransportSearchFailuresIT extends OpenSearchIntegTestCase {
+public class TransportSearchFailuresIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public TransportSearchFailuresIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected int maximumNumberOfReplicas() {
         return 1;
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportTwoNodesSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportTwoNodesSearchIT.java
index 5cd6e76e1e487..ce5f3f63faa66 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportTwoNodesSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/basic/TransportTwoNodesSearchIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.basic;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.search.MultiSearchResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
@@ -39,7 +41,8 @@
 import org.opensearch.client.Requests;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.functionscore.ScriptScoreFunctionBuilder;
@@ -51,9 +54,11 @@
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Set;
 import java.util.TreeSet;
@@ -66,6 +71,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.Matchers.equalTo;
@@ -74,7 +80,24 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.startsWith;
 
-public class TransportTwoNodesSearchIT extends OpenSearchIntegTestCase {
+public class TransportTwoNodesSearchIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public TransportTwoNodesSearchIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected int numberOfReplicas() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fetch/FetchSubPhasePluginIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fetch/FetchSubPhasePluginIT.java
index def247676ac1a..86df25c4dad65 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fetch/FetchSubPhasePluginIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fetch/FetchSubPhasePluginIT.java
@@ -32,28 +32,33 @@
 
 package org.opensearch.search.fetch;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -64,11 +69,30 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.client.Requests.indexRequest;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.CoreMatchers.equalTo;
 
 @ClusterScope(scope = Scope.SUITE, supportsDedicatedMasters = false, numDataNodes = 2)
-public class FetchSubPhasePluginIT extends OpenSearchIntegTestCase {
+public class FetchSubPhasePluginIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public FetchSubPhasePluginIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singletonList(FetchTermVectorsPlugin.class);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/InnerHitsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/InnerHitsIT.java
index 837e1e7e23ddf..9b3e1337418cc 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/InnerHitsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/InnerHitsIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.fetch.subphase;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -39,7 +41,8 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
@@ -54,8 +57,8 @@
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -72,6 +75,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.nestedQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -84,7 +88,24 @@
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 
-public class InnerHitsIT extends OpenSearchIntegTestCase {
+public class InnerHitsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public InnerHitsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/MatchedQueriesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/MatchedQueriesIT.java
index 488c253535827..23b5d0cab0697 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/MatchedQueriesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/MatchedQueriesIT.java
@@ -32,16 +32,23 @@
 
 package org.opensearch.search.fetch.subphase;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.TermQueryBuilder;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.index.query.QueryBuilders.boolQuery;
 import static org.opensearch.index.query.QueryBuilders.constantScoreQuery;
@@ -52,11 +59,30 @@
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.index.query.QueryBuilders.termsQuery;
 import static org.opensearch.index.query.QueryBuilders.wrapperQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItemInArray;
 
-public class MatchedQueriesIT extends OpenSearchIntegTestCase {
+public class MatchedQueriesIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MatchedQueriesIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testSimpleMatchedQueryFromFilteredQuery() throws Exception {
         createIndex("test");
         ensureGreen();
@@ -328,6 +354,7 @@ public void testMatchedWithShould() throws Exception {
                         .should(queryStringQuery("dolor").queryName("dolor"))
                         .should(queryStringQuery("elit").queryName("elit"))
                 )
+                .setPreference("_primary")
                 .get();
 
             assertHitCount(searchResponse, 2L);
@@ -353,9 +380,9 @@ public void testMatchedWithWrapperQuery() throws Exception {
         refresh();
 
         MatchQueryBuilder matchQueryBuilder = matchQuery("content", "amet").queryName("abc");
-        BytesReference matchBytes = XContentHelper.toXContent(matchQueryBuilder, XContentType.JSON, false);
+        BytesReference matchBytes = XContentHelper.toXContent(matchQueryBuilder, MediaTypeRegistry.JSON, false);
         TermQueryBuilder termQueryBuilder = termQuery("content", "amet").queryName("abc");
-        BytesReference termBytes = XContentHelper.toXContent(termQueryBuilder, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQueryBuilder, MediaTypeRegistry.JSON, false);
         QueryBuilder[] queries = new QueryBuilder[] { wrapperQuery(matchBytes), constantScoreQuery(wrapperQuery(termBytes)) };
         for (QueryBuilder query : queries) {
             SearchResponse searchResponse = client().prepareSearch().setQuery(query).get();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighterSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighterSearchIT.java
index 7df5b9b88a69c..fe17c3e22d43c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighterSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighterSearchIT.java
@@ -31,12 +31,16 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.io.IOException;
@@ -45,6 +49,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHighlight;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -52,7 +57,24 @@
  * Integration test for highlighters registered by a plugin.
  */
 @ClusterScope(scope = Scope.SUITE, supportsDedicatedMasters = false, numDataNodes = 1)
-public class CustomHighlighterSearchIT extends OpenSearchIntegTestCase {
+public class CustomHighlighterSearchIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public CustomHighlighterSearchIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/HighlighterSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/HighlighterSearchIT.java
index 193a48cf0daa6..4cdf5ae8e674f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/HighlighterSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fetch/subphase/highlight/HighlighterSearchIT.java
@@ -31,26 +31,28 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockAnalyzer;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.search.join.ScoreMode;
-
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.AbstractIndexAnalyzerProvider;
 import org.opensearch.index.analysis.AnalyzerProvider;
 import org.opensearch.index.analysis.PreConfiguredTokenFilter;
@@ -65,17 +67,15 @@
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.plugins.AnalysisPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder.BoundaryScannerType;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder.Field;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.MockKeywordPlugin;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
 
@@ -109,6 +109,7 @@
 import static org.opensearch.index.query.QueryBuilders.regexpQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.index.query.QueryBuilders.wildcardQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.highlight;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -127,10 +128,28 @@
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.startsWith;
 
-public class HighlighterSearchIT extends OpenSearchIntegTestCase {
+public class HighlighterSearchIT extends ParameterizedOpenSearchIntegTestCase {
+
     // TODO as we move analyzers out of the core we need to move some of these into HighlighterWithAnalyzersTests
     private static final String[] ALL_TYPES = new String[] { "plain", "fvh", "unified" };
 
+    public HighlighterSearchIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(InternalSettingsPlugin.class, MockKeywordPlugin.class, MockAnalysisPlugin.class);
@@ -3231,26 +3250,25 @@ public void testCopyToFields() throws Exception {
     }
 
     public void testACopyFieldWithNestedQuery() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "nested")
-                .startObject("properties")
-                .startObject("text")
-                .field("type", "text")
-                .field("copy_to", "foo_text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .startObject("foo_text")
-                .field("type", "text")
-                .field("term_vector", "with_positions_offsets")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "nested")
+            .startObject("properties")
+            .startObject("text")
+            .field("type", "text")
+            .field("copy_to", "foo_text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .startObject("foo_text")
+            .field("type", "text")
+            .field("term_vector", "with_positions_offsets")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         prepareCreate("test").setMapping(mapping).get();
 
         client().prepareIndex("test")
@@ -3361,25 +3379,24 @@ public void testHighlightQueryRewriteDatesWithNow() throws Exception {
     }
 
     public void testWithNestedQuery() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("text")
-                .field("type", "text")
-                .field("index_options", "offsets")
-                .field("term_vector", "with_positions_offsets")
-                .endObject()
-                .startObject("foo")
-                .field("type", "nested")
-                .startObject("properties")
-                .startObject("text")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("text")
+            .field("type", "text")
+            .field("index_options", "offsets")
+            .field("term_vector", "with_positions_offsets")
+            .endObject()
+            .startObject("foo")
+            .field("type", "nested")
+            .startObject("properties")
+            .startObject("text")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         prepareCreate("test").setMapping(mapping).get();
 
         client().prepareIndex("test")
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fieldcaps/FieldCapabilitiesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fieldcaps/FieldCapabilitiesIT.java
index dacf388e2faa0..f5d1b8234558e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fieldcaps/FieldCapabilitiesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fieldcaps/FieldCapabilitiesIT.java
@@ -32,15 +32,19 @@
 
 package org.opensearch.search.fieldcaps;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.fieldcaps.FieldCapabilities;
 import org.opensearch.action.fieldcaps.FieldCapabilitiesResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.MapperPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.util.ArrayList;
@@ -52,9 +56,27 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 
-public class FieldCapabilitiesIT extends OpenSearchIntegTestCase {
+public class FieldCapabilitiesIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public FieldCapabilitiesIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Before
     public void setUp() throws Exception {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/fields/SearchFieldsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/fields/SearchFieldsIT.java
index 25782f8dc18db..799bbf91a567d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/fields/SearchFieldsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/fields/SearchFieldsIT.java
@@ -32,26 +32,29 @@
 
 package org.opensearch.search.fields;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -59,13 +62,13 @@
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.lookup.FieldLookup;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
 import org.joda.time.format.DateTimeFormat;
 
+import java.math.BigInteger;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
@@ -88,6 +91,7 @@
 import static org.opensearch.common.util.set.Sets.newHashSet;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -100,7 +104,24 @@
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 
-public class SearchFieldsIT extends OpenSearchIntegTestCase {
+public class SearchFieldsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchFieldsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -113,6 +134,20 @@ public static class CustomScriptPlugin extends MockScriptPlugin {
         protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
             Map<String, Function<Map<String, Object>, Object>> scripts = new HashMap<>();
 
+            scripts.put("doc['unsigned_num1'].value", vars -> {
+                Map<?, ?> doc = (Map) vars.get("doc");
+                ScriptDocValues.UnsignedLongs num1 = (ScriptDocValues.UnsignedLongs) doc.get("unsigned_num1");
+                return num1.getValue();
+            });
+
+            scripts.put("doc['unsigned_num1'].value * factor", vars -> {
+                Map<?, ?> doc = (Map) vars.get("doc");
+                ScriptDocValues.UnsignedLongs num1 = (ScriptDocValues.UnsignedLongs) doc.get("unsigned_num1");
+                Map<String, Object> params = (Map<String, Object>) vars.get("params");
+                Double factor = (Double) params.get("factor");
+                return num1.getValue().multiply(Numbers.toBigIntegerExact(factor));
+            });
+
             scripts.put("doc['num1'].value", vars -> {
                 Map<?, ?> doc = (Map) vars.get("doc");
                 ScriptDocValues.Doubles num1 = (ScriptDocValues.Doubles) doc.get("num1");
@@ -140,9 +175,9 @@ protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
             });
 
             scripts.put("_fields['num1'].value", vars -> fieldsScript(vars, "num1"));
+            scripts.put("_fields['unsigned_num1'].value", vars -> fieldsScript(vars, "unsigned_num1"));
             scripts.put("_fields._uid.value", vars -> fieldsScript(vars, "_uid"));
             scripts.put("_fields._id.value", vars -> fieldsScript(vars, "_id"));
-            scripts.put("_fields._type.value", vars -> fieldsScript(vars, "_type"));
 
             scripts.put("_source.obj1", vars -> sourceScript(vars, "obj1"));
             scripts.put("_source.obj1.test", vars -> sourceScript(vars, "obj1.test"));
@@ -185,29 +220,28 @@ static Object docScript(Map<String, Object> vars, String fieldName) {
     public void testStoredFields() throws Exception {
         createIndex("test");
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "text")
-                .field("store", true)
-                .endObject()
-                .startObject("field2")
-                .field("type", "text")
-                .field("store", false)
-                .endObject()
-                .startObject("field3")
-                .field("type", "text")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "text")
+            .field("store", true)
+            .endObject()
+            .startObject("field2")
+            .field("type", "text")
+            .field("store", false)
+            .endObject()
+            .startObject("field3")
+            .field("type", "text")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
-        client().admin().indices().preparePutMapping().setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
 
         client().prepareIndex("test")
             .setId("1")
@@ -288,21 +322,20 @@ public void testStoredFields() throws Exception {
     public void testScriptDocAndFields() throws Exception {
         createIndex("test");
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("num1")
-                .field("type", "double")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("num1")
+            .field("type", "double")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
-        client().admin().indices().preparePutMapping().setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
 
         client().prepareIndex("test")
             .setId("1")
@@ -387,23 +420,124 @@ public void testScriptDocAndFields() throws Exception {
         assertThat(response.getHits().getAt(2).getFields().get("sNum1").getValues().get(0), equalTo(6.0));
     }
 
-    public void testScriptFieldWithNanos() throws Exception {
+    public void testScriptWithUnsignedLong() throws Exception {
         createIndex("test");
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("date")
-                .field("type", "date_nanos")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("unsigned_num1")
+            .field("type", "unsigned_long")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
+
+        client().prepareIndex("test")
+            .setId("1")
+            .setSource(jsonBuilder().startObject().field("test", "value beck").field("unsigned_num1", BigInteger.valueOf(1)).endObject())
+            .get();
+        client().admin().indices().prepareFlush().get();
+        client().prepareIndex("test")
+            .setId("2")
+            .setSource(jsonBuilder().startObject().field("test", "value beck").field("unsigned_num1", BigInteger.valueOf(2)).endObject())
+            .get();
+        client().admin().indices().prepareFlush().get();
+        client().prepareIndex("test")
+            .setId("3")
+            .setSource(
+                jsonBuilder().startObject()
+                    .field("test", "value beck")
+                    .field("unsigned_num1", new BigInteger("9322337203685477580"))
+                    .endObject()
+            )
+            .get();
+        client().admin().indices().refresh(refreshRequest()).actionGet();
+
+        SearchResponse response = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort("unsigned_num1", SortOrder.ASC)
+            .addScriptField(
+                "sNum1",
+                new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "doc['unsigned_num1'].value", Collections.emptyMap())
+            )
+            .addScriptField(
+                "sNum1_field",
+                new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_fields['unsigned_num1'].value", Collections.emptyMap())
+            )
+            .get();
+
+        assertNoFailures(response);
+
+        logger.info("running doc['unsigned_num1'].value");
+        assertThat(response.getHits().getTotalHits().value, equalTo(3L));
+        assertFalse(response.getHits().getAt(0).hasSource());
+        assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
+        Set<String> fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(newHashSet("sNum1", "sNum1_field")));
+        assertThat(response.getHits().getAt(0).getFields().get("sNum1").getValues().get(0), equalTo(BigInteger.valueOf(1)));
+        assertThat(response.getHits().getAt(0).getFields().get("sNum1_field").getValues().get(0), equalTo(BigInteger.valueOf(1)));
+        assertThat(response.getHits().getAt(1).getId(), equalTo("2"));
+        fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(newHashSet("sNum1", "sNum1_field")));
+        assertThat(response.getHits().getAt(1).getFields().get("sNum1").getValues().get(0), equalTo(BigInteger.valueOf(2)));
+        assertThat(response.getHits().getAt(1).getFields().get("sNum1_field").getValues().get(0), equalTo(BigInteger.valueOf(2)));
+        assertThat(response.getHits().getAt(2).getId(), equalTo("3"));
+        fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(newHashSet("sNum1", "sNum1_field")));
+        assertThat(response.getHits().getAt(2).getFields().get("sNum1").getValues().get(0), equalTo(new BigInteger("9322337203685477580")));
+        assertThat(
+            response.getHits().getAt(2).getFields().get("sNum1_field").getValues().get(0),
+            equalTo(new BigInteger("9322337203685477580"))
+        );
+
+        logger.info("running doc['unsigned_num1'].value * factor");
+        Map<String, Object> params = MapBuilder.<String, Object>newMapBuilder().put("factor", 2.0).map();
+        response = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort("unsigned_num1", SortOrder.ASC)
+            .addScriptField("sNum1", new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "doc['unsigned_num1'].value * factor", params))
+            .get();
+
+        assertThat(response.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
+        fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(singleton("sNum1")));
+        assertThat(response.getHits().getAt(0).getFields().get("sNum1").getValues().get(0), equalTo(BigInteger.valueOf(2)));
+        assertThat(response.getHits().getAt(1).getId(), equalTo("2"));
+        fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(singleton("sNum1")));
+        assertThat(response.getHits().getAt(1).getFields().get("sNum1").getValues().get(0), equalTo(BigInteger.valueOf(4)));
+        assertThat(response.getHits().getAt(2).getId(), equalTo("3"));
+        fields = new HashSet<>(response.getHits().getAt(0).getFields().keySet());
+        assertThat(fields, equalTo(singleton("sNum1")));
+        assertThat(
+            response.getHits().getAt(2).getFields().get("sNum1").getValues().get(0),
+            equalTo(new BigInteger("18644674407370955160"))
         );
+    }
+
+    public void testScriptFieldWithNanos() throws Exception {
+        createIndex("test");
 
-        client().admin().indices().preparePutMapping().setSource(mapping, XContentType.JSON).get();
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("date")
+            .field("type", "date_nanos")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
         String date = "2019-01-31T10:00:00.123456789Z";
         indexRandom(
             true,
@@ -471,42 +605,6 @@ public void testIdBasedScriptFields() throws Exception {
             assertThat(fields, equalTo(singleton("id")));
             assertThat(response.getHits().getAt(i).getFields().get("id").getValue(), equalTo(Integer.toString(i)));
         }
-
-        response = client().prepareSearch()
-            .setQuery(matchAllQuery())
-            .addSort("num1", SortOrder.ASC)
-            .setSize(numDocs)
-            .addScriptField("type", new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_fields._type.value", Collections.emptyMap()))
-            .get();
-
-        assertNoFailures(response);
-
-        assertThat(response.getHits().getTotalHits().value, equalTo((long) numDocs));
-        for (int i = 0; i < numDocs; i++) {
-            assertThat(response.getHits().getAt(i).getId(), equalTo(Integer.toString(i)));
-            Set<String> fields = new HashSet<>(response.getHits().getAt(i).getFields().keySet());
-            assertThat(fields, equalTo(singleton("type")));
-            assertThat(response.getHits().getAt(i).getFields().get("type").getValue(), equalTo(MapperService.SINGLE_MAPPING_NAME));
-        }
-
-        response = client().prepareSearch()
-            .setQuery(matchAllQuery())
-            .addSort("num1", SortOrder.ASC)
-            .setSize(numDocs)
-            .addScriptField("id", new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_fields._id.value", Collections.emptyMap()))
-            .addScriptField("type", new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_fields._type.value", Collections.emptyMap()))
-            .get();
-
-        assertNoFailures(response);
-
-        assertThat(response.getHits().getTotalHits().value, equalTo((long) numDocs));
-        for (int i = 0; i < numDocs; i++) {
-            assertThat(response.getHits().getAt(i).getId(), equalTo(Integer.toString(i)));
-            Set<String> fields = new HashSet<>(response.getHits().getAt(i).getFields().keySet());
-            assertThat(fields, equalTo(newHashSet("type", "id")));
-            assertThat(response.getHits().getAt(i).getFields().get("type").getValue(), equalTo(MapperService.SINGLE_MAPPING_NAME));
-            assertThat(response.getHits().getAt(i).getFields().get("id").getValue(), equalTo(Integer.toString(i)));
-        }
     }
 
     public void testScriptFieldUsingSource() throws Exception {
@@ -623,56 +721,59 @@ public void testPartialFields() throws Exception {
     public void testStoredFieldsWithoutSource() throws Exception {
         createIndex("test");
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("_source")
-                .field("enabled", false)
-                .endObject()
-                .startObject("properties")
-                .startObject("byte_field")
-                .field("type", "byte")
-                .field("store", true)
-                .endObject()
-                .startObject("short_field")
-                .field("type", "short")
-                .field("store", true)
-                .endObject()
-                .startObject("integer_field")
-                .field("type", "integer")
-                .field("store", true)
-                .endObject()
-                .startObject("long_field")
-                .field("type", "long")
-                .field("store", true)
-                .endObject()
-                .startObject("float_field")
-                .field("type", "float")
-                .field("store", true)
-                .endObject()
-                .startObject("double_field")
-                .field("type", "double")
-                .field("store", true)
-                .endObject()
-                .startObject("date_field")
-                .field("type", "date")
-                .field("store", true)
-                .endObject()
-                .startObject("boolean_field")
-                .field("type", "boolean")
-                .field("store", true)
-                .endObject()
-                .startObject("binary_field")
-                .field("type", "binary")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("_source")
+            .field("enabled", false)
+            .endObject()
+            .startObject("properties")
+            .startObject("byte_field")
+            .field("type", "byte")
+            .field("store", true)
+            .endObject()
+            .startObject("short_field")
+            .field("type", "short")
+            .field("store", true)
+            .endObject()
+            .startObject("integer_field")
+            .field("type", "integer")
+            .field("store", true)
+            .endObject()
+            .startObject("long_field")
+            .field("type", "long")
+            .field("store", true)
+            .endObject()
+            .startObject("float_field")
+            .field("type", "float")
+            .field("store", true)
+            .endObject()
+            .startObject("double_field")
+            .field("type", "double")
+            .field("store", true)
+            .endObject()
+            .startObject("date_field")
+            .field("type", "date")
+            .field("store", true)
+            .endObject()
+            .startObject("boolean_field")
+            .field("type", "boolean")
+            .field("store", true)
+            .endObject()
+            .startObject("binary_field")
+            .field("type", "binary")
+            .field("store", true)
+            .endObject()
+            .startObject("unsigned_long_field")
+            .field("type", "unsigned_long")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
-        client().admin().indices().preparePutMapping().setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
 
         ZonedDateTime date = ZonedDateTime.of(2012, 3, 22, 0, 0, 0, 0, ZoneOffset.UTC);
         client().prepareIndex("test")
@@ -688,6 +789,7 @@ public void testStoredFieldsWithoutSource() throws Exception {
                     .field("date_field", DateFormatter.forPattern("date_optional_time").format(date))
                     .field("boolean_field", true)
                     .field("binary_field", Base64.getEncoder().encodeToString("testing text".getBytes("UTF-8")))
+                    .field("unsigned_long_field", new BigInteger("10223372036854775807"))
                     .endObject()
             )
             .get();
@@ -705,6 +807,7 @@ public void testStoredFieldsWithoutSource() throws Exception {
             .addStoredField("date_field")
             .addStoredField("boolean_field")
             .addStoredField("binary_field")
+            .addStoredField("unsigned_long_field")
             .get();
 
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
@@ -722,7 +825,8 @@ public void testStoredFieldsWithoutSource() throws Exception {
                     "double_field",
                     "date_field",
                     "boolean_field",
-                    "binary_field"
+                    "binary_field",
+                    "unsigned_long_field"
                 )
             )
         );
@@ -738,6 +842,7 @@ public void testStoredFieldsWithoutSource() throws Exception {
         assertThat(searchHit.getFields().get("date_field").getValue(), equalTo((Object) dateTime));
         assertThat(searchHit.getFields().get("boolean_field").getValue(), equalTo((Object) Boolean.TRUE));
         assertThat(searchHit.getFields().get("binary_field").getValue(), equalTo(new BytesArray("testing text".getBytes("UTF8"))));
+        assertThat(searchHit.getFields().get("unsigned_long_field").getValue(), equalTo(new BigInteger("10223372036854775807")));
     }
 
     public void testSearchFieldsMetadata() throws Exception {
@@ -826,7 +931,7 @@ public void testGetFieldsComplexField() throws Exception {
                 .endObject()
         );
 
-        client().prepareIndex("my-index").setId("1").setRefreshPolicy(IMMEDIATE).setSource(source, XContentType.JSON).get();
+        client().prepareIndex("my-index").setId("1").setRefreshPolicy(IMMEDIATE).setSource(source, MediaTypeRegistry.JSON).get();
 
         String field = "field1.field2.field3.field4";
 
@@ -853,58 +958,60 @@ public void testSingleValueFieldDatatField() throws ExecutionException, Interrup
     public void testDocValueFields() throws Exception {
         createIndex("test");
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("_source")
-                .field("enabled", false)
-                .endObject()
-                .startObject("properties")
-                .startObject("text_field")
-                .field("type", "text")
-                .field("fielddata", true)
-                .endObject()
-                .startObject("keyword_field")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("byte_field")
-                .field("type", "byte")
-                .endObject()
-                .startObject("short_field")
-                .field("type", "short")
-                .endObject()
-                .startObject("integer_field")
-                .field("type", "integer")
-                .endObject()
-                .startObject("long_field")
-                .field("type", "long")
-                .endObject()
-                .startObject("float_field")
-                .field("type", "float")
-                .endObject()
-                .startObject("double_field")
-                .field("type", "double")
-                .endObject()
-                .startObject("date_field")
-                .field("type", "date")
-                .endObject()
-                .startObject("boolean_field")
-                .field("type", "boolean")
-                .endObject()
-                .startObject("binary_field")
-                .field("type", "binary")
-                .field("doc_values", true) // off by default on binary fields
-                .endObject()
-                .startObject("ip_field")
-                .field("type", "ip")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("_source")
+            .field("enabled", false)
+            .endObject()
+            .startObject("properties")
+            .startObject("text_field")
+            .field("type", "text")
+            .field("fielddata", true)
+            .endObject()
+            .startObject("keyword_field")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("byte_field")
+            .field("type", "byte")
+            .endObject()
+            .startObject("short_field")
+            .field("type", "short")
+            .endObject()
+            .startObject("integer_field")
+            .field("type", "integer")
+            .endObject()
+            .startObject("long_field")
+            .field("type", "long")
+            .endObject()
+            .startObject("float_field")
+            .field("type", "float")
+            .endObject()
+            .startObject("double_field")
+            .field("type", "double")
+            .endObject()
+            .startObject("date_field")
+            .field("type", "date")
+            .endObject()
+            .startObject("boolean_field")
+            .field("type", "boolean")
+            .endObject()
+            .startObject("binary_field")
+            .field("type", "binary")
+            .field("doc_values", true) // off by default on binary fields
+            .endObject()
+            .startObject("ip_field")
+            .field("type", "ip")
+            .endObject()
+            .startObject("flat_object_field")
+            .field("type", "flat_object")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
-        client().admin().indices().preparePutMapping().setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping().setSource(mapping, MediaTypeRegistry.JSON).get();
 
         ZonedDateTime date = ZonedDateTime.of(2012, 3, 22, 0, 0, 0, 0, ZoneOffset.UTC);
         client().prepareIndex("test")
@@ -923,6 +1030,10 @@ public void testDocValueFields() throws Exception {
                     .field("boolean_field", true)
                     .field("binary_field", new byte[] { 42, 100 })
                     .field("ip_field", "::1")
+                    .field("flat_object_field")
+                    .startObject()
+                    .field("foo", "bar")
+                    .endObject()
                     .endObject()
             )
             .get();
@@ -942,7 +1053,8 @@ public void testDocValueFields() throws Exception {
             .addDocValueField("date_field")
             .addDocValueField("boolean_field")
             .addDocValueField("binary_field")
-            .addDocValueField("ip_field");
+            .addDocValueField("ip_field")
+            .addDocValueField("flat_object_field");
         SearchResponse searchResponse = builder.get();
 
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
@@ -963,11 +1075,11 @@ public void testDocValueFields() throws Exception {
                     "text_field",
                     "keyword_field",
                     "binary_field",
-                    "ip_field"
+                    "ip_field",
+                    "flat_object_field"
                 )
             )
         );
-
         assertThat(searchResponse.getHits().getAt(0).getFields().get("byte_field").getValue().toString(), equalTo("1"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("short_field").getValue().toString(), equalTo("2"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("integer_field").getValue(), equalTo((Object) 3L));
@@ -983,6 +1095,7 @@ public void testDocValueFields() throws Exception {
         assertThat(searchResponse.getHits().getAt(0).getFields().get("keyword_field").getValue(), equalTo("foo"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("binary_field").getValue(), equalTo("KmQ"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("ip_field").getValue(), equalTo("::1"));
+        assertThat(searchResponse.getHits().getAt(0).getFields().get("flat_object_field").getValue(), equalTo("flat_object_field.foo"));
 
         builder = client().prepareSearch().setQuery(matchAllQuery()).addDocValueField("*field");
         searchResponse = builder.get();
@@ -1005,7 +1118,8 @@ public void testDocValueFields() throws Exception {
                     "text_field",
                     "keyword_field",
                     "binary_field",
-                    "ip_field"
+                    "ip_field",
+                    "flat_object_field"
                 )
             )
         );
@@ -1025,6 +1139,7 @@ public void testDocValueFields() throws Exception {
         assertThat(searchResponse.getHits().getAt(0).getFields().get("keyword_field").getValue(), equalTo("foo"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("binary_field").getValue(), equalTo("KmQ"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("ip_field").getValue(), equalTo("::1"));
+        assertThat(searchResponse.getHits().getAt(0).getFields().get("flat_object_field").getValue(), equalTo("flat_object_field.foo"));
 
         builder = client().prepareSearch()
             .setQuery(matchAllQuery())
@@ -1039,7 +1154,9 @@ public void testDocValueFields() throws Exception {
             .addDocValueField("date_field", "use_field_mapping")
             .addDocValueField("boolean_field", "use_field_mapping")
             .addDocValueField("binary_field", "use_field_mapping")
-            .addDocValueField("ip_field", "use_field_mapping");
+            .addDocValueField("ip_field", "use_field_mapping")
+            .addDocValueField("flat_object_field", "use_field_mapping");
+        ;
         searchResponse = builder.get();
 
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
@@ -1060,7 +1177,8 @@ public void testDocValueFields() throws Exception {
                     "text_field",
                     "keyword_field",
                     "binary_field",
-                    "ip_field"
+                    "ip_field",
+                    "flat_object_field"
                 )
             )
         );
@@ -1080,6 +1198,7 @@ public void testDocValueFields() throws Exception {
         assertThat(searchResponse.getHits().getAt(0).getFields().get("keyword_field").getValue(), equalTo("foo"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("binary_field").getValue(), equalTo("KmQ"));
         assertThat(searchResponse.getHits().getAt(0).getFields().get("ip_field").getValue(), equalTo("::1"));
+        assertThat(searchResponse.getHits().getAt(0).getFields().get("flat_object_field").getValue(), equalTo("flat_object_field.foo"));
 
         builder = client().prepareSearch()
             .setQuery(matchAllQuery())
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/DecayFunctionScoreIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/DecayFunctionScoreIT.java
index 709a916d98838..6eb528e0bb7d3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/DecayFunctionScoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/DecayFunctionScoreIT.java
@@ -32,19 +32,22 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery.ScoreMode;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;
@@ -53,12 +56,14 @@
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.Locale;
 
@@ -72,6 +77,7 @@
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.exponentialDecayFunction;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.gaussDecayFunction;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.linearDecayFunction;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -85,7 +91,24 @@
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.lessThan;
 
-public class DecayFunctionScoreIT extends OpenSearchIntegTestCase {
+public class DecayFunctionScoreIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public DecayFunctionScoreIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected boolean forbidPrivateIndexSettings() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/ExplainableScriptIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/ExplainableScriptIT.java
index f67b913a75871..c43863a92c283 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/ExplainableScriptIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/ExplainableScriptIT.java
@@ -32,14 +32,18 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Explanation;
+import org.apache.lucene.search.IndexSearcher;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.Functions;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ScriptPlugin;
@@ -52,9 +56,9 @@
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.lookup.SearchLookup;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
 import java.io.IOException;
@@ -72,13 +76,31 @@
 import static org.opensearch.index.query.QueryBuilders.functionScoreQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.scriptFunction;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.hamcrest.Matchers.arrayWithSize;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
 @ClusterScope(scope = Scope.SUITE, supportsDedicatedMasters = false, numDataNodes = 1)
-public class ExplainableScriptIT extends OpenSearchIntegTestCase {
+public class ExplainableScriptIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ExplainableScriptIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public static class ExplainableScriptPlugin extends Plugin implements ScriptPlugin {
         @Override
@@ -93,7 +115,7 @@ public String getType() {
                 public <T> T compile(String scriptName, String scriptSource, ScriptContext<T> context, Map<String, String> params) {
                     assert scriptSource.equals("explainable_script");
                     assert context == ScoreScript.CONTEXT;
-                    ScoreScript.Factory factory = (params1, lookup) -> new ScoreScript.LeafFactory() {
+                    ScoreScript.Factory factory = (params1, lookup, indexSearcher) -> new ScoreScript.LeafFactory() {
                         @Override
                         public boolean needs_score() {
                             return false;
@@ -101,7 +123,7 @@ public boolean needs_score() {
 
                         @Override
                         public ScoreScript newInstance(LeafReaderContext ctx) throws IOException {
-                            return new MyScript(params1, lookup, ctx);
+                            return new MyScript(params1, lookup, indexSearcher, ctx);
                         }
                     };
                     return context.factoryClazz.cast(factory);
@@ -117,8 +139,8 @@ public Set<ScriptContext<?>> getSupportedContexts() {
 
     static class MyScript extends ScoreScript implements ExplainableScoreScript {
 
-        MyScript(Map<String, Object> params, SearchLookup lookup, LeafReaderContext leafContext) {
-            super(params, lookup, leafContext);
+        MyScript(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher, LeafReaderContext leafContext) {
+            super(params, lookup, indexSearcher, leafContext);
         }
 
         @Override
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreFieldValueIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreFieldValueIT.java
index 4e1df591cb245..b09914c4aa764 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreFieldValueIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreFieldValueIT.java
@@ -32,29 +32,54 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.arrayWithSize;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.functionScoreQuery;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.simpleQueryStringQuery;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.fieldValueFactorFunction;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertOrderedSearchHits;
+import static org.hamcrest.Matchers.arrayWithSize;
+import static org.hamcrest.Matchers.containsString;
 
 /**
  * Tests for the {@code field_value_factor} function in a function_score query.
  */
-public class FunctionScoreFieldValueIT extends OpenSearchIntegTestCase {
+public class FunctionScoreFieldValueIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public FunctionScoreFieldValueIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testFieldValueFactor() throws IOException {
         assertAcked(
             prepareCreate("test").setMapping(
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreIT.java
index 3d24933f66d17..88395f25700d2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScoreIT.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder.FilterFunctionBuilder;
@@ -45,11 +49,12 @@
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -63,6 +68,7 @@
 import static org.opensearch.index.query.QueryBuilders.functionScoreQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.scriptFunction;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -72,11 +78,28 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
-public class FunctionScoreIT extends OpenSearchIntegTestCase {
+public class FunctionScoreIT extends ParameterizedOpenSearchIntegTestCase {
 
     static final String TYPE = "type";
     static final String INDEX = "index";
 
+    public FunctionScoreIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(CustomScriptPlugin.class);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScorePluginIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScorePluginIT.java
index a7a14f3b0d889..1df4acac0dcf0 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScorePluginIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/FunctionScorePluginIT.java
@@ -32,13 +32,17 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.Explanation;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.Priority;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.query.functionscore.DecayFunction;
 import org.opensearch.index.query.functionscore.DecayFunctionBuilder;
 import org.opensearch.index.query.functionscore.DecayFunctionParser;
@@ -46,9 +50,9 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.SearchHits;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
 import java.io.IOException;
@@ -62,11 +66,30 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.functionScoreQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.builder.SearchSourceBuilder.searchSource;
 import static org.hamcrest.Matchers.equalTo;
 
 @ClusterScope(scope = Scope.SUITE, supportsDedicatedMasters = false, numDataNodes = 1)
-public class FunctionScorePluginIT extends OpenSearchIntegTestCase {
+public class FunctionScorePluginIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public FunctionScorePluginIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(CustomDistanceScorePlugin.class);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/QueryRescorerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/QueryRescorerIT.java
index c4a41ad5b76e2..de4c85301547c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/QueryRescorerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/QueryRescorerIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.tests.util.English;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -41,8 +43,9 @@
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.Operator;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -52,9 +55,10 @@
 import org.opensearch.search.rescore.QueryRescoreMode;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.search.sort.SortBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Comparator;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
@@ -70,6 +74,7 @@
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.weightFactorFunction;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFourthHit;
@@ -86,7 +91,25 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.notNullValue;
 
-public class QueryRescorerIT extends OpenSearchIntegTestCase {
+public class QueryRescorerIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public QueryRescorerIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testEnforceWindowSize() {
         createIndex("test");
         // this
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/RandomScoreFunctionIT.java b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/RandomScoreFunctionIT.java
index 0701e96b71f38..8f43cefd2d53b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/functionscore/RandomScoreFunctionIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/functionscore/RandomScoreFunctionIT.java
@@ -31,8 +31,12 @@
 
 package org.opensearch.search.functionscore;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;
@@ -43,7 +47,7 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.CoreMatchers;
 
 import java.util.Arrays;
@@ -60,6 +64,7 @@
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.randomFunction;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.scriptFunction;
 import static org.opensearch.script.MockScriptPlugin.NAME;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.Matchers.allOf;
@@ -71,7 +76,24 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.nullValue;
 
-public class RandomScoreFunctionIT extends OpenSearchIntegTestCase {
+public class RandomScoreFunctionIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public RandomScoreFunctionIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -117,7 +139,7 @@ public void testConsistentHitsWithSameSeed() throws Exception {
         for (int o = 0; o < outerIters; o++) {
             final int seed = randomInt();
             String preference = randomRealisticUnicodeOfLengthBetween(1, 10); // at least one char!!
-            // randomPreference should not start with '_' (reserved for known preference types (e.g. _shards)
+            // randomPreference should not start with '_' (reserved for known preference types (e.g. _shards, _primary)
             while (preference.startsWith("_")) {
                 preference = randomRealisticUnicodeOfLengthBetween(1, 10);
             }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoBoundingBoxQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoBoundingBoxQueryIT.java
index 3e63987af20f2..2f48ea0f64e35 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoBoundingBoxQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoBoundingBoxQueryIT.java
@@ -36,8 +36,8 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.GeoValidationMethod;
 import org.opensearch.search.SearchHit;
 import org.opensearch.test.OpenSearchIntegTestCase;
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoDistanceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoDistanceIT.java
index d28410ec170d4..272f07e874fdf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoDistanceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/AbstractGeoDistanceIT.java
@@ -40,8 +40,8 @@
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.query.IdsQueryBuilder;
@@ -66,11 +66,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
-import static org.hamcrest.Matchers.anyOf;
-import static org.hamcrest.Matchers.equalTo;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.equalTo;
 
 /** base class for testing geo_distance queries on geo_ field types */
 abstract class AbstractGeoDistanceIT extends OpenSearchIntegTestCase {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoPointsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoPointsIT.java
index d039e1200a862..083dd829ef5ee 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoPointsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoPointsIT.java
@@ -8,7 +8,7 @@
 
 package org.opensearch.search.geo;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoShapesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoShapesIT.java
index 44f9dd6d01144..1b99d9fc09146 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoShapesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoBoundingBoxQueryGeoShapesIT.java
@@ -8,7 +8,7 @@
 
 package org.opensearch.search.geo;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoPointsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoPointsIT.java
index af19763577666..f171555aed13a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoPointsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoPointsIT.java
@@ -8,8 +8,8 @@
 
 package org.opensearch.search.geo;
 
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.junit.Before;
-import org.opensearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoShapesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoShapesIT.java
index f7e0b7dda4b2c..26702d8313e4b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoShapesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoDistanceQueryGeoShapesIT.java
@@ -8,8 +8,8 @@
 
 package org.opensearch.search.geo;
 
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.junit.Before;
-import org.opensearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoFilterIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoFilterIT.java
index 975cb5f7e3b8c..00524c6e04707 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoFilterIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoFilterIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.geo;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.spatial.prefix.RecursivePrefixTreeStrategy;
@@ -39,7 +41,6 @@
 import org.apache.lucene.spatial.query.SpatialArgs;
 import org.apache.lucene.spatial.query.SpatialOperation;
 import org.apache.lucene.spatial.query.UnsupportedSpatialOperation;
-
 import org.opensearch.Version;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.bulk.BulkItemResponse;
@@ -47,8 +48,6 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.geo.builders.CoordinatesBuilder;
@@ -57,35 +56,40 @@
 import org.opensearch.common.geo.builders.PointBuilder;
 import org.opensearch.common.geo.builders.PolygonBuilder;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.common.util.io.Streams;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
-
 import org.junit.BeforeClass;
-import org.locationtech.spatial4j.context.SpatialContext;
-import org.locationtech.spatial4j.distance.DistanceUtils;
-import org.locationtech.spatial4j.exception.InvalidShapeException;
-import org.locationtech.spatial4j.shape.Shape;
 
 import java.io.ByteArrayOutputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Random;
 import java.util.zip.GZIPInputStream;
 
+import org.locationtech.spatial4j.context.SpatialContext;
+import org.locationtech.spatial4j.distance.DistanceUtils;
+import org.locationtech.spatial4j.exception.InvalidShapeException;
+import org.locationtech.spatial4j.shape.Shape;
+
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.geometry.utils.Geohash.addNeighbors;
 import static org.opensearch.index.query.QueryBuilders.geoBoundingBoxQuery;
 import static org.opensearch.index.query.QueryBuilders.geoDistanceQuery;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasId;
@@ -95,7 +99,24 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
-public class GeoFilterIT extends OpenSearchIntegTestCase {
+public class GeoFilterIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public GeoFilterIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected boolean forbidPrivateIndexSettings() {
@@ -211,17 +232,16 @@ public void testShapeRelations() throws Exception {
         assertTrue("Disjoint relation is not supported", disjointSupport);
         assertTrue("within relation is not supported", withinSupport);
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("area")
-                .field("type", "geo_shape")
-                .field("tree", "geohash")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("area")
+            .field("type", "geo_shape")
+            .field("tree", "geohash")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         CreateIndexRequestBuilder mappingRequest = client().admin().indices().prepareCreate("shapes").setMapping(mapping);
         mappingRequest.get();
@@ -244,7 +264,7 @@ public void testShapeRelations() throws Exception {
             );
         BytesReference data = BytesReference.bytes(jsonBuilder().startObject().field("area", polygon).endObject());
 
-        client().prepareIndex("shapes").setId("1").setSource(data, XContentType.JSON).get();
+        client().prepareIndex("shapes").setId("1").setSource(data, MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         // Point in polygon
@@ -307,7 +327,7 @@ public void testShapeRelations() throws Exception {
         );
 
         data = BytesReference.bytes(jsonBuilder().startObject().field("area", inverse).endObject());
-        client().prepareIndex("shapes").setId("2").setSource(data, XContentType.JSON).get();
+        client().prepareIndex("shapes").setId("2").setSource(data, MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         // re-check point on polygon hole
@@ -346,7 +366,7 @@ public void testShapeRelations() throws Exception {
         );
 
         data = BytesReference.bytes(jsonBuilder().startObject().field("area", builder).endObject());
-        client().prepareIndex("shapes").setId("1").setSource(data, XContentType.JSON).get();
+        client().prepareIndex("shapes").setId("1").setSource(data, MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         // Create a polygon crossing longitude 180 with hole.
@@ -359,7 +379,7 @@ public void testShapeRelations() throws Exception {
         );
 
         data = BytesReference.bytes(jsonBuilder().startObject().field("area", builder).endObject());
-        client().prepareIndex("shapes").setId("1").setSource(data, XContentType.JSON).get();
+        client().prepareIndex("shapes").setId("1").setSource(data, MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         result = client().prepareSearch()
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoPolygonIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoPolygonIT.java
index d0b017732b270..85cb087585d31 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoPolygonIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoPolygonIT.java
@@ -32,28 +32,52 @@
 
 package org.opensearch.search.geo;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.Version;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.SearchHit;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.boolQuery;
 import static org.opensearch.index.query.QueryBuilders.geoPolygonQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class GeoPolygonIT extends OpenSearchIntegTestCase {
+public class GeoPolygonIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public GeoPolygonIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected boolean forbidPrivateIndexSettings() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoShapeIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoShapeIntegrationIT.java
index 89eb6038d8110..1f9b6ae434f75 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoShapeIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/GeoShapeIntegrationIT.java
@@ -32,31 +32,53 @@
 
 package org.opensearch.search.geo;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.builders.PointBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.GeoShapeFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.index.query.QueryBuilders.geoShapeQuery;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class GeoShapeIntegrationIT extends OpenSearchIntegTestCase {
+public class GeoShapeIntegrationIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public GeoShapeIntegrationIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
@@ -73,32 +95,30 @@ protected Settings nodeSettings(int nodeOrdinal) {
      */
     public void testOrientationPersistence() throws Exception {
         String idxName = "orientation";
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "geo_shape")
-                .field("orientation", "left")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "geo_shape")
+            .field("orientation", "left")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         // create index
         assertAcked(prepareCreate(idxName).setMapping(mapping));
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "geo_shape")
-                .field("orientation", "right")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "geo_shape")
+            .field("orientation", "right")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertAcked(prepareCreate(idxName + "2").setMapping(mapping));
         ensureGreen(idxName, idxName + "2");
@@ -140,44 +160,43 @@ public void testIgnoreMalformed() throws Exception {
         ensureGreen();
 
         // test self crossing ccw poly not crossing dateline
-        String polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         indexRandom(true, client().prepareIndex("test").setId("0").setSource("shape", polygonGeoJson));
         SearchResponse searchResponse = client().prepareSearch("test").setQuery(matchAllQuery()).get();
@@ -200,7 +219,7 @@ public void testMappingUpdate() throws Exception {
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> client().admin().indices().preparePutMapping("test").setSource(update, XContentType.JSON).get()
+            () -> client().admin().indices().preparePutMapping("test").setSource(update, MediaTypeRegistry.JSON).get()
         );
         assertThat(e.getMessage(), containsString("using [BKD] strategy cannot be merged with"));
     }
@@ -231,7 +250,7 @@ public void testIndexShapeRouting() throws Exception {
             + "    }\n"
             + "}";
 
-        indexRandom(true, client().prepareIndex("test").setId("0").setSource(source, XContentType.JSON).setRouting("ABC"));
+        indexRandom(true, client().prepareIndex("test").setId("0").setSource(source, MediaTypeRegistry.JSON).setRouting("ABC"));
 
         SearchResponse searchResponse = client().prepareSearch("test")
             .setQuery(geoShapeQuery("shape", "0").indexedShapeIndex("test").indexedShapeRouting("ABC"))
@@ -267,8 +286,8 @@ public void testIndexPolygonDateLine() throws Exception {
 
         String source = "{\n" + "    \"shape\" : \"POLYGON((179 0, -179 0, -179 2, 179 2, 179 0))\"" + "}";
 
-        indexRandom(true, client().prepareIndex("quad").setId("0").setSource(source, XContentType.JSON));
-        indexRandom(true, client().prepareIndex("vector").setId("0").setSource(source, XContentType.JSON));
+        indexRandom(true, client().prepareIndex("quad").setId("0").setSource(source, MediaTypeRegistry.JSON));
+        indexRandom(true, client().prepareIndex("vector").setId("0").setSource(source, MediaTypeRegistry.JSON));
 
         try {
             ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/geo/LegacyGeoShapeIntegrationIT.java b/server/src/internalClusterTest/java/org/opensearch/search/geo/LegacyGeoShapeIntegrationIT.java
index 61af97d46e7f3..d21d6036c9673 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/geo/LegacyGeoShapeIntegrationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/geo/LegacyGeoShapeIntegrationIT.java
@@ -32,67 +32,87 @@
 
 package org.opensearch.search.geo;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.geometry.Circle;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.LegacyGeoShapeFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.index.query.QueryBuilders.geoShapeQuery;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class LegacyGeoShapeIntegrationIT extends OpenSearchIntegTestCase {
+public class LegacyGeoShapeIntegrationIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public LegacyGeoShapeIntegrationIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     /**
      * Test that orientation parameter correctly persists across cluster restart
      */
     public void testOrientationPersistence() throws Exception {
         String idxName = "orientation";
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "geo_shape")
-                .field("tree", "quadtree")
-                .field("orientation", "left")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "geo_shape")
+            .field("tree", "quadtree")
+            .field("orientation", "left")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         // create index
         assertAcked(prepareCreate(idxName).setMapping(mapping));
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "geo_shape")
-                .field("tree", "quadtree")
-                .field("orientation", "right")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "geo_shape")
+            .field("tree", "quadtree")
+            .field("orientation", "right")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertAcked(prepareCreate(idxName + "2").setMapping(mapping));
         ensureGreen(idxName, idxName + "2");
@@ -136,44 +156,43 @@ public void testIgnoreMalformed() throws Exception {
         ensureGreen();
 
         // test self crossing ccw poly not crossing dateline
-        String polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         indexRandom(true, client().prepareIndex("test").setId("0").setSource("shape", polygonGeoJson));
         SearchResponse searchResponse = client().prepareSearch("test").setQuery(matchAllQuery()).get();
@@ -207,7 +226,7 @@ public void testIndexShapeRouting() throws Exception {
             + "    }\n"
             + "}";
 
-        indexRandom(true, client().prepareIndex("test").setId("0").setSource(source, XContentType.JSON).setRouting("ABC"));
+        indexRandom(true, client().prepareIndex("test").setId("0").setSource(source, MediaTypeRegistry.JSON).setRouting("ABC"));
 
         SearchResponse searchResponse = client().prepareSearch("test")
             .setQuery(geoShapeQuery("shape", "0").indexedShapeIndex("test").indexedShapeRouting("ABC"))
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/morelikethis/MoreLikeThisIT.java b/server/src/internalClusterTest/java/org/opensearch/search/morelikethis/MoreLikeThisIT.java
index b3253b036bda6..4197641e33f3b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/morelikethis/MoreLikeThisIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/morelikethis/MoreLikeThisIT.java
@@ -32,26 +32,29 @@
 
 package org.opensearch.search.morelikethis;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.health.ClusterHealthStatus;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MoreLikeThisQueryBuilder;
 import org.opensearch.index.query.MoreLikeThisQueryBuilder.Item;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -64,6 +67,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.moreLikeThisQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -75,7 +79,24 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.notNullValue;
 
-public class MoreLikeThisIT extends OpenSearchIntegTestCase {
+public class MoreLikeThisIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MoreLikeThisIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -270,7 +291,7 @@ public void testMoreLikeThisWithAliasesInLikeDocuments() throws Exception {
         String indexName = "foo";
         String aliasName = "foo_name";
 
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject().toString();
         client().admin().indices().prepareCreate(indexName).setMapping(mapping).get();
         client().admin().indices().prepareAliases().addAlias(indexName, aliasName).get();
 
@@ -292,7 +313,7 @@ public void testMoreLikeThisWithAliasesInLikeDocuments() throws Exception {
     }
 
     public void testMoreLikeThisIssue2197() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject().toString();
         client().admin().indices().prepareCreate("foo").setMapping(mapping).get();
         client().prepareIndex("foo")
             .setId("1")
@@ -313,7 +334,7 @@ public void testMoreLikeThisIssue2197() throws Exception {
 
     // Issue #2489
     public void testMoreLikeWithCustomRouting() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject().toString();
         client().admin().indices().prepareCreate("foo").setMapping(mapping).get();
         ensureGreen();
 
@@ -333,7 +354,7 @@ public void testMoreLikeWithCustomRouting() throws Exception {
 
     // Issue #3039
     public void testMoreLikeThisIssueRoutingNotSerialized() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("properties").endObject().endObject().toString();
         assertAcked(
             prepareCreate("foo", 2, Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 2).put(SETTING_NUMBER_OF_REPLICAS, 0)).setMapping(
                 mapping
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/msearch/MultiSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/msearch/MultiSearchIT.java
index 8226663abf49e..bc1d2833ecbbf 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/msearch/MultiSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/msearch/MultiSearchIT.java
@@ -32,19 +32,44 @@
 
 package org.opensearch.search.msearch;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchResponse;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasId;
 import static org.hamcrest.Matchers.equalTo;
 
-public class MultiSearchIT extends OpenSearchIntegTestCase {
+public class MultiSearchIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MultiSearchIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testSimpleMultiSearch() {
         createIndex("test");
@@ -73,7 +98,7 @@ public void testSimpleMultiSearchMoreRequests() {
         createIndex("test");
         int numDocs = randomIntBetween(0, 16);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test").setId(Integer.toString(i)).setSource("{}", MediaTypeRegistry.JSON).get();
         }
         refresh();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/nested/SimpleNestedIT.java b/server/src/internalClusterTest/java/org/opensearch/search/nested/SimpleNestedIT.java
index d2d23cd47fc01..83dec7b27a897 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/nested/SimpleNestedIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/nested/SimpleNestedIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.nested;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.action.DocWriteResponse;
@@ -45,15 +47,19 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.sort.NestedSortBuilder;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortMode;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
@@ -61,17 +67,35 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.nestedQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
-
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.startsWith;
 
-public class SimpleNestedIT extends OpenSearchIntegTestCase {
+public class SimpleNestedIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SimpleNestedIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testSimpleNested() throws Exception {
         assertAcked(prepareCreate("test").setMapping("nested1", "type=nested"));
         ensureGreen();
@@ -783,7 +807,7 @@ public void testNestedSortWithMultiLevelFiltering() throws Exception {
                     + "    }\n"
                     + "  ]\n"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
@@ -835,7 +859,7 @@ public void testNestedSortWithMultiLevelFiltering() throws Exception {
                     + "    }\n"
                     + "  ]\n"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
         refresh();
@@ -987,7 +1011,7 @@ public void testLeakingSortValues() throws Exception {
                     + "    }\n"
                     + " ]\n"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
@@ -1006,7 +1030,7 @@ public void testLeakingSortValues() throws Exception {
                     + "    } \n"
                     + "  ]\n"
                     + "}",
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .get();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/pit/DeletePitMultiNodeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/pit/DeletePitMultiNodeIT.java
new file mode 100644
index 0000000000000..43b7179a335f8
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/pit/DeletePitMultiNodeIT.java
@@ -0,0 +1,368 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pit;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeletePitInfo;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.SearchPhaseExecutionException;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.ShardSearchFailure;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.search.SearchContextMissingException;
+import org.opensearch.search.builder.PointInTimeBuilder;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
+import static org.hamcrest.Matchers.blankOrNullString;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.not;
+
+/**
+ * Multi node integration tests for delete PIT use cases
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, numDataNodes = 2)
+public class DeletePitMultiNodeIT extends OpenSearchIntegTestCase {
+
+    @Before
+    public void setupIndex() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 5).put("index.number_of_replicas", 1).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).execute().get();
+        ensureGreen();
+    }
+
+    @After
+    public void clearIndex() {
+        client().admin().indices().prepareDelete("index").get();
+    }
+
+    private CreatePitResponse createPitOnIndex(String index) throws ExecutionException, InterruptedException {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { index });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        return execute.get();
+    }
+
+    public void testDeletePit() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        execute = client().execute(CreatePitAction.INSTANCE, request);
+        pitResponse = execute.get();
+        pitIds.add(pitResponse.getId());
+        validatePitStats("index", 10, 0);
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        ActionFuture<DeletePitResponse> deleteExecute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = deleteExecute.get();
+        assertEquals(2, deletePITResponse.getDeletePitResults().size());
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        validatePitStats("index", 0, 10);
+        /**
+         * Checking deleting the same PIT id again results in succeeded
+         */
+        deleteExecute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        deletePITResponse = deleteExecute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+    }
+
+    public void testDeletePitWithValidAndDeletedIds() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        validatePitStats("index", 5, 0);
+
+        /**
+         * Delete Pit #1
+         */
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        ActionFuture<DeletePitResponse> deleteExecute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = deleteExecute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        validatePitStats("index", 0, 5);
+        execute = client().execute(CreatePitAction.INSTANCE, request);
+        pitResponse = execute.get();
+        pitIds.add(pitResponse.getId());
+        validatePitStats("index", 5, 5);
+        /**
+         * Delete PIT with both Ids #1 (which is deleted) and #2 (which is present)
+         */
+        deletePITRequest = new DeletePitRequest(pitIds);
+        deleteExecute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        deletePITResponse = deleteExecute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        validatePitStats("index", 0, 10);
+    }
+
+    public void testDeletePitWithValidAndInvalidIds() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        pitIds.add("nondecodableid");
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        ActionFuture<DeletePitResponse> deleteExecute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        Exception e = assertThrows(ExecutionException.class, () -> deleteExecute.get());
+        assertThat(e.getMessage(), containsString("invalid id"));
+    }
+
+    public void testDeleteAllPits() throws Exception {
+        createPitOnIndex("index");
+        createIndex("index1", Settings.builder().put("index.number_of_shards", 5).put("index.number_of_replicas", 1).build());
+        client().prepareIndex("index1").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).execute().get();
+        ensureGreen();
+        createPitOnIndex("index1");
+        validatePitStats("index", 5, 0);
+        validatePitStats("index1", 5, 0);
+        DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+
+        /**
+         * When we invoke delete again, returns success after clearing the remaining readers. Asserting reader context
+         * not found exceptions don't result in failures ( as deletion in one node is successful )
+         */
+        ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = execute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertThat(deletePitInfo.getPitId(), not(blankOrNullString()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        validatePitStats("index", 0, 5);
+        validatePitStats("index1", 0, 5);
+        client().admin().indices().prepareDelete("index1").get();
+    }
+
+    public void testDeletePitWhileNodeDrop() throws Exception {
+        CreatePitResponse pitResponse = createPitOnIndex("index");
+        createIndex("index1", Settings.builder().put("index.number_of_shards", 5).put("index.number_of_replicas", 1).build());
+        client().prepareIndex("index1").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).execute().get();
+        ensureGreen();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        CreatePitResponse pitResponse1 = createPitOnIndex("index1");
+        pitIds.add(pitResponse1.getId());
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+                try {
+                    DeletePitResponse deletePITResponse = execute.get();
+                    for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+                        assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+                    }
+                } catch (Exception e) {
+                    throw new AssertionError(e);
+                }
+                return super.onNodeStopped(nodeName);
+            }
+        });
+
+        ensureGreen();
+        /**
+         * When we invoke delete again, returns success after clearing the remaining readers. Asserting reader context
+         * not found exceptions don't result in failures ( as deletion in one node is successful )
+         */
+        ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = execute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        client().admin().indices().prepareDelete("index1").get();
+    }
+
+    public void testDeleteAllPitsWhileNodeDrop() throws Exception {
+        createIndex("index1", Settings.builder().put("index.number_of_shards", 5).put("index.number_of_replicas", 1).build());
+        client().prepareIndex("index1").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).execute().get();
+        createPitOnIndex("index1");
+        ensureGreen();
+        DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+                try {
+                    DeletePitResponse deletePITResponse = execute.get();
+                    for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+                        assertThat(deletePitInfo.getPitId(), not(blankOrNullString()));
+                    }
+                } catch (Exception e) {
+                    assertTrue(e.getMessage().contains("Node not connected"));
+                }
+                return super.onNodeStopped(nodeName);
+            }
+        });
+        ensureGreen();
+        /**
+         * When we invoke delete again, returns success as all readers are cleared. (Delete all on node which is Up and
+         * once the node restarts, all active contexts are cleared in the node )
+         */
+        ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = execute.get();
+        assertEquals(0, deletePITResponse.getDeletePitResults().size());
+        client().admin().indices().prepareDelete("index1").get();
+    }
+
+    public void testDeleteWhileSearch() throws Exception {
+        CreatePitResponse pitResponse = createPitOnIndex("index");
+        ensureGreen();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        Thread[] threads = new Thread[5];
+        CountDownLatch latch = new CountDownLatch(threads.length);
+        final AtomicBoolean deleted = new AtomicBoolean(false);
+
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new Thread(() -> {
+                latch.countDown();
+                try {
+                    latch.await();
+                    for (int j = 0; j < 30; j++) {
+                        SearchResponse searchResponse = client().prepareSearch()
+                            .setSize(2)
+                            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                            .execute()
+                            .get();
+                        if (searchResponse.getFailedShards() != 0) {
+                            verifySearchContextMissingException(searchResponse.getShardFailures());
+                        }
+                    }
+                } catch (Exception e) {
+                    /**
+                     * assert for exception once delete pit goes through. throw error in case of any exeption before that.
+                     */
+                    if (deleted.get() == true) {
+                        Throwable t = ExceptionsHelper.unwrapCause(e.getCause());
+                        assertTrue(e.toString(), t instanceof SearchPhaseExecutionException);
+                        verifySearchContextMissingException(((SearchPhaseExecutionException) t).shardFailures());
+                        return;
+                    }
+                    throw new AssertionError(e);
+                }
+            });
+            threads[i].setName("opensearch[node_s_0][search]");
+            threads[i].start();
+        }
+        deleted.set(true);
+        ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = execute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertTrue(pitIds.contains(deletePitInfo.getPitId()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+
+        for (Thread thread : threads) {
+            thread.join();
+        }
+    }
+
+    private void verifySearchContextMissingException(ShardSearchFailure[] failures) {
+        for (ShardSearchFailure failure : failures) {
+            Throwable cause = ExceptionsHelper.unwrapCause(failure.getCause());
+            assertTrue(failure.toString(), cause instanceof SearchContextMissingException);
+        }
+    }
+
+    public void testtConcurrentDeletes() throws InterruptedException, ExecutionException {
+        CreatePitResponse pitResponse = createPitOnIndex("index");
+        ensureGreen();
+        int concurrentRuns = randomIntBetween(20, 50);
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitResponse.getId());
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        AtomicInteger numDeleteAcknowledged = new AtomicInteger();
+        TestThreadPool testThreadPool = null;
+        try {
+            testThreadPool = new TestThreadPool(DeletePitMultiNodeIT.class.getName());
+            List<Runnable> operationThreads = new ArrayList<>();
+            CountDownLatch countDownLatch = new CountDownLatch(concurrentRuns);
+            for (int i = 0; i < concurrentRuns; i++) {
+                Runnable thread = () -> {
+                    logger.info("Triggering pit delete --->");
+                    LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<DeletePitResponse>() {
+                        @Override
+                        public void onResponse(DeletePitResponse deletePitResponse) {
+                            if (deletePitResponse.getDeletePitResults().get(0).isSuccessful()) {
+                                numDeleteAcknowledged.incrementAndGet();
+                            }
+                        }
+
+                        @Override
+                        public void onFailure(Exception e) {}
+                    }, countDownLatch);
+                    client().execute(DeletePitAction.INSTANCE, deletePITRequest, listener);
+                };
+                operationThreads.add(thread);
+            }
+            TestThreadPool finalTestThreadPool = testThreadPool;
+            operationThreads.forEach(runnable -> finalTestThreadPool.executor("generic").execute(runnable));
+            countDownLatch.await();
+            assertEquals(concurrentRuns, numDeleteAcknowledged.get());
+        } finally {
+            ThreadPool.terminate(testThreadPool, 500, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    public void validatePitStats(String index, long expectedPitCurrent, long expectedPitCount) throws ExecutionException,
+        InterruptedException {
+        IndicesStatsRequest indicesStatsRequest = new IndicesStatsRequest();
+        indicesStatsRequest.indices(index);
+        indicesStatsRequest.all();
+        IndicesStatsResponse indicesStatsResponse = client().admin().indices().stats(indicesStatsRequest).get();
+        long pitCurrent = indicesStatsResponse.getIndex(index).getTotal().search.getTotal().getPitCurrent();
+        long pitCount = indicesStatsResponse.getIndex(index).getTotal().search.getTotal().getPitCount();
+        assertEquals(expectedPitCurrent, pitCurrent);
+        assertEquals(expectedPitCount, pitCount);
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/pit/PitMultiNodeIT.java b/server/src/internalClusterTest/java/org/opensearch/search/pit/PitMultiNodeIT.java
new file mode 100644
index 0000000000000..413e5eafe56c7
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/pit/PitMultiNodeIT.java
@@ -0,0 +1,494 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pit;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.GetAllPitNodesRequest;
+import org.opensearch.action.search.GetAllPitNodesResponse;
+import org.opensearch.action.search.GetAllPitsAction;
+import org.opensearch.action.search.PitTestsUtil;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.search.builder.PointInTimeBuilder;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
+
+import static org.opensearch.action.search.PitTestsUtil.assertSegments;
+import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.containsString;
+
+/**
+ * Multi node integration tests for PIT creation and search operation with PIT ID.
+ */
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE, numDataNodes = 2)
+public class PitMultiNodeIT extends ParameterizedOpenSearchIntegTestCase {
+    public PitMultiNodeIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    @Before
+    public void setupIndex() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).execute().get();
+        ensureGreen();
+    }
+
+    @After
+    public void clearIndex() {
+        client().admin().indices().prepareDelete("index").get();
+    }
+
+    public void testPit() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        SearchResponse searchResponse = client().prepareSearch("index")
+            .setSize(2)
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+            .get();
+        assertEquals(2, searchResponse.getSuccessfulShards());
+        assertEquals(2, searchResponse.getTotalShards());
+        validatePitStats("index", 2, 2);
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, client(), pitResponse.getId());
+    }
+
+    public void testCreatePitWhileNodeDropWithAllowPartialCreationFalse() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), false);
+        request.setIndices(new String[] { "index" });
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+                ExecutionException ex = expectThrows(ExecutionException.class, execute::get);
+                assertTrue(ex.getMessage().contains("Failed to execute phase [create_pit]"));
+                validatePitStats("index", 0, 0);
+                return super.onNodeStopped(nodeName);
+            }
+        });
+    }
+
+    public void testCreatePitWhileNodeDropWithAllowPartialCreationTrue() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+                CreatePitResponse pitResponse = execute.get();
+                PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+                assertSegments(false, "index", 1, client(), pitResponse.getId());
+                assertEquals(1, pitResponse.getSuccessfulShards());
+                assertEquals(2, pitResponse.getTotalShards());
+                SearchResponse searchResponse = client().prepareSearch("index")
+                    .setSize(2)
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                    .get();
+                assertEquals(1, searchResponse.getSuccessfulShards());
+                assertEquals(1, searchResponse.getTotalShards());
+                validatePitStats("index", 1, 1);
+                return super.onNodeStopped(nodeName);
+            }
+        });
+    }
+
+    public void testPitSearchWithNodeDrop() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                SearchResponse searchResponse = client().prepareSearch()
+                    .setSize(2)
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                    .get();
+                assertEquals(1, searchResponse.getSuccessfulShards());
+                assertEquals(1, searchResponse.getFailedShards());
+                assertEquals(0, searchResponse.getSkippedShards());
+                assertEquals(2, searchResponse.getTotalShards());
+                validatePitStats("index", 1, 1);
+                PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+                return super.onNodeStopped(nodeName);
+            }
+        });
+    }
+
+    public void testPitSearchWithNodeDropWithPartialSearchResultsFalse() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<SearchResponse> execute = client().prepareSearch()
+                    .setSize(2)
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                    .setAllowPartialSearchResults(false)
+                    .execute();
+                ExecutionException ex = expectThrows(ExecutionException.class, execute::get);
+                assertTrue(ex.getMessage().contains("Partial shards failure"));
+                return super.onNodeStopped(nodeName);
+            }
+        });
+    }
+
+    public void testPitInvalidDefaultKeepAlive() {
+        IllegalArgumentException exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("point_in_time.max_keep_alive", "1m").put("search.default_keep_alive", "2m"))
+                .get()
+        );
+        assertThat(exc.getMessage(), containsString("was (2m > 1m)"));
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("search.default_keep_alive", "5m").put("point_in_time.max_keep_alive", "5m"))
+                .get()
+        );
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("search.default_keep_alive", "2m"))
+                .get()
+        );
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("point_in_time.max_keep_alive", "2m"))
+                .get()
+        );
+        exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("search.default_keep_alive", "3m"))
+                .get()
+        );
+        assertThat(exc.getMessage(), containsString("was (3m > 2m)"));
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("search.default_keep_alive", "1m"))
+                .get()
+        );
+        exc = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put("point_in_time.max_keep_alive", "30s"))
+                .get()
+        );
+        assertThat(exc.getMessage(), containsString("was (1m > 30s)"));
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().putNull("*"))
+                .setTransientSettings(Settings.builder().putNull("*"))
+        );
+    }
+
+    public void testConcurrentCreates() throws InterruptedException {
+        CreatePitRequest createPitRequest = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        createPitRequest.setIndices(new String[] { "index" });
+
+        int concurrentRuns = randomIntBetween(20, 50);
+        AtomicInteger numSuccess = new AtomicInteger();
+        TestThreadPool testThreadPool = null;
+        try {
+            testThreadPool = new TestThreadPool(PitMultiNodeIT.class.getName());
+            List<Runnable> operationThreads = new ArrayList<>();
+            CountDownLatch countDownLatch = new CountDownLatch(concurrentRuns);
+            Set<String> createSet = new HashSet<>();
+            for (int i = 0; i < concurrentRuns; i++) {
+                Runnable thread = () -> {
+                    logger.info("Triggering pit create --->");
+                    LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                        @Override
+                        public void onResponse(CreatePitResponse createPitResponse) {
+                            if (createSet.add(createPitResponse.getId())) {
+                                numSuccess.incrementAndGet();
+                            }
+                        }
+
+                        @Override
+                        public void onFailure(Exception e) {}
+                    }, countDownLatch);
+                    client().execute(CreatePitAction.INSTANCE, createPitRequest, listener);
+                };
+                operationThreads.add(thread);
+            }
+            TestThreadPool finalTestThreadPool = testThreadPool;
+            operationThreads.forEach(runnable -> finalTestThreadPool.executor("generic").execute(runnable));
+            countDownLatch.await();
+            assertEquals(concurrentRuns, numSuccess.get());
+        } finally {
+            ThreadPool.terminate(testThreadPool, 500, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    public void testConcurrentCreatesWithDeletes() throws InterruptedException, ExecutionException {
+        CreatePitRequest createPitRequest = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        createPitRequest.setIndices(new String[] { "index" });
+        List<String> pitIds = new ArrayList<>();
+        String id = client().execute(CreatePitAction.INSTANCE, createPitRequest).get().getId();
+        pitIds.add(id);
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        Set<String> createSet = new HashSet<>();
+        AtomicInteger numSuccess = new AtomicInteger();
+        TestThreadPool testThreadPool = null;
+        try {
+            testThreadPool = new TestThreadPool(PitMultiNodeIT.class.getName());
+            int concurrentRuns = randomIntBetween(20, 50);
+
+            List<Runnable> operationThreads = new ArrayList<>();
+            CountDownLatch countDownLatch = new CountDownLatch(concurrentRuns);
+            long randomDeleteThread = randomLongBetween(0, concurrentRuns - 1);
+            for (int i = 0; i < concurrentRuns; i++) {
+                int currentThreadIteration = i;
+                Runnable thread = () -> {
+                    if (currentThreadIteration == randomDeleteThread) {
+                        LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                            @Override
+                            public void onResponse(CreatePitResponse createPitResponse) {
+                                if (createSet.add(createPitResponse.getId())) {
+                                    numSuccess.incrementAndGet();
+                                }
+                            }
+
+                            @Override
+                            public void onFailure(Exception e) {}
+                        }, countDownLatch);
+                        client().execute(CreatePitAction.INSTANCE, createPitRequest, listener);
+                    } else {
+                        LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<DeletePitResponse>() {
+                            @Override
+                            public void onResponse(DeletePitResponse deletePitResponse) {
+                                if (deletePitResponse.getDeletePitResults().get(0).isSuccessful()) {
+                                    numSuccess.incrementAndGet();
+                                }
+                            }
+
+                            @Override
+                            public void onFailure(Exception e) {}
+                        }, countDownLatch);
+                        client().execute(DeletePitAction.INSTANCE, deletePITRequest, listener);
+                    }
+                };
+                operationThreads.add(thread);
+            }
+            TestThreadPool finalTestThreadPool = testThreadPool;
+            operationThreads.forEach(runnable -> finalTestThreadPool.executor("generic").execute(runnable));
+            countDownLatch.await();
+            assertEquals(concurrentRuns, numSuccess.get());
+
+        } finally {
+            ThreadPool.terminate(testThreadPool, 500, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    public void validatePitStats(String index, long expectedPitCurrent, long expectedOpenContexts) throws ExecutionException,
+        InterruptedException {
+        IndicesStatsRequest indicesStatsRequest = new IndicesStatsRequest();
+        indicesStatsRequest.indices("index");
+        indicesStatsRequest.all();
+        IndicesStatsResponse indicesStatsResponse = client().admin().indices().stats(indicesStatsRequest).get();
+        long pitCurrent = indicesStatsResponse.getIndex(index).getTotal().search.getTotal().getPitCurrent();
+        long openContexts = indicesStatsResponse.getIndex(index).getTotal().search.getOpenContexts();
+        assertEquals(expectedPitCurrent, pitCurrent);
+        assertEquals(expectedOpenContexts, openContexts);
+    }
+
+    public void testGetAllPits() throws Exception {
+        client().admin().indices().prepareCreate("index1").get();
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index", "index1" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        CreatePitResponse pitResponse1 = client().execute(CreatePitAction.INSTANCE, request).get();
+        CreatePitResponse pitResponse2 = client().execute(CreatePitAction.INSTANCE, request).get();
+        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
+        clusterStateRequest.local(false);
+        clusterStateRequest.clear().nodes(true).routingTable(true).indices("*");
+        ClusterStateResponse clusterStateResponse = client().admin().cluster().state(clusterStateRequest).get();
+        final List<DiscoveryNode> nodes = new LinkedList<>();
+        for (final DiscoveryNode node : clusterStateResponse.getState().nodes().getDataNodes().values()) {
+            nodes.add(node);
+        }
+        DiscoveryNode[] disNodesArr = new DiscoveryNode[nodes.size()];
+        nodes.toArray(disNodesArr);
+        GetAllPitNodesRequest getAllPITNodesRequest = new GetAllPitNodesRequest(disNodesArr);
+        ActionFuture<GetAllPitNodesResponse> execute1 = client().execute(GetAllPitsAction.INSTANCE, getAllPITNodesRequest);
+        GetAllPitNodesResponse getPitResponse = execute1.get();
+        assertEquals(3, getPitResponse.getPitInfos().size());
+        List<String> resultPitIds = getPitResponse.getPitInfos().stream().map(p -> p.getPitId()).collect(Collectors.toList());
+        // asserting that we get all unique PIT IDs
+        Assert.assertTrue(resultPitIds.contains(pitResponse.getId()));
+        Assert.assertTrue(resultPitIds.contains(pitResponse1.getId()));
+        Assert.assertTrue(resultPitIds.contains(pitResponse2.getId()));
+        client().admin().indices().prepareDelete("index1").get();
+    }
+
+    public void testGetAllPitsDuringNodeDrop() throws Exception {
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        GetAllPitNodesRequest getAllPITNodesRequest = new GetAllPitNodesRequest(getDiscoveryNodes());
+        internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
+            @Override
+            public Settings onNodeStopped(String nodeName) throws Exception {
+                ActionFuture<GetAllPitNodesResponse> execute1 = client().execute(GetAllPitsAction.INSTANCE, getAllPITNodesRequest);
+                GetAllPitNodesResponse getPitResponse = execute1.get();
+                // we still get a pit id from the data node which is up
+                assertEquals(1, getPitResponse.getPitInfos().size());
+                // failure for node drop
+                assertEquals(1, getPitResponse.failures().size());
+                assertTrue(getPitResponse.failures().get(0).getMessage().contains("Failed node"));
+                return super.onNodeStopped(nodeName);
+            }
+        });
+    }
+
+    private DiscoveryNode[] getDiscoveryNodes() throws ExecutionException, InterruptedException {
+        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
+        clusterStateRequest.local(false);
+        clusterStateRequest.clear().nodes(true).routingTable(true).indices("*");
+        ClusterStateResponse clusterStateResponse = client().admin().cluster().state(clusterStateRequest).get();
+        final List<DiscoveryNode> nodes = new LinkedList<>(clusterStateResponse.getState().nodes().getDataNodes().values());
+        DiscoveryNode[] disNodesArr = new DiscoveryNode[nodes.size()];
+        nodes.toArray(disNodesArr);
+        return disNodesArr;
+    }
+
+    public void testConcurrentGetWithDeletes() throws InterruptedException, ExecutionException {
+        CreatePitRequest createPitRequest = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        createPitRequest.setIndices(new String[] { "index" });
+        List<String> pitIds = new ArrayList<>();
+        String id = client().execute(CreatePitAction.INSTANCE, createPitRequest).get().getId();
+        pitIds.add(id);
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds);
+        GetAllPitNodesRequest getAllPITNodesRequest = new GetAllPitNodesRequest(getDiscoveryNodes());
+        AtomicInteger numSuccess = new AtomicInteger();
+        TestThreadPool testThreadPool = null;
+        try {
+            testThreadPool = new TestThreadPool(PitMultiNodeIT.class.getName());
+            int concurrentRuns = randomIntBetween(20, 50);
+
+            List<Runnable> operationThreads = new ArrayList<>();
+            CountDownLatch countDownLatch = new CountDownLatch(concurrentRuns);
+            long randomDeleteThread = randomLongBetween(0, concurrentRuns - 1);
+            for (int i = 0; i < concurrentRuns; i++) {
+                int currentThreadIteration = i;
+                Runnable thread = () -> {
+                    if (currentThreadIteration == randomDeleteThread) {
+                        LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<GetAllPitNodesResponse>() {
+                            @Override
+                            public void onResponse(GetAllPitNodesResponse getAllPitNodesResponse) {
+                                if (getAllPitNodesResponse.failures().isEmpty()) {
+                                    numSuccess.incrementAndGet();
+                                }
+                            }
+
+                            @Override
+                            public void onFailure(Exception e) {}
+                        }, countDownLatch);
+                        client().execute(GetAllPitsAction.INSTANCE, getAllPITNodesRequest, listener);
+                    } else {
+                        LatchedActionListener listener = new LatchedActionListener<>(new ActionListener<DeletePitResponse>() {
+                            @Override
+                            public void onResponse(DeletePitResponse deletePitResponse) {
+                                if (deletePitResponse.getDeletePitResults().get(0).isSuccessful()) {
+                                    numSuccess.incrementAndGet();
+                                }
+                            }
+
+                            @Override
+                            public void onFailure(Exception e) {}
+                        }, countDownLatch);
+                        client().execute(DeletePitAction.INSTANCE, deletePITRequest, listener);
+                    }
+                };
+                operationThreads.add(thread);
+            }
+            TestThreadPool finalTestThreadPool = testThreadPool;
+            operationThreads.forEach(runnable -> finalTestThreadPool.executor("generic").execute(runnable));
+            countDownLatch.await();
+            assertEquals(concurrentRuns, numSuccess.get());
+
+        } finally {
+            ThreadPool.terminate(testThreadPool, 500, TimeUnit.MILLISECONDS);
+        }
+    }
+
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/preference/SearchPreferenceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/preference/SearchPreferenceIT.java
index c69555d00170b..425764b1c88d2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/preference/SearchPreferenceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/preference/SearchPreferenceIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.preference;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.search.SearchRequestBuilder;
@@ -41,20 +43,25 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.node.Node;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -64,7 +71,24 @@
 import static org.hamcrest.Matchers.not;
 
 @OpenSearchIntegTestCase.ClusterScope(minNumDataNodes = 2)
-public class SearchPreferenceIT extends OpenSearchIntegTestCase {
+public class SearchPreferenceIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchPreferenceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     public Settings nodeSettings(int nodeOrdinal) {
@@ -89,7 +113,9 @@ public void testStopOneNodePreferenceWithRedState() throws IOException {
         internalCluster().stopRandomDataNode();
         client().admin().cluster().prepareHealth().setWaitForStatus(ClusterHealthStatus.RED).get();
         String[] preferences = new String[] {
+            "_primary",
             "_local",
+            "_primary_first",
             "_prefer_nodes:somenode",
             "_prefer_nodes:server2",
             "_prefer_nodes:somenode,server2" };
@@ -134,7 +160,7 @@ public void testNoPreferenceRandom() {
     }
 
     public void testSimplePreference() {
-        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 1}", XContentType.JSON).get();
+        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 1}", MediaTypeRegistry.JSON).get();
         ensureGreen();
 
         client().prepareIndex("test").setSource("field1", "value1").get();
@@ -143,11 +169,24 @@ public void testSimplePreference() {
         SearchResponse searchResponse = client().prepareSearch().setQuery(matchAllQuery()).get();
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
 
-        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_local").get();
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_local").execute().actionGet();
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
 
-        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("1234").get();
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_primary").execute().actionGet();
         assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
+
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_primary_first").execute().actionGet();
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
+
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_replica").execute().actionGet();
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
+
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_replica_first").execute().actionGet();
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
+
+        searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setPreference("1234").execute().actionGet();
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(1L));
+
     }
 
     public void testThatSpecifyingNonExistingNodesReturnsUsefulError() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/profile/ProfilerSingleNodeNetworkTest.java b/server/src/internalClusterTest/java/org/opensearch/search/profile/ProfilerSingleNodeNetworkTest.java
index 12d68c9c38ca1..de7677e3b3708 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/profile/ProfilerSingleNodeNetworkTest.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/profile/ProfilerSingleNodeNetworkTest.java
@@ -18,9 +18,9 @@
 import java.util.List;
 import java.util.Map;
 
+import static org.opensearch.search.profile.query.RandomQueryGenerator.randomQueryBuilder;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
-import static org.opensearch.search.profile.query.RandomQueryGenerator.randomQueryBuilder;
 
 public class ProfilerSingleNodeNetworkTest extends OpenSearchSingleNodeTestCase {
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/profile/aggregation/AggregationProfilerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/profile/aggregation/AggregationProfilerIT.java
index f3d1a479f1b46..82dd6225fda4e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/profile/aggregation/AggregationProfilerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/profile/aggregation/AggregationProfilerIT.java
@@ -32,44 +32,66 @@
 
 package org.opensearch.search.profile.aggregation;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.sampler.DiversifiedOrdinalsSamplerAggregator;
 import org.opensearch.search.aggregations.bucket.terms.GlobalOrdinalsStringTermsAggregator;
+import org.opensearch.search.aggregations.metrics.Stats;
 import org.opensearch.search.profile.ProfileResult;
 import org.opensearch.search.profile.ProfileShardResult;
+import org.opensearch.search.profile.query.CollectorResult;
+import org.opensearch.search.profile.query.QueryProfileShardResult;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+import org.hamcrest.core.IsNull;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.avg;
 import static org.opensearch.search.aggregations.AggregationBuilders.diversifiedSampler;
+import static org.opensearch.search.aggregations.AggregationBuilders.global;
 import static org.opensearch.search.aggregations.AggregationBuilders.histogram;
 import static org.opensearch.search.aggregations.AggregationBuilders.max;
+import static org.opensearch.search.aggregations.AggregationBuilders.stats;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.hasEntry;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.sameInstance;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public class AggregationProfilerIT extends OpenSearchIntegTestCase {
+public class AggregationProfilerIT extends ParameterizedOpenSearchIntegTestCase {
+
     private static final String BUILD_LEAF_COLLECTOR = AggregationTimingType.BUILD_LEAF_COLLECTOR.toString();
     private static final String COLLECT = AggregationTimingType.COLLECT.toString();
     private static final String POST_COLLECTION = AggregationTimingType.POST_COLLECTION.toString();
     private static final String INITIALIZE = AggregationTimingType.INITIALIZE.toString();
     private static final String BUILD_AGGREGATION = AggregationTimingType.BUILD_AGGREGATION.toString();
     private static final String REDUCE = AggregationTimingType.REDUCE.toString();
-    private static final Set<String> BREAKDOWN_KEYS = org.opensearch.common.collect.Set.of(
+    private static final Set<String> BREAKDOWN_KEYS = Set.of(
         INITIALIZE,
         BUILD_LEAF_COLLECTOR,
         COLLECT,
@@ -81,7 +103,52 @@ public class AggregationProfilerIT extends OpenSearchIntegTestCase {
         COLLECT + "_count",
         POST_COLLECTION + "_count",
         BUILD_AGGREGATION + "_count",
-        REDUCE + "_count"
+        REDUCE + "_count",
+        INITIALIZE + "_start_time",
+        BUILD_LEAF_COLLECTOR + "_start_time",
+        COLLECT + "_start_time",
+        POST_COLLECTION + "_start_time",
+        BUILD_AGGREGATION + "_start_time",
+        REDUCE + "_start_time"
+    );
+
+    private static final Set<String> CONCURRENT_SEARCH_BREAKDOWN_KEYS = Set.of(
+        INITIALIZE,
+        BUILD_LEAF_COLLECTOR,
+        COLLECT,
+        POST_COLLECTION,
+        BUILD_AGGREGATION,
+        REDUCE,
+        INITIALIZE + "_count",
+        BUILD_LEAF_COLLECTOR + "_count",
+        COLLECT + "_count",
+        POST_COLLECTION + "_count",
+        BUILD_AGGREGATION + "_count",
+        REDUCE + "_count",
+        "max_" + INITIALIZE,
+        "max_" + BUILD_LEAF_COLLECTOR,
+        "max_" + COLLECT,
+        "max_" + POST_COLLECTION,
+        "max_" + BUILD_AGGREGATION,
+        "max_" + REDUCE,
+        "min_" + INITIALIZE,
+        "min_" + BUILD_LEAF_COLLECTOR,
+        "min_" + COLLECT,
+        "min_" + POST_COLLECTION,
+        "min_" + BUILD_AGGREGATION,
+        "min_" + REDUCE,
+        "avg_" + INITIALIZE,
+        "avg_" + BUILD_LEAF_COLLECTOR,
+        "avg_" + COLLECT,
+        "avg_" + POST_COLLECTION,
+        "avg_" + BUILD_AGGREGATION,
+        "avg_" + REDUCE,
+        "max_" + BUILD_LEAF_COLLECTOR + "_count",
+        "max_" + COLLECT + "_count",
+        "min_" + BUILD_LEAF_COLLECTOR + "_count",
+        "min_" + COLLECT + "_count",
+        "avg_" + BUILD_LEAF_COLLECTOR + "_count",
+        "avg_" + COLLECT + "_count"
     );
 
     private static final String TOTAL_BUCKETS = "total_buckets";
@@ -95,6 +162,26 @@ public class AggregationProfilerIT extends OpenSearchIntegTestCase {
     private static final String NUMBER_FIELD = "number";
     private static final String TAG_FIELD = "tag";
     private static final String STRING_FIELD = "string_field";
+    private final int numDocs = 5;
+    private static final String REASON_SEARCH_TOP_HITS = "search_top_hits";
+    private static final String REASON_AGGREGATION = "aggregation";
+
+    public AggregationProfilerIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected int numberOfShards() {
@@ -107,7 +194,7 @@ protected void setupSuiteScopeCluster() throws Exception {
             client().admin()
                 .indices()
                 .prepareCreate("idx")
-                .setSettings(org.opensearch.common.collect.Map.of("number_of_shards", 1, "number_of_replicas", 0))
+                .setSettings(Map.of("number_of_shards", 1, "number_of_replicas", 0))
                 .setMapping(STRING_FIELD, "type=keyword", NUMBER_FIELD, "type=integer", TAG_FIELD, "type=keyword")
                 .get()
         );
@@ -118,7 +205,7 @@ protected void setupSuiteScopeCluster() throws Exception {
             randomStrings[i] = randomAlphaOfLength(10);
         }
 
-        for (int i = 0; i < 5; i++) {
+        for (int i = 0; i < numDocs; i++) {
             builders.add(
                 client().prepareIndex("idx")
                     .setSource(
@@ -159,14 +246,25 @@ public void testSimpleProfile() {
             assertThat(histoAggResult.getTime(), greaterThan(0L));
             Map<String, Long> breakdown = histoAggResult.getTimeBreakdown();
             assertThat(breakdown, notNullValue());
-            assertThat(breakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (histoAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(breakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                }
+            } else {
+                assertThat(breakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 2);
+                }
+            }
             assertThat(breakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(breakdown.get(COLLECT), greaterThan(0L));
             assertThat(breakdown.get(BUILD_AGGREGATION).longValue(), greaterThan(0L));
             assertThat(breakdown.get(REDUCE), equalTo(0L));
             Map<String, Object> debug = histoAggResult.getDebugInfo();
             assertThat(debug, notNullValue());
-            assertThat(debug.keySet(), equalTo(org.opensearch.common.collect.Set.of(TOTAL_BUCKETS)));
+            assertThat(debug.keySet(), equalTo(Set.of(TOTAL_BUCKETS)));
             assertThat(((Number) debug.get(TOTAL_BUCKETS)).longValue(), greaterThan(0L));
         }
     }
@@ -202,14 +300,25 @@ public void testMultiLevelProfile() {
             assertThat(histoAggResult.getTime(), greaterThan(0L));
             Map<String, Long> histoBreakdown = histoAggResult.getTimeBreakdown();
             assertThat(histoBreakdown, notNullValue());
-            assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (histoAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(histoBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                }
+            } else {
+                assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 2);
+                }
+            }
             assertThat(histoBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(histoBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(histoBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(histoBreakdown.get(REDUCE), equalTo(0L));
             Map<String, Object> histoDebugInfo = histoAggResult.getDebugInfo();
             assertThat(histoDebugInfo, notNullValue());
-            assertThat(histoDebugInfo.keySet(), equalTo(org.opensearch.common.collect.Set.of(TOTAL_BUCKETS)));
+            assertThat(histoDebugInfo.keySet(), equalTo(Set.of(TOTAL_BUCKETS)));
             assertThat(((Number) histoDebugInfo.get(TOTAL_BUCKETS)).longValue(), greaterThan(0L));
             assertThat(histoAggResult.getProfiledChildren().size(), equalTo(1));
 
@@ -220,7 +329,12 @@ public void testMultiLevelProfile() {
             assertThat(termsAggResult.getTime(), greaterThan(0L));
             Map<String, Long> termsBreakdown = termsAggResult.getTimeBreakdown();
             assertThat(termsBreakdown, notNullValue());
-            assertThat(termsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (termsAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(termsBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(termsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(termsBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(termsBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(termsBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
@@ -235,12 +349,17 @@ public void testMultiLevelProfile() {
             assertThat(avgAggResult.getTime(), greaterThan(0L));
             Map<String, Long> avgBreakdown = termsAggResult.getTimeBreakdown();
             assertThat(avgBreakdown, notNullValue());
-            assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (avgAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(avgBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(avgBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(avgBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(avgBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(avgAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(avgAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(avgAggResult.getProfiledChildren().size(), equalTo(0));
         }
     }
@@ -288,14 +407,25 @@ public void testMultiLevelProfileBreadthFirst() {
             assertThat(histoAggResult.getTime(), greaterThan(0L));
             Map<String, Long> histoBreakdown = histoAggResult.getTimeBreakdown();
             assertThat(histoBreakdown, notNullValue());
-            assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (histoAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(histoBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                }
+            } else {
+                assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 2);
+                }
+            }
             assertThat(histoBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(histoBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(histoBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(histoBreakdown.get(REDUCE), equalTo(0L));
             Map<String, Object> histoDebugInfo = histoAggResult.getDebugInfo();
             assertThat(histoDebugInfo, notNullValue());
-            assertThat(histoDebugInfo.keySet(), equalTo(org.opensearch.common.collect.Set.of(TOTAL_BUCKETS)));
+            assertThat(histoDebugInfo.keySet(), equalTo(Set.of(TOTAL_BUCKETS)));
             assertThat(((Number) histoDebugInfo.get(TOTAL_BUCKETS)).longValue(), greaterThan(0L));
             assertThat(histoAggResult.getProfiledChildren().size(), equalTo(1));
 
@@ -306,7 +436,12 @@ public void testMultiLevelProfileBreadthFirst() {
             assertThat(termsAggResult.getTime(), greaterThan(0L));
             Map<String, Long> termsBreakdown = termsAggResult.getTimeBreakdown();
             assertThat(termsBreakdown, notNullValue());
-            assertThat(termsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (termsAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(termsBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(termsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(termsBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(termsBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(termsBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
@@ -321,12 +456,17 @@ public void testMultiLevelProfileBreadthFirst() {
             assertThat(avgAggResult.getTime(), greaterThan(0L));
             Map<String, Long> avgBreakdown = avgAggResult.getTimeBreakdown();
             assertThat(avgBreakdown, notNullValue());
-            assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (avgAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(avgBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(avgBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(avgBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(avgBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(avgAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(avgAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(avgAggResult.getProfiledChildren().size(), equalTo(0));
         }
     }
@@ -359,17 +499,25 @@ public void testDiversifiedAggProfile() {
             assertThat(diversifyAggResult.getTime(), greaterThan(0L));
             Map<String, Long> diversifyBreakdown = diversifyAggResult.getTimeBreakdown();
             assertThat(diversifyBreakdown, notNullValue());
-            assertThat(diversifyBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (diversifyAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(diversifyBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                }
+            } else {
+                assertThat(diversifyBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 2);
+                }
+            }
             assertThat(diversifyBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(diversifyBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(diversifyBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(diversifyBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(diversifyBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(diversifyBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(
-                diversifyAggResult.getDebugInfo(),
-                equalTo(org.opensearch.common.collect.Map.of(DEFERRED, org.opensearch.common.collect.List.of("max")))
-            );
+            assertThat(diversifyAggResult.getDebugInfo(), equalTo(Map.of(DEFERRED, List.of("max"))));
             assertThat(diversifyAggResult.getProfiledChildren().size(), equalTo(1));
 
             ProfileResult maxAggResult = diversifyAggResult.getProfiledChildren().get(0);
@@ -379,14 +527,19 @@ public void testDiversifiedAggProfile() {
             assertThat(maxAggResult.getTime(), greaterThan(0L));
             Map<String, Long> maxBreakdown = maxAggResult.getTimeBreakdown();
             assertThat(maxBreakdown, notNullValue());
-            assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (maxAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(maxBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(diversifyBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(diversifyBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(diversifyBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(diversifyBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(maxBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(maxAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(maxAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(maxAggResult.getProfiledChildren().size(), equalTo(0));
         }
     }
@@ -432,7 +585,18 @@ public void testComplexProfile() {
             assertThat(histoAggResult.getTime(), greaterThan(0L));
             Map<String, Long> histoBreakdown = histoAggResult.getTimeBreakdown();
             assertThat(histoBreakdown, notNullValue());
-            assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (histoAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(histoBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                }
+            } else {
+                assertThat(histoBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 2);
+                }
+            }
             assertThat(histoBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(histoBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(histoBreakdown.get(COLLECT), greaterThan(0L));
@@ -441,7 +605,7 @@ public void testComplexProfile() {
             assertThat(histoBreakdown.get(REDUCE), equalTo(0L));
             Map<String, Object> histoDebugInfo = histoAggResult.getDebugInfo();
             assertThat(histoDebugInfo, notNullValue());
-            assertThat(histoDebugInfo.keySet(), equalTo(org.opensearch.common.collect.Set.of(TOTAL_BUCKETS)));
+            assertThat(histoDebugInfo.keySet(), equalTo(Set.of(TOTAL_BUCKETS)));
             assertThat(((Number) histoDebugInfo.get(TOTAL_BUCKETS)).longValue(), greaterThan(0L));
             assertThat(histoAggResult.getProfiledChildren().size(), equalTo(2));
 
@@ -455,7 +619,12 @@ public void testComplexProfile() {
             assertThat(tagsAggResult.getTime(), greaterThan(0L));
             Map<String, Long> tagsBreakdown = tagsAggResult.getTimeBreakdown();
             assertThat(tagsBreakdown, notNullValue());
-            assertThat(tagsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (tagsAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(tagsBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(tagsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(tagsBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(tagsBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(tagsBreakdown.get(COLLECT), greaterThan(0L));
@@ -475,14 +644,19 @@ public void testComplexProfile() {
             assertThat(avgAggResult.getTime(), greaterThan(0L));
             Map<String, Long> avgBreakdown = avgAggResult.getTimeBreakdown();
             assertThat(avgBreakdown, notNullValue());
-            assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (avgAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(avgBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(avgBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(avgBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(avgBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(avgBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(avgAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(avgAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(avgAggResult.getProfiledChildren().size(), equalTo(0));
 
             ProfileResult maxAggResult = tagsAggResultSubAggregations.get("max");
@@ -491,14 +665,19 @@ public void testComplexProfile() {
             assertThat(maxAggResult.getTime(), greaterThan(0L));
             Map<String, Long> maxBreakdown = maxAggResult.getTimeBreakdown();
             assertThat(maxBreakdown, notNullValue());
-            assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (maxAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(maxBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(maxBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(maxBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(maxBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(maxBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(maxAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(maxAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(maxAggResult.getProfiledChildren().size(), equalTo(0));
 
             ProfileResult stringsAggResult = histoAggResultSubAggregations.get("strings");
@@ -507,7 +686,12 @@ public void testComplexProfile() {
             assertThat(stringsAggResult.getTime(), greaterThan(0L));
             Map<String, Long> stringsBreakdown = stringsAggResult.getTimeBreakdown();
             assertThat(stringsBreakdown, notNullValue());
-            assertThat(stringsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (stringsAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(stringsBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(stringsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(stringsBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(stringsBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(stringsBreakdown.get(COLLECT), greaterThan(0L));
@@ -527,14 +711,19 @@ public void testComplexProfile() {
             assertThat(avgAggResult.getTime(), greaterThan(0L));
             avgBreakdown = avgAggResult.getTimeBreakdown();
             assertThat(avgBreakdown, notNullValue());
-            assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (avgAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(avgBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(avgBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(avgBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(avgBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(avgBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(avgAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(avgAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(avgAggResult.getProfiledChildren().size(), equalTo(0));
 
             maxAggResult = stringsAggResultSubAggregations.get("max");
@@ -543,14 +732,19 @@ public void testComplexProfile() {
             assertThat(maxAggResult.getTime(), greaterThan(0L));
             maxBreakdown = maxAggResult.getTimeBreakdown();
             assertThat(maxBreakdown, notNullValue());
-            assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (maxAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(maxBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(maxBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(maxBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(maxBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(maxBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(maxAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(maxAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(maxAggResult.getProfiledChildren().size(), equalTo(0));
 
             tagsAggResult = stringsAggResultSubAggregations.get("tags");
@@ -560,7 +754,12 @@ public void testComplexProfile() {
             assertThat(tagsAggResult.getTime(), greaterThan(0L));
             tagsBreakdown = tagsAggResult.getTimeBreakdown();
             assertThat(tagsBreakdown, notNullValue());
-            assertThat(tagsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (tagsAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(tagsBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(tagsBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(tagsBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(tagsBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(tagsBreakdown.get(COLLECT), greaterThan(0L));
@@ -580,14 +779,19 @@ public void testComplexProfile() {
             assertThat(avgAggResult.getTime(), greaterThan(0L));
             avgBreakdown = avgAggResult.getTimeBreakdown();
             assertThat(avgBreakdown, notNullValue());
-            assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (avgAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(avgBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(avgBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(avgBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(avgBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(avgBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(avgBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(avgBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(avgAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(avgAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(avgAggResult.getProfiledChildren().size(), equalTo(0));
 
             maxAggResult = tagsAggResultSubAggregations.get("max");
@@ -596,14 +800,19 @@ public void testComplexProfile() {
             assertThat(maxAggResult.getTime(), greaterThan(0L));
             maxBreakdown = maxAggResult.getTimeBreakdown();
             assertThat(maxBreakdown, notNullValue());
-            assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            if (maxAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertThat(maxBreakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+            } else {
+                assertThat(maxBreakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+            }
             assertThat(maxBreakdown.get(INITIALIZE), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_LEAF_COLLECTOR), greaterThan(0L));
             assertThat(maxBreakdown.get(COLLECT), greaterThan(0L));
             assertThat(maxBreakdown.get(POST_COLLECTION), greaterThan(0L));
             assertThat(maxBreakdown.get(BUILD_AGGREGATION), greaterThan(0L));
             assertThat(maxBreakdown.get(REDUCE), equalTo(0L));
-            assertThat(maxAggResult.getDebugInfo(), equalTo(org.opensearch.common.collect.Map.of()));
+            assertThat(maxAggResult.getDebugInfo(), equalTo(Map.of()));
             assertThat(maxAggResult.getProfiledChildren().size(), equalTo(0));
         }
     }
@@ -636,4 +845,165 @@ public void testNoProfile() {
         assertThat(profileResults, notNullValue());
         assertThat(profileResults.size(), equalTo(0));
     }
+
+    public void testGlobalAggWithStatsSubAggregatorProfile() {
+        boolean profileEnabled = true;
+        SearchResponse response = client().prepareSearch("idx")
+            .addAggregation(global("global").subAggregation(stats("value_stats").field(NUMBER_FIELD)))
+            .setProfile(profileEnabled)
+            .get();
+
+        assertSearchResponse(response);
+        Global global = response.getAggregations().get("global");
+        assertThat(global, IsNull.notNullValue());
+        assertThat(global.getName(), equalTo("global"));
+        assertThat(global.getDocCount(), equalTo((long) numDocs));
+        assertThat((long) ((InternalAggregation) global).getProperty("_count"), equalTo((long) numDocs));
+        assertThat(global.getAggregations().asList().isEmpty(), is(false));
+
+        Stats stats = global.getAggregations().get("value_stats");
+        assertThat((Stats) ((InternalAggregation) global).getProperty("value_stats"), sameInstance(stats));
+        assertThat(stats, IsNull.notNullValue());
+        assertThat(stats.getName(), equalTo("value_stats"));
+
+        Map<String, ProfileShardResult> profileResults = response.getProfileResults();
+        assertThat(profileResults, notNullValue());
+        assertThat(profileResults.size(), equalTo(getNumShards("idx").numPrimaries));
+        for (ProfileShardResult profileShardResult : profileResults.values()) {
+            assertThat(profileShardResult, notNullValue());
+            List<QueryProfileShardResult> queryProfileShardResults = profileShardResult.getQueryProfileResults();
+            assertEquals(queryProfileShardResults.size(), 2);
+            // ensure there is no multi collector getting added with only global agg
+            for (QueryProfileShardResult queryProfileShardResult : queryProfileShardResults) {
+                assertEquals(queryProfileShardResult.getQueryResults().size(), 1);
+                if (queryProfileShardResult.getQueryResults().get(0).getQueryName().equals("MatchAllDocsQuery")) {
+                    assertEquals(0, queryProfileShardResult.getQueryResults().get(0).getProfiledChildren().size());
+                    assertEquals("search_top_hits", queryProfileShardResult.getCollectorResult().getReason());
+                    assertEquals(0, queryProfileShardResult.getCollectorResult().getProfiledChildren().size());
+                } else if (queryProfileShardResult.getQueryResults().get(0).getQueryName().equals("ConstantScoreQuery")) {
+                    assertEquals(1, queryProfileShardResult.getQueryResults().get(0).getProfiledChildren().size());
+                    assertEquals("aggregation_global", queryProfileShardResult.getCollectorResult().getReason());
+                    assertEquals(0, queryProfileShardResult.getCollectorResult().getProfiledChildren().size());
+                } else {
+                    fail("unexpected profile shard result in the response");
+                }
+            }
+            AggregationProfileShardResult aggProfileResults = profileShardResult.getAggregationProfileResults();
+            assertThat(aggProfileResults, notNullValue());
+            List<ProfileResult> aggProfileResultsList = aggProfileResults.getProfileResults();
+            assertThat(aggProfileResultsList, notNullValue());
+            assertEquals(1, aggProfileResultsList.size());
+            ProfileResult globalAggResult = aggProfileResultsList.get(0);
+            assertThat(globalAggResult, notNullValue());
+            assertEquals("GlobalAggregator", globalAggResult.getQueryName());
+            assertEquals("global", globalAggResult.getLuceneDescription());
+            assertEquals(1, globalAggResult.getProfiledChildren().size());
+            assertThat(globalAggResult.getTime(), greaterThan(0L));
+            Map<String, Long> breakdown = globalAggResult.getTimeBreakdown();
+            assertThat(breakdown, notNullValue());
+            if (globalAggResult.getMaxSliceTime() != null) {
+                // concurrent segment search enabled
+                assertEquals(CONCURRENT_SEARCH_BREAKDOWN_KEYS, breakdown.keySet());
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 0);
+                }
+            } else {
+                assertEquals(BREAKDOWN_KEYS, breakdown.keySet());
+                for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                    assertCollectorResult(collectorResult, 0);
+                }
+            }
+            assertThat(breakdown.get(INITIALIZE), greaterThan(0L));
+            assertThat(breakdown.get(COLLECT), greaterThan(0L));
+            assertThat(breakdown.get(BUILD_AGGREGATION).longValue(), greaterThan(0L));
+            assertEquals(0, breakdown.get(REDUCE).intValue());
+        }
+    }
+
+    public void testMultipleAggregationsProfile() {
+        SearchResponse response = client().prepareSearch("idx")
+            .setProfile(true)
+            .addAggregation(histogram("histo_1").field(NUMBER_FIELD).interval(1L))
+            .addAggregation(histogram("histo_2").field(NUMBER_FIELD).interval(1L))
+            .get();
+        assertSearchResponse(response);
+        Map<String, ProfileShardResult> profileResults = response.getProfileResults();
+        assertThat(profileResults, notNullValue());
+        assertThat(profileResults.size(), equalTo(getNumShards("idx").numPrimaries));
+        for (ProfileShardResult profileShardResult : profileResults.values()) {
+            assertThat(profileShardResult, notNullValue());
+            List<QueryProfileShardResult> queryProfilerResults = profileShardResult.getQueryProfileResults();
+            assertThat(queryProfilerResults, notNullValue());
+            for (QueryProfileShardResult queryProfilerResult : queryProfilerResults) {
+                CollectorResult collectorResult = queryProfilerResult.getCollectorResult();
+                String reason = collectorResult.getReason();
+                assertThat(reason, equalTo("search_multi"));
+                List<CollectorResult> children = collectorResult.getProfiledChildren();
+                assertThat(children.size(), equalTo(2));
+                assertThat(children.get(1).getName(), containsString("[histo_1, histo_2]"));
+            }
+            AggregationProfileShardResult aggProfileResults = profileShardResult.getAggregationProfileResults();
+            assertThat(aggProfileResults, notNullValue());
+            List<ProfileResult> aggProfileResultsList = aggProfileResults.getProfileResults();
+            assertThat(aggProfileResultsList, notNullValue());
+            assertThat(aggProfileResultsList.size(), equalTo(2));
+            for (ProfileResult histoAggResult : aggProfileResultsList) {
+                assertThat(histoAggResult, notNullValue());
+                assertThat(histoAggResult.getQueryName(), equalTo("NumericHistogramAggregator"));
+                assertThat(histoAggResult.getLuceneDescription(), containsString("histo_"));
+                assertThat(histoAggResult.getProfiledChildren().size(), equalTo(0));
+                assertThat(histoAggResult.getTime(), greaterThan(0L));
+                Map<String, Long> breakdown = histoAggResult.getTimeBreakdown();
+                assertThat(breakdown, notNullValue());
+                if (histoAggResult.getMaxSliceTime() != null) {
+                    // concurrent segment search enabled
+                    assertThat(breakdown.keySet(), equalTo(CONCURRENT_SEARCH_BREAKDOWN_KEYS));
+                    for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                        assertCollectorResultWithConcurrentSearchEnabled(collectorResult, 2);
+                    }
+                } else {
+                    assertThat(breakdown.keySet(), equalTo(BREAKDOWN_KEYS));
+                    for (QueryProfileShardResult collectorResult : profileShardResult.getQueryProfileResults()) {
+                        assertCollectorResult(collectorResult, 2);
+                    }
+                }
+                assertThat(breakdown.get(INITIALIZE), greaterThan(0L));
+                assertThat(breakdown.get(COLLECT), greaterThan(0L));
+                assertThat(breakdown.get(BUILD_AGGREGATION).longValue(), greaterThan(0L));
+                assertThat(breakdown.get(REDUCE), equalTo(0L));
+                Map<String, Object> debug = histoAggResult.getDebugInfo();
+                assertThat(debug, notNullValue());
+                assertThat(debug.keySet(), equalTo(Set.of(TOTAL_BUCKETS)));
+                assertThat(((Number) debug.get(TOTAL_BUCKETS)).longValue(), greaterThan(0L));
+            }
+        }
+    }
+
+    private void assertCollectorResult(QueryProfileShardResult collectorResult, int expectedChildrenCount) {
+        long nodeTime = collectorResult.getCollectorResult().getTime();
+        assertThat(collectorResult.getCollectorResult().getMaxSliceTime(), equalTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getMinSliceTime(), equalTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getAvgSliceTime(), equalTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getReduceTime(), equalTo(0L));
+        assertThat(collectorResult.getCollectorResult().getSliceCount(), equalTo(1));
+        assertThat(collectorResult.getCollectorResult().getProfiledChildren().size(), equalTo(expectedChildrenCount));
+        if (expectedChildrenCount == 2) {
+            assertThat(collectorResult.getCollectorResult().getProfiledChildren().get(0).getReason(), equalTo(REASON_SEARCH_TOP_HITS));
+            assertThat(collectorResult.getCollectorResult().getProfiledChildren().get(1).getReason(), equalTo(REASON_AGGREGATION));
+        }
+    }
+
+    private void assertCollectorResultWithConcurrentSearchEnabled(QueryProfileShardResult collectorResult, int expectedChildrenCount) {
+        long nodeTime = collectorResult.getCollectorResult().getTime();
+        assertThat(collectorResult.getCollectorResult().getMaxSliceTime(), lessThanOrEqualTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getMinSliceTime(), lessThanOrEqualTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getAvgSliceTime(), lessThanOrEqualTo(nodeTime));
+        assertThat(collectorResult.getCollectorResult().getReduceTime(), greaterThan(0L));
+        assertThat(collectorResult.getCollectorResult().getSliceCount(), greaterThanOrEqualTo(1));
+        assertThat(collectorResult.getCollectorResult().getProfiledChildren().size(), equalTo(expectedChildrenCount));
+        if (expectedChildrenCount == 2) {
+            assertThat(collectorResult.getCollectorResult().getProfiledChildren().get(0).getReason(), equalTo(REASON_SEARCH_TOP_HITS));
+            assertThat(collectorResult.getCollectorResult().getProfiledChildren().get(1).getReason(), equalTo(REASON_AGGREGATION));
+        }
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/profile/query/QueryProfilerIT.java b/server/src/internalClusterTest/java/org/opensearch/search/profile/query/QueryProfilerIT.java
index a74f359f2542e..5f794d2abf878 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/profile/query/QueryProfilerIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/profile/query/QueryProfilerIT.java
@@ -34,7 +34,11 @@
 
 import org.apache.lucene.tests.util.English;
 import org.opensearch.action.index.IndexRequestBuilder;
-import org.opensearch.action.search.*;
+import org.opensearch.action.search.MultiSearchResponse;
+import org.opensearch.action.search.SearchRequestBuilder;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchType;
+import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -44,15 +48,19 @@
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
-import static org.hamcrest.Matchers.is;
+import static org.opensearch.search.profile.query.RandomQueryGenerator.randomQueryBuilder;
+import static org.hamcrest.Matchers.emptyOrNullString;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.emptyOrNullString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.opensearch.search.profile.query.RandomQueryGenerator.randomQueryBuilder;
 
 public class QueryProfilerIT extends OpenSearchIntegTestCase {
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/ExistsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/ExistsIT.java
index 75b8e46802061..e3253ea583ac2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/ExistsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/ExistsIT.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.explain.ExplainResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.SearchHit;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -52,11 +57,29 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 
-public class ExistsIT extends OpenSearchIntegTestCase {
+public class ExistsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ExistsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     // TODO: move this to a unit test somewhere...
     public void testEmptyIndex() throws Exception {
@@ -140,14 +163,7 @@ public void testExists() throws Exception {
             assertSearchResponse(resp);
             try {
                 assertEquals(
-                    String.format(
-                        Locale.ROOT,
-                        "exists(%s, %d) mapping: %s response: %s",
-                        fieldName,
-                        count,
-                        Strings.toString(mapping),
-                        resp
-                    ),
+                    String.format(Locale.ROOT, "exists(%s, %d) mapping: %s response: %s", fieldName, count, mapping.toString(), resp),
                     count,
                     resp.getHits().getTotalHits().value
                 );
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/MultiMatchQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/MultiMatchQueryIT.java
index d87bbfb1fb69c..457114bac33b8 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/MultiMatchQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/MultiMatchQueryIT.java
@@ -31,15 +31,18 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.MultiMatchQueryBuilder;
 import org.opensearch.index.query.Operator;
@@ -50,13 +53,13 @@
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.MockKeywordPlugin;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -73,6 +76,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.multiMatchQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -88,7 +92,24 @@
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.lessThan;
 
-public class MultiMatchQueryIT extends OpenSearchIntegTestCase {
+public class MultiMatchQueryIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MultiMatchQueryIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -1024,7 +1045,7 @@ public void testFuzzyFieldLevelBoosting() throws InterruptedException, Execution
 
         SearchResponse searchResponse = client().prepareSearch(idx)
             .setExplain(true)
-            .setQuery(multiMatchQuery("foo").field("title", 100).field("body").fuzziness(0))
+            .setQuery(multiMatchQuery("foo").field("title", 100).field("body").fuzziness(Fuzziness.ZERO))
             .get();
         SearchHit[] hits = searchResponse.getHits().getHits();
         assertNotEquals("both documents should be on different shards", hits[0].getShard().getShardId(), hits[1].getShard().getShardId());
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/QueryStringIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/QueryStringIT.java
index 5c7e53fda3f23..099eb934f4f4d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/QueryStringIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/QueryStringIT.java
@@ -32,30 +32,36 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.Operator;
 import org.opensearch.index.query.QueryStringQueryBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.SearchModule;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.Before;
 import org.junit.BeforeClass;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.StreamsUtils.copyToStringFromClasspath;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -64,10 +70,27 @@
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
-public class QueryStringIT extends OpenSearchIntegTestCase {
+public class QueryStringIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static int CLUSTER_MAX_CLAUSE_COUNT;
 
+    public QueryStringIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @BeforeClass
     public static void createRandomClusterSetting() {
         CLUSTER_MAX_CLAUSE_COUNT = randomIntBetween(50, 100);
@@ -76,7 +99,7 @@ public static void createRandomClusterSetting() {
     @Before
     public void setup() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
     }
 
@@ -161,7 +184,7 @@ public void testWithLotsOfTypes() throws Exception {
     public void testDocWithAllTypes() throws Exception {
         List<IndexRequestBuilder> reqs = new ArrayList<>();
         String docBody = copyToStringFromClasspath("/org/opensearch/search/query/all-example-document.json");
-        reqs.add(client().prepareIndex("test").setId("1").setSource(docBody, XContentType.JSON));
+        reqs.add(client().prepareIndex("test").setId("1").setSource(docBody, MediaTypeRegistry.JSON));
         indexRandom(true, false, reqs);
 
         SearchResponse resp = client().prepareSearch("test").setQuery(queryStringQuery("foo")).get();
@@ -216,11 +239,44 @@ public void testKeywordWithWhitespace() throws Exception {
         assertHitCount(resp, 3L);
     }
 
+    public void testRegexCaseInsensitivity() throws Exception {
+        createIndex("messages");
+        List<IndexRequestBuilder> indexRequests = new ArrayList<>();
+        indexRequests.add(client().prepareIndex("messages").setId("1").setSource("message", "message: this is a TLS handshake"));
+        indexRequests.add(client().prepareIndex("messages").setId("2").setSource("message", "message: this is a tcp handshake"));
+        indexRandom(true, false, indexRequests);
+
+        SearchResponse response = client().prepareSearch("messages").setQuery(queryStringQuery("/TLS/").defaultField("message")).get();
+        assertNoFailures(response);
+        assertHitCount(response, 1);
+        assertHits(response.getHits(), "1");
+
+        response = client().prepareSearch("messages").setQuery(queryStringQuery("/tls/").defaultField("message")).get();
+        assertNoFailures(response);
+        assertHitCount(response, 1);
+        assertHits(response.getHits(), "1");
+
+        response = client().prepareSearch("messages").setQuery(queryStringQuery("/TCP/").defaultField("message")).get();
+        assertNoFailures(response);
+        assertHitCount(response, 1);
+        assertHits(response.getHits(), "2");
+
+        response = client().prepareSearch("messages").setQuery(queryStringQuery("/tcp/").defaultField("message")).get();
+        assertNoFailures(response);
+        assertHitCount(response, 1);
+        assertHits(response.getHits(), "2");
+
+        response = client().prepareSearch("messages").setQuery(queryStringQuery("/HANDSHAKE/").defaultField("message")).get();
+        assertNoFailures(response);
+        assertHitCount(response, 2);
+        assertHits(response.getHits(), "1", "2");
+    }
+
     public void testAllFields() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
 
         Settings.Builder settings = Settings.builder().put("index.query.default_field", "*");
-        prepareCreate("test_1").setSource(indexBody, XContentType.JSON).setSettings(settings).get();
+        prepareCreate("test_1").setSource(indexBody, MediaTypeRegistry.JSON).setSettings(settings).get();
         ensureGreen("test_1");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/ScriptScoreQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/ScriptScoreQueryIT.java
index d736365a6e236..7ba582811bbc2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/ScriptScoreQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/ScriptScoreQueryIT.java
@@ -32,10 +32,13 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.RangeQueryBuilder;
@@ -43,8 +46,9 @@
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -54,6 +58,7 @@
 import static org.opensearch.index.query.QueryBuilders.boolQuery;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
 import static org.opensearch.index.query.QueryBuilders.scriptScoreQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -62,7 +67,24 @@
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertThirdHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasScore;
 
-public class ScriptScoreQueryIT extends OpenSearchIntegTestCase {
+public class ScriptScoreQueryIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public ScriptScoreQueryIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/SearchQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/SearchQueryIT.java
index fed5561c1df64..53bded1fc493c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/SearchQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/SearchQueryIT.java
@@ -32,27 +32,30 @@
 
 package org.opensearch.search.query;
 
-import org.apache.lucene.tests.analysis.MockTokenizer;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.analysis.pattern.PatternReplaceCharFilter;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.join.ScoreMode;
-import org.apache.lucene.util.AttributeSource;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.tests.util.English;
-
+import org.apache.lucene.util.AttributeSource;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchType;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.lucene.search.SpanBooleanQueryRewriteWithMaxClause;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.CharFilterFactory;
 import org.opensearch.index.analysis.NormalizingCharFilterFactory;
 import org.opensearch.index.analysis.TokenizerFactory;
@@ -73,12 +76,11 @@
 import org.opensearch.indices.analysis.AnalysisModule.AnalysisProvider;
 import org.opensearch.plugins.AnalysisPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.AggregationBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.junit.annotations.TestIssueLogging;
 
 import java.io.IOException;
@@ -90,8 +92,10 @@
 import java.time.format.DateTimeFormatter;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Random;
+import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.regex.Pattern;
 
@@ -125,6 +129,7 @@
 import static org.opensearch.index.query.QueryBuilders.termsQuery;
 import static org.opensearch.index.query.QueryBuilders.wildcardQuery;
 import static org.opensearch.index.query.QueryBuilders.wrapperQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
@@ -137,11 +142,29 @@
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasId;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasScore;
 import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
-public class SearchQueryIT extends OpenSearchIntegTestCase {
+public class SearchQueryIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchQueryIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -760,21 +783,21 @@ public void testMatchQueryFuzzy() throws Exception {
             client().prepareIndex("test").setId("2").setSource("text", "Unity")
         );
 
-        SearchResponse searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("0")).get();
+        SearchResponse searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness(Fuzziness.ZERO)).get();
         assertHitCount(searchResponse, 0L);
 
-        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("1")).get();
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness(Fuzziness.ONE)).get();
         assertHitCount(searchResponse, 2L);
         assertSearchHits(searchResponse, "1", "2");
 
-        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("AUTO")).get();
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness(Fuzziness.AUTO)).get();
         assertHitCount(searchResponse, 2L);
         assertSearchHits(searchResponse, "1", "2");
 
-        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness("AUTO:5,7")).get();
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "uniy").fuzziness(Fuzziness.customAuto(5, 7))).get();
         assertHitCount(searchResponse, 0L);
 
-        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "unify").fuzziness("AUTO:5,7")).get();
+        searchResponse = client().prepareSearch().setQuery(matchQuery("text", "unify").fuzziness(Fuzziness.customAuto(5, 7))).get();
         assertHitCount(searchResponse, 1L);
         assertSearchHits(searchResponse, "2");
     }
@@ -1860,7 +1883,6 @@ public void testRangeQueryWithTimeZone() throws Exception {
      * on "Configuring IDEs And Running Tests".
      */
     public void testRangeQueryWithLocaleMapping() throws Exception {
-        assumeTrue("need java 9 for testing ", JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0);
         assert ("SPI,COMPAT".equals(System.getProperty("java.locale.providers"))) : "`-Djava.locale.providers=SPI,COMPAT` needs to be set";
 
         assertAcked(
@@ -1895,8 +1917,8 @@ public void testRangeQueryWithLocaleMapping() throws Exception {
     }
 
     public void testSearchEmptyDoc() {
-        assertAcked(prepareCreate("test").setSettings("{\"index.analysis.analyzer.default.type\":\"keyword\"}", XContentType.JSON));
-        client().prepareIndex("test").setId("1").setSource("{}", XContentType.JSON).get();
+        assertAcked(prepareCreate("test").setSettings("{\"index.analysis.analyzer.default.type\":\"keyword\"}", MediaTypeRegistry.JSON));
+        client().prepareIndex("test").setId("1").setSource("{}", MediaTypeRegistry.JSON).get();
 
         refresh();
         assertHitCount(client().prepareSearch().setQuery(matchAllQuery()).get(), 1L);
@@ -2091,8 +2113,14 @@ public void testWildcardQueryNormalizationOnTextField() {
         refresh();
 
         {
+            // test default case insensitivity: false
             WildcardQueryBuilder wildCardQuery = wildcardQuery("field1", "Bb*");
             SearchResponse searchResponse = client().prepareSearch().setQuery(wildCardQuery).get();
+            assertHitCount(searchResponse, 0L);
+
+            // test case insensitivity set to true
+            wildCardQuery = wildcardQuery("field1", "Bb*").caseInsensitive(true);
+            searchResponse = client().prepareSearch().setQuery(wildCardQuery).get();
             assertHitCount(searchResponse, 1L);
 
             wildCardQuery = wildcardQuery("field1", "bb*");
@@ -2101,6 +2129,24 @@ public void testWildcardQueryNormalizationOnTextField() {
         }
     }
 
+    /** tests wildcard case sensitivity */
+    public void testWildcardCaseSensitivity() {
+        assertAcked(prepareCreate("test").setMapping("field", "type=text"));
+        client().prepareIndex("test").setId("1").setSource("field", "lowercase text").get();
+        refresh();
+
+        // test case sensitive
+        SearchResponse response = client().prepareSearch("test").setQuery(wildcardQuery("field", "Text").caseInsensitive(false)).get();
+        assertNoFailures(response);
+        assertHitCount(response, 0);
+
+        // test case insensitive
+        response = client().prepareSearch("test").setQuery(wildcardQuery("field", "Text").caseInsensitive(true)).get();
+        assertNoFailures(response);
+        assertHitCount(response, 1);
+        assertHits(response.getHits(), "1");
+    }
+
     /**
      * Reserved characters should be excluded when the normalization is applied for keyword fields.
      * See https://github.com/elastic/elasticsearch/issues/46300 for details.
@@ -2177,4 +2223,16 @@ public void testIssueFuzzyInsideSpanMulti() {
         SearchResponse response = client().prepareSearch("test").setQuery(query).get();
         assertHitCount(response, 1);
     }
+
+    /**
+     * asserts the search response hits include the expected ids
+     */
+    private void assertHits(SearchHits hits, String... ids) {
+        assertThat(hits.getTotalHits().value, equalTo((long) ids.length));
+        Set<String> hitIds = new HashSet<>();
+        for (SearchHit hit : hits.getHits()) {
+            hitIds.add(hit.getId());
+        }
+        assertThat(hitIds, containsInAnyOrder(ids));
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/query/SimpleQueryStringIT.java b/server/src/internalClusterTest/java/org/opensearch/search/query/SimpleQueryStringIT.java
index e0391d9cbc971..384d2b7423e66 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/query/SimpleQueryStringIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/query/SimpleQueryStringIT.java
@@ -32,20 +32,21 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
-
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.PreConfiguredTokenFilter;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.BoolQueryBuilder;
@@ -59,12 +60,12 @@
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.junit.BeforeClass;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -78,6 +79,7 @@
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
 import static org.opensearch.index.query.QueryBuilders.simpleQueryStringQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.StreamsUtils.copyToStringFromClasspath;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
@@ -93,10 +95,27 @@
 /**
  * Tests for the {@code simple_query_string} query
  */
-public class SimpleQueryStringIT extends OpenSearchIntegTestCase {
+public class SimpleQueryStringIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static int CLUSTER_MAX_CLAUSE_COUNT;
 
+    public SimpleQueryStringIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @BeforeClass
     public static void createRandomClusterSetting() {
         CLUSTER_MAX_CLAUSE_COUNT = randomIntBetween(60, 100);
@@ -373,17 +392,16 @@ public void testLenientFlagBeingTooLenient() throws Exception {
     }
 
     public void testSimpleQueryStringAnalyzeWildcard() throws ExecutionException, InterruptedException, IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "text")
-                .field("analyzer", "standard")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "text")
+            .field("analyzer", "standard")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         CreateIndexRequestBuilder mappingRequest = client().admin().indices().prepareCreate("test1").setMapping(mapping);
         mappingRequest.get();
@@ -420,17 +438,16 @@ public void testSimpleQueryStringOnIndexMetaField() throws Exception {
 
     public void testEmptySimpleQueryStringWithAnalysis() throws Exception {
         // https://github.com/elastic/elasticsearch/issues/18202
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("body")
-                .field("type", "text")
-                .field("analyzer", "stop")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("body")
+            .field("type", "text")
+            .field("analyzer", "stop")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         CreateIndexRequestBuilder mappingRequest = client().admin().indices().prepareCreate("test1").setMapping(mapping);
         mappingRequest.get();
@@ -444,7 +461,7 @@ public void testEmptySimpleQueryStringWithAnalysis() throws Exception {
 
     public void testBasicAllQuery() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
@@ -468,7 +485,7 @@ public void testBasicAllQuery() throws Exception {
 
     public void testWithDate() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
@@ -495,7 +512,7 @@ public void testWithDate() throws Exception {
 
     public void testWithLotsOfTypes() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
@@ -526,12 +543,12 @@ public void testWithLotsOfTypes() throws Exception {
 
     public void testDocWithAllTypes() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
         String docBody = copyToStringFromClasspath("/org/opensearch/search/query/all-example-document.json");
-        reqs.add(client().prepareIndex("test").setId("1").setSource(docBody, XContentType.JSON));
+        reqs.add(client().prepareIndex("test").setId("1").setSource(docBody, MediaTypeRegistry.JSON));
         indexRandom(true, false, reqs);
 
         SearchResponse resp = client().prepareSearch("test").setQuery(simpleQueryStringQuery("foo")).get();
@@ -571,7 +588,7 @@ public void testDocWithAllTypes() throws Exception {
 
     public void testKeywordWithWhitespace() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
@@ -591,7 +608,7 @@ public void testKeywordWithWhitespace() throws Exception {
 
     public void testAllFieldsWithSpecifiedLeniency() throws IOException {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
+        prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON).get();
         ensureGreen("test");
 
         SearchPhaseExecutionException e = expectThrows(
@@ -638,7 +655,7 @@ private void doAssertLimitExceededException(String field, int exceedingFieldCoun
 
     public void testFieldAlias() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        assertAcked(prepareCreate("test").setSource(indexBody, XContentType.JSON));
+        assertAcked(prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON));
         ensureGreen("test");
 
         List<IndexRequestBuilder> indexRequests = new ArrayList<>();
@@ -656,7 +673,7 @@ public void testFieldAlias() throws Exception {
 
     public void testFieldAliasWithWildcardField() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        assertAcked(prepareCreate("test").setSource(indexBody, XContentType.JSON));
+        assertAcked(prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON));
         ensureGreen("test");
 
         List<IndexRequestBuilder> indexRequests = new ArrayList<>();
@@ -674,7 +691,7 @@ public void testFieldAliasWithWildcardField() throws Exception {
 
     public void testFieldAliasOnDisallowedFieldType() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/opensearch/search/query/all-query-index.json");
-        assertAcked(prepareCreate("test").setSource(indexBody, XContentType.JSON));
+        assertAcked(prepareCreate("test").setSource(indexBody, MediaTypeRegistry.JSON));
         ensureGreen("test");
 
         List<IndexRequestBuilder> indexRequests = new ArrayList<>();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/scriptfilter/ScriptQuerySearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/scriptfilter/ScriptQuerySearchIT.java
index 5e45fd8d0ad2a..34967528f2c4f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/scriptfilter/ScriptQuerySearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/scriptfilter/ScriptQuerySearchIT.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.search.scriptfilter;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
@@ -45,8 +48,9 @@
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -61,12 +65,29 @@
 import static java.util.Collections.emptyMap;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.scriptQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
-public class ScriptQuerySearchIT extends OpenSearchIntegTestCase {
+public class ScriptQuerySearchIT extends ParameterizedOpenSearchIntegTestCase {
+    public ScriptQuerySearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/scroll/DuelScrollIT.java b/server/src/internalClusterTest/java/org/opensearch/search/scroll/DuelScrollIT.java
index 19cf1ee3a0ee7..c7a6d18f881c6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/scroll/DuelScrollIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/scroll/DuelScrollIT.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.scroll;
 
-import com.carrotsearch.hppc.IntHashSet;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -40,22 +40,44 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.sort.SortBuilder;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.Matchers.equalTo;
 
-public class DuelScrollIT extends OpenSearchIntegTestCase {
+public class DuelScrollIT extends ParameterizedOpenSearchIntegTestCase {
+    public DuelScrollIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testDuelQueryThenFetch() throws Exception {
         TestContext context = create(SearchType.DFS_QUERY_THEN_FETCH, SearchType.QUERY_THEN_FETCH);
 
@@ -145,7 +167,7 @@ private TestContext create(SearchType... searchTypes) throws Exception {
         boolean unevenRouting = randomBoolean();
 
         int numMissingDocs = scaledRandomIntBetween(0, numDocs / 100);
-        IntHashSet missingDocs = new IntHashSet(numMissingDocs);
+        final Set<Integer> missingDocs = new HashSet<>(numMissingDocs);
         for (int i = 0; i < numMissingDocs; i++) {
             while (!missingDocs.add(randomInt(numDocs))) {
             }
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollIT.java b/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollIT.java
index 3818566e2eb11..0eee136acac69 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.scroll;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.search.ClearScrollResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
@@ -41,28 +43,30 @@
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Priority;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.RangeQueryBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
-
 import org.junit.After;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
 
@@ -71,6 +75,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
@@ -87,7 +92,24 @@
 /**
  * Tests for scrolling.
  */
-public class SearchScrollIT extends OpenSearchIntegTestCase {
+public class SearchScrollIT extends ParameterizedOpenSearchIntegTestCase {
+    public SearchScrollIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @After
     public void cleanup() throws Exception {
         assertAcked(
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollWithFailingNodesIT.java b/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollWithFailingNodesIT.java
index a56f8667fab48..f16b9a4d67b49 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollWithFailingNodesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/scroll/SearchScrollWithFailingNodesIT.java
@@ -32,26 +32,50 @@
 
 package org.opensearch.search.scroll;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.lessThan;
 
-@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
-public class SearchScrollWithFailingNodesIT extends OpenSearchIntegTestCase {
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 2, numClientNodes = 0)
+public class SearchScrollWithFailingNodesIT extends ParameterizedOpenSearchIntegTestCase {
+    public SearchScrollWithFailingNodesIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected int numberOfShards() {
         return 2;
@@ -63,8 +87,6 @@ protected int numberOfReplicas() {
     }
 
     public void testScanScrollWithShardExceptions() throws Exception {
-        internalCluster().startNode();
-        internalCluster().startNode();
         assertAcked(
             prepareCreate("test")
                 // Enforces that only one shard can only be allocated to a single node
@@ -97,7 +119,7 @@ public void testScanScrollWithShardExceptions() throws Exception {
         assertThat(numHits, equalTo(100L));
         clearScroll("_all");
 
-        internalCluster().stopRandomNonMasterNode();
+        internalCluster().stopRandomNonClusterManagerNode();
 
         searchResponse = client().prepareSearch().setQuery(matchAllQuery()).setSize(10).setScroll(TimeValue.timeValueMinutes(1)).get();
         assertThat(searchResponse.getSuccessfulShards(), lessThan(searchResponse.getTotalShards()));
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/searchafter/SearchAfterIT.java b/server/src/internalClusterTest/java/org/opensearch/search/searchafter/SearchAfterIT.java
index 926e21294ffc8..00ac574b8bd72 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/searchafter/SearchAfterIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/searchafter/SearchAfterIT.java
@@ -32,35 +32,64 @@
 
 package org.opensearch.search.searchafter;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
+import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
-import java.util.List;
 import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.Collections;
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
 
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 
-public class SearchAfterIT extends OpenSearchIntegTestCase {
+public class SearchAfterIT extends ParameterizedOpenSearchIntegTestCase {
     private static final String INDEX_NAME = "test";
     private static final int NUM_DOCS = 100;
 
+    public SearchAfterIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testsShouldFail() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("test").setMapping("field1", "type=long", "field2", "type=keyword").get());
         ensureGreen();
@@ -155,6 +184,58 @@ public void testsShouldFail() throws Exception {
         }
     }
 
+    public void testPitWithSearchAfter() throws Exception {
+        assertAcked(client().admin().indices().prepareCreate("test").setMapping("field1", "type=long", "field2", "type=keyword").get());
+        ensureGreen();
+        indexRandom(
+            true,
+            client().prepareIndex("test").setId("0").setSource("field1", 0),
+            client().prepareIndex("test").setId("1").setSource("field1", 100, "field2", "toto"),
+            client().prepareIndex("test").setId("2").setSource("field1", 101),
+            client().prepareIndex("test").setId("3").setSource("field1", 99)
+        );
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "test" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        SearchResponse sr = client().prepareSearch()
+            .addSort("field1", SortOrder.ASC)
+            .setQuery(matchAllQuery())
+            .searchAfter(new Object[] { 99 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+            .get();
+        assertEquals(2, sr.getHits().getHits().length);
+        sr = client().prepareSearch()
+            .addSort("field1", SortOrder.ASC)
+            .setQuery(matchAllQuery())
+            .searchAfter(new Object[] { 100 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+            .get();
+        assertEquals(1, sr.getHits().getHits().length);
+        sr = client().prepareSearch()
+            .addSort("field1", SortOrder.ASC)
+            .setQuery(matchAllQuery())
+            .searchAfter(new Object[] { 0 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+            .get();
+        assertEquals(3, sr.getHits().getHits().length);
+        /**
+         * Add new data and assert PIT results remain the same and normal search results gets refreshed
+         */
+        indexRandom(true, client().prepareIndex("test").setId("4").setSource("field1", 102));
+        sr = client().prepareSearch()
+            .addSort("field1", SortOrder.ASC)
+            .setQuery(matchAllQuery())
+            .searchAfter(new Object[] { 0 })
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+            .get();
+        assertEquals(3, sr.getHits().getHits().length);
+        sr = client().prepareSearch().addSort("field1", SortOrder.ASC).setQuery(matchAllQuery()).searchAfter(new Object[] { 0 }).get();
+        assertEquals(4, sr.getHits().getHits().length);
+        client().admin().indices().prepareDelete("test").get();
+    }
+
     public void testWithNullStrings() throws InterruptedException {
         assertAcked(client().admin().indices().prepareCreate("test").setMapping("field2", "type=keyword").get());
         ensureGreen();
@@ -324,24 +405,22 @@ private void createIndexMappingsFromObjectType(String indexName, List<Object> ty
         ensureGreen();
     }
 
-    // Convert Integer, Short, Byte and Boolean to Long in order to match the conversion done
+    // Convert Integer, Short, Byte and Boolean to Int in order to match the conversion done
     // by the internal hits when populating the sort values.
     private List<Object> convertSortValues(List<Object> sortValues) {
         List<Object> converted = new ArrayList<>();
         for (int i = 0; i < sortValues.size(); i++) {
             Object from = sortValues.get(i);
-            if (from instanceof Integer) {
-                converted.add(((Integer) from).longValue());
-            } else if (from instanceof Short) {
-                converted.add(((Short) from).longValue());
+            if (from instanceof Short) {
+                converted.add(((Short) from).intValue());
             } else if (from instanceof Byte) {
-                converted.add(((Byte) from).longValue());
+                converted.add(((Byte) from).intValue());
             } else if (from instanceof Boolean) {
                 boolean b = (boolean) from;
                 if (b) {
-                    converted.add(1L);
+                    converted.add(1);
                 } else {
-                    converted.add(0L);
+                    converted.add(0);
                 }
             } else {
                 converted.add(from);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/simple/SimpleSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/simple/SimpleSearchIT.java
index 7382d4e157bc4..95b36311f6b8b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/simple/SimpleSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/simple/SimpleSearchIT.java
@@ -32,26 +32,31 @@
 
 package org.opensearch.search.simple;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
@@ -62,14 +67,34 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
 import static org.opensearch.index.query.QueryBuilders.rangeQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFailures;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.lucene.search.TotalHits.Relation.EQUAL_TO;
+import static org.apache.lucene.search.TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO;
+
+public class SimpleSearchIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SimpleSearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() }
+        );
+    }
 
-public class SimpleSearchIT extends OpenSearchIntegTestCase {
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public void testSearchNullIndex() {
         expectThrows(
@@ -99,7 +124,7 @@ public void testSearchRandomPreference() throws InterruptedException, ExecutionE
         int iters = scaledRandomIntBetween(10, 20);
         for (int i = 0; i < iters; i++) {
             String randomPreference = randomUnicodeOfLengthBetween(0, 4);
-            // randomPreference should not start with '_' (reserved for known preference types (e.g. _shards)
+            // randomPreference should not start with '_' (reserved for known preference types (e.g. _shards, _primary)
             while (randomPreference.startsWith("_")) {
                 randomPreference = randomUnicodeOfLengthBetween(0, 4);
             }
@@ -274,13 +299,18 @@ public void testSimpleTerminateAfterCount() throws Exception {
         refresh();
 
         SearchResponse searchResponse;
+        int size;
         for (int i = 1; i < max; i++) {
+            size = randomIntBetween(0, max);
             searchResponse = client().prepareSearch("test")
                 .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(max))
                 .setTerminateAfter(i)
+                .setSize(size)
+                .setTrackTotalHits(true)
                 .get();
             assertHitCount(searchResponse, i);
             assertTrue(searchResponse.isTerminatedEarly());
+            assertEquals(Math.min(i, size), searchResponse.getHits().getHits().length);
         }
 
         searchResponse = client().prepareSearch("test")
@@ -292,6 +322,83 @@ public void testSimpleTerminateAfterCount() throws Exception {
         assertFalse(searchResponse.isTerminatedEarly());
     }
 
+    public void testSimpleTerminateAfterTrackTotalHitsUpTo() throws Exception {
+        prepareCreate("test").setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0)).get();
+        ensureGreen();
+        int numDocs = 29;
+        List<IndexRequestBuilder> docbuilders = new ArrayList<>(numDocs);
+
+        for (int i = 1; i <= numDocs; i++) {
+            String id = String.valueOf(i);
+            docbuilders.add(client().prepareIndex("test").setId(id).setSource("field", i));
+        }
+
+        indexRandom(true, docbuilders);
+        ensureGreen();
+        refresh();
+
+        // size=0 is a special case where topDocsCollector is not added
+        int size = randomIntBetween(0, 1);
+        SearchResponse searchResponse;
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setTerminateAfter(10)
+            .setSize(size)
+            .setTrackTotalHitsUpTo(5)
+            .get();
+        assertTrue(searchResponse.isTerminatedEarly());
+        assertEquals(5, searchResponse.getHits().getTotalHits().value);
+        assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setTerminateAfter(5)
+            .setSize(size)
+            .setTrackTotalHitsUpTo(10)
+            .get();
+        assertTrue(searchResponse.isTerminatedEarly());
+        assertEquals(5, searchResponse.getHits().getTotalHits().value);
+        assertEquals(EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setTerminateAfter(5)
+            .setSize(size)
+            .setTrackTotalHitsUpTo(5)
+            .get();
+        assertTrue(searchResponse.isTerminatedEarly());
+        assertEquals(5, searchResponse.getHits().getTotalHits().value);
+        assertEquals(EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setTerminateAfter(5)
+            .setSize(size)
+            .setTrackTotalHits(true)
+            .get();
+        assertTrue(searchResponse.isTerminatedEarly());
+        assertEquals(5, searchResponse.getHits().getTotalHits().value);
+        assertEquals(EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setTerminateAfter(numDocs * 2)
+            .setSize(size)
+            .setTrackTotalHits(true)
+            .get();
+        assertFalse(searchResponse.isTerminatedEarly());
+        assertEquals(numDocs, searchResponse.getHits().getTotalHits().value);
+        assertEquals(EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+
+        searchResponse = client().prepareSearch("test")
+            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
+            .setSize(size)
+            .setTrackTotalHitsUpTo(5)
+            .get();
+        assertEquals(5, searchResponse.getHits().getTotalHits().value);
+        assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation);
+    }
+
     public void testSimpleIndexSortEarlyTerminate() throws Exception {
         prepareCreate("test").setSettings(
             Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0).put("index.sort.field", "rank")
@@ -326,7 +433,7 @@ public void testSimpleIndexSortEarlyTerminate() throws Exception {
 
     public void testInsaneFromAndSize() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertWindowFails(client().prepareSearch("idx").setFrom(Integer.MAX_VALUE));
         assertWindowFails(client().prepareSearch("idx").setSize(Integer.MAX_VALUE));
@@ -334,7 +441,7 @@ public void testInsaneFromAndSize() throws Exception {
 
     public void testTooLargeFromAndSize() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertWindowFails(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)));
         assertWindowFails(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1));
@@ -347,7 +454,7 @@ public void testTooLargeFromAndSize() throws Exception {
 
     public void testLargeFromAndSizeSucceeds() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) - 10).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
@@ -365,7 +472,7 @@ public void testTooLargeFromAndSizeOkBySetting() throws Exception {
             Settings.builder()
                 .put(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(), IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 2)
         ).get();
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1).get(), 1);
@@ -393,7 +500,7 @@ public void testTooLargeFromAndSizeOkByDynamicSetting() throws Exception {
                 )
                 .get()
         );
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1).get(), 1);
@@ -408,7 +515,7 @@ public void testTooLargeFromAndSizeOkByDynamicSetting() throws Exception {
 
     public void testTooLargeFromAndSizeBackwardsCompatibilityRecommendation() throws Exception {
         prepareCreate("idx").setSettings(Settings.builder().put(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(), Integer.MAX_VALUE)).get();
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 10).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 10).get(), 1);
@@ -423,7 +530,7 @@ public void testTooLargeFromAndSizeBackwardsCompatibilityRecommendation() throws
 
     public void testTooLargeRescoreWindow() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertRescoreWindowFails(Integer.MAX_VALUE);
         assertRescoreWindowFails(IndexSettings.MAX_RESCORE_WINDOW_SETTING.get(Settings.EMPTY) + 1);
@@ -433,7 +540,7 @@ public void testTooLargeRescoreOkBySetting() throws Exception {
         int defaultMaxWindow = IndexSettings.MAX_RESCORE_WINDOW_SETTING.get(Settings.EMPTY);
         prepareCreate("idx").setSettings(Settings.builder().put(IndexSettings.MAX_RESCORE_WINDOW_SETTING.getKey(), defaultMaxWindow * 2))
             .get();
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(
             client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -450,7 +557,7 @@ public void testTooLargeRescoreOkByResultWindowSetting() throws Exception {
                     defaultMaxWindow * 2
                 )
         ).get();
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(
             client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -468,7 +575,7 @@ public void testTooLargeRescoreOkByDynamicSetting() throws Exception {
                 .setSettings(Settings.builder().put(IndexSettings.MAX_RESCORE_WINDOW_SETTING.getKey(), defaultMaxWindow * 2))
                 .get()
         );
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(
             client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -489,7 +596,7 @@ public void testTooLargeRescoreOkByDynamicResultWindowSetting() throws Exception
                 )
                 .get()
         );
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         assertHitCount(
             client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -515,7 +622,7 @@ public void testTermQueryBigInt() throws Exception {
 
         client().prepareIndex("idx")
             .setId("1")
-            .setSource("{\"field\" : 80315953321748200608 }", XContentType.JSON)
+            .setSource("{\"field\" : 80315953321748200608 }", MediaTypeRegistry.JSON)
             .setRefreshPolicy(RefreshPolicy.IMMEDIATE)
             .get();
 
@@ -529,7 +636,7 @@ public void testTermQueryBigInt() throws Exception {
 
     public void testTooLongRegexInRegexpQuery() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx").setSource("{}", XContentType.JSON));
+        indexRandom(true, client().prepareIndex("idx").setSource("{}", MediaTypeRegistry.JSON));
 
         int defaultMaxRegexLength = IndexSettings.MAX_REGEX_LENGTH_SETTING.get(Settings.EMPTY);
         StringBuilder regexp = new StringBuilder(defaultMaxRegexLength);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/slice/SearchSliceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/slice/SearchSliceIT.java
index 9c735c42052e3..27a56f9d14f08 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/slice/SearchSliceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/slice/SearchSliceIT.java
@@ -32,61 +32,91 @@
 
 package org.opensearch.search.slice;
 
-import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
+import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchHit;
+import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.sort.SortBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
-import java.util.List;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
+import java.util.List;
 import java.util.concurrent.ExecutionException;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.startsWith;
 
-public class SearchSliceIT extends OpenSearchIntegTestCase {
-    private void setupIndex(int numDocs, int numberOfShards) throws IOException, ExecutionException, InterruptedException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("invalid_random_kw")
-                .field("type", "keyword")
-                .field("doc_values", "false")
-                .endObject()
-                .startObject("random_int")
-                .field("type", "integer")
-                .field("doc_values", "true")
-                .endObject()
-                .startObject("invalid_random_int")
-                .field("type", "integer")
-                .field("doc_values", "false")
-                .endObject()
-                .endObject()
-                .endObject()
+public class SearchSliceIT extends ParameterizedOpenSearchIntegTestCase {
+    public SearchSliceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
         );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    private void setupIndex(int numDocs, int numberOfShards) throws IOException, ExecutionException, InterruptedException {
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("invalid_random_kw")
+            .field("type", "keyword")
+            .field("doc_values", "false")
+            .endObject()
+            .startObject("random_int")
+            .field("type", "integer")
+            .field("doc_values", "true")
+            .endObject()
+            .startObject("invalid_random_int")
+            .field("type", "integer")
+            .field("doc_values", "false")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertAcked(
             client().admin()
                 .indices()
                 .prepareCreate("test")
-                .setSettings(Settings.builder().put("number_of_shards", numberOfShards).put("index.max_slices_per_scroll", 10000))
+                .setSettings(
+                    Settings.builder()
+                        .put("number_of_shards", numberOfShards)
+                        .put("index.max_slices_per_scroll", 10000)
+                        .put("index.max_slices_per_pit", 10000)
+                )
                 .setMapping(mapping)
         );
         ensureGreen();
@@ -129,6 +159,78 @@ public void testSearchSort() throws Exception {
         }
     }
 
+    public void testSearchSortWithoutPitOrScroll() throws Exception {
+        int numShards = randomIntBetween(1, 7);
+        int numDocs = randomIntBetween(100, 1000);
+        setupIndex(numDocs, numShards);
+        int fetchSize = randomIntBetween(10, 100);
+        SearchRequestBuilder request = client().prepareSearch("test")
+            .setQuery(matchAllQuery())
+            .setSize(fetchSize)
+            .addSort(SortBuilders.fieldSort("_doc"));
+        SliceBuilder sliceBuilder = new SliceBuilder("_id", 0, 4);
+        SearchPhaseExecutionException ex = expectThrows(SearchPhaseExecutionException.class, () -> request.slice(sliceBuilder).get());
+        assertTrue(ex.getMessage().contains("all shards failed"));
+    }
+
+    public void testSearchSortWithPIT() throws Exception {
+        int numShards = randomIntBetween(1, 7);
+        int numDocs = randomIntBetween(100, 1000);
+        setupIndex(numDocs, numShards);
+        int max = randomIntBetween(2, numShards * 3);
+        CreatePitRequest pitRequest = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        pitRequest.setIndices(new String[] { "test" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, pitRequest);
+        CreatePitResponse pitResponse = execute.get();
+        for (String field : new String[] { "_id", "random_int", "static_int" }) {
+            int fetchSize = randomIntBetween(10, 100);
+
+            // test _doc sort
+            SearchRequestBuilder request = client().prepareSearch("test")
+                .setQuery(matchAllQuery())
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(fetchSize)
+                .addSort(SortBuilders.fieldSort("_doc"));
+            assertSearchSlicesWithPIT(request, field, max, numDocs);
+
+            // test numeric sort
+            request = client().prepareSearch("test")
+                .setQuery(matchAllQuery())
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(fetchSize)
+                .addSort(SortBuilders.fieldSort("random_int"));
+            assertSearchSlicesWithPIT(request, field, max, numDocs);
+        }
+        client().admin().indices().prepareDelete("test").get();
+    }
+
+    private void assertSearchSlicesWithPIT(SearchRequestBuilder request, String field, int numSlice, int numDocs) {
+        int totalResults = 0;
+        List<String> keys = new ArrayList<>();
+        for (int id = 0; id < numSlice; id++) {
+            SliceBuilder sliceBuilder = new SliceBuilder(field, id, numSlice);
+            SearchResponse searchResponse = request.slice(sliceBuilder).setFrom(0).get();
+            totalResults += searchResponse.getHits().getHits().length;
+            int expectedSliceResults = (int) searchResponse.getHits().getTotalHits().value;
+            int numSliceResults = searchResponse.getHits().getHits().length;
+            for (SearchHit hit : searchResponse.getHits().getHits()) {
+                assertTrue(keys.add(hit.getId()));
+            }
+            while (searchResponse.getHits().getHits().length > 0) {
+                searchResponse = request.setFrom(numSliceResults).slice(sliceBuilder).get();
+                totalResults += searchResponse.getHits().getHits().length;
+                numSliceResults += searchResponse.getHits().getHits().length;
+                for (SearchHit hit : searchResponse.getHits().getHits()) {
+                    assertTrue(keys.add(hit.getId()));
+                }
+            }
+            assertThat(numSliceResults, equalTo(expectedSliceResults));
+        }
+        assertThat(totalResults, equalTo(numDocs));
+        assertThat(keys.size(), equalTo(numDocs));
+        assertThat(new HashSet(keys).size(), equalTo(numDocs));
+    }
+
     public void testWithPreferenceAndRoutings() throws Exception {
         int numShards = 10;
         int totalDocs = randomIntBetween(100, 1000);
@@ -217,7 +319,7 @@ public void testInvalidQuery() throws Exception {
         );
         Throwable rootCause = findRootCause(exc);
         assertThat(rootCause.getClass(), equalTo(SearchException.class));
-        assertThat(rootCause.getMessage(), equalTo("`slice` cannot be used outside of a scroll context"));
+        assertThat(rootCause.getMessage(), equalTo("`slice` cannot be used outside of a scroll context or PIT context"));
     }
 
     private void assertSearchSlicesWithScroll(SearchRequestBuilder request, String field, int numSlice, int numDocs) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/sort/FieldSortIT.java b/server/src/internalClusterTest/java/org/opensearch/search/sort/FieldSortIT.java
index 4bf4cd138cbd1..bee242b933dfd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/sort/FieldSortIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/sort/FieldSortIT.java
@@ -32,10 +32,11 @@
 
 package org.opensearch.search.sort;
 
-import org.apache.lucene.util.BytesRef;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.UnicodeUtil;
-
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.bulk.BulkRequestBuilder;
@@ -44,27 +45,29 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.functionscore.ScoreFunctionBuilders;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -86,6 +89,7 @@
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.functionscore.ScoreFunctionBuilders.fieldValueFactorFunction;
 import static org.opensearch.script.MockScriptPlugin.NAME;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -103,8 +107,26 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.Matchers.oneOf;
+
+public class FieldSortIT extends ParameterizedOpenSearchIntegTestCase {
+    public FieldSortIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
-public class FieldSortIT extends OpenSearchIntegTestCase {
     public static class CustomScriptPlugin extends MockScriptPlugin {
         @Override
         protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
@@ -142,7 +164,7 @@ public void testIssue8226() {
                 assertAcked(prepareCreate("test_" + i).addAlias(new Alias("test")));
             }
             if (i > 0) {
-                client().prepareIndex("test_" + i).setId("" + i).setSource("{\"entry\": " + i + "}", XContentType.JSON).get();
+                client().prepareIndex("test_" + i).setId("" + i).setSource("{\"entry\": " + i + "}", MediaTypeRegistry.JSON).get();
             }
         }
         refresh();
@@ -494,9 +516,9 @@ public void testScoreSortDirectionWithFunctionScore() throws Exception {
     public void testIssue2986() {
         assertAcked(client().admin().indices().prepareCreate("test").setMapping("field1", "type=keyword").get());
 
-        client().prepareIndex("test").setId("1").setSource("{\"field1\":\"value1\"}", XContentType.JSON).get();
-        client().prepareIndex("test").setId("2").setSource("{\"field1\":\"value2\"}", XContentType.JSON).get();
-        client().prepareIndex("test").setId("3").setSource("{\"field1\":\"value3\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"field1\":\"value1\"}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex("test").setId("2").setSource("{\"field1\":\"value2\"}", MediaTypeRegistry.JSON).get();
+        client().prepareIndex("test").setId("3").setSource("{\"field1\":\"value3\"}", MediaTypeRegistry.JSON).get();
         refresh();
         SearchResponse result = client().prepareSearch("test")
             .setQuery(matchAllQuery())
@@ -577,6 +599,9 @@ public void testSimpleSorts() throws Exception {
                     .startObject("long_value")
                     .field("type", "long")
                     .endObject()
+                    .startObject("unsigned_long_value")
+                    .field("type", "unsigned_long")
+                    .endObject()
                     .startObject("float_value")
                     .field("type", "float")
                     .endObject()
@@ -588,6 +613,7 @@ public void testSimpleSorts() throws Exception {
             )
         );
         ensureGreen();
+        BigInteger UNSIGNED_LONG_BASE = Numbers.MAX_UNSIGNED_LONG_VALUE.subtract(BigInteger.valueOf(100000));
         List<IndexRequestBuilder> builders = new ArrayList<>();
         for (int i = 0; i < 10; i++) {
             IndexRequestBuilder builder = client().prepareIndex("test")
@@ -600,6 +626,7 @@ public void testSimpleSorts() throws Exception {
                         .field("short_value", i)
                         .field("integer_value", i)
                         .field("long_value", i)
+                        .field("unsigned_long_value", UNSIGNED_LONG_BASE.add(BigInteger.valueOf(10000 * i)))
                         .field("float_value", 0.1 * i)
                         .field("double_value", 0.1 * i)
                         .endObject()
@@ -622,7 +649,6 @@ public void testSimpleSorts() throws Exception {
 
         // STRING
         int size = 1 + random.nextInt(10);
-
         SearchResponse searchResponse = client().prepareSearch()
             .setQuery(matchAllQuery())
             .setSize(size)
@@ -791,6 +817,45 @@ public void testSimpleSorts() throws Exception {
         }
 
         assertNoFailures(searchResponse);
+
+        // UNSIGNED_LONG
+        size = 1 + random.nextInt(10);
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .setSize(size)
+            .addSort("unsigned_long_value", SortOrder.ASC)
+            .get();
+
+        assertHitCount(searchResponse, 10);
+        assertThat(searchResponse.getHits().getHits().length, equalTo(size));
+        for (int i = 0; i < size; i++) {
+            assertThat(searchResponse.getHits().getAt(i).getId(), equalTo(Integer.toString(i)));
+            assertThat(
+                ((Number) searchResponse.getHits().getAt(i).getSortValues()[0]),
+                equalTo(UNSIGNED_LONG_BASE.add(BigInteger.valueOf(10000 * i)))
+            );
+        }
+
+        assertThat(searchResponse.toString(), not(containsString("error")));
+        size = 1 + random.nextInt(10);
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .setSize(size)
+            .addSort("unsigned_long_value", SortOrder.DESC)
+            .get();
+        assertHitCount(searchResponse, 10L);
+        assertHitCount(searchResponse, 10);
+        assertThat(searchResponse.getHits().getHits().length, equalTo(size));
+        for (int i = 0; i < size; i++) {
+            assertThat(searchResponse.getHits().getAt(i).getId(), equalTo(Integer.toString(9 - i)));
+            assertThat(
+                ((Number) searchResponse.getHits().getAt(i).getSortValues()[0]),
+                equalTo(UNSIGNED_LONG_BASE.add(BigInteger.valueOf(10000 * (9 - i))))
+            );
+        }
+
+        assertThat(searchResponse.toString(), not(containsString("error")));
+        assertNoFailures(searchResponse);
     }
 
     public void testSortMissingNumbers() throws Exception {
@@ -805,6 +870,9 @@ public void testSortMissingNumbers() throws Exception {
                     .startObject("d_value")
                     .field("type", "float")
                     .endObject()
+                    .startObject("u_value")
+                    .field("type", "unsigned_long")
+                    .endObject()
                     .endObject()
                     .endObject()
             )
@@ -812,19 +880,24 @@ public void testSortMissingNumbers() throws Exception {
         ensureGreen();
         client().prepareIndex("test")
             .setId("1")
-            .setSource(jsonBuilder().startObject().field("id", "1").field("i_value", -1).field("d_value", -1.1).endObject())
+            .setSource(
+                jsonBuilder().startObject().field("id", "1").field("i_value", -1).field("d_value", -1.1).field("u_value", 1).endObject()
+            )
             .get();
 
         client().prepareIndex("test").setId("2").setSource(jsonBuilder().startObject().field("id", "2").endObject()).get();
 
         client().prepareIndex("test")
             .setId("3")
-            .setSource(jsonBuilder().startObject().field("id", "1").field("i_value", 2).field("d_value", 2.2).endObject())
+            .setSource(
+                jsonBuilder().startObject().field("id", "3").field("i_value", 2).field("d_value", 2.2).field("u_value", 2).endObject()
+            )
             .get();
 
         flush();
         refresh();
 
+        // DOUBLE
         logger.info("--> sort with no missing (same as missing _last)");
         SearchResponse searchResponse = client().prepareSearch()
             .setQuery(matchAllQuery())
@@ -860,6 +933,247 @@ public void testSortMissingNumbers() throws Exception {
         assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("2"));
         assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("1"));
         assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
+
+        // FLOAT
+        logger.info("--> sort with no missing (same as missing _last)");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _last");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC).missing("_last"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _first");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC).missing("_first"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("2"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
+
+        // UNSIGNED_LONG
+        logger.info("--> sort with no missing (same as missing _last)");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _last");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC).missing("_last"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _first");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC).missing("_first"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("2"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
+    }
+
+    public void testSortMissingNumbersMinMax() throws Exception {
+        assertAcked(
+            prepareCreate("test").setMapping(
+                XContentFactory.jsonBuilder()
+                    .startObject()
+                    .startObject("properties")
+                    .startObject("l_value")
+                    .field("type", "long")
+                    .endObject()
+                    .startObject("d_value")
+                    .field("type", "float")
+                    .endObject()
+                    .startObject("u_value")
+                    .field("type", "unsigned_long")
+                    .endObject()
+                    .endObject()
+                    .endObject()
+            )
+        );
+        ensureGreen();
+        client().prepareIndex("test")
+            .setId("1")
+            .setSource(
+                jsonBuilder().startObject()
+                    .field("id", "1")
+                    .field("l_value", Long.MIN_VALUE)
+                    .field("d_value", Float.MIN_VALUE)
+                    .field("u_value", Numbers.MIN_UNSIGNED_LONG_VALUE)
+                    .endObject()
+            )
+            .get();
+
+        client().prepareIndex("test").setId("2").setSource(jsonBuilder().startObject().field("id", "2").endObject()).get();
+
+        client().prepareIndex("test")
+            .setId("3")
+            .setSource(
+                jsonBuilder().startObject()
+                    .field("id", "3")
+                    .field("l_value", Long.MAX_VALUE)
+                    .field("d_value", Float.MAX_VALUE)
+                    .field("u_value", Numbers.MAX_UNSIGNED_LONG_VALUE)
+                    .endObject()
+            )
+            .get();
+
+        flush();
+        refresh();
+
+        // LONG
+        logger.info("--> sort with no missing (same as missing _last)");
+        SearchResponse searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("l_value").order(SortOrder.ASC))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("3", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), is(oneOf("2", "3")));
+
+        logger.info("--> sort with missing _last");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("l_value").order(SortOrder.ASC).missing("_last"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("3", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), is(oneOf("2", "3")));
+
+        logger.info("--> sort with missing _first");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("l_value").order(SortOrder.ASC).missing("_first"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(0).getId(), is(oneOf("2", "1")));
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("1", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
+
+        // FLOAT
+        logger.info("--> sort with no missing (same as missing _last)");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _last");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC).missing("_last"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("3"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("2"));
+
+        logger.info("--> sort with missing _first");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("d_value").order(SortOrder.ASC).missing("_first"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("2"));
+        assertThat(searchResponse.getHits().getAt(1).getId(), equalTo("1"));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
+
+        // UNSIGNED_LONG
+        logger.info("--> sort with no missing (same as missing _last)");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("3", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), is(oneOf("2", "3")));
+
+        logger.info("--> sort with missing _last");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC).missing("_last"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        assertThat(searchResponse.getHits().getAt(0).getId(), equalTo("1"));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("3", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), is(oneOf("2", "3")));
+
+        logger.info("--> sort with missing _first");
+        searchResponse = client().prepareSearch()
+            .setQuery(matchAllQuery())
+            .addSort(SortBuilders.fieldSort("u_value").order(SortOrder.ASC).missing("_first"))
+            .get();
+        assertNoFailures(searchResponse);
+
+        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(3L));
+        // The order here could be unstable (depends on document order) since missing == field value
+        assertThat(searchResponse.getHits().getAt(0).getId(), is(oneOf("2", "1")));
+        assertThat(searchResponse.getHits().getAt(1).getId(), is(oneOf("1", "2")));
+        assertThat(searchResponse.getHits().getAt(2).getId(), equalTo("3"));
     }
 
     public void testSortMissingStrings() throws IOException {
@@ -1964,7 +2278,7 @@ public void testLongSortOptimizationCorrectResults() {
                 bulkBuilder = client().prepareBulk();
             }
             String source = "{\"long_field\":" + randomLong() + "}";
-            bulkBuilder.add(client().prepareIndex("test1").setId(Integer.toString(i)).setSource(source, XContentType.JSON));
+            bulkBuilder.add(client().prepareIndex("test1").setId(Integer.toString(i)).setSource(source, MediaTypeRegistry.JSON));
         }
         refresh();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceIT.java b/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceIT.java
index 5cc9ab77bcb2d..6886f8d67589e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceIT.java
@@ -32,24 +32,30 @@
 
 package org.opensearch.search.sort;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.Version;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFirstHit;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -60,7 +66,24 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 
-public class GeoDistanceIT extends OpenSearchIntegTestCase {
+public class GeoDistanceIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public GeoDistanceIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected boolean forbidPrivateIndexSettings() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceSortBuilderIT.java b/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceSortBuilderIT.java
index aebd83592e793..7880fc24fd846 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceSortBuilderIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceSortBuilderIT.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.sort;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.Version;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -39,28 +41,47 @@
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.GeoValidationMethod;
 import org.opensearch.search.builder.SearchSourceBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.sort.SortBuilders.fieldSort;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertOrderedSearchHits;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSortValues;
 import static org.hamcrest.Matchers.closeTo;
 
-public class GeoDistanceSortBuilderIT extends OpenSearchIntegTestCase {
+public class GeoDistanceSortBuilderIT extends ParameterizedOpenSearchIntegTestCase {
+    public GeoDistanceSortBuilderIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     private static final String LOCATION_FIELD = "location";
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/sort/SimpleSortIT.java b/server/src/internalClusterTest/java/org/opensearch/search/sort/SimpleSortIT.java
index 8ff0790e7cb48..ddfbc3cce2be6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/sort/SimpleSortIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/sort/SimpleSortIT.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.search.sort;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptPlugin;
@@ -45,8 +48,8 @@
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.sort.ScriptSortBuilder.ScriptSortType;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -62,6 +65,7 @@
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.sort.SortBuilders.scriptSort;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -71,10 +75,27 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
 
-public class SimpleSortIT extends OpenSearchIntegTestCase {
+public class SimpleSortIT extends ParameterizedOpenSearchIntegTestCase {
 
     private static final String DOUBLE_APOSTROPHE = "\u0027\u0027";
 
+    public SimpleSortIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(CustomScriptPlugin.class, InternalSettingsPlugin.class);
@@ -237,24 +258,23 @@ public void testSimpleSorts() throws Exception {
     }
 
     public void testSortMinValueScript() throws IOException {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("lvalue")
-                .field("type", "long")
-                .endObject()
-                .startObject("dvalue")
-                .field("type", "double")
-                .endObject()
-                .startObject("svalue")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("gvalue")
-                .field("type", "geo_point")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("lvalue")
+            .field("type", "long")
+            .endObject()
+            .startObject("dvalue")
+            .field("type", "double")
+            .endObject()
+            .startObject("svalue")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("gvalue")
+            .field("type", "geo_point")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertAcked(prepareCreate("test").setMapping(mapping));
         ensureGreen();
@@ -351,18 +371,17 @@ public void testDocumentsWithNullValue() throws Exception {
         // TODO: sort shouldn't fail when sort field is mapped dynamically
         // We have to specify mapping explicitly because by the time search is performed dynamic mapping might not
         // be propagated to all nodes yet and sort operation fail when the sort field is not defined
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("id")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("svalue")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("id")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("svalue")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertAcked(prepareCreate("test").setMapping(mapping));
         ensureGreen();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/sort/SortFromPluginIT.java b/server/src/internalClusterTest/java/org/opensearch/search/sort/SortFromPluginIT.java
index e9fc1c54ad234..7bcded86fcaa8 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/sort/SortFromPluginIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/sort/SortFromPluginIT.java
@@ -8,21 +8,42 @@
 
 package org.opensearch.search.sort;
 
-import static org.hamcrest.Matchers.equalTo;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.sort.plugin.CustomSortBuilder;
 import org.opensearch.search.sort.plugin.CustomSortPlugin;
 import org.opensearch.test.InternalSettingsPlugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
 
-public class SortFromPluginIT extends OpenSearchIntegTestCase {
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+import static org.hamcrest.Matchers.equalTo;
+
+public class SortFromPluginIT extends ParameterizedOpenSearchIntegTestCase {
+    public SortFromPluginIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/source/MetadataFetchingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/source/MetadataFetchingIT.java
index 4f6dd89285bee..c98a38ea0bb97 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/source/MetadataFetchingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/source/MetadataFetchingIT.java
@@ -31,26 +31,51 @@
 
 package org.opensearch.search.source;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.NestedQueryBuilder;
 import org.opensearch.index.query.TermQueryBuilder;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 
-public class MetadataFetchingIT extends OpenSearchIntegTestCase {
+public class MetadataFetchingIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public MetadataFetchingIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testSimple() {
         assertAcked(prepareCreate("test"));
         ensureGreen();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/source/SourceFetchingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/source/SourceFetchingIT.java
index 11223d11ff30d..eeef5403fe898 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/source/SourceFetchingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/source/SourceFetchingIT.java
@@ -32,14 +32,40 @@
 
 package org.opensearch.search.source;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.core.IsEqual.equalTo;
 
-public class SourceFetchingIT extends OpenSearchIntegTestCase {
+public class SourceFetchingIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SourceFetchingIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testSourceDefaultBehavior() {
         createIndex("test");
         ensureGreen();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/stats/ConcurrentSearchStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/stats/ConcurrentSearchStatsIT.java
new file mode 100644
index 0000000000000..abfd39793f1a4
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/search/stats/ConcurrentSearchStatsIT.java
@@ -0,0 +1,364 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.stats;
+
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsAction;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequestBuilder;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.action.admin.indices.stats.IndexStats;
+import org.opensearch.action.admin.indices.stats.IndicesStatsRequestBuilder;
+import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.indices.IndicesQueryCache;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.script.MockScriptPlugin;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptType;
+import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.threadpool.ThreadPoolStats;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Locale;
+import java.util.Map;
+import java.util.function.Function;
+
+import static org.opensearch.index.query.QueryBuilders.scriptQuery;
+import static org.opensearch.search.SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.lessThan;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 1, numClientNodes = 0, supportsDedicatedMasters = false)
+public class ConcurrentSearchStatsIT extends OpenSearchIntegTestCase {
+
+    private final int SEGMENT_SLICE_COUNT = 4;
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return Arrays.asList(ScriptedDelayedPlugin.class, InternalSettingsPlugin.class);
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        // Filter/Query cache is cleaned periodically, default is 60s, so make sure it runs often. Thread.sleep for 60s is bad
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(IndicesService.INDICES_CACHE_CLEAN_INTERVAL_SETTING.getKey(), "1ms")
+            .put(IndicesQueryCache.INDICES_QUERIES_CACHE_ALL_SEGMENTS_SETTING.getKey(), true)
+            .put(CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY, SEGMENT_SLICE_COUNT)
+            .build();
+    }
+
+    @Override
+    public Settings indexSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexModule.INDEX_QUERY_CACHE_EVERYTHING_SETTING.getKey(), false)
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexSettings.INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING.getKey(), 0)
+            .build();
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
+    public void testConcurrentQueryCount() throws Exception {
+        String INDEX_1 = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        String INDEX_2 = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        int NUM_SHARDS = randomIntBetween(1, 5);
+        createIndex(
+            INDEX_1,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+        createIndex(
+            INDEX_2,
+            Settings.builder()
+                .put(indexSettings())
+                .put("search.concurrent_segment_search.enabled", false)
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+
+        ensureGreen();
+
+        indexRandom(
+            false,
+            true,
+            client().prepareIndex(INDEX_1).setId("1").setSource("foo", "bar"),
+            client().prepareIndex(INDEX_1).setId("2").setSource("foo", "baz"),
+            client().prepareIndex(INDEX_2).setId("1").setSource("foo", "bar"),
+            client().prepareIndex(INDEX_2).setId("2").setSource("foo", "baz")
+        );
+
+        refresh();
+
+        // Search with custom plugin to ensure that queryTime is significant
+        client().prepareSearch(INDEX_1, INDEX_2)
+            .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedDelayedPlugin.SCRIPT_NAME, Collections.emptyMap())))
+            .execute()
+            .actionGet();
+        client().prepareSearch(INDEX_1)
+            .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedDelayedPlugin.SCRIPT_NAME, Collections.emptyMap())))
+            .execute()
+            .actionGet();
+        client().prepareSearch(INDEX_2)
+            .setQuery(scriptQuery(new Script(ScriptType.INLINE, "mockscript", ScriptedDelayedPlugin.SCRIPT_NAME, Collections.emptyMap())))
+            .execute()
+            .actionGet();
+
+        IndicesStatsRequestBuilder builder = client().admin().indices().prepareStats();
+        IndicesStatsResponse stats = builder.execute().actionGet();
+
+        assertEquals(4 * NUM_SHARDS, stats.getTotal().search.getTotal().getQueryCount());
+        assertEquals(2 * NUM_SHARDS, stats.getTotal().search.getTotal().getConcurrentQueryCount());
+        assertThat(stats.getTotal().search.getTotal().getQueryTimeInMillis(), greaterThan(0L));
+        assertThat(stats.getTotal().search.getTotal().getConcurrentQueryTimeInMillis(), greaterThan(0L));
+        assertThat(
+            stats.getTotal().search.getTotal().getConcurrentQueryTimeInMillis(),
+            lessThan(stats.getTotal().search.getTotal().getQueryTimeInMillis())
+        );
+    }
+
+    /**
+     * Test average concurrency is correctly calculated across indices for the same node
+     */
+    public void testAvgConcurrencyNodeLevel() throws InterruptedException {
+        int NUM_SHARDS = 1;
+        String INDEX_1 = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        String INDEX_2 = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+
+        // Create index test1 with 4 segments
+        createIndex(
+            INDEX_1,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+        ensureGreen();
+        for (int i = 0; i < 4; i++) {
+            client().prepareIndex(INDEX_1).setId(Integer.toString(i)).setSource("field", "value" + i).get();
+            refresh();
+        }
+
+        client().prepareSearch(INDEX_1).execute().actionGet();
+        NodesStatsResponse nodesStatsResponse = client().admin().cluster().prepareNodesStats().execute().actionGet();
+
+        assertEquals(1, nodesStatsResponse.getNodes().size(), 0);
+        double expectedConcurrency = SEGMENT_SLICE_COUNT;
+        assertEquals(
+            SEGMENT_SLICE_COUNT,
+            nodesStatsResponse.getNodes().get(0).getIndices().getSearch().getTotal().getConcurrentAvgSliceCount(),
+            0
+        );
+
+        forceMerge();
+        // Sleep to make sure force merge completes
+        Thread.sleep(1000);
+        client().prepareSearch(INDEX_1).execute().actionGet();
+
+        nodesStatsResponse = client().admin().cluster().prepareNodesStats().execute().actionGet();
+
+        assertEquals(1, nodesStatsResponse.getNodes().size(), 0);
+        expectedConcurrency = (SEGMENT_SLICE_COUNT + 1) / 2.0;
+        assertEquals(
+            expectedConcurrency,
+            nodesStatsResponse.getNodes().get(0).getIndices().getSearch().getTotal().getConcurrentAvgSliceCount(),
+            0
+        );
+
+        // Create second index test2 with 4 segments
+        createIndex(
+            INDEX_2,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+        ensureGreen();
+        for (int i = 0; i < 4; i++) {
+            client().prepareIndex(INDEX_2).setId(Integer.toString(i)).setSource("field", "value" + i).get();
+            refresh();
+        }
+
+        client().prepareSearch(INDEX_2).execute().actionGet();
+        nodesStatsResponse = client().admin().cluster().prepareNodesStats().execute().actionGet();
+
+        assertEquals(1, nodesStatsResponse.getNodes().size(), 0);
+        expectedConcurrency = (SEGMENT_SLICE_COUNT + 1 + SEGMENT_SLICE_COUNT) / 3.0;
+        assertEquals(
+            expectedConcurrency,
+            nodesStatsResponse.getNodes().get(0).getIndices().getSearch().getTotal().getConcurrentAvgSliceCount(),
+            0
+        );
+
+        forceMerge();
+        // Sleep to make sure force merge completes
+        Thread.sleep(1000);
+        client().prepareSearch(INDEX_2).execute().actionGet();
+        nodesStatsResponse = client().admin().cluster().prepareNodesStats().execute().actionGet();
+
+        assertEquals(1, nodesStatsResponse.getNodes().size(), 0);
+        expectedConcurrency = (SEGMENT_SLICE_COUNT + 1 + SEGMENT_SLICE_COUNT + 1) / 4.0;
+        assertEquals(
+            expectedConcurrency,
+            nodesStatsResponse.getNodes().get(0).getIndices().getSearch().getTotal().getConcurrentAvgSliceCount(),
+            0
+        );
+
+        // Check that non-concurrent search requests do not affect the average concurrency
+        client().admin()
+            .indices()
+            .prepareUpdateSettings(INDEX_1)
+            .setSettings(Settings.builder().put("search.concurrent_segment_search.enabled", false))
+            .execute()
+            .actionGet();
+        client().admin()
+            .indices()
+            .prepareUpdateSettings(INDEX_2)
+            .setSettings(Settings.builder().put("search.concurrent_segment_search.enabled", false))
+            .execute()
+            .actionGet();
+        client().prepareSearch(INDEX_1).execute().actionGet();
+        client().prepareSearch(INDEX_2).execute().actionGet();
+        assertEquals(1, nodesStatsResponse.getNodes().size(), 0);
+        assertEquals(
+            expectedConcurrency,
+            nodesStatsResponse.getNodes().get(0).getIndices().getSearch().getTotal().getConcurrentAvgSliceCount(),
+            0
+        );
+    }
+
+    /**
+     * Test average concurrency is correctly calculated across shard for the same index
+     */
+    public void testAvgConcurrencyIndexLevel() throws InterruptedException {
+        int NUM_SHARDS = 2;
+        String INDEX = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        createIndex(
+            INDEX,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+        ensureGreen();
+        // Create 4 segments on each shard
+        for (int i = 0; i < 4; i++) {
+            client().prepareIndex(INDEX).setId(Integer.toString(i)).setSource("field", "value" + i).setRouting("0").get();
+            refresh();
+        }
+        for (int i = 4; i < 8; i++) {
+            client().prepareIndex(INDEX).setId(Integer.toString(i)).setSource("field", "value" + i).setRouting("1").get();
+            refresh();
+        }
+        client().prepareSearch(INDEX).execute().actionGet();
+        IndicesStatsResponse indicesStatsResponse = client().admin().indices().prepareStats().execute().actionGet();
+
+        IndexStats stats = indicesStatsResponse.getIndices().get(INDEX);
+        assertNotNull(stats);
+        double expectedConcurrency = (SEGMENT_SLICE_COUNT * NUM_SHARDS) / (double) NUM_SHARDS;
+        assertEquals(expectedConcurrency, stats.getTotal().getSearch().getTotal().getConcurrentAvgSliceCount(), 0);
+
+        forceMerge();
+        // Sleep to make sure force merge completes
+        Thread.sleep(1000);
+        client().prepareSearch(INDEX).execute().actionGet();
+
+        indicesStatsResponse = client().admin().indices().prepareStats().execute().actionGet();
+        stats = indicesStatsResponse.getIndices().get(INDEX);
+        assertNotNull(stats);
+        expectedConcurrency = (SEGMENT_SLICE_COUNT * NUM_SHARDS + 1 * NUM_SHARDS) / (NUM_SHARDS * 2.0);
+        assertEquals(expectedConcurrency, stats.getTotal().getSearch().getTotal().getConcurrentAvgSliceCount(), 0);
+
+        // Check that non-concurrent search requests do not affect the average concurrency
+        client().admin()
+            .indices()
+            .prepareUpdateSettings(INDEX)
+            .setSettings(Settings.builder().put("search.concurrent_segment_search.enabled", false))
+            .execute()
+            .actionGet();
+
+        client().prepareSearch(INDEX).execute().actionGet();
+
+        indicesStatsResponse = client().admin().indices().prepareStats().execute().actionGet();
+        stats = indicesStatsResponse.getIndices().get(INDEX);
+        assertNotNull(stats);
+        assertEquals(expectedConcurrency, stats.getTotal().getSearch().getTotal().getConcurrentAvgSliceCount(), 0);
+    }
+
+    public void testThreadPoolWaitTime() throws Exception {
+        int NUM_SHARDS = 1;
+        String INDEX = "test-" + randomAlphaOfLength(5).toLowerCase(Locale.ROOT);
+        createIndex(
+            INDEX,
+            Settings.builder()
+                .put(indexSettings())
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, NUM_SHARDS)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+                .build()
+        );
+
+        ensureGreen();
+
+        for (int i = 0; i < 10; i++) {
+            client().prepareIndex(INDEX).setId(Integer.toString(i)).setSource("field", "value" + i).get();
+            refresh();
+        }
+
+        client().prepareSearch(INDEX).execute().actionGet();
+
+        NodesStatsRequestBuilder nodesStatsRequestBuilder = new NodesStatsRequestBuilder(
+            client().admin().cluster(),
+            NodesStatsAction.INSTANCE
+        ).setNodesIds().all();
+        NodesStatsResponse nodesStatsResponse = nodesStatsRequestBuilder.execute().actionGet();
+        ThreadPoolStats threadPoolStats = nodesStatsResponse.getNodes().get(0).getThreadPool();
+
+        for (ThreadPoolStats.Stats stats : threadPoolStats) {
+            if (stats.getName().equals(ThreadPool.Names.INDEX_SEARCHER)) {
+                assertThat(stats.getWaitTime().nanos(), greaterThan(0L));
+            }
+        }
+    }
+
+    public static class ScriptedDelayedPlugin extends MockScriptPlugin {
+        static final String SCRIPT_NAME = "search_timeout";
+
+        @Override
+        public Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
+            return Collections.singletonMap(SCRIPT_NAME, params -> {
+                try {
+                    Thread.sleep(500);
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                return true;
+            });
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/stats/SearchStatsIT.java b/server/src/internalClusterTest/java/org/opensearch/search/stats/SearchStatsIT.java
index c72b5d40553b3..253a8b2b14824 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/stats/SearchStatsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/stats/SearchStatsIT.java
@@ -32,9 +32,12 @@
 
 package org.opensearch.search.stats;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
+import org.opensearch.action.search.SearchPhaseName;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.GroupShardsIterator;
@@ -42,6 +45,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.search.stats.SearchStats.Stats;
 import org.opensearch.plugins.Plugin;
@@ -50,7 +54,9 @@
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -58,9 +64,11 @@
 import java.util.Set;
 import java.util.function.Function;
 
+import static org.opensearch.action.search.TransportSearchAction.SEARCH_REQUEST_STATS_ENABLED_KEY;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -72,8 +80,25 @@
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 
-@OpenSearchIntegTestCase.ClusterScope(minNumDataNodes = 2)
-public class SearchStatsIT extends OpenSearchIntegTestCase {
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, minNumDataNodes = 2)
+public class SearchStatsIT extends ParameterizedOpenSearchIntegTestCase {
+
+    public SearchStatsIT(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
@@ -103,6 +128,11 @@ public void testSimpleStats() throws Exception {
         assertThat(numNodes, greaterThanOrEqualTo(2));
         final int shardsIdx1 = randomIntBetween(1, 10); // we make sure each node gets at least a single shard...
         final int shardsIdx2 = Math.max(numNodes - shardsIdx1, randomIntBetween(1, 10));
+        client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setPersistentSettings(Settings.builder().put(SEARCH_REQUEST_STATS_ENABLED_KEY, true).build())
+            .get();
         assertThat(numNodes, lessThanOrEqualTo(shardsIdx1 + shardsIdx2));
         assertAcked(
             prepareCreate("test1").setSettings(
@@ -165,20 +195,40 @@ public void testSimpleStats() throws Exception {
 
         Set<String> nodeIdsWithIndex = nodeIdsWithIndex("test1", "test2");
         int num = 0;
+        int numOfCoordinators = 0;
+
         for (NodeStats stat : nodeStats.getNodes()) {
             Stats total = stat.getIndices().getSearch().getTotal();
+            if (total.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.QUERY.getName()).getTimeInMillis() > 0) {
+                assertThat(
+                    total.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.FETCH.getName()).getTimeInMillis(),
+                    greaterThan(0L)
+                );
+                assertEquals(
+                    iters,
+                    total.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.FETCH.getName()).getTotal()
+                );
+                assertEquals(
+                    iters,
+                    total.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.EXPAND.getName()).getTotal()
+                );
+                assertEquals(
+                    iters,
+                    total.getRequestStatsLongHolder().getRequestStatsHolder().get(SearchPhaseName.FETCH.getName()).getTotal()
+                );
+                numOfCoordinators += 1;
+            }
             if (nodeIdsWithIndex.contains(stat.getNode().getId())) {
                 assertThat(total.getQueryCount(), greaterThan(0L));
                 assertThat(total.getQueryTimeInMillis(), greaterThan(0L));
                 num++;
             } else {
-                assertThat(total.getQueryCount(), equalTo(0L));
+                assertThat(total.getQueryCount(), greaterThanOrEqualTo(0L));
                 assertThat(total.getQueryTimeInMillis(), equalTo(0L));
             }
         }
-
+        assertThat(numOfCoordinators, greaterThan(0));
         assertThat(num, greaterThan(0));
-
     }
 
     private Set<String> nodeIdsWithIndex(String... indices) {
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/suggest/CompletionSuggestSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/suggest/CompletionSuggestSearchIT.java
index 690564fe1cac8..30dba87f8ef5d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/suggest/CompletionSuggestSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/suggest/CompletionSuggestSearchIT.java
@@ -31,7 +31,9 @@
 
 package org.opensearch.search.suggest;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.lucene.analysis.TokenStreamToAutomaton;
 import org.apache.lucene.search.suggest.document.ContextSuggestField;
 import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
@@ -46,8 +48,9 @@
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.plugins.Plugin;
@@ -61,8 +64,8 @@
 import org.opensearch.search.suggest.completion.context.CategoryContextMapping;
 import org.opensearch.search.suggest.completion.context.ContextMapping;
 import org.opensearch.search.suggest.completion.context.GeoContextMapping;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -78,8 +81,9 @@
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
-import static org.opensearch.common.util.CollectionUtils.iterableAsArrayList;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.core.common.util.CollectionUtils.iterableAsArrayList;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.hasId;
@@ -95,7 +99,24 @@
 import static org.hamcrest.Matchers.notNullValue;
 
 @SuppressCodecs("*") // requires custom completion format
-public class CompletionSuggestSearchIT extends OpenSearchIntegTestCase {
+public class CompletionSuggestSearchIT extends ParameterizedOpenSearchIntegTestCase {
+    public CompletionSuggestSearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     private final String INDEX = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
     private final String FIELD = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
     private final CompletionMappingBuilder completionMappingBuilder = new CompletionMappingBuilder();
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/suggest/ContextCompletionSuggestSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/suggest/ContextCompletionSuggestSearchIT.java
index 27d3d455330f5..bac3e7fb61683 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/suggest/ContextCompletionSuggestSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/suggest/ContextCompletionSuggestSearchIT.java
@@ -31,18 +31,20 @@
 
 package org.opensearch.search.suggest;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
-import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
 
+import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.suggest.CompletionSuggestSearchIT.CompletionMappingBuilder;
 import org.opensearch.search.suggest.completion.CompletionSuggestionBuilder;
 import org.opensearch.search.suggest.completion.context.CategoryContextMapping;
@@ -51,11 +53,12 @@
 import org.opensearch.search.suggest.completion.context.ContextMapping;
 import org.opensearch.search.suggest.completion.context.GeoContextMapping;
 import org.opensearch.search.suggest.completion.context.GeoQueryContext;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -64,12 +67,29 @@
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertNoFailures;
 import static org.hamcrest.core.IsEqual.equalTo;
 
 @SuppressCodecs("*") // requires custom completion format
-public class ContextCompletionSuggestSearchIT extends OpenSearchIntegTestCase {
+public class ContextCompletionSuggestSearchIT extends ParameterizedOpenSearchIntegTestCase {
+    public ContextCompletionSuggestSearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     private final String INDEX = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
     private final String FIELD = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/suggest/SuggestSearchIT.java b/server/src/internalClusterTest/java/org/opensearch/search/suggest/SuggestSearchIT.java
index 07e58db836740..32bb0e34054bb 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/suggest/SuggestSearchIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/suggest/SuggestSearchIT.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.search.suggest;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.ScriptPlugin;
@@ -55,7 +57,7 @@
 import org.opensearch.search.suggest.phrase.StupidBackoff;
 import org.opensearch.search.suggest.term.TermSuggestionBuilder;
 import org.opensearch.search.suggest.term.TermSuggestionBuilder.SuggestMode;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
 import java.io.IOException;
@@ -74,6 +76,7 @@
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.suggest.SuggestBuilders.phraseSuggestion;
 import static org.opensearch.search.suggest.SuggestBuilders.termSuggestion;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -93,7 +96,23 @@
  * possible these tests should declare for the first request, make the request, modify the configuration for the next request, make that
  * request, modify again, request again, etc.  This makes it very obvious what changes between requests.
  */
-public class SuggestSearchIT extends OpenSearchIntegTestCase {
+public class SuggestSearchIT extends ParameterizedOpenSearchIntegTestCase {
+    public SuggestSearchIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     // see #3196
     public void testSuggestAcrossMultipleIndices() throws IOException {
@@ -1305,14 +1324,13 @@ public void testPhraseSuggesterCollate() throws InterruptedException, ExecutionE
         assertSuggestionSize(searchSuggest, 0, 10, "title");
 
         // suggest with collate
-        String filterString = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("match_phrase")
-                .field("{{field}}", "{{suggestion}}")
-                .endObject()
-                .endObject()
-        );
+        String filterString = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("match_phrase")
+            .field("{{field}}", "{{suggestion}}")
+            .endObject()
+            .endObject()
+            .toString();
         PhraseSuggestionBuilder filteredQuerySuggest = suggest.collateQuery(filterString);
         filteredQuerySuggest.collateParams(Collections.singletonMap("field", "title"));
         searchSuggest = searchSuggest("united states house of representatives elections in washington 2006", "title", filteredQuerySuggest);
@@ -1325,9 +1343,13 @@ public void testPhraseSuggesterCollate() throws InterruptedException, ExecutionE
         NumShards numShards = getNumShards("test");
 
         // collate suggest with bad query
-        String incorrectFilterString = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("test").field("title", "{{suggestion}}").endObject().endObject()
-        );
+        String incorrectFilterString = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("test")
+            .field("title", "{{suggestion}}")
+            .endObject()
+            .endObject()
+            .toString();
         PhraseSuggestionBuilder incorrectFilteredSuggest = suggest.collateQuery(incorrectFilterString);
         Map<String, SuggestionBuilder<?>> namedSuggestion = new HashMap<>();
         namedSuggestion.put("my_title_suggestion", incorrectFilteredSuggest);
@@ -1339,9 +1361,13 @@ public void testPhraseSuggesterCollate() throws InterruptedException, ExecutionE
         }
 
         // suggest with collation
-        String filterStringAsFilter = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("match_phrase").field("title", "{{suggestion}}").endObject().endObject()
-        );
+        String filterStringAsFilter = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("match_phrase")
+            .field("title", "{{suggestion}}")
+            .endObject()
+            .endObject()
+            .toString();
 
         PhraseSuggestionBuilder filteredFilterSuggest = suggest.collateQuery(filterStringAsFilter);
         searchSuggest = searchSuggest(
@@ -1352,9 +1378,13 @@ public void testPhraseSuggesterCollate() throws InterruptedException, ExecutionE
         assertSuggestionSize(searchSuggest, 0, 2, "title");
 
         // collate suggest with bad query
-        String filterStr = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("pprefix").field("title", "{{suggestion}}").endObject().endObject()
-        );
+        String filterStr = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("pprefix")
+            .field("title", "{{suggestion}}")
+            .endObject()
+            .endObject()
+            .toString();
 
         suggest.collateQuery(filterStr);
         try {
@@ -1365,14 +1395,13 @@ public void testPhraseSuggesterCollate() throws InterruptedException, ExecutionE
         }
 
         // collate script failure due to no additional params
-        String collateWithParams = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("{{query_type}}")
-                .field("{{query_field}}", "{{suggestion}}")
-                .endObject()
-                .endObject()
-        );
+        String collateWithParams = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("{{query_type}}")
+            .field("{{query_field}}", "{{suggestion}}")
+            .endObject()
+            .endObject()
+            .toString();
 
         try {
             searchSuggest("united states house of representatives elections in washington 2006", numShards.numPrimaries, namedSuggestion);
diff --git a/server/src/internalClusterTest/java/org/opensearch/similarity/SimilarityIT.java b/server/src/internalClusterTest/java/org/opensearch/similarity/SimilarityIT.java
index 929aac388b678..8c9bff9833462 100644
--- a/server/src/internalClusterTest/java/org/opensearch/similarity/SimilarityIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/similarity/SimilarityIT.java
@@ -32,17 +32,41 @@
 
 package org.opensearch.similarity;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
 
-public class SimilarityIT extends OpenSearchIntegTestCase {
+public class SimilarityIT extends ParameterizedOpenSearchIntegTestCase {
+    public SimilarityIT(Settings settings) {
+        super(settings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     public void testCustomBM25Similarity() throws Exception {
         try {
             client().admin().indices().prepareDelete("test").execute().actionGet();
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/AbortedRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/AbortedRestoreIT.java
index 6a8e45920e806..318c7d82380ca 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/AbortedRestoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/AbortedRestoreIT.java
@@ -32,17 +32,16 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.opensearch.action.admin.indices.recovery.RecoveryResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPoolStats;
-
 import org.hamcrest.Matcher;
 
 import java.util.List;
@@ -59,7 +58,7 @@
 public class AbortedRestoreIT extends AbstractSnapshotIntegTestCase {
 
     public void testAbortedRestoreAlsoAbortFileRestores() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
 
         final String indexName = "test-abort-restore";
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/BlobStoreIncrementalityIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/BlobStoreIncrementalityIT.java
index 5a3d2c6c4bafd..9a40ea2c95b28 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/BlobStoreIncrementalityIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/BlobStoreIncrementalityIT.java
@@ -59,7 +59,7 @@
 public class BlobStoreIncrementalityIT extends AbstractSnapshotIntegTestCase {
 
     public void testIncrementalBehaviorOnPrimaryFailover() throws InterruptedException, ExecutionException, IOException {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String primaryNode = internalCluster().startDataOnlyNode();
         final String indexName = "test-index";
         createIndex(
@@ -148,7 +148,7 @@ public void testIncrementalBehaviorOnPrimaryFailover() throws InterruptedExcepti
     }
 
     public void testForceMergeCausesFullSnapshot() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().ensureAtLeastNumDataNodes(2);
         final String indexName = "test-index";
         createIndex(indexName, Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).build());
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/CloneSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/CloneSnapshotIT.java
index 137be2187fe57..00e2d9bd92158 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/CloneSnapshotIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/CloneSnapshotIT.java
@@ -31,40 +31,42 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.action.ActionFuture;
+import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotIndexStatus;
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotStatus;
+import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.SnapshotsInProgress;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshots;
+import org.opensearch.index.snapshots.blobstore.IndexShardSnapshot;
+import org.opensearch.index.snapshots.blobstore.SnapshotFiles;
+import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.RepositoryData;
+import org.opensearch.repositories.RepositoryShardId;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.snapshots.mockstore.MockRepository;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
 
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
-
-import org.opensearch.action.ActionRunnable;
-import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
-import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshots;
-import org.opensearch.index.snapshots.blobstore.SnapshotFiles;
-import org.opensearch.repositories.IndexId;
-import org.opensearch.repositories.RepositoryShardId;
-import org.opensearch.repositories.blobstore.BlobStoreRepository;
-
-import java.nio.file.Path;
-
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 
@@ -72,7 +74,7 @@
 public class CloneSnapshotIT extends AbstractSnapshotIntegTestCase {
 
     public void testShardClone() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         final Path repoPath = randomRepoPath();
@@ -91,7 +93,7 @@ public void testShardClone() throws Exception {
         final String sourceSnapshot = "source-snapshot";
         final SnapshotInfo sourceSnapshotInfo = createFullSnapshot(repoName, sourceSnapshot);
 
-        final BlobStoreRepository repository = (BlobStoreRepository) internalCluster().getCurrentMasterNodeInstance(
+        final BlobStoreRepository repository = (BlobStoreRepository) internalCluster().getCurrentClusterManagerNodeInstance(
             RepositoriesService.class
         ).repository(repoName);
         final RepositoryData repositoryData = getRepositoryData(repoName);
@@ -143,7 +145,7 @@ public void testShardClone() throws Exception {
     }
 
     public void testCloneSnapshotIndex() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         createRepository(repoName, "fs");
@@ -171,8 +173,157 @@ public void testCloneSnapshotIndex() throws Exception {
         assertEquals(status1.getStats().getTotalSize(), status2.getStats().getTotalSize());
     }
 
+    public void testCloneShallowSnapshotIndex() throws Exception {
+        disableRepoConsistencyCheck("This test uses remote store repository");
+        final String remoteStoreRepoName = "remote-store-repo-name";
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "fs", snapshotRepoPath);
+
+        final String shallowSnapshotRepoName = "shallow-snapshot-repo-name";
+        final Path shallowSnapshotRepoPath = randomRepoPath();
+        createRepository(shallowSnapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy(shallowSnapshotRepoPath));
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 0);
+
+        indexRandomDocs(indexName, randomIntBetween(20, 100));
+
+        final String shallowSnapshot = "shallow-snapshot";
+        createFullSnapshot(shallowSnapshotRepoName, shallowSnapshot);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 1);
+
+        if (randomBoolean()) {
+            assertAcked(admin().indices().prepareDelete(indexName));
+        }
+
+        final String sourceSnapshot = shallowSnapshot;
+        final String targetSnapshot = "target-snapshot";
+        assertAcked(startClone(shallowSnapshotRepoName, sourceSnapshot, targetSnapshot, indexName, remoteStoreEnabledIndexName).get());
+        logger.info("Lock files count: {}", getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 2);
+    }
+
+    public void testShallowCloneNameAvailability() throws Exception {
+        disableRepoConsistencyCheck("This test uses remote store repository");
+        final String remoteStoreRepoName = "remote-store-repo-name";
+        final Path remoteStorePath = randomRepoPath().toAbsolutePath();
+        internalCluster().startClusterManagerOnlyNode(
+            Settings.builder()
+                .put(LARGE_SNAPSHOT_POOL_SETTINGS)
+                .put(remoteStoreClusterSettings(remoteStoreRepoName, remoteStorePath))
+                .build()
+        );
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStorePath));
+
+        final String shallowSnapshotRepoName = "shallow-snapshot-repo-name";
+        final Path shallowSnapshotRepoPath = randomRepoPath();
+        createRepository(shallowSnapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy(shallowSnapshotRepoPath));
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String shallowSnapshot1 = "snapshot1";
+        createFullSnapshot(shallowSnapshotRepoName, shallowSnapshot1);
+
+        final String shallowSnapshot2 = "snapshot2";
+        createFullSnapshot(shallowSnapshotRepoName, shallowSnapshot2);
+
+        ExecutionException ex = expectThrows(
+            ExecutionException.class,
+            () -> startClone(shallowSnapshotRepoName, shallowSnapshot1, shallowSnapshot2, indexName, remoteStoreEnabledIndexName).get()
+        );
+        assertThat(ex.getMessage(), containsString("snapshot with the same name already exists"));
+    }
+
+    public void testCloneAfterRepoShallowSettingEnabled() throws Exception {
+        disableRepoConsistencyCheck("This test uses remote store repository");
+        final String remoteStoreRepoName = "remote-store-repo-name";
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "fs", snapshotRepoPath);
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+        assertEquals(getSnapshot(snapshotRepoName, snapshot).state(), SnapshotState.SUCCESS);
+
+        // Updating the snapshot repository flag to enable shallow snapshots
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+        RepositoryMetadata updatedRepositoryMetadata = clusterAdmin().prepareGetRepositories(snapshotRepoName).get().repositories().get(0);
+        assertTrue(updatedRepositoryMetadata.settings().getAsBoolean(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), false));
+
+        final String targetSnapshot = "target-snapshot";
+        assertAcked(startClone(snapshotRepoName, snapshot, targetSnapshot, indexName, remoteStoreEnabledIndexName).get());
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 0);
+        assertEquals(getSnapshot(snapshotRepoName, targetSnapshot).isRemoteStoreIndexShallowCopyEnabled(), false);
+    }
+
+    public void testCloneAfterRepoShallowSettingDisabled() throws Exception {
+        disableRepoConsistencyCheck("This test uses remote store repository");
+        final String remoteStoreRepoName = "remote-store-repo-name";
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(remoteStoreRepoName, remoteStoreRepoPath));
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+        assertEquals(getSnapshot(snapshotRepoName, snapshot).state(), SnapshotState.SUCCESS);
+
+        // Updating the snapshot repository flag to enable shallow snapshots
+        createRepository(snapshotRepoName, "fs", snapshotRepoPath);
+        RepositoryMetadata updatedRepositoryMetadata = clusterAdmin().prepareGetRepositories(snapshotRepoName).get().repositories().get(0);
+        assertFalse(updatedRepositoryMetadata.settings().getAsBoolean(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), false));
+
+        final String targetSnapshot = "target-snapshot";
+        assertAcked(startClone(snapshotRepoName, snapshot, targetSnapshot, indexName, remoteStoreEnabledIndexName).get());
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 2);
+        assertEquals(getSnapshot(snapshotRepoName, targetSnapshot).isRemoteStoreIndexShallowCopyEnabled(), true);
+    }
+
     public void testClonePreventsSnapshotDelete() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         createRepository(repoName, "mock");
@@ -185,9 +336,9 @@ public void testClonePreventsSnapshotDelete() throws Exception {
         indexRandomDocs(indexName, randomIntBetween(20, 100));
 
         final String targetSnapshot = "target-snapshot";
-        blockNodeOnAnyFiles(repoName, masterName);
+        blockNodeOnAnyFiles(repoName, clusterManagerName);
         final ActionFuture<AcknowledgedResponse> cloneFuture = startClone(repoName, sourceSnapshot, targetSnapshot, indexName);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         assertFalse(cloneFuture.isDone());
 
         ConcurrentSnapshotExecutionException ex = expectThrows(
@@ -196,7 +347,7 @@ public void testClonePreventsSnapshotDelete() throws Exception {
         );
         assertThat(ex.getMessage(), containsString("cannot delete snapshot while it is being cloned"));
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         assertAcked(cloneFuture.get());
         final List<SnapshotStatus> status = clusterAdmin().prepareSnapshotStatus(repoName)
             .setSnapshots(sourceSnapshot, targetSnapshot)
@@ -210,7 +361,7 @@ public void testClonePreventsSnapshotDelete() throws Exception {
     }
 
     public void testConcurrentCloneAndSnapshot() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         createRepository(repoName, "mock");
@@ -234,7 +385,7 @@ public void testConcurrentCloneAndSnapshot() throws Exception {
 
     public void testLongRunningCloneAllowsConcurrentSnapshot() throws Exception {
         // large snapshot pool so blocked snapshot threads from cloning don't prevent concurrent snapshot finalizations
-        final String masterNode = internalCluster().startMasterOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -245,9 +396,9 @@ public void testLongRunningCloneAllowsConcurrentSnapshot() throws Exception {
         createFullSnapshot(repoName, sourceSnapshot);
 
         final String targetSnapshot = "target-snapshot";
-        blockMasterOnShardClone(repoName);
+        blockClusterManagerOnShardClone(repoName);
         final ActionFuture<AcknowledgedResponse> cloneFuture = startClone(repoName, sourceSnapshot, targetSnapshot, indexSlow);
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
         final String indexFast = "index-fast";
         createIndexWithRandomDocs(indexFast, randomIntBetween(20, 100));
@@ -257,13 +408,13 @@ public void testLongRunningCloneAllowsConcurrentSnapshot() throws Exception {
         );
 
         assertThat(cloneFuture.isDone(), is(false));
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
 
         assertAcked(cloneFuture.get());
     }
 
     public void testLongRunningSnapshotAllowsConcurrentClone() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -293,7 +444,7 @@ public void testLongRunningSnapshotAllowsConcurrentClone() throws Exception {
     }
 
     public void testDeletePreventsClone() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         createRepository(repoName, "mock");
@@ -306,9 +457,9 @@ public void testDeletePreventsClone() throws Exception {
         indexRandomDocs(indexName, randomIntBetween(20, 100));
 
         final String targetSnapshot = "target-snapshot";
-        blockNodeOnAnyFiles(repoName, masterName);
+        blockNodeOnAnyFiles(repoName, clusterManagerName);
         final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteSnapshot(repoName, sourceSnapshot);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         assertFalse(deleteFuture.isDone());
 
         ConcurrentSnapshotExecutionException ex = expectThrows(
@@ -317,13 +468,13 @@ public void testDeletePreventsClone() throws Exception {
         );
         assertThat(ex.getMessage(), containsString("cannot clone from snapshot that is being deleted"));
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         assertAcked(deleteFuture.get());
     }
 
     public void testBackToBackClonesForIndexNotInCluster() throws Exception {
         // large snapshot pool so blocked snapshot threads from cloning don't prevent concurrent snapshot finalizations
-        final String masterNode = internalCluster().startMasterOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -336,9 +487,9 @@ public void testBackToBackClonesForIndexNotInCluster() throws Exception {
         assertAcked(admin().indices().prepareDelete(indexBlocked).get());
 
         final String targetSnapshot1 = "target-snapshot";
-        blockMasterOnShardClone(repoName);
+        blockClusterManagerOnShardClone(repoName);
         final ActionFuture<AcknowledgedResponse> cloneFuture1 = startClone(repoName, sourceSnapshot, targetSnapshot1, indexBlocked);
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
         assertThat(cloneFuture1.isDone(), is(false));
 
         final int extraClones = randomIntBetween(1, 5);
@@ -366,7 +517,7 @@ public void testBackToBackClonesForIndexNotInCluster() throws Exception {
             assertFalse(extraSnapshotFuture.isDone());
         }
 
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         assertAcked(cloneFuture1.get());
 
         for (ActionFuture<AcknowledgedResponse> extraCloneFuture : extraCloneFutures) {
@@ -377,8 +528,8 @@ public void testBackToBackClonesForIndexNotInCluster() throws Exception {
         }
     }
 
-    public void testMasterFailoverDuringCloneStep1() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testClusterManagerFailoverDuringCloneStep1() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -388,13 +539,13 @@ public void testMasterFailoverDuringCloneStep1() throws Exception {
         final String sourceSnapshot = "source-snapshot";
         createFullSnapshot(repoName, sourceSnapshot);
 
-        blockMasterOnReadIndexMeta(repoName);
+        blockClusterManagerOnReadIndexMeta(repoName);
         final String cloneName = "target-snapshot";
         final ActionFuture<AcknowledgedResponse> cloneFuture = startCloneFromDataNode(repoName, sourceSnapshot, cloneName, testIndex);
         awaitNumberOfSnapshotsInProgress(1);
-        final String masterNode = internalCluster().getMasterName();
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
-        internalCluster().restartNode(masterNode);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
+        internalCluster().restartNode(clusterManagerNode);
         boolean cloneSucceeded = false;
         try {
             cloneFuture.actionGet(TimeValue.timeValueSeconds(30L));
@@ -404,16 +555,17 @@ public void testMasterFailoverDuringCloneStep1() throws Exception {
             // snapshot on disconnect slowly enough for it to work out
         }
 
-        awaitNoMoreRunningOperations(internalCluster().getMasterName());
+        awaitNoMoreRunningOperations(internalCluster().getClusterManagerName());
 
-        // Check if the clone operation worked out by chance as a result of the clone request being retried because of the master failover
+        // Check if the clone operation worked out by chance as a result of the clone request being retried
+        // because of the cluster-manager failover
         cloneSucceeded = cloneSucceeded
             || getRepositoryData(repoName).getSnapshotIds().stream().anyMatch(snapshotId -> snapshotId.getName().equals(cloneName));
         assertAllSnapshotsSuccessful(getRepositoryData(repoName), cloneSucceeded ? 2 : 1);
     }
 
     public void testFailsOnCloneMissingIndices() {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "repo-name";
         final Path repoPath = randomRepoPath();
@@ -430,9 +582,9 @@ public void testFailsOnCloneMissingIndices() {
         );
     }
 
-    public void testMasterFailoverDuringCloneStep2() throws Exception {
+    public void testClusterManagerFailoverDuringCloneStep2() throws Exception {
         // large snapshot pool so blocked snapshot threads from cloning don't prevent concurrent snapshot finalizations
-        internalCluster().startMasterOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
+        internalCluster().startClusterManagerOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -443,21 +595,21 @@ public void testMasterFailoverDuringCloneStep2() throws Exception {
         createFullSnapshot(repoName, sourceSnapshot);
 
         final String targetSnapshot = "target-snapshot";
-        blockMasterOnShardClone(repoName);
+        blockClusterManagerOnShardClone(repoName);
         final ActionFuture<AcknowledgedResponse> cloneFuture = startCloneFromDataNode(repoName, sourceSnapshot, targetSnapshot, testIndex);
         awaitNumberOfSnapshotsInProgress(1);
-        final String masterNode = internalCluster().getMasterName();
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
-        internalCluster().restartNode(masterNode);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
+        internalCluster().restartNode(clusterManagerNode);
         expectThrows(SnapshotException.class, cloneFuture::actionGet);
-        awaitNoMoreRunningOperations(internalCluster().getMasterName());
+        awaitNoMoreRunningOperations(internalCluster().getClusterManagerName());
 
         assertAllSnapshotsSuccessful(getRepositoryData(repoName), 2);
     }
 
     public void testExceptionDuringShardClone() throws Exception {
         // large snapshot pool so blocked snapshot threads from cloning don't prevent concurrent snapshot finalizations
-        internalCluster().startMasterOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
+        internalCluster().startClusterManagerOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -468,20 +620,20 @@ public void testExceptionDuringShardClone() throws Exception {
         createFullSnapshot(repoName, sourceSnapshot);
 
         final String targetSnapshot = "target-snapshot";
-        blockMasterFromFinalizingSnapshotOnSnapFile(repoName);
+        blockClusterManagerFromFinalizingSnapshotOnSnapFile(repoName);
         final ActionFuture<AcknowledgedResponse> cloneFuture = startCloneFromDataNode(repoName, sourceSnapshot, targetSnapshot, testIndex);
         awaitNumberOfSnapshotsInProgress(1);
-        final String masterNode = internalCluster().getMasterName();
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
-        unblockNode(repoName, masterNode);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
+        unblockNode(repoName, clusterManagerNode);
         expectThrows(SnapshotException.class, cloneFuture::actionGet);
-        awaitNoMoreRunningOperations(internalCluster().getMasterName());
+        awaitNoMoreRunningOperations(internalCluster().getClusterManagerName());
         assertAllSnapshotsSuccessful(getRepositoryData(repoName), 1);
         assertAcked(startDeleteSnapshot(repoName, sourceSnapshot).get());
     }
 
     public void testDoesNotStartOnBrokenSourceSnapshot() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -490,8 +642,8 @@ public void testDoesNotStartOnBrokenSourceSnapshot() throws Exception {
 
         final String sourceSnapshot = "source-snapshot";
         blockDataNode(repoName, dataNode);
-        final Client masterClient = internalCluster().masterClient();
-        final ActionFuture<CreateSnapshotResponse> sourceSnapshotFuture = masterClient.admin()
+        final Client clusterManagerClient = internalCluster().clusterManagerClient();
+        final ActionFuture<CreateSnapshotResponse> sourceSnapshotFuture = clusterManagerClient.admin()
             .cluster()
             .prepareCreateSnapshot(repoName, sourceSnapshot)
             .setWaitForCompletion(true)
@@ -503,7 +655,7 @@ public void testDoesNotStartOnBrokenSourceSnapshot() throws Exception {
 
         final SnapshotException sne = expectThrows(
             SnapshotException.class,
-            () -> startClone(masterClient, repoName, sourceSnapshot, "target-snapshot", testIndex).actionGet(
+            () -> startClone(clusterManagerClient, repoName, sourceSnapshot, "target-snapshot", testIndex).actionGet(
                 TimeValue.timeValueSeconds(30L)
             )
         );
@@ -516,7 +668,7 @@ public void testDoesNotStartOnBrokenSourceSnapshot() throws Exception {
     }
 
     public void testStartSnapshotWithSuccessfulShardClonePendingFinalization() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -527,18 +679,18 @@ public void testStartSnapshotWithSuccessfulShardClonePendingFinalization() throw
         final String sourceSnapshot = "source-snapshot";
         createFullSnapshot(repoName, sourceSnapshot);
 
-        blockMasterOnWriteIndexFile(repoName);
+        blockClusterManagerOnWriteIndexFile(repoName);
         final String cloneName = "clone-blocked";
         final ActionFuture<AcknowledgedResponse> blockedClone = startClone(repoName, sourceSnapshot, cloneName, indexName);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         awaitNumberOfSnapshotsInProgress(1);
         blockNodeOnAnyFiles(repoName, dataNode);
         final ActionFuture<CreateSnapshotResponse> otherSnapshot = startFullSnapshot(repoName, "other-snapshot");
         awaitNumberOfSnapshotsInProgress(2);
         assertFalse(blockedClone.isDone());
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         awaitNumberOfSnapshotsInProgress(1);
-        awaitMasterFinishRepoOperations();
+        awaitClusterManagerFinishRepoOperations();
         unblockNode(repoName, dataNode);
         assertAcked(blockedClone.get());
         assertEquals(getSnapshot(repoName, cloneName).state(), SnapshotState.SUCCESS);
@@ -546,7 +698,7 @@ public void testStartSnapshotWithSuccessfulShardClonePendingFinalization() throw
     }
 
     public void testStartCloneWithSuccessfulShardClonePendingFinalization() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -557,18 +709,18 @@ public void testStartCloneWithSuccessfulShardClonePendingFinalization() throws E
         final String sourceSnapshot = "source-snapshot";
         createFullSnapshot(repoName, sourceSnapshot);
 
-        blockMasterOnWriteIndexFile(repoName);
+        blockClusterManagerOnWriteIndexFile(repoName);
         final String cloneName = "clone-blocked";
         final ActionFuture<AcknowledgedResponse> blockedClone = startClone(repoName, sourceSnapshot, cloneName, indexName);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         awaitNumberOfSnapshotsInProgress(1);
         final String otherCloneName = "other-clone";
         final ActionFuture<AcknowledgedResponse> otherClone = startClone(repoName, sourceSnapshot, otherCloneName, indexName);
         awaitNumberOfSnapshotsInProgress(2);
         assertFalse(blockedClone.isDone());
-        unblockNode(repoName, masterName);
-        awaitNoMoreRunningOperations(masterName);
-        awaitMasterFinishRepoOperations();
+        unblockNode(repoName, clusterManagerName);
+        awaitNoMoreRunningOperations(clusterManagerName);
+        awaitClusterManagerFinishRepoOperations();
         assertAcked(blockedClone.get());
         assertAcked(otherClone.get());
         assertEquals(getSnapshot(repoName, cloneName).state(), SnapshotState.SUCCESS);
@@ -576,7 +728,7 @@ public void testStartCloneWithSuccessfulShardClonePendingFinalization() throws E
     }
 
     public void testStartCloneWithSuccessfulShardSnapshotPendingFinalization() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -587,9 +739,9 @@ public void testStartCloneWithSuccessfulShardSnapshotPendingFinalization() throw
         final String sourceSnapshot = "source-snapshot";
         createFullSnapshot(repoName, sourceSnapshot);
 
-        blockMasterOnWriteIndexFile(repoName);
+        blockClusterManagerOnWriteIndexFile(repoName);
         final ActionFuture<CreateSnapshotResponse> blockedSnapshot = startFullSnapshot(repoName, "snap-blocked");
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         awaitNumberOfSnapshotsInProgress(1);
         final String cloneName = "clone";
         final ActionFuture<AcknowledgedResponse> clone = startClone(repoName, sourceSnapshot, cloneName, indexName);
@@ -602,11 +754,11 @@ public void testStartCloneWithSuccessfulShardSnapshotPendingFinalization() throw
             });
             assertFalse(blockedSnapshot.isDone());
         } finally {
-            unblockNode(repoName, masterName);
+            unblockNode(repoName, clusterManagerName);
         }
         awaitNoMoreRunningOperations();
 
-        awaitMasterFinishRepoOperations();
+        awaitClusterManagerFinishRepoOperations();
 
         assertSuccessful(blockedSnapshot);
         assertAcked(clone.get());
@@ -641,13 +793,13 @@ private static ActionFuture<AcknowledgedResponse> startClone(
         return client.admin().cluster().prepareCloneSnapshot(repoName, sourceSnapshot, targetSnapshot).setIndices(indices).execute();
     }
 
-    private void blockMasterOnReadIndexMeta(String repoName) {
-        ((MockRepository) internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repoName))
+    private void blockClusterManagerOnReadIndexMeta(String repoName) {
+        ((MockRepository) internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class).repository(repoName))
             .setBlockOnReadIndexMeta();
     }
 
-    private void blockMasterOnShardClone(String repoName) {
-        ((MockRepository) internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repoName))
+    private void blockClusterManagerOnShardClone(String repoName) {
+        ((MockRepository) internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class).repository(repoName))
             .setBlockOnWriteShardLevelMeta();
     }
 
@@ -688,18 +840,14 @@ private static BlobStoreIndexShardSnapshot readShardSnapshot(
         RepositoryShardId repositoryShardId,
         SnapshotId snapshotId
     ) {
-        return PlainActionFuture.get(
-            f -> repository.threadPool()
-                .generic()
-                .execute(
-                    ActionRunnable.supply(
-                        f,
-                        () -> repository.loadShardSnapshot(
-                            repository.shardContainer(repositoryShardId.index(), repositoryShardId.shardId()),
-                            snapshotId
-                        )
-                    )
-                )
-        );
+        return PlainActionFuture.get(f -> repository.threadPool().generic().execute(ActionRunnable.supply(f, () -> {
+            IndexShardSnapshot indexShardSnapshot = repository.loadShardSnapshot(
+                repository.shardContainer(repositoryShardId.index(), repositoryShardId.shardId()),
+                snapshotId
+            );
+            assert indexShardSnapshot instanceof BlobStoreIndexShardSnapshot
+                : "indexShardSnapshot should be an instance of BlobStoreIndexShardSnapshot";
+            return (BlobStoreIndexShardSnapshot) indexShardSnapshot;
+        })));
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/ConcurrentSnapshotsIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/ConcurrentSnapshotsIT.java
index 9adb0ff6260e8..4e90a6cd007b2 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/ConcurrentSnapshotsIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/ConcurrentSnapshotsIT.java
@@ -31,11 +31,7 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
@@ -47,11 +43,13 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.SnapshotDeletionsInProgress;
 import org.opensearch.cluster.SnapshotsInProgress;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.UncategorizedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 import org.opensearch.discovery.AbstractDisruptionTestCase;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoryData;
@@ -59,8 +57,8 @@
 import org.opensearch.repositories.ShardGenerations;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.snapshots.mockstore.MockRepository;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.disruption.NetworkDisruption;
 import org.opensearch.test.transport.MockTransportService;
 
@@ -106,7 +104,7 @@ protected Settings nodeSettings(int nodeOrdinal) {
     }
 
     public void testLongRunningSnapshotAllowsConcurrentSnapshot() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -139,7 +137,7 @@ public void testLongRunningSnapshotAllowsConcurrentSnapshot() throws Exception {
     }
 
     public void testDeletesAreBatched() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -205,7 +203,7 @@ public void testDeletesAreBatched() throws Exception {
     }
 
     public void testBlockedRepoDoesNotBlockOtherRepos() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String blockedRepoName = "test-repo-blocked";
         final String otherRepoName = "test-repo";
@@ -224,14 +222,14 @@ public void testBlockedRepoDoesNotBlockOtherRepos() throws Exception {
             .setWaitForCompletion(false)
             .get();
 
-        unblockNode(blockedRepoName, internalCluster().getMasterName());
+        unblockNode(blockedRepoName, internalCluster().getClusterManagerName());
         expectThrows(SnapshotException.class, createSlowFuture::actionGet);
 
         assertBusy(() -> assertThat(currentSnapshots(otherRepoName), empty()), 30L, TimeUnit.SECONDS);
     }
 
     public void testMultipleReposAreIndependent() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         // We're blocking a some of the snapshot threads when we block the first repo below so we have to make sure we have enough threads
         // left for the second concurrent snapshot.
         final String dataNode = startDataNodeWithLargeSnapshotPool();
@@ -255,7 +253,7 @@ public void testMultipleReposAreIndependent() throws Exception {
     }
 
     public void testMultipleReposAreIndependent2() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         // We're blocking a some of the snapshot threads when we block the first repo below so we have to make sure we have enough threads
         // left for the second repository's concurrent operations.
         final String dataNode = startDataNodeWithLargeSnapshotPool();
@@ -280,7 +278,7 @@ public void testMultipleReposAreIndependent2() throws Exception {
     }
 
     public void testMultipleReposAreIndependent3() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String blockedRepoName = "test-repo-blocked";
         final String otherRepoName = "test-repo";
@@ -289,19 +287,19 @@ public void testMultipleReposAreIndependent3() throws Exception {
         createIndexWithContent("test-index");
 
         createFullSnapshot(blockedRepoName, "blocked-snapshot");
-        blockNodeOnAnyFiles(blockedRepoName, masterNode);
+        blockNodeOnAnyFiles(blockedRepoName, clusterManagerNode);
         final ActionFuture<AcknowledgedResponse> slowDeleteFuture = startDeleteSnapshot(blockedRepoName, "*");
 
         logger.info("--> waiting for concurrent snapshot(s) to finish");
         createNSnapshots(otherRepoName, randomIntBetween(1, 5));
         assertAcked(startDeleteSnapshot(otherRepoName, "*").get());
 
-        unblockNode(blockedRepoName, masterNode);
+        unblockNode(blockedRepoName, clusterManagerNode);
         assertAcked(slowDeleteFuture.actionGet());
     }
 
     public void testSnapshotRunsAfterInProgressDelete() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -312,13 +310,13 @@ public void testSnapshotRunsAfterInProgressDelete() throws Exception {
         final String firstSnapshot = "first-snapshot";
         createFullSnapshot(repoName, firstSnapshot);
 
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
         final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteSnapshot(repoName, firstSnapshot);
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
         final ActionFuture<CreateSnapshotResponse> snapshotFuture = startFullSnapshot(repoName, "second-snapshot");
 
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         final UncategorizedExecutionException ex = expectThrows(UncategorizedExecutionException.class, deleteFuture::actionGet);
         assertThat(ex.getRootCause(), instanceOf(IOException.class));
 
@@ -326,7 +324,7 @@ public void testSnapshotRunsAfterInProgressDelete() throws Exception {
     }
 
     public void testAbortOneOfMultipleSnapshots() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -386,7 +384,7 @@ public void testAbortOneOfMultipleSnapshots() throws Exception {
     }
 
     public void testCascadedAborts() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -447,8 +445,8 @@ public void testCascadedAborts() throws Exception {
         assertThat(client().admin().cluster().prepareGetSnapshots(repoName).get().getSnapshots(), empty());
     }
 
-    public void testMasterFailOverWithQueuedDeletes() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testClusterManagerFailOverWithQueuedDeletes() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -458,7 +456,10 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
 
         final String firstSnapshot = "snapshot-one";
         blockDataNode(repoName, dataNode);
-        final ActionFuture<CreateSnapshotResponse> firstSnapshotResponse = startFullSnapshotFromNonMasterClient(repoName, firstSnapshot);
+        final ActionFuture<CreateSnapshotResponse> firstSnapshotResponse = startFullSnapshotFromNonClusterManagerClient(
+            repoName,
+            firstSnapshot
+        );
         waitForBlock(dataNode, repoName, TimeValue.timeValueSeconds(30L));
 
         final String dataNode2 = internalCluster().startDataOnlyNode();
@@ -475,11 +476,14 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
             return snapshotsInProgress.entries().size() == 2 && snapshotHasCompletedShard(secondSnapshot, snapshotsInProgress);
         });
 
-        final ActionFuture<AcknowledgedResponse> firstDeleteFuture = startDeleteFromNonMasterClient(repoName, firstSnapshot);
+        final ActionFuture<AcknowledgedResponse> firstDeleteFuture = startDeleteFromNonClusterManagerClient(repoName, firstSnapshot);
         awaitNDeletionsInProgress(1);
 
         blockNodeOnAnyFiles(repoName, dataNode2);
-        final ActionFuture<CreateSnapshotResponse> snapshotThreeFuture = startFullSnapshotFromNonMasterClient(repoName, "snapshot-three");
+        final ActionFuture<CreateSnapshotResponse> snapshotThreeFuture = startFullSnapshotFromNonClusterManagerClient(
+            repoName,
+            "snapshot-three"
+        );
         waitForBlock(dataNode2, repoName, TimeValue.timeValueSeconds(30L));
 
         assertThat(firstSnapshotResponse.isDone(), is(false));
@@ -488,7 +492,7 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
         logger.info("--> waiting for all three snapshots to show up as in-progress");
         assertBusy(() -> assertThat(currentSnapshots(repoName), hasSize(3)), 30L, TimeUnit.SECONDS);
 
-        final ActionFuture<AcknowledgedResponse> deleteAllSnapshots = startDeleteFromNonMasterClient(repoName, "*");
+        final ActionFuture<AcknowledgedResponse> deleteAllSnapshots = startDeleteFromNonClusterManagerClient(repoName, "*");
         logger.info("--> wait for delete to be enqueued in cluster state");
         awaitClusterState(state -> {
             final SnapshotDeletionsInProgress deletionsInProgress = state.custom(SnapshotDeletionsInProgress.TYPE);
@@ -506,8 +510,8 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
             }
         }, 30L, TimeUnit.SECONDS);
 
-        logger.info("--> stopping current master node");
-        internalCluster().stopCurrentMasterNode();
+        logger.info("--> stopping current cluster-manager node");
+        internalCluster().stopCurrentClusterManagerNode();
 
         unblockNode(repoName, dataNode);
         unblockNode(repoName, dataNode2);
@@ -516,13 +520,14 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
             try {
                 assertAcked(deleteFuture.actionGet());
             } catch (RepositoryException rex) {
-                // rarely the master node fails over twice when shutting down the initial master and fails the transport listener
+                // rarely the cluster-manager node fails over twice
+                // when shutting down the initial cluster-manager and fails the transport listener
                 assertThat(rex.repository(), is("_all"));
                 assertThat(rex.getMessage(), endsWith("Failed to update cluster state during repository operation"));
             } catch (SnapshotMissingException sme) {
-                // very rarely a master node fail-over happens at such a time that the client on the data-node sees a disconnect exception
-                // after the master has already started the delete, leading to the delete retry to run into a situation where the
-                // snapshot has already been deleted potentially
+                // very rarely a cluster-manager node fail-over happens at such a time
+                // that the client on the data-node sees a disconnect exception after the cluster-manager has already started the delete,
+                // leading to the delete retry to run into a situation where the snapshot has already been deleted potentially
                 assertThat(sme.getSnapshotName(), is(firstSnapshot));
             }
         }
@@ -540,7 +545,7 @@ public void testMasterFailOverWithQueuedDeletes() throws Exception {
     }
 
     public void testAssertMultipleSnapshotsAndPrimaryFailOver() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -551,7 +556,10 @@ public void testAssertMultipleSnapshotsAndPrimaryFailOver() throws Exception {
         index(testIndex, "_doc", "some_id", "foo", "bar");
 
         blockDataNode(repoName, dataNode);
-        final ActionFuture<CreateSnapshotResponse> firstSnapshotResponse = startFullSnapshotFromMasterClient(repoName, "snapshot-one");
+        final ActionFuture<CreateSnapshotResponse> firstSnapshotResponse = startFullSnapshotFromClusterManagerClient(
+            repoName,
+            "snapshot-one"
+        );
         waitForBlock(dataNode, repoName, TimeValue.timeValueSeconds(30L));
 
         internalCluster().startDataOnlyNode();
@@ -559,7 +567,10 @@ public void testAssertMultipleSnapshotsAndPrimaryFailOver() throws Exception {
         ensureGreen(testIndex);
 
         final String secondSnapshot = "snapshot-two";
-        final ActionFuture<CreateSnapshotResponse> secondSnapshotResponse = startFullSnapshotFromMasterClient(repoName, secondSnapshot);
+        final ActionFuture<CreateSnapshotResponse> secondSnapshotResponse = startFullSnapshotFromClusterManagerClient(
+            repoName,
+            secondSnapshot
+        );
 
         // make sure second snapshot is in progress before restarting data node
         waitUntilInprogress(repoName, secondSnapshot, TimeValue.timeValueSeconds(5L));
@@ -571,16 +582,16 @@ public void testAssertMultipleSnapshotsAndPrimaryFailOver() throws Exception {
     }
 
     public void testQueuedDeletesWithFailures() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-one");
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
         final ActionFuture<AcknowledgedResponse> firstDeleteFuture = startDeleteSnapshot(repoName, "*");
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
         final ActionFuture<CreateSnapshotResponse> snapshotFuture = startFullSnapshot(repoName, "snapshot-queued");
         awaitNumberOfSnapshotsInProgress(1);
@@ -588,7 +599,7 @@ public void testQueuedDeletesWithFailures() throws Exception {
         final ActionFuture<AcknowledgedResponse> secondDeleteFuture = startDeleteSnapshot(repoName, "*");
         awaitNDeletionsInProgress(2);
 
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         expectThrows(UncategorizedExecutionException.class, firstDeleteFuture::actionGet);
 
         // Second delete works out cleanly since the repo is unblocked now
@@ -601,7 +612,7 @@ public void testQueuedDeletesWithFailures() throws Exception {
     }
 
     public void testQueuedDeletesWithOverlap() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -615,7 +626,7 @@ public void testQueuedDeletesWithOverlap() throws Exception {
         final ActionFuture<AcknowledgedResponse> secondDeleteFuture = startDeleteSnapshot(repoName, "*");
         awaitNDeletionsInProgress(2);
 
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         assertThat(firstDeleteFuture.get().isAcknowledged(), is(true));
 
         // Second delete works out cleanly since the repo is unblocked now
@@ -627,8 +638,8 @@ public void testQueuedDeletesWithOverlap() throws Exception {
         assertThat(client().admin().cluster().prepareGetSnapshots(repoName).get().getSnapshots(), empty());
     }
 
-    public void testQueuedOperationsOnMasterRestart() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testQueuedOperationsOnClusterManagerRestart() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -642,39 +653,39 @@ public void testQueuedOperationsOnMasterRestart() throws Exception {
         startDeleteSnapshot(repoName, "*");
         awaitNDeletionsInProgress(2);
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
         ensureStableCluster(3);
 
         awaitNoMoreRunningOperations();
     }
 
-    public void testQueuedOperationsOnMasterDisconnect() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testQueuedOperationsOnClusterManagerDisconnect() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-one");
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
-        final String masterNode = internalCluster().getMasterName();
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
 
-        blockNodeOnAnyFiles(repoName, masterNode);
-        ActionFuture<AcknowledgedResponse> firstDeleteFuture = client(masterNode).admin()
+        blockNodeOnAnyFiles(repoName, clusterManagerNode);
+        ActionFuture<AcknowledgedResponse> firstDeleteFuture = client(clusterManagerNode).admin()
             .cluster()
             .prepareDeleteSnapshot(repoName, "*")
             .execute();
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
-        final ActionFuture<CreateSnapshotResponse> createThirdSnapshot = client(masterNode).admin()
+        final ActionFuture<CreateSnapshotResponse> createThirdSnapshot = client(clusterManagerNode).admin()
             .cluster()
             .prepareCreateSnapshot(repoName, "snapshot-three")
             .setWaitForCompletion(true)
             .execute();
         awaitNumberOfSnapshotsInProgress(1);
 
-        final ActionFuture<AcknowledgedResponse> secondDeleteFuture = client(masterNode).admin()
+        final ActionFuture<AcknowledgedResponse> secondDeleteFuture = client(clusterManagerNode).admin()
             .cluster()
             .prepareDeleteSnapshot(repoName, "*")
             .execute();
@@ -682,7 +693,7 @@ public void testQueuedOperationsOnMasterDisconnect() throws Exception {
 
         networkDisruption.startDisrupting();
         ensureStableCluster(3, dataNode);
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         networkDisruption.stopDisrupting();
 
         logger.info("--> make sure all failing requests get a response");
@@ -693,31 +704,31 @@ public void testQueuedOperationsOnMasterDisconnect() throws Exception {
         awaitNoMoreRunningOperations();
     }
 
-    public void testQueuedOperationsOnMasterDisconnectAndRepoFailure() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testQueuedOperationsOnClusterManagerDisconnectAndRepoFailure() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-one");
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
-        final String masterNode = internalCluster().getMasterName();
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
 
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
-        final ActionFuture<CreateSnapshotResponse> firstFailedSnapshotFuture = startFullSnapshotFromMasterClient(
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
+        final ActionFuture<CreateSnapshotResponse> firstFailedSnapshotFuture = startFullSnapshotFromClusterManagerClient(
             repoName,
             "failing-snapshot-1"
         );
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
-        final ActionFuture<CreateSnapshotResponse> secondFailedSnapshotFuture = startFullSnapshotFromMasterClient(
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
+        final ActionFuture<CreateSnapshotResponse> secondFailedSnapshotFuture = startFullSnapshotFromClusterManagerClient(
             repoName,
             "failing-snapshot-2"
         );
         awaitNumberOfSnapshotsInProgress(2);
 
-        final ActionFuture<AcknowledgedResponse> failedDeleteFuture = client(masterNode).admin()
+        final ActionFuture<AcknowledgedResponse> failedDeleteFuture = client(clusterManagerNode).admin()
             .cluster()
             .prepareDeleteSnapshot(repoName, "*")
             .execute();
@@ -725,7 +736,7 @@ public void testQueuedOperationsOnMasterDisconnectAndRepoFailure() throws Except
 
         networkDisruption.startDisrupting();
         ensureStableCluster(3, dataNode);
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         networkDisruption.stopDisrupting();
 
         logger.info("--> make sure all failing requests get a response");
@@ -736,10 +747,10 @@ public void testQueuedOperationsOnMasterDisconnectAndRepoFailure() throws Except
         awaitNoMoreRunningOperations();
     }
 
-    public void testQueuedOperationsAndBrokenRepoOnMasterFailOver() throws Exception {
+    public void testQueuedOperationsAndBrokenRepoOnClusterManagerFailOver() throws Exception {
         disableRepoConsistencyCheck("This test corrupts the repository on purpose");
 
-        internalCluster().startMasterOnlyNodes(3);
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
@@ -755,20 +766,20 @@ public void testQueuedOperationsAndBrokenRepoOnMasterFailOver() throws Exception
 
         client().admin().cluster().prepareCreateSnapshot(repoName, "snapshot-three").setWaitForCompletion(false).get();
 
-        final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteFromNonMasterClient(repoName, "*");
+        final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteFromNonClusterManagerClient(repoName, "*");
         awaitNDeletionsInProgress(2);
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
         ensureStableCluster(3);
 
         awaitNoMoreRunningOperations();
         expectThrows(RepositoryException.class, deleteFuture::actionGet);
     }
 
-    public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOver() throws Exception {
+    public void testQueuedSnapshotOperationsAndBrokenRepoOnClusterManagerFailOver() throws Exception {
         disableRepoConsistencyCheck("This test corrupts the repository on purpose");
 
-        internalCluster().startMasterOnlyNodes(3);
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
@@ -777,15 +788,15 @@ public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOver() throws E
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
         final long generation = getRepositoryData(repoName).getGenId();
-        final String masterNode = internalCluster().getMasterName();
-        blockNodeOnAnyFiles(repoName, masterNode);
-        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonMasterClient(repoName, "snapshot-three");
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        blockNodeOnAnyFiles(repoName, clusterManagerNode);
+        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-three");
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
         corruptIndexN(repoPath, generation);
 
-        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonMasterClient(repoName, "snapshot-four");
-        internalCluster().stopCurrentMasterNode();
+        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-four");
+        internalCluster().stopCurrentClusterManagerNode();
         ensureStableCluster(3);
 
         awaitNoMoreRunningOperations();
@@ -793,10 +804,10 @@ public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOver() throws E
         expectThrows(OpenSearchException.class, snapshotFour::actionGet);
     }
 
-    public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOver2() throws Exception {
+    public void testQueuedSnapshotOperationsAndBrokenRepoOnClusterManagerFailOver2() throws Exception {
         disableRepoConsistencyCheck("This test corrupts the repository on purpose");
 
-        internalCluster().startMasterOnlyNodes(3);
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
@@ -805,31 +816,31 @@ public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOver2() throws
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
         final long generation = getRepositoryData(repoName).getGenId();
-        final String masterNode = internalCluster().getMasterName();
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
-        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonMasterClient(repoName, "snapshot-three");
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
+        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-three");
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
 
         corruptIndexN(repoPath, generation);
 
-        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonMasterClient(repoName, "snapshot-four");
+        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-four");
         awaitNumberOfSnapshotsInProgress(2);
 
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
         networkDisruption.startDisrupting();
         ensureStableCluster(3, dataNode);
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         networkDisruption.stopDisrupting();
         awaitNoMoreRunningOperations();
         expectThrows(OpenSearchException.class, snapshotThree::actionGet);
         expectThrows(OpenSearchException.class, snapshotFour::actionGet);
     }
 
-    public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOverMultipleRepos() throws Exception {
+    public void testQueuedSnapshotOperationsAndBrokenRepoOnClusterManagerFailOverMultipleRepos() throws Exception {
         disableRepoConsistencyCheck("This test corrupts the repository on purpose");
 
-        internalCluster().startMasterOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
+        internalCluster().startClusterManagerOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
@@ -837,32 +848,32 @@ public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOverMultipleRep
         createIndexWithContent("index-one");
         createNSnapshots(repoName, randomIntBetween(2, 5));
 
-        final String masterNode = internalCluster().getMasterName();
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
 
         final String blockedRepoName = "repo-blocked";
         createRepository(blockedRepoName, "mock");
         createNSnapshots(blockedRepoName, randomIntBetween(1, 5));
-        blockNodeOnAnyFiles(blockedRepoName, masterNode);
-        final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteFromNonMasterClient(blockedRepoName, "*");
-        waitForBlock(masterNode, blockedRepoName, TimeValue.timeValueSeconds(30L));
+        blockNodeOnAnyFiles(blockedRepoName, clusterManagerNode);
+        final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteFromNonClusterManagerClient(blockedRepoName, "*");
+        waitForBlock(clusterManagerNode, blockedRepoName, TimeValue.timeValueSeconds(30L));
         awaitNDeletionsInProgress(1);
-        final ActionFuture<CreateSnapshotResponse> createBlockedSnapshot = startFullSnapshotFromNonMasterClient(
+        final ActionFuture<CreateSnapshotResponse> createBlockedSnapshot = startFullSnapshotFromNonClusterManagerClient(
             blockedRepoName,
             "queued-snapshot"
         );
         awaitNumberOfSnapshotsInProgress(1);
 
         final long generation = getRepositoryData(repoName).getGenId();
-        blockNodeOnAnyFiles(repoName, masterNode);
-        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonMasterClient(repoName, "snapshot-three");
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        blockNodeOnAnyFiles(repoName, clusterManagerNode);
+        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-three");
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
         awaitNumberOfSnapshotsInProgress(2);
 
         corruptIndexN(repoPath, generation);
 
-        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonMasterClient(repoName, "snapshot-four");
+        final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshotFromNonClusterManagerClient(repoName, "snapshot-four");
         awaitNumberOfSnapshotsInProgress(3);
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
         ensureStableCluster(3);
 
         awaitNoMoreRunningOperations();
@@ -872,13 +883,13 @@ public void testQueuedSnapshotOperationsAndBrokenRepoOnMasterFailOverMultipleRep
         try {
             createBlockedSnapshot.actionGet();
         } catch (OpenSearchException ex) {
-            // Ignored, thrown most of the time but due to retries when shutting down the master could randomly pass when the request is
-            // retried and gets executed after the above delete
+            // Ignored, thrown most of the time but due to retries when shutting down the cluster-manager could randomly pass
+            // when the request is retried and gets executed after the above delete
         }
     }
 
     public void testMultipleSnapshotsQueuedAfterDelete() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -889,7 +900,7 @@ public void testMultipleSnapshotsQueuedAfterDelete() throws Exception {
         final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshot(repoName, "snapshot-three");
         final ActionFuture<CreateSnapshotResponse> snapshotFour = startFullSnapshot(repoName, "snapshot-four");
 
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
 
         assertSuccessful(snapshotThree);
         assertSuccessful(snapshotFour);
@@ -897,7 +908,7 @@ public void testMultipleSnapshotsQueuedAfterDelete() throws Exception {
     }
 
     public void testMultiplePartialSnapshotsQueuedAfterDelete() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -911,7 +922,7 @@ public void testMultiplePartialSnapshotsQueuedAfterDelete() throws Exception {
         awaitNumberOfSnapshotsInProgress(2);
 
         assertAcked(client().admin().indices().prepareDelete("index-two"));
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
 
         assertThat(snapshotThree.get().getSnapshotInfo().state(), is(SnapshotState.PARTIAL));
         assertThat(snapshotFour.get().getSnapshotInfo().state(), is(SnapshotState.PARTIAL));
@@ -919,7 +930,7 @@ public void testMultiplePartialSnapshotsQueuedAfterDelete() throws Exception {
     }
 
     public void testQueuedSnapshotsWaitingForShardReady() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNodes(2);
         final String repoName = "test-repo";
         createRepository(repoName, "fs");
@@ -977,7 +988,7 @@ public void testQueuedSnapshotsWaitingForShardReady() throws Exception {
     }
 
     public void testBackToBackQueuedDeletes() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -990,7 +1001,7 @@ public void testBackToBackQueuedDeletes() throws Exception {
         final ActionFuture<AcknowledgedResponse> deleteSnapshotTwo = startDeleteSnapshot(repoName, snapshotTwo);
         awaitNDeletionsInProgress(2);
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         assertAcked(deleteSnapshotOne.get());
         assertAcked(deleteSnapshotTwo.get());
 
@@ -1001,7 +1012,7 @@ public void testBackToBackQueuedDeletes() throws Exception {
     }
 
     public void testQueuedOperationsAfterFinalizationFailure() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -1011,76 +1022,76 @@ public void testQueuedOperationsAfterFinalizationFailure() throws Exception {
 
         final ActionFuture<CreateSnapshotResponse> snapshotThree = startAndBlockFailingFullSnapshot(repoName, "snap-other");
 
-        final String masterName = internalCluster().getMasterName();
+        final String clusterManagerName = internalCluster().getClusterManagerName();
 
         final String snapshotOne = snapshotNames.get(0);
         final ActionFuture<AcknowledgedResponse> deleteSnapshotOne = startDeleteSnapshot(repoName, snapshotOne);
         awaitNDeletionsInProgress(1);
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
 
         expectThrows(SnapshotException.class, snapshotThree::actionGet);
         assertAcked(deleteSnapshotOne.get());
     }
 
     public void testStartDeleteDuringFinalizationCleanup() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-test");
         createNSnapshots(repoName, randomIntBetween(1, 5));
         final String snapshotName = "snap-name";
-        blockMasterFromDeletingIndexNFile(repoName);
+        blockClusterManagerFromDeletingIndexNFile(repoName);
         final ActionFuture<CreateSnapshotResponse> snapshotFuture = startFullSnapshot(repoName, snapshotName);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteSnapshot(repoName, snapshotName);
         awaitNDeletionsInProgress(1);
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         assertSuccessful(snapshotFuture);
         assertAcked(deleteFuture.get(30L, TimeUnit.SECONDS));
     }
 
     public void testEquivalentDeletesAreDeduplicated() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-test");
         createNSnapshots(repoName, randomIntBetween(1, 5));
 
-        blockNodeOnAnyFiles(repoName, masterName);
+        blockNodeOnAnyFiles(repoName, clusterManagerName);
         final int deletes = randomIntBetween(2, 10);
         final List<ActionFuture<AcknowledgedResponse>> deleteResponses = new ArrayList<>(deletes);
         for (int i = 0; i < deletes; ++i) {
             deleteResponses.add(client().admin().cluster().prepareDeleteSnapshot(repoName, "*").execute());
         }
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         awaitNDeletionsInProgress(1);
         for (ActionFuture<AcknowledgedResponse> deleteResponse : deleteResponses) {
             assertFalse(deleteResponse.isDone());
         }
         awaitNDeletionsInProgress(1);
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         for (ActionFuture<AcknowledgedResponse> deleteResponse : deleteResponses) {
             assertAcked(deleteResponse.get());
         }
     }
 
-    public void testMasterFailoverOnFinalizationLoop() throws Exception {
-        internalCluster().startMasterOnlyNodes(3);
+    public void testClusterManagerFailoverOnFinalizationLoop() throws Exception {
+        internalCluster().startClusterManagerOnlyNodes(3);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
         createIndexWithContent("index-test");
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.DISCONNECT);
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.DISCONNECT);
         internalCluster().setDisruptionScheme(networkDisruption);
 
         final List<String> snapshotNames = createNSnapshots(repoName, randomIntBetween(2, 5));
-        final String masterName = internalCluster().getMasterName();
-        blockMasterFromDeletingIndexNFile(repoName);
-        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromMasterClient(repoName, "snap-other");
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        blockClusterManagerFromDeletingIndexNFile(repoName);
+        final ActionFuture<CreateSnapshotResponse> snapshotThree = startFullSnapshotFromClusterManagerClient(repoName, "snap-other");
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
 
         final String snapshotOne = snapshotNames.get(0);
         final ActionFuture<AcknowledgedResponse> deleteSnapshotOne = startDeleteSnapshot(repoName, snapshotOne);
@@ -1088,7 +1099,7 @@ public void testMasterFailoverOnFinalizationLoop() throws Exception {
         networkDisruption.startDisrupting();
         ensureStableCluster(3, dataNode);
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         networkDisruption.stopDisrupting();
         ensureStableCluster(4);
 
@@ -1102,7 +1113,7 @@ public void testMasterFailoverOnFinalizationLoop() throws Exception {
     }
 
     public void testStatusMultipleSnapshotsMultipleRepos() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         // We're blocking a some of the snapshot threads when we block the first repo below so we have to make sure we have enough threads
         // left for the second concurrent snapshot.
         final String dataNode = startDataNodeWithLargeSnapshotPool();
@@ -1146,7 +1157,7 @@ public void testStatusMultipleSnapshotsMultipleRepos() throws Exception {
     }
 
     public void testInterleavedAcrossMultipleRepos() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         // We're blocking a some of the snapshot threads when we block the first repo below so we have to make sure we have enough threads
         // left for the second concurrent snapshot.
         final String dataNode = startDataNodeWithLargeSnapshotPool();
@@ -1180,10 +1191,10 @@ public void testInterleavedAcrossMultipleRepos() throws Exception {
         assertSuccessful(createSlowFuture3);
     }
 
-    public void testMasterFailoverAndMultipleQueuedUpSnapshotsAcrossTwoRepos() throws Exception {
+    public void testClusterManagerFailoverAndMultipleQueuedUpSnapshotsAcrossTwoRepos() throws Exception {
         disableRepoConsistencyCheck("This test corrupts the repository on purpose");
 
-        internalCluster().startMasterOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
+        internalCluster().startClusterManagerOnlyNodes(3, LARGE_SNAPSHOT_POOL_SETTINGS);
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final String otherRepoName = "other-test-repo";
@@ -1197,8 +1208,8 @@ public void testMasterFailoverAndMultipleQueuedUpSnapshotsAcrossTwoRepos() throw
 
         corruptIndexN(repoPath, getRepositoryData(repoName).getGenId());
 
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
-        blockMasterFromFinalizingSnapshotOnIndexFile(otherRepoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(otherRepoName);
 
         client().admin().cluster().prepareCreateSnapshot(repoName, "snapshot-blocked-1").setWaitForCompletion(false).get();
         client().admin().cluster().prepareCreateSnapshot(repoName, "snapshot-blocked-2").setWaitForCompletion(false).get();
@@ -1206,11 +1217,11 @@ public void testMasterFailoverAndMultipleQueuedUpSnapshotsAcrossTwoRepos() throw
         client().admin().cluster().prepareCreateSnapshot(otherRepoName, "snapshot-other-blocked-2").setWaitForCompletion(false).get();
 
         awaitNumberOfSnapshotsInProgress(4);
-        final String initialMaster = internalCluster().getMasterName();
-        waitForBlock(initialMaster, repoName, TimeValue.timeValueSeconds(30L));
-        waitForBlock(initialMaster, otherRepoName, TimeValue.timeValueSeconds(30L));
+        final String initialClusterManager = internalCluster().getClusterManagerName();
+        waitForBlock(initialClusterManager, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(initialClusterManager, otherRepoName, TimeValue.timeValueSeconds(30L));
 
-        internalCluster().stopCurrentMasterNode();
+        internalCluster().stopCurrentClusterManagerNode();
         ensureStableCluster(3, dataNode);
         awaitNoMoreRunningOperations();
 
@@ -1219,7 +1230,7 @@ public void testMasterFailoverAndMultipleQueuedUpSnapshotsAcrossTwoRepos() throw
     }
 
     public void testConcurrentOperationsLimit() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -1237,7 +1248,7 @@ public void testConcurrentOperationsLimit() throws Exception {
         );
 
         final List<String> snapshotNames = createNSnapshots(repoName, limitToTest + 1);
-        blockNodeOnAnyFiles(repoName, masterName);
+        blockNodeOnAnyFiles(repoName, clusterManagerName);
         int blockedSnapshots = 0;
         boolean blockedDelete = false;
         final List<ActionFuture<CreateSnapshotResponse>> snapshotFutures = new ArrayList<>();
@@ -1255,7 +1266,7 @@ public void testConcurrentOperationsLimit() throws Exception {
         if (blockedDelete) {
             awaitNDeletionsInProgress(1);
         }
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
 
         final String expectedFailureMessage = "Cannot start another operation, already running ["
             + limitToTest
@@ -1275,7 +1286,7 @@ public void testConcurrentOperationsLimit() throws Exception {
             assertThat(csen2.getMessage(), containsString(expectedFailureMessage));
         }
 
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         if (deleteFuture != null) {
             assertAcked(deleteFuture.get());
         }
@@ -1285,7 +1296,7 @@ public void testConcurrentOperationsLimit() throws Exception {
     }
 
     public void testConcurrentSnapshotWorksWithOldVersionRepo() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
@@ -1322,23 +1333,23 @@ public void testConcurrentSnapshotWorksWithOldVersionRepo() throws Exception {
     }
 
     public void testQueuedDeleteAfterFinalizationFailure() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
-        blockMasterFromFinalizingSnapshotOnIndexFile(repoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(repoName);
         final String snapshotName = "snap-1";
         final ActionFuture<CreateSnapshotResponse> snapshotFuture = startFullSnapshot(repoName, snapshotName);
-        waitForBlock(masterNode, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerNode, repoName, TimeValue.timeValueSeconds(30L));
         final ActionFuture<AcknowledgedResponse> deleteFuture = startDeleteSnapshot(repoName, snapshotName);
         awaitNDeletionsInProgress(1);
-        unblockNode(repoName, masterNode);
+        unblockNode(repoName, clusterManagerNode);
         assertAcked(deleteFuture.get());
         final SnapshotException sne = expectThrows(SnapshotException.class, snapshotFuture::actionGet);
         assertThat(sne.getCause().getMessage(), containsString("exception after block"));
     }
 
     public void testAbortNotStartedSnapshotWithoutIO() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -1365,7 +1376,7 @@ public void testAbortNotStartedSnapshotWithoutIO() throws Exception {
     }
 
     public void testStartWithSuccessfulShardSnapshotPendingFinalization() throws Exception {
-        final String masterName = internalCluster().startMasterOnlyNode();
+        final String clusterManagerName = internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "mock");
@@ -1373,18 +1384,18 @@ public void testStartWithSuccessfulShardSnapshotPendingFinalization() throws Exc
         createIndexWithContent("test-idx");
         createFullSnapshot(repoName, "first-snapshot");
 
-        blockMasterOnWriteIndexFile(repoName);
+        blockClusterManagerOnWriteIndexFile(repoName);
         final ActionFuture<CreateSnapshotResponse> blockedSnapshot = startFullSnapshot(repoName, "snap-blocked");
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         awaitNumberOfSnapshotsInProgress(1);
         blockNodeOnAnyFiles(repoName, dataNode);
         final ActionFuture<CreateSnapshotResponse> otherSnapshot = startFullSnapshot(repoName, "other-snapshot");
         awaitNumberOfSnapshotsInProgress(2);
         assertFalse(blockedSnapshot.isDone());
-        unblockNode(repoName, masterName);
+        unblockNode(repoName, clusterManagerName);
         awaitNumberOfSnapshotsInProgress(1);
 
-        awaitMasterFinishRepoOperations();
+        awaitClusterManagerFinishRepoOperations();
 
         unblockNode(repoName, dataNode);
         assertSuccessful(blockedSnapshot);
@@ -1416,14 +1427,14 @@ private List<String> createNSnapshots(String repoName, int count) {
         return snapshotNames;
     }
 
-    private ActionFuture<AcknowledgedResponse> startDeleteFromNonMasterClient(String repoName, String snapshotName) {
-        logger.info("--> deleting snapshot [{}] from repo [{}] from non master client", snapshotName, repoName);
-        return internalCluster().nonMasterClient().admin().cluster().prepareDeleteSnapshot(repoName, snapshotName).execute();
+    private ActionFuture<AcknowledgedResponse> startDeleteFromNonClusterManagerClient(String repoName, String snapshotName) {
+        logger.info("--> deleting snapshot [{}] from repo [{}] from non cluster-manager client", snapshotName, repoName);
+        return internalCluster().nonClusterManagerClient().admin().cluster().prepareDeleteSnapshot(repoName, snapshotName).execute();
     }
 
-    private ActionFuture<CreateSnapshotResponse> startFullSnapshotFromNonMasterClient(String repoName, String snapshotName) {
-        logger.info("--> creating full snapshot [{}] to repo [{}] from non master client", snapshotName, repoName);
-        return internalCluster().nonMasterClient()
+    private ActionFuture<CreateSnapshotResponse> startFullSnapshotFromNonClusterManagerClient(String repoName, String snapshotName) {
+        logger.info("--> creating full snapshot [{}] to repo [{}] from non cluster-manager client", snapshotName, repoName);
+        return internalCluster().nonClusterManagerClient()
             .admin()
             .cluster()
             .prepareCreateSnapshot(repoName, snapshotName)
@@ -1431,9 +1442,9 @@ private ActionFuture<CreateSnapshotResponse> startFullSnapshotFromNonMasterClien
             .execute();
     }
 
-    private ActionFuture<CreateSnapshotResponse> startFullSnapshotFromMasterClient(String repoName, String snapshotName) {
-        logger.info("--> creating full snapshot [{}] to repo [{}] from master client", snapshotName, repoName);
-        return internalCluster().masterClient()
+    private ActionFuture<CreateSnapshotResponse> startFullSnapshotFromClusterManagerClient(String repoName, String snapshotName) {
+        logger.info("--> creating full snapshot [{}] to repo [{}] from cluster-manager client", snapshotName, repoName);
+        return internalCluster().clusterManagerClient()
             .admin()
             .cluster()
             .prepareCreateSnapshot(repoName, snapshotName)
@@ -1453,8 +1464,8 @@ private void createIndexWithContent(String indexName, String nodeInclude, String
     private static boolean snapshotHasCompletedShard(String snapshot, SnapshotsInProgress snapshotsInProgress) {
         for (SnapshotsInProgress.Entry entry : snapshotsInProgress.entries()) {
             if (entry.snapshot().getSnapshotId().getName().equals(snapshot)) {
-                for (ObjectCursor<SnapshotsInProgress.ShardSnapshotStatus> shard : entry.shards().values()) {
-                    if (shard.value.state().completed()) {
+                for (final SnapshotsInProgress.ShardSnapshotStatus shard : entry.shards().values()) {
+                    if (shard.state().completed()) {
                         return true;
                     }
                 }
@@ -1488,18 +1499,18 @@ private static List<SnapshotInfo> currentSnapshots(String repoName) {
 
     private ActionFuture<AcknowledgedResponse> startAndBlockOnDeleteSnapshot(String repoName, String snapshotName)
         throws InterruptedException {
-        final String masterName = internalCluster().getMasterName();
-        blockNodeOnAnyFiles(repoName, masterName);
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        blockNodeOnAnyFiles(repoName, clusterManagerName);
         final ActionFuture<AcknowledgedResponse> fut = startDeleteSnapshot(repoName, snapshotName);
-        waitForBlock(masterName, repoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(clusterManagerName, repoName, TimeValue.timeValueSeconds(30L));
         return fut;
     }
 
     private ActionFuture<CreateSnapshotResponse> startAndBlockFailingFullSnapshot(String blockedRepoName, String snapshotName)
         throws InterruptedException {
-        blockMasterFromFinalizingSnapshotOnIndexFile(blockedRepoName);
+        blockClusterManagerFromFinalizingSnapshotOnIndexFile(blockedRepoName);
         final ActionFuture<CreateSnapshotResponse> fut = startFullSnapshot(blockedRepoName, snapshotName);
-        waitForBlock(internalCluster().getMasterName(), blockedRepoName, TimeValue.timeValueSeconds(30L));
+        waitForBlock(internalCluster().getClusterManagerName(), blockedRepoName, TimeValue.timeValueSeconds(30L));
         return fut;
     }
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/CorruptedBlobStoreRepositoryIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/CorruptedBlobStoreRepositoryIT.java
index c253f1a4f876e..fbf2acf7b08a6 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/CorruptedBlobStoreRepositoryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/CorruptedBlobStoreRepositoryIT.java
@@ -43,11 +43,11 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.IndexMetaDataGenerations;
 import org.opensearch.repositories.RepositoriesService;
@@ -205,7 +205,7 @@ public void testConcurrentlyChangeRepositoryContentsInBwCMode() throws Exception
             equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
         );
 
-        final Repository repository = internalCluster().getMasterNodeInstance(RepositoriesService.class).repository(repoName);
+        final Repository repository = internalCluster().getClusterManagerNodeInstance(RepositoriesService.class).repository(repoName);
 
         logger.info("--> move index-N blob to next generation");
         final RepositoryData repositoryData = getRepositoryData(repository);
@@ -215,7 +215,7 @@ public void testConcurrentlyChangeRepositoryContentsInBwCMode() throws Exception
         logger.info("--> verify index-N blob is found at the new location");
         assertThat(getRepositoryData(repository).getGenId(), is(beforeMoveGen + 1));
 
-        final SnapshotsService snapshotsService = internalCluster().getCurrentMasterNodeInstance(SnapshotsService.class);
+        final SnapshotsService snapshotsService = internalCluster().getCurrentClusterManagerNodeInstance(SnapshotsService.class);
         logger.info("--> wait for all listeners on snapshots service to be resolved to avoid snapshot task batching causing a conflict");
         assertBusy(() -> assertTrue(snapshotsService.assertAllListenersResolved()));
 
@@ -267,7 +267,8 @@ public void testFindDanglingLatestGeneration() throws Exception {
             equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
         );
 
-        final Repository repository = internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repoName);
+        final Repository repository = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class)
+            .repository(repoName);
 
         logger.info("--> move index-N blob to next generation");
         final RepositoryData repositoryData = getRepositoryData(repoName);
@@ -361,14 +362,14 @@ public void testHandlingMissingRootLevelSnapshotMetadata() throws Exception {
         Files.write(
             repo.resolve(BlobStoreRepository.INDEX_FILE_PREFIX + withoutVersions.getGenId()),
             BytesReference.toBytes(
-                BytesReference.bytes(withoutVersions.snapshotsToXContent(XContentFactory.jsonBuilder(), Version.CURRENT))
+                BytesReference.bytes(withoutVersions.snapshotsToXContent(MediaTypeRegistry.JSON.contentBuilder(), Version.CURRENT))
             ),
             StandardOpenOption.TRUNCATE_EXISTING
         );
 
         logger.info("--> verify that repo is assumed in old metadata format");
-        final SnapshotsService snapshotsService = internalCluster().getCurrentMasterNodeInstance(SnapshotsService.class);
-        final ThreadPool threadPool = internalCluster().getCurrentMasterNodeInstance(ThreadPool.class);
+        final SnapshotsService snapshotsService = internalCluster().getCurrentClusterManagerNodeInstance(SnapshotsService.class);
+        final ThreadPool threadPool = internalCluster().getCurrentClusterManagerNodeInstance(ThreadPool.class);
         assertThat(
             PlainActionFuture.get(
                 f -> threadPool.generic()
@@ -435,7 +436,8 @@ public void testMountCorruptedRepositoryData() throws Exception {
         );
 
         logger.info("--> corrupt index-N blob");
-        final Repository repository = internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repoName);
+        final Repository repository = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class)
+            .repository(repoName);
         final RepositoryData repositoryData = getRepositoryData(repoName);
         Files.write(repo.resolve("index-" + repositoryData.getGenId()), randomByteArrayOfLength(randomIntBetween(1, 100)));
 
@@ -444,7 +446,8 @@ public void testMountCorruptedRepositoryData() throws Exception {
 
         final String otherRepoName = "other-repo";
         createRepository(otherRepoName, "fs", Settings.builder().put("location", repo).put("compress", false));
-        final Repository otherRepo = internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(otherRepoName);
+        final Repository otherRepo = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class)
+            .repository(otherRepoName);
 
         logger.info("--> verify loading repository data from newly mounted repository throws RepositoryException");
         expectThrows(RepositoryException.class, () -> getRepositoryData(otherRepo));
@@ -519,7 +522,7 @@ public void testRepairBrokenShardGenerations() throws Exception {
         Files.write(
             repoPath.resolve(BlobStoreRepository.INDEX_FILE_PREFIX + repositoryData1.getGenId()),
             BytesReference.toBytes(
-                BytesReference.bytes(brokenRepoData.snapshotsToXContent(XContentFactory.jsonBuilder(), Version.CURRENT))
+                BytesReference.bytes(brokenRepoData.snapshotsToXContent(MediaTypeRegistry.JSON.contentBuilder(), Version.CURRENT))
             ),
             StandardOpenOption.TRUNCATE_EXISTING
         );
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/DedicatedClusterSnapshotRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/DedicatedClusterSnapshotRestoreIT.java
index 47d57e1260b5f..86d5d21adbadd 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/DedicatedClusterSnapshotRestoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/DedicatedClusterSnapshotRestoreIT.java
@@ -32,11 +32,7 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.IntHashSet;
-import com.carrotsearch.hppc.IntSet;
-
 import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
@@ -59,24 +55,26 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.index.seqno.RetentionLeaseActions;
 import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.node.Node;
@@ -86,15 +84,14 @@
 import org.opensearch.rest.AbstractRestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.admin.cluster.RestClusterStateAction;
 import org.opensearch.rest.action.admin.cluster.RestGetRepositoriesAction;
 import org.opensearch.snapshots.mockstore.MockRepository;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.TestCustomMetadata;
-import org.opensearch.test.disruption.BusyMasterServiceDisruption;
+import org.opensearch.test.disruption.BusyClusterManagerServiceDisruption;
 import org.opensearch.test.disruption.ServiceDisruptionScheme;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.test.transport.MockTransportService;
@@ -115,8 +112,10 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -124,7 +123,7 @@
 import java.util.function.Consumer;
 
 import static org.opensearch.index.seqno.RetentionLeaseActions.RETAIN_ALL;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertFutureThrows;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertRequestBuilderThrows;
@@ -482,8 +481,8 @@ public void testSnapshotWithStuckNode() throws Exception {
         try {
             assertAcked(deleteSnapshotResponseFuture.actionGet());
         } catch (SnapshotMissingException ex) {
-            // When master node is closed during this test, it sometime manages to delete the snapshot files before
-            // completely stopping. In this case the retried delete snapshot operation on the new master can fail
+            // When cluster-manager node is closed during this test, it sometime manages to delete the snapshot files before
+            // completely stopping. In this case the retried delete snapshot operation on the new cluster-manager can fail
             // with SnapshotMissingException
         }
 
@@ -738,7 +737,7 @@ public boolean clearData(String nodeName) {
 
         ensureGreen("test-idx");
 
-        IntSet reusedShards = new IntHashSet();
+        final Set<Integer> reusedShards = new HashSet<>();
         List<RecoveryState> recoveryStates = client().admin()
             .indices()
             .prepareRecoveries("test-idx")
@@ -759,8 +758,8 @@ public void testRegistrationFailure() {
         logger.info("--> start first node");
         internalCluster().startNode();
         logger.info("--> start second node");
-        // Make sure the first node is elected as master
-        internalCluster().startNode(nonMasterNode());
+        // Make sure the first node is elected as cluster-manager
+        internalCluster().startNode(nonClusterManagerNode());
         // Register mock repositories
         for (int i = 0; i < 5; i++) {
             clusterAdmin().preparePutRepository("test-repo" + i)
@@ -835,9 +834,9 @@ public void sendResponse(RestResponse response) {
         }
     }
 
-    public void testMasterShutdownDuringSnapshot() throws Exception {
-        logger.info("-->  starting two master nodes and two data nodes");
-        internalCluster().startMasterOnlyNodes(2);
+    public void testClusterManagerShutdownDuringSnapshot() throws Exception {
+        logger.info("-->  starting two cluster-manager nodes and two data nodes");
+        internalCluster().startClusterManagerOnlyNodes(2);
         internalCluster().startDataOnlyNodes(2);
 
         final Path repoPath = randomRepoPath();
@@ -859,8 +858,8 @@ public void testMasterShutdownDuringSnapshot() throws Exception {
             .setIndices("test-idx")
             .get();
 
-        logger.info("--> stopping master node");
-        internalCluster().stopCurrentMasterNode();
+        logger.info("--> stopping cluster-manager node");
+        internalCluster().stopCurrentClusterManagerNode();
 
         logger.info("--> wait until the snapshot is done");
 
@@ -873,9 +872,9 @@ public void testMasterShutdownDuringSnapshot() throws Exception {
         assertEquals(0, snapshotInfo.failedShards());
     }
 
-    public void testMasterAndDataShutdownDuringSnapshot() throws Exception {
-        logger.info("-->  starting three master nodes and two data nodes");
-        internalCluster().startMasterOnlyNodes(3);
+    public void testClusterManagerAndDataShutdownDuringSnapshot() throws Exception {
+        logger.info("-->  starting three cluster-manager nodes and two data nodes");
+        internalCluster().startClusterManagerOnlyNodes(3);
         internalCluster().startDataOnlyNodes(2);
 
         final Path repoPath = randomRepoPath();
@@ -890,7 +889,7 @@ public void testMasterAndDataShutdownDuringSnapshot() throws Exception {
         final int numberOfShards = getNumShards("test-idx").numPrimaries;
         logger.info("number of shards: {}", numberOfShards);
 
-        final String masterNode = blockMasterFromFinalizingSnapshotOnSnapFile("test-repo");
+        final String clusterManagerNode = blockClusterManagerFromFinalizingSnapshotOnSnapFile("test-repo");
         final String dataNode = blockNodeWithIndex("test-repo", "test-idx");
 
         dataNodeClient().admin()
@@ -902,8 +901,8 @@ public void testMasterAndDataShutdownDuringSnapshot() throws Exception {
 
         logger.info("--> stopping data node {}", dataNode);
         stopNode(dataNode);
-        logger.info("--> stopping master node {} ", masterNode);
-        internalCluster().stopCurrentMasterNode();
+        logger.info("--> stopping cluster-manager node {} ", clusterManagerNode);
+        internalCluster().stopCurrentClusterManagerNode();
 
         logger.info("--> wait until the snapshot is done");
 
@@ -925,8 +924,8 @@ public void testMasterAndDataShutdownDuringSnapshot() throws Exception {
      * the cluster.
      */
     public void testRestoreShrinkIndex() throws Exception {
-        logger.info("-->  starting a master node and a data node");
-        internalCluster().startMasterOnlyNode();
+        logger.info("-->  starting a cluster-manager node and a data node");
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
 
         final String repo = "test-repo";
@@ -1143,9 +1142,9 @@ public void testDeduplicateIndexMetadata() throws Exception {
         assertThat(snapshot3IndexMetaFiles, hasSize(1)); // should have deleted the metadata blob referenced by the first two snapshots
     }
 
-    public void testDataNodeRestartWithBusyMasterDuringSnapshot() throws Exception {
-        logger.info("-->  starting a master node and two data nodes");
-        internalCluster().startMasterOnlyNode();
+    public void testDataNodeRestartWithBusyClusterManagerDuringSnapshot() throws Exception {
+        logger.info("-->  starting a cluster-manager node and two data nodes");
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNodes(2);
         final Path repoPath = randomRepoPath();
         createRepository("test-repo", "mock", repoPath);
@@ -1157,9 +1156,9 @@ public void testDataNodeRestartWithBusyMasterDuringSnapshot() throws Exception {
 
         final String dataNode = blockNodeWithIndex("test-repo", "test-idx");
         logger.info("-->  snapshot");
-        ServiceDisruptionScheme disruption = new BusyMasterServiceDisruption(random(), Priority.HIGH);
+        ServiceDisruptionScheme disruption = new BusyClusterManagerServiceDisruption(random(), Priority.HIGH);
         setDisruptionScheme(disruption);
-        client(internalCluster().getMasterName()).admin()
+        client(internalCluster().getClusterManagerName()).admin()
             .cluster()
             .prepareCreateSnapshot("test-repo", "test-snap")
             .setWaitForCompletion(false)
@@ -1200,8 +1199,8 @@ public void testDataNodeRestartWithBusyMasterDuringSnapshot() throws Exception {
     }
 
     public void testDataNodeRestartAfterShardSnapshotFailure() throws Exception {
-        logger.info("-->  starting a master node and two data nodes");
-        internalCluster().startMasterOnlyNode();
+        logger.info("-->  starting a cluster-manager node and two data nodes");
+        internalCluster().startClusterManagerOnlyNode();
         final List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
         final Path repoPath = randomRepoPath();
         createRepository("test-repo", "mock", repoPath);
@@ -1213,7 +1212,7 @@ public void testDataNodeRestartAfterShardSnapshotFailure() throws Exception {
 
         blockAllDataNodes("test-repo");
         logger.info("-->  snapshot");
-        client(internalCluster().getMasterName()).admin()
+        client(internalCluster().getClusterManagerName()).admin()
             .cluster()
             .prepareCreateSnapshot("test-repo", "test-snap")
             .setWaitForCompletion(false)
@@ -1323,7 +1322,7 @@ public void testRetentionLeasesClearedOnRestore() throws Exception {
     }
 
     public void testAbortWaitsOnDataNode() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNodeName = internalCluster().startDataOnlyNode();
         final String indexName = "test-index";
         createIndex(indexName);
@@ -1375,7 +1374,7 @@ public void onRequestSent(
     }
 
     public void testPartialSnapshotAllShardsMissing() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final String dataNode = internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "fs");
@@ -1393,17 +1392,17 @@ public void testPartialSnapshotAllShardsMissing() throws Exception {
      * correctly by testing a snapshot name collision.
      */
     public void testCreateSnapshotLegacyPath() throws Exception {
-        final String masterNode = internalCluster().startMasterOnlyNode();
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoName = "test-repo";
         createRepository(repoName, "fs");
         createIndex("some-index");
 
-        final SnapshotsService snapshotsService = internalCluster().getMasterNodeInstance(SnapshotsService.class);
+        final SnapshotsService snapshotsService = internalCluster().getClusterManagerNodeInstance(SnapshotsService.class);
         final Snapshot snapshot1 = PlainActionFuture.get(
             f -> snapshotsService.createSnapshotLegacy(new CreateSnapshotRequest(repoName, "snap-1"), f)
         );
-        awaitNoMoreRunningOperations(masterNode);
+        awaitNoMoreRunningOperations(clusterManagerNode);
 
         final InvalidSnapshotNameException sne = expectThrows(
             InvalidSnapshotNameException.class,
@@ -1425,7 +1424,7 @@ public void testCreateSnapshotLegacyPath() throws Exception {
     }
 
     public void testSnapshotDeleteRelocatingPrimaryIndex() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         final List<String> dataNodes = internalCluster().startDataOnlyNodes(2);
         final String repoName = "test-repo";
         createRepository(repoName, "fs");
@@ -1475,6 +1474,31 @@ public void testSnapshotDeleteRelocatingPrimaryIndex() throws Exception {
         logger.info("--> done");
     }
 
+    public void testIndexDeletionDuringSnapshotCreationInQueue() throws Exception {
+        assertAcked(prepareCreate("test-idx", 1, indexSettingsNoReplicas(1)));
+        ensureGreen();
+        indexRandomDocs("test-idx", 100);
+        createRepository("test-repo", "fs");
+        createSnapshot("test-repo", "test-snap", Collections.singletonList("test-idx"));
+
+        logger.info("--> create snapshot to be deleted and then delete");
+        createSnapshot("test-repo", "test-snap-delete", Collections.singletonList("test-idx"));
+        clusterAdmin().prepareDeleteSnapshot("test-repo", "test-snap-delete").execute();
+
+        logger.info("--> create snapshot before index deletion during above snapshot deletion");
+        clusterAdmin().prepareCreateSnapshot("test-repo", "test-snap-2")
+            .setWaitForCompletion(false)
+            .setPartial(true)
+            .setIndices("test-idx")
+            .get();
+
+        logger.info("delete index during snapshot creation");
+        assertAcked(admin().indices().prepareDelete("test-idx"));
+
+        clusterAdmin().prepareRestoreSnapshot("test-repo", "test-snap").get();
+        ensureGreen("test-idx");
+    }
+
     private long calculateTotalFilesSize(List<Path> files) {
         return files.stream().mapToLong(f -> {
             try {
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/DeleteSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/DeleteSnapshotIT.java
new file mode 100644
index 0000000000000..864779f86caf3
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/DeleteSnapshotIT.java
@@ -0,0 +1,351 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.snapshots;
+
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.remotestore.RemoteStoreBaseIntegTestCase;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Stream;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.comparesEqualTo;
+import static org.hamcrest.Matchers.is;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class DeleteSnapshotIT extends AbstractSnapshotIntegTestCase {
+
+    private static final String REMOTE_REPO_NAME = "remote-store-repo-name";
+
+    public void testDeleteSnapshot() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "fs", snapshotRepoPath);
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == 0);
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == 1);
+
+        assertAcked(startDeleteSnapshot(snapshotRepoName, snapshot).get());
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == 0);
+    }
+
+    public void testDeleteShallowCopySnapshot() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy());
+
+        final String indexName = "index-1";
+        createIndexWithRandomDocs(indexName, randomIntBetween(5, 10));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        final String shallowSnapshot = "shallow-snapshot";
+        createFullSnapshot(snapshotRepoName, shallowSnapshot);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == 1);
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == 1);
+
+        assertAcked(startDeleteSnapshot(snapshotRepoName, shallowSnapshot).get());
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == 0);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == 0);
+    }
+
+    // Deleting multiple shallow copy snapshots as part of single delete call with repo having only shallow copy snapshots.
+    public void testDeleteMultipleShallowCopySnapshotsCase1() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        final Client clusterManagerClient = internalCluster().clusterManagerClient();
+        ensureStableCluster(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+        final String testIndex = "index-test";
+        createIndexWithContent(testIndex);
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        // Creating some shallow copy snapshots
+        int totalShallowCopySnapshotsCount = randomIntBetween(4, 10);
+        List<String> shallowCopySnapshots = createNSnapshots(snapshotRepoName, totalShallowCopySnapshotsCount);
+        List<String> snapshotsToBeDeleted = shallowCopySnapshots.subList(0, randomIntBetween(2, totalShallowCopySnapshotsCount));
+        int tobeDeletedSnapshotsCount = snapshotsToBeDeleted.size();
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalShallowCopySnapshotsCount);
+        // Deleting subset of shallow copy snapshots
+        assertAcked(
+            clusterManagerClient.admin()
+                .cluster()
+                .prepareDeleteSnapshot(snapshotRepoName, snapshotsToBeDeleted.toArray(new String[0]))
+                .get()
+        );
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalShallowCopySnapshotsCount - tobeDeletedSnapshotsCount);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount
+            - tobeDeletedSnapshotsCount);
+    }
+
+    // Deleting multiple shallow copy snapshots as part of single delete call with both partial and full copy snapshot present in the repo
+    // And then deleting multiple full copy snapshots as part of single delete call with both partial and shallow copy snapshots present in
+    // the repo
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8610")
+    public void testDeleteMultipleShallowCopySnapshotsCase2() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        final String dataNode = internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        ensureStableCluster(2);
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+        final String testIndex = "index-test";
+        createIndexWithContent(testIndex);
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        // Creating a partial shallow copy snapshot
+        final String snapshot = "snapshot";
+        blockNodeWithIndex(snapshotRepoName, testIndex);
+        blockDataNode(snapshotRepoName, dataNode);
+
+        final Client clusterManagerClient = internalCluster().clusterManagerClient();
+        final ActionFuture<CreateSnapshotResponse> snapshotFuture = clusterManagerClient.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepoName, snapshot)
+            .setWaitForCompletion(true)
+            .execute();
+
+        awaitNumberOfSnapshotsInProgress(1);
+        waitForBlock(dataNode, snapshotRepoName, TimeValue.timeValueSeconds(30L));
+        internalCluster().restartNode(dataNode);
+        assertThat(snapshotFuture.get().getSnapshotInfo().state(), is(SnapshotState.PARTIAL));
+
+        unblockAllDataNodes(snapshotRepoName);
+
+        ensureStableCluster(2, clusterManagerNode);
+
+        // Creating some shallow copy snapshots
+        int totalShallowCopySnapshotsCount = randomIntBetween(4, 10);
+        List<String> shallowCopySnapshots = createNSnapshots(snapshotRepoName, totalShallowCopySnapshotsCount);
+        List<String> shallowCopySnapshotsToBeDeleted = shallowCopySnapshots.subList(0, randomIntBetween(2, totalShallowCopySnapshotsCount));
+        int tobeDeletedShallowCopySnapshotsCount = shallowCopySnapshotsToBeDeleted.size();
+        totalShallowCopySnapshotsCount += 1; // Adding partial shallow snapshot here
+        // Updating the snapshot repository flag to disable shallow snapshots
+        createRepository(snapshotRepoName, "mock", snapshotRepoPath);
+        // Creating some full copy snapshots
+        int totalFullCopySnapshotsCount = randomIntBetween(4, 10);
+        List<String> fullCopySnapshots = createNSnapshots(snapshotRepoName, totalFullCopySnapshotsCount);
+        List<String> fullCopySnapshotsToBeDeleted = fullCopySnapshots.subList(0, randomIntBetween(2, totalFullCopySnapshotsCount));
+        int tobeDeletedFullCopySnapshotsCount = fullCopySnapshotsToBeDeleted.size();
+
+        int totalSnapshotsCount = totalFullCopySnapshotsCount + totalShallowCopySnapshotsCount;
+
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalSnapshotsCount);
+        // Deleting subset of shallow copy snapshots
+        assertAcked(
+            clusterManagerClient.admin()
+                .cluster()
+                .prepareDeleteSnapshot(snapshotRepoName, shallowCopySnapshotsToBeDeleted.toArray(new String[0]))
+                .get()
+        );
+        totalSnapshotsCount -= tobeDeletedShallowCopySnapshotsCount;
+        totalShallowCopySnapshotsCount -= tobeDeletedShallowCopySnapshotsCount;
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalSnapshotsCount);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+
+        // Deleting subset of full copy snapshots
+        assertAcked(
+            clusterManagerClient.admin()
+                .cluster()
+                .prepareDeleteSnapshot(snapshotRepoName, fullCopySnapshotsToBeDeleted.toArray(new String[0]))
+                .get()
+        );
+        totalSnapshotsCount -= tobeDeletedFullCopySnapshotsCount;
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalSnapshotsCount);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+    }
+
+    // Deleting subset of shallow and full copy snapshots as part of single delete call and then deleting all snapshots in the repo.
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8610")
+    public void testDeleteMultipleShallowCopySnapshotsCase3() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        final Client clusterManagerClient = internalCluster().clusterManagerClient();
+        ensureStableCluster(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+
+        final String testIndex = "index-test";
+        createIndexWithContent(testIndex);
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        // Creating some shallow copy snapshots
+        int totalShallowCopySnapshotsCount = randomIntBetween(4, 10);
+        List<String> shallowCopySnapshots = createNSnapshots(snapshotRepoName, totalShallowCopySnapshotsCount);
+        List<String> shallowCopySnapshotsToBeDeleted = shallowCopySnapshots.subList(0, randomIntBetween(2, totalShallowCopySnapshotsCount));
+        int tobeDeletedShallowCopySnapshotsCount = shallowCopySnapshotsToBeDeleted.size();
+        // Updating the snapshot repository flag to disable shallow snapshots
+        createRepository(snapshotRepoName, "mock", snapshotRepoPath);
+        // Creating some full copy snapshots
+        int totalFullCopySnapshotsCount = randomIntBetween(4, 10);
+        List<String> fullCopySnapshots = createNSnapshots(snapshotRepoName, totalFullCopySnapshotsCount);
+        List<String> fullCopySnapshotsToBeDeleted = fullCopySnapshots.subList(0, randomIntBetween(2, totalFullCopySnapshotsCount));
+        int tobeDeletedFullCopySnapshotsCount = fullCopySnapshotsToBeDeleted.size();
+
+        int totalSnapshotsCount = totalFullCopySnapshotsCount + totalShallowCopySnapshotsCount;
+
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalSnapshotsCount);
+        // Deleting subset of shallow copy snapshots and full copy snapshots
+        assertAcked(
+            clusterManagerClient.admin()
+                .cluster()
+                .prepareDeleteSnapshot(
+                    snapshotRepoName,
+                    Stream.concat(shallowCopySnapshotsToBeDeleted.stream(), fullCopySnapshotsToBeDeleted.stream()).toArray(String[]::new)
+                )
+                .get()
+        );
+        totalSnapshotsCount -= (tobeDeletedShallowCopySnapshotsCount + tobeDeletedFullCopySnapshotsCount);
+        totalShallowCopySnapshotsCount -= tobeDeletedShallowCopySnapshotsCount;
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == totalSnapshotsCount);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == totalShallowCopySnapshotsCount);
+
+        // Deleting all the remaining snapshots
+        assertAcked(clusterManagerClient.admin().cluster().prepareDeleteSnapshot(snapshotRepoName, "*").get());
+        assert (getRepositoryData(snapshotRepoName).getSnapshotIds().size() == 0);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME).length == 0);
+    }
+
+    public void testRemoteStoreCleanupForDeletedIndex() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used in the test");
+        final Path remoteStoreRepoPath = randomRepoPath();
+        internalCluster().startClusterManagerOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        internalCluster().startDataOnlyNode(remoteStoreClusterSettings(REMOTE_REPO_NAME, remoteStoreRepoPath));
+        final Client clusterManagerClient = internalCluster().clusterManagerClient();
+        ensureStableCluster(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        final Path snapshotRepoPath = randomRepoPath();
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy(snapshotRepoPath));
+
+        final String testIndex = "index-test";
+        createIndexWithContent(testIndex);
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        indexRandomDocs(remoteStoreEnabledIndexName, randomIntBetween(5, 10));
+
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(remoteStoreEnabledIndexName)
+            .get()
+            .getSetting(remoteStoreEnabledIndexName, IndexMetadata.SETTING_INDEX_UUID);
+
+        logger.info("--> create two remote index shallow snapshots");
+        List<String> shallowCopySnapshots = createNSnapshots(snapshotRepoName, 2);
+
+        String[] lockFiles = getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME);
+        assert (lockFiles.length == 2) : "lock files are " + Arrays.toString(lockFiles);
+
+        // delete the giremote store index
+        assertAcked(client().admin().indices().prepareDelete(remoteStoreEnabledIndexName));
+
+        logger.info("--> delete snapshot 1");
+        AcknowledgedResponse deleteSnapshotResponse = clusterManagerClient.admin()
+            .cluster()
+            .prepareDeleteSnapshot(snapshotRepoName, shallowCopySnapshots.get(0))
+            .get();
+        assertAcked(deleteSnapshotResponse);
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreEnabledIndexName, REMOTE_REPO_NAME, indexUUID);
+        assert (lockFiles.length == 1) : "lock files are " + Arrays.toString(lockFiles);
+
+        logger.info("--> delete snapshot 2");
+        deleteSnapshotResponse = clusterManagerClient.admin()
+            .cluster()
+            .prepareDeleteSnapshot(snapshotRepoName, shallowCopySnapshots.get(1))
+            .get();
+        assertAcked(deleteSnapshotResponse);
+
+        Path indexPath = Path.of(String.valueOf(remoteStoreRepoPath), indexUUID);
+        // Delete is async. Give time for it
+        assertBusy(() -> {
+            try {
+                assertThat(RemoteStoreBaseIntegTestCase.getFileCount(indexPath), comparesEqualTo(0));
+            } catch (Exception e) {}
+        }, 30, TimeUnit.SECONDS);
+    }
+
+    private List<String> createNSnapshots(String repoName, int count) {
+        final List<String> snapshotNames = new ArrayList<>(count);
+        final String prefix = "snap-" + UUIDs.randomBase64UUID(random()).toLowerCase(Locale.ROOT) + "-";
+        for (int i = 0; i < count; i++) {
+            final String name = prefix + i;
+            createFullSnapshot(repoName, name);
+            snapshotNames.add(name);
+        }
+        logger.info("--> created {} in [{}]", snapshotNames, repoName);
+        return snapshotNames;
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/MetadataLoadingDuringSnapshotRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/MetadataLoadingDuringSnapshotRestoreIT.java
index 608a439b40fec..b19ba9f5862a7 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/MetadataLoadingDuringSnapshotRestoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/MetadataLoadingDuringSnapshotRestoreIT.java
@@ -41,7 +41,8 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
@@ -49,7 +50,6 @@
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
 import org.opensearch.repositories.RepositoryData;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.snapshots.mockstore.MockRepository;
 
 import java.io.IOException;
@@ -198,8 +198,8 @@ private void assertIndexMetadataLoads(final String snapshot, final String index,
     }
 
     private CountingMockRepository getCountingMockRepository() {
-        String master = internalCluster().getMasterName();
-        RepositoriesService repositoriesService = internalCluster().getInstance(RepositoriesService.class, master);
+        String clusterManager = internalCluster().getClusterManagerName();
+        RepositoriesService repositoriesService = internalCluster().getInstance(RepositoriesService.class, clusterManager);
         Repository repository = repositoriesService.repository("repository");
         assertThat(repository, instanceOf(CountingMockRepository.class));
         return (CountingMockRepository) repository;
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/MultiClusterRepoAccessIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/MultiClusterRepoAccessIT.java
index 2b2b656d5dd0e..1c46e37dea93a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/MultiClusterRepoAccessIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/MultiClusterRepoAccessIT.java
@@ -33,15 +33,15 @@
 
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.repositories.RepositoryException;
 import org.opensearch.snapshots.mockstore.MockRepository;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockHttpTransport;
 import org.opensearch.test.NodeConfigurationSource;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.nio.MockNioTransportPlugin;
 import org.junit.After;
@@ -107,13 +107,13 @@ public void stopSecondCluster() throws IOException {
     }
 
     public void testConcurrentDeleteFromOtherCluster() throws InterruptedException {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
         final String repoNameOnFirstCluster = "test-repo";
         final String repoNameOnSecondCluster = randomBoolean() ? "test-repo" : "other-repo";
         createRepository(repoNameOnFirstCluster, "fs", repoPath);
 
-        secondCluster.startMasterOnlyNode();
+        secondCluster.startClusterManagerOnlyNode();
         secondCluster.startDataOnlyNode();
         secondCluster.client()
             .admin()
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/RemoteIndexSnapshotStatusApiIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/RemoteIndexSnapshotStatusApiIT.java
new file mode 100644
index 0000000000000..8e2580aba1745
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/RemoteIndexSnapshotStatusApiIT.java
@@ -0,0 +1,206 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.snapshots;
+
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.action.admin.cluster.snapshots.status.SnapshotIndexShardStage;
+import org.opensearch.action.admin.cluster.snapshots.status.SnapshotIndexShardStatus;
+import org.opensearch.action.admin.cluster.snapshots.status.SnapshotStatus;
+import org.opensearch.cluster.SnapshotsInProgress;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.Before;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.is;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class RemoteIndexSnapshotStatusApiIT extends AbstractSnapshotIntegTestCase {
+
+    protected Path absolutePath;
+    final String remoteStoreRepoName = "remote-store-repo-name";
+
+    @Before
+    public void setup() {
+        absolutePath = randomRepoPath().toAbsolutePath();
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(ThreadPool.ESTIMATED_TIME_INTERVAL_SETTING.getKey(), 0) // We have tests that check by-timestamp order
+            .put(remoteStoreClusterSettings(remoteStoreRepoName, absolutePath))
+            .build();
+    }
+
+    public void testStatusAPICallForShallowCopySnapshot() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used for the test");
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNodes(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy());
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        ensureGreen();
+
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            index(remoteStoreEnabledIndexName, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 1);
+
+        final SnapshotStatus snapshotStatus = getSnapshotStatus(snapshotRepoName, snapshot);
+        assertThat(snapshotStatus.getState(), is(SnapshotsInProgress.State.SUCCESS));
+
+        // Validating that the incremental file count and incremental file size is zero for shallow copy
+        final SnapshotIndexShardStatus shallowSnapshotShardState = stateFirstShard(snapshotStatus, remoteStoreEnabledIndexName);
+        assertThat(shallowSnapshotShardState.getStage(), is(SnapshotIndexShardStage.DONE));
+        assertThat(shallowSnapshotShardState.getStats().getTotalFileCount(), greaterThan(0));
+        assertThat(shallowSnapshotShardState.getStats().getTotalSize(), greaterThan(0L));
+        assertThat(shallowSnapshotShardState.getStats().getIncrementalFileCount(), is(0));
+        assertThat(shallowSnapshotShardState.getStats().getIncrementalSize(), is(0L));
+    }
+
+    public void testStatusAPIStatsForBackToBackShallowSnapshot() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used for the test");
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNodes(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy());
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        ensureGreen();
+
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            index(remoteStoreEnabledIndexName, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+
+        createFullSnapshot(snapshotRepoName, "test-snap-1");
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 1);
+
+        SnapshotStatus snapshotStatus = getSnapshotStatus(snapshotRepoName, "test-snap-1");
+        assertThat(snapshotStatus.getState(), is(SnapshotsInProgress.State.SUCCESS));
+
+        SnapshotIndexShardStatus shallowSnapshotShardState = stateFirstShard(snapshotStatus, remoteStoreEnabledIndexName);
+        assertThat(shallowSnapshotShardState.getStage(), is(SnapshotIndexShardStage.DONE));
+        final int totalFileCount = shallowSnapshotShardState.getStats().getTotalFileCount();
+        final long totalSize = shallowSnapshotShardState.getStats().getTotalSize();
+        final int incrementalFileCount = shallowSnapshotShardState.getStats().getIncrementalFileCount();
+        final long incrementalSize = shallowSnapshotShardState.getStats().getIncrementalSize();
+
+        createFullSnapshot(snapshotRepoName, "test-snap-2");
+        assert (getLockFilesInRemoteStore(remoteStoreEnabledIndexName, remoteStoreRepoName).length == 2);
+
+        snapshotStatus = getSnapshotStatus(snapshotRepoName, "test-snap-2");
+        assertThat(snapshotStatus.getState(), is(SnapshotsInProgress.State.SUCCESS));
+        shallowSnapshotShardState = stateFirstShard(snapshotStatus, remoteStoreEnabledIndexName);
+        assertThat(shallowSnapshotShardState.getStats().getTotalFileCount(), equalTo(totalFileCount));
+        assertThat(shallowSnapshotShardState.getStats().getTotalSize(), equalTo(totalSize));
+        assertThat(shallowSnapshotShardState.getStats().getIncrementalFileCount(), equalTo(incrementalFileCount));
+        assertThat(shallowSnapshotShardState.getStats().getIncrementalSize(), equalTo(incrementalSize));
+    }
+
+    public void testStatusAPICallInProgressShallowSnapshot() throws Exception {
+        disableRepoConsistencyCheck("Remote store repository is being used for the test");
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNodes(2);
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy().put("block_on_data", true));
+
+        final String remoteStoreEnabledIndexName = "remote-index-1";
+        final Settings remoteStoreEnabledIndexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreEnabledIndexName, remoteStoreEnabledIndexSettings);
+        ensureGreen();
+
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            index(remoteStoreEnabledIndexName, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+
+        logger.info("--> snapshot");
+        ActionFuture<CreateSnapshotResponse> createSnapshotResponseActionFuture = startFullSnapshot(snapshotRepoName, "test-snap");
+
+        logger.info("--> wait for data nodes to get blocked");
+        awaitNumberOfSnapshotsInProgress(1);
+        assertEquals(
+            SnapshotsInProgress.State.STARTED,
+            client().admin()
+                .cluster()
+                .prepareSnapshotStatus(snapshotRepoName)
+                .setSnapshots("test-snap")
+                .get()
+                .getSnapshots()
+                .get(0)
+                .getState()
+        );
+
+        logger.info("--> unblock all data nodes");
+        unblockAllDataNodes(snapshotRepoName);
+
+        logger.info("--> wait for snapshot to finish");
+        createSnapshotResponseActionFuture.actionGet();
+    }
+
+    private static SnapshotIndexShardStatus stateFirstShard(SnapshotStatus snapshotStatus, String indexName) {
+        return snapshotStatus.getIndices().get(indexName).getShards().get(0);
+    }
+
+    private static SnapshotStatus getSnapshotStatus(String repoName, String snapshotName) {
+        try {
+            return client().admin().cluster().prepareSnapshotStatus(repoName).setSnapshots(snapshotName).get().getSnapshots().get(0);
+        } catch (SnapshotMissingException e) {
+            throw new AssertionError(e);
+        }
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoriesIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoriesIT.java
index 662e97dd84fda..dd40c77ba918d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoriesIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoriesIT.java
@@ -35,17 +35,20 @@
 import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesResponse;
 import org.opensearch.action.admin.cluster.repositories.verify.VerifyRepositoryResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.RepositoryException;
 import org.opensearch.repositories.RepositoryVerificationException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.snapshots.mockstore.MockRepository;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.threadpool.ThreadPool;
@@ -71,7 +74,7 @@ public void testRepositoryCreation() throws Exception {
         logger.info("--> verify the repository");
         int numberOfFiles = FileSystemUtils.files(location).length;
         VerifyRepositoryResponse verifyRepositoryResponse = client.admin().cluster().prepareVerifyRepository("test-repo-1").get();
-        assertThat(verifyRepositoryResponse.getNodes().size(), equalTo(cluster().numDataAndMasterNodes()));
+        assertThat(verifyRepositoryResponse.getNodes().size(), equalTo(cluster().numDataAndClusterManagerNodes()));
 
         logger.info("--> verify that we didn't leave any files as a result of verification");
         assertThat(FileSystemUtils.files(location).length, equalTo(numberOfFiles));
@@ -157,7 +160,7 @@ public void testResidualStaleIndicesAreDeletedByConsecutiveDelete() throws Excep
         createFullSnapshot(repositoryName, snapshotToBeDeletedLastName);
 
         // Create more snapshots to be deleted in bulk
-        int maxThreadsForSnapshotDeletion = internalCluster().getMasterNodeInstance(ThreadPool.class)
+        int maxThreadsForSnapshotDeletion = internalCluster().getClusterManagerNodeInstance(ThreadPool.class)
             .info(ThreadPool.Names.SNAPSHOT)
             .getMax();
         for (int i = 1; i <= maxThreadsForSnapshotDeletion + 1; i++) {
@@ -177,15 +180,15 @@ public void testResidualStaleIndicesAreDeletedByConsecutiveDelete() throws Excep
 
         // Make repository to throw exception when trying to delete stale indices
         // This will make sure stale indices stays in repository after snapshot delete
-        String masterNode = internalCluster().getMasterName();
-        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, masterNode).repository("test-repo"))
+        String clusterManagerNode = internalCluster().getClusterManagerName();
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerNode).repository("test-repo"))
             .setThrowExceptionWhileDelete(true);
 
         logger.info("--> delete the bulk of the snapshots");
         client.admin().cluster().prepareDeleteSnapshot(repositoryName, bulkSnapshotsPattern).get();
 
         // Make repository to work normally
-        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, masterNode).repository("test-repo"))
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerNode).repository("test-repo"))
             .setThrowExceptionWhileDelete(false);
 
         // This snapshot should delete last snapshot's residual stale indices as well
@@ -328,4 +331,125 @@ public void testRepositoryVerification() throws Exception {
             assertThat(ex.getMessage(), containsString("is not shared"));
         }
     }
+
+    public void testSnapshotShardBlobDelete() throws Exception {
+        Client client = client();
+        Path repositoryPath = randomRepoPath();
+        final String repositoryName = "test-repo";
+        final String firstSnapshot = "first-snapshot";
+        final String secondSnapshot = "second-snapshot";
+        final String indexName = "test-idx";
+
+        logger.info("-->  creating repository at {}", repositoryPath.toAbsolutePath());
+        int maxShardBlobDeleteBatchSize = randomIntBetween(1, 1000);
+        createRepository(
+            "test-repo",
+            "mock",
+            Settings.builder()
+                .put("location", repositoryPath)
+                .put(BlobStoreRepository.MAX_SNAPSHOT_SHARD_BLOB_DELETE_BATCH_SIZE.getKey(), maxShardBlobDeleteBatchSize)
+        );
+
+        logger.info("--> creating index-0 and ingest data");
+        createIndex(indexName);
+        ensureGreen();
+        for (int j = 0; j < randomIntBetween(1, 1000); j++) {
+            index(indexName, "_doc", Integer.toString(j), "foo", "bar" + j);
+        }
+        refresh();
+
+        logger.info("--> creating first snapshot");
+        createFullSnapshot(repositoryName, firstSnapshot);
+
+        int numberOfFiles = numberOfFiles(repositoryPath);
+
+        logger.info("--> adding some more documents to test index");
+        for (int j = 0; j < randomIntBetween(100, 10000); ++j) {
+            final BulkRequest bulkRequest = new BulkRequest();
+            for (int i = 0; i < randomIntBetween(100, 1000); ++i) {
+                bulkRequest.add(new IndexRequest(indexName).source("foo" + j, "bar" + i));
+            }
+            client().bulk(bulkRequest).get();
+        }
+        refresh();
+
+        logger.info("--> creating second snapshot");
+        createFullSnapshot(repositoryName, secondSnapshot);
+
+        // Delete second snapshot
+        logger.info("--> delete second snapshot");
+        client.admin().cluster().prepareDeleteSnapshot(repositoryName, secondSnapshot).get();
+
+        logger.info("--> make sure that number of files is back to what it was when the first snapshot was made");
+        assertFileCount(repositoryPath, numberOfFiles);
+
+        logger.info("--> done");
+    }
+
+    public void testSnapshotShardBlobDeletionRepositoryThrowingError() throws Exception {
+        Client client = client();
+        Path repositoryPath = randomRepoPath();
+        final String repositoryName = "test-repo";
+        final String firstSnapshot = "first-snapshot";
+        final String secondSnapshot = "second-snapshot";
+        final String indexName = "test-idx";
+
+        logger.info("-->  creating repository at {}", repositoryPath.toAbsolutePath());
+        int maxShardBlobDeleteBatchSize = randomIntBetween(1, 1000);
+        createRepository(
+            "test-repo",
+            "mock",
+            Settings.builder()
+                .put("location", repositoryPath)
+                .put(BlobStoreRepository.MAX_SNAPSHOT_SHARD_BLOB_DELETE_BATCH_SIZE.getKey(), maxShardBlobDeleteBatchSize)
+        );
+
+        logger.info("--> creating index-0 and ingest data");
+        createIndex(indexName);
+        ensureGreen();
+        for (int j = 0; j < randomIntBetween(1, 1000); j++) {
+            index(indexName, "_doc", Integer.toString(j), "foo", "bar" + j);
+        }
+        refresh();
+
+        logger.info("--> creating first snapshot");
+        createFullSnapshot(repositoryName, firstSnapshot);
+
+        logger.info("--> adding some more documents to test index");
+        for (int j = 0; j < randomIntBetween(100, 1000); ++j) {
+            final BulkRequest bulkRequest = new BulkRequest();
+            for (int i = 0; i < randomIntBetween(100, 1000); ++i) {
+                bulkRequest.add(new IndexRequest(indexName).source("foo" + j, "bar" + i));
+            }
+            client().bulk(bulkRequest).get();
+        }
+        refresh();
+
+        logger.info("--> creating second snapshot");
+        createFullSnapshot(repositoryName, secondSnapshot);
+
+        // Make repository to throw exception when trying to delete stale snapshot shard blobs
+        String clusterManagerNode = internalCluster().getMasterName();
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerNode).repository("test-repo"))
+            .setThrowExceptionWhileDelete(true);
+
+        // Delete second snapshot
+        logger.info("--> delete second snapshot");
+        client.admin().cluster().prepareDeleteSnapshot(repositoryName, secondSnapshot).get();
+
+        // Make repository to work normally
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerNode).repository("test-repo"))
+            .setThrowExceptionWhileDelete(false);
+
+        // This snapshot should delete last snapshot's residual stale shard blobs as well
+        logger.info("--> delete first snapshot");
+        client.admin().cluster().prepareDeleteSnapshot(repositoryName, firstSnapshot).get();
+
+        // Expect two files to remain in the repository:
+        // (1) index-(N+1)
+        // (2) index-latest
+        assertFileCount(repositoryPath, 2);
+
+        logger.info("--> done");
+    }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoryFilterUserMetadataIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoryFilterUserMetadataIT.java
index 9ee479cdd7fe0..0eb37703eb0f1 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoryFilterUserMetadataIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/RepositoryFilterUserMetadataIT.java
@@ -32,14 +32,13 @@
 package org.opensearch.snapshots;
 
 import org.apache.lucene.index.IndexCommit;
-
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
@@ -70,7 +69,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     public void testFilteredRepoMetadataIsUsed() {
-        final String masterName = internalCluster().getMasterName();
+        final String clusterManagerName = internalCluster().getClusterManagerName();
         final String repoName = "test-repo";
         assertAcked(
             client().admin()
@@ -78,7 +77,9 @@ public void testFilteredRepoMetadataIsUsed() {
                 .preparePutRepository(repoName)
                 .setType(MetadataFilteringPlugin.TYPE)
                 .setSettings(
-                    Settings.builder().put("location", randomRepoPath()).put(MetadataFilteringPlugin.MASTER_SETTING_VALUE, masterName)
+                    Settings.builder()
+                        .put("location", randomRepoPath())
+                        .put(MetadataFilteringPlugin.CLUSTER_MANAGER_SETTING_VALUE, clusterManagerName)
                 )
         );
         createIndex("test-idx");
@@ -88,15 +89,18 @@ public void testFilteredRepoMetadataIsUsed() {
             .setWaitForCompletion(true)
             .get()
             .getSnapshotInfo();
-        assertThat(snapshotInfo.userMetadata(), is(Collections.singletonMap(MetadataFilteringPlugin.MOCK_FILTERED_META, masterName)));
+        assertThat(
+            snapshotInfo.userMetadata(),
+            is(Collections.singletonMap(MetadataFilteringPlugin.MOCK_FILTERED_META, clusterManagerName))
+        );
     }
 
-    // Mock plugin that stores the name of the master node that started a snapshot in each snapshot's metadata
+    // Mock plugin that stores the name of the cluster-manager node that started a snapshot in each snapshot's metadata
     public static final class MetadataFilteringPlugin extends org.opensearch.plugins.Plugin implements RepositoryPlugin {
 
         private static final String MOCK_FILTERED_META = "mock_filtered_meta";
 
-        private static final String MASTER_SETTING_VALUE = "initial_master";
+        private static final String CLUSTER_MANAGER_SETTING_VALUE = "initial_cluster_manager";
 
         private static final String TYPE = "mock_meta_filtering";
 
@@ -112,8 +116,8 @@ public Map<String, Repository.Factory> getRepositories(
                 metadata -> new FsRepository(metadata, env, namedXContentRegistry, clusterService, recoverySettings) {
 
                     // Storing the initially expected metadata value here to verify that #filterUserMetadata is only called once on the
-                    // initial master node starting the snapshot
-                    private final String initialMetaValue = metadata.settings().get(MASTER_SETTING_VALUE);
+                    // initial cluster-manager node starting the snapshot
+                    private final String initialMetaValue = metadata.settings().get(CLUSTER_MANAGER_SETTING_VALUE);
 
                     @Override
                     public void finalizeSnapshot(
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/RestoreSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/RestoreSnapshotIT.java
index 3a7fdd4093657..7117818451e14 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/RestoreSnapshotIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/RestoreSnapshotIT.java
@@ -32,23 +32,24 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
+import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequestBuilder;
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.indices.InvalidIndexNameException;
 import org.opensearch.repositories.RepositoriesService;
-import org.opensearch.rest.RestStatus;
 
 import java.nio.file.Path;
 import java.util.Collections;
@@ -80,7 +81,6 @@
 import static org.hamcrest.Matchers.nullValue;
 
 public class RestoreSnapshotIT extends AbstractSnapshotIntegTestCase {
-
     public void testParallelRestoreOperations() {
         String indexName1 = "testindex1";
         String indexName2 = "testindex2";
@@ -973,4 +973,86 @@ public void testForbidDisableSoftDeletesDuringRestore() throws Exception {
         );
         assertThat(restoreError.getMessage(), containsString("cannot disable setting [index.soft_deletes.enabled] on restore"));
     }
+
+    public void testRestoreBalancedReplica() {
+        try {
+            createRepository("test-repo", "fs");
+            DeleteIndexTemplateRequestBuilder deleteTemplate = client().admin().indices().prepareDeleteTemplate("random_index_template");
+            assertAcked(deleteTemplate.execute().actionGet());
+
+            createIndex("test-index", Settings.builder().put("index.number_of_replicas", 0).build());
+            createIndex(".system-index", Settings.builder().put("index.number_of_replicas", 0).build());
+            ensureGreen();
+            clusterAdmin().prepareCreateSnapshot("test-repo", "snapshot-0")
+                .setIndices("test-index", ".system-index")
+                .setWaitForCompletion(true)
+                .get();
+            manageReplicaSettingForDefaultReplica(true);
+
+            final IllegalArgumentException restoreError = expectThrows(
+                IllegalArgumentException.class,
+                () -> clusterAdmin().prepareRestoreSnapshot("test-repo", "snapshot-0")
+                    .setRenamePattern("test-index")
+                    .setRenameReplacement("new-index")
+                    .setIndices("test-index")
+                    .get()
+            );
+            assertThat(
+                restoreError.getMessage(),
+                containsString("expected total copies needs to be a multiple of total awareness attributes [3]")
+            );
+
+            final IllegalArgumentException restoreError2 = expectThrows(
+                IllegalArgumentException.class,
+                () -> clusterAdmin().prepareRestoreSnapshot("test-repo", "snapshot-0")
+                    .setRenamePattern("test-index")
+                    .setRenameReplacement("new-index-2")
+                    .setIndexSettings(
+                        Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 1).put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-1").build()
+                    )
+                    .setIndices("test-index")
+                    .get()
+            );
+            assertThat(
+                restoreError2.getMessage(),
+                containsString("expected max cap on auto expand to be a multiple of total awareness attributes [3]")
+            );
+
+            RestoreSnapshotResponse restoreSnapshotResponse = clusterAdmin().prepareRestoreSnapshot("test-repo", "snapshot-0")
+                .setRenamePattern(".system-index")
+                .setRenameReplacement(".system-index-restore-1")
+                .setWaitForCompletion(true)
+                .setIndices(".system-index")
+                .execute()
+                .actionGet();
+
+            assertThat(restoreSnapshotResponse.getRestoreInfo().totalShards(), greaterThan(0));
+
+            restoreSnapshotResponse = clusterAdmin().prepareRestoreSnapshot("test-repo", "snapshot-0")
+                .setRenamePattern("test-index")
+                .setRenameReplacement("new-index")
+                .setIndexSettings(Settings.builder().put("index.number_of_replicas", 2).build())
+                .setWaitForCompletion(true)
+                .setIndices("test-index")
+                .execute()
+                .actionGet();
+
+            restoreSnapshotResponse = clusterAdmin().prepareRestoreSnapshot("test-repo", "snapshot-0")
+                .setRenamePattern("test-index")
+                .setRenameReplacement("new-index-3")
+                .setIndexSettings(
+                    Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 0).put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-2").build()
+                )
+                .setWaitForCompletion(true)
+                .setIndices("test-index")
+                .execute()
+                .actionGet();
+
+            assertThat(restoreSnapshotResponse.getRestoreInfo().totalShards(), greaterThan(0));
+        } finally {
+            manageReplicaSettingForDefaultReplica(false);
+            randomIndexTemplate();
+        }
+    }
+
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java
new file mode 100644
index 0000000000000..4478a3432e519
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java
@@ -0,0 +1,751 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.opensearch.snapshots;
+
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
+import org.opensearch.action.admin.cluster.node.stats.NodeStats;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsGroup;
+import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
+import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
+import org.opensearch.action.admin.indices.settings.get.GetSettingsRequest;
+import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
+import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequestBuilder;
+import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.GroupShardsIterator;
+import org.opensearch.cluster.routing.ShardIterator;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.store.remote.file.CleanerDaemonThreadLeakFilter;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
+import org.opensearch.monitor.fs.FsInfo;
+import org.opensearch.node.Node;
+import org.opensearch.repositories.fs.FsRepository;
+import org.hamcrest.MatcherAssert;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.FS;
+import static org.opensearch.core.common.util.CollectionUtils.iterableAsArrayList;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+
+@ThreadLeakFilters(filters = CleanerDaemonThreadLeakFilter.class)
+public final class SearchableSnapshotIT extends AbstractSnapshotIntegTestCase {
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    @Override
+    protected Settings.Builder randomRepositorySettings() {
+        final Settings.Builder settings = Settings.builder();
+        settings.put("location", randomRepoPath()).put("compress", randomBoolean());
+        settings.put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path");
+        return settings;
+    }
+
+    private Settings.Builder chunkedRepositorySettings() {
+        final Settings.Builder settings = Settings.builder();
+        settings.put("location", randomRepoPath()).put("compress", randomBoolean());
+        settings.put("chunk_size", 2 << 23, ByteSizeUnit.BYTES);
+        return settings;
+    }
+
+    /**
+     * Tests a happy path scenario for searchable snapshots by creating 2 indices,
+     * taking a snapshot, restoring them as searchable snapshots.
+     * Ensures availability of sufficient data nodes and search capable nodes.
+     */
+    public void testCreateSearchableSnapshot() throws Exception {
+        final String snapshotName = "test-snap";
+        final String repoName = "test-repo";
+        final String indexName1 = "test-idx-1";
+        final String restoredIndexName1 = indexName1 + "-copy";
+        final String indexName2 = "test-idx-2";
+        final String restoredIndexName2 = indexName2 + "-copy";
+        final int numReplicasIndex1 = randomIntBetween(1, 4);
+        final int numReplicasIndex2 = randomIntBetween(0, 2);
+        final Client client = client();
+
+        internalCluster().ensureAtLeastNumDataNodes(Math.max(numReplicasIndex1, numReplicasIndex2) + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex1, 100, indexName1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex2, 100, indexName2);
+
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName1, indexName2);
+        deleteIndicesAndEnsureGreen(client, indexName1, indexName2);
+
+        internalCluster().ensureAtLeastNumSearchNodes(Math.max(numReplicasIndex1, numReplicasIndex2) + 1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName1, restoredIndexName2);
+
+        assertDocCount(restoredIndexName1, 100L);
+        assertDocCount(restoredIndexName2, 100L);
+        assertIndexDirectoryDoesNotExist(restoredIndexName1, restoredIndexName2);
+    }
+
+    public void testSnapshottingSearchableSnapshots() throws Exception {
+        final String repoName = "test-repo";
+        final String indexName = "test-idx";
+        final Client client = client();
+
+        // create an index, add data, snapshot it, then delete it
+        internalCluster().ensureAtLeastNumDataNodes(1);
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, "initial-snapshot", repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        // restore the index as a searchable snapshot
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(repoName, "initial-snapshot")
+            .setRenamePattern("(.+)")
+            .setRenameReplacement("$1-copy-0")
+            .setStorageType(RestoreSnapshotRequest.StorageType.REMOTE_SNAPSHOT)
+            .setWaitForCompletion(true)
+            .execute()
+            .actionGet();
+        ensureGreen();
+        assertDocCount(indexName + "-copy-0", 100L);
+        assertIndexDirectoryDoesNotExist(indexName + "-copy-0");
+
+        // Test that the searchable snapshot index can continue to be snapshotted and restored
+        for (int i = 0; i < 4; i++) {
+            final String repeatedSnapshotName = "test-repeated-snap-" + i;
+            takeSnapshot(client, repeatedSnapshotName, repoName);
+            deleteIndicesAndEnsureGreen(client, "_all");
+            client.admin()
+                .cluster()
+                .prepareRestoreSnapshot(repoName, repeatedSnapshotName)
+                .setRenamePattern("([a-z-]+).*")
+                .setRenameReplacement("$1" + (i + 1))
+                .setWaitForCompletion(true)
+                .execute()
+                .actionGet();
+            ensureGreen();
+            final String restoredIndexName = indexName + "-copy-" + (i + 1);
+            assertDocCount(restoredIndexName, 100L);
+            assertIndexDirectoryDoesNotExist(restoredIndexName);
+        }
+        // Assert all the snapshots exist. Note that AbstractSnapshotIntegTestCase::assertRepoConsistency
+        // will run after this test (and all others) and assert on the consistency of the data in the repo.
+        final GetSnapshotsResponse response = client.admin().cluster().prepareGetSnapshots(repoName).execute().actionGet();
+        final Map<String, List<String>> snapshotInfoMap = response.getSnapshots()
+            .stream()
+            .collect(Collectors.toMap(s -> s.snapshotId().getName(), SnapshotInfo::indices));
+        assertEquals(
+            Map.of(
+                "initial-snapshot",
+                List.of("test-idx"),
+                "test-repeated-snap-0",
+                List.of("test-idx-copy-0"),
+                "test-repeated-snap-1",
+                List.of("test-idx-copy-1"),
+                "test-repeated-snap-2",
+                List.of("test-idx-copy-2"),
+                "test-repeated-snap-3",
+                List.of("test-idx-copy-3")
+            ),
+            snapshotInfoMap
+        );
+    }
+
+    /**
+     * Tests a chunked repository scenario for searchable snapshots by creating an index,
+     * taking a snapshot, restoring it as a searchable snapshot index.
+     */
+    public void testCreateSearchableSnapshotWithChunks() throws Exception {
+        final int numReplicasIndex = randomIntBetween(1, 4);
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        Settings.Builder repositorySettings = chunkedRepositorySettings();
+
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(numReplicasIndex + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex, 1000, indexName);
+        createRepositoryWithSettings(repositorySettings, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+
+        deleteIndicesAndEnsureGreen(client, indexName);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        assertDocCount(restoredIndexName, 1000L);
+    }
+
+    /**
+     * Tests the functionality of remote shard allocation to
+     * ensure it can assign remote shards to a node with local shards given it has the
+     * search role capabilities.
+     */
+    public void testSearchableSnapshotAllocationForLocalAndRemoteShardsOnSameNode() throws Exception {
+        final int numReplicasIndex = randomIntBetween(1, 4);
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(numReplicasIndex + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        assertDocCount(restoredIndexName, 100L);
+        assertDocCount(indexName, 100L);
+    }
+
+    /**
+     * Tests the functionality of remote shard allocation to
+     * ensure it can handle node drops for failover scenarios and the cluster gets back to a healthy state when
+     * nodes with search capabilities are added back to the cluster.
+     */
+    public void testSearchableSnapshotAllocationForFailoverAndRecovery() throws Exception {
+        final int numReplicasIndex = 1;
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        internalCluster().ensureAtLeastNumDataNodes(numReplicasIndex + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex, 100, indexName);
+
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        internalCluster().ensureAtLeastNumSearchNodes(numReplicasIndex + 1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+        assertDocCount(restoredIndexName, 100L);
+
+        logger.info("--> stop a random search node");
+        internalCluster().stopRandomSearchNode();
+        ensureYellow(restoredIndexName);
+        assertDocCount(restoredIndexName, 100L);
+
+        logger.info("--> stop the last search node");
+        internalCluster().stopRandomSearchNode();
+        ensureRed(restoredIndexName);
+
+        logger.info("--> add 3 new search nodes");
+        internalCluster().ensureAtLeastNumSearchNodes(numReplicasIndex + 2);
+        ensureGreen(restoredIndexName);
+        assertDocCount(restoredIndexName, 100);
+
+        logger.info("--> stop a random search node");
+        internalCluster().stopRandomSearchNode();
+        ensureGreen(restoredIndexName);
+        assertDocCount(restoredIndexName, 100);
+    }
+
+    /**
+     * Tests the functionality of index write block on a searchable snapshot index.
+     */
+    public void testSearchableSnapshotIndexIsReadOnly() throws Exception {
+        final String indexName = "test-index";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        assertIndexingBlocked(restoredIndexName);
+        assertTrue(client.admin().indices().prepareDelete(restoredIndexName).get().isAcknowledged());
+        assertThrows(
+            "Expect index to not exist",
+            IndexNotFoundException.class,
+            () -> client.admin().indices().prepareGetIndex().setIndices(restoredIndexName).execute().actionGet()
+        );
+    }
+
+    public void testDeleteSearchableSnapshotBackingIndexThrowsException() throws Exception {
+        final String indexName = "test-index";
+        final Client client = client();
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        createRepositoryWithSettings(null, repoName);
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertThrows(
+            SnapshotInUseDeletionException.class,
+            () -> client().admin().cluster().deleteSnapshot(new DeleteSnapshotRequest(repoName, snapshotName)).actionGet()
+        );
+    }
+
+    public void testDeleteSearchableSnapshotBackingIndex() throws Exception {
+        final String indexName1 = "test-index1";
+        final String indexName2 = "test-index2";
+        final Client client = client();
+        final String repoName = "test-repo";
+        final String snapshotName1 = "test-snapshot1";
+        final String snapshotName2 = "test-snap";
+        createRepositoryWithSettings(null, repoName);
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName1);
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName2);
+        takeSnapshot(client, snapshotName1, repoName, indexName1);
+        takeSnapshot(client, snapshotName2, repoName, indexName2);
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName2, repoName);
+        client().admin().cluster().deleteSnapshot(new DeleteSnapshotRequest(repoName, snapshotName1)).actionGet();
+    }
+
+    private void createIndexWithDocsAndEnsureGreen(int numReplicasIndex, int numOfDocs, String indexName) throws InterruptedException {
+        createIndex(
+            indexName,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, Integer.toString(numReplicasIndex))
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey())
+                .build()
+        );
+        ensureGreen();
+
+        indexRandomDocs(indexName, numOfDocs);
+        ensureGreen();
+    }
+
+    private void takeSnapshot(Client client, String snapshotName, String repoName, String... indices) {
+        logger.info("--> Take a snapshot");
+        final CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(repoName, snapshotName)
+            .setWaitForCompletion(true)
+            .setIndices(indices)
+            .get();
+
+        MatcherAssert.assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        MatcherAssert.assertThat(
+            createSnapshotResponse.getSnapshotInfo().successfulShards(),
+            equalTo(createSnapshotResponse.getSnapshotInfo().totalShards())
+        );
+    }
+
+    private void createRepositoryWithSettings(Settings.Builder repositorySettings, String repoName) {
+        logger.info("--> Create a repository");
+        if (repositorySettings == null) {
+            createRepository(repoName, FsRepository.TYPE);
+        } else {
+            createRepository(repoName, FsRepository.TYPE, repositorySettings);
+        }
+    }
+
+    private void deleteIndicesAndEnsureGreen(Client client, String... indices) {
+        assertTrue(client.admin().indices().prepareDelete(indices).get().isAcknowledged());
+        ensureGreen();
+    }
+
+    private void restoreSnapshotAndEnsureGreen(Client client, String snapshotName, String repoName) {
+        logger.info("--> restore indices as 'remote_snapshot'");
+        client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(repoName, snapshotName)
+            .setRenamePattern("(.+)")
+            .setRenameReplacement("$1-copy")
+            .setStorageType(RestoreSnapshotRequest.StorageType.REMOTE_SNAPSHOT)
+            .setWaitForCompletion(true)
+            .execute()
+            .actionGet();
+        ensureGreen();
+    }
+
+    private void assertRemoteSnapshotIndexSettings(Client client, String... snapshotIndexNames) {
+        GetSettingsResponse settingsResponse = client.admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(snapshotIndexNames))
+            .actionGet();
+        assertEquals(snapshotIndexNames.length, settingsResponse.getIndexToSettings().keySet().size());
+        for (String snapshotIndexName : snapshotIndexNames) {
+            assertEquals(
+                IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey(),
+                settingsResponse.getSetting(snapshotIndexName, IndexModule.INDEX_STORE_TYPE_SETTING.getKey())
+            );
+        }
+    }
+
+    private void assertIndexingBlocked(String index) {
+        try {
+            final IndexRequestBuilder builder = client().prepareIndex(index);
+            builder.setSource("foo", "bar");
+            builder.execute().actionGet();
+            fail("Expected operation to throw an exception");
+        } catch (ClusterBlockException e) {
+            MatcherAssert.assertThat(e.blocks(), contains(IndexMetadata.REMOTE_READ_ONLY_ALLOW_DELETE));
+        }
+    }
+
+    public void testUpdateIndexSettings() throws InterruptedException {
+        final String indexName = "test-index";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        testUpdateIndexSettingsOnlyNotAllowedSettings(restoredIndexName);
+        testUpdateIndexSettingsOnlyAllowedSettings(restoredIndexName);
+        testUpdateIndexSettingsAtLeastOneNotAllowedSettings(restoredIndexName);
+    }
+
+    private void testUpdateIndexSettingsOnlyNotAllowedSettings(String index) {
+        try {
+            final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
+            builder.setSettings(Map.of("index.refresh_interval", 10));
+            builder.execute().actionGet();
+            fail("Expected operation to throw an exception");
+        } catch (ClusterBlockException e) {
+            MatcherAssert.assertThat(e.blocks(), contains(IndexMetadata.REMOTE_READ_ONLY_ALLOW_DELETE));
+        }
+    }
+
+    private void testUpdateIndexSettingsOnlyAllowedSettings(String index) {
+        final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
+        builder.setSettings(Map.of("index.max_result_window", 1000, "index.search.slowlog.threshold.query.warn", "10s"));
+        AcknowledgedResponse settingsResponse = builder.execute().actionGet();
+        assertThat(settingsResponse, notNullValue());
+    }
+
+    private void testUpdateIndexSettingsAtLeastOneNotAllowedSettings(String index) {
+        try {
+            final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
+            builder.setSettings(
+                Map.of("index.max_result_window", 5000, "index.search.slowlog.threshold.query.warn", "15s", "index.refresh_interval", 10)
+            );
+            builder.execute().actionGet();
+            fail("Expected operation to throw an exception");
+        } catch (ClusterBlockException e) {
+            MatcherAssert.assertThat(e.blocks(), contains(IndexMetadata.REMOTE_READ_ONLY_ALLOW_DELETE));
+        }
+    }
+
+    public void testFileCacheStats() throws Exception {
+        final String snapshotName = "test-snap";
+        final String repoName = "test-repo";
+        final String indexName1 = "test-idx-1";
+        final Client client = client();
+        final int numNodes = 2;
+
+        internalCluster().ensureAtLeastNumDataNodes(numNodes);
+        createIndexWithDocsAndEnsureGreen(1, 100, indexName1);
+
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName1);
+        deleteIndicesAndEnsureGreen(client, indexName1);
+        assertAllNodesFileCacheEmpty();
+
+        internalCluster().ensureAtLeastNumSearchNodes(numNodes);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertNodesFileCacheNonEmpty(numNodes);
+    }
+
+    /**
+     * Tests file cache restore scenario for searchable snapshots by creating an index,
+     * taking a snapshot, restoring it as a searchable snapshot.
+     * It ensures file cache is restored post node restart.
+     */
+    public void testFileCacheRestore() throws Exception {
+        final String snapshotName = "test-snap";
+        final String repoName = "test-repo";
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        // Keeping the replicas to 0 for reproducible cache results as shards can get reassigned otherwise
+        final int numReplicasIndex = 0;
+        final Client client = client();
+
+        internalCluster().ensureAtLeastNumDataNodes(numReplicasIndex + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicasIndex, 100, indexName);
+
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        internalCluster().ensureAtLeastNumSearchNodes(numReplicasIndex + 1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        assertDocCount(restoredIndexName, 100L);
+        assertIndexDirectoryDoesNotExist(restoredIndexName);
+
+        NodesStatsResponse preRestoreStats = client().admin().cluster().nodesStats(new NodesStatsRequest().all()).actionGet();
+        for (NodeStats nodeStats : preRestoreStats.getNodes()) {
+            if (nodeStats.getNode().isSearchNode()) {
+                internalCluster().restartNode(nodeStats.getNode().getName());
+            }
+        }
+
+        NodesStatsResponse postRestoreStats = client().admin().cluster().nodesStats(new NodesStatsRequest().all()).actionGet();
+        Map<String, NodeStats> preRestoreStatsMap = preRestoreStats.getNodesMap();
+        Map<String, NodeStats> postRestoreStatsMap = postRestoreStats.getNodesMap();
+        for (String node : postRestoreStatsMap.keySet()) {
+            NodeStats preRestoreStat = preRestoreStatsMap.get(node);
+            NodeStats postRestoreStat = postRestoreStatsMap.get(node);
+            if (preRestoreStat.getNode().isSearchNode()) {
+                assertEquals(preRestoreStat.getFileCacheStats().getUsed(), postRestoreStat.getFileCacheStats().getUsed());
+            }
+        }
+    }
+
+    /**
+     * Picks a shard out of the cluster state for each given index and asserts
+     * that the 'index' directory does not exist in the node's file system.
+     * This assertion is digging a bit into the implementation details to
+     * verify that the Lucene segment files are not copied from the snapshot
+     * repository to the node's local disk for a remote snapshot index.
+     */
+    private void assertIndexDirectoryDoesNotExist(String... indexNames) {
+        final ClusterState state = client().admin().cluster().prepareState().get().getState();
+        for (String indexName : indexNames) {
+            final Index index = state.metadata().index(indexName).getIndex();
+            // Get the primary shards for the given index
+            final GroupShardsIterator<ShardIterator> shardIterators = state.getRoutingTable()
+                .activePrimaryShardsGrouped(new String[] { indexName }, false);
+            // Randomly pick one of the shards
+            final List<ShardIterator> iterators = iterableAsArrayList(shardIterators);
+            final ShardIterator shardIterator = RandomPicks.randomFrom(random(), iterators);
+            final ShardRouting shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertTrue(shardRouting.primary());
+            assertTrue(shardRouting.assignedToNode());
+            // Get the file system stats for the assigned node
+            final String nodeId = shardRouting.currentNodeId();
+            final NodesStatsResponse nodeStats = client().admin().cluster().prepareNodesStats(nodeId).addMetric(FS.metricName()).get();
+            for (FsInfo.Path info : nodeStats.getNodes().get(0).getFs()) {
+                // Build the expected path for the index data for a "normal"
+                // index and assert it does not exist
+                final String path = info.getPath();
+                final Path file = PathUtils.get(path)
+                    .resolve("indices")
+                    .resolve(index.getUUID())
+                    .resolve(Integer.toString(shardRouting.getId()))
+                    .resolve("index");
+                MatcherAssert.assertThat("Expect file not to exist: " + file, Files.exists(file), is(false));
+            }
+        }
+    }
+
+    private void assertAllNodesFileCacheEmpty() {
+        NodesStatsResponse response = client().admin().cluster().nodesStats(new NodesStatsRequest().all()).actionGet();
+        for (NodeStats stats : response.getNodes()) {
+            FileCacheStats fcstats = stats.getFileCacheStats();
+            if (fcstats != null) {
+                assertTrue(isFileCacheEmpty(fcstats));
+            }
+        }
+    }
+
+    private void assertNodesFileCacheNonEmpty(int numNodes) {
+        NodesStatsResponse response = client().admin().cluster().nodesStats(new NodesStatsRequest().all()).actionGet();
+        int nonEmptyFileCacheNodes = 0;
+        for (NodeStats stats : response.getNodes()) {
+            FileCacheStats fcStats = stats.getFileCacheStats();
+            if (stats.getNode().isSearchNode()) {
+                if (!isFileCacheEmpty(fcStats)) {
+                    nonEmptyFileCacheNodes++;
+                }
+            } else {
+                assertNull(fcStats);
+            }
+
+        }
+        assertEquals(numNodes, nonEmptyFileCacheNodes);
+    }
+
+    private boolean isFileCacheEmpty(FileCacheStats stats) {
+        return stats.getUsed().getBytes() == 0L && stats.getActive().getBytes() == 0L;
+    }
+
+    public void testPruneFileCacheOnIndexDeletion() throws Exception {
+        final String snapshotName = "test-snap";
+        final String repoName = "test-repo";
+        final String indexName1 = "test-idx-1";
+        final String restoredIndexName1 = indexName1 + "-copy";
+        final Client client = client();
+        final int numNodes = 2;
+
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(numNodes);
+        createIndexWithDocsAndEnsureGreen(1, 100, indexName1);
+
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName1);
+        deleteIndicesAndEnsureGreen(client, indexName1);
+
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName1);
+        assertNodesFileCacheNonEmpty(numNodes);
+
+        deleteIndicesAndEnsureGreen(client, restoredIndexName1);
+        assertAllNodesFileCacheEmpty();
+    }
+
+    /**
+     * Test scenario that checks the cache folder location on search nodes for the restored index on snapshot restoration
+     * and ensures the index folder is cleared on all nodes post index deletion
+     */
+    public void testCacheIndexFilesClearedOnDelete() throws Exception {
+        final int numReplicas = randomIntBetween(1, 4);
+        final int numShards = numReplicas + 1;
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(numShards);
+        createIndexWithDocsAndEnsureGreen(numReplicas, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertDocCount(restoredIndexName, 100L);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        // The index count will be 1 since there is only a single restored index "test-idx-copy"
+        assertCacheDirectoryReplicaAndIndexCount(numShards, 1);
+
+        // The local cache files should be closed by deleting the restored index
+        deleteIndicesAndEnsureGreen(client, restoredIndexName);
+
+        logger.info("--> validate cache file path is deleted");
+        // The index count will be 0 since the only restored index "test-idx-copy" was deleted
+        assertCacheDirectoryReplicaAndIndexCount(numShards, 0);
+        logger.info("--> validated that the cache file path doesn't exist");
+    }
+
+    /**
+     * Test scenario that validates that the default search preference for searchable snapshot
+     * is primary shards
+     */
+    public void testDefaultShardPreference() throws Exception {
+        final int numReplicas = 1;
+        final String indexName = "test-idx";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        // Create an index, snapshot and restore as a searchable snapshot index
+        internalCluster().ensureAtLeastNumSearchAndDataNodes(numReplicas + 1);
+        createIndexWithDocsAndEnsureGreen(numReplicas, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+        assertDocCount(restoredIndexName, 100L);
+        assertRemoteSnapshotIndexSettings(client, restoredIndexName);
+
+        // ClusterSearchShards API returns a list of shards that will be used
+        // when querying a particular index
+        ClusterSearchShardsGroup[] shardGroups = client.admin()
+            .cluster()
+            .searchShards(new ClusterSearchShardsRequest(restoredIndexName))
+            .actionGet()
+            .getGroups();
+
+        // Ensure when no preferences are set (default preference), the only compatible shards are primary
+        for (ClusterSearchShardsGroup shardsGroup : shardGroups) {
+            assertEquals(1, shardsGroup.getShards().length);
+            assertTrue(shardsGroup.getShards()[0].primary());
+        }
+
+        // Ensure when preferences are set, all the compatible shards are returned
+        shardGroups = client.admin()
+            .cluster()
+            .searchShards(new ClusterSearchShardsRequest(restoredIndexName).preference("foo"))
+            .actionGet()
+            .getGroups();
+
+        // Ensures that the compatible shards are not just primaries
+        for (ClusterSearchShardsGroup shardsGroup : shardGroups) {
+            assertTrue(shardsGroup.getShards().length > 1);
+            boolean containsReplica = Arrays.stream(shardsGroup.getShards())
+                .map(shardRouting -> !shardRouting.primary())
+                .reduce(false, (s1, s2) -> s1 || s2);
+            assertTrue(containsReplica);
+        }
+    }
+
+    /**
+     * Asserts the cache folder count to match the number of shards and the number of indices within the cache folder
+     * as provided.
+     * @param numCacheFolderCount total number of cache folders that should exist for the test case
+     * @param numIndexCount total number of index folder locations that should exist within the cache folder
+     */
+    private void assertCacheDirectoryReplicaAndIndexCount(int numCacheFolderCount, int numIndexCount) throws IOException {
+        // Get the available NodeEnvironment instances
+        Iterable<Node> nodes = internalCluster().getInstances(Node.class);
+
+        // Filter out search NodeEnvironment(s) since FileCache is initialized only on search nodes and
+        // collect the path for all the cache locations on search nodes.
+        List<Path> searchNodeFileCachePaths = StreamSupport.stream(nodes.spliterator(), false)
+            .filter(node -> node.fileCache() != null)
+            .map(node -> node.getNodeEnvironment().fileCacheNodePath().fileCachePath)
+            .collect(Collectors.toList());
+
+        // Walk through the cache directory on nodes
+        for (Path fileCachePath : searchNodeFileCachePaths) {
+            assertTrue(Files.exists(fileCachePath));
+            assertTrue(Files.isDirectory(fileCachePath));
+            try (Stream<Path> dataPathStream = Files.list(fileCachePath)) {
+                assertEquals(numIndexCount, dataPathStream.count());
+            }
+        }
+        // Verifies if all the shards (primary and replica) have been deleted
+        assertEquals(numCacheFolderCount, searchNodeFileCachePaths.size());
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java
new file mode 100644
index 0000000000000..c2ce7e48f92d2
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java
@@ -0,0 +1,309 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.snapshots;
+
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequestBuilder;
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.action.admin.indices.settings.get.GetSettingsRequest;
+import org.opensearch.action.admin.indices.settings.get.GetSettingsResponse;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.indices.IndicesService.CLUSTER_SETTING_REPLICATION_TYPE;
+import static org.opensearch.indices.replication.SegmentReplicationBaseIT.waitForSearchableDocs;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SegmentReplicationSnapshotIT extends AbstractSnapshotIntegTestCase {
+    private static final String INDEX_NAME = "test-segrep-idx";
+    private static final String RESTORED_INDEX_NAME = INDEX_NAME + "-restored";
+    private static final int SHARD_COUNT = 1;
+    private static final int REPLICA_COUNT = 1;
+    private static final int DOC_COUNT = 1010;
+
+    private static final String REPOSITORY_NAME = "test-segrep-repo";
+    private static final String SNAPSHOT_NAME = "test-segrep-snapshot";
+
+    public Settings segRepEnableIndexSettings() {
+        return getShardSettings().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+    }
+
+    public Settings docRepEnableIndexSettings() {
+        return getShardSettings().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+    }
+
+    public Settings.Builder getShardSettings() {
+        return Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, SHARD_COUNT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT);
+    }
+
+    public Settings restoreIndexSegRepSettings() {
+        return Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+    }
+
+    public Settings restoreIndexDocRepSettings() {
+        return Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+    }
+
+    @Override
+    protected boolean addMockInternalEngine() {
+        return false;
+    }
+
+    public void ingestData(int docCount, String indexName) throws Exception {
+        for (int i = 0; i < docCount; i++) {
+            client().prepareIndex(indexName).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+    }
+
+    // Start cluster with provided settings and return the node names as list
+    public List<String> startClusterWithSettings(Settings indexSettings, int replicaCount) throws Exception {
+        // Start primary
+        final String primaryNode = internalCluster().startNode();
+        List<String> nodeNames = new ArrayList<>();
+        nodeNames.add(primaryNode);
+        for (int i = 0; i < replicaCount; i++) {
+            nodeNames.add(internalCluster().startNode());
+        }
+        createIndex(INDEX_NAME, indexSettings);
+        ensureGreen(INDEX_NAME);
+        // Ingest data
+        ingestData(DOC_COUNT, INDEX_NAME);
+        return nodeNames;
+    }
+
+    public void createSnapshot() {
+        // Snapshot declaration
+        Path absolutePath = randomRepoPath().toAbsolutePath();
+        // Create snapshot
+        createRepository(REPOSITORY_NAME, "fs", absolutePath);
+        CreateSnapshotResponse createSnapshotResponse = client().admin()
+            .cluster()
+            .prepareCreateSnapshot(REPOSITORY_NAME, SNAPSHOT_NAME)
+            .setWaitForCompletion(true)
+            .setIndices(INDEX_NAME)
+            .get();
+        assertEquals(createSnapshotResponse.getSnapshotInfo().successfulShards(), createSnapshotResponse.getSnapshotInfo().totalShards());
+        assertEquals(createSnapshotResponse.getSnapshotInfo().state(), SnapshotState.SUCCESS);
+    }
+
+    public RestoreSnapshotResponse restoreSnapshotWithSettings(Settings indexSettings) {
+        RestoreSnapshotRequestBuilder builder = client().admin()
+            .cluster()
+            .prepareRestoreSnapshot(REPOSITORY_NAME, SNAPSHOT_NAME)
+            .setWaitForCompletion(false)
+            .setRenamePattern(INDEX_NAME)
+            .setRenameReplacement(RESTORED_INDEX_NAME);
+        if (indexSettings != null) {
+            builder.setIndexSettings(indexSettings);
+        }
+        return builder.get();
+    }
+
+    public void testRestoreOnSegRep() throws Exception {
+        // Start cluster with one primary and one replica node
+        startClusterWithSettings(segRepEnableIndexSettings(), 1);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+        assertFalse("index [" + INDEX_NAME + "] should have been deleted", indexExists(INDEX_NAME));
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(null);
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "SEGMENT");
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSnapshotOnSegRep_RestoreOnSegRepDuringIngestion() throws Exception {
+        List<String> nodes = startClusterWithSettings(segRepEnableIndexSettings(), 1);
+        waitForSearchableDocs(INDEX_NAME, DOC_COUNT, nodes);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+        assertFalse("index [" + INDEX_NAME + "] should have been deleted", indexExists(INDEX_NAME));
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(null);
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        assertBusy(() -> ensureGreen(RESTORED_INDEX_NAME), 60, TimeUnit.SECONDS);
+        final int docCountPostRestore = 1001;
+        final int totalDocCount = DOC_COUNT + docCountPostRestore;
+        for (int i = DOC_COUNT; i < totalDocCount; i++) {
+            client().prepareIndex(RESTORED_INDEX_NAME).setId(Integer.toString(i)).setSource("field", "value" + i).execute().actionGet();
+        }
+        flushAndRefresh(RESTORED_INDEX_NAME);
+        assertBusy(() -> ensureGreen(RESTORED_INDEX_NAME), 60, TimeUnit.SECONDS);
+        waitForSearchableDocs(RESTORED_INDEX_NAME, totalDocCount, nodes);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "SEGMENT");
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, totalDocCount);
+    }
+
+    public void testSnapshotOnDocRep_RestoreOnSegRep() throws Exception {
+        startClusterWithSettings(docRepEnableIndexSettings(), 1);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(restoreIndexSegRepSettings());
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "SEGMENT");
+
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSnapshotOnSegRep_RestoreOnDocRep() throws Exception {
+        // Start a cluster with one primary and one replica
+        startClusterWithSettings(segRepEnableIndexSettings(), 1);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(restoreIndexDocRepSettings());
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "DOCUMENT");
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSnapshotOnDocRep_RestoreOnDocRep() throws Exception {
+        startClusterWithSettings(docRepEnableIndexSettings(), 1);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(restoreIndexDocRepSettings());
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "DOCUMENT");
+
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testRestoreOnReplicaNode() throws Exception {
+        List<String> nodeNames = startClusterWithSettings(segRepEnableIndexSettings(), 1);
+        final String primaryNode = nodeNames.get(0);
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+        assertFalse("index [" + INDEX_NAME + "] should have been deleted", indexExists(INDEX_NAME));
+
+        // stop the primary node so that restoration happens on replica node
+        internalCluster().stopRandomNode(InternalTestCluster.nameFilter(primaryNode));
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(null);
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        internalCluster().startNode();
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, "index.replication.type"), "SEGMENT");
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSnapshotRestoreOnIndexWithSegRepClusterSetting() throws Exception {
+        Settings settings = Settings.builder()
+            .put(super.featureFlagSettings())
+            .put(CLUSTER_SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+
+        // Starting two nodes with primary and replica shards respectively.
+        final String primaryNode = internalCluster().startNode(settings);
+        prepareCreate(
+            INDEX_NAME,
+            Settings.builder()
+                // we want to override cluster replication setting by passing a index replication setting
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, REPLICA_COUNT)
+        ).get();
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        final String replicaNode = internalCluster().startNode(settings);
+        ensureGreen(INDEX_NAME);
+
+        createSnapshot();
+        // Delete index
+        assertAcked(client().admin().indices().delete(new DeleteIndexRequest(INDEX_NAME)).get());
+        assertFalse("index [" + INDEX_NAME + "] should have been deleted", indexExists(INDEX_NAME));
+
+        RestoreSnapshotResponse restoreSnapshotResponse = restoreSnapshotWithSettings(null);
+
+        // Assertions
+        assertEquals(restoreSnapshotResponse.status(), RestStatus.ACCEPTED);
+        ensureGreen(RESTORED_INDEX_NAME);
+        GetSettingsResponse settingsResponse = client().admin()
+            .indices()
+            .getSettings(new GetSettingsRequest().indices(RESTORED_INDEX_NAME).includeDefaults(true))
+            .get();
+        assertEquals(settingsResponse.getSetting(RESTORED_INDEX_NAME, SETTING_REPLICATION_TYPE), ReplicationType.DOCUMENT.toString());
+
+        // Verify index setting isSegRepEnabled.
+        Index index = resolveIndex(RESTORED_INDEX_NAME);
+        IndicesService indicesService = internalCluster().getInstance(IndicesService.class);
+        assertEquals(indicesService.indexService(index).getIndexSettings().isSegRepEnabled(), false);
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SharedClusterSnapshotRestoreIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SharedClusterSnapshotRestoreIT.java
index 88fcd075a563f..62cbf171e8146 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SharedClusterSnapshotRestoreIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SharedClusterSnapshotRestoreIT.java
@@ -33,11 +33,9 @@
 package org.opensearch.snapshots;
 
 import org.apache.lucene.util.BytesRef;
-
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
@@ -65,17 +63,18 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Numbers;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.BytesRefUtils;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineTestCase;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
@@ -588,7 +587,7 @@ public void testDataFileCorruptionDuringRestore() throws Exception {
         RestoreSnapshotResponse restoreSnapshotResponse = client.admin()
             .cluster()
             .prepareRestoreSnapshot("test-repo", "test-snap")
-            .setMasterNodeTimeout("30s")
+            .setClusterManagerNodeTimeout("30s")
             .setWaitForCompletion(true)
             .execute()
             .actionGet();
@@ -1916,7 +1915,7 @@ public void testSnapshotCanceledOnRemovedShard() throws Exception {
         waitForBlock(blockedNode, repo, TimeValue.timeValueSeconds(10));
 
         logger.info("--> removing primary shard that is being snapshotted");
-        ClusterState clusterState = internalCluster().clusterService(internalCluster().getMasterName()).state();
+        ClusterState clusterState = internalCluster().clusterService(internalCluster().getClusterManagerName()).state();
         IndexRoutingTable indexRoutingTable = clusterState.getRoutingTable().index(index);
         String nodeWithPrimary = clusterState.nodes().get(indexRoutingTable.shard(0).primaryShard().currentNodeId()).getName();
         assertNotNull("should be at least one node with a primary shard", nodeWithPrimary);
@@ -2368,13 +2367,13 @@ public void testIndexLatestFailuresIgnored() throws Exception {
         final String repoName = "test-repo";
         final Path repoPath = randomRepoPath();
         createRepository(repoName, "mock", repoPath);
-        final MockRepository repository = (MockRepository) internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class)
+        final MockRepository repository = (MockRepository) internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class)
             .repository(repoName);
         repository.setFailOnIndexLatest(true);
         createFullSnapshot(repoName, "snapshot-1");
         repository.setFailOnIndexLatest(false);
         createFullSnapshot(repoName, "snapshot-2");
-        final long repoGenInIndexLatest = Numbers.bytesToLong(
+        final long repoGenInIndexLatest = BytesRefUtils.bytesToLong(
             new BytesRef(Files.readAllBytes(repoPath.resolve(BlobStoreRepository.INDEX_LATEST_BLOB)))
         );
         assertEquals(getRepositoryData(repoName).getGenId(), repoGenInIndexLatest);
@@ -2385,14 +2384,14 @@ public void testIndexLatestFailuresIgnored() throws Exception {
             Settings.builder().put("location", repoPath).put(BlobStoreRepository.SUPPORT_URL_REPO.getKey(), false)
         );
         createFullSnapshot(repoName, "snapshot-3");
-        final long repoGenInIndexLatest2 = Numbers.bytesToLong(
+        final long repoGenInIndexLatest2 = BytesRefUtils.bytesToLong(
             new BytesRef(Files.readAllBytes(repoPath.resolve(BlobStoreRepository.INDEX_LATEST_BLOB)))
         );
         assertEquals("index.latest should not have been written to", repoGenInIndexLatest, repoGenInIndexLatest2);
 
         createRepository(repoName, "fs", repoPath);
         createFullSnapshot(repoName, "snapshot-4");
-        final long repoGenInIndexLatest3 = Numbers.bytesToLong(
+        final long repoGenInIndexLatest3 = BytesRefUtils.bytesToLong(
             new BytesRef(Files.readAllBytes(repoPath.resolve(BlobStoreRepository.INDEX_LATEST_BLOB)))
         );
         assertEquals(getRepositoryData(repoName).getGenId(), repoGenInIndexLatest3);
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotCustomPluginStateIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotCustomPluginStateIT.java
index ea1635b1d8053..b2dcab61c05cb 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotCustomPluginStateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotCustomPluginStateIT.java
@@ -40,10 +40,10 @@
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
 import org.opensearch.action.ingest.DeletePipelineRequest;
 import org.opensearch.action.ingest.GetPipelineResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.ingest.IngestTestPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptEngine;
@@ -115,7 +115,7 @@ public void testIncludeGlobalState() throws Exception {
                     .endArray()
                     .endObject()
             );
-            assertAcked(clusterAdmin().preparePutPipeline("barbaz", pipelineSource, XContentType.JSON).get());
+            assertAcked(clusterAdmin().preparePutPipeline("barbaz", pipelineSource, MediaTypeRegistry.JSON).get());
         }
 
         if (testScript) {
@@ -125,7 +125,7 @@ public void testIncludeGlobalState() throws Exception {
                     .setId("foobar")
                     .setContent(
                         new BytesArray("{\"script\": { \"lang\": \"" + MockScriptEngine.NAME + "\", \"source\": \"1\"} }"),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
             );
         }
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotShardsServiceIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotShardsServiceIT.java
index 762656e251659..ef7c61205855e 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotShardsServiceIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotShardsServiceIT.java
@@ -60,7 +60,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     public void testRetryPostingSnapshotStatusMessages() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
 
         createRepository("test-repo", "mock");
@@ -83,7 +83,7 @@ public void testRetryPostingSnapshotStatusMessages() throws Exception {
         final SnapshotId snapshotId = getSnapshot("test-repo", "test-snap").snapshotId();
 
         logger.info("--> start disrupting cluster");
-        final NetworkDisruption networkDisruption = isolateMasterDisruption(NetworkDisruption.NetworkDelay.random(random()));
+        final NetworkDisruption networkDisruption = isolateClusterManagerDisruption(NetworkDisruption.NetworkDelay.random(random()));
         internalCluster().setDisruptionScheme(networkDisruption);
         networkDisruption.startDisrupting();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotStatusApisIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotStatusApisIT.java
index 6c697439b241d..c574233d25051 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotStatusApisIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SnapshotStatusApisIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
@@ -45,11 +44,12 @@
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.SnapshotsInProgress;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -110,6 +110,37 @@ public void testStatusApiConsistency() {
         assertEquals(snStatus.getStats().getTime(), snapshotInfo.endTime() - snapshotInfo.startTime());
     }
 
+    public void testStatusAPICallForShallowCopySnapshot() {
+        disableRepoConsistencyCheck("Remote store repository is being used for the test");
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNode();
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "fs", snapshotRepoSettingsForShallowCopy());
+
+        final String indexName = "index-1";
+        createIndex(indexName);
+        ensureGreen();
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            index(indexName, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+
+        final String snapshot = "snapshot";
+        createFullSnapshot(snapshotRepoName, snapshot);
+
+        final SnapshotStatus snapshotStatus = getSnapshotStatus(snapshotRepoName, snapshot);
+        assertThat(snapshotStatus.getState(), is(SnapshotsInProgress.State.SUCCESS));
+
+        final SnapshotIndexShardStatus snapshotShardState = stateFirstShard(snapshotStatus, indexName);
+        assertThat(snapshotShardState.getStage(), is(SnapshotIndexShardStage.DONE));
+        assertThat(snapshotShardState.getStats().getTotalFileCount(), greaterThan(0));
+        assertThat(snapshotShardState.getStats().getTotalSize(), greaterThan(0L));
+        assertThat(snapshotShardState.getStats().getIncrementalFileCount(), greaterThan(0));
+        assertThat(snapshotShardState.getStats().getIncrementalSize(), greaterThan(0L));
+    }
+
     public void testStatusAPICallInProgressSnapshot() throws Exception {
         createRepository("test-repo", "mock", Settings.builder().put("location", randomRepoPath()).put("block_on_data", true));
 
@@ -237,8 +268,8 @@ public void testCorrectCountsForDoneShards() throws Exception {
         blockDataNode(repoName, dataNodeOne);
 
         final String snapshotOne = "snap-1";
-        // restarting a data node below so using a master client here
-        final ActionFuture<CreateSnapshotResponse> responseSnapshotOne = internalCluster().masterClient()
+        // restarting a data node below so using a cluster-manager client here
+        final ActionFuture<CreateSnapshotResponse> responseSnapshotOne = internalCluster().clusterManagerClient()
             .admin()
             .cluster()
             .prepareCreateSnapshot(repoName, snapshotOne)
@@ -326,6 +357,47 @@ public void testSnapshotStatusOnFailedSnapshot() throws Exception {
         assertEquals(SnapshotsInProgress.State.FAILED, snapshotsStatusResponse.getSnapshots().get(0).getState());
     }
 
+    public void testStatusAPICallInProgressShallowSnapshot() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNode();
+
+        final String snapshotRepoName = "snapshot-repo-name";
+        createRepository(snapshotRepoName, "mock", snapshotRepoSettingsForShallowCopy().put("block_on_data", true));
+
+        final String indexName = "index-1";
+        createIndex(indexName);
+        ensureGreen();
+        logger.info("--> indexing some data");
+        for (int i = 0; i < 100; i++) {
+            index(indexName, "_doc", Integer.toString(i), "foo", "bar" + i);
+        }
+        refresh();
+
+        logger.info("--> snapshot");
+        ActionFuture<CreateSnapshotResponse> createSnapshotResponseActionFuture = startFullSnapshot(snapshotRepoName, "test-snap");
+
+        logger.info("--> wait for data nodes to get blocked");
+        waitForBlockOnAnyDataNode(snapshotRepoName, TimeValue.timeValueMinutes(1));
+        awaitNumberOfSnapshotsInProgress(1);
+        assertEquals(
+            SnapshotsInProgress.State.STARTED,
+            client().admin()
+                .cluster()
+                .prepareSnapshotStatus(snapshotRepoName)
+                .setSnapshots("test-snap")
+                .get()
+                .getSnapshots()
+                .get(0)
+                .getState()
+        );
+
+        logger.info("--> unblock all data nodes");
+        unblockAllDataNodes(snapshotRepoName);
+
+        logger.info("--> wait for snapshot to finish");
+        createSnapshotResponseActionFuture.actionGet();
+    }
+
     public void testGetSnapshotsRequest() throws Exception {
         final String repositoryName = "test-repo";
         final String indexName = "test-idx";
@@ -379,6 +451,17 @@ public void testGetSnapshotsRequest() throws Exception {
             .get();
         assertEquals(1, getSnapshotsResponse.getSnapshots().size());
         assertEquals("snap-on-empty-repo", getSnapshotsResponse.getSnapshots().get(0).snapshotId().getName());
+
+        // there is an in-progress snapshot, make sure we return empty result when getting a non-existing snapshot with setting
+        // ignore_unavailable to true
+        getSnapshotsResponse = client.admin()
+            .cluster()
+            .prepareGetSnapshots("test-repo")
+            .setIgnoreUnavailable(true)
+            .addSnapshots("non-existent-snapshot")
+            .get();
+        assertEquals(0, getSnapshotsResponse.getSnapshots().size());
+
         unblockNode(repositoryName, initialBlockedNode); // unblock node
         admin().cluster().prepareDeleteSnapshot(repositoryName, "snap-on-empty-repo").get();
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SystemRepositoryIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SystemRepositoryIT.java
new file mode 100644
index 0000000000000..f50fc691fb232
--- /dev/null
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SystemRepositoryIT.java
@@ -0,0 +1,71 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.snapshots;
+
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.repositories.RepositoryException;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.Before;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SystemRepositoryIT extends AbstractSnapshotIntegTestCase {
+    protected Path absolutePath;
+    final String systemRepoName = "system-repo-name";
+
+    @Before
+    public void setup() {
+        absolutePath = randomRepoPath().toAbsolutePath();
+    }
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(remoteStoreClusterSettings(systemRepoName, absolutePath))
+            .build();
+    }
+
+    public void testRestrictedSettingsCantBeUpdated() {
+        disableRepoConsistencyCheck("System repository is being used for the test");
+
+        internalCluster().startNode();
+        final Client client = client();
+        final Settings.Builder repoSettings = Settings.builder().put("location", randomRepoPath());
+
+        RepositoryException e = expectThrows(
+            RepositoryException.class,
+            () -> client.admin().cluster().preparePutRepository(systemRepoName).setType("mock").setSettings(repoSettings).get()
+        );
+        assertEquals(
+            e.getMessage(),
+            "[system-repo-name] trying to modify an unmodifiable attribute type of system "
+                + "repository from current value [fs] to new value [mock]"
+        );
+    }
+
+    public void testSystemRepositoryNonRestrictedSettingsCanBeUpdated() {
+        disableRepoConsistencyCheck("System repository is being used for the test");
+
+        internalCluster().startNode();
+        final Client client = client();
+        final Settings.Builder repoSettings = Settings.builder().put("location", absolutePath).put("chunk_size", new ByteSizeValue(20));
+
+        assertAcked(
+            client.admin().cluster().preparePutRepository(systemRepoName).setType(FsRepository.TYPE).setSettings(repoSettings).get()
+        );
+    }
+}
diff --git a/server/src/internalClusterTest/java/org/opensearch/update/UpdateIT.java b/server/src/internalClusterTest/java/org/opensearch/update/UpdateIT.java
index 16b0e8829b1a7..b46d27bafb2a5 100644
--- a/server/src/internalClusterTest/java/org/opensearch/update/UpdateIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/update/UpdateIT.java
@@ -33,7 +33,6 @@
 package org.opensearch.update;
 
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.alias.Alias;
@@ -49,16 +48,17 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.engine.DocumentMissingException;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -669,7 +669,7 @@ public void run() {
 
     public void testStressUpdateDeleteConcurrency() throws Exception {
         // We create an index with merging disabled so that deletes don't get merged away
-        assertAcked(prepareCreate("test").setSettings(Settings.builder().put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)));
+        assertAcked(prepareCreate("test").setSettings(Settings.builder().put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)));
         ensureGreen();
 
         Script fieldIncScript = new Script(ScriptType.INLINE, UPDATE_SCRIPTS, FIELD_INC_SCRIPT, Collections.singletonMap("field", "field"));
diff --git a/server/src/internalClusterTest/java/org/opensearch/update/UpdateNoopIT.java b/server/src/internalClusterTest/java/org/opensearch/update/UpdateNoopIT.java
index 606a5fe1b7eca..8d66cf998cd7f 100644
--- a/server/src/internalClusterTest/java/org/opensearch/update/UpdateNoopIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/update/UpdateNoopIT.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.action.update.UpdateRequestBuilder;
 import org.opensearch.action.update.UpdateResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.junit.Before;
 
diff --git a/server/src/internalClusterTest/java/org/opensearch/validate/SimpleValidateQueryIT.java b/server/src/internalClusterTest/java/org/opensearch/validate/SimpleValidateQueryIT.java
index 86a51e7367ade..e619b93cdd93b 100644
--- a/server/src/internalClusterTest/java/org/opensearch/validate/SimpleValidateQueryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/validate/SimpleValidateQueryIT.java
@@ -34,10 +34,10 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryResponse;
 import org.opensearch.client.Client;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.MoreLikeThisQueryBuilder.Item;
@@ -48,7 +48,6 @@
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
 import org.opensearch.test.OpenSearchIntegTestCase.Scope;
-
 import org.hamcrest.Matcher;
 
 import java.io.IOException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentDocumentOperationIT.java b/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentDocumentOperationIT.java
index e433a489ad572..9c0a1fa26098c 100644
--- a/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentDocumentOperationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentDocumentOperationIT.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.versioning;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.Map;
@@ -77,9 +77,9 @@ public void onFailure(Exception e) {
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         logger.info("done indexing, check all have the same field value");
-        Map masterSource = client().prepareGet("test", "1").execute().actionGet().getSourceAsMap();
+        Map clusterManagerSource = client().prepareGet("test", "1").execute().actionGet().getSourceAsMap();
         for (int i = 0; i < (cluster().size() * 5); i++) {
-            assertThat(client().prepareGet("test", "1").execute().actionGet().getSourceAsMap(), equalTo(masterSource));
+            assertThat(client().prepareGet("test", "1").execute().actionGet().getSourceAsMap(), equalTo(clusterManagerSource));
         }
     }
 }
diff --git a/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentSeqNoVersioningIT.java b/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentSeqNoVersioningIT.java
index 2194152284d37..c651689e21d3d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentSeqNoVersioningIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/versioning/ConcurrentSeqNoVersioningIT.java
@@ -38,15 +38,15 @@
 import org.opensearch.cluster.coordination.LinearizabilityChecker;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.discovery.AbstractDisruptionTestCase;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.test.OpenSearchIntegTestCase;
diff --git a/server/src/internalClusterTest/java/org/opensearch/versioning/SimpleVersioningIT.java b/server/src/internalClusterTest/java/org/opensearch/versioning/SimpleVersioningIT.java
index 5898bba9762ad..8cd7b419f7989 100644
--- a/server/src/internalClusterTest/java/org/opensearch/versioning/SimpleVersioningIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/versioning/SimpleVersioningIT.java
@@ -32,7 +32,6 @@
 package org.opensearch.versioning;
 
 import org.apache.lucene.tests.util.TestUtil;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkResponse;
@@ -43,6 +42,7 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.test.OpenSearchIntegTestCase;
diff --git a/server/src/main/java/org/apache/lucene/analysis/miscellaneous/DisableGraphAttribute.java b/server/src/main/java/org/apache/lucene/analysis/miscellaneous/DisableGraphAttribute.java
index 01058afa6db96..089d4c1dcfac2 100644
--- a/server/src/main/java/org/apache/lucene/analysis/miscellaneous/DisableGraphAttribute.java
+++ b/server/src/main/java/org/apache/lucene/analysis/miscellaneous/DisableGraphAttribute.java
@@ -33,8 +33,8 @@
 package org.apache.lucene.analysis.miscellaneous;
 
 import org.apache.lucene.analysis.TokenStream;
-import org.apache.lucene.util.Attribute;
 import org.apache.lucene.analysis.tokenattributes.PositionLengthAttribute;
+import org.apache.lucene.util.Attribute;
 
 /**
  * This attribute can be used to indicate that the {@link PositionLengthAttribute}
diff --git a/server/src/main/java/org/apache/lucene/queries/BinaryDocValuesRangeQuery.java b/server/src/main/java/org/apache/lucene/queries/BinaryDocValuesRangeQuery.java
index a2c59de7832d4..963044a3f58d4 100644
--- a/server/src/main/java/org/apache/lucene/queries/BinaryDocValuesRangeQuery.java
+++ b/server/src/main/java/org/apache/lucene/queries/BinaryDocValuesRangeQuery.java
@@ -45,7 +45,7 @@
 import org.apache.lucene.search.TwoPhaseIterator;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
 import org.opensearch.index.mapper.RangeType;
 
 import java.io.IOException;
diff --git a/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java b/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
index 3a36a6ff103e0..345be330f048c 100644
--- a/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
+++ b/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
@@ -35,13 +35,14 @@
 import org.apache.lucene.index.IndexReaderContext;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.index.TermStates;
 import org.apache.lucene.index.TermState;
+import org.apache.lucene.index.TermStates;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.DisjunctionMaxQuery;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.TermQuery;
@@ -93,11 +94,12 @@ public BlendedTermQuery(Term[] terms, float[] boosts) {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query rewritten = super.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query rewritten = super.rewrite(searcher);
         if (rewritten != this) {
             return rewritten;
         }
+        IndexReader reader = searcher.getIndexReader();
         IndexReaderContext context = reader.getContext();
         TermStates[] ctx = new TermStates[terms.length];
         int[] docFreqs = new int[ctx.length];
diff --git a/server/src/main/java/org/apache/lucene/search/grouping/CollapseTopFieldDocs.java b/server/src/main/java/org/apache/lucene/search/grouping/CollapseTopFieldDocs.java
index fe26c313d72b2..e93e5cdcc3f7b 100644
--- a/server/src/main/java/org/apache/lucene/search/grouping/CollapseTopFieldDocs.java
+++ b/server/src/main/java/org/apache/lucene/search/grouping/CollapseTopFieldDocs.java
@@ -39,7 +39,7 @@
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.util.ArrayList;
 import java.util.HashSet;
diff --git a/server/src/main/java/org/apache/lucene/search/uhighlight/CustomUnifiedHighlighter.java b/server/src/main/java/org/apache/lucene/search/uhighlight/CustomUnifiedHighlighter.java
index fb22eb583d9e1..cd4ee121f0f29 100644
--- a/server/src/main/java/org/apache/lucene/search/uhighlight/CustomUnifiedHighlighter.java
+++ b/server/src/main/java/org/apache/lucene/search/uhighlight/CustomUnifiedHighlighter.java
@@ -43,7 +43,6 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.uhighlight.UnifiedHighlighter.HighlightFlag;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.Nullable;
@@ -79,6 +78,7 @@ public class CustomUnifiedHighlighter extends UnifiedHighlighter {
     private final int noMatchSize;
     private final FieldHighlighter fieldHighlighter;
     private final int maxAnalyzedOffset;
+    private final Integer fieldMaxAnalyzedOffset;
 
     /**
      * Creates a new instance of {@link CustomUnifiedHighlighter}
@@ -99,6 +99,7 @@ public class CustomUnifiedHighlighter extends UnifiedHighlighter {
      * @param fieldMatcher decides which terms should be highlighted
      * @param maxAnalyzedOffset if the field is more than this long we'll refuse to use the ANALYZED
      *                          offset source for it because it'd be super slow
+     * @param fieldMaxAnalyzedOffset this is used to limit the length of input that will be ANALYZED, this allows bigger fields to be partially highligthed
      */
     public CustomUnifiedHighlighter(
         IndexSearcher searcher,
@@ -113,7 +114,8 @@ public CustomUnifiedHighlighter(
         int noMatchSize,
         int maxPassages,
         Predicate<String> fieldMatcher,
-        int maxAnalyzedOffset
+        int maxAnalyzedOffset,
+        Integer fieldMaxAnalyzedOffset
     ) throws IOException {
         super(searcher, analyzer);
         this.offsetSource = offsetSource;
@@ -126,6 +128,7 @@ public CustomUnifiedHighlighter(
         this.setFieldMatcher(fieldMatcher);
         this.maxAnalyzedOffset = maxAnalyzedOffset;
         fieldHighlighter = getFieldHighlighter(field, query, extractTerms(query), maxPassages);
+        this.fieldMaxAnalyzedOffset = fieldMaxAnalyzedOffset;
     }
 
     /**
@@ -141,7 +144,21 @@ public Snippet[] highlightField(LeafReader reader, int docId, CheckedSupplier<St
             return null;
         }
         int fieldValueLength = fieldValue.length();
-        if ((offsetSource == OffsetSource.ANALYSIS) && (fieldValueLength > maxAnalyzedOffset)) {
+
+        if (fieldMaxAnalyzedOffset != null && fieldMaxAnalyzedOffset > maxAnalyzedOffset) {
+            throw new IllegalArgumentException(
+                "max_analyzer_offset has exceeded ["
+                    + maxAnalyzedOffset
+                    + "] - maximum allowed to be analyzed for highlighting. "
+                    + "This maximum can be set by changing the ["
+                    + IndexSettings.MAX_ANALYZED_OFFSET_SETTING.getKey()
+                    + "] index level setting. "
+                    + "For large texts, indexing with offsets or term vectors is recommended!"
+            );
+        }
+        // if fieldMaxAnalyzedOffset is not defined
+        // and if this happens we should fallback to the previous behavior
+        if ((offsetSource == OffsetSource.ANALYSIS) && (fieldValueLength > maxAnalyzedOffset && fieldMaxAnalyzedOffset == null)) {
             throw new IllegalArgumentException(
                 "The length of ["
                     + field
diff --git a/server/src/main/java/org/apache/lucene/search/vectorhighlight/CustomFieldQuery.java b/server/src/main/java/org/apache/lucene/search/vectorhighlight/CustomFieldQuery.java
index ac688f15cda01..b8070de81bb3d 100644
--- a/server/src/main/java/org/apache/lucene/search/vectorhighlight/CustomFieldQuery.java
+++ b/server/src/main/java/org/apache/lucene/search/vectorhighlight/CustomFieldQuery.java
@@ -38,6 +38,7 @@
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MultiPhraseQuery;
 import org.apache.lucene.search.PhraseQuery;
 import org.apache.lucene.search.Query;
@@ -66,45 +67,45 @@ public CustomFieldQuery(Query query, IndexReader reader, boolean phraseHighlight
     }
 
     @Override
-    protected void flatten(Query sourceQuery, IndexReader reader, Collection<Query> flatQueries, float boost) throws IOException {
+    protected void flatten(Query sourceQuery, IndexSearcher searcher, Collection<Query> flatQueries, float boost) throws IOException {
         if (sourceQuery instanceof BoostQuery) {
             BoostQuery bq = (BoostQuery) sourceQuery;
             sourceQuery = bq.getQuery();
             boost *= bq.getBoost();
-            flatten(sourceQuery, reader, flatQueries, boost);
+            flatten(sourceQuery, searcher, flatQueries, boost);
         } else if (sourceQuery instanceof SpanTermQuery) {
-            super.flatten(new TermQuery(((SpanTermQuery) sourceQuery).getTerm()), reader, flatQueries, boost);
+            super.flatten(new TermQuery(((SpanTermQuery) sourceQuery).getTerm()), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof ConstantScoreQuery) {
-            flatten(((ConstantScoreQuery) sourceQuery).getQuery(), reader, flatQueries, boost);
+            flatten(((ConstantScoreQuery) sourceQuery).getQuery(), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof FunctionScoreQuery) {
-            flatten(((FunctionScoreQuery) sourceQuery).getSubQuery(), reader, flatQueries, boost);
+            flatten(((FunctionScoreQuery) sourceQuery).getSubQuery(), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof MultiPhrasePrefixQuery) {
-            flatten(sourceQuery.rewrite(reader), reader, flatQueries, boost);
+            flatten(sourceQuery.rewrite(searcher), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof MultiPhraseQuery) {
             MultiPhraseQuery q = ((MultiPhraseQuery) sourceQuery);
-            convertMultiPhraseQuery(0, new int[q.getTermArrays().length], q, q.getTermArrays(), q.getPositions(), reader, flatQueries);
+            convertMultiPhraseQuery(0, new int[q.getTermArrays().length], q, q.getTermArrays(), q.getPositions(), searcher, flatQueries);
         } else if (sourceQuery instanceof BlendedTermQuery) {
             final BlendedTermQuery blendedTermQuery = (BlendedTermQuery) sourceQuery;
-            flatten(blendedTermQuery.rewrite(reader), reader, flatQueries, boost);
+            flatten(blendedTermQuery.rewrite(searcher), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof org.apache.lucene.queries.function.FunctionScoreQuery) {
             org.apache.lucene.queries.function.FunctionScoreQuery funcScoreQuery =
                 (org.apache.lucene.queries.function.FunctionScoreQuery) sourceQuery;
             // flatten query with query boost
-            flatten(funcScoreQuery.getWrappedQuery(), reader, flatQueries, boost);
+            flatten(funcScoreQuery.getWrappedQuery(), searcher, flatQueries, boost);
         } else if (sourceQuery instanceof SynonymQuery) {
             // SynonymQuery should be handled by the parent class directly.
             // This statement should be removed when https://issues.apache.org/jira/browse/LUCENE-7484 is merged.
             SynonymQuery synQuery = (SynonymQuery) sourceQuery;
             for (Term term : synQuery.getTerms()) {
-                flatten(new TermQuery(term), reader, flatQueries, boost);
+                flatten(new TermQuery(term), searcher, flatQueries, boost);
             }
         } else if (sourceQuery instanceof OpenSearchToParentBlockJoinQuery) {
             Query childQuery = ((OpenSearchToParentBlockJoinQuery) sourceQuery).getChildQuery();
             if (childQuery != null) {
-                flatten(childQuery, reader, flatQueries, boost);
+                flatten(childQuery, searcher, flatQueries, boost);
             }
         } else {
-            super.flatten(sourceQuery, reader, flatQueries, boost);
+            super.flatten(sourceQuery, searcher, flatQueries, boost);
         }
     }
 
@@ -114,7 +115,7 @@ private void convertMultiPhraseQuery(
         MultiPhraseQuery orig,
         Term[][] terms,
         int[] pos,
-        IndexReader reader,
+        IndexSearcher searcher,
         Collection<Query> flatQueries
     ) throws IOException {
         if (currentPos == 0) {
@@ -126,7 +127,7 @@ private void convertMultiPhraseQuery(
             if (numTerms > 16) {
                 for (Term[] currentPosTerm : terms) {
                     for (Term term : currentPosTerm) {
-                        super.flatten(new TermQuery(term), reader, flatQueries, 1F);
+                        super.flatten(new TermQuery(term), searcher, flatQueries, 1F);
                     }
                 }
                 return;
@@ -143,12 +144,12 @@ private void convertMultiPhraseQuery(
                 queryBuilder.add(terms[i][termsIdx[i]], pos[i]);
             }
             Query query = queryBuilder.build();
-            this.flatten(query, reader, flatQueries, 1F);
+            this.flatten(query, searcher, flatQueries, 1F);
         } else {
             Term[] t = terms[currentPos];
             for (int i = 0; i < t.length; i++) {
                 termsIdx[currentPos] = i;
-                convertMultiPhraseQuery(currentPos + 1, termsIdx, orig, terms, pos, reader, flatQueries);
+                convertMultiPhraseQuery(currentPos + 1, termsIdx, orig, terms, pos, searcher, flatQueries);
             }
         }
     }
diff --git a/server/src/main/java/org/apache/lucene/util/SPIClassIterator.java b/server/src/main/java/org/apache/lucene/util/SPIClassIterator.java
index 1480c9aeeb2d8..1dea54bcf0176 100644
--- a/server/src/main/java/org/apache/lucene/util/SPIClassIterator.java
+++ b/server/src/main/java/org/apache/lucene/util/SPIClassIterator.java
@@ -30,9 +30,9 @@
 
 package org.apache.lucene.util;
 
+import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
diff --git a/server/src/main/java/org/apache/lucene/util/packed/XPacked64.java b/server/src/main/java/org/apache/lucene/util/packed/XPacked64.java
index d811b245606ba..4777b77cfbfed 100644
--- a/server/src/main/java/org/apache/lucene/util/packed/XPacked64.java
+++ b/server/src/main/java/org/apache/lucene/util/packed/XPacked64.java
@@ -29,11 +29,12 @@
  */
 package org.apache.lucene.util.packed;
 
-import java.io.IOException;
-import java.util.Arrays;
 import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
+import java.io.IOException;
+import java.util.Arrays;
+
 /**
  * Forked from Lucene 8.x; removed in Lucene 9.0
  *
diff --git a/server/src/main/java/org/apache/lucene/util/packed/XPacked64SingleBlock.java b/server/src/main/java/org/apache/lucene/util/packed/XPacked64SingleBlock.java
index ef7644c32a843..0324522e9a68d 100644
--- a/server/src/main/java/org/apache/lucene/util/packed/XPacked64SingleBlock.java
+++ b/server/src/main/java/org/apache/lucene/util/packed/XPacked64SingleBlock.java
@@ -16,11 +16,12 @@
  */
 package org.apache.lucene.util.packed;
 
-import java.io.IOException;
-import java.util.Arrays;
 import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
+import java.io.IOException;
+import java.util.Arrays;
+
 /**
  * Forked from Lucene 8.x; removed in Lucene 9.0
  *
diff --git a/server/src/main/java/org/apache/lucene/util/packed/XPackedInts.java b/server/src/main/java/org/apache/lucene/util/packed/XPackedInts.java
index 9a277a7b5f2f4..f94a4531a7db9 100644
--- a/server/src/main/java/org/apache/lucene/util/packed/XPackedInts.java
+++ b/server/src/main/java/org/apache/lucene/util/packed/XPackedInts.java
@@ -16,9 +16,6 @@
  */
 package org.apache.lucene.util.packed;
 
-import java.io.EOFException;
-import java.io.IOException;
-import java.util.Arrays;
 import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.store.DataInput;
 import org.apache.lucene.store.DataOutput;
@@ -32,6 +29,10 @@
 import org.apache.lucene.util.packed.PackedInts.ReaderIterator;
 import org.apache.lucene.util.packed.PackedInts.Writer;
 
+import java.io.EOFException;
+import java.io.IOException;
+import java.util.Arrays;
+
 /**
  * Forked from Lucene 8.x; removed in Lucene 8.9
  *
diff --git a/server/src/main/java/org/opensearch/OpenSearchCorruptionException.java b/server/src/main/java/org/opensearch/OpenSearchCorruptionException.java
index ecca2191295a4..eb012b209c7de 100644
--- a/server/src/main/java/org/opensearch/OpenSearchCorruptionException.java
+++ b/server/src/main/java/org/opensearch/OpenSearchCorruptionException.java
@@ -36,6 +36,8 @@
 /**
  * This exception is thrown when OpenSearch detects
  * an inconsistency in one of it's persistent files.
+ *
+ * @opensearch.internal
  */
 public class OpenSearchCorruptionException extends IOException {
 
diff --git a/server/src/main/java/org/opensearch/OpenSearchException.java b/server/src/main/java/org/opensearch/OpenSearchException.java
deleted file mode 100644
index 8d3e2569957f1..0000000000000
--- a/server/src/main/java/org/opensearch/OpenSearchException.java
+++ /dev/null
@@ -1,1741 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch;
-
-import org.opensearch.action.support.replication.ReplicationOperation;
-import org.opensearch.cluster.action.shard.ShardStateAction;
-import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.logging.LoggerMessageFormat;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.search.SearchException;
-import org.opensearch.search.aggregations.MultiBucketConsumerService;
-import org.opensearch.transport.TcpTransport;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.regex.Pattern;
-import java.util.stream.Collectors;
-
-import static java.util.Collections.emptyMap;
-import static java.util.Collections.singletonMap;
-import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_UUID_NA_VALUE;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
-
-/**
- * A base class for all opensearch exceptions.
- */
-public class OpenSearchException extends RuntimeException implements ToXContentFragment, Writeable {
-
-    private static final Version UNKNOWN_VERSION_ADDED = Version.fromId(0);
-
-    /**
-     * Passed in the {@link Params} of {@link #generateThrowableXContent(XContentBuilder, Params, Throwable)}
-     * to control if the {@code caused_by} element should render. Unlike most parameters to {@code toXContent} methods this parameter is
-     * internal only and not available as a URL parameter.
-     */
-    private static final String REST_EXCEPTION_SKIP_CAUSE = "rest.exception.cause.skip";
-    /**
-     * Passed in the {@link Params} of {@link #generateThrowableXContent(XContentBuilder, Params, Throwable)}
-     * to control if the {@code stack_trace} element should render. Unlike most parameters to {@code toXContent} methods this parameter is
-     * internal only and not available as a URL parameter. Use the {@code error_trace} parameter instead.
-     */
-    public static final String REST_EXCEPTION_SKIP_STACK_TRACE = "rest.exception.stacktrace.skip";
-    public static final boolean REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT = true;
-    private static final boolean REST_EXCEPTION_SKIP_CAUSE_DEFAULT = false;
-    private static final String INDEX_METADATA_KEY = "opensearch.index";
-    private static final String INDEX_METADATA_KEY_UUID = "opensearch.index_uuid";
-    private static final String SHARD_METADATA_KEY = "opensearch.shard";
-    private static final String RESOURCE_METADATA_TYPE_KEY = "opensearch.resource.type";
-    private static final String RESOURCE_METADATA_ID_KEY = "opensearch.resource.id";
-
-    private static final String TYPE = "type";
-    private static final String REASON = "reason";
-    private static final String CAUSED_BY = "caused_by";
-    private static final ParseField SUPPRESSED = new ParseField("suppressed");
-    public static final String STACK_TRACE = "stack_trace";
-    private static final String HEADER = "header";
-    private static final String ERROR = "error";
-    private static final String ROOT_CAUSE = "root_cause";
-
-    private static final Map<Integer, CheckedFunction<StreamInput, ? extends OpenSearchException, IOException>> ID_TO_SUPPLIER;
-    private static final Map<Class<? extends OpenSearchException>, OpenSearchExceptionHandle> CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE;
-
-    private static final Pattern OS_METADATA = Pattern.compile("^opensearch\\.");
-    private static final Pattern ES_METADATA = Pattern.compile("^es\\.");
-
-    private final Map<String, List<String>> metadata = new HashMap<>();
-    private final Map<String, List<String>> headers = new HashMap<>();
-
-    /**
-     * Construct a <code>OpenSearchException</code> with the specified cause exception.
-     */
-    public OpenSearchException(Throwable cause) {
-        super(cause);
-    }
-
-    /**
-     * Construct a <code>OpenSearchException</code> with the specified detail message.
-     *
-     * The message can be parameterized using <code>{}</code> as placeholders for the given
-     * arguments
-     *
-     * @param msg  the detail message
-     * @param args the arguments for the message
-     */
-    public OpenSearchException(String msg, Object... args) {
-        super(LoggerMessageFormat.format(msg, args));
-    }
-
-    /**
-     * Construct a <code>OpenSearchException</code> with the specified detail message
-     * and nested exception.
-     *
-     * The message can be parameterized using <code>{}</code> as placeholders for the given
-     * arguments
-     *
-     * @param msg   the detail message
-     * @param cause the nested exception
-     * @param args  the arguments for the message
-     */
-    public OpenSearchException(String msg, Throwable cause, Object... args) {
-        super(LoggerMessageFormat.format(msg, args), cause);
-    }
-
-    public OpenSearchException(StreamInput in) throws IOException {
-        super(in.readOptionalString(), in.readException());
-        readStackTrace(this, in);
-        headers.putAll(in.readMapOfLists(StreamInput::readString, StreamInput::readString));
-        metadata.putAll(in.readMapOfLists(OpenSearchException::readAndReplace, StreamInput::readString));
-    }
-
-    private static String readAndReplace(StreamInput in) throws IOException {
-        String str = in.readString();
-        return in.getVersion().onOrBefore(LegacyESVersion.V_7_10_2) ? ES_METADATA.matcher(str).replaceFirst("opensearch.") : str;
-    }
-
-    private static void replaceAndWrite(StreamOutput out, String str) throws IOException {
-        out.writeString(out.getVersion().onOrBefore(LegacyESVersion.V_7_10_2) ? OS_METADATA.matcher(str).replaceFirst("es.") : str);
-    }
-
-    /**
-     * Adds a new piece of metadata with the given key.
-     * If the provided key is already present, the corresponding metadata will be replaced
-     */
-    public void addMetadata(String key, String... values) {
-        addMetadata(key, Arrays.asList(values));
-    }
-
-    /**
-     * Adds a new piece of metadata with the given key.
-     * If the provided key is already present, the corresponding metadata will be replaced
-     */
-    public void addMetadata(String key, List<String> values) {
-        // we need to enforce this otherwise bw comp doesn't work properly, as "opensearch."
-        // was the previous criteria to split headers in two sets
-        if (key.startsWith("opensearch.") == false) {
-            throw new IllegalArgumentException("exception metadata must start with [opensearch.], found [" + key + "] instead");
-        }
-        this.metadata.put(key, values);
-    }
-
-    /**
-     * Returns a set of all metadata keys on this exception
-     */
-    public Set<String> getMetadataKeys() {
-        return metadata.keySet();
-    }
-
-    /**
-     * Returns the list of metadata values for the given key or {@code null} if no metadata for the
-     * given key exists.
-     */
-    public List<String> getMetadata(String key) {
-        return metadata.get(key);
-    }
-
-    protected Map<String, List<String>> getMetadata() {
-        return metadata;
-    }
-
-    /**
-     * Adds a new header with the given key.
-     * This method will replace existing header if a header with the same key already exists
-     */
-    public void addHeader(String key, List<String> value) {
-        // we need to enforce this otherwise bw comp doesn't work properly, as "opensearch."
-        // was the previous criteria to split headers in two sets
-        if (key.startsWith("opensearch.")) {
-            throw new IllegalArgumentException("exception headers must not start with [opensearch.], found [" + key + "] instead");
-        }
-        this.headers.put(key, value);
-    }
-
-    /**
-     * Adds a new header with the given key.
-     * This method will replace existing header if a header with the same key already exists
-     */
-    public void addHeader(String key, String... value) {
-        addHeader(key, Arrays.asList(value));
-    }
-
-    /**
-     * Returns a set of all header keys on this exception
-     */
-    public Set<String> getHeaderKeys() {
-        return headers.keySet();
-    }
-
-    /**
-     * Returns the list of header values for the given key or {@code null} if no header for the
-     * given key exists.
-     */
-    public List<String> getHeader(String key) {
-        return headers.get(key);
-    }
-
-    protected Map<String, List<String>> getHeaders() {
-        return headers;
-    }
-
-    /**
-     * Returns the rest status code associated with this exception.
-     */
-    public RestStatus status() {
-        Throwable cause = unwrapCause();
-        if (cause == this) {
-            return RestStatus.INTERNAL_SERVER_ERROR;
-        } else {
-            return ExceptionsHelper.status(cause);
-        }
-    }
-
-    /**
-     * Unwraps the actual cause from the exception for cases when the exception is a
-     * {@link OpenSearchWrapperException}.
-     *
-     * @see ExceptionsHelper#unwrapCause(Throwable)
-     */
-    public Throwable unwrapCause() {
-        return ExceptionsHelper.unwrapCause(this);
-    }
-
-    /**
-     * Return the detail message, including the message from the nested exception
-     * if there is one.
-     */
-    public String getDetailedMessage() {
-        if (getCause() != null) {
-            StringBuilder sb = new StringBuilder();
-            sb.append(toString()).append("; ");
-            if (getCause() instanceof OpenSearchException) {
-                sb.append(((OpenSearchException) getCause()).getDetailedMessage());
-            } else {
-                sb.append(getCause());
-            }
-            return sb.toString();
-        } else {
-            return super.toString();
-        }
-    }
-
-    /**
-     * Retrieve the innermost cause of this exception, if none, returns the current exception.
-     */
-    public Throwable getRootCause() {
-        Throwable rootCause = this;
-        Throwable cause = getCause();
-        while (cause != null && cause != rootCause) {
-            rootCause = cause;
-            cause = cause.getCause();
-        }
-        return rootCause;
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeOptionalString(this.getMessage());
-        out.writeException(this.getCause());
-        writeStackTraces(this, out, StreamOutput::writeException);
-        out.writeMapOfLists(headers, StreamOutput::writeString, StreamOutput::writeString);
-        out.writeMapOfLists(metadata, OpenSearchException::replaceAndWrite, StreamOutput::writeString);
-    }
-
-    public static OpenSearchException readException(StreamInput input, int id) throws IOException {
-        CheckedFunction<StreamInput, ? extends OpenSearchException, IOException> opensearchException = ID_TO_SUPPLIER.get(id);
-        if (opensearchException == null) {
-            if (id == 127 && input.getVersion().before(LegacyESVersion.V_7_5_0)) {
-                // was SearchContextException
-                return new SearchException(input);
-            }
-            throw new IllegalStateException("unknown exception for id: " + id);
-        }
-        return opensearchException.apply(input);
-    }
-
-    /**
-     * Returns <code>true</code> iff the given class is a registered for an exception to be read.
-     */
-    public static boolean isRegistered(Class<? extends Throwable> exception, Version version) {
-        OpenSearchExceptionHandle openSearchExceptionHandle = CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE.get(exception);
-        if (openSearchExceptionHandle != null) {
-            return version.onOrAfter(openSearchExceptionHandle.versionAdded);
-        }
-        return false;
-    }
-
-    static Set<Class<? extends OpenSearchException>> getRegisteredKeys() { // for testing
-        return CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE.keySet();
-    }
-
-    /**
-     * Returns the serialization id the given exception.
-     */
-    public static int getId(Class<? extends OpenSearchException> exception) {
-        return CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE.get(exception).id;
-    }
-
-    @Override
-    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        Throwable ex = ExceptionsHelper.unwrapCause(this);
-        if (ex != this) {
-            generateThrowableXContent(builder, params, this);
-        } else {
-            innerToXContent(builder, params, this, getExceptionName(), getMessage(), headers, metadata, getCause());
-        }
-        return builder;
-    }
-
-    protected static void innerToXContent(
-        XContentBuilder builder,
-        Params params,
-        Throwable throwable,
-        String type,
-        String message,
-        Map<String, List<String>> headers,
-        Map<String, List<String>> metadata,
-        Throwable cause
-    ) throws IOException {
-        builder.field(TYPE, type);
-        builder.field(REASON, message);
-
-        for (Map.Entry<String, List<String>> entry : metadata.entrySet()) {
-            headerToXContent(builder, entry.getKey().substring("opensearch.".length()), entry.getValue());
-        }
-
-        if (throwable instanceof OpenSearchException) {
-            OpenSearchException exception = (OpenSearchException) throwable;
-            exception.metadataToXContent(builder, params);
-        }
-
-        if (params.paramAsBoolean(REST_EXCEPTION_SKIP_CAUSE, REST_EXCEPTION_SKIP_CAUSE_DEFAULT) == false) {
-            if (cause != null) {
-                builder.field(CAUSED_BY);
-                builder.startObject();
-                generateThrowableXContent(builder, params, cause);
-                builder.endObject();
-            }
-        }
-
-        if (headers.isEmpty() == false) {
-            builder.startObject(HEADER);
-            for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
-                headerToXContent(builder, entry.getKey(), entry.getValue());
-            }
-            builder.endObject();
-        }
-
-        if (params.paramAsBoolean(REST_EXCEPTION_SKIP_STACK_TRACE, REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT) == false) {
-            builder.field(STACK_TRACE, ExceptionsHelper.stackTrace(throwable));
-        }
-
-        Throwable[] allSuppressed = throwable.getSuppressed();
-        if (allSuppressed.length > 0) {
-            builder.startArray(SUPPRESSED.getPreferredName());
-            for (Throwable suppressed : allSuppressed) {
-                builder.startObject();
-                generateThrowableXContent(builder, params, suppressed);
-                builder.endObject();
-            }
-            builder.endArray();
-        }
-    }
-
-    private static void headerToXContent(XContentBuilder builder, String key, List<String> values) throws IOException {
-        if (values != null && values.isEmpty() == false) {
-            if (values.size() == 1) {
-                builder.field(key, values.get(0));
-            } else {
-                builder.startArray(key);
-                for (String value : values) {
-                    builder.value(value);
-                }
-                builder.endArray();
-            }
-        }
-    }
-
-    /**
-     * Renders additional per exception information into the XContent
-     */
-    protected void metadataToXContent(XContentBuilder builder, Params params) throws IOException {}
-
-    /**
-     * Generate a {@link OpenSearchException} from a {@link XContentParser}. This does not
-     * return the original exception type (ie NodeClosedException for example) but just wraps
-     * the type, the reason and the cause of the exception. It also recursively parses the
-     * tree structure of the cause, returning it as a tree structure of {@link OpenSearchException}
-     * instances.
-     */
-    public static OpenSearchException fromXContent(XContentParser parser) throws IOException {
-        XContentParser.Token token = parser.nextToken();
-        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
-        return innerFromXContent(parser, false);
-    }
-
-    public static OpenSearchException innerFromXContent(XContentParser parser, boolean parseRootCauses) throws IOException {
-        XContentParser.Token token = parser.currentToken();
-        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
-
-        String type = null, reason = null, stack = null;
-        OpenSearchException cause = null;
-        Map<String, List<String>> metadata = new HashMap<>();
-        Map<String, List<String>> headers = new HashMap<>();
-        List<OpenSearchException> rootCauses = new ArrayList<>();
-        List<OpenSearchException> suppressed = new ArrayList<>();
-
-        for (; token == XContentParser.Token.FIELD_NAME; token = parser.nextToken()) {
-            String currentFieldName = parser.currentName();
-            token = parser.nextToken();
-
-            if (token.isValue()) {
-                if (TYPE.equals(currentFieldName)) {
-                    type = parser.text();
-                } else if (REASON.equals(currentFieldName)) {
-                    reason = parser.text();
-                } else if (STACK_TRACE.equals(currentFieldName)) {
-                    stack = parser.text();
-                } else if (token == XContentParser.Token.VALUE_STRING) {
-                    metadata.put(currentFieldName, Collections.singletonList(parser.text()));
-                }
-            } else if (token == XContentParser.Token.START_OBJECT) {
-                if (CAUSED_BY.equals(currentFieldName)) {
-                    cause = fromXContent(parser);
-                } else if (HEADER.equals(currentFieldName)) {
-                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
-                        if (token == XContentParser.Token.FIELD_NAME) {
-                            currentFieldName = parser.currentName();
-                        } else {
-                            List<String> values = headers.getOrDefault(currentFieldName, new ArrayList<>());
-                            if (token == XContentParser.Token.VALUE_STRING) {
-                                values.add(parser.text());
-                            } else if (token == XContentParser.Token.START_ARRAY) {
-                                while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-                                    if (token == XContentParser.Token.VALUE_STRING) {
-                                        values.add(parser.text());
-                                    } else {
-                                        parser.skipChildren();
-                                    }
-                                }
-                            } else if (token == XContentParser.Token.START_OBJECT) {
-                                parser.skipChildren();
-                            }
-                            headers.put(currentFieldName, values);
-                        }
-                    }
-                } else {
-                    // Any additional metadata object added by the metadataToXContent method is ignored
-                    // and skipped, so that the parser does not fail on unknown fields. The parser only
-                    // support metadata key-pairs and metadata arrays of values.
-                    parser.skipChildren();
-                }
-            } else if (token == XContentParser.Token.START_ARRAY) {
-                if (parseRootCauses && ROOT_CAUSE.equals(currentFieldName)) {
-                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-                        rootCauses.add(fromXContent(parser));
-                    }
-                } else if (SUPPRESSED.match(currentFieldName, parser.getDeprecationHandler())) {
-                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-                        suppressed.add(fromXContent(parser));
-                    }
-                } else {
-                    // Parse the array and add each item to the corresponding list of metadata.
-                    // Arrays of objects are not supported yet and just ignored and skipped.
-                    List<String> values = new ArrayList<>();
-                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-                        if (token == XContentParser.Token.VALUE_STRING) {
-                            values.add(parser.text());
-                        } else {
-                            parser.skipChildren();
-                        }
-                    }
-                    if (values.size() > 0) {
-                        if (metadata.containsKey(currentFieldName)) {
-                            values.addAll(metadata.get(currentFieldName));
-                        }
-                        metadata.put(currentFieldName, values);
-                    }
-                }
-            }
-        }
-
-        OpenSearchException e = new OpenSearchException(buildMessage(type, reason, stack), cause);
-        for (Map.Entry<String, List<String>> entry : metadata.entrySet()) {
-            // subclasses can print out additional metadata through the metadataToXContent method. Simple key-value pairs will be
-            // parsed back and become part of this metadata set, while objects and arrays are not supported when parsing back.
-            // Those key-value pairs become part of the metadata set and inherit the "opensearch." prefix as that is currently required
-            // by addMetadata. The prefix will get stripped out when printing metadata out so it will be effectively invisible.
-            // TODO move subclasses that print out simple metadata to using addMetadata directly and support also numbers and booleans.
-            // TODO rename metadataToXContent and have only SearchPhaseExecutionException use it, which prints out complex objects
-            e.addMetadata("opensearch." + entry.getKey(), entry.getValue());
-        }
-        for (Map.Entry<String, List<String>> header : headers.entrySet()) {
-            e.addHeader(header.getKey(), header.getValue());
-        }
-
-        // Adds root causes as suppressed exception. This way they are not lost
-        // after parsing and can be retrieved using getSuppressed() method.
-        for (OpenSearchException rootCause : rootCauses) {
-            e.addSuppressed(rootCause);
-        }
-        for (OpenSearchException s : suppressed) {
-            e.addSuppressed(s);
-        }
-        return e;
-    }
-
-    /**
-     * Static toXContent helper method that renders {@link OpenSearchException} or {@link Throwable} instances
-     * as XContent, delegating the rendering to {@link #toXContent(XContentBuilder, Params)}
-     * or {@link #innerToXContent(XContentBuilder, Params, Throwable, String, String, Map, Map, Throwable)}.
-     *
-     * This method is usually used when the {@link Throwable} is rendered as a part of another XContent object, and its result can
-     * be parsed back using the {@link #fromXContent(XContentParser)} method.
-     */
-    public static void generateThrowableXContent(XContentBuilder builder, Params params, Throwable t) throws IOException {
-        t = ExceptionsHelper.unwrapCause(t);
-
-        if (t instanceof OpenSearchException) {
-            ((OpenSearchException) t).toXContent(builder, params);
-        } else {
-            innerToXContent(builder, params, t, getExceptionName(t), t.getMessage(), emptyMap(), emptyMap(), t.getCause());
-        }
-    }
-
-    /**
-     * Render any exception as a xcontent, encapsulated within a field or object named "error". The level of details that are rendered
-     * depends on the value of the "detailed" parameter: when it's false only a simple message based on the type and message of the
-     * exception is rendered. When it's true all detail are provided including guesses root causes, cause and potentially stack
-     * trace.
-     *
-     * This method is usually used when the {@link Exception} is rendered as a full XContent object, and its output can be parsed
-     * by the {@link #failureFromXContent(XContentParser)} method.
-     */
-    public static void generateFailureXContent(XContentBuilder builder, Params params, @Nullable Exception e, boolean detailed)
-        throws IOException {
-        // No exception to render as an error
-        if (e == null) {
-            builder.field(ERROR, "unknown");
-            return;
-        }
-
-        // Render the exception with a simple message
-        if (detailed == false) {
-            String message = "No OpenSearchException found";
-            Throwable t = e;
-            for (int counter = 0; counter < 10 && t != null; counter++) {
-                if (t instanceof OpenSearchException) {
-                    message = t.getClass().getSimpleName() + "[" + t.getMessage() + "]";
-                    break;
-                }
-                t = t.getCause();
-            }
-            builder.field(ERROR, message);
-            return;
-        }
-
-        // Render the exception with all details
-        final OpenSearchException[] rootCauses = OpenSearchException.guessRootCauses(e);
-        builder.startObject(ERROR);
-        {
-            builder.startArray(ROOT_CAUSE);
-            for (OpenSearchException rootCause : rootCauses) {
-                builder.startObject();
-                rootCause.toXContent(builder, new DelegatingMapParams(singletonMap(REST_EXCEPTION_SKIP_CAUSE, "true"), params));
-                builder.endObject();
-            }
-            builder.endArray();
-        }
-        generateThrowableXContent(builder, params, e);
-        builder.endObject();
-    }
-
-    /**
-     * Parses the output of {@link #generateFailureXContent(XContentBuilder, Params, Exception, boolean)}
-     */
-    public static OpenSearchException failureFromXContent(XContentParser parser) throws IOException {
-        XContentParser.Token token = parser.currentToken();
-        ensureFieldName(parser, token, ERROR);
-
-        token = parser.nextToken();
-        if (token.isValue()) {
-            return new OpenSearchException(buildMessage("exception", parser.text(), null));
-        }
-
-        ensureExpectedToken(XContentParser.Token.START_OBJECT, token, parser);
-        token = parser.nextToken();
-
-        // Root causes are parsed in the innerFromXContent() and are added as suppressed exceptions.
-        return innerFromXContent(parser, true);
-    }
-
-    /**
-     * Returns the root cause of this exception or multiple if different shards caused different exceptions
-     */
-    public OpenSearchException[] guessRootCauses() {
-        final Throwable cause = getCause();
-        if (cause != null && cause instanceof OpenSearchException) {
-            return ((OpenSearchException) cause).guessRootCauses();
-        }
-        return new OpenSearchException[] { this };
-    }
-
-    /**
-     * Returns the root cause of this exception or multiple if different shards caused different exceptions.
-     * If the given exception is not an instance of {@link OpenSearchException} an empty array
-     * is returned.
-     */
-    public static OpenSearchException[] guessRootCauses(Throwable t) {
-        Throwable ex = ExceptionsHelper.unwrapCause(t);
-        if (ex instanceof OpenSearchException) {
-            // OpenSearchException knows how to guess its own root cause
-            return ((OpenSearchException) ex).guessRootCauses();
-        }
-        if (ex instanceof XContentParseException) {
-            /*
-             * We'd like to unwrap parsing exceptions to the inner-most
-             * parsing exception because that is generally the most interesting
-             * exception to return to the user. If that exception is caused by
-             * an OpenSearchException we'd like to keep unwrapping because
-             * ElasticserachExceptions tend to contain useful information for
-             * the user.
-             */
-            Throwable cause = ex.getCause();
-            if (cause != null) {
-                if (cause instanceof XContentParseException || cause instanceof OpenSearchException) {
-                    return guessRootCauses(ex.getCause());
-                }
-            }
-        }
-        return new OpenSearchException[] { new OpenSearchException(ex.getMessage(), ex) {
-            @Override
-            protected String getExceptionName() {
-                return getExceptionName(getCause());
-            }
-        } };
-    }
-
-    protected String getExceptionName() {
-        return getExceptionName(this);
-    }
-
-    /**
-     * Returns an underscore case name for the given exception. This method strips {@code OpenSearch} prefixes from exception names.
-     */
-    public static String getExceptionName(Throwable ex) {
-        String simpleName = ex.getClass().getSimpleName();
-        if (simpleName.startsWith("OpenSearch")) {
-            simpleName = simpleName.substring("OpenSearch".length());
-        }
-        // TODO: do we really need to make the exception name in underscore casing?
-        return toUnderscoreCase(simpleName);
-    }
-
-    static String buildMessage(String type, String reason, String stack) {
-        StringBuilder message = new StringBuilder("OpenSearch exception [");
-        message.append(TYPE).append('=').append(type).append(", ");
-        message.append(REASON).append('=').append(reason);
-        if (stack != null) {
-            message.append(", ").append(STACK_TRACE).append('=').append(stack);
-        }
-        message.append(']');
-        return message.toString();
-    }
-
-    @Override
-    public String toString() {
-        StringBuilder builder = new StringBuilder();
-        if (metadata.containsKey(INDEX_METADATA_KEY)) {
-            builder.append(getIndex());
-            if (metadata.containsKey(SHARD_METADATA_KEY)) {
-                builder.append('[').append(getShardId()).append(']');
-            }
-            builder.append(' ');
-        }
-        return builder.append(ExceptionsHelper.detailedMessage(this).trim()).toString();
-    }
-
-    /**
-     * Deserializes stacktrace elements as well as suppressed exceptions from the given output stream and
-     * adds it to the given exception.
-     */
-    public static <T extends Throwable> T readStackTrace(T throwable, StreamInput in) throws IOException {
-        throwable.setStackTrace(in.readArray(i -> {
-            final String declaringClasss = i.readString();
-            final String fileName = i.readOptionalString();
-            final String methodName = i.readString();
-            final int lineNumber = i.readVInt();
-            return new StackTraceElement(declaringClasss, methodName, fileName, lineNumber);
-        }, StackTraceElement[]::new));
-
-        int numSuppressed = in.readVInt();
-        for (int i = 0; i < numSuppressed; i++) {
-            throwable.addSuppressed(in.readException());
-        }
-        return throwable;
-    }
-
-    /**
-     * Serializes the given exceptions stacktrace elements as well as it's suppressed exceptions to the given output stream.
-     */
-    public static <T extends Throwable> T writeStackTraces(T throwable, StreamOutput out, Writer<Throwable> exceptionWriter)
-        throws IOException {
-        out.writeArray((o, v) -> {
-            o.writeString(v.getClassName());
-            o.writeOptionalString(v.getFileName());
-            o.writeString(v.getMethodName());
-            o.writeVInt(v.getLineNumber());
-        }, throwable.getStackTrace());
-        out.writeArray(exceptionWriter, throwable.getSuppressed());
-        return throwable;
-    }
-
-    /**
-     * This is the list of Exceptions OpenSearch can throw over the wire or save into a corruption marker. Each value in the enum is a
-     * single exception tying the Class to an id for use of the encode side and the id back to a constructor for use on the decode side. As
-     * such its ok if the exceptions to change names so long as their constructor can still read the exception. Each exception is listed
-     * in id order below. If you want to remove an exception leave a tombstone comment and mark the id as null in
-     * ExceptionSerializationTests.testIds.ids.
-     */
-    private enum OpenSearchExceptionHandle {
-        INDEX_SHARD_SNAPSHOT_FAILED_EXCEPTION(
-            org.opensearch.index.snapshots.IndexShardSnapshotFailedException.class,
-            org.opensearch.index.snapshots.IndexShardSnapshotFailedException::new,
-            0,
-            UNKNOWN_VERSION_ADDED
-        ),
-        DFS_PHASE_EXECUTION_EXCEPTION(
-            org.opensearch.search.dfs.DfsPhaseExecutionException.class,
-            org.opensearch.search.dfs.DfsPhaseExecutionException::new,
-            1,
-            UNKNOWN_VERSION_ADDED
-        ),
-        EXECUTION_CANCELLED_EXCEPTION(
-            org.opensearch.common.util.CancellableThreads.ExecutionCancelledException.class,
-            org.opensearch.common.util.CancellableThreads.ExecutionCancelledException::new,
-            2,
-            UNKNOWN_VERSION_ADDED
-        ),
-        MASTER_NOT_DISCOVERED_EXCEPTION(
-            org.opensearch.discovery.MasterNotDiscoveredException.class,
-            org.opensearch.discovery.MasterNotDiscoveredException::new,
-            3,
-            UNKNOWN_VERSION_ADDED
-        ),
-        OPENSEARCH_SECURITY_EXCEPTION(
-            org.opensearch.OpenSearchSecurityException.class,
-            org.opensearch.OpenSearchSecurityException::new,
-            4,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_RESTORE_EXCEPTION(
-            org.opensearch.index.snapshots.IndexShardRestoreException.class,
-            org.opensearch.index.snapshots.IndexShardRestoreException::new,
-            5,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_CLOSED_EXCEPTION(
-            org.opensearch.indices.IndexClosedException.class,
-            org.opensearch.indices.IndexClosedException::new,
-            6,
-            UNKNOWN_VERSION_ADDED
-        ),
-        BIND_HTTP_EXCEPTION(
-            org.opensearch.http.BindHttpException.class,
-            org.opensearch.http.BindHttpException::new,
-            7,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REDUCE_SEARCH_PHASE_EXCEPTION(
-            org.opensearch.action.search.ReduceSearchPhaseException.class,
-            org.opensearch.action.search.ReduceSearchPhaseException::new,
-            8,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NODE_CLOSED_EXCEPTION(
-            org.opensearch.node.NodeClosedException.class,
-            org.opensearch.node.NodeClosedException::new,
-            9,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SNAPSHOT_FAILED_ENGINE_EXCEPTION(
-            org.opensearch.index.engine.SnapshotFailedEngineException.class,
-            org.opensearch.index.engine.SnapshotFailedEngineException::new,
-            10,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SHARD_NOT_FOUND_EXCEPTION(
-            org.opensearch.index.shard.ShardNotFoundException.class,
-            org.opensearch.index.shard.ShardNotFoundException::new,
-            11,
-            UNKNOWN_VERSION_ADDED
-        ),
-        CONNECT_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.ConnectTransportException.class,
-            org.opensearch.transport.ConnectTransportException::new,
-            12,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NOT_SERIALIZABLE_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.NotSerializableTransportException.class,
-            org.opensearch.transport.NotSerializableTransportException::new,
-            13,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RESPONSE_HANDLER_FAILURE_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.ResponseHandlerFailureTransportException.class,
-            org.opensearch.transport.ResponseHandlerFailureTransportException::new,
-            14,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_CREATION_EXCEPTION(
-            org.opensearch.indices.IndexCreationException.class,
-            org.opensearch.indices.IndexCreationException::new,
-            15,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_NOT_FOUND_EXCEPTION(
-            org.opensearch.index.IndexNotFoundException.class,
-            org.opensearch.index.IndexNotFoundException::new,
-            16,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ILLEGAL_SHARD_ROUTING_STATE_EXCEPTION(
-            org.opensearch.cluster.routing.IllegalShardRoutingStateException.class,
-            org.opensearch.cluster.routing.IllegalShardRoutingStateException::new,
-            17,
-            UNKNOWN_VERSION_ADDED
-        ),
-        BROADCAST_SHARD_OPERATION_FAILED_EXCEPTION(
-            org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException.class,
-            org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException::new,
-            18,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RESOURCE_NOT_FOUND_EXCEPTION(
-            org.opensearch.ResourceNotFoundException.class,
-            org.opensearch.ResourceNotFoundException::new,
-            19,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ACTION_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.ActionTransportException.class,
-            org.opensearch.transport.ActionTransportException::new,
-            20,
-            UNKNOWN_VERSION_ADDED
-        ),
-        OPENSEARCH_GENERATION_EXCEPTION(
-            org.opensearch.OpenSearchGenerationException.class,
-            org.opensearch.OpenSearchGenerationException::new,
-            21,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 22 was CreateFailedEngineException
-        INDEX_SHARD_STARTED_EXCEPTION(
-            org.opensearch.index.shard.IndexShardStartedException.class,
-            org.opensearch.index.shard.IndexShardStartedException::new,
-            23,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SEARCH_CONTEXT_MISSING_EXCEPTION(
-            org.opensearch.search.SearchContextMissingException.class,
-            org.opensearch.search.SearchContextMissingException::new,
-            24,
-            UNKNOWN_VERSION_ADDED
-        ),
-        GENERAL_SCRIPT_EXCEPTION(
-            org.opensearch.script.GeneralScriptException.class,
-            org.opensearch.script.GeneralScriptException::new,
-            25,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 26 was BatchOperationException
-        SNAPSHOT_CREATION_EXCEPTION(
-            org.opensearch.snapshots.SnapshotCreationException.class,
-            org.opensearch.snapshots.SnapshotCreationException::new,
-            27,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 28 was DeleteFailedEngineException, deprecated in 6.0, removed in 7.0
-        DOCUMENT_MISSING_EXCEPTION(
-            org.opensearch.index.engine.DocumentMissingException.class,
-            org.opensearch.index.engine.DocumentMissingException::new,
-            29,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SNAPSHOT_EXCEPTION(
-            org.opensearch.snapshots.SnapshotException.class,
-            org.opensearch.snapshots.SnapshotException::new,
-            30,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INVALID_ALIAS_NAME_EXCEPTION(
-            org.opensearch.indices.InvalidAliasNameException.class,
-            org.opensearch.indices.InvalidAliasNameException::new,
-            31,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INVALID_INDEX_NAME_EXCEPTION(
-            org.opensearch.indices.InvalidIndexNameException.class,
-            org.opensearch.indices.InvalidIndexNameException::new,
-            32,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_PRIMARY_SHARD_NOT_ALLOCATED_EXCEPTION(
-            org.opensearch.indices.IndexPrimaryShardNotAllocatedException.class,
-            org.opensearch.indices.IndexPrimaryShardNotAllocatedException::new,
-            33,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TRANSPORT_EXCEPTION(
-            org.opensearch.transport.TransportException.class,
-            org.opensearch.transport.TransportException::new,
-            34,
-            UNKNOWN_VERSION_ADDED
-        ),
-        OPENSEARCH_PARSE_EXCEPTION(
-            org.opensearch.OpenSearchParseException.class,
-            org.opensearch.OpenSearchParseException::new,
-            35,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SEARCH_EXCEPTION(
-            org.opensearch.search.SearchException.class,
-            org.opensearch.search.SearchException::new,
-            36,
-            UNKNOWN_VERSION_ADDED
-        ),
-        MAPPER_EXCEPTION(
-            org.opensearch.index.mapper.MapperException.class,
-            org.opensearch.index.mapper.MapperException::new,
-            37,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INVALID_TYPE_NAME_EXCEPTION(
-            org.opensearch.indices.InvalidTypeNameException.class,
-            org.opensearch.indices.InvalidTypeNameException::new,
-            38,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SNAPSHOT_RESTORE_EXCEPTION(
-            org.opensearch.snapshots.SnapshotRestoreException.class,
-            org.opensearch.snapshots.SnapshotRestoreException::new,
-            39,
-            UNKNOWN_VERSION_ADDED
-        ),
-        PARSING_EXCEPTION(
-            org.opensearch.common.ParsingException.class,
-            org.opensearch.common.ParsingException::new,
-            40,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_CLOSED_EXCEPTION(
-            org.opensearch.index.shard.IndexShardClosedException.class,
-            org.opensearch.index.shard.IndexShardClosedException::new,
-            41,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RECOVER_FILES_RECOVERY_EXCEPTION(
-            org.opensearch.indices.recovery.RecoverFilesRecoveryException.class,
-            org.opensearch.indices.recovery.RecoverFilesRecoveryException::new,
-            42,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TRUNCATED_TRANSLOG_EXCEPTION(
-            org.opensearch.index.translog.TruncatedTranslogException.class,
-            org.opensearch.index.translog.TruncatedTranslogException::new,
-            43,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RECOVERY_FAILED_EXCEPTION(
-            org.opensearch.indices.recovery.RecoveryFailedException.class,
-            org.opensearch.indices.recovery.RecoveryFailedException::new,
-            44,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_RELOCATED_EXCEPTION(
-            org.opensearch.index.shard.IndexShardRelocatedException.class,
-            org.opensearch.index.shard.IndexShardRelocatedException::new,
-            45,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NODE_SHOULD_NOT_CONNECT_EXCEPTION(
-            org.opensearch.transport.NodeShouldNotConnectException.class,
-            org.opensearch.transport.NodeShouldNotConnectException::new,
-            46,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 47 used to be for IndexTemplateAlreadyExistsException which was deprecated in 5.1 removed in 6.0
-        TRANSLOG_CORRUPTED_EXCEPTION(
-            org.opensearch.index.translog.TranslogCorruptedException.class,
-            org.opensearch.index.translog.TranslogCorruptedException::new,
-            48,
-            UNKNOWN_VERSION_ADDED
-        ),
-        CLUSTER_BLOCK_EXCEPTION(
-            org.opensearch.cluster.block.ClusterBlockException.class,
-            org.opensearch.cluster.block.ClusterBlockException::new,
-            49,
-            UNKNOWN_VERSION_ADDED
-        ),
-        FETCH_PHASE_EXECUTION_EXCEPTION(
-            org.opensearch.search.fetch.FetchPhaseExecutionException.class,
-            org.opensearch.search.fetch.FetchPhaseExecutionException::new,
-            50,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 51 used to be for IndexShardAlreadyExistsException which was deprecated in 5.1 removed in 6.0
-        VERSION_CONFLICT_ENGINE_EXCEPTION(
-            org.opensearch.index.engine.VersionConflictEngineException.class,
-            org.opensearch.index.engine.VersionConflictEngineException::new,
-            52,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ENGINE_EXCEPTION(
-            org.opensearch.index.engine.EngineException.class,
-            org.opensearch.index.engine.EngineException::new,
-            53,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 54 was DocumentAlreadyExistsException, which is superseded by VersionConflictEngineException
-        NO_SUCH_NODE_EXCEPTION(
-            org.opensearch.action.NoSuchNodeException.class,
-            org.opensearch.action.NoSuchNodeException::new,
-            55,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SETTINGS_EXCEPTION(
-            org.opensearch.common.settings.SettingsException.class,
-            org.opensearch.common.settings.SettingsException::new,
-            56,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_TEMPLATE_MISSING_EXCEPTION(
-            org.opensearch.indices.IndexTemplateMissingException.class,
-            org.opensearch.indices.IndexTemplateMissingException::new,
-            57,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SEND_REQUEST_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.SendRequestTransportException.class,
-            org.opensearch.transport.SendRequestTransportException::new,
-            58,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 59 used to be OpenSearchRejectedExecutionException
-        // 60 used to be for EarlyTerminationException
-        // 61 used to be for RoutingValidationException
-        NOT_SERIALIZABLE_EXCEPTION_WRAPPER(
-            org.opensearch.common.io.stream.NotSerializableExceptionWrapper.class,
-            org.opensearch.common.io.stream.NotSerializableExceptionWrapper::new,
-            62,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ALIAS_FILTER_PARSING_EXCEPTION(
-            org.opensearch.indices.AliasFilterParsingException.class,
-            org.opensearch.indices.AliasFilterParsingException::new,
-            63,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 64 was DeleteByQueryFailedEngineException, which was removed in 5.0
-        GATEWAY_EXCEPTION(
-            org.opensearch.gateway.GatewayException.class,
-            org.opensearch.gateway.GatewayException::new,
-            65,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_NOT_RECOVERING_EXCEPTION(
-            org.opensearch.index.shard.IndexShardNotRecoveringException.class,
-            org.opensearch.index.shard.IndexShardNotRecoveringException::new,
-            66,
-            UNKNOWN_VERSION_ADDED
-        ),
-        HTTP_EXCEPTION(org.opensearch.http.HttpException.class, org.opensearch.http.HttpException::new, 67, UNKNOWN_VERSION_ADDED),
-        OPENSEARCH_EXCEPTION(OpenSearchException.class, OpenSearchException::new, 68, UNKNOWN_VERSION_ADDED),
-        SNAPSHOT_MISSING_EXCEPTION(
-            org.opensearch.snapshots.SnapshotMissingException.class,
-            org.opensearch.snapshots.SnapshotMissingException::new,
-            69,
-            UNKNOWN_VERSION_ADDED
-        ),
-        PRIMARY_MISSING_ACTION_EXCEPTION(
-            org.opensearch.action.PrimaryMissingActionException.class,
-            org.opensearch.action.PrimaryMissingActionException::new,
-            70,
-            UNKNOWN_VERSION_ADDED
-        ),
-        FAILED_NODE_EXCEPTION(
-            org.opensearch.action.FailedNodeException.class,
-            org.opensearch.action.FailedNodeException::new,
-            71,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SEARCH_PARSE_EXCEPTION(
-            org.opensearch.search.SearchParseException.class,
-            org.opensearch.search.SearchParseException::new,
-            72,
-            UNKNOWN_VERSION_ADDED
-        ),
-        CONCURRENT_SNAPSHOT_EXECUTION_EXCEPTION(
-            org.opensearch.snapshots.ConcurrentSnapshotExecutionException.class,
-            org.opensearch.snapshots.ConcurrentSnapshotExecutionException::new,
-            73,
-            UNKNOWN_VERSION_ADDED
-        ),
-        BLOB_STORE_EXCEPTION(
-            org.opensearch.common.blobstore.BlobStoreException.class,
-            org.opensearch.common.blobstore.BlobStoreException::new,
-            74,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INCOMPATIBLE_CLUSTER_STATE_VERSION_EXCEPTION(
-            org.opensearch.cluster.IncompatibleClusterStateVersionException.class,
-            org.opensearch.cluster.IncompatibleClusterStateVersionException::new,
-            75,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RECOVERY_ENGINE_EXCEPTION(
-            org.opensearch.index.engine.RecoveryEngineException.class,
-            org.opensearch.index.engine.RecoveryEngineException::new,
-            76,
-            UNKNOWN_VERSION_ADDED
-        ),
-        UNCATEGORIZED_EXECUTION_EXCEPTION(
-            org.opensearch.common.util.concurrent.UncategorizedExecutionException.class,
-            org.opensearch.common.util.concurrent.UncategorizedExecutionException::new,
-            77,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TIMESTAMP_PARSING_EXCEPTION(
-            org.opensearch.action.TimestampParsingException.class,
-            org.opensearch.action.TimestampParsingException::new,
-            78,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ROUTING_MISSING_EXCEPTION(
-            org.opensearch.action.RoutingMissingException.class,
-            org.opensearch.action.RoutingMissingException::new,
-            79,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 80 was IndexFailedEngineException, deprecated in 6.0, removed in 7.0
-        INDEX_SHARD_RESTORE_FAILED_EXCEPTION(
-            org.opensearch.index.snapshots.IndexShardRestoreFailedException.class,
-            org.opensearch.index.snapshots.IndexShardRestoreFailedException::new,
-            81,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REPOSITORY_EXCEPTION(
-            org.opensearch.repositories.RepositoryException.class,
-            org.opensearch.repositories.RepositoryException::new,
-            82,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RECEIVE_TIMEOUT_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.ReceiveTimeoutTransportException.class,
-            org.opensearch.transport.ReceiveTimeoutTransportException::new,
-            83,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NODE_DISCONNECTED_EXCEPTION(
-            org.opensearch.transport.NodeDisconnectedException.class,
-            org.opensearch.transport.NodeDisconnectedException::new,
-            84,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 85 used to be for AlreadyExpiredException
-        AGGREGATION_EXECUTION_EXCEPTION(
-            org.opensearch.search.aggregations.AggregationExecutionException.class,
-            org.opensearch.search.aggregations.AggregationExecutionException::new,
-            86,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 87 used to be for MergeMappingException
-        INVALID_INDEX_TEMPLATE_EXCEPTION(
-            org.opensearch.indices.InvalidIndexTemplateException.class,
-            org.opensearch.indices.InvalidIndexTemplateException::new,
-            88,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REFRESH_FAILED_ENGINE_EXCEPTION(
-            org.opensearch.index.engine.RefreshFailedEngineException.class,
-            org.opensearch.index.engine.RefreshFailedEngineException::new,
-            90,
-            UNKNOWN_VERSION_ADDED
-        ),
-        AGGREGATION_INITIALIZATION_EXCEPTION(
-            org.opensearch.search.aggregations.AggregationInitializationException.class,
-            org.opensearch.search.aggregations.AggregationInitializationException::new,
-            91,
-            UNKNOWN_VERSION_ADDED
-        ),
-        DELAY_RECOVERY_EXCEPTION(
-            org.opensearch.indices.recovery.DelayRecoveryException.class,
-            org.opensearch.indices.recovery.DelayRecoveryException::new,
-            92,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 93 used to be for IndexWarmerMissingException
-        NO_NODE_AVAILABLE_EXCEPTION(
-            org.opensearch.client.transport.NoNodeAvailableException.class,
-            org.opensearch.client.transport.NoNodeAvailableException::new,
-            94,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INVALID_SNAPSHOT_NAME_EXCEPTION(
-            org.opensearch.snapshots.InvalidSnapshotNameException.class,
-            org.opensearch.snapshots.InvalidSnapshotNameException::new,
-            96,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ILLEGAL_INDEX_SHARD_STATE_EXCEPTION(
-            org.opensearch.index.shard.IllegalIndexShardStateException.class,
-            org.opensearch.index.shard.IllegalIndexShardStateException::new,
-            97,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_SNAPSHOT_EXCEPTION(
-            org.opensearch.index.snapshots.IndexShardSnapshotException.class,
-            org.opensearch.index.snapshots.IndexShardSnapshotException::new,
-            98,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_NOT_STARTED_EXCEPTION(
-            org.opensearch.index.shard.IndexShardNotStartedException.class,
-            org.opensearch.index.shard.IndexShardNotStartedException::new,
-            99,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SEARCH_PHASE_EXECUTION_EXCEPTION(
-            org.opensearch.action.search.SearchPhaseExecutionException.class,
-            org.opensearch.action.search.SearchPhaseExecutionException::new,
-            100,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ACTION_NOT_FOUND_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.ActionNotFoundTransportException.class,
-            org.opensearch.transport.ActionNotFoundTransportException::new,
-            101,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TRANSPORT_SERIALIZATION_EXCEPTION(
-            org.opensearch.transport.TransportSerializationException.class,
-            org.opensearch.transport.TransportSerializationException::new,
-            102,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REMOTE_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.RemoteTransportException.class,
-            org.opensearch.transport.RemoteTransportException::new,
-            103,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ENGINE_CREATION_FAILURE_EXCEPTION(
-            org.opensearch.index.engine.EngineCreationFailureException.class,
-            org.opensearch.index.engine.EngineCreationFailureException::new,
-            104,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ROUTING_EXCEPTION(
-            org.opensearch.cluster.routing.RoutingException.class,
-            org.opensearch.cluster.routing.RoutingException::new,
-            105,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_RECOVERY_EXCEPTION(
-            org.opensearch.index.shard.IndexShardRecoveryException.class,
-            org.opensearch.index.shard.IndexShardRecoveryException::new,
-            106,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REPOSITORY_MISSING_EXCEPTION(
-            org.opensearch.repositories.RepositoryMissingException.class,
-            org.opensearch.repositories.RepositoryMissingException::new,
-            107,
-            UNKNOWN_VERSION_ADDED
-        ),
-        DOCUMENT_SOURCE_MISSING_EXCEPTION(
-            org.opensearch.index.engine.DocumentSourceMissingException.class,
-            org.opensearch.index.engine.DocumentSourceMissingException::new,
-            109,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 110 used to be FlushNotAllowedEngineException
-        NO_CLASS_SETTINGS_EXCEPTION(
-            org.opensearch.common.settings.NoClassSettingsException.class,
-            org.opensearch.common.settings.NoClassSettingsException::new,
-            111,
-            UNKNOWN_VERSION_ADDED
-        ),
-        BIND_TRANSPORT_EXCEPTION(
-            org.opensearch.transport.BindTransportException.class,
-            org.opensearch.transport.BindTransportException::new,
-            112,
-            UNKNOWN_VERSION_ADDED
-        ),
-        ALIASES_NOT_FOUND_EXCEPTION(
-            org.opensearch.rest.action.admin.indices.AliasesNotFoundException.class,
-            org.opensearch.rest.action.admin.indices.AliasesNotFoundException::new,
-            113,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INDEX_SHARD_RECOVERING_EXCEPTION(
-            org.opensearch.index.shard.IndexShardRecoveringException.class,
-            org.opensearch.index.shard.IndexShardRecoveringException::new,
-            114,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TRANSLOG_EXCEPTION(
-            org.opensearch.index.translog.TranslogException.class,
-            org.opensearch.index.translog.TranslogException::new,
-            115,
-            UNKNOWN_VERSION_ADDED
-        ),
-        PROCESS_CLUSTER_EVENT_TIMEOUT_EXCEPTION(
-            org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException.class,
-            org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException::new,
-            116,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RETRY_ON_PRIMARY_EXCEPTION(
-            ReplicationOperation.RetryOnPrimaryException.class,
-            ReplicationOperation.RetryOnPrimaryException::new,
-            117,
-            UNKNOWN_VERSION_ADDED
-        ),
-        OPENSEARCH_TIMEOUT_EXCEPTION(
-            org.opensearch.OpenSearchTimeoutException.class,
-            org.opensearch.OpenSearchTimeoutException::new,
-            118,
-            UNKNOWN_VERSION_ADDED
-        ),
-        QUERY_PHASE_EXECUTION_EXCEPTION(
-            org.opensearch.search.query.QueryPhaseExecutionException.class,
-            org.opensearch.search.query.QueryPhaseExecutionException::new,
-            119,
-            UNKNOWN_VERSION_ADDED
-        ),
-        REPOSITORY_VERIFICATION_EXCEPTION(
-            org.opensearch.repositories.RepositoryVerificationException.class,
-            org.opensearch.repositories.RepositoryVerificationException::new,
-            120,
-            UNKNOWN_VERSION_ADDED
-        ),
-        INVALID_AGGREGATION_PATH_EXCEPTION(
-            org.opensearch.search.aggregations.InvalidAggregationPathException.class,
-            org.opensearch.search.aggregations.InvalidAggregationPathException::new,
-            121,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 123 used to be IndexAlreadyExistsException and was renamed
-        RESOURCE_ALREADY_EXISTS_EXCEPTION(
-            ResourceAlreadyExistsException.class,
-            ResourceAlreadyExistsException::new,
-            123,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 124 used to be Script.ScriptParseException
-        HTTP_REQUEST_ON_TRANSPORT_EXCEPTION(
-            TcpTransport.HttpRequestOnTransportException.class,
-            TcpTransport.HttpRequestOnTransportException::new,
-            125,
-            UNKNOWN_VERSION_ADDED
-        ),
-        MAPPER_PARSING_EXCEPTION(
-            org.opensearch.index.mapper.MapperParsingException.class,
-            org.opensearch.index.mapper.MapperParsingException::new,
-            126,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 127 used to be org.opensearch.search.SearchContextException
-        SEARCH_SOURCE_BUILDER_EXCEPTION(
-            org.opensearch.search.builder.SearchSourceBuilderException.class,
-            org.opensearch.search.builder.SearchSourceBuilderException::new,
-            128,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 129 was EngineClosedException
-        NO_SHARD_AVAILABLE_ACTION_EXCEPTION(
-            org.opensearch.action.NoShardAvailableActionException.class,
-            org.opensearch.action.NoShardAvailableActionException::new,
-            130,
-            UNKNOWN_VERSION_ADDED
-        ),
-        UNAVAILABLE_SHARDS_EXCEPTION(
-            org.opensearch.action.UnavailableShardsException.class,
-            org.opensearch.action.UnavailableShardsException::new,
-            131,
-            UNKNOWN_VERSION_ADDED
-        ),
-        FLUSH_FAILED_ENGINE_EXCEPTION(
-            org.opensearch.index.engine.FlushFailedEngineException.class,
-            org.opensearch.index.engine.FlushFailedEngineException::new,
-            132,
-            UNKNOWN_VERSION_ADDED
-        ),
-        CIRCUIT_BREAKING_EXCEPTION(
-            org.opensearch.common.breaker.CircuitBreakingException.class,
-            org.opensearch.common.breaker.CircuitBreakingException::new,
-            133,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NODE_NOT_CONNECTED_EXCEPTION(
-            org.opensearch.transport.NodeNotConnectedException.class,
-            org.opensearch.transport.NodeNotConnectedException::new,
-            134,
-            UNKNOWN_VERSION_ADDED
-        ),
-        STRICT_DYNAMIC_MAPPING_EXCEPTION(
-            org.opensearch.index.mapper.StrictDynamicMappingException.class,
-            org.opensearch.index.mapper.StrictDynamicMappingException::new,
-            135,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RETRY_ON_REPLICA_EXCEPTION(
-            org.opensearch.action.support.replication.TransportReplicationAction.RetryOnReplicaException.class,
-            org.opensearch.action.support.replication.TransportReplicationAction.RetryOnReplicaException::new,
-            136,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TYPE_MISSING_EXCEPTION(
-            org.opensearch.indices.TypeMissingException.class,
-            org.opensearch.indices.TypeMissingException::new,
-            137,
-            UNKNOWN_VERSION_ADDED
-        ),
-        FAILED_TO_COMMIT_CLUSTER_STATE_EXCEPTION(
-            org.opensearch.cluster.coordination.FailedToCommitClusterStateException.class,
-            org.opensearch.cluster.coordination.FailedToCommitClusterStateException::new,
-            140,
-            UNKNOWN_VERSION_ADDED
-        ),
-        QUERY_SHARD_EXCEPTION(
-            org.opensearch.index.query.QueryShardException.class,
-            org.opensearch.index.query.QueryShardException::new,
-            141,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NO_LONGER_PRIMARY_SHARD_EXCEPTION(
-            ShardStateAction.NoLongerPrimaryShardException.class,
-            ShardStateAction.NoLongerPrimaryShardException::new,
-            142,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SCRIPT_EXCEPTION(
-            org.opensearch.script.ScriptException.class,
-            org.opensearch.script.ScriptException::new,
-            143,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NOT_MASTER_EXCEPTION(
-            org.opensearch.cluster.NotMasterException.class,
-            org.opensearch.cluster.NotMasterException::new,
-            144,
-            UNKNOWN_VERSION_ADDED
-        ),
-        STATUS_EXCEPTION(
-            org.opensearch.OpenSearchStatusException.class,
-            org.opensearch.OpenSearchStatusException::new,
-            145,
-            UNKNOWN_VERSION_ADDED
-        ),
-        TASK_CANCELLED_EXCEPTION(
-            org.opensearch.tasks.TaskCancelledException.class,
-            org.opensearch.tasks.TaskCancelledException::new,
-            146,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SHARD_LOCK_OBTAIN_FAILED_EXCEPTION(
-            org.opensearch.env.ShardLockObtainFailedException.class,
-            org.opensearch.env.ShardLockObtainFailedException::new,
-            147,
-            UNKNOWN_VERSION_ADDED
-        ),
-        // 148 was UnknownNamedObjectException
-        TOO_MANY_BUCKETS_EXCEPTION(
-            MultiBucketConsumerService.TooManyBucketsException.class,
-            MultiBucketConsumerService.TooManyBucketsException::new,
-            149,
-            UNKNOWN_VERSION_ADDED
-        ),
-        COORDINATION_STATE_REJECTED_EXCEPTION(
-            org.opensearch.cluster.coordination.CoordinationStateRejectedException.class,
-            org.opensearch.cluster.coordination.CoordinationStateRejectedException::new,
-            150,
-            LegacyESVersion.V_7_0_0
-        ),
-        SNAPSHOT_IN_PROGRESS_EXCEPTION(
-            org.opensearch.snapshots.SnapshotInProgressException.class,
-            org.opensearch.snapshots.SnapshotInProgressException::new,
-            151,
-            UNKNOWN_VERSION_ADDED
-        ),
-        NO_SUCH_REMOTE_CLUSTER_EXCEPTION(
-            org.opensearch.transport.NoSuchRemoteClusterException.class,
-            org.opensearch.transport.NoSuchRemoteClusterException::new,
-            152,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RETENTION_LEASE_ALREADY_EXISTS_EXCEPTION(
-            org.opensearch.index.seqno.RetentionLeaseAlreadyExistsException.class,
-            org.opensearch.index.seqno.RetentionLeaseAlreadyExistsException::new,
-            153,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RETENTION_LEASE_NOT_FOUND_EXCEPTION(
-            org.opensearch.index.seqno.RetentionLeaseNotFoundException.class,
-            org.opensearch.index.seqno.RetentionLeaseNotFoundException::new,
-            154,
-            UNKNOWN_VERSION_ADDED
-        ),
-        SHARD_NOT_IN_PRIMARY_MODE_EXCEPTION(
-            org.opensearch.index.shard.ShardNotInPrimaryModeException.class,
-            org.opensearch.index.shard.ShardNotInPrimaryModeException::new,
-            155,
-            UNKNOWN_VERSION_ADDED
-        ),
-        RETENTION_LEASE_INVALID_RETAINING_SEQUENCE_NUMBER_EXCEPTION(
-            org.opensearch.index.seqno.RetentionLeaseInvalidRetainingSeqNoException.class,
-            org.opensearch.index.seqno.RetentionLeaseInvalidRetainingSeqNoException::new,
-            156,
-            LegacyESVersion.V_7_5_0
-        ),
-        INGEST_PROCESSOR_EXCEPTION(
-            org.opensearch.ingest.IngestProcessorException.class,
-            org.opensearch.ingest.IngestProcessorException::new,
-            157,
-            LegacyESVersion.V_7_5_0
-        ),
-        PEER_RECOVERY_NOT_FOUND_EXCEPTION(
-            org.opensearch.indices.recovery.PeerRecoveryNotFound.class,
-            org.opensearch.indices.recovery.PeerRecoveryNotFound::new,
-            158,
-            LegacyESVersion.V_7_9_0
-        ),
-        NODE_HEALTH_CHECK_FAILURE_EXCEPTION(
-            org.opensearch.cluster.coordination.NodeHealthCheckFailureException.class,
-            org.opensearch.cluster.coordination.NodeHealthCheckFailureException::new,
-            159,
-            LegacyESVersion.V_7_9_0
-        ),
-        NO_SEED_NODE_LEFT_EXCEPTION(
-            org.opensearch.transport.NoSeedNodeLeftException.class,
-            org.opensearch.transport.NoSeedNodeLeftException::new,
-            160,
-            LegacyESVersion.V_7_10_0
-        );
-
-        final Class<? extends OpenSearchException> exceptionClass;
-        final CheckedFunction<StreamInput, ? extends OpenSearchException, IOException> constructor;
-        final int id;
-        final Version versionAdded;
-
-        <E extends OpenSearchException> OpenSearchExceptionHandle(
-            Class<E> exceptionClass,
-            CheckedFunction<StreamInput, E, IOException> constructor,
-            int id,
-            Version versionAdded
-        ) {
-            // We need the exceptionClass because you can't dig it out of the constructor reliably.
-            this.exceptionClass = exceptionClass;
-            this.constructor = constructor;
-            this.versionAdded = versionAdded;
-            this.id = id;
-        }
-    }
-
-    /**
-     * Returns an array of all registered handle IDs. These are the IDs for every registered
-     * exception.
-     *
-     * @return an array of all registered handle IDs
-     */
-    static int[] ids() {
-        return Arrays.stream(OpenSearchExceptionHandle.values()).mapToInt(h -> h.id).toArray();
-    }
-
-    /**
-     * Returns an array of all registered pairs of handle IDs and exception classes. These pairs are
-     * provided for every registered exception.
-     *
-     * @return an array of all registered pairs of handle IDs and exception classes
-     */
-    static Tuple<Integer, Class<? extends OpenSearchException>>[] classes() {
-        @SuppressWarnings("unchecked")
-        final Tuple<Integer, Class<? extends OpenSearchException>>[] ts = Arrays.stream(OpenSearchExceptionHandle.values())
-            .map(h -> Tuple.tuple(h.id, h.exceptionClass))
-            .toArray(Tuple[]::new);
-        return ts;
-    }
-
-    static {
-        ID_TO_SUPPLIER = unmodifiableMap(
-            Arrays.stream(OpenSearchExceptionHandle.values()).collect(Collectors.toMap(e -> e.id, e -> e.constructor))
-        );
-        CLASS_TO_OPENSEARCH_EXCEPTION_HANDLE = unmodifiableMap(
-            Arrays.stream(OpenSearchExceptionHandle.values()).collect(Collectors.toMap(e -> e.exceptionClass, e -> e))
-        );
-    }
-
-    public Index getIndex() {
-        List<String> index = getMetadata(INDEX_METADATA_KEY);
-        if (index != null && index.isEmpty() == false) {
-            List<String> index_uuid = getMetadata(INDEX_METADATA_KEY_UUID);
-            return new Index(index.get(0), index_uuid.get(0));
-        }
-
-        return null;
-    }
-
-    public ShardId getShardId() {
-        List<String> shard = getMetadata(SHARD_METADATA_KEY);
-        if (shard != null && shard.isEmpty() == false) {
-            return new ShardId(getIndex(), Integer.parseInt(shard.get(0)));
-        }
-        return null;
-    }
-
-    public void setIndex(Index index) {
-        if (index != null) {
-            addMetadata(INDEX_METADATA_KEY, index.getName());
-            addMetadata(INDEX_METADATA_KEY_UUID, index.getUUID());
-        }
-    }
-
-    public void setIndex(String index) {
-        if (index != null) {
-            setIndex(new Index(index, INDEX_UUID_NA_VALUE));
-        }
-    }
-
-    public void setShard(ShardId shardId) {
-        if (shardId != null) {
-            setIndex(shardId.getIndex());
-            addMetadata(SHARD_METADATA_KEY, Integer.toString(shardId.id()));
-        }
-    }
-
-    public void setResources(String type, String... id) {
-        assert type != null;
-        addMetadata(RESOURCE_METADATA_ID_KEY, id);
-        addMetadata(RESOURCE_METADATA_TYPE_KEY, type);
-    }
-
-    public List<String> getResourceId() {
-        return getMetadata(RESOURCE_METADATA_ID_KEY);
-    }
-
-    public String getResourceType() {
-        List<String> header = getMetadata(RESOURCE_METADATA_TYPE_KEY);
-        if (header != null && header.isEmpty() == false) {
-            assert header.size() == 1;
-            return header.get(0);
-        }
-        return null;
-    }
-
-    // lower cases and adds underscores to transitions in a name
-    private static String toUnderscoreCase(String value) {
-        StringBuilder sb = new StringBuilder();
-        boolean changed = false;
-        for (int i = 0; i < value.length(); i++) {
-            char c = value.charAt(i);
-            if (Character.isUpperCase(c)) {
-                if (!changed) {
-                    // copy it over here
-                    for (int j = 0; j < i; j++) {
-                        sb.append(value.charAt(j));
-                    }
-                    changed = true;
-                    if (i == 0) {
-                        sb.append(Character.toLowerCase(c));
-                    } else {
-                        sb.append('_');
-                        sb.append(Character.toLowerCase(c));
-                    }
-                } else {
-                    sb.append('_');
-                    sb.append(Character.toLowerCase(c));
-                }
-            } else {
-                if (changed) {
-                    sb.append(c);
-                }
-            }
-        }
-        if (!changed) {
-            return value;
-        }
-        return sb.toString();
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/OpenSearchGenerationException.java b/server/src/main/java/org/opensearch/OpenSearchGenerationException.java
index 1f112aaf5a6e6..50b021d41123f 100644
--- a/server/src/main/java/org/opensearch/OpenSearchGenerationException.java
+++ b/server/src/main/java/org/opensearch/OpenSearchGenerationException.java
@@ -32,14 +32,14 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A generic exception indicating failure to generate.
  *
- *
+ * @opensearch.internal
  */
 public class OpenSearchGenerationException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/OpenSearchSecurityException.java b/server/src/main/java/org/opensearch/OpenSearchSecurityException.java
index 35edb058605a7..f3b2022f03e38 100644
--- a/server/src/main/java/org/opensearch/OpenSearchSecurityException.java
+++ b/server/src/main/java/org/opensearch/OpenSearchSecurityException.java
@@ -31,13 +31,15 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Generic security exception
+ *
+ * @opensearch.internal
  */
 public class OpenSearchSecurityException extends OpenSearchStatusException {
     /**
diff --git a/server/src/main/java/org/opensearch/OpenSearchServerException.java b/server/src/main/java/org/opensearch/OpenSearchServerException.java
new file mode 100644
index 0000000000000..10c5beb46092f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/OpenSearchServerException.java
@@ -0,0 +1,1191 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch;
+
+import org.opensearch.crypto.CryptoRegistryException;
+
+import static org.opensearch.OpenSearchException.OpenSearchExceptionHandle;
+import static org.opensearch.OpenSearchException.OpenSearchExceptionHandleRegistry.registerExceptionHandle;
+import static org.opensearch.OpenSearchException.UNKNOWN_VERSION_ADDED;
+import static org.opensearch.Version.V_2_10_0;
+import static org.opensearch.Version.V_2_1_0;
+import static org.opensearch.Version.V_2_3_0;
+import static org.opensearch.Version.V_2_4_0;
+import static org.opensearch.Version.V_2_5_0;
+import static org.opensearch.Version.V_2_6_0;
+import static org.opensearch.Version.V_2_7_0;
+
+/**
+ * Utility class to register server exceptions
+ *
+ * @opensearch.internal
+ */
+public final class OpenSearchServerException {
+
+    private OpenSearchServerException() {
+        // no ctor:
+    }
+
+    /**
+     * Setting a higher base exception id to avoid conflicts.
+     */
+    private static final int CUSTOM_ELASTICSEARCH_EXCEPTIONS_BASE_ID = 10000;
+
+    public static void registerExceptions() {
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.dfs.DfsPhaseExecutionException.class,
+                org.opensearch.search.dfs.DfsPhaseExecutionException::new,
+                1,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.common.util.CancellableThreads.ExecutionCancelledException.class,
+                org.opensearch.common.util.CancellableThreads.ExecutionCancelledException::new,
+                2,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.discovery.ClusterManagerNotDiscoveredException.class,
+                org.opensearch.discovery.ClusterManagerNotDiscoveredException::new,
+                3,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchSecurityException.class,
+                org.opensearch.OpenSearchSecurityException::new,
+                4,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.snapshots.IndexShardRestoreException.class,
+                org.opensearch.index.snapshots.IndexShardRestoreException::new,
+                5,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.IndexClosedException.class,
+                org.opensearch.indices.IndexClosedException::new,
+                6,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.http.BindHttpException.class,
+                org.opensearch.http.BindHttpException::new,
+                7,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.search.ReduceSearchPhaseException.class,
+                org.opensearch.action.search.ReduceSearchPhaseException::new,
+                8,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.node.NodeClosedException.class,
+                org.opensearch.node.NodeClosedException::new,
+                9,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.SnapshotFailedEngineException.class,
+                org.opensearch.index.engine.SnapshotFailedEngineException::new,
+                10,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.ShardNotFoundException.class,
+                org.opensearch.index.shard.ShardNotFoundException::new,
+                11,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.ConnectTransportException.class,
+                org.opensearch.transport.ConnectTransportException::new,
+                12,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NotSerializableTransportException.class,
+                org.opensearch.transport.NotSerializableTransportException::new,
+                13,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.ResponseHandlerFailureTransportException.class,
+                org.opensearch.transport.ResponseHandlerFailureTransportException::new,
+                14,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.IndexCreationException.class,
+                org.opensearch.indices.IndexCreationException::new,
+                15,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.IndexNotFoundException.class,
+                org.opensearch.index.IndexNotFoundException::new,
+                16,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.routing.IllegalShardRoutingStateException.class,
+                org.opensearch.cluster.routing.IllegalShardRoutingStateException::new,
+                17,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException.class,
+                org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException::new,
+                18,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.ResourceNotFoundException.class,
+                org.opensearch.ResourceNotFoundException::new,
+                19,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.ActionTransportException.class,
+                org.opensearch.transport.ActionTransportException::new,
+                20,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchGenerationException.class,
+                org.opensearch.OpenSearchGenerationException::new,
+                21,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 22 was CreateFailedEngineException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardStartedException.class,
+                org.opensearch.index.shard.IndexShardStartedException::new,
+                23,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.SearchContextMissingException.class,
+                org.opensearch.search.SearchContextMissingException::new,
+                24,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.script.GeneralScriptException.class,
+                org.opensearch.script.GeneralScriptException::new,
+                25,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 26 was BatchOperationException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotCreationException.class,
+                org.opensearch.snapshots.SnapshotCreationException::new,
+                27,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 28 was DeleteFailedEngineException, deprecated in 6.0, removed in 7.0
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.DocumentMissingException.class,
+                org.opensearch.index.engine.DocumentMissingException::new,
+                29,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotException.class,
+                org.opensearch.snapshots.SnapshotException::new,
+                30,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.InvalidAliasNameException.class,
+                org.opensearch.indices.InvalidAliasNameException::new,
+                31,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.InvalidIndexNameException.class,
+                org.opensearch.indices.InvalidIndexNameException::new,
+                32,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.IndexPrimaryShardNotAllocatedException.class,
+                org.opensearch.indices.IndexPrimaryShardNotAllocatedException::new,
+                33,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.TransportException.class,
+                org.opensearch.transport.TransportException::new,
+                34,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.SearchException.class,
+                org.opensearch.search.SearchException::new,
+                36,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.mapper.MapperException.class,
+                org.opensearch.index.mapper.MapperException::new,
+                37,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.InvalidTypeNameException.class,
+                org.opensearch.indices.InvalidTypeNameException::new,
+                38,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotRestoreException.class,
+                org.opensearch.snapshots.SnapshotRestoreException::new,
+                39,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardClosedException.class,
+                org.opensearch.index.shard.IndexShardClosedException::new,
+                41,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.recovery.RecoverFilesRecoveryException.class,
+                org.opensearch.indices.recovery.RecoverFilesRecoveryException::new,
+                42,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.translog.TruncatedTranslogException.class,
+                org.opensearch.index.translog.TruncatedTranslogException::new,
+                43,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.recovery.RecoveryFailedException.class,
+                org.opensearch.indices.recovery.RecoveryFailedException::new,
+                44,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardRelocatedException.class,
+                org.opensearch.index.shard.IndexShardRelocatedException::new,
+                45,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NodeShouldNotConnectException.class,
+                org.opensearch.transport.NodeShouldNotConnectException::new,
+                46,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 47 used to be for IndexTemplateAlreadyExistsException which was deprecated in 5.1 removed in 6.0
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.translog.TranslogCorruptedException.class,
+                org.opensearch.index.translog.TranslogCorruptedException::new,
+                48,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.block.ClusterBlockException.class,
+                org.opensearch.cluster.block.ClusterBlockException::new,
+                49,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.fetch.FetchPhaseExecutionException.class,
+                org.opensearch.search.fetch.FetchPhaseExecutionException::new,
+                50,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 51 used to be for IndexShardAlreadyExistsException which was deprecated in 5.1 removed in 6.0
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.VersionConflictEngineException.class,
+                org.opensearch.index.engine.VersionConflictEngineException::new,
+                52,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.EngineException.class,
+                org.opensearch.index.engine.EngineException::new,
+                53,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 54 was DocumentAlreadyExistsException, which is superseded by VersionConflictEngineException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.NoSuchNodeException.class,
+                org.opensearch.action.NoSuchNodeException::new,
+                55,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.common.settings.SettingsException.class,
+                org.opensearch.common.settings.SettingsException::new,
+                56,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.IndexTemplateMissingException.class,
+                org.opensearch.indices.IndexTemplateMissingException::new,
+                57,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.SendRequestTransportException.class,
+                org.opensearch.transport.SendRequestTransportException::new,
+                58,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 59 used to be OpenSearchRejectedExecutionException
+        // 60 used to be for EarlyTerminationException
+        // 61 used to be for RoutingValidationException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.AliasFilterParsingException.class,
+                org.opensearch.indices.AliasFilterParsingException::new,
+                63,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 64 was DeleteByQueryFailedEngineException, which was removed in 5.0
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.gateway.GatewayException.class,
+                org.opensearch.gateway.GatewayException::new,
+                65,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardNotRecoveringException.class,
+                org.opensearch.index.shard.IndexShardNotRecoveringException::new,
+                66,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.http.HttpException.class,
+                org.opensearch.http.HttpException::new,
+                67,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchException.class,
+                org.opensearch.OpenSearchException::new,
+                68,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotMissingException.class,
+                org.opensearch.snapshots.SnapshotMissingException::new,
+                69,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.PrimaryMissingActionException.class,
+                org.opensearch.action.PrimaryMissingActionException::new,
+                70,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.SearchParseException.class,
+                org.opensearch.search.SearchParseException::new,
+                72,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.FailedNodeException.class,
+                org.opensearch.action.FailedNodeException::new,
+                71,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.ConcurrentSnapshotExecutionException.class,
+                org.opensearch.snapshots.ConcurrentSnapshotExecutionException::new,
+                73,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.common.blobstore.BlobStoreException.class,
+                org.opensearch.common.blobstore.BlobStoreException::new,
+                74,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.IncompatibleClusterStateVersionException.class,
+                org.opensearch.cluster.IncompatibleClusterStateVersionException::new,
+                75,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.RecoveryEngineException.class,
+                org.opensearch.index.engine.RecoveryEngineException::new,
+                76,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.common.util.concurrent.UncategorizedExecutionException.class,
+                org.opensearch.common.util.concurrent.UncategorizedExecutionException::new,
+                77,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.TimestampParsingException.class,
+                org.opensearch.action.TimestampParsingException::new,
+                78,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.RoutingMissingException.class,
+                org.opensearch.action.RoutingMissingException::new,
+                79,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 80 was IndexFailedEngineException, deprecated in 6.0, removed in 7.0
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.snapshots.IndexShardRestoreFailedException.class,
+                org.opensearch.index.snapshots.IndexShardRestoreFailedException::new,
+                81,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.repositories.RepositoryException.class,
+                org.opensearch.repositories.RepositoryException::new,
+                82,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.ReceiveTimeoutTransportException.class,
+                org.opensearch.transport.ReceiveTimeoutTransportException::new,
+                83,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NodeDisconnectedException.class,
+                org.opensearch.transport.NodeDisconnectedException::new,
+                84,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 85 used to be for AlreadyExpiredException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.aggregations.AggregationExecutionException.class,
+                org.opensearch.search.aggregations.AggregationExecutionException::new,
+                86,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 87 used to be for MergeMappingException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.InvalidIndexTemplateException.class,
+                org.opensearch.indices.InvalidIndexTemplateException::new,
+                88,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.RefreshFailedEngineException.class,
+                org.opensearch.index.engine.RefreshFailedEngineException::new,
+                90,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.aggregations.AggregationInitializationException.class,
+                org.opensearch.search.aggregations.AggregationInitializationException::new,
+                91,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.recovery.DelayRecoveryException.class,
+                org.opensearch.indices.recovery.DelayRecoveryException::new,
+                92,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 93 used to be for IndexWarmerMissingException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.client.transport.NoNodeAvailableException.class,
+                org.opensearch.client.transport.NoNodeAvailableException::new,
+                94,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.InvalidSnapshotNameException.class,
+                org.opensearch.snapshots.InvalidSnapshotNameException::new,
+                96,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IllegalIndexShardStateException.class,
+                org.opensearch.index.shard.IllegalIndexShardStateException::new,
+                97,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.core.index.snapshots.IndexShardSnapshotException.class,
+                org.opensearch.core.index.snapshots.IndexShardSnapshotException::new,
+                98,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardNotStartedException.class,
+                org.opensearch.index.shard.IndexShardNotStartedException::new,
+                99,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.search.SearchPhaseExecutionException.class,
+                org.opensearch.action.search.SearchPhaseExecutionException::new,
+                100,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.ActionNotFoundTransportException.class,
+                org.opensearch.transport.ActionNotFoundTransportException::new,
+                101,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.TransportSerializationException.class,
+                org.opensearch.transport.TransportSerializationException::new,
+                102,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.RemoteTransportException.class,
+                org.opensearch.transport.RemoteTransportException::new,
+                103,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.EngineCreationFailureException.class,
+                org.opensearch.index.engine.EngineCreationFailureException::new,
+                104,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.routing.RoutingException.class,
+                org.opensearch.cluster.routing.RoutingException::new,
+                105,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardRecoveryException.class,
+                org.opensearch.index.shard.IndexShardRecoveryException::new,
+                106,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.repositories.RepositoryMissingException.class,
+                org.opensearch.repositories.RepositoryMissingException::new,
+                107,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.DocumentSourceMissingException.class,
+                org.opensearch.index.engine.DocumentSourceMissingException::new,
+                109,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 110 used to be FlushNotAllowedEngineException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.common.settings.NoClassSettingsException.class,
+                org.opensearch.common.settings.NoClassSettingsException::new,
+                111,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.BindTransportException.class,
+                org.opensearch.transport.BindTransportException::new,
+                112,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.rest.action.admin.indices.AliasesNotFoundException.class,
+                org.opensearch.rest.action.admin.indices.AliasesNotFoundException::new,
+                113,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.IndexShardRecoveringException.class,
+                org.opensearch.index.shard.IndexShardRecoveringException::new,
+                114,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.translog.TranslogException.class,
+                org.opensearch.index.translog.TranslogException::new,
+                115,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException.class,
+                org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException::new,
+                116,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.support.replication.ReplicationOperation.RetryOnPrimaryException.class,
+                org.opensearch.action.support.replication.ReplicationOperation.RetryOnPrimaryException::new,
+                117,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchTimeoutException.class,
+                org.opensearch.OpenSearchTimeoutException::new,
+                118,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.query.QueryPhaseExecutionException.class,
+                org.opensearch.search.query.QueryPhaseExecutionException::new,
+                119,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.repositories.RepositoryVerificationException.class,
+                org.opensearch.repositories.RepositoryVerificationException::new,
+                120,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.aggregations.InvalidAggregationPathException.class,
+                org.opensearch.search.aggregations.InvalidAggregationPathException::new,
+                121,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 123 used to be IndexAlreadyExistsException and was renamed
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                ResourceAlreadyExistsException.class,
+                ResourceAlreadyExistsException::new,
+                123,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 124 used to be Script.ScriptParseException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.TcpTransport.HttpRequestOnTransportException.class,
+                org.opensearch.transport.TcpTransport.HttpRequestOnTransportException::new,
+                125,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.mapper.MapperParsingException.class,
+                org.opensearch.index.mapper.MapperParsingException::new,
+                126,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 127 used to be org.opensearch.search.SearchContextException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.builder.SearchSourceBuilderException.class,
+                org.opensearch.search.builder.SearchSourceBuilderException::new,
+                128,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 129 was EngineClosedException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.NoShardAvailableActionException.class,
+                org.opensearch.action.NoShardAvailableActionException::new,
+                130,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.UnavailableShardsException.class,
+                org.opensearch.action.UnavailableShardsException::new,
+                131,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.engine.FlushFailedEngineException.class,
+                org.opensearch.index.engine.FlushFailedEngineException::new,
+                132,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NodeNotConnectedException.class,
+                org.opensearch.transport.NodeNotConnectedException::new,
+                134,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.mapper.StrictDynamicMappingException.class,
+                org.opensearch.index.mapper.StrictDynamicMappingException::new,
+                135,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.action.support.replication.TransportReplicationAction.RetryOnReplicaException.class,
+                org.opensearch.action.support.replication.TransportReplicationAction.RetryOnReplicaException::new,
+                136,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.TypeMissingException.class,
+                org.opensearch.indices.TypeMissingException::new,
+                137,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.coordination.FailedToCommitClusterStateException.class,
+                org.opensearch.cluster.coordination.FailedToCommitClusterStateException::new,
+                140,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.query.QueryShardException.class,
+                org.opensearch.index.query.QueryShardException::new,
+                141,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.action.shard.ShardStateAction.NoLongerPrimaryShardException.class,
+                org.opensearch.cluster.action.shard.ShardStateAction.NoLongerPrimaryShardException::new,
+                142,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.script.ScriptException.class,
+                org.opensearch.script.ScriptException::new,
+                143,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.NotClusterManagerException.class,
+                org.opensearch.cluster.NotClusterManagerException::new,
+                144,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.OpenSearchStatusException.class,
+                org.opensearch.OpenSearchStatusException::new,
+                145,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.env.ShardLockObtainFailedException.class,
+                org.opensearch.env.ShardLockObtainFailedException::new,
+                147,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        // 148 was UnknownNamedObjectException
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.aggregations.MultiBucketConsumerService.TooManyBucketsException.class,
+                org.opensearch.search.aggregations.MultiBucketConsumerService.TooManyBucketsException::new,
+                149,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.coordination.CoordinationStateRejectedException.class,
+                org.opensearch.cluster.coordination.CoordinationStateRejectedException::new,
+                150,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotInProgressException.class,
+                org.opensearch.snapshots.SnapshotInProgressException::new,
+                151,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NoSuchRemoteClusterException.class,
+                org.opensearch.transport.NoSuchRemoteClusterException::new,
+                152,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.seqno.RetentionLeaseAlreadyExistsException.class,
+                org.opensearch.index.seqno.RetentionLeaseAlreadyExistsException::new,
+                153,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.seqno.RetentionLeaseNotFoundException.class,
+                org.opensearch.index.seqno.RetentionLeaseNotFoundException::new,
+                154,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.ShardNotInPrimaryModeException.class,
+                org.opensearch.index.shard.ShardNotInPrimaryModeException::new,
+                155,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.seqno.RetentionLeaseInvalidRetainingSeqNoException.class,
+                org.opensearch.index.seqno.RetentionLeaseInvalidRetainingSeqNoException::new,
+                156,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.ingest.IngestProcessorException.class,
+                org.opensearch.ingest.IngestProcessorException::new,
+                157,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.recovery.PeerRecoveryNotFound.class,
+                org.opensearch.indices.recovery.PeerRecoveryNotFound::new,
+                158,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.coordination.NodeHealthCheckFailureException.class,
+                org.opensearch.cluster.coordination.NodeHealthCheckFailureException::new,
+                159,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.transport.NoSeedNodeLeftException.class,
+                org.opensearch.transport.NoSeedNodeLeftException::new,
+                160,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.indices.replication.common.ReplicationFailedException.class,
+                org.opensearch.indices.replication.common.ReplicationFailedException::new,
+                161,
+                V_2_1_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.index.shard.PrimaryShardClosedException.class,
+                org.opensearch.index.shard.PrimaryShardClosedException::new,
+                162,
+                V_2_3_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.decommission.DecommissioningFailedException.class,
+                org.opensearch.cluster.decommission.DecommissioningFailedException::new,
+                163,
+                V_2_4_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.decommission.NodeDecommissionedException.class,
+                org.opensearch.cluster.decommission.NodeDecommissionedException::new,
+                164,
+                V_2_4_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.service.ClusterManagerThrottlingException.class,
+                org.opensearch.cluster.service.ClusterManagerThrottlingException::new,
+                165,
+                Version.V_2_5_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.snapshots.SnapshotInUseDeletionException.class,
+                org.opensearch.snapshots.SnapshotInUseDeletionException::new,
+                166,
+                UNKNOWN_VERSION_ADDED
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.routing.UnsupportedWeightedRoutingStateException.class,
+                org.opensearch.cluster.routing.UnsupportedWeightedRoutingStateException::new,
+                167,
+                V_2_5_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.routing.PreferenceBasedSearchNotAllowedException.class,
+                org.opensearch.cluster.routing.PreferenceBasedSearchNotAllowedException::new,
+                168,
+                V_2_6_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.routing.NodeWeighedAwayException.class,
+                org.opensearch.cluster.routing.NodeWeighedAwayException::new,
+                169,
+                V_2_6_0
+            )
+        );
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.search.pipeline.SearchPipelineProcessingException.class,
+                org.opensearch.search.pipeline.SearchPipelineProcessingException::new,
+                170,
+                V_2_7_0
+            )
+        );
+        registerExceptionHandle(new OpenSearchExceptionHandle(CryptoRegistryException.class, CryptoRegistryException::new, 171, V_2_10_0));
+        registerExceptionHandle(
+            new OpenSearchExceptionHandle(
+                org.opensearch.cluster.block.IndexCreateBlockException.class,
+                org.opensearch.cluster.block.IndexCreateBlockException::new,
+                CUSTOM_ELASTICSEARCH_EXCEPTIONS_BASE_ID + 1,
+                V_2_6_0
+            )
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/OpenSearchStatusException.java b/server/src/main/java/org/opensearch/OpenSearchStatusException.java
index 274eac8f8b2ad..8061057465498 100644
--- a/server/src/main/java/org/opensearch/OpenSearchStatusException.java
+++ b/server/src/main/java/org/opensearch/OpenSearchStatusException.java
@@ -32,15 +32,17 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Exception who's {@link RestStatus} is arbitrary rather than derived. Used, for example, by reindex-from-remote to wrap remote exceptions
  * that contain a status.
+ *
+ * @opensearch.internal
  */
 public class OpenSearchStatusException extends OpenSearchException {
     private final RestStatus status;
diff --git a/server/src/main/java/org/opensearch/OpenSearchTimeoutException.java b/server/src/main/java/org/opensearch/OpenSearchTimeoutException.java
index 6b20e145e500b..3b1d7086d0584 100644
--- a/server/src/main/java/org/opensearch/OpenSearchTimeoutException.java
+++ b/server/src/main/java/org/opensearch/OpenSearchTimeoutException.java
@@ -32,14 +32,14 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * The same as {@link java.util.concurrent.TimeoutException} simply a runtime one.
  *
- *
+ * @opensearch.internal
  */
 public class OpenSearchTimeoutException extends OpenSearchException {
     public OpenSearchTimeoutException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/ResourceAlreadyExistsException.java b/server/src/main/java/org/opensearch/ResourceAlreadyExistsException.java
index e6b5177538fa9..9566244062626 100644
--- a/server/src/main/java/org/opensearch/ResourceAlreadyExistsException.java
+++ b/server/src/main/java/org/opensearch/ResourceAlreadyExistsException.java
@@ -32,12 +32,17 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception when Resources already exists
+ *
+ * @opensearch.internal
+ */
 public class ResourceAlreadyExistsException extends OpenSearchException {
 
     public ResourceAlreadyExistsException(Index index) {
diff --git a/server/src/main/java/org/opensearch/ResourceNotFoundException.java b/server/src/main/java/org/opensearch/ResourceNotFoundException.java
index 373493aeb53b1..0a89fa3667542 100644
--- a/server/src/main/java/org/opensearch/ResourceNotFoundException.java
+++ b/server/src/main/java/org/opensearch/ResourceNotFoundException.java
@@ -31,13 +31,15 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Generic ResourceNotFoundException corresponding to the {@link RestStatus#NOT_FOUND} status code
+ *
+ * @opensearch.internal
  */
 public class ResourceNotFoundException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/SpecialPermission.java b/server/src/main/java/org/opensearch/SpecialPermission.java
index 00ae1528d4ef2..8a694d4543f32 100644
--- a/server/src/main/java/org/opensearch/SpecialPermission.java
+++ b/server/src/main/java/org/opensearch/SpecialPermission.java
@@ -68,6 +68,8 @@
  *    ...
  *   );
  * </code></pre>
+ *
+ * @opensearch.internal
  */
 public final class SpecialPermission extends BasicPermission {
 
diff --git a/server/src/main/java/org/opensearch/action/ActionListenerResponseHandler.java b/server/src/main/java/org/opensearch/action/ActionListenerResponseHandler.java
index 83ac650bf48af..1ed774b8f8f9a 100644
--- a/server/src/main/java/org/opensearch/action/ActionListenerResponseHandler.java
+++ b/server/src/main/java/org/opensearch/action/ActionListenerResponseHandler.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.action;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.transport.TransportResponseHandler;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -45,6 +46,8 @@
 /**
  * A simple base class for action response listeners, defaulting to using the SAME executor (as its
  * very common on response handlers).
+ *
+ * @opensearch.internal
  */
 public class ActionListenerResponseHandler<Response extends TransportResponse> implements TransportResponseHandler<Response> {
 
diff --git a/server/src/main/java/org/opensearch/action/ActionModule.java b/server/src/main/java/org/opensearch/action/ActionModule.java
index 8e31aa23d88cf..7b0b725c88f64 100644
--- a/server/src/main/java/org/opensearch/action/ActionModule.java
+++ b/server/src/main/java/org/opensearch/action/ActionModule.java
@@ -40,6 +40,12 @@
 import org.opensearch.action.admin.cluster.configuration.ClearVotingConfigExclusionsAction;
 import org.opensearch.action.admin.cluster.configuration.TransportAddVotingConfigExclusionsAction;
 import org.opensearch.action.admin.cluster.configuration.TransportClearVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.TransportDeleteDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.TransportGetDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.TransportDecommissionAction;
 import org.opensearch.action.admin.cluster.health.ClusterHealthAction;
 import org.opensearch.action.admin.cluster.health.TransportClusterHealthAction;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsAction;
@@ -61,6 +67,10 @@
 import org.opensearch.action.admin.cluster.node.usage.TransportNodesUsageAction;
 import org.opensearch.action.admin.cluster.remote.RemoteInfoAction;
 import org.opensearch.action.admin.cluster.remote.TransportRemoteInfoAction;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreAction;
+import org.opensearch.action.admin.cluster.remotestore.restore.TransportRestoreRemoteStoreAction;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsAction;
+import org.opensearch.action.admin.cluster.remotestore.stats.TransportRemoteStoreStatsAction;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryAction;
 import org.opensearch.action.admin.cluster.repositories.cleanup.TransportCleanupRepositoryAction;
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryAction;
@@ -77,6 +87,12 @@
 import org.opensearch.action.admin.cluster.settings.TransportClusterUpdateSettingsAction;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsAction;
 import org.opensearch.action.admin.cluster.shards.TransportClusterSearchShardsAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.TransportDeleteWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.TransportGetWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterAddWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.TransportAddWeightedRoutingAction;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotAction;
 import org.opensearch.action.admin.cluster.snapshots.clone.TransportCloneSnapshotAction;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotAction;
@@ -108,8 +124,6 @@
 import org.opensearch.action.admin.indices.alias.IndicesAliasesAction;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.TransportIndicesAliasesAction;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistAction;
-import org.opensearch.action.admin.indices.alias.exists.TransportAliasesExistAction;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesAction;
 import org.opensearch.action.admin.indices.alias.get.TransportGetAliasesAction;
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
@@ -137,8 +151,6 @@
 import org.opensearch.action.admin.indices.delete.TransportDeleteIndexAction;
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsAction;
 import org.opensearch.action.admin.indices.exists.indices.TransportIndicesExistsAction;
-import org.opensearch.action.admin.indices.exists.types.TransportTypesExistsAction;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsAction;
 import org.opensearch.action.admin.indices.flush.FlushAction;
 import org.opensearch.action.admin.indices.flush.TransportFlushAction;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeAction;
@@ -163,11 +175,15 @@
 import org.opensearch.action.admin.indices.recovery.TransportRecoveryAction;
 import org.opensearch.action.admin.indices.refresh.RefreshAction;
 import org.opensearch.action.admin.indices.refresh.TransportRefreshAction;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsAction;
+import org.opensearch.action.admin.indices.replication.TransportSegmentReplicationStatsAction;
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction;
 import org.opensearch.action.admin.indices.rollover.RolloverAction;
 import org.opensearch.action.admin.indices.rollover.TransportRolloverAction;
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsAction;
+import org.opensearch.action.admin.indices.segments.PitSegmentsAction;
 import org.opensearch.action.admin.indices.segments.TransportIndicesSegmentsAction;
+import org.opensearch.action.admin.indices.segments.TransportPitSegmentsAction;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsAction;
 import org.opensearch.action.admin.indices.settings.get.TransportGetSettingsAction;
 import org.opensearch.action.admin.indices.settings.put.TransportUpdateSettingsAction;
@@ -236,10 +252,22 @@
 import org.opensearch.action.main.MainAction;
 import org.opensearch.action.main.TransportMainAction;
 import org.opensearch.action.search.ClearScrollAction;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeleteSearchPipelineAction;
+import org.opensearch.action.search.DeleteSearchPipelineTransportAction;
+import org.opensearch.action.search.GetAllPitsAction;
+import org.opensearch.action.search.GetSearchPipelineAction;
+import org.opensearch.action.search.GetSearchPipelineTransportAction;
 import org.opensearch.action.search.MultiSearchAction;
+import org.opensearch.action.search.PutSearchPipelineAction;
+import org.opensearch.action.search.PutSearchPipelineTransportAction;
 import org.opensearch.action.search.SearchAction;
 import org.opensearch.action.search.SearchScrollAction;
 import org.opensearch.action.search.TransportClearScrollAction;
+import org.opensearch.action.search.TransportCreatePitAction;
+import org.opensearch.action.search.TransportDeletePitAction;
+import org.opensearch.action.search.TransportGetAllPitsAction;
 import org.opensearch.action.search.TransportMultiSearchAction;
 import org.opensearch.action.search.TransportSearchAction;
 import org.opensearch.action.search.TransportSearchScrollAction;
@@ -265,15 +293,24 @@
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.extensions.action.ExtensionProxyAction;
+import org.opensearch.extensions.action.ExtensionProxyTransportAction;
+import org.opensearch.extensions.rest.RestInitializeExtensionAction;
+import org.opensearch.extensions.rest.RestSendToExtensionAction;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.index.seqno.RetentionLeaseActions;
 import org.opensearch.indices.SystemIndices;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.persistent.CompletionPersistentTaskAction;
 import org.opensearch.persistent.RemovePersistentTaskAction;
 import org.opensearch.persistent.StartPersistentTaskAction;
 import org.opensearch.persistent.UpdatePersistentTaskStatusAction;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.ActionPlugin.ActionHandler;
+import org.opensearch.rest.NamedRoute;
 import org.opensearch.rest.RestController;
 import org.opensearch.rest.RestHandler;
 import org.opensearch.rest.RestHeaderDefinition;
@@ -285,17 +322,23 @@
 import org.opensearch.rest.action.admin.cluster.RestClearVotingConfigExclusionsAction;
 import org.opensearch.rest.action.admin.cluster.RestCloneSnapshotAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterAllocationExplainAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterDeleteWeightedRoutingAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterGetSettingsAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterGetWeightedRoutingAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterHealthAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterPutWeightedRoutingAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterRerouteAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterSearchShardsAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterStateAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterStatsAction;
 import org.opensearch.rest.action.admin.cluster.RestClusterUpdateSettingsAction;
 import org.opensearch.rest.action.admin.cluster.RestCreateSnapshotAction;
+import org.opensearch.rest.action.admin.cluster.RestDecommissionAction;
+import org.opensearch.rest.action.admin.cluster.RestDeleteDecommissionStateAction;
 import org.opensearch.rest.action.admin.cluster.RestDeleteRepositoryAction;
 import org.opensearch.rest.action.admin.cluster.RestDeleteSnapshotAction;
 import org.opensearch.rest.action.admin.cluster.RestDeleteStoredScriptAction;
+import org.opensearch.rest.action.admin.cluster.RestGetDecommissionStateAction;
 import org.opensearch.rest.action.admin.cluster.RestGetRepositoriesAction;
 import org.opensearch.rest.action.admin.cluster.RestGetScriptContextAction;
 import org.opensearch.rest.action.admin.cluster.RestGetScriptLanguageAction;
@@ -312,6 +355,8 @@
 import org.opensearch.rest.action.admin.cluster.RestPutStoredScriptAction;
 import org.opensearch.rest.action.admin.cluster.RestReloadSecureSettingsAction;
 import org.opensearch.rest.action.admin.cluster.RestRemoteClusterInfoAction;
+import org.opensearch.rest.action.admin.cluster.RestRemoteStoreStatsAction;
+import org.opensearch.rest.action.admin.cluster.RestRestoreRemoteStoreAction;
 import org.opensearch.rest.action.admin.cluster.RestRestoreSnapshotAction;
 import org.opensearch.rest.action.admin.cluster.RestSnapshotsStatusAction;
 import org.opensearch.rest.action.admin.cluster.RestVerifyRepositoryAction;
@@ -369,12 +414,14 @@
 import org.opensearch.rest.action.cat.RestAllocationAction;
 import org.opensearch.rest.action.cat.RestCatAction;
 import org.opensearch.rest.action.cat.RestCatRecoveryAction;
+import org.opensearch.rest.action.cat.RestCatSegmentReplicationAction;
+import org.opensearch.rest.action.cat.RestClusterManagerAction;
 import org.opensearch.rest.action.cat.RestFielddataAction;
 import org.opensearch.rest.action.cat.RestHealthAction;
 import org.opensearch.rest.action.cat.RestIndicesAction;
-import org.opensearch.rest.action.cat.RestMasterAction;
 import org.opensearch.rest.action.cat.RestNodeAttrsAction;
 import org.opensearch.rest.action.cat.RestNodesAction;
+import org.opensearch.rest.action.cat.RestPitSegmentsAction;
 import org.opensearch.rest.action.cat.RestPluginsAction;
 import org.opensearch.rest.action.cat.RestRepositoriesAction;
 import org.opensearch.rest.action.cat.RestSegmentsAction;
@@ -400,8 +447,14 @@
 import org.opensearch.rest.action.ingest.RestSimulatePipelineAction;
 import org.opensearch.rest.action.search.RestClearScrollAction;
 import org.opensearch.rest.action.search.RestCountAction;
+import org.opensearch.rest.action.search.RestCreatePitAction;
+import org.opensearch.rest.action.search.RestDeletePitAction;
+import org.opensearch.rest.action.search.RestDeleteSearchPipelineAction;
 import org.opensearch.rest.action.search.RestExplainAction;
+import org.opensearch.rest.action.search.RestGetAllPitsAction;
+import org.opensearch.rest.action.search.RestGetSearchPipelineAction;
 import org.opensearch.rest.action.search.RestMultiSearchAction;
+import org.opensearch.rest.action.search.RestPutSearchPipelineAction;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.rest.action.search.RestSearchScrollAction;
 import org.opensearch.tasks.Task;
@@ -410,9 +463,12 @@
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentSkipListSet;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 import java.util.function.UnaryOperator;
@@ -420,9 +476,12 @@
 import java.util.stream.Stream;
 
 import static java.util.Collections.unmodifiableMap;
+import static java.util.Objects.requireNonNull;
 
 /**
  * Builds and binds the generic action map, all {@link TransportAction}s, and {@link ActionFilters}.
+ *
+ * @opensearch.internal
  */
 public class ActionModule extends AbstractModule {
 
@@ -434,7 +493,17 @@ public class ActionModule extends AbstractModule {
     private final ClusterSettings clusterSettings;
     private final SettingsFilter settingsFilter;
     private final List<ActionPlugin> actionPlugins;
+    // The unmodifiable map containing OpenSearch and Plugin actions
+    // This is initialized at node bootstrap and contains same-JVM actions
+    // It will be wrapped in the Dynamic Action Registry but otherwise
+    // remains unchanged from its prior purpose, and registered actions
+    // will remain accessible.
     private final Map<String, ActionHandler<?, ?>> actions;
+    // A dynamic action registry which includes the above immutable actions
+    // and also registers dynamic actions which may be unregistered. Usually
+    // associated with remote action execution on extensions, possibly in
+    // a different JVM and possibly on a different server.
+    private final DynamicActionRegistry dynamicActionRegistry;
     private final ActionFilters actionFilters;
     private final AutoCreateIndex autoCreateIndex;
     private final DestructiveOperations destructiveOperations;
@@ -442,6 +511,7 @@ public class ActionModule extends AbstractModule {
     private final RequestValidators<PutMappingRequest> mappingRequestValidators;
     private final RequestValidators<IndicesAliasesRequest> indicesAliasesRequestRequestValidators;
     private final ThreadPool threadPool;
+    private final ExtensionsManager extensionsManager;
 
     public ActionModule(
         Settings settings,
@@ -454,7 +524,9 @@ public ActionModule(
         NodeClient nodeClient,
         CircuitBreakerService circuitBreakerService,
         UsageService usageService,
-        SystemIndices systemIndices
+        SystemIndices systemIndices,
+        IdentityService identityService,
+        ExtensionsManager extensionsManager
     ) {
         this.settings = settings;
         this.indexNameExpressionResolver = indexNameExpressionResolver;
@@ -463,8 +535,10 @@ public ActionModule(
         this.settingsFilter = settingsFilter;
         this.actionPlugins = actionPlugins;
         this.threadPool = threadPool;
+        this.extensionsManager = extensionsManager;
         actions = setupActions(actionPlugins);
         actionFilters = setupActionFilters(actionPlugins);
+        dynamicActionRegistry = new DynamicActionRegistry();
         autoCreateIndex = new AutoCreateIndex(settings, clusterSettings, indexNameExpressionResolver, systemIndices);
         destructiveOperations = new DestructiveOperations(settings, clusterSettings);
         Set<RestHeaderDefinition> headers = Stream.concat(
@@ -489,7 +563,7 @@ public ActionModule(
             actionPlugins.stream().flatMap(p -> p.indicesAliasesRequestValidators().stream()).collect(Collectors.toList())
         );
 
-        restController = new RestController(headers, restWrapper, nodeClient, circuitBreakerService, usageService);
+        restController = new RestController(headers, restWrapper, nodeClient, circuitBreakerService, usageService, identityService);
     }
 
     public Map<String, ActionHandler<?, ?>> getActions() {
@@ -521,6 +595,7 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(NodesInfoAction.INSTANCE, TransportNodesInfoAction.class);
         actions.register(RemoteInfoAction.INSTANCE, TransportRemoteInfoAction.class);
         actions.register(NodesStatsAction.INSTANCE, TransportNodesStatsAction.class);
+        actions.register(RemoteStoreStatsAction.INSTANCE, TransportRemoteStoreStatsAction.class);
         actions.register(NodesUsageAction.INSTANCE, TransportNodesUsageAction.class);
         actions.register(NodesHotThreadsAction.INSTANCE, TransportNodesHotThreadsAction.class);
         actions.register(ListTasksAction.INSTANCE, TransportListTasksAction.class);
@@ -549,6 +624,9 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(RestoreSnapshotAction.INSTANCE, TransportRestoreSnapshotAction.class);
         actions.register(SnapshotsStatusAction.INSTANCE, TransportSnapshotsStatusAction.class);
 
+        actions.register(ClusterAddWeightedRoutingAction.INSTANCE, TransportAddWeightedRoutingAction.class);
+        actions.register(ClusterGetWeightedRoutingAction.INSTANCE, TransportGetWeightedRoutingAction.class);
+        actions.register(ClusterDeleteWeightedRoutingAction.INSTANCE, TransportDeleteWeightedRoutingAction.class);
         actions.register(IndicesStatsAction.INSTANCE, TransportIndicesStatsAction.class);
         actions.register(IndicesSegmentsAction.INSTANCE, TransportIndicesSegmentsAction.class);
         actions.register(IndicesShardStoresAction.INSTANCE, TransportIndicesShardStoresAction.class);
@@ -560,7 +638,6 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(OpenIndexAction.INSTANCE, TransportOpenIndexAction.class);
         actions.register(CloseIndexAction.INSTANCE, TransportCloseIndexAction.class);
         actions.register(IndicesExistsAction.INSTANCE, TransportIndicesExistsAction.class);
-        actions.register(TypesExistsAction.INSTANCE, TransportTypesExistsAction.class);
         actions.register(AddIndexBlockAction.INSTANCE, TransportAddIndexBlockAction.class);
         actions.register(GetMappingsAction.INSTANCE, TransportGetMappingsAction.class);
         actions.register(
@@ -593,7 +670,6 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(UpgradeSettingsAction.INSTANCE, TransportUpgradeSettingsAction.class);
         actions.register(ClearIndicesCacheAction.INSTANCE, TransportClearIndicesCacheAction.class);
         actions.register(GetAliasesAction.INSTANCE, TransportGetAliasesAction.class);
-        actions.register(AliasesExistAction.INSTANCE, TransportAliasesExistAction.class);
         actions.register(GetSettingsAction.INSTANCE, TransportGetSettingsAction.class);
 
         actions.register(IndexAction.INSTANCE, TransportIndexAction.class);
@@ -614,6 +690,7 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(ExplainAction.INSTANCE, TransportExplainAction.class);
         actions.register(ClearScrollAction.INSTANCE, TransportClearScrollAction.class);
         actions.register(RecoveryAction.INSTANCE, TransportRecoveryAction.class);
+        actions.register(SegmentReplicationStatsAction.INSTANCE, TransportSegmentReplicationStatsAction.class);
         actions.register(NodesReloadSecureSettingsAction.INSTANCE, TransportNodesReloadSecureSettingsAction.class);
         actions.register(AutoCreateAction.INSTANCE, AutoCreateAction.TransportAction.class);
 
@@ -661,6 +738,30 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
         actions.register(DeleteDanglingIndexAction.INSTANCE, TransportDeleteDanglingIndexAction.class);
         actions.register(FindDanglingIndexAction.INSTANCE, TransportFindDanglingIndexAction.class);
 
+        // Remote Store
+        actions.register(RestoreRemoteStoreAction.INSTANCE, TransportRestoreRemoteStoreAction.class);
+
+        // point in time actions
+        actions.register(CreatePitAction.INSTANCE, TransportCreatePitAction.class);
+        actions.register(DeletePitAction.INSTANCE, TransportDeletePitAction.class);
+        actions.register(PitSegmentsAction.INSTANCE, TransportPitSegmentsAction.class);
+        actions.register(GetAllPitsAction.INSTANCE, TransportGetAllPitsAction.class);
+
+        if (FeatureFlags.isEnabled(FeatureFlags.EXTENSIONS)) {
+            // ExtensionProxyAction
+            actions.register(ExtensionProxyAction.INSTANCE, ExtensionProxyTransportAction.class);
+        }
+
+        // Decommission actions
+        actions.register(DecommissionAction.INSTANCE, TransportDecommissionAction.class);
+        actions.register(GetDecommissionStateAction.INSTANCE, TransportGetDecommissionStateAction.class);
+        actions.register(DeleteDecommissionStateAction.INSTANCE, TransportDeleteDecommissionStateAction.class);
+
+        // Search Pipelines
+        actions.register(PutSearchPipelineAction.INSTANCE, PutSearchPipelineTransportAction.class);
+        actions.register(GetSearchPipelineAction.INSTANCE, GetSearchPipelineTransportAction.class);
+        actions.register(DeleteSearchPipelineAction.INSTANCE, DeleteSearchPipelineTransportAction.class);
+
         return unmodifiableMap(actions.getRegistry());
     }
 
@@ -724,6 +825,10 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
         registerHandler.accept(new RestOpenIndexAction());
         registerHandler.accept(new RestAddIndexBlockAction());
 
+        registerHandler.accept(new RestClusterPutWeightedRoutingAction());
+        registerHandler.accept(new RestClusterGetWeightedRoutingAction());
+        registerHandler.accept(new RestClusterDeleteWeightedRoutingAction());
+
         registerHandler.accept(new RestUpdateSettingsAction());
         registerHandler.accept(new RestGetSettingsAction());
 
@@ -812,8 +917,9 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
 
         // CAT API
         registerHandler.accept(new RestAllocationAction());
+        registerHandler.accept(new RestCatSegmentReplicationAction());
         registerHandler.accept(new RestShardsAction());
-        registerHandler.accept(new RestMasterAction());
+        registerHandler.accept(new RestClusterManagerAction());
         registerHandler.accept(new RestNodesAction());
         registerHandler.accept(new RestTasksAction(nodesInCluster));
         registerHandler.accept(new RestIndicesAction());
@@ -832,6 +938,24 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
         registerHandler.accept(new RestRepositoriesAction());
         registerHandler.accept(new RestSnapshotAction());
         registerHandler.accept(new RestTemplatesAction());
+
+        // Point in time API
+        registerHandler.accept(new RestCreatePitAction());
+        registerHandler.accept(new RestDeletePitAction());
+        registerHandler.accept(new RestGetAllPitsAction(nodesInCluster));
+        registerHandler.accept(new RestPitSegmentsAction(nodesInCluster));
+        registerHandler.accept(new RestDeleteDecommissionStateAction());
+
+        // Search pipelines API
+        registerHandler.accept(new RestPutSearchPipelineAction());
+        registerHandler.accept(new RestGetSearchPipelineAction());
+        registerHandler.accept(new RestDeleteSearchPipelineAction());
+
+        // Extensions API
+        if (FeatureFlags.isEnabled(FeatureFlags.EXTENSIONS)) {
+            registerHandler.accept(new RestInitializeExtensionAction(extensionsManager));
+        }
+
         for (ActionPlugin plugin : actionPlugins) {
             for (RestHandler handler : plugin.getRestHandlers(
                 settings,
@@ -846,6 +970,10 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
             }
         }
         registerHandler.accept(new RestCatAction(catActions));
+        registerHandler.accept(new RestDecommissionAction());
+        registerHandler.accept(new RestGetDecommissionStateAction());
+        registerHandler.accept(new RestRemoteStoreStatsAction());
+        registerHandler.accept(new RestRestoreRemoteStoreAction());
     }
 
     @Override
@@ -876,13 +1004,166 @@ protected void configure() {
                 bind(supportAction).asEagerSingleton();
             }
         }
+
+        // register dynamic ActionType -> transportAction Map used by NodeClient
+        bind(DynamicActionRegistry.class).toInstance(dynamicActionRegistry);
     }
 
     public ActionFilters getActionFilters() {
         return actionFilters;
     }
 
+    public DynamicActionRegistry getDynamicActionRegistry() {
+        return dynamicActionRegistry;
+    }
+
     public RestController getRestController() {
         return restController;
     }
+
+    /**
+     * The DynamicActionRegistry maintains a registry mapping {@link ActionType} instances to {@link TransportAction} instances.
+     * <p>
+     * This class is modeled after {@link NamedRegistry} but provides both register and unregister capabilities.
+     *
+     * @opensearch.internal
+     */
+    public static class DynamicActionRegistry {
+        // This is the unmodifiable actions map created during node bootstrap, which
+        // will continue to link ActionType and TransportAction pairs from core and plugin
+        // action handler registration.
+        private Map<ActionType, TransportAction> actions = Collections.emptyMap();
+        // A dynamic registry to add or remove ActionType / TransportAction pairs
+        // at times other than node bootstrap.
+        private final Map<ActionType<?>, TransportAction<?, ?>> registry = new ConcurrentHashMap<>();
+
+        // A dynamic registry to add or remove Route / RestSendToExtensionAction pairs
+        // at times other than node bootstrap.
+        private final Map<NamedRoute, RestSendToExtensionAction> routeRegistry = new ConcurrentHashMap<>();
+
+        private final Set<String> registeredActionNames = new ConcurrentSkipListSet<>();
+
+        /**
+         * Register the immutable actions in the registry.
+         *
+         * @param actions The injected map of {@link ActionType} to {@link TransportAction}
+         */
+        public void registerUnmodifiableActionMap(Map<ActionType, TransportAction> actions) {
+            this.actions = actions;
+            for (ActionType action : actions.keySet()) {
+                registeredActionNames.add(action.name());
+            }
+        }
+
+        /**
+         * Add a dynamic action to the registry.
+         *
+         * @param action The action instance to add
+         * @param transportAction The corresponding instance of transportAction to execute
+         */
+        public void registerDynamicAction(ActionType<?> action, TransportAction<?, ?> transportAction) {
+            requireNonNull(action, "action is required");
+            requireNonNull(transportAction, "transportAction is required");
+            if (actions.containsKey(action) || registry.putIfAbsent(action, transportAction) != null) {
+                throw new IllegalArgumentException("action [" + action.name() + "] already registered");
+            }
+            registeredActionNames.add(action.name());
+        }
+
+        /**
+         * Remove a dynamic action from the registry.
+         *
+         * @param action The action to remove
+         */
+        public void unregisterDynamicAction(ActionType<?> action) {
+            requireNonNull(action, "action is required");
+            if (registry.remove(action) == null) {
+                throw new IllegalArgumentException("action [" + action.name() + "] was not registered");
+            }
+            registeredActionNames.remove(action.name());
+        }
+
+        /**
+         * Checks to see if an action is registered provided an action name
+         *
+         * @param actionName The name of the action to check
+         */
+        public boolean isActionRegistered(String actionName) {
+            return registeredActionNames.contains(actionName);
+        }
+
+        /**
+         * Gets the {@link TransportAction} instance corresponding to the {@link ActionType} instance.
+         *
+         * @param action The {@link ActionType}.
+         * @return the corresponding {@link TransportAction} if it is registered, null otherwise.
+         */
+        @SuppressWarnings("unchecked")
+        public TransportAction<? extends ActionRequest, ? extends ActionResponse> get(ActionType<?> action) {
+            if (actions.containsKey(action)) {
+                return actions.get(action);
+            }
+            return registry.get(action);
+        }
+
+        /**
+         * Adds a dynamic route to the registry.
+         *
+         * @param route The route instance to add
+         * @param action The corresponding instance of RestSendToExtensionAction to execute
+         */
+        public void registerDynamicRoute(NamedRoute route, RestSendToExtensionAction action) {
+            requireNonNull(route, "route is required");
+            requireNonNull(action, "action is required");
+
+            String routeName = route.name();
+            requireNonNull(routeName, "route name is required");
+            if (isActionRegistered(routeName)) {
+                throw new IllegalArgumentException("route [" + route + "] already registered");
+            }
+
+            Set<String> actionNames = route.actionNames();
+            if (!Collections.disjoint(actionNames, registeredActionNames)) {
+                Set<String> alreadyRegistered = new HashSet<>(registeredActionNames);
+                alreadyRegistered.retainAll(actionNames);
+                String acts = String.join(", ", alreadyRegistered);
+                throw new IllegalArgumentException(
+                    "action" + (alreadyRegistered.size() > 1 ? "s [" : " [") + acts + "] already registered"
+                );
+            }
+
+            if (routeRegistry.containsKey(route)) {
+                throw new IllegalArgumentException("route [" + route + "] already registered");
+            }
+            routeRegistry.put(route, action);
+            registeredActionNames.add(routeName);
+            registeredActionNames.addAll(actionNames);
+        }
+
+        /**
+         * Remove a dynamic route from the registry.
+         *
+         * @param route The route to remove
+         */
+        public void unregisterDynamicRoute(NamedRoute route) {
+            requireNonNull(route, "route is required");
+            if (routeRegistry.remove(route) == null) {
+                throw new IllegalArgumentException("action [" + route + "] was not registered");
+            }
+
+            registeredActionNames.remove(route.name());
+            registeredActionNames.removeAll(route.actionNames());
+        }
+
+        /**
+         * Gets the {@link RestSendToExtensionAction} instance corresponding to the {@link RestHandler.Route} instance.
+         *
+         * @param route The {@link RestHandler.Route}.
+         * @return the corresponding {@link RestSendToExtensionAction} if it is registered, null otherwise.
+         */
+        @SuppressWarnings("unchecked")
+        public RestSendToExtensionAction get(RestHandler.Route route) {
+            return routeRegistry.get(route);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/ActionRequest.java b/server/src/main/java/org/opensearch/action/ActionRequest.java
index d000155c55b7d..80511a7ded4f6 100644
--- a/server/src/main/java/org/opensearch/action/ActionRequest.java
+++ b/server/src/main/java/org/opensearch/action/ActionRequest.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.action;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Base action request
+ *
+ * @opensearch.internal
+ */
 public abstract class ActionRequest extends TransportRequest {
 
     public ActionRequest() {
diff --git a/server/src/main/java/org/opensearch/action/ActionRequestBuilder.java b/server/src/main/java/org/opensearch/action/ActionRequestBuilder.java
index 7a81d07c6927a..765d0004d744c 100644
--- a/server/src/main/java/org/opensearch/action/ActionRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/ActionRequestBuilder.java
@@ -33,10 +33,18 @@
 package org.opensearch.action;
 
 import org.opensearch.client.OpenSearchClient;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 
 import java.util.Objects;
 
+/**
+ * Base Action Request Builder
+ *
+ * @opensearch.internal
+ */
 public abstract class ActionRequestBuilder<Request extends ActionRequest, Response extends ActionResponse> {
 
     protected final ActionType<Response> action;
diff --git a/server/src/main/java/org/opensearch/action/ActionRequestValidationException.java b/server/src/main/java/org/opensearch/action/ActionRequestValidationException.java
index 7ada8cdc77f14..d7da932c4dfc2 100644
--- a/server/src/main/java/org/opensearch/action/ActionRequestValidationException.java
+++ b/server/src/main/java/org/opensearch/action/ActionRequestValidationException.java
@@ -34,4 +34,9 @@
 
 import org.opensearch.common.ValidationException;
 
+/**
+ * Base exception for an action request validation
+ *
+ * @opensearch.internal
+ */
 public class ActionRequestValidationException extends ValidationException {}
diff --git a/server/src/main/java/org/opensearch/action/ActionRunnable.java b/server/src/main/java/org/opensearch/action/ActionRunnable.java
index 84b04214e79ee..c8228739ae58e 100644
--- a/server/src/main/java/org/opensearch/action/ActionRunnable.java
+++ b/server/src/main/java/org/opensearch/action/ActionRunnable.java
@@ -36,10 +36,13 @@
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * Base class for {@link Runnable}s that need to call {@link ActionListener#onFailure(Exception)} in case an uncaught
  * exception or error is thrown while the actual action is run.
+ *
+ * @opensearch.internal
  */
 public abstract class ActionRunnable<Response> extends AbstractRunnable {
 
diff --git a/server/src/main/java/org/opensearch/action/ActionType.java b/server/src/main/java/org/opensearch/action/ActionType.java
index fbc9524ce4e52..b9798507705d4 100644
--- a/server/src/main/java/org/opensearch/action/ActionType.java
+++ b/server/src/main/java/org/opensearch/action/ActionType.java
@@ -32,12 +32,16 @@
 
 package org.opensearch.action;
 
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.transport.TransportRequestOptions;
 
 /**
  * A generic action. Should strive to make it a singleton.
+ *
+ * @opensearch.internal
  */
 public class ActionType<Response extends ActionResponse> {
 
@@ -61,7 +65,7 @@ public String name() {
     }
 
     /**
-     * Get a reader that can create a new instance of the class from a {@link org.opensearch.common.io.stream.StreamInput}
+     * Get a reader that can create a new instance of the class from a {@link StreamInput}
      */
     public Writeable.Reader<Response> getResponseReader() {
         return responseReader;
diff --git a/server/src/main/java/org/opensearch/action/AliasesRequest.java b/server/src/main/java/org/opensearch/action/AliasesRequest.java
index a33db646cebba..4c5d5628b1aac 100644
--- a/server/src/main/java/org/opensearch/action/AliasesRequest.java
+++ b/server/src/main/java/org/opensearch/action/AliasesRequest.java
@@ -37,6 +37,8 @@
  * one or more indices and one or more aliases. Meant to be used for aliases management requests (e.g. add/remove alias,
  * get aliases) that hold aliases and indices in separate fields.
  * Allows to retrieve which indices and aliases the action relates to.
+ *
+ * @opensearch.internal
  */
 public interface AliasesRequest extends IndicesRequest.Replaceable {
 
diff --git a/server/src/main/java/org/opensearch/action/CompositeIndicesRequest.java b/server/src/main/java/org/opensearch/action/CompositeIndicesRequest.java
index 25ef0d220beec..1ec2350e713df 100644
--- a/server/src/main/java/org/opensearch/action/CompositeIndicesRequest.java
+++ b/server/src/main/java/org/opensearch/action/CompositeIndicesRequest.java
@@ -37,5 +37,7 @@
  * multiple sub-requests which relate to one or more indices.  A composite request is executed by its own transport action class
  * (e.g. {@link org.opensearch.action.search.TransportMultiSearchAction}), which goes through all sub-requests and delegates their
  * execution to the appropriate transport action (e.g. {@link org.opensearch.action.search.TransportSearchAction}) for each single item.
+ *
+ * @opensearch.internal
  */
 public interface CompositeIndicesRequest {}
diff --git a/server/src/main/java/org/opensearch/action/DocWriteRequest.java b/server/src/main/java/org/opensearch/action/DocWriteRequest.java
index 11d645435c71c..e5979e93d7040 100644
--- a/server/src/main/java/org/opensearch/action/DocWriteRequest.java
+++ b/server/src/main/java/org/opensearch/action/DocWriteRequest.java
@@ -32,16 +32,17 @@
 package org.opensearch.action;
 
 import org.apache.lucene.util.Accountable;
+import org.apache.lucene.util.UnicodeUtil;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.VersionType;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -53,6 +54,8 @@
 /**
  * Generic interface to group ActionRequest, which perform writes to a single document
  * Action requests implementing this can be part of {@link org.opensearch.action.bulk.BulkRequest}
+ *
+ * @opensearch.internal
  */
 public interface DocWriteRequest<T> extends IndicesRequest, Accountable {
 
@@ -247,6 +250,25 @@ static DocWriteRequest<?> readDocumentRequest(@Nullable ShardId shardId, StreamI
         return docWriteRequest;
     }
 
+    /**
+     * Validates whether the doc id length is under the limit.
+     * @param id DocId to verify
+     * @param validationException containing all the validation errors.
+     * @return validationException
+     */
+    static ActionRequestValidationException validateDocIdLength(String id, ActionRequestValidationException validationException) {
+        if (id != null) {
+            int docIdLength = UnicodeUtil.calcUTF16toUTF8Length(id, 0, id.length());
+            if (docIdLength > 512) {
+                return addValidationError(
+                    "id [" + id + "] is too long, must be no longer than 512 bytes but was: " + docIdLength,
+                    validationException
+                );
+            }
+        }
+        return validationException;
+    }
+
     /** write a document write (index/delete/update) request*/
     static void writeDocumentRequest(StreamOutput out, DocWriteRequest<?> request) throws IOException {
         if (request instanceof IndexRequest) {
diff --git a/server/src/main/java/org/opensearch/action/DocWriteResponse.java b/server/src/main/java/org/opensearch/action/DocWriteResponse.java
index 587f93ed09f52..afdb1d3a0bdd9 100644
--- a/server/src/main/java/org/opensearch/action/DocWriteResponse.java
+++ b/server/src/main/java/org/opensearch/action/DocWriteResponse.java
@@ -38,18 +38,18 @@
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
@@ -57,12 +57,14 @@
 import java.util.Locale;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 
 /**
  * A base class for the response of a write operation that involves a single doc
+ *
+ * @opensearch.internal
  */
 public abstract class DocWriteResponse extends ReplicationResponse implements WriteResponse, StatusToXContentObject {
 
@@ -389,6 +391,8 @@ protected static void parseInnerToXContent(XContentParser parser, Builder contex
      * Base class of all {@link DocWriteResponse} builders. These {@link DocWriteResponse.Builder} are used during
      * xcontent parsing to temporarily store the parsed values, then the {@link Builder#build()} method is called to
      * instantiate the appropriate {@link DocWriteResponse} with the parsed values.
+     *
+     * @opensearch.internal
      */
     public abstract static class Builder {
 
diff --git a/server/src/main/java/org/opensearch/action/FailedNodeException.java b/server/src/main/java/org/opensearch/action/FailedNodeException.java
index b4927d0b40a6a..cebcbd38741a0 100644
--- a/server/src/main/java/org/opensearch/action/FailedNodeException.java
+++ b/server/src/main/java/org/opensearch/action/FailedNodeException.java
@@ -33,12 +33,17 @@
 package org.opensearch.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Base exception for a failed node
+ *
+ * @opensearch.internal
+ */
 public class FailedNodeException extends OpenSearchException {
 
     private final String nodeId;
diff --git a/server/src/main/java/org/opensearch/action/IndicesRequest.java b/server/src/main/java/org/opensearch/action/IndicesRequest.java
index 18da6ed0f62b2..7e4c2f5076cda 100644
--- a/server/src/main/java/org/opensearch/action/IndicesRequest.java
+++ b/server/src/main/java/org/opensearch/action/IndicesRequest.java
@@ -39,6 +39,8 @@
  * one or more indices. Allows to retrieve which indices the action relates to.
  * In case of internal requests originated during the distributed execution of an external request,
  * they will still return the indices that the original request related to.
+ *
+ * @opensearch.internal
  */
 public interface IndicesRequest {
 
@@ -62,6 +64,11 @@ default boolean includeDataStreams() {
         return false;
     }
 
+    /**
+     * Replaceable interface.
+     *
+     * @opensearch.internal
+     */
     interface Replaceable extends IndicesRequest {
         /**
          * Sets the indices that the action relates to.
diff --git a/server/src/main/java/org/opensearch/action/LatchedActionListener.java b/server/src/main/java/org/opensearch/action/LatchedActionListener.java
index 4a79cfd898a85..c2400d3b59850 100644
--- a/server/src/main/java/org/opensearch/action/LatchedActionListener.java
+++ b/server/src/main/java/org/opensearch/action/LatchedActionListener.java
@@ -32,11 +32,15 @@
 
 package org.opensearch.action;
 
+import org.opensearch.core.action.ActionListener;
+
 import java.util.concurrent.CountDownLatch;
 
 /**
  * An action listener that allows passing in a {@link CountDownLatch} that
  * will be counted down after onResponse or onFailure is called
+ *
+ * @opensearch.internal
  */
 public class LatchedActionListener<T> implements ActionListener<T> {
 
diff --git a/server/src/main/java/org/opensearch/action/ListenableActionFuture.java b/server/src/main/java/org/opensearch/action/ListenableActionFuture.java
index 9c8510a06173c..1679ec804643e 100644
--- a/server/src/main/java/org/opensearch/action/ListenableActionFuture.java
+++ b/server/src/main/java/org/opensearch/action/ListenableActionFuture.java
@@ -32,10 +32,13 @@
 
 package org.opensearch.action;
 
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.core.action.ActionListener;
+
 /**
  * An {@link ActionFuture} that listeners can be added to.
  *
- *
+ * @opensearch.internal
  */
 public interface ListenableActionFuture<T> extends ActionFuture<T> {
 
diff --git a/server/src/main/java/org/opensearch/action/NoShardAvailableActionException.java b/server/src/main/java/org/opensearch/action/NoShardAvailableActionException.java
index 4e1571d8007f6..d90ddeeba69af 100644
--- a/server/src/main/java/org/opensearch/action/NoShardAvailableActionException.java
+++ b/server/src/main/java/org/opensearch/action/NoShardAvailableActionException.java
@@ -33,12 +33,17 @@
 package org.opensearch.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Base exception for no shard available
+ *
+ * @opensearch.internal
+ */
 public class NoShardAvailableActionException extends OpenSearchException {
 
     public NoShardAvailableActionException(ShardId shardId) {
diff --git a/server/src/main/java/org/opensearch/action/NoSuchNodeException.java b/server/src/main/java/org/opensearch/action/NoSuchNodeException.java
index 898a3d124111c..58fa110973b2c 100644
--- a/server/src/main/java/org/opensearch/action/NoSuchNodeException.java
+++ b/server/src/main/java/org/opensearch/action/NoSuchNodeException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.action;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Base exception for no node found
+ *
+ * @opensearch.internal
+ */
 public class NoSuchNodeException extends FailedNodeException {
 
     public NoSuchNodeException(String nodeId) {
diff --git a/server/src/main/java/org/opensearch/action/OriginalIndices.java b/server/src/main/java/org/opensearch/action/OriginalIndices.java
index 759585fb499a0..1e24c64bc60fc 100644
--- a/server/src/main/java/org/opensearch/action/OriginalIndices.java
+++ b/server/src/main/java/org/opensearch/action/OriginalIndices.java
@@ -33,14 +33,16 @@
 package org.opensearch.action;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
 
 /**
  * Used to keep track of original indices within internal (e.g. shard level) requests
+ *
+ * @opensearch.internal
  */
 public final class OriginalIndices implements IndicesRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/PrimaryMissingActionException.java b/server/src/main/java/org/opensearch/action/PrimaryMissingActionException.java
index 57ae5056d6cd9..959a2ee655fe1 100644
--- a/server/src/main/java/org/opensearch/action/PrimaryMissingActionException.java
+++ b/server/src/main/java/org/opensearch/action/PrimaryMissingActionException.java
@@ -33,10 +33,15 @@
 package org.opensearch.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Base exception for a missing action on a primary
+ *
+ * @opensearch.internal
+ */
 public class PrimaryMissingActionException extends OpenSearchException {
 
     public PrimaryMissingActionException(String message) {
diff --git a/server/src/main/java/org/opensearch/action/RealtimeRequest.java b/server/src/main/java/org/opensearch/action/RealtimeRequest.java
index 37865a6cbff8d..0ceb79ec903d9 100644
--- a/server/src/main/java/org/opensearch/action/RealtimeRequest.java
+++ b/server/src/main/java/org/opensearch/action/RealtimeRequest.java
@@ -35,6 +35,8 @@
 /**
  * Indicates that a request can execute in realtime (reads from the translog).
  * All {@link ActionRequest} that are realtime should implement this interface.
+ *
+ * @opensearch.internal
  */
 public interface RealtimeRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/RequestValidators.java b/server/src/main/java/org/opensearch/action/RequestValidators.java
index 44245c0906882..5cdf20616afc5 100644
--- a/server/src/main/java/org/opensearch/action/RequestValidators.java
+++ b/server/src/main/java/org/opensearch/action/RequestValidators.java
@@ -33,11 +33,16 @@
 package org.opensearch.action;
 
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Collection;
 import java.util.Optional;
 
+/**
+ * Validates transport requests
+ *
+ * @opensearch.internal
+ */
 public class RequestValidators<T extends ActionRequest> {
 
     private final Collection<RequestValidator<T>> validators;
diff --git a/server/src/main/java/org/opensearch/action/RoutingMissingException.java b/server/src/main/java/org/opensearch/action/RoutingMissingException.java
index 4f34a7847da4d..f99e86820bbb2 100644
--- a/server/src/main/java/org/opensearch/action/RoutingMissingException.java
+++ b/server/src/main/java/org/opensearch/action/RoutingMissingException.java
@@ -33,14 +33,19 @@
 package org.opensearch.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Base exception for a missing routing
+ *
+ * @opensearch.internal
+ */
 public class RoutingMissingException extends OpenSearchException {
 
     private final String type;
diff --git a/server/src/main/java/org/opensearch/action/StepListener.java b/server/src/main/java/org/opensearch/action/StepListener.java
index 9547494c753c2..5701d20db90b8 100644
--- a/server/src/main/java/org/opensearch/action/StepListener.java
+++ b/server/src/main/java/org/opensearch/action/StepListener.java
@@ -33,9 +33,11 @@
 package org.opensearch.action;
 
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.FutureUtils;
 import org.opensearch.common.util.concurrent.ListenableFuture;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.NotifyOnceListener;
 
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
@@ -61,6 +63,8 @@
  *    }, flowListener::onFailure);
  *  }
  * }</pre>
+ *
+ * @opensearch.internal
  */
 
 public final class StepListener<Response> extends NotifyOnceListener<Response> {
diff --git a/server/src/main/java/org/opensearch/action/TaskOperationFailure.java b/server/src/main/java/org/opensearch/action/TaskOperationFailure.java
index 09895e5f46db4..0930bd2741810 100644
--- a/server/src/main/java/org/opensearch/action/TaskOperationFailure.java
+++ b/server/src/main/java/org/opensearch/action/TaskOperationFailure.java
@@ -32,26 +32,28 @@
 
 package org.opensearch.action;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Information about task operation failures
  *
  * The class is final due to serialization limitations
+ *
+ * @opensearch.internal
  */
 public final class TaskOperationFailure implements Writeable, ToXContentFragment {
     private static final String TASK_ID = "task_id";
diff --git a/server/src/main/java/org/opensearch/action/ThreadingModel.java b/server/src/main/java/org/opensearch/action/ThreadingModel.java
index 93e96836941e4..11c61152e5107 100644
--- a/server/src/main/java/org/opensearch/action/ThreadingModel.java
+++ b/server/src/main/java/org/opensearch/action/ThreadingModel.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.action;
 
+/**
+ * Threading model
+ *
+ * @opensearch.internal
+ */
 public enum ThreadingModel {
     NONE((byte) 0),
     OPERATION((byte) 1),
diff --git a/server/src/main/java/org/opensearch/action/TimestampParsingException.java b/server/src/main/java/org/opensearch/action/TimestampParsingException.java
index f6a0207f22db7..25e22a6dfb6c3 100644
--- a/server/src/main/java/org/opensearch/action/TimestampParsingException.java
+++ b/server/src/main/java/org/opensearch/action/TimestampParsingException.java
@@ -33,11 +33,16 @@
 package org.opensearch.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Base exception for a failed timestamp parse
+ *
+ * @opensearch.internal
+ */
 public class TimestampParsingException extends OpenSearchException {
 
     private final String timestamp;
diff --git a/server/src/main/java/org/opensearch/action/TransportActionNodeProxy.java b/server/src/main/java/org/opensearch/action/TransportActionNodeProxy.java
index 8c6838b186fca..1088a3a4f8679 100644
--- a/server/src/main/java/org/opensearch/action/TransportActionNodeProxy.java
+++ b/server/src/main/java/org/opensearch/action/TransportActionNodeProxy.java
@@ -34,11 +34,15 @@
 
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportService;
 
 /**
  * A generic proxy that will execute the given action against a specific node.
+ *
+ * @opensearch.internal
  */
 public class TransportActionNodeProxy<Request extends ActionRequest, Response extends ActionResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/UnavailableShardsException.java b/server/src/main/java/org/opensearch/action/UnavailableShardsException.java
index a6050ae9a3c75..706d9bb38ed13 100644
--- a/server/src/main/java/org/opensearch/action/UnavailableShardsException.java
+++ b/server/src/main/java/org/opensearch/action/UnavailableShardsException.java
@@ -34,12 +34,17 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Base exception for shards unavailable
+ *
+ * @opensearch.internal
+ */
 public class UnavailableShardsException extends OpenSearchException {
 
     public UnavailableShardsException(@Nullable ShardId shardId, String message, Object... args) {
diff --git a/server/src/main/java/org/opensearch/action/ValidateActions.java b/server/src/main/java/org/opensearch/action/ValidateActions.java
index 134a880c7a972..1d1591ae3049b 100644
--- a/server/src/main/java/org/opensearch/action/ValidateActions.java
+++ b/server/src/main/java/org/opensearch/action/ValidateActions.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.action;
 
+/**
+ * Validates transport actions
+ *
+ * @opensearch.internal
+ */
 public class ValidateActions {
 
     public static ActionRequestValidationException addValidationError(String error, ActionRequestValidationException validationException) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainAction.java
index 4c95d1e336b3a..0e99513a8fc7e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainAction.java
@@ -36,6 +36,8 @@
 
 /**
  * ActionType for explaining shard allocation for a shard in the cluster
+ *
+ * @opensearch.internal
  */
 public class ClusterAllocationExplainAction extends ActionType<ClusterAllocationExplainResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequest.java
index 1a055fa0d14c2..625aa91e6ea7f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequest.java
@@ -33,13 +33,13 @@
 package org.opensearch.action.admin.cluster.allocation;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
@@ -47,8 +47,10 @@
 
 /**
  * A request to explain the allocation of a shard in the cluster
+ *
+ * @opensearch.internal
  */
-public class ClusterAllocationExplainRequest extends MasterNodeRequest<ClusterAllocationExplainRequest> {
+public class ClusterAllocationExplainRequest extends ClusterManagerNodeRequest<ClusterAllocationExplainRequest> {
 
     private static final ObjectParser<ClusterAllocationExplainRequest, Void> PARSER = new ObjectParser<>("cluster/allocation/explain");
     static {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequestBuilder.java
index 78a22cd59b284..d85cb3929873d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainRequestBuilder.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.action.admin.cluster.allocation;
 
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
 /**
  * Builder for requests to explain the allocation of a shard in the cluster
+ *
+ * @opensearch.internal
  */
-public class ClusterAllocationExplainRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class ClusterAllocationExplainRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     ClusterAllocationExplainRequest,
     ClusterAllocationExplainResponse,
     ClusterAllocationExplainRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainResponse.java
index 2fc72ccb13e28..0eeedb9af0ab7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainResponse.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.cluster.allocation;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Explanation response for a shard in the cluster
+ *
+ * @opensearch.internal
  */
 public class ClusterAllocationExplainResponse extends ActionResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanation.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanation.java
index e9505c7fc83c2..f4705a21f5014 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanation.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanation.java
@@ -40,12 +40,12 @@
 import org.opensearch.cluster.routing.allocation.AllocationDecision;
 import org.opensearch.cluster.routing.allocation.ShardAllocationDecision;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -57,6 +57,8 @@
  * A {@code ClusterAllocationExplanation} is an explanation of why a shard is unassigned,
  * or if it is not unassigned, then which nodes it could possibly be relocated to.
  * It is an immutable class.
+ *
+ * @opensearch.internal
  */
 public final class ClusterAllocationExplanation implements ToXContentObject, Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/TransportClusterAllocationExplainAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/TransportClusterAllocationExplainAction.java
index 95fbe42384238..737155b13a708 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/TransportClusterAllocationExplainAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/TransportClusterAllocationExplainAction.java
@@ -34,9 +34,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterInfo;
 import org.opensearch.cluster.ClusterInfoService;
 import org.opensearch.cluster.ClusterState;
@@ -54,7 +53,8 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.SnapshotsInfoService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -64,9 +64,11 @@
 
 /**
  * The {@code TransportClusterAllocationExplainAction} is responsible for actually executing the explanation of a shard's allocation on the
- * master node in the cluster.
+ * cluster-manager node in the cluster.
+ *
+ * @opensearch.internal
  */
-public class TransportClusterAllocationExplainAction extends TransportMasterNodeAction<
+public class TransportClusterAllocationExplainAction extends TransportClusterManagerNodeAction<
     ClusterAllocationExplainRequest,
     ClusterAllocationExplainResponse> {
 
@@ -123,7 +125,7 @@ protected ClusterBlockException checkBlock(ClusterAllocationExplainRequest reque
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ClusterAllocationExplainRequest request,
         final ClusterState state,
         final ActionListener<ClusterAllocationExplainResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/allocation/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/package-info.java
new file mode 100644
index 0000000000000..ef38d39ede82a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/allocation/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster allocation transport handlers. */
+package org.opensearch.action.admin.cluster.allocation;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsAction.java
index 963a5d567c0bc..4a4f28b360801 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsAction.java
@@ -33,7 +33,12 @@
 
 import org.opensearch.action.ActionType;
 
-public class AddVotingConfigExclusionsAction extends ActionType<AddVotingConfigExclusionsResponse> {
+/**
+ * Transport endpoint for adding exclusions to voting config
+ *
+ * @opensearch.internal
+ */
+public final class AddVotingConfigExclusionsAction extends ActionType<AddVotingConfigExclusionsResponse> {
     public static final AddVotingConfigExclusionsAction INSTANCE = new AddVotingConfigExclusionsAction();
     public static final String NAME = "cluster:admin/voting_config/add_exclusions";
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequest.java
index 99291742145f0..2fd4557ebc7ee 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequest.java
@@ -33,16 +33,16 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -54,10 +54,12 @@
 import java.util.stream.StreamSupport;
 
 /**
- * A request to add voting config exclusions for certain master-eligible nodes, and wait for these nodes to be removed from the voting
+ * A request to add voting config exclusions for certain cluster-manager-eligible nodes, and wait for these nodes to be removed from the voting
  * configuration.
+ *
+ * @opensearch.internal
  */
-public class AddVotingConfigExclusionsRequest extends MasterNodeRequest<AddVotingConfigExclusionsRequest> {
+public class AddVotingConfigExclusionsRequest extends ClusterManagerNodeRequest<AddVotingConfigExclusionsRequest> {
     public static final String DEPRECATION_MESSAGE = "nodeDescription is deprecated and will be removed, use nodeIds or nodeNames instead";
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(AddVotingConfigExclusionsRequest.class);
     private final String[] nodeDescriptions;
@@ -66,7 +68,7 @@ public class AddVotingConfigExclusionsRequest extends MasterNodeRequest<AddVotin
     private final TimeValue timeout;
 
     /**
-     * Construct a request to add voting config exclusions for master-eligible nodes matching the given node names, and wait for a
+     * Construct a request to add voting config exclusions for cluster-manager-eligible nodes matching the given node names, and wait for a
      * default 30 seconds for these exclusions to take effect, removing the nodes from the voting configuration.
      * @param nodeNames Names of the nodes to add - see {@link AddVotingConfigExclusionsRequest#resolveVotingConfigExclusions(ClusterState)}
      */
@@ -75,7 +77,7 @@ public AddVotingConfigExclusionsRequest(String... nodeNames) {
     }
 
     /**
-     * Construct a request to add voting config exclusions for master-eligible nodes matching the given descriptions, and wait for these
+     * Construct a request to add voting config exclusions for cluster-manager-eligible nodes matching the given descriptions, and wait for these
      * nodes to be removed from the voting configuration.
      * @param nodeDescriptions Descriptions of the nodes whose exclusions to add - see {@link DiscoveryNodes#resolveNodes(String...)}.
      * @param nodeIds Ids of the nodes whose exclusions to add - see
@@ -130,20 +132,22 @@ Set<VotingConfigExclusion> resolveVotingConfigExclusions(ClusterState currentSta
         if (nodeDescriptions.length >= 1) {
             newVotingConfigExclusions = Arrays.stream(allNodes.resolveNodes(nodeDescriptions))
                 .map(allNodes::get)
-                .filter(DiscoveryNode::isMasterNode)
+                .filter(DiscoveryNode::isClusterManagerNode)
                 .map(VotingConfigExclusion::new)
                 .collect(Collectors.toSet());
 
             if (newVotingConfigExclusions.isEmpty()) {
                 throw new IllegalArgumentException(
-                    "add voting config exclusions request for " + Arrays.asList(nodeDescriptions) + " matched no master-eligible nodes"
+                    "add voting config exclusions request for "
+                        + Arrays.asList(nodeDescriptions)
+                        + " matched no cluster-manager-eligible nodes"
                 );
             }
         } else if (nodeIds.length >= 1) {
             for (String nodeId : nodeIds) {
                 if (allNodes.nodeExists(nodeId)) {
                     DiscoveryNode discoveryNode = allNodes.get(nodeId);
-                    if (discoveryNode.isMasterNode()) {
+                    if (discoveryNode.isClusterManagerNode()) {
                         newVotingConfigExclusions.add(new VotingConfigExclusion(discoveryNode));
                     }
                 } else {
@@ -158,7 +162,7 @@ Set<VotingConfigExclusion> resolveVotingConfigExclusions(ClusterState currentSta
             for (String nodeName : nodeNames) {
                 if (existingNodes.containsKey(nodeName)) {
                     DiscoveryNode discoveryNode = existingNodes.get(nodeName);
-                    if (discoveryNode.isMasterNode()) {
+                    if (discoveryNode.isClusterManagerNode()) {
                         newVotingConfigExclusions.add(new VotingConfigExclusion(discoveryNode));
                     }
                 } else {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsResponse.java
index 0493de7c439de..7855f9643c4ce 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsResponse.java
@@ -31,17 +31,19 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * A response to {@link AddVotingConfigExclusionsRequest} indicating that voting config exclusions have been added for the requested nodes
  * and these nodes have been removed from the voting configuration.
+ *
+ * @opensearch.internal
  */
 public class AddVotingConfigExclusionsResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsAction.java
index ce31abceb6738..e0fcad8f8ccd8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsAction.java
@@ -33,6 +33,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport endpoint for clearing exclusions to voting config
+ *
+ * @opensearch.internal
+ */
 public class ClearVotingConfigExclusionsAction extends ActionType<ClearVotingConfigExclusionsResponse> {
     public static final ClearVotingConfigExclusionsAction INSTANCE = new ClearVotingConfigExclusionsAction();
     public static final String NAME = "cluster:admin/voting_config/clear_exclusions";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsRequest.java
index 9ccccc88f3365..eda0175c90728 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsRequest.java
@@ -32,18 +32,20 @@
 package org.opensearch.action.admin.cluster.configuration;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * A request to clear the voting config exclusions from the cluster state, optionally waiting for these nodes to be removed from the
  * cluster first.
+ *
+ * @opensearch.internal
  */
-public class ClearVotingConfigExclusionsRequest extends MasterNodeRequest<ClearVotingConfigExclusionsRequest> {
+public class ClearVotingConfigExclusionsRequest extends ClusterManagerNodeRequest<ClearVotingConfigExclusionsRequest> {
     private boolean waitForRemoval = true;
     private TimeValue timeout = TimeValue.timeValueSeconds(30);
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsResponse.java
index ed07f33b6c6a6..eb2ccaa7f5390 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/ClearVotingConfigExclusionsResponse.java
@@ -31,17 +31,19 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * A response to {@link ClearVotingConfigExclusionsRequest} indicating that voting config exclusions have been cleared from the
  * cluster state.
+ *
+ * @opensearch.internal
  */
 public class ClearVotingConfigExclusionsResponse extends ActionResponse implements ToXContentObject {
     public ClearVotingConfigExclusionsResponse() {}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsAction.java
index 30ba799db044a..f578925e54ce7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsAction.java
@@ -35,28 +35,26 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.ClusterStateObserver.Listener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.transport.TransportService;
@@ -66,7 +64,15 @@
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
-public class TransportAddVotingConfigExclusionsAction extends TransportMasterNodeAction<
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.addExclusionAndGetState;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.resolveVotingConfigExclusionsAndCheckMaximum;
+
+/**
+ * Transport endpoint action for adding exclusions to voting config
+ *
+ * @opensearch.internal
+ */
+public class TransportAddVotingConfigExclusionsAction extends TransportClusterManagerNodeAction<
     AddVotingConfigExclusionsRequest,
     AddVotingConfigExclusionsResponse> {
 
@@ -121,7 +127,7 @@ protected AddVotingConfigExclusionsResponse read(StreamInput in) throws IOExcept
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         AddVotingConfigExclusionsRequest request,
         ClusterState state,
         ActionListener<AddVotingConfigExclusionsResponse> listener
@@ -139,13 +145,7 @@ public ClusterState execute(ClusterState currentState) {
                 assert resolvedExclusions == null : resolvedExclusions;
                 final int finalMaxVotingConfigExclusions = TransportAddVotingConfigExclusionsAction.this.maxVotingConfigExclusions;
                 resolvedExclusions = resolveVotingConfigExclusionsAndCheckMaximum(request, currentState, finalMaxVotingConfigExclusions);
-
-                final CoordinationMetadata.Builder builder = CoordinationMetadata.builder(currentState.coordinationMetadata());
-                resolvedExclusions.forEach(builder::addVotingConfigExclusion);
-                final Metadata newMetadata = Metadata.builder(currentState.metadata()).coordinationMetadata(builder.build()).build();
-                final ClusterState newState = ClusterState.builder(currentState).metadata(newMetadata).build();
-                assert newState.getVotingConfigExclusions().size() <= finalMaxVotingConfigExclusions;
-                return newState;
+                return addExclusionAndGetState(currentState, resolvedExclusions, finalMaxVotingConfigExclusions);
             }
 
             @Override
@@ -208,18 +208,6 @@ public void onTimeout(TimeValue timeout) {
         });
     }
 
-    private static Set<VotingConfigExclusion> resolveVotingConfigExclusionsAndCheckMaximum(
-        AddVotingConfigExclusionsRequest request,
-        ClusterState state,
-        int maxVotingConfigExclusions
-    ) {
-        return request.resolveVotingConfigExclusionsAndCheckMaximum(
-            state,
-            maxVotingConfigExclusions,
-            MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING.getKey()
-        );
-    }
-
     @Override
     protected ClusterBlockException checkBlock(AddVotingConfigExclusionsRequest request, ClusterState state) {
         return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsAction.java
index 31a1d07608071..c3c08b9636518 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsAction.java
@@ -35,24 +35,22 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.ClusterStateObserver.Listener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.transport.TransportService;
@@ -60,7 +58,14 @@
 import java.io.IOException;
 import java.util.function.Predicate;
 
-public class TransportClearVotingConfigExclusionsAction extends TransportMasterNodeAction<
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.clearExclusionsAndGetState;
+
+/**
+ * Transport endpoint action for clearing exclusions to voting config
+ *
+ * @opensearch.internal
+ */
+public class TransportClearVotingConfigExclusionsAction extends TransportClusterManagerNodeAction<
     ClearVotingConfigExclusionsRequest,
     ClearVotingConfigExclusionsResponse> {
 
@@ -96,7 +101,7 @@ protected ClearVotingConfigExclusionsResponse read(StreamInput in) throws IOExce
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         ClearVotingConfigExclusionsRequest request,
         ClusterState initialState,
         ActionListener<ClearVotingConfigExclusionsResponse> listener
@@ -161,13 +166,7 @@ private void submitClearVotingConfigExclusionsTask(
         clusterService.submitStateUpdateTask("clear-voting-config-exclusions", new ClusterStateUpdateTask(Priority.URGENT) {
             @Override
             public ClusterState execute(ClusterState currentState) {
-                final CoordinationMetadata newCoordinationMetadata = CoordinationMetadata.builder(currentState.coordinationMetadata())
-                    .clearVotingConfigExclusions()
-                    .build();
-                final Metadata newMetadata = Metadata.builder(currentState.metadata())
-                    .coordinationMetadata(newCoordinationMetadata)
-                    .build();
-                return ClusterState.builder(currentState).metadata(newMetadata).build();
+                return clearExclusionsAndGetState(currentState);
             }
 
             @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelper.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelper.java
new file mode 100644
index 0000000000000..5cc4bd2f831d7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelper.java
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.configuration;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
+import org.opensearch.cluster.metadata.Metadata;
+
+import java.util.Set;
+
+import static org.opensearch.action.admin.cluster.configuration.TransportAddVotingConfigExclusionsAction.MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING;
+
+/**
+ * Static helper utilities for voting config exclusions cluster state updates
+ *
+ * @opensearch.internal
+ */
+public class VotingConfigExclusionsHelper {
+
+    /**
+     * Static helper to update current state with given resolved exclusions
+     *
+     * @param currentState current cluster state
+     * @param resolvedExclusions resolved exclusions from the request
+     * @param finalMaxVotingConfigExclusions max exclusions that be added
+     * @return newly formed cluster state
+     */
+    public static ClusterState addExclusionAndGetState(
+        ClusterState currentState,
+        Set<VotingConfigExclusion> resolvedExclusions,
+        int finalMaxVotingConfigExclusions
+    ) {
+        final CoordinationMetadata.Builder builder = CoordinationMetadata.builder(currentState.coordinationMetadata());
+        resolvedExclusions.forEach(builder::addVotingConfigExclusion);
+        final Metadata newMetadata = Metadata.builder(currentState.metadata()).coordinationMetadata(builder.build()).build();
+        final ClusterState newState = ClusterState.builder(currentState).metadata(newMetadata).build();
+        assert newState.getVotingConfigExclusions().size() <= finalMaxVotingConfigExclusions;
+        return newState;
+    }
+
+    /**
+     * Resolves the exclusion from the request and throws IAE if no nodes matched or maximum exceeded
+     *
+     * @param request AddVotingConfigExclusionsRequest request
+     * @param state current cluster state
+     * @param maxVotingConfigExclusions max number of exclusion acceptable
+     * @return set of VotingConfigExclusion
+     */
+    public static Set<VotingConfigExclusion> resolveVotingConfigExclusionsAndCheckMaximum(
+        AddVotingConfigExclusionsRequest request,
+        ClusterState state,
+        int maxVotingConfigExclusions
+    ) {
+        return request.resolveVotingConfigExclusionsAndCheckMaximum(
+            state,
+            maxVotingConfigExclusions,
+            MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING.getKey()
+        );
+    }
+
+    /**
+     * Clears Voting config exclusion from the given cluster state
+     *
+     * @param currentState current cluster state
+     * @return newly formed cluster state after clearing voting config exclusions
+     */
+    public static ClusterState clearExclusionsAndGetState(ClusterState currentState) {
+        final CoordinationMetadata newCoordinationMetadata = CoordinationMetadata.builder(currentState.coordinationMetadata())
+            .clearVotingConfigExclusions()
+            .build();
+        final Metadata newMetadata = Metadata.builder(currentState.metadata()).coordinationMetadata(newCoordinationMetadata).build();
+        return ClusterState.builder(currentState).metadata(newMetadata).build();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/configuration/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/package-info.java
new file mode 100644
index 0000000000000..5543e7a6bde2f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/configuration/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster configuration transport handlers. */
+package org.opensearch.action.admin.cluster.configuration;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/crypto/CryptoSettings.java b/server/src/main/java/org/opensearch/action/admin/cluster/crypto/CryptoSettings.java
new file mode 100644
index 0000000000000..bd783b349bed4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/crypto/CryptoSettings.java
@@ -0,0 +1,181 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.crypto;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Map;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
+import static org.opensearch.common.settings.Settings.readSettingsFromStream;
+import static org.opensearch.common.settings.Settings.writeSettingsToStream;
+
+/**
+ * Crypto settings supplied during a put repository request
+ *
+ * @opensearch.internal
+ */
+public class CryptoSettings implements Writeable, ToXContentObject {
+    private String keyProviderName;
+    private String keyProviderType;
+    private Settings settings = EMPTY_SETTINGS;
+
+    public CryptoSettings(StreamInput in) throws IOException {
+        keyProviderName = in.readString();
+        keyProviderType = in.readString();
+        settings = readSettingsFromStream(in);
+    }
+
+    public CryptoSettings(String keyProviderName) {
+        this.keyProviderName = keyProviderName;
+    }
+
+    /**
+     * Validate settings supplied in put repository request.
+     * @return Exception in case validation fails.
+     */
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (keyProviderName == null) {
+            validationException = addValidationError("key_provider_name is missing", validationException);
+        }
+        if (keyProviderType == null) {
+            validationException = addValidationError("key_provider_type is missing", validationException);
+        }
+        return validationException;
+    }
+
+    /**
+     * Returns key provider name
+     * @return keyProviderName
+     */
+    public String getKeyProviderName() {
+        return keyProviderName;
+    }
+
+    /**
+     * Returns key provider type
+     * @return keyProviderType
+     */
+    public String getKeyProviderType() {
+        return keyProviderType;
+    }
+
+    /**
+     * Returns crypto settings
+     * @return settings
+     */
+    public Settings getSettings() {
+        return settings;
+    }
+
+    /**
+     * Constructs a new crypto settings with provided key provider name.
+     * @param keyProviderName Name of the key provider
+     */
+    public CryptoSettings keyProviderName(String keyProviderName) {
+        this.keyProviderName = keyProviderName;
+        return this;
+    }
+
+    /**
+     * Constructs a new crypto settings with provided key provider type.
+     * @param keyProviderType Type of key provider to be used in encryption.
+     */
+    public CryptoSettings keyProviderType(String keyProviderType) {
+        this.keyProviderType = keyProviderType;
+        return this;
+    }
+
+    /**
+     * Sets the encryption settings
+     *
+     * @param settings for encryption
+     * @return this request
+     */
+    public CryptoSettings settings(Settings.Builder settings) {
+        this.settings = settings.build();
+        return this;
+    }
+
+    /**
+     * Sets the encryption settings.
+     *
+     * @param source encryption settings in json or yaml format
+     * @param xContentType the content type of the source
+     * @return this request
+     */
+    public CryptoSettings settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
+     * Sets the encryption settings.
+     *
+     * @param source encryption settings
+     * @return this request
+     */
+    public CryptoSettings settings(Map<String, Object> source) {
+        this.settings = Settings.builder().loadFromMap(source).build();
+        return this;
+    }
+
+    /**
+     * Parses crypto settings definition.
+     *
+     * @param cryptoDefinition crypto settings definition
+     */
+    public CryptoSettings(Map<String, Object> cryptoDefinition) {
+        for (Map.Entry<String, Object> entry : cryptoDefinition.entrySet()) {
+            if (entry.getKey().equals("key_provider_name")) {
+                keyProviderName(entry.getValue().toString());
+            } else if (entry.getKey().equals("key_provider_type")) {
+                keyProviderType(entry.getValue().toString());
+            } else if (entry.getKey().equals("settings")) {
+                if (!(entry.getValue() instanceof Map)) {
+                    throw new IllegalArgumentException("Malformed settings section in crypto settings, should include an inner object");
+                }
+                @SuppressWarnings("unchecked")
+                Map<String, Object> sub = (Map<String, Object>) entry.getValue();
+                settings(sub);
+            }
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(keyProviderName);
+        out.writeString(keyProviderType);
+        writeSettingsToStream(settings, out);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("key_provider_name", keyProviderName);
+        builder.field("key_provider_type", keyProviderType);
+
+        builder.startObject("settings");
+        settings.toXContent(builder, params);
+        builder.endObject();
+
+        builder.endObject();
+        return builder;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/crypto/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/crypto/package-info.java
new file mode 100644
index 0000000000000..bb9375c20c87e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/crypto/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Crypto client request and settings handlers.
+ */
+package org.opensearch.action.admin.cluster.crypto;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateAction.java
new file mode 100644
index 0000000000000..3aff666d388be
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
+
+import org.opensearch.action.ActionType;
+
+/**
+ *  Delete decommission state action.
+ *
+ * @opensearch.internal
+ */
+public class DeleteDecommissionStateAction extends ActionType<DeleteDecommissionStateResponse> {
+    public static final DeleteDecommissionStateAction INSTANCE = new DeleteDecommissionStateAction();
+    public static final String NAME = "cluster:admin/decommission/awareness/delete";
+
+    private DeleteDecommissionStateAction() {
+        super(NAME, DeleteDecommissionStateResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequest.java
new file mode 100644
index 0000000000000..79b7381801da6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequest.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Request for deleting decommission request.
+ *
+ * @opensearch.internal
+ */
+public class DeleteDecommissionStateRequest extends ClusterManagerNodeRequest<DeleteDecommissionStateRequest> {
+
+    public DeleteDecommissionStateRequest() {}
+
+    public DeleteDecommissionStateRequest(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequestBuilder.java
new file mode 100644
index 0000000000000..08f194c53f18e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateRequestBuilder.java
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
+
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+
+/**
+ * Builder for Delete decommission request.
+ *
+ * @opensearch.internal
+ */
+public class DeleteDecommissionStateRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
+    DeleteDecommissionStateRequest,
+    DeleteDecommissionStateResponse,
+    DeleteDecommissionStateRequestBuilder> {
+
+    public DeleteDecommissionStateRequestBuilder(OpenSearchClient client, DeleteDecommissionStateAction action) {
+        super(client, action, new DeleteDecommissionStateRequest());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateResponse.java
new file mode 100644
index 0000000000000..3d0404c25373b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/DeleteDecommissionStateResponse.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
+
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Response returned after deletion of decommission request.
+ *
+ * @opensearch.internal
+ */
+public class DeleteDecommissionStateResponse extends AcknowledgedResponse {
+
+    public DeleteDecommissionStateResponse(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public DeleteDecommissionStateResponse(boolean acknowledged) {
+        super(acknowledged);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/TransportDeleteDecommissionStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/TransportDeleteDecommissionStateAction.java
new file mode 100644
index 0000000000000..8901375a4095a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/TransportDeleteDecommissionStateAction.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.decommission.DecommissionService;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for delete decommission.
+ *
+ * @opensearch.internal
+ */
+public class TransportDeleteDecommissionStateAction extends TransportClusterManagerNodeAction<
+    DeleteDecommissionStateRequest,
+    DeleteDecommissionStateResponse> {
+
+    private static final Logger logger = LogManager.getLogger(TransportDeleteDecommissionStateAction.class);
+    private final DecommissionService decommissionService;
+
+    @Inject
+    public TransportDeleteDecommissionStateAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        DecommissionService decommissionService
+    ) {
+        super(
+            DeleteDecommissionStateAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            DeleteDecommissionStateRequest::new,
+            indexNameExpressionResolver
+        );
+        this.decommissionService = decommissionService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected DeleteDecommissionStateResponse read(StreamInput in) throws IOException {
+        return new DeleteDecommissionStateResponse(in);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(DeleteDecommissionStateRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        DeleteDecommissionStateRequest request,
+        ClusterState state,
+        ActionListener<DeleteDecommissionStateResponse> listener
+    ) {
+        logger.info("Received delete decommission Request [{}]", request);
+        this.decommissionService.startRecommissionAction(listener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/package-info.java
new file mode 100644
index 0000000000000..c2cfc03baa45e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Delete decommission transport handlers. */
+package org.opensearch.action.admin.cluster.decommission.awareness.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateAction.java
new file mode 100644
index 0000000000000..72fd1a26cb860
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Get decommission action
+ *
+ * @opensearch.internal
+ */
+public class GetDecommissionStateAction extends ActionType<GetDecommissionStateResponse> {
+
+    public static final GetDecommissionStateAction INSTANCE = new GetDecommissionStateAction();
+    public static final String NAME = "cluster:admin/decommission/awareness/get";
+
+    private GetDecommissionStateAction() {
+        super(NAME, GetDecommissionStateResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequest.java
new file mode 100644
index 0000000000000..15c7e165fb62f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequest.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Get Decommissioned attribute request
+ *
+ * @opensearch.internal
+ */
+public class GetDecommissionStateRequest extends ClusterManagerNodeReadRequest<GetDecommissionStateRequest> {
+
+    private String attributeName;
+
+    public GetDecommissionStateRequest() {}
+
+    /**
+     * Constructs a new get decommission state request with given attribute name
+     *
+     * @param attributeName name of the attribute
+     */
+    public GetDecommissionStateRequest(String attributeName) {
+        this.attributeName = attributeName;
+    }
+
+    public GetDecommissionStateRequest(StreamInput in) throws IOException {
+        super(in);
+        attributeName = in.readString();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(attributeName);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (attributeName == null || Strings.isEmpty(attributeName)) {
+            validationException = addValidationError("attribute name is missing", validationException);
+        }
+        return validationException;
+    }
+
+    /**
+     * Sets attribute name
+     *
+     * @param attributeName attribute name
+     * @return this request
+     */
+    public GetDecommissionStateRequest attributeName(String attributeName) {
+        this.attributeName = attributeName;
+        return this;
+    }
+
+    /**
+     * Returns attribute name
+     *
+     * @return attributeName name of attribute
+     */
+    public String attributeName() {
+        return this.attributeName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestBuilder.java
new file mode 100644
index 0000000000000..e766e9c674ff7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestBuilder.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+
+/**
+ * Get decommission request builder
+ *
+ * @opensearch.internal
+ */
+public class GetDecommissionStateRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
+    GetDecommissionStateRequest,
+    GetDecommissionStateResponse,
+    GetDecommissionStateRequestBuilder> {
+
+    /**
+     * Creates new get decommissioned attributes request builder
+     */
+    public GetDecommissionStateRequestBuilder(OpenSearchClient client, GetDecommissionStateAction action) {
+        super(client, action, new GetDecommissionStateRequest());
+    }
+
+    /**
+     * @param attributeName name of attribute
+     * @return current object
+     */
+    public GetDecommissionStateRequestBuilder setAttributeName(String attributeName) {
+        request.attributeName(attributeName);
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponse.java
new file mode 100644
index 0000000000000..bbcbd7013c299
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponse.java
@@ -0,0 +1,121 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Locale;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * Response for decommission status
+ *
+ * @opensearch.internal
+ */
+public class GetDecommissionStateResponse extends ActionResponse implements ToXContentObject {
+
+    private String attributeValue;
+    private DecommissionStatus status;
+
+    GetDecommissionStateResponse() {
+        this(null, null);
+    }
+
+    GetDecommissionStateResponse(String attributeValue, DecommissionStatus status) {
+        this.attributeValue = attributeValue;
+        this.status = status;
+    }
+
+    GetDecommissionStateResponse(StreamInput in) throws IOException {
+        // read decommissioned attribute and status only if it is present
+        if (in.readBoolean()) {
+            this.attributeValue = in.readString();
+            this.status = DecommissionStatus.fromString(in.readString());
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        // if decommissioned attribute value is null or status is null then mark its absence
+        if (attributeValue == null || status == null) {
+            out.writeBoolean(false);
+        } else {
+            out.writeBoolean(true);
+            out.writeString(attributeValue);
+            out.writeString(status.status());
+        }
+    }
+
+    public String getAttributeValue() {
+        return attributeValue;
+    }
+
+    public DecommissionStatus getDecommissionStatus() {
+        return status;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (attributeValue != null && status != null) {
+            builder.field(attributeValue, status);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    public static GetDecommissionStateResponse fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        XContentParser.Token token;
+        String attributeValue = null;
+        DecommissionStatus status = null;
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                attributeValue = parser.currentName();
+                if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                    throw new OpenSearchParseException("failed to parse status of decommissioning, expected string but found unknown type");
+                }
+                status = DecommissionStatus.fromString(parser.text().toLowerCase(Locale.ROOT));
+            } else {
+                throw new OpenSearchParseException(
+                    "failed to parse decommission state, expected [{}] but found [{}]",
+                    XContentParser.Token.FIELD_NAME,
+                    token
+                );
+            }
+        }
+        return new GetDecommissionStateResponse(attributeValue, status);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        GetDecommissionStateResponse that = (GetDecommissionStateResponse) o;
+        if (!Objects.equals(attributeValue, that.attributeValue)) {
+            return false;
+        }
+        return Objects.equals(status, that.status);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributeValue, status);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/TransportGetDecommissionStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/TransportGetDecommissionStateAction.java
new file mode 100644
index 0000000000000..22feb4d99297a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/TransportGetDecommissionStateAction.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for getting decommission status
+ *
+ * @opensearch.internal
+ */
+public class TransportGetDecommissionStateAction extends TransportClusterManagerNodeReadAction<
+    GetDecommissionStateRequest,
+    GetDecommissionStateResponse> {
+
+    @Inject
+    public TransportGetDecommissionStateAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            GetDecommissionStateAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            GetDecommissionStateRequest::new,
+            indexNameExpressionResolver
+        );
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected GetDecommissionStateResponse read(StreamInput in) throws IOException {
+        return new GetDecommissionStateResponse(in);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        GetDecommissionStateRequest request,
+        ClusterState state,
+        ActionListener<GetDecommissionStateResponse> listener
+    ) throws Exception {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = state.metadata().decommissionAttributeMetadata();
+        if (decommissionAttributeMetadata != null
+            && request.attributeName().equals(decommissionAttributeMetadata.decommissionAttribute().attributeName())) {
+            listener.onResponse(
+                new GetDecommissionStateResponse(
+                    decommissionAttributeMetadata.decommissionAttribute().attributeValue(),
+                    decommissionAttributeMetadata.status()
+                )
+            );
+        } else {
+            listener.onResponse(new GetDecommissionStateResponse());
+        }
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(GetDecommissionStateRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/package-info.java
new file mode 100644
index 0000000000000..5b88e91cf4f9d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handlers for getting status of decommission request */
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/package-info.java
new file mode 100644
index 0000000000000..e1260e638c91d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Decommission transport handlers. */
+package org.opensearch.action.admin.cluster.decommission.awareness;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionAction.java
new file mode 100644
index 0000000000000..56678650f6e35
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Register decommission action
+ *
+ * @opensearch.internal
+ */
+public final class DecommissionAction extends ActionType<DecommissionResponse> {
+    public static final DecommissionAction INSTANCE = new DecommissionAction();
+    public static final String NAME = "cluster:admin/decommission/awareness/put";
+
+    private DecommissionAction() {
+        super(NAME, DecommissionResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequest.java
new file mode 100644
index 0000000000000..18f14db3c2b8d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequest.java
@@ -0,0 +1,154 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Registers a decommission request with decommission attribute and timeout
+ *
+ * @opensearch.internal
+ */
+public class DecommissionRequest extends ClusterManagerNodeRequest<DecommissionRequest> {
+
+    public static final TimeValue DEFAULT_NODE_DRAINING_TIMEOUT = TimeValue.timeValueSeconds(120);
+
+    private DecommissionAttribute decommissionAttribute;
+    private String requestID;
+    private TimeValue delayTimeout = DEFAULT_NODE_DRAINING_TIMEOUT;
+
+    // holder for no_delay param. To avoid draining time timeout.
+    private boolean noDelay = false;
+
+    public DecommissionRequest() {}
+
+    public DecommissionRequest(DecommissionAttribute decommissionAttribute) {
+        this.decommissionAttribute = decommissionAttribute;
+    }
+
+    public DecommissionRequest(StreamInput in) throws IOException {
+        super(in);
+        decommissionAttribute = new DecommissionAttribute(in);
+        this.delayTimeout = in.readTimeValue();
+        this.noDelay = in.readBoolean();
+        this.requestID = in.readOptionalString();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        decommissionAttribute.writeTo(out);
+        out.writeTimeValue(delayTimeout);
+        out.writeBoolean(noDelay);
+        out.writeOptionalString(requestID);
+    }
+
+    /**
+     * Sets decommission attribute for decommission request
+     *
+     * @param decommissionAttribute attribute key-value that needs to be decommissioned
+     * @return this request
+     */
+    public DecommissionRequest setDecommissionAttribute(DecommissionAttribute decommissionAttribute) {
+        this.decommissionAttribute = decommissionAttribute;
+        return this;
+    }
+
+    /**
+     * @return Returns the decommission attribute key-value
+     */
+    public DecommissionAttribute getDecommissionAttribute() {
+        return this.decommissionAttribute;
+    }
+
+    public DecommissionRequest setDelayTimeout(TimeValue delayTimeout) {
+        this.delayTimeout = delayTimeout;
+        return this;
+    }
+
+    public TimeValue getDelayTimeout() {
+        return this.delayTimeout;
+    }
+
+    public DecommissionRequest setNoDelay(boolean noDelay) {
+        if (noDelay) {
+            this.delayTimeout = TimeValue.ZERO;
+        }
+        this.noDelay = noDelay;
+        return this;
+    }
+
+    public boolean isNoDelay() {
+        return noDelay;
+    }
+
+    /**
+     * Sets id for decommission request
+     *
+     * @param requestID uuid for request
+     * @return this request
+     */
+    public DecommissionRequest setRequestID(String requestID) {
+        this.requestID = requestID;
+        return this;
+    }
+
+    /**
+     * @return Returns id of decommission request
+     */
+    public String requestID() {
+        return requestID;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (decommissionAttribute == null) {
+            validationException = addValidationError("decommission attribute is missing", validationException);
+            return validationException;
+        }
+        if (decommissionAttribute.attributeName() == null || Strings.isEmpty(decommissionAttribute.attributeName())) {
+            validationException = addValidationError("attribute name is missing", validationException);
+        }
+        if (decommissionAttribute.attributeValue() == null || Strings.isEmpty(decommissionAttribute.attributeValue())) {
+            validationException = addValidationError("attribute value is missing", validationException);
+        }
+        // This validation should not fail since we are not allowing delay timeout to be set externally.
+        // Still keeping it for double check.
+        if (noDelay && delayTimeout.getSeconds() > 0) {
+            final String validationMessage = "Invalid decommission request. no_delay is true and delay_timeout is set to "
+                + delayTimeout.getSeconds()
+                + "] Seconds";
+            validationException = addValidationError(validationMessage, validationException);
+        }
+        return validationException;
+    }
+
+    @Override
+    public String toString() {
+        return "DecommissionRequest{"
+            + "decommissionAttribute="
+            + decommissionAttribute
+            + ", delayTimeout="
+            + delayTimeout
+            + ", noDelay="
+            + noDelay
+            + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestBuilder.java
new file mode 100644
index 0000000000000..c3591fff54885
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestBuilder.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.action.ActionType;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.common.unit.TimeValue;
+
+/**
+ * Register decommission request builder
+ *
+ * @opensearch.internal
+ */
+public class DecommissionRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
+    DecommissionRequest,
+    DecommissionResponse,
+    DecommissionRequestBuilder> {
+
+    public DecommissionRequestBuilder(OpenSearchClient client, ActionType<DecommissionResponse> action, DecommissionRequest request) {
+        super(client, action, request);
+    }
+
+    /**
+     * @param decommissionAttribute decommission attribute
+     * @return current object
+     */
+    public DecommissionRequestBuilder setDecommissionedAttribute(DecommissionAttribute decommissionAttribute) {
+        request.setDecommissionAttribute(decommissionAttribute);
+        return this;
+    }
+
+    public DecommissionRequestBuilder setDelayTimeOut(TimeValue delayTimeOut) {
+        request.setDelayTimeout(delayTimeOut);
+        return this;
+    }
+
+    public DecommissionRequestBuilder setNoDelay(boolean noDelay) {
+        request.setNoDelay(noDelay);
+        return this;
+    }
+
+    /**
+     * Sets request id for decommission request
+     *
+     * @param requestID for decommission request
+     * @return current object
+     */
+    public DecommissionRequestBuilder requestID(String requestID) {
+        request.setRequestID(requestID);
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponse.java
new file mode 100644
index 0000000000000..13c1775b005b3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponse.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+
+import java.io.IOException;
+
+/**
+ * Response for decommission request
+ *
+ * @opensearch.internal
+ */
+public class DecommissionResponse extends AcknowledgedResponse implements ToXContentObject {
+
+    public DecommissionResponse(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public DecommissionResponse(boolean acknowledged) {
+        super(acknowledged);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/TransportDecommissionAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/TransportDecommissionAction.java
new file mode 100644
index 0000000000000..0b1fd380ffdda
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/TransportDecommissionAction.java
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.decommission.DecommissionService;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for registering decommission
+ *
+ * @opensearch.internal
+ */
+public class TransportDecommissionAction extends TransportClusterManagerNodeAction<DecommissionRequest, DecommissionResponse> {
+
+    private static final Logger logger = LogManager.getLogger(TransportDecommissionAction.class);
+    private final DecommissionService decommissionService;
+
+    @Inject
+    public TransportDecommissionAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        DecommissionService decommissionService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            DecommissionAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            DecommissionRequest::new,
+            indexNameExpressionResolver
+        );
+        this.decommissionService = decommissionService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected DecommissionResponse read(StreamInput in) throws IOException {
+        return new DecommissionResponse(in);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(DecommissionRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+
+    @Override
+    protected void clusterManagerOperation(DecommissionRequest request, ClusterState state, ActionListener<DecommissionResponse> listener)
+        throws Exception {
+        logger.info("starting awareness attribute [{}] decommissioning", request.getDecommissionAttribute().toString());
+        decommissionService.startDecommissionAction(request, listener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/package-info.java
new file mode 100644
index 0000000000000..c361f4b95a484
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/decommission/awareness/put/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handlers for putting a new decommission request */
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthAction.java
index a37c0b0f1cb88..5c712b801f927 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport endpoint action for obtaining cluster health
+ *
+ * @opensearch.internal
+ */
 public class ClusterHealthAction extends ActionType<ClusterHealthResponse> {
 
     public static final ClusterHealthAction INSTANCE = new ClusterHealthAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequest.java
index 204a182edafab..585434db46104 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequest.java
@@ -33,24 +33,33 @@
 package org.opensearch.action.admin.cluster.health;
 
 import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
-public class ClusterHealthRequest extends MasterNodeReadRequest<ClusterHealthRequest> implements IndicesRequest.Replaceable {
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Transport request for requesting cluster health
+ *
+ * @opensearch.internal
+ */
+public class ClusterHealthRequest extends ClusterManagerNodeReadRequest<ClusterHealthRequest> implements IndicesRequest.Replaceable {
 
     private String[] indices;
+    private String awarenessAttribute;
     private IndicesOptions indicesOptions = IndicesOptions.lenientExpandHidden();
     private TimeValue timeout = new TimeValue(30, TimeUnit.SECONDS);
     private ClusterHealthStatus waitForStatus;
@@ -59,6 +68,7 @@ public class ClusterHealthRequest extends MasterNodeReadRequest<ClusterHealthReq
     private ActiveShardCount waitForActiveShards = ActiveShardCount.NONE;
     private String waitForNodes = "";
     private Priority waitForEvents = null;
+    private boolean ensureNodeWeighedIn = false;
     /**
      * Only used by the high-level REST Client. Controls the details level of the health information returned.
      * The default value is 'cluster'.
@@ -90,6 +100,13 @@ public ClusterHealthRequest(StreamInput in) throws IOException {
         } else {
             indicesOptions = IndicesOptions.lenientExpandOpen();
         }
+        if (in.getVersion().onOrAfter(Version.V_2_5_0)) {
+            awarenessAttribute = in.readOptionalString();
+            level = in.readEnum(Level.class);
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_6_0)) {
+            ensureNodeWeighedIn = in.readBoolean();
+        }
     }
 
     @Override
@@ -120,6 +137,13 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_2_0)) {
             indicesOptions.writeIndicesOptions(out);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_5_0)) {
+            out.writeOptionalString(awarenessAttribute);
+            out.writeEnum(level);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_6_0)) {
+            out.writeBoolean(ensureNodeWeighedIn);
+        }
     }
 
     @Override
@@ -154,8 +178,8 @@ public TimeValue timeout() {
 
     public ClusterHealthRequest timeout(TimeValue timeout) {
         this.timeout = timeout;
-        if (masterNodeTimeout == DEFAULT_MASTER_NODE_TIMEOUT) {
-            masterNodeTimeout = timeout;
+        if (clusterManagerNodeTimeout == DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT) {
+            clusterManagerNodeTimeout = timeout;
         }
         return this;
     }
@@ -271,6 +295,22 @@ public void level(Level level) {
         this.level = Objects.requireNonNull(level, "level must not be null");
     }
 
+    public void setLevel(String level) {
+        switch (level) {
+            case "indices":
+                level(ClusterHealthRequest.Level.INDICES);
+                break;
+            case "shards":
+                level(ClusterHealthRequest.Level.SHARDS);
+                break;
+            case "awareness_attributes":
+                level(ClusterHealthRequest.Level.AWARENESS_ATTRIBUTES);
+                break;
+            default:
+                level(ClusterHealthRequest.Level.CLUSTER);
+        }
+    }
+
     /**
      * Get the level of detail for the health information to be returned.
      * Only used by the high-level REST Client.
@@ -279,14 +319,51 @@ public Level level() {
         return level;
     }
 
+    public ClusterHealthRequest setAwarenessAttribute(String awarenessAttribute) {
+        this.awarenessAttribute = awarenessAttribute;
+        return this;
+    }
+
+    public String getAwarenessAttribute() {
+        return awarenessAttribute;
+    }
+
+    public final ClusterHealthRequest ensureNodeWeighedIn(boolean ensureNodeWeighedIn) {
+        this.ensureNodeWeighedIn = ensureNodeWeighedIn;
+        return this;
+    }
+
+    /**
+     * For a given local request, checks if the local node is commissioned or not (default: false).
+     * @return <code>true</code> if local information is to be returned only when local node is also commissioned
+     * <code>false</code> to not check local node if commissioned or not for a local request
+     */
+    public final boolean ensureNodeWeighedIn() {
+        return ensureNodeWeighedIn;
+    }
+
     @Override
     public ActionRequestValidationException validate() {
+        if (level.equals(Level.AWARENESS_ATTRIBUTES) && indices.length > 0) {
+            return addValidationError("awareness_attribute is not a supported parameter with index health", null);
+        } else if (!level.equals(Level.AWARENESS_ATTRIBUTES) && awarenessAttribute != null) {
+            return addValidationError("level=awareness_attributes is required with awareness_attribute parameter", null);
+        }
+        if (ensureNodeWeighedIn && local == false) {
+            return addValidationError("not a local request to ensure local node commissioned or weighed in", null);
+        }
         return null;
     }
 
+    /**
+     * The level of the health request.
+     *
+     * @opensearch.internal
+     */
     public enum Level {
         CLUSTER,
         INDICES,
-        SHARDS
+        SHARDS,
+        AWARENESS_ATTRIBUTES
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestBuilder.java
index 86fee83130bb3..cca9d35d8aa6f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestBuilder.java
@@ -34,13 +34,18 @@
 
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
 import org.opensearch.common.unit.TimeValue;
 
-public class ClusterHealthRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Builder for requesting cluster health
+ *
+ * @opensearch.internal
+ */
+public class ClusterHealthRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     ClusterHealthRequest,
     ClusterHealthResponse,
     ClusterHealthRequestBuilder> {
@@ -146,4 +151,22 @@ public ClusterHealthRequestBuilder setWaitForEvents(Priority waitForEvents) {
         request.waitForEvents(waitForEvents);
         return this;
     }
+
+    public ClusterHealthRequestBuilder setAwarenessAttribute(String awarenessAttribute) {
+        request.setAwarenessAttribute(awarenessAttribute);
+        return this;
+    }
+
+    public ClusterHealthRequestBuilder setLevel(String level) {
+        request.setLevel(level);
+        return this;
+    }
+
+    /**
+     * Specifies if the local request should ensure that the local node is commissioned
+     */
+    public final ClusterHealthRequestBuilder setEnsureNodeWeighedIn(boolean ensureNodeCommissioned) {
+        request.ensureNodeWeighedIn(ensureNodeCommissioned);
+        return this;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponse.java
index d9094e307fff1..fb68012502116 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponse.java
@@ -32,22 +32,26 @@
 
 package org.opensearch.action.admin.cluster.health;
 
-import org.opensearch.action.ActionResponse;
+import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.awarenesshealth.ClusterAwarenessHealth;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.health.ClusterIndexHealth;
 import org.opensearch.cluster.health.ClusterStateHealth;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -57,15 +61,21 @@
 import java.util.Objects;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Transport response for Cluster Health
+ *
+ * @opensearch.internal
+ */
 public class ClusterHealthResponse extends ActionResponse implements StatusToXContentObject {
     private static final String CLUSTER_NAME = "cluster_name";
     private static final String STATUS = "status";
     private static final String TIMED_OUT = "timed_out";
     private static final String NUMBER_OF_NODES = "number_of_nodes";
     private static final String NUMBER_OF_DATA_NODES = "number_of_data_nodes";
+    @Deprecated
     private static final String DISCOVERED_MASTER = "discovered_master";
     private static final String DISCOVERED_CLUSTER_MANAGER = "discovered_cluster_manager";
     private static final String NUMBER_OF_PENDING_TASKS = "number_of_pending_tasks";
@@ -90,7 +100,8 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
             // ClusterStateHealth fields
             int numberOfNodes = (int) parsedObjects[i++];
             int numberOfDataNodes = (int) parsedObjects[i++];
-            boolean hasDiscoveredMaster = (boolean) parsedObjects[i++];
+            boolean hasDiscoveredMaster = Boolean.TRUE.equals(parsedObjects[i++]);
+            boolean hasDiscoveredClusterManager = Boolean.TRUE.equals(parsedObjects[i++]);
             int activeShards = (int) parsedObjects[i++];
             int relocatingShards = (int) parsedObjects[i++];
             int activePrimaryShards = (int) parsedObjects[i++];
@@ -118,7 +129,7 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
                 unassignedShards,
                 numberOfNodes,
                 numberOfDataNodes,
-                hasDiscoveredMaster,
+                hasDiscoveredClusterManager || hasDiscoveredMaster,
                 activeShardsPercent,
                 status,
                 indices
@@ -151,7 +162,8 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
         // ClusterStateHealth fields
         PARSER.declareInt(constructorArg(), new ParseField(NUMBER_OF_NODES));
         PARSER.declareInt(constructorArg(), new ParseField(NUMBER_OF_DATA_NODES));
-        PARSER.declareBoolean(constructorArg(), new ParseField(DISCOVERED_MASTER));
+        PARSER.declareBoolean(optionalConstructorArg(), new ParseField(DISCOVERED_MASTER));
+        PARSER.declareBoolean(optionalConstructorArg(), new ParseField(DISCOVERED_CLUSTER_MANAGER));
         PARSER.declareInt(constructorArg(), new ParseField(ACTIVE_SHARDS));
         PARSER.declareInt(constructorArg(), new ParseField(RELOCATING_SHARDS));
         PARSER.declareInt(constructorArg(), new ParseField(ACTIVE_PRIMARY_SHARDS));
@@ -179,6 +191,7 @@ public class ClusterHealthResponse extends ActionResponse implements StatusToXCo
     private boolean timedOut = false;
     private ClusterStateHealth clusterStateHealth;
     private ClusterHealthStatus clusterHealthStatus;
+    private ClusterAwarenessHealth clusterAwarenessHealth;
 
     public ClusterHealthResponse() {}
 
@@ -192,6 +205,11 @@ public ClusterHealthResponse(StreamInput in) throws IOException {
         numberOfInFlightFetch = in.readInt();
         delayedUnassignedShards = in.readInt();
         taskMaxWaitingTime = in.readTimeValue();
+        if (in.getVersion().onOrAfter(Version.V_2_5_0)) {
+            if (in.readBoolean()) {
+                clusterAwarenessHealth = new ClusterAwarenessHealth(in);
+            }
+        }
     }
 
     /** needed for plugins BWC */
@@ -217,6 +235,30 @@ public ClusterHealthResponse(
         this.clusterHealthStatus = clusterStateHealth.getStatus();
     }
 
+    // Awareness Attribute health
+    public ClusterHealthResponse(
+        String clusterName,
+        ClusterState clusterState,
+        ClusterSettings clusterSettings,
+        String[] concreteIndices,
+        String awarenessAttributeName,
+        int numberOfPendingTasks,
+        int numberOfInFlightFetch,
+        int delayedUnassignedShards,
+        TimeValue taskMaxWaitingTime
+    ) {
+        this(
+            clusterName,
+            concreteIndices,
+            clusterState,
+            numberOfPendingTasks,
+            numberOfInFlightFetch,
+            delayedUnassignedShards,
+            taskMaxWaitingTime
+        );
+        this.clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, awarenessAttributeName);
+    }
+
     /**
      * For XContent Parser and serialization tests
      */
@@ -276,8 +318,14 @@ public int getNumberOfDataNodes() {
         return clusterStateHealth.getNumberOfDataNodes();
     }
 
+    public boolean hasDiscoveredClusterManager() {
+        return clusterStateHealth.hasDiscoveredClusterManager();
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #hasDiscoveredClusterManager()} */
+    @Deprecated
     public boolean hasDiscoveredMaster() {
-        return clusterStateHealth.hasDiscoveredMaster();
+        return hasDiscoveredClusterManager();
     }
 
     public int getNumberOfPendingTasks() {
@@ -343,6 +391,10 @@ public double getActiveShardsPercent() {
         return clusterStateHealth.getActiveShardsPercent();
     }
 
+    public ClusterAwarenessHealth getClusterAwarenessHealth() {
+        return clusterAwarenessHealth;
+    }
+
     public static ClusterHealthResponse readResponseFrom(StreamInput in) throws IOException {
         return new ClusterHealthResponse(in);
     }
@@ -357,11 +409,19 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeInt(numberOfInFlightFetch);
         out.writeInt(delayedUnassignedShards);
         out.writeTimeValue(taskMaxWaitingTime);
+        if (out.getVersion().onOrAfter(Version.V_2_5_0)) {
+            if (clusterAwarenessHealth != null) {
+                out.writeBoolean(true);
+                clusterAwarenessHealth.writeTo(out);
+            } else {
+                out.writeBoolean(false);
+            }
+        }
     }
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
@@ -377,8 +437,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.field(TIMED_OUT, isTimedOut());
         builder.field(NUMBER_OF_NODES, getNumberOfNodes());
         builder.field(NUMBER_OF_DATA_NODES, getNumberOfDataNodes());
-        builder.field(DISCOVERED_MASTER, hasDiscoveredMaster());  // the field will be removed in a future major version
-        builder.field(DISCOVERED_CLUSTER_MANAGER, hasDiscoveredMaster());
+        builder.field(DISCOVERED_MASTER, hasDiscoveredClusterManager());  // the field will be removed in a future major version
+        builder.field(DISCOVERED_CLUSTER_MANAGER, hasDiscoveredClusterManager());
         builder.field(ACTIVE_PRIMARY_SHARDS, getActivePrimaryShards());
         builder.field(ACTIVE_SHARDS, getActiveShards());
         builder.field(RELOCATING_SHARDS, getRelocatingShards());
@@ -392,6 +452,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
         String level = params.param("level", "cluster");
         boolean outputIndices = "indices".equals(level) || "shards".equals(level);
+        boolean outputAwarenessHealth = "awareness_attributes".equals(level);
 
         if (outputIndices) {
             builder.startObject(INDICES);
@@ -400,6 +461,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             }
             builder.endObject();
         }
+
+        if (outputAwarenessHealth && clusterAwarenessHealth != null) {
+            clusterAwarenessHealth.toXContent(builder, params);
+        }
+
         builder.endObject();
         return builder;
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthAction.java
index 6855803ba6c45..1cc357a4c20f4 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthAction.java
@@ -35,28 +35,35 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.LocalClusterUpdateTask;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.coordination.Coordinator;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.NodeWeighedAwayException;
 import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.routing.WeightedRoutingUtils;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.discovery.Discovery;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.tasks.Task;
@@ -67,11 +74,17 @@
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 
-public class TransportClusterHealthAction extends TransportMasterNodeReadAction<ClusterHealthRequest, ClusterHealthResponse> {
+/**
+ * Transport action for obtaining Cluster Health
+ *
+ * @opensearch.internal
+ */
+public class TransportClusterHealthAction extends TransportClusterManagerNodeReadAction<ClusterHealthRequest, ClusterHealthResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportClusterHealthAction.class);
 
     private final AllocationService allocationService;
+    private final Discovery discovery;
 
     @Inject
     public TransportClusterHealthAction(
@@ -80,7 +93,8 @@ public TransportClusterHealthAction(
         ThreadPool threadPool,
         ActionFilters actionFilters,
         IndexNameExpressionResolver indexNameExpressionResolver,
-        AllocationService allocationService
+        AllocationService allocationService,
+        Discovery discovery
     ) {
         super(
             ClusterHealthAction.NAME,
@@ -93,6 +107,7 @@ public TransportClusterHealthAction(
             indexNameExpressionResolver
         );
         this.allocationService = allocationService;
+        this.discovery = discovery;
     }
 
     @Override
@@ -113,19 +128,28 @@ protected ClusterBlockException checkBlock(ClusterHealthRequest request, Cluster
     }
 
     @Override
-    protected final void masterOperation(ClusterHealthRequest request, ClusterState state, ActionListener<ClusterHealthResponse> listener)
-        throws Exception {
+    protected final void clusterManagerOperation(
+        ClusterHealthRequest request,
+        ClusterState state,
+        ActionListener<ClusterHealthResponse> listener
+    ) throws Exception {
         logger.warn("attempt to execute a cluster health operation without a task");
         throw new UnsupportedOperationException("task parameter is required for this operation");
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final Task task,
         final ClusterHealthRequest request,
         final ClusterState unusedState,
         final ActionListener<ClusterHealthResponse> listener
     ) {
+        if (request.ensureNodeWeighedIn()
+            && discovery instanceof Coordinator
+            && ((Coordinator) discovery).localNodeCommissioned() == false) {
+            listener.onFailure(new NodeDecommissionedException("local node is decommissioned"));
+            return;
+        }
 
         final int waitCount = getWaitCount(request);
 
@@ -216,13 +240,14 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                     }
 
                     @Override
-                    public void onNoLongerMaster(String source) {
+                    public void onNoLongerClusterManager(String source) {
                         logger.trace(
-                            "stopped being master while waiting for events with priority [{}]. retrying.",
+                            "stopped being cluster-manager while waiting for events with priority [{}]. retrying.",
                             request.waitForEvents()
                         );
-                        // TransportMasterNodeAction implements the retry logic, which is triggered by passing a NotMasterException
-                        listener.onFailure(new NotMasterException("no longer master. source: [" + source + "]"));
+                        // TransportClusterManagerNodeAction implements the retry logic,
+                        // which is triggered by passing a NotClusterManagerException
+                        listener.onFailure(new NotClusterManagerException("no longer cluster-manager. source: [" + source + "]"));
                     }
 
                     @Override
@@ -254,7 +279,25 @@ private void executeHealth(
 
         final Predicate<ClusterState> validationPredicate = newState -> validateRequest(request, newState, waitCount);
         if (validationPredicate.test(currentState)) {
-            listener.onResponse(getResponse(request, currentState, waitCount, TimeoutState.OK));
+            ClusterHealthResponse clusterHealthResponse = getResponse(request, currentState, waitCount, TimeoutState.OK);
+            if (request.ensureNodeWeighedIn()) {
+                if (clusterHealthResponse.hasDiscoveredClusterManager() == false) {
+                    listener.onFailure(new ClusterManagerNotDiscoveredException("cluster-manager not discovered"));
+                    return;
+                } else {
+                    DiscoveryNode localNode = currentState.getNodes().getLocalNode();
+                    // TODO: make this check more generic, check for node role instead
+                    if (localNode.isDataNode()) {
+                        assert request.local() == true : "local node request false for request for local node weighed in";
+                        boolean weighedAway = WeightedRoutingUtils.isWeighedAway(localNode.getId(), currentState);
+                        if (weighedAway) {
+                            listener.onFailure(new NodeWeighedAwayException("local node is weighed away"));
+                            return;
+                        }
+                    }
+                }
+            }
+            listener.onResponse(clusterHealthResponse);
         } else {
             final ClusterStateObserver observer = new ClusterStateObserver(
                 currentState,
@@ -310,9 +353,9 @@ private boolean validateRequest(final ClusterHealthRequest request, ClusterState
         ClusterHealthResponse response = clusterHealth(
             request,
             clusterState,
-            clusterService.getMasterService().numberOfPendingTasks(),
+            clusterService.getClusterManagerService().numberOfPendingTasks(),
             allocationService.getNumberOfInFlightFetches(),
-            clusterService.getMasterService().getMaxTaskWaitTime()
+            clusterService.getClusterManagerService().getMaxTaskWaitTime()
         );
         return prepareResponse(request, response, clusterState, indexNameExpressionResolver) == waitCount;
     }
@@ -332,9 +375,9 @@ private ClusterHealthResponse getResponse(
         ClusterHealthResponse response = clusterHealth(
             request,
             clusterState,
-            clusterService.getMasterService().numberOfPendingTasks(),
+            clusterService.getClusterManagerService().numberOfPendingTasks(),
             allocationService.getNumberOfInFlightFetches(),
-            clusterService.getMasterService().getMaxTaskWaitTime()
+            clusterService.getClusterManagerService().getMaxTaskWaitTime()
         );
         int readyCounter = prepareResponse(request, response, clusterState, indexNameExpressionResolver);
         boolean valid = (readyCounter == waitFor);
@@ -448,6 +491,22 @@ private ClusterHealthResponse clusterHealth(
         }
 
         String[] concreteIndices;
+        if (request.level().equals(ClusterHealthRequest.Level.AWARENESS_ATTRIBUTES)) {
+            String awarenessAttribute = request.getAwarenessAttribute();
+            concreteIndices = clusterState.getMetadata().getConcreteAllIndices();
+            return new ClusterHealthResponse(
+                clusterState.getClusterName().value(),
+                clusterState,
+                clusterService.getClusterSettings(),
+                concreteIndices,
+                awarenessAttribute,
+                numberOfPendingTasks,
+                numberOfInFlightFetch,
+                UnassignedInfo.getNumberOfDelayedUnassigned(clusterState),
+                pendingTaskTimeInQueue
+            );
+        }
+
         try {
             concreteIndices = indexNameExpressionResolver.concreteIndexNames(clusterState, request);
         } catch (IndexNotFoundException e) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/health/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/health/package-info.java
new file mode 100644
index 0000000000000..7512ea5cdaafb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/health/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Health transport handlers. */
+package org.opensearch.action.admin.cluster.health;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodeHotThreads.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodeHotThreads.java
index 7d873bd22719d..9c33d023f832d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodeHotThreads.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodeHotThreads.java
@@ -34,11 +34,16 @@
 
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport for OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class NodeHotThreads extends BaseNodeResponse {
 
     private String hotThreads;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsAction.java
index 1a09bccf0b34e..64689b2e3bc6d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for requesting OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class NodesHotThreadsAction extends ActionType<NodesHotThreadsResponse> {
 
     public static final NodesHotThreadsAction INSTANCE = new NodesHotThreadsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequest.java
index 5f5c566e7b6d2..39e912a995f35 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequest.java
@@ -33,13 +33,18 @@
 package org.opensearch.action.admin.cluster.node.hotthreads;
 
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Transport request for OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class NodesHotThreadsRequest extends BaseNodesRequest<NodesHotThreadsRequest> {
 
     int threads = 3;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequestBuilder.java
index 54a99de61c854..3639439dd3fb8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Builder class for requesting OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class NodesHotThreadsRequestBuilder extends NodesOperationRequestBuilder<
     NodesHotThreadsRequest,
     NodesHotThreadsResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsResponse.java
index 62c73101eddbb..5af9ce50a4bfe 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/NodesHotThreadsResponse.java
@@ -35,12 +35,17 @@
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport response for OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class NodesHotThreadsResponse extends BaseNodesResponse<NodeHotThreads> {
 
     public NodesHotThreadsResponse(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/TransportNodesHotThreadsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/TransportNodesHotThreadsAction.java
index 4c4519c890d90..942fec7a9f41e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/TransportNodesHotThreadsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/TransportNodesHotThreadsAction.java
@@ -39,8 +39,8 @@
 import org.opensearch.action.support.nodes.TransportNodesAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.monitor.jvm.HotThreads;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -48,6 +48,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport action for OpenSearch Hot Threads
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesHotThreadsAction extends TransportNodesAction<
     NodesHotThreadsRequest,
     NodesHotThreadsResponse,
@@ -107,6 +112,11 @@ protected NodeHotThreads nodeOperation(NodeRequest request) {
         }
     }
 
+    /**
+     * Inner node request
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
 
         NodesHotThreadsRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/package-info.java
new file mode 100644
index 0000000000000..a7e6b7c897fe5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/hotthreads/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Hot threads at node level transport handlers. */
+package org.opensearch.action.admin.cluster.node.hotthreads;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodeInfo.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodeInfo.java
index ddef959e66473..c9016b8bddec7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodeInfo.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodeInfo.java
@@ -38,17 +38,18 @@
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.service.ReportingService;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.ingest.IngestInfo;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.os.OsInfo;
 import org.opensearch.monitor.process.ProcessInfo;
-import org.opensearch.node.ReportingService;
 import org.opensearch.search.aggregations.support.AggregationInfo;
+import org.opensearch.search.pipeline.SearchPipelineInfo;
 import org.opensearch.threadpool.ThreadPoolInfo;
 import org.opensearch.transport.TransportInfo;
 
@@ -58,6 +59,8 @@
 
 /**
  * Node information (static, does not change over time).
+ *
+ * @opensearch.internal
  */
 public class NodeInfo extends BaseNodeResponse {
 
@@ -79,8 +82,8 @@ public class NodeInfo extends BaseNodeResponse {
 
     public NodeInfo(StreamInput in) throws IOException {
         super(in);
-        version = Version.readVersion(in);
-        build = Build.readBuild(in);
+        version = in.readVersion();
+        build = in.readBuild();
         if (in.readBoolean()) {
             totalIndexingBuffer = new ByteSizeValue(in.readLong());
         } else {
@@ -100,6 +103,9 @@ public NodeInfo(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             addInfoIfNonNull(AggregationInfo.class, in.readOptionalWriteable(AggregationInfo::new));
         }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            addInfoIfNonNull(SearchPipelineInfo.class, in.readOptionalWriteable(SearchPipelineInfo::new));
+        }
     }
 
     public NodeInfo(
@@ -116,7 +122,8 @@ public NodeInfo(
         @Nullable PluginsAndModules plugins,
         @Nullable IngestInfo ingest,
         @Nullable AggregationInfo aggsInfo,
-        @Nullable ByteSizeValue totalIndexingBuffer
+        @Nullable ByteSizeValue totalIndexingBuffer,
+        @Nullable SearchPipelineInfo searchPipelineInfo
     ) {
         super(node);
         this.version = version;
@@ -131,6 +138,7 @@ public NodeInfo(
         addInfoIfNonNull(PluginsAndModules.class, plugins);
         addInfoIfNonNull(IngestInfo.class, ingest);
         addInfoIfNonNull(AggregationInfo.class, aggsInfo);
+        addInfoIfNonNull(SearchPipelineInfo.class, searchPipelineInfo);
         this.totalIndexingBuffer = totalIndexingBuffer;
     }
 
@@ -201,7 +209,7 @@ public void writeTo(StreamOutput out) throws IOException {
         } else {
             out.writeVInt(version.id);
         }
-        Build.writeBuild(build, out);
+        out.writeBuild(build);
         if (totalIndexingBuffer == null) {
             out.writeBoolean(false);
         } else {
@@ -225,5 +233,121 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             out.writeOptionalWriteable(getInfo(AggregationInfo.class));
         }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeOptionalWriteable(getInfo(SearchPipelineInfo.class));
+        }
+    }
+
+    public static NodeInfo.Builder builder(Version version, Build build, DiscoveryNode node) {
+        return new Builder(version, build, node);
+    }
+
+    /**
+     * Builder class to accommodate new Info types being added to NodeInfo.
+     */
+    public static class Builder {
+        private final Version version;
+        private final Build build;
+        private final DiscoveryNode node;
+
+        private Builder(Version version, Build build, DiscoveryNode node) {
+            this.version = version;
+            this.build = build;
+            this.node = node;
+        }
+
+        private Settings settings;
+        private OsInfo os;
+        private ProcessInfo process;
+        private JvmInfo jvm;
+        private ThreadPoolInfo threadPool;
+        private TransportInfo transport;
+        private HttpInfo http;
+        private PluginsAndModules plugins;
+        private IngestInfo ingest;
+        private AggregationInfo aggsInfo;
+        private ByteSizeValue totalIndexingBuffer;
+        private SearchPipelineInfo searchPipelineInfo;
+
+        public Builder setSettings(Settings settings) {
+            this.settings = settings;
+            return this;
+        }
+
+        public Builder setOs(OsInfo os) {
+            this.os = os;
+            return this;
+        }
+
+        public Builder setProcess(ProcessInfo process) {
+            this.process = process;
+            return this;
+        }
+
+        public Builder setJvm(JvmInfo jvm) {
+            this.jvm = jvm;
+            return this;
+        }
+
+        public Builder setThreadPool(ThreadPoolInfo threadPool) {
+            this.threadPool = threadPool;
+            return this;
+        }
+
+        public Builder setTransport(TransportInfo transport) {
+            this.transport = transport;
+            return this;
+        }
+
+        public Builder setHttp(HttpInfo http) {
+            this.http = http;
+            return this;
+        }
+
+        public Builder setPlugins(PluginsAndModules plugins) {
+            this.plugins = plugins;
+            return this;
+        }
+
+        public Builder setIngest(IngestInfo ingest) {
+            this.ingest = ingest;
+            return this;
+        }
+
+        public Builder setAggsInfo(AggregationInfo aggsInfo) {
+            this.aggsInfo = aggsInfo;
+            return this;
+        }
+
+        public Builder setTotalIndexingBuffer(ByteSizeValue totalIndexingBuffer) {
+            this.totalIndexingBuffer = totalIndexingBuffer;
+            return this;
+        }
+
+        public Builder setSearchPipelineInfo(SearchPipelineInfo searchPipelineInfo) {
+            this.searchPipelineInfo = searchPipelineInfo;
+            return this;
+        }
+
+        public NodeInfo build() {
+            return new NodeInfo(
+                version,
+                build,
+                node,
+                settings,
+                os,
+                process,
+                jvm,
+                threadPool,
+                transport,
+                http,
+                plugins,
+                ingest,
+                aggsInfo,
+                totalIndexingBuffer,
+                searchPipelineInfo
+            );
+        }
+
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoAction.java
index 6850cbee55412..ea0c9d9d7f3c9 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for OpenSearch Node Information
+ *
+ * @opensearch.internal
+ */
 public class NodesInfoAction extends ActionType<NodesInfoResponse> {
 
     public static final NodesInfoAction INSTANCE = new NodesInfoAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequest.java
index 4024c9b0c12a9..e65027171fbb6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -47,6 +47,8 @@
 
 /**
  * A request to get node (cluster) level information.
+ *
+ * @opensearch.internal
  */
 public class NodesInfoRequest extends BaseNodesRequest<NodesInfoRequest> {
 
@@ -197,7 +199,8 @@ public enum Metric {
         PLUGINS("plugins"),
         INGEST("ingest"),
         AGGREGATIONS("aggregations"),
-        INDICES("indices");
+        INDICES("indices"),
+        SEARCH_PIPELINES("search_pipelines");
 
         private String metricName;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestBuilder.java
index 179239cac5257..76ef75b77a1cf 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.nodes.NodesOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport action for OpenSearch Node Information
+ *
+ * @opensearch.internal
+ */
 public class NodesInfoRequestBuilder extends NodesOperationRequestBuilder<NodesInfoRequest, NodesInfoResponse, NodesInfoRequestBuilder> {
 
     public NodesInfoRequestBuilder(OpenSearchClient client, NodesInfoAction action) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoResponse.java
index a483a2fa1f845..5b4444053a8b7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodesInfoResponse.java
@@ -36,19 +36,19 @@
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.ingest.IngestInfo;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.os.OsInfo;
 import org.opensearch.monitor.process.ProcessInfo;
 import org.opensearch.search.aggregations.support.AggregationInfo;
+import org.opensearch.search.pipeline.SearchPipelineInfo;
 import org.opensearch.threadpool.ThreadPoolInfo;
 import org.opensearch.transport.TransportInfo;
 
@@ -56,6 +56,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Transport response for OpenSearch Node Information
+ *
+ * @opensearch.internal
+ */
 public class NodesInfoResponse extends BaseNodesResponse<NodeInfo> implements ToXContentFragment {
 
     public NodesInfoResponse(StreamInput in) throws IOException {
@@ -142,6 +147,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             if (nodeInfo.getInfo(AggregationInfo.class) != null) {
                 nodeInfo.getInfo(AggregationInfo.class).toXContent(builder, params);
             }
+            if (nodeInfo.getInfo(SearchPipelineInfo.class) != null) {
+                nodeInfo.getInfo(SearchPipelineInfo.class).toXContent(builder, params);
+            }
 
             builder.endObject();
         }
@@ -156,7 +164,7 @@ public String toString() {
             builder.startObject();
             toXContent(builder, EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             return "{ \"error\" : \"" + e.getMessage() + "\"}";
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/PluginsAndModules.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/PluginsAndModules.java
index a51a0ab7b6ea6..13f7211d48e9a 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/PluginsAndModules.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/PluginsAndModules.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.admin.cluster.node.info;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.PluginInfo;
 
 import java.io.IOException;
@@ -46,6 +46,8 @@
 
 /**
  * Information about plugins and modules
+ *
+ * @opensearch.internal
  */
 public class PluginsAndModules implements ReportingService.Info {
     private final List<PluginInfo> plugins;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/TransportNodesInfoAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/TransportNodesInfoAction.java
index 52f53f4c1368e..f38ebe35a52d2 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/TransportNodesInfoAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/TransportNodesInfoAction.java
@@ -38,8 +38,8 @@
 import org.opensearch.action.support.nodes.TransportNodesAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.node.NodeService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -48,6 +48,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Transport action for OpenSearch Node Information
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesInfoAction extends TransportNodesAction<
     NodesInfoRequest,
     NodesInfoResponse,
@@ -112,10 +117,16 @@ protected NodeInfo nodeOperation(NodeInfoRequest nodeRequest) {
             metrics.contains(NodesInfoRequest.Metric.PLUGINS.metricName()),
             metrics.contains(NodesInfoRequest.Metric.INGEST.metricName()),
             metrics.contains(NodesInfoRequest.Metric.AGGREGATIONS.metricName()),
-            metrics.contains(NodesInfoRequest.Metric.INDICES.metricName())
+            metrics.contains(NodesInfoRequest.Metric.INDICES.metricName()),
+            metrics.contains(NodesInfoRequest.Metric.SEARCH_PIPELINES.metricName())
         );
     }
 
+    /**
+     * Inner Node Info Request
+     *
+     * @opensearch.internal
+     */
     public static class NodeInfoRequest extends BaseNodeRequest {
 
         NodesInfoRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/info/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/package-info.java
new file mode 100644
index 0000000000000..4203adc8ed2d6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/info/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node Info transport handlers. */
+package org.opensearch.action.admin.cluster.node.info;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessRequest.java
index c75e020c269eb..e4d9267123862 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessRequest.java
@@ -33,13 +33,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Transport level private response for the transport handler registered under
  * {@value TransportLivenessAction#NAME}
+ *
+ * @opensearch.internal
  */
 public final class LivenessRequest extends ActionRequest {
     public LivenessRequest() {}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessResponse.java
index 1737d868f0afb..c164962cadcdc 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/LivenessResponse.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.action.admin.cluster.node.liveness;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Transport level private response for the transport handler registered under
  * {@value TransportLivenessAction#NAME}
+ *
+ * @opensearch.internal
  */
 public final class LivenessResponse extends ActionResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/TransportLivenessAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/TransportLivenessAction.java
index 83f945ab85557..8a075cbee6e90 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/TransportLivenessAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/TransportLivenessAction.java
@@ -40,6 +40,11 @@
 import org.opensearch.transport.TransportRequestHandler;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Transport action for OpenSearch Node Liveness
+ *
+ * @opensearch.internal
+ */
 public final class TransportLivenessAction implements TransportRequestHandler<LivenessRequest> {
 
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/package-info.java
new file mode 100644
index 0000000000000..97dae1e4a4ef4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/liveness/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node liveness transport handlers. */
+package org.opensearch.action.admin.cluster.node.liveness;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/package-info.java
new file mode 100644
index 0000000000000..f92091587eb04
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node level transport handlers. */
+package org.opensearch.action.admin.cluster.node;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsAction.java
index 252c4491bc56c..0f7c847582349 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for reloading OpenSearch Secure Settings
+ *
+ * @opensearch.internal
+ */
 public class NodesReloadSecureSettingsAction extends ActionType<NodesReloadSecureSettingsResponse> {
 
     public static final NodesReloadSecureSettingsAction INSTANCE = new NodesReloadSecureSettingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequest.java
index 5a6c4c2ae7c83..415331a1b33bd 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequest.java
@@ -34,21 +34,21 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-
-import java.io.IOException;
-
 import org.opensearch.common.CharArrays;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.settings.SecureString;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.settings.SecureString;
 
+import java.io.IOException;
 import java.util.Arrays;
 
 /**
  * Request for a reload secure settings action
+ *
+ * @opensearch.internal
  */
 public class NodesReloadSecureSettingsRequest extends BaseNodesRequest<NodesReloadSecureSettingsRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequestBuilder.java
index 8bb67f5042893..2f2162947aeea 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsRequestBuilder.java
@@ -34,10 +34,12 @@
 
 import org.opensearch.action.support.nodes.NodesOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.settings.SecureString;
+import org.opensearch.core.common.settings.SecureString;
 
 /**
  * Builder for the reload secure settings nodes request
+ *
+ * @opensearch.internal
  */
 public class NodesReloadSecureSettingsRequestBuilder extends NodesOperationRequestBuilder<
     NodesReloadSecureSettingsRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsResponse.java
index 9dd8596b86260..6c250a8daaf3e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/NodesReloadSecureSettingsResponse.java
@@ -38,17 +38,19 @@
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
 import java.io.IOException;
 import java.util.List;
 
 /**
  * The response for the reload secure settings action
+ *
+ * @opensearch.internal
  */
 public class NodesReloadSecureSettingsResponse extends BaseNodesResponse<NodesReloadSecureSettingsResponse.NodeResponse>
     implements
@@ -97,12 +99,17 @@ public String toString() {
             builder.startObject();
             toXContent(builder, EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (final IOException e) {
             return "{ \"error\" : \"" + e.getMessage() + "\"}";
         }
     }
 
+    /**
+     * Inner Node Response
+     *
+     * @opensearch.internal
+     */
     public static class NodeResponse extends BaseNodeResponse {
 
         private Exception reloadException = null;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/TransportNodesReloadSecureSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/TransportNodesReloadSecureSettingsAction.java
index e51ba62c804d7..467636ce922e9 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/TransportNodesReloadSecureSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/TransportNodesReloadSecureSettingsAction.java
@@ -34,9 +34,8 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.nodes.BaseNodeRequest;
@@ -44,11 +43,12 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.KeyStoreWrapper;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.plugins.ReloadablePlugin;
@@ -60,6 +60,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Transport action for reloading OpenSearch Secure Settings
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesReloadSecureSettingsAction extends TransportNodesAction<
     NodesReloadSecureSettingsRequest,
     NodesReloadSecureSettingsResponse,
@@ -178,6 +183,11 @@ protected NodesReloadSecureSettingsResponse.NodeResponse nodeOperation(NodeReque
         }
     }
 
+    /**
+     * Inner Node Request
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
 
         NodesReloadSecureSettingsRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/package-info.java
new file mode 100644
index 0000000000000..a2ddf57796a4a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/reload/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node reloading secured settings transport handlers. */
+package org.opensearch.action.admin.cluster.node.reload;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodeStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodeStats.java
index dd2c649e07c28..ce8033e971b44 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodeStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodeStats.java
@@ -37,17 +37,20 @@
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.routing.WeightedRoutingStats;
+import org.opensearch.cluster.service.ClusterManagerThrottlingStats;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.indices.breaker.AllCircuitBreakerStats;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.discovery.DiscoveryStats;
 import org.opensearch.http.HttpStats;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.index.stats.ShardIndexingPressureStats;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.indices.NodeIndicesStats;
-import org.opensearch.indices.breaker.AllCircuitBreakerStats;
 import org.opensearch.ingest.IngestStats;
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.monitor.jvm.JvmStats;
@@ -56,6 +59,9 @@
 import org.opensearch.node.AdaptiveSelectionStats;
 import org.opensearch.script.ScriptCacheStats;
 import org.opensearch.script.ScriptStats;
+import org.opensearch.search.backpressure.stats.SearchBackpressureStats;
+import org.opensearch.search.pipeline.SearchPipelineStats;
+import org.opensearch.tasks.TaskCancellationStats;
 import org.opensearch.threadpool.ThreadPoolStats;
 import org.opensearch.transport.TransportStats;
 
@@ -64,6 +70,8 @@
 
 /**
  * Node statistics (dynamic, changes depending on when created).
+ *
+ * @opensearch.internal
  */
 public class NodeStats extends BaseNodeResponse implements ToXContentFragment {
 
@@ -117,6 +125,24 @@ public class NodeStats extends BaseNodeResponse implements ToXContentFragment {
     @Nullable
     private ShardIndexingPressureStats shardIndexingPressureStats;
 
+    @Nullable
+    private SearchBackpressureStats searchBackpressureStats;
+
+    @Nullable
+    private ClusterManagerThrottlingStats clusterManagerThrottlingStats;
+
+    @Nullable
+    private WeightedRoutingStats weightedRoutingStats;
+
+    @Nullable
+    private FileCacheStats fileCacheStats;
+
+    @Nullable
+    private TaskCancellationStats taskCancellationStats;
+
+    @Nullable
+    private SearchPipelineStats searchPipelineStats;
+
     public NodeStats(StreamInput in) throws IOException {
         super(in);
         timestamp = in.readVLong();
@@ -154,6 +180,37 @@ public NodeStats(StreamInput in) throws IOException {
             shardIndexingPressureStats = null;
         }
 
+        if (in.getVersion().onOrAfter(Version.V_2_4_0)) {
+            searchBackpressureStats = in.readOptionalWriteable(SearchBackpressureStats::new);
+        } else {
+            searchBackpressureStats = null;
+        }
+
+        if (in.getVersion().onOrAfter(Version.V_2_6_0)) {
+            clusterManagerThrottlingStats = in.readOptionalWriteable(ClusterManagerThrottlingStats::new);
+        } else {
+            clusterManagerThrottlingStats = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_6_0)) {
+            weightedRoutingStats = in.readOptionalWriteable(WeightedRoutingStats::new);
+        } else {
+            weightedRoutingStats = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            fileCacheStats = in.readOptionalWriteable(FileCacheStats::new);
+        } else {
+            fileCacheStats = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+            taskCancellationStats = in.readOptionalWriteable(TaskCancellationStats::new);
+        } else {
+            taskCancellationStats = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+            searchPipelineStats = in.readOptionalWriteable(SearchPipelineStats::new);
+        } else {
+            searchPipelineStats = null;
+        }
     }
 
     public NodeStats(
@@ -174,7 +231,13 @@ public NodeStats(
         @Nullable AdaptiveSelectionStats adaptiveSelectionStats,
         @Nullable ScriptCacheStats scriptCacheStats,
         @Nullable IndexingPressureStats indexingPressureStats,
-        @Nullable ShardIndexingPressureStats shardIndexingPressureStats
+        @Nullable ShardIndexingPressureStats shardIndexingPressureStats,
+        @Nullable SearchBackpressureStats searchBackpressureStats,
+        @Nullable ClusterManagerThrottlingStats clusterManagerThrottlingStats,
+        @Nullable WeightedRoutingStats weightedRoutingStats,
+        @Nullable FileCacheStats fileCacheStats,
+        @Nullable TaskCancellationStats taskCancellationStats,
+        @Nullable SearchPipelineStats searchPipelineStats
     ) {
         super(node);
         this.timestamp = timestamp;
@@ -194,6 +257,12 @@ public NodeStats(
         this.scriptCacheStats = scriptCacheStats;
         this.indexingPressureStats = indexingPressureStats;
         this.shardIndexingPressureStats = shardIndexingPressureStats;
+        this.searchBackpressureStats = searchBackpressureStats;
+        this.clusterManagerThrottlingStats = clusterManagerThrottlingStats;
+        this.weightedRoutingStats = weightedRoutingStats;
+        this.fileCacheStats = fileCacheStats;
+        this.taskCancellationStats = taskCancellationStats;
+        this.searchPipelineStats = searchPipelineStats;
     }
 
     public long getTimestamp() {
@@ -303,6 +372,34 @@ public ShardIndexingPressureStats getShardIndexingPressureStats() {
         return shardIndexingPressureStats;
     }
 
+    @Nullable
+    public SearchBackpressureStats getSearchBackpressureStats() {
+        return searchBackpressureStats;
+    }
+
+    @Nullable
+    public ClusterManagerThrottlingStats getClusterManagerThrottlingStats() {
+        return clusterManagerThrottlingStats;
+    }
+
+    public WeightedRoutingStats getWeightedRoutingStats() {
+        return weightedRoutingStats;
+    }
+
+    public FileCacheStats getFileCacheStats() {
+        return fileCacheStats;
+    }
+
+    @Nullable
+    public TaskCancellationStats getTaskCancellationStats() {
+        return taskCancellationStats;
+    }
+
+    @Nullable
+    public SearchPipelineStats getSearchPipelineStats() {
+        return searchPipelineStats;
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
@@ -334,6 +431,24 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(Version.V_1_2_0)) {
             out.writeOptionalWriteable(shardIndexingPressureStats);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_4_0)) {
+            out.writeOptionalWriteable(searchBackpressureStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_6_0)) {
+            out.writeOptionalWriteable(clusterManagerThrottlingStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_6_0)) {
+            out.writeOptionalWriteable(weightedRoutingStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeOptionalWriteable(fileCacheStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+            out.writeOptionalWriteable(taskCancellationStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+            out.writeOptionalWriteable(searchPipelineStats);
+        }
     }
 
     @Override
@@ -406,6 +521,25 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         if (getShardIndexingPressureStats() != null) {
             getShardIndexingPressureStats().toXContent(builder, params);
         }
+        if (getSearchBackpressureStats() != null) {
+            getSearchBackpressureStats().toXContent(builder, params);
+        }
+        if (getClusterManagerThrottlingStats() != null) {
+            getClusterManagerThrottlingStats().toXContent(builder, params);
+        }
+        if (getWeightedRoutingStats() != null) {
+            getWeightedRoutingStats().toXContent(builder, params);
+        }
+        if (getFileCacheStats() != null) {
+            getFileCacheStats().toXContent(builder, params);
+        }
+        if (getTaskCancellationStats() != null) {
+            getTaskCancellationStats().toXContent(builder, params);
+        }
+        if (getSearchPipelineStats() != null) {
+            getSearchPipelineStats().toXContent(builder, params);
+        }
+
         return builder;
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsAction.java
index 77bb141966651..fc039778f05af 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for obtaining OpenSearch Node Stats
+ *
+ * @opensearch.internal
+ */
 public class NodesStatsAction extends ActionType<NodesStatsResponse> {
 
     public static final NodesStatsAction INSTANCE = new NodesStatsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequest.java
index 2ebf2ca424c27..5022427628647 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequest.java
@@ -35,8 +35,9 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -47,6 +48,8 @@
 
 /**
  * A request to get node (cluster) level stats.
+ *
+ * @opensearch.internal
  */
 public class NodesStatsRequest extends BaseNodesRequest<NodesStatsRequest> {
 
@@ -235,7 +238,13 @@ public enum Metric {
         ADAPTIVE_SELECTION("adaptive_selection"),
         SCRIPT_CACHE("script_cache"),
         INDEXING_PRESSURE("indexing_pressure"),
-        SHARD_INDEXING_PRESSURE("shard_indexing_pressure");
+        SHARD_INDEXING_PRESSURE("shard_indexing_pressure"),
+        SEARCH_BACKPRESSURE("search_backpressure"),
+        CLUSTER_MANAGER_THROTTLING("cluster_manager_throttling"),
+        WEIGHTED_ROUTING_STATS("weighted_routing"),
+        FILE_CACHE_STATS("file_cache"),
+        TASK_CANCELLATION("task_cancellation"),
+        SEARCH_PIPELINE("search_pipeline");
 
         private String metricName;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestBuilder.java
index 40d6946823727..e382278f5ddb8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.action.support.nodes.NodesOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport builder for obtaining OpenSearch Node Stats
+ *
+ * @opensearch.internal
+ */
 public class NodesStatsRequestBuilder extends NodesOperationRequestBuilder<
     NodesStatsRequest,
     NodesStatsResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsResponse.java
index 8c84775e356c4..8fbc52ad8a3f8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsResponse.java
@@ -35,16 +35,20 @@
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport response for obtaining OpenSearch Node Stats
+ *
+ * @opensearch.internal
+ */
 public class NodesStatsResponse extends BaseNodesResponse<NodeStats> implements ToXContentFragment {
 
     public NodesStatsResponse(StreamInput in) throws IOException {
@@ -87,7 +91,7 @@ public String toString() {
             builder.startObject();
             toXContent(builder, EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             return "{ \"error\" : \"" + e.getMessage() + "\"}";
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/TransportNodesStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/TransportNodesStatsAction.java
index b7ea714de4eb4..2c1a61ea6e3b2 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/TransportNodesStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/TransportNodesStatsAction.java
@@ -38,8 +38,8 @@
 import org.opensearch.action.support.nodes.TransportNodesAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.node.NodeService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -48,6 +48,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Transport action for obtaining OpenSearch Node Stats
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesStatsAction extends TransportNodesAction<
     NodesStatsRequest,
     NodesStatsResponse,
@@ -113,10 +118,21 @@ protected NodeStats nodeOperation(NodeStatsRequest nodeStatsRequest) {
             NodesStatsRequest.Metric.ADAPTIVE_SELECTION.containedIn(metrics),
             NodesStatsRequest.Metric.SCRIPT_CACHE.containedIn(metrics),
             NodesStatsRequest.Metric.INDEXING_PRESSURE.containedIn(metrics),
-            NodesStatsRequest.Metric.SHARD_INDEXING_PRESSURE.containedIn(metrics)
+            NodesStatsRequest.Metric.SHARD_INDEXING_PRESSURE.containedIn(metrics),
+            NodesStatsRequest.Metric.SEARCH_BACKPRESSURE.containedIn(metrics),
+            NodesStatsRequest.Metric.CLUSTER_MANAGER_THROTTLING.containedIn(metrics),
+            NodesStatsRequest.Metric.WEIGHTED_ROUTING_STATS.containedIn(metrics),
+            NodesStatsRequest.Metric.FILE_CACHE_STATS.containedIn(metrics),
+            NodesStatsRequest.Metric.TASK_CANCELLATION.containedIn(metrics),
+            NodesStatsRequest.Metric.SEARCH_PIPELINE.containedIn(metrics)
         );
     }
 
+    /**
+     * Inner Node Stats Request
+     *
+     * @opensearch.internal
+     */
     public static class NodeStatsRequest extends BaseNodeRequest {
 
         NodesStatsRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/package-info.java
new file mode 100644
index 0000000000000..14efa77f066d6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node Stats transport handlers. */
+package org.opensearch.action.admin.cluster.node.stats;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksAction.java
index 6d6098adaa92c..d4f6dc39c93f7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksAction.java
@@ -36,6 +36,8 @@
 
 /**
  * ActionType for cancelling running tasks
+ *
+ * @opensearch.internal
  */
 public class CancelTasksAction extends ActionType<CancelTasksResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequest.java
index ea7e225051b80..8d2e1ac5eca42 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.support.tasks.BaseTasksRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
 
@@ -44,6 +44,8 @@
 
 /**
  * A request to cancel tasks
+ *
+ * @opensearch.internal
  */
 public class CancelTasksRequest extends BaseTasksRequest<CancelTasksRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestBuilder.java
index c0686f166c859..ee19e8b104603 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestBuilder.java
@@ -37,6 +37,8 @@
 
 /**
  * Builder for the request to cancel tasks running on the specified nodes
+ *
+ * @opensearch.internal
  */
 public class CancelTasksRequestBuilder extends TasksRequestBuilder<CancelTasksRequest, CancelTasksResponse, CancelTasksRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksResponse.java
index 056463b85fe80..979489999cc6e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksResponse.java
@@ -35,11 +35,12 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
@@ -47,6 +48,8 @@
 
 /**
  * Returns the list of tasks that were cancelled
+ *
+ * @opensearch.internal
  */
 public class CancelTasksResponse extends ListTasksResponse {
 
@@ -78,6 +81,6 @@ public static CancelTasksResponse fromXContent(XContentParser parser) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/TransportCancelTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/TransportCancelTasksAction.java
index 963ebe24ae8e2..634ce1e2d4095 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/TransportCancelTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/TransportCancelTasksAction.java
@@ -33,13 +33,13 @@
 package org.opensearch.action.admin.cluster.node.tasks.cancel;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.tasks.TransportTasksAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.threadpool.ThreadPool;
@@ -54,6 +54,8 @@
  * <p>
  * For a task to be cancellable it has to return an instance of
  * {@link CancellableTask} from {@link TransportRequest#createTask}
+ *
+ * @opensearch.internal
  */
 public class TransportCancelTasksAction extends TransportTasksAction<CancellableTask, CancelTasksRequest, CancelTasksResponse, TaskInfo> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/package-info.java
new file mode 100644
index 0000000000000..898aa26d16792
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/cancel/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler for Cancelling Node Tasks */
+package org.opensearch.action.admin.cluster.node.tasks.cancel;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskAction.java
index 4297e911d6bde..3b429d61c31b3 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskAction.java
@@ -36,6 +36,8 @@
 
 /**
  * ActionType for retrieving a list of currently running tasks
+ *
+ * @opensearch.internal
  */
 public class GetTaskAction extends ActionType<GetTaskResponse> {
     public static final String TASKS_ORIGIN = "tasks";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequest.java
index a8fee2dc22d30..82902c55b1b0a 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequest.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 
 import java.io.IOException;
 
@@ -45,6 +45,8 @@
 
 /**
  * A request to get node tasks
+ *
+ * @opensearch.internal
  */
 public class GetTaskRequest extends ActionRequest {
     private TaskId taskId = TaskId.EMPTY_TASK_ID;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequestBuilder.java
index d7d0be125bee3..dd429da82ebf8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskRequestBuilder.java
@@ -35,10 +35,12 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 
 /**
  * Builder for the request to retrieve the list of tasks running on the specified nodes
+ *
+ * @opensearch.internal
  */
 public class GetTaskRequestBuilder extends ActionRequestBuilder<GetTaskRequest, GetTaskResponse> {
     public GetTaskRequestBuilder(OpenSearchClient client, GetTaskAction action) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskResponse.java
index 32d7062449a71..9d4e6da8c7e62 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/GetTaskResponse.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.action.admin.cluster.node.tasks.get;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.TaskResult;
 
 import java.io.IOException;
@@ -46,6 +47,8 @@
 
 /**
  * Returns the list of tasks currently running on the nodes
+ *
+ * @opensearch.internal
  */
 public class GetTaskResponse extends ActionResponse implements ToXContentObject {
 
@@ -82,6 +85,6 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/TransportGetTaskAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/TransportGetTaskAction.java
index 80049b5e30fdf..8d82827f4ee50 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/TransportGetTaskAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/TransportGetTaskAction.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.action.admin.cluster.node.tasks.get;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
@@ -48,12 +47,13 @@
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.tasks.TaskResult;
 import org.opensearch.tasks.TaskResultsService;
@@ -74,6 +74,8 @@
  * <li>Look up the task and return it if it exists
  * <li>If it doesn't then look up the task from the results index
  * </ul>
+ *
+ * @opensearch.internal
  */
 public class TransportGetTaskAction extends HandledTransportAction<GetTaskRequest, GetTaskResponse> {
     private final ThreadPool threadPool;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/package-info.java
new file mode 100644
index 0000000000000..0eb044c2a29eb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handlers for getting Node Tasks. */
+package org.opensearch.action.admin.cluster.node.tasks.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksAction.java
index 76c07cd570622..7c8b83ad9c913 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksAction.java
@@ -36,6 +36,8 @@
 
 /**
  * ActionType for retrieving a list of currently running tasks
+ *
+ * @opensearch.internal
  */
 public class ListTasksAction extends ActionType<ListTasksResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequest.java
index 4f1a5765d1eea..070b93c788ef0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequest.java
@@ -33,13 +33,15 @@
 package org.opensearch.action.admin.cluster.node.tasks.list;
 
 import org.opensearch.action.support.tasks.BaseTasksRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * A request to get node tasks
+ *
+ * @opensearch.internal
  */
 public class ListTasksRequest extends BaseTasksRequest<ListTasksRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequestBuilder.java
index dc10fb99e90b9..45beb0dd899b5 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksRequestBuilder.java
@@ -37,6 +37,8 @@
 
 /**
  * Builder for the request to retrieve the list of tasks running on the specified nodes
+ *
+ * @opensearch.internal
  */
 public class ListTasksRequestBuilder extends TasksRequestBuilder<ListTasksRequest, ListTasksResponse, ListTasksRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java
index db0b1491fd693..693566391fb25 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java
@@ -38,16 +38,17 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
@@ -58,10 +59,12 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Returns the list of tasks currently running on the nodes
+ *
+ * @opensearch.internal
  */
 public class ListTasksResponse extends BaseTasksResponse implements ToXContentObject {
     private static final String TASKS = "tasks";
@@ -259,6 +262,6 @@ public static ListTasksResponse fromXContent(XContentParser parser) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TaskGroup.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TaskGroup.java
index 6d1d96bfd7869..0ca114ae0ed5c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TaskGroup.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TaskGroup.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.node.tasks.list;
 
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
@@ -44,6 +44,8 @@
 
 /**
  * Information about a currently running task and all its subtasks.
+ *
+ * @opensearch.internal
  */
 public class TaskGroup implements ToXContentObject {
 
@@ -60,6 +62,11 @@ public static Builder builder(TaskInfo taskInfo) {
         return new Builder(taskInfo);
     }
 
+    /**
+     * Builder for the Task Group
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private TaskInfo taskInfo;
         private List<Builder> childTasks;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TransportListTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TransportListTasksAction.java
index b7875c5f99774..1c543e60c46e0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TransportListTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/TransportListTasksAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.cluster.node.tasks.list;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.support.ActionFilters;
@@ -40,8 +39,10 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskInfo;
+import org.opensearch.tasks.TaskResourceTrackingService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -50,6 +51,11 @@
 
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 
+/**
+ * Transport action for listing tasks currently running on the nodes
+ *
+ * @opensearch.internal
+ */
 public class TransportListTasksAction extends TransportTasksAction<Task, ListTasksRequest, ListTasksResponse, TaskInfo> {
     public static long waitForCompletionTimeout(TimeValue timeout) {
         if (timeout == null) {
@@ -60,8 +66,15 @@ public static long waitForCompletionTimeout(TimeValue timeout) {
 
     private static final TimeValue DEFAULT_WAIT_FOR_COMPLETION_TIMEOUT = timeValueSeconds(30);
 
+    private final TaskResourceTrackingService taskResourceTrackingService;
+
     @Inject
-    public TransportListTasksAction(ClusterService clusterService, TransportService transportService, ActionFilters actionFilters) {
+    public TransportListTasksAction(
+        ClusterService clusterService,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        TaskResourceTrackingService taskResourceTrackingService
+    ) {
         super(
             ListTasksAction.NAME,
             clusterService,
@@ -72,6 +85,7 @@ public TransportListTasksAction(ClusterService clusterService, TransportService
             TaskInfo::new,
             ThreadPool.Names.MANAGEMENT
         );
+        this.taskResourceTrackingService = taskResourceTrackingService;
     }
 
     @Override
@@ -101,6 +115,8 @@ protected void processTasks(ListTasksRequest request, Consumer<Task> operation)
                 }
                 taskManager.waitForTaskCompletion(task, timeoutNanos);
             });
+        } else {
+            operation = operation.andThen(taskResourceTrackingService::refreshResourceStats);
         }
         super.processTasks(request, operation);
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/package-info.java
new file mode 100644
index 0000000000000..df84d7fe19d02
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/list/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handlers for listing node tasks. */
+package org.opensearch.action.admin.cluster.node.tasks.list;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/package-info.java
new file mode 100644
index 0000000000000..9d809646460f2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/tasks/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node tasks transport handlers. */
+package org.opensearch.action.admin.cluster.node.tasks;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodeUsage.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodeUsage.java
index 2094861185b50..8170d3631d029 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodeUsage.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodeUsage.java
@@ -35,14 +35,19 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Concrete class for collecting OpenSearch telemetry
+ *
+ * @opensearch.internal
+ */
 public class NodeUsage extends BaseNodeResponse implements ToXContentFragment {
 
     private final long timestamp;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageAction.java
index 2a3c6be6e0bbe..8a3aec7679709 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for collecting OpenSearch telemetry
+ *
+ * @opensearch.internal
+ */
 public class NodesUsageAction extends ActionType<NodesUsageResponse> {
 
     public static final NodesUsageAction INSTANCE = new NodesUsageAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequest.java
index 0a94f2a9bfca7..d1845861fc4e8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequest.java
@@ -34,11 +34,16 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for collecting OpenSearch telemetry
+ *
+ * @opensearch.internal
+ */
 public class NodesUsageRequest extends BaseNodesRequest<NodesUsageRequest> {
 
     private boolean restActions;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequestBuilder.java
index fefccf4368230..7d1823b59dc04 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.action.support.nodes.NodesOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport builder for collecting OpenSearch telemetry
+ *
+ * @opensearch.internal
+ */
 public class NodesUsageRequestBuilder extends NodesOperationRequestBuilder<
     NodesUsageRequest,
     NodesUsageResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageResponse.java
index d3e5aeea72193..575d88c10317c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/NodesUsageResponse.java
@@ -35,12 +35,11 @@
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -48,6 +47,8 @@
 /**
  * The response for the nodes usage api which contains the individual usage
  * statistics for all nodes queried.
+ *
+ * @opensearch.internal
  */
 public class NodesUsageResponse extends BaseNodesResponse<NodeUsage> implements ToXContentFragment {
 
@@ -91,7 +92,7 @@ public String toString() {
             builder.startObject();
             toXContent(builder, EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             return "{ \"error\" : \"" + e.getMessage() + "\"}";
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/TransportNodesUsageAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/TransportNodesUsageAction.java
index 207a5eb41c85d..091d99da3424a 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/TransportNodesUsageAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/TransportNodesUsageAction.java
@@ -38,8 +38,8 @@
 import org.opensearch.action.support.nodes.TransportNodesAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.aggregations.support.AggregationUsageService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -49,6 +49,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Transport action for collecting OpenSearch telemetry
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesUsageAction extends TransportNodesAction<
     NodesUsageRequest,
     NodesUsageResponse,
@@ -107,6 +112,11 @@ protected NodeUsage nodeOperation(NodeUsageRequest nodeUsageRequest) {
         return new NodeUsage(clusterService.localNode(), System.currentTimeMillis(), sinceTime, restUsage, aggsUsage);
     }
 
+    /**
+     * Inner Node Usage Request
+     *
+     * @opensearch.internal
+     */
     public static class NodeUsageRequest extends BaseNodeRequest {
 
         NodesUsageRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/package-info.java
new file mode 100644
index 0000000000000..37943b23dbe10
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/node/usage/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node Usage transport handlers. */
+package org.opensearch.action.admin.cluster.node.usage;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoAction.java
index 099b3abc7438c..55f75a142a53c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for remote monitoring
+ *
+ * @opensearch.internal
+ */
 public final class RemoteInfoAction extends ActionType<RemoteInfoResponse> {
 
     public static final String NAME = "cluster:monitor/remote/info";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequest.java
index c140a639ac3ae..be219b15875df 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequest.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for remote monitoring
+ *
+ * @opensearch.internal
+ */
 public final class RemoteInfoRequest extends ActionRequest {
 
     public RemoteInfoRequest() {}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequestBuilder.java
index 5fceced383731..03fd2a3f778ec 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport builder for remote monitoring
+ *
+ * @opensearch.internal
+ */
 public final class RemoteInfoRequestBuilder extends ActionRequestBuilder<RemoteInfoRequest, RemoteInfoResponse> {
 
     public RemoteInfoRequestBuilder(OpenSearchClient client, RemoteInfoAction action) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoResponse.java
index 415e71e6d1010..2f47de4f6a5fe 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/RemoteInfoResponse.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.action.admin.cluster.remote;
 
-import org.opensearch.action.ActionResponse;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.transport.RemoteConnectionInfo;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -45,6 +45,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Transport response for remote monitoring
+ *
+ * @opensearch.internal
+ */
 public final class RemoteInfoResponse extends ActionResponse implements ToXContentObject {
 
     private List<RemoteConnectionInfo> infos;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/TransportRemoteInfoAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/TransportRemoteInfoAction.java
index 10b1917b0c94b..cb7c965069987 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/remote/TransportRemoteInfoAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/TransportRemoteInfoAction.java
@@ -32,17 +32,22 @@
 
 package org.opensearch.action.admin.cluster.remote;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.SearchTransportService;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.RemoteClusterService;
 import org.opensearch.transport.TransportService;
 
 import static java.util.stream.Collectors.toList;
 
+/**
+ * Transport action for remote monitoring
+ *
+ * @opensearch.internal
+ */
 public final class TransportRemoteInfoAction extends HandledTransportAction<RemoteInfoRequest, RemoteInfoResponse> {
 
     private final RemoteClusterService remoteClusterService;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remote/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/remote/package-info.java
new file mode 100644
index 0000000000000..e5be56ff1d139
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remote/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Remote Node Information transport handlers. */
+package org.opensearch.action.admin.cluster.remote;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreAction.java
new file mode 100644
index 0000000000000..46b1bc14e8537
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Restore remote store action
+ *
+ * @opensearch.internal
+ */
+public final class RestoreRemoteStoreAction extends ActionType<RestoreRemoteStoreResponse> {
+
+    public static final RestoreRemoteStoreAction INSTANCE = new RestoreRemoteStoreAction();
+    public static final String NAME = "cluster:admin/remotestore/restore";
+
+    private RestoreRemoteStoreAction() {
+        super(NAME, RestoreRemoteStoreResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequest.java
new file mode 100644
index 0000000000000..6b3d04c639bc9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequest.java
@@ -0,0 +1,211 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Restore remote store request
+ *
+ * @opensearch.internal
+ */
+public class RestoreRemoteStoreRequest extends ClusterManagerNodeRequest<RestoreRemoteStoreRequest> implements ToXContentObject {
+
+    private String[] indices = Strings.EMPTY_ARRAY;
+    private Boolean waitForCompletion = false;
+    private Boolean restoreAllShards = false;
+
+    public RestoreRemoteStoreRequest() {}
+
+    public RestoreRemoteStoreRequest(StreamInput in) throws IOException {
+        super(in);
+        indices = in.readStringArray();
+        waitForCompletion = in.readOptionalBoolean();
+        restoreAllShards = in.readOptionalBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(indices);
+        out.writeOptionalBoolean(waitForCompletion);
+        out.writeOptionalBoolean(restoreAllShards);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (indices == null || indices.length == 0) {
+            validationException = addValidationError("indices are missing", validationException);
+        }
+        return validationException;
+    }
+
+    /**
+     * Sets the list of indices that should be restored from the remote store
+     * <p>
+     * The list of indices supports multi-index syntax. For example: "+test*" ,"-test42" will index all indices with
+     * prefix "test" except index "test42". Aliases are not supported. An empty list or {"_all"} will restore all open
+     * indices in the cluster.
+     *
+     * @param indices list of indices
+     * @return this request
+     */
+    public RestoreRemoteStoreRequest indices(String... indices) {
+        this.indices = indices;
+        return this;
+    }
+
+    /**
+     * Sets the list of indices that should be restored from the remote store
+     * <p>
+     * The list of indices supports multi-index syntax. For example: "+test*" ,"-test42" will index all indices with
+     * prefix "test" except index "test42". Aliases are not supported. An empty list or {"_all"} will restore all open
+     * indices in the cluster.
+     *
+     * @param indices list of indices
+     * @return this request
+     */
+    public RestoreRemoteStoreRequest indices(List<String> indices) {
+        this.indices = indices.toArray(new String[indices.size()]);
+        return this;
+    }
+
+    /**
+     * Returns list of indices that should be restored from the remote store
+     */
+    public String[] indices() {
+        return indices;
+    }
+
+    /**
+     * If this parameter is set to true the operation will wait for completion of restore process before returning.
+     *
+     * @param waitForCompletion if true the operation will wait for completion
+     * @return this request
+     */
+    public RestoreRemoteStoreRequest waitForCompletion(boolean waitForCompletion) {
+        this.waitForCompletion = waitForCompletion;
+        return this;
+    }
+
+    /**
+     * Returns wait for completion setting
+     *
+     * @return true if the operation will wait for completion
+     */
+    public boolean waitForCompletion() {
+        return waitForCompletion;
+    }
+
+    /**
+     * Set the value for restoreAllShards, denoting whether to restore all shards or only unassigned shards
+     *
+     * @param restoreAllShards If true, the operation will restore all the shards of the given indices.
+     *                         If false, the operation will restore only the unassigned shards of the given indices.
+     * @return this request
+     */
+    public RestoreRemoteStoreRequest restoreAllShards(boolean restoreAllShards) {
+        this.restoreAllShards = restoreAllShards;
+        return this;
+    }
+
+    /**
+     * Returns restoreAllShards setting
+     *
+     * @return true if the operation will restore all the shards of the given indices
+     */
+    public boolean restoreAllShards() {
+        return restoreAllShards;
+    }
+
+    /**
+     * Parses restore definition
+     *
+     * @param source restore definition
+     * @return this request
+     */
+    @SuppressWarnings("unchecked")
+    public RestoreRemoteStoreRequest source(Map<String, Object> source) {
+        for (Map.Entry<String, Object> entry : source.entrySet()) {
+            String name = entry.getKey();
+            if (name.equals("indices")) {
+                if (entry.getValue() instanceof String) {
+                    indices(Strings.splitStringByCommaToArray((String) entry.getValue()));
+                } else if (entry.getValue() instanceof ArrayList) {
+                    indices((ArrayList<String>) entry.getValue());
+                } else {
+                    throw new IllegalArgumentException("malformed indices section, should be an array of strings");
+                }
+            } else {
+                if (IndicesOptions.isIndicesOptions(name) == false) {
+                    throw new IllegalArgumentException("Unknown parameter " + name);
+                }
+            }
+        }
+        return this;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.startArray("indices");
+        for (String index : indices) {
+            builder.value(index);
+        }
+        builder.endArray();
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public String getDescription() {
+        return "remote_store";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        RestoreRemoteStoreRequest that = (RestoreRemoteStoreRequest) o;
+        return waitForCompletion == that.waitForCompletion
+            && restoreAllShards == that.restoreAllShards
+            && Arrays.equals(indices, that.indices);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Objects.hash(waitForCompletion, restoreAllShards);
+        result = 31 * result + Arrays.hashCode(indices);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponse.java
new file mode 100644
index 0000000000000..66908889b0641
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponse.java
@@ -0,0 +1,126 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.snapshots.RestoreInfo;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+
+/**
+ * Contains information about remote store restores
+ *
+ * @opensearch.internal
+ */
+public final class RestoreRemoteStoreResponse extends ActionResponse implements ToXContentObject {
+
+    @Nullable
+    private final RestoreInfo restoreInfo;
+
+    public RestoreRemoteStoreResponse(@Nullable RestoreInfo restoreInfo) {
+        this.restoreInfo = restoreInfo;
+    }
+
+    public RestoreRemoteStoreResponse(StreamInput in) throws IOException {
+        super(in);
+        restoreInfo = RestoreInfo.readOptionalRestoreInfo(in);
+    }
+
+    /**
+     * Returns restore information if remote store restore was completed before this method returned, null otherwise
+     *
+     * @return restore information or null
+     */
+    public RestoreInfo getRestoreInfo() {
+        return restoreInfo;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeOptionalWriteable(restoreInfo);
+    }
+
+    public RestStatus status() {
+        if (restoreInfo == null) {
+            return RestStatus.ACCEPTED;
+        }
+        return restoreInfo.status();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (restoreInfo != null) {
+            builder.field("remote_store");
+            restoreInfo.toXContent(builder, params);
+        } else {
+            builder.field("accepted", true);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    public static final ConstructingObjectParser<RestoreRemoteStoreResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "restore_remote_store",
+        true,
+        v -> {
+            RestoreInfo restoreInfo = (RestoreInfo) v[0];
+            Boolean accepted = (Boolean) v[1];
+            assert (accepted == null && restoreInfo != null) || (accepted != null && accepted && restoreInfo == null) : "accepted: ["
+                + accepted
+                + "], restoreInfo: ["
+                + restoreInfo
+                + "]";
+            return new RestoreRemoteStoreResponse(restoreInfo);
+        }
+    );
+
+    static {
+        PARSER.declareObject(
+            optionalConstructorArg(),
+            (parser, context) -> RestoreInfo.fromXContent(parser),
+            new ParseField("remote_store")
+        );
+        PARSER.declareBoolean(optionalConstructorArg(), new ParseField("accepted"));
+    }
+
+    public static RestoreRemoteStoreResponse fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        RestoreRemoteStoreResponse that = (RestoreRemoteStoreResponse) o;
+        return Objects.equals(restoreInfo, that.restoreInfo);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(restoreInfo);
+    }
+
+    @Override
+    public String toString() {
+        return "RestoreRemoteStoreResponse{" + "restoreInfo=" + restoreInfo + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/TransportRestoreRemoteStoreAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/TransportRestoreRemoteStoreAction.java
new file mode 100644
index 0000000000000..2b0e5c74cad53
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/TransportRestoreRemoteStoreAction.java
@@ -0,0 +1,100 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.action.admin.cluster.snapshots.restore.RestoreClusterStateListener;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.recovery.RemoteStoreRestoreService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for restore remote store operation
+ *
+ * @opensearch.internal
+ */
+public final class TransportRestoreRemoteStoreAction extends TransportClusterManagerNodeAction<
+    RestoreRemoteStoreRequest,
+    RestoreRemoteStoreResponse> {
+    private final RemoteStoreRestoreService restoreService;
+
+    @Inject
+    public TransportRestoreRemoteStoreAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        RemoteStoreRestoreService restoreService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            RestoreRemoteStoreAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            RestoreRemoteStoreRequest::new,
+            indexNameExpressionResolver
+        );
+        this.restoreService = restoreService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.GENERIC;
+    }
+
+    @Override
+    protected RestoreRemoteStoreResponse read(StreamInput in) throws IOException {
+        return new RestoreRemoteStoreResponse(in);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(RestoreRemoteStoreRequest request, ClusterState state) {
+        // Restoring a remote store might change the global state and create/change an index,
+        // so we need to check for METADATA_WRITE and WRITE blocks
+        ClusterBlockException blockException = state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+        if (blockException != null) {
+            return blockException;
+        }
+        return state.blocks().globalBlockedException(ClusterBlockLevel.WRITE);
+
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        final RestoreRemoteStoreRequest request,
+        final ClusterState state,
+        final ActionListener<RestoreRemoteStoreResponse> listener
+    ) {
+        restoreService.restore(request, ActionListener.delegateFailure(listener, (delegatedListener, restoreCompletionResponse) -> {
+            if (restoreCompletionResponse.getRestoreInfo() == null && request.waitForCompletion()) {
+                RestoreClusterStateListener.createAndRegisterListener(
+                    clusterService,
+                    restoreCompletionResponse,
+                    delegatedListener,
+                    RestoreRemoteStoreResponse::new
+                );
+            } else {
+                delegatedListener.onResponse(new RestoreRemoteStoreResponse(restoreCompletionResponse.getRestoreInfo()));
+            }
+        }));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/package-info.java
new file mode 100644
index 0000000000000..10348f5ccfe6e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/restore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Restore remote store transport handler. */
+package org.opensearch.action.admin.cluster.remotestore.restore;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStats.java
new file mode 100644
index 0000000000000..f292fcec7ccac
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStats.java
@@ -0,0 +1,393 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+
+import java.io.IOException;
+
+/**
+ * Encapsulates all remote store stats
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStats implements Writeable, ToXContentFragment {
+    /**
+     * Stats related to Remote Segment Store operations
+     */
+    private final RemoteSegmentTransferTracker.Stats remoteSegmentShardStats;
+
+    /**
+     * Stats related to Remote Translog Store operations
+     */
+    private final RemoteTranslogTransferTracker.Stats remoteTranslogShardStats;
+    private final ShardRouting shardRouting;
+
+    RemoteStoreStats(
+        RemoteSegmentTransferTracker.Stats remoteSegmentUploadShardStats,
+        RemoteTranslogTransferTracker.Stats remoteTranslogShardStats,
+        ShardRouting shardRouting
+    ) {
+        this.remoteSegmentShardStats = remoteSegmentUploadShardStats;
+        this.remoteTranslogShardStats = remoteTranslogShardStats;
+        this.shardRouting = shardRouting;
+    }
+
+    RemoteStoreStats(StreamInput in) throws IOException {
+        remoteSegmentShardStats = in.readOptionalWriteable(RemoteSegmentTransferTracker.Stats::new);
+        remoteTranslogShardStats = in.readOptionalWriteable(RemoteTranslogTransferTracker.Stats::new);
+        this.shardRouting = new ShardRouting(in);
+    }
+
+    public RemoteSegmentTransferTracker.Stats getSegmentStats() {
+        return remoteSegmentShardStats;
+    }
+
+    public ShardRouting getShardRouting() {
+        return shardRouting;
+    }
+
+    public RemoteTranslogTransferTracker.Stats getTranslogStats() {
+        return remoteTranslogShardStats;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        buildShardRouting(builder);
+
+        builder.startObject(Fields.SEGMENT);
+        builder.startObject(SubFields.DOWNLOAD);
+        // Ensuring that we are not showing 0 metrics to the user
+        if (remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesStarted != 0) {
+            buildSegmentDownloadStats(builder);
+        }
+        builder.endObject(); // segment.download
+        builder.startObject(SubFields.UPLOAD);
+        // Ensuring that we are not showing 0 metrics to the user
+        if (remoteSegmentShardStats.totalUploadsStarted != 0) {
+            buildSegmentUploadStats(builder);
+        }
+        builder.endObject(); // segment.upload
+        builder.endObject(); // segment
+
+        builder.startObject(Fields.TRANSLOG);
+        builder.startObject(SubFields.UPLOAD);
+        // Ensuring that we are not showing 0 metrics to the user
+        if (remoteTranslogShardStats.totalUploadsStarted > 0) {
+            buildTranslogUploadStats(builder);
+        }
+        builder.endObject(); // translog.upload
+        builder.startObject(SubFields.DOWNLOAD);
+        // Ensuring that we are not showing 0 metrics to the user
+        if (remoteTranslogShardStats.totalDownloadsSucceeded > 0) {
+            buildTranslogDownloadStats(builder);
+        }
+        builder.endObject(); // translog.download
+        builder.endObject(); // translog
+
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeOptionalWriteable(remoteSegmentShardStats);
+        out.writeOptionalWriteable(remoteTranslogShardStats);
+        shardRouting.writeTo(out);
+    }
+
+    private void buildTranslogUploadStats(XContentBuilder builder) throws IOException {
+        builder.field(UploadStatsFields.LAST_SUCCESSFUL_UPLOAD_TIMESTAMP, remoteTranslogShardStats.lastSuccessfulUploadTimestamp);
+
+        builder.startObject(UploadStatsFields.TOTAL_UPLOADS);
+        builder.field(SubFields.STARTED, remoteTranslogShardStats.totalUploadsStarted)
+            .field(SubFields.FAILED, remoteTranslogShardStats.totalUploadsFailed)
+            .field(SubFields.SUCCEEDED, remoteTranslogShardStats.totalUploadsSucceeded);
+        builder.endObject();
+
+        builder.startObject(UploadStatsFields.TOTAL_UPLOAD_SIZE);
+        builder.field(SubFields.STARTED_BYTES, remoteTranslogShardStats.uploadBytesStarted)
+            .field(SubFields.FAILED_BYTES, remoteTranslogShardStats.uploadBytesFailed)
+            .field(SubFields.SUCCEEDED_BYTES, remoteTranslogShardStats.uploadBytesSucceeded);
+        builder.endObject();
+
+        builder.field(UploadStatsFields.TOTAL_UPLOAD_TIME_IN_MILLIS, remoteTranslogShardStats.totalUploadTimeInMillis);
+
+        builder.startObject(UploadStatsFields.UPLOAD_SIZE_IN_BYTES);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.uploadBytesMovingAverage);
+        builder.endObject();
+
+        builder.startObject(UploadStatsFields.UPLOAD_SPEED_IN_BYTES_PER_SEC);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.uploadBytesPerSecMovingAverage);
+        builder.endObject();
+
+        builder.startObject(UploadStatsFields.UPLOAD_TIME_IN_MILLIS);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.uploadTimeMovingAverage);
+        builder.endObject();
+    }
+
+    private void buildTranslogDownloadStats(XContentBuilder builder) throws IOException {
+        builder.field(DownloadStatsFields.LAST_SUCCESSFUL_DOWNLOAD_TIMESTAMP, remoteTranslogShardStats.lastSuccessfulDownloadTimestamp);
+
+        builder.startObject(DownloadStatsFields.TOTAL_DOWNLOADS);
+        builder.field(SubFields.SUCCEEDED, remoteTranslogShardStats.totalDownloadsSucceeded);
+        builder.endObject();
+
+        builder.startObject(DownloadStatsFields.TOTAL_DOWNLOAD_SIZE);
+        builder.field(SubFields.SUCCEEDED_BYTES, remoteTranslogShardStats.downloadBytesSucceeded);
+        builder.endObject();
+
+        builder.field(DownloadStatsFields.TOTAL_DOWNLOAD_TIME_IN_MILLIS, remoteTranslogShardStats.totalDownloadTimeInMillis);
+
+        builder.startObject(DownloadStatsFields.DOWNLOAD_SIZE_IN_BYTES);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.downloadBytesMovingAverage);
+        builder.endObject();
+
+        builder.startObject(DownloadStatsFields.DOWNLOAD_SPEED_IN_BYTES_PER_SEC);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.downloadBytesPerSecMovingAverage);
+        builder.endObject();
+
+        builder.startObject(DownloadStatsFields.DOWNLOAD_TIME_IN_MILLIS);
+        builder.field(SubFields.MOVING_AVG, remoteTranslogShardStats.downloadTimeMovingAverage);
+        builder.endObject();
+    }
+
+    private void buildSegmentUploadStats(XContentBuilder builder) throws IOException {
+        builder.field(UploadStatsFields.LOCAL_REFRESH_TIMESTAMP, remoteSegmentShardStats.localRefreshClockTimeMs)
+            .field(UploadStatsFields.REMOTE_REFRESH_TIMESTAMP, remoteSegmentShardStats.remoteRefreshClockTimeMs)
+            .field(UploadStatsFields.REFRESH_TIME_LAG_IN_MILLIS, remoteSegmentShardStats.refreshTimeLagMs)
+            .field(UploadStatsFields.REFRESH_LAG, remoteSegmentShardStats.localRefreshNumber - remoteSegmentShardStats.remoteRefreshNumber)
+            .field(UploadStatsFields.BYTES_LAG, remoteSegmentShardStats.bytesLag)
+            .field(UploadStatsFields.BACKPRESSURE_REJECTION_COUNT, remoteSegmentShardStats.rejectionCount)
+            .field(UploadStatsFields.CONSECUTIVE_FAILURE_COUNT, remoteSegmentShardStats.consecutiveFailuresCount);
+        builder.startObject(UploadStatsFields.TOTAL_UPLOADS)
+            .field(SubFields.STARTED, remoteSegmentShardStats.totalUploadsStarted)
+            .field(SubFields.SUCCEEDED, remoteSegmentShardStats.totalUploadsSucceeded)
+            .field(SubFields.FAILED, remoteSegmentShardStats.totalUploadsFailed);
+        builder.endObject();
+        builder.startObject(UploadStatsFields.TOTAL_UPLOAD_SIZE)
+            .field(SubFields.STARTED_BYTES, remoteSegmentShardStats.uploadBytesStarted)
+            .field(SubFields.SUCCEEDED_BYTES, remoteSegmentShardStats.uploadBytesSucceeded)
+            .field(SubFields.FAILED_BYTES, remoteSegmentShardStats.uploadBytesFailed);
+        builder.endObject();
+        builder.startObject(UploadStatsFields.REMOTE_REFRESH_SIZE_IN_BYTES)
+            .field(SubFields.LAST_SUCCESSFUL, remoteSegmentShardStats.lastSuccessfulRemoteRefreshBytes)
+            .field(SubFields.MOVING_AVG, remoteSegmentShardStats.uploadBytesMovingAverage);
+        builder.endObject();
+        builder.startObject(UploadStatsFields.UPLOAD_SPEED_IN_BYTES_PER_SEC)
+            .field(SubFields.MOVING_AVG, remoteSegmentShardStats.uploadBytesPerSecMovingAverage);
+        builder.endObject();
+        builder.startObject(UploadStatsFields.REMOTE_REFRESH_LATENCY_IN_MILLIS)
+            .field(SubFields.MOVING_AVG, remoteSegmentShardStats.uploadTimeMovingAverage);
+        builder.endObject();
+    }
+
+    private void buildSegmentDownloadStats(XContentBuilder builder) throws IOException {
+        builder.field(
+            DownloadStatsFields.LAST_SYNC_TIMESTAMP,
+            remoteSegmentShardStats.directoryFileTransferTrackerStats.lastTransferTimestampMs
+        );
+        builder.startObject(DownloadStatsFields.TOTAL_DOWNLOAD_SIZE)
+            .field(SubFields.STARTED_BYTES, remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesStarted)
+            .field(SubFields.SUCCEEDED_BYTES, remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesSucceeded)
+            .field(SubFields.FAILED_BYTES, remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesFailed);
+        builder.endObject();
+        builder.startObject(DownloadStatsFields.DOWNLOAD_SIZE_IN_BYTES)
+            .field(SubFields.LAST_SUCCESSFUL, remoteSegmentShardStats.directoryFileTransferTrackerStats.lastSuccessfulTransferInBytes)
+            .field(SubFields.MOVING_AVG, remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesMovingAverage);
+        builder.endObject();
+        builder.startObject(DownloadStatsFields.DOWNLOAD_SPEED_IN_BYTES_PER_SEC)
+            .field(SubFields.MOVING_AVG, remoteSegmentShardStats.directoryFileTransferTrackerStats.transferredBytesPerSecMovingAverage);
+        builder.endObject();
+    }
+
+    private void buildShardRouting(XContentBuilder builder) throws IOException {
+        builder.startObject(Fields.ROUTING);
+        builder.field(RoutingFields.STATE, shardRouting.state());
+        builder.field(RoutingFields.PRIMARY, shardRouting.primary());
+        builder.field(RoutingFields.NODE_ID, shardRouting.currentNodeId());
+        builder.endObject();
+    }
+
+    /**
+     * Fields for remote store stats response
+     */
+    static final class Fields {
+        static final String ROUTING = "routing";
+        static final String SEGMENT = "segment";
+        static final String TRANSLOG = "translog";
+    }
+
+    static final class RoutingFields {
+        static final String STATE = "state";
+        static final String PRIMARY = "primary";
+        static final String NODE_ID = "node";
+    }
+
+    /**
+     * Fields for remote store stats response
+     */
+    public static final class UploadStatsFields {
+        /**
+         * Lag in terms of bytes b/w local and remote store
+         */
+        static final String BYTES_LAG = "bytes_lag";
+
+        /**
+         * No of refresh remote store is lagging behind local
+         */
+        static final String REFRESH_LAG = "refresh_lag";
+
+        /**
+         * Time in millis remote refresh is behind local refresh
+         */
+        static final String REFRESH_TIME_LAG_IN_MILLIS = "refresh_time_lag_in_millis";
+
+        /**
+         * Last successful local refresh timestamp in milliseconds
+         */
+        static final String LOCAL_REFRESH_TIMESTAMP = "local_refresh_timestamp_in_millis";
+
+        /**
+         * Last successful remote refresh timestamp in milliseconds
+         */
+        static final String REMOTE_REFRESH_TIMESTAMP = "remote_refresh_timestamp_in_millis";
+
+        /**
+         * Total write rejections due to remote store backpressure kick in
+         */
+        static final String BACKPRESSURE_REJECTION_COUNT = "backpressure_rejection_count";
+
+        /**
+         * No of consecutive remote refresh failures without a single success since the first failures
+         */
+        static final String CONSECUTIVE_FAILURE_COUNT = "consecutive_failure_count";
+
+        /**
+         * Represents the size of new data to be uploaded as part of a refresh
+         */
+        static final String REMOTE_REFRESH_SIZE_IN_BYTES = "remote_refresh_size_in_bytes";
+
+        /**
+         * Time taken by a single remote refresh
+         */
+        static final String REMOTE_REFRESH_LATENCY_IN_MILLIS = "remote_refresh_latency_in_millis";
+
+        /**
+         * Timestamp of last successful remote store upload
+         */
+        static final String LAST_SUCCESSFUL_UPLOAD_TIMESTAMP = "last_successful_upload_timestamp";
+
+        /**
+         * Count of files uploaded to remote store
+         */
+        public static final String TOTAL_UPLOADS = "total_uploads";
+
+        /**
+         * Represents the total uploads to remote store in bytes
+         */
+        public static final String TOTAL_UPLOAD_SIZE = "total_upload_size";
+
+        /**
+         * Total time spent on remote store uploads
+         */
+        static final String TOTAL_UPLOAD_TIME_IN_MILLIS = "total_upload_time_in_millis";
+
+        /**
+         * Represents the size of new data to be transferred as part of a remote store upload
+         */
+        static final String UPLOAD_SIZE_IN_BYTES = "upload_size_in_bytes";
+
+        /**
+         * Represents the speed of remote store uploads in bytes per sec
+         */
+        static final String UPLOAD_SPEED_IN_BYTES_PER_SEC = "upload_speed_in_bytes_per_sec";
+
+        /**
+         * Time taken by a remote store upload
+         */
+        static final String UPLOAD_TIME_IN_MILLIS = "upload_time_in_millis";
+    }
+
+    static final class DownloadStatsFields {
+        /**
+         * Epoch timestamp of the last successful download
+         */
+        public static final String LAST_SUCCESSFUL_DOWNLOAD_TIMESTAMP = "last_successful_download_timestamp";
+
+        /**
+         * Last successful sync from remote in milliseconds
+         */
+        static final String LAST_SYNC_TIMESTAMP = "last_sync_timestamp";
+
+        /**
+         * Count of files downloaded from remote store
+         */
+        public static final String TOTAL_DOWNLOADS = "total_downloads";
+
+        /**
+         * Total time spent in downloads from remote store
+         */
+        public static final String TOTAL_DOWNLOAD_TIME_IN_MILLIS = "total_download_time_in_millis";
+
+        /**
+         * Total bytes of files downloaded from the remote store
+         */
+        static final String TOTAL_DOWNLOAD_SIZE = "total_download_size";
+
+        /**
+         * Average size of a file downloaded from the remote store
+         */
+        static final String DOWNLOAD_SIZE_IN_BYTES = "download_size_in_bytes";
+
+        /**
+         * Average speed (in bytes/sec) of a remote store download
+         */
+        static final String DOWNLOAD_SPEED_IN_BYTES_PER_SEC = "download_speed_in_bytes_per_sec";
+
+        /**
+         * Average time spent on a remote store download
+         */
+        public static final String DOWNLOAD_TIME_IN_MILLIS = "download_time_in_millis";
+    }
+
+    /**
+     * Reusable sub fields for {@link UploadStatsFields} and {@link DownloadStatsFields}
+     */
+    public static final class SubFields {
+        public static final String STARTED = "started";
+        public static final String SUCCEEDED = "succeeded";
+        public static final String FAILED = "failed";
+
+        public static final String STARTED_BYTES = "started_bytes";
+        public static final String SUCCEEDED_BYTES = "succeeded_bytes";
+        public static final String FAILED_BYTES = "failed_bytes";
+
+        static final String DOWNLOAD = "download";
+        public static final String UPLOAD = "upload";
+
+        /**
+         * Moving avg over last N values stat
+         */
+        static final String MOVING_AVG = "moving_avg";
+
+        /**
+         * Most recent successful attempt stat
+         */
+        static final String LAST_SUCCESSFUL = "last_successful";
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsAction.java
new file mode 100644
index 0000000000000..98c6e863b7b61
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Remote store stats action
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStatsAction extends ActionType<RemoteStoreStatsResponse> {
+
+    public static final RemoteStoreStatsAction INSTANCE = new RemoteStoreStatsAction();
+    public static final String NAME = "cluster:monitor/_remotestore/stats";
+
+    private RemoteStoreStatsAction() {
+        super(NAME, RemoteStoreStatsResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequest.java
new file mode 100644
index 0000000000000..f09cf79c5154c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequest.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.action.support.broadcast.BroadcastRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Encapsulates all remote store stats
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStatsRequest extends BroadcastRequest<RemoteStoreStatsRequest> {
+
+    private String[] shards;
+    private boolean local = false;
+
+    public RemoteStoreStatsRequest() {
+        super((String[]) null);
+        shards = new String[0];
+    }
+
+    public RemoteStoreStatsRequest(StreamInput in) throws IOException {
+        super(in);
+        shards = in.readStringArray();
+        local = in.readBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(shards);
+        out.writeBoolean(local);
+    }
+
+    public RemoteStoreStatsRequest shards(String... shards) {
+        this.shards = shards;
+        return this;
+    }
+
+    public String[] shards() {
+        return this.shards;
+    }
+
+    public void local(boolean local) {
+        this.local = local;
+    }
+
+    public boolean local() {
+        return local;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestBuilder.java
new file mode 100644
index 0000000000000..c31e4a1fd6178
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestBuilder.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.common.unit.TimeValue;
+
+/**
+ * Builder for RemoteStoreStatsRequest
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStatsRequestBuilder extends BroadcastOperationRequestBuilder<
+    RemoteStoreStatsRequest,
+    RemoteStoreStatsResponse,
+    RemoteStoreStatsRequestBuilder> {
+
+    public RemoteStoreStatsRequestBuilder(OpenSearchClient client, RemoteStoreStatsAction action) {
+        super(client, action, new RemoteStoreStatsRequest());
+    }
+
+    /**
+     * Sets timeout of request.
+     */
+    public final RemoteStoreStatsRequestBuilder setTimeout(TimeValue timeout) {
+        request.timeout(timeout);
+        return this;
+    }
+
+    /**
+     * Sets shards preference of request.
+     */
+    public final RemoteStoreStatsRequestBuilder setShards(String... shards) {
+        request.shards(shards);
+        return this;
+    }
+
+    /**
+     * Sets local shards preference of request.
+     */
+    public final RemoteStoreStatsRequestBuilder setLocal(boolean local) {
+        request.local(local);
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponse.java
new file mode 100644
index 0000000000000..63a4c97d695b7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponse.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.action.support.broadcast.BroadcastResponse;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Remote Store stats response
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStatsResponse extends BroadcastResponse {
+
+    private final RemoteStoreStats[] remoteStoreStats;
+
+    public RemoteStoreStatsResponse(StreamInput in) throws IOException {
+        super(in);
+        remoteStoreStats = in.readArray(RemoteStoreStats::new, RemoteStoreStats[]::new);
+    }
+
+    public RemoteStoreStatsResponse(
+        RemoteStoreStats[] remoteStoreStats,
+        int totalShards,
+        int successfulShards,
+        int failedShards,
+        List<DefaultShardOperationFailedException> shardFailures
+    ) {
+        super(totalShards, successfulShards, failedShards, shardFailures);
+        this.remoteStoreStats = remoteStoreStats;
+    }
+
+    public RemoteStoreStats[] getRemoteStoreStats() {
+        return this.remoteStoreStats;
+    }
+
+    public Map<String, Map<Integer, List<RemoteStoreStats>>> groupByIndexAndShards() {
+        Map<String, Map<Integer, List<RemoteStoreStats>>> indexWiseStats = new HashMap<>();
+        for (RemoteStoreStats shardStat : remoteStoreStats) {
+            indexWiseStats.computeIfAbsent(shardStat.getShardRouting().getIndexName(), k -> new HashMap<>())
+                .computeIfAbsent(shardStat.getShardRouting().getId(), k -> new ArrayList<>())
+                .add(shardStat);
+        }
+        return indexWiseStats;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeArray(remoteStoreStats);
+    }
+
+    @Override
+    protected void addCustomXContentFields(XContentBuilder builder, Params params) throws IOException {
+        Map<String, Map<Integer, List<RemoteStoreStats>>> indexWiseStats = groupByIndexAndShards();
+        builder.startObject(Fields.INDICES);
+        for (String indexName : indexWiseStats.keySet()) {
+            builder.startObject(indexName);
+            builder.startObject(Fields.SHARDS);
+            for (int shardId : indexWiseStats.get(indexName).keySet()) {
+                builder.startArray(Integer.toString(shardId));
+                for (RemoteStoreStats shardStat : indexWiseStats.get(indexName).get(shardId)) {
+                    shardStat.toXContent(builder, params);
+                }
+                builder.endArray();
+            }
+            builder.endObject();
+            builder.endObject();
+        }
+        builder.endObject();
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, false);
+    }
+
+    static final class Fields {
+        static final String SHARDS = "shards";
+        static final String INDICES = "indices";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsAction.java
new file mode 100644
index 0000000000000..bd8db4a160bf6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsAction.java
@@ -0,0 +1,168 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.PlainShardsIterator;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardsIterator;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.ShardNotFoundException;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+/**
+ * Encapsulates all remote store stats
+ *
+ * @opensearch.internal
+ */
+public class TransportRemoteStoreStatsAction extends TransportBroadcastByNodeAction<
+    RemoteStoreStatsRequest,
+    RemoteStoreStatsResponse,
+    RemoteStoreStats> {
+
+    private final IndicesService indicesService;
+
+    private final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    @Inject
+    public TransportRemoteStoreStatsAction(
+        ClusterService clusterService,
+        TransportService transportService,
+        IndicesService indicesService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
+    ) {
+        super(
+            RemoteStoreStatsAction.NAME,
+            clusterService,
+            transportService,
+            actionFilters,
+            indexNameExpressionResolver,
+            RemoteStoreStatsRequest::new,
+            ThreadPool.Names.MANAGEMENT
+        );
+        this.indicesService = indicesService;
+        this.remoteStoreStatsTrackerFactory = remoteStoreStatsTrackerFactory;
+    }
+
+    /**
+     * Status goes across *all* shards.
+     */
+    @Override
+    protected ShardsIterator shards(ClusterState clusterState, RemoteStoreStatsRequest request, String[] concreteIndices) {
+        final List<ShardRouting> newShardRoutings = new ArrayList<>();
+        if (request.shards().length > 0) {
+            clusterState.routingTable().allShards(concreteIndices).getShardRoutings().forEach(shardRouting -> {
+                if (Arrays.asList(request.shards()).contains(Integer.toString(shardRouting.shardId().id()))) {
+                    newShardRoutings.add(shardRouting);
+                }
+            });
+        } else {
+            newShardRoutings.addAll(clusterState.routingTable().allShards(concreteIndices).getShardRoutings());
+        }
+        return new PlainShardsIterator(
+            newShardRoutings.stream()
+                .filter(
+                    shardRouting -> !request.local()
+                        || (shardRouting.currentNodeId() == null
+                            || shardRouting.currentNodeId().equals(clusterState.getNodes().getLocalNodeId()))
+                )
+                .filter(
+                    shardRouting -> Boolean.parseBoolean(
+                        clusterState.getMetadata().index(shardRouting.index()).getSettings().get(IndexMetadata.SETTING_REMOTE_STORE_ENABLED)
+                    )
+                )
+                .collect(Collectors.toList())
+        );
+    }
+
+    @Override
+    protected ClusterBlockException checkGlobalBlock(ClusterState state, RemoteStoreStatsRequest request) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+
+    @Override
+    protected ClusterBlockException checkRequestBlock(ClusterState state, RemoteStoreStatsRequest request, String[] concreteIndices) {
+        return state.blocks().indicesBlockedException(ClusterBlockLevel.METADATA_READ, concreteIndices);
+    }
+
+    @Override
+    protected RemoteStoreStats readShardResult(StreamInput in) throws IOException {
+        return new RemoteStoreStats(in);
+    }
+
+    @Override
+    protected RemoteStoreStatsResponse newResponse(
+        RemoteStoreStatsRequest request,
+        int totalShards,
+        int successfulShards,
+        int failedShards,
+        List<RemoteStoreStats> responses,
+        List<DefaultShardOperationFailedException> shardFailures,
+        ClusterState clusterState
+    ) {
+        return new RemoteStoreStatsResponse(
+            responses.toArray(new RemoteStoreStats[0]),
+            totalShards,
+            successfulShards,
+            failedShards,
+            shardFailures
+        );
+    }
+
+    @Override
+    protected RemoteStoreStatsRequest readRequestFrom(StreamInput in) throws IOException {
+        return new RemoteStoreStatsRequest(in);
+    }
+
+    @Override
+    protected RemoteStoreStats shardOperation(RemoteStoreStatsRequest request, ShardRouting shardRouting) {
+        IndexService indexService = indicesService.indexServiceSafe(shardRouting.shardId().getIndex());
+        IndexShard indexShard = indexService.getShard(shardRouting.shardId().id());
+        // if we don't have the routing entry yet, we need it stats wise, we treat it as if the shard is not ready yet
+        if (indexShard.routingEntry() == null) {
+            throw new ShardNotFoundException(indexShard.shardId());
+        }
+
+        RemoteSegmentTransferTracker remoteSegmentTransferTracker = remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(
+            indexShard.shardId()
+        );
+        assert Objects.nonNull(remoteSegmentTransferTracker);
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = remoteStoreStatsTrackerFactory.getRemoteTranslogTransferTracker(
+            indexShard.shardId()
+        );
+        assert Objects.nonNull(remoteTranslogTransferTracker);
+
+        return new RemoteStoreStats(remoteSegmentTransferTracker.stats(), remoteTranslogTransferTracker.stats(), indexShard.routingEntry());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/package-info.java
new file mode 100644
index 0000000000000..80bd96e3245d9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/remotestore/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Remote store stats transport handler. */
+package org.opensearch.action.admin.cluster.remotestore.stats;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryAction.java
index 4feb755c3e5a1..0ec1281648cdb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryAction.java
@@ -33,6 +33,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for cleaning up snapshot repositories
+ *
+ * @opensearch.internal
+ */
 public final class CleanupRepositoryAction extends ActionType<CleanupRepositoryResponse> {
 
     public static final CleanupRepositoryAction INSTANCE = new CleanupRepositoryAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequest.java
index d1fc914201390..7e3f4cd95fc72 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequest.java
@@ -33,13 +33,18 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport request for cleaning up snapshot repositories
+ *
+ * @opensearch.internal
+ */
 public class CleanupRepositoryRequest extends AcknowledgedRequest<CleanupRepositoryRequest> {
 
     private String repository;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequestBuilder.java
index b5db8d7eca669..95c4fb372572f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryRequestBuilder.java
@@ -32,10 +32,15 @@
 package org.opensearch.action.admin.cluster.repositories.cleanup;
 
 import org.opensearch.action.ActionType;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class CleanupRepositoryRequestBuilder extends MasterNodeOperationRequestBuilder<
+/**
+ * Transport builder for cleaning up snapshot repositories
+ *
+ * @opensearch.internal
+ */
+public class CleanupRepositoryRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     CleanupRepositoryRequest,
     CleanupRepositoryResponse,
     CleanupRepositoryRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryResponse.java
index e6bb65e732082..99af862c769e8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/CleanupRepositoryResponse.java
@@ -31,18 +31,23 @@
 
 package org.opensearch.action.admin.cluster.repositories.cleanup;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.repositories.RepositoryCleanupResult;
 
 import java.io.IOException;
 
+/**
+ * Transport response for cleaning up snapshot repositories
+ *
+ * @opensearch.internal
+ */
 public final class CleanupRepositoryResponse extends ActionResponse implements ToXContentObject {
 
     private static final ObjectParser<CleanupRepositoryResponse, Void> PARSER = new ObjectParser<>(
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/TransportCleanupRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/TransportCleanupRepositoryAction.java
index b7b9da675a385..fa22daf2ca038 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/TransportCleanupRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/TransportCleanupRepositoryAction.java
@@ -36,11 +36,10 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.RepositoryCleanupInProgress;
@@ -53,7 +52,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
 import org.opensearch.repositories.RepositoryCleanupResult;
@@ -73,17 +74,21 @@
  * <ol>
  *     <li>Check that there are no running repository cleanup, snapshot create, or snapshot delete actions
  *     and add an entry for the repository that is to be cleaned up to {@link RepositoryCleanupInProgress}</li>
- *     <li>Run cleanup actions on the repository. Note, these are executed exclusively on the master node.
+ *     <li>Run cleanup actions on the repository. Note, these are executed exclusively on the cluster-manager node.
  *     For the precise operations execute see {@link BlobStoreRepository#cleanup}</li>
  *     <li>Remove the entry in {@link RepositoryCleanupInProgress} in the first step.</li>
  * </ol>
  *
- * On master failover during the cleanup operation it is simply removed from the cluster state. This is safe because the logic in
+ * On cluster-manager failover during the cleanup operation it is simply removed from the cluster state. This is safe because the logic in
  * {@link BlobStoreRepository#cleanup} ensures that the repository state id has not changed between creation of the cluster state entry
  * and any delete/write operations. TODO: This will not work if we also want to clean up at the shard level as those will involve writes
  *                                        as well as deletes.
+ *
+ * @opensearch.internal
  */
-public final class TransportCleanupRepositoryAction extends TransportMasterNodeAction<CleanupRepositoryRequest, CleanupRepositoryResponse> {
+public final class TransportCleanupRepositoryAction extends TransportClusterManagerNodeAction<
+    CleanupRepositoryRequest,
+    CleanupRepositoryResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportCleanupRepositoryAction.class);
 
@@ -93,6 +98,8 @@ public final class TransportCleanupRepositoryAction extends TransportMasterNodeA
 
     private final SnapshotsService snapshotsService;
 
+    private final RemoteStoreLockManagerFactory remoteStoreLockManagerFactory;
+
     @Override
     protected String executor() {
         return ThreadPool.Names.SAME;
@@ -119,24 +126,25 @@ public TransportCleanupRepositoryAction(
         );
         this.repositoriesService = repositoriesService;
         this.snapshotsService = snapshotsService;
-        // We add a state applier that will remove any dangling repository cleanup actions on master failover.
+        this.remoteStoreLockManagerFactory = new RemoteStoreLockManagerFactory(() -> repositoriesService);
+        // We add a state applier that will remove any dangling repository cleanup actions on cluster-manager failover.
         // This is safe to do since cleanups will increment the repository state id before executing any operations to prevent concurrent
         // operations from corrupting the repository. This is the same safety mechanism used by snapshot deletes.
-        if (DiscoveryNode.isMasterNode(clusterService.getSettings())) {
+        if (DiscoveryNode.isClusterManagerNode(clusterService.getSettings())) {
             addClusterStateApplier(clusterService);
         }
     }
 
     private static void addClusterStateApplier(ClusterService clusterService) {
         clusterService.addStateApplier(event -> {
-            if (event.localNodeMaster() && event.previousState().nodes().isLocalNodeElectedMaster() == false) {
+            if (event.localNodeClusterManager() && event.previousState().nodes().isLocalNodeElectedClusterManager() == false) {
                 final RepositoryCleanupInProgress repositoryCleanupInProgress = event.state()
                     .custom(RepositoryCleanupInProgress.TYPE, RepositoryCleanupInProgress.EMPTY);
                 if (repositoryCleanupInProgress.hasCleanupInProgress() == false) {
                     return;
                 }
                 clusterService.submitStateUpdateTask(
-                    "clean up repository cleanup task after master failover",
+                    "clean up repository cleanup task after cluster-manager failover",
                     new ClusterStateUpdateTask() {
                         @Override
                         public ClusterState execute(ClusterState currentState) {
@@ -170,7 +178,7 @@ protected CleanupRepositoryResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         CleanupRepositoryRequest request,
         ClusterState state,
         ActionListener<CleanupRepositoryResponse> listener
@@ -277,6 +285,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                                     l -> blobStoreRepository.cleanup(
                                         repositoryStateId,
                                         snapshotsService.minCompatibleVersion(newState.nodes().getMinNodeVersion(), repositoryData, null),
+                                        remoteStoreLockManagerFactory,
                                         ActionListener.wrap(result -> after(null, result), e -> after(e, null))
                                     )
                                 )
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/package-info.java
new file mode 100644
index 0000000000000..1a9c0f2ce113b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/cleanup/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler for cleaning up a snapshot repository. */
+package org.opensearch.action.admin.cluster.repositories.cleanup;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryAction.java
index 3e6cbcbae8a8f..2031e4f7a716f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryAction.java
@@ -37,6 +37,8 @@
 
 /**
  * Unregister repository action
+ *
+ * @opensearch.internal
  */
 public class DeleteRepositoryAction extends ActionType<AcknowledgedResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequest.java
index 610b985eb0484..352a3772e039b 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -45,6 +45,8 @@
  * Unregister repository request.
  * <p>
  * The unregister repository command just unregisters the repository. No data is getting deleted from the repository.
+ *
+ * @opensearch.internal
  */
 public class DeleteRepositoryRequest extends AcknowledgedRequest<DeleteRepositoryRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequestBuilder.java
index 3a390dd1df2ab..ffef8d5b41979 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/DeleteRepositoryRequestBuilder.java
@@ -38,6 +38,8 @@
 
 /**
  * Builder for unregister repository request
+ *
+ * @opensearch.internal
  */
 public class DeleteRepositoryRequestBuilder extends AcknowledgedRequestBuilder<
     DeleteRepositoryRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java
index c7369cabbc75d..3d779befe474e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.action.admin.cluster.repositories.delete;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Transport action for unregister repository operation
+ *
+ * @opensearch.internal
  */
-public class TransportDeleteRepositoryAction extends TransportMasterNodeAction<DeleteRepositoryRequest, AcknowledgedResponse> {
+public class TransportDeleteRepositoryAction extends TransportClusterManagerNodeAction<DeleteRepositoryRequest, AcknowledgedResponse> {
 
     private final RepositoriesService repositoriesService;
 
@@ -93,7 +95,7 @@ protected ClusterBlockException checkBlock(DeleteRepositoryRequest request, Clus
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteRepositoryRequest request,
         ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/package-info.java
new file mode 100644
index 0000000000000..db9d5e7f8ceea
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler for deleting a snapshot repository. */
+package org.opensearch.action.admin.cluster.repositories.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesAction.java
index 86bc21ef8fd41..8d0fa4dc5010c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Get repositories action
+ *
+ * @opensearch.internal
  */
 public class GetRepositoriesAction extends ActionType<GetRepositoriesResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequest.java
index 02b42d82e6702..ac975e917e056 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequest.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.admin.cluster.repositories.get;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -44,8 +44,10 @@
 
 /**
  * Get repository request
+ *
+ * @opensearch.internal
  */
-public class GetRepositoriesRequest extends MasterNodeReadRequest<GetRepositoriesRequest> {
+public class GetRepositoriesRequest extends ClusterManagerNodeReadRequest<GetRepositoriesRequest> {
 
     private String[] repositories = Strings.EMPTY_ARRAY;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequestBuilder.java
index 8c4555ce54f1e..4b93aff4c25bc 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesRequestBuilder.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.cluster.repositories.get;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
 
 /**
  * Get repository request builder
+ *
+ * @opensearch.internal
  */
-public class GetRepositoriesRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+public class GetRepositoriesRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     GetRepositoriesRequest,
     GetRepositoriesResponse,
     GetRepositoriesRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesResponse.java
index ffb78f9622228..098a0e60142e7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/GetRepositoriesResponse.java
@@ -32,23 +32,25 @@
 
 package org.opensearch.action.admin.cluster.repositories.get;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Get repositories response
+ *
+ * @opensearch.internal
  */
 public class GetRepositoriesResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/TransportGetRepositoriesAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/TransportGetRepositoriesAction.java
index d3a66671b585b..c7d784dbc96e7 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/TransportGetRepositoriesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/TransportGetRepositoriesAction.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.action.admin.cluster.repositories.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -44,8 +43,9 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.repositories.RepositoryMissingException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -59,8 +59,10 @@
 
 /**
  * Transport action for get repositories operation
+ *
+ * @opensearch.internal
  */
-public class TransportGetRepositoriesAction extends TransportMasterNodeReadAction<GetRepositoriesRequest, GetRepositoriesResponse> {
+public class TransportGetRepositoriesAction extends TransportClusterManagerNodeReadAction<GetRepositoriesRequest, GetRepositoriesResponse> {
 
     @Inject
     public TransportGetRepositoriesAction(
@@ -97,7 +99,7 @@ protected ClusterBlockException checkBlock(GetRepositoriesRequest request, Clust
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final GetRepositoriesRequest request,
         ClusterState state,
         final ActionListener<GetRepositoriesResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/package-info.java
new file mode 100644
index 0000000000000..9f053ae11d8bc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler for getting a snapshot repository. */
+package org.opensearch.action.admin.cluster.repositories.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/package-info.java
new file mode 100644
index 0000000000000..75eb53cb11748
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Repository transport handlers. */
+package org.opensearch.action.admin.cluster.repositories;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryAction.java
index 35bcdb6444ed7..c2f90d869d873 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryAction.java
@@ -37,6 +37,8 @@
 
 /**
  * Register repository action
+ *
+ * @opensearch.internal
  */
 public class PutRepositoryAction extends ActionType<AcknowledgedResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
index a3561f6b3052a..582f73f335b49 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
@@ -32,28 +32,32 @@
 
 package org.opensearch.action.admin.cluster.repositories.put;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.cluster.crypto.CryptoSettings;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
-import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 
 /**
  * Register repository request.
  * <p>
  * Registers a repository with given name, type and settings. If the repository with the same name already
  * exists in the cluster, the new repository will replace the existing repository.
+ *
+ * @opensearch.internal
  */
 public class PutRepositoryRequest extends AcknowledgedRequest<PutRepositoryRequest> implements ToXContentObject {
 
@@ -65,12 +69,18 @@ public class PutRepositoryRequest extends AcknowledgedRequest<PutRepositoryReque
 
     private Settings settings = EMPTY_SETTINGS;
 
+    private CryptoSettings cryptoSettings;
+
     public PutRepositoryRequest(StreamInput in) throws IOException {
         super(in);
         name = in.readString();
         type = in.readString();
         settings = readSettingsFromStream(in);
         verify = in.readBoolean();
+
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            cryptoSettings = in.readOptionalWriteable(CryptoSettings::new);
+        }
     }
 
     public PutRepositoryRequest() {}
@@ -91,6 +101,9 @@ public ActionRequestValidationException validate() {
         if (type == null) {
             validationException = addValidationError("type is missing", validationException);
         }
+        if (cryptoSettings != null) {
+            validationException = cryptoSettings.validate();
+        }
         return validationException;
     }
 
@@ -162,11 +175,11 @@ public PutRepositoryRequest settings(Settings.Builder settings) {
      * Sets the repository settings.
      *
      * @param source repository settings in json or yaml format
-     * @param xContentType the content type of the source
+     * @param mediaType the content type of the source
      * @return this request
      */
-    public PutRepositoryRequest settings(String source, XContentType xContentType) {
-        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+    public PutRepositoryRequest settings(String source, final MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -205,6 +218,26 @@ public boolean verify() {
         return this.verify;
     }
 
+    /**
+     * Sets the repository crypto settings
+     *
+     * @param cryptoSettings repository crypto settings
+     * @return this request
+     */
+    public PutRepositoryRequest cryptoSettings(CryptoSettings cryptoSettings) {
+        this.cryptoSettings = cryptoSettings;
+        return this;
+    }
+
+    /**
+     * Returns repository encryption settings
+     *
+     * @return repository encryption settings
+     */
+    public CryptoSettings cryptoSettings() {
+        return cryptoSettings;
+    }
+
     /**
      * Parses repository definition.
      *
@@ -222,6 +255,14 @@ public PutRepositoryRequest source(Map<String, Object> repositoryDefinition) {
                 @SuppressWarnings("unchecked")
                 Map<String, Object> sub = (Map<String, Object>) entry.getValue();
                 settings(sub);
+            } else if (name.equals("crypto_settings")) {
+                if (!(entry.getValue() instanceof Map)) {
+                    throw new IllegalArgumentException("Malformed encryption_settings section, should include an inner object");
+                }
+                @SuppressWarnings("unchecked")
+                Map<String, Object> sub = (Map<String, Object>) entry.getValue();
+                CryptoSettings cryptoSettings = new CryptoSettings(sub);
+                cryptoSettings(cryptoSettings);
             }
         }
         return this;
@@ -234,6 +275,9 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeString(type);
         writeSettingsToStream(settings, out);
         out.writeBoolean(verify);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalWriteable(cryptoSettings);
+        }
     }
 
     @Override
@@ -247,6 +291,13 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.endObject();
 
         builder.field("verify", verify);
+
+        if (cryptoSettings != null) {
+            builder.startObject("crypto_settings");
+            cryptoSettings.toXContent(builder, params);
+            builder.endObject();
+        }
+
         builder.endObject();
         return builder;
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
index 09a33533c8889..cf649ee6b4cbf 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.action.admin.cluster.repositories.put;
 
+import org.opensearch.action.admin.cluster.crypto.CryptoSettings;
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
@@ -42,6 +43,8 @@
 
 /**
  * Register repository request builder
+ *
+ * @opensearch.internal
  */
 public class PutRepositoryRequestBuilder extends AcknowledgedRequestBuilder<
     PutRepositoryRequest,
@@ -139,4 +142,15 @@ public PutRepositoryRequestBuilder setVerify(boolean verify) {
         request.verify(verify);
         return this;
     }
+
+    /**
+     * Sets the repository encryption settings
+     *
+     * @param cryptoSettings repository crypto settings builder
+     * @return this builder
+     */
+    public PutRepositoryRequestBuilder setEncryptionSettings(CryptoSettings cryptoSettings) {
+        request.cryptoSettings(cryptoSettings);
+        return this;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/TransportPutRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/TransportPutRepositoryAction.java
index c91f492209bdd..1eadab6b1352e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/TransportPutRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/TransportPutRepositoryAction.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.action.admin.cluster.repositories.put;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Transport action for register repository operation
+ *
+ * @opensearch.internal
  */
-public class TransportPutRepositoryAction extends TransportMasterNodeAction<PutRepositoryRequest, AcknowledgedResponse> {
+public class TransportPutRepositoryAction extends TransportClusterManagerNodeAction<PutRepositoryRequest, AcknowledgedResponse> {
 
     private final RepositoriesService repositoriesService;
 
@@ -93,12 +95,12 @@ protected ClusterBlockException checkBlock(PutRepositoryRequest request, Cluster
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutRepositoryRequest request,
         ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
     ) {
-        repositoriesService.registerRepository(
+        repositoriesService.registerOrUpdateRepository(
             request,
             ActionListener.delegateFailure(
                 listener,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/package-info.java
new file mode 100644
index 0000000000000..e5b6305416174
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/put/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handlers for putting a new snapshot repository */
+package org.opensearch.action.admin.cluster.repositories.put;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java
index 2c727ece7f130..d717d2200902f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.action.admin.cluster.repositories.verify;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -42,7 +41,8 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Transport action for verifying repository operation
+ *
+ * @opensearch.internal
  */
-public class TransportVerifyRepositoryAction extends TransportMasterNodeAction<VerifyRepositoryRequest, VerifyRepositoryResponse> {
+public class TransportVerifyRepositoryAction extends TransportClusterManagerNodeAction<VerifyRepositoryRequest, VerifyRepositoryResponse> {
 
     private final RepositoriesService repositoriesService;
 
@@ -93,7 +95,7 @@ protected ClusterBlockException checkBlock(VerifyRepositoryRequest request, Clus
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final VerifyRepositoryRequest request,
         ClusterState state,
         final ActionListener<VerifyRepositoryResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryAction.java
index 98239c9da0f80..10b82f2d5c0f0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Verify repository action
+ *
+ * @opensearch.internal
  */
 public class VerifyRepositoryAction extends ActionType<VerifyRepositoryResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequest.java
index 12788a421c75f..b84161e716f5d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -43,6 +43,8 @@
 
 /**
  * Verify repository request.
+ *
+ * @opensearch.internal
  */
 public class VerifyRepositoryRequest extends AcknowledgedRequest<VerifyRepositoryRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequestBuilder.java
index db01ac2268b9a..c405fb9bc12cd 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryRequestBuilder.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.action.admin.cluster.repositories.verify;
 
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
 /**
  * Builder for verify repository request
+ *
+ * @opensearch.internal
  */
-public class VerifyRepositoryRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class VerifyRepositoryRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     VerifyRepositoryRequest,
     VerifyRepositoryResponse,
     VerifyRepositoryRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponse.java
index f31189f3073e0..d7af3478bdac3 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponse.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.action.admin.cluster.repositories.verify;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -52,12 +53,19 @@
 
 /**
  * Verify repository response
+ *
+ * @opensearch.internal
  */
 public class VerifyRepositoryResponse extends ActionResponse implements ToXContentObject {
 
     static final String NODES = "nodes";
     static final String NAME = "name";
 
+    /**
+     * Inner Node View
+     *
+     * @opensearch.internal
+     */
     public static class NodeView implements Writeable, ToXContentObject {
         private static final ObjectParser.NamedObjectParser<NodeView, Void> PARSER;
         static {
@@ -188,7 +196,7 @@ public static VerifyRepositoryResponse fromXContent(XContentParser parser) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/package-info.java
new file mode 100644
index 0000000000000..236e7a6b26369
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/repositories/verify/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler for verifying a snapshot repository. */
+package org.opensearch.action.admin.cluster.repositories.verify;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteAction.java
index f52169911e3a9..d6a09f47cbf12 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for rerouting allocation commands
+ *
+ * @opensearch.internal
+ */
 public class ClusterRerouteAction extends ActionType<ClusterRerouteResponse> {
 
     public static final ClusterRerouteAction INSTANCE = new ClusterRerouteAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequest.java
index ddef4f62c5298..a6addce14787d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequest.java
@@ -36,14 +36,16 @@
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Request to submit cluster reroute allocation commands
+ *
+ * @opensearch.internal
  */
 public class ClusterRerouteRequest extends AcknowledgedRequest<ClusterRerouteRequest> {
     private AllocationCommands commands = new AllocationCommands();
@@ -161,12 +163,12 @@ public boolean equals(Object obj) {
             && Objects.equals(explain, other.explain)
             && Objects.equals(timeout, other.timeout)
             && Objects.equals(retryFailed, other.retryFailed)
-            && Objects.equals(masterNodeTimeout, other.masterNodeTimeout);
+            && Objects.equals(clusterManagerNodeTimeout, other.clusterManagerNodeTimeout);
     }
 
     @Override
     public int hashCode() {
         // Override equals and hashCode for testing
-        return Objects.hash(commands, dryRun, explain, timeout, retryFailed, masterNodeTimeout);
+        return Objects.hash(commands, dryRun, explain, timeout, retryFailed, clusterManagerNodeTimeout);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestBuilder.java
index 8e0116bb3646e..01d52cb43320d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestBuilder.java
@@ -38,6 +38,8 @@
 
 /**
  * Builder for a cluster reroute request
+ *
+ * @opensearch.internal
  */
 public class ClusterRerouteRequestBuilder extends AcknowledgedRequestBuilder<
     ClusterRerouteRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponse.java
index da4cfb4333b3d..a62029218ca25 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponse.java
@@ -35,16 +35,18 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.allocation.RoutingExplanations;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Response returned after a cluster reroute request
+ *
+ * @opensearch.internal
  */
 public class ClusterRerouteResponse extends AcknowledgedResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/TransportClusterRerouteAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/TransportClusterRerouteAction.java
index c0e3d30fdb702..134583a56f489 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/TransportClusterRerouteAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/TransportClusterRerouteAction.java
@@ -36,13 +36,12 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresAction;
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresRequest;
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresResponse;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -54,13 +53,14 @@
 import org.opensearch.cluster.routing.allocation.command.AbstractAllocateAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommand;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -70,11 +70,17 @@
 import java.util.List;
 import java.util.Map;
 
-public class TransportClusterRerouteAction extends TransportMasterNodeAction<ClusterRerouteRequest, ClusterRerouteResponse> {
+/**
+ * Transport action for rerouting cluster allocation commands
+ *
+ * @opensearch.internal
+ */
+public class TransportClusterRerouteAction extends TransportClusterManagerNodeAction<ClusterRerouteRequest, ClusterRerouteResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportClusterRerouteAction.class);
 
     private final AllocationService allocationService;
+    private static ClusterManagerTaskThrottler.ThrottlingKey clusterRerouteTaskKey;
 
     @Inject
     public TransportClusterRerouteAction(
@@ -95,6 +101,8 @@ public TransportClusterRerouteAction(
             indexNameExpressionResolver
         );
         this.allocationService = allocationService;
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        clusterRerouteTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CLUSTER_REROUTE_API_KEY, true);
     }
 
     @Override
@@ -114,7 +122,7 @@ protected ClusterRerouteResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ClusterRerouteRequest request,
         final ClusterState state,
         final ActionListener<ClusterRerouteResponse> listener
@@ -143,12 +151,11 @@ private void verifyThenSubmitUpdate(
             IndicesShardStoresAction.NAME,
             new IndicesShardStoresRequest().indices(stalePrimaryAllocations.keySet().toArray(Strings.EMPTY_ARRAY)),
             new ActionListenerResponseHandler<>(ActionListener.wrap(response -> {
-                ImmutableOpenMap<String, ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>>> status = response
-                    .getStoreStatuses();
+                final Map<String, Map<Integer, List<IndicesShardStoresResponse.StoreStatus>>> status = response.getStoreStatuses();
                 Exception e = null;
                 for (Map.Entry<String, List<AbstractAllocateAllocationCommand>> entry : stalePrimaryAllocations.entrySet()) {
                     final String index = entry.getKey();
-                    final ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> indexStatus = status.get(index);
+                    final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> indexStatus = status.get(index);
                     if (indexStatus == null) {
                         // The index in the stale primary allocation request was green and hence filtered out by the store status
                         // request. We ignore it here since the relevant exception will be thrown by the reroute action later on.
@@ -209,6 +216,11 @@ private void submitStateUpdate(final ClusterRerouteRequest request, final Action
         );
     }
 
+    /**
+     * Inner Reroute Response Acknowledged the Cluster State Update
+     *
+     * @opensearch.internal
+     */
     static class ClusterRerouteResponseAckedClusterStateUpdateTask extends AckedClusterStateUpdateTask<ClusterRerouteResponse> {
 
         private final ClusterRerouteRequest request;
@@ -231,6 +243,11 @@ static class ClusterRerouteResponseAckedClusterStateUpdateTask extends AckedClus
             this.allocationService = allocationService;
         }
 
+        @Override
+        public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+            return clusterRerouteTaskKey;
+        }
+
         @Override
         protected ClusterRerouteResponse newResponse(boolean acknowledged) {
             return new ClusterRerouteResponse(acknowledged, clusterStateToSend, explanations);
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/reroute/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/package-info.java
new file mode 100644
index 0000000000000..af26371347c0d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/reroute/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster reroute transport handlers. */
+package org.opensearch.action.admin.cluster.reroute;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsRequest.java
index b490f172ce7ad..a56e7bbcfbfa4 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsRequest.java
@@ -33,14 +33,16 @@
 package org.opensearch.action.admin.cluster.settings;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 
 /**
  * This request is specific to the REST client. {@link ClusterStateRequest}
  * is used on the transport layer.
+ *
+ * @opensearch.internal
  */
-public class ClusterGetSettingsRequest extends MasterNodeReadRequest<ClusterGetSettingsRequest> {
+public class ClusterGetSettingsRequest extends ClusterManagerNodeReadRequest<ClusterGetSettingsRequest> {
     private boolean includeDefaults = false;
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponse.java
index 95c148e9fe5d3..6be255696251f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponse.java
@@ -32,26 +32,29 @@
 
 package org.opensearch.action.admin.cluster.settings;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * This response is specific to the REST client. {@link ClusterStateResponse}
  * is used on the transport layer.
+ *
+ * @opensearch.internal
  */
 public class ClusterGetSettingsResponse extends ActionResponse implements ToXContentObject {
 
@@ -173,7 +176,7 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsAction.java
index dcc7c786cc3ae..12134e6936ddb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for updating cluster settings
+ *
+ * @opensearch.internal
+ */
 public class ClusterUpdateSettingsAction extends ActionType<ClusterUpdateSettingsResponse> {
 
     public static final ClusterUpdateSettingsAction INSTANCE = new ClusterUpdateSettingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
index 12cce7cf74efa..6b62a5edd8c28 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
@@ -34,26 +34,28 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
-import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 
 /**
  * Request for an update cluster settings action
+ *
+ * @opensearch.internal
  */
 public class ClusterUpdateSettingsRequest extends AcknowledgedRequest<ClusterUpdateSettingsRequest> implements ToXContentObject {
 
@@ -118,8 +120,8 @@ public ClusterUpdateSettingsRequest transientSettings(Settings.Builder settings)
     /**
      * Sets the source containing the transient settings to be updated. They will not survive a full cluster restart
      */
-    public ClusterUpdateSettingsRequest transientSettings(String source, XContentType xContentType) {
-        this.transientSettings = Settings.builder().loadFromSource(source, xContentType).build();
+    public ClusterUpdateSettingsRequest transientSettings(String source, final MediaType mediaType) {
+        this.transientSettings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -150,8 +152,8 @@ public ClusterUpdateSettingsRequest persistentSettings(Settings.Builder settings
     /**
      * Sets the source containing the persistent settings to be updated. They will get applied cross restarts
      */
-    public ClusterUpdateSettingsRequest persistentSettings(String source, XContentType xContentType) {
-        this.persistentSettings = Settings.builder().loadFromSource(source, xContentType).build();
+    public ClusterUpdateSettingsRequest persistentSettings(String source, final MediaType mediaType) {
+        this.persistentSettings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
index 1ec7bd6cfb47d..4d08c94f78b6a 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
@@ -41,6 +41,8 @@
 
 /**
  * Builder for a cluster update settings request
+ *
+ * @opensearch.internal
  */
 public class ClusterUpdateSettingsRequestBuilder extends AcknowledgedRequestBuilder<
     ClusterUpdateSettingsRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponse.java
index 91955126dd745..1c543260f7aee 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponse.java
@@ -33,21 +33,23 @@
 package org.opensearch.action.admin.cluster.settings;
 
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A response for a cluster update settings action.
+ *
+ * @opensearch.internal
  */
 public class ClusterUpdateSettingsResponse extends AcknowledgedResponse {
 
@@ -57,7 +59,9 @@ public class ClusterUpdateSettingsResponse extends AcknowledgedResponse {
     private static final ConstructingObjectParser<ClusterUpdateSettingsResponse, Void> PARSER = new ConstructingObjectParser<>(
         "cluster_update_settings_response",
         true,
-        args -> { return new ClusterUpdateSettingsResponse((boolean) args[0], (Settings) args[1], (Settings) args[2]); }
+        args -> {
+            return new ClusterUpdateSettingsResponse((boolean) args[0], (Settings) args[1], (Settings) args[2]);
+        }
     );
     static {
         declareAcknowledgedField(PARSER);
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/SettingsUpdater.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/SettingsUpdater.java
index bcc95c01b4189..c7030764a5b47 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/SettingsUpdater.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/SettingsUpdater.java
@@ -50,6 +50,8 @@
 /**
  * Updates transient and persistent cluster state settings if there are any changes
  * due to the update.
+ *
+ * @opensearch.internal
  */
 final class SettingsUpdater {
     final Settings.Builder transientUpdates = Settings.builder();
@@ -136,6 +138,13 @@ synchronized ClusterState updateSettings(
             } else {
                 blocks.removeGlobalBlock(Metadata.CLUSTER_READ_ONLY_ALLOW_DELETE_BLOCK);
             }
+            boolean createIndexBlocked = Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.get(metadata.persistentSettings())
+                || Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.get(metadata.transientSettings());
+            if (createIndexBlocked) {
+                blocks.addGlobalBlock(Metadata.CLUSTER_CREATE_INDEX_BLOCK);
+            } else {
+                blocks.removeGlobalBlock(Metadata.CLUSTER_CREATE_INDEX_BLOCK);
+            }
             clusterState = builder(currentState).metadata(metadata).blocks(blocks).build();
         } else {
             clusterState = currentState;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/TransportClusterUpdateSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/TransportClusterUpdateSettingsAction.java
index 6d479431e1a94..2f3cc77b05550 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/settings/TransportClusterUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/TransportClusterUpdateSettingsAction.java
@@ -36,9 +36,8 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -47,18 +46,26 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportClusterUpdateSettingsAction extends TransportMasterNodeAction<
+/**
+ * Transport action for updating cluster settings
+ *
+ * @opensearch.internal
+ */
+public class TransportClusterUpdateSettingsAction extends TransportClusterManagerNodeAction<
     ClusterUpdateSettingsRequest,
     ClusterUpdateSettingsResponse> {
 
@@ -68,6 +75,8 @@ public class TransportClusterUpdateSettingsAction extends TransportMasterNodeAct
 
     private final ClusterSettings clusterSettings;
 
+    private final ClusterManagerTaskThrottler.ThrottlingKey clusterUpdateSettingTaskKey;
+
     @Inject
     public TransportClusterUpdateSettingsAction(
         TransportService transportService,
@@ -90,6 +99,10 @@ public TransportClusterUpdateSettingsAction(
         );
         this.allocationService = allocationService;
         this.clusterSettings = clusterSettings;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        clusterUpdateSettingTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CLUSTER_UPDATE_SETTINGS_KEY, true);
+
     }
 
     @Override
@@ -119,7 +132,7 @@ protected ClusterUpdateSettingsResponse read(StreamInput in) throws IOException
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ClusterUpdateSettingsRequest request,
         final ClusterState state,
         final ActionListener<ClusterUpdateSettingsResponse> listener
@@ -131,6 +144,11 @@ protected void masterOperation(
 
                 private volatile boolean changed = false;
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return clusterUpdateSettingTaskKey;
+                }
+
                 @Override
                 protected ClusterUpdateSettingsResponse newResponse(boolean acknowledged) {
                     return new ClusterUpdateSettingsResponse(acknowledged, updater.getTransientUpdates(), updater.getPersistentUpdate());
@@ -155,11 +173,11 @@ public void onAckTimeout() {
                 }
 
                 private void reroute(final boolean updateSettingsAcked) {
-                    // We're about to send a second update task, so we need to check if we're still the elected master
-                    // For example the minimum_master_node could have been breached and we're no longer elected master,
+                    // We're about to send a second update task, so we need to check if we're still the elected cluster-manager
+                    // For example the minimum_master_node could have been breached and we're no longer elected cluster-manager,
                     // so we should *not* execute the reroute.
-                    if (!clusterService.state().nodes().isLocalNodeElectedMaster()) {
-                        logger.debug("Skipping reroute after cluster update settings, because node is no longer master");
+                    if (!clusterService.state().nodes().isLocalNodeElectedClusterManager()) {
+                        logger.debug("Skipping reroute after cluster update settings, because node is no longer cluster-manager");
                         listener.onResponse(
                             new ClusterUpdateSettingsResponse(
                                 updateSettingsAcked,
@@ -196,9 +214,9 @@ protected ClusterUpdateSettingsResponse newResponse(boolean acknowledged) {
                             }
 
                             @Override
-                            public void onNoLongerMaster(String source) {
+                            public void onNoLongerClusterManager(String source) {
                                 logger.debug(
-                                    "failed to preform reroute after cluster settings were updated - current node is no longer a master"
+                                    "failed to preform reroute after cluster settings were updated - current node is no longer a cluster-manager"
                                 );
                                 listener.onResponse(
                                     new ClusterUpdateSettingsResponse(
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/settings/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/settings/package-info.java
new file mode 100644
index 0000000000000..a532b3e9f4158
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/settings/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster settings transport handlers. */
+package org.opensearch.action.admin.cluster.settings;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsAction.java
index 9d6b0f9677a95..176d52d3eeaab 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for searching shards
+ *
+ * @opensearch.internal
+ */
 public class ClusterSearchShardsAction extends ActionType<ClusterSearchShardsResponse> {
 
     public static final ClusterSearchShardsAction INSTANCE = new ClusterSearchShardsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsGroup.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsGroup.java
index 660c4629f6db2..84e9554932864 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsGroup.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsGroup.java
@@ -33,15 +33,20 @@
 package org.opensearch.action.admin.cluster.shards;
 
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Transport action for searching shard groups
+ *
+ * @opensearch.internal
+ */
 public class ClusterSearchShardsGroup implements Writeable, ToXContentObject {
 
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequest.java
index 7ae4a70d6bd36..7ddb945ad911e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequest.java
@@ -35,16 +35,23 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
-public class ClusterSearchShardsRequest extends MasterNodeReadRequest<ClusterSearchShardsRequest> implements IndicesRequest.Replaceable {
+/**
+ * Transport request for searching shards
+ *
+ * @opensearch.internal
+ */
+public class ClusterSearchShardsRequest extends ClusterManagerNodeReadRequest<ClusterSearchShardsRequest>
+    implements
+        IndicesRequest.Replaceable {
 
     private String[] indices = Strings.EMPTY_ARRAY;
     @Nullable
@@ -145,7 +152,8 @@ public ClusterSearchShardsRequest routing(String... routings) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public ClusterSearchShardsRequest preference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestBuilder.java
index ae5c22a1c57a7..674a2c2c36221 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestBuilder.java
@@ -33,10 +33,15 @@
 package org.opensearch.action.admin.cluster.shards;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class ClusterSearchShardsRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for searching shards
+ *
+ * @opensearch.internal
+ */
+public class ClusterSearchShardsRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     ClusterSearchShardsRequest,
     ClusterSearchShardsResponse,
     ClusterSearchShardsRequestBuilder> {
@@ -71,7 +76,8 @@ public ClusterSearchShardsRequestBuilder setRouting(String... routing) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public ClusterSearchShardsRequestBuilder setPreference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java
index 1381a39664a49..2b24d870219bb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.action.admin.cluster.shards;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.internal.AliasFilter;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Transport response for searching shards
+ *
+ * @opensearch.internal
+ */
 public class ClusterSearchShardsResponse extends ActionResponse implements ToXContentObject {
 
     private final ClusterSearchShardsGroup[] groups;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java
index 37a556216c2c9..a2a65b6400c97 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.action.admin.cluster.shards;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -45,8 +44,9 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.threadpool.ThreadPool;
@@ -58,7 +58,12 @@
 import java.util.Map;
 import java.util.Set;
 
-public class TransportClusterSearchShardsAction extends TransportMasterNodeReadAction<
+/**
+ * Transport action for searching shards
+ *
+ * @opensearch.internal
+ */
+public class TransportClusterSearchShardsAction extends TransportClusterManagerNodeReadAction<
     ClusterSearchShardsRequest,
     ClusterSearchShardsResponse> {
 
@@ -103,7 +108,7 @@ protected ClusterSearchShardsResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ClusterSearchShardsRequest request,
         final ClusterState state,
         final ActionListener<ClusterSearchShardsResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/package-info.java
new file mode 100644
index 0000000000000..94866d102ac15
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Search Shards transport handlers. */
+package org.opensearch.action.admin.cluster.shards;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingAction.java
new file mode 100644
index 0000000000000..aa438cd31b934
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action to delete weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterDeleteWeightedRoutingAction extends ActionType<ClusterDeleteWeightedRoutingResponse> {
+    public static final ClusterDeleteWeightedRoutingAction INSTANCE = new ClusterDeleteWeightedRoutingAction();
+    public static final String NAME = "cluster:admin/routing/awareness/weights/delete";
+
+    private ClusterDeleteWeightedRoutingAction() {
+        super(NAME, ClusterDeleteWeightedRoutingResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequest.java
new file mode 100644
index 0000000000000..7f69fe9fe3c72
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequest.java
@@ -0,0 +1,149 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchGenerationException;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Request to delete weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterDeleteWeightedRoutingRequest extends ClusterManagerNodeRequest<ClusterDeleteWeightedRoutingRequest> {
+    private static final Logger logger = LogManager.getLogger(ClusterDeleteWeightedRoutingRequest.class);
+
+    private long version;
+    private String awarenessAttribute;
+
+    public void setVersion(long version) {
+        this.version = version;
+    }
+
+    ClusterDeleteWeightedRoutingRequest() {
+        this.version = WeightedRoutingMetadata.VERSION_UNSET_VALUE;
+    }
+
+    public ClusterDeleteWeightedRoutingRequest(StreamInput in) throws IOException {
+        super(in);
+        version = in.readLong();
+        if (in.available() != 0) {
+            awarenessAttribute = in.readString();
+        }
+    }
+
+    public long getVersion() {
+        return version;
+    }
+
+    public String getAwarenessAttribute() {
+        return awarenessAttribute;
+    }
+
+    public void setAwarenessAttribute(String awarenessAttribute) {
+        this.awarenessAttribute = awarenessAttribute;
+    }
+
+    public ClusterDeleteWeightedRoutingRequest(String awarenessAttribute) {
+        this.awarenessAttribute = awarenessAttribute;
+        this.version = WeightedRoutingMetadata.VERSION_UNSET_VALUE;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+
+    /**
+     * @param source weights definition from request body
+     * @return this request
+     */
+    public ClusterDeleteWeightedRoutingRequest source(Map<String, String> source) {
+        try {
+            if (source.isEmpty()) {
+                throw new OpenSearchParseException(("Empty request body"));
+            }
+            XContentBuilder builder = XContentFactory.jsonBuilder();
+            builder.map(source);
+            setRequestBody(BytesReference.bytes(builder), builder.contentType());
+        } catch (IOException e) {
+            throw new OpenSearchGenerationException("Failed to generate [" + source + "]", e);
+        }
+        return this;
+    }
+
+    private void setRequestBody(BytesReference source, MediaType contentType) {
+        try (
+            XContentParser parser = XContentHelper.createParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+                source,
+                contentType
+            )
+        ) {
+            String versionAttr = null;
+            XContentParser.Token token;
+            // move to the first alias
+            parser.nextToken();
+            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    String fieldName = parser.currentName();
+                    if (fieldName != null && fieldName.equals(WeightedRoutingMetadata.VERSION)) {
+                        versionAttr = parser.currentName();
+                    } else {
+                        throw new OpenSearchParseException(
+                            "failed to parse delete weighted routing request body [{}], unknown type",
+                            fieldName
+                        );
+                    }
+                } else if (token == XContentParser.Token.VALUE_STRING) {
+                    if (versionAttr != null && versionAttr.equals(WeightedRoutingMetadata.VERSION)) {
+                        this.version = Long.parseLong(parser.text());
+                    }
+                } else {
+                    throw new OpenSearchParseException("failed to parse delete weighted routing request body");
+                }
+            }
+        } catch (IOException e) {
+            logger.error("error while parsing delete request for weighted routing request object", e);
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeLong(version);
+        if (awarenessAttribute != null) {
+            out.writeString(awarenessAttribute);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "ClusterDeleteWeightedRoutingRequest{" + "version= " + version + "awarenessAttribute=" + awarenessAttribute + "}";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequestBuilder.java
new file mode 100644
index 0000000000000..bb34fea589534
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingRequestBuilder.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
+
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+
+/**
+ * Request builder to delete weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterDeleteWeightedRoutingRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
+    ClusterDeleteWeightedRoutingRequest,
+    ClusterDeleteWeightedRoutingResponse,
+    ClusterDeleteWeightedRoutingRequestBuilder> {
+
+    public ClusterDeleteWeightedRoutingRequestBuilder(OpenSearchClient client, ClusterDeleteWeightedRoutingAction action) {
+        super(client, action, new ClusterDeleteWeightedRoutingRequest());
+    }
+
+    public ClusterDeleteWeightedRoutingRequestBuilder setVersion(long version) {
+        request.setVersion(version);
+        return this;
+    }
+
+    public ClusterDeleteWeightedRoutingRequestBuilder setAwarenessAttribute(String attribute) {
+        request.setAwarenessAttribute(attribute);
+        return this;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingResponse.java
new file mode 100644
index 0000000000000..2a417e9f4287f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/ClusterDeleteWeightedRoutingResponse.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
+
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Response from deleting weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterDeleteWeightedRoutingResponse extends AcknowledgedResponse {
+
+    ClusterDeleteWeightedRoutingResponse(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public ClusterDeleteWeightedRoutingResponse(boolean acknowledged) {
+        super(acknowledged);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/TransportDeleteWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/TransportDeleteWeightedRoutingAction.java
new file mode 100644
index 0000000000000..cea85ebf588bd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/TransportDeleteWeightedRoutingAction.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.WeightedRoutingService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for deleting weights for weighted round-robin search routing policy
+ *
+ * @opensearch.internal
+ */
+public class TransportDeleteWeightedRoutingAction extends TransportClusterManagerNodeAction<
+    ClusterDeleteWeightedRoutingRequest,
+    ClusterDeleteWeightedRoutingResponse> {
+
+    private static final Logger logger = LogManager.getLogger(TransportDeleteWeightedRoutingAction.class);
+
+    private final WeightedRoutingService weightedRoutingService;
+
+    @Inject
+    public TransportDeleteWeightedRoutingAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        WeightedRoutingService weightedRoutingService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            ClusterDeleteWeightedRoutingAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            ClusterDeleteWeightedRoutingRequest::new,
+            indexNameExpressionResolver
+        );
+        this.weightedRoutingService = weightedRoutingService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected ClusterDeleteWeightedRoutingResponse read(StreamInput in) throws IOException {
+        return new ClusterDeleteWeightedRoutingResponse(in);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(ClusterDeleteWeightedRoutingRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        ClusterDeleteWeightedRoutingRequest request,
+        ClusterState state,
+        ActionListener<ClusterDeleteWeightedRoutingResponse> listener
+    ) throws Exception {
+        weightedRoutingService.deleteWeightedRoutingMetadata(request, listener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/package-info.java
new file mode 100644
index 0000000000000..d24c88ec674f3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** delete weighted-round robin shard routing weights. */
+package org.opensearch.action.admin.cluster.shards.routing.weighted.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingAction.java
new file mode 100644
index 0000000000000..7662b7cc6fcc8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action to get weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterGetWeightedRoutingAction extends ActionType<ClusterGetWeightedRoutingResponse> {
+    public static final ClusterGetWeightedRoutingAction INSTANCE = new ClusterGetWeightedRoutingAction();
+    public static final String NAME = "cluster:admin/routing/awareness/weights/get";
+
+    private ClusterGetWeightedRoutingAction() {
+        super(NAME, ClusterGetWeightedRoutingResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequest.java
new file mode 100644
index 0000000000000..7dcec15c750fc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequest.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Request to get weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterGetWeightedRoutingRequest extends ClusterManagerNodeReadRequest<ClusterGetWeightedRoutingRequest> {
+
+    String awarenessAttribute;
+
+    public String getAwarenessAttribute() {
+        return awarenessAttribute;
+    }
+
+    public void setAwarenessAttribute(String awarenessAttribute) {
+        this.awarenessAttribute = awarenessAttribute;
+    }
+
+    public ClusterGetWeightedRoutingRequest(String awarenessAttribute) {
+        this.awarenessAttribute = awarenessAttribute;
+    }
+
+    public ClusterGetWeightedRoutingRequest() {}
+
+    public ClusterGetWeightedRoutingRequest(StreamInput in) throws IOException {
+        super(in);
+        awarenessAttribute = in.readString();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(awarenessAttribute);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (awarenessAttribute == null || awarenessAttribute.isEmpty()) {
+            validationException = addValidationError("Awareness attribute is missing", validationException);
+        }
+        return validationException;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequestBuilder.java
new file mode 100644
index 0000000000000..82f4c1106461d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingRequestBuilder.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
+
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+
+/**
+ * Request builder to get weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterGetWeightedRoutingRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
+    ClusterGetWeightedRoutingRequest,
+    ClusterGetWeightedRoutingResponse,
+    ClusterGetWeightedRoutingRequestBuilder> {
+
+    public ClusterGetWeightedRoutingRequestBuilder(OpenSearchClient client, ClusterGetWeightedRoutingAction action) {
+        super(client, action, new ClusterGetWeightedRoutingRequest());
+    }
+
+    public ClusterGetWeightedRoutingRequestBuilder setRequestLocal(boolean local) {
+        request.local(local);
+        return this;
+    }
+
+    public ClusterGetWeightedRoutingRequestBuilder setAwarenessAttribute(String attribute) {
+        request.setAwarenessAttribute(attribute);
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingResponse.java
new file mode 100644
index 0000000000000..5ef14d0e00c49
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/ClusterGetWeightedRoutingResponse.java
@@ -0,0 +1,186 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * Response from fetching weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterGetWeightedRoutingResponse extends ActionResponse implements ToXContentObject {
+
+    private static final String WEIGHTS = "weights";
+    private long version;
+    private final Boolean discoveredClusterManager;
+
+    private static final String DISCOVERED_CLUSTER_MANAGER = "discovered_cluster_manager";
+
+    public WeightedRouting getWeightedRouting() {
+        return weightedRouting;
+    }
+
+    private final WeightedRouting weightedRouting;
+
+    public long getVersion() {
+        return version;
+    }
+
+    public Boolean getDiscoveredClusterManager() {
+        return discoveredClusterManager;
+    }
+
+    ClusterGetWeightedRoutingResponse() {
+        this.weightedRouting = null;
+        this.discoveredClusterManager = null;
+    }
+
+    public ClusterGetWeightedRoutingResponse(WeightedRouting weightedRouting, Boolean discoveredClusterManager, long version) {
+        this.discoveredClusterManager = discoveredClusterManager;
+        this.weightedRouting = weightedRouting;
+        this.version = version;
+    }
+
+    ClusterGetWeightedRoutingResponse(StreamInput in) throws IOException {
+        if (in.available() != 0) {
+            this.weightedRouting = new WeightedRouting(in);
+            this.version = in.readLong();
+            this.discoveredClusterManager = in.readOptionalBoolean();
+        } else {
+            this.weightedRouting = null;
+            this.discoveredClusterManager = null;
+        }
+    }
+
+    /**
+     * List of weights to return
+     *
+     * @return list or weights
+     */
+    public WeightedRouting weights() {
+        return this.weightedRouting;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        if (weightedRouting != null) {
+            weightedRouting.writeTo(out);
+            out.writeLong(version);
+        }
+        if (discoveredClusterManager != null) {
+            out.writeOptionalBoolean(discoveredClusterManager);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (this.weightedRouting != null) {
+            builder.startObject(WEIGHTS);
+            for (Map.Entry<String, Double> entry : weightedRouting.weights().entrySet()) {
+                builder.field(entry.getKey(), entry.getValue().toString());
+            }
+
+            builder.endObject();
+            builder.field(WeightedRoutingMetadata.VERSION, version);
+            if (discoveredClusterManager != null) {
+                builder.field(DISCOVERED_CLUSTER_MANAGER, discoveredClusterManager);
+            }
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    public static ClusterGetWeightedRoutingResponse fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        XContentParser.Token token;
+        String attrKey = null, attrValue;
+        Boolean discoveredClusterManager = null;
+        Map<String, Double> weights = new HashMap<>();
+        long version = WeightedRoutingMetadata.VERSION_UNSET_VALUE;
+        String weightsAttr;
+        String fieldName = null;
+
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                fieldName = parser.currentName();
+                if (fieldName != null
+                    && (fieldName.equals(WeightedRoutingMetadata.VERSION) || fieldName.equals(DISCOVERED_CLUSTER_MANAGER))) {
+                    continue;
+                } else if (fieldName != null && fieldName.equals(WEIGHTS)) {
+                    weightsAttr = parser.currentName();
+                } else {
+                    throw new OpenSearchParseException("failed to parse weighted routing request object", fieldName);
+                }
+                if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                    throw new OpenSearchParseException(
+                        "failed to parse weighted routing request object [{}], expected object",
+                        weightsAttr
+                    );
+                }
+
+                while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                    if (token == XContentParser.Token.FIELD_NAME) {
+                        attrKey = parser.currentName();
+                    } else if (token == XContentParser.Token.VALUE_STRING) {
+                        attrValue = parser.text();
+                        if (attrKey != null) {
+                            weights.put(attrKey, Double.parseDouble(attrValue));
+                        }
+                    } else {
+                        throw new OpenSearchParseException("failed to parse weighted routing request attribute [{}]", attrKey);
+                    }
+                }
+            } else if (token == XContentParser.Token.VALUE_NUMBER
+                && fieldName != null
+                && fieldName.equals(WeightedRoutingMetadata.VERSION)) {
+                    version = parser.longValue();
+
+                } else if (token == XContentParser.Token.VALUE_BOOLEAN
+                    && fieldName != null
+                    && fieldName.equals(DISCOVERED_CLUSTER_MANAGER)) {
+                        discoveredClusterManager = Boolean.parseBoolean(parser.text());
+                    } else {
+                        throw new OpenSearchParseException("failed to parse weighted routing request");
+                    }
+        }
+
+        WeightedRouting weightedRouting = new WeightedRouting("", weights);
+        return new ClusterGetWeightedRoutingResponse(weightedRouting, discoveredClusterManager, version);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ClusterGetWeightedRoutingResponse that = (ClusterGetWeightedRoutingResponse) o;
+        return weightedRouting.equals(that.weightedRouting) && discoveredClusterManager.equals(that.discoveredClusterManager);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(weightedRouting, discoveredClusterManager);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/TransportGetWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/TransportGetWeightedRoutingAction.java
new file mode 100644
index 0000000000000..50368d85e0011
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/TransportGetWeightedRoutingAction.java
@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.routing.WeightedRoutingService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for getting weights for weighted round-robin search routing policy
+ *
+ * @opensearch.internal
+ */
+public class TransportGetWeightedRoutingAction extends TransportClusterManagerNodeReadAction<
+    ClusterGetWeightedRoutingRequest,
+    ClusterGetWeightedRoutingResponse> {
+    private static final Logger logger = LogManager.getLogger(TransportGetWeightedRoutingAction.class);
+    private final WeightedRoutingService weightedRoutingService;
+
+    @Inject
+    public TransportGetWeightedRoutingAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        WeightedRoutingService weightedRoutingService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            ClusterGetWeightedRoutingAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            ClusterGetWeightedRoutingRequest::new,
+            indexNameExpressionResolver
+        );
+        this.weightedRoutingService = weightedRoutingService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected ClusterGetWeightedRoutingResponse read(StreamInput in) throws IOException {
+        return new ClusterGetWeightedRoutingResponse(in);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(ClusterGetWeightedRoutingRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        final ClusterGetWeightedRoutingRequest request,
+        ClusterState state,
+        final ActionListener<ClusterGetWeightedRoutingResponse> listener
+    ) {
+        try {
+            weightedRoutingService.verifyAwarenessAttribute(request.getAwarenessAttribute());
+            WeightedRoutingMetadata weightedRoutingMetadata = state.metadata().custom(WeightedRoutingMetadata.TYPE);
+            ClusterGetWeightedRoutingResponse clusterGetWeightedRoutingResponse = new ClusterGetWeightedRoutingResponse();
+            if (weightedRoutingMetadata != null && weightedRoutingMetadata.getWeightedRouting() != null) {
+                WeightedRouting weightedRouting = weightedRoutingMetadata.getWeightedRouting();
+                clusterGetWeightedRoutingResponse = new ClusterGetWeightedRoutingResponse(
+                    weightedRouting,
+                    state.nodes().getClusterManagerNodeId() != null,
+                    weightedRoutingMetadata.getVersion()
+                );
+            }
+            listener.onResponse(clusterGetWeightedRoutingResponse);
+        } catch (Exception ex) {
+            listener.onFailure(ex);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/package-info.java
new file mode 100644
index 0000000000000..45e5b32b72e50
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** get weighted-round robin shard routing weights. */
+package org.opensearch.action.admin.cluster.shards.routing.weighted.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterAddWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterAddWeightedRoutingAction.java
new file mode 100644
index 0000000000000..65c5ccca71461
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterAddWeightedRoutingAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action to update weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public final class ClusterAddWeightedRoutingAction extends ActionType<ClusterPutWeightedRoutingResponse> {
+
+    public static final ClusterAddWeightedRoutingAction INSTANCE = new ClusterAddWeightedRoutingAction();
+    public static final String NAME = "cluster:admin/routing/awareness/weights/put";
+
+    private ClusterAddWeightedRoutingAction() {
+        super(NAME, ClusterPutWeightedRoutingResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequest.java
new file mode 100644
index 0000000000000..8e8432a384aa5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequest.java
@@ -0,0 +1,232 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchGenerationException;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Request to update weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterPutWeightedRoutingRequest extends ClusterManagerNodeRequest<ClusterPutWeightedRoutingRequest> {
+    private static final Logger logger = LogManager.getLogger(ClusterPutWeightedRoutingRequest.class);
+
+    private WeightedRouting weightedRouting;
+    private String attributeName;
+    private long version;
+
+    public void version(long version) {
+        this.version = version;
+    }
+
+    public long getVersion() {
+        return this.version;
+    }
+
+    public ClusterPutWeightedRoutingRequest() {}
+
+    public WeightedRouting getWeightedRouting() {
+        return weightedRouting;
+    }
+
+    public ClusterPutWeightedRoutingRequest setWeightedRouting(WeightedRouting weightedRouting) {
+        this.weightedRouting = weightedRouting;
+        return this;
+    }
+
+    public void attributeName(String attributeName) {
+        this.attributeName = attributeName;
+    }
+
+    public ClusterPutWeightedRoutingRequest(StreamInput in) throws IOException {
+        super(in);
+        weightedRouting = new WeightedRouting(in);
+        version = in.readLong();
+    }
+
+    public ClusterPutWeightedRoutingRequest(String attributeName) {
+        this.attributeName = attributeName;
+    }
+
+    public void setWeightedRouting(Map<String, Object> source) {
+        try {
+            if (source.isEmpty()) {
+                throw new OpenSearchParseException(("Empty request body"));
+            }
+            XContentBuilder builder = XContentFactory.jsonBuilder();
+            builder.map(source);
+            setWeightedRouting(BytesReference.bytes(builder), builder.contentType());
+        } catch (IOException e) {
+            throw new OpenSearchGenerationException("Failed to generate [" + source + "]", e);
+        }
+    }
+
+    public void setWeightedRouting(BytesReference source, MediaType contentType) {
+        try (
+            XContentParser parser = XContentHelper.createParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+                source,
+                contentType
+            )
+        ) {
+            String attrValue = null;
+            Map<String, Double> weights = new HashMap<>();
+            Double attrWeight = null;
+            XContentParser.Token token;
+            // move to the first alias
+            parser.nextToken();
+            String versionAttr = null;
+            String weightsAttr;
+            long version = WeightedRoutingMetadata.VERSION_UNSET_VALUE;
+
+            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    String fieldName = parser.currentName();
+                    if (fieldName != null && fieldName.equals(WeightedRoutingMetadata.VERSION)) {
+                        versionAttr = parser.currentName();
+                        continue;
+                    } else if (fieldName != null && fieldName.equals("weights")) {
+                        weightsAttr = parser.currentName();
+                    } else {
+                        throw new OpenSearchParseException("failed to parse weighted routing request object [{}]", fieldName);
+                    }
+                    if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                        throw new OpenSearchParseException(
+                            "failed to parse weighted routing request object  [{}], expected object",
+                            weightsAttr
+                        );
+                    }
+
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            attrValue = parser.currentName();
+                        } else if (token == XContentParser.Token.VALUE_STRING) {
+                            attrWeight = Double.parseDouble(parser.text());
+                            weights.put(attrValue, attrWeight);
+                        } else {
+                            throw new OpenSearchParseException(
+                                "failed to parse weighted routing request attribute [{}], " + "unknown type",
+                                attrWeight
+                            );
+                        }
+                    }
+                } else if (token == XContentParser.Token.VALUE_NUMBER) {
+                    if (versionAttr != null && versionAttr.equals(WeightedRoutingMetadata.VERSION)) {
+                        version = parser.longValue();
+                    }
+                } else {
+                    throw new OpenSearchParseException(
+                        "failed to parse weighted routing request " + "[{}], unknown " + "type",
+                        attributeName
+                    );
+                }
+            }
+            this.weightedRouting = new WeightedRouting(this.attributeName, weights);
+            this.version = version;
+        } catch (IOException e) {
+            logger.error("error while parsing put weighted routing request object", e);
+        }
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (weightedRouting == null) {
+            validationException = addValidationError("Weighted routing request object is null", validationException);
+        }
+        if (weightedRouting.attributeName() == null || weightedRouting.attributeName().isEmpty()) {
+            validationException = addValidationError("Attribute name is missing", validationException);
+        }
+        if (weightedRouting.weights() == null || weightedRouting.weights().isEmpty()) {
+            validationException = addValidationError("Weights are missing", validationException);
+        }
+        if (version == WeightedRoutingMetadata.VERSION_UNSET_VALUE) {
+            validationException = addValidationError("Version is missing", validationException);
+        }
+        int countValueWithZeroWeights = 0;
+        double weight;
+        try {
+            for (Object value : weightedRouting.weights().values()) {
+                if (value == null) {
+                    validationException = addValidationError(("Weight is null"), validationException);
+                } else {
+                    weight = Double.parseDouble(value.toString());
+                    countValueWithZeroWeights = (weight == 0) ? countValueWithZeroWeights + 1 : countValueWithZeroWeights;
+                }
+            }
+        } catch (NumberFormatException e) {
+            validationException = addValidationError(("Weight is not a number"), validationException);
+        }
+        // Returning validation exception here itself if it is not null, so we can have a descriptive message for the count check
+        if (validationException != null) {
+            return validationException;
+        }
+        if (countValueWithZeroWeights > weightedRouting.weights().size() / 2) {
+            validationException = addValidationError(
+                (String.format(
+                    Locale.ROOT,
+                    "There are too many attribute values [%s] given zero weight [%d]. Maximum expected number of routing weights having zero weight is [%d]",
+                    weightedRouting.weights().toString(),
+                    countValueWithZeroWeights,
+                    weightedRouting.weights().size() / 2
+                )),
+                null
+            );
+        }
+        return validationException;
+    }
+
+    /**
+     * @param source weights definition from request body
+     * @return this request
+     */
+    public ClusterPutWeightedRoutingRequest source(Map<String, Object> source) {
+        setWeightedRouting(source);
+        return this;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        weightedRouting.writeTo(out);
+        out.writeLong(version);
+    }
+
+    @Override
+    public String toString() {
+        return "ClusterPutWeightedRoutingRequest{" + "weightedRouting= " + weightedRouting.toString() + "version= " + version + "}";
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestBuilder.java
new file mode 100644
index 0000000000000..adfb2cf02f6d9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestBuilder.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.cluster.routing.WeightedRouting;
+
+/**
+ * Request builder to update weights for weighted round-robin shard routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterPutWeightedRoutingRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
+    ClusterPutWeightedRoutingRequest,
+    ClusterPutWeightedRoutingResponse,
+    ClusterPutWeightedRoutingRequestBuilder> {
+    public ClusterPutWeightedRoutingRequestBuilder(OpenSearchClient client, ClusterAddWeightedRoutingAction action) {
+        super(client, action, new ClusterPutWeightedRoutingRequest());
+    }
+
+    public ClusterPutWeightedRoutingRequestBuilder setWeightedRouting(WeightedRouting weightedRouting) {
+        request.setWeightedRouting(weightedRouting);
+        return this;
+    }
+
+    public ClusterPutWeightedRoutingRequestBuilder setVersion(long version) {
+        request.version(version);
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingResponse.java
new file mode 100644
index 0000000000000..cbf10aa74f8a2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingResponse.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+/**
+ * Response from updating weights for weighted round-robin search routing policy.
+ *
+ * @opensearch.internal
+ */
+public class ClusterPutWeightedRoutingResponse extends AcknowledgedResponse {
+    public ClusterPutWeightedRoutingResponse(boolean acknowledged) {
+        super(acknowledged);
+    }
+
+    public ClusterPutWeightedRoutingResponse(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/TransportAddWeightedRoutingAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/TransportAddWeightedRoutingAction.java
new file mode 100644
index 0000000000000..2f94842eaa39b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/TransportAddWeightedRoutingAction.java
@@ -0,0 +1,94 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.WeightedRoutingService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Transport action for updating weights for weighted round-robin search routing policy
+ *
+ * @opensearch.internal
+ */
+public class TransportAddWeightedRoutingAction extends TransportClusterManagerNodeAction<
+    ClusterPutWeightedRoutingRequest,
+    ClusterPutWeightedRoutingResponse> {
+
+    private final WeightedRoutingService weightedRoutingService;
+
+    @Inject
+    public TransportAddWeightedRoutingAction(
+        TransportService transportService,
+        ClusterService clusterService,
+        WeightedRoutingService weightedRoutingService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            ClusterAddWeightedRoutingAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            ClusterPutWeightedRoutingRequest::new,
+            indexNameExpressionResolver
+        );
+        this.weightedRoutingService = weightedRoutingService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected ClusterPutWeightedRoutingResponse read(StreamInput in) throws IOException {
+        return new ClusterPutWeightedRoutingResponse(in);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        ClusterPutWeightedRoutingRequest request,
+        ClusterState state,
+        ActionListener<ClusterPutWeightedRoutingResponse> listener
+    ) throws Exception {
+        try {
+            weightedRoutingService.verifyAwarenessAttribute(request.getWeightedRouting().attributeName());
+        } catch (ActionRequestValidationException ex) {
+            listener.onFailure(ex);
+            return;
+        }
+        weightedRoutingService.registerWeightedRoutingMetadata(
+            request,
+            ActionListener.delegateFailure(listener, (delegatedListener, response) -> {
+                delegatedListener.onResponse(new ClusterPutWeightedRoutingResponse(response.isAcknowledged()));
+            })
+        );
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(ClusterPutWeightedRoutingRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/package-info.java
new file mode 100644
index 0000000000000..4f18b220cd343
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** add/update weighted-round robin shard routing weights. */
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotAction.java
index 0ecc088ff462a..c6fe102544a7e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for cloning a snapshot
+ *
+ * @opensearch.internal
+ */
 public final class CloneSnapshotAction extends ActionType<AcknowledgedResponse> {
 
     public static final CloneSnapshotAction INSTANCE = new CloneSnapshotAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequest.java
index 58725c23b7fc5..694b13e37bb03 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequest.java
@@ -35,18 +35,27 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
-public class CloneSnapshotRequest extends MasterNodeRequest<CloneSnapshotRequest> implements IndicesRequest.Replaceable, ToXContentObject {
+/**
+ * Transport request for cloning a snapshot
+ *
+ * @opensearch.internal
+ */
+public class CloneSnapshotRequest extends ClusterManagerNodeRequest<CloneSnapshotRequest>
+    implements
+        IndicesRequest.Replaceable,
+        ToXContentObject {
 
     private final String repository;
 
@@ -178,6 +187,6 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequestBuilder.java
index ba6f7a61bdc8d..0f47d77d6a9d3 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/CloneSnapshotRequestBuilder.java
@@ -34,12 +34,17 @@
 
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
-public class CloneSnapshotRequestBuilder extends MasterNodeOperationRequestBuilder<
+/**
+ * Transport request builder for cloning a snapshot
+ *
+ * @opensearch.internal
+ */
+public class CloneSnapshotRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     CloneSnapshotRequest,
     AcknowledgedResponse,
     CloneSnapshotRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/TransportCloneSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/TransportCloneSnapshotAction.java
index 806cb4a82c3c5..54ef372609390 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/TransportCloneSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/TransportCloneSnapshotAction.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.action.admin.cluster.snapshots.clone;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Transport action for the clone snapshot operation.
+ *
+ * @opensearch.internal
  */
-public final class TransportCloneSnapshotAction extends TransportMasterNodeAction<CloneSnapshotRequest, AcknowledgedResponse> {
+public final class TransportCloneSnapshotAction extends TransportClusterManagerNodeAction<CloneSnapshotRequest, AcknowledgedResponse> {
 
     private final SnapshotsService snapshotsService;
 
@@ -88,7 +90,11 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(CloneSnapshotRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener) {
+    protected void clusterManagerOperation(
+        CloneSnapshotRequest request,
+        ClusterState state,
+        ActionListener<AcknowledgedResponse> listener
+    ) {
         snapshotsService.cloneSnapshot(request, ActionListener.map(listener, v -> new AcknowledgedResponse(true)));
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/package-info.java
new file mode 100644
index 0000000000000..14738fe5e95b4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/clone/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Clone Snapshot transport handler. */
+package org.opensearch.action.admin.cluster.snapshots.clone;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotAction.java
index 324a28027949f..fb95e311a9783 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Create snapshot action
+ *
+ * @opensearch.internal
  */
 public class CreateSnapshotAction extends ActionType<CreateSnapshotResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
index 438d2fd006e63..7796353d81c5b 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
@@ -37,16 +37,17 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -55,11 +56,11 @@
 import java.util.Objects;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
-import static org.opensearch.common.Strings.EMPTY_ARRAY;
 import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
 import static org.opensearch.common.xcontent.support.XContentMapValues.nodeBooleanValue;
+import static org.opensearch.core.common.Strings.EMPTY_ARRAY;
 import static org.opensearch.snapshots.SnapshotInfo.METADATA_FIELD_INTRODUCED;
 
 /**
@@ -71,12 +72,14 @@
  * <li>must not contain whitespace (tabs or spaces)</li>
  * <li>must not contain comma (',')</li>
  * <li>must not contain hash sign ('#')</li>
- * <li>must not start with underscore ('-')</li>
+ * <li>must not start with underscore ('_')</li>
  * <li>must be lowercase</li>
- * <li>must not contain invalid file name characters {@link org.opensearch.common.Strings#INVALID_FILENAME_CHARS} </li>
+ * <li>must not contain invalid file name characters {@link Strings#INVALID_FILENAME_CHARS} </li>
  * </ul>
+ *
+ * @opensearch.internal
  */
-public class CreateSnapshotRequest extends MasterNodeRequest<CreateSnapshotRequest>
+public class CreateSnapshotRequest extends ClusterManagerNodeRequest<CreateSnapshotRequest>
     implements
         IndicesRequest.Replaceable,
         ToXContentObject {
@@ -371,11 +374,11 @@ public CreateSnapshotRequest settings(Settings.Builder settings) {
      * See repository documentation for more information.
      *
      * @param source repository-specific snapshot settings
-     * @param xContentType the content type of the source
+     * @param mediaType the content type of the source
      * @return this request
      */
-    public CreateSnapshotRequest settings(String source, XContentType xContentType) {
-        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+    public CreateSnapshotRequest settings(String source, MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -389,9 +392,9 @@ public CreateSnapshotRequest settings(String source, XContentType xContentType)
      */
     public CreateSnapshotRequest settings(Map<String, Object> source) {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             builder.map(source);
-            settings(Strings.toString(builder), builder.contentType());
+            settings(builder.toString(), builder.contentType());
         } catch (IOException e) {
             throw new OpenSearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -519,7 +522,7 @@ public boolean equals(Object o) {
             && Arrays.equals(indices, that.indices)
             && Objects.equals(indicesOptions, that.indicesOptions)
             && Objects.equals(settings, that.settings)
-            && Objects.equals(masterNodeTimeout, that.masterNodeTimeout)
+            && Objects.equals(clusterManagerNodeTimeout, that.clusterManagerNodeTimeout)
             && Objects.equals(userMetadata, that.userMetadata);
     }
 
@@ -560,8 +563,8 @@ public String toString() {
             + includeGlobalState
             + ", waitForCompletion="
             + waitForCompletion
-            + ", masterNodeTimeout="
-            + masterNodeTimeout
+            + ", clusterManagerNodeTimeout="
+            + clusterManagerNodeTimeout
             + ", metadata="
             + userMetadata
             + '}';
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
index db30ce8295530..40d440419819c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.cluster.snapshots.create;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentType;
@@ -42,8 +42,10 @@
 
 /**
  * Create snapshot request builder
+ *
+ * @opensearch.internal
  */
-public class CreateSnapshotRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class CreateSnapshotRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     CreateSnapshotRequest,
     CreateSnapshotResponse,
     CreateSnapshotRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponse.java
index 9a92971a2a791..1517112b9b3e1 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponse.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.create;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotInfo.SnapshotInfoBuilder;
 
@@ -50,6 +50,8 @@
 
 /**
  * Create snapshot response
+ *
+ * @opensearch.internal
  */
 public class CreateSnapshotResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/TransportCreateSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/TransportCreateSnapshotAction.java
index 377fe03a9b030..768a6578c75fb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/TransportCreateSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/TransportCreateSnapshotAction.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.create;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -50,8 +50,10 @@
 
 /**
  * Transport action for create snapshot operation
+ *
+ * @opensearch.internal
  */
-public class TransportCreateSnapshotAction extends TransportMasterNodeAction<CreateSnapshotRequest, CreateSnapshotResponse> {
+public class TransportCreateSnapshotAction extends TransportClusterManagerNodeAction<CreateSnapshotRequest, CreateSnapshotResponse> {
     private final SnapshotsService snapshotsService;
 
     @Inject
@@ -96,7 +98,7 @@ protected ClusterBlockException checkBlock(CreateSnapshotRequest request, Cluste
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final CreateSnapshotRequest request,
         ClusterState state,
         final ActionListener<CreateSnapshotResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/package-info.java
new file mode 100644
index 0000000000000..58e1f4f9311ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/create/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Create Snapshot transport handler. */
+package org.opensearch.action.admin.cluster.snapshots.create;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotAction.java
index 4c577bd0bbce2..0b98a4b31fd53 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotAction.java
@@ -37,6 +37,8 @@
 
 /**
  * Delete snapshot action
+ *
+ * @opensearch.internal
  */
 public class DeleteSnapshotAction extends ActionType<AcknowledgedResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequest.java
index fe9dc4db626f7..1dfa5de8cc852 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequest.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.admin.cluster.snapshots.delete;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.snapshots.SnapshotsService;
 
 import java.io.IOException;
@@ -47,8 +47,10 @@
  * <p>
  * Delete snapshot request removes snapshots from the repository and cleans up all files that are associated with the snapshots.
  * All files that are shared with at least one other existing snapshot are left intact.
+ *
+ * @opensearch.internal
  */
-public class DeleteSnapshotRequest extends MasterNodeRequest<DeleteSnapshotRequest> {
+public class DeleteSnapshotRequest extends ClusterManagerNodeRequest<DeleteSnapshotRequest> {
 
     private String repository;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequestBuilder.java
index 951f86bafb7b1..1fa855265ffd4 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/DeleteSnapshotRequestBuilder.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.delete;
 
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
 /**
  * Delete snapshot request builder
+ *
+ * @opensearch.internal
  */
-public class DeleteSnapshotRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class DeleteSnapshotRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     DeleteSnapshotRequest,
     AcknowledgedResponse,
     DeleteSnapshotRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/TransportDeleteSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/TransportDeleteSnapshotAction.java
index 0781f01e9bc61..e8462e4d822f2 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/TransportDeleteSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/TransportDeleteSnapshotAction.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.action.admin.cluster.snapshots.delete;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Transport action for delete snapshot operation
+ *
+ * @opensearch.internal
  */
-public class TransportDeleteSnapshotAction extends TransportMasterNodeAction<DeleteSnapshotRequest, AcknowledgedResponse> {
+public class TransportDeleteSnapshotAction extends TransportClusterManagerNodeAction<DeleteSnapshotRequest, AcknowledgedResponse> {
     private final SnapshotsService snapshotsService;
 
     @Inject
@@ -93,7 +95,7 @@ protected ClusterBlockException checkBlock(DeleteSnapshotRequest request, Cluste
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteSnapshotRequest request,
         ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/package-info.java
new file mode 100644
index 0000000000000..5ad5e58ebe1fd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Delete Snapshot transport handler. */
+package org.opensearch.action.admin.cluster.snapshots.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsAction.java
index 22e3e859394c7..59d7969d04f86 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Get snapshots action
+ *
+ * @opensearch.internal
  */
 public class GetSnapshotsAction extends ActionType<GetSnapshotsResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequest.java
index 549e3cea70deb..8e2e2d3390058 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequest.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.admin.cluster.snapshots.get;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -44,8 +44,10 @@
 
 /**
  * Get snapshot request
+ *
+ * @opensearch.internal
  */
-public class GetSnapshotsRequest extends MasterNodeRequest<GetSnapshotsRequest> {
+public class GetSnapshotsRequest extends ClusterManagerNodeRequest<GetSnapshotsRequest> {
 
     public static final String ALL_SNAPSHOTS = "_all";
     public static final String CURRENT_SNAPSHOT = "_current";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequestBuilder.java
index bd2ced2733169..3434f1cb47a99 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsRequestBuilder.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.get;
 
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
 
 /**
  * Get snapshots request builder
+ *
+ * @opensearch.internal
  */
-public class GetSnapshotsRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class GetSnapshotsRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     GetSnapshotsRequest,
     GetSnapshotsResponse,
     GetSnapshotsRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java
index 28981a6bdafe2..5d5de4c7fa85e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java
@@ -32,16 +32,17 @@
 
 package org.opensearch.action.admin.cluster.snapshots.get;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
@@ -51,6 +52,8 @@
 
 /**
  * Get snapshots response
+ *
+ * @opensearch.internal
  */
 public class GetSnapshotsResponse extends ActionResponse implements ToXContentObject {
 
@@ -125,6 +128,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/TransportGetSnapshotsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/TransportGetSnapshotsAction.java
index 91cec4b268f9b..c7fdc59334874 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/TransportGetSnapshotsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/TransportGetSnapshotsAction.java
@@ -36,10 +36,9 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.util.CollectionUtil;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.StepListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -48,8 +47,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
@@ -76,8 +76,10 @@
 
 /**
  * Transport Action for get snapshots operation
+ *
+ * @opensearch.internal
  */
-public class TransportGetSnapshotsAction extends TransportMasterNodeAction<GetSnapshotsRequest, GetSnapshotsResponse> {
+public class TransportGetSnapshotsAction extends TransportClusterManagerNodeAction<GetSnapshotsRequest, GetSnapshotsResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportGetSnapshotsAction.class);
 
@@ -120,7 +122,7 @@ protected ClusterBlockException checkBlock(GetSnapshotsRequest request, ClusterS
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final GetSnapshotsRequest request,
         final ClusterState state,
         final ActionListener<GetSnapshotsResponse> listener
@@ -136,57 +138,64 @@ protected void masterOperation(
                 currentSnapshots.add(snapshotInfo);
             }
 
-            final RepositoryData repositoryData;
+            final StepListener<RepositoryData> repositoryDataListener = new StepListener<>();
             if (isCurrentSnapshotsOnly(request.snapshots()) == false) {
-                repositoryData = PlainActionFuture.get(fut -> repositoriesService.getRepositoryData(repository, fut));
-                for (SnapshotId snapshotId : repositoryData.getSnapshotIds()) {
-                    allSnapshotIds.put(snapshotId.getName(), snapshotId);
-                }
+                repositoriesService.getRepositoryData(repository, repositoryDataListener);
             } else {
-                repositoryData = null;
+                // Setting repositoryDataListener response to be null if the request has only current snapshot
+                repositoryDataListener.onResponse(null);
             }
+            repositoryDataListener.whenComplete(repositoryData -> {
+                if (repositoryData != null) {
+                    for (SnapshotId snapshotId : repositoryData.getSnapshotIds()) {
+                        allSnapshotIds.put(snapshotId.getName(), snapshotId);
+                    }
+                }
 
-            final Set<SnapshotId> toResolve = new HashSet<>();
-            if (isAllSnapshots(request.snapshots())) {
-                toResolve.addAll(allSnapshotIds.values());
-            } else {
-                for (String snapshotOrPattern : request.snapshots()) {
-                    if (GetSnapshotsRequest.CURRENT_SNAPSHOT.equalsIgnoreCase(snapshotOrPattern)) {
-                        toResolve.addAll(currentSnapshots.stream().map(SnapshotInfo::snapshotId).collect(Collectors.toList()));
-                    } else if (Regex.isSimpleMatchPattern(snapshotOrPattern) == false) {
-                        if (allSnapshotIds.containsKey(snapshotOrPattern)) {
-                            toResolve.add(allSnapshotIds.get(snapshotOrPattern));
-                        } else if (request.ignoreUnavailable() == false) {
-                            throw new SnapshotMissingException(repository, snapshotOrPattern);
-                        }
-                    } else {
-                        for (Map.Entry<String, SnapshotId> entry : allSnapshotIds.entrySet()) {
-                            if (Regex.simpleMatch(snapshotOrPattern, entry.getKey())) {
-                                toResolve.add(entry.getValue());
+                final Set<SnapshotId> toResolve = new HashSet<>();
+                if (isAllSnapshots(request.snapshots())) {
+                    toResolve.addAll(allSnapshotIds.values());
+                } else {
+                    for (String snapshotOrPattern : request.snapshots()) {
+                        if (GetSnapshotsRequest.CURRENT_SNAPSHOT.equalsIgnoreCase(snapshotOrPattern)) {
+                            toResolve.addAll(currentSnapshots.stream().map(SnapshotInfo::snapshotId).collect(Collectors.toList()));
+                        } else if (Regex.isSimpleMatchPattern(snapshotOrPattern) == false) {
+                            if (allSnapshotIds.containsKey(snapshotOrPattern)) {
+                                toResolve.add(allSnapshotIds.get(snapshotOrPattern));
+                            } else if (request.ignoreUnavailable() == false) {
+                                throw new SnapshotMissingException(repository, snapshotOrPattern);
+                            }
+                        } else {
+                            for (Map.Entry<String, SnapshotId> entry : allSnapshotIds.entrySet()) {
+                                if (Regex.simpleMatch(snapshotOrPattern, entry.getKey())) {
+                                    toResolve.add(entry.getValue());
+                                }
                             }
                         }
                     }
-                }
 
-                if (toResolve.isEmpty() && request.ignoreUnavailable() == false && isCurrentSnapshotsOnly(request.snapshots()) == false) {
-                    throw new SnapshotMissingException(repository, request.snapshots()[0]);
+                    if (toResolve.isEmpty()
+                        && request.ignoreUnavailable() == false
+                        && isCurrentSnapshotsOnly(request.snapshots()) == false) {
+                        throw new SnapshotMissingException(repository, request.snapshots()[0]);
+                    }
                 }
-            }
 
-            final List<SnapshotInfo> snapshotInfos;
-            if (request.verbose()) {
-                snapshotInfos = snapshots(snapshotsInProgress, repository, new ArrayList<>(toResolve), request.ignoreUnavailable());
-            } else {
-                if (repositoryData != null) {
-                    // want non-current snapshots as well, which are found in the repository data
-                    snapshotInfos = buildSimpleSnapshotInfos(toResolve, repositoryData, currentSnapshots);
+                final List<SnapshotInfo> snapshotInfos;
+                if (request.verbose()) {
+                    snapshotInfos = snapshots(snapshotsInProgress, repository, new ArrayList<>(toResolve), request.ignoreUnavailable());
                 } else {
-                    // only want current snapshots
-                    snapshotInfos = currentSnapshots.stream().map(SnapshotInfo::basic).collect(Collectors.toList());
-                    CollectionUtil.timSort(snapshotInfos);
+                    if (repositoryData != null) {
+                        // want non-current snapshots as well, which are found in the repository data
+                        snapshotInfos = buildSimpleSnapshotInfos(toResolve, repositoryData, currentSnapshots);
+                    } else {
+                        // only want current snapshots
+                        snapshotInfos = currentSnapshots.stream().map(SnapshotInfo::basic).collect(Collectors.toList());
+                        CollectionUtil.timSort(snapshotInfos);
+                    }
                 }
-            }
-            listener.onResponse(new GetSnapshotsResponse(snapshotInfos));
+                listener.onResponse(new GetSnapshotsResponse(snapshotInfos));
+            }, listener::onFailure);
         } catch (Exception e) {
             listener.onFailure(e);
         }
@@ -237,9 +246,11 @@ private List<SnapshotInfo> snapshots(
             repositoryName,
             snapshotIdsToIterate.stream().map(SnapshotId::getName).collect(Collectors.toList())
         );
+        // filter and incorporate the snapshots in progress
         for (SnapshotsInProgress.Entry entry : entries) {
-            snapshotSet.add(new SnapshotInfo(entry));
-            snapshotIdsToIterate.remove(entry.snapshot().getSnapshotId());
+            if (snapshotIdsToIterate.remove(entry.snapshot().getSnapshotId())) {
+                snapshotSet.add(new SnapshotInfo(entry));
+            }
         }
         // then, look in the repository
         final Repository repository = repositoriesService.repository(repositoryName);
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/package-info.java
new file mode 100644
index 0000000000000..a00088759051c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Snapshot transport handler. */
+package org.opensearch.action.admin.cluster.snapshots.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/package-info.java
new file mode 100644
index 0000000000000..9bfd68dd93178
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Snapshot transport handlers. */
+package org.opensearch.action.admin.cluster.snapshots;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreClusterStateListener.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreClusterStateListener.java
index e596348127faf..1f6e865b78ffd 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreClusterStateListener.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreClusterStateListener.java
@@ -34,34 +34,47 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.RestoreInProgress;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.snapshots.RestoreInfo;
 import org.opensearch.snapshots.RestoreService;
 
+import java.util.Map;
+import java.util.function.Function;
+
 import static org.opensearch.snapshots.RestoreService.restoreInProgress;
 
-public class RestoreClusterStateListener implements ClusterStateListener {
+/**
+ * Transport listener for cluster state updates
+ *
+ * @opensearch.internal
+ */
+public class RestoreClusterStateListener<T extends ActionResponse> implements ClusterStateListener {
 
     private static final Logger logger = LogManager.getLogger(RestoreClusterStateListener.class);
 
     private final ClusterService clusterService;
     private final String uuid;
-    private final ActionListener<RestoreSnapshotResponse> listener;
+    private final String restoreIdentifier;
+    private final ActionListener<T> listener;
+    private final Function<RestoreInfo, T> actionResponseFactory;
 
     private RestoreClusterStateListener(
         ClusterService clusterService,
         RestoreService.RestoreCompletionResponse response,
-        ActionListener<RestoreSnapshotResponse> listener
+        ActionListener<T> listener,
+        Function<RestoreInfo, T> actionResponseFactory
     ) {
         this.clusterService = clusterService;
         this.uuid = response.getUuid();
+        this.restoreIdentifier = response.getSnapshot() != null ? response.getSnapshot().getSnapshotId().getName() : "remote_store";
         this.listener = listener;
+        this.actionResponseFactory = actionResponseFactory;
     }
 
     @Override
@@ -69,27 +82,27 @@ public void clusterChanged(ClusterChangedEvent changedEvent) {
         final RestoreInProgress.Entry prevEntry = restoreInProgress(changedEvent.previousState(), uuid);
         final RestoreInProgress.Entry newEntry = restoreInProgress(changedEvent.state(), uuid);
         if (prevEntry == null) {
-            // When there is a master failure after a restore has been started, this listener might not be registered
-            // on the current master and as such it might miss some intermediary cluster states due to batching.
+            // When there is a cluster-manager failure after a restore has been started, this listener might not be registered
+            // on the current cluster-manager and as such it might miss some intermediary cluster states due to batching.
             // Clean up listener in that case and acknowledge completion of restore operation to client.
             clusterService.removeListener(this);
-            listener.onResponse(new RestoreSnapshotResponse((RestoreInfo) null));
+            listener.onResponse(actionResponseFactory.apply(null));
         } else if (newEntry == null) {
             clusterService.removeListener(this);
-            ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards = prevEntry.shards();
-            assert prevEntry.state().completed() : "expected completed snapshot state but was " + prevEntry.state();
+            final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards = prevEntry.shards();
+            assert prevEntry.state().completed() : "expected completed snapshot/remote store restore state but was " + prevEntry.state();
             assert RestoreService.completed(shards) : "expected all restore entries to be completed";
             RestoreInfo ri = new RestoreInfo(
-                prevEntry.snapshot().getSnapshotId().getName(),
+                restoreIdentifier,
                 prevEntry.indices(),
                 shards.size(),
                 shards.size() - RestoreService.failedShards(shards)
             );
-            RestoreSnapshotResponse response = new RestoreSnapshotResponse(ri);
-            logger.debug("restore of [{}] completed", prevEntry.snapshot().getSnapshotId());
+            T response = actionResponseFactory.apply(ri);
+            logger.debug("restore of [{}] completed", restoreIdentifier);
             listener.onResponse(response);
         } else {
-            // restore not completed yet, wait for next cluster state update
+            logger.debug("restore not completed yet, wait for next cluster state update");
         }
     }
 
@@ -97,11 +110,12 @@ public void clusterChanged(ClusterChangedEvent changedEvent) {
      * Creates a cluster state listener and registers it with the cluster service. The listener passed as a
      * parameter will be called when the restore is complete.
      */
-    public static void createAndRegisterListener(
+    public static <T extends ActionResponse> void createAndRegisterListener(
         ClusterService clusterService,
         RestoreService.RestoreCompletionResponse response,
-        ActionListener<RestoreSnapshotResponse> listener
+        ActionListener<T> listener,
+        Function<RestoreInfo, T> actionResponseFactory
     ) {
-        clusterService.addListener(new RestoreClusterStateListener(clusterService, response, listener));
+        clusterService.addListener(new RestoreClusterStateListener<T>(clusterService, response, listener, actionResponseFactory));
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotAction.java
index e86ad12b8a231..1813e8214aeb0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Restore snapshot action
+ *
+ * @opensearch.internal
  */
 public class RestoreSnapshotAction extends ActionType<RestoreSnapshotResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
index ed45ba4f65941..ff32a68aa9522 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
@@ -33,18 +33,20 @@
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
 import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,18 +56,52 @@
 import java.util.Objects;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
-import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.xcontent.support.XContentMapValues.nodeBooleanValue;
 
 /**
  * Restore snapshot request
+ *
+ * @opensearch.internal
  */
-public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotRequest> implements ToXContentObject {
+public class RestoreSnapshotRequest extends ClusterManagerNodeRequest<RestoreSnapshotRequest> implements ToXContentObject {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(RestoreSnapshotRequest.class);
 
+    /**
+     * Enumeration of possible storage types
+     */
+    public enum StorageType {
+        LOCAL("local"),
+        REMOTE_SNAPSHOT("remote_snapshot");
+
+        private final String text;
+
+        StorageType(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return text;
+        }
+
+        private void toXContent(XContentBuilder builder) throws IOException {
+            builder.field("storage_type", text);
+        }
+
+        private static StorageType fromString(String string) {
+            for (StorageType type : values()) {
+                if (type.text.equals(string)) {
+                    return type;
+                }
+            }
+            throw new IllegalArgumentException("Invalid storage_type: " + string);
+        }
+    }
+
     private String snapshot;
     private String repository;
     private String[] indices = Strings.EMPTY_ARRAY;
@@ -78,6 +114,9 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
     private boolean includeAliases = true;
     private Settings indexSettings = EMPTY_SETTINGS;
     private String[] ignoreIndexSettings = Strings.EMPTY_ARRAY;
+    private StorageType storageType = StorageType.LOCAL;
+    @Nullable
+    private String sourceRemoteStoreRepository = null;
 
     @Nullable // if any snapshot UUID will do
     private String snapshotUuid;
@@ -115,6 +154,12 @@ public RestoreSnapshotRequest(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             snapshotUuid = in.readOptionalString();
         }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            storageType = in.readEnum(StorageType.class);
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            sourceRemoteStoreRepository = in.readOptionalString();
+        }
     }
 
     @Override
@@ -142,6 +187,12 @@ public void writeTo(StreamOutput out) throws IOException {
                 "restricting the snapshot UUID is forbidden in a cluster with version [" + out.getVersion() + "] nodes"
             );
         }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeEnum(storageType);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalString(sourceRemoteStoreRepository);
+        }
     }
 
     @Override
@@ -478,6 +529,41 @@ public String snapshotUuid() {
         return snapshotUuid;
     }
 
+    /**
+     * Sets the storage type for this request.
+     */
+    public RestoreSnapshotRequest storageType(StorageType storageType) {
+        this.storageType = storageType;
+        return this;
+    }
+
+    /**
+     * Gets the storage type for this request. {@link StorageType#LOCAL} is the
+     * implicit default if not overridden.
+     */
+    public StorageType storageType() {
+        return storageType;
+    }
+
+    /**
+     * Sets Source Remote Store Repository for all the restored indices
+     *
+     * @param sourceRemoteStoreRepository name of the remote store repository that should be used for all restored indices.
+     */
+    public RestoreSnapshotRequest setSourceRemoteStoreRepository(String sourceRemoteStoreRepository) {
+        this.sourceRemoteStoreRepository = sourceRemoteStoreRepository;
+        return this;
+    }
+
+    /**
+     * Returns Source Remote Store Repository for all the restored indices
+     *
+     * @return source Remote Store Repository
+     */
+    public String getSourceRemoteStoreRepository() {
+        return sourceRemoteStoreRepository;
+    }
+
     /**
      * Parses restore definition
      *
@@ -535,6 +621,20 @@ public RestoreSnapshotRequest source(Map<String, Object> source) {
                 } else {
                     throw new IllegalArgumentException("malformed ignore_index_settings section, should be an array of strings");
                 }
+            } else if (name.equals("storage_type")) {
+
+                if (entry.getValue() instanceof String) {
+                    storageType(StorageType.fromString((String) entry.getValue()));
+                } else {
+                    throw new IllegalArgumentException("malformed storage_type");
+                }
+
+            } else if (name.equals("source_remote_store_repository")) {
+                if (entry.getValue() instanceof String) {
+                    setSourceRemoteStoreRepository((String) entry.getValue());
+                } else {
+                    throw new IllegalArgumentException("malformed source_remote_store_repository");
+                }
             } else {
                 if (IndicesOptions.isIndicesOptions(name) == false) {
                     throw new IllegalArgumentException("Unknown parameter " + name);
@@ -577,6 +677,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.value(ignoreIndexSetting);
         }
         builder.endArray();
+        if (storageType != null) {
+            storageType.toXContent(builder);
+        }
+        if (sourceRemoteStoreRepository != null) {
+            builder.field("source_remote_store_repository", sourceRemoteStoreRepository);
+        }
         builder.endObject();
         return builder;
     }
@@ -591,7 +697,7 @@ public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         RestoreSnapshotRequest that = (RestoreSnapshotRequest) o;
-        return waitForCompletion == that.waitForCompletion
+        boolean equals = waitForCompletion == that.waitForCompletion
             && includeGlobalState == that.includeGlobalState
             && partial == that.partial
             && includeAliases == that.includeAliases
@@ -603,12 +709,16 @@ public boolean equals(Object o) {
             && Objects.equals(renameReplacement, that.renameReplacement)
             && Objects.equals(indexSettings, that.indexSettings)
             && Arrays.equals(ignoreIndexSettings, that.ignoreIndexSettings)
-            && Objects.equals(snapshotUuid, that.snapshotUuid);
+            && Objects.equals(snapshotUuid, that.snapshotUuid)
+            && Objects.equals(storageType, that.storageType)
+            && Objects.equals(sourceRemoteStoreRepository, that.sourceRemoteStoreRepository);
+        return equals;
     }
 
     @Override
     public int hashCode() {
-        int result = Objects.hash(
+        int result;
+        result = Objects.hash(
             snapshot,
             repository,
             indicesOptions,
@@ -619,7 +729,9 @@ public int hashCode() {
             partial,
             includeAliases,
             indexSettings,
-            snapshotUuid
+            snapshotUuid,
+            storageType,
+            sourceRemoteStoreRepository
         );
         result = 31 * result + Arrays.hashCode(indices);
         result = 31 * result + Arrays.hashCode(ignoreIndexSettings);
@@ -628,6 +740,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
index 19fc86c9c4ace..d9cca536d1c41 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentType;
@@ -43,8 +43,10 @@
 
 /**
  * Restore snapshot request builder
+ *
+ * @opensearch.internal
  */
-public class RestoreSnapshotRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class RestoreSnapshotRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     RestoreSnapshotRequest,
     RestoreSnapshotResponse,
     RestoreSnapshotRequestBuilder> {
@@ -246,4 +248,20 @@ public RestoreSnapshotRequestBuilder setIgnoreIndexSettings(List<String> ignoreI
         request.ignoreIndexSettings(ignoreIndexSettings);
         return this;
     }
+
+    /**
+     * Sets the storage type
+     */
+    public RestoreSnapshotRequestBuilder setStorageType(RestoreSnapshotRequest.StorageType storageType) {
+        request.storageType(storageType);
+        return this;
+    }
+
+    /**
+     * Sets the source remote store repository name
+     */
+    public RestoreSnapshotRequestBuilder setSourceRemoteStoreRepository(String repositoryName) {
+        request.setSourceRemoteStoreRepository(repositoryName);
+        return this;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponse.java
index 324e3054fb1a3..f6e50c69da3dc 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponse.java
@@ -32,26 +32,28 @@
 
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.RestoreInfo;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Contains information about restores snapshot
+ *
+ * @opensearch.internal
  */
 public class RestoreSnapshotResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java
index c07f771081902..73e3070f7e44b 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.RestoreService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -50,8 +50,10 @@
 
 /**
  * Transport action for restore snapshot operation
+ *
+ * @opensearch.internal
  */
-public class TransportRestoreSnapshotAction extends TransportMasterNodeAction<RestoreSnapshotRequest, RestoreSnapshotResponse> {
+public class TransportRestoreSnapshotAction extends TransportClusterManagerNodeAction<RestoreSnapshotRequest, RestoreSnapshotResponse> {
     private final RestoreService restoreService;
 
     @Inject
@@ -100,14 +102,19 @@ protected ClusterBlockException checkBlock(RestoreSnapshotRequest request, Clust
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final RestoreSnapshotRequest request,
         final ClusterState state,
         final ActionListener<RestoreSnapshotResponse> listener
     ) {
         restoreService.restoreSnapshot(request, ActionListener.delegateFailure(listener, (delegatedListener, restoreCompletionResponse) -> {
             if (restoreCompletionResponse.getRestoreInfo() == null && request.waitForCompletion()) {
-                RestoreClusterStateListener.createAndRegisterListener(clusterService, restoreCompletionResponse, delegatedListener);
+                RestoreClusterStateListener.createAndRegisterListener(
+                    clusterService,
+                    restoreCompletionResponse,
+                    delegatedListener,
+                    RestoreSnapshotResponse::new
+                );
             } else {
                 delegatedListener.onResponse(new RestoreSnapshotResponse(restoreCompletionResponse.getRestoreInfo()));
             }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/package-info.java
new file mode 100644
index 0000000000000..69db3f77010ff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/restore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Restore Snapshot transport handler. */
+package org.opensearch.action.admin.cluster.snapshots.restore;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStage.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStage.java
index 59ead89c4a4ee..6e250962d1210 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStage.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStage.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
+/**
+ * Stage for snapshotting an Index Shard
+ *
+ * @opensearch.internal
+ */
 public enum SnapshotIndexShardStage {
 
     /**
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatus.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatus.java
index 74ac12b951dc8..fc3ffd4977da5 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatus.java
@@ -35,24 +35,29 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.action.support.broadcast.BroadcastShardResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Status for snapshotting an Index Shard
+ *
+ * @opensearch.internal
+ */
 public class SnapshotIndexShardStatus extends BroadcastShardResponse implements ToXContentFragment {
 
     private SnapshotIndexShardStage stage = SnapshotIndexShardStage.INIT;
@@ -161,6 +166,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalString(failure);
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String STAGE = "stage";
         static final String REASON = "reason";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatus.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatus.java
index 63cbc0a18ffff..9c2db62c33bd0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatus.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -49,10 +49,12 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Represents snapshot status of all shards in the index
+ *
+ * @opensearch.internal
  */
 public class SnapshotIndexStatus implements Iterable<SnapshotIndexShardStatus>, ToXContentFragment {
 
@@ -122,6 +124,11 @@ public Iterator<SnapshotIndexShardStatus> iterator() {
         return indexShards.values().iterator();
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String SHARDS = "shards";
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStats.java
index b945ba20afe80..ad514a13312ba 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStats.java
@@ -32,20 +32,22 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collection;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Status of a snapshot shards
+ *
+ * @opensearch.internal
  */
 public class SnapshotShardsStats implements ToXContentObject {
 
@@ -139,6 +141,11 @@ public int getTotalShards() {
         return totalShards;
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String SHARDS_STATS = "shards_stats";
         static final String INITIALIZING = "initializing";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStats.java
index 3f348e47c4f4a..babdb7540a314 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStats.java
@@ -32,20 +32,26 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.IOException;
 
+/**
+ * Stats for snapshots
+ *
+ * @opensearch.internal
+ */
 public class SnapshotStats implements Writeable, ToXContentObject {
 
     private long startTime;
@@ -165,6 +171,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeVLong(totalSize);
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String STATS = "stats";
 
@@ -346,7 +357,7 @@ void add(SnapshotStats stats, boolean updateTimestamps) {
             time = endTime - startTime;
         }
         assert time >= 0 : "Update with ["
-            + Strings.toString(stats)
+            + Strings.toString(MediaTypeRegistry.JSON, stats)
             + "]["
             + updateTimestamps
             + "] resulted in negative total time ["
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatus.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatus.java
index 76764a39ff7e2..40d51f17fc914 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatus.java
@@ -36,16 +36,17 @@
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.cluster.SnapshotsInProgress.State;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 
@@ -62,11 +63,13 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Status of a snapshot
+ *
+ * @opensearch.internal
  */
 public class SnapshotStatus implements ToXContentObject, Writeable {
 
@@ -213,7 +216,7 @@ public void writeTo(StreamOutput out) throws IOException {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, false);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, false);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusAction.java
index d4f398d543b81..c4fe06e985f6f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Snapshots status action
+ *
+ * @opensearch.internal
  */
 public class SnapshotsStatusAction extends ActionType<SnapshotsStatusResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequest.java
index f7e29cfef0bb4..22fca3c54c604 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequest.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.admin.cluster.snapshots.status;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -44,8 +44,10 @@
 
 /**
  * Get snapshot status request
+ *
+ * @opensearch.internal
  */
-public class SnapshotsStatusRequest extends MasterNodeRequest<SnapshotsStatusRequest> {
+public class SnapshotsStatusRequest extends ClusterManagerNodeRequest<SnapshotsStatusRequest> {
 
     private String repository = "_all";
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequestBuilder.java
index 67c82182e38c9..55f156d4a470e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusRequestBuilder.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
 
 /**
  * Snapshots status request builder
+ *
+ * @opensearch.internal
  */
-public class SnapshotsStatusRequestBuilder extends MasterNodeOperationRequestBuilder<
+public class SnapshotsStatusRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     SnapshotsStatusRequest,
     SnapshotsStatusResponse,
     SnapshotsStatusRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponse.java
index 8519b1f6a3379..2f0e5e4b4686f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponse.java
@@ -32,24 +32,26 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Snapshot status response
+ *
+ * @opensearch.internal
  */
 public class SnapshotsStatusResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java
index b5247141739b7..26b8be0f5bb82 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java
@@ -44,9 +44,9 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotShardsService;
@@ -63,6 +63,8 @@
 
 /**
  * Transport action that collects snapshot shard statuses from data nodes
+ *
+ * @opensearch.internal
  */
 public class TransportNodesSnapshotsStatus extends TransportNodesAction<
     TransportNodesSnapshotsStatus.Request,
@@ -143,6 +145,11 @@ protected NodeSnapshotStatus nodeOperation(NodeRequest request) {
         }
     }
 
+    /**
+     * Inner Request
+     *
+     * @opensearch.internal
+     */
     public static class Request extends BaseNodesRequest<Request> {
 
         private Snapshot[] snapshots;
@@ -169,6 +176,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Inner Node Snapshot Status
+     *
+     * @opensearch.internal
+     */
     public static class NodesSnapshotStatus extends BaseNodesResponse<NodeSnapshotStatus> {
 
         public NodesSnapshotStatus(StreamInput in) throws IOException {
@@ -190,6 +202,11 @@ protected void writeNodesTo(StreamOutput out, List<NodeSnapshotStatus> nodes) th
         }
     }
 
+    /**
+     * Inner Node Request
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
 
         private final List<Snapshot> snapshots;
@@ -210,6 +227,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Inner Node Shapshot Status
+     *
+     * @opensearch.internal
+     */
     public static class NodeSnapshotStatus extends BaseNodeResponse {
 
         private final Map<Snapshot, Map<ShardId, SnapshotIndexShardStatus>> status;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportSnapshotsStatusAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportSnapshotsStatusAction.java
index 33d4ac5d50347..7f6c039cf2ecc 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportSnapshotsStatusAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/TransportSnapshotsStatusAction.java
@@ -32,15 +32,12 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -48,12 +45,13 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
@@ -84,7 +82,12 @@
 
 import static java.util.Collections.unmodifiableMap;
 
-public class TransportSnapshotsStatusAction extends TransportMasterNodeAction<SnapshotsStatusRequest, SnapshotsStatusResponse> {
+/**
+ * Transport action for accessing snapshot status
+ *
+ * @opensearch.internal
+ */
+public class TransportSnapshotsStatusAction extends TransportClusterManagerNodeAction<SnapshotsStatusRequest, SnapshotsStatusResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportSnapshotsStatusAction.class);
 
@@ -131,7 +134,7 @@ protected SnapshotsStatusResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final SnapshotsStatusRequest request,
         final ClusterState state,
         final ActionListener<SnapshotsStatusResponse> listener
@@ -149,9 +152,9 @@ protected void masterOperation(
 
         Set<String> nodesIds = new HashSet<>();
         for (SnapshotsInProgress.Entry entry : currentSnapshots) {
-            for (ObjectCursor<SnapshotsInProgress.ShardSnapshotStatus> status : entry.shards().values()) {
-                if (status.value.nodeId() != null) {
-                    nodesIds.add(status.value.nodeId());
+            for (final SnapshotsInProgress.ShardSnapshotStatus status : entry.shards().values()) {
+                if (status.nodeId() != null) {
+                    nodesIds.add(status.nodeId());
                 }
             }
         }
@@ -164,7 +167,7 @@ protected void masterOperation(
             }
             transportNodesSnapshotsStatus.execute(
                 new TransportNodesSnapshotsStatus.Request(nodesIds.toArray(Strings.EMPTY_ARRAY)).snapshots(snapshots)
-                    .timeout(request.masterNodeTimeout()),
+                    .timeout(request.clusterManagerNodeTimeout()),
                 ActionListener.wrap(
                     nodeSnapshotStatuses -> threadPool.generic()
                         .execute(
@@ -205,26 +208,26 @@ private void buildResponse(
                 currentSnapshotNames.add(entry.snapshot().getSnapshotId().getName());
                 List<SnapshotIndexShardStatus> shardStatusBuilder = new ArrayList<>();
                 Map<String, IndexId> indexIdLookup = null;
-                for (ObjectObjectCursor<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardEntry : entry.shards()) {
-                    SnapshotsInProgress.ShardSnapshotStatus status = shardEntry.value;
+                for (final Map.Entry<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardEntry : entry.shards().entrySet()) {
+                    SnapshotsInProgress.ShardSnapshotStatus status = shardEntry.getValue();
                     if (status.nodeId() != null) {
                         // We should have information about this shard from the shard:
                         TransportNodesSnapshotsStatus.NodeSnapshotStatus nodeStatus = nodeSnapshotStatusMap.get(status.nodeId());
                         if (nodeStatus != null) {
                             Map<ShardId, SnapshotIndexShardStatus> shardStatues = nodeStatus.status().get(entry.snapshot());
                             if (shardStatues != null) {
-                                SnapshotIndexShardStatus shardStatus = shardStatues.get(shardEntry.key);
+                                SnapshotIndexShardStatus shardStatus = shardStatues.get(shardEntry.getKey());
                                 if (shardStatus != null) {
                                     // We have full information about this shard
                                     if (shardStatus.getStage() == SnapshotIndexShardStage.DONE
-                                        && shardEntry.value.state() != SnapshotsInProgress.ShardState.SUCCESS) {
+                                        && shardEntry.getValue().state() != SnapshotsInProgress.ShardState.SUCCESS) {
                                         // Unlikely edge case:
                                         // Data node has finished snapshotting the shard but the cluster state has not yet been updated
                                         // to reflect this. We adjust the status to show up as snapshot metadata being written because
-                                        // technically if the data node failed before successfully reporting DONE state to master, then
-                                        // this shards state would jump to a failed state.
+                                        // technically if the data node failed before successfully reporting DONE state to cluster-manager,
+                                        // then this shards state would jump to a failed state.
                                         shardStatus = new SnapshotIndexShardStatus(
-                                            shardEntry.key,
+                                            shardEntry.getKey(),
                                             SnapshotIndexShardStage.FINALIZE,
                                             shardStatus.getStats(),
                                             shardStatus.getNodeId(),
@@ -242,7 +245,7 @@ private void buildResponse(
                     // We rebuild the information they would have provided from their in memory state from the cluster
                     // state and the repository contents in the below logic
                     final SnapshotIndexShardStage stage;
-                    switch (shardEntry.value.state()) {
+                    switch (shardEntry.getValue().state()) {
                         case FAILED:
                         case ABORTED:
                         case MISSING:
@@ -257,7 +260,7 @@ private void buildResponse(
                             stage = SnapshotIndexShardStage.DONE;
                             break;
                         default:
-                            throw new IllegalArgumentException("Unknown snapshot state " + shardEntry.value.state());
+                            throw new IllegalArgumentException("Unknown snapshot state " + shardEntry.getValue().state());
                     }
                     final SnapshotIndexShardStatus shardStatus;
                     if (stage == SnapshotIndexShardStage.DONE) {
@@ -266,7 +269,7 @@ private void buildResponse(
                         if (indexIdLookup == null) {
                             indexIdLookup = entry.indices().stream().collect(Collectors.toMap(IndexId::getName, Function.identity()));
                         }
-                        final ShardId shardId = shardEntry.key;
+                        final ShardId shardId = shardEntry.getKey();
                         shardStatus = new SnapshotIndexShardStatus(
                             shardId,
                             repositoriesService.repository(entry.repository())
@@ -278,7 +281,7 @@ private void buildResponse(
                                 .asCopy()
                         );
                     } else {
-                        shardStatus = new SnapshotIndexShardStatus(shardEntry.key, stage);
+                        shardStatus = new SnapshotIndexShardStatus(shardEntry.getKey(), stage);
                     }
                     shardStatusBuilder.add(shardStatus);
                 }
@@ -406,7 +409,7 @@ private SnapshotInfo snapshot(SnapshotsInProgress snapshotsInProgress, String re
     /**
      * Returns status of shards currently finished snapshots
      * <p>
-     * This method is executed on master node and it's complimentary to the
+     * This method is executed on cluster-manager node and it's complimentary to the
      * {@link SnapshotShardsService#currentSnapshotShards(Snapshot)} because it
      * returns similar information but for already finished snapshots.
      * </p>
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/package-info.java
new file mode 100644
index 0000000000000..3244beaf97961
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/snapshots/status/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Snapshot Status transport handlers. */
+package org.opensearch.action.admin.cluster.snapshots.status;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateAction.java
index dff45b708fb13..ba3658d68296e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for obtaining cluster state
+ *
+ * @opensearch.internal
+ */
 public class ClusterStateAction extends ActionType<ClusterStateResponse> {
 
     public static final ClusterStateAction INSTANCE = new ClusterStateAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequest.java
index 91e01aa74f8a5..7c937a1700db0 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequest.java
@@ -35,15 +35,20 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
-public class ClusterStateRequest extends MasterNodeReadRequest<ClusterStateRequest> implements IndicesRequest.Replaceable {
+/**
+ * Transport request for obtaining cluster state
+ *
+ * @opensearch.internal
+ */
+public class ClusterStateRequest extends ClusterManagerNodeReadRequest<ClusterStateRequest> implements IndicesRequest.Replaceable {
 
     public static final TimeValue DEFAULT_WAIT_FOR_NODE_TIMEOUT = TimeValue.timeValueMinutes(1);
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestBuilder.java
index cf3eabfc4167d..b9bfeca9f7386 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestBuilder.java
@@ -33,11 +33,16 @@
 package org.opensearch.action.admin.cluster.state;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
 
-public class ClusterStateRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for obtaining cluster state
+ *
+ * @opensearch.internal
+ */
+public class ClusterStateRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     ClusterStateRequest,
     ClusterStateResponse,
     ClusterStateRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateResponse.java
index d2f053137e446..a6bff09361b33 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/ClusterStateResponse.java
@@ -33,19 +33,21 @@
 package org.opensearch.action.admin.cluster.state;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * The response for getting the cluster state.
+ *
+ * @opensearch.internal
  */
 public class ClusterStateResponse extends ActionResponse {
 
@@ -102,32 +104,37 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeBoolean(waitForTimedOut);
     }
 
+    @Override
+    public String toString() {
+        return "ClusterStateResponse{" + "clusterState=" + clusterState + '}';
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         ClusterStateResponse response = (ClusterStateResponse) o;
         return waitForTimedOut == response.waitForTimedOut && Objects.equals(clusterName, response.clusterName) &&
-        // Best effort. Only compare cluster state version and master node id,
+        // Best effort. Only compare cluster state version and cluster-manager node id,
         // because cluster state doesn't implement equals()
             Objects.equals(getVersion(clusterState), getVersion(response.clusterState))
-            && Objects.equals(getMasterNodeId(clusterState), getMasterNodeId(response.clusterState));
+            && Objects.equals(getClusterManagerNodeId(clusterState), getClusterManagerNodeId(response.clusterState));
     }
 
     @Override
     public int hashCode() {
-        // Best effort. Only use cluster state version and master node id,
+        // Best effort. Only use cluster state version and cluster-manager node id,
         // because cluster state doesn't implement hashcode()
-        return Objects.hash(clusterName, getVersion(clusterState), getMasterNodeId(clusterState), waitForTimedOut);
+        return Objects.hash(clusterName, getVersion(clusterState), getClusterManagerNodeId(clusterState), waitForTimedOut);
     }
 
-    private static String getMasterNodeId(ClusterState clusterState) {
+    private static String getClusterManagerNodeId(ClusterState clusterState) {
         if (clusterState == null) {
             return null;
         }
         DiscoveryNodes nodes = clusterState.getNodes();
         if (nodes != null) {
-            return nodes.getMasterNodeId();
+            return nodes.getClusterManagerNodeId();
         } else {
             return null;
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/TransportClusterStateAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/TransportClusterStateAction.java
index 42497c5244167..4aaa7f1950823 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/state/TransportClusterStateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/TransportClusterStateAction.java
@@ -32,15 +32,13 @@
 
 package org.opensearch.action.admin.cluster.state;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
@@ -49,16 +47,23 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.Map;
 import java.util.function.Predicate;
 
-public class TransportClusterStateAction extends TransportMasterNodeReadAction<ClusterStateRequest, ClusterStateResponse> {
+/**
+ * Transport action for obtaining cluster state
+ *
+ * @opensearch.internal
+ */
+public class TransportClusterStateAction extends TransportClusterManagerNodeReadAction<ClusterStateRequest, ClusterStateResponse> {
 
     private final Logger logger = LogManager.getLogger(getClass());
 
@@ -110,7 +115,7 @@ protected ClusterBlockException checkBlock(ClusterStateRequest request, ClusterS
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ClusterStateRequest request,
         final ClusterState state,
         final ActionListener<ClusterStateResponse> listener
@@ -122,7 +127,7 @@ protected void masterOperation(
 
         final Predicate<ClusterState> acceptableClusterStateOrNotMasterPredicate = request.local()
             ? acceptableClusterStatePredicate
-            : acceptableClusterStatePredicate.or(clusterState -> clusterState.nodes().isLocalNodeElectedMaster() == false);
+            : acceptableClusterStatePredicate.or(clusterState -> clusterState.nodes().isLocalNodeElectedClusterManager() == false);
 
         if (acceptableClusterStatePredicate.test(state)) {
             ActionListener.completeWith(listener, () -> buildResponse(request, state));
@@ -137,8 +142,8 @@ public void onNewClusterState(ClusterState newState) {
                             ActionListener.completeWith(listener, () -> buildResponse(request, newState));
                         } else {
                             listener.onFailure(
-                                new NotMasterException(
-                                    "master stepped down waiting for metadata version " + request.waitForMetadataVersion()
+                                new NotClusterManagerException(
+                                    "cluster-manager stepped down waiting for metadata version " + request.waitForMetadataVersion()
                                 )
                             );
                         }
@@ -207,18 +212,18 @@ private ClusterStateResponse buildResponse(final ClusterStateRequest request, fi
             }
 
             // filter out metadata that shouldn't be returned by the API
-            for (ObjectObjectCursor<String, Custom> custom : currentState.metadata().customs()) {
-                if (custom.value.context().contains(Metadata.XContentContext.API) == false) {
-                    mdBuilder.removeCustom(custom.key);
+            for (final Map.Entry<String, Custom> custom : currentState.metadata().customs().entrySet()) {
+                if (custom.getValue().context().contains(Metadata.XContentContext.API) == false) {
+                    mdBuilder.removeCustom(custom.getKey());
                 }
             }
         }
         builder.metadata(mdBuilder);
 
         if (request.customs()) {
-            for (ObjectObjectCursor<String, ClusterState.Custom> custom : currentState.customs()) {
-                if (custom.value.isPrivate() == false) {
-                    builder.putCustom(custom.key, custom.value);
+            for (final Map.Entry<String, ClusterState.Custom> custom : currentState.customs().entrySet()) {
+                if (custom.getValue().isPrivate() == false) {
+                    builder.putCustom(custom.getKey(), custom.getValue());
                 }
             }
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/state/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/state/package-info.java
new file mode 100644
index 0000000000000..ab935d939e459
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/state/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster State transport handler. */
+package org.opensearch.action.admin.cluster.state;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/AnalysisStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/AnalysisStats.java
index 3ae8d684ee870..3372448bdacae 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/AnalysisStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/AnalysisStats.java
@@ -35,14 +35,15 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -59,6 +60,8 @@
 
 /**
  * Statistics about analysis usage.
+ *
+ * @opensearch.internal
  */
 public final class AnalysisStats implements ToXContentFragment, Writeable {
 
@@ -344,6 +347,6 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsAction.java
index baeeec91bd8ce..ef20087a667df 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for obtaining cluster stats
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsAction extends ActionType<ClusterStatsResponse> {
 
     public static final ClusterStatsAction INSTANCE = new ClusterStatsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIndices.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIndices.java
index dd74c2ad66a9b..63ac76ae65783 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIndices.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIndices.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.action.admin.cluster.stats;
 
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.indices.stats.CommonStats;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.engine.SegmentsStats;
 import org.opensearch.index.fielddata.FieldDataStats;
@@ -45,8 +43,15 @@
 import org.opensearch.search.suggest.completion.CompletionStats;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
+/**
+ * Cluster Stats per index
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsIndices implements ToXContentFragment {
 
     private int indexCount;
@@ -61,7 +66,7 @@ public class ClusterStatsIndices implements ToXContentFragment {
     private MappingStats mappings;
 
     public ClusterStatsIndices(List<ClusterStatsNodeResponse> nodeResponses, MappingStats mappingStats, AnalysisStats analysisStats) {
-        ObjectObjectHashMap<String, ShardStats> countsPerIndex = new ObjectObjectHashMap<>();
+        Map<String, ShardStats> countsPerIndex = new HashMap<>();
 
         this.docs = new DocsStats();
         this.store = new StoreStats();
@@ -96,8 +101,8 @@ public ClusterStatsIndices(List<ClusterStatsNodeResponse> nodeResponses, Mapping
 
         shards = new ShardStats();
         indexCount = countsPerIndex.size();
-        for (ObjectObjectCursor<String, ShardStats> indexCountsCursor : countsPerIndex) {
-            shards.addIndexShardCount(indexCountsCursor.value);
+        for (final ShardStats indexCountsCursor : countsPerIndex.values()) {
+            shards.addIndexShardCount(indexCountsCursor);
         }
 
         this.mappings = mappingStats;
@@ -144,6 +149,11 @@ public AnalysisStats getAnalysis() {
         return analysis;
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String COUNT = "count";
     }
@@ -167,6 +177,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Inner Shard Stats
+     *
+     * @opensearch.internal
+     */
     public static class ShardStats implements ToXContentFragment {
 
         int indices;
@@ -311,6 +326,11 @@ public void addIndexShardCount(ShardStats indexShardCount) {
             }
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String SHARDS = "shards";
             static final String TOTAL = "total";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodeResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodeResponse.java
index 7607a2ef70980..1b25bf84356d6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodeResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodeResponse.java
@@ -39,11 +39,16 @@
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport action for obtaining cluster stats from node level
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsNodeResponse extends BaseNodeResponse {
 
     private final NodeInfo nodeInfo;
@@ -85,7 +90,7 @@ public NodeStats nodeStats() {
     }
 
     /**
-     * Cluster Health Status, only populated on master nodes.
+     * Cluster Health Status, only populated on cluster-manager nodes.
      */
     @Nullable
     public ClusterHealthStatus clusterStatus() {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodes.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodes.java
index fbca94780f827..5689596763cef 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodes.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodes.java
@@ -32,22 +32,21 @@
 
 package org.opensearch.action.admin.cluster.stats;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.cursors.ObjectIntCursor;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.PluginsAndModules;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.Strings;
+import org.opensearch.common.metrics.OperationStats;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.monitor.jvm.JvmInfo;
@@ -69,6 +68,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Per Node Cluster Stats
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsNodes implements ToXContentFragment {
 
     private final Counts counts;
@@ -145,6 +149,11 @@ public Set<PluginInfo> getPlugins() {
         return plugins;
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String COUNT = "count";
         static final String VERSIONS = "versions";
@@ -202,6 +211,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Inner Counts
+     *
+     * @opensearch.internal
+     */
     public static class Counts implements ToXContentFragment {
         static final String COORDINATING_ONLY = "coordinating_only";
 
@@ -246,6 +260,11 @@ public Map<String, Integer> getRoles() {
             return roles;
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String TOTAL = "total";
         }
@@ -260,19 +279,24 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Inner Operating System Stats
+     *
+     * @opensearch.internal
+     */
     public static class OsStats implements ToXContentFragment {
         final int availableProcessors;
         final int allocatedProcessors;
-        final ObjectIntHashMap<String> names;
-        final ObjectIntHashMap<String> prettyNames;
+        final Map<String, Integer> names;
+        final Map<String, Integer> prettyNames;
         final org.opensearch.monitor.os.OsStats.Mem mem;
 
         /**
          * Build the stats from information about each node.
          */
         private OsStats(List<NodeInfo> nodeInfos, List<NodeStats> nodeStatsList) {
-            this.names = new ObjectIntHashMap<>();
-            this.prettyNames = new ObjectIntHashMap<>();
+            final Map<String, Integer> names = new HashMap<>(nodeInfos.size());
+            final Map<String, Integer> prettyNames = new HashMap<>(nodeInfos.size());
             int availableProcessors = 0;
             int allocatedProcessors = 0;
             for (NodeInfo nodeInfo : nodeInfos) {
@@ -280,12 +304,14 @@ private OsStats(List<NodeInfo> nodeInfos, List<NodeStats> nodeStatsList) {
                 allocatedProcessors += nodeInfo.getInfo(OsInfo.class).getAllocatedProcessors();
 
                 if (nodeInfo.getInfo(OsInfo.class).getName() != null) {
-                    names.addTo(nodeInfo.getInfo(OsInfo.class).getName(), 1);
+                    names.merge(nodeInfo.getInfo(OsInfo.class).getName(), 1, Integer::sum);
                 }
                 if (nodeInfo.getInfo(OsInfo.class).getPrettyName() != null) {
-                    prettyNames.addTo(nodeInfo.getInfo(OsInfo.class).getPrettyName(), 1);
+                    prettyNames.merge(nodeInfo.getInfo(OsInfo.class).getPrettyName(), 1, Integer::sum);
                 }
             }
+            this.names = Collections.unmodifiableMap(names);
+            this.prettyNames = Collections.unmodifiableMap(prettyNames);
             this.availableProcessors = availableProcessors;
             this.allocatedProcessors = allocatedProcessors;
 
@@ -318,6 +344,11 @@ public org.opensearch.monitor.os.OsStats.Mem getMem() {
             return mem;
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String AVAILABLE_PROCESSORS = "available_processors";
             static final String ALLOCATED_PROCESSORS = "allocated_processors";
@@ -334,11 +365,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field(Fields.ALLOCATED_PROCESSORS, allocatedProcessors);
             builder.startArray(Fields.NAMES);
             {
-                for (ObjectIntCursor<String> name : names) {
+                for (final Map.Entry<String, Integer> name : names.entrySet()) {
                     builder.startObject();
                     {
-                        builder.field(Fields.NAME, name.key);
-                        builder.field(Fields.COUNT, name.value);
+                        builder.field(Fields.NAME, name.getKey());
+                        builder.field(Fields.COUNT, name.getValue());
                     }
                     builder.endObject();
                 }
@@ -346,11 +377,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.endArray();
             builder.startArray(Fields.PRETTY_NAMES);
             {
-                for (final ObjectIntCursor<String> prettyName : prettyNames) {
+                for (final Map.Entry<String, Integer> prettyName : prettyNames.entrySet()) {
                     builder.startObject();
                     {
-                        builder.field(Fields.PRETTY_NAME, prettyName.key);
-                        builder.field(Fields.COUNT, prettyName.value);
+                        builder.field(Fields.PRETTY_NAME, prettyName.getKey());
+                        builder.field(Fields.COUNT, prettyName.getValue());
                     }
                     builder.endObject();
                 }
@@ -361,6 +392,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Inner Process Stats
+     *
+     * @opensearch.internal
+     */
     public static class ProcessStats implements ToXContentFragment {
 
         final int count;
@@ -431,6 +467,11 @@ public long getMinOpenFileDescriptors() {
             return minOpenFileDescriptors;
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String CPU = "cpu";
             static final String PERCENT = "percent";
@@ -454,9 +495,14 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Inner JVM Stats
+     *
+     * @opensearch.internal
+     */
     public static class JvmStats implements ToXContentFragment {
 
-        private final ObjectIntHashMap<JvmVersion> versions;
+        private final Map<JvmVersion, Integer> versions;
         private final long threads;
         private final long maxUptime;
         private final long heapUsed;
@@ -466,15 +512,15 @@ public static class JvmStats implements ToXContentFragment {
          * Build from lists of information about each node.
          */
         private JvmStats(List<NodeInfo> nodeInfos, List<NodeStats> nodeStatsList) {
-            this.versions = new ObjectIntHashMap<>();
+            final Map<JvmVersion, Integer> versions = new HashMap<>(nodeInfos.size());
             long threads = 0;
             long maxUptime = 0;
             long heapMax = 0;
             long heapUsed = 0;
             for (NodeInfo nodeInfo : nodeInfos) {
-                versions.addTo(new JvmVersion(nodeInfo.getInfo(JvmInfo.class)), 1);
+                versions.merge(new JvmVersion(nodeInfo.getInfo(JvmInfo.class)), 1, Integer::sum);
             }
-
+            this.versions = Collections.unmodifiableMap(versions);
             for (NodeStats nodeStats : nodeStatsList) {
                 org.opensearch.monitor.jvm.JvmStats js = nodeStats.getJvm();
                 if (js == null) {
@@ -495,7 +541,7 @@ private JvmStats(List<NodeInfo> nodeInfos, List<NodeStats> nodeStatsList) {
             this.heapMax = heapMax;
         }
 
-        public ObjectIntHashMap<JvmVersion> getVersions() {
+        public Map<JvmVersion, Integer> getVersions() {
             return versions;
         }
 
@@ -527,6 +573,11 @@ public ByteSizeValue getHeapMax() {
             return new ByteSizeValue(heapMax);
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String VERSIONS = "versions";
             static final String VERSION = "version";
@@ -550,15 +601,15 @@ static final class Fields {
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.humanReadableField(Fields.MAX_UPTIME_IN_MILLIS, Fields.MAX_UPTIME, new TimeValue(maxUptime));
             builder.startArray(Fields.VERSIONS);
-            for (ObjectIntCursor<JvmVersion> v : versions) {
+            for (final Map.Entry<JvmVersion, Integer> v : versions.entrySet()) {
                 builder.startObject();
-                builder.field(Fields.VERSION, v.key.version);
-                builder.field(Fields.VM_NAME, v.key.vmName);
-                builder.field(Fields.VM_VERSION, v.key.vmVersion);
-                builder.field(Fields.VM_VENDOR, v.key.vmVendor);
-                builder.field(Fields.BUNDLED_JDK, v.key.bundledJdk);
-                builder.field(Fields.USING_BUNDLED_JDK, v.key.usingBundledJdk);
-                builder.field(Fields.COUNT, v.value);
+                builder.field(Fields.VERSION, v.getKey().version);
+                builder.field(Fields.VM_NAME, v.getKey().vmName);
+                builder.field(Fields.VM_VERSION, v.getKey().vmVersion);
+                builder.field(Fields.VM_VENDOR, v.getKey().vmVendor);
+                builder.field(Fields.BUNDLED_JDK, v.getKey().bundledJdk);
+                builder.field(Fields.USING_BUNDLED_JDK, v.getKey().usingBundledJdk);
+                builder.field(Fields.COUNT, v.getValue());
                 builder.endObject();
             }
             builder.endArray();
@@ -572,6 +623,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Inner JVM Version
+     *
+     * @opensearch.internal
+     */
     public static class JvmVersion {
         String version;
         String vmName;
@@ -609,6 +665,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * Inner Network Types
+     *
+     * @opensearch.internal
+     */
     static class NetworkTypes implements ToXContentFragment {
 
         private final Map<String, AtomicInteger> transportTypes;
@@ -652,6 +713,11 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
     }
 
+    /**
+     * Inner Discovery Types
+     *
+     * @opensearch.internal
+     */
     static class DiscoveryTypes implements ToXContentFragment {
 
         private final Map<String, AtomicInteger> discoveryTypes;
@@ -677,6 +743,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Inner Packaging Types
+     *
+     * @opensearch.internal
+     */
     static class PackagingTypes implements ToXContentFragment {
 
         private final Map<String, AtomicInteger> packagingTypes;
@@ -709,6 +780,11 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
     }
 
+    /**
+     * Inner Ingest Stats
+     *
+     * @opensearch.internal
+     */
     static class IngestStats implements ToXContentFragment {
 
         final int pipelineCount;
@@ -725,18 +801,18 @@ static class IngestStats implements ToXContentFragment {
                         pipelineIds.add(processorStats.getKey());
                         for (org.opensearch.ingest.IngestStats.ProcessorStat stat : processorStats.getValue()) {
                             stats.compute(stat.getType(), (k, v) -> {
-                                org.opensearch.ingest.IngestStats.Stats nodeIngestStats = stat.getStats();
+                                OperationStats nodeIngestStats = stat.getStats();
                                 if (v == null) {
                                     return new long[] {
-                                        nodeIngestStats.getIngestCount(),
-                                        nodeIngestStats.getIngestFailedCount(),
-                                        nodeIngestStats.getIngestCurrent(),
-                                        nodeIngestStats.getIngestTimeInMillis() };
+                                        nodeIngestStats.getCount(),
+                                        nodeIngestStats.getFailedCount(),
+                                        nodeIngestStats.getCurrent(),
+                                        nodeIngestStats.getTotalTimeInMillis() };
                                 } else {
-                                    v[0] += nodeIngestStats.getIngestCount();
-                                    v[1] += nodeIngestStats.getIngestFailedCount();
-                                    v[2] += nodeIngestStats.getIngestCurrent();
-                                    v[3] += nodeIngestStats.getIngestTimeInMillis();
+                                    v[0] += nodeIngestStats.getCount();
+                                    v[1] += nodeIngestStats.getFailedCount();
+                                    v[2] += nodeIngestStats.getCurrent();
+                                    v[3] += nodeIngestStats.getTotalTimeInMillis();
                                     return v;
                                 }
                             });
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequest.java
index ed658ae23999a..dc472c10f550b 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequest.java
@@ -33,13 +33,15 @@
 package org.opensearch.action.admin.cluster.stats;
 
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * A request to get cluster level stats.
+ *
+ * @opensearch.internal
  */
 public class ClusterStatsRequest extends BaseNodesRequest<ClusterStatsRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequestBuilder.java
index 33c346a493986..aaf5e3aeffeb8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.nodes.NodesOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for obtaining cluster stats
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsRequestBuilder extends NodesOperationRequestBuilder<
     ClusterStatsRequest,
     ClusterStatsResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsResponse.java
index 1470f252756a5..d9751c819d407 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsResponse.java
@@ -38,17 +38,21 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.health.ClusterHealthStatus;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Locale;
 
+/**
+ * Transport response for obtaining cluster stats
+ *
+ * @opensearch.internal
+ */
 public class ClusterStatsResponse extends BaseNodesResponse<ClusterStatsNodeResponse> implements ToXContentFragment {
 
     final ClusterStatsNodes nodesStats;
@@ -60,7 +64,7 @@ public class ClusterStatsResponse extends BaseNodesResponse<ClusterStatsNodeResp
     public ClusterStatsResponse(StreamInput in) throws IOException {
         super(in);
         timestamp = in.readVLong();
-        // it may be that the master switched on us while doing the operation. In this case the status may be null.
+        // it may be that the cluster-manager switched on us while doing the operation. In this case the status may be null.
         status = in.readOptionalWriteable(ClusterHealthStatus::readFrom);
 
         String clusterUUID = null;
@@ -93,7 +97,7 @@ public ClusterStatsResponse(
         indicesStats = new ClusterStatsIndices(nodes, MappingStats.of(state), AnalysisStats.of(state));
         ClusterHealthStatus status = null;
         for (ClusterStatsNodeResponse response : nodes) {
-            // only the master node populates the status
+            // only the cluster-manager node populates the status
             if (response.clusterStatus() != null) {
                 status = response.clusterStatus();
                 break;
@@ -168,7 +172,7 @@ public String toString() {
             builder.startObject();
             toXContent(builder, EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             return "{ \"error\" : \"" + e.getMessage() + "\"}";
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/IndexFeatureStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/IndexFeatureStats.java
index 0c428ee4fe0ee..f833c52493e00 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/IndexFeatureStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/IndexFeatureStats.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.action.admin.cluster.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Statistics about an index feature.
+ *
+ * @opensearch.internal
  */
 public final class IndexFeatureStats implements ToXContent, Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingStats.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingStats.java
index fc4b61af4ddde..64218765a57e6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingStats.java
@@ -35,12 +35,13 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -56,6 +57,8 @@
 
 /**
  * Usage statistics about mappings usage.
+ *
+ * @opensearch.internal
  */
 public final class MappingStats implements ToXContentFragment, Writeable {
 
@@ -128,7 +131,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingVisitor.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingVisitor.java
index 4f16dbcff668e..b2a5acb235ace 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingVisitor.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/MappingVisitor.java
@@ -35,6 +35,11 @@
 import java.util.Map;
 import java.util.function.Consumer;
 
+/**
+ * Visitor pattern for obtaining index mappings
+ *
+ * @opensearch.internal
+ */
 final class MappingVisitor {
 
     private MappingVisitor() {}
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/TransportClusterStatsAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/TransportClusterStatsAction.java
index c0d7519e79862..a189c632a9a22 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/stats/TransportClusterStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/TransportClusterStatsAction.java
@@ -47,8 +47,8 @@
 import org.opensearch.cluster.health.ClusterStateHealth;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.seqno.RetentionLeaseStats;
@@ -64,6 +64,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Transport action for obtaining cluster state
+ *
+ * @opensearch.internal
+ */
 public class TransportClusterStatsAction extends TransportNodesAction<
     ClusterStatsRequest,
     ClusterStatsResponse,
@@ -140,7 +145,7 @@ protected ClusterStatsNodeResponse newNodeResponse(StreamInput in) throws IOExce
 
     @Override
     protected ClusterStatsNodeResponse nodeOperation(ClusterStatsNodeRequest nodeRequest) {
-        NodeInfo nodeInfo = nodeService.info(true, true, false, true, false, true, false, true, false, false, false);
+        NodeInfo nodeInfo = nodeService.info(true, true, false, true, false, true, false, true, false, false, false, false);
         NodeStats nodeStats = nodeService.stats(
             CommonStatsFlags.NONE,
             true,
@@ -157,6 +162,12 @@ protected ClusterStatsNodeResponse nodeOperation(ClusterStatsNodeRequest nodeReq
             false,
             false,
             false,
+            false,
+            false,
+            false,
+            false,
+            false,
+            false,
             false
         );
         List<ShardStats> shardsStats = new ArrayList<>();
@@ -192,7 +203,7 @@ protected ClusterStatsNodeResponse nodeOperation(ClusterStatsNodeRequest nodeReq
         }
 
         ClusterHealthStatus clusterStatus = null;
-        if (clusterService.state().nodes().isLocalNodeElectedMaster()) {
+        if (clusterService.state().nodes().isLocalNodeElectedClusterManager()) {
             clusterStatus = new ClusterStateHealth(clusterService.state()).getStatus();
         }
 
@@ -206,6 +217,11 @@ protected ClusterStatsNodeResponse nodeOperation(ClusterStatsNodeRequest nodeReq
 
     }
 
+    /**
+     * Inner Cluster Stats Node Request
+     *
+     * @opensearch.internal
+     */
     public static class ClusterStatsNodeRequest extends BaseNodeRequest {
 
         ClusterStatsRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/stats/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/stats/package-info.java
new file mode 100644
index 0000000000000..b10c976bbddf6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Stats transport handlers. */
+package org.opensearch.action.admin.cluster.stats;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptAction.java
index ab20c4052938d..3645ef21d2e12 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for deleting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class DeleteStoredScriptAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeleteStoredScriptAction INSTANCE = new DeleteStoredScriptAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequest.java
index eda9aa053854f..7d92162015950 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequest.java
@@ -34,13 +34,18 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport request for deleting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class DeleteStoredScriptRequest extends AcknowledgedRequest<DeleteStoredScriptRequest> {
 
     private String id;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequestBuilder.java
index d45b0b02d9d83..34e0d429f2098 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/DeleteStoredScriptRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for deleting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class DeleteStoredScriptRequestBuilder extends AcknowledgedRequestBuilder<
     DeleteStoredScriptRequest,
     AcknowledgedResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextAction.java
index 9aebd60c8997b..df33aa8081849 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for getting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class GetScriptContextAction extends ActionType<GetScriptContextResponse> {
 
     public static final GetScriptContextAction INSTANCE = new GetScriptContextAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextRequest.java
index 90ec611eeae9d..07d8530eb7ef6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextRequest.java
@@ -33,10 +33,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport context for getting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class GetScriptContextRequest extends ActionRequest {
     public GetScriptContextRequest() {
         super();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponse.java
index 7bfcface8b75c..b91d636b5ec76 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponse.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptContextInfo;
 
 import java.io.IOException;
@@ -54,6 +54,11 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * Transport context response for getting stored scripts
+ *
+ * @opensearch.internal
+ */
 public class GetScriptContextResponse extends ActionResponse implements StatusToXContentObject {
 
     private static final ParseField CONTEXTS = new ParseField("contexts");
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageAction.java
index 90cc05ba983de..b2da146a7ccbe 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for getting script language
+ *
+ * @opensearch.internal
+ */
 public class GetScriptLanguageAction extends ActionType<GetScriptLanguageResponse> {
     public static final GetScriptLanguageAction INSTANCE = new GetScriptLanguageAction();
     public static final String NAME = "cluster:admin/script_language/get";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageRequest.java
index 0a68af3acd5d7..a81ca39595dfb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageRequest.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for getting script language
+ *
+ * @opensearch.internal
+ */
 public class GetScriptLanguageRequest extends ActionRequest {
     public GetScriptLanguageRequest() {
         super();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponse.java
index d9d6fa9e650de..eabac2eb94a02 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponse.java
@@ -32,19 +32,24 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptLanguagesInfo;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport response for getting script language
+ *
+ * @opensearch.internal
+ */
 public class GetScriptLanguageResponse extends ActionResponse implements StatusToXContentObject, Writeable {
     public final ScriptLanguagesInfo info;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptAction.java
index 40d887987ae40..f4cb82d68456a 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for getting stored script
+ *
+ * @opensearch.internal
+ */
 public class GetStoredScriptAction extends ActionType<GetStoredScriptResponse> {
 
     public static final GetStoredScriptAction INSTANCE = new GetStoredScriptAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequest.java
index afecdc09d991d..70384b5fb648e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequest.java
@@ -33,15 +33,20 @@
 package org.opensearch.action.admin.cluster.storedscripts;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
-public class GetStoredScriptRequest extends MasterNodeReadRequest<GetStoredScriptRequest> {
+/**
+ * Transport request for getting stored script
+ *
+ * @opensearch.internal
+ */
+public class GetStoredScriptRequest extends ClusterManagerNodeReadRequest<GetStoredScriptRequest> {
 
     protected String id;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestBuilder.java
index cbae829e76c04..ae969963be62f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestBuilder.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class GetStoredScriptRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for getting stored script
+ *
+ * @opensearch.internal
+ */
+public class GetStoredScriptRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     GetStoredScriptRequest,
     GetStoredScriptResponse,
     GetStoredScriptRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponse.java
index 7739f87db74f9..cf5a3ec44e560 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponse.java
@@ -32,24 +32,29 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.StoredScriptSource;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Transport response for getting stored script
+ *
+ * @opensearch.internal
+ */
 public class GetStoredScriptResponse extends ActionResponse implements StatusToXContentObject {
 
     public static final ParseField _ID_PARSE_FIELD = new ParseField("_id");
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptAction.java
index 75a2dc12d81f6..2845d895a69e8 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for putting stored script
+ *
+ * @opensearch.internal
+ */
 public class PutStoredScriptAction extends ActionType<AcknowledgedResponse> {
 
     public static final PutStoredScriptAction INSTANCE = new PutStoredScriptAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
index 4665354918c8f..f45bee955da02 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
@@ -32,15 +32,18 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.StoredScriptSource;
 
 import java.io.IOException;
@@ -48,19 +51,28 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport request for putting stored script
+ *
+ * @opensearch.internal
+ */
 public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptRequest> implements ToXContentFragment {
 
     private String id;
     private String context;
     private BytesReference content;
-    private XContentType xContentType;
+    private MediaType mediaType;
     private StoredScriptSource source;
 
     public PutStoredScriptRequest(StreamInput in) throws IOException {
         super(in);
         id = in.readOptionalString();
         content = in.readBytesReference();
-        xContentType = in.readEnum(XContentType.class);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
         context = in.readOptionalString();
         source = new StoredScriptSource(in);
     }
@@ -69,12 +81,12 @@ public PutStoredScriptRequest() {
         super();
     }
 
-    public PutStoredScriptRequest(String id, String context, BytesReference content, XContentType xContentType, StoredScriptSource source) {
+    public PutStoredScriptRequest(String id, String context, BytesReference content, MediaType mediaType, StoredScriptSource source) {
         super();
         this.id = id;
         this.context = context;
         this.content = content;
-        this.xContentType = Objects.requireNonNull(xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
         this.source = source;
     }
 
@@ -117,8 +129,8 @@ public BytesReference content() {
         return content;
     }
 
-    public XContentType xContentType() {
-        return xContentType;
+    public MediaType mediaType() {
+        return mediaType;
     }
 
     public StoredScriptSource source() {
@@ -128,10 +140,10 @@ public StoredScriptSource source() {
     /**
      * Set the script source and the content type of the bytes.
      */
-    public PutStoredScriptRequest content(BytesReference content, XContentType xContentType) {
+    public PutStoredScriptRequest content(BytesReference content, MediaType mediaType) {
         this.content = content;
-        this.xContentType = Objects.requireNonNull(xContentType);
-        this.source = StoredScriptSource.parse(content, xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
+        this.source = StoredScriptSource.parse(content, mediaType);
         return this;
     }
 
@@ -140,17 +152,21 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeOptionalString(id);
         out.writeBytesReference(content);
-        out.writeEnum(xContentType);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
         out.writeOptionalString(context);
         source.writeTo(out);
     }
 
     @Override
     public String toString() {
-        String source = "_na_";
+        String source = Strings.UNKNOWN_UUID_VALUE;
 
         try {
-            source = XContentHelper.convertToJson(content, false, xContentType);
+            source = XContentHelper.convertToJson(content, false, mediaType);
         } catch (Exception e) {
             // ignore
         }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
index 414ed3d273b75..2a06cd23c10b6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
@@ -35,9 +35,14 @@
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 
+/**
+ * Transport request builder for putting stored script
+ *
+ * @opensearch.internal
+ */
 public class PutStoredScriptRequestBuilder extends AcknowledgedRequestBuilder<
     PutStoredScriptRequest,
     AcknowledgedResponse,
@@ -55,8 +60,8 @@ public PutStoredScriptRequestBuilder setId(String id) {
     /**
      * Set the source of the script along with the content type of the source
      */
-    public PutStoredScriptRequestBuilder setContent(BytesReference source, XContentType xContentType) {
-        request.content(source, xContentType);
+    public PutStoredScriptRequestBuilder setContent(BytesReference source, MediaType mediaType) {
+        request.content(source, mediaType);
         return this;
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportDeleteStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportDeleteStoredScriptAction.java
index 0b5f9d3040add..b0863939fd04c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportDeleteStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportDeleteStoredScriptAction.java
@@ -32,26 +32,34 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportDeleteStoredScriptAction extends TransportMasterNodeAction<DeleteStoredScriptRequest, AcknowledgedResponse> {
+/**
+ * Transport action for deleting stored script
+ *
+ * @opensearch.internal
+ */
+public class TransportDeleteStoredScriptAction extends TransportClusterManagerNodeAction<DeleteStoredScriptRequest, AcknowledgedResponse> {
 
     private final ScriptService scriptService;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deleteScriptTaskKey;
 
     @Inject
     public TransportDeleteStoredScriptAction(
@@ -72,6 +80,8 @@ public TransportDeleteStoredScriptAction(
             indexNameExpressionResolver
         );
         this.scriptService = scriptService;
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        deleteScriptTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_SCRIPT_KEY, true);
     }
 
     @Override
@@ -85,9 +95,12 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(DeleteStoredScriptRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
-        throws Exception {
-        scriptService.deleteStoredScript(clusterService, request, listener);
+    protected void clusterManagerOperation(
+        DeleteStoredScriptRequest request,
+        ClusterState state,
+        ActionListener<AcknowledgedResponse> listener
+    ) throws Exception {
+        scriptService.deleteStoredScript(clusterService, request, deleteScriptTaskKey, listener);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptContextAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptContextAction.java
index 0bcd9a71109ed..0dd997a47bc7e 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptContextAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptContextAction.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.script.ScriptContextInfo;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
@@ -42,6 +42,11 @@
 
 import java.util.Set;
 
+/**
+ * Transport action for getting script context
+ *
+ * @opensearch.internal
+ */
 public class TransportGetScriptContextAction extends HandledTransportAction<GetScriptContextRequest, GetScriptContextResponse> {
 
     private final ScriptService scriptService;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptLanguageAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptLanguageAction.java
index 255889b63dbd8..f41a22bcd0a4c 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptLanguageAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetScriptLanguageAction.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.script.ScriptService;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Transport action for getting script language
+ *
+ * @opensearch.internal
+ */
 public class TransportGetScriptLanguageAction extends HandledTransportAction<GetScriptLanguageRequest, GetScriptLanguageResponse> {
     private final ScriptService scriptService;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetStoredScriptAction.java
index 4a87f6795da50..db1f1edde2812 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportGetStoredScriptAction.java
@@ -32,23 +32,28 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportGetStoredScriptAction extends TransportMasterNodeReadAction<GetStoredScriptRequest, GetStoredScriptResponse> {
+/**
+ * Transport action for getting stored script
+ *
+ * @opensearch.internal
+ */
+public class TransportGetStoredScriptAction extends TransportClusterManagerNodeReadAction<GetStoredScriptRequest, GetStoredScriptResponse> {
 
     private final ScriptService scriptService;
 
@@ -84,8 +89,11 @@ protected GetStoredScriptResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(GetStoredScriptRequest request, ClusterState state, ActionListener<GetStoredScriptResponse> listener)
-        throws Exception {
+    protected void clusterManagerOperation(
+        GetStoredScriptRequest request,
+        ClusterState state,
+        ActionListener<GetStoredScriptResponse> listener
+    ) throws Exception {
         listener.onResponse(new GetStoredScriptResponse(request.id(), scriptService.getStoredScript(state, request)));
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportPutStoredScriptAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportPutStoredScriptAction.java
index a8288fc0147c2..61ee641b4764d 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportPutStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/TransportPutStoredScriptAction.java
@@ -32,26 +32,34 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportPutStoredScriptAction extends TransportMasterNodeAction<PutStoredScriptRequest, AcknowledgedResponse> {
+/**
+ * Transport action for putting stored script
+ *
+ * @opensearch.internal
+ */
+public class TransportPutStoredScriptAction extends TransportClusterManagerNodeAction<PutStoredScriptRequest, AcknowledgedResponse> {
 
     private final ScriptService scriptService;
+    private final ClusterManagerTaskThrottler.ThrottlingKey putScriptTaskKey;
 
     @Inject
     public TransportPutStoredScriptAction(
@@ -72,6 +80,8 @@ public TransportPutStoredScriptAction(
             indexNameExpressionResolver
         );
         this.scriptService = scriptService;
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        putScriptTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.PUT_SCRIPT_KEY, true);
     }
 
     @Override
@@ -85,9 +95,12 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(PutStoredScriptRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
-        throws Exception {
-        scriptService.putStoredScript(clusterService, request, listener);
+    protected void clusterManagerOperation(
+        PutStoredScriptRequest request,
+        ClusterState state,
+        ActionListener<AcknowledgedResponse> listener
+    ) throws Exception {
+        scriptService.putStoredScript(clusterService, request, putScriptTaskKey, listener);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/package-info.java
new file mode 100644
index 0000000000000..8f2196ded7c23
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Stored Scripts transport handlers. */
+package org.opensearch.action.admin.cluster.storedscripts;
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksAction.java
index 851b88f1e639a..9f3e8720d1f56 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for getting pending cluster tasks
+ *
+ * @opensearch.internal
+ */
 public class PendingClusterTasksAction extends ActionType<PendingClusterTasksResponse> {
 
     public static final PendingClusterTasksAction INSTANCE = new PendingClusterTasksAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequest.java
index 463481fe5d0e5..83e8b93b32e0f 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequest.java
@@ -33,12 +33,17 @@
 package org.opensearch.action.admin.cluster.tasks;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
-public class PendingClusterTasksRequest extends MasterNodeReadRequest<PendingClusterTasksRequest> {
+/**
+ * Transport request for getting pending cluster tasks
+ *
+ * @opensearch.internal
+ */
+public class PendingClusterTasksRequest extends ClusterManagerNodeReadRequest<PendingClusterTasksRequest> {
 
     public PendingClusterTasksRequest() {}
 
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequestBuilder.java
index 8f3bccdf5e55f..b5e77f291a701 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksRequestBuilder.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.action.admin.cluster.tasks;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class PendingClusterTasksRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for getting pending cluster tasks
+ *
+ * @opensearch.internal
+ */
+public class PendingClusterTasksRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     PendingClusterTasksRequest,
     PendingClusterTasksResponse,
     PendingClusterTasksRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksResponse.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksResponse.java
index 5b355f9f00166..118d2cf3065e6 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/PendingClusterTasksResponse.java
@@ -32,17 +32,22 @@
 
 package org.opensearch.action.admin.cluster.tasks;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.service.PendingClusterTask;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Transport response for getting pending cluster tasks
+ *
+ * @opensearch.internal
+ */
 public class PendingClusterTasksResponse extends ActionResponse implements Iterable<PendingClusterTask>, ToXContentObject {
 
     private final List<PendingClusterTask> pendingTasks;
@@ -108,6 +113,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Inner Fields used for creating XContent and parsing
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
 
         static final String TASKS = "tasks";
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/TransportPendingClusterTasksAction.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/TransportPendingClusterTasksAction.java
index 932722eae8a80..5d5053cc80738 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/TransportPendingClusterTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/TransportPendingClusterTasksAction.java
@@ -34,23 +34,28 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.cluster.service.PendingClusterTask;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.List;
 
-public class TransportPendingClusterTasksAction extends TransportMasterNodeReadAction<
+/**
+ * Transport action for getting pending cluster tasks
+ *
+ * @opensearch.internal
+ */
+public class TransportPendingClusterTasksAction extends TransportClusterManagerNodeReadAction<
     PendingClusterTasksRequest,
     PendingClusterTasksResponse> {
 
@@ -95,13 +100,13 @@ protected ClusterBlockException checkBlock(PendingClusterTasksRequest request, C
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         PendingClusterTasksRequest request,
         ClusterState state,
         ActionListener<PendingClusterTasksResponse> listener
     ) {
         logger.trace("fetching pending tasks from cluster service");
-        final List<PendingClusterTask> pendingTasks = clusterService.getMasterService().pendingTasks();
+        final List<PendingClusterTask> pendingTasks = clusterService.getClusterManagerService().pendingTasks();
         logger.trace("done fetching pending tasks from cluster service");
         listener.onResponse(new PendingClusterTasksResponse(pendingTasks));
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/tasks/package-info.java b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/package-info.java
new file mode 100644
index 0000000000000..4169a343aaabf
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/tasks/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Pending Cluster Tasks transport handlers. */
+package org.opensearch.action.admin.cluster.tasks;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/Alias.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/Alias.java
index d8853bcede3ef..fe7b57f779b26 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/Alias.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/Alias.java
@@ -35,18 +35,17 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchGenerationException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 
 import java.io.IOException;
@@ -55,6 +54,8 @@
 
 /**
  * Represents an alias, to be associated with an index
+ *
+ * @opensearch.internal
  */
 public class Alias implements Writeable, ToXContentFragment {
 
@@ -130,9 +131,9 @@ public Alias filter(Map<String, Object> filter) {
             return this;
         }
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             builder.map(filter);
-            this.filter = Strings.toString(builder);
+            this.filter = builder.toString();
             return this;
         } catch (IOException e) {
             throw new OpenSearchGenerationException("Failed to generate [" + filter + "]", e);
@@ -148,10 +149,10 @@ public Alias filter(QueryBuilder filterBuilder) {
             return this;
         }
         try {
-            XContentBuilder builder = XContentFactory.jsonBuilder();
+            XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
             filterBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
             builder.close();
-            this.filter = Strings.toString(builder);
+            this.filter = builder.toString();
             return this;
         } catch (IOException e) {
             throw new OpenSearchGenerationException("Failed to build json for alias request", e);
@@ -283,7 +284,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
         if (filter != null) {
             try (InputStream stream = new BytesArray(filter).streamInput()) {
-                builder.rawField(FILTER.getPreferredName(), stream, XContentType.JSON);
+                builder.rawField(FILTER.getPreferredName(), stream, MediaTypeRegistry.JSON);
             }
         }
 
@@ -310,7 +311,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesAction.java
index 33566820d9762..4d735e984c34e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for listing index aliases
+ *
+ * @opensearch.internal
+ */
 public class IndicesAliasesAction extends ActionType<AcknowledgedResponse> {
 
     public static final IndicesAliasesAction INSTANCE = new IndicesAliasesAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesClusterStateUpdateRequest.java
index f89f8a06727c1..4a445ca92d2dd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesClusterStateUpdateRequest.java
@@ -38,6 +38,8 @@
 
 /**
  * Cluster state update request that allows to add or remove aliases
+ *
+ * @opensearch.internal
  */
 public class IndicesAliasesClusterStateUpdateRequest extends ClusterStateUpdateRequest<IndicesAliasesClusterStateUpdateRequest> {
     private final List<AliasAction> actions;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequest.java
index 9481e6287c878..4a58b7bec7250 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequest.java
@@ -39,22 +39,22 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.cluster.metadata.AliasAction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 
 import java.io.IOException;
@@ -67,11 +67,13 @@
 import java.util.function.Supplier;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
-import static org.opensearch.common.xcontent.ObjectParser.fromList;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ObjectParser.fromList;
 
 /**
  * A request to add/remove aliases for one or more indices.
+ *
+ * @opensearch.internal
  */
 public class IndicesAliasesRequest extends AcknowledgedRequest<IndicesAliasesRequest> implements ToXContentObject {
 
@@ -97,6 +99,8 @@ public IndicesAliasesRequest() {}
 
     /**
      * Request to take one or more actions on one or more indexes and alias combinations.
+     *
+     * @opensearch.internal
      */
     public static class AliasActions implements AliasesRequest, Writeable, ToXContentObject {
 
@@ -116,6 +120,11 @@ public static class AliasActions implements AliasesRequest, Writeable, ToXConten
         private static final ParseField REMOVE = new ParseField("remove");
         private static final ParseField REMOVE_INDEX = new ParseField("remove_index");
 
+        /**
+         * The type of request.
+         *
+         * @opensearch.internal
+         */
         public enum Type {
             ADD((byte) 0, AliasActions.ADD),
             REMOVE((byte) 1, AliasActions.REMOVE),
@@ -440,9 +449,9 @@ public AliasActions filter(Map<String, Object> filter) {
                 return this;
             }
             try {
-                XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+                XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
                 builder.map(filter);
-                this.filter = Strings.toString(builder);
+                this.filter = builder.toString();
                 return this;
             } catch (IOException e) {
                 throw new OpenSearchGenerationException("Failed to generate [" + filter + "]", e);
@@ -458,7 +467,7 @@ public AliasActions filter(QueryBuilder filter) {
                 XContentBuilder builder = XContentFactory.jsonBuilder();
                 filter.toXContent(builder, ToXContent.EMPTY_PARAMS);
                 builder.close();
-                this.filter = Strings.toString(builder);
+                this.filter = builder.toString();
                 return this;
             } catch (IOException e) {
                 throw new OpenSearchGenerationException("Failed to build json for alias request", e);
@@ -544,7 +553,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             }
             if (false == Strings.isEmpty(filter)) {
                 try (InputStream stream = new BytesArray(filter).streamInput()) {
-                    builder.rawField(FILTER.getPreferredName(), stream, XContentType.JSON);
+                    builder.rawField(FILTER.getPreferredName(), stream, MediaTypeRegistry.JSON);
                 }
             }
             if (false == Strings.isEmpty(routing)) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestBuilder.java
index f74363db3dcfd..13c57cc781925 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestBuilder.java
@@ -41,6 +41,8 @@
 
 /**
  * Builder for request to modify many aliases at once.
+ *
+ * @opensearch.internal
  */
 public class IndicesAliasesRequestBuilder extends AcknowledgedRequestBuilder<
     IndicesAliasesRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/TransportIndicesAliasesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/TransportIndicesAliasesAction.java
index 82eb3aed7da16..77cc0662a1c96 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/TransportIndicesAliasesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/TransportIndicesAliasesAction.java
@@ -32,14 +32,12 @@
 
 package org.opensearch.action.admin.indices.alias;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RequestValidators;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -51,10 +49,10 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataIndexAliasesService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.rest.action.admin.indices.AliasesNotFoundException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -64,6 +62,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
@@ -72,8 +71,10 @@
 
 /**
  * Add/remove aliases action
+ *
+ * @opensearch.internal
  */
-public class TransportIndicesAliasesAction extends TransportMasterNodeAction<IndicesAliasesRequest, AcknowledgedResponse> {
+public class TransportIndicesAliasesAction extends TransportClusterManagerNodeAction<IndicesAliasesRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportIndicesAliasesAction.class);
 
@@ -124,7 +125,7 @@ protected ClusterBlockException checkBlock(IndicesAliasesRequest request, Cluste
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final IndicesAliasesRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -198,7 +199,7 @@ protected void masterOperation(
         request.aliasActions().clear();
         IndicesAliasesClusterStateUpdateRequest updateRequest = new IndicesAliasesClusterStateUpdateRequest(unmodifiableList(finalActions))
             .ackTimeout(request.timeout())
-            .masterNodeTimeout(request.masterNodeTimeout());
+            .masterNodeTimeout(request.clusterManagerNodeTimeout());
 
         indexAliasesService.indicesAliases(updateRequest, new ActionListener<ClusterStateUpdateResponse>() {
             @Override
@@ -218,10 +219,10 @@ private static String[] concreteAliases(IndicesAliasesRequest.AliasActions actio
         if (action.expandAliasesWildcards()) {
             // for DELETE we expand the aliases
             String[] indexAsArray = { concreteIndex };
-            ImmutableOpenMap<String, List<AliasMetadata>> aliasMetadata = metadata.findAliases(action, indexAsArray);
+            final Map<String, List<AliasMetadata>> aliasMetadata = metadata.findAliases(action, indexAsArray);
             List<String> finalAliases = new ArrayList<>();
-            for (ObjectCursor<List<AliasMetadata>> curAliases : aliasMetadata.values()) {
-                for (AliasMetadata aliasMeta : curAliases.value) {
+            for (final List<AliasMetadata> curAliases : aliasMetadata.values()) {
+                for (AliasMetadata aliasMeta : curAliases) {
                     finalAliases.add(aliasMeta.alias());
                 }
             }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistAction.java
deleted file mode 100644
index 964648ab04705..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistAction.java
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.alias.exists;
-
-import org.opensearch.action.ActionType;
-
-public class AliasesExistAction extends ActionType<AliasesExistResponse> {
-
-    public static final AliasesExistAction INSTANCE = new AliasesExistAction();
-    public static final String NAME = "indices:admin/aliases/exists";
-
-    private AliasesExistAction() {
-        super(NAME, AliasesExistResponse::new);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistRequestBuilder.java
deleted file mode 100644
index 20949360ddab8..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistRequestBuilder.java
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.alias.exists;
-
-import org.opensearch.action.admin.indices.alias.get.BaseAliasesRequestBuilder;
-import org.opensearch.client.OpenSearchClient;
-
-public class AliasesExistRequestBuilder extends BaseAliasesRequestBuilder<AliasesExistResponse, AliasesExistRequestBuilder> {
-
-    public AliasesExistRequestBuilder(OpenSearchClient client, AliasesExistAction action, String... aliases) {
-        super(client, action, aliases);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistResponse.java
deleted file mode 100644
index 447f10e5ab34a..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/AliasesExistResponse.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.alias.exists;
-
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-
-import java.io.IOException;
-
-public class AliasesExistResponse extends ActionResponse {
-
-    private boolean exists;
-
-    public AliasesExistResponse(boolean exists) {
-        this.exists = exists;
-    }
-
-    AliasesExistResponse(StreamInput in) throws IOException {
-        super(in);
-        exists = in.readBoolean();
-    }
-
-    public boolean exists() {
-        return exists;
-    }
-
-    public boolean isExists() {
-        return exists();
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeBoolean(exists);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/TransportAliasesExistAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/TransportAliasesExistAction.java
deleted file mode 100644
index 8a86a27561527..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/exists/TransportAliasesExistAction.java
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.alias.exists;
-
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
-import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.TransportService;
-
-import java.io.IOException;
-
-public class TransportAliasesExistAction extends TransportMasterNodeReadAction<GetAliasesRequest, AliasesExistResponse> {
-
-    @Inject
-    public TransportAliasesExistAction(
-        TransportService transportService,
-        ClusterService clusterService,
-        ThreadPool threadPool,
-        ActionFilters actionFilters,
-        IndexNameExpressionResolver indexNameExpressionResolver
-    ) {
-        super(
-            AliasesExistAction.NAME,
-            transportService,
-            clusterService,
-            threadPool,
-            actionFilters,
-            GetAliasesRequest::new,
-            indexNameExpressionResolver
-        );
-    }
-
-    @Override
-    protected String executor() {
-        // very lightweight operation, no need to fork
-        return ThreadPool.Names.SAME;
-    }
-
-    @Override
-    protected AliasesExistResponse read(StreamInput in) throws IOException {
-        return new AliasesExistResponse(in);
-    }
-
-    @Override
-    protected ClusterBlockException checkBlock(GetAliasesRequest request, ClusterState state) {
-        return state.blocks()
-            .indicesBlockedException(ClusterBlockLevel.METADATA_READ, indexNameExpressionResolver.concreteIndexNames(state, request));
-    }
-
-    @Override
-    protected void masterOperation(GetAliasesRequest request, ClusterState state, ActionListener<AliasesExistResponse> listener) {
-        String[] concreteIndices = indexNameExpressionResolver.concreteIndexNames(state, request);
-        boolean result = state.metadata().hasAliases(request.aliases(), concreteIndices);
-        listener.onResponse(new AliasesExistResponse(result));
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/BaseAliasesRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/BaseAliasesRequestBuilder.java
index 3d8fa05fb7658..7cda041b7d9cf 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/BaseAliasesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/BaseAliasesRequestBuilder.java
@@ -33,15 +33,20 @@
 package org.opensearch.action.admin.indices.alias.get;
 
 import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.action.ActionResponse;
 
+/**
+ * Base request builder for listing index aliases
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseAliasesRequestBuilder<
     Response extends ActionResponse,
-    Builder extends BaseAliasesRequestBuilder<Response, Builder>> extends MasterNodeReadOperationRequestBuilder<
+    Builder extends BaseAliasesRequestBuilder<Response, Builder>> extends ClusterManagerNodeReadOperationRequestBuilder<
         GetAliasesRequest,
         Response,
         Builder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesAction.java
index 198fa328111b8..d45f988330010 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for listing index aliases
+ *
+ * @opensearch.internal
+ */
 public class GetAliasesAction extends ActionType<GetAliasesResponse> {
 
     public static final GetAliasesAction INSTANCE = new GetAliasesAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequest.java
index 661af82d7020d..28894baa629b3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequest.java
@@ -34,14 +34,19 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.AliasesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
-public class GetAliasesRequest extends MasterNodeReadRequest<GetAliasesRequest> implements AliasesRequest {
+/**
+ * Transport request for listing index aliases
+ *
+ * @opensearch.internal
+ */
+public class GetAliasesRequest extends ClusterManagerNodeReadRequest<GetAliasesRequest> implements AliasesRequest {
 
     private String[] indices = Strings.EMPTY_ARRAY;
     private String[] aliases = Strings.EMPTY_ARRAY;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequestBuilder.java
index f7902ef73fbd5..aecbd689a647c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesRequestBuilder.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for listing index aliases
+ *
+ * @opensearch.internal
+ */
 public class GetAliasesRequestBuilder extends BaseAliasesRequestBuilder<GetAliasesResponse, GetAliasesRequestBuilder> {
 
     public GetAliasesRequestBuilder(OpenSearchClient client, GetAliasesAction action, String... aliases) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponse.java
index 8901a067bb020..e50540e6b9aea 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponse.java
@@ -32,30 +32,36 @@
 
 package org.opensearch.action.admin.indices.alias.get;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Transport response for listing index aliases
+ *
+ * @opensearch.internal
+ */
 public class GetAliasesResponse extends ActionResponse {
 
-    private final ImmutableOpenMap<String, List<AliasMetadata>> aliases;
+    private final Map<String, List<AliasMetadata>> aliases;
 
-    public GetAliasesResponse(ImmutableOpenMap<String, List<AliasMetadata>> aliases) {
-        this.aliases = aliases;
+    public GetAliasesResponse(final Map<String, List<AliasMetadata>> aliases) {
+        this.aliases = Collections.unmodifiableMap(aliases);
     }
 
     public GetAliasesResponse(StreamInput in) throws IOException {
         super(in);
-        aliases = in.readImmutableMap(StreamInput::readString, i -> i.readList(AliasMetadata::new));
+        aliases = in.readMap(StreamInput::readString, i -> i.readList(AliasMetadata::new));
     }
 
-    public ImmutableOpenMap<String, List<AliasMetadata>> getAliases() {
+    public Map<String, List<AliasMetadata>> getAliases() {
         return aliases;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesAction.java
index fa26560e4fedf..3aca9c1976f16 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesAction.java
@@ -31,9 +31,8 @@
 
 package org.opensearch.action.admin.indices.alias.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -41,11 +40,11 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -53,13 +52,20 @@
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-public class TransportGetAliasesAction extends TransportMasterNodeReadAction<GetAliasesRequest, GetAliasesResponse> {
+/**
+ * Transport action for listing index aliases
+ *
+ * @opensearch.internal
+ */
+public class TransportGetAliasesAction extends TransportClusterManagerNodeReadAction<GetAliasesRequest, GetAliasesResponse> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(TransportGetAliasesAction.class);
 
     private final SystemIndices systemIndices;
@@ -107,7 +113,7 @@ protected GetAliasesResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(GetAliasesRequest request, ClusterState state, ActionListener<GetAliasesResponse> listener) {
+    protected void clusterManagerOperation(GetAliasesRequest request, ClusterState state, ActionListener<GetAliasesResponse> listener) {
         String[] concreteIndices;
         // Switch to a context which will drop any deprecation warnings, because there may be indices resolved here which are not
         // returned in the final response. We'll add warnings back later if necessary in checkSystemIndexAccess.
@@ -115,7 +121,7 @@ protected void masterOperation(GetAliasesRequest request, ClusterState state, Ac
             concreteIndices = indexNameExpressionResolver.concreteIndexNames(state, request);
         }
         final boolean systemIndexAccessAllowed = indexNameExpressionResolver.isSystemIndexAccessAllowed();
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = state.metadata().findAliases(request, concreteIndices);
+        final Map<String, List<AliasMetadata>> aliases = state.metadata().findAliases(request, concreteIndices);
         listener.onResponse(
             new GetAliasesResponse(postProcess(request, concreteIndices, aliases, state, systemIndexAccessAllowed, systemIndices))
         );
@@ -124,23 +130,23 @@ protected void masterOperation(GetAliasesRequest request, ClusterState state, Ac
     /**
      * Fills alias result with empty entries for requested indices when no specific aliases were requested.
      */
-    static ImmutableOpenMap<String, List<AliasMetadata>> postProcess(
+    static Map<String, List<AliasMetadata>> postProcess(
         GetAliasesRequest request,
         String[] concreteIndices,
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases,
+        final Map<String, List<AliasMetadata>> aliases,
         ClusterState state,
         boolean systemIndexAccessAllowed,
         SystemIndices systemIndices
     ) {
         boolean noAliasesSpecified = request.getOriginalAliases() == null || request.getOriginalAliases().length == 0;
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> mapBuilder = ImmutableOpenMap.builder(aliases);
+        final Map<String, List<AliasMetadata>> mapBuilder = new HashMap<>(aliases);
         for (String index : concreteIndices) {
             if (aliases.get(index) == null && noAliasesSpecified) {
                 List<AliasMetadata> previous = mapBuilder.put(index, Collections.emptyList());
                 assert previous == null;
             }
         }
-        final ImmutableOpenMap<String, List<AliasMetadata>> finalResponse = mapBuilder.build();
+        final Map<String, List<AliasMetadata>> finalResponse = Collections.unmodifiableMap(mapBuilder);
         if (systemIndexAccessAllowed == false) {
             checkSystemIndexAccess(request, systemIndices, state, finalResponse);
         }
@@ -151,10 +157,10 @@ private static void checkSystemIndexAccess(
         GetAliasesRequest request,
         SystemIndices systemIndices,
         ClusterState state,
-        ImmutableOpenMap<String, List<AliasMetadata>> aliasesMap
+        final Map<String, List<AliasMetadata>> aliasesMap
     ) {
         Set<String> systemIndicesNames = new HashSet<>();
-        for (Iterator<String> it = aliasesMap.keysIt(); it.hasNext();) {
+        for (Iterator<String> it = aliasesMap.keySet().iterator(); it.hasNext();) {
             String indexName = it.next();
             IndexMetadata index = state.metadata().index(indexName);
             if (index != null && index.isSystem()) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/package-info.java
new file mode 100644
index 0000000000000..e4ea33da95743
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Alias transport handler. */
+package org.opensearch.action.admin.indices.alias.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/alias/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/alias/package-info.java
new file mode 100644
index 0000000000000..3630775073c68
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/alias/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Alias transport handlers. */
+package org.opensearch.action.admin.indices.alias;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeAction.java
index 592575d9b6019..6514e84b4c2bd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeAction.java
@@ -34,19 +34,20 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.NameOrDefinition;
 
 import java.io.IOException;
@@ -59,6 +60,11 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport action for analyzing text
+ *
+ * @opensearch.internal
+ */
 public class AnalyzeAction extends ActionType<AnalyzeAction.Response> {
 
     public static final AnalyzeAction INSTANCE = new AnalyzeAction();
@@ -71,6 +77,8 @@ private AnalyzeAction() {
     /**
      * A request to analyze a text associated with a specific index. Allow to provide
      * the actual analyzer name to perform the analysis with.
+     *
+     * @opensearch.internal
      */
     public static class Request extends SingleShardRequest<Request> {
 
@@ -298,6 +306,11 @@ public static Request fromXContent(XContentParser parser, String index) throws I
 
     }
 
+    /**
+     * Inner Response
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse implements ToXContentObject {
 
         private final DetailAnalyzeResponse detail;
@@ -397,9 +410,14 @@ public int hashCode() {
 
         @Override
         public String toString() {
-            return Strings.toString(this, true, true);
+            return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
         }
 
+        /**
+         * Inner Fields used for creating XContent and parsing
+         *
+         * @opensearch.internal
+         */
         static final class Fields {
             static final String TOKENS = "tokens";
 
@@ -407,6 +425,11 @@ static final class Fields {
         }
     }
 
+    /**
+     * Inner Analyze Token
+     *
+     * @opensearch.internal
+     */
     public static class AnalyzeToken implements Writeable, ToXContentObject {
         private final String term;
         private final int startOffset;
@@ -540,6 +563,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Inner Detail Analyze Response
+     *
+     * @opensearch.internal
+     */
     public static class DetailAnalyzeResponse implements Writeable, ToXContentFragment {
 
         private final boolean customAnalyzer;
@@ -702,6 +730,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Inner Analyze Token List
+     *
+     * @opensearch.internal
+     */
     public static class AnalyzeTokenList implements Writeable, ToXContentObject {
         private final String name;
         private final AnalyzeToken[] tokens;
@@ -794,6 +827,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Inner character filtered text
+     *
+     * @opensearch.internal
+     */
     public static class CharFilteredText implements Writeable, ToXContentObject {
         private final String name;
         private final String[] texts;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestBuilder.java
index 167feb7935be2..a7f21b2af16fc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestBuilder.java
@@ -36,6 +36,11 @@
 
 import java.util.Map;
 
+/**
+ * Transport request builder for analyzing text
+ *
+ * @opensearch.internal
+ */
 public class AnalyzeRequestBuilder extends SingleShardOperationRequestBuilder<
     AnalyzeAction.Request,
     AnalyzeAction.Response,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/analyze/TransportAnalyzeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/analyze/TransportAnalyzeAction.java
index cf578af8dbacb..8dc55e580b9ec 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/analyze/TransportAnalyzeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/analyze/TransportAnalyzeAction.java
@@ -49,9 +49,10 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalysisRegistry;
@@ -64,7 +65,6 @@
 import org.opensearch.index.analysis.TokenizerFactory;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.StringFieldType;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -82,6 +82,8 @@
 
 /**
  * Transport action used to execute analyze requests
+ *
+ * @opensearch.internal
  */
 public class TransportAnalyzeAction extends TransportSingleShardAction<AnalyzeAction.Request, AnalyzeAction.Response> {
 
@@ -465,6 +467,11 @@ private static String writeCharStream(Reader input) {
         return sb.toString();
     }
 
+    /**
+     * Inner Token Counter
+     *
+     * @opensearch.internal
+     */
     private static class TokenCounter {
         private int tokenCount = 0;
         private int maxTokenCount;
@@ -486,6 +493,11 @@ private void increment() {
         }
     }
 
+    /**
+     * Inner Token List Creator
+     *
+     * @opensearch.internal
+     */
     private static class TokenListCreator {
         int lastPosition = -1;
         int lastOffset = 0;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/analyze/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/analyze/package-info.java
new file mode 100644
index 0000000000000..2de987da0f204
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/analyze/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Indices analyze transport handler. */
+package org.opensearch.action.admin.indices.analyze;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheAction.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheAction.java
index b21b52f063691..f605f042a05ac 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for clearing cache
+ *
+ * @opensearch.internal
+ */
 public class ClearIndicesCacheAction extends ActionType<ClearIndicesCacheResponse> {
 
     public static final ClearIndicesCacheAction INSTANCE = new ClearIndicesCacheAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequest.java
index a9eafc7defaba..3b69a0980e97f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequest.java
@@ -32,18 +32,25 @@
 
 package org.opensearch.action.admin.indices.cache.clear;
 
+import org.opensearch.Version;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for clearing cache
+ *
+ * @opensearch.internal
+ */
 public class ClearIndicesCacheRequest extends BroadcastRequest<ClearIndicesCacheRequest> {
 
     private boolean queryCache = false;
     private boolean fieldDataCache = false;
     private boolean requestCache = false;
+    private boolean fileCache = false;
     private String[] fields = Strings.EMPTY_ARRAY;
 
     public ClearIndicesCacheRequest(StreamInput in) throws IOException {
@@ -52,6 +59,9 @@ public ClearIndicesCacheRequest(StreamInput in) throws IOException {
         fieldDataCache = in.readBoolean();
         fields = in.readStringArray();
         requestCache = in.readBoolean();
+        if (in.getVersion().onOrAfter(Version.V_2_8_0)) {
+            fileCache = in.readBoolean();
+        }
     }
 
     public ClearIndicesCacheRequest(String... indices) {
@@ -85,6 +95,15 @@ public ClearIndicesCacheRequest fieldDataCache(boolean fieldDataCache) {
         return this;
     }
 
+    public boolean fileCache() {
+        return this.fileCache;
+    }
+
+    public ClearIndicesCacheRequest fileCache(boolean fileCache) {
+        this.fileCache = fileCache;
+        return this;
+    }
+
     public ClearIndicesCacheRequest fields(String... fields) {
         this.fields = fields == null ? Strings.EMPTY_ARRAY : fields;
         return this;
@@ -101,5 +120,8 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeBoolean(fieldDataCache);
         out.writeStringArrayNullable(fields);
         out.writeBoolean(requestCache);
+        if (out.getVersion().onOrAfter(Version.V_2_8_0)) {
+            out.writeBoolean(fileCache);
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequestBuilder.java
index c7365a0e22e83..e0513e77a5aa5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for clearing cache
+ *
+ * @opensearch.internal
+ */
 public class ClearIndicesCacheRequestBuilder extends BroadcastOperationRequestBuilder<
     ClearIndicesCacheRequest,
     ClearIndicesCacheResponse,
@@ -54,6 +59,11 @@ public ClearIndicesCacheRequestBuilder setRequestCache(boolean requestCache) {
         return this;
     }
 
+    public ClearIndicesCacheRequestBuilder setFileCache(boolean fileCache) {
+        request.fileCache(fileCache);
+        return this;
+    }
+
     public ClearIndicesCacheRequestBuilder setFieldDataCache(boolean fieldDataCache) {
         request.fieldDataCache(fieldDataCache);
         return this;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponse.java
index 58d8767697528..0c6c5ca27b24d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponse.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.indices.cache.clear;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -44,6 +44,8 @@
 
 /**
  * The response of a clear cache action.
+ *
+ * @opensearch.internal
  */
 public class ClearIndicesCacheResponse extends BroadcastResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheAction.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheAction.java
index baa51e023e75a..acc6a6c14c5fd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.admin.indices.cache.clear;
 
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -43,16 +42,23 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.shard.ShardPath;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.node.Node;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.List;
+import java.util.function.Predicate;
 
 /**
  * Indices clear cache action.
+ *
+ * @opensearch.internal
  */
 public class TransportClearIndicesCacheAction extends TransportBroadcastByNodeAction<
     ClearIndicesCacheRequest,
@@ -61,11 +67,14 @@ public class TransportClearIndicesCacheAction extends TransportBroadcastByNodeAc
 
     private final IndicesService indicesService;
 
+    private final Node node;
+
     @Inject
     public TransportClearIndicesCacheAction(
         ClusterService clusterService,
         TransportService transportService,
         IndicesService indicesService,
+        Node node,
         ActionFilters actionFilters,
         IndexNameExpressionResolver indexNameExpressionResolver
     ) {
@@ -80,6 +89,7 @@ public TransportClearIndicesCacheAction(
             false
         );
         this.indicesService = indicesService;
+        this.node = node;
     }
 
     @Override
@@ -107,6 +117,14 @@ protected ClearIndicesCacheRequest readRequestFrom(StreamInput in) throws IOExce
 
     @Override
     protected EmptyResult shardOperation(ClearIndicesCacheRequest request, ShardRouting shardRouting) {
+        if (request.fileCache()) {
+            if (node.fileCache() != null) {
+                ShardPath shardPath = ShardPath.loadFileCachePath(node.getNodeEnvironment(), shardRouting.shardId());
+                Predicate<Path> pathStartsWithShardPathPredicate = path -> path.startsWith(shardPath.getDataPath());
+                node.fileCache().prune(pathStartsWithShardPathPredicate);
+            }
+        }
+
         indicesService.clearIndexShardCache(
             shardRouting.shardId(),
             request.queryCache(),
@@ -127,11 +145,11 @@ protected ShardsIterator shards(ClusterState clusterState, ClearIndicesCacheRequ
 
     @Override
     protected ClusterBlockException checkGlobalBlock(ClusterState state, ClearIndicesCacheRequest request) {
-        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
     }
 
     @Override
     protected ClusterBlockException checkRequestBlock(ClusterState state, ClearIndicesCacheRequest request, String[] concreteIndices) {
-        return state.blocks().indicesBlockedException(ClusterBlockLevel.METADATA_WRITE, concreteIndices);
+        return state.blocks().indicesBlockedException(ClusterBlockLevel.METADATA_READ, concreteIndices);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/package-info.java
new file mode 100644
index 0000000000000..41e8437bc15c1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/clear/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Clear indices cache transport handler. */
+package org.opensearch.action.admin.indices.cache.clear;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/cache/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/cache/package-info.java
new file mode 100644
index 0000000000000..367c663bdc637
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/cache/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Indices Cache transport handlers. */
+package org.opensearch.action.admin.indices.cache;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexAction.java
index ae8347a5ce812..2dea3e415ae0d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for closing an index
+ *
+ * @opensearch.internal
+ */
 public class CloseIndexAction extends ActionType<CloseIndexResponse> {
 
     public static final CloseIndexAction INSTANCE = new CloseIndexAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexClusterStateUpdateRequest.java
index b94d080a331be..4b446f9d1ad2a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexClusterStateUpdateRequest.java
@@ -36,6 +36,8 @@
 
 /**
  * Cluster state update request that allows to close one or more indices
+ *
+ * @opensearch.internal
  */
 public class CloseIndexClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<CloseIndexClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequest.java
index 3fa1c8f066135..2c3d350824904 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequest.java
@@ -38,9 +38,9 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
 
@@ -48,6 +48,8 @@
 
 /**
  * A request to close an index.
+ *
+ * @opensearch.internal
  */
 public class CloseIndexRequest extends AcknowledgedRequest<CloseIndexRequest> implements IndicesRequest.Replaceable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequestBuilder.java
index 66dc07e35fbaa..b3b53a0043c70 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexRequestBuilder.java
@@ -39,6 +39,8 @@
 
 /**
  * Builder for close index request
+ *
+ * @opensearch.internal
  */
 public class CloseIndexRequestBuilder extends AcknowledgedRequestBuilder<CloseIndexRequest, CloseIndexResponse, CloseIndexRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexResponse.java
index 998ffc4af7028..ab05399cf7c35 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/CloseIndexResponse.java
@@ -33,17 +33,18 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -52,6 +53,11 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableList;
 
+/**
+ * Transport response for closing an index
+ *
+ * @opensearch.internal
+ */
 public class CloseIndexResponse extends ShardsAcknowledgedResponse {
 
     private final List<IndexResult> indices;
@@ -97,9 +103,14 @@ protected void addCustomFields(final XContentBuilder builder, final Params param
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * Inner index result
+     *
+     * @opensearch.internal
+     */
     public static class IndexResult implements Writeable, ToXContentFragment {
 
         private final Index index;
@@ -191,10 +202,15 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
     }
 
+    /**
+     * Shard Result from Close Index Response
+     *
+     * @opensearch.internal
+     */
     public static class ShardResult implements Writeable, ToXContentFragment {
 
         private final int id;
@@ -245,9 +261,14 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
+        /**
+         * Inner Failure if something goes wrong
+         *
+         * @opensearch.internal
+         */
         public static class Failure extends DefaultShardOperationFailedException {
 
             private @Nullable String nodeId;
@@ -286,7 +307,7 @@ public XContentBuilder innerToXContent(final XContentBuilder builder, final Para
 
             @Override
             public String toString() {
-                return Strings.toString(this);
+                return Strings.toString(MediaTypeRegistry.JSON, this);
             }
 
             static Failure readFailure(final StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/TransportCloseIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/close/TransportCloseIndexAction.java
index 13525a2a3b23e..cde2ef63df02d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/TransportCloseIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/TransportCloseIndexAction.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.DestructiveOperations;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -46,12 +45,13 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -61,8 +61,10 @@
 
 /**
  * Close index action
+ *
+ * @opensearch.internal
  */
-public class TransportCloseIndexAction extends TransportMasterNodeAction<CloseIndexRequest, CloseIndexResponse> {
+public class TransportCloseIndexAction extends TransportClusterManagerNodeAction<CloseIndexRequest, CloseIndexResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportCloseIndexAction.class);
 
@@ -138,7 +140,7 @@ protected ClusterBlockException checkBlock(CloseIndexRequest request, ClusterSta
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final CloseIndexRequest request,
         final ClusterState state,
         final ActionListener<CloseIndexResponse> listener
@@ -147,7 +149,7 @@ protected void masterOperation(
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final Task task,
         final CloseIndexRequest request,
         final ClusterState state,
@@ -161,7 +163,10 @@ protected void masterOperation(
 
         final CloseIndexClusterStateUpdateRequest closeRequest = new CloseIndexClusterStateUpdateRequest(task.getId()).ackTimeout(
             request.timeout()
-        ).masterNodeTimeout(request.masterNodeTimeout()).waitForActiveShards(request.waitForActiveShards()).indices(concreteIndices);
+        )
+            .masterNodeTimeout(request.clusterManagerNodeTimeout())
+            .waitForActiveShards(request.waitForActiveShards())
+            .indices(concreteIndices);
         indexStateService.closeIndices(closeRequest, ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
             logger.debug(() -> new ParameterizedMessage("failed to close indices [{}]", (Object) concreteIndices), t);
             delegatedListener.onFailure(t);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseAction.java b/server/src/main/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseAction.java
index 8baf1f5d851ad..c869c4c055598 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseAction.java
@@ -34,7 +34,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ReplicationOperation;
@@ -46,20 +45,26 @@
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport action for verifying a shard before closing an index
+ *
+ * @opensearch.internal
+ */
 public class TransportVerifyShardBeforeCloseAction extends TransportReplicationAction<
     TransportVerifyShardBeforeCloseAction.ShardRequest,
     TransportVerifyShardBeforeCloseAction.ShardRequest,
@@ -186,6 +191,11 @@ public void markShardCopyAsStaleIfNeeded(
         }
     }
 
+    /**
+     * Shard Request for verifying shards before closing
+     *
+     * @opensearch.internal
+     */
     public static class ShardRequest extends ReplicationRequest<ShardRequest> {
 
         private final ClusterBlock clusterBlock;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/close/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/close/package-info.java
new file mode 100644
index 0000000000000..fb2d419124461
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/close/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Close indices transport handlers. */
+package org.opensearch.action.admin.indices.close;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/AutoCreateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/create/AutoCreateAction.java
index 23cb728540ab3..02dd2de803f58 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/AutoCreateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/AutoCreateAction.java
@@ -31,29 +31,31 @@
 
 package org.opensearch.action.admin.indices.create;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.ActiveShardsObserver;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate.DataStreamTemplate;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataCreateDataStreamService;
 import org.opensearch.cluster.metadata.MetadataCreateDataStreamService.CreateDataStreamClusterStateUpdateRequest;
 import org.opensearch.cluster.metadata.MetadataCreateIndexService;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -62,6 +64,8 @@
 
 /**
  * Api that auto creates an index or data stream that originate from requests that write into an index that doesn't yet exist.
+ *
+ * @opensearch.internal
  */
 public final class AutoCreateAction extends ActionType<CreateIndexResponse> {
 
@@ -72,11 +76,17 @@ private AutoCreateAction() {
         super(NAME, CreateIndexResponse::new);
     }
 
-    public static final class TransportAction extends TransportMasterNodeAction<CreateIndexRequest, CreateIndexResponse> {
+    /**
+     * Transport Action for Auto Create
+     *
+     * @opensearch.internal
+     */
+    public static final class TransportAction extends TransportClusterManagerNodeAction<CreateIndexRequest, CreateIndexResponse> {
 
         private final ActiveShardsObserver activeShardsObserver;
         private final MetadataCreateIndexService createIndexService;
         private final MetadataCreateDataStreamService metadataCreateDataStreamService;
+        private final ClusterManagerTaskThrottler.ThrottlingKey autoCreateTaskKey;
 
         @Inject
         public TransportAction(
@@ -92,6 +102,9 @@ public TransportAction(
             this.activeShardsObserver = new ActiveShardsObserver(clusterService, threadPool);
             this.createIndexService = createIndexService;
             this.metadataCreateDataStreamService = metadataCreateDataStreamService;
+
+            // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+            autoCreateTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.AUTO_CREATE_KEY, true);
         }
 
         @Override
@@ -105,7 +118,11 @@ protected CreateIndexResponse read(StreamInput in) throws IOException {
         }
 
         @Override
-        protected void masterOperation(CreateIndexRequest request, ClusterState state, ActionListener<CreateIndexResponse> finalListener) {
+        protected void clusterManagerOperation(
+            CreateIndexRequest request,
+            ClusterState state,
+            ActionListener<CreateIndexResponse> finalListener
+        ) {
             AtomicReference<String> indexNameRef = new AtomicReference<>();
             ActionListener<ClusterStateUpdateResponse> listener = ActionListener.wrap(response -> {
                 String indexName = indexNameRef.get();
@@ -115,7 +132,9 @@ protected void masterOperation(CreateIndexRequest request, ClusterState state, A
                         new String[] { indexName },
                         ActiveShardCount.DEFAULT,
                         request.timeout(),
-                        shardsAcked -> { finalListener.onResponse(new CreateIndexResponse(true, shardsAcked, indexName)); },
+                        shardsAcked -> {
+                            finalListener.onResponse(new CreateIndexResponse(true, shardsAcked, indexName));
+                        },
                         finalListener::onFailure
                     );
                 } else {
@@ -131,13 +150,18 @@ protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                         return new ClusterStateUpdateResponse(acknowledged);
                     }
 
+                    @Override
+                    public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                        return autoCreateTaskKey;
+                    }
+
                     @Override
                     public ClusterState execute(ClusterState currentState) throws Exception {
                         DataStreamTemplate dataStreamTemplate = resolveAutoCreateDataStream(request, currentState.metadata());
                         if (dataStreamTemplate != null) {
                             CreateDataStreamClusterStateUpdateRequest createRequest = new CreateDataStreamClusterStateUpdateRequest(
                                 request.index(),
-                                request.masterNodeTimeout(),
+                                request.clusterManagerNodeTimeout(),
                                 request.timeout()
                             );
                             ClusterState clusterState = metadataCreateDataStreamService.createDataStream(createRequest, currentState);
@@ -150,7 +174,7 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                                 request.cause(),
                                 indexName,
                                 request.index()
-                            ).ackTimeout(request.timeout()).masterNodeTimeout(request.masterNodeTimeout());
+                            ).ackTimeout(request.timeout()).masterNodeTimeout(request.clusterManagerNodeTimeout());
                             return createIndexService.applyCreateIndexRequest(currentState, updateRequest, false);
                         }
                     }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexAction.java
index 87bbc093fce43..220620790fa4d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for creating an index
+ *
+ * @opensearch.internal
+ */
 public class CreateIndexAction extends ActionType<CreateIndexResponse> {
 
     public static final CreateIndexAction INSTANCE = new CreateIndexAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexClusterStateUpdateRequest.java
index 5ca6fb4226b64..ad45e5346f9fa 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexClusterStateUpdateRequest.java
@@ -39,13 +39,15 @@
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.HashSet;
 import java.util.Set;
 
 /**
  * Cluster state update request that allows to create an index
+ *
+ * @opensearch.internal
  */
 public class CreateIndexClusterStateUpdateRequest extends ClusterStateUpdateRequest<CreateIndexClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequest.java
index 7f1f516d13a04..72b65138f59c9 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequest.java
@@ -43,21 +43,21 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -80,6 +80,8 @@
  * @see org.opensearch.client.IndicesAdminClient#create(CreateIndexRequest)
  * @see org.opensearch.client.Requests#createIndexRequest(String)
  * @see CreateIndexResponse
+ *
+ * @opensearch.internal
  */
 public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest> implements IndicesRequest {
 
@@ -210,17 +212,28 @@ public CreateIndexRequest settings(Settings settings) {
 
     /**
      * The settings to create the index with (either json or yaml format)
+     *
+     * @deprecated use {@link #settings(String source, MediaType mediaType)} instead
      */
+    @Deprecated
     public CreateIndexRequest settings(String source, XContentType xContentType) {
         this.settings = Settings.builder().loadFromSource(source, xContentType).build();
         return this;
     }
 
+    /**
+     * The settings to create the index with (using a generic MediaType)
+     */
+    public CreateIndexRequest settings(String source, MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
+        return this;
+    }
+
     /**
      * Allows to set the settings using a json builder.
      */
     public CreateIndexRequest settings(XContentBuilder builder) {
-        settings(Strings.toString(builder), builder.contentType());
+        settings(builder.toString(), builder.contentType());
         return this;
     }
 
@@ -245,12 +258,38 @@ public CreateIndexRequest mapping(String mapping) {
         return this;
     }
 
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param source The mapping source
+     * @param xContentType The content type of the source
+     *
+     * @deprecated use {@link #mapping(String source, MediaType mediaType)} instead
+     */
+    @Deprecated
+    public CreateIndexRequest mapping(String source, XContentType xContentType) {
+        return mapping(new BytesArray(source), xContentType);
+    }
+
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * Note that the definition should *not* be nested under a type name.
+     *
+     * @param source The mapping source
+     * @param mediaType The media type of the source
+     */
+    public CreateIndexRequest mapping(String source, MediaType mediaType) {
+        return mapping(new BytesArray(source), mediaType);
+    }
+
     /**
      * Adds mapping that will be added when the index gets created.
      *
      * @param source The mapping source
      * @param xContentType the content type of the mapping source
-     * @deprecated types are being removed
+     *
+     * @deprecated use {@link #mapping(BytesReference source, MediaType mediaType)} instead
      */
     @Deprecated
     private CreateIndexRequest mapping(BytesReference source, XContentType xContentType) {
@@ -259,6 +298,20 @@ private CreateIndexRequest mapping(BytesReference source, XContentType xContentT
         return mapping(MapperService.SINGLE_MAPPING_NAME, mappingAsMap);
     }
 
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * Note that the definition should *not* be nested under a type name.
+     *
+     * @param source The mapping source
+     * @param mediaType The media type of the source
+     */
+    public CreateIndexRequest mapping(BytesReference source, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
+        Map<String, Object> mappingAsMap = XContentHelper.convertToMap(source, false, mediaType).v2();
+        return mapping(MapperService.SINGLE_MAPPING_NAME, mappingAsMap);
+    }
+
     /**
      * Adds mapping that will be added when the index gets created.
      *
@@ -296,7 +349,7 @@ private CreateIndexRequest mapping(String type, Map<String, ?> source) {
         try {
             XContentBuilder builder = XContentFactory.jsonBuilder();
             builder.map(source);
-            return mapping(Strings.toString(builder));
+            return mapping(builder.toString());
         } catch (IOException e) {
             throw new OpenSearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -373,11 +426,23 @@ public CreateIndexRequest alias(Alias alias) {
 
     /**
      * Sets the settings and mappings as a single source.
+     *
+     * @deprecated use {@link #source(String, MediaType)} instead
      */
+    @Deprecated
     public CreateIndexRequest source(String source, XContentType xContentType) {
         return source(new BytesArray(source), xContentType);
     }
 
+    /**
+     * Sets the settings and mappings as a single source.
+     *
+     * Note that the mapping definition should *not* be nested under a type name.
+     */
+    public CreateIndexRequest source(String source, MediaType mediaType) {
+        return source(new BytesArray(source), mediaType);
+    }
+
     /**
      * Sets the settings and mappings as a single source.
      */
@@ -387,14 +452,29 @@ public CreateIndexRequest source(XContentBuilder source) {
 
     /**
      * Sets the settings and mappings as a single source.
+     *
+     * @deprecated use {@link #source(byte[], MediaType mediaType)} instead
      */
+    @Deprecated
     public CreateIndexRequest source(byte[] source, XContentType xContentType) {
         return source(source, 0, source.length, xContentType);
     }
 
     /**
      * Sets the settings and mappings as a single source.
+     *
+     * Note that the mapping definition should *not* be nested under a type name.
      */
+    public CreateIndexRequest source(byte[] source, MediaType mediaType) {
+        return source(source, 0, source.length, mediaType);
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     *
+     * @deprecated use {@link #source(byte[], int, int, MediaType)} instead
+     */
+    @Deprecated
     public CreateIndexRequest source(byte[] source, int offset, int length, XContentType xContentType) {
         return source(new BytesArray(source, offset, length), xContentType);
     }
@@ -402,12 +482,31 @@ public CreateIndexRequest source(byte[] source, int offset, int length, XContent
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequest source(byte[] source, int offset, int length, MediaType mediaType) {
+        return source(new BytesArray(source, offset, length), mediaType);
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     *
+     * @deprecated use {@link #source(BytesReference, MediaType)} instead
+     */
+    @Deprecated
     public CreateIndexRequest source(BytesReference source, XContentType xContentType) {
         Objects.requireNonNull(xContentType);
         source(XContentHelper.convertToMap(source, false, xContentType).v2(), LoggingDeprecationHandler.INSTANCE);
         return this;
     }
 
+    /**
+     * Sets the settings and mappings as a single source.
+     */
+    public CreateIndexRequest source(BytesReference source, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
+        source(XContentHelper.convertToMap(source, false, mediaType).v2(), LoggingDeprecationHandler.INSTANCE);
+        return this;
+    }
+
     /**
      * Sets the settings and mappings as a single source.
      */
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilder.java
index cc99f63c6a844..3493ee06827c1 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilder.java
@@ -36,16 +36,19 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.util.Map;
 
 /**
  * Builder for a create index request
+ *
+ * @opensearch.internal
  */
 public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<
     CreateIndexRequest,
@@ -95,8 +98,8 @@ public CreateIndexRequestBuilder setSettings(XContentBuilder builder) {
     /**
      * The settings to create the index with (either json or yaml format)
      */
-    public CreateIndexRequestBuilder setSettings(String source, XContentType xContentType) {
-        request.settings(source, xContentType);
+    public CreateIndexRequestBuilder setSettings(String source, MediaType mediaType) {
+        request.settings(source, mediaType);
         return this;
     }
 
@@ -198,24 +201,24 @@ public CreateIndexRequestBuilder addAlias(Alias alias) {
     /**
      * Sets the settings and mappings as a single source.
      */
-    public CreateIndexRequestBuilder setSource(String source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public CreateIndexRequestBuilder setSource(String source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the settings and mappings as a single source.
      */
-    public CreateIndexRequestBuilder setSource(BytesReference source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public CreateIndexRequestBuilder setSource(BytesReference source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the settings and mappings as a single source.
      */
-    public CreateIndexRequestBuilder setSource(byte[] source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public CreateIndexRequestBuilder setSource(byte[] source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexResponse.java
index dedc022180cda..1b3ad48402eed 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/CreateIndexResponse.java
@@ -33,21 +33,23 @@
 package org.opensearch.action.admin.indices.create;
 
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A response for a create index action.
+ *
+ * @opensearch.internal
  */
 public class CreateIndexResponse extends ShardsAcknowledgedResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/TransportCreateIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/create/TransportCreateIndexAction.java
index 2269931deafc8..b5f822bd45b7e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/TransportCreateIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/TransportCreateIndexAction.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.action.admin.indices.create;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -42,7 +41,8 @@
 import org.opensearch.cluster.metadata.MetadataCreateIndexService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -50,8 +50,10 @@
 
 /**
  * Create index action.
+ *
+ * @opensearch.internal
  */
-public class TransportCreateIndexAction extends TransportMasterNodeAction<CreateIndexRequest, CreateIndexResponse> {
+public class TransportCreateIndexAction extends TransportClusterManagerNodeAction<CreateIndexRequest, CreateIndexResponse> {
 
     private final MetadataCreateIndexService createIndexService;
 
@@ -89,11 +91,17 @@ protected CreateIndexResponse read(StreamInput in) throws IOException {
 
     @Override
     protected ClusterBlockException checkBlock(CreateIndexRequest request, ClusterState state) {
-        return state.blocks().indexBlockedException(ClusterBlockLevel.METADATA_WRITE, request.index());
+        ClusterBlockException clusterBlockException = state.blocks()
+            .indexBlockedException(ClusterBlockLevel.METADATA_WRITE, request.index());
+
+        if (clusterBlockException == null) {
+            return state.blocks().createIndexBlockedException(ClusterBlockLevel.CREATE_INDEX);
+        }
+        return clusterBlockException;
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final CreateIndexRequest request,
         final ClusterState state,
         final ActionListener<CreateIndexResponse> listener
@@ -109,7 +117,7 @@ protected void masterOperation(
             indexName,
             request.index()
         ).ackTimeout(request.timeout())
-            .masterNodeTimeout(request.masterNodeTimeout())
+            .masterNodeTimeout(request.clusterManagerNodeTimeout())
             .settings(request.settings())
             .mappings(request.mappings())
             .aliases(request.aliases())
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/create/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/create/package-info.java
index e386817090285..07bdc0eaa5c64 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/create/package-info.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/create/package-info.java
@@ -25,12 +25,12 @@
  * under the License.
  */
 
-/**
- * Create index action.
- */
 /*
  * Modifications Copyright OpenSearch Contributors. See
  * GitHub history for details.
  */
 
+/**
+ * Create index action.
+ */
 package org.opensearch.action.admin.indices.create;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/DanglingIndexInfo.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/DanglingIndexInfo.java
index decca8ab4151c..47ba1cca9fc4a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/DanglingIndexInfo.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/DanglingIndexInfo.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.action.admin.indices.dangling;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
 /**
  * Contains information about a dangling index, i.e. an index that OpenSearch has found
  * on-disk but is not present in the cluster state.
+ *
+ * @opensearch.internal
  */
 public class DanglingIndexInfo implements Writeable {
     private final String nodeId;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexAction.java
index f151a3ea46465..6559ef4cd89bd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexAction.java
@@ -37,6 +37,8 @@
 
 /**
  * This action causes a dangling index to be considered as deleted by the cluster.
+ *
+ * @opensearch.internal
  */
 public class DeleteDanglingIndexAction extends ActionType<AcknowledgedResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexRequest.java
index 733fb0a24ebec..0443325f82778 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/DeleteDanglingIndexRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -43,6 +43,8 @@
 /**
  * Represents a request to delete a particular dangling index, specified by its UUID. The {@link #acceptDataLoss}
  * flag must also be explicitly set to true, or later validation will fail.
+ *
+ * @opensearch.internal
  */
 public class DeleteDanglingIndexRequest extends AcknowledgedRequest<DeleteDanglingIndexRequest> {
     private final String indexUUID;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/TransportDeleteDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/TransportDeleteDanglingIndexAction.java
index baa173a0cdf88..751a872ee7dcd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/TransportDeleteDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/TransportDeleteDanglingIndexAction.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.action.admin.indices.dangling.delete;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.admin.indices.dangling.DanglingIndexInfo;
 import org.opensearch.action.admin.indices.dangling.list.ListDanglingIndicesAction;
@@ -44,8 +42,8 @@
 import org.opensearch.action.admin.indices.dangling.list.ListDanglingIndicesResponse;
 import org.opensearch.action.admin.indices.dangling.list.NodeListDanglingIndicesResponse;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
@@ -54,11 +52,14 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -70,12 +71,17 @@
  * Implements the deletion of a dangling index. When handling a {@link DeleteDanglingIndexAction},
  * this class first checks that such a dangling index exists. It then submits a cluster state update
  * to add the index to the index graveyard.
+ *
+ * @opensearch.internal
  */
-public class TransportDeleteDanglingIndexAction extends TransportMasterNodeAction<DeleteDanglingIndexRequest, AcknowledgedResponse> {
+public class TransportDeleteDanglingIndexAction extends TransportClusterManagerNodeAction<
+    DeleteDanglingIndexRequest,
+    AcknowledgedResponse> {
     private static final Logger logger = LogManager.getLogger(TransportDeleteDanglingIndexAction.class);
 
     private final Settings settings;
     private final NodeClient nodeClient;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deleteDanglingIndexTaskKey;
 
     @Inject
     public TransportDeleteDanglingIndexAction(
@@ -98,6 +104,8 @@ public TransportDeleteDanglingIndexAction(
         );
         this.settings = settings;
         this.nodeClient = nodeClient;
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        deleteDanglingIndexTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_DANGLING_INDEX_KEY, true);
     }
 
     @Override
@@ -111,7 +119,7 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         DeleteDanglingIndexRequest deleteRequest,
         ClusterState state,
         ActionListener<AcknowledgedResponse> deleteListener
@@ -153,6 +161,11 @@ protected AcknowledgedResponse newResponse(boolean acknowledged) {
                             return new AcknowledgedResponse(acknowledged);
                         }
 
+                        @Override
+                        public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                            return deleteDanglingIndexTaskKey;
+                        }
+
                         @Override
                         public ClusterState execute(final ClusterState currentState) {
                             return deleteDanglingIndex(currentState, indexToDelete);
@@ -172,8 +185,8 @@ public void onFailure(Exception e) {
     private ClusterState deleteDanglingIndex(ClusterState currentState, Index indexToDelete) {
         final Metadata metaData = currentState.getMetadata();
 
-        for (ObjectObjectCursor<String, IndexMetadata> each : metaData.indices()) {
-            if (indexToDelete.getUUID().equals(each.value.getIndexUUID())) {
+        for (final IndexMetadata each : metaData.indices().values()) {
+            if (indexToDelete.getUUID().equals(each.getIndexUUID())) {
                 throw new IllegalArgumentException(
                     "Refusing to delete dangling index "
                         + indexToDelete
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/package-info.java
new file mode 100644
index 0000000000000..15a966b35ab55
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Delete Dangling Indices transport handlers. */
+package org.opensearch.action.admin.indices.dangling.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexAction.java
index fa55661788d3e..f308728c7a85e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Represents a request to find a particular dangling index by UUID.
+ *
+ * @opensearch.internal
  */
 public class FindDanglingIndexAction extends ActionType<FindDanglingIndexResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexRequest.java
index c5a3621bd8340..f853a47b3c2bf 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexRequest.java
@@ -33,12 +33,17 @@
 package org.opensearch.action.admin.indices.dangling.find;
 
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for finding a dangling index
+ *
+ * @opensearch.internal
+ */
 public class FindDanglingIndexRequest extends BaseNodesRequest<FindDanglingIndexRequest> {
     private final String indexUUID;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexResponse.java
index c1b1a2901e5e2..b834775be1767 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/FindDanglingIndexResponse.java
@@ -35,8 +35,8 @@
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.List;
@@ -44,6 +44,8 @@
 /**
  * Models a response to a {@link FindDanglingIndexRequest}. A find request queries every node in the
  * cluster looking for a dangling index with a specific UUID.
+ *
+ * @opensearch.internal
  */
 public class FindDanglingIndexResponse extends BaseNodesResponse<NodeFindDanglingIndexResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexRequest.java
index ddb16ec51a080..276d92c50c69c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexRequest.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.admin.indices.dangling.find;
 
-import java.io.IOException;
-
 import org.opensearch.action.support.nodes.BaseNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
 
 /**
  * Used when querying every node in the cluster for a specific dangling index.
+ *
+ * @opensearch.internal
  */
 public class NodeFindDanglingIndexRequest extends BaseNodeRequest {
     private final String indexUUID;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexResponse.java
index 0f21db3eb7a91..41504a436750a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/NodeFindDanglingIndexResponse.java
@@ -35,14 +35,16 @@
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.List;
 
 /**
  * Used when querying every node in the cluster for a specific dangling index.
+ *
+ * @opensearch.internal
  */
 public class NodeFindDanglingIndexResponse extends BaseNodeResponse {
     /**
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/TransportFindDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/TransportFindDanglingIndexAction.java
index 0da65f79db2af..13da03a04acbd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/TransportFindDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/TransportFindDanglingIndexAction.java
@@ -32,10 +32,6 @@
 
 package org.opensearch.action.admin.indices.dangling.find;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.nodes.TransportNodesAction;
@@ -43,13 +39,19 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.gateway.DanglingIndicesState;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Finds a specified dangling index by its UUID, searching across all nodes.
+ *
+ * @opensearch.internal
  */
 public class TransportFindDanglingIndexAction extends TransportNodesAction<
     FindDanglingIndexRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/package-info.java
new file mode 100644
index 0000000000000..d5536d5794f3c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/find/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Find Dangling Indices transport handlers. */
+package org.opensearch.action.admin.indices.dangling.find;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexAction.java
index 1f6bbdecc7c12..5f7a096b1d749 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexAction.java
@@ -37,6 +37,8 @@
 
 /**
  * Represents a request to import a particular dangling index.
+ *
+ * @opensearch.internal
  */
 public class ImportDanglingIndexAction extends ActionType<AcknowledgedResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexRequest.java
index b154d048a10d6..590f08a82c1d2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/ImportDanglingIndexRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -45,6 +45,8 @@
  * Represents a request to import a particular dangling index, specified
  * by its UUID. The {@link #acceptDataLoss} flag must also be
  * explicitly set to true, or later validation will fail.
+ *
+ * @opensearch.internal
  */
 public class ImportDanglingIndexRequest extends AcknowledgedRequest<ImportDanglingIndexRequest> {
     private final String indexUUID;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/TransportImportDanglingIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/TransportImportDanglingIndexAction.java
index c648f9eea837a..3f47d1bf083f4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/TransportImportDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/TransportImportDanglingIndexAction.java
@@ -32,17 +32,9 @@
 
 package org.opensearch.action.admin.indices.dangling.import_index;
 
-import static java.util.Collections.singletonList;
-
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.List;
-import java.util.stream.Collectors;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.admin.indices.dangling.find.FindDanglingIndexAction;
 import org.opensearch.action.admin.indices.dangling.find.FindDanglingIndexRequest;
@@ -54,14 +46,24 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.gateway.LocalAllocateDangledIndices;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.singletonList;
+
 /**
  * Implements the import of a dangling index. When handling a {@link ImportDanglingIndexAction},
  * this class first checks that such a dangling index exists. It then calls {@link LocalAllocateDangledIndices}
  * to perform the actual allocation.
+ *
+ * @opensearch.internal
  */
 public class TransportImportDanglingIndexAction extends HandledTransportAction<ImportDanglingIndexRequest, AcknowledgedResponse> {
     private static final Logger logger = LogManager.getLogger(TransportImportDanglingIndexAction.class);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/package-info.java
new file mode 100644
index 0000000000000..fce0f5a130c2f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/import_index/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Import Dangling Index transport handler. */
+package org.opensearch.action.admin.indices.dangling.import_index;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesAction.java
index 0e797ca930400..d8ace959c61d3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Represents a request to list all dangling indices known to the cluster.
+ *
+ * @opensearch.internal
  */
 public class ListDanglingIndicesAction extends ActionType<ListDanglingIndicesResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesRequest.java
index 6c2bd386119a2..adbfe9b760ed8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesRequest.java
@@ -33,12 +33,17 @@
 package org.opensearch.action.admin.indices.dangling.list;
 
 import org.opensearch.action.support.nodes.BaseNodesRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for listing a dangling indices
+ *
+ * @opensearch.internal
+ */
 public class ListDanglingIndicesRequest extends BaseNodesRequest<ListDanglingIndicesRequest> {
     /**
      * Filter the response by index UUID. Leave as null to find all indices.
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesResponse.java
index d412d3e323d68..0cff01af536dc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/ListDanglingIndicesResponse.java
@@ -36,12 +36,12 @@
 import org.opensearch.action.admin.indices.dangling.DanglingIndexInfo;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -57,6 +57,8 @@
  * cluster and aggregates their responses. When the aggregated response is converted to {@link XContent},
  * information for each dangling index is presented under the "dangling_indices" key. If any nodes
  * in the cluster failed to answer, the details are presented under the "_nodes.failures" key.
+ *
+ * @opensearch.internal
  */
 public class ListDanglingIndicesResponse extends BaseNodesResponse<NodeListDanglingIndicesResponse> implements StatusToXContentObject {
 
@@ -126,7 +128,13 @@ protected void writeNodesTo(StreamOutput out, List<NodeListDanglingIndicesRespon
         out.writeList(nodes);
     }
 
-    // visible for testing
+    /**
+     * Aggregates dangling index information
+     *
+     * NOTE: visible for testing
+     *
+     * @opensearch.internal
+     */
     static class AggregatedDanglingIndexInfo {
         private final String indexUUID;
         private final String indexName;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesRequest.java
index ad0ed102145b5..a80b610b5b776 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesRequest.java
@@ -33,13 +33,15 @@
 package org.opensearch.action.admin.indices.dangling.list;
 
 import org.opensearch.action.support.nodes.BaseNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Used when querying every node in the cluster for dangling indices, in response to a list request.
+ *
+ * @opensearch.internal
  */
 public class NodeListDanglingIndicesRequest extends BaseNodeRequest {
     /**
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesResponse.java
index 3495a028af3c0..338f2f79235b8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/NodeListDanglingIndicesResponse.java
@@ -35,14 +35,16 @@
 import org.opensearch.action.admin.indices.dangling.DanglingIndexInfo;
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.List;
 
 /**
  * Used when querying every node in the cluster for dangling indices, in response to a list request.
+ *
+ * @opensearch.internal
  */
 public class NodeListDanglingIndicesResponse extends BaseNodeResponse {
     private final List<DanglingIndexInfo> indexMetaData;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/TransportListDanglingIndicesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/TransportListDanglingIndicesAction.java
index 1274010bfb8a2..59076cc6ef8fb 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/TransportListDanglingIndicesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/TransportListDanglingIndicesAction.java
@@ -40,7 +40,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.gateway.DanglingIndicesState;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -52,6 +52,8 @@
 /**
  * Implements the listing of all dangling indices. All nodes in the cluster are queried, and
  * their answers aggregated. Finding dangling indices is performed in {@link DanglingIndicesState}.
+ *
+ * @opensearch.internal
  */
 public class TransportListDanglingIndicesAction extends TransportNodesAction<
     ListDanglingIndicesRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/package-info.java
new file mode 100644
index 0000000000000..f6c37345fb73c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/list/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** List Dangling Indices transport handler. */
+package org.opensearch.action.admin.indices.dangling.list;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/dangling/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/dangling/package-info.java
index e97ff628d8d79..e69b6acf995e3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/dangling/package-info.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/dangling/package-info.java
@@ -25,6 +25,11 @@
  * under the License.
  */
 
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
 /**
  * Dangling indices are indices that exist on disk on one or more nodes but
  * which do not currently exist in the cluster state. They arise in a
@@ -33,17 +38,13 @@
  * <ul>
  * <li>A user overflows the index graveyard by deleting more than 500 indices while a node is offline and then the node rejoins the
  * cluster</li>
- * <li>A node (unsafely) moves from one cluster to another, perhaps because the original cluster lost all its master nodes</li>
+ * <li>A node (unsafely) moves from one cluster to another, perhaps because the original cluster lost all its cluster-manager nodes</li>
  * <li>A user (unsafely) meddles with the contents of the data path, maybe restoring an old index folder from a backup</li>
  * <li>A disk partially fails and the user has no replicas and no snapshots and wants to (unsafely) recover whatever they can</li>
- * <li>A cluster loses all master nodes and those are (unsafely) restored from backup, but the backup does not contain the index</li>
+ * <li>A cluster loses all cluster-manager nodes and those are (unsafely) restored from backup, but the backup does not contain the index</li>
  * </ul>
  *
  * <p>The classes in this package form an API for managing dangling indices, allowing them to be listed, imported or deleted.
  */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
 
 package org.opensearch.action.admin.indices.dangling;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamAction.java b/server/src/main/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamAction.java
index 6c5c417825abf..14b29c4b2bbba 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamAction.java
@@ -31,16 +31,15 @@
 
 package org.opensearch.action.admin.indices.datastream;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -48,16 +47,22 @@
 import org.opensearch.cluster.metadata.MetadataCreateDataStreamService;
 import org.opensearch.cluster.metadata.MetadataCreateDataStreamService.CreateDataStreamClusterStateUpdateRequest;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport action for creating a datastream
+ *
+ * @opensearch.internal
+ */
 public class CreateDataStreamAction extends ActionType<AcknowledgedResponse> {
 
     public static final CreateDataStreamAction INSTANCE = new CreateDataStreamAction();
@@ -67,6 +72,11 @@ private CreateDataStreamAction() {
         super(NAME, AcknowledgedResponse::new);
     }
 
+    /**
+     * Request for Creating Data Stream
+     *
+     * @opensearch.internal
+     */
     public static class Request extends AcknowledgedRequest<Request> implements IndicesRequest {
 
         private final String name;
@@ -119,7 +129,12 @@ public IndicesOptions indicesOptions() {
         }
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, AcknowledgedResponse> {
+    /**
+     * Transport Action for Creating Data Stream
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, AcknowledgedResponse> {
 
         private final MetadataCreateDataStreamService metadataCreateDataStreamService;
 
@@ -147,11 +162,11 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
         }
 
         @Override
-        protected void masterOperation(Request request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
+        protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
             throws Exception {
             CreateDataStreamClusterStateUpdateRequest updateRequest = new CreateDataStreamClusterStateUpdateRequest(
                 request.name,
-                request.masterNodeTimeout(),
+                request.clusterManagerNodeTimeout(),
                 request.timeout()
             );
             metadataCreateDataStreamService.createDataStream(updateRequest, listener);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsAction.java
index cca6b83015ecc..fcb13f4091638 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsAction.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.index.PointValues;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
@@ -52,12 +51,13 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.IndexShard;
@@ -78,6 +78,11 @@
 import java.util.SortedMap;
 import java.util.stream.Stream;
 
+/**
+ * Transport action for retrieving datastream stats
+ *
+ * @opensearch.internal
+ */
 public class DataStreamsStatsAction extends ActionType<DataStreamsStatsAction.Response> {
 
     public static final DataStreamsStatsAction INSTANCE = new DataStreamsStatsAction();
@@ -87,6 +92,11 @@ public DataStreamsStatsAction() {
         super(NAME, DataStreamsStatsAction.Response::new);
     }
 
+    /**
+     * Request for Data Streams Stats
+     *
+     * @opensearch.internal
+     */
     public static class Request extends BroadcastRequest<Request> {
         public Request() {
             super((String[]) null);
@@ -97,6 +107,11 @@ public Request(StreamInput in) throws IOException {
         }
     }
 
+    /**
+     * Response for Data Streams Stats
+     *
+     * @opensearch.internal
+     */
     public static class Response extends BroadcastResponse {
         private final int dataStreamCount;
         private final int backingIndices;
@@ -198,6 +213,11 @@ public String toString() {
         }
     }
 
+    /**
+     * The Data Streams Stats container
+     *
+     * @opensearch.internal
+     */
     public static class DataStreamStats implements ToXContentObject, Writeable {
         private final String dataStream;
         private final int backingIndices;
@@ -289,6 +309,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Per Shard Data Stream stats
+     *
+     * @opensearch.internal
+     */
     public static class DataStreamShardStats implements Writeable {
         private final ShardRouting shardRouting;
         private final StoreStats storeStats;
@@ -326,12 +351,22 @@ public long getMaxTimestamp() {
         }
     }
 
+    /**
+     * Aggregated data Stream stats
+     *
+     * @opensearch.internal
+     */
     private static class AggregatedStats {
         Set<String> backingIndices = new HashSet<>();
         long storageBytes = 0L;
         long maxTimestamp = 0L;
     }
 
+    /**
+     * Transport Action for Data Stream Stats
+     *
+     * @opensearch.internal
+     */
     public static class TransportAction extends TransportBroadcastByNodeAction<Request, Response, DataStreamShardStats> {
 
         private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamAction.java b/server/src/main/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamAction.java
index 5d79f51cbab65..190194e071bc4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamAction.java
@@ -33,15 +33,14 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -50,16 +49,19 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataDeleteIndexService;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
 import org.opensearch.snapshots.SnapshotInProgressException;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.threadpool.ThreadPool;
@@ -73,6 +75,11 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport action for deleting a datastream
+ *
+ * @opensearch.internal
+ */
 public class DeleteDataStreamAction extends ActionType<AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(DeleteDataStreamAction.class);
@@ -84,7 +91,12 @@ private DeleteDataStreamAction() {
         super(NAME, AcknowledgedResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> implements IndicesRequest.Replaceable {
+    /**
+     * Request for deleting data streams
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> implements IndicesRequest.Replaceable {
 
         private String[] names;
 
@@ -149,9 +161,15 @@ public IndicesRequest indices(String... indices) {
         }
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, AcknowledgedResponse> {
+    /**
+     * Transport action for deleting data streams
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, AcknowledgedResponse> {
 
         private final MetadataDeleteIndexService deleteIndexService;
+        private final ClusterManagerTaskThrottler.ThrottlingKey removeDataStreamTaskKey;
 
         @Inject
         public TransportAction(
@@ -164,6 +182,8 @@ public TransportAction(
         ) {
             super(NAME, transportService, clusterService, threadPool, actionFilters, Request::new, indexNameExpressionResolver);
             this.deleteIndexService = deleteIndexService;
+            // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+            removeDataStreamTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.REMOVE_DATA_STREAM_KEY, true);
         }
 
         @Override
@@ -177,7 +197,7 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
         }
 
         @Override
-        protected void masterOperation(Request request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
+        protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
             throws Exception {
             clusterService.submitStateUpdateTask(
                 "remove-data-stream [" + Strings.arrayToCommaDelimitedString(request.names) + "]",
@@ -185,7 +205,7 @@ protected void masterOperation(Request request, ClusterState state, ActionListen
 
                     @Override
                     public TimeValue timeout() {
-                        return request.masterNodeTimeout();
+                        return request.clusterManagerNodeTimeout();
                     }
 
                     @Override
@@ -193,6 +213,11 @@ public void onFailure(String source, Exception e) {
                         listener.onFailure(e);
                     }
 
+                    @Override
+                    public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                        return removeDataStreamTaskKey;
+                    }
+
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return removeDataStream(deleteIndexService, currentState, request);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/datastream/GetDataStreamAction.java b/server/src/main/java/org/opensearch/action/admin/indices/datastream/GetDataStreamAction.java
index d519c80f6d6c2..6a7967d31653c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/datastream/GetDataStreamAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/datastream/GetDataStreamAction.java
@@ -33,15 +33,13 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -53,14 +51,16 @@
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -73,6 +73,11 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
+/**
+ * Transport action for getting a datastream
+ *
+ * @opensearch.internal
+ */
 public class GetDataStreamAction extends ActionType<GetDataStreamAction.Response> {
 
     public static final GetDataStreamAction INSTANCE = new GetDataStreamAction();
@@ -82,7 +87,12 @@ private GetDataStreamAction() {
         super(NAME, Response::new);
     }
 
-    public static class Request extends MasterNodeReadRequest<Request> implements IndicesRequest.Replaceable {
+    /**
+     * Request for getting data streams
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeReadRequest<Request> implements IndicesRequest.Replaceable {
 
         private String[] names;
 
@@ -143,9 +153,19 @@ public IndicesRequest indices(String... indices) {
         }
     }
 
+    /**
+     * Response for getting data streams
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse implements ToXContentObject {
         public static final ParseField DATASTREAMS_FIELD = new ParseField("data_streams");
 
+        /**
+         * Data streams information
+         *
+         * @opensearch.internal
+         */
         public static class DataStreamInfo extends AbstractDiffable<DataStreamInfo> implements ToXContentObject {
 
             public static final ParseField STATUS_FIELD = new ParseField("status");
@@ -262,7 +282,12 @@ public int hashCode() {
         }
     }
 
-    public static class TransportAction extends TransportMasterNodeReadAction<Request, Response> {
+    /**
+     * Transport Action for getting data streams
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeReadAction<Request, Response> {
 
         private static final Logger logger = LogManager.getLogger(TransportAction.class);
 
@@ -288,7 +313,7 @@ protected Response read(StreamInput in) throws IOException {
         }
 
         @Override
-        protected void masterOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
+        protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
             List<DataStream> dataStreams = getDataStreams(state, indexNameExpressionResolver, request);
             List<Response.DataStreamInfo> dataStreamInfos = new ArrayList<>(dataStreams.size());
             for (DataStream dataStream : dataStreams) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/datastream/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/datastream/package-info.java
new file mode 100644
index 0000000000000..a37c2bed1adff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/datastream/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Data Stream transport handlers. */
+package org.opensearch.action.admin.indices.datastream;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexAction.java
index 6f0dd781b4cec..696c1244c7504 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for deleting an index
+ *
+ * @opensearch.internal
+ */
 public class DeleteIndexAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeleteIndexAction INSTANCE = new DeleteIndexAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexClusterStateUpdateRequest.java
index a6d06833ebae9..5088d021ca9b8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexClusterStateUpdateRequest.java
@@ -35,6 +35,8 @@
 
 /**
  * Cluster state update request that allows to close one or more indices
+ *
+ * @opensearch.internal
  */
 public class DeleteIndexClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<DeleteIndexClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequest.java
index c29072b135b85..006da6b3cbb09 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequest.java
@@ -36,9 +36,9 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
 
@@ -46,6 +46,8 @@
 
 /**
  * A request to delete an index. Best created with {@link org.opensearch.client.Requests#deleteIndexRequest(String)}.
+ *
+ * @opensearch.internal
  */
 public class DeleteIndexRequest extends AcknowledgedRequest<DeleteIndexRequest> implements IndicesRequest.Replaceable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequestBuilder.java
index 741f46d44d8b7..33f6342e94139 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/delete/DeleteIndexRequestBuilder.java
@@ -37,6 +37,11 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for deleting an index
+ *
+ * @opensearch.internal
+ */
 public class DeleteIndexRequestBuilder extends AcknowledgedRequestBuilder<
     DeleteIndexRequest,
     AcknowledgedResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/delete/TransportDeleteIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/delete/TransportDeleteIndexAction.java
index ec8c0fe8ed011..51c90a982e71b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/delete/TransportDeleteIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/delete/TransportDeleteIndexAction.java
@@ -35,11 +35,10 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.DestructiveOperations;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -47,8 +46,9 @@
 import org.opensearch.cluster.metadata.MetadataDeleteIndexService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -60,8 +60,10 @@
 
 /**
  * Delete index action.
+ *
+ * @opensearch.internal
  */
-public class TransportDeleteIndexAction extends TransportMasterNodeAction<DeleteIndexRequest, AcknowledgedResponse> {
+public class TransportDeleteIndexAction extends TransportClusterManagerNodeAction<DeleteIndexRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportDeleteIndexAction.class);
 
@@ -113,7 +115,7 @@ protected ClusterBlockException checkBlock(DeleteIndexRequest request, ClusterSt
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteIndexRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -125,7 +127,7 @@ protected void masterOperation(
         }
 
         DeleteIndexClusterStateUpdateRequest deleteRequest = new DeleteIndexClusterStateUpdateRequest().ackTimeout(request.timeout())
-            .masterNodeTimeout(request.masterNodeTimeout())
+            .masterNodeTimeout(request.clusterManagerNodeTimeout())
             .indices(concreteIndices.toArray(new Index[concreteIndices.size()]));
 
         deleteIndexService.deleteIndices(deleteRequest, new ActionListener<ClusterStateUpdateResponse>() {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsAction.java
index 1eae6b99bc1ee..6bd0cddc00d07 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for checking if an index exists
+ *
+ * @opensearch.internal
+ */
 public class IndicesExistsAction extends ActionType<IndicesExistsResponse> {
 
     public static final IndicesExistsAction INSTANCE = new IndicesExistsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequest.java
index d511c18f5505e..f9bd849e549b7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequest.java
@@ -35,16 +35,21 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
-public class IndicesExistsRequest extends MasterNodeReadRequest<IndicesExistsRequest> implements IndicesRequest.Replaceable {
+/**
+ * Transport request for checking if an index exists
+ *
+ * @opensearch.internal
+ */
+public class IndicesExistsRequest extends ClusterManagerNodeReadRequest<IndicesExistsRequest> implements IndicesRequest.Replaceable {
 
     private String[] indices = Strings.EMPTY_ARRAY;
     private IndicesOptions indicesOptions = IndicesOptions.fromOptions(false, false, true, true);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequestBuilder.java
index bb38d14530588..8459bbd8b874e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsRequestBuilder.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.action.admin.indices.exists.indices;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class IndicesExistsRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for checking if an index exists
+ *
+ * @opensearch.internal
+ */
+public class IndicesExistsRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     IndicesExistsRequest,
     IndicesExistsResponse,
     IndicesExistsRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsResponse.java
index 336bb6147d07d..4ac85492229f0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/IndicesExistsResponse.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.action.admin.indices.exists.indices;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport response for checking if an index exists
+ *
+ * @opensearch.internal
+ */
 public class IndicesExistsResponse extends ActionResponse {
 
     private boolean exists;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/TransportIndicesExistsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/TransportIndicesExistsAction.java
index 076e2ecc2c119..428a0eb35513d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/TransportIndicesExistsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/TransportIndicesExistsAction.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.action.admin.indices.exists.indices;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -51,8 +51,10 @@
 
 /**
  * Indices exists action.
+ *
+ * @opensearch.internal
  */
-public class TransportIndicesExistsAction extends TransportMasterNodeReadAction<IndicesExistsRequest, IndicesExistsResponse> {
+public class TransportIndicesExistsAction extends TransportClusterManagerNodeReadAction<IndicesExistsRequest, IndicesExistsResponse> {
 
     @Inject
     public TransportIndicesExistsAction(
@@ -101,7 +103,7 @@ protected ClusterBlockException checkBlock(IndicesExistsRequest request, Cluster
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final IndicesExistsRequest request,
         final ClusterState state,
         final ActionListener<IndicesExistsResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/package-info.java
new file mode 100644
index 0000000000000..e5b320dc1bdcd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/indices/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Exists transport handler. */
+package org.opensearch.action.admin.indices.exists.indices;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/package-info.java
new file mode 100644
index 0000000000000..0a91ac2fd9a20
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/exists/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Exists transport handlers. */
+package org.opensearch.action.admin.indices.exists;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TransportTypesExistsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TransportTypesExistsAction.java
deleted file mode 100644
index bf4e0375941e7..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TransportTypesExistsAction.java
+++ /dev/null
@@ -1,125 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.exists.types;
-
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.TransportService;
-
-import java.io.IOException;
-
-/**
- * Types exists transport action.
- */
-public class TransportTypesExistsAction extends TransportMasterNodeReadAction<TypesExistsRequest, TypesExistsResponse> {
-
-    @Inject
-    public TransportTypesExistsAction(
-        TransportService transportService,
-        ClusterService clusterService,
-        ThreadPool threadPool,
-        ActionFilters actionFilters,
-        IndexNameExpressionResolver indexNameExpressionResolver
-    ) {
-        super(
-            TypesExistsAction.NAME,
-            transportService,
-            clusterService,
-            threadPool,
-            actionFilters,
-            TypesExistsRequest::new,
-            indexNameExpressionResolver
-        );
-    }
-
-    @Override
-    protected String executor() {
-        // lightweight check
-        return ThreadPool.Names.SAME;
-    }
-
-    @Override
-    protected TypesExistsResponse read(StreamInput in) throws IOException {
-        return new TypesExistsResponse(in);
-    }
-
-    @Override
-    protected ClusterBlockException checkBlock(TypesExistsRequest request, ClusterState state) {
-        return state.blocks()
-            .indicesBlockedException(ClusterBlockLevel.METADATA_READ, indexNameExpressionResolver.concreteIndexNames(state, request));
-    }
-
-    @Override
-    protected void masterOperation(
-        final TypesExistsRequest request,
-        final ClusterState state,
-        final ActionListener<TypesExistsResponse> listener
-    ) {
-        String[] concreteIndices = indexNameExpressionResolver.concreteIndexNames(state, request.indicesOptions(), request.indices());
-        if (concreteIndices.length == 0) {
-            listener.onResponse(new TypesExistsResponse(false));
-            return;
-        }
-
-        for (String concreteIndex : concreteIndices) {
-            if (!state.metadata().hasConcreteIndex(concreteIndex)) {
-                listener.onResponse(new TypesExistsResponse(false));
-                return;
-            }
-
-            MappingMetadata mapping = state.metadata().getIndices().get(concreteIndex).mapping();
-            if (mapping == null) {
-                listener.onResponse(new TypesExistsResponse(false));
-                return;
-            }
-
-            for (String type : request.types()) {
-                if (mapping.type().equals(type) == false) {
-                    listener.onResponse(new TypesExistsResponse(false));
-                    return;
-                }
-            }
-        }
-
-        listener.onResponse(new TypesExistsResponse(true));
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsAction.java
deleted file mode 100644
index df461559dda7c..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsAction.java
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.exists.types;
-
-import org.opensearch.action.ActionType;
-
-public class TypesExistsAction extends ActionType<TypesExistsResponse> {
-
-    public static final TypesExistsAction INSTANCE = new TypesExistsAction();
-    public static final String NAME = "indices:admin/types/exists";
-
-    private TypesExistsAction() {
-        super(NAME, TypesExistsResponse::new);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequest.java
deleted file mode 100644
index eee8076a9b176..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequest.java
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.exists.types;
-
-import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.IndicesRequest;
-import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-
-import java.io.IOException;
-
-import static org.opensearch.action.ValidateActions.addValidationError;
-
-public class TypesExistsRequest extends MasterNodeReadRequest<TypesExistsRequest> implements IndicesRequest.Replaceable {
-
-    private String[] indices;
-    private String[] types;
-
-    private IndicesOptions indicesOptions = IndicesOptions.strictExpandOpen();
-
-    public TypesExistsRequest() {}
-
-    public TypesExistsRequest(String[] indices, String... types) {
-        this.indices = indices;
-        this.types = types;
-    }
-
-    public TypesExistsRequest(StreamInput in) throws IOException {
-        super(in);
-        indices = in.readStringArray();
-        types = in.readStringArray();
-        indicesOptions = IndicesOptions.readIndicesOptions(in);
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        out.writeStringArray(indices);
-        out.writeStringArray(types);
-        indicesOptions.writeIndicesOptions(out);
-    }
-
-    @Override
-    public String[] indices() {
-        return indices;
-    }
-
-    @Override
-    public TypesExistsRequest indices(String... indices) {
-        this.indices = indices;
-        return this;
-    }
-
-    public String[] types() {
-        return types;
-    }
-
-    public void types(String[] types) {
-        this.types = types;
-    }
-
-    @Override
-    public IndicesOptions indicesOptions() {
-        return indicesOptions;
-    }
-
-    public TypesExistsRequest indicesOptions(IndicesOptions indicesOptions) {
-        this.indicesOptions = indicesOptions;
-        return this;
-    }
-
-    @Override
-    public ActionRequestValidationException validate() {
-        ActionRequestValidationException validationException = null;
-        if (indices == null) { // Specifying '*' via rest api results in an empty array
-            validationException = addValidationError("index/indices is missing", validationException);
-        }
-        if (types == null || types.length == 0) {
-            validationException = addValidationError("type/types is missing", validationException);
-        }
-
-        return validationException;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequestBuilder.java
deleted file mode 100644
index 12ed1b5766775..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsRequestBuilder.java
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.exists.types;
-
-import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
-import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.Strings;
-
-/**
- * A builder for {@link TypesExistsRequest}.
- */
-@Deprecated
-public class TypesExistsRequestBuilder extends MasterNodeReadOperationRequestBuilder<
-    TypesExistsRequest,
-    TypesExistsResponse,
-    TypesExistsRequestBuilder> {
-
-    /**
-     * @param indices What indices to check for types
-     */
-    public TypesExistsRequestBuilder(OpenSearchClient client, TypesExistsAction action, String... indices) {
-        super(client, action, new TypesExistsRequest(indices, Strings.EMPTY_ARRAY));
-    }
-
-    TypesExistsRequestBuilder(OpenSearchClient client, TypesExistsAction action) {
-        super(client, action, new TypesExistsRequest());
-    }
-
-    /**
-     * @param indices What indices to check for types
-     */
-    public TypesExistsRequestBuilder setIndices(String[] indices) {
-        request.indices(indices);
-        return this;
-    }
-
-    /**
-     * @param types The types to check if they exist
-     */
-    public TypesExistsRequestBuilder setTypes(String... types) {
-        request.types(types);
-        return this;
-    }
-
-    /**
-     * @param indicesOptions Specifies how to resolve indices that aren't active / ready and indices wildcard expressions
-     */
-    public TypesExistsRequestBuilder setIndicesOptions(IndicesOptions indicesOptions) {
-        request.indicesOptions(indicesOptions);
-        return this;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsResponse.java
deleted file mode 100644
index d7e08b5c9cdc9..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/exists/types/TypesExistsResponse.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.exists.types;
-
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-
-import java.io.IOException;
-
-/**
- * Whether all of the existed types exist.
- */
-public class TypesExistsResponse extends ActionResponse {
-
-    private boolean exists;
-
-    TypesExistsResponse(StreamInput in) throws IOException {
-        super(in);
-        exists = in.readBoolean();
-    }
-
-    public TypesExistsResponse(boolean exists) {
-        this.exists = exists;
-    }
-
-    public boolean isExists() {
-        return this.exists;
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeBoolean(exists);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushAction.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushAction.java
index ace63f2346e30..288a46977521e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for flushing one or more indices
+ *
+ * @opensearch.internal
+ */
 public class FlushAction extends ActionType<FlushResponse> {
 
     public static final FlushAction INSTANCE = new FlushAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequest.java
index 1020a0cfb33a9..c8b28efc5f294 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequest.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -51,6 +51,8 @@
  * @see org.opensearch.client.Requests#flushRequest(String...)
  * @see org.opensearch.client.IndicesAdminClient#flush(FlushRequest)
  * @see FlushResponse
+ *
+ * @opensearch.internal
  */
 public class FlushRequest extends BroadcastRequest<FlushRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequestBuilder.java
index c72a55b1f8519..d0cbd1d27fba6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for flushing one or more indices
+ *
+ * @opensearch.internal
+ */
 public class FlushRequestBuilder extends BroadcastOperationRequestBuilder<FlushRequest, FlushResponse, FlushRequestBuilder> {
 
     public FlushRequestBuilder(OpenSearchClient client, FlushAction action) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushResponse.java
index 9ab04dfe8c081..4135654e66271 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/FlushResponse.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.indices.flush;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -44,6 +44,8 @@
 
 /**
  * A response to flush action.
+ *
+ * @opensearch.internal
  */
 public class FlushResponse extends BroadcastResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/ShardFlushRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/ShardFlushRequest.java
index d49bf04af623b..ab6e99064b43c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/ShardFlushRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/ShardFlushRequest.java
@@ -34,12 +34,17 @@
 
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.replication.ReplicationRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Transport request for flushing one or more indices
+ *
+ * @opensearch.internal
+ */
 public class ShardFlushRequest extends ReplicationRequest<ShardFlushRequest> {
 
     private final FlushRequest request;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportFlushAction.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportFlushAction.java
index 552f88400a87d..07434c65862b6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportFlushAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportFlushAction.java
@@ -33,19 +33,21 @@
 package org.opensearch.action.admin.indices.flush;
 
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.action.support.replication.TransportBroadcastReplicationAction;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.TransportService;
 
 import java.util.List;
 
 /**
  * Flush ActionType.
+ *
+ * @opensearch.internal
  */
 public class TransportFlushAction extends TransportBroadcastReplicationAction<
     FlushRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportShardFlushAction.java b/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportShardFlushAction.java
index 53e774306e746..90db53af72257 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportShardFlushAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/flush/TransportShardFlushAction.java
@@ -33,18 +33,18 @@
 package org.opensearch.action.admin.indices.flush;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -55,6 +55,11 @@
 
 import java.io.IOException;
 
+/**
+ * Transport action for flushing one or more indices
+ *
+ * @opensearch.internal
+ */
 public class TransportShardFlushAction extends TransportReplicationAction<ShardFlushRequest, ShardFlushRequest, ReplicationResponse> {
 
     public static final String NAME = FlushAction.NAME + "[s]";
@@ -120,6 +125,11 @@ protected void shardOperationOnReplica(ShardFlushRequest request, IndexShard rep
     // TODO: Remove this transition in OpenSearch 3.0
     private static final String PRE_SYNCED_FLUSH_ACTION_NAME = "internal:indices/flush/synced/pre";
 
+    /**
+     * A Pre Shard Synced Flush Request
+     *
+     * @opensearch.internal
+     */
     private static class PreShardSyncedFlushRequest extends TransportRequest {
         private final ShardId shardId;
 
@@ -141,6 +151,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Pre synced flush handler for the transport layer
+     *
+     * @opensearch.internal
+     */
     private static final class PreSyncedFlushTransportHandler implements TransportRequestHandler<PreShardSyncedFlushRequest> {
         private final IndicesService indicesService;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeAction.java
index 07b337e61323e..06b639fadc1c7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to request force merging the segments of one or more indices.
+ *
+ * @opensearch.internal
+ */
 public class ForceMergeAction extends ActionType<ForceMergeResponse> {
 
     public static final ForceMergeAction INSTANCE = new ForceMergeAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequest.java
index 605f39ffd1312..7151d5dd64283 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequest.java
@@ -37,8 +37,8 @@
 import org.opensearch.action.support.broadcast.BroadcastRequest;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -54,9 +54,16 @@
  * @see org.opensearch.client.Requests#forceMergeRequest(String...)
  * @see org.opensearch.client.IndicesAdminClient#forceMerge(ForceMergeRequest)
  * @see ForceMergeResponse
+ *
+ * @opensearch.internal
  */
 public class ForceMergeRequest extends BroadcastRequest<ForceMergeRequest> {
 
+    /**
+     * Defaults for the Force Merge Request
+     *
+     * @opensearch.internal
+     */
     public static final class Defaults {
         public static final int MAX_NUM_SEGMENTS = -1;
         public static final boolean ONLY_EXPUNGE_DELETES = false;
@@ -76,6 +83,8 @@ public static final class Defaults {
     @Nullable
     private final String forceMergeUUID;
 
+    private boolean shouldStoreResult;
+
     /**
      * Constructs a merge request over one or more indices.
      *
@@ -156,6 +165,18 @@ public ForceMergeRequest flush(boolean flush) {
         return this;
     }
 
+    /**
+     * Should this task store its result after it has finished?
+     */
+    public void setShouldStoreResult(boolean shouldStoreResult) {
+        this.shouldStoreResult = shouldStoreResult;
+    }
+
+    @Override
+    public boolean getShouldStoreResult() {
+        return shouldStoreResult;
+    }
+
     @Override
     public String getDescription() {
         return "Force-merge indices "
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequestBuilder.java
index 2d0e7d4401a01..cff05f194cac4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeRequestBuilder.java
@@ -41,6 +41,8 @@
  * {@link #setMaxNumSegments(int)} allows to control the number of segments to force
  * merge down to. By default, will cause the force merge process to merge down
  * to half the configured number of segments.
+ *
+ * @opensearch.internal
  */
 public class ForceMergeRequestBuilder extends BroadcastOperationRequestBuilder<
     ForceMergeRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponse.java
index c898dad8bcdc9..c5316f3375ad5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponse.java
@@ -32,18 +32,22 @@
 
 package org.opensearch.action.admin.indices.forcemerge;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import static java.lang.Math.min;
+
 /**
  * A response for force merge action.
+ *
+ * @opensearch.internal
  */
 public class ForceMergeResponse extends BroadcastResponse {
 
@@ -76,4 +80,15 @@ public class ForceMergeResponse extends BroadcastResponse {
     public static ForceMergeResponse fromXContent(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append(getClass().getSimpleName()).append("[");
+        builder.append("total_shards=").append(getTotalShards()).append(',');
+        builder.append("successful_shards=").append(getSuccessfulShards()).append(',');
+        builder.append("failed_shards=").append(getFailedShards()).append(',');
+        builder.append("failures=").append(Arrays.asList(getShardFailures()).subList(0, min(3, getShardFailures().length)));
+        return builder.append(']').toString();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/TransportForceMergeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/TransportForceMergeAction.java
index 22f4b912cbe0b..fb8eb86c12269 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/TransportForceMergeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/forcemerge/TransportForceMergeAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.admin.indices.forcemerge;
 
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -43,7 +42,8 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
@@ -54,6 +54,8 @@
 
 /**
  * ForceMerge index/indices action.
+ *
+ * @opensearch.internal
  */
 public class TransportForceMergeAction extends TransportBroadcastByNodeAction<
     ForceMergeRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexAction.java
index 6d5875a012b91..92200c71ef685 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to get information about an index.
+ *
+ * @opensearch.internal
+ */
 public class GetIndexAction extends ActionType<GetIndexResponse> {
 
     public static final GetIndexAction INSTANCE = new GetIndexAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequest.java
index e1e0b2c54c904..0b2084865e23e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequest.java
@@ -34,16 +34,23 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.info.ClusterInfoRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * A request to retrieve information about an index.
+ *
+ * @opensearch.internal
  */
 public class GetIndexRequest extends ClusterInfoRequest<GetIndexRequest> {
+    /**
+     * The features to get.
+     *
+     * @opensearch.internal
+     */
     public enum Feature {
         ALIASES((byte) 0),
         MAPPINGS((byte) 1),
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequestBuilder.java
index 6f93614fe3487..3019191e5570e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.master.info.ClusterInfoRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder to get information about an index.
+ *
+ * @opensearch.internal
+ */
 public class GetIndexRequestBuilder extends ClusterInfoRequestBuilder<GetIndexRequest, GetIndexResponse, GetIndexRequestBuilder> {
 
     public GetIndexRequestBuilder(OpenSearchClient client, GetIndexAction action, String... indices) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexResponse.java
index 4465dc88fe87d..4c06a69c74104 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/GetIndexResponse.java
@@ -32,47 +32,50 @@
 
 package org.opensearch.action.admin.indices.get;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 /**
  * A response for a get index action.
+ *
+ * @opensearch.internal
  */
 public class GetIndexResponse extends ActionResponse implements ToXContentObject {
 
-    private ImmutableOpenMap<String, MappingMetadata> mappings = ImmutableOpenMap.of();
-    private ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.of();
-    private ImmutableOpenMap<String, Settings> settings = ImmutableOpenMap.of();
-    private ImmutableOpenMap<String, Settings> defaultSettings = ImmutableOpenMap.of();
-    private ImmutableOpenMap<String, String> dataStreams = ImmutableOpenMap.of();
+    private Map<String, MappingMetadata> mappings = Map.of();
+    private Map<String, List<AliasMetadata>> aliases = Map.of();
+    private Map<String, Settings> settings = Map.of();
+    private Map<String, Settings> defaultSettings = Map.of();
+    private Map<String, String> dataStreams = Map.of();
     private final String[] indices;
 
     public GetIndexResponse(
         String[] indices,
-        ImmutableOpenMap<String, MappingMetadata> mappings,
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases,
-        ImmutableOpenMap<String, Settings> settings,
-        ImmutableOpenMap<String, Settings> defaultSettings,
-        ImmutableOpenMap<String, String> dataStreams
+        Map<String, MappingMetadata> mappings,
+        final Map<String, List<AliasMetadata>> aliases,
+        final Map<String, Settings> settings,
+        final Map<String, Settings> defaultSettings,
+        final Map<String, String> dataStreams
     ) {
         this.indices = indices;
         // to have deterministic order
@@ -81,16 +84,16 @@ public GetIndexResponse(
             this.mappings = mappings;
         }
         if (aliases != null) {
-            this.aliases = aliases;
+            this.aliases = Collections.unmodifiableMap(aliases);
         }
         if (settings != null) {
-            this.settings = settings;
+            this.settings = Collections.unmodifiableMap(settings);
         }
         if (defaultSettings != null) {
-            this.defaultSettings = defaultSettings;
+            this.defaultSettings = Collections.unmodifiableMap(defaultSettings);
         }
         if (dataStreams != null) {
-            this.dataStreams = dataStreams;
+            this.dataStreams = Collections.unmodifiableMap(dataStreams);
         }
     }
 
@@ -99,7 +102,7 @@ public GetIndexResponse(
         this.indices = in.readStringArray();
 
         int mappingsSize = in.readVInt();
-        ImmutableOpenMap.Builder<String, MappingMetadata> mappingsMapBuilder = ImmutableOpenMap.builder();
+        Map<String, MappingMetadata> mappingsMapBuilder = new HashMap<>();
         for (int i = 0; i < mappingsSize; i++) {
             String index = in.readString();
             if (in.getVersion().before(Version.V_2_0_0)) {
@@ -120,10 +123,10 @@ public GetIndexResponse(
                 mappingsMapBuilder.put(index, metadata != null ? metadata : MappingMetadata.EMPTY_MAPPINGS);
             }
         }
-        mappings = mappingsMapBuilder.build();
+        mappings = Collections.unmodifiableMap(mappingsMapBuilder);
 
         int aliasesSize = in.readVInt();
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> aliasesMapBuilder = ImmutableOpenMap.builder();
+        final Map<String, List<AliasMetadata>> aliasesMapBuilder = new HashMap<>();
         for (int i = 0; i < aliasesSize; i++) {
             String key = in.readString();
             int valueSize = in.readVInt();
@@ -133,30 +136,30 @@ public GetIndexResponse(
             }
             aliasesMapBuilder.put(key, Collections.unmodifiableList(aliasEntryBuilder));
         }
-        aliases = aliasesMapBuilder.build();
+        aliases = Collections.unmodifiableMap(aliasesMapBuilder);
 
         int settingsSize = in.readVInt();
-        ImmutableOpenMap.Builder<String, Settings> settingsMapBuilder = ImmutableOpenMap.builder();
+        final Map<String, Settings> settingsMapBuilder = new HashMap<>();
         for (int i = 0; i < settingsSize; i++) {
             String key = in.readString();
             settingsMapBuilder.put(key, Settings.readSettingsFromStream(in));
         }
-        settings = settingsMapBuilder.build();
+        settings = Collections.unmodifiableMap(settingsMapBuilder);
 
-        ImmutableOpenMap.Builder<String, Settings> defaultSettingsMapBuilder = ImmutableOpenMap.builder();
+        final Map<String, Settings> defaultSettingsMapBuilder = new HashMap<>();
         int defaultSettingsSize = in.readVInt();
         for (int i = 0; i < defaultSettingsSize; i++) {
             defaultSettingsMapBuilder.put(in.readString(), Settings.readSettingsFromStream(in));
         }
-        defaultSettings = defaultSettingsMapBuilder.build();
+        defaultSettings = Collections.unmodifiableMap(defaultSettingsMapBuilder);
 
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_8_0)) {
-            ImmutableOpenMap.Builder<String, String> dataStreamsMapBuilder = ImmutableOpenMap.builder();
+            final Map<String, String> dataStreamsMapBuilder = new HashMap<>();
             int dataStreamsSize = in.readVInt();
             for (int i = 0; i < dataStreamsSize; i++) {
                 dataStreamsMapBuilder.put(in.readString(), in.readOptionalString());
             }
-            dataStreams = dataStreamsMapBuilder.build();
+            dataStreams = Collections.unmodifiableMap(dataStreamsMapBuilder);
         }
     }
 
@@ -168,31 +171,31 @@ public String[] getIndices() {
         return indices();
     }
 
-    public ImmutableOpenMap<String, MappingMetadata> mappings() {
+    public Map<String, MappingMetadata> mappings() {
         return mappings;
     }
 
-    public ImmutableOpenMap<String, MappingMetadata> getMappings() {
+    public Map<String, MappingMetadata> getMappings() {
         return mappings();
     }
 
-    public ImmutableOpenMap<String, List<AliasMetadata>> aliases() {
+    public Map<String, List<AliasMetadata>> aliases() {
         return aliases;
     }
 
-    public ImmutableOpenMap<String, List<AliasMetadata>> getAliases() {
+    public Map<String, List<AliasMetadata>> getAliases() {
         return aliases();
     }
 
-    public ImmutableOpenMap<String, Settings> settings() {
+    public Map<String, Settings> settings() {
         return settings;
     }
 
-    public ImmutableOpenMap<String, String> dataStreams() {
+    public Map<String, String> dataStreams() {
         return dataStreams;
     }
 
-    public ImmutableOpenMap<String, String> getDataStreams() {
+    public Map<String, String> getDataStreams() {
         return dataStreams();
     }
 
@@ -204,11 +207,11 @@ public ImmutableOpenMap<String, String> getDataStreams() {
      * via {@link #settings()}.
      * See also {@link GetIndexRequest#includeDefaults(boolean)}
      */
-    public ImmutableOpenMap<String, Settings> defaultSettings() {
+    public Map<String, Settings> defaultSettings() {
         return defaultSettings;
     }
 
-    public ImmutableOpenMap<String, Settings> getSettings() {
+    public Map<String, Settings> getSettings() {
         return settings();
     }
 
@@ -240,41 +243,41 @@ public String getSetting(String index, String setting) {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeStringArray(indices);
         out.writeVInt(mappings.size());
-        for (ObjectObjectCursor<String, MappingMetadata> indexEntry : mappings) {
-            out.writeString(indexEntry.key);
+        for (final Map.Entry<String, MappingMetadata> indexEntry : mappings.entrySet()) {
+            out.writeString(indexEntry.getKey());
             if (out.getVersion().before(Version.V_2_0_0)) {
-                out.writeVInt(indexEntry.value == MappingMetadata.EMPTY_MAPPINGS ? 0 : 1);
-                if (indexEntry.value != MappingMetadata.EMPTY_MAPPINGS) {
+                out.writeVInt(indexEntry.getValue() == MappingMetadata.EMPTY_MAPPINGS ? 0 : 1);
+                if (indexEntry.getValue() != MappingMetadata.EMPTY_MAPPINGS) {
                     out.writeString(MapperService.SINGLE_MAPPING_NAME);
-                    indexEntry.value.writeTo(out);
+                    indexEntry.getValue().writeTo(out);
                 }
             } else {
-                out.writeOptionalWriteable(indexEntry.value);
+                out.writeOptionalWriteable(indexEntry.getValue());
             }
         }
         out.writeVInt(aliases.size());
-        for (ObjectObjectCursor<String, List<AliasMetadata>> indexEntry : aliases) {
-            out.writeString(indexEntry.key);
-            out.writeVInt(indexEntry.value.size());
-            for (AliasMetadata aliasEntry : indexEntry.value) {
+        for (final Map.Entry<String, List<AliasMetadata>> indexEntry : aliases.entrySet()) {
+            out.writeString(indexEntry.getKey());
+            out.writeVInt(indexEntry.getValue().size());
+            for (AliasMetadata aliasEntry : indexEntry.getValue()) {
                 aliasEntry.writeTo(out);
             }
         }
         out.writeVInt(settings.size());
-        for (ObjectObjectCursor<String, Settings> indexEntry : settings) {
-            out.writeString(indexEntry.key);
-            Settings.writeSettingsToStream(indexEntry.value, out);
+        for (final Map.Entry<String, Settings> indexEntry : settings.entrySet()) {
+            out.writeString(indexEntry.getKey());
+            Settings.writeSettingsToStream(indexEntry.getValue(), out);
         }
         out.writeVInt(defaultSettings.size());
-        for (ObjectObjectCursor<String, Settings> indexEntry : defaultSettings) {
-            out.writeString(indexEntry.key);
-            Settings.writeSettingsToStream(indexEntry.value, out);
+        for (final Map.Entry<String, Settings> indexEntry : defaultSettings.entrySet()) {
+            out.writeString(indexEntry.getKey());
+            Settings.writeSettingsToStream(indexEntry.getValue(), out);
         }
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_8_0)) {
             out.writeVInt(dataStreams.size());
-            for (ObjectObjectCursor<String, String> indexEntry : dataStreams) {
-                out.writeString(indexEntry.key);
-                out.writeOptionalString(indexEntry.value);
+            for (final Map.Entry<String, String> indexEntry : dataStreams.entrySet()) {
+                out.writeString(indexEntry.getKey());
+                out.writeOptionalString(indexEntry.getValue());
             }
         }
     }
@@ -330,7 +333,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/TransportGetIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/get/TransportGetIndexAction.java
index 0cd3214307359..755119401c6b5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/get/TransportGetIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/TransportGetIndexAction.java
@@ -32,32 +32,36 @@
 
 package org.opensearch.action.admin.indices.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.info.TransportClusterInfoAction;
+import org.opensearch.action.support.clustermanager.info.TransportClusterInfoAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Spliterators;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 /**
  * Get index action.
+ *
+ * @opensearch.internal
  */
 public class TransportGetIndexAction extends TransportClusterInfoAction<GetIndexRequest, GetIndexResponse> {
 
@@ -96,22 +100,20 @@ protected GetIndexResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void doMasterOperation(
+    protected void doClusterManagerOperation(
         final GetIndexRequest request,
         String[] concreteIndices,
         final ClusterState state,
         final ActionListener<GetIndexResponse> listener
     ) {
-        ImmutableOpenMap<String, MappingMetadata> mappingsResult = ImmutableOpenMap.of();
-        ImmutableOpenMap<String, List<AliasMetadata>> aliasesResult = ImmutableOpenMap.of();
-        ImmutableOpenMap<String, Settings> settings = ImmutableOpenMap.of();
-        ImmutableOpenMap<String, Settings> defaultSettings = ImmutableOpenMap.of();
-        ImmutableOpenMap<String, String> dataStreams = ImmutableOpenMap.<String, String>builder()
-            .putAll(
-                StreamSupport.stream(state.metadata().findDataStreams(concreteIndices).spliterator(), false)
-                    .collect(Collectors.toMap(k -> k.key, v -> v.value.getName()))
-            )
-            .build();
+        Map<String, MappingMetadata> mappingsResult = Map.of();
+        Map<String, List<AliasMetadata>> aliasesResult = Map.of();
+        Map<String, Settings> settings = Map.of();
+        Map<String, Settings> defaultSettings = Map.of();
+        final Map<String, String> dataStreams = new HashMap<>(
+            StreamSupport.stream(Spliterators.spliterator(state.metadata().findDataStreams(concreteIndices).entrySet(), 0), false)
+                .collect(Collectors.toMap(k -> k.getKey(), v -> v.getValue().getName()))
+        );
         GetIndexRequest.Feature[] features = request.features();
         boolean doneAliases = false;
         boolean doneMappings = false;
@@ -130,15 +132,15 @@ protected void doMasterOperation(
                     }
                     break;
                 case ALIASES:
-                    if (!doneAliases) {
+                    if (doneAliases == false) {
                         aliasesResult = state.metadata().findAllAliases(concreteIndices);
                         doneAliases = true;
                     }
                     break;
                 case SETTINGS:
                     if (!doneSettings) {
-                        ImmutableOpenMap.Builder<String, Settings> settingsMapBuilder = ImmutableOpenMap.builder();
-                        ImmutableOpenMap.Builder<String, Settings> defaultSettingsMapBuilder = ImmutableOpenMap.builder();
+                        final Map<String, Settings> settingsMapBuilder = new HashMap<>();
+                        final Map<String, Settings> defaultSettingsMapBuilder = new HashMap<>();
                         for (String index : concreteIndices) {
                             Settings indexSettings = state.metadata().index(index).getSettings();
                             if (request.humanReadable()) {
@@ -152,8 +154,8 @@ protected void doMasterOperation(
                                 defaultSettingsMapBuilder.put(index, defaultIndexSettings);
                             }
                         }
-                        settings = settingsMapBuilder.build();
-                        defaultSettings = defaultSettingsMapBuilder.build();
+                        settings = settingsMapBuilder;
+                        defaultSettings = defaultSettingsMapBuilder;
                         doneSettings = true;
                     }
                     break;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/get/package-info.java
new file mode 100644
index 0000000000000..b438da7ef31dc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Index transport handler. */
+package org.opensearch.action.admin.indices.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsAction.java
index 320cfa622f11a..2ddd763be20fd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetFieldMappingsAction extends ActionType<GetFieldMappingsResponse> {
 
     public static final GetFieldMappingsAction INSTANCE = new GetFieldMappingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsIndexRequest.java
index 961662ecdcf7e..c82db7eca3fd9 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsIndexRequest.java
@@ -37,12 +37,17 @@
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport action to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetFieldMappingsIndexRequest extends SingleShardRequest<GetFieldMappingsIndexRequest> {
 
     private final boolean includeDefaults;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequest.java
index e6a2ad3187250..e3c812aedcfe7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequest.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -49,6 +49,8 @@
  *
  * Note: there is a new class with the same name for the Java HLRC that uses a typeless format.
  * Any changes done to this class should go to that client class as well.
+ *
+ * @opensearch.internal
  */
 public class GetFieldMappingsRequest extends ActionRequest implements IndicesRequest.Replaceable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequestBuilder.java
index 4a8c624e7e06e..ebc0c015c5140 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsRequestBuilder.java
@@ -37,7 +37,11 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
 
-/** A helper class to build {@link GetFieldMappingsRequest} objects */
+/**
+ * A helper class to build {@link GetFieldMappingsRequest} objects
+ *
+ * @opensearch.internal
+ **/
 public class GetFieldMappingsRequestBuilder extends ActionRequestBuilder<GetFieldMappingsRequest, GetFieldMappingsResponse> {
 
     public GetFieldMappingsRequestBuilder(OpenSearchClient client, GetFieldMappingsAction action, String... indices) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
index 12024ef455a32..d874b5bb6b1ac 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
@@ -33,19 +33,19 @@
 package org.opensearch.action.admin.indices.mapping.get;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MapperService;
 
@@ -56,14 +56,16 @@
 import java.util.Objects;
 
 import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Response object for {@link GetFieldMappingsRequest} API
  *
  * Note: there is a new class with the same name for the Java HLRC that uses a typeless format.
  * Any changes done to this class should go to that client class as well.
+ *
+ * @opensearch.internal
  */
 public class GetFieldMappingsResponse extends ActionResponse implements ToXContentObject {
 
@@ -173,6 +175,11 @@ private void addFieldMappingsToBuilder(XContentBuilder builder, Params params, M
         }
     }
 
+    /**
+     * Metadata for field mappings for toXContent
+     *
+     * @opensearch.internal
+     */
     public static class FieldMappingMetadata implements ToXContentFragment {
 
         private static final ParseField FULL_NAME = new ParseField("full_name");
@@ -207,7 +214,7 @@ public String fullName() {
 
         /** Returns the mappings as a map. Note that the returned map has a single key which is always the field's {@link Mapper#name}. */
         public Map<String, Object> sourceAsMap() {
-            return XContentHelper.convertToMap(source, true, XContentType.JSON).v2();
+            return XContentHelper.convertToMap(source, true, MediaTypeRegistry.JSON).v2();
         }
 
         // pkg-private for testing
@@ -226,7 +233,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                 builder.field("mapping", sourceAsMap());
             } else {
                 try (InputStream stream = source.streamInput()) {
-                    builder.rawField(MAPPING.getPreferredName(), stream, XContentType.JSON);
+                    builder.rawField(MAPPING.getPreferredName(), stream, MediaTypeRegistry.JSON);
                 }
             }
             return builder;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsAction.java
index 6d9ed5ba0411a..a78625a1595ad 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetMappingsAction extends ActionType<GetMappingsResponse> {
 
     public static final GetMappingsAction INSTANCE = new GetMappingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequest.java
index ae78f5f3a0b30..3988b0dd5a508 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequest.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.info.ClusterInfoRequest;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport request to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetMappingsRequest extends ClusterInfoRequest<GetMappingsRequest> {
 
     public GetMappingsRequest() {}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequestBuilder.java
index 8401272353eaf..85bf8c2ffd9c6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.master.info.ClusterInfoRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetMappingsRequestBuilder extends ClusterInfoRequestBuilder<
     GetMappingsRequest,
     GetMappingsResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponse.java
index 3be8e75be7290..e59f08c4fa162 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponse.java
@@ -32,35 +32,42 @@
 
 package org.opensearch.action.admin.indices.mapping.get;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
+/**
+ * Transport response to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class GetMappingsResponse extends ActionResponse implements ToXContentFragment {
 
     private static final ParseField MAPPINGS = new ParseField("mappings");
 
-    private final ImmutableOpenMap<String, MappingMetadata> mappings;
+    private final Map<String, MappingMetadata> mappings;
 
-    public GetMappingsResponse(ImmutableOpenMap<String, MappingMetadata> mappings) {
-        this.mappings = mappings;
+    public GetMappingsResponse(final Map<String, MappingMetadata> mappings) {
+        this.mappings = Collections.unmodifiableMap(mappings);
     }
 
     GetMappingsResponse(StreamInput in) throws IOException {
         super(in);
         int size = in.readVInt();
-        ImmutableOpenMap.Builder<String, MappingMetadata> indexMapBuilder = ImmutableOpenMap.builder();
+        final Map<String, MappingMetadata> indexMapBuilder = new HashMap<>();
         for (int i = 0; i < size; i++) {
             String index = in.readString();
             if (in.getVersion().before(Version.V_2_0_0)) {
@@ -81,40 +88,40 @@ public GetMappingsResponse(ImmutableOpenMap<String, MappingMetadata> mappings) {
                 indexMapBuilder.put(index, hasMapping ? new MappingMetadata(in) : MappingMetadata.EMPTY_MAPPINGS);
             }
         }
-        mappings = indexMapBuilder.build();
+        mappings = Collections.unmodifiableMap(indexMapBuilder);
     }
 
-    public ImmutableOpenMap<String, MappingMetadata> mappings() {
+    public Map<String, MappingMetadata> mappings() {
         return mappings;
     }
 
-    public ImmutableOpenMap<String, MappingMetadata> getMappings() {
+    public Map<String, MappingMetadata> getMappings() {
         return mappings();
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeVInt(mappings.size());
-        for (ObjectObjectCursor<String, MappingMetadata> indexEntry : mappings) {
-            out.writeString(indexEntry.key);
+        for (Map.Entry<String, MappingMetadata> indexEntry : mappings.entrySet()) {
+            out.writeString(indexEntry.getKey());
             if (out.getVersion().before(Version.V_2_0_0)) {
-                out.writeVInt(indexEntry.value == MappingMetadata.EMPTY_MAPPINGS ? 0 : 1);
-                if (indexEntry.value != MappingMetadata.EMPTY_MAPPINGS) {
+                out.writeVInt(indexEntry.getValue() == MappingMetadata.EMPTY_MAPPINGS ? 0 : 1);
+                if (indexEntry.getValue() != MappingMetadata.EMPTY_MAPPINGS) {
                     out.writeString(MapperService.SINGLE_MAPPING_NAME);
-                    indexEntry.value.writeTo(out);
+                    indexEntry.getValue().writeTo(out);
                 }
             } else {
-                out.writeOptionalWriteable(indexEntry.value);
+                out.writeOptionalWriteable(indexEntry.getValue());
             }
         }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        for (final ObjectObjectCursor<String, MappingMetadata> indexEntry : getMappings()) {
-            builder.startObject(indexEntry.key);
-            if (indexEntry.value != null) {
-                builder.field(MAPPINGS.getPreferredName(), indexEntry.value.sourceAsMap());
+        for (final Map.Entry<String, MappingMetadata> indexEntry : getMappings().entrySet()) {
+            builder.startObject(indexEntry.getKey());
+            if (indexEntry.getValue() != null) {
+                builder.field(MAPPINGS.getPreferredName(), indexEntry.getValue().sourceAsMap());
             } else {
                 builder.startObject(MAPPINGS.getPreferredName()).endObject();
             }
@@ -125,7 +132,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsAction.java
index bdb5222a6dcba..53dbb86233803 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsAction.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.action.admin.indices.mapping.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -50,6 +50,11 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Transport action to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class TransportGetFieldMappingsAction extends HandledTransportAction<GetFieldMappingsRequest, GetFieldMappingsResponse> {
 
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
index ca07475f0deab..368fef1446ba5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
@@ -43,18 +43,18 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.index.IndexService;
-import org.opensearch.index.mapper.MappingLookup;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.Mapper;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.mapper.MappingLookup;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -69,6 +69,8 @@
 
 /**
  * Transport action used to retrieve the mappings related to fields that belong to a specific index
+ *
+ * @opensearch.internal
  */
 public class TransportGetFieldMappingsIndexAction extends TransportSingleShardAction<
     GetFieldMappingsIndexRequest,
@@ -220,7 +222,7 @@ private static void addFieldMapper(
             try {
                 BytesReference bytes = XContentHelper.toXContent(
                     fieldMapper,
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     includeDefaults ? includeDefaultsParams : ToXContent.EMPTY_PARAMS,
                     false
                 );
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetMappingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetMappingsAction.java
index 3f6cb8ed35af9..6f07aa4dbf48a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetMappingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/TransportGetMappingsAction.java
@@ -34,22 +34,27 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.info.TransportClusterInfoAction;
+import org.opensearch.action.support.clustermanager.info.TransportClusterInfoAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.Map;
 
+/**
+ * Transport action to get field mappings.
+ *
+ * @opensearch.internal
+ */
 public class TransportGetMappingsAction extends TransportClusterInfoAction<GetMappingsRequest, GetMappingsResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportGetMappingsAction.class);
@@ -83,7 +88,7 @@ protected GetMappingsResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void doMasterOperation(
+    protected void doClusterManagerOperation(
         final GetMappingsRequest request,
         String[] concreteIndices,
         final ClusterState state,
@@ -91,8 +96,7 @@ protected void doMasterOperation(
     ) {
         logger.trace("serving getMapping request based on version {}", state.version());
         try {
-            ImmutableOpenMap<String, MappingMetadata> result = state.metadata()
-                .findMappings(concreteIndices, indicesService.getFieldFilter());
+            final Map<String, MappingMetadata> result = state.metadata().findMappings(concreteIndices, indicesService.getFieldFilter());
             listener.onResponse(new GetMappingsResponse(result));
         } catch (IOException e) {
             listener.onFailure(e);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/package-info.java
new file mode 100644
index 0000000000000..fcdd9846640bc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Mapping transport handlers. */
+package org.opensearch.action.admin.indices.mapping.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/AutoPutMappingAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/AutoPutMappingAction.java
index 72cfcdaffca31..f2430eb54db9b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/AutoPutMappingAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/AutoPutMappingAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action to automatically put field mappings.
+ *
+ * @opensearch.internal
+ */
 public class AutoPutMappingAction extends ActionType<AcknowledgedResponse> {
 
     public static final AutoPutMappingAction INSTANCE = new AutoPutMappingAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingAction.java
index 4f90e38ac4416..8bca1b59ee2e2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action to put field mappings.
+ *
+ * @opensearch.internal
+ */
 public class PutMappingAction extends ActionType<AcknowledgedResponse> {
 
     public static final PutMappingAction INSTANCE = new PutMappingAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingClusterStateUpdateRequest.java
index 27081048fcdae..8d51182d838cc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingClusterStateUpdateRequest.java
@@ -36,6 +36,8 @@
 
 /**
  * Cluster state update request that allows to put a mapping
+ *
+ * @opensearch.internal
  */
 public class PutMappingClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<PutMappingClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequest.java
index be3e676a4a1a2..1e780373e51df 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequest.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.indices.mapping.put;
 
-import com.carrotsearch.hppc.ObjectHashSet;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchGenerationException;
 import org.opensearch.Version;
@@ -41,18 +40,19 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -61,6 +61,7 @@
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
@@ -74,10 +75,12 @@
  * @see org.opensearch.client.Requests#putMappingRequest(String...)
  * @see org.opensearch.client.IndicesAdminClient#putMapping(PutMappingRequest)
  * @see AcknowledgedResponse
+ *
+ * @opensearch.internal
  */
 public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> implements IndicesRequest.Replaceable, ToXContentObject {
 
-    private static ObjectHashSet<String> RESERVED_FIELDS = ObjectHashSet.from(
+    private static final Set<String> RESERVED_FIELDS = Set.of(
         "_uid",
         "_id",
         "_type",
@@ -301,7 +304,7 @@ public PutMappingRequest source(XContentBuilder mappingBuilder) {
      */
     public PutMappingRequest source(Map<String, ?> mappingSource) {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             builder.map(mappingSource);
             return source(BytesReference.bytes(builder), builder.contentType());
         } catch (IOException e) {
@@ -312,17 +315,17 @@ public PutMappingRequest source(Map<String, ?> mappingSource) {
     /**
      * The mapping source definition.
      */
-    public PutMappingRequest source(String mappingSource, XContentType xContentType) {
-        return source(new BytesArray(mappingSource), xContentType);
+    public PutMappingRequest source(String mappingSource, MediaType mediaType) {
+        return source(new BytesArray(mappingSource), mediaType);
     }
 
     /**
      * The mapping source definition.
      */
-    public PutMappingRequest source(BytesReference mappingSource, XContentType xContentType) {
-        Objects.requireNonNull(xContentType);
+    public PutMappingRequest source(BytesReference mappingSource, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
         try {
-            this.source = XContentHelper.convertToJson(mappingSource, false, false, xContentType);
+            this.source = XContentHelper.convertToJson(mappingSource, false, false, mediaType);
             return this;
         } catch (IOException e) {
             throw new UncheckedIOException("failed to convert source to json", e);
@@ -361,7 +364,7 @@ public void writeTo(StreamOutput out) throws IOException {
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (source != null) {
             try (InputStream stream = new BytesArray(source).streamInput()) {
-                builder.rawValue(stream, XContentType.JSON);
+                builder.rawValue(stream, MediaTypeRegistry.JSON);
             }
         } else {
             builder.startObject().endObject();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
index 3ef96254b3f9b..9d703bf428c8e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
@@ -36,14 +36,16 @@
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.util.Map;
 
 /**
  * Builder for a put mapping request
+ *
+ * @opensearch.internal
  */
 public class PutMappingRequestBuilder extends AcknowledgedRequestBuilder<
     PutMappingRequest,
@@ -93,8 +95,8 @@ public PutMappingRequestBuilder setSource(Map mappingSource) {
     /**
      * The mapping source definition.
      */
-    public PutMappingRequestBuilder setSource(String mappingSource, XContentType xContentType) {
-        request.source(mappingSource, xContentType);
+    public PutMappingRequestBuilder setSource(String mappingSource, MediaType mediaType) {
+        request.source(mappingSource, mediaType);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportAutoPutMappingAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportAutoPutMappingAction.java
index a172fce831c8f..4722c1048014f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportAutoPutMappingAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportAutoPutMappingAction.java
@@ -31,10 +31,9 @@
 
 package org.opensearch.action.admin.indices.mapping.put;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -42,15 +41,21 @@
 import org.opensearch.cluster.metadata.MetadataMappingService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportAutoPutMappingAction extends TransportMasterNodeAction<PutMappingRequest, AcknowledgedResponse> {
+/**
+ * Transport action to automatically put field mappings.
+ *
+ * @opensearch.internal
+ */
+public class TransportAutoPutMappingAction extends TransportClusterManagerNodeAction<PutMappingRequest, AcknowledgedResponse> {
 
     private final MetadataMappingService metadataMappingService;
 
@@ -102,7 +107,7 @@ protected ClusterBlockException checkBlock(PutMappingRequest request, ClusterSta
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutMappingRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportPutMappingAction.java b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportPutMappingAction.java
index f1093a15a3d26..ac797914aafd8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportPutMappingAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/mapping/put/TransportPutMappingAction.java
@@ -35,11 +35,10 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RequestValidators;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -48,8 +47,9 @@
 import org.opensearch.cluster.metadata.MetadataMappingService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -63,8 +63,10 @@
 
 /**
  * Put mapping action.
+ *
+ * @opensearch.internal
  */
-public class TransportPutMappingAction extends TransportMasterNodeAction<PutMappingRequest, AcknowledgedResponse> {
+public class TransportPutMappingAction extends TransportClusterManagerNodeAction<PutMappingRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportPutMappingAction.class);
 
@@ -117,7 +119,7 @@ protected ClusterBlockException checkBlock(PutMappingRequest request, ClusterSta
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutMappingRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -169,7 +171,7 @@ static void performMappingUpdate(
     ) {
         PutMappingClusterStateUpdateRequest updateRequest = new PutMappingClusterStateUpdateRequest(request.source()).indices(
             concreteIndices
-        ).ackTimeout(request.timeout()).masterNodeTimeout(request.masterNodeTimeout());
+        ).ackTimeout(request.timeout()).masterNodeTimeout(request.clusterManagerNodeTimeout());
 
         metadataMappingService.putMapping(updateRequest, new ActionListener<ClusterStateUpdateResponse>() {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexAction.java
index 1b80e5cb8a347..5c4302d94e4a6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to open an index.
+ *
+ * @opensearch.internal
+ */
 public class OpenIndexAction extends ActionType<OpenIndexResponse> {
 
     public static final OpenIndexAction INSTANCE = new OpenIndexAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexClusterStateUpdateRequest.java
index bf299d103ba78..a36c2744f7669 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexClusterStateUpdateRequest.java
@@ -36,6 +36,8 @@
 
 /**
  * Cluster state update request that allows to open one or more indices
+ *
+ * @opensearch.internal
  */
 public class OpenIndexClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<OpenIndexClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequest.java
index be0e0254edff6..16451e311e7d3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequest.java
@@ -37,22 +37,26 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
+import java.util.Arrays;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
 /**
  * A request to open an index.
+ *
+ * @opensearch.internal
  */
 public class OpenIndexRequest extends AcknowledgedRequest<OpenIndexRequest> implements IndicesRequest.Replaceable {
 
     private String[] indices;
     private IndicesOptions indicesOptions = IndicesOptions.fromOptions(false, true, false, true);
     private ActiveShardCount waitForActiveShards = ActiveShardCount.DEFAULT;
+    private boolean shouldStoreResult;
 
     public OpenIndexRequest(StreamInput in) throws IOException {
         super(in);
@@ -159,6 +163,18 @@ public OpenIndexRequest waitForActiveShards(final int waitForActiveShards) {
         return waitForActiveShards(ActiveShardCount.from(waitForActiveShards));
     }
 
+    /**
+     * Should this task store its result after it has finished?
+     */
+    public void setShouldStoreResult(boolean shouldStoreResult) {
+        this.shouldStoreResult = shouldStoreResult;
+    }
+
+    @Override
+    public boolean getShouldStoreResult() {
+        return shouldStoreResult;
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
@@ -166,4 +182,14 @@ public void writeTo(StreamOutput out) throws IOException {
         indicesOptions.writeIndicesOptions(out);
         waitForActiveShards.writeTo(out);
     }
+
+    @Override
+    public String toString() {
+        return "open indices " + Arrays.toString(indices());
+    }
+
+    @Override
+    public String getDescription() {
+        return this.toString();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequestBuilder.java
index 5aadd81cc8838..bf09c3f173491 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexRequestBuilder.java
@@ -39,6 +39,8 @@
 
 /**
  * Builder for for open index request
+ *
+ * @opensearch.internal
  */
 public class OpenIndexRequestBuilder extends AcknowledgedRequestBuilder<OpenIndexRequest, OpenIndexResponse, OpenIndexRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexResponse.java
index 4b811b215d717..bd96a1071c129 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/OpenIndexResponse.java
@@ -33,15 +33,17 @@
 package org.opensearch.action.admin.indices.open;
 
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * A response for a open index action.
+ *
+ * @opensearch.internal
  */
 public class OpenIndexResponse extends ShardsAcknowledgedResponse {
 
@@ -72,4 +74,13 @@ public void writeTo(StreamOutput out) throws IOException {
     public static OpenIndexResponse fromXContent(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append(getClass().getSimpleName()).append("[");
+        builder.append("acknowledged=").append(isAcknowledged()).append(',');
+        builder.append("shards_acknowledged=").append(isShardsAcknowledged());
+        return builder.append(']').toString();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/TransportOpenIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/open/TransportOpenIndexAction.java
index 05b3bfd7a885e..0243990dce2ff 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/open/TransportOpenIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/TransportOpenIndexAction.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.DestructiveOperations;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.OpenIndexClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -47,8 +46,9 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -57,8 +57,10 @@
 
 /**
  * Open index action
+ *
+ * @opensearch.internal
  */
-public class TransportOpenIndexAction extends TransportMasterNodeAction<OpenIndexRequest, OpenIndexResponse> {
+public class TransportOpenIndexAction extends TransportClusterManagerNodeAction<OpenIndexRequest, OpenIndexResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportOpenIndexAction.class);
 
@@ -112,7 +114,7 @@ protected ClusterBlockException checkBlock(OpenIndexRequest request, ClusterStat
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final OpenIndexRequest request,
         final ClusterState state,
         final ActionListener<OpenIndexResponse> listener
@@ -123,7 +125,7 @@ protected void masterOperation(
             return;
         }
         OpenIndexClusterStateUpdateRequest updateRequest = new OpenIndexClusterStateUpdateRequest().ackTimeout(request.timeout())
-            .masterNodeTimeout(request.masterNodeTimeout())
+            .masterNodeTimeout(request.clusterManagerNodeTimeout())
             .indices(concreteIndices)
             .waitForActiveShards(request.waitForActiveShards());
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/open/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/open/package-info.java
new file mode 100644
index 0000000000000..4fdea8fd18769
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/open/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Open Index transport handlers. */
+package org.opensearch.action.admin.indices.open;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockAction.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockAction.java
index 482f543ae6b04..3bca633554908 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to add an index block.
+ *
+ * @opensearch.internal
+ */
 public class AddIndexBlockAction extends ActionType<AddIndexBlockResponse> {
 
     public static final AddIndexBlockAction INSTANCE = new AddIndexBlockAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockClusterStateUpdateRequest.java
index c934cad44b097..4b44624ece303 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockClusterStateUpdateRequest.java
@@ -36,6 +36,8 @@
 
 /**
  * Cluster state update request that allows to add a block to one or more indices
+ *
+ * @opensearch.internal
  */
 public class AddIndexBlockClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<AddIndexBlockClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequest.java
index c2f24d3e927b5..b5097f96fe52b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequest.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.cluster.metadata.IndexMetadata.APIBlock;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -48,6 +48,8 @@
 
 /**
  * A request to add a block to an index.
+ *
+ * @opensearch.internal
  */
 public class AddIndexBlockRequest extends AcknowledgedRequest<AddIndexBlockRequest> implements IndicesRequest.Replaceable {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequestBuilder.java
index 074e7fc5f6664..8322ba19f433e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockRequestBuilder.java
@@ -39,6 +39,8 @@
 
 /**
  * Builder for add index block request
+ *
+ * @opensearch.internal
  */
 public class AddIndexBlockRequestBuilder extends AcknowledgedRequestBuilder<
     AddIndexBlockRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockResponse.java
index 036a8ec635efc..13cee3f8e0159 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/AddIndexBlockResponse.java
@@ -32,17 +32,18 @@
 package org.opensearch.action.admin.indices.readonly;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -50,6 +51,11 @@
 
 import static java.util.Collections.unmodifiableList;
 
+/**
+ * Transport response to open an index.
+ *
+ * @opensearch.internal
+ */
 public class AddIndexBlockResponse extends ShardsAcknowledgedResponse {
 
     private final List<AddBlockResult> indices;
@@ -87,9 +93,14 @@ protected void addCustomFields(final XContentBuilder builder, final Params param
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * Result for adding a block
+     *
+     * @opensearch.internal
+     */
     public static class AddBlockResult implements Writeable, ToXContentFragment {
 
         private final Index index;
@@ -181,10 +192,15 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
     }
 
+    /**
+     * Per shard result for adding a block
+     *
+     * @opensearch.internal
+     */
     public static class AddBlockShardResult implements Writeable, ToXContentFragment {
 
         private final int id;
@@ -236,9 +252,14 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
+        /**
+         * Contains failure information
+         *
+         * @opensearch.internal
+         */
         public static class Failure extends DefaultShardOperationFailedException {
 
             private @Nullable String nodeId;
@@ -277,7 +298,7 @@ public XContentBuilder innerToXContent(final XContentBuilder builder, final Para
 
             @Override
             public String toString() {
-                return Strings.toString(this);
+                return Strings.toString(MediaTypeRegistry.JSON, this);
             }
 
             static Failure readFailure(final StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportAddIndexBlockAction.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportAddIndexBlockAction.java
index a58d199287ff7..eb018d16119e0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportAddIndexBlockAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportAddIndexBlockAction.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.DestructiveOperations;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -46,8 +45,9 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -62,8 +62,10 @@
  * in-flight writes to an index have been completed prior to the response being returned. These actions
  * are done in multiple cluster state updates (at least two). See also {@link TransportVerifyShardIndexBlockAction}
  * for the eventual delegation for shard-level verification.
+ *
+ * @opensearch.internal
  */
-public class TransportAddIndexBlockAction extends TransportMasterNodeAction<AddIndexBlockRequest, AddIndexBlockResponse> {
+public class TransportAddIndexBlockAction extends TransportClusterManagerNodeAction<AddIndexBlockRequest, AddIndexBlockResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportAddIndexBlockAction.class);
 
@@ -121,13 +123,13 @@ protected ClusterBlockException checkBlock(AddIndexBlockRequest request, Cluster
     }
 
     @Override
-    protected void masterOperation(AddIndexBlockRequest request, ClusterState state, ActionListener<AddIndexBlockResponse> listener)
+    protected void clusterManagerOperation(AddIndexBlockRequest request, ClusterState state, ActionListener<AddIndexBlockResponse> listener)
         throws Exception {
         throw new UnsupportedOperationException("The task parameter is required");
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final Task task,
         final AddIndexBlockRequest request,
         final ClusterState state,
@@ -142,7 +144,7 @@ protected void masterOperation(
         final AddIndexBlockClusterStateUpdateRequest addBlockRequest = new AddIndexBlockClusterStateUpdateRequest(
             request.getBlock(),
             task.getId()
-        ).ackTimeout(request.timeout()).masterNodeTimeout(request.masterNodeTimeout()).indices(concreteIndices);
+        ).ackTimeout(request.timeout()).masterNodeTimeout(request.clusterManagerNodeTimeout()).indices(concreteIndices);
         indexStateService.addIndexBlock(addBlockRequest, ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
             logger.debug(() -> new ParameterizedMessage("failed to mark indices as readonly [{}]", (Object) concreteIndices), t);
             delegatedListener.onFailure(t);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockAction.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockAction.java
index c96a94476c1fb..a86475a16a779 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockAction.java
@@ -33,7 +33,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ReplicationOperation;
@@ -45,14 +44,15 @@
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -64,6 +64,8 @@
  * and are no longer executing any operations in violation of that block. This action
  * requests all operation permits of the shard in order to wait for all write operations
  * to complete.
+ *
+ * @opensearch.internal
  */
 public class TransportVerifyShardIndexBlockAction extends TransportReplicationAction<
     TransportVerifyShardIndexBlockAction.ShardRequest,
@@ -168,6 +170,8 @@ protected ReplicationOperation.Replicas<ShardRequest> newReplicasProxy() {
      * A {@link ReplicasProxy} that marks as stale the shards that are unavailable during the verification
      * and the flush of the shard. This is done to ensure that such shards won't be later promoted as primary
      * or reopened in an unverified state with potential non flushed translog operations.
+     *
+     * @opensearch.internal
      */
     class VerifyShardReadOnlyActionReplicasProxy extends ReplicasProxy {
         @Override
@@ -181,6 +185,11 @@ public void markShardCopyAsStaleIfNeeded(
         }
     }
 
+    /**
+     * Per shard request
+     *
+     * @opensearch.internal
+     */
     public static class ShardRequest extends ReplicationRequest<ShardRequest> {
 
         private final ClusterBlock clusterBlock;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/readonly/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/readonly/package-info.java
new file mode 100644
index 0000000000000..d34d3c64eb1ad
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/readonly/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** ReadOnly Index transport handlers. */
+package org.opensearch.action.admin.indices.readonly;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryAction.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryAction.java
index ce764f8890f86..ac00e7f404b37 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Recovery information action
+ *
+ * @opensearch.internal
  */
 public class RecoveryAction extends ActionType<RecoveryResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequest.java
index 2457ca3fc5b90..69b20b697dd9a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequest.java
@@ -34,14 +34,16 @@
 
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Request for recovery information
+ *
+ * @opensearch.internal
  */
 public class RecoveryRequest extends BroadcastRequest<RecoveryRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequestBuilder.java
index 12c58c22fe8c8..99a1fb430fb28 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryRequestBuilder.java
@@ -37,6 +37,8 @@
 
 /**
  * Recovery information request builder.
+ *
+ * @opensearch.internal
  */
 public class RecoveryRequestBuilder extends BroadcastOperationRequestBuilder<RecoveryRequest, RecoveryResponse, RecoveryRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryResponse.java
index 9c2b380392b03..e6440fd95aa39 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/RecoveryResponse.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.action.admin.indices.recovery;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.indices.recovery.RecoveryState;
 
 import java.io.IOException;
@@ -46,6 +47,8 @@
 
 /**
  * Information regarding the recovery state of indices and their associated shards.
+ *
+ * @opensearch.internal
  */
 public class RecoveryResponse extends BroadcastResponse {
 
@@ -117,6 +120,6 @@ public void writeTo(StreamOutput out) throws IOException {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/TransportRecoveryAction.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/TransportRecoveryAction.java
index dd5ae31c01e56..de76ec2d4f5a7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/recovery/TransportRecoveryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/TransportRecoveryAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.admin.indices.recovery;
 
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -43,7 +42,8 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
@@ -60,6 +60,8 @@
 /**
  * Transport action for shard recovery operation. This transport action does not actually
  * perform shard recovery, it only reports on recoveries (both active and complete).
+ *
+ * @opensearch.internal
  */
 public class TransportRecoveryAction extends TransportBroadcastByNodeAction<RecoveryRequest, RecoveryResponse, RecoveryState> {
 
@@ -87,7 +89,7 @@ public TransportRecoveryAction(
 
     @Override
     protected RecoveryState readShardResult(StreamInput in) throws IOException {
-        return RecoveryState.readRecoveryState(in);
+        return new RecoveryState(in);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/recovery/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/recovery/package-info.java
new file mode 100644
index 0000000000000..51b7dd7997a15
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/recovery/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Recovery transport handlers. */
+package org.opensearch.action.admin.indices.recovery;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshAction.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshAction.java
index 6b7006c3b70ce..c321700ae65bd 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Refresh information action
+ *
+ * @opensearch.internal
+ */
 public class RefreshAction extends ActionType<RefreshResponse> {
 
     public static final RefreshAction INSTANCE = new RefreshAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequest.java
index c113527d1cc2f..c6e230cc66373 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequest.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.indices.refresh;
 
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
@@ -45,6 +45,8 @@
  * @see org.opensearch.client.Requests#refreshRequest(String...)
  * @see org.opensearch.client.IndicesAdminClient#refresh(RefreshRequest)
  * @see RefreshResponse
+ *
+ * @opensearch.internal
  */
 public class RefreshRequest extends BroadcastRequest<RefreshRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequestBuilder.java
index 47a16f2fc968d..5b27ae13f24be 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshRequestBuilder.java
@@ -39,6 +39,8 @@
  * A refresh request making all operations performed since the last refresh available for search. The (near) real-time
  * capabilities depends on the index engine used. For example, the internal one requires refresh to be called, but by
  * default a refresh is scheduled periodically.
+ *
+ * @opensearch.internal
  */
 public class RefreshRequestBuilder extends BroadcastOperationRequestBuilder<RefreshRequest, RefreshResponse, RefreshRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshResponse.java
index deae44b1c4676..4c89962dfec5e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/RefreshResponse.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.indices.refresh;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -44,6 +44,8 @@
 
 /**
  * The response of a refresh action.
+ *
+ * @opensearch.internal
  */
 public class RefreshResponse extends BroadcastResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportRefreshAction.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportRefreshAction.java
index 97e8344d32664..e276cbf900ff0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportRefreshAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportRefreshAction.java
@@ -34,20 +34,22 @@
 
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.replication.BasicReplicationRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.action.support.replication.TransportBroadcastReplicationAction;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.TransportService;
 
 import java.util.List;
 
 /**
  * Refresh action.
+ *
+ * @opensearch.internal
  */
 public class TransportRefreshAction extends TransportBroadcastReplicationAction<
     RefreshRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshAction.java b/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshAction.java
index c58d8c520ad0b..e17fa35395770 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.indices.refresh;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.BasicReplicationRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
@@ -40,8 +39,9 @@
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
@@ -49,6 +49,11 @@
 
 import java.io.IOException;
 
+/**
+ * Refresh information action
+ *
+ * @opensearch.internal
+ */
 public class TransportShardRefreshAction extends TransportReplicationAction<
     BasicReplicationRequest,
     BasicReplicationRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationShardStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationShardStatsResponse.java
new file mode 100644
index 0000000000000..ce17176a220ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationShardStatsResponse.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.indices.replication.SegmentReplicationState;
+
+import java.io.IOException;
+
+/**
+ * Segment Replication specific response object for fetching stats from either a primary
+ * or replica shard. The stats returned are different depending on primary or replica.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationShardStatsResponse implements Writeable {
+
+    @Nullable
+    private final SegmentReplicationPerGroupStats primaryStats;
+
+    @Nullable
+    private final SegmentReplicationState replicaStats;
+
+    public SegmentReplicationShardStatsResponse(StreamInput in) throws IOException {
+        this.primaryStats = in.readOptionalWriteable(SegmentReplicationPerGroupStats::new);
+        this.replicaStats = in.readOptionalWriteable(SegmentReplicationState::new);
+    }
+
+    public SegmentReplicationShardStatsResponse(SegmentReplicationPerGroupStats primaryStats) {
+        this.primaryStats = primaryStats;
+        this.replicaStats = null;
+    }
+
+    public SegmentReplicationShardStatsResponse(SegmentReplicationState replicaStats) {
+        this.replicaStats = replicaStats;
+        this.primaryStats = null;
+    }
+
+    public SegmentReplicationPerGroupStats getPrimaryStats() {
+        return primaryStats;
+    }
+
+    public SegmentReplicationState getReplicaStats() {
+        return replicaStats;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeOptionalWriteable(primaryStats);
+        out.writeOptionalWriteable(replicaStats);
+    }
+
+    @Override
+    public String toString() {
+        return "SegmentReplicationShardStatsResponse{" + "primaryStats=" + primaryStats + ", replicaStats=" + replicaStats + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsAction.java
new file mode 100644
index 0000000000000..9d1de20a8ff37
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Segment Replication stats information action
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStatsAction extends ActionType<SegmentReplicationStatsResponse> {
+    public static final SegmentReplicationStatsAction INSTANCE = new SegmentReplicationStatsAction();
+    public static final String NAME = "indices:monitor/segment_replication";
+
+    private SegmentReplicationStatsAction() {
+        super(NAME, SegmentReplicationStatsResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequest.java
new file mode 100644
index 0000000000000..c46940fbfecf9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequest.java
@@ -0,0 +1,114 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.broadcast.BroadcastRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Request for Segment Replication stats information
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStatsRequest extends BroadcastRequest<SegmentReplicationStatsRequest> {
+    private boolean detailed = false;       // Provides extra details in the response
+    private boolean activeOnly = false;     // Only reports on active segment replication events
+    private String[] shards = new String[0];
+
+    /**
+     * Constructs a request for segment replication stats information for all shards
+     */
+    public SegmentReplicationStatsRequest() {
+        this(Strings.EMPTY_ARRAY);
+    }
+
+    public SegmentReplicationStatsRequest(StreamInput in) throws IOException {
+        super(in);
+        detailed = in.readBoolean();
+        activeOnly = in.readBoolean();
+    }
+
+    /**
+     * Constructs a request for segment replication stats information for all shards for the given indices
+     *
+     * @param indices   Comma-separated list of indices about which to gather segment replication information
+     */
+    public SegmentReplicationStatsRequest(String... indices) {
+        super(indices, IndicesOptions.STRICT_EXPAND_OPEN_CLOSED);
+    }
+
+    /**
+     * True if detailed flag is set, false otherwise. This value if false by default.
+     *
+     * @return  True if detailed flag is set, false otherwise
+     */
+    public boolean detailed() {
+        return detailed;
+    }
+
+    /**
+     * Set value of the detailed flag. Detailed requests will contain extra
+     * information like timing metric of each stage of segment replication event.
+     *
+     * @param detailed  Whether or not to set the detailed flag
+     */
+    public void detailed(boolean detailed) {
+        this.detailed = detailed;
+    }
+
+    /**
+     * True if activeOnly flag is set, false otherwise. This value is false by default.
+     *
+     * @return  True if activeOnly flag is set, false otherwise
+     */
+    public boolean activeOnly() {
+        return activeOnly;
+    }
+
+    /**
+     * Set value of the activeOnly flag. If true, this request will only respond with
+     * on-going segment replication event information.
+     *
+     * @param activeOnly    Whether or not to set the activeOnly flag.
+     */
+    public void activeOnly(boolean activeOnly) {
+        this.activeOnly = activeOnly;
+    }
+
+    /**
+     * Contains list of shard id's if shards are passed, empty otherwise. Array is empty by default.
+     *
+     * @return  list of shard id's if shards are passed, empty otherwise
+     */
+    public String[] shards() {
+        return shards;
+    }
+
+    /**
+     * Set value of the shards. If shard id's are passed, this request will only respond with
+     * given specific shard's segment replication event information, instead of all shards.
+     *
+     * @param shards    contains list of shard id's.
+     */
+    public void shards(String[] shards) {
+        this.shards = shards;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeBoolean(detailed);
+        out.writeBoolean(activeOnly);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequestBuilder.java
new file mode 100644
index 0000000000000..7e68d2ac59f07
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsRequestBuilder.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+
+/**
+ * Segment Replication stats information request builder.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStatsRequestBuilder extends BroadcastOperationRequestBuilder<
+    SegmentReplicationStatsRequest,
+    SegmentReplicationStatsResponse,
+    SegmentReplicationStatsRequestBuilder> {
+
+    public SegmentReplicationStatsRequestBuilder(OpenSearchClient client, SegmentReplicationStatsAction action) {
+        super(client, action, new SegmentReplicationStatsRequest());
+    }
+
+    public SegmentReplicationStatsRequestBuilder setDetailed(boolean detailed) {
+        request.detailed(detailed);
+        return this;
+    }
+
+    public SegmentReplicationStatsRequestBuilder setActiveOnly(boolean activeOnly) {
+        request.activeOnly(activeOnly);
+        return this;
+    }
+
+    public SegmentReplicationStatsRequestBuilder shards(String... indices) {
+        request.shards(indices);
+        return this;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsResponse.java
new file mode 100644
index 0000000000000..f1b6b90e0cae1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsResponse.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.action.support.broadcast.BroadcastResponse;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Stats Information regarding the Segment Replication state of indices and their associated shards.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStatsResponse extends BroadcastResponse {
+    private final Map<String, List<SegmentReplicationPerGroupStats>> replicationStats;
+
+    public SegmentReplicationStatsResponse(StreamInput in) throws IOException {
+        super(in);
+        replicationStats = in.readMapOfLists(StreamInput::readString, SegmentReplicationPerGroupStats::new);
+    }
+
+    /**
+     * Constructs segment replication stats information for a collection of indices and associated shards. Keeps track of how many total shards
+     * were seen, and out of those how many were successfully processed and how many failed.
+     *
+     * @param totalShards             Total count of shards seen
+     * @param successfulShards        Count of shards successfully processed
+     * @param failedShards            Count of shards which failed to process
+     * @param replicationStats Map of indices to a list of {@link SegmentReplicationPerGroupStats}
+     * @param shardFailures           List of failures processing shards
+     */
+    public SegmentReplicationStatsResponse(
+        int totalShards,
+        int successfulShards,
+        int failedShards,
+        Map<String, List<SegmentReplicationPerGroupStats>> replicationStats,
+        List<DefaultShardOperationFailedException> shardFailures
+    ) {
+        super(totalShards, successfulShards, failedShards, shardFailures);
+        this.replicationStats = replicationStats;
+    }
+
+    public Map<String, List<SegmentReplicationPerGroupStats>> getReplicationStats() {
+        return replicationStats;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (replicationStats.size() > 0) {
+            for (String index : replicationStats.keySet()) {
+                List<SegmentReplicationPerGroupStats> segmentReplicationStates = replicationStats.get(index);
+                if (segmentReplicationStates == null || segmentReplicationStates.size() == 0) {
+                    continue;
+                }
+                builder.startObject(index);
+                builder.startArray("primary_stats");
+                for (SegmentReplicationPerGroupStats segmentReplicationState : segmentReplicationStates) {
+                    builder.startObject();
+                    segmentReplicationState.toXContent(builder, params);
+                    builder.endObject();
+                }
+                builder.endArray();
+                builder.endObject();
+            }
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeMapOfLists(replicationStats, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/TransportSegmentReplicationStatsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/TransportSegmentReplicationStatsAction.java
new file mode 100644
index 0000000000000..1b912518d7e04
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/TransportSegmentReplicationStatsAction.java
@@ -0,0 +1,184 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.replication;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardsIterator;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.index.SegmentReplicationPressureService;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Transport action for shard segment replication operation. This transport action does not actually
+ * perform segment replication, it only reports on metrics/stats of segment replication event (both active and complete).
+ *
+ * @opensearch.internal
+ */
+public class TransportSegmentReplicationStatsAction extends TransportBroadcastByNodeAction<
+    SegmentReplicationStatsRequest,
+    SegmentReplicationStatsResponse,
+    SegmentReplicationShardStatsResponse> {
+
+    private final SegmentReplicationTargetService targetService;
+    private final IndicesService indicesService;
+    private final SegmentReplicationPressureService pressureService;
+
+    @Inject
+    public TransportSegmentReplicationStatsAction(
+        ClusterService clusterService,
+        TransportService transportService,
+        IndicesService indicesService,
+        SegmentReplicationTargetService targetService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        SegmentReplicationPressureService pressureService
+    ) {
+        super(
+            SegmentReplicationStatsAction.NAME,
+            clusterService,
+            transportService,
+            actionFilters,
+            indexNameExpressionResolver,
+            SegmentReplicationStatsRequest::new,
+            ThreadPool.Names.MANAGEMENT
+        );
+        this.indicesService = indicesService;
+        this.targetService = targetService;
+        this.pressureService = pressureService;
+    }
+
+    @Override
+    protected SegmentReplicationShardStatsResponse readShardResult(StreamInput in) throws IOException {
+        return new SegmentReplicationShardStatsResponse(in);
+    }
+
+    @Override
+    protected SegmentReplicationStatsResponse newResponse(
+        SegmentReplicationStatsRequest request,
+        int totalShards,
+        int successfulShards,
+        int failedShards,
+        List<SegmentReplicationShardStatsResponse> responses,
+        List<DefaultShardOperationFailedException> shardFailures,
+        ClusterState clusterState
+    ) {
+        String[] shards = request.shards();
+        final List<Integer> shardsToFetch = Arrays.stream(shards).map(Integer::valueOf).collect(Collectors.toList());
+
+        // organize replica responses by allocationId.
+        final Map<String, SegmentReplicationState> replicaStats = new HashMap<>();
+        // map of index name to list of replication group stats.
+        final Map<String, List<SegmentReplicationPerGroupStats>> primaryStats = new HashMap<>();
+        for (SegmentReplicationShardStatsResponse response : responses) {
+            if (response != null) {
+                if (response.getReplicaStats() != null) {
+                    final ShardRouting shardRouting = response.getReplicaStats().getShardRouting();
+                    if (shardsToFetch.isEmpty() || shardsToFetch.contains(shardRouting.shardId().getId())) {
+                        replicaStats.putIfAbsent(shardRouting.allocationId().getId(), response.getReplicaStats());
+                    }
+                }
+                if (response.getPrimaryStats() != null) {
+                    final ShardId shardId = response.getPrimaryStats().getShardId();
+                    if (shardsToFetch.isEmpty() || shardsToFetch.contains(shardId.getId())) {
+                        primaryStats.compute(shardId.getIndexName(), (k, v) -> {
+                            if (v == null) {
+                                final ArrayList<SegmentReplicationPerGroupStats> list = new ArrayList<>();
+                                list.add(response.getPrimaryStats());
+                                return list;
+                            } else {
+                                v.add(response.getPrimaryStats());
+                                return v;
+                            }
+                        });
+                    }
+                }
+            }
+        }
+        // combine the replica stats to the shard stat entry in each group.
+        for (Map.Entry<String, List<SegmentReplicationPerGroupStats>> entry : primaryStats.entrySet()) {
+            for (SegmentReplicationPerGroupStats group : entry.getValue()) {
+                for (SegmentReplicationShardStats replicaStat : group.getReplicaStats()) {
+                    replicaStat.setCurrentReplicationState(replicaStats.getOrDefault(replicaStat.getAllocationId(), null));
+                }
+            }
+        }
+        return new SegmentReplicationStatsResponse(totalShards, successfulShards, failedShards, primaryStats, shardFailures);
+    }
+
+    @Override
+    protected SegmentReplicationStatsRequest readRequestFrom(StreamInput in) throws IOException {
+        return new SegmentReplicationStatsRequest(in);
+    }
+
+    @Override
+    protected SegmentReplicationShardStatsResponse shardOperation(SegmentReplicationStatsRequest request, ShardRouting shardRouting) {
+        IndexService indexService = indicesService.indexServiceSafe(shardRouting.shardId().getIndex());
+        IndexShard indexShard = indexService.getShard(shardRouting.shardId().id());
+        ShardId shardId = shardRouting.shardId();
+
+        if (indexShard.indexSettings().isSegRepEnabled() == false) {
+            return null;
+        }
+
+        if (shardRouting.primary()) {
+            return new SegmentReplicationShardStatsResponse(pressureService.getStatsForShard(indexShard));
+        }
+
+        // return information about only on-going segment replication events.
+        if (request.activeOnly()) {
+            return new SegmentReplicationShardStatsResponse(targetService.getOngoingEventSegmentReplicationState(shardId));
+        }
+        return new SegmentReplicationShardStatsResponse(targetService.getSegmentReplicationState(shardId));
+    }
+
+    @Override
+    protected ShardsIterator shards(ClusterState state, SegmentReplicationStatsRequest request, String[] concreteIndices) {
+        return state.routingTable().allShardsIncludingRelocationTargets(concreteIndices);
+    }
+
+    @Override
+    protected ClusterBlockException checkGlobalBlock(ClusterState state, SegmentReplicationStatsRequest request) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+
+    @Override
+    protected ClusterBlockException checkRequestBlock(
+        ClusterState state,
+        SegmentReplicationStatsRequest request,
+        String[] concreteIndices
+    ) {
+        return state.blocks().indicesBlockedException(ClusterBlockLevel.METADATA_READ, concreteIndices);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/replication/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/replication/package-info.java
new file mode 100644
index 0000000000000..db69c19825199
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/replication/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Segment Replication Stats transport handlers. */
+package org.opensearch.action.admin.indices.replication;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/resolve/ResolveIndexAction.java b/server/src/main/java/org/opensearch/action/admin/indices/resolve/ResolveIndexAction.java
index 8a9df3f59bc4c..98c2446e17998 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/resolve/ResolveIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/resolve/ResolveIndexAction.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.action.admin.indices.resolve;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.OriginalIndices;
@@ -51,15 +49,17 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterAware;
@@ -79,6 +79,11 @@
 import java.util.TreeMap;
 import java.util.stream.StreamSupport;
 
+/**
+ * Transport action to resolve an index.
+ *
+ * @opensearch.internal
+ */
 public class ResolveIndexAction extends ActionType<ResolveIndexAction.Response> {
 
     public static final ResolveIndexAction INSTANCE = new ResolveIndexAction();
@@ -88,6 +93,11 @@ private ResolveIndexAction() {
         super(NAME, Response::new);
     }
 
+    /**
+     * Request for resolving an index
+     *
+     * @opensearch.internal
+     */
     public static class Request extends ActionRequest implements IndicesRequest.Replaceable {
 
         public static final IndicesOptions DEFAULT_INDICES_OPTIONS = IndicesOptions.strictExpandOpen();
@@ -157,6 +167,11 @@ public boolean includeDataStreams() {
         }
     }
 
+    /**
+     * Abstraction class for resolving an index
+     *
+     * @opensearch.internal
+     */
     public static class ResolvedIndexAbstraction {
 
         static final ParseField NAME_FIELD = new ParseField("name");
@@ -178,6 +193,11 @@ public String getName() {
         }
     }
 
+    /**
+     * The resolved index
+     *
+     * @opensearch.internal
+     */
     public static class ResolvedIndex extends ResolvedIndexAbstraction implements Writeable, ToXContentObject {
 
         static final ParseField ALIASES_FIELD = new ParseField("aliases");
@@ -261,6 +281,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * The resolved index alias
+     *
+     * @opensearch.internal
+     */
     public static class ResolvedAlias extends ResolvedIndexAbstraction implements Writeable, ToXContentObject {
 
         static final ParseField INDICES_FIELD = new ParseField("indices");
@@ -318,6 +343,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * The resolved data stream
+     *
+     * @opensearch.internal
+     */
     public static class ResolvedDataStream extends ResolvedIndexAbstraction implements Writeable, ToXContentObject {
 
         static final ParseField BACKING_INDICES_FIELD = new ParseField("backing_indices");
@@ -385,6 +415,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * Response for resolving an index
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse implements ToXContentObject {
 
         static final ParseField INDICES_FIELD = new ParseField("indices");
@@ -450,6 +485,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * Transport action for resolving an index
+     *
+     * @opensearch.internal
+     */
     public static class TransportAction extends HandledTransportAction<Request, Response> {
 
         private final ThreadPool threadPool;
@@ -595,7 +635,7 @@ private static void enrichIndexAbstraction(
                         IndexAbstraction.Index index = (IndexAbstraction.Index) ia;
 
                         String[] aliasNames = StreamSupport.stream(
-                            Spliterators.spliteratorUnknownSize(index.getWriteIndex().getAliases().keysIt(), 0),
+                            Spliterators.spliteratorUnknownSize(index.getWriteIndex().getAliases().keySet().iterator(), 0),
                             false
                         ).toArray(String[]::new);
                         Arrays.sort(aliasNames);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/resolve/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/resolve/package-info.java
new file mode 100644
index 0000000000000..a7732563cb041
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/resolve/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Resolve transport handler. */
+package org.opensearch.action.admin.indices.resolve;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/Condition.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/Condition.java
index 7b2707ed16ca2..e014d6d703500 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/Condition.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/Condition.java
@@ -33,14 +33,16 @@
 package org.opensearch.action.admin.indices.rollover;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
 
 import java.util.Objects;
 
 /**
  * Base class for rollover request conditions
+ *
+ * @opensearch.internal
  */
 public abstract class Condition<T> implements NamedWriteable, ToXContentFragment {
 
@@ -93,6 +95,8 @@ public String name() {
 
     /**
      * Holder for index stats used to evaluate conditions
+     *
+     * @opensearch.internal
      */
     public static class Stats {
         public final long numDocs;
@@ -108,6 +112,8 @@ public Stats(long numDocs, long indexCreated, ByteSizeValue indexSize) {
 
     /**
      * Holder for evaluated condition result
+     *
+     * @opensearch.internal
      */
     public static class Result {
         public final Condition<?> condition;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxAgeCondition.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxAgeCondition.java
index 20c45d88c8d32..da750594e7264 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxAgeCondition.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxAgeCondition.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.action.admin.indices.rollover;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * Condition for index maximum age. Evaluates to <code>true</code>
  * when the index is at least {@link #value} old
+ *
+ * @opensearch.internal
  */
 public class MaxAgeCondition extends Condition<TimeValue> {
     public static final String NAME = "max_age";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxDocsCondition.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxDocsCondition.java
index 8491b381fd9d3..9c7684e25e543 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxDocsCondition.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxDocsCondition.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.action.admin.indices.rollover;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * Condition for maximum index docs. Evaluates to <code>true</code>
  * when the index has at least {@link #value} docs
+ *
+ * @opensearch.internal
  */
 public class MaxDocsCondition extends Condition<Long> {
     public static final String NAME = "max_docs";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxSizeCondition.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxSizeCondition.java
index 147d81a52961d..faa3558420a5c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxSizeCondition.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MaxSizeCondition.java
@@ -32,18 +32,20 @@
 
 package org.opensearch.action.admin.indices.rollover;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * A size-based condition for an index size.
  * Evaluates to <code>true</code> if the index size is at least {@link #value}.
+ *
+ * @opensearch.internal
  */
 public class MaxSizeCondition extends Condition<ByteSizeValue> {
     public static final String NAME = "max_size";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverService.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverService.java
index 19a7b8c95199b..c6193c076ee50 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverService.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverService.java
@@ -48,9 +48,9 @@
 import org.opensearch.cluster.metadata.MetadataIndexAliasesService;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.Arrays;
@@ -69,10 +69,12 @@
 
 /**
  * Service responsible for handling rollover requests for write aliases and data streams
+ *
+ * @opensearch.internal
  */
 public class MetadataRolloverService {
     private static final Pattern INDEX_NAME_PATTERN = Pattern.compile("^.*-\\d+$");
-    private static final List<IndexAbstraction.Type> VALID_ROLLOVER_TARGETS = org.opensearch.common.collect.List.of(ALIAS, DATA_STREAM);
+    private static final List<IndexAbstraction.Type> VALID_ROLLOVER_TARGETS = List.of(ALIAS, DATA_STREAM);
 
     private final ThreadPool threadPool;
     private final MetadataCreateIndexService createIndexService;
@@ -92,6 +94,11 @@ public MetadataRolloverService(
         this.indexNameExpressionResolver = indexNameExpressionResolver;
     }
 
+    /**
+     * Result for rollover request
+     *
+     * @opensearch.internal
+     */
     public static class RolloverResult {
         public final String rolloverIndexName;
         public final String sourceIndexName;
@@ -181,7 +188,7 @@ private RolloverResult rolloverAlias(
         ClusterState newState = createIndexService.applyCreateIndexRequest(currentState, createIndexClusterStateRequest, silent);
         newState = indexAliasesService.applyAliasActions(
             newState,
-            rolloverAliasToNewIndex(sourceIndexName, rolloverIndexName, explicitWriteIndex, aliasMetadata.isHidden(), aliasName)
+            rolloverAliasToNewIndex(sourceIndexName, rolloverIndexName, explicitWriteIndex, aliasMetadata, aliasName)
         );
 
         RolloverInfo rolloverInfo = new RolloverInfo(aliasName, metConditions, threadPool.absoluteTimeInMillis());
@@ -286,7 +293,7 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
             b.put(settings);
         }
         return new CreateIndexClusterStateUpdateRequest(cause, targetIndexName, providedIndexName).ackTimeout(createIndexRequest.timeout())
-            .masterNodeTimeout(createIndexRequest.masterNodeTimeout())
+            .masterNodeTimeout(createIndexRequest.clusterManagerNodeTimeout())
             .settings(b.build())
             .aliases(createIndexRequest.aliases())
             .waitForActiveShards(ActiveShardCount.NONE) // not waiting for shards here, will wait on the alias switch operation
@@ -302,20 +309,46 @@ static List<AliasAction> rolloverAliasToNewIndex(
         String oldIndex,
         String newIndex,
         boolean explicitWriteIndex,
-        @Nullable Boolean isHidden,
+        AliasMetadata aliasMetadata,
         String alias
     ) {
+        String filterAsString = aliasMetadata.getFilter() != null ? aliasMetadata.getFilter().string() : null;
+
         if (explicitWriteIndex) {
             return Collections.unmodifiableList(
                 Arrays.asList(
-                    new AliasAction.Add(newIndex, alias, null, null, null, true, isHidden),
-                    new AliasAction.Add(oldIndex, alias, null, null, null, false, isHidden)
+                    new AliasAction.Add(
+                        newIndex,
+                        alias,
+                        filterAsString,
+                        aliasMetadata.getIndexRouting(),
+                        aliasMetadata.getSearchRouting(),
+                        true,
+                        aliasMetadata.isHidden()
+                    ),
+                    new AliasAction.Add(
+                        oldIndex,
+                        alias,
+                        filterAsString,
+                        aliasMetadata.getIndexRouting(),
+                        aliasMetadata.getSearchRouting(),
+                        false,
+                        aliasMetadata.isHidden()
+                    )
                 )
             );
         } else {
             return Collections.unmodifiableList(
                 Arrays.asList(
-                    new AliasAction.Add(newIndex, alias, null, null, null, null, isHidden),
+                    new AliasAction.Add(
+                        newIndex,
+                        alias,
+                        filterAsString,
+                        aliasMetadata.getIndexRouting(),
+                        aliasMetadata.getSearchRouting(),
+                        null,
+                        aliasMetadata.isHidden()
+                    ),
                     new AliasAction.Remove(oldIndex, alias, null)
                 )
             );
@@ -341,7 +374,7 @@ static void checkNoDuplicatedAliasInIndexTemplate(
                         Locale.ROOT,
                         "Rollover alias [%s] can point to multiple indices, found duplicated alias [%s] in index template [%s]",
                         rolloverRequestAlias,
-                        template.aliases().keys(),
+                        template.aliases().keySet(),
                         template.name()
                     )
                 );
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverAction.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverAction.java
index f95cf1b83250a..e6c22cc48c1ad 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to rollover an index.
+ *
+ * @opensearch.internal
+ */
 public class RolloverAction extends ActionType<RolloverResponse> {
 
     public static final RolloverAction INSTANCE = new RolloverAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverInfo.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverInfo.java
index 3fd145a7c7655..475e44e1820d5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverInfo.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverInfo.java
@@ -34,15 +34,16 @@
 
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
@@ -50,6 +51,8 @@
 
 /**
  * Class for holding Rollover related information within an index
+ *
+ * @opensearch.internal
  */
 public class RolloverInfo extends AbstractDiffable<RolloverInfo> implements Writeable, ToXContentFragment {
 
@@ -146,6 +149,6 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequest.java
index 402b3741205a2..b25bc94a5c8e2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequest.java
@@ -37,13 +37,13 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -57,6 +57,8 @@
  *
  * Note: there is a new class with the same name for the Java HLRC that uses a typeless format.
  * Any changes done to this class should also go to that client class.
+ *
+ * @opensearch.internal
  */
 public class RolloverRequest extends AcknowledgedRequest<RolloverRequest> implements IndicesRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequestBuilder.java
index c74f71a70e09d..9e6b8518e92d3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverRequestBuilder.java
@@ -33,13 +33,21 @@
 
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.support.ActiveShardCount;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
-public class RolloverRequestBuilder extends MasterNodeOperationRequestBuilder<RolloverRequest, RolloverResponse, RolloverRequestBuilder> {
+/**
+ * Transport request to rollover an index.
+ *
+ * @opensearch.internal
+ */
+public class RolloverRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
+    RolloverRequest,
+    RolloverResponse,
+    RolloverRequestBuilder> {
     public RolloverRequestBuilder(OpenSearchClient client, RolloverAction action) {
         super(client, action, new RolloverRequest());
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverResponse.java
index 5600d05120abb..55ee65d0a4973 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/RolloverResponse.java
@@ -33,27 +33,29 @@
 package org.opensearch.action.admin.indices.rollover;
 
 import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Response object for {@link RolloverRequest} API
  *
  * Note: there is a new class with the same name for the Java HLRC that uses a typeless format.
  * Any changes done to this class should also go to that client class.
+ *
+ * @opensearch.internal
  */
 public final class RolloverResponse extends ShardsAcknowledgedResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/TransportRolloverAction.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/TransportRolloverAction.java
index 38f25422a5956..3b11a3d82d707 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/rollover/TransportRolloverAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/TransportRolloverAction.java
@@ -33,14 +33,13 @@
 package org.opensearch.action.admin.indices.rollover;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.stats.IndicesStatsAction;
 import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardsObserver;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
@@ -49,11 +48,14 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.shard.DocsStats;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -69,12 +71,15 @@
 
 /**
  * Main class to swap the index pointed to by an alias, given some conditions
+ *
+ * @opensearch.internal
  */
-public class TransportRolloverAction extends TransportMasterNodeAction<RolloverRequest, RolloverResponse> {
+public class TransportRolloverAction extends TransportClusterManagerNodeAction<RolloverRequest, RolloverResponse> {
 
     private final MetadataRolloverService rolloverService;
     private final ActiveShardsObserver activeShardsObserver;
     private final Client client;
+    private final ClusterManagerTaskThrottler.ThrottlingKey rolloverIndexTaskKey;
 
     @Inject
     public TransportRolloverAction(
@@ -98,6 +103,8 @@ public TransportRolloverAction(
         this.rolloverService = rolloverService;
         this.client = client;
         this.activeShardsObserver = new ActiveShardsObserver(clusterService, threadPool);
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        rolloverIndexTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.ROLLOVER_INDEX_KEY, true);
     }
 
     @Override
@@ -128,13 +135,13 @@ protected ClusterBlockException checkBlock(RolloverRequest request, ClusterState
     }
 
     @Override
-    protected void masterOperation(RolloverRequest request, ClusterState state, ActionListener<RolloverResponse> listener)
+    protected void clusterManagerOperation(RolloverRequest request, ClusterState state, ActionListener<RolloverResponse> listener)
         throws Exception {
         throw new UnsupportedOperationException("The task parameter is required");
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         Task task,
         final RolloverRequest rolloverRequest,
         final ClusterState state,
@@ -202,6 +209,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                                 return rolloverResult.clusterState;
                             }
 
+                            @Override
+                            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                                return rolloverIndexTaskKey;
+                            }
+
                             @Override
                             public void onFailure(String source, Exception e) {
                                 listener.onFailure(e);
@@ -213,7 +225,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                                     activeShardsObserver.waitForActiveShards(
                                         new String[] { rolloverIndexName },
                                         rolloverRequest.getCreateIndexRequest().waitForActiveShards(),
-                                        rolloverRequest.masterNodeTimeout(),
+                                        rolloverRequest.clusterManagerNodeTimeout(),
                                         isShardsAcknowledged -> listener.onResponse(
                                             new RolloverResponse(
                                                 sourceIndexName,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/rollover/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/rollover/package-info.java
new file mode 100644
index 0000000000000..23b5b18e3ae87
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/rollover/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Rollover transport handlers. */
+package org.opensearch.action.admin.indices.rollover;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexSegments.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexSegments.java
index 907f352a5ed89..88973ce094d8b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexSegments.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexSegments.java
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * List of Index Segments
+ *
+ * @opensearch.internal
+ */
 public class IndexSegments implements Iterable<IndexShardSegments> {
 
     private final String index;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexShardSegments.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexShardSegments.java
index 470480c2ac064..a6caf0649fde1 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexShardSegments.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndexShardSegments.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.admin.indices.segments;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Arrays;
 import java.util.Iterator;
 
+/**
+ * List of Index Shard Segments
+ *
+ * @opensearch.internal
+ */
 public class IndexShardSegments implements Iterable<ShardSegments> {
 
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponse.java
index 82fe438236d0f..64c98fa999d08 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponse.java
@@ -36,18 +36,15 @@
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSortField;
-import org.apache.lucene.util.Accountable;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.Segment;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -55,6 +52,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Transport response for retrieving indices segment information
+ *
+ * @opensearch.internal
+ */
 public class IndicesSegmentResponse extends BroadcastResponse {
 
     private final ShardSegments[] shards;
@@ -192,21 +194,11 @@ private static void toXContent(XContentBuilder builder, Sort sort) throws IOExce
         builder.endArray();
     }
 
-    private static void toXContent(XContentBuilder builder, Accountable tree) throws IOException {
-        builder.startObject();
-        builder.field(Fields.DESCRIPTION, tree.toString());
-        builder.humanReadableField(Fields.SIZE_IN_BYTES, Fields.SIZE, new ByteSizeValue(tree.ramBytesUsed()));
-        Collection<Accountable> children = tree.getChildResources();
-        if (children.isEmpty() == false) {
-            builder.startArray(Fields.CHILDREN);
-            for (Accountable child : children) {
-                toXContent(builder, child);
-            }
-            builder.endArray();
-        }
-        builder.endObject();
-    }
-
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String INDICES = "indices";
         static final String SHARDS = "shards";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsAction.java
index 467de4590e746..54a10ce259190 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for retrieving indices segment information
+ *
+ * @opensearch.internal
+ */
 public class IndicesSegmentsAction extends ActionType<IndicesSegmentResponse> {
 
     public static final IndicesSegmentsAction INSTANCE = new IndicesSegmentsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequest.java
index 14f6999692731..03a41cd21572f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequest.java
@@ -33,12 +33,17 @@
 package org.opensearch.action.admin.indices.segments;
 
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for retrieving indices segment information
+ *
+ * @opensearch.internal
+ */
 public class IndicesSegmentsRequest extends BroadcastRequest<IndicesSegmentsRequest> {
 
     protected boolean verbose = false;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestBuilder.java
index 4352344114f85..4b758e1f4bfb1 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for retrieving indices segment information
+ *
+ * @opensearch.internal
+ */
 public class IndicesSegmentsRequestBuilder extends BroadcastOperationRequestBuilder<
     IndicesSegmentsRequest,
     IndicesSegmentResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsAction.java
new file mode 100644
index 0000000000000..b52ef32a91b16
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsAction.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.segments;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action for retrieving segment information for PITs
+ */
+public class PitSegmentsAction extends ActionType<IndicesSegmentResponse> {
+
+    public static final PitSegmentsAction INSTANCE = new PitSegmentsAction();
+    public static final String NAME = "indices:monitor/point_in_time/segments";
+
+    private PitSegmentsAction() {
+        super(NAME, IndicesSegmentResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsRequest.java
new file mode 100644
index 0000000000000..aec624ed09b83
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/PitSegmentsRequest.java
@@ -0,0 +1,121 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.segments;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.broadcast.BroadcastRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Transport request for retrieving PITs segment information
+ */
+public class PitSegmentsRequest extends BroadcastRequest<PitSegmentsRequest> {
+    private boolean verbose = false;
+    private final List<String> pitIds = new ArrayList<>();
+
+    public PitSegmentsRequest() {
+        this(Strings.EMPTY_ARRAY);
+    }
+
+    public PitSegmentsRequest(StreamInput in) throws IOException {
+        super(in);
+        pitIds.addAll(Arrays.asList(in.readStringArray()));
+        verbose = in.readBoolean();
+    }
+
+    public PitSegmentsRequest(String... pitIds) {
+        super(pitIds);
+        this.pitIds.addAll(Arrays.asList(pitIds));
+    }
+
+    /**
+     * <code>true</code> if detailed information about each segment should be returned,
+     * <code>false</code> otherwise.
+     */
+    public boolean isVerbose() {
+        return verbose;
+    }
+
+    /**
+     * Sets the <code>verbose</code> option.
+     * @see #isVerbose()
+     */
+    public void setVerbose(boolean v) {
+        verbose = v;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArrayNullable((pitIds == null) ? null : pitIds.toArray(new String[pitIds.size()]));
+        out.writeBoolean(verbose);
+    }
+
+    public List<String> getPitIds() {
+        return Collections.unmodifiableList(pitIds);
+    }
+
+    public void clearAndSetPitIds(List<String> pitIds) {
+        this.pitIds.clear();
+        this.pitIds.addAll(pitIds);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (pitIds == null || pitIds.isEmpty()) {
+            validationException = addValidationError("no pit ids specified", validationException);
+        }
+        return validationException;
+    }
+
+    public void fromXContent(XContentParser parser) throws IOException {
+        pitIds.clear();
+        if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+            throw new IllegalArgumentException("Malformed content, must start with an object");
+        } else {
+            XContentParser.Token token;
+            String currentFieldName = null;
+            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    currentFieldName = parser.currentName();
+                } else if ("pit_id".equals(currentFieldName)) {
+                    if (token == XContentParser.Token.START_ARRAY) {
+                        while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                            if (token.isValue() == false) {
+                                throw new IllegalArgumentException("pit_id array element should only contain PIT identifier");
+                            }
+                            pitIds.add(parser.text());
+                        }
+                    } else {
+                        if (token.isValue() == false) {
+                            throw new IllegalArgumentException("pit_id element should only contain PIT identifier");
+                        }
+                        pitIds.add(parser.text());
+                    }
+                } else {
+                    throw new IllegalArgumentException(
+                        "Unknown parameter [" + currentFieldName + "] in request body or parameter is of the wrong type[" + token + "] "
+                    );
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/ShardSegments.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/ShardSegments.java
index a6e34d1d55823..90317542244ff 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/ShardSegments.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/ShardSegments.java
@@ -33,15 +33,20 @@
 package org.opensearch.action.admin.indices.segments;
 
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.engine.Segment;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Collection of shard segments
+ *
+ * @opensearch.internal
+ */
 public class ShardSegments implements Writeable, Iterable<Segment> {
 
     private final ShardRouting shardRouting;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportIndicesSegmentsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportIndicesSegmentsAction.java
index 7ff7bb3591f1d..9ec305b30e2b0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportIndicesSegmentsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportIndicesSegmentsAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.admin.indices.segments;
 
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -43,7 +42,8 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
@@ -53,6 +53,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport response for retrieving indices segment information
+ *
+ * @opensearch.internal
+ */
 public class TransportIndicesSegmentsAction extends TransportBroadcastByNodeAction<
     IndicesSegmentsRequest,
     IndicesSegmentResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportPitSegmentsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportPitSegmentsAction.java
new file mode 100644
index 0000000000000..805073f79645a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/TransportPitSegmentsAction.java
@@ -0,0 +1,264 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.action.admin.indices.segments;
+
+import org.opensearch.action.search.ListPitInfo;
+import org.opensearch.action.search.PitService;
+import org.opensearch.action.search.SearchContextId;
+import org.opensearch.action.search.SearchContextIdForNode;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.AllocationId;
+import org.opensearch.cluster.routing.PlainShardsIterator;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.ShardsIterator;
+import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.search.SearchService;
+import org.opensearch.search.internal.PitReaderContext;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.opensearch.action.search.SearchContextId.decode;
+
+/**
+ * Transport action for retrieving segment information of PITs
+ */
+public class TransportPitSegmentsAction extends TransportBroadcastByNodeAction<PitSegmentsRequest, IndicesSegmentResponse, ShardSegments> {
+    private final ClusterService clusterService;
+    private final IndicesService indicesService;
+    private final SearchService searchService;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final TransportService transportService;
+    private final PitService pitService;
+
+    @Inject
+    public TransportPitSegmentsAction(
+        ClusterService clusterService,
+        TransportService transportService,
+        IndicesService indicesService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        SearchService searchService,
+        NamedWriteableRegistry namedWriteableRegistry,
+        PitService pitService
+    ) {
+        super(
+            PitSegmentsAction.NAME,
+            clusterService,
+            transportService,
+            actionFilters,
+            indexNameExpressionResolver,
+            PitSegmentsRequest::new,
+            ThreadPool.Names.MANAGEMENT
+        );
+        this.clusterService = clusterService;
+        this.indicesService = indicesService;
+        this.searchService = searchService;
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        this.transportService = transportService;
+        this.pitService = pitService;
+    }
+
+    /**
+     * Execute PIT segments flow for all PITs or request PIT IDs
+     */
+    @Override
+    protected void doExecute(Task task, PitSegmentsRequest request, ActionListener<IndicesSegmentResponse> listener) {
+        if (request.getPitIds().size() == 1 && "_all".equals(request.getPitIds().get(0))) {
+            pitService.getAllPits(ActionListener.wrap(response -> {
+                request.clearAndSetPitIds(response.getPitInfos().stream().map(ListPitInfo::getPitId).collect(Collectors.toList()));
+                super.doExecute(task, request, listener);
+            }, listener::onFailure));
+        } else {
+            super.doExecute(task, request, listener);
+        }
+    }
+
+    /**
+     * This adds list of shards on which we need to retrieve pit segments details
+     * @param clusterState    the cluster state
+     * @param request         the underlying request
+     * @param concreteIndices the concrete indices on which to execute the operation
+     */
+    @Override
+    protected ShardsIterator shards(ClusterState clusterState, PitSegmentsRequest request, String[] concreteIndices) {
+        final ArrayList<ShardRouting> iterators = new ArrayList<>();
+        // remove duplicates from the request
+        Set<String> uniquePitIds = new LinkedHashSet<>(request.getPitIds());
+        for (String pitId : uniquePitIds) {
+            SearchContextId searchContext = decode(namedWriteableRegistry, pitId);
+            for (Map.Entry<ShardId, SearchContextIdForNode> entry : searchContext.shards().entrySet()) {
+                final SearchContextIdForNode perNode = entry.getValue();
+                // check if node is part of local cluster
+                if (Strings.isEmpty(perNode.getClusterAlias())) {
+                    final ShardId shardId = entry.getKey();
+                    iterators.add(
+                        new PitAwareShardRouting(
+                            pitId,
+                            shardId,
+                            perNode.getNode(),
+                            null,
+                            true,
+                            ShardRoutingState.STARTED,
+                            null,
+                            null,
+                            null,
+                            -1L
+                        )
+                    );
+                }
+            }
+        }
+        return new PlainShardsIterator(iterators);
+    }
+
+    @Override
+    protected ClusterBlockException checkGlobalBlock(ClusterState state, PitSegmentsRequest request) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+
+    @Override
+    protected ClusterBlockException checkRequestBlock(ClusterState state, PitSegmentsRequest countRequest, String[] concreteIndices) {
+        return state.blocks().indicesBlockedException(ClusterBlockLevel.METADATA_READ, concreteIndices);
+    }
+
+    @Override
+    protected ShardSegments readShardResult(StreamInput in) throws IOException {
+        return new ShardSegments(in);
+    }
+
+    @Override
+    protected IndicesSegmentResponse newResponse(
+        PitSegmentsRequest request,
+        int totalShards,
+        int successfulShards,
+        int failedShards,
+        List<ShardSegments> results,
+        List<DefaultShardOperationFailedException> shardFailures,
+        ClusterState clusterState
+    ) {
+        return new IndicesSegmentResponse(
+            results.toArray(new ShardSegments[results.size()]),
+            totalShards,
+            successfulShards,
+            failedShards,
+            shardFailures
+        );
+    }
+
+    @Override
+    protected PitSegmentsRequest readRequestFrom(StreamInput in) throws IOException {
+        return new PitSegmentsRequest(in);
+    }
+
+    @Override
+    public List<ShardRouting> getShardRoutingsFromInputStream(StreamInput in) throws IOException {
+        return in.readList(PitAwareShardRouting::new);
+    }
+
+    /**
+     * This retrieves segment details of PIT context
+     * @param request      the node-level request
+     * @param shardRouting the shard on which to execute the operation
+     */
+    @Override
+    protected ShardSegments shardOperation(PitSegmentsRequest request, ShardRouting shardRouting) {
+        assert shardRouting instanceof PitAwareShardRouting;
+        PitAwareShardRouting pitAwareShardRouting = (PitAwareShardRouting) shardRouting;
+        SearchContextIdForNode searchContextIdForNode = decode(namedWriteableRegistry, pitAwareShardRouting.getPitId()).shards()
+            .get(shardRouting.shardId());
+        PitReaderContext pitReaderContext = searchService.getPitReaderContext(searchContextIdForNode.getSearchContextId());
+        if (pitReaderContext == null) {
+            return new ShardSegments(shardRouting, Collections.emptyList());
+        }
+        return new ShardSegments(pitReaderContext.getShardRouting(), pitReaderContext.getSegments());
+    }
+
+    /**
+     * This holds PIT id which is used to perform broadcast operation in PIT shards to retrieve segments information
+     */
+    public class PitAwareShardRouting extends ShardRouting {
+
+        private final String pitId;
+
+        public PitAwareShardRouting(StreamInput in) throws IOException {
+            super(in);
+            this.pitId = in.readString();
+        }
+
+        public PitAwareShardRouting(
+            String pitId,
+            ShardId shardId,
+            String currentNodeId,
+            String relocatingNodeId,
+            boolean primary,
+            ShardRoutingState state,
+            RecoverySource recoverySource,
+            UnassignedInfo unassignedInfo,
+            AllocationId allocationId,
+            long expectedShardSize
+        ) {
+            super(
+                shardId,
+                currentNodeId,
+                relocatingNodeId,
+                primary,
+                state,
+                recoverySource,
+                unassignedInfo,
+                allocationId,
+                expectedShardSize
+            );
+            this.pitId = pitId;
+        }
+
+        public String getPitId() {
+            return pitId;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(pitId);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            super.toXContent(builder, params);
+            builder.field("pit_id", pitId);
+            return builder.endObject();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/segments/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/segments/package-info.java
new file mode 100644
index 0000000000000..0bbd0164b8205
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/segments/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Segment level transport handlers. */
+package org.opensearch.action.admin.indices.segments;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsAction.java
index cc64009682d43..e035b4d9ef622 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for getting index segments
+ *
+ * @opensearch.internal
+ */
 public class GetSettingsAction extends ActionType<GetSettingsResponse> {
 
     public static final GetSettingsAction INSTANCE = new GetSettingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequest.java
index 739dfcae6287c..01383b6b6545d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequest.java
@@ -36,16 +36,21 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Objects;
 
-public class GetSettingsRequest extends MasterNodeReadRequest<GetSettingsRequest> implements IndicesRequest.Replaceable {
+/**
+ * Transport request for getting index segments
+ *
+ * @opensearch.internal
+ */
+public class GetSettingsRequest extends ClusterManagerNodeReadRequest<GetSettingsRequest> implements IndicesRequest.Replaceable {
 
     private String[] indices = Strings.EMPTY_ARRAY;
     private IndicesOptions indicesOptions = IndicesOptions.fromOptions(false, true, true, true);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestBuilder.java
index 034d5d64f1ca7..84cd4e8682e93 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestBuilder.java
@@ -33,11 +33,16 @@
 package org.opensearch.action.admin.indices.settings.get;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.util.ArrayUtils;
 
-public class GetSettingsRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder for getting index segments
+ *
+ * @opensearch.internal
+ */
+public class GetSettingsRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     GetSettingsRequest,
     GetSettingsResponse,
     GetSettingsRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponse.java
index 0694f93f585ee..61c9b68629194 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponse.java
@@ -32,43 +32,43 @@
 
 package org.opensearch.action.admin.indices.settings.get;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Transport response for getting index segments
+ *
+ * @opensearch.internal
+ */
 public class GetSettingsResponse extends ActionResponse implements ToXContentObject {
 
-    private final ImmutableOpenMap<String, Settings> indexToSettings;
-    private final ImmutableOpenMap<String, Settings> indexToDefaultSettings;
+    private final Map<String, Settings> indexToSettings;
+    private final Map<String, Settings> indexToDefaultSettings;
 
-    public GetSettingsResponse(
-        ImmutableOpenMap<String, Settings> indexToSettings,
-        ImmutableOpenMap<String, Settings> indexToDefaultSettings
-    ) {
-        this.indexToSettings = indexToSettings;
-        this.indexToDefaultSettings = indexToDefaultSettings;
+    public GetSettingsResponse(Map<String, Settings> indexToSettings, Map<String, Settings> indexToDefaultSettings) {
+        this.indexToSettings = Collections.unmodifiableMap(indexToSettings);
+        this.indexToDefaultSettings = Collections.unmodifiableMap(indexToDefaultSettings);
     }
 
     public GetSettingsResponse(StreamInput in) throws IOException {
         super(in);
-        indexToSettings = in.readImmutableMap(StreamInput::readString, Settings::readSettingsFromStream);
-        indexToDefaultSettings = in.readImmutableMap(StreamInput::readString, Settings::readSettingsFromStream);
+        indexToSettings = in.readMap(StreamInput::readString, Settings::readSettingsFromStream);
+        indexToDefaultSettings = in.readMap(StreamInput::readString, Settings::readSettingsFromStream);
     }
 
     /**
@@ -76,7 +76,7 @@ public GetSettingsResponse(StreamInput in) throws IOException {
      * objects contain only those settings explicitly set on a given index.  Any settings
      * taking effect as defaults must be accessed via {@link #getIndexToDefaultSettings()}.
      */
-    public ImmutableOpenMap<String, Settings> getIndexToSettings() {
+    public Map<String, Settings> getIndexToSettings() {
         return indexToSettings;
     }
 
@@ -88,7 +88,7 @@ public ImmutableOpenMap<String, Settings> getIndexToSettings() {
      * via {@link #getIndexToSettings()}.
      * See also {@link GetSettingsRequest#includeDefaults(boolean)}
      */
-    public ImmutableOpenMap<String, Settings> getIndexToDefaultSettings() {
+    public Map<String, Settings> getIndexToDefaultSettings() {
         return indexToDefaultSettings;
     }
 
@@ -180,10 +180,8 @@ public static GetSettingsResponse fromXContent(XContentParser parser) throws IOE
             }
         }
 
-        ImmutableOpenMap<String, Settings> settingsMap = ImmutableOpenMap.<String, Settings>builder().putAll(indexToSettings).build();
-        ImmutableOpenMap<String, Settings> defaultSettingsMap = ImmutableOpenMap.<String, Settings>builder()
-            .putAll(indexToDefaultSettings)
-            .build();
+        final Map<String, Settings> settingsMap = Collections.unmodifiableMap(indexToSettings);
+        final Map<String, Settings> defaultSettingsMap = Collections.unmodifiableMap(indexToDefaultSettings);
 
         return new GetSettingsResponse(settingsMap, defaultSettingsMap);
     }
@@ -194,7 +192,7 @@ public String toString() {
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             XContentBuilder builder = new XContentBuilder(JsonXContent.jsonXContent, baos);
             toXContent(builder, ToXContent.EMPTY_PARAMS, false);
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             throw new IllegalStateException(e); // should not be possible here
         }
@@ -207,18 +205,18 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     private XContentBuilder toXContent(XContentBuilder builder, Params params, boolean omitEmptySettings) throws IOException {
         builder.startObject();
-        for (ObjectObjectCursor<String, Settings> cursor : getIndexToSettings()) {
+        for (final Map.Entry<String, Settings> cursor : getIndexToSettings().entrySet()) {
             // no settings, jump over it to shorten the response data
-            if (omitEmptySettings && cursor.value.isEmpty()) {
+            if (omitEmptySettings && cursor.getValue().isEmpty()) {
                 continue;
             }
-            builder.startObject(cursor.key);
+            builder.startObject(cursor.getKey());
             builder.startObject("settings");
-            cursor.value.toXContent(builder, params);
+            cursor.getValue().toXContent(builder, params);
             builder.endObject();
             if (indexToDefaultSettings.isEmpty() == false) {
                 builder.startObject("defaults");
-                indexToDefaultSettings.get(cursor.key).toXContent(builder, params);
+                indexToDefaultSettings.get(cursor.getKey()).toXContent(builder, params);
                 builder.endObject();
             }
             builder.endObject();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/TransportGetSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/TransportGetSettingsAction.java
index 5e2c13b5037e2..d8f2180208b18 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/TransportGetSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/TransportGetSettingsAction.java
@@ -32,30 +32,36 @@
 
 package org.opensearch.action.admin.indices.settings.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
 
-public class TransportGetSettingsAction extends TransportMasterNodeReadAction<GetSettingsRequest, GetSettingsResponse> {
+/**
+ * Transport action for getting index settings
+ *
+ * @opensearch.internal
+ */
+public class TransportGetSettingsAction extends TransportClusterManagerNodeReadAction<GetSettingsRequest, GetSettingsResponse> {
 
     private final SettingsFilter settingsFilter;
     private final IndexScopedSettings indexScopedSettings;
@@ -105,10 +111,10 @@ private static boolean isFilteredRequest(GetSettingsRequest request) {
     }
 
     @Override
-    protected void masterOperation(GetSettingsRequest request, ClusterState state, ActionListener<GetSettingsResponse> listener) {
+    protected void clusterManagerOperation(GetSettingsRequest request, ClusterState state, ActionListener<GetSettingsResponse> listener) {
         Index[] concreteIndices = indexNameExpressionResolver.concreteIndices(state, request);
-        ImmutableOpenMap.Builder<String, Settings> indexToSettingsBuilder = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, Settings> indexToDefaultSettingsBuilder = ImmutableOpenMap.builder();
+        final Map<String, Settings> indexToSettingsBuilder = new HashMap<>();
+        final Map<String, Settings> indexToDefaultSettingsBuilder = new HashMap<>();
         for (Index concreteIndex : concreteIndices) {
             IndexMetadata indexMetadata = state.getMetadata().index(concreteIndex);
             if (indexMetadata == null) {
@@ -133,6 +139,6 @@ protected void masterOperation(GetSettingsRequest request, ClusterState state, A
                 indexToDefaultSettingsBuilder.put(concreteIndex.getName(), defaultSettings);
             }
         }
-        listener.onResponse(new GetSettingsResponse(indexToSettingsBuilder.build(), indexToDefaultSettingsBuilder.build()));
+        listener.onResponse(new GetSettingsResponse(indexToSettingsBuilder, indexToDefaultSettingsBuilder));
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/package-info.java
new file mode 100644
index 0000000000000..e767b1a8870e0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Index Settings transport handler. */
+package org.opensearch.action.admin.indices.settings.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/package-info.java
new file mode 100644
index 0000000000000..862dfad419bd4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Settings transport handlers. */
+package org.opensearch.action.admin.indices.settings;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
index 8b81bb8d8a821..1c57dc27df8c6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -48,17 +47,41 @@
 import org.opensearch.cluster.metadata.MetadataUpdateSettingsService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexModule;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.Set;
+import java.util.stream.Stream;
 
-public class TransportUpdateSettingsAction extends TransportMasterNodeAction<UpdateSettingsRequest, AcknowledgedResponse> {
+import static org.opensearch.index.IndexModule.INDEX_STORE_TYPE_SETTING;
+
+/**
+ * Transport action for updating index settings
+ *
+ * @opensearch.internal
+ */
+public class TransportUpdateSettingsAction extends TransportClusterManagerNodeAction<UpdateSettingsRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportUpdateSettingsAction.class);
 
+    private final static Set<String> ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS = Set.of(
+        "index.max_result_window",
+        "index.max_inner_result_window",
+        "index.max_rescore_window",
+        "index.max_docvalue_fields_search",
+        "index.max_script_fields",
+        "index.max_terms_count",
+        "index.max_regex_length",
+        "index.highlight.max_analyzed_offset"
+    );
+
+    private final static String[] ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS_PREFIXES = { "index.search.slowlog" };
+
     private final MetadataUpdateSettingsService updateSettingsService;
 
     @Inject
@@ -101,8 +124,31 @@ protected ClusterBlockException checkBlock(UpdateSettingsRequest request, Cluste
             || IndexMetadata.INDEX_BLOCKS_READ_ONLY_ALLOW_DELETE_SETTING.exists(request.settings())) {
             return null;
         }
-        return state.blocks()
-            .indicesBlockedException(ClusterBlockLevel.METADATA_WRITE, indexNameExpressionResolver.concreteIndexNames(state, request));
+
+        final Index[] requestIndices = indexNameExpressionResolver.concreteIndices(state, request);
+        boolean allowSearchableSnapshotSettingsUpdate = true;
+        // check if all indices in the request are remote snapshot
+        for (Index index : requestIndices) {
+            if (state.blocks().indexBlocked(ClusterBlockLevel.METADATA_WRITE, index.getName())) {
+                allowSearchableSnapshotSettingsUpdate = allowSearchableSnapshotSettingsUpdate
+                    && IndexModule.Type.REMOTE_SNAPSHOT.match(
+                        state.getMetadata().getIndexSafe(index).getSettings().get(INDEX_STORE_TYPE_SETTING.getKey())
+                    );
+            }
+        }
+        // check if all settings in the request are in the allow list
+        if (allowSearchableSnapshotSettingsUpdate) {
+            for (String setting : request.settings().keySet()) {
+                allowSearchableSnapshotSettingsUpdate = allowSearchableSnapshotSettingsUpdate
+                    && (ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS.contains(setting)
+                        || Stream.of(ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS_PREFIXES).anyMatch(setting::startsWith));
+            }
+        }
+
+        return allowSearchableSnapshotSettingsUpdate
+            ? null
+            : state.blocks()
+                .indicesBlockedException(ClusterBlockLevel.METADATA_WRITE, indexNameExpressionResolver.concreteIndexNames(state, request));
     }
 
     @Override
@@ -111,7 +157,7 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final UpdateSettingsRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -123,7 +169,7 @@ protected void masterOperation(
             .settings(request.settings())
             .setPreserveExisting(request.isPreserveExisting())
             .ackTimeout(request.timeout())
-            .masterNodeTimeout(request.masterNodeTimeout());
+            .masterNodeTimeout(request.clusterManagerNodeTimeout());
 
         updateSettingsService.updateSettings(clusterStateUpdateRequest, new ActionListener<ClusterStateUpdateResponse>() {
             @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsAction.java
index 7c0182b0704de..2333a2aad6bc6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Action for updating index settings
+ *
+ * @opensearch.internal
+ */
 public class UpdateSettingsAction extends ActionType<AcknowledgedResponse> {
 
     public static final UpdateSettingsAction INSTANCE = new UpdateSettingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsClusterStateUpdateRequest.java
index ce36e01ac465e..4b0dd05575309 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsClusterStateUpdateRequest.java
@@ -37,6 +37,8 @@
 
 /**
  * Cluster state update request that allows to update settings for some indices
+ *
+ * @opensearch.internal
  */
 public class UpdateSettingsClusterStateUpdateRequest extends IndicesClusterStateUpdateRequest<UpdateSettingsClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
index 70f3dc683d599..43571dc8220f9 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
@@ -36,14 +36,15 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -52,12 +53,14 @@
 import java.util.Objects;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
-import static org.opensearch.common.settings.Settings.Builder.EMPTY_SETTINGS;
 
 /**
  * Request for an update index settings action
+ *
+ * @opensearch.internal
  */
 public class UpdateSettingsRequest extends AcknowledgedRequest<UpdateSettingsRequest>
     implements
@@ -155,8 +158,8 @@ public UpdateSettingsRequest settings(Settings.Builder settings) {
     /**
      * Sets the settings to be updated (either json or yaml format)
      */
-    public UpdateSettingsRequest settings(String source, XContentType xContentType) {
-        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+    public UpdateSettingsRequest settings(String source, MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -219,7 +222,7 @@ public UpdateSettingsRequest fromXContent(XContentParser parser) throws IOExcept
 
     @Override
     public String toString() {
-        return "indices : " + Arrays.toString(indices) + "," + Strings.toString(this);
+        return "indices : " + Arrays.toString(indices) + "," + Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
@@ -231,7 +234,7 @@ public boolean equals(Object o) {
             return false;
         }
         UpdateSettingsRequest that = (UpdateSettingsRequest) o;
-        return masterNodeTimeout.equals(that.masterNodeTimeout)
+        return clusterManagerNodeTimeout.equals(that.clusterManagerNodeTimeout)
             && timeout.equals(that.timeout)
             && Objects.equals(settings, that.settings)
             && Objects.equals(indicesOptions, that.indicesOptions)
@@ -241,7 +244,7 @@ public boolean equals(Object o) {
 
     @Override
     public int hashCode() {
-        return Objects.hash(masterNodeTimeout, timeout, settings, indicesOptions, preserveExisting, Arrays.hashCode(indices));
+        return Objects.hash(clusterManagerNodeTimeout, timeout, settings, indicesOptions, preserveExisting, Arrays.hashCode(indices));
     }
 
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
index dd3b78ce901f4..7501f0c7798de 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
@@ -43,6 +43,8 @@
 
 /**
  * Builder for an update index settings request
+ *
+ * @opensearch.internal
  */
 public class UpdateSettingsRequestBuilder extends AcknowledgedRequestBuilder<
     UpdateSettingsRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/package-info.java
new file mode 100644
index 0000000000000..dc38136b72d57
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Put Settings transport handler. */
+package org.opensearch.action.admin.indices.settings.put;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestBuilder.java
index 8a5b8bea75119..bc9633f2bd2db 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreRequestBuilder.java
@@ -34,14 +34,16 @@
 
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 
 /**
  * Request builder for {@link IndicesShardStoresRequest}
+ *
+ * @opensearch.internal
  */
-public class IndicesShardStoreRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+public class IndicesShardStoreRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     IndicesShardStoresRequest,
     IndicesShardStoresResponse,
     IndicesShardStoreRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresAction.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresAction.java
index ec67ae051a5b1..79a6f88b1dbc4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresAction.java
@@ -40,6 +40,8 @@
  * Exposes shard store information for requested indices.
  * Shard store information reports which nodes hold shard copies, how recent they are
  * and any exceptions on opening the shard index or from previous engine failures
+ *
+ * @opensearch.internal
  */
 public class IndicesShardStoresAction extends ActionType<IndicesShardStoresResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresRequest.java
index ff5b5c4cf0c2a..d3261bea68f38 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresRequest.java
@@ -34,19 +34,23 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.cluster.health.ClusterHealthStatus;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.EnumSet;
 
 /**
  * Request for {@link IndicesShardStoresAction}
+ *
+ * @opensearch.internal
  */
-public class IndicesShardStoresRequest extends MasterNodeReadRequest<IndicesShardStoresRequest> implements IndicesRequest.Replaceable {
+public class IndicesShardStoresRequest extends ClusterManagerNodeReadRequest<IndicesShardStoresRequest>
+    implements
+        IndicesRequest.Replaceable {
 
     private String[] indices = Strings.EMPTY_ARRAY;
     private IndicesOptions indicesOptions = IndicesOptions.strictExpand();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresResponse.java
index d09bf99ca7258..fae5a62b6ebbc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/IndicesShardStoresResponse.java
@@ -32,35 +32,36 @@
 
 package org.opensearch.action.admin.indices.shards;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Response for {@link IndicesShardStoresAction}
  *
  * Consists of {@link StoreStatus}s for requested indices grouped by
  * indices and shard ids and a list of encountered node {@link Failure}s
+ *
+ * @opensearch.internal
  */
 public class IndicesShardStoresResponse extends ActionResponse implements ToXContentFragment {
 
     /**
      * Shard store information from a node
+     *
+     * @opensearch.internal
      */
     public static class StoreStatus implements Writeable, ToXContentFragment, Comparable<StoreStatus> {
         private final DiscoveryNode node;
@@ -231,6 +232,8 @@ public int compareTo(StoreStatus other) {
 
     /**
      * Single node failure while retrieving shard store information
+     *
+     * @opensearch.internal
      */
     public static class Failure extends DefaultShardOperationFailedException {
         private String nodeId;
@@ -276,31 +279,25 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
         }
     }
 
-    private final ImmutableOpenMap<String, ImmutableOpenIntMap<List<StoreStatus>>> storeStatuses;
+    private final Map<String, Map<Integer, List<StoreStatus>>> storeStatuses;
     private final List<Failure> failures;
 
-    public IndicesShardStoresResponse(
-        ImmutableOpenMap<String, ImmutableOpenIntMap<List<StoreStatus>>> storeStatuses,
-        List<Failure> failures
-    ) {
-        this.storeStatuses = storeStatuses;
+    public IndicesShardStoresResponse(final Map<String, Map<Integer, List<StoreStatus>>> storeStatuses, List<Failure> failures) {
+        this.storeStatuses = Collections.unmodifiableMap(storeStatuses);
         this.failures = failures;
     }
 
     IndicesShardStoresResponse() {
-        this(ImmutableOpenMap.of(), Collections.emptyList());
+        this(Map.of(), Collections.emptyList());
     }
 
     public IndicesShardStoresResponse(StreamInput in) throws IOException {
         super(in);
-        storeStatuses = in.readImmutableMap(StreamInput::readString, i -> {
-            int indexEntries = i.readVInt();
-            ImmutableOpenIntMap.Builder<List<StoreStatus>> shardEntries = ImmutableOpenIntMap.builder();
-            for (int shardCount = 0; shardCount < indexEntries; shardCount++) {
-                shardEntries.put(i.readInt(), i.readList(StoreStatus::new));
-            }
-            return shardEntries.build();
-        });
+        final Map<String, Map<Integer, List<StoreStatus>>> storeStatuses = in.readMap(
+            StreamInput::readString,
+            i -> i.readMap(StreamInput::readInt, j -> j.readList(StoreStatus::new))
+        );
+        this.storeStatuses = Collections.unmodifiableMap(storeStatuses);
         failures = Collections.unmodifiableList(in.readList(Failure::readFailure));
     }
 
@@ -308,7 +305,7 @@ public IndicesShardStoresResponse(StreamInput in) throws IOException {
      * Returns {@link StoreStatus}s
      * grouped by their index names and shard ids.
      */
-    public ImmutableOpenMap<String, ImmutableOpenIntMap<List<StoreStatus>>> getStoreStatuses() {
+    public Map<String, Map<Integer, List<StoreStatus>>> getStoreStatuses() {
         return storeStatuses;
     }
 
@@ -322,13 +319,11 @@ public List<Failure> getFailures() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(storeStatuses, StreamOutput::writeString, (o, v) -> {
-            o.writeVInt(v.size());
-            for (IntObjectCursor<List<StoreStatus>> shardStatusesEntry : v) {
-                o.writeInt(shardStatusesEntry.key);
-                o.writeCollection(shardStatusesEntry.value);
-            }
-        });
+        out.writeMap(
+            storeStatuses,
+            StreamOutput::writeString,
+            (o, v) -> o.writeMap(v, StreamOutput::writeInt, StreamOutput::writeCollection)
+        );
         out.writeList(failures);
     }
 
@@ -343,14 +338,14 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
 
         builder.startObject(Fields.INDICES);
-        for (ObjectObjectCursor<String, ImmutableOpenIntMap<List<StoreStatus>>> indexShards : storeStatuses) {
-            builder.startObject(indexShards.key);
+        for (final Map.Entry<String, Map<Integer, List<StoreStatus>>> indexShards : storeStatuses.entrySet()) {
+            builder.startObject(indexShards.getKey());
 
             builder.startObject(Fields.SHARDS);
-            for (IntObjectCursor<List<StoreStatus>> shardStatusesEntry : indexShards.value) {
-                builder.startObject(String.valueOf(shardStatusesEntry.key));
+            for (final Map.Entry<Integer, List<StoreStatus>> shardStatusesEntry : indexShards.getValue().entrySet()) {
+                builder.startObject(String.valueOf(shardStatusesEntry.getKey()));
                 builder.startArray(Fields.STORES);
-                for (StoreStatus storeStatus : shardStatusesEntry.value) {
+                for (StoreStatus storeStatus : shardStatusesEntry.getValue()) {
                     builder.startObject();
                     storeStatus.toXContent(builder, params);
                     builder.endObject();
@@ -367,6 +362,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String INDICES = "indices";
         static final String SHARDS = "shards";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/TransportIndicesShardStoresAction.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/TransportIndicesShardStoresAction.java
index 32acd9e305130..41225bc362235 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shards/TransportIndicesShardStoresAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/TransportIndicesShardStoresAction.java
@@ -34,10 +34,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.CollectionUtil;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -53,24 +52,25 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.gateway.AsyncShardFetch;
 import org.opensearch.gateway.TransportNodesListGatewayStartedShards;
 import org.opensearch.gateway.TransportNodesListGatewayStartedShards.NodeGatewayStartedShards;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Queue;
 import java.util.Set;
 import java.util.concurrent.ConcurrentLinkedQueue;
@@ -78,8 +78,10 @@
 /**
  * Transport action that reads the cluster state for shards with the requested criteria (see {@link ClusterHealthStatus}) of specific
  * indices and fetches store information from all the nodes using {@link TransportNodesListGatewayStartedShards}
+ *
+ * @opensearch.internal
  */
-public class TransportIndicesShardStoresAction extends TransportMasterNodeReadAction<
+public class TransportIndicesShardStoresAction extends TransportClusterManagerNodeReadAction<
     IndicesShardStoresRequest,
     IndicesShardStoresResponse> {
 
@@ -119,7 +121,7 @@ protected IndicesShardStoresResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         IndicesShardStoresRequest request,
         ClusterState state,
         ActionListener<IndicesShardStoresResponse> listener
@@ -160,6 +162,11 @@ protected ClusterBlockException checkBlock(IndicesShardStoresRequest request, Cl
             .indicesBlockedException(ClusterBlockLevel.METADATA_READ, indexNameExpressionResolver.concreteIndexNames(state, request));
     }
 
+    /**
+     * Information for async shard stores
+     *
+     * @opensearch.internal
+     */
     private class AsyncShardStoresInfoFetches {
         private final DiscoveryNodes nodes;
         private final RoutingNodes routingNodes;
@@ -193,6 +200,11 @@ void start() {
             }
         }
 
+        /**
+         * Internal async fetch
+         *
+         * @opensearch.internal
+         */
         private class InternalAsyncFetch extends AsyncShardFetch<NodeGatewayStartedShards> {
 
             InternalAsyncFetch(
@@ -218,20 +230,17 @@ protected synchronized void processAsyncFetch(
             }
 
             void finish() {
-                ImmutableOpenMap.Builder<
-                    String,
-                    ImmutableOpenIntMap<java.util.List<IndicesShardStoresResponse.StoreStatus>>> indicesStoreStatusesBuilder =
-                        ImmutableOpenMap.builder();
+                final Map<String, Map<Integer, List<IndicesShardStoresResponse.StoreStatus>>> indicesStoreStatusesBuilder = new HashMap<>();
 
                 java.util.List<IndicesShardStoresResponse.Failure> failureBuilder = new ArrayList<>();
                 for (Response fetchResponse : fetchResponses) {
-                    ImmutableOpenIntMap<java.util.List<IndicesShardStoresResponse.StoreStatus>> indexStoreStatuses =
+                    final Map<Integer, java.util.List<IndicesShardStoresResponse.StoreStatus>> indexStoreStatuses =
                         indicesStoreStatusesBuilder.get(fetchResponse.shardId.getIndexName());
-                    final ImmutableOpenIntMap.Builder<java.util.List<IndicesShardStoresResponse.StoreStatus>> indexShardsBuilder;
+                    final Map<Integer, java.util.List<IndicesShardStoresResponse.StoreStatus>> indexShardsBuilder;
                     if (indexStoreStatuses == null) {
-                        indexShardsBuilder = ImmutableOpenIntMap.builder();
+                        indexShardsBuilder = new HashMap<>();
                     } else {
-                        indexShardsBuilder = ImmutableOpenIntMap.builder(indexStoreStatuses);
+                        indexShardsBuilder = new HashMap<>(indexStoreStatuses);
                     }
                     java.util.List<IndicesShardStoresResponse.StoreStatus> storeStatuses = indexShardsBuilder.get(
                         fetchResponse.shardId.id()
@@ -258,7 +267,7 @@ void finish() {
                     }
                     CollectionUtil.timSort(storeStatuses);
                     indexShardsBuilder.put(fetchResponse.shardId.id(), storeStatuses);
-                    indicesStoreStatusesBuilder.put(fetchResponse.shardId.getIndexName(), indexShardsBuilder.build());
+                    indicesStoreStatusesBuilder.put(fetchResponse.shardId.getIndexName(), Collections.unmodifiableMap(indexShardsBuilder));
                     for (FailedNodeException failure : fetchResponse.failures) {
                         failureBuilder.add(
                             new IndicesShardStoresResponse.Failure(
@@ -271,7 +280,7 @@ void finish() {
                     }
                 }
                 listener.onResponse(
-                    new IndicesShardStoresResponse(indicesStoreStatusesBuilder.build(), Collections.unmodifiableList(failureBuilder))
+                    new IndicesShardStoresResponse(indicesStoreStatusesBuilder, Collections.unmodifiableList(failureBuilder))
                 );
             }
 
@@ -307,6 +316,11 @@ protected void reroute(ShardId shardId, String reason) {
                 // no-op
             }
 
+            /**
+             * Response for shard stores action
+             *
+             * @opensearch.internal
+             */
             public class Response {
                 private final ShardId shardId;
                 private final List<NodeGatewayStartedShards> responses;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shards/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/shards/package-info.java
new file mode 100644
index 0000000000000..187ffc0714e7e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shards/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Shards transport handlers. */
+package org.opensearch.action.admin.indices.shards;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeAction.java
index 5ecdd62206177..7ea6391f1c429 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for resizing an index
+ *
+ * @opensearch.internal
+ */
 public class ResizeAction extends ActionType<ResizeResponse> {
 
     public static final ResizeAction INSTANCE = new ResizeAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequest.java
index b74c6c8f8d195..ea6892126dc65 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequest.java
@@ -32,6 +32,7 @@
 package org.opensearch.action.admin.indices.shrink;
 
 import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.admin.indices.alias.Alias;
@@ -40,13 +41,14 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -55,10 +57,14 @@
 
 /**
  * Request class to shrink an index into a single shard
+ *
+ * @opensearch.internal
  */
 public class ResizeRequest extends AcknowledgedRequest<ResizeRequest> implements IndicesRequest, ToXContentObject {
 
     public static final ObjectParser<ResizeRequest, Void> PARSER = new ObjectParser<>("resize_request");
+    private static final ParseField MAX_SHARD_SIZE = new ParseField("max_shard_size");
+
     static {
         PARSER.declareField(
             (parser, request, context) -> request.getTargetIndexRequest().settings(parser.map()),
@@ -70,12 +76,20 @@ public class ResizeRequest extends AcknowledgedRequest<ResizeRequest> implements
             new ParseField("aliases"),
             ObjectParser.ValueType.OBJECT
         );
+        PARSER.declareField(
+            ResizeRequest::setMaxShardSize,
+            (p, c) -> ByteSizeValue.parseBytesSizeValue(p.text(), MAX_SHARD_SIZE.getPreferredName()),
+            MAX_SHARD_SIZE,
+            ObjectParser.ValueType.STRING
+        );
     }
 
     private CreateIndexRequest targetIndexRequest;
     private String sourceIndex;
     private ResizeType type = ResizeType.SHRINK;
     private Boolean copySettings = true;
+    private ByteSizeValue maxShardSize;
+    private boolean shouldStoreResult;
 
     public ResizeRequest(StreamInput in) throws IOException {
         super(in);
@@ -83,6 +97,9 @@ public ResizeRequest(StreamInput in) throws IOException {
         sourceIndex = in.readString();
         type = in.readEnum(ResizeType.class);
         copySettings = in.readOptionalBoolean();
+        if (in.getVersion().onOrAfter(Version.V_2_5_0)) {
+            maxShardSize = in.readOptionalWriteable(ByteSizeValue::new);
+        }
     }
 
     ResizeRequest() {}
@@ -104,9 +121,53 @@ public ActionRequestValidationException validate() {
         if (targetIndexRequest.settings().getByPrefix("index.sort.").isEmpty() == false) {
             validationException = addValidationError("can't override index sort when resizing an index", validationException);
         }
+        if (IndexMetadata.INDEX_ROUTING_PARTITION_SIZE_SETTING.exists(targetIndexRequest.settings())) {
+            validationException = addValidationError(
+                "cannot provide a routing partition size value when resizing an index",
+                validationException
+            );
+        }
         if (type == ResizeType.SPLIT && IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.exists(targetIndexRequest.settings()) == false) {
             validationException = addValidationError("index.number_of_shards is required for split operations", validationException);
         }
+
+        // max_shard_size is only supported for shrink
+        if (type != ResizeType.SHRINK && maxShardSize != null) {
+            validationException = addValidationError("Unsupported parameter [max_shard_size]", validationException);
+        }
+        // max_shard_size conflicts with the index.number_of_shards setting
+        if (type == ResizeType.SHRINK
+            && IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.exists(targetIndexRequest.settings())
+            && maxShardSize != null) {
+            validationException = addValidationError(
+                "Cannot set max_shard_size and index.number_of_shards at the same time!",
+                validationException
+            );
+        }
+        if (maxShardSize != null && maxShardSize.getBytes() <= 0) {
+            validationException = addValidationError("max_shard_size must be greater than 0", validationException);
+        }
+        // Check target index's settings, if `index.blocks.read_only` is `true`, the target index's metadata writes will be disabled
+        // and then cause the new shards to be unassigned.
+        if (IndexMetadata.INDEX_READ_ONLY_SETTING.get(targetIndexRequest.settings()) == true) {
+            validationException = addValidationError(
+                "target index ["
+                    + targetIndexRequest.index()
+                    + "] will be blocked by [index.blocks.read_only=true], this will disable metadata writes and cause the shards to be unassigned",
+                validationException
+            );
+        }
+
+        // Check target index's settings, if `index.blocks.metadata` is `true`, the target index's metadata writes will be disabled
+        // and then cause the new shards to be unassigned.
+        if (IndexMetadata.INDEX_BLOCKS_METADATA_SETTING.get(targetIndexRequest.settings()) == true) {
+            validationException = addValidationError(
+                "target index ["
+                    + targetIndexRequest.index()
+                    + "] will be blocked by [index.blocks.metadata=true], this will disable metadata writes and cause the shards to be unassigned",
+                validationException
+            );
+        }
         assert copySettings == null || copySettings;
         return validationException;
     }
@@ -125,6 +186,9 @@ public void writeTo(StreamOutput out) throws IOException {
         }
         out.writeEnum(type);
         out.writeOptionalBoolean(copySettings);
+        if (out.getVersion().onOrAfter(Version.V_2_5_0)) {
+            out.writeOptionalWriteable(maxShardSize);
+        }
     }
 
     @Override
@@ -207,6 +271,36 @@ public Boolean getCopySettings() {
         return copySettings;
     }
 
+    /**
+     * Sets the maximum size of a primary shard in the new shrunken index.
+     * This parameter can be used to calculate the lowest factor of the source index's shards number
+     * which satisfies the maximum shard size requirement.
+     *
+     * @param maxShardSize the maximum size of a primary shard in the new shrunken index
+     */
+    public void setMaxShardSize(ByteSizeValue maxShardSize) {
+        this.maxShardSize = maxShardSize;
+    }
+
+    /**
+     * Returns the maximum size of a primary shard in the new shrunken index.
+     */
+    public ByteSizeValue getMaxShardSize() {
+        return maxShardSize;
+    }
+
+    /**
+     * Should this task store its result after it has finished?
+     */
+    public void setShouldStoreResult(boolean shouldStoreResult) {
+        this.shouldStoreResult = shouldStoreResult;
+    }
+
+    @Override
+    public boolean getShouldStoreResult() {
+        return shouldStoreResult;
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject();
@@ -223,6 +317,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                 }
             }
             builder.endObject();
+            if (maxShardSize != null) {
+                builder.field(MAX_SHARD_SIZE.getPreferredName(), maxShardSize);
+            }
         }
         builder.endObject();
         return builder;
@@ -231,4 +328,27 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     public void fromXContent(XContentParser parser) throws IOException {
         PARSER.parse(parser, this, null);
     }
+
+    @Override
+    public String toString() {
+        StringBuilder b = new StringBuilder();
+        switch (getResizeType()) {
+            case SPLIT:
+                b.append("split from");
+                break;
+            case CLONE:
+                b.append("clone from");
+                break;
+            default:
+                b.append("shrink from");
+        }
+        b.append(" [").append(sourceIndex).append("]");
+        b.append(" to [").append(getTargetIndexRequest().index()).append(']');
+        return b.toString();
+    }
+
+    @Override
+    public String getDescription() {
+        return this.toString();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequestBuilder.java
index 766ed78e63497..855e678c77b9b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeRequestBuilder.java
@@ -37,7 +37,13 @@
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
+/**
+ * Transport request builder for resizing an index
+ *
+ * @opensearch.internal
+ */
 public class ResizeRequestBuilder extends AcknowledgedRequestBuilder<ResizeRequest, ResizeResponse, ResizeRequestBuilder> {
     public ResizeRequestBuilder(OpenSearchClient client, ActionType<ResizeResponse> action) {
         super(client, action, new ResizeRequest());
@@ -90,4 +96,12 @@ public ResizeRequestBuilder setResizeType(ResizeType type) {
         this.request.setResizeType(type);
         return this;
     }
+
+    /**
+     * Sets the maximum size of a primary shard in the new shrunken index.
+     */
+    public ResizeRequestBuilder setMaxShardSize(ByteSizeValue maxShardSize) {
+        this.request.setMaxShardSize(maxShardSize);
+        return this;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeResponse.java
index 3846591d26f3a..1aa09023e3583 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeResponse.java
@@ -33,14 +33,16 @@
 package org.opensearch.action.admin.indices.shrink;
 
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * A response for a resize index action, either shrink or split index.
+ *
+ * @opensearch.internal
  */
 public final class ResizeResponse extends CreateIndexResponse {
 
@@ -65,4 +67,14 @@ public ResizeResponse(boolean acknowledged, boolean shardsAcknowledged, String i
     public static ResizeResponse fromXContent(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append(getClass().getSimpleName()).append("[");
+        builder.append("acknowledged=").append(isAcknowledged()).append(',');
+        builder.append("shards_acknowledged=").append(isShardsAcknowledged()).append(',');
+        builder.append("index=").append(index());
+        return builder.append(']').toString();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeType.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeType.java
index 62b20ed9d3dcf..6403ed735ae49 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeType.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ResizeType.java
@@ -34,6 +34,8 @@
 
 /**
  * The type of the resize operation
+ *
+ * @opensearch.internal
  */
 public enum ResizeType {
     SHRINK,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ShrinkAction.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/ShrinkAction.java
deleted file mode 100644
index 1fa894b265573..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/ShrinkAction.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.shrink;
-
-import org.opensearch.action.ActionType;
-
-public class ShrinkAction extends ActionType<ResizeResponse> {
-
-    public static final ShrinkAction INSTANCE = new ShrinkAction();
-    public static final String NAME = "indices:admin/shrink";
-
-    private ShrinkAction() {
-        super(NAME, ResizeResponse::new);
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/TransportResizeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/TransportResizeAction.java
index b35febe60af31..23cd8efdcaf59 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/shrink/TransportResizeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/TransportResizeAction.java
@@ -33,12 +33,11 @@
 package org.opensearch.action.admin.indices.shrink;
 
 import org.apache.lucene.index.IndexWriter;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.create.CreateIndexClusterStateUpdateRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
 import org.opensearch.action.admin.indices.stats.IndexShardStats;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -49,12 +48,15 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.DocsStats;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.store.StoreStats;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -64,10 +66,14 @@
 import java.util.Set;
 import java.util.function.IntFunction;
 
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+
 /**
  * Main class to initiate resizing (shrink / split) an index into a new index
+ *
+ * @opensearch.internal
  */
-public class TransportResizeAction extends TransportMasterNodeAction<ResizeRequest, ResizeResponse> {
+public class TransportResizeAction extends TransportClusterManagerNodeAction<ResizeRequest, ResizeResponse> {
     private final MetadataCreateIndexService createIndexService;
     private final Client client;
 
@@ -125,7 +131,7 @@ protected ClusterBlockException checkBlock(ResizeRequest request, ClusterState s
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final ResizeRequest resizeRequest,
         final ClusterState state,
         final ActionListener<ResizeResponse> listener
@@ -134,24 +140,78 @@ protected void masterOperation(
         // there is no need to fetch docs stats for split but we keep it simple and do it anyway for simplicity of the code
         final String sourceIndex = indexNameExpressionResolver.resolveDateMathExpression(resizeRequest.getSourceIndex());
         final String targetIndex = indexNameExpressionResolver.resolveDateMathExpression(resizeRequest.getTargetIndexRequest().index());
-        client.admin()
-            .indices()
-            .prepareStats(sourceIndex)
-            .clear()
-            .setDocs(true)
-            .execute(ActionListener.delegateFailure(listener, (delegatedListener, indicesStatsResponse) -> {
-                CreateIndexClusterStateUpdateRequest updateRequest = prepareCreateIndexRequest(resizeRequest, state, i -> {
-                    IndexShardStats shard = indicesStatsResponse.getIndex(sourceIndex).getIndexShards().get(i);
-                    return shard == null ? null : shard.getPrimary().getDocs();
-                }, sourceIndex, targetIndex);
-                createIndexService.createIndex(
-                    updateRequest,
-                    ActionListener.map(
-                        delegatedListener,
-                        response -> new ResizeResponse(response.isAcknowledged(), response.isShardsAcknowledged(), updateRequest.index())
-                    )
-                );
-            }));
+
+        IndexMetadata indexMetadata = state.metadata().index(sourceIndex);
+        if (resizeRequest.getResizeType().equals(ResizeType.SHRINK)
+            && state.metadata().isSegmentReplicationEnabled(sourceIndex)
+            && indexMetadata != null
+            && Integer.valueOf(indexMetadata.getSettings().get(SETTING_NUMBER_OF_REPLICAS)) > 0) {
+            client.admin()
+                .indices()
+                .prepareRefresh(sourceIndex)
+                .execute(ActionListener.delegateFailure(listener, (delegatedRefreshListener, refreshResponse) -> {
+                    client.admin()
+                        .indices()
+                        .prepareStats(sourceIndex)
+                        .clear()
+                        .setDocs(true)
+                        .setStore(true)
+                        .setSegments(true)
+                        .execute(ActionListener.delegateFailure(listener, (delegatedIndicesStatsListener, indicesStatsResponse) -> {
+                            CreateIndexClusterStateUpdateRequest updateRequest = prepareCreateIndexRequest(resizeRequest, state, i -> {
+                                IndexShardStats shard = indicesStatsResponse.getIndex(sourceIndex).getIndexShards().get(i);
+                                return shard == null ? null : shard.getPrimary().getDocs();
+                            }, indicesStatsResponse.getPrimaries().store, sourceIndex, targetIndex);
+
+                            if (indicesStatsResponse.getIndex(sourceIndex)
+                                .getTotal()
+                                .getSegments()
+                                .getReplicationStats().maxBytesBehind != 0) {
+                                throw new IllegalStateException(
+                                    " For index ["
+                                        + sourceIndex
+                                        + "] replica shards haven't caught up with primary, please retry after sometime."
+                                );
+                            }
+
+                            createIndexService.createIndex(
+                                updateRequest,
+                                ActionListener.map(
+                                    delegatedIndicesStatsListener,
+                                    response -> new ResizeResponse(
+                                        response.isAcknowledged(),
+                                        response.isShardsAcknowledged(),
+                                        updateRequest.index()
+                                    )
+                                )
+                            );
+                        }));
+                }));
+        } else {
+            client.admin()
+                .indices()
+                .prepareStats(sourceIndex)
+                .clear()
+                .setDocs(true)
+                .setStore(true)
+                .execute(ActionListener.delegateFailure(listener, (delegatedListener, indicesStatsResponse) -> {
+                    CreateIndexClusterStateUpdateRequest updateRequest = prepareCreateIndexRequest(resizeRequest, state, i -> {
+                        IndexShardStats shard = indicesStatsResponse.getIndex(sourceIndex).getIndexShards().get(i);
+                        return shard == null ? null : shard.getPrimary().getDocs();
+                    }, indicesStatsResponse.getPrimaries().store, sourceIndex, targetIndex);
+                    createIndexService.createIndex(
+                        updateRequest,
+                        ActionListener.map(
+                            delegatedListener,
+                            response -> new ResizeResponse(
+                                response.isAcknowledged(),
+                                response.isShardsAcknowledged(),
+                                updateRequest.index()
+                            )
+                        )
+                    );
+                }));
+        }
 
     }
 
@@ -160,6 +220,7 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
         final ResizeRequest resizeRequest,
         final ClusterState state,
         final IntFunction<DocsStats> perShardDocStats,
+        final StoreStats primaryShardsStoreStats,
         String sourceIndexName,
         String targetIndexName
     ) {
@@ -174,12 +235,28 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
         targetIndexSettingsBuilder.remove(IndexMetadata.SETTING_HISTORY_UUID);
         final Settings targetIndexSettings = targetIndexSettingsBuilder.build();
         final int numShards;
+
+        // We should check the source index's setting `index.blocks.read_only`, because the setting will be copied to target index,
+        // it will block target index's metadata writes and then cause the new shards to be unassigned,
+        // but if user overwrites the setting to `false` or `null`, everything is fine.
+        // We don't need to check the setting `index.blocks.metadata`, because it was checked when fetching index stats
+        if (IndexMetadata.INDEX_READ_ONLY_SETTING.get(metadata.getSettings()) == true
+            && IndexMetadata.INDEX_READ_ONLY_SETTING.exists(targetIndexSettings) == false) {
+            throw new IllegalArgumentException(
+                "target index ["
+                    + targetIndexName
+                    + "] will be blocked by [index.blocks.read_only=true] which is copied from the source index ["
+                    + sourceIndexName
+                    + "], this will disable metadata writes and cause the shards to be unassigned"
+            );
+        }
+
         if (IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.exists(targetIndexSettings)) {
             numShards = IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.get(targetIndexSettings);
         } else {
             assert resizeRequest.getResizeType() != ResizeType.SPLIT : "split must specify the number of shards explicitly";
             if (resizeRequest.getResizeType() == ResizeType.SHRINK) {
-                numShards = 1;
+                numShards = calculateTargetIndexShardsNum(resizeRequest.getMaxShardSize(), primaryShardsStoreStats, metadata);
             } else {
                 assert resizeRequest.getResizeType() == ResizeType.CLONE;
                 numShards = metadata.getNumberOfShards();
@@ -213,9 +290,6 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
             }
         }
 
-        if (IndexMetadata.INDEX_ROUTING_PARTITION_SIZE_SETTING.exists(targetIndexSettings)) {
-            throw new IllegalArgumentException("cannot provide a routing partition size value when resizing an index");
-        }
         if (IndexMetadata.INDEX_NUMBER_OF_ROUTING_SHARDS_SETTING.exists(targetIndexSettings)) {
             // if we have a source index with 1 shards it's legal to set this
             final boolean splitFromSingleShards = resizeRequest.getResizeType() == ResizeType.SPLIT && metadata.getNumberOfShards() == 1;
@@ -239,7 +313,7 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
             // applied once we took the snapshot and if somebody messes things up and switches the index read/write and adds docs we
             // miss the mappings for everything is corrupted and hard to debug
             .ackTimeout(targetIndex.timeout())
-            .masterNodeTimeout(targetIndex.masterNodeTimeout())
+            .masterNodeTimeout(targetIndex.clusterManagerNodeTimeout())
             .settings(targetIndex.settings())
             .aliases(targetIndex.aliases())
             .waitForActiveShards(targetIndex.waitForActiveShards())
@@ -248,8 +322,48 @@ static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(
             .copySettings(resizeRequest.getCopySettings() == null ? false : resizeRequest.getCopySettings());
     }
 
+    /**
+     * Calculate target index's shards count according to max_shard_ize and the source index's storage(only primary shards included)
+     * for shrink. Target index's shards count is the lowest factor of the source index's primary shards count which satisfies the
+     * maximum shard size requirement. If max_shard_size is less than the source index's single shard size, then target index's shards count
+     * will be equal to the source index's shards count.
+     * @param maxShardSize the maximum size of a primary shard in the target index
+     * @param sourceIndexShardStoreStats primary shards' store stats of the source index
+     * @param sourceIndexMetaData source index's metadata
+     * @return target index's shards number
+     */
+    protected static int calculateTargetIndexShardsNum(
+        ByteSizeValue maxShardSize,
+        StoreStats sourceIndexShardStoreStats,
+        IndexMetadata sourceIndexMetaData
+    ) {
+        if (maxShardSize == null
+            || sourceIndexShardStoreStats == null
+            || maxShardSize.getBytes() == 0
+            || sourceIndexShardStoreStats.getSizeInBytes() == 0) {
+            return 1;
+        }
+
+        int sourceIndexShardsNum = sourceIndexMetaData.getNumberOfShards();
+        // calculate the minimum shards count according to source index's storage, ceiling ensures that the minimum shards count is never
+        // less than 1
+        int minValue = (int) Math.ceil((double) sourceIndexShardStoreStats.getSizeInBytes() / maxShardSize.getBytes());
+        // if minimum shards count is greater than the source index's shards count, then the source index's shards count will be returned
+        if (minValue >= sourceIndexShardsNum) {
+            return sourceIndexShardsNum;
+        }
+
+        // find the lowest factor of the source index's shards count here, because minimum shards count may not be a factor
+        for (int i = minValue; i < sourceIndexShardsNum; i++) {
+            if (sourceIndexShardsNum % i == 0) {
+                return i;
+            }
+        }
+        return sourceIndexShardsNum;
+    }
+
     @Override
-    protected String getMasterActionName(DiscoveryNode node) {
-        return super.getMasterActionName(node);
+    protected String getClusterManagerActionName(DiscoveryNode node) {
+        return super.getClusterManagerActionName(node);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/shrink/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/shrink/package-info.java
new file mode 100644
index 0000000000000..414095575f0d9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/shrink/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Shrink Index transport handlers. */
+package org.opensearch.action.admin.indices.shrink;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStats.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStats.java
index 2949af00a30d0..e4abaef4ddfa8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStats.java
@@ -34,13 +34,13 @@
 
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.cache.request.RequestCacheStats;
 import org.opensearch.index.engine.SegmentsStats;
@@ -65,6 +65,11 @@
 import java.util.Objects;
 import java.util.stream.Stream;
 
+/**
+ * Common Stats for OpenSearch
+ *
+ * @opensearch.internal
+ */
 public class CommonStats implements Writeable, ToXContentFragment {
 
     @Nullable
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStatsFlags.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStatsFlags.java
index e17b497ce312a..501abe269556b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStatsFlags.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/CommonStatsFlags.java
@@ -34,15 +34,20 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.EnumSet;
 
+/**
+ * Common Stats Flags for OpenSearch
+ *
+ * @opensearch.internal
+ */
 public class CommonStatsFlags implements Writeable, Cloneable {
 
     public static final CommonStatsFlags ALL = new CommonStatsFlags().all();
@@ -256,6 +261,11 @@ public CommonStatsFlags clone() {
         }
     }
 
+    /**
+     * The flags.
+     *
+     * @opensearch.internal
+     */
     public enum Flag {
         Store("store", 0),
         Indexing("indexing", 1),
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexShardStats.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexShardStats.java
index b8ecd6d4bfc3d..1635ce0bf83fc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexShardStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexShardStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.action.admin.indices.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 
+/**
+ * IndexShardStats for OpenSearch
+ *
+ * @opensearch.internal
+ */
 public class IndexShardStats implements Iterable<ShardStats>, Writeable {
 
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexStats.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexStats.java
index f0eec4ebbd27a..c98d46a0caed6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndexStats.java
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Index Stats for OpenSearch
+ *
+ * @opensearch.internal
+ */
 public class IndexStats implements Iterable<IndexShardStats> {
 
     private final String index;
@@ -127,6 +132,11 @@ public CommonStats getPrimaries() {
         return stats;
     }
 
+    /**
+     * Builder for Index Stats
+     *
+     * @opensearch.internal
+     */
     public static class IndexStatsBuilder {
         private final String indexName;
         private final String uuid;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsAction.java
index c0a56c3f00536..bee33671ee291 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for retrieving index stats
+ *
+ * @opensearch.internal
+ */
 public class IndicesStatsAction extends ActionType<IndicesStatsResponse> {
 
     public static final IndicesStatsAction INSTANCE = new IndicesStatsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequest.java
index bbe69b700b876..54f3e9b7d1a24 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequest.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.admin.indices.stats;
 
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -45,6 +45,8 @@
  * <p>
  * All the stats to be returned can be cleared using {@link #clear()}, at which point, specific
  * stats can be enabled.
+ *
+ * @opensearch.internal
  */
 public class IndicesStatsRequest extends BroadcastRequest<IndicesStatsRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequestBuilder.java
index 23c33401966b4..c211812b32c48 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsRequestBuilder.java
@@ -44,6 +44,8 @@
  * <p>
  * All the stats to be returned can be cleared using {@link #clear()}, at which point, specific
  * stats can be enabled.
+ *
+ * @opensearch.internal
  */
 public class IndicesStatsRequestBuilder extends BroadcastOperationRequestBuilder<
     IndicesStatsRequest,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponse.java
index 3614d8de6c884..6f051fa19c99f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponse.java
@@ -33,14 +33,15 @@
 package org.opensearch.action.admin.indices.stats;
 
 import org.opensearch.action.admin.indices.stats.IndexStats.IndexStatsBuilder;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -50,6 +51,11 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Transport response for retrieving indices stats
+ *
+ * @opensearch.internal
+ */
 public class IndicesStatsResponse extends BroadcastResponse {
 
     private ShardStats[] shards;
@@ -208,6 +214,11 @@ protected void addCustomXContentFields(XContentBuilder builder, Params params) t
         }
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String INDICES = "indices";
         static final String SHARDS = "shards";
@@ -215,6 +226,6 @@ static final class Fields {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, false);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, false);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/ShardStats.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/ShardStats.java
index c5d3fba2a5805..77562fa19b319 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/ShardStats.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/ShardStats.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.seqno.RetentionLeaseStats;
 import org.opensearch.index.seqno.SeqNoStats;
@@ -46,6 +46,11 @@
 
 import java.io.IOException;
 
+/**
+ * Shard Stats for OpenSearch
+ *
+ * @opensearch.internal
+ */
 public class ShardStats implements Writeable, ToXContentFragment {
 
     private ShardRouting shardRouting;
@@ -172,6 +177,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String ROUTING = "routing";
         static final String STATE = "state";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/TransportIndicesStatsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/TransportIndicesStatsAction.java
index 11ca1462787e8..747213a23f577 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/stats/TransportIndicesStatsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/TransportIndicesStatsAction.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -44,7 +43,8 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.seqno.RetentionLeaseStats;
@@ -58,6 +58,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport action for retrieving indices stats
+ *
+ * @opensearch.internal
+ */
 public class TransportIndicesStatsAction extends TransportBroadcastByNodeAction<IndicesStatsRequest, IndicesStatsResponse, ShardStats> {
 
     private final IndicesService indicesService;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/stats/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/stats/package-info.java
new file mode 100644
index 0000000000000..38241a0d3bcbb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Stats transport handlers. */
+package org.opensearch.action.admin.indices.stats;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComponentTemplateAction.java
index 1a4f0a1892ec7..1f427a349c2ea 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComponentTemplateAction.java
@@ -34,15 +34,20 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport action for deleting an index template component
+ *
+ * @opensearch.internal
+ */
 public class DeleteComponentTemplateAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeleteComponentTemplateAction INSTANCE = new DeleteComponentTemplateAction();
@@ -52,7 +57,12 @@ private DeleteComponentTemplateAction() {
         super(NAME, AcknowledgedResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * Inner Request class for deleting component template
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String name;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateAction.java
index bc8b96f6259e8..496358cdfd2b1 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateAction.java
@@ -34,16 +34,21 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport action for deleting a composable index template
+ *
+ * @opensearch.internal
+ */
 public class DeleteComposableIndexTemplateAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeleteComposableIndexTemplateAction INSTANCE = new DeleteComposableIndexTemplateAction();
@@ -53,7 +58,12 @@ private DeleteComposableIndexTemplateAction() {
         super(NAME, AcknowledgedResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * Inner Request class for deleting composable index template
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String name;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateAction.java
index a91ec2850a107..789d03f8e8d8c 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for deleting an index template
+ *
+ * @opensearch.internal
+ */
 public class DeleteIndexTemplateAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeleteIndexTemplateAction INSTANCE = new DeleteIndexTemplateAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequest.java
index a3762bb62fb94..85524bddc56d8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequest.java
@@ -32,9 +32,9 @@
 package org.opensearch.action.admin.indices.template.delete;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -42,8 +42,10 @@
 
 /**
  * A request to delete an index template.
+ *
+ * @opensearch.internal
  */
-public class DeleteIndexTemplateRequest extends MasterNodeRequest<DeleteIndexTemplateRequest> {
+public class DeleteIndexTemplateRequest extends ClusterManagerNodeRequest<DeleteIndexTemplateRequest> {
 
     private String name;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequestBuilder.java
index b58cdd06da5e9..4a990b7837120 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/DeleteIndexTemplateRequestBuilder.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.action.admin.indices.template.delete;
 
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class DeleteIndexTemplateRequestBuilder extends MasterNodeOperationRequestBuilder<
+/**
+ * Transport request builder for deleting an index template
+ *
+ * @opensearch.internal
+ */
+public class DeleteIndexTemplateRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     DeleteIndexTemplateRequest,
     AcknowledgedResponse,
     DeleteIndexTemplateRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComponentTemplateAction.java
index 15ed0443525fb..30cb0cb3e5d00 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComponentTemplateAction.java
@@ -34,10 +34,9 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -45,13 +44,19 @@
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportDeleteComponentTemplateAction extends TransportMasterNodeAction<
+/**
+ * Transport action for deleting a component template
+ *
+ * @opensearch.internal
+ */
+public class TransportDeleteComponentTemplateAction extends TransportClusterManagerNodeAction<
     DeleteComponentTemplateAction.Request,
     AcknowledgedResponse> {
 
@@ -97,11 +102,11 @@ protected ClusterBlockException checkBlock(DeleteComponentTemplateAction.Request
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteComponentTemplateAction.Request request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
     ) {
-        indexTemplateService.removeComponentTemplate(request.name(), request.masterNodeTimeout(), listener);
+        indexTemplateService.removeComponentTemplate(request.name(), request.clusterManagerNodeTimeout(), listener);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComposableIndexTemplateAction.java
index 87b3a883a3c10..27ea64809e3a7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteComposableIndexTemplateAction.java
@@ -34,10 +34,9 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -45,13 +44,19 @@
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportDeleteComposableIndexTemplateAction extends TransportMasterNodeAction<
+/**
+ * Transport action for deleting a composable index template
+ *
+ * @opensearch.internal
+ */
+public class TransportDeleteComposableIndexTemplateAction extends TransportClusterManagerNodeAction<
     DeleteComposableIndexTemplateAction.Request,
     AcknowledgedResponse> {
 
@@ -97,11 +102,11 @@ protected ClusterBlockException checkBlock(DeleteComposableIndexTemplateAction.R
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteComposableIndexTemplateAction.Request request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
     ) {
-        indexTemplateService.removeIndexTemplateV2(request.name(), request.masterNodeTimeout(), listener);
+        indexTemplateService.removeIndexTemplateV2(request.name(), request.clusterManagerNodeTimeout(), listener);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteIndexTemplateAction.java
index e75d3aafe6a85..c9542c7a58810 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/TransportDeleteIndexTemplateAction.java
@@ -34,10 +34,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -45,7 +44,8 @@
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -53,8 +53,12 @@
 
 /**
  * Delete index action.
+ *
+ * @opensearch.internal
  */
-public class TransportDeleteIndexTemplateAction extends TransportMasterNodeAction<DeleteIndexTemplateRequest, AcknowledgedResponse> {
+public class TransportDeleteIndexTemplateAction extends TransportClusterManagerNodeAction<
+    DeleteIndexTemplateRequest,
+    AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportDeleteIndexTemplateAction.class);
 
@@ -98,13 +102,13 @@ protected ClusterBlockException checkBlock(DeleteIndexTemplateRequest request, C
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final DeleteIndexTemplateRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
     ) {
         indexTemplateService.removeTemplates(
-            new MetadataIndexTemplateService.RemoveRequest(request.name()).masterTimeout(request.masterNodeTimeout()),
+            new MetadataIndexTemplateService.RemoveRequest(request.name()).clusterManagerTimeout(request.clusterManagerNodeTimeout()),
             new MetadataIndexTemplateService.RemoveListener() {
                 @Override
                 public void onResponse(MetadataIndexTemplateService.RemoveResponse response) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/delete/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/package-info.java
new file mode 100644
index 0000000000000..f331c9dae4a38
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/delete/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Delete Index Templates transport handlers. */
+package org.opensearch.action.admin.indices.template.delete;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateAction.java
index 7f01ec0717332..51bd63c8473e6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateAction.java
@@ -33,16 +33,16 @@
 package org.opensearch.action.admin.indices.template.get;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.cluster.metadata.ComponentTemplate;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
@@ -50,6 +50,8 @@
 
 /**
  * Action to retrieve one or more component templates
+ *
+ * @opensearch.internal
  */
 public class GetComponentTemplateAction extends ActionType<GetComponentTemplateAction.Response> {
 
@@ -62,8 +64,10 @@ private GetComponentTemplateAction() {
 
     /**
      * Request that to retrieve one or more component templates
+     *
+     * @opensearch.internal
      */
-    public static class Request extends MasterNodeReadRequest<Request> {
+    public static class Request extends ClusterManagerNodeReadRequest<Request> {
 
         @Nullable
         private String name;
@@ -106,6 +110,11 @@ public String name() {
         }
     }
 
+    /**
+     * Inner response for getting component template
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse implements ToXContentObject {
         public static final ParseField NAME = new ParseField("name");
         public static final ParseField COMPONENT_TEMPLATES = new ParseField("component_templates");
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java
index 5f7ccb0b4f90f..0fdb08285e8b5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java
@@ -33,21 +33,26 @@
 package org.opensearch.action.admin.indices.template.get;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Action to retrieve one or more Composable Index templates
+ *
+ * @opensearch.internal
+ */
 public class GetComposableIndexTemplateAction extends ActionType<GetComposableIndexTemplateAction.Response> {
 
     public static final GetComposableIndexTemplateAction INSTANCE = new GetComposableIndexTemplateAction();
@@ -59,8 +64,10 @@ private GetComposableIndexTemplateAction() {
 
     /**
      * Request that to retrieve one or more index templates
+     *
+     * @opensearch.internal
      */
-    public static class Request extends MasterNodeReadRequest<Request> {
+    public static class Request extends ClusterManagerNodeReadRequest<Request> {
 
         @Nullable
         private String name;
@@ -120,6 +127,11 @@ public boolean equals(Object obj) {
         }
     }
 
+    /**
+     * Inner response for getting composable index template
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse implements ToXContentObject {
         public static final ParseField NAME = new ParseField("name");
         public static final ParseField INDEX_TEMPLATES = new ParseField("index_templates");
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesAction.java
index 1194abbab1cbb..f380ad6fddb55 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesAction.java
@@ -33,6 +33,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action to retrieve one or more Index templates
+ *
+ * @opensearch.internal
+ */
 public class GetIndexTemplatesAction extends ActionType<GetIndexTemplatesResponse> {
 
     public static final GetIndexTemplatesAction INSTANCE = new GetIndexTemplatesAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequest.java
index da48bc4d8bc29..18142eb7b787d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequest.java
@@ -32,10 +32,10 @@
 package org.opensearch.action.admin.indices.template.get;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -43,8 +43,10 @@
 
 /**
  * Request that allows to retrieve index templates
+ *
+ * @opensearch.internal
  */
-public class GetIndexTemplatesRequest extends MasterNodeReadRequest<GetIndexTemplatesRequest> {
+public class GetIndexTemplatesRequest extends ClusterManagerNodeReadRequest<GetIndexTemplatesRequest> {
 
     private String[] names;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequestBuilder.java
index 348075d051616..09de1733239fc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesRequestBuilder.java
@@ -31,10 +31,15 @@
 
 package org.opensearch.action.admin.indices.template.get;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class GetIndexTemplatesRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Request builder to retrieve one or more Index templates
+ *
+ * @opensearch.internal
+ */
+public class GetIndexTemplatesRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     GetIndexTemplatesRequest,
     GetIndexTemplatesResponse,
     GetIndexTemplatesRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponse.java
index e6d487e0a40b3..761a345b49538 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponse.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.action.admin.indices.template.get;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -46,6 +46,11 @@
 
 import static java.util.Collections.singletonMap;
 
+/**
+ * Response for retrieving one or more Index templates
+ *
+ * @opensearch.internal
+ */
 public class GetIndexTemplatesResponse extends ActionResponse implements ToXContentObject {
 
     private final List<IndexTemplateMetadata> indexTemplates;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComponentTemplateAction.java
index 62615465fbb4a..e2594cd792cd3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComponentTemplateAction.java
@@ -33,9 +33,8 @@
 package org.opensearch.action.admin.indices.template.get;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -43,8 +42,9 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -52,7 +52,12 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class TransportGetComponentTemplateAction extends TransportMasterNodeReadAction<
+/**
+ * Action to retrieve one or more Component templates
+ *
+ * @opensearch.internal
+ */
+public class TransportGetComponentTemplateAction extends TransportClusterManagerNodeReadAction<
     GetComponentTemplateAction.Request,
     GetComponentTemplateAction.Response> {
 
@@ -91,7 +96,7 @@ protected ClusterBlockException checkBlock(GetComponentTemplateAction.Request re
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         GetComponentTemplateAction.Request request,
         ClusterState state,
         ActionListener<GetComponentTemplateAction.Response> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComposableIndexTemplateAction.java
index efa6d4723ce0d..b1ef32db7274f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetComposableIndexTemplateAction.java
@@ -33,9 +33,8 @@
 package org.opensearch.action.admin.indices.template.get;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -43,8 +42,9 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -52,7 +52,12 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class TransportGetComposableIndexTemplateAction extends TransportMasterNodeReadAction<
+/**
+ * Transport Action to retrieve one or more Composable Index templates
+ *
+ * @opensearch.internal
+ */
+public class TransportGetComposableIndexTemplateAction extends TransportClusterManagerNodeReadAction<
     GetComposableIndexTemplateAction.Request,
     GetComposableIndexTemplateAction.Response> {
 
@@ -91,7 +96,7 @@ protected ClusterBlockException checkBlock(GetComposableIndexTemplateAction.Requ
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         GetComposableIndexTemplateAction.Request request,
         ClusterState state,
         ActionListener<GetComposableIndexTemplateAction.Response> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetIndexTemplatesAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetIndexTemplatesAction.java
index df6531d0a3862..10b4975f7b9d0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetIndexTemplatesAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/TransportGetIndexTemplatesAction.java
@@ -31,10 +31,8 @@
 
 package org.opensearch.action.admin.indices.template.get;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -42,8 +40,9 @@
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -51,8 +50,16 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 
-public class TransportGetIndexTemplatesAction extends TransportMasterNodeReadAction<GetIndexTemplatesRequest, GetIndexTemplatesResponse> {
+/**
+ * Transport action to retrieve one or more Index templates
+ *
+ * @opensearch.internal
+ */
+public class TransportGetIndexTemplatesAction extends TransportClusterManagerNodeReadAction<
+    GetIndexTemplatesRequest,
+    GetIndexTemplatesResponse> {
 
     @Inject
     public TransportGetIndexTemplatesAction(
@@ -89,7 +96,7 @@ protected ClusterBlockException checkBlock(GetIndexTemplatesRequest request, Clu
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         GetIndexTemplatesRequest request,
         ClusterState state,
         ActionListener<GetIndexTemplatesResponse> listener
@@ -98,16 +105,16 @@ protected void masterOperation(
 
         // If we did not ask for a specific name, then we return all templates
         if (request.names().length == 0) {
-            results = Arrays.asList(state.metadata().templates().values().toArray(IndexTemplateMetadata.class));
+            results = Arrays.asList(state.metadata().templates().values().toArray(new IndexTemplateMetadata[0]));
         } else {
             results = new ArrayList<>();
         }
 
         for (String name : request.names()) {
             if (Regex.isSimpleMatchPattern(name)) {
-                for (ObjectObjectCursor<String, IndexTemplateMetadata> entry : state.metadata().templates()) {
-                    if (Regex.simpleMatch(name, entry.key)) {
-                        results.add(entry.value);
+                for (final Map.Entry<String, IndexTemplateMetadata> entry : state.metadata().templates().entrySet()) {
+                    if (Regex.simpleMatch(name, entry.getKey())) {
+                        results.add(entry.getValue());
                     }
                 }
             } else if (state.metadata().templates().containsKey(name)) {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/template/get/package-info.java
new file mode 100644
index 0000000000000..e7173f4d6caaa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Index Templates transport handlers. */
+package org.opensearch.action.admin.indices.template.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/template/package-info.java
new file mode 100644
index 0000000000000..066a63f079232
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Index Templates transport handlers. */
+package org.opensearch.action.admin.indices.template;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateAction.java
index 3e6a586638e58..66b15c8b807f8 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateAction.java
@@ -34,6 +34,12 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport Action for handling simulating an index template either by name (looking it up in the
+ * cluster state), or by a provided template configuration
+ *
+ * @opensearch.internal
+ */
 public class SimulateIndexTemplateAction extends ActionType<SimulateIndexTemplateResponse> {
 
     public static final SimulateIndexTemplateAction INSTANCE = new SimulateIndexTemplateAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequest.java
index 9d6735751ac7e..028275778538e 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequest.java
@@ -34,16 +34,22 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
-public class SimulateIndexTemplateRequest extends MasterNodeReadRequest<SimulateIndexTemplateRequest> {
+/**
+ * Transport Request for handling simulating an index template either by name (looking it up in the
+ * cluster state), or by a provided template configuration
+ *
+ * @opensearch.internal
+ */
+public class SimulateIndexTemplateRequest extends ClusterManagerNodeReadRequest<SimulateIndexTemplateRequest> {
 
     private String indexName;
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateResponse.java
index 9116db02459ef..8a370a6845db6 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateResponse.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.action.admin.indices.template.post;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -49,6 +49,8 @@
 
 /**
  * Contains the information on what V2 templates would match a given index.
+ *
+ * @opensearch.internal
  */
 public class SimulateIndexTemplateResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateAction.java
index f53925e8abd50..0055676a7051a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateAction.java
@@ -36,10 +36,10 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -47,6 +47,8 @@
 /**
  * An action for simulating the complete composed settings of the specified
  * index template name, or index template configuration
+ *
+ * @opensearch.internal
  */
 public class SimulateTemplateAction extends ActionType<SimulateIndexTemplateResponse> {
 
@@ -57,7 +59,12 @@ private SimulateTemplateAction() {
         super(NAME, SimulateIndexTemplateResponse::new);
     }
 
-    public static class Request extends MasterNodeReadRequest<Request> {
+    /**
+     * Request for simulating a template action
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeReadRequest<Request> {
 
         @Nullable
         private String templateName;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java
index 598b5bdbf6d3b..c1a02d813ffb2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java
@@ -33,9 +33,8 @@
 package org.opensearch.action.admin.indices.template.post;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -52,9 +51,10 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.IndicesService;
@@ -75,7 +75,13 @@
 import static org.opensearch.cluster.metadata.MetadataIndexTemplateService.findV2Template;
 import static org.opensearch.cluster.metadata.MetadataIndexTemplateService.resolveSettings;
 
-public class TransportSimulateIndexTemplateAction extends TransportMasterNodeReadAction<
+/**
+ * Transport Action for handling simulating an index template either by name (looking it up in the
+ * cluster state), or by a provided template configuration
+ *
+ * @opensearch.internal
+ */
+public class TransportSimulateIndexTemplateAction extends TransportClusterManagerNodeReadAction<
     SimulateIndexTemplateRequest,
     SimulateIndexTemplateResponse> {
 
@@ -121,7 +127,7 @@ protected SimulateIndexTemplateResponse read(StreamInput in) throws IOException
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         SimulateIndexTemplateRequest request,
         ClusterState state,
         ActionListener<SimulateIndexTemplateResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateTemplateAction.java
index e12544a02be4c..6565896fd3db2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/TransportSimulateTemplateAction.java
@@ -32,22 +32,22 @@
 
 package org.opensearch.action.admin.indices.template.post;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.AliasValidator;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -64,8 +64,10 @@
 /**
  * Handles simulating an index template either by name (looking it up in the
  * cluster state), or by a provided template configuration
+ *
+ * @opensearch.internal
  */
-public class TransportSimulateTemplateAction extends TransportMasterNodeReadAction<
+public class TransportSimulateTemplateAction extends TransportClusterManagerNodeReadAction<
     SimulateTemplateAction.Request,
     SimulateIndexTemplateResponse> {
 
@@ -111,7 +113,7 @@ protected SimulateIndexTemplateResponse read(StreamInput in) throws IOException
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         SimulateTemplateAction.Request request,
         ClusterState state,
         ActionListener<SimulateIndexTemplateResponse> listener
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/post/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/template/post/package-info.java
new file mode 100644
index 0000000000000..60b5a1d2abce8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/post/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Post Index Templates transport handlers. */
+package org.opensearch.action.admin.indices.template.post;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComponentTemplateAction.java
index 69149b953cc08..d12f99ec345d3 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComponentTemplateAction.java
@@ -34,13 +34,13 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
 import org.opensearch.cluster.metadata.ComponentTemplate;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -48,6 +48,8 @@
 
 /**
  * An action for putting a single component template into the cluster state
+ *
+ * @opensearch.internal
  */
 public class PutComponentTemplateAction extends ActionType<AcknowledgedResponse> {
 
@@ -60,8 +62,10 @@ private PutComponentTemplateAction() {
 
     /**
      * A request for putting a single component template into the cluster state
+     *
+     * @opensearch.internal
      */
-    public static class Request extends MasterNodeRequest<Request> {
+    public static class Request extends ClusterManagerNodeRequest<Request> {
         private final String name;
         @Nullable
         private String cause;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateAction.java
index 059f3be745bb0..1979cc39e32fb 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateAction.java
@@ -36,21 +36,26 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * An action for putting a composable template into the cluster state
+ *
+ * @opensearch.internal
+ */
 public class PutComposableIndexTemplateAction extends ActionType<AcknowledgedResponse> {
 
     public static final PutComposableIndexTemplateAction INSTANCE = new PutComposableIndexTemplateAction();
@@ -62,8 +67,10 @@ private PutComposableIndexTemplateAction() {
 
     /**
      * A request for putting a single index template into the cluster state
+     *
+     * @opensearch.internal
      */
-    public static class Request extends MasterNodeRequest<Request> implements IndicesRequest {
+    public static class Request extends ClusterManagerNodeRequest<Request> implements IndicesRequest {
         private final String name;
         @Nullable
         private String cause;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateAction.java
index e3c072908596f..06a9f6fbba409 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * An action for putting an index template into the cluster state
+ *
+ * @opensearch.internal
+ */
 public class PutIndexTemplateAction extends ActionType<AcknowledgedResponse> {
 
     public static final PutIndexTemplateAction INSTANCE = new PutIndexTemplateAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
index 608e3da699318..013e66b2292a0 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
@@ -39,26 +39,26 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -77,8 +77,13 @@
 
 /**
  * A request to create an index template.
+ *
+ * @opensearch.internal
  */
-public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateRequest> implements IndicesRequest, ToXContentObject {
+public class PutIndexTemplateRequest extends ClusterManagerNodeRequest<PutIndexTemplateRequest>
+    implements
+        IndicesRequest,
+        ToXContentObject {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(PutIndexTemplateRequest.class);
 
@@ -220,8 +225,8 @@ public PutIndexTemplateRequest settings(Settings.Builder settings) {
     /**
      * The settings to create the index template with (either json/yaml format).
      */
-    public PutIndexTemplateRequest settings(String source, XContentType xContentType) {
-        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+    public PutIndexTemplateRequest settings(String source, MediaType mediaType) {
+        this.settings = Settings.builder().loadFromSource(source, mediaType).build();
         return this;
     }
 
@@ -253,10 +258,10 @@ public String cause() {
      * Adds mapping that will be added when the index gets created.
      *
      * @param source The mapping source
-     * @param xContentType The type of content contained within the source
+     * @param mediaType The type of content contained within the source
      */
-    public PutIndexTemplateRequest mapping(String source, XContentType xContentType) {
-        return mapping(new BytesArray(source), xContentType);
+    public PutIndexTemplateRequest mapping(String source, MediaType mediaType) {
+        return mapping(new BytesArray(source), mediaType);
     }
 
     /**
@@ -272,11 +277,11 @@ public PutIndexTemplateRequest mapping(XContentBuilder source) {
      * Adds mapping that will be added when the index gets created.
      *
      * @param source The mapping source
-     * @param xContentType the source content type
+     * @param mediaType the source content type
      */
-    public PutIndexTemplateRequest mapping(BytesReference source, XContentType xContentType) {
-        Objects.requireNonNull(xContentType);
-        Map<String, Object> mappingAsMap = XContentHelper.convertToMap(source, false, xContentType).v2();
+    public PutIndexTemplateRequest mapping(BytesReference source, MediaType mediaType) {
+        Objects.requireNonNull(mediaType);
+        Map<String, Object> mappingAsMap = XContentHelper.convertToMap(source, false, mediaType).v2();
         return mapping(mappingAsMap);
     }
 
@@ -292,7 +297,7 @@ public PutIndexTemplateRequest mapping(Map<String, Object> source) {
         try {
             XContentBuilder builder = XContentFactory.jsonBuilder();
             builder.map(source);
-            mappings = Strings.toString(builder);
+            mappings = builder.toString();
             return this;
         } catch (IOException e) {
             throw new OpenSearchGenerationException("Failed to generate [" + source + "]", e);
@@ -392,22 +397,22 @@ public PutIndexTemplateRequest source(String templateSource, XContentType xConte
     /**
      * The template source definition.
      */
-    public PutIndexTemplateRequest source(byte[] source, XContentType xContentType) {
-        return source(source, 0, source.length, xContentType);
+    public PutIndexTemplateRequest source(byte[] source, MediaType mediaType) {
+        return source(source, 0, source.length, mediaType);
     }
 
     /**
      * The template source definition.
      */
-    public PutIndexTemplateRequest source(byte[] source, int offset, int length, XContentType xContentType) {
-        return source(new BytesArray(source, offset, length), xContentType);
+    public PutIndexTemplateRequest source(byte[] source, int offset, int length, MediaType mediaType) {
+        return source(new BytesArray(source, offset, length), mediaType);
     }
 
     /**
      * The template source definition.
      */
-    public PutIndexTemplateRequest source(BytesReference source, XContentType xContentType) {
-        return source(XContentHelper.convertToMap(source, true, xContentType).v2());
+    public PutIndexTemplateRequest source(BytesReference source, MediaType mediaType) {
+        return source(XContentHelper.convertToMap(source, true, mediaType).v2());
     }
 
     public Set<Alias> aliases() {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
index e5a02acb4a6e9..04d2236e00e8f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
@@ -32,18 +32,24 @@
 package org.opensearch.action.admin.indices.template.put;
 
 import org.opensearch.action.admin.indices.alias.Alias;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.util.List;
 import java.util.Map;
 
-public class PutIndexTemplateRequestBuilder extends MasterNodeOperationRequestBuilder<
+/**
+ * A request builder for putting an index template into the cluster state
+ *
+ * @opensearch.internal
+ */
+public class PutIndexTemplateRequestBuilder extends ClusterManagerNodeOperationRequestBuilder<
     PutIndexTemplateRequest,
     AcknowledgedResponse,
     PutIndexTemplateRequestBuilder> {
@@ -108,8 +114,8 @@ public PutIndexTemplateRequestBuilder setSettings(Settings.Builder settings) {
     /**
      * The settings to crete the index template with (either json or yaml format)
      */
-    public PutIndexTemplateRequestBuilder setSettings(String source, XContentType xContentType) {
-        request.settings(source, xContentType);
+    public PutIndexTemplateRequestBuilder setSettings(String source, MediaType mediaType) {
+        request.settings(source, mediaType);
         return this;
     }
 
@@ -125,10 +131,10 @@ public PutIndexTemplateRequestBuilder setSettings(Map<String, Object> source) {
      * Adds mapping that will be added when the index template gets created.
      *
      * @param source The mapping source
-     * @param xContentType The type/format of the source
+     * @param mediaType The type/format of the source
      */
-    public PutIndexTemplateRequestBuilder setMapping(String source, XContentType xContentType) {
-        request.mapping(source, xContentType);
+    public PutIndexTemplateRequestBuilder setMapping(String source, MediaType mediaType) {
+        request.mapping(source, mediaType);
         return this;
     }
 
@@ -221,16 +227,16 @@ public PutIndexTemplateRequestBuilder setSource(Map<String, Object> templateSour
     /**
      * The template source definition.
      */
-    public PutIndexTemplateRequestBuilder setSource(BytesReference templateSource, XContentType xContentType) {
-        request.source(templateSource, xContentType);
+    public PutIndexTemplateRequestBuilder setSource(BytesReference templateSource, MediaType mediaType) {
+        request.source(templateSource, mediaType);
         return this;
     }
 
     /**
      * The template source definition.
      */
-    public PutIndexTemplateRequestBuilder setSource(byte[] templateSource, XContentType xContentType) {
-        request.source(templateSource, xContentType);
+    public PutIndexTemplateRequestBuilder setSource(byte[] templateSource, MediaType mediaType) {
+        request.source(templateSource, mediaType);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java
index 022ffbeb7e03a..6eb87bee9ffa7 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.action.admin.indices.template.put;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -46,15 +45,21 @@
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportPutComponentTemplateAction extends TransportMasterNodeAction<
+/**
+ * An action for putting a single component template into the cluster state
+ *
+ * @opensearch.internal
+ */
+public class TransportPutComponentTemplateAction extends TransportClusterManagerNodeAction<
     PutComponentTemplateAction.Request,
     AcknowledgedResponse> {
 
@@ -101,7 +106,7 @@ protected ClusterBlockException checkBlock(PutComponentTemplateAction.Request re
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutComponentTemplateAction.Request request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -120,7 +125,7 @@ protected void masterOperation(
             request.cause(),
             request.create(),
             request.name(),
-            request.masterNodeTimeout(),
+            request.clusterManagerNodeTimeout(),
             componentTemplate,
             listener
         );
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComposableIndexTemplateAction.java
index 7739c66b4cbd4..8a31c36d723b4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutComposableIndexTemplateAction.java
@@ -32,25 +32,30 @@
 
 package org.opensearch.action.admin.indices.template.put;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportPutComposableIndexTemplateAction extends TransportMasterNodeAction<
+/**
+ * An action for putting a composable index template into the cluster state
+ *
+ * @opensearch.internal
+ */
+public class TransportPutComposableIndexTemplateAction extends TransportClusterManagerNodeAction<
     PutComposableIndexTemplateAction.Request,
     AcknowledgedResponse> {
 
@@ -94,7 +99,7 @@ protected ClusterBlockException checkBlock(PutComposableIndexTemplateAction.Requ
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutComposableIndexTemplateAction.Request request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -104,7 +109,7 @@ protected void masterOperation(
             request.cause(),
             request.create(),
             request.name(),
-            request.masterNodeTimeout(),
+            request.clusterManagerNodeTimeout(),
             indexTemplate,
             listener
         );
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutIndexTemplateAction.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutIndexTemplateAction.java
index 42d932c62da55..4431949c2e42b 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/TransportPutIndexTemplateAction.java
@@ -34,10 +34,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
@@ -46,9 +45,10 @@
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -56,8 +56,10 @@
 
 /**
  * Put index template action.
+ *
+ * @opensearch.internal
  */
-public class TransportPutIndexTemplateAction extends TransportMasterNodeAction<PutIndexTemplateRequest, AcknowledgedResponse> {
+public class TransportPutIndexTemplateAction extends TransportClusterManagerNodeAction<PutIndexTemplateRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportPutIndexTemplateAction.class);
 
@@ -104,7 +106,7 @@ protected ClusterBlockException checkBlock(PutIndexTemplateRequest request, Clus
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final PutIndexTemplateRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
@@ -123,7 +125,7 @@ protected void masterOperation(
                 .mappings(request.mappings())
                 .aliases(request.aliases())
                 .create(request.create())
-                .masterTimeout(request.masterNodeTimeout())
+                .clusterManagerTimeout(request.clusterManagerNodeTimeout())
                 .version(request.version()),
 
             new MetadataIndexTemplateService.PutListener() {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/template/put/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/template/put/package-info.java
new file mode 100644
index 0000000000000..a0033a434b7b3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/template/put/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Put Index Templates transport handlers. */
+package org.opensearch.action.admin.indices.template.put;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexShardUpgradeStatus.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexShardUpgradeStatus.java
index 954ab28542904..32cf6d4bfe70d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexShardUpgradeStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexShardUpgradeStatus.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.admin.indices.upgrade.get;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Arrays;
 import java.util.Iterator;
 
+/**
+ * Status for an Index Shard Upgrade
+ *
+ * @opensearch.internal
+ */
 public class IndexShardUpgradeStatus implements Iterable<ShardUpgradeStatus> {
 
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexUpgradeStatus.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexUpgradeStatus.java
index 19f97faff3c61..2cff1f04d3fd2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexUpgradeStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/IndexUpgradeStatus.java
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Status for an Index Upgrade
+ *
+ * @opensearch.internal
+ */
 public class IndexUpgradeStatus implements Iterable<IndexShardUpgradeStatus> {
 
     private final String index;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/ShardUpgradeStatus.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/ShardUpgradeStatus.java
index 579bd5e969eef..57fb2513faf78 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/ShardUpgradeStatus.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/ShardUpgradeStatus.java
@@ -34,11 +34,16 @@
 
 import org.opensearch.action.support.broadcast.BroadcastShardResponse;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Status for a Shard Upgrade
+ *
+ * @opensearch.internal
+ */
 public class ShardUpgradeStatus extends BroadcastShardResponse {
 
     private ShardRouting shardRouting;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/TransportUpgradeStatusAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/TransportUpgradeStatusAction.java
index fcad2ccc6298d..e3afa342a933a 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/TransportUpgradeStatusAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/TransportUpgradeStatusAction.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.Version;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -44,7 +43,8 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Segment;
 import org.opensearch.index.shard.IndexShard;
@@ -55,6 +55,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport Action for Upgrading an Index
+ *
+ * @opensearch.internal
+ */
 public class TransportUpgradeStatusAction extends TransportBroadcastByNodeAction<
     UpgradeStatusRequest,
     UpgradeStatusResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusAction.java
index 7612bcb4464d4..a43d7580a571f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action for Upgrading an Index
+ *
+ * @opensearch.internal
+ */
 public class UpgradeStatusAction extends ActionType<UpgradeStatusResponse> {
 
     public static final UpgradeStatusAction INSTANCE = new UpgradeStatusAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequest.java
index bc7f0f31a6197..987661d2129ac 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequest.java
@@ -33,11 +33,16 @@
 package org.opensearch.action.admin.indices.upgrade.get;
 
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport Request for retrieving status of upgrading an Index
+ *
+ * @opensearch.internal
+ */
 public class UpgradeStatusRequest extends BroadcastRequest<UpgradeStatusRequest> {
 
     public UpgradeStatusRequest() {
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequestBuilder.java
index 6f4f601a81d8a..c698c38fe12d5 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.support.broadcast.BroadcastOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport Request Builder for retrieving status of upgrading an Index
+ *
+ * @opensearch.internal
+ */
 public class UpgradeStatusRequestBuilder extends BroadcastOperationRequestBuilder<
     UpgradeStatusRequest,
     UpgradeStatusResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusResponse.java
index a8bb5cfc8bba1..575e5ccfde027 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/UpgradeStatusResponse.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.action.admin.indices.upgrade.get;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,6 +47,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Transport Response for retrieving status of upgrading an Index
+ *
+ * @opensearch.internal
+ */
 public class UpgradeStatusResponse extends BroadcastResponse {
     private ShardUpgradeStatus[] shards;
 
@@ -200,6 +205,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String INDICES = "indices";
         static final String SHARDS = "shards";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/package-info.java
new file mode 100644
index 0000000000000..58ad55e715d94
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Get Upgrade Indices transport handlers. */
+package org.opensearch.action.admin.indices.upgrade.get;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/package-info.java
new file mode 100644
index 0000000000000..ee5633c39fc2f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Upgrade Indices transport handlers. */
+package org.opensearch.action.admin.indices.upgrade;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeRequest.java
deleted file mode 100644
index fcc85e1a9cb5c..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeRequest.java
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.upgrade.post;
-
-import org.opensearch.action.support.broadcast.BroadcastShardRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
-
-import java.io.IOException;
-
-public final class ShardUpgradeRequest extends BroadcastShardRequest {
-
-    private UpgradeRequest request;
-
-    public ShardUpgradeRequest(StreamInput in) throws IOException {
-        super(in);
-        request = new UpgradeRequest(in);
-    }
-
-    ShardUpgradeRequest(ShardId shardId, UpgradeRequest request) {
-        super(shardId, request);
-        this.request = request;
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        request.writeTo(out);
-    }
-
-    public UpgradeRequest upgradeRequest() {
-        return this.request;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeResult.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeResult.java
index a4fcbaca55299..ebcb269725a6d 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeResult.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/ShardUpgradeResult.java
@@ -33,14 +33,19 @@
 package org.opensearch.action.admin.indices.upgrade.post;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.text.ParseException;
 
+/**
+ * Result for Upgrading a Shard
+ *
+ * @opensearch.internal
+ */
 class ShardUpgradeResult implements Writeable {
 
     private ShardId shardId;
@@ -61,7 +66,7 @@ class ShardUpgradeResult implements Writeable {
     ShardUpgradeResult(StreamInput in) throws IOException {
         shardId = new ShardId(in);
         primary = in.readBoolean();
-        upgradeVersion = Version.readVersion(in);
+        upgradeVersion = in.readVersion();
         try {
             oldestLuceneSegment = org.apache.lucene.util.Version.parse(in.readString());
         } catch (ParseException ex) {
@@ -89,7 +94,7 @@ public boolean primary() {
     public void writeTo(StreamOutput out) throws IOException {
         shardId.writeTo(out);
         out.writeBoolean(primary);
-        Version.writeVersion(upgradeVersion, out);
+        out.writeVersion(upgradeVersion);
         out.writeString(oldestLuceneSegment.toString());
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeAction.java
index 1048de90b214e..2dcd030093a67 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeAction.java
@@ -33,10 +33,8 @@
 package org.opensearch.action.admin.indices.upgrade.post;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.PrimaryMissingActionException;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterState;
@@ -51,7 +49,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
@@ -67,6 +67,8 @@
 
 /**
  * Upgrade index/indices action.
+ *
+ * @opensearch.internal
  */
 public class TransportUpgradeAction extends TransportBroadcastByNodeAction<UpgradeRequest, UpgradeResponse, ShardUpgradeResult> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeSettingsAction.java
index cacd341730e12..286724d78bb63 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/TransportUpgradeSettingsAction.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -47,13 +46,19 @@
 import org.opensearch.cluster.metadata.MetadataUpdateSettingsService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class TransportUpgradeSettingsAction extends TransportMasterNodeAction<UpgradeSettingsRequest, AcknowledgedResponse> {
+/**
+ * Transport action for upgrading index settings
+ *
+ * @opensearch.internal
+ */
+public class TransportUpgradeSettingsAction extends TransportClusterManagerNodeAction<UpgradeSettingsRequest, AcknowledgedResponse> {
 
     private static final Logger logger = LogManager.getLogger(TransportUpgradeSettingsAction.class);
 
@@ -97,14 +102,14 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(
+    protected void clusterManagerOperation(
         final UpgradeSettingsRequest request,
         final ClusterState state,
         final ActionListener<AcknowledgedResponse> listener
     ) {
         UpgradeSettingsClusterStateUpdateRequest clusterStateUpdateRequest = new UpgradeSettingsClusterStateUpdateRequest().ackTimeout(
             request.timeout()
-        ).versions(request.versions()).masterNodeTimeout(request.masterNodeTimeout());
+        ).versions(request.versions()).masterNodeTimeout(request.clusterManagerNodeTimeout());
 
         updateSettingsService.upgradeIndexSettings(clusterStateUpdateRequest, new ActionListener<ClusterStateUpdateResponse>() {
             @Override
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeAction.java
index ee9da454ad141..369503bb54ecf 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Upgrade index/indices action.
+ *
+ * @opensearch.internal
  */
 public class UpgradeAction extends ActionType<UpgradeResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequest.java
index 94d07075a8f3e..98c307c37ea54 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequest.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.admin.indices.upgrade.post;
 
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
@@ -44,9 +44,16 @@
  * @see org.opensearch.client.Requests#upgradeRequest(String...)
  * @see org.opensearch.client.IndicesAdminClient#upgrade(UpgradeRequest)
  * @see UpgradeResponse
+ *
+ * @opensearch.internal
  */
 public class UpgradeRequest extends BroadcastRequest<UpgradeRequest> {
 
+    /**
+     * Default config for Upgrade Requests
+     *
+     * @opensearch.internal
+     */
     public static final class Defaults {
         public static final boolean UPGRADE_ONLY_ANCIENT_SEGMENTS = false;
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequestBuilder.java
index 5deff45aadc9b..8203f9d51b8e4 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeRequestBuilder.java
@@ -38,6 +38,8 @@
 /**
  * A request to upgrade one or more indices. In order to optimize on all the indices, pass an empty array or
  * {@code null} for the indices.
+ *
+ * @opensearch.internal
  */
 public class UpgradeRequestBuilder extends BroadcastOperationRequestBuilder<UpgradeRequest, UpgradeResponse, UpgradeRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeResponse.java
index 07f9debbbf97b..d08cc65832f8f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeResponse.java
@@ -33,12 +33,12 @@
 package org.opensearch.action.admin.indices.upgrade.post;
 
 import org.opensearch.Version;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -47,7 +47,7 @@
 /**
  * A response for the upgrade action.
  *
- *
+ * @opensearch.internal
  */
 public class UpgradeResponse extends BroadcastResponse {
 
@@ -55,7 +55,7 @@ public class UpgradeResponse extends BroadcastResponse {
 
     UpgradeResponse(StreamInput in) throws IOException {
         super(in);
-        versions = in.readMap(StreamInput::readString, i -> Tuple.tuple(Version.readVersion(i), i.readString()));
+        versions = in.readMap(StreamInput::readString, i -> Tuple.tuple(i.readVersion(), i.readString()));
     }
 
     UpgradeResponse(
@@ -73,7 +73,7 @@ public class UpgradeResponse extends BroadcastResponse {
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeMap(versions, StreamOutput::writeString, (o, v) -> {
-            Version.writeVersion(v.v1(), o);
+            o.writeVersion(v.v1());
             o.writeString(v.v2());
         });
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsAction.java
index f9ecc9ace9171..05944e781d109 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action for upgrading index settings
+ *
+ * @opensearch.internal
+ */
 public class UpgradeSettingsAction extends ActionType<AcknowledgedResponse> {
 
     public static final UpgradeSettingsAction INSTANCE = new UpgradeSettingsAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsClusterStateUpdateRequest.java
index cf24e20a44ee3..ee6c6161713ac 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsClusterStateUpdateRequest.java
@@ -40,6 +40,8 @@
 
 /**
  * Cluster state update request that allows to change minimum compatibility settings for some indices
+ *
+ * @opensearch.internal
  */
 public class UpgradeSettingsClusterStateUpdateRequest extends ClusterStateUpdateRequest<UpgradeSettingsClusterStateUpdateRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequest.java
index dc3a60c62033b..306d29dd84f13 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequest.java
@@ -36,8 +36,8 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Map;
@@ -46,6 +46,8 @@
 
 /**
  * Request for an update index settings action
+ *
+ * @opensearch.internal
  */
 public class UpgradeSettingsRequest extends AcknowledgedRequest<UpgradeSettingsRequest> {
 
@@ -53,7 +55,7 @@ public class UpgradeSettingsRequest extends AcknowledgedRequest<UpgradeSettingsR
 
     public UpgradeSettingsRequest(StreamInput in) throws IOException {
         super(in);
-        versions = in.readMap(StreamInput::readString, i -> new Tuple<>(Version.readVersion(i), i.readString()));
+        versions = in.readMap(StreamInput::readString, i -> new Tuple<>(i.readVersion(), i.readString()));
     }
 
     public UpgradeSettingsRequest() {}
@@ -92,7 +94,7 @@ public UpgradeSettingsRequest versions(Map<String, Tuple<Version, String>> versi
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeMap(versions, StreamOutput::writeString, (o, v) -> {
-            Version.writeVersion(v.v1(), out);
+            out.writeVersion(v.v1());
             out.writeString(v.v2());
         });
     }
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequestBuilder.java
deleted file mode 100644
index d3a8cc311bb8a..0000000000000
--- a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/UpgradeSettingsRequestBuilder.java
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.admin.indices.upgrade.post;
-
-import org.opensearch.Version;
-import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
-import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.collect.Tuple;
-
-import java.util.Map;
-
-/**
- * Builder for an update index settings request
- */
-public class UpgradeSettingsRequestBuilder extends AcknowledgedRequestBuilder<
-    UpgradeSettingsRequest,
-    AcknowledgedResponse,
-    UpgradeSettingsRequestBuilder> {
-
-    public UpgradeSettingsRequestBuilder(OpenSearchClient client, UpgradeSettingsAction action) {
-        super(client, action, new UpgradeSettingsRequest());
-    }
-
-    /**
-     * Sets the index versions to be updated
-     */
-    public UpgradeSettingsRequestBuilder setVersions(Map<String, Tuple<Version, String>> versions) {
-        request.versions(versions);
-        return this;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/package-info.java
new file mode 100644
index 0000000000000..ae8c8839acaba
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/upgrade/post/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Post Upgrade Indices transport handlers. */
+package org.opensearch.action.admin.indices.upgrade.post;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/package-info.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/package-info.java
new file mode 100644
index 0000000000000..ee210f7495e70
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Query Validation transport handlers. */
+package org.opensearch.action.admin.indices.validate;
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/QueryExplanation.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/QueryExplanation.java
index 3764cfd1e608b..248cab5e40eaf 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/QueryExplanation.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/QueryExplanation.java
@@ -32,21 +32,26 @@
 
 package org.opensearch.action.admin.indices.validate.query;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Query Explanation
+ *
+ * @opensearch.internal
+ */
 public class QueryExplanation implements Writeable, ToXContentFragment {
 
     public static final String INDEX_FIELD = "index";
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryRequest.java
index 4d6525d002381..fb6e78d3ca4fc 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryRequest.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.Version;
 import org.opensearch.action.support.broadcast.BroadcastShardRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.QueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.internal.AliasFilter;
 
 import java.io.IOException;
@@ -45,6 +45,8 @@
 
 /**
  * Internal validate request executed directly against a specific index shard.
+ *
+ * @opensearch.internal
  */
 public class ShardValidateQueryRequest extends BroadcastShardRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryResponse.java
index 88080bd7667f3..f72352cd8cd95 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ShardValidateQueryResponse.java
@@ -33,16 +33,16 @@
 package org.opensearch.action.admin.indices.validate.query;
 
 import org.opensearch.action.support.broadcast.BroadcastShardResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Internal validate response of a shard validate request executed directly against a specific shard.
  *
- *
+ * @opensearch.internal
  */
 class ShardValidateQueryResponse extends BroadcastShardResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryAction.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryAction.java
index 1849b41ce707f..2b46fbcb9d105 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryAction.java
@@ -34,9 +34,7 @@
 
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException;
 import org.opensearch.action.support.broadcast.TransportBroadcastAction;
 import org.opensearch.cluster.ClusterState;
@@ -46,11 +44,13 @@
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.query.ParsedQuery;
 import org.opensearch.index.query.QueryShardException;
@@ -72,6 +72,11 @@
 import java.util.concurrent.atomic.AtomicReferenceArray;
 import java.util.function.LongSupplier;
 
+/**
+ * Transport Action to Validate a Query
+ *
+ * @opensearch.internal
+ */
 public class TransportValidateQueryAction extends TransportBroadcastAction<
     ValidateQueryRequest,
     ValidateQueryResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryAction.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryAction.java
index a9b0954287c30..cdeb9e818a52f 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action to Validate a Query
+ *
+ * @opensearch.internal
+ */
 public class ValidateQueryAction extends ActionType<ValidateQueryResponse> {
 
     public static final ValidateQueryAction INSTANCE = new ValidateQueryAction();
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequest.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequest.java
index 1bb85c4e84483..ef0d14502af23 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequest.java
@@ -37,11 +37,11 @@
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 
@@ -52,6 +52,8 @@
  * A request to validate a specific query.
  * <p>
  * The request requires the query to be set using {@link #query(QueryBuilder)}
+ *
+ * @opensearch.internal
  */
 public class ValidateQueryRequest extends BroadcastRequest<ValidateQueryRequest> implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequestBuilder.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequestBuilder.java
index 88261e6536240..6209f41d88be2 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.index.query.QueryBuilder;
 
+/**
+ * Transport Request Builder to Validate a Query
+ *
+ * @opensearch.internal
+ */
 public class ValidateQueryRequestBuilder extends BroadcastOperationRequestBuilder<
     ValidateQueryRequest,
     ValidateQueryResponse,
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponse.java b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponse.java
index 53d1463c23351..44d6d637cdc51 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponse.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponse.java
@@ -32,27 +32,27 @@
 
 package org.opensearch.action.admin.indices.validate.query;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * The response of the validate action.
  *
- *
+ * @opensearch.internal
  */
 public class ValidateQueryResponse extends BroadcastResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/admin/package-info.java b/server/src/main/java/org/opensearch/action/admin/package-info.java
index 1ee6ebacef3a5..4be3b7cf12e9c 100644
--- a/server/src/main/java/org/opensearch/action/admin/package-info.java
+++ b/server/src/main/java/org/opensearch/action/admin/package-info.java
@@ -25,12 +25,12 @@
  * under the License.
  */
 
-/**
- * Administrative Actions.
- */
 /*
  * Modifications Copyright OpenSearch Contributors. See
  * GitHub history for details.
  */
 
+/**
+ * Administrative Actions.
+ */
 package org.opensearch.action.admin;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BackoffPolicy.java b/server/src/main/java/org/opensearch/action/bulk/BackoffPolicy.java
index 50acd82ae9002..0d6d122e31261 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BackoffPolicy.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BackoffPolicy.java
@@ -31,6 +31,7 @@
 
 package org.opensearch.action.bulk;
 
+import org.opensearch.common.Randomness;
 import org.opensearch.common.unit.TimeValue;
 
 import java.util.Iterator;
@@ -53,6 +54,8 @@
  * </ul>
  *
  * Note that backoff policies are exposed as <code>Iterables</code> in order to be consumed multiple times.
+ *
+ * @opensearch.internal
  */
 public abstract class BackoffPolicy implements Iterable<TimeValue> {
     private static final BackoffPolicy NO_BACKOFF = new NoBackoff();
@@ -103,6 +106,30 @@ public static BackoffPolicy exponentialBackoff(TimeValue initialDelay, int maxNu
         return new ExponentialBackoff((int) checkDelay(initialDelay).millis(), maxNumberOfRetries);
     }
 
+    /**
+     *  It provides exponential backoff between retries until it reaches maxDelayForRetry.
+     *  It uses equal jitter scheme as it is being used for throttled exceptions.
+     *  It will make random distribution and also guarantees a minimum delay.
+     *
+     * @param baseDelay BaseDelay for exponential Backoff
+     * @param maxDelayForRetry MaxDelay that can be returned from backoff policy
+     * @return A backoff policy with exponential backoff with equal jitter which can't return delay more than given max delay
+     */
+    public static BackoffPolicy exponentialEqualJitterBackoff(long baseDelay, long maxDelayForRetry) {
+        return new ExponentialEqualJitterBackoff(baseDelay, maxDelayForRetry);
+    }
+
+    /**
+     *  It provides exponential backoff between retries until it reaches Integer.MAX_VALUE.
+     *  It uses full jitter scheme for random distribution.
+     *
+     * @param baseDelay BaseDelay for exponential Backoff
+     * @return A backoff policy with exponential backoff with full jitter.
+     */
+    public static BackoffPolicy exponentialFullJitterBackoff(long baseDelay) {
+        return new ExponentialFullJitterBackoff(baseDelay);
+    }
+
     /**
      * Wraps the backoff policy in one that calls a method every time a new backoff is taken from the policy.
      */
@@ -117,6 +144,11 @@ private static TimeValue checkDelay(TimeValue delay) {
         return delay;
     }
 
+    /**
+     * Concrete No Back Off Policy
+     *
+     * @opensearch.internal
+     */
     private static class NoBackoff extends BackoffPolicy {
         @Override
         public Iterator<TimeValue> iterator() {
@@ -134,6 +166,11 @@ public TimeValue next() {
         }
     }
 
+    /**
+     * Concrete Exponential Back Off Policy
+     *
+     * @opensearch.internal
+     */
     private static class ExponentialBackoff extends BackoffPolicy {
         private final int start;
 
@@ -152,6 +189,11 @@ public Iterator<TimeValue> iterator() {
         }
     }
 
+    /**
+     * Concrete Exponential Back Off Iterator
+     *
+     * @opensearch.internal
+     */
     private static class ExponentialBackoffIterator implements Iterator<TimeValue> {
         private final int numberOfElements;
 
@@ -180,6 +222,112 @@ public TimeValue next() {
         }
     }
 
+    private static class ExponentialEqualJitterBackoff extends BackoffPolicy {
+        private final long maxDelayForRetry;
+        private final long baseDelay;
+
+        private ExponentialEqualJitterBackoff(long baseDelay, long maxDelayForRetry) {
+            this.maxDelayForRetry = maxDelayForRetry;
+            this.baseDelay = baseDelay;
+        }
+
+        @Override
+        public Iterator<TimeValue> iterator() {
+            return new ExponentialEqualJitterBackoffIterator(baseDelay, maxDelayForRetry);
+        }
+    }
+
+    private static class ExponentialEqualJitterBackoffIterator implements Iterator<TimeValue> {
+        /**
+         * Retry limit to avoids integer overflow issues.
+         * Post this limit, max delay will be returned with Equal Jitter.
+         *
+         * NOTE: If the value is greater than 30, there can be integer overflow
+         * issues during delay calculation.
+         **/
+        private final int RETRIES_TILL_JITTER_INCREASE = 30;
+
+        /**
+         * Exponential increase in delay will happen till it reaches maxDelayForRetry.
+         * Once delay has exceeded maxDelayForRetry, it will return maxDelayForRetry only
+         * and not increase the delay.
+         */
+        private final long maxDelayForRetry;
+        private final long baseDelay;
+        private int retriesAttempted;
+
+        private ExponentialEqualJitterBackoffIterator(long baseDelay, long maxDelayForRetry) {
+            this.baseDelay = baseDelay;
+            this.maxDelayForRetry = maxDelayForRetry;
+        }
+
+        /**
+         * There is not any limit for this BackOff.
+         * This Iterator will always return back off delay.
+         *
+         * @return true
+         */
+        @Override
+        public boolean hasNext() {
+            return true;
+        }
+
+        @Override
+        public TimeValue next() {
+            int retries = Math.min(retriesAttempted, RETRIES_TILL_JITTER_INCREASE);
+            int exponentialDelay = (int) Math.min((1L << retries) * baseDelay, maxDelayForRetry);
+            retriesAttempted++;
+            return TimeValue.timeValueMillis((exponentialDelay / 2) + Randomness.get().nextInt(exponentialDelay / 2 + 1));
+        }
+    }
+
+    private static class ExponentialFullJitterBackoff extends BackoffPolicy {
+        private final long baseDelay;
+
+        private ExponentialFullJitterBackoff(long baseDelay) {
+            this.baseDelay = baseDelay;
+        }
+
+        @Override
+        public Iterator<TimeValue> iterator() {
+            return new ExponentialFullJitterBackoffIterator(baseDelay);
+        }
+    }
+
+    private static class ExponentialFullJitterBackoffIterator implements Iterator<TimeValue> {
+        /**
+         * Current delay in exponential backoff
+         */
+        private long currentDelay;
+
+        private ExponentialFullJitterBackoffIterator(long baseDelay) {
+            this.currentDelay = baseDelay;
+        }
+
+        /**
+         * There is not any limit for this BackOff.
+         * This Iterator will always return back off delay.
+         *
+         * @return true
+         */
+        @Override
+        public boolean hasNext() {
+            return true;
+        }
+
+        @Override
+        public TimeValue next() {
+            TimeValue delayToReturn = TimeValue.timeValueMillis(Randomness.get().nextInt(Math.toIntExact(currentDelay)) + 1);
+            currentDelay = Math.min(2 * currentDelay, Integer.MAX_VALUE);
+            return delayToReturn;
+        }
+    }
+
+    /**
+     * Concrete Constant Back Off Policy
+     *
+     * @opensearch.internal
+     */
     private static final class ConstantBackoff extends BackoffPolicy {
         private final TimeValue delay;
 
@@ -197,6 +345,11 @@ public Iterator<TimeValue> iterator() {
         }
     }
 
+    /**
+     * Concrete Constant Back Off Iterator
+     *
+     * @opensearch.internal
+     */
     private static final class ConstantBackoffIterator implements Iterator<TimeValue> {
         private final TimeValue delay;
         private final int numberOfElements;
@@ -222,6 +375,11 @@ public TimeValue next() {
         }
     }
 
+    /**
+     * Concrete Wrapped Back Off Policy
+     *
+     * @opensearch.internal
+     */
     private static final class WrappedBackoffPolicy extends BackoffPolicy {
         private final BackoffPolicy delegate;
         private final Runnable onBackoff;
@@ -237,6 +395,11 @@ public Iterator<TimeValue> iterator() {
         }
     }
 
+    /**
+     * Concrete Wrapped Back Off Iterator
+     *
+     * @opensearch.internal
+     */
     private static final class WrappedBackoffIterator implements Iterator<TimeValue> {
         private final Iterator<TimeValue> delegate;
         private final Runnable onBackoff;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkAction.java b/server/src/main/java/org/opensearch/action/bulk/BulkAction.java
index 031c8efa8cb84..f80ec32628b8a 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkAction.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkAction.java
@@ -36,6 +36,11 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.transport.TransportRequestOptions;
 
+/**
+ * Transport action for bulk indexing
+ *
+ * @opensearch.internal
+ */
 public class BulkAction extends ActionType<BulkResponse> {
 
     public static final BulkAction INSTANCE = new BulkAction();
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkItemRequest.java b/server/src/main/java/org/opensearch/action/bulk/BulkItemRequest.java
index 2002d5864e966..79201e0f7b38f 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkItemRequest.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkItemRequest.java
@@ -36,15 +36,21 @@
 import org.apache.lucene.util.RamUsageEstimator;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport request for a Single bulk item
+ *
+ * @opensearch.internal
+ */
 public class BulkItemRequest implements Writeable, Accountable {
 
     private static final long SHALLOW_SIZE = RamUsageEstimator.shallowSizeOfInstance(BulkItemRequest.class);
@@ -109,7 +115,7 @@ public void abort(String index, Exception cause) {
             setPrimaryResponse(new BulkItemResponse(id, request.opType(), failure));
         } else {
             assert primaryResponse.isFailed() && primaryResponse.getFailure().isAborted() : "response ["
-                + Strings.toString(primaryResponse)
+                + Strings.toString(MediaTypeRegistry.JSON, primaryResponse)
                 + "]; cause ["
                 + cause
                 + "]";
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkItemResponse.java b/server/src/main/java/org/opensearch/action/bulk/BulkItemResponse.java
index fdb27a00bac2d..72e22f6b72019 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkItemResponse.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkItemResponse.java
@@ -42,31 +42,34 @@
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.throwUnknownField;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.throwUnknownField;
 
 /**
  * Represents a single item response for an action executed as part of the bulk API. Holds the index/type/id
  * of the relevant action, and if it has failed or not (with the failure message in case it failed).
+ *
+ * @opensearch.internal
  */
 public class BulkItemResponse implements Writeable, StatusToXContentObject {
 
@@ -176,6 +179,8 @@ public static BulkItemResponse fromXContent(XContentParser parser, int id) throw
 
     /**
      * Represents a failure.
+     *
+     * @opensearch.internal
      */
     public static class Failure implements Writeable, ToXContentFragment {
         public static final String INDEX_FIELD = "index";
@@ -370,7 +375,7 @@ public static Failure fromXContent(XContentParser parser) {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkPrimaryExecutionContext.java b/server/src/main/java/org/opensearch/action/bulk/BulkPrimaryExecutionContext.java
index da8833fe49a29..896456089ee3e 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkPrimaryExecutionContext.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkPrimaryExecutionContext.java
@@ -48,6 +48,8 @@
  * This is a utility class that holds the per request state needed to perform bulk operations on the primary.
  * More specifically, it maintains an index to the current executing bulk item, which allows execution
  * to stop and wait for external events such as mapping updates.
+ *
+ * @opensearch.internal
  */
 class BulkPrimaryExecutionContext {
 
@@ -61,7 +63,7 @@ enum ItemProcessingState {
         TRANSLATED,
         /**
          * the request can not execute with the current mapping and should wait for a new mapping
-         * to arrive from the master. A mapping request for the needed changes has already been
+         * to arrive from the cluster-manager. A mapping request for the needed changes has already been
          * submitted
          */
         WAIT_FOR_MAPPING_UPDATE,
@@ -144,7 +146,7 @@ public boolean isOperationExecuted() {
         return currentItemState == ItemProcessingState.EXECUTED;
     }
 
-    /** returns true if the request needs to wait for a mapping update to arrive from the master */
+    /** returns true if the request needs to wait for a mapping update to arrive from the cluster-manager */
     public boolean requiresWaitingForMappingUpdate() {
         return currentItemState == ItemProcessingState.WAIT_FOR_MAPPING_UPDATE;
     }
@@ -216,7 +218,7 @@ public <T extends DocWriteRequest<T>> T getRequestToExecute() {
         return (T) requestToExecute;
     }
 
-    /** indicates that the current operation can not be completed and needs to wait for a new mapping from the master */
+    /** indicates that the current operation can not be completed and needs to wait for a new mapping from the cluster-manager */
     public void markAsRequiringMappingUpdate() {
         assert assertInvariants(ItemProcessingState.TRANSLATED);
         currentItemState = ItemProcessingState.WAIT_FOR_MAPPING_UPDATE;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkProcessor.java b/server/src/main/java/org/opensearch/action/bulk/BulkProcessor.java
index 90a177119cfd8..baf64b3e80af6 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkProcessor.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkProcessor.java
@@ -32,19 +32,20 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.client.Client;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -63,6 +64,8 @@
  * requests allowed to be executed in parallel.
  * <p>
  * In order to create a new bulk processor, use the {@link Builder}.
+ *
+ * @opensearch.internal
  */
 public class BulkProcessor implements Closeable {
 
@@ -92,6 +95,8 @@ public interface Listener {
 
     /**
      * A builder used to create a build an instance of a bulk processor.
+     *
+     * @opensearch.internal
      */
     public static class Builder {
 
@@ -453,17 +458,13 @@ public BulkProcessor add(BytesReference data, @Nullable String defaultIndex, XCo
     /**
      * Adds the data from the bytes to be processed by the bulk processor
      */
-    public BulkProcessor add(
-        BytesReference data,
-        @Nullable String defaultIndex,
-        @Nullable String defaultPipeline,
-        XContentType xContentType
-    ) throws Exception {
+    public BulkProcessor add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultPipeline, MediaType mediaType)
+        throws Exception {
         Tuple<BulkRequest, Long> bulkRequestToExecute = null;
         lock.lock();
         try {
             ensureOpen();
-            bulkRequest.add(data, defaultIndex, null, null, defaultPipeline, null, true, xContentType);
+            bulkRequest.add(data, defaultIndex, null, null, defaultPipeline, null, true, mediaType);
             bulkRequestToExecute = newBulkRequestIfNeeded();
         } finally {
             lock.unlock();
@@ -543,6 +544,11 @@ public void flush() {
         }
     }
 
+    /**
+     * Flush for bulk processor
+     *
+     * @opensearch.internal
+     */
     class Flush implements Runnable {
         @Override
         public void run() {
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkRequest.java b/server/src/main/java/org/opensearch/action/bulk/BulkRequest.java
index e3bf5bced5072..65043da6c2684 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkRequest.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkRequest.java
@@ -45,13 +45,13 @@
 import org.opensearch.action.support.replication.ReplicationRequest;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 
 import java.io.IOException;
@@ -70,6 +70,8 @@
  *
  * Note that we only support refresh on the bulk request not per item.
  * @see org.opensearch.client.Client#bulk(BulkRequest)
+ *
+ * @opensearch.internal
  */
 public class BulkRequest extends ActionRequest implements CompositeIndicesRequest, WriteRequest<BulkRequest>, Accountable {
 
@@ -234,30 +236,30 @@ public long estimatedSizeInBytes() {
     /**
      * Adds a framed data in binary format
      */
-    public BulkRequest add(byte[] data, int from, int length, XContentType xContentType) throws IOException {
-        return add(data, from, length, null, xContentType);
+    public BulkRequest add(byte[] data, int from, int length, MediaType mediaType) throws IOException {
+        return add(data, from, length, null, mediaType);
     }
 
     /**
      * Adds a framed data in binary format
      */
-    public BulkRequest add(byte[] data, int from, int length, @Nullable String defaultIndex, XContentType xContentType) throws IOException {
-        return add(new BytesArray(data, from, length), defaultIndex, xContentType);
+    public BulkRequest add(byte[] data, int from, int length, @Nullable String defaultIndex, MediaType mediaType) throws IOException {
+        return add(new BytesArray(data, from, length), defaultIndex, mediaType);
     }
 
     /**
      * Adds a framed data in binary format
      */
-    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, XContentType xContentType) throws IOException {
-        return add(data, defaultIndex, null, null, null, null, true, xContentType);
+    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, MediaType mediaType) throws IOException {
+        return add(data, defaultIndex, null, null, null, null, true, mediaType);
     }
 
     /**
      * Adds a framed data in binary format
      */
-    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, boolean allowExplicitIndex, XContentType xContentType)
+    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, boolean allowExplicitIndex, MediaType mediaType)
         throws IOException {
-        return add(data, defaultIndex, null, null, null, null, allowExplicitIndex, xContentType);
+        return add(data, defaultIndex, null, null, null, null, allowExplicitIndex, mediaType);
     }
 
     public BulkRequest add(
@@ -267,9 +269,9 @@ public BulkRequest add(
         @Nullable FetchSourceContext defaultFetchSourceContext,
         @Nullable String defaultPipeline,
         boolean allowExplicitIndex,
-        XContentType xContentType
+        MediaType mediaType
     ) throws IOException {
-        return add(data, defaultIndex, defaultRouting, defaultFetchSourceContext, defaultPipeline, null, allowExplicitIndex, xContentType);
+        return add(data, defaultIndex, defaultRouting, defaultFetchSourceContext, defaultPipeline, null, allowExplicitIndex, mediaType);
     }
 
     public BulkRequest add(
@@ -280,12 +282,12 @@ public BulkRequest add(
         @Nullable String defaultPipeline,
         @Nullable Boolean defaultRequireAlias,
         boolean allowExplicitIndex,
-        XContentType xContentType
+        MediaType mediaType
     ) throws IOException {
         String routing = valueOrDefault(defaultRouting, globalRouting);
         String pipeline = valueOrDefault(defaultPipeline, globalPipeline);
         Boolean requireAlias = valueOrDefault(defaultRequireAlias, globalRequireAlias);
-        new BulkRequestParser(true).parse(
+        new BulkRequestParser().parse(
             data,
             defaultIndex,
             routing,
@@ -293,8 +295,8 @@ public BulkRequest add(
             pipeline,
             requireAlias,
             allowExplicitIndex,
-            xContentType,
-            (indexRequest, type) -> internalAdd(indexRequest),
+            mediaType,
+            this::internalAdd,
             this::internalAdd,
             this::add
         );
@@ -461,7 +463,7 @@ private void applyGlobalMandatoryParameters(DocWriteRequest<?> request) {
     }
 
     private static String valueOrDefault(String value, String globalDefault) {
-        if (Strings.isNullOrEmpty(value) && !Strings.isNullOrEmpty(globalDefault)) {
+        if (Strings.isNullOrEmpty(value) && Strings.isNullOrEmpty(globalDefault) == false) {
             return globalDefault;
         }
         return value;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkRequestBuilder.java b/server/src/main/java/org/opensearch/action/bulk/BulkRequestBuilder.java
index c58877e48a7eb..08eee82a53cf9 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkRequestBuilder.java
@@ -46,10 +46,13 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaType;
 
 /**
  * A bulk request holds an ordered {@link IndexRequest}s and {@link DeleteRequest}s and allows to executes
  * it in a single batch.
+ *
+ * @opensearch.internal
  */
 public class BulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkResponse> implements WriteRequestBuilder<BulkRequestBuilder> {
 
@@ -122,9 +125,8 @@ public BulkRequestBuilder add(byte[] data, int from, int length, XContentType xC
     /**
      * Adds a framed data in binary format
      */
-    public BulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, XContentType xContentType)
-        throws Exception {
-        request.add(data, from, length, defaultIndex, xContentType);
+    public BulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, MediaType mediaType) throws Exception {
+        request.add(data, from, length, defaultIndex, mediaType);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkRequestHandler.java b/server/src/main/java/org/opensearch/action/bulk/BulkRequestHandler.java
index 5b4ec5cf8679a..ff40a12cb9087 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkRequestHandler.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkRequestHandler.java
@@ -34,7 +34,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.Scheduler;
 
 import java.util.concurrent.CountDownLatch;
@@ -44,6 +44,8 @@
 
 /**
  * Implements the low-level details of bulk request handling
+ *
+ * @opensearch.internal
  */
 public final class BulkRequestHandler {
     private final Logger logger;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkRequestParser.java b/server/src/main/java/org/opensearch/action/bulk/BulkRequestParser.java
index 042e104f70c7f..3fadfe5f2cd6a 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkRequestParser.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkRequestParser.java
@@ -37,15 +37,17 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -53,7 +55,7 @@
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.function.BiConsumer;
+import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -61,11 +63,12 @@
 
 /**
  * Helper to parse bulk requests. This should be considered an internal class.
+ *
+ * @opensearch.internal
  */
 public final class BulkRequestParser {
 
     private static final ParseField INDEX = new ParseField("_index");
-    private static final ParseField TYPE = new ParseField("_type");
     private static final ParseField ID = new ParseField("_id");
     private static final ParseField ROUTING = new ParseField("routing");
     private static final ParseField OP_TYPE = new ParseField("op_type");
@@ -78,16 +81,7 @@ public final class BulkRequestParser {
     private static final ParseField IF_PRIMARY_TERM = new ParseField("if_primary_term");
     private static final ParseField REQUIRE_ALIAS = new ParseField(DocWriteRequest.REQUIRE_ALIAS);
 
-    // TODO: Remove this parameter once the BulkMonitoring endpoint has been removed
-    private final boolean errorOnType;
-
-    /**
-     * Create a new parser.
-     * @param errorOnType whether to allow _type information in the index line; used by BulkMonitoring
-     */
-    public BulkRequestParser(boolean errorOnType) {
-        this.errorOnType = errorOnType;
-    }
+    private static final Set<String> VALID_ACTIONS = Set.of("create", "delete", "index", "update");
 
     private static int findNextMarker(byte marker, int from, BytesReference data) {
         final int res = data.indexOf(marker, from);
@@ -109,10 +103,10 @@ private static BytesReference sliceTrimmingCarriageReturn(
         BytesReference bytesReference,
         int from,
         int nextMarker,
-        XContentType xContentType
+        MediaType mediaType
     ) {
         final int length;
-        if (XContentType.JSON == xContentType && bytesReference.get(nextMarker - 1) == (byte) '\r') {
+        if (MediaTypeRegistry.JSON == mediaType && bytesReference.get(nextMarker - 1) == (byte) '\r') {
             length = nextMarker - from - 1;
         } else {
             length = nextMarker - from;
@@ -133,12 +127,12 @@ public void parse(
         @Nullable String defaultPipeline,
         @Nullable Boolean defaultRequireAlias,
         boolean allowExplicitIndex,
-        XContentType xContentType,
-        BiConsumer<IndexRequest, String> indexRequestConsumer,
+        MediaType mediaType,
+        Consumer<IndexRequest> indexRequestConsumer,
         Consumer<UpdateRequest> updateRequestConsumer,
         Consumer<DeleteRequest> deleteRequestConsumer
     ) throws IOException {
-        XContent xContent = xContentType.xContent();
+        XContent xContent = mediaType.xContent();
         int line = 0;
         int from = 0;
         byte marker = xContent.streamSeparator();
@@ -188,9 +182,17 @@ public void parse(
                     );
                 }
                 String action = parser.currentName();
+                if (action == null || VALID_ACTIONS.contains(action) == false) {
+                    throw new IllegalArgumentException(
+                        "Malformed action/metadata line ["
+                            + line
+                            + "], expected one of [create, delete, index, update] but found ["
+                            + action
+                            + "]"
+                    );
+                }
 
                 String index = defaultIndex;
-                String type = null;
                 String id = null;
                 String routing = defaultRouting;
                 FetchSourceContext fetchSourceContext = defaultFetchSourceContext;
@@ -203,7 +205,7 @@ public void parse(
                 String pipeline = defaultPipeline;
                 boolean requireAlias = defaultRequireAlias != null && defaultRequireAlias;
 
-                // at this stage, next token can either be END_OBJECT (and use default index and type, with auto generated id)
+                // at this stage, next token can either be END_OBJECT (and use default index with auto generated id)
                 // or START_OBJECT which will have another set of parameters
                 token = parser.nextToken();
 
@@ -218,13 +220,6 @@ public void parse(
                                     throw new IllegalArgumentException("explicit index in bulk is not allowed");
                                 }
                                 index = stringDeduplicator.computeIfAbsent(parser.text(), Function.identity());
-                            } else if (TYPE.match(currentFieldName, parser.getDeprecationHandler())) {
-                                if (errorOnType) {
-                                    throw new IllegalArgumentException(
-                                        "Action/metadata line [" + line + "] contains an unknown parameter [" + currentFieldName + "]"
-                                    );
-                                }
-                                type = stringDeduplicator.computeIfAbsent(parser.text(), Function.identity());
                             } else if (ID.match(currentFieldName, parser.getDeprecationHandler())) {
                                 id = parser.text();
                             } else if (ROUTING.match(currentFieldName, parser.getDeprecationHandler())) {
@@ -319,9 +314,8 @@ public void parse(
                                     .setPipeline(pipeline)
                                     .setIfSeqNo(ifSeqNo)
                                     .setIfPrimaryTerm(ifPrimaryTerm)
-                                    .source(sliceTrimmingCarriageReturn(data, from, nextMarker, xContentType), xContentType)
-                                    .setRequireAlias(requireAlias),
-                                type
+                                    .source(sliceTrimmingCarriageReturn(data, from, nextMarker, mediaType), mediaType)
+                                    .setRequireAlias(requireAlias)
                             );
                         } else {
                             indexRequestConsumer.accept(
@@ -333,9 +327,8 @@ public void parse(
                                     .setPipeline(pipeline)
                                     .setIfSeqNo(ifSeqNo)
                                     .setIfPrimaryTerm(ifPrimaryTerm)
-                                    .source(sliceTrimmingCarriageReturn(data, from, nextMarker, xContentType), xContentType)
-                                    .setRequireAlias(requireAlias),
-                                type
+                                    .source(sliceTrimmingCarriageReturn(data, from, nextMarker, mediaType), mediaType)
+                                    .setRequireAlias(requireAlias)
                             );
                         }
                     } else if ("create".equals(action)) {
@@ -348,9 +341,8 @@ public void parse(
                                 .setPipeline(pipeline)
                                 .setIfSeqNo(ifSeqNo)
                                 .setIfPrimaryTerm(ifPrimaryTerm)
-                                .source(sliceTrimmingCarriageReturn(data, from, nextMarker, xContentType), xContentType)
-                                .setRequireAlias(requireAlias),
-                            type
+                                .source(sliceTrimmingCarriageReturn(data, from, nextMarker, mediaType), mediaType)
+                                .setRequireAlias(requireAlias)
                         );
                     } else if ("update".equals(action)) {
                         if (version != Versions.MATCH_ANY || versionType != VersionType.INTERNAL) {
@@ -368,7 +360,7 @@ public void parse(
                             .routing(routing);
                         try (
                             XContentParser sliceParser = createParser(
-                                sliceTrimmingCarriageReturn(data, from, nextMarker, xContentType),
+                                sliceTrimmingCarriageReturn(data, from, nextMarker, mediaType),
                                 xContent
                             )
                         ) {
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkResponse.java b/server/src/main/java/org/opensearch/action/bulk/BulkResponse.java
index 751ad567c8639..42d6a9f7f31b7 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkResponse.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkResponse.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,14 +47,16 @@
 import java.util.Iterator;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.throwUnknownField;
-import static org.opensearch.common.xcontent.XContentParserUtils.throwUnknownToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.throwUnknownField;
+import static org.opensearch.core.xcontent.XContentParserUtils.throwUnknownToken;
 
 /**
  * A response of a bulk execution. Holding a response for each item responding (in order) of the
  * bulk requests. Each item holds the index/type/id is operated on, and if it failed or not (with the
  * failure message).
+ *
+ * @opensearch.internal
  */
 public class BulkResponse extends ActionResponse implements Iterable<BulkItemResponse>, StatusToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkShardRequest.java b/server/src/main/java/org/opensearch/action/bulk/BulkShardRequest.java
index b082395263875..0441fde4fe20c 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkShardRequest.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkShardRequest.java
@@ -38,15 +38,20 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
 import org.opensearch.action.support.replication.ReplicationRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.stream.Stream;
 
+/**
+ * A bulk shard request targeting a specific shard ID
+ *
+ * @opensearch.internal
+ */
 public class BulkShardRequest extends ReplicatedWriteRequest<BulkShardRequest> implements Accountable {
 
     public static final Version COMPACT_SHARD_ID_VERSION = LegacyESVersion.V_7_9_0;
diff --git a/server/src/main/java/org/opensearch/action/bulk/BulkShardResponse.java b/server/src/main/java/org/opensearch/action/bulk/BulkShardResponse.java
index 18d954a4feb23..d8414a57fcafd 100644
--- a/server/src/main/java/org/opensearch/action/bulk/BulkShardResponse.java
+++ b/server/src/main/java/org/opensearch/action/bulk/BulkShardResponse.java
@@ -37,12 +37,17 @@
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.support.WriteResponse;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Transport response for a bulk shard request
+ *
+ * @opensearch.internal
+ */
 public class BulkShardResponse extends ReplicationResponse implements WriteResponse {
 
     private static final Version COMPACT_SHARD_ID_VERSION = LegacyESVersion.V_7_9_0;
diff --git a/server/src/main/java/org/opensearch/action/bulk/MappingUpdatePerformer.java b/server/src/main/java/org/opensearch/action/bulk/MappingUpdatePerformer.java
index c0eb29e4c112f..c0b6d7049a0e9 100644
--- a/server/src/main/java/org/opensearch/action/bulk/MappingUpdatePerformer.java
+++ b/server/src/main/java/org/opensearch/action/bulk/MappingUpdatePerformer.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.Mapping;
-import org.opensearch.index.shard.ShardId;
 
+/**
+ * Updates the mappings on the cluster manager
+ *
+ * @opensearch.internal
+ */
 public interface MappingUpdatePerformer {
 
     /**
-     * Update the mappings on the master.
+     * Update the mappings on the cluster-manager.
      */
     void updateMappings(Mapping update, ShardId shardId, ActionListener<Void> listener);
 
diff --git a/server/src/main/java/org/opensearch/action/bulk/Retry.java b/server/src/main/java/org/opensearch/action/bulk/Retry.java
index bb1197699d894..338355e214eb8 100644
--- a/server/src/main/java/org/opensearch/action/bulk/Retry.java
+++ b/server/src/main/java/org/opensearch/action/bulk/Retry.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.action.bulk;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.action.ActionListener;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteTransportException;
@@ -49,6 +49,8 @@
 
 /**
  * Encapsulates synchronous and asynchronous retry logic.
+ *
+ * @opensearch.internal
  */
 public class Retry {
     private final BackoffPolicy backoffPolicy;
@@ -92,6 +94,11 @@ public PlainActionFuture<BulkResponse> withBackoff(
         return future;
     }
 
+    /**
+     * Retry handler
+     *
+     * @opensearch.internal
+     */
     static class RetryHandler implements ActionListener<BulkResponse> {
         private static final RestStatus RETRY_STATUS = RestStatus.TOO_MANY_REQUESTS;
         private static final Logger logger = LogManager.getLogger(RetryHandler.class);
diff --git a/server/src/main/java/org/opensearch/action/bulk/TransportBulkAction.java b/server/src/main/java/org/opensearch/action/bulk/TransportBulkAction.java
index 560fd1d8a45b3..387aff7194813 100644
--- a/server/src/main/java/org/opensearch/action/bulk/TransportBulkAction.java
+++ b/server/src/main/java/org/opensearch/action/bulk/TransportBulkAction.java
@@ -35,13 +35,11 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.SparseFixedBitSet;
-import org.opensearch.Assertions;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.ExceptionsHelper;
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
@@ -73,13 +71,17 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.Index;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.IndexingStats.Stats.DocStatusStats;
 import org.opensearch.indices.IndexClosedException;
+import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.node.NodeClosedException;
@@ -112,6 +114,8 @@
 /**
  * Groups bulk request items by shard, optionally creating non-existent indices and
  * delegates to {@link TransportShardBulkAction} for shard-level bulk execution
+ *
+ * @opensearch.internal
  */
 public class TransportBulkAction extends HandledTransportAction<BulkRequest, BulkResponse> {
 
@@ -128,6 +132,7 @@ public class TransportBulkAction extends HandledTransportAction<BulkRequest, Bul
     private final IndexNameExpressionResolver indexNameExpressionResolver;
     private static final String DROPPED_ITEM_WITH_AUTO_GENERATED_ID = "auto-generated";
     private final IndexingPressureService indexingPressureService;
+    private final IndicesService indicesService;
     private final SystemIndices systemIndices;
 
     @Inject
@@ -142,6 +147,7 @@ public TransportBulkAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         AutoCreateIndex autoCreateIndex,
         IndexingPressureService indexingPressureService,
+        IndicesService indicesService,
         SystemIndices systemIndices
     ) {
         this(
@@ -155,6 +161,7 @@ public TransportBulkAction(
             indexNameExpressionResolver,
             autoCreateIndex,
             indexingPressureService,
+            indicesService,
             systemIndices,
             System::nanoTime
         );
@@ -171,6 +178,7 @@ public TransportBulkAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         AutoCreateIndex autoCreateIndex,
         IndexingPressureService indexingPressureService,
+        IndicesService indicesService,
         SystemIndices systemIndices,
         LongSupplier relativeTimeProvider
     ) {
@@ -186,6 +194,7 @@ public TransportBulkAction(
         this.client = client;
         this.indexNameExpressionResolver = indexNameExpressionResolver;
         this.indexingPressureService = indexingPressureService;
+        this.indicesService = indicesService;
         this.systemIndices = systemIndices;
         clusterService.addStateApplier(this.ingestForwarder);
     }
@@ -452,7 +461,7 @@ void createIndex(String index, TimeValue timeout, Version minNodeVersion, Action
         CreateIndexRequest createIndexRequest = new CreateIndexRequest();
         createIndexRequest.index(index);
         createIndexRequest.cause("auto(bulk api)");
-        createIndexRequest.masterNodeTimeout(timeout);
+        createIndexRequest.clusterManagerNodeTimeout(timeout);
         if (minNodeVersion.onOrAfter(LegacyESVersion.V_7_8_0)) {
             client.execute(AutoCreateAction.INSTANCE, createIndexRequest, listener);
         } else {
@@ -481,7 +490,9 @@ private long buildTookInMillis(long startTimeNanos) {
     /**
      * retries on retryable cluster blocks, resolves item requests,
      * constructs shard bulk requests and delegates execution to shard bulk action
-     * */
+     *
+     * @opensearch.internal
+     */
     private final class BulkOperation extends ActionRunnable<BulkResponse> {
         private final Task task;
         private BulkRequest bulkRequest; // set to null once all requests are sent out
@@ -596,14 +607,25 @@ protected void doRun() {
             }
 
             if (requestsByShard.isEmpty()) {
-                listener.onResponse(
-                    new BulkResponse(responses.toArray(new BulkItemResponse[responses.length()]), buildTookInMillis(startTimeNanos))
-                );
+                BulkItemResponse[] response = responses.toArray(new BulkItemResponse[responses.length()]);
+                long tookMillis = buildTookInMillis(startTimeNanos);
+
+                DocStatusStats stats = new DocStatusStats();
+                for (BulkItemResponse itemResponse : response) {
+                    if (itemResponse != null) {
+                        stats.inc(itemResponse.status());
+                    }
+                }
+
+                indicesService.addDocStatusStats(stats);
+                listener.onResponse(new BulkResponse(response, tookMillis));
                 return;
             }
 
             final AtomicInteger counter = new AtomicInteger(requestsByShard.size());
+            final DocStatusStats docStatusStats = new DocStatusStats();
             String nodeId = clusterService.localNode().getId();
+
             for (Map.Entry<ShardId, List<BulkItemRequest>> entry : requestsByShard.entrySet()) {
                 final ShardId shardId = entry.getKey();
                 final List<BulkItemRequest> requests = entry.getValue();
@@ -633,8 +655,11 @@ public void onResponse(BulkShardResponse bulkShardResponse) {
                             if (bulkItemResponse.getResponse() != null) {
                                 bulkItemResponse.getResponse().setShardInfo(bulkShardResponse.getShardInfo());
                             }
+
+                            docStatusStats.inc(bulkItemResponse.status());
                             responses.set(bulkItemResponse.getItemId(), bulkItemResponse);
                         }
+
                         if (counter.decrementAndGet() == 0) {
                             finishHim();
                         }
@@ -645,22 +670,24 @@ public void onFailure(Exception e) {
                         // create failures for all relevant requests
                         for (BulkItemRequest request : requests) {
                             final String indexName = concreteIndices.getConcreteIndex(request.index()).getName();
-                            DocWriteRequest<?> docWriteRequest = request.request();
-                            responses.set(
+                            final DocWriteRequest<?> docWriteRequest = request.request();
+                            final BulkItemResponse bulkItemResponse = new BulkItemResponse(
                                 request.id(),
-                                new BulkItemResponse(
-                                    request.id(),
-                                    docWriteRequest.opType(),
-                                    new BulkItemResponse.Failure(indexName, docWriteRequest.id(), e)
-                                )
+                                docWriteRequest.opType(),
+                                new BulkItemResponse.Failure(indexName, docWriteRequest.id(), e)
                             );
+
+                            docStatusStats.inc(bulkItemResponse.status());
+                            responses.set(request.id(), bulkItemResponse);
                         }
+
                         if (counter.decrementAndGet() == 0) {
                             finishHim();
                         }
                     }
 
                     private void finishHim() {
+                        indicesService.addDocStatusStats(docStatusStats);
                         listener.onResponse(
                             new BulkResponse(responses.toArray(new BulkItemResponse[responses.length()]), buildTookInMillis(startTimeNanos))
                         );
@@ -767,9 +794,18 @@ void executeBulk(
         final AtomicArray<BulkItemResponse> responses,
         Map<String, IndexNotFoundException> indicesThatCannotBeCreated
     ) {
+        /*
+         * We are not wrapping the listener here to capture the response codes for performance benefits. It will
+         * be saving us an iteration over the responses array
+         */
         new BulkOperation(task, bulkRequest, listener, responses, startTimeNanos, indicesThatCannotBeCreated).run();
     }
 
+    /**
+     * Concrete indices
+     *
+     * @opensearch.internal
+     */
     private static class ConcreteIndices {
         private final ClusterState state;
         private final IndexNameExpressionResolver indexNameExpressionResolver;
@@ -872,6 +908,11 @@ public boolean isForceExecution() {
         );
     }
 
+    /**
+     * A modifier for a bulk request
+     *
+     * @opensearch.internal
+     */
     static final class BulkRequestModifier implements Iterator<DocWriteRequest<?>> {
 
         final BulkRequest bulkRequest;
diff --git a/server/src/main/java/org/opensearch/action/bulk/TransportShardBulkAction.java b/server/src/main/java/org/opensearch/action/bulk/TransportShardBulkAction.java
index cc9f20b7aa256..fddda0ef1f9a7 100644
--- a/server/src/main/java/org/opensearch/action/bulk/TransportShardBulkAction.java
+++ b/server/src/main/java/org/opensearch/action/bulk/TransportShardBulkAction.java
@@ -37,7 +37,7 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.MessageSupplier;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
@@ -46,55 +46,80 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.ChannelActionListener;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.action.support.replication.ReplicationOperation;
+import org.opensearch.action.support.replication.ReplicationTask;
 import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.action.support.replication.TransportWriteAction;
 import org.opensearch.action.update.UpdateHelper;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.action.update.UpdateResponse;
+import org.opensearch.client.transport.NoNodeAvailableException;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.action.index.MappingUpdatedAction;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.AllocationId;
+import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.index.IndexingPressureService;
+import org.opensearch.index.SegmentReplicationPressureService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.MapperException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.SourceToParse;
+import org.opensearch.index.remote.RemoteStorePressureService;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.node.NodeClosedException;
+import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
+import org.opensearch.transport.TransportChannel;
+import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.Executor;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.LongSupplier;
 
-/** Performs shard-level bulk (index, delete or update) operations */
+/**
+ * Performs shard-level bulk (index, delete or update) operations
+ *
+ * @opensearch.internal
+ */
 public class TransportShardBulkAction extends TransportWriteAction<BulkShardRequest, BulkShardRequest, BulkShardResponse> {
 
     public static final String ACTION_NAME = BulkAction.NAME + "[s]";
@@ -110,6 +135,17 @@ public class TransportShardBulkAction extends TransportWriteAction<BulkShardRequ
 
     private final UpdateHelper updateHelper;
     private final MappingUpdatedAction mappingUpdatedAction;
+    private final SegmentReplicationPressureService segmentReplicationPressureService;
+    private final RemoteStorePressureService remoteStorePressureService;
+
+    /**
+     * This action is used for performing primary term validation. With remote translog enabled, the translogs would
+     * be durably persisted in remote store. Without remote translog, current transport replication calls does primary
+     * term validation as well as logically replicate the data. With remote translog, the primary would make calls to
+     * replicas to perform primary term validation. This make sures an isolated primary fails to ack after primary
+     * term validation in presence of a new primary.
+     */
+    private final String transportPrimaryTermValidationAction;
 
     @Inject
     public TransportShardBulkAction(
@@ -123,6 +159,8 @@ public TransportShardBulkAction(
         UpdateHelper updateHelper,
         ActionFilters actionFilters,
         IndexingPressureService indexingPressureService,
+        SegmentReplicationPressureService segmentReplicationPressureService,
+        RemoteStorePressureService remoteStorePressureService,
         SystemIndices systemIndices
     ) {
         super(
@@ -143,6 +181,214 @@ public TransportShardBulkAction(
         );
         this.updateHelper = updateHelper;
         this.mappingUpdatedAction = mappingUpdatedAction;
+        this.segmentReplicationPressureService = segmentReplicationPressureService;
+        this.remoteStorePressureService = remoteStorePressureService;
+
+        this.transportPrimaryTermValidationAction = ACTION_NAME + "[validate_primary_term]";
+
+        transportService.registerRequestHandler(
+            transportPrimaryTermValidationAction,
+            executor,
+            true,
+            true,
+            PrimaryTermValidationRequest::new,
+            this::handlePrimaryTermValidationRequest
+        );
+    }
+
+    protected void handlePrimaryTermValidationRequest(
+        final PrimaryTermValidationRequest request,
+        final TransportChannel channel,
+        final Task task
+    ) {
+        ActionListener<ReplicaResponse> listener = new ChannelActionListener<>(channel, transportPrimaryTermValidationAction, request);
+        final ShardId shardId = request.getShardId();
+        assert shardId != null : "request shardId must be set";
+        IndexShard replica = getIndexShard(shardId);
+        try {
+            new PrimaryTermValidationReplicaAction(listener, replica, (ReplicationTask) task, request).run();
+        } catch (RuntimeException e) {
+            listener.onFailure(e);
+        }
+    }
+
+    /**
+     * This action is the primary term validation action which is used for doing primary term validation with replicas.
+     * This is only applicable for TransportShardBulkAction because all writes (delete/update/single write/bulk)
+     * ultimately boils down to TransportShardBulkAction and isolated primary could continue to acknowledge if it is not
+     * aware that the primary has changed. This helps achieve the same. More details in java doc of
+     * {@link TransportShardBulkAction#transportPrimaryTermValidationAction}.
+     *
+     * @opensearch.internal
+     */
+    private static final class PrimaryTermValidationReplicaAction extends AbstractRunnable implements ActionListener<Releasable> {
+
+        private final ActionListener<ReplicaResponse> onCompletionListener;
+        private final IndexShard replica;
+        private final ReplicationTask task;
+        private final PrimaryTermValidationRequest request;
+
+        public PrimaryTermValidationReplicaAction(
+            ActionListener<ReplicaResponse> onCompletionListener,
+            IndexShard replica,
+            ReplicationTask task,
+            PrimaryTermValidationRequest request
+        ) {
+            this.onCompletionListener = onCompletionListener;
+            this.replica = replica;
+            this.task = task;
+            this.request = request;
+        }
+
+        @Override
+        public void onResponse(Releasable releasable) {
+            setPhase(task, "finished");
+            onCompletionListener.onResponse(new ReplicaResponse(SequenceNumbers.NO_OPS_PERFORMED, SequenceNumbers.NO_OPS_PERFORMED));
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            setPhase(task, "failed");
+            onCompletionListener.onFailure(e);
+        }
+
+        @Override
+        protected void doRun() throws Exception {
+            setPhase(task, "primary-term-validation");
+            final String actualAllocationId = this.replica.routingEntry().allocationId().getId();
+            if (actualAllocationId.equals(request.getTargetAllocationID()) == false) {
+                throw new ShardNotFoundException(
+                    this.replica.shardId(),
+                    "expected allocation id [{}] but found [{}]",
+                    request.getTargetAllocationID(),
+                    actualAllocationId
+                );
+            }
+            // Check operation primary term against the incoming primary term
+            // If the request primary term is low, then trigger lister failure
+            if (request.getPrimaryTerm() < replica.getOperationPrimaryTerm()) {
+                final String message = String.format(
+                    Locale.ROOT,
+                    "%s operation primary term [%d] is too old (current [%d])",
+                    request.getShardId(),
+                    request.getPrimaryTerm(),
+                    replica.getOperationPrimaryTerm()
+                );
+                onFailure(new IllegalStateException(message));
+            } else {
+                onResponse(null);
+            }
+        }
+    }
+
+    /**
+     * Primary term validation request sent to a specific allocation id
+     *
+     * @opensearch.internal
+     */
+    protected static final class PrimaryTermValidationRequest extends TransportRequest {
+
+        /**
+         * {@link AllocationId#getId()} of the shard this request is sent to
+         **/
+        private final String targetAllocationID;
+        private final long primaryTerm;
+        private final ShardId shardId;
+
+        public PrimaryTermValidationRequest(String targetAllocationID, long primaryTerm, ShardId shardId) {
+            this.targetAllocationID = Objects.requireNonNull(targetAllocationID);
+            this.primaryTerm = primaryTerm;
+            this.shardId = Objects.requireNonNull(shardId);
+        }
+
+        public PrimaryTermValidationRequest(StreamInput in) throws IOException {
+            super(in);
+            targetAllocationID = in.readString();
+            primaryTerm = in.readVLong();
+            shardId = new ShardId(in);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(targetAllocationID);
+            out.writeVLong(primaryTerm);
+            shardId.writeTo(out);
+        }
+
+        @Override
+        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+            return new ReplicationTask(id, type, action, getDescription(), parentTaskId, headers);
+        }
+
+        public String getTargetAllocationID() {
+            return targetAllocationID;
+        }
+
+        public long getPrimaryTerm() {
+            return primaryTerm;
+        }
+
+        public ShardId getShardId() {
+            return shardId;
+        }
+
+        @Override
+        public String getDescription() {
+            return toString();
+        }
+
+        @Override
+        public String toString() {
+            return "PrimaryTermValidationRequest ["
+                + shardId
+                + "] for targetAllocationID ["
+                + targetAllocationID
+                + "] with primaryTerm ["
+                + primaryTerm
+                + "]";
+        }
+    }
+
+    @Override
+    protected ReplicationOperation.Replicas<BulkShardRequest> primaryTermValidationReplicasProxy() {
+        return new PrimaryTermValidationProxy();
+    }
+
+    /**
+     * This {@link org.opensearch.action.support.replication.TransportReplicationAction.ReplicasProxy} implementation is
+     * used for primary term validation and is only relevant for TransportShardBulkAction replication action.
+     *
+     * @opensearch.internal
+     */
+    private final class PrimaryTermValidationProxy extends WriteActionReplicasProxy {
+
+        @Override
+        public void performOn(
+            ShardRouting replica,
+            BulkShardRequest request,
+            long primaryTerm,
+            long globalCheckpoint,
+            long maxSeqNoOfUpdatesOrDeletes,
+            ActionListener<ReplicationOperation.ReplicaResponse> listener
+        ) {
+            String nodeId = replica.currentNodeId();
+            final DiscoveryNode node = clusterService.state().nodes().get(nodeId);
+            if (node == null) {
+                listener.onFailure(new NoNodeAvailableException("unknown node [" + nodeId + "]"));
+                return;
+            }
+            final PrimaryTermValidationRequest validationRequest = new PrimaryTermValidationRequest(
+                replica.allocationId().getId(),
+                primaryTerm,
+                replica.shardId()
+            );
+            final ActionListenerResponseHandler<ReplicaResponse> handler = new ActionListenerResponseHandler<>(
+                listener,
+                ReplicaResponse::new
+            );
+            transportService.sendRequest(node, transportPrimaryTermValidationAction, validationRequest, transportOptions, handler);
+        }
     }
 
     @Override
@@ -165,7 +411,7 @@ protected void dispatchedShardOperationOnPrimary(
         performOnPrimary(request, primary, updateHelper, threadPool::absoluteTimeInMillis, (update, shardId, mappingListener) -> {
             assert update != null;
             assert shardId != null;
-            mappingUpdatedAction.updateMappingOnMaster(shardId.getIndex(), update, mappingListener);
+            mappingUpdatedAction.updateMappingOnClusterManager(shardId.getIndex(), update, mappingListener);
         }, mappingUpdateListener -> observer.waitForNextChange(new ClusterStateObserver.Listener() {
             @Override
             public void onNewClusterState(ClusterState state) {
@@ -189,6 +435,14 @@ protected long primaryOperationSize(BulkShardRequest request) {
         return request.ramBytesUsed();
     }
 
+    @Override
+    public ReplicationMode getReplicationMode(IndexShard indexShard) {
+        if (indexShard.isRemoteTranslogEnabled()) {
+            return ReplicationMode.PRIMARY_TERM_VALIDATION;
+        }
+        return super.getReplicationMode(indexShard);
+    }
+
     public static void performOnPrimary(
         BulkShardRequest request,
         IndexShard primary,
@@ -276,6 +530,21 @@ private void finishRequest() {
         }.run();
     }
 
+    @Override
+    protected Releasable checkPrimaryLimits(BulkShardRequest request, boolean rerouteWasLocal, boolean localRerouteInitiatedByNodeClient) {
+        if (force(request) == false) {
+            if (segmentReplicationPressureService.isSegmentReplicationBackpressureEnabled()) {
+                segmentReplicationPressureService.isSegrepLimitBreached(request.shardId());
+            }
+            // TODO - While removing remote store flag, this can be encapsulated to single class with common interface for backpressure
+            // service
+            if (remoteStorePressureService.isSegmentsUploadBackpressureEnabled()) {
+                remoteStorePressureService.validateSegmentsUploadLag(request.shardId());
+            }
+        }
+        return super.checkPrimaryLimits(request, rerouteWasLocal, localRerouteInitiatedByNodeClient);
+    }
+
     /**
      * Executes bulk item requests and handles request execution exceptions.
      * @return {@code true} if request completed on this thread and the listener was invoked, {@code false} if the request triggered
@@ -481,7 +750,7 @@ static BulkItemResponse processUpdateResponse(
 
                 if (updateRequest.fetchSource() != null && updateRequest.fetchSource().fetchSource()) {
                     final BytesReference indexSourceAsBytes = updateIndexRequest.source();
-                    final Tuple<XContentType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(
+                    final Tuple<? extends MediaType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(
                         indexSourceAsBytes,
                         true,
                         updateIndexRequest.getContentType()
@@ -599,6 +868,7 @@ private static Engine.Result performOpOnReplica(
                     indexRequest.routing()
                 );
                 result = replica.applyIndexOperationOnReplica(
+                    primaryResponse.getId(),
                     primaryResponse.getSeqNo(),
                     primaryResponse.getPrimaryTerm(),
                     primaryResponse.getVersion(),
@@ -621,8 +891,8 @@ private static Engine.Result performOpOnReplica(
                 throw new IllegalStateException("Unexpected request operation type on replica: " + docWriteRequest.opType().getLowercase());
         }
         if (result.getResultType() == Engine.Result.Type.MAPPING_UPDATE_REQUIRED) {
-            // Even though the primary waits on all nodes to ack the mapping changes to the master
-            // (see MappingUpdatedAction.updateMappingOnMaster) we still need to protect against missing mappings
+            // Even though the primary waits on all nodes to ack the mapping changes to the cluster-manager
+            // (see MappingUpdatedAction.updateMappingOnClusterManager) we still need to protect against missing mappings
             // and wait for them. The reason is concurrent requests. Request r1 which has new field f triggers a
             // mapping update. Assume that that update is first applied on the primary, and only later on the replica
             // (it’s happening concurrently). Request r2, which now arrives on the primary and which also has the new
diff --git a/server/src/main/java/org/opensearch/action/bulk/TransportSingleItemBulkWriteAction.java b/server/src/main/java/org/opensearch/action/bulk/TransportSingleItemBulkWriteAction.java
index a833687d591de..9b901dda24c2b 100644
--- a/server/src/main/java/org/opensearch/action/bulk/TransportSingleItemBulkWriteAction.java
+++ b/server/src/main/java/org/opensearch/action/bulk/TransportSingleItemBulkWriteAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.support.ActionFilters;
@@ -41,11 +40,16 @@
 import org.opensearch.action.support.WriteResponse;
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
-/** use transport bulk action directly */
+/**
+ * use transport bulk action directly
+ *
+ * @opensearch.internal
+ */
 @Deprecated
 public abstract class TransportSingleItemBulkWriteAction<
     Request extends ReplicatedWriteRequest<Request>,
diff --git a/server/src/main/java/org/opensearch/action/bulk/package-info.java b/server/src/main/java/org/opensearch/action/bulk/package-info.java
new file mode 100644
index 0000000000000..45c42c0efa3f2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/bulk/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Bulk API transport handlers. */
+package org.opensearch.action.bulk;
diff --git a/server/src/main/java/org/opensearch/action/delete/DeleteAction.java b/server/src/main/java/org/opensearch/action/delete/DeleteAction.java
index dc58ebee6c356..b93867ca12efe 100644
--- a/server/src/main/java/org/opensearch/action/delete/DeleteAction.java
+++ b/server/src/main/java/org/opensearch/action/delete/DeleteAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to delete a document from an index
+ *
+ * @opensearch.internal
+ */
 public class DeleteAction extends ActionType<DeleteResponse> {
 
     public static final DeleteAction INSTANCE = new DeleteAction();
diff --git a/server/src/main/java/org/opensearch/action/delete/DeleteRequest.java b/server/src/main/java/org/opensearch/action/delete/DeleteRequest.java
index c40933ba9c92e..cb8195b09593f 100644
--- a/server/src/main/java/org/opensearch/action/delete/DeleteRequest.java
+++ b/server/src/main/java/org/opensearch/action/delete/DeleteRequest.java
@@ -40,13 +40,13 @@
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 
@@ -64,6 +64,8 @@
  * @see DeleteResponse
  * @see org.opensearch.client.Client#delete(DeleteRequest)
  * @see org.opensearch.client.Requests#deleteRequest(String)
+ *
+ * @opensearch.internal
  */
 public class DeleteRequest extends ReplicatedWriteRequest<DeleteRequest>
     implements
diff --git a/server/src/main/java/org/opensearch/action/delete/DeleteRequestBuilder.java b/server/src/main/java/org/opensearch/action/delete/DeleteRequestBuilder.java
index f6ee0f4a7b278..0436962ce01d2 100644
--- a/server/src/main/java/org/opensearch/action/delete/DeleteRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/delete/DeleteRequestBuilder.java
@@ -40,6 +40,8 @@
 
 /**
  * A delete document action request builder.
+ *
+ * @opensearch.internal
  */
 public class DeleteRequestBuilder extends ReplicationRequestBuilder<DeleteRequest, DeleteResponse, DeleteRequestBuilder>
     implements
diff --git a/server/src/main/java/org/opensearch/action/delete/DeleteResponse.java b/server/src/main/java/org/opensearch/action/delete/DeleteResponse.java
index 6b000561ad282..e4d44197a8885 100644
--- a/server/src/main/java/org/opensearch/action/delete/DeleteResponse.java
+++ b/server/src/main/java/org/opensearch/action/delete/DeleteResponse.java
@@ -33,20 +33,22 @@
 package org.opensearch.action.delete;
 
 import org.opensearch.action.DocWriteResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * The response of the delete action.
  *
  * @see org.opensearch.action.delete.DeleteRequest
  * @see org.opensearch.client.Client#delete(DeleteRequest)
+ *
+ * @opensearch.internal
  */
 public class DeleteResponse extends DocWriteResponse {
 
@@ -109,6 +111,8 @@ public static void parseXContentFields(XContentParser parser, Builder context) t
      * Builder class for {@link DeleteResponse}. This builder is usually used during xcontent parsing to
      * temporarily store the parsed values, then the {@link DocWriteResponse.Builder#build()} method is called to
      * instantiate the {@link DeleteResponse}.
+     *
+     * @opensearch.internal
      */
     public static class Builder extends DocWriteResponse.Builder {
 
diff --git a/server/src/main/java/org/opensearch/action/delete/TransportDeleteAction.java b/server/src/main/java/org/opensearch/action/delete/TransportDeleteAction.java
index adeebcba28a89..039214459ac21 100644
--- a/server/src/main/java/org/opensearch/action/delete/TransportDeleteAction.java
+++ b/server/src/main/java/org/opensearch/action/delete/TransportDeleteAction.java
@@ -42,6 +42,8 @@
  * Performs the delete operation.
  *
  * Deprecated use TransportBulkAction with a single item instead
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public class TransportDeleteAction extends TransportSingleItemBulkWriteAction<DeleteRequest, DeleteResponse> {
diff --git a/server/src/main/java/org/opensearch/action/explain/ExplainAction.java b/server/src/main/java/org/opensearch/action/explain/ExplainAction.java
index ff534dbf82f6d..e955ecc8a1e45 100644
--- a/server/src/main/java/org/opensearch/action/explain/ExplainAction.java
+++ b/server/src/main/java/org/opensearch/action/explain/ExplainAction.java
@@ -36,6 +36,8 @@
 
 /**
  * Entry point for the explain feature.
+ *
+ * @opensearch.internal
  */
 public class ExplainAction extends ActionType<ExplainResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/explain/ExplainRequest.java b/server/src/main/java/org/opensearch/action/explain/ExplainRequest.java
index 1543c2c95b269..aad5a9853a3c5 100644
--- a/server/src/main/java/org/opensearch/action/explain/ExplainRequest.java
+++ b/server/src/main/java/org/opensearch/action/explain/ExplainRequest.java
@@ -36,12 +36,12 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -53,6 +53,8 @@
 
 /**
  * Explain request encapsulating the explain query and document identifier to get an explanation for.
+ *
+ * @opensearch.internal
  */
 public class ExplainRequest extends SingleShardRequest<ExplainRequest> implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/explain/ExplainRequestBuilder.java b/server/src/main/java/org/opensearch/action/explain/ExplainRequestBuilder.java
index 6839479079845..3031cb6067469 100644
--- a/server/src/main/java/org/opensearch/action/explain/ExplainRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/explain/ExplainRequestBuilder.java
@@ -35,12 +35,14 @@
 import org.opensearch.action.support.single.shard.SingleShardOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 
 /**
  * A builder for {@link ExplainRequest}.
+ *
+ * @opensearch.internal
  */
 public class ExplainRequestBuilder extends SingleShardOperationRequestBuilder<ExplainRequest, ExplainResponse, ExplainRequestBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/action/explain/ExplainResponse.java b/server/src/main/java/org/opensearch/action/explain/ExplainResponse.java
index 6dd1945a38ffc..895f87b83b6ff 100644
--- a/server/src/main/java/org/opensearch/action/explain/ExplainResponse.java
+++ b/server/src/main/java/org/opensearch/action/explain/ExplainResponse.java
@@ -34,17 +34,17 @@
 
 import org.apache.lucene.search.Explanation;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -55,6 +55,8 @@
 
 /**
  * Response containing the score explanation.
+ *
+ * @opensearch.internal
  */
 public class ExplainResponse extends ActionResponse implements StatusToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/explain/TransportExplainAction.java b/server/src/main/java/org/opensearch/action/explain/TransportExplainAction.java
index 9fb16eec7d36b..fb2ccc6ebbf12 100644
--- a/server/src/main/java/org/opensearch/action/explain/TransportExplainAction.java
+++ b/server/src/main/java/org/opensearch/action/explain/TransportExplainAction.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.Explanation;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.single.shard.TransportSingleShardAction;
@@ -44,15 +43,16 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.SearchContext;
@@ -68,6 +68,8 @@
 
 /**
  * Explain transport action. Computes the explain on the targeted shard.
+ *
+ * @opensearch.internal
  */
 // TODO: AggregatedDfs. Currently the idf can be different then when executing a normal search with explain.
 public class TransportExplainAction extends TransportSingleShardAction<ExplainRequest, ExplainResponse> {
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilities.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilities.java
index ffc059f08c70f..260d3d8c4e33f 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilities.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilities.java
@@ -33,15 +33,16 @@
 package org.opensearch.action.fieldcaps;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -59,6 +60,8 @@
 
 /**
  * Describes the capabilities of a field optionally merged across multiple indices.
+ *
+ * @opensearch.internal
  */
 public class FieldCapabilities implements Writeable, ToXContentObject {
 
@@ -293,9 +296,14 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * Builder for field capabilities
+     *
+     * @opensearch.internal
+     */
     static class Builder {
         private String name;
         private String type;
@@ -385,6 +393,11 @@ FieldCapabilities build(boolean withIndices) {
         }
     }
 
+    /**
+     * Inner index capabilities
+     *
+     * @opensearch.internal
+     */
     private static class IndexCaps {
         final String name;
         final boolean isSearchable;
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesAction.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesAction.java
index d10fa5ee69811..e8585e60c8ffd 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesAction.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for a field capabilities request
+ *
+ * @opensearch.internal
+ */
 public class FieldCapabilitiesAction extends ActionType<FieldCapabilitiesResponse> {
 
     public static final FieldCapabilitiesAction INSTANCE = new FieldCapabilitiesAction();
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexRequest.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexRequest.java
index b349d8e2ca26f..09532e58e112f 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexRequest.java
@@ -38,14 +38,19 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.QueryBuilder;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport Request for Retrieving Field Capabilities for an Index
+ *
+ * @opensearch.internal
+ */
 public class FieldCapabilitiesIndexRequest extends ActionRequest implements IndicesRequest {
 
     public static final IndicesOptions INDICES_OPTIONS = IndicesOptions.strictSingleIndexNoExpandForbidClosed();
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java
index 0d7fd91a6bfd8..8baaa3e410a86 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.fieldcaps;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Map;
@@ -44,6 +44,8 @@
 
 /**
  * Response for {@link TransportFieldCapabilitiesIndexAction}.
+ *
+ * @opensearch.internal
  */
 public class FieldCapabilitiesIndexResponse extends ActionResponse implements Writeable {
     private final String indexName;
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequest.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequest.java
index c8391fddf564d..c9bf962238ad8 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequest.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequest.java
@@ -38,11 +38,11 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 
 import java.io.IOException;
@@ -51,6 +51,9 @@
 import java.util.Objects;
 import java.util.Set;
 
+/**
+ * Transport request for retrieving field capabilities for an explicit list of fields
+ */
 public final class FieldCapabilitiesRequest extends ActionRequest implements IndicesRequest.Replaceable, ToXContentObject {
     public static final String NAME = "field_caps_request";
 
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestBuilder.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestBuilder.java
index 3c1f11c047ef4..70a90b98bdf25 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.index.query.QueryBuilder;
 
+/**
+ * Transport request builder for retrieving field capabilities
+ *
+ * @opensearch.internal
+ */
 public class FieldCapabilitiesRequestBuilder extends ActionRequestBuilder<FieldCapabilitiesRequest, FieldCapabilitiesResponse> {
     public FieldCapabilitiesRequestBuilder(OpenSearchClient client, FieldCapabilitiesAction action, String... indices) {
         super(client, action, new FieldCapabilitiesRequest().indices(indices));
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponse.java b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponse.java
index 90b35d6e14e4e..d919b96f5815e 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponse.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponse.java
@@ -33,17 +33,18 @@
 package org.opensearch.action.fieldcaps;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -56,6 +57,8 @@
 
 /**
  * Response for {@link FieldCapabilitiesRequest} requests.
+ *
+ * @opensearch.internal
  */
 public class FieldCapabilitiesResponse extends ActionResponse implements ToXContentObject {
     private static final ParseField INDICES_FIELD = new ParseField("indices");
@@ -217,6 +220,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/IndexFieldCapabilities.java b/server/src/main/java/org/opensearch/action/fieldcaps/IndexFieldCapabilities.java
index d0629a46c9d4a..60c7c85cae55d 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/IndexFieldCapabilities.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/IndexFieldCapabilities.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.fieldcaps;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -46,6 +46,8 @@
 
 /**
  * Describes the capabilities of a field in a single index.
+ *
+ * @opensearch.internal
  */
 public class IndexFieldCapabilities implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesAction.java b/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesAction.java
index 07254db46d567..4c9e10cba52e7 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesAction.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.fieldcaps;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
@@ -40,9 +39,10 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterAware;
@@ -58,6 +58,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Transport action for field capabilities requests
+ *
+ * @opensearch.internal
+ */
 public class TransportFieldCapabilitiesAction extends HandledTransportAction<FieldCapabilitiesRequest, FieldCapabilitiesResponse> {
     private final ThreadPool threadPool;
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java b/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java
index a4807eff1acb4..b303dfea05c0a 100644
--- a/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.NoShardAvailableActionException;
@@ -48,19 +47,21 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.FailAwareWeightedRouting;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.logging.LoggerMessageFormat;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.logging.LoggerMessageFormat;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.query.MatchAllQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.builder.SearchSourceBuilder;
@@ -85,6 +86,11 @@
 
 import static org.opensearch.action.support.TransportActions.isShardNotAvailableException;
 
+/**
+ * Transport action for field capabilities request in an index
+ *
+ * @opensearch.internal
+ */
 public class TransportFieldCapabilitiesIndexAction extends HandledTransportAction<
     FieldCapabilitiesIndexRequest,
     FieldCapabilitiesIndexResponse> {
@@ -212,6 +218,8 @@ private ClusterBlockException checkRequestBlock(ClusterState state, String concr
      * An action that executes on each shard sequentially until it finds one that can match the provided
      * {@link FieldCapabilitiesIndexRequest#indexFilter()}. In which case the shard is used
      * to create the final {@link FieldCapabilitiesIndexResponse}.
+     *
+     * @opensearch.internal
      */
     class AsyncShardsAction {
         private final FieldCapabilitiesIndexRequest request;
@@ -255,16 +263,18 @@ private void onFailure(ShardRouting shardRouting, Exception e) {
             tryNext(e, false);
         }
 
-        private ShardRouting nextRoutingOrNull() {
+        private ShardRouting nextRoutingOrNull(Exception failure) {
             if (shardsIt.size() == 0 || shardIndex >= shardsIt.size()) {
                 return null;
             }
-            ShardRouting next = shardsIt.get(shardIndex).nextOrNull();
+            ShardRouting next = FailAwareWeightedRouting.getInstance()
+                .findNext(shardsIt.get(shardIndex), clusterService.state(), failure, this::moveToNextShard);
+
             if (next != null) {
                 return next;
             }
             moveToNextShard();
-            return nextRoutingOrNull();
+            return nextRoutingOrNull(failure);
         }
 
         private void moveToNextShard() {
@@ -272,7 +282,7 @@ private void moveToNextShard() {
         }
 
         private void tryNext(@Nullable final Exception lastFailure, boolean canMatchShard) {
-            ShardRouting shardRouting = nextRoutingOrNull();
+            ShardRouting shardRouting = nextRoutingOrNull(lastFailure);
             if (shardRouting == null) {
                 if (canMatchShard == false) {
                     listener.onResponse(new FieldCapabilitiesIndexResponse(request.index(), Collections.emptyMap(), false));
@@ -336,6 +346,11 @@ public void handleException(TransportException exp) {
         }
     }
 
+    /**
+     * Shard transport handler for field capabilities index action
+     *
+     * @opensearch.internal
+     */
     private class ShardTransportHandler implements TransportRequestHandler<FieldCapabilitiesIndexRequest> {
         @Override
         public void messageReceived(final FieldCapabilitiesIndexRequest request, final TransportChannel channel, Task task)
diff --git a/server/src/main/java/org/opensearch/action/fieldcaps/package-info.java b/server/src/main/java/org/opensearch/action/fieldcaps/package-info.java
new file mode 100644
index 0000000000000..c7b7c01875d2b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/fieldcaps/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Field Capabilities transport handlers. */
+package org.opensearch.action.fieldcaps;
diff --git a/server/src/main/java/org/opensearch/action/get/GetAction.java b/server/src/main/java/org/opensearch/action/get/GetAction.java
index f90fbc9b3be1c..05544591f030e 100644
--- a/server/src/main/java/org/opensearch/action/get/GetAction.java
+++ b/server/src/main/java/org/opensearch/action/get/GetAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to get a document
+ *
+ * @opensearch.internal
+ */
 public class GetAction extends ActionType<GetResponse> {
 
     public static final GetAction INSTANCE = new GetAction();
diff --git a/server/src/main/java/org/opensearch/action/get/GetRequest.java b/server/src/main/java/org/opensearch/action/get/GetRequest.java
index 9badf2db92f67..83839e4ba3726 100644
--- a/server/src/main/java/org/opensearch/action/get/GetRequest.java
+++ b/server/src/main/java/org/opensearch/action/get/GetRequest.java
@@ -38,10 +38,10 @@
 import org.opensearch.action.RealtimeRequest;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -60,6 +60,8 @@
  * @see GetResponse
  * @see org.opensearch.client.Requests#getRequest(String)
  * @see org.opensearch.client.Client#get(GetRequest)
+ *
+ * @opensearch.internal
  */
 public class GetRequest extends SingleShardRequest<GetRequest> implements RealtimeRequest {
 
@@ -152,7 +154,8 @@ public GetRequest routing(String routing) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public GetRequest preference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/get/GetRequestBuilder.java b/server/src/main/java/org/opensearch/action/get/GetRequestBuilder.java
index 492a88b9d3821..6237cf73f0ca8 100644
--- a/server/src/main/java/org/opensearch/action/get/GetRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/get/GetRequestBuilder.java
@@ -35,12 +35,14 @@
 import org.opensearch.action.support.single.shard.SingleShardOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.VersionType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 
 /**
  * A get document action request builder.
+ *
+ * @opensearch.internal
  */
 public class GetRequestBuilder extends SingleShardOperationRequestBuilder<GetRequest, GetResponse, GetRequestBuilder> {
 
@@ -71,7 +73,8 @@ public GetRequestBuilder setRouting(String routing) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public GetRequestBuilder setPreference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/get/GetResponse.java b/server/src/main/java/org/opensearch/action/get/GetResponse.java
index a15607d696195..c86128444d7eb 100644
--- a/server/src/main/java/org/opensearch/action/get/GetResponse.java
+++ b/server/src/main/java/org/opensearch/action/get/GetResponse.java
@@ -33,16 +33,17 @@
 package org.opensearch.action.get;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 
 import java.io.IOException;
@@ -56,6 +57,8 @@
  *
  * @see GetRequest
  * @see org.opensearch.client.Client#get(GetRequest)
+ *
+ * @opensearch.internal
  */
 public class GetResponse extends ActionResponse implements Iterable<DocumentField>, ToXContentObject {
 
@@ -235,6 +238,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetAction.java b/server/src/main/java/org/opensearch/action/get/MultiGetAction.java
index f7df277585250..bed5d0bd9e55e 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetAction.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for a multi get
+ *
+ * @opensearch.internal
+ */
 public class MultiGetAction extends ActionType<MultiGetResponse> {
 
     public static final MultiGetAction INSTANCE = new MultiGetAction();
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetItemResponse.java b/server/src/main/java/org/opensearch/action/get/MultiGetItemResponse.java
index 1ff684fcc5872..19c9b785e7ea2 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetItemResponse.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetItemResponse.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
 /**
  * A single multi get response.
+ *
+ * @opensearch.internal
  */
 public class MultiGetItemResponse implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetRequest.java b/server/src/main/java/org/opensearch/action/get/MultiGetRequest.java
index 974799dd7bf4c..8ccf5afb9fe4c 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetRequest.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetRequest.java
@@ -43,17 +43,18 @@
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -66,6 +67,11 @@
 import java.util.List;
 import java.util.Locale;
 
+/**
+ * Transport request for a multi get.
+ *
+ * @opensearch.internal
+ */
 public class MultiGetRequest extends ActionRequest
     implements
         Iterable<MultiGetRequest.Item>,
@@ -85,6 +91,8 @@ public class MultiGetRequest extends ActionRequest
 
     /**
      * A single get item.
+     *
+     * @opensearch.internal
      */
     public static class Item implements Writeable, IndicesRequest, ToXContentObject {
 
@@ -260,7 +268,7 @@ public int hashCode() {
         }
 
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
     }
@@ -315,7 +323,8 @@ public ActionRequestValidationException validate() {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public MultiGetRequest preference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetRequestBuilder.java b/server/src/main/java/org/opensearch/action/get/MultiGetRequestBuilder.java
index 56ac6cbd1b8c9..c317edc07da8b 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetRequestBuilder.java
@@ -37,6 +37,8 @@
 
 /**
  * A multi get document action request builder.
+ *
+ * @opensearch.internal
  */
 public class MultiGetRequestBuilder extends ActionRequestBuilder<MultiGetRequest, MultiGetResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetResponse.java b/server/src/main/java/org/opensearch/action/get/MultiGetResponse.java
index ca6249861dd50..73372b85be3b2 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetResponse.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetResponse.java
@@ -34,15 +34,15 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.MapperService;
 
@@ -52,15 +52,26 @@
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Transport response for a multi get.
+ *
+ * @opensearch.internal
+ */
 public class MultiGetResponse extends ActionResponse implements Iterable<MultiGetItemResponse>, ToXContentObject {
 
     private static final ParseField INDEX = new ParseField("_index");
     private static final ParseField ID = new ParseField("_id");
     private static final ParseField ERROR = new ParseField("error");
     private static final ParseField DOCS = new ParseField("docs");
+    // In mixed clusters, the 1.x cluster could still return the '_type' in the response payload, it has to
+    // be handled gracefully
+    @Deprecated(forRemoval = true)
+    private static final ParseField TYPE = new ParseField("_type");
 
     /**
      * Represents a failure.
+     *
+     * @opensearch.internal
      */
     public static class Failure implements Writeable, ToXContentObject {
 
@@ -205,6 +216,7 @@ private static MultiGetItemResponse parseItem(XContentParser parser) throws IOEx
                     currentFieldName = parser.currentName();
                     if (INDEX.match(currentFieldName, parser.getDeprecationHandler()) == false
                         && ID.match(currentFieldName, parser.getDeprecationHandler()) == false
+                        && TYPE.match(currentFieldName, parser.getDeprecationHandler()) == false
                         && ERROR.match(currentFieldName, parser.getDeprecationHandler()) == false) {
                         getResult = GetResult.fromXContentEmbedded(parser, index, id);
                     }
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetShardRequest.java b/server/src/main/java/org/opensearch/action/get/MultiGetShardRequest.java
index 3f678d6db2407..c32b1da068e67 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetShardRequest.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetShardRequest.java
@@ -32,16 +32,20 @@
 
 package org.opensearch.action.get;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Multi get shards.
+ *
+ * @opensearch.internal
+ */
 public class MultiGetShardRequest extends SingleShardRequest<MultiGetShardRequest> {
 
     private int shardId;
@@ -49,13 +53,13 @@ public class MultiGetShardRequest extends SingleShardRequest<MultiGetShardReques
     private boolean realtime;
     private boolean refresh;
 
-    IntArrayList locations;
+    List<Integer> locations;
     List<MultiGetRequest.Item> items;
 
     MultiGetShardRequest(StreamInput in) throws IOException {
         super(in);
         int size = in.readVInt();
-        locations = new IntArrayList(size);
+        locations = new ArrayList<>(size);
         items = new ArrayList<>(size);
 
         for (int i = 0; i < size; i++) {
@@ -71,7 +75,7 @@ public class MultiGetShardRequest extends SingleShardRequest<MultiGetShardReques
     MultiGetShardRequest(MultiGetRequest multiGetRequest, String index, int shardId) {
         super(index);
         this.shardId = shardId;
-        locations = new IntArrayList();
+        locations = new ArrayList<>();
         items = new ArrayList<>();
         preference = multiGetRequest.preference;
         realtime = multiGetRequest.realtime;
@@ -89,7 +93,8 @@ public int shardId() {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public MultiGetShardRequest preference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/get/MultiGetShardResponse.java b/server/src/main/java/org/opensearch/action/get/MultiGetShardResponse.java
index 2393fa4749876..ca020e74c7d93 100644
--- a/server/src/main/java/org/opensearch/action/get/MultiGetShardResponse.java
+++ b/server/src/main/java/org/opensearch/action/get/MultiGetShardResponse.java
@@ -32,23 +32,27 @@
 
 package org.opensearch.action.get;
 
-import com.carrotsearch.hppc.IntArrayList;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Transport response for multi get shards.
+ *
+ * @opensearch.internal
+ */
 public class MultiGetShardResponse extends ActionResponse {
 
-    final IntArrayList locations;
+    final List<Integer> locations;
     final List<GetResponse> responses;
     final List<MultiGetResponse.Failure> failures;
 
     MultiGetShardResponse() {
-        locations = new IntArrayList();
+        locations = new ArrayList<>();
         responses = new ArrayList<>();
         failures = new ArrayList<>();
     }
@@ -56,7 +60,7 @@ public class MultiGetShardResponse extends ActionResponse {
     MultiGetShardResponse(StreamInput in) throws IOException {
         super(in);
         int size = in.readVInt();
-        locations = new IntArrayList(size);
+        locations = new ArrayList<>(size);
         responses = new ArrayList<>(size);
         failures = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
diff --git a/server/src/main/java/org/opensearch/action/get/TransportGetAction.java b/server/src/main/java/org/opensearch/action/get/TransportGetAction.java
index 999cc8c12190b..00a795c86356f 100644
--- a/server/src/main/java/org/opensearch/action/get/TransportGetAction.java
+++ b/server/src/main/java/org/opensearch/action/get/TransportGetAction.java
@@ -32,20 +32,22 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.single.shard.TransportSingleShardAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.Preference;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -54,6 +56,8 @@
 
 /**
  * Performs the get operation.
+ *
+ * @opensearch.internal
  */
 public class TransportGetAction extends TransportSingleShardAction<GetRequest, GetResponse> {
 
@@ -86,16 +90,30 @@ protected boolean resolveIndex(GetRequest request) {
         return true;
     }
 
+    /**
+     * Returns true if GET request should be routed to primary shards, else false.
+     */
+    protected static boolean shouldForcePrimaryRouting(Metadata metadata, boolean realtime, String preference, String indexName) {
+        return metadata.isSegmentReplicationEnabled(indexName) && realtime && preference == null;
+    }
+
     @Override
     protected ShardIterator shards(ClusterState state, InternalRequest request) {
+        final String preference;
+        // route realtime GET requests when segment replication is enabled to primary shards,
+        // iff there are no other preferences/routings enabled for routing to a specific shard
+        if (shouldForcePrimaryRouting(
+            state.getMetadata(),
+            request.request().realtime,
+            request.request().preference(),
+            request.concreteIndex()
+        )) {
+            preference = Preference.PRIMARY.type();
+        } else {
+            preference = request.request().preference();
+        }
         return clusterService.operationRouting()
-            .getShards(
-                clusterService.state(),
-                request.concreteIndex(),
-                request.request().id(),
-                request.request().routing(),
-                request.request().preference()
-            );
+            .getShards(clusterService.state(), request.concreteIndex(), request.request().id(), request.request().routing(), preference);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/get/TransportMultiGetAction.java b/server/src/main/java/org/opensearch/action/get/TransportMultiGetAction.java
index 33f1e559a072c..8bbfef381aea8 100644
--- a/server/src/main/java/org/opensearch/action/get/TransportMultiGetAction.java
+++ b/server/src/main/java/org/opensearch/action/get/TransportMultiGetAction.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.Preference;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -50,6 +52,11 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Perform the multi get action.
+ *
+ * @opensearch.internal
+ */
 public class TransportMultiGetAction extends HandledTransportAction<MultiGetRequest, MultiGetResponse> {
 
     private final ClusterService clusterService;
@@ -70,6 +77,10 @@ public TransportMultiGetAction(
         this.indexNameExpressionResolver = resolver;
     }
 
+    protected static boolean shouldForcePrimaryRouting(Metadata metadata, boolean realtime, String preference, String indexName) {
+        return metadata.isSegmentReplicationEnabled(indexName) && realtime && preference == null;
+    }
+
     @Override
     protected void doExecute(Task task, final MultiGetRequest request, final ActionListener<MultiGetResponse> listener) {
         ClusterState clusterState = clusterService.state();
@@ -104,6 +115,9 @@ protected void doExecute(Task task, final MultiGetRequest request, final ActionL
 
             MultiGetShardRequest shardRequest = shardRequests.get(shardId);
             if (shardRequest == null) {
+                if (shouldForcePrimaryRouting(clusterState.getMetadata(), request.realtime(), request.preference(), concreteSingleIndex)) {
+                    request.preference(Preference.PRIMARY.type());
+                }
                 shardRequest = new MultiGetShardRequest(request, shardId.getIndexName(), shardId.getId());
                 shardRequests.put(shardId, shardRequest);
             }
diff --git a/server/src/main/java/org/opensearch/action/get/TransportShardMultiGetAction.java b/server/src/main/java/org/opensearch/action/get/TransportShardMultiGetAction.java
index db35af9c3e20f..27955098d96cd 100644
--- a/server/src/main/java/org/opensearch/action/get/TransportShardMultiGetAction.java
+++ b/server/src/main/java/org/opensearch/action/get/TransportShardMultiGetAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.get;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.action.support.single.shard.TransportSingleShardAction;
@@ -42,17 +41,23 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
+/**
+ * Perform the shard multi get action
+ *
+ * @opensearch.internal
+ */
 public class TransportShardMultiGetAction extends TransportSingleShardAction<MultiGetShardRequest, MultiGetShardResponse> {
 
     private static final String ACTION_NAME = MultiGetAction.NAME + "[shard]";
diff --git a/server/src/main/java/org/opensearch/action/index/IndexAction.java b/server/src/main/java/org/opensearch/action/index/IndexAction.java
index 3f28af9b39d8a..0383cafba2958 100644
--- a/server/src/main/java/org/opensearch/action/index/IndexAction.java
+++ b/server/src/main/java/org/opensearch/action/index/IndexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for indexing a document.
+ *
+ * @opensearch.internal
+ */
 public class IndexAction extends ActionType<IndexResponse> {
 
     public static final IndexAction INSTANCE = new IndexAction();
diff --git a/server/src/main/java/org/opensearch/action/index/IndexRequest.java b/server/src/main/java/org/opensearch/action/index/IndexRequest.java
index 7bf6b876fa652..2500496103415 100644
--- a/server/src/main/java/org/opensearch/action/index/IndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/index/IndexRequest.java
@@ -48,22 +48,23 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
@@ -77,17 +78,19 @@
  * created using {@link org.opensearch.client.Requests#indexRequest(String)}.
  *
  * The index requires the {@link #index()}, {@link #id(String)} and
- * {@link #source(byte[], XContentType)} to be set.
+ * {@link #source(byte[], MediaType)} to be set.
  *
- * The source (content to index) can be set in its bytes form using ({@link #source(byte[], XContentType)}),
- * its string form ({@link #source(String, XContentType)}) or using a {@link org.opensearch.common.xcontent.XContentBuilder}
- * ({@link #source(org.opensearch.common.xcontent.XContentBuilder)}).
+ * The source (content to index) can be set in its bytes form using ({@link #source(byte[], MediaType)}),
+ * its string form ({@link #source(String, MediaType)}) or using a {@link XContentBuilder}
+ * ({@link #source(XContentBuilder)}).
  *
  * If the {@link #id(String)} is not set, it will be automatically generated.
  *
  * @see IndexResponse
  * @see org.opensearch.client.Requests#indexRequest(String)
  * @see org.opensearch.client.Client#index(IndexRequest)
+ *
+ * @opensearch.internal
  */
 public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implements DocWriteRequest<IndexRequest>, CompositeIndicesRequest {
 
@@ -113,7 +116,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
     private long version = Versions.MATCH_ANY;
     private VersionType versionType = VersionType.INTERNAL;
 
-    private XContentType contentType;
+    private MediaType contentType;
 
     private String pipeline;
     private String finalPipeline;
@@ -163,7 +166,11 @@ public IndexRequest(@Nullable ShardId shardId, StreamInput in) throws IOExceptio
         isRetry = in.readBoolean();
         autoGeneratedTimestamp = in.readLong();
         if (in.readBoolean()) {
-            contentType = in.readEnum(XContentType.class);
+            if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                contentType = in.readMediaType();
+            } else {
+                contentType = in.readEnum(XContentType.class);
+            }
         } else {
             contentType = null;
         }
@@ -182,7 +189,7 @@ public IndexRequest() {
 
     /**
      * Constructs a new index request against the specific index. The
-     * {@link #source(byte[], XContentType)} must be set.
+     * {@link #source(byte[], MediaType)} must be set.
      */
     public IndexRequest(String index) {
         super(NO_SHARD_ID);
@@ -235,12 +242,7 @@ public ActionRequestValidationException validate() {
 
         validationException = DocWriteRequest.validateSeqNoBasedCASParams(this, validationException);
 
-        if (id != null && id.getBytes(StandardCharsets.UTF_8).length > 512) {
-            validationException = addValidationError(
-                "id [" + id + "] is too long, must be no longer than 512 bytes but was: " + id.getBytes(StandardCharsets.UTF_8).length,
-                validationException
-            );
-        }
+        validationException = DocWriteRequest.validateDocIdLength(id, validationException);
 
         if (pipeline != null && pipeline.isEmpty()) {
             validationException = addValidationError("pipeline cannot be an empty string", validationException);
@@ -262,7 +264,7 @@ public IndicesOptions indicesOptions() {
      * The content type. This will be used when generating a document from user provided objects like Maps and when parsing the
      * source at index time
      */
-    public XContentType getContentType() {
+    public MediaType getContentType() {
         return contentType;
     }
 
@@ -385,9 +387,9 @@ public IndexRequest source(Map<String, ?> source) throws OpenSearchGenerationExc
      *
      * @param source The map to index
      */
-    public IndexRequest source(Map<String, ?> source, XContentType contentType) throws OpenSearchGenerationException {
+    public IndexRequest source(Map<String, ?> source, MediaType contentType) throws OpenSearchGenerationException {
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(contentType);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(contentType);
             builder.map(source);
             return source(builder);
         } catch (IOException e) {
@@ -398,11 +400,11 @@ public IndexRequest source(Map<String, ?> source, XContentType contentType) thro
     /**
      * Sets the document source to index.
      *
-     * Note, its preferable to either set it using {@link #source(org.opensearch.common.xcontent.XContentBuilder)}
-     * or using the {@link #source(byte[], XContentType)}.
+     * Note, its preferable to either set it using {@link #source(XContentBuilder)}
+     * or using the {@link #source(byte[], MediaType)}.
      */
-    public IndexRequest source(String source, XContentType xContentType) {
-        return source(new BytesArray(source), xContentType);
+    public IndexRequest source(String source, MediaType mediaType) {
+        return source(new BytesArray(source), mediaType);
     }
 
     /**
@@ -432,7 +434,7 @@ public IndexRequest source(Object... source) {
      * valid String representation.</b>
      * </p>
      */
-    public IndexRequest source(XContentType xContentType, Object... source) {
+    public IndexRequest source(MediaType mediaType, Object... source) {
         if (source.length % 2 != 0) {
             throw new IllegalArgumentException("The number of object passed must be even but was [" + source.length + "]");
         }
@@ -443,7 +445,7 @@ public IndexRequest source(XContentType xContentType, Object... source) {
             );
         }
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(mediaType);
             builder.startObject();
             for (int i = 0; i < source.length; i++) {
                 builder.field(source[i++].toString(), source[i]);
@@ -458,29 +460,30 @@ public IndexRequest source(XContentType xContentType, Object... source) {
     /**
      * Sets the document to index in bytes form.
      */
-    public IndexRequest source(BytesReference source, XContentType xContentType) {
+    public IndexRequest source(BytesReference source, MediaType mediaType) {
         this.source = Objects.requireNonNull(source);
-        this.contentType = Objects.requireNonNull(xContentType);
+        this.contentType = Objects.requireNonNull(mediaType);
         return this;
     }
 
     /**
      * Sets the document to index in bytes form.
      */
-    public IndexRequest source(byte[] source, XContentType xContentType) {
-        return source(source, 0, source.length, xContentType);
+    public IndexRequest source(byte[] source, MediaType mediaType) {
+        return source(source, 0, source.length, mediaType);
     }
 
     /**
      * Sets the document to index in bytes form (assumed to be safe to be used from different
      * threads).
      *
-     * @param source The source to index
-     * @param offset The offset in the byte array
-     * @param length The length of the data
+     * @param source    The source to index
+     * @param offset    The offset in the byte array
+     * @param length    The length of the data
+     * @param mediaType The data format over the wire
      */
-    public IndexRequest source(byte[] source, int offset, int length, XContentType xContentType) {
-        return source(new BytesArray(source, offset, length), xContentType);
+    public IndexRequest source(byte[] source, int offset, int length, MediaType mediaType) {
+        return source(new BytesArray(source, offset, length), mediaType);
     }
 
     /**
@@ -685,7 +688,11 @@ private void writeBody(StreamOutput out) throws IOException {
         out.writeLong(autoGeneratedTimestamp);
         if (contentType != null) {
             out.writeBoolean(true);
-            out.writeEnum(contentType);
+            if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                contentType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) contentType);
+            }
         } else {
             out.writeBoolean(false);
         }
@@ -698,7 +705,7 @@ private void writeBody(StreamOutput out) throws IOException {
 
     @Override
     public String toString() {
-        String sSource = "_na_";
+        String sSource = Strings.UNKNOWN_UUID_VALUE;
         try {
             if (source.length() > MAX_SOURCE_LENGTH_IN_TOSTRING) {
                 sSource = "n/a, actual length: ["
diff --git a/server/src/main/java/org/opensearch/action/index/IndexRequestBuilder.java b/server/src/main/java/org/opensearch/action/index/IndexRequestBuilder.java
index cef5ef0f85c62..4bf7634dcb7e1 100644
--- a/server/src/main/java/org/opensearch/action/index/IndexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/index/IndexRequestBuilder.java
@@ -37,15 +37,17 @@
 import org.opensearch.action.support.replication.ReplicationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 
 import java.util.Map;
 
 /**
  * An index document action request builder.
+ *
+ * @opensearch.internal
  */
 public class IndexRequestBuilder extends ReplicationRequestBuilder<IndexRequest, IndexResponse, IndexRequestBuilder>
     implements
@@ -80,8 +82,8 @@ public IndexRequestBuilder setRouting(String routing) {
     /**
      * Sets the source.
      */
-    public IndexRequestBuilder setSource(BytesReference source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public IndexRequestBuilder setSource(BytesReference source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
@@ -100,7 +102,7 @@ public IndexRequestBuilder setSource(Map<String, ?> source) {
      *
      * @param source The map to index
      */
-    public IndexRequestBuilder setSource(Map<String, ?> source, XContentType contentType) {
+    public IndexRequestBuilder setSource(Map<String, ?> source, MediaType contentType) {
         request.source(source, contentType);
         return this;
     }
@@ -108,11 +110,11 @@ public IndexRequestBuilder setSource(Map<String, ?> source, XContentType content
     /**
      * Sets the document source to index.
      * <p>
-     * Note, its preferable to either set it using {@link #setSource(org.opensearch.common.xcontent.XContentBuilder)}
-     * or using the {@link #setSource(byte[], XContentType)}.
+     * Note, its preferable to either set it using {@link #setSource(XContentBuilder)}
+     * or using the {@link #setSource(byte[], MediaType)}.
      */
-    public IndexRequestBuilder setSource(String source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public IndexRequestBuilder setSource(String source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
@@ -127,8 +129,8 @@ public IndexRequestBuilder setSource(XContentBuilder sourceBuilder) {
     /**
      * Sets the document to index in bytes form.
      */
-    public IndexRequestBuilder setSource(byte[] source, XContentType xContentType) {
-        request.source(source, xContentType);
+    public IndexRequestBuilder setSource(byte[] source, MediaType mediaType) {
+        request.source(source, mediaType);
         return this;
     }
 
@@ -139,10 +141,10 @@ public IndexRequestBuilder setSource(byte[] source, XContentType xContentType) {
      * @param source The source to index
      * @param offset The offset in the byte array
      * @param length The length of the data
-     * @param xContentType The type/format of the source
+     * @param mediaType The type/format of the source
      */
-    public IndexRequestBuilder setSource(byte[] source, int offset, int length, XContentType xContentType) {
-        request.source(source, offset, length, xContentType);
+    public IndexRequestBuilder setSource(byte[] source, int offset, int length, MediaType mediaType) {
+        request.source(source, offset, length, mediaType);
         return this;
     }
 
@@ -167,8 +169,8 @@ public IndexRequestBuilder setSource(Object... source) {
      * valid String representation.</b>
      * </p>
      */
-    public IndexRequestBuilder setSource(XContentType xContentType, Object... source) {
-        request.source(xContentType, source);
+    public IndexRequestBuilder setSource(MediaType mediaType, Object... source) {
+        request.source(mediaType, source);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/index/IndexResponse.java b/server/src/main/java/org/opensearch/action/index/IndexResponse.java
index be0826ce84f96..d0aa9b57b6528 100644
--- a/server/src/main/java/org/opensearch/action/index/IndexResponse.java
+++ b/server/src/main/java/org/opensearch/action/index/IndexResponse.java
@@ -33,21 +33,24 @@
 package org.opensearch.action.index;
 
 import org.opensearch.action.DocWriteResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A response of an index operation,
  *
  * @see IndexRequest
  * @see org.opensearch.client.Client#index(IndexRequest)
+ *
+ * @opensearch.internal
  */
 public class IndexResponse extends DocWriteResponse {
 
@@ -87,7 +90,7 @@ public String toString() {
         builder.append(",result=").append(getResult().getLowercase());
         builder.append(",seqNo=").append(getSeqNo());
         builder.append(",primaryTerm=").append(getPrimaryTerm());
-        builder.append(",shards=").append(Strings.toString(getShardInfo()));
+        builder.append(",shards=").append(Strings.toString(MediaTypeRegistry.JSON, getShardInfo()));
         return builder.append("]").toString();
     }
 
@@ -112,6 +115,8 @@ public static void parseXContentFields(XContentParser parser, Builder context) t
      * Builder class for {@link IndexResponse}. This builder is usually used during xcontent parsing to
      * temporarily store the parsed values, then the {@link Builder#build()} method is called to
      * instantiate the {@link IndexResponse}.
+     *
+     * @opensearch.internal
      */
     public static class Builder extends DocWriteResponse.Builder {
         @Override
diff --git a/server/src/main/java/org/opensearch/action/index/TransportIndexAction.java b/server/src/main/java/org/opensearch/action/index/TransportIndexAction.java
index dcee695620498..fe4f80bf0c065 100644
--- a/server/src/main/java/org/opensearch/action/index/TransportIndexAction.java
+++ b/server/src/main/java/org/opensearch/action/index/TransportIndexAction.java
@@ -49,6 +49,8 @@
  * </ul>
  *
  * Deprecated use TransportBulkAction with a single item instead
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public class TransportIndexAction extends TransportSingleItemBulkWriteAction<IndexRequest, IndexResponse> {
diff --git a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineAction.java b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineAction.java
index 5ea978db3d5d4..6017be9747912 100644
--- a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action to delete a pipeline
+ *
+ * @opensearch.internal
+ */
 public class DeletePipelineAction extends ActionType<AcknowledgedResponse> {
 
     public static final DeletePipelineAction INSTANCE = new DeletePipelineAction();
diff --git a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequest.java
index 98bc125ce40dc..2f05ce3a25320 100644
--- a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequest.java
@@ -34,12 +34,17 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * transport request to delete a pipeline
+ *
+ * @opensearch.internal
+ */
 public class DeletePipelineRequest extends AcknowledgedRequest<DeletePipelineRequest> {
 
     private String id;
diff --git a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequestBuilder.java b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequestBuilder.java
index 53b5080f414e0..6a2eb494e8d3f 100644
--- a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineRequestBuilder.java
@@ -36,6 +36,11 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder to delete a pipeline
+ *
+ * @opensearch.internal
+ */
 public class DeletePipelineRequestBuilder extends ActionRequestBuilder<DeletePipelineRequest, AcknowledgedResponse> {
 
     public DeletePipelineRequestBuilder(OpenSearchClient client, DeletePipelineAction action) {
diff --git a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineTransportAction.java b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineTransportAction.java
index de2cf1ca74254..fe68f06d0d32e 100644
--- a/server/src/main/java/org/opensearch/action/ingest/DeletePipelineTransportAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/DeletePipelineTransportAction.java
@@ -32,23 +32,28 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class DeletePipelineTransportAction extends TransportMasterNodeAction<DeletePipelineRequest, AcknowledgedResponse> {
+/**
+ * Perform the action of deleting a pipeline
+ *
+ * @opensearch.internal
+ */
+public class DeletePipelineTransportAction extends TransportClusterManagerNodeAction<DeletePipelineRequest, AcknowledgedResponse> {
 
     private final IngestService ingestService;
 
@@ -83,7 +88,7 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(DeletePipelineRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
+    protected void clusterManagerOperation(DeletePipelineRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
         throws Exception {
         ingestService.delete(request, listener);
     }
diff --git a/server/src/main/java/org/opensearch/action/ingest/GetPipelineAction.java b/server/src/main/java/org/opensearch/action/ingest/GetPipelineAction.java
index 33b9d8f09d053..8371d82b8911e 100644
--- a/server/src/main/java/org/opensearch/action/ingest/GetPipelineAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/GetPipelineAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to get a pipeline
+ *
+ * @opensearch.internal
+ */
 public class GetPipelineAction extends ActionType<GetPipelineResponse> {
 
     public static final GetPipelineAction INSTANCE = new GetPipelineAction();
diff --git a/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequest.java
index 322fd1b8e1a52..4bae98098777d 100644
--- a/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequest.java
@@ -33,14 +33,19 @@
 package org.opensearch.action.ingest;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
-public class GetPipelineRequest extends MasterNodeReadRequest<GetPipelineRequest> {
+/**
+ * transport request to get a pipeline
+ *
+ * @opensearch.internal
+ */
+public class GetPipelineRequest extends ClusterManagerNodeReadRequest<GetPipelineRequest> {
 
     private String[] ids;
 
diff --git a/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequestBuilder.java b/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequestBuilder.java
index 45d9abc6b0adc..bdc13523ffdc6 100644
--- a/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/ingest/GetPipelineRequestBuilder.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
-public class GetPipelineRequestBuilder extends MasterNodeReadOperationRequestBuilder<
+/**
+ * Transport request builder to get a pipeline
+ *
+ * @opensearch.internal
+ */
+public class GetPipelineRequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<
     GetPipelineRequest,
     GetPipelineResponse,
     GetPipelineRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/action/ingest/GetPipelineResponse.java b/server/src/main/java/org/opensearch/action/ingest/GetPipelineResponse.java
index bf7dd909e390b..bd1b18be9a828 100644
--- a/server/src/main/java/org/opensearch/action/ingest/GetPipelineResponse.java
+++ b/server/src/main/java/org/opensearch/action/ingest/GetPipelineResponse.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.ingest.PipelineConfiguration;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -51,8 +52,13 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * transport response for getting a pipeline
+ *
+ * @opensearch.internal
+ */
 public class GetPipelineResponse extends ActionResponse implements StatusToXContentObject {
 
     private List<PipelineConfiguration> pipelines;
@@ -140,7 +146,12 @@ public boolean equals(Object other) {
             GetPipelineResponse otherResponse = (GetPipelineResponse) other;
             if (pipelines == null) {
                 return otherResponse.pipelines == null;
+            } else if (otherResponse.pipelines == null) {
+                return false;
             } else {
+                if (otherResponse.pipelines.size() != pipelines.size()) {
+                    return false;
+                }
                 // We need a map here because order does not matter for equality
                 Map<String, PipelineConfiguration> otherPipelineMap = new HashMap<>();
                 for (PipelineConfiguration pipeline : otherResponse.pipelines) {
@@ -161,7 +172,7 @@ public boolean equals(Object other) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/ingest/GetPipelineTransportAction.java b/server/src/main/java/org/opensearch/action/ingest/GetPipelineTransportAction.java
index a62201d097d12..80333c7346f92 100644
--- a/server/src/main/java/org/opensearch/action/ingest/GetPipelineTransportAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/GetPipelineTransportAction.java
@@ -32,23 +32,28 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
-public class GetPipelineTransportAction extends TransportMasterNodeReadAction<GetPipelineRequest, GetPipelineResponse> {
+/**
+ * Perform the action of getting a pipeline
+ *
+ * @opensearch.internal
+ */
+public class GetPipelineTransportAction extends TransportClusterManagerNodeReadAction<GetPipelineRequest, GetPipelineResponse> {
 
     @Inject
     public GetPipelineTransportAction(
@@ -80,7 +85,7 @@ protected GetPipelineResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(GetPipelineRequest request, ClusterState state, ActionListener<GetPipelineResponse> listener)
+    protected void clusterManagerOperation(GetPipelineRequest request, ClusterState state, ActionListener<GetPipelineResponse> listener)
         throws Exception {
         listener.onResponse(new GetPipelineResponse(IngestService.getPipelines(state, request.getIds())));
     }
diff --git a/server/src/main/java/org/opensearch/action/ingest/IngestActionForwarder.java b/server/src/main/java/org/opensearch/action/ingest/IngestActionForwarder.java
index 3ab3e3367fc6d..9927affbc7442 100644
--- a/server/src/main/java/org/opensearch/action/ingest/IngestActionForwarder.java
+++ b/server/src/main/java/org/opensearch/action/ingest/IngestActionForwarder.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionType;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Randomness;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.transport.TransportService;
 
 import java.util.concurrent.atomic.AtomicInteger;
@@ -48,6 +48,8 @@
  * A utility for forwarding ingest requests to ingest nodes in a round-robin fashion.
  *
  * TODO: move this into IngestService and make index/bulk actions call that
+ *
+ * @opensearch.internal
  */
 public final class IngestActionForwarder implements ClusterStateApplier {
 
@@ -80,6 +82,6 @@ private DiscoveryNode randomIngestNode() {
 
     @Override
     public void applyClusterState(ClusterChangedEvent event) {
-        ingestNodes = event.state().getNodes().getIngestNodes().values().toArray(DiscoveryNode.class);
+        ingestNodes = event.state().getNodes().getIngestNodes().values().toArray(new DiscoveryNode[0]);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/ingest/PutPipelineAction.java b/server/src/main/java/org/opensearch/action/ingest/PutPipelineAction.java
index d61a1ae1041cb..1fcbd783d246b 100644
--- a/server/src/main/java/org/opensearch/action/ingest/PutPipelineAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/PutPipelineAction.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 
+/**
+ * Transport action to put a new pipeline
+ *
+ * @opensearch.internal
+ */
 public class PutPipelineAction extends ActionType<AcknowledgedResponse> {
 
     public static final PutPipelineAction INSTANCE = new PutPipelineAction();
diff --git a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
index 526da7c4a74dc..f764e4b23860a 100644
--- a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
@@ -32,38 +32,49 @@
 
 package org.opensearch.action.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * transport request to put a pipeline
+ *
+ * @opensearch.internal
+ */
 public class PutPipelineRequest extends AcknowledgedRequest<PutPipelineRequest> implements ToXContentObject {
 
     private String id;
     private BytesReference source;
-    private XContentType xContentType;
+    private MediaType mediaType;
 
     /**
      * Create a new pipeline request with the id and source along with the content type of the source
      */
-    public PutPipelineRequest(String id, BytesReference source, XContentType xContentType) {
+    public PutPipelineRequest(String id, BytesReference source, MediaType mediaType) {
         this.id = Objects.requireNonNull(id);
         this.source = Objects.requireNonNull(source);
-        this.xContentType = Objects.requireNonNull(xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
     }
 
     public PutPipelineRequest(StreamInput in) throws IOException {
         super(in);
         id = in.readString();
         source = in.readBytesReference();
-        xContentType = in.readEnum(XContentType.class);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
     }
 
     PutPipelineRequest() {}
@@ -81,8 +92,8 @@ public BytesReference getSource() {
         return source;
     }
 
-    public XContentType getXContentType() {
-        return xContentType;
+    public MediaType getMediaType() {
+        return mediaType;
     }
 
     @Override
@@ -90,13 +101,17 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeString(id);
         out.writeBytesReference(source);
-        out.writeEnum(xContentType);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (source != null) {
-            builder.rawValue(source.streamInput(), xContentType);
+            builder.rawValue(source.streamInput(), mediaType);
         } else {
             builder.startObject().endObject();
         }
diff --git a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequestBuilder.java b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequestBuilder.java
index 8279e2f3756e9..e734abb6d7969 100644
--- a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequestBuilder.java
@@ -35,9 +35,14 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 
+/**
+ * Transport request builder to put a pipeline
+ *
+ * @opensearch.internal
+ */
 public class PutPipelineRequestBuilder extends ActionRequestBuilder<PutPipelineRequest, AcknowledgedResponse> {
 
     public PutPipelineRequestBuilder(OpenSearchClient client, PutPipelineAction action) {
@@ -49,8 +54,8 @@ public PutPipelineRequestBuilder(
         PutPipelineAction action,
         String id,
         BytesReference source,
-        XContentType xContentType
+        MediaType mediaType
     ) {
-        super(client, action, new PutPipelineRequest(id, source, xContentType));
+        super(client, action, new PutPipelineRequest(id, source, mediaType));
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/ingest/PutPipelineTransportAction.java b/server/src/main/java/org/opensearch/action/ingest/PutPipelineTransportAction.java
index 89d1c1efed8a6..e2d206e8c4f6d 100644
--- a/server/src/main/java/org/opensearch/action/ingest/PutPipelineTransportAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/PutPipelineTransportAction.java
@@ -32,12 +32,11 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoRequest;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
 import org.opensearch.client.OriginSettingClient;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterState;
@@ -46,7 +45,8 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.ingest.IngestInfo;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.threadpool.ThreadPool;
@@ -58,7 +58,12 @@
 
 import static org.opensearch.ingest.IngestService.INGEST_ORIGIN;
 
-public class PutPipelineTransportAction extends TransportMasterNodeAction<PutPipelineRequest, AcknowledgedResponse> {
+/**
+ * Perform the action of putting a pipeline
+ *
+ * @opensearch.internal
+ */
+public class PutPipelineTransportAction extends TransportClusterManagerNodeAction<PutPipelineRequest, AcknowledgedResponse> {
 
     private final IngestService ingestService;
     private final OriginSettingClient client;
@@ -98,7 +103,7 @@ protected AcknowledgedResponse read(StreamInput in) throws IOException {
     }
 
     @Override
-    protected void masterOperation(PutPipelineRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
+    protected void clusterManagerOperation(PutPipelineRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
         throws Exception {
         NodesInfoRequest nodesInfoRequest = new NodesInfoRequest();
         nodesInfoRequest.clear().addMetric(NodesInfoRequest.Metric.INGEST.metricName());
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentBaseResult.java b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentBaseResult.java
index 10ccb2003969d..cb0c5f551d627 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentBaseResult.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentBaseResult.java
@@ -33,20 +33,22 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.IngestDocument;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Holds the end result of what a pipeline did to sample document provided via the simulate api.
+ *
+ *
  */
 public final class SimulateDocumentBaseResult implements SimulateDocumentResult {
     private final WriteableIngestDocument ingestDocument;
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentResult.java b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentResult.java
index 3beaf43d2a1ae..98a03272aff42 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentResult.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentResult.java
@@ -31,9 +31,14 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
 
+/**
+ * Interface to simulate a document result
+ *
+ * @opensearch.internal
+ */
 public interface SimulateDocumentResult extends Writeable, ToXContentObject {
 
 }
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentVerboseResult.java b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentVerboseResult.java
index 07d9b628fe35d..f26bb106de273 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentVerboseResult.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulateDocumentVerboseResult.java
@@ -31,22 +31,24 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Holds the result of what a pipeline did to a sample document via the simulate api, but instead of {@link SimulateDocumentBaseResult}
  * this result class holds the intermediate result each processor did to the sample document.
+ *
+ * @opensearch.internal
  */
 public final class SimulateDocumentVerboseResult implements SimulateDocumentResult {
     public static final String PROCESSOR_RESULT_FIELD = "processor_results";
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulateExecutionService.java b/server/src/main/java/org/opensearch/action/ingest/SimulateExecutionService.java
index 8c620c707b3ac..c7c0f21eb0876 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulateExecutionService.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulateExecutionService.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.ingest.CompoundProcessor;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Pipeline;
@@ -46,6 +46,11 @@
 
 import static org.opensearch.ingest.TrackingResultProcessor.decorate;
 
+/**
+ * Service to simulate pipeline execution
+ *
+ * @opensearch.internal
+ */
 class SimulateExecutionService {
 
     private static final String THREAD_POOL_NAME = ThreadPool.Names.MANAGEMENT;
@@ -71,10 +76,9 @@ void executeDocument(
                 pipeline.getVersion(),
                 verbosePipelineProcessor
             );
-            ingestDocument.executePipeline(
-                verbosePipeline,
-                (result, e) -> { handler.accept(new SimulateDocumentVerboseResult(processorResultList), e); }
-            );
+            ingestDocument.executePipeline(verbosePipeline, (result, e) -> {
+                handler.accept(new SimulateDocumentVerboseResult(processorResultList), e);
+            });
         } else {
             ingestDocument.executePipeline(pipeline, (result, e) -> {
                 if (e == null) {
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineAction.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineAction.java
index 8039a83b5953e..df2cfda778d06 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action to simulate a pipeline
+ *
+ * @opensearch.internal
+ */
 public class SimulatePipelineAction extends ActionType<SimulatePipelineResponse> {
 
     public static final SimulatePipelineAction INSTANCE = new SimulatePipelineAction();
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
index bc0317e076319..2234934499609 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.action.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
@@ -55,20 +57,25 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * transport request to simulate a pipeline
+ *
+ * @opensearch.internal
+ */
 public class SimulatePipelineRequest extends ActionRequest implements ToXContentObject {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(SimulatePipelineRequest.class);
     private String id;
     private boolean verbose;
     private BytesReference source;
-    private XContentType xContentType;
+    private MediaType mediaType;
 
     /**
      * Creates a new request with the given source and its content type
      */
-    public SimulatePipelineRequest(BytesReference source, XContentType xContentType) {
+    public SimulatePipelineRequest(BytesReference source, MediaType mediaType) {
         this.source = Objects.requireNonNull(source);
-        this.xContentType = Objects.requireNonNull(xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
     }
 
     SimulatePipelineRequest() {}
@@ -78,7 +85,11 @@ public SimulatePipelineRequest(BytesReference source, XContentType xContentType)
         id = in.readOptionalString();
         verbose = in.readBoolean();
         source = in.readBytesReference();
-        xContentType = in.readEnum(XContentType.class);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
     }
 
     @Override
@@ -106,8 +117,8 @@ public BytesReference getSource() {
         return source;
     }
 
-    public XContentType getXContentType() {
-        return xContentType;
+    public MediaType getXContentType() {
+        return mediaType;
     }
 
     @Override
@@ -116,15 +127,24 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalString(id);
         out.writeBoolean(verbose);
         out.writeBytesReference(source);
-        out.writeEnum(xContentType);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        builder.rawValue(source.streamInput(), xContentType);
+        builder.rawValue(source.streamInput(), mediaType);
         return builder;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     public static final class Fields {
         static final String PIPELINE = "pipeline";
         static final String DOCS = "docs";
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequestBuilder.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequestBuilder.java
index 6befbea774685..55e6d95fde65c 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequestBuilder.java
@@ -34,9 +34,14 @@
 
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 
+/**
+ * Transport request builder to simulate a pipeline
+ *
+ * @opensearch.internal
+ */
 public class SimulatePipelineRequestBuilder extends ActionRequestBuilder<SimulatePipelineRequest, SimulatePipelineResponse> {
 
     /**
@@ -53,9 +58,9 @@ public SimulatePipelineRequestBuilder(
         OpenSearchClient client,
         SimulatePipelineAction action,
         BytesReference source,
-        XContentType xContentType
+        MediaType mediaType
     ) {
-        super(client, action, new SimulatePipelineRequest(source, xContentType));
+        super(client, action, new SimulatePipelineRequest(source, mediaType));
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineResponse.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineResponse.java
index c3540e4e9b8fd..3cbbc4350c3bd 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineResponse.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineResponse.java
@@ -33,24 +33,29 @@
 package org.opensearch.action.ingest;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * transport response for simulating a pipeline
+ *
+ * @opensearch.internal
+ */
 public class SimulatePipelineResponse extends ActionResponse implements ToXContentObject {
     private String pipelineId;
     private boolean verbose;
@@ -173,6 +178,11 @@ public static SimulatePipelineResponse fromXContent(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String DOCUMENTS = "docs";
     }
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineTransportAction.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineTransportAction.java
index 7348035deaafe..4753679d370af 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineTransportAction.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineTransportAction.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -45,6 +45,11 @@
 
 import java.util.Map;
 
+/**
+ * Perform the action of simulating a pipeline
+ *
+ * @opensearch.internal
+ */
 public class SimulatePipelineTransportAction extends HandledTransportAction<SimulatePipelineRequest, SimulatePipelineResponse> {
 
     private final IngestService ingestService;
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulateProcessorResult.java b/server/src/main/java/org/opensearch/action/ingest/SimulateProcessorResult.java
index eae36cc4efd7c..d933877fa214d 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulateProcessorResult.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulateProcessorResult.java
@@ -33,24 +33,29 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
 
 import java.io.IOException;
 import java.util.Locale;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Simulates an ingest processor result
+ *
+ * @opensearch.internal
+ */
 public class SimulateProcessorResult implements Writeable, ToXContentObject {
 
     private static final String IGNORED_ERROR_FIELD = "ignored_error";
diff --git a/server/src/main/java/org/opensearch/action/ingest/WriteableIngestDocument.java b/server/src/main/java/org/opensearch/action/ingest/WriteableIngestDocument.java
index 2f8c65486c22f..f8cc4736e87b0 100644
--- a/server/src/main/java/org/opensearch/action/ingest/WriteableIngestDocument.java
+++ b/server/src/main/java/org/opensearch/action/ingest/WriteableIngestDocument.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.IngestDocument.Metadata;
 
@@ -49,9 +49,14 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * An ingest document that implements writeable
+ *
+ * @opensearch.internal
+ */
 final class WriteableIngestDocument implements Writeable, ToXContentFragment {
 
     static final String SOURCE_FIELD = "_source";
diff --git a/server/src/main/java/org/opensearch/action/ingest/package-info.java b/server/src/main/java/org/opensearch/action/ingest/package-info.java
new file mode 100644
index 0000000000000..42414f2090b41
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/ingest/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Ingest API transport handlers. */
+package org.opensearch.action.ingest;
diff --git a/server/src/main/java/org/opensearch/action/main/MainAction.java b/server/src/main/java/org/opensearch/action/main/MainAction.java
index 46de6f9e2b0f0..c5cbac824ec83 100644
--- a/server/src/main/java/org/opensearch/action/main/MainAction.java
+++ b/server/src/main/java/org/opensearch/action/main/MainAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * The main OpenSearch Action
+ *
+ * @opensearch.internal
+ */
 public class MainAction extends ActionType<MainResponse> {
 
     public static final String NAME = "cluster:monitor/main";
diff --git a/server/src/main/java/org/opensearch/action/main/MainRequest.java b/server/src/main/java/org/opensearch/action/main/MainRequest.java
index f5cafecb87375..459633fa63cb3 100644
--- a/server/src/main/java/org/opensearch/action/main/MainRequest.java
+++ b/server/src/main/java/org/opensearch/action/main/MainRequest.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for main action
+ *
+ * @opensearch.internal
+ */
 public class MainRequest extends ActionRequest {
 
     public MainRequest() {}
diff --git a/server/src/main/java/org/opensearch/action/main/MainRequestBuilder.java b/server/src/main/java/org/opensearch/action/main/MainRequestBuilder.java
index 8f73f316194ba..bd62882551c44 100644
--- a/server/src/main/java/org/opensearch/action/main/MainRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/main/MainRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Transport request builder for the main opensearch action
+ *
+ * @opensearch.internal
+ */
 public class MainRequestBuilder extends ActionRequestBuilder<MainRequest, MainResponse> {
 
     public MainRequestBuilder(OpenSearchClient client, MainAction action) {
diff --git a/server/src/main/java/org/opensearch/action/main/MainResponse.java b/server/src/main/java/org/opensearch/action/main/MainResponse.java
index bd4be885fa210..254384a04f64f 100644
--- a/server/src/main/java/org/opensearch/action/main/MainResponse.java
+++ b/server/src/main/java/org/opensearch/action/main/MainResponse.java
@@ -35,19 +35,24 @@
 import org.opensearch.Build;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * The main response of opensearch
+ *
+ * @opensearch.internal
+ */
 public class MainResponse extends ActionResponse implements ToXContentObject {
 
     private String nodeName;
@@ -63,10 +68,10 @@ public class MainResponse extends ActionResponse implements ToXContentObject {
     MainResponse(StreamInput in) throws IOException {
         super(in);
         nodeName = in.readString();
-        version = Version.readVersion(in);
+        version = in.readVersion();
         clusterName = new ClusterName(in);
         clusterUuid = in.readString();
-        build = Build.readBuild(in);
+        build = in.readBuild();
         if (in.getVersion().before(LegacyESVersion.V_7_0_0)) {
             in.readBoolean();
         }
@@ -119,13 +124,13 @@ public String getVersionNumber() {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(nodeName);
         if (out.getVersion().before(Version.V_1_0_0)) {
-            Version.writeVersion(LegacyESVersion.V_7_10_2, out);
+            out.writeVersion(LegacyESVersion.V_7_10_2);
         } else {
-            Version.writeVersion(version, out);
+            out.writeVersion(version);
         }
         clusterName.writeTo(out);
         out.writeString(clusterUuid);
-        Build.writeBuild(build, out);
+        out.writeBuild(build);
         if (out.getVersion().before(LegacyESVersion.V_7_0_0)) {
             out.writeBoolean(true);
         }
diff --git a/server/src/main/java/org/opensearch/action/main/TransportMainAction.java b/server/src/main/java/org/opensearch/action/main/TransportMainAction.java
index ef6ebb27c4505..7c92b9f41d5ab 100644
--- a/server/src/main/java/org/opensearch/action/main/TransportMainAction.java
+++ b/server/src/main/java/org/opensearch/action/main/TransportMainAction.java
@@ -35,7 +35,6 @@
 import org.opensearch.Build;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.cluster.ClusterState;
@@ -44,10 +43,16 @@
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.node.Node;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Performs the main action
+ *
+ * @opensearch.internal
+ */
 public class TransportMainAction extends HandledTransportAction<MainRequest, MainResponse> {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(TransportMainAction.class);
diff --git a/server/src/main/java/org/opensearch/action/main/package-info.java b/server/src/main/java/org/opensearch/action/main/package-info.java
new file mode 100644
index 0000000000000..dc08f0a7b6303
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/main/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Main Response transport handlers. */
+package org.opensearch.action.main;
diff --git a/server/src/main/java/org/opensearch/action/resync/ResyncReplicationRequest.java b/server/src/main/java/org/opensearch/action/resync/ResyncReplicationRequest.java
index 2ecbc49384fe5..6a4f2f0607144 100644
--- a/server/src/main/java/org/opensearch/action/resync/ResyncReplicationRequest.java
+++ b/server/src/main/java/org/opensearch/action/resync/ResyncReplicationRequest.java
@@ -32,9 +32,9 @@
 package org.opensearch.action.resync;
 
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 
 import java.io.IOException;
@@ -43,6 +43,8 @@
 
 /**
  * Represents a batch of operations sent from the primary to its replicas during the primary-replica resync.
+ *
+ *  @opensearch.internal
  */
 public final class ResyncReplicationRequest extends ReplicatedWriteRequest<ResyncReplicationRequest> {
 
diff --git a/server/src/main/java/org/opensearch/action/resync/ResyncReplicationResponse.java b/server/src/main/java/org/opensearch/action/resync/ResyncReplicationResponse.java
index 1e052c5d80e80..d1c7be3673645 100644
--- a/server/src/main/java/org/opensearch/action/resync/ResyncReplicationResponse.java
+++ b/server/src/main/java/org/opensearch/action/resync/ResyncReplicationResponse.java
@@ -33,10 +33,15 @@
 
 import org.opensearch.action.support.WriteResponse;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Transport response for resyncing replication
+ *
+ * @opensearch.internal
+ */
 public final class ResyncReplicationResponse extends ReplicationResponse implements WriteResponse {
 
     public ResyncReplicationResponse() {}
diff --git a/server/src/main/java/org/opensearch/action/resync/TransportResyncReplicationAction.java b/server/src/main/java/org/opensearch/action/resync/TransportResyncReplicationAction.java
index ea596b12f262f..032fe83e2220b 100644
--- a/server/src/main/java/org/opensearch/action/resync/TransportResyncReplicationAction.java
+++ b/server/src/main/java/org/opensearch/action/resync/TransportResyncReplicationAction.java
@@ -32,7 +32,6 @@
 package org.opensearch.action.resync;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ReplicationOperation;
 import org.opensearch.action.support.replication.ReplicationResponse;
@@ -43,8 +42,9 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.SequenceNumbers;
@@ -64,6 +64,11 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+/**
+ * Perform replication resync
+ *
+ * @opensearch.internal
+ */
 public class TransportResyncReplicationAction extends TransportWriteAction<
     ResyncReplicationRequest,
     ResyncReplicationRequest,
@@ -253,6 +258,8 @@ public void handleException(TransportException exp) {
      * A proxy for primary-replica resync operations which are performed on replicas when a new primary is promoted.
      * Replica shards fail to execute resync operations will be failed but won't be marked as stale.
      * This avoids marking shards as stale during cluster restart but enforces primary-replica resync mandatory.
+     *
+     * @opensearch.internal
      */
     class ResyncActionReplicasProxy extends ReplicasProxy {
 
diff --git a/server/src/main/java/org/opensearch/action/resync/package-info.java b/server/src/main/java/org/opensearch/action/resync/package-info.java
new file mode 100644
index 0000000000000..61c46d85aecda
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/resync/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Resync action transport handlers. */
+package org.opensearch.action.resync;
diff --git a/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
index 190904145b091..1c0a1280ad550 100644
--- a/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
@@ -34,28 +34,30 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.NoShardAvailableActionException;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.routing.FailAwareWeightedRouting;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.internal.ShardSearchRequest;
+import org.opensearch.search.pipeline.PipelinedRequest;
 import org.opensearch.transport.Transport;
 
 import java.util.ArrayDeque;
@@ -63,6 +65,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
@@ -78,6 +81,8 @@
  * referred to as the {@code shardIndex}.
  * The fan out and collect algorithm is traditionally used as the initial phase which can either be a query execution or collection of
  * distributed frequencies
+ *
+ * @opensearch.internal
  */
 abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> extends SearchPhase implements SearchPhaseContext {
     private static final float DEFAULT_INDEX_BOOST = 1.0f;
@@ -103,7 +108,6 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
     private final AtomicInteger skippedOps = new AtomicInteger();
     private final TransportSearchAction.SearchTimeProvider timeProvider;
     private final SearchResponse.Clusters clusters;
-
     protected final GroupShardsIterator<SearchShardIterator> toSkipShardsIts;
     protected final GroupShardsIterator<SearchShardIterator> shardsIts;
     private final int expectedTotalOps;
@@ -112,8 +116,12 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
     private final Map<String, PendingExecutions> pendingExecutionsPerNode = new ConcurrentHashMap<>();
     private final boolean throttleConcurrentRequests;
 
+    private SearchPhase currentPhase;
+
     private final List<Releasable> releasables = new ArrayList<>();
 
+    private Optional<SearchRequestOperationsListener> searchRequestOperationsListener;
+
     AbstractSearchAsyncAction(
         String name,
         Logger logger,
@@ -131,7 +139,8 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
         SearchTask task,
         SearchPhaseResults<Result> resultConsumer,
         int maxConcurrentRequestsPerNode,
-        SearchResponse.Clusters clusters
+        SearchResponse.Clusters clusters,
+        SearchRequestOperationsListener searchRequestOperationsListener
     ) {
         super(name);
         final List<SearchShardIterator> toSkipIterators = new ArrayList<>();
@@ -167,6 +176,7 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
         this.indexRoutings = indexRoutings;
         this.results = resultConsumer;
         this.clusters = clusters;
+        this.searchRequestOperationsListener = Optional.ofNullable(searchRequestOperationsListener);
     }
 
     @Override
@@ -300,7 +310,16 @@ public void onFailure(Exception t) {
                          * It is possible to run into connection exceptions here because we are getting the connection early and might
                          * run into nodes that are not connected. In this case, on shard failure will move us to the next shard copy.
                          */
-                        fork(() -> onShardFailure(shardIndex, shard, shardIt, e));
+                        fork(() -> {
+                            // It only happens when onPhaseDone() is called and executePhaseOnShard() fails hard with an exception.
+                            // In this case calling onShardFailure() would overflow the operations counter, so the best we could do
+                            // here is to fail the phase and move on to the next one.
+                            if (totalOps.get() == expectedTotalOps) {
+                                onPhaseFailure(this, "The phase has failed", e);
+                            } else {
+                                onShardFailure(shardIndex, shard, shardIt, e);
+                            }
+                        });
                     } finally {
                         executeNext(pendingExecutions, thread);
                     }
@@ -358,6 +377,7 @@ public final void executeNextPhase(SearchPhase currentPhase, SearchPhase nextPha
                 : OpenSearchException.guessRootCauses(shardSearchFailures[0].getCause())[0];
             logger.debug(() -> new ParameterizedMessage("All shards failed for phase: [{}]", getName()), cause);
             onPhaseFailure(currentPhase, "all shards failed", cause);
+
         } else {
             Boolean allowPartialResults = request.allowPartialSearchResults();
             assert allowPartialResults != null : "SearchRequest missing setting for allowPartialSearchResults";
@@ -406,13 +426,24 @@ public final void executeNextPhase(SearchPhase currentPhase, SearchPhase nextPha
                     clusterState.version()
                 );
             }
+            onPhaseEnd();
             executePhase(nextPhase);
         }
     }
 
+    private void onPhaseEnd() {
+        this.searchRequestOperationsListener.ifPresent(searchRequestOperations -> { searchRequestOperations.onPhaseEnd(this); });
+    }
+
+    private void onPhaseStart(SearchPhase phase) {
+        setCurrentPhase(phase);
+        this.searchRequestOperationsListener.ifPresent(searchRequestOperations -> { searchRequestOperations.onPhaseStart(this); });
+    }
+
     private void executePhase(SearchPhase phase) {
         try {
-            phase.run();
+            onPhaseStart(phase);
+            phase.recordAndRun();
         } catch (Exception e) {
             if (logger.isDebugEnabled()) {
                 logger.debug(new ParameterizedMessage("Failed to execute [{}] while moving to [{}] phase", request, phase.getName()), e);
@@ -438,23 +469,41 @@ private void onShardFailure(final int shardIndex, @Nullable SearchShardTarget sh
         // we always add the shard failure for a specific shard instance
         // we do make sure to clean it on a successful response from a shard
         onShardFailure(shardIndex, shard, e);
-        final SearchShardTarget nextShard = shardIt.nextOrNull();
+        SearchShardTarget nextShard = FailAwareWeightedRouting.getInstance()
+            .findNext(shardIt, clusterState, e, () -> totalOps.incrementAndGet());
+
         final boolean lastShard = nextShard == null;
-        logger.debug(
-            () -> new ParameterizedMessage(
-                "{}: Failed to execute [{}] lastShard [{}]",
-                shard != null ? shard : shardIt.shardId(),
-                request,
-                lastShard
-            ),
-            e
-        );
+        if (logger.isTraceEnabled()) {
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "{}: Failed to execute [{}] lastShard [{}]",
+                    shard != null ? shard : shardIt.shardId(),
+                    request,
+                    lastShard
+                ),
+                e
+            );
+        } else {
+            // Log the message without an exception.
+            logger.debug(
+                new ParameterizedMessage(
+                    "{}: Failed to execute [{}] lastShard [{}]",
+                    shard != null ? shard : shardIt.shardId(),
+                    request,
+                    lastShard
+                )
+            );
+        }
         if (lastShard) {
             onShardGroupFailure(shardIndex, shard, e);
         }
         final int totalOps = this.totalOps.incrementAndGet();
         if (totalOps == expectedTotalOps) {
-            onPhaseDone();
+            try {
+                onPhaseDone();
+            } catch (final Exception ex) {
+                onPhaseFailure(this, "The phase has failed", ex);
+            }
         } else if (totalOps > expectedTotalOps) {
             throw new AssertionError(
                 "unexpected higher total ops [" + totalOps + "] compared to expected [" + expectedTotalOps + "]",
@@ -559,7 +608,11 @@ private void successfulShardExecution(SearchShardIterator shardsIt) {
         }
         final int xTotalOps = totalOps.addAndGet(remainingOpsOnIterator);
         if (xTotalOps == expectedTotalOps) {
-            onPhaseDone();
+            try {
+                onPhaseDone();
+            } catch (final Exception ex) {
+                onPhaseFailure(this, "The phase has failed", ex);
+            }
         } else if (xTotalOps > expectedTotalOps) {
             throw new AssertionError(
                 "unexpected higher total ops [" + xTotalOps + "] compared to expected [" + expectedTotalOps + "]",
@@ -568,6 +621,14 @@ private void successfulShardExecution(SearchShardIterator shardsIt) {
         }
     }
 
+    public SearchPhase getCurrentPhase() {
+        return currentPhase;
+    }
+
+    private void setCurrentPhase(SearchPhase phase) {
+        currentPhase = phase;
+    }
+
     @Override
     public final int getNumShards() {
         return results.getNumShards();
@@ -635,10 +696,13 @@ public void sendSearchResponse(InternalSearchResponse internalSearchResponse, At
             }
             listener.onResponse(buildSearchResponse(internalSearchResponse, failures, scrollId, searchContextId));
         }
+        onPhaseEnd();
+        setCurrentPhase(null);
     }
 
     @Override
     public final void onPhaseFailure(SearchPhase phase, String msg, Throwable cause) {
+        this.searchRequestOperationsListener.ifPresent(searchRequestOperations -> searchRequestOperations.onPhaseFailure(this));
         raisePhaseFailure(new SearchPhaseExecutionException(phase.getName(), msg, cause, buildShardFailures()));
     }
 
@@ -674,7 +738,11 @@ private void raisePhaseFailure(SearchPhaseExecutionException exception) {
      * @see #onShardResult(SearchPhaseResult, SearchShardIterator)
      */
     final void onPhaseDone() {  // as a tribute to @kimchy aka. finishHim()
-        executeNextPhase(this, getNextPhase(results, this));
+        final SearchPhase nextPhase = getNextPhase(results, this);
+        if (request instanceof PipelinedRequest && nextPhase != null) {
+            ((PipelinedRequest) request).transformSearchPhaseResults(results, this, this.getName(), nextPhase.getName());
+        }
+        executeNextPhase(this, nextPhase);
     }
 
     @Override
@@ -749,6 +817,11 @@ void executeNext(Runnable runnable, Thread originalThread) {
         }
     }
 
+    /**
+     * Pending Executions
+     *
+     * @opensearch.internal
+     */
     private static final class PendingExecutions {
         private final int permits;
         private int permitsTaken = 0;
diff --git a/server/src/main/java/org/opensearch/action/search/ArraySearchPhaseResults.java b/server/src/main/java/org/opensearch/action/search/ArraySearchPhaseResults.java
index 58cffe2ed5b8c..653b0e8aedb9d 100644
--- a/server/src/main/java/org/opensearch/action/search/ArraySearchPhaseResults.java
+++ b/server/src/main/java/org/opensearch/action/search/ArraySearchPhaseResults.java
@@ -39,6 +39,8 @@
 
 /**
  * This class acts as a basic result collection that can be extended to do on-the-fly reduction or result processing
+ *
+ * @opensearch.internal
  */
 class ArraySearchPhaseResults<Result extends SearchPhaseResult> extends SearchPhaseResults<Result> {
     final AtomicArray<Result> results;
@@ -64,7 +66,7 @@ boolean hasResult(int shardIndex) {
     }
 
     @Override
-    AtomicArray<Result> getAtomicArray() {
+    public AtomicArray<Result> getAtomicArray() {
         return results;
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/search/BottomSortValuesCollector.java b/server/src/main/java/org/opensearch/action/search/BottomSortValuesCollector.java
index 64f50d2f37cdb..c831c80b6455c 100644
--- a/server/src/main/java/org/opensearch/action/search/BottomSortValuesCollector.java
+++ b/server/src/main/java/org/opensearch/action/search/BottomSortValuesCollector.java
@@ -41,6 +41,8 @@
 
 /**
  * Utility class to keep track of the bottom doc's sort values in a distributed search.
+ *
+ * @opensearch.internal
  */
 class BottomSortValuesCollector {
     private final int topNSize;
diff --git a/server/src/main/java/org/opensearch/action/search/CanMatchPreFilterSearchPhase.java b/server/src/main/java/org/opensearch/action/search/CanMatchPreFilterSearchPhase.java
index 2e67e6aa93a72..ae481736ad0aa 100644
--- a/server/src/main/java/org/opensearch/action/search/CanMatchPreFilterSearchPhase.java
+++ b/server/src/main/java/org/opensearch/action/search/CanMatchPreFilterSearchPhase.java
@@ -33,10 +33,10 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.FixedBitSet;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchService.CanMatchResponse;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.builder.SearchSourceBuilder;
@@ -67,6 +67,8 @@
  * When the query primary sort is perform on a field, this phase extracts the min/max value in each shard and
  * sort them according to the provided order. This can be useful for instance to ensure that shards that contain recent
  * data are executed first when sorting by descending timestamp.
+ *
+ * @opensearch.internal
  */
 final class CanMatchPreFilterSearchPhase extends AbstractSearchAsyncAction<CanMatchResponse> {
 
@@ -88,11 +90,12 @@ final class CanMatchPreFilterSearchPhase extends AbstractSearchAsyncAction<CanMa
         ClusterState clusterState,
         SearchTask task,
         Function<GroupShardsIterator<SearchShardIterator>, SearchPhase> phaseFactory,
-        SearchResponse.Clusters clusters
+        SearchResponse.Clusters clusters,
+        SearchRequestOperationsListener searchRequestOperationsListener
     ) {
         // We set max concurrent shard requests to the number of shards so no throttling happens for can_match requests
         super(
-            "can_match",
+            SearchPhaseName.CAN_MATCH.getName(),
             logger,
             searchTransportService,
             nodeIdToConnection,
@@ -108,7 +111,8 @@ final class CanMatchPreFilterSearchPhase extends AbstractSearchAsyncAction<CanMa
             task,
             new CanMatchSearchPhaseResults(shardsIts.size()),
             shardsIts.size(),
-            clusters
+            clusters,
+            searchRequestOperationsListener
         );
         this.phaseFactory = phaseFactory;
         this.shardsIts = shardsIts;
@@ -202,6 +206,11 @@ private static Comparator<Integer> shardComparator(
         return comparator.thenComparing(index -> shardsIts.get(index).shardId());
     }
 
+    /**
+     * Inner class for determining if canMatch search phase results
+     *
+     * @opensearch.internal
+     */
     private static final class CanMatchSearchPhaseResults extends SearchPhaseResults<CanMatchResponse> {
         private final FixedBitSet possibleMatches;
         private final MinAndMax<?>[] minAndMaxes;
diff --git a/server/src/main/java/org/opensearch/action/search/ClearScrollAction.java b/server/src/main/java/org/opensearch/action/search/ClearScrollAction.java
index 91ae4b2109ae1..70072e5ec9156 100644
--- a/server/src/main/java/org/opensearch/action/search/ClearScrollAction.java
+++ b/server/src/main/java/org/opensearch/action/search/ClearScrollAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport Action for clearing a scroll
+ *
+ * @opensearch.internal
+ */
 public class ClearScrollAction extends ActionType<ClearScrollResponse> {
 
     public static final ClearScrollAction INSTANCE = new ClearScrollAction();
diff --git a/server/src/main/java/org/opensearch/action/search/ClearScrollController.java b/server/src/main/java/org/opensearch/action/search/ClearScrollController.java
index 390f5e2b99e63..2ce94bfd682fe 100644
--- a/server/src/main/java/org/opensearch/action/search/ClearScrollController.java
+++ b/server/src/main/java/org/opensearch/action/search/ClearScrollController.java
@@ -33,15 +33,15 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.transport.Transport;
-import org.opensearch.transport.TransportResponse;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -53,6 +53,11 @@
 import java.util.function.BiFunction;
 import java.util.stream.Collectors;
 
+/**
+ * Main controller for clearing a scroll
+ *
+ * @opensearch.internal
+ */
 public final class ClearScrollController implements Runnable {
     private final DiscoveryNodes nodes;
     private final SearchTransportService searchTransportService;
diff --git a/server/src/main/java/org/opensearch/action/search/ClearScrollRequest.java b/server/src/main/java/org/opensearch/action/search/ClearScrollRequest.java
index 3fb1ebcd6fcc2..f71ddcf1691f8 100644
--- a/server/src/main/java/org/opensearch/action/search/ClearScrollRequest.java
+++ b/server/src/main/java/org/opensearch/action/search/ClearScrollRequest.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,6 +47,11 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport request for clearing a search scroll
+ *
+ * @opensearch.internal
+ */
 public class ClearScrollRequest extends ActionRequest implements ToXContentObject {
 
     private List<String> scrollIds;
diff --git a/server/src/main/java/org/opensearch/action/search/ClearScrollRequestBuilder.java b/server/src/main/java/org/opensearch/action/search/ClearScrollRequestBuilder.java
index ba76b641c8f56..63f64e02a9dd2 100644
--- a/server/src/main/java/org/opensearch/action/search/ClearScrollRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/search/ClearScrollRequestBuilder.java
@@ -37,6 +37,11 @@
 
 import java.util.List;
 
+/**
+ * Transport request builder for clearing a search scroll
+ *
+ * @opensearch.internal
+ */
 public class ClearScrollRequestBuilder extends ActionRequestBuilder<ClearScrollRequest, ClearScrollResponse> {
 
     public ClearScrollRequestBuilder(OpenSearchClient client, ClearScrollAction action) {
diff --git a/server/src/main/java/org/opensearch/action/search/ClearScrollResponse.java b/server/src/main/java/org/opensearch/action/search/ClearScrollResponse.java
index 7a989e646e4d0..4428f693763ed 100644
--- a/server/src/main/java/org/opensearch/action/search/ClearScrollResponse.java
+++ b/server/src/main/java/org/opensearch/action/search/ClearScrollResponse.java
@@ -32,23 +32,28 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Transport response for clearing a search scroll
+ *
+ * @opensearch.internal
+ */
 public class ClearScrollResponse extends ActionResponse implements StatusToXContentObject {
 
     private static final ParseField SUCCEEDED = new ParseField("succeeded");
diff --git a/server/src/main/java/org/opensearch/action/search/CountedCollector.java b/server/src/main/java/org/opensearch/action/search/CountedCollector.java
index cb00902b52b7c..c73c4be2fa662 100644
--- a/server/src/main/java/org/opensearch/action/search/CountedCollector.java
+++ b/server/src/main/java/org/opensearch/action/search/CountedCollector.java
@@ -40,6 +40,8 @@
  * This is a simple base class to simplify fan out to shards and collect their results. Each results passed to
  * {@link #onResult(SearchPhaseResult)} will be set to the provided result array
  * where the given index is used to set the result on the array.
+ *
+ * @opensearch.internal
  */
 final class CountedCollector<R extends SearchPhaseResult> {
     private final ArraySearchPhaseResults<R> resultConsumer;
diff --git a/server/src/main/java/org/opensearch/action/search/CreatePitAction.java b/server/src/main/java/org/opensearch/action/search/CreatePitAction.java
new file mode 100644
index 0000000000000..7ffa30a182458
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/CreatePitAction.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action type for creating PIT reader context
+ */
+public class CreatePitAction extends ActionType<CreatePitResponse> {
+    public static final CreatePitAction INSTANCE = new CreatePitAction();
+    public static final String NAME = "indices:data/read/point_in_time/create";
+
+    private CreatePitAction() {
+        super(NAME, CreatePitResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/CreatePitController.java b/server/src/main/java/org/opensearch/action/search/CreatePitController.java
new file mode 100644
index 0000000000000..1d11ad2760675
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/CreatePitController.java
@@ -0,0 +1,329 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.StepListener;
+import org.opensearch.action.support.GroupedActionListener;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.SearchShardTarget;
+import org.opensearch.tasks.Task;
+import org.opensearch.transport.Transport;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.BiFunction;
+import java.util.stream.Collectors;
+
+import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
+
+/**
+ * Controller for creating PIT reader context
+ * Phase 1 of create PIT request : Create PIT reader contexts in the associated shards with a temporary keep alive
+ * Phase 2 of create PIT : Update PIT reader context with PIT ID and keep alive from request and
+ * fail user request if any of the updates in this phase are failed - we clean up PITs in case of such failures.
+ * This two phase approach is used to save PIT ID as part of context which is later used for other use cases like list PIT etc.
+ */
+public class CreatePitController {
+    private final SearchTransportService searchTransportService;
+    private final ClusterService clusterService;
+    private final TransportSearchAction transportSearchAction;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final PitService pitService;
+    private static final Logger logger = LogManager.getLogger(CreatePitController.class);
+    public static final Setting<TimeValue> PIT_INIT_KEEP_ALIVE = Setting.positiveTimeSetting(
+        "point_in_time.init.keep_alive",
+        timeValueSeconds(30),
+        Setting.Property.NodeScope
+    );
+
+    @Inject
+    public CreatePitController(
+        SearchTransportService searchTransportService,
+        ClusterService clusterService,
+        TransportSearchAction transportSearchAction,
+        NamedWriteableRegistry namedWriteableRegistry,
+        PitService pitService
+    ) {
+        this.searchTransportService = searchTransportService;
+        this.clusterService = clusterService;
+        this.transportSearchAction = transportSearchAction;
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        this.pitService = pitService;
+    }
+
+    /**
+     * This method creates PIT reader context
+     */
+    public void executeCreatePit(
+        CreatePitRequest request,
+        Task task,
+        StepListener<SearchResponse> createPitListener,
+        ActionListener<CreatePitResponse> updatePitIdListener
+    ) {
+        SearchRequest searchRequest = new SearchRequest(request.getIndices());
+        searchRequest.preference(request.getPreference());
+        searchRequest.routing(request.getRouting());
+        searchRequest.indicesOptions(request.getIndicesOptions());
+        searchRequest.allowPartialSearchResults(request.shouldAllowPartialPitCreation());
+        SearchTask searchTask = searchRequest.createTask(
+            task.getId(),
+            task.getType(),
+            task.getAction(),
+            task.getParentTaskId(),
+            Collections.emptyMap()
+        );
+        /**
+         * This is needed for cross cluster functionality to work with PITs and current ccsMinimizeRoundTrips is
+         * not supported for point in time
+         */
+        searchRequest.setCcsMinimizeRoundtrips(false);
+        /**
+         * Phase 1 of create PIT
+         */
+        executeCreatePit(searchTask, searchRequest, createPitListener);
+
+        /**
+         * Phase 2 of create PIT where we update pit id in pit contexts
+         */
+        createPitListener.whenComplete(
+            searchResponse -> { executeUpdatePitId(request, searchRequest, searchResponse, updatePitIdListener); },
+            updatePitIdListener::onFailure
+        );
+    }
+
+    /**
+     * Creates PIT reader context with temporary keep alive
+     */
+    void executeCreatePit(Task task, SearchRequest searchRequest, StepListener<SearchResponse> createPitListener) {
+        logger.debug(
+            () -> new ParameterizedMessage("Executing creation of PIT context for indices [{}]", Arrays.toString(searchRequest.indices()))
+        );
+        transportSearchAction.executeRequest(
+            task,
+            searchRequest,
+            TransportCreatePitAction.CREATE_PIT_ACTION,
+            true,
+            new TransportSearchAction.SinglePhaseSearchAction() {
+                @Override
+                public void executeOnShardTarget(
+                    SearchTask searchTask,
+                    SearchShardTarget target,
+                    Transport.Connection connection,
+                    ActionListener<SearchPhaseResult> searchPhaseResultActionListener
+                ) {
+                    searchTransportService.createPitContext(
+                        connection,
+                        new TransportCreatePitAction.CreateReaderContextRequest(
+                            target.getShardId(),
+                            PIT_INIT_KEEP_ALIVE.get(clusterService.getSettings())
+                        ),
+                        searchTask,
+                        ActionListener.wrap(r -> searchPhaseResultActionListener.onResponse(r), searchPhaseResultActionListener::onFailure)
+                    );
+                }
+            },
+            createPitListener
+        );
+    }
+
+    /**
+     * Updates PIT ID, keep alive and createdTime of PIT reader context
+     */
+    void executeUpdatePitId(
+        CreatePitRequest request,
+        SearchRequest searchRequest,
+        SearchResponse searchResponse,
+        ActionListener<CreatePitResponse> updatePitIdListener
+    ) {
+        logger.debug(
+            () -> new ParameterizedMessage(
+                "Updating PIT context with PIT ID [{}], creation time and keep alive",
+                searchResponse.pointInTimeId()
+            )
+        );
+        /**
+         * store the create time ( same create time for all PIT contexts across shards ) to be used
+         * for list PIT api
+         */
+        final long relativeStartNanos = System.nanoTime();
+        final TransportSearchAction.SearchTimeProvider timeProvider = new TransportSearchAction.SearchTimeProvider(
+            searchRequest.getOrCreateAbsoluteStartMillis(),
+            relativeStartNanos,
+            System::nanoTime
+        );
+        final long creationTime = timeProvider.getAbsoluteStartMillis();
+        CreatePitResponse createPITResponse = new CreatePitResponse(
+            searchResponse.pointInTimeId(),
+            creationTime,
+            searchResponse.getTotalShards(),
+            searchResponse.getSuccessfulShards(),
+            searchResponse.getSkippedShards(),
+            searchResponse.getFailedShards(),
+            searchResponse.getShardFailures()
+        );
+        SearchContextId contextId = SearchContextId.decode(namedWriteableRegistry, createPITResponse.getId());
+        final StepListener<BiFunction<String, String, DiscoveryNode>> lookupListener = getConnectionLookupListener(contextId);
+        lookupListener.whenComplete(nodelookup -> {
+            final ActionListener<UpdatePitContextResponse> groupedActionListener = getGroupedListener(
+                updatePitIdListener,
+                createPITResponse,
+                contextId.shards().size(),
+                contextId.shards().values()
+            );
+            for (Map.Entry<ShardId, SearchContextIdForNode> entry : contextId.shards().entrySet()) {
+                DiscoveryNode node = nodelookup.apply(entry.getValue().getClusterAlias(), entry.getValue().getNode());
+                if (node == null) {
+                    node = this.clusterService.state().getNodes().get(entry.getValue().getNode());
+                }
+                if (node == null) {
+                    logger.error(
+                        () -> new ParameterizedMessage(
+                            "Create pit update phase for PIT ID [{}] failed " + "because node [{}] not found",
+                            searchResponse.pointInTimeId(),
+                            entry.getValue().getNode()
+                        )
+                    );
+                    groupedActionListener.onFailure(
+                        new OpenSearchException(
+                            "Create pit update phase for PIT ID ["
+                                + searchResponse.pointInTimeId()
+                                + "] failed because node["
+                                + entry.getValue().getNode()
+                                + "] "
+                                + "not found"
+                        )
+                    );
+                    return;
+                }
+                try {
+                    final Transport.Connection connection = searchTransportService.getConnection(entry.getValue().getClusterAlias(), node);
+                    searchTransportService.updatePitContext(
+                        connection,
+                        new UpdatePitContextRequest(
+                            entry.getValue().getSearchContextId(),
+                            createPITResponse.getId(),
+                            request.getKeepAlive().millis(),
+                            creationTime
+                        ),
+                        groupedActionListener
+                    );
+                } catch (Exception e) {
+                    String nodeName = node.getName();
+                    logger.error(
+                        () -> new ParameterizedMessage(
+                            "Create pit update phase failed for PIT ID [{}] on node [{}]",
+                            searchResponse.pointInTimeId(),
+                            nodeName
+                        ),
+                        e
+                    );
+                    groupedActionListener.onFailure(
+                        new OpenSearchException(
+                            "Create pit update phase for PIT ID [" + searchResponse.pointInTimeId() + "] failed on node[" + node + "]",
+                            e
+                        )
+                    );
+                }
+            }
+        }, updatePitIdListener::onFailure);
+    }
+
+    private StepListener<BiFunction<String, String, DiscoveryNode>> getConnectionLookupListener(SearchContextId contextId) {
+        ClusterState state = clusterService.state();
+        final Set<String> clusters = contextId.shards()
+            .values()
+            .stream()
+            .filter(ctx -> Strings.isEmpty(ctx.getClusterAlias()) == false)
+            .map(SearchContextIdForNode::getClusterAlias)
+            .collect(Collectors.toSet());
+        return (StepListener<BiFunction<String, String, DiscoveryNode>>) SearchUtils.getConnectionLookupListener(
+            searchTransportService.getRemoteClusterService(),
+            state,
+            clusters
+        );
+    }
+
+    private ActionListener<UpdatePitContextResponse> getGroupedListener(
+        ActionListener<CreatePitResponse> updatePitIdListener,
+        CreatePitResponse createPITResponse,
+        int size,
+        Collection<SearchContextIdForNode> contexts
+    ) {
+        return new GroupedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(final Collection<UpdatePitContextResponse> responses) {
+                updatePitIdListener.onResponse(createPITResponse);
+            }
+
+            @Override
+            public void onFailure(final Exception e) {
+                cleanupContexts(contexts, createPITResponse.getId());
+                updatePitIdListener.onFailure(e);
+            }
+        }, size);
+    }
+
+    /**
+     * Cleanup all created PIT contexts in case of failure
+     */
+    private void cleanupContexts(Collection<SearchContextIdForNode> contexts, String pitId) {
+        ActionListener<DeletePitResponse> deleteListener = new ActionListener<>() {
+            @Override
+            public void onResponse(DeletePitResponse response) {
+                // this is invoke and forget call
+                final StringBuilder failedPitsStringBuilder = new StringBuilder();
+                response.getDeletePitResults()
+                    .stream()
+                    .filter(r -> !r.isSuccessful())
+                    .forEach(r -> failedPitsStringBuilder.append(r.getPitId()).append(","));
+                logger.warn(() -> new ParameterizedMessage("Failed to delete PIT IDs {}", failedPitsStringBuilder.toString()));
+                if (logger.isDebugEnabled()) {
+                    final StringBuilder successfulPitsStringBuilder = new StringBuilder();
+                    response.getDeletePitResults()
+                        .stream()
+                        .filter(r -> r.isSuccessful())
+                        .forEach(r -> successfulPitsStringBuilder.append(r.getPitId()).append(","));
+                    logger.debug(() -> new ParameterizedMessage("Deleted PIT with IDs {}", successfulPitsStringBuilder.toString()));
+                }
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Cleaning up PIT contexts failed ", e);
+            }
+        };
+        Map<String, List<PitSearchContextIdForNode>> nodeToContextsMap = new HashMap<>();
+        for (SearchContextIdForNode context : contexts) {
+            List<PitSearchContextIdForNode> contextIdsForNode = nodeToContextsMap.getOrDefault(context.getNode(), new ArrayList<>());
+            contextIdsForNode.add(new PitSearchContextIdForNode(pitId, context));
+            nodeToContextsMap.put(context.getNode(), contextIdsForNode);
+        }
+        pitService.deletePitContexts(nodeToContextsMap, deleteListener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/CreatePitRequest.java b/server/src/main/java/org/opensearch/action/search/CreatePitRequest.java
new file mode 100644
index 0000000000000..a47127f18e18d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/CreatePitRequest.java
@@ -0,0 +1,195 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.IndicesRequest;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.tasks.Task;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * A request to make create point in time against one or more indices.
+ */
+public class CreatePitRequest extends ActionRequest implements IndicesRequest.Replaceable, ToXContent {
+
+    // keep alive for pit reader context
+    private TimeValue keepAlive;
+
+    // this describes whether PIT can be created with partial failures
+    private Boolean allowPartialPitCreation;
+    @Nullable
+    private String routing = null;
+    @Nullable
+    private String preference = null;
+    private String[] indices = Strings.EMPTY_ARRAY;
+    private IndicesOptions indicesOptions = SearchRequest.DEFAULT_INDICES_OPTIONS;
+
+    public CreatePitRequest(TimeValue keepAlive, Boolean allowPartialPitCreation, String... indices) {
+        this.keepAlive = keepAlive;
+        this.allowPartialPitCreation = allowPartialPitCreation;
+        this.indices = indices;
+    }
+
+    public CreatePitRequest(StreamInput in) throws IOException {
+        super(in);
+        indices = in.readStringArray();
+        indicesOptions = IndicesOptions.readIndicesOptions(in);
+        routing = in.readOptionalString();
+        preference = in.readOptionalString();
+        keepAlive = in.readTimeValue();
+        allowPartialPitCreation = in.readOptionalBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(indices);
+        indicesOptions.writeIndicesOptions(out);
+        out.writeOptionalString(routing);
+        out.writeOptionalString(preference);
+        out.writeTimeValue(keepAlive);
+        out.writeOptionalBoolean(allowPartialPitCreation);
+    }
+
+    public String getRouting() {
+        return routing;
+    }
+
+    public String getPreference() {
+        return preference;
+    }
+
+    public String[] getIndices() {
+        return indices;
+    }
+
+    public IndicesOptions getIndicesOptions() {
+        return indicesOptions;
+    }
+
+    public TimeValue getKeepAlive() {
+        return keepAlive;
+    }
+
+    /**
+     * Sets if this request should allow partial results.
+     */
+    public void allowPartialPitCreation(Boolean allowPartialPitCreation) {
+        this.allowPartialPitCreation = allowPartialPitCreation;
+    }
+
+    public boolean shouldAllowPartialPitCreation() {
+        return allowPartialPitCreation;
+    }
+
+    public void setRouting(String routing) {
+        this.routing = routing;
+    }
+
+    public void setPreference(String preference) {
+        this.preference = preference;
+    }
+
+    public void setIndices(String[] indices) {
+        this.indices = indices;
+    }
+
+    public void setIndicesOptions(IndicesOptions indicesOptions) {
+        this.indicesOptions = Objects.requireNonNull(indicesOptions, "indicesOptions must not be null");
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (keepAlive == null) {
+            validationException = addValidationError("keep alive not specified", validationException);
+        }
+        return validationException;
+    }
+
+    @Override
+    public String[] indices() {
+        return indices;
+    }
+
+    @Override
+    public IndicesOptions indicesOptions() {
+        return indicesOptions;
+    }
+
+    public CreatePitRequest indicesOptions(IndicesOptions indicesOptions) {
+        this.indicesOptions = Objects.requireNonNull(indicesOptions, "indicesOptions must not be null");
+        return this;
+    }
+
+    public void setKeepAlive(TimeValue keepAlive) {
+        this.keepAlive = keepAlive;
+    }
+
+    public final String buildDescription() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("indices[");
+        Strings.arrayToDelimitedString(indices, ",", sb);
+        sb.append("], ");
+        sb.append("pointintime[").append(keepAlive).append("], ");
+        sb.append("allowPartialPitCreation[").append(allowPartialPitCreation).append("], ");
+        return sb.toString();
+    }
+
+    @Override
+    public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+        return new Task(id, type, action, this.buildDescription(), parentTaskId, headers);
+    }
+
+    private void validateIndices(String... indices) {
+        Objects.requireNonNull(indices, "indices must not be null");
+        for (String index : indices) {
+            Objects.requireNonNull(index, "index must not be null");
+        }
+    }
+
+    @Override
+    public CreatePitRequest indices(String... indices) {
+        validateIndices(indices);
+        this.indices = indices;
+        return this;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field("keep_alive", keepAlive);
+        builder.field("allow_partial_pit_creation", allowPartialPitCreation);
+        if (indices != null) {
+            builder.startArray("indices");
+            for (String index : indices) {
+                builder.value(index);
+            }
+            builder.endArray();
+        }
+        if (indicesOptions != null) {
+            indicesOptions.toXContent(builder, params);
+        }
+        return builder;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/CreatePitResponse.java b/server/src/main/java/org/opensearch/action/search/CreatePitResponse.java
new file mode 100644
index 0000000000000..aa841a02f1d20
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/CreatePitResponse.java
@@ -0,0 +1,232 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.common.xcontent.StatusToXContentObject;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.rest.action.RestActions;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * Create point in time response with point in time id and shard success / failures
+ */
+public class CreatePitResponse extends ActionResponse implements StatusToXContentObject {
+    private static final ParseField ID = new ParseField("pit_id");
+    private static final ParseField CREATION_TIME = new ParseField("creation_time");
+
+    // point in time id
+    private final String id;
+    private final int totalShards;
+    private final int successfulShards;
+    private final int failedShards;
+    private final int skippedShards;
+    private final ShardSearchFailure[] shardFailures;
+    private final long creationTime;
+
+    public CreatePitResponse(StreamInput in) throws IOException {
+        super(in);
+        id = in.readString();
+        totalShards = in.readVInt();
+        successfulShards = in.readVInt();
+        failedShards = in.readVInt();
+        skippedShards = in.readVInt();
+        creationTime = in.readLong();
+        int size = in.readVInt();
+        if (size == 0) {
+            shardFailures = ShardSearchFailure.EMPTY_ARRAY;
+        } else {
+            shardFailures = new ShardSearchFailure[size];
+            for (int i = 0; i < shardFailures.length; i++) {
+                shardFailures[i] = ShardSearchFailure.readShardSearchFailure(in);
+            }
+        }
+    }
+
+    public CreatePitResponse(
+        String id,
+        long creationTime,
+        int totalShards,
+        int successfulShards,
+        int skippedShards,
+        int failedShards,
+        ShardSearchFailure[] shardFailures
+    ) {
+        this.id = id;
+        this.creationTime = creationTime;
+        this.totalShards = totalShards;
+        this.successfulShards = successfulShards;
+        this.skippedShards = skippedShards;
+        this.failedShards = failedShards;
+        this.shardFailures = shardFailures;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field(ID.getPreferredName(), id);
+        RestActions.buildBroadcastShardsHeader(
+            builder,
+            params,
+            getTotalShards(),
+            getSuccessfulShards(),
+            getSkippedShards(),
+            getFailedShards(),
+            getShardFailures()
+        );
+        builder.field(CREATION_TIME.getPreferredName(), creationTime);
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * Parse the create PIT response body into a new {@link CreatePitResponse} object
+     */
+    public static CreatePitResponse fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        parser.nextToken();
+        return innerFromXContent(parser);
+    }
+
+    public static CreatePitResponse innerFromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.FIELD_NAME, parser.currentToken(), parser);
+        String currentFieldName = parser.currentName();
+        int successfulShards = -1;
+        int totalShards = -1;
+        int skippedShards = 0;
+        int failedShards = 0;
+        String id = null;
+        long creationTime = 0;
+        List<ShardSearchFailure> failures = new ArrayList<>();
+        for (XContentParser.Token token = parser.nextToken(); token != XContentParser.Token.END_OBJECT; token = parser.nextToken()) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                currentFieldName = parser.currentName();
+            } else if (token.isValue()) {
+                if (CREATION_TIME.match(currentFieldName, parser.getDeprecationHandler())) {
+                    creationTime = parser.longValue();
+                } else if (ID.match(currentFieldName, parser.getDeprecationHandler())) {
+                    id = parser.text();
+                } else {
+                    parser.skipChildren();
+                }
+            } else if (token == XContentParser.Token.START_OBJECT) {
+                if (RestActions._SHARDS_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            currentFieldName = parser.currentName();
+                        } else if (token.isValue()) {
+                            if (RestActions.FAILED_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                                failedShards = parser.intValue(); // we don't need it but need to consume it
+                            } else if (RestActions.SUCCESSFUL_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                                successfulShards = parser.intValue();
+                            } else if (RestActions.TOTAL_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                                totalShards = parser.intValue();
+                            } else if (RestActions.SKIPPED_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                                skippedShards = parser.intValue();
+                            } else {
+                                parser.skipChildren();
+                            }
+                        } else if (token == XContentParser.Token.START_ARRAY) {
+                            if (RestActions.FAILURES_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                                while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                                    failures.add(ShardSearchFailure.fromXContent(parser));
+                                }
+                            } else {
+                                parser.skipChildren();
+                            }
+                        } else {
+                            parser.skipChildren();
+                        }
+                    }
+                } else {
+                    parser.skipChildren();
+                }
+            }
+        }
+
+        return new CreatePitResponse(
+            id,
+            creationTime,
+            totalShards,
+            successfulShards,
+            skippedShards,
+            failedShards,
+            failures.toArray(ShardSearchFailure.EMPTY_ARRAY)
+        );
+    }
+
+    public long getCreationTime() {
+        return creationTime;
+    }
+
+    /**
+     * The failed number of shards the search was executed on.
+     */
+    public int getFailedShards() {
+        return shardFailures.length;
+    }
+
+    /**
+     * The failures that occurred during the search.
+     */
+    public ShardSearchFailure[] getShardFailures() {
+        return this.shardFailures;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(id);
+        out.writeVInt(totalShards);
+        out.writeVInt(successfulShards);
+        out.writeVInt(failedShards);
+        out.writeVInt(skippedShards);
+        out.writeLong(creationTime);
+        out.writeVInt(shardFailures.length);
+        for (ShardSearchFailure shardSearchFailure : shardFailures) {
+            shardSearchFailure.writeTo(out);
+        }
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    /**
+     * The total number of shards the create pit operation was executed on.
+     */
+    public int getTotalShards() {
+        return totalShards;
+    }
+
+    /**
+     * The successful number of shards the create pit operation was executed on.
+     */
+    public int getSuccessfulShards() {
+        return successfulShards;
+    }
+
+    public int getSkippedShards() {
+        return skippedShards;
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.status(successfulShards, totalShards, shardFailures);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeletePitAction.java b/server/src/main/java/org/opensearch/action/search/DeletePitAction.java
new file mode 100644
index 0000000000000..aa305ecfe73ab
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeletePitAction.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action type for deleting point in time searches
+ */
+public class DeletePitAction extends ActionType<DeletePitResponse> {
+
+    public static final DeletePitAction INSTANCE = new DeletePitAction();
+    public static final String NAME = "indices:data/read/point_in_time/delete";
+
+    private DeletePitAction() {
+        super(NAME, DeletePitResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeletePitInfo.java b/server/src/main/java/org/opensearch/action/search/DeletePitInfo.java
new file mode 100644
index 0000000000000..40098c6670b65
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeletePitInfo.java
@@ -0,0 +1,83 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * This class captures if deletion of pit is successful along with pit id
+ */
+public class DeletePitInfo extends TransportResponse implements Writeable, ToXContent {
+    /**
+     * This will be true if PIT reader contexts are deleted ond also if contexts are not found.
+     */
+    private final boolean successful;
+
+    private final String pitId;
+
+    public DeletePitInfo(boolean successful, String pitId) {
+        this.successful = successful;
+        this.pitId = pitId;
+    }
+
+    public DeletePitInfo(StreamInput in) throws IOException {
+        successful = in.readBoolean();
+        pitId = in.readString();
+
+    }
+
+    public boolean isSuccessful() {
+        return successful;
+    }
+
+    public String getPitId() {
+        return pitId;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeBoolean(successful);
+        out.writeString(pitId);
+    }
+
+    static final ConstructingObjectParser<DeletePitInfo, Void> PARSER = new ConstructingObjectParser<>(
+        "delete_pit_info",
+        true,
+        args -> new DeletePitInfo((boolean) args[0], (String) args[1])
+    );
+
+    static {
+        PARSER.declareBoolean(constructorArg(), new ParseField("successful"));
+        PARSER.declareString(constructorArg(), new ParseField("pit_id"));
+    }
+
+    private static final ParseField SUCCESSFUL = new ParseField("successful");
+    private static final ParseField PIT_ID = new ParseField("pit_id");
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field(SUCCESSFUL.getPreferredName(), successful);
+        builder.field(PIT_ID.getPreferredName(), pitId);
+        builder.endObject();
+        return builder;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeletePitRequest.java b/server/src/main/java/org/opensearch/action/search/DeletePitRequest.java
new file mode 100644
index 0000000000000..62f67991083f2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeletePitRequest.java
@@ -0,0 +1,126 @@
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+
+/**
+ * Request to delete one or more PIT search contexts based on IDs.
+ */
+public class DeletePitRequest extends ActionRequest implements ToXContentObject {
+
+    /**
+     * List of PIT IDs to be deleted , and use "_all" to delete all PIT reader contexts
+     */
+    private final List<String> pitIds = new ArrayList<>();
+
+    public DeletePitRequest(StreamInput in) throws IOException {
+        super(in);
+        pitIds.addAll(Arrays.asList(in.readStringArray()));
+    }
+
+    public DeletePitRequest(String... pitIds) {
+        this.pitIds.addAll(Arrays.asList(pitIds));
+    }
+
+    public DeletePitRequest(List<String> pitIds) {
+        this.pitIds.addAll(pitIds);
+    }
+
+    public void clearAndSetPitIds(List<String> pitIds) {
+        this.pitIds.clear();
+        this.pitIds.addAll(pitIds);
+    }
+
+    public DeletePitRequest() {}
+
+    public List<String> getPitIds() {
+        return pitIds;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        ActionRequestValidationException validationException = null;
+        if (pitIds == null || pitIds.isEmpty()) {
+            validationException = addValidationError("no pit ids specified", validationException);
+        }
+        return validationException;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        if (pitIds == null) {
+            out.writeVInt(0);
+        } else {
+            out.writeStringArray(pitIds.toArray(new String[pitIds.size()]));
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject();
+        builder.startArray("pit_id");
+        for (String pitId : pitIds) {
+            builder.value(pitId);
+        }
+        builder.endArray();
+        builder.endObject();
+        return builder;
+    }
+
+    public void fromXContent(XContentParser parser) throws IOException {
+        pitIds.clear();
+        if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+            throw new IllegalArgumentException("Malformed content, must start with an object");
+        } else {
+            XContentParser.Token token;
+            String currentFieldName = null;
+            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    currentFieldName = parser.currentName();
+                } else if ("pit_id".equals(currentFieldName)) {
+                    if (token == XContentParser.Token.START_ARRAY) {
+                        while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                            if (token.isValue() == false) {
+                                throw new IllegalArgumentException("pit_id array element should only contain pit_id");
+                            }
+                            pitIds.add(parser.text());
+                        }
+                    } else {
+                        if (token.isValue() == false) {
+                            throw new IllegalArgumentException("pit_id element should only contain pit_id");
+                        }
+                        pitIds.add(parser.text());
+                    }
+                } else {
+                    throw new IllegalArgumentException(
+                        "Unknown parameter [" + currentFieldName + "] in request body or parameter is of the wrong type[" + token + "] "
+                    );
+                }
+            }
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeletePitResponse.java b/server/src/main/java/org/opensearch/action/search/DeletePitResponse.java
new file mode 100644
index 0000000000000..00274f0e610a9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeletePitResponse.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.common.xcontent.StatusToXContentObject;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.opensearch.core.rest.RestStatus.OK;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * Response class for delete pits flow which clears the point in time search contexts
+ */
+public class DeletePitResponse extends ActionResponse implements StatusToXContentObject {
+
+    private final List<DeletePitInfo> deletePitResults;
+
+    public DeletePitResponse(List<DeletePitInfo> deletePitResults) {
+        this.deletePitResults = deletePitResults;
+    }
+
+    public DeletePitResponse(StreamInput in) throws IOException {
+        super(in);
+        int size = in.readVInt();
+        deletePitResults = new ArrayList<>();
+        for (int i = 0; i < size; i++) {
+            deletePitResults.add(new DeletePitInfo(in));
+        }
+
+    }
+
+    public List<DeletePitInfo> getDeletePitResults() {
+        return deletePitResults;
+    }
+
+    /**
+     * @return Whether the attempt to delete PIT was successful.
+     */
+    @Override
+    public RestStatus status() {
+        return OK;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVInt(deletePitResults.size());
+        for (DeletePitInfo deletePitResult : deletePitResults) {
+            deletePitResult.writeTo(out);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject();
+        builder.startArray("pits");
+        for (DeletePitInfo response : deletePitResults) {
+            response.toXContent(builder, params);
+        }
+        builder.endArray();
+        builder.endObject();
+        return builder;
+    }
+
+    private static final ConstructingObjectParser<DeletePitResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "delete_pit_response",
+        true,
+        (Object[] parsedObjects) -> {
+            @SuppressWarnings("unchecked")
+            List<DeletePitInfo> deletePitInfoList = (List<DeletePitInfo>) parsedObjects[0];
+            return new DeletePitResponse(deletePitInfoList);
+        }
+    );
+    static {
+        PARSER.declareObjectArray(constructorArg(), DeletePitInfo.PARSER, new ParseField("pits"));
+    }
+
+    public static DeletePitResponse fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineAction.java b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineAction.java
new file mode 100644
index 0000000000000..65f8cf3de9506
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+
+/**
+ * Action type to delete a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class DeleteSearchPipelineAction extends ActionType<AcknowledgedResponse> {
+    public static final DeleteSearchPipelineAction INSTANCE = new DeleteSearchPipelineAction();
+    public static final String NAME = "cluster:admin/search/pipeline/delete";
+
+    public DeleteSearchPipelineAction() {
+        super(NAME, AcknowledgedResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineRequest.java b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineRequest.java
new file mode 100644
index 0000000000000..2c6ab6437fd2a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineRequest.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.master.AcknowledgedRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request to delete a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class DeleteSearchPipelineRequest extends AcknowledgedRequest<DeleteSearchPipelineRequest> {
+    private String id;
+
+    public DeleteSearchPipelineRequest(String id) {
+        this.id = Objects.requireNonNull(id);
+    }
+
+    public DeleteSearchPipelineRequest() {}
+
+    public DeleteSearchPipelineRequest(StreamInput in) throws IOException {
+        super(in);
+        id = in.readString();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(id);
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineTransportAction.java b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineTransportAction.java
new file mode 100644
index 0000000000000..ac83a6bb6b765
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/DeleteSearchPipelineTransportAction.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Perform the action of deleting a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class DeleteSearchPipelineTransportAction extends TransportClusterManagerNodeAction<
+    DeleteSearchPipelineRequest,
+    AcknowledgedResponse> {
+    private final SearchPipelineService searchPipelineService;
+
+    @Inject
+    public DeleteSearchPipelineTransportAction(
+        ThreadPool threadPool,
+        SearchPipelineService searchPipelineService,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            DeleteSearchPipelineAction.NAME,
+            transportService,
+            searchPipelineService.getClusterService(),
+            threadPool,
+            actionFilters,
+            DeleteSearchPipelineRequest::new,
+            indexNameExpressionResolver
+        );
+        this.searchPipelineService = searchPipelineService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected AcknowledgedResponse read(StreamInput in) throws IOException {
+        return new AcknowledgedResponse(in);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        DeleteSearchPipelineRequest request,
+        ClusterState state,
+        ActionListener<AcknowledgedResponse> listener
+    ) throws Exception {
+        searchPipelineService.deletePipeline(request, listener);
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(DeleteSearchPipelineRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/DfsQueryPhase.java b/server/src/main/java/org/opensearch/action/search/DfsQueryPhase.java
index 6152f4cfdc599..6fe4eaabd6d17 100644
--- a/server/src/main/java/org/opensearch/action/search/DfsQueryPhase.java
+++ b/server/src/main/java/org/opensearch/action/search/DfsQueryPhase.java
@@ -50,6 +50,8 @@
  * retry on another shard if any of the shards are failing. Failures are treated as shard failures and are counted as a non-successful
  * operation.
  * @see CountedCollector#onFailure(int, SearchShardTarget, Exception)
+ *
+ * @opensearch.internal
  */
 final class DfsQueryPhase extends SearchPhase {
     private final ArraySearchPhaseResults<SearchPhaseResult> queryResult;
@@ -67,7 +69,7 @@ final class DfsQueryPhase extends SearchPhase {
         Function<ArraySearchPhaseResults<SearchPhaseResult>, SearchPhase> nextPhaseFactory,
         SearchPhaseContext context
     ) {
-        super("dfs_query");
+        super(SearchPhaseName.DFS_QUERY.getName());
         this.progressListener = context.getTask().getProgressListener();
         this.queryResult = queryResult;
         this.searchResults = searchResults;
diff --git a/server/src/main/java/org/opensearch/action/search/ExpandSearchPhase.java b/server/src/main/java/org/opensearch/action/search/ExpandSearchPhase.java
index 6c131697cb31e..e249fb239dae9 100644
--- a/server/src/main/java/org/opensearch/action/search/ExpandSearchPhase.java
+++ b/server/src/main/java/org/opensearch/action/search/ExpandSearchPhase.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.QueryBuilder;
@@ -53,6 +53,8 @@
  * This search phase is an optional phase that will be executed once all hits are fetched from the shards that executes
  * field-collapsing on the inner hits. This phase only executes if field collapsing is requested in the search request and otherwise
  * forwards to the next phase immediately.
+ *
+ * @opensearch.internal
  */
 final class ExpandSearchPhase extends SearchPhase {
     private final SearchPhaseContext context;
@@ -60,7 +62,7 @@ final class ExpandSearchPhase extends SearchPhase {
     private final AtomicArray<SearchPhaseResult> queryResults;
 
     ExpandSearchPhase(SearchPhaseContext context, InternalSearchResponse searchResponse, AtomicArray<SearchPhaseResult> queryResults) {
-        super("expand");
+        super(SearchPhaseName.EXPAND.getName());
         this.context = context;
         this.searchResponse = searchResponse;
         this.queryResults = queryResults;
diff --git a/server/src/main/java/org/opensearch/action/search/FetchSearchPhase.java b/server/src/main/java/org/opensearch/action/search/FetchSearchPhase.java
index c106c5e2f8069..ebb2f33f8f37d 100644
--- a/server/src/main/java/org/opensearch/action/search/FetchSearchPhase.java
+++ b/server/src/main/java/org/opensearch/action/search/FetchSearchPhase.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.search;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.search.ScoreDoc;
@@ -56,6 +55,8 @@
 /**
  * This search phase merges the query results from the previous phase together and calculates the topN hits for this search.
  * Then it reaches out to all relevant shards to fetch the topN hits.
+ *
+ * @opensearch.internal
  */
 final class FetchSearchPhase extends SearchPhase {
     private final ArraySearchPhaseResults<FetchSearchResult> fetchResults;
@@ -90,7 +91,7 @@ final class FetchSearchPhase extends SearchPhase {
         SearchPhaseContext context,
         BiFunction<InternalSearchResponse, AtomicArray<SearchPhaseResult>, SearchPhase> nextPhaseFactory
     ) {
-        super("fetch");
+        super(SearchPhaseName.FETCH.getName());
         if (context.getNumShards() != resultConsumer.getNumShards()) {
             throw new IllegalStateException(
                 "number of shards must match the length of the query results but doesn't:"
@@ -149,7 +150,7 @@ private void innerRun() throws Exception {
             finishPhase.run();
         } else {
             ScoreDoc[] scoreDocs = reducedQueryPhase.sortedTopDocs.scoreDocs;
-            final IntArrayList[] docIdsToLoad = searchPhaseController.fillDocIdsToLoad(numShards, scoreDocs);
+            final List<Integer>[] docIdsToLoad = searchPhaseController.fillDocIdsToLoad(numShards, scoreDocs);
             // no docs to fetch -- sidestep everything and return
             if (scoreDocs.length == 0) {
                 // we have to release contexts here to free up resources
@@ -166,7 +167,7 @@ private void innerRun() throws Exception {
                     context
                 );
                 for (int i = 0; i < docIdsToLoad.length; i++) {
-                    IntArrayList entry = docIdsToLoad[i];
+                    List<Integer> entry = docIdsToLoad[i];
                     SearchPhaseResult queryResult = queryResults.get(i);
                     if (entry == null) { // no results for this shard ID
                         if (queryResult != null) {
@@ -203,7 +204,7 @@ private void innerRun() throws Exception {
     protected ShardFetchSearchRequest createFetchRequest(
         ShardSearchContextId contextId,
         int index,
-        IntArrayList entry,
+        List<Integer> entry,
         ScoreDoc[] lastEmittedDocPerShard,
         OriginalIndices originalIndices,
         ShardSearchRequest shardSearchRequest,
diff --git a/server/src/main/java/org/opensearch/action/search/GetAllPitNodeRequest.java b/server/src/main/java/org/opensearch/action/search/GetAllPitNodeRequest.java
new file mode 100644
index 0000000000000..4a5155f4e7b70
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetAllPitNodeRequest.java
@@ -0,0 +1,35 @@
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.nodes.BaseNodeRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Inner node get all pits request
+ */
+public class GetAllPitNodeRequest extends BaseNodeRequest {
+
+    public GetAllPitNodeRequest() {
+        super();
+    }
+
+    public GetAllPitNodeRequest(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetAllPitNodeResponse.java b/server/src/main/java/org/opensearch/action/search/GetAllPitNodeResponse.java
new file mode 100644
index 0000000000000..9bbc81c0d6a4c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetAllPitNodeResponse.java
@@ -0,0 +1,69 @@
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.nodes.BaseNodeResponse;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Inner node get all pits response
+ */
+public class GetAllPitNodeResponse extends BaseNodeResponse implements ToXContentFragment {
+
+    /**
+     * List of active PITs in the associated node
+     */
+    private final List<ListPitInfo> pitInfos;
+
+    public GetAllPitNodeResponse(DiscoveryNode node, List<ListPitInfo> pitInfos) {
+        super(node);
+        if (pitInfos == null) {
+            throw new IllegalArgumentException("Pits info cannot be null");
+        }
+        this.pitInfos = Collections.unmodifiableList(pitInfos);
+    }
+
+    public GetAllPitNodeResponse(StreamInput in) throws IOException {
+        super(in);
+        this.pitInfos = Collections.unmodifiableList(in.readList(ListPitInfo::new));
+    }
+
+    public List<ListPitInfo> getPitInfos() {
+        return pitInfos;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeList(pitInfos);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("node", this.getNode().getName());
+        builder.startArray("pitInfos");
+        for (ListPitInfo pit : pitInfos) {
+            pit.toXContent(builder, params);
+        }
+
+        builder.endArray();
+        builder.endObject();
+        return builder;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetAllPitNodesRequest.java b/server/src/main/java/org/opensearch/action/search/GetAllPitNodesRequest.java
new file mode 100644
index 0000000000000..948fe72eae817
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetAllPitNodesRequest.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.nodes.BaseNodesRequest;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Request to get all active PIT IDs from all nodes of cluster
+ */
+public class GetAllPitNodesRequest extends BaseNodesRequest<GetAllPitNodesRequest> {
+
+    @Inject
+    public GetAllPitNodesRequest(DiscoveryNode... concreteNodes) {
+        super(concreteNodes);
+    }
+
+    public GetAllPitNodesRequest(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetAllPitNodesResponse.java b/server/src/main/java/org/opensearch/action/search/GetAllPitNodesResponse.java
new file mode 100644
index 0000000000000..9bb3ab6407696
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetAllPitNodesResponse.java
@@ -0,0 +1,139 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.FailedNodeException;
+import org.opensearch.action.support.nodes.BaseNodesResponse;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * This class transforms active PIT objects from all nodes to unique PIT objects
+ */
+public class GetAllPitNodesResponse extends BaseNodesResponse<GetAllPitNodeResponse> implements ToXContentObject {
+
+    /**
+     * List of unique PITs across all nodes
+     */
+    private final Set<ListPitInfo> pitInfos = new HashSet<>();
+
+    public GetAllPitNodesResponse(StreamInput in) throws IOException {
+        super(in);
+        Set<String> uniquePitIds = new HashSet<>();
+        pitInfos.addAll(
+            getNodes().stream()
+                .flatMap(p -> p.getPitInfos().stream().filter(t -> uniquePitIds.add(t.getPitId())))
+                .collect(Collectors.toList())
+        );
+    }
+
+    public GetAllPitNodesResponse(
+        ClusterName clusterName,
+        List<GetAllPitNodeResponse> getAllPitNodeResponseList,
+        List<FailedNodeException> failures
+    ) {
+        super(clusterName, getAllPitNodeResponseList, failures);
+        Set<String> uniquePitIds = new HashSet<>();
+        pitInfos.addAll(
+            getAllPitNodeResponseList.stream()
+                .flatMap(p -> p.getPitInfos().stream().filter(t -> uniquePitIds.add(t.getPitId())))
+                .collect(Collectors.toList())
+        );
+    }
+
+    /**
+     * Copy constructor that explicitly sets the list pit infos
+     */
+    public GetAllPitNodesResponse(List<ListPitInfo> listPitInfos, GetAllPitNodesResponse response) {
+        super(response.getClusterName(), response.getNodes(), response.failures());
+        pitInfos.addAll(listPitInfos);
+    }
+
+    public GetAllPitNodesResponse(
+        List<ListPitInfo> listPitInfos,
+        ClusterName clusterName,
+        List<GetAllPitNodeResponse> getAllPitNodeResponseList,
+        List<FailedNodeException> failures
+    ) {
+        super(clusterName, getAllPitNodeResponseList, failures);
+        pitInfos.addAll(listPitInfos);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.startArray("pits");
+        for (ListPitInfo pit : pitInfos) {
+            pit.toXContent(builder, params);
+        }
+        builder.endArray();
+        if (!failures().isEmpty()) {
+            builder.startArray("failures");
+            for (FailedNodeException e : failures()) {
+                e.toXContent(builder, params);
+            }
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public List<GetAllPitNodeResponse> readNodesFrom(StreamInput in) throws IOException {
+        return in.readList(GetAllPitNodeResponse::new);
+    }
+
+    @Override
+    public void writeNodesTo(StreamOutput out, List<GetAllPitNodeResponse> nodes) throws IOException {
+        out.writeList(nodes);
+    }
+
+    public List<ListPitInfo> getPitInfos() {
+        return Collections.unmodifiableList(new ArrayList<>(pitInfos));
+    }
+
+    private static final ConstructingObjectParser<GetAllPitNodesResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "get_all_pits_response",
+        true,
+        (Object[] parsedObjects) -> {
+            @SuppressWarnings("unchecked")
+            List<ListPitInfo> listPitInfos = (List<ListPitInfo>) parsedObjects[0];
+            List<FailedNodeException> failures = null;
+            if (parsedObjects.length > 1) {
+                failures = (List<FailedNodeException>) parsedObjects[1];
+            }
+            if (failures == null) {
+                failures = new ArrayList<>();
+            }
+            return new GetAllPitNodesResponse(listPitInfos, new ClusterName(""), new ArrayList<>(), failures);
+        }
+    );
+    static {
+        PARSER.declareObjectArray(constructorArg(), ListPitInfo.PARSER, new ParseField("pits"));
+    }
+
+    public static GetAllPitNodesResponse fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetAllPitsAction.java b/server/src/main/java/org/opensearch/action/search/GetAllPitsAction.java
new file mode 100644
index 0000000000000..8fe901add5e3a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetAllPitsAction.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action type for retrieving all PIT reader contexts from nodes
+ */
+public class GetAllPitsAction extends ActionType<GetAllPitNodesResponse> {
+    public static final GetAllPitsAction INSTANCE = new GetAllPitsAction();
+    public static final String NAME = "indices:data/read/point_in_time/readall";
+
+    private GetAllPitsAction() {
+        super(NAME, GetAllPitNodesResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetSearchPipelineAction.java b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineAction.java
new file mode 100644
index 0000000000000..b80ffa781b0ec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Action type to get search pipelines
+ *
+ * @opensearch.internal
+ */
+public class GetSearchPipelineAction extends ActionType<GetSearchPipelineResponse> {
+    public static final GetSearchPipelineAction INSTANCE = new GetSearchPipelineAction();
+    public static final String NAME = "cluster:admin/search/pipeline/get";
+
+    public GetSearchPipelineAction() {
+        super(NAME, GetSearchPipelineResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetSearchPipelineRequest.java b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineRequest.java
new file mode 100644
index 0000000000000..f573a37fa5dab
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineRequest.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request to get search pipelines
+ *
+ * @opensearch.internal
+ */
+public class GetSearchPipelineRequest extends ClusterManagerNodeReadRequest<GetSearchPipelineRequest> {
+    private final String[] ids;
+
+    public GetSearchPipelineRequest(String... ids) {
+        this.ids = Objects.requireNonNull(ids);
+    }
+
+    public GetSearchPipelineRequest() {
+        ids = Strings.EMPTY_ARRAY;
+    }
+
+    public GetSearchPipelineRequest(StreamInput in) throws IOException {
+        super(in);
+        ids = in.readStringArray();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(ids);
+    }
+
+    public String[] getIds() {
+        return ids;
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetSearchPipelineResponse.java b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineResponse.java
new file mode 100644
index 0000000000000..64dde763e9ff8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineResponse.java
@@ -0,0 +1,144 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.common.xcontent.StatusToXContentObject;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.search.pipeline.PipelineConfiguration;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * transport response for getting a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class GetSearchPipelineResponse extends ActionResponse implements StatusToXContentObject {
+
+    private final List<PipelineConfiguration> pipelines;
+
+    public GetSearchPipelineResponse(StreamInput in) throws IOException {
+        super(in);
+        int size = in.readVInt();
+        pipelines = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            pipelines.add(PipelineConfiguration.readFrom(in));
+        }
+
+    }
+
+    public GetSearchPipelineResponse(List<PipelineConfiguration> pipelines) {
+        this.pipelines = pipelines;
+    }
+
+    public List<PipelineConfiguration> pipelines() {
+        return Collections.unmodifiableList(pipelines);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        for (PipelineConfiguration pipeline : pipelines) {
+            builder.field(pipeline.getId(), pipeline.getConfigAsMap());
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     *
+     * @param parser the parser for the XContent that contains the serialized GetPipelineResponse.
+     * @return an instance of GetPipelineResponse read from the parser
+     * @throws IOException If the parsing fails
+     */
+    public static GetSearchPipelineResponse fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        List<PipelineConfiguration> pipelines = new ArrayList<>();
+        while (parser.nextToken().equals(XContentParser.Token.FIELD_NAME)) {
+            String pipelineId = parser.currentName();
+            parser.nextToken();
+            try (XContentBuilder contentBuilder = XContentBuilder.builder(parser.contentType().xContent())) {
+                contentBuilder.generator().copyCurrentStructure(parser);
+                PipelineConfiguration pipeline = new PipelineConfiguration(
+                    pipelineId,
+                    BytesReference.bytes(contentBuilder),
+                    contentBuilder.contentType()
+                );
+                pipelines.add(pipeline);
+            }
+        }
+        ensureExpectedToken(XContentParser.Token.END_OBJECT, parser.currentToken(), parser);
+        return new GetSearchPipelineResponse(pipelines);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVInt(pipelines.size());
+        for (PipelineConfiguration pipeline : pipelines) {
+            pipeline.writeTo(out);
+        }
+    }
+
+    public boolean isFound() {
+        return !pipelines.isEmpty();
+    }
+
+    @Override
+    public RestStatus status() {
+        return isFound() ? RestStatus.OK : RestStatus.NOT_FOUND;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        GetSearchPipelineResponse otherResponse = (GetSearchPipelineResponse) o;
+        if (pipelines == null) {
+            return otherResponse.pipelines == null;
+        } else if (otherResponse.pipelines == null) {
+            return false;
+        }
+        // Convert to a map to ignore order;
+        return toMap(pipelines).equals(toMap(otherResponse.pipelines));
+    }
+
+    private static Map<String, PipelineConfiguration> toMap(List<PipelineConfiguration> pipelines) {
+        return pipelines.stream().collect(Collectors.toMap(PipelineConfiguration::getId, p -> p));
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 1;
+        for (PipelineConfiguration pipeline : pipelines) {
+            // We only take the sum here to ensure that the order does not matter.
+            result += (pipeline == null ? 0 : pipeline.hashCode());
+        }
+        return result;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/GetSearchPipelineTransportAction.java b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineTransportAction.java
new file mode 100644
index 0000000000000..a7fcb8f1cfbae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/GetSearchPipelineTransportAction.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+
+/**
+ * Perform the action of getting a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class GetSearchPipelineTransportAction extends TransportClusterManagerNodeReadAction<
+    GetSearchPipelineRequest,
+    GetSearchPipelineResponse> {
+
+    @Inject
+    public GetSearchPipelineTransportAction(
+        ThreadPool threadPool,
+        ClusterService clusterService,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            GetSearchPipelineAction.NAME,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            GetSearchPipelineRequest::new,
+            indexNameExpressionResolver
+        );
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected GetSearchPipelineResponse read(StreamInput in) throws IOException {
+        return new GetSearchPipelineResponse(in);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        GetSearchPipelineRequest request,
+        ClusterState state,
+        ActionListener<GetSearchPipelineResponse> listener
+    ) throws Exception {
+        listener.onResponse(new GetSearchPipelineResponse(SearchPipelineService.getPipelines(state, request.getIds())));
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(GetSearchPipelineRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/ListPitInfo.java b/server/src/main/java/org/opensearch/action/search/ListPitInfo.java
new file mode 100644
index 0000000000000..220b7247517b9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/ListPitInfo.java
@@ -0,0 +1,97 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
+/**
+ * This holds information about pit reader context such as pit id and creation time
+ */
+public class ListPitInfo implements ToXContentFragment, Writeable {
+    private final String pitId;
+    private final long creationTime;
+    private final long keepAlive;
+
+    public ListPitInfo(String pitId, long creationTime, long keepAlive) {
+        this.pitId = pitId;
+        this.creationTime = creationTime;
+        this.keepAlive = keepAlive;
+    }
+
+    public ListPitInfo(StreamInput in) throws IOException {
+        this.pitId = in.readString();
+        this.creationTime = in.readLong();
+        this.keepAlive = in.readLong();
+    }
+
+    public String getPitId() {
+        return pitId;
+    }
+
+    public long getCreationTime() {
+        return creationTime;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(pitId);
+        out.writeLong(creationTime);
+        out.writeLong(keepAlive);
+    }
+
+    static final ConstructingObjectParser<ListPitInfo, Void> PARSER = new ConstructingObjectParser<>(
+        "list_pit_info",
+        true,
+        args -> new ListPitInfo((String) args[0], (long) args[1], (long) args[2])
+    );
+
+    private static final ParseField CREATION_TIME = new ParseField("creation_time");
+    private static final ParseField PIT_ID = new ParseField("pit_id");
+    private static final ParseField KEEP_ALIVE = new ParseField("keep_alive");
+    static {
+        PARSER.declareString(constructorArg(), PIT_ID);
+        PARSER.declareLong(constructorArg(), CREATION_TIME);
+        PARSER.declareLong(constructorArg(), KEEP_ALIVE);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field(PIT_ID.getPreferredName(), pitId);
+        builder.field(CREATION_TIME.getPreferredName(), creationTime);
+        builder.field(KEEP_ALIVE.getPreferredName(), keepAlive);
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ListPitInfo that = (ListPitInfo) o;
+        return pitId.equals(that.pitId) && creationTime == that.creationTime && keepAlive == that.keepAlive;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(pitId, creationTime, keepAlive);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/MaxScoreCollector.java b/server/src/main/java/org/opensearch/action/search/MaxScoreCollector.java
index fce1de8cecbda..d7e0ba6d30fec 100644
--- a/server/src/main/java/org/opensearch/action/search/MaxScoreCollector.java
+++ b/server/src/main/java/org/opensearch/action/search/MaxScoreCollector.java
@@ -40,6 +40,8 @@
 
 /**
  * A collector that computes the maximum score.
+ *
+ * @opensearch.internal
  */
 public class MaxScoreCollector extends SimpleCollector {
 
diff --git a/server/src/main/java/org/opensearch/action/search/MultiSearchAction.java b/server/src/main/java/org/opensearch/action/search/MultiSearchAction.java
index fc8416536bf0a..84c18855324a9 100644
--- a/server/src/main/java/org/opensearch/action/search/MultiSearchAction.java
+++ b/server/src/main/java/org/opensearch/action/search/MultiSearchAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for executing a multi search
+ *
+ * @opensearch.internal
+ */
 public class MultiSearchAction extends ActionType<MultiSearchResponse> {
 
     public static final MultiSearchAction INSTANCE = new MultiSearchAction();
diff --git a/server/src/main/java/org/opensearch/action/search/MultiSearchRequest.java b/server/src/main/java/org/opensearch/action/search/MultiSearchRequest.java
index c45b6477d30f0..da8f8f144eaf2 100644
--- a/server/src/main/java/org/opensearch/action/search/MultiSearchRequest.java
+++ b/server/src/main/java/org/opensearch/action/search/MultiSearchRequest.java
@@ -38,19 +38,19 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.IndicesOptions.WildcardStates;
 import org.opensearch.common.CheckedBiConsumer;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -70,6 +70,8 @@
 
 /**
  * A multi search API request.
+ *
+ * @opensearch.internal
  */
 public class MultiSearchRequest extends ActionRequest implements CompositeIndicesRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/search/MultiSearchRequestBuilder.java b/server/src/main/java/org/opensearch/action/search/MultiSearchRequestBuilder.java
index e8db52b949425..f9bb90c69d925 100644
--- a/server/src/main/java/org/opensearch/action/search/MultiSearchRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/search/MultiSearchRequestBuilder.java
@@ -38,6 +38,8 @@
 
 /**
  * A request builder for multiple search requests.
+ *
+ * @opensearch.internal
  */
 public class MultiSearchRequestBuilder extends ActionRequestBuilder<MultiSearchRequest, MultiSearchResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/search/MultiSearchResponse.java b/server/src/main/java/org/opensearch/action/search/MultiSearchResponse.java
index 3869d909cce6e..89a053133abb9 100644
--- a/server/src/main/java/org/opensearch/action/search/MultiSearchResponse.java
+++ b/server/src/main/java/org/opensearch/action/search/MultiSearchResponse.java
@@ -32,32 +32,35 @@
 
 package org.opensearch.action.search;
 
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A multi search response.
+ *
+ * @opensearch.internal
  */
 public class MultiSearchResponse extends ActionResponse implements Iterable<MultiSearchResponse.Item>, ToXContentObject {
 
@@ -75,6 +78,8 @@ public class MultiSearchResponse extends ActionResponse implements Iterable<Mult
 
     /**
      * A search response item, holding the actual search response, or an error message if it failed.
+     *
+     * @opensearch.internal
      */
     public static class Item implements Writeable {
         private final SearchResponse response;
@@ -245,6 +250,11 @@ private static MultiSearchResponse.Item itemFromXContent(XContentParser parser)
         return item;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String RESPONSES = "responses";
         static final String STATUS = "status";
@@ -252,6 +262,6 @@ static final class Fields {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/search/ParsedScrollId.java b/server/src/main/java/org/opensearch/action/search/ParsedScrollId.java
index 1a9eaf7e6716f..70be9a0b19e08 100644
--- a/server/src/main/java/org/opensearch/action/search/ParsedScrollId.java
+++ b/server/src/main/java/org/opensearch/action/search/ParsedScrollId.java
@@ -34,6 +34,11 @@
 
 import java.util.Arrays;
 
+/**
+ * Search scroll id that has been parsed
+ *
+ * @opensearch.internal
+ */
 public class ParsedScrollId {
 
     public static final String QUERY_THEN_FETCH_TYPE = "queryThenFetch";
diff --git a/server/src/main/java/org/opensearch/action/search/PitSearchContextIdForNode.java b/server/src/main/java/org/opensearch/action/search/PitSearchContextIdForNode.java
new file mode 100644
index 0000000000000..b885d3b351e80
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/PitSearchContextIdForNode.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+
+/**
+ * Pit ID along with Id for a search context per node.
+ *
+ * @opensearch.internal
+ */
+public class PitSearchContextIdForNode implements Writeable {
+
+    private final String pitId;
+    private final SearchContextIdForNode searchContextIdForNode;
+
+    public PitSearchContextIdForNode(String pitId, SearchContextIdForNode searchContextIdForNode) {
+        this.pitId = pitId;
+        this.searchContextIdForNode = searchContextIdForNode;
+    }
+
+    PitSearchContextIdForNode(StreamInput in) throws IOException {
+        this.pitId = in.readString();
+        this.searchContextIdForNode = new SearchContextIdForNode(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(pitId);
+        searchContextIdForNode.writeTo(out);
+    }
+
+    public String getPitId() {
+        return pitId;
+    }
+
+    public SearchContextIdForNode getSearchContextIdForNode() {
+        return searchContextIdForNode;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/PitService.java b/server/src/main/java/org/opensearch/action/search/PitService.java
new file mode 100644
index 0000000000000..b7c849b840504
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/PitService.java
@@ -0,0 +1,207 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.StepListener;
+import org.opensearch.action.support.GroupedActionListener;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transport;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.BiFunction;
+import java.util.stream.Collectors;
+
+/**
+ * Service class for PIT reusable functions
+ */
+public class PitService {
+
+    private static final Logger logger = LogManager.getLogger(PitService.class);
+
+    private final ClusterService clusterService;
+    private final SearchTransportService searchTransportService;
+    private final TransportService transportService;
+    private final NodeClient nodeClient;
+
+    @Inject
+    public PitService(
+        ClusterService clusterService,
+        SearchTransportService searchTransportService,
+        TransportService transportService,
+        NodeClient nodeClient
+    ) {
+        this.clusterService = clusterService;
+        this.searchTransportService = searchTransportService;
+        this.transportService = transportService;
+        this.nodeClient = nodeClient;
+    }
+
+    /**
+     * Delete list of pit contexts. Returns the details of success of operation per PIT ID.
+     */
+    public void deletePitContexts(
+        Map<String, List<PitSearchContextIdForNode>> nodeToContextsMap,
+        ActionListener<DeletePitResponse> listener
+    ) {
+        if (nodeToContextsMap.size() == 0) {
+            listener.onResponse(new DeletePitResponse(Collections.emptyList()));
+        }
+        final Set<String> clusters = nodeToContextsMap.values()
+            .stream()
+            .flatMap(Collection::stream)
+            .filter(ctx -> Strings.isEmpty(ctx.getSearchContextIdForNode().getClusterAlias()) == false)
+            .map(c -> c.getSearchContextIdForNode().getClusterAlias())
+            .collect(Collectors.toSet());
+        StepListener<BiFunction<String, String, DiscoveryNode>> lookupListener = (StepListener<
+            BiFunction<String, String, DiscoveryNode>>) SearchUtils.getConnectionLookupListener(
+                searchTransportService.getRemoteClusterService(),
+                clusterService.state(),
+                clusters
+            );
+        lookupListener.whenComplete(nodeLookup -> {
+            final GroupedActionListener<DeletePitResponse> groupedListener = getDeletePitGroupedListener(
+                listener,
+                nodeToContextsMap.size()
+            );
+
+            for (Map.Entry<String, List<PitSearchContextIdForNode>> entry : nodeToContextsMap.entrySet()) {
+                String clusterAlias = entry.getValue().get(0).getSearchContextIdForNode().getClusterAlias();
+                DiscoveryNode node = nodeLookup.apply(clusterAlias, entry.getValue().get(0).getSearchContextIdForNode().getNode());
+                if (node == null) {
+                    node = this.clusterService.state().getNodes().get(entry.getValue().get(0).getSearchContextIdForNode().getNode());
+                }
+                if (node == null) {
+                    logger.error(
+                        () -> new ParameterizedMessage("node [{}] not found", entry.getValue().get(0).getSearchContextIdForNode().getNode())
+                    );
+                    List<DeletePitInfo> deletePitInfos = new ArrayList<>();
+                    for (PitSearchContextIdForNode pitSearchContextIdForNode : entry.getValue()) {
+                        deletePitInfos.add(new DeletePitInfo(false, pitSearchContextIdForNode.getPitId()));
+                    }
+                    groupedListener.onResponse(new DeletePitResponse(deletePitInfos));
+                } else {
+                    try {
+                        final Transport.Connection connection = searchTransportService.getConnection(clusterAlias, node);
+                        searchTransportService.sendFreePITContexts(connection, entry.getValue(), groupedListener);
+                    } catch (Exception e) {
+                        String nodeName = node.getName();
+                        logger.error(() -> new ParameterizedMessage("Delete PITs failed on node [{}]", nodeName), e);
+                        List<DeletePitInfo> deletePitInfos = new ArrayList<>();
+                        for (PitSearchContextIdForNode pitSearchContextIdForNode : entry.getValue()) {
+                            deletePitInfos.add(new DeletePitInfo(false, pitSearchContextIdForNode.getPitId()));
+                        }
+                        groupedListener.onResponse(new DeletePitResponse(deletePitInfos));
+                    }
+                }
+            }
+        }, listener::onFailure);
+    }
+
+    public GroupedActionListener<DeletePitResponse> getDeletePitGroupedListener(ActionListener<DeletePitResponse> listener, int size) {
+        return new GroupedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(final Collection<DeletePitResponse> responses) {
+                Map<String, Boolean> pitIdToSucceededMap = new HashMap<>();
+                for (DeletePitResponse response : responses) {
+                    for (DeletePitInfo deletePitInfo : response.getDeletePitResults()) {
+                        if (!pitIdToSucceededMap.containsKey(deletePitInfo.getPitId())) {
+                            pitIdToSucceededMap.put(deletePitInfo.getPitId(), deletePitInfo.isSuccessful());
+                        }
+                        if (!deletePitInfo.isSuccessful()) {
+                            logger.debug(() -> new ParameterizedMessage("Deleting PIT with ID {} failed ", deletePitInfo.getPitId()));
+                            pitIdToSucceededMap.put(deletePitInfo.getPitId(), deletePitInfo.isSuccessful());
+                        }
+                    }
+                }
+                List<DeletePitInfo> deletePitResults = new ArrayList<>();
+                for (Map.Entry<String, Boolean> entry : pitIdToSucceededMap.entrySet()) {
+                    deletePitResults.add(new DeletePitInfo(entry.getValue(), entry.getKey()));
+                }
+                DeletePitResponse deletePitResponse = new DeletePitResponse(deletePitResults);
+                listener.onResponse(deletePitResponse);
+            }
+
+            @Override
+            public void onFailure(final Exception e) {
+                logger.error("Delete PITs failed", e);
+                listener.onFailure(e);
+            }
+        }, size);
+    }
+
+    /**
+     * This method returns indices associated for each pit
+     */
+    public Map<String, String[]> getIndicesForPits(List<String> pitIds) {
+        Map<String, String[]> pitToIndicesMap = new HashMap<>();
+        for (String pitId : pitIds) {
+            pitToIndicesMap.put(pitId, SearchContextId.decode(nodeClient.getNamedWriteableRegistry(), pitId).getActualIndices());
+        }
+        return pitToIndicesMap;
+    }
+
+    /**
+     * Get all active point in time contexts
+     */
+    public void getAllPits(ActionListener<GetAllPitNodesResponse> getAllPitsListener) {
+        final List<DiscoveryNode> nodes = new ArrayList<>();
+        for (final DiscoveryNode node : clusterService.state().nodes().getDataNodes().values()) {
+            nodes.add(node);
+        }
+        DiscoveryNode[] disNodesArr = nodes.toArray(new DiscoveryNode[nodes.size()]);
+        GetAllPitNodesRequest getAllPitNodesRequest = new GetAllPitNodesRequest(disNodesArr);
+        transportService.sendRequest(
+            transportService.getLocalNode(),
+            GetAllPitsAction.NAME,
+            getAllPitNodesRequest,
+            new TransportResponseHandler<GetAllPitNodesResponse>() {
+
+                @Override
+                public void handleResponse(GetAllPitNodesResponse response) {
+                    getAllPitsListener.onResponse(response);
+                }
+
+                @Override
+                public void handleException(TransportException exp) {
+                    getAllPitsListener.onFailure(exp);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.SAME;
+                }
+
+                @Override
+                public GetAllPitNodesResponse read(StreamInput in) throws IOException {
+                    return new GetAllPitNodesResponse(in);
+                }
+            }
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/PutSearchPipelineAction.java b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineAction.java
new file mode 100644
index 0000000000000..798c8211ee505
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineAction.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.ActionType;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+
+/**
+ * Action type to put a new search pipeline
+ *
+ * @opensearch.internal
+ */
+public class PutSearchPipelineAction extends ActionType<AcknowledgedResponse> {
+    public static final PutSearchPipelineAction INSTANCE = new PutSearchPipelineAction();
+    public static final String NAME = "cluster:admin/search/pipeline/put";
+
+    public PutSearchPipelineAction() {
+        super(NAME, AcknowledgedResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java
new file mode 100644
index 0000000000000..48cf8e5028f90
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.Version;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.master.AcknowledgedRequest;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request to put a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class PutSearchPipelineRequest extends AcknowledgedRequest<PutSearchPipelineRequest> implements ToXContentObject {
+    private String id;
+    private BytesReference source;
+    private MediaType mediaType;
+
+    public PutSearchPipelineRequest(String id, BytesReference source, MediaType mediaType) {
+        this.id = Objects.requireNonNull(id);
+        this.source = Objects.requireNonNull(source);
+        if (mediaType instanceof XContentType == false) {
+            throw new IllegalArgumentException(
+                PutSearchPipelineRequest.class.getSimpleName() + " found unsupported media type [" + mediaType.getClass().getName() + "]"
+            );
+        }
+        this.mediaType = Objects.requireNonNull(mediaType);
+    }
+
+    public PutSearchPipelineRequest(StreamInput in) throws IOException {
+        super(in);
+        id = in.readString();
+        source = in.readBytesReference();
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public BytesReference getSource() {
+        return source;
+    }
+
+    public MediaType getMediaType() {
+        return mediaType;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(id);
+        out.writeBytesReference(source);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        if (source != null) {
+            builder.rawValue(source.streamInput(), mediaType);
+        } else {
+            builder.startObject().endObject();
+        }
+        return builder;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/PutSearchPipelineTransportAction.java b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineTransportAction.java
new file mode 100644
index 0000000000000..a92961cdc3fd9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineTransportAction.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.admin.cluster.node.info.NodeInfo;
+import org.opensearch.action.admin.cluster.node.info.NodesInfoRequest;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.OriginSettingClient;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.search.pipeline.SearchPipelineInfo;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.search.pipeline.SearchPipelineService.SEARCH_PIPELINE_ORIGIN;
+
+/**
+ * Perform the action of putting a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class PutSearchPipelineTransportAction extends TransportClusterManagerNodeAction<PutSearchPipelineRequest, AcknowledgedResponse> {
+
+    private final SearchPipelineService searchPipelineService;
+    private final OriginSettingClient client;
+
+    @Inject
+    public PutSearchPipelineTransportAction(
+        ThreadPool threadPool,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        SearchPipelineService searchPipelineService,
+        NodeClient client
+    ) {
+        super(
+            PutSearchPipelineAction.NAME,
+            transportService,
+            searchPipelineService.getClusterService(),
+            threadPool,
+            actionFilters,
+            PutSearchPipelineRequest::new,
+            indexNameExpressionResolver
+        );
+        this.client = new OriginSettingClient(client, SEARCH_PIPELINE_ORIGIN);
+        this.searchPipelineService = searchPipelineService;
+    }
+
+    @Override
+    protected String executor() {
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected AcknowledgedResponse read(StreamInput in) throws IOException {
+        return new AcknowledgedResponse(in);
+    }
+
+    @Override
+    protected void clusterManagerOperation(
+        PutSearchPipelineRequest request,
+        ClusterState state,
+        ActionListener<AcknowledgedResponse> listener
+    ) throws Exception {
+        NodesInfoRequest nodesInfoRequest = new NodesInfoRequest();
+        client.admin().cluster().nodesInfo(nodesInfoRequest, ActionListener.wrap(nodeInfos -> {
+            Map<DiscoveryNode, SearchPipelineInfo> searchPipelineInfos = new HashMap<>();
+            for (NodeInfo nodeInfo : nodeInfos.getNodes()) {
+                searchPipelineInfos.put(nodeInfo.getNode(), nodeInfo.getInfo(SearchPipelineInfo.class));
+            }
+            searchPipelineService.putPipeline(searchPipelineInfos, request, listener);
+        }, listener::onFailure));
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(PutSearchPipelineRequest request, ClusterState state) {
+        return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/QueryPhaseResultConsumer.java b/server/src/main/java/org/opensearch/action/search/QueryPhaseResultConsumer.java
index 02e6b54777f7f..f1b06378bd579 100644
--- a/server/src/main/java/org/opensearch/action/search/QueryPhaseResultConsumer.java
+++ b/server/src/main/java/org/opensearch/action/search/QueryPhaseResultConsumer.java
@@ -35,13 +35,13 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.TopDocs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContextBuilder;
@@ -66,6 +66,8 @@
  * in the {@link CircuitBreaker#REQUEST} circuit breaker. Before any partial or final reduce, the memory
  * needed to reduce the aggregations is estimated and a {@link CircuitBreakingException} is thrown if it
  * exceeds the maximum memory allowed in this breaker.
+ *
+ * @opensearch.internal
  */
 public class QueryPhaseResultConsumer extends ArraySearchPhaseResults<SearchPhaseResult> implements Releasable {
     private static final Logger logger = LogManager.getLogger(QueryPhaseResultConsumer.class);
@@ -240,6 +242,11 @@ public int getNumReducePhases() {
         return pendingMerges.numReducePhases;
     }
 
+    /**
+     * Class representing pending merges
+     *
+     * @opensearch.internal
+     */
     private class PendingMerges implements Releasable {
         private final int batchReduceSize;
         private final List<QuerySearchResult> buffer = new ArrayList<>();
@@ -496,6 +503,11 @@ public synchronized List<InternalAggregations> consumeAggs() {
         }
     }
 
+    /**
+     * A single merge result
+     *
+     * @opensearch.internal
+     */
     private static class MergeResult {
         private final List<SearchShard> processedShards;
         private final TopDocs reducedTopDocs;
@@ -515,6 +527,11 @@ private MergeResult(
         }
     }
 
+    /**
+     * A single merge task
+     *
+     * @opensearch.internal
+     */
     private static class MergeTask {
         private final List<SearchShard> emptyResults;
         private QuerySearchResult[] buffer;
diff --git a/server/src/main/java/org/opensearch/action/search/ReduceSearchPhaseException.java b/server/src/main/java/org/opensearch/action/search/ReduceSearchPhaseException.java
index 88558ceb6f7d9..27522280336ea 100644
--- a/server/src/main/java/org/opensearch/action/search/ReduceSearchPhaseException.java
+++ b/server/src/main/java/org/opensearch/action/search/ReduceSearchPhaseException.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
@@ -40,7 +40,7 @@
  * A failure during a reduce phase (when receiving results from several shards, and reducing them
  * into one or more results and possible actions).
  *
- *
+ * @opensearch.internal
  */
 public class ReduceSearchPhaseException extends SearchPhaseExecutionException {
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchAction.java b/server/src/main/java/org/opensearch/action/search/SearchAction.java
index e3a906f8b30ce..c94b3b7352196 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for executing a search
+ *
+ * @opensearch.internal
+ */
 public class SearchAction extends ActionType<SearchResponse> {
 
     public static final SearchAction INSTANCE = new SearchAction();
diff --git a/server/src/main/java/org/opensearch/action/search/SearchActionListener.java b/server/src/main/java/org/opensearch/action/search/SearchActionListener.java
index c081dba3fe9c5..c032012b0b45d 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchActionListener.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchActionListener.java
@@ -31,13 +31,15 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 
 /**
  * A base action listener that ensures shard target and shard index is set on all responses
  * received by this listener.
+ *
+ * @opensearch.internal
  */
 abstract class SearchActionListener<T extends SearchPhaseResult> implements ActionListener<T> {
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchContextId.java b/server/src/main/java/org/opensearch/action/search/SearchContextId.java
index 59ebb128b924a..41887f09e3fca 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchContextId.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchContextId.java
@@ -33,15 +33,15 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.AliasFilter;
@@ -57,6 +57,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Id for a serach context.
+ *
+ * @opensearch.internal
+ */
 public class SearchContextId {
     private final Map<ShardId, SearchContextIdForNode> shards;
     private final Map<String, AliasFilter> aliasFilter;
@@ -85,7 +90,7 @@ public static String encode(List<SearchPhaseResult> searchPhaseResults, Map<Stri
         }
         try (BytesStreamOutput out = new BytesStreamOutput()) {
             out.setVersion(version);
-            Version.writeVersion(version, out);
+            out.writeVersion(version);
             out.writeMap(shards, (o, k) -> k.writeTo(o), (o, v) -> v.writeTo(o));
             out.writeMap(aliasFilter, StreamOutput::writeString, (o, v) -> v.writeTo(o));
             return Base64.getUrlEncoder().encodeToString(BytesReference.toBytes(out.bytes()));
@@ -102,7 +107,7 @@ public static SearchContextId decode(NamedWriteableRegistry namedWriteableRegist
             throw new IllegalArgumentException("invalid id: [" + id + "]", e);
         }
         try (StreamInput in = new NamedWriteableAwareStreamInput(new ByteBufferStreamInput(byteBuffer), namedWriteableRegistry)) {
-            final Version version = Version.readVersion(in);
+            final Version version = in.readVersion();
             in.setVersion(version);
             final Map<ShardId, SearchContextIdForNode> shards = in.readMap(ShardId::new, SearchContextIdForNode::new);
             final Map<String, AliasFilter> aliasFilters = in.readMap(StreamInput::readString, AliasFilter::new);
@@ -111,7 +116,7 @@ public static SearchContextId decode(NamedWriteableRegistry namedWriteableRegist
             }
             return new SearchContextId(Collections.unmodifiableMap(shards), Collections.unmodifiableMap(aliasFilters));
         } catch (IOException e) {
-            throw new IllegalArgumentException(e);
+            throw new IllegalArgumentException("invalid id: [" + id + "]", e);
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchContextIdForNode.java b/server/src/main/java/org/opensearch/action/search/SearchContextIdForNode.java
index 379b268042e52..59c0e54bb6cbc 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchContextIdForNode.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchContextIdForNode.java
@@ -33,19 +33,24 @@
 package org.opensearch.action.search;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.internal.ShardSearchContextId;
 
 import java.io.IOException;
 
+/**
+ * Id for a search context per node.
+ *
+ * @opensearch.internal
+ */
 public final class SearchContextIdForNode implements Writeable {
     private final String node;
     private final ShardSearchContextId searchContextId;
     private final String clusterAlias;
 
-    SearchContextIdForNode(@Nullable String clusterAlias, String node, ShardSearchContextId searchContextId) {
+    public SearchContextIdForNode(@Nullable String clusterAlias, String node, ShardSearchContextId searchContextId) {
         this.node = node;
         this.clusterAlias = clusterAlias;
         this.searchContextId = searchContextId;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchDfsQueryThenFetchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/SearchDfsQueryThenFetchAsyncAction.java
index 50aac3daed52d..eca9646ee6b7c 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchDfsQueryThenFetchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchDfsQueryThenFetchAsyncAction.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.search;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.GroupShardsIterator;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.dfs.AggregatedDfs;
@@ -49,6 +49,11 @@
 import java.util.concurrent.Executor;
 import java.util.function.BiFunction;
 
+/**
+ * Async action for DFS Query Then Fetch
+ *
+ * @opensearch.internal
+ */
 final class SearchDfsQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<DfsSearchResult> {
 
     private final SearchPhaseController searchPhaseController;
@@ -71,10 +76,11 @@ final class SearchDfsQueryThenFetchAsyncAction extends AbstractSearchAsyncAction
         final TransportSearchAction.SearchTimeProvider timeProvider,
         final ClusterState clusterState,
         final SearchTask task,
-        SearchResponse.Clusters clusters
+        SearchResponse.Clusters clusters,
+        SearchRequestOperationsListener searchRequestOperationsListener
     ) {
         super(
-            "dfs",
+            SearchPhaseName.DFS_PRE_QUERY.getName(),
             logger,
             searchTransportService,
             nodeIdToConnection,
@@ -90,7 +96,8 @@ final class SearchDfsQueryThenFetchAsyncAction extends AbstractSearchAsyncAction
             task,
             new ArraySearchPhaseResults<>(shardsIts.size()),
             request.getMaxConcurrentShardRequests(),
-            clusters
+            clusters,
+            searchRequestOperationsListener
         );
         this.queryPhaseResultConsumer = queryPhaseResultConsumer;
         this.searchPhaseController = searchPhaseController;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchExecutionStatsCollector.java b/server/src/main/java/org/opensearch/action/search/SearchExecutionStatsCollector.java
index ce77a6368f2b6..842e87b3eb635 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchExecutionStatsCollector.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchExecutionStatsCollector.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.node.ResponseCollectorService;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.fetch.QueryFetchSearchResult;
@@ -46,6 +46,8 @@
  * A wrapper of search action listeners (search results) that unwraps the query
  * result to get the piggybacked queue size and service time EWMA, adding those
  * values to the coordinating nodes' {@link ResponseCollectorService}.
+ *
+ * @opensearch.internal
  */
 public final class SearchExecutionStatsCollector implements ActionListener<SearchPhaseResult> {
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhase.java b/server/src/main/java/org/opensearch/action/search/SearchPhase.java
index 18509a2694cd1..1c7b3c1f1563c 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchPhase.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhase.java
@@ -34,22 +34,44 @@
 import org.opensearch.common.CheckedRunnable;
 
 import java.io.IOException;
+import java.util.Locale;
 import java.util.Objects;
 
 /**
  * Base class for all individual search phases like collecting distributed frequencies, fetching documents, querying shards.
+ *
+ * @opensearch.internal
  */
-abstract class SearchPhase implements CheckedRunnable<IOException> {
+public abstract class SearchPhase implements CheckedRunnable<IOException> {
     private final String name;
+    private long startTimeInNanos;
 
     protected SearchPhase(String name) {
         this.name = Objects.requireNonNull(name, "name must not be null");
     }
 
+    public long getStartTimeInNanos() {
+        return startTimeInNanos;
+    }
+
+    public void recordAndRun() throws IOException {
+        this.startTimeInNanos = System.nanoTime();
+        run();
+    }
+
     /**
      * Returns the phases name.
      */
     public String getName() {
         return name;
     }
+
+    /**
+     * Returns the SearchPhase name as {@link SearchPhaseName}. Exception will come if SearchPhase name is not defined
+     * in {@link SearchPhaseName}
+     * @return {@link SearchPhaseName}
+     */
+    public SearchPhaseName getSearchPhaseName() {
+        return SearchPhaseName.valueOf(name.toUpperCase(Locale.ROOT));
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhaseContext.java b/server/src/main/java/org/opensearch/action/search/SearchPhaseContext.java
index 2f30d28a0924c..45d39a6f85ea2 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchPhaseContext.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhaseContext.java
@@ -47,8 +47,10 @@
 
 /**
  * This class provide contextual state and access to resources across multiple search phases.
+ *
+ * @opensearch.internal
  */
-interface SearchPhaseContext extends Executor {
+public interface SearchPhaseContext extends Executor {
     // TODO maybe we can make this concrete later - for now we just implement this in the base class for all initial phases
 
     /**
@@ -71,6 +73,8 @@ interface SearchPhaseContext extends Executor {
      */
     SearchRequest getRequest();
 
+    SearchPhase getCurrentPhase();
+
     /**
      * Builds and sends the final search response back to the user.
      *
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhaseController.java b/server/src/main/java/org/opensearch/action/search/SearchPhaseController.java
index 8c3b1d20b33a0..cca85f92d2676 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchPhaseController.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhaseController.java
@@ -32,25 +32,22 @@
 
 package org.opensearch.action.search;
 
-import com.carrotsearch.hppc.IntArrayList;
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.CollectionStatistics;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.TermStatistics;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.TotalHits.Relation;
 import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.collect.HppcMaps;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
@@ -68,6 +65,7 @@
 import org.opensearch.search.profile.ProfileShardResult;
 import org.opensearch.search.profile.SearchProfileShardResults;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.sort.SortedWiderNumericSortField;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggest.Suggestion;
 import org.opensearch.search.suggest.completion.CompletionSuggestion;
@@ -84,23 +82,28 @@
 import java.util.function.IntFunction;
 import java.util.stream.Collectors;
 
+/**
+ * Controller for the search phase.
+ *
+ * @opensearch.internal
+ */
 public final class SearchPhaseController {
     private static final ScoreDoc[] EMPTY_DOCS = new ScoreDoc[0];
 
     private final NamedWriteableRegistry namedWriteableRegistry;
-    private final Function<SearchRequest, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder;
+    private final Function<SearchSourceBuilder, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder;
 
     public SearchPhaseController(
         NamedWriteableRegistry namedWriteableRegistry,
-        Function<SearchRequest, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder
+        Function<SearchSourceBuilder, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder
     ) {
         this.namedWriteableRegistry = namedWriteableRegistry;
         this.requestToAggReduceContextBuilder = requestToAggReduceContextBuilder;
     }
 
     public AggregatedDfs aggregateDfs(Collection<DfsSearchResult> results) {
-        ObjectObjectHashMap<Term, TermStatistics> termStatistics = HppcMaps.newNoNullKeysMap();
-        ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics = HppcMaps.newNoNullKeysMap();
+        final Map<Term, TermStatistics> termStatistics = new HashMap<>();
+        final Map<String, CollectionStatistics> fieldStatistics = new HashMap<>();
         long aggMaxDoc = 0;
         for (DfsSearchResult lEntry : results) {
             final Term[] terms = lEntry.terms();
@@ -129,29 +132,25 @@ public AggregatedDfs aggregateDfs(Collection<DfsSearchResult> results) {
             }
 
             assert !lEntry.fieldStatistics().containsKey(null);
-            final Object[] keys = lEntry.fieldStatistics().keys;
-            final Object[] values = lEntry.fieldStatistics().values;
-            for (int i = 0; i < keys.length; i++) {
-                if (keys[i] != null) {
-                    String key = (String) keys[i];
-                    CollectionStatistics value = (CollectionStatistics) values[i];
-                    if (value == null) {
-                        continue;
-                    }
-                    assert key != null;
-                    CollectionStatistics existing = fieldStatistics.get(key);
-                    if (existing != null) {
-                        CollectionStatistics merged = new CollectionStatistics(
-                            key,
-                            existing.maxDoc() + value.maxDoc(),
-                            existing.docCount() + value.docCount(),
-                            existing.sumTotalTermFreq() + value.sumTotalTermFreq(),
-                            existing.sumDocFreq() + value.sumDocFreq()
-                        );
-                        fieldStatistics.put(key, merged);
-                    } else {
-                        fieldStatistics.put(key, value);
-                    }
+            for (var entry : lEntry.fieldStatistics().entrySet()) {
+                String key = entry.getKey();
+                CollectionStatistics value = entry.getValue();
+                if (value == null) {
+                    continue;
+                }
+                assert key != null;
+                CollectionStatistics existing = fieldStatistics.get(key);
+                if (existing != null) {
+                    CollectionStatistics merged = new CollectionStatistics(
+                        key,
+                        existing.maxDoc() + value.maxDoc(),
+                        existing.docCount() + value.docCount(),
+                        existing.sumTotalTermFreq() + value.sumTotalTermFreq(),
+                        existing.sumDocFreq() + value.sumDocFreq()
+                    );
+                    fieldStatistics.put(key, merged);
+                } else {
+                    fieldStatistics.put(key, value);
                 }
             }
             aggMaxDoc += lEntry.maxDoc();
@@ -230,14 +229,12 @@ static TopDocs mergeTopDocs(Collection<TopDocs> results, int topN, int from) {
         if (numShards == 1 && from == 0) { // only one shard and no pagination we can just return the topDocs as we got them.
             return topDocs;
         } else if (topDocs instanceof CollapseTopFieldDocs) {
-            CollapseTopFieldDocs firstTopDocs = (CollapseTopFieldDocs) topDocs;
-            final Sort sort = new Sort(firstTopDocs.fields);
             final CollapseTopFieldDocs[] shardTopDocs = results.toArray(new CollapseTopFieldDocs[numShards]);
+            final Sort sort = createSort(shardTopDocs);
             mergedTopDocs = CollapseTopFieldDocs.merge(sort, from, topN, shardTopDocs, false);
         } else if (topDocs instanceof TopFieldDocs) {
-            TopFieldDocs firstTopDocs = (TopFieldDocs) topDocs;
-            final Sort sort = new Sort(firstTopDocs.fields);
             final TopFieldDocs[] shardTopDocs = results.toArray(new TopFieldDocs[numShards]);
+            final Sort sort = createSort(shardTopDocs);
             mergedTopDocs = TopDocs.merge(sort, from, topN, shardTopDocs);
         } else {
             final TopDocs[] shardTopDocs = results.toArray(new TopDocs[numShards]);
@@ -272,12 +269,12 @@ public ScoreDoc[] getLastEmittedDocPerShard(ReducedQueryPhase reducedQueryPhase,
     /**
      * Builds an array, with potential null elements, with docs to load.
      */
-    public IntArrayList[] fillDocIdsToLoad(int numShards, ScoreDoc[] shardDocs) {
-        IntArrayList[] docIdsToLoad = new IntArrayList[numShards];
+    public List<Integer>[] fillDocIdsToLoad(int numShards, ScoreDoc[] shardDocs) {
+        final List<Integer>[] docIdsToLoad = (List<Integer>[]) new ArrayList<?>[numShards];
         for (ScoreDoc shardDoc : shardDocs) {
-            IntArrayList shardDocIdsToLoad = docIdsToLoad[shardDoc.shardIndex];
+            List<Integer> shardDocIdsToLoad = docIdsToLoad[shardDoc.shardIndex];
             if (shardDocIdsToLoad == null) {
-                shardDocIdsToLoad = docIdsToLoad[shardDoc.shardIndex] = new IntArrayList();
+                shardDocIdsToLoad = docIdsToLoad[shardDoc.shardIndex] = new ArrayList<>();
             }
             shardDocIdsToLoad.add(shardDoc.doc);
         }
@@ -579,12 +576,14 @@ private static void validateMergeSortValueFormats(Collection<? extends SearchPha
                 firstResult = false;
                 ulFormats = new boolean[formats.length];
                 for (int i = 0; i < formats.length; i++) {
-                    ulFormats[i] = formats[i] == DocValueFormat.UNSIGNED_LONG_SHIFTED ? true : false;
+                    ulFormats[i] = (formats[i] == DocValueFormat.UNSIGNED_LONG_SHIFTED || formats[i] == DocValueFormat.UNSIGNED_LONG)
+                        ? true
+                        : false;
                 }
             } else {
                 for (int i = 0; i < formats.length; i++) {
                     // if the format is unsigned_long in one shard, and something different in another shard
-                    if (ulFormats[i] ^ (formats[i] == DocValueFormat.UNSIGNED_LONG_SHIFTED)) {
+                    if (ulFormats[i] ^ (formats[i] == DocValueFormat.UNSIGNED_LONG_SHIFTED || formats[i] == DocValueFormat.UNSIGNED_LONG)) {
                         throw new IllegalArgumentException(
                             "Can't do sort across indices, as a field has [unsigned_long] type "
                                 + "in one index, and different type in another index!"
@@ -595,6 +594,48 @@ private static void validateMergeSortValueFormats(Collection<? extends SearchPha
         }
     }
 
+    /**
+     * Creates Sort object from topFieldsDocs fields.
+     * It is necessary to widen the SortField.Type to maximum byte size for merging sorted docs.
+     * Different indices might have different types. This will avoid user to do re-index of data
+     * in case of mapping field change for newly indexed data.
+     * This will support Int to Long and Float to Double.
+     * Earlier widening of type was taken care in IndexNumericFieldData, but since we now want to
+     * support sort optimization, we removed type widening there and taking care here during merging.
+     * More details here https://github.com/opensearch-project/OpenSearch/issues/6326
+     */
+    private static Sort createSort(TopFieldDocs[] topFieldDocs) {
+        final SortField[] firstTopDocFields = topFieldDocs[0].fields;
+        final SortField[] newFields = new SortField[firstTopDocFields.length];
+
+        for (int i = 0; i < firstTopDocFields.length; i++) {
+            final SortField delegate = firstTopDocFields[i];
+            final SortField.Type type = delegate instanceof SortedNumericSortField
+                ? ((SortedNumericSortField) delegate).getNumericType()
+                : delegate.getType();
+
+            if (SortedWiderNumericSortField.isTypeSupported(type) && isSortWideningRequired(topFieldDocs, i)) {
+                newFields[i] = new SortedWiderNumericSortField(delegate.getField(), type, delegate.getReverse());
+            } else {
+                newFields[i] = firstTopDocFields[i];
+            }
+        }
+        return new Sort(newFields);
+    }
+
+    /**
+     * It will compare respective SortField between shards to see if any shard results have different
+     * field mapping type, accordingly it will decide to widen the sort fields.
+     */
+    private static boolean isSortWideningRequired(TopFieldDocs[] topFieldDocs, int sortFieldindex) {
+        for (int i = 0; i < topFieldDocs.length - 1; i++) {
+            if (!topFieldDocs[i].fields[sortFieldindex].equals(topFieldDocs[i + 1].fields[sortFieldindex])) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /*
      * Returns the size of the requested top documents (from + size)
      */
@@ -608,6 +649,11 @@ static int getTopDocsSize(SearchRequest request) {
             : source.from());
     }
 
+    /**
+     * The reduced query phase
+     *
+     * @opensearch.internal
+     */
     public static final class ReducedQueryPhase {
         // the sum of all hits across all reduces shards
         final TotalHits totalHits;
@@ -683,7 +729,7 @@ public InternalSearchResponse buildResponse(SearchHits hits) {
     }
 
     InternalAggregation.ReduceContextBuilder getReduceContext(SearchRequest request) {
-        return requestToAggReduceContextBuilder.apply(request);
+        return requestToAggReduceContextBuilder.apply(request.source());
     }
 
     /**
@@ -709,6 +755,11 @@ QueryPhaseResultConsumer newSearchPhaseResults(
         );
     }
 
+    /**
+     * The top docs statistics
+     *
+     * @opensearch.internal
+     */
     static final class TopDocsStats {
         final int trackTotalHitsUpTo;
         long totalHits;
@@ -773,6 +824,11 @@ void add(TopDocsAndMaxScore topDocs, boolean timedOut, Boolean terminatedEarly)
         }
     }
 
+    /**
+     * Top docs that have been sorted
+     *
+     * @opensearch.internal
+     */
     static final class SortedTopDocs {
         static final SortedTopDocs EMPTY = new SortedTopDocs(EMPTY_DOCS, false, null, null, null);
         // the searches merged top docs
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhaseExecutionException.java b/server/src/main/java/org/opensearch/action/search/SearchPhaseExecutionException.java
index fbe6ef667f4f7..9ede6b4e3eb1b 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchPhaseExecutionException.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhaseExecutionException.java
@@ -32,20 +32,25 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ShardOperationFailedException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+/**
+ * Main exception thrown when there is an error in the search phase
+ *
+ * @opensearch.internal
+ */
 public class SearchPhaseExecutionException extends OpenSearchException {
     private final String phaseName;
     private final ShardSearchFailure[] shardFailures;
@@ -156,12 +161,21 @@ protected void metadataToXContent(XContentBuilder builder, Params params) throws
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         Throwable ex = ExceptionsHelper.unwrapCause(this);
         if (ex != this) {
-            generateThrowableXContent(builder, params, this);
+            OpenSearchException.generateThrowableXContent(builder, params, this);
         } else {
             // We don't have a cause when all shards failed, but we do have shards failures so we can "guess" a cause
             // (see {@link #getCause()}). Here, we use super.getCause() because we don't want the guessed exception to
             // be rendered twice (one in the "cause" field, one in "failed_shards")
-            innerToXContent(builder, params, this, getExceptionName(), getMessage(), getHeaders(), getMetadata(), super.getCause());
+            OpenSearchException.innerToXContent(
+                builder,
+                params,
+                this,
+                getExceptionName(),
+                getMessage(),
+                getHeaders(),
+                getMetadata(),
+                super.getCause()
+            );
         }
         return builder;
     }
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhaseName.java b/server/src/main/java/org/opensearch/action/search/SearchPhaseName.java
new file mode 100644
index 0000000000000..4c0fe3ac06326
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhaseName.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+/**
+ * Enum for different Search Phases in OpenSearch
+ * @opensearch.internal
+ */
+public enum SearchPhaseName {
+    DFS_PRE_QUERY("dfs_pre_query"),
+    QUERY("query"),
+    FETCH("fetch"),
+    DFS_QUERY("dfs_query"),
+    EXPAND("expand"),
+    CAN_MATCH("can_match");
+
+    private final String name;
+
+    SearchPhaseName(final String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/SearchPhaseResults.java b/server/src/main/java/org/opensearch/action/search/SearchPhaseResults.java
index 3fa520f1fb5d6..2e6068b1ecddc 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchPhaseResults.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchPhaseResults.java
@@ -39,8 +39,10 @@
 
 /**
  * This class acts as a basic result collection that can be extended to do on-the-fly reduction or result processing
+ *
+ * @opensearch.internal
  */
-abstract class SearchPhaseResults<Result extends SearchPhaseResult> {
+public abstract class SearchPhaseResults<Result extends SearchPhaseResult> {
     private final int numShards;
 
     SearchPhaseResults(int numShards) {
@@ -73,7 +75,13 @@ final int getNumShards() {
 
     void consumeShardFailure(int shardIndex) {}
 
-    AtomicArray<Result> getAtomicArray() {
+    /**
+     * Returns an {@link AtomicArray} of {@link Result}, which are nothing but the SearchPhaseResults
+     * for shards. The {@link Result} are of type {@link SearchPhaseResult}
+     *
+     * @return an {@link AtomicArray} of {@link Result}
+     */
+    public AtomicArray<Result> getAtomicArray() {
         throw new UnsupportedOperationException();
     }
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchProgressActionListener.java b/server/src/main/java/org/opensearch/action/search/SearchProgressActionListener.java
index 088aac6d71d30..320bebfa6a9f4 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchProgressActionListener.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchProgressActionListener.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * An {@link ActionListener} for search requests that allows to track progress of the {@link SearchAction}.
  * See {@link SearchProgressListener}.
+ *
+ * @opensearch.internal
  */
 public abstract class SearchProgressActionListener extends SearchProgressListener implements ActionListener<SearchResponse> {}
diff --git a/server/src/main/java/org/opensearch/action/search/SearchProgressListener.java b/server/src/main/java/org/opensearch/action/search/SearchProgressListener.java
index 78b1dd19dadaa..ffc64682cb07d 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchProgressListener.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchProgressListener.java
@@ -50,6 +50,8 @@
 
 /**
  * A listener that allows to track progress of the {@link SearchAction}.
+ *
+ * @opensearch.api
  */
 public abstract class SearchProgressListener {
     private static final Logger logger = LogManager.getLogger(SearchProgressListener.class);
diff --git a/server/src/main/java/org/opensearch/action/search/SearchQueryThenFetchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/SearchQueryThenFetchAsyncAction.java
index 93ce3cfd8c715..ca5ad087d3089 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchQueryThenFetchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchQueryThenFetchAsyncAction.java
@@ -34,9 +34,9 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.TopFieldDocs;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.GroupShardsIterator;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.AliasFilter;
@@ -50,6 +50,11 @@
 import java.util.concurrent.Executor;
 import java.util.function.BiFunction;
 
+/**
+ * Async transport action for query then fetch
+ *
+ * @opensearch.internal
+ */
 class SearchQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<SearchPhaseResult> {
 
     private final SearchPhaseController searchPhaseController;
@@ -76,10 +81,11 @@ class SearchQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<SearchPh
         final TransportSearchAction.SearchTimeProvider timeProvider,
         ClusterState clusterState,
         SearchTask task,
-        SearchResponse.Clusters clusters
+        SearchResponse.Clusters clusters,
+        SearchRequestOperationsListener searchRequestOperationsListener
     ) {
         super(
-            "query",
+            SearchPhaseName.QUERY.getName(),
             logger,
             searchTransportService,
             nodeIdToConnection,
@@ -95,7 +101,8 @@ class SearchQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<SearchPh
             task,
             resultConsumer,
             request.getMaxConcurrentShardRequests(),
-            clusters
+            clusters,
+            searchRequestOperationsListener
         );
         this.topDocsSize = SearchPhaseController.getTopDocsSize(request);
         this.trackTotalHitsUpTo = request.resolveTrackTotalHitsUpTo();
diff --git a/server/src/main/java/org/opensearch/action/search/SearchRequest.java b/server/src/main/java/org/opensearch/action/search/SearchRequest.java
index c4b97c35bc405..ce4d4acb6d6cc 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchRequest.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchRequest.java
@@ -39,16 +39,16 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.internal.SearchContext;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -69,6 +69,8 @@
  * @see org.opensearch.client.Requests#searchRequest(String...)
  * @see org.opensearch.client.Client#search(SearchRequest)
  * @see SearchResponse
+ *
+ * @opensearch.internal
  */
 public class SearchRequest extends ActionRequest implements IndicesRequest.Replaceable {
 
@@ -114,6 +116,8 @@ public class SearchRequest extends ActionRequest implements IndicesRequest.Repla
 
     private TimeValue cancelAfterTimeInterval;
 
+    private String pipeline;
+
     public SearchRequest() {
         this.localClusterAlias = null;
         this.absoluteStartMillis = DEFAULT_ABSOLUTE_START_MILLIS;
@@ -256,6 +260,9 @@ public SearchRequest(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(Version.V_1_1_0)) {
             cancelAfterTimeInterval = in.readOptionalTimeValue();
         }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            pipeline = in.readOptionalString();
+        }
     }
 
     @Override
@@ -293,6 +300,9 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(Version.V_1_1_0)) {
             out.writeOptionalTimeValue(cancelAfterTimeInterval);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeOptionalString(pipeline);
+        }
     }
 
     @Override
@@ -441,7 +451,8 @@ public SearchRequest routing(String... routings) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public SearchRequest preference(String preference) {
@@ -671,6 +682,15 @@ public TimeValue getCancelAfterTimeInterval() {
         return cancelAfterTimeInterval;
     }
 
+    public SearchRequest pipeline(String pipeline) {
+        this.pipeline = pipeline;
+        return this;
+    }
+
+    public String pipeline() {
+        return pipeline;
+    }
+
     @Override
     public SearchTask createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
         return new SearchTask(id, type, action, this::buildDescription, parentTaskId, headers, cancelAfterTimeInterval);
@@ -717,7 +737,8 @@ public boolean equals(Object o) {
             && Objects.equals(localClusterAlias, that.localClusterAlias)
             && absoluteStartMillis == that.absoluteStartMillis
             && ccsMinimizeRoundtrips == that.ccsMinimizeRoundtrips
-            && Objects.equals(cancelAfterTimeInterval, that.cancelAfterTimeInterval);
+            && Objects.equals(cancelAfterTimeInterval, that.cancelAfterTimeInterval)
+            && Objects.equals(pipeline, that.pipeline);
     }
 
     @Override
@@ -779,6 +800,8 @@ public String toString() {
             + source
             + ", cancelAfterTimeInterval="
             + cancelAfterTimeInterval
+            + ", pipeline="
+            + pipeline
             + "}";
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/search/SearchRequestBuilder.java b/server/src/main/java/org/opensearch/action/search/SearchRequestBuilder.java
index 6def33f82b7bd..861e1df0203d7 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchRequestBuilder.java
@@ -57,6 +57,8 @@
 
 /**
  * A search action request builder.
+ *
+ * @opensearch.internal
  */
 public class SearchRequestBuilder extends ActionRequestBuilder<SearchRequest, SearchResponse> {
 
@@ -149,7 +151,8 @@ public SearchRequestBuilder setRouting(String... routing) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public SearchRequestBuilder setPreference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/search/SearchRequestOperationsListener.java b/server/src/main/java/org/opensearch/action/search/SearchRequestOperationsListener.java
new file mode 100644
index 0000000000000..89d725b56bded
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/SearchRequestOperationsListener.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+
+import java.util.List;
+
+/**
+ * A listener for search, fetch and context events at the coordinator node level
+ *
+ * @opensearch.internal
+ */
+public interface SearchRequestOperationsListener {
+
+    void onPhaseStart(SearchPhaseContext context);
+
+    void onPhaseEnd(SearchPhaseContext context);
+
+    void onPhaseFailure(SearchPhaseContext context);
+
+    /**
+     * Holder of Composite Listeners
+     *
+     * @opensearch.internal
+     */
+
+    final class CompositeListener implements SearchRequestOperationsListener {
+        private final List<SearchRequestOperationsListener> listeners;
+        private final Logger logger;
+
+        public CompositeListener(List<SearchRequestOperationsListener> listeners, Logger logger) {
+            this.listeners = listeners;
+            this.logger = logger;
+        }
+
+        @Override
+        public void onPhaseStart(SearchPhaseContext context) {
+            for (SearchRequestOperationsListener listener : listeners) {
+                try {
+                    listener.onPhaseStart(context);
+                } catch (Exception e) {
+                    logger.warn(() -> new ParameterizedMessage("onPhaseStart listener [{}] failed", listener), e);
+                }
+            }
+        }
+
+        @Override
+        public void onPhaseEnd(SearchPhaseContext context) {
+            for (SearchRequestOperationsListener listener : listeners) {
+                try {
+                    listener.onPhaseEnd(context);
+                } catch (Exception e) {
+                    logger.warn(() -> new ParameterizedMessage("onPhaseEnd listener [{}] failed", listener), e);
+                }
+            }
+        }
+
+        @Override
+        public void onPhaseFailure(SearchPhaseContext context) {
+            for (SearchRequestOperationsListener listener : listeners) {
+                try {
+                    listener.onPhaseFailure(context);
+                } catch (Exception e) {
+                    logger.warn(() -> new ParameterizedMessage("onPhaseFailure listener [{}] failed", listener), e);
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/SearchRequestStats.java b/server/src/main/java/org/opensearch/action/search/SearchRequestStats.java
new file mode 100644
index 0000000000000..ad299c11b987d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/SearchRequestStats.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.common.metrics.MeanMetric;
+
+import java.util.EnumMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Request level search stats to track coordinator level node search latencies
+ *
+ * @opensearch.internal
+ */
+public final class SearchRequestStats implements SearchRequestOperationsListener {
+    Map<SearchPhaseName, StatsHolder> phaseStatsMap = new EnumMap<>(SearchPhaseName.class);
+
+    @Inject
+    public SearchRequestStats() {
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            phaseStatsMap.put(searchPhaseName, new StatsHolder());
+        }
+    }
+
+    public long getPhaseCurrent(SearchPhaseName searchPhaseName) {
+        return phaseStatsMap.get(searchPhaseName).current.count();
+    }
+
+    public long getPhaseTotal(SearchPhaseName searchPhaseName) {
+        return phaseStatsMap.get(searchPhaseName).total.count();
+    }
+
+    public long getPhaseMetric(SearchPhaseName searchPhaseName) {
+        return phaseStatsMap.get(searchPhaseName).timing.sum();
+    }
+
+    @Override
+    public void onPhaseStart(SearchPhaseContext context) {
+        phaseStatsMap.get(context.getCurrentPhase().getSearchPhaseName()).current.inc();
+    }
+
+    @Override
+    public void onPhaseEnd(SearchPhaseContext context) {
+        StatsHolder phaseStats = phaseStatsMap.get(context.getCurrentPhase().getSearchPhaseName());
+        phaseStats.current.dec();
+        phaseStats.total.inc();
+        phaseStats.timing.inc(TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - context.getCurrentPhase().getStartTimeInNanos()));
+    }
+
+    @Override
+    public void onPhaseFailure(SearchPhaseContext context) {
+        phaseStatsMap.get(context.getCurrentPhase().getSearchPhaseName()).current.dec();
+    }
+
+    /**
+     * Holder of statistics values
+     *
+     * @opensearch.internal
+     */
+
+    public static final class StatsHolder {
+        CounterMetric current = new CounterMetric();
+        CounterMetric total = new CounterMetric();
+        MeanMetric timing = new MeanMetric();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/SearchResponse.java b/server/src/main/java/org/opensearch/action/search/SearchResponse.java
index e1175dc079ee0..3eb698f2c140d 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchResponse.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchResponse.java
@@ -34,21 +34,25 @@
 
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.rest.action.RestActions;
+import org.opensearch.search.GenericSearchExtBuilder;
+import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.Aggregations;
@@ -65,10 +69,13 @@
 import java.util.Objects;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.action.search.SearchResponseSections.EXT_FIELD;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A response of a search request.
+ *
+ * @opensearch.internal
  */
 public class SearchResponse extends ActionResponse implements StatusToXContentObject {
 
@@ -78,6 +85,7 @@ public class SearchResponse extends ActionResponse implements StatusToXContentOb
     private static final ParseField TIMED_OUT = new ParseField("timed_out");
     private static final ParseField TERMINATED_EARLY = new ParseField("terminated_early");
     private static final ParseField NUM_REDUCE_PHASES = new ParseField("num_reduce_phases");
+    private static final ParseField EXT = new ParseField("ext");
 
     private final SearchResponseSections internalResponse;
     private final String scrollId;
@@ -89,6 +97,8 @@ public class SearchResponse extends ActionResponse implements StatusToXContentOb
     private final Clusters clusters;
     private final long tookInMillis;
 
+    private List<SearchExtBuilder> searchExtBuilders = new ArrayList<>();
+
     public SearchResponse(StreamInput in) throws IOException {
         super(in);
         internalResponse = new InternalSearchResponse(in);
@@ -314,6 +324,7 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
         );
         clusters.toXContent(builder, params);
         internalResponse.toXContent(builder, params);
+
         return builder;
     }
 
@@ -341,6 +352,7 @@ public static SearchResponse innerFromXContent(XContentParser parser) throws IOE
         String searchContextId = null;
         List<ShardSearchFailure> failures = new ArrayList<>();
         Clusters clusters = Clusters.EMPTY;
+        List<SearchExtBuilder> extBuilders = new ArrayList<>();
         for (Token token = parser.nextToken(); token != Token.END_OBJECT; token = parser.nextToken()) {
             if (token == Token.FIELD_NAME) {
                 currentFieldName = parser.currentName();
@@ -419,6 +431,33 @@ public static SearchResponse innerFromXContent(XContentParser parser) throws IOE
                         }
                     }
                     clusters = new Clusters(total, successful, skipped);
+                } else if (EXT_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
+                    String extSectionName = null;
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            extSectionName = parser.currentName();
+                        } else {
+                            SearchExtBuilder searchExtBuilder;
+                            try {
+                                searchExtBuilder = parser.namedObject(SearchExtBuilder.class, extSectionName, null);
+                                if (!searchExtBuilder.getWriteableName().equals(extSectionName)) {
+                                    throw new IllegalStateException(
+                                        "The parsed ["
+                                            + searchExtBuilder.getClass().getName()
+                                            + "] object has a "
+                                            + "different writeable name compared to the name of the section that it was parsed from: found ["
+                                            + searchExtBuilder.getWriteableName()
+                                            + "] expected ["
+                                            + extSectionName
+                                            + "]"
+                                    );
+                                }
+                            } catch (XContentParseException e) {
+                                searchExtBuilder = GenericSearchExtBuilder.fromXContent(parser);
+                            }
+                            extBuilders.add(searchExtBuilder);
+                        }
+                    }
                 } else {
                     parser.skipChildren();
                 }
@@ -431,7 +470,8 @@ public static SearchResponse innerFromXContent(XContentParser parser) throws IOE
             timedOut,
             terminatedEarly,
             profile,
-            numReducePhases
+            numReducePhases,
+            extBuilders
         );
         return new SearchResponse(
             searchResponseSections,
@@ -467,12 +507,18 @@ public void writeTo(StreamOutput out) throws IOException {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    public void addSearchExtBuilder(SearchExtBuilder searchExtBuilder) {
+        this.searchExtBuilders.add(searchExtBuilder);
     }
 
     /**
      * Holds info about the clusters that the search was executed on: how many in total, how many of them were successful
      * and how many of them were skipped.
+     *
+     * @opensearch.internal
      */
     public static class Clusters implements ToXContentFragment, Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchResponseMerger.java b/server/src/main/java/org/opensearch/action/search/SearchResponseMerger.java
index 528c0693fbcd8..f90e98106f93f 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchResponseMerger.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchResponseMerger.java
@@ -41,7 +41,7 @@
 import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.SearchShardTarget;
@@ -79,6 +79,8 @@
  * - scroll requests are not supported
  * - field collapsing is supported, but whenever inner_hits are requested, they will be retrieved by each cluster locally after the fetch
  * phase, through the {@link ExpandSearchPhase}. Such inner_hits are not merged together as part of hits reduction.
+ *
+ * @opensearch.internal
  */
 // TODO it may make sense to integrate the remote clusters responses as a shard response in the initial search phase and ignore hits coming
 // from the remote clusters in the fetch phase. This would be identical to the removed QueryAndFetch strategy except that only the remote
@@ -408,6 +410,11 @@ private static SearchHits topDocsToSearchHits(TopDocs topDocs, SearchPhaseContro
         );
     }
 
+    /**
+     * Holds a field search hit and doc
+     *
+     * @opensearch.internal
+     */
     private static final class FieldDocAndSearchHit extends FieldDoc {
         private final SearchHit searchHit;
 
@@ -424,6 +431,8 @@ private static final class FieldDocAndSearchHit extends FieldDoc {
      * (see TopDocs#tieBreakLessThan line 86). Generally, indices with same names on different clusters have different index uuids which
      * make their ShardIds different, which is not the case if the index is really the same one from the same cluster, in which case we
      * need to look at the cluster alias and make sure to assign a different shardIndex based on that.
+     *
+     * @opensearch.internal
      */
     private static final class ShardIdAndClusterAlias implements Comparable<ShardIdAndClusterAlias> {
         private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchResponseSections.java b/server/src/main/java/org/opensearch/action/search/SearchResponseSections.java
index e146859bb295f..2e447abd125c5 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchResponseSections.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchResponseSections.java
@@ -32,9 +32,11 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.profile.ProfileShardResult;
@@ -42,8 +44,11 @@
 import org.opensearch.search.suggest.Suggest;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Base class that holds the various sections which a search response is
@@ -52,9 +57,13 @@
  * The reason why this class exists is that the high level REST client uses its own classes
  * to parse aggregations into, which are not serializable. This is the common part that can be
  * shared between core and client.
+ *
+ * @opensearch.internal
  */
 public class SearchResponseSections implements ToXContentFragment {
 
+    public static final ParseField EXT_FIELD = new ParseField("ext");
+
     protected final SearchHits hits;
     protected final Aggregations aggregations;
     protected final Suggest suggest;
@@ -62,6 +71,7 @@ public class SearchResponseSections implements ToXContentFragment {
     protected final boolean timedOut;
     protected final Boolean terminatedEarly;
     protected final int numReducePhases;
+    protected final List<SearchExtBuilder> searchExtBuilders = new ArrayList<>();
 
     public SearchResponseSections(
         SearchHits hits,
@@ -71,6 +81,19 @@ public SearchResponseSections(
         Boolean terminatedEarly,
         SearchProfileShardResults profileResults,
         int numReducePhases
+    ) {
+        this(hits, aggregations, suggest, timedOut, terminatedEarly, profileResults, numReducePhases, Collections.emptyList());
+    }
+
+    public SearchResponseSections(
+        SearchHits hits,
+        Aggregations aggregations,
+        Suggest suggest,
+        boolean timedOut,
+        Boolean terminatedEarly,
+        SearchProfileShardResults profileResults,
+        int numReducePhases,
+        List<SearchExtBuilder> searchExtBuilders
     ) {
         this.hits = hits;
         this.aggregations = aggregations;
@@ -79,6 +102,7 @@ public SearchResponseSections(
         this.timedOut = timedOut;
         this.terminatedEarly = terminatedEarly;
         this.numReducePhases = numReducePhases;
+        this.searchExtBuilders.addAll(Objects.requireNonNull(searchExtBuilders, "searchExtBuilders must not be null"));
     }
 
     public final boolean timedOut() {
@@ -133,9 +157,20 @@ public final XContentBuilder toXContent(XContentBuilder builder, Params params)
         if (profileResults != null) {
             profileResults.toXContent(builder, params);
         }
+        if (!searchExtBuilders.isEmpty()) {
+            builder.startObject(EXT_FIELD.getPreferredName());
+            for (SearchExtBuilder searchExtBuilder : searchExtBuilders) {
+                searchExtBuilder.toXContent(builder, params);
+            }
+            builder.endObject();
+        }
         return builder;
     }
 
+    public List<SearchExtBuilder> getSearchExtBuilders() {
+        return Collections.unmodifiableList(this.searchExtBuilders);
+    }
+
     protected void writeTo(StreamOutput out) throws IOException {
         throw new UnsupportedOperationException();
     }
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollAction.java b/server/src/main/java/org/opensearch/action/search/SearchScrollAction.java
index 4aec3d39e6f47..1f466d35f0ac2 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for a search scroll
+ *
+ * @opensearch.internal
+ */
 public class SearchScrollAction extends ActionType<SearchResponse> {
 
     public static final SearchScrollAction INSTANCE = new SearchScrollAction();
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollAsyncAction.java b/server/src/main/java/org/opensearch/action/search/SearchScrollAsyncAction.java
index f98a75d37988c..51d9a34937f79 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollAsyncAction.java
@@ -34,12 +34,12 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
@@ -62,6 +62,8 @@
  * Abstract base class for scroll execution modes. This class encapsulates the basic logic to
  * fan out to nodes and execute the query part of the scroll request. Subclasses can for instance
  * run separate fetch phases etc.
+ *
+ * @opensearch.internal
  */
 abstract class SearchScrollAsyncAction<T extends SearchPhaseResult> implements Runnable {
     protected final Logger logger;
@@ -264,7 +266,7 @@ protected SearchPhase sendResponsePhase(
         SearchPhaseController.ReducedQueryPhase queryPhase,
         final AtomicArray<? extends SearchPhaseResult> fetchResults
     ) {
-        return new SearchPhase("fetch") {
+        return new SearchPhase(SearchPhaseName.FETCH.getName()) {
             @Override
             public void run() throws IOException {
                 sendResponse(queryPhase, fetchResults);
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollQueryAndFetchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/SearchScrollQueryAndFetchAsyncAction.java
index 59ce2567bdf18..f7737fe59a975 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollQueryAndFetchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollQueryAndFetchAsyncAction.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.search;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.fetch.QueryFetchSearchResult;
 import org.opensearch.search.fetch.ScrollQueryFetchSearchResult;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
@@ -44,6 +44,11 @@
 
 import java.util.function.BiFunction;
 
+/**
+ * Async action for a search scroll query then fetch
+ *
+ * @opensearch.internal
+ */
 final class SearchScrollQueryAndFetchAsyncAction extends SearchScrollAsyncAction<ScrollQueryFetchSearchResult> {
 
     private final SearchTask task;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollQueryThenFetchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/SearchScrollQueryThenFetchAsyncAction.java
index effe5afd0cad6..87ba32016370f 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollQueryThenFetchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollQueryThenFetchAsyncAction.java
@@ -32,14 +32,13 @@
 
 package org.opensearch.action.search;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.ScoreDoc;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.fetch.FetchSearchResult;
 import org.opensearch.search.fetch.ShardFetchRequest;
@@ -48,8 +47,14 @@
 import org.opensearch.search.query.ScrollQuerySearchResult;
 import org.opensearch.transport.Transport;
 
+import java.util.List;
 import java.util.function.BiFunction;
 
+/**
+ * async action for a search scroll query then fetch
+ *
+ * @opensearch.internal
+ */
 final class SearchScrollQueryThenFetchAsyncAction extends SearchScrollAsyncAction<ScrollQuerySearchResult> {
 
     private final SearchTask task;
@@ -87,7 +92,7 @@ protected void executeInitialPhase(
 
     @Override
     protected SearchPhase moveToNextPhase(BiFunction<String, String, DiscoveryNode> clusterNodeLookup) {
-        return new SearchPhase("fetch") {
+        return new SearchPhase(SearchPhaseName.FETCH.getName()) {
             @Override
             public void run() {
                 final SearchPhaseController.ReducedQueryPhase reducedQueryPhase = searchPhaseController.reducedScrollQueryPhase(
@@ -99,7 +104,7 @@ public void run() {
                     return;
                 }
 
-                final IntArrayList[] docIdsToLoad = searchPhaseController.fillDocIdsToLoad(queryResults.length(), scoreDocs);
+                final List<Integer>[] docIdsToLoad = searchPhaseController.fillDocIdsToLoad(queryResults.length(), scoreDocs);
                 final ScoreDoc[] lastEmittedDocPerShard = searchPhaseController.getLastEmittedDocPerShard(
                     reducedQueryPhase,
                     queryResults.length()
@@ -107,7 +112,7 @@ public void run() {
                 final CountDown counter = new CountDown(docIdsToLoad.length);
                 for (int i = 0; i < docIdsToLoad.length; i++) {
                     final int index = i;
-                    final IntArrayList docIds = docIdsToLoad[index];
+                    final List<Integer> docIds = docIdsToLoad[index];
                     if (docIds != null) {
                         final QuerySearchResult querySearchResult = queryResults.get(index);
                         ScoreDoc lastEmittedDoc = lastEmittedDocPerShard[index];
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollRequest.java b/server/src/main/java/org/opensearch/action/search/SearchScrollRequest.java
index 828228e869831..cda00811e5500 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollRequest.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollRequest.java
@@ -34,15 +34,15 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.Scroll;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Map;
@@ -50,6 +50,11 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport request for a search scroll
+ *
+ * @opensearch.internal
+ */
 public class SearchScrollRequest extends ActionRequest implements ToXContentObject {
 
     private String scrollId;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchScrollRequestBuilder.java b/server/src/main/java/org/opensearch/action/search/SearchScrollRequestBuilder.java
index 79bd952333de2..638c595216631 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchScrollRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchScrollRequestBuilder.java
@@ -39,6 +39,8 @@
 
 /**
  * A search scroll action request builder.
+ *
+ * @opensearch.internal
  */
 public class SearchScrollRequestBuilder extends ActionRequestBuilder<SearchScrollRequest, SearchResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/search/SearchShard.java b/server/src/main/java/org/opensearch/action/search/SearchShard.java
index 110209e3e9af0..478788277bb19 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchShard.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchShard.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.search;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Comparator;
 import java.util.Objects;
@@ -41,6 +41,8 @@
 /**
  * A class that encapsulates the {@link ShardId} and the cluster alias
  * of a shard used during the search action.
+ *
+ * @opensearch.internal
  */
 public final class SearchShard implements Comparable<SearchShard> {
     @Nullable
diff --git a/server/src/main/java/org/opensearch/action/search/SearchShardIterator.java b/server/src/main/java/org/opensearch/action/search/SearchShardIterator.java
index 1ae0d8f78aa9c..fbd85a3fc0b8f 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchShardIterator.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchShardIterator.java
@@ -39,7 +39,7 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.Countable;
 import org.opensearch.common.util.PlainIterator;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.ShardSearchContextId;
 
@@ -53,6 +53,8 @@
  * of the search request (useful especially with cross-cluster search, as each cluster has its own set of original indices) as well as
  * the cluster alias.
  * @see OriginalIndices
+ *
+ * @opensearch.internal
  */
 public final class SearchShardIterator implements Comparable<SearchShardIterator>, Countable {
 
@@ -117,7 +119,7 @@ public String getClusterAlias() {
         return clusterAlias;
     }
 
-    SearchShardTarget nextOrNull() {
+    public SearchShardTarget nextOrNull() {
         final String nodeId = targetNodesIterator.nextOrNull();
         if (nodeId != null) {
             return new SearchShardTarget(nodeId, shardId, clusterAlias, originalIndices);
diff --git a/server/src/main/java/org/opensearch/action/search/SearchShardTask.java b/server/src/main/java/org/opensearch/action/search/SearchShardTask.java
index 2e506c6fe181b..54faaf363cb70 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchShardTask.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchShardTask.java
@@ -32,21 +32,50 @@
 
 package org.opensearch.action.search;
 
+import org.opensearch.common.MemoizedSupplier;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.fetch.ShardFetchSearchRequest;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.tasks.CancellableTask;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.tasks.SearchBackpressureTask;
 
 import java.util.Map;
+import java.util.function.Supplier;
 
 /**
  * Task storing information about a currently running search shard request.
  * See {@link ShardSearchRequest}, {@link ShardFetchSearchRequest}, ...
+ *
+ * @opensearch.internal
  */
-public class SearchShardTask extends CancellableTask {
+public class SearchShardTask extends CancellableTask implements SearchBackpressureTask {
+    // generating metadata in a lazy way since source can be quite big
+    private final MemoizedSupplier<String> metadataSupplier;
 
     public SearchShardTask(long id, String type, String action, String description, TaskId parentTaskId, Map<String, String> headers) {
+        this(id, type, action, description, parentTaskId, headers, () -> "");
+    }
+
+    public SearchShardTask(
+        long id,
+        String type,
+        String action,
+        String description,
+        TaskId parentTaskId,
+        Map<String, String> headers,
+        Supplier<String> metadataSupplier
+    ) {
         super(id, type, action, description, parentTaskId, headers);
+        this.metadataSupplier = new MemoizedSupplier<>(metadataSupplier);
+    }
+
+    public String getTaskMetadata() {
+        return metadataSupplier.get();
+    }
+
+    @Override
+    public boolean supportsResourceTracking() {
+        return true;
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/search/SearchTask.java b/server/src/main/java/org/opensearch/action/search/SearchTask.java
index 7f80f7836be6c..20370b7b17a07 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchTask.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchTask.java
@@ -33,8 +33,9 @@
 package org.opensearch.action.search;
 
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.CancellableTask;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.tasks.SearchBackpressureTask;
 
 import java.util.Map;
 import java.util.function.Supplier;
@@ -43,8 +44,10 @@
 
 /**
  * Task storing information about a currently running {@link SearchRequest}.
+ *
+ * @opensearch.internal
  */
-public class SearchTask extends CancellableTask {
+public class SearchTask extends CancellableTask implements SearchBackpressureTask {
     // generating description in a lazy way since source can be quite big
     private final Supplier<String> descriptionSupplier;
     private SearchProgressListener progressListener = SearchProgressListener.NOOP;
@@ -78,6 +81,11 @@ public final String getDescription() {
         return descriptionSupplier.get();
     }
 
+    @Override
+    public boolean supportsResourceTracking() {
+        return true;
+    }
+
     /**
      * Attach a {@link SearchProgressListener} to this task.
      */
diff --git a/server/src/main/java/org/opensearch/action/search/SearchTransportService.java b/server/src/main/java/org/opensearch/action/search/SearchTransportService.java
index 121de6d1c80da..a25ff0a0201a1 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchTransportService.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchTransportService.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.OriginalIndices;
@@ -42,10 +41,12 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.dfs.DfsSearchResult;
@@ -67,11 +68,12 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.BiFunction;
@@ -79,12 +81,16 @@
 /**
  * An encapsulation of {@link org.opensearch.search.SearchService} operations exposed through
  * transport.
+ *
+ * @opensearch.internal
  */
 public class SearchTransportService {
 
     public static final String FREE_CONTEXT_SCROLL_ACTION_NAME = "indices:data/read/search[free_context/scroll]";
     public static final String FREE_CONTEXT_ACTION_NAME = "indices:data/read/search[free_context]";
     public static final String CLEAR_SCROLL_CONTEXTS_ACTION_NAME = "indices:data/read/search[clear_scroll_contexts]";
+    public static final String FREE_PIT_CONTEXT_ACTION_NAME = "indices:data/read/search[free_context/pit]";
+    public static final String FREE_ALL_PIT_CONTEXTS_ACTION_NAME = "indices:data/read/search[free_pit_contexts]";
     public static final String DFS_ACTION_NAME = "indices:data/read/search[phase/dfs]";
     public static final String QUERY_ACTION_NAME = "indices:data/read/search[phase/query]";
     public static final String QUERY_ID_ACTION_NAME = "indices:data/read/search[phase/query/id]";
@@ -93,6 +99,8 @@ public class SearchTransportService {
     public static final String FETCH_ID_SCROLL_ACTION_NAME = "indices:data/read/search[phase/fetch/id/scroll]";
     public static final String FETCH_ID_ACTION_NAME = "indices:data/read/search[phase/fetch/id]";
     public static final String QUERY_CAN_MATCH_NAME = "indices:data/read/search[can_match]";
+    public static final String CREATE_READER_CONTEXT_ACTION_NAME = "indices:data/read/search[create_context]";
+    public static final String UPDATE_READER_CONTEXT_ACTION_NAME = "indices:data/read/search[update_context]";
 
     private final TransportService transportService;
     private final BiFunction<Transport.Connection, SearchActionListener, ActionListener> responseWrapper;
@@ -140,6 +148,36 @@ public void sendFreeContext(
         );
     }
 
+    public void updatePitContext(
+        Transport.Connection connection,
+        UpdatePitContextRequest request,
+        ActionListener<UpdatePitContextResponse> actionListener
+    ) {
+        transportService.sendRequest(
+            connection,
+            UPDATE_READER_CONTEXT_ACTION_NAME,
+            request,
+            TransportRequestOptions.EMPTY,
+            new ActionListenerResponseHandler<>(actionListener, UpdatePitContextResponse::new)
+        );
+    }
+
+    public void createPitContext(
+        Transport.Connection connection,
+        TransportCreatePitAction.CreateReaderContextRequest request,
+        SearchTask task,
+        ActionListener<TransportCreatePitAction.CreateReaderContextResponse> actionListener
+    ) {
+        transportService.sendChildRequest(
+            connection,
+            CREATE_READER_CONTEXT_ACTION_NAME,
+            request,
+            task,
+            TransportRequestOptions.EMPTY,
+            new ActionListenerResponseHandler<>(actionListener, TransportCreatePitAction.CreateReaderContextResponse::new)
+        );
+    }
+
     public void sendCanMatch(
         Transport.Connection connection,
         final ShardSearchRequest request,
@@ -166,6 +204,20 @@ public void sendClearAllScrollContexts(Transport.Connection connection, final Ac
         );
     }
 
+    public void sendFreePITContexts(
+        Transport.Connection connection,
+        List<PitSearchContextIdForNode> contextIds,
+        ActionListener<DeletePitResponse> listener
+    ) {
+        transportService.sendRequest(
+            connection,
+            FREE_PIT_CONTEXT_ACTION_NAME,
+            new PitFreeContextsRequest(contextIds),
+            TransportRequestOptions.EMPTY,
+            new ActionListenerResponseHandler<>(listener, DeletePitResponse::new)
+        );
+    }
+
     public void sendExecuteDfs(
         Transport.Connection connection,
         final ShardSearchRequest request,
@@ -307,6 +359,11 @@ public Map<String, Long> getPendingSearchRequests() {
         return new HashMap<>(clientConnections);
     }
 
+    /**
+     * A scroll free context request
+     *
+     * @opensearch.internal
+     */
     static class ScrollFreeContextRequest extends TransportRequest {
         private ShardSearchContextId contextId;
 
@@ -331,6 +388,48 @@ public ShardSearchContextId id() {
 
     }
 
+    /**
+     * Request to free the PIT context based on id
+     */
+    static class PitFreeContextsRequest extends TransportRequest {
+        private List<PitSearchContextIdForNode> contextIds;
+
+        PitFreeContextsRequest(List<PitSearchContextIdForNode> contextIds) {
+            this.contextIds = new ArrayList<>();
+            this.contextIds.addAll(contextIds);
+        }
+
+        PitFreeContextsRequest(StreamInput in) throws IOException {
+            super(in);
+            int size = in.readVInt();
+            if (size > 0) {
+                this.contextIds = new ArrayList<>();
+                for (int i = 0; i < size; i++) {
+                    PitSearchContextIdForNode contextId = new PitSearchContextIdForNode(in);
+                    contextIds.add(contextId);
+                }
+            }
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeVInt(contextIds.size());
+            for (PitSearchContextIdForNode contextId : contextIds) {
+                contextId.writeTo(out);
+            }
+        }
+
+        public List<PitSearchContextIdForNode> getContextIds() {
+            return this.contextIds;
+        }
+    }
+
+    /**
+     * A search free context request
+     *
+     * @opensearch.internal
+     */
     static class SearchFreeContextRequest extends ScrollFreeContextRequest implements IndicesRequest {
         private OriginalIndices originalIndices;
 
@@ -368,6 +467,11 @@ public IndicesOptions indicesOptions() {
 
     }
 
+    /**
+     * A search free context response
+     *
+     * @opensearch.internal
+     */
     public static class SearchFreeContextResponse extends TransportResponse {
 
         private boolean freed;
@@ -405,6 +509,17 @@ public static void registerRequestHandler(TransportService transportService, Sea
             }
         );
         TransportActionProxy.registerProxyAction(transportService, FREE_CONTEXT_SCROLL_ACTION_NAME, SearchFreeContextResponse::new);
+
+        transportService.registerRequestHandler(
+            FREE_PIT_CONTEXT_ACTION_NAME,
+            ThreadPool.Names.SAME,
+            PitFreeContextsRequest::new,
+            (request, channel, task) -> {
+                channel.sendResponse(searchService.freeReaderContextsIfFound(request.getContextIds()));
+            }
+        );
+        TransportActionProxy.registerProxyAction(transportService, FREE_PIT_CONTEXT_ACTION_NAME, DeletePitResponse::new);
+
         transportService.registerRequestHandler(
             FREE_CONTEXT_ACTION_NAME,
             ThreadPool.Names.SAME,
@@ -545,6 +660,48 @@ public static void registerRequestHandler(TransportService transportService, Sea
             }
         );
         TransportActionProxy.registerProxyAction(transportService, QUERY_CAN_MATCH_NAME, SearchService.CanMatchResponse::new);
+        transportService.registerRequestHandler(
+            CREATE_READER_CONTEXT_ACTION_NAME,
+            ThreadPool.Names.SAME,
+            TransportCreatePitAction.CreateReaderContextRequest::new,
+            (request, channel, task) -> {
+                ChannelActionListener<
+                    TransportCreatePitAction.CreateReaderContextResponse,
+                    TransportCreatePitAction.CreateReaderContextRequest> listener = new ChannelActionListener<>(
+                        channel,
+                        CREATE_READER_CONTEXT_ACTION_NAME,
+                        request
+                    );
+                searchService.createPitReaderContext(
+                    request.getShardId(),
+                    request.getKeepAlive(),
+                    ActionListener.wrap(
+                        r -> listener.onResponse(new TransportCreatePitAction.CreateReaderContextResponse(r)),
+                        listener::onFailure
+                    )
+                );
+            }
+        );
+        TransportActionProxy.registerProxyAction(
+            transportService,
+            CREATE_READER_CONTEXT_ACTION_NAME,
+            TransportCreatePitAction.CreateReaderContextResponse::new
+        );
+
+        transportService.registerRequestHandler(
+            UPDATE_READER_CONTEXT_ACTION_NAME,
+            ThreadPool.Names.SAME,
+            UpdatePitContextRequest::new,
+            (request, channel, task) -> {
+                ChannelActionListener<UpdatePitContextResponse, UpdatePitContextRequest> listener = new ChannelActionListener<>(
+                    channel,
+                    UPDATE_READER_CONTEXT_ACTION_NAME,
+                    request
+                );
+                searchService.updatePitIdAndKeepAlive(request, listener);
+            }
+        );
+        TransportActionProxy.registerProxyAction(transportService, UPDATE_READER_CONTEXT_ACTION_NAME, UpdatePitContextResponse::new);
     }
 
     /**
@@ -562,6 +719,11 @@ public Transport.Connection getConnection(@Nullable String clusterAlias, Discove
         }
     }
 
+    /**
+     * A handler that counts connections
+     *
+     * @opensearch.internal
+     */
     final class ConnectionCountingHandler<Response extends TransportResponse> extends ActionListenerResponseHandler<Response> {
         private final Map<String, Long> clientConnections;
         private final String nodeId;
diff --git a/server/src/main/java/org/opensearch/action/search/SearchType.java b/server/src/main/java/org/opensearch/action/search/SearchType.java
index ea50ea4b93491..cb86c0d6c1b4a 100644
--- a/server/src/main/java/org/opensearch/action/search/SearchType.java
+++ b/server/src/main/java/org/opensearch/action/search/SearchType.java
@@ -35,7 +35,7 @@
 /**
  * Search type represent the manner at which the search operation is executed.
  *
- *
+ * @opensearch.internal
  */
 public enum SearchType {
     /**
diff --git a/server/src/main/java/org/opensearch/action/search/SearchUtils.java b/server/src/main/java/org/opensearch/action/search/SearchUtils.java
new file mode 100644
index 0000000000000..ad4ac8f2a9eec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/SearchUtils.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.StepListener;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.transport.RemoteClusterService;
+
+import java.util.Set;
+import java.util.function.BiFunction;
+
+/**
+ * Helper class for common search functions
+ */
+public class SearchUtils {
+
+    public SearchUtils() {}
+
+    /**
+     * Get connection lookup listener for list of clusters passed
+     */
+    public static ActionListener<BiFunction<String, String, DiscoveryNode>> getConnectionLookupListener(
+        RemoteClusterService remoteClusterService,
+        ClusterState state,
+        Set<String> clusters
+    ) {
+        final StepListener<BiFunction<String, String, DiscoveryNode>> lookupListener = new StepListener<>();
+
+        if (clusters.isEmpty()) {
+            lookupListener.onResponse((cluster, nodeId) -> state.getNodes().get(nodeId));
+        } else {
+            remoteClusterService.collectNodes(clusters, lookupListener);
+        }
+        return lookupListener;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/ShardSearchFailure.java b/server/src/main/java/org/opensearch/action/search/ShardSearchFailure.java
index 228eac89f48d5..4d3f9b71a919c 100644
--- a/server/src/main/java/org/opensearch/action/search/ShardSearchFailure.java
+++ b/server/src/main/java/org/opensearch/action/search/ShardSearchFailure.java
@@ -35,26 +35,28 @@
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.transport.RemoteClusterAware;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Represents a failure to search on a specific shard.
+ *
+ * @opensearch.internal
  */
 public class ShardSearchFailure extends ShardOperationFailedException {
 
@@ -83,17 +85,20 @@ public ShardSearchFailure(Exception e) {
     }
 
     public ShardSearchFailure(Exception e, @Nullable SearchShardTarget shardTarget) {
+        this(e, ExceptionsHelper.unwrapCause(e), shardTarget);
+    }
+
+    private ShardSearchFailure(final Exception e, final Throwable unwrappedCause, @Nullable SearchShardTarget shardTarget) {
         super(
             shardTarget == null ? null : shardTarget.getFullyQualifiedIndexName(),
             shardTarget == null ? -1 : shardTarget.getShardId().getId(),
             ExceptionsHelper.detailedMessage(e),
-            ExceptionsHelper.status(ExceptionsHelper.unwrapCause(e)),
-            ExceptionsHelper.unwrapCause(e)
+            ExceptionsHelper.status(unwrappedCause),
+            unwrappedCause
         );
 
-        final Throwable actual = ExceptionsHelper.unwrapCause(e);
-        if (actual instanceof SearchException) {
-            this.shardTarget = ((SearchException) actual).shard();
+        if (unwrappedCause instanceof SearchException) {
+            this.shardTarget = ((SearchException) unwrappedCause).shard();
         } else if (shardTarget != null) {
             this.shardTarget = shardTarget;
         }
diff --git a/server/src/main/java/org/opensearch/action/search/TransportClearScrollAction.java b/server/src/main/java/org/opensearch/action/search/TransportClearScrollAction.java
index 1158dbe2b06e8..e67005eb1fb87 100644
--- a/server/src/main/java/org/opensearch/action/search/TransportClearScrollAction.java
+++ b/server/src/main/java/org/opensearch/action/search/TransportClearScrollAction.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Perform transport action to clear a search scroll
+ *
+ * @opensearch.internal
+ */
 public class TransportClearScrollAction extends HandledTransportAction<ClearScrollRequest, ClearScrollResponse> {
 
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/search/TransportCreatePitAction.java b/server/src/main/java/org/opensearch/action/search/TransportCreatePitAction.java
new file mode 100644
index 0000000000000..baa113997f243
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/TransportCreatePitAction.java
@@ -0,0 +1,133 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.StepListener;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.tasks.Task;
+import org.opensearch.transport.TransportRequest;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * Transport action for creating PIT reader context
+ */
+public class TransportCreatePitAction extends HandledTransportAction<CreatePitRequest, CreatePitResponse> {
+
+    public static final String CREATE_PIT_ACTION = "create_pit";
+    private final TransportService transportService;
+    private final SearchTransportService searchTransportService;
+    private final ClusterService clusterService;
+    private final TransportSearchAction transportSearchAction;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final CreatePitController createPitController;
+
+    @Inject
+    public TransportCreatePitAction(
+        TransportService transportService,
+        ActionFilters actionFilters,
+        SearchTransportService searchTransportService,
+        ClusterService clusterService,
+        TransportSearchAction transportSearchAction,
+        NamedWriteableRegistry namedWriteableRegistry,
+        CreatePitController createPitController
+    ) {
+        super(CreatePitAction.NAME, transportService, actionFilters, in -> new CreatePitRequest(in));
+        this.transportService = transportService;
+        this.searchTransportService = searchTransportService;
+        this.clusterService = clusterService;
+        this.transportSearchAction = transportSearchAction;
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        this.createPitController = createPitController;
+    }
+
+    @Override
+    protected void doExecute(Task task, CreatePitRequest request, ActionListener<CreatePitResponse> listener) {
+        final StepListener<SearchResponse> createPitListener = new StepListener<>();
+        final ActionListener<CreatePitResponse> updatePitIdListener = ActionListener.wrap(r -> listener.onResponse(r), e -> {
+            logger.error(
+                () -> new ParameterizedMessage(
+                    "PIT creation failed while updating PIT ID for indices [{}]",
+                    Arrays.toString(request.indices())
+                )
+            );
+            listener.onFailure(e);
+        });
+        createPitController.executeCreatePit(request, task, createPitListener, updatePitIdListener);
+    }
+
+    /**
+     * Request to create pit reader context with keep alive
+     */
+    public static class CreateReaderContextRequest extends TransportRequest {
+        private final ShardId shardId;
+        private final TimeValue keepAlive;
+
+        public CreateReaderContextRequest(ShardId shardId, TimeValue keepAlive) {
+            this.shardId = shardId;
+            this.keepAlive = keepAlive;
+        }
+
+        public ShardId getShardId() {
+            return shardId;
+        }
+
+        public TimeValue getKeepAlive() {
+            return keepAlive;
+        }
+
+        public CreateReaderContextRequest(StreamInput in) throws IOException {
+            super(in);
+            this.shardId = new ShardId(in);
+            this.keepAlive = in.readTimeValue();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            shardId.writeTo(out);
+            out.writeTimeValue(keepAlive);
+        }
+    }
+
+    /**
+     * Create pit reader context response which holds the contextId
+     */
+    public static class CreateReaderContextResponse extends SearchPhaseResult {
+        public CreateReaderContextResponse(ShardSearchContextId shardSearchContextId) {
+            this.contextId = shardSearchContextId;
+        }
+
+        public CreateReaderContextResponse(StreamInput in) throws IOException {
+            super(in);
+            contextId = new ShardSearchContextId(in);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            contextId.writeTo(out);
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/search/TransportDeletePitAction.java b/server/src/main/java/org/opensearch/action/search/TransportDeletePitAction.java
new file mode 100644
index 0000000000000..614d576324026
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/TransportDeletePitAction.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.tasks.Task;
+import org.opensearch.transport.TransportService;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Transport action for deleting point in time searches - supports deleting list and all point in time searches
+ */
+public class TransportDeletePitAction extends HandledTransportAction<DeletePitRequest, DeletePitResponse> {
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final PitService pitService;
+
+    @Inject
+    public TransportDeletePitAction(
+        TransportService transportService,
+        ActionFilters actionFilters,
+        NamedWriteableRegistry namedWriteableRegistry,
+        PitService pitService
+    ) {
+        super(DeletePitAction.NAME, transportService, actionFilters, DeletePitRequest::new);
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        this.pitService = pitService;
+    }
+
+    /**
+     * Invoke 'delete all pits' or 'delete list of pits' workflow based on request
+     */
+    @Override
+    protected void doExecute(Task task, DeletePitRequest request, ActionListener<DeletePitResponse> listener) {
+        if (request.getPitIds().size() == 1 && "_all".equals(request.getPitIds().get(0))) {
+            deleteAllPits(listener);
+        } else {
+            deletePits(listener, request);
+        }
+    }
+
+    /**
+     * Deletes one or more point in time search contexts.
+     */
+    private void deletePits(ActionListener<DeletePitResponse> listener, DeletePitRequest request) {
+        Map<String, List<PitSearchContextIdForNode>> nodeToContextsMap = new HashMap<>();
+        // remove duplicates from the request
+        Set<String> uniquePitIds = new LinkedHashSet<>(request.getPitIds());
+        for (String pitId : uniquePitIds) {
+            SearchContextId contextId = SearchContextId.decode(namedWriteableRegistry, pitId);
+            for (SearchContextIdForNode contextIdForNode : contextId.shards().values()) {
+                PitSearchContextIdForNode pitSearchContext = new PitSearchContextIdForNode(pitId, contextIdForNode);
+                List<PitSearchContextIdForNode> contexts = nodeToContextsMap.getOrDefault(contextIdForNode.getNode(), new ArrayList<>());
+                contexts.add(pitSearchContext);
+                nodeToContextsMap.put(contextIdForNode.getNode(), contexts);
+            }
+        }
+        pitService.deletePitContexts(nodeToContextsMap, listener);
+    }
+
+    /**
+     * Delete all active PIT reader contexts leveraging list all PITs
+     *
+     * For Cross cluster PITs :
+     * - mixed cluster PITs ( PIT comprising local and remote ) will be fully deleted. Since there will atleast be
+     * one reader context with PIT ID present in local cluster, 'Get all PITs' will retrieve the PIT ID with which
+     * we can completely delete the PIT contexts in both local and remote cluster.
+     * - fully remote PITs will not be deleted as 'Get all PITs' operates on local cluster only and no PIT info can
+     * be retrieved when it's fully remote.
+     */
+    private void deleteAllPits(ActionListener<DeletePitResponse> listener) {
+        // Get all PITs and execute delete operation for the PITs.
+        pitService.getAllPits(ActionListener.wrap(getAllPitNodesResponse -> {
+            DeletePitRequest deletePitRequest = new DeletePitRequest(
+                getAllPitNodesResponse.getPitInfos().stream().map(r -> r.getPitId()).collect(Collectors.toList())
+            );
+            deletePits(listener, deletePitRequest);
+        }, listener::onFailure));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/TransportGetAllPitsAction.java b/server/src/main/java/org/opensearch/action/search/TransportGetAllPitsAction.java
new file mode 100644
index 0000000000000..561ca034da469
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/TransportGetAllPitsAction.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.action.FailedNodeException;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.nodes.TransportNodesAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.search.SearchService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * Transport action to get all active PIT contexts across all nodes
+ */
+public class TransportGetAllPitsAction extends TransportNodesAction<
+    GetAllPitNodesRequest,
+    GetAllPitNodesResponse,
+    GetAllPitNodeRequest,
+    GetAllPitNodeResponse> {
+    private final SearchService searchService;
+
+    @Inject
+    public TransportGetAllPitsAction(
+        ThreadPool threadPool,
+        ClusterService clusterService,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        SearchService searchService
+    ) {
+        super(
+            GetAllPitsAction.NAME,
+            threadPool,
+            clusterService,
+            transportService,
+            actionFilters,
+            GetAllPitNodesRequest::new,
+            GetAllPitNodeRequest::new,
+            ThreadPool.Names.SAME,
+            GetAllPitNodeResponse.class
+        );
+        this.searchService = searchService;
+    }
+
+    @Override
+    protected GetAllPitNodesResponse newResponse(
+        GetAllPitNodesRequest request,
+        List<GetAllPitNodeResponse> getAllPitNodeResponses,
+        List<FailedNodeException> failures
+    ) {
+        return new GetAllPitNodesResponse(clusterService.getClusterName(), getAllPitNodeResponses, failures);
+    }
+
+    @Override
+    protected GetAllPitNodeRequest newNodeRequest(GetAllPitNodesRequest request) {
+        return new GetAllPitNodeRequest();
+    }
+
+    @Override
+    protected GetAllPitNodeResponse newNodeResponse(StreamInput in) throws IOException {
+        return new GetAllPitNodeResponse(in);
+    }
+
+    /**
+     * This retrieves all active PITs in the node
+     */
+    @Override
+    protected GetAllPitNodeResponse nodeOperation(GetAllPitNodeRequest request) {
+        GetAllPitNodeResponse nodeResponse = new GetAllPitNodeResponse(
+            transportService.getLocalNode(),
+            searchService.getAllPITReaderContexts()
+        );
+        return nodeResponse;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/TransportMultiSearchAction.java b/server/src/main/java/org/opensearch/action/search/TransportMultiSearchAction.java
index 6c54136254832..146b4010af4b3 100644
--- a/server/src/main/java/org/opensearch/action/search/TransportMultiSearchAction.java
+++ b/server/src/main/java/org/opensearch/action/search/TransportMultiSearchAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.node.NodeClient;
@@ -40,10 +39,11 @@
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -54,6 +54,11 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.LongSupplier;
 
+/**
+ * Perform action for a multi search
+ *
+ * @opensearch.internal
+ */
 public class TransportMultiSearchAction extends HandledTransportAction<MultiSearchRequest, MultiSearchResponse> {
 
     private final int allocatedProcessors;
@@ -215,6 +220,11 @@ private long buildTookInMillis() {
         });
     }
 
+    /**
+     * Slots a search request
+     *
+     * @opensearch.internal
+     */
     static final class SearchRequestSlot {
 
         final SearchRequest request;
diff --git a/server/src/main/java/org/opensearch/action/search/TransportSearchAction.java b/server/src/main/java/org/opensearch/action/search/TransportSearchAction.java
index 73eb7b0a98fef..cff1005beff27 100644
--- a/server/src/main/java/org/opensearch/action/search/TransportSearchAction.java
+++ b/server/src/main/java/org/opensearch/action/search/TransportSearchAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsGroup;
@@ -57,20 +56,23 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.query.Rewriteable;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.SearchShardTarget;
@@ -80,11 +82,12 @@
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.pipeline.PipelinedRequest;
+import org.opensearch.search.pipeline.SearchPipelineService;
 import org.opensearch.search.profile.ProfileShardResult;
 import org.opensearch.search.profile.SearchProfileShardResults;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterAware;
 import org.opensearch.transport.RemoteClusterService;
@@ -117,6 +120,11 @@
 import static org.opensearch.action.search.SearchType.QUERY_THEN_FETCH;
 import static org.opensearch.search.sort.FieldSortBuilder.hasPrimaryFieldSort;
 
+/**
+ * Perform search action
+ *
+ * @opensearch.internal
+ */
 public class TransportSearchAction extends HandledTransportAction<SearchRequest, SearchResponse> {
 
     /** The maximum number of shards for a single search request. */
@@ -138,6 +146,14 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
         Setting.Property.NodeScope
     );
 
+    public static final String SEARCH_REQUEST_STATS_ENABLED_KEY = "search.request_stats_enabled";
+    public static final Setting<Boolean> SEARCH_REQUEST_STATS_ENABLED = Setting.boolSetting(
+        SEARCH_REQUEST_STATS_ENABLED_KEY,
+        false,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     private final NodeClient client;
     private final ThreadPool threadPool;
     private final ClusterService clusterService;
@@ -148,6 +164,11 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
     private final IndexNameExpressionResolver indexNameExpressionResolver;
     private final NamedWriteableRegistry namedWriteableRegistry;
     private final CircuitBreaker circuitBreaker;
+    private final SearchPipelineService searchPipelineService;
+
+    private volatile boolean isRequestStatsEnabled;
+
+    private final SearchRequestStats searchRequestStats;
 
     @Inject
     public TransportSearchAction(
@@ -161,7 +182,9 @@ public TransportSearchAction(
         ClusterService clusterService,
         ActionFilters actionFilters,
         IndexNameExpressionResolver indexNameExpressionResolver,
-        NamedWriteableRegistry namedWriteableRegistry
+        NamedWriteableRegistry namedWriteableRegistry,
+        SearchPipelineService searchPipelineService,
+        SearchRequestStats searchRequestStats
     ) {
         super(SearchAction.NAME, transportService, actionFilters, (Writeable.Reader<SearchRequest>) SearchRequest::new);
         this.client = client;
@@ -175,6 +198,14 @@ public TransportSearchAction(
         this.searchService = searchService;
         this.indexNameExpressionResolver = indexNameExpressionResolver;
         this.namedWriteableRegistry = namedWriteableRegistry;
+        this.searchPipelineService = searchPipelineService;
+        this.isRequestStatsEnabled = clusterService.getClusterSettings().get(SEARCH_REQUEST_STATS_ENABLED);
+        clusterService.getClusterSettings().addSettingsUpdateConsumer(SEARCH_REQUEST_STATS_ENABLED, this::setIsRequestStatsEnabled);
+        this.searchRequestStats = searchRequestStats;
+    }
+
+    private void setIsRequestStatsEnabled(boolean isRequestStatsEnabled) {
+        this.isRequestStatsEnabled = isRequestStatsEnabled;
     }
 
     private Map<String, AliasFilter> buildPerIndexAliasFilter(
@@ -227,6 +258,8 @@ private Map<String, Float> resolveIndexBoosts(SearchRequest searchRequest, Clust
      * clock for measuring how long an operation took (they often lack precision, they are subject
      * to moving backwards due to NTP and other such complexities, etc.). There are also issues with
      * using a relative clock for reporting real time. Thus, we simply separate these two uses.
+     *
+     * @opensearch.internal
      */
     static final class SearchTimeProvider {
 
@@ -277,6 +310,11 @@ protected void doExecute(Task task, SearchRequest searchRequest, ActionListener<
         executeRequest(task, searchRequest, this::searchAsyncAction, listener);
     }
 
+    /**
+     * The single phase search action.
+     *
+     * @opensearch.internal
+     */
     public interface SinglePhaseSearchAction {
         void executeOnShardTarget(
             SearchTask searchTask,
@@ -294,6 +332,13 @@ public void executeRequest(
         SinglePhaseSearchAction phaseSearchAction,
         ActionListener<SearchResponse> listener
     ) {
+        final List<SearchRequestOperationsListener> searchListenersList = createSearchListenerList();
+        final SearchRequestOperationsListener searchRequestOperationsListener;
+        if (!CollectionUtils.isEmpty(searchListenersList)) {
+            searchRequestOperationsListener = new SearchRequestOperationsListener.CompositeListener(searchListenersList, logger);
+        } else {
+            searchRequestOperationsListener = null;
+        }
         executeRequest(task, searchRequest, new SearchAsyncActionProvider() {
             @Override
             public AbstractSearchAsyncAction<? extends SearchPhaseResult> asyncSearchAction(
@@ -328,8 +373,9 @@ public AbstractSearchAsyncAction<? extends SearchPhaseResult> asyncSearchAction(
                     clusterState,
                     task,
                     new ArraySearchPhaseResults<>(shardsIts.size()),
-                    1,
-                    clusters
+                    searchRequest.getMaxConcurrentShardRequests(),
+                    clusters,
+                    searchRequestOperationsListener
                 ) {
                     @Override
                     protected void executePhaseOnShard(
@@ -363,16 +409,29 @@ boolean buildPointInTimeFromSearchResults() {
 
     private void executeRequest(
         Task task,
-        SearchRequest searchRequest,
+        SearchRequest originalSearchRequest,
         SearchAsyncActionProvider searchAsyncActionProvider,
-        ActionListener<SearchResponse> listener
+        ActionListener<SearchResponse> originalListener
     ) {
         final long relativeStartNanos = System.nanoTime();
         final SearchTimeProvider timeProvider = new SearchTimeProvider(
-            searchRequest.getOrCreateAbsoluteStartMillis(),
+            originalSearchRequest.getOrCreateAbsoluteStartMillis(),
             relativeStartNanos,
             System::nanoTime
         );
+        PipelinedRequest searchRequest;
+        ActionListener<SearchResponse> listener;
+        try {
+            searchRequest = searchPipelineService.resolvePipeline(originalSearchRequest);
+            listener = ActionListener.wrap(
+                r -> originalListener.onResponse(searchRequest.transformResponse(r)),
+                originalListener::onFailure
+            );
+        } catch (Exception e) {
+            originalListener.onFailure(e);
+            return;
+        }
+
         ActionListener<SearchSourceBuilder> rewriteListener = ActionListener.wrap(source -> {
             if (source != searchRequest.source()) {
                 // only set it if it changed - we don't allow null values to be set but it might be already null. this way we catch
@@ -412,7 +471,7 @@ private void executeRequest(
                         localIndices,
                         remoteClusterIndices,
                         timeProvider,
-                        searchService.aggReduceContextBuilder(searchRequest),
+                        searchService.aggReduceContextBuilder(searchRequest.source()),
                         remoteClusterService,
                         threadPool,
                         listener,
@@ -886,9 +945,7 @@ private void executeSearch(
         @Nullable SearchContextId searchContext,
         SearchAsyncActionProvider searchAsyncActionProvider
     ) {
-
         clusterState.blocks().globalBlockedRaiseException(ClusterBlockLevel.READ);
-
         // TODO: I think startTime() should become part of ActionRequest and that should be used both for index name
         // date math expressions and $now in scripts. This way all apis will deal with now in the same way instead
         // of just for the _search api
@@ -938,11 +995,8 @@ private void executeSearch(
             indexRoutings = routingMap;
         }
         final GroupShardsIterator<SearchShardIterator> shardIterators = mergeShardsIterators(localShardIterators, remoteShardIterators);
-
         failIfOverShardCountLimit(clusterService, shardIterators.size());
-
         Map<String, Float> concreteIndexBoosts = resolveIndexBoosts(searchRequest, clusterState);
-
         // optimize search type for cases where there is only one shard group to search on
         if (shardIterators.size() == 1) {
             // if we only have one group, then we always want Q_T_F, no need for DFS, and no need to do THEN since we hit one shard
@@ -1077,6 +1131,14 @@ AbstractSearchAsyncAction<? extends SearchPhaseResult> asyncSearchAction(
         );
     }
 
+    private List<SearchRequestOperationsListener> createSearchListenerList() {
+        final List<SearchRequestOperationsListener> searchListenersList = new ArrayList<>();
+        if (isRequestStatsEnabled) {
+            searchListenersList.add(searchRequestStats);
+        }
+        return searchListenersList;
+    }
+
     private AbstractSearchAsyncAction<? extends SearchPhaseResult> searchAsyncAction(
         SearchTask task,
         SearchRequest searchRequest,
@@ -1093,6 +1155,13 @@ private AbstractSearchAsyncAction<? extends SearchPhaseResult> searchAsyncAction
         ThreadPool threadPool,
         SearchResponse.Clusters clusters
     ) {
+        final List<SearchRequestOperationsListener> searchListenersList = createSearchListenerList();
+        final SearchRequestOperationsListener searchRequestOperationsListener;
+        if (!CollectionUtils.isEmpty(searchListenersList)) {
+            searchRequestOperationsListener = new SearchRequestOperationsListener.CompositeListener(searchListenersList, logger);
+        } else {
+            searchRequestOperationsListener = null;
+        }
         if (preFilter) {
             return new CanMatchPreFilterSearchPhase(
                 logger,
@@ -1132,7 +1201,8 @@ public void run() {
                         }
                     };
                 },
-                clusters
+                clusters,
+                searchRequestOperationsListener
             );
         } else {
             final QueryPhaseResultConsumer queryResultConsumer = searchPhaseController.newSearchPhaseResults(
@@ -1162,7 +1232,8 @@ public void run() {
                         timeProvider,
                         clusterState,
                         task,
-                        clusters
+                        clusters,
+                        searchRequestOperationsListener
                     );
                     break;
                 case QUERY_THEN_FETCH:
@@ -1182,7 +1253,8 @@ public void run() {
                         timeProvider,
                         clusterState,
                         task,
-                        clusters
+                        clusters,
+                        searchRequestOperationsListener
                     );
                     break;
                 default:
@@ -1217,6 +1289,11 @@ private static void failIfOverShardCountLimit(ClusterService clusterService, int
         }
     }
 
+    /**
+     * xcluster search listener
+     *
+     * @opensearch.internal
+     */
     abstract static class CCSActionListener<Response, FinalResponse> implements ActionListener<Response> {
         private final String clusterAlias;
         private final boolean skipUnavailable;
diff --git a/server/src/main/java/org/opensearch/action/search/TransportSearchHelper.java b/server/src/main/java/org/opensearch/action/search/TransportSearchHelper.java
index 7ddfdfec34cb1..afe76138edef3 100644
--- a/server/src/main/java/org/opensearch/action/search/TransportSearchHelper.java
+++ b/server/src/main/java/org/opensearch/action/search/TransportSearchHelper.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.BytesStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
@@ -48,6 +48,11 @@
 import java.io.UncheckedIOException;
 import java.util.Base64;
 
+/**
+ * Helper class for the search transport
+ *
+ * @opensearch.internal
+ */
 final class TransportSearchHelper {
 
     private static final String INCLUDE_CONTEXT_UUID = "include_context_uuid";
diff --git a/server/src/main/java/org/opensearch/action/search/TransportSearchScrollAction.java b/server/src/main/java/org/opensearch/action/search/TransportSearchScrollAction.java
index cb7c0b4a1873b..4713d03c93bac 100644
--- a/server/src/main/java/org/opensearch/action/search/TransportSearchScrollAction.java
+++ b/server/src/main/java/org/opensearch/action/search/TransportSearchScrollAction.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Perform the search scroll
+ *
+ * @opensearch.internal
+ */
 public class TransportSearchScrollAction extends HandledTransportAction<SearchScrollRequest, SearchResponse> {
 
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/search/UpdatePitContextRequest.java b/server/src/main/java/org/opensearch/action/search/UpdatePitContextRequest.java
new file mode 100644
index 0000000000000..0d10390f1f660
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/UpdatePitContextRequest.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+
+/**
+ * Request used to update PIT reader contexts with pitId, keepAlive and creationTime
+ */
+public class UpdatePitContextRequest extends TransportRequest {
+    private final String pitId;
+    private final long keepAlive;
+
+    private final long creationTime;
+    private final ShardSearchContextId searchContextId;
+
+    public UpdatePitContextRequest(ShardSearchContextId searchContextId, String pitId, long keepAlive, long creationTime) {
+        this.pitId = pitId;
+        this.searchContextId = searchContextId;
+        this.keepAlive = keepAlive;
+        this.creationTime = creationTime;
+    }
+
+    UpdatePitContextRequest(StreamInput in) throws IOException {
+        super(in);
+        pitId = in.readString();
+        keepAlive = in.readLong();
+        creationTime = in.readLong();
+        searchContextId = new ShardSearchContextId(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(pitId);
+        out.writeLong(keepAlive);
+        out.writeLong(creationTime);
+        searchContextId.writeTo(out);
+    }
+
+    public ShardSearchContextId getSearchContextId() {
+        return searchContextId;
+    }
+
+    public String getPitId() {
+        return pitId;
+    }
+
+    public long getCreationTime() {
+        return creationTime;
+    }
+
+    public long getKeepAlive() {
+        return keepAlive;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/search/UpdatePitContextResponse.java b/server/src/main/java/org/opensearch/action/search/UpdatePitContextResponse.java
new file mode 100644
index 0000000000000..1db8fc48c28bc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/search/UpdatePitContextResponse.java
@@ -0,0 +1,58 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+
+/**
+ * Update PIT context response with creation time, keep alive etc.
+ */
+public class UpdatePitContextResponse extends TransportResponse {
+    private final String pitId;
+
+    private final long creationTime;
+
+    private final long keepAlive;
+
+    UpdatePitContextResponse(StreamInput in) throws IOException {
+        super(in);
+        pitId = in.readString();
+        creationTime = in.readLong();
+        keepAlive = in.readLong();
+    }
+
+    public UpdatePitContextResponse(String pitId, long creationTime, long keepAlive) {
+        this.pitId = pitId;
+        this.keepAlive = keepAlive;
+        this.creationTime = creationTime;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(pitId);
+        out.writeLong(creationTime);
+        out.writeLong(keepAlive);
+    }
+
+    public String getPitId() {
+        return pitId;
+    }
+
+    public long getKeepAlive() {
+        return keepAlive;
+    }
+
+    public long getCreationTime() {
+        return creationTime;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/ActionFilter.java b/server/src/main/java/org/opensearch/action/support/ActionFilter.java
index 414ef2a329214..e936512004fd2 100644
--- a/server/src/main/java/org/opensearch/action/support/ActionFilter.java
+++ b/server/src/main/java/org/opensearch/action/support/ActionFilter.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.tasks.Task;
 
 /**
  * A filter allowing to filter transport actions
+ *
+ * @opensearch.internal
  */
 public interface ActionFilter {
 
diff --git a/server/src/main/java/org/opensearch/action/support/ActionFilterChain.java b/server/src/main/java/org/opensearch/action/support/ActionFilterChain.java
index 65821f14167f7..1ebe1ee63abf9 100644
--- a/server/src/main/java/org/opensearch/action/support/ActionFilterChain.java
+++ b/server/src/main/java/org/opensearch/action/support/ActionFilterChain.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.tasks.Task;
 
 /**
  * A filter chain allowing to continue and process the transport action request
+ *
+ * @opensearch.internal
  */
 public interface ActionFilterChain<Request extends ActionRequest, Response extends ActionResponse> {
 
diff --git a/server/src/main/java/org/opensearch/action/support/ActionFilters.java b/server/src/main/java/org/opensearch/action/support/ActionFilters.java
index 452b7e7f5238f..95cafbea4d7c1 100644
--- a/server/src/main/java/org/opensearch/action/support/ActionFilters.java
+++ b/server/src/main/java/org/opensearch/action/support/ActionFilters.java
@@ -38,6 +38,8 @@
 
 /**
  * Holds the action filters injected through plugins, properly sorted by {@link org.opensearch.action.support.ActionFilter#order()}
+ *
+ * @opensearch.internal
  */
 public class ActionFilters {
 
diff --git a/server/src/main/java/org/opensearch/action/support/ActiveShardCount.java b/server/src/main/java/org/opensearch/action/support/ActiveShardCount.java
index 9edd9bba0ef6e..15275ba48fc6e 100644
--- a/server/src/main/java/org/opensearch/action/support/ActiveShardCount.java
+++ b/server/src/main/java/org/opensearch/action/support/ActiveShardCount.java
@@ -32,15 +32,13 @@
 
 package org.opensearch.action.support;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -49,6 +47,8 @@
 /**
  * A class whose instances represent a value for counting the number
  * of active shard copies for a given shard in an index.
+ *
+ * @opensearch.internal
  */
 public final class ActiveShardCount implements Writeable {
 
@@ -184,8 +184,8 @@ public boolean enoughShardsActive(final ClusterState clusterState, final String.
             if (waitForActiveShards == ActiveShardCount.DEFAULT) {
                 waitForActiveShards = SETTING_WAIT_FOR_ACTIVE_SHARDS.get(indexMetadata.getSettings());
             }
-            for (final IntObjectCursor<IndexShardRoutingTable> shardRouting : indexRoutingTable.getShards()) {
-                if (waitForActiveShards.enoughShardsActive(shardRouting.value) == false) {
+            for (final IndexShardRoutingTable shardRouting : indexRoutingTable.getShards().values()) {
+                if (waitForActiveShards.enoughShardsActive(shardRouting) == false) {
                     // not enough active shard copies yet
                     return false;
                 }
diff --git a/server/src/main/java/org/opensearch/action/support/ActiveShardsObserver.java b/server/src/main/java/org/opensearch/action/support/ActiveShardsObserver.java
index 064ae2ee522f9..29468fe777707 100644
--- a/server/src/main/java/org/opensearch/action/support/ActiveShardsObserver.java
+++ b/server/src/main/java/org/opensearch/action/support/ActiveShardsObserver.java
@@ -34,11 +34,11 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -49,6 +49,8 @@
 /**
  * This class provides primitives for waiting for a configured number of shards
  * to become active before sending a response on an {@link ActionListener}.
+ *
+ * @opensearch.internal
  */
 public class ActiveShardsObserver {
 
diff --git a/server/src/main/java/org/opensearch/action/support/AdapterActionFuture.java b/server/src/main/java/org/opensearch/action/support/AdapterActionFuture.java
index aa197d1e255f9..cfc867c572a75 100644
--- a/server/src/main/java/org/opensearch/action/support/AdapterActionFuture.java
+++ b/server/src/main/java/org/opensearch/action/support/AdapterActionFuture.java
@@ -33,15 +33,20 @@
 package org.opensearch.action.support;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.BaseFuture;
 import org.opensearch.common.util.concurrent.FutureUtils;
 import org.opensearch.common.util.concurrent.UncategorizedExecutionException;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Future adapter action
+ *
+ * @opensearch.internal
+ */
 public abstract class AdapterActionFuture<T, L> extends BaseFuture<T> implements ActionFuture<T>, ActionListener<L> {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/support/AutoCreateIndex.java b/server/src/main/java/org/opensearch/action/support/AutoCreateIndex.java
index 322dfc85fbf54..9e8cbd7bf40c2 100644
--- a/server/src/main/java/org/opensearch/action/support/AutoCreateIndex.java
+++ b/server/src/main/java/org/opensearch/action/support/AutoCreateIndex.java
@@ -35,13 +35,13 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.SystemIndices;
@@ -52,6 +52,8 @@
 /**
  * Encapsulates the logic of whether a new index should be automatically created when
  * a write operation is about to happen in a non existing index.
+ *
+ * @opensearch.internal
  */
 public final class AutoCreateIndex {
 
@@ -142,6 +144,11 @@ void setAutoCreate(AutoCreate autoCreate) {
         this.autoCreate = autoCreate;
     }
 
+    /**
+     * An auto create object
+     *
+     * @opensearch.internal
+     */
     static class AutoCreate {
         private final boolean autoCreateIndex;
         private final List<Tuple<String, Boolean>> expressions;
diff --git a/server/src/main/java/org/opensearch/action/support/ChannelActionListener.java b/server/src/main/java/org/opensearch/action/support/ChannelActionListener.java
index 288c91b243cb1..ac5dfeb4728d5 100644
--- a/server/src/main/java/org/opensearch/action/support/ChannelActionListener.java
+++ b/server/src/main/java/org/opensearch/action/support/ChannelActionListener.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
 
+/**
+ * Listener for transport channel actions
+ *
+ * @opensearch.internal
+ */
 public final class ChannelActionListener<Response extends TransportResponse, Request extends TransportRequest>
     implements
         ActionListener<Response> {
diff --git a/server/src/main/java/org/opensearch/action/support/ContextPreservingActionListener.java b/server/src/main/java/org/opensearch/action/support/ContextPreservingActionListener.java
index b83e0541cb6d0..a59c7fb45ca27 100644
--- a/server/src/main/java/org/opensearch/action/support/ContextPreservingActionListener.java
+++ b/server/src/main/java/org/opensearch/action/support/ContextPreservingActionListener.java
@@ -31,14 +31,16 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.function.Supplier;
 
 /**
  * Restores the given {@link org.opensearch.common.util.concurrent.ThreadContext.StoredContext}
  * once the listener is invoked
+ *
+ * @opensearch.internal
  */
 public final class ContextPreservingActionListener<R> implements ActionListener<R> {
 
diff --git a/server/src/main/java/org/opensearch/action/support/DestructiveOperations.java b/server/src/main/java/org/opensearch/action/support/DestructiveOperations.java
index ce9a0d7c7aece..84b3287322301 100644
--- a/server/src/main/java/org/opensearch/action/support/DestructiveOperations.java
+++ b/server/src/main/java/org/opensearch/action/support/DestructiveOperations.java
@@ -39,6 +39,8 @@
 
 /**
  * Helper for dealing with destructive operations and wildcard usage.
+ *
+ * @opensearch.internal
  */
 public final class DestructiveOperations {
 
diff --git a/server/src/main/java/org/opensearch/action/support/GroupedActionListener.java b/server/src/main/java/org/opensearch/action/support/GroupedActionListener.java
index 515ed73ae2392..fb9554cc4c3d2 100644
--- a/server/src/main/java/org/opensearch/action/support/GroupedActionListener.java
+++ b/server/src/main/java/org/opensearch/action/support/GroupedActionListener.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -46,6 +46,8 @@
  * it has received N results (either successes or failures). This allows synchronous
  * tasks to be forked off in a loop with the same listener and respond to a
  * higher level listener once all tasks responded.
+ *
+ * @opensearch.internal
  */
 public final class GroupedActionListener<T> implements ActionListener<T> {
     private final CountDown countDown;
diff --git a/server/src/main/java/org/opensearch/action/support/HandledTransportAction.java b/server/src/main/java/org/opensearch/action/support/HandledTransportAction.java
index 9613b55cc7641..786d8cfb6fa1d 100644
--- a/server/src/main/java/org/opensearch/action/support/HandledTransportAction.java
+++ b/server/src/main/java/org/opensearch/action/support/HandledTransportAction.java
@@ -32,8 +32,8 @@
 package org.opensearch.action.support;
 
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportChannel;
@@ -42,6 +42,8 @@
 
 /**
  * A TransportAction that self registers a handler into the transport service
+ *
+ * @opensearch.internal
  */
 public abstract class HandledTransportAction<Request extends ActionRequest, Response extends ActionResponse> extends TransportAction<
     Request,
@@ -88,6 +90,11 @@ protected HandledTransportAction(
         transportService.registerRequestHandler(actionName, executor, false, canTripCircuitBreaker, requestReader, new TransportHandler());
     }
 
+    /**
+     * Inner transport handler
+     *
+     * @opensearch.internal
+     */
     class TransportHandler implements TransportRequestHandler<Request> {
         @Override
         public final void messageReceived(final Request request, final TransportChannel channel, Task task) {
diff --git a/server/src/main/java/org/opensearch/action/support/IndicesOptions.java b/server/src/main/java/org/opensearch/action/support/IndicesOptions.java
index 09b691787dffe..351868b704dde 100644
--- a/server/src/main/java/org/opensearch/action/support/IndicesOptions.java
+++ b/server/src/main/java/org/opensearch/action/support/IndicesOptions.java
@@ -33,14 +33,14 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.rest.RestRequest;
 
 import java.io.IOException;
@@ -55,9 +55,16 @@
 /**
  * Controls how to deal with unavailable concrete indices (closed or missing), how wildcard expressions are expanded
  * to actual indices (all, closed or open indices) and how to deal with wildcard expressions that resolve to no indices.
+ *
+ * @opensearch.internal
  */
 public class IndicesOptions implements ToXContentFragment {
 
+    /**
+     * The wildcard states.
+     *
+     * @opensearch.internal
+     */
     public enum WildcardStates {
         OPEN,
         CLOSED,
@@ -118,6 +125,11 @@ private static void updateSetForValue(EnumSet<WildcardStates> states, String wil
         }
     }
 
+    /**
+     * The options.
+     *
+     * @opensearch.internal
+     */
     public enum Option {
         IGNORE_UNAVAILABLE,
         IGNORE_ALIASES,
diff --git a/server/src/main/java/org/opensearch/action/support/ListenerTimeouts.java b/server/src/main/java/org/opensearch/action/support/ListenerTimeouts.java
index c31ca9b100624..6020dc2bfd489 100644
--- a/server/src/main/java/org/opensearch/action/support/ListenerTimeouts.java
+++ b/server/src/main/java/org/opensearch/action/support/ListenerTimeouts.java
@@ -33,14 +33,19 @@
 package org.opensearch.action.support;
 
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Consumer;
 
+/**
+ * Supports timeouts on listeners
+ *
+ * @opensearch.internal
+ */
 public class ListenerTimeouts {
 
     /**
@@ -91,6 +96,11 @@ public static <Response> ActionListener<Response> wrapWithTimeout(
         return wrappedListener;
     }
 
+    /**
+     * Listener that can time out
+     *
+     * @opensearch.internal
+     */
     private static class TimeoutableListener<Response> implements ActionListener<Response>, Runnable {
 
         private final AtomicBoolean isDone = new AtomicBoolean(false);
diff --git a/server/src/main/java/org/opensearch/action/support/PlainActionFuture.java b/server/src/main/java/org/opensearch/action/support/PlainActionFuture.java
index d7235a3b0ee46..abe63d8abd473 100644
--- a/server/src/main/java/org/opensearch/action/support/PlainActionFuture.java
+++ b/server/src/main/java/org/opensearch/action/support/PlainActionFuture.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.CheckedConsumer;
 
+/**
+ * Creates a new future for a plain action.
+ *
+ * @opensearch.internal
+ */
 public class PlainActionFuture<T> extends AdapterActionFuture<T, T> {
 
     public static <T> PlainActionFuture<T> newFuture() {
diff --git a/server/src/main/java/org/opensearch/action/support/PlainListenableActionFuture.java b/server/src/main/java/org/opensearch/action/support/PlainListenableActionFuture.java
index 16a82b91145ae..1b16249f70754 100644
--- a/server/src/main/java/org/opensearch/action/support/PlainListenableActionFuture.java
+++ b/server/src/main/java/org/opensearch/action/support/PlainListenableActionFuture.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ListenableActionFuture;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Future for a plain listenable action
+ *
+ * @opensearch.internal
+ */
 public class PlainListenableActionFuture<T> extends AdapterActionFuture<T, T> implements ListenableActionFuture<T> {
 
     volatile Object listeners;
diff --git a/server/src/main/java/org/opensearch/action/support/RetryableAction.java b/server/src/main/java/org/opensearch/action/support/RetryableAction.java
index e330948209b5c..fc2ee277b538a 100644
--- a/server/src/main/java/org/opensearch/action/support/RetryableAction.java
+++ b/server/src/main/java/org/opensearch/action/support/RetryableAction.java
@@ -34,15 +34,16 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
-import org.opensearch.common.Randomness;
+import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.ArrayDeque;
+import java.util.Iterator;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
@@ -50,6 +51,8 @@
  * The executor the action will be executed on can be defined in the constructor. Otherwise, SAME is the
  * default. The action will be retried with exponentially increasing delay periods until the timeout period
  * has been reached.
+ *
+ * @opensearch.internal
  */
 public abstract class RetryableAction<Response> {
 
@@ -62,6 +65,7 @@ public abstract class RetryableAction<Response> {
     private final long startMillis;
     private final ActionListener<Response> finalListener;
     private final String executor;
+    private final BackoffPolicy backoffPolicy;
 
     private volatile Scheduler.ScheduledCancellable retryTask;
 
@@ -72,7 +76,15 @@ public RetryableAction(
         TimeValue timeoutValue,
         ActionListener<Response> listener
     ) {
-        this(logger, threadPool, initialDelay, timeoutValue, listener, ThreadPool.Names.SAME);
+        this(
+            logger,
+            threadPool,
+            initialDelay,
+            timeoutValue,
+            listener,
+            BackoffPolicy.exponentialFullJitterBackoff(initialDelay.getMillis()),
+            ThreadPool.Names.SAME
+        );
     }
 
     public RetryableAction(
@@ -81,6 +93,7 @@ public RetryableAction(
         TimeValue initialDelay,
         TimeValue timeoutValue,
         ActionListener<Response> listener,
+        BackoffPolicy backoffPolicy,
         String executor
     ) {
         this.logger = logger;
@@ -93,10 +106,11 @@ public RetryableAction(
         this.startMillis = threadPool.relativeTimeInMillis();
         this.finalListener = listener;
         this.executor = executor;
+        this.backoffPolicy = backoffPolicy;
     }
 
     public void run() {
-        final RetryingListener retryingListener = new RetryingListener(initialDelayMillis, null);
+        final RetryingListener retryingListener = new RetryingListener(backoffPolicy.iterator(), null);
         final Runnable runnable = createRunnable(retryingListener);
         threadPool.executor(executor).execute(runnable);
     }
@@ -140,16 +154,24 @@ public void onRejection(Exception e) {
 
     public void onFinished() {}
 
+    /**
+     * Retry able task may want to throw different Exception on timeout,
+     * they can override it method for that.
+     */
+    public Exception getTimeoutException(Exception e) {
+        return e;
+    }
+
     private class RetryingListener implements ActionListener<Response> {
 
         private static final int MAX_EXCEPTIONS = 4;
 
-        private final long delayMillisBound;
         private ArrayDeque<Exception> caughtExceptions;
+        private Iterator<TimeValue> backoffDelayIterator;
 
-        private RetryingListener(long delayMillisBound, ArrayDeque<Exception> caughtExceptions) {
-            this.delayMillisBound = delayMillisBound;
+        private RetryingListener(Iterator<TimeValue> backoffDelayIterator, ArrayDeque<Exception> caughtExceptions) {
             this.caughtExceptions = caughtExceptions;
+            this.backoffDelayIterator = backoffDelayIterator;
         }
 
         @Override
@@ -169,16 +191,13 @@ public void onFailure(Exception e) {
                         () -> new ParameterizedMessage("retryable action timed out after {}", TimeValue.timeValueMillis(elapsedMillis)),
                         e
                     );
-                    onFinalFailure(e);
+                    onFinalFailure(getTimeoutException(e));
                 } else {
                     addException(e);
 
-                    final long nextDelayMillisBound = Math.min(delayMillisBound * 2, Integer.MAX_VALUE);
-                    final RetryingListener retryingListener = new RetryingListener(nextDelayMillisBound, caughtExceptions);
-                    final Runnable runnable = createRunnable(retryingListener);
-                    final long delayMillis = Randomness.get().nextInt(Math.toIntExact(delayMillisBound)) + 1;
+                    final TimeValue delay = backoffDelayIterator.next();
+                    final Runnable runnable = createRunnable(this);
                     if (isDone.get() == false) {
-                        final TimeValue delay = TimeValue.timeValueMillis(delayMillis);
                         logger.debug(() -> new ParameterizedMessage("retrying action that failed in {}", delay), e);
                         try {
                             retryTask = threadPool.schedule(runnable, delay, executor);
diff --git a/server/src/main/java/org/opensearch/action/support/ThreadedActionListener.java b/server/src/main/java/org/opensearch/action/support/ThreadedActionListener.java
index f6a4c87c57344..8b51535ef8d87 100644
--- a/server/src/main/java/org/opensearch/action/support/ThreadedActionListener.java
+++ b/server/src/main/java/org/opensearch/action/support/ThreadedActionListener.java
@@ -34,13 +34,15 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.ThreadPool;
 
 /**
  * An action listener that wraps another action listener and threading its execution.
+ *
+ * @opensearch.internal
  */
 public final class ThreadedActionListener<Response> implements ActionListener<Response> {
     private final Logger logger;
diff --git a/server/src/main/java/org/opensearch/action/support/TimeoutTaskCancellationUtility.java b/server/src/main/java/org/opensearch/action/support/TimeoutTaskCancellationUtility.java
index e132555a3c071..a317a45eab31f 100644
--- a/server/src/main/java/org/opensearch/action/support/TimeoutTaskCancellationUtility.java
+++ b/server/src/main/java/org/opensearch/action/support/TimeoutTaskCancellationUtility.java
@@ -11,15 +11,15 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.client.OriginSettingClient;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.SearchService;
 import org.opensearch.tasks.CancellableTask;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -29,6 +29,11 @@
 import static org.opensearch.action.admin.cluster.node.tasks.get.GetTaskAction.TASKS_ORIGIN;
 import static org.opensearch.action.search.TransportSearchAction.SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING;
 
+/**
+ * Utility to cancel a timeout task
+ *
+ * @opensearch.internal
+ */
 public class TimeoutTaskCancellationUtility {
 
     private static final Logger logger = LogManager.getLogger(TimeoutTaskCancellationUtility.class);
@@ -99,6 +104,8 @@ public static <Response> ActionListener<Response> wrapWithCancellationListener(
      * Timeout listener which executes the provided runnable after timeout is expired and if a response/failure is not yet received.
      * If either a response/failure is received before timeout then the scheduled task is cancelled and response/failure is sent back to
      * the original listener.
+     *
+     * @opensearch.internal
      */
     private static class TimeoutRunnableListener<Response> implements ActionListener<Response>, Runnable {
 
diff --git a/server/src/main/java/org/opensearch/action/support/TransportAction.java b/server/src/main/java/org/opensearch/action/support/TransportAction.java
index 84ece8cfec530..daa11c2d7d80f 100644
--- a/server/src/main/java/org/opensearch/action/support/TransportAction.java
+++ b/server/src/main/java/org/opensearch/action/support/TransportAction.java
@@ -34,20 +34,26 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskCancelledException;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskListener;
 import org.opensearch.tasks.TaskManager;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Base class for a transport action
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportAction<Request extends ActionRequest, Response extends ActionResponse> {
 
     public final String actionName;
@@ -88,31 +94,39 @@ public final Task execute(Request request, ActionListener<Response> listener) {
          */
         final Releasable unregisterChildNode = registerChildNode(request.getParentTask());
         final Task task;
+
         try {
             task = taskManager.register("transport", actionName, request);
         } catch (TaskCancelledException e) {
             unregisterChildNode.close();
             throw e;
         }
-        execute(task, request, new ActionListener<Response>() {
-            @Override
-            public void onResponse(Response response) {
-                try {
-                    Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
-                } finally {
-                    listener.onResponse(response);
+
+        ThreadContext.StoredContext storedContext = taskManager.taskExecutionStarted(task);
+        try {
+            execute(task, request, new ActionListener<Response>() {
+                @Override
+                public void onResponse(Response response) {
+                    try {
+                        Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
+                    } finally {
+                        listener.onResponse(response);
+                    }
                 }
-            }
 
-            @Override
-            public void onFailure(Exception e) {
-                try {
-                    Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
-                } finally {
-                    listener.onFailure(e);
+                @Override
+                public void onFailure(Exception e) {
+                    try {
+                        Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
+                    } finally {
+                        listener.onFailure(e);
+                    }
                 }
-            }
-        });
+            });
+        } finally {
+            storedContext.close();
+        }
+
         return task;
     }
 
@@ -129,25 +143,30 @@ public final Task execute(Request request, TaskListener<Response> listener) {
             unregisterChildNode.close();
             throw e;
         }
-        execute(task, request, new ActionListener<Response>() {
-            @Override
-            public void onResponse(Response response) {
-                try {
-                    Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
-                } finally {
-                    listener.onResponse(task, response);
+        ThreadContext.StoredContext storedContext = taskManager.taskExecutionStarted(task);
+        try {
+            execute(task, request, new ActionListener<Response>() {
+                @Override
+                public void onResponse(Response response) {
+                    try {
+                        Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
+                    } finally {
+                        listener.onResponse(task, response);
+                    }
                 }
-            }
 
-            @Override
-            public void onFailure(Exception e) {
-                try {
-                    Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
-                } finally {
-                    listener.onFailure(task, e);
+                @Override
+                public void onFailure(Exception e) {
+                    try {
+                        Releasables.close(unregisterChildNode, () -> taskManager.unregister(task));
+                    } finally {
+                        listener.onFailure(task, e);
+                    }
                 }
-            }
-        });
+            });
+        } finally {
+            storedContext.close();
+        }
         return task;
     }
 
@@ -171,6 +190,11 @@ public final void execute(Task task, Request request, ActionListener<Response> l
 
     protected abstract void doExecute(Task task, Request request, ActionListener<Response> listener);
 
+    /**
+     * A request filter chain
+     *
+     * @opensearch.internal
+     */
     private static class RequestFilterChain<Request extends ActionRequest, Response extends ActionResponse>
         implements
             ActionFilterChain<Request, Response> {
@@ -205,6 +229,8 @@ public void proceed(Task task, String actionName, Request request, ActionListene
 
     /**
      * Wrapper for an action listener that stores the result at the end of the execution
+     *
+     * @opensearch.internal
      */
     private static class TaskResultStoringActionListener<Response extends ActionResponse> implements ActionListener<Response> {
         private final ActionListener<Response> delegate;
diff --git a/server/src/main/java/org/opensearch/action/support/TransportActions.java b/server/src/main/java/org/opensearch/action/support/TransportActions.java
index d79059d39f407..03e7509b3b8e3 100644
--- a/server/src/main/java/org/opensearch/action/support/TransportActions.java
+++ b/server/src/main/java/org/opensearch/action/support/TransportActions.java
@@ -40,6 +40,11 @@
 import org.opensearch.index.shard.IllegalIndexShardStateException;
 import org.opensearch.index.shard.ShardNotFoundException;
 
+/**
+ * Utility class for transport actions
+ *
+ * @opensearch.internal
+ */
 public class TransportActions {
 
     public static boolean isShardNotAvailableException(final Throwable e) {
diff --git a/server/src/main/java/org/opensearch/action/support/WriteRequest.java b/server/src/main/java/org/opensearch/action/support/WriteRequest.java
index 65737ffedeecb..f462464b99ce8 100644
--- a/server/src/main/java/org/opensearch/action/support/WriteRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/WriteRequest.java
@@ -37,15 +37,17 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
 import org.opensearch.action.update.UpdateRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
 /**
  * Interface implemented by requests that modify the documents in an index like {@link IndexRequest}, {@link UpdateRequest}, and
  * {@link BulkRequest}. Rather than implement this directly most implementers should extend {@link ReplicatedWriteRequest}.
+ *
+ * @opensearch.internal
  */
 public interface WriteRequest<R extends WriteRequest<R>> extends Writeable {
     /**
@@ -73,6 +75,11 @@ default R setRefreshPolicy(String refreshPolicy) {
 
     ActionRequestValidationException validate();
 
+    /**
+     * The refresh policy of the request.
+     *
+     * @opensearch.internal
+     */
     enum RefreshPolicy implements Writeable {
         /**
          * Don't refresh after this request. The default.
diff --git a/server/src/main/java/org/opensearch/action/support/WriteRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/WriteRequestBuilder.java
index c26a08ad6ab60..899d7a8cd65fe 100644
--- a/server/src/main/java/org/opensearch/action/support/WriteRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/WriteRequestBuilder.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
 
+/**
+ * Builder for a write request operations
+ *
+ * @opensearch.internal
+ */
 public interface WriteRequestBuilder<B extends WriteRequestBuilder<B>> {
     WriteRequest<?> request();
 
diff --git a/server/src/main/java/org/opensearch/action/support/WriteResponse.java b/server/src/main/java/org/opensearch/action/support/WriteResponse.java
index 89b04bbdb8362..786f851d88542 100644
--- a/server/src/main/java/org/opensearch/action/support/WriteResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/WriteResponse.java
@@ -42,6 +42,8 @@
 /**
  * Interface implemented by responses for actions that modify the documents in an index like {@link IndexResponse}, {@link UpdateResponse},
  * and {@link BulkResponse}. Rather than implement this directly most implementers should extend {@link DocWriteResponse}.
+ *
+ * @opensearch.internal
  */
 public interface WriteResponse {
     /**
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastOperationRequestBuilder.java
index 2eaa029e687f4..8c756c1682913 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastOperationRequestBuilder.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.support.broadcast;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Request builder for broadcast operations
+ *
+ * @opensearch.internal
+ */
 public abstract class BroadcastOperationRequestBuilder<
     Request extends BroadcastRequest<Request>,
     Response extends BroadcastResponse,
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastRequest.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastRequest.java
index 457f97acbe98b..8a27e032cec5e 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastRequest.java
@@ -36,12 +36,17 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport request for broadcast operations
+ *
+ * @opensearch.internal
+ */
 public class BroadcastRequest<Request extends BroadcastRequest<Request>> extends ActionRequest implements IndicesRequest.Replaceable {
 
     protected String[] indices;
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastResponse.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastResponse.java
index 89dcec7bf75ae..fc0210d3e69b8 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastResponse.java
@@ -32,26 +32,28 @@
 
 package org.opensearch.action.support.broadcast;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.action.RestActions;
 
 import java.io.IOException;
 import java.util.List;
 
-import static org.opensearch.action.support.DefaultShardOperationFailedException.readShardOperationFailed;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.action.support.DefaultShardOperationFailedException.readShardOperationFailed;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Base class for all broadcast operation based responses.
+ *
+ * @opensearch.internal
  */
 public class BroadcastResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardOperationFailedException.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardOperationFailedException.java
index f91de7f3ced7a..03cdb1103343e 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardOperationFailedException.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardOperationFailedException.java
@@ -34,15 +34,15 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * An exception indicating that a failure occurred performing an operation on the shard.
  *
- *
+ * @opensearch.internal
  */
 public class BroadcastShardOperationFailedException extends OpenSearchException implements OpenSearchWrapperException {
 
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardRequest.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardRequest.java
index e89a1437784b9..b426f6e41f81d 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardRequest.java
@@ -35,13 +35,18 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Base class for broadcasting shard requests
+ *
+ * @opensearch.internal
+ */
 public abstract class BroadcastShardRequest extends TransportRequest implements IndicesRequest {
 
     private ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardResponse.java b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardResponse.java
index 96245ec4d91f1..9603f886366f2 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/BroadcastShardResponse.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.action.support.broadcast;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
+/**
+ * Base class for broadcasting response
+ *
+ * @opensearch.internal
+ */
 public abstract class BroadcastShardResponse extends TransportResponse {
 
     ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/TransportBroadcastAction.java b/server/src/main/java/org/opensearch/action/support/broadcast/TransportBroadcastAction.java
index 32dda0af3970d..8bf8555194976 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/TransportBroadcastAction.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/TransportBroadcastAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.support.broadcast;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.support.ActionFilters;
@@ -44,13 +43,15 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.FailAwareWeightedRouting;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportChannel;
@@ -63,6 +64,11 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReferenceArray;
 
+/**
+ * Base transport broadcast action class
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportBroadcastAction<
     Request extends BroadcastRequest<Request>,
     Response extends BroadcastResponse,
@@ -119,6 +125,11 @@ protected void doExecute(Task task, Request request, ActionListener<Response> li
 
     protected abstract ClusterBlockException checkRequestBlock(ClusterState state, Request request, String[] concreteIndices);
 
+    /**
+     * Asynchronous broadcast action
+     *
+     * @opensearch.internal
+     */
     protected class AsyncBroadcastAction {
 
         private final Task task;
@@ -240,7 +251,9 @@ void onOperation(@Nullable ShardRouting shard, final ShardIterator shardIt, int
             // we set the shard failure always, even if its the first in the replication group, and the next one
             // will work (it will just override it...)
             setFailure(shardIt, shardIndex, e);
-            ShardRouting nextShard = shardIt.nextOrNull();
+            ShardRouting nextShard = FailAwareWeightedRouting.getInstance()
+                .findNext(shardIt, clusterService.state(), e, () -> counterOps.incrementAndGet());
+
             if (nextShard != null) {
                 if (e != null) {
                     if (logger.isTraceEnabled()) {
@@ -315,6 +328,11 @@ void setFailure(ShardIterator shardIt, int shardIndex, Exception e) {
         }
     }
 
+    /**
+     * A shard transport handler
+     *
+     * @opensearch.internal
+     */
     class ShardTransportHandler implements TransportRequestHandler<ShardRequest> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeAction.java b/server/src/main/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeAction.java
index 3950f3a9fef77..c08cfb7af0e3d 100644
--- a/server/src/main/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeAction.java
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeAction.java
@@ -33,12 +33,10 @@
 package org.opensearch.action.support.broadcast.node;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.TransportActions;
@@ -53,9 +51,12 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.NodeShouldNotConnectException;
@@ -63,10 +64,9 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
-import org.opensearch.transport.TransportRequestOptions;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -86,6 +86,8 @@
  * @param <Request>              the underlying client request
  * @param <Response>             the response to the client request
  * @param <ShardOperationResult> per-shard operation results
+ *
+ * @opensearch.internal
  */
 public abstract class TransportBroadcastByNodeAction<
     Request extends BroadcastRequest<Request>,
@@ -271,6 +273,11 @@ protected void doExecute(Task task, Request request, ActionListener<Response> li
         new AsyncAction(task, request, listener).start();
     }
 
+    /**
+     * Asynchronous action
+     *
+     * @opensearch.internal
+     */
     protected class AsyncAction {
         private final Task task;
         private final Request request;
@@ -310,9 +317,9 @@ protected AsyncAction(Task task, Request request, ActionListener<Response> liste
             for (ShardRouting shard : shardIt) {
                 // send a request to the shard only if it is assigned to a node that is in the local node's cluster state
                 // a scenario in which a shard can be assigned but to a node that is not in the local node's cluster state
-                // is when the shard is assigned to the master node, the local node has detected the master as failed
-                // and a new master has not yet been elected; in this situation the local node will have removed the
-                // master node from the local cluster state, but the shards assigned to the master will still be in the
+                // is when the shard is assigned to the cluster-manager node, the local node has detected the cluster-manager as failed
+                // and a new cluster-manager has not yet been elected; in this situation the local node will have removed the
+                // cluster-manager node from the local cluster state, but the shards assigned to the cluster-manager will still be in the
                 // routing table as such
                 if (shard.assignedToNode() && nodes.get(shard.currentNodeId()) != null) {
                     String nodeId = shard.currentNodeId();
@@ -441,6 +448,11 @@ protected void onCompletion() {
         }
     }
 
+    /**
+     * Broadcast by a node's transport request handler
+     *
+     * @opensearch.internal
+     */
     class BroadcastByNodeTransportRequestHandler implements TransportRequestHandler<NodeRequest> {
         @Override
         public void messageReceived(final NodeRequest request, TransportChannel channel, Task task) throws Exception {
@@ -520,6 +532,18 @@ private void onShardOperation(
         }
     }
 
+    /**
+     * This method reads ShardRouting from input stream
+     */
+    public List<ShardRouting> getShardRoutingsFromInputStream(StreamInput in) throws IOException {
+        return in.readList(ShardRouting::new);
+    }
+
+    /**
+     * A node request
+     *
+     * @opensearch.internal
+     */
     public class NodeRequest extends TransportRequest implements IndicesRequest {
         private String nodeId;
 
@@ -530,7 +554,7 @@ public class NodeRequest extends TransportRequest implements IndicesRequest {
         public NodeRequest(StreamInput in) throws IOException {
             super(in);
             indicesLevelRequest = readRequestFrom(in);
-            shards = in.readList(ShardRouting::new);
+            shards = getShardRoutingsFromInputStream(in);
             nodeId = in.readString();
         }
 
@@ -567,6 +591,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * A node response
+     *
+     * @opensearch.internal
+     */
     class NodeResponse extends TransportResponse {
         protected String nodeId;
         protected int totalShards;
@@ -631,6 +660,8 @@ public void writeTo(StreamOutput out) throws IOException {
     /**
      * Can be used for implementations of {@link #shardOperation(BroadcastRequest, ShardRouting) shardOperation} for
      * which there is no shard-level return value.
+     *
+     * @opensearch.internal
      */
     public static final class EmptyResult implements Writeable {
         public static EmptyResult INSTANCE = new EmptyResult();
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/node/package-info.java b/server/src/main/java/org/opensearch/action/support/broadcast/node/package-info.java
new file mode 100644
index 0000000000000..1d5ebaf244f77
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/node/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node Level Broadcast transport handlers. */
+package org.opensearch.action.support.broadcast.node;
diff --git a/server/src/main/java/org/opensearch/action/support/broadcast/package-info.java b/server/src/main/java/org/opensearch/action/support/broadcast/package-info.java
new file mode 100644
index 0000000000000..00b5c640fd3a1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/broadcast/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Broadcast info transport handlers. */
+package org.opensearch.action.support.broadcast;
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeOperationRequestBuilder.java
new file mode 100644
index 0000000000000..05c06604725a1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeOperationRequestBuilder.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
+
+/**
+ * Base request builder for cluster-manager node operations
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterManagerNodeOperationRequestBuilder<
+    Request extends ClusterManagerNodeRequest<Request>,
+    Response extends ActionResponse,
+    RequestBuilder extends ClusterManagerNodeOperationRequestBuilder<Request, Response, RequestBuilder>> extends ActionRequestBuilder<
+        Request,
+        Response> {
+
+    protected ClusterManagerNodeOperationRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
+        super(client, action, request);
+    }
+
+    /**
+     * Sets the cluster-manager node timeout in case the cluster-manager has not yet been discovered.
+     */
+    @SuppressWarnings("unchecked")
+    public final RequestBuilder setClusterManagerNodeTimeout(TimeValue timeout) {
+        request.clusterManagerNodeTimeout(timeout);
+        return (RequestBuilder) this;
+    }
+
+    /**
+     * Sets the cluster-manager node timeout in case the cluster-manager has not yet been discovered.
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(TimeValue)}
+     */
+    @SuppressWarnings("unchecked")
+    @Deprecated
+    public final RequestBuilder setMasterNodeTimeout(TimeValue timeout) {
+        return setClusterManagerNodeTimeout(timeout);
+    }
+
+    /**
+     * Sets the cluster-manager node timeout in case the cluster-manager has not yet been discovered.
+     */
+    @SuppressWarnings("unchecked")
+    public final RequestBuilder setClusterManagerNodeTimeout(String timeout) {
+        request.clusterManagerNodeTimeout(timeout);
+        return (RequestBuilder) this;
+    }
+
+    /**
+     * Sets the cluster-manager node timeout in case the cluster-manager has not yet been discovered.
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #setClusterManagerNodeTimeout(String)}
+     */
+    @SuppressWarnings("unchecked")
+    @Deprecated
+    public final RequestBuilder setMasterNodeTimeout(String timeout) {
+        return setClusterManagerNodeTimeout(timeout);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadOperationRequestBuilder.java
new file mode 100644
index 0000000000000..c261f44a0cd04
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadOperationRequestBuilder.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.action.ActionType;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.core.action.ActionResponse;
+
+/**
+ * Base request builder for cluster-manager node read operations that can be executed on the local node as well
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterManagerNodeReadOperationRequestBuilder<
+    Request extends ClusterManagerNodeReadRequest<Request>,
+    Response extends ActionResponse,
+    RequestBuilder extends ClusterManagerNodeReadOperationRequestBuilder<Request, Response, RequestBuilder>> extends
+    ClusterManagerNodeOperationRequestBuilder<Request, Response, RequestBuilder> {
+
+    protected ClusterManagerNodeReadOperationRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
+        super(client, action, request);
+    }
+
+    /**
+     * Specifies if the request should be executed on local node rather than on master
+     */
+    @SuppressWarnings("unchecked")
+    public final RequestBuilder setLocal(boolean local) {
+        request.local(local);
+        return (RequestBuilder) this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadRequest.java b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadRequest.java
new file mode 100644
index 0000000000000..6dcc6ed1b098e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeReadRequest.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Base request for cluster-manager based read operations that allows to read the cluster state from the local node if needed
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterManagerNodeReadRequest<Request extends ClusterManagerNodeReadRequest<Request>> extends
+    ClusterManagerNodeRequest<Request> {
+
+    protected boolean local = false;
+
+    protected ClusterManagerNodeReadRequest() {}
+
+    protected ClusterManagerNodeReadRequest(StreamInput in) throws IOException {
+        super(in);
+        local = in.readBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeBoolean(local);
+    }
+
+    @SuppressWarnings("unchecked")
+    public final Request local(boolean local) {
+        this.local = local;
+        return (Request) this;
+    }
+
+    /**
+     * Return local information, do not retrieve the state from cluster-manager node (default: false).
+     * @return <code>true</code> if local information is to be returned;
+     * <code>false</code> if information is to be retrieved from cluster-manager node (default).
+     */
+    public final boolean local() {
+        return local;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeRequest.java b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeRequest.java
new file mode 100644
index 0000000000000..a43d6fb0b1e7a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/ClusterManagerNodeRequest.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * A based request for cluster-manager based operation.
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterManagerNodeRequest<Request extends ClusterManagerNodeRequest<Request>> extends ActionRequest {
+
+    public static final TimeValue DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT = TimeValue.timeValueSeconds(30);
+
+    /** @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT} */
+    @Deprecated
+    public static final TimeValue DEFAULT_MASTER_NODE_TIMEOUT = DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
+
+    protected TimeValue clusterManagerNodeTimeout = DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
+
+    /** @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout} */
+    @Deprecated
+    protected TimeValue masterNodeTimeout = clusterManagerNodeTimeout;
+
+    protected ClusterManagerNodeRequest() {}
+
+    protected ClusterManagerNodeRequest(StreamInput in) throws IOException {
+        super(in);
+        clusterManagerNodeTimeout = in.readTimeValue();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeTimeValue(clusterManagerNodeTimeout);
+    }
+
+    /**
+     * A timeout value in case the cluster-manager has not been discovered yet or disconnected.
+     */
+    @SuppressWarnings("unchecked")
+    public final Request clusterManagerNodeTimeout(TimeValue timeout) {
+        this.clusterManagerNodeTimeout = timeout;
+        return (Request) this;
+    }
+
+    /**
+     * A timeout value in case the cluster-manager has not been discovered yet or disconnected.
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout(TimeValue)}
+     */
+    @SuppressWarnings("unchecked")
+    @Deprecated
+    public final Request masterNodeTimeout(TimeValue timeout) {
+        return clusterManagerNodeTimeout(timeout);
+    }
+
+    /**
+     * A timeout value in case the cluster-manager has not been discovered yet or disconnected.
+     */
+    public final Request clusterManagerNodeTimeout(String timeout) {
+        return clusterManagerNodeTimeout(
+            TimeValue.parseTimeValue(timeout, null, getClass().getSimpleName() + ".clusterManagerNodeTimeout")
+        );
+    }
+
+    /**
+     * A timeout value in case the cluster-manager has not been discovered yet or disconnected.
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout(String)}
+     */
+    @Deprecated
+    public final Request masterNodeTimeout(String timeout) {
+        return clusterManagerNodeTimeout(timeout);
+    }
+
+    public final TimeValue clusterManagerNodeTimeout() {
+        return this.clusterManagerNodeTimeout;
+    }
+
+    /** @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout()} */
+    @Deprecated
+    public final TimeValue masterNodeTimeout() {
+        return clusterManagerNodeTimeout();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeAction.java b/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeAction.java
new file mode 100644
index 0000000000000..536ddcdd402e2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeAction.java
@@ -0,0 +1,375 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.ActionListenerResponseHandler;
+import org.opensearch.action.ActionRunnable;
+import org.opensearch.action.bulk.BackoffPolicy;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.action.support.RetryableAction;
+import org.opensearch.cluster.ClusterManagerNodeChangePredicate;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateObserver;
+import org.opensearch.cluster.NotClusterManagerException;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.ProcessClusterEventTimeoutException;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
+import org.opensearch.cluster.service.ClusterManagerThrottlingException;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.node.NodeClosedException;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.transport.RemoteTransportException;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.function.Predicate;
+
+/**
+ * A base class for operations that needs to be performed on the cluster-manager node.
+ *
+ * @opensearch.internal
+ */
+public abstract class TransportClusterManagerNodeAction<Request extends ClusterManagerNodeRequest<Request>, Response extends ActionResponse>
+    extends HandledTransportAction<Request, Response> {
+
+    private static final Logger logger = LogManager.getLogger(TransportClusterManagerNodeAction.class);
+
+    protected final ThreadPool threadPool;
+    protected final TransportService transportService;
+    protected final ClusterService clusterService;
+    protected final IndexNameExpressionResolver indexNameExpressionResolver;
+
+    private final String executor;
+
+    protected TransportClusterManagerNodeAction(
+        String actionName,
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        Writeable.Reader<Request> request,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        this(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
+    }
+
+    protected TransportClusterManagerNodeAction(
+        String actionName,
+        boolean canTripCircuitBreaker,
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        Writeable.Reader<Request> request,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(actionName, canTripCircuitBreaker, transportService, actionFilters, request);
+        this.transportService = transportService;
+        this.clusterService = clusterService;
+        this.threadPool = threadPool;
+        this.indexNameExpressionResolver = indexNameExpressionResolver;
+        this.executor = executor();
+    }
+
+    protected abstract String executor();
+
+    protected abstract Response read(StreamInput in) throws IOException;
+
+    /**
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerOperation(ClusterManagerNodeRequest, ClusterState, ActionListener)}
+     */
+    @Deprecated
+    protected void masterOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
+        throw new UnsupportedOperationException("Must be overridden");
+    }
+
+    // TODO: Add abstract keyword after removing the deprecated masterOperation()
+    protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
+        masterOperation(request, state, listener);
+    }
+
+    /**
+     * Override this operation if access to the task parameter is needed
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerOperation(Task, ClusterManagerNodeRequest, ClusterState, ActionListener)}
+     */
+    @Deprecated
+    protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
+        clusterManagerOperation(request, state, listener);
+    }
+
+    /**
+     * Override this operation if access to the task parameter is needed
+     */
+    // TODO: Change the implementation to call 'clusterManagerOperation(request...)' after removing the deprecated masterOperation()
+    protected void clusterManagerOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener)
+        throws Exception {
+        masterOperation(task, request, state, listener);
+    }
+
+    protected boolean localExecute(Request request) {
+        return false;
+    }
+
+    protected abstract ClusterBlockException checkBlock(Request request, ClusterState state);
+
+    @Override
+    protected void doExecute(Task task, final Request request, ActionListener<Response> listener) {
+        if (task != null) {
+            request.setParentTask(clusterService.localNode().getId(), task.getId());
+        }
+        new AsyncSingleAction(task, request, listener).run();
+    }
+
+    /**
+     * Asynchronous single action
+     *
+     * @opensearch.internal
+     */
+    class AsyncSingleAction extends RetryableAction {
+
+        private ActionListener<Response> listener;
+        private final Request request;
+        private ClusterStateObserver observer;
+        private final long startTime;
+        private final Task task;
+
+        AsyncSingleAction(Task task, Request request, ActionListener<Response> listener) {
+            super(
+                logger,
+                threadPool,
+                ClusterManagerTaskThrottler.getBaseDelayForRetry(),
+                request.clusterManagerNodeTimeout,
+                listener,
+                BackoffPolicy.exponentialEqualJitterBackoff(
+                    ClusterManagerTaskThrottler.getBaseDelayForRetry().millis(),
+                    ClusterManagerTaskThrottler.getMaxDelayForRetry().millis()
+                ),
+                ThreadPool.Names.SAME
+            );
+            this.task = task;
+            this.request = request;
+            this.startTime = threadPool.relativeTimeInMillis();
+        }
+
+        @Override
+        public void tryAction(ActionListener retryListener) {
+            ClusterState state = clusterService.state();
+            logger.trace("starting processing request [{}] with cluster state version [{}]", request, state.version());
+            this.listener = retryListener;
+            doStart(state);
+        }
+
+        @Override
+        public boolean shouldRetry(Exception e) {
+            // If remote address is null, i.e request is generated from same node and we would want to perform retry for it
+            // If remote address is not null, i.e request is generated from remote node and received on this master node on transport layer
+            // in that case we would want throttling retry to perform on remote node only not on this master node.
+            if (request.remoteAddress() == null) {
+                if (e instanceof TransportException) {
+                    return ((TransportException) e).unwrapCause() instanceof ClusterManagerThrottlingException;
+                }
+                return e instanceof ClusterManagerThrottlingException;
+            }
+            return false;
+        }
+
+        /**
+         * If tasks gets timed out in retrying on throttling,
+         * it should send cluster event timeout exception.
+         */
+        @Override
+        public Exception getTimeoutException(Exception e) {
+            return new ProcessClusterEventTimeoutException(request.masterNodeTimeout, actionName);
+        }
+
+        protected void doStart(ClusterState clusterState) {
+            try {
+                final DiscoveryNodes nodes = clusterState.nodes();
+                if (nodes.isLocalNodeElectedClusterManager() || localExecute(request)) {
+                    // check for block, if blocked, retry, else, execute locally
+                    final ClusterBlockException blockException = checkBlock(request, clusterState);
+                    if (blockException != null) {
+                        if (!blockException.retryable()) {
+                            listener.onFailure(blockException);
+                        } else {
+                            logger.debug("can't execute due to a cluster block, retrying", blockException);
+                            retry(clusterState, blockException, newState -> {
+                                try {
+                                    ClusterBlockException newException = checkBlock(request, newState);
+                                    return (newException == null || !newException.retryable());
+                                } catch (Exception e) {
+                                    // accept state as block will be rechecked by doStart() and listener.onFailure() then called
+                                    logger.trace("exception occurred during cluster block checking, accepting state", e);
+                                    return true;
+                                }
+                            });
+                        }
+                    } else {
+                        ActionListener<Response> delegate = ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
+                            if (t instanceof FailedToCommitClusterStateException || t instanceof NotClusterManagerException) {
+                                logger.debug(
+                                    () -> new ParameterizedMessage(
+                                        "master could not publish cluster state or "
+                                            + "stepped down before publishing action [{}], scheduling a retry",
+                                        actionName
+                                    ),
+                                    t
+                                );
+                                retryOnMasterChange(clusterState, t);
+                            } else {
+                                delegatedListener.onFailure(t);
+                            }
+                        });
+                        threadPool.executor(executor)
+                            .execute(ActionRunnable.wrap(delegate, l -> clusterManagerOperation(task, request, clusterState, l)));
+                    }
+                } else {
+                    if (nodes.getClusterManagerNode() == null) {
+                        logger.debug("no known cluster-manager node, scheduling a retry");
+                        retryOnMasterChange(clusterState, null);
+                    } else {
+                        DiscoveryNode clusterManagerNode = nodes.getClusterManagerNode();
+                        final String actionName = getClusterManagerActionName(clusterManagerNode);
+                        transportService.sendRequest(
+                            clusterManagerNode,
+                            actionName,
+                            request,
+                            new ActionListenerResponseHandler<Response>(listener, TransportClusterManagerNodeAction.this::read) {
+                                @Override
+                                public void handleException(final TransportException exp) {
+                                    Throwable cause = exp.unwrapCause();
+                                    if (cause instanceof ConnectTransportException
+                                        || (exp instanceof RemoteTransportException && cause instanceof NodeClosedException)) {
+                                        // we want to retry here a bit to see if a new cluster-manager is elected
+                                        logger.debug(
+                                            "connection exception while trying to forward request with action name [{}] to "
+                                                + "master node [{}], scheduling a retry. Error: [{}]",
+                                            actionName,
+                                            nodes.getClusterManagerNode(),
+                                            exp.getDetailedMessage()
+                                        );
+                                        retryOnMasterChange(clusterState, cause);
+                                    } else {
+                                        listener.onFailure(exp);
+                                    }
+                                }
+                            }
+                        );
+                    }
+                }
+            } catch (Exception e) {
+                listener.onFailure(e);
+            }
+        }
+
+        private void retryOnMasterChange(ClusterState state, Throwable failure) {
+            retry(state, failure, ClusterManagerNodeChangePredicate.build(state));
+        }
+
+        private void retry(ClusterState state, final Throwable failure, final Predicate<ClusterState> statePredicate) {
+            if (observer == null) {
+                final long remainingTimeoutMS = request.clusterManagerNodeTimeout().millis() - (threadPool.relativeTimeInMillis()
+                    - startTime);
+                if (remainingTimeoutMS <= 0) {
+                    logger.debug(() -> new ParameterizedMessage("timed out before retrying [{}] after failure", actionName), failure);
+                    listener.onFailure(new ClusterManagerNotDiscoveredException(failure));
+                    return;
+                }
+                this.observer = new ClusterStateObserver(
+                    state,
+                    clusterService,
+                    TimeValue.timeValueMillis(remainingTimeoutMS),
+                    logger,
+                    threadPool.getThreadContext()
+                );
+            }
+            observer.waitForNextChange(new ClusterStateObserver.Listener() {
+                @Override
+                public void onNewClusterState(ClusterState state) {
+                    doStart(state);
+                }
+
+                @Override
+                public void onClusterServiceClose() {
+                    listener.onFailure(new NodeClosedException(clusterService.localNode()));
+                }
+
+                @Override
+                public void onTimeout(TimeValue timeout) {
+                    logger.debug(
+                        () -> new ParameterizedMessage("timed out while retrying [{}] after failure (timeout [{}])", actionName, timeout),
+                        failure
+                    );
+                    listener.onFailure(new ClusterManagerNotDiscoveredException(failure));
+                }
+            }, statePredicate);
+        }
+    }
+
+    /**
+     * Allows to conditionally return a different cluster-manager node action name in the case an action gets renamed.
+     * This mainly for backwards compatibility should be used rarely
+     */
+    protected String getClusterManagerActionName(DiscoveryNode node) {
+        return actionName;
+    }
+
+    /**
+     * Allows to conditionally return a different cluster-manager node action name in the case an action gets renamed.
+     * This mainly for backwards compatibility should be used rarely
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #getClusterManagerActionName(DiscoveryNode)}
+     */
+    @Deprecated
+    protected String getMasterActionName(DiscoveryNode node) {
+        return getClusterManagerActionName(node);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeReadAction.java b/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeReadAction.java
new file mode 100644
index 0000000000000..d8cd5af992028
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeReadAction.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+/**
+ * A base class for read operations that needs to be performed on the cluster-manager node.
+ * Can also be executed on the local node if needed.
+ *
+ * @opensearch.internal
+ */
+public abstract class TransportClusterManagerNodeReadAction<
+    Request extends ClusterManagerNodeReadRequest<Request>,
+    Response extends ActionResponse> extends TransportClusterManagerNodeAction<Request, Response> {
+
+    protected TransportClusterManagerNodeReadAction(
+        String actionName,
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        Writeable.Reader<Request> request,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        this(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
+    }
+
+    protected TransportClusterManagerNodeReadAction(
+        String actionName,
+        boolean checkSizeLimit,
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        Writeable.Reader<Request> request,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(
+            actionName,
+            checkSizeLimit,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            request,
+            indexNameExpressionResolver
+        );
+    }
+
+    @Override
+    protected final boolean localExecute(Request request) {
+        return request.local();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequest.java b/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequest.java
new file mode 100644
index 0000000000000..5b7da57705ac3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequest.java
@@ -0,0 +1,106 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager.info;
+
+import org.opensearch.Version;
+import org.opensearch.action.IndicesRequest;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Transport request for cluster information
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterInfoRequest<Request extends ClusterInfoRequest<Request>> extends ClusterManagerNodeReadRequest<Request>
+    implements
+        IndicesRequest.Replaceable {
+
+    private String[] indices = Strings.EMPTY_ARRAY;
+
+    private IndicesOptions indicesOptions = IndicesOptions.strictExpandOpen();
+
+    public ClusterInfoRequest() {}
+
+    public ClusterInfoRequest(StreamInput in) throws IOException {
+        super(in);
+        indices = in.readStringArray();
+        if (in.getVersion().before(Version.V_2_0_0)) {
+            in.readStringArray();
+        }
+        indicesOptions = IndicesOptions.readIndicesOptions(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeStringArray(indices);
+        if (out.getVersion().before(Version.V_2_0_0)) {
+            out.writeStringArray(Strings.EMPTY_ARRAY);
+        }
+        indicesOptions.writeIndicesOptions(out);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public Request indices(String... indices) {
+        this.indices = indices;
+        return (Request) this;
+    }
+
+    @SuppressWarnings("unchecked")
+    public Request indicesOptions(IndicesOptions indicesOptions) {
+        this.indicesOptions = indicesOptions;
+        return (Request) this;
+    }
+
+    @Override
+    public String[] indices() {
+        return indices;
+    }
+
+    @Override
+    public IndicesOptions indicesOptions() {
+        return indicesOptions;
+    }
+
+    @Override
+    public boolean includeDataStreams() {
+        return true;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequestBuilder.java
new file mode 100644
index 0000000000000..f22ff60b83a58
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/info/ClusterInfoRequestBuilder.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager.info;
+
+import org.opensearch.action.ActionType;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
+import org.opensearch.client.OpenSearchClient;
+import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.action.ActionResponse;
+
+/**
+ * Transport request builder for cluster information
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterInfoRequestBuilder<
+    Request extends ClusterInfoRequest<Request>,
+    Response extends ActionResponse,
+    Builder extends ClusterInfoRequestBuilder<Request, Response, Builder>> extends ClusterManagerNodeReadOperationRequestBuilder<
+        Request,
+        Response,
+        Builder> {
+
+    protected ClusterInfoRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
+        super(client, action, request);
+    }
+
+    @SuppressWarnings("unchecked")
+    public Builder setIndices(String... indices) {
+        request.indices(indices);
+        return (Builder) this;
+    }
+
+    @SuppressWarnings("unchecked")
+    public Builder addIndices(String... indices) {
+        request.indices(ArrayUtils.concat(request.indices(), indices));
+        return (Builder) this;
+    }
+
+    @SuppressWarnings("unchecked")
+    public Builder setIndicesOptions(IndicesOptions indicesOptions) {
+        request.indicesOptions(indicesOptions);
+        return (Builder) this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/info/TransportClusterInfoAction.java b/server/src/main/java/org/opensearch/action/support/clustermanager/info/TransportClusterInfoAction.java
new file mode 100644
index 0000000000000..65f00a4731ab5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/info/TransportClusterInfoAction.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager.info;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+/**
+ * Perform cluster information action
+ *
+ * @opensearch.internal
+ */
+public abstract class TransportClusterInfoAction<Request extends ClusterInfoRequest<Request>, Response extends ActionResponse> extends
+    TransportClusterManagerNodeReadAction<Request, Response> {
+
+    public TransportClusterInfoAction(
+        String actionName,
+        TransportService transportService,
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        ActionFilters actionFilters,
+        Writeable.Reader<Request> request,
+        IndexNameExpressionResolver indexNameExpressionResolver
+    ) {
+        super(actionName, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
+    }
+
+    @Override
+    protected String executor() {
+        // read operation, lightweight...
+        return ThreadPool.Names.SAME;
+    }
+
+    @Override
+    protected ClusterBlockException checkBlock(Request request, ClusterState state) {
+        return state.blocks()
+            .indicesBlockedException(ClusterBlockLevel.METADATA_READ, indexNameExpressionResolver.concreteIndexNames(state, request));
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerOperation(ClusterInfoRequest, ClusterState, ActionListener)} */
+    @Deprecated
+    protected final void masterOperation(final Request request, final ClusterState state, final ActionListener<Response> listener) {
+        clusterManagerOperation(request, state, listener);
+    }
+
+    @Override
+    protected final void clusterManagerOperation(final Request request, final ClusterState state, final ActionListener<Response> listener) {
+        String[] concreteIndices = indexNameExpressionResolver.concreteIndexNames(state, request);
+        doClusterManagerOperation(request, concreteIndices, state, listener);
+    }
+
+    // TODO: Add abstract keyword after removing the deprecated doMasterOperation()
+    protected void doClusterManagerOperation(
+        Request request,
+        String[] concreteIndices,
+        ClusterState state,
+        ActionListener<Response> listener
+    ) {
+        doMasterOperation(request, concreteIndices, state, listener);
+    }
+
+    /**
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #doClusterManagerOperation(ClusterInfoRequest, String[], ClusterState, ActionListener)}
+     */
+    @Deprecated
+    protected void doMasterOperation(Request request, String[] concreteIndices, ClusterState state, ActionListener<Response> listener) {
+        throw new UnsupportedOperationException("Must be overridden");
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/info/package-info.java b/server/src/main/java/org/opensearch/action/support/clustermanager/info/package-info.java
new file mode 100644
index 0000000000000..7f21d5d22ec2e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/info/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Manager Node Information transport handlers. */
+package org.opensearch.action.support.clustermanager.info;
diff --git a/server/src/main/java/org/opensearch/action/support/clustermanager/package-info.java b/server/src/main/java/org/opensearch/action/support/clustermanager/package-info.java
new file mode 100644
index 0000000000000..13d604ed71e3d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/clustermanager/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Manager Node transport handlers. */
+package org.opensearch.action.support.clustermanager;
diff --git a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequest.java b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequest.java
index 278c4f287b4f5..59f238a202788 100644
--- a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequest.java
@@ -32,23 +32,27 @@
 package org.opensearch.action.support.master;
 
 import org.opensearch.cluster.ack.AckedRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+import static org.opensearch.common.unit.TimeValue.timeValueHours;
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 
 /**
  * Abstract class that allows to mark action requests that support acknowledgements.
  * Facilitates consistency across different api.
+ *
+ * @opensearch.internal
  */
 public abstract class AcknowledgedRequest<Request extends MasterNodeRequest<Request>> extends MasterNodeRequest<Request>
     implements
         AckedRequest {
 
     public static final TimeValue DEFAULT_ACK_TIMEOUT = timeValueSeconds(30);
+    public static final TimeValue DEFAULT_TASK_EXECUTION_TIMEOUT = timeValueHours(1);
 
     protected TimeValue timeout = DEFAULT_ACK_TIMEOUT;
 
diff --git a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequestBuilder.java
index 9337e646cebea..7a0824c6d30ca 100644
--- a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedRequestBuilder.java
@@ -36,7 +36,9 @@
 import org.opensearch.common.unit.TimeValue;
 
 /**
- * Base request builder for master node operations that support acknowledgements
+ * Base request builder for cluster-manager node operations that support acknowledgements
+ *
+ * @opensearch.internal
  */
 public abstract class AcknowledgedRequestBuilder<
     Request extends AcknowledgedRequest<Request>,
diff --git a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedResponse.java b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedResponse.java
index dca3096b99440..5d09d880336f1 100644
--- a/server/src/main/java/org/opensearch/action/support/master/AcknowledgedResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/master/AcknowledgedResponse.java
@@ -31,23 +31,25 @@
 
 package org.opensearch.action.support.master;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A response that indicates that a request has been acknowledged
+ *
+ * @opensearch.internal
  */
 public class AcknowledgedResponse extends ActionResponse implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/action/support/master/MasterNodeOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/master/MasterNodeOperationRequestBuilder.java
index b39ec5fe4cc6b..0acbd998a6322 100644
--- a/server/src/main/java/org/opensearch/action/support/master/MasterNodeOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/master/MasterNodeOperationRequestBuilder.java
@@ -33,41 +33,24 @@
 package org.opensearch.action.support.master;
 
 import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
 
 /**
- * Base request builder for master node operations
+ * Base request builder for cluster-manager node operations
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link ClusterManagerNodeOperationRequestBuilder}
  */
+@Deprecated
 public abstract class MasterNodeOperationRequestBuilder<
     Request extends MasterNodeRequest<Request>,
     Response extends ActionResponse,
-    RequestBuilder extends MasterNodeOperationRequestBuilder<Request, Response, RequestBuilder>> extends ActionRequestBuilder<
-        Request,
-        Response> {
+    RequestBuilder extends MasterNodeOperationRequestBuilder<Request, Response, RequestBuilder>> extends
+    ClusterManagerNodeOperationRequestBuilder<Request, Response, RequestBuilder> {
 
     protected MasterNodeOperationRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
         super(client, action, request);
     }
-
-    /**
-     * Sets the master node timeout in case the master has not yet been discovered.
-     */
-    @SuppressWarnings("unchecked")
-    public final RequestBuilder setMasterNodeTimeout(TimeValue timeout) {
-        request.masterNodeTimeout(timeout);
-        return (RequestBuilder) this;
-    }
-
-    /**
-     * Sets the master node timeout in case the master has not yet been discovered.
-     */
-    @SuppressWarnings("unchecked")
-    public final RequestBuilder setMasterNodeTimeout(String timeout) {
-        request.masterNodeTimeout(timeout);
-        return (RequestBuilder) this;
-    }
-
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadOperationRequestBuilder.java
index add5c5177df42..36a3fc1d2de73 100644
--- a/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadOperationRequestBuilder.java
@@ -33,28 +33,24 @@
 package org.opensearch.action.support.master;
 
 import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
+import org.opensearch.core.action.ActionResponse;
 
 /**
- * Base request builder for master node read operations that can be executed on the local node as well
+ * Base request builder for cluster-manager node read operations that can be executed on the local node as well
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link ClusterManagerNodeReadOperationRequestBuilder}
  */
+@Deprecated
 public abstract class MasterNodeReadOperationRequestBuilder<
     Request extends MasterNodeReadRequest<Request>,
     Response extends ActionResponse,
     RequestBuilder extends MasterNodeReadOperationRequestBuilder<Request, Response, RequestBuilder>> extends
-    MasterNodeOperationRequestBuilder<Request, Response, RequestBuilder> {
+    ClusterManagerNodeReadOperationRequestBuilder<Request, Response, RequestBuilder> {
 
     protected MasterNodeReadOperationRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
         super(client, action, request);
     }
-
-    /**
-     * Specifies if the request should be executed on local node rather than on master
-     */
-    @SuppressWarnings("unchecked")
-    public final RequestBuilder setLocal(boolean local) {
-        request.local(local);
-        return (RequestBuilder) this;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadRequest.java b/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadRequest.java
index eeafa148ca7c3..ea8f6a6e43cfe 100644
--- a/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/master/MasterNodeReadRequest.java
@@ -32,43 +32,22 @@
 
 package org.opensearch.action.support.master;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeReadRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
- * Base request for master based read operations that allows to read the cluster state from the local node if needed
+ * Base request for cluster-manager based read operations that allows to read the cluster state from the local node if needed
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link ClusterManagerNodeReadRequest}
  */
-public abstract class MasterNodeReadRequest<Request extends MasterNodeReadRequest<Request>> extends MasterNodeRequest<Request> {
-
-    protected boolean local = false;
-
+@Deprecated
+public abstract class MasterNodeReadRequest<Request extends MasterNodeReadRequest<Request>> extends ClusterManagerNodeReadRequest<Request> {
     protected MasterNodeReadRequest() {}
 
     protected MasterNodeReadRequest(StreamInput in) throws IOException {
         super(in);
-        local = in.readBoolean();
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        out.writeBoolean(local);
-    }
-
-    @SuppressWarnings("unchecked")
-    public final Request local(boolean local) {
-        this.local = local;
-        return (Request) this;
-    }
-
-    /**
-     * Return local information, do not retrieve the state from master node (default: false).
-     * @return <code>true</code> if local information is to be returned;
-     * <code>false</code> if information is to be retrieved from master node (default).
-     */
-    public final boolean local() {
-        return local;
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/MasterNodeRequest.java b/server/src/main/java/org/opensearch/action/support/master/MasterNodeRequest.java
index d5be6c48e23b8..cfab63a845f7f 100644
--- a/server/src/main/java/org/opensearch/action/support/master/MasterNodeRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/master/MasterNodeRequest.java
@@ -32,52 +32,23 @@
 
 package org.opensearch.action.support.master;
 
-import org.opensearch.action.ActionRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.TimeValue;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
- * A based request for master based operation.
+ * A based request for cluster-manager based operation.
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link ClusterManagerNodeRequest}
  */
-public abstract class MasterNodeRequest<Request extends MasterNodeRequest<Request>> extends ActionRequest {
-
-    public static final TimeValue DEFAULT_MASTER_NODE_TIMEOUT = TimeValue.timeValueSeconds(30);
-
-    protected TimeValue masterNodeTimeout = DEFAULT_MASTER_NODE_TIMEOUT;
+@Deprecated
+public abstract class MasterNodeRequest<Request extends MasterNodeRequest<Request>> extends ClusterManagerNodeRequest<Request> {
 
     protected MasterNodeRequest() {}
 
     protected MasterNodeRequest(StreamInput in) throws IOException {
         super(in);
-        masterNodeTimeout = in.readTimeValue();
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        out.writeTimeValue(masterNodeTimeout);
-    }
-
-    /**
-     * A timeout value in case the master has not been discovered yet or disconnected.
-     */
-    @SuppressWarnings("unchecked")
-    public final Request masterNodeTimeout(TimeValue timeout) {
-        this.masterNodeTimeout = timeout;
-        return (Request) this;
-    }
-
-    /**
-     * A timeout value in case the master has not been discovered yet or disconnected.
-     */
-    public final Request masterNodeTimeout(String timeout) {
-        return masterNodeTimeout(TimeValue.parseTimeValue(timeout, null, getClass().getSimpleName() + ".masterNodeTimeout"));
-    }
-
-    public final TimeValue masterNodeTimeout() {
-        return this.masterNodeTimeout;
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/ShardsAcknowledgedResponse.java b/server/src/main/java/org/opensearch/action/support/master/ShardsAcknowledgedResponse.java
index 5964867d2d618..fd54e810528d3 100644
--- a/server/src/main/java/org/opensearch/action/support/master/ShardsAcknowledgedResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/master/ShardsAcknowledgedResponse.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.action.support.master;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Transport response for shard acknowledgements
+ *
+ * @opensearch.internal
+ */
 public abstract class ShardsAcknowledgedResponse extends AcknowledgedResponse {
 
     protected static final ParseField SHARDS_ACKNOWLEDGED = new ParseField("shards_acknowledged");
diff --git a/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeAction.java b/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeAction.java
index 62d08c23534af..eec7965bfed02 100644
--- a/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeAction.java
+++ b/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeAction.java
@@ -32,54 +32,24 @@
 
 package org.opensearch.action.support.master;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionListenerResponseHandler;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.HandledTransportAction;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.ClusterStateObserver;
-import org.opensearch.cluster.MasterNodeChangePredicate;
-import org.opensearch.cluster.NotMasterException;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.discovery.MasterNotDiscoveredException;
-import org.opensearch.node.NodeClosedException;
-import org.opensearch.tasks.Task;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.ConnectTransportException;
-import org.opensearch.transport.RemoteTransportException;
-import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportService;
 
-import java.io.IOException;
-import java.util.function.Predicate;
-
 /**
- * A base class for operations that needs to be performed on the master node.
+ * A base class for operations that needs to be performed on the cluster-manager node.
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link TransportClusterManagerNodeAction}
  */
+@Deprecated
 public abstract class TransportMasterNodeAction<Request extends MasterNodeRequest<Request>, Response extends ActionResponse> extends
-    HandledTransportAction<Request, Response> {
-
-    private static final Logger logger = LogManager.getLogger(TransportMasterNodeAction.class);
-
-    protected final ThreadPool threadPool;
-    protected final TransportService transportService;
-    protected final ClusterService clusterService;
-    protected final IndexNameExpressionResolver indexNameExpressionResolver;
-
-    private final String executor;
+    TransportClusterManagerNodeAction<Request, Response> {
 
     protected TransportMasterNodeAction(
         String actionName,
@@ -90,7 +60,7 @@ protected TransportMasterNodeAction(
         Writeable.Reader<Request> request,
         IndexNameExpressionResolver indexNameExpressionResolver
     ) {
-        this(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
+        super(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
     }
 
     protected TransportMasterNodeAction(
@@ -103,186 +73,16 @@ protected TransportMasterNodeAction(
         Writeable.Reader<Request> request,
         IndexNameExpressionResolver indexNameExpressionResolver
     ) {
-        super(actionName, canTripCircuitBreaker, transportService, actionFilters, request);
-        this.transportService = transportService;
-        this.clusterService = clusterService;
-        this.threadPool = threadPool;
-        this.indexNameExpressionResolver = indexNameExpressionResolver;
-        this.executor = executor();
+        super(
+            actionName,
+            canTripCircuitBreaker,
+            transportService,
+            clusterService,
+            threadPool,
+            actionFilters,
+            request,
+            indexNameExpressionResolver
+        );
     }
 
-    protected abstract String executor();
-
-    protected abstract Response read(StreamInput in) throws IOException;
-
-    protected abstract void masterOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception;
-
-    /**
-     * Override this operation if access to the task parameter is needed
-     */
-    protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
-        masterOperation(request, state, listener);
-    }
-
-    protected boolean localExecute(Request request) {
-        return false;
-    }
-
-    protected abstract ClusterBlockException checkBlock(Request request, ClusterState state);
-
-    @Override
-    protected void doExecute(Task task, final Request request, ActionListener<Response> listener) {
-        ClusterState state = clusterService.state();
-        logger.trace("starting processing request [{}] with cluster state version [{}]", request, state.version());
-        if (task != null) {
-            request.setParentTask(clusterService.localNode().getId(), task.getId());
-        }
-        new AsyncSingleAction(task, request, listener).doStart(state);
-    }
-
-    class AsyncSingleAction {
-
-        private final ActionListener<Response> listener;
-        private final Request request;
-        private ClusterStateObserver observer;
-        private final long startTime;
-        private final Task task;
-
-        AsyncSingleAction(Task task, Request request, ActionListener<Response> listener) {
-            this.task = task;
-            this.request = request;
-            this.listener = listener;
-            this.startTime = threadPool.relativeTimeInMillis();
-        }
-
-        protected void doStart(ClusterState clusterState) {
-            try {
-                final DiscoveryNodes nodes = clusterState.nodes();
-                if (nodes.isLocalNodeElectedMaster() || localExecute(request)) {
-                    // check for block, if blocked, retry, else, execute locally
-                    final ClusterBlockException blockException = checkBlock(request, clusterState);
-                    if (blockException != null) {
-                        if (!blockException.retryable()) {
-                            listener.onFailure(blockException);
-                        } else {
-                            logger.debug("can't execute due to a cluster block, retrying", blockException);
-                            retry(clusterState, blockException, newState -> {
-                                try {
-                                    ClusterBlockException newException = checkBlock(request, newState);
-                                    return (newException == null || !newException.retryable());
-                                } catch (Exception e) {
-                                    // accept state as block will be rechecked by doStart() and listener.onFailure() then called
-                                    logger.trace("exception occurred during cluster block checking, accepting state", e);
-                                    return true;
-                                }
-                            });
-                        }
-                    } else {
-                        ActionListener<Response> delegate = ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
-                            if (t instanceof FailedToCommitClusterStateException || t instanceof NotMasterException) {
-                                logger.debug(
-                                    () -> new ParameterizedMessage(
-                                        "master could not publish cluster state or "
-                                            + "stepped down before publishing action [{}], scheduling a retry",
-                                        actionName
-                                    ),
-                                    t
-                                );
-                                retryOnMasterChange(clusterState, t);
-                            } else {
-                                delegatedListener.onFailure(t);
-                            }
-                        });
-                        threadPool.executor(executor)
-                            .execute(ActionRunnable.wrap(delegate, l -> masterOperation(task, request, clusterState, l)));
-                    }
-                } else {
-                    if (nodes.getMasterNode() == null) {
-                        logger.debug("no known master node, scheduling a retry");
-                        retryOnMasterChange(clusterState, null);
-                    } else {
-                        DiscoveryNode masterNode = nodes.getMasterNode();
-                        final String actionName = getMasterActionName(masterNode);
-                        transportService.sendRequest(
-                            masterNode,
-                            actionName,
-                            request,
-                            new ActionListenerResponseHandler<Response>(listener, TransportMasterNodeAction.this::read) {
-                                @Override
-                                public void handleException(final TransportException exp) {
-                                    Throwable cause = exp.unwrapCause();
-                                    if (cause instanceof ConnectTransportException
-                                        || (exp instanceof RemoteTransportException && cause instanceof NodeClosedException)) {
-                                        // we want to retry here a bit to see if a new master is elected
-                                        logger.debug(
-                                            "connection exception while trying to forward request with action name [{}] to "
-                                                + "master node [{}], scheduling a retry. Error: [{}]",
-                                            actionName,
-                                            nodes.getMasterNode(),
-                                            exp.getDetailedMessage()
-                                        );
-                                        retryOnMasterChange(clusterState, cause);
-                                    } else {
-                                        listener.onFailure(exp);
-                                    }
-                                }
-                            }
-                        );
-                    }
-                }
-            } catch (Exception e) {
-                listener.onFailure(e);
-            }
-        }
-
-        private void retryOnMasterChange(ClusterState state, Throwable failure) {
-            retry(state, failure, MasterNodeChangePredicate.build(state));
-        }
-
-        private void retry(ClusterState state, final Throwable failure, final Predicate<ClusterState> statePredicate) {
-            if (observer == null) {
-                final long remainingTimeoutMS = request.masterNodeTimeout().millis() - (threadPool.relativeTimeInMillis() - startTime);
-                if (remainingTimeoutMS <= 0) {
-                    logger.debug(() -> new ParameterizedMessage("timed out before retrying [{}] after failure", actionName), failure);
-                    listener.onFailure(new MasterNotDiscoveredException(failure));
-                    return;
-                }
-                this.observer = new ClusterStateObserver(
-                    state,
-                    clusterService,
-                    TimeValue.timeValueMillis(remainingTimeoutMS),
-                    logger,
-                    threadPool.getThreadContext()
-                );
-            }
-            observer.waitForNextChange(new ClusterStateObserver.Listener() {
-                @Override
-                public void onNewClusterState(ClusterState state) {
-                    doStart(state);
-                }
-
-                @Override
-                public void onClusterServiceClose() {
-                    listener.onFailure(new NodeClosedException(clusterService.localNode()));
-                }
-
-                @Override
-                public void onTimeout(TimeValue timeout) {
-                    logger.debug(
-                        () -> new ParameterizedMessage("timed out while retrying [{}] after failure (timeout [{}])", actionName, timeout),
-                        failure
-                    );
-                    listener.onFailure(new MasterNotDiscoveredException(failure));
-                }
-            }, statePredicate);
-        }
-    }
-
-    /**
-     * Allows to conditionally return a different master node action name in the case an action gets renamed.
-     * This mainly for backwards compatibility should be used rarely
-     */
-    protected String getMasterActionName(DiscoveryNode node) {
-        return actionName;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeReadAction.java b/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeReadAction.java
index b230901eb456e..b95459971737f 100644
--- a/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeReadAction.java
+++ b/server/src/main/java/org/opensearch/action/support/master/TransportMasterNodeReadAction.java
@@ -32,20 +32,25 @@
 
 package org.opensearch.action.support.master;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeReadAction;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 /**
- * A base class for read operations that needs to be performed on the master node.
+ * A base class for read operations that needs to be performed on the cluster-manager node.
  * Can also be executed on the local node if needed.
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link TransportClusterManagerNodeReadAction}
  */
+@Deprecated
 public abstract class TransportMasterNodeReadAction<Request extends MasterNodeReadRequest<Request>, Response extends ActionResponse> extends
-    TransportMasterNodeAction<Request, Response> {
+    TransportClusterManagerNodeReadAction<Request, Response> {
 
     protected TransportMasterNodeReadAction(
         String actionName,
@@ -56,7 +61,7 @@ protected TransportMasterNodeReadAction(
         Writeable.Reader<Request> request,
         IndexNameExpressionResolver indexNameExpressionResolver
     ) {
-        this(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
+        super(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
     }
 
     protected TransportMasterNodeReadAction(
@@ -81,8 +86,4 @@ protected TransportMasterNodeReadAction(
         );
     }
 
-    @Override
-    protected final boolean localExecute(Request request) {
-        return request.local();
-    }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequest.java b/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequest.java
index 0b392caa3e588..0b66e3d932603 100644
--- a/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequest.java
@@ -32,70 +32,22 @@
 
 package org.opensearch.action.support.master.info;
 
-import org.opensearch.Version;
-import org.opensearch.action.IndicesRequest;
-import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadRequest;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
-public abstract class ClusterInfoRequest<Request extends ClusterInfoRequest<Request>> extends MasterNodeReadRequest<Request>
-    implements
-        IndicesRequest.Replaceable {
-
-    private String[] indices = Strings.EMPTY_ARRAY;
-
-    private IndicesOptions indicesOptions = IndicesOptions.strictExpandOpen();
+/**
+ * Transport request for cluster information
+ *
+ * @opensearch.internal
+ */
+public abstract class ClusterInfoRequest<Request extends ClusterInfoRequest<Request>> extends
+    org.opensearch.action.support.clustermanager.info.ClusterInfoRequest<Request> {
 
     public ClusterInfoRequest() {}
 
     public ClusterInfoRequest(StreamInput in) throws IOException {
         super(in);
-        indices = in.readStringArray();
-        if (in.getVersion().before(Version.V_2_0_0)) {
-            in.readStringArray();
-        }
-        indicesOptions = IndicesOptions.readIndicesOptions(in);
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        out.writeStringArray(indices);
-        if (out.getVersion().before(Version.V_2_0_0)) {
-            out.writeStringArray(Strings.EMPTY_ARRAY);
-        }
-        indicesOptions.writeIndicesOptions(out);
-    }
-
-    @Override
-    @SuppressWarnings("unchecked")
-    public Request indices(String... indices) {
-        this.indices = indices;
-        return (Request) this;
     }
 
-    @SuppressWarnings("unchecked")
-    public Request indicesOptions(IndicesOptions indicesOptions) {
-        this.indicesOptions = indicesOptions;
-        return (Request) this;
-    }
-
-    @Override
-    public String[] indices() {
-        return indices;
-    }
-
-    @Override
-    public IndicesOptions indicesOptions() {
-        return indicesOptions;
-    }
-
-    @Override
-    public boolean includeDataStreams() {
-        return true;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequestBuilder.java
index d806f96eb9ff2..091413c0df6d7 100644
--- a/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/master/info/ClusterInfoRequestBuilder.java
@@ -32,39 +32,21 @@
 package org.opensearch.action.support.master.info;
 
 import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.master.MasterNodeReadOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.action.ActionResponse;
 
+/**
+ * Transport request builder for cluster information
+ *
+ * @opensearch.internal
+ */
 public abstract class ClusterInfoRequestBuilder<
     Request extends ClusterInfoRequest<Request>,
     Response extends ActionResponse,
-    Builder extends ClusterInfoRequestBuilder<Request, Response, Builder>> extends MasterNodeReadOperationRequestBuilder<
-        Request,
-        Response,
-        Builder> {
+    Builder extends ClusterInfoRequestBuilder<Request, Response, Builder>> extends
+    org.opensearch.action.support.clustermanager.info.ClusterInfoRequestBuilder<Request, Response, Builder> {
 
     protected ClusterInfoRequestBuilder(OpenSearchClient client, ActionType<Response> action, Request request) {
         super(client, action, request);
     }
-
-    @SuppressWarnings("unchecked")
-    public Builder setIndices(String... indices) {
-        request.indices(indices);
-        return (Builder) this;
-    }
-
-    @SuppressWarnings("unchecked")
-    public Builder addIndices(String... indices) {
-        request.indices(ArrayUtils.concat(request.indices(), indices));
-        return (Builder) this;
-    }
-
-    @SuppressWarnings("unchecked")
-    public Builder setIndicesOptions(IndicesOptions indicesOptions) {
-        request.indicesOptions(indicesOptions);
-        return (Builder) this;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/info/TransportClusterInfoAction.java b/server/src/main/java/org/opensearch/action/support/master/info/TransportClusterInfoAction.java
index 9bcfaea056a89..2653e3a658674 100644
--- a/server/src/main/java/org/opensearch/action/support/master/info/TransportClusterInfoAction.java
+++ b/server/src/main/java/org/opensearch/action/support/master/info/TransportClusterInfoAction.java
@@ -31,21 +31,21 @@
 
 package org.opensearch.action.support.master.info;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.TransportMasterNodeReadAction;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Perform cluster information action
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportClusterInfoAction<Request extends ClusterInfoRequest<Request>, Response extends ActionResponse> extends
-    TransportMasterNodeReadAction<Request, Response> {
+    org.opensearch.action.support.clustermanager.info.TransportClusterInfoAction<Request, Response> {
 
     public TransportClusterInfoAction(
         String actionName,
@@ -59,28 +59,4 @@ public TransportClusterInfoAction(
         super(actionName, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
     }
 
-    @Override
-    protected String executor() {
-        // read operation, lightweight...
-        return ThreadPool.Names.SAME;
-    }
-
-    @Override
-    protected ClusterBlockException checkBlock(Request request, ClusterState state) {
-        return state.blocks()
-            .indicesBlockedException(ClusterBlockLevel.METADATA_READ, indexNameExpressionResolver.concreteIndexNames(state, request));
-    }
-
-    @Override
-    protected final void masterOperation(final Request request, final ClusterState state, final ActionListener<Response> listener) {
-        String[] concreteIndices = indexNameExpressionResolver.concreteIndexNames(state, request);
-        doMasterOperation(request, concreteIndices, state, listener);
-    }
-
-    protected abstract void doMasterOperation(
-        Request request,
-        String[] concreteIndices,
-        ClusterState state,
-        ActionListener<Response> listener
-    );
 }
diff --git a/server/src/main/java/org/opensearch/action/support/master/info/package-info.java b/server/src/main/java/org/opensearch/action/support/master/info/package-info.java
new file mode 100644
index 0000000000000..8f21383c1b90c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/master/info/package-info.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Master Node Information transport handlers.
+ *
+ * As of 2.1, because supporting inclusive language, replaced by {@link org.opensearch.action.support.clustermanager.info}
+ */
+@Deprecated
+package org.opensearch.action.support.master.info;
diff --git a/server/src/main/java/org/opensearch/action/support/master/package-info.java b/server/src/main/java/org/opensearch/action/support/master/package-info.java
new file mode 100644
index 0000000000000..9e90d96986fe1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/master/package-info.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Master Node transport handlers.
+ *
+ * As of 2.1, because supporting inclusive language, replaced by {@link org.opensearch.action.support.clustermanager}
+ */
+@Deprecated
+package org.opensearch.action.support.master;
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeRequest.java b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeRequest.java
index e91a659d331d1..eff5d99c90405 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeRequest.java
@@ -33,13 +33,21 @@
 package org.opensearch.action.support.nodes;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
-// TODO: this class can be removed in master once 7.x is bumped to 7.4.0
+/**
+ * Base class for node transport requests
+ *
+ * @opensearch.internal
+ *
+ * @deprecated this class is deprecated and classes will extend TransportRequest directly
+ */
+// TODO: this class can be removed in main once 7.x is bumped to 7.4.0
+@Deprecated
 public abstract class BaseNodeRequest extends TransportRequest {
 
     public BaseNodeRequest() {}
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeResponse.java b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeResponse.java
index 13d9293c21123..8a4e12567b515 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodeResponse.java
@@ -33,14 +33,16 @@
 package org.opensearch.action.support.nodes;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
 /**
  * A base class for node level operations.
+ *
+ * @opensearch.internal
  */
 public abstract class BaseNodeResponse extends TransportResponse {
 
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesRequest.java b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesRequest.java
index b36fc585e99a8..f5fb41dc5bae3 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesRequest.java
@@ -36,12 +36,17 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Base class for requests targeting a list of nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseNodesRequest<Request extends BaseNodesRequest<Request>> extends ActionRequest {
 
     /**
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesResponse.java b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesResponse.java
index 2ba00d77d0660..c51a4f6bb9399 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/BaseNodesResponse.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.support.nodes;
 
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Transport response for nodes requests
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseNodesResponse<TNodeResponse extends BaseNodeResponse> extends ActionResponse {
 
     private ClusterName clusterName;
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/NodesOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/nodes/NodesOperationRequestBuilder.java
index d8017ace7d3e6..ba1e214fe9d19 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/NodesOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/NodesOperationRequestBuilder.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.support.nodes;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Builder for Operation Requests
+ *
+ * @opensearch.internal
+ */
 public abstract class NodesOperationRequestBuilder<
     Request extends BaseNodesRequest<Request>,
     Response extends BaseNodesResponse,
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/TransportNodesAction.java b/server/src/main/java/org/opensearch/action/support/nodes/TransportNodesAction.java
index 030b14678c0e5..1b44ee562a4ed 100644
--- a/server/src/main/java/org/opensearch/action/support/nodes/TransportNodesAction.java
+++ b/server/src/main/java/org/opensearch/action/support/nodes/TransportNodesAction.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.support.nodes;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
@@ -41,8 +40,9 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.NodeShouldNotConnectException;
@@ -62,6 +62,11 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReferenceArray;
 
+/**
+ * Base action class for transport nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportNodesAction<
     NodesRequest extends BaseNodesRequest<NodesRequest>,
     NodesResponse extends BaseNodesResponse,
@@ -211,6 +216,11 @@ protected String getTransportNodeAction(DiscoveryNode node) {
         return transportNodeAction;
     }
 
+    /**
+     * Asynchronous action
+     *
+     * @opensearch.internal
+     */
     class AsyncAction {
 
         private final NodesRequest request;
@@ -306,6 +316,11 @@ private void finishHim() {
         }
     }
 
+    /**
+     * A node transport handler
+     *
+     * @opensearch.internal
+     */
     class NodeTransportHandler implements TransportRequestHandler<NodeRequest> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/action/support/nodes/package-info.java b/server/src/main/java/org/opensearch/action/support/nodes/package-info.java
new file mode 100644
index 0000000000000..f388527e30d8b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/nodes/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node request transport handlers. */
+package org.opensearch.action.support.nodes;
diff --git a/server/src/main/java/org/opensearch/action/support/package-info.java b/server/src/main/java/org/opensearch/action/support/package-info.java
new file mode 100644
index 0000000000000..58dd4c5190d8b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Transport handler Support Classes. */
+package org.opensearch.action.support;
diff --git a/server/src/main/java/org/opensearch/action/support/replication/BasicReplicationRequest.java b/server/src/main/java/org/opensearch/action/support/replication/BasicReplicationRequest.java
index 1022a476bf885..b2a53fec5c281 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/BasicReplicationRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/BasicReplicationRequest.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
@@ -42,6 +42,8 @@
  * Unfortunately ReplicationRequest can't be declared as a type parameter
  * because it has a self referential type parameter of its own. So use this
  * instead.
+ *
+ * @opensearch.internal
  */
 public class BasicReplicationRequest extends ReplicationRequest<BasicReplicationRequest> {
     /**
diff --git a/server/src/main/java/org/opensearch/action/support/replication/FanoutReplicationProxy.java b/server/src/main/java/org/opensearch/action/support/replication/FanoutReplicationProxy.java
new file mode 100644
index 0000000000000..95c4ef1e2b092
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/FanoutReplicationProxy.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.support.replication;
+
+import org.opensearch.action.support.replication.ReplicationOperation.ReplicaResponse;
+import org.opensearch.action.support.replication.ReplicationOperation.Replicas;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.core.action.ActionListener;
+
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+/**
+ * This implementation of {@link ReplicationProxy} fans out the replication request to current shard routing if
+ * it is not the primary and has replication mode as {@link ReplicationMode#FULL_REPLICATION}.
+ *
+ * @opensearch.internal
+ */
+public class FanoutReplicationProxy<ReplicaRequest extends ReplicationRequest<ReplicaRequest>> extends ReplicationProxy<ReplicaRequest> {
+
+    public FanoutReplicationProxy(Replicas<ReplicaRequest> replicasProxy) {
+        super(replicasProxy);
+    }
+
+    @Override
+    protected void performOnReplicaProxy(
+        ReplicationProxyRequest<ReplicaRequest> proxyRequest,
+        ReplicationMode replicationMode,
+        BiConsumer<Consumer<ActionListener<ReplicaResponse>>, ReplicationProxyRequest<ReplicaRequest>> performOnReplicaConsumer
+    ) {
+        assert replicationMode == ReplicationMode.FULL_REPLICATION : "FanoutReplicationProxy allows only full replication mode";
+        performOnReplicaConsumer.accept(getReplicasProxyConsumer(fullReplicationProxy, proxyRequest), proxyRequest);
+    }
+
+    @Override
+    ReplicationMode determineReplicationMode(ShardRouting shardRouting, ShardRouting primaryRouting) {
+        return shardRouting.isSameAllocation(primaryRouting) == false ? ReplicationMode.FULL_REPLICATION : ReplicationMode.NO_REPLICATION;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/replication/PendingReplicationActions.java b/server/src/main/java/org/opensearch/action/support/replication/PendingReplicationActions.java
index 1e554913e527d..c52bc6c2c799d 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/PendingReplicationActions.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/PendingReplicationActions.java
@@ -35,9 +35,10 @@
 import org.opensearch.action.support.RetryableAction;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexShardClosedException;
+import org.opensearch.index.shard.PrimaryShardClosedException;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.ArrayList;
@@ -45,7 +46,13 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
+/**
+ * Pending Replication Actions
+ *
+ * @opensearch.internal
+ */
 public class PendingReplicationActions implements Consumer<ReplicationGroup>, Releasable {
 
     private final Map<String, Set<RetryableAction<?>>> onGoingReplicationActions = ConcurrentCollections.newConcurrentMap();
@@ -116,7 +123,7 @@ synchronized void acceptNewTrackedAllocationIds(Set<String> trackedAllocationIds
             }
         }
 
-        cancelActions(toCancel, "Replica left ReplicationGroup");
+        cancelActions(toCancel, () -> new IndexShardClosedException(shardId, "Replica left ReplicationGroup"));
     }
 
     @Override
@@ -124,15 +131,11 @@ public synchronized void close() {
         ArrayList<Set<RetryableAction<?>>> toCancel = new ArrayList<>(onGoingReplicationActions.values());
         onGoingReplicationActions.clear();
 
-        cancelActions(toCancel, "Primary closed.");
+        cancelActions(toCancel, () -> new PrimaryShardClosedException(shardId));
     }
 
-    private void cancelActions(ArrayList<Set<RetryableAction<?>>> toCancel, String message) {
+    private void cancelActions(ArrayList<Set<RetryableAction<?>>> toCancel, Supplier<IndexShardClosedException> exceptionSupplier) {
         threadPool.executor(ThreadPool.Names.GENERIC)
-            .execute(
-                () -> toCancel.stream()
-                    .flatMap(Collection::stream)
-                    .forEach(action -> action.cancel(new IndexShardClosedException(shardId, message)))
-            );
+            .execute(() -> toCancel.stream().flatMap(Collection::stream).forEach(action -> action.cancel(exceptionSupplier.get())));
     }
 }
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicatedWriteRequest.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicatedWriteRequest.java
index e18765d7a3546..55773c8721c2a 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicatedWriteRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicatedWriteRequest.java
@@ -37,15 +37,17 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Requests that are both {@linkplain ReplicationRequest}s (run on a shard's primary first, then the replica) and {@linkplain WriteRequest}
  * (modify documents on a shard), for example {@link BulkShardRequest}, {@link IndexRequest}, and {@link DeleteRequest}.
+ *
+ * @opensearch.internal
  */
 public abstract class ReplicatedWriteRequest<R extends ReplicatedWriteRequest<R>> extends ReplicationRequest<R> implements WriteRequest<R> {
     private RefreshPolicy refreshPolicy = RefreshPolicy.NONE;
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationMode.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationMode.java
new file mode 100644
index 0000000000000..f9b85cc4bd7aa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationMode.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.support.replication;
+
+/**
+ * The type of replication used for inter-node replication.
+ *
+ * @opensearch.internal
+ */
+public enum ReplicationMode {
+    /**
+     * In this mode, a {@code TransportReplicationAction} is fanned out to underlying concerned shard and is replicated logically.
+     * In short, this mode would replicate the {@link ReplicationRequest} to
+     * the replica shard along with primary term validation.
+     */
+    FULL_REPLICATION,
+    /**
+     * In this mode, a {@code TransportReplicationAction} is fanned out to underlying concerned shard and used for
+     * primary term validation only. The request is not replicated logically.
+     */
+    PRIMARY_TERM_VALIDATION,
+    /**
+     * In this mode, a {@code TransportReplicationAction} does not fan out to the underlying concerned shard.
+     */
+    NO_REPLICATION;
+}
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationModeAwareProxy.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationModeAwareProxy.java
new file mode 100644
index 0000000000000..189bc82348a0c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationModeAwareProxy.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.support.replication;
+
+import org.opensearch.action.support.replication.ReplicationOperation.ReplicaResponse;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.core.action.ActionListener;
+
+import java.util.Objects;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+/**
+ * This implementation of {@link ReplicationProxy} fans out the replication request to current shard routing basis
+ * the shard routing's replication mode and replication override policy.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationModeAwareProxy<ReplicaRequest extends ReplicationRequest<ReplicaRequest>> extends ReplicationProxy<ReplicaRequest> {
+
+    private final ReplicationMode replicationModeOverride;
+
+    /**
+     * This ReplicasProxy is used for performing primary term validation.
+     */
+    private final ReplicationOperation.Replicas<ReplicaRequest> primaryTermValidationProxy;
+
+    public ReplicationModeAwareProxy(
+        ReplicationMode replicationModeOverride,
+        ReplicationOperation.Replicas<ReplicaRequest> replicasProxy,
+        ReplicationOperation.Replicas<ReplicaRequest> primaryTermValidationProxy
+    ) {
+        super(replicasProxy);
+        this.replicationModeOverride = Objects.requireNonNull(replicationModeOverride);
+        this.primaryTermValidationProxy = Objects.requireNonNull(primaryTermValidationProxy);
+    }
+
+    @Override
+    protected void performOnReplicaProxy(
+        ReplicationProxyRequest<ReplicaRequest> proxyRequest,
+        ReplicationMode replicationMode,
+        BiConsumer<Consumer<ActionListener<ReplicaResponse>>, ReplicationProxyRequest<ReplicaRequest>> performOnReplicaConsumer
+    ) {
+        assert replicationMode == ReplicationMode.FULL_REPLICATION || replicationMode == ReplicationMode.PRIMARY_TERM_VALIDATION;
+
+        Consumer<ActionListener<ReplicaResponse>> replicasProxyConsumer;
+        if (replicationMode == ReplicationMode.FULL_REPLICATION) {
+            replicasProxyConsumer = getReplicasProxyConsumer(fullReplicationProxy, proxyRequest);
+        } else {
+            replicasProxyConsumer = getReplicasProxyConsumer(primaryTermValidationProxy, proxyRequest);
+        }
+        performOnReplicaConsumer.accept(replicasProxyConsumer, proxyRequest);
+    }
+
+    @Override
+    ReplicationMode determineReplicationMode(ShardRouting shardRouting, ShardRouting primaryRouting) {
+
+        // If the current routing is the primary, then it does not need to be replicated
+        if (shardRouting.isSameAllocation(primaryRouting)) {
+            return ReplicationMode.NO_REPLICATION;
+        }
+
+        if (primaryRouting.relocating() && shardRouting.isSameAllocation(primaryRouting.getTargetRelocatingShard())) {
+            return ReplicationMode.FULL_REPLICATION;
+        }
+
+        return replicationModeOverride;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationOperation.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationOperation.java
index 68c5416f3603e..60c490a50575a 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicationOperation.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationOperation.java
@@ -34,27 +34,28 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.opensearch.Assertions;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.RetryableAction;
 import org.opensearch.action.support.TransportActions;
+import org.opensearch.action.support.replication.ReplicationProxyRequest.Builder;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.NodeClosedException;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ConnectTransportException;
 
@@ -65,8 +66,14 @@
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
 import java.util.function.LongSupplier;
 
+/**
+ * Operation for a replication request
+ *
+ * @opensearch.internal
+ */
 public class ReplicationOperation<
     Request extends ReplicationRequest<Request>,
     ReplicaRequest extends ReplicationRequest<ReplicaRequest>,
@@ -94,6 +101,7 @@ public class ReplicationOperation<
     private final TimeValue initialRetryBackoffBound;
     private final TimeValue retryTimeout;
     private final long primaryTerm;
+    private final ReplicationProxy<ReplicaRequest> replicationProxy;
 
     // exposed for tests
     private final ActionListener<PrimaryResultT> resultListener;
@@ -112,7 +120,8 @@ public ReplicationOperation(
         String opType,
         long primaryTerm,
         TimeValue initialRetryBackoffBound,
-        TimeValue retryTimeout
+        TimeValue retryTimeout,
+        ReplicationProxy<ReplicaRequest> replicationProxy
     ) {
         this.replicasProxy = replicas;
         this.primary = primary;
@@ -124,6 +133,7 @@ public ReplicationOperation(
         this.primaryTerm = primaryTerm;
         this.initialRetryBackoffBound = initialRetryBackoffBound;
         this.retryTimeout = retryTimeout;
+        this.replicationProxy = replicationProxy;
     }
 
     public void execute() throws Exception {
@@ -221,20 +231,28 @@ private void performOnReplicas(
 
         final ShardRouting primaryRouting = primary.routingEntry();
 
-        for (final ShardRouting shard : replicationGroup.getReplicationTargets()) {
-            if (shard.isSameAllocation(primaryRouting) == false) {
-                performOnReplica(shard, replicaRequest, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, pendingReplicationActions);
-            }
+        for (final ShardRouting shardRouting : replicationGroup.getReplicationTargets()) {
+            ReplicationProxyRequest<ReplicaRequest> proxyRequest = new Builder<ReplicaRequest>(
+                shardRouting,
+                primaryRouting,
+                globalCheckpoint,
+                maxSeqNoOfUpdatesOrDeletes,
+                pendingReplicationActions,
+                replicaRequest,
+                primaryTerm
+            ).build();
+            replicationProxy.performOnReplicaProxy(proxyRequest, this::performOnReplica);
         }
     }
 
     private void performOnReplica(
-        final ShardRouting shard,
-        final ReplicaRequest replicaRequest,
-        final long globalCheckpoint,
-        final long maxSeqNoOfUpdatesOrDeletes,
-        final PendingReplicationActions pendingReplicationActions
+        final Consumer<ActionListener<ReplicaResponse>> replicasProxyConsumer,
+        final ReplicationProxyRequest<ReplicaRequest> replicationProxyRequest
     ) {
+        final ShardRouting shard = replicationProxyRequest.getShardRouting();
+        final ReplicaRequest replicaRequest = replicationProxyRequest.getReplicaRequest();
+        final PendingReplicationActions pendingReplicationActions = replicationProxyRequest.getPendingReplicationActions();
+
         if (logger.isTraceEnabled()) {
             logger.trace("[{}] sending op [{}] to replica {} for request [{}]", shard.shardId(), opType, shard, replicaRequest);
         }
@@ -263,7 +281,8 @@ public void onFailure(Exception replicaException) {
                     ),
                     replicaException
                 );
-                // Only report "critical" exceptions - TODO: Reach out to the master node to get the latest shard state then report.
+                // Only report "critical" exceptions
+                // TODO: Reach out to the cluster-manager node to get the latest shard state then report.
                 if (TransportActions.isShardNotAvailableException(replicaException) == false) {
                     RestStatus restStatus = ExceptionsHelper.status(replicaException);
                     shardReplicaFailures.add(
@@ -303,7 +322,7 @@ public String toString() {
 
             @Override
             public void tryAction(ActionListener<ReplicaResponse> listener) {
-                replicasProxy.performOn(shard, replicaRequest, primaryTerm, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, listener);
+                replicasProxyConsumer.accept(listener);
             }
 
             @Override
@@ -590,6 +609,11 @@ public interface ReplicaResponse {
 
     }
 
+    /**
+     * Thrown if there are any errors retrying on primary
+     *
+     * @opensearch.internal
+     */
     public static class RetryOnPrimaryException extends OpenSearchException {
         RetryOnPrimaryException(ShardId shardId, String msg) {
             this(shardId, msg, null);
@@ -605,6 +629,11 @@ public RetryOnPrimaryException(StreamInput in) throws IOException {
         }
     }
 
+    /**
+     * The result of the primary.
+     *
+     * @opensearch.internal
+     */
     public interface PrimaryResult<RequestT extends ReplicationRequest<RequestT>> {
 
         /**
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxy.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxy.java
new file mode 100644
index 0000000000000..4812984732134
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxy.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.support.replication;
+
+import org.opensearch.action.support.replication.ReplicationOperation.ReplicaResponse;
+import org.opensearch.action.support.replication.ReplicationOperation.Replicas;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.core.action.ActionListener;
+
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+/**
+ * Used for performing any replication operation on replicas. Depending on the implementation, the replication call
+ * can fanout or stops here.
+ *
+ * @opensearch.internal
+ */
+public abstract class ReplicationProxy<ReplicaRequest extends ReplicationRequest<ReplicaRequest>> {
+
+    /**
+     * This is the replicas proxy which is used for full replication.
+     */
+    protected final Replicas<ReplicaRequest> fullReplicationProxy;
+
+    public ReplicationProxy(Replicas<ReplicaRequest> fullReplicationProxy) {
+        this.fullReplicationProxy = fullReplicationProxy;
+    }
+
+    /**
+     * Depending on the actual implementation and the passed {@link ReplicationMode}, the replication
+     * mode is determined using which the replication request is performed on the replica or not.
+     *
+     * @param proxyRequest                     replication proxy request
+     * @param performOnReplicaConsumer performOnReplicasProxy
+     */
+    final void performOnReplicaProxy(
+        ReplicationProxyRequest<ReplicaRequest> proxyRequest,
+        BiConsumer<Consumer<ActionListener<ReplicaResponse>>, ReplicationProxyRequest<ReplicaRequest>> performOnReplicaConsumer
+    ) {
+        ReplicationMode replicationMode = determineReplicationMode(proxyRequest.getShardRouting(), proxyRequest.getPrimaryRouting());
+        // If the replication modes are 1. Logical replication or 2. Primary term validation, we let the call get performed on the
+        // replica shard.
+        if (replicationMode == ReplicationMode.NO_REPLICATION) {
+            return;
+        }
+        performOnReplicaProxy(proxyRequest, replicationMode, performOnReplicaConsumer);
+    }
+
+    /**
+     * The implementor can decide the {@code Consumer<ActionListener<ReplicationOperation.ReplicaResponse>>} basis the
+     * proxyRequest and replicationMode. This will ultimately make the calls to replica.
+     *
+     * @param proxyRequest                     replication proxy request
+     * @param replicationMode                  replication mode
+     * @param performOnReplicaConsumer performOnReplicasProxy
+     */
+    protected abstract void performOnReplicaProxy(
+        ReplicationProxyRequest<ReplicaRequest> proxyRequest,
+        ReplicationMode replicationMode,
+        BiConsumer<Consumer<ActionListener<ReplicaResponse>>, ReplicationProxyRequest<ReplicaRequest>> performOnReplicaConsumer
+    );
+
+    /**
+     * Determines what is the replication mode basis the constructor arguments of the implementation and the current
+     * replication mode aware shard routing.
+     *
+     * @param shardRouting   replication mode aware ShardRouting
+     * @param primaryRouting primary ShardRouting
+     * @return the determined replication mode.
+     */
+    abstract ReplicationMode determineReplicationMode(final ShardRouting shardRouting, final ShardRouting primaryRouting);
+
+    protected Consumer<ActionListener<ReplicaResponse>> getReplicasProxyConsumer(
+        Replicas<ReplicaRequest> proxy,
+        ReplicationProxyRequest<ReplicaRequest> proxyRequest
+    ) {
+        return (listener) -> proxy.performOn(
+            proxyRequest.getShardRouting(),
+            proxyRequest.getReplicaRequest(),
+            proxyRequest.getPrimaryTerm(),
+            proxyRequest.getGlobalCheckpoint(),
+            proxyRequest.getMaxSeqNoOfUpdatesOrDeletes(),
+            listener
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxyRequest.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxyRequest.java
new file mode 100644
index 0000000000000..c65e55867f706
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationProxyRequest.java
@@ -0,0 +1,128 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.support.replication;
+
+import org.opensearch.cluster.routing.ShardRouting;
+
+import java.util.Objects;
+
+/**
+ * This is proxy wrapper over the replication request whose object can be created using the Builder present inside.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationProxyRequest<ReplicaRequest> {
+
+    private final ShardRouting shardRouting;
+
+    private final ShardRouting primaryRouting;
+
+    private final long globalCheckpoint;
+
+    private final long maxSeqNoOfUpdatesOrDeletes;
+
+    private final PendingReplicationActions pendingReplicationActions;
+
+    private final ReplicaRequest replicaRequest;
+
+    private final long primaryTerm;
+
+    private ReplicationProxyRequest(
+        ShardRouting shardRouting,
+        ShardRouting primaryRouting,
+        long globalCheckpoint,
+        long maxSeqNoOfUpdatesOrDeletes,
+        PendingReplicationActions pendingReplicationActions,
+        ReplicaRequest replicaRequest,
+        long primaryTerm
+    ) {
+        this.shardRouting = Objects.requireNonNull(shardRouting);
+        this.primaryRouting = Objects.requireNonNull(primaryRouting);
+        this.globalCheckpoint = globalCheckpoint;
+        this.maxSeqNoOfUpdatesOrDeletes = maxSeqNoOfUpdatesOrDeletes;
+        this.pendingReplicationActions = Objects.requireNonNull(pendingReplicationActions);
+        this.replicaRequest = Objects.requireNonNull(replicaRequest);
+        this.primaryTerm = primaryTerm;
+    }
+
+    public ShardRouting getShardRouting() {
+        return shardRouting;
+    }
+
+    public ShardRouting getPrimaryRouting() {
+        return primaryRouting;
+    }
+
+    public long getGlobalCheckpoint() {
+        return globalCheckpoint;
+    }
+
+    public long getMaxSeqNoOfUpdatesOrDeletes() {
+        return maxSeqNoOfUpdatesOrDeletes;
+    }
+
+    public PendingReplicationActions getPendingReplicationActions() {
+        return pendingReplicationActions;
+    }
+
+    public ReplicaRequest getReplicaRequest() {
+        return replicaRequest;
+    }
+
+    public long getPrimaryTerm() {
+        return primaryTerm;
+    }
+
+    /**
+     * Builder of ReplicationProxyRequest.
+     *
+     * @opensearch.internal
+     */
+    public static class Builder<ReplicaRequest> {
+
+        private final ShardRouting shardRouting;
+        private final ShardRouting primaryRouting;
+        private final long globalCheckpoint;
+        private final long maxSeqNoOfUpdatesOrDeletes;
+        private final PendingReplicationActions pendingReplicationActions;
+        private final ReplicaRequest replicaRequest;
+        private final long primaryTerm;
+
+        public Builder(
+            ShardRouting shardRouting,
+            ShardRouting primaryRouting,
+            long globalCheckpoint,
+            long maxSeqNoOfUpdatesOrDeletes,
+            PendingReplicationActions pendingReplicationActions,
+            ReplicaRequest replicaRequest,
+            long primaryTerm
+        ) {
+            this.shardRouting = shardRouting;
+            this.primaryRouting = primaryRouting;
+            this.globalCheckpoint = globalCheckpoint;
+            this.maxSeqNoOfUpdatesOrDeletes = maxSeqNoOfUpdatesOrDeletes;
+            this.pendingReplicationActions = pendingReplicationActions;
+            this.replicaRequest = replicaRequest;
+            this.primaryTerm = primaryTerm;
+        }
+
+        public ReplicationProxyRequest<ReplicaRequest> build() {
+            return new ReplicationProxyRequest<>(
+                shardRouting,
+                primaryRouting,
+                globalCheckpoint,
+                maxSeqNoOfUpdatesOrDeletes,
+                pendingReplicationActions,
+                replicaRequest,
+                primaryTerm
+            );
+        }
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequest.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequest.java
index e7428e2913f1a..92e50f7a476f3 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequest.java
@@ -40,12 +40,12 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Map;
@@ -56,6 +56,8 @@
 /**
  * Requests that are run on a particular replica, first on the primary and then on the replicas like {@link IndexRequest} or
  * {@link TransportShardRefreshAction}.
+ *
+ * @opensearch.internal
  */
 public abstract class ReplicationRequest<Request extends ReplicationRequest<Request>> extends ActionRequest implements IndicesRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequestBuilder.java
index 1994c70aec17c..920024b366a4c 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationRequestBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
 
+/**
+ * Transport request builder for a replication operation
+ *
+ * @opensearch.internal
+ */
 public abstract class ReplicationRequestBuilder<
     Request extends ReplicationRequest<Request>,
     Response extends ActionResponse,
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationResponse.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationResponse.java
index 6434d36861c6f..400c68ea0e113 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicationResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationResponse.java
@@ -34,28 +34,30 @@
 
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Base class for write action responses.
+ *
+ * @opensearch.internal
  */
 public class ReplicationResponse extends ActionResponse {
 
@@ -83,6 +85,11 @@ public void setShardInfo(ShardInfo shardInfo) {
         this.shardInfo = shardInfo;
     }
 
+    /**
+     * Holds shard information
+     *
+     * @opensearch.internal
+     */
     public static class ShardInfo implements Writeable, ToXContentObject {
 
         private static final String TOTAL = "total";
@@ -225,6 +232,11 @@ public String toString() {
             return "ShardInfo{" + "total=" + total + ", successful=" + successful + ", failures=" + Arrays.toString(failures) + '}';
         }
 
+        /**
+         * Holds failure information
+         *
+         * @opensearch.internal
+         */
         public static class Failure extends ShardOperationFailedException implements ToXContentObject {
 
             private static final String _INDEX = "_index";
diff --git a/server/src/main/java/org/opensearch/action/support/replication/ReplicationTask.java b/server/src/main/java/org/opensearch/action/support/replication/ReplicationTask.java
index b24dcd0648043..c92d2a6e8108e 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/ReplicationTask.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/ReplicationTask.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Map;
@@ -46,6 +47,8 @@
 
 /**
  * Task that tracks replication actions.
+ *
+ * @opensearch.internal
  */
 public class ReplicationTask extends Task {
     private volatile String phase = "starting";
@@ -73,6 +76,11 @@ public Status getStatus() {
         return new Status(phase);
     }
 
+    /**
+     * Status of the replication task
+     *
+     * @opensearch.internal
+     */
     public static class Status implements Task.Status {
         public static final String NAME = "replication";
 
@@ -106,7 +114,7 @@ public void writeTo(StreamOutput out) throws IOException {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
         // Implements equals and hashcode for testing
diff --git a/server/src/main/java/org/opensearch/action/support/replication/TransportBroadcastReplicationAction.java b/server/src/main/java/org/opensearch/action/support/replication/TransportBroadcastReplicationAction.java
index dd1ce9f70a28a..e235adbc162fc 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/TransportBroadcastReplicationAction.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/TransportBroadcastReplicationAction.java
@@ -32,11 +32,8 @@
 
 package org.opensearch.action.support.replication;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
@@ -47,9 +44,11 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -61,6 +60,8 @@
 /**
  * Base class for requests that should be executed on all shards of an index or several indices.
  * This action sends shard requests to all primary shards of the indices and they are then replicated like write requests
+ *
+ * @opensearch.internal
  */
 public abstract class TransportBroadcastReplicationAction<
     Request extends BroadcastRequest<Request>,
@@ -152,11 +153,12 @@ protected List<ShardId> shards(Request request, ClusterState clusterState) {
         for (String index : concreteIndices) {
             IndexMetadata indexMetadata = clusterState.metadata().getIndices().get(index);
             if (indexMetadata != null) {
-                for (IntObjectCursor<IndexShardRoutingTable> shardRouting : clusterState.getRoutingTable()
+                for (IndexShardRoutingTable shardRouting : clusterState.getRoutingTable()
                     .indicesRouting()
                     .get(index)
-                    .getShards()) {
-                    shardIds.add(shardRouting.value.shardId());
+                    .getShards()
+                    .values()) {
+                    shardIds.add(shardRouting.shardId());
                 }
             }
         }
diff --git a/server/src/main/java/org/opensearch/action/support/replication/TransportReplicationAction.java b/server/src/main/java/org/opensearch/action/support/replication/TransportReplicationAction.java
index 0ea08eccae33d..de5a92fdcc4b1 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/TransportReplicationAction.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/TransportReplicationAction.java
@@ -34,18 +34,16 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.ChannelActionListener;
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.action.support.TransportActions;
+import org.opensearch.action.support.replication.ReplicationOperation.Replicas;
 import org.opensearch.client.transport.NoNodeAvailableException;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
@@ -58,9 +56,6 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.ClusterSettings;
@@ -68,20 +63,26 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.TransportChannel;
@@ -103,6 +104,8 @@
  * The action samples cluster state on the receiving node to reroute to node with primary copy and on the
  * primary node to validate request before primary operation followed by sampling state again for resolving
  * nodes with replica copies to perform replication.
+ *
+ * @opensearch.internal
  */
 public abstract class TransportReplicationAction<
     Request extends ReplicationRequest<Request>,
@@ -252,10 +255,46 @@ private void runReroutePhase(Task task, Request request, ActionListener<Response
         }
     }
 
-    protected ReplicationOperation.Replicas<ReplicaRequest> newReplicasProxy() {
+    protected Replicas<ReplicaRequest> newReplicasProxy() {
         return new ReplicasProxy();
     }
 
+    /**
+     * This returns a ReplicaProxy that is used for primary term validation. The default behavior is that the control
+     * must not reach inside the performOn method for ReplicationActions. However, the implementations of the underlying
+     * class can provide primary term validation proxy that can allow performOn method to make calls to replica.
+     *
+     * @return Primary term validation replicas proxy.
+     */
+    protected Replicas<ReplicaRequest> primaryTermValidationReplicasProxy() {
+        return new ReplicasProxy() {
+            @Override
+            public void performOn(
+                ShardRouting replica,
+                ReplicaRequest request,
+                long primaryTerm,
+                long globalCheckpoint,
+                long maxSeqNoOfUpdatesOrDeletes,
+                ActionListener<ReplicationOperation.ReplicaResponse> listener
+            ) {
+                throw new UnsupportedOperationException("Primary term validation is not available for " + actionName);
+            }
+        };
+    }
+
+    /**
+     * This method is used for defining the {@link ReplicationMode} override per {@link TransportReplicationAction}.
+     *
+     * @param indexShard index shard used to determining the policy.
+     * @return the overridden replication mode.
+     */
+    public ReplicationMode getReplicationMode(IndexShard indexShard) {
+        if (indexShard.isRemoteTranslogEnabled()) {
+            return ReplicationMode.NO_REPLICATION;
+        }
+        return ReplicationMode.FULL_REPLICATION;
+    }
+
     protected abstract Response newResponseInstance(StreamInput in) throws IOException;
 
     /**
@@ -384,6 +423,11 @@ protected Releasable checkPrimaryLimits(final Request request, boolean rerouteWa
         return () -> {};
     }
 
+    /**
+     * Asynchronous primary action
+     *
+     * @opensearch.internal
+     */
     class AsyncPrimaryAction extends AbstractRunnable {
         private final ActionListener<Response> onCompletionListener;
         private final ReplicationTask replicationTask;
@@ -516,17 +560,24 @@ public void handleException(TransportException exp) {
                         onCompletionListener.onResponse(response);
                     }, e -> handleException(primaryShardReference, e));
 
+                    final Replicas<ReplicaRequest> replicasProxy = newReplicasProxy();
+                    final IndexShard indexShard = primaryShardReference.indexShard;
+                    final Replicas<ReplicaRequest> termValidationProxy = primaryTermValidationReplicasProxy();
+
                     new ReplicationOperation<>(
                         primaryRequest.getRequest(),
                         primaryShardReference,
                         ActionListener.map(responseListener, result -> result.finalResponseIfSuccessful),
-                        newReplicasProxy(),
+                        replicasProxy,
                         logger,
                         threadPool,
                         actionName,
                         primaryRequest.getPrimaryTerm(),
                         initialRetryBackoffBound,
-                        retryTimeout
+                        retryTimeout,
+                        indexShard.isRemoteTranslogEnabled()
+                            ? new ReplicationModeAwareProxy<>(getReplicationMode(indexShard), replicasProxy, termValidationProxy)
+                            : new FanoutReplicationProxy<>(replicasProxy)
                     ).execute();
                 }
             } catch (Exception e) {
@@ -552,6 +603,11 @@ protected void adaptResponse(Response response, IndexShard indexShard) {
 
     }
 
+    /**
+     * The Primary Result
+     *
+     * @opensearch.internal
+     */
     public static class PrimaryResult<ReplicaRequest extends ReplicationRequest<ReplicaRequest>, Response extends ReplicationResponse>
         implements
             ReplicationOperation.PrimaryResult<ReplicaRequest> {
@@ -601,6 +657,11 @@ public void runPostReplicationActions(ActionListener<Void> listener) {
         }
     }
 
+    /**
+     * The replica result
+     *
+     * @opensearch.internal
+     */
     public static class ReplicaResult {
         final Exception finalFailure;
 
@@ -643,6 +704,11 @@ protected Releasable checkReplicaLimits(final ReplicaRequest request) {
         return () -> {};
     }
 
+    /**
+     * Thrown if there are any errors retrying on the replica
+     *
+     * @opensearch.internal
+     */
     public static class RetryOnReplicaException extends OpenSearchException {
 
         public RetryOnReplicaException(ShardId shardId, String msg) {
@@ -655,6 +721,11 @@ public RetryOnReplicaException(StreamInput in) throws IOException {
         }
     }
 
+    /**
+     * Asynchronous replica action
+     *
+     * @opensearch.internal
+     */
     private final class AsyncReplicaAction extends AbstractRunnable implements ActionListener<Releasable> {
         private final ActionListener<ReplicaResponse> onCompletionListener;
         private final IndexShard replica;
@@ -786,7 +857,7 @@ protected void doRun() throws Exception {
         }
     }
 
-    private IndexShard getIndexShard(final ShardId shardId) {
+    protected IndexShard getIndexShard(final ShardId shardId) {
         IndexService indexService = indicesService.indexServiceSafe(shardId.getIndex());
         return indexService.getShard(shardId.id());
     }
@@ -797,6 +868,8 @@ private IndexShard getIndexShard(final ShardId shardId) {
      * node with primary copy.
      *
      * Resolves index and shard id for the request before routing it to target node
+     *
+     * @opensearch.internal
      */
     final class ReroutePhase extends AbstractRunnable {
         private final ActionListener<Response> listener;
@@ -1131,6 +1204,11 @@ protected void acquireReplicaOperationPermit(
         replica.acquireReplicaOperationPermit(primaryTerm, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, onAcquired, executor, request);
     }
 
+    /**
+     * The primary shard reference
+     *
+     * @opensearch.internal
+     */
     class PrimaryShardReference
         implements
             Releasable,
@@ -1223,11 +1301,16 @@ public PendingReplicationActions getPendingReplicationActions() {
         }
     }
 
+    /**
+     * The replica response
+     *
+     * @opensearch.internal
+     */
     public static class ReplicaResponse extends ActionResponse implements ReplicationOperation.ReplicaResponse {
         private long localCheckpoint;
         private long globalCheckpoint;
 
-        ReplicaResponse(StreamInput in) throws IOException {
+        public ReplicaResponse(StreamInput in) throws IOException {
             super(in);
             localCheckpoint = in.readZLong();
             globalCheckpoint = in.readZLong();
@@ -1279,8 +1362,10 @@ public int hashCode() {
      * interface that performs the actual {@code ReplicaRequest} on the replica
      * shards. It also encapsulates the logic required for failing the replica
      * if deemed necessary as well as marking it as stale when needed.
+     *
+     * @opensearch.internal
      */
-    protected class ReplicasProxy implements ReplicationOperation.Replicas<ReplicaRequest> {
+    protected class ReplicasProxy implements Replicas<ReplicaRequest> {
 
         @Override
         public void performOn(
@@ -1336,10 +1421,16 @@ public void markShardCopyAsStaleIfNeeded(ShardId shardId, String allocationId, l
         }
     }
 
-    /** a wrapper class to encapsulate a request when being sent to a specific allocation id **/
+    /**
+     * a wrapper class to encapsulate a request when being sent to a specific allocation id
+     *
+     * @opensearch.internal
+     */
     public static class ConcreteShardRequest<R extends TransportRequest> extends TransportRequest {
 
-        /** {@link AllocationId#getId()} of the shard this request is sent to **/
+        /**
+         * {@link AllocationId#getId()} of the shard this request is sent to
+         **/
         private final String targetAllocationID;
         private final long primaryTerm;
         private final R request;
@@ -1440,6 +1531,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Internal request for concrete replica
+     *
+     * @opensearch.internal
+     */
     protected static final class ConcreteReplicaRequest<R extends TransportRequest> extends ConcreteShardRequest<R> {
 
         private final long globalCheckpoint;
@@ -1501,7 +1597,7 @@ public String toString() {
      * Sets the current phase on the task if it isn't null. Pulled into its own
      * method because its more convenient that way.
      */
-    static void setPhase(ReplicationTask task, String phase) {
+    protected static void setPhase(ReplicationTask task, String phase) {
         if (task != null) {
             task.setPhase(phase);
         }
diff --git a/server/src/main/java/org/opensearch/action/support/replication/TransportWriteAction.java b/server/src/main/java/org/opensearch/action/support/replication/TransportWriteAction.java
index c9fb959306b9c..62cbfbde9780a 100644
--- a/server/src/main/java/org/opensearch/action/support/replication/TransportWriteAction.java
+++ b/server/src/main/java/org/opensearch/action/support/replication/TransportWriteAction.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.TransportActions;
@@ -46,14 +45,16 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.PrimaryShardClosedException;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.Translog.Location;
 import org.opensearch.indices.IndicesService;
@@ -69,6 +70,8 @@
 /**
  * Base class for transport actions that modify data in some shard like index, delete, and shardBulk.
  * Allows performing async actions (e.g. refresh) after performing write operations on primary and replica shards
+ *
+ * @opensearch.internal
  */
 public abstract class TransportWriteAction<
     Request extends ReplicatedWriteRequest<Request>,
@@ -265,6 +268,8 @@ protected abstract void dispatchedShardOperationOnReplica(
      * Result of taking the action on the primary.
      *
      * NOTE: public for testing
+     *
+     * @opensearch.internal
      */
     public static class WritePrimaryResult<
         ReplicaRequest extends ReplicatedWriteRequest<ReplicaRequest>,
@@ -320,6 +325,8 @@ public void onFailure(Exception ex) {
 
     /**
      * Result of taking the action on the replica.
+     *
+     * @opensearch.internal
      */
     public static class WriteReplicaResult<ReplicaRequest extends ReplicatedWriteRequest<ReplicaRequest>> extends ReplicaResult {
         public final Location location;
@@ -392,6 +399,8 @@ interface RespondingWriteResult {
      * This class encapsulates post write actions like async waits for
      * translog syncs or waiting for a refresh to happen making the write operation
      * visible.
+     *
+     * @opensearch.internal
      */
     static final class AsyncAfterWriteAction {
         private final Location location;
@@ -490,8 +499,10 @@ void run() {
      *
      * This extends {@code TransportReplicationAction.ReplicasProxy} to do the
      * failing and stale-ing.
+     *
+     * @opensearch.internal
      */
-    class WriteActionReplicasProxy extends ReplicasProxy {
+    protected class WriteActionReplicasProxy extends ReplicasProxy {
 
         @Override
         public void failShardIfNeeded(
@@ -504,15 +515,20 @@ public void failShardIfNeeded(
             if (TransportActions.isShardNotAvailableException(exception) == false) {
                 logger.warn(new ParameterizedMessage("[{}] {}", replica.shardId(), message), exception);
             }
-            shardStateAction.remoteShardFailed(
-                replica.shardId(),
-                replica.allocationId().getId(),
-                primaryTerm,
-                true,
-                message,
-                exception,
-                listener
-            );
+            // If a write action fails due to the closure of the primary shard
+            // then the replicas should not be marked as failed since they are
+            // still up-to-date with the (now closed) primary shard
+            if (exception instanceof PrimaryShardClosedException == false) {
+                shardStateAction.remoteShardFailed(
+                    replica.shardId(),
+                    replica.allocationId().getId(),
+                    primaryTerm,
+                    true,
+                    message,
+                    exception,
+                    listener
+                );
+            }
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/action/support/replication/package-info.java b/server/src/main/java/org/opensearch/action/support/replication/package-info.java
new file mode 100644
index 0000000000000..912cd9197b10f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/replication/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Replication transport handlers. */
+package org.opensearch.action.support.replication;
diff --git a/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequest.java b/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequest.java
index 0dd72671fb8c3..9422524133dbf 100644
--- a/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequest.java
@@ -38,16 +38,21 @@
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Transport Request for an Index Shard Operation
+ *
+ * @opensearch.internal
+ */
 // TODO: This request and its associated transport action can be folded into UpdateRequest which is its only concrete production code
-//       implementation
+// implementation
 public abstract class InstanceShardOperationRequest<Request extends InstanceShardOperationRequest<Request>> extends ActionRequest
     implements
         IndicesRequest {
diff --git a/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequestBuilder.java
index 7bbbd7d11e6ab..30ebf1fb419bf 100644
--- a/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/single/instance/InstanceShardOperationRequestBuilder.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.action.support.single.instance;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionResponse;
 
+/**
+ * Request builder for a shard operation
+ *
+ * @opensearch.internal
+ */
 public abstract class InstanceShardOperationRequestBuilder<
     Request extends InstanceShardOperationRequest<Request>,
     Response extends ActionResponse,
diff --git a/server/src/main/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationAction.java b/server/src/main/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationAction.java
index f91b2e8ce2e98..21d4ba726e86f 100644
--- a/server/src/main/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationAction.java
+++ b/server/src/main/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationAction.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.action.support.single.instance;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
@@ -47,12 +45,14 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -69,6 +69,11 @@
 
 import static org.opensearch.cluster.metadata.IndexNameExpressionResolver.EXCLUDED_DATA_STREAMS_KEY;
 
+/**
+ * Base class for a single operation action
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportInstanceSingleOperationAction<
     Request extends InstanceShardOperationRequest<Request>,
     Response extends ActionResponse> extends HandledTransportAction<Request, Response> {
@@ -135,6 +140,11 @@ protected TransportRequestOptions transportOptions() {
      */
     protected abstract ShardIterator shards(ClusterState clusterState, Request request);
 
+    /**
+     * Asynchronous single action
+     *
+     * @opensearch.internal
+     */
     class AsyncSingleAction {
 
         private final ActionListener<Response> listener;
@@ -286,6 +296,11 @@ public void onTimeout(TimeValue timeout) {
         }
     }
 
+    /**
+     * Transport handler per shard
+     *
+     * @opensearch.internal
+     */
     private class ShardTransportHandler implements TransportRequestHandler<Request> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/action/support/single/instance/package-info.java b/server/src/main/java/org/opensearch/action/support/single/instance/package-info.java
new file mode 100644
index 0000000000000..1acd5c1503ed0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/single/instance/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Single Instance transport handlers. */
+package org.opensearch.action.support.single.instance;
diff --git a/server/src/main/java/org/opensearch/action/support/single/package-info.java b/server/src/main/java/org/opensearch/action/support/single/package-info.java
new file mode 100644
index 0000000000000..918a755936fe3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/single/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Single instance transport handlers. */
+package org.opensearch.action.support.single;
diff --git a/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardOperationRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardOperationRequestBuilder.java
index d981bfaf60f2c..2c602cbc2d164 100644
--- a/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardOperationRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardOperationRequestBuilder.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.action.support.single.shard;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.OpenSearchClient;
+import org.opensearch.core.action.ActionResponse;
 
+/**
+ * Request builder for a single shard operation request
+ *
+ * @opensearch.internal
+ */
 public abstract class SingleShardOperationRequestBuilder<
     Request extends SingleShardRequest<Request>,
     Response extends ActionResponse,
diff --git a/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardRequest.java b/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardRequest.java
index faae069b4b7fa..c474096ff94e4 100644
--- a/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/single/shard/SingleShardRequest.java
@@ -38,12 +38,17 @@
 import org.opensearch.action.ValidateActions;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Single shard request.
+ *
+ * @opensearch.internal
+ */
 public abstract class SingleShardRequest<Request extends SingleShardRequest<Request>> extends ActionRequest implements IndicesRequest {
 
     public static final IndicesOptions INDICES_OPTIONS = IndicesOptions.strictSingleIndexNoExpandForbidClosed();
diff --git a/server/src/main/java/org/opensearch/action/support/single/shard/TransportSingleShardAction.java b/server/src/main/java/org/opensearch/action/support/single/shard/TransportSingleShardAction.java
index 2a03abac733cd..df91559a2f8cb 100644
--- a/server/src/main/java/org/opensearch/action/support/single/shard/TransportSingleShardAction.java
+++ b/server/src/main/java/org/opensearch/action/support/single/shard/TransportSingleShardAction.java
@@ -33,8 +33,6 @@
 package org.opensearch.action.support.single.shard;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.support.ActionFilters;
@@ -47,14 +45,17 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.FailAwareWeightedRouting;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.logging.LoggerMessageFormat;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.logging.LoggerMessageFormat;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportChannel;
@@ -71,6 +72,8 @@
  * A base class for operations that need to perform a read operation on a single shard copy. If the operation fails,
  * the read operation can be performed on other shard copies. Concrete implementations can provide their own list
  * of candidate shards to try the read operation on.
+ *
+ * @opensearch.internal
  */
 public abstract class TransportSingleShardAction<Request extends SingleShardRequest<Request>, Response extends ActionResponse> extends
     TransportAction<Request, Response> {
@@ -151,6 +154,11 @@ protected void resolveRequest(ClusterState state, InternalRequest request) {
     @Nullable
     protected abstract ShardsIterator shards(ClusterState state, InternalRequest request);
 
+    /**
+     * Asynchronous single action
+     *
+     * @opensearch.internal
+     */
     class AsyncSingleAction {
 
         private final ActionListener<Response> listener;
@@ -237,7 +245,9 @@ private void perform(@Nullable final Exception currentFailure) {
                 lastFailure = currentFailure;
                 this.lastFailure = currentFailure;
             }
-            final ShardRouting shardRouting = shardIt.nextOrNull();
+            ShardRouting shardRouting = FailAwareWeightedRouting.getInstance()
+                .findNext(shardIt, clusterService.state(), currentFailure, () -> {});
+
             if (shardRouting == null) {
                 Exception failure = lastFailure;
                 if (failure == null || isShardNotAvailableException(failure)) {
@@ -266,6 +276,7 @@ private void perform(@Nullable final Exception currentFailure) {
                     );
                 }
                 final Writeable.Reader<Response> reader = getResponseReader();
+                ShardRouting finalShardRouting = shardRouting;
                 transportService.sendRequest(
                     node,
                     transportShardAction,
@@ -289,7 +300,7 @@ public void handleResponse(final Response response) {
 
                         @Override
                         public void handleException(TransportException exp) {
-                            onFailure(shardRouting, exp);
+                            onFailure(finalShardRouting, exp);
                         }
                     }
                 );
@@ -297,6 +308,11 @@ public void handleException(TransportException exp) {
         }
     }
 
+    /**
+     * Internal transport handler
+     *
+     * @opensearch.internal
+     */
     private class TransportHandler implements TransportRequestHandler<Request> {
 
         @Override
@@ -306,6 +322,11 @@ public void messageReceived(Request request, final TransportChannel channel, Tas
         }
     }
 
+    /**
+     * Shard level transport handler
+     *
+     * @opensearch.internal
+     */
     private class ShardTransportHandler implements TransportRequestHandler<Request> {
 
         @Override
@@ -319,6 +340,8 @@ public void messageReceived(final Request request, final TransportChannel channe
 
     /**
      * Internal request class that gets built on each node. Holds the original request plus additional info.
+     *
+     * @opensearch.internal
      */
     protected class InternalRequest {
         final Request request;
diff --git a/server/src/main/java/org/opensearch/action/support/single/shard/package-info.java b/server/src/main/java/org/opensearch/action/support/single/shard/package-info.java
new file mode 100644
index 0000000000000..0d93688ece5f1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/single/shard/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Single Shard transport handlers. */
+package org.opensearch.action.support.single.shard;
diff --git a/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksRequest.java b/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksRequest.java
index bbe7b918b26a5..a10f74f7c2aa8 100644
--- a/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksRequest.java
+++ b/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksRequest.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 
@@ -49,6 +49,8 @@
 
 /**
  * A base class for task requests
+ *
+ * @opensearch.internal
  */
 public class BaseTasksRequest<Request extends BaseTasksRequest<Request>> extends ActionRequest {
 
diff --git a/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksResponse.java b/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksResponse.java
index 3ba32cf2a3b12..d7b73361ee249 100644
--- a/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksResponse.java
+++ b/server/src/main/java/org/opensearch/action/support/tasks/BaseTasksResponse.java
@@ -33,14 +33,14 @@
 package org.opensearch.action.support.tasks;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,6 +54,8 @@
 
 /**
  * Base class for responses of task-related operations
+ *
+ * @opensearch.internal
  */
 public class BaseTasksResponse extends ActionResponse {
     protected static final String TASK_FAILURES = "task_failures";
diff --git a/server/src/main/java/org/opensearch/action/support/tasks/TasksRequestBuilder.java b/server/src/main/java/org/opensearch/action/support/tasks/TasksRequestBuilder.java
index 0dd0f585ae9e6..a8bf264828122 100644
--- a/server/src/main/java/org/opensearch/action/support/tasks/TasksRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/support/tasks/TasksRequestBuilder.java
@@ -31,14 +31,16 @@
 
 package org.opensearch.action.support.tasks;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 
 /**
  * Builder for task-based requests
+ *
+ * @opensearch.internal
  */
 public class TasksRequestBuilder<
     Request extends BaseTasksRequest<Request>,
diff --git a/server/src/main/java/org/opensearch/action/support/tasks/TransportTasksAction.java b/server/src/main/java/org/opensearch/action/support/tasks/TransportTasksAction.java
index 7bd5a8503b123..f33d7161660a3 100644
--- a/server/src/main/java/org/opensearch/action/support/tasks/TransportTasksAction.java
+++ b/server/src/main/java/org/opensearch/action/support/tasks/TransportTasksAction.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.NoSuchNodeException;
 import org.opensearch.action.TaskOperationFailure;
@@ -44,12 +43,13 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.NodeShouldNotConnectException;
@@ -58,13 +58,13 @@
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReferenceArray;
 import java.util.function.Consumer;
@@ -73,6 +73,8 @@
 
 /**
  * The base class for transport actions that are interacting with currently running tasks.
+ *
+ * @opensearch.internal
  */
 public abstract class TransportTasksAction<
     OperationTask extends Task,
@@ -235,6 +237,11 @@ protected TasksResponse newResponse(TasksRequest request, AtomicReferenceArray r
      */
     protected abstract void taskOperation(TasksRequest request, OperationTask task, ActionListener<TaskResponse> listener);
 
+    /**
+     * Asynchronous single action
+     *
+     * @opensearch.internal
+     */
     private class AsyncAction {
 
         private final TasksRequest request;
@@ -252,7 +259,7 @@ private AsyncAction(Task task, TasksRequest request, ActionListener<TasksRespons
             ClusterState clusterState = clusterService.state();
             String[] nodesIds = resolveNodes(request, clusterState);
             this.nodesIds = filterNodeIds(clusterState.nodes(), nodesIds);
-            ImmutableOpenMap<String, DiscoveryNode> nodes = clusterState.nodes().getNodes();
+            final Map<String, DiscoveryNode> nodes = clusterState.nodes().getNodes();
             this.nodes = new DiscoveryNode[nodesIds.length];
             for (int i = 0; i < this.nodesIds.length; i++) {
                 this.nodes[i] = nodes.get(this.nodesIds[i]);
@@ -351,6 +358,11 @@ private void finishHim() {
         }
     }
 
+    /**
+     * Node level transport handler
+     *
+     * @opensearch.internal
+     */
     class NodeTransportHandler implements TransportRequestHandler<NodeTaskRequest> {
 
         @Override
@@ -366,6 +378,11 @@ public void messageReceived(final NodeTaskRequest request, final TransportChanne
         }
     }
 
+    /**
+     * Node level task request
+     *
+     * @opensearch.internal
+     */
     private class NodeTaskRequest extends TransportRequest {
         private TasksRequest tasksRequest;
 
@@ -387,6 +404,11 @@ protected NodeTaskRequest(TasksRequest tasksRequest) {
 
     }
 
+    /**
+     * Node level task response
+     *
+     * @opensearch.internal
+     */
     private class NodeTasksResponse extends TransportResponse {
         protected String nodeId;
         protected List<TaskOperationFailure> exceptions;
diff --git a/server/src/main/java/org/opensearch/action/support/tasks/package-info.java b/server/src/main/java/org/opensearch/action/support/tasks/package-info.java
new file mode 100644
index 0000000000000..30924e1433c7b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/support/tasks/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Task Request transport handlers. */
+package org.opensearch.action.support.tasks;
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsAction.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsAction.java
index a14ae0ce94cc7..27d93f2a8e916 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * A single multi term action.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsAction extends ActionType<MultiTermVectorsResponse> {
 
     public static final MultiTermVectorsAction INSTANCE = new MultiTermVectorsAction();
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsItemResponse.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsItemResponse.java
index 037f4b95e3c73..80ca1629417ad 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsItemResponse.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsItemResponse.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.action.termvectors;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
 /**
- * A single multi get response.
+ * A single multi term response.
+ *
+ * @opensearch.internal
  */
 public class MultiTermVectorsItemResponse implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequest.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequest.java
index aada19b081a1c..c055564c3fcbe 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequest.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequest.java
@@ -39,9 +39,9 @@
 import org.opensearch.action.RealtimeRequest;
 import org.opensearch.action.ValidateActions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -51,6 +51,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * A single multi get request.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsRequest extends ActionRequest
     implements
         Iterable<TermVectorsRequest>,
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequestBuilder.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequestBuilder.java
index 51711c01beb44..04dfd39112d6e 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsRequestBuilder.java
@@ -35,6 +35,11 @@
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * A single multi get request builder.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsRequestBuilder extends ActionRequestBuilder<MultiTermVectorsRequest, MultiTermVectorsResponse> {
 
     public MultiTermVectorsRequestBuilder(OpenSearchClient client, MultiTermVectorsAction action) {
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsResponse.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsResponse.java
index 599c2fa883dc7..5d40e64df1e3e 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsResponse.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsResponse.java
@@ -34,21 +34,28 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 
+/**
+ * A multi get response.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsResponse extends ActionResponse implements Iterable<MultiTermVectorsItemResponse>, ToXContentObject {
 
     /**
      * Represents a failure.
+     *
+     * @opensearch.internal
      */
     public static class Failure implements Writeable {
         private final String index;
@@ -146,10 +153,14 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String DOCS = "docs";
         static final String _INDEX = "_index";
-        static final String _TYPE = "_type";
         static final String _ID = "_id";
     }
 
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardRequest.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardRequest.java
index 85491b37b4914..a31e3085cbc17 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardRequest.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardRequest.java
@@ -32,28 +32,32 @@
 
 package org.opensearch.action.termvectors;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * A multi get shard request.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsShardRequest extends SingleShardRequest<MultiTermVectorsShardRequest> {
 
     private int shardId;
     private String preference;
 
-    IntArrayList locations;
+    List<Integer> locations;
     List<TermVectorsRequest> requests;
 
     MultiTermVectorsShardRequest(StreamInput in) throws IOException {
         super(in);
         int size = in.readVInt();
-        locations = new IntArrayList(size);
+        locations = new ArrayList<>(size);
         requests = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
             locations.add(in.readVInt());
@@ -66,7 +70,7 @@ public class MultiTermVectorsShardRequest extends SingleShardRequest<MultiTermVe
     MultiTermVectorsShardRequest(String index, int shardId) {
         super(index);
         this.shardId = shardId;
-        locations = new IntArrayList();
+        locations = new ArrayList<>();
         requests = new ArrayList<>();
     }
 
@@ -81,7 +85,8 @@ public int shardId() {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public MultiTermVectorsShardRequest preference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardResponse.java b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardResponse.java
index b01582230ed85..674b285a7b3ce 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardResponse.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/MultiTermVectorsShardResponse.java
@@ -32,23 +32,27 @@
 
 package org.opensearch.action.termvectors;
 
-import com.carrotsearch.hppc.IntArrayList;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * A multi get shard response.
+ *
+ * @opensearch.internal
+ */
 public class MultiTermVectorsShardResponse extends ActionResponse {
 
-    final IntArrayList locations;
+    final List<Integer> locations;
     final List<TermVectorsResponse> responses;
     final List<MultiTermVectorsResponse.Failure> failures;
 
     MultiTermVectorsShardResponse() {
-        locations = new IntArrayList();
+        locations = new ArrayList<>();
         responses = new ArrayList<>();
         failures = new ArrayList<>();
     }
@@ -56,7 +60,7 @@ public class MultiTermVectorsShardResponse extends ActionResponse {
     MultiTermVectorsShardResponse(StreamInput in) throws IOException {
         super(in);
         int size = in.readVInt();
-        locations = new IntArrayList(size);
+        locations = new ArrayList<>(size);
         responses = new ArrayList<>(size);
         failures = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsAction.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsAction.java
index acdeb3d18c880..e810621b1a064 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsAction.java
@@ -34,6 +34,12 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Transport action for returning the term vector (doc frequency, positions, offsets) for a
+ * document.
+ *
+ * @opensearch.internal
+ */
 public class TermVectorsAction extends ActionType<TermVectorsResponse> {
 
     public static final TermVectorsAction INSTANCE = new TermVectorsAction();
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFields.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFields.java
index 0033e9299b76d..ed3dca815090d 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFields.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFields.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.action.termvectors;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
-import com.carrotsearch.hppc.cursors.ObjectLongCursor;
 import org.apache.lucene.index.BaseTermsEnum;
 import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.ImpactsEnum;
@@ -46,12 +44,15 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.RamUsageEstimator;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.Map;
 
 import static org.apache.lucene.util.ArrayUtil.grow;
 
@@ -130,11 +131,12 @@
  * <li>BytesRef: payload_freqency (if payloads)</li>
  * </ul></li>
  * </ul>
+ *
+ * @opensearch.internal
  */
-
 public final class TermVectorsFields extends Fields {
 
-    private final ObjectLongHashMap<String> fieldMap;
+    private final Map<String, Long> fieldMap;
     private final BytesReference termVectors;
     final boolean hasTermStatistic;
     final boolean hasFieldStatistic;
@@ -156,10 +158,11 @@ public TermVectorsFields(BytesReference headerRef, BytesReference termVectors) t
             hasFieldStatistic = header.readBoolean();
             hasScores = header.readBoolean();
             final int numFields = header.readVInt();
-            fieldMap = new ObjectLongHashMap<>(numFields);
+            final Map<String, Long> fieldMap = new HashMap<>(numFields);
             for (int i = 0; i < numFields; i++) {
                 fieldMap.put((header.readString()), header.readVLong());
             }
+            this.fieldMap = Collections.unmodifiableMap(fieldMap);
         }
         // reference to the term vector data
         this.termVectors = termVectors;
@@ -167,8 +170,8 @@ public TermVectorsFields(BytesReference headerRef, BytesReference termVectors) t
 
     @Override
     public Iterator<String> iterator() {
-        final Iterator<ObjectLongCursor<String>> iterator = fieldMap.iterator();
-        return new Iterator<String>() {
+        final Iterator<Map.Entry<String, Long>> iterator = fieldMap.entrySet().iterator();
+        return new Iterator<>() {
             @Override
             public boolean hasNext() {
                 return iterator.hasNext();
@@ -176,7 +179,7 @@ public boolean hasNext() {
 
             @Override
             public String next() {
-                return iterator.next().key;
+                return iterator.next().getKey();
             }
 
             @Override
@@ -190,12 +193,11 @@ public void remove() {
     public Terms terms(String field) throws IOException {
         // first, find where in the termVectors bytes the actual term vector for
         // this field is stored
-        final int keySlot = fieldMap.indexOf(field);
-        if (keySlot < 0) {
+        final Long keySlot = fieldMap.get(field);
+        if (keySlot == null) {
             return null; // we don't have it.
         }
-        long readOffset = fieldMap.indexGet(keySlot);
-        return new TermVector(termVectors, readOffset);
+        return new TermVector(termVectors, keySlot);
     }
 
     @Override
@@ -203,6 +205,11 @@ public int size() {
         return fieldMap.size();
     }
 
+    /**
+     * Internal term vector
+     *
+     * @opensearch.internal
+     */
     private final class TermVector extends Terms {
 
         private final StreamInput perFieldTermVectorInput;
@@ -419,6 +426,11 @@ public boolean hasPayloads() {
         }
     }
 
+    /**
+     * Internal postings enumerator for term vectors
+     *
+     * @opensearch.internal
+     */
     private final class TermVectorPostingsEnum extends PostingsEnum {
         private boolean hasPositions;
         private boolean hasOffsets;
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFilter.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFilter.java
index 2d2650e2b9389..0e0202777794b 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFilter.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsFilter.java
@@ -45,6 +45,12 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Filter the term vector (doc frequency, positions, offsets) for a
+ * document.
+ *
+ * @opensearch.internal
+ */
 public class TermVectorsFilter {
     public static final int DEFAULT_MAX_QUERY_TERMS = 25;
     public static final int DEFAULT_MIN_TERM_FREQ = 0;
@@ -170,6 +176,11 @@ public void setMaxWordLength(int maxWordLength) {
         this.maxWordLength = maxWordLength;
     }
 
+    /**
+     * Internal score term
+     *
+     * @opensearch.internal
+     */
     public static final class ScoreTerm {
         public String field;
         public String word;
@@ -289,6 +300,11 @@ private float computeScore(long docFreq, int freq, long numDocs) {
         return freq * similarity.idf(docFreq, numDocs);
     }
 
+    /**
+     * Internal queue of score terms
+     *
+     * @opensearch.internal
+     */
     private static class ScoreTermsQueue extends org.apache.lucene.util.PriorityQueue<ScoreTerm> {
         private final int limit;
 
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
index 214d5f0d6d4fa..d49d087316afa 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
@@ -41,17 +41,18 @@
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
 
@@ -73,6 +74,8 @@
  * <p>
  * Note, the {@link #index()}, and {@link #id(String)} are
  * required.
+ *
+ * @opensearch.internal
  */
 public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> implements RealtimeRequest {
     private static final ParseField INDEX = new ParseField("_index");
@@ -92,7 +95,7 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
 
     private BytesReference doc;
 
-    private XContentType xContentType;
+    private MediaType mediaType;
 
     private String routing;
 
@@ -113,6 +116,11 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
 
     private FilterSettings filterSettings;
 
+    /**
+     * Internal filter settings
+     *
+     * @opensearch.internal
+     */
     public static final class FilterSettings {
         public Integer maxNumTerms;
         public Integer minTermFreq;
@@ -179,7 +187,11 @@ public TermVectorsRequest() {}
 
         if (in.readBoolean()) {
             doc = in.readBytesReference();
-            xContentType = in.readEnum(XContentType.class);
+            if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                mediaType = in.readMediaType();
+            } else {
+                mediaType = in.readEnum(XContentType.class);
+            }
         }
         routing = in.readOptionalString();
 
@@ -232,7 +244,7 @@ public TermVectorsRequest(TermVectorsRequest other) {
         this.id = other.id();
         if (other.doc != null) {
             this.doc = new BytesArray(other.doc().toBytesRef(), true);
-            this.xContentType = other.xContentType;
+            this.mediaType = other.mediaType;
         }
         this.flagsEnum = other.getFlags().clone();
         this.preference = other.preference();
@@ -282,8 +294,8 @@ public BytesReference doc() {
         return doc;
     }
 
-    public XContentType xContentType() {
-        return xContentType;
+    public MediaType xContentType() {
+        return mediaType;
     }
 
     /**
@@ -295,23 +307,23 @@ public TermVectorsRequest doc(XContentBuilder documentBuilder) {
 
     /**
      * Sets an artificial document from which term vectors are requested for.
-     * @deprecated use {@link #doc(BytesReference, boolean, XContentType)} to avoid content auto detection
+     * @deprecated use {@link #doc(BytesReference, boolean, MediaType)} to avoid content auto detection
      */
     @Deprecated
     public TermVectorsRequest doc(BytesReference doc, boolean generateRandomId) {
-        return this.doc(doc, generateRandomId, XContentHelper.xContentType(doc));
+        return this.doc(doc, generateRandomId, MediaTypeRegistry.xContentType(doc));
     }
 
     /**
      * Sets an artificial document from which term vectors are requested for.
      */
-    public TermVectorsRequest doc(BytesReference doc, boolean generateRandomId, XContentType xContentType) {
+    public TermVectorsRequest doc(BytesReference doc, boolean generateRandomId, MediaType mediaType) {
         // assign a random id to this artificial document, for routing
         if (generateRandomId) {
             this.id(String.valueOf(randomInt.getAndAdd(1)));
         }
         this.doc = doc;
-        this.xContentType = xContentType;
+        this.mediaType = mediaType;
         return this;
     }
 
@@ -333,8 +345,8 @@ public String preference() {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across
-     * shards. Can be set to {@code _local} to prefer local shards or a custom value,
-     * which guarantees that the same order will be used across different
+     * shards. Can be set to {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order will be used across different
      * requests.
      */
     public TermVectorsRequest preference(String preference) {
@@ -531,7 +543,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeBoolean(doc != null);
         if (doc != null) {
             out.writeBytesReference(doc);
-            out.writeEnum(xContentType);
+            if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                mediaType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) mediaType);
+            }
         }
         out.writeOptionalString(routing);
         if (out.getVersion().before(LegacyESVersion.V_7_0_0)) {
@@ -561,6 +577,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeLong(version);
     }
 
+    /**
+     * The flags.
+     *
+     * @opensearch.internal
+     */
     public enum Flag {
         // Do not change the order of these flags we use
         // the ordinal for encoding! Only append to the end!
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequestBuilder.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequestBuilder.java
index 7294db072ad38..02cfff1a6682b 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequestBuilder.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 
 import java.util.Map;
@@ -45,6 +45,8 @@
  * <p>
  * Note, the {@code index}, {@code type} and {@code id} are
  * required.
+ *
+ * @opensearch.internal
  */
 public class TermVectorsRequestBuilder extends ActionRequestBuilder<TermVectorsRequest, TermVectorsResponse> {
 
@@ -94,7 +96,8 @@ public TermVectorsRequestBuilder setRouting(String routing) {
 
     /**
      * Sets the preference to execute the search. Defaults to randomize across shards. Can be set to
-     * {@code _local} to prefer local shards or a custom value, which guarantees that the same order
+     * {@code _local} to prefer local shards, {@code _primary} to execute only on primary shards,
+     * or a custom value, which guarantees that the same order
      * will be used across different requests.
      */
     public TermVectorsRequestBuilder setPreference(String preference) {
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsResponse.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsResponse.java
index 870609d526909..3c338ce7338bb 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsResponse.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsResponse.java
@@ -41,15 +41,15 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.CharsRefBuilder;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -58,8 +58,19 @@
 import java.util.Iterator;
 import java.util.Set;
 
+/**
+ * Response returning the term vector (doc frequency, positions, offsets) for a
+ * document.
+ *
+ * @opensearch.internal
+ */
 public class TermVectorsResponse extends ActionResponse implements ToXContentObject {
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     private static class FieldStrings {
         // term statistics strings
         public static final String TTF = "ttf";
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsWriter.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsWriter.java
index 2c1e543774da6..b60376d6f7e8d 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsWriter.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsWriter.java
@@ -40,8 +40,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.action.termvectors.TermVectorsRequest.Flag;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -49,6 +49,12 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Writer for the term vector (doc frequency, positions, offsets) for a
+ * document.
+ *
+ * @opensearch.internal
+ */
 // package only - this is an internal class!
 final class TermVectorsWriter {
     final List<String> fields = new ArrayList<>();
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TransportMultiTermVectorsAction.java b/server/src/main/java/org/opensearch/action/termvectors/TransportMultiTermVectorsAction.java
index 127b31f329d09..0364f36106cb0 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TransportMultiTermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TransportMultiTermVectorsAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.termvectors;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.HandledTransportAction;
@@ -42,8 +41,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Performs the multi term get operation.
+ *
+ * @opensearch.internal
+ */
 public class TransportMultiTermVectorsAction extends HandledTransportAction<MultiTermVectorsRequest, MultiTermVectorsResponse> {
 
     private final ClusterService clusterService;
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TransportShardMultiTermsVectorAction.java b/server/src/main/java/org/opensearch/action/termvectors/TransportShardMultiTermsVectorAction.java
index 511b68965ebdf..a298e267cca37 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TransportShardMultiTermsVectorAction.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TransportShardMultiTermsVectorAction.java
@@ -41,15 +41,20 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.termvectors.TermVectorsService;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
+/**
+ * Performs the multi term shard level get operation.
+ *
+ * @opensearch.internal
+ */
 public class TransportShardMultiTermsVectorAction extends TransportSingleShardAction<
     MultiTermVectorsShardRequest,
     MultiTermVectorsShardResponse> {
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TransportTermVectorsAction.java b/server/src/main/java/org/opensearch/action/termvectors/TransportTermVectorsAction.java
index 3cfd9cf7da7c5..b7e8a29bd4027 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TransportTermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TransportTermVectorsAction.java
@@ -32,20 +32,21 @@
 
 package org.opensearch.action.termvectors;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.single.shard.TransportSingleShardAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.routing.GroupShardsIterator;
+import org.opensearch.cluster.routing.Preference;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.termvectors.TermVectorsService;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
@@ -55,6 +56,8 @@
 
 /**
  * Performs the get operation.
+ *
+ * @opensearch.internal
  */
 public class TransportTermVectorsAction extends TransportSingleShardAction<TermVectorsRequest, TermVectorsResponse> {
 
@@ -85,15 +88,24 @@ public TransportTermVectorsAction(
 
     @Override
     protected ShardIterator shards(ClusterState state, InternalRequest request) {
+
+        String preference = request.request().preference;
+        // For a real time request on a seg rep index, use primary shard as the preferred query shard.
+        if (request.request().realtime()
+            && preference == null
+            && state.getMetadata().isSegmentReplicationEnabled(request.concreteIndex())) {
+            preference = Preference.PRIMARY.type();
+        }
+
         if (request.request().doc() != null && request.request().routing() == null) {
             // artificial document without routing specified, ignore its "id" and use either random shard or according to preference
             GroupShardsIterator<ShardIterator> groupShardsIter = clusterService.operationRouting()
-                .searchShards(state, new String[] { request.concreteIndex() }, null, request.request().preference());
+                .searchShards(state, new String[] { request.concreteIndex() }, null, preference);
             return groupShardsIter.iterator().next();
         }
 
         return clusterService.operationRouting()
-            .getShards(state, request.concreteIndex(), request.request().id(), request.request().routing(), request.request().preference());
+            .getShards(state, request.concreteIndex(), request.request().id(), request.request().routing(), preference);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/update/TransportUpdateAction.java b/server/src/main/java/org/opensearch/action/update/TransportUpdateAction.java
index 387c0d24ed4df..819112eb497f6 100644
--- a/server/src/main/java/org/opensearch/action/update/TransportUpdateAction.java
+++ b/server/src/main/java/org/opensearch/action/update/TransportUpdateAction.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.update;
 
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.ResourceAlreadyExistsException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.RoutingMissingException;
@@ -55,18 +55,21 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NotSerializableExceptionWrapper;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NotSerializableExceptionWrapper;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.VersionConflictEngineException;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.IndexingStats.Stats.DocStatusStats;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -81,6 +84,11 @@
 import static org.opensearch.action.bulk.TransportSingleItemBulkWriteAction.toSingleItemBulkRequest;
 import static org.opensearch.action.bulk.TransportSingleItemBulkWriteAction.wrapBulkResponse;
 
+/**
+ * Transport action for updating an index
+ *
+ * @opensearch.internal
+ */
 public class TransportUpdateAction extends TransportInstanceSingleOperationAction<UpdateRequest, UpdateResponse> {
 
     private final AutoCreateIndex autoCreateIndex;
@@ -149,17 +157,20 @@ public static void resolveAndValidateRouting(Metadata metadata, String concreteI
     @Override
     protected void doExecute(Task task, final UpdateRequest request, final ActionListener<UpdateResponse> listener) {
         if (request.isRequireAlias() && (clusterService.state().getMetadata().hasAlias(request.index()) == false)) {
-            throw new IndexNotFoundException(
+            IndexNotFoundException e = new IndexNotFoundException(
                 "[" + DocWriteRequest.REQUIRE_ALIAS + "] request flag is [true] and [" + request.index() + "] is not an alias",
                 request.index()
             );
+
+            incDocStatusStats(e);
+            throw e;
         }
-        // if we don't have a master, we don't have metadata, that's fine, let it find a master using create index API
+        // if we don't have a master, we don't have metadata, that's fine, let it find a cluster-manager using create index API
         if (autoCreateIndex.shouldAutoCreate(request.index(), clusterService.state())) {
             client.admin()
                 .indices()
                 .create(
-                    new CreateIndexRequest().index(request.index()).cause("auto(update api)").masterNodeTimeout(request.timeout()),
+                    new CreateIndexRequest().index(request.index()).cause("auto(update api)").clusterManagerNodeTimeout(request.timeout()),
                     new ActionListener<CreateIndexResponse>() {
                         @Override
                         public void onResponse(CreateIndexResponse result) {
@@ -188,7 +199,10 @@ public void onFailure(Exception e) {
     }
 
     private void innerExecute(final Task task, final UpdateRequest request, final ActionListener<UpdateResponse> listener) {
-        super.doExecute(task, request, listener);
+        super.doExecute(task, request, ActionListener.wrap(listener::onResponse, e -> {
+            incDocStatusStats(e);
+            listener.onFailure(e);
+        }));
     }
 
     @Override
@@ -233,7 +247,7 @@ protected void shardOperation(final UpdateRequest request, final ActionListener<
                         response.getResult()
                     );
                     if (request.fetchSource() != null && request.fetchSource().fetchSource()) {
-                        Tuple<XContentType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(
+                        Tuple<? extends MediaType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(
                             upsertSourceBytes,
                             true,
                             upsertRequest.getContentType()
@@ -325,7 +339,13 @@ protected void shardOperation(final UpdateRequest request, final ActionListener<
                         shard.noopUpdate();
                     }
                 }
+
+                DocStatusStats stats = new DocStatusStats();
+                stats.inc(RestStatus.OK);
+
+                indicesService.addDocStatusStats(stats);
                 listener.onResponse(update);
+
                 break;
             default:
                 throw new IllegalStateException("Illegal result " + result.getResponseResult());
@@ -356,4 +376,10 @@ private void handleUpdateFailureWithRetry(
         }
         listener.onFailure(cause instanceof Exception ? (Exception) cause : new NotSerializableExceptionWrapper(cause));
     }
+
+    private void incDocStatusStats(final Exception e) {
+        DocStatusStats stats = new DocStatusStats();
+        stats.inc(ExceptionsHelper.status(e));
+        indicesService.addDocStatusStats(stats);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/action/update/UpdateAction.java b/server/src/main/java/org/opensearch/action/update/UpdateAction.java
index c82cf96506de4..af520409f498c 100644
--- a/server/src/main/java/org/opensearch/action/update/UpdateAction.java
+++ b/server/src/main/java/org/opensearch/action/update/UpdateAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action for updating an index
+ *
+ * @opensearch.internal
+ */
 public class UpdateAction extends ActionType<UpdateResponse> {
 
     public static final UpdateAction INSTANCE = new UpdateAction();
diff --git a/server/src/main/java/org/opensearch/action/update/UpdateHelper.java b/server/src/main/java/org/opensearch/action/update/UpdateHelper.java
index 0da41a3028edf..19c32f9336df8 100644
--- a/server/src/main/java/org/opensearch/action/update/UpdateHelper.java
+++ b/server/src/main/java/org/opensearch/action/update/UpdateHelper.java
@@ -40,20 +40,22 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.client.Requests;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.DocumentMissingException;
 import org.opensearch.index.engine.DocumentSourceMissingException;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.RoutingFieldMapper;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.UpdateScript;
@@ -67,6 +69,8 @@
 
 /**
  * Helper for translating an update request to an index, delete request or update response.
+ *
+ * @opensearch.internal
  */
 public class UpdateHelper {
 
@@ -162,7 +166,7 @@ Result prepareUpsert(ShardId shardId, UpdateRequest request, final GetResult get
                         DocWriteResponse.Result.NOOP
                     );
                     update.setGetResult(getResult);
-                    return new Result(update, DocWriteResponse.Result.NOOP, upsertResult.v2(), XContentType.JSON);
+                    return new Result(update, DocWriteResponse.Result.NOOP, upsertResult.v2(), MediaTypeRegistry.JSON);
                 default:
                     // It's fine to throw an exception here, the leniency is handled/logged by `executeScriptedUpsert`
                     throw new IllegalArgumentException("unknown upsert operation, got: " + upsertResult.v1());
@@ -350,7 +354,7 @@ public static GetResult extractGetResult(
         long primaryTerm,
         long version,
         final Map<String, Object> source,
-        XContentType sourceContentType,
+        MediaType sourceContentType,
         @Nullable final BytesReference sourceAsBytes
     ) {
         if (request.fetchSource() == null || request.fetchSource().fetchSource() == false) {
@@ -388,18 +392,23 @@ public static GetResult extractGetResult(
         );
     }
 
+    /**
+     * Internal result
+     *
+     * @opensearch.internal
+     */
     public static class Result {
 
         private final Writeable action;
         private final DocWriteResponse.Result result;
         private final Map<String, Object> updatedSourceAsMap;
-        private final XContentType updateSourceContentType;
+        private final MediaType updateSourceContentType;
 
         public Result(
             Writeable action,
             DocWriteResponse.Result result,
             Map<String, Object> updatedSourceAsMap,
-            XContentType updateSourceContentType
+            MediaType updateSourceContentType
         ) {
             this.action = action;
             this.result = result;
@@ -420,7 +429,7 @@ public Map<String, Object> updatedSourceAsMap() {
             return updatedSourceAsMap;
         }
 
-        public XContentType updateSourceContentType() {
+        public MediaType updateSourceContentType() {
             return updateSourceContentType;
         }
     }
@@ -466,6 +475,8 @@ public String toString() {
 
     /**
      * Field names used to populate the script context
+     *
+     * @opensearch.internal
      */
     public static class ContextFields {
         public static final String CTX = "ctx";
@@ -473,7 +484,6 @@ public static class ContextFields {
         public static final String SOURCE = "_source";
         public static final String NOW = "_now";
         public static final String INDEX = "_index";
-        public static final String TYPE = "_type";
         public static final String ID = "_id";
         public static final String VERSION = "_version";
         public static final String ROUTING = "_routing";
diff --git a/server/src/main/java/org/opensearch/action/update/UpdateRequest.java b/server/src/main/java/org/opensearch/action/update/UpdateRequest.java
index 36be9f0160c9a..ca38c0c4273c6 100644
--- a/server/src/main/java/org/opensearch/action/update/UpdateRequest.java
+++ b/server/src/main/java/org/opensearch/action/update/UpdateRequest.java
@@ -43,23 +43,23 @@
 import org.opensearch.action.support.replication.ReplicationRequest;
 import org.opensearch.action.support.single.instance.InstanceShardOperationRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -72,6 +72,11 @@
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 
+/**
+ * Transport request for updating an index
+ *
+ * @opensearch.internal
+ */
 public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     implements
         DocWriteRequest<UpdateRequest>,
@@ -102,12 +107,12 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
         );
         PARSER.declareBoolean(UpdateRequest::scriptedUpsert, SCRIPTED_UPSERT_FIELD);
         PARSER.declareObject((request, builder) -> request.safeUpsertRequest().source(builder), (parser, context) -> {
-            XContentBuilder builder = XContentFactory.contentBuilder(parser.contentType());
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(parser.contentType());
             builder.copyCurrentStructure(parser);
             return builder;
         }, UPSERT_FIELD);
         PARSER.declareObject((request, builder) -> request.safeDoc().source(builder), (parser, context) -> {
-            XContentBuilder docBuilder = XContentFactory.contentBuilder(parser.contentType());
+            XContentBuilder docBuilder = MediaTypeRegistry.contentBuilder(parser.contentType());
             docBuilder.copyCurrentStructure(parser);
             return docBuilder;
         }, DOC_FIELD);
@@ -249,6 +254,9 @@ public ActionRequestValidationException validate() {
         if (doc == null && docAsUpsert) {
             validationException = addValidationError("doc must be specified if doc_as_upsert is enabled", validationException);
         }
+
+        validationException = DocWriteRequest.validateDocIdLength(id, validationException);
+
         return validationException;
     }
 
@@ -677,32 +685,32 @@ public UpdateRequest doc(Map<String, Object> source) {
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequest doc(Map<String, Object> source, XContentType contentType) {
-        safeDoc().source(source, contentType);
+    public UpdateRequest doc(Map<String, Object> source, MediaType mediaType) {
+        safeDoc().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequest doc(String source, XContentType xContentType) {
-        safeDoc().source(source, xContentType);
+    public UpdateRequest doc(String source, MediaType mediaType) {
+        safeDoc().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequest doc(byte[] source, XContentType xContentType) {
-        safeDoc().source(source, xContentType);
+    public UpdateRequest doc(byte[] source, MediaType mediaType) {
+        safeDoc().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequest doc(byte[] source, int offset, int length, XContentType xContentType) {
-        safeDoc().source(source, offset, length, xContentType);
+    public UpdateRequest doc(byte[] source, int offset, int length, MediaType mediaType) {
+        safeDoc().source(source, offset, length, mediaType);
         return this;
     }
 
@@ -719,8 +727,8 @@ public UpdateRequest doc(Object... source) {
      * Sets the doc to use for updates when a script is not specified, the doc provided
      * is a field and value pairs.
      */
-    public UpdateRequest doc(XContentType xContentType, Object... source) {
-        safeDoc().source(xContentType, source);
+    public UpdateRequest doc(MediaType mediaType, Object... source) {
+        safeDoc().source(mediaType, source);
         return this;
     }
 
@@ -763,32 +771,32 @@ public UpdateRequest upsert(Map<String, Object> source) {
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequest upsert(Map<String, Object> source, XContentType contentType) {
-        safeUpsertRequest().source(source, contentType);
+    public UpdateRequest upsert(Map<String, Object> source, MediaType mediaType) {
+        safeUpsertRequest().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequest upsert(String source, XContentType xContentType) {
-        safeUpsertRequest().source(source, xContentType);
+    public UpdateRequest upsert(String source, MediaType mediaType) {
+        safeUpsertRequest().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequest upsert(byte[] source, XContentType xContentType) {
-        safeUpsertRequest().source(source, xContentType);
+    public UpdateRequest upsert(byte[] source, MediaType mediaType) {
+        safeUpsertRequest().source(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequest upsert(byte[] source, int offset, int length, XContentType xContentType) {
-        safeUpsertRequest().source(source, offset, length, xContentType);
+    public UpdateRequest upsert(byte[] source, int offset, int length, MediaType mediaType) {
+        safeUpsertRequest().source(source, offset, length, mediaType);
         return this;
     }
 
@@ -805,8 +813,8 @@ public UpdateRequest upsert(Object... source) {
      * Sets the doc source of the update request to be used when the document does not exists. The doc
      * includes field and value pairs.
      */
-    public UpdateRequest upsert(XContentType xContentType, Object... source) {
-        safeUpsertRequest().source(xContentType, source);
+    public UpdateRequest upsert(MediaType mediaType, Object... source) {
+        safeUpsertRequest().source(mediaType, source);
         return this;
     }
 
@@ -950,13 +958,13 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field("doc_as_upsert", docAsUpsert);
         }
         if (doc != null) {
-            XContentType xContentType = doc.getContentType();
+            MediaType mediaType = doc.getContentType();
             try (
                 XContentParser parser = XContentHelper.createParser(
                     NamedXContentRegistry.EMPTY,
                     LoggingDeprecationHandler.INSTANCE,
                     doc.source(),
-                    xContentType
+                    mediaType
                 )
             ) {
                 builder.field("doc");
@@ -973,13 +981,13 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field("script", script);
         }
         if (upsertRequest != null) {
-            XContentType xContentType = upsertRequest.getContentType();
+            MediaType mediaType = upsertRequest.getContentType();
             try (
                 XContentParser parser = XContentHelper.createParser(
                     NamedXContentRegistry.EMPTY,
                     LoggingDeprecationHandler.INSTANCE,
                     upsertRequest.source(),
-                    xContentType
+                    mediaType
                 )
             ) {
                 builder.field("upsert");
diff --git a/server/src/main/java/org/opensearch/action/update/UpdateRequestBuilder.java b/server/src/main/java/org/opensearch/action/update/UpdateRequestBuilder.java
index 73e470bf8ba69..c97d0b4f5d13d 100644
--- a/server/src/main/java/org/opensearch/action/update/UpdateRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/action/update/UpdateRequestBuilder.java
@@ -39,13 +39,18 @@
 import org.opensearch.action.support.single.instance.InstanceShardOperationRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.script.Script;
 
 import java.util.Map;
 
+/**
+ * Transport request builder for updating an index
+ *
+ * @opensearch.internal
+ */
 public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<UpdateRequest, UpdateResponse, UpdateRequestBuilder>
     implements
         WriteRequestBuilder<UpdateRequestBuilder> {
@@ -225,7 +230,7 @@ public UpdateRequestBuilder setDoc(Map<String, Object> source) {
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequestBuilder setDoc(Map<String, Object> source, XContentType contentType) {
+    public UpdateRequestBuilder setDoc(Map<String, Object> source, MediaType contentType) {
         request.doc(source, contentType);
         return this;
     }
@@ -233,24 +238,24 @@ public UpdateRequestBuilder setDoc(Map<String, Object> source, XContentType cont
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequestBuilder setDoc(String source, XContentType xContentType) {
-        request.doc(source, xContentType);
+    public UpdateRequestBuilder setDoc(String source, MediaType mediaType) {
+        request.doc(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequestBuilder setDoc(byte[] source, XContentType xContentType) {
-        request.doc(source, xContentType);
+    public UpdateRequestBuilder setDoc(byte[] source, MediaType mediaType) {
+        request.doc(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequestBuilder setDoc(byte[] source, int offset, int length, XContentType xContentType) {
-        request.doc(source, offset, length, xContentType);
+    public UpdateRequestBuilder setDoc(byte[] source, int offset, int length, MediaType mediaType) {
+        request.doc(source, offset, length, mediaType);
         return this;
     }
 
@@ -267,8 +272,8 @@ public UpdateRequestBuilder setDoc(Object... source) {
      * Sets the doc to use for updates when a script is not specified, the doc provided
      * is a field and value pairs.
      */
-    public UpdateRequestBuilder setDoc(XContentType xContentType, Object... source) {
-        request.doc(xContentType, source);
+    public UpdateRequestBuilder setDoc(MediaType mediaType, Object... source) {
+        request.doc(mediaType, source);
         return this;
     }
 
@@ -300,32 +305,32 @@ public UpdateRequestBuilder setUpsert(Map<String, Object> source) {
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequestBuilder setUpsert(Map<String, Object> source, XContentType contentType) {
-        request.upsert(source, contentType);
+    public UpdateRequestBuilder setUpsert(Map<String, Object> source, MediaType mediaType) {
+        request.upsert(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequestBuilder setUpsert(String source, XContentType xContentType) {
-        request.upsert(source, xContentType);
+    public UpdateRequestBuilder setUpsert(String source, MediaType mediaType) {
+        request.upsert(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequestBuilder setUpsert(byte[] source, XContentType xContentType) {
-        request.upsert(source, xContentType);
+    public UpdateRequestBuilder setUpsert(byte[] source, MediaType mediaType) {
+        request.upsert(source, mediaType);
         return this;
     }
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
-    public UpdateRequestBuilder setUpsert(byte[] source, int offset, int length, XContentType xContentType) {
-        request.upsert(source, offset, length, xContentType);
+    public UpdateRequestBuilder setUpsert(byte[] source, int offset, int length, MediaType mediaType) {
+        request.upsert(source, offset, length, mediaType);
         return this;
     }
 
@@ -342,8 +347,8 @@ public UpdateRequestBuilder setUpsert(Object... source) {
      * Sets the doc source of the update request to be used when the document does not exists. The doc
      * includes field and value pairs.
      */
-    public UpdateRequestBuilder setUpsert(XContentType xContentType, Object... source) {
-        request.upsert(xContentType, source);
+    public UpdateRequestBuilder setUpsert(MediaType mediaType, Object... source) {
+        request.upsert(mediaType, source);
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/action/update/UpdateResponse.java b/server/src/main/java/org/opensearch/action/update/UpdateResponse.java
index 2c6efaf3c5f6b..d9f6ceacb0f3b 100644
--- a/server/src/main/java/org/opensearch/action/update/UpdateResponse.java
+++ b/server/src/main/java/org/opensearch/action/update/UpdateResponse.java
@@ -33,18 +33,23 @@
 package org.opensearch.action.update;
 
 import org.opensearch.action.DocWriteResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Transport response for updating an index
+ *
+ * @opensearch.internal
+ */
 public class UpdateResponse extends DocWriteResponse {
 
     private static final String GET = "get";
@@ -167,6 +172,8 @@ public static void parseXContentFields(XContentParser parser, Builder context) t
      * Builder class for {@link UpdateResponse}. This builder is usually used during xcontent parsing to
      * temporarily store the parsed values, then the {@link DocWriteResponse.Builder#build()} method is called to
      * instantiate the {@link UpdateResponse}.
+     *
+     * @opensearch.internal
      */
     public static class Builder extends DocWriteResponse.Builder {
 
diff --git a/server/src/main/java/org/opensearch/action/update/package-info.java b/server/src/main/java/org/opensearch/action/update/package-info.java
new file mode 100644
index 0000000000000..a8c8720c9ac10
--- /dev/null
+++ b/server/src/main/java/org/opensearch/action/update/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Update Action transport handlers. */
+package org.opensearch.action.update;
diff --git a/server/src/main/java/org/opensearch/bootstrap/Bootstrap.java b/server/src/main/java/org/opensearch/bootstrap/Bootstrap.java
index 30a883454ba8c..827674c29b9e4 100644
--- a/server/src/main/java/org/opensearch/bootstrap/Bootstrap.java
+++ b/server/src/main/java/org/opensearch/bootstrap/Bootstrap.java
@@ -48,16 +48,15 @@
 import org.opensearch.common.PidFile;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.inject.CreationException;
-import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.logging.LogConfigurator;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.network.IfConfig;
 import org.opensearch.common.settings.KeyStoreWrapper;
 import org.opensearch.common.settings.SecureSettings;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.transport.BoundTransportAddress;
 import org.opensearch.env.Environment;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.os.OsProbe;
@@ -78,12 +77,13 @@
 import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
 import java.util.List;
-import java.util.Locale;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
 /**
  * Internal startup code.
+ *
+ * @opensearch.internal
  */
 final class Bootstrap {
 
@@ -374,14 +374,6 @@ static void init(final boolean foreground, final Path pidFile, final boolean qui
         } catch (IOException e) {
             throw new BootstrapException(e);
         }
-        if (JavaVersion.current().compareTo(JavaVersion.parse("11")) < 0) {
-            final String message = String.format(
-                Locale.ROOT,
-                "future versions of OpenSearch will require Java 11; " + "your Java version from [%s] does not meet this requirement",
-                System.getProperty("java.home")
-            );
-            DeprecationLogger.getLogger(Bootstrap.class).deprecate("java_version_11_required", message);
-        }
         if (environment.pidFile() != null) {
             try {
                 PidFile.create(environment.pidFile(), true);
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapCheck.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapCheck.java
index 230b1bd05e579..a695486bd084c 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapCheck.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapCheck.java
@@ -32,16 +32,22 @@
 
 package org.opensearch.bootstrap;
 
+import org.opensearch.common.annotation.PublicApi;
+
 import java.util.Objects;
 
 /**
  * Encapsulates a bootstrap check.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface BootstrapCheck {
 
     /**
      * Encapsulate the result of a bootstrap check.
      */
+    @PublicApi(since = "1.0.0")
     final class BootstrapCheckResult {
 
         private final String message;
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapChecks.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapChecks.java
index 79019a73c69e3..f9661e71d60e6 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapChecks.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapChecks.java
@@ -36,16 +36,20 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.util.Constants;
+import org.opensearch.bootstrap.jvm.DenyJvmVersionsParser;
 import org.opensearch.cluster.coordination.ClusterBootstrapService;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.DiscoveryModule;
+import org.opensearch.env.Environment;
 import org.opensearch.index.IndexModule;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.process.ProcessProbe;
+import org.opensearch.node.NodeRoleSettings;
 import org.opensearch.node.NodeValidationException;
 
 import java.io.BufferedReader;
@@ -59,8 +63,6 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.function.Predicate;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -73,6 +75,8 @@
  * We enforce bootstrap checks once a node has the transport protocol bound to a non-loopback interface or if the system property {@code
  * opensearch.enforce.bootstrap.checks} is set to {@true}. In this case we assume the node is running in production and
  * all bootstrap checks must pass.
+ *
+ * @opensearch.internal
  */
 final class BootstrapChecks {
 
@@ -224,12 +228,33 @@ static List<BootstrapCheck> checks() {
         checks.add(new OnErrorCheck());
         checks.add(new OnOutOfMemoryErrorCheck());
         checks.add(new EarlyAccessCheck());
-        checks.add(new G1GCCheck());
+        checks.add(new JavaVersionCheck());
         checks.add(new AllPermissionCheck());
         checks.add(new DiscoveryConfiguredCheck());
+        checks.add(new MultipleDataPathCheck());
         return Collections.unmodifiableList(checks);
     }
 
+    static class JavaVersionCheck implements BootstrapCheck {
+        @Override
+        public BootstrapCheckResult check(BootstrapContext context) {
+            return DenyJvmVersionsParser.getDeniedJvmVersions()
+                .stream()
+                .filter(p -> p.test(getVersion()))
+                .findAny()
+                .map(
+                    p -> BootstrapCheckResult.failure(
+                        String.format(Locale.ROOT, "The current JVM version %s is not recommended for use: %s", getVersion(), p.getReason())
+                    )
+                )
+                .orElseGet(() -> BootstrapCheckResult.success());
+        }
+
+        Runtime.Version getVersion() {
+            return Runtime.version();
+        }
+    }
+
     static class HeapSizeCheck implements BootstrapCheck {
 
         @Override
@@ -683,60 +708,6 @@ String javaVersion() {
 
     }
 
-    /**
-     * Bootstrap check for versions of HotSpot that are known to have issues that can lead to index corruption when G1GC is enabled.
-     */
-    static class G1GCCheck implements BootstrapCheck {
-
-        @Override
-        public BootstrapCheckResult check(BootstrapContext context) {
-            if ("Oracle Corporation".equals(jvmVendor()) && isJava8() && isG1GCEnabled()) {
-                final String jvmVersion = jvmVersion();
-                // HotSpot versions on Java 8 match this regular expression; note that this changes with Java 9 after JEP-223
-                final Pattern pattern = Pattern.compile("(\\d+)\\.(\\d+)-b\\d+");
-                final Matcher matcher = pattern.matcher(jvmVersion);
-                final boolean matches = matcher.matches();
-                assert matches : jvmVersion;
-                final int major = Integer.parseInt(matcher.group(1));
-                final int update = Integer.parseInt(matcher.group(2));
-                // HotSpot versions for Java 8 have major version 25, the bad versions are all versions prior to update 40
-                if (major == 25 && update < 40) {
-                    final String message = String.format(
-                        Locale.ROOT,
-                        "JVM version [%s] can cause data corruption when used with G1GC; upgrade to at least Java 8u40",
-                        jvmVersion
-                    );
-                    return BootstrapCheckResult.failure(message);
-                }
-            }
-            return BootstrapCheckResult.success();
-        }
-
-        // visible for testing
-        String jvmVendor() {
-            return Constants.JVM_VENDOR;
-        }
-
-        // visible for testing
-        boolean isG1GCEnabled() {
-            assert "Oracle Corporation".equals(jvmVendor());
-            return JvmInfo.jvmInfo().useG1GC().equals("true");
-        }
-
-        // visible for testing
-        String jvmVersion() {
-            assert "Oracle Corporation".equals(jvmVendor());
-            return Constants.JVM_VERSION;
-        }
-
-        // visible for testing
-        boolean isJava8() {
-            assert "Oracle Corporation".equals(jvmVendor());
-            return JavaVersion.current().equals(JavaVersion.parse("1.8"));
-        }
-
-    }
-
     static class AllPermissionCheck implements BootstrapCheck {
 
         @Override
@@ -784,4 +755,25 @@ public BootstrapCheckResult check(BootstrapContext context) {
             );
         }
     }
+
+    /**
+     * Bootstrap check that if a search node contains multiple data paths
+     */
+    static class MultipleDataPathCheck implements BootstrapCheck {
+
+        @Override
+        public BootstrapCheckResult check(BootstrapContext context) {
+            if (NodeRoleSettings.NODE_ROLES_SETTING.get(context.settings()).contains(DiscoveryNodeRole.SEARCH_ROLE)
+                && Environment.PATH_DATA_SETTING.get(context.settings()).size() > 1) {
+                return BootstrapCheckResult.failure("Multiple data paths are not allowed for search nodes");
+            }
+            return BootstrapCheckResult.success();
+        }
+
+        @Override
+        public final boolean alwaysEnforce() {
+            return true;
+        }
+
+    }
 }
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapContext.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapContext.java
index b07a544e8521e..a7ffd701d07f0 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapContext.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapContext.java
@@ -32,12 +32,16 @@
 package org.opensearch.bootstrap;
 
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 
 /**
  * Context that is passed to every bootstrap check to make decisions on.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class BootstrapContext {
     /**
      * The node's environment
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapException.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapException.java
index 8daa29aa3578b..77b66553cb46d 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapException.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapException.java
@@ -41,6 +41,8 @@
  * these checked exceptions so that
  * {@link Bootstrap#init(boolean, Path, boolean, org.opensearch.env.Environment)}
  * does not have to declare all of these checked exceptions.
+ *
+ * @opensearch.internal
  */
 class BootstrapException extends Exception {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapInfo.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapInfo.java
index d45d8ddab9c2c..0aa965ce46096 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapInfo.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapInfo.java
@@ -39,6 +39,8 @@
 
 /**
  * Exposes system startup information
+ *
+ * @opensearch.internal
  */
 @SuppressForbidden(reason = "exposes read-only view of system properties")
 public final class BootstrapInfo {
diff --git a/server/src/main/java/org/opensearch/bootstrap/BootstrapSettings.java b/server/src/main/java/org/opensearch/bootstrap/BootstrapSettings.java
index 208030b5d6d12..911bc92c433f1 100644
--- a/server/src/main/java/org/opensearch/bootstrap/BootstrapSettings.java
+++ b/server/src/main/java/org/opensearch/bootstrap/BootstrapSettings.java
@@ -35,6 +35,11 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 
+/**
+ * Settings used for bootstrapping OpenSearch
+ *
+ * @opensearch.internal
+ */
 public final class BootstrapSettings {
 
     private BootstrapSettings() {}
diff --git a/server/src/main/java/org/opensearch/bootstrap/ConsoleCtrlHandler.java b/server/src/main/java/org/opensearch/bootstrap/ConsoleCtrlHandler.java
index cbc1b6e761923..ae9b6ea7ce761 100644
--- a/server/src/main/java/org/opensearch/bootstrap/ConsoleCtrlHandler.java
+++ b/server/src/main/java/org/opensearch/bootstrap/ConsoleCtrlHandler.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.bootstrap;
 
+/**
+ * Handler for ctrl events on the console
+ *
+ * @opensearch.internal
+ */
 public interface ConsoleCtrlHandler {
 
     int CTRL_CLOSE_EVENT = 2;
diff --git a/server/src/main/java/org/opensearch/bootstrap/FilePermissionUtils.java b/server/src/main/java/org/opensearch/bootstrap/FilePermissionUtils.java
index b37aef5f9738d..18ff013b1e8cb 100644
--- a/server/src/main/java/org/opensearch/bootstrap/FilePermissionUtils.java
+++ b/server/src/main/java/org/opensearch/bootstrap/FilePermissionUtils.java
@@ -40,6 +40,11 @@
 import java.nio.file.Path;
 import java.security.Permissions;
 
+/**
+ * Utility for File Permissions during bootstrap
+ *
+ * @opensearch.internal
+ */
 public class FilePermissionUtils {
 
     /** no instantiation */
diff --git a/server/src/main/java/org/opensearch/bootstrap/JNACLibrary.java b/server/src/main/java/org/opensearch/bootstrap/JNACLibrary.java
index 7d3ce7728a9dc..aca2cb9656025 100644
--- a/server/src/main/java/org/opensearch/bootstrap/JNACLibrary.java
+++ b/server/src/main/java/org/opensearch/bootstrap/JNACLibrary.java
@@ -45,6 +45,8 @@
 
 /**
  * java mapping to some libc functions
+ *
+ * @opensearch.internal
  */
 final class JNACLibrary {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/JNAKernel32Library.java b/server/src/main/java/org/opensearch/bootstrap/JNAKernel32Library.java
index a0cd656f5fc01..8e556df4b2f9b 100644
--- a/server/src/main/java/org/opensearch/bootstrap/JNAKernel32Library.java
+++ b/server/src/main/java/org/opensearch/bootstrap/JNAKernel32Library.java
@@ -51,6 +51,8 @@
 
 /**
  * Library for Windows/Kernel32
+ *
+ * @opensearch.internal
  */
 final class JNAKernel32Library {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/JNANatives.java b/server/src/main/java/org/opensearch/bootstrap/JNANatives.java
index 1e3c6c3af0386..033596033b0fd 100644
--- a/server/src/main/java/org/opensearch/bootstrap/JNANatives.java
+++ b/server/src/main/java/org/opensearch/bootstrap/JNANatives.java
@@ -48,6 +48,8 @@
 /**
  * This class performs the actual work with JNA and library bindings to call native methods. It should only be used after
  * we are sure that the JNA classes are available to the JVM
+ *
+ * @opensearch.internal
  */
 class JNANatives {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/Natives.java b/server/src/main/java/org/opensearch/bootstrap/Natives.java
index 65025e41958ce..aa5e29fbb2591 100644
--- a/server/src/main/java/org/opensearch/bootstrap/Natives.java
+++ b/server/src/main/java/org/opensearch/bootstrap/Natives.java
@@ -40,6 +40,8 @@
 /**
  * The Natives class is a wrapper class that checks if the classes necessary for calling native methods are available on
  * startup. If they are not available, this class will avoid calling code that loads these classes.
+ *
+ * @opensearch.internal
  */
 final class Natives {
     /** no instantiation */
diff --git a/server/src/main/java/org/opensearch/bootstrap/OpenSearch.java b/server/src/main/java/org/opensearch/bootstrap/OpenSearch.java
index 4395ae98c9ba6..8df1d6c6df3da 100644
--- a/server/src/main/java/org/opensearch/bootstrap/OpenSearch.java
+++ b/server/src/main/java/org/opensearch/bootstrap/OpenSearch.java
@@ -55,6 +55,8 @@
 
 /**
  * This class starts opensearch.
+ *
+ * @opensearch.internal
  */
 class OpenSearch extends EnvironmentAwareCommand {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/OpenSearchPolicy.java b/server/src/main/java/org/opensearch/bootstrap/OpenSearchPolicy.java
index d31f11f153ae8..14435db64274c 100644
--- a/server/src/main/java/org/opensearch/bootstrap/OpenSearchPolicy.java
+++ b/server/src/main/java/org/opensearch/bootstrap/OpenSearchPolicy.java
@@ -48,7 +48,11 @@
 import java.util.Map;
 import java.util.function.Predicate;
 
-/** custom policy for union of static and dynamic permissions */
+/**
+ * custom policy for union of static and dynamic permissions
+ *
+ * @opensearch.internal
+ **/
 final class OpenSearchPolicy extends Policy {
 
     /** template policy file, the one used in tests */
diff --git a/server/src/main/java/org/opensearch/bootstrap/OpenSearchUncaughtExceptionHandler.java b/server/src/main/java/org/opensearch/bootstrap/OpenSearchUncaughtExceptionHandler.java
index 4834f4cb211fe..2b28260097ce1 100644
--- a/server/src/main/java/org/opensearch/bootstrap/OpenSearchUncaughtExceptionHandler.java
+++ b/server/src/main/java/org/opensearch/bootstrap/OpenSearchUncaughtExceptionHandler.java
@@ -41,6 +41,11 @@
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 
+/**
+ * UncaughtException Handler used during bootstrapping
+ *
+ * @opensearch.internal
+ */
 class OpenSearchUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
     private static final Logger logger = LogManager.getLogger(OpenSearchUncaughtExceptionHandler.class);
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/Security.java b/server/src/main/java/org/opensearch/bootstrap/Security.java
index b3f4339f3e386..39614a786df82 100644
--- a/server/src/main/java/org/opensearch/bootstrap/Security.java
+++ b/server/src/main/java/org/opensearch/bootstrap/Security.java
@@ -116,6 +116,8 @@
  * </pre>
  * See <a href="https://docs.oracle.com/javase/7/docs/technotes/guides/security/troubleshooting-security.html">
  * Troubleshooting Security</a> for information.
+ *
+ * @opensearch.internal
  */
 final class Security {
     /** no instantiation */
diff --git a/server/src/main/java/org/opensearch/bootstrap/Spawner.java b/server/src/main/java/org/opensearch/bootstrap/Spawner.java
index c5e7171946790..47d4ae4f05a50 100644
--- a/server/src/main/java/org/opensearch/bootstrap/Spawner.java
+++ b/server/src/main/java/org/opensearch/bootstrap/Spawner.java
@@ -33,7 +33,7 @@
 package org.opensearch.bootstrap;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.plugins.Platforms;
 import org.opensearch.plugins.PluginInfo;
@@ -51,6 +51,8 @@
 
 /**
  * Spawns native module controller processes if present. Will only work prior to a system call filter being installed.
+ *
+ * @opensearch.internal
  */
 final class Spawner implements Closeable {
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/StartupException.java b/server/src/main/java/org/opensearch/bootstrap/StartupException.java
index 735e8cfd287af..9ad89ab518006 100644
--- a/server/src/main/java/org/opensearch/bootstrap/StartupException.java
+++ b/server/src/main/java/org/opensearch/bootstrap/StartupException.java
@@ -44,6 +44,8 @@
  * "reasonably". This means limits on stacktrace frames and
  * cleanup for guice, and some guidance about consulting full
  * logs for the whole exception.
+ *
+ * @opensearch.internal
  */
 // TODO: remove this when guice is removed, and exceptions are cleaned up
 // this is horrible, but its what we must do
diff --git a/server/src/main/java/org/opensearch/bootstrap/SystemCallFilter.java b/server/src/main/java/org/opensearch/bootstrap/SystemCallFilter.java
index 8e179de9c28df..6347c37a7c7a5 100644
--- a/server/src/main/java/org/opensearch/bootstrap/SystemCallFilter.java
+++ b/server/src/main/java/org/opensearch/bootstrap/SystemCallFilter.java
@@ -43,7 +43,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -102,6 +102,8 @@
  *      https://reverse.put.as/wp-content/uploads/2011/06/The-Apple-Sandbox-BHDC2011-Paper.pdf</a>
  * @see <a href="https://docs.oracle.com/cd/E23824_01/html/821-1456/prbac-2.html">
  *      https://docs.oracle.com/cd/E23824_01/html/821-1456/prbac-2.html</a>
+ *
+ * @opensearch.internal
  */
 // not an example of how to write code!!!
 final class SystemCallFilter {
@@ -257,6 +259,8 @@ static class Arch {
         Map<String, Arch> m = new HashMap<>();
         m.put("amd64", new Arch(0xC000003E, 0x3FFFFFFF, 57, 58, 59, 322, 317));
         m.put("aarch64", new Arch(0xC00000B7, 0xFFFFFFFF, 1079, 1071, 221, 281, 277));
+        m.put("s390x", new Arch(0x80000016, 0xFFFFFFFF, 2, 190, 11, 354, 348));
+        m.put("ppc64le", new Arch(0xC0000015, 0xFFFFFFFF, 2, 189, 11, 362, 358));
         ARCHITECTURES = Collections.unmodifiableMap(m);
     }
 
diff --git a/server/src/main/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParser.java b/server/src/main/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParser.java
new file mode 100644
index 0000000000000..65b50344b8e3a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParser.java
@@ -0,0 +1,176 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.bootstrap.jvm;
+
+import org.opensearch.common.Nullable;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.UncheckedIOException;
+import java.lang.Runtime.Version;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+/**
+ * Parses the list of JVM versions which should be denied to run Opensearch engine with due to discovered
+ * issues or flaws.
+ *
+ * @opensearch.internal
+ */
+public class DenyJvmVersionsParser {
+    /**
+     * Provides the reason for the denial
+     *
+     * @opensearch.internal
+     */
+    public interface VersionPredicate extends Predicate<Version> {
+        String getReason();
+    }
+
+    private static class SingleVersion implements VersionPredicate {
+        final private Version version;
+        final private String reason;
+
+        public SingleVersion(Version version, String reason) {
+            this.version = version;
+            this.reason = reason;
+        }
+
+        @Override
+        public boolean test(Version v) {
+            return version.compareTo(v) == 0;
+        }
+
+        @Override
+        public String getReason() {
+            return reason;
+        }
+    }
+
+    private static class VersionRange implements VersionPredicate {
+        private Version lower;
+        private boolean lowerIncluded;
+        private Version upper;
+        private boolean upperIncluded;
+        private String reason;
+
+        public VersionRange(@Nullable Version lower, boolean lowerIncluded, @Nullable Version upper, boolean upperIncluded, String reason) {
+            this.lower = lower;
+            this.lowerIncluded = lowerIncluded;
+            this.upper = upper;
+            this.upperIncluded = upperIncluded;
+            this.reason = reason;
+        }
+
+        @Override
+        public boolean test(Version v) {
+            if (lower != null) {
+                int compare = lower.compareTo(v);
+                if (compare > 0 || (compare == 0 && lowerIncluded != true)) {
+                    return false;
+                }
+            }
+
+            if (upper != null) {
+                int compare = upper.compareTo(v);
+                if (compare < 0 || (compare == 0 && upperIncluded != true)) {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        @Override
+        public String getReason() {
+            return reason;
+        }
+    }
+
+    public static Collection<VersionPredicate> getDeniedJvmVersions() {
+        try (
+            final InputStreamReader in = new InputStreamReader(
+                DenyJvmVersionsParser.class.getResourceAsStream("deny-jvm-versions.txt"),
+                StandardCharsets.UTF_8
+            )
+        ) {
+            try (final BufferedReader reader = new BufferedReader(in)) {
+                return reader.lines()
+                    .map(String::trim)
+                    // filter empty lines
+                    .filter(line -> line.isEmpty() == false)
+                    // filter out all comments
+                    .filter(line -> line.startsWith("//") == false)
+                    .map(DenyJvmVersionsParser::parse)
+                    .collect(Collectors.toList());
+            }
+        } catch (final IOException ex) {
+            throw new UncheckedIOException("Unable to read the list of denied JVM versions", ex);
+        }
+    }
+
+    /**
+     * Parse individual line from the list of denied JVM versions. Some version and version range examples are:
+     *  <ul>
+     *     <li>11.0.2: "... reason ..."             - version 11.0.2</li>
+     *     <li>[11.0.2, 11.0.14): "... reason ..."  - versions 11.0.2.2 (included) to 11.0.14 (not included)</li>
+     *     <li>[11.0.2, 11.0.14]: "... reason ..."  - versions 11.0.2 to 11.0.14 (both included)</li>
+     *     <li>[11.0.2,): "... reason ..."          - versions 11.0.2 and higher</li>
+     *  </ul>
+     * @param line line to parse
+     * @return version or version range predicate
+     */
+    static VersionPredicate parse(String line) {
+        final String[] parts = Arrays.stream(line.split("[:]", 2)).map(String::trim).toArray(String[]::new);
+
+        if (parts.length != 2) {
+            throw new IllegalArgumentException("Unable to parse JVM version or version range: " + line);
+        }
+
+        final String versionOrRange = parts[0];
+        final String reason = parts[1];
+
+        // dealing with version range here
+        if (versionOrRange.startsWith("[") == true || versionOrRange.startsWith("(") == true) {
+            if (versionOrRange.endsWith("]") == false && versionOrRange.endsWith(")") == false) {
+                throw new IllegalArgumentException("Unable to parse JVM version range: " + versionOrRange);
+            }
+
+            final boolean lowerIncluded = versionOrRange.startsWith("[");
+            final boolean upperIncluded = versionOrRange.endsWith("]");
+
+            final String[] range = Arrays.stream(versionOrRange.substring(1, versionOrRange.length() - 1).split("[,]", 2))
+                .map(String::trim)
+                .toArray(String[]::new);
+
+            if (range.length != 2) {
+                throw new IllegalArgumentException("Unable to parse JVM version range: " + versionOrRange);
+            }
+
+            Version lower = null;
+            if (range[0].isEmpty() == false && range[0].equals("*") == false) {
+                lower = Version.parse(range[0]);
+            }
+
+            Version upper = null;
+            if (range[1].isEmpty() == false && range[1].equals("*") == false) {
+                upper = Version.parse(range[1]);
+            }
+
+            return new VersionRange(lower, lowerIncluded, upper, upperIncluded, reason);
+        } else {
+            // this is just a single version
+            return new SingleVersion(Version.parse(versionOrRange), reason);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/bootstrap/jvm/package-info.java b/server/src/main/java/org/opensearch/bootstrap/jvm/package-info.java
new file mode 100644
index 0000000000000..e171e705a29f7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/bootstrap/jvm/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** jvm specific bootstrapping */
+package org.opensearch.bootstrap.jvm;
diff --git a/server/src/main/java/org/opensearch/bootstrap/package-info.java b/server/src/main/java/org/opensearch/bootstrap/package-info.java
new file mode 100644
index 0000000000000..a1761d8d38315
--- /dev/null
+++ b/server/src/main/java/org/opensearch/bootstrap/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The bootstrap module implementing OpenSearch bootstrap operations.
+ */
+package org.opensearch.bootstrap;
diff --git a/server/src/main/java/org/opensearch/cli/CommandLoggingConfigurator.java b/server/src/main/java/org/opensearch/cli/CommandLoggingConfigurator.java
index 1705e9ebdd4b9..8918725472160 100644
--- a/server/src/main/java/org/opensearch/cli/CommandLoggingConfigurator.java
+++ b/server/src/main/java/org/opensearch/cli/CommandLoggingConfigurator.java
@@ -39,6 +39,8 @@
 /**
  * Holder class for method to configure logging without OpenSearch configuration files for use in CLI tools that will not read such
  * files.
+ *
+ * @opensearch.internal
  */
 public final class CommandLoggingConfigurator {
 
diff --git a/server/src/main/java/org/opensearch/cli/EnvironmentAwareCommand.java b/server/src/main/java/org/opensearch/cli/EnvironmentAwareCommand.java
index e85af87213fd0..10c59ef673050 100644
--- a/server/src/main/java/org/opensearch/cli/EnvironmentAwareCommand.java
+++ b/server/src/main/java/org/opensearch/cli/EnvironmentAwareCommand.java
@@ -46,7 +46,11 @@
 import java.util.Locale;
 import java.util.Map;
 
-/** A cli command which requires an {@link org.opensearch.env.Environment} to use current paths and settings. */
+/**
+ * A cli command which requires an {@link org.opensearch.env.Environment} to use current paths and settings.
+ *
+ * @opensearch.internal
+ */
 public abstract class EnvironmentAwareCommand extends Command {
 
     private final OptionSpec<KeyValuePair> settingOption;
diff --git a/server/src/main/java/org/opensearch/cli/KeyStoreAwareCommand.java b/server/src/main/java/org/opensearch/cli/KeyStoreAwareCommand.java
index 404dacd504e8a..6cd266252b369 100644
--- a/server/src/main/java/org/opensearch/cli/KeyStoreAwareCommand.java
+++ b/server/src/main/java/org/opensearch/cli/KeyStoreAwareCommand.java
@@ -34,7 +34,7 @@
 
 import joptsimple.OptionSet;
 import org.opensearch.common.settings.KeyStoreWrapper;
-import org.opensearch.common.settings.SecureString;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 
 import java.io.IOException;
@@ -44,6 +44,8 @@
 /**
  * An {@link org.opensearch.cli.EnvironmentAwareCommand} that needs to access the opensearch keystore, possibly
  * decrypting it if it is password protected.
+ *
+ * @opensearch.internal
  */
 public abstract class KeyStoreAwareCommand extends EnvironmentAwareCommand {
     public KeyStoreAwareCommand(String description) {
diff --git a/server/src/main/java/org/opensearch/cli/LoggingAwareCommand.java b/server/src/main/java/org/opensearch/cli/LoggingAwareCommand.java
index 7aee5e3fa1f76..07a6b7d523a33 100644
--- a/server/src/main/java/org/opensearch/cli/LoggingAwareCommand.java
+++ b/server/src/main/java/org/opensearch/cli/LoggingAwareCommand.java
@@ -35,6 +35,8 @@
 /**
  * A command that is aware of logging. This class should be preferred over the base {@link Command} class for any CLI tools that depend on
  * core OpenSearch as they could directly or indirectly touch classes that touch logging and as such logging needs to be configured.
+ *
+ * @opensearch.internal
  */
 public abstract class LoggingAwareCommand extends Command {
 
diff --git a/server/src/main/java/org/opensearch/cli/LoggingAwareMultiCommand.java b/server/src/main/java/org/opensearch/cli/LoggingAwareMultiCommand.java
index 2354a4978aec9..8453ed05a12d3 100644
--- a/server/src/main/java/org/opensearch/cli/LoggingAwareMultiCommand.java
+++ b/server/src/main/java/org/opensearch/cli/LoggingAwareMultiCommand.java
@@ -36,6 +36,8 @@
  * A multi-command that is aware of logging. This class should be preferred over the base {@link MultiCommand} class for any CLI tools that
  * depend on core OpenSearch as they could directly or indirectly touch classes that touch logging and as such logging needs to be
  * configured.
+ *
+ * @opensearch.internal
  */
 public abstract class LoggingAwareMultiCommand extends MultiCommand {
 
diff --git a/server/src/main/java/org/opensearch/cli/package-info.java b/server/src/main/java/org/opensearch/cli/package-info.java
new file mode 100644
index 0000000000000..8e9f9f6360870
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cli/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The command line interface module.
+ */
+package org.opensearch.cli;
diff --git a/server/src/main/java/org/opensearch/client/AdminClient.java b/server/src/main/java/org/opensearch/client/AdminClient.java
index 995466ba5746c..1a5a39be4241a 100644
--- a/server/src/main/java/org/opensearch/client/AdminClient.java
+++ b/server/src/main/java/org/opensearch/client/AdminClient.java
@@ -32,12 +32,16 @@
 
 package org.opensearch.client;
 
+import org.opensearch.common.annotation.PublicApi;
+
 /**
  * Administrative actions/operations against the cluster or the indices.
  *
- *
  * @see org.opensearch.client.Client#admin()
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface AdminClient {
 
     /**
diff --git a/server/src/main/java/org/opensearch/client/Client.java b/server/src/main/java/org/opensearch/client/Client.java
index bca68834ca3cf..f4ae383249f61 100644
--- a/server/src/main/java/org/opensearch/client/Client.java
+++ b/server/src/main/java/org/opensearch/client/Client.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.admin.indices.segments.IndicesSegmentResponse;
+import org.opensearch.action.admin.indices.segments.PitSegmentsRequest;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.bulk.BulkRequestBuilder;
 import org.opensearch.action.bulk.BulkResponse;
@@ -58,6 +58,12 @@
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollRequestBuilder;
 import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.GetAllPitNodesRequest;
+import org.opensearch.action.search.GetAllPitNodesResponse;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchRequestBuilder;
 import org.opensearch.action.search.MultiSearchResponse;
@@ -76,10 +82,13 @@
 import org.opensearch.action.update.UpdateRequestBuilder;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.Map;
 
@@ -87,13 +96,16 @@
  * A client provides a one stop interface for performing actions/operations against the cluster.
  * <p>
  * All operations performed are asynchronous by nature. Each action/operation has two flavors, the first
- * simply returns an {@link org.opensearch.action.ActionFuture}, while the second accepts an
+ * simply returns an {@link ActionFuture}, while the second accepts an
  * {@link ActionListener}.
  * <p>
  * A client can be retrieved from a started {@link org.opensearch.node.Node}.
  *
  * @see org.opensearch.node.Node#client()
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface Client extends OpenSearchClient, Releasable {
 
     Setting<String> CLIENT_TYPE_SETTING_S = new Setting<>("client.type", "node", (s) -> {
@@ -323,6 +335,26 @@ public interface Client extends OpenSearchClient, Releasable {
      */
     SearchScrollRequestBuilder prepareSearchScroll(String scrollId);
 
+    /**
+     * Create point in time for one or more indices
+     */
+    void createPit(CreatePitRequest createPITRequest, ActionListener<CreatePitResponse> listener);
+
+    /**
+     * Delete one or more point in time contexts
+     */
+    void deletePits(DeletePitRequest deletePITRequest, ActionListener<DeletePitResponse> listener);
+
+    /**
+     * Get all active point in time searches
+     */
+    void getAllPits(GetAllPitNodesRequest getAllPitNodesRequest, ActionListener<GetAllPitNodesResponse> listener);
+
+    /**
+     * Get information of segments of one or more PITs
+     */
+    void pitSegments(PitSegmentsRequest pitSegmentsRequest, ActionListener<IndicesSegmentResponse> listener);
+
     /**
      * Performs multiple search requests.
      */
diff --git a/server/src/main/java/org/opensearch/client/ClusterAdminClient.java b/server/src/main/java/org/opensearch/client/ClusterAdminClient.java
index 1088b85ae271f..05f09c1a6e661 100644
--- a/server/src/main/java/org/opensearch/client/ClusterAdminClient.java
+++ b/server/src/main/java/org/opensearch/client/ClusterAdminClient.java
@@ -32,11 +32,18 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainRequest;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainRequestBuilder;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionResponse;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequestBuilder;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -62,6 +69,11 @@
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageRequest;
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageRequestBuilder;
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageResponse;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreResponse;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequest;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequestBuilder;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequest;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequestBuilder;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryResponse;
@@ -84,6 +96,15 @@
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequestBuilder;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequestBuilder;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
@@ -130,16 +151,26 @@
 import org.opensearch.action.ingest.SimulatePipelineRequest;
 import org.opensearch.action.ingest.SimulatePipelineRequestBuilder;
 import org.opensearch.action.ingest.SimulatePipelineResponse;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineResponse;
+import org.opensearch.action.search.PutSearchPipelineRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaType;
 
 /**
  * Administrative actions/operations against indices.
  *
  * @see AdminClient#cluster()
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface ClusterAdminClient extends OpenSearchClient {
 
     /**
@@ -289,6 +320,10 @@ public interface ClusterAdminClient extends OpenSearchClient {
      */
     NodesStatsRequestBuilder prepareNodesStats(String... nodesIds);
 
+    void remoteStoreStats(RemoteStoreStatsRequest request, ActionListener<RemoteStoreStatsResponse> listener);
+
+    RemoteStoreStatsRequestBuilder prepareRemoteStoreStats(String index, String shardId);
+
     /**
      * Returns top N hot-threads samples per node. The hot-threads are only
      * sampled for the node ids specified in the request. Nodes usage of the
@@ -575,6 +610,11 @@ public interface ClusterAdminClient extends OpenSearchClient {
      */
     void restoreSnapshot(RestoreSnapshotRequest request, ActionListener<RestoreSnapshotResponse> listener);
 
+    /**
+     * Restores from remote store.
+     */
+    void restoreRemoteStore(RestoreRemoteStoreRequest request, ActionListener<RestoreRemoteStoreResponse> listener);
+
     /**
      * Restores a snapshot.
      */
@@ -631,7 +671,7 @@ public interface ClusterAdminClient extends OpenSearchClient {
     /**
      * Stores an ingest pipeline
      */
-    PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, XContentType xContentType);
+    PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, MediaType mediaType);
 
     /**
      * Deletes a stored ingest pipeline
@@ -681,7 +721,7 @@ public interface ClusterAdminClient extends OpenSearchClient {
     /**
      * Simulates an ingest pipeline
      */
-    SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, XContentType xContentType);
+    SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, MediaType mediaType);
 
     /**
      * Explain the allocation of a shard
@@ -782,4 +822,124 @@ public interface ClusterAdminClient extends OpenSearchClient {
      * Delete specified dangling indices.
      */
     ActionFuture<AcknowledgedResponse> deleteDanglingIndex(DeleteDanglingIndexRequest request);
+
+    /**
+     * Updates weights for weighted round-robin search routing policy.
+     */
+    ActionFuture<ClusterPutWeightedRoutingResponse> putWeightedRouting(ClusterPutWeightedRoutingRequest request);
+
+    /**
+     * Updates weights for weighted round-robin search routing policy.
+     */
+    void putWeightedRouting(ClusterPutWeightedRoutingRequest request, ActionListener<ClusterPutWeightedRoutingResponse> listener);
+
+    /**
+     * Updates weights for weighted round-robin search routing policy.
+     */
+    ClusterPutWeightedRoutingRequestBuilder prepareWeightedRouting();
+
+    /**
+     * Gets weights for weighted round-robin search routing policy.
+     */
+    ActionFuture<ClusterGetWeightedRoutingResponse> getWeightedRouting(ClusterGetWeightedRoutingRequest request);
+
+    /**
+     * Gets weights for weighted round-robin search routing policy.
+     */
+    void getWeightedRouting(ClusterGetWeightedRoutingRequest request, ActionListener<ClusterGetWeightedRoutingResponse> listener);
+
+    /**
+     * Gets weights for weighted round-robin search routing policy.
+     */
+    ClusterGetWeightedRoutingRequestBuilder prepareGetWeightedRouting();
+
+    /**
+     * Deletes weights for weighted round-robin search routing policy.
+     */
+    ActionFuture<ClusterDeleteWeightedRoutingResponse> deleteWeightedRouting(ClusterDeleteWeightedRoutingRequest request);
+
+    /**
+     * Deletes weights for weighted round-robin search routing policy.
+     */
+    void deleteWeightedRouting(ClusterDeleteWeightedRoutingRequest request, ActionListener<ClusterDeleteWeightedRoutingResponse> listener);
+
+    /**
+     * Deletes weights for weighted round-robin search routing policy.
+     */
+    ClusterDeleteWeightedRoutingRequestBuilder prepareDeleteWeightedRouting();
+
+    /**
+     * Decommission awareness attribute
+     */
+    ActionFuture<DecommissionResponse> decommission(DecommissionRequest request);
+
+    /**
+     * Decommission awareness attribute
+     */
+    void decommission(DecommissionRequest request, ActionListener<DecommissionResponse> listener);
+
+    /**
+     * Decommission awareness attribute
+     */
+    DecommissionRequestBuilder prepareDecommission(DecommissionRequest request);
+
+    /**
+     * Get Decommissioned attribute
+     */
+    ActionFuture<GetDecommissionStateResponse> getDecommissionState(GetDecommissionStateRequest request);
+
+    /**
+     * Get Decommissioned attribute
+     */
+    void getDecommissionState(GetDecommissionStateRequest request, ActionListener<GetDecommissionStateResponse> listener);
+
+    /**
+     * Get Decommissioned attribute
+     */
+    GetDecommissionStateRequestBuilder prepareGetDecommissionState();
+
+    /**
+     * Deletes the decommission metadata.
+     */
+    ActionFuture<DeleteDecommissionStateResponse> deleteDecommissionState(DeleteDecommissionStateRequest request);
+
+    /**
+     * Deletes the decommission metadata.
+     */
+    void deleteDecommissionState(DeleteDecommissionStateRequest request, ActionListener<DeleteDecommissionStateResponse> listener);
+
+    /**
+     * Deletes the decommission metadata.
+     */
+    DeleteDecommissionStateRequestBuilder prepareDeleteDecommissionRequest();
+
+    /**
+     * Stores a search pipeline
+     */
+    void putSearchPipeline(PutSearchPipelineRequest request, ActionListener<AcknowledgedResponse> listener);
+
+    /**
+     * Stores a search pipeline
+     */
+    ActionFuture<AcknowledgedResponse> putSearchPipeline(PutSearchPipelineRequest request);
+
+    /**
+     * Returns a stored search pipeline
+     */
+    void getSearchPipeline(GetSearchPipelineRequest request, ActionListener<GetSearchPipelineResponse> listener);
+
+    /**
+     * Returns a stored search pipeline
+     */
+    ActionFuture<GetSearchPipelineResponse> getSearchPipeline(GetSearchPipelineRequest request);
+
+    /**
+     * Deletes a stored search pipeline
+     */
+    void deleteSearchPipeline(DeleteSearchPipelineRequest request, ActionListener<AcknowledgedResponse> listener);
+
+    /**
+     * Deletes a stored search pipeline
+     */
+    ActionFuture<AcknowledgedResponse> deleteSearchPipeline(DeleteSearchPipelineRequest request);
 }
diff --git a/server/src/main/java/org/opensearch/client/FilterClient.java b/server/src/main/java/org/opensearch/client/FilterClient.java
index 4d7bf2ed30b00..2ce7146a794cb 100644
--- a/server/src/main/java/org/opensearch/client/FilterClient.java
+++ b/server/src/main/java/org/opensearch/client/FilterClient.java
@@ -31,18 +31,20 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.support.AbstractClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.threadpool.ThreadPool;
 
 /**
  * A {@link Client} that contains another {@link Client} which it
  * uses as its basic source, possibly transforming the requests / responses along the
  * way or providing additional functionality.
+ *
+ * @opensearch.internal
  */
 public abstract class FilterClient extends AbstractClient {
 
diff --git a/server/src/main/java/org/opensearch/client/IndicesAdminClient.java b/server/src/main/java/org/opensearch/client/IndicesAdminClient.java
index 7f51b8af19e4b..20dab1caa36c4 100644
--- a/server/src/main/java/org/opensearch/client/IndicesAdminClient.java
+++ b/server/src/main/java/org/opensearch/client/IndicesAdminClient.java
@@ -32,12 +32,8 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequestBuilder;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistRequestBuilder;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistResponse;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequestBuilder;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
@@ -60,9 +56,6 @@
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsRequest;
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsRequestBuilder;
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsResponse;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsRequest;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsRequestBuilder;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsResponse;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.admin.indices.flush.FlushRequestBuilder;
 import org.opensearch.action.admin.indices.flush.FlushResponse;
@@ -92,6 +85,9 @@
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.admin.indices.refresh.RefreshRequestBuilder;
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequest;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequestBuilder;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction;
 import org.opensearch.action.admin.indices.rollover.RolloverRequest;
 import org.opensearch.action.admin.indices.rollover.RolloverRequestBuilder;
@@ -132,12 +128,18 @@
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.cluster.metadata.IndexMetadata.APIBlock;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * Administrative actions/operations against indices.
  *
  * @see AdminClient#indices()
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface IndicesAdminClient extends OpenSearchClient {
 
     /**
@@ -163,34 +165,6 @@ public interface IndicesAdminClient extends OpenSearchClient {
      */
     IndicesExistsRequestBuilder prepareExists(String... indices);
 
-    /**
-     * Types exists.
-     *
-     * @deprecated Types are deprecated and are in the process of being removed.
-     * @param request The types exists request
-     * @return The result future
-     */
-    @Deprecated
-    ActionFuture<TypesExistsResponse> typesExists(TypesExistsRequest request);
-
-    /**
-     * Types exists.
-     *
-     * @deprecated Types are deprecated and are in the process of being removed.
-     * @param request  The types exists
-     * @param listener A listener to be notified with a result
-     */
-    @Deprecated
-    void typesExists(TypesExistsRequest request, ActionListener<TypesExistsResponse> listener);
-
-    /**
-     * Types exists.
-     *
-     * @deprecated Types are deprecated and are in the process of being removed.
-     */
-    @Deprecated
-    TypesExistsRequestBuilder prepareTypesExists(String... index);
-
     /**
      * Indices stats.
      */
@@ -216,11 +190,26 @@ public interface IndicesAdminClient extends OpenSearchClient {
      */
     void recoveries(RecoveryRequest request, ActionListener<RecoveryResponse> listener);
 
+    /**
+     *Indices segment replication
+     */
+    ActionFuture<SegmentReplicationStatsResponse> segmentReplicationStats(SegmentReplicationStatsRequest request);
+
+    /**
+     *Indices segment replication
+     */
+    void segmentReplicationStats(SegmentReplicationStatsRequest request, ActionListener<SegmentReplicationStatsResponse> listener);
+
     /**
      * Indices recoveries
      */
     RecoveryRequestBuilder prepareRecoveries(String... indices);
 
+    /**
+     * Indices segment replication
+     */
+    SegmentReplicationStatsRequestBuilder prepareSegmentReplicationStats(String... indices);
+
     /**
      * The segments of one or more indices.
      *
@@ -595,26 +584,6 @@ public interface IndicesAdminClient extends OpenSearchClient {
      */
     GetAliasesRequestBuilder prepareGetAliases(String... aliases);
 
-    /**
-     * Allows to check to existence of aliases from indices.
-     */
-    AliasesExistRequestBuilder prepareAliasesExist(String... aliases);
-
-    /**
-     * Check to existence of index aliases.
-     *
-     * @param request The result future
-     */
-    ActionFuture<AliasesExistResponse> aliasesExist(GetAliasesRequest request);
-
-    /**
-     * Check the existence of specified index aliases.
-     *
-     * @param request  The index aliases request
-     * @param listener A listener to be notified with a result
-     */
-    void aliasesExist(GetAliasesRequest request, ActionListener<AliasesExistResponse> listener);
-
     /**
      * Get index metadata for particular indices.
      *
diff --git a/server/src/main/java/org/opensearch/client/OpenSearchClient.java b/server/src/main/java/org/opensearch/client/OpenSearchClient.java
index 9b092c98aa5f5..22b6436c93033 100644
--- a/server/src/main/java/org/opensearch/client/OpenSearchClient.java
+++ b/server/src/main/java/org/opensearch/client/OpenSearchClient.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.threadpool.ThreadPool;
 
+/**
+ * Interface for an OpenSearch client implementation
+ *
+ * @opensearch.internal
+ */
 public interface OpenSearchClient {
 
     /**
diff --git a/server/src/main/java/org/opensearch/client/OriginSettingClient.java b/server/src/main/java/org/opensearch/client/OriginSettingClient.java
index acb6352b06185..1b0e08cc489c4 100644
--- a/server/src/main/java/org/opensearch/client/OriginSettingClient.java
+++ b/server/src/main/java/org/opensearch/client/OriginSettingClient.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ContextPreservingActionListener;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 
 import java.util.function.Supplier;
 
@@ -46,6 +46,8 @@
  * {@link ThreadContext#stashWithOrigin origin} set to a particular
  * value and calls its {@linkplain ActionListener} in its original
  * {@link ThreadContext}.
+ *
+ * @opensearch.internal
  */
 public final class OriginSettingClient extends FilterClient {
 
diff --git a/server/src/main/java/org/opensearch/client/ParentTaskAssigningClient.java b/server/src/main/java/org/opensearch/client/ParentTaskAssigningClient.java
index 444f0ea778b05..17fda113b2fdc 100644
--- a/server/src/main/java/org/opensearch/client/ParentTaskAssigningClient.java
+++ b/server/src/main/java/org/opensearch/client/ParentTaskAssigningClient.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 /**
  * A {@linkplain Client} that sets the parent task on all requests that it makes. Use this to conveniently implement actions that cause
  * many other actions.
+ *
+ * @opensearch.internal
  */
 public class ParentTaskAssigningClient extends FilterClient {
     private final TaskId parentTask;
diff --git a/server/src/main/java/org/opensearch/client/Requests.java b/server/src/main/java/org/opensearch/client/Requests.java
index d89f55a37a9cf..3607590826007 100644
--- a/server/src/main/java/org/opensearch/client/Requests.java
+++ b/server/src/main/java/org/opensearch/client/Requests.java
@@ -32,6 +32,9 @@
 
 package org.opensearch.client;
 
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
@@ -47,6 +50,9 @@
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteRequest;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
@@ -76,9 +82,13 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 
 /**
  * A handy one stop shop for creating requests (make sure to import static this class).
+ *
+ * @opensearch.internal
  */
 public class Requests {
 
@@ -90,7 +100,7 @@ public class Requests {
     /**
      * The default content type to use to generate source documents when indexing.
      */
-    public static XContentType INDEX_CONTENT_TYPE = XContentType.JSON;
+    public static MediaType INDEX_CONTENT_TYPE = MediaTypeRegistry.JSON;
 
     public static IndexRequest indexRequest() {
         return new IndexRequest();
@@ -546,4 +556,56 @@ public static DeleteSnapshotRequest deleteSnapshotRequest(String repository, Str
     public static SnapshotsStatusRequest snapshotsStatusRequest(String repository) {
         return new SnapshotsStatusRequest(repository);
     }
+
+    /**
+     * Updates weights for weighted round-robin search routing policy
+     *
+     * @return update weight request
+     */
+    public static ClusterPutWeightedRoutingRequest putWeightedRoutingRequest(String attributeName) {
+        return new ClusterPutWeightedRoutingRequest(attributeName);
+    }
+
+    /**
+     * Gets weights for weighted round-robin search routing policy
+     *
+     * @return get weight request
+     */
+    public static ClusterGetWeightedRoutingRequest getWeightedRoutingRequest(String attributeName) {
+        return new ClusterGetWeightedRoutingRequest(attributeName);
+    }
+
+    /**
+     * Deletes weights for weighted round-robin search routing policy
+     *
+     * @return delete weight request
+     */
+    public static ClusterDeleteWeightedRoutingRequest deleteWeightedRoutingRequest(String attributeName) {
+        return new ClusterDeleteWeightedRoutingRequest(attributeName);
+    }
+
+    /**
+     * Creates a new decommission request.
+     *
+     * @return returns put decommission request
+     */
+    public static DecommissionRequest decommissionRequest() {
+        return new DecommissionRequest();
+    }
+
+    /**
+     * Get decommissioned attribute from metadata
+     *
+     * @return returns get decommission request
+     */
+    public static GetDecommissionStateRequest getDecommissionStateRequest() {
+        return new GetDecommissionStateRequest();
+    }
+
+    /**
+     * Creates a new delete decommission request.
+     */
+    public static DeleteDecommissionStateRequest deleteDecommissionStateRequest() {
+        return new DeleteDecommissionStateRequest();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/client/node/NodeClient.java b/server/src/main/java/org/opensearch/client/node/NodeClient.java
index bda7cdca91015..6e1bb6ce79349 100644
--- a/server/src/main/java/org/opensearch/client/node/NodeClient.java
+++ b/server/src/main/java/org/opensearch/client/node/NodeClient.java
@@ -32,30 +32,32 @@
 
 package org.opensearch.client.node;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.client.Client;
 import org.opensearch.client.support.AbstractClient;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskListener;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterService;
 
-import java.util.Map;
 import java.util.function.Supplier;
 
 /**
  * Client that executes actions on the local node.
+ *
+ * @opensearch.internal
  */
 public class NodeClient extends AbstractClient {
 
-    private Map<ActionType, TransportAction> actions;
+    private DynamicActionRegistry actionRegistry;
     /**
      * The id of the local {@link DiscoveryNode}. Useful for generating task ids from tasks returned by
      * {@link #executeLocally(ActionType, ActionRequest, TaskListener)}.
@@ -69,12 +71,12 @@ public NodeClient(Settings settings, ThreadPool threadPool) {
     }
 
     public void initialize(
-        Map<ActionType, TransportAction> actions,
+        DynamicActionRegistry actionRegistry,
         Supplier<String> localNodeId,
         RemoteClusterService remoteClusterService,
         NamedWriteableRegistry namedWriteableRegistry
     ) {
-        this.actions = actions;
+        this.actionRegistry = actionRegistry;
         this.localNodeId = localNodeId;
         this.remoteClusterService = remoteClusterService;
         this.namedWriteableRegistry = namedWriteableRegistry;
@@ -135,10 +137,10 @@ public String getLocalNodeId() {
     private <Request extends ActionRequest, Response extends ActionResponse> TransportAction<Request, Response> transportAction(
         ActionType<Response> action
     ) {
-        if (actions == null) {
+        if (actionRegistry == null) {
             throw new IllegalStateException("NodeClient has not been initialized");
         }
-        TransportAction<Request, Response> transportAction = actions.get(action);
+        TransportAction<Request, Response> transportAction = (TransportAction<Request, Response>) actionRegistry.get(action);
         if (transportAction == null) {
             throw new IllegalStateException("failed to find action [" + action + "] to execute");
         }
diff --git a/server/src/main/java/org/opensearch/client/node/package-info.java b/server/src/main/java/org/opensearch/client/node/package-info.java
new file mode 100644
index 0000000000000..0a3be1fad6bf0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/client/node/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The node client module allowing to easily perform actions/operations at node level.
+ */
+package org.opensearch.client.node;
diff --git a/server/src/main/java/org/opensearch/client/package-info.java b/server/src/main/java/org/opensearch/client/package-info.java
index 24c744803a151..abfd9a9119971 100644
--- a/server/src/main/java/org/opensearch/client/package-info.java
+++ b/server/src/main/java/org/opensearch/client/package-info.java
@@ -25,12 +25,12 @@
  * under the License.
  */
 
-/**
- * The client module allowing to easily perform actions/operations.
- */
 /*
  * Modifications Copyright OpenSearch Contributors. See
  * GitHub history for details.
  */
 
+/**
+ * The client module allowing to easily perform actions/operations.
+ */
 package org.opensearch.client;
diff --git a/server/src/main/java/org/opensearch/client/support/AbstractClient.java b/server/src/main/java/org/opensearch/client/support/AbstractClient.java
index a37d293ee5dd2..786bfa38bb19c 100644
--- a/server/src/main/java/org/opensearch/client/support/AbstractClient.java
+++ b/server/src/main/java/org/opensearch/client/support/AbstractClient.java
@@ -34,15 +34,24 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainAction;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainRequest;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainRequestBuilder;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionAction;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequestBuilder;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionResponse;
 import org.opensearch.action.admin.cluster.health.ClusterHealthAction;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequestBuilder;
@@ -77,6 +86,13 @@
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageRequest;
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageRequestBuilder;
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageResponse;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreAction;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreResponse;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsAction;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequest;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequestBuilder;
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryAction;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequest;
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequestBuilder;
@@ -107,6 +123,18 @@
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequestBuilder;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterAddWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingResponse;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotAction;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequestBuilder;
@@ -154,9 +182,6 @@
 import org.opensearch.action.admin.indices.alias.IndicesAliasesAction;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequestBuilder;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistAction;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistRequestBuilder;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistResponse;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesAction;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequestBuilder;
@@ -192,10 +217,6 @@
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsRequest;
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsRequestBuilder;
 import org.opensearch.action.admin.indices.exists.indices.IndicesExistsResponse;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsAction;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsRequest;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsRequestBuilder;
-import org.opensearch.action.admin.indices.exists.types.TypesExistsResponse;
 import org.opensearch.action.admin.indices.flush.FlushAction;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.admin.indices.flush.FlushRequestBuilder;
@@ -235,6 +256,10 @@
 import org.opensearch.action.admin.indices.refresh.RefreshRequest;
 import org.opensearch.action.admin.indices.refresh.RefreshRequestBuilder;
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsAction;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequest;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequestBuilder;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction;
 import org.opensearch.action.admin.indices.rollover.RolloverAction;
 import org.opensearch.action.admin.indices.rollover.RolloverRequest;
@@ -244,6 +269,8 @@
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsAction;
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequest;
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequestBuilder;
+import org.opensearch.action.admin.indices.segments.PitSegmentsAction;
+import org.opensearch.action.admin.indices.segments.PitSegmentsRequest;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsAction;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsRequest;
 import org.opensearch.action.admin.indices.settings.get.GetSettingsRequestBuilder;
@@ -331,10 +358,26 @@
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollRequestBuilder;
 import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.DeleteSearchPipelineAction;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.GetAllPitNodesRequest;
+import org.opensearch.action.search.GetAllPitNodesResponse;
+import org.opensearch.action.search.GetAllPitsAction;
+import org.opensearch.action.search.GetSearchPipelineAction;
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.action.search.GetSearchPipelineResponse;
 import org.opensearch.action.search.MultiSearchAction;
 import org.opensearch.action.search.MultiSearchRequest;
 import org.opensearch.action.search.MultiSearchRequestBuilder;
 import org.opensearch.action.search.MultiSearchResponse;
+import org.opensearch.action.search.PutSearchPipelineAction;
+import org.opensearch.action.search.PutSearchPipelineRequest;
 import org.opensearch.action.search.SearchAction;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchRequestBuilder;
@@ -364,15 +407,23 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.metadata.IndexMetadata.APIBlock;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.Map;
 
+/**
+ * Base client used to create concrete client implementations
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractClient implements Client {
 
     protected final Logger logger;
@@ -576,6 +627,26 @@ public SearchScrollRequestBuilder prepareSearchScroll(String scrollId) {
         return new SearchScrollRequestBuilder(this, SearchScrollAction.INSTANCE, scrollId);
     }
 
+    @Override
+    public void createPit(final CreatePitRequest createPITRequest, final ActionListener<CreatePitResponse> listener) {
+        execute(CreatePitAction.INSTANCE, createPITRequest, listener);
+    }
+
+    @Override
+    public void deletePits(final DeletePitRequest deletePITRequest, final ActionListener<DeletePitResponse> listener) {
+        execute(DeletePitAction.INSTANCE, deletePITRequest, listener);
+    }
+
+    @Override
+    public void getAllPits(final GetAllPitNodesRequest getAllPitNodesRequest, final ActionListener<GetAllPitNodesResponse> listener) {
+        execute(GetAllPitsAction.INSTANCE, getAllPitNodesRequest, listener);
+    }
+
+    @Override
+    public void pitSegments(final PitSegmentsRequest request, final ActionListener<IndicesSegmentResponse> listener) {
+        execute(PitSegmentsAction.INSTANCE, request, listener);
+    }
+
     @Override
     public ActionFuture<MultiSearchResponse> multiSearch(MultiSearchRequest request) {
         return execute(MultiSearchAction.INSTANCE, request);
@@ -820,6 +891,23 @@ public NodesStatsRequestBuilder prepareNodesStats(String... nodesIds) {
             return new NodesStatsRequestBuilder(this, NodesStatsAction.INSTANCE).setNodesIds(nodesIds);
         }
 
+        @Override
+        public void remoteStoreStats(final RemoteStoreStatsRequest request, final ActionListener<RemoteStoreStatsResponse> listener) {
+            execute(RemoteStoreStatsAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public RemoteStoreStatsRequestBuilder prepareRemoteStoreStats(String index, String shardId) {
+            RemoteStoreStatsRequestBuilder remoteStoreStatsRequestBuilder = new RemoteStoreStatsRequestBuilder(
+                this,
+                RemoteStoreStatsAction.INSTANCE
+            ).setIndices(index);
+            if (shardId != null) {
+                remoteStoreStatsRequestBuilder.setShards(shardId);
+            }
+            return remoteStoreStatsRequestBuilder;
+        }
+
         @Override
         public ActionFuture<NodesUsageResponse> nodesUsage(final NodesUsageRequest request) {
             return execute(NodesUsageAction.INSTANCE, request);
@@ -1095,6 +1183,11 @@ public void restoreSnapshot(RestoreSnapshotRequest request, ActionListener<Resto
             execute(RestoreSnapshotAction.INSTANCE, request, listener);
         }
 
+        @Override
+        public void restoreRemoteStore(RestoreRemoteStoreRequest request, ActionListener<RestoreRemoteStoreResponse> listener) {
+            execute(RestoreRemoteStoreAction.INSTANCE, request, listener);
+        }
+
         @Override
         public RestoreSnapshotRequestBuilder prepareRestoreSnapshot(String repository, String snapshot) {
             return new RestoreSnapshotRequestBuilder(this, RestoreSnapshotAction.INSTANCE, repository, snapshot);
@@ -1131,8 +1224,8 @@ public ActionFuture<AcknowledgedResponse> putPipeline(PutPipelineRequest request
         }
 
         @Override
-        public PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, XContentType xContentType) {
-            return new PutPipelineRequestBuilder(this, PutPipelineAction.INSTANCE, id, source, xContentType);
+        public PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, MediaType mediaType) {
+            return new PutPipelineRequestBuilder(this, PutPipelineAction.INSTANCE, id, source, mediaType);
         }
 
         @Override
@@ -1181,8 +1274,8 @@ public ActionFuture<SimulatePipelineResponse> simulatePipeline(SimulatePipelineR
         }
 
         @Override
-        public SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, XContentType xContentType) {
-            return new SimulatePipelineRequestBuilder(this, SimulatePipelineAction.INSTANCE, source, xContentType);
+        public SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, MediaType mediaType) {
+            return new SimulatePipelineRequestBuilder(this, SimulatePipelineAction.INSTANCE, source, mediaType);
         }
 
         @Override
@@ -1235,6 +1328,60 @@ public ActionFuture<AcknowledgedResponse> deleteDanglingIndex(DeleteDanglingInde
             return execute(DeleteDanglingIndexAction.INSTANCE, request);
         }
 
+        @Override
+        public ActionFuture<ClusterPutWeightedRoutingResponse> putWeightedRouting(ClusterPutWeightedRoutingRequest request) {
+            return execute(ClusterAddWeightedRoutingAction.INSTANCE, request);
+        }
+
+        @Override
+        public void putWeightedRouting(
+            ClusterPutWeightedRoutingRequest request,
+            ActionListener<ClusterPutWeightedRoutingResponse> listener
+        ) {
+            execute(ClusterAddWeightedRoutingAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ClusterPutWeightedRoutingRequestBuilder prepareWeightedRouting() {
+            return new ClusterPutWeightedRoutingRequestBuilder(this, ClusterAddWeightedRoutingAction.INSTANCE);
+        }
+
+        @Override
+        public ActionFuture<ClusterGetWeightedRoutingResponse> getWeightedRouting(ClusterGetWeightedRoutingRequest request) {
+            return execute(ClusterGetWeightedRoutingAction.INSTANCE, request);
+        }
+
+        @Override
+        public void getWeightedRouting(
+            ClusterGetWeightedRoutingRequest request,
+            ActionListener<ClusterGetWeightedRoutingResponse> listener
+        ) {
+            execute(ClusterGetWeightedRoutingAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ClusterGetWeightedRoutingRequestBuilder prepareGetWeightedRouting() {
+            return new ClusterGetWeightedRoutingRequestBuilder(this, ClusterGetWeightedRoutingAction.INSTANCE);
+        }
+
+        @Override
+        public ActionFuture<ClusterDeleteWeightedRoutingResponse> deleteWeightedRouting(ClusterDeleteWeightedRoutingRequest request) {
+            return execute(ClusterDeleteWeightedRoutingAction.INSTANCE, request);
+        }
+
+        @Override
+        public void deleteWeightedRouting(
+            ClusterDeleteWeightedRoutingRequest request,
+            ActionListener<ClusterDeleteWeightedRoutingResponse> listener
+        ) {
+            execute(ClusterDeleteWeightedRoutingAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ClusterDeleteWeightedRoutingRequestBuilder prepareDeleteWeightedRouting() {
+            return new ClusterDeleteWeightedRoutingRequestBuilder(this, ClusterDeleteWeightedRoutingAction.INSTANCE);
+        }
+
         @Override
         public void deleteDanglingIndex(DeleteDanglingIndexRequest request, ActionListener<AcknowledgedResponse> listener) {
             execute(DeleteDanglingIndexAction.INSTANCE, request, listener);
@@ -1285,6 +1432,84 @@ public DeleteStoredScriptRequestBuilder prepareDeleteStoredScript() {
         public DeleteStoredScriptRequestBuilder prepareDeleteStoredScript(String id) {
             return prepareDeleteStoredScript().setId(id);
         }
+
+        @Override
+        public ActionFuture<DecommissionResponse> decommission(DecommissionRequest request) {
+            return execute(DecommissionAction.INSTANCE, request);
+        }
+
+        @Override
+        public void decommission(DecommissionRequest request, ActionListener<DecommissionResponse> listener) {
+            execute(DecommissionAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public DecommissionRequestBuilder prepareDecommission(DecommissionRequest request) {
+            return new DecommissionRequestBuilder(this, DecommissionAction.INSTANCE, request);
+        }
+
+        @Override
+        public ActionFuture<GetDecommissionStateResponse> getDecommissionState(GetDecommissionStateRequest request) {
+            return execute(GetDecommissionStateAction.INSTANCE, request);
+        }
+
+        @Override
+        public void getDecommissionState(GetDecommissionStateRequest request, ActionListener<GetDecommissionStateResponse> listener) {
+            execute(GetDecommissionStateAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public GetDecommissionStateRequestBuilder prepareGetDecommissionState() {
+            return new GetDecommissionStateRequestBuilder(this, GetDecommissionStateAction.INSTANCE);
+        }
+
+        @Override
+        public ActionFuture<DeleteDecommissionStateResponse> deleteDecommissionState(DeleteDecommissionStateRequest request) {
+            return execute(DeleteDecommissionStateAction.INSTANCE, request);
+        }
+
+        @Override
+        public void deleteDecommissionState(
+            DeleteDecommissionStateRequest request,
+            ActionListener<DeleteDecommissionStateResponse> listener
+        ) {
+            execute(DeleteDecommissionStateAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public DeleteDecommissionStateRequestBuilder prepareDeleteDecommissionRequest() {
+            return new DeleteDecommissionStateRequestBuilder(this, DeleteDecommissionStateAction.INSTANCE);
+        }
+
+        @Override
+        public void putSearchPipeline(PutSearchPipelineRequest request, ActionListener<AcknowledgedResponse> listener) {
+            execute(PutSearchPipelineAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ActionFuture<AcknowledgedResponse> putSearchPipeline(PutSearchPipelineRequest request) {
+            return execute(PutSearchPipelineAction.INSTANCE, request);
+        }
+
+        @Override
+        public void getSearchPipeline(GetSearchPipelineRequest request, ActionListener<GetSearchPipelineResponse> listener) {
+            execute(GetSearchPipelineAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ActionFuture<GetSearchPipelineResponse> getSearchPipeline(GetSearchPipelineRequest request) {
+            return execute(GetSearchPipelineAction.INSTANCE, request);
+        }
+
+        @Override
+        public void deleteSearchPipeline(DeleteSearchPipelineRequest request, ActionListener<AcknowledgedResponse> listener) {
+            execute(DeleteSearchPipelineAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public ActionFuture<AcknowledgedResponse> deleteSearchPipeline(DeleteSearchPipelineRequest request) {
+            return execute(DeleteSearchPipelineAction.INSTANCE, request);
+        }
     }
 
     static class IndicesAdmin implements IndicesAdminClient {
@@ -1332,22 +1557,6 @@ public IndicesExistsRequestBuilder prepareExists(String... indices) {
             return new IndicesExistsRequestBuilder(this, IndicesExistsAction.INSTANCE, indices);
         }
 
-        @Deprecated
-        @Override
-        public ActionFuture<TypesExistsResponse> typesExists(TypesExistsRequest request) {
-            return execute(TypesExistsAction.INSTANCE, request);
-        }
-
-        @Override
-        public void typesExists(TypesExistsRequest request, ActionListener<TypesExistsResponse> listener) {
-            execute(TypesExistsAction.INSTANCE, request, listener);
-        }
-
-        @Override
-        public TypesExistsRequestBuilder prepareTypesExists(String... index) {
-            return new TypesExistsRequestBuilder(this, TypesExistsAction.INSTANCE, index);
-        }
-
         @Override
         public ActionFuture<AcknowledgedResponse> aliases(final IndicesAliasesRequest request) {
             return execute(IndicesAliasesAction.INSTANCE, request);
@@ -1383,21 +1592,6 @@ public ActionFuture<ClearIndicesCacheResponse> clearCache(final ClearIndicesCach
             return execute(ClearIndicesCacheAction.INSTANCE, request);
         }
 
-        @Override
-        public void aliasesExist(GetAliasesRequest request, ActionListener<AliasesExistResponse> listener) {
-            execute(AliasesExistAction.INSTANCE, request, listener);
-        }
-
-        @Override
-        public ActionFuture<AliasesExistResponse> aliasesExist(GetAliasesRequest request) {
-            return execute(AliasesExistAction.INSTANCE, request);
-        }
-
-        @Override
-        public AliasesExistRequestBuilder prepareAliasesExist(String... aliases) {
-            return new AliasesExistRequestBuilder(this, AliasesExistAction.INSTANCE, aliases);
-        }
-
         @Override
         public ActionFuture<GetIndexResponse> getIndex(GetIndexRequest request) {
             return execute(GetIndexAction.INSTANCE, request);
@@ -1643,6 +1837,24 @@ public RecoveryRequestBuilder prepareRecoveries(String... indices) {
             return new RecoveryRequestBuilder(this, RecoveryAction.INSTANCE).setIndices(indices);
         }
 
+        @Override
+        public ActionFuture<SegmentReplicationStatsResponse> segmentReplicationStats(final SegmentReplicationStatsRequest request) {
+            return execute(SegmentReplicationStatsAction.INSTANCE, request);
+        }
+
+        @Override
+        public void segmentReplicationStats(
+            final SegmentReplicationStatsRequest request,
+            final ActionListener<SegmentReplicationStatsResponse> listener
+        ) {
+            execute(SegmentReplicationStatsAction.INSTANCE, request, listener);
+        }
+
+        @Override
+        public SegmentReplicationStatsRequestBuilder prepareSegmentReplicationStats(String... indices) {
+            return new SegmentReplicationStatsRequestBuilder(this, SegmentReplicationStatsAction.INSTANCE).setIndices(indices);
+        }
+
         @Override
         public ActionFuture<IndicesSegmentResponse> segments(final IndicesSegmentsRequest request) {
             return execute(IndicesSegmentsAction.INSTANCE, request);
diff --git a/server/src/main/java/org/opensearch/client/support/package-info.java b/server/src/main/java/org/opensearch/client/support/package-info.java
new file mode 100644
index 0000000000000..637f7f03101aa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/client/support/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * The Abstract client for implementing new client types.
+ */
+package org.opensearch.client.support;
diff --git a/server/src/main/java/org/opensearch/client/transport/NoNodeAvailableException.java b/server/src/main/java/org/opensearch/client/transport/NoNodeAvailableException.java
index a4ffe2102037e..75dbd90275367 100644
--- a/server/src/main/java/org/opensearch/client/transport/NoNodeAvailableException.java
+++ b/server/src/main/java/org/opensearch/client/transport/NoNodeAvailableException.java
@@ -33,13 +33,15 @@
 package org.opensearch.client.transport;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * An exception indicating no node is available to perform the operation.
+ *
+ * @opensearch.internal
  */
 public class NoNodeAvailableException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/client/transport/package-info.java b/server/src/main/java/org/opensearch/client/transport/package-info.java
new file mode 100644
index 0000000000000..a775d93350b19
--- /dev/null
+++ b/server/src/main/java/org/opensearch/client/transport/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Transport Client support classes.
+ */
+package org.opensearch.client.transport;
diff --git a/server/src/main/java/org/opensearch/cluster/AbstractDiffable.java b/server/src/main/java/org/opensearch/cluster/AbstractDiffable.java
index 7b95545e58101..74af3472433ba 100644
--- a/server/src/main/java/org/opensearch/cluster/AbstractDiffable.java
+++ b/server/src/main/java/org/opensearch/cluster/AbstractDiffable.java
@@ -33,14 +33,16 @@
 package org.opensearch.cluster;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Abstract diffable object with simple diffs implementation that sends the entire object if object has changed or
  * nothing if object remained the same.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractDiffable<T extends Diffable<T>> implements Diffable<T> {
 
@@ -64,6 +66,11 @@ public static <T extends Diffable<T>> Diff<T> readDiffFrom(Reader<T> reader, Str
         return (Diff<T>) EMPTY;
     }
 
+    /**
+     * A complete diff.
+     *
+     * @opensearch.internal
+     */
     private static class CompleteDiff<T extends Diffable<T>> implements Diff<T> {
 
         @Nullable
diff --git a/server/src/main/java/org/opensearch/cluster/AbstractNamedDiffable.java b/server/src/main/java/org/opensearch/cluster/AbstractNamedDiffable.java
index 43ff74f30a249..49837aea83708 100644
--- a/server/src/main/java/org/opensearch/cluster/AbstractNamedDiffable.java
+++ b/server/src/main/java/org/opensearch/cluster/AbstractNamedDiffable.java
@@ -34,15 +34,17 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Abstract diffable object with simple diffs implementation that sends the entire object if object has changed or
  * nothing is object remained the same. Comparing to AbstractDiffable, this class also works with NamedWriteables
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractNamedDiffable<T extends NamedDiffable<T>> implements Diffable<T>, NamedWriteable {
 
@@ -60,6 +62,11 @@ public static <T extends NamedDiffable<T>> NamedDiff<T> readDiffFrom(Class<? ext
         return new CompleteNamedDiff<>(tClass, name, in);
     }
 
+    /**
+     * A complete named diff.
+     *
+     * @opensearch.internal
+     */
     private static class CompleteNamedDiff<T extends NamedDiffable<T>> implements NamedDiff<T> {
 
         @Nullable
diff --git a/server/src/main/java/org/opensearch/cluster/AckedClusterStateTaskListener.java b/server/src/main/java/org/opensearch/cluster/AckedClusterStateTaskListener.java
index 0f6531fb09be9..482087be1c8eb 100644
--- a/server/src/main/java/org/opensearch/cluster/AckedClusterStateTaskListener.java
+++ b/server/src/main/java/org/opensearch/cluster/AckedClusterStateTaskListener.java
@@ -35,6 +35,11 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Listener when cluster state task is acknowledged
+ *
+ * @opensearch.internal
+ */
 public interface AckedClusterStateTaskListener extends ClusterStateTaskListener {
 
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/AckedClusterStateUpdateTask.java b/server/src/main/java/org/opensearch/cluster/AckedClusterStateUpdateTask.java
index 82ea05274d0d1..dfca0edcfbf5f 100644
--- a/server/src/main/java/org/opensearch/cluster/AckedClusterStateUpdateTask.java
+++ b/server/src/main/java/org/opensearch/cluster/AckedClusterStateUpdateTask.java
@@ -31,16 +31,18 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ack.AckedRequest;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * An extension interface to {@link ClusterStateUpdateTask} that allows to be notified when
  * all the nodes have acknowledged a cluster state update request
+ *
+ * @opensearch.internal
  */
 public abstract class AckedClusterStateUpdateTask<Response> extends ClusterStateUpdateTask implements AckedClusterStateTaskListener {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterChangedEvent.java b/server/src/main/java/org/opensearch/cluster/ClusterChangedEvent.java
index db54016a61f6d..fab104142e5bb 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterChangedEvent.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterChangedEvent.java
@@ -32,27 +32,27 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.cluster.metadata.IndexGraveyard;
 import org.opensearch.cluster.metadata.IndexGraveyard.IndexGraveyardDiff;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.core.index.Index;
 import org.opensearch.gateway.GatewayService;
-import org.opensearch.index.Index;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
 /**
  * An event received by the local node, signaling that the cluster state has changed.
+ *
+ * @opensearch.internal
  */
 public class ClusterChangedEvent {
 
@@ -127,8 +127,7 @@ public List<String> indicesCreated() {
             return Collections.emptyList();
         }
         List<String> created = null;
-        for (ObjectCursor<String> cursor : state.metadata().indices().keys()) {
-            String index = cursor.value;
+        for (final String index : state.metadata().indices().keySet()) {
             if (!previousState.metadata().hasIndex(index)) {
                 if (created == null) {
                     created = new ArrayList<>();
@@ -168,20 +167,20 @@ public boolean metadataChanged() {
      */
     public Set<String> changedCustomMetadataSet() {
         Set<String> result = new HashSet<>();
-        ImmutableOpenMap<String, Metadata.Custom> currentCustoms = state.metadata().customs();
-        ImmutableOpenMap<String, Metadata.Custom> previousCustoms = previousState.metadata().customs();
+        Map<String, Metadata.Custom> currentCustoms = state.metadata().customs();
+        Map<String, Metadata.Custom> previousCustoms = previousState.metadata().customs();
         if (currentCustoms.equals(previousCustoms) == false) {
-            for (ObjectObjectCursor<String, Metadata.Custom> currentCustomMetadata : currentCustoms) {
+            for (Map.Entry<String, Metadata.Custom> currentCustomMetadata : currentCustoms.entrySet()) {
                 // new custom md added or existing custom md changed
-                if (previousCustoms.containsKey(currentCustomMetadata.key) == false
-                    || currentCustomMetadata.value.equals(previousCustoms.get(currentCustomMetadata.key)) == false) {
-                    result.add(currentCustomMetadata.key);
+                if (previousCustoms.containsKey(currentCustomMetadata.getKey()) == false
+                    || currentCustomMetadata.getValue().equals(previousCustoms.get(currentCustomMetadata.getKey())) == false) {
+                    result.add(currentCustomMetadata.getKey());
                 }
             }
             // existing custom md deleted
-            for (ObjectObjectCursor<String, Metadata.Custom> previousCustomMetadata : previousCustoms) {
-                if (currentCustoms.containsKey(previousCustomMetadata.key) == false) {
-                    result.add(previousCustomMetadata.key);
+            for (Map.Entry<String, Metadata.Custom> previousCustomMetadata : previousCustoms.entrySet()) {
+                if (currentCustoms.containsKey(previousCustomMetadata.getKey()) == false) {
+                    result.add(previousCustomMetadata.getKey());
                 }
             }
         }
@@ -211,8 +210,18 @@ public boolean blocksChanged() {
     /**
      * Returns <code>true</code> iff the local node is the mater node of the cluster.
      */
+    public boolean localNodeClusterManager() {
+        return state.nodes().isLocalNodeElectedClusterManager();
+    }
+
+    /**
+     * Returns <code>true</code> iff the local node is the mater node of the cluster.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #localNodeClusterManager()}
+     */
+    @Deprecated
     public boolean localNodeMaster() {
-        return state.nodes().isLocalNodeElectedMaster();
+        return localNodeClusterManager();
     }
 
     /**
@@ -248,7 +257,7 @@ public boolean nodesChanged() {
      * Determines whether or not the current cluster state represents an entirely
      * new cluster, either when a node joins a cluster for the first time or when
      * the node receives a cluster state update from a brand new cluster (different
-     * UUID from the previous cluster), which will happen when a master node is
+     * UUID from the previous cluster), which will happen when a cluster-manager node is
      * elected that has never been part of the cluster before.
      */
     public boolean isNewCluster() {
@@ -260,10 +269,10 @@ public boolean isNewCluster() {
     // Get the deleted indices by comparing the index metadatas in the previous and new cluster states.
     // If an index exists in the previous cluster state, but not in the new cluster state, it must have been deleted.
     private List<Index> indicesDeletedFromClusterState() {
-        // If the new cluster state has a new cluster UUID, the likely scenario is that a node was elected
-        // master that has had its data directory wiped out, in which case we don't want to delete the indices and lose data;
+        // If the new cluster state has a new cluster UUID, the likely scenario is that a node was elected cluster-manager
+        // that has had its data directory wiped out, in which case we don't want to delete the indices and lose data;
         // rather we want to import them as dangling indices instead. So we check here if the cluster UUID differs from the previous
-        // cluster UUID, in which case, we don't want to delete indices that the master erroneously believes shouldn't exist.
+        // cluster UUID, in which case, we don't want to delete indices that the cluster-manager erroneously believes shouldn't exist.
         // See test DiscoveryWithServiceDisruptionsIT.testIndicesDeleted()
         // See discussion on https://github.com/elastic/elasticsearch/pull/9952 and
         // https://github.com/elastic/elasticsearch/issues/11665
@@ -274,8 +283,7 @@ private List<Index> indicesDeletedFromClusterState() {
         final Metadata previousMetadata = previousState.metadata();
         final Metadata currentMetadata = state.metadata();
 
-        for (ObjectCursor<IndexMetadata> cursor : previousMetadata.indices().values()) {
-            IndexMetadata index = cursor.value;
+        for (final IndexMetadata index : previousMetadata.indices().values()) {
             IndexMetadata current = currentMetadata.index(index.getIndex());
             if (current == null) {
                 if (deleted == null) {
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterInfo.java b/server/src/main/java/org/opensearch/cluster/ClusterInfo.java
index 19e026c570c74..8f0937b17bbc0 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterInfo.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterInfo.java
@@ -32,40 +32,44 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.ObjectHashSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
+import org.opensearch.Version;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.store.StoreStats;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * ClusterInfo is an object representing a map of nodes to {@link DiskUsage}
  * and a map of shard ids to shard sizes, see
  * <code>InternalClusterInfoService.shardIdentifierFromRouting(String)</code>
  * for the key used in the shardSizes map
+ *
+ * @opensearch.internal
  */
 public class ClusterInfo implements ToXContentFragment, Writeable {
-    private final ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage;
-    private final ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsage;
-    final ImmutableOpenMap<String, Long> shardSizes;
+    private final Map<String, DiskUsage> leastAvailableSpaceUsage;
+    private final Map<String, DiskUsage> mostAvailableSpaceUsage;
+    final Map<String, Long> shardSizes;  // pkg-private for testing only
     public static final ClusterInfo EMPTY = new ClusterInfo();
-    final ImmutableOpenMap<ShardRouting, String> routingToDataPath;
-    final ImmutableOpenMap<NodeAndPath, ReservedSpace> reservedSpace;
+    final Map<ShardRouting, String> routingToDataPath;
+    final Map<NodeAndPath, ReservedSpace> reservedSpace;
+    final Map<String, FileCacheStats> nodeFileCacheStats;
 
     protected ClusterInfo() {
-        this(ImmutableOpenMap.of(), ImmutableOpenMap.of(), ImmutableOpenMap.of(), ImmutableOpenMap.of(), ImmutableOpenMap.of());
+        this(Map.of(), Map.of(), Map.of(), Map.of(), Map.of(), Map.of());
     }
 
     /**
@@ -79,17 +83,19 @@ protected ClusterInfo() {
      * @see #shardIdentifierFromRouting
      */
     public ClusterInfo(
-        ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage,
-        ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsage,
-        ImmutableOpenMap<String, Long> shardSizes,
-        ImmutableOpenMap<ShardRouting, String> routingToDataPath,
-        ImmutableOpenMap<NodeAndPath, ReservedSpace> reservedSpace
+        final Map<String, DiskUsage> leastAvailableSpaceUsage,
+        final Map<String, DiskUsage> mostAvailableSpaceUsage,
+        final Map<String, Long> shardSizes,
+        final Map<ShardRouting, String> routingToDataPath,
+        final Map<NodeAndPath, ReservedSpace> reservedSpace,
+        final Map<String, FileCacheStats> nodeFileCacheStats
     ) {
         this.leastAvailableSpaceUsage = leastAvailableSpaceUsage;
         this.shardSizes = shardSizes;
         this.mostAvailableSpaceUsage = mostAvailableSpaceUsage;
         this.routingToDataPath = routingToDataPath;
         this.reservedSpace = reservedSpace;
+        this.nodeFileCacheStats = nodeFileCacheStats;
     }
 
     public ClusterInfo(StreamInput in) throws IOException {
@@ -101,51 +107,50 @@ public ClusterInfo(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
             reservedSpaceMap = in.readMap(NodeAndPath::new, ReservedSpace::new);
         } else {
-            reservedSpaceMap = org.opensearch.common.collect.Map.of();
+            reservedSpaceMap = Map.of();
         }
 
-        ImmutableOpenMap.Builder<String, DiskUsage> leastBuilder = ImmutableOpenMap.builder();
-        this.leastAvailableSpaceUsage = leastBuilder.putAll(leastMap).build();
-        ImmutableOpenMap.Builder<String, DiskUsage> mostBuilder = ImmutableOpenMap.builder();
-        this.mostAvailableSpaceUsage = mostBuilder.putAll(mostMap).build();
-        ImmutableOpenMap.Builder<String, Long> sizeBuilder = ImmutableOpenMap.builder();
-        this.shardSizes = sizeBuilder.putAll(sizeMap).build();
-        ImmutableOpenMap.Builder<ShardRouting, String> routingBuilder = ImmutableOpenMap.builder();
-        this.routingToDataPath = routingBuilder.putAll(routingMap).build();
-        ImmutableOpenMap.Builder<NodeAndPath, ReservedSpace> reservedSpaceBuilder = ImmutableOpenMap.builder();
-        this.reservedSpace = reservedSpaceBuilder.putAll(reservedSpaceMap).build();
+        this.leastAvailableSpaceUsage = Collections.unmodifiableMap(leastMap);
+        this.mostAvailableSpaceUsage = Collections.unmodifiableMap(mostMap);
+        this.shardSizes = Collections.unmodifiableMap(sizeMap);
+        this.routingToDataPath = Collections.unmodifiableMap(routingMap);
+        this.reservedSpace = Collections.unmodifiableMap(reservedSpaceMap);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            this.nodeFileCacheStats = in.readMap(StreamInput::readString, FileCacheStats::new);
+        } else {
+            this.nodeFileCacheStats = Map.of();
+        }
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeVInt(this.leastAvailableSpaceUsage.size());
-        for (ObjectObjectCursor<String, DiskUsage> c : this.leastAvailableSpaceUsage) {
-            out.writeString(c.key);
-            c.value.writeTo(out);
-        }
+        out.writeMap(this.leastAvailableSpaceUsage, StreamOutput::writeString, (o, v) -> v.writeTo(o));
         out.writeMap(this.mostAvailableSpaceUsage, StreamOutput::writeString, (o, v) -> v.writeTo(o));
         out.writeMap(this.shardSizes, StreamOutput::writeString, (o, v) -> out.writeLong(v == null ? -1 : v));
         out.writeMap(this.routingToDataPath, (o, k) -> k.writeTo(o), StreamOutput::writeString);
         if (out.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
-            out.writeMap(this.reservedSpace);
+            out.writeMap(this.reservedSpace, (o, v) -> v.writeTo(o), (o, v) -> v.writeTo(o));
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeMap(this.nodeFileCacheStats, StreamOutput::writeString, (o, v) -> v.writeTo(o));
         }
     }
 
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject("nodes");
         {
-            for (ObjectObjectCursor<String, DiskUsage> c : this.leastAvailableSpaceUsage) {
-                builder.startObject(c.key);
+            for (Map.Entry<String, DiskUsage> c : this.leastAvailableSpaceUsage.entrySet()) {
+                builder.startObject(c.getKey());
                 { // node
-                    builder.field("node_name", c.value.getNodeName());
+                    builder.field("node_name", c.getValue().getNodeName());
                     builder.startObject("least_available");
                     {
-                        c.value.toShortXContent(builder);
+                        c.getValue().toShortXContent(builder);
                     }
                     builder.endObject(); // end "least_available"
                     builder.startObject("most_available");
                     {
-                        DiskUsage most = this.mostAvailableSpaceUsage.get(c.key);
+                        DiskUsage most = this.mostAvailableSpaceUsage.get(c.getKey());
                         if (most != null) {
                             most.toShortXContent(builder);
                         }
@@ -158,26 +163,26 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.endObject(); // end "nodes"
         builder.startObject("shard_sizes");
         {
-            for (ObjectObjectCursor<String, Long> c : this.shardSizes) {
-                builder.humanReadableField(c.key + "_bytes", c.key, new ByteSizeValue(c.value));
+            for (Map.Entry<String, Long> c : this.shardSizes.entrySet()) {
+                builder.humanReadableField(c.getKey() + "_bytes", c.getKey(), new ByteSizeValue(c.getValue()));
             }
         }
         builder.endObject(); // end "shard_sizes"
         builder.startObject("shard_paths");
         {
-            for (ObjectObjectCursor<ShardRouting, String> c : this.routingToDataPath) {
-                builder.field(c.key.toString(), c.value);
+            for (Map.Entry<ShardRouting, String> c : this.routingToDataPath.entrySet()) {
+                builder.field(c.getKey().toString(), c.getValue());
             }
         }
         builder.endObject(); // end "shard_paths"
         builder.startArray("reserved_sizes");
         {
-            for (ObjectObjectCursor<NodeAndPath, ReservedSpace> c : this.reservedSpace) {
+            for (Map.Entry<NodeAndPath, ReservedSpace> c : this.reservedSpace.entrySet()) {
                 builder.startObject();
                 {
-                    builder.field("node_id", c.key.nodeId);
-                    builder.field("path", c.key.path);
-                    c.value.toXContent(builder, params);
+                    builder.field("node_id", c.getKey().nodeId);
+                    builder.field("path", c.getKey().path);
+                    c.getValue().toXContent(builder, params);
                 }
                 builder.endObject(); // NodeAndPath
             }
@@ -190,16 +195,23 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
      * Returns a node id to disk usage mapping for the path that has the least available space on the node.
      * Note that this does not take account of reserved space: there may be another path with less available _and unreserved_ space.
      */
-    public ImmutableOpenMap<String, DiskUsage> getNodeLeastAvailableDiskUsages() {
-        return this.leastAvailableSpaceUsage;
+    public Map<String, DiskUsage> getNodeLeastAvailableDiskUsages() {
+        return Collections.unmodifiableMap(this.leastAvailableSpaceUsage);
     }
 
     /**
      * Returns a node id to disk usage mapping for the path that has the most available space on the node.
      * Note that this does not take account of reserved space: there may be another path with more available _and unreserved_ space.
      */
-    public ImmutableOpenMap<String, DiskUsage> getNodeMostAvailableDiskUsages() {
-        return this.mostAvailableSpaceUsage;
+    public Map<String, DiskUsage> getNodeMostAvailableDiskUsages() {
+        return Collections.unmodifiableMap(this.mostAvailableSpaceUsage);
+    }
+
+    /**
+     * Returns a node id to file cache stats mapping for the nodes that have search roles assigned to it.
+     */
+    public Map<String, FileCacheStats> getNodeFileCacheStats() {
+        return Collections.unmodifiableMap(this.nodeFileCacheStats);
     }
 
     /**
@@ -242,6 +254,8 @@ static String shardIdentifierFromRouting(ShardRouting shardRouting) {
 
     /**
      * Represents a data path on a node
+     *
+     * @opensearch.internal
      */
     public static class NodeAndPath implements Writeable {
         public final String nodeId;
@@ -279,34 +293,37 @@ public void writeTo(StreamOutput out) throws IOException {
 
     /**
      * Represents the total amount of "reserved" space on a particular data path, together with the set of shards considered.
+     *
+     * @opensearch.internal
      */
     public static class ReservedSpace implements Writeable {
 
-        public static final ReservedSpace EMPTY = new ReservedSpace(0, new ObjectHashSet<>());
+        public static final ReservedSpace EMPTY = new ReservedSpace(0, new HashSet<>());
 
         private final long total;
-        private final ObjectHashSet<ShardId> shardIds;
+        private final Set<ShardId> shardIds;
 
-        private ReservedSpace(long total, ObjectHashSet<ShardId> shardIds) {
+        private ReservedSpace(long total, Set<ShardId> shardIds) {
             this.total = total;
-            this.shardIds = shardIds;
+            this.shardIds = Collections.unmodifiableSet(shardIds);
         }
 
         ReservedSpace(StreamInput in) throws IOException {
             total = in.readVLong();
             final int shardIdCount = in.readVInt();
-            shardIds = new ObjectHashSet<>(shardIdCount);
+            Set<ShardId> shardIds = new HashSet<>(shardIdCount);
             for (int i = 0; i < shardIdCount; i++) {
                 shardIds.add(new ShardId(in));
             }
+            this.shardIds = Collections.unmodifiableSet(shardIds);
         }
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             out.writeVLong(total);
             out.writeVInt(shardIds.size());
-            for (ObjectCursor<ShardId> shardIdCursor : shardIds) {
-                shardIdCursor.value.writeTo(out);
+            for (final ShardId shardIdCursor : shardIds) {
+                shardIdCursor.writeTo(out);
             }
         }
 
@@ -335,16 +352,21 @@ void toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.field("total", total);
             builder.startArray("shards");
             {
-                for (ObjectCursor<ShardId> shardIdCursor : shardIds) {
-                    shardIdCursor.value.toXContent(builder, params);
+                for (final ShardId shardIdCursor : shardIds) {
+                    shardIdCursor.toXContent(builder, params);
                 }
             }
             builder.endArray(); // end "shards"
         }
 
+        /**
+         * Builder for Reserved Space.
+         *
+         * @opensearch.internal
+         */
         public static class Builder {
             private long total;
-            private ObjectHashSet<ShardId> shardIds = new ObjectHashSet<>();
+            private Set<ShardId> shardIds = new HashSet<>();
 
             public ReservedSpace build() {
                 assert shardIds != null : "already built";
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterInfoService.java b/server/src/main/java/org/opensearch/cluster/ClusterInfoService.java
index 03ef68fbd1c4d..50675d11003bb 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterInfoService.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterInfoService.java
@@ -36,6 +36,8 @@
 
 /**
  * Interface for a class used to gather information about a cluster periodically.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface ClusterInfoService {
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterManagerNodeChangePredicate.java b/server/src/main/java/org/opensearch/cluster/ClusterManagerNodeChangePredicate.java
new file mode 100644
index 0000000000000..b5c65dacb9542
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/ClusterManagerNodeChangePredicate.java
@@ -0,0 +1,71 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+
+import java.util.function.Predicate;
+
+/**
+ * Utility class to build a predicate that accepts cluster state changes
+ *
+ * @opensearch.internal
+ */
+public final class ClusterManagerNodeChangePredicate {
+
+    private ClusterManagerNodeChangePredicate() {
+
+    }
+
+    /**
+     * builds a predicate that will accept a cluster state only if it was generated after the current has
+     * (re-)joined the master
+     */
+    public static Predicate<ClusterState> build(ClusterState currentState) {
+        final long currentVersion = currentState.version();
+        final DiscoveryNode clusterManagerNode = currentState.nodes().getClusterManagerNode();
+        final String currentMasterId = clusterManagerNode == null ? null : clusterManagerNode.getEphemeralId();
+        return newState -> {
+            final DiscoveryNode newClusterManager = newState.nodes().getClusterManagerNode();
+            final boolean accept;
+            if (newClusterManager == null) {
+                accept = false;
+            } else if (newClusterManager.getEphemeralId().equals(currentMasterId) == false) {
+                accept = true;
+            } else {
+                accept = newState.version() > currentVersion;
+            }
+            return accept;
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterModule.java b/server/src/main/java/org/opensearch/cluster/ClusterModule.java
index c85691b80d7c3..bad881f8bda76 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterModule.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterModule.java
@@ -35,6 +35,7 @@
 import org.opensearch.cluster.action.index.MappingUpdatedAction;
 import org.opensearch.cluster.action.index.NodeMappingRefreshAction;
 import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
 import org.opensearch.cluster.metadata.ComponentTemplateMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplateMetadata;
 import org.opensearch.cluster.metadata.DataStreamMetadata;
@@ -48,6 +49,7 @@
 import org.opensearch.cluster.metadata.MetadataMappingService;
 import org.opensearch.cluster.metadata.MetadataUpdateSettingsService;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
 import org.opensearch.cluster.routing.DelayedAllocationService;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.ExistingShardsAllocator;
@@ -57,8 +59,8 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
-import org.opensearch.cluster.routing.allocation.decider.ConcurrentRecoveriesAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ConcurrentRebalanceAllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.ConcurrentRecoveriesAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.FilterAllocationDecider;
@@ -72,26 +74,28 @@
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.SnapshotInProgressAllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.TargetPoolAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.inject.AbstractModule;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.io.stream.Writeable.Reader;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.ingest.IngestMetadata;
 import org.opensearch.persistent.PersistentTasksCustomMetadata;
 import org.opensearch.persistent.PersistentTasksNodeService;
 import org.opensearch.plugins.ClusterPlugin;
 import org.opensearch.script.ScriptMetadata;
+import org.opensearch.search.pipeline.SearchPipelineMetadata;
 import org.opensearch.snapshots.SnapshotsInfoService;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskResultsService;
@@ -110,6 +114,8 @@
 
 /**
  * Configures classes and services that affect the entire cluster.
+ *
+ * @opensearch.internal
  */
 public class ClusterModule extends AbstractModule {
 
@@ -167,6 +173,7 @@ public static List<Entry> getNamedWriteables() {
         // Metadata
         registerMetadataCustom(entries, RepositoriesMetadata.TYPE, RepositoriesMetadata::new, RepositoriesMetadata::readDiffFrom);
         registerMetadataCustom(entries, IngestMetadata.TYPE, IngestMetadata::new, IngestMetadata::readDiffFrom);
+        registerMetadataCustom(entries, SearchPipelineMetadata.TYPE, SearchPipelineMetadata::new, SearchPipelineMetadata::readDiffFrom);
         registerMetadataCustom(entries, ScriptMetadata.TYPE, ScriptMetadata::new, ScriptMetadata::readDiffFrom);
         registerMetadataCustom(entries, IndexGraveyard.TYPE, IndexGraveyard::new, IndexGraveyard::readDiffFrom);
         registerMetadataCustom(
@@ -188,6 +195,13 @@ public static List<Entry> getNamedWriteables() {
             ComposableIndexTemplateMetadata::readDiffFrom
         );
         registerMetadataCustom(entries, DataStreamMetadata.TYPE, DataStreamMetadata::new, DataStreamMetadata::readDiffFrom);
+        registerMetadataCustom(entries, WeightedRoutingMetadata.TYPE, WeightedRoutingMetadata::new, WeightedRoutingMetadata::readDiffFrom);
+        registerMetadataCustom(
+            entries,
+            DecommissionAttributeMetadata.TYPE,
+            DecommissionAttributeMetadata::new,
+            DecommissionAttributeMetadata::readDiffFrom
+        );
         // Task Status (not Diffable)
         entries.add(new Entry(Task.Status.class, PersistentTasksNodeService.Status.NAME, PersistentTasksNodeService.Status::new));
         return entries;
@@ -210,13 +224,13 @@ public static List<Entry> getNamedWriteables() {
      */
     public static ClusterState filterCustomsForPre63Clients(ClusterState clusterState) {
         final ClusterState.Builder builder = ClusterState.builder(clusterState);
-        clusterState.customs().keysIt().forEachRemaining(name -> {
+        clusterState.customs().keySet().iterator().forEachRemaining(name -> {
             if (PRE_6_3_CLUSTER_CUSTOMS_WHITE_LIST.contains(name) == false) {
                 builder.removeCustom(name);
             }
         });
         final Metadata.Builder metaBuilder = Metadata.builder(clusterState.metadata());
-        clusterState.metadata().customs().keysIt().forEachRemaining(name -> {
+        clusterState.metadata().customs().keySet().iterator().forEachRemaining(name -> {
             if (PRE_6_3_METADATA_CUSTOMS_WHITE_LIST.contains(name) == false) {
                 metaBuilder.removeCustom(name);
             }
@@ -237,6 +251,13 @@ public static List<NamedXContentRegistry.Entry> getNamedXWriteables() {
         entries.add(
             new NamedXContentRegistry.Entry(Metadata.Custom.class, new ParseField(IngestMetadata.TYPE), IngestMetadata::fromXContent)
         );
+        entries.add(
+            new NamedXContentRegistry.Entry(
+                Metadata.Custom.class,
+                new ParseField(SearchPipelineMetadata.TYPE),
+                SearchPipelineMetadata::fromXContent
+            )
+        );
         entries.add(
             new NamedXContentRegistry.Entry(Metadata.Custom.class, new ParseField(ScriptMetadata.TYPE), ScriptMetadata::fromXContent)
         );
@@ -271,6 +292,20 @@ public static List<NamedXContentRegistry.Entry> getNamedXWriteables() {
                 DataStreamMetadata::fromXContent
             )
         );
+        entries.add(
+            new NamedXContentRegistry.Entry(
+                Metadata.Custom.class,
+                new ParseField(WeightedRoutingMetadata.TYPE),
+                WeightedRoutingMetadata::fromXContent
+            )
+        );
+        entries.add(
+            new NamedXContentRegistry.Entry(
+                Metadata.Custom.class,
+                new ParseField(DecommissionAttributeMetadata.TYPE),
+                DecommissionAttributeMetadata::fromXContent
+            )
+        );
         return entries;
     }
 
@@ -324,7 +359,7 @@ public static Collection<AllocationDecider> createAllocationDeciders(
         addAllocationDecider(deciders, new ConcurrentRebalanceAllocationDecider(settings, clusterSettings));
         addAllocationDecider(deciders, new ConcurrentRecoveriesAllocationDecider(settings, clusterSettings));
         addAllocationDecider(deciders, new EnableAllocationDecider(settings, clusterSettings));
-        addAllocationDecider(deciders, new NodeVersionAllocationDecider());
+        addAllocationDecider(deciders, new NodeVersionAllocationDecider(settings));
         addAllocationDecider(deciders, new SnapshotInProgressAllocationDecider());
         addAllocationDecider(deciders, new RestoreInProgressAllocationDecider());
         addAllocationDecider(deciders, new FilterAllocationDecider(settings, clusterSettings));
@@ -334,6 +369,7 @@ public static Collection<AllocationDecider> createAllocationDeciders(
         addAllocationDecider(deciders, new ShardsLimitAllocationDecider(settings, clusterSettings));
         addAllocationDecider(deciders, new AwarenessAllocationDecider(settings, clusterSettings));
         addAllocationDecider(deciders, new NodeLoadAwareAllocationDecider(settings, clusterSettings));
+        addAllocationDecider(deciders, new TargetPoolAllocationDecider());
 
         clusterPlugins.stream()
             .flatMap(p -> p.createAllocationDeciders(settings, clusterSettings).stream())
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterName.java b/server/src/main/java/org/opensearch/cluster/ClusterName.java
index 86b182c6f6c2d..44321f7de9395 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterName.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterName.java
@@ -32,16 +32,21 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.function.Predicate;
 
+/**
+ * Cluster Name
+ *
+ * @opensearch.internal
+ */
 public class ClusterName implements Writeable {
 
     public static final Setting<ClusterName> CLUSTER_NAME_SETTING = new Setting<>("cluster.name", "opensearch", (s) -> {
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterSettingsResponse.java b/server/src/main/java/org/opensearch/cluster/ClusterSettingsResponse.java
new file mode 100644
index 0000000000000..3dc764cb5d520
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/ClusterSettingsResponse.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * PluginSettings Response for Extensibility
+ *
+ * @opensearch.internal
+ */
+public class ClusterSettingsResponse extends TransportResponse {
+    private final Settings clusterSettings;
+
+    public ClusterSettingsResponse(ClusterService clusterService) {
+        this.clusterSettings = clusterService.getSettings();
+    }
+
+    public ClusterSettingsResponse(StreamInput in) throws IOException {
+        super(in);
+        this.clusterSettings = Settings.readSettingsFromStream(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        Settings.writeSettingsToStream(clusterSettings, out);
+    }
+
+    @Override
+    public String toString() {
+        return "ClusterSettingsResponse{" + "clusterSettings=" + clusterSettings + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ClusterSettingsResponse that = (ClusterSettingsResponse) o;
+        return Objects.equals(clusterSettings, that.clusterSettings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(clusterSettings);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterState.java b/server/src/main/java/org/opensearch/cluster/ClusterState.java
index 459c0b9502acf..1b87a60c2ccf5 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterState.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterState.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
@@ -50,28 +48,29 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.VersionedNamedWriteable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.VersionedNamedWriteable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.discovery.Discovery;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
+import java.util.Spliterators;
 import java.util.stream.StreamSupport;
 
 import static org.opensearch.cluster.coordination.Coordinator.ZEN1_BWC_TERM;
@@ -81,7 +80,7 @@
  * <p>
  * The cluster state object is immutable with the exception of the {@link RoutingNodes} structure, which is
  * built on demand from the {@link RoutingTable}.
- * The cluster state can be updated only on the master node. All updates are performed by on a
+ * The cluster state can be updated only on the cluster-manager node. All updates are performed by on a
  * single thread and controlled by the {@link ClusterService}. After every update the
  * {@link Discovery#publish} method publishes a new version of the cluster state to all other nodes in the
  * cluster. The actual publishing mechanism is delegated to the {@link Discovery#publish} method and depends on
@@ -97,6 +96,8 @@
  * make sure that the correct diffs are applied. If uuids don’t match, the {@link ClusterStateDiff#apply} method
  * throws the {@link IncompatibleClusterStateVersionException}, which causes the publishing mechanism to send
  * a full version of the cluster state to the node on which this exception was thrown.
+ *
+ * @opensearch.internal
  */
 public class ClusterState implements ToXContentFragment, Diffable<ClusterState> {
 
@@ -104,6 +105,8 @@ public class ClusterState implements ToXContentFragment, Diffable<ClusterState>
 
     /**
      * An interface that implementors use when a class requires a client to maybe have a feature.
+     *
+     * @opensearch.internal
      */
     public interface FeatureAware {
 
@@ -133,6 +136,11 @@ static <T extends VersionedNamedWriteable & FeatureAware> boolean shouldSerializ
 
     }
 
+    /**
+     * Custom cluster state.
+     *
+     * @opensearch.internal
+     */
     public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, FeatureAware {
 
         /**
@@ -163,13 +171,13 @@ default boolean isPrivate() {
 
     private final ClusterBlocks blocks;
 
-    private final ImmutableOpenMap<String, Custom> customs;
+    private final Map<String, Custom> customs;
 
     private final ClusterName clusterName;
 
     private final boolean wasReadFromDiff;
 
-    private final int minimumMasterNodesOnPublishingMaster;
+    private final int minimumClusterManagerNodesOnPublishingClusterManager;
 
     // built on demand
     private volatile RoutingNodes routingNodes;
@@ -197,8 +205,8 @@ public ClusterState(
         RoutingTable routingTable,
         DiscoveryNodes nodes,
         ClusterBlocks blocks,
-        ImmutableOpenMap<String, Custom> customs,
-        int minimumMasterNodesOnPublishingMaster,
+        final Map<String, Custom> customs,
+        int minimumClusterManagerNodesOnPublishingClusterManager,
         boolean wasReadFromDiff
     ) {
         this.version = version;
@@ -208,8 +216,8 @@ public ClusterState(
         this.routingTable = routingTable;
         this.nodes = nodes;
         this.blocks = blocks;
-        this.customs = customs;
-        this.minimumMasterNodesOnPublishingMaster = minimumMasterNodesOnPublishingMaster;
+        this.customs = Collections.unmodifiableMap(customs);
+        this.minimumClusterManagerNodesOnPublishingClusterManager = minimumClusterManagerNodesOnPublishingClusterManager;
         this.wasReadFromDiff = wasReadFromDiff;
     }
 
@@ -226,8 +234,9 @@ public long getVersion() {
     }
 
     public long getVersionOrMetadataVersion() {
-        // When following a Zen1 master, the cluster state version is not guaranteed to increase, so instead it is preferable to use the
-        // metadata version to determine the freshest node. However when following a Zen2 master the cluster state version should be used.
+        // When following a Zen1 cluster-manager, the cluster state version is not guaranteed to increase,
+        // so instead it is preferable to use the metadata version to determine the freshest node.
+        // However when following a Zen2 cluster-manager the cluster state version should be used.
         return term() == ZEN1_BWC_TERM ? metadata().version() : version();
     }
 
@@ -275,11 +284,11 @@ public ClusterBlocks getBlocks() {
         return blocks;
     }
 
-    public ImmutableOpenMap<String, Custom> customs() {
+    public Map<String, Custom> customs() {
         return this.customs;
     }
 
-    public ImmutableOpenMap<String, Custom> getCustoms() {
+    public Map<String, Custom> getCustoms() {
         return this.customs;
     }
 
@@ -365,9 +374,9 @@ public String toString() {
         }
         if (metadata.customs().isEmpty() == false) {
             sb.append("metadata customs:\n");
-            for (final ObjectObjectCursor<String, Metadata.Custom> cursor : metadata.customs()) {
-                final String type = cursor.key;
-                final Metadata.Custom custom = cursor.value;
+            for (final Map.Entry<String, Metadata.Custom> cursor : metadata.customs().entrySet()) {
+                final String type = cursor.getKey();
+                final Metadata.Custom custom = cursor.getValue();
                 sb.append(TAB).append(type).append(": ").append(custom);
             }
             sb.append("\n");
@@ -378,9 +387,9 @@ public String toString() {
         sb.append(getRoutingNodes());
         if (customs.isEmpty() == false) {
             sb.append("customs:\n");
-            for (ObjectObjectCursor<String, Custom> cursor : customs) {
-                final String type = cursor.key;
-                final Custom custom = cursor.value;
+            for (final Map.Entry<String, Custom> cursor : customs.entrySet()) {
+                final String type = cursor.getKey();
+                final Custom custom = cursor.getValue();
                 sb.append(TAB).append(type).append(": ").append(custom);
             }
         }
@@ -388,18 +397,23 @@ public String toString() {
     }
 
     /**
-     * a cluster state supersedes another state if they are from the same master and the version of this state is higher than that of the
+     * a cluster state supersedes another state if they are from the same cluster-manager and the version of this state is higher than that of the
      * other state.
      * <p>
      * In essence that means that all the changes from the other cluster state are also reflected by the current one
      */
     public boolean supersedes(ClusterState other) {
-        return this.nodes().getMasterNodeId() != null
-            && this.nodes().getMasterNodeId().equals(other.nodes().getMasterNodeId())
+        return this.nodes().getClusterManagerNodeId() != null
+            && this.nodes().getClusterManagerNodeId().equals(other.nodes().getClusterManagerNodeId())
             && this.version() > other.version();
 
     }
 
+    /**
+     * Metrics for cluster state.
+     *
+     * @opensearch.internal
+     */
     public enum Metric {
         VERSION("version"),
 
@@ -470,18 +484,18 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
 
         if (metrics.contains(Metric.MASTER_NODE)) {
-            builder.field("master_node", nodes().getMasterNodeId());
+            builder.field("master_node", nodes().getClusterManagerNodeId());
         }
 
         // Value of the field is identical with the above, and aims to replace the above field.
         if (metrics.contains(Metric.CLUSTER_MANAGER_NODE)) {
-            builder.field("cluster_manager_node", nodes().getMasterNodeId());
+            builder.field("cluster_manager_node", nodes().getClusterManagerNodeId());
         }
 
         if (metrics.contains(Metric.BLOCKS)) {
             builder.startObject("blocks");
 
-            if (!blocks().global().isEmpty()) {
+            if (blocks().global().isEmpty() == false) {
                 builder.startObject("global");
                 for (ClusterBlock block : blocks().global()) {
                     block.toXContent(builder, params);
@@ -489,11 +503,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                 builder.endObject();
             }
 
-            if (!blocks().indices().isEmpty()) {
+            if (blocks().indices().isEmpty() == false) {
                 builder.startObject("indices");
-                for (ObjectObjectCursor<String, Set<ClusterBlock>> entry : blocks().indices()) {
-                    builder.startObject(entry.key);
-                    for (ClusterBlock block : entry.value) {
+                for (final Map.Entry<String, Set<ClusterBlock>> entry : blocks().indices().entrySet()) {
+                    builder.startObject(entry.getKey());
+                    for (ClusterBlock block : entry.getValue()) {
                         block.toXContent(builder, params);
                     }
                     builder.endObject();
@@ -561,9 +575,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.endObject();
         }
         if (metrics.contains(Metric.CUSTOMS)) {
-            for (ObjectObjectCursor<String, Custom> cursor : customs) {
-                builder.startObject(cursor.key);
-                cursor.value.toXContent(builder, params);
+            for (final Map.Entry<String, Custom> cursor : customs.entrySet()) {
+                builder.startObject(cursor.getKey());
+                cursor.getValue().toXContent(builder, params);
                 builder.endObject();
             }
         }
@@ -579,18 +593,23 @@ public static Builder builder(ClusterState state) {
         return new Builder(state);
     }
 
+    /**
+     * Builder for cluster state.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final ClusterName clusterName;
         private long version = 0;
-        private String uuid = UNKNOWN_UUID;
+        private String uuid = Strings.UNKNOWN_UUID_VALUE;
         private Metadata metadata = Metadata.EMPTY_METADATA;
         private RoutingTable routingTable = RoutingTable.EMPTY_ROUTING_TABLE;
         private DiscoveryNodes nodes = DiscoveryNodes.EMPTY_NODES;
         private ClusterBlocks blocks = ClusterBlocks.EMPTY_CLUSTER_BLOCK;
-        private final ImmutableOpenMap.Builder<String, Custom> customs;
+        private final Map<String, Custom> customs;
         private boolean fromDiff;
-        private int minimumMasterNodesOnPublishingMaster = -1;
+        private int minimumClusterManagerNodesOnPublishingClusterManager = -1;
 
         public Builder(ClusterState state) {
             this.clusterName = state.clusterName;
@@ -600,13 +619,13 @@ public Builder(ClusterState state) {
             this.routingTable = state.routingTable();
             this.metadata = state.metadata();
             this.blocks = state.blocks();
-            this.customs = ImmutableOpenMap.builder(state.customs());
-            this.minimumMasterNodesOnPublishingMaster = state.minimumMasterNodesOnPublishingMaster;
+            this.customs = new HashMap<>(state.customs());
+            this.minimumClusterManagerNodesOnPublishingClusterManager = state.minimumClusterManagerNodesOnPublishingClusterManager;
             this.fromDiff = false;
         }
 
         public Builder(ClusterName clusterName) {
-            customs = ImmutableOpenMap.builder();
+            customs = new HashMap<>();
             this.clusterName = clusterName;
         }
 
@@ -662,8 +681,8 @@ public Builder stateUUID(String uuid) {
             return this;
         }
 
-        public Builder minimumMasterNodesOnPublishingMaster(int minimumMasterNodesOnPublishingMaster) {
-            this.minimumMasterNodesOnPublishingMaster = minimumMasterNodesOnPublishingMaster;
+        public Builder minimumClusterManagerNodesOnPublishingClusterManager(int minimumClusterManagerNodesOnPublishingClusterManager) {
+            this.minimumClusterManagerNodesOnPublishingClusterManager = minimumClusterManagerNodesOnPublishingClusterManager;
             return this;
         }
 
@@ -677,8 +696,9 @@ public Builder removeCustom(String type) {
             return this;
         }
 
-        public Builder customs(ImmutableOpenMap<String, Custom> customs) {
-            StreamSupport.stream(customs.spliterator(), false).forEach(cursor -> Objects.requireNonNull(cursor.value, cursor.key));
+        public Builder customs(final Map<String, Custom> customs) {
+            StreamSupport.stream(Spliterators.spliterator(customs.entrySet(), 0), false)
+                .forEach(cursor -> Objects.requireNonNull(cursor.getValue(), cursor.getKey()));
             this.customs.putAll(customs);
             return this;
         }
@@ -700,8 +720,8 @@ public ClusterState build() {
                 routingTable,
                 nodes,
                 blocks,
-                customs.build(),
-                minimumMasterNodesOnPublishingMaster,
+                customs,
+                minimumClusterManagerNodesOnPublishingClusterManager,
                 fromDiff
             );
         }
@@ -746,7 +766,7 @@ public static ClusterState readFrom(StreamInput in, DiscoveryNode localNode) thr
             Custom customIndexMetadata = in.readNamedWriteable(Custom.class);
             builder.putCustom(customIndexMetadata.getWriteableName(), customIndexMetadata);
         }
-        builder.minimumMasterNodesOnPublishingMaster = in.readVInt();
+        builder.minimumClusterManagerNodesOnPublishingClusterManager = in.readVInt();
         return builder.build();
     }
 
@@ -761,20 +781,25 @@ public void writeTo(StreamOutput out) throws IOException {
         blocks.writeTo(out);
         // filter out custom states not supported by the other node
         int numberOfCustoms = 0;
-        for (final ObjectCursor<Custom> cursor : customs.values()) {
-            if (FeatureAware.shouldSerialize(out, cursor.value)) {
+        for (final Custom custom : customs.values()) {
+            if (FeatureAware.shouldSerialize(out, custom)) {
                 numberOfCustoms++;
             }
         }
         out.writeVInt(numberOfCustoms);
-        for (final ObjectCursor<Custom> cursor : customs.values()) {
-            if (FeatureAware.shouldSerialize(out, cursor.value)) {
-                out.writeNamedWriteable(cursor.value);
+        for (final Custom custom : customs.values()) {
+            if (FeatureAware.shouldSerialize(out, custom)) {
+                out.writeNamedWriteable(custom);
             }
         }
-        out.writeVInt(minimumMasterNodesOnPublishingMaster);
+        out.writeVInt(minimumClusterManagerNodesOnPublishingClusterManager);
     }
 
+    /**
+     * The cluster state diff.
+     *
+     * @opensearch.internal
+     */
     private static class ClusterStateDiff implements Diff<ClusterState> {
 
         private final long toVersion;
@@ -793,9 +818,9 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
 
         private final Diff<ClusterBlocks> blocks;
 
-        private final Diff<ImmutableOpenMap<String, Custom>> customs;
+        private final Diff<Map<String, Custom>> customs;
 
-        private final int minimumMasterNodesOnPublishingMaster;
+        private final int minimumClusterManagerNodesOnPublishingClusterManager;
 
         ClusterStateDiff(ClusterState before, ClusterState after) {
             fromUuid = before.stateUUID;
@@ -807,7 +832,7 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
             metadata = after.metadata.diff(before.metadata);
             blocks = after.blocks.diff(before.blocks);
             customs = DiffableUtils.diff(before.customs, after.customs, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
-            minimumMasterNodesOnPublishingMaster = after.minimumMasterNodesOnPublishingMaster;
+            minimumClusterManagerNodesOnPublishingClusterManager = after.minimumClusterManagerNodesOnPublishingClusterManager;
         }
 
         ClusterStateDiff(StreamInput in, DiscoveryNode localNode) throws IOException {
@@ -819,8 +844,8 @@ private static class ClusterStateDiff implements Diff<ClusterState> {
             nodes = DiscoveryNodes.readDiffFrom(in, localNode);
             metadata = Metadata.readDiffFrom(in);
             blocks = ClusterBlocks.readDiffFrom(in);
-            customs = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
-            minimumMasterNodesOnPublishingMaster = in.readVInt();
+            customs = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
+            minimumClusterManagerNodesOnPublishingClusterManager = in.readVInt();
         }
 
         @Override
@@ -834,7 +859,7 @@ public void writeTo(StreamOutput out) throws IOException {
             metadata.writeTo(out);
             blocks.writeTo(out);
             customs.writeTo(out);
-            out.writeVInt(minimumMasterNodesOnPublishingMaster);
+            out.writeVInt(minimumClusterManagerNodesOnPublishingClusterManager);
         }
 
         @Override
@@ -854,7 +879,7 @@ public ClusterState apply(ClusterState state) {
             builder.metadata(metadata.apply(state.metadata));
             builder.blocks(blocks.apply(state.blocks));
             builder.customs(customs.apply(state.customs));
-            builder.minimumMasterNodesOnPublishingMaster(minimumMasterNodesOnPublishingMaster);
+            builder.minimumClusterManagerNodesOnPublishingClusterManager(minimumClusterManagerNodesOnPublishingClusterManager);
             builder.fromDiff(true);
             return builder.build();
         }
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateApplier.java b/server/src/main/java/org/opensearch/cluster/ClusterStateApplier.java
index 6ba7cba0b463d..140e6426bb801 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateApplier.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateApplier.java
@@ -37,6 +37,8 @@
 /**
  * A component that is in charge of applying an incoming cluster state to the node internal data structures.
  * The single apply method is called before the cluster state becomes visible via {@link ClusterService#state()}.
+ *
+ * @opensearch.internal
  */
 public interface ClusterStateApplier {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateListener.java b/server/src/main/java/org/opensearch/cluster/ClusterStateListener.java
index bbd41508fd630..01a8e51a3d13e 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateListener.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateListener.java
@@ -35,7 +35,7 @@
 /**
  * A listener to be notified when a cluster state changes.
  *
- *
+ * @opensearch.internal
  */
 public interface ClusterStateListener {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateObserver.java b/server/src/main/java/org/opensearch/cluster/ClusterStateObserver.java
index 5d55ce70aec02..7945afd120350 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateObserver.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateObserver.java
@@ -50,6 +50,8 @@
  * A utility class which simplifies interacting with the cluster state in cases where
  * one tries to take action based on the current state but may want to wait for a new state
  * and retry upon failure.
+ *
+ * @opensearch.internal
  */
 public class ClusterStateObserver {
 
@@ -187,7 +189,7 @@ public void waitForNextChange(Listener listener, Predicate<ClusterState> statePr
         // sample a new state. This state maybe *older* than the supplied state if we are called from an applier,
         // which wants to wait for something else to happen
         ClusterState newState = clusterApplierService.state();
-        if (lastObservedState.get().isOlderOrDifferentMaster(newState) && statePredicate.test(newState)) {
+        if (lastObservedState.get().isOlderOrDifferentClusterManager(newState) && statePredicate.test(newState)) {
             // good enough, let's go.
             logger.trace("observer: sampled state accepted by predicate ({})", newState);
             lastObservedState.set(new StoredState(newState));
@@ -205,6 +207,11 @@ public void waitForNextChange(Listener listener, Predicate<ClusterState> statePr
         }
     }
 
+    /**
+     * An observer of the cluster state for changes.
+     *
+     * @opensearch.internal
+     */
     class ObserverClusterStateListener implements TimeoutClusterStateListener {
 
         @Override
@@ -241,7 +248,7 @@ public void postAdded() {
                 return;
             }
             ClusterState newState = clusterApplierService.state();
-            if (lastObservedState.get().isOlderOrDifferentMaster(newState) && context.statePredicate.test(newState)) {
+            if (lastObservedState.get().isOlderOrDifferentClusterManager(newState) && context.statePredicate.test(newState)) {
                 // double check we're still listening
                 if (observingContext.compareAndSet(context, null)) {
                     logger.trace("observer: post adding listener: accepting current cluster state ({})", newState);
@@ -295,25 +302,33 @@ public String toString() {
     }
 
     /**
-     * The observer considers two cluster states to be the same if they have the same version and master node id (i.e. null or set)
+     * The observer considers two cluster states to be the same if they have the same version and cluster-manager node id (i.e. null or set)
+     *
+     * @opensearch.internal
      */
     private static class StoredState {
-        private final String masterNodeId;
+        private final String clusterManagerNodeId;
         private final long version;
 
         StoredState(ClusterState clusterState) {
-            this.masterNodeId = clusterState.nodes().getMasterNodeId();
+            this.clusterManagerNodeId = clusterState.nodes().getClusterManagerNodeId();
             this.version = clusterState.version();
         }
 
         /**
-         * returns true if stored state is older then given state or they are from a different master, meaning they can't be compared
+         * returns true if stored state is older then given state or they are from a different cluster-manager, meaning they can't be compared
          * */
-        public boolean isOlderOrDifferentMaster(ClusterState clusterState) {
-            return version < clusterState.version() || Objects.equals(masterNodeId, clusterState.nodes().getMasterNodeId()) == false;
+        public boolean isOlderOrDifferentClusterManager(ClusterState clusterState) {
+            return version < clusterState.version()
+                || Objects.equals(clusterManagerNodeId, clusterState.nodes().getClusterManagerNodeId()) == false;
         }
     }
 
+    /**
+     * Listener for the observer.
+     *
+     * @opensearch.internal
+     */
     public interface Listener {
 
         /** called when a new state is observed */
@@ -325,6 +340,11 @@ public interface Listener {
         void onTimeout(TimeValue timeout);
     }
 
+    /**
+     * Context for the observer.
+     *
+     * @opensearch.internal
+     */
     static class ObservingContext {
         public final Listener listener;
         public final Predicate<ClusterState> statePredicate;
@@ -340,6 +360,11 @@ public String toString() {
         }
     }
 
+    /**
+     * A context preserving listener.
+     *
+     * @opensearch.internal
+     */
     private static final class ContextPreservingListener implements Listener {
         private final Listener delegate;
         private final Supplier<ThreadContext.StoredContext> contextSupplier;
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskConfig.java b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskConfig.java
index ec038df7a9096..9a4b708548a7d 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskConfig.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskConfig.java
@@ -37,6 +37,8 @@
 
 /**
  * Cluster state update task configuration for timeout and priority
+ *
+ * @opensearch.internal
  */
 public interface ClusterStateTaskConfig {
     /**
@@ -83,6 +85,11 @@ static ClusterStateTaskConfig build(Priority priority, TimeValue timeout) {
         return new Basic(priority, timeout);
     }
 
+    /**
+     * Basic task config.
+     *
+     * @opensearch.internal
+     */
     class Basic implements ClusterStateTaskConfig {
         final TimeValue timeout;
         final Priority priority;
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskExecutor.java b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskExecutor.java
index 04002b31a8b3e..50beeb1f03deb 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskExecutor.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskExecutor.java
@@ -31,12 +31,18 @@
 
 package org.opensearch.cluster;
 
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.common.Nullable;
 
 import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Interface that updates the cluster state based on the task
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStateTaskExecutor<T> {
     /**
      * Update the cluster state based on the current state and the given tasks. Return the *same instance* if no state
@@ -45,12 +51,22 @@ public interface ClusterStateTaskExecutor<T> {
     ClusterTasksResult<T> execute(ClusterState currentState, List<T> tasks) throws Exception;
 
     /**
-     * indicates whether this executor should only run if the current node is master
+     * indicates whether this executor should only run if the current node is cluster-manager
      */
-    default boolean runOnlyOnMaster() {
+    default boolean runOnlyOnClusterManager() {
         return true;
     }
 
+    /**
+     * indicates whether this executor should only run if the current node is cluster-manager
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #runOnlyOnClusterManager()}
+     */
+    @Deprecated
+    default boolean runOnlyOnMaster() {
+        return runOnlyOnClusterManager();
+    }
+
     /**
      * Callback invoked after new cluster state is published. Note that
      * this method is not invoked if the cluster state was not updated.
@@ -73,9 +89,21 @@ default String describeTasks(List<T> tasks) {
         return String.join(", ", tasks.stream().map(t -> (CharSequence) t.toString()).filter(t -> t.length() > 0)::iterator);
     }
 
+    /**
+     * Throttling key associated with the task, on which cluster manager node will do aggregation count
+     * and perform throttling based on configured threshold in cluster setting.
+     */
+    default ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+        // Default task is not registered with clusterService.registerClusterMangerTask,
+        // User can't configure throttling limit on it and will be bypassed while throttling on cluster manager
+        return ClusterManagerTaskThrottler.DEFAULT_THROTTLING_KEY;
+    }
+
     /**
      * Represents the result of a batched execution of cluster state update tasks
      * @param <T> the type of the cluster state update task
+     *
+     * @opensearch.internal
      */
     class ClusterTasksResult<T> {
         @Nullable
@@ -96,6 +124,11 @@ public static <T> Builder<T> builder() {
             return new Builder<>();
         }
 
+        /**
+         * Builder for cluster state task.
+         *
+         * @opensearch.internal
+         */
         public static class Builder<T> {
             private final Map<T, TaskResult> executionResults = new IdentityHashMap<>();
 
@@ -137,6 +170,11 @@ ClusterTasksResult<T> build(ClusterTasksResult<T> result, ClusterState previousS
         }
     }
 
+    /**
+     * The task result.
+     *
+     * @opensearch.internal
+     */
     final class TaskResult {
         private final Exception failure;
 
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskListener.java b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskListener.java
index 718df33f8a2d2..d6c4abfad7b8d 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateTaskListener.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateTaskListener.java
@@ -31,10 +31,15 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
 
 import java.util.List;
 
+/**
+ * Interface to implement a cluster state change listener
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStateTaskListener {
 
     /**
@@ -43,11 +48,22 @@ public interface ClusterStateTaskListener {
     void onFailure(String source, Exception e);
 
     /**
-     * called when the task was rejected because the local node is no longer master.
-     * Used only for tasks submitted to {@link MasterService}.
+     * called when the task was rejected because the local node is no longer cluster-manager.
+     * Used only for tasks submitted to {@link ClusterManagerService}.
+     */
+    default void onNoLongerClusterManager(String source) {
+        onFailure(source, new NotClusterManagerException("no longer cluster-manager. source: [" + source + "]"));
+    }
+
+    /**
+     * called when the task was rejected because the local node is no longer cluster-manager.
+     * Used only for tasks submitted to {@link ClusterManagerService}.
+     *
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #onNoLongerClusterManager(String)}
      */
+    @Deprecated
     default void onNoLongerMaster(String source) {
-        onFailure(source, new NotMasterException("no longer master. source: [" + source + "]"));
+        onNoLongerClusterManager(source);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/ClusterStateUpdateTask.java b/server/src/main/java/org/opensearch/cluster/ClusterStateUpdateTask.java
index 72d72158a5f0b..9225914a931b2 100644
--- a/server/src/main/java/org/opensearch/cluster/ClusterStateUpdateTask.java
+++ b/server/src/main/java/org/opensearch/cluster/ClusterStateUpdateTask.java
@@ -40,6 +40,8 @@
 
 /**
  * A task that can update the cluster state.
+ *
+ * @opensearch.internal
  */
 public abstract class ClusterStateUpdateTask
     implements
@@ -101,11 +103,11 @@ public Priority priority() {
     }
 
     /**
-     * Marked as final as cluster state update tasks should only run on master.
+     * Marked as final as cluster state update tasks should only run on cluster-manager.
      * For local requests, use {@link LocalClusterUpdateTask} instead.
      */
     @Override
-    public final boolean runOnlyOnMaster() {
+    public final boolean runOnlyOnClusterManager() {
         return true;
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/Diff.java b/server/src/main/java/org/opensearch/cluster/Diff.java
index 165fb750f3f53..c0e8e7038d9b4 100644
--- a/server/src/main/java/org/opensearch/cluster/Diff.java
+++ b/server/src/main/java/org/opensearch/cluster/Diff.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 
 /**
  * Represents difference between states of cluster state parts
+ *
+ * @opensearch.internal
  */
 public interface Diff<T> extends Writeable {
 
diff --git a/server/src/main/java/org/opensearch/cluster/Diffable.java b/server/src/main/java/org/opensearch/cluster/Diffable.java
index 3dcac5459d27d..a3fedf4903089 100644
--- a/server/src/main/java/org/opensearch/cluster/Diffable.java
+++ b/server/src/main/java/org/opensearch/cluster/Diffable.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 
 /**
  * Cluster state part, changes in which can be serialized
+ *
+ * @opensearch.internal
  */
 public interface Diffable<T> extends Writeable {
 
diff --git a/server/src/main/java/org/opensearch/cluster/DiffableUtils.java b/server/src/main/java/org/opensearch/cluster/DiffableUtils.java
index 76da490eca1f3..dd2232968114e 100644
--- a/server/src/main/java/org/opensearch/cluster/DiffableUtils.java
+++ b/server/src/main/java/org/opensearch/cluster/DiffableUtils.java
@@ -32,16 +32,10 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.IntCursor;
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.Version;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -53,6 +47,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Utility class for a diffable
+ *
+ * @opensearch.internal
+ */
 public final class DiffableUtils {
     private DiffableUtils() {}
 
@@ -77,56 +76,6 @@ public static KeySerializer<Integer> getVIntKeySerializer() {
         return VIntKeySerializer.INSTANCE;
     }
 
-    /**
-     * Calculates diff between two ImmutableOpenMaps of Diffable objects
-     */
-    public static <K, T extends Diffable<T>> MapDiff<K, T, ImmutableOpenMap<K, T>> diff(
-        ImmutableOpenMap<K, T> before,
-        ImmutableOpenMap<K, T> after,
-        KeySerializer<K> keySerializer
-    ) {
-        assert after != null && before != null;
-        return new ImmutableOpenMapDiff<>(before, after, keySerializer, DiffableValueSerializer.getWriteOnlyInstance());
-    }
-
-    /**
-     * Calculates diff between two ImmutableOpenMaps of non-diffable objects
-     */
-    public static <K, T> MapDiff<K, T, ImmutableOpenMap<K, T>> diff(
-        ImmutableOpenMap<K, T> before,
-        ImmutableOpenMap<K, T> after,
-        KeySerializer<K> keySerializer,
-        ValueSerializer<K, T> valueSerializer
-    ) {
-        assert after != null && before != null;
-        return new ImmutableOpenMapDiff<>(before, after, keySerializer, valueSerializer);
-    }
-
-    /**
-     * Calculates diff between two ImmutableOpenIntMaps of Diffable objects
-     */
-    public static <T extends Diffable<T>> MapDiff<Integer, T, ImmutableOpenIntMap<T>> diff(
-        ImmutableOpenIntMap<T> before,
-        ImmutableOpenIntMap<T> after,
-        KeySerializer<Integer> keySerializer
-    ) {
-        assert after != null && before != null;
-        return new ImmutableOpenIntMapDiff<>(before, after, keySerializer, DiffableValueSerializer.getWriteOnlyInstance());
-    }
-
-    /**
-     * Calculates diff between two ImmutableOpenIntMaps of non-diffable objects
-     */
-    public static <T> MapDiff<Integer, T, ImmutableOpenIntMap<T>> diff(
-        ImmutableOpenIntMap<T> before,
-        ImmutableOpenIntMap<T> after,
-        KeySerializer<Integer> keySerializer,
-        ValueSerializer<Integer, T> valueSerializer
-    ) {
-        assert after != null && before != null;
-        return new ImmutableOpenIntMapDiff<>(before, after, keySerializer, valueSerializer);
-    }
-
     /**
      * Calculates diff between two Maps of Diffable objects.
      */
@@ -152,28 +101,6 @@ public static <K, T> MapDiff<K, T, Map<K, T>> diff(
         return new JdkMapDiff<>(before, after, keySerializer, valueSerializer);
     }
 
-    /**
-     * Loads an object that represents difference between two ImmutableOpenMaps
-     */
-    public static <K, T> MapDiff<K, T, ImmutableOpenMap<K, T>> readImmutableOpenMapDiff(
-        StreamInput in,
-        KeySerializer<K> keySerializer,
-        ValueSerializer<K, T> valueSerializer
-    ) throws IOException {
-        return new ImmutableOpenMapDiff<>(in, keySerializer, valueSerializer);
-    }
-
-    /**
-     * Loads an object that represents difference between two ImmutableOpenMaps
-     */
-    public static <T> MapDiff<Integer, T, ImmutableOpenIntMap<T>> readImmutableOpenIntMapDiff(
-        StreamInput in,
-        KeySerializer<Integer> keySerializer,
-        ValueSerializer<Integer, T> valueSerializer
-    ) throws IOException {
-        return new ImmutableOpenIntMapDiff<>(in, keySerializer, valueSerializer);
-    }
-
     /**
      * Loads an object that represents difference between two Maps of Diffable objects
      */
@@ -185,29 +112,6 @@ public static <K, T> MapDiff<K, T, Map<K, T>> readJdkMapDiff(
         return new JdkMapDiff<>(in, keySerializer, valueSerializer);
     }
 
-    /**
-     * Loads an object that represents difference between two ImmutableOpenMaps of Diffable objects using Diffable proto object
-     */
-    public static <K, T extends Diffable<T>> MapDiff<K, T, ImmutableOpenMap<K, T>> readImmutableOpenMapDiff(
-        StreamInput in,
-        KeySerializer<K> keySerializer,
-        DiffableValueReader<K, T> diffableValueReader
-    ) throws IOException {
-        return new ImmutableOpenMapDiff<>(in, keySerializer, diffableValueReader);
-    }
-
-    /**
-     * Loads an object that represents difference between two ImmutableOpenIntMaps of Diffable objects using Diffable proto object
-     */
-    public static <T extends Diffable<T>> MapDiff<Integer, T, ImmutableOpenIntMap<T>> readImmutableOpenIntMapDiff(
-        StreamInput in,
-        KeySerializer<Integer> keySerializer,
-        Reader<T> reader,
-        Reader<Diff<T>> diffReader
-    ) throws IOException {
-        return new ImmutableOpenIntMapDiff<>(in, keySerializer, new DiffableValueReader<>(reader, diffReader));
-    }
-
     /**
      * Loads an object that represents difference between two Maps of Diffable objects using Diffable proto object
      */
@@ -224,6 +128,8 @@ public static <K, T extends Diffable<T>> MapDiff<K, T, Map<K, T>> readJdkMapDiff
      * Represents differences between two Maps of (possibly diffable) objects.
      *
      * @param <T> the diffable object
+     *
+     * @opensearch.internal
      */
     private static class JdkMapDiff<K, T> extends MapDiff<K, T, Map<K, T>> {
 
@@ -274,153 +180,6 @@ public Map<K, T> apply(Map<K, T> map) {
         }
     }
 
-    /**
-     * Represents differences between two ImmutableOpenMap of (possibly diffable) objects
-     *
-     * @param <T> the object type
-     */
-    public static class ImmutableOpenMapDiff<K, T> extends MapDiff<K, T, ImmutableOpenMap<K, T>> {
-
-        protected ImmutableOpenMapDiff(StreamInput in, KeySerializer<K> keySerializer, ValueSerializer<K, T> valueSerializer)
-            throws IOException {
-            super(in, keySerializer, valueSerializer);
-        }
-
-        private ImmutableOpenMapDiff(
-            KeySerializer<K> keySerializer,
-            ValueSerializer<K, T> valueSerializer,
-            List<K> deletes,
-            Map<K, Diff<T>> diffs,
-            Map<K, T> upserts
-        ) {
-            super(keySerializer, valueSerializer, deletes, diffs, upserts);
-        }
-
-        public ImmutableOpenMapDiff(
-            ImmutableOpenMap<K, T> before,
-            ImmutableOpenMap<K, T> after,
-            KeySerializer<K> keySerializer,
-            ValueSerializer<K, T> valueSerializer
-        ) {
-            super(keySerializer, valueSerializer);
-            assert after != null && before != null;
-
-            for (ObjectCursor<K> key : before.keys()) {
-                if (!after.containsKey(key.value)) {
-                    deletes.add(key.value);
-                }
-            }
-
-            for (ObjectObjectCursor<K, T> partIter : after) {
-                T beforePart = before.get(partIter.key);
-                if (beforePart == null) {
-                    upserts.put(partIter.key, partIter.value);
-                } else if (partIter.value.equals(beforePart) == false) {
-                    if (valueSerializer.supportsDiffableValues()) {
-                        diffs.put(partIter.key, valueSerializer.diff(partIter.value, beforePart));
-                    } else {
-                        upserts.put(partIter.key, partIter.value);
-                    }
-                }
-            }
-        }
-
-        /**
-         * Returns a new diff map with the given key removed, does not modify the invoking instance.
-         * If the key does not exist in the diff map, the same instance is returned.
-         */
-        public ImmutableOpenMapDiff<K, T> withKeyRemoved(K key) {
-            if (this.diffs.containsKey(key) == false && this.upserts.containsKey(key) == false) {
-                return this;
-            }
-            Map<K, Diff<T>> newDiffs = new HashMap<>(this.diffs);
-            newDiffs.remove(key);
-            Map<K, T> newUpserts = new HashMap<>(this.upserts);
-            newUpserts.remove(key);
-            return new ImmutableOpenMapDiff<>(this.keySerializer, this.valueSerializer, this.deletes, newDiffs, newUpserts);
-        }
-
-        @Override
-        public ImmutableOpenMap<K, T> apply(ImmutableOpenMap<K, T> map) {
-            ImmutableOpenMap.Builder<K, T> builder = ImmutableOpenMap.builder();
-            builder.putAll(map);
-
-            for (K part : deletes) {
-                builder.remove(part);
-            }
-
-            for (Map.Entry<K, Diff<T>> diff : diffs.entrySet()) {
-                builder.put(diff.getKey(), diff.getValue().apply(builder.get(diff.getKey())));
-            }
-
-            for (Map.Entry<K, T> upsert : upserts.entrySet()) {
-                builder.put(upsert.getKey(), upsert.getValue());
-            }
-            return builder.build();
-        }
-    }
-
-    /**
-     * Represents differences between two ImmutableOpenIntMap of (possibly diffable) objects
-     *
-     * @param <T> the object type
-     */
-    private static class ImmutableOpenIntMapDiff<T> extends MapDiff<Integer, T, ImmutableOpenIntMap<T>> {
-
-        protected ImmutableOpenIntMapDiff(StreamInput in, KeySerializer<Integer> keySerializer, ValueSerializer<Integer, T> valueSerializer)
-            throws IOException {
-            super(in, keySerializer, valueSerializer);
-        }
-
-        ImmutableOpenIntMapDiff(
-            ImmutableOpenIntMap<T> before,
-            ImmutableOpenIntMap<T> after,
-            KeySerializer<Integer> keySerializer,
-            ValueSerializer<Integer, T> valueSerializer
-        ) {
-            super(keySerializer, valueSerializer);
-            assert after != null && before != null;
-
-            for (IntCursor key : before.keys()) {
-                if (!after.containsKey(key.value)) {
-                    deletes.add(key.value);
-                }
-            }
-
-            for (IntObjectCursor<T> partIter : after) {
-                T beforePart = before.get(partIter.key);
-                if (beforePart == null) {
-                    upserts.put(partIter.key, partIter.value);
-                } else if (partIter.value.equals(beforePart) == false) {
-                    if (valueSerializer.supportsDiffableValues()) {
-                        diffs.put(partIter.key, valueSerializer.diff(partIter.value, beforePart));
-                    } else {
-                        upserts.put(partIter.key, partIter.value);
-                    }
-                }
-            }
-        }
-
-        @Override
-        public ImmutableOpenIntMap<T> apply(ImmutableOpenIntMap<T> map) {
-            ImmutableOpenIntMap.Builder<T> builder = ImmutableOpenIntMap.builder();
-            builder.putAll(map);
-
-            for (Integer part : deletes) {
-                builder.remove(part);
-            }
-
-            for (Map.Entry<Integer, Diff<T>> diff : diffs.entrySet()) {
-                builder.put(diff.getKey(), diff.getValue().apply(builder.get(diff.getKey())));
-            }
-
-            for (Map.Entry<Integer, T> upsert : upserts.entrySet()) {
-                builder.put(upsert.getKey(), upsert.getValue());
-            }
-            return builder.build();
-        }
-    }
-
     /**
      * Represents differences between two maps of objects and is used as base class for different map implementations.
      *
@@ -429,6 +188,8 @@ public ImmutableOpenIntMap<T> apply(ImmutableOpenIntMap<T> map) {
      * @param <K> the type of map keys
      * @param <T> the type of map values
      * @param <M> the map implementation type
+     *
+     * @opensearch.internal
      */
     public abstract static class MapDiff<K, T, M> implements Diff<M> {
 
@@ -548,6 +309,8 @@ public void writeTo(StreamOutput out) throws IOException {
     /**
      * Provides read and write operations to serialize keys of map
      * @param <K> type of key
+     *
+     * @opensearch.internal
      */
     public interface KeySerializer<K> {
         void writeKey(K key, StreamOutput out) throws IOException;
@@ -557,6 +320,8 @@ public interface KeySerializer<K> {
 
     /**
      * Serializes String keys of a map
+     *
+     * @opensearch.internal
      */
     private static final class StringKeySerializer implements KeySerializer<String> {
         private static final StringKeySerializer INSTANCE = new StringKeySerializer();
@@ -574,6 +339,8 @@ public String readKey(StreamInput in) throws IOException {
 
     /**
      * Serializes Integer keys of a map as an Int
+     *
+     * @opensearch.internal
      */
     private static final class IntKeySerializer implements KeySerializer<Integer> {
         public static final IntKeySerializer INSTANCE = new IntKeySerializer();
@@ -591,6 +358,8 @@ public Integer readKey(StreamInput in) throws IOException {
 
     /**
      * Serializes Integer keys of a map as a VInt. Requires keys to be positive.
+     *
+     * @opensearch.internal
      */
     private static final class VIntKeySerializer implements KeySerializer<Integer> {
         public static final IntKeySerializer INSTANCE = new IntKeySerializer();
@@ -620,6 +389,8 @@ public Integer readKey(StreamInput in) throws IOException {
      *
      * @param <K> key type of map
      * @param <V> value type of map
+     *
+     * @opensearch.internal
      */
     public interface ValueSerializer<K, V> {
 
@@ -674,6 +445,8 @@ default boolean supportsVersion(V value, Version version) {
      *
      * @param <K> type of map keys
      * @param <V> type of map values
+     *
+     * @opensearch.internal
      */
     public abstract static class DiffableValueSerializer<K, V extends Diffable<V>> implements ValueSerializer<K, V> {
         private static final DiffableValueSerializer WRITE_ONLY_INSTANCE = new DiffableValueSerializer() {
@@ -717,6 +490,8 @@ public void writeDiff(Diff<V> value, StreamOutput out) throws IOException {
      *
      * @param <K> type of map keys
      * @param <V> type of map values
+     *
+     * @opensearch.internal
      */
     public abstract static class NonDiffableValueSerializer<K, V> implements ValueSerializer<K, V> {
         @Override
@@ -744,6 +519,8 @@ public Diff<V> readDiff(StreamInput in, K key) throws IOException {
      * Implementation of the ValueSerializer that wraps value and diff readers.
      *
      * Note: this implementation is ignoring the key.
+     *
+     * @opensearch.internal
      */
     public static class DiffableValueReader<K, V extends Diffable<V>> extends DiffableValueSerializer<K, V> {
         private final Reader<V> reader;
@@ -769,6 +546,8 @@ public Diff<V> readDiff(StreamInput in, K key) throws IOException {
      * Implementation of ValueSerializer that serializes immutable sets
      *
      * @param <K> type of map key
+     *
+     * @opensearch.internal
      */
     public static class StringSetValueSerializer<K> extends NonDiffableValueSerializer<K, Set<String>> {
         private static final StringSetValueSerializer INSTANCE = new StringSetValueSerializer();
diff --git a/server/src/main/java/org/opensearch/cluster/DiskUsage.java b/server/src/main/java/org/opensearch/cluster/DiskUsage.java
index e7f04ffb749b9..c472522baee51 100644
--- a/server/src/main/java/org/opensearch/cluster/DiskUsage.java
+++ b/server/src/main/java/org/opensearch/cluster/DiskUsage.java
@@ -32,19 +32,21 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Encapsulation class used to represent the amount of disk used on a node.
+ *
+ * @opensearch.internal
  */
 public class DiskUsage implements ToXContentFragment, Writeable {
     final String nodeId;
diff --git a/server/src/main/java/org/opensearch/cluster/EmptyClusterInfoService.java b/server/src/main/java/org/opensearch/cluster/EmptyClusterInfoService.java
index cf2ce4c3f9ae0..27d1c706eb012 100644
--- a/server/src/main/java/org/opensearch/cluster/EmptyClusterInfoService.java
+++ b/server/src/main/java/org/opensearch/cluster/EmptyClusterInfoService.java
@@ -36,6 +36,8 @@
 
 /**
  * {@link ClusterInfoService} that provides empty maps for disk usage and shard sizes
+ *
+ * @opensearch.internal
  */
 public class EmptyClusterInfoService implements ClusterInfoService {
     public static final EmptyClusterInfoService INSTANCE = new EmptyClusterInfoService();
diff --git a/server/src/main/java/org/opensearch/cluster/IncompatibleClusterStateVersionException.java b/server/src/main/java/org/opensearch/cluster/IncompatibleClusterStateVersionException.java
index 5ce71c651ae61..671748e52c544 100644
--- a/server/src/main/java/org/opensearch/cluster/IncompatibleClusterStateVersionException.java
+++ b/server/src/main/java/org/opensearch/cluster/IncompatibleClusterStateVersionException.java
@@ -33,12 +33,14 @@
 package org.opensearch.cluster;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown by {@link Diff#apply} method
+ *
+ * @opensearch.internal
  */
 public class IncompatibleClusterStateVersionException extends OpenSearchException {
     public IncompatibleClusterStateVersionException(String msg) {
diff --git a/server/src/main/java/org/opensearch/cluster/InternalClusterInfoService.java b/server/src/main/java/org/opensearch/cluster/InternalClusterInfoService.java
index 05d91fdfd9ebb..35490d2f37a49 100644
--- a/server/src/main/java/org/opensearch/cluster/InternalClusterInfoService.java
+++ b/server/src/main/java/org/opensearch/cluster/InternalClusterInfoService.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
@@ -51,19 +50,21 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.store.StoreStats;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ReceiveTimeoutTransportException;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -72,17 +73,20 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 /**
  * InternalClusterInfoService provides the ClusterInfoService interface,
  * routinely updated on a timer. The timer can be dynamically changed by
  * setting the <code>cluster.info.update.interval</code> setting (defaulting
- * to 30 seconds). The InternalClusterInfoService only runs on the master node.
+ * to 30 seconds). The InternalClusterInfoService only runs on the cluster-manager node.
  * Listens for changes in the number of data nodes and immediately submits a
  * ClusterInfoUpdateJob if a node has been added.
  *
  * Every time the timer runs, gathers information about the disk usage and
  * shard sizes across the cluster.
+ *
+ * @opensearch.internal
  */
 public class InternalClusterInfoService implements ClusterInfoService, ClusterStateListener {
 
@@ -106,10 +110,11 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
 
     private volatile TimeValue updateFrequency;
 
-    private volatile ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsages;
-    private volatile ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsages;
+    private volatile Map<String, DiskUsage> leastAvailableSpaceUsages;
+    private volatile Map<String, DiskUsage> mostAvailableSpaceUsages;
+    private volatile Map<String, FileCacheStats> nodeFileCacheStats;
     private volatile IndicesStatsSummary indicesStatsSummary;
-    // null if this node is not currently the master
+    // null if this node is not currently the cluster-manager
     private final AtomicReference<RefreshAndRescheduleRunnable> refreshAndRescheduleRunnable = new AtomicReference<>();
     private volatile boolean enabled;
     private volatile TimeValue fetchTimeout;
@@ -118,8 +123,9 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
     private final List<Consumer<ClusterInfo>> listeners = new CopyOnWriteArrayList<>();
 
     public InternalClusterInfoService(Settings settings, ClusterService clusterService, ThreadPool threadPool, Client client) {
-        this.leastAvailableSpaceUsages = ImmutableOpenMap.of();
-        this.mostAvailableSpaceUsages = ImmutableOpenMap.of();
+        this.leastAvailableSpaceUsages = Map.of();
+        this.mostAvailableSpaceUsages = Map.of();
+        this.nodeFileCacheStats = Map.of();
         this.indicesStatsSummary = IndicesStatsSummary.EMPTY;
         this.threadPool = threadPool;
         this.client = client;
@@ -149,14 +155,14 @@ void setUpdateFrequency(TimeValue updateFrequency) {
 
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
-        if (event.localNodeMaster() && refreshAndRescheduleRunnable.get() == null) {
-            logger.trace("elected as master, scheduling cluster info update tasks");
-            executeRefresh(event.state(), "became master");
+        if (event.localNodeClusterManager() && refreshAndRescheduleRunnable.get() == null) {
+            logger.trace("elected as cluster-manager, scheduling cluster info update tasks");
+            executeRefresh(event.state(), "became cluster-manager");
 
             final RefreshAndRescheduleRunnable newRunnable = new RefreshAndRescheduleRunnable();
             refreshAndRescheduleRunnable.set(newRunnable);
             threadPool.scheduleUnlessShuttingDown(updateFrequency, REFRESH_EXECUTOR, newRunnable);
-        } else if (event.localNodeMaster() == false) {
+        } else if (event.localNodeClusterManager() == false) {
             refreshAndRescheduleRunnable.set(null);
             return;
         }
@@ -178,14 +184,14 @@ public void clusterChanged(ClusterChangedEvent event) {
             if (removedNode.isDataNode()) {
                 logger.trace("Removing node from cluster info: {}", removedNode.getId());
                 if (leastAvailableSpaceUsages.containsKey(removedNode.getId())) {
-                    ImmutableOpenMap.Builder<String, DiskUsage> newMaxUsages = ImmutableOpenMap.builder(leastAvailableSpaceUsages);
+                    Map<String, DiskUsage> newMaxUsages = new HashMap<>(leastAvailableSpaceUsages);
                     newMaxUsages.remove(removedNode.getId());
-                    leastAvailableSpaceUsages = newMaxUsages.build();
+                    leastAvailableSpaceUsages = Collections.unmodifiableMap(newMaxUsages);
                 }
                 if (mostAvailableSpaceUsages.containsKey(removedNode.getId())) {
-                    ImmutableOpenMap.Builder<String, DiskUsage> newMinUsages = ImmutableOpenMap.builder(mostAvailableSpaceUsages);
+                    Map<String, DiskUsage> newMinUsages = new HashMap<>(mostAvailableSpaceUsages);
                     newMinUsages.remove(removedNode.getId());
-                    mostAvailableSpaceUsages = newMinUsages.build();
+                    mostAvailableSpaceUsages = Collections.unmodifiableMap(newMinUsages);
                 }
             }
         }
@@ -206,7 +212,8 @@ public ClusterInfo getClusterInfo() {
             mostAvailableSpaceUsages,
             indicesStatsSummary.shardSizes,
             indicesStatsSummary.shardRoutingToDataPath,
-            indicesStatsSummary.reservedSpace
+            indicesStatsSummary.reservedSpace,
+            nodeFileCacheStats
         );
     }
 
@@ -219,6 +226,7 @@ protected CountDownLatch updateNodeStats(final ActionListener<NodesStatsResponse
         final NodesStatsRequest nodesStatsRequest = new NodesStatsRequest("data:true");
         nodesStatsRequest.clear();
         nodesStatsRequest.addMetric(NodesStatsRequest.Metric.FS.metricName());
+        nodesStatsRequest.addMetric(NodesStatsRequest.Metric.FILE_CACHE_STATS.metricName());
         nodesStatsRequest.timeout(fetchTimeout);
         client.admin().cluster().nodesStats(nodesStatsRequest, new LatchedActionListener<>(listener, latch));
         return latch;
@@ -252,16 +260,23 @@ public final ClusterInfo refresh() {
         final CountDownLatch nodeLatch = updateNodeStats(new ActionListener<NodesStatsResponse>() {
             @Override
             public void onResponse(NodesStatsResponse nodesStatsResponse) {
-                ImmutableOpenMap.Builder<String, DiskUsage> leastAvailableUsagesBuilder = ImmutableOpenMap.builder();
-                ImmutableOpenMap.Builder<String, DiskUsage> mostAvailableUsagesBuilder = ImmutableOpenMap.builder();
+                final Map<String, DiskUsage> leastAvailableUsagesBuilder = new HashMap<>();
+                final Map<String, DiskUsage> mostAvailableUsagesBuilder = new HashMap<>();
                 fillDiskUsagePerNode(
                     logger,
                     adjustNodesStats(nodesStatsResponse.getNodes()),
                     leastAvailableUsagesBuilder,
                     mostAvailableUsagesBuilder
                 );
-                leastAvailableSpaceUsages = leastAvailableUsagesBuilder.build();
-                mostAvailableSpaceUsages = mostAvailableUsagesBuilder.build();
+                leastAvailableSpaceUsages = Collections.unmodifiableMap(leastAvailableUsagesBuilder);
+                mostAvailableSpaceUsages = Collections.unmodifiableMap(mostAvailableUsagesBuilder);
+
+                nodeFileCacheStats = Collections.unmodifiableMap(
+                    nodesStatsResponse.getNodes()
+                        .stream()
+                        .filter(nodeStats -> nodeStats.getNode().isSearchNode())
+                        .collect(Collectors.toMap(nodeStats -> nodeStats.getNode().getId(), NodeStats::getFileCacheStats))
+                );
             }
 
             @Override
@@ -277,29 +292,25 @@ public void onFailure(Exception e) {
                         logger.warn("Failed to execute NodeStatsAction for ClusterInfoUpdateJob", e);
                     }
                     // we empty the usages list, to be safe - we don't know what's going on.
-                    leastAvailableSpaceUsages = ImmutableOpenMap.of();
-                    mostAvailableSpaceUsages = ImmutableOpenMap.of();
+                    leastAvailableSpaceUsages = Map.of();
+                    mostAvailableSpaceUsages = Map.of();
                 }
             }
         });
 
-        final CountDownLatch indicesLatch = updateIndicesStats(new ActionListener<IndicesStatsResponse>() {
+        final CountDownLatch indicesLatch = updateIndicesStats(new ActionListener<>() {
             @Override
             public void onResponse(IndicesStatsResponse indicesStatsResponse) {
                 final ShardStats[] stats = indicesStatsResponse.getShards();
-                final ImmutableOpenMap.Builder<String, Long> shardSizeByIdentifierBuilder = ImmutableOpenMap.builder();
-                final ImmutableOpenMap.Builder<ShardRouting, String> dataPathByShardRoutingBuilder = ImmutableOpenMap.builder();
+                final Map<String, Long> shardSizeByIdentifierBuilder = new HashMap<>();
+                final Map<ShardRouting, String> dataPathByShardRoutingBuilder = new HashMap<>();
                 final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace.Builder> reservedSpaceBuilders = new HashMap<>();
                 buildShardLevelInfo(logger, stats, shardSizeByIdentifierBuilder, dataPathByShardRoutingBuilder, reservedSpaceBuilders);
 
-                final ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> rsrvdSpace = ImmutableOpenMap.builder();
+                final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> rsrvdSpace = new HashMap<>();
                 reservedSpaceBuilders.forEach((nodeAndPath, builder) -> rsrvdSpace.put(nodeAndPath, builder.build()));
 
-                indicesStatsSummary = new IndicesStatsSummary(
-                    shardSizeByIdentifierBuilder.build(),
-                    dataPathByShardRoutingBuilder.build(),
-                    rsrvdSpace.build()
-                );
+                indicesStatsSummary = new IndicesStatsSummary(shardSizeByIdentifierBuilder, dataPathByShardRoutingBuilder, rsrvdSpace);
             }
 
             @Override
@@ -358,9 +369,9 @@ public void addListener(Consumer<ClusterInfo> clusterInfoConsumer) {
     static void buildShardLevelInfo(
         Logger logger,
         ShardStats[] stats,
-        ImmutableOpenMap.Builder<String, Long> shardSizes,
-        ImmutableOpenMap.Builder<ShardRouting, String> newShardRoutingToDataPath,
-        Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace.Builder> reservedSpaceByShard
+        final Map<String, Long> shardSizes,
+        final Map<ShardRouting, String> newShardRoutingToDataPath,
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace.Builder> reservedSpaceByShard
     ) {
         for (ShardStats s : stats) {
             final ShardRouting shardRouting = s.getShardRouting();
@@ -390,8 +401,8 @@ static void buildShardLevelInfo(
     static void fillDiskUsagePerNode(
         Logger logger,
         List<NodeStats> nodeStatsArray,
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvailableUsages,
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvailableUsages
+        final Map<String, DiskUsage> newLeastAvailableUsages,
+        final Map<String, DiskUsage> newMostAvailableUsages
     ) {
         for (NodeStats nodeStats : nodeStatsArray) {
             if (nodeStats.getFs() == null) {
@@ -467,21 +478,22 @@ static void fillDiskUsagePerNode(
         }
     }
 
+    /**
+     * Indices statistics summary.
+     *
+     * @opensearch.internal
+     */
     private static class IndicesStatsSummary {
-        static final IndicesStatsSummary EMPTY = new IndicesStatsSummary(
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of()
-        );
+        static final IndicesStatsSummary EMPTY = new IndicesStatsSummary(Map.of(), Map.of(), Map.of());
 
-        final ImmutableOpenMap<String, Long> shardSizes;
-        final ImmutableOpenMap<ShardRouting, String> shardRoutingToDataPath;
-        final ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace;
+        final Map<String, Long> shardSizes;
+        final Map<ShardRouting, String> shardRoutingToDataPath;
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace;
 
         IndicesStatsSummary(
-            ImmutableOpenMap<String, Long> shardSizes,
-            ImmutableOpenMap<ShardRouting, String> shardRoutingToDataPath,
-            ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
+            final Map<String, Long> shardSizes,
+            final Map<ShardRouting, String> shardRoutingToDataPath,
+            final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
         ) {
             this.shardSizes = shardSizes;
             this.shardRoutingToDataPath = shardRoutingToDataPath;
@@ -491,6 +503,8 @@ private static class IndicesStatsSummary {
 
     /**
      * Runs {@link InternalClusterInfoService#refresh()}, logging failures/rejections appropriately.
+     *
+     * @opensearch.internal
      */
     private class RefreshRunnable extends AbstractRunnable {
         private final String reason;
@@ -524,6 +538,8 @@ public void onRejection(Exception e) {
 
     /**
      * Runs {@link InternalClusterInfoService#refresh()}, logging failures/rejections appropriately, and reschedules itself on completion.
+     *
+     * @opensearch.internal
      */
     private class RefreshAndRescheduleRunnable extends RefreshRunnable {
         RefreshAndRescheduleRunnable() {
@@ -535,7 +551,7 @@ protected void doRun() {
             if (this == refreshAndRescheduleRunnable.get()) {
                 super.doRun();
             } else {
-                logger.trace("master changed, scheduled refresh job is stale");
+                logger.trace("cluster-manager changed, scheduled refresh job is stale");
             }
         }
 
diff --git a/server/src/main/java/org/opensearch/cluster/LocalClusterUpdateTask.java b/server/src/main/java/org/opensearch/cluster/LocalClusterUpdateTask.java
index 06ed0c0580e2f..d730be1f2afb6 100644
--- a/server/src/main/java/org/opensearch/cluster/LocalClusterUpdateTask.java
+++ b/server/src/main/java/org/opensearch/cluster/LocalClusterUpdateTask.java
@@ -38,7 +38,9 @@
 import java.util.List;
 
 /**
- * Used to apply state updates on nodes that are not necessarily master
+ * Used to apply state updates on nodes that are not necessarily cluster-manager
+ *
+ * @opensearch.internal
  */
 public abstract class LocalClusterUpdateTask
     implements
@@ -89,7 +91,7 @@ public Priority priority() {
     }
 
     @Override
-    public final boolean runOnlyOnMaster() {
+    public final boolean runOnlyOnClusterManager() {
         return false;
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/LocalNodeClusterManagerListener.java b/server/src/main/java/org/opensearch/cluster/LocalNodeClusterManagerListener.java
new file mode 100644
index 0000000000000..c07dcc5daaee6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/LocalNodeClusterManagerListener.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+/**
+ * Enables listening to cluster-manager changes events of the local node (when the local node becomes the cluster-manager, and when the local
+ * node cease being a cluster-manager).
+ *
+ * @opensearch.internal
+ */
+public interface LocalNodeClusterManagerListener extends ClusterStateListener {
+
+    /**
+     * Called when local node is elected to be the cluster-manager
+     */
+    void onClusterManager();
+
+    /**
+     * Called when the local node used to be the cluster-manager, a new cluster-manager was elected and it's no longer the local node.
+     */
+    void offClusterManager();
+
+    @Override
+    default void clusterChanged(ClusterChangedEvent event) {
+        final boolean wasClusterManager = event.previousState().nodes().isLocalNodeElectedClusterManager();
+        final boolean isClusterManager = event.localNodeClusterManager();
+        if (wasClusterManager == false && isClusterManager) {
+            onClusterManager();
+        } else if (wasClusterManager && isClusterManager == false) {
+            offClusterManager();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/LocalNodeMasterListener.java b/server/src/main/java/org/opensearch/cluster/LocalNodeMasterListener.java
index 1c35f7bbbe8a1..eb9bfa67686b6 100644
--- a/server/src/main/java/org/opensearch/cluster/LocalNodeMasterListener.java
+++ b/server/src/main/java/org/opensearch/cluster/LocalNodeMasterListener.java
@@ -6,55 +6,45 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster;
 
 /**
- * Enables listening to master changes events of the local node (when the local node becomes the master, and when the local
- * node cease being a master).
+ * Enables listening to cluster-manager changes events of the local node (when the local node becomes the cluster-manager, and when the local
+ * node cease being a cluster-manager).
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link LocalNodeClusterManagerListener}
  */
-public interface LocalNodeMasterListener extends ClusterStateListener {
+@Deprecated
+public interface LocalNodeMasterListener extends LocalNodeClusterManagerListener {
 
     /**
-     * Called when local node is elected to be the master
+     * Called when local node is elected to be the cluster-manager.
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #onClusterManager()}
      */
+    @Deprecated
     void onMaster();
 
     /**
-     * Called when the local node used to be the master, a new master was elected and it's no longer the local node.
+     * Called when the local node used to be the cluster-manager, a new cluster-manager was elected and it's no longer the local node.
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #offClusterManager()}
      */
+    @Deprecated
     void offMaster();
 
+    /**
+     * Called when local node is elected to be the cluster-manager.
+     */
+    @Override
+    default void onClusterManager() {
+        onMaster();
+    }
+
+    /**
+     * Called when the local node used to be the cluster-manager, a new cluster-manager was elected and it's no longer the local node.
+     */
     @Override
-    default void clusterChanged(ClusterChangedEvent event) {
-        final boolean wasMaster = event.previousState().nodes().isLocalNodeElectedMaster();
-        final boolean isMaster = event.localNodeMaster();
-        if (wasMaster == false && isMaster) {
-            onMaster();
-        } else if (wasMaster && isMaster == false) {
-            offMaster();
-        }
+    default void offClusterManager() {
+        offMaster();
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/MasterNodeChangePredicate.java b/server/src/main/java/org/opensearch/cluster/MasterNodeChangePredicate.java
index 9d11fb84af801..2395f81d2d504 100644
--- a/server/src/main/java/org/opensearch/cluster/MasterNodeChangePredicate.java
+++ b/server/src/main/java/org/opensearch/cluster/MasterNodeChangePredicate.java
@@ -6,61 +6,24 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster;
 
-import org.opensearch.cluster.node.DiscoveryNode;
-
 import java.util.function.Predicate;
 
+/**
+ * Utility class to build a predicate that accepts cluster state changes
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link ClusterManagerNodeChangePredicate}
+ */
+@Deprecated
 public final class MasterNodeChangePredicate {
 
     private MasterNodeChangePredicate() {
 
     }
 
-    /**
-     * builds a predicate that will accept a cluster state only if it was generated after the current has
-     * (re-)joined the master
-     */
     public static Predicate<ClusterState> build(ClusterState currentState) {
-        final long currentVersion = currentState.version();
-        final DiscoveryNode masterNode = currentState.nodes().getMasterNode();
-        final String currentMasterId = masterNode == null ? null : masterNode.getEphemeralId();
-        return newState -> {
-            final DiscoveryNode newMaster = newState.nodes().getMasterNode();
-            final boolean accept;
-            if (newMaster == null) {
-                accept = false;
-            } else if (newMaster.getEphemeralId().equals(currentMasterId) == false) {
-                accept = true;
-            } else {
-                accept = newState.version() > currentVersion;
-            }
-            return accept;
-        };
+        return ClusterManagerNodeChangePredicate.build(currentState);
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/MergableCustomMetadata.java b/server/src/main/java/org/opensearch/cluster/MergableCustomMetadata.java
index 521fbe52848f8..b9898e79e3e6f 100644
--- a/server/src/main/java/org/opensearch/cluster/MergableCustomMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/MergableCustomMetadata.java
@@ -40,6 +40,8 @@
  * Custom metadata can be merged using {@link #merge(Metadata.Custom)}.
  *
  * @param <T> type of custom meta data
+ *
+ * @opensearch.internal
  */
 public interface MergableCustomMetadata<T extends Metadata.Custom> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/NamedDiff.java b/server/src/main/java/org/opensearch/cluster/NamedDiff.java
index 7ab73b965188c..ce971aa723394 100644
--- a/server/src/main/java/org/opensearch/cluster/NamedDiff.java
+++ b/server/src/main/java/org/opensearch/cluster/NamedDiff.java
@@ -33,10 +33,12 @@
 package org.opensearch.cluster;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteable;
 
 /**
  * Diff that also support NamedWriteable interface
+ *
+ * @opensearch.internal
  */
 public interface NamedDiff<T extends Diffable<T>> extends Diff<T>, NamedWriteable {
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/NamedDiffable.java b/server/src/main/java/org/opensearch/cluster/NamedDiffable.java
index 7073053d1d840..ee73666d8b3b2 100644
--- a/server/src/main/java/org/opensearch/cluster/NamedDiffable.java
+++ b/server/src/main/java/org/opensearch/cluster/NamedDiffable.java
@@ -32,9 +32,11 @@
 
 package org.opensearch.cluster;
 
-import org.opensearch.common.io.stream.VersionedNamedWriteable;
+import org.opensearch.core.common.io.stream.VersionedNamedWriteable;
 
 /**
  * Diff that also support {@link VersionedNamedWriteable} interface
+ *
+ * @opensearch.internal
  */
 public interface NamedDiffable<T> extends Diffable<T>, VersionedNamedWriteable {}
diff --git a/server/src/main/java/org/opensearch/cluster/NamedDiffableValueSerializer.java b/server/src/main/java/org/opensearch/cluster/NamedDiffableValueSerializer.java
index d7bd39de42884..f5ee364078361 100644
--- a/server/src/main/java/org/opensearch/cluster/NamedDiffableValueSerializer.java
+++ b/server/src/main/java/org/opensearch/cluster/NamedDiffableValueSerializer.java
@@ -33,12 +33,14 @@
 package org.opensearch.cluster;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Value Serializer for named diffables
+ *
+ * @opensearch.internal
  */
 public class NamedDiffableValueSerializer<T extends NamedDiffable<T>> extends DiffableUtils.DiffableValueSerializer<String, T> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/NodeConnectionsService.java b/server/src/main/java/org/opensearch/cluster/NodeConnectionsService.java
index 02139ea21b483..5b7bb19a935b1 100644
--- a/server/src/main/java/org/opensearch/cluster/NodeConnectionsService.java
+++ b/server/src/main/java/org/opensearch/cluster/NodeConnectionsService.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.action.support.PlainListenableActionFuture;
 import org.opensearch.cluster.coordination.FollowersChecker;
@@ -44,12 +43,13 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterApplier;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -69,7 +69,7 @@
  * This component is responsible for maintaining connections from this node to all the nodes listed in the cluster state, and for
  * disconnecting from nodes once they are removed from the cluster state. It periodically checks that all connections are still open and
  * restores them if needed. Note that this component is *not* responsible for removing nodes from the cluster state if they disconnect or
- * are unresponsive: this is the job of the master's fault detection components, particularly {@link FollowersChecker}.
+ * are unresponsive: this is the job of the cluster-manager's fault detection components, particularly {@link FollowersChecker}.
  * <p>
  * The {@link NodeConnectionsService#connectToNodes(DiscoveryNodes, Runnable)} and {@link
  * NodeConnectionsService#disconnectFromNodesExcept(DiscoveryNodes)} methods are called on the {@link ClusterApplier} thread. This component
@@ -80,6 +80,8 @@
  * <p>
  * This component does not block on disconnections at all, because a disconnection might need to wait for an ongoing (background) connection
  * attempt to complete first.
+ *
+ * @opensearch.internal
  */
 public class NodeConnectionsService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(NodeConnectionsService.class);
@@ -227,6 +229,11 @@ private void connectDisconnectedTargets(Runnable onCompletion) {
         runnables.forEach(Runnable::run);
     }
 
+    /**
+     * A connection checker.
+     *
+     * @opensearch.internal
+     */
     class ConnectionChecker extends AbstractRunnable {
         protected void doRun() {
             if (connectionChecker == this) {
@@ -309,6 +316,8 @@ private enum ActivityType {
      * Similarly if we are currently disconnecting and then {@link ConnectionTarget#connect(ActionListener)} is called then all
      * disconnection listeners are immediately removed for failure notification and a connection is started once the disconnection is
      * complete.
+     *
+     * @opensearch.internal
      */
     private class ConnectionTarget {
         private final DiscoveryNode discoveryNode;
diff --git a/server/src/main/java/org/opensearch/cluster/NotClusterManagerException.java b/server/src/main/java/org/opensearch/cluster/NotClusterManagerException.java
new file mode 100644
index 0000000000000..d96bb521f399e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/NotClusterManagerException.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+/**
+ * Thrown when a node join request or a cluster-manager ping reaches a node which is not
+ * currently acting as a cluster-manager or when a cluster state update task is to be executed
+ * on a node that is no longer cluster-manager.
+ *
+ * @opensearch.internal
+ */
+public class NotClusterManagerException extends OpenSearchException {
+
+    public NotClusterManagerException(String msg) {
+        super(msg);
+    }
+
+    public NotClusterManagerException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public Throwable fillInStackTrace() {
+        return this;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/NotMasterException.java b/server/src/main/java/org/opensearch/cluster/NotMasterException.java
index 61772aa13233b..823e65a0d52ff 100644
--- a/server/src/main/java/org/opensearch/cluster/NotMasterException.java
+++ b/server/src/main/java/org/opensearch/cluster/NotMasterException.java
@@ -6,42 +6,22 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster;
 
-import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
- * Thrown when a node join request or a master ping reaches a node which is not
- * currently acting as a master or when a cluster state update task is to be executed
- * on a node that is no longer master.
+ * Thrown when a node join request or a cluster-manager ping reaches a node which is not
+ * currently acting as a cluster-manager or when a cluster state update task is to be executed
+ * on a node that is no longer cluster-manager.
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link NotClusterManagerException}
  */
-public class NotMasterException extends OpenSearchException {
+@Deprecated
+public class NotMasterException extends NotClusterManagerException {
 
     public NotMasterException(String msg) {
         super(msg);
@@ -51,8 +31,4 @@ public NotMasterException(StreamInput in) throws IOException {
         super(in);
     }
 
-    @Override
-    public Throwable fillInStackTrace() {
-        return this;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/RepositoryCleanupInProgress.java b/server/src/main/java/org/opensearch/cluster/RepositoryCleanupInProgress.java
index bae464606c0f2..debfe43f1d2b1 100644
--- a/server/src/main/java/org/opensearch/cluster/RepositoryCleanupInProgress.java
+++ b/server/src/main/java/org/opensearch/cluster/RepositoryCleanupInProgress.java
@@ -33,11 +33,12 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.RepositoryOperation;
 
 import java.io.IOException;
@@ -45,6 +46,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Information passed during repository cleanup
+ *
+ * @opensearch.internal
+ */
 public final class RepositoryCleanupInProgress extends AbstractNamedDiffable<ClusterState.Custom> implements ClusterState.Custom {
 
     public static final RepositoryCleanupInProgress EMPTY = new RepositoryCleanupInProgress(Collections.emptyList());
@@ -104,7 +110,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
@@ -112,6 +118,11 @@ public Version getMinimalSupportedVersion() {
         return LegacyESVersion.V_7_4_0;
     }
 
+    /**
+     * Entry in the collection.
+     *
+     * @opensearch.internal
+     */
     public static final class Entry implements Writeable, RepositoryOperation {
 
         private final String repository;
diff --git a/server/src/main/java/org/opensearch/cluster/RestoreInProgress.java b/server/src/main/java/org/opensearch/cluster/RestoreInProgress.java
index 205084261f2a9..042a4743ca25d 100644
--- a/server/src/main/java/org/opensearch/cluster/RestoreInProgress.java
+++ b/server/src/main/java/org/opensearch/cluster/RestoreInProgress.java
@@ -32,28 +32,29 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState.Custom;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.snapshots.Snapshot;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.UUID;
 
 /**
  * Meta data about restore processes that are currently executing
+ *
+ * @opensearch.internal
  */
 public class RestoreInProgress extends AbstractNamedDiffable<Custom> implements Custom, Iterable<RestoreInProgress.Entry> {
 
@@ -64,17 +65,17 @@ public class RestoreInProgress extends AbstractNamedDiffable<Custom> implements
 
     public static final String TYPE = "restore";
 
-    public static final RestoreInProgress EMPTY = new RestoreInProgress(ImmutableOpenMap.of());
+    public static final RestoreInProgress EMPTY = new RestoreInProgress(Map.of());
 
-    private final ImmutableOpenMap<String, Entry> entries;
+    private final Map<String, Entry> entries;
 
     /**
      * Constructs new restore metadata
      *
      * @param entries map of currently running restore processes keyed by their restore uuid
      */
-    private RestoreInProgress(ImmutableOpenMap<String, Entry> entries) {
-        this.entries = entries;
+    private RestoreInProgress(final Map<String, Entry> entries) {
+        this.entries = Collections.unmodifiableMap(entries);
     }
 
     @Override
@@ -92,7 +93,7 @@ public int hashCode() {
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder("RestoreInProgress[");
-        entries.forEach(entry -> builder.append("{").append(entry.key).append("}{").append(entry.value.snapshot).append("},"));
+        entries.forEach((s, entry) -> builder.append("{").append(s).append("}{").append(entry.snapshot).append("},"));
         builder.setCharAt(builder.length() - 1, ']');
         return builder.toString();
     }
@@ -107,12 +108,17 @@ public boolean isEmpty() {
 
     @Override
     public Iterator<Entry> iterator() {
-        return entries.valuesIt();
+        return entries.values().iterator();
     }
 
+    /**
+     * Builder of the restore.
+     *
+     * @opensearch.internal
+     */
     public static final class Builder {
 
-        private final ImmutableOpenMap.Builder<String, Entry> entries = ImmutableOpenMap.builder();
+        private final Map<String, Entry> entries = new HashMap<>();
 
         public Builder() {}
 
@@ -126,18 +132,20 @@ public Builder add(Entry entry) {
         }
 
         public RestoreInProgress build() {
-            return entries.isEmpty() ? EMPTY : new RestoreInProgress(entries.build());
+            return entries.isEmpty() ? EMPTY : new RestoreInProgress(entries);
         }
     }
 
     /**
      * Restore metadata
+     *
+     * @opensearch.internal
      */
     public static class Entry {
         private final String uuid;
         private final State state;
         private final Snapshot snapshot;
-        private final ImmutableOpenMap<ShardId, ShardRestoreStatus> shards;
+        private final Map<ShardId, ShardRestoreStatus> shards;
         private final List<String> indices;
 
         /**
@@ -149,20 +157,14 @@ public static class Entry {
          * @param indices    list of indices being restored
          * @param shards     map of shards being restored to their current restore status
          */
-        public Entry(
-            String uuid,
-            Snapshot snapshot,
-            State state,
-            List<String> indices,
-            ImmutableOpenMap<ShardId, ShardRestoreStatus> shards
-        ) {
+        public Entry(String uuid, Snapshot snapshot, State state, List<String> indices, final Map<ShardId, ShardRestoreStatus> shards) {
             this.snapshot = Objects.requireNonNull(snapshot);
             this.state = Objects.requireNonNull(state);
             this.indices = Objects.requireNonNull(indices);
             if (shards == null) {
-                this.shards = ImmutableOpenMap.of();
+                this.shards = Map.of();
             } else {
-                this.shards = shards;
+                this.shards = Collections.unmodifiableMap(shards);
             }
             this.uuid = Objects.requireNonNull(uuid);
         }
@@ -189,7 +191,7 @@ public Snapshot snapshot() {
          *
          * @return list of shards
          */
-        public ImmutableOpenMap<ShardId, ShardRestoreStatus> shards() {
+        public Map<ShardId, ShardRestoreStatus> shards() {
             return this.shards;
         }
 
@@ -235,6 +237,8 @@ public int hashCode() {
 
     /**
      * Represents status of a restored shard
+     *
+     * @opensearch.internal
      */
     public static class ShardRestoreStatus implements Writeable {
         private State state;
@@ -358,6 +362,8 @@ public int hashCode() {
 
     /**
      * Shard restore process state
+     *
+     * @opensearch.internal
      */
     public enum State {
         /**
@@ -447,7 +453,7 @@ public static NamedDiff<Custom> readDiffFrom(StreamInput in) throws IOException
 
     public RestoreInProgress(StreamInput in) throws IOException {
         int count = in.readVInt();
-        final ImmutableOpenMap.Builder<String, Entry> entriesBuilder = ImmutableOpenMap.builder(count);
+        final Map<String, Entry> entriesBuilder = new HashMap<>(count);
         for (int i = 0; i < count; i++) {
             final String uuid;
             uuid = in.readString();
@@ -461,31 +467,30 @@ public RestoreInProgress(StreamInput in) throws IOException {
                     snapshot,
                     state,
                     Collections.unmodifiableList(indexBuilder),
-                    in.readImmutableMap(ShardId::new, ShardRestoreStatus::readShardRestoreStatus)
+                    in.readMap(ShardId::new, ShardRestoreStatus::readShardRestoreStatus)
                 )
             );
         }
-        this.entries = entriesBuilder.build();
+        this.entries = Collections.unmodifiableMap(entriesBuilder);
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeVInt(entries.size());
-        for (ObjectCursor<Entry> v : entries.values()) {
-            Entry entry = v.value;
+        for (final Entry entry : entries.values()) {
             out.writeString(entry.uuid);
             entry.snapshot().writeTo(out);
             out.writeByte(entry.state().value());
             out.writeStringCollection(entry.indices);
-            out.writeMap(entry.shards);
+            out.writeMap(entry.shards, (o, shardId) -> shardId.writeTo(o), (o, status) -> status.writeTo(o));
         }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
         builder.startArray("snapshots");
-        for (ObjectCursor<Entry> entry : entries.values()) {
-            toXContent(entry.value, builder);
+        for (final Entry entry : entries.values()) {
+            toXContent(entry, builder);
         }
         builder.endArray();
         return builder;
@@ -511,9 +516,9 @@ public void toXContent(Entry entry, XContentBuilder builder) throws IOException
         builder.endArray();
         builder.startArray("shards");
         {
-            for (ObjectObjectCursor<ShardId, ShardRestoreStatus> shardEntry : entry.shards) {
-                ShardId shardId = shardEntry.key;
-                ShardRestoreStatus status = shardEntry.value;
+            for (final Map.Entry<ShardId, ShardRestoreStatus> shardEntry : entry.shards.entrySet()) {
+                ShardId shardId = shardEntry.getKey();
+                ShardRestoreStatus status = shardEntry.getValue();
                 builder.startObject();
                 {
                     builder.field("index", shardId.getIndex());
diff --git a/server/src/main/java/org/opensearch/cluster/SnapshotDeletionsInProgress.java b/server/src/main/java/org/opensearch/cluster/SnapshotDeletionsInProgress.java
index 67ba285f45130..247eb7a195ca7 100644
--- a/server/src/main/java/org/opensearch/cluster/SnapshotDeletionsInProgress.java
+++ b/server/src/main/java/org/opensearch/cluster/SnapshotDeletionsInProgress.java
@@ -36,11 +36,11 @@
 import org.opensearch.cluster.ClusterState.Custom;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.RepositoryOperation;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
@@ -57,6 +57,8 @@
 
 /**
  * A class that represents the snapshot deletions that are in progress in the cluster.
+ *
+ * @opensearch.internal
  */
 public class SnapshotDeletionsInProgress extends AbstractNamedDiffable<Custom> implements Custom {
 
@@ -217,6 +219,8 @@ public String toString() {
 
     /**
      * A class representing a snapshot deletion request entry in the cluster state.
+     *
+     * @opensearch.internal
      */
     public static final class Entry implements Writeable, RepositoryOperation {
         private final List<SnapshotId> snapshots;
@@ -373,6 +377,11 @@ public String toString() {
         }
     }
 
+    /**
+     * State of the deletions.
+     *
+     * @opensearch.internal
+     */
     public enum State implements Writeable {
 
         /**
diff --git a/server/src/main/java/org/opensearch/cluster/SnapshotsInProgress.java b/server/src/main/java/org/opensearch/cluster/SnapshotsInProgress.java
index 2c001833f46ce..10e714b08d138 100644
--- a/server/src/main/java/org/opensearch/cluster/SnapshotsInProgress.java
+++ b/server/src/main/java/org/opensearch/cluster/SnapshotsInProgress.java
@@ -32,22 +32,19 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.ObjectContainer;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState.Custom;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoryOperation;
 import org.opensearch.repositories.RepositoryShardId;
@@ -57,6 +54,7 @@
 import org.opensearch.snapshots.SnapshotsService;
 
 import java.io.IOException;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -71,6 +69,8 @@
 
 /**
  * Meta data about snapshots that are currently executing
+ *
+ * @opensearch.internal
  */
 public class SnapshotsInProgress extends AbstractNamedDiffable<Custom> implements Custom {
 
@@ -118,9 +118,10 @@ public static Entry startedEntry(
         List<String> dataStreams,
         long startTime,
         long repositoryStateId,
-        ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
+        final Map<ShardId, ShardSnapshotStatus> shards,
         Map<String, Object> userMetadata,
-        Version version
+        Version version,
+        boolean remoteStoreIndexShallowCopy
     ) {
         return new SnapshotsInProgress.Entry(
             snapshot,
@@ -134,7 +135,8 @@ public static Entry startedEntry(
             shards,
             null,
             userMetadata,
-            version
+            version,
+            remoteStoreIndexShallowCopy
         );
     }
 
@@ -166,24 +168,32 @@ public static Entry startClone(
             Collections.emptyList(),
             startTime,
             repositoryStateId,
-            ImmutableOpenMap.of(),
+            Map.of(),
             null,
             Collections.emptyMap(),
             version,
             source,
-            ImmutableOpenMap.of()
+            Map.of(),
+            false // initialising to false, will be updated in startCloning method of SnapshotsService while updating entry with
+                  // clone jobs
         );
     }
 
+    /**
+     * Entry in the collection.
+     *
+     * @opensearch.internal
+     */
     public static class Entry implements Writeable, ToXContent, RepositoryOperation {
         private final State state;
         private final Snapshot snapshot;
         private final boolean includeGlobalState;
+        private final boolean remoteStoreIndexShallowCopy;
         private final boolean partial;
         /**
          * Map of {@link ShardId} to {@link ShardSnapshotStatus} tracking the state of each shard snapshot operation.
          */
-        private final ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards;
+        private final Map<ShardId, ShardSnapshotStatus> shards;
         private final List<IndexId> indices;
         private final List<String> dataStreams;
         private final long startTime;
@@ -201,7 +211,7 @@ public static class Entry implements Writeable, ToXContent, RepositoryOperation
          * Map of {@link RepositoryShardId} to {@link ShardSnapshotStatus} tracking the state of each shard clone operation in this entry
          * the same way {@link #shards} tracks the status of each shard snapshot operation in non-clone entries.
          */
-        private final ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> clones;
+        private final Map<RepositoryShardId, ShardSnapshotStatus> clones;
 
         @Nullable
         private final Map<String, Object> userMetadata;
@@ -218,10 +228,11 @@ public Entry(
             List<String> dataStreams,
             long startTime,
             long repositoryStateId,
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
+            final Map<ShardId, ShardSnapshotStatus> shards,
             String failure,
             Map<String, Object> userMetadata,
-            Version version
+            Version version,
+            boolean remoteStoreIndexShallowCopy
         ) {
             this(
                 snapshot,
@@ -237,7 +248,8 @@ public Entry(
                 userMetadata,
                 version,
                 null,
-                ImmutableOpenMap.of()
+                Map.of(),
+                remoteStoreIndexShallowCopy
             );
         }
 
@@ -250,12 +262,13 @@ private Entry(
             List<String> dataStreams,
             long startTime,
             long repositoryStateId,
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
+            final Map<ShardId, ShardSnapshotStatus> shards,
             String failure,
-            Map<String, Object> userMetadata,
+            final Map<String, Object> userMetadata,
             Version version,
             @Nullable SnapshotId source,
-            @Nullable ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> clones
+            @Nullable final Map<RepositoryShardId, ShardSnapshotStatus> clones,
+            boolean remoteStoreIndexShallowCopy
         ) {
             this.state = state;
             this.snapshot = snapshot;
@@ -264,7 +277,7 @@ private Entry(
             this.indices = indices;
             this.dataStreams = dataStreams;
             this.startTime = startTime;
-            this.shards = shards;
+            this.shards = Collections.unmodifiableMap(shards);
             this.repositoryStateId = repositoryStateId;
             this.failure = failure;
             this.userMetadata = userMetadata;
@@ -272,10 +285,11 @@ private Entry(
             this.source = source;
             if (source == null) {
                 assert clones == null || clones.isEmpty() : "Provided [" + clones + "] but no source";
-                this.clones = ImmutableOpenMap.of();
+                this.clones = Map.of();
             } else {
-                this.clones = clones;
+                this.clones = Collections.unmodifiableMap(clones);
             }
+            this.remoteStoreIndexShallowCopy = remoteStoreIndexShallowCopy;
             assert assertShardsConsistent(this.source, this.state, this.indices, this.shards, this.clones);
         }
 
@@ -286,7 +300,7 @@ private Entry(StreamInput in) throws IOException {
             state = State.fromValue(in.readByte());
             indices = in.readList(IndexId::new);
             startTime = in.readLong();
-            shards = in.readImmutableMap(ShardId::new, ShardSnapshotStatus::readFrom);
+            shards = in.readMap(ShardId::new, ShardSnapshotStatus::readFrom);
             repositoryStateId = in.readLong();
             failure = in.readOptionalString();
             if (in.getVersion().onOrAfter(METADATA_FIELD_INTRODUCED)) {
@@ -295,11 +309,11 @@ private Entry(StreamInput in) throws IOException {
                 userMetadata = null;
             }
             if (in.getVersion().onOrAfter(VERSION_IN_SNAPSHOT_VERSION)) {
-                version = Version.readVersion(in);
+                version = in.readVersion();
             } else if (in.getVersion().onOrAfter(SnapshotsService.SHARD_GEN_IN_REPO_DATA_VERSION)) {
-                // If an older master informs us that shard generations are supported we use the minimum shard generation compatible
-                // version. If shard generations are not supported yet we use a placeholder for a version that does not use shard
-                // generations.
+                // If an older cluster-manager informs us that shard generations are supported
+                // we use the minimum shard generation compatible version.
+                // If shard generations are not supported yet we use a placeholder for a version that does not use shard generations.
                 version = in.readBoolean() ? SnapshotsService.SHARD_GEN_IN_REPO_DATA_VERSION : SnapshotsService.OLD_SNAPSHOT_FORMAT;
             } else {
                 version = SnapshotsService.OLD_SNAPSHOT_FORMAT;
@@ -311,10 +325,15 @@ private Entry(StreamInput in) throws IOException {
             }
             if (in.getVersion().onOrAfter(SnapshotsService.CLONE_SNAPSHOT_VERSION)) {
                 source = in.readOptionalWriteable(SnapshotId::new);
-                clones = in.readImmutableMap(RepositoryShardId::new, ShardSnapshotStatus::readFrom);
+                clones = in.readMap(RepositoryShardId::new, ShardSnapshotStatus::readFrom);
             } else {
                 source = null;
-                clones = ImmutableOpenMap.of();
+                clones = Map.of();
+            }
+            if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+                remoteStoreIndexShallowCopy = in.readBoolean();
+            } else {
+                remoteStoreIndexShallowCopy = false;
             }
         }
 
@@ -322,17 +341,17 @@ private static boolean assertShardsConsistent(
             SnapshotId source,
             State state,
             List<IndexId> indices,
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
-            ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> clones
+            final Map<ShardId, ShardSnapshotStatus> shards,
+            final Map<RepositoryShardId, ShardSnapshotStatus> clones
         ) {
             if ((state == State.INIT || state == State.ABORTED) && shards.isEmpty()) {
                 return true;
             }
             final Set<String> indexNames = indices.stream().map(IndexId::getName).collect(Collectors.toSet());
             final Set<String> indexNamesInShards = new HashSet<>();
-            shards.iterator().forEachRemaining(s -> {
-                indexNamesInShards.add(s.key.getIndexName());
-                assert source == null || s.value.nodeId == null
+            shards.entrySet().forEach(s -> {
+                indexNamesInShards.add(s.getKey().getIndexName());
+                assert source == null || s.getValue().nodeId == null
                     : "Shard snapshot must not be assigned to data node when copying from snapshot [" + source + "]";
             });
             assert source == null || indexNames.isEmpty() == false : "No empty snapshot clones allowed";
@@ -368,9 +387,10 @@ public Entry(
             List<String> dataStreams,
             long startTime,
             long repositoryStateId,
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
+            final Map<ShardId, ShardSnapshotStatus> shards,
             Map<String, Object> userMetadata,
-            Version version
+            Version version,
+            boolean remoteStoreIndexShallowCopy
         ) {
             this(
                 snapshot,
@@ -384,7 +404,8 @@ public Entry(
                 shards,
                 null,
                 userMetadata,
-                version
+                version,
+                remoteStoreIndexShallowCopy
             );
         }
 
@@ -393,7 +414,7 @@ public Entry(
             State state,
             List<IndexId> indices,
             long repositoryStateId,
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards,
+            final Map<ShardId, ShardSnapshotStatus> shards,
             Version version,
             String failure
         ) {
@@ -409,7 +430,8 @@ public Entry(
                 shards,
                 failure,
                 entry.userMetadata,
-                version
+                version,
+                entry.remoteStoreIndexShallowCopy
             );
         }
 
@@ -433,11 +455,12 @@ public Entry withRepoGen(long newRepoGen) {
                 userMetadata,
                 version,
                 source,
-                clones
+                clones,
+                remoteStoreIndexShallowCopy
             );
         }
 
-        public Entry withClones(ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> updatedClones) {
+        public Entry withClones(final Map<RepositoryShardId, ShardSnapshotStatus> updatedClones) {
             if (updatedClones.equals(clones)) {
                 return this;
             }
@@ -455,7 +478,28 @@ public Entry withClones(ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus>
                 userMetadata,
                 version,
                 source,
-                updatedClones
+                updatedClones,
+                remoteStoreIndexShallowCopy
+            );
+        }
+
+        public Entry withRemoteStoreIndexShallowCopy(final boolean remoteStoreIndexShallowCopy) {
+            return new Entry(
+                snapshot,
+                includeGlobalState,
+                partial,
+                state,
+                indices,
+                dataStreams,
+                startTime,
+                repositoryStateId,
+                shards,
+                failure,
+                userMetadata,
+                version,
+                source,
+                clones,
+                remoteStoreIndexShallowCopy
             );
         }
 
@@ -471,11 +515,11 @@ public Entry withClones(ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus>
          */
         @Nullable
         public Entry abort() {
-            final ImmutableOpenMap.Builder<ShardId, ShardSnapshotStatus> shardsBuilder = ImmutableOpenMap.builder();
+            final Map<ShardId, ShardSnapshotStatus> shardsBuilder = new HashMap<>();
             boolean completed = true;
             boolean allQueued = true;
-            for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : shards) {
-                ShardSnapshotStatus status = shardEntry.value;
+            for (final Map.Entry<ShardId, ShardSnapshotStatus> shardEntry : shards.entrySet()) {
+                ShardSnapshotStatus status = shardEntry.getValue();
                 allQueued &= status.state() == ShardState.QUEUED;
                 if (status.state().completed() == false) {
                     final String nodeId = status.nodeId();
@@ -487,15 +531,15 @@ public Entry abort() {
                     );
                 }
                 completed &= status.state().completed();
-                shardsBuilder.put(shardEntry.key, status);
+                shardsBuilder.put(shardEntry.getKey(), status);
             }
             if (allQueued) {
                 return null;
             }
-            return fail(shardsBuilder.build(), completed ? State.SUCCESS : State.ABORTED, ABORTED_FAILURE_TEXT);
+            return fail(shardsBuilder, completed ? State.SUCCESS : State.ABORTED, ABORTED_FAILURE_TEXT);
         }
 
-        public Entry fail(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards, State state, String failure) {
+        public Entry fail(final Map<ShardId, ShardSnapshotStatus> shards, State state, String failure) {
             return new Entry(
                 snapshot,
                 includeGlobalState,
@@ -510,7 +554,8 @@ public Entry fail(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards, State s
                 userMetadata,
                 version,
                 source,
-                clones
+                clones,
+                remoteStoreIndexShallowCopy
             );
         }
 
@@ -522,7 +567,7 @@ public Entry fail(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards, State s
          * @param shards new shard snapshot states
          * @return new snapshot entry
          */
-        public Entry withShardStates(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards) {
+        public Entry withShardStates(final Map<ShardId, ShardSnapshotStatus> shards) {
             if (completed(shards.values())) {
                 return new Entry(
                     snapshot,
@@ -536,7 +581,8 @@ public Entry withShardStates(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shar
                     shards,
                     failure,
                     userMetadata,
-                    version
+                    version,
+                    remoteStoreIndexShallowCopy
                 );
             }
             return withStartedShards(shards);
@@ -546,7 +592,7 @@ public Entry withShardStates(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shar
          * Same as {@link #withShardStates} but does not check if the snapshot completed and thus is only to be used when starting new
          * shard snapshots on data nodes for a running snapshot.
          */
-        public Entry withStartedShards(ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards) {
+        public Entry withStartedShards(final Map<ShardId, ShardSnapshotStatus> shards) {
             final SnapshotsInProgress.Entry updated = new Entry(
                 snapshot,
                 includeGlobalState,
@@ -559,7 +605,8 @@ public Entry withStartedShards(ImmutableOpenMap<ShardId, ShardSnapshotStatus> sh
                 shards,
                 failure,
                 userMetadata,
-                version
+                version,
+                remoteStoreIndexShallowCopy
             );
             assert updated.state().completed() == false && completed(updated.shards().values()) == false
                 : "Only running snapshots allowed but saw [" + updated + "]";
@@ -575,7 +622,7 @@ public Snapshot snapshot() {
             return this.snapshot;
         }
 
-        public ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards() {
+        public Map<ShardId, ShardSnapshotStatus> shards() {
             return this.shards;
         }
 
@@ -591,6 +638,10 @@ public boolean includeGlobalState() {
             return includeGlobalState;
         }
 
+        public boolean remoteStoreIndexShallowCopy() {
+            return remoteStoreIndexShallowCopy;
+        }
+
         public Map<String, Object> userMetadata() {
             return userMetadata;
         }
@@ -632,7 +683,7 @@ public boolean isClone() {
             return source != null;
         }
 
-        public ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> clones() {
+        public Map<RepositoryShardId, ShardSnapshotStatus> clones() {
             return clones;
         }
 
@@ -654,7 +705,7 @@ public boolean equals(Object o) {
             if (version.equals(entry.version) == false) return false;
             if (Objects.equals(source, ((Entry) o).source) == false) return false;
             if (clones.equals(((Entry) o).clones) == false) return false;
-
+            if (remoteStoreIndexShallowCopy != entry.remoteStoreIndexShallowCopy) return false;
             return true;
         }
 
@@ -671,12 +722,13 @@ public int hashCode() {
             result = 31 * result + version.hashCode();
             result = 31 * result + (source == null ? 0 : source.hashCode());
             result = 31 * result + clones.hashCode();
+            result = 31 * result + (remoteStoreIndexShallowCopy ? 1 : 0);
             return result;
         }
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
         @Override
@@ -699,9 +751,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field(REPOSITORY_STATE_ID, repositoryStateId);
             builder.startArray(SHARDS);
             {
-                for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : shards) {
-                    ShardId shardId = shardEntry.key;
-                    ShardSnapshotStatus status = shardEntry.value;
+                for (final Map.Entry<ShardId, ShardSnapshotStatus> shardEntry : shards.entrySet()) {
+                    ShardId shardId = shardEntry.getKey();
+                    ShardSnapshotStatus status = shardEntry.getValue();
                     builder.startObject();
                     {
                         builder.field(INDEX, shardId.getIndex());
@@ -726,14 +778,14 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeByte(state.value());
             out.writeList(indices);
             out.writeLong(startTime);
-            out.writeMap(shards);
+            out.writeMap(shards, (o, v) -> v.writeTo(o), (o, v) -> v.writeTo(o));
             out.writeLong(repositoryStateId);
             out.writeOptionalString(failure);
             if (out.getVersion().onOrAfter(METADATA_FIELD_INTRODUCED)) {
                 out.writeMap(userMetadata);
             }
             if (out.getVersion().onOrAfter(VERSION_IN_SNAPSHOT_VERSION)) {
-                Version.writeVersion(version, out);
+                out.writeVersion(version);
             } else if (out.getVersion().onOrAfter(SnapshotsService.SHARD_GEN_IN_REPO_DATA_VERSION)) {
                 out.writeBoolean(SnapshotsService.useShardGenerations(version));
             }
@@ -742,7 +794,10 @@ public void writeTo(StreamOutput out) throws IOException {
             }
             if (out.getVersion().onOrAfter(SnapshotsService.CLONE_SNAPSHOT_VERSION)) {
                 out.writeOptionalWriteable(source);
-                out.writeMap(clones);
+                out.writeMap(clones, (o, v) -> v.writeTo(o), (o, v) -> v.writeTo(o));
+            }
+            if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+                out.writeBoolean(remoteStoreIndexShallowCopy);
             }
         }
 
@@ -758,24 +813,29 @@ public boolean isFragment() {
      * @param shards list of shard statuses
      * @return true if all shards have completed (either successfully or failed), false otherwise
      */
-    public static boolean completed(ObjectContainer<ShardSnapshotStatus> shards) {
-        for (ObjectCursor<ShardSnapshotStatus> status : shards) {
-            if (status.value.state().completed == false) {
+    public static boolean completed(final Collection<ShardSnapshotStatus> shards) {
+        for (final ShardSnapshotStatus status : shards) {
+            if (status.state().completed == false) {
                 return false;
             }
         }
         return true;
     }
 
-    private static boolean hasFailures(ImmutableOpenMap<RepositoryShardId, ShardSnapshotStatus> clones) {
-        for (ObjectCursor<ShardSnapshotStatus> value : clones.values()) {
-            if (value.value.state().failed()) {
+    private static boolean hasFailures(final Map<RepositoryShardId, ShardSnapshotStatus> clones) {
+        for (final ShardSnapshotStatus value : clones.values()) {
+            if (value.state().failed()) {
                 return true;
             }
         }
         return false;
     }
 
+    /**
+     * Status of shard snapshots.
+     *
+     * @opensearch.internal
+     */
     public static class ShardSnapshotStatus implements Writeable {
 
         /**
@@ -911,6 +971,11 @@ public String toString() {
         }
     }
 
+    /**
+     * State of the snapshots.
+     *
+     * @opensearch.internal
+     */
     public enum State {
         INIT((byte) 0, false),
         STARTED((byte) 1, false),
@@ -958,9 +1023,9 @@ public static State fromValue(byte value) {
     private static boolean assertConsistentEntries(List<Entry> entries) {
         final Map<String, Set<ShardId>> assignedShardsByRepo = new HashMap<>();
         for (Entry entry : entries) {
-            for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shard : entry.shards()) {
-                if (shard.value.isActive()) {
-                    assert assignedShardsByRepo.computeIfAbsent(entry.repository(), k -> new HashSet<>()).add(shard.key)
+            for (final Map.Entry<ShardId, ShardSnapshotStatus> shard : entry.shards().entrySet()) {
+                if (shard.getValue().isActive()) {
+                    assert assignedShardsByRepo.computeIfAbsent(entry.repository(), k -> new HashSet<>()).add(shard.getKey())
                         : "Found duplicate shard assignments in " + entries;
                 }
             }
@@ -1048,6 +1113,11 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
         return builder;
     }
 
+    /**
+     * The shard state.
+     *
+     * @opensearch.internal
+     */
     public enum ShardState {
         INIT((byte) 0, false, false),
         SUCCESS((byte) 2, true, false),
diff --git a/server/src/main/java/org/opensearch/cluster/TimeoutClusterStateListener.java b/server/src/main/java/org/opensearch/cluster/TimeoutClusterStateListener.java
index d7465fa00a50c..eb31fa2b7e69d 100644
--- a/server/src/main/java/org/opensearch/cluster/TimeoutClusterStateListener.java
+++ b/server/src/main/java/org/opensearch/cluster/TimeoutClusterStateListener.java
@@ -37,7 +37,7 @@
 /**
  * An exception to cluster state listener that allows for timeouts and for post added notifications.
  *
- *
+ * @opensearch.internal
  */
 public interface TimeoutClusterStateListener extends ClusterStateListener {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ack/AckedRequest.java b/server/src/main/java/org/opensearch/cluster/ack/AckedRequest.java
index 23a9ed16e35d2..750f4b177cb86 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/AckedRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/AckedRequest.java
@@ -36,6 +36,8 @@
 
 /**
  * Identifies a cluster state update request with acknowledgement support
+ *
+ * @opensearch.internal
  */
 public interface AckedRequest {
 
@@ -45,7 +47,19 @@ public interface AckedRequest {
     TimeValue ackTimeout();
 
     /**
-     * Returns the timeout for the request to be completed on the master node
+     * Returns the timeout for the request to be completed on the cluster-manager node
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNodeTimeout()}
+     */
+    @Deprecated
+    default TimeValue masterNodeTimeout() {
+        throw new UnsupportedOperationException("Must be overridden");
+    }
+
+    /**
+     * Returns the timeout for the request to be completed on the cluster-manager node
      */
-    TimeValue masterNodeTimeout();
+    // TODO: Remove default implementation after removing the deprecated masterNodeTimeout()
+    default TimeValue clusterManagerNodeTimeout() {
+        return masterNodeTimeout();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateRequest.java
index d142c28086f70..dd5769d7c7f89 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateRequest.java
@@ -37,6 +37,8 @@
 /**
  * Base class to be used when needing to update the cluster state
  * Contains the basic fields that are always needed
+ *
+ * @opensearch.internal
  */
 public abstract class ClusterStateUpdateRequest<T extends ClusterStateUpdateRequest<T>> implements AckedRequest {
 
@@ -62,7 +64,7 @@ public T ackTimeout(TimeValue ackTimeout) {
 
     /**
      * Returns the maximum time interval to wait for the request to
-     * be completed on the master node
+     * be completed on the cluster-manager node
      */
     @Override
     public TimeValue masterNodeTimeout() {
@@ -70,7 +72,7 @@ public TimeValue masterNodeTimeout() {
     }
 
     /**
-     * Sets the master node timeout
+     * Sets the cluster-manager node timeout
      */
     @SuppressWarnings("unchecked")
     public T masterNodeTimeout(TimeValue masterNodeTimeout) {
diff --git a/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateResponse.java b/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateResponse.java
index 3a79e15380165..db26496c6f263 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateResponse.java
@@ -34,6 +34,8 @@
 
 /**
  * Base response returned after a cluster state update
+ *
+ * @opensearch.internal
  */
 public class ClusterStateUpdateResponse {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ack/CreateIndexClusterStateUpdateResponse.java b/server/src/main/java/org/opensearch/cluster/ack/CreateIndexClusterStateUpdateResponse.java
index 9c9beb1cd986e..52b04b9961ff8 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/CreateIndexClusterStateUpdateResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/CreateIndexClusterStateUpdateResponse.java
@@ -34,6 +34,8 @@
 
 /**
  * A cluster state update response with specific fields for index creation.
+ *
+ * @opensearch.internal
  */
 public class CreateIndexClusterStateUpdateResponse extends ClusterStateUpdateResponse {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ack/IndicesClusterStateUpdateRequest.java b/server/src/main/java/org/opensearch/cluster/ack/IndicesClusterStateUpdateRequest.java
index 7410378760a3a..d9753027ffc67 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/IndicesClusterStateUpdateRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/IndicesClusterStateUpdateRequest.java
@@ -31,10 +31,12 @@
 
 package org.opensearch.cluster.ack;
 
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 /**
  * Base cluster state update request that allows to execute update against multiple indices
+ *
+ * @opensearch.internal
  */
 public abstract class IndicesClusterStateUpdateRequest<T extends IndicesClusterStateUpdateRequest<T>> extends ClusterStateUpdateRequest<T> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ack/OpenIndexClusterStateUpdateResponse.java b/server/src/main/java/org/opensearch/cluster/ack/OpenIndexClusterStateUpdateResponse.java
index 70915ea162a8a..faf9e3e9bebbc 100644
--- a/server/src/main/java/org/opensearch/cluster/ack/OpenIndexClusterStateUpdateResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/ack/OpenIndexClusterStateUpdateResponse.java
@@ -33,6 +33,8 @@
 
 /**
  * A cluster state update response with specific fields for index opening.
+ *
+ * @opensearch.internal
  */
 public class OpenIndexClusterStateUpdateResponse extends ClusterStateUpdateResponse {
 
diff --git a/server/src/main/java/org/opensearch/cluster/ack/package-info.java b/server/src/main/java/org/opensearch/cluster/ack/package-info.java
new file mode 100644
index 0000000000000..e8206eeb37b26
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/ack/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Acknowledgment transport handlers. */
+package org.opensearch.cluster.ack;
diff --git a/server/src/main/java/org/opensearch/cluster/action/index/MappingUpdatedAction.java b/server/src/main/java/org/opensearch/cluster/action/index/MappingUpdatedAction.java
index f22d489ec6fd7..02f313d59d310 100644
--- a/server/src/main/java/org/opensearch/cluster/action/index/MappingUpdatedAction.java
+++ b/server/src/main/java/org/opensearch/cluster/action/index/MappingUpdatedAction.java
@@ -34,10 +34,9 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.mapping.put.AutoPutMappingAction;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.client.Client;
 import org.opensearch.client.IndicesAdminClient;
 import org.opensearch.cluster.service.ClusterService;
@@ -49,8 +48,9 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.RunOnce;
 import org.opensearch.common.util.concurrent.UncategorizedExecutionException;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.Mapping;
 
 import java.util.concurrent.Semaphore;
@@ -58,6 +58,8 @@
 /**
  * Called by shards in the cluster when their mapping was dynamically updated and it needs to be updated
  * in the cluster state meta data (and broadcast to all members).
+ *
+ * @opensearch.internal
  */
 public class MappingUpdatedAction {
 
@@ -104,12 +106,12 @@ public void setClient(Client client) {
     }
 
     /**
-     * Update mappings on the master node, waiting for the change to be committed,
+     * Update mappings on the cluster-manager node, waiting for the change to be committed,
      * but not for the mapping update to be applied on all nodes. The timeout specified by
-     * {@code timeout} is the master node timeout ({@link MasterNodeRequest#masterNodeTimeout()}),
-     * potentially waiting for a master node to be available.
+     * {@code timeout} is the cluster-manager node timeout ({@link ClusterManagerNodeRequest#clusterManagerNodeTimeout()}),
+     * potentially waiting for a cluster-manager node to be available.
      */
-    public void updateMappingOnMaster(Index index, Mapping mappingUpdate, ActionListener<Void> listener) {
+    public void updateMappingOnClusterManager(Index index, Mapping mappingUpdate, ActionListener<Void> listener) {
 
         final RunOnce release = new RunOnce(() -> semaphore.release());
         try {
@@ -130,6 +132,19 @@ public void updateMappingOnMaster(Index index, Mapping mappingUpdate, ActionList
         }
     }
 
+    /**
+     * Update mappings on the cluster-manager node, waiting for the change to be committed,
+     * but not for the mapping update to be applied on all nodes. The timeout specified by
+     * {@code timeout} is the cluster-manager node timeout ({@link ClusterManagerNodeRequest#clusterManagerNodeTimeout()}),
+     * potentially waiting for a cluster-manager node to be available.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #updateMappingOnClusterManager(Index, Mapping, ActionListener)}
+     */
+    @Deprecated
+    public void updateMappingOnMaster(Index index, Mapping mappingUpdate, ActionListener<Void> listener) {
+        updateMappingOnClusterManager(index, mappingUpdate, listener);
+    }
+
     // used by tests
     int blockedThreads() {
         return semaphore.getQueueLength();
@@ -139,8 +154,8 @@ int blockedThreads() {
     protected void sendUpdateMapping(Index index, Mapping mappingUpdate, ActionListener<Void> listener) {
         PutMappingRequest putMappingRequest = new PutMappingRequest();
         putMappingRequest.setConcreteIndex(index);
-        putMappingRequest.source(mappingUpdate.toString(), XContentType.JSON);
-        putMappingRequest.masterNodeTimeout(dynamicMappingUpdateTimeout);
+        putMappingRequest.source(mappingUpdate.toString(), MediaTypeRegistry.JSON);
+        putMappingRequest.clusterManagerNodeTimeout(dynamicMappingUpdateTimeout);
         putMappingRequest.timeout(TimeValue.ZERO);
         if (clusterService.state().nodes().getMinNodeVersion().onOrAfter(LegacyESVersion.V_7_9_0)) {
             client.execute(
@@ -169,6 +184,11 @@ private static RuntimeException unwrapEsException(OpenSearchException esEx) {
         return new UncategorizedExecutionException("Failed execution", root);
     }
 
+    /**
+     * An adjustable semaphore
+     *
+     * @opensearch.internal
+     */
     static class AdjustableSemaphore extends Semaphore {
 
         private final Object maxPermitsMutex = new Object();
diff --git a/server/src/main/java/org/opensearch/cluster/action/index/NodeMappingRefreshAction.java b/server/src/main/java/org/opensearch/cluster/action/index/NodeMappingRefreshAction.java
index 23ce218904d21..fe4793171b428 100644
--- a/server/src/main/java/org/opensearch/cluster/action/index/NodeMappingRefreshAction.java
+++ b/server/src/main/java/org/opensearch/cluster/action/index/NodeMappingRefreshAction.java
@@ -40,19 +40,24 @@
 import org.opensearch.cluster.metadata.MetadataMappingService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.EmptyTransportResponseHandler;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
+/**
+ * Transport action for refreshing the Node Mapping
+ *
+ * @opensearch.internal
+ */
 public class NodeMappingRefreshAction {
 
     private static final Logger logger = LogManager.getLogger(NodeMappingRefreshAction.class);
@@ -74,14 +79,19 @@ public NodeMappingRefreshAction(TransportService transportService, MetadataMappi
         );
     }
 
-    public void nodeMappingRefresh(final DiscoveryNode masterNode, final NodeMappingRefreshRequest request) {
-        if (masterNode == null) {
-            logger.warn("can't send mapping refresh for [{}], no master known.", request.index());
+    public void nodeMappingRefresh(final DiscoveryNode clusterManagerNode, final NodeMappingRefreshRequest request) {
+        if (clusterManagerNode == null) {
+            logger.warn("can't send mapping refresh for [{}], no cluster-manager known.", request.index());
             return;
         }
-        transportService.sendRequest(masterNode, ACTION_NAME, request, EmptyTransportResponseHandler.INSTANCE_SAME);
+        transportService.sendRequest(clusterManagerNode, ACTION_NAME, request, EmptyTransportResponseHandler.INSTANCE_SAME);
     }
 
+    /**
+     * A handler for a node mapping refresh transport request.
+     *
+     * @opensearch.internal
+     */
     private class NodeMappingRefreshTransportHandler implements TransportRequestHandler<NodeMappingRefreshRequest> {
 
         @Override
@@ -91,6 +101,11 @@ public void messageReceived(NodeMappingRefreshRequest request, TransportChannel
         }
     }
 
+    /**
+     * Request to refresh node mapping.
+     *
+     * @opensearch.internal
+     */
     public static class NodeMappingRefreshRequest extends TransportRequest implements IndicesRequest {
 
         private String index;
diff --git a/server/src/main/java/org/opensearch/cluster/action/index/package-info.java b/server/src/main/java/org/opensearch/cluster/action/index/package-info.java
new file mode 100644
index 0000000000000..3594d858b2970
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/action/index/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Index Action transport handlers. */
+package org.opensearch.cluster.action.index;
diff --git a/server/src/main/java/org/opensearch/cluster/action/package-info.java b/server/src/main/java/org/opensearch/cluster/action/package-info.java
new file mode 100644
index 0000000000000..acd8cf0f63592
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/action/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Action transport handlers. */
+package org.opensearch.cluster.action;
diff --git a/server/src/main/java/org/opensearch/cluster/action/shard/ShardStateAction.java b/server/src/main/java/org/opensearch/cluster/action/shard/ShardStateAction.java
index 300067587b78b..cb5749a91d448 100644
--- a/server/src/main/java/org/opensearch/cluster/action/shard/ShardStateAction.java
+++ b/server/src/main/java/org/opensearch/cluster/action/shard/ShardStateAction.java
@@ -35,17 +35,16 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterManagerNodeChangePredicate;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.ClusterStateTaskConfig;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.ClusterStateTaskListener;
-import org.opensearch.cluster.MasterNodeChangePredicate;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -58,11 +57,13 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -74,7 +75,6 @@
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestDeduplicator;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
@@ -87,6 +87,11 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+/**
+ * Transport action for retrieving the shard state
+ *
+ * @opensearch.internal
+ */
 public class ShardStateAction {
 
     private static final Logger logger = LogManager.getLogger(ShardStateAction.class);
@@ -177,14 +182,14 @@ private void sendShardAction(
         final ActionListener<Void> listener
     ) {
         ClusterStateObserver observer = new ClusterStateObserver(currentState, clusterService, null, logger, threadPool.getThreadContext());
-        DiscoveryNode masterNode = currentState.nodes().getMasterNode();
-        Predicate<ClusterState> changePredicate = MasterNodeChangePredicate.build(currentState);
-        if (masterNode == null) {
-            logger.warn("no master known for action [{}] for shard entry [{}]", actionName, request);
-            waitForNewMasterAndRetry(actionName, observer, request, listener, changePredicate);
+        DiscoveryNode clusterManagerNode = currentState.nodes().getClusterManagerNode();
+        Predicate<ClusterState> changePredicate = ClusterManagerNodeChangePredicate.build(currentState);
+        if (clusterManagerNode == null) {
+            logger.warn("no cluster-manager known for action [{}] for shard entry [{}]", actionName, request);
+            waitForNewClusterManagerAndRetry(actionName, observer, request, listener, changePredicate);
         } else {
-            logger.debug("sending [{}] to [{}] for shard entry [{}]", actionName, masterNode.getId(), request);
-            transportService.sendRequest(masterNode, actionName, request, new EmptyTransportResponseHandler(ThreadPool.Names.SAME) {
+            logger.debug("sending [{}] to [{}] for shard entry [{}]", actionName, clusterManagerNode.getId(), request);
+            transportService.sendRequest(clusterManagerNode, actionName, request, new EmptyTransportResponseHandler(ThreadPool.Names.SAME) {
                 @Override
                 public void handleResponse(TransportResponse.Empty response) {
                     listener.onResponse(null);
@@ -192,14 +197,14 @@ public void handleResponse(TransportResponse.Empty response) {
 
                 @Override
                 public void handleException(TransportException exp) {
-                    if (isMasterChannelException(exp)) {
-                        waitForNewMasterAndRetry(actionName, observer, request, listener, changePredicate);
+                    if (isClusterManagerChannelException(exp)) {
+                        waitForNewClusterManagerAndRetry(actionName, observer, request, listener, changePredicate);
                     } else {
                         logger.warn(
                             new ParameterizedMessage(
                                 "unexpected failure while sending request [{}]" + " to [{}] for shard entry [{}]",
                                 actionName,
-                                masterNode,
+                                clusterManagerNode,
                                 request
                             ),
                             exp
@@ -217,17 +222,17 @@ public void handleException(TransportException exp) {
         }
     }
 
-    private static Class[] MASTER_CHANNEL_EXCEPTIONS = new Class[] {
-        NotMasterException.class,
+    private static Class[] CLUSTER_MANAGER_CHANNEL_EXCEPTIONS = new Class[] {
+        NotClusterManagerException.class,
         ConnectTransportException.class,
         FailedToCommitClusterStateException.class };
 
-    private static boolean isMasterChannelException(TransportException exp) {
-        return ExceptionsHelper.unwrap(exp, MASTER_CHANNEL_EXCEPTIONS) != null;
+    private static boolean isClusterManagerChannelException(TransportException exp) {
+        return ExceptionsHelper.unwrap(exp, CLUSTER_MANAGER_CHANNEL_EXCEPTIONS) != null;
     }
 
     /**
-     * Send a shard failed request to the master node to update the cluster state with the failure of a shard on another node. This means
+     * Send a shard failed request to the cluster-manager node to update the cluster state with the failure of a shard on another node. This means
      * that the shard should be failed because a write made it into the primary but was not replicated to this shard copy. If the shard
      * does not exist anymore but still has an entry in the in-sync set, remove its allocation id from the in-sync set.
      *
@@ -261,7 +266,7 @@ int remoteShardFailedCacheSize() {
     }
 
     /**
-     * Send a shard failed request to the master node to update the cluster state when a shard on the local node failed.
+     * Send a shard failed request to the cluster-manager node to update the cluster state when a shard on the local node failed.
      */
     public void localShardFailed(
         final ShardRouting shardRouting,
@@ -273,7 +278,7 @@ public void localShardFailed(
     }
 
     /**
-     * Send a shard failed request to the master node to update the cluster state when a shard on the local node failed.
+     * Send a shard failed request to the cluster-manager node to update the cluster state when a shard on the local node failed.
      */
     public void localShardFailed(
         final ShardRouting shardRouting,
@@ -294,7 +299,7 @@ public void localShardFailed(
     }
 
     // visible for testing
-    protected void waitForNewMasterAndRetry(
+    protected void waitForNewClusterManagerAndRetry(
         String actionName,
         ClusterStateObserver observer,
         TransportRequest request,
@@ -305,7 +310,7 @@ protected void waitForNewMasterAndRetry(
             @Override
             public void onNewClusterState(ClusterState state) {
                 if (logger.isTraceEnabled()) {
-                    logger.trace("new cluster state [{}] after waiting for master election for shard entry [{}]", state, request);
+                    logger.trace("new cluster state [{}] after waiting for cluster-manager election for shard entry [{}]", state, request);
                 }
                 sendShardAction(actionName, state, request, listener);
             }
@@ -318,7 +323,7 @@ public void onClusterServiceClose() {
 
             @Override
             public void onTimeout(TimeValue timeout) {
-                // we wait indefinitely for a new master
+                // we wait indefinitely for a new cluster-manager
                 assert false;
             }
         }, changePredicate);
@@ -328,6 +333,11 @@ private void setFollowUpRerouteTaskPriority(Priority followUpRerouteTaskPriority
         this.followUpRerouteTaskPriority = followUpRerouteTaskPriority;
     }
 
+    /**
+     * A transport handler for a shard failed action.
+     *
+     * @opensearch.internal
+     */
     private static class ShardFailedTransportHandler implements TransportRequestHandler<FailedShardEntry> {
         private final ClusterService clusterService;
         private final ShardFailedClusterStateTaskExecutor shardFailedClusterStateTaskExecutor;
@@ -375,14 +385,14 @@ public void onFailure(String source, Exception e) {
                     }
 
                     @Override
-                    public void onNoLongerMaster(String source) {
-                        logger.error("{} no longer master while failing shard [{}]", request.shardId, request);
+                    public void onNoLongerClusterManager(String source) {
+                        logger.error("{} no longer cluster-manager while failing shard [{}]", request.shardId, request);
                         try {
-                            channel.sendResponse(new NotMasterException(source));
+                            channel.sendResponse(new NotClusterManagerException(source));
                         } catch (Exception channelException) {
                             logger.warn(
                                 () -> new ParameterizedMessage(
-                                    "{} failed to send no longer master while failing shard [{}]",
+                                    "{} failed to send no longer cluster-manager while failing shard [{}]",
                                     request.shardId,
                                     request
                                 ),
@@ -411,6 +421,11 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         }
     }
 
+    /**
+     * Executor if shard fails cluster state task.
+     *
+     * @opensearch.internal
+     */
     public static class ShardFailedClusterStateTaskExecutor implements ClusterStateTaskExecutor<FailedShardEntry> {
         private final AllocationService allocationService;
         private final RerouteService rerouteService;
@@ -547,6 +562,11 @@ public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {
         }
     }
 
+    /**
+     * Entry for a failed shard.
+     *
+     * @opensearch.internal
+     */
     public static class FailedShardEntry extends TransportRequest {
         final ShardId shardId;
         final String allocationId;
@@ -653,6 +673,11 @@ public void shardStarted(
         sendShardAction(SHARD_STARTED_ACTION_NAME, currentState, entry, listener);
     }
 
+    /**
+     * Handler for a shard started action.
+     *
+     * @opensearch.internal
+     */
     private static class ShardStartedTransportHandler implements TransportRequestHandler<StartedShardEntry> {
         private final ClusterService clusterService;
         private final ShardStartedClusterStateTaskExecutor shardStartedClusterStateTaskExecutor;
@@ -682,6 +707,11 @@ public void messageReceived(StartedShardEntry request, TransportChannel channel,
         }
     }
 
+    /**
+     * Executor for when shard starts cluster state.
+     *
+     * @opensearch.internal
+     */
     public static class ShardStartedClusterStateTaskExecutor
         implements
             ClusterStateTaskExecutor<StartedShardEntry>,
@@ -714,7 +744,8 @@ public ClusterTasksResult<StartedShardEntry> execute(ClusterState currentState,
                 if (matched == null) {
                     // tasks that correspond to non-existent shards are marked as successful. The reason is that we resend shard started
                     // events on every cluster state publishing that does not contain the shard as started yet. This means that old stale
-                    // requests might still be in flight even after the shard has already been started or failed on the master. We just
+                    // requests might still be in flight even after the shard has already been started or failed on the cluster-manager. We
+                    // just
                     // ignore these requests for now.
                     logger.debug("{} ignoring shard started task [{}] (shard does not exist anymore)", task.shardId, task);
                     builder.success(task);
@@ -786,7 +817,7 @@ public ClusterTasksResult<StartedShardEntry> execute(ClusterState currentState,
 
         @Override
         public void onFailure(String source, Exception e) {
-            if (e instanceof FailedToCommitClusterStateException || e instanceof NotMasterException) {
+            if (e instanceof FailedToCommitClusterStateException || e instanceof NotClusterManagerException) {
                 logger.debug(() -> new ParameterizedMessage("failure during [{}]", source), e);
             } else {
                 logger.error(() -> new ParameterizedMessage("unexpected failure during [{}]", source), e);
@@ -806,6 +837,11 @@ public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {
         }
     }
 
+    /**
+     * try for started shard.
+     *
+     * @opensearch.internal
+     */
     public static class StartedShardEntry extends TransportRequest {
         final ShardId shardId;
         final String allocationId;
@@ -849,6 +885,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Error thrown when a shard is no longer primary.
+     *
+     * @opensearch.internal
+     */
     public static class NoLongerPrimaryShardException extends OpenSearchException {
 
         public NoLongerPrimaryShardException(ShardId shardId, String msg) {
diff --git a/server/src/main/java/org/opensearch/cluster/action/shard/package-info.java b/server/src/main/java/org/opensearch/cluster/action/shard/package-info.java
new file mode 100644
index 0000000000000..5666176386d46
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/action/shard/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Shard State transport handlers. */
+package org.opensearch.cluster.action.shard;
diff --git a/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealth.java b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealth.java
new file mode 100644
index 0000000000000..eae79e2ac0986
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealth.java
@@ -0,0 +1,317 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * Cluster Awareness AttributeValue Health information
+ */
+public class ClusterAwarenessAttributeValueHealth implements Writeable, ToXContentFragment {
+
+    private static final String ACTIVE_SHARDS = "active_shards";
+    private static final String INITIALIZING_SHARDS = "initializing_shards";
+    private static final String RELOCATING_SHARDS = "relocating_shards";
+    private static final String UNASSIGNED_SHARDS = "unassigned_shards";
+    private static final String NODES = "data_nodes";
+    private static final String WEIGHTS = "weight";
+    private final String name;
+    private int activeShards;
+    private int unassignedShards;
+    private int initializingShards;
+    private int relocatingShards;
+    private int nodes;
+    private double weight;
+    private List<String> nodeList;
+
+    /**
+     * Creates Awareness AttributeValue Health information
+     *
+     * @param name name of awareness attribute
+     */
+    public ClusterAwarenessAttributeValueHealth(String name, List<String> nodeList) {
+        this.name = name;
+        this.nodeList = nodeList;
+    }
+
+    // Constructor use by Unit test case.
+    ClusterAwarenessAttributeValueHealth(
+        String name,
+        int activeShards,
+        int initializingShards,
+        int relocatingShards,
+        int unassignedShards,
+        int nodes,
+        double weights
+    ) {
+        this.name = name;
+        this.activeShards = activeShards;
+        this.initializingShards = initializingShards;
+        this.relocatingShards = relocatingShards;
+        this.unassignedShards = unassignedShards;
+        this.nodes = nodes;
+        this.weight = weights;
+    }
+
+    public ClusterAwarenessAttributeValueHealth(final StreamInput in) throws IOException {
+        name = in.readString();
+        activeShards = in.readVInt();
+        initializingShards = in.readVInt();
+        relocatingShards = in.readVInt();
+        unassignedShards = in.readVInt();
+        nodes = in.readVInt();
+        weight = in.readDouble();
+    }
+
+    public static ClusterAwarenessAttributeValueHealth fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        XContentParser.Token token = parser.nextToken();
+        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        String attributeName = parser.currentName();
+        int active_shards = 0;
+        int initializing_shards = 0;
+        int relocating_shards = 0;
+        int unassigned_shards = 0;
+        int nodes = 0;
+        double weight = 0.0;
+        String currentFieldName;
+
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                currentFieldName = parser.currentName();
+                switch (currentFieldName) {
+                    case ACTIVE_SHARDS:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException(
+                                "failed to parse active shards field, expected number but found unknown type"
+                            );
+                        }
+                        active_shards = parser.intValue();
+                        break;
+                    case INITIALIZING_SHARDS:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException(
+                                "failed to parse initializing shards field, expected number but found unknown type"
+                            );
+                        }
+                        initializing_shards = parser.intValue();
+                        break;
+                    case RELOCATING_SHARDS:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException(
+                                "failed to parse relocating shards field, expected number but found unknown type"
+                            );
+                        }
+                        relocating_shards = parser.intValue();
+                        break;
+                    case UNASSIGNED_SHARDS:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException("failed to parse unassigned field, expected number but found unknown type");
+                        }
+                        unassigned_shards = parser.intValue();
+                        break;
+                    case NODES:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException("failed to parse node field, expected number but found unknown type");
+                        }
+                        nodes = parser.intValue();
+                        break;
+                    case WEIGHTS:
+                        if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                            throw new OpenSearchParseException("failed to parse weight field, expected number but found unknown type");
+                        }
+                        weight = parser.doubleValue();
+                        break;
+                }
+            } else {
+                throw new OpenSearchParseException(
+                    "failed to parse awareness attribute health, expected [{}] but found [{}]",
+                    XContentParser.Token.FIELD_NAME,
+                    token
+                );
+            }
+        }
+        return new ClusterAwarenessAttributeValueHealth(
+            attributeName,
+            active_shards,
+            initializing_shards,
+            relocating_shards,
+            unassigned_shards,
+            nodes,
+            weight
+        );
+    }
+
+    public int getActiveShards() {
+        return activeShards;
+    }
+
+    public void setActiveShards(int activeShards) {
+        this.activeShards = activeShards;
+    }
+
+    public int getUnassignedShards() {
+        return unassignedShards;
+    }
+
+    public void setUnassignedShards(int unassignedShards) {
+        this.unassignedShards = unassignedShards;
+    }
+
+    public int getNodes() {
+        return nodes;
+    }
+
+    public void setNodes(int nodes) {
+        this.nodes = nodes;
+    }
+
+    public double getWeight() {
+        return weight;
+    }
+
+    public void setWeight(double weight) {
+        this.weight = weight;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getInitializingShards() {
+        return initializingShards;
+    }
+
+    public void setInitializingShards(int initializingShards) {
+        this.initializingShards = initializingShards;
+    }
+
+    public int getRelocatingShards() {
+        return relocatingShards;
+    }
+
+    public void setRelocatingShards(int relocatingShards) {
+        this.relocatingShards = relocatingShards;
+    }
+
+    public List<String> getNodeList() {
+        return nodeList;
+    }
+
+    public void setNodeList(List<String> nodeList) {
+        this.nodeList = nodeList;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(name);
+        out.writeVInt(activeShards);
+        out.writeVInt(initializingShards);
+        out.writeVInt(relocatingShards);
+        out.writeVInt(unassignedShards);
+        out.writeVInt(nodes);
+        out.writeDouble(weight);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(getName());
+        builder.field(ACTIVE_SHARDS, getActiveShards());
+        builder.field(INITIALIZING_SHARDS, getInitializingShards());
+        builder.field(RELOCATING_SHARDS, getRelocatingShards());
+        builder.field(UNASSIGNED_SHARDS, getUnassignedShards());
+        builder.field(NODES, getNodes());
+        builder.field(WEIGHTS, getWeight());
+        builder.endObject();
+        return builder;
+    }
+
+    void computeAttributeValueLevelInfo(ClusterState clusterState, boolean displayUnassignedShardLevelInfo, int shardsPerAttributeValue) {
+        // computing nodes info
+        nodes = nodeList.size();
+
+        // computing shards into
+        setShardLevelInfo(clusterState, displayUnassignedShardLevelInfo, shardsPerAttributeValue);
+
+        // compute weight info
+        setWeightInfo(clusterState);
+    }
+
+    private void setShardLevelInfo(ClusterState clusterState, boolean displayUnassignedShardLevelInfo, int shardsPerAttributeValue) {
+
+        for (String nodeId : nodeList) {
+            RoutingNode node = clusterState.getRoutingNodes().node(nodeId);
+            activeShards += node.numberOfShardsWithState(ShardRoutingState.STARTED);
+            relocatingShards += node.numberOfShardsWithState(ShardRoutingState.RELOCATING);
+            initializingShards += node.numberOfShardsWithState(ShardRoutingState.INITIALIZING);
+        }
+
+        // computing unassigned shards info
+        if (displayUnassignedShardLevelInfo) {
+            int unassignedShardsPerAttribute = shardsPerAttributeValue - getActiveShards() - getInitializingShards();
+            setUnassignedShards(unassignedShardsPerAttribute);
+        } else {
+            setUnassignedShards(-1);
+        }
+    }
+
+    private void setWeightInfo(ClusterState clusterState) {
+        WeightedRoutingMetadata weightedRoutingMetadata = clusterState.getMetadata().weightedRoutingMetadata();
+        double attributeWeight = 1.0;
+        if (weightedRoutingMetadata != null) {
+            WeightedRouting weightedRouting = weightedRoutingMetadata.getWeightedRouting();
+            attributeWeight = weightedRouting.weights().getOrDefault(name, 1.0);
+        }
+        setWeight(attributeWeight);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ClusterAwarenessAttributeValueHealth)) return false;
+        ClusterAwarenessAttributeValueHealth that = (ClusterAwarenessAttributeValueHealth) o;
+        return name.equals(that.name)
+            && activeShards == that.activeShards
+            && relocatingShards == that.relocatingShards
+            && initializingShards == that.initializingShards
+            && unassignedShards == that.unassignedShards
+            && nodes == that.nodes
+            && weight == that.weight;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, activeShards, relocatingShards, initializingShards, unassignedShards, nodes, weight);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealth.java b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealth.java
new file mode 100644
index 0000000000000..01d9cfc4438e3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealth.java
@@ -0,0 +1,298 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * Cluster Awareness health information
+ *
+ */
+public class ClusterAwarenessAttributesHealth implements Iterable<ClusterAwarenessAttributeValueHealth>, Writeable, ToXContentFragment {
+
+    private final String awarenessAttributeName;
+    private Map<String, ClusterAwarenessAttributeValueHealth> awarenessAttributeValueHealthMap;
+
+    /**
+     * Creates Awareness AttributeValue Health information
+     *
+     * @param awarenessAttributeValue Awareness Attribute value ie zone, rack etc
+     * @param displayUnassignedShardLevelInfo Governs if unassigned info should be visible or not
+     * @param clusterState cluster state
+     */
+    public ClusterAwarenessAttributesHealth(
+        String awarenessAttributeValue,
+        boolean displayUnassignedShardLevelInfo,
+        ClusterState clusterState
+    ) {
+        awarenessAttributeName = awarenessAttributeValue;
+
+        // This is the Map which is storing the per attribute node list.
+        Map<String, List<String>> attributesNodeList = new HashMap<>();
+
+        // Getting the node map for cluster
+        final Map<String, DiscoveryNode> nodeMap = clusterState.nodes().getDataNodes();
+
+        // This is the map that would store all the stats per attribute ie
+        // health stats for rack-1, rack-2 etc.
+        awarenessAttributeValueHealthMap = new HashMap<>();
+        String attributeValue;
+
+        if (!nodeMap.isEmpty()) {
+            Iterator<String> iter = nodeMap.keySet().iterator();
+            while (iter.hasNext()) {
+                List<String> clusterAwarenessAttributeNodeList;
+                String node = iter.next();
+                DiscoveryNode nodeDiscovery = nodeMap.get(node);
+                Map<String, String> nodeAttributes = nodeDiscovery.getAttributes();
+                if (!nodeAttributes.isEmpty()) {
+                    if (nodeAttributes.containsKey(awarenessAttributeName)) {
+                        attributeValue = nodeAttributes.get(awarenessAttributeName);
+
+                        if (!attributesNodeList.containsKey(attributeValue)) {
+                            clusterAwarenessAttributeNodeList = new ArrayList<>();
+                            attributesNodeList.put(attributeValue, clusterAwarenessAttributeNodeList);
+                        } else {
+                            clusterAwarenessAttributeNodeList = attributesNodeList.get(attributeValue);
+                        }
+                        clusterAwarenessAttributeNodeList.add(node);
+                    }
+                }
+            }
+        }
+
+        setClusterAwarenessAttributeValue(attributesNodeList, displayUnassignedShardLevelInfo, clusterState);
+    }
+
+    private void setClusterAwarenessAttributeValue(
+        Map<String, List<String>> perAttributeValueNodeList,
+        boolean displayUnassignedShardLevelInfo,
+        ClusterState clusterState
+    ) {
+        int numAttributes = perAttributeValueNodeList.size();
+        int shardsPerAttributeValue = 0;
+
+        // Can happen customer has defined weights as well as awareness attribute but no node level attribute was there
+        // So to avoid divide-by-zero error checking this
+        if (numAttributes != 0) {
+            shardsPerAttributeValue = clusterState.getMetadata().getTotalNumberOfShards() / numAttributes;
+        }
+
+        Map<String, ClusterAwarenessAttributeValueHealth> clusterAwarenessAttributeValueHealthMap = new HashMap<>();
+
+        for (String attributeValueKey : perAttributeValueNodeList.keySet()) {
+            ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth = new ClusterAwarenessAttributeValueHealth(
+                attributeValueKey,
+                perAttributeValueNodeList.get(attributeValueKey)
+            );
+            // computing attribute info
+            clusterAwarenessAttributeValueHealth.computeAttributeValueLevelInfo(
+                clusterState,
+                displayUnassignedShardLevelInfo,
+                shardsPerAttributeValue
+            );
+            clusterAwarenessAttributeValueHealthMap.put(attributeValueKey, clusterAwarenessAttributeValueHealth);
+        }
+        awarenessAttributeValueHealthMap = clusterAwarenessAttributeValueHealthMap;
+    }
+
+    public ClusterAwarenessAttributesHealth(final StreamInput in) throws IOException {
+        awarenessAttributeName = in.readString();
+        int size = in.readVInt();
+        if (size > 0) {
+            awarenessAttributeValueHealthMap = new HashMap<>(size);
+            for (int i = 0; i < size; i++) {
+                ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth = new ClusterAwarenessAttributeValueHealth(in);
+                awarenessAttributeValueHealthMap.put(clusterAwarenessAttributeValueHealth.getName(), clusterAwarenessAttributeValueHealth);
+            }
+        } else {
+            awarenessAttributeValueHealthMap = Collections.emptyMap();
+        }
+    }
+
+    ClusterAwarenessAttributesHealth(
+        String awarenessAttributeName,
+        Map<String, ClusterAwarenessAttributeValueHealth> awarenessAttributeValueHealthMap
+    ) {
+        this.awarenessAttributeName = awarenessAttributeName;
+        this.awarenessAttributeValueHealthMap = awarenessAttributeValueHealthMap;
+    }
+
+    public String getAwarenessAttributeName() {
+        return awarenessAttributeName;
+    }
+
+    public Map<String, ClusterAwarenessAttributeValueHealth> getAwarenessAttributeHealthMap() {
+        return awarenessAttributeValueHealthMap;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(awarenessAttributeName);
+        int size = awarenessAttributeValueHealthMap.size();
+        out.writeVInt(size);
+        if (size > 0) {
+            for (ClusterAwarenessAttributeValueHealth attributeHealthMapPerValue : this) {
+                attributeHealthMapPerValue.writeTo(out);
+            }
+        }
+    }
+
+    @Override
+    public Iterator<ClusterAwarenessAttributeValueHealth> iterator() {
+        return awarenessAttributeValueHealthMap.values().iterator();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(getAwarenessAttributeName());
+        for (ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth : this) {
+            clusterAwarenessAttributeValueHealth.toXContent(builder, params);
+        }
+        builder.endObject();
+        return null;
+    }
+
+    public static ClusterAwarenessAttributesHealth fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        XContentParser.Token token = parser.nextToken();
+        ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
+        String attributeName = parser.currentName();
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+        Map<String, ClusterAwarenessAttributeValueHealth> clusterAwarenessAttributeValueHealthMap = new HashMap<>();
+        String currentFieldName;
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
+            String attributeValue = parser.currentName();
+            token = parser.nextToken();
+            if (token == XContentParser.Token.START_OBJECT) {
+                int active_shards = 0;
+                int initializing_shards = 0;
+                int relocating_shards = 0;
+                int unassigned_shards = 0;
+                int nodes = 0;
+                double weight = 0.0;
+                while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                    if (token == XContentParser.Token.FIELD_NAME) {
+                        currentFieldName = parser.currentName();
+                        switch (currentFieldName) {
+                            case "active_shards":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse active shards field, expected number but found unknown type"
+                                    );
+                                }
+                                active_shards = parser.intValue();
+                                break;
+                            case "initializing_shards":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse initializing shards field, expected number but found unknown type"
+                                    );
+                                }
+                                initializing_shards = parser.intValue();
+                                break;
+                            case "relocating_shards":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse relocating shards field, expected number but found unknown type"
+                                    );
+                                }
+                                relocating_shards = parser.intValue();
+                                break;
+                            case "unassigned_shards":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse unassigned field, expected number but found unknown type"
+                                    );
+                                }
+                                unassigned_shards = parser.intValue();
+                                break;
+                            case "data_nodes":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse node field, expected number but found unknown type"
+                                    );
+                                }
+                                nodes = parser.intValue();
+                                break;
+                            case "weight":
+                                if (parser.nextToken() != XContentParser.Token.VALUE_NUMBER) {
+                                    throw new OpenSearchParseException(
+                                        "failed to parse weight field, expected number but found unknown type"
+                                    );
+                                }
+                                weight = parser.doubleValue();
+                                break;
+                        }
+                    } else {
+                        throw new OpenSearchParseException("failed to parse attribute health map");
+                    }
+                }
+                ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth = new ClusterAwarenessAttributeValueHealth(
+                    attributeValue,
+                    active_shards,
+                    initializing_shards,
+                    relocating_shards,
+                    unassigned_shards,
+                    nodes,
+                    weight
+                );
+                clusterAwarenessAttributeValueHealthMap.put(
+                    clusterAwarenessAttributeValueHealth.getName(),
+                    clusterAwarenessAttributeValueHealth
+                );
+            } else {
+                throw new OpenSearchParseException("failed to parse awareness attribute value health");
+            }
+        }
+        ensureExpectedToken(XContentParser.Token.END_OBJECT, parser.nextToken(), parser);
+        return new ClusterAwarenessAttributesHealth(attributeName, clusterAwarenessAttributeValueHealthMap);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ClusterAwarenessAttributesHealth)) return false;
+        ClusterAwarenessAttributesHealth that = (ClusterAwarenessAttributesHealth) o;
+        return awarenessAttributeName.equals(that.awarenessAttributeName)
+            && awarenessAttributeValueHealthMap.size() == that.awarenessAttributeValueHealthMap.size();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(awarenessAttributeName, awarenessAttributeValueHealthMap);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealth.java b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealth.java
new file mode 100644
index 0000000000000..1643db5a1f460
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealth.java
@@ -0,0 +1,161 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Cluster state Awareness health information
+ */
+public class ClusterAwarenessHealth implements Writeable, ToXContentFragment, Iterable<ClusterAwarenessAttributesHealth> {
+
+    private static final String AWARENESS_ATTRIBUTE = "awareness_attributes";
+    private final Map<String, ClusterAwarenessAttributesHealth> clusterAwarenessAttributesHealthMap;
+
+    /**
+     * Creates cluster awareness health from cluster state.
+     *
+     * @param clusterState           The current cluster state. Must not be null.
+     * @param clusterSettings        the current cluster settings.
+     * @param awarenessAttributeName Name of awareness attribute for which we need to see the health
+     */
+    public ClusterAwarenessHealth(ClusterState clusterState, ClusterSettings clusterSettings, String awarenessAttributeName) {
+        // This property will govern if we need to show unassigned shard info or not
+        boolean displayUnassignedShardLevelInfo;
+        ClusterAwarenessAttributesHealth clusterAwarenessAttributesHealth;
+        clusterAwarenessAttributesHealthMap = new HashMap<>();
+        List<String> awarenessAttributeList = getAwarenessAttributeList(awarenessAttributeName, clusterSettings);
+        for (String awarenessAttribute : awarenessAttributeList) {
+            displayUnassignedShardLevelInfo = canCalcUnassignedShards(clusterSettings, awarenessAttribute);
+            clusterAwarenessAttributesHealth = new ClusterAwarenessAttributesHealth(
+                awarenessAttribute,
+                displayUnassignedShardLevelInfo,
+                clusterState
+            );
+            clusterAwarenessAttributesHealthMap.put(awarenessAttribute, clusterAwarenessAttributesHealth);
+        }
+    }
+
+    public ClusterAwarenessHealth(final StreamInput in) throws IOException {
+        int size = in.readVInt();
+        if (size > 0) {
+            clusterAwarenessAttributesHealthMap = new HashMap<>(size);
+            for (int i = 0; i < size; i++) {
+                ClusterAwarenessAttributesHealth clusterAwarenessAttributesHealth = new ClusterAwarenessAttributesHealth(in);
+                clusterAwarenessAttributesHealthMap.put(
+                    clusterAwarenessAttributesHealth.getAwarenessAttributeName(),
+                    clusterAwarenessAttributesHealth
+                );
+            }
+        } else {
+            clusterAwarenessAttributesHealthMap = Collections.emptyMap();
+        }
+    }
+
+    private List<String> getAwarenessAttributeList(String awarenessAttributeName, ClusterSettings clusterSettings) {
+        // Helper function to check if we need health for all or for one awareness attribute.
+        boolean displayAllAwarenessAttribute = awarenessAttributeName == null || awarenessAttributeName.isBlank();
+        List<String> awarenessAttributeList = new ArrayList<>();
+        if (!displayAllAwarenessAttribute) {
+            awarenessAttributeList.add(awarenessAttributeName);
+        } else {
+            awarenessAttributeList = clusterSettings.get(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING);
+        }
+        return awarenessAttributeList;
+    }
+
+    private boolean canCalcUnassignedShards(ClusterSettings clusterSettings, String awarenessAttributeName) {
+        // Getting the replicaEnforcement settings as both are necessary for replica enforcement.
+        boolean allocationAwarenessBalance = clusterSettings.get(
+            AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING
+        );
+        Settings forcedAwarenessSettings = clusterSettings.get(
+            AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING
+        );
+
+        boolean forcedZoneSettingsExists = false;
+
+        if (!forcedAwarenessSettings.isEmpty()) {
+            // We will only mark true if particular awareness attribute exists
+            if (forcedAwarenessSettings.hasValue(awarenessAttributeName + ".values")) {
+                forcedZoneSettingsExists = true;
+            }
+        }
+        return allocationAwarenessBalance && forcedZoneSettingsExists;
+    }
+
+    public Map<String, ClusterAwarenessAttributesHealth> getClusterAwarenessAttributesHealthMap() {
+        return clusterAwarenessAttributesHealthMap;
+    }
+
+    @Override
+    public void writeTo(final StreamOutput out) throws IOException {
+        int size = clusterAwarenessAttributesHealthMap.size();
+        out.writeVInt(size);
+        if (size > 0) {
+            for (ClusterAwarenessAttributesHealth awarenessAttributeValueHealth : this) {
+                awarenessAttributeValueHealth.writeTo(out);
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "ClusterAwarenessHealth{"
+            + "clusterAwarenessHealth.clusterAwarenessAttributesHealthMap.size="
+            + (clusterAwarenessAttributesHealthMap == null ? "null" : clusterAwarenessAttributesHealthMap.size())
+            + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ClusterAwarenessHealth that = (ClusterAwarenessHealth) o;
+        return clusterAwarenessAttributesHealthMap.size() == that.clusterAwarenessAttributesHealthMap.size();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(clusterAwarenessAttributesHealthMap);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(AWARENESS_ATTRIBUTE);
+        for (ClusterAwarenessAttributesHealth awarenessAttributeValueHealth : this) {
+            awarenessAttributeValueHealth.toXContent(builder, params);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public Iterator<ClusterAwarenessAttributesHealth> iterator() {
+        return clusterAwarenessAttributesHealthMap.values().iterator();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/awarenesshealth/package-info.java b/server/src/main/java/org/opensearch/cluster/awarenesshealth/package-info.java
new file mode 100644
index 0000000000000..6448d484eeac5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/awarenesshealth/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster HA Health Foundation classes. */
+package org.opensearch.cluster.awarenesshealth;
diff --git a/server/src/main/java/org/opensearch/cluster/block/ClusterBlock.java b/server/src/main/java/org/opensearch/cluster/block/ClusterBlock.java
index 9da2bdeaabd8e..40a5080ba74e7 100644
--- a/server/src/main/java/org/opensearch/cluster/block/ClusterBlock.java
+++ b/server/src/main/java/org/opensearch/cluster/block/ClusterBlock.java
@@ -33,18 +33,23 @@
 package org.opensearch.cluster.block;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.EnumSet;
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * Blocks the cluster for concurrency
+ *
+ * @opensearch.internal
+ */
 public class ClusterBlock implements Writeable, ToXContentFragment {
 
     private final int id;
diff --git a/server/src/main/java/org/opensearch/cluster/block/ClusterBlockException.java b/server/src/main/java/org/opensearch/cluster/block/ClusterBlockException.java
index 8a6401b985b90..4673f075e8439 100644
--- a/server/src/main/java/org/opensearch/cluster/block/ClusterBlockException.java
+++ b/server/src/main/java/org/opensearch/cluster/block/ClusterBlockException.java
@@ -33,9 +33,9 @@
 package org.opensearch.cluster.block;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -46,6 +46,11 @@
 
 import static java.util.Collections.unmodifiableSet;
 
+/**
+ * Internal exception on obtaining a cluster block
+ *
+ * @opensearch.internal
+ */
 public class ClusterBlockException extends OpenSearchException {
     private final Set<ClusterBlock> blocks;
 
diff --git a/server/src/main/java/org/opensearch/cluster/block/ClusterBlockLevel.java b/server/src/main/java/org/opensearch/cluster/block/ClusterBlockLevel.java
index fa8f7f19b752a..5ec847e100c86 100644
--- a/server/src/main/java/org/opensearch/cluster/block/ClusterBlockLevel.java
+++ b/server/src/main/java/org/opensearch/cluster/block/ClusterBlockLevel.java
@@ -34,11 +34,17 @@
 
 import java.util.EnumSet;
 
+/**
+ * What level to block the cluster
+ *
+ * @opensearch.internal
+ */
 public enum ClusterBlockLevel {
     READ,
     WRITE,
     METADATA_READ,
-    METADATA_WRITE;
+    METADATA_WRITE,
+    CREATE_INDEX;
 
     public static final EnumSet<ClusterBlockLevel> ALL = EnumSet.allOf(ClusterBlockLevel.class);
     public static final EnumSet<ClusterBlockLevel> READ_WRITE = EnumSet.of(READ, WRITE);
diff --git a/server/src/main/java/org/opensearch/cluster/block/ClusterBlocks.java b/server/src/main/java/org/opensearch/cluster/block/ClusterBlocks.java
index a9bde418e962c..bcb4f7f71268e 100644
--- a/server/src/main/java/org/opensearch/cluster/block/ClusterBlocks.java
+++ b/server/src/main/java/org/opensearch/cluster/block/ClusterBlocks.java
@@ -32,17 +32,16 @@
 
 package org.opensearch.cluster.block;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.index.IndexModule;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -59,19 +58,21 @@
 
 /**
  * Represents current cluster level blocks to block dirty operations done against the cluster.
+ *
+ * @opensearch.internal
  */
 public class ClusterBlocks extends AbstractDiffable<ClusterBlocks> {
-    public static final ClusterBlocks EMPTY_CLUSTER_BLOCK = new ClusterBlocks(emptySet(), ImmutableOpenMap.of());
+    public static final ClusterBlocks EMPTY_CLUSTER_BLOCK = new ClusterBlocks(emptySet(), Map.of());
 
     private final Set<ClusterBlock> global;
 
-    private final ImmutableOpenMap<String, Set<ClusterBlock>> indicesBlocks;
+    private final Map<String, Set<ClusterBlock>> indicesBlocks;
 
     private final EnumMap<ClusterBlockLevel, ImmutableLevelHolder> levelHolders;
 
-    ClusterBlocks(Set<ClusterBlock> global, ImmutableOpenMap<String, Set<ClusterBlock>> indicesBlocks) {
+    ClusterBlocks(Set<ClusterBlock> global, final Map<String, Set<ClusterBlock>> indicesBlocks) {
         this.global = global;
-        this.indicesBlocks = indicesBlocks;
+        this.indicesBlocks = Collections.unmodifiableMap(indicesBlocks);
         levelHolders = generateLevelHolders(global, indicesBlocks);
     }
 
@@ -79,7 +80,7 @@ public Set<ClusterBlock> global() {
         return global;
     }
 
-    public ImmutableOpenMap<String, Set<ClusterBlock>> indices() {
+    public Map<String, Set<ClusterBlock>> indices() {
         return indicesBlocks;
     }
 
@@ -87,7 +88,7 @@ public Set<ClusterBlock> global(ClusterBlockLevel level) {
         return levelHolders.get(level).global();
     }
 
-    public ImmutableOpenMap<String, Set<ClusterBlock>> indices(ClusterBlockLevel level) {
+    public Map<String, Set<ClusterBlock>> indices(ClusterBlockLevel level) {
         return levelHolders.get(level).indices();
     }
 
@@ -97,7 +98,7 @@ private Set<ClusterBlock> blocksForIndex(ClusterBlockLevel level, String index)
 
     private static EnumMap<ClusterBlockLevel, ImmutableLevelHolder> generateLevelHolders(
         Set<ClusterBlock> global,
-        ImmutableOpenMap<String, Set<ClusterBlock>> indicesBlocks
+        final Map<String, Set<ClusterBlock>> indicesBlocks
     ) {
 
         EnumMap<ClusterBlockLevel, ImmutableLevelHolder> levelHolders = new EnumMap<>(ClusterBlockLevel.class);
@@ -105,11 +106,11 @@ private static EnumMap<ClusterBlockLevel, ImmutableLevelHolder> generateLevelHol
             Predicate<ClusterBlock> containsLevel = block -> block.contains(level);
             Set<ClusterBlock> newGlobal = unmodifiableSet(global.stream().filter(containsLevel).collect(toSet()));
 
-            ImmutableOpenMap.Builder<String, Set<ClusterBlock>> indicesBuilder = ImmutableOpenMap.builder();
-            for (ObjectObjectCursor<String, Set<ClusterBlock>> entry : indicesBlocks) {
-                indicesBuilder.put(entry.key, unmodifiableSet(entry.value.stream().filter(containsLevel).collect(toSet())));
+            final Map<String, Set<ClusterBlock>> indicesBuilder = new HashMap<>();
+            for (final Map.Entry<String, Set<ClusterBlock>> entry : indicesBlocks.entrySet()) {
+                indicesBuilder.put(entry.getKey(), unmodifiableSet(entry.getValue().stream().filter(containsLevel).collect(toSet())));
             }
-            levelHolders.put(level, new ImmutableLevelHolder(newGlobal, indicesBuilder.build()));
+            levelHolders.put(level, new ImmutableLevelHolder(newGlobal, indicesBuilder));
         }
         return levelHolders;
     }
@@ -202,6 +203,13 @@ public ClusterBlockException globalBlockedException(ClusterBlockLevel level) {
         return new ClusterBlockException(global(level));
     }
 
+    public IndexCreateBlockException createIndexBlockedException(ClusterBlockLevel level) {
+        if (!globalBlocked(level)) {
+            return null;
+        }
+        return new IndexCreateBlockException(global(level));
+    }
+
     public void indexBlockedRaiseException(ClusterBlockLevel level, String index) throws ClusterBlockException {
         ClusterBlockException blockException = indexBlockedException(level, index);
         if (blockException != null) {
@@ -278,9 +286,9 @@ public String toString() {
                 sb.append("      ").append(block);
             }
         }
-        for (ObjectObjectCursor<String, Set<ClusterBlock>> entry : indices()) {
-            sb.append("   ").append(entry.key).append(":\n");
-            for (ClusterBlock block : entry.value) {
+        for (final Map.Entry<String, Set<ClusterBlock>> entry : indices().entrySet()) {
+            sb.append("   ").append(entry.getKey()).append(":\n");
+            for (ClusterBlock block : entry.getValue()) {
                 sb.append("      ").append(block);
             }
         }
@@ -300,10 +308,7 @@ private static void writeBlockSet(Set<ClusterBlock> blocks, StreamOutput out) th
 
     public static ClusterBlocks readFrom(StreamInput in) throws IOException {
         final Set<ClusterBlock> global = readBlockSet(in);
-        ImmutableOpenMap<String, Set<ClusterBlock>> indicesBlocks = in.readImmutableMap(
-            i -> i.readString().intern(),
-            ClusterBlocks::readBlockSet
-        );
+        final Map<String, Set<ClusterBlock>> indicesBlocks = in.readMap(i -> i.readString().intern(), ClusterBlocks::readBlockSet);
         if (global.isEmpty() && indicesBlocks.isEmpty()) {
             return EMPTY_CLUSTER_BLOCK;
         }
@@ -319,21 +324,26 @@ public static Diff<ClusterBlocks> readDiffFrom(StreamInput in) throws IOExceptio
         return AbstractDiffable.readDiffFrom(ClusterBlocks::readFrom, in);
     }
 
+    /**
+     * An immutable level holder.
+     *
+     * @opensearch.internal
+     */
     static class ImmutableLevelHolder {
 
         private final Set<ClusterBlock> global;
-        private final ImmutableOpenMap<String, Set<ClusterBlock>> indices;
+        private final Map<String, Set<ClusterBlock>> indices;
 
-        ImmutableLevelHolder(Set<ClusterBlock> global, ImmutableOpenMap<String, Set<ClusterBlock>> indices) {
+        ImmutableLevelHolder(Set<ClusterBlock> global, final Map<String, Set<ClusterBlock>> indices) {
             this.global = global;
-            this.indices = indices;
+            this.indices = Collections.unmodifiableMap(indices);
         }
 
         public Set<ClusterBlock> global() {
             return global;
         }
 
-        public ImmutableOpenMap<String, Set<ClusterBlock>> indices() {
+        public Map<String, Set<ClusterBlock>> indices() {
             return indices;
         }
     }
@@ -342,6 +352,11 @@ public static Builder builder() {
         return new Builder();
     }
 
+    /**
+     * Builder for cluster blocks.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final Set<ClusterBlock> global = new HashSet<>();
@@ -352,11 +367,11 @@ public Builder() {}
 
         public Builder blocks(ClusterBlocks blocks) {
             global.addAll(blocks.global());
-            for (ObjectObjectCursor<String, Set<ClusterBlock>> entry : blocks.indices()) {
-                if (!indices.containsKey(entry.key)) {
-                    indices.put(entry.key, new HashSet<>());
+            for (final Map.Entry<String, Set<ClusterBlock>> entry : blocks.indices().entrySet()) {
+                if (!indices.containsKey(entry.getKey())) {
+                    indices.put(entry.getKey(), new HashSet<>());
                 }
-                indices.get(entry.key).addAll(entry.value);
+                indices.get(entry.getKey()).addAll(entry.getValue());
             }
             return this;
         }
@@ -381,6 +396,9 @@ public Builder addBlocks(IndexMetadata indexMetadata) {
             if (IndexMetadata.INDEX_BLOCKS_READ_ONLY_ALLOW_DELETE_SETTING.get(indexMetadata.getSettings())) {
                 addIndexBlock(indexName, IndexMetadata.INDEX_READ_ONLY_ALLOW_DELETE_BLOCK);
             }
+            if (IndexModule.Type.REMOTE_SNAPSHOT.match(indexMetadata.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey()))) {
+                addIndexBlock(indexName, IndexMetadata.REMOTE_READ_ONLY_ALLOW_DELETE);
+            }
             return this;
         }
 
@@ -453,11 +471,11 @@ public ClusterBlocks build() {
                 return EMPTY_CLUSTER_BLOCK;
             }
             // We copy the block sets here in case of the builder is modified after build is called
-            ImmutableOpenMap.Builder<String, Set<ClusterBlock>> indicesBuilder = ImmutableOpenMap.builder(indices.size());
+            final HashMap<String, Set<ClusterBlock>> indicesBuilder = new HashMap<>(indices.size());
             for (Map.Entry<String, Set<ClusterBlock>> entry : indices.entrySet()) {
                 indicesBuilder.put(entry.getKey(), unmodifiableSet(new HashSet<>(entry.getValue())));
             }
-            return new ClusterBlocks(unmodifiableSet(new HashSet<>(global)), indicesBuilder.build());
+            return new ClusterBlocks(unmodifiableSet(new HashSet<>(global)), indicesBuilder);
         }
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/block/IndexCreateBlockException.java b/server/src/main/java/org/opensearch/cluster/block/IndexCreateBlockException.java
new file mode 100644
index 0000000000000..729d76c72e99e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/block/IndexCreateBlockException.java
@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.block;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+
+import java.io.IOException;
+import java.util.Set;
+
+/**
+ * Internal exception on obtaining an index create block
+ *
+ * @opensearch.internal
+ */
+public class IndexCreateBlockException extends ClusterBlockException {
+
+    public IndexCreateBlockException(Set<ClusterBlock> globalLevelBlocks) {
+        super(globalLevelBlocks);
+    }
+
+    public IndexCreateBlockException(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/block/package-info.java b/server/src/main/java/org/opensearch/cluster/block/package-info.java
new file mode 100644
index 0000000000000..a51b4623d34af
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/block/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Block level classes. */
+package org.opensearch.cluster.block;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ApplyCommitRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/ApplyCommitRequest.java
index 40d6375d8d916..a722ccd5c6aff 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ApplyCommitRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ApplyCommitRequest.java
@@ -32,15 +32,17 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
- * A master node sends this request to its peers to inform them that it could commit the
+ * A cluster-manager node sends this request to its peers to inform them that it could commit the
  * cluster state with the given term and version. Peers that have accepted the given cluster
  * state will then consider it as committed and proceed to apply the state locally.
+ *
+ * @opensearch.internal
  */
 public class ApplyCommitRequest extends TermVersionRequest {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java b/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java
index ce34a21e4adb6..addd2b3e46597 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java
@@ -69,6 +69,11 @@
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 
+/**
+ * Service for bootstrapping the OpenSearch cluster
+ *
+ * @opensearch.internal
+ */
 public class ClusterBootstrapService {
 
     public static final Setting<List<String>> INITIAL_MASTER_NODES_SETTING = Setting.listSetting(
@@ -113,12 +118,12 @@ public ClusterBootstrapService(
         BooleanSupplier isBootstrappedSupplier,
         Consumer<VotingConfiguration> votingConfigurationConsumer
     ) {
+        // TODO: Remove variable 'initialClusterManagerSettingName' after removing MASTER_ROLE.
+        String initialClusterManagerSettingName = INITIAL_CLUSTER_MANAGER_NODES_SETTING.exists(settings)
+            ? INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey()
+            : INITIAL_MASTER_NODES_SETTING.getKey();
         if (DiscoveryModule.isSingleNodeDiscovery(settings)) {
             if (INITIAL_CLUSTER_MANAGER_NODES_SETTING.existsOrFallbackExists(settings)) {
-                // TODO: Remove variable 'initialClusterManagerSettingName' after removing MASTER_ROLE.
-                String initialClusterManagerSettingName = INITIAL_CLUSTER_MANAGER_NODES_SETTING.exists(settings)
-                    ? INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey()
-                    : INITIAL_MASTER_NODES_SETTING.getKey();
                 throw new IllegalArgumentException(
                     "setting ["
                         + initialClusterManagerSettingName
@@ -129,23 +134,23 @@ public ClusterBootstrapService(
                         + "]"
                 );
             }
-            if (DiscoveryNode.isMasterNode(settings) == false) {
+            if (DiscoveryNode.isClusterManagerNode(settings) == false) {
                 throw new IllegalArgumentException(
                     "node with ["
                         + DiscoveryModule.DISCOVERY_TYPE_SETTING.getKey()
                         + "] set to ["
                         + DiscoveryModule.SINGLE_NODE_DISCOVERY_TYPE
-                        + "] must be master-eligible"
+                        + "] must be cluster-manager-eligible"
                 );
             }
             bootstrapRequirements = Collections.singleton(Node.NODE_NAME_SETTING.get(settings));
             unconfiguredBootstrapTimeout = null;
         } else {
-            final List<String> initialMasterNodes = INITIAL_CLUSTER_MANAGER_NODES_SETTING.get(settings);
-            bootstrapRequirements = unmodifiableSet(new LinkedHashSet<>(initialMasterNodes));
-            if (bootstrapRequirements.size() != initialMasterNodes.size()) {
+            final List<String> initialClusterManagerNodes = INITIAL_CLUSTER_MANAGER_NODES_SETTING.get(settings);
+            bootstrapRequirements = unmodifiableSet(new LinkedHashSet<>(initialClusterManagerNodes));
+            if (bootstrapRequirements.size() != initialClusterManagerNodes.size()) {
                 throw new IllegalArgumentException(
-                    "setting [" + INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey() + "] contains duplicates: " + initialMasterNodes
+                    "setting [" + initialClusterManagerSettingName + "] contains duplicates: " + initialClusterManagerNodes
                 );
             }
             unconfiguredBootstrapTimeout = discoveryIsConfigured(settings) ? null : UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING.get(settings);
@@ -163,14 +168,15 @@ public static boolean discoveryIsConfigured(Settings settings) {
             LEGACY_DISCOVERY_HOSTS_PROVIDER_SETTING,
             DISCOVERY_SEED_HOSTS_SETTING,
             LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING,
-            INITIAL_CLUSTER_MANAGER_NODES_SETTING
+            INITIAL_CLUSTER_MANAGER_NODES_SETTING,
+            INITIAL_MASTER_NODES_SETTING
         ).anyMatch(s -> s.exists(settings));
     }
 
     void onFoundPeersUpdated() {
         final Set<DiscoveryNode> nodes = getDiscoveredNodes();
         if (bootstrappingPermitted.get()
-            && transportService.getLocalNode().isMasterNode()
+            && transportService.getLocalNode().isClusterManagerNode()
             && bootstrapRequirements.isEmpty() == false
             && isBootstrappedSupplier.getAsBoolean() == false
             && nodes.stream().noneMatch(Coordinator::isZen1Node)) {
@@ -213,13 +219,13 @@ void scheduleUnconfiguredBootstrap() {
             return;
         }
 
-        if (transportService.getLocalNode().isMasterNode() == false) {
+        if (transportService.getLocalNode().isClusterManagerNode() == false) {
             return;
         }
 
         logger.info(
             "no discovery configuration found, will perform best-effort cluster bootstrapping after [{}] "
-                + "unless existing master is discovered",
+                + "unless existing cluster-manager is discovered",
             unconfiguredBootstrapTimeout
         );
 
@@ -251,7 +257,7 @@ private Set<DiscoveryNode> getDiscoveredNodes() {
     }
 
     private void startBootstrap(Set<DiscoveryNode> discoveryNodes, List<String> unsatisfiedRequirements) {
-        assert discoveryNodes.stream().allMatch(DiscoveryNode::isMasterNode) : discoveryNodes;
+        assert discoveryNodes.stream().allMatch(DiscoveryNode::isClusterManagerNode) : discoveryNodes;
         assert discoveryNodes.stream().noneMatch(Coordinator::isZen1Node) : discoveryNodes;
         assert unsatisfiedRequirements.size() < discoveryNodes.size() : discoveryNodes + " smaller than " + unsatisfiedRequirements;
         if (bootstrappingPermitted.compareAndSet(true, false)) {
@@ -271,7 +277,7 @@ public static boolean isBootstrapPlaceholder(String nodeId) {
     }
 
     private void doBootstrap(VotingConfiguration votingConfiguration) {
-        assert transportService.getLocalNode().isMasterNode();
+        assert transportService.getLocalNode().isClusterManagerNode();
 
         try {
             votingConfigurationConsumer.accept(votingConfiguration);
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelper.java b/server/src/main/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelper.java
index c36a2983a011a..4a301e4395140 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelper.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelper.java
@@ -40,9 +40,9 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.threadpool.ThreadPool;
@@ -59,6 +59,11 @@
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Helper for cluster failure events
+ *
+ * @opensearch.internal
+ */
 public class ClusterFormationFailureHelper {
     private static final Logger logger = LogManager.getLogger(ClusterFormationFailureHelper.class);
 
@@ -102,6 +107,11 @@ public void stop() {
         warningScheduler = null;
     }
 
+    /**
+     * A warning scheduler.
+     *
+     * @opensearch.internal
+     */
     private class WarningScheduler {
 
         private boolean isActive() {
@@ -138,6 +148,11 @@ public String toString() {
         }
     }
 
+    /**
+     * State of the cluster formation.
+     *
+     * @opensearch.internal
+     */
     static class ClusterFormationState {
         private final Settings settings;
         private final ClusterState clusterState;
@@ -169,9 +184,10 @@ String getDescription() {
             if (statusInfo.getStatus() == UNHEALTHY) {
                 return String.format(Locale.ROOT, "this node is unhealthy: %s", statusInfo.getInfo());
             }
-            final List<String> clusterStateNodes = StreamSupport.stream(clusterState.nodes().getMasterNodes().values().spliterator(), false)
-                .map(n -> n.value.toString())
-                .collect(Collectors.toList());
+            final List<String> clusterStateNodes = StreamSupport.stream(
+                clusterState.nodes().getClusterManagerNodes().values().spliterator(),
+                false
+            ).map(n -> n.toString()).collect(Collectors.toList());
 
             final String discoveryWillContinueDescription = String.format(
                 Locale.ROOT,
@@ -191,8 +207,8 @@ String getDescription() {
                 discoveryWillContinueDescription
             );
 
-            if (clusterState.nodes().getLocalNode().isMasterNode() == false) {
-                return String.format(Locale.ROOT, "master not discovered yet: %s", discoveryStateIgnoringQuorum);
+            if (clusterState.nodes().getLocalNode().isClusterManagerNode() == false) {
+                return String.format(Locale.ROOT, "cluster-manager not discovered yet: %s", discoveryStateIgnoringQuorum);
             }
 
             if (clusterState.getLastAcceptedConfiguration().isEmpty()) {
@@ -203,14 +219,14 @@ String getDescription() {
                 } else {
                     bootstrappingDescription = String.format(
                         Locale.ROOT,
-                        "this node must discover master-eligible nodes %s to bootstrap a cluster",
+                        "this node must discover cluster-manager-eligible nodes %s to bootstrap a cluster",
                         INITIAL_CLUSTER_MANAGER_NODES_SETTING.get(settings)
                     );
                 }
 
                 return String.format(
                     Locale.ROOT,
-                    "master not discovered yet, this node has not previously joined a bootstrapped cluster, and %s: %s",
+                    "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and %s: %s",
                     bootstrappingDescription,
                     discoveryStateIgnoringQuorum
                 );
@@ -218,10 +234,11 @@ String getDescription() {
 
             assert clusterState.getLastCommittedConfiguration().isEmpty() == false;
 
-            if (clusterState.getLastCommittedConfiguration().equals(VotingConfiguration.MUST_JOIN_ELECTED_MASTER)) {
+            if (clusterState.getLastCommittedConfiguration().equals(VotingConfiguration.MUST_JOIN_ELECTED_MASTER)
+                || clusterState.getLastCommittedConfiguration().equals(VotingConfiguration.MUST_JOIN_ELECTED_CLUSTER_MANAGER)) {
                 return String.format(
                     Locale.ROOT,
-                    "master not discovered yet and this node was detached from its previous cluster, have discovered %s; %s",
+                    "cluster-manager not discovered yet and this node was detached from its previous cluster, have discovered %s; %s",
                     foundPeers,
                     discoveryWillContinueDescription
                 );
@@ -250,7 +267,7 @@ String getDescription() {
 
             return String.format(
                 Locale.ROOT,
-                "master not discovered or elected yet, an election requires %s, have discovered %s which %s; %s",
+                "cluster-manager not discovered or elected yet, an election requires %s, have discovered %s which %s; %s",
                 quorumDescription,
                 foundPeers,
                 isQuorumOrNot,
@@ -269,8 +286,8 @@ private String describeQuorum(VotingConfiguration votingConfiguration) {
 
             if (nodeIds.size() == 1) {
                 if (nodeIds.contains(GatewayMetaState.STALE_STATE_CONFIG_NODE_ID)) {
-                    return "one or more nodes that have already participated as master-eligible nodes in the cluster but this node was "
-                        + "not master-eligible the last time it joined the cluster";
+                    return "one or more nodes that have already participated as cluster-manager-eligible nodes in the cluster but this node was "
+                        + "not cluster-manager-eligible the last time it joined the cluster";
                 } else {
                     return "a node with id " + realNodeIds;
                 }
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ClusterStatePublisher.java b/server/src/main/java/org/opensearch/cluster/coordination/ClusterStatePublisher.java
index 47a18d5be1ec4..39d05e672f977 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ClusterStatePublisher.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ClusterStatePublisher.java
@@ -31,16 +31,21 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 
+/**
+ * Publishes the cluster state
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStatePublisher {
     /**
-     * Publish all the changes to the cluster from the master (can be called just by the master). The publish
-     * process should apply this state to the master as well!
+     * Publish all the changes to the cluster from the cluster-manager (can be called just by the cluster-manager). The publish
+     * process should apply this state to the cluster-manager as well!
      *
      * The publishListener allows to wait for the publication to complete, which can be either successful completion, timing out or failing.
      * The method is guaranteed to pass back a {@link FailedToCommitClusterStateException} to the publishListener if the change is not
@@ -51,6 +56,11 @@ public interface ClusterStatePublisher {
      */
     void publish(ClusterChangedEvent clusterChangedEvent, ActionListener<Void> publishListener, AckListener ackListener);
 
+    /**
+     * An acknowledgement listener.
+     *
+     * @opensearch.internal
+     */
     interface AckListener {
         /**
          * Should be called when the cluster coordination layer has committed the cluster state (i.e. even if this publication fails,
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/CompressedStreamUtils.java b/server/src/main/java/org/opensearch/cluster/coordination/CompressedStreamUtils.java
new file mode 100644
index 0000000000000..dc7b203eb7c4b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/coordination/CompressedStreamUtils.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.Version;
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.transport.BytesTransportRequest;
+
+import java.io.IOException;
+
+/**
+ * A helper class to utilize the compressed stream.
+ *
+ * @opensearch.internal
+ */
+public final class CompressedStreamUtils {
+    private static final Logger logger = LogManager.getLogger(CompressedStreamUtils.class);
+
+    public static BytesReference createCompressedStream(Version version, CheckedConsumer<StreamOutput, IOException> outputConsumer)
+        throws IOException {
+        final BytesStreamOutput bStream = new BytesStreamOutput();
+        try (StreamOutput stream = new OutputStreamStreamOutput(CompressorRegistry.defaultCompressor().threadLocalOutputStream(bStream))) {
+            stream.setVersion(version);
+            outputConsumer.accept(stream);
+        }
+        final BytesReference serializedByteRef = bStream.bytes();
+        logger.trace("serialized writable object for node version [{}] with size [{}]", version, serializedByteRef.length());
+        return serializedByteRef;
+    }
+
+    public static StreamInput decompressBytes(BytesTransportRequest request, NamedWriteableRegistry namedWriteableRegistry)
+        throws IOException {
+        final Compressor compressor = CompressorRegistry.compressor(request.bytes());
+        final StreamInput in;
+        if (compressor != null) {
+            in = new InputStreamStreamInput(compressor.threadLocalInputStream(request.bytes().streamInput()));
+        } else {
+            in = request.bytes().streamInput();
+        }
+        in.setVersion(request.version());
+        return new NamedWriteableAwareStreamInput(in, namedWriteableRegistry);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationMetadata.java b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationMetadata.java
index c7671cb9e9b2b..682ebfd474e7a 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationMetadata.java
@@ -32,15 +32,15 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -52,6 +52,11 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * Metadata for cluster coordination
+ *
+ * @opensearch.internal
+ */
 public class CoordinationMetadata implements Writeable, ToXContentFragment {
 
     public static final CoordinationMetadata EMPTY_METADATA = builder().build();
@@ -206,6 +211,11 @@ public String toString() {
             + '}';
     }
 
+    /**
+     * Builder for coordination metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private long term = 0;
         private VotingConfiguration lastCommittedConfiguration = VotingConfiguration.EMPTY_CONFIG;
@@ -253,6 +263,11 @@ public CoordinationMetadata build() {
         }
     }
 
+    /**
+     * Excluded nodes from voting config.
+     *
+     * @opensearch.internal
+     */
     public static class VotingConfigExclusion implements Writeable, ToXContentFragment {
         public static final String MISSING_VALUE_MARKER = "_absent_";
         private final String nodeId;
@@ -346,13 +361,22 @@ public String toString() {
 
     /**
      * A collection of persistent node ids, denoting the voting configuration for cluster state changes.
+     *
+     * @opensearch.internal
      */
     public static class VotingConfiguration implements Writeable, ToXContentFragment {
 
         public static final VotingConfiguration EMPTY_CONFIG = new VotingConfiguration(Collections.emptySet());
+        /**
+         * @deprecated As of 2.0, because supporting inclusive language, replaced by {@link #MUST_JOIN_ELECTED_CLUSTER_MANAGER}
+         */
+        @Deprecated
         public static final VotingConfiguration MUST_JOIN_ELECTED_MASTER = new VotingConfiguration(
             Collections.singleton("_must_join_elected_master_")
         );
+        public static final VotingConfiguration MUST_JOIN_ELECTED_CLUSTER_MANAGER = new VotingConfiguration(
+            Collections.singleton("_must_join_elected_cluster_manager_")
+        );
 
         private final Set<String> nodeIds;
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationState.java b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationState.java
index b28fde5d9cc16..a339852e6ed8d 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationState.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationState.java
@@ -35,8 +35,11 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -49,10 +52,13 @@
 import java.util.Set;
 
 import static org.opensearch.cluster.coordination.Coordinator.ZEN1_BWC_TERM;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreClusterStateEnabled;
 
 /**
  * The core class of the cluster state coordination algorithm, directly implementing the
  * <a href="https://github.com/elastic/elasticsearch-formal-models/blob/master/ZenWithTerms/tla/ZenWithTerms.tla">formal model</a>
+ *
+ * @opensearch.internal
  */
 public class CoordinationState {
 
@@ -62,8 +68,8 @@ public class CoordinationState {
 
     private final ElectionStrategy electionStrategy;
 
-    // persisted state
-    private final PersistedState persistedState;
+    // persisted state registry
+    private final PersistedStateRegistry persistedStateRegistry;
 
     // transient state
     private VoteCollection joinVotes;
@@ -72,12 +78,18 @@ public class CoordinationState {
     private long lastPublishedVersion;
     private VotingConfiguration lastPublishedConfiguration;
     private VoteCollection publishVotes;
-
-    public CoordinationState(DiscoveryNode localNode, PersistedState persistedState, ElectionStrategy electionStrategy) {
+    private final boolean isRemoteStateEnabled;
+
+    public CoordinationState(
+        DiscoveryNode localNode,
+        PersistedStateRegistry persistedStateRegistry,
+        ElectionStrategy electionStrategy,
+        Settings settings
+    ) {
         this.localNode = localNode;
 
-        // persisted state
-        this.persistedState = persistedState;
+        // persisted state registry
+        this.persistedStateRegistry = persistedStateRegistry;
         this.electionStrategy = electionStrategy;
 
         // transient state
@@ -85,16 +97,19 @@ public CoordinationState(DiscoveryNode localNode, PersistedState persistedState,
         this.startedJoinSinceLastReboot = false;
         this.electionWon = false;
         this.lastPublishedVersion = 0L;
-        this.lastPublishedConfiguration = persistedState.getLastAcceptedState().getLastAcceptedConfiguration();
+        this.lastPublishedConfiguration = persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL)
+            .getLastAcceptedState()
+            .getLastAcceptedConfiguration();
         this.publishVotes = new VoteCollection();
+        this.isRemoteStateEnabled = isRemoteStoreClusterStateEnabled(settings);
     }
 
     public long getCurrentTerm() {
-        return persistedState.getCurrentTerm();
+        return persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).getCurrentTerm();
     }
 
     public ClusterState getLastAcceptedState() {
-        return persistedState.getLastAcceptedState();
+        return persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).getLastAcceptedState();
     }
 
     public long getLastAcceptedTerm() {
@@ -184,7 +199,7 @@ public void setInitialState(ClusterState initialState) {
         assert initialState.getLastAcceptedConfiguration().isEmpty() == false;
         assert initialState.getLastCommittedConfiguration().isEmpty() == false;
 
-        persistedState.setLastAcceptedState(initialState);
+        persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).setLastAcceptedState(initialState);
     }
 
     /**
@@ -220,7 +235,7 @@ public Join handleStartJoin(StartJoinRequest startJoinRequest) {
             logger.debug("handleStartJoin: discarding {}: {}", joinVotes, reason);
         }
 
-        persistedState.setCurrentTerm(startJoinRequest.getTerm());
+        persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).setCurrentTerm(startJoinRequest.getTerm());
         assert getCurrentTerm() == startJoinRequest.getTerm();
         lastPublishedVersion = 0;
         lastPublishedConfiguration = getLastAcceptedConfiguration();
@@ -411,7 +426,7 @@ public PublishResponse handlePublishRequest(PublishRequest publishRequest) {
         }
         if (clusterState.term() == getLastAcceptedTerm() && clusterState.version() <= getLastAcceptedVersion()) {
             if (clusterState.term() == ZEN1_BWC_TERM
-                && clusterState.nodes().getMasterNode().equals(getLastAcceptedState().nodes().getMasterNode()) == false) {
+                && clusterState.nodes().getClusterManagerNode().equals(getLastAcceptedState().nodes().getClusterManagerNode()) == false) {
                 logger.debug(
                     "handling publish request in compatibility mode despite version mismatch (expected: >[{}], actual: [{}])",
                     getLastAcceptedVersion(),
@@ -434,7 +449,7 @@ public PublishResponse handlePublishRequest(PublishRequest publishRequest) {
             clusterState.version(),
             clusterState.term()
         );
-        persistedState.setLastAcceptedState(clusterState);
+        persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).setLastAcceptedState(clusterState);
         assert getLastAcceptedState() == clusterState;
 
         return new PublishResponse(clusterState.term(), clusterState.version());
@@ -488,6 +503,7 @@ public Optional<ApplyCommitRequest> handlePublishResponse(DiscoveryNode sourceNo
                 publishResponse.getVersion(),
                 publishResponse.getTerm()
             );
+            handlePreCommit();
             return Optional.of(new ApplyCommitRequest(localNode, publishResponse.getTerm(), publishResponse.getVersion()));
         }
 
@@ -545,10 +561,36 @@ public void handleCommit(ApplyCommitRequest applyCommit) {
             applyCommit.getVersion()
         );
 
-        persistedState.markLastAcceptedStateAsCommitted();
+        persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).markLastAcceptedStateAsCommitted();
         assert getLastCommittedConfiguration().equals(getLastAcceptedConfiguration());
     }
 
+    /**
+     * This method should be called just before sending the PublishRequest to all cluster nodes.
+     * @param clusterState The cluster state for which pre publish activities should happen.
+     */
+    public void handlePrePublish(ClusterState clusterState) {
+        // Publishing the current state to remote store before sending the cluster state to other nodes.
+        // This is to ensure the remote store is the single source of truth for current state. Even if the current node
+        // goes down after sending the cluster state to other nodes, we should be able to read the remote state and
+        // recover the cluster.
+        if (isRemoteStateEnabled) {
+            assert persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE) != null : "Remote state has not been initialized";
+            persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE).setLastAcceptedState(clusterState);
+        }
+    }
+
+    /**
+     * This method should be called just before sending the ApplyCommitRequest to all cluster nodes.
+     */
+    public void handlePreCommit() {
+        // Publishing the committed state to remote store before sending apply commit to other nodes.
+        if (isRemoteStateEnabled) {
+            assert persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE) != null : "Remote state has not been initialized";
+            persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE).markLastAcceptedStateAsCommitted();
+        }
+    }
+
     public void invariant() {
         assert getLastAcceptedTerm() <= getCurrentTerm();
         assert electionWon() == isElectionQuorum(joinVotes);
@@ -562,11 +604,13 @@ public void invariant() {
     }
 
     public void close() throws IOException {
-        persistedState.close();
+        IOUtils.close(persistedStateRegistry);
     }
 
     /**
      * Pluggable persistence layer for {@link CoordinationState}.
+     *
+     * @opensearch.internal
      */
     public interface PersistedState extends Closeable {
 
@@ -610,7 +654,8 @@ default void markLastAcceptedStateAsCommitted() {
                 metadataBuilder = Metadata.builder(lastAcceptedState.metadata());
                 metadataBuilder.coordinationMetadata(coordinationMetadata);
             }
-            // if we receive a commit from a Zen1 master that has not recovered its state yet, the cluster uuid might not been known yet.
+            // if we receive a commit from a Zen1 cluster-manager that has not recovered its state yet,
+            // the cluster uuid might not been known yet.
             assert lastAcceptedState.metadata().clusterUUID().equals(Metadata.UNKNOWN_CLUSTER_UUID) == false
                 || lastAcceptedState.term() == ZEN1_BWC_TERM : "received cluster state with empty cluster uuid but not Zen1 BWC term: "
                     + lastAcceptedState;
@@ -622,7 +667,8 @@ default void markLastAcceptedStateAsCommitted() {
                 metadataBuilder.clusterUUIDCommitted(true);
 
                 if (lastAcceptedState.term() != ZEN1_BWC_TERM) {
-                    // Zen1 masters never publish a committed cluster UUID so if we logged this it'd happen on on every update. Let's just
+                    // Zen1 cluster-managers never publish a committed cluster UUID so if we logged this it'd happen on on every update.
+                    // Let's just
                     // not log it at all in a 6.8/7.x rolling upgrade.
                     logger.info("cluster UUID set to [{}]", lastAcceptedState.metadata().clusterUUID());
                 }
@@ -637,6 +683,8 @@ default void close() throws IOException {}
 
     /**
      * A collection of votes, used to calculate quorums. Optionally records the Joins as well.
+     *
+     * @opensearch.internal
      */
     public static class VoteCollection {
 
@@ -644,7 +692,7 @@ public static class VoteCollection {
         private final Set<Join> joins;
 
         public boolean addVote(DiscoveryNode sourceNode) {
-            return sourceNode.isMasterNode() && nodes.put(sourceNode.getId(), sourceNode) == null;
+            return sourceNode.isClusterManagerNode() && nodes.put(sourceNode.getId(), sourceNode) == null;
         }
 
         public boolean addJoinVote(Join join) {
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationStateRejectedException.java b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationStateRejectedException.java
index 078424a079f02..8dc8d4295072a 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/CoordinationStateRejectedException.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/CoordinationStateRejectedException.java
@@ -33,7 +33,7 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
@@ -43,6 +43,8 @@
  * Occurrences of this exception don't always signal failures, but can often be just caused by the
  * asynchronous, distributed nature of the system. They will, for example, naturally happen during
  * leader election, if multiple nodes are trying to become leader at the same time.
+ *
+ * @opensearch.internal
  */
 public class CoordinationStateRejectedException extends OpenSearchException {
     public CoordinationStateRejectedException(String msg, Object... args) {
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java b/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
index 557f11f75d969..f587a73137c0a 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
@@ -35,9 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -58,23 +56,27 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterApplier;
 import org.opensearch.cluster.service.ClusterApplier.ClusterApplyListener;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ListenableFuture;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse.Empty;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.discovery.DiscoveryStats;
@@ -84,9 +86,9 @@
 import org.opensearch.discovery.SeedHostsResolver;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool.Names;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
@@ -105,11 +107,17 @@
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_ID;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID;
+import static org.opensearch.cluster.decommission.DecommissionHelper.nodeCommissioned;
 import static org.opensearch.gateway.ClusterStateUpdaters.hideStateIfNotRecovered;
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * The main lifecycle resource coordinator
+ *
+ * @opensearch.internal
+ */
 public class Coordinator extends AbstractLifecycleComponent implements Discovery {
 
     public static final long ZEN1_BWC_TERM = 0;
@@ -134,14 +142,15 @@ public class Coordinator extends AbstractLifecycleComponent implements Discovery
 
     private final Settings settings;
     private final boolean singleNodeDiscovery;
+    private volatile boolean localNodeCommissioned;
     private final ElectionStrategy electionStrategy;
     private final TransportService transportService;
-    private final MasterService masterService;
+    private final ClusterManagerService clusterManagerService;
     private final AllocationService allocationService;
     private final JoinHelper joinHelper;
     private final NodeRemovalClusterStateTaskExecutor nodeRemovalExecutor;
     private final Supplier<CoordinationState.PersistedState> persistedStateSupplier;
-    private final NoMasterBlockService noMasterBlockService;
+    private final NoClusterManagerBlockService noClusterManagerBlockService;
     final Object mutex = new Object(); // package-private to allow tests to call methods that assert that the mutex is held
     private final SetOnce<CoordinationState> coordinationState = new SetOnce<>(); // initialized on start-up (see doStart)
     private volatile ClusterState applierState; // the state that should be exposed to the cluster state applier
@@ -174,6 +183,8 @@ public class Coordinator extends AbstractLifecycleComponent implements Discovery
     private JoinHelper.JoinAccumulator joinAccumulator;
     private Optional<CoordinatorPublication> currentPublication = Optional.empty();
     private final NodeHealthService nodeHealthService;
+    private final PersistedStateRegistry persistedStateRegistry;
+    private final RemoteStoreNodeService remoteStoreNodeService;
 
     /**
      * @param nodeName The name of the node, used to name the {@link java.util.concurrent.ExecutorService} of the {@link SeedHostsResolver}.
@@ -186,7 +197,7 @@ public Coordinator(
         TransportService transportService,
         NamedWriteableRegistry namedWriteableRegistry,
         AllocationService allocationService,
-        MasterService masterService,
+        ClusterManagerService clusterManagerService,
         Supplier<CoordinationState.PersistedState> persistedStateSupplier,
         SeedHostsProvider seedHostsProvider,
         ClusterApplier clusterApplier,
@@ -194,11 +205,13 @@ public Coordinator(
         Random random,
         RerouteService rerouteService,
         ElectionStrategy electionStrategy,
-        NodeHealthService nodeHealthService
+        NodeHealthService nodeHealthService,
+        PersistedStateRegistry persistedStateRegistry,
+        RemoteStoreNodeService remoteStoreNodeService
     ) {
         this.settings = settings;
         this.transportService = transportService;
-        this.masterService = masterService;
+        this.clusterManagerService = clusterManagerService;
         this.allocationService = allocationService;
         this.onJoinValidators = JoinTaskExecutor.addBuiltInJoinValidators(onJoinValidators);
         this.singleNodeDiscovery = DiscoveryModule.isSingleNodeDiscovery(settings);
@@ -206,18 +219,21 @@ public Coordinator(
         this.joinHelper = new JoinHelper(
             settings,
             allocationService,
-            masterService,
+            clusterManagerService,
             transportService,
+            remoteStoreNodeService,
             this::getCurrentTerm,
-            this::getStateForMasterService,
+            this::getStateForClusterManagerService,
             this::handleJoinRequest,
             this::joinLeaderInTerm,
             this.onJoinValidators,
             rerouteService,
-            nodeHealthService
+            nodeHealthService,
+            this::onNodeCommissionStatusChange,
+            namedWriteableRegistry
         );
         this.persistedStateSupplier = persistedStateSupplier;
-        this.noMasterBlockService = new NoMasterBlockService(settings, clusterSettings);
+        this.noClusterManagerBlockService = new NoClusterManagerBlockService(settings, clusterSettings);
         this.lastKnownLeader = Optional.empty();
         this.lastJoin = Optional.empty();
         this.joinAccumulator = new InitialJoinAccumulator();
@@ -255,7 +271,7 @@ public Coordinator(
         );
         this.nodeRemovalExecutor = new NodeRemovalClusterStateTaskExecutor(allocationService, logger);
         this.clusterApplier = clusterApplier;
-        masterService.setClusterStateSupplier(this::getStateForMasterService);
+        clusterManagerService.setClusterStateSupplier(this::getStateForClusterManagerService);
         this.reconfigurator = new Reconfigurator(settings, clusterSettings);
         this.clusterBootstrapService = new ClusterBootstrapService(
             settings,
@@ -277,12 +293,15 @@ public Coordinator(
             joinHelper::logLastFailedJoinAttempt
         );
         this.nodeHealthService = nodeHealthService;
+        this.persistedStateRegistry = persistedStateRegistry;
+        this.localNodeCommissioned = true;
+        this.remoteStoreNodeService = remoteStoreNodeService;
     }
 
     private ClusterFormationState getClusterFormationState() {
         return new ClusterFormationState(
             settings,
-            getStateForMasterService(),
+            getStateForClusterManagerService(),
             peerFinder.getLastResolvedAddresses(),
             Stream.concat(Stream.of(getLocalNode()), StreamSupport.stream(peerFinder.getFoundPeers().spliterator(), false))
                 .collect(Collectors.toList()),
@@ -296,7 +315,7 @@ private void onLeaderFailure(Exception e) {
         synchronized (mutex) {
             if (mode != Mode.CANDIDATE) {
                 assert lastKnownLeader.isPresent();
-                logger.info(new ParameterizedMessage("master node [{}] failed, restarting discovery", lastKnownLeader.get()), e);
+                logger.info(new ParameterizedMessage("cluster-manager node [{}] failed, restarting discovery", lastKnownLeader.get()), e);
             }
             becomeCandidate("onLeaderFailure");
         }
@@ -305,7 +324,7 @@ private void onLeaderFailure(Exception e) {
     private void removeNode(DiscoveryNode discoveryNode, String reason) {
         synchronized (mutex) {
             if (mode == Mode.LEADER) {
-                masterService.submitStateUpdateTask(
+                clusterManagerService.submitStateUpdateTask(
                     "node-left",
                     new NodeRemovalClusterStateTaskExecutor.Task(discoveryNode, reason),
                     ClusterStateTaskConfig.build(Priority.IMMEDIATE),
@@ -336,11 +355,11 @@ void onFollowerCheckRequest(FollowerCheckRequest followerCheckRequest) {
             } else if (mode == Mode.FOLLOWER) {
                 logger.trace("onFollowerCheckRequest: responding successfully to {}", followerCheckRequest);
             } else if (joinHelper.isJoinPending()) {
-                logger.trace("onFollowerCheckRequest: rejoining master, responding successfully to {}", followerCheckRequest);
+                logger.trace("onFollowerCheckRequest: rejoining cluster-manager, responding successfully to {}", followerCheckRequest);
             } else {
-                logger.trace("onFollowerCheckRequest: received check from faulty master, rejecting {}", followerCheckRequest);
+                logger.trace("onFollowerCheckRequest: received check from faulty cluster-manager, rejecting {}", followerCheckRequest);
                 throw new CoordinationStateRejectedException(
-                    "onFollowerCheckRequest: received check from faulty master, rejecting " + followerCheckRequest
+                    "onFollowerCheckRequest: received check from faulty cluster-manager, rejecting " + followerCheckRequest
                 );
             }
         }
@@ -352,9 +371,9 @@ private void handleApplyCommit(ApplyCommitRequest applyCommitRequest, ActionList
 
             coordinationState.get().handleCommit(applyCommitRequest);
             final ClusterState committedState = hideStateIfNotRecovered(coordinationState.get().getLastAcceptedState());
-            applierState = mode == Mode.CANDIDATE ? clusterStateWithNoMasterBlock(committedState) : committedState;
+            applierState = mode == Mode.CANDIDATE ? clusterStateWithNoClusterManagerBlock(committedState) : committedState;
             if (applyCommitRequest.getSourceNode().equals(getLocalNode())) {
-                // master node applies the committed state at the end of the publication process, not here.
+                // cluster-manager node applies the committed state at the end of the publication process, not here.
                 applyListener.onResponse(null);
             } else {
                 clusterApplier.onNewClusterState(applyCommitRequest.toString(), () -> applierState, new ClusterApplyListener() {
@@ -381,7 +400,7 @@ PublishWithJoinResponse handlePublishRequest(PublishRequest publishRequest) {
             + getLocalNode();
 
         synchronized (mutex) {
-            final DiscoveryNode sourceNode = publishRequest.getAcceptedState().nodes().getMasterNode();
+            final DiscoveryNode sourceNode = publishRequest.getAcceptedState().nodes().getClusterManagerNode();
             logger.trace("handlePublishRequest: handling [{}] from [{}]", publishRequest, sourceNode);
 
             if (sourceNode.equals(getLocalNode()) && mode != Mode.LEADER) {
@@ -423,7 +442,7 @@ && getCurrentTerm() == ZEN1_BWC_TERM
             }
 
             if (publishRequest.getAcceptedState().term() > localState.term()) {
-                // only do join validation if we have not accepted state from this master yet
+                // only do join validation if we have not accepted state from this cluster manager yet
                 onJoinValidators.forEach(a -> a.accept(getLocalNode(), publishRequest.getAcceptedState()));
             }
 
@@ -507,13 +526,14 @@ private void startElection() {
         }
     }
 
-    private void abdicateTo(DiscoveryNode newMaster) {
+    private void abdicateTo(DiscoveryNode newClusterManager) {
         assert Thread.holdsLock(mutex);
         assert mode == Mode.LEADER : "expected to be leader on abdication but was " + mode;
-        assert newMaster.isMasterNode() : "should only abdicate to master-eligible node but was " + newMaster;
-        final StartJoinRequest startJoinRequest = new StartJoinRequest(newMaster, Math.max(getCurrentTerm(), maxTermSeen) + 1);
-        logger.info("abdicating to {} with term {}", newMaster, startJoinRequest.getTerm());
-        getLastAcceptedState().nodes().mastersFirstStream().forEach(node -> {
+        assert newClusterManager.isClusterManagerNode() : "should only abdicate to cluster-manager-eligible node but was "
+            + newClusterManager;
+        final StartJoinRequest startJoinRequest = new StartJoinRequest(newClusterManager, Math.max(getCurrentTerm(), maxTermSeen) + 1);
+        logger.info("abdicating to {} with term {}", newClusterManager, startJoinRequest.getTerm());
+        getLastAcceptedState().nodes().clusterManagersFirstStream().forEach(node -> {
             if (isZen1Node(node) == false) {
                 joinHelper.sendStartJoinRequest(startJoinRequest, node);
             }
@@ -521,7 +541,7 @@ private void abdicateTo(DiscoveryNode newMaster) {
         // handling of start join messages on the local node will be dispatched to the generic thread-pool
         assert mode == Mode.LEADER : "should still be leader after sending abdication messages " + mode;
         // explicitly move node to candidate state so that the next cluster state update task yields an onNoLongerMaster event
-        becomeCandidate("after abdicating to " + newMaster);
+        becomeCandidate("after abdicating to " + newClusterManager);
     }
 
     private static boolean localNodeMayWinElection(ClusterState lastAcceptedState) {
@@ -563,7 +583,7 @@ private Join joinLeaderInTerm(StartJoinRequest startJoinRequest) {
 
     private void handleJoinRequest(JoinRequest joinRequest, JoinHelper.JoinCallback joinCallback) {
         assert Thread.holdsLock(mutex) == false;
-        assert getLocalNode().isMasterNode() : getLocalNode() + " received a join but is not master-eligible";
+        assert getLocalNode().isClusterManagerNode() : getLocalNode() + " received a join but is not cluster-manager-eligible";
         logger.trace("handleJoinRequest: as {}, handling {}", mode, joinRequest);
 
         if (singleNodeDiscovery && joinRequest.getSourceNode().equals(getLocalNode()) == false) {
@@ -580,9 +600,9 @@ private void handleJoinRequest(JoinRequest joinRequest, JoinHelper.JoinCallback
         }
 
         transportService.connectToNode(joinRequest.getSourceNode(), ActionListener.wrap(ignore -> {
-            final ClusterState stateForJoinValidation = getStateForMasterService();
+            final ClusterState stateForJoinValidation = getStateForClusterManagerService();
 
-            if (stateForJoinValidation.nodes().isLocalNodeElectedMaster()) {
+            if (stateForJoinValidation.nodes().isLocalNodeElectedClusterManager()) {
                 onJoinValidators.forEach(a -> a.accept(joinRequest.getSourceNode(), stateForJoinValidation));
                 if (stateForJoinValidation.getBlocks().hasGlobalBlock(STATE_NOT_RECOVERED_BLOCK) == false) {
                     // we do this in a couple of places including the cluster update thread. This one here is really just best effort
@@ -591,6 +611,9 @@ private void handleJoinRequest(JoinRequest joinRequest, JoinHelper.JoinCallback
                         joinRequest.getSourceNode().getVersion(),
                         stateForJoinValidation.getNodes().getMinNodeVersion()
                     );
+                    // we are checking source node commission status here to reject any join request coming from a decommissioned node
+                    // even before executing the join task to fail fast
+                    JoinTaskExecutor.ensureNodeCommissioned(joinRequest.getSourceNode(), stateForJoinValidation.metadata());
                 }
                 sendValidateJoinRequest(stateForJoinValidation, joinRequest, joinCallback);
             } else {
@@ -668,11 +691,11 @@ void becomeCandidate(String method) {
             lagDetector.clearTrackedNodes();
 
             if (prevMode == Mode.LEADER) {
-                cleanMasterService();
+                cleanClusterManagerService();
             }
 
-            if (applierState.nodes().getMasterNodeId() != null) {
-                applierState = clusterStateWithNoMasterBlock(applierState);
+            if (applierState.nodes().getClusterManagerNodeId() != null) {
+                applierState = clusterStateWithNoClusterManagerBlock(applierState);
                 clusterApplier.onNewClusterState("becoming candidate: " + method, () -> applierState, (source, e) -> {});
             }
         }
@@ -683,7 +706,7 @@ void becomeCandidate(String method) {
     void becomeLeader(String method) {
         assert Thread.holdsLock(mutex) : "Coordinator mutex not held";
         assert mode == Mode.CANDIDATE : "expected candidate but was " + mode;
-        assert getLocalNode().isMasterNode() : getLocalNode() + " became a leader but is not master-eligible";
+        assert getLocalNode().isClusterManagerNode() : getLocalNode() + " became a leader but is not cluster-manager-eligible";
 
         logger.debug(
             "{}: coordinator becoming LEADER in term {} (was {}, lastKnownLeader was [{}])",
@@ -709,7 +732,7 @@ void becomeLeader(String method) {
 
     void becomeFollower(String method, DiscoveryNode leaderNode) {
         assert Thread.holdsLock(mutex) : "Coordinator mutex not held";
-        assert leaderNode.isMasterNode() : leaderNode + " became a leader but is not master-eligible";
+        assert leaderNode.isClusterManagerNode() : leaderNode + " became a leader but is not cluster-manager-eligible";
         assert mode != Mode.LEADER : "do not switch to follower from leader (should be candidate first)";
 
         if (mode == Mode.FOLLOWER && Optional.of(leaderNode).equals(lastKnownLeader)) {
@@ -750,17 +773,17 @@ void becomeFollower(String method, DiscoveryNode leaderNode) {
         lagDetector.clearTrackedNodes();
     }
 
-    private void cleanMasterService() {
-        masterService.submitStateUpdateTask("clean-up after stepping down as master", new LocalClusterUpdateTask() {
+    private void cleanClusterManagerService() {
+        clusterManagerService.submitStateUpdateTask("clean-up after stepping down as cluster-manager", new LocalClusterUpdateTask() {
             @Override
             public void onFailure(String source, Exception e) {
                 // ignore
-                logger.trace("failed to clean-up after stepping down as master", e);
+                logger.trace("failed to clean-up after stepping down as cluster-manager", e);
             }
 
             @Override
             public ClusterTasksResult<LocalClusterUpdateTask> execute(ClusterState currentState) {
-                if (currentState.nodes().isLocalNodeElectedMaster() == false) {
+                if (currentState.nodes().isLocalNodeElectedClusterManager() == false) {
                     allocationService.cleanCaches();
                 }
                 return unchanged();
@@ -806,8 +829,7 @@ boolean publicationInProgress() {
     @Override
     protected void doStart() {
         synchronized (mutex) {
-            CoordinationState.PersistedState persistedState = persistedStateSupplier.get();
-            coordinationState.set(new CoordinationState(getLocalNode(), persistedState, electionStrategy));
+            coordinationState.set(new CoordinationState(getLocalNode(), persistedStateRegistry, electionStrategy, settings));
             peerFinder.setCurrentTerm(getCurrentTerm());
             configuredHostsResolver.start();
             final ClusterState lastAcceptedState = coordinationState.get().getLastAcceptedState();
@@ -833,7 +855,7 @@ protected void doStart() {
                 .blocks(
                     ClusterBlocks.builder()
                         .addGlobalBlock(STATE_NOT_RECOVERED_BLOCK)
-                        .addGlobalBlock(noMasterBlockService.getNoMasterBlock())
+                        .addGlobalBlock(noClusterManagerBlockService.getNoClusterManagerBlock())
                 )
                 .nodes(DiscoveryNodes.builder().add(getLocalNode()).localNodeId(getLocalNode().getId()))
                 .build();
@@ -879,7 +901,8 @@ public void invariant() {
             assert peerFinder.getCurrentTerm() == getCurrentTerm();
             assert followersChecker.getFastResponseState().term == getCurrentTerm() : followersChecker.getFastResponseState();
             assert followersChecker.getFastResponseState().mode == getMode() : followersChecker.getFastResponseState();
-            assert (applierState.nodes().getMasterNodeId() == null) == applierState.blocks().hasGlobalBlockWithId(NO_MASTER_BLOCK_ID);
+            assert (applierState.nodes().getClusterManagerNodeId() == null) == applierState.blocks()
+                .hasGlobalBlockWithId(NO_CLUSTER_MANAGER_BLOCK_ID);
             assert preVoteCollector.getPreVoteResponse().equals(getPreVoteResponse()) : preVoteCollector + " vs " + getPreVoteResponse();
 
             assert lagDetector.getTrackedNodes().contains(getLocalNode()) == false : lagDetector.getTrackedNodes();
@@ -888,7 +911,7 @@ public void invariant() {
                 + lagDetector.getTrackedNodes();
 
             if (mode == Mode.LEADER) {
-                final boolean becomingMaster = getStateForMasterService().term() != getCurrentTerm();
+                final boolean becomingClusterManager = getStateForClusterManagerService().term() != getCurrentTerm();
 
                 assert coordinationState.get().electionWon();
                 assert lastKnownLeader.isPresent() && lastKnownLeader.get().equals(getLocalNode());
@@ -896,16 +919,18 @@ public void invariant() {
                 assert peerFinderLeader.equals(lastKnownLeader) : peerFinderLeader;
                 assert electionScheduler == null : electionScheduler;
                 assert prevotingRound == null : prevotingRound;
-                assert becomingMaster || getStateForMasterService().nodes().getMasterNodeId() != null : getStateForMasterService();
+                assert becomingClusterManager || getStateForClusterManagerService().nodes().getClusterManagerNodeId() != null
+                    : getStateForClusterManagerService();
                 assert leaderChecker.leader() == null : leaderChecker.leader();
-                assert getLocalNode().equals(applierState.nodes().getMasterNode())
-                    || (applierState.nodes().getMasterNodeId() == null && applierState.term() < getCurrentTerm());
+                assert getLocalNode().equals(applierState.nodes().getClusterManagerNode())
+                    || (applierState.nodes().getClusterManagerNodeId() == null && applierState.term() < getCurrentTerm());
                 assert preVoteCollector.getLeader() == getLocalNode() : preVoteCollector;
                 assert clusterFormationFailureHelper.isRunning() == false;
 
                 final boolean activePublication = currentPublication.map(CoordinatorPublication::isActiveForCurrentLeader).orElse(false);
-                if (becomingMaster && activePublication == false) {
-                    // cluster state update task to become master is submitted to MasterService, but publication has not started yet
+                if (becomingClusterManager && activePublication == false) {
+                    // cluster state update task to become cluster-manager is submitted to MasterService,
+                    // but publication has not started yet
                     assert followersChecker.getKnownFollowers().isEmpty() : followersChecker.getKnownFollowers();
                 } else {
                     final ClusterState lastPublishedState;
@@ -924,7 +949,7 @@ assert getLocalNode().equals(applierState.nodes().getMasterNode())
                         + followersChecker.getKnownFollowers();
                 }
 
-                assert becomingMaster
+                assert becomingClusterManager
                     || activePublication
                     || coordinationState.get()
                         .getLastAcceptedConfiguration()
@@ -939,12 +964,12 @@ assert getLocalNode().equals(applierState.nodes().getMasterNode())
                 assert peerFinderLeader.equals(lastKnownLeader) : peerFinderLeader;
                 assert electionScheduler == null : electionScheduler;
                 assert prevotingRound == null : prevotingRound;
-                assert getStateForMasterService().nodes().getMasterNodeId() == null : getStateForMasterService();
-                assert leaderChecker.currentNodeIsMaster() == false;
+                assert getStateForClusterManagerService().nodes().getClusterManagerNodeId() == null : getStateForClusterManagerService();
+                assert leaderChecker.currentNodeIsClusterManager() == false;
                 assert lastKnownLeader.equals(Optional.of(leaderChecker.leader()));
                 assert followersChecker.getKnownFollowers().isEmpty();
-                assert lastKnownLeader.get().equals(applierState.nodes().getMasterNode())
-                    || (applierState.nodes().getMasterNodeId() == null
+                assert lastKnownLeader.get().equals(applierState.nodes().getClusterManagerNode())
+                    || (applierState.nodes().getClusterManagerNodeId() == null
                         && (applierState.term() < getCurrentTerm() || applierState.version() < getLastAcceptedState().version()));
                 assert currentPublication.map(Publication::isCommitted).orElse(true);
                 assert preVoteCollector.getLeader().equals(lastKnownLeader.get()) : preVoteCollector;
@@ -954,11 +979,11 @@ assert getLocalNode().equals(applierState.nodes().getMasterNode())
                 assert joinAccumulator instanceof JoinHelper.CandidateJoinAccumulator;
                 assert peerFinderLeader.isPresent() == false : peerFinderLeader;
                 assert prevotingRound == null || electionScheduler != null;
-                assert getStateForMasterService().nodes().getMasterNodeId() == null : getStateForMasterService();
-                assert leaderChecker.currentNodeIsMaster() == false;
+                assert getStateForClusterManagerService().nodes().getClusterManagerNodeId() == null : getStateForClusterManagerService();
+                assert leaderChecker.currentNodeIsClusterManager() == false;
                 assert leaderChecker.leader() == null : leaderChecker.leader();
                 assert followersChecker.getKnownFollowers().isEmpty();
-                assert applierState.nodes().getMasterNodeId() == null;
+                assert applierState.nodes().getClusterManagerNodeId() == null;
                 assert currentPublication.map(Publication::isCommitted).orElse(true);
                 assert preVoteCollector.getLeader() == null : preVoteCollector;
                 assert clusterFormationFailureHelper.isRunning();
@@ -967,7 +992,7 @@ assert getLocalNode().equals(applierState.nodes().getMasterNode())
     }
 
     public boolean isInitialConfigurationSet() {
-        return getStateForMasterService().getLastAcceptedConfiguration().isEmpty() == false;
+        return getStateForClusterManagerService().getLastAcceptedConfiguration().isEmpty() == false;
     }
 
     /**
@@ -979,17 +1004,17 @@ public boolean isInitialConfigurationSet() {
      */
     public boolean setInitialConfiguration(final VotingConfiguration votingConfiguration) {
         synchronized (mutex) {
-            final ClusterState currentState = getStateForMasterService();
+            final ClusterState currentState = getStateForClusterManagerService();
 
             if (isInitialConfigurationSet()) {
                 logger.debug("initial configuration already set, ignoring {}", votingConfiguration);
                 return false;
             }
 
-            if (getLocalNode().isMasterNode() == false) {
-                logger.debug("skip setting initial configuration as local node is not a master-eligible node");
+            if (getLocalNode().isClusterManagerNode() == false) {
+                logger.debug("skip setting initial configuration as local node is not a cluster-manager-eligible node");
                 throw new CoordinationStateRejectedException(
-                    "this node is not master-eligible, but cluster bootstrapping can only happen on a master-eligible node"
+                    "this node is not cluster-manager-eligible, but cluster bootstrapping can only happen on a cluster-manager-eligible node"
                 );
             }
 
@@ -1046,25 +1071,27 @@ ClusterState improveConfiguration(ClusterState clusterState) {
 
         // exclude any nodes whose ID is in the voting config exclusions list ...
         final Stream<String> excludedNodeIds = clusterState.getVotingConfigExclusions().stream().map(VotingConfigExclusion::getNodeId);
-        // ... and also automatically exclude the node IDs of master-ineligible nodes that were previously master-eligible and are still in
-        // the voting config. We could exclude all the master-ineligible nodes here, but there could be quite a few of them and that makes
+        // ... and also automatically exclude the node IDs of cluster-manager-ineligible nodes that were previously cluster-manager-eligible
+        // and are still in
+        // the voting config. We could exclude all the cluster-manager-ineligible nodes here, but there could be quite a few of them and
+        // that makes
         // the logging much harder to follow.
-        final Stream<String> masterIneligibleNodeIdsInVotingConfig = StreamSupport.stream(clusterState.nodes().spliterator(), false)
+        final Stream<String> clusterManagerIneligibleNodeIdsInVotingConfig = StreamSupport.stream(clusterState.nodes().spliterator(), false)
             .filter(
-                n -> n.isMasterNode() == false
+                n -> n.isClusterManagerNode() == false
                     && (clusterState.getLastAcceptedConfiguration().getNodeIds().contains(n.getId())
                         || clusterState.getLastCommittedConfiguration().getNodeIds().contains(n.getId()))
             )
             .map(DiscoveryNode::getId);
 
         final Set<DiscoveryNode> liveNodes = StreamSupport.stream(clusterState.nodes().spliterator(), false)
-            .filter(DiscoveryNode::isMasterNode)
+            .filter(DiscoveryNode::isClusterManagerNode)
             .filter(coordinationState.get()::containsJoinVoteFor)
             .filter(discoveryNode -> isZen1Node(discoveryNode) == false)
             .collect(Collectors.toSet());
         final VotingConfiguration newConfig = reconfigurator.reconfigure(
             liveNodes,
-            Stream.concat(masterIneligibleNodeIdsInVotingConfig, excludedNodeIds).collect(Collectors.toSet()),
+            Stream.concat(clusterManagerIneligibleNodeIdsInVotingConfig, excludedNodeIds).collect(Collectors.toSet()),
             getLocalNode(),
             clusterState.getLastAcceptedConfiguration()
         );
@@ -1099,7 +1126,8 @@ static boolean validVotingConfigExclusionState(ClusterState clusterState) {
             .map(VotingConfigExclusion::getNodeId)
             .collect(Collectors.toSet());
         for (DiscoveryNode node : clusterState.getNodes()) {
-            if (node.isMasterNode() && (nodeIdsWithAbsentName.contains(node.getId()) || nodeNamesWithAbsentId.contains(node.getName()))) {
+            if (node.isClusterManagerNode()
+                && (nodeIdsWithAbsentName.contains(node.getId()) || nodeNamesWithAbsentId.contains(node.getName()))) {
                 return false;
             }
         }
@@ -1117,7 +1145,7 @@ private void scheduleReconfigurationIfNeeded() {
         final ClusterState state = getLastAcceptedState();
         if (improveConfiguration(state) != state && reconfigurationTaskScheduled.compareAndSet(false, true)) {
             logger.trace("scheduling reconfiguration");
-            masterService.submitStateUpdateTask("reconfigure", new ClusterStateUpdateTask(Priority.URGENT) {
+            clusterManagerService.submitStateUpdateTask("reconfigure", new ClusterStateUpdateTask(Priority.URGENT) {
                 @Override
                 public ClusterState execute(ClusterState currentState) {
                     reconfigurationTaskScheduled.set(false);
@@ -1137,7 +1165,7 @@ public void onFailure(String source, Exception e) {
 
     // exposed for tests
     boolean missingJoinVoteFrom(DiscoveryNode node) {
-        return node.isMasterNode() && coordinationState.get().containsJoinVoteFor(node) == false;
+        return node.isClusterManagerNode() && coordinationState.get().containsJoinVoteFor(node) == false;
     }
 
     private void handleJoin(Join join) {
@@ -1146,13 +1174,14 @@ private void handleJoin(Join join) {
 
             if (coordinationState.get().electionWon()) {
                 // If we have already won the election then the actual join does not matter for election purposes, so swallow any exception
-                final boolean isNewJoinFromMasterEligibleNode = handleJoinIgnoringExceptions(join);
+                final boolean isNewJoinFromClusterManagerEligibleNode = handleJoinIgnoringExceptions(join);
 
-                // If we haven't completely finished becoming master then there's already a publication scheduled which will, in turn,
+                // If we haven't completely finished becoming cluster-manager then there's already a publication scheduled which will, in
+                // turn,
                 // schedule a reconfiguration if needed. It's benign to schedule a reconfiguration anyway, but it might fail if it wins the
                 // race against the election-winning publication and log a big error message, which we can prevent by checking this here:
-                final boolean establishedAsMaster = mode == Mode.LEADER && getLastAcceptedState().term() == getCurrentTerm();
-                if (isNewJoinFromMasterEligibleNode && establishedAsMaster && publicationInProgress() == false) {
+                final boolean establishedAsClusterManager = mode == Mode.LEADER && getLastAcceptedState().term() == getCurrentTerm();
+                if (isNewJoinFromClusterManagerEligibleNode && establishedAsClusterManager && publicationInProgress() == false) {
                     scheduleReconfigurationIfNeeded();
                 }
             } else {
@@ -1191,29 +1220,30 @@ private List<DiscoveryNode> getDiscoveredNodes() {
         return nodes;
     }
 
-    ClusterState getStateForMasterService() {
+    ClusterState getStateForClusterManagerService() {
         synchronized (mutex) {
-            // expose last accepted cluster state as base state upon which the master service
+            // expose last accepted cluster state as base state upon which the cluster_manager service
             // speculatively calculates the next cluster state update
             final ClusterState clusterState = coordinationState.get().getLastAcceptedState();
             if (mode != Mode.LEADER || clusterState.term() != getCurrentTerm()) {
-                // the master service checks if the local node is the master node in order to fail execution of the state update early
-                return clusterStateWithNoMasterBlock(clusterState);
+                // the cluster-manager service checks if the local node is the cluster-manager node in order to fail execution of the state
+                // update early
+                return clusterStateWithNoClusterManagerBlock(clusterState);
             }
             return clusterState;
         }
     }
 
-    private ClusterState clusterStateWithNoMasterBlock(ClusterState clusterState) {
-        if (clusterState.nodes().getMasterNodeId() != null) {
+    private ClusterState clusterStateWithNoClusterManagerBlock(ClusterState clusterState) {
+        if (clusterState.nodes().getClusterManagerNodeId() != null) {
             // remove block if it already exists before adding new one
-            assert clusterState.blocks().hasGlobalBlockWithId(NO_MASTER_BLOCK_ID) == false
+            assert clusterState.blocks().hasGlobalBlockWithId(NO_CLUSTER_MANAGER_BLOCK_ID) == false
                 : "NO_MASTER_BLOCK should only be added by Coordinator";
             final ClusterBlocks clusterBlocks = ClusterBlocks.builder()
                 .blocks(clusterState.blocks())
-                .addGlobalBlock(noMasterBlockService.getNoMasterBlock())
+                .addGlobalBlock(noClusterManagerBlockService.getNoClusterManagerBlock())
                 .build();
-            final DiscoveryNodes discoveryNodes = new DiscoveryNodes.Builder(clusterState.nodes()).masterNodeId(null).build();
+            final DiscoveryNodes discoveryNodes = new DiscoveryNodes.Builder(clusterState.nodes()).clusterManagerNodeId(null).build();
             return ClusterState.builder(clusterState).blocks(clusterBlocks).nodes(discoveryNodes).build();
         } else {
             return clusterState;
@@ -1231,14 +1261,16 @@ public void publish(
                 if (mode != Mode.LEADER || getCurrentTerm() != clusterChangedEvent.state().term()) {
                     logger.debug(
                         () -> new ParameterizedMessage(
-                            "[{}] failed publication as node is no longer master for term {}",
+                            "[{}] failed publication as node is no longer cluster-manager for term {}",
                             clusterChangedEvent.source(),
                             clusterChangedEvent.state().term()
                         )
                     );
                     publishListener.onFailure(
                         new FailedToCommitClusterStateException(
-                            "node is no longer master for term " + clusterChangedEvent.state().term() + " while handling publication"
+                            "node is no longer cluster-manager for term "
+                                + clusterChangedEvent.state().term()
+                                + " while handling publication"
                         )
                     );
                     return;
@@ -1284,6 +1316,7 @@ assert getLocalNode().equals(clusterState.getNodes().get(getLocalNode().getId())
                 leaderChecker.setCurrentNodes(publishNodes);
                 followersChecker.setCurrentNodes(publishNodes);
                 lagDetector.setTrackedNodes(publishNodes);
+                coordinationState.get().handlePrePublish(clusterState);
                 publication.start(followersChecker.getFaultyNodes());
             }
         } catch (Exception e) {
@@ -1296,16 +1329,26 @@ assert getLocalNode().equals(clusterState.getNodes().get(getLocalNode().getId())
     // deserialized from the resulting JSON
     private boolean assertPreviousStateConsistency(ClusterChangedEvent event) {
         assert event.previousState() == coordinationState.get().getLastAcceptedState()
-            || XContentHelper.convertToMap(JsonXContent.jsonXContent, Strings.toString(event.previousState()), false)
+            || XContentHelper.convertToMap(
+                JsonXContent.jsonXContent,
+                Strings.toString(MediaTypeRegistry.JSON, event.previousState()),
+                false
+            )
                 .equals(
                     XContentHelper.convertToMap(
                         JsonXContent.jsonXContent,
-                        Strings.toString(clusterStateWithNoMasterBlock(coordinationState.get().getLastAcceptedState())),
+                        Strings.toString(
+                            MediaTypeRegistry.JSON,
+                            clusterStateWithNoClusterManagerBlock(coordinationState.get().getLastAcceptedState())
+                        ),
                         false
                     )
-                ) : Strings.toString(event.previousState())
+                ) : Strings.toString(MediaTypeRegistry.JSON, event.previousState())
                     + " vs "
-                    + Strings.toString(clusterStateWithNoMasterBlock(coordinationState.get().getLastAcceptedState()));
+                    + Strings.toString(
+                        MediaTypeRegistry.JSON,
+                        clusterStateWithNoClusterManagerBlock(coordinationState.get().getLastAcceptedState())
+                    );
         return true;
     }
 
@@ -1338,12 +1381,22 @@ public Collection<BiConsumer<DiscoveryNode, ClusterState>> getOnJoinValidators()
         return onJoinValidators;
     }
 
+    /**
+     * The mode of the coordinator.
+     *
+     * @opensearch.internal
+     */
     public enum Mode {
         CANDIDATE,
         LEADER,
         FOLLOWER
     }
 
+    /**
+     * The coordinator peer finder.
+     *
+     * @opensearch.internal
+     */
     private class CoordinatorPeerFinder extends PeerFinder {
 
         CoordinatorPeerFinder(
@@ -1361,10 +1414,10 @@ private class CoordinatorPeerFinder extends PeerFinder {
         }
 
         @Override
-        protected void onActiveMasterFound(DiscoveryNode masterNode, long term) {
+        protected void onActiveClusterManagerFound(DiscoveryNode clusterManagerNode, long term) {
             synchronized (mutex) {
-                ensureTermAtLeast(masterNode, term);
-                joinHelper.sendJoinRequest(masterNode, getCurrentTerm(), joinWithDestination(lastJoin, masterNode, term));
+                ensureTermAtLeast(clusterManagerNode, term);
+                joinHelper.sendJoinRequest(clusterManagerNode, getCurrentTerm(), joinWithDestination(lastJoin, clusterManagerNode, term));
             }
         }
 
@@ -1399,10 +1452,20 @@ protected void onFoundPeersUpdated() {
         }
     }
 
+    // package-visible for testing
+    synchronized void onNodeCommissionStatusChange(boolean localNodeCommissioned) {
+        this.localNodeCommissioned = localNodeCommissioned;
+        peerFinder.onNodeCommissionStatusChange(localNodeCommissioned);
+    }
+
+    public boolean localNodeCommissioned() {
+        return localNodeCommissioned;
+    }
+
     private void startElectionScheduler() {
         assert electionScheduler == null : electionScheduler;
 
-        if (getLocalNode().isMasterNode() == false) {
+        if (getLocalNode().isClusterManagerNode() == false) {
             return;
         }
 
@@ -1425,6 +1488,14 @@ public void run() {
                             return;
                         }
 
+                        // if either the localNodeCommissioned flag or the last accepted state thinks it should skip pre voting, we will
+                        // acknowledge it
+                        if (nodeCommissioned(lastAcceptedState.nodes().getLocalNode(), lastAcceptedState.metadata()) == false
+                            || localNodeCommissioned == false) {
+                            logger.debug("skip prevoting as local node is decommissioned");
+                            return;
+                        }
+
                         if (prevotingRound != null) {
                             prevotingRound.close();
                         }
@@ -1467,6 +1538,11 @@ boolean cancelCommittedPublication() {
         }
     }
 
+    /**
+     * The coordinator publication.
+     *
+     * @opensearch.internal
+     */
     class CoordinatorPublication extends Publication {
 
         private final PublishRequest publishRequest;
@@ -1611,12 +1687,12 @@ public void onSuccess(String source) {
                                         boolean attemptReconfiguration = true;
                                         final ClusterState state = getLastAcceptedState(); // committed state
                                         if (localNodeMayWinElection(state) == false) {
-                                            final List<DiscoveryNode> masterCandidates = completedNodes().stream()
-                                                .filter(DiscoveryNode::isMasterNode)
+                                            final List<DiscoveryNode> clusterManagerCandidates = completedNodes().stream()
+                                                .filter(DiscoveryNode::isClusterManagerNode)
                                                 .filter(node -> nodeMayWinElection(state, node))
                                                 .filter(node -> {
-                                                    // check if master candidate would be able to get an election quorum if we were to
-                                                    // abdicate to it. Assume that every node that completed the publication can provide
+                                                    // check if cluster_manager candidate would be able to get an election quorum if we were
+                                                    // to abdicate to it. Assume that every node that completed the publication can provide
                                                     // a vote in that next election and has the latest state.
                                                     final long futureElectionTerm = state.term() + 1;
                                                     final VoteCollection futureVoteCollection = new VoteCollection();
@@ -1636,8 +1712,8 @@ public void onSuccess(String source) {
                                                     );
                                                 })
                                                 .collect(Collectors.toList());
-                                            if (masterCandidates.isEmpty() == false) {
-                                                abdicateTo(masterCandidates.get(random.nextInt(masterCandidates.size())));
+                                            if (clusterManagerCandidates.isEmpty() == false) {
+                                                abdicateTo(clusterManagerCandidates.get(random.nextInt(clusterManagerCandidates.size())));
                                                 attemptReconfiguration = false;
                                             }
                                         }
@@ -1663,7 +1739,7 @@ public void onFailure(Exception e) {
                     cancelTimeoutHandlers();
 
                     final FailedToCommitClusterStateException exception = new FailedToCommitClusterStateException("publication failed", e);
-                    ackListener.onNodeAck(getLocalNode(), exception); // other nodes have acked, but not the master.
+                    ackListener.onNodeAck(getLocalNode(), exception); // other nodes have acked, but not the cluster manager.
                     publishListener.onFailure(exception);
                 }
             }, OpenSearchExecutors.newDirectExecutorService(), transportService.getThreadPool().getThreadContext());
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/DetachClusterCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/DetachClusterCommand.java
index 49d88fd33c724..d17ef31f1b818 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/DetachClusterCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/DetachClusterCommand.java
@@ -41,15 +41,20 @@
 import java.io.IOException;
 import java.nio.file.Path;
 
+/**
+ * Command to detach a node from the cluster
+ *
+ * @opensearch.internal
+ */
 public class DetachClusterCommand extends OpenSearchNodeCommand {
 
     static final String NODE_DETACHED_MSG = "Node was successfully detached from the cluster";
     static final String CONFIRMATION_MSG = DELIMITER
         + "\n"
         + "You should only run this tool if you have permanently lost all of the\n"
-        + "master-eligible nodes in this cluster and you cannot restore the cluster\n"
+        + "cluster-manager-eligible nodes in this cluster and you cannot restore the cluster\n"
         + "from a snapshot, or you have already unsafely bootstrapped a new cluster\n"
-        + "by running `opensearch-node unsafe-bootstrap` on a master-eligible\n"
+        + "by running `opensearch-node unsafe-bootstrap` on a cluster-manager-eligible\n"
         + "node that belonged to the same cluster as this node. This tool can cause\n"
         + "arbitrary data loss and its use should be your last resort.\n"
         + "\n"
@@ -86,8 +91,8 @@ protected void processNodePaths(Terminal terminal, Path[] dataPaths, int nodeLoc
     // package-private for tests
     static Metadata updateMetadata(Metadata oldMetadata) {
         final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder()
-            .lastAcceptedConfiguration(CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_MASTER)
-            .lastCommittedConfiguration(CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_MASTER)
+            .lastAcceptedConfiguration(CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_CLUSTER_MANAGER)
+            .lastCommittedConfiguration(CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_CLUSTER_MANAGER)
             .term(0)
             .build();
         return Metadata.builder(oldMetadata).coordinationMetadata(coordinationMetadata).clusterUUIDCommitted(false).build();
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ElectionSchedulerFactory.java b/server/src/main/java/org/opensearch/cluster/coordination/ElectionSchedulerFactory.java
index f0ec9681d76cc..828db5864d28b 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ElectionSchedulerFactory.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ElectionSchedulerFactory.java
@@ -56,6 +56,8 @@
  * randomly at reasonably high frequency and backing off (linearly) until one of them succeeds. We also place an upper bound on the backoff
  * so that if elections are failing due to a network partition that lasts for a long time then when the partition heals there is an election
  * attempt reasonably quickly.
+ *
+ * @opensearch.internal
  */
 public class ElectionSchedulerFactory {
 
@@ -181,6 +183,11 @@ public String toString() {
             + '}';
     }
 
+    /**
+     * The Election scheduler.
+     *
+     * @opensearch.internal
+     */
     private class ElectionScheduler implements Releasable {
         private final AtomicBoolean isClosed = new AtomicBoolean();
         private final AtomicLong attempt = new AtomicLong();
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ElectionStrategy.java b/server/src/main/java/org/opensearch/cluster/coordination/ElectionStrategy.java
index f3f7fd0c1b072..c6ea4649faaf0 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ElectionStrategy.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ElectionStrategy.java
@@ -38,6 +38,8 @@
 /**
  * Allows plugging in a custom election strategy, restricting the notion of an election quorum.
  * Custom additional quorum restrictions can be defined by implementing the {@link #satisfiesAdditionalQuorumConstraints} method.
+ *
+ * @opensearch.internal
  */
 public abstract class ElectionStrategy {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/FailedToCommitClusterStateException.java b/server/src/main/java/org/opensearch/cluster/coordination/FailedToCommitClusterStateException.java
index 59cd94aecdd57..8379bcaa0f0d8 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/FailedToCommitClusterStateException.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/FailedToCommitClusterStateException.java
@@ -32,12 +32,14 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown when failing to publish a cluster state. See {@link ClusterStatePublisher} for more details.
+ *
+ * @opensearch.internal
  */
 public class FailedToCommitClusterStateException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/FollowersChecker.java b/server/src/main/java/org/opensearch/cluster/coordination/FollowersChecker.java
index c5fcee712b683..f69a4f771cf21 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/FollowersChecker.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/FollowersChecker.java
@@ -38,12 +38,13 @@
 import org.opensearch.cluster.coordination.Coordinator.Mode;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.threadpool.ThreadPool.Names;
@@ -55,7 +56,6 @@
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportRequestOptions.Type;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -76,6 +76,8 @@
  * follower has failed the leader will remove it from the cluster. We are fairly lenient, possibly allowing multiple checks to fail before
  * considering a follower to be faulty, to allow for a brief network partition or a long GC cycle to occur without triggering the removal of
  * a node and the consequent shard reallocation.
+ *
+ * @opensearch.internal
  */
 public class FollowersChecker {
 
@@ -166,7 +168,7 @@ public void setCurrentNodes(DiscoveryNodes discoveryNodes) {
             followerCheckers.keySet().removeIf(isUnknownNode);
             faultyNodes.removeIf(isUnknownNode);
 
-            discoveryNodes.mastersFirstStream().forEach(discoveryNode -> {
+            discoveryNodes.clusterManagersFirstStream().forEach(discoveryNode -> {
                 if (discoveryNode.equals(discoveryNodes.getLocalNode()) == false
                     && followerCheckers.containsKey(discoveryNode) == false
                     && faultyNodes.contains(discoveryNode) == false) {
@@ -292,6 +294,11 @@ private void handleDisconnectedNode(DiscoveryNode discoveryNode) {
         }
     }
 
+    /**
+     * A fast response state.
+     *
+     * @opensearch.internal
+     */
     static class FastResponseState {
         final long term;
         final Mode mode;
@@ -309,6 +316,8 @@ public String toString() {
 
     /**
      * A checker for an individual follower.
+     *
+     * @opensearch.internal
      */
     private class FollowerChecker {
         private final DiscoveryNode discoveryNode;
@@ -447,6 +456,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Request to check follower.
+     *
+     * @opensearch.internal
+     */
     public static class FollowerCheckRequest extends TransportRequest {
 
         private final long term;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/InMemoryPersistedState.java b/server/src/main/java/org/opensearch/cluster/coordination/InMemoryPersistedState.java
index d9c10f7fe0af9..67ef82ee7b2e9 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/InMemoryPersistedState.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/InMemoryPersistedState.java
@@ -33,6 +33,11 @@
 
 import org.opensearch.cluster.ClusterState;
 
+/**
+ * Persist state in memory
+ *
+ * @opensearch.internal
+ */
 public class InMemoryPersistedState implements CoordinationState.PersistedState {
 
     private long currentTerm;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/Join.java b/server/src/main/java/org/opensearch/cluster/coordination/Join.java
index 50225c70620c5..58fa85992ebc8 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/Join.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/Join.java
@@ -32,9 +32,9 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -46,6 +46,8 @@
  * information about the current state of the node that provided the vote, so that
  * the receiver of the vote can determine if it has a more up-to-date state than the
  * source node.
+ *
+ * @opensearch.internal
  */
 public class Join implements Writeable {
     private final DiscoveryNode sourceNode;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/JoinHelper.java b/server/src/main/java/org/opensearch/cluster/coordination/JoinHelper.java
index 6d2fb99e04f86..0976d15c2a96b 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/JoinHelper.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/JoinHelper.java
@@ -35,34 +35,41 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
+import org.opensearch.Version;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskConfig;
 import org.opensearch.cluster.ClusterStateTaskListener;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.coordination.Coordinator.Mode;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.allocation.AllocationService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
+import org.opensearch.transport.BytesTransportRequest;
+import org.opensearch.transport.RemoteTransportException;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -78,18 +85,25 @@
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.LongSupplier;
 import java.util.function.Supplier;
 
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Helper utility class for joining the cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinHelper {
 
     private static final Logger logger = LogManager.getLogger(JoinHelper.class);
 
     public static final String JOIN_ACTION_NAME = "internal:cluster/coordination/join";
     public static final String VALIDATE_JOIN_ACTION_NAME = "internal:cluster/coordination/join/validate";
+    public static final String VALIDATE_COMPRESSED_JOIN_ACTION_NAME = JOIN_ACTION_NAME + "/validate_compressed";
     public static final String START_JOIN_ACTION_NAME = "internal:cluster/coordination/start_join";
 
     // the timeout for Zen1 join attempts
@@ -101,7 +115,7 @@ public class JoinHelper {
         Setting.Property.Deprecated
     );
 
-    private final MasterService masterService;
+    private final ClusterManagerService clusterManagerService;
     private final TransportService transportService;
     private volatile JoinTaskExecutor joinTaskExecutor;
 
@@ -113,49 +127,74 @@ public class JoinHelper {
     private final AtomicReference<FailedJoinAttempt> lastFailedJoinAttempt = new AtomicReference<>();
 
     private final Supplier<JoinTaskExecutor> joinTaskExecutorGenerator;
+    private final Consumer<Boolean> nodeCommissioned;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final AtomicReference<Tuple<Long, BytesReference>> serializedState = new AtomicReference<>();
 
     JoinHelper(
         Settings settings,
         AllocationService allocationService,
-        MasterService masterService,
+        ClusterManagerService clusterManagerService,
         TransportService transportService,
+        RemoteStoreNodeService remoteStoreNodeService,
         LongSupplier currentTermSupplier,
         Supplier<ClusterState> currentStateSupplier,
         BiConsumer<JoinRequest, JoinCallback> joinHandler,
         Function<StartJoinRequest, Join> joinLeaderInTerm,
         Collection<BiConsumer<DiscoveryNode, ClusterState>> joinValidators,
         RerouteService rerouteService,
-        NodeHealthService nodeHealthService
+        NodeHealthService nodeHealthService,
+        Consumer<Boolean> nodeCommissioned,
+        NamedWriteableRegistry namedWriteableRegistry
     ) {
-        this.masterService = masterService;
+        this.clusterManagerService = clusterManagerService;
         this.transportService = transportService;
         this.nodeHealthService = nodeHealthService;
         this.joinTimeout = JOIN_TIMEOUT_SETTING.get(settings);
-        this.joinTaskExecutorGenerator = () -> new JoinTaskExecutor(settings, allocationService, logger, rerouteService, transportService) {
+        this.nodeCommissioned = nodeCommissioned;
+        this.namedWriteableRegistry = namedWriteableRegistry;
+
+        this.joinTaskExecutorGenerator = () -> new JoinTaskExecutor(
+            settings,
+            allocationService,
+            logger,
+            rerouteService,
+            transportService,
+            remoteStoreNodeService
+        ) {
 
             private final long term = currentTermSupplier.getAsLong();
 
             @Override
             public ClusterTasksResult<JoinTaskExecutor.Task> execute(ClusterState currentState, List<JoinTaskExecutor.Task> joiningTasks)
                 throws Exception {
-                // The current state that MasterService uses might have been updated by a (different) master in a higher term already
+                // The current state that ClusterManagerService uses might have been updated by a (different) cluster-manager
+                // in a higher term already
                 // Stop processing the current cluster state update, as there's no point in continuing to compute it as
                 // it will later be rejected by Coordinator.publish(...) anyhow
                 if (currentState.term() > term) {
-                    logger.trace("encountered higher term {} than current {}, there is a newer master", currentState.term(), term);
-                    throw new NotMasterException(
-                        "Higher term encountered (current: " + currentState.term() + " > used: " + term + "), there is a newer master"
+                    logger.trace("encountered higher term {} than current {}, there is a newer cluster-manager", currentState.term(), term);
+                    throw new NotClusterManagerException(
+                        "Higher term encountered (current: "
+                            + currentState.term()
+                            + " > used: "
+                            + term
+                            + "), there is a newer cluster-manager"
                     );
-                } else if (currentState.nodes().getMasterNodeId() == null && joiningTasks.stream().anyMatch(Task::isBecomeMasterTask)) {
-                    assert currentState.term() < term : "there should be at most one become master task per election (= by term)";
-                    final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder(currentState.coordinationMetadata())
-                        .term(term)
-                        .build();
-                    final Metadata metadata = Metadata.builder(currentState.metadata()).coordinationMetadata(coordinationMetadata).build();
-                    currentState = ClusterState.builder(currentState).metadata(metadata).build();
-                } else if (currentState.nodes().isLocalNodeElectedMaster()) {
-                    assert currentState.term() == term : "term should be stable for the same master";
-                }
+                } else if (currentState.nodes().getClusterManagerNodeId() == null
+                    && joiningTasks.stream().anyMatch(Task::isBecomeClusterManagerTask)) {
+                        assert currentState.term() < term
+                            : "there should be at most one become cluster-manager task per election (= by term)";
+                        final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder(currentState.coordinationMetadata())
+                            .term(term)
+                            .build();
+                        final Metadata metadata = Metadata.builder(currentState.metadata())
+                            .coordinationMetadata(coordinationMetadata)
+                            .build();
+                        currentState = ClusterState.builder(currentState).metadata(metadata).build();
+                    } else if (currentState.nodes().isLocalNodeElectedClusterManager()) {
+                        assert currentState.term() == term : "term should be stable for the same cluster-manager";
+                    }
                 return super.execute(currentState, joiningTasks);
             }
 
@@ -188,22 +227,52 @@ public ClusterTasksResult<JoinTaskExecutor.Task> execute(ClusterState currentSta
             ThreadPool.Names.GENERIC,
             ValidateJoinRequest::new,
             (request, channel, task) -> {
-                final ClusterState localState = currentStateSupplier.get();
-                if (localState.metadata().clusterUUIDCommitted()
-                    && localState.metadata().clusterUUID().equals(request.getState().metadata().clusterUUID()) == false) {
-                    throw new CoordinationStateRejectedException(
-                        "join validation on cluster state"
-                            + " with a different cluster uuid "
-                            + request.getState().metadata().clusterUUID()
-                            + " than local cluster uuid "
-                            + localState.metadata().clusterUUID()
-                            + ", rejecting"
-                    );
-                }
-                joinValidators.forEach(action -> action.accept(transportService.getLocalNode(), request.getState()));
+                runJoinValidators(currentStateSupplier, request.getState(), joinValidators);
                 channel.sendResponse(Empty.INSTANCE);
             }
         );
+
+        transportService.registerRequestHandler(
+            VALIDATE_COMPRESSED_JOIN_ACTION_NAME,
+            ThreadPool.Names.GENERIC,
+            BytesTransportRequest::new,
+            (request, channel, task) -> {
+                handleCompressedValidateJoinRequest(currentStateSupplier, joinValidators, request);
+                channel.sendResponse(Empty.INSTANCE);
+            }
+        );
+
+    }
+
+    private void runJoinValidators(
+        Supplier<ClusterState> currentStateSupplier,
+        ClusterState incomingState,
+        Collection<BiConsumer<DiscoveryNode, ClusterState>> joinValidators
+    ) {
+        final ClusterState localState = currentStateSupplier.get();
+        if (localState.metadata().clusterUUIDCommitted()
+            && localState.metadata().clusterUUID().equals(incomingState.metadata().clusterUUID()) == false) {
+            throw new CoordinationStateRejectedException(
+                "join validation on cluster state"
+                    + " with a different cluster uuid "
+                    + incomingState.metadata().clusterUUID()
+                    + " than local cluster uuid "
+                    + localState.metadata().clusterUUID()
+                    + ", rejecting"
+            );
+        }
+        joinValidators.forEach(action -> action.accept(transportService.getLocalNode(), incomingState));
+    }
+
+    private void handleCompressedValidateJoinRequest(
+        Supplier<ClusterState> currentStateSupplier,
+        Collection<BiConsumer<DiscoveryNode, ClusterState>> joinValidators,
+        BytesTransportRequest request
+    ) throws IOException {
+        try (StreamInput input = CompressedStreamUtils.decompressBytes(request, namedWriteableRegistry)) {
+            ClusterState incomingState = ClusterState.readFrom(input, transportService.getLocalNode());
+            runJoinValidators(currentStateSupplier, incomingState, joinValidators);
+        }
     }
 
     private JoinCallback transportJoinCallback(TransportRequest request, TransportChannel channel) {
@@ -243,6 +312,11 @@ public void sendJoinRequest(DiscoveryNode destination, long term, Optional<Join>
         sendJoinRequest(destination, term, optionalJoin, () -> {});
     }
 
+    /**
+     * A failed join attempt.
+     *
+     * @opensearch.internal
+     */
     // package-private for testing
     static class FailedJoinAttempt {
         private final DiscoveryNode destination;
@@ -269,7 +343,7 @@ static Level getLogLevel(TransportException e) {
             Throwable cause = e.unwrapCause();
             if (cause instanceof CoordinationStateRejectedException
                 || cause instanceof FailedToCommitClusterStateException
-                || cause instanceof NotMasterException) {
+                || cause instanceof NotClusterManagerException) {
                 return Level.DEBUG;
             }
             return Level.INFO;
@@ -297,7 +371,7 @@ void logLastFailedJoinAttempt() {
     }
 
     public void sendJoinRequest(DiscoveryNode destination, long term, Optional<Join> optionalJoin, Runnable onCompletion) {
-        assert destination.isMasterNode() : "trying to join master-ineligible " + destination;
+        assert destination.isClusterManagerNode() : "trying to join cluster-manager-ineligible " + destination;
         final StatusInfo statusInfo = nodeHealthService.getHealth();
         if (statusInfo.getStatus() == UNHEALTHY) {
             logger.debug("dropping join request to [{}]: [{}]", destination, statusInfo.getInfo());
@@ -323,6 +397,7 @@ public void handleResponse(Empty response) {
                         pendingOutgoingJoins.remove(dedupKey);
                         logger.debug("successfully joined {} with {}", destination, joinRequest);
                         lastFailedJoinAttempt.set(null);
+                        nodeCommissioned.accept(true);
                         onCompletion.run();
                     }
 
@@ -333,6 +408,13 @@ public void handleException(TransportException exp) {
                         FailedJoinAttempt attempt = new FailedJoinAttempt(destination, joinRequest, exp);
                         attempt.logNow();
                         lastFailedJoinAttempt.set(attempt);
+                        if (exp instanceof RemoteTransportException && (exp.getCause() instanceof NodeDecommissionedException)) {
+                            logger.info(
+                                "local node is decommissioned [{}]. Will not be able to join the cluster",
+                                exp.getCause().getMessage()
+                            );
+                            nodeCommissioned.accept(false);
+                        }
                         onCompletion.run();
                     }
 
@@ -348,7 +430,7 @@ public String executor() {
     }
 
     public void sendStartJoinRequest(final StartJoinRequest startJoinRequest, final DiscoveryNode destination) {
-        assert startJoinRequest.getSourceNode().isMasterNode() : "sending start-join request for master-ineligible "
+        assert startJoinRequest.getSourceNode().isClusterManagerNode() : "sending start-join request for cluster-manager-ineligible "
             + startJoinRequest.getSourceNode();
         transportService.sendRequest(destination, START_JOIN_ACTION_NAME, startJoinRequest, new TransportResponseHandler<Empty>() {
             @Override
@@ -374,20 +456,60 @@ public String executor() {
     }
 
     public void sendValidateJoinRequest(DiscoveryNode node, ClusterState state, ActionListener<TransportResponse.Empty> listener) {
-        transportService.sendRequest(
-            node,
-            VALIDATE_JOIN_ACTION_NAME,
-            new ValidateJoinRequest(state),
-            new ActionListenerResponseHandler<>(listener, i -> Empty.INSTANCE, ThreadPool.Names.GENERIC)
-        );
+        if (node.getVersion().before(Version.V_2_9_0)) {
+            transportService.sendRequest(
+                node,
+                VALIDATE_JOIN_ACTION_NAME,
+                new ValidateJoinRequest(state),
+                new ActionListenerResponseHandler<>(listener, i -> Empty.INSTANCE, ThreadPool.Names.GENERIC)
+            );
+        } else {
+            try {
+                final BytesReference bytes = serializedState.updateAndGet(cachedState -> {
+                    if (cachedState == null || cachedState.v1() != state.version()) {
+                        try {
+                            return new Tuple<>(
+                                state.version(),
+                                CompressedStreamUtils.createCompressedStream(node.getVersion(), state::writeTo)
+                            );
+                        } catch (IOException e) {
+                            // mandatory as AtomicReference doesn't rethrow IOException.
+                            throw new RuntimeException(e);
+                        }
+                    } else {
+                        return cachedState;
+                    }
+                }).v2();
+                final BytesTransportRequest request = new BytesTransportRequest(bytes, node.getVersion());
+                transportService.sendRequest(
+                    node,
+                    VALIDATE_COMPRESSED_JOIN_ACTION_NAME,
+                    request,
+                    new ActionListenerResponseHandler<>(listener, i -> Empty.INSTANCE, ThreadPool.Names.GENERIC)
+                );
+            } catch (Exception e) {
+                logger.warn("error sending cluster state to {}", node);
+                listener.onFailure(e);
+            }
+        }
     }
 
+    /**
+     * The callback interface.
+     *
+     * @opensearch.internal
+     */
     public interface JoinCallback {
         void onSuccess();
 
         void onFailure(Exception e);
     }
 
+    /**
+     * Listener for the join task
+     *
+     * @opensearch.internal
+     */
     static class JoinTaskListener implements ClusterStateTaskListener {
         private final JoinTaskExecutor.Task task;
         private final JoinCallback joinCallback;
@@ -419,12 +541,17 @@ interface JoinAccumulator {
         default void close(Mode newMode) {}
     }
 
+    /**
+     * A leader join accumulator.
+     *
+     * @opensearch.internal
+     */
     class LeaderJoinAccumulator implements JoinAccumulator {
         @Override
         public void handleJoinRequest(DiscoveryNode sender, JoinCallback joinCallback) {
             final JoinTaskExecutor.Task task = new JoinTaskExecutor.Task(sender, "join existing leader");
             assert joinTaskExecutor != null;
-            masterService.submitStateUpdateTask(
+            clusterManagerService.submitStateUpdateTask(
                 "node-join",
                 task,
                 ClusterStateTaskConfig.build(Priority.URGENT),
@@ -439,6 +566,11 @@ public String toString() {
         }
     }
 
+    /**
+     * An initial join accumulator.
+     *
+     * @opensearch.internal
+     */
     static class InitialJoinAccumulator implements JoinAccumulator {
         @Override
         public void handleJoinRequest(DiscoveryNode sender, JoinCallback joinCallback) {
@@ -452,6 +584,11 @@ public String toString() {
         }
     }
 
+    /**
+     * A follower join accumulator.
+     *
+     * @opensearch.internal
+     */
     static class FollowerJoinAccumulator implements JoinAccumulator {
         @Override
         public void handleJoinRequest(DiscoveryNode sender, JoinCallback joinCallback) {
@@ -464,6 +601,11 @@ public String toString() {
         }
     }
 
+    /**
+     * A candidate join accumulator.
+     *
+     * @opensearch.internal
+     */
     class CandidateJoinAccumulator implements JoinAccumulator {
 
         private final Map<DiscoveryNode, JoinCallback> joinRequestAccumulator = new HashMap<>();
@@ -489,12 +631,12 @@ public void close(Mode newMode) {
                     pendingAsTasks.put(task, new JoinTaskListener(task, value));
                 });
 
-                final String stateUpdateSource = "elected-as-master ([" + pendingAsTasks.size() + "] nodes joined)";
+                final String stateUpdateSource = "elected-as-cluster-manager ([" + pendingAsTasks.size() + "] nodes joined)";
 
-                pendingAsTasks.put(JoinTaskExecutor.newBecomeMasterTask(), (source, e) -> {});
+                pendingAsTasks.put(JoinTaskExecutor.newBecomeClusterManagerTask(), (source, e) -> {});
                 pendingAsTasks.put(JoinTaskExecutor.newFinishElectionTask(), (source, e) -> {});
                 joinTaskExecutor = joinTaskExecutorGenerator.get();
-                masterService.submitStateUpdateTasks(
+                clusterManagerService.submitStateUpdateTasks(
                     stateUpdateSource,
                     pendingAsTasks,
                     ClusterStateTaskConfig.build(Priority.URGENT),
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/JoinRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/JoinRequest.java
index f18396e78fbf9..6eb1514ae848c 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/JoinRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/JoinRequest.java
@@ -33,14 +33,19 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+/**
+ * Request for a node to join the cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinRequest extends TransportRequest {
 
     /**
@@ -50,15 +55,15 @@ public class JoinRequest extends TransportRequest {
 
     /**
      * The minimum term for which the joining node will accept any cluster state publications. If the joining node is in a strictly greater
-     * term than the master it wants to join then the master must enter a new term and hold another election. Doesn't necessarily match
+     * term than the cluster-manager it wants to join then the cluster-manager must enter a new term and hold another election. Doesn't necessarily match
      * {@link JoinRequest#optionalJoin} and may be zero in join requests sent prior to {@link LegacyESVersion#V_7_7_0}.
      */
     private final long minimumTerm;
 
     /**
-     * A vote for the receiving node. This vote is optional since the sending node may have voted for a different master in this term.
-     * That's ok, the sender likely discovered that the master we voted for lost the election and now we're trying to join the winner. Once
-     * the sender has successfully joined the master, the lack of a vote in its term causes another election (see
+     * A vote for the receiving node. This vote is optional since the sending node may have voted for a different cluster-manager in this term.
+     * That's ok, the sender likely discovered that the cluster-manager we voted for lost the election and now we're trying to join the winner. Once
+     * the sender has successfully joined the cluster-manager, the lack of a vote in its term causes another election (see
      * {@link Publication#onMissingJoin(DiscoveryNode)}).
      */
     private final Optional<Join> optionalJoin;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/JoinTaskExecutor.java b/server/src/main/java/org/opensearch/cluster/coordination/JoinTaskExecutor.java
index ea5c33b4300a5..a7b96d6a3e0f8 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/JoinTaskExecutor.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/JoinTaskExecutor.java
@@ -34,19 +34,23 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.block.ClusterBlocks;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.node.remotestore.RemoteStoreNodeAttribute;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.persistent.PersistentTasksCustomMetadata;
 import org.opensearch.transport.TransportService;
 
@@ -60,8 +64,17 @@
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
+import static org.opensearch.cluster.decommission.DecommissionHelper.nodeCommissioned;
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.CompatibilityMode;
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.CompatibilityMode.STRICT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING;
 
+/**
+ * Main executor for Nodes joining the OpenSearch cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinTaskExecutor implements ClusterStateTaskExecutor<JoinTaskExecutor.Task> {
 
     private final AllocationService allocationService;
@@ -70,6 +83,13 @@ public class JoinTaskExecutor implements ClusterStateTaskExecutor<JoinTaskExecut
     private final RerouteService rerouteService;
     private final TransportService transportService;
 
+    private final RemoteStoreNodeService remoteStoreNodeService;
+
+    /**
+     * Task for the join task executor.
+     *
+     * @opensearch.internal
+     */
     public static class Task {
 
         private final DiscoveryNode node;
@@ -93,15 +113,26 @@ public String toString() {
             return node != null ? node + " " + reason : reason;
         }
 
+        public boolean isBecomeClusterManagerTask() {
+            return reason.equals(BECOME_MASTER_TASK_REASON) || reason.equals(BECOME_CLUSTER_MANAGER_TASK_REASON);
+        }
+
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isBecomeClusterManagerTask()} */
+        @Deprecated
         public boolean isBecomeMasterTask() {
-            return reason.equals(BECOME_MASTER_TASK_REASON);
+            return isBecomeClusterManagerTask();
         }
 
         public boolean isFinishElectionTask() {
             return reason.equals(FINISH_ELECTION_TASK_REASON);
         }
 
+        /**
+         * @deprecated As of 2.0, because supporting inclusive language, replaced by {@link #BECOME_CLUSTER_MANAGER_TASK_REASON}
+         */
+        @Deprecated
         private static final String BECOME_MASTER_TASK_REASON = "_BECOME_MASTER_TASK_";
+        private static final String BECOME_CLUSTER_MANAGER_TASK_REASON = "_BECOME_CLUSTER_MANAGER_TASK_";
         private static final String FINISH_ELECTION_TASK_REASON = "_FINISH_ELECTION_";
     }
 
@@ -110,12 +141,14 @@ public JoinTaskExecutor(
         AllocationService allocationService,
         Logger logger,
         RerouteService rerouteService,
-        TransportService transportService
+        TransportService transportService,
+        RemoteStoreNodeService remoteStoreNodeService
     ) {
         this.allocationService = allocationService;
         this.logger = logger;
         this.rerouteService = rerouteService;
         this.transportService = transportService;
+        this.remoteStoreNodeService = remoteStoreNodeService;
     }
 
     @Override
@@ -128,24 +161,36 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
 
         if (joiningNodes.size() == 1 && joiningNodes.get(0).isFinishElectionTask()) {
             return results.successes(joiningNodes).build(currentState);
-        } else if (currentNodes.getMasterNode() == null && joiningNodes.stream().anyMatch(Task::isBecomeMasterTask)) {
-            assert joiningNodes.stream().anyMatch(Task::isFinishElectionTask) : "becoming a master but election is not finished "
+        } else if (currentNodes.getClusterManagerNode() == null && joiningNodes.stream().anyMatch(Task::isBecomeClusterManagerTask)) {
+            assert joiningNodes.stream().anyMatch(Task::isFinishElectionTask) : "becoming a cluster-manager but election is not finished "
                 + joiningNodes;
-            // use these joins to try and become the master.
+            // use these joins to try and become the cluster-manager.
             // Note that we don't have to do any validation of the amount of joining nodes - the commit
             // during the cluster state publishing guarantees that we have enough
-            newState = becomeMasterAndTrimConflictingNodes(currentState, joiningNodes);
+            newState = becomeClusterManagerAndTrimConflictingNodes(currentState, joiningNodes);
             nodesChanged = true;
-        } else if (currentNodes.isLocalNodeElectedMaster() == false) {
-            logger.trace("processing node joins, but we are not the master. current master: {}", currentNodes.getMasterNode());
-            throw new NotMasterException("Node [" + currentNodes.getLocalNode() + "] not master for join request");
+        } else if (currentNodes.isLocalNodeElectedClusterManager() == false) {
+            logger.trace(
+                "processing node joins, but we are not the cluster-manager. current cluster-manager: {}",
+                currentNodes.getClusterManagerNode()
+            );
+            throw new NotClusterManagerException("Node [" + currentNodes.getLocalNode() + "] not cluster-manager for join request");
         } else {
             newState = ClusterState.builder(currentState);
         }
 
         DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(newState.nodes());
 
-        assert nodesBuilder.isLocalNodeElectedMaster();
+        // TODO: We are using one of the existing node to build the repository metadata, this will need to be updated
+        // once we start supporting mixed compatibility mode. An optimization can be done as this will get invoked
+        // for every set of node join task which we can optimize to not compute if cluster state already has
+        // repository information.
+        RepositoriesMetadata repositoriesMetadata = remoteStoreNodeService.updateRepositoriesMetadata(
+            (currentNodes.getNodes().values()).stream().findFirst().get(),
+            currentState.getMetadata().custom(RepositoriesMetadata.TYPE)
+        );
+
+        assert nodesBuilder.isLocalNodeElectedClusterManager();
 
         Version minClusterNodeVersion = newState.nodes().getMinNodeVersion();
         Version maxClusterNodeVersion = newState.nodes().getMaxNodeVersion();
@@ -154,7 +199,7 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
         // processing any joins
         Map<String, String> joiniedNodeNameIds = new HashMap<>();
         for (final Task joinTask : joiningNodes) {
-            if (joinTask.isBecomeMasterTask() || joinTask.isFinishElectionTask()) {
+            if (joinTask.isBecomeClusterManagerTask() || joinTask.isFinishElectionTask()) {
                 // noop
             } else if (currentNodes.nodeExistsWithSameRoles(joinTask.node()) && !currentNodes.nodeExistsWithBWCVersion(joinTask.node())) {
                 logger.debug("received a join request for an existing node [{}]", joinTask.node());
@@ -164,18 +209,21 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
                     if (enforceMajorVersion) {
                         ensureMajorVersionBarrier(node.getVersion(), minClusterNodeVersion);
                     }
-                    ensureNodesCompatibility(node.getVersion(), minClusterNodeVersion, maxClusterNodeVersion);
+                    ensureNodesCompatibility(node, currentNodes, currentState.metadata(), minClusterNodeVersion, maxClusterNodeVersion);
                     // we do this validation quite late to prevent race conditions between nodes joining and importing dangling indices
                     // we have to reject nodes that don't support all indices we have in this cluster
                     ensureIndexCompatibility(node.getVersion(), currentState.getMetadata());
+                    // we have added the same check in handleJoinRequest method and adding it here as this method
+                    // would guarantee that a decommissioned node would never be able to join the cluster and ensures correctness
+                    ensureNodeCommissioned(node, currentState.metadata());
                     nodesBuilder.add(node);
                     nodesChanged = true;
                     minClusterNodeVersion = Version.min(minClusterNodeVersion, node.getVersion());
                     maxClusterNodeVersion = Version.max(maxClusterNodeVersion, node.getVersion());
-                    if (node.isMasterNode()) {
+                    if (node.isClusterManagerNode()) {
                         joiniedNodeNameIds.put(node.getName(), node.getId());
                     }
-                } catch (IllegalArgumentException | IllegalStateException e) {
+                } catch (IllegalArgumentException | IllegalStateException | NodeDecommissionedException e) {
                     results.failure(joinTask, e);
                     continue;
                 }
@@ -213,27 +261,47 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
                         .coordinationMetadata(coordMetadataBuilder.build())
                         .build();
                     return results.build(
-                        allocationService.adaptAutoExpandReplicas(newState.nodes(nodesBuilder).metadata(newMetadata).build())
+                        allocationService.adaptAutoExpandReplicas(
+                            newState.nodes(nodesBuilder)
+                                .metadata(updateMetadataWithRepositoriesMetadata(newMetadata, repositoriesMetadata))
+                                .build()
+                        )
                     );
                 }
             }
 
-            return results.build(allocationService.adaptAutoExpandReplicas(newState.nodes(nodesBuilder).build()));
+            return results.build(
+                allocationService.adaptAutoExpandReplicas(
+                    newState.nodes(nodesBuilder)
+                        .metadata(updateMetadataWithRepositoriesMetadata(currentState.metadata(), repositoriesMetadata))
+                        .build()
+                )
+            );
         } else {
             // we must return a new cluster state instance to force publishing. This is important
-            // for the joining node to finalize its join and set us as a master
-            return results.build(newState.build());
+            // for the joining node to finalize its join and set us as a cluster-manager
+            return results.build(
+                newState.metadata(updateMetadataWithRepositoriesMetadata(currentState.metadata(), repositoriesMetadata)).build()
+            );
+        }
+    }
+
+    private Metadata updateMetadataWithRepositoriesMetadata(Metadata currentMetadata, RepositoriesMetadata repositoriesMetadata) {
+        if (repositoriesMetadata == null || repositoriesMetadata.repositories() == null || repositoriesMetadata.repositories().isEmpty()) {
+            return currentMetadata;
+        } else {
+            return Metadata.builder(currentMetadata).putCustom(RepositoriesMetadata.TYPE, repositoriesMetadata.get()).build();
         }
     }
 
-    protected ClusterState.Builder becomeMasterAndTrimConflictingNodes(ClusterState currentState, List<Task> joiningNodes) {
-        assert currentState.nodes().getMasterNodeId() == null : currentState;
+    protected ClusterState.Builder becomeClusterManagerAndTrimConflictingNodes(ClusterState currentState, List<Task> joiningNodes) {
+        assert currentState.nodes().getClusterManagerNodeId() == null : currentState;
         DiscoveryNodes currentNodes = currentState.nodes();
         DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(currentNodes);
-        nodesBuilder.masterNodeId(currentState.nodes().getLocalNodeId());
+        nodesBuilder.clusterManagerNodeId(currentState.nodes().getLocalNodeId());
 
         for (final Task joinTask : joiningNodes) {
-            if (joinTask.isBecomeMasterTask()) {
+            if (joinTask.isBecomeClusterManagerTask()) {
                 refreshDiscoveryNodeVersionAfterUpgrade(currentNodes, nodesBuilder);
             } else if (joinTask.isFinishElectionTask()) {
                 // no-op
@@ -256,13 +324,17 @@ protected ClusterState.Builder becomeMasterAndTrimConflictingNodes(ClusterState
             }
         }
 
-        // now trim any left over dead nodes - either left there when the previous master stepped down
+        // now trim any left over dead nodes - either left there when the previous cluster-manager stepped down
         // or removed by us above
         ClusterState tmpState = ClusterState.builder(currentState)
             .nodes(nodesBuilder)
-            .blocks(ClusterBlocks.builder().blocks(currentState.blocks()).removeGlobalBlock(NoMasterBlockService.NO_MASTER_BLOCK_ID))
+            .blocks(
+                ClusterBlocks.builder()
+                    .blocks(currentState.blocks())
+                    .removeGlobalBlock(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID)
+            )
             .build();
-        logger.trace("becomeMasterAndTrimConflictingNodes: {}", tmpState.nodes());
+        logger.trace("becomeClusterManagerAndTrimConflictingNodes: {}", tmpState.nodes());
         allocationService.cleanCaches();
         tmpState = PersistentTasksCustomMetadata.disassociateDeadNodes(tmpState);
         return ClusterState.builder(allocationService.disassociateDeadNodes(tmpState, false, "removed dead nodes on election"));
@@ -277,7 +349,7 @@ private void refreshDiscoveryNodeVersionAfterUpgrade(DiscoveryNodes currentNodes
         // updating the version of those node which have connection with the new master.
         // Note: This should get deprecated with BWC mode logic
         if (null == transportService) {
-            // this logic is only applicable when OpenSearch node is master and is noop for zen discovery node
+            // this logic is only applicable when OpenSearch node is cluster-manager and is noop for zen discovery node
             return;
         }
         if (currentNodes.getMinNodeVersion().before(Version.V_1_0_0)) {
@@ -310,7 +382,7 @@ private void refreshDiscoveryNodeVersionAfterUpgrade(DiscoveryNodes currentNodes
                     }
                 } else {
                     // in case existing OpenSearch node is present in the cluster and but there is no connection to that node yet,
-                    // either that node will send new JoinRequest to the master with version >=1.0, then no issue or
+                    // either that node will send new JoinRequest to the cluster-manager/master with version >=1.0, then no issue or
                     // there is an edge case if doesn't send JoinRequest and connection is established,
                     // then it can continue to report version as 7.10.2 instead of actual OpenSearch version. So,
                     // removing the node from cluster state to prevent stale version reporting and let it reconnect.
@@ -323,18 +395,31 @@ private void refreshDiscoveryNodeVersionAfterUpgrade(DiscoveryNodes currentNodes
     }
 
     @Override
-    public boolean runOnlyOnMaster() {
+    public boolean runOnlyOnClusterManager() {
         // we validate that we are allowed to change the cluster state during cluster state processing
         return false;
     }
 
+    /**
+     * a task indicates that the current node should become master
+     *
+     * @deprecated As of 2.0, because supporting inclusive language, replaced by {@link #newBecomeClusterManagerTask()}
+     */
+    @Deprecated
     public static Task newBecomeMasterTask() {
         return new Task(null, Task.BECOME_MASTER_TASK_REASON);
     }
 
+    /**
+     * a task indicates that the current node should become cluster-manager
+     */
+    public static Task newBecomeClusterManagerTask() {
+        return new Task(null, Task.BECOME_CLUSTER_MANAGER_TASK_REASON);
+    }
+
     /**
      * a task that is used to signal the election is stopped and we should process pending joins.
-     * it may be used in combination with {@link JoinTaskExecutor#newBecomeMasterTask()}
+     * it may be used in combination with {@link JoinTaskExecutor#newBecomeClusterManagerTask()}
      */
     public static Task newFinishElectionTask() {
         return new Task(null, Task.FINISH_ELECTION_TASK_REASON);
@@ -344,8 +429,9 @@ public static Task newFinishElectionTask() {
      * Ensures that all indices are compatible with the given node version. This will ensure that all indices in the given metadata
      * will not be created with a newer version of opensearch as well as that all indices are newer or equal to the minimum index
      * compatibility version.
-     * @see Version#minimumIndexCompatibilityVersion()
+     *
      * @throws IllegalStateException if any index is incompatible with the given version
+     * @see Version#minimumIndexCompatibilityVersion()
      */
     public static void ensureIndexCompatibility(final Version nodeVersion, Metadata metadata) {
         Version supportedIndexVersion = nodeVersion.minimumIndexCompatibilityVersion();
@@ -375,15 +461,27 @@ public static void ensureIndexCompatibility(final Version nodeVersion, Metadata
         }
     }
 
-    /** ensures that the joining node has a version that's compatible with all current nodes*/
-    public static void ensureNodesCompatibility(final Version joiningNodeVersion, DiscoveryNodes currentNodes) {
+    /**
+     * ensures that the joining node has a version that's compatible with all current nodes
+     */
+    public static void ensureNodesCompatibility(final DiscoveryNode joiningNode, DiscoveryNodes currentNodes, Metadata metadata) {
         final Version minNodeVersion = currentNodes.getMinNodeVersion();
         final Version maxNodeVersion = currentNodes.getMaxNodeVersion();
-        ensureNodesCompatibility(joiningNodeVersion, minNodeVersion, maxNodeVersion);
+        ensureNodesCompatibility(joiningNode, currentNodes, metadata, minNodeVersion, maxNodeVersion);
     }
 
-    /** ensures that the joining node has a version that's compatible with a given version range */
-    public static void ensureNodesCompatibility(Version joiningNodeVersion, Version minClusterNodeVersion, Version maxClusterNodeVersion) {
+    /**
+     * ensures that the joining node has a version that's compatible with a given version range and ensures that the
+     * joining node has required attributes to join a remotestore cluster.
+     */
+    public static void ensureNodesCompatibility(
+        DiscoveryNode joiningNode,
+        DiscoveryNodes currentNodes,
+        Metadata metadata,
+        Version minClusterNodeVersion,
+        Version maxClusterNodeVersion
+    ) {
+        Version joiningNodeVersion = joiningNode.getVersion();
         assert minClusterNodeVersion.onOrBefore(maxClusterNodeVersion) : minClusterNodeVersion + " > " + maxClusterNodeVersion;
         if (joiningNodeVersion.isCompatible(maxClusterNodeVersion) == false) {
             throw new IllegalStateException(
@@ -405,11 +503,13 @@ public static void ensureNodesCompatibility(Version joiningNodeVersion, Version
                     + "], which is incompatible."
             );
         }
+
+        ensureRemoteStoreNodesCompatibility(joiningNode, currentNodes, metadata);
     }
 
     /**
      * ensures that the joining node's major version is equal or higher to the minClusterNodeVersion. This is needed
-     * to ensure that if the master is already fully operating under the new major version, it doesn't go back to mixed
+     * to ensure that if the cluster-manager/master is already fully operating under the new major version, it doesn't go back to mixed
      * version mode
      **/
     public static void ensureMajorVersionBarrier(Version joiningNodeVersion, Version minClusterNodeVersion) {
@@ -426,13 +526,78 @@ public static void ensureMajorVersionBarrier(Version joiningNodeVersion, Version
         }
     }
 
+    public static void ensureNodeCommissioned(DiscoveryNode node, Metadata metadata) {
+        if (nodeCommissioned(node, metadata) == false) {
+            throw new NodeDecommissionedException(
+                "node [{}] has decommissioned attribute [{}] with current status of decommissioning [{}]",
+                node.toString(),
+                metadata.decommissionAttributeMetadata().decommissionAttribute().toString(),
+                metadata.decommissionAttributeMetadata().status().status()
+            );
+        }
+    }
+
+    /**
+     * The method ensures homogeneity -
+     * 1. The joining node has to be a remote store backed if it's joining a remote store backed cluster. Validates
+     * remote store attributes of joining node against the existing nodes of cluster.
+     * 2. The joining node has to be a non-remote store backed if it is joining a non-remote store backed cluster.
+     * Validates no remote store attributes are present in joining node as existing nodes in the cluster doesn't have
+     * remote store attributes.
+     *
+     * A remote store backed node is the one which holds all the remote store attributes and a remote store backed
+     * cluster is the one which has only homogeneous remote store backed nodes with same node attributes
+     *
+     * TODO: When we support moving from remote store cluster to non remote store and vice versa the this logic will
+     *       needs to be modified.
+     */
+    private static void ensureRemoteStoreNodesCompatibility(DiscoveryNode joiningNode, DiscoveryNodes currentNodes, Metadata metadata) {
+        List<DiscoveryNode> existingNodes = new ArrayList<>(currentNodes.getNodes().values());
+
+        assert existingNodes.isEmpty() == false;
+
+        // TODO: The below check is valid till we don't support migration, once we start supporting migration a remote
+        // store node will be able to join a non remote store cluster and vice versa. #7986
+        CompatibilityMode remoteStoreCompatibilityMode = REMOTE_STORE_COMPATIBILITY_MODE_SETTING.get(metadata.settings());
+        if (STRICT.equals(remoteStoreCompatibilityMode)) {
+            DiscoveryNode existingNode = existingNodes.get(0);
+            if (joiningNode.isRemoteStoreNode()) {
+                if (existingNode.isRemoteStoreNode()) {
+                    RemoteStoreNodeAttribute joiningRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(joiningNode);
+                    RemoteStoreNodeAttribute existingRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(existingNode);
+                    if (existingRemoteStoreNodeAttribute.equals(joiningRemoteStoreNodeAttribute) == false) {
+                        throw new IllegalStateException(
+                            "a remote store node ["
+                                + joiningNode
+                                + "] is trying to join a remote store cluster with incompatible node attributes in "
+                                + "comparison with existing node ["
+                                + existingNode
+                                + "]"
+                        );
+                    }
+                } else {
+                    throw new IllegalStateException(
+                        "a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"
+                    );
+                }
+            } else {
+                if (existingNode.isRemoteStoreNode()) {
+                    throw new IllegalStateException(
+                        "a non remote store node [" + joiningNode + "] is trying to join a remote store cluster"
+                    );
+                }
+            }
+        }
+    }
+
     public static Collection<BiConsumer<DiscoveryNode, ClusterState>> addBuiltInJoinValidators(
         Collection<BiConsumer<DiscoveryNode, ClusterState>> onJoinValidators
     ) {
         final Collection<BiConsumer<DiscoveryNode, ClusterState>> validators = new ArrayList<>();
         validators.add((node, state) -> {
-            ensureNodesCompatibility(node.getVersion(), state.getNodes());
+            ensureNodesCompatibility(node, state.getNodes(), state.metadata());
             ensureIndexCompatibility(node.getVersion(), state.getMetadata());
+            ensureNodeCommissioned(node, state.getMetadata());
         });
         validators.addAll(onJoinValidators);
         return Collections.unmodifiableCollection(validators);
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/LagDetector.java b/server/src/main/java/org/opensearch/cluster/coordination/LagDetector.java
index e599fffa68ff1..eeb0800663d0a 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/LagDetector.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/LagDetector.java
@@ -56,6 +56,8 @@
  * A publication can succeed and complete before all nodes have applied the published state and acknowledged it; however we need every node
  * eventually either to apply the published state (or a later state) or be removed from the cluster. This component achieves this by
  * removing any lagging nodes from the cluster after a timeout.
+ *
+ * @opensearch.internal
  */
 public class LagDetector {
 
@@ -102,7 +104,7 @@ public void clearTrackedNodes() {
     public void setAppliedVersion(final DiscoveryNode discoveryNode, final long appliedVersion) {
         final NodeAppliedStateTracker nodeAppliedStateTracker = appliedStateTrackersByNode.get(discoveryNode);
         if (nodeAppliedStateTracker == null) {
-            // Received an ack from a node that a later publication has removed (or we are no longer master). No big deal.
+            // Received an ack from a node that a later publication has removed (or we are no longer cluster-manager). No big deal.
             logger.trace("node {} applied version {} but this node's version is not being tracked", discoveryNode, appliedVersion);
         } else {
             nodeAppliedStateTracker.increaseAppliedVersion(appliedVersion);
@@ -149,6 +151,11 @@ Set<DiscoveryNode> getTrackedNodes() {
         return Collections.unmodifiableSet(appliedStateTrackersByNode.keySet());
     }
 
+    /**
+     * A tracker that the node applied state.
+     *
+     * @opensearch.internal
+     */
     private class NodeAppliedStateTracker {
         private final DiscoveryNode discoveryNode;
         private final AtomicLong appliedVersion = new AtomicLong();
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java b/server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java
index b4edc9401234d..69ba1f977f326 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java
@@ -39,12 +39,14 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.threadpool.ThreadPool.Names;
@@ -56,8 +58,6 @@
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportRequestOptions.Type;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -75,6 +75,8 @@
  * fairly lenient, possibly allowing multiple checks to fail before considering the leader to be faulty, to allow for the leader to
  * temporarily stand down on occasion, e.g. if it needs to move to a higher term. On deciding that the leader has failed a follower will
  * become a candidate and attempt to become a leader itself.
+ *
+ * @opensearch.internal
  */
 public class LeaderChecker {
 
@@ -190,8 +192,8 @@ void setCurrentNodes(DiscoveryNodes discoveryNodes) {
     }
 
     // For assertions
-    boolean currentNodeIsMaster() {
-        return discoveryNodes.isLocalNodeElectedMaster();
+    boolean currentNodeIsClusterManager() {
+        return discoveryNodes.isLocalNodeElectedClusterManager();
     }
 
     private void handleLeaderCheck(LeaderCheckRequest request) {
@@ -207,10 +209,10 @@ private void handleLeaderCheck(LeaderCheckRequest request) {
                 + "]";
             logger.debug(message);
             throw new NodeHealthCheckFailureException(message);
-        } else if (discoveryNodes.isLocalNodeElectedMaster() == false) {
-            logger.debug("rejecting leader check on non-master {}", request);
+        } else if (discoveryNodes.isLocalNodeElectedClusterManager() == false) {
+            logger.debug("rejecting leader check on non-cluster-manager {}", request);
             throw new CoordinationStateRejectedException(
-                "rejecting leader check from [" + request.getSender() + "] sent to a node that is no longer the master"
+                "rejecting leader check from [" + request.getSender() + "] sent to a node that is no longer the cluster-manager"
             );
         } else if (discoveryNodes.nodeExists(request.getSender()) == false) {
             logger.debug("rejecting leader check from removed node: {}", request);
@@ -231,6 +233,11 @@ private void handleDisconnectedNode(DiscoveryNode discoveryNode) {
         }
     }
 
+    /**
+     * A check scheduler.
+     *
+     * @opensearch.internal
+     */
     private class CheckScheduler implements Releasable {
 
         private final AtomicBoolean isClosed = new AtomicBoolean();
@@ -378,6 +385,11 @@ public String toString() {
         }
     }
 
+    /**
+     * A leader check request.
+     *
+     * @opensearch.internal
+     */
     static class LeaderCheckRequest extends TransportRequest {
 
         private final DiscoveryNode sender;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/NoClusterManagerBlockService.java b/server/src/main/java/org/opensearch/cluster/coordination/NoClusterManagerBlockService.java
new file mode 100644
index 0000000000000..b377fe592b0f4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/coordination/NoClusterManagerBlockService.java
@@ -0,0 +1,145 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.cluster.block.ClusterBlock;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
+
+import java.util.EnumSet;
+
+/**
+ * Service to block the master node
+ *
+ * @opensearch.internal
+ */
+public class NoClusterManagerBlockService {
+    public static final int NO_CLUSTER_MANAGER_BLOCK_ID = 2;
+    public static final ClusterBlock NO_CLUSTER_MANAGER_BLOCK_WRITES = new ClusterBlock(
+        NO_CLUSTER_MANAGER_BLOCK_ID,
+        "no cluster-manager",
+        true,
+        false,
+        false,
+        RestStatus.SERVICE_UNAVAILABLE,
+        EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE)
+    );
+    public static final ClusterBlock NO_CLUSTER_MANAGER_BLOCK_ALL = new ClusterBlock(
+        NO_CLUSTER_MANAGER_BLOCK_ID,
+        "no cluster-manager",
+        true,
+        true,
+        false,
+        RestStatus.SERVICE_UNAVAILABLE,
+        ClusterBlockLevel.ALL
+    );
+    public static final ClusterBlock NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES = new ClusterBlock(
+        NO_CLUSTER_MANAGER_BLOCK_ID,
+        "no cluster-manager",
+        true,
+        false,
+        false,
+        RestStatus.SERVICE_UNAVAILABLE,
+        EnumSet.of(ClusterBlockLevel.METADATA_WRITE)
+    );
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #NO_CLUSTER_MANAGER_BLOCK_ID} */
+    @Deprecated
+    public static final int NO_MASTER_BLOCK_ID = NO_CLUSTER_MANAGER_BLOCK_ID;
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #NO_CLUSTER_MANAGER_BLOCK_WRITES} */
+    @Deprecated
+    public static final ClusterBlock NO_MASTER_BLOCK_WRITES = NO_CLUSTER_MANAGER_BLOCK_WRITES;
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #NO_CLUSTER_MANAGER_BLOCK_ALL} */
+    @Deprecated
+    public static final ClusterBlock NO_MASTER_BLOCK_ALL = NO_CLUSTER_MANAGER_BLOCK_ALL;
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES} */
+    @Deprecated
+    public static final ClusterBlock NO_MASTER_BLOCK_METADATA_WRITES = NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES;
+
+    public static final Setting<ClusterBlock> NO_MASTER_BLOCK_SETTING = new Setting<>(
+        "cluster.no_master_block",
+        "metadata_write",
+        NoClusterManagerBlockService::parseNoClusterManagerBlock,
+        Property.Dynamic,
+        Property.NodeScope,
+        Property.Deprecated
+    );
+    // The setting below is going to replace the above.
+    // To keep backwards compatibility, the old usage is remained, and it's also used as the fallback for the new usage.
+    public static final Setting<ClusterBlock> NO_CLUSTER_MANAGER_BLOCK_SETTING = new Setting<>(
+        "cluster.no_cluster_manager_block",
+        NO_MASTER_BLOCK_SETTING,
+        NoClusterManagerBlockService::parseNoClusterManagerBlock,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
+    private volatile ClusterBlock noClusterManagerBlock;
+
+    public NoClusterManagerBlockService(Settings settings, ClusterSettings clusterSettings) {
+        this.noClusterManagerBlock = NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(NO_CLUSTER_MANAGER_BLOCK_SETTING, this::setNoClusterManagerBlock);
+    }
+
+    private static ClusterBlock parseNoClusterManagerBlock(String value) {
+        switch (value) {
+            case "all":
+                return NO_CLUSTER_MANAGER_BLOCK_ALL;
+            case "write":
+                return NO_CLUSTER_MANAGER_BLOCK_WRITES;
+            case "metadata_write":
+                return NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES;
+            default:
+                throw new IllegalArgumentException(
+                    "invalid no-cluster-manager block [" + value + "], must be one of [all, write, metadata_write]"
+                );
+        }
+    }
+
+    public ClusterBlock getNoClusterManagerBlock() {
+        return noClusterManagerBlock;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getNoClusterManagerBlock()} */
+    @Deprecated
+    public ClusterBlock getNoMasterBlock() {
+        return noClusterManagerBlock;
+    }
+
+    private void setNoClusterManagerBlock(ClusterBlock noClusterManagerBlock) {
+        this.noClusterManagerBlock = noClusterManagerBlock;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/NoMasterBlockService.java b/server/src/main/java/org/opensearch/cluster/coordination/NoMasterBlockService.java
index 8cbb0446a1337..c759e36b548f9 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/NoMasterBlockService.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/NoMasterBlockService.java
@@ -6,114 +6,22 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.cluster.block.ClusterBlock;
-import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.common.settings.ClusterSettings;
-import org.opensearch.common.settings.Setting;
-import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.RestStatus;
-
-import java.util.EnumSet;
-
-public class NoMasterBlockService {
-    public static final int NO_MASTER_BLOCK_ID = 2;
-    public static final ClusterBlock NO_MASTER_BLOCK_WRITES = new ClusterBlock(
-        NO_MASTER_BLOCK_ID,
-        "no master",
-        true,
-        false,
-        false,
-        RestStatus.SERVICE_UNAVAILABLE,
-        EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE)
-    );
-    public static final ClusterBlock NO_MASTER_BLOCK_ALL = new ClusterBlock(
-        NO_MASTER_BLOCK_ID,
-        "no master",
-        true,
-        true,
-        false,
-        RestStatus.SERVICE_UNAVAILABLE,
-        ClusterBlockLevel.ALL
-    );
-    public static final ClusterBlock NO_MASTER_BLOCK_METADATA_WRITES = new ClusterBlock(
-        NO_MASTER_BLOCK_ID,
-        "no master",
-        true,
-        false,
-        false,
-        RestStatus.SERVICE_UNAVAILABLE,
-        EnumSet.of(ClusterBlockLevel.METADATA_WRITE)
-    );
 
-    public static final Setting<ClusterBlock> NO_MASTER_BLOCK_SETTING = new Setting<>(
-        "cluster.no_master_block",
-        "write",
-        NoMasterBlockService::parseNoMasterBlock,
-        Property.Dynamic,
-        Property.NodeScope,
-        Property.Deprecated
-    );
-    // The setting below is going to replace the above.
-    // To keep backwards compatibility, the old usage is remained, and it's also used as the fallback for the new usage.
-    public static final Setting<ClusterBlock> NO_CLUSTER_MANAGER_BLOCK_SETTING = new Setting<>(
-        "cluster.no_cluster_manager_block",
-        NO_MASTER_BLOCK_SETTING,
-        NoMasterBlockService::parseNoMasterBlock,
-        Property.Dynamic,
-        Property.NodeScope
-    );
-
-    private volatile ClusterBlock noMasterBlock;
+/**
+ * Service to block the master node
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link NoClusterManagerBlockService}
+ */
+@Deprecated
+public class NoMasterBlockService extends NoClusterManagerBlockService {
 
     public NoMasterBlockService(Settings settings, ClusterSettings clusterSettings) {
-        this.noMasterBlock = NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings);
-        clusterSettings.addSettingsUpdateConsumer(NO_CLUSTER_MANAGER_BLOCK_SETTING, this::setNoMasterBlock);
-    }
-
-    private static ClusterBlock parseNoMasterBlock(String value) {
-        switch (value) {
-            case "all":
-                return NO_MASTER_BLOCK_ALL;
-            case "write":
-                return NO_MASTER_BLOCK_WRITES;
-            case "metadata_write":
-                return NO_MASTER_BLOCK_METADATA_WRITES;
-            default:
-                throw new IllegalArgumentException("invalid no-master block [" + value + "], must be one of [all, write, metadata_write]");
-        }
-    }
-
-    public ClusterBlock getNoMasterBlock() {
-        return noMasterBlock;
+        super(settings, clusterSettings);
     }
 
-    private void setNoMasterBlock(ClusterBlock noMasterBlock) {
-        this.noMasterBlock = noMasterBlock;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/NodeHealthCheckFailureException.java b/server/src/main/java/org/opensearch/cluster/coordination/NodeHealthCheckFailureException.java
index 273a220d1eadb..43cc975573072 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/NodeHealthCheckFailureException.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/NodeHealthCheckFailureException.java
@@ -33,13 +33,15 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * This exception is thrown if the File system is reported unhealthy by @{@link org.opensearch.monitor.fs.FsHealthService}
  * and this nodes needs to be removed from the cluster
+ *
+ * @opensearch.internal
  */
 
 public class NodeHealthCheckFailureException extends OpenSearchException {
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/NodeRemovalClusterStateTaskExecutor.java b/server/src/main/java/org/opensearch/cluster/coordination/NodeRemovalClusterStateTaskExecutor.java
index 02bdb65c7edf2..2cf0fb3bffeee 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/NodeRemovalClusterStateTaskExecutor.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/NodeRemovalClusterStateTaskExecutor.java
@@ -43,6 +43,11 @@
 
 import java.util.List;
 
+/**
+ * Update cluster state when node is removed from the cluster
+ *
+ * @opensearch.internal
+ */
 public class NodeRemovalClusterStateTaskExecutor
     implements
         ClusterStateTaskExecutor<NodeRemovalClusterStateTaskExecutor.Task>,
@@ -51,6 +56,11 @@ public class NodeRemovalClusterStateTaskExecutor
     private final AllocationService allocationService;
     private final Logger logger;
 
+    /**
+     * Task for the executor.
+     *
+     * @opensearch.internal
+     */
     public static class Task {
 
         private final DiscoveryNode node;
@@ -126,8 +136,8 @@ public void onFailure(final String source, final Exception e) {
     }
 
     @Override
-    public void onNoLongerMaster(String source) {
-        logger.debug("no longer master while processing node removal [{}]", source);
+    public void onNoLongerClusterManager(String source) {
+        logger.debug("no longer cluster-manager while processing node removal [{}]", source);
     }
 
 }
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/NodeToolCli.java b/server/src/main/java/org/opensearch/cluster/coordination/NodeToolCli.java
index 72a3b3969e2e2..7d51002150fb9 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/NodeToolCli.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/NodeToolCli.java
@@ -39,18 +39,24 @@
 
 // NodeToolCli does not extend LoggingAwareCommand, because LoggingAwareCommand performs logging initialization
 // after LoggingAwareCommand instance is constructed.
-// It's too late for us, because before UnsafeBootstrapMasterCommand is added to the list of subcommands
+// It's too late for us, because before UnsafeBootstrapClusterManagerCommand is added to the list of subcommands
 // log4j2 initialization will happen, because it has static reference to Logger class.
 // Even if we avoid making a static reference to Logger class, there is no nice way to avoid declaring
 // UNSAFE_BOOTSTRAP, which depends on ClusterService, which in turn has static Logger.
 // TODO execute CommandLoggingConfigurator.configureLoggingWithoutConfig() in the constructor of commands, not in beforeMain
+
+/**
+ * Command Line Interface tool for Nodes
+ *
+ * @opensearch.internal
+ */
 public class NodeToolCli extends MultiCommand {
 
     public NodeToolCli() {
         super("A CLI tool to do unsafe cluster and index manipulations on current node", () -> {});
         CommandLoggingConfigurator.configureLoggingWithoutConfig();
         subcommands.put("repurpose", new NodeRepurposeCommand());
-        subcommands.put("unsafe-bootstrap", new UnsafeBootstrapMasterCommand());
+        subcommands.put("unsafe-bootstrap", new UnsafeBootstrapClusterManagerCommand());
         subcommands.put("detach-cluster", new DetachClusterCommand());
         subcommands.put("override-version", new OverrideNodeVersionCommand());
         subcommands.put("remove-settings", new RemoveSettingsCommand());
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/OpenSearchNodeCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/OpenSearchNodeCommand.java
index bc7bd3abbca86..259d8961a3e78 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/OpenSearchNodeCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/OpenSearchNodeCommand.java
@@ -50,13 +50,13 @@
 import org.opensearch.cluster.metadata.DataStreamMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
@@ -70,6 +70,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Main set of node commands
+ *
+ * @opensearch.internal
+ */
 public abstract class OpenSearchNodeCommand extends EnvironmentAwareCommand {
     private static final Logger logger = LogManager.getLogger(OpenSearchNodeCommand.class);
     protected static final String DELIMITER = "------------------------------------------------------------------------\n";
@@ -225,6 +230,11 @@ OptionParser getParser() {
         return parser;
     }
 
+    /**
+     * Custom unknown metadata.
+     *
+     * @opensearch.internal
+     */
     public static class UnknownMetadataCustom implements Metadata.Custom {
 
         private final String name;
@@ -269,6 +279,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * An unknown condition.
+     *
+     * @opensearch.internal
+     */
     public static class UnknownCondition extends Condition<Object> {
 
         public UnknownCondition(String name, Object value) {
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PeersResponse.java b/server/src/main/java/org/opensearch/cluster/coordination/PeersResponse.java
index 76be3ebd3a374..8a70c71d53fdd 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PeersResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PeersResponse.java
@@ -33,37 +33,42 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
+/**
+ * Response from peer nodes
+ *
+ * @opensearch.internal
+ */
 public class PeersResponse extends TransportResponse {
-    private final Optional<DiscoveryNode> masterNode;
+    private final Optional<DiscoveryNode> clusterManagerNode;
     private final List<DiscoveryNode> knownPeers;
     private final long term;
 
-    public PeersResponse(Optional<DiscoveryNode> masterNode, List<DiscoveryNode> knownPeers, long term) {
-        assert masterNode.isPresent() == false || knownPeers.isEmpty();
-        this.masterNode = masterNode;
+    public PeersResponse(Optional<DiscoveryNode> clusterManagerNode, List<DiscoveryNode> knownPeers, long term) {
+        assert clusterManagerNode.isPresent() == false || knownPeers.isEmpty();
+        this.clusterManagerNode = clusterManagerNode;
         this.knownPeers = knownPeers;
         this.term = term;
     }
 
     public PeersResponse(StreamInput in) throws IOException {
-        masterNode = Optional.ofNullable(in.readOptionalWriteable(DiscoveryNode::new));
+        clusterManagerNode = Optional.ofNullable(in.readOptionalWriteable(DiscoveryNode::new));
         knownPeers = in.readList(DiscoveryNode::new);
         term = in.readLong();
-        assert masterNode.isPresent() == false || knownPeers.isEmpty();
+        assert clusterManagerNode.isPresent() == false || knownPeers.isEmpty();
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeOptionalWriteable(masterNode.orElse(null));
+        out.writeOptionalWriteable(clusterManagerNode.orElse(null));
         out.writeList(knownPeers);
         out.writeLong(term);
     }
@@ -71,8 +76,17 @@ public void writeTo(StreamOutput out) throws IOException {
     /**
      * @return the node that is currently leading, according to the responding node.
      */
+    public Optional<DiscoveryNode> getClusterManagerNode() {
+        return clusterManagerNode;
+    }
+
+    /**
+     * @return the node that is currently leading, according to the responding node.
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerNode()}
+     */
+    @Deprecated
     public Optional<DiscoveryNode> getMasterNode() {
-        return masterNode;
+        return getClusterManagerNode();
     }
 
     /**
@@ -93,7 +107,7 @@ public long getTerm() {
 
     @Override
     public String toString() {
-        return "PeersResponse{" + "masterNode=" + masterNode + ", knownPeers=" + knownPeers + ", term=" + term + '}';
+        return "PeersResponse{" + "clusterManagerNode=" + clusterManagerNode + ", knownPeers=" + knownPeers + ", term=" + term + '}';
     }
 
     @Override
@@ -101,11 +115,13 @@ public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         PeersResponse that = (PeersResponse) o;
-        return term == that.term && Objects.equals(masterNode, that.masterNode) && Objects.equals(knownPeers, that.knownPeers);
+        return term == that.term
+            && Objects.equals(clusterManagerNode, that.clusterManagerNode)
+            && Objects.equals(knownPeers, that.knownPeers);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(masterNode, knownPeers, term);
+        return Objects.hash(clusterManagerNode, knownPeers, term);
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PendingClusterStateStats.java b/server/src/main/java/org/opensearch/cluster/coordination/PendingClusterStateStats.java
index 92dd926b2fa0a..9cab59c5fa492 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PendingClusterStateStats.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PendingClusterStateStats.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Class encapsulating stats about the PendingClusterStatsQueue
+ *
+ * @opensearch.internal
  */
 public class PendingClusterStateStats implements Writeable, ToXContentFragment {
 
@@ -90,6 +92,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String QUEUE = "cluster_state_queue";
         static final String TOTAL = "total";
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PersistedStateRegistry.java b/server/src/main/java/org/opensearch/cluster/coordination/PersistedStateRegistry.java
new file mode 100644
index 0000000000000..470ab02a682a8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PersistedStateRegistry.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.cluster.coordination.CoordinationState.PersistedState;
+import org.opensearch.common.util.io.IOUtils;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * A class which encapsulates the PersistedStates
+ *
+ * @opensearch.internal
+ */
+public class PersistedStateRegistry implements Closeable {
+
+    public PersistedStateRegistry() {}
+
+    /**
+     * Distinct Types PersistedState which can be present on a node
+     */
+    public enum PersistedStateType {
+        LOCAL,
+        REMOTE;
+    }
+
+    private final Map<PersistedStateType, PersistedState> persistedStates = new ConcurrentHashMap<>();
+
+    public void addPersistedState(PersistedStateType persistedStateType, PersistedState persistedState) {
+        PersistedState existingState = this.persistedStates.putIfAbsent(persistedStateType, persistedState);
+        assert existingState == null : "should only be set once, but already have " + existingState;
+    }
+
+    public PersistedState getPersistedState(PersistedStateType persistedStateType) {
+        return this.persistedStates.get(persistedStateType);
+    }
+
+    @Override
+    public void close() throws IOException {
+        IOUtils.close(persistedStates.values());
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteCollector.java b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteCollector.java
index 1b934b5f000cd..cc4d1ac156c53 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteCollector.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteCollector.java
@@ -40,8 +40,8 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.threadpool.ThreadPool.Names;
@@ -58,6 +58,11 @@
 import static org.opensearch.common.util.concurrent.ConcurrentCollections.newConcurrentMap;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Collects information prior to a promotion vote
+ *
+ * @opensearch.internal
+ */
 public class PreVoteCollector {
 
     private static final Logger logger = LogManager.getLogger(PreVoteCollector.class);
@@ -162,6 +167,11 @@ public String toString() {
         return "PreVoteCollector{" + "state=" + state + '}';
     }
 
+    /**
+     * The pre vote round.
+     *
+     * @opensearch.internal
+     */
     private class PreVotingRound implements Releasable {
         private final Map<DiscoveryNode, PreVoteResponse> preVotesReceived = newConcurrentMap();
         private final AtomicBoolean electionStarted = new AtomicBoolean();
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteRequest.java
index e99b2716a263f..85632bdc06e75 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteRequest.java
@@ -33,13 +33,18 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Requests pre vote information collection
+ *
+ * @opensearch.internal
+ */
 public class PreVoteRequest extends TransportRequest {
 
     private final DiscoveryNode sourceNode;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteResponse.java b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteResponse.java
index 09259867ebf53..9c683f7de0878 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PreVoteResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PreVoteResponse.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Response for a PreVoteRequest
+ *
+ * @opensearch.internal
+ */
 public class PreVoteResponse extends TransportResponse {
     private final long currentTerm;
     private final long lastAcceptedTerm;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/Publication.java b/server/src/main/java/org/opensearch/cluster/coordination/Publication.java
index 5529c3248345c..43801a05dbc24 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/Publication.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/Publication.java
@@ -37,13 +37,13 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.ClusterStatePublisher.AckListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -52,6 +52,11 @@
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
 
+/**
+ * Publication task
+ *
+ * @opensearch.internal
+ */
 public abstract class Publication {
 
     protected final Logger logger = LogManager.getLogger(getClass());
@@ -73,7 +78,10 @@ public Publication(PublishRequest publishRequest, AckListener ackListener, LongS
         startTime = currentTimeSupplier.getAsLong();
         applyCommitRequest = Optional.empty();
         publicationTargets = new ArrayList<>(publishRequest.getAcceptedState().getNodes().getNodes().size());
-        publishRequest.getAcceptedState().getNodes().mastersFirstStream().forEach(n -> publicationTargets.add(new PublicationTarget(n)));
+        publishRequest.getAcceptedState()
+            .getNodes()
+            .clusterManagersFirstStream()
+            .forEach(n -> publicationTargets.add(new PublicationTarget(n)));
     }
 
     public void start(Set<DiscoveryNode> faultyNodes) {
@@ -247,6 +255,11 @@ enum PublicationTargetState {
         APPLIED_COMMIT,
     }
 
+    /**
+     * A publication target.
+     *
+     * @opensearch.internal
+     */
     class PublicationTarget {
         private final DiscoveryNode discoveryNode;
         private boolean ackIsPending = true;
@@ -358,6 +371,11 @@ boolean isFailed() {
             return state == PublicationTargetState.FAILED;
         }
 
+        /**
+         * A handler for a publish response.
+         *
+         * @opensearch.internal
+         */
         private class PublishResponseHandler implements ActionListener<PublishWithJoinResponse> {
 
             @Override
@@ -399,6 +417,11 @@ public void onFailure(Exception e) {
 
         }
 
+        /**
+         * An apply commit response handler.
+         *
+         * @opensearch.internal
+         */
         private class ApplyCommitResponseHandler implements ActionListener<TransportResponse.Empty> {
 
             @Override
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PublicationTransportHandler.java b/server/src/main/java/org/opensearch/cluster/coordination/PublicationTransportHandler.java
index ee97c0e07eb48..1fdaeead0d28d 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PublicationTransportHandler.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PublicationTransportHandler.java
@@ -36,30 +36,22 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.IncompatibleClusterStateVersionException;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.Compressor;
-import org.opensearch.common.compress.CompressorFactory;
-import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.BytesTransportRequest;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -72,6 +64,11 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+/**
+ * Transport handler for publication
+ *
+ * @opensearch.internal
+ */
 public class PublicationTransportHandler {
 
     private static final Logger logger = LogManager.getLogger(PublicationTransportHandler.class);
@@ -85,7 +82,7 @@ public class PublicationTransportHandler {
 
     private final AtomicReference<ClusterState> lastSeenClusterState = new AtomicReference<>();
 
-    // the master needs the original non-serialized state as the cluster state contains some volatile information that we
+    // the cluster-manager needs the original non-serialized state as the cluster state contains some volatile information that we
     // don't want to be replicated because it's not usable on another node (e.g. UnassignedInfo.unassignedTimeNanos) or
     // because it's mostly just debugging info that would unnecessarily blow up CS updates (I think there was one in
     // snapshot code).
@@ -163,17 +160,9 @@ public PublishClusterStateStats stats() {
     }
 
     private PublishWithJoinResponse handleIncomingPublishRequest(BytesTransportRequest request) throws IOException {
-        final Compressor compressor = CompressorFactory.compressor(request.bytes());
-        StreamInput in = request.bytes().streamInput();
-        try {
-            if (compressor != null) {
-                in = new InputStreamStreamInput(compressor.threadLocalInputStream(in));
-            }
-            in = new NamedWriteableAwareStreamInput(in, namedWriteableRegistry);
-            in.setVersion(request.version());
-            // If true we received full cluster state - otherwise diffs
+        try (StreamInput in = CompressedStreamUtils.decompressBytes(request, namedWriteableRegistry)) {
+            ClusterState incomingState;
             if (in.readBoolean()) {
-                final ClusterState incomingState;
                 // Close early to release resources used by the de-compression as early as possible
                 try (StreamInput input = in) {
                     incomingState = ClusterState.readFrom(input, transportService.getLocalNode());
@@ -193,7 +182,6 @@ private PublishWithJoinResponse handleIncomingPublishRequest(BytesTransportReque
                     incompatibleClusterStateDiffReceivedCount.incrementAndGet();
                     throw new IncompatibleClusterStateVersionException("have no local cluster state");
                 } else {
-                    ClusterState incomingState;
                     try {
                         final Diff<ClusterState> diff;
                         // Close stream early to release resources used by the de-compression as early as possible
@@ -220,14 +208,12 @@ private PublishWithJoinResponse handleIncomingPublishRequest(BytesTransportReque
                     return response;
                 }
             }
-        } finally {
-            IOUtils.close(in);
         }
     }
 
     private PublishWithJoinResponse acceptState(ClusterState incomingState) {
         // if the state is coming from the current node, use original request instead (see currentPublishRequestToSelf for explanation)
-        if (transportService.getLocalNode().equals(incomingState.nodes().getMasterNode())) {
+        if (transportService.getLocalNode().equals(incomingState.nodes().getClusterManagerNode())) {
             final PublishRequest publishRequest = currentPublishRequestToSelf.get();
             if (publishRequest == null || publishRequest.getAcceptedState().stateUUID().equals(incomingState.stateUUID()) == false) {
                 throw new IllegalStateException("publication to self failed for " + publishRequest);
@@ -249,13 +235,10 @@ public PublicationContext newPublicationContext(ClusterChangedEvent clusterChang
     }
 
     private static BytesReference serializeFullClusterState(ClusterState clusterState, Version nodeVersion) throws IOException {
-        final BytesStreamOutput bStream = new BytesStreamOutput();
-        try (StreamOutput stream = new OutputStreamStreamOutput(CompressorFactory.COMPRESSOR.threadLocalOutputStream(bStream))) {
-            stream.setVersion(nodeVersion);
+        final BytesReference serializedState = CompressedStreamUtils.createCompressedStream(nodeVersion, stream -> {
             stream.writeBoolean(true);
             clusterState.writeTo(stream);
-        }
-        final BytesReference serializedState = bStream.bytes();
+        });
         logger.trace(
             "serialized full cluster state version [{}] for node version [{}] with size [{}]",
             clusterState.version(),
@@ -266,19 +249,18 @@ private static BytesReference serializeFullClusterState(ClusterState clusterStat
     }
 
     private static BytesReference serializeDiffClusterState(Diff<ClusterState> diff, Version nodeVersion) throws IOException {
-        final BytesStreamOutput bStream = new BytesStreamOutput();
-        try (StreamOutput stream = new OutputStreamStreamOutput(CompressorFactory.COMPRESSOR.threadLocalOutputStream(bStream))) {
-            stream.setVersion(nodeVersion);
+        return CompressedStreamUtils.createCompressedStream(nodeVersion, stream -> {
             stream.writeBoolean(false);
             diff.writeTo(stream);
-        }
-        return bStream.bytes();
+        });
     }
 
     /**
      * Publishing a cluster state typically involves sending the same cluster state (or diff) to every node, so the work of diffing,
      * serializing, and compressing the state can be done once and the results shared across publish requests. The
      * {@code PublicationContext} implements this sharing.
+     *
+     * @opensearch.internal
      */
     public class PublicationContext {
 
@@ -337,8 +319,9 @@ public void sendPublishRequest(
             if (destination.equals(discoveryNodes.getLocalNode())) {
                 // if publishing to self, use original request instead (see currentPublishRequestToSelf for explanation)
                 final PublishRequest previousRequest = currentPublishRequestToSelf.getAndSet(publishRequest);
-                // we might override an in-flight publication to self in case where we failed as master and became master again,
-                // and the new publication started before the previous one completed (which fails anyhow because of higher current term)
+                // we might override an in-flight publication to self in case where we failed as cluster-manager and
+                // became cluster-manager again, and the new publication started before the previous one completed
+                // (which fails anyhow because of higher current term)
                 assert previousRequest == null || previousRequest.getAcceptedState().term() < publishRequest.getAcceptedState().term();
                 responseActionListener = new ActionListener<PublishWithJoinResponse>() {
                     @Override
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PublishClusterStateStats.java b/server/src/main/java/org/opensearch/cluster/coordination/PublishClusterStateStats.java
index 77320810eba4c..6a1dca0d27208 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PublishClusterStateStats.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PublishClusterStateStats.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Class encapsulating stats about the PublishClusterStateAction
+ *
+ * @opensearch.internal
  */
 public class PublishClusterStateStats implements Writeable, ToXContentObject {
 
@@ -50,8 +52,8 @@ public class PublishClusterStateStats implements Writeable, ToXContentObject {
     private final long compatibleClusterStateDiffReceivedCount;
 
     /**
-     * @param fullClusterStateReceivedCount the number of times this node has received a full copy of the cluster state from the master.
-     * @param incompatibleClusterStateDiffReceivedCount the number of times this node has received a cluster-state diff from the master.
+     * @param fullClusterStateReceivedCount the number of times this node has received a full copy of the cluster state from the cluster-manager.
+     * @param incompatibleClusterStateDiffReceivedCount the number of times this node has received a cluster-state diff from the cluster-manager.
      * @param compatibleClusterStateDiffReceivedCount the number of times that received cluster-state diffs were compatible with
      */
     public PublishClusterStateStats(
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PublishRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/PublishRequest.java
index 76517573115fd..e7c3e2d2c965b 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PublishRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PublishRequest.java
@@ -36,8 +36,10 @@
 import java.util.Objects;
 
 /**
- * Request which is used by the master node to publish cluster state changes.
+ * Request which is used by the cluster-manager node to publish cluster state changes.
  * Actual serialization of this request is done by {@link PublicationTransportHandler}
+ *
+ * @opensearch.internal
  */
 public class PublishRequest {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PublishResponse.java b/server/src/main/java/org/opensearch/cluster/coordination/PublishResponse.java
index 9d219331c0d0e..23a60cb88283e 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PublishResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PublishResponse.java
@@ -31,15 +31,17 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
 /**
  * Response to a {@link PublishRequest}, carrying the term and version of the request.
  * Typically wrapped in a {@link PublishWithJoinResponse}.
+ *
+ * @opensearch.internal
  */
 public class PublishResponse implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/PublishWithJoinResponse.java b/server/src/main/java/org/opensearch/cluster/coordination/PublishWithJoinResponse.java
index 430e539fd3255..f6350c5558a82 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/PublishWithJoinResponse.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/PublishWithJoinResponse.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.Optional;
@@ -41,6 +41,8 @@
 /**
  * Response to a {@link PublishRequest}. Encapsulates both a {@link PublishResponse}
  * and an optional {@link Join}.
+ *
+ * @opensearch.internal
  */
 public class PublishWithJoinResponse extends TransportResponse {
     private final PublishResponse publishResponse;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/Reconfigurator.java b/server/src/main/java/org/opensearch/cluster/coordination/Reconfigurator.java
index 26f289f5547d6..1570a84ab871f 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/Reconfigurator.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/Reconfigurator.java
@@ -47,24 +47,26 @@
 
 /**
  * Computes the optimal configuration of voting nodes in the cluster.
+ *
+ * @opensearch.internal
  */
 public class Reconfigurator {
 
     private static final Logger logger = LogManager.getLogger(Reconfigurator.class);
 
     /**
-     * The cluster usually requires a vote from at least half of the master nodes in order to commit a cluster state update, and to achieve
-     * the best resilience it makes automatic adjustments to the voting configuration as master nodes join or leave the cluster. Adjustments
+     * The cluster usually requires a vote from at least half of the cluster-manager nodes in order to commit a cluster state update, and to achieve
+     * the best resilience it makes automatic adjustments to the voting configuration as cluster-manager nodes join or leave the cluster. Adjustments
      * that fix or increase the size of the voting configuration are always a good idea, but the wisdom of reducing the voting configuration
      * size is less clear. For instance, automatically reducing the voting configuration down to a single node means the cluster requires
-     * this node to operate, which is not resilient: if it broke we could restore every other master-eligible node in the cluster to health
+     * this node to operate, which is not resilient: if it broke we could restore every other cluster-manager-eligible node in the cluster to health
      * and still the cluster would be unavailable. However not reducing the voting configuration size can also hamper resilience: in a
      * five-node cluster we could lose two nodes and by reducing the voting configuration to the remaining three nodes we could tolerate the
      * loss of a further node before failing.
      *
      * We offer two options: either we auto-shrink the voting configuration as long as it contains more than three nodes, or we don't and we
      * require the user to control the voting configuration manually using the retirement API. The former, default, option, guarantees that
-     * as long as there have been at least three master-eligible nodes in the cluster and no more than one of them is currently unavailable,
+     * as long as there have been at least three cluster-manager-eligible nodes in the cluster and no more than one of them is currently unavailable,
      * then the cluster will still operate, which is what almost everyone wants. Manual control is for users who want different guarantees.
      */
     public static final Setting<Boolean> CLUSTER_AUTO_SHRINK_VOTING_CONFIGURATION = Setting.boolSetting(
@@ -102,39 +104,44 @@ public String toString() {
      * @param retiredNodeIds Nodes that are leaving the cluster and which should not appear in the configuration if possible. Nodes that are
      *                       retired and not in the current configuration will never appear in the resulting configuration; this is useful
      *                       for shifting the vote in a 2-node cluster so one of the nodes can be restarted without harming availability.
-     * @param currentMaster  The current master. Unless retired, we prefer to keep the current master in the config.
+     * @param currentClusterManager  The current cluster-manager. Unless retired, we prefer to keep the current cluster-manager in the config.
      * @param currentConfig  The current configuration. As far as possible, we prefer to keep the current config as-is.
      * @return An optimal configuration, or leave the current configuration unchanged if the optimal configuration has no live quorum.
      */
     public VotingConfiguration reconfigure(
         Set<DiscoveryNode> liveNodes,
         Set<String> retiredNodeIds,
-        DiscoveryNode currentMaster,
+        DiscoveryNode currentClusterManager,
         VotingConfiguration currentConfig
     ) {
-        assert liveNodes.contains(currentMaster) : "liveNodes = " + liveNodes + " master = " + currentMaster;
+        assert liveNodes.contains(currentClusterManager) : "liveNodes = " + liveNodes + " cluster-manager = " + currentClusterManager;
         logger.trace(
-            "{} reconfiguring {} based on liveNodes={}, retiredNodeIds={}, currentMaster={}",
+            "{} reconfiguring {} based on liveNodes={}, retiredNodeIds={}, currentClusterManager={}",
             this,
             currentConfig,
             liveNodes,
             retiredNodeIds,
-            currentMaster
+            currentClusterManager
         );
 
         final Set<String> liveNodeIds = liveNodes.stream()
-            .filter(DiscoveryNode::isMasterNode)
+            .filter(DiscoveryNode::isClusterManagerNode)
             .map(DiscoveryNode::getId)
             .collect(Collectors.toSet());
         final Set<String> currentConfigNodeIds = currentConfig.getNodeIds();
 
         final Set<VotingConfigNode> orderedCandidateNodes = new TreeSet<>();
         liveNodes.stream()
-            .filter(DiscoveryNode::isMasterNode)
+            .filter(DiscoveryNode::isClusterManagerNode)
             .filter(n -> retiredNodeIds.contains(n.getId()) == false)
             .forEach(
                 n -> orderedCandidateNodes.add(
-                    new VotingConfigNode(n.getId(), true, n.getId().equals(currentMaster.getId()), currentConfigNodeIds.contains(n.getId()))
+                    new VotingConfigNode(
+                        n.getId(),
+                        true,
+                        n.getId().equals(currentClusterManager.getId()),
+                        currentConfigNodeIds.contains(n.getId())
+                    )
                 )
             );
         currentConfigNodeIds.stream()
@@ -163,25 +170,30 @@ public VotingConfiguration reconfigure(
         }
     }
 
+    /**
+     * A node to handle voting configs.
+     *
+     * @opensearch.internal
+     */
     static class VotingConfigNode implements Comparable<VotingConfigNode> {
         final String id;
         final boolean live;
-        final boolean currentMaster;
+        final boolean currentClusterManager;
         final boolean inCurrentConfig;
 
-        VotingConfigNode(String id, boolean live, boolean currentMaster, boolean inCurrentConfig) {
+        VotingConfigNode(String id, boolean live, boolean currentClusterManager, boolean inCurrentConfig) {
             this.id = id;
             this.live = live;
-            this.currentMaster = currentMaster;
+            this.currentClusterManager = currentClusterManager;
             this.inCurrentConfig = inCurrentConfig;
         }
 
         @Override
         public int compareTo(VotingConfigNode other) {
-            // prefer current master
-            final int currentMasterComp = Boolean.compare(other.currentMaster, currentMaster);
-            if (currentMasterComp != 0) {
-                return currentMasterComp;
+            // prefer current cluster-manager
+            final int currentClusterManagerComp = Boolean.compare(other.currentClusterManager, currentClusterManager);
+            if (currentClusterManagerComp != 0) {
+                return currentClusterManagerComp;
             }
             // prefer nodes that are live
             final int liveComp = Boolean.compare(other.live, live);
@@ -205,8 +217,8 @@ public String toString() {
                 + '\''
                 + ", live="
                 + live
-                + ", currentMaster="
-                + currentMaster
+                + ", currentClusterManager="
+                + currentClusterManager
                 + ", inCurrentConfig="
                 + inCurrentConfig
                 + '}';
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/RemoveCustomsCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/RemoveCustomsCommand.java
index 83f3298862776..8dad8e3836635 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/RemoveCustomsCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/RemoveCustomsCommand.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.cluster.coordination;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 import org.opensearch.cli.ExitCodes;
@@ -48,6 +47,11 @@
 import java.nio.file.Path;
 import java.util.List;
 
+/**
+ * Removes custom metadata
+ *
+ * @opensearch.internal
+ */
 public class RemoveCustomsCommand extends OpenSearchNodeCommand {
 
     static final String CUSTOMS_REMOVED_MSG = "Customs were successfully removed from the cluster state";
@@ -79,12 +83,11 @@ protected void processNodePaths(Terminal terminal, Path[] dataPaths, int nodeLoc
         terminal.println(Terminal.Verbosity.VERBOSE, "Loading cluster state");
         final Tuple<Long, ClusterState> termAndClusterState = loadTermAndClusterState(persistedClusterStateService, env);
         final ClusterState oldClusterState = termAndClusterState.v2();
-        terminal.println(Terminal.Verbosity.VERBOSE, "custom metadata names: " + oldClusterState.metadata().customs().keys());
+        terminal.println(Terminal.Verbosity.VERBOSE, "custom metadata names: " + oldClusterState.metadata().customs().keySet());
         final Metadata.Builder metadataBuilder = Metadata.builder(oldClusterState.metadata());
         for (String customToRemove : customsToRemove) {
             boolean matched = false;
-            for (ObjectCursor<String> customKeyCur : oldClusterState.metadata().customs().keys()) {
-                final String customKey = customKeyCur.value;
+            for (final String customKey : oldClusterState.metadata().customs().keySet()) {
                 if (Regex.simpleMatch(customToRemove, customKey)) {
                     metadataBuilder.removeCustom(customKey);
                     if (matched == false) {
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/RemoveSettingsCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/RemoveSettingsCommand.java
index 298dfde7858cd..da7adec6c4f11 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/RemoveSettingsCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/RemoveSettingsCommand.java
@@ -48,6 +48,11 @@
 import java.nio.file.Path;
 import java.util.List;
 
+/**
+ * Removes custom settings
+ *
+ * @opensearch.internal
+ */
 public class RemoveSettingsCommand extends OpenSearchNodeCommand {
 
     static final String SETTINGS_REMOVED_MSG = "Settings were successfully removed from the cluster state";
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/StartJoinRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/StartJoinRequest.java
index efdbd37a9c0b6..de58eb721b28f 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/StartJoinRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/StartJoinRequest.java
@@ -32,8 +32,8 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
@@ -41,6 +41,8 @@
 /**
  * Represents the action of requesting a join vote (see {@link Join}) from a node.
  * The source node represents the node that is asking for join votes.
+ *
+ * @opensearch.internal
  */
 public class StartJoinRequest extends TransportRequest {
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/TermVersionRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/TermVersionRequest.java
index cea8c43302a23..81923f4211b7e 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/TermVersionRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/TermVersionRequest.java
@@ -32,13 +32,18 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Get's the version of a term
+ *
+ * @opensearch.internal
+ */
 abstract class TermVersionRequest extends TransportRequest implements Writeable {
     protected final DiscoveryNode sourceNode;
     protected final long term;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapClusterManagerCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapClusterManagerCommand.java
new file mode 100644
index 0000000000000..168ae5212888f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapClusterManagerCommand.java
@@ -0,0 +1,192 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import joptsimple.OptionSet;
+import joptsimple.OptionSpec;
+import org.opensearch.OpenSearchException;
+import org.opensearch.cli.Terminal;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.env.Environment;
+import org.opensearch.gateway.PersistedClusterStateService;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.Locale;
+import java.util.Objects;
+
+import static org.opensearch.gateway.remote.RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING;
+
+/**
+ * Tool to run an unsafe bootstrap
+ *
+ * @opensearch.internal
+ */
+public class UnsafeBootstrapClusterManagerCommand extends OpenSearchNodeCommand {
+
+    static final String CLUSTER_STATE_TERM_VERSION_MSG_FORMAT = "Current node cluster state (term, version) pair is (%s, %s)";
+    static final String CONFIRMATION_MSG = DELIMITER
+        + "\n"
+        + "You should only run this tool if you have permanently lost half or more\n"
+        + "of the cluster-manager-eligible nodes in this cluster, and you cannot restore the\n"
+        + "cluster from a snapshot. This tool can cause arbitrary data loss and its\n"
+        + "use should be your last resort. If you have multiple surviving cluster-manager\n"
+        + "eligible nodes, you should run this tool on the node with the highest\n"
+        + "cluster state (term, version) pair.\n"
+        + "\n"
+        + "Do you want to proceed?\n";
+
+    static final String NOT_CLUSTER_MANAGER_NODE_MSG = "unsafe-bootstrap tool can only be run on cluster-manager eligible node";
+
+    static final String EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG =
+        "last committed voting voting configuration is empty, cluster has never been bootstrapped?";
+
+    static final String CLUSTER_MANAGER_NODE_BOOTSTRAPPED_MSG = "Cluster-manager node was successfully bootstrapped";
+    static final Setting<String> UNSAFE_BOOTSTRAP = ClusterService.USER_DEFINED_METADATA.getConcreteSetting(
+        "cluster.metadata.unsafe-bootstrap"
+    );
+    static final String REMOTE_CLUSTER_STATE_ENABLED_NODE =
+        "Unsafe bootstrap cannot be performed when remote cluster state is enabled. The cluster state in the remote store is considered the source of truth. "
+            + "In case, you still wish to do best effort recovery with unsafe-bootstrap, then please disable the "
+            + REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey()
+            + ". For more details, please check the OpenSearch documentation.";
+    private OptionSpec<Boolean> applyClusterReadOnlyBlockOption;
+
+    UnsafeBootstrapClusterManagerCommand() {
+        super(
+            "Forces the successful election of the current node after the permanent loss of the half or more cluster-manager-eligible nodes"
+        );
+        applyClusterReadOnlyBlockOption = parser.accepts("apply-cluster-read-only-block", "Optional cluster.blocks.read_only setting")
+            .withOptionalArg()
+            .ofType(Boolean.class);
+    }
+
+    @Override
+    protected boolean validateBeforeLock(Terminal terminal, Environment env) {
+        Settings settings = env.settings();
+        terminal.println(Terminal.Verbosity.VERBOSE, "Checking node.roles setting");
+        Boolean clusterManager = DiscoveryNode.isClusterManagerNode(settings);
+        if (clusterManager == false) {
+            throw new OpenSearchException(NOT_CLUSTER_MANAGER_NODE_MSG);
+        }
+        // During unsafe bootstrap, node will form a cluster with a new cluster UUID but with the existing metadata.
+        // This new state will not know about the previous cluster UUIDs and so we will not able to construct
+        // the cluster UUID chain to get the last known cluster UUID to restore from.
+        // Blocking unsafe-bootstrap below for this reason.
+        if (REMOTE_CLUSTER_STATE_ENABLED_SETTING.get(settings) == true) {
+            throw new OpenSearchException(REMOTE_CLUSTER_STATE_ENABLED_NODE);
+        }
+
+        return true;
+    }
+
+    protected void processNodePaths(Terminal terminal, Path[] dataPaths, int nodeLockId, OptionSet options, Environment env)
+        throws IOException {
+        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
+
+        final Tuple<Long, ClusterState> state = loadTermAndClusterState(persistedClusterStateService, env);
+        final ClusterState oldClusterState = state.v2();
+
+        final Metadata metadata = oldClusterState.metadata();
+
+        final CoordinationMetadata coordinationMetadata = metadata.coordinationMetadata();
+        if (coordinationMetadata == null
+            || coordinationMetadata.getLastCommittedConfiguration() == null
+            || coordinationMetadata.getLastCommittedConfiguration().isEmpty()) {
+            throw new OpenSearchException(EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG);
+        }
+        terminal.println(
+            String.format(Locale.ROOT, CLUSTER_STATE_TERM_VERSION_MSG_FORMAT, coordinationMetadata.term(), metadata.version())
+        );
+
+        CoordinationMetadata newCoordinationMetadata = CoordinationMetadata.builder(coordinationMetadata)
+            .clearVotingConfigExclusions()
+            .lastAcceptedConfiguration(
+                new CoordinationMetadata.VotingConfiguration(Collections.singleton(persistedClusterStateService.getNodeId()))
+            )
+            .lastCommittedConfiguration(
+                new CoordinationMetadata.VotingConfiguration(Collections.singleton(persistedClusterStateService.getNodeId()))
+            )
+            .build();
+
+        Settings persistentSettings = Settings.builder().put(metadata.persistentSettings()).put(UNSAFE_BOOTSTRAP.getKey(), true).build();
+
+        Boolean applyClusterReadOnlyBlock = applyClusterReadOnlyBlockOption.value(options);
+        if (Objects.nonNull(applyClusterReadOnlyBlock)) {
+            persistentSettings = Settings.builder()
+                .put(persistentSettings)
+                .put(Metadata.SETTING_READ_ONLY_SETTING.getKey(), applyClusterReadOnlyBlock)
+                .build();
+        }
+
+        Metadata.Builder newMetadata = Metadata.builder(metadata)
+            .clusterUUID(Metadata.UNKNOWN_CLUSTER_UUID)
+            .generateClusterUuidIfNeeded()
+            .clusterUUIDCommitted(true)
+            .persistentSettings(persistentSettings)
+            .coordinationMetadata(newCoordinationMetadata);
+        for (final IndexMetadata indexMetadata : metadata.indices().values()) {
+            newMetadata.put(
+                IndexMetadata.builder(indexMetadata)
+                    .settings(
+                        Settings.builder()
+                            .put(indexMetadata.getSettings())
+                            .put(IndexMetadata.SETTING_HISTORY_UUID, UUIDs.randomBase64UUID())
+                    )
+            );
+        }
+
+        final ClusterState newClusterState = ClusterState.builder(oldClusterState).metadata(newMetadata).build();
+
+        terminal.println(
+            Terminal.Verbosity.VERBOSE,
+            "[old cluster state = " + oldClusterState + ", new cluster state = " + newClusterState + "]"
+        );
+
+        confirm(terminal, CONFIRMATION_MSG);
+
+        try (PersistedClusterStateService.Writer writer = persistedClusterStateService.createWriter()) {
+            writer.writeFullStateAndCommit(state.v1(), newClusterState);
+        }
+
+        terminal.println(CLUSTER_MANAGER_NODE_BOOTSTRAPPED_MSG);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapMasterCommand.java b/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapMasterCommand.java
index e61b6448f6ac9..9a8bfd5ed1e35 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapMasterCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapMasterCommand.java
@@ -6,169 +6,19 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster.coordination;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import joptsimple.OptionSet;
-import joptsimple.OptionSpec;
-import org.opensearch.OpenSearchException;
-import org.opensearch.cli.Terminal;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.settings.Setting;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.env.Environment;
-import org.opensearch.gateway.PersistedClusterStateService;
-
-import java.io.IOException;
-import java.nio.file.Path;
-import java.util.Collections;
-import java.util.Locale;
-import java.util.Objects;
-
-public class UnsafeBootstrapMasterCommand extends OpenSearchNodeCommand {
-
-    static final String CLUSTER_STATE_TERM_VERSION_MSG_FORMAT = "Current node cluster state (term, version) pair is (%s, %s)";
-    static final String CONFIRMATION_MSG = DELIMITER
-        + "\n"
-        + "You should only run this tool if you have permanently lost half or more\n"
-        + "of the master-eligible nodes in this cluster, and you cannot restore the\n"
-        + "cluster from a snapshot. This tool can cause arbitrary data loss and its\n"
-        + "use should be your last resort. If you have multiple surviving master\n"
-        + "eligible nodes, you should run this tool on the node with the highest\n"
-        + "cluster state (term, version) pair.\n"
-        + "\n"
-        + "Do you want to proceed?\n";
-
-    static final String NOT_MASTER_NODE_MSG = "unsafe-bootstrap tool can only be run on master eligible node";
-
-    static final String EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG =
-        "last committed voting voting configuration is empty, cluster has never been bootstrapped?";
-
-    static final String MASTER_NODE_BOOTSTRAPPED_MSG = "Master node was successfully bootstrapped";
-    static final Setting<String> UNSAFE_BOOTSTRAP = ClusterService.USER_DEFINED_METADATA.getConcreteSetting(
-        "cluster.metadata.unsafe-bootstrap"
-    );
-
-    private OptionSpec<Boolean> applyClusterReadOnlyBlockOption;
+/**
+ * Tool to run an unsafe bootstrap
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link UnsafeBootstrapClusterManagerCommand}
+ */
+@Deprecated
+public class UnsafeBootstrapMasterCommand extends UnsafeBootstrapClusterManagerCommand {
 
     UnsafeBootstrapMasterCommand() {
-        super("Forces the successful election of the current node after the permanent loss of the half or more master-eligible nodes");
-        applyClusterReadOnlyBlockOption = parser.accepts("apply-cluster-read-only-block", "Optional cluster.blocks.read_only setting")
-            .withOptionalArg()
-            .ofType(Boolean.class);
+        super();
     }
 
-    @Override
-    protected boolean validateBeforeLock(Terminal terminal, Environment env) {
-        Settings settings = env.settings();
-        terminal.println(Terminal.Verbosity.VERBOSE, "Checking node.master setting");
-        Boolean master = DiscoveryNode.isMasterNode(settings);
-        if (master == false) {
-            throw new OpenSearchException(NOT_MASTER_NODE_MSG);
-        }
-
-        return true;
-    }
-
-    protected void processNodePaths(Terminal terminal, Path[] dataPaths, int nodeLockId, OptionSet options, Environment env)
-        throws IOException {
-        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
-
-        final Tuple<Long, ClusterState> state = loadTermAndClusterState(persistedClusterStateService, env);
-        final ClusterState oldClusterState = state.v2();
-
-        final Metadata metadata = oldClusterState.metadata();
-
-        final CoordinationMetadata coordinationMetadata = metadata.coordinationMetadata();
-        if (coordinationMetadata == null
-            || coordinationMetadata.getLastCommittedConfiguration() == null
-            || coordinationMetadata.getLastCommittedConfiguration().isEmpty()) {
-            throw new OpenSearchException(EMPTY_LAST_COMMITTED_VOTING_CONFIG_MSG);
-        }
-        terminal.println(
-            String.format(Locale.ROOT, CLUSTER_STATE_TERM_VERSION_MSG_FORMAT, coordinationMetadata.term(), metadata.version())
-        );
-
-        CoordinationMetadata newCoordinationMetadata = CoordinationMetadata.builder(coordinationMetadata)
-            .clearVotingConfigExclusions()
-            .lastAcceptedConfiguration(
-                new CoordinationMetadata.VotingConfiguration(Collections.singleton(persistedClusterStateService.getNodeId()))
-            )
-            .lastCommittedConfiguration(
-                new CoordinationMetadata.VotingConfiguration(Collections.singleton(persistedClusterStateService.getNodeId()))
-            )
-            .build();
-
-        Settings persistentSettings = Settings.builder().put(metadata.persistentSettings()).put(UNSAFE_BOOTSTRAP.getKey(), true).build();
-
-        Boolean applyClusterReadOnlyBlock = applyClusterReadOnlyBlockOption.value(options);
-        if (Objects.nonNull(applyClusterReadOnlyBlock)) {
-            persistentSettings = Settings.builder()
-                .put(persistentSettings)
-                .put(Metadata.SETTING_READ_ONLY_SETTING.getKey(), applyClusterReadOnlyBlock)
-                .build();
-        }
-
-        Metadata.Builder newMetadata = Metadata.builder(metadata)
-            .clusterUUID(Metadata.UNKNOWN_CLUSTER_UUID)
-            .generateClusterUuidIfNeeded()
-            .clusterUUIDCommitted(true)
-            .persistentSettings(persistentSettings)
-            .coordinationMetadata(newCoordinationMetadata);
-        for (ObjectCursor<IndexMetadata> idx : metadata.indices().values()) {
-            IndexMetadata indexMetadata = idx.value;
-            newMetadata.put(
-                IndexMetadata.builder(indexMetadata)
-                    .settings(
-                        Settings.builder()
-                            .put(indexMetadata.getSettings())
-                            .put(IndexMetadata.SETTING_HISTORY_UUID, UUIDs.randomBase64UUID())
-                    )
-            );
-        }
-
-        final ClusterState newClusterState = ClusterState.builder(oldClusterState).metadata(newMetadata).build();
-
-        terminal.println(
-            Terminal.Verbosity.VERBOSE,
-            "[old cluster state = " + oldClusterState + ", new cluster state = " + newClusterState + "]"
-        );
-
-        confirm(terminal, CONFIRMATION_MSG);
-
-        try (PersistedClusterStateService.Writer writer = persistedClusterStateService.createWriter()) {
-            writer.writeFullStateAndCommit(state.v1(), newClusterState);
-        }
-
-        terminal.println(MASTER_NODE_BOOTSTRAPPED_MSG);
-    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/ValidateJoinRequest.java b/server/src/main/java/org/opensearch/cluster/coordination/ValidateJoinRequest.java
index afdd124bddef2..34bbfc09d92dd 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/ValidateJoinRequest.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/ValidateJoinRequest.java
@@ -32,12 +32,17 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Transport request to validate node join
+ *
+ * @opensearch.internal
+ */
 public class ValidateJoinRequest extends TransportRequest {
     private ClusterState state;
 
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/package-info.java b/server/src/main/java/org/opensearch/cluster/coordination/package-info.java
new file mode 100644
index 0000000000000..2f0514f25f6d6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/coordination/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Coordination foundation classes. */
+package org.opensearch.cluster.coordination;
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttribute.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttribute.java
new file mode 100644
index 0000000000000..3f67870781580
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttribute.java
@@ -0,0 +1,92 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * {@link DecommissionAttribute} encapsulates information about decommissioned node attribute like attribute name, attribute value.
+ *
+ * @opensearch.internal
+ */
+public final class DecommissionAttribute implements Writeable {
+    private final String attributeName;
+    private final String attributeValue;
+
+    /**
+     * Constructs new decommission attribute name value pair
+     *
+     * @param attributeName   attribute name
+     * @param attributeValue attribute value
+     */
+    public DecommissionAttribute(String attributeName, String attributeValue) {
+        this.attributeName = attributeName;
+        this.attributeValue = attributeValue;
+    }
+
+    /**
+     * Returns attribute name
+     *
+     * @return attributeName
+     */
+    public String attributeName() {
+        return this.attributeName;
+    }
+
+    /**
+     * Returns attribute value
+     *
+     * @return attributeValue
+     */
+    public String attributeValue() {
+        return this.attributeValue;
+    }
+
+    public DecommissionAttribute(StreamInput in) throws IOException {
+        attributeName = in.readString();
+        attributeValue = in.readString();
+    }
+
+    /**
+     * Writes decommission attribute name value to stream output
+     *
+     * @param out stream output
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(attributeName);
+        out.writeString(attributeValue);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        DecommissionAttribute that = (DecommissionAttribute) o;
+
+        if (!attributeName.equals(that.attributeName)) return false;
+        return attributeValue.equals(that.attributeValue);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributeName, attributeValue);
+    }
+
+    @Override
+    public String toString() {
+        return "DecommissionAttribute{" + "attributeName='" + attributeName + '\'' + ", attributeValue='" + attributeValue + '\'' + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttributeMetadata.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttributeMetadata.java
new file mode 100644
index 0000000000000..3df807a4f94d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionAttributeMetadata.java
@@ -0,0 +1,287 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.Version;
+import org.opensearch.cluster.AbstractNamedDiffable;
+import org.opensearch.cluster.NamedDiff;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.Metadata.Custom;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.EnumSet;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Contains metadata about decommission attribute
+ *
+ * @opensearch.internal
+ */
+public class DecommissionAttributeMetadata extends AbstractNamedDiffable<Custom> implements Custom {
+
+    public static final String TYPE = "decommissionedAttribute";
+
+    private final DecommissionAttribute decommissionAttribute;
+    private DecommissionStatus status;
+    private String requestID;
+    public static final String attributeType = "awareness";
+
+    /**
+     * Constructs new decommission attribute metadata with given status
+     *
+     * @param decommissionAttribute attribute details
+     * @param status                current status of the attribute decommission
+     */
+    public DecommissionAttributeMetadata(DecommissionAttribute decommissionAttribute, DecommissionStatus status, String requestId) {
+        this.decommissionAttribute = decommissionAttribute;
+        this.status = status;
+        this.requestID = requestId;
+    }
+
+    /**
+     * Constructs new decommission attribute metadata with status as {@link DecommissionStatus#INIT} and request id
+     *
+     * @param decommissionAttribute attribute details
+     */
+    public DecommissionAttributeMetadata(DecommissionAttribute decommissionAttribute, String requestID) {
+        this(decommissionAttribute, DecommissionStatus.INIT, requestID);
+    }
+
+    /**
+     * Returns the current decommissioned attribute
+     *
+     * @return decommissioned attributes
+     */
+    public DecommissionAttribute decommissionAttribute() {
+        return this.decommissionAttribute;
+    }
+
+    /**
+     * Returns the current status of the attribute decommission
+     *
+     * @return attribute type
+     */
+    public DecommissionStatus status() {
+        return this.status;
+    }
+
+    /**
+     * Returns the request id of the decommission
+     *
+     * @return request id
+     */
+    public String requestID() {
+        return this.requestID;
+    }
+
+    /**
+     * Returns instance of the metadata with updated status
+     * @param newStatus status to be updated with
+     */
+    // synchronized is strictly speaking not needed (this is called by a single thread), but just to be safe
+    public synchronized void validateNewStatus(DecommissionStatus newStatus) {
+        // if the current status is the expected status already or new status is FAILED, we let the check pass
+        if (newStatus.equals(status) || newStatus.equals(DecommissionStatus.FAILED)) {
+            return;
+        }
+        // We don't expect that INIT will be new status, as it is registered only when starting the decommission action
+        switch (newStatus) {
+            case DRAINING:
+                validateStatus(Set.of(DecommissionStatus.INIT), newStatus);
+                break;
+            case IN_PROGRESS:
+                validateStatus(Set.of(DecommissionStatus.DRAINING, DecommissionStatus.INIT), newStatus);
+                break;
+            case SUCCESSFUL:
+                validateStatus(Set.of(DecommissionStatus.IN_PROGRESS), newStatus);
+                break;
+            default:
+                throw new IllegalArgumentException(
+                    "illegal decommission status [" + newStatus.status() + "] requested for updating metadata"
+                );
+        }
+    }
+
+    private void validateStatus(Set<DecommissionStatus> expectedStatuses, DecommissionStatus next) {
+        if (expectedStatuses.contains(status) == false) {
+            assert false : "can't move decommission status to ["
+                + next
+                + "]. current status: ["
+                + status
+                + "] (allowed statuses ["
+                + expectedStatuses
+                + "])";
+            throw new IllegalStateException(
+                "can't move decommission status to [" + next + "]. current status: [" + status + "] (expected [" + expectedStatuses + "])"
+            );
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        DecommissionAttributeMetadata that = (DecommissionAttributeMetadata) o;
+
+        if (!status.equals(that.status)) return false;
+        if (!requestID.equals(that.requestID)) return false;
+        return decommissionAttribute.equals(that.decommissionAttribute);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributeType, decommissionAttribute, status, requestID);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public String getWriteableName() {
+        return TYPE;
+    }
+
+    @Override
+    public Version getMinimalSupportedVersion() {
+        return Version.V_2_4_0;
+    }
+
+    public DecommissionAttributeMetadata(StreamInput in) throws IOException {
+        this.decommissionAttribute = new DecommissionAttribute(in);
+        this.status = DecommissionStatus.fromString(in.readString());
+        this.requestID = in.readString();
+    }
+
+    public static NamedDiff<Custom> readDiffFrom(StreamInput in) throws IOException {
+        return readDiffFrom(Custom.class, TYPE, in);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        decommissionAttribute.writeTo(out);
+        out.writeString(status.status());
+        out.writeString(requestID);
+    }
+
+    public static DecommissionAttributeMetadata fromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token;
+        DecommissionAttribute decommissionAttribute = null;
+        DecommissionStatus status = null;
+        String requestID = null;
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                String currentFieldName = parser.currentName();
+                if (attributeType.equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                        throw new OpenSearchParseException(
+                            "failed to parse decommission attribute type [{}], expected object",
+                            attributeType
+                        );
+                    }
+                    token = parser.nextToken();
+                    if (token != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            String fieldName = parser.currentName();
+                            String value;
+                            token = parser.nextToken();
+                            if (token == XContentParser.Token.VALUE_STRING) {
+                                value = parser.text();
+                            } else {
+                                throw new OpenSearchParseException(
+                                    "failed to parse attribute [{}], expected string for attribute value",
+                                    fieldName
+                                );
+                            }
+                            decommissionAttribute = new DecommissionAttribute(fieldName, value);
+                            parser.nextToken();
+                        } else {
+                            throw new OpenSearchParseException("failed to parse attribute type [{}], unexpected type", attributeType);
+                        }
+                    } else {
+                        throw new OpenSearchParseException("failed to parse attribute type [{}]", attributeType);
+                    }
+                } else if ("status".equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                        throw new OpenSearchParseException(
+                            "failed to parse status of decommissioning, expected string but found unknown type"
+                        );
+                    }
+                    status = DecommissionStatus.fromString(parser.text());
+                } else if ("requestID".equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                        throw new OpenSearchParseException(
+                            "failed to parse status of decommissioning, expected string but found unknown type"
+                        );
+                    }
+                    requestID = parser.text();
+                } else {
+                    throw new OpenSearchParseException(
+                        "unknown field found [{}], failed to parse the decommission attribute",
+                        currentFieldName
+                    );
+                }
+            }
+        }
+        return new DecommissionAttributeMetadata(decommissionAttribute, status, requestID);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        toXContent(decommissionAttribute, status, requestID, attributeType, builder, params);
+        return builder;
+    }
+
+    @Override
+    public EnumSet<Metadata.XContentContext> context() {
+        return Metadata.API_AND_GATEWAY;
+    }
+
+    /**
+     * @param decommissionAttribute decommission attribute
+     * @param status                decommission  status
+     * @param attributeType         attribute type
+     * @param builder               XContent builder
+     * @param params                serialization parameters
+     */
+    public static void toXContent(
+        DecommissionAttribute decommissionAttribute,
+        DecommissionStatus status,
+        String requestID,
+        String attributeType,
+        XContentBuilder builder,
+        ToXContent.Params params
+    ) throws IOException {
+        builder.startObject(attributeType);
+        builder.field(decommissionAttribute.attributeName(), decommissionAttribute.attributeValue());
+        builder.endObject();
+        builder.field("status", status.status());
+        builder.field("requestID", requestID);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionController.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionController.java
new file mode 100644
index 0000000000000..fec313b4b0b73
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionController.java
@@ -0,0 +1,263 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchTimeoutException;
+import org.opensearch.action.admin.cluster.node.stats.NodeStats;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsAction;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
+import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateObserver;
+import org.opensearch.cluster.ClusterStateTaskConfig;
+import org.opensearch.cluster.ClusterStateTaskListener;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.coordination.NodeRemovalClusterStateTaskExecutor;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.http.HttpStats;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.clearExclusionsAndGetState;
+
+/**
+ * Helper controller class to remove list of nodes from the cluster and update status
+ *
+ * @opensearch.internal
+ */
+
+public class DecommissionController {
+
+    private static final Logger logger = LogManager.getLogger(DecommissionController.class);
+
+    private final NodeRemovalClusterStateTaskExecutor nodeRemovalExecutor;
+    private final ClusterService clusterService;
+    private final TransportService transportService;
+    private final ThreadPool threadPool;
+
+    DecommissionController(
+        ClusterService clusterService,
+        TransportService transportService,
+        AllocationService allocationService,
+        ThreadPool threadPool
+    ) {
+        this.clusterService = clusterService;
+        this.transportService = transportService;
+        this.nodeRemovalExecutor = new NodeRemovalClusterStateTaskExecutor(allocationService, logger);
+        this.threadPool = threadPool;
+    }
+
+    /**
+     * This method triggers batch of tasks for nodes to be decommissioned using executor {@link NodeRemovalClusterStateTaskExecutor}
+     * Once the tasks are submitted, it waits for an expected cluster state to guarantee
+     * that the expected decommissioned nodes are removed from the cluster
+     *
+     * @param nodesToBeDecommissioned set of the node to be decommissioned
+     * @param reason reason of removal
+     * @param timeout timeout for the request
+     * @param nodesRemovedListener callback for the success or failure
+     */
+    public synchronized void removeDecommissionedNodes(
+        Set<DiscoveryNode> nodesToBeDecommissioned,
+        String reason,
+        TimeValue timeout,
+        ActionListener<Void> nodesRemovedListener
+    ) {
+        final Map<NodeRemovalClusterStateTaskExecutor.Task, ClusterStateTaskListener> nodesDecommissionTasks = new LinkedHashMap<>(
+            nodesToBeDecommissioned.size()
+        );
+        nodesToBeDecommissioned.forEach(discoveryNode -> {
+            final NodeRemovalClusterStateTaskExecutor.Task task = new NodeRemovalClusterStateTaskExecutor.Task(discoveryNode, reason);
+            nodesDecommissionTasks.put(task, nodeRemovalExecutor);
+        });
+
+        logger.info("submitting state update task to remove [{}] nodes due to decommissioning", nodesToBeDecommissioned.toString());
+        clusterService.submitStateUpdateTasks(
+            "node-decommissioned",
+            nodesDecommissionTasks,
+            ClusterStateTaskConfig.build(Priority.URGENT),
+            nodeRemovalExecutor
+        );
+
+        Predicate<ClusterState> allDecommissionedNodesRemovedPredicate = clusterState -> {
+            Set<DiscoveryNode> intersection = Arrays.stream(clusterState.nodes().getNodes().values().toArray(new DiscoveryNode[0]))
+                .collect(Collectors.toSet());
+            intersection.retainAll(nodesToBeDecommissioned);
+            return intersection.size() == 0;
+        };
+
+        final ClusterStateObserver observer = new ClusterStateObserver(clusterService, timeout, logger, threadPool.getThreadContext());
+
+        final ClusterStateObserver.Listener removalListener = new ClusterStateObserver.Listener() {
+            @Override
+            public void onNewClusterState(ClusterState state) {
+                logger.info("successfully removed all decommissioned nodes [{}] from the cluster", nodesToBeDecommissioned.toString());
+                nodesRemovedListener.onResponse(null);
+            }
+
+            @Override
+            public void onClusterServiceClose() {
+                logger.warn(
+                    "cluster service closed while waiting for removal of decommissioned nodes [{}]",
+                    nodesToBeDecommissioned.toString()
+                );
+            }
+
+            @Override
+            public void onTimeout(TimeValue timeout) {
+                logger.info(
+                    "timed out [{}] while waiting for removal of decommissioned nodes [{}]",
+                    timeout.toString(),
+                    nodesToBeDecommissioned.toString()
+                );
+                nodesRemovedListener.onFailure(
+                    new OpenSearchTimeoutException(
+                        "timed out [{}] while waiting for removal of decommissioned nodes [{}]",
+                        timeout.toString(),
+                        nodesToBeDecommissioned.toString()
+                    )
+                );
+            }
+        };
+
+        if (allDecommissionedNodesRemovedPredicate.test(clusterService.getClusterApplierService().state())) {
+            removalListener.onNewClusterState(clusterService.getClusterApplierService().state());
+        } else {
+            observer.waitForNextChange(removalListener, allDecommissionedNodesRemovedPredicate);
+        }
+    }
+
+    /**
+     * This method updates the status in the currently registered metadata.
+     *
+     * @param decommissionStatus status to update decommission metadata with
+     * @param listener listener for response and failure
+     */
+    public void updateMetadataWithDecommissionStatus(DecommissionStatus decommissionStatus, ActionListener<DecommissionStatus> listener) {
+        clusterService.submitStateUpdateTask("update-decommission-status", new ClusterStateUpdateTask(Priority.URGENT) {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                DecommissionAttributeMetadata decommissionAttributeMetadata = currentState.metadata().decommissionAttributeMetadata();
+                assert decommissionAttributeMetadata != null && decommissionAttributeMetadata.decommissionAttribute() != null;
+                logger.info(
+                    "attempting to update current decommission status [{}] with expected status [{}]",
+                    decommissionAttributeMetadata.status(),
+                    decommissionStatus
+                );
+                // validateNewStatus can throw IllegalStateException if the sequence of update is not valid
+                decommissionAttributeMetadata.validateNewStatus(decommissionStatus);
+                decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+                    decommissionAttributeMetadata.decommissionAttribute(),
+                    decommissionStatus,
+                    decommissionAttributeMetadata.requestID()
+                );
+                ClusterState newState = ClusterState.builder(currentState)
+                    .metadata(Metadata.builder(currentState.metadata()).decommissionAttributeMetadata(decommissionAttributeMetadata))
+                    .build();
+
+                // For terminal status we will go ahead and clear any exclusion that was added as part of decommission action
+                if (decommissionStatus.equals(DecommissionStatus.SUCCESSFUL) || decommissionStatus.equals(DecommissionStatus.FAILED)) {
+                    newState = clearExclusionsAndGetState(newState);
+                }
+                return newState;
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                listener.onFailure(e);
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                DecommissionAttributeMetadata decommissionAttributeMetadata = newState.metadata().decommissionAttributeMetadata();
+                assert decommissionAttributeMetadata != null;
+                assert decommissionAttributeMetadata.status().equals(decommissionStatus);
+                listener.onResponse(decommissionAttributeMetadata.status());
+            }
+        });
+    }
+
+    private void logActiveConnections(NodesStatsResponse nodesStatsResponse) {
+        if (nodesStatsResponse == null || nodesStatsResponse.getNodes() == null) {
+            logger.info("Node stats response received is null/empty.");
+            return;
+        }
+
+        Map<String, Long> nodeActiveConnectionMap = new HashMap<>();
+        List<NodeStats> responseNodes = nodesStatsResponse.getNodes();
+        for (int i = 0; i < responseNodes.size(); i++) {
+            HttpStats httpStats = responseNodes.get(i).getHttp();
+            DiscoveryNode node = responseNodes.get(i).getNode();
+            nodeActiveConnectionMap.put(node.getId(), httpStats.getServerOpen());
+        }
+        logger.info("Decommissioning node with connections : [{}]", nodeActiveConnectionMap);
+    }
+
+    void getActiveRequestCountOnDecommissionedNodes(Set<DiscoveryNode> decommissionedNodes) {
+        if (decommissionedNodes == null || decommissionedNodes.isEmpty()) {
+            return;
+        }
+        String[] nodes = decommissionedNodes.stream().map(DiscoveryNode::getId).toArray(String[]::new);
+        if (nodes.length == 0) {
+            return;
+        }
+
+        final NodesStatsRequest nodesStatsRequest = new NodesStatsRequest(nodes);
+        nodesStatsRequest.clear();
+        nodesStatsRequest.addMetric(NodesStatsRequest.Metric.HTTP.metricName());
+
+        transportService.sendRequest(
+            transportService.getLocalNode(),
+            NodesStatsAction.NAME,
+            nodesStatsRequest,
+            new TransportResponseHandler<NodesStatsResponse>() {
+                @Override
+                public void handleResponse(NodesStatsResponse response) {
+                    logActiveConnections(response);
+                }
+
+                @Override
+                public void handleException(TransportException exp) {
+                    logger.error("Failure occurred while dumping connection for decommission nodes - ", exp.unwrapCause());
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.SAME;
+                }
+
+                @Override
+                public NodesStatsResponse read(StreamInput in) throws IOException {
+                    return new NodesStatsResponse(in);
+                }
+            }
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionHelper.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionHelper.java
new file mode 100644
index 0000000000000..4cd65e4f32453
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionHelper.java
@@ -0,0 +1,125 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.addExclusionAndGetState;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.resolveVotingConfigExclusionsAndCheckMaximum;
+
+/**
+ * Static helper utilities to execute decommission
+ *
+ * @opensearch.internal
+ */
+public class DecommissionHelper {
+
+    static ClusterState registerDecommissionAttributeInClusterState(
+        ClusterState currentState,
+        DecommissionAttribute decommissionAttribute,
+        String requestID
+    ) {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(decommissionAttribute, requestID);
+        return ClusterState.builder(currentState)
+            .metadata(Metadata.builder(currentState.metadata()).decommissionAttributeMetadata(decommissionAttributeMetadata))
+            .build();
+    }
+
+    static ClusterState deleteDecommissionAttributeInClusterState(ClusterState currentState) {
+        Metadata metadata = currentState.metadata();
+        Metadata.Builder mdBuilder = Metadata.builder(metadata);
+        mdBuilder.removeCustom(DecommissionAttributeMetadata.TYPE);
+        return ClusterState.builder(currentState).metadata(mdBuilder).build();
+    }
+
+    static ClusterState addVotingConfigExclusionsForNodesToBeDecommissioned(
+        ClusterState currentState,
+        Set<String> nodeIdsToBeExcluded,
+        TimeValue decommissionActionTimeout,
+        final int maxVotingConfigExclusions
+    ) {
+        AddVotingConfigExclusionsRequest request = new AddVotingConfigExclusionsRequest(
+            Strings.EMPTY_ARRAY,
+            nodeIdsToBeExcluded.toArray(String[]::new),
+            Strings.EMPTY_ARRAY,
+            decommissionActionTimeout
+        );
+        Set<VotingConfigExclusion> resolvedExclusion = resolveVotingConfigExclusionsAndCheckMaximum(
+            request,
+            currentState,
+            maxVotingConfigExclusions
+        );
+        return addExclusionAndGetState(currentState, resolvedExclusion, maxVotingConfigExclusions);
+    }
+
+    static Set<DiscoveryNode> filterNodesWithDecommissionAttribute(
+        ClusterState clusterState,
+        DecommissionAttribute decommissionAttribute,
+        boolean onlyClusterManagerNodes
+    ) {
+        Set<DiscoveryNode> nodesWithDecommissionAttribute = new HashSet<>();
+        Iterator<DiscoveryNode> nodesIter = onlyClusterManagerNodes
+            ? clusterState.nodes().getClusterManagerNodes().values().iterator()
+            : clusterState.nodes().getNodes().values().iterator();
+
+        while (nodesIter.hasNext()) {
+            final DiscoveryNode node = nodesIter.next();
+            if (nodeHasDecommissionedAttribute(node, decommissionAttribute)) {
+                nodesWithDecommissionAttribute.add(node);
+            }
+        }
+        return nodesWithDecommissionAttribute;
+    }
+
+    /**
+     * Utility method to check if the node has decommissioned attribute
+     *
+     * @param discoveryNode node to check on
+     * @param decommissionAttribute attribute to be checked with
+     * @return true or false based on whether node has decommissioned attribute
+     */
+    public static boolean nodeHasDecommissionedAttribute(DiscoveryNode discoveryNode, DecommissionAttribute decommissionAttribute) {
+        String nodeAttributeValue = discoveryNode.getAttributes().get(decommissionAttribute.attributeName());
+        return nodeAttributeValue != null && nodeAttributeValue.equals(decommissionAttribute.attributeValue());
+    }
+
+    /**
+     * Utility method to check if the node is commissioned or not
+     *
+     * @param discoveryNode node to check on
+     * @param metadata metadata present current which will be used to check the commissioning status of the node
+     * @return if the node is commissioned or not
+     */
+    public static boolean nodeCommissioned(DiscoveryNode discoveryNode, Metadata metadata) {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = metadata.decommissionAttributeMetadata();
+        if (decommissionAttributeMetadata != null) {
+            DecommissionAttribute decommissionAttribute = decommissionAttributeMetadata.decommissionAttribute();
+            DecommissionStatus status = decommissionAttributeMetadata.status();
+            if (decommissionAttribute != null && status != null) {
+                if (nodeHasDecommissionedAttribute(discoveryNode, decommissionAttribute)
+                    && (status.equals(DecommissionStatus.IN_PROGRESS)
+                        || status.equals(DecommissionStatus.SUCCESSFUL)
+                        || status.equals(DecommissionStatus.DRAINING))) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionService.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionService.java
new file mode 100644
index 0000000000000..7ff894afa21a7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionService.java
@@ -0,0 +1,572 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.OpenSearchTimeoutException;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionResponse;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateObserver;
+import org.opensearch.cluster.ClusterStateObserver.Listener;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.NotClusterManagerException;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+import static org.opensearch.action.admin.cluster.configuration.TransportAddVotingConfigExclusionsAction.MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.clearExclusionsAndGetState;
+import static org.opensearch.cluster.decommission.DecommissionHelper.addVotingConfigExclusionsForNodesToBeDecommissioned;
+import static org.opensearch.cluster.decommission.DecommissionHelper.deleteDecommissionAttributeInClusterState;
+import static org.opensearch.cluster.decommission.DecommissionHelper.filterNodesWithDecommissionAttribute;
+import static org.opensearch.cluster.decommission.DecommissionHelper.nodeHasDecommissionedAttribute;
+import static org.opensearch.cluster.decommission.DecommissionHelper.registerDecommissionAttributeInClusterState;
+import static org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING;
+import static org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING;
+
+/**
+ * Service responsible for entire lifecycle of decommissioning and recommissioning an awareness attribute.
+ * <p>
+ * Whenever a cluster manager initiates operation to decommission an awareness attribute,
+ * the service makes the best attempt to perform the following task -
+ * <ul>
+ * <li>Initiates nodes decommissioning by adding custom metadata with the attribute and state as {@link DecommissionStatus#INIT}</li>
+ * <li>Remove to-be-decommissioned cluster-manager eligible nodes from voting config and wait for its abdication if it is active leader</li>
+ * <li>After the draining timeout, the service triggers nodes decommission. This marks the decommission status as {@link DecommissionStatus#IN_PROGRESS}</li>
+ * <li>Once the decommission is successful, the service clears the voting config and marks the status as {@link DecommissionStatus#SUCCESSFUL}</li>
+ * <li>If service fails at any step, it makes best attempt to mark the status as {@link DecommissionStatus#FAILED} and to clear voting config exclusion</li>
+ * </ul>
+ *
+ * @opensearch.internal
+ */
+public class DecommissionService {
+
+    private static final Logger logger = LogManager.getLogger(DecommissionService.class);
+
+    private final ClusterService clusterService;
+    private final TransportService transportService;
+    private final ThreadPool threadPool;
+    private final DecommissionController decommissionController;
+    private volatile List<String> awarenessAttributes;
+    private volatile Map<String, List<String>> forcedAwarenessAttributes;
+    private volatile int maxVotingConfigExclusions;
+
+    @Inject
+    public DecommissionService(
+        Settings settings,
+        ClusterSettings clusterSettings,
+        ClusterService clusterService,
+        TransportService transportService,
+        ThreadPool threadPool,
+        AllocationService allocationService
+    ) {
+        this.clusterService = clusterService;
+        this.transportService = transportService;
+        this.threadPool = threadPool;
+        this.decommissionController = new DecommissionController(clusterService, transportService, allocationService, threadPool);
+        this.awarenessAttributes = CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING, this::setAwarenessAttributes);
+
+        setForcedAwarenessAttributes(CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(
+            CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING,
+            this::setForcedAwarenessAttributes
+        );
+        maxVotingConfigExclusions = MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MAXIMUM_VOTING_CONFIG_EXCLUSIONS_SETTING, this::setMaxVotingConfigExclusions);
+    }
+
+    private void setAwarenessAttributes(List<String> awarenessAttributes) {
+        this.awarenessAttributes = awarenessAttributes;
+    }
+
+    private void setForcedAwarenessAttributes(Settings forceSettings) {
+        Map<String, List<String>> forcedAwarenessAttributes = new HashMap<>();
+        Map<String, Settings> forceGroups = forceSettings.getAsGroups();
+        for (Map.Entry<String, Settings> entry : forceGroups.entrySet()) {
+            List<String> aValues = entry.getValue().getAsList("values");
+            if (aValues.size() > 0) {
+                forcedAwarenessAttributes.put(entry.getKey(), aValues);
+            }
+        }
+        this.forcedAwarenessAttributes = forcedAwarenessAttributes;
+    }
+
+    private void setMaxVotingConfigExclusions(int maxVotingConfigExclusions) {
+        this.maxVotingConfigExclusions = maxVotingConfigExclusions;
+    }
+
+    /**
+     * Starts the new decommission request and registers the metadata with status as {@link DecommissionStatus#INIT}
+     * Once the status is updated, it tries to exclude to-be-decommissioned cluster manager eligible nodes from Voting Configuration
+     *
+     * @param decommissionRequest request for decommission action
+     * @param listener register decommission listener
+     */
+    public void startDecommissionAction(
+        final DecommissionRequest decommissionRequest,
+        final ActionListener<DecommissionResponse> listener
+    ) {
+        final DecommissionAttribute decommissionAttribute = decommissionRequest.getDecommissionAttribute();
+        // register the metadata with status as INIT as first step
+        clusterService.submitStateUpdateTask("decommission [" + decommissionAttribute + "]", new ClusterStateUpdateTask(Priority.URGENT) {
+            private Set<String> nodeIdsToBeExcluded;
+
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                // validates if correct awareness attributes and forced awareness attribute set to the cluster before starting action
+                validateAwarenessAttribute(decommissionAttribute, awarenessAttributes, forcedAwarenessAttributes);
+                if (decommissionRequest.requestID() == null) {
+                    decommissionRequest.setRequestID(UUIDs.randomBase64UUID());
+                }
+                DecommissionAttributeMetadata decommissionAttributeMetadata = currentState.metadata().decommissionAttributeMetadata();
+                // check that request is eligible to proceed and attribute is weighed away
+                ensureEligibleRequest(decommissionAttributeMetadata, decommissionRequest);
+                ensureToBeDecommissionedAttributeWeighedAway(currentState, decommissionAttribute);
+
+                ClusterState newState = registerDecommissionAttributeInClusterState(
+                    currentState,
+                    decommissionAttribute,
+                    decommissionRequest.requestID()
+                );
+                // add all 'to-be-decommissioned' cluster manager eligible nodes to voting config exclusion
+                nodeIdsToBeExcluded = filterNodesWithDecommissionAttribute(currentState, decommissionAttribute, true).stream()
+                    .map(DiscoveryNode::getId)
+                    .collect(Collectors.toSet());
+                logger.info(
+                    "resolved cluster manager eligible nodes [{}] that should be added to voting config exclusion",
+                    nodeIdsToBeExcluded.toString()
+                );
+                newState = addVotingConfigExclusionsForNodesToBeDecommissioned(
+                    newState,
+                    nodeIdsToBeExcluded,
+                    TimeValue.timeValueSeconds(120), // TODO - update it with request timeout
+                    maxVotingConfigExclusions
+                );
+                logger.debug(
+                    "registering decommission metadata [{}] to execute action",
+                    newState.metadata().decommissionAttributeMetadata().toString()
+                );
+                return newState;
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error(
+                    () -> new ParameterizedMessage(
+                        "failed to start decommission action for attribute [{}]",
+                        decommissionAttribute.toString()
+                    ),
+                    e
+                );
+                listener.onFailure(e);
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                DecommissionAttributeMetadata decommissionAttributeMetadata = newState.metadata().decommissionAttributeMetadata();
+                assert decommissionAttribute.equals(decommissionAttributeMetadata.decommissionAttribute());
+                assert decommissionAttributeMetadata.status().equals(DecommissionStatus.INIT);
+                assert decommissionAttributeMetadata.requestID().equals(decommissionRequest.requestID());
+                assert newState.getVotingConfigExclusions()
+                    .stream()
+                    .map(CoordinationMetadata.VotingConfigExclusion::getNodeId)
+                    .collect(Collectors.toSet())
+                    .containsAll(nodeIdsToBeExcluded);
+                logger.debug(
+                    "registered decommission metadata for attribute [{}] with status [{}]",
+                    decommissionAttributeMetadata.decommissionAttribute(),
+                    decommissionAttributeMetadata.status()
+                );
+
+                final ClusterStateObserver observer = new ClusterStateObserver(
+                    clusterService,
+                    TimeValue.timeValueSeconds(120), // TODO - update it with request timeout
+                    logger,
+                    threadPool.getThreadContext()
+                );
+
+                final Predicate<ClusterState> allNodesRemovedAndAbdicated = clusterState -> {
+                    final Set<String> votingConfigNodeIds = clusterState.getLastCommittedConfiguration().getNodeIds();
+                    return nodeIdsToBeExcluded.stream().noneMatch(votingConfigNodeIds::contains)
+                        && clusterState.nodes().getClusterManagerNodeId() != null
+                        && nodeIdsToBeExcluded.contains(clusterState.nodes().getClusterManagerNodeId()) == false;
+                };
+
+                final Listener clusterStateListener = new Listener() {
+                    @Override
+                    public void onNewClusterState(ClusterState state) {
+                        logger.info(
+                            "successfully removed decommissioned cluster manager eligible nodes [{}] from voting config ",
+                            nodeIdsToBeExcluded.toString()
+                        );
+                        if (state.nodes().isLocalNodeElectedClusterManager()) {
+                            if (nodeHasDecommissionedAttribute(clusterService.localNode(), decommissionAttribute)) {
+                                // this is an unexpected state, as after exclusion of nodes having decommission attribute,
+                                // this local node shouldn't have had the decommission attribute. Will send the failure response to the user
+                                String errorMsg =
+                                    "unexpected state encountered [local node is to-be-decommissioned leader] while executing decommission request";
+                                logger.error(errorMsg);
+                                // will go ahead and clear the voting config and mark the status as failed
+                                decommissionController.updateMetadataWithDecommissionStatus(
+                                    DecommissionStatus.FAILED,
+                                    statusUpdateListener()
+                                );
+                                listener.onFailure(new IllegalStateException(errorMsg));
+                            } else {
+                                logger.info("will proceed to drain decommissioned nodes as local node is eligible to process the request");
+                                // we are good here to send the response now as the request is processed by an eligible active leader
+                                // and to-be-decommissioned cluster manager is no more part of Voting Configuration
+                                listener.onResponse(new DecommissionResponse(true));
+                                drainNodesWithDecommissionedAttribute(decommissionRequest);
+                            }
+                        } else {
+                            // explicitly calling listener.onFailure with NotClusterManagerException as the local node is not leader
+                            // this will ensures that request is retried until cluster manager times out
+                            logger.info(
+                                "local node is not eligible to process the request, "
+                                    + "throwing NotClusterManagerException to attempt a retry on an eligible node"
+                            );
+                            listener.onFailure(
+                                new NotClusterManagerException(
+                                    "node ["
+                                        + transportService.getLocalNode().toString()
+                                        + "] not eligible to execute decommission request. Will retry until timeout."
+                                )
+                            );
+                        }
+                    }
+
+                    @Override
+                    public void onClusterServiceClose() {
+                        String errorMsg = "cluster service closed while waiting for abdication of to-be-decommissioned leader";
+                        logger.error(errorMsg);
+                        listener.onFailure(new DecommissioningFailedException(decommissionAttribute, errorMsg));
+                    }
+
+                    @Override
+                    public void onTimeout(TimeValue timeout) {
+                        String errorMsg = "timed out ["
+                            + timeout.toString()
+                            + "] while removing to-be-decommissioned cluster manager eligible nodes ["
+                            + nodeIdsToBeExcluded.toString()
+                            + "] from voting config";
+                        logger.error(errorMsg);
+                        listener.onFailure(new OpenSearchTimeoutException(errorMsg));
+                        // will go ahead and clear the voting config and mark the status as failed
+                        decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.FAILED, statusUpdateListener());
+                    }
+                };
+
+                // In case the cluster state is already processed even before this code is executed
+                // therefore testing first before attaching the listener
+                if (allNodesRemovedAndAbdicated.test(newState)) {
+                    clusterStateListener.onNewClusterState(newState);
+                } else {
+                    logger.debug("waiting to abdicate to-be-decommissioned leader");
+                    observer.waitForNextChange(clusterStateListener, allNodesRemovedAndAbdicated); // TODO add request timeout here
+                }
+            }
+        });
+    }
+
+    // TODO - after registering the new status check if any node which is not excluded still present in decommissioned zone. If yes, start
+    // the action again (retry)
+    void drainNodesWithDecommissionedAttribute(DecommissionRequest decommissionRequest) {
+        ClusterState state = clusterService.getClusterApplierService().state();
+        assert state.metadata().decommissionAttributeMetadata().requestID().equals(decommissionRequest.requestID());
+        Set<DiscoveryNode> decommissionedNodes = filterNodesWithDecommissionAttribute(
+            state,
+            decommissionRequest.getDecommissionAttribute(),
+            false
+        );
+
+        if (decommissionRequest.isNoDelay()) {
+            // Call to fail the decommission nodes
+            failDecommissionedNodes(decommissionedNodes, decommissionRequest.getDecommissionAttribute());
+        } else {
+            decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.DRAINING, new ActionListener<>() {
+                @Override
+                public void onResponse(DecommissionStatus status) {
+                    logger.info("updated the decommission status to [{}]", status);
+                    // set the weights
+                    scheduleNodesDecommissionOnTimeout(decommissionedNodes, decommissionRequest.getDelayTimeout());
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(
+                        () -> new ParameterizedMessage(
+                            "failed to update decommission status for attribute [{}] to [{}]",
+                            decommissionRequest.getDecommissionAttribute().toString(),
+                            DecommissionStatus.DRAINING
+                        ),
+                        e
+                    );
+                    // This decommission state update call will most likely fail as the state update call to 'DRAINING'
+                    // failed. But attempting it anyways as FAILED update might still pass as it doesn't have dependency on
+                    // the current state
+                    decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.FAILED, statusUpdateListener());
+                }
+            });
+        }
+    }
+
+    void scheduleNodesDecommissionOnTimeout(Set<DiscoveryNode> decommissionedNodes, TimeValue timeoutForNodeDraining) {
+        ClusterState state = clusterService.getClusterApplierService().state();
+        DecommissionAttributeMetadata decommissionAttributeMetadata = state.metadata().decommissionAttributeMetadata();
+        if (decommissionAttributeMetadata == null) {
+            return;
+        }
+        assert decommissionAttributeMetadata.status().equals(DecommissionStatus.DRAINING)
+            : "Unexpected status encountered while decommissioning nodes.";
+
+        // This method ensures no matter what, we always exit from this function after clearing the voting config exclusion
+        DecommissionAttribute decommissionAttribute = decommissionAttributeMetadata.decommissionAttribute();
+
+        // Wait for timeout to happen. Log the active connection before decommissioning of nodes.
+        transportService.getThreadPool().schedule(() -> {
+            // Log active connections.
+            decommissionController.getActiveRequestCountOnDecommissionedNodes(decommissionedNodes);
+            // Call to fail the decommission nodes
+            failDecommissionedNodes(decommissionedNodes, decommissionAttribute);
+        }, timeoutForNodeDraining, ThreadPool.Names.GENERIC);
+    }
+
+    private void failDecommissionedNodes(Set<DiscoveryNode> decommissionedNodes, DecommissionAttribute decommissionAttribute) {
+
+        // Weighing away is complete. We have allowed the nodes to be drained. Let's move decommission status to IN_PROGRESS.
+        decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.IN_PROGRESS, new ActionListener<>() {
+            @Override
+            public void onResponse(DecommissionStatus status) {
+                logger.info("updated the decommission status to [{}]", status);
+                // execute nodes decommissioning
+                decommissionController.removeDecommissionedNodes(
+                    decommissionedNodes,
+                    "nodes-decommissioned",
+                    TimeValue.timeValueSeconds(120L),
+                    new ActionListener<Void>() {
+                        @Override
+                        public void onResponse(Void unused) {
+                            // will clear the voting config exclusion and mark the status as successful
+                            decommissionController.updateMetadataWithDecommissionStatus(
+                                DecommissionStatus.SUCCESSFUL,
+                                statusUpdateListener()
+                            );
+                        }
+
+                        @Override
+                        public void onFailure(Exception e) {
+                            // will go ahead and clear the voting config and mark the status as failed
+                            decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.FAILED, statusUpdateListener());
+                        }
+                    }
+                );
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error(
+                    () -> new ParameterizedMessage(
+                        "failed to update decommission status for attribute [{}] to [{}]",
+                        decommissionAttribute.toString(),
+                        DecommissionStatus.IN_PROGRESS
+                    ),
+                    e
+                );
+                // This decommission state update call will most likely fail as the state update call to 'DRAINING'
+                // failed. But attempting it anyways as FAILED update might still pass as it doesn't have dependency on
+                // the current state
+                decommissionController.updateMetadataWithDecommissionStatus(DecommissionStatus.FAILED, statusUpdateListener());
+            }
+        });
+    }
+
+    private static void validateAwarenessAttribute(
+        final DecommissionAttribute decommissionAttribute,
+        List<String> awarenessAttributes,
+        Map<String, List<String>> forcedAwarenessAttributes
+    ) {
+        String msg = null;
+        if (awarenessAttributes == null) {
+            msg = "awareness attribute not set to the cluster.";
+        } else if (forcedAwarenessAttributes == null) {
+            msg = "forced awareness attribute not set to the cluster.";
+        } else if (awarenessAttributes.contains(decommissionAttribute.attributeName()) == false) {
+            msg = "invalid awareness attribute requested for decommissioning";
+        } else if (forcedAwarenessAttributes.containsKey(decommissionAttribute.attributeName()) == false) {
+            msg = "forced awareness attribute [" + forcedAwarenessAttributes.toString() + "] doesn't have the decommissioning attribute";
+        }
+        // we don't need to check for attributes presence in forced awareness attribute because, weights API ensures that weights are set
+        // for all discovered routing attributes and forced attributes.
+        // So, if the weight is not present for the attribute it could mean its a non routing node (eg. cluster manager)
+        // And in that case, we are ok to proceed with the decommission. A routing node's attribute absence in forced awareness attribute is
+        // a problem elsewhere
+
+        if (msg != null) {
+            throw new DecommissioningFailedException(decommissionAttribute, msg);
+        }
+    }
+
+    private static void ensureToBeDecommissionedAttributeWeighedAway(ClusterState state, DecommissionAttribute decommissionAttribute) {
+        WeightedRoutingMetadata weightedRoutingMetadata = state.metadata().weightedRoutingMetadata();
+        if (weightedRoutingMetadata == null) {
+            throw new DecommissioningFailedException(
+                decommissionAttribute,
+                "no weights are set to the attribute. Please set appropriate weights before triggering decommission action"
+            );
+        }
+        WeightedRouting weightedRouting = weightedRoutingMetadata.getWeightedRouting();
+        if (weightedRouting.attributeName().equals(decommissionAttribute.attributeName()) == false) {
+            throw new DecommissioningFailedException(
+                decommissionAttribute,
+                "no weights are specified to attribute [" + decommissionAttribute.attributeName() + "]"
+            );
+        }
+        // in case the weight is not set for the attribute value, then we know that attribute values was not part of discovered routing node
+        // attribute or forced awareness attribute and in that case, we are ok if the attribute's value weight is not set. But if it's set,
+        // its weight has to be zero
+        Double attributeValueWeight = weightedRouting.weights().get(decommissionAttribute.attributeValue());
+        if (attributeValueWeight != null && attributeValueWeight.equals(0.0) == false) {
+            throw new DecommissioningFailedException(
+                decommissionAttribute,
+                "weight for decommissioned attribute is expected to be [0.0] but found [" + attributeValueWeight + "]"
+            );
+        }
+    }
+
+    private static void ensureEligibleRequest(
+        DecommissionAttributeMetadata decommissionAttributeMetadata,
+        DecommissionRequest decommissionRequest
+    ) {
+        String msg;
+        DecommissionAttribute requestedDecommissionAttribute = decommissionRequest.getDecommissionAttribute();
+        if (decommissionAttributeMetadata != null) {
+            // check if the same attribute is registered and handle it accordingly
+            if (decommissionAttributeMetadata.decommissionAttribute().equals(requestedDecommissionAttribute)) {
+                switch (decommissionAttributeMetadata.status()) {
+                    // for INIT - check if it is eligible internal retry
+                    case INIT:
+                        if (decommissionRequest.requestID().equals(decommissionAttributeMetadata.requestID()) == false) {
+                            throw new DecommissioningFailedException(
+                                requestedDecommissionAttribute,
+                                "same request is already in status [INIT]"
+                            );
+                        }
+                        break;
+                    // for FAILED - we are good to process it again
+                    case FAILED:
+                        break;
+                    case DRAINING:
+                    case IN_PROGRESS:
+                    case SUCCESSFUL:
+                        msg = "same request is already in status [" + decommissionAttributeMetadata.status() + "]";
+                        throw new DecommissioningFailedException(requestedDecommissionAttribute, msg);
+                    default:
+                        throw new IllegalStateException(
+                            "unknown status [" + decommissionAttributeMetadata.status() + "] currently registered in metadata"
+                        );
+                }
+            } else {
+                switch (decommissionAttributeMetadata.status()) {
+                    case SUCCESSFUL:
+                        // one awareness attribute is already decommissioned. We will reject the new request
+                        msg = "one awareness attribute ["
+                            + decommissionAttributeMetadata.decommissionAttribute().toString()
+                            + "] already successfully decommissioned, recommission before triggering another decommission";
+                        throw new DecommissioningFailedException(requestedDecommissionAttribute, msg);
+                    case DRAINING:
+                    case IN_PROGRESS:
+                    case INIT:
+                        // it means the decommission has been initiated or is inflight. In that case, will fail new request
+                        msg = "there's an inflight decommission request for attribute ["
+                            + decommissionAttributeMetadata.decommissionAttribute().toString()
+                            + "] is in progress, cannot process this request";
+                        throw new DecommissioningFailedException(requestedDecommissionAttribute, msg);
+                    case FAILED:
+                        break;
+                    default:
+                        throw new IllegalStateException(
+                            "unknown status [" + decommissionAttributeMetadata.status() + "] currently registered in metadata"
+                        );
+                }
+            }
+        }
+    }
+
+    private ActionListener<DecommissionStatus> statusUpdateListener() {
+        return new ActionListener<>() {
+            @Override
+            public void onResponse(DecommissionStatus status) {
+                logger.info("updated the decommission status to [{}]", status);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("unexpected failure occurred during decommission status update", e);
+            }
+        };
+    }
+
+    public void startRecommissionAction(final ActionListener<DeleteDecommissionStateResponse> listener) {
+        /*
+         * For abandoned requests, we might not really know if it actually restored the exclusion list.
+         * And can land up in cases where even after recommission, exclusions are set(which is unexpected).
+         * And by definition of OpenSearch - Clusters should have no voting configuration exclusions in normal operation.
+         * Once the excluded nodes have stopped, clear the voting configuration exclusions with DELETE /_cluster/voting_config_exclusions.
+         * And hence it is safe to remove the exclusion if any. User should make conscious choice before decommissioning awareness attribute.
+         */
+        clusterService.submitStateUpdateTask("delete-decommission-state", new ClusterStateUpdateTask(Priority.URGENT) {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                ClusterState newState = clearExclusionsAndGetState(currentState);
+                logger.info("Deleting the decommission attribute from the cluster state");
+                newState = deleteDecommissionAttributeInClusterState(newState);
+                return newState;
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error(() -> new ParameterizedMessage("failure during recommission action [{}]", source), e);
+                listener.onFailure(e);
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                logger.info("successfully cleared voting config exclusion and decommissioned attribute");
+                assert newState.metadata().decommissionAttributeMetadata() == null;
+                assert newState.coordinationMetadata().getVotingConfigExclusions().isEmpty();
+                listener.onResponse(new DeleteDecommissionStateResponse(true));
+            }
+        });
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissionStatus.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionStatus.java
new file mode 100644
index 0000000000000..4ca8c3cc4286e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissionStatus.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+/**
+ * An enumeration of the states during decommissioning
+ */
+public enum DecommissionStatus {
+    /**
+     * Decommission process is initiated, and to-be-decommissioned leader is excluded from voting config
+     */
+    INIT("init"),
+    /**
+     * Decommission process is initiated, and the zone is being drained.
+     */
+    DRAINING("draining"),
+
+    /**
+     * Decommission process has started, decommissioned nodes should be removed
+     */
+    IN_PROGRESS("in_progress"),
+    /**
+     * Decommission action completed
+     */
+    SUCCESSFUL("successful"),
+    /**
+     * Decommission request failed
+     */
+    FAILED("failed");
+
+    private final String status;
+
+    DecommissionStatus(String status) {
+        this.status = status;
+    }
+
+    /**
+     * Returns status that represents the decommission state
+     *
+     * @return status
+     */
+    public String status() {
+        return status;
+    }
+
+    /**
+     * Generate decommission status from given string
+     *
+     * @param status status in string
+     * @return status
+     */
+    public static DecommissionStatus fromString(String status) {
+        if (status == null) {
+            throw new IllegalArgumentException("decommission status cannot be null");
+        }
+        if (status.equals(INIT.status())) {
+            return INIT;
+        } else if (status.equals(DRAINING.status())) {
+            return DRAINING;
+        } else if (status.equals(IN_PROGRESS.status())) {
+            return IN_PROGRESS;
+        } else if (status.equals(SUCCESSFUL.status())) {
+            return SUCCESSFUL;
+        } else if (status.equals(FAILED.status())) {
+            return FAILED;
+        }
+        throw new IllegalStateException("Decommission status [" + status + "] not recognized.");
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/DecommissioningFailedException.java b/server/src/main/java/org/opensearch/cluster/decommission/DecommissioningFailedException.java
new file mode 100644
index 0000000000000..6f3b319a543c6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/DecommissioningFailedException.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown whenever a failure occurs in decommission request @{@link DecommissionService}
+ *
+ * @opensearch.internal
+ */
+
+public class DecommissioningFailedException extends OpenSearchException {
+
+    private final DecommissionAttribute decommissionAttribute;
+
+    public DecommissioningFailedException(DecommissionAttribute decommissionAttribute, String msg) {
+        this(decommissionAttribute, msg, null);
+    }
+
+    public DecommissioningFailedException(DecommissionAttribute decommissionAttribute, String msg, Throwable cause) {
+        super("[" + (decommissionAttribute == null ? "_na" : decommissionAttribute.toString()) + "] " + msg, cause);
+        this.decommissionAttribute = decommissionAttribute;
+    }
+
+    public DecommissioningFailedException(StreamInput in) throws IOException {
+        super(in);
+        decommissionAttribute = new DecommissionAttribute(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        decommissionAttribute.writeTo(out);
+    }
+
+    /**
+     * Returns decommission attribute
+     *
+     * @return decommission attribute
+     */
+    public DecommissionAttribute decommissionAttribute() {
+        return decommissionAttribute;
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.BAD_REQUEST;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/NodeDecommissionedException.java b/server/src/main/java/org/opensearch/cluster/decommission/NodeDecommissionedException.java
new file mode 100644
index 0000000000000..ef85335be9a74
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/NodeDecommissionedException.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown if the node is decommissioned by @{@link DecommissionService}
+ * and this nodes needs to be removed from the cluster
+ *
+ * @opensearch.internal
+ */
+public class NodeDecommissionedException extends OpenSearchException {
+
+    public NodeDecommissionedException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    public NodeDecommissionedException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.FAILED_DEPENDENCY;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/decommission/package-info.java b/server/src/main/java/org/opensearch/cluster/decommission/package-info.java
new file mode 100644
index 0000000000000..256c2f22253cc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/decommission/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Decommission lifecycle classes
+ */
+package org.opensearch.cluster.decommission;
diff --git a/server/src/main/java/org/opensearch/cluster/health/ClusterHealthStatus.java b/server/src/main/java/org/opensearch/cluster/health/ClusterHealthStatus.java
index 07a66a3731ff6..5ea482b8b8ffa 100644
--- a/server/src/main/java/org/opensearch/cluster/health/ClusterHealthStatus.java
+++ b/server/src/main/java/org/opensearch/cluster/health/ClusterHealthStatus.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.cluster.health;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Cluster health status
+ *
+ * @opensearch.internal
+ */
 public enum ClusterHealthStatus implements Writeable {
     GREEN((byte) 0),
     YELLOW((byte) 1),
diff --git a/server/src/main/java/org/opensearch/cluster/health/ClusterIndexHealth.java b/server/src/main/java/org/opensearch/cluster/health/ClusterIndexHealth.java
index ffe54e42355f8..0bb762e3ff744 100644
--- a/server/src/main/java/org/opensearch/cluster/health/ClusterIndexHealth.java
+++ b/server/src/main/java/org/opensearch/cluster/health/ClusterIndexHealth.java
@@ -35,15 +35,15 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -54,10 +54,15 @@
 import java.util.Objects;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Cluster Index Health Information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterIndexHealth implements Iterable<ClusterShardHealth>, Writeable, ToXContentFragment {
     private static final String STATUS = "status";
     private static final String NUMBER_OF_SHARDS = "number_of_shards";
diff --git a/server/src/main/java/org/opensearch/cluster/health/ClusterShardHealth.java b/server/src/main/java/org/opensearch/cluster/health/ClusterShardHealth.java
index fc6c6eb4f9bdc..d06e89d9ea170 100644
--- a/server/src/main/java/org/opensearch/cluster/health/ClusterShardHealth.java
+++ b/server/src/main/java/org/opensearch/cluster/health/ClusterShardHealth.java
@@ -37,23 +37,29 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.UnassignedInfo.AllocationStatus;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Locale;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Cluster shard health information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterShardHealth implements Writeable, ToXContentFragment {
     private static final String STATUS = "status";
     private static final String ACTIVE_SHARDS = "active_shards";
@@ -269,7 +275,7 @@ public static ClusterShardHealth fromXContent(XContentParser parser) throws IOEx
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java b/server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java
index c6b214d31707e..15b8c90c5d08f 100644
--- a/server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java
+++ b/server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java
@@ -36,10 +36,10 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -49,11 +49,16 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Cluster state health information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterStateHealth implements Iterable<ClusterIndexHealth>, Writeable {
 
     private final int numberOfNodes;
     private final int numberOfDataNodes;
-    private final boolean hasDiscoveredMaster;
+    private final boolean hasDiscoveredClusterManager;
     private final int activeShards;
     private final int relocatingShards;
     private final int activePrimaryShards;
@@ -81,7 +86,7 @@ public ClusterStateHealth(final ClusterState clusterState) {
     public ClusterStateHealth(final ClusterState clusterState, final String[] concreteIndices) {
         numberOfNodes = clusterState.nodes().getSize();
         numberOfDataNodes = clusterState.nodes().getDataNodes().size();
-        hasDiscoveredMaster = clusterState.nodes().getMasterNodeId() != null;
+        hasDiscoveredClusterManager = clusterState.nodes().getClusterManagerNodeId() != null;
         indices = new HashMap<>();
         for (String index : concreteIndices) {
             IndexRoutingTable indexRoutingTable = clusterState.routingTable().index(index);
@@ -150,9 +155,9 @@ public ClusterStateHealth(final StreamInput in) throws IOException {
         numberOfNodes = in.readVInt();
         numberOfDataNodes = in.readVInt();
         if (in.getVersion().onOrAfter(Version.V_1_0_0)) {
-            hasDiscoveredMaster = in.readBoolean();
+            hasDiscoveredClusterManager = in.readBoolean();
         } else {
-            hasDiscoveredMaster = true;
+            hasDiscoveredClusterManager = true;
         }
         status = ClusterHealthStatus.fromValue(in.readByte());
         int size = in.readVInt();
@@ -175,7 +180,7 @@ public ClusterStateHealth(
         int unassignedShards,
         int numberOfNodes,
         int numberOfDataNodes,
-        boolean hasDiscoveredMaster,
+        boolean hasDiscoveredClusterManager,
         double activeShardsPercent,
         ClusterHealthStatus status,
         Map<String, ClusterIndexHealth> indices
@@ -187,7 +192,7 @@ public ClusterStateHealth(
         this.unassignedShards = unassignedShards;
         this.numberOfNodes = numberOfNodes;
         this.numberOfDataNodes = numberOfDataNodes;
-        this.hasDiscoveredMaster = hasDiscoveredMaster;
+        this.hasDiscoveredClusterManager = hasDiscoveredClusterManager;
         this.activeShardsPercent = activeShardsPercent;
         this.status = status;
         this.indices = indices;
@@ -233,8 +238,14 @@ public double getActiveShardsPercent() {
         return activeShardsPercent;
     }
 
+    public boolean hasDiscoveredClusterManager() {
+        return hasDiscoveredClusterManager;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #hasDiscoveredClusterManager()} */
+    @Deprecated
     public boolean hasDiscoveredMaster() {
-        return hasDiscoveredMaster;
+        return hasDiscoveredClusterManager();
     }
 
     @Override
@@ -252,7 +263,7 @@ public void writeTo(final StreamOutput out) throws IOException {
         out.writeVInt(numberOfNodes);
         out.writeVInt(numberOfDataNodes);
         if (out.getVersion().onOrAfter(Version.V_1_0_0)) {
-            out.writeBoolean(hasDiscoveredMaster);
+            out.writeBoolean(hasDiscoveredClusterManager);
         }
         out.writeByte(status.value());
         out.writeVInt(indices.size());
@@ -269,8 +280,8 @@ public String toString() {
             + numberOfNodes
             + ", numberOfDataNodes="
             + numberOfDataNodes
-            + ", hasDiscoveredMaster="
-            + hasDiscoveredMaster
+            + ", hasDiscoveredClusterManager="
+            + hasDiscoveredClusterManager
             + ", activeShards="
             + activeShards
             + ", relocatingShards="
@@ -297,7 +308,7 @@ public boolean equals(Object o) {
         ClusterStateHealth that = (ClusterStateHealth) o;
         return numberOfNodes == that.numberOfNodes
             && numberOfDataNodes == that.numberOfDataNodes
-            && hasDiscoveredMaster == that.hasDiscoveredMaster
+            && hasDiscoveredClusterManager == that.hasDiscoveredClusterManager
             && activeShards == that.activeShards
             && relocatingShards == that.relocatingShards
             && activePrimaryShards == that.activePrimaryShards
@@ -313,7 +324,7 @@ public int hashCode() {
         return Objects.hash(
             numberOfNodes,
             numberOfDataNodes,
-            hasDiscoveredMaster,
+            hasDiscoveredClusterManager,
             activeShards,
             relocatingShards,
             activePrimaryShards,
diff --git a/server/src/main/java/org/opensearch/cluster/health/package-info.java b/server/src/main/java/org/opensearch/cluster/health/package-info.java
new file mode 100644
index 0000000000000..f022210548cfe
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/health/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Health Foundation classes. */
+package org.opensearch.cluster.health;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/AliasAction.java b/server/src/main/java/org/opensearch/cluster/metadata/AliasAction.java
index eede77917a2fd..47c6cad04343e 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/AliasAction.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/AliasAction.java
@@ -34,10 +34,12 @@
 
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /**
  * Individual operation to perform on the cluster state as part of an {@link IndicesAliasesRequest}.
+ *
+ * @opensearch.internal
  */
 public abstract class AliasAction {
     private final String index;
@@ -74,6 +76,8 @@ public String getIndex() {
 
     /**
      * Validate a new alias.
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface NewAliasValidator {
@@ -82,6 +86,8 @@ public interface NewAliasValidator {
 
     /**
      * Operation to add an alias to an index.
+     *
+     * @opensearch.internal
      */
     public static class Add extends AliasAction {
         private final String alias;
@@ -132,6 +138,18 @@ public String getAlias() {
             return alias;
         }
 
+        public String getFilter() {
+            return filter;
+        }
+
+        public String getSearchRouting() {
+            return searchRouting;
+        }
+
+        public String getIndexRouting() {
+            return indexRouting;
+        }
+
         public Boolean writeIndex() {
             return writeIndex;
         }
@@ -172,6 +190,8 @@ boolean apply(NewAliasValidator aliasValidator, Metadata.Builder metadata, Index
 
     /**
      * Operation to remove an alias from an index.
+     *
+     * @opensearch.internal
      */
     public static class Remove extends AliasAction {
         private final String alias;
@@ -218,6 +238,8 @@ boolean apply(NewAliasValidator aliasValidator, Metadata.Builder metadata, Index
     /**
      * Operation to remove an index. This is an "alias action" because it allows us to remove an index at the same time as we remove add an
      * alias to replace it.
+     *
+     * @opensearch.internal
      */
     public static class RemoveIndex extends AliasAction {
         public RemoveIndex(String index) {
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/AliasMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/AliasMetadata.java
index e6deb22477bae..0f97667f8fbed 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/AliasMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/AliasMetadata.java
@@ -37,18 +37,19 @@
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -58,6 +59,11 @@
 
 import static java.util.Collections.emptySet;
 
+/**
+ * Metadata for index aliases
+ *
+ * @opensearch.internal
+ */
 public class AliasMetadata extends AbstractDiffable<AliasMetadata> implements ToXContentFragment {
 
     private final String alias;
@@ -262,7 +268,7 @@ public static Diff<AliasMetadata> readDiffFrom(StreamInput in) throws IOExceptio
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     @Override
@@ -271,6 +277,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder of alias metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final String alias;
@@ -301,11 +312,11 @@ public Builder filter(CompressedXContent filter) {
         }
 
         public Builder filter(String filter) {
-            if (!Strings.hasLength(filter)) {
+            if (Strings.hasLength(filter) == false) {
                 this.filter = null;
                 return this;
             }
-            return filter(XContentHelper.convertToMap(XContentFactory.xContent(filter), filter, true));
+            return filter(XContentHelper.convertToMap(MediaTypeRegistry.xContent(filter).xContent(), filter, true));
         }
 
         public Builder filter(Map<String, Object> filter) {
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/AliasValidator.java b/server/src/main/java/org/opensearch/cluster/metadata/AliasValidator.java
index c024358c5d1d3..db7f38518b80d 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/AliasValidator.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/AliasValidator.java
@@ -34,13 +34,13 @@
 
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.Rewriteable;
@@ -55,6 +55,8 @@
 /**
  * Validator for an alias, to be used before adding an alias to the index metadata
  * and make sure the alias is valid
+ *
+ * @opensearch.internal
  */
 public class AliasValidator {
     /**
@@ -78,7 +80,7 @@ public void validateAliasMetadata(AliasMetadata aliasMetadata, String index, Met
     /**
      * Allows to partially validate an alias, without knowing which index it'll get applied to.
      * Useful with index templates containing aliases. Checks also that it is possible to parse
-     * the alias filter via {@link org.opensearch.common.xcontent.XContentParser},
+     * the alias filter via {@link XContentParser},
      * without validating it as a filter though.
      * @throws IllegalArgumentException if the alias is not valid
      */
@@ -86,7 +88,7 @@ public void validateAliasStandalone(Alias alias) {
         validateAliasStandalone(alias.name(), alias.indexRouting());
         if (Strings.hasLength(alias.filter())) {
             try {
-                XContentHelper.convertToMap(XContentFactory.xContent(alias.filter()), alias.filter(), false);
+                XContentHelper.convertToMap(MediaTypeRegistry.xContent(alias.filter()).xContent(), alias.filter(), false);
             } catch (Exception e) {
                 throw new IllegalArgumentException("failed to parse filter for alias [" + alias.name() + "]", e);
             }
@@ -99,7 +101,7 @@ public void validateAliasStandalone(Alias alias) {
     public void validateAlias(String alias, String index, @Nullable String indexRouting, Function<String, IndexMetadata> indexLookup) {
         validateAliasStandalone(alias, indexRouting);
 
-        if (!Strings.hasText(index)) {
+        if (Strings.hasText(index) == false) {
             throw new IllegalArgumentException("index name is required");
         }
 
@@ -132,7 +134,8 @@ public void validateAliasFilter(
     ) {
         assert queryShardContext != null;
         try (
-            XContentParser parser = XContentFactory.xContent(filter)
+            XContentParser parser = MediaTypeRegistry.xContent(filter)
+                .xContent()
                 .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, filter)
         ) {
             validateAliasFilter(parser, queryShardContext);
@@ -156,7 +159,7 @@ public void validateAliasFilter(
 
         try (
             InputStream inputStream = filter.streamInput();
-            XContentParser parser = XContentFactory.xContentType(inputStream)
+            XContentParser parser = MediaTypeRegistry.xContentType(inputStream)
                 .xContent()
                 .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, filter.streamInput())
         ) {
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/AutoExpandReplicas.java b/server/src/main/java/org/opensearch/cluster/metadata/AutoExpandReplicas.java
index a7538d0a5b4f8..6acae8cca59fd 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/AutoExpandReplicas.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/AutoExpandReplicas.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
@@ -52,6 +51,8 @@
  * This class acts as a functional wrapper around the {@code index.auto_expand_replicas} setting.
  * This setting or rather it's value is expanded into a min and max value which requires special handling
  * based on the number of datanodes in the cluster. This class handles all the parsing and streamlines the access to these values.
+ *
+ * @opensearch.internal
  */
 public final class AutoExpandReplicas {
     // the value we recognize in the "max" position to mean all the nodes
@@ -132,13 +133,21 @@ int getMaxReplicas(int numDataNodes) {
         return Math.min(maxReplicas, numDataNodes - 1);
     }
 
+    public int getMaxReplicas() {
+        return maxReplicas;
+    }
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+
     private OptionalInt getDesiredNumberOfReplicas(IndexMetadata indexMetadata, RoutingAllocation allocation) {
         if (enabled) {
             int numMatchingDataNodes = 0;
             // Only start using new logic once all nodes are migrated to 7.6.0, avoiding disruption during an upgrade
             if (allocation.nodes().getMinNodeVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
-                for (ObjectCursor<DiscoveryNode> cursor : allocation.nodes().getDataNodes().values()) {
-                    Decision decision = allocation.deciders().shouldAutoExpandToNode(indexMetadata, cursor.value, allocation);
+                for (final DiscoveryNode cursor : allocation.nodes().getDataNodes().values()) {
+                    Decision decision = allocation.deciders().shouldAutoExpandToNode(indexMetadata, cursor, allocation);
                     if (decision.type() != Decision.Type.NO) {
                         numMatchingDataNodes++;
                     }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ClusterNameExpressionResolver.java b/server/src/main/java/org/opensearch/cluster/metadata/ClusterNameExpressionResolver.java
index 72f6f142ed290..fdc6c17cb3b13 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ClusterNameExpressionResolver.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ClusterNameExpressionResolver.java
@@ -43,6 +43,8 @@
 /**
  * Resolves cluster names from an expression. The expression must be the exact match of a cluster
  * name or must be a wildcard expression.
+ *
+ * @opensearch.internal
  */
 public final class ClusterNameExpressionResolver {
 
@@ -66,6 +68,11 @@ public List<String> resolveClusterNames(Set<String> remoteClusters, String clust
         }
     }
 
+    /**
+     * A wildcard expression resolver.
+     *
+     * @opensearch.internal
+     */
     private static class WildcardExpressionResolver {
 
         private List<String> resolve(Set<String> remoteClusters, String clusterExpression) {
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplate.java b/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplate.java
index c3ba1a2f7a45b..cab1b75afe3e1 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplate.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplate.java
@@ -35,14 +35,15 @@
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
@@ -53,6 +54,8 @@
  * component template is expected to be valid on its own. For example, if a component template
  * contains a field "foo", it's expected to contain all the necessary settings/mappings/etc for the
  * "foo" field. These component templates make up the individual pieces composing an index template.
+ *
+ * @opensearch.internal
  */
 public class ComponentTemplate extends AbstractDiffable<ComponentTemplate> implements ToXContentObject {
     private static final ParseField TEMPLATE = new ParseField("template");
@@ -149,7 +152,7 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplateMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplateMetadata.java
index 0d2496b5812be..8c755201fb4b7 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplateMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ComponentTemplateMetadata.java
@@ -37,13 +37,14 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.NamedDiff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.EnumSet;
@@ -54,6 +55,8 @@
 /**
  * {@link ComponentTemplateMetadata} is a custom {@link Metadata} implementation for storing a map
  * of component templates and their names.
+ *
+ * @opensearch.internal
  */
 public class ComponentTemplateMetadata implements Metadata.Custom {
     public static final String TYPE = "component_template";
@@ -151,9 +154,14 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * A diff between component template metadata.
+     *
+     * @opensearch.internal
+     */
     static class ComponentTemplateMetadataDiff implements NamedDiff<Metadata.Custom> {
 
         final Diff<Map<String, ComponentTemplate>> componentTemplateDiff;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplate.java b/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplate.java
index b9d71adc89c1c..2414521c3a438 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplate.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplate.java
@@ -38,15 +38,16 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.metadata.DataStream.TimestampField;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.DataStreamFieldMapper;
 import org.opensearch.index.mapper.MapperService;
 
@@ -58,12 +59,13 @@
 
 import static java.util.Collections.singletonMap;
 import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.common.collect.Map.of;
 
 /**
  * An index template is comprised of a set of index patterns, an optional template, and a list of
  * ids corresponding to component templates that should be composed in order when creating a new
  * index.
+ *
+ * @opensearch.internal
  */
 public class ComposableIndexTemplate extends AbstractDiffable<ComposableIndexTemplate> implements ToXContentObject {
     private static final ParseField INDEX_PATTERNS = new ParseField("index_patterns");
@@ -284,9 +286,14 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * Template for data stream.
+     *
+     * @opensearch.internal
+     */
     public static class DataStreamTemplate implements Writeable, ToXContentObject {
 
         private static final ParseField TIMESTAMP_FIELD_FIELD = new ParseField("timestamp_field");
@@ -329,7 +336,10 @@ public TimestampField getTimestampField() {
         public Map<String, Object> getDataStreamMappingSnippet() {
             return singletonMap(
                 MapperService.SINGLE_MAPPING_NAME,
-                singletonMap("_data_stream_timestamp", unmodifiableMap(of("enabled", true, "timestamp_field", getTimestampField().toMap())))
+                singletonMap(
+                    "_data_stream_timestamp",
+                    unmodifiableMap(Map.of("enabled", true, "timestamp_field", getTimestampField().toMap()))
+                )
             );
         }
 
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadata.java
index 46712a3b529b2..7056abcad8be6 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadata.java
@@ -37,13 +37,14 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.NamedDiff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.EnumSet;
@@ -54,6 +55,8 @@
 /**
  * The {@link ComposableIndexTemplateMetadata} class is a custom {@link Metadata.Custom} implementation that
  * stores a map of ids to {@link ComposableIndexTemplate} templates.
+ *
+ * @opensearch.internal
  */
 public class ComposableIndexTemplateMetadata implements Metadata.Custom {
     public static final String TYPE = "index_template";
@@ -152,9 +155,14 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * A diff between composable metadata templates.
+     *
+     * @opensearch.internal
+     */
     static class ComposableIndexTemplateMetadataDiff implements NamedDiff<Metadata.Custom> {
 
         final Diff<Map<String, ComposableIndexTemplate>> indexTemplateDiff;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/CryptoMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/CryptoMetadata.java
new file mode 100644
index 0000000000000..27803cb106005
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/metadata/CryptoMetadata.java
@@ -0,0 +1,167 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.admin.cluster.crypto.CryptoSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Metadata about encryption and decryption
+ *
+ * @opensearch.internal
+ */
+public class CryptoMetadata implements Writeable {
+    static final public String CRYPTO_METADATA_KEY = "crypto_metadata";
+    static final public String KEY_PROVIDER_NAME_KEY = "key_provider_name";
+    static final public String KEY_PROVIDER_TYPE_KEY = "key_provider_type";
+    static final public String SETTINGS_KEY = "settings";
+    private final String keyProviderName;
+    private final String keyProviderType;
+    private final Settings settings;
+
+    /**
+     * Constructs new crypto metadata
+     *
+     * @param keyProviderName     key provider name
+     * @param keyProviderType     key provider type
+     * @param settings crypto settings
+     */
+    public CryptoMetadata(String keyProviderName, String keyProviderType, Settings settings) {
+        this.keyProviderName = keyProviderName;
+        this.keyProviderType = keyProviderType;
+        this.settings = settings;
+    }
+
+    /**
+     * Returns key provider name
+     *
+     * @return Key provider name
+     */
+    public String keyProviderName() {
+        return this.keyProviderName;
+    }
+
+    /**
+     * Returns key provider type
+     *
+     * @return key provider type
+     */
+    public String keyProviderType() {
+        return this.keyProviderType;
+    }
+
+    /**
+     * Returns crypto settings
+     *
+     * @return crypto settings
+     */
+    public Settings settings() {
+        return this.settings;
+    }
+
+    public CryptoMetadata(StreamInput in) throws IOException {
+        keyProviderName = in.readString();
+        keyProviderType = in.readString();
+        settings = Settings.readSettingsFromStream(in);
+    }
+
+    public static CryptoMetadata fromRequest(CryptoSettings cryptoSettings) {
+        if (cryptoSettings == null) {
+            return null;
+        }
+        return new CryptoMetadata(cryptoSettings.getKeyProviderName(), cryptoSettings.getKeyProviderType(), cryptoSettings.getSettings());
+    }
+
+    /**
+     * Writes crypto metadata to stream output
+     *
+     * @param out stream output
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(keyProviderName);
+        out.writeString(keyProviderType);
+        Settings.writeSettingsToStream(settings, out);
+    }
+
+    public static CryptoMetadata fromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token;
+        String keyProviderType = null;
+        Settings settings = null;
+        String keyProviderName = parser.currentName();
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                String currentFieldName = parser.currentName();
+                if (KEY_PROVIDER_NAME_KEY.equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                        throw new OpenSearchParseException("failed to parse crypto metadata [{}], unknown type");
+                    }
+                    keyProviderName = parser.text();
+                } else if (KEY_PROVIDER_TYPE_KEY.equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                        throw new OpenSearchParseException("failed to parse crypto metadata [{}], unknown type");
+                    }
+                    keyProviderType = parser.text();
+                } else if (SETTINGS_KEY.equals(currentFieldName)) {
+                    if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                        throw new OpenSearchParseException("failed to parse crypto metadata [{}], unknown type");
+                    }
+                    settings = Settings.fromXContent(parser);
+                } else {
+                    throw new OpenSearchParseException("failed to parse crypto metadata, unknown field [{}]", currentFieldName);
+                }
+            } else {
+                throw new OpenSearchParseException("failed to parse repositories");
+            }
+        }
+        return new CryptoMetadata(keyProviderName, keyProviderType, settings);
+    }
+
+    public void toXContent(CryptoMetadata cryptoMetadata, XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject(CRYPTO_METADATA_KEY);
+        builder.field(KEY_PROVIDER_NAME_KEY, cryptoMetadata.keyProviderName());
+        builder.field(KEY_PROVIDER_TYPE_KEY, cryptoMetadata.keyProviderType());
+        builder.startObject(SETTINGS_KEY);
+        cryptoMetadata.settings().toXContent(builder, params);
+        builder.endObject();
+        builder.endObject();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        CryptoMetadata that = (CryptoMetadata) o;
+
+        if (!keyProviderName.equals(that.keyProviderName)) return false;
+        if (!keyProviderType.equals(that.keyProviderType)) return false;
+        return settings.equals(that.settings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(keyProviderName, keyProviderType, settings);
+    }
+
+    @Override
+    public String toString() {
+        return "CryptoMetadata{" + keyProviderName + "}{" + keyProviderType + "}{" + settings + "}";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/DataStream.java b/server/src/main/java/org/opensearch/cluster/metadata/DataStream.java
index eaf1b35ca2ce3..753f872f88b22 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/DataStream.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/DataStream.java
@@ -31,29 +31,57 @@
 
 package org.opensearch.cluster.metadata;
 
+import org.apache.lucene.document.LongPoint;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.PointValues;
+import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Primary DataStream class
+ *
+ * @opensearch.internal
+ */
 public final class DataStream extends AbstractDiffable<DataStream> implements ToXContentObject {
 
     public static final String BACKING_INDEX_PREFIX = ".ds-";
+    public static final String TIMESERIES_FIELDNAME = "@timestamp";
+    public static final Comparator<LeafReader> TIMESERIES_LEAF_SORTER = Comparator.comparingLong((LeafReader r) -> {
+        try {
+            PointValues points = r.getPointValues(TIMESERIES_FIELDNAME);
+            if (points != null) {
+                // could be a multipoint (probably not) but get the maximum time value anyway
+                byte[] sortValue = points.getMaxPackedValue();
+                // decode the first dimension because this should not be a multi dimension field
+                // it's a bug in the date field if it is
+                return LongPoint.decodeDimension(sortValue, 0);
+            } else {
+                // segment does not have a timestamp field, just return the minimum value
+                return Long.MIN_VALUE;
+            }
+        } catch (IOException e) {
+            throw new OpenSearchException("Not a timeseries Index! Field [{}] not found!", TIMESERIES_FIELDNAME);
+        }
+    }).reversed();
 
     private final String name;
     private final TimestampField timeStampField;
@@ -227,6 +255,11 @@ public int hashCode() {
         return Objects.hash(name, timeStampField, indices, generation);
     }
 
+    /**
+     * A timestamp field.
+     *
+     * @opensearch.internal
+     */
     public static final class TimestampField implements Writeable, ToXContentObject {
 
         static ParseField NAME_FIELD = new ParseField("name");
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/DataStreamMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/DataStreamMetadata.java
index d94b6f0c8cffc..ef880754ff429 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/DataStreamMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/DataStreamMetadata.java
@@ -37,13 +37,14 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.NamedDiff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.EnumSet;
@@ -53,6 +54,8 @@
 
 /**
  * Custom {@link Metadata} implementation for storing a map of {@link DataStream}s and their names.
+ *
+ * @opensearch.internal
  */
 public class DataStreamMetadata implements Metadata.Custom {
 
@@ -156,9 +159,14 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
+    /**
+     * Builder of data stream metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final Map<String, DataStream> dataStreams = new HashMap<>();
@@ -173,6 +181,11 @@ public DataStreamMetadata build() {
         }
     }
 
+    /**
+     * A diff between data stream metadata.
+     *
+     * @opensearch.internal
+     */
     static class DataStreamMetadataDiff implements NamedDiff<Metadata.Custom> {
 
         final Diff<Map<String, DataStream>> dataStreamDiff;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/DiffableStringMap.java b/server/src/main/java/org/opensearch/cluster/metadata/DiffableStringMap.java
index 2c35fbf4ae67e..8209c7bb56ad8 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/DiffableStringMap.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/DiffableStringMap.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.Diffable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.AbstractMap;
@@ -49,6 +49,8 @@
 /**
  * This is a {@code Map<String, String>} that implements AbstractDiffable so it
  * can be used for cluster state purposes
+ *
+ * @opensearch.internal
  */
 public class DiffableStringMap extends AbstractMap<String, String> implements Diffable<DiffableStringMap> {
 
@@ -88,6 +90,8 @@ public static Diff<DiffableStringMap> readDiffFrom(StreamInput in) throws IOExce
 
     /**
      * Represents differences between two DiffableStringMaps.
+     *
+     * @opensearch.internal
      */
     public static class DiffableStringMapDiff implements Diff<DiffableStringMap> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
index 653755664cbc0..0c316373e484f 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.common.Strings;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -46,12 +46,13 @@
 
 import static org.opensearch.cluster.metadata.DataStream.getDefaultBackingIndexName;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_HIDDEN_SETTING;
-import static org.opensearch.common.collect.List.copyOf;
 
 /**
  * An index abstraction is a reference to one or more concrete indices.
  * An index abstraction has a unique name and encapsulates all the  {@link IndexMetadata} instances it is pointing to.
  * Also depending on type it may refer to a single or many concrete indices and may or may not have a write index.
+ *
+ * @opensearch.internal
  */
 public interface IndexAbstraction {
 
@@ -137,6 +138,8 @@ public String getDisplayName() {
 
     /**
      * Represents an concrete index and encapsulates its {@link IndexMetadata}
+     *
+     * @opensearch.internal
      */
     class Index implements IndexAbstraction {
 
@@ -190,6 +193,8 @@ public boolean isSystem() {
 
     /**
      * Represents an alias and groups all {@link IndexMetadata} instances sharing the same alias name together.
+     *
+     * @opensearch.internal
      */
     class Alias implements IndexAbstraction {
 
@@ -327,6 +332,11 @@ private boolean isNonEmpty(List<IndexMetadata> idxMetas) {
         }
     }
 
+    /**
+     * A data stream.
+     *
+     * @opensearch.internal
+     */
     class DataStream implements IndexAbstraction {
 
         private final org.opensearch.cluster.metadata.DataStream dataStream;
@@ -335,7 +345,7 @@ class DataStream implements IndexAbstraction {
 
         public DataStream(org.opensearch.cluster.metadata.DataStream dataStream, List<IndexMetadata> dataStreamIndices) {
             this.dataStream = dataStream;
-            this.dataStreamIndices = copyOf(dataStreamIndices);
+            this.dataStreamIndices = List.copyOf(dataStreamIndices);
             this.writeIndex = dataStreamIndices.get(dataStreamIndices.size() - 1);
             assert writeIndex.getIndex().getName().equals(getDefaultBackingIndexName(dataStream.getName(), dataStream.getGeneration()));
         }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstractionResolver.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstractionResolver.java
index 4045ea938e373..a83c778a4b83a 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstractionResolver.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstractionResolver.java
@@ -43,6 +43,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Utility class to resolve index abstractions
+ *
+ * @opensearch.internal
+ */
 public class IndexAbstractionResolver {
 
     private final IndexNameExpressionResolver indexNameExpressionResolver;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexGraveyard.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexGraveyard.java
index c0b207158c9bc..0da948dc78c5d 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexGraveyard.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexGraveyard.java
@@ -35,19 +35,19 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.NamedDiff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -67,6 +67,8 @@
  * nodes and a node could be removed from the cluster for a period of time, the
  * tombstones remain in the cluster state for a fixed period of time, after which
  * they are purged.
+ *
+ * @opensearch.internal
  */
 public final class IndexGraveyard implements Metadata.Custom {
 
@@ -188,6 +190,8 @@ public static IndexGraveyard.Builder builder(final IndexGraveyard graveyard) {
 
     /**
      * A class to build an IndexGraveyard.
+     *
+     * @opensearch.internal
      */
     public static final class Builder {
         private List<Tombstone> tombstones;
@@ -273,6 +277,8 @@ public IndexGraveyard build(final Settings settings) {
 
     /**
      * A class representing a diff of two IndexGraveyard objects.
+     *
+     * @opensearch.internal
      */
     public static final class IndexGraveyardDiff implements NamedDiff<Metadata.Custom> {
 
@@ -360,6 +366,8 @@ public String getWriteableName() {
 
     /**
      * An individual tombstone entry for representing a deleted index.
+     *
+     * @opensearch.internal
      */
     public static final class Tombstone implements ToXContentObject, Writeable {
 
@@ -458,6 +466,8 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         /**
          * A builder for building tombstone entries.
+         *
+         * @opensearch.internal
          */
         private static final class Builder {
             private Index index;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
index 6510c57060fe0..b2c776df130b6 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java
@@ -32,11 +32,6 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.LongArrayList;
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-import org.opensearch.Assertions;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.action.admin.indices.rollover.RolloverInfo;
@@ -49,33 +44,35 @@
 import org.opensearch.cluster.node.DiscoveryNodeFilters;
 import org.opensearch.cluster.routing.allocation.IndexMetadataUpdater;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.index.Index;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.indices.replication.common.ReplicationType;
 
 import java.io.IOException;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.EnumSet;
@@ -85,6 +82,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.function.Function;
 
@@ -95,6 +93,11 @@
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
 
+/**
+ * Index metadata information
+ *
+ * @opensearch.internal
+ */
 public class IndexMetadata implements Diffable<IndexMetadata>, ToXContentFragment {
 
     public static final ClusterBlock INDEX_READ_ONLY_BLOCK = new ClusterBlock(
@@ -143,6 +146,21 @@ public class IndexMetadata implements Diffable<IndexMetadata>, ToXContentFragmen
         EnumSet.of(ClusterBlockLevel.METADATA_WRITE, ClusterBlockLevel.WRITE)
     );
 
+    public static final ClusterBlock REMOTE_READ_ONLY_ALLOW_DELETE = new ClusterBlock(
+        13,
+        "remote index is read-only",
+        false,
+        false,
+        true,
+        RestStatus.FORBIDDEN,
+        EnumSet.of(ClusterBlockLevel.METADATA_WRITE, ClusterBlockLevel.WRITE)
+    );
+
+    /**
+     * The state of the index.
+     *
+     * @opensearch.internal
+     */
     public enum State {
         OPEN((byte) 0),
         CLOSE((byte) 1);
@@ -260,9 +278,180 @@ public Iterator<Setting<?>> settings() {
         Property.IndexScope
     );
 
+    /**
+     * Used to specify the replication type for the index. By default, document replication is used.
+     */
+    public static final String SETTING_REPLICATION_TYPE = "index.replication.type";
+    public static final Setting<ReplicationType> INDEX_REPLICATION_TYPE_SETTING = new Setting<>(
+        SETTING_REPLICATION_TYPE,
+        ReplicationType.DOCUMENT.toString(),
+        ReplicationType::parseString,
+        new Setting.Validator<>() {
+
+            @Override
+            public void validate(final ReplicationType value) {}
+
+            @Override
+            public void validate(final ReplicationType value, final Map<Setting<?>, Object> settings) {
+                final Object remoteStoreEnabled = settings.get(INDEX_REMOTE_STORE_ENABLED_SETTING);
+                if (ReplicationType.SEGMENT.equals(value) == false && Objects.equals(remoteStoreEnabled, true)) {
+                    throw new IllegalArgumentException(
+                        "To enable "
+                            + INDEX_REMOTE_STORE_ENABLED_SETTING.getKey()
+                            + ", "
+                            + INDEX_REPLICATION_TYPE_SETTING.getKey()
+                            + " should be set to "
+                            + ReplicationType.SEGMENT
+                    );
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                final List<Setting<?>> settings = List.of(INDEX_REMOTE_STORE_ENABLED_SETTING);
+                return settings.iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.Final
+    );
+
+    public static final String SETTING_REMOTE_STORE_ENABLED = "index.remote_store.enabled";
+
+    public static final String SETTING_REMOTE_SEGMENT_STORE_REPOSITORY = "index.remote_store.segment.repository";
+
+    public static final String SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY = "index.remote_store.translog.repository";
+
+    /**
+     * Used to specify if the index data should be persisted in the remote store.
+     */
+    public static final Setting<Boolean> INDEX_REMOTE_STORE_ENABLED_SETTING = Setting.boolSetting(
+        SETTING_REMOTE_STORE_ENABLED,
+        false,
+        new Setting.Validator<>() {
+
+            @Override
+            public void validate(final Boolean value) {}
+
+            @Override
+            public void validate(final Boolean value, final Map<Setting<?>, Object> settings) {
+                final Object replicationType = settings.get(INDEX_REPLICATION_TYPE_SETTING);
+                if (ReplicationType.SEGMENT.equals(replicationType) == false && value) {
+                    throw new IllegalArgumentException(
+                        "To enable "
+                            + INDEX_REMOTE_STORE_ENABLED_SETTING.getKey()
+                            + ", "
+                            + INDEX_REPLICATION_TYPE_SETTING.getKey()
+                            + " should be set to "
+                            + ReplicationType.SEGMENT
+                    );
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                final List<Setting<?>> settings = List.of(INDEX_REPLICATION_TYPE_SETTING);
+                return settings.iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.PrivateIndex,
+        Property.Dynamic
+    );
+
+    /**
+     * Used to specify remote store repository to use for this index.
+     */
+    public static final Setting<String> INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING = Setting.simpleString(
+        SETTING_REMOTE_SEGMENT_STORE_REPOSITORY,
+        new Setting.Validator<>() {
+
+            @Override
+            public void validate(final String value) {}
+
+            @Override
+            public void validate(final String value, final Map<Setting<?>, Object> settings) {
+                if (value == null || value.isEmpty()) {
+                    throw new IllegalArgumentException(
+                        "Setting "
+                            + INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING.getKey()
+                            + " should be provided with non-empty repository ID"
+                    );
+                } else {
+                    validateRemoteStoreSettingEnabled(settings, INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING);
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                final List<Setting<?>> settings = Collections.singletonList(INDEX_REMOTE_STORE_ENABLED_SETTING);
+                return settings.iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.PrivateIndex,
+        Property.Dynamic
+    );
+
+    private static void validateRemoteStoreSettingEnabled(final Map<Setting<?>, Object> settings, Setting<?> setting) {
+        final Boolean isRemoteSegmentStoreEnabled = (Boolean) settings.get(INDEX_REMOTE_STORE_ENABLED_SETTING);
+        if (isRemoteSegmentStoreEnabled == false) {
+            throw new IllegalArgumentException(
+                "Settings "
+                    + setting.getKey()
+                    + " can only be set/enabled when "
+                    + INDEX_REMOTE_STORE_ENABLED_SETTING.getKey()
+                    + " is set to true"
+            );
+        }
+    }
+
+    public static final Setting<String> INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING = Setting.simpleString(
+        SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY,
+        new Setting.Validator<>() {
+
+            @Override
+            public void validate(final String value) {}
+
+            @Override
+            public void validate(final String value, final Map<Setting<?>, Object> settings) {
+                if (value == null || value.isEmpty()) {
+                    throw new IllegalArgumentException(
+                        "Setting " + INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING.getKey() + " should be provided with non-empty repository ID"
+                    );
+                } else {
+                    final Boolean isRemoteTranslogStoreEnabled = (Boolean) settings.get(INDEX_REMOTE_STORE_ENABLED_SETTING);
+                    if (isRemoteTranslogStoreEnabled == null || isRemoteTranslogStoreEnabled == false) {
+                        throw new IllegalArgumentException(
+                            "Settings "
+                                + INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING.getKey()
+                                + " can only be set/enabled when "
+                                + INDEX_REMOTE_STORE_ENABLED_SETTING.getKey()
+                                + " is set to true"
+                        );
+                    }
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                final List<Setting<?>> settings = Collections.singletonList(INDEX_REMOTE_STORE_ENABLED_SETTING);
+                return settings.iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.PrivateIndex,
+        Property.Dynamic
+    );
+
     public static final String SETTING_AUTO_EXPAND_REPLICAS = "index.auto_expand_replicas";
     public static final Setting<AutoExpandReplicas> INDEX_AUTO_EXPAND_REPLICAS_SETTING = AutoExpandReplicas.SETTING;
 
+    /**
+     * Blocks the API.
+     *
+     * @opensearch.internal
+     */
     public enum APIBlock implements Writeable {
         READ_ONLY("read_only", INDEX_READ_ONLY_BLOCK),
         READ("read", INDEX_READ_BLOCK),
@@ -373,7 +562,7 @@ public static APIBlock readFrom(StreamInput input) throws IOException {
         Function.identity(),
         Property.IndexScope
     );
-    public static final String INDEX_UUID_NA_VALUE = "_na_";
+    public static final String INDEX_UUID_NA_VALUE = Strings.UNKNOWN_UUID_VALUE;
 
     public static final String INDEX_ROUTING_REQUIRE_GROUP_PREFIX = "index.routing.allocation.require";
     public static final String INDEX_ROUTING_INCLUDE_GROUP_PREFIX = "index.routing.allocation.include";
@@ -467,15 +656,15 @@ public static APIBlock readFrom(StreamInput input) throws IOException {
 
     private final State state;
 
-    private final ImmutableOpenMap<String, AliasMetadata> aliases;
+    private final Map<String, AliasMetadata> aliases;
 
     private final Settings settings;
 
-    private final ImmutableOpenMap<String, MappingMetadata> mappings;
+    private final Map<String, MappingMetadata> mappings;
 
-    private final ImmutableOpenMap<String, DiffableStringMap> customData;
+    private final Map<String, DiffableStringMap> customData;
 
-    private final ImmutableOpenIntMap<Set<String>> inSyncAllocationIds;
+    private final Map<Integer, Set<String>> inSyncAllocationIds;
 
     private final transient int totalNumberOfShards;
 
@@ -488,7 +677,7 @@ public static APIBlock readFrom(StreamInput input) throws IOException {
     private final Version indexUpgradedVersion;
 
     private final ActiveShardCount waitForActiveShards;
-    private final ImmutableOpenMap<String, RolloverInfo> rolloverInfos;
+    private final Map<String, RolloverInfo> rolloverInfos;
     private final boolean isSystem;
 
     private IndexMetadata(
@@ -502,10 +691,10 @@ private IndexMetadata(
         final int numberOfShards,
         final int numberOfReplicas,
         final Settings settings,
-        final ImmutableOpenMap<String, MappingMetadata> mappings,
-        final ImmutableOpenMap<String, AliasMetadata> aliases,
-        final ImmutableOpenMap<String, DiffableStringMap> customData,
-        final ImmutableOpenIntMap<Set<String>> inSyncAllocationIds,
+        final Map<String, MappingMetadata> mappings,
+        final Map<String, AliasMetadata> aliases,
+        final Map<String, DiffableStringMap> customData,
+        final Map<Integer, Set<String>> inSyncAllocationIds,
         final DiscoveryNodeFilters requireFilters,
         final DiscoveryNodeFilters initialRecoveryFilters,
         final DiscoveryNodeFilters includeFilters,
@@ -515,7 +704,7 @@ private IndexMetadata(
         final int routingNumShards,
         final int routingPartitionSize,
         final ActiveShardCount waitForActiveShards,
-        final ImmutableOpenMap<String, RolloverInfo> rolloverInfos,
+        final Map<String, RolloverInfo> rolloverInfos,
         final boolean isSystem
     ) {
 
@@ -534,10 +723,10 @@ private IndexMetadata(
         this.numberOfReplicas = numberOfReplicas;
         this.totalNumberOfShards = numberOfShards * (numberOfReplicas + 1);
         this.settings = settings;
-        this.mappings = mappings;
-        this.customData = customData;
-        this.aliases = aliases;
-        this.inSyncAllocationIds = inSyncAllocationIds;
+        this.mappings = Collections.unmodifiableMap(mappings);
+        this.customData = Collections.unmodifiableMap(customData);
+        this.aliases = Collections.unmodifiableMap(aliases);
+        this.inSyncAllocationIds = Collections.unmodifiableMap(inSyncAllocationIds);
         this.requireFilters = requireFilters;
         this.includeFilters = includeFilters;
         this.excludeFilters = excludeFilters;
@@ -548,7 +737,7 @@ private IndexMetadata(
         this.routingFactor = routingNumShards / numberOfShards;
         this.routingPartitionSize = routingPartitionSize;
         this.waitForActiveShards = waitForActiveShards;
-        this.rolloverInfos = rolloverInfos;
+        this.rolloverInfos = Collections.unmodifiableMap(rolloverInfos);
         this.isSystem = isSystem;
         assert numberOfShards * routingFactor == routingNumShards : routingNumShards + " must be a multiple of " + numberOfShards;
     }
@@ -656,7 +845,7 @@ public Settings getSettings() {
         return settings;
     }
 
-    public ImmutableOpenMap<String, AliasMetadata> getAliases() {
+    public Map<String, AliasMetadata> getAliases() {
         return this.aliases;
     }
 
@@ -665,8 +854,8 @@ public ImmutableOpenMap<String, AliasMetadata> getAliases() {
      */
     @Nullable
     public MappingMetadata mapping() {
-        for (ObjectObjectCursor<String, MappingMetadata> cursor : mappings) {
-            return cursor.value;
+        for (final MappingMetadata cursor : mappings.values()) {
+            return cursor;
         }
         return null;
     }
@@ -682,7 +871,7 @@ public Index getResizeSourceIndex() {
             : null;
     }
 
-    ImmutableOpenMap<String, DiffableStringMap> getCustomData() {
+    Map<String, DiffableStringMap> getCustomData() {
         return this.customData;
     }
 
@@ -690,11 +879,11 @@ public Map<String, String> getCustomData(final String key) {
         return this.customData.get(key);
     }
 
-    public ImmutableOpenIntMap<Set<String>> getInSyncAllocationIds() {
+    public Map<Integer, Set<String>> getInSyncAllocationIds() {
         return inSyncAllocationIds;
     }
 
-    public ImmutableOpenMap<String, RolloverInfo> getRolloverInfos() {
+    public Map<String, RolloverInfo> getRolloverInfos() {
         return rolloverInfos;
     }
 
@@ -814,6 +1003,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * A diff of index metadata.
+     *
+     * @opensearch.internal
+     */
     private static class IndexMetadataDiff implements Diff<IndexMetadata> {
 
         private final String index;
@@ -825,11 +1019,11 @@ private static class IndexMetadataDiff implements Diff<IndexMetadata> {
         private final long[] primaryTerms;
         private final State state;
         private final Settings settings;
-        private final Diff<ImmutableOpenMap<String, MappingMetadata>> mappings;
-        private final Diff<ImmutableOpenMap<String, AliasMetadata>> aliases;
-        private final Diff<ImmutableOpenMap<String, DiffableStringMap>> customData;
-        private final Diff<ImmutableOpenIntMap<Set<String>>> inSyncAllocationIds;
-        private final Diff<ImmutableOpenMap<String, RolloverInfo>> rolloverInfos;
+        private final Diff<Map<String, MappingMetadata>> mappings;
+        private final Diff<Map<String, AliasMetadata>> aliases;
+        private final Diff<Map<String, DiffableStringMap>> customData;
+        private final Diff<Map<Integer, Set<String>>> inSyncAllocationIds;
+        private final Diff<Map<String, RolloverInfo>> rolloverInfos;
         private final boolean isSystem;
 
         IndexMetadataDiff(IndexMetadata before, IndexMetadata after) {
@@ -878,19 +1072,15 @@ private static class IndexMetadataDiff implements Diff<IndexMetadata> {
             state = State.fromId(in.readByte());
             settings = Settings.readSettingsFromStream(in);
             primaryTerms = in.readVLongArray();
-            mappings = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), MAPPING_DIFF_VALUE_READER);
-            aliases = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), ALIAS_METADATA_DIFF_VALUE_READER);
-            customData = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_DIFF_VALUE_READER);
-            inSyncAllocationIds = DiffableUtils.readImmutableOpenIntMapDiff(
+            mappings = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), MAPPING_DIFF_VALUE_READER);
+            aliases = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), ALIAS_METADATA_DIFF_VALUE_READER);
+            customData = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_DIFF_VALUE_READER);
+            inSyncAllocationIds = DiffableUtils.readJdkMapDiff(
                 in,
                 DiffableUtils.getVIntKeySerializer(),
                 DiffableUtils.StringSetValueSerializer.getInstance()
             );
-            rolloverInfos = DiffableUtils.readImmutableOpenMapDiff(
-                in,
-                DiffableUtils.getStringKeySerializer(),
-                ROLLOVER_INFO_DIFF_VALUE_READER
-            );
+            rolloverInfos = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), ROLLOVER_INFO_DIFF_VALUE_READER);
             if (in.getVersion().onOrAfter(SYSTEM_INDEX_FLAG_ADDED)) {
                 isSystem = in.readBoolean();
             } else {
@@ -1002,26 +1192,26 @@ public void writeTo(StreamOutput out) throws IOException {
         writeSettingsToStream(settings, out);
         out.writeVLongArray(primaryTerms);
         out.writeVInt(mappings.size());
-        for (ObjectCursor<MappingMetadata> cursor : mappings.values()) {
-            cursor.value.writeTo(out);
+        for (final MappingMetadata cursor : mappings.values()) {
+            cursor.writeTo(out);
         }
         out.writeVInt(aliases.size());
-        for (ObjectCursor<AliasMetadata> cursor : aliases.values()) {
-            cursor.value.writeTo(out);
+        for (final AliasMetadata cursor : aliases.values()) {
+            cursor.writeTo(out);
         }
         out.writeVInt(customData.size());
-        for (final ObjectObjectCursor<String, DiffableStringMap> cursor : customData) {
-            out.writeString(cursor.key);
-            cursor.value.writeTo(out);
+        for (final Map.Entry<String, DiffableStringMap> cursor : customData.entrySet()) {
+            out.writeString(cursor.getKey());
+            cursor.getValue().writeTo(out);
         }
         out.writeVInt(inSyncAllocationIds.size());
-        for (IntObjectCursor<Set<String>> cursor : inSyncAllocationIds) {
-            out.writeVInt(cursor.key);
-            DiffableUtils.StringSetValueSerializer.getInstance().write(cursor.value, out);
+        for (final Map.Entry<Integer, Set<String>> cursor : inSyncAllocationIds.entrySet()) {
+            out.writeVInt(cursor.getKey());
+            DiffableUtils.StringSetValueSerializer.getInstance().write(cursor.getValue(), out);
         }
         out.writeVInt(rolloverInfos.size());
-        for (ObjectCursor<RolloverInfo> cursor : rolloverInfos.values()) {
-            cursor.value.writeTo(out);
+        for (final RolloverInfo cursor : rolloverInfos.values()) {
+            cursor.writeTo(out);
         }
         if (out.getVersion().onOrAfter(SYSTEM_INDEX_FLAG_ADDED)) {
             out.writeBoolean(isSystem);
@@ -1040,6 +1230,11 @@ public static Builder builder(IndexMetadata indexMetadata) {
         return new Builder(indexMetadata);
     }
 
+    /**
+     * Builder of index metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private String index;
@@ -1050,21 +1245,21 @@ public static class Builder {
         private long aliasesVersion = 1;
         private long[] primaryTerms = null;
         private Settings settings = Settings.Builder.EMPTY_SETTINGS;
-        private final ImmutableOpenMap.Builder<String, MappingMetadata> mappings;
-        private final ImmutableOpenMap.Builder<String, AliasMetadata> aliases;
-        private final ImmutableOpenMap.Builder<String, DiffableStringMap> customMetadata;
-        private final ImmutableOpenIntMap.Builder<Set<String>> inSyncAllocationIds;
-        private final ImmutableOpenMap.Builder<String, RolloverInfo> rolloverInfos;
+        private final Map<String, MappingMetadata> mappings;
+        private final Map<String, AliasMetadata> aliases;
+        private final Map<String, DiffableStringMap> customMetadata;
+        private final Map<Integer, Set<String>> inSyncAllocationIds;
+        private final Map<String, RolloverInfo> rolloverInfos;
         private Integer routingNumShards;
         private boolean isSystem;
 
         public Builder(String index) {
             this.index = index;
-            this.mappings = ImmutableOpenMap.builder();
-            this.aliases = ImmutableOpenMap.builder();
-            this.customMetadata = ImmutableOpenMap.builder();
-            this.inSyncAllocationIds = ImmutableOpenIntMap.builder();
-            this.rolloverInfos = ImmutableOpenMap.builder();
+            this.mappings = new HashMap<>();
+            this.aliases = new HashMap<>();
+            this.customMetadata = new HashMap<>();
+            this.inSyncAllocationIds = new HashMap<>();
+            this.rolloverInfos = new HashMap<>();
             this.isSystem = false;
         }
 
@@ -1077,12 +1272,12 @@ public Builder(IndexMetadata indexMetadata) {
             this.aliasesVersion = indexMetadata.aliasesVersion;
             this.settings = indexMetadata.getSettings();
             this.primaryTerms = indexMetadata.primaryTerms.clone();
-            this.mappings = ImmutableOpenMap.builder(indexMetadata.mappings);
-            this.aliases = ImmutableOpenMap.builder(indexMetadata.aliases);
-            this.customMetadata = ImmutableOpenMap.builder(indexMetadata.customData);
+            this.mappings = new HashMap<>(indexMetadata.mappings);
+            this.aliases = new HashMap<>(indexMetadata.aliases);
+            this.customMetadata = new HashMap<>(indexMetadata.customData);
             this.routingNumShards = indexMetadata.routingNumShards;
-            this.inSyncAllocationIds = ImmutableOpenIntMap.builder(indexMetadata.inSyncAllocationIds);
-            this.rolloverInfos = ImmutableOpenMap.builder(indexMetadata.rolloverInfos);
+            this.inSyncAllocationIds = new HashMap<>(indexMetadata.inSyncAllocationIds);
+            this.rolloverInfos = new HashMap<>(indexMetadata.rolloverInfos);
             this.isSystem = indexMetadata.isSystem;
         }
 
@@ -1157,7 +1352,7 @@ public Builder putMapping(String source) throws IOException {
             putMapping(
                 new MappingMetadata(
                     MapperService.SINGLE_MAPPING_NAME,
-                    XContentHelper.convertToMap(XContentFactory.xContent(source), source, true)
+                    XContentHelper.convertToMap(MediaTypeRegistry.xContent(source).xContent(), source, true)
                 )
             );
             return this;
@@ -1301,7 +1496,7 @@ public boolean isSystem() {
         }
 
         public IndexMetadata build() {
-            ImmutableOpenMap.Builder<String, AliasMetadata> tmpAliases = aliases;
+            final Map<String, AliasMetadata> tmpAliases = aliases;
             Settings tmpSettings = settings;
 
             /*
@@ -1333,7 +1528,7 @@ public IndexMetadata build() {
             }
 
             // fill missing slots in inSyncAllocationIds with empty set if needed and make all entries immutable
-            ImmutableOpenIntMap.Builder<Set<String>> filledInSyncAllocationIds = ImmutableOpenIntMap.builder();
+            final Map<Integer, Set<String>> filledInSyncAllocationIds = new HashMap<>();
             for (int i = 0; i < numberOfShards; i++) {
                 if (inSyncAllocationIds.containsKey(i)) {
                     filledInSyncAllocationIds.put(i, Collections.unmodifiableSet(new HashSet<>(inSyncAllocationIds.get(i))));
@@ -1369,7 +1564,7 @@ public IndexMetadata build() {
             } else {
                 initialRecoveryFilters = DiscoveryNodeFilters.buildOrUpdateFromKeyValue(null, OR, initialRecoveryMap);
             }
-            Version indexCreatedVersion = Version.indexCreated(settings);
+            Version indexCreatedVersion = indexCreated(settings);
             Version indexUpgradedVersion = settings.getAsVersion(IndexMetadata.SETTING_VERSION_UPGRADED, indexCreatedVersion);
 
             if (primaryTerms == null) {
@@ -1411,10 +1606,10 @@ public IndexMetadata build() {
                 numberOfShards,
                 numberOfReplicas,
                 tmpSettings,
-                mappings.build(),
-                tmpAliases.build(),
-                customMetadata.build(),
-                filledInSyncAllocationIds.build(),
+                mappings,
+                tmpAliases,
+                customMetadata,
+                filledInSyncAllocationIds,
                 requireFilters,
                 initialRecoveryFilters,
                 includeFilters,
@@ -1424,7 +1619,7 @@ public IndexMetadata build() {
                 getRoutingNumShards(),
                 routingPartitionSize,
                 waitForActiveShards,
-                rolloverInfos.build(),
+                rolloverInfos,
                 isSystem
             );
         }
@@ -1480,15 +1675,15 @@ public static void toXContent(IndexMetadata indexMetadata, XContentBuilder build
                 builder.endObject();
             }
 
-            for (ObjectObjectCursor<String, DiffableStringMap> cursor : indexMetadata.customData) {
-                builder.field(cursor.key);
-                builder.map(cursor.value);
+            for (final Map.Entry<String, DiffableStringMap> cursor : indexMetadata.customData.entrySet()) {
+                builder.field(cursor.getKey());
+                builder.map(cursor.getValue());
             }
 
             if (context != Metadata.XContentContext.API) {
                 builder.startObject(KEY_ALIASES);
-                for (ObjectCursor<AliasMetadata> cursor : indexMetadata.getAliases().values()) {
-                    AliasMetadata.Builder.toXContent(cursor.value, builder, params);
+                for (final AliasMetadata cursor : indexMetadata.getAliases().values()) {
+                    AliasMetadata.Builder.toXContent(cursor, builder, params);
                 }
                 builder.endObject();
 
@@ -1499,8 +1694,8 @@ public static void toXContent(IndexMetadata indexMetadata, XContentBuilder build
                 builder.endArray();
             } else {
                 builder.startArray(KEY_ALIASES);
-                for (ObjectCursor<String> cursor : indexMetadata.getAliases().keys()) {
-                    builder.value(cursor.value);
+                for (final String cursor : indexMetadata.getAliases().keySet()) {
+                    builder.value(cursor);
                 }
                 builder.endArray();
 
@@ -1512,9 +1707,9 @@ public static void toXContent(IndexMetadata indexMetadata, XContentBuilder build
             }
 
             builder.startObject(KEY_IN_SYNC_ALLOCATIONS);
-            for (IntObjectCursor<Set<String>> cursor : indexMetadata.inSyncAllocationIds) {
-                builder.startArray(String.valueOf(cursor.key));
-                for (String allocationId : cursor.value) {
+            for (final Map.Entry<Integer, Set<String>> cursor : indexMetadata.inSyncAllocationIds.entrySet()) {
+                builder.startArray(String.valueOf(cursor.getKey()));
+                for (String allocationId : cursor.getValue()) {
                     builder.value(allocationId);
                 }
                 builder.endArray();
@@ -1522,8 +1717,8 @@ public static void toXContent(IndexMetadata indexMetadata, XContentBuilder build
             builder.endObject();
 
             builder.startObject(KEY_ROLLOVER_INFOS);
-            for (ObjectCursor<RolloverInfo> cursor : indexMetadata.getRolloverInfos().values()) {
-                cursor.value.toXContent(builder, params);
+            for (final RolloverInfo cursor : indexMetadata.getRolloverInfos().values()) {
+                cursor.toXContent(builder, params);
             }
             builder.endObject();
             builder.field(KEY_SYSTEM, indexMetadata.isSystem);
@@ -1627,7 +1822,7 @@ public static IndexMetadata fromXContent(XContentParser parser) throws IOExcepti
                             }
                         }
                     } else if (KEY_PRIMARY_TERMS.equals(currentFieldName)) {
-                        LongArrayList list = new LongArrayList();
+                        final List<Long> list = new ArrayList<>();
                         while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
                             if (token == XContentParser.Token.VALUE_NUMBER) {
                                 list.add(parser.longValue());
@@ -1635,7 +1830,7 @@ public static IndexMetadata fromXContent(XContentParser parser) throws IOExcepti
                                 throw new IllegalStateException("found a non-numeric value under [" + KEY_PRIMARY_TERMS + "]");
                             }
                         }
-                        builder.primaryTerms(list.toArray());
+                        builder.primaryTerms(list.stream().mapToLong(i -> i).toArray());
                     } else {
                         throw new IllegalArgumentException("Unexpected field for an array " + currentFieldName);
                     }
@@ -1664,13 +1859,14 @@ public static IndexMetadata fromXContent(XContentParser parser) throws IOExcepti
                     throw new IllegalArgumentException("Unexpected token " + token);
                 }
             }
-            if (Assertions.ENABLED) {
+            // Reference:
+            // https://github.com/opensearch-project/OpenSearch/blob/4dde0f2a3b445b2fc61dab29c5a2178967f4a3e3/server/src/main/java/org/opensearch/cluster/metadata/IndexMetadata.java#L1620-L1628
+            Version legacyVersion = LegacyESVersion.fromId(6050099);
+            if (Assertions.ENABLED && indexCreated(builder.settings).onOrAfter(legacyVersion)) {
                 assert mappingVersion : "mapping version should be present for indices";
-            }
-            if (Assertions.ENABLED) {
                 assert settingsVersion : "settings version should be present for indices";
             }
-            if (Assertions.ENABLED && Version.indexCreated(builder.settings).onOrAfter(LegacyESVersion.V_7_2_0)) {
+            if (Assertions.ENABLED && indexCreated(builder.settings).onOrAfter(LegacyESVersion.V_7_2_0)) {
                 assert aliasesVersion : "aliases version should be present for indices created on or after 7.2.0";
             }
             return builder.build();
@@ -1707,10 +1903,29 @@ public static Settings addHumanReadableSettings(Settings settings) {
         FORMAT_PARAMS = new MapParams(params);
     }
 
+    /**
+     * Return the version the index was created from the provided index settings
+     *
+     * This looks for the presence of the {@link Version} object with key {@link IndexMetadata#SETTING_VERSION_CREATED}
+     */
+    public static Version indexCreated(final Settings indexSettings) {
+        final Version indexVersion = SETTING_INDEX_VERSION_CREATED.get(indexSettings);
+        if (indexVersion.equals(Version.V_EMPTY)) {
+            final String message = String.format(
+                Locale.ROOT,
+                "[%s] is not present in the index settings for index with UUID [%s]",
+                SETTING_INDEX_VERSION_CREATED.getKey(),
+                indexSettings.get(IndexMetadata.SETTING_INDEX_UUID)
+            );
+            throw new IllegalStateException(message);
+        }
+        return indexVersion;
+    }
+
     /**
      * State format for {@link IndexMetadata} to write to and load from disk
      */
-    public static final MetadataStateFormat<IndexMetadata> FORMAT = new MetadataStateFormat<IndexMetadata>(INDEX_STATE_FILE_PREFIX) {
+    public static final MetadataStateFormat<IndexMetadata> FORMAT = new MetadataStateFormat<>(INDEX_STATE_FILE_PREFIX) {
 
         @Override
         public void toXContent(XContentBuilder builder, IndexMetadata state) throws IOException {
@@ -1774,8 +1989,8 @@ public static ShardId selectCloneShard(int shardId, IndexMetadata sourceIndexMet
             throw new IllegalArgumentException(
                 "the number of target shards ("
                     + numTargetShards
-                    + ") must be the same as the number of "
-                    + " source shards ( "
+                    + ") must be the same as the number of"
+                    + " source shards ("
                     + numSourceShards
                     + ")"
             );
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexNameExpressionResolver.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexNameExpressionResolver.java
index bd8535d18c9cb..86961010c77d6 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexNameExpressionResolver.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexNameExpressionResolver.java
@@ -40,18 +40,18 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.time.DateUtils;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.indices.InvalidIndexNameException;
@@ -76,6 +76,12 @@
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
+/**
+ * Resolves index name from an expression
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class IndexNameExpressionResolver {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(IndexNameExpressionResolver.class);
 
@@ -85,10 +91,7 @@ public class IndexNameExpressionResolver {
 
     private final DateMathExpressionResolver dateMathExpressionResolver = new DateMathExpressionResolver();
     private final WildcardExpressionResolver wildcardExpressionResolver = new WildcardExpressionResolver();
-    private final List<ExpressionResolver> expressionResolvers = org.opensearch.common.collect.List.of(
-        dateMathExpressionResolver,
-        wildcardExpressionResolver
-    );
+    private final List<ExpressionResolver> expressionResolvers = List.of(dateMathExpressionResolver, wildcardExpressionResolver);
 
     private final ThreadContext threadContext;
 
@@ -172,7 +175,7 @@ public List<String> dataStreamNames(ClusterState state, IndicesOptions options,
         }
 
         List<String> dataStreams = wildcardExpressionResolver.resolve(context, Arrays.asList(indexExpressions));
-        return ((dataStreams == null) ? org.opensearch.common.collect.List.<String>of() : dataStreams).stream()
+        return ((dataStreams == null) ? List.<String>of() : dataStreams).stream()
             .map(x -> state.metadata().getIndicesLookup().get(x))
             .filter(Objects::nonNull)
             .filter(ia -> ia.getType() == IndexAbstraction.Type.DATA_STREAM)
@@ -567,12 +570,11 @@ public String[] indexAliases(
             return null;
         }
 
-        final ImmutableOpenMap<String, AliasMetadata> indexAliases = indexMetadata.getAliases();
+        final Map<String, AliasMetadata> indexAliases = indexMetadata.getAliases();
         final AliasMetadata[] aliasCandidates;
         if (iterateIndexAliases(indexAliases.size(), resolvedExpressions.size())) {
             // faster to iterate indexAliases
             aliasCandidates = StreamSupport.stream(Spliterators.spliteratorUnknownSize(indexAliases.values().iterator(), 0), false)
-                .map(cursor -> cursor.value)
                 .filter(aliasMetadata -> resolvedExpressions.contains(aliasMetadata.alias()))
                 .toArray(AliasMetadata[]::new);
         } else {
@@ -768,6 +770,11 @@ public boolean isSystemIndexAccessAllowed() {
         return Booleans.parseBoolean(threadContext.getHeader(SYSTEM_INDEX_ACCESS_CONTROL_HEADER_KEY), true);
     }
 
+    /**
+     * Context for the resolver.
+     *
+     * @opensearch.internal
+     */
     public static class Context {
 
         private final ClusterState state;
@@ -907,6 +914,8 @@ private interface ExpressionResolver {
 
     /**
      * Resolves alias/index name expressions with wildcards into the corresponding concrete indices/aliases
+     *
+     * @opensearch.internal
      */
     static final class WildcardExpressionResolver implements ExpressionResolver {
 
@@ -1187,6 +1196,11 @@ private static List<String> resolveEmptyOrTrivialWildcard(IndicesOptions options
         }
     }
 
+    /**
+     * A date math expression resolver.
+     *
+     * @opensearch.internal
+     */
     public static final class DateMathExpressionResolver implements ExpressionResolver {
 
         private static final DateFormatter DEFAULT_DATE_FORMATTER = DateFormatter.forPattern("uuuu.MM.dd");
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexTemplateMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexTemplateMetadata.java
index 810365589ae1f..272bb132197af 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexTemplateMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexTemplateMetadata.java
@@ -31,37 +31,42 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 
+/**
+ * Metadata for Index Templates
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class IndexTemplateMetadata extends AbstractDiffable<IndexTemplateMetadata> {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(IndexTemplateMetadata.class);
@@ -95,9 +100,9 @@ public class IndexTemplateMetadata extends AbstractDiffable<IndexTemplateMetadat
     private final Settings settings;
 
     // the mapping source should always include the type as top level
-    private final ImmutableOpenMap<String, CompressedXContent> mappings;
+    private final Map<String, CompressedXContent> mappings;
 
-    private final ImmutableOpenMap<String, AliasMetadata> aliases;
+    private final Map<String, AliasMetadata> aliases;
 
     public IndexTemplateMetadata(
         String name,
@@ -105,8 +110,8 @@ public IndexTemplateMetadata(
         Integer version,
         List<String> patterns,
         Settings settings,
-        ImmutableOpenMap<String, CompressedXContent> mappings,
-        ImmutableOpenMap<String, AliasMetadata> aliases
+        final Map<String, CompressedXContent> mappings,
+        final Map<String, AliasMetadata> aliases
     ) {
         if (patterns == null || patterns.isEmpty()) {
             throw new IllegalArgumentException("Index patterns must not be null or empty; got " + patterns);
@@ -116,7 +121,7 @@ public IndexTemplateMetadata(
         this.version = version;
         this.patterns = patterns;
         this.settings = settings;
-        this.mappings = mappings;
+        this.mappings = Collections.unmodifiableMap(mappings);
         if (this.mappings.size() > 1) {
             deprecationLogger.deprecate(
                 "index-templates",
@@ -124,7 +129,7 @@ public IndexTemplateMetadata(
                 name
             );
         }
-        this.aliases = aliases;
+        this.aliases = Collections.unmodifiableMap(aliases);
     }
 
     public String name() {
@@ -165,18 +170,18 @@ public CompressedXContent mappings() {
         if (this.mappings.isEmpty()) {
             return null;
         }
-        return this.mappings.iterator().next().value;
+        return this.mappings.values().iterator().next();
     }
 
     public CompressedXContent getMappings() {
         return this.mappings();
     }
 
-    public ImmutableOpenMap<String, AliasMetadata> aliases() {
+    public Map<String, AliasMetadata> aliases() {
         return this.aliases;
     }
 
-    public ImmutableOpenMap<String, AliasMetadata> getAliases() {
+    public Map<String, AliasMetadata> getAliases() {
         return this.aliases;
     }
 
@@ -241,13 +246,13 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeStringCollection(patterns);
         Settings.writeSettingsToStream(settings, out);
         out.writeVInt(mappings.size());
-        for (ObjectObjectCursor<String, CompressedXContent> cursor : mappings) {
-            out.writeString(cursor.key);
-            cursor.value.writeTo(out);
+        for (final Map.Entry<String, CompressedXContent> cursor : mappings.entrySet()) {
+            out.writeString(cursor.getKey());
+            cursor.getValue().writeTo(out);
         }
         out.writeVInt(aliases.size());
-        for (ObjectCursor<AliasMetadata> cursor : aliases.values()) {
-            cursor.value.writeTo(out);
+        for (final AliasMetadata cursor : aliases.values()) {
+            cursor.writeTo(out);
         }
         out.writeOptionalVInt(version);
     }
@@ -259,12 +264,17 @@ public String toString() {
             builder.startObject();
             Builder.toXContentWithTypes(this, builder, ToXContent.EMPTY_PARAMS);
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
     }
 
+    /**
+     * Builder of index template metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private static final Set<String> VALID_FIELDS = Sets.newHashSet(
@@ -286,14 +296,14 @@ public static class Builder {
 
         private Settings settings = Settings.Builder.EMPTY_SETTINGS;
 
-        private final ImmutableOpenMap.Builder<String, CompressedXContent> mappings;
+        private final Map<String, CompressedXContent> mappings;
 
-        private final ImmutableOpenMap.Builder<String, AliasMetadata> aliases;
+        private final Map<String, AliasMetadata> aliases;
 
         public Builder(String name) {
             this.name = name;
-            mappings = ImmutableOpenMap.builder();
-            aliases = ImmutableOpenMap.builder();
+            mappings = new HashMap<>();
+            aliases = new HashMap<>();
         }
 
         public Builder(IndexTemplateMetadata indexTemplateMetadata) {
@@ -303,8 +313,8 @@ public Builder(IndexTemplateMetadata indexTemplateMetadata) {
             patterns(indexTemplateMetadata.patterns());
             settings(indexTemplateMetadata.settings());
 
-            mappings = ImmutableOpenMap.builder(indexTemplateMetadata.mappings);
-            aliases = ImmutableOpenMap.builder(indexTemplateMetadata.aliases());
+            mappings = new HashMap<>(indexTemplateMetadata.mappings);
+            aliases = new HashMap<>(indexTemplateMetadata.aliases());
         }
 
         public Builder order(int order) {
@@ -353,7 +363,7 @@ public Builder putAlias(AliasMetadata.Builder aliasMetadata) {
         }
 
         public IndexTemplateMetadata build() {
-            return new IndexTemplateMetadata(name, order, version, indexPatterns, settings, mappings.build(), aliases.build());
+            return new IndexTemplateMetadata(name, order, version, indexPatterns, settings, mappings, aliases);
         }
 
         /**
@@ -425,8 +435,8 @@ private static void toInnerXContent(
             }
 
             builder.startObject("aliases");
-            for (ObjectCursor<AliasMetadata> cursor : indexTemplateMetadata.aliases().values()) {
-                AliasMetadata.Builder.toXContent(cursor.value, builder, params);
+            for (final AliasMetadata cursor : indexTemplateMetadata.aliases().values()) {
+                AliasMetadata.Builder.toXContent(cursor, builder, params);
             }
             builder.endObject();
         }
@@ -471,7 +481,7 @@ public static IndexTemplateMetadata fromXContent(XContentParser parser, String t
                                 Map<String, Object> mappingSource = MapBuilder.<String, Object>newMapBuilder()
                                     .put(mappingType, parser.mapOrdered())
                                     .map();
-                                builder.putMapping(mappingType, Strings.toString(XContentFactory.jsonBuilder().map(mappingSource)));
+                                builder.putMapping(mappingType, XContentFactory.jsonBuilder().map(mappingSource).toString());
                             }
                         }
                     } else if ("aliases".equals(currentFieldName)) {
@@ -487,7 +497,7 @@ public static IndexTemplateMetadata fromXContent(XContentParser parser, String t
                             Map<String, Object> mapping = parser.mapOrdered();
                             if (mapping.size() == 1) {
                                 String mappingType = mapping.keySet().iterator().next();
-                                String mappingSource = Strings.toString(XContentFactory.jsonBuilder().map(mapping));
+                                String mappingSource = XContentFactory.jsonBuilder().map(mapping).toString();
 
                                 if (mappingSource == null) {
                                     // crap, no mapping source, warn?
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/Manifest.java b/server/src/main/java/org/opensearch/cluster/metadata/Manifest.java
index 8205886cf9df6..79a8f4fb95f51 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/Manifest.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/Manifest.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.index.Index;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -55,6 +55,8 @@
  * When new version of metadata is written it's assigned some generation long value.
  * Global metadata generation could be obtained by calling {@link #getGlobalGeneration()}.
  * Index metadata generation could be obtained by calling {@link #getIndexGenerations()}.
+ *
+ * @opensearch.internal
  */
 public class Manifest implements ToXContentFragment {
     // TODO revisit missing and unknown constants once Zen2 BWC is ready
@@ -231,6 +233,11 @@ public boolean isGlobalGenerationMissing() {
         return globalGeneration == MISSING_GLOBAL_GENERATION;
     }
 
+    /**
+     * An index entry.
+     *
+     * @opensearch.internal
+     */
     private static final class IndexEntry implements ToXContentFragment {
         private static final ParseField INDEX_GENERATION_PARSE_FIELD = new ParseField("generation");
         private static final ParseField INDEX_PARSE_FIELD = new ParseField("index");
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MappingMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/MappingMetadata.java
index 620542f8f1bde..89eda77648021 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MappingMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MappingMetadata.java
@@ -36,13 +36,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperService;
 
@@ -56,6 +56,8 @@
 
 /**
  * Mapping configuration for a type.
+ *
+ * @opensearch.internal
  */
 public class MappingMetadata extends AbstractDiffable<MappingMetadata> {
     public static final MappingMetadata EMPTY_MAPPINGS = new MappingMetadata(MapperService.SINGLE_MAPPING_NAME, Collections.emptyMap());
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java b/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java
index 6e9c30877f9c2..e7dcf10fe6ca2 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java
@@ -32,12 +32,8 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.ObjectHashSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.AliasesRequest;
@@ -51,28 +47,28 @@
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.HppcMaps;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.plugins.MapperPlugin;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -89,6 +85,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.SortedMap;
+import java.util.Spliterators;
 import java.util.TreeMap;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -99,14 +96,40 @@
 import static org.opensearch.common.settings.Settings.readSettingsFromStream;
 import static org.opensearch.common.settings.Settings.writeSettingsToStream;
 
+/**
+ * Metadata information
+ *
+ * @opensearch.internal
+ */
 public class Metadata implements Iterable<IndexMetadata>, Diffable<Metadata>, ToXContentFragment {
 
     private static final Logger logger = LogManager.getLogger(Metadata.class);
 
     public static final String ALL = "_all";
-    public static final String UNKNOWN_CLUSTER_UUID = "_na_";
+    public static final String UNKNOWN_CLUSTER_UUID = Strings.UNKNOWN_UUID_VALUE;
     public static final Pattern NUMBER_PATTERN = Pattern.compile("[0-9]+$");
 
+    /**
+     * Utility to identify whether input index uses SEGMENT replication strategy in established cluster state metadata.
+     * Note: Method intended for use by other plugins as well.
+     *
+     * @param indexName Index name
+     * @return true if index uses SEGMENT replication, false otherwise
+     */
+    public boolean isSegmentReplicationEnabled(String indexName) {
+        return Optional.ofNullable(index(indexName))
+            .map(
+                indexMetadata -> ReplicationType.parseString(indexMetadata.getSettings().get(IndexMetadata.SETTING_REPLICATION_TYPE))
+                    .equals(ReplicationType.SEGMENT)
+            )
+            .orElse(false);
+    }
+
+    /**
+     * Context of the XContent.
+     *
+     * @opensearch.internal
+     */
     public enum XContentContext {
         /* Custom metadata should be returns as part of API call */
         API,
@@ -141,11 +164,23 @@ public enum XContentContext {
      */
     public static EnumSet<XContentContext> ALL_CONTEXTS = EnumSet.allOf(XContentContext.class);
 
+    /**
+     * Custom metadata.
+     *
+     * @opensearch.internal
+     */
     public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, ClusterState.FeatureAware {
 
         EnumSet<XContentContext> context();
     }
 
+    public static final Setting<Integer> DEFAULT_REPLICA_COUNT_SETTING = Setting.intSetting(
+        "cluster.default_number_of_replicas",
+        1,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     public static final Setting<Boolean> SETTING_READ_ONLY_SETTING = Setting.boolSetting(
         "cluster.blocks.read_only",
         false,
@@ -163,6 +198,16 @@ public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, Clust
         EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE)
     );
 
+    public static final ClusterBlock CLUSTER_CREATE_INDEX_BLOCK = new ClusterBlock(
+        10,
+        "cluster create-index blocked (api)",
+        false,
+        false,
+        false,
+        RestStatus.FORBIDDEN,
+        EnumSet.of(ClusterBlockLevel.CREATE_INDEX)
+    );
+
     public static final Setting<Boolean> SETTING_READ_ONLY_ALLOW_DELETE_SETTING = Setting.boolSetting(
         "cluster.blocks.read_only_allow_delete",
         false,
@@ -170,6 +215,13 @@ public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, Clust
         Property.NodeScope
     );
 
+    public static final Setting<Boolean> SETTING_CREATE_INDEX_BLOCK_SETTING = Setting.boolSetting(
+        "cluster.blocks.create_index",
+        false,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     public static final ClusterBlock CLUSTER_READ_ONLY_ALLOW_DELETE_BLOCK = new ClusterBlock(
         13,
         "cluster read-only / allow delete (api)",
@@ -204,9 +256,9 @@ public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, Clust
     private final Settings persistentSettings;
     private final Settings settings;
     private final DiffableStringMap hashesOfConsistentSettings;
-    private final ImmutableOpenMap<String, IndexMetadata> indices;
-    private final ImmutableOpenMap<String, IndexTemplateMetadata> templates;
-    private final ImmutableOpenMap<String, Custom> customs;
+    private final Map<String, IndexMetadata> indices;
+    private final Map<String, IndexTemplateMetadata> templates;
+    private final Map<String, Custom> customs;
 
     private final transient int totalNumberOfShards; // Transient ? not serializable anyway?
     private final int totalOpenIndexShards;
@@ -228,9 +280,9 @@ public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, Clust
         Settings transientSettings,
         Settings persistentSettings,
         DiffableStringMap hashesOfConsistentSettings,
-        ImmutableOpenMap<String, IndexMetadata> indices,
-        ImmutableOpenMap<String, IndexTemplateMetadata> templates,
-        ImmutableOpenMap<String, Custom> customs,
+        final Map<String, IndexMetadata> indices,
+        final Map<String, IndexTemplateMetadata> templates,
+        final Map<String, Custom> customs,
         String[] allIndices,
         String[] visibleIndices,
         String[] allOpenIndices,
@@ -247,15 +299,15 @@ public interface Custom extends NamedDiffable<Custom>, ToXContentFragment, Clust
         this.persistentSettings = persistentSettings;
         this.settings = Settings.builder().put(persistentSettings).put(transientSettings).build();
         this.hashesOfConsistentSettings = hashesOfConsistentSettings;
-        this.indices = indices;
-        this.customs = customs;
-        this.templates = templates;
+        this.indices = Collections.unmodifiableMap(indices);
+        this.customs = Collections.unmodifiableMap(customs);
+        this.templates = Collections.unmodifiableMap(templates);
         int totalNumberOfShards = 0;
         int totalOpenIndexShards = 0;
-        for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
-            totalNumberOfShards += cursor.value.getTotalNumberOfShards();
-            if (IndexMetadata.State.OPEN.equals(cursor.value.getState())) {
-                totalOpenIndexShards += cursor.value.getTotalNumberOfShards();
+        for (IndexMetadata cursor : indices.values()) {
+            totalNumberOfShards += cursor.getTotalNumberOfShards();
+            if (IndexMetadata.State.OPEN.equals(cursor.getState())) {
+                totalOpenIndexShards += cursor.getTotalNumberOfShards();
             }
         }
         this.totalNumberOfShards = totalNumberOfShards;
@@ -319,8 +371,7 @@ public boolean hasAlias(String alias) {
     }
 
     public boolean equalsAliases(Metadata other) {
-        for (ObjectCursor<IndexMetadata> cursor : other.indices().values()) {
-            IndexMetadata otherIndex = cursor.value;
+        for (IndexMetadata otherIndex : other.indices().values()) {
             IndexMetadata thisIndex = index(otherIndex.getIndex());
             if (thisIndex == null) {
                 return false;
@@ -345,7 +396,7 @@ public SortedMap<String, IndexAbstraction> getIndicesLookup() {
      * @return A map of index name to the list of aliases metadata. If a concrete index does not have matching
      * aliases then the result will <b>not</b> include the index's key.
      */
-    public ImmutableOpenMap<String, List<AliasMetadata>> findAllAliases(final String[] concreteIndices) {
+    public Map<String, List<AliasMetadata>> findAllAliases(final String[] concreteIndices) {
         return findAliases(Strings.EMPTY_ARRAY, concreteIndices);
     }
 
@@ -358,7 +409,7 @@ public ImmutableOpenMap<String, List<AliasMetadata>> findAllAliases(final String
      * @return A map of index name to the list of aliases metadata. If a concrete index does not have matching
      * aliases then the result will <b>not</b> include the index's key.
      */
-    public ImmutableOpenMap<String, List<AliasMetadata>> findAliases(final AliasesRequest aliasesRequest, final String[] concreteIndices) {
+    public Map<String, List<AliasMetadata>> findAliases(final AliasesRequest aliasesRequest, final String[] concreteIndices) {
         return findAliases(aliasesRequest.aliases(), concreteIndices);
     }
 
@@ -371,11 +422,11 @@ public ImmutableOpenMap<String, List<AliasMetadata>> findAliases(final AliasesRe
      * @return A map of index name to the list of aliases metadata. If a concrete index does not have matching
      * aliases then the result will <b>not</b> include the index's key.
      */
-    private ImmutableOpenMap<String, List<AliasMetadata>> findAliases(final String[] aliases, final String[] concreteIndices) {
+    private Map<String, List<AliasMetadata>> findAliases(final String[] aliases, final String[] concreteIndices) {
         assert aliases != null;
         assert concreteIndices != null;
         if (concreteIndices.length == 0) {
-            return ImmutableOpenMap.of();
+            return Map.of();
         }
         String[] patterns = new String[aliases.length];
         boolean[] include = new boolean[aliases.length];
@@ -390,12 +441,11 @@ private ImmutableOpenMap<String, List<AliasMetadata>> findAliases(final String[]
             }
         }
         boolean matchAllAliases = patterns.length == 0;
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> mapBuilder = ImmutableOpenMap.builder();
+        final Map<String, List<AliasMetadata>> mapBuilder = new HashMap<>();
         for (String index : concreteIndices) {
             IndexMetadata indexMetadata = indices.get(index);
             List<AliasMetadata> filteredValues = new ArrayList<>();
-            for (ObjectCursor<AliasMetadata> cursor : indexMetadata.getAliases().values()) {
-                AliasMetadata value = cursor.value;
+            for (final AliasMetadata value : indexMetadata.getAliases().values()) {
                 boolean matched = matchAllAliases;
                 String alias = value.alias();
                 for (int i = 0; i < patterns.length; i++) {
@@ -418,39 +468,7 @@ private ImmutableOpenMap<String, List<AliasMetadata>> findAliases(final String[]
                 mapBuilder.put(index, Collections.unmodifiableList(filteredValues));
             }
         }
-        return mapBuilder.build();
-    }
-
-    /**
-     * Checks if at least one of the specified aliases exists in the specified concrete indices. Wildcards are supported in the
-     * alias names for partial matches.
-     *
-     * @param aliases         The names of the index aliases to find
-     * @param concreteIndices The concrete indexes the index aliases must point to order to be returned.
-     * @return whether at least one of the specified aliases exists in one of the specified concrete indices.
-     */
-    public boolean hasAliases(final String[] aliases, String[] concreteIndices) {
-        assert aliases != null;
-        assert concreteIndices != null;
-        if (concreteIndices.length == 0) {
-            return false;
-        }
-
-        Iterable<String> intersection = HppcMaps.intersection(ObjectHashSet.from(concreteIndices), indices.keys());
-        for (String index : intersection) {
-            IndexMetadata indexMetadata = indices.get(index);
-            List<AliasMetadata> filteredValues = new ArrayList<>();
-            for (ObjectCursor<AliasMetadata> cursor : indexMetadata.getAliases().values()) {
-                AliasMetadata value = cursor.value;
-                if (Regex.simpleMatch(aliases, value.alias())) {
-                    filteredValues.add(value);
-                }
-            }
-            if (!filteredValues.isEmpty()) {
-                return true;
-            }
-        }
-        return false;
+        return mapBuilder;
     }
 
     /**
@@ -461,29 +479,27 @@ public boolean hasAliases(final String[] aliases, String[] concreteIndices) {
      * @see MapperPlugin#getFieldFilter()
      *
      */
-    public ImmutableOpenMap<String, MappingMetadata> findMappings(String[] concreteIndices, Function<String, Predicate<String>> fieldFilter)
+    public Map<String, MappingMetadata> findMappings(String[] concreteIndices, Function<String, Predicate<String>> fieldFilter)
         throws IOException {
         assert concreteIndices != null;
         if (concreteIndices.length == 0) {
-            return ImmutableOpenMap.of();
+            return Map.of();
         }
 
-        ImmutableOpenMap.Builder<String, MappingMetadata> indexMapBuilder = ImmutableOpenMap.builder();
-        Iterable<String> intersection = HppcMaps.intersection(ObjectHashSet.from(concreteIndices), indices.keys());
-        for (String index : intersection) {
-            IndexMetadata indexMetadata = indices.get(index);
-            Predicate<String> fieldPredicate = fieldFilter.apply(index);
-            indexMapBuilder.put(index, filterFields(indexMetadata.mapping(), fieldPredicate));
-        }
-        return indexMapBuilder.build();
+        final Map<String, MappingMetadata> indexMapBuilder = new HashMap<>();
+        Arrays.stream(concreteIndices)
+            .filter(indices.keySet()::contains)
+            .forEach((idx) -> indexMapBuilder.put(idx, filterFields(indices.get(idx).mapping(), fieldFilter.apply(idx))));
+
+        return Collections.unmodifiableMap(indexMapBuilder);
     }
 
     /**
      * Finds the parent data streams, if any, for the specified concrete indices.
      */
-    public ImmutableOpenMap<String, IndexAbstraction.DataStream> findDataStreams(String[] concreteIndices) {
+    public Map<String, IndexAbstraction.DataStream> findDataStreams(String[] concreteIndices) {
         assert concreteIndices != null;
-        final ImmutableOpenMap.Builder<String, IndexAbstraction.DataStream> builder = ImmutableOpenMap.builder();
+        final Map<String, IndexAbstraction.DataStream> builder = new HashMap<>();
         final SortedMap<String, IndexAbstraction> lookup = getIndicesLookup();
         for (String indexName : concreteIndices) {
             IndexAbstraction index = lookup.get(indexName);
@@ -493,7 +509,7 @@ public ImmutableOpenMap<String, IndexAbstraction.DataStream> findDataStreams(Str
                 builder.put(indexName, index.getParentDataStream());
             }
         }
-        return builder.build();
+        return Collections.unmodifiableMap(builder);
     }
 
     @SuppressWarnings("unchecked")
@@ -778,20 +794,20 @@ public IndexMetadata getIndexSafe(Index index) {
         throw new IndexNotFoundException(index);
     }
 
-    public ImmutableOpenMap<String, IndexMetadata> indices() {
+    public Map<String, IndexMetadata> indices() {
         return this.indices;
     }
 
-    public ImmutableOpenMap<String, IndexMetadata> getIndices() {
+    public Map<String, IndexMetadata> getIndices() {
         return indices();
     }
 
-    public ImmutableOpenMap<String, IndexTemplateMetadata> templates() {
+    public Map<String, IndexTemplateMetadata> templates() {
         return this.templates;
     }
 
-    public ImmutableOpenMap<String, IndexTemplateMetadata> getTemplates() {
-        return this.templates;
+    public Map<String, IndexTemplateMetadata> getTemplates() {
+        return templates();
     }
 
     public Map<String, ComponentTemplate> componentTemplates() {
@@ -812,14 +828,18 @@ public Map<String, DataStream> dataStreams() {
             .orElse(Collections.emptyMap());
     }
 
-    public ImmutableOpenMap<String, Custom> customs() {
-        return this.customs;
+    public DecommissionAttributeMetadata decommissionAttributeMetadata() {
+        return custom(DecommissionAttributeMetadata.TYPE);
     }
 
-    public ImmutableOpenMap<String, Custom> getCustoms() {
+    public Map<String, Custom> customs() {
         return this.customs;
     }
 
+    public Map<String, Custom> getCustoms() {
+        return this.customs();
+    }
+
     /**
      * The collection of index deletions in the cluster.
      */
@@ -827,6 +847,14 @@ public IndexGraveyard indexGraveyard() {
         return custom(IndexGraveyard.TYPE);
     }
 
+    /**
+     * *
+     * @return The weighted routing metadata for search requests
+     */
+    public WeightedRoutingMetadata weightedRoutingMetadata() {
+        return custom(WeightedRoutingMetadata.TYPE);
+    }
+
     public <T extends Custom> T custom(String type) {
         return (T) customs.get(type);
     }
@@ -888,7 +916,7 @@ public boolean routingRequired(String concreteIndex) {
 
     @Override
     public Iterator<IndexMetadata> iterator() {
-        return indices.valuesIt();
+        return indices.values().iterator();
     }
 
     public static boolean isGlobalStateEquals(Metadata metadata1, Metadata metadata2) {
@@ -912,15 +940,15 @@ public static boolean isGlobalStateEquals(Metadata metadata1, Metadata metadata2
         }
         // Check if any persistent metadata needs to be saved
         int customCount1 = 0;
-        for (ObjectObjectCursor<String, Custom> cursor : metadata1.customs) {
-            if (cursor.value.context().contains(XContentContext.GATEWAY)) {
-                if (!cursor.value.equals(metadata2.custom(cursor.key))) return false;
+        for (Map.Entry<String, Custom> cursor : metadata1.customs.entrySet()) {
+            if (cursor.getValue().context().contains(XContentContext.GATEWAY)) {
+                if (!cursor.getValue().equals(metadata2.custom(cursor.getKey()))) return false;
                 customCount1++;
             }
         }
         int customCount2 = 0;
-        for (ObjectCursor<Custom> cursor : metadata2.customs.values()) {
-            if (cursor.value.context().contains(XContentContext.GATEWAY)) {
+        for (final Custom cursor : metadata2.customs.values()) {
+            if (cursor.context().contains(XContentContext.GATEWAY)) {
                 customCount2++;
             }
         }
@@ -947,6 +975,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * A diff of metadata.
+     *
+     * @opensearch.internal
+     */
     private static class MetadataDiff implements Diff<Metadata> {
 
         private final long version;
@@ -956,9 +989,9 @@ private static class MetadataDiff implements Diff<Metadata> {
         private final Settings transientSettings;
         private final Settings persistentSettings;
         private final Diff<DiffableStringMap> hashesOfConsistentSettings;
-        private final Diff<ImmutableOpenMap<String, IndexMetadata>> indices;
-        private final Diff<ImmutableOpenMap<String, IndexTemplateMetadata>> templates;
-        private final Diff<ImmutableOpenMap<String, Custom>> customs;
+        private final Diff<Map<String, IndexMetadata>> indices;
+        private final Diff<Map<String, IndexTemplateMetadata>> templates;
+        private final Diff<Map<String, Custom>> customs;
 
         MetadataDiff(Metadata before, Metadata after) {
             clusterUUID = after.clusterUUID;
@@ -996,9 +1029,9 @@ private static class MetadataDiff implements Diff<Metadata> {
             } else {
                 hashesOfConsistentSettings = DiffableStringMap.DiffableStringMapDiff.EMPTY;
             }
-            indices = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), INDEX_METADATA_DIFF_VALUE_READER);
-            templates = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), TEMPLATES_DIFF_VALUE_READER);
-            customs = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
+            indices = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), INDEX_METADATA_DIFF_VALUE_READER);
+            templates = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), TEMPLATES_DIFF_VALUE_READER);
+            customs = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), CUSTOM_VALUE_SERIALIZER);
         }
 
         @Override
@@ -1089,20 +1122,20 @@ public void writeTo(StreamOutput out) throws IOException {
             indexMetadata.writeTo(out);
         }
         out.writeVInt(templates.size());
-        for (ObjectCursor<IndexTemplateMetadata> cursor : templates.values()) {
-            cursor.value.writeTo(out);
+        for (final IndexTemplateMetadata cursor : templates.values()) {
+            cursor.writeTo(out);
         }
         // filter out custom states not supported by the other node
         int numberOfCustoms = 0;
-        for (final ObjectCursor<Custom> cursor : customs.values()) {
-            if (FeatureAware.shouldSerialize(out, cursor.value)) {
+        for (final Custom cursor : customs.values()) {
+            if (FeatureAware.shouldSerialize(out, cursor)) {
                 numberOfCustoms++;
             }
         }
         out.writeVInt(numberOfCustoms);
-        for (final ObjectCursor<Custom> cursor : customs.values()) {
-            if (FeatureAware.shouldSerialize(out, cursor.value)) {
-                out.writeNamedWriteable(cursor.value);
+        for (final Custom cursor : customs.values()) {
+            if (FeatureAware.shouldSerialize(out, cursor)) {
+                out.writeNamedWriteable(cursor);
             }
         }
     }
@@ -1115,6 +1148,11 @@ public static Builder builder(Metadata metadata) {
         return new Builder(metadata);
     }
 
+    /**
+     * Builder of metadata.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private String clusterUUID;
@@ -1126,15 +1164,17 @@ public static class Builder {
         private Settings persistentSettings = Settings.Builder.EMPTY_SETTINGS;
         private DiffableStringMap hashesOfConsistentSettings = new DiffableStringMap(Collections.emptyMap());
 
-        private final ImmutableOpenMap.Builder<String, IndexMetadata> indices;
-        private final ImmutableOpenMap.Builder<String, IndexTemplateMetadata> templates;
-        private final ImmutableOpenMap.Builder<String, Custom> customs;
+        private final Map<String, IndexMetadata> indices;
+        private final Map<String, IndexTemplateMetadata> templates;
+        private final Map<String, Custom> customs;
+        private final Metadata previousMetadata;
 
         public Builder() {
             clusterUUID = UNKNOWN_CLUSTER_UUID;
-            indices = ImmutableOpenMap.builder();
-            templates = ImmutableOpenMap.builder();
-            customs = ImmutableOpenMap.builder();
+            indices = new HashMap<>();
+            templates = new HashMap<>();
+            customs = new HashMap<>();
+            previousMetadata = null;
             indexGraveyard(IndexGraveyard.builder().build()); // create new empty index graveyard to initialize
         }
 
@@ -1146,9 +1186,10 @@ public Builder(Metadata metadata) {
             this.persistentSettings = metadata.persistentSettings;
             this.hashesOfConsistentSettings = metadata.hashesOfConsistentSettings;
             this.version = metadata.version;
-            this.indices = ImmutableOpenMap.builder(metadata.indices);
-            this.templates = ImmutableOpenMap.builder(metadata.templates);
-            this.customs = ImmutableOpenMap.builder(metadata.customs);
+            this.indices = new HashMap<>(metadata.indices);
+            this.templates = new HashMap<>(metadata.templates);
+            this.customs = new HashMap<>(metadata.customs);
+            this.previousMetadata = metadata;
         }
 
         public Builder put(IndexMetadata.Builder indexMetadataBuilder) {
@@ -1201,7 +1242,7 @@ public Builder removeAllIndices() {
             return this;
         }
 
-        public Builder indices(ImmutableOpenMap<String, IndexMetadata> indices) {
+        public Builder indices(final Map<String, IndexMetadata> indices) {
             this.indices.putAll(indices);
             return this;
         }
@@ -1220,14 +1261,13 @@ public Builder removeTemplate(String templateName) {
             return this;
         }
 
-        public Builder templates(ImmutableOpenMap<String, IndexTemplateMetadata> templates) {
+        public Builder templates(Map<String, IndexTemplateMetadata> templates) {
             this.templates.putAll(templates);
             return this;
         }
 
         public Builder put(String name, ComponentTemplate componentTemplate) {
             Objects.requireNonNull(componentTemplate, "it is invalid to add a null component template: " + name);
-            // ಠ_ಠ at ImmutableOpenMap
             Map<String, ComponentTemplate> existingTemplates = Optional.ofNullable(
                 (ComponentTemplateMetadata) this.customs.get(ComponentTemplateMetadata.TYPE)
             ).map(ctm -> new HashMap<>(ctm.componentTemplates())).orElse(new HashMap<>());
@@ -1237,7 +1277,6 @@ public Builder put(String name, ComponentTemplate componentTemplate) {
         }
 
         public Builder removeComponentTemplate(String name) {
-            // ಠ_ಠ at ImmutableOpenMap
             Map<String, ComponentTemplate> existingTemplates = Optional.ofNullable(
                 (ComponentTemplateMetadata) this.customs.get(ComponentTemplateMetadata.TYPE)
             ).map(ctm -> new HashMap<>(ctm.componentTemplates())).orElse(new HashMap<>());
@@ -1258,7 +1297,6 @@ public Builder indexTemplates(Map<String, ComposableIndexTemplate> indexTemplate
 
         public Builder put(String name, ComposableIndexTemplate indexTemplate) {
             Objects.requireNonNull(indexTemplate, "it is invalid to add a null index template: " + name);
-            // ಠ_ಠ at ImmutableOpenMap
             Map<String, ComposableIndexTemplate> existingTemplates = Optional.ofNullable(
                 (ComposableIndexTemplateMetadata) this.customs.get(ComposableIndexTemplateMetadata.TYPE)
             ).map(itmd -> new HashMap<>(itmd.indexTemplates())).orElse(new HashMap<>());
@@ -1268,7 +1306,6 @@ public Builder put(String name, ComposableIndexTemplate indexTemplate) {
         }
 
         public Builder removeIndexTemplate(String name) {
-            // ಠ_ಠ at ImmutableOpenMap
             Map<String, ComposableIndexTemplate> existingTemplates = Optional.ofNullable(
                 (ComposableIndexTemplateMetadata) this.customs.get(ComposableIndexTemplateMetadata.TYPE)
             ).map(itmd -> new HashMap<>(itmd.indexTemplates())).orElse(new HashMap<>());
@@ -1319,8 +1356,9 @@ public Builder removeCustom(String type) {
             return this;
         }
 
-        public Builder customs(ImmutableOpenMap<String, Custom> customs) {
-            StreamSupport.stream(customs.spliterator(), false).forEach(cursor -> Objects.requireNonNull(cursor.value, cursor.key));
+        public Builder customs(Map<String, Custom> customs) {
+            StreamSupport.stream(Spliterators.spliterator(customs.entrySet(), 0), false)
+                .forEach(cursor -> Objects.requireNonNull(cursor.getValue(), cursor.getKey()));
             this.customs.putAll(customs);
             return this;
         }
@@ -1335,9 +1373,18 @@ public IndexGraveyard indexGraveyard() {
             return graveyard;
         }
 
+        public Builder decommissionAttributeMetadata(final DecommissionAttributeMetadata decommissionAttributeMetadata) {
+            putCustom(DecommissionAttributeMetadata.TYPE, decommissionAttributeMetadata);
+            return this;
+        }
+
+        public DecommissionAttributeMetadata decommissionAttributeMetadata() {
+            return (DecommissionAttributeMetadata) getCustom(DecommissionAttributeMetadata.TYPE);
+        }
+
         public Builder updateSettings(Settings settings, String... indices) {
             if (indices == null || indices.length == 0) {
-                indices = this.indices.keys().toArray(String.class);
+                indices = this.indices.keySet().toArray(new String[0]);
             }
             for (String index : indices) {
                 IndexMetadata indexMetadata = this.indices.get(index);
@@ -1427,6 +1474,44 @@ public Builder generateClusterUuidIfNeeded() {
         }
 
         public Metadata build() {
+            DataStreamMetadata dataStreamMetadata = (DataStreamMetadata) this.customs.get(DataStreamMetadata.TYPE);
+            DataStreamMetadata previousDataStreamMetadata = (previousMetadata != null)
+                ? (DataStreamMetadata) this.previousMetadata.customs.get(DataStreamMetadata.TYPE)
+                : null;
+
+            boolean recomputeRequiredforIndicesLookups = (previousMetadata == null)
+                || (indices.equals(previousMetadata.indices) == false)
+                || (previousDataStreamMetadata != null && previousDataStreamMetadata.equals(dataStreamMetadata) == false)
+                || (dataStreamMetadata != null && dataStreamMetadata.equals(previousDataStreamMetadata) == false);
+
+            return (recomputeRequiredforIndicesLookups == false)
+                ? buildMetadataWithPreviousIndicesLookups()
+                : buildMetadataWithRecomputedIndicesLookups();
+        }
+
+        protected Metadata buildMetadataWithPreviousIndicesLookups() {
+            return new Metadata(
+                clusterUUID,
+                clusterUUIDCommitted,
+                version,
+                coordinationMetadata,
+                transientSettings,
+                persistentSettings,
+                hashesOfConsistentSettings,
+                indices,
+                templates,
+                customs,
+                Arrays.copyOf(previousMetadata.allIndices, previousMetadata.allIndices.length),
+                Arrays.copyOf(previousMetadata.visibleIndices, previousMetadata.visibleIndices.length),
+                Arrays.copyOf(previousMetadata.allOpenIndices, previousMetadata.allOpenIndices.length),
+                Arrays.copyOf(previousMetadata.visibleOpenIndices, previousMetadata.visibleOpenIndices.length),
+                Arrays.copyOf(previousMetadata.allClosedIndices, previousMetadata.allClosedIndices.length),
+                Arrays.copyOf(previousMetadata.visibleClosedIndices, previousMetadata.visibleClosedIndices.length),
+                Collections.unmodifiableSortedMap(previousMetadata.indicesLookup)
+            );
+        }
+
+        protected Metadata buildMetadataWithRecomputedIndicesLookups() {
             // TODO: We should move these datastructures to IndexNameExpressionResolver, this will give the following benefits:
             // 1) The datastructures will be rebuilt only when needed. Now during serializing we rebuild these datastructures
             // while these datastructures aren't even used.
@@ -1439,8 +1524,7 @@ public Metadata build() {
             final List<String> allClosedIndices = new ArrayList<>();
             final List<String> visibleClosedIndices = new ArrayList<>();
             final Set<String> allAliases = new HashSet<>();
-            for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
-                final IndexMetadata indexMetadata = cursor.value;
+            for (final IndexMetadata indexMetadata : indices.values()) {
                 final String name = indexMetadata.getIndex().getName();
                 boolean added = allIndices.add(name);
                 assert added : "double index named [" + name + "]";
@@ -1459,7 +1543,7 @@ public Metadata build() {
                         visibleClosedIndices.add(name);
                     }
                 }
-                indexMetadata.getAliases().keysIt().forEachRemaining(allAliases::add);
+                indexMetadata.getAliases().keySet().iterator().forEachRemaining(allAliases::add);
             }
 
             final Set<String> allDataStreams = new HashSet<>();
@@ -1475,10 +1559,10 @@ public Metadata build() {
             ArrayList<String> duplicates = new ArrayList<>();
             if (aliasDuplicatesWithIndices.isEmpty() == false) {
                 // iterate again and constructs a helpful message
-                for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
+                for (final IndexMetadata cursor : indices.values()) {
                     for (String alias : aliasDuplicatesWithIndices) {
-                        if (cursor.value.getAliases().containsKey(alias)) {
-                            duplicates.add(alias + " (alias of " + cursor.value.getIndex() + ") conflicts with index");
+                        if (cursor.getAliases().containsKey(alias)) {
+                            duplicates.add(alias + " (alias of " + cursor.getIndex() + ") conflicts with index");
                         }
                     }
                 }
@@ -1488,10 +1572,10 @@ public Metadata build() {
             aliasDuplicatesWithDataStreams.retainAll(allDataStreams);
             if (aliasDuplicatesWithDataStreams.isEmpty() == false) {
                 // iterate again and constructs a helpful message
-                for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
+                for (final IndexMetadata cursor : indices.values()) {
                     for (String alias : aliasDuplicatesWithDataStreams) {
-                        if (cursor.value.getAliases().containsKey(alias)) {
-                            duplicates.add(alias + " (alias of " + cursor.value.getIndex() + ") conflicts with data stream");
+                        if (cursor.getAliases().containsKey(alias)) {
+                            duplicates.add(alias + " (alias of " + cursor.getIndex() + ") conflicts with data stream");
                         }
                     }
                 }
@@ -1537,9 +1621,9 @@ public Metadata build() {
                 transientSettings,
                 persistentSettings,
                 hashesOfConsistentSettings,
-                indices.build(),
-                templates.build(),
-                customs.build(),
+                indices,
+                templates,
+                customs,
                 allIndicesArray,
                 visibleIndicesArray,
                 allOpenIndicesArray,
@@ -1576,9 +1660,7 @@ private SortedMap<String, IndexAbstraction> buildIndicesLookup() {
                 }
             }
 
-            for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
-                IndexMetadata indexMetadata = cursor.value;
-
+            for (final IndexMetadata indexMetadata : indices.values()) {
                 IndexAbstraction.Index index;
                 DataStream parent = indexToDataStreamLookup.get(indexMetadata.getIndex().getName());
                 if (parent != null) {
@@ -1591,8 +1673,7 @@ private SortedMap<String, IndexAbstraction> buildIndicesLookup() {
                 IndexAbstraction existing = indicesLookup.put(indexMetadata.getIndex().getName(), index);
                 assert existing == null : "duplicate for " + indexMetadata.getIndex();
 
-                for (ObjectObjectCursor<String, AliasMetadata> aliasCursor : indexMetadata.getAliases()) {
-                    AliasMetadata aliasMetadata = aliasCursor.value;
+                for (final AliasMetadata aliasMetadata : indexMetadata.getAliases().values()) {
                     indicesLookup.compute(aliasMetadata.getAlias(), (aliasName, alias) -> {
                         if (alias == null) {
                             return new IndexAbstraction.Alias(aliasMetadata, indexMetadata);
@@ -1675,8 +1756,8 @@ public static void toXContent(Metadata metadata, XContentBuilder builder, ToXCon
             }
 
             builder.startObject("templates");
-            for (ObjectCursor<IndexTemplateMetadata> cursor : metadata.templates().values()) {
-                IndexTemplateMetadata.Builder.toXContentWithTypes(cursor.value, builder, params);
+            for (final IndexTemplateMetadata cursor : metadata.templates().values()) {
+                IndexTemplateMetadata.Builder.toXContentWithTypes(cursor, builder, params);
             }
             builder.endObject();
 
@@ -1688,10 +1769,10 @@ public static void toXContent(Metadata metadata, XContentBuilder builder, ToXCon
                 builder.endObject();
             }
 
-            for (ObjectObjectCursor<String, Custom> cursor : metadata.customs()) {
-                if (cursor.value.context().contains(context)) {
-                    builder.startObject(cursor.key);
-                    cursor.value.toXContent(builder, params);
+            for (final Map.Entry<String, Custom> cursor : metadata.customs().entrySet()) {
+                if (cursor.getValue().context().contains(context)) {
+                    builder.startObject(cursor.getKey());
+                    cursor.getValue().toXContent(builder, params);
                     builder.endObject();
                 }
             }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateDataStreamService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateDataStreamService.java
index 13e470eed617d..9ca244660663b 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateDataStreamService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateDataStreamService.java
@@ -36,7 +36,6 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchStatusException;
 import org.opensearch.ResourceAlreadyExistsException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.create.CreateIndexClusterStateUpdateRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.ActiveShardsObserver;
@@ -45,15 +44,18 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateRequest;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ObjectPath;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectPath;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.MetadataFieldMapper;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -62,6 +64,11 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 
+/**
+ * Creates a data stream of metadata
+ *
+ * @opensearch.internal
+ */
 public class MetadataCreateDataStreamService {
 
     private static final Logger logger = LogManager.getLogger(MetadataCreateDataStreamService.class);
@@ -69,6 +76,7 @@ public class MetadataCreateDataStreamService {
     private final ClusterService clusterService;
     private final ActiveShardsObserver activeShardsObserver;
     private final MetadataCreateIndexService metadataCreateIndexService;
+    private final ClusterManagerTaskThrottler.ThrottlingKey createDataStreamTaskKey;
 
     public MetadataCreateDataStreamService(
         ThreadPool threadPool,
@@ -78,6 +86,8 @@ public MetadataCreateDataStreamService(
         this.clusterService = clusterService;
         this.activeShardsObserver = new ActiveShardsObserver(clusterService, threadPool);
         this.metadataCreateIndexService = metadataCreateIndexService;
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        createDataStreamTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_DATA_STREAM_KEY, true);
     }
 
     public void createDataStream(CreateDataStreamClusterStateUpdateRequest request, ActionListener<AcknowledgedResponse> finalListener) {
@@ -90,7 +100,9 @@ public void createDataStream(CreateDataStreamClusterStateUpdateRequest request,
                     new String[] { firstBackingIndexName },
                     ActiveShardCount.DEFAULT,
                     request.masterNodeTimeout(),
-                    shardsAcked -> { finalListener.onResponse(new AcknowledgedResponse(true)); },
+                    shardsAcked -> {
+                        finalListener.onResponse(new AcknowledgedResponse(true));
+                    },
                     finalListener::onFailure
                 );
             } else {
@@ -108,6 +120,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                     return clusterState;
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return createDataStreamTaskKey;
+                }
+
                 @Override
                 protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                     return new ClusterStateUpdateResponse(acknowledged);
@@ -120,6 +137,11 @@ public ClusterState createDataStream(CreateDataStreamClusterStateUpdateRequest r
         return createDataStream(metadataCreateIndexService, current, request);
     }
 
+    /**
+     * A request to create a data stream cluster state update
+     *
+     * @opensearch.internal
+     */
     public static final class CreateDataStreamClusterStateUpdateRequest extends ClusterStateUpdateRequest {
 
         private final String name;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateIndexService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateIndexService.java
index cb76b7217624f..1f16fdd380cfc 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateIndexService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateIndexService.java
@@ -40,7 +40,6 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.create.CreateIndexClusterStateUpdateRequest;
 import org.opensearch.action.admin.indices.shrink.ResizeType;
@@ -59,22 +58,28 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.ValidationException;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
@@ -84,12 +89,15 @@
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.shard.IndexSettingProvider;
+import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndexCreationException;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.InvalidIndexNameException;
 import org.opensearch.indices.ShardLimitValidator;
-import org.opensearch.indices.SystemIndexDescriptor;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.node.Node;
+import org.opensearch.node.remotestore.RemoteStoreNodeAttribute;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -103,6 +111,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiConsumer;
@@ -116,14 +125,24 @@
 import static java.util.stream.Collectors.toList;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING;
+import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_REPLICATION_TYPE_SETTING;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_CREATION_DATE;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_INDEX_UUID;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.cluster.metadata.Metadata.DEFAULT_REPLICA_COUNT_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreAttributePresent;
 
 /**
  * Service responsible for submitting create index requests
+ *
+ * @opensearch.internal
  */
 public class MetadataCreateIndexService {
     private static final Logger logger = LogManager.getLogger(MetadataCreateIndexService.class);
@@ -144,6 +163,8 @@ public class MetadataCreateIndexService {
     private final ShardLimitValidator shardLimitValidator;
     private final boolean forbidPrivateIndexSettings;
     private final Set<IndexSettingProvider> indexSettingProviders = new HashSet<>();
+    private final ClusterManagerTaskThrottler.ThrottlingKey createIndexTaskKey;
+    private AwarenessReplicaBalance awarenessReplicaBalance;
 
     public MetadataCreateIndexService(
         final Settings settings,
@@ -157,7 +178,8 @@ public MetadataCreateIndexService(
         final ThreadPool threadPool,
         final NamedXContentRegistry xContentRegistry,
         final SystemIndices systemIndices,
-        final boolean forbidPrivateIndexSettings
+        final boolean forbidPrivateIndexSettings,
+        final AwarenessReplicaBalance awarenessReplicaBalance
     ) {
         this.settings = settings;
         this.clusterService = clusterService;
@@ -171,6 +193,10 @@ public MetadataCreateIndexService(
         this.systemIndices = systemIndices;
         this.forbidPrivateIndexSettings = forbidPrivateIndexSettings;
         this.shardLimitValidator = shardLimitValidator;
+        this.awarenessReplicaBalance = awarenessReplicaBalance;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        createIndexTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_INDEX_KEY, true);
     }
 
     /**
@@ -214,17 +240,9 @@ public void validateIndexName(String index, ClusterState state) {
      * @param isHidden Whether or not this is a hidden index
      */
     public boolean validateDotIndex(String index, @Nullable Boolean isHidden) {
-        boolean isSystem = false;
         if (index.charAt(0) == '.') {
-            SystemIndexDescriptor matchingDescriptor = systemIndices.findMatchingDescriptor(index);
-            if (matchingDescriptor != null) {
-                logger.trace(
-                    "index [{}] is a system index because it matches index pattern [{}] with description [{}]",
-                    index,
-                    matchingDescriptor.getIndexPattern(),
-                    matchingDescriptor.getDescription()
-                );
-                isSystem = true;
+            if (systemIndices.validateSystemIndex(index)) {
+                return true;
             } else if (isHidden) {
                 logger.trace("index [{}] is a hidden index", index);
             } else {
@@ -237,14 +255,14 @@ public boolean validateDotIndex(String index, @Nullable Boolean isHidden) {
             }
         }
 
-        return isSystem;
+        return false;
     }
 
     /**
      * Validate the name for an index or alias against some static rules.
      */
     public static void validateIndexOrAliasName(String index, BiFunction<String, String, ? extends RuntimeException> exceptionCtor) {
-        if (!Strings.validFileName(index)) {
+        if (Strings.validFileName(index) == false) {
             throw exceptionCtor.apply(index, "must not contain the following characters " + Strings.INVALID_FILENAME_CHARS);
         }
         if (index.isEmpty()) {
@@ -328,6 +346,11 @@ protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                     return new ClusterStateUpdateResponse(acknowledged);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return createIndexTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) throws Exception {
                     return applyCreateIndexRequest(currentState, request, false);
@@ -546,7 +569,6 @@ private ClusterState applyCreateIndexRequestWithV1Templates(
                 xContentRegistry
             )
         );
-
         final Settings aggregatedIndexSettings = aggregateIndexSettings(
             currentState,
             request,
@@ -555,7 +577,8 @@ private ClusterState applyCreateIndexRequestWithV1Templates(
             settings,
             indexScopedSettings,
             shardLimitValidator,
-            indexSettingProviders
+            indexSettingProviders,
+            clusterService.getClusterSettings()
         );
         int routingNumShards = getIndexNumberOfRoutingShards(aggregatedIndexSettings, null);
         IndexMetadata tmpImd = buildAndValidateTemporaryIndexMetadata(currentState, aggregatedIndexSettings, request, routingNumShards);
@@ -619,7 +642,8 @@ private ClusterState applyCreateIndexRequestWithV2Template(
             settings,
             indexScopedSettings,
             shardLimitValidator,
-            indexSettingProviders
+            indexSettingProviders,
+            clusterService.getClusterSettings()
         );
         int routingNumShards = getIndexNumberOfRoutingShards(aggregatedIndexSettings, null);
         IndexMetadata tmpImd = buildAndValidateTemporaryIndexMetadata(currentState, aggregatedIndexSettings, request, routingNumShards);
@@ -699,7 +723,8 @@ private ClusterState applyCreateIndexRequestWithExistingMetadata(
             settings,
             indexScopedSettings,
             shardLimitValidator,
-            indexSettingProviders
+            indexSettingProviders,
+            clusterService.getClusterSettings()
         );
         final int routingNumShards = getIndexNumberOfRoutingShards(aggregatedIndexSettings, sourceMetadata);
         IndexMetadata tmpImd = buildAndValidateTemporaryIndexMetadata(currentState, aggregatedIndexSettings, request, routingNumShards);
@@ -722,7 +747,7 @@ private ClusterState applyCreateIndexRequestWithExistingMetadata(
                 // shard id and the current timestamp
                 indexService.newQueryShardContext(0, null, () -> 0L, null)
             ),
-            org.opensearch.common.collect.List.of(),
+            List.of(),
             metadataTransformer
         );
     }
@@ -782,7 +807,8 @@ static Settings aggregateIndexSettings(
         Settings settings,
         IndexScopedSettings indexScopedSettings,
         ShardLimitValidator shardLimitValidator,
-        Set<IndexSettingProvider> indexSettingProviders
+        Set<IndexSettingProvider> indexSettingProviders,
+        ClusterSettings clusterSettings
     ) {
         // Create builders for the template and request settings. We transform these into builders
         // because we may want settings to be "removed" from these prior to being set on the new
@@ -860,7 +886,7 @@ static Settings aggregateIndexSettings(
             indexSettingsBuilder.put(SETTING_NUMBER_OF_SHARDS, numberOfShards);
         }
         if (INDEX_NUMBER_OF_REPLICAS_SETTING.exists(indexSettingsBuilder) == false) {
-            indexSettingsBuilder.put(SETTING_NUMBER_OF_REPLICAS, INDEX_NUMBER_OF_REPLICAS_SETTING.get(settings));
+            indexSettingsBuilder.put(SETTING_NUMBER_OF_REPLICAS, DEFAULT_REPLICA_COUNT_SETTING.get(currentState.metadata().settings()));
         }
         if (settings.get(SETTING_AUTO_EXPAND_REPLICAS) != null && indexSettingsBuilder.get(SETTING_AUTO_EXPAND_REPLICAS) == null) {
             indexSettingsBuilder.put(SETTING_AUTO_EXPAND_REPLICAS, settings.get(SETTING_AUTO_EXPAND_REPLICAS));
@@ -872,6 +898,9 @@ static Settings aggregateIndexSettings(
         indexSettingsBuilder.put(IndexMetadata.SETTING_INDEX_PROVIDED_NAME, request.getProvidedName());
         indexSettingsBuilder.put(SETTING_INDEX_UUID, UUIDs.randomBase64UUID());
 
+        updateReplicationStrategy(indexSettingsBuilder, request.settings(), settings);
+        updateRemoteStoreSettings(indexSettingsBuilder, settings);
+
         if (sourceMetadata != null) {
             assert request.resizeType() != null;
             prepareResizeIndexSettings(
@@ -890,7 +919,7 @@ static Settings aggregateIndexSettings(
          * We can not validate settings until we have applied templates, otherwise we do not know the actual settings
          * that will be used to create this index.
          */
-        shardLimitValidator.validateShardLimit(indexSettings, currentState);
+        shardLimitValidator.validateShardLimit(request.index(), indexSettings, currentState);
         if (IndexSettings.INDEX_SOFT_DELETES_SETTING.get(indexSettings) == false
             && IndexMetadata.SETTING_INDEX_VERSION_CREATED.get(indexSettings).onOrAfter(Version.V_2_0_0)) {
             throw new IllegalArgumentException(
@@ -900,10 +929,54 @@ static Settings aggregateIndexSettings(
         }
         validateTranslogRetentionSettings(indexSettings);
         validateStoreTypeSettings(indexSettings);
+        validateRefreshIntervalSettings(request.settings(), clusterSettings);
+        validateTranslogDurabilitySettings(request.settings(), clusterSettings, settings);
 
         return indexSettings;
     }
 
+    /**
+     * Updates index settings to set replication strategy by default based on cluster level settings or remote store
+     * node attributes
+     * @param settingsBuilder index settings builder to be updated with relevant settings
+     * @param requestSettings settings passed in during index create request
+     * @param clusterSettings cluster level settings
+     */
+    private static void updateReplicationStrategy(Settings.Builder settingsBuilder, Settings requestSettings, Settings clusterSettings) {
+        if (INDEX_REPLICATION_TYPE_SETTING.exists(requestSettings)) {
+            settingsBuilder.put(SETTING_REPLICATION_TYPE, INDEX_REPLICATION_TYPE_SETTING.get(requestSettings));
+        } else if (CLUSTER_REPLICATION_TYPE_SETTING.exists(clusterSettings)) {
+            settingsBuilder.put(SETTING_REPLICATION_TYPE, CLUSTER_REPLICATION_TYPE_SETTING.get(clusterSettings));
+        } else if (isRemoteStoreAttributePresent(clusterSettings)) {
+            settingsBuilder.put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+        } else {
+            settingsBuilder.put(SETTING_REPLICATION_TYPE, CLUSTER_REPLICATION_TYPE_SETTING.getDefault(clusterSettings));
+        }
+    }
+
+    /**
+     * Updates index settings to enable remote store by default based on node attributes
+     * @param settingsBuilder index settings builder to be updated with relevant settings
+     * @param clusterSettings cluster level settings
+     */
+    private static void updateRemoteStoreSettings(Settings.Builder settingsBuilder, Settings clusterSettings) {
+        if (isRemoteStoreAttributePresent(clusterSettings)) {
+            settingsBuilder.put(SETTING_REMOTE_STORE_ENABLED, true)
+                .put(
+                    SETTING_REMOTE_SEGMENT_STORE_REPOSITORY,
+                    clusterSettings.get(
+                        Node.NODE_ATTRIBUTES.getKey() + RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY
+                    )
+                )
+                .put(
+                    SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY,
+                    clusterSettings.get(
+                        Node.NODE_ATTRIBUTES.getKey() + RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY
+                    )
+                );
+        }
+    }
+
     public static void validateStoreTypeSettings(Settings settings) {
         // deprecate simplefs store type:
         if (IndexModule.Type.SIMPLEFS.match(IndexModule.INDEX_STORE_TYPE_SETTING.get(settings))) {
@@ -1178,7 +1251,7 @@ private void validate(CreateIndexClusterStateUpdateRequest request, ClusterState
 
     public void validateIndexSettings(String indexName, final Settings settings, final boolean forbidPrivateIndexSettings)
         throws IndexCreationException {
-        List<String> validationErrors = getIndexSettingsValidationErrors(settings, forbidPrivateIndexSettings);
+        List<String> validationErrors = getIndexSettingsValidationErrors(settings, forbidPrivateIndexSettings, indexName);
 
         if (validationErrors.isEmpty() == false) {
             ValidationException validationException = new ValidationException();
@@ -1187,11 +1260,32 @@ public void validateIndexSettings(String indexName, final Settings settings, fin
         }
     }
 
-    List<String> getIndexSettingsValidationErrors(final Settings settings, final boolean forbidPrivateIndexSettings) {
+    List<String> getIndexSettingsValidationErrors(final Settings settings, final boolean forbidPrivateIndexSettings, String indexName) {
+        List<String> validationErrors = getIndexSettingsValidationErrors(settings, forbidPrivateIndexSettings, Optional.of(indexName));
+        return validationErrors;
+    }
+
+    List<String> getIndexSettingsValidationErrors(
+        final Settings settings,
+        final boolean forbidPrivateIndexSettings,
+        Optional<String> indexName
+    ) {
         List<String> validationErrors = validateIndexCustomPath(settings, env.sharedDataFile());
         if (forbidPrivateIndexSettings) {
             validationErrors.addAll(validatePrivateSettingsNotExplicitlySet(settings, indexScopedSettings));
         }
+        if (indexName.isEmpty() || indexName.get().charAt(0) != '.') {
+            // Apply aware replica balance validation only to non system indices
+            int replicaCount = settings.getAsInt(
+                IndexMetadata.SETTING_NUMBER_OF_REPLICAS,
+                DEFAULT_REPLICA_COUNT_SETTING.get(this.clusterService.state().metadata().settings())
+            );
+            AutoExpandReplicas autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+            Optional<String> error = awarenessReplicaBalance.validate(replicaCount, autoExpandReplica);
+            if (error.isPresent()) {
+                validationErrors.add(error.get());
+            }
+        }
         return validationErrors;
     }
 
@@ -1221,7 +1315,7 @@ private static List<String> validatePrivateSettingsNotExplicitlySet(Settings set
     private static List<String> validateIndexCustomPath(Settings settings, @Nullable Path sharedDataPath) {
         String customPath = IndexMetadata.INDEX_DATA_PATH_SETTING.get(settings);
         List<String> validationErrors = new ArrayList<>();
-        if (!Strings.isEmpty(customPath)) {
+        if (Strings.isEmpty(customPath) == false) {
             if (sharedDataPath == null) {
                 validationErrors.add("path.shared_data must be set in order to use custom data paths");
             } else {
@@ -1302,9 +1396,11 @@ static IndexMetadata validateResize(ClusterState state, String sourceIndex, Stri
             );
         }
 
-        // ensure index is read-only
+        // ensure write operations on the source index is blocked
         if (state.blocks().indexBlocked(ClusterBlockLevel.WRITE, sourceIndex) == false) {
-            throw new IllegalStateException("index " + sourceIndex + " must be read-only to resize index. use \"index.blocks.write=true\"");
+            throw new IllegalStateException(
+                "index " + sourceIndex + " must block write operations to resize index. use \"index.blocks.write=true\""
+            );
         }
 
         if (IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.exists(targetIndexSettings)) {
@@ -1419,4 +1515,50 @@ public static void validateTranslogRetentionSettings(Settings indexSettings) {
             }
         }
     }
+
+    /**
+     * Validates {@code index.refresh_interval} is equal or below the {@code cluster.minimum.index.refresh_interval}.
+     *
+     * @param requestSettings settings passed in during index create/update request
+     * @param clusterSettings cluster setting
+     */
+    static void validateRefreshIntervalSettings(Settings requestSettings, ClusterSettings clusterSettings) {
+        if (IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.exists(requestSettings) == false) {
+            return;
+        }
+        TimeValue requestRefreshInterval = IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.get(requestSettings);
+        TimeValue clusterMinimumRefreshInterval = clusterSettings.get(IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING);
+        if (requestRefreshInterval.millis() < clusterMinimumRefreshInterval.millis()) {
+            throw new IllegalArgumentException(
+                "invalid index.refresh_interval ["
+                    + requestRefreshInterval
+                    + "]: cannot be smaller than cluster.minimum.index.refresh_interval ["
+                    + clusterMinimumRefreshInterval
+                    + "]"
+            );
+        }
+    }
+
+    /**
+     * Validates {@code index.translog.durability} is not async if the {@code cluster.remote_store.index.restrict.async-durability} is set to true.
+     *
+     * @param requestSettings settings passed in during index create/update request
+     * @param clusterSettings cluster setting
+     */
+    static void validateTranslogDurabilitySettings(Settings requestSettings, ClusterSettings clusterSettings, Settings settings) {
+        if (isRemoteStoreAttributePresent(settings) == false
+            || IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.exists(requestSettings) == false
+            || clusterSettings.get(IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING) == false) {
+            return;
+        }
+        Translog.Durability durability = IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.get(requestSettings);
+        if (durability.equals(Translog.Durability.ASYNC)) {
+            throw new IllegalArgumentException(
+                "index setting [index.translog.durability=async] is not allowed as cluster setting ["
+                    + IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey()
+                    + "=true]"
+            );
+        }
+
+    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataDeleteIndexService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataDeleteIndexService.java
index 4805cb215fc09..5352a8a3fb994 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataDeleteIndexService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataDeleteIndexService.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.delete.DeleteIndexClusterStateUpdateRequest;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
@@ -43,18 +42,21 @@
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
 import org.opensearch.snapshots.RestoreService;
 import org.opensearch.snapshots.SnapshotInProgressException;
 import org.opensearch.snapshots.SnapshotsService;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -62,6 +64,8 @@
 
 /**
  * Deletes indices.
+ *
+ * @opensearch.internal
  */
 public class MetadataDeleteIndexService {
 
@@ -71,12 +75,17 @@ public class MetadataDeleteIndexService {
     private final ClusterService clusterService;
 
     private final AllocationService allocationService;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deleteIndexTaskKey;
 
     @Inject
     public MetadataDeleteIndexService(Settings settings, ClusterService clusterService, AllocationService allocationService) {
         this.settings = settings;
         this.clusterService = clusterService;
         this.allocationService = allocationService;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        deleteIndexTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_INDEX_KEY, true);
+
     }
 
     public void deleteIndices(
@@ -96,6 +105,11 @@ protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                     return new ClusterStateUpdateResponse(acknowledged);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return deleteIndexTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(final ClusterState currentState) {
                     return deleteIndices(currentState, Sets.newHashSet(request.indices()));
@@ -171,13 +185,13 @@ public ClusterState deleteIndices(ClusterState currentState, Set<Index> indices)
         ClusterBlocks blocks = clusterBlocksBuilder.build();
 
         // update snapshot restore entries
-        ImmutableOpenMap<String, ClusterState.Custom> customs = currentState.getCustoms();
+        Map<String, ClusterState.Custom> customs = currentState.getCustoms();
         final RestoreInProgress restoreInProgress = currentState.custom(RestoreInProgress.TYPE, RestoreInProgress.EMPTY);
         RestoreInProgress updatedRestoreInProgress = RestoreService.updateRestoreStateWithDeletedIndices(restoreInProgress, indices);
         if (updatedRestoreInProgress != restoreInProgress) {
-            ImmutableOpenMap.Builder<String, ClusterState.Custom> builder = ImmutableOpenMap.builder(customs);
+            final Map<String, ClusterState.Custom> builder = new HashMap<>(customs);
             builder.put(RestoreInProgress.TYPE, updatedRestoreInProgress);
-            customs = builder.build();
+            customs = Collections.unmodifiableMap(builder);
         }
 
         return allocationService.reroute(
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexAliasesService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexAliasesService.java
index a490bae65ca00..96ba3d60ce9a6 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexAliasesService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexAliasesService.java
@@ -33,18 +33,20 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesClusterStateUpdateRequest;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.metadata.AliasAction.NewAliasValidator;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperService;
@@ -64,6 +66,8 @@
 
 /**
  * Service responsible for submitting add and remove aliases requests
+ *
+ * @opensearch.internal
  */
 public class MetadataIndexAliasesService {
 
@@ -76,6 +80,7 @@ public class MetadataIndexAliasesService {
     private final MetadataDeleteIndexService deleteIndexService;
 
     private final NamedXContentRegistry xContentRegistry;
+    private final ClusterManagerTaskThrottler.ThrottlingKey indexAliasTaskKey;
 
     @Inject
     public MetadataIndexAliasesService(
@@ -90,6 +95,10 @@ public MetadataIndexAliasesService(
         this.aliasValidator = aliasValidator;
         this.deleteIndexService = deleteIndexService;
         this.xContentRegistry = xContentRegistry;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        indexAliasTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.INDEX_ALIASES_KEY, true);
+
     }
 
     public void indicesAliases(
@@ -104,6 +113,11 @@ protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                     return new ClusterStateUpdateResponse(acknowledged);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return indexAliasTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) {
                     return applyAliasActions(currentState, request.actions());
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexStateService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexStateService.java
index 25071a60bdfb5..dc98b60484b20 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexStateService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexStateService.java
@@ -32,16 +32,13 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
-import org.opensearch.action.NotifyOnceListener;
 import org.opensearch.action.admin.indices.close.CloseIndexClusterStateUpdateRequest;
 import org.opensearch.action.admin.indices.close.CloseIndexResponse;
 import org.opensearch.action.admin.indices.close.CloseIndexResponse.IndexResult;
@@ -70,9 +67,7 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.Setting;
@@ -81,16 +76,19 @@
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.snapshots.RestoreService;
 import org.opensearch.snapshots.SnapshotInProgressException;
 import org.opensearch.snapshots.SnapshotsService;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.ArrayList;
@@ -112,6 +110,8 @@
 
 /**
  * Service responsible for submitting open/close index requests as well as for adding index blocks
+ *
+ * @opensearch.internal
  */
 public class MetadataIndexStateService {
     private static final Logger logger = LogManager.getLogger(MetadataIndexStateService.class);
@@ -581,6 +581,8 @@ public TimeValue timeout() {
      * This step iterates over the indices previously blocked and sends a {@link TransportVerifyShardBeforeCloseAction} to each shard. If
      * this action succeed then the shard is considered to be ready for closing. When all shards of a given index are ready for closing,
      * the index is considered ready to be closed.
+     *
+     * @opensearch.internal
      */
     class WaitForClosedBlocksApplied extends ActionRunnable<Map<Index, IndexResult>> {
 
@@ -635,12 +637,12 @@ private void waitForShardsReadyForClosing(
                 return;
             }
 
-            final ImmutableOpenIntMap<IndexShardRoutingTable> shards = indexRoutingTable.getShards();
+            final Map<Integer, IndexShardRoutingTable> shards = indexRoutingTable.getShards();
             final AtomicArray<ShardResult> results = new AtomicArray<>(shards.size());
             final CountDown countDown = new CountDown(shards.size());
 
-            for (IntObjectCursor<IndexShardRoutingTable> shard : shards) {
-                final IndexShardRoutingTable shardRoutingTable = shard.value;
+            for (final IndexShardRoutingTable shard : shards.values()) {
+                final IndexShardRoutingTable shardRoutingTable = shard;
                 final int shardId = shardRoutingTable.shardId().id();
                 sendVerifyShardBeforeCloseRequest(shardRoutingTable, closingBlock, new NotifyOnceListener<ReplicationResponse>() {
                     @Override
@@ -713,6 +715,8 @@ public void onFailure(Exception e) {
     /**
      * Helper class that coordinates with shards to ensure that blocks have been properly applied to all shards using
      * {@link TransportVerifyShardIndexBlockAction}.
+     *
+     * @opensearch.metadata
      */
     class WaitForBlocksApplied extends ActionRunnable<Map<Index, AddBlockResult>> {
 
@@ -766,12 +770,12 @@ private void waitForShardsReady(
                 return;
             }
 
-            final ImmutableOpenIntMap<IndexShardRoutingTable> shards = indexRoutingTable.getShards();
+            final Map<Integer, IndexShardRoutingTable> shards = indexRoutingTable.getShards();
             final AtomicArray<AddBlockShardResult> results = new AtomicArray<>(shards.size());
             final CountDown countDown = new CountDown(shards.size());
 
-            for (IntObjectCursor<IndexShardRoutingTable> shard : shards) {
-                final IndexShardRoutingTable shardRoutingTable = shard.value;
+            for (final IndexShardRoutingTable shard : shards.values()) {
+                final IndexShardRoutingTable shardRoutingTable = shard;
                 final int shardId = shardRoutingTable.shardId().id();
                 sendVerifyShardBlockRequest(shardRoutingTable, clusterBlock, new NotifyOnceListener<ReplicationResponse>() {
                     @Override
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexTemplateService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexTemplateService.java
index 896679206aec5..71b86ec853ce4 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexTemplateService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexTemplateService.java
@@ -31,27 +31,24 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.CollectionUtil;
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.Operations;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.Alias;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
-import org.opensearch.action.support.master.MasterNodeRequest;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.ValidationException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.logging.HeaderWarning;
@@ -60,11 +57,14 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.mapper.MapperService;
@@ -97,6 +97,8 @@
 
 /**
  * Service responsible for submitting index templates updates
+ *
+ * @opensearch.internal
  */
 public class MetadataIndexTemplateService {
 
@@ -107,6 +109,12 @@ public class MetadataIndexTemplateService {
     private final MetadataCreateIndexService metadataCreateIndexService;
     private final IndexScopedSettings indexScopedSettings;
     private final NamedXContentRegistry xContentRegistry;
+    private final ClusterManagerTaskThrottler.ThrottlingKey createIndexTemplateTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey createIndexTemplateV2TaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey removeIndexTemplateTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey removeIndexTemplateV2TaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey createComponentTemplateTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey removeComponentTemplateTaskKey;
 
     @Inject
     public MetadataIndexTemplateService(
@@ -123,6 +131,20 @@ public MetadataIndexTemplateService(
         this.metadataCreateIndexService = metadataCreateIndexService;
         this.indexScopedSettings = indexScopedSettings;
         this.xContentRegistry = xContentRegistry;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        createIndexTemplateTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_INDEX_TEMPLATE_KEY, true);
+        createIndexTemplateV2TaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_INDEX_TEMPLATE_V2_KEY, true);
+        removeIndexTemplateTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.REMOVE_INDEX_TEMPLATE_KEY, true);
+        removeIndexTemplateV2TaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.REMOVE_INDEX_TEMPLATE_V2_KEY, true);
+        createComponentTemplateTaskKey = clusterService.registerClusterManagerTask(
+            ClusterManagerTaskKeys.CREATE_COMPONENT_TEMPLATE_KEY,
+            true
+        );
+        removeComponentTemplateTaskKey = clusterService.registerClusterManagerTask(
+            ClusterManagerTaskKeys.REMOVE_COMPONENT_TEMPLATE_KEY,
+            true
+        );
     }
 
     public void removeTemplates(final RemoveRequest request, final RemoveListener listener) {
@@ -130,7 +152,7 @@ public void removeTemplates(final RemoveRequest request, final RemoveListener li
 
             @Override
             public TimeValue timeout() {
-                return request.masterTimeout;
+                return request.clusterManagerTimeout;
             }
 
             @Override
@@ -138,11 +160,15 @@ public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return removeIndexTemplateTaskKey;
+            }
+
             @Override
             public ClusterState execute(ClusterState currentState) {
                 Set<String> templateNames = new HashSet<>();
-                for (ObjectCursor<String> cursor : currentState.metadata().templates().keys()) {
-                    String templateName = cursor.value;
+                for (final String templateName : currentState.metadata().templates().keySet()) {
                     if (Regex.simpleMatch(request.name, templateName)) {
                         templateNames.add(templateName);
                     }
@@ -196,6 +222,11 @@ public void onFailure(String source, Exception e) {
                     listener.onFailure(e);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return createComponentTemplateTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) throws Exception {
                     return addComponentTemplate(currentState, create, name, template);
@@ -271,9 +302,11 @@ ClusterState addComponentTemplate(
         if (stringMappings != null) {
             Map<String, Object> parsedMappings = MapperService.parseMapping(xContentRegistry, stringMappings);
             if (parsedMappings.size() > 0) {
-                stringMappings = Strings.toString(
-                    XContentFactory.jsonBuilder().startObject().field(MapperService.SINGLE_MAPPING_NAME, parsedMappings).endObject()
-                );
+                stringMappings = XContentFactory.jsonBuilder()
+                    .startObject()
+                    .field(MapperService.SINGLE_MAPPING_NAME, parsedMappings)
+                    .endObject()
+                    .toString();
             }
         }
 
@@ -356,6 +389,11 @@ public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return removeComponentTemplateTaskKey;
+            }
+
             @Override
             public ClusterState execute(ClusterState currentState) {
                 Set<String> templateNames = new HashSet<>();
@@ -445,6 +483,11 @@ public void onFailure(String source, Exception e) {
                     listener.onFailure(e);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return createIndexTemplateV2TaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) throws Exception {
                     return addIndexTemplateV2(currentState, create, name, template);
@@ -550,9 +593,11 @@ public ClusterState addIndexTemplateV2(
             if (stringMappings != null) {
                 Map<String, Object> parsedMappings = MapperService.parseMapping(xContentRegistry, stringMappings);
                 if (parsedMappings.size() > 0) {
-                    stringMappings = Strings.toString(
-                        XContentFactory.jsonBuilder().startObject().field(MapperService.SINGLE_MAPPING_NAME, parsedMappings).endObject()
-                    );
+                    stringMappings = XContentFactory.jsonBuilder()
+                        .startObject()
+                        .field(MapperService.SINGLE_MAPPING_NAME, parsedMappings)
+                        .endObject()
+                        .toString();
                 }
             }
             final Template finalTemplate = new Template(
@@ -669,9 +714,9 @@ public static Map<String, List<String>> findConflictingV1Templates(
     ) {
         Automaton v2automaton = Regex.simpleMatchToAutomaton(indexPatterns.toArray(Strings.EMPTY_ARRAY));
         Map<String, List<String>> overlappingTemplates = new HashMap<>();
-        for (ObjectObjectCursor<String, IndexTemplateMetadata> cursor : state.metadata().templates()) {
-            String name = cursor.key;
-            IndexTemplateMetadata template = cursor.value;
+        for (final Map.Entry<String, IndexTemplateMetadata> cursor : state.metadata().templates().entrySet()) {
+            String name = cursor.getKey();
+            IndexTemplateMetadata template = cursor.getValue();
             Automaton v1automaton = Regex.simpleMatchToAutomaton(template.patterns().toArray(Strings.EMPTY_ARRAY));
             if (Operations.isEmpty(Operations.intersection(v2automaton, v1automaton)) == false) {
                 logger.debug(
@@ -762,6 +807,11 @@ public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return removeIndexTemplateV2TaskKey;
+            }
+
             @Override
             public ClusterState execute(ClusterState currentState) {
                 return innerRemoveIndexTemplateV2(currentState, name);
@@ -858,7 +908,7 @@ public void putTemplate(final PutRequest request, final PutListener listener) {
 
                 @Override
                 public TimeValue timeout() {
-                    return request.masterTimeout;
+                    return request.clusterManagerTimeout;
                 }
 
                 @Override
@@ -866,6 +916,11 @@ public void onFailure(String source, Exception e) {
                     listener.onFailure(e);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return createIndexTemplateTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) throws Exception {
                     validateTemplate(request.settings, request.mappings, indicesService, xContentRegistry);
@@ -960,8 +1015,7 @@ static ClusterState innerPutTemplate(
     public static List<IndexTemplateMetadata> findV1Templates(Metadata metadata, String indexName, @Nullable Boolean isHidden) {
         final Predicate<String> patternMatchPredicate = pattern -> Regex.simpleMatch(pattern, indexName);
         final List<IndexTemplateMetadata> matchedTemplates = new ArrayList<>();
-        for (ObjectCursor<IndexTemplateMetadata> cursor : metadata.templates().values()) {
-            final IndexTemplateMetadata template = cursor.value;
+        for (final IndexTemplateMetadata template : metadata.templates().values()) {
             if (isHidden == null || isHidden == Boolean.FALSE) {
                 final boolean matched = template.patterns().stream().anyMatch(patternMatchPredicate);
                 if (matched) {
@@ -1101,7 +1155,7 @@ public static List<CompressedXContent> collectMappings(final ClusterState state,
             Optional.ofNullable(template.getDataStreamTemplate())
                 .map(ComposableIndexTemplate.DataStreamTemplate::getDataStreamMappingSnippet)
                 .map(mapping -> {
-                    try (XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent())) {
+                    try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
                         builder.value(mapping);
                         return new CompressedXContent(BytesReference.bytes(builder));
                     } catch (IOException e) {
@@ -1184,8 +1238,8 @@ public static List<Map<String, AliasMetadata>> resolveAliases(final List<IndexTe
         templates.forEach(template -> {
             if (template.aliases() != null) {
                 Map<String, AliasMetadata> aliasMeta = new HashMap<>();
-                for (ObjectObjectCursor<String, AliasMetadata> cursor : template.aliases()) {
-                    aliasMeta.put(cursor.key, cursor.value);
+                for (final Map.Entry<String, AliasMetadata> cursor : template.aliases().entrySet()) {
+                    aliasMeta.put(cursor.getKey(), cursor.getValue());
                 }
                 resolvedAliases.add(aliasMeta);
             }
@@ -1469,7 +1523,11 @@ private void validate(String name, @Nullable Settings settings, List<String> ind
                     validationErrors.add(t.getMessage());
                 }
             }
-            List<String> indexSettingsValidation = metadataCreateIndexService.getIndexSettingsValidationErrors(settings, true);
+            List<String> indexSettingsValidation = metadataCreateIndexService.getIndexSettingsValidationErrors(
+                settings,
+                true,
+                Optional.empty()
+            );
             validationErrors.addAll(indexSettingsValidation);
         }
 
@@ -1496,6 +1554,11 @@ private void validate(String name, @Nullable Settings settings, List<String> ind
         }
     }
 
+    /**
+     * Listener for putting metadata in the template
+     *
+     * @opensearch.internal
+     */
     public interface PutListener {
 
         void onResponse(PutResponse response);
@@ -1503,6 +1566,11 @@ public interface PutListener {
         void onFailure(Exception e);
     }
 
+    /**
+     * A PUT request.
+     *
+     * @opensearch.internal
+     */
     public static class PutRequest {
         final String name;
         final String cause;
@@ -1514,7 +1582,11 @@ public static class PutRequest {
         String mappings = null;
         List<Alias> aliases = new ArrayList<>();
 
-        TimeValue masterTimeout = MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+        TimeValue clusterManagerTimeout = ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
+
+        /** @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerTimeout} */
+        @Deprecated
+        TimeValue masterTimeout = ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
 
         public PutRequest(String cause, String name) {
             this.cause = cause;
@@ -1551,17 +1623,28 @@ public PutRequest aliases(Set<Alias> aliases) {
             return this;
         }
 
-        public PutRequest masterTimeout(TimeValue masterTimeout) {
-            this.masterTimeout = masterTimeout;
+        public PutRequest clusterManagerTimeout(TimeValue clusterManagerTimeout) {
+            this.clusterManagerTimeout = clusterManagerTimeout;
             return this;
         }
 
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerTimeout(TimeValue)} */
+        @Deprecated
+        public PutRequest masterTimeout(TimeValue masterTimeout) {
+            return clusterManagerTimeout(masterTimeout);
+        }
+
         public PutRequest version(Integer version) {
             this.version = version;
             return this;
         }
     }
 
+    /**
+     * The PUT response.
+     *
+     * @opensearch.internal
+     */
     public static class PutResponse {
         private final boolean acknowledged;
 
@@ -1574,20 +1657,40 @@ public boolean acknowledged() {
         }
     }
 
+    /**
+     * A remove Request.
+     *
+     * @opensearch.internal
+     */
     public static class RemoveRequest {
         final String name;
-        TimeValue masterTimeout = MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+        TimeValue clusterManagerTimeout = ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
+
+        /** @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #clusterManagerTimeout} */
+        @Deprecated
+        TimeValue masterTimeout = ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
 
         public RemoveRequest(String name) {
             this.name = name;
         }
 
-        public RemoveRequest masterTimeout(TimeValue masterTimeout) {
-            this.masterTimeout = masterTimeout;
+        public RemoveRequest clusterManagerTimeout(TimeValue clusterManagerTimeout) {
+            this.clusterManagerTimeout = clusterManagerTimeout;
             return this;
         }
+
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerTimeout} */
+        @Deprecated
+        public RemoveRequest masterTimeout(TimeValue masterTimeout) {
+            return clusterManagerTimeout(masterTimeout);
+        }
     }
 
+    /**
+     * A remove Response.
+     *
+     * @opensearch.internal
+     */
     public static class RemoveResponse {
         private final boolean acknowledged;
 
@@ -1600,6 +1703,11 @@ public boolean acknowledged() {
         }
     }
 
+    /**
+     * A remove listener.
+     *
+     * @opensearch.internal
+     */
     public interface RemoveListener {
 
         void onResponse(RemoveResponse response);
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeService.java
index f6f42e0d81063..54797dfa0c22c 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeService.java
@@ -37,11 +37,12 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.search.similarities.BM25Similarity;
 import org.apache.lucene.search.similarities.Similarity;
+import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -64,6 +65,8 @@
  * to upgrade the existing index metadata to the latest version of the cluster. It typically
  * occurs during cluster upgrade, when dangling indices are imported into the cluster or indices
  * are restored from a repository.
+ *
+ * @opensearch.internal
  */
 public class MetadataIndexUpgradeService {
 
@@ -93,7 +96,7 @@ public MetadataIndexUpgradeService(
     }
 
     /**
-     * Checks that the index can be upgraded to the current version of the master node.
+     * Checks that the index can be upgraded to the current version of the cluster-manager node.
      *
      * <p>
      * If the index does not need upgrade it returns the index metadata unchanged, otherwise it returns a modified index metadata. If index
@@ -134,20 +137,35 @@ boolean isUpgraded(IndexMetadata indexMetadata) {
     private void checkSupportedVersion(IndexMetadata indexMetadata, Version minimumIndexCompatibilityVersion) {
         if (indexMetadata.getState() == IndexMetadata.State.OPEN
             && isSupportedVersion(indexMetadata, minimumIndexCompatibilityVersion) == false) {
-            throw new IllegalStateException(
-                "The index ["
-                    + indexMetadata.getIndex()
-                    + "] was created with version ["
-                    + indexMetadata.getCreationVersion()
-                    + "] but the minimum compatible version is ["
-
-                    + minimumIndexCompatibilityVersion
-                    + "]. It should be re-indexed in OpenSearch "
-                    + minimumIndexCompatibilityVersion.major
-                    + ".x before upgrading to "
-                    + Version.CURRENT
-                    + "."
-            );
+            if (minimumIndexCompatibilityVersion.equals(LegacyESVersion.V_7_0_0)) {
+                // This branch can be removed when LegacyESVersion is removed
+                throw new IllegalStateException(
+                    "The index ["
+                        + indexMetadata.getIndex()
+                        + "] was created with version ["
+                        + indexMetadata.getCreationVersion()
+                        + "] but the minimum compatible version is "
+                        + "OpenSearch 1.0.0 (or Elasticsearch 7.0.0). "
+                        + "It should be re-indexed in OpenSearch 1.x "
+                        + "(or Elasticsearch 7.x) before upgrading to "
+                        + Version.CURRENT
+                        + "."
+                );
+            } else {
+                throw new IllegalStateException(
+                    "The index ["
+                        + indexMetadata.getIndex()
+                        + "] was created with version ["
+                        + indexMetadata.getCreationVersion()
+                        + "] but the minimum compatible version is ["
+                        + minimumIndexCompatibilityVersion
+                        + "]. It should be re-indexed in OpenSearch "
+                        + minimumIndexCompatibilityVersion.major
+                        + ".x before upgrading to "
+                        + Version.CURRENT
+                        + "."
+                );
+            }
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataMappingService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataMappingService.java
index 3795961d39143..1406287149e8d 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataMappingService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataMappingService.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingClusterStateUpdateRequest;
 import org.opensearch.cluster.AckedClusterStateTaskListener;
 import org.opensearch.cluster.ClusterState;
@@ -43,15 +42,18 @@
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MapperService;
@@ -69,6 +71,8 @@
 
 /**
  * Service responsible for submitting mapping changes
+ *
+ * @opensearch.internal
  */
 public class MetadataMappingService {
 
@@ -76,6 +80,7 @@ public class MetadataMappingService {
 
     private final ClusterService clusterService;
     private final IndicesService indicesService;
+    private final ClusterManagerTaskThrottler.ThrottlingKey putMappingTaskKey;
 
     final RefreshTaskExecutor refreshExecutor = new RefreshTaskExecutor();
     final PutMappingExecutor putMappingExecutor = new PutMappingExecutor();
@@ -84,6 +89,10 @@ public class MetadataMappingService {
     public MetadataMappingService(ClusterService clusterService, IndicesService indicesService) {
         this.clusterService = clusterService;
         this.indicesService = indicesService;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        putMappingTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.PUT_MAPPING_KEY, true);
+
     }
 
     static class RefreshTask {
@@ -244,6 +253,11 @@ public ClusterTasksResult<PutMappingClusterStateUpdateRequest> execute(
             }
         }
 
+        @Override
+        public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+            return putMappingTaskKey;
+        }
+
         private ClusterState applyRequest(
             ClusterState currentState,
             PutMappingClusterStateUpdateRequest request,
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/MetadataUpdateSettingsService.java b/server/src/main/java/org/opensearch/cluster/metadata/MetadataUpdateSettingsService.java
index 1b7aee48e3232..7d4c3512ed757 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/MetadataUpdateSettingsService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/MetadataUpdateSettingsService.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsClusterStateUpdateRequest;
 import org.opensearch.action.admin.indices.upgrade.post.UpgradeSettingsClusterStateUpdateRequest;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
@@ -46,6 +45,9 @@
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.ValidationException;
@@ -55,7 +57,8 @@
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
@@ -70,10 +73,15 @@
 import java.util.Set;
 
 import static org.opensearch.action.support.ContextPreservingActionListener.wrapPreservingContext;
+import static org.opensearch.cluster.metadata.MetadataCreateIndexService.validateRefreshIntervalSettings;
+import static org.opensearch.cluster.metadata.MetadataCreateIndexService.validateTranslogDurabilitySettings;
+import static org.opensearch.common.settings.AbstractScopedSettings.ARCHIVED_SETTINGS_PREFIX;
 import static org.opensearch.index.IndexSettings.same;
 
 /**
  * Service responsible for submitting update index settings requests
+ *
+ * @opensearch.internal
  */
 public class MetadataUpdateSettingsService {
     private static final Logger logger = LogManager.getLogger(MetadataUpdateSettingsService.class);
@@ -86,6 +94,9 @@ public class MetadataUpdateSettingsService {
     private final IndicesService indicesService;
     private final ShardLimitValidator shardLimitValidator;
     private final ThreadPool threadPool;
+    private final ClusterManagerTaskThrottler.ThrottlingKey updateSettingsTaskKey;
+
+    private AwarenessReplicaBalance awarenessReplicaBalance;
 
     @Inject
     public MetadataUpdateSettingsService(
@@ -94,7 +105,8 @@ public MetadataUpdateSettingsService(
         IndexScopedSettings indexScopedSettings,
         IndicesService indicesService,
         ShardLimitValidator shardLimitValidator,
-        ThreadPool threadPool
+        ThreadPool threadPool,
+        AwarenessReplicaBalance awarenessReplicaBalance
     ) {
         this.clusterService = clusterService;
         this.threadPool = threadPool;
@@ -102,6 +114,10 @@ public MetadataUpdateSettingsService(
         this.indexScopedSettings = indexScopedSettings;
         this.indicesService = indicesService;
         this.shardLimitValidator = shardLimitValidator;
+        this.awarenessReplicaBalance = awarenessReplicaBalance;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        updateSettingsTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.UPDATE_SETTINGS_KEY, true);
     }
 
     public void updateSettings(
@@ -112,6 +128,10 @@ public void updateSettings(
             .put(request.settings())
             .normalizePrefix(IndexMetadata.INDEX_SETTING_PREFIX)
             .build();
+
+        validateRefreshIntervalSettings(normalizedSettings, clusterService.getClusterSettings());
+        validateTranslogDurabilitySettings(normalizedSettings, clusterService.getClusterSettings(), clusterService.getSettings());
+
         Settings.Builder settingsForClosedIndices = Settings.builder();
         Settings.Builder settingsForOpenIndices = Settings.builder();
         final Set<String> skippedSettings = new HashSet<>();
@@ -119,12 +139,16 @@ public void updateSettings(
         indexScopedSettings.validate(
             normalizedSettings.filter(s -> Regex.isSimpleMatchPattern(s) == false), // don't validate wildcards
             false, // don't validate dependencies here we check it below never allow to change the number of shards
+            false,
+            true, // Ignore archived setting.
             true
         ); // validate internal or private index settings
         for (String key : normalizedSettings.keySet()) {
             Setting setting = indexScopedSettings.get(key);
             boolean isWildcard = setting == null && Regex.isSimpleMatchPattern(key);
+            boolean isArchived = key.startsWith(ARCHIVED_SETTINGS_PREFIX);
             assert setting != null // we already validated the normalized settings
+                || isArchived
                 || (isWildcard && normalizedSettings.hasValue(key) == false) : "unknown setting: "
                     + key
                     + " isWildcard: "
@@ -132,7 +156,8 @@ public void updateSettings(
                     + " hasValue: "
                     + normalizedSettings.hasValue(key);
             settingsForClosedIndices.copy(key, normalizedSettings);
-            if (isWildcard || setting.isDynamic()) {
+            // Only allow dynamic settings and wildcards for open indices. Skip archived settings.
+            if (isArchived == false && (isWildcard || setting.isDynamic())) {
                 settingsForOpenIndices.copy(key, normalizedSettings);
             } else {
                 skippedSettings.add(key);
@@ -155,6 +180,11 @@ protected ClusterStateUpdateResponse newResponse(boolean acknowledged) {
                     return new ClusterStateUpdateResponse(acknowledged);
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return updateSettingsTaskKey;
+                }
+
                 @Override
                 public ClusterState execute(ClusterState currentState) {
 
@@ -191,6 +221,22 @@ public ClusterState execute(ClusterState currentState) {
                     if (IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.exists(openSettings)) {
                         final int updatedNumberOfReplicas = IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.get(openSettings);
                         if (preserveExisting == false) {
+                            for (Index index : request.indices()) {
+                                if (index.getName().charAt(0) != '.') {
+                                    // No replica count validation for system indices
+                                    Optional<String> error = awarenessReplicaBalance.validate(
+                                        updatedNumberOfReplicas,
+                                        AutoExpandReplicas.SETTING.get(openSettings)
+                                    );
+
+                                    if (error.isPresent()) {
+                                        ValidationException ex = new ValidationException();
+                                        ex.addValidationError(error.get());
+                                        throw ex;
+                                    }
+                                }
+                            }
+
                             // Verify that this won't take us over the cluster shard limit.
                             int totalNewShards = Arrays.stream(request.indices())
                                 .mapToInt(i -> getTotalNewShards(i, currentState, updatedNumberOfReplicas))
@@ -271,6 +317,8 @@ public ClusterState execute(ClusterState currentState) {
                                 Settings finalSettings = indexSettings.build();
                                 indexScopedSettings.validate(
                                     finalSettings.filter(k -> indexScopedSettings.isPrivateSetting(k) == false),
+                                    true,
+                                    false,
                                     true
                                 );
                                 metadataBuilder.put(IndexMetadata.builder(indexMetadata).settings(finalSettings));
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/ProcessClusterEventTimeoutException.java b/server/src/main/java/org/opensearch/cluster/metadata/ProcessClusterEventTimeoutException.java
index 079c4c680e42d..8f2b9c3bbd36a 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/ProcessClusterEventTimeoutException.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/ProcessClusterEventTimeoutException.java
@@ -33,12 +33,17 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when there is a timeout processing cluster events
+ *
+ * @opensearch.internal
+ */
 public class ProcessClusterEventTimeoutException extends OpenSearchException {
 
     public ProcessClusterEventTimeoutException(TimeValue timeValue, String source) {
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/RepositoriesMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/RepositoriesMetadata.java
index 3076ede7ced14..a5ef337c3b62a 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/RepositoriesMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/RepositoriesMetadata.java
@@ -38,13 +38,14 @@
 import org.opensearch.cluster.NamedDiff;
 import org.opensearch.cluster.metadata.Metadata.Custom;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.repositories.RepositoryData;
 
 import java.io.IOException;
@@ -53,8 +54,12 @@
 import java.util.EnumSet;
 import java.util.List;
 
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.SYSTEM_REPOSITORY_SETTING;
+
 /**
  * Contains metadata about registered snapshot repositories
+ *
+ * @opensearch.internal
  */
 public class RepositoriesMetadata extends AbstractNamedDiffable<Custom> implements Custom {
 
@@ -205,6 +210,7 @@ public static RepositoriesMetadata fromXContent(XContentParser parser) throws IO
                 Settings settings = Settings.EMPTY;
                 long generation = RepositoryData.UNKNOWN_REPO_GEN;
                 long pendingGeneration = RepositoryData.EMPTY_REPO_GEN;
+                CryptoMetadata cryptoMetadata = null;
                 while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                     if (token == XContentParser.Token.FIELD_NAME) {
                         String currentFieldName = parser.currentName();
@@ -228,6 +234,11 @@ public static RepositoriesMetadata fromXContent(XContentParser parser) throws IO
                                 throw new OpenSearchParseException("failed to parse repository [{}], unknown type", name);
                             }
                             pendingGeneration = parser.longValue();
+                        } else if (CryptoMetadata.CRYPTO_METADATA_KEY.equals(currentFieldName)) {
+                            if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                                throw new OpenSearchParseException("failed to parse repository [{}], unknown type", name);
+                            }
+                            cryptoMetadata = CryptoMetadata.fromXContent(parser);
                         } else {
                             throw new OpenSearchParseException(
                                 "failed to parse repository [{}], unknown field [{}]",
@@ -242,7 +253,7 @@ public static RepositoriesMetadata fromXContent(XContentParser parser) throws IO
                 if (type == null) {
                     throw new OpenSearchParseException("failed to parse repository [{}], missing repository type", name);
                 }
-                repository.add(new RepositoryMetadata(name, type, settings, generation, pendingGeneration));
+                repository.add(new RepositoryMetadata(name, type, settings, generation, pendingGeneration, cryptoMetadata));
             } else {
                 throw new OpenSearchParseException("failed to parse repositories");
             }
@@ -276,8 +287,15 @@ public EnumSet<Metadata.XContentContext> context() {
     public static void toXContent(RepositoryMetadata repository, XContentBuilder builder, ToXContent.Params params) throws IOException {
         builder.startObject(repository.name());
         builder.field("type", repository.type());
+        if (repository.cryptoMetadata() != null) {
+            repository.cryptoMetadata().toXContent(repository.cryptoMetadata(), builder, params);
+        }
+        Settings settings = repository.settings();
+        if (SYSTEM_REPOSITORY_SETTING.get(settings)) {
+            settings = repository.settings().filter(s -> !s.equals(SYSTEM_REPOSITORY_SETTING.getKey()));
+        }
         builder.startObject("settings");
-        repository.settings().toXContent(builder, params);
+        settings.toXContent(builder, params);
         builder.endObject();
 
         if (params.paramAsBoolean(HIDE_GENERATIONS_PARAM, false) == false) {
@@ -289,6 +307,6 @@ public static void toXContent(RepositoryMetadata repository, XContentBuilder bui
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/RepositoryMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/RepositoryMetadata.java
index d839e4bafade7..58637df4efe8f 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/RepositoryMetadata.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/RepositoryMetadata.java
@@ -33,10 +33,10 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.repositories.RepositoryData;
 
 import java.io.IOException;
@@ -44,6 +44,8 @@
 
 /**
  * Metadata about registered repository
+ *
+ * @opensearch.internal
  */
 public class RepositoryMetadata implements Writeable {
 
@@ -52,6 +54,7 @@ public class RepositoryMetadata implements Writeable {
     private final String name;
     private final String type;
     private final Settings settings;
+    private final CryptoMetadata cryptoMetadata;
 
     /**
      * Safe repository generation.
@@ -71,14 +74,29 @@ public class RepositoryMetadata implements Writeable {
      * @param settings repository settings
      */
     public RepositoryMetadata(String name, String type, Settings settings) {
-        this(name, type, settings, RepositoryData.UNKNOWN_REPO_GEN, RepositoryData.EMPTY_REPO_GEN);
+        this(name, type, settings, RepositoryData.UNKNOWN_REPO_GEN, RepositoryData.EMPTY_REPO_GEN, null);
+    }
+
+    public RepositoryMetadata(String name, String type, Settings settings, CryptoMetadata cryptoMetadata) {
+        this(name, type, settings, RepositoryData.UNKNOWN_REPO_GEN, RepositoryData.EMPTY_REPO_GEN, cryptoMetadata);
     }
 
     public RepositoryMetadata(RepositoryMetadata metadata, long generation, long pendingGeneration) {
-        this(metadata.name, metadata.type, metadata.settings, generation, pendingGeneration);
+        this(metadata.name, metadata.type, metadata.settings, generation, pendingGeneration, metadata.cryptoMetadata);
     }
 
     public RepositoryMetadata(String name, String type, Settings settings, long generation, long pendingGeneration) {
+        this(name, type, settings, generation, pendingGeneration, null);
+    }
+
+    public RepositoryMetadata(
+        String name,
+        String type,
+        Settings settings,
+        long generation,
+        long pendingGeneration,
+        CryptoMetadata cryptoMetadata
+    ) {
         this.name = name;
         this.type = type;
         this.settings = settings;
@@ -89,6 +107,7 @@ public RepositoryMetadata(String name, String type, Settings settings, long gene
             + "] must be greater or equal to generation ["
             + generation
             + "]";
+        this.cryptoMetadata = cryptoMetadata;
     }
 
     /**
@@ -118,6 +137,15 @@ public Settings settings() {
         return this.settings;
     }
 
+    /**
+     * Returns crypto metadata of repository
+     *
+     * @return crypto metadata of repository
+     */
+    public CryptoMetadata cryptoMetadata() {
+        return this.cryptoMetadata;
+    }
+
     /**
      * Returns the safe repository generation. {@link RepositoryData} for this generation is assumed to exist in the repository.
      * All operations on the repository must be based on the {@link RepositoryData} at this generation.
@@ -153,6 +181,11 @@ public RepositoryMetadata(StreamInput in) throws IOException {
             generation = RepositoryData.UNKNOWN_REPO_GEN;
             pendingGeneration = RepositoryData.EMPTY_REPO_GEN;
         }
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            cryptoMetadata = in.readOptionalWriteable(CryptoMetadata::new);
+        } else {
+            cryptoMetadata = null;
+        }
     }
 
     /**
@@ -169,6 +202,9 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(generation);
             out.writeLong(pendingGeneration);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalWriteable(cryptoMetadata);
+        }
     }
 
     /**
@@ -178,7 +214,10 @@ public void writeTo(StreamOutput out) throws IOException {
      * @return {@code true} if both instances equal in all fields but the generation fields
      */
     public boolean equalsIgnoreGenerations(RepositoryMetadata other) {
-        return name.equals(other.name) && type.equals(other.type()) && settings.equals(other.settings());
+        return name.equals(other.name)
+            && type.equals(other.type())
+            && settings.equals(other.settings())
+            && Objects.equals(cryptoMetadata, other.cryptoMetadata());
     }
 
     @Override
@@ -192,16 +231,21 @@ public boolean equals(Object o) {
         if (!type.equals(that.type)) return false;
         if (generation != that.generation) return false;
         if (pendingGeneration != that.pendingGeneration) return false;
-        return settings.equals(that.settings);
+        if (!settings.equals(that.settings)) return false;
+        return Objects.equals(cryptoMetadata, that.cryptoMetadata);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(name, type, settings, generation, pendingGeneration);
+        return Objects.hash(name, type, settings, generation, pendingGeneration, cryptoMetadata);
     }
 
     @Override
     public String toString() {
-        return "RepositoryMetadata{" + name + "}{" + type + "}{" + settings + "}{" + generation + "}{" + pendingGeneration + "}";
+        String toStr = "RepositoryMetadata{" + name + "}{" + type + "}{" + settings + "}{" + generation + "}{" + pendingGeneration + "}";
+        if (cryptoMetadata != null) {
+            return toStr + "{" + cryptoMetadata + "}";
+        }
+        return toStr;
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/SystemIndexMetadataUpgradeService.java b/server/src/main/java/org/opensearch/cluster/metadata/SystemIndexMetadataUpgradeService.java
index 51a2557ef80bb..22d7235fd1f98 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/SystemIndexMetadataUpgradeService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/SystemIndexMetadataUpgradeService.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.ClusterChangedEvent;
@@ -40,14 +39,16 @@
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.indices.SystemIndices;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 /**
  * A service responsible for updating the metadata used by system indices.
+ *
+ * @opensearch.internal
  */
 public class SystemIndexMetadataUpgradeService implements ClusterStateListener {
 
@@ -56,9 +57,9 @@ public class SystemIndexMetadataUpgradeService implements ClusterStateListener {
     private final SystemIndices systemIndices;
     private final ClusterService clusterService;
 
-    private boolean master = false;
+    private boolean clusterManager = false;
 
-    private volatile ImmutableOpenMap<String, IndexMetadata> lastIndexMetadataMap = ImmutableOpenMap.of();
+    private volatile Map<String, IndexMetadata> lastIndexMetadataMap = Map.of();
     private volatile boolean updateTaskPending = false;
 
     public SystemIndexMetadataUpgradeService(SystemIndices systemIndices, ClusterService clusterService) {
@@ -68,17 +69,17 @@ public SystemIndexMetadataUpgradeService(SystemIndices systemIndices, ClusterSer
 
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
-        if (event.localNodeMaster() != master) {
-            this.master = event.localNodeMaster();
+        if (event.localNodeClusterManager() != clusterManager) {
+            this.clusterManager = event.localNodeClusterManager();
         }
 
-        if (master && updateTaskPending == false) {
-            final ImmutableOpenMap<String, IndexMetadata> indexMetadataMap = event.state().metadata().indices();
+        if (clusterManager && updateTaskPending == false) {
+            final Map<String, IndexMetadata> indexMetadataMap = event.state().metadata().indices();
 
             if (lastIndexMetadataMap != indexMetadataMap) {
-                for (ObjectObjectCursor<String, IndexMetadata> cursor : indexMetadataMap) {
-                    if (cursor.value != lastIndexMetadataMap.get(cursor.key)) {
-                        if (systemIndices.isSystemIndex(cursor.value.getIndex()) != cursor.value.isSystem()) {
+                for (final Map.Entry<String, IndexMetadata> cursor : indexMetadataMap.entrySet()) {
+                    if (cursor.getValue() != lastIndexMetadataMap.get(cursor.getKey())) {
+                        if (systemIndices.isSystemIndex(cursor.getValue().getIndex()) != cursor.getValue().isSystem()) {
                             updateTaskPending = true;
                             clusterService.submitStateUpdateTask(
                                 "system_index_metadata_upgrade_service {system metadata change}",
@@ -92,16 +93,21 @@ public void clusterChanged(ClusterChangedEvent event) {
         }
     }
 
+    /**
+     * Task to update system index metadata.
+     *
+     * @opensearch.internal
+     */
     public class SystemIndexMetadataUpdateTask extends ClusterStateUpdateTask {
 
         @Override
         public ClusterState execute(ClusterState currentState) throws Exception {
-            final ImmutableOpenMap<String, IndexMetadata> indexMetadataMap = currentState.metadata().indices();
+            final Map<String, IndexMetadata> indexMetadataMap = currentState.metadata().indices();
             final List<IndexMetadata> updatedMetadata = new ArrayList<>();
-            for (ObjectObjectCursor<String, IndexMetadata> cursor : indexMetadataMap) {
-                if (cursor.value != lastIndexMetadataMap.get(cursor.key)) {
-                    if (systemIndices.isSystemIndex(cursor.value.getIndex()) != cursor.value.isSystem()) {
-                        updatedMetadata.add(IndexMetadata.builder(cursor.value).system(!cursor.value.isSystem()).build());
+            for (Map.Entry<String, IndexMetadata> cursor : indexMetadataMap.entrySet()) {
+                if (cursor.getValue() != lastIndexMetadataMap.get(cursor.getKey())) {
+                    if (systemIndices.isSystemIndex(cursor.getValue().getIndex()) != cursor.getValue().isSystem()) {
+                        updatedMetadata.add(IndexMetadata.builder(cursor.getValue()).system(!cursor.getValue().isSystem()).build());
                     }
                 }
             }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/Template.java b/server/src/main/java/org/opensearch/cluster/metadata/Template.java
index 0a070ced198c6..8e367c71ed166 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/Template.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/Template.java
@@ -34,19 +34,18 @@
 
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
@@ -58,6 +57,8 @@
  * A template consists of optional settings, mappings, or alias configuration for an index, however,
  * it is entirely independent from an index. It's a building block forming part of a regular index
  * template and a {@link ComponentTemplate}.
+ *
+ * @opensearch.internal
  */
 public class Template extends AbstractDiffable<Template> implements ToXContentObject {
     private static final ParseField SETTINGS = new ParseField("settings");
@@ -75,7 +76,7 @@ public class Template extends AbstractDiffable<Template> implements ToXContentOb
         PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> Settings.fromXContent(p), SETTINGS);
         PARSER.declareObject(
             ConstructingObjectParser.optionalConstructorArg(),
-            (p, c) -> new CompressedXContent(Strings.toString(XContentFactory.jsonBuilder().map(p.mapOrdered()))),
+            (p, c) -> new CompressedXContent(MediaTypeRegistry.JSON.contentBuilder().map(p.mapOrdered()).toString()),
             MAPPINGS
         );
         PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> {
@@ -174,7 +175,7 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
@@ -186,8 +187,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.endObject();
         }
         if (this.mappings != null) {
-            Map<String, Object> uncompressedMapping = XContentHelper.convertToMap(this.mappings.uncompressed(), true, XContentType.JSON)
-                .v2();
+            Map<String, Object> uncompressedMapping = XContentHelper.convertToMap(
+                this.mappings.uncompressed(),
+                true,
+                MediaTypeRegistry.JSON
+            ).v2();
             if (uncompressedMapping.size() > 0) {
                 builder.field(MAPPINGS.getPreferredName());
                 builder.map(reduceMapping(uncompressedMapping));
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/TemplateUpgradeService.java b/server/src/main/java/org/opensearch/cluster/metadata/TemplateUpgradeService.java
index 2623280d49d45..10f458561bffe 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/TemplateUpgradeService.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/TemplateUpgradeService.java
@@ -32,12 +32,10 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequest;
 import org.opensearch.action.admin.indices.template.put.PutIndexTemplateRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
@@ -47,13 +45,13 @@
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.indices.IndexTemplateMissingException;
 import org.opensearch.plugins.Plugin;
@@ -74,6 +72,8 @@
 
 /**
  * Upgrades Templates on behalf of installed {@link Plugin}s when a node joins the cluster
+ *
+ * @opensearch.internal
  */
 public class TemplateUpgradeService implements ClusterStateListener {
 
@@ -89,7 +89,7 @@ public class TemplateUpgradeService implements ClusterStateListener {
 
     final AtomicInteger upgradesInProgress = new AtomicInteger();
 
-    private ImmutableOpenMap<String, IndexTemplateMetadata> lastTemplateMetadata;
+    private Map<String, IndexTemplateMetadata> lastTemplateMetadata;
 
     public TemplateUpgradeService(
         Client client,
@@ -107,7 +107,7 @@ public TemplateUpgradeService(
             }
             return upgradedTemplates;
         };
-        if (DiscoveryNode.isMasterNode(clusterService.getSettings())) {
+        if (DiscoveryNode.isClusterManagerNode(clusterService.getSettings())) {
             clusterService.addListener(this);
         }
     }
@@ -115,7 +115,7 @@ public TemplateUpgradeService(
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
         ClusterState state = event.state();
-        if (state.nodes().isLocalNodeElectedMaster() == false) {
+        if (state.nodes().isLocalNodeElectedClusterManager() == false) {
             return;
         }
         if (state.blocks().hasGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK)) {
@@ -129,7 +129,7 @@ public void clusterChanged(ClusterChangedEvent event) {
             return;
         }
 
-        ImmutableOpenMap<String, IndexTemplateMetadata> templates = state.getMetadata().getTemplates();
+        final Map<String, IndexTemplateMetadata> templates = state.getMetadata().getTemplates();
 
         if (templates == lastTemplateMetadata) {
             // we already checked these sets of templates - no reason to check it again
@@ -162,8 +162,11 @@ void upgradeTemplates(Map<String, BytesReference> changes, Set<String> deletions
         }
 
         for (Map.Entry<String, BytesReference> change : changes.entrySet()) {
-            PutIndexTemplateRequest request = new PutIndexTemplateRequest(change.getKey()).source(change.getValue(), XContentType.JSON);
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1));
+            PutIndexTemplateRequest request = new PutIndexTemplateRequest(change.getKey()).source(
+                change.getValue(),
+                MediaTypeRegistry.JSON
+            );
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1));
             client.admin().indices().putTemplate(request, new ActionListener<AcknowledgedResponse>() {
                 @Override
                 public void onResponse(AcknowledgedResponse response) {
@@ -185,7 +188,7 @@ public void onFailure(Exception e) {
 
         for (String template : deletions) {
             DeleteIndexTemplateRequest request = new DeleteIndexTemplateRequest(template);
-            request.masterNodeTimeout(TimeValue.timeValueMinutes(1));
+            request.clusterManagerNodeTimeout(TimeValue.timeValueMinutes(1));
             client.admin().indices().deleteTemplate(request, new ActionListener<AcknowledgedResponse>() {
                 @Override
                 public void onResponse(AcknowledgedResponse response) {
@@ -223,9 +226,7 @@ void tryFinishUpgrade(AtomicBoolean anyUpgradeFailed) {
                 // Check upgraders are satisfied after the update completed. If they still
                 // report that changes are required, this might indicate a bug or that something
                 // else tinkering with the templates during the upgrade.
-                final ImmutableOpenMap<String, IndexTemplateMetadata> upgradedTemplates = clusterService.state()
-                    .getMetadata()
-                    .getTemplates();
+                final Map<String, IndexTemplateMetadata> upgradedTemplates = clusterService.state().getMetadata().getTemplates();
                 final boolean changesRequired = calculateTemplateChanges(upgradedTemplates).isPresent();
                 if (changesRequired) {
                     logger.warn("Templates are still reported as out of date after the upgrade. The template upgrade will be retried.");
@@ -237,13 +238,11 @@ void tryFinishUpgrade(AtomicBoolean anyUpgradeFailed) {
         }
     }
 
-    Optional<Tuple<Map<String, BytesReference>, Set<String>>> calculateTemplateChanges(
-        ImmutableOpenMap<String, IndexTemplateMetadata> templates
-    ) {
+    Optional<Tuple<Map<String, BytesReference>, Set<String>>> calculateTemplateChanges(final Map<String, IndexTemplateMetadata> templates) {
         // collect current templates
         Map<String, IndexTemplateMetadata> existingMap = new HashMap<>();
-        for (ObjectObjectCursor<String, IndexTemplateMetadata> customCursor : templates) {
-            existingMap.put(customCursor.key, customCursor.value);
+        for (Map.Entry<String, IndexTemplateMetadata> customCursor : templates.entrySet()) {
+            existingMap.put(customCursor.getKey(), customCursor.getValue());
         }
         // upgrade global custom meta data
         Map<String, IndexTemplateMetadata> upgradedMap = indexTemplateMetadataUpgraders.apply(existingMap);
@@ -273,7 +272,7 @@ private BytesReference toBytesReference(IndexTemplateMetadata templateMetadata)
             return XContentHelper.toXContent((builder, params) -> {
                 IndexTemplateMetadata.Builder.toInnerXContentWithTypes(templateMetadata, builder, params);
                 return builder;
-            }, XContentType.JSON, PARAMS, false);
+            }, MediaTypeRegistry.JSON, PARAMS, false);
         } catch (IOException ex) {
             throw new IllegalStateException("Cannot serialize template [" + templateMetadata.getName() + "]", ex);
         }
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/WeightedRoutingMetadata.java b/server/src/main/java/org/opensearch/cluster/metadata/WeightedRoutingMetadata.java
new file mode 100644
index 0000000000000..cc56a0daf6db7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/metadata/WeightedRoutingMetadata.java
@@ -0,0 +1,197 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.Version;
+import org.opensearch.cluster.AbstractNamedDiffable;
+import org.opensearch.cluster.NamedDiff;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Contains metadata for weighted routing
+ *
+ * @opensearch.internal
+ */
+public class WeightedRoutingMetadata extends AbstractNamedDiffable<Metadata.Custom> implements Metadata.Custom {
+    private static final Logger logger = LogManager.getLogger(WeightedRoutingMetadata.class);
+    public static final String TYPE = "weighted_shard_routing";
+    public static final String AWARENESS = "awareness";
+    public static final String VERSION = "_version";
+    public static final long INITIAL_VERSION = -1;
+    public static final long VERSION_UNSET_VALUE = -2;
+    public static final int WEIGHED_AWAY_WEIGHT = 0;
+
+    public long getVersion() {
+        return version;
+    }
+
+    private long version;
+    private WeightedRouting weightedRouting;
+
+    public WeightedRouting getWeightedRouting() {
+        return weightedRouting;
+    }
+
+    public WeightedRoutingMetadata setWeightedRouting(WeightedRouting weightedRouting) {
+        this.weightedRouting = weightedRouting;
+        return this;
+    }
+
+    public WeightedRoutingMetadata(StreamInput in) throws IOException {
+        if (in.available() != 0) {
+            this.weightedRouting = new WeightedRouting(in);
+            this.version = in.readLong();
+        }
+    }
+
+    public WeightedRoutingMetadata(WeightedRouting weightedRouting, long version) {
+        this.weightedRouting = weightedRouting;
+        this.version = version;
+    }
+
+    @Override
+    public EnumSet<Metadata.XContentContext> context() {
+        return Metadata.API_AND_GATEWAY;
+    }
+
+    @Override
+    public String getWriteableName() {
+        return TYPE;
+    }
+
+    @Override
+    public Version getMinimalSupportedVersion() {
+        return Version.V_2_4_0;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        if (weightedRouting != null) {
+            weightedRouting.writeTo(out);
+            out.writeLong(version);
+        }
+    }
+
+    public static NamedDiff<Metadata.Custom> readDiffFrom(StreamInput in) throws IOException {
+        return readDiffFrom(Metadata.Custom.class, TYPE, in);
+    }
+
+    public static WeightedRoutingMetadata fromXContent(XContentParser parser) throws IOException {
+        String attrKey = null;
+        Double attrValue;
+        String attributeName = null;
+        Map<String, Double> weights = new HashMap<>();
+        WeightedRouting weightedRouting;
+        XContentParser.Token token;
+        String awarenessField;
+        String versionAttr = null;
+        long version = VERSION_UNSET_VALUE;
+
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                String attr = parser.currentName();
+                if (attr != null && attr.equals(VERSION)) {
+                    versionAttr = parser.currentName();
+                    continue;
+                } else {
+                    awarenessField = parser.currentName();
+                }
+                if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                    throw new OpenSearchParseException("failed to parse weighted routing metadata  [{}], expected object", awarenessField);
+                }
+                while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                    attributeName = parser.currentName();
+                    if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
+                        throw new OpenSearchParseException(
+                            "failed to parse weighted routing metadata  [{}], expected object",
+                            attributeName
+                        );
+                    }
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                        if (token == XContentParser.Token.FIELD_NAME) {
+                            attrKey = parser.currentName();
+
+                        } else if (token == XContentParser.Token.VALUE_NUMBER) {
+                            if (attrKey != null && attrKey.equals(VERSION)) {
+                                version = Long.parseLong(parser.text());
+                            } else {
+                                attrValue = Double.parseDouble(parser.text());
+                                weights.put(attrKey, attrValue);
+                            }
+
+                        } else {
+                            throw new OpenSearchParseException(
+                                "failed to parse weighted routing metadata attribute " + "[{}], unknown type",
+                                attributeName
+                            );
+                        }
+                    }
+                }
+            } else if (token == XContentParser.Token.VALUE_NUMBER) {
+                if (versionAttr != null && versionAttr.equals(VERSION)) {
+                    version = Long.parseLong(parser.text());
+                }
+            }
+        }
+        weightedRouting = new WeightedRouting(attributeName, weights);
+        return new WeightedRoutingMetadata(weightedRouting, version);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        WeightedRoutingMetadata that = (WeightedRoutingMetadata) o;
+        return weightedRouting.equals(that.weightedRouting);
+    }
+
+    @Override
+    public int hashCode() {
+        return weightedRouting.hashCode();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        toXContent(weightedRouting, builder, version);
+        return builder;
+    }
+
+    public static void toXContent(WeightedRouting weightedRouting, XContentBuilder builder, long version) throws IOException {
+        builder.startObject(AWARENESS);
+        if (weightedRouting.isSet()) {
+            builder.startObject(weightedRouting.attributeName());
+            for (Map.Entry<String, Double> entry : weightedRouting.weights().entrySet()) {
+                builder.field(entry.getKey(), entry.getValue());
+            }
+            builder.endObject();
+        }
+        builder.endObject();
+        builder.field(VERSION, version);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/package-info.java b/server/src/main/java/org/opensearch/cluster/metadata/package-info.java
new file mode 100644
index 0000000000000..ef618b435b3fb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/metadata/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster metadata foundation classes. */
+package org.opensearch.cluster.metadata;
diff --git a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java
index 6bd943c5e1d0d..1e2ed39924efe 100644
--- a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java
+++ b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java
@@ -35,15 +35,17 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.node.Node;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -52,6 +54,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
@@ -61,19 +64,23 @@
 import java.util.stream.Stream;
 
 import static org.opensearch.node.NodeRoleSettings.NODE_ROLES_SETTING;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX;
 
 /**
  * A discovery node represents a node that is part of the cluster.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class DiscoveryNode implements Writeable, ToXContentFragment {
 
     static final String COORDINATING_ONLY = "coordinating_only";
 
     public static boolean nodeRequiresLocalStorage(Settings settings) {
         boolean localStorageEnable = Node.NODE_LOCAL_STORAGE_SETTING.get(settings);
-        if (localStorageEnable == false && (isDataNode(settings) || isMasterNode(settings))) {
+        if (localStorageEnable == false && (isDataNode(settings) || isClusterManagerNode(settings))) {
             // TODO: make this a proper setting validation logic, requiring multi-settings validation
-            throw new IllegalArgumentException("storage can not be disabled for master and data nodes");
+            throw new IllegalArgumentException("storage can not be disabled for cluster-manager and data nodes");
         }
         return localStorageEnable;
     }
@@ -93,10 +100,16 @@ public static boolean hasRole(final Settings settings, final DiscoveryNodeRole r
         }
     }
 
-    public static boolean isMasterNode(Settings settings) {
+    public static boolean isClusterManagerNode(Settings settings) {
         return hasRole(settings, DiscoveryNodeRole.MASTER_ROLE) || hasRole(settings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isClusterManagerNode(Settings)} */
+    @Deprecated
+    public static boolean isMasterNode(Settings settings) {
+        return isClusterManagerNode(settings);
+    }
+
     /**
      * Due to the way that plugins may not be available when settings are being initialized,
      * not all roles may be available from a static/initializing context such as a {@link Setting}
@@ -114,6 +127,10 @@ public static boolean isRemoteClusterClient(final Settings settings) {
         return hasRole(settings, DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE);
     }
 
+    public static boolean isSearchNode(Settings settings) {
+        return hasRole(settings, DiscoveryNodeRole.SEARCH_ROLE);
+    }
+
     private final String nodeName;
     private final String nodeId;
     private final String ephemeralId;
@@ -268,16 +285,34 @@ public static DiscoveryNode createLocal(Settings settings, TransportAddress publ
         return new DiscoveryNode(Node.NODE_NAME_SETTING.get(settings), nodeId, publishAddress, attributes, roles, Version.CURRENT);
     }
 
+    /** Creates a DiscoveryNode representing the local node and verifies the repository. */
+    public static DiscoveryNode createRemoteNodeLocal(
+        Settings settings,
+        TransportAddress publishAddress,
+        String nodeId,
+        RemoteStoreNodeService remoteStoreNodeService
+    ) {
+        Map<String, String> attributes = Node.NODE_ATTRIBUTES.getAsMap(settings);
+        Set<DiscoveryNodeRole> roles = getRolesFromSettings(settings);
+        DiscoveryNode discoveryNode = new DiscoveryNode(
+            Node.NODE_NAME_SETTING.get(settings),
+            nodeId,
+            publishAddress,
+            attributes,
+            roles,
+            Version.CURRENT
+        );
+        remoteStoreNodeService.createAndVerifyRepositories(discoveryNode);
+        return discoveryNode;
+    }
+
     /** extract node roles from the given settings */
     public static Set<DiscoveryNodeRole> getRolesFromSettings(final Settings settings) {
         if (NODE_ROLES_SETTING.exists(settings)) {
             validateLegacySettings(settings, roleMap);
             return Collections.unmodifiableSet(new HashSet<>(NODE_ROLES_SETTING.get(settings)));
         } else {
-            return roleMap.values()
-                .stream()
-                .filter(s -> s.legacySetting() != null && s.legacySetting().get(settings))
-                .collect(Collectors.toSet());
+            return roleMap.values().stream().filter(s -> s.isEnabledByDefault(settings)).collect(Collectors.toSet());
         }
     }
 
@@ -326,7 +361,11 @@ public DiscoveryNode(StreamInput in) throws IOException {
                 }
                 final DiscoveryNodeRole role = roleMap.get(roleName);
                 if (role == null) {
-                    roles.add(new DiscoveryNodeRole.UnknownRole(roleName, roleNameAbbreviation, canContainData));
+                    if (in.getVersion().onOrAfter(Version.V_2_1_0)) {
+                        roles.add(new DiscoveryNodeRole.DynamicRole(roleName, roleNameAbbreviation, canContainData));
+                    } else {
+                        roles.add(new DiscoveryNodeRole.UnknownRole(roleName, roleNameAbbreviation, canContainData));
+                    }
                 } else {
                     assert roleName.equals(role.roleName()) : "role name [" + roleName + "] does not match role [" + role.roleName() + "]";
                     assert roleNameAbbreviation.equals(role.roleNameAbbreviation()) : "role name abbreviation ["
@@ -357,7 +396,7 @@ public DiscoveryNode(StreamInput in) throws IOException {
             }
         }
         this.roles = Collections.unmodifiableSortedSet(new TreeSet<>(roles));
-        this.version = Version.readVersion(in);
+        this.version = in.readVersion();
     }
 
     @Override
@@ -400,9 +439,9 @@ public void writeTo(StreamOutput out) throws IOException {
             }
         }
         if (out.getVersion().before(Version.V_1_0_0) && version.onOrAfter(Version.V_1_0_0)) {
-            Version.writeVersion(LegacyESVersion.V_7_10_2, out);
+            out.writeVersion(LegacyESVersion.V_7_10_2);
         } else {
-            Version.writeVersion(version, out);
+            out.writeVersion(version);
         }
     }
 
@@ -453,12 +492,22 @@ public boolean isDataNode() {
     }
 
     /**
-     * Can this node become master or not.
+     * Can this node become cluster-manager or not.
      */
-    public boolean isMasterNode() {
+    public boolean isClusterManagerNode() {
         return roles.contains(DiscoveryNodeRole.MASTER_ROLE) || roles.contains(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
     }
 
+    /**
+     * Can this node become cluster-manager or not.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isClusterManagerNode()}
+     */
+    @Deprecated
+    public boolean isMasterNode() {
+        return isClusterManagerNode();
+    }
+
     /**
      * Returns a boolean that tells whether this an ingest node or not
      */
@@ -475,6 +524,24 @@ public boolean isRemoteClusterClient() {
         return roles.contains(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE);
     }
 
+    /**
+     * Returns whether the node is dedicated to provide search capability.
+     *
+     * @return true if the node contains search role, false otherwise
+     */
+    public boolean isSearchNode() {
+        return roles.contains(DiscoveryNodeRole.SEARCH_ROLE);
+    }
+
+    /**
+     * Returns whether the node is a remote store node.
+     *
+     * @return true if the node contains remote store node attributes, false otherwise
+     */
+    public boolean isRemoteStoreNode() {
+        return this.getAttributes().keySet().stream().anyMatch(key -> key.startsWith(REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX));
+    }
+
     /**
      * Returns a set of all the roles that the node has. The roles are returned in sorted order by the role name.
      * <p>
@@ -565,10 +632,12 @@ private static Map<String, DiscoveryNodeRole> rolesToMap(final Stream<DiscoveryN
     private static Map<String, DiscoveryNodeRole> roleMap = rolesToMap(DiscoveryNodeRole.BUILT_IN_ROLES.stream());
 
     public static DiscoveryNodeRole getRoleFromRoleName(final String roleName) {
-        if (roleMap.containsKey(roleName) == false) {
-            throw new IllegalArgumentException("unknown role [" + roleName + "]");
+        // As we are supporting dynamic role, should make role name case-insensitive to avoid confusion of role name like "Data"/"DATA"
+        String lowerCasedRoleName = Objects.requireNonNull(roleName).toLowerCase(Locale.ROOT);
+        if (roleMap.containsKey(lowerCasedRoleName)) {
+            return roleMap.get(lowerCasedRoleName);
         }
-        return roleMap.get(roleName);
+        return new DiscoveryNodeRole.DynamicRole(lowerCasedRoleName, lowerCasedRoleName, false);
     }
 
     public static Set<DiscoveryNodeRole> getPossibleRoles() {
@@ -591,11 +660,18 @@ public static void setAdditionalRoles(final Set<DiscoveryNodeRole> additionalRol
             + "], roles by name abbreviation ["
             + roleNameAbbreviationToPossibleRoles
             + "]";
-        // TODO: Remove the Map 'roleNameToPossibleRolesWithMaster' and let 'roleMap = roleNameToPossibleRoles', after removing MASTER_ROLE.
-        // It's used to allow CLUSTER_MANAGER_ROLE that introduced in 2.0, having the same abbreviation name with MASTER_ROLE.
-        final Map<String, DiscoveryNodeRole> roleNameToPossibleRolesWithMaster = new HashMap<>(roleNameToPossibleRoles);
-        roleNameToPossibleRolesWithMaster.put(DiscoveryNodeRole.MASTER_ROLE.roleName(), DiscoveryNodeRole.MASTER_ROLE);
-        roleMap = Collections.unmodifiableMap(roleNameToPossibleRolesWithMaster);
+        roleMap = roleNameToPossibleRoles;
+    }
+
+    /**
+     * Load the deprecated {@link DiscoveryNodeRole#MASTER_ROLE}.
+     * Master role is not added into BUILT_IN_ROLES, because {@link #setAdditionalRoles(Set)} check role name abbreviation duplication,
+     * and CLUSTER_MANAGER_ROLE has the same abbreviation name with MASTER_ROLE.
+     */
+    public static void setDeprecatedMasterRole() {
+        final Map<String, DiscoveryNodeRole> modifiableRoleMap = new HashMap<>(roleMap);
+        modifiableRoleMap.put(DiscoveryNodeRole.MASTER_ROLE.roleName(), DiscoveryNodeRole.MASTER_ROLE);
+        roleMap = Collections.unmodifiableMap(modifiableRoleMap);
     }
 
     public static Set<String> getPossibleRoleNames() {
diff --git a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeFilters.java b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeFilters.java
index d1a81c1286fc5..54f30690f18e1 100644
--- a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeFilters.java
+++ b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeFilters.java
@@ -33,20 +33,30 @@
 package org.opensearch.cluster.node;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
+/**
+ * Filters Discovery nodes
+ *
+ * @opensearch.internal
+ */
 public class DiscoveryNodeFilters {
 
+    /**
+     * Operation type.
+     *
+     * @opensearch.internal
+     */
     public enum OpType {
         AND,
         OR
diff --git a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeRole.java b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeRole.java
index cff1a77f4cdb7..0d2b08656c38d 100644
--- a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeRole.java
+++ b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodeRole.java
@@ -34,6 +34,8 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
+import org.opensearch.common.Booleans;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
@@ -50,13 +52,15 @@
 
 /**
  * Represents a node role.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public abstract class DiscoveryNodeRole implements Comparable<DiscoveryNodeRole> {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DiscoveryNodeRole.class);
     public static final String MASTER_ROLE_DEPRECATION_MESSAGE =
         "Assigning [master] role in setting [node.roles] is deprecated. To promote inclusive language, please use [cluster_manager] role instead.";
-
     private final String roleName;
 
     /**
@@ -93,6 +97,8 @@ public final boolean canContainData() {
 
     private final boolean isKnownRole;
 
+    private final boolean isDynamicRole;
+
     /**
      * Whether this role is known by this node, or is an {@link DiscoveryNodeRole.UnknownRole}.
      */
@@ -100,6 +106,10 @@ public final boolean isKnownRole() {
         return isKnownRole;
     }
 
+    public final boolean isDynamicRole() {
+        return isDynamicRole;
+    }
+
     public boolean isEnabledByDefault(final Settings settings) {
         return legacySetting() != null && legacySetting().get(settings);
     }
@@ -109,18 +119,21 @@ protected DiscoveryNodeRole(final String roleName, final String roleNameAbbrevia
     }
 
     protected DiscoveryNodeRole(final String roleName, final String roleNameAbbreviation, final boolean canContainData) {
-        this(true, roleName, roleNameAbbreviation, canContainData);
+        this(true, false, roleName, roleNameAbbreviation, canContainData);
     }
 
     private DiscoveryNodeRole(
         final boolean isKnownRole,
+        final boolean isDynamicRole,
         final String roleName,
         final String roleNameAbbreviation,
         final boolean canContainData
     ) {
         this.isKnownRole = isKnownRole;
-        this.roleName = Objects.requireNonNull(roleName);
-        this.roleNameAbbreviation = Objects.requireNonNull(roleNameAbbreviation);
+        this.isDynamicRole = isDynamicRole;
+        // As we are supporting dynamic role, should make role name case-insensitive to avoid confusion of role name like "Data"/"DATA"
+        this.roleName = Objects.requireNonNull(roleName).toLowerCase(Locale.ROOT);
+        this.roleNameAbbreviation = Objects.requireNonNull(roleNameAbbreviation).toLowerCase(Locale.ROOT);
         this.canContainData = canContainData;
     }
 
@@ -151,12 +164,13 @@ public final boolean equals(Object o) {
         return roleName.equals(that.roleName)
             && roleNameAbbreviation.equals(that.roleNameAbbreviation)
             && canContainData == that.canContainData
-            && isKnownRole == that.isKnownRole;
+            && isKnownRole == that.isKnownRole
+            && isDynamicRole == that.isDynamicRole;
     }
 
     @Override
     public final int hashCode() {
-        return Objects.hash(isKnownRole, roleName(), roleNameAbbreviation(), canContainData());
+        return Objects.hash(isKnownRole, isDynamicRole, roleName(), roleNameAbbreviation(), canContainData());
     }
 
     @Override
@@ -176,6 +190,7 @@ public final String toString() {
             + ", canContainData="
             + canContainData
             + (isKnownRole ? "" : ", isKnownRole=false")
+            + (isDynamicRole ? "" : ", isDynamicRole=false")
             + '}';
     }
 
@@ -206,7 +221,7 @@ public Setting<Boolean> legacySetting() {
     };
 
     /**
-     * Represents the role for a master-eligible node.
+     * Represents the role for a cluster-manager-eligible node.
      * @deprecated As of 2.0, because promoting inclusive language, replaced by {@link #CLUSTER_MANAGER_ROLE}
      */
     @Deprecated
@@ -233,8 +248,8 @@ public void validateRole(List<DiscoveryNodeRole> roles) {
 
         @Override
         public Setting<Boolean> legacySetting() {
-            // copy the setting here so we can mark it private in org.opensearch.node.Node
-            return Setting.boolSetting("node.master", true, Property.Deprecated, Property.NodeScope);
+            // 'cluster_manager' role should not configure legacy setting since deprecated 'master' role is supported till OS 2.x
+            return null;
         }
 
         @Override
@@ -261,6 +276,10 @@ public void validateRole(List<DiscoveryNodeRole> roles) {
             }
         }
 
+        @Override
+        public boolean isEnabledByDefault(final Settings settings) {
+            return Booleans.isBoolean(settings.get("node.master")) == false;
+        }
     };
 
     public static final DiscoveryNodeRole REMOTE_CLUSTER_CLIENT_ROLE = new DiscoveryNodeRole("remote_cluster_client", "r") {
@@ -278,11 +297,24 @@ public Setting<Boolean> legacySetting() {
 
     };
 
+    /**
+     * Represents the role for a search node, which is dedicated to provide search capability.
+     */
+    public static final DiscoveryNodeRole SEARCH_ROLE = new DiscoveryNodeRole("search", "s", true) {
+
+        @Override
+        public Setting<Boolean> legacySetting() {
+            // search role is added in 2.4 so doesn't need to configure legacy setting
+            return null;
+        }
+
+    };
+
     /**
      * The built-in node roles.
      */
     public static SortedSet<DiscoveryNodeRole> BUILT_IN_ROLES = Collections.unmodifiableSortedSet(
-        new TreeSet<>(Arrays.asList(DATA_ROLE, INGEST_ROLE, CLUSTER_MANAGER_ROLE, REMOTE_CLUSTER_CLIENT_ROLE))
+        new TreeSet<>(Arrays.asList(DATA_ROLE, INGEST_ROLE, CLUSTER_MANAGER_ROLE, REMOTE_CLUSTER_CLIENT_ROLE, SEARCH_ROLE))
     );
 
     /**
@@ -309,7 +341,7 @@ static class UnknownRole extends DiscoveryNodeRole {
          * @param canContainData       whether or not nodes with the role can contain data
          */
         UnknownRole(final String roleName, final String roleNameAbbreviation, final boolean canContainData) {
-            super(false, roleName, roleNameAbbreviation, canContainData);
+            super(false, false, roleName, roleNameAbbreviation, canContainData);
         }
 
         @Override
@@ -321,6 +353,32 @@ public Setting<Boolean> legacySetting() {
 
     }
 
+    /**
+     * Represents a dynamic role. This can occur if a custom role that not in {@link DiscoveryNodeRole#BUILT_IN_ROLES} added for a node.
+     * Some plugin can support extension function with dynamic roles. For example, ML plugin may run machine learning tasks on nodes
+     * with "ml" dynamic role.
+     */
+    static class DynamicRole extends DiscoveryNodeRole {
+
+        /**
+         * Construct a dynamic role with the specified role name and role name abbreviation.
+         *
+         * @param roleName             the role name
+         * @param roleNameAbbreviation the role name abbreviation
+         * @param canContainData       whether or not nodes with the role can contain data
+         */
+        DynamicRole(final String roleName, final String roleNameAbbreviation, final boolean canContainData) {
+            super(false, true, roleName, roleNameAbbreviation, canContainData);
+        }
+
+        @Override
+        public Setting<Boolean> legacySetting() {
+            // return null as dynamic role has no legacy setting
+            return null;
+        }
+
+    }
+
     /**
      * Check if the role is {@link #CLUSTER_MANAGER_ROLE} or {@link #MASTER_ROLE}.
      * @deprecated As of 2.0, because promoting inclusive language. MASTER_ROLE is deprecated.
diff --git a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodes.java b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodes.java
index 1097f3bc245ac..2461e82748ee8 100644
--- a/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodes.java
+++ b/server/src/main/java/org/opensearch/cluster/node/DiscoveryNodes.java
@@ -32,30 +32,29 @@
 
 package org.opensearch.cluster.node;
 
-import com.carrotsearch.hppc.ObjectHashSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Spliterators;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
@@ -63,17 +62,19 @@
 /**
  * This class holds all {@link DiscoveryNode} in the cluster and provides convenience methods to
  * access, modify merge / diff discovery nodes.
+ *
+ * @opensearch.internal
  */
 public class DiscoveryNodes extends AbstractDiffable<DiscoveryNodes> implements Iterable<DiscoveryNode> {
 
     public static final DiscoveryNodes EMPTY_NODES = builder().build();
 
-    private final ImmutableOpenMap<String, DiscoveryNode> nodes;
-    private final ImmutableOpenMap<String, DiscoveryNode> dataNodes;
-    private final ImmutableOpenMap<String, DiscoveryNode> masterNodes;
-    private final ImmutableOpenMap<String, DiscoveryNode> ingestNodes;
+    private final Map<String, DiscoveryNode> nodes;
+    private final Map<String, DiscoveryNode> dataNodes;
+    private final Map<String, DiscoveryNode> clusterManagerNodes;
+    private final Map<String, DiscoveryNode> ingestNodes;
 
-    private final String masterNodeId;
+    private final String clusterManagerNodeId;
     private final String localNodeId;
     private final Version minNonClientNodeVersion;
     private final Version maxNonClientNodeVersion;
@@ -81,22 +82,22 @@ public class DiscoveryNodes extends AbstractDiffable<DiscoveryNodes> implements
     private final Version minNodeVersion;
 
     private DiscoveryNodes(
-        ImmutableOpenMap<String, DiscoveryNode> nodes,
-        ImmutableOpenMap<String, DiscoveryNode> dataNodes,
-        ImmutableOpenMap<String, DiscoveryNode> masterNodes,
-        ImmutableOpenMap<String, DiscoveryNode> ingestNodes,
-        String masterNodeId,
+        final Map<String, DiscoveryNode> nodes,
+        final Map<String, DiscoveryNode> dataNodes,
+        final Map<String, DiscoveryNode> clusterManagerNodes,
+        final Map<String, DiscoveryNode> ingestNodes,
+        String clusterManagerNodeId,
         String localNodeId,
         Version minNonClientNodeVersion,
         Version maxNonClientNodeVersion,
         Version maxNodeVersion,
         Version minNodeVersion
     ) {
-        this.nodes = nodes;
-        this.dataNodes = dataNodes;
-        this.masterNodes = masterNodes;
-        this.ingestNodes = ingestNodes;
-        this.masterNodeId = masterNodeId;
+        this.nodes = Collections.unmodifiableMap(nodes);
+        this.dataNodes = Collections.unmodifiableMap(dataNodes);
+        this.clusterManagerNodes = Collections.unmodifiableMap(clusterManagerNodes);
+        this.ingestNodes = Collections.unmodifiableMap(ingestNodes);
+        this.clusterManagerNodeId = clusterManagerNodeId;
         this.localNodeId = localNodeId;
         this.minNonClientNodeVersion = minNonClientNodeVersion;
         this.maxNonClientNodeVersion = maxNonClientNodeVersion;
@@ -106,18 +107,28 @@ private DiscoveryNodes(
 
     @Override
     public Iterator<DiscoveryNode> iterator() {
-        return nodes.valuesIt();
+        return nodes.values().iterator();
     }
 
     /**
-     * Returns {@code true} if the local node is the elected master node.
+     * Returns {@code true} if the local node is the elected cluster-manager node.
      */
-    public boolean isLocalNodeElectedMaster() {
+    public boolean isLocalNodeElectedClusterManager() {
         if (localNodeId == null) {
             // we don't know yet the local node id, return false
             return false;
         }
-        return localNodeId.equals(masterNodeId);
+        return localNodeId.equals(clusterManagerNodeId);
+    }
+
+    /**
+     * Returns {@code true} if the local node is the elected cluster-manager node.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isLocalNodeElectedClusterManager()}
+     */
+    @Deprecated
+    public boolean isLocalNodeElectedMaster() {
+        return isLocalNodeElectedClusterManager();
     }
 
     /**
@@ -134,7 +145,7 @@ public int getSize() {
      *
      * @return {@link Map} of the discovered nodes arranged by their ids
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getNodes() {
+    public Map<String, DiscoveryNode> getNodes() {
         return this.nodes;
     }
 
@@ -143,60 +154,92 @@ public ImmutableOpenMap<String, DiscoveryNode> getNodes() {
      *
      * @return {@link Map} of the discovered data nodes arranged by their ids
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getDataNodes() {
+    public Map<String, DiscoveryNode> getDataNodes() {
         return this.dataNodes;
     }
 
     /**
-     * Get a {@link Map} of the discovered master nodes arranged by their ids
+     * Get a {@link Map} of the discovered cluster-manager nodes arranged by their ids
+     *
+     * @return {@link Map} of the discovered cluster-manager nodes arranged by their ids
+     */
+    public Map<String, DiscoveryNode> getClusterManagerNodes() {
+        return this.clusterManagerNodes;
+    }
+
+    /**
+     * Get a {@link Map} of the discovered cluster-manager nodes arranged by their ids
      *
-     * @return {@link Map} of the discovered master nodes arranged by their ids
+     * @return {@link Map} of the discovered cluster-manager nodes arranged by their ids
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerNodes()}
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getMasterNodes() {
-        return this.masterNodes;
+    @Deprecated
+    public Map<String, DiscoveryNode> getMasterNodes() {
+        return getClusterManagerNodes();
     }
 
     /**
      * @return All the ingest nodes arranged by their ids
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getIngestNodes() {
+    public Map<String, DiscoveryNode> getIngestNodes() {
         return ingestNodes;
     }
 
     /**
-     * Get a {@link Map} of the discovered master and data nodes arranged by their ids
+     * Get a {@link Map} of the discovered cluster-manager and data nodes arranged by their ids
      *
-     * @return {@link Map} of the discovered master and data nodes arranged by their ids
+     * @return {@link Map} of the discovered cluster-manager and data nodes arranged by their ids
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getMasterAndDataNodes() {
-        ImmutableOpenMap.Builder<String, DiscoveryNode> nodes = ImmutableOpenMap.builder(dataNodes);
-        nodes.putAll(masterNodes);
-        return nodes.build();
+    public Map<String, DiscoveryNode> getClusterManagerAndDataNodes() {
+        final Map<String, DiscoveryNode> nodes = new HashMap<>(dataNodes);
+        nodes.putAll(clusterManagerNodes);
+        return Collections.unmodifiableMap(nodes);
     }
 
     /**
-     * Get a {@link Map} of the coordinating only nodes (nodes which are neither master, nor data, nor ingest nodes) arranged by their ids
+     * Get a {@link Map} of the discovered cluster-manager and data nodes arranged by their ids
+     *
+     * @return {@link Map} of the discovered cluster-manager and data nodes arranged by their ids
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerAndDataNodes()}
+     */
+    @Deprecated
+    public Map<String, DiscoveryNode> getMasterAndDataNodes() {
+        return getClusterManagerAndDataNodes();
+    }
+
+    /**
+     * Get a {@link Map} of the coordinating only nodes (nodes which are neither cluster-manager, nor data, nor ingest nodes) arranged by their ids
      *
      * @return {@link Map} of the coordinating only nodes arranged by their ids
      */
-    public ImmutableOpenMap<String, DiscoveryNode> getCoordinatingOnlyNodes() {
-        ImmutableOpenMap.Builder<String, DiscoveryNode> nodes = ImmutableOpenMap.builder(this.nodes);
-        nodes.removeAll(masterNodes.keys());
-        nodes.removeAll(dataNodes.keys());
-        nodes.removeAll(ingestNodes.keys());
-        return nodes.build();
+    public Map<String, DiscoveryNode> getCoordinatingOnlyNodes() {
+        final HashMap<String, DiscoveryNode> nodes = new HashMap<>(this.nodes);
+        nodes.keySet().removeAll(clusterManagerNodes.keySet());
+        nodes.keySet().removeAll(dataNodes.keySet());
+        nodes.keySet().removeAll(ingestNodes.keySet());
+        return Collections.unmodifiableMap(nodes);
     }
 
     /**
-     * Returns a stream of all nodes, with master nodes at the front
+     * Returns a stream of all nodes, with cluster-manager nodes at the front
      */
-    public Stream<DiscoveryNode> mastersFirstStream() {
+    public Stream<DiscoveryNode> clusterManagersFirstStream() {
         return Stream.concat(
-            StreamSupport.stream(masterNodes.spliterator(), false).map(cur -> cur.value),
-            StreamSupport.stream(this.spliterator(), false).filter(n -> n.isMasterNode() == false)
+            StreamSupport.stream(Spliterators.spliterator(clusterManagerNodes.entrySet(), 0), false).map(cur -> cur.getValue()),
+            StreamSupport.stream(this.spliterator(), false).filter(n -> n.isClusterManagerNode() == false)
         );
     }
 
+    /**
+     * Returns a stream of all nodes, with cluster-manager nodes at the front
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagersFirstStream()}
+     */
+    @Deprecated
+    public Stream<DiscoveryNode> mastersFirstStream() {
+        return clusterManagersFirstStream();
+    }
+
     /**
      * Get a node by its id
      *
@@ -230,7 +273,7 @@ public boolean nodeExists(DiscoveryNode node) {
 
     /**
      * Determine if the given node exists and has the right roles. Supported roles vary by version, and our local cluster state might
-     * have come via an older master, so the roles may differ even if the node is otherwise identical.
+     * have come via an older cluster-manager, so the roles may differ even if the node is otherwise identical.
      */
     public boolean nodeExistsWithSameRoles(DiscoveryNode discoveryNode) {
         final DiscoveryNode existing = nodes.get(discoveryNode.getId());
@@ -239,7 +282,7 @@ public boolean nodeExistsWithSameRoles(DiscoveryNode discoveryNode) {
 
     /**
      * Determine if the given node exists and has the right version. During upgrade from Elasticsearch version as OpenSearch node run in
-     * BWC mode and can have the version as 7.10.2 in cluster state from older master to OpenSearch master.
+     * BWC mode and can have the version as 7.10.2 in cluster state from older cluster-manager to OpenSearch cluster-manager.
      */
     public boolean nodeExistsWithBWCVersion(DiscoveryNode discoveryNode) {
         final DiscoveryNode existing = nodes.get(discoveryNode.getId());
@@ -250,12 +293,23 @@ public boolean nodeExistsWithBWCVersion(DiscoveryNode discoveryNode) {
     }
 
     /**
-     * Get the id of the master node
+     * Get the id of the cluster-manager node
+     *
+     * @return id of the cluster-manager
+     */
+    public String getClusterManagerNodeId() {
+        return this.clusterManagerNodeId;
+    }
+
+    /**
+     * Get the id of the cluster-manager node
      *
-     * @return id of the master
+     * @return id of the cluster-manager
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerNodeId()}
      */
+    @Deprecated
     public String getMasterNodeId() {
-        return this.masterNodeId;
+        return getClusterManagerNodeId();
     }
 
     /**
@@ -277,16 +331,27 @@ public DiscoveryNode getLocalNode() {
     }
 
     /**
-     * Returns the master node, or {@code null} if there is no master node
+     * Returns the cluster-manager node, or {@code null} if there is no cluster-manager node
      */
     @Nullable
-    public DiscoveryNode getMasterNode() {
-        if (masterNodeId != null) {
-            return nodes.get(masterNodeId);
+    public DiscoveryNode getClusterManagerNode() {
+        if (clusterManagerNodeId != null) {
+            return nodes.get(clusterManagerNodeId);
         }
         return null;
     }
 
+    /**
+     * Returns the cluster-manager node, or {@code null} if there is no cluster-manager node
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerNode()}
+     */
+    @Deprecated
+    @Nullable
+    public DiscoveryNode getMasterNode() {
+        return getClusterManagerNode();
+    }
+
     /**
      * Get a node by its address
      *
@@ -294,8 +359,7 @@ public DiscoveryNode getMasterNode() {
      * @return node identified by the given address or <code>null</code> if no such node exists
      */
     public DiscoveryNode findByAddress(TransportAddress address) {
-        for (ObjectCursor<DiscoveryNode> cursor : nodes.values()) {
-            DiscoveryNode node = cursor.value;
+        for (final DiscoveryNode node : nodes.values()) {
             if (node.getAddress().equals(address)) {
                 return node;
             }
@@ -382,7 +446,7 @@ public String[] resolveNodes(String... nodes) {
         if (nodes == null || nodes.length == 0) {
             return StreamSupport.stream(this.spliterator(), false).map(DiscoveryNode::getId).toArray(String[]::new);
         } else {
-            ObjectHashSet<String> resolvedNodesIds = new ObjectHashSet<>(nodes.length);
+            final HashSet<String> resolvedNodesIds = new HashSet<>(nodes.length);
             for (String nodeId : nodes) {
                 if (nodeId == null) {
                     // don't silence the underlying issue, it is a bug, so lets fail if assertions are enabled
@@ -394,9 +458,9 @@ public String[] resolveNodes(String... nodes) {
                         resolvedNodesIds.add(localNodeId);
                     }
                 } else if (nodeId.equals("_master") || nodeId.equals("_cluster_manager")) {
-                    String masterNodeId = getMasterNodeId();
-                    if (masterNodeId != null) {
-                        resolvedNodesIds.add(masterNodeId);
+                    String clusterManagerNodeId = getClusterManagerNodeId();
+                    if (clusterManagerNodeId != null) {
+                        resolvedNodesIds.add(clusterManagerNodeId);
                     }
                 } else if (nodeExists(nodeId)) {
                     resolvedNodesIds.add(nodeId);
@@ -415,27 +479,27 @@ public String[] resolveNodes(String... nodes) {
                         String matchAttrValue = nodeId.substring(index + 1);
                         if (DiscoveryNodeRole.DATA_ROLE.roleName().equals(matchAttrName)) {
                             if (Booleans.parseBoolean(matchAttrValue, true)) {
-                                resolvedNodesIds.addAll(dataNodes.keys());
+                                resolvedNodesIds.addAll(dataNodes.keySet());
                             } else {
-                                resolvedNodesIds.removeAll(dataNodes.keys());
+                                resolvedNodesIds.removeAll(dataNodes.keySet());
                             }
                         } else if (roleNameIsClusterManager(matchAttrName)) {
                             if (Booleans.parseBoolean(matchAttrValue, true)) {
-                                resolvedNodesIds.addAll(masterNodes.keys());
+                                resolvedNodesIds.addAll(clusterManagerNodes.keySet());
                             } else {
-                                resolvedNodesIds.removeAll(masterNodes.keys());
+                                resolvedNodesIds.removeAll(clusterManagerNodes.keySet());
                             }
                         } else if (DiscoveryNodeRole.INGEST_ROLE.roleName().equals(matchAttrName)) {
                             if (Booleans.parseBoolean(matchAttrValue, true)) {
-                                resolvedNodesIds.addAll(ingestNodes.keys());
+                                resolvedNodesIds.addAll(ingestNodes.keySet());
                             } else {
-                                resolvedNodesIds.removeAll(ingestNodes.keys());
+                                resolvedNodesIds.removeAll(ingestNodes.keySet());
                             }
                         } else if (DiscoveryNode.COORDINATING_ONLY.equals(matchAttrName)) {
                             if (Booleans.parseBoolean(matchAttrValue, true)) {
-                                resolvedNodesIds.addAll(getCoordinatingOnlyNodes().keys());
+                                resolvedNodesIds.addAll(getCoordinatingOnlyNodes().keySet());
                             } else {
-                                resolvedNodesIds.removeAll(getCoordinatingOnlyNodes().keys());
+                                resolvedNodesIds.removeAll(getCoordinatingOnlyNodes().keySet());
                             }
                         } else {
                             for (DiscoveryNode node : this) {
@@ -462,7 +526,7 @@ public String[] resolveNodes(String... nodes) {
                     }
                 }
             }
-            return resolvedNodesIds.toArray(String.class);
+            return resolvedNodesIds.toArray(new String[0]);
         }
     }
 
@@ -488,8 +552,8 @@ public Delta delta(DiscoveryNodes other) {
         }
 
         return new Delta(
-            other.getMasterNode(),
-            getMasterNode(),
+            other.getClusterManagerNode(),
+            getClusterManagerNode(),
             localNodeId,
             Collections.unmodifiableList(removed),
             Collections.unmodifiableList(added)
@@ -505,54 +569,79 @@ public String toString() {
             if (node == getLocalNode()) {
                 sb.append(", local");
             }
-            if (node == getMasterNode()) {
-                sb.append(", master");
+            if (node == getClusterManagerNode()) {
+                sb.append(", cluster-manager");
             }
             sb.append("\n");
         }
         return sb.toString();
     }
 
+    /**
+     * Delta between nodes.
+     *
+     * @opensearch.internal
+     */
     public static class Delta {
 
         private final String localNodeId;
         @Nullable
-        private final DiscoveryNode previousMasterNode;
+        private final DiscoveryNode previousClusterManagerNode;
         @Nullable
-        private final DiscoveryNode newMasterNode;
+        private final DiscoveryNode newClusterManagerNode;
         private final List<DiscoveryNode> removed;
         private final List<DiscoveryNode> added;
 
         private Delta(
-            @Nullable DiscoveryNode previousMasterNode,
-            @Nullable DiscoveryNode newMasterNode,
+            @Nullable DiscoveryNode previousClusterManagerNode,
+            @Nullable DiscoveryNode newClusterManagerNode,
             String localNodeId,
             List<DiscoveryNode> removed,
             List<DiscoveryNode> added
         ) {
-            this.previousMasterNode = previousMasterNode;
-            this.newMasterNode = newMasterNode;
+            this.previousClusterManagerNode = previousClusterManagerNode;
+            this.newClusterManagerNode = newClusterManagerNode;
             this.localNodeId = localNodeId;
             this.removed = removed;
             this.added = added;
         }
 
         public boolean hasChanges() {
-            return masterNodeChanged() || !removed.isEmpty() || !added.isEmpty();
+            return clusterManagerNodeChanged() || !removed.isEmpty() || !added.isEmpty();
         }
 
+        public boolean clusterManagerNodeChanged() {
+            return Objects.equals(newClusterManagerNode, previousClusterManagerNode) == false;
+        }
+
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNodeChanged()} */
+        @Deprecated
         public boolean masterNodeChanged() {
-            return Objects.equals(newMasterNode, previousMasterNode) == false;
+            return clusterManagerNodeChanged();
+        }
+
+        @Nullable
+        public DiscoveryNode previousClusterManagerNode() {
+            return previousClusterManagerNode;
         }
 
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #previousClusterManagerNode()} */
+        @Deprecated
         @Nullable
         public DiscoveryNode previousMasterNode() {
-            return previousMasterNode;
+            return previousClusterManagerNode();
+        }
+
+        @Nullable
+        public DiscoveryNode newClusterManagerNode() {
+            return newClusterManagerNode;
         }
 
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #newClusterManagerNode()} */
+        @Deprecated
         @Nullable
         public DiscoveryNode newMasterNode() {
-            return newMasterNode;
+            return newClusterManagerNode();
         }
 
         public boolean removed() {
@@ -573,14 +662,14 @@ public List<DiscoveryNode> addedNodes() {
 
         public String shortSummary() {
             final StringBuilder summary = new StringBuilder();
-            if (masterNodeChanged()) {
-                summary.append("master node changed {previous [");
-                if (previousMasterNode() != null) {
-                    summary.append(previousMasterNode());
+            if (clusterManagerNodeChanged()) {
+                summary.append("cluster-manager node changed {previous [");
+                if (previousClusterManagerNode() != null) {
+                    summary.append(previousClusterManagerNode());
                 }
                 summary.append("], current [");
-                if (newMasterNode() != null) {
-                    summary.append(newMasterNode());
+                if (newClusterManagerNode() != null) {
+                    summary.append(newClusterManagerNode());
                 }
                 summary.append("]}");
             }
@@ -609,11 +698,11 @@ public String shortSummary() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        if (masterNodeId == null) {
+        if (clusterManagerNodeId == null) {
             out.writeBoolean(false);
         } else {
             out.writeBoolean(true);
-            out.writeString(masterNodeId);
+            out.writeString(clusterManagerNodeId);
         }
         out.writeVInt(nodes.size());
         for (DiscoveryNode node : this) {
@@ -624,7 +713,7 @@ public void writeTo(StreamOutput out) throws IOException {
     public static DiscoveryNodes readFrom(StreamInput in, DiscoveryNode localNode) throws IOException {
         Builder builder = new Builder();
         if (in.readBoolean()) {
-            builder.masterNodeId(in.readString());
+            builder.clusterManagerNodeId(in.readString());
         }
         if (localNode != null) {
             builder.localNodeId(localNode.getId());
@@ -656,20 +745,25 @@ public static Builder builder(DiscoveryNodes nodes) {
         return new Builder(nodes);
     }
 
+    /**
+     * Builder of a map of discovery nodes.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
-        private final ImmutableOpenMap.Builder<String, DiscoveryNode> nodes;
-        private String masterNodeId;
+        private final Map<String, DiscoveryNode> nodes;
+        private String clusterManagerNodeId;
         private String localNodeId;
 
         public Builder() {
-            nodes = ImmutableOpenMap.builder();
+            nodes = new HashMap<>();
         }
 
         public Builder(DiscoveryNodes nodes) {
-            this.masterNodeId = nodes.getMasterNodeId();
+            this.clusterManagerNodeId = nodes.getClusterManagerNodeId();
             this.localNodeId = nodes.getLocalNodeId();
-            this.nodes = ImmutableOpenMap.builder(nodes.getNodes());
+            this.nodes = new HashMap<>(nodes.getNodes());
         }
 
         /**
@@ -712,11 +806,17 @@ public Builder remove(DiscoveryNode node) {
             return this;
         }
 
-        public Builder masterNodeId(String masterNodeId) {
-            this.masterNodeId = masterNodeId;
+        public Builder clusterManagerNodeId(String clusterManagerNodeId) {
+            this.clusterManagerNodeId = clusterManagerNodeId;
             return this;
         }
 
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNodeId} */
+        @Deprecated
+        public Builder masterNodeId(String clusterManagerNodeId) {
+            return clusterManagerNodeId(clusterManagerNodeId);
+        }
+
         public Builder localNodeId(String localNodeId) {
             this.localNodeId = localNodeId;
             return this;
@@ -731,8 +831,7 @@ public Builder localNodeId(String localNodeId) {
          * exception
          */
         private String validateAdd(DiscoveryNode node) {
-            for (ObjectCursor<DiscoveryNode> cursor : nodes.values()) {
-                final DiscoveryNode existingNode = cursor.value;
+            for (final DiscoveryNode existingNode : nodes.values()) {
                 if (node.getAddress().equals(existingNode.getAddress()) && node.getId().equals(existingNode.getId()) == false) {
                     return "can't add node " + node + ", found existing node " + existingNode + " with same address";
                 }
@@ -748,22 +847,22 @@ private String validateAdd(DiscoveryNode node) {
         }
 
         public DiscoveryNodes build() {
-            ImmutableOpenMap.Builder<String, DiscoveryNode> dataNodesBuilder = ImmutableOpenMap.builder();
-            ImmutableOpenMap.Builder<String, DiscoveryNode> masterNodesBuilder = ImmutableOpenMap.builder();
-            ImmutableOpenMap.Builder<String, DiscoveryNode> ingestNodesBuilder = ImmutableOpenMap.builder();
+            final Map<String, DiscoveryNode> dataNodesBuilder = new HashMap<>();
+            final Map<String, DiscoveryNode> clusterManagerNodesBuilder = new HashMap<>();
+            final Map<String, DiscoveryNode> ingestNodesBuilder = new HashMap<>();
             Version minNodeVersion = null;
             Version maxNodeVersion = null;
             Version minNonClientNodeVersion = null;
             Version maxNonClientNodeVersion = null;
-            for (ObjectObjectCursor<String, DiscoveryNode> nodeEntry : nodes) {
-                if (nodeEntry.value.isDataNode()) {
-                    dataNodesBuilder.put(nodeEntry.key, nodeEntry.value);
+            for (final Map.Entry<String, DiscoveryNode> nodeEntry : nodes.entrySet()) {
+                if (nodeEntry.getValue().isDataNode()) {
+                    dataNodesBuilder.put(nodeEntry.getKey(), nodeEntry.getValue());
                 }
-                if (nodeEntry.value.isMasterNode()) {
-                    masterNodesBuilder.put(nodeEntry.key, nodeEntry.value);
+                if (nodeEntry.getValue().isClusterManagerNode()) {
+                    clusterManagerNodesBuilder.put(nodeEntry.getKey(), nodeEntry.getValue());
                 }
-                final Version version = nodeEntry.value.getVersion();
-                if (nodeEntry.value.isDataNode() || nodeEntry.value.isMasterNode()) {
+                final Version version = nodeEntry.getValue().getVersion();
+                if (nodeEntry.getValue().isDataNode() || nodeEntry.getValue().isClusterManagerNode()) {
                     if (minNonClientNodeVersion == null) {
                         minNonClientNodeVersion = version;
                         maxNonClientNodeVersion = version;
@@ -772,19 +871,19 @@ public DiscoveryNodes build() {
                         maxNonClientNodeVersion = Version.max(maxNonClientNodeVersion, version);
                     }
                 }
-                if (nodeEntry.value.isIngestNode()) {
-                    ingestNodesBuilder.put(nodeEntry.key, nodeEntry.value);
+                if (nodeEntry.getValue().isIngestNode()) {
+                    ingestNodesBuilder.put(nodeEntry.getKey(), nodeEntry.getValue());
                 }
                 minNodeVersion = minNodeVersion == null ? version : Version.min(minNodeVersion, version);
                 maxNodeVersion = maxNodeVersion == null ? version : Version.max(maxNodeVersion, version);
             }
 
             return new DiscoveryNodes(
-                nodes.build(),
-                dataNodesBuilder.build(),
-                masterNodesBuilder.build(),
-                ingestNodesBuilder.build(),
-                masterNodeId,
+                nodes,
+                dataNodesBuilder,
+                clusterManagerNodesBuilder,
+                ingestNodesBuilder,
+                clusterManagerNodeId,
                 localNodeId,
                 minNonClientNodeVersion == null ? Version.CURRENT : minNonClientNodeVersion,
                 maxNonClientNodeVersion == null ? Version.CURRENT : maxNonClientNodeVersion,
@@ -793,13 +892,19 @@ public DiscoveryNodes build() {
             );
         }
 
+        public boolean isLocalNodeElectedClusterManager() {
+            return clusterManagerNodeId != null && clusterManagerNodeId.equals(localNodeId);
+        }
+
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isLocalNodeElectedClusterManager()} */
+        @Deprecated
         public boolean isLocalNodeElectedMaster() {
-            return masterNodeId != null && masterNodeId.equals(localNodeId);
+            return isLocalNodeElectedClusterManager();
         }
     }
 
     /**
-     * Check if the given name of the node role is 'cluster_manger' or 'master'.
+     * Check if the given name of the node role is 'cluster_manager' or 'master'.
      * The method is added for {@link #resolveNodes} to keep the code clear, when support the both above roles.
      * @deprecated As of 2.0, because promoting inclusive language. MASTER_ROLE is deprecated.
      * @param matchAttrName a given String for a name of the node role.
diff --git a/server/src/main/java/org/opensearch/cluster/node/package-info.java b/server/src/main/java/org/opensearch/cluster/node/package-info.java
new file mode 100644
index 0000000000000..efb3e3d5f0248
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/node/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Node discovery foundation classes. */
+package org.opensearch.cluster.node;
diff --git a/server/src/main/java/org/opensearch/cluster/package-info.java b/server/src/main/java/org/opensearch/cluster/package-info.java
new file mode 100644
index 0000000000000..f9cd00f32a6a6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster level classes. */
+package org.opensearch.cluster;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/AllocationId.java b/server/src/main/java/org/opensearch/cluster/routing/AllocationId.java
index d80ceaec76c20..6e6ea3919c813 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/AllocationId.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/AllocationId.java
@@ -33,15 +33,15 @@
 package org.opensearch.cluster.routing;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -54,6 +54,8 @@
  * the target shard (only materialized in RoutingNodes) is initializing with the id set to the origin shard
  * relocationId. Once relocation is done, the new allocation id is set to the relocationId. This is similar
  * behavior to how ShardRouting#currentNodeId is used.
+ *
+ * @opensearch.internal
  */
 public class AllocationId implements ToXContentObject, Writeable {
     private static final String ID_KEY = "id";
diff --git a/server/src/main/java/org/opensearch/cluster/routing/BatchedRerouteService.java b/server/src/main/java/org/opensearch/cluster/routing/BatchedRerouteService.java
index 05c11e112364a..73137d5b3e538 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/BatchedRerouteService.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/BatchedRerouteService.java
@@ -36,13 +36,13 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -50,8 +50,10 @@
 
 /**
  * A {@link BatchedRerouteService} is a {@link RerouteService} that batches together reroute requests to avoid unnecessary extra reroutes.
- * This component only does meaningful work on the elected master node. Reroute requests will fail with a {@link NotMasterException} on
+ * This component only does meaningful work on the elected cluster-manager node. Reroute requests will fail with a {@link NotClusterManagerException} on
  * other nodes.
+ *
+ * @opensearch.internal
  */
 public class BatchedRerouteService implements RerouteService {
     private static final Logger logger = LogManager.getLogger(BatchedRerouteService.class);
@@ -139,14 +141,17 @@ public ClusterState execute(ClusterState currentState) {
                 }
 
                 @Override
-                public void onNoLongerMaster(String source) {
+                public void onNoLongerClusterManager(String source) {
                     synchronized (mutex) {
                         if (pendingRerouteListeners == currentListeners) {
                             pendingRerouteListeners = null;
                         }
                     }
-                    ActionListener.onFailure(currentListeners, new NotMasterException("delayed reroute [" + reason + "] cancelled"));
-                    // no big deal, the new master will reroute again
+                    ActionListener.onFailure(
+                        currentListeners,
+                        new NotClusterManagerException("delayed reroute [" + reason + "] cancelled")
+                    );
+                    // no big deal, the new cluster-manager will reroute again
                 }
 
                 @Override
diff --git a/server/src/main/java/org/opensearch/cluster/routing/DelayedAllocationService.java b/server/src/main/java/org/opensearch/cluster/routing/DelayedAllocationService.java
index e10103f5b4cec..2e200b6f38612 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/DelayedAllocationService.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/DelayedAllocationService.java
@@ -42,8 +42,8 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.threadpool.Scheduler;
@@ -64,6 +64,8 @@
  * The actual removal of the delay marker happens in
  * {@link AllocationService#removeDelayMarkers(RoutingAllocation)}, triggering yet
  * another cluster change event.
+ *
+ * @opensearch.internal
  */
 public class DelayedAllocationService extends AbstractLifecycleComponent implements ClusterStateListener {
     private static final Logger logger = LogManager.getLogger(DelayedAllocationService.class);
@@ -148,7 +150,7 @@ public DelayedAllocationService(ThreadPool threadPool, ClusterService clusterSer
         this.threadPool = threadPool;
         this.clusterService = clusterService;
         this.allocationService = allocationService;
-        if (DiscoveryNode.isMasterNode(clusterService.getSettings())) {
+        if (DiscoveryNode.isClusterManagerNode(clusterService.getSettings())) {
             clusterService.addListener(this);
         }
     }
@@ -172,7 +174,7 @@ protected long currentNanoTime() {
 
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
-        if (event.localNodeMaster()) {
+        if (event.localNodeClusterManager()) {
             long currentNanoTime = currentNanoTime();
             scheduleIfNeeded(currentNanoTime, event.state());
         }
@@ -194,7 +196,7 @@ private void removeIfSameTask(DelayedRerouteTask expectedTask) {
      * Figure out if an existing scheduled reroute is good enough or whether we need to cancel and reschedule.
      */
     private synchronized void scheduleIfNeeded(long currentNanoTime, ClusterState state) {
-        assertClusterOrMasterStateThread();
+        assertClusterOrClusterManagerStateThread();
         long nextDelayNanos = UnassignedInfo.findNextDelayedAllocation(currentNanoTime, state);
         if (nextDelayNanos < 0) {
             logger.trace("no need to schedule reroute - no delayed unassigned shards");
@@ -234,7 +236,14 @@ private synchronized void scheduleIfNeeded(long currentNanoTime, ClusterState st
     }
 
     // protected so that it can be overridden (and disabled) by unit tests
+    protected void assertClusterOrClusterManagerStateThread() {
+        assert ClusterService.assertClusterOrClusterManagerStateThread();
+    }
+
+    // protected so that it can be overridden (and disabled) by unit tests
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #assertClusterOrClusterManagerStateThread()} */
+    @Deprecated
     protected void assertClusterOrMasterStateThread() {
-        assert ClusterService.assertClusterOrMasterStateThread();
+        assertClusterOrClusterManagerStateThread();
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/FailAwareWeightedRouting.java b/server/src/main/java/org/opensearch/cluster/routing/FailAwareWeightedRouting.java
new file mode 100644
index 0000000000000..1724b26f5475d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/FailAwareWeightedRouting.java
@@ -0,0 +1,150 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.search.SearchShardIterator;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.search.SearchShardTarget;
+
+import java.util.List;
+
+import static org.opensearch.cluster.routing.OperationRouting.IGNORE_WEIGHTED_SHARD_ROUTING;
+
+/**
+ * This class contains logic to find next shard to retry search request in case of failure from other shard copy.
+ * This decides if retryable shard search requests can be tried on shard copies present in data
+ * nodes whose attribute value weight for weighted shard routing is set to zero.
+ */
+
+public class FailAwareWeightedRouting {
+
+    public static final FailAwareWeightedRouting INSTANCE = new FailAwareWeightedRouting();
+    private static final Logger logger = LogManager.getLogger(FailAwareWeightedRouting.class);
+
+    private final static List<RestStatus> internalErrorRestStatusList = List.of(
+        RestStatus.INTERNAL_SERVER_ERROR,
+        RestStatus.BAD_GATEWAY,
+        RestStatus.SERVICE_UNAVAILABLE,
+        RestStatus.GATEWAY_TIMEOUT
+    );
+
+    public static FailAwareWeightedRouting getInstance() {
+        return INSTANCE;
+    }
+
+    /**
+     * *
+     * @return true if exception is due to cluster availability issues
+     */
+    private boolean isInternalFailure(Exception exception) {
+        if (exception instanceof OpenSearchException) {
+            // checking for 5xx failures
+            return internalErrorRestStatusList.contains(((OpenSearchException) exception).status());
+        }
+        return false;
+    }
+
+    /**
+     * This function returns next shard copy to retry search request in case of failure from previous copy returned
+     * by the iterator. It has the logic to fail open ie request shard copies present in nodes with weighted shard
+     * routing weight set to zero
+     *
+     * @param shardIt Shard Iterator containing order in which shard copies for a shard need to be requested
+     * @param clusterState The current cluster state
+     * @param exception The underlying search exception
+     * @param onShardSkipped The runnable to execute once a shard is skipped
+     * @return the next shard copy
+     */
+    public SearchShardTarget findNext(
+        final SearchShardIterator shardIt,
+        ClusterState clusterState,
+        Exception exception,
+        Runnable onShardSkipped
+    ) {
+        SearchShardTarget next = shardIt.nextOrNull();
+        if (ignoreWeightedRouting(clusterState)) {
+            return next;
+        }
+
+        while (next != null && WeightedRoutingUtils.isWeighedAway(next.getNodeId(), clusterState)) {
+            SearchShardTarget nextShard = next;
+            if (canFailOpen(nextShard.getShardId(), shardIt.size(), exception, clusterState)) {
+                logger.info(() -> new ParameterizedMessage("{}: Fail open executed due to exception", nextShard.getShardId()), exception);
+                getWeightedRoutingStats().updateFailOpenCount();
+                break;
+            }
+            next = shardIt.nextOrNull();
+            onShardSkipped.run();
+        }
+        return next;
+    }
+
+    /**
+     * This function returns next shard copy to retry search request in case of failure from previous copy returned
+     * by the iterator. It has the logic to fail open ie request shard copies present in nodes with weighted shard
+     * routing weight set to zero
+     *
+     * @param shardsIt Shard Iterator containing order in which shard copies for a shard need to be requested
+     * @param clusterState The current cluster state
+     * @param exception The underlying search exception
+     * @param onShardSkipped The runnable to execute once a shard is skipped
+     * @return the next shard copy
+     */
+    public ShardRouting findNext(final ShardsIterator shardsIt, ClusterState clusterState, Exception exception, Runnable onShardSkipped) {
+        ShardRouting next = shardsIt.nextOrNull();
+        if (ignoreWeightedRouting(clusterState)) {
+            return next;
+        }
+
+        while (next != null && WeightedRoutingUtils.isWeighedAway(next.currentNodeId(), clusterState)) {
+            ShardRouting nextShard = next;
+            if (canFailOpen(nextShard.shardId(), shardsIt.size(), exception, clusterState)) {
+                logger.info(() -> new ParameterizedMessage("{}: Fail open executed due to exception", nextShard.shardId()), exception);
+                getWeightedRoutingStats().updateFailOpenCount();
+                break;
+            }
+            next = shardsIt.nextOrNull();
+            onShardSkipped.run();
+        }
+        return next;
+    }
+
+    /**
+     * *
+     * @return true if can fail open ie request shard copies present in nodes with weighted shard
+     * routing weight set to zero
+     */
+    private boolean canFailOpen(ShardId shardId, int shardItSize, Exception exception, ClusterState clusterState) {
+        return shardItSize == 1 || isInternalFailure(exception) || hasInActiveShardCopies(clusterState, shardId);
+    }
+
+    private boolean hasInActiveShardCopies(ClusterState clusterState, ShardId shardId) {
+        List<ShardRouting> shards = clusterState.routingTable().shardRoutingTable(shardId).shards();
+        for (ShardRouting shardRouting : shards) {
+            if (!shardRouting.active()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private boolean ignoreWeightedRouting(ClusterState clusterState) {
+        return IGNORE_WEIGHTED_SHARD_ROUTING.get(clusterState.getMetadata().settings());
+    }
+
+    public WeightedRoutingStats getWeightedRoutingStats() {
+        return WeightedRoutingStats.getInstance();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/GroupShardsIterator.java b/server/src/main/java/org/opensearch/cluster/routing/GroupShardsIterator.java
index 17847be0a0bd2..8e9371e6a714c 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/GroupShardsIterator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/GroupShardsIterator.java
@@ -43,6 +43,8 @@
  * iterated by this {@link Iterable} represents a group of shards.
  * ShardsIterators are always returned in ascending order independently of their order at construction
  * time. The incoming iterators are sorted to ensure consistent iteration behavior across Nodes / JVMs.
+ *
+ * @opensearch.internal
 */
 public final class GroupShardsIterator<ShardIt extends Comparable<ShardIt> & Countable> implements Iterable<ShardIt> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/IllegalShardRoutingStateException.java b/server/src/main/java/org/opensearch/cluster/routing/IllegalShardRoutingStateException.java
index 94b8b0f3628be..27acbcde04d62 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/IllegalShardRoutingStateException.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/IllegalShardRoutingStateException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * This exception defines illegal states of shard routing
+ *
+ * @opensearch.internal
  */
 public class IllegalShardRoutingStateException extends RoutingException {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/IndexRoutingTable.java b/server/src/main/java/org/opensearch/cluster/routing/IndexRoutingTable.java
index 99d71de9fe16b..b12698c8a320e 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/IndexRoutingTable.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/IndexRoutingTable.java
@@ -32,9 +32,6 @@
 
 package org.opensearch.cluster.routing;
 
-import com.carrotsearch.hppc.IntSet;
-import com.carrotsearch.hppc.cursors.IntCursor;
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
@@ -44,20 +41,22 @@
 import org.opensearch.cluster.routing.RecoverySource.ExistingStoreRecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.LocalShardsRecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.PeerRecoverySource;
+import org.opensearch.cluster.routing.RecoverySource.RemoteStoreRecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
 
@@ -75,6 +74,8 @@
  * reflected in the routing table or in related classes, replicas are
  * represented as {@link ShardRouting}.
  * </p>
+ *
+ * @opensearch.internal
  */
 public class IndexRoutingTable extends AbstractDiffable<IndexRoutingTable> implements Iterable<IndexShardRoutingTable> {
 
@@ -83,17 +84,17 @@ public class IndexRoutingTable extends AbstractDiffable<IndexRoutingTable> imple
 
     // note, we assume that when the index routing is created, ShardRoutings are created for all possible number of
     // shards with state set to UNASSIGNED
-    private final ImmutableOpenIntMap<IndexShardRoutingTable> shards;
+    private final Map<Integer, IndexShardRoutingTable> shards;
 
     private final List<ShardRouting> allActiveShards;
 
-    IndexRoutingTable(Index index, ImmutableOpenIntMap<IndexShardRoutingTable> shards) {
+    IndexRoutingTable(Index index, final Map<Integer, IndexShardRoutingTable> shards) {
         this.index = index;
         this.shuffler = new RotationShardShuffler(Randomness.get().nextInt());
-        this.shards = shards;
+        this.shards = Collections.unmodifiableMap(shards);
         List<ShardRouting> allActiveShards = new ArrayList<>();
-        for (IntObjectCursor<IndexShardRoutingTable> cursor : shards) {
-            for (ShardRouting shardRouting : cursor.value) {
+        for (IndexShardRoutingTable cursor : shards.values()) {
+            for (ShardRouting shardRouting : cursor) {
                 if (shardRouting.active()) {
                     allActiveShards.add(shardRouting);
                 }
@@ -194,7 +195,7 @@ boolean validate(Metadata metadata) {
 
     @Override
     public Iterator<IndexShardRoutingTable> iterator() {
-        return shards.valuesIt();
+        return shards.values().iterator();
     }
 
     /**
@@ -229,11 +230,11 @@ public int numberOfNodesShardsAreAllocatedOn(String... excludedNodes) {
         return nodes.size();
     }
 
-    public ImmutableOpenIntMap<IndexShardRoutingTable> shards() {
+    public Map<Integer, IndexShardRoutingTable> shards() {
         return shards;
     }
 
-    public ImmutableOpenIntMap<IndexShardRoutingTable> getShards() {
+    public Map<Integer, IndexShardRoutingTable> getShards() {
         return shards();
     }
 
@@ -363,10 +364,15 @@ public static Builder builder(Index index) {
         return new Builder(index);
     }
 
+    /**
+     * Builder of a routing table.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final Index index;
-        private final ImmutableOpenIntMap.Builder<IndexShardRoutingTable> shards = ImmutableOpenIntMap.builder();
+        private final Map<Integer, IndexShardRoutingTable> shards = new HashMap<>();
 
         public Builder(Index index) {
             this.index = index;
@@ -410,7 +416,11 @@ public Builder initializeAsFromOpenToClose(IndexMetadata indexMetadata) {
         /**
          * Initializes a new empty index, to be restored from a snapshot
          */
-        public Builder initializeAsNewRestore(IndexMetadata indexMetadata, SnapshotRecoverySource recoverySource, IntSet ignoreShards) {
+        public Builder initializeAsNewRestore(
+            IndexMetadata indexMetadata,
+            SnapshotRecoverySource recoverySource,
+            final Set<Integer> ignoreShards
+        ) {
             final UnassignedInfo unassignedInfo = new UnassignedInfo(
                 UnassignedInfo.Reason.NEW_INDEX_RESTORED,
                 "restore_source["
@@ -437,13 +447,65 @@ public Builder initializeAsRestore(IndexMetadata indexMetadata, SnapshotRecovery
             return initializeAsRestore(indexMetadata, recoverySource, null, false, unassignedInfo);
         }
 
+        /**
+         * Initializes an existing index, to be restored from remote store
+         */
+        public Builder initializeAsRemoteStoreRestore(
+            IndexMetadata indexMetadata,
+            RemoteStoreRecoverySource recoverySource,
+            Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap,
+            boolean forceRecoverAllPrimaries
+        ) {
+            final UnassignedInfo unassignedInfo = new UnassignedInfo(
+                UnassignedInfo.Reason.EXISTING_INDEX_RESTORED,
+                "restore_source[remote_store]"
+            );
+            assert indexMetadata.getIndex().equals(index);
+            if (shards.isEmpty() == false) {
+                throw new IllegalStateException("trying to initialize an index with fresh shards, but already has shards created");
+            }
+            for (int shardNumber = 0; shardNumber < indexMetadata.getNumberOfShards(); shardNumber++) {
+                ShardId shardId = new ShardId(index, shardNumber);
+                if (forceRecoverAllPrimaries == false && indexShardRoutingTableMap.containsKey(shardId) == false) {
+                    throw new IllegalStateException("IndexShardRoutingTable is not present for shardId: " + shardId);
+                }
+                IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+                IndexShardRoutingTable indexShardRoutingTable = indexShardRoutingTableMap.get(shardId);
+                if (forceRecoverAllPrimaries || indexShardRoutingTable == null || indexShardRoutingTable.primaryShard().unassigned()) {
+                    // Primary shard to be recovered from remote store.
+                    indexShardRoutingBuilder.addShard(ShardRouting.newUnassigned(shardId, true, recoverySource, unassignedInfo));
+                    // All the replica shards to be recovered from peer recovery.
+                    for (int replicaNumber = 0; replicaNumber < indexMetadata.getNumberOfReplicas(); replicaNumber++) {
+                        indexShardRoutingBuilder.addShard(
+                            ShardRouting.newUnassigned(shardId, false, PeerRecoverySource.INSTANCE, unassignedInfo)
+                        );
+                    }
+                } else {
+                    // Primary is either active or initializing. Do not trigger restore.
+                    indexShardRoutingBuilder.addShard(indexShardRoutingTable.primaryShard());
+                    // Replica, if unassigned, trigger peer recovery else no action.
+                    for (ShardRouting shardRouting : indexShardRoutingTable.replicaShards()) {
+                        if (shardRouting.unassigned()) {
+                            indexShardRoutingBuilder.addShard(
+                                ShardRouting.newUnassigned(shardId, false, PeerRecoverySource.INSTANCE, unassignedInfo)
+                            );
+                        } else {
+                            indexShardRoutingBuilder.addShard(shardRouting);
+                        }
+                    }
+                }
+                shards.put(shardNumber, indexShardRoutingBuilder.build());
+            }
+            return this;
+        }
+
         /**
          * Initializes an index, to be restored from snapshot
          */
         private Builder initializeAsRestore(
             IndexMetadata indexMetadata,
-            SnapshotRecoverySource recoverySource,
-            IntSet ignoreShards,
+            RecoverySource recoverySource,
+            final Set<Integer> ignoreShards,
             boolean asNew,
             UnassignedInfo unassignedInfo
         ) {
@@ -521,8 +583,7 @@ private Builder initializeEmpty(IndexMetadata indexMetadata, UnassignedInfo unas
         }
 
         public Builder addReplica() {
-            for (IntCursor cursor : shards.keys()) {
-                int shardNumber = cursor.value;
+            for (final int shardNumber : shards.keySet()) {
                 ShardId shardId = new ShardId(index, shardNumber);
                 // version 0, will get updated when reroute will happen
                 ShardRouting shard = ShardRouting.newUnassigned(
@@ -537,8 +598,7 @@ public Builder addReplica() {
         }
 
         public Builder removeReplica() {
-            for (IntCursor cursor : shards.keys()) {
-                int shardId = cursor.value;
+            for (final int shardId : shards.keySet()) {
                 IndexShardRoutingTable indexShard = shards.get(shardId);
                 if (indexShard.replicaShards().isEmpty()) {
                     // nothing to do here!
@@ -592,7 +652,7 @@ public Builder addShard(ShardRouting shard) {
         }
 
         public IndexRoutingTable build() {
-            return new IndexRoutingTable(index, shards.build());
+            return new IndexRoutingTable(index, shards);
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/IndexShardRoutingTable.java b/server/src/main/java/org/opensearch/cluster/routing/IndexShardRoutingTable.java
index 8ddcf9fd7f1bb..9cc09c6e4c31c 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/IndexShardRoutingTable.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/IndexShardRoutingTable.java
@@ -32,16 +32,19 @@
 
 package org.opensearch.cluster.routing;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.collect.MapBuilder;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.node.ResponseCollectorService;
 
 import java.io.IOException;
@@ -51,12 +54,15 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import static java.util.Collections.emptyMap;
 
@@ -66,10 +72,14 @@
  * a disjoint set of the index data and each shard has one or more instances
  * referred to as replicas of a shard. Given that, this class encapsulates all
  * replicas (instances) for a single index shard.
+ *
+ * @opensearch.internal
  */
 public class IndexShardRoutingTable implements Iterable<ShardRouting> {
 
     final ShardShuffler shuffler;
+    // Shuffler for weighted round-robin shard routing. This uses rotation to permute shards.
+    final ShardShuffler shufflerForWeightedRouting;
     final ShardId shardId;
 
     final ShardRouting primary;
@@ -83,6 +93,11 @@ public class IndexShardRoutingTable implements Iterable<ShardRouting> {
     private volatile Map<AttributesKey, AttributesRoutings> activeShardsByAttributes = emptyMap();
     private volatile Map<AttributesKey, AttributesRoutings> initializingShardsByAttributes = emptyMap();
     private final Object shardsByAttributeMutex = new Object();
+    private final Object shardsByWeightMutex = new Object();
+    private volatile Map<WeightedRoutingKey, List<ShardRouting>> activeShardsByWeight = emptyMap();
+    private volatile Map<WeightedRoutingKey, List<ShardRouting>> initializingShardsByWeight = emptyMap();
+
+    private static final Logger logger = LogManager.getLogger(IndexShardRoutingTable.class);
 
     /**
      * The initializing list, including ones that are initializing on a target node because of relocation.
@@ -93,6 +108,7 @@ public class IndexShardRoutingTable implements Iterable<ShardRouting> {
     IndexShardRoutingTable(ShardId shardId, List<ShardRouting> shards) {
         this.shardId = shardId;
         this.shuffler = new RotationShardShuffler(Randomness.get().nextInt());
+        this.shufflerForWeightedRouting = new RotationShardShuffler(Randomness.get().nextInt());
         this.shards = Collections.unmodifiableList(shards);
 
         ShardRouting primary = null;
@@ -231,6 +247,10 @@ public List<ShardRouting> assignedShards() {
         return this.assignedShards;
     }
 
+    public Map<WeightedRoutingKey, List<ShardRouting>> getActiveShardsByWeight() {
+        return activeShardsByWeight;
+    }
+
     public ShardIterator shardsRandomIt() {
         return new PlainShardIterator(shardId, shuffler.shuffle(shards));
     }
@@ -290,6 +310,118 @@ public ShardIterator activeInitializingShardsRankedIt(
         return new PlainShardIterator(shardId, ordered);
     }
 
+    /**
+     * Returns an iterator over active and initializing shards, shards are ordered by weighted
+     * round-robin scheduling policy.
+     *
+     * @param weightedRouting entity
+     * @param nodes           discovered nodes in the cluster
+     * @param isFailOpenEnabled if true, shards search requests in case of failures are tried on shard copies present
+     *                          in node attribute value with weight zero
+     * @return an iterator over active and initializing shards, ordered by weighted round-robin
+     * scheduling policy. Making sure that initializing shards are the last to iterate through.
+     */
+    public ShardIterator activeInitializingShardsWeightedIt(
+        WeightedRouting weightedRouting,
+        DiscoveryNodes nodes,
+        double defaultWeight,
+        boolean isFailOpenEnabled,
+        @Nullable Integer seed
+    ) {
+        if (seed == null) {
+            seed = shufflerForWeightedRouting.nextSeed();
+        }
+        List<ShardRouting> ordered = activeInitializingShardsWithWeights(weightedRouting, nodes, defaultWeight, seed);
+
+        // append shards for attribute value with weight zero, so that shard search requests can be tried on
+        // shard copies in case of request failure from other attribute values.
+        if (isFailOpenEnabled) {
+            try {
+                Stream<String> keys = weightedRouting.weights()
+                    .entrySet()
+                    .stream()
+                    .filter(entry -> entry.getValue().intValue() == WeightedRoutingMetadata.WEIGHED_AWAY_WEIGHT)
+                    .map(Map.Entry::getKey);
+                keys.forEach(key -> {
+                    ShardIterator iterator = onlyNodeSelectorActiveInitializingShardsIt(weightedRouting.attributeName() + ":" + key, nodes);
+                    while (iterator.remaining() > 0) {
+                        ordered.add(iterator.nextOrNull());
+                    }
+                });
+            } catch (IllegalArgumentException e) {
+                // this exception is thrown by {@link onlyNodeSelectorActiveInitializingShardsIt} in case count of shard
+                // copies found is zero
+                logger.debug("no shard copies found for shard id [{}] for node attribute with weight zero", shardId);
+            }
+        }
+
+        return new PlainShardIterator(shardId, ordered);
+    }
+
+    private List<ShardRouting> activeInitializingShardsWithWeights(
+        WeightedRouting weightedRouting,
+        DiscoveryNodes nodes,
+        double defaultWeight,
+        int seed
+    ) {
+        List<ShardRouting> ordered = new ArrayList<>();
+        List<ShardRouting> orderedActiveShards = getActiveShardsByWeight(weightedRouting, nodes, defaultWeight);
+        ordered.addAll(shufflerForWeightedRouting.shuffle(orderedActiveShards, seed));
+        if (!allInitializingShards.isEmpty()) {
+            List<ShardRouting> orderedInitializingShards = getInitializingShardsByWeight(weightedRouting, nodes, defaultWeight);
+            ordered.addAll(orderedInitializingShards);
+        }
+        List<ShardRouting> orderedListWithDistinctShards;
+        orderedListWithDistinctShards = ordered.stream().distinct().collect(Collectors.toList());
+        return orderedListWithDistinctShards;
+    }
+
+    /**
+     * Returns a list containing shard routings ordered using weighted round-robin scheduling.
+     */
+    private List<ShardRouting> shardsOrderedByWeight(
+        List<ShardRouting> shards,
+        WeightedRouting weightedRouting,
+        DiscoveryNodes nodes,
+        double defaultWeight
+    ) {
+        WeightedRoundRobin<ShardRouting> weightedRoundRobin = new WeightedRoundRobin<>(
+            calculateShardWeight(shards, weightedRouting, nodes, defaultWeight)
+        );
+        List<WeightedRoundRobin.Entity<ShardRouting>> shardsOrderedbyWeight = weightedRoundRobin.orderEntities();
+        List<ShardRouting> orderedShardRouting = new ArrayList<>(activeShards.size());
+        if (shardsOrderedbyWeight != null) {
+            for (WeightedRoundRobin.Entity<ShardRouting> shardRouting : shardsOrderedbyWeight) {
+                orderedShardRouting.add(shardRouting.getTarget());
+            }
+        }
+        return orderedShardRouting;
+    }
+
+    /**
+     * Returns a list containing shard routing and associated weight. This function iterates through all the shards and
+     * uses weighted routing to find weight for the corresponding shard. This is fed to weighted round-robin scheduling
+     * to order shards by weight.
+     */
+    private List<WeightedRoundRobin.Entity<ShardRouting>> calculateShardWeight(
+        List<ShardRouting> shards,
+        WeightedRouting weightedRouting,
+        DiscoveryNodes nodes,
+        double defaultWeight
+    ) {
+        List<WeightedRoundRobin.Entity<ShardRouting>> shardsWithWeights = new ArrayList<>();
+        for (ShardRouting shard : shards) {
+            DiscoveryNode node = nodes.get(shard.currentNodeId());
+            if (node != null) {
+                String attVal = node.getAttributes().get(weightedRouting.attributeName());
+                // If weight for a zone is not defined, considering it as 1 by default
+                Double weight = weightedRouting.weights().getOrDefault(attVal, defaultWeight);
+                shardsWithWeights.add(new WeightedRoundRobin.Entity<>(weight, shard));
+            }
+        }
+        return shardsWithWeights;
+    }
+
     private static Set<String> getAllNodeIds(final List<ShardRouting> shards) {
         final Set<String> nodeIds = new HashSet<>();
         for (ShardRouting shard : shards) {
@@ -443,6 +575,96 @@ public ShardIterator primaryShardIt() {
         return new PlainShardIterator(shardId, Collections.emptyList());
     }
 
+    /**
+     * Returns true if no primaries are active or initializing for this shard
+     */
+    private boolean noPrimariesActive() {
+        return this.primary != null && !this.primary.active() && !this.primary.initializing();
+    }
+
+    /**
+     * Returns an iterator only on the active primary shard.
+     */
+    public ShardIterator primaryActiveInitializingShardIt() {
+        if (noPrimariesActive()) {
+            return new PlainShardIterator(shardId, Collections.emptyList());
+        }
+        return primaryShardIt();
+    }
+
+    /**
+     * Returns an ordered iterator on the active primary shard, followed by replica shards.
+     */
+    public ShardIterator primaryFirstActiveInitializingShardsIt() {
+        ArrayList<ShardRouting> ordered = new ArrayList<>(activeShards.size() + allInitializingShards.size());
+        // fill it in a randomized fashion
+        for (ShardRouting shardRouting : shuffler.shuffle(activeShards)) {
+            ordered.add(shardRouting);
+            if (shardRouting.primary()) {
+                // switch, its the matching node id
+                ordered.set(ordered.size() - 1, ordered.get(0));
+                ordered.set(0, shardRouting);
+            }
+        }
+        // no need to worry about primary first here..., its temporal
+        if (!allInitializingShards.isEmpty()) {
+            ordered.addAll(allInitializingShards);
+        }
+        return new PlainShardIterator(shardId, ordered);
+    }
+
+    /**
+     * Returns an iterator on replica shards.
+     */
+    public ShardIterator replicaActiveInitializingShardIt() {
+        // If the primaries are unassigned, return an empty list (there aren't
+        // any replicas to query anyway)
+        if (noPrimariesActive()) {
+            return new PlainShardIterator(shardId, Collections.emptyList());
+        }
+
+        LinkedList<ShardRouting> ordered = new LinkedList<>();
+        for (ShardRouting replica : shuffler.shuffle(replicas)) {
+            if (replica.active()) {
+                ordered.addFirst(replica);
+            } else if (replica.initializing()) {
+                ordered.addLast(replica);
+            }
+        }
+        return new PlainShardIterator(shardId, ordered);
+    }
+
+    /**
+     * Returns an ordered iterator on active replica shards, followed by the primary shard.
+     */
+    public ShardIterator replicaFirstActiveInitializingShardsIt() {
+        // If the primaries are unassigned, return an empty list (there aren't
+        // any replicas to query anyway)
+        if (noPrimariesActive()) {
+            return new PlainShardIterator(shardId, Collections.emptyList());
+        }
+
+        ArrayList<ShardRouting> ordered = new ArrayList<>(activeShards.size() + allInitializingShards.size());
+        // fill it in a randomized fashion with the active replicas
+        for (ShardRouting replica : shuffler.shuffle(replicas)) {
+            if (replica.active()) {
+                ordered.add(replica);
+            }
+        }
+
+        // Add the primary shard
+        ordered.add(primary);
+
+        // Add initializing shards last
+        if (!allInitializingShards.isEmpty()) {
+            ordered.addAll(allInitializingShards);
+        }
+        return new PlainShardIterator(shardId, ordered);
+    }
+
+    /**
+     * Returns an iterator on active and initializing shards residing on the provided nodeId.
+     */
     public ShardIterator onlyNodeActiveInitializingShardsIt(String nodeId) {
         ArrayList<ShardRouting> ordered = new ArrayList<>(activeShards.size() + allInitializingShards.size());
         int seed = shuffler.nextSeed();
@@ -696,6 +918,71 @@ public int shardsMatchingPredicateCount(Predicate<ShardRouting> predicate) {
         return count;
     }
 
+    /**
+     * Key for WeightedRouting Shard Iterator
+     *
+     * @opensearch.internal
+     */
+    public static class WeightedRoutingKey {
+        private final WeightedRouting weightedRouting;
+
+        public WeightedRoutingKey(WeightedRouting weightedRouting) {
+            this.weightedRouting = weightedRouting;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            WeightedRoutingKey key = (WeightedRoutingKey) o;
+            if (!weightedRouting.equals(key.weightedRouting)) return false;
+            return true;
+        }
+
+        @Override
+        public int hashCode() {
+            int result = weightedRouting.hashCode();
+            return result;
+        }
+    }
+
+    /**
+     * *
+     * Gets active shard routing from memory if available, else calculates and put it in memory.
+     */
+    private List<ShardRouting> getActiveShardsByWeight(WeightedRouting weightedRouting, DiscoveryNodes nodes, double defaultWeight) {
+        WeightedRoutingKey key = new WeightedRoutingKey(weightedRouting);
+        List<ShardRouting> shardRoutings = activeShardsByWeight.get(key);
+        if (shardRoutings == null) {
+            synchronized (shardsByWeightMutex) {
+                shardRoutings = shardsOrderedByWeight(activeShards, weightedRouting, nodes, defaultWeight);
+                activeShardsByWeight = new MapBuilder().put(key, shardRoutings).immutableMap();
+            }
+        }
+        return shardRoutings;
+    }
+
+    /**
+     * *
+     * Gets initializing shard routing from memory if available, else calculates and put it in memory.
+     */
+    private List<ShardRouting> getInitializingShardsByWeight(WeightedRouting weightedRouting, DiscoveryNodes nodes, double defaultWeight) {
+        WeightedRoutingKey key = new WeightedRoutingKey(weightedRouting);
+        List<ShardRouting> shardRoutings = initializingShardsByWeight.get(key);
+        if (shardRoutings == null) {
+            synchronized (shardsByWeightMutex) {
+                shardRoutings = shardsOrderedByWeight(activeShards, weightedRouting, nodes, defaultWeight);
+                initializingShardsByWeight = new MapBuilder().put(key, shardRoutings).immutableMap();
+            }
+        }
+        return shardRoutings;
+    }
+
+    /**
+     * Builder of an index shard routing table.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/Murmur3HashFunction.java b/server/src/main/java/org/opensearch/cluster/routing/Murmur3HashFunction.java
index 2b1b184cb4e74..ff60aa752ee67 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/Murmur3HashFunction.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/Murmur3HashFunction.java
@@ -36,6 +36,8 @@
 
 /**
  * Hash function based on the Murmur3 algorithm, which is the default for OpenSearch.
+ *
+ * @opensearch.internal
  */
 public final class Murmur3HashFunction {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/NodeWeighedAwayException.java b/server/src/main/java/org/opensearch/cluster/routing/NodeWeighedAwayException.java
new file mode 100644
index 0000000000000..4fc0da07ff447
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/NodeWeighedAwayException.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown if the node is weighed away by @{@link WeightedRoutingService}
+ *
+ * @opensearch.internal
+ */
+public class NodeWeighedAwayException extends OpenSearchException {
+
+    public NodeWeighedAwayException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public NodeWeighedAwayException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.MISDIRECTED_REQUEST;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/OperationRouting.java b/server/src/main/java/org/opensearch/cluster/routing/OperationRouting.java
index 6d4db7a6513b9..0cf48b38f267e 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/OperationRouting.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/OperationRouting.java
@@ -34,15 +34,17 @@
 
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.ResponseCollectorService;
 
 import java.util.ArrayList;
@@ -54,6 +56,11 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * Routes cluster operations
+ *
+ * @opensearch.internal
+ */
 public class OperationRouting {
 
     public static final Setting<Boolean> USE_ADAPTIVE_REPLICA_SELECTION_SETTING = Setting.boolSetting(
@@ -70,9 +77,47 @@ public class OperationRouting {
         Setting.Property.Dynamic,
         Setting.Property.NodeScope
     );
+    public static final Setting<Double> WEIGHTED_ROUTING_DEFAULT_WEIGHT = Setting.doubleSetting(
+        "cluster.routing.weighted.default_weight",
+        1.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Boolean> WEIGHTED_ROUTING_FAILOPEN_ENABLED = Setting.boolSetting(
+        "cluster.routing.weighted.fail_open",
+        true,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Boolean> STRICT_WEIGHTED_SHARD_ROUTING_ENABLED = Setting.boolSetting(
+        "cluster.routing.weighted.strict",
+        true,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Boolean> IGNORE_WEIGHTED_SHARD_ROUTING = Setting.boolSetting(
+        "cluster.routing.ignore_weighted_routing",
+        false,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private static final List<Preference> WEIGHTED_ROUTING_RESTRICTED_PREFERENCES = Arrays.asList(
+        Preference.ONLY_NODES,
+        Preference.PREFER_NODES
+    );
+
     private volatile List<String> awarenessAttributes;
     private volatile boolean useAdaptiveReplicaSelection;
     private volatile boolean ignoreAwarenessAttr;
+    private volatile double weightedRoutingDefaultWeight;
+    private volatile boolean isFailOpenEnabled;
+    private volatile boolean isStrictWeightedShardRouting;
+    private volatile boolean ignoreWeightedRouting;
 
     public OperationRouting(Settings settings, ClusterSettings clusterSettings) {
         // whether to ignore awareness attributes when routing requests
@@ -83,8 +128,16 @@ public OperationRouting(Settings settings, ClusterSettings clusterSettings) {
             this::setAwarenessAttributes
         );
         this.useAdaptiveReplicaSelection = USE_ADAPTIVE_REPLICA_SELECTION_SETTING.get(settings);
+        this.weightedRoutingDefaultWeight = WEIGHTED_ROUTING_DEFAULT_WEIGHT.get(settings);
+        this.isFailOpenEnabled = WEIGHTED_ROUTING_FAILOPEN_ENABLED.get(settings);
+        this.isStrictWeightedShardRouting = STRICT_WEIGHTED_SHARD_ROUTING_ENABLED.get(settings);
+        this.ignoreWeightedRouting = IGNORE_WEIGHTED_SHARD_ROUTING.get(settings);
         clusterSettings.addSettingsUpdateConsumer(USE_ADAPTIVE_REPLICA_SELECTION_SETTING, this::setUseAdaptiveReplicaSelection);
         clusterSettings.addSettingsUpdateConsumer(IGNORE_AWARENESS_ATTRIBUTES_SETTING, this::setIgnoreAwarenessAttributes);
+        clusterSettings.addSettingsUpdateConsumer(WEIGHTED_ROUTING_DEFAULT_WEIGHT, this::setWeightedRoutingDefaultWeight);
+        clusterSettings.addSettingsUpdateConsumer(WEIGHTED_ROUTING_FAILOPEN_ENABLED, this::setFailOpenEnabled);
+        clusterSettings.addSettingsUpdateConsumer(STRICT_WEIGHTED_SHARD_ROUTING_ENABLED, this::setStrictWeightedShardRouting);
+        clusterSettings.addSettingsUpdateConsumer(IGNORE_WEIGHTED_SHARD_ROUTING, this::setIgnoreWeightedRouting);
     }
 
     void setUseAdaptiveReplicaSelection(boolean useAdaptiveReplicaSelection) {
@@ -95,6 +148,22 @@ void setIgnoreAwarenessAttributes(boolean ignoreAwarenessAttributes) {
         this.ignoreAwarenessAttr = ignoreAwarenessAttributes;
     }
 
+    void setWeightedRoutingDefaultWeight(double weightedRoutingDefaultWeight) {
+        this.weightedRoutingDefaultWeight = weightedRoutingDefaultWeight;
+    }
+
+    void setFailOpenEnabled(boolean isFailOpenEnabled) {
+        this.isFailOpenEnabled = isFailOpenEnabled;
+    }
+
+    void setStrictWeightedShardRouting(boolean strictWeightedShardRouting) {
+        this.isStrictWeightedShardRouting = strictWeightedShardRouting;
+    }
+
+    void setIgnoreWeightedRouting(boolean isWeightedRoundRobinEnabled) {
+        this.ignoreWeightedRouting = isWeightedRoundRobinEnabled;
+    }
+
     public boolean isIgnoreAwarenessAttr() {
         return ignoreAwarenessAttr;
     }
@@ -111,6 +180,10 @@ public boolean ignoreAwarenessAttributes() {
         return this.awarenessAttributes.isEmpty() || this.ignoreAwarenessAttr;
     }
 
+    public double getWeightedRoutingDefaultWeight() {
+        return this.weightedRoutingDefaultWeight;
+    }
+
     public ShardIterator indexShards(ClusterState clusterState, String index, String id, @Nullable String routing) {
         return shards(clusterState, index, id, routing).shardsIt();
     }
@@ -128,7 +201,8 @@ public ShardIterator getShards(
             clusterState.nodes(),
             preference,
             null,
-            null
+            null,
+            clusterState.getMetadata().weightedRoutingMetadata()
         );
     }
 
@@ -140,7 +214,8 @@ public ShardIterator getShards(ClusterState clusterState, String index, int shar
             clusterState.nodes(),
             preference,
             null,
-            null
+            null,
+            clusterState.metadata().weightedRoutingMetadata()
         );
     }
 
@@ -164,13 +239,21 @@ public GroupShardsIterator<ShardIterator> searchShards(
         final Set<IndexShardRoutingTable> shards = computeTargetedShards(clusterState, concreteIndices, routing);
         final Set<ShardIterator> set = new HashSet<>(shards.size());
         for (IndexShardRoutingTable shard : shards) {
+            IndexMetadata indexMetadataForShard = indexMetadata(clusterState, shard.shardId.getIndex().getName());
+            if (IndexModule.Type.REMOTE_SNAPSHOT.match(
+                indexMetadataForShard.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey())
+            ) && (preference == null || preference.isEmpty())) {
+                preference = Preference.PRIMARY.type();
+            }
+
             ShardIterator iterator = preferenceActiveShardIterator(
                 shard,
                 clusterState.nodes().getLocalNodeId(),
                 clusterState.nodes(),
                 preference,
                 collectorService,
-                nodeCounts
+                nodeCounts,
+                clusterState.metadata().weightedRoutingMetadata()
             );
             if (iterator != null) {
                 set.add(iterator);
@@ -220,10 +303,11 @@ private ShardIterator preferenceActiveShardIterator(
         DiscoveryNodes nodes,
         @Nullable String preference,
         @Nullable ResponseCollectorService collectorService,
-        @Nullable Map<String, Long> nodeCounts
+        @Nullable Map<String, Long> nodeCounts,
+        @Nullable WeightedRoutingMetadata weightedRoutingMetadata
     ) {
         if (preference == null || preference.isEmpty()) {
-            return shardRoutings(indexShard, nodes, collectorService, nodeCounts);
+            return shardRoutings(indexShard, nodes, collectorService, nodeCounts, weightedRoutingMetadata);
         }
         if (preference.charAt(0) == '_') {
             Preference preferenceType = Preference.parse(preference);
@@ -250,13 +334,14 @@ private ShardIterator preferenceActiveShardIterator(
                 }
                 // no more preference
                 if (index == -1 || index == preference.length() - 1) {
-                    return shardRoutings(indexShard, nodes, collectorService, nodeCounts);
+                    return shardRoutings(indexShard, nodes, collectorService, nodeCounts, weightedRoutingMetadata);
                 } else {
                     // update the preference and continue
                     preference = preference.substring(index + 1);
                 }
             }
             preferenceType = Preference.parse(preference);
+            checkPreferenceBasedRoutingAllowed(preferenceType, weightedRoutingMetadata);
             switch (preferenceType) {
                 case PREFER_NODES:
                     final Set<String> nodesIds = Arrays.stream(preference.substring(Preference.PREFER_NODES.type().length() + 1).split(","))
@@ -264,6 +349,14 @@ private ShardIterator preferenceActiveShardIterator(
                     return indexShard.preferNodeActiveInitializingShardsIt(nodesIds);
                 case LOCAL:
                     return indexShard.preferNodeActiveInitializingShardsIt(Collections.singleton(localNodeId));
+                case PRIMARY:
+                    return indexShard.primaryActiveInitializingShardIt();
+                case REPLICA:
+                    return indexShard.replicaActiveInitializingShardIt();
+                case PRIMARY_FIRST:
+                    return indexShard.primaryFirstActiveInitializingShardsIt();
+                case REPLICA_FIRST:
+                    return indexShard.replicaFirstActiveInitializingShardsIt();
                 case ONLY_LOCAL:
                     return indexShard.onlyNodeActiveInitializingShardsIt(localNodeId);
                 case ONLY_NODES:
@@ -282,7 +375,19 @@ private ShardIterator preferenceActiveShardIterator(
         // for a different element in the list by also incorporating the
         // shard ID into the hash of the user-supplied preference key.
         routingHash = 31 * routingHash + indexShard.shardId.hashCode();
-        if (ignoreAwarenessAttributes()) {
+        if (WeightedRoutingUtils.shouldPerformStrictWeightedRouting(
+            isStrictWeightedShardRouting,
+            ignoreWeightedRouting,
+            weightedRoutingMetadata
+        )) {
+            return indexShard.activeInitializingShardsWeightedIt(
+                weightedRoutingMetadata.getWeightedRouting(),
+                nodes,
+                getWeightedRoutingDefaultWeight(),
+                isFailOpenEnabled,
+                routingHash
+            );
+        } else if (ignoreAwarenessAttributes()) {
             return indexShard.activeInitializingShardsIt(routingHash);
         } else {
             return indexShard.preferAttributesActiveInitializingShardsIt(awarenessAttributes, nodes, routingHash);
@@ -293,9 +398,18 @@ private ShardIterator shardRoutings(
         IndexShardRoutingTable indexShard,
         DiscoveryNodes nodes,
         @Nullable ResponseCollectorService collectorService,
-        @Nullable Map<String, Long> nodeCounts
+        @Nullable Map<String, Long> nodeCounts,
+        @Nullable WeightedRoutingMetadata weightedRoutingMetadata
     ) {
-        if (ignoreAwarenessAttributes()) {
+        if (WeightedRoutingUtils.shouldPerformWeightedRouting(ignoreWeightedRouting, weightedRoutingMetadata)) {
+            return indexShard.activeInitializingShardsWeightedIt(
+                weightedRoutingMetadata.getWeightedRouting(),
+                nodes,
+                getWeightedRoutingDefaultWeight(),
+                isFailOpenEnabled,
+                null
+            );
+        } else if (ignoreAwarenessAttributes()) {
             if (useAdaptiveReplicaSelection) {
                 return indexShard.activeInitializingShardsRankedIt(collectorService, nodeCounts);
             } else {
@@ -361,4 +475,15 @@ private static int calculateScaledShardId(IndexMetadata indexMetadata, String ef
         return Math.floorMod(hash, indexMetadata.getRoutingNumShards()) / indexMetadata.getRoutingFactor();
     }
 
+    private void checkPreferenceBasedRoutingAllowed(Preference preference, @Nullable WeightedRoutingMetadata weightedRoutingMetadata) {
+        if (WeightedRoutingUtils.shouldPerformStrictWeightedRouting(
+            isStrictWeightedShardRouting,
+            ignoreWeightedRouting,
+            weightedRoutingMetadata
+        ) && WEIGHTED_ROUTING_RESTRICTED_PREFERENCES.contains(preference)) {
+            throw new PreferenceBasedSearchNotAllowedException(
+                "Preference type based routing not allowed with strict weighted shard routing enabled"
+            );
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/PlainShardIterator.java b/server/src/main/java/org/opensearch/cluster/routing/PlainShardIterator.java
index 2ab19941a3d99..b91eb96819676 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/PlainShardIterator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/PlainShardIterator.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.List;
 
 /**
  * The {@link PlainShardIterator} is a {@link ShardsIterator} which iterates all
  * shards or a given {@link ShardId shard id}
+ *
+ * @opensearch.internal
  */
 public class PlainShardIterator extends PlainShardsIterator implements ShardIterator {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/PlainShardsIterator.java b/server/src/main/java/org/opensearch/cluster/routing/PlainShardsIterator.java
index 8749100d89f23..ebfac411f50bc 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/PlainShardsIterator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/PlainShardsIterator.java
@@ -38,6 +38,8 @@
 /**
  * A simple {@link ShardsIterator} that iterates a list or sub-list of
  * {@link ShardRouting shard indexRoutings}.
+ *
+ * @opensearch.internal
  */
 public class PlainShardsIterator extends PlainIterator<ShardRouting> implements ShardsIterator {
     public PlainShardsIterator(List<ShardRouting> shards) {
diff --git a/server/src/main/java/org/opensearch/cluster/routing/Preference.java b/server/src/main/java/org/opensearch/cluster/routing/Preference.java
index 629de71e94fbb..a1ea01afa118f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/Preference.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/Preference.java
@@ -33,6 +33,8 @@
 
 /**
  * Routing Preference Type
+ *
+ * @opensearch.internal
  */
 public enum Preference {
 
@@ -51,6 +53,26 @@ public enum Preference {
      */
     LOCAL("_local"),
 
+    /**
+     * Route to primary shards
+     */
+    PRIMARY("_primary"),
+
+    /**
+     * Route to replica shards
+     */
+    REPLICA("_replica"),
+
+    /**
+     * Route to primary shards first
+     */
+    PRIMARY_FIRST("_primary_first"),
+
+    /**
+     * Route to replica shards first
+     */
+    REPLICA_FIRST("_replica_first"),
+
     /**
      * Route to the local shard only
      */
@@ -90,6 +112,16 @@ public static Preference parse(String preference) {
                 return PREFER_NODES;
             case "_local":
                 return LOCAL;
+            case "_primary":
+                return PRIMARY;
+            case "_replica":
+                return REPLICA;
+            case "_primary_first":
+            case "_primaryFirst":
+                return PRIMARY_FIRST;
+            case "_replica_first":
+            case "_replicaFirst":
+                return REPLICA_FIRST;
             case "_only_local":
             case "_onlyLocal":
                 return ONLY_LOCAL;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/PreferenceBasedSearchNotAllowedException.java b/server/src/main/java/org/opensearch/cluster/routing/PreferenceBasedSearchNotAllowedException.java
new file mode 100644
index 0000000000000..308520a870389
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/PreferenceBasedSearchNotAllowedException.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * Thrown to disallow preference based search with strict weighted shard routing. See {@link WeightedRoutingService}
+ * * for more details.
+ *
+ * @opensearch.internal
+ */
+public class PreferenceBasedSearchNotAllowedException extends OpenSearchException {
+
+    public PreferenceBasedSearchNotAllowedException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public PreferenceBasedSearchNotAllowedException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.FORBIDDEN;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RecoverySource.java b/server/src/main/java/org/opensearch/cluster/routing/RecoverySource.java
index 543a6cba2e91b..f9c137d0eaf3f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RecoverySource.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RecoverySource.java
@@ -35,12 +35,13 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 
@@ -55,6 +56,8 @@
  * - {@link PeerRecoverySource} recovery from a primary on another node
  * - {@link SnapshotRecoverySource} recovery from a snapshot
  * - {@link LocalShardsRecoverySource} recovery from other shards of another index on the same node
+ *
+ * @opensearch.internal
  */
 public abstract class RecoverySource implements Writeable, ToXContentObject {
 
@@ -86,6 +89,8 @@ public static RecoverySource readFrom(StreamInput in) throws IOException {
                 return new SnapshotRecoverySource(in);
             case LOCAL_SHARDS:
                 return LocalShardsRecoverySource.INSTANCE;
+            case REMOTE_STORE:
+                return new RemoteStoreRecoverySource(in);
             default:
                 throw new IllegalArgumentException("unknown recovery type: " + type.name());
         }
@@ -104,12 +109,18 @@ protected void writeAdditionalFields(StreamOutput out) throws IOException {
 
     }
 
+    /**
+     * Type of recovery.
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         EMPTY_STORE,
         EXISTING_STORE,
         PEER,
         SNAPSHOT,
-        LOCAL_SHARDS
+        LOCAL_SHARDS,
+        REMOTE_STORE
     }
 
     public abstract Type getType();
@@ -139,6 +150,8 @@ public int hashCode() {
 
     /**
      * Recovery from a fresh copy
+     *
+     * @opensearch.internal
      */
     public static final class EmptyStoreRecoverySource extends RecoverySource {
         public static final EmptyStoreRecoverySource INSTANCE = new EmptyStoreRecoverySource();
@@ -156,6 +169,8 @@ public String toString() {
 
     /**
      * Recovery from an existing on-disk store
+     *
+     * @opensearch.internal
      */
     public static final class ExistingStoreRecoverySource extends RecoverySource {
         /**
@@ -209,6 +224,8 @@ public boolean expectEmptyRetentionLeases() {
 
     /**
      * recovery from other shards on same node (shrink index action)
+     *
+     * @opensearch.internal
      */
     public static class LocalShardsRecoverySource extends RecoverySource {
 
@@ -230,6 +247,8 @@ public String toString() {
 
     /**
      * recovery from a snapshot
+     *
+     * @opensearch.internal
      */
     public static class SnapshotRecoverySource extends RecoverySource {
 
@@ -239,23 +258,53 @@ public static class SnapshotRecoverySource extends RecoverySource {
         private final Snapshot snapshot;
         private final IndexId index;
         private final Version version;
+        private final boolean isSearchableSnapshot;
+        private final boolean remoteStoreIndexShallowCopy;
+        private final String sourceRemoteStoreRepository;
 
         public SnapshotRecoverySource(String restoreUUID, Snapshot snapshot, Version version, IndexId indexId) {
+            this(restoreUUID, snapshot, version, indexId, false, false, null);
+        }
+
+        public SnapshotRecoverySource(
+            String restoreUUID,
+            Snapshot snapshot,
+            Version version,
+            IndexId indexId,
+            boolean isSearchableSnapshot,
+            boolean remoteStoreIndexShallowCopy,
+            @Nullable String sourceRemoteStoreRepository
+        ) {
             this.restoreUUID = restoreUUID;
             this.snapshot = Objects.requireNonNull(snapshot);
             this.version = Objects.requireNonNull(version);
             this.index = Objects.requireNonNull(indexId);
+            this.isSearchableSnapshot = isSearchableSnapshot;
+            this.remoteStoreIndexShallowCopy = remoteStoreIndexShallowCopy;
+            this.sourceRemoteStoreRepository = sourceRemoteStoreRepository;
         }
 
         SnapshotRecoverySource(StreamInput in) throws IOException {
             restoreUUID = in.readString();
             snapshot = new Snapshot(in);
-            version = Version.readVersion(in);
+            version = in.readVersion();
             if (in.getVersion().onOrAfter(LegacyESVersion.V_7_7_0)) {
                 index = new IndexId(in);
             } else {
                 index = new IndexId(in.readString(), IndexMetadata.INDEX_UUID_NA_VALUE);
             }
+            if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+                isSearchableSnapshot = in.readBoolean();
+            } else {
+                isSearchableSnapshot = false;
+            }
+            if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+                remoteStoreIndexShallowCopy = in.readBoolean();
+                sourceRemoteStoreRepository = in.readOptionalString();
+            } else {
+                remoteStoreIndexShallowCopy = false;
+                sourceRemoteStoreRepository = null;
+            }
         }
 
         public String restoreUUID() {
@@ -268,7 +317,7 @@ public Snapshot snapshot() {
 
         /**
          * Gets the {@link IndexId} of the recovery source. May contain {@link IndexMetadata#INDEX_UUID_NA_VALUE} as the index uuid if it
-         * was created by an older version master in a mixed version cluster.
+         * was created by an older version cluster-manager in a mixed version cluster.
          *
          * @return IndexId
          */
@@ -280,16 +329,35 @@ public Version version() {
             return version;
         }
 
+        public boolean isSearchableSnapshot() {
+            return isSearchableSnapshot;
+        }
+
+        public String sourceRemoteStoreRepository() {
+            return sourceRemoteStoreRepository;
+        }
+
+        public boolean remoteStoreIndexShallowCopy() {
+            return remoteStoreIndexShallowCopy;
+        }
+
         @Override
         protected void writeAdditionalFields(StreamOutput out) throws IOException {
             out.writeString(restoreUUID);
             snapshot.writeTo(out);
-            Version.writeVersion(version, out);
+            out.writeVersion(version);
             if (out.getVersion().onOrAfter(LegacyESVersion.V_7_7_0)) {
                 index.writeTo(out);
             } else {
                 out.writeString(index.getName());
             }
+            if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+                out.writeBoolean(isSearchableSnapshot);
+            }
+            if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+                out.writeBoolean(remoteStoreIndexShallowCopy);
+                out.writeOptionalString(sourceRemoteStoreRepository);
+            }
         }
 
         @Override
@@ -303,7 +371,10 @@ public void addAdditionalFields(XContentBuilder builder, ToXContent.Params param
                 .field("snapshot", snapshot.getSnapshotId().getName())
                 .field("version", version.toString())
                 .field("index", index.getName())
-                .field("restoreUUID", restoreUUID);
+                .field("restoreUUID", restoreUUID)
+                .field("isSearchableSnapshot", isSearchableSnapshot)
+                .field("remoteStoreIndexShallowCopy", remoteStoreIndexShallowCopy)
+                .field("sourceRemoteStoreRepository", sourceRemoteStoreRepository);
         }
 
         @Override
@@ -324,18 +395,131 @@ public boolean equals(Object o) {
             return restoreUUID.equals(that.restoreUUID)
                 && snapshot.equals(that.snapshot)
                 && index.equals(that.index)
-                && version.equals(that.version);
+                && version.equals(that.version)
+                && isSearchableSnapshot == that.isSearchableSnapshot
+                && remoteStoreIndexShallowCopy == that.remoteStoreIndexShallowCopy
+                && sourceRemoteStoreRepository != null
+                    ? sourceRemoteStoreRepository.equals(that.sourceRemoteStoreRepository)
+                    : that.sourceRemoteStoreRepository == null;
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(restoreUUID, snapshot, index, version);
+            return Objects.hash(
+                restoreUUID,
+                snapshot,
+                index,
+                version,
+                isSearchableSnapshot,
+                remoteStoreIndexShallowCopy,
+                sourceRemoteStoreRepository
+            );
         }
 
     }
 
+    /**
+     * Recovery from remote store
+     *
+     * @opensearch.internal
+     */
+    public static class RemoteStoreRecoverySource extends RecoverySource {
+
+        private final String restoreUUID;
+        private final IndexId index;
+        private final Version version;
+
+        public RemoteStoreRecoverySource(String restoreUUID, Version version, IndexId indexId) {
+            this.restoreUUID = restoreUUID;
+            this.version = Objects.requireNonNull(version);
+            this.index = Objects.requireNonNull(indexId);
+        }
+
+        RemoteStoreRecoverySource(StreamInput in) throws IOException {
+            restoreUUID = in.readString();
+            version = in.readVersion();
+            if (in.getVersion().onOrAfter(LegacyESVersion.V_7_7_0)) {
+                index = new IndexId(in);
+            } else {
+                index = new IndexId(in.readString(), IndexMetadata.INDEX_UUID_NA_VALUE);
+            }
+        }
+
+        public String restoreUUID() {
+            return restoreUUID;
+        }
+
+        /**
+         * Gets the {@link IndexId} of the recovery source. May contain {@link IndexMetadata#INDEX_UUID_NA_VALUE} as the index uuid if it
+         * was created by an older version cluster-manager in a mixed version cluster.
+         *
+         * @return IndexId
+         */
+        public IndexId index() {
+            return index;
+        }
+
+        public Version version() {
+            return version;
+        }
+
+        @Override
+        protected void writeAdditionalFields(StreamOutput out) throws IOException {
+            out.writeString(restoreUUID);
+            out.writeVersion(version);
+            if (out.getVersion().onOrAfter(LegacyESVersion.V_7_7_0)) {
+                index.writeTo(out);
+            } else {
+                out.writeString(index.getName());
+            }
+        }
+
+        @Override
+        public Type getType() {
+            return Type.REMOTE_STORE;
+        }
+
+        @Override
+        public void addAdditionalFields(XContentBuilder builder, ToXContent.Params params) throws IOException {
+            builder.field("version", version.toString()).field("index", index.getName()).field("restoreUUID", restoreUUID);
+        }
+
+        @Override
+        public String toString() {
+            return "remote store recovery [" + restoreUUID + "]";
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            RemoteStoreRecoverySource that = (RemoteStoreRecoverySource) o;
+            return restoreUUID.equals(that.restoreUUID) && index.equals(that.index) && version.equals(that.version);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(restoreUUID, index, version);
+        }
+
+        // TODO: This override should be removed/be updated to return "true",
+        // i.e. we expect no retention leases, once the following issue is fixed:
+        // https://github.com/opensearch-project/OpenSearch/issues/8795
+        @Override
+        public boolean expectEmptyRetentionLeases() {
+            return false;
+        }
+    }
+
     /**
      * peer recovery from a primary shard
+     *
+     * @opensearch.internal
      */
     public static class PeerRecoverySource extends RecoverySource {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RerouteService.java b/server/src/main/java/org/opensearch/cluster/routing/RerouteService.java
index d540359dc2149..fe6331aebc5a6 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RerouteService.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RerouteService.java
@@ -31,12 +31,14 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.common.Priority;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * Asynchronously performs a cluster reroute, updating any shard states and rebalancing the cluster if appropriate.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface RerouteService {
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RotationShardShuffler.java b/server/src/main/java/org/opensearch/cluster/routing/RotationShardShuffler.java
index 262c6c66de54e..a15d96e9adc99 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RotationShardShuffler.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RotationShardShuffler.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Basic {@link ShardShuffler} implementation that uses an {@link AtomicInteger} to generate seeds and uses a rotation to permute shards.
+ *
+ * @opensearch.internal
  */
 public class RotationShardShuffler extends ShardShuffler {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingChangesObserver.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingChangesObserver.java
index 65f8327881de2..1ec572f7f8cc4 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RoutingChangesObserver.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingChangesObserver.java
@@ -34,6 +34,8 @@
 
 /**
  * Records changes made to {@link RoutingNodes} during an allocation round.
+ *
+ * @opensearch.internal
  */
 public interface RoutingChangesObserver {
     /**
@@ -135,6 +137,11 @@ public void initializedReplicaReinitialized(ShardRouting oldReplica, ShardRoutin
         }
     }
 
+    /**
+     * Observer of routing changes.
+     *
+     * @opensearch.internal
+     */
     class DelegatingRoutingChangesObserver implements RoutingChangesObserver {
 
         private final RoutingChangesObserver[] routingChangesObservers;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingException.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingException.java
index 555d65d0a9638..8db6a21958d4b 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RoutingException.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingException.java
@@ -33,12 +33,14 @@
 package org.opensearch.cluster.routing;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A base {@link Exception}s for all exceptions thrown by routing related operations.
+ *
+ * @opensearch.internal
  */
 public class RoutingException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingNode.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingNode.java
index bf8288885b4a4..e10734eb17e0d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RoutingNode.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingNode.java
@@ -35,8 +35,8 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -55,6 +55,8 @@
 /**
  * A {@link RoutingNode} represents a cluster node associated with a single {@link DiscoveryNode} including all shards
  * that are hosted on that nodes. Each {@link RoutingNode} has a unique node id that can be used to identify the node.
+ *
+ * @opensearch.internal
  */
 public class RoutingNode implements Iterable<ShardRouting> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java
index 2906ba783a5a5..b84a34f30b258 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java
@@ -32,11 +32,8 @@
 
 package org.opensearch.cluster.routing;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.CollectionUtil;
-import org.opensearch.Assertions;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
@@ -46,8 +43,9 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.ArrayDeque;
 import java.util.ArrayList;
@@ -60,10 +58,13 @@
 import java.util.ListIterator;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.Queue;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * {@link RoutingNodes} represents a copy the routing information contained in the {@link ClusterState cluster state}.
@@ -77,8 +78,11 @@
  * <li> {@link #relocateShard} starts relocation of a started shard.
  * <li> {@link #failShard} fails/cancels an assigned shard.
  * </ul>
+ *
+ * @opensearch.internal
  */
 public class RoutingNodes implements Iterable<RoutingNode> {
+    private final Metadata metadata;
 
     private final Map<String, RoutingNode> nodesToShards = new HashMap<>();
 
@@ -94,7 +98,7 @@ public class RoutingNodes implements Iterable<RoutingNode> {
 
     private int relocatingShards = 0;
 
-    private final Map<String, ObjectIntHashMap<String>> nodesPerAttributeNames = new HashMap<>();
+    private final Map<String, Set<String>> nodesPerAttributeNames;
     private final Map<String, Recoveries> recoveriesPerNode = new HashMap<>();
     private final Map<String, Recoveries> initialReplicaRecoveries = new HashMap<>();
     private final Map<String, Recoveries> initialPrimaryRecoveries = new HashMap<>();
@@ -104,19 +108,21 @@ public RoutingNodes(ClusterState clusterState) {
     }
 
     public RoutingNodes(ClusterState clusterState, boolean readOnly) {
+        this.metadata = clusterState.getMetadata();
         this.readOnly = readOnly;
         final RoutingTable routingTable = clusterState.routingTable();
+        this.nodesPerAttributeNames = Collections.synchronizedMap(new HashMap<>());
 
         // fill in the nodeToShards with the "live" nodes
-        for (ObjectCursor<DiscoveryNode> cursor : clusterState.nodes().getDataNodes().values()) {
-            String nodeId = cursor.value.getId();
-            this.nodesToShards.put(cursor.value.getId(), new RoutingNode(nodeId, clusterState.nodes().get(nodeId)));
+        for (final DiscoveryNode cursor : clusterState.nodes().getDataNodes().values()) {
+            String nodeId = cursor.getId();
+            this.nodesToShards.put(cursor.getId(), new RoutingNode(nodeId, clusterState.nodes().get(nodeId)));
         }
 
         // fill in the inverse of node -> shards allocated
         // also fill replicaSet information
-        for (ObjectCursor<IndexRoutingTable> indexRoutingTable : routingTable.indicesRouting().values()) {
-            for (IndexShardRoutingTable indexShard : indexRoutingTable.value) {
+        for (final IndexRoutingTable indexRoutingTable : routingTable.indicesRouting().values()) {
+            for (IndexShardRoutingTable indexShard : indexRoutingTable) {
                 assert indexShard.primary != null;
                 for (ShardRouting shard : indexShard) {
                     // to get all the shards belonging to an index, including the replicas,
@@ -283,18 +289,15 @@ public RoutingNode node(String nodeId) {
         return nodesToShards.get(nodeId);
     }
 
-    public ObjectIntHashMap<String> nodesPerAttributesCounts(String attributeName) {
-        ObjectIntHashMap<String> nodesPerAttributesCounts = nodesPerAttributeNames.get(attributeName);
-        if (nodesPerAttributesCounts != null) {
-            return nodesPerAttributesCounts;
-        }
-        nodesPerAttributesCounts = new ObjectIntHashMap<>();
-        for (RoutingNode routingNode : this) {
-            String attrValue = routingNode.node().getAttributes().get(attributeName);
-            nodesPerAttributesCounts.addTo(attrValue, 1);
-        }
-        nodesPerAttributeNames.put(attributeName, nodesPerAttributesCounts);
-        return nodesPerAttributesCounts;
+    public Stream<RoutingNode> stream() {
+        return nodesToShards.values().stream();
+    }
+
+    public Set<String> nodesPerAttributesCounts(String attributeName) {
+        return nodesPerAttributeNames.computeIfAbsent(
+            attributeName,
+            ignored -> stream().map(r -> r.node().getAttributes().get(attributeName)).filter(Objects::nonNull).collect(Collectors.toSet())
+        );
     }
 
     /**
@@ -367,9 +370,9 @@ public ShardRouting activePrimary(ShardId shardId) {
      * Returns one active replica shard for the given shard id or <code>null</code> if
      * no active replica is found.
      *
-     * Since replicas could possibly be on nodes with a older version of OpenSearch than
-     * the primary is, this will return replicas on the highest version of OpenSearch.
-     *
+     * Since replicas could possibly be on nodes with an older version of OpenSearch than
+     * the primary is, this will return replicas on the highest version of OpenSearch when document
+     * replication is enabled.
      */
     public ShardRouting activeReplicaWithHighestVersion(ShardId shardId) {
         // It's possible for replicaNodeVersion to be null, when disassociating dead nodes
@@ -389,6 +392,30 @@ public ShardRouting activeReplicaWithHighestVersion(ShardId shardId) {
             .orElse(null);
     }
 
+    /**
+     * Returns one active replica shard for the given shard id or <code>null</code> if
+     * no active replica is found.
+     *
+     * Since replicas could possibly be on nodes with a higher version of OpenSearch than
+     * the primary is, this will return replicas on the oldest version of OpenSearch when segment
+     * replication is enabled to allow for replica to read segments from primary.
+     *
+     */
+    public ShardRouting activeReplicaWithOldestVersion(ShardId shardId) {
+        // It's possible for replicaNodeVersion to be null. Therefore, we need to protect against the version being null
+        // (meaning the node will be going away).
+        return assignedShards(shardId).stream()
+            .filter(shr -> !shr.primary() && shr.active())
+            .filter(shr -> node(shr.currentNodeId()) != null)
+            .min(
+                Comparator.comparing(
+                    shr -> node(shr.currentNodeId()).node(),
+                    Comparator.nullsFirst(Comparator.comparing(DiscoveryNode::getVersion))
+                )
+            )
+            .orElse(null);
+    }
+
     /**
      * Returns <code>true</code> iff all replicas are active for the given shard routing. Otherwise <code>false</code>
      */
@@ -700,13 +727,35 @@ assert node(failedShard.currentNodeId()).getByShardId(failedShard.shardId()) ==
             + " was matched but wasn't removed";
     }
 
+    public void swapPrimaryWithReplica(
+        Logger logger,
+        ShardRouting primaryShard,
+        ShardRouting replicaShard,
+        RoutingChangesObserver changes
+    ) {
+        assert primaryShard.primary() : "Invalid primary shard provided";
+        assert !replicaShard.primary() : "Invalid Replica shard provided";
+
+        ShardRouting newPrimary = primaryShard.moveActivePrimaryToReplica();
+        ShardRouting newReplica = replicaShard.moveActiveReplicaToPrimary();
+        updateAssigned(primaryShard, newPrimary);
+        updateAssigned(replicaShard, newReplica);
+        logger.info("Swap relocation performed for shard [{}]", newPrimary.shortSummary());
+        changes.replicaPromoted(newPrimary);
+    }
+
     private void unassignPrimaryAndPromoteActiveReplicaIfExists(
         ShardRouting failedShard,
         UnassignedInfo unassignedInfo,
         RoutingChangesObserver routingChangesObserver
     ) {
         assert failedShard.primary();
-        ShardRouting activeReplica = activeReplicaWithHighestVersion(failedShard.shardId());
+        ShardRouting activeReplica;
+        if (metadata.isSegmentReplicationEnabled(failedShard.getIndexName())) {
+            activeReplica = activeReplicaWithOldestVersion(failedShard.shardId());
+        } else {
+            activeReplica = activeReplicaWithHighestVersion(failedShard.shardId());
+        }
         if (activeReplica == null) {
             moveToUnassigned(failedShard, unassignedInfo);
         } else {
@@ -891,6 +940,11 @@ public int size() {
         return nodesToShards.size();
     }
 
+    /**
+     * Unassigned shard list.
+     *
+     * @opensearch.internal
+     */
     public static final class UnassignedShards implements Iterable<ShardRouting> {
 
         private final RoutingNodes nodes;
@@ -987,6 +1041,11 @@ public void ignoreShard(ShardRouting shard, AllocationStatus allocationStatus, R
             ignored.add(shard);
         }
 
+        /**
+         * An unassigned iterator.
+         *
+         * @opensearch.internal
+         */
         public class UnassignedIterator implements Iterator<ShardRouting>, ExistingShardsAllocator.UnassignedAllocationHandler {
 
             private final ListIterator<ShardRouting> iterator;
@@ -1115,6 +1174,18 @@ public ShardRouting[] drain() {
             primaries = 0;
             return mutableShardRoutings;
         }
+
+        /**
+         * Drains all ignored shards and returns it.
+         * This method will not drain unassigned shards.
+         */
+        public ShardRouting[] drainIgnored() {
+            nodes.ensureMutable();
+            ShardRouting[] mutableShardRoutings = ignored.toArray(new ShardRouting[ignored.size()]);
+            ignored.clear();
+            ignoredPrimaries = 0;
+            return mutableShardRoutings;
+        }
     }
 
     /**
@@ -1270,103 +1341,139 @@ private void ensureMutable() {
     }
 
     /**
-     * Creates an iterator over shards interleaving between nodes: The iterator returns the first shard from
-     * the first node, then the first shard of the second node, etc. until one shard from each node has been returned.
-     * The iterator then resumes on the first node by returning the second shard and continues until all shards from
-     * all the nodes have been returned.
-     * @param movePrimaryFirst if true, all primary shards are iterated over before iterating replica for any node
-     * @return iterator of shard routings
+     * Returns iterator of shard routings used by {@link #nodeInterleavedShardIterator(ShardMovementStrategy)}
+     * @param primaryFirst true when ShardMovementStrategy = ShardMovementStrategy.PRIMARY_FIRST, false when it is ShardMovementStrategy.REPLICA_FIRST
      */
-    public Iterator<ShardRouting> nodeInterleavedShardIterator(boolean movePrimaryFirst) {
+    private Iterator<ShardRouting> buildIteratorForMovementStrategy(boolean primaryFirst) {
         final Queue<Iterator<ShardRouting>> queue = new ArrayDeque<>();
         for (Map.Entry<String, RoutingNode> entry : nodesToShards.entrySet()) {
             queue.add(entry.getValue().copyShards().iterator());
         }
-        if (movePrimaryFirst) {
-            return new Iterator<ShardRouting>() {
-                private Queue<ShardRouting> replicaShards = new ArrayDeque<>();
-                private Queue<Iterator<ShardRouting>> replicaIterators = new ArrayDeque<>();
-
-                public boolean hasNext() {
-                    while (!queue.isEmpty()) {
-                        if (queue.peek().hasNext()) {
-                            return true;
-                        }
-                        queue.poll();
-                    }
-                    if (!replicaShards.isEmpty()) {
+        return new Iterator<ShardRouting>() {
+            private Queue<ShardRouting> shardRoutings = new ArrayDeque<>();
+            private Queue<Iterator<ShardRouting>> shardIterators = new ArrayDeque<>();
+
+            public boolean hasNext() {
+                while (queue.isEmpty() == false) {
+                    if (queue.peek().hasNext()) {
                         return true;
                     }
-                    while (!replicaIterators.isEmpty()) {
-                        if (replicaIterators.peek().hasNext()) {
-                            return true;
-                        }
-                        replicaIterators.poll();
+                    queue.poll();
+                }
+                if (!shardRoutings.isEmpty()) {
+                    return true;
+                }
+                while (!shardIterators.isEmpty()) {
+                    if (shardIterators.peek().hasNext()) {
+                        return true;
                     }
-                    return false;
+                    shardIterators.poll();
                 }
+                return false;
+            }
 
-                public ShardRouting next() {
-                    if (hasNext() == false) {
-                        throw new NoSuchElementException();
-                    }
-                    while (!queue.isEmpty()) {
-                        Iterator<ShardRouting> iter = queue.poll();
+            public ShardRouting next() {
+                if (hasNext() == false) {
+                    throw new NoSuchElementException();
+                }
+                while (!queue.isEmpty()) {
+                    Iterator<ShardRouting> iter = queue.poll();
+                    if (primaryFirst) {
                         if (iter.hasNext()) {
                             ShardRouting result = iter.next();
                             if (result.primary()) {
                                 queue.offer(iter);
                                 return result;
                             }
-                            replicaShards.offer(result);
-                            replicaIterators.offer(iter);
+                            shardRoutings.offer(result);
+                            shardIterators.offer(iter);
+                        }
+                    } else {
+                        while (iter.hasNext()) {
+                            ShardRouting result = iter.next();
+                            if (result.primary() == false) {
+                                queue.offer(iter);
+                                return result;
+                            }
+                            shardRoutings.offer(result);
+                            shardIterators.offer(iter);
                         }
                     }
-                    if (!replicaShards.isEmpty()) {
-                        return replicaShards.poll();
-                    }
-                    Iterator<ShardRouting> replicaIterator = replicaIterators.poll();
-                    ShardRouting replicaShard = replicaIterator.next();
-                    replicaIterators.offer(replicaIterator);
-
-                    assert !replicaShard.primary();
-                    return replicaShard;
                 }
-
-                public void remove() {
-                    throw new UnsupportedOperationException();
+                if (!shardRoutings.isEmpty()) {
+                    return shardRoutings.poll();
                 }
-            };
+                Iterator<ShardRouting> replicaIterator = shardIterators.poll();
+                ShardRouting replicaShard = replicaIterator.next();
+                shardIterators.offer(replicaIterator);
+
+                assert replicaShard.primary() != primaryFirst;
+                return replicaShard;
+            }
+
+            public void remove() {
+                throw new UnsupportedOperationException();
+            }
+
+        };
+    }
+
+    /**
+     * Creates an iterator over shards interleaving between nodes: The iterator returns the first shard from
+     * the first node, then the first shard of the second node, etc. until one shard from each node has been returned.
+     * The iterator then resumes on the first node by returning the second shard and continues until all shards from
+     * all the nodes have been returned.
+     * @param shardMovementStrategy if ShardMovementStrategy.PRIMARY_FIRST, all primary shards are iterated over before iterating replica for any node
+     *                              if ShardMovementStrategy.REPLICA_FIRST, all replica shards are iterated over before iterating primary for any node
+     *                              if ShardMovementStrategy.NO_PREFERENCE, order of replica and primary shards doesn't matter in iteration
+     * @return iterator of shard routings
+     */
+    public Iterator<ShardRouting> nodeInterleavedShardIterator(ShardMovementStrategy shardMovementStrategy) {
+        final Queue<Iterator<ShardRouting>> queue = new ArrayDeque<>();
+        for (Map.Entry<String, RoutingNode> entry : nodesToShards.entrySet()) {
+            queue.add(entry.getValue().copyShards().iterator());
+        }
+        if (shardMovementStrategy == ShardMovementStrategy.PRIMARY_FIRST) {
+            return buildIteratorForMovementStrategy(true);
         } else {
-            return new Iterator<ShardRouting>() {
-                @Override
-                public boolean hasNext() {
-                    while (!queue.isEmpty()) {
-                        if (queue.peek().hasNext()) {
-                            return true;
+            if (shardMovementStrategy == ShardMovementStrategy.REPLICA_FIRST) {
+                return buildIteratorForMovementStrategy(false);
+            } else {
+                return new Iterator<ShardRouting>() {
+                    @Override
+                    public boolean hasNext() {
+                        while (!queue.isEmpty()) {
+                            if (queue.peek().hasNext()) {
+                                return true;
+                            }
+                            queue.poll();
                         }
-                        queue.poll();
+                        return false;
                     }
-                    return false;
-                }
 
-                @Override
-                public ShardRouting next() {
-                    if (hasNext() == false) {
-                        throw new NoSuchElementException();
+                    @Override
+                    public ShardRouting next() {
+                        if (hasNext() == false) {
+                            throw new NoSuchElementException();
+                        }
+                        Iterator<ShardRouting> iter = queue.poll();
+                        queue.offer(iter);
+                        return iter.next();
                     }
-                    Iterator<ShardRouting> iter = queue.poll();
-                    queue.offer(iter);
-                    return iter.next();
-                }
 
-                public void remove() {
-                    throw new UnsupportedOperationException();
-                }
-            };
+                    public void remove() {
+                        throw new UnsupportedOperationException();
+                    }
+                };
+            }
         }
     }
 
+    /**
+     * A collection of recoveries.
+     *
+     * @opensearch.internal
+     */
     private static final class Recoveries {
         private static final Recoveries EMPTY = new Recoveries();
         private int incoming = 0;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingPool.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingPool.java
new file mode 100644
index 0000000000000..a4ff237460e28
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingPool.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexModule;
+
+/**
+ *  {@link RoutingPool} defines the different node types based on the assigned capabilities. The methods
+ *  help decide the capabilities of a specific node as well as an index or shard based on the index configuration.
+ *  These methods help with allocation decisions and determining shard classification with the allocation process.
+ *
+ * @opensearch.internal
+ */
+public enum RoutingPool {
+    LOCAL_ONLY,
+    REMOTE_CAPABLE;
+
+    /**
+     * Helps to determine the appropriate {@link RoutingPool} for a given node from the {@link RoutingNode}
+     */
+    public static RoutingPool getNodePool(RoutingNode node) {
+        return getNodePool(node.node());
+    }
+
+    /**
+     * Helps to determine the appropriate {@link RoutingPool} for a given node from the {@link DiscoveryNode}
+     */
+    public static RoutingPool getNodePool(DiscoveryNode node) {
+        if (node.isSearchNode()) {
+            return REMOTE_CAPABLE;
+        }
+        return LOCAL_ONLY;
+    }
+
+    /**
+     * Can determine the appropriate {@link RoutingPool} for a given shard using the {@link IndexMetadata} for the
+     * index using the {@link RoutingAllocation}.
+     * @param shard the shard routing for which {@link RoutingPool} has to be determined.
+     * @param allocation the current allocation of the cluster
+     * @return {@link RoutingPool} for the given shard.
+     */
+    public static RoutingPool getShardPool(ShardRouting shard, RoutingAllocation allocation) {
+        IndexMetadata indexMetadata = allocation.metadata().getIndexSafe(shard.index());
+        return getIndexPool(indexMetadata);
+    }
+
+    /**
+     * Can determine the appropriate {@link RoutingPool} for a given index using the {@link IndexMetadata}.
+     * @param indexMetadata the index metadata object for which {@link RoutingPool} has to be determined.
+     * @return {@link RoutingPool} for the given index.
+     */
+    public static RoutingPool getIndexPool(IndexMetadata indexMetadata) {
+        Settings indexSettings = indexMetadata.getSettings();
+        if (IndexModule.Type.REMOTE_SNAPSHOT.match(indexSettings.get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey()))) {
+            return REMOTE_CAPABLE;
+        }
+        return LOCAL_ONLY;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingTable.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingTable.java
index d7e3083dffcf6..2b56163f852e8 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/RoutingTable.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingTable.java
@@ -32,23 +32,20 @@
 
 package org.opensearch.cluster.routing;
 
-import com.carrotsearch.hppc.IntSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.Diffable;
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.RecoverySource.RemoteStoreRecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.iterable.Iterables;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 
 import java.io.IOException;
@@ -58,6 +55,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Predicate;
 
 import static org.opensearch.cluster.metadata.MetadataIndexStateService.isIndexVerifiedBeforeClosed;
@@ -67,6 +65,8 @@
  * version of the current routing state.
  *
  * @see IndexRoutingTable
+ *
+ * @opensearch.internal
  */
 public class RoutingTable implements Iterable<IndexRoutingTable>, Diffable<RoutingTable> {
 
@@ -75,11 +75,11 @@ public class RoutingTable implements Iterable<IndexRoutingTable>, Diffable<Routi
     private final long version;
 
     // index to IndexRoutingTable map
-    private final ImmutableOpenMap<String, IndexRoutingTable> indicesRouting;
+    private final Map<String, IndexRoutingTable> indicesRouting;
 
-    private RoutingTable(long version, ImmutableOpenMap<String, IndexRoutingTable> indicesRouting) {
+    private RoutingTable(long version, final Map<String, IndexRoutingTable> indicesRouting) {
         this.version = version;
-        this.indicesRouting = indicesRouting;
+        this.indicesRouting = Collections.unmodifiableMap(indicesRouting);
     }
 
     /**
@@ -109,7 +109,7 @@ public long version() {
 
     @Override
     public Iterator<IndexRoutingTable> iterator() {
-        return indicesRouting.valuesIt();
+        return indicesRouting.values().iterator();
     }
 
     public boolean hasIndex(String index) {
@@ -129,11 +129,11 @@ public IndexRoutingTable index(Index index) {
         return indicesRouting.get(index.getName());
     }
 
-    public ImmutableOpenMap<String, IndexRoutingTable> indicesRouting() {
+    public Map<String, IndexRoutingTable> indicesRouting() {
         return indicesRouting;
     }
 
-    public ImmutableOpenMap<String, IndexRoutingTable> getIndicesRouting() {
+    public Map<String, IndexRoutingTable> getIndicesRouting() {
         return indicesRouting();
     }
 
@@ -211,7 +211,7 @@ public int shardsMatchingPredicateCount(Predicate<ShardRouting> predicate) {
      */
     public List<ShardRouting> allShards() {
         List<ShardRouting> shards = new ArrayList<>();
-        String[] indices = indicesRouting.keys().toArray(String.class);
+        String[] indices = indicesRouting.keySet().toArray(new String[0]);
         for (String index : indices) {
             List<ShardRouting> allShardsIndex = allShards(index);
             shards.addAll(allShardsIndex);
@@ -295,6 +295,16 @@ public ShardsIterator allShardsIncludingRelocationTargets(String[] indices) {
         return allShardsSatisfyingPredicate(indices, shardRouting -> true, true);
     }
 
+    /**
+     * All the shards on the node which match the predicate
+     * @param predicate condition to match
+     * @return iterator over shards matching the predicate
+     */
+    public ShardsIterator allShardsSatisfyingPredicate(Predicate<ShardRouting> predicate) {
+        String[] indices = indicesRouting.keySet().toArray(new String[0]);
+        return allShardsSatisfyingPredicate(indices, predicate, false);
+    }
+
     private ShardsIterator allShardsSatisfyingPredicate(
         String[] indices,
         Predicate<ShardRouting> predicate,
@@ -376,8 +386,8 @@ public static RoutingTable readFrom(StreamInput in) throws IOException {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeLong(version);
         out.writeVInt(indicesRouting.size());
-        for (ObjectCursor<IndexRoutingTable> index : indicesRouting.values()) {
-            index.value.writeTo(out);
+        for (final IndexRoutingTable index : indicesRouting.values()) {
+            index.writeTo(out);
         }
     }
 
@@ -385,7 +395,7 @@ private static class RoutingTableDiff implements Diff<RoutingTable> {
 
         private final long version;
 
-        private final Diff<ImmutableOpenMap<String, IndexRoutingTable>> indicesRouting;
+        private final Diff<Map<String, IndexRoutingTable>> indicesRouting;
 
         RoutingTableDiff(RoutingTable before, RoutingTable after) {
             version = after.version;
@@ -397,7 +407,7 @@ private static class RoutingTableDiff implements Diff<RoutingTable> {
 
         RoutingTableDiff(StreamInput in) throws IOException {
             version = in.readLong();
-            indicesRouting = DiffableUtils.readImmutableOpenMapDiff(in, DiffableUtils.getStringKeySerializer(), DIFF_VALUE_READER);
+            indicesRouting = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(), DIFF_VALUE_READER);
         }
 
         @Override
@@ -422,11 +432,13 @@ public static Builder builder(RoutingTable routingTable) {
 
     /**
      * Builder for the routing table. Note that build can only be called one time.
+     *
+     * @opensearch.internal
      */
     public static class Builder {
 
         private long version;
-        private ImmutableOpenMap.Builder<String, IndexRoutingTable> indicesRouting = ImmutableOpenMap.builder();
+        private Map<String, IndexRoutingTable> indicesRouting = new HashMap<>();
 
         public Builder() {
 
@@ -560,6 +572,18 @@ public Builder addAsFromOpenToClose(IndexMetadata indexMetadata) {
             return add(indexRoutingBuilder);
         }
 
+        public Builder addAsRemoteStoreRestore(
+            IndexMetadata indexMetadata,
+            RemoteStoreRecoverySource recoverySource,
+            Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap,
+            boolean forceRecoveryPrimary
+        ) {
+            IndexRoutingTable.Builder indexRoutingBuilder = new IndexRoutingTable.Builder(indexMetadata.getIndex())
+                .initializeAsRemoteStoreRestore(indexMetadata, recoverySource, indexShardRoutingTableMap, forceRecoveryPrimary);
+            add(indexRoutingBuilder);
+            return this;
+        }
+
         public Builder addAsRestore(IndexMetadata indexMetadata, SnapshotRecoverySource recoverySource) {
             IndexRoutingTable.Builder indexRoutingBuilder = new IndexRoutingTable.Builder(indexMetadata.getIndex()).initializeAsRestore(
                 indexMetadata,
@@ -569,7 +593,11 @@ public Builder addAsRestore(IndexMetadata indexMetadata, SnapshotRecoverySource
             return this;
         }
 
-        public Builder addAsNewRestore(IndexMetadata indexMetadata, SnapshotRecoverySource recoverySource, IntSet ignoreShards) {
+        public Builder addAsNewRestore(
+            IndexMetadata indexMetadata,
+            SnapshotRecoverySource recoverySource,
+            final Set<Integer> ignoreShards
+        ) {
             IndexRoutingTable.Builder indexRoutingBuilder = new IndexRoutingTable.Builder(indexMetadata.getIndex()).initializeAsNewRestore(
                 indexMetadata,
                 recoverySource,
@@ -614,7 +642,7 @@ public RoutingTable build() {
             if (indicesRouting == null) {
                 throw new IllegalStateException("once build is called the builder cannot be reused");
             }
-            RoutingTable table = new RoutingTable(version, indicesRouting.build());
+            RoutingTable table = new RoutingTable(version, indicesRouting);
             indicesRouting = null;
             return table;
         }
@@ -623,8 +651,8 @@ public RoutingTable build() {
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder("routing_table (version ").append(version).append("):\n");
-        for (ObjectObjectCursor<String, IndexRoutingTable> entry : indicesRouting) {
-            sb.append(entry.value.prettyPrint()).append('\n');
+        for (final IndexRoutingTable entry : indicesRouting.values()) {
+            sb.append(entry.prettyPrint()).append('\n');
         }
         return sb.toString();
     }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardIterator.java b/server/src/main/java/org/opensearch/cluster/routing/ShardIterator.java
index 93e05981200c3..623846b6e1dda 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/ShardIterator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardIterator.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 /**
  * Allows to iterate over a set of shard instances (routing) within a shard id group.
+ *
+ * @opensearch.internal
  */
 public interface ShardIterator extends ShardsIterator, Comparable<ShardIterator> {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardMovementStrategy.java b/server/src/main/java/org/opensearch/cluster/routing/ShardMovementStrategy.java
new file mode 100644
index 0000000000000..cfdeed5c227b6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardMovementStrategy.java
@@ -0,0 +1,57 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+
+import java.util.Locale;
+
+/**
+ * ShardMovementStrategy defines the order in which shard movement occurs.
+ *
+ * ShardMovementStrategy values or rather their string representation to be used with
+ * {@link BalancedShardsAllocator#SHARD_MOVEMENT_STRATEGY_SETTING} via cluster settings.
+ *
+ * @opensearch.internal
+ */
+public enum ShardMovementStrategy {
+    /**
+     * default behavior in which order of shard movement doesn't matter.
+     */
+    NO_PREFERENCE,
+
+    /**
+     * primary shards are moved first
+     */
+    PRIMARY_FIRST,
+
+    /**
+     * replica shards are moved first
+     */
+    REPLICA_FIRST;
+
+    public static ShardMovementStrategy parse(String strValue) {
+        if (strValue == null) {
+            return null;
+        } else {
+            strValue = strValue.toUpperCase(Locale.ROOT);
+            try {
+                return ShardMovementStrategy.valueOf(strValue);
+            } catch (IllegalArgumentException e) {
+                throw new IllegalArgumentException("Illegal allocation.shard_movement_strategy value [" + strValue + "]");
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return name().toLowerCase(Locale.ROOT);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardRouting.java b/server/src/main/java/org/opensearch/cluster/routing/ShardRouting.java
index 36c7545c16c5c..666046d97f8d0 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/ShardRouting.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardRouting.java
@@ -36,13 +36,13 @@
 import org.opensearch.cluster.routing.RecoverySource.PeerRecoverySource;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -51,8 +51,10 @@
 /**
  * {@link ShardRouting} immutably encapsulates information about shard
  * indexRoutings like id, state, version, etc.
+ *
+ * @opensearch.internal
  */
-public final class ShardRouting implements Writeable, ToXContentObject {
+public class ShardRouting implements Writeable, ToXContentObject {
 
     /**
      * Used if shard size is not available
@@ -76,7 +78,7 @@ public final class ShardRouting implements Writeable, ToXContentObject {
      * A constructor to internally create shard routing instances, note, the internal flag should only be set to true
      * by either this class or tests. Visible for testing.
      */
-    ShardRouting(
+    protected ShardRouting(
         ShardId shardId,
         String currentNodeId,
         String relocatingNodeId,
@@ -532,6 +534,29 @@ public ShardRouting moveToStarted() {
         );
     }
 
+    /**
+     * Make the active primary shard as replica
+     *
+     * @throws IllegalShardRoutingStateException if shard is already a replica
+     */
+    public ShardRouting moveActivePrimaryToReplica() {
+        assert active() : "expected an active shard " + this;
+        if (!primary) {
+            throw new IllegalShardRoutingStateException(this, "Not a primary shard, can't move to replica");
+        }
+        return new ShardRouting(
+            shardId,
+            currentNodeId,
+            relocatingNodeId,
+            false,
+            state,
+            recoverySource,
+            unassignedInfo,
+            allocationId,
+            expectedShardSize
+        );
+    }
+
     /**
      * Make the active shard primary unless it's not primary
      *
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardRoutingState.java b/server/src/main/java/org/opensearch/cluster/routing/ShardRoutingState.java
index 7152adca6bd95..a46464d8727ee 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/ShardRoutingState.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardRoutingState.java
@@ -35,6 +35,8 @@
 /**
  * Represents the current state of a {@link ShardRouting} as defined by the
  * cluster.
+ *
+ * @opensearch.internal
  */
 public enum ShardRoutingState {
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardShuffler.java b/server/src/main/java/org/opensearch/cluster/routing/ShardShuffler.java
index 663e95b48332c..4fe603213c988 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/ShardShuffler.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardShuffler.java
@@ -36,6 +36,8 @@
 
 /**
  * A shuffler for shards whose primary goal is to balance load.
+ *
+ * @opensearch.internal
  */
 public abstract class ShardShuffler {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/ShardsIterator.java b/server/src/main/java/org/opensearch/cluster/routing/ShardsIterator.java
index 6664de7d9f963..e715be1676c6f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/ShardsIterator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/ShardsIterator.java
@@ -37,6 +37,8 @@
 
 /**
  * Allows to iterate over unrelated shards.
+ *
+ * @opensearch.internal
  */
 public interface ShardsIterator extends Iterable<ShardRouting>, Countable {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/UnassignedInfo.java b/server/src/main/java/org/opensearch/cluster/routing/UnassignedInfo.java
index 09f1708b01307..df3086e295c0f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/UnassignedInfo.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/UnassignedInfo.java
@@ -39,16 +39,16 @@
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -62,6 +62,8 @@
 
 /**
  * Holds additional information as to why the shard is in unassigned state.
+ *
+ * @opensearch.internal
  */
 public final class UnassignedInfo implements ToXContentFragment, Writeable {
 
@@ -79,6 +81,8 @@ public final class UnassignedInfo implements ToXContentFragment, Writeable {
      * <p>
      * Note, ordering of the enum is important, make sure to add new values
      * at the end and handle version serialization properly.
+     *
+     * @opensearch.internal
      */
     public enum Reason {
         /**
@@ -153,6 +157,8 @@ public enum Reason {
      *
      * Note, ordering of the enum is important, make sure to add new values
      * at the end and handle version serialization properly.
+     *
+     * @opensearch.internal
      */
     public enum AllocationStatus implements Writeable {
         /**
@@ -301,7 +307,7 @@ public UnassignedInfo(StreamInput in) throws IOException {
         this.reason = Reason.values()[(int) in.readByte()];
         this.unassignedTimeMillis = in.readLong();
         // As System.nanoTime() cannot be compared across different JVMs, reset it to now.
-        // This means that in master fail-over situations, elapsed delay time is forgotten.
+        // This means that in cluster-manager fail-over situations, elapsed delay time is forgotten.
         this.unassignedTimeNanos = System.nanoTime();
         this.delayed = in.readBoolean();
         this.message = in.readOptionalString();
diff --git a/server/src/main/java/org/opensearch/cluster/routing/UnsupportedWeightedRoutingStateException.java b/server/src/main/java/org/opensearch/cluster/routing/UnsupportedWeightedRoutingStateException.java
new file mode 100644
index 0000000000000..451084fb79100
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/UnsupportedWeightedRoutingStateException.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * Thrown when failing to update the routing weight due to an unsupported state. See {@link WeightedRoutingService} for more details.
+ *
+ * @opensearch.internal
+ */
+public class UnsupportedWeightedRoutingStateException extends OpenSearchException {
+    public UnsupportedWeightedRoutingStateException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public UnsupportedWeightedRoutingStateException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.CONFLICT;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/WeightedRoundRobin.java b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoundRobin.java
new file mode 100644
index 0000000000000..15d437db9c8ff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoundRobin.java
@@ -0,0 +1,106 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Weighted Round Robin Scheduling policy
+ *
+ */
+public class WeightedRoundRobin<T> {
+
+    private List<WeightedRoundRobin.Entity<T>> entities;
+
+    public WeightedRoundRobin(List<WeightedRoundRobin.Entity<T>> entities) {
+        this.entities = entities;
+    }
+
+    /**
+     * *
+     * @return list of entities that is ordered using weighted round-robin scheduling
+     * http://kb.linuxvirtualserver.org/wiki/Weighted_Round-Robin_Scheduling
+     */
+    public List<WeightedRoundRobin.Entity<T>> orderEntities() {
+        int lastSelectedEntity = -1;
+        int size = entities.size();
+        double currentWeight = 0;
+        List<WeightedRoundRobin.Entity<T>> orderedWeight = new ArrayList<>();
+        if (size == 0) {
+            return null;
+        }
+        // Find maximum weight and greatest common divisor of weight across all entities
+        double maxWeight = 0;
+        double sumWeight = 0;
+        Double gcd = null;
+        for (WeightedRoundRobin.Entity<T> entity : entities) {
+            maxWeight = Math.max(maxWeight, entity.getWeight());
+            gcd = (gcd == null) ? entity.getWeight() : gcd(gcd, entity.getWeight());
+            sumWeight += entity.getWeight() > 0 ? entity.getWeight() : 0;
+        }
+        int count = 0;
+        while (count < sumWeight) {
+            lastSelectedEntity = (lastSelectedEntity + 1) % size;
+            if (lastSelectedEntity == 0) {
+                currentWeight = currentWeight - gcd;
+                if (currentWeight <= 0) {
+                    currentWeight = maxWeight;
+                    if (currentWeight == 0) {
+                        return orderedWeight;
+                    }
+                }
+            }
+            if (entities.get(lastSelectedEntity).getWeight() >= currentWeight) {
+                orderedWeight.add(entities.get(lastSelectedEntity));
+                count++;
+            }
+        }
+        return orderedWeight;
+    }
+
+    /**
+     * Return greatest common divisor for two integers
+     * https://en.wikipedia.org/wiki/Greatest_common_divisor#Using_Euclid.27s_algorithm
+     *
+     * @param a first number
+     * @param b second number
+     * @return greatest common divisor
+     */
+    private double gcd(double a, double b) {
+        return (b == 0) ? a : gcd(b, a % b);
+    }
+
+    static final class Entity<T> {
+        private double weight;
+        private T target;
+
+        public Entity(double weight, T target) {
+            this.weight = weight;
+            this.target = target;
+        }
+
+        public T getTarget() {
+            return this.target;
+        }
+
+        public void setTarget(T target) {
+            this.target = target;
+        }
+
+        public double getWeight() {
+            return this.weight;
+        }
+
+        public void setWeight(double weight) {
+            this.weight = weight;
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/WeightedRouting.java b/server/src/main/java/org/opensearch/cluster/routing/WeightedRouting.java
new file mode 100644
index 0000000000000..01471ab664294
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/WeightedRouting.java
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Entity for Weighted Round Robin weights
+ *
+ * @opensearch.internal
+ */
+public class WeightedRouting implements Writeable {
+    private String attributeName;
+    private Map<String, Double> weights;
+
+    public WeightedRouting() {
+        this.attributeName = "";
+        this.weights = new HashMap<>(3);
+    }
+
+    public WeightedRouting(String attributeName, Map<String, Double> weights) {
+        this.attributeName = attributeName;
+        this.weights = weights;
+    }
+
+    public WeightedRouting(WeightedRouting weightedRouting) {
+        this.attributeName = weightedRouting.attributeName();
+        this.weights = weightedRouting.weights;
+    }
+
+    public WeightedRouting(StreamInput in) throws IOException {
+        attributeName = in.readString();
+        weights = (Map<String, Double>) in.readGenericValue();
+    }
+
+    public boolean isSet() {
+        return this.attributeName != null && !this.attributeName.isEmpty() && this.weights != null && !this.weights.isEmpty();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(attributeName);
+        out.writeGenericValue(weights);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        WeightedRouting that = (WeightedRouting) o;
+        if (!attributeName.equals(that.attributeName)) return false;
+        return weights.equals(that.weights);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(attributeName, weights);
+    }
+
+    @Override
+    public String toString() {
+        return "WeightedRouting{" + attributeName + "}{" + weights().toString() + "}";
+    }
+
+    public Map<String, Double> weights() {
+        return this.weights;
+    }
+
+    public String attributeName() {
+        return this.attributeName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingService.java b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingService.java
new file mode 100644
index 0000000000000..c613a630806dd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingService.java
@@ -0,0 +1,303 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.ResourceNotFoundException;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.opensearch.action.ValidateActions.addValidationError;
+import static org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING;
+
+/**
+ * * Service responsible for updating cluster state metadata with weighted routing weights
+ */
+public class WeightedRoutingService {
+    private static final Logger logger = LogManager.getLogger(WeightedRoutingService.class);
+    private final ClusterService clusterService;
+    private final ThreadPool threadPool;
+    private volatile List<String> awarenessAttributes;
+    private volatile Map<String, List<String>> forcedAwarenessAttributes;
+    private static final Double DECOMMISSIONED_AWARENESS_VALUE_WEIGHT = 0.0;
+
+    @Inject
+    public WeightedRoutingService(
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        Settings settings,
+        ClusterSettings clusterSettings
+    ) {
+        this.clusterService = clusterService;
+        this.threadPool = threadPool;
+        this.awarenessAttributes = AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(
+            AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING,
+            this::setAwarenessAttributes
+        );
+        setForcedAwarenessAttributes(CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(
+            CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING,
+            this::setForcedAwarenessAttributes
+        );
+
+    }
+
+    public void registerWeightedRoutingMetadata(
+        final ClusterPutWeightedRoutingRequest request,
+        final ActionListener<ClusterStateUpdateResponse> listener
+    ) {
+        final WeightedRouting newWeightedRouting = new WeightedRouting(request.getWeightedRouting());
+
+        final long requestVersion = request.getVersion();
+        clusterService.submitStateUpdateTask("update_weighted_routing", new ClusterStateUpdateTask(Priority.URGENT) {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                // verify that request object has weights for all discovered and forced awareness values
+                ensureWeightsSetForAllDiscoveredAndForcedAwarenessValues(currentState, request);
+                // verify weights will not be updated for a decommissioned attribute
+                ensureDecommissionedAttributeHasZeroWeight(currentState, request);
+                Metadata metadata = currentState.metadata();
+                Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
+                WeightedRoutingMetadata weightedRoutingMetadata = metadata.custom(WeightedRoutingMetadata.TYPE);
+                ensureNoVersionConflict(requestVersion, weightedRoutingMetadata);
+                if (weightedRoutingMetadata == null) {
+                    logger.info("add weighted routing weights in metadata [{}]", newWeightedRouting);
+                    weightedRoutingMetadata = new WeightedRoutingMetadata(newWeightedRouting, requestVersion + 1);
+                } else {
+                    if (!newWeightedRouting.equals(weightedRoutingMetadata.getWeightedRouting())) {
+                        logger.info("updated weighted routing weights [{}] in metadata", newWeightedRouting);
+                        weightedRoutingMetadata = new WeightedRoutingMetadata(newWeightedRouting, requestVersion + 1);
+                    } else {
+                        logger.info("weights are same, not updating weighted routing weights [{}] in metadata", newWeightedRouting);
+                        return currentState;
+                    }
+                }
+                mdBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+                logger.info("building cluster state with weighted routing weights [{}]", newWeightedRouting);
+                return ClusterState.builder(currentState).metadata(mdBuilder).build();
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.warn(() -> new ParameterizedMessage("failed to update cluster state for weighted routing weights [{}]", e));
+                listener.onFailure(e);
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                logger.debug("cluster weighted routing weights metadata change is processed by all the nodes");
+                listener.onResponse(new ClusterStateUpdateResponse(true));
+            }
+        });
+    }
+
+    public void deleteWeightedRoutingMetadata(
+        final ClusterDeleteWeightedRoutingRequest request,
+        final ActionListener<ClusterDeleteWeightedRoutingResponse> listener
+    ) {
+        final long requestVersion = request.getVersion();
+        final String awarenessAttribute = request.getAwarenessAttribute();
+        clusterService.submitStateUpdateTask("delete_weighted_routing", new ClusterStateUpdateTask(Priority.URGENT) {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                logger.info("Deleting weighted routing metadata from the cluster state");
+                Metadata metadata = currentState.metadata();
+                Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
+                WeightedRoutingMetadata weightedRoutingMetadata = metadata.custom(WeightedRoutingMetadata.TYPE);
+                ensureNoVersionConflict(requestVersion, weightedRoutingMetadata);
+
+                if ((weightedRoutingMetadata != null && awarenessAttribute == null)
+                    || (weightedRoutingMetadata != null
+                        && weightedRoutingMetadata.getWeightedRouting().attributeName().equals(awarenessAttribute))) {
+                    weightedRoutingMetadata = new WeightedRoutingMetadata(new WeightedRouting(), weightedRoutingMetadata.getVersion() + 1);
+                } else {
+                    throw new ResourceNotFoundException(
+                        String.format(
+                            Locale.ROOT,
+                            "weighted routing metadata does not have weights set for awareness attribute %s",
+                            awarenessAttribute
+                        )
+                    );
+                }
+
+                mdBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+                logger.info("building cluster state with weighted routing weights deleted");
+                return ClusterState.builder(currentState).metadata(mdBuilder).build();
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error("failed to remove weighted routing metadata from cluster state", e);
+                listener.onFailure(e);
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                logger.debug("cluster weighted routing metadata change is processed by all the nodes");
+                listener.onResponse(new ClusterDeleteWeightedRoutingResponse(true));
+            }
+        });
+    }
+
+    List<String> getAwarenessAttributes() {
+        return awarenessAttributes;
+    }
+
+    private void setAwarenessAttributes(List<String> awarenessAttributes) {
+        this.awarenessAttributes = awarenessAttributes;
+    }
+
+    private void setForcedAwarenessAttributes(Settings forceSettings) {
+        Map<String, List<String>> forcedAwarenessAttributes = new HashMap<>();
+        Map<String, Settings> forceGroups = forceSettings.getAsGroups();
+        for (Map.Entry<String, Settings> entry : forceGroups.entrySet()) {
+            List<String> aValues = entry.getValue().getAsList("values");
+            if (aValues.size() > 0) {
+                forcedAwarenessAttributes.put(entry.getKey(), aValues);
+            }
+        }
+        this.forcedAwarenessAttributes = forcedAwarenessAttributes;
+    }
+
+    public void verifyAwarenessAttribute(String attributeName) {
+        if (getAwarenessAttributes().contains(attributeName) == false) {
+            ActionRequestValidationException validationException = null;
+            validationException = addValidationError(
+                String.format(Locale.ROOT, "invalid awareness attribute %s requested for weighted routing", attributeName),
+                validationException
+            );
+            throw validationException;
+        }
+    }
+
+    private void ensureWeightsSetForAllDiscoveredAndForcedAwarenessValues(ClusterState state, ClusterPutWeightedRoutingRequest request) {
+        String attributeName = request.getWeightedRouting().attributeName();
+        // build attr_value -> nodes map
+        final Set<String> nodesPerAttribute = state.getRoutingNodes().nodesPerAttributesCounts(attributeName);
+        Set<String> discoveredAwarenessValues = new HashSet<>();
+        for (String stringObjectCursor : nodesPerAttribute) {
+            if (stringObjectCursor != null) discoveredAwarenessValues.add(stringObjectCursor);
+        }
+        Set<String> allAwarenessValues;
+        if (forcedAwarenessAttributes.get(attributeName) == null) {
+            allAwarenessValues = new HashSet<>();
+        } else {
+            allAwarenessValues = new HashSet<>(forcedAwarenessAttributes.get(attributeName));
+        }
+        allAwarenessValues.addAll(discoveredAwarenessValues);
+        AtomicInteger countWithZeroWeight = new AtomicInteger();
+        allAwarenessValues.forEach(awarenessValue -> {
+            if (request.getWeightedRouting().weights().containsKey(awarenessValue) == false) {
+                throw new UnsupportedWeightedRoutingStateException(
+                    "weight for ["
+                        + awarenessValue
+                        + "] is not set and it is part of forced awareness value or a routing node has this attribute."
+                );
+            }
+            if (request.getWeightedRouting().weights().get(awarenessValue) == 0) {
+                countWithZeroWeight.addAndGet(1);
+            }
+        });
+        // We have validations in place to check that not more than half of the values weights are set to 0 in the request object
+        // Adding this check again here on allAwarenessValues such that in no case we land up in a situation where more than half of
+        // discovered awareness values has weight zero
+        if (countWithZeroWeight.get() > allAwarenessValues.size() / 2) {
+            throw addValidationError(
+                (String.format(
+                    Locale.ROOT,
+                    "There are too many discovered attribute values [%s] given zero weight [%d]. Maximum expected number of routing weights having zero weight is [%d]",
+                    request.getWeightedRouting().weights().toString(),
+                    countWithZeroWeight.get(),
+                    allAwarenessValues.size() / 2
+                )),
+                null
+            );
+        }
+    }
+
+    private void ensureDecommissionedAttributeHasZeroWeight(ClusterState state, ClusterPutWeightedRoutingRequest request) {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = state.metadata().decommissionAttributeMetadata();
+        if (decommissionAttributeMetadata == null || decommissionAttributeMetadata.status().equals(DecommissionStatus.FAILED)) {
+            // here either there's no decommission action is ongoing or it is in failed state. In this case, we will allow weight update
+            return;
+        }
+        DecommissionAttribute decommissionAttribute = decommissionAttributeMetadata.decommissionAttribute();
+        WeightedRouting weightedRouting = request.getWeightedRouting();
+        if (weightedRouting.attributeName().equals(decommissionAttribute.attributeName()) == false) {
+            // this is unexpected when a different attribute is requested for decommission and weight update is on another attribute
+            throw new UnsupportedWeightedRoutingStateException(
+                "decommission action ongoing for attribute [{}], cannot update weight for [{}]",
+                decommissionAttribute.attributeName(),
+                weightedRouting.attributeName()
+            );
+        }
+        if (weightedRouting.weights().containsKey(decommissionAttribute.attributeValue()) == false) {
+            // weight of an attribute undergoing decommission must be specified
+            throw new UnsupportedWeightedRoutingStateException(
+                "weight for [{}] is not specified. Please specify its weight to [{}] as it is under decommission action",
+                decommissionAttribute.attributeValue(),
+                DECOMMISSIONED_AWARENESS_VALUE_WEIGHT
+            );
+        }
+        if (Objects.equals(
+            weightedRouting.weights().get(decommissionAttribute.attributeValue()),
+            DECOMMISSIONED_AWARENESS_VALUE_WEIGHT
+        ) == false) {
+            throw new UnsupportedWeightedRoutingStateException(
+                "weight for [{}] must be set to [{}] as it is under decommission action",
+                decommissionAttribute.attributeValue(),
+                DECOMMISSIONED_AWARENESS_VALUE_WEIGHT
+            );
+        }
+    }
+
+    private void ensureNoVersionConflict(long requestedVersion, WeightedRoutingMetadata weightedRoutingMetadata) {
+        if ((weightedRoutingMetadata == null && requestedVersion != WeightedRoutingMetadata.INITIAL_VERSION)
+            || (weightedRoutingMetadata != null && requestedVersion != weightedRoutingMetadata.getVersion())) {
+            throw new UnsupportedWeightedRoutingStateException(
+                String.format(
+                    Locale.ROOT,
+                    "requested version is %s but cluster weighted routing metadata is at a " + "different version %s ",
+                    requestedVersion,
+                    weightedRoutingMetadata != null ? weightedRoutingMetadata.getVersion() : WeightedRoutingMetadata.INITIAL_VERSION
+                )
+            );
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingStats.java b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingStats.java
new file mode 100644
index 0000000000000..49c6ceee74996
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingStats.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Captures weighted shard routing stats per node. See {@link WeightedRoutingService} for more details.
+ *
+ * @opensearch.internal
+ */
+public class WeightedRoutingStats implements ToXContentFragment, Writeable {
+    // number of times fail open has to be executed for search requests
+    private AtomicInteger failOpenCount;
+
+    private static final WeightedRoutingStats INSTANCE = new WeightedRoutingStats();
+
+    public static WeightedRoutingStats getInstance() {
+        return INSTANCE;
+    }
+
+    private WeightedRoutingStats() {
+        failOpenCount = new AtomicInteger(0);
+    }
+
+    public WeightedRoutingStats(StreamInput in) throws IOException {
+        failOpenCount = new AtomicInteger(in.readInt());
+    }
+
+    public void updateFailOpenCount() {
+        failOpenCount.getAndIncrement();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject("weighted_routing");
+        builder.startObject("stats");
+        builder.field("fail_open_count", getFailOpenCount());
+        builder.endObject();
+        builder.endObject();
+        return builder;
+    }
+
+    public int getFailOpenCount() {
+        return failOpenCount.get();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeInt(failOpenCount.get());
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        WeightedRoutingStats that = (WeightedRoutingStats) o;
+        return failOpenCount.equals(that.failOpenCount);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(failOpenCount);
+    }
+
+    public void resetFailOpenCount() {
+        failOpenCount.set(0);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingUtils.java b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingUtils.java
new file mode 100644
index 0000000000000..72387aad0fa45
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/WeightedRoutingUtils.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+
+import java.util.Map;
+import java.util.stream.Stream;
+
+/**
+ *  Utils for Weighted Routing
+ *
+ * @opensearch.internal
+ */
+public class WeightedRoutingUtils {
+
+    /**
+     * This function checks if the node is weighed away ie weighted routing weight is set to 0,
+     *
+     * @param nodeId the node
+     * @return true if the node has attribute value with shard routing weight set to zero, else false
+     */
+    public static boolean isWeighedAway(String nodeId, ClusterState clusterState) {
+        DiscoveryNode node = clusterState.nodes().get(nodeId);
+        if (node == null) {
+            return false;
+        }
+        WeightedRoutingMetadata weightedRoutingMetadata = clusterState.metadata().weightedRoutingMetadata();
+        if (weightedRoutingMetadata != null) {
+            WeightedRouting weightedRouting = weightedRoutingMetadata.getWeightedRouting();
+            if (weightedRouting != null && weightedRouting.isSet()) {
+                // Fetch weighted routing attributes with weight set as zero
+                Stream<String> keys = weightedRouting.weights()
+                    .entrySet()
+                    .stream()
+                    .filter(entry -> entry.getValue().intValue() == WeightedRoutingMetadata.WEIGHED_AWAY_WEIGHT)
+                    .map(Map.Entry::getKey);
+
+                for (Object key : keys.toArray()) {
+                    if (node.getAttributes().get(weightedRouting.attributeName()).equals(key.toString())) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    public static boolean shouldPerformWeightedRouting(boolean ignoreWeightedRouting, WeightedRoutingMetadata weightedRoutingMetadata) {
+        return !ignoreWeightedRouting && weightedRoutingMetadata != null && weightedRoutingMetadata.getWeightedRouting().isSet();
+    }
+
+    public static boolean shouldPerformStrictWeightedRouting(
+        boolean isStrictWeightedShardRouting,
+        boolean ignoreWeightedRouting,
+        WeightedRoutingMetadata weightedRoutingMetadata
+    ) {
+        return isStrictWeightedShardRouting && shouldPerformWeightedRouting(ignoreWeightedRouting, weightedRoutingMetadata);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AbstractAllocationDecision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AbstractAllocationDecision.java
index 1f2f41a99eaba..59a39b358cb70 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/AbstractAllocationDecision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AbstractAllocationDecision.java
@@ -35,11 +35,11 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.decider.Decision.Type;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -50,6 +50,8 @@
 
 /**
  * An abstract class for representing various types of allocation decisions.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractAllocationDecision implements ToXContentFragment, Writeable {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocateUnassignedDecision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocateUnassignedDecision.java
index fb849a1fa6c04..2afdd930cda1f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocateUnassignedDecision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocateUnassignedDecision.java
@@ -37,10 +37,10 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.Decision.Type;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -51,6 +51,8 @@
 
 /**
  * Represents the allocation decision by an allocator for an unassigned shard.
+ *
+ * @opensearch.internal
  */
 public class AllocateUnassignedDecision extends AbstractAllocationDecision {
     /** a constant representing a shard decision where no decision was taken */
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationConstraints.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationConstraints.java
index 793165a0ffd6c..5375910c57579 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationConstraints.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationConstraints.java
@@ -6,79 +6,41 @@
 package org.opensearch.cluster.routing.allocation;
 
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsBalancer;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.function.Predicate;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.isIndexShardsPerNodeBreached;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.isPerIndexPrimaryShardsPerNodeBreached;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.isPrimaryShardsPerNodeBreached;
 
 /**
- * Allocation constraints specify conditions which, if breached, reduce the
- * priority of a node for receiving shard allocations.
+ * Allocation constraints specify conditions which, if breached, reduce the priority of a node for receiving unassigned
+ * shard allocations. Weight calculation in other scenarios like shard movement and re-balancing remain unaffected by
+ * this constraint.
+ *
+ * @opensearch.internal
  */
 public class AllocationConstraints {
-    public final long CONSTRAINT_WEIGHT = 1000000L;
-    private List<Predicate<ConstraintParams>> constraintPredicates;
+    private Map<String, Constraint> constraints;
 
     public AllocationConstraints() {
-        this.constraintPredicates = new ArrayList<>(1);
-        this.constraintPredicates.add(isIndexShardsPerNodeBreached());
+        this.constraints = new HashMap<>();
+        this.constraints.putIfAbsent(INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID, new Constraint(isIndexShardsPerNodeBreached()));
+        this.constraints.putIfAbsent(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, new Constraint(isPerIndexPrimaryShardsPerNodeBreached()));
+        this.constraints.putIfAbsent(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, new Constraint(isPrimaryShardsPerNodeBreached()));
     }
 
-    class ConstraintParams {
-        private BalancedShardsAllocator.Balancer balancer;
-        private BalancedShardsAllocator.ModelNode node;
-        private String index;
-
-        ConstraintParams(BalancedShardsAllocator.Balancer balancer, BalancedShardsAllocator.ModelNode node, String index) {
-            this.balancer = balancer;
-            this.node = node;
-            this.index = index;
-        }
+    public void updateAllocationConstraint(String constraint, boolean enable) {
+        this.constraints.get(constraint).setEnable(enable);
     }
 
-    /**
-     * Evaluates configured allocation constraint predicates for given node - index
-     * combination; and returns a weight value based on the number of breached
-     * constraints.
-     *
-     * Constraint weight should be added to the weight calculated via weight
-     * function, to reduce priority of allocating on nodes with breached
-     * constraints.
-     *
-     * This weight function is used only in case of unassigned shards to avoid overloading a newly added node.
-     * Weight calculation in other scenarios like shard movement and re-balancing remain unaffected by this function.
-     */
-    public long weight(BalancedShardsAllocator.Balancer balancer, BalancedShardsAllocator.ModelNode node, String index) {
-        int constraintsBreached = 0;
-        ConstraintParams params = new ConstraintParams(balancer, node, index);
-        for (Predicate<ConstraintParams> predicate : constraintPredicates) {
-            if (predicate.test(params)) {
-                constraintsBreached++;
-            }
-        }
-        return constraintsBreached * CONSTRAINT_WEIGHT;
+    public long weight(ShardsBalancer balancer, BalancedShardsAllocator.ModelNode node, String index) {
+        Constraint.ConstraintParams params = new Constraint.ConstraintParams(balancer, node, index);
+        return params.weight(constraints);
     }
-
-    /**
-     * Constraint to control number of shards of an index allocated on a single
-     * node.
-     *
-     * In current weight function implementation, when a node has significantly
-     * fewer shards than other nodes (e.g. during single new node addition or node
-     * replacement), its weight is much less than other nodes. All shard allocations
-     * at this time tend to land on the new node with skewed weight. This breaks
-     * index level balance in the cluster, by creating all shards of the same index
-     * on one node, often resulting in a hotspot on that node.
-     *
-     * This constraint is breached when balancer attempts to allocate more than
-     * average shards per index per node.
-     */
-    private Predicate<ConstraintParams> isIndexShardsPerNodeBreached() {
-        return (params) -> {
-            int currIndexShardsOnNode = params.node.numShards(params.index);
-            int allowedIndexShardsPerNode = (int) Math.ceil(params.balancer.avgShardsPerNode(params.index));
-            return (currIndexShardsOnNode >= allowedIndexShardsPerNode);
-        };
-    }
-
 }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationDecision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationDecision.java
index ad6be2a7f4957..3f1c025fce405 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationDecision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationDecision.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.cluster.routing.UnassignedInfo.AllocationStatus;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -44,6 +44,8 @@
 /**
  * An enum which represents the various decision types that can be taken by the
  * allocators and deciders for allocating a shard to a node.
+ *
+ * @opensearch.internal
  */
 public enum AllocationDecision implements Writeable {
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationService.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationService.java
index 53ade0d6c5ae2..8779828aea425 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationService.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AllocationService.java
@@ -54,7 +54,6 @@
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.gateway.PriorityComparator;
 import org.opensearch.snapshots.SnapshotsInfoService;
@@ -62,6 +61,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
@@ -79,6 +79,8 @@
  * {@link AllocationService} keeps {@link AllocationDeciders} to choose nodes
  * for shard allocation. This class also manages new nodes joining the cluster
  * and rerouting of shards.
+ *
+ * @opensearch.internal
  */
 public class AllocationService {
 
@@ -181,9 +183,9 @@ private ClusterState buildResult(ClusterState oldState, RoutingAllocation alloca
         if (restoreInProgress != null) {
             RestoreInProgress updatedRestoreInProgress = allocation.updateRestoreInfoWithRoutingChanges(restoreInProgress);
             if (updatedRestoreInProgress != restoreInProgress) {
-                ImmutableOpenMap.Builder<String, ClusterState.Custom> customsBuilder = ImmutableOpenMap.builder(allocation.getCustoms());
+                final Map<String, ClusterState.Custom> customsBuilder = new HashMap<>(allocation.getCustoms());
                 customsBuilder.put(RestoreInProgress.TYPE, updatedRestoreInProgress);
-                newStateBuilder.customs(customsBuilder.build());
+                newStateBuilder.customs(customsBuilder);
             }
         }
         return newStateBuilder.build();
@@ -740,6 +742,8 @@ public int getNumberOfInFlightFetches() {
     /**
      * this class is used to describe results of applying a set of
      * {@link org.opensearch.cluster.routing.allocation.command.AllocationCommand}
+     *
+     * @opensearch.internal
      */
     public static class CommandsResult {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalance.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalance.java
new file mode 100644
index 0000000000000..19601483d5607
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalance.java
@@ -0,0 +1,125 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.metadata.AutoExpandReplicas;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import static java.lang.Math.max;
+import static org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING;
+import static org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING;
+
+/**
+ * This {@link AwarenessReplicaBalance} gives total unique values of awareness attributes
+ * It takes in effect only iff cluster.routing.allocation.awareness.attributes and
+ * cluster.routing.allocation.awareness.force.zone.values both are specified.
+ *
+ * This is used in enforcing total copy of shard is a maximum of unique values of awareness attributes
+ * Helps in balancing shards across all awareness attributes and ensuring high availability of data.
+ */
+public class AwarenessReplicaBalance {
+    public static final Setting<Boolean> CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING = Setting.boolSetting(
+        "cluster.routing.allocation.awareness.balance",
+        false,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private volatile List<String> awarenessAttributes;
+
+    private volatile Map<String, List<String>> forcedAwarenessAttributes;
+
+    private volatile Boolean awarenessBalance;
+
+    public AwarenessReplicaBalance(Settings settings, ClusterSettings clusterSettings) {
+        this.awarenessAttributes = CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING, this::setAwarenessAttributes);
+        setForcedAwarenessAttributes(CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(
+            CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING,
+            this::setForcedAwarenessAttributes
+        );
+        setAwarenessBalance(CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING, this::setAwarenessBalance);
+
+    }
+
+    private void setAwarenessBalance(Boolean awarenessBalance) {
+        this.awarenessBalance = awarenessBalance;
+    }
+
+    private void setForcedAwarenessAttributes(Settings forceSettings) {
+        Map<String, List<String>> forcedAwarenessAttributes = new HashMap<>();
+        Map<String, Settings> forceGroups = forceSettings.getAsGroups();
+        for (Map.Entry<String, Settings> entry : forceGroups.entrySet()) {
+            List<String> aValues = entry.getValue().getAsList("values");
+            if (aValues.size() > 0) {
+                forcedAwarenessAttributes.put(entry.getKey(), aValues);
+            }
+        }
+        this.forcedAwarenessAttributes = forcedAwarenessAttributes;
+    }
+
+    private void setAwarenessAttributes(List<String> awarenessAttributes) {
+        this.awarenessAttributes = awarenessAttributes;
+    }
+
+    /*
+    For a cluster having zone as awareness attribute , it will return the size of zones if set it forced awareness attributes
+
+    If there are multiple forced awareness attributes, it will return size of the largest list, as all copies of data
+    is supposed to get distributed amongst those.
+
+    cluster.routing.allocation.awareness.attributes: rack_id , zone
+    cluster.routing.allocation.awareness.force.zone.values: zone1, zone2
+    cluster.routing.allocation.awareness.force.rack_id.values: rack_id1, rack_id2, rack_id3
+
+    In this case,  awareness attributes would be 3.
+     */
+    public int maxAwarenessAttributes() {
+        int awarenessAttributes = 1;
+        if (this.awarenessBalance == false) {
+            return awarenessAttributes;
+        }
+        for (String awarenessAttribute : this.awarenessAttributes) {
+            if (forcedAwarenessAttributes.containsKey(awarenessAttribute)) {
+                awarenessAttributes = max(awarenessAttributes, forcedAwarenessAttributes.get(awarenessAttribute).size());
+            }
+        }
+        return awarenessAttributes;
+    }
+
+    public Optional<String> validate(int replicaCount, AutoExpandReplicas autoExpandReplica) {
+        if (autoExpandReplica.isEnabled()) {
+            if ((autoExpandReplica.getMaxReplicas() != Integer.MAX_VALUE)
+                && ((autoExpandReplica.getMaxReplicas() + 1) % maxAwarenessAttributes() != 0)) {
+                String errorMessage = "expected max cap on auto expand to be a multiple of total awareness attributes ["
+                    + maxAwarenessAttributes()
+                    + "]";
+                return Optional.of(errorMessage);
+            }
+        } else {
+            if ((replicaCount + 1) % maxAwarenessAttributes() != 0) {
+                String errorMessage = "expected total copies needs to be a multiple of total awareness attributes ["
+                    + maxAwarenessAttributes()
+                    + "]";
+                return Optional.of(errorMessage);
+            }
+        }
+        return Optional.empty();
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/Constraint.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/Constraint.java
new file mode 100644
index 0000000000000..e9c3c0afcbe88
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/Constraint.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsBalancer;
+
+import java.util.Map;
+import java.util.function.Predicate;
+
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.CONSTRAINT_WEIGHT;
+
+/**
+ * Defines a constraint useful to de-prioritize certain nodes as target of unassigned shards used in {@link AllocationConstraints} or
+ * re-balancing target used in {@link RebalanceConstraints}
+ *
+ * @opensearch.internal
+ */
+public class Constraint implements Predicate<Constraint.ConstraintParams> {
+
+    private boolean enable;
+    private Predicate<ConstraintParams> predicate;
+
+    public Constraint(Predicate<ConstraintParams> constraintPredicate) {
+        this.predicate = constraintPredicate;
+    }
+
+    @Override
+    public boolean test(ConstraintParams constraintParams) {
+        return this.enable && predicate.test(constraintParams);
+    }
+
+    public void setEnable(boolean enable) {
+        this.enable = enable;
+    }
+
+    static class ConstraintParams {
+        private ShardsBalancer balancer;
+        private BalancedShardsAllocator.ModelNode node;
+        private String index;
+
+        ConstraintParams(ShardsBalancer balancer, BalancedShardsAllocator.ModelNode node, String index) {
+            this.balancer = balancer;
+            this.node = node;
+            this.index = index;
+        }
+
+        public ShardsBalancer getBalancer() {
+            return balancer;
+        }
+
+        public BalancedShardsAllocator.ModelNode getNode() {
+            return node;
+        }
+
+        public String getIndex() {
+            return index;
+        }
+
+        /**
+         * Evaluates configured allocation constraint predicates for given node - index
+         * combination; and returns a weight value based on the number of breached
+         * constraints.
+         * <p>
+         * Constraint weight should be added to the weight calculated via weight
+         * function, to reduce priority of allocating on nodes with breached
+         * constraints.
+         * </p>
+         */
+        public long weight(Map<String, Constraint> constraints) {
+            long totalConstraintWeight = 0;
+            for (Constraint constraint : constraints.values()) {
+                if (constraint.test(this)) {
+                    totalConstraintWeight += CONSTRAINT_WEIGHT;
+                }
+            }
+            return totalConstraintWeight;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/ConstraintTypes.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/ConstraintTypes.java
new file mode 100644
index 0000000000000..f209e993518c1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/ConstraintTypes.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import java.util.function.Predicate;
+
+/**
+ * Defines different constraints definitions
+ *
+ * @opensearch.internal
+ */
+public class ConstraintTypes {
+    public final static long CONSTRAINT_WEIGHT = 1000000L;
+
+    /**
+     * Defines per index constraint which is breached when a node contains more than avg number of primary shards for an index
+     */
+    public final static String INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID = "index.primary.shard.balance.constraint";
+
+    /**
+     * Defines a cluster constraint which is breached when a node contains more than avg primary shards across all indices
+     */
+    public final static String CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID = "cluster.primary.shard.balance.constraint";
+
+    /**
+     * Defines an index constraint which is breached when a node contains more than avg number of shards for an index
+     */
+    public final static String INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID = "index.shard.count.constraint";
+
+    /**
+     * Constraint to control number of shards of an index allocated on a single
+     * node.
+     *
+     * In current weight function implementation, when a node has significantly
+     * fewer shards than other nodes (e.g. during single new node addition or node
+     * replacement), its weight is much less than other nodes. All shard allocations
+     * at this time tend to land on the new node with skewed weight. This breaks
+     * index level balance in the cluster, by creating all shards of the same index
+     * on one node, often resulting in a hotspot on that node.
+     *
+     * This constraint is breached when balancer attempts to allocate more than
+     * average shards per index per node.
+     */
+    public static Predicate<Constraint.ConstraintParams> isIndexShardsPerNodeBreached() {
+        return (params) -> {
+            int currIndexShardsOnNode = params.getNode().numShards(params.getIndex());
+            int allowedIndexShardsPerNode = (int) Math.ceil(params.getBalancer().avgShardsPerNode(params.getIndex()));
+            return (currIndexShardsOnNode >= allowedIndexShardsPerNode);
+        };
+    }
+
+    /**
+     * Defines a predicate which returns true when specific to an index, a node contains more than average number of primary
+     * shards. This constraint is used in weight calculation during allocation and rebalancing. When breached a high weight
+     * {@link ConstraintTypes#CONSTRAINT_WEIGHT} is assigned to node resulting in lesser chances of node being selected
+     * as allocation or rebalancing target
+     */
+    public static Predicate<Constraint.ConstraintParams> isPerIndexPrimaryShardsPerNodeBreached() {
+        return (params) -> {
+            int perIndexPrimaryShardCount = params.getNode().numPrimaryShards(params.getIndex());
+            int perIndexAllowedPrimaryShardCount = (int) Math.ceil(params.getBalancer().avgPrimaryShardsPerNode(params.getIndex()));
+            return perIndexPrimaryShardCount > perIndexAllowedPrimaryShardCount;
+        };
+    }
+
+    /**
+     * Defines a predicate which returns true when a node contains more than average number of primary shards. This
+     * constraint is used in weight calculation during allocation only. When breached a high weight {@link ConstraintTypes#CONSTRAINT_WEIGHT}
+     * is assigned to node resulting in lesser chances of node being selected as allocation target
+     */
+    public static Predicate<Constraint.ConstraintParams> isPrimaryShardsPerNodeBreached() {
+        return (params) -> {
+            int primaryShardCount = params.getNode().numPrimaryShards();
+            int allowedPrimaryShardCount = (int) Math.ceil(params.getBalancer().avgPrimaryShardsPerNode());
+            return primaryShardCount >= allowedPrimaryShardCount;
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
index 66cfb26958985..83faa2a4d2f18 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
@@ -32,13 +32,10 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.ObjectLookupContainer;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterInfo;
@@ -46,23 +43,26 @@
 import org.opensearch.cluster.DiskUsage;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.Spliterators;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.LongSupplier;
@@ -74,11 +74,12 @@
  * Listens for a node to go over the high watermark and kicks off an empty
  * reroute if it does. Also responsible for logging about nodes that have
  * passed the disk watermarks
+ *
+ * @opensearch.internal
  */
 public class DiskThresholdMonitor {
 
     private static final Logger logger = LogManager.getLogger(DiskThresholdMonitor.class);
-
     private final DiskThresholdSettings diskThresholdSettings;
     private final Client client;
     private final Supplier<ClusterState> clusterStateSupplier;
@@ -143,7 +144,7 @@ public void onNewInfo(ClusterInfo info) {
             return;
         }
 
-        final ImmutableOpenMap<String, DiskUsage> usages = info.getNodeLeastAvailableDiskUsages();
+        final Map<String, DiskUsage> usages = info.getNodeLeastAvailableDiskUsages();
         if (usages == null) {
             logger.trace("skipping monitor as no disk usage information is available");
             checkFinished();
@@ -157,7 +158,7 @@ public void onNewInfo(ClusterInfo info) {
         final long currentTimeMillis = currentTimeMillisSupplier.getAsLong();
 
         // Clean up nodes that have been removed from the cluster
-        final ObjectLookupContainer<String> nodes = usages.keys();
+        final Set<String> nodes = usages.keySet();
         cleanUpRemovedNodes(nodes, nodesOverLowThreshold);
         cleanUpRemovedNodes(nodes, nodesOverHighThreshold);
         cleanUpRemovedNodes(nodes, nodesOverHighThresholdAndRelocating);
@@ -170,9 +171,9 @@ public void onNewInfo(ClusterInfo info) {
 
         final List<DiskUsage> usagesOverHighThreshold = new ArrayList<>();
 
-        for (final ObjectObjectCursor<String, DiskUsage> entry : usages) {
-            final String node = entry.key;
-            final DiskUsage usage = entry.value;
+        for (final Map.Entry<String, DiskUsage> entry : usages.entrySet()) {
+            final String node = entry.getKey();
+            final DiskUsage usage = entry.getValue();
             final RoutingNode routingNode = routingNodes.node(node);
 
             if (usage.getFreeBytes() < diskThresholdSettings.getFreeBytesThresholdFloodStage().getBytes()
@@ -295,7 +296,7 @@ public void onNewInfo(ClusterInfo info) {
                 }
         }
 
-        final ActionListener<Void> listener = new GroupedActionListener<>(ActionListener.wrap(this::checkFinished), 3);
+        final ActionListener<Void> listener = new GroupedActionListener<>(ActionListener.wrap(this::checkFinished), 4);
 
         if (reroute) {
             logger.debug("rerouting shards: [{}]", explanation);
@@ -362,8 +363,11 @@ public void onNewInfo(ClusterInfo info) {
             logger.trace("no reroute required");
             listener.onResponse(null);
         }
-        final Set<String> indicesToAutoRelease = StreamSupport.stream(state.routingTable().indicesRouting().spliterator(), false)
-            .map(c -> c.key)
+        final Set<String> indicesToAutoRelease = StreamSupport.stream(
+            Spliterators.spliterator(state.routingTable().indicesRouting().entrySet(), 0),
+            false
+        )
+            .map(c -> c.getKey())
             .filter(index -> indicesNotToAutoRelease.contains(index) == false)
             .filter(index -> state.getBlocks().hasIndexBlock(index, IndexMetadata.INDEX_READ_ONLY_ALLOW_DELETE_BLOCK))
             .collect(Collectors.toSet());
@@ -398,6 +402,30 @@ public void onNewInfo(ClusterInfo info) {
         } else {
             listener.onResponse(null);
         }
+
+        // If all the nodes are breaching high disk watermark, we apply index create block to avoid red clusters.
+        if ((state.getBlocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()) == false)
+            && nodes.size() > 0
+            && nodesOverHighThreshold.size() == nodes.size()) {
+            logger.warn(
+                "Putting index create block on cluster as all nodes are breaching high disk watermark. "
+                    + "Number of nodes above high watermark: {}.",
+                nodesOverHighThreshold.size()
+            );
+            setIndexCreateBlock(listener, true);
+        } else if (state.getBlocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id())
+            && diskThresholdSettings.isCreateIndexBlockAutoReleaseEnabled()
+            && nodesOverHighThreshold.size() < nodes.size()) {
+                logger.warn(
+                    "Removing index create block on cluster as all nodes are no longer breaching high disk watermark. "
+                        + "Number of nodes above high watermark: {}. Total numbers of nodes: {}.",
+                    nodesOverHighThreshold.size(),
+                    nodes.size()
+                );
+                setIndexCreateBlock(listener, false);
+            } else {
+                listener.onResponse(null);
+            }
     }
 
     // exposed for tests to override
@@ -414,7 +442,7 @@ long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, Cluste
 
     private void markNodesMissingUsageIneligibleForRelease(
         RoutingNodes routingNodes,
-        ImmutableOpenMap<String, DiskUsage> usages,
+        Map<String, DiskUsage> usages,
         Set<String> indicesToMarkIneligibleForAutoRelease
     ) {
         for (RoutingNode routingNode : routingNodes) {
@@ -433,6 +461,27 @@ private void setLastRunTimeMillis() {
         lastRunTimeMillis.getAndUpdate(l -> Math.max(l, currentTimeMillisSupplier.getAsLong()));
     }
 
+    protected void setIndexCreateBlock(final ActionListener<Void> listener, boolean indexCreateBlock) {
+        final ActionListener<Void> wrappedListener = ActionListener.wrap(r -> {
+            setLastRunTimeMillis();
+            listener.onResponse(r);
+        }, e -> {
+            logger.debug("setting index create block failed", e);
+            setLastRunTimeMillis();
+            listener.onFailure(e);
+        });
+
+        final Settings indexCreateBlockSetting = indexCreateBlock
+            ? Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), Boolean.TRUE.toString()).build()
+            : Settings.builder().putNull(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey()).build();
+
+        client.admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setPersistentSettings(indexCreateBlockSetting)
+            .execute(ActionListener.map(wrappedListener, r -> null));
+    }
+
     protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener<Void> listener, boolean readOnly) {
         // set read-only block but don't block on the response
         ActionListener<Void> wrappedListener = ActionListener.wrap(r -> {
@@ -453,7 +502,7 @@ protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener
             .execute(ActionListener.map(wrappedListener, r -> null));
     }
 
-    private static void cleanUpRemovedNodes(ObjectLookupContainer<String> nodesToKeep, Set<String> nodesToCleanUp) {
+    private static void cleanUpRemovedNodes(Set<String> nodesToKeep, Set<String> nodesToCleanUp) {
         for (String node : nodesToCleanUp) {
             if (nodesToKeep.contains(node) == false) {
                 nodesToCleanUp.remove(node);
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettings.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettings.java
index 38c099cf197fc..02ccb04a2ef54 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettings.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettings.java
@@ -33,13 +33,13 @@
 package org.opensearch.cluster.routing.allocation;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.RatioValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.Arrays;
 import java.util.Iterator;
@@ -49,6 +49,8 @@
 
 /**
  * A container to keep settings for disk thresholds up to date with cluster setting changes.
+ *
+ * @opensearch.internal
  */
 public class DiskThresholdSettings {
     public static final Setting<Boolean> CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING = Setting.boolSetting(
@@ -94,6 +96,12 @@ public class DiskThresholdSettings {
         Setting.Property.Dynamic,
         Setting.Property.NodeScope
     );
+    public static final Setting<Boolean> CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE = Setting.boolSetting(
+        "cluster.blocks.create_index.auto_release",
+        true,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
 
     private volatile String lowWatermarkRaw;
     private volatile String highWatermarkRaw;
@@ -102,6 +110,7 @@ public class DiskThresholdSettings {
     private volatile ByteSizeValue freeBytesThresholdLow;
     private volatile ByteSizeValue freeBytesThresholdHigh;
     private volatile boolean includeRelocations;
+    private volatile boolean createIndexBlockAutoReleaseEnabled;
     private volatile boolean enabled;
     private volatile TimeValue rerouteInterval;
     private volatile Double freeDiskThresholdFloodStage;
@@ -132,14 +141,21 @@ public DiskThresholdSettings(Settings settings, ClusterSettings clusterSettings)
         this.includeRelocations = CLUSTER_ROUTING_ALLOCATION_INCLUDE_RELOCATIONS_SETTING.get(settings);
         this.rerouteInterval = CLUSTER_ROUTING_ALLOCATION_REROUTE_INTERVAL_SETTING.get(settings);
         this.enabled = CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.get(settings);
+        this.createIndexBlockAutoReleaseEnabled = CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE.get(settings);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_LOW_DISK_WATERMARK_SETTING, this::setLowWatermark);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING, this::setHighWatermark);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_DISK_FLOOD_STAGE_WATERMARK_SETTING, this::setFloodStage);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_INCLUDE_RELOCATIONS_SETTING, this::setIncludeRelocations);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_REROUTE_INTERVAL_SETTING, this::setRerouteInterval);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING, this::setEnabled);
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE, this::setCreateIndexBlockAutoReleaseEnabled);
     }
 
+    /**
+     * Validates a low disk watermark.
+     *
+     * @opensearch.internal
+     */
     static final class LowDiskWatermarkValidator implements Setting.Validator<String> {
 
         @Override
@@ -165,6 +181,11 @@ public Iterator<Setting<?>> settings() {
 
     }
 
+    /**
+     * Validates a high disk watermark.
+     *
+     * @opensearch.internal
+     */
     static final class HighDiskWatermarkValidator implements Setting.Validator<String> {
 
         @Override
@@ -190,6 +211,11 @@ public Iterator<Setting<?>> settings() {
 
     }
 
+    /**
+     * Validates the flood stage.
+     *
+     * @opensearch.internal
+     */
     static final class FloodStageValidator implements Setting.Validator<String> {
 
         @Override
@@ -316,6 +342,10 @@ private void setFloodStage(String floodStageRaw) {
         );
     }
 
+    private void setCreateIndexBlockAutoReleaseEnabled(boolean createIndexBlockAutoReleaseEnabled) {
+        this.createIndexBlockAutoReleaseEnabled = createIndexBlockAutoReleaseEnabled;
+    }
+
     /**
      * Gets the raw (uninterpreted) low watermark value as found in the settings.
      */
@@ -370,6 +400,10 @@ public TimeValue getRerouteInterval() {
         return rerouteInterval;
     }
 
+    public boolean isCreateIndexBlockAutoReleaseEnabled() {
+        return createIndexBlockAutoReleaseEnabled;
+    }
+
     String describeLowThreshold() {
         return freeBytesThresholdLow.equals(ByteSizeValue.ZERO)
             ? Strings.format1Decimals(100.0 - freeDiskThresholdLow, "%")
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/ExistingShardsAllocator.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/ExistingShardsAllocator.java
index ca0744f099f84..f1889cdf780d4 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/ExistingShardsAllocator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/ExistingShardsAllocator.java
@@ -45,6 +45,8 @@
 /**
  * Searches for, and allocates, shards for which there is an existing on-disk copy somewhere in the cluster. The default implementation is
  * {@link GatewayAllocator}, but plugins can supply their own implementations too.
+ *
+ * @opensearch.internal
  */
 public interface ExistingShardsAllocator {
 
@@ -84,7 +86,7 @@ void allocateUnassigned(
     AllocateUnassignedDecision explainUnassignedShardAllocation(ShardRouting unassignedShard, RoutingAllocation routingAllocation);
 
     /**
-     * Called when this node becomes the elected master and when it stops being the elected master, so that implementations can clean up any
+     * Called when this node becomes the elected cluster-manager and when it stops being the elected cluster-manager, so that implementations can clean up any
      * in-flight activity from an earlier mastership.
      */
     void cleanCaches();
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/FailedShard.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/FailedShard.java
index 50f363a6dcb96..61ca0f50e93b9 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/FailedShard.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/FailedShard.java
@@ -38,6 +38,8 @@
 
 /**
  * A class representing a failed shard.
+ *
+ * @opensearch.internal
  */
 public class FailedShard {
     private final ShardRouting routingEntry;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/IndexMetadataUpdater.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/IndexMetadataUpdater.java
index 1e6931a0a3b92..ae8d92dae6811 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/IndexMetadataUpdater.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/IndexMetadataUpdater.java
@@ -43,8 +43,8 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Collections;
 import java.util.Comparator;
@@ -63,6 +63,8 @@
  * Primary terms are updated on primary initialization or when an active primary fails.
  *
  * Allocation ids are added for shards that become active and removed for shards that stop being active.
+ *
+ * @opensearch.internal
  */
 public class IndexMetadataUpdater extends RoutingChangesObserver.AbstractRoutingChangesObserver {
     private final Map<ShardId, Updates> shardChanges = new HashMap<>();
@@ -200,7 +202,8 @@ private IndexMetadata.Builder updateInSyncAllocations(
                 if (recoverySource == RecoverySource.ExistingStoreRecoverySource.FORCE_STALE_PRIMARY_INSTANCE) {
                     allocationId = RecoverySource.ExistingStoreRecoverySource.FORCED_ALLOCATION_ID;
                 } else {
-                    assert recoverySource instanceof RecoverySource.SnapshotRecoverySource : recoverySource;
+                    assert (recoverySource instanceof RecoverySource.SnapshotRecoverySource
+                        || recoverySource instanceof RecoverySource.RemoteStoreRecoverySource) : recoverySource;
                     allocationId = updates.initializedPrimary.allocationId().getId();
                 }
                 // forcing a stale primary resets the in-sync allocations to the singleton set with the stale id
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/MoveDecision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/MoveDecision.java
index 4e78c10681a09..fc39f813ca181 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/MoveDecision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/MoveDecision.java
@@ -36,9 +36,9 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.Decision.Type;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -47,6 +47,8 @@
 /**
  * Represents a decision to move a started shard, either because it is no longer allowed to remain on its current node
  * or because moving it to another node will form a better cluster balance.
+ *
+ * @opensearch.internal
  */
 public final class MoveDecision extends AbstractAllocationDecision {
     /** a constant representing no decision taken */
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/NodeAllocationResult.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/NodeAllocationResult.java
index 23a8f93b0844a..ad568fc5ffa57 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/NodeAllocationResult.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/NodeAllocationResult.java
@@ -36,13 +36,13 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Comparator;
@@ -51,6 +51,8 @@
 
 /**
  * This class represents the shard allocation decision and its explanation for a single node.
+ *
+ * @opensearch.internal
  */
 public class NodeAllocationResult implements ToXContentObject, Writeable, Comparable<NodeAllocationResult> {
 
@@ -186,7 +188,11 @@ public int compareTo(NodeAllocationResult other) {
         return nodeResultComparator.compare(this, other);
     }
 
-    /** A class that captures metadata about a shard store on a node. */
+    /**
+     * A class that captures metadata about a shard store on a node.
+     *
+     * @opensearch.internal
+     */
     public static final class ShardStoreInfo implements ToXContentFragment, Writeable {
         private final boolean inSync;
         @Nullable
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/RebalanceConstraints.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/RebalanceConstraints.java
new file mode 100644
index 0000000000000..a4036ec47ec0e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/RebalanceConstraints.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsBalancer;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.isPerIndexPrimaryShardsPerNodeBreached;
+
+/**
+ * Constraints applied during rebalancing round; specify conditions which, if breached, reduce the
+ * priority of a node for receiving shard relocations.
+ *
+ * @opensearch.internal
+ */
+public class RebalanceConstraints {
+
+    private Map<String, Constraint> constraints;
+
+    public RebalanceConstraints() {
+        this.constraints = new HashMap<>();
+        this.constraints.putIfAbsent(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, new Constraint(isPerIndexPrimaryShardsPerNodeBreached()));
+    }
+
+    public void updateRebalanceConstraint(String constraint, boolean enable) {
+        this.constraints.get(constraint).setEnable(enable);
+    }
+
+    public long weight(ShardsBalancer balancer, BalancedShardsAllocator.ModelNode node, String index) {
+        Constraint.ConstraintParams params = new Constraint.ConstraintParams(balancer, node, index);
+        return params.weight(constraints);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/RerouteExplanation.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/RerouteExplanation.java
index 1a9cb4eaae914..6c84957d6a788 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/RerouteExplanation.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/RerouteExplanation.java
@@ -34,16 +34,18 @@
 
 import org.opensearch.cluster.routing.allocation.command.AllocationCommand;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Class encapsulating the explanation for a single {@link AllocationCommand}
  * taken from the Deciders
+ *
+ * @opensearch.internal
  */
 public class RerouteExplanation implements ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingAllocation.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingAllocation.java
index 80fa4d51e66dc..9e8e399384467 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingAllocation.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingAllocation.java
@@ -43,8 +43,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.snapshots.RestoreService.RestoreInProgressUpdater;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
 
@@ -60,6 +59,8 @@
  * The {@link RoutingAllocation} keep the state of the current allocation
  * of shards and holds the {@link AllocationDeciders} which are responsible
  *  for the current routing state.
+ *
+ *  @opensearch.internal
  */
 public class RoutingAllocation {
 
@@ -73,7 +74,7 @@ public class RoutingAllocation {
 
     private final DiscoveryNodes nodes;
 
-    private final ImmutableOpenMap<String, ClusterState.Custom> customs;
+    private final Map<String, ClusterState.Custom> customs;
 
     private final ClusterInfo clusterInfo;
 
@@ -181,7 +182,7 @@ public <T extends ClusterState.Custom> T custom(String key) {
         return (T) customs.get(key);
     }
 
-    public ImmutableOpenMap<String, ClusterState.Custom> getCustoms() {
+    public Map<String, ClusterState.Custom> getCustoms() {
         return customs;
     }
 
@@ -313,6 +314,11 @@ public void setHasPendingAsyncFetch() {
         this.hasPendingAsyncFetch = true;
     }
 
+    /**
+     * Debug mode.
+     *
+     * @opensearch.internal
+     */
     public enum DebugMode {
         /**
          * debug mode is off
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingExplanations.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingExplanations.java
index 55083ce64e6b1..769212703b48b 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingExplanations.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingExplanations.java
@@ -33,10 +33,10 @@
 package org.opensearch.cluster.routing.allocation;
 
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,6 +47,8 @@
 /**
  * Class used to encapsulate a number of {@link RerouteExplanation}
  * explanations.
+ *
+ * @opensearch.internal
  */
 public class RoutingExplanations implements ToXContentFragment {
     private final List<RerouteExplanation> explanations;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingNodesChangedObserver.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingNodesChangedObserver.java
index 7be75d5baf0b2..ca6391aad3500 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingNodesChangedObserver.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/RoutingNodesChangedObserver.java
@@ -39,6 +39,8 @@
 
 /**
  * Records if changes were made to {@link RoutingNodes} during an allocation round.
+ *
+ * @opensearch.internal
  */
 public class RoutingNodesChangedObserver implements RoutingChangesObserver {
     private boolean changed;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/ShardAllocationDecision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/ShardAllocationDecision.java
index 173278e6fccb8..e1a7fb43827f3 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/ShardAllocationDecision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/ShardAllocationDecision.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
@@ -52,6 +52,8 @@
  * the shard is neither unassigned nor started (i.e. it is initializing or relocating),
  * then both {@link #getAllocateDecision()} and {@link #getMoveDecision()} will return
  * objects whose {@code isDecisionTaken()} method returns {@code false}.
+ *
+ * @opensearch.internal
  */
 public final class ShardAllocationDecision implements ToXContentFragment, Writeable {
     public static final ShardAllocationDecision NOT_TAKEN = new ShardAllocationDecision(
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/StaleShard.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/StaleShard.java
index 65fcc9b17a240..b5511f4a177e8 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/StaleShard.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/StaleShard.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 /**
  * A class that represents a stale shard copy.
+ *
+ * @opensearch.internal
  */
 public class StaleShard {
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java
index b3a045af91952..90eff50fd9b5d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java
@@ -34,51 +34,39 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.IntroSorter;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.ShardMovementStrategy;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.UnassignedInfo.AllocationStatus;
 import org.opensearch.cluster.routing.allocation.AllocateUnassignedDecision;
 import org.opensearch.cluster.routing.allocation.AllocationConstraints;
-import org.opensearch.cluster.routing.allocation.AllocationDecision;
+import org.opensearch.cluster.routing.allocation.ConstraintTypes;
 import org.opensearch.cluster.routing.allocation.MoveDecision;
-import org.opensearch.cluster.routing.allocation.NodeAllocationResult;
+import org.opensearch.cluster.routing.allocation.RebalanceConstraints;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.ShardAllocationDecision;
-import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
-import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.cluster.routing.allocation.decider.Decision.Type;
-import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
-import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.gateway.PriorityComparator;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.stream.StreamSupport;
 
-import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID;
 
 /**
  * The {@link BalancedShardsAllocator} re-balances the nodes allocations
- * within an cluster based on a {@link WeightFunction}. The clusters balance is defined by four parameters which can be set
+ * within a cluster based on a {@link WeightFunction}. The clusters balance is defined by four parameters which can be set
  * in the cluster update API that allows changes in real-time:
  * <ul><li><code>cluster.routing.allocation.balance.shard</code> - The <b>shard balance</b> defines the weight factor
  * for shards allocated on a {@link RoutingNode}</li>
@@ -86,10 +74,13 @@
  * of {@link org.opensearch.cluster.routing.ShardRouting}s per index allocated on a specific node</li>
  * <li><code>cluster.routing.allocation.balance.threshold</code> - A <b>threshold</b> to set the minimal optimization
  * value of operations that should be performed</li>
+ * <li><code>cluster.routing.allocation.balance.prefer_primary</code> - Defines whether primary shard balance is desired</li>
  * </ul>
  * <p>
  * These parameters are combined in a {@link WeightFunction} that allows calculation of node weights which
  * are used to re-balance shards based on global as well as per-index factors.
+ *
+ * @opensearch.internal
  */
 public class BalancedShardsAllocator implements ShardsAllocator {
 
@@ -109,12 +100,30 @@ public class BalancedShardsAllocator implements ShardsAllocator {
         Property.Dynamic,
         Property.NodeScope
     );
+
+    /**
+     * Move primary shards first from node for shard movement when shards can not stay on node anymore. {@link LocalShardsBalancer#moveShards()}
+     */
     public static final Setting<Boolean> SHARD_MOVE_PRIMARY_FIRST_SETTING = Setting.boolSetting(
         "cluster.routing.allocation.move.primary_first",
         false,
         Property.Dynamic,
+        Property.NodeScope,
+        Property.Deprecated
+    );
+
+    /**
+     * Decides order in which to move shards from node when shards can not stay on node anymore. {@link LocalShardsBalancer#moveShards()}
+     * Encapsulates behavior of above SHARD_MOVE_PRIMARY_FIRST_SETTING.
+     */
+    public static final Setting<ShardMovementStrategy> SHARD_MOVEMENT_STRATEGY_SETTING = new Setting<ShardMovementStrategy>(
+        "cluster.routing.allocation.shard_movement_strategy",
+        ShardMovementStrategy.NO_PREFERENCE.toString(),
+        ShardMovementStrategy::parse,
+        Property.Dynamic,
         Property.NodeScope
     );
+
     public static final Setting<Float> THRESHOLD_SETTING = Setting.floatSetting(
         "cluster.routing.allocation.balance.threshold",
         1.0f,
@@ -123,7 +132,23 @@ public class BalancedShardsAllocator implements ShardsAllocator {
         Property.NodeScope
     );
 
+    /**
+     * This setting governs whether primary shards balance is desired during allocation. This is used by {@link ConstraintTypes#isPerIndexPrimaryShardsPerNodeBreached()}
+     * and {@link ConstraintTypes#isPrimaryShardsPerNodeBreached} which is used during unassigned shard allocation
+     * {@link LocalShardsBalancer#allocateUnassigned()} and shard re-balance/relocation to a different node via {@link LocalShardsBalancer#balance()} .
+     */
+
+    public static final Setting<Boolean> PREFER_PRIMARY_SHARD_BALANCE = Setting.boolSetting(
+        "cluster.routing.allocation.balance.prefer_primary",
+        false,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     private volatile boolean movePrimaryFirst;
+    private volatile ShardMovementStrategy shardMovementStrategy;
+
+    private volatile boolean preferPrimaryShardBalance;
     private volatile WeightFunction weightFunction;
     private volatile float threshold;
 
@@ -135,19 +160,51 @@ public BalancedShardsAllocator(Settings settings) {
     public BalancedShardsAllocator(Settings settings, ClusterSettings clusterSettings) {
         setWeightFunction(INDEX_BALANCE_FACTOR_SETTING.get(settings), SHARD_BALANCE_FACTOR_SETTING.get(settings));
         setThreshold(THRESHOLD_SETTING.get(settings));
+        setPreferPrimaryShardBalance(PREFER_PRIMARY_SHARD_BALANCE.get(settings));
+        setShardMovementStrategy(SHARD_MOVEMENT_STRATEGY_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(PREFER_PRIMARY_SHARD_BALANCE, this::setPreferPrimaryShardBalance);
         clusterSettings.addSettingsUpdateConsumer(SHARD_MOVE_PRIMARY_FIRST_SETTING, this::setMovePrimaryFirst);
+        clusterSettings.addSettingsUpdateConsumer(SHARD_MOVEMENT_STRATEGY_SETTING, this::setShardMovementStrategy);
         clusterSettings.addSettingsUpdateConsumer(INDEX_BALANCE_FACTOR_SETTING, SHARD_BALANCE_FACTOR_SETTING, this::setWeightFunction);
         clusterSettings.addSettingsUpdateConsumer(THRESHOLD_SETTING, this::setThreshold);
     }
 
+    /**
+     * Changes in deprecated setting SHARD_MOVE_PRIMARY_FIRST_SETTING affect value of its replacement setting SHARD_MOVEMENT_STRATEGY_SETTING.
+     */
     private void setMovePrimaryFirst(boolean movePrimaryFirst) {
         this.movePrimaryFirst = movePrimaryFirst;
+        setShardMovementStrategy(this.shardMovementStrategy);
+    }
+
+    /**
+     * Sets the correct Shard movement strategy to use.
+     * If users are still using deprecated setting `move_primary_first`, we want behavior to remain unchanged.
+     * In the event of changing ShardMovementStrategy setting from default setting NO_PREFERENCE to either PRIMARY_FIRST or REPLICA_FIRST, we want that
+     * to have priority over values set in move_primary_first setting.
+     */
+    private void setShardMovementStrategy(ShardMovementStrategy shardMovementStrategy) {
+        this.shardMovementStrategy = shardMovementStrategy;
+        if (shardMovementStrategy == ShardMovementStrategy.NO_PREFERENCE && this.movePrimaryFirst) {
+            this.shardMovementStrategy = ShardMovementStrategy.PRIMARY_FIRST;
+        }
     }
 
     private void setWeightFunction(float indexBalance, float shardBalanceFactor) {
         weightFunction = new WeightFunction(indexBalance, shardBalanceFactor);
     }
 
+    /**
+     * When primary shards balance is desired, enable primary shard balancing constraints
+     * @param preferPrimaryShardBalance boolean to prefer balancing by primary shard
+     */
+    private void setPreferPrimaryShardBalance(boolean preferPrimaryShardBalance) {
+        this.preferPrimaryShardBalance = preferPrimaryShardBalance;
+        this.weightFunction.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, preferPrimaryShardBalance);
+        this.weightFunction.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, preferPrimaryShardBalance);
+        this.weightFunction.updateRebalanceConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, preferPrimaryShardBalance);
+    }
+
     private void setThreshold(float threshold) {
         this.threshold = threshold;
     }
@@ -158,23 +215,43 @@ public void allocate(RoutingAllocation allocation) {
             failAllocationOfNewPrimaries(allocation);
             return;
         }
-        final Balancer balancer = new Balancer(logger, allocation, movePrimaryFirst, weightFunction, threshold);
-        balancer.allocateUnassigned();
-        balancer.moveShards();
-        balancer.balance();
+        final ShardsBalancer localShardsBalancer = new LocalShardsBalancer(
+            logger,
+            allocation,
+            shardMovementStrategy,
+            weightFunction,
+            threshold,
+            preferPrimaryShardBalance
+        );
+        localShardsBalancer.allocateUnassigned();
+        localShardsBalancer.moveShards();
+        localShardsBalancer.balance();
+
+        final ShardsBalancer remoteShardsBalancer = new RemoteShardsBalancer(logger, allocation);
+        remoteShardsBalancer.allocateUnassigned();
+        remoteShardsBalancer.moveShards();
+        remoteShardsBalancer.balance();
+
     }
 
     @Override
     public ShardAllocationDecision decideShardAllocation(final ShardRouting shard, final RoutingAllocation allocation) {
-        Balancer balancer = new Balancer(logger, allocation, movePrimaryFirst, weightFunction, threshold);
+        ShardsBalancer localShardsBalancer = new LocalShardsBalancer(
+            logger,
+            allocation,
+            shardMovementStrategy,
+            weightFunction,
+            threshold,
+            preferPrimaryShardBalance
+        );
         AllocateUnassignedDecision allocateUnassignedDecision = AllocateUnassignedDecision.NOT_TAKEN;
         MoveDecision moveDecision = MoveDecision.NOT_TAKEN;
         if (shard.unassigned()) {
-            allocateUnassignedDecision = balancer.decideAllocateUnassigned(shard);
+            allocateUnassignedDecision = localShardsBalancer.decideAllocateUnassigned(shard);
         } else {
-            moveDecision = balancer.decideMove(shard);
+            moveDecision = localShardsBalancer.decideMove(shard);
             if (moveDecision.isDecisionTaken() && moveDecision.canRemain()) {
-                MoveDecision rebalanceDecision = balancer.decideRebalance(shard);
+                MoveDecision rebalanceDecision = localShardsBalancer.decideRebalance(shard);
                 moveDecision = rebalanceDecision.withRemainDecision(moveDecision.getCanRemainDecision());
             }
         }
@@ -229,6 +306,13 @@ public float getShardBalance() {
         return weightFunction.shardBalance;
     }
 
+    /**
+     * Returns preferPrimaryShardBalance.
+     */
+    public boolean getPreferPrimaryBalance() {
+        return preferPrimaryShardBalance;
+    }
+
     /**
      * This class is the primary weight function used to create balanced over nodes and shards in the cluster.
      * Currently this function has 3 properties:
@@ -262,6 +346,7 @@ static class WeightFunction {
         private final float theta0;
         private final float theta1;
         private AllocationConstraints constraints;
+        private RebalanceConstraints rebalanceConstraints;
 
         WeightFunction(float indexBalance, float shardBalance) {
             float sum = indexBalance + shardBalance;
@@ -273,923 +358,41 @@ static class WeightFunction {
             this.indexBalance = indexBalance;
             this.shardBalance = shardBalance;
             this.constraints = new AllocationConstraints();
+            this.rebalanceConstraints = new RebalanceConstraints();
+            // Enable index shard per node breach constraint
+            updateAllocationConstraint(INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID, true);
         }
 
-        public float weightWithAllocationConstraints(Balancer balancer, ModelNode node, String index) {
+        public float weightWithAllocationConstraints(ShardsBalancer balancer, ModelNode node, String index) {
             float balancerWeight = weight(balancer, node, index);
             return balancerWeight + constraints.weight(balancer, node, index);
         }
 
-        float weight(Balancer balancer, ModelNode node, String index) {
+        public float weightWithRebalanceConstraints(ShardsBalancer balancer, ModelNode node, String index) {
+            float balancerWeight = weight(balancer, node, index);
+            return balancerWeight + rebalanceConstraints.weight(balancer, node, index);
+        }
+
+        float weight(ShardsBalancer balancer, ModelNode node, String index) {
             final float weightShard = node.numShards() - balancer.avgShardsPerNode();
             final float weightIndex = node.numShards(index) - balancer.avgShardsPerNode(index);
             return theta0 * weightShard + theta1 * weightIndex;
         }
-    }
-
-    /**
-     * A {@link Balancer}
-     */
-    public static class Balancer {
-        private final Logger logger;
-        private final Map<String, ModelNode> nodes;
-        private final RoutingAllocation allocation;
-        private final RoutingNodes routingNodes;
-        private final boolean movePrimaryFirst;
-        private final WeightFunction weight;
-
-        private final float threshold;
-        private final Metadata metadata;
-        private final float avgShardsPerNode;
-        private final NodeSorter sorter;
-        private final Set<RoutingNode> inEligibleTargetNode;
-
-        public Balancer(Logger logger, RoutingAllocation allocation, boolean movePrimaryFirst, WeightFunction weight, float threshold) {
-            this.logger = logger;
-            this.allocation = allocation;
-            this.movePrimaryFirst = movePrimaryFirst;
-            this.weight = weight;
-            this.threshold = threshold;
-            this.routingNodes = allocation.routingNodes();
-            this.metadata = allocation.metadata();
-            avgShardsPerNode = ((float) metadata.getTotalNumberOfShards()) / routingNodes.size();
-            nodes = Collections.unmodifiableMap(buildModelFromAssigned());
-            sorter = newNodeSorter();
-            inEligibleTargetNode = new HashSet<>();
-        }
-
-        /**
-         * Returns an array view on the nodes in the balancer. Nodes should not be removed from this list.
-         */
-        private ModelNode[] nodesArray() {
-            return nodes.values().toArray(new ModelNode[nodes.size()]);
-        }
-
-        /**
-         * Returns the average of shards per node for the given index
-         */
-        public float avgShardsPerNode(String index) {
-            return ((float) metadata.index(index).getTotalNumberOfShards()) / nodes.size();
-        }
-
-        /**
-         * Returns the global average of shards per node
-         */
-        public float avgShardsPerNode() {
-            return avgShardsPerNode;
-        }
-
-        /**
-         * Returns a new {@link NodeSorter} that sorts the nodes based on their
-         * current weight with respect to the index passed to the sorter. The
-         * returned sorter is not sorted. Use {@link NodeSorter#reset(String)}
-         * to sort based on an index.
-         */
-        private NodeSorter newNodeSorter() {
-            return new NodeSorter(nodesArray(), weight, this);
-        }
-
-        /**
-         * The absolute value difference between two weights.
-         */
-        private static float absDelta(float lower, float higher) {
-            assert higher >= lower : higher + " lt " + lower + " but was expected to be gte";
-            return Math.abs(higher - lower);
-        }
-
-        /**
-         * Returns {@code true} iff the weight delta between two nodes is under a defined threshold.
-         * See {@link #THRESHOLD_SETTING} for defining the threshold.
-         */
-        private static boolean lessThan(float delta, float threshold) {
-            /* deltas close to the threshold are "rounded" to the threshold manually
-               to prevent floating point problems if the delta is very close to the
-               threshold ie. 1.000000002 which can trigger unnecessary balance actions*/
-            return delta <= (threshold + 0.001f);
-        }
-
-        /**
-         * Balances the nodes on the cluster model according to the weight function.
-         * The actual balancing is delegated to {@link #balanceByWeights()}
-         */
-        private void balance() {
-            if (logger.isTraceEnabled()) {
-                logger.trace("Start balancing cluster");
-            }
-            if (allocation.hasPendingAsyncFetch()) {
-                /*
-                 * see https://github.com/elastic/elasticsearch/issues/14387
-                 * if we allow rebalance operations while we are still fetching shard store data
-                 * we might end up with unnecessary rebalance operations which can be super confusion/frustrating
-                 * since once the fetches come back we might just move all the shards back again.
-                 * Therefore we only do a rebalance if we have fetched all information.
-                 */
-                logger.debug("skipping rebalance due to in-flight shard/store fetches");
-                return;
-            }
-            if (allocation.deciders().canRebalance(allocation).type() != Type.YES) {
-                logger.trace("skipping rebalance as it is disabled");
-                return;
-            }
-            if (nodes.size() < 2) { /* skip if we only have one node */
-                logger.trace("skipping rebalance as single node only");
-                return;
-            }
-            balanceByWeights();
-        }
-
-        /**
-         * Makes a decision about moving a single shard to a different node to form a more
-         * optimally balanced cluster.  This method is invoked from the cluster allocation
-         * explain API only.
-         */
-        private MoveDecision decideRebalance(final ShardRouting shard) {
-            if (shard.started() == false) {
-                // we can only rebalance started shards
-                return MoveDecision.NOT_TAKEN;
-            }
-
-            Decision canRebalance = allocation.deciders().canRebalance(shard, allocation);
-
-            sorter.reset(shard.getIndexName());
-            ModelNode[] modelNodes = sorter.modelNodes;
-            final String currentNodeId = shard.currentNodeId();
-            // find currently assigned node
-            ModelNode currentNode = null;
-            for (ModelNode node : modelNodes) {
-                if (node.getNodeId().equals(currentNodeId)) {
-                    currentNode = node;
-                    break;
-                }
-            }
-            assert currentNode != null : "currently assigned node could not be found";
-
-            // balance the shard, if a better node can be found
-            final String idxName = shard.getIndexName();
-            final float currentWeight = weight.weight(this, currentNode, idxName);
-            final AllocationDeciders deciders = allocation.deciders();
-            Type rebalanceDecisionType = Type.NO;
-            ModelNode assignedNode = null;
-            List<Tuple<ModelNode, Decision>> betterBalanceNodes = new ArrayList<>();
-            List<Tuple<ModelNode, Decision>> sameBalanceNodes = new ArrayList<>();
-            List<Tuple<ModelNode, Decision>> worseBalanceNodes = new ArrayList<>();
-            for (ModelNode node : modelNodes) {
-                if (node == currentNode) {
-                    continue; // skip over node we're currently allocated to
-                }
-                final Decision canAllocate = deciders.canAllocate(shard, node.getRoutingNode(), allocation);
-                // the current weight of the node in the cluster, as computed by the weight function;
-                // this is a comparison of the number of shards on this node to the number of shards
-                // that should be on each node on average (both taking the cluster as a whole into account
-                // as well as shards per index)
-                final float nodeWeight = weight.weight(this, node, idxName);
-                // if the node we are examining has a worse (higher) weight than the node the shard is
-                // assigned to, then there is no way moving the shard to the node with the worse weight
-                // can make the balance of the cluster better, so we check for that here
-                final boolean betterWeightThanCurrent = nodeWeight <= currentWeight;
-                boolean rebalanceConditionsMet = false;
-                if (betterWeightThanCurrent) {
-                    // get the delta between the weights of the node we are checking and the node that holds the shard
-                    float currentDelta = absDelta(nodeWeight, currentWeight);
-                    // checks if the weight delta is above a certain threshold; if it is not above a certain threshold,
-                    // then even though the node we are examining has a better weight and may make the cluster balance
-                    // more even, it doesn't make sense to execute the heavyweight operation of relocating a shard unless
-                    // the gains make it worth it, as defined by the threshold
-                    boolean deltaAboveThreshold = lessThan(currentDelta, threshold) == false;
-                    // calculate the delta of the weights of the two nodes if we were to add the shard to the
-                    // node in question and move it away from the node that currently holds it.
-                    // hence we add 2.0f to the weight delta
-                    float proposedDelta = 2.0f + nodeWeight - currentWeight;
-                    boolean betterWeightWithShardAdded = proposedDelta < currentDelta;
-
-                    rebalanceConditionsMet = deltaAboveThreshold && betterWeightWithShardAdded;
-                    // if the simulated weight delta with the shard moved away is better than the weight delta
-                    // with the shard remaining on the current node, and we are allowed to allocate to the
-                    // node in question, then allow the rebalance
-                    if (rebalanceConditionsMet && canAllocate.type().higherThan(rebalanceDecisionType)) {
-                        // rebalance to the node, only will get overwritten if the decision here is to
-                        // THROTTLE and we get a decision with YES on another node
-                        rebalanceDecisionType = canAllocate.type();
-                        assignedNode = node;
-                    }
-                }
-                Tuple<ModelNode, Decision> nodeResult = Tuple.tuple(node, canAllocate);
-                if (rebalanceConditionsMet) {
-                    betterBalanceNodes.add(nodeResult);
-                } else if (betterWeightThanCurrent) {
-                    sameBalanceNodes.add(nodeResult);
-                } else {
-                    worseBalanceNodes.add(nodeResult);
-                }
-            }
 
-            int weightRanking = 0;
-            List<NodeAllocationResult> nodeDecisions = new ArrayList<>(modelNodes.length - 1);
-            for (Tuple<ModelNode, Decision> result : betterBalanceNodes) {
-                nodeDecisions.add(
-                    new NodeAllocationResult(
-                        result.v1().routingNode.node(),
-                        AllocationDecision.fromDecisionType(result.v2().type()),
-                        result.v2(),
-                        ++weightRanking
-                    )
-                );
-            }
-            int currentNodeWeightRanking = ++weightRanking;
-            for (Tuple<ModelNode, Decision> result : sameBalanceNodes) {
-                AllocationDecision nodeDecision = result.v2().type() == Type.NO ? AllocationDecision.NO : AllocationDecision.WORSE_BALANCE;
-                nodeDecisions.add(
-                    new NodeAllocationResult(result.v1().routingNode.node(), nodeDecision, result.v2(), currentNodeWeightRanking)
-                );
-            }
-            for (Tuple<ModelNode, Decision> result : worseBalanceNodes) {
-                AllocationDecision nodeDecision = result.v2().type() == Type.NO ? AllocationDecision.NO : AllocationDecision.WORSE_BALANCE;
-                nodeDecisions.add(new NodeAllocationResult(result.v1().routingNode.node(), nodeDecision, result.v2(), ++weightRanking));
-            }
-
-            if (canRebalance.type() != Type.YES || allocation.hasPendingAsyncFetch()) {
-                AllocationDecision allocationDecision = allocation.hasPendingAsyncFetch()
-                    ? AllocationDecision.AWAITING_INFO
-                    : AllocationDecision.fromDecisionType(canRebalance.type());
-                return MoveDecision.cannotRebalance(canRebalance, allocationDecision, currentNodeWeightRanking, nodeDecisions);
-            } else {
-                return MoveDecision.rebalance(
-                    canRebalance,
-                    AllocationDecision.fromDecisionType(rebalanceDecisionType),
-                    assignedNode != null ? assignedNode.routingNode.node() : null,
-                    currentNodeWeightRanking,
-                    nodeDecisions
-                );
-            }
+        void updateAllocationConstraint(String constraint, boolean enable) {
+            this.constraints.updateAllocationConstraint(constraint, enable);
         }
 
-        /**
-         * Balances the nodes on the cluster model according to the weight
-         * function. The configured threshold is the minimum delta between the
-         * weight of the maximum node and the minimum node according to the
-         * {@link WeightFunction}. This weight is calculated per index to
-         * distribute shards evenly per index. The balancer tries to relocate
-         * shards only if the delta exceeds the threshold. In the default case
-         * the threshold is set to {@code 1.0} to enforce gaining relocation
-         * only, or in other words relocations that move the weight delta closer
-         * to {@code 0.0}
-         */
-        private void balanceByWeights() {
-            final AllocationDeciders deciders = allocation.deciders();
-            final ModelNode[] modelNodes = sorter.modelNodes;
-            final float[] weights = sorter.weights;
-            for (String index : buildWeightOrderedIndices()) {
-                IndexMetadata indexMetadata = metadata.index(index);
-
-                // find nodes that have a shard of this index or where shards of this index are allowed to be allocated to,
-                // move these nodes to the front of modelNodes so that we can only balance based on these nodes
-                int relevantNodes = 0;
-                for (int i = 0; i < modelNodes.length; i++) {
-                    ModelNode modelNode = modelNodes[i];
-                    if (modelNode.getIndex(index) != null
-                        || deciders.canAllocate(indexMetadata, modelNode.getRoutingNode(), allocation).type() != Type.NO) {
-                        // swap nodes at position i and relevantNodes
-                        modelNodes[i] = modelNodes[relevantNodes];
-                        modelNodes[relevantNodes] = modelNode;
-                        relevantNodes++;
-                    }
-                }
-
-                if (relevantNodes < 2) {
-                    continue;
-                }
-
-                sorter.reset(index, 0, relevantNodes);
-                int lowIdx = 0;
-                int highIdx = relevantNodes - 1;
-                while (true) {
-                    final ModelNode minNode = modelNodes[lowIdx];
-                    final ModelNode maxNode = modelNodes[highIdx];
-                    advance_range: if (maxNode.numShards(index) > 0) {
-                        final float delta = absDelta(weights[lowIdx], weights[highIdx]);
-                        if (lessThan(delta, threshold)) {
-                            if (lowIdx > 0
-                                && highIdx - 1 > 0 // is there a chance for a higher delta?
-                                && (absDelta(weights[0], weights[highIdx - 1]) > threshold) // check if we need to break at all
-                            ) {
-                                /* This is a special case if allocations from the "heaviest" to the "lighter" nodes is not possible
-                                 * due to some allocation decider restrictions like zone awareness. if one zone has for instance
-                                 * less nodes than another zone. so one zone is horribly overloaded from a balanced perspective but we
-                                 * can't move to the "lighter" shards since otherwise the zone would go over capacity.
-                                 *
-                                 * This break jumps straight to the condition below were we start moving from the high index towards
-                                 * the low index to shrink the window we are considering for balance from the other direction.
-                                 * (check shrinking the window from MAX to MIN)
-                                 * See #3580
-                                 */
-                                break advance_range;
-                            }
-                            if (logger.isTraceEnabled()) {
-                                logger.trace(
-                                    "Stop balancing index [{}]  min_node [{}] weight: [{}]" + "  max_node [{}] weight: [{}]  delta: [{}]",
-                                    index,
-                                    maxNode.getNodeId(),
-                                    weights[highIdx],
-                                    minNode.getNodeId(),
-                                    weights[lowIdx],
-                                    delta
-                                );
-                            }
-                            break;
-                        }
-                        if (logger.isTraceEnabled()) {
-                            logger.trace(
-                                "Balancing from node [{}] weight: [{}] to node [{}] weight: [{}]  delta: [{}]",
-                                maxNode.getNodeId(),
-                                weights[highIdx],
-                                minNode.getNodeId(),
-                                weights[lowIdx],
-                                delta
-                            );
-                        }
-                        if (delta <= 1.0f) {
-                            /*
-                             * prevent relocations that only swap the weights of the two nodes. a relocation must bring us closer to the
-                             * balance if we only achieve the same delta the relocation is useless
-                             *
-                             * NB this comment above was preserved from an earlier version but doesn't obviously describe the code today. We
-                             * already know that lessThan(delta, threshold) == false and threshold defaults to 1.0, so by default we never
-                             * hit this case anyway.
-                             */
-                            logger.trace(
-                                "Couldn't find shard to relocate from node [{}] to node [{}]",
-                                maxNode.getNodeId(),
-                                minNode.getNodeId()
-                            );
-                        } else if (tryRelocateShard(minNode, maxNode, index)) {
-                            /*
-                             * TODO we could be a bit smarter here, we don't need to fully sort necessarily
-                             * we could just find the place to insert linearly but the win might be minor
-                             * compared to the added complexity
-                             */
-                            weights[lowIdx] = sorter.weight(modelNodes[lowIdx]);
-                            weights[highIdx] = sorter.weight(modelNodes[highIdx]);
-                            sorter.sort(0, relevantNodes);
-                            lowIdx = 0;
-                            highIdx = relevantNodes - 1;
-                            continue;
-                        }
-                    }
-                    if (lowIdx < highIdx - 1) {
-                        /* Shrinking the window from MIN to MAX
-                         * we can't move from any shard from the min node lets move on to the next node
-                         * and see if the threshold still holds. We either don't have any shard of this
-                         * index on this node of allocation deciders prevent any relocation.*/
-                        lowIdx++;
-                    } else if (lowIdx > 0) {
-                        /* Shrinking the window from MAX to MIN
-                         * now we go max to min since obviously we can't move anything to the max node
-                         * lets pick the next highest */
-                        lowIdx = 0;
-                        highIdx--;
-                    } else {
-                        /* we are done here, we either can't relocate anymore or we are balanced */
-                        break;
-                    }
-                }
-            }
+        void updateRebalanceConstraint(String constraint, boolean add) {
+            this.rebalanceConstraints.updateRebalanceConstraint(constraint, add);
         }
-
-        /**
-         * This builds a initial index ordering where the indices are returned
-         * in most unbalanced first. We need this in order to prevent over
-         * allocations on added nodes from one index when the weight parameters
-         * for global balance overrule the index balance at an intermediate
-         * state. For example this can happen if we have 3 nodes and 3 indices
-         * with 3 primary and 1 replica shards. At the first stage all three nodes hold
-         * 2 shard for each index. Now we add another node and the first index
-         * is balanced moving three shards from two of the nodes over to the new node since it
-         * has no shards yet and global balance for the node is way below
-         * average. To re-balance we need to move shards back eventually likely
-         * to the nodes we relocated them from.
-         */
-        private String[] buildWeightOrderedIndices() {
-            final String[] indices = allocation.routingTable().indicesRouting().keys().toArray(String.class);
-            final float[] deltas = new float[indices.length];
-            for (int i = 0; i < deltas.length; i++) {
-                sorter.reset(indices[i]);
-                deltas[i] = sorter.delta();
-            }
-            new IntroSorter() {
-
-                float pivotWeight;
-
-                @Override
-                protected void swap(int i, int j) {
-                    final String tmpIdx = indices[i];
-                    indices[i] = indices[j];
-                    indices[j] = tmpIdx;
-                    final float tmpDelta = deltas[i];
-                    deltas[i] = deltas[j];
-                    deltas[j] = tmpDelta;
-                }
-
-                @Override
-                protected int compare(int i, int j) {
-                    return Float.compare(deltas[j], deltas[i]);
-                }
-
-                @Override
-                protected void setPivot(int i) {
-                    pivotWeight = deltas[i];
-                }
-
-                @Override
-                protected int comparePivot(int j) {
-                    return Float.compare(deltas[j], pivotWeight);
-                }
-            }.sort(0, deltas.length);
-
-            return indices;
-        }
-
-        /**
-         * Checks if target node is ineligible and if so, adds to the list
-         * of ineligible target nodes
-         */
-        private void checkAndAddInEligibleTargetNode(RoutingNode targetNode) {
-            Decision nodeLevelAllocationDecision = allocation.deciders().canAllocateAnyShardToNode(targetNode, allocation);
-            if (nodeLevelAllocationDecision.type() != Decision.Type.YES) {
-                inEligibleTargetNode.add(targetNode);
-            }
-        }
-
-        /**
-         * Move started shards that can not be allocated to a node anymore
-         *
-         * For each shard to be moved this function executes a move operation
-         * to the minimal eligible node with respect to the
-         * weight function. If a shard is moved the shard will be set to
-         * {@link ShardRoutingState#RELOCATING} and a shadow instance of this
-         * shard is created with an incremented version in the state
-         * {@link ShardRoutingState#INITIALIZING}.
-         */
-        public void moveShards() {
-            // Iterate over the started shards interleaving between nodes, and check if they can remain. In the presence of throttling
-            // shard movements, the goal of this iteration order is to achieve a fairer movement of shards from the nodes that are
-            // offloading the shards.
-
-            // Trying to eliminate target nodes so that we donot unnecessarily iterate over source nodes
-            // when no target is eligible
-            for (ModelNode currentNode : sorter.modelNodes) {
-                checkAndAddInEligibleTargetNode(currentNode.getRoutingNode());
-            }
-            boolean primariesThrottled = false;
-            for (Iterator<ShardRouting> it = allocation.routingNodes().nodeInterleavedShardIterator(movePrimaryFirst); it.hasNext();) {
-                // Verify if the cluster concurrent recoveries have been reached.
-                if (allocation.deciders().canMoveAnyShard(allocation).type() != Decision.Type.YES) {
-                    logger.info(
-                        "Cannot move any shard in the cluster due to cluster concurrent recoveries getting breached"
-                            + ". Skipping shard iteration"
-                    );
-                    return;
-                }
-                // Early terminate node interleaved shard iteration when no eligible target nodes are available
-                if (sorter.modelNodes.length == inEligibleTargetNode.size()) {
-                    logger.info(
-                        "Cannot move any shard in the cluster as there is no node on which shards can be allocated"
-                            + ". Skipping shard iteration"
-                    );
-                    return;
-                }
-
-                ShardRouting shardRouting = it.next();
-
-                // Ensure that replicas don't relocate if primaries are being throttled and primary first is enabled
-                if (movePrimaryFirst && primariesThrottled && !shardRouting.primary()) {
-                    logger.info(
-                        "Cannot move any replica shard in the cluster as movePrimaryFirst is enabled and primary shards"
-                            + "are being throttled. Skipping shard iteration"
-                    );
-                    return;
-                }
-
-                // Verify if the shard is allowed to move if outgoing recovery on the node hosting the primary shard
-                // is not being throttled.
-                Decision canMoveAwayDecision = allocation.deciders().canMoveAway(shardRouting, allocation);
-                if (canMoveAwayDecision.type() != Decision.Type.YES) {
-                    if (logger.isDebugEnabled()) logger.debug("Cannot move away shard [{}] Skipping this shard", shardRouting);
-                    if (shardRouting.primary() && canMoveAwayDecision.type() == Type.THROTTLE) {
-                        primariesThrottled = true;
-                    }
-                    continue;
-                }
-
-                final MoveDecision moveDecision = decideMove(shardRouting);
-                if (moveDecision.isDecisionTaken() && moveDecision.forceMove()) {
-                    final ModelNode sourceNode = nodes.get(shardRouting.currentNodeId());
-                    final ModelNode targetNode = nodes.get(moveDecision.getTargetNode().getId());
-                    sourceNode.removeShard(shardRouting);
-                    Tuple<ShardRouting, ShardRouting> relocatingShards = routingNodes.relocateShard(
-                        shardRouting,
-                        targetNode.getNodeId(),
-                        allocation.clusterInfo().getShardSize(shardRouting, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE),
-                        allocation.changes()
-                    );
-                    targetNode.addShard(relocatingShards.v2());
-                    if (logger.isTraceEnabled()) {
-                        logger.trace("Moved shard [{}] to node [{}]", shardRouting, targetNode.getRoutingNode());
-                    }
-
-                    // Verifying if this node can be considered ineligible for further iterations
-                    if (targetNode != null) {
-                        checkAndAddInEligibleTargetNode(targetNode.getRoutingNode());
-                    }
-                } else if (moveDecision.isDecisionTaken() && moveDecision.canRemain() == false) {
-                    logger.trace("[{}][{}] can't move", shardRouting.index(), shardRouting.id());
-                }
-            }
-        }
-
-        /**
-         * Makes a decision on whether to move a started shard to another node.  The following rules apply
-         * to the {@link MoveDecision} return object:
-         *   1. If the shard is not started, no decision will be taken and {@link MoveDecision#isDecisionTaken()} will return false.
-         *   2. If the shard is allowed to remain on its current node, no attempt will be made to move the shard and
-         *      {@link MoveDecision#getCanRemainDecision} will have a decision type of YES.  All other fields in the object will be null.
-         *   3. If the shard is not allowed to remain on its current node, then {@link MoveDecision#getAllocationDecision()} will be
-         *      populated with the decision of moving to another node.  If {@link MoveDecision#forceMove()} ()} returns {@code true}, then
-         *      {@link MoveDecision#getTargetNode} will return a non-null value, otherwise the assignedNodeId will be null.
-         *   4. If the method is invoked in explain mode (e.g. from the cluster allocation explain APIs), then
-         *      {@link MoveDecision#getNodeDecisions} will have a non-null value.
-         */
-        public MoveDecision decideMove(final ShardRouting shardRouting) {
-            if (shardRouting.started() == false) {
-                // we can only move started shards
-                return MoveDecision.NOT_TAKEN;
-            }
-
-            final boolean explain = allocation.debugDecision();
-            final ModelNode sourceNode = nodes.get(shardRouting.currentNodeId());
-            assert sourceNode != null && sourceNode.containsShard(shardRouting);
-            RoutingNode routingNode = sourceNode.getRoutingNode();
-            Decision canRemain = allocation.deciders().canRemain(shardRouting, routingNode, allocation);
-            if (canRemain.type() != Decision.Type.NO) {
-                return MoveDecision.stay(canRemain);
-            }
-
-            sorter.reset(shardRouting.getIndexName());
-            /*
-             * the sorter holds the minimum weight node first for the shards index.
-             * We now walk through the nodes until we find a node to allocate the shard.
-             * This is not guaranteed to be balanced after this operation we still try best effort to
-             * allocate on the minimal eligible node.
-             */
-            Type bestDecision = Type.NO;
-            RoutingNode targetNode = null;
-            final List<NodeAllocationResult> nodeExplanationMap = explain ? new ArrayList<>() : null;
-            int weightRanking = 0;
-            int targetNodeProcessed = 0;
-            for (ModelNode currentNode : sorter.modelNodes) {
-                if (currentNode != sourceNode) {
-                    RoutingNode target = currentNode.getRoutingNode();
-                    if (!explain && inEligibleTargetNode.contains(target)) continue;
-                    // don't use canRebalance as we want hard filtering rules to apply. See #17698
-                    if (!explain) {
-                        // If we cannot allocate any shard to node marking it in eligible
-                        Decision nodeLevelAllocationDecision = allocation.deciders().canAllocateAnyShardToNode(target, allocation);
-                        if (nodeLevelAllocationDecision.type() != Decision.Type.YES) {
-                            inEligibleTargetNode.add(currentNode.getRoutingNode());
-                            continue;
-                        }
-                    }
-                    targetNodeProcessed++;
-                    // don't use canRebalance as we want hard filtering rules to apply. See #17698
-                    Decision allocationDecision = allocation.deciders().canAllocate(shardRouting, target, allocation);
-                    if (explain) {
-                        nodeExplanationMap.add(
-                            new NodeAllocationResult(currentNode.getRoutingNode().node(), allocationDecision, ++weightRanking)
-                        );
-                    }
-                    // TODO maybe we can respect throttling here too?
-                    if (allocationDecision.type().higherThan(bestDecision)) {
-                        bestDecision = allocationDecision.type();
-                        if (bestDecision == Type.YES) {
-                            targetNode = target;
-                            if (explain == false) {
-                                // we are not in explain mode and already have a YES decision on the best weighted node,
-                                // no need to continue iterating
-                                break;
-                            }
-                        }
-                    }
-                }
-            }
-
-            return MoveDecision.cannotRemain(
-                canRemain,
-                AllocationDecision.fromDecisionType(bestDecision),
-                targetNode != null ? targetNode.node() : null,
-                nodeExplanationMap
-            );
-        }
-
-        /**
-         * Builds the internal model from all shards in the given
-         * {@link Iterable}. All shards in the {@link Iterable} must be assigned
-         * to a node. This method will skip shards in the state
-         * {@link ShardRoutingState#RELOCATING} since each relocating shard has
-         * a shadow shard in the state {@link ShardRoutingState#INITIALIZING}
-         * on the target node which we respect during the allocation / balancing
-         * process. In short, this method recreates the status-quo in the cluster.
-         */
-        private Map<String, ModelNode> buildModelFromAssigned() {
-            Map<String, ModelNode> nodes = new HashMap<>();
-            for (RoutingNode rn : routingNodes) {
-                ModelNode node = new ModelNode(rn);
-                nodes.put(rn.nodeId(), node);
-                for (ShardRouting shard : rn) {
-                    assert rn.nodeId().equals(shard.currentNodeId());
-                    /* we skip relocating shards here since we expect an initializing shard with the same id coming in */
-                    if (shard.state() != RELOCATING) {
-                        node.addShard(shard);
-                        if (logger.isTraceEnabled()) {
-                            logger.trace("Assigned shard [{}] to node [{}]", shard, node.getNodeId());
-                        }
-                    }
-                }
-            }
-            return nodes;
-        }
-
-        /**
-         * Allocates all given shards on the minimal eligible node for the shards index
-         * with respect to the weight function. All given shards must be unassigned.
-         */
-        private void allocateUnassigned() {
-            RoutingNodes.UnassignedShards unassigned = routingNodes.unassigned();
-            assert !nodes.isEmpty();
-            if (logger.isTraceEnabled()) {
-                logger.trace("Start allocating unassigned shards");
-            }
-            if (unassigned.isEmpty()) {
-                return;
-            }
-
-            /*
-             * TODO: We could be smarter here and group the shards by index and then
-             * use the sorter to save some iterations.
-             */
-            final PriorityComparator secondaryComparator = PriorityComparator.getAllocationComparator(allocation);
-            final Comparator<ShardRouting> comparator = (o1, o2) -> {
-                if (o1.primary() ^ o2.primary()) {
-                    return o1.primary() ? -1 : 1;
-                }
-                final int indexCmp;
-                if ((indexCmp = o1.getIndexName().compareTo(o2.getIndexName())) == 0) {
-                    return o1.getId() - o2.getId();
-                }
-                // this comparator is more expensive than all the others up there
-                // that's why it's added last even though it could be easier to read
-                // if we'd apply it earlier. this comparator will only differentiate across
-                // indices all shards of the same index is treated equally.
-                final int secondary = secondaryComparator.compare(o1, o2);
-                return secondary == 0 ? indexCmp : secondary;
-            };
-            /*
-             * we use 2 arrays and move replicas to the second array once we allocated an identical
-             * replica in the current iteration to make sure all indices get allocated in the same manner.
-             * The arrays are sorted by primaries first and then by index and shard ID so a 2 indices with
-             * 2 replica and 1 shard would look like:
-             * [(0,P,IDX1), (0,P,IDX2), (0,R,IDX1), (0,R,IDX1), (0,R,IDX2), (0,R,IDX2)]
-             * if we allocate for instance (0, R, IDX1) we move the second replica to the secondary array and proceed with
-             * the next replica. If we could not find a node to allocate (0,R,IDX1) we move all it's replicas to ignoreUnassigned.
-             */
-            ShardRouting[] primary = unassigned.drain();
-            ShardRouting[] secondary = new ShardRouting[primary.length];
-            int secondaryLength = 0;
-            int primaryLength = primary.length;
-            ArrayUtil.timSort(primary, comparator);
-            do {
-                for (int i = 0; i < primaryLength; i++) {
-                    ShardRouting shard = primary[i];
-                    final AllocateUnassignedDecision allocationDecision = decideAllocateUnassigned(shard);
-                    final String assignedNodeId = allocationDecision.getTargetNode() != null
-                        ? allocationDecision.getTargetNode().getId()
-                        : null;
-                    final ModelNode minNode = assignedNodeId != null ? nodes.get(assignedNodeId) : null;
-
-                    if (allocationDecision.getAllocationDecision() == AllocationDecision.YES) {
-                        if (logger.isTraceEnabled()) {
-                            logger.trace("Assigned shard [{}] to [{}]", shard, minNode.getNodeId());
-                        }
-
-                        final long shardSize = DiskThresholdDecider.getExpectedShardSize(
-                            shard,
-                            ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE,
-                            allocation.clusterInfo(),
-                            allocation.snapshotShardSizeInfo(),
-                            allocation.metadata(),
-                            allocation.routingTable()
-                        );
-                        shard = routingNodes.initializeShard(shard, minNode.getNodeId(), null, shardSize, allocation.changes());
-                        minNode.addShard(shard);
-                        if (!shard.primary()) {
-                            // copy over the same replica shards to the secondary array so they will get allocated
-                            // in a subsequent iteration, allowing replicas of other shards to be allocated first
-                            while (i < primaryLength - 1 && comparator.compare(primary[i], primary[i + 1]) == 0) {
-                                secondary[secondaryLength++] = primary[++i];
-                            }
-                        }
-                    } else {
-                        // did *not* receive a YES decision
-                        if (logger.isTraceEnabled()) {
-                            logger.trace(
-                                "No eligible node found to assign shard [{}] allocation_status [{}]",
-                                shard,
-                                allocationDecision.getAllocationStatus()
-                            );
-                        }
-
-                        if (minNode != null) {
-                            // throttle decision scenario
-                            assert allocationDecision.getAllocationStatus() == AllocationStatus.DECIDERS_THROTTLED;
-                            final long shardSize = DiskThresholdDecider.getExpectedShardSize(
-                                shard,
-                                ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE,
-                                allocation.clusterInfo(),
-                                allocation.snapshotShardSizeInfo(),
-                                allocation.metadata(),
-                                allocation.routingTable()
-                            );
-                            minNode.addShard(shard.initialize(minNode.getNodeId(), null, shardSize));
-                        } else {
-                            if (logger.isTraceEnabled()) {
-                                logger.trace("No Node found to assign shard [{}]", shard);
-                            }
-                        }
-
-                        unassigned.ignoreShard(shard, allocationDecision.getAllocationStatus(), allocation.changes());
-                        if (!shard.primary()) { // we could not allocate it and we are a replica - check if we can ignore the other replicas
-                            while (i < primaryLength - 1 && comparator.compare(primary[i], primary[i + 1]) == 0) {
-                                unassigned.ignoreShard(primary[++i], allocationDecision.getAllocationStatus(), allocation.changes());
-                            }
-                        }
-                    }
-                }
-                primaryLength = secondaryLength;
-                ShardRouting[] tmp = primary;
-                primary = secondary;
-                secondary = tmp;
-                secondaryLength = 0;
-            } while (primaryLength > 0);
-            // clear everything we have either added it or moved to ignoreUnassigned
-        }
-
-        /**
-         * Make a decision for allocating an unassigned shard.  This method returns a two values in a tuple: the
-         * first value is the {@link Decision} taken to allocate the unassigned shard, the second value is the
-         * {@link ModelNode} representing the node that the shard should be assigned to.  If the decision returned
-         * is of type {@link Type#NO}, then the assigned node will be null.
-         */
-        private AllocateUnassignedDecision decideAllocateUnassigned(final ShardRouting shard) {
-            if (shard.assignedToNode()) {
-                // we only make decisions for unassigned shards here
-                return AllocateUnassignedDecision.NOT_TAKEN;
-            }
-
-            final boolean explain = allocation.debugDecision();
-            Decision shardLevelDecision = allocation.deciders().canAllocate(shard, allocation);
-            if (shardLevelDecision.type() == Type.NO && explain == false) {
-                // NO decision for allocating the shard, irrespective of any particular node, so exit early
-                return AllocateUnassignedDecision.no(AllocationStatus.DECIDERS_NO, null);
-            }
-
-            /* find an node with minimal weight we can allocate on*/
-            float minWeight = Float.POSITIVE_INFINITY;
-            ModelNode minNode = null;
-            Decision decision = null;
-            /* Don't iterate over an identity hashset here the
-             * iteration order is different for each run and makes testing hard */
-            Map<String, NodeAllocationResult> nodeExplanationMap = explain ? new HashMap<>() : null;
-            List<Tuple<String, Float>> nodeWeights = explain ? new ArrayList<>() : null;
-            for (ModelNode node : nodes.values()) {
-                if (node.containsShard(shard) && explain == false) {
-                    // decision is NO without needing to check anything further, so short circuit
-                    continue;
-                }
-
-                // weight of this index currently on the node
-                float currentWeight = weight.weightWithAllocationConstraints(this, node, shard.getIndexName());
-                // moving the shard would not improve the balance, and we are not in explain mode, so short circuit
-                if (currentWeight > minWeight && explain == false) {
-                    continue;
-                }
-
-                Decision currentDecision = allocation.deciders().canAllocate(shard, node.getRoutingNode(), allocation);
-                if (explain) {
-                    nodeExplanationMap.put(node.getNodeId(), new NodeAllocationResult(node.getRoutingNode().node(), currentDecision, 0));
-                    nodeWeights.add(Tuple.tuple(node.getNodeId(), currentWeight));
-                }
-                if (currentDecision.type() == Type.YES || currentDecision.type() == Type.THROTTLE) {
-                    final boolean updateMinNode;
-                    if (currentWeight == minWeight) {
-                        /*  we have an equal weight tie breaking:
-                         *  1. if one decision is YES prefer it
-                         *  2. prefer the node that holds the primary for this index with the next id in the ring ie.
-                         *  for the 3 shards 2 replica case we try to build up:
-                         *    1 2 0
-                         *    2 0 1
-                         *    0 1 2
-                         *  such that if we need to tie-break we try to prefer the node holding a shard with the minimal id greater
-                         *  than the id of the shard we need to assign. This works find when new indices are created since
-                         *  primaries are added first and we only add one shard set a time in this algorithm.
-                         */
-                        if (currentDecision.type() == decision.type()) {
-                            final int repId = shard.id();
-                            final int nodeHigh = node.highestPrimary(shard.index().getName());
-                            final int minNodeHigh = minNode.highestPrimary(shard.getIndexName());
-                            updateMinNode = ((((nodeHigh > repId && minNodeHigh > repId) || (nodeHigh < repId && minNodeHigh < repId))
-                                && (nodeHigh < minNodeHigh)) || (nodeHigh > repId && minNodeHigh < repId));
-                        } else {
-                            updateMinNode = currentDecision.type() == Type.YES;
-                        }
-                    } else {
-                        updateMinNode = currentWeight < minWeight;
-                    }
-                    if (updateMinNode) {
-                        minNode = node;
-                        minWeight = currentWeight;
-                        decision = currentDecision;
-                    }
-                }
-            }
-            if (decision == null) {
-                // decision was not set and a node was not assigned, so treat it as a NO decision
-                decision = Decision.NO;
-            }
-            List<NodeAllocationResult> nodeDecisions = null;
-            if (explain) {
-                nodeDecisions = new ArrayList<>();
-                // fill in the correct weight ranking, once we've been through all nodes
-                nodeWeights.sort((nodeWeight1, nodeWeight2) -> Float.compare(nodeWeight1.v2(), nodeWeight2.v2()));
-                int weightRanking = 0;
-                for (Tuple<String, Float> nodeWeight : nodeWeights) {
-                    NodeAllocationResult current = nodeExplanationMap.get(nodeWeight.v1());
-                    nodeDecisions.add(new NodeAllocationResult(current.getNode(), current.getCanAllocateDecision(), ++weightRanking));
-                }
-            }
-            return AllocateUnassignedDecision.fromDecision(decision, minNode != null ? minNode.routingNode.node() : null, nodeDecisions);
-        }
-
-        private static final Comparator<ShardRouting> BY_DESCENDING_SHARD_ID = Comparator.comparing(ShardRouting::shardId).reversed();
-
-        /**
-         * Tries to find a relocation from the max node to the minimal node for an arbitrary shard of the given index on the
-         * balance model. Iff this method returns a <code>true</code> the relocation has already been executed on the
-         * simulation model as well as on the cluster.
-         */
-        private boolean tryRelocateShard(ModelNode minNode, ModelNode maxNode, String idx) {
-            final ModelIndex index = maxNode.getIndex(idx);
-            if (index != null) {
-                logger.trace("Try relocating shard of [{}] from [{}] to [{}]", idx, maxNode.getNodeId(), minNode.getNodeId());
-                final Iterable<ShardRouting> shardRoutings = StreamSupport.stream(index.spliterator(), false)
-                    .filter(ShardRouting::started) // cannot rebalance unassigned, initializing or relocating shards anyway
-                    .filter(maxNode::containsShard)
-                    .sorted(BY_DESCENDING_SHARD_ID) // check in descending order of shard id so that the decision is deterministic
-                ::iterator;
-
-                final AllocationDeciders deciders = allocation.deciders();
-                for (ShardRouting shard : shardRoutings) {
-                    final Decision rebalanceDecision = deciders.canRebalance(shard, allocation);
-                    if (rebalanceDecision.type() == Type.NO) {
-                        continue;
-                    }
-                    final Decision allocationDecision = deciders.canAllocate(shard, minNode.getRoutingNode(), allocation);
-                    if (allocationDecision.type() == Type.NO) {
-                        continue;
-                    }
-
-                    final Decision decision = new Decision.Multi().add(allocationDecision).add(rebalanceDecision);
-
-                    maxNode.removeShard(shard);
-                    long shardSize = allocation.clusterInfo().getShardSize(shard, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE);
-
-                    if (decision.type() == Type.YES) {
-                        /* only allocate on the cluster if we are not throttled */
-                        logger.debug("Relocate [{}] from [{}] to [{}]", shard, maxNode.getNodeId(), minNode.getNodeId());
-                        minNode.addShard(routingNodes.relocateShard(shard, minNode.getNodeId(), shardSize, allocation.changes()).v1());
-                        return true;
-                    } else {
-                        /* allocate on the model even if throttled */
-                        logger.debug("Simulate relocation of [{}] from [{}] to [{}]", shard, maxNode.getNodeId(), minNode.getNodeId());
-                        assert decision.type() == Type.THROTTLE;
-                        minNode.addShard(shard.relocate(minNode.getNodeId(), shardSize));
-                        return false;
-                    }
-                }
-            }
-            logger.trace("No shards of [{}] can relocate from [{}] to [{}]", idx, maxNode.getNodeId(), minNode.getNodeId());
-            return false;
-        }
-
     }
 
+    /**
+     * A model node.
+     *
+     * @opensearch.internal
+     */
     public static class ModelNode implements Iterable<ModelIndex> {
         private final Map<String, ModelIndex> indices = new HashMap<>();
         private int numShards = 0;
@@ -1220,6 +423,15 @@ public int numShards(String idx) {
             return index == null ? 0 : index.numShards();
         }
 
+        public int numPrimaryShards(String idx) {
+            ModelIndex index = indices.get(idx);
+            return index == null ? 0 : index.numPrimaryShards();
+        }
+
+        public int numPrimaryShards() {
+            return indices.values().stream().mapToInt(index -> index.numPrimaryShards()).sum();
+        }
+
         public int highestPrimary(String index) {
             ModelIndex idx = indices.get(index);
             if (idx != null) {
@@ -1265,18 +477,47 @@ public boolean containsShard(ShardRouting shard) {
             ModelIndex index = getIndex(shard.getIndexName());
             return index == null ? false : index.containsShard(shard);
         }
+    }
 
+    /**
+     *  A {@link Balancer} used by the {@link BalancedShardsAllocator} to perform allocation operations
+     * @deprecated As of 2.4.0, replaced by {@link LocalShardsBalancer}
+     *
+     * @opensearch.internal
+     */
+    @Deprecated
+    public static class Balancer extends LocalShardsBalancer {
+        public Balancer(
+            Logger logger,
+            RoutingAllocation allocation,
+            ShardMovementStrategy shardMovementStrategy,
+            BalancedShardsAllocator.WeightFunction weight,
+            float threshold,
+            boolean preferPrimaryBalance
+        ) {
+            super(logger, allocation, shardMovementStrategy, weight, threshold, preferPrimaryBalance);
+        }
     }
 
+    /**
+     * A model index.
+     *
+     * @opensearch.internal
+     */
     static final class ModelIndex implements Iterable<ShardRouting> {
         private final String id;
         private final Set<ShardRouting> shards = new HashSet<>(4); // expect few shards of same index to be allocated on same node
+        private final Set<ShardRouting> primaryShards = new HashSet<>();
         private int highestPrimary = -1;
 
         ModelIndex(String id) {
             this.id = id;
         }
 
+        public int numPrimaryShards() {
+            return primaryShards.size();
+        }
+
         public int highestPrimary() {
             if (highestPrimary == -1) {
                 int maxId = -1;
@@ -1306,12 +547,20 @@ public Iterator<ShardRouting> iterator() {
         public void removeShard(ShardRouting shard) {
             highestPrimary = -1;
             assert shards.contains(shard) : "Shard not allocated on current node: " + shard;
+            if (shard.primary()) {
+                assert primaryShards.contains(shard) : "Primary shard not allocated on current node: " + shard;
+                primaryShards.remove(shard);
+            }
             shards.remove(shard);
         }
 
         public void addShard(ShardRouting shard) {
             highestPrimary = -1;
-            assert !shards.contains(shard) : "Shard already allocated on current node: " + shard;
+            assert shards.contains(shard) == false : "Shard already allocated on current node: " + shard;
+            if (shard.primary()) {
+                assert primaryShards.contains(shard) == false : "Primary shard already allocated on current node: " + shard;
+                primaryShards.add(shard);
+            }
             shards.add(shard);
         }
 
@@ -1320,6 +569,11 @@ public boolean containsShard(ShardRouting shard) {
         }
     }
 
+    /**
+     * A node sorter.
+     *
+     * @opensearch.internal
+     */
     static final class NodeSorter extends IntroSorter {
 
         final ModelNode[] modelNodes;
@@ -1327,10 +581,10 @@ static final class NodeSorter extends IntroSorter {
         final float[] weights;
         private final WeightFunction function;
         private String index;
-        private final Balancer balancer;
+        private final ShardsBalancer balancer;
         private float pivotWeight;
 
-        NodeSorter(ModelNode[] modelNodes, WeightFunction function, Balancer balancer) {
+        NodeSorter(ModelNode[] modelNodes, WeightFunction function, ShardsBalancer balancer) {
             this.function = function;
             this.balancer = balancer;
             this.modelNodes = modelNodes;
@@ -1354,7 +608,7 @@ public void reset(String index) {
         }
 
         public float weight(ModelNode node) {
-            return function.weight(balancer, node, index);
+            return function.weightWithRebalanceConstraints(balancer, node, index);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/LocalShardsBalancer.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/LocalShardsBalancer.java
new file mode 100644
index 0000000000000..fd87fd3d93600
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/LocalShardsBalancer.java
@@ -0,0 +1,1031 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation.allocator;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.util.ArrayUtil;
+import org.apache.lucene.util.IntroSorter;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingPool;
+import org.opensearch.cluster.routing.ShardMovementStrategy;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.routing.allocation.AllocateUnassignedDecision;
+import org.opensearch.cluster.routing.allocation.AllocationDecision;
+import org.opensearch.cluster.routing.allocation.MoveDecision;
+import org.opensearch.cluster.routing.allocation.NodeAllocationResult;
+import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
+import org.opensearch.cluster.routing.allocation.decider.Decision;
+import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.gateway.PriorityComparator;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
+
+/**
+ * A {@link LocalShardsBalancer} used by the {@link BalancedShardsAllocator} to perform allocation operations
+ * for local shards within the cluster.
+ *
+ * @opensearch.internal
+ */
+public class LocalShardsBalancer extends ShardsBalancer {
+    private final Logger logger;
+    private final Map<String, BalancedShardsAllocator.ModelNode> nodes;
+    private final RoutingAllocation allocation;
+    private final RoutingNodes routingNodes;
+    private final ShardMovementStrategy shardMovementStrategy;
+
+    private final boolean preferPrimaryBalance;
+    private final BalancedShardsAllocator.WeightFunction weight;
+
+    private final float threshold;
+    private final Metadata metadata;
+    private final float avgShardsPerNode;
+
+    private final float avgPrimaryShardsPerNode;
+    private final BalancedShardsAllocator.NodeSorter sorter;
+    private final Set<RoutingNode> inEligibleTargetNode;
+
+    public LocalShardsBalancer(
+        Logger logger,
+        RoutingAllocation allocation,
+        ShardMovementStrategy shardMovementStrategy,
+        BalancedShardsAllocator.WeightFunction weight,
+        float threshold,
+        boolean preferPrimaryBalance
+    ) {
+        this.logger = logger;
+        this.allocation = allocation;
+        this.weight = weight;
+        this.threshold = threshold;
+        this.routingNodes = allocation.routingNodes();
+        this.metadata = allocation.metadata();
+        avgShardsPerNode = ((float) metadata.getTotalNumberOfShards()) / routingNodes.size();
+        avgPrimaryShardsPerNode = (float) (StreamSupport.stream(metadata.spliterator(), false)
+            .mapToInt(IndexMetadata::getNumberOfShards)
+            .sum()) / routingNodes.size();
+        nodes = Collections.unmodifiableMap(buildModelFromAssigned());
+        sorter = newNodeSorter();
+        inEligibleTargetNode = new HashSet<>();
+        this.preferPrimaryBalance = preferPrimaryBalance;
+        this.shardMovementStrategy = shardMovementStrategy;
+    }
+
+    /**
+     * Returns an array view on the nodes in the balancer. Nodes should not be removed from this list.
+     */
+    private BalancedShardsAllocator.ModelNode[] nodesArray() {
+        return nodes.values().toArray(new BalancedShardsAllocator.ModelNode[nodes.size()]);
+    }
+
+    /**
+     * Returns the average of shards per node for the given index
+     */
+    @Override
+    public float avgShardsPerNode(String index) {
+        return ((float) metadata.index(index).getTotalNumberOfShards()) / nodes.size();
+    }
+
+    @Override
+    public float avgPrimaryShardsPerNode(String index) {
+        return ((float) metadata.index(index).getNumberOfShards()) / nodes.size();
+    }
+
+    @Override
+    public float avgPrimaryShardsPerNode() {
+        return avgPrimaryShardsPerNode;
+    }
+
+    /**
+     * Returns the global average of shards per node
+     */
+    @Override
+    public float avgShardsPerNode() {
+        float totalShards = nodes.values().stream().map(BalancedShardsAllocator.ModelNode::numShards).reduce(0, Integer::sum);
+        return totalShards / nodes.size();
+    }
+
+    /**
+     * Returns a new {@link BalancedShardsAllocator.NodeSorter} that sorts the nodes based on their
+     * current weight with respect to the index passed to the sorter. The
+     * returned sorter is not sorted. Use {@link BalancedShardsAllocator.NodeSorter#reset(String)}
+     * to sort based on an index.
+     */
+    private BalancedShardsAllocator.NodeSorter newNodeSorter() {
+        return new BalancedShardsAllocator.NodeSorter(nodesArray(), weight, this);
+    }
+
+    /**
+     * The absolute value difference between two weights.
+     */
+    private static float absDelta(float lower, float higher) {
+        assert higher >= lower : higher + " lt " + lower + " but was expected to be gte";
+        return Math.abs(higher - lower);
+    }
+
+    /**
+     * Returns {@code true} iff the weight delta between two nodes is under a defined threshold.
+     * See {@link BalancedShardsAllocator#THRESHOLD_SETTING} for defining the threshold.
+     */
+    private static boolean lessThan(float delta, float threshold) {
+        /* deltas close to the threshold are "rounded" to the threshold manually
+           to prevent floating point problems if the delta is very close to the
+           threshold ie. 1.000000002 which can trigger unnecessary balance actions*/
+        return delta <= (threshold + 0.001f);
+    }
+
+    /**
+     * Balances the nodes on the cluster model according to the weight function.
+     * The actual balancing is delegated to {@link #balanceByWeights()}
+     */
+    @Override
+    void balance() {
+        if (logger.isTraceEnabled()) {
+            logger.trace("Start balancing cluster");
+        }
+        if (allocation.hasPendingAsyncFetch()) {
+            /*
+             * see https://github.com/elastic/elasticsearch/issues/14387
+             * if we allow rebalance operations while we are still fetching shard store data
+             * we might end up with unnecessary rebalance operations which can be super confusion/frustrating
+             * since once the fetches come back we might just move all the shards back again.
+             * Therefore we only do a rebalance if we have fetched all information.
+             */
+            logger.debug("skipping rebalance due to in-flight shard/store fetches");
+            return;
+        }
+        if (allocation.deciders().canRebalance(allocation).type() != Decision.Type.YES) {
+            logger.trace("skipping rebalance as it is disabled");
+            return;
+        }
+        if (nodes.size() < 2) { /* skip if we only have one node */
+            logger.trace("skipping rebalance as single node only");
+            return;
+        }
+        balanceByWeights();
+    }
+
+    /**
+     * Makes a decision about moving a single shard to a different node to form a more
+     * optimally balanced cluster.  This method is invoked from the cluster allocation
+     * explain API only.
+     */
+    @Override
+    MoveDecision decideRebalance(final ShardRouting shard) {
+        if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation))) {
+            return MoveDecision.NOT_TAKEN;
+        }
+
+        if (shard.started() == false) {
+            // we can only rebalance started shards
+            return MoveDecision.NOT_TAKEN;
+        }
+
+        Decision canRebalance = allocation.deciders().canRebalance(shard, allocation);
+
+        sorter.reset(shard.getIndexName());
+        BalancedShardsAllocator.ModelNode[] modelNodes = sorter.modelNodes;
+        final String currentNodeId = shard.currentNodeId();
+        // find currently assigned node
+        BalancedShardsAllocator.ModelNode currentNode = null;
+        for (BalancedShardsAllocator.ModelNode node : modelNodes) {
+            if (node.getNodeId().equals(currentNodeId)) {
+                currentNode = node;
+                break;
+            }
+        }
+        assert currentNode != null : "currently assigned node could not be found";
+
+        // balance the shard, if a better node can be found
+        final String idxName = shard.getIndexName();
+        final float currentWeight = weight.weight(this, currentNode, idxName);
+        final AllocationDeciders deciders = allocation.deciders();
+        Decision.Type rebalanceDecisionType = Decision.Type.NO;
+        BalancedShardsAllocator.ModelNode assignedNode = null;
+        List<Tuple<BalancedShardsAllocator.ModelNode, Decision>> betterBalanceNodes = new ArrayList<>();
+        List<Tuple<BalancedShardsAllocator.ModelNode, Decision>> sameBalanceNodes = new ArrayList<>();
+        List<Tuple<BalancedShardsAllocator.ModelNode, Decision>> worseBalanceNodes = new ArrayList<>();
+        for (BalancedShardsAllocator.ModelNode node : modelNodes) {
+            if (node == currentNode) {
+                continue; // skip over node we're currently allocated to
+            }
+            final Decision canAllocate = deciders.canAllocate(shard, node.getRoutingNode(), allocation);
+            // the current weight of the node in the cluster, as computed by the weight function;
+            // this is a comparison of the number of shards on this node to the number of shards
+            // that should be on each node on average (both taking the cluster as a whole into account
+            // as well as shards per index)
+            final float nodeWeight = weight.weightWithRebalanceConstraints(this, node, idxName);
+            // if the node we are examining has a worse (higher) weight than the node the shard is
+            // assigned to, then there is no way moving the shard to the node with the worse weight
+            // can make the balance of the cluster better, so we check for that here
+            final boolean betterWeightThanCurrent = nodeWeight <= currentWeight;
+            boolean rebalanceConditionsMet = false;
+            if (betterWeightThanCurrent) {
+                // get the delta between the weights of the node we are checking and the node that holds the shard
+                float currentDelta = absDelta(nodeWeight, currentWeight);
+                // checks if the weight delta is above a certain threshold; if it is not above a certain threshold,
+                // then even though the node we are examining has a better weight and may make the cluster balance
+                // more even, it doesn't make sense to execute the heavyweight operation of relocating a shard unless
+                // the gains make it worth it, as defined by the threshold
+                boolean deltaAboveThreshold = lessThan(currentDelta, threshold) == false;
+                // calculate the delta of the weights of the two nodes if we were to add the shard to the
+                // node in question and move it away from the node that currently holds it.
+                // hence we add 2.0f to the weight delta
+                float proposedDelta = 2.0f + nodeWeight - currentWeight;
+                boolean betterWeightWithShardAdded = proposedDelta < currentDelta;
+
+                rebalanceConditionsMet = deltaAboveThreshold && betterWeightWithShardAdded;
+                // if the simulated weight delta with the shard moved away is better than the weight delta
+                // with the shard remaining on the current node, and we are allowed to allocate to the
+                // node in question, then allow the rebalance
+                if (rebalanceConditionsMet && canAllocate.type().higherThan(rebalanceDecisionType)) {
+                    // rebalance to the node, only will get overwritten if the decision here is to
+                    // THROTTLE and we get a decision with YES on another node
+                    rebalanceDecisionType = canAllocate.type();
+                    assignedNode = node;
+                }
+            }
+            Tuple<BalancedShardsAllocator.ModelNode, Decision> nodeResult = Tuple.tuple(node, canAllocate);
+            if (rebalanceConditionsMet) {
+                betterBalanceNodes.add(nodeResult);
+            } else if (betterWeightThanCurrent) {
+                sameBalanceNodes.add(nodeResult);
+            } else {
+                worseBalanceNodes.add(nodeResult);
+            }
+        }
+
+        int weightRanking = 0;
+        List<NodeAllocationResult> nodeDecisions = new ArrayList<>(modelNodes.length - 1);
+        for (Tuple<BalancedShardsAllocator.ModelNode, Decision> result : betterBalanceNodes) {
+            nodeDecisions.add(
+                new NodeAllocationResult(
+                    result.v1().getRoutingNode().node(),
+                    AllocationDecision.fromDecisionType(result.v2().type()),
+                    result.v2(),
+                    ++weightRanking
+                )
+            );
+        }
+        int currentNodeWeightRanking = ++weightRanking;
+        for (Tuple<BalancedShardsAllocator.ModelNode, Decision> result : sameBalanceNodes) {
+            AllocationDecision nodeDecision = result.v2().type() == Decision.Type.NO
+                ? AllocationDecision.NO
+                : AllocationDecision.WORSE_BALANCE;
+            nodeDecisions.add(
+                new NodeAllocationResult(result.v1().getRoutingNode().node(), nodeDecision, result.v2(), currentNodeWeightRanking)
+            );
+        }
+        for (Tuple<BalancedShardsAllocator.ModelNode, Decision> result : worseBalanceNodes) {
+            AllocationDecision nodeDecision = result.v2().type() == Decision.Type.NO
+                ? AllocationDecision.NO
+                : AllocationDecision.WORSE_BALANCE;
+            nodeDecisions.add(new NodeAllocationResult(result.v1().getRoutingNode().node(), nodeDecision, result.v2(), ++weightRanking));
+        }
+
+        if (canRebalance.type() != Decision.Type.YES || allocation.hasPendingAsyncFetch()) {
+            AllocationDecision allocationDecision = allocation.hasPendingAsyncFetch()
+                ? AllocationDecision.AWAITING_INFO
+                : AllocationDecision.fromDecisionType(canRebalance.type());
+            return MoveDecision.cannotRebalance(canRebalance, allocationDecision, currentNodeWeightRanking, nodeDecisions);
+        } else {
+            return MoveDecision.rebalance(
+                canRebalance,
+                AllocationDecision.fromDecisionType(rebalanceDecisionType),
+                assignedNode != null ? assignedNode.getRoutingNode().node() : null,
+                currentNodeWeightRanking,
+                nodeDecisions
+            );
+        }
+    }
+
+    /**
+     * Balances the nodes on the cluster model according to the weight
+     * function. The configured threshold is the minimum delta between the
+     * weight of the maximum node and the minimum node according to the
+     * {@link BalancedShardsAllocator.WeightFunction}. This weight is calculated per index to
+     * distribute shards evenly per index. The balancer tries to relocate
+     * shards only if the delta exceeds the threshold. In the default case
+     * the threshold is set to {@code 1.0} to enforce gaining relocation
+     * only, or in other words relocations that move the weight delta closer
+     * to {@code 0.0}
+     */
+    private void balanceByWeights() {
+        final AllocationDeciders deciders = allocation.deciders();
+        final BalancedShardsAllocator.ModelNode[] modelNodes = sorter.modelNodes;
+        final float[] weights = sorter.weights;
+        for (String index : buildWeightOrderedIndices()) {
+            IndexMetadata indexMetadata = metadata.index(index);
+
+            // find nodes that have a shard of this index or where shards of this index are allowed to be allocated to,
+            // move these nodes to the front of modelNodes so that we can only balance based on these nodes
+            int relevantNodes = 0;
+            for (int i = 0; i < modelNodes.length; i++) {
+                BalancedShardsAllocator.ModelNode modelNode = modelNodes[i];
+                if (modelNode.getIndex(index) != null
+                    || deciders.canAllocate(indexMetadata, modelNode.getRoutingNode(), allocation).type() != Decision.Type.NO) {
+                    // swap nodes at position i and relevantNodes
+                    modelNodes[i] = modelNodes[relevantNodes];
+                    modelNodes[relevantNodes] = modelNode;
+                    relevantNodes++;
+                }
+            }
+
+            if (relevantNodes < 2) {
+                continue;
+            }
+
+            sorter.reset(index, 0, relevantNodes);
+            int lowIdx = 0;
+            int highIdx = relevantNodes - 1;
+            while (true) {
+                final BalancedShardsAllocator.ModelNode minNode = modelNodes[lowIdx];
+                final BalancedShardsAllocator.ModelNode maxNode = modelNodes[highIdx];
+                advance_range: if (maxNode.numShards(index) > 0) {
+                    final float delta = absDelta(weights[lowIdx], weights[highIdx]);
+                    if (lessThan(delta, threshold)) {
+                        if (lowIdx > 0
+                            && highIdx - 1 > 0 // is there a chance for a higher delta?
+                            && (absDelta(weights[0], weights[highIdx - 1]) > threshold) // check if we need to break at all
+                        ) {
+                            /* This is a special case if allocations from the "heaviest" to the "lighter" nodes is not possible
+                             * due to some allocation decider restrictions like zone awareness. if one zone has for instance
+                             * less nodes than another zone. so one zone is horribly overloaded from a balanced perspective but we
+                             * can't move to the "lighter" shards since otherwise the zone would go over capacity.
+                             *
+                             * This break jumps straight to the condition below were we start moving from the high index towards
+                             * the low index to shrink the window we are considering for balance from the other direction.
+                             * (check shrinking the window from MAX to MIN)
+                             * See #3580
+                             */
+                            break advance_range;
+                        }
+                        if (logger.isTraceEnabled()) {
+                            logger.trace(
+                                "Stop balancing index [{}]  min_node [{}] weight: [{}]" + "  max_node [{}] weight: [{}]  delta: [{}]",
+                                index,
+                                maxNode.getNodeId(),
+                                weights[highIdx],
+                                minNode.getNodeId(),
+                                weights[lowIdx],
+                                delta
+                            );
+                        }
+                        break;
+                    }
+                    if (logger.isTraceEnabled()) {
+                        logger.trace(
+                            "Balancing from node [{}] weight: [{}] to node [{}] weight: [{}]  delta: [{}]",
+                            maxNode.getNodeId(),
+                            weights[highIdx],
+                            minNode.getNodeId(),
+                            weights[lowIdx],
+                            delta
+                        );
+                    }
+                    if (delta <= 1.0f) {
+                        /*
+                         * prevent relocations that only swap the weights of the two nodes. a relocation must bring us closer to the
+                         * balance if we only achieve the same delta the relocation is useless
+                         *
+                         * NB this comment above was preserved from an earlier version but doesn't obviously describe the code today. We
+                         * already know that lessThan(delta, threshold) == false and threshold defaults to 1.0, so by default we never
+                         * hit this case anyway.
+                         */
+                        logger.trace(
+                            "Couldn't find shard to relocate from node [{}] to node [{}]",
+                            maxNode.getNodeId(),
+                            minNode.getNodeId()
+                        );
+                    } else if (tryRelocateShard(minNode, maxNode, index)) {
+                        /*
+                         * TODO we could be a bit smarter here, we don't need to fully sort necessarily
+                         * we could just find the place to insert linearly but the win might be minor
+                         * compared to the added complexity
+                         */
+                        weights[lowIdx] = sorter.weight(modelNodes[lowIdx]);
+                        weights[highIdx] = sorter.weight(modelNodes[highIdx]);
+                        sorter.sort(0, relevantNodes);
+                        lowIdx = 0;
+                        highIdx = relevantNodes - 1;
+                        continue;
+                    }
+                }
+                if (lowIdx < highIdx - 1) {
+                    /* Shrinking the window from MIN to MAX
+                     * we can't move from any shard from the min node lets move on to the next node
+                     * and see if the threshold still holds. We either don't have any shard of this
+                     * index on this node of allocation deciders prevent any relocation.*/
+                    lowIdx++;
+                } else if (lowIdx > 0) {
+                    /* Shrinking the window from MAX to MIN
+                     * now we go max to min since obviously we can't move anything to the max node
+                     * lets pick the next highest */
+                    lowIdx = 0;
+                    highIdx--;
+                } else {
+                    /* we are done here, we either can't relocate anymore or we are balanced */
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * This builds a initial index ordering where the indices are returned
+     * in most unbalanced first. We need this in order to prevent over
+     * allocations on added nodes from one index when the weight parameters
+     * for global balance overrule the index balance at an intermediate
+     * state. For example this can happen if we have 3 nodes and 3 indices
+     * with 3 primary and 1 replica shards. At the first stage all three nodes hold
+     * 2 shard for each index. Now we add another node and the first index
+     * is balanced moving three shards from two of the nodes over to the new node since it
+     * has no shards yet and global balance for the node is way below
+     * average. To re-balance we need to move shards back eventually likely
+     * to the nodes we relocated them from.
+     */
+    private String[] buildWeightOrderedIndices() {
+
+        final List<String> localIndices = new ArrayList<>();
+        for (String index : allocation.routingTable().indicesRouting().keySet().toArray(new String[0])) {
+            if (RoutingPool.LOCAL_ONLY.equals(RoutingPool.getIndexPool(metadata.index(index)))) {
+                localIndices.add(index);
+            }
+        }
+        final String[] indices = localIndices.toArray(new String[0]);
+
+        final float[] deltas = new float[indices.length];
+        for (int i = 0; i < deltas.length; i++) {
+            sorter.reset(indices[i]);
+            deltas[i] = sorter.delta();
+        }
+        new IntroSorter() {
+
+            float pivotWeight;
+
+            @Override
+            protected void swap(int i, int j) {
+                final String tmpIdx = indices[i];
+                indices[i] = indices[j];
+                indices[j] = tmpIdx;
+                final float tmpDelta = deltas[i];
+                deltas[i] = deltas[j];
+                deltas[j] = tmpDelta;
+            }
+
+            @Override
+            protected int compare(int i, int j) {
+                return Float.compare(deltas[j], deltas[i]);
+            }
+
+            @Override
+            protected void setPivot(int i) {
+                pivotWeight = deltas[i];
+            }
+
+            @Override
+            protected int comparePivot(int j) {
+                return Float.compare(deltas[j], pivotWeight);
+            }
+        }.sort(0, deltas.length);
+
+        return indices;
+    }
+
+    /**
+     * Checks if target node is ineligible and if so, adds to the list
+     * of ineligible target nodes
+     */
+    private void checkAndAddInEligibleTargetNode(RoutingNode targetNode) {
+        Decision nodeLevelAllocationDecision = allocation.deciders().canAllocateAnyShardToNode(targetNode, allocation);
+        if (nodeLevelAllocationDecision.type() != Decision.Type.YES) {
+            inEligibleTargetNode.add(targetNode);
+        }
+    }
+
+    /**
+     * Move started shards that can not be allocated to a node anymore
+     *
+     * For each shard to be moved this function executes a move operation
+     * to the minimal eligible node with respect to the
+     * weight function. If a shard is moved the shard will be set to
+     * {@link ShardRoutingState#RELOCATING} and a shadow instance of this
+     * shard is created with an incremented version in the state
+     * {@link ShardRoutingState#INITIALIZING}.
+     */
+    @Override
+    void moveShards() {
+        // Iterate over the started shards interleaving between nodes, and check if they can remain. In the presence of throttling
+        // shard movements, the goal of this iteration order is to achieve a fairer movement of shards from the nodes that are
+        // offloading the shards.
+
+        // Trying to eliminate target nodes so that we do not unnecessarily iterate over source nodes
+        // when no target is eligible
+        for (BalancedShardsAllocator.ModelNode currentNode : sorter.modelNodes) {
+            checkAndAddInEligibleTargetNode(currentNode.getRoutingNode());
+        }
+        boolean primariesThrottled = false;
+        for (Iterator<ShardRouting> it = allocation.routingNodes().nodeInterleavedShardIterator(shardMovementStrategy); it.hasNext();) {
+            // Verify if the cluster concurrent recoveries have been reached.
+            if (allocation.deciders().canMoveAnyShard(allocation).type() != Decision.Type.YES) {
+                logger.info(
+                    "Cannot move any shard in the cluster due to cluster concurrent recoveries getting breached"
+                        + ". Skipping shard iteration"
+                );
+                return;
+            }
+            // Early terminate node interleaved shard iteration when no eligible target nodes are available
+            if (sorter.modelNodes.length == inEligibleTargetNode.size()) {
+                logger.info(
+                    "Cannot move any shard in the cluster as there is no node on which shards can be allocated"
+                        + ". Skipping shard iteration"
+                );
+                return;
+            }
+
+            ShardRouting shardRouting = it.next();
+
+            if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shardRouting, allocation))) {
+                continue;
+            }
+
+            // Ensure that replicas don't relocate if primaries are being throttled and primary first shard movement strategy is enabled
+            if ((shardMovementStrategy == ShardMovementStrategy.PRIMARY_FIRST) && primariesThrottled && !shardRouting.primary()) {
+                logger.info(
+                    "Cannot move any replica shard in the cluster as movePrimaryFirst is enabled and primary shards"
+                        + "are being throttled. Skipping shard iteration"
+                );
+                return;
+            }
+
+            // Verify if the shard is allowed to move if outgoing recovery on the node hosting the primary shard
+            // is not being throttled.
+            Decision canMoveAwayDecision = allocation.deciders().canMoveAway(shardRouting, allocation);
+            if (canMoveAwayDecision.type() != Decision.Type.YES) {
+                if (logger.isDebugEnabled()) logger.debug("Cannot move away shard [{}] Skipping this shard", shardRouting);
+                if (shardRouting.primary() && canMoveAwayDecision.type() == Decision.Type.THROTTLE) {
+                    primariesThrottled = true;
+                }
+                continue;
+            }
+
+            final MoveDecision moveDecision = decideMove(shardRouting);
+            if (moveDecision.isDecisionTaken() && moveDecision.forceMove()) {
+                final BalancedShardsAllocator.ModelNode sourceNode = nodes.get(shardRouting.currentNodeId());
+                final BalancedShardsAllocator.ModelNode targetNode = nodes.get(moveDecision.getTargetNode().getId());
+                sourceNode.removeShard(shardRouting);
+                Tuple<ShardRouting, ShardRouting> relocatingShards = routingNodes.relocateShard(
+                    shardRouting,
+                    targetNode.getNodeId(),
+                    allocation.clusterInfo().getShardSize(shardRouting, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE),
+                    allocation.changes()
+                );
+                targetNode.addShard(relocatingShards.v2());
+                if (logger.isTraceEnabled()) {
+                    logger.trace("Moved shard [{}] to node [{}]", shardRouting, targetNode.getRoutingNode());
+                }
+
+                // Verifying if this node can be considered ineligible for further iterations
+                if (targetNode != null) {
+                    checkAndAddInEligibleTargetNode(targetNode.getRoutingNode());
+                }
+            } else if (moveDecision.isDecisionTaken() && moveDecision.canRemain() == false) {
+                logger.trace("[{}][{}] can't move", shardRouting.index(), shardRouting.id());
+            }
+        }
+    }
+
+    /**
+     * Makes a decision on whether to move a started shard to another node.  The following rules apply
+     * to the {@link MoveDecision} return object:
+     *   1. If the shard is not started, no decision will be taken and {@link MoveDecision#isDecisionTaken()} will return false.
+     *   2. If the shard is allowed to remain on its current node, no attempt will be made to move the shard and
+     *      {@link MoveDecision#getCanRemainDecision} will have a decision type of YES.  All other fields in the object will be null.
+     *   3. If the shard is not allowed to remain on its current node, then {@link MoveDecision#getAllocationDecision()} will be
+     *      populated with the decision of moving to another node.  If {@link MoveDecision#forceMove()} ()} returns {@code true}, then
+     *      {@link MoveDecision#getTargetNode} will return a non-null value, otherwise the assignedNodeId will be null.
+     *   4. If the method is invoked in explain mode (e.g. from the cluster allocation explain APIs), then
+     *      {@link MoveDecision#getNodeDecisions} will have a non-null value.
+     */
+    @Override
+    MoveDecision decideMove(final ShardRouting shardRouting) {
+        if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shardRouting, allocation))) {
+            return MoveDecision.NOT_TAKEN;
+        }
+
+        if (shardRouting.started() == false) {
+            // we can only move started shards
+            return MoveDecision.NOT_TAKEN;
+        }
+
+        final boolean explain = allocation.debugDecision();
+        final BalancedShardsAllocator.ModelNode sourceNode = nodes.get(shardRouting.currentNodeId());
+        assert sourceNode != null && sourceNode.containsShard(shardRouting);
+        RoutingNode routingNode = sourceNode.getRoutingNode();
+        Decision canRemain = allocation.deciders().canRemain(shardRouting, routingNode, allocation);
+        if (canRemain.type() != Decision.Type.NO) {
+            return MoveDecision.stay(canRemain);
+        }
+
+        sorter.reset(shardRouting.getIndexName());
+        /*
+         * the sorter holds the minimum weight node first for the shards index.
+         * We now walk through the nodes until we find a node to allocate the shard.
+         * This is not guaranteed to be balanced after this operation we still try best effort to
+         * allocate on the minimal eligible node.
+         */
+        Decision.Type bestDecision = Decision.Type.NO;
+        RoutingNode targetNode = null;
+        final List<NodeAllocationResult> nodeExplanationMap = explain ? new ArrayList<>() : null;
+        int weightRanking = 0;
+        int targetNodeProcessed = 0;
+        for (BalancedShardsAllocator.ModelNode currentNode : sorter.modelNodes) {
+            if (currentNode != sourceNode) {
+                RoutingNode target = currentNode.getRoutingNode();
+                if (!explain && inEligibleTargetNode.contains(target)) continue;
+                // don't use canRebalance as we want hard filtering rules to apply. See #17698
+                if (!explain) {
+                    // If we cannot allocate any shard to node marking it in eligible
+                    Decision nodeLevelAllocationDecision = allocation.deciders().canAllocateAnyShardToNode(target, allocation);
+                    if (nodeLevelAllocationDecision.type() != Decision.Type.YES) {
+                        inEligibleTargetNode.add(currentNode.getRoutingNode());
+                        continue;
+                    }
+                }
+                targetNodeProcessed++;
+                // don't use canRebalance as we want hard filtering rules to apply. See #17698
+                Decision allocationDecision = allocation.deciders().canAllocate(shardRouting, target, allocation);
+                if (explain) {
+                    nodeExplanationMap.add(
+                        new NodeAllocationResult(currentNode.getRoutingNode().node(), allocationDecision, ++weightRanking)
+                    );
+                }
+                // TODO maybe we can respect throttling here too?
+                if (allocationDecision.type().higherThan(bestDecision)) {
+                    bestDecision = allocationDecision.type();
+                    if (bestDecision == Decision.Type.YES) {
+                        targetNode = target;
+                        if (explain == false) {
+                            // we are not in explain mode and already have a YES decision on the best weighted node,
+                            // no need to continue iterating
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+
+        return MoveDecision.cannotRemain(
+            canRemain,
+            AllocationDecision.fromDecisionType(bestDecision),
+            targetNode != null ? targetNode.node() : null,
+            nodeExplanationMap
+        );
+    }
+
+    /**
+     * Builds the internal model from all shards in the given
+     * {@link Iterable}. All shards in the {@link Iterable} must be assigned
+     * to a node. This method will skip shards in the state
+     * {@link ShardRoutingState#RELOCATING} since each relocating shard has
+     * a shadow shard in the state {@link ShardRoutingState#INITIALIZING}
+     * on the target node which we respect during the allocation / balancing
+     * process. In short, this method recreates the status-quo in the cluster.
+     */
+    private Map<String, BalancedShardsAllocator.ModelNode> buildModelFromAssigned() {
+        Map<String, BalancedShardsAllocator.ModelNode> nodes = new HashMap<>();
+        for (RoutingNode rn : routingNodes) {
+            BalancedShardsAllocator.ModelNode node = new BalancedShardsAllocator.ModelNode(rn);
+            nodes.put(rn.nodeId(), node);
+            for (ShardRouting shard : rn) {
+                assert rn.nodeId().equals(shard.currentNodeId());
+                /* we skip relocating shards here since we expect an initializing shard with the same id coming in */
+                if (RoutingPool.LOCAL_ONLY.equals(RoutingPool.getShardPool(shard, allocation)) && shard.state() != RELOCATING) {
+                    node.addShard(shard);
+                    if (logger.isTraceEnabled()) {
+                        logger.trace("Assigned shard [{}] to node [{}]", shard, node.getNodeId());
+                    }
+                }
+            }
+        }
+        return nodes;
+    }
+
+    /**
+     * Allocates all given shards on the minimal eligible node for the shards index
+     * with respect to the weight function. All given shards must be unassigned.
+     */
+    @Override
+    void allocateUnassigned() {
+        RoutingNodes.UnassignedShards unassigned = routingNodes.unassigned();
+        assert !nodes.isEmpty();
+        if (logger.isTraceEnabled()) {
+            logger.trace("Start allocating unassigned shards");
+        }
+        if (unassigned.isEmpty()) {
+            return;
+        }
+
+        /*
+         * TODO: We could be smarter here and group the shards by index and then
+         * use the sorter to save some iterations.
+         */
+        final PriorityComparator secondaryComparator = PriorityComparator.getAllocationComparator(allocation);
+        final Comparator<ShardRouting> comparator = (o1, o2) -> {
+            if (o1.primary() ^ o2.primary()) {
+                return o1.primary() ? -1 : 1;
+            }
+            final int indexCmp;
+            if ((indexCmp = o1.getIndexName().compareTo(o2.getIndexName())) == 0) {
+                return o1.getId() - o2.getId();
+            }
+            // this comparator is more expensive than all the others up there
+            // that's why it's added last even though it could be easier to read
+            // if we'd apply it earlier. this comparator will only differentiate across
+            // indices all shards of the same index is treated equally.
+            final int secondary = secondaryComparator.compare(o1, o2);
+            return secondary == 0 ? indexCmp : secondary;
+        };
+        /*
+         * we use 2 arrays and move replicas to the second array once we allocated an identical
+         * replica in the current iteration to make sure all indices get allocated in the same manner.
+         * The arrays are sorted by primaries first and then by index and shard ID so a 2 indices with
+         * 2 replica and 1 shard would look like:
+         * [(0,P,IDX1), (0,P,IDX2), (0,R,IDX1), (0,R,IDX1), (0,R,IDX2), (0,R,IDX2)]
+         * if we allocate for instance (0, R, IDX1) we move the second replica to the secondary array and proceed with
+         * the next replica. If we could not find a node to allocate (0,R,IDX1) we move all it's replicas to ignoreUnassigned.
+         */
+        ShardRouting[] unassignedShards = unassigned.drain();
+        List<ShardRouting> allUnassignedShards = Arrays.stream(unassignedShards).collect(Collectors.toList());
+        List<ShardRouting> localUnassignedShards = allUnassignedShards.stream()
+            .filter(shard -> RoutingPool.LOCAL_ONLY.equals(RoutingPool.getShardPool(shard, allocation)))
+            .collect(Collectors.toList());
+        allUnassignedShards.removeAll(localUnassignedShards);
+        allUnassignedShards.forEach(shard -> routingNodes.unassigned().add(shard));
+        unassignedShards = localUnassignedShards.toArray(new ShardRouting[0]);
+        ShardRouting[] primary = unassignedShards;
+        ShardRouting[] secondary = new ShardRouting[primary.length];
+        int secondaryLength = 0;
+        int primaryLength = primary.length;
+        ArrayUtil.timSort(primary, comparator);
+        do {
+            for (int i = 0; i < primaryLength; i++) {
+                ShardRouting shard = primary[i];
+                final AllocateUnassignedDecision allocationDecision = decideAllocateUnassigned(shard);
+                final String assignedNodeId = allocationDecision.getTargetNode() != null
+                    ? allocationDecision.getTargetNode().getId()
+                    : null;
+                final BalancedShardsAllocator.ModelNode minNode = assignedNodeId != null ? nodes.get(assignedNodeId) : null;
+
+                if (allocationDecision.getAllocationDecision() == AllocationDecision.YES) {
+                    if (logger.isTraceEnabled()) {
+                        logger.trace("Assigned shard [{}] to [{}]", shard, minNode.getNodeId());
+                    }
+
+                    final long shardSize = DiskThresholdDecider.getExpectedShardSize(
+                        shard,
+                        ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE,
+                        allocation.clusterInfo(),
+                        allocation.snapshotShardSizeInfo(),
+                        allocation.metadata(),
+                        allocation.routingTable()
+                    );
+                    shard = routingNodes.initializeShard(shard, minNode.getNodeId(), null, shardSize, allocation.changes());
+                    minNode.addShard(shard);
+                    if (!shard.primary()) {
+                        // copy over the same replica shards to the secondary array so they will get allocated
+                        // in a subsequent iteration, allowing replicas of other shards to be allocated first
+                        while (i < primaryLength - 1 && comparator.compare(primary[i], primary[i + 1]) == 0) {
+                            secondary[secondaryLength++] = primary[++i];
+                        }
+                    }
+                } else {
+                    // did *not* receive a YES decision
+                    if (logger.isTraceEnabled()) {
+                        logger.trace(
+                            "No eligible node found to assign shard [{}] allocation_status [{}]",
+                            shard,
+                            allocationDecision.getAllocationStatus()
+                        );
+                    }
+
+                    if (minNode != null) {
+                        // throttle decision scenario
+                        assert allocationDecision.getAllocationStatus() == UnassignedInfo.AllocationStatus.DECIDERS_THROTTLED;
+                        final long shardSize = DiskThresholdDecider.getExpectedShardSize(
+                            shard,
+                            ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE,
+                            allocation.clusterInfo(),
+                            allocation.snapshotShardSizeInfo(),
+                            allocation.metadata(),
+                            allocation.routingTable()
+                        );
+                        minNode.addShard(shard.initialize(minNode.getNodeId(), null, shardSize));
+                    } else {
+                        if (logger.isTraceEnabled()) {
+                            logger.trace("No Node found to assign shard [{}]", shard);
+                        }
+                    }
+
+                    unassigned.ignoreShard(shard, allocationDecision.getAllocationStatus(), allocation.changes());
+                    if (!shard.primary()) { // we could not allocate it and we are a replica - check if we can ignore the other replicas
+                        while (i < primaryLength - 1 && comparator.compare(primary[i], primary[i + 1]) == 0) {
+                            unassigned.ignoreShard(primary[++i], allocationDecision.getAllocationStatus(), allocation.changes());
+                        }
+                    }
+                }
+            }
+            primaryLength = secondaryLength;
+            ShardRouting[] tmp = primary;
+            primary = secondary;
+            secondary = tmp;
+            secondaryLength = 0;
+        } while (primaryLength > 0);
+        // clear everything we have either added it or moved to ignoreUnassigned
+    }
+
+    /**
+     * Make a decision for allocating an unassigned shard.  This method returns a two values in a tuple: the
+     * first value is the {@link Decision} taken to allocate the unassigned shard, the second value is the
+     * {@link BalancedShardsAllocator.ModelNode} representing the node that the shard should be assigned to.  If the decision returned
+     * is of type {@link Decision.Type#NO}, then the assigned node will be null.
+     */
+    @Override
+    AllocateUnassignedDecision decideAllocateUnassigned(final ShardRouting shard) {
+        if (shard.assignedToNode()) {
+            // we only make decisions for unassigned shards here
+            return AllocateUnassignedDecision.NOT_TAKEN;
+        }
+
+        final boolean explain = allocation.debugDecision();
+        Decision shardLevelDecision = allocation.deciders().canAllocate(shard, allocation);
+        if (shardLevelDecision.type() == Decision.Type.NO && explain == false) {
+            // NO decision for allocating the shard, irrespective of any particular node, so exit early
+            return AllocateUnassignedDecision.no(UnassignedInfo.AllocationStatus.DECIDERS_NO, null);
+        }
+
+        /* find an node with minimal weight we can allocate on*/
+        float minWeight = Float.POSITIVE_INFINITY;
+        BalancedShardsAllocator.ModelNode minNode = null;
+        Decision decision = null;
+        /* Don't iterate over an identity hashset here the
+         * iteration order is different for each run and makes testing hard */
+        Map<String, NodeAllocationResult> nodeExplanationMap = explain ? new HashMap<>() : null;
+        List<Tuple<String, Float>> nodeWeights = explain ? new ArrayList<>() : null;
+        for (BalancedShardsAllocator.ModelNode node : nodes.values()) {
+            if (node.containsShard(shard) && explain == false) {
+                // decision is NO without needing to check anything further, so short circuit
+                continue;
+            }
+
+            // weight of this index currently on the node
+            float currentWeight = weight.weightWithAllocationConstraints(this, node, shard.getIndexName());
+            // moving the shard would not improve the balance, and we are not in explain mode, so short circuit
+            if (currentWeight > minWeight && explain == false) {
+                continue;
+            }
+
+            Decision currentDecision = allocation.deciders().canAllocate(shard, node.getRoutingNode(), allocation);
+            if (explain) {
+                nodeExplanationMap.put(node.getNodeId(), new NodeAllocationResult(node.getRoutingNode().node(), currentDecision, 0));
+                nodeWeights.add(Tuple.tuple(node.getNodeId(), currentWeight));
+            }
+            if (currentDecision.type() == Decision.Type.YES || currentDecision.type() == Decision.Type.THROTTLE) {
+                final boolean updateMinNode;
+                if (currentWeight == minWeight) {
+                    /*  we have an equal weight tie breaking:
+                     *  1. if one decision is YES prefer it
+                     *  2. prefer the node that holds the primary for this index with the next id in the ring ie.
+                     *  for the 3 shards 2 replica case we try to build up:
+                     *    1 2 0
+                     *    2 0 1
+                     *    0 1 2
+                     *  such that if we need to tie-break we try to prefer the node holding a shard with the minimal id greater
+                     *  than the id of the shard we need to assign. This works find when new indices are created since
+                     *  primaries are added first and we only add one shard set a time in this algorithm.
+                     */
+                    if (currentDecision.type() == decision.type()) {
+                        final int repId = shard.id();
+                        final int nodeHigh = node.highestPrimary(shard.index().getName());
+                        final int minNodeHigh = minNode.highestPrimary(shard.getIndexName());
+                        updateMinNode = ((((nodeHigh > repId && minNodeHigh > repId) || (nodeHigh < repId && minNodeHigh < repId))
+                            && (nodeHigh < minNodeHigh)) || (nodeHigh > repId && minNodeHigh < repId));
+                    } else {
+                        updateMinNode = currentDecision.type() == Decision.Type.YES;
+                    }
+                } else {
+                    updateMinNode = currentWeight < minWeight;
+                }
+                if (updateMinNode) {
+                    minNode = node;
+                    minWeight = currentWeight;
+                    decision = currentDecision;
+                }
+            }
+        }
+        if (decision == null) {
+            // decision was not set and a node was not assigned, so treat it as a NO decision
+            decision = Decision.NO;
+        }
+        List<NodeAllocationResult> nodeDecisions = null;
+        if (explain) {
+            nodeDecisions = new ArrayList<>();
+            // fill in the correct weight ranking, once we've been through all nodes
+            nodeWeights.sort((nodeWeight1, nodeWeight2) -> Float.compare(nodeWeight1.v2(), nodeWeight2.v2()));
+            int weightRanking = 0;
+            for (Tuple<String, Float> nodeWeight : nodeWeights) {
+                NodeAllocationResult current = nodeExplanationMap.get(nodeWeight.v1());
+                nodeDecisions.add(new NodeAllocationResult(current.getNode(), current.getCanAllocateDecision(), ++weightRanking));
+            }
+        }
+        return AllocateUnassignedDecision.fromDecision(decision, minNode != null ? minNode.getRoutingNode().node() : null, nodeDecisions);
+    }
+
+    private static final Comparator<ShardRouting> BY_DESCENDING_SHARD_ID = Comparator.comparing(ShardRouting::shardId).reversed();
+    private static final Comparator<ShardRouting> PRIMARY_FIRST = Comparator.comparing(ShardRouting::primary).reversed();
+
+    /**
+     * Tries to find a relocation from the max node to the minimal node for an arbitrary shard of the given index on the
+     * balance model. Iff this method returns a <code>true</code> the relocation has already been executed on the
+     * simulation model as well as on the cluster.
+     */
+    private boolean tryRelocateShard(BalancedShardsAllocator.ModelNode minNode, BalancedShardsAllocator.ModelNode maxNode, String idx) {
+        final BalancedShardsAllocator.ModelIndex index = maxNode.getIndex(idx);
+        if (index != null) {
+            logger.trace("Try relocating shard of [{}] from [{}] to [{}]", idx, maxNode.getNodeId(), minNode.getNodeId());
+            Stream<ShardRouting> routingStream = StreamSupport.stream(index.spliterator(), false)
+                .filter(ShardRouting::started) // cannot rebalance unassigned, initializing or relocating shards anyway
+                .filter(maxNode::containsShard) // check shards which are present on heaviest node
+                .sorted(BY_DESCENDING_SHARD_ID); // check in descending order of shard id so that the decision is deterministic
+
+            // If primary balance is preferred then prioritize moving primaries first
+            if (preferPrimaryBalance == true) {
+                routingStream = routingStream.sorted(PRIMARY_FIRST);
+            }
+            final Iterable<ShardRouting> shardRoutings = routingStream::iterator;
+            final AllocationDeciders deciders = allocation.deciders();
+            for (ShardRouting shard : shardRoutings) {
+                final Decision rebalanceDecision = deciders.canRebalance(shard, allocation);
+                if (rebalanceDecision.type() == Decision.Type.NO) {
+                    continue;
+                }
+                final Decision allocationDecision = deciders.canAllocate(shard, minNode.getRoutingNode(), allocation);
+                if (allocationDecision.type() == Decision.Type.NO) {
+                    continue;
+                }
+                // This is a safety net which prevents un-necessary primary shard relocations from maxNode to minNode when
+                // doing such relocation wouldn't help in primary balance.
+                if (preferPrimaryBalance == true
+                    && shard.primary()
+                    && maxNode.numPrimaryShards(shard.getIndexName()) - minNode.numPrimaryShards(shard.getIndexName()) < 2) {
+                    continue;
+                }
+
+                final Decision decision = new Decision.Multi().add(allocationDecision).add(rebalanceDecision);
+                maxNode.removeShard(shard);
+                long shardSize = allocation.clusterInfo().getShardSize(shard, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE);
+
+                if (decision.type() == Decision.Type.YES) {
+                    /* only allocate on the cluster if we are not throttled */
+                    logger.debug("Relocate [{}] from [{}] to [{}]", shard, maxNode.getNodeId(), minNode.getNodeId());
+                    minNode.addShard(routingNodes.relocateShard(shard, minNode.getNodeId(), shardSize, allocation.changes()).v1());
+                    return true;
+                } else {
+                    /* allocate on the model even if throttled */
+                    logger.debug("Simulate relocation of [{}] from [{}] to [{}]", shard, maxNode.getNodeId(), minNode.getNodeId());
+                    assert decision.type() == Decision.Type.THROTTLE;
+                    minNode.addShard(shard.relocate(minNode.getNodeId(), shardSize));
+                    return false;
+                }
+            }
+        }
+        logger.trace("No shards of [{}] can relocate from [{}] to [{}]", idx, maxNode.getNodeId(), minNode.getNodeId());
+        return false;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/RemoteShardsBalancer.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/RemoteShardsBalancer.java
new file mode 100644
index 0000000000000..cbbcd61fc5295
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/RemoteShardsBalancer.java
@@ -0,0 +1,655 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation.allocator;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingPool;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.routing.allocation.AllocateUnassignedDecision;
+import org.opensearch.cluster.routing.allocation.MoveDecision;
+import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+import org.opensearch.cluster.routing.allocation.decider.Decision;
+import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
+import org.opensearch.common.Randomness;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Set;
+
+/**
+ * A {@link RemoteShardsBalancer} used by the {@link BalancedShardsAllocator} to perform allocation operations
+ * for remote shards within the cluster.
+ *
+ * @opensearch.internal
+ */
+public final class RemoteShardsBalancer extends ShardsBalancer {
+    private final Logger logger;
+    private final RoutingAllocation allocation;
+    private final RoutingNodes routingNodes;
+
+    public RemoteShardsBalancer(Logger logger, RoutingAllocation allocation) {
+        this.logger = logger;
+        this.allocation = allocation;
+        this.routingNodes = allocation.routingNodes();
+    }
+
+    /**
+     * Allocates unassigned remote shards on the routing node which are filtered using
+     * {@link #groupUnassignedShardsByIndex}
+     */
+    @Override
+    void allocateUnassigned() {
+        unassignIgnoredRemoteShards(allocation);
+        if (routingNodes.unassigned().isEmpty()) {
+            logger.debug("No unassigned remote shards found.");
+            return;
+        }
+
+        Queue<RoutingNode> nodeQueue = getShuffledRemoteNodes();
+        if (nodeQueue.isEmpty()) {
+            logger.debug("No remote searcher nodes available for unassigned remote shards.");
+            failUnattemptedShards();
+            return;
+        }
+
+        Map<String, UnassignedIndexShards> unassignedShardMap = groupUnassignedShardsByIndex();
+        allocateUnassignedPrimaries(nodeQueue, unassignedShardMap);
+        allocateUnassignedReplicas(nodeQueue, unassignedShardMap);
+        ignoreRemainingShards(unassignedShardMap);
+    }
+
+    /**
+     * Performs shard movement for incompatible remote shards
+     */
+    @Override
+    void moveShards() {
+        Queue<RoutingNode> eligibleNodes = new ArrayDeque<>();
+        Queue<RoutingNode> excludedNodes = new ArrayDeque<>();
+        classifyNodesForShardMovement(eligibleNodes, excludedNodes);
+
+        if (excludedNodes.isEmpty()) {
+            logger.debug("No excluded nodes found. Returning...");
+            return;
+        }
+
+        while (!eligibleNodes.isEmpty() && !excludedNodes.isEmpty()) {
+            RoutingNode sourceNode = excludedNodes.poll();
+            for (ShardRouting ineligibleShard : sourceNode) {
+                if (ineligibleShard.started() == false) {
+                    continue;
+                }
+
+                if (!RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(ineligibleShard, allocation))) {
+                    continue;
+                }
+
+                if (eligibleNodes.isEmpty()) {
+                    break;
+                }
+
+                tryShardMovementToEligibleNode(eligibleNodes, ineligibleShard);
+            }
+        }
+    }
+
+    /**
+     * Classifies the nodes into eligible and excluded depending on whether node is able or unable for shard assignment
+     * @param eligibleNodes contains the list of classified nodes eligible to accept shards
+     * @param excludedNodes contains the list of classified nodes that are unable for assigning shards
+     */
+    private void classifyNodesForShardMovement(Queue<RoutingNode> eligibleNodes, Queue<RoutingNode> excludedNodes) {
+        List<RoutingNode> remoteRoutingNodes = getRemoteRoutingNodes();
+        int throttledNodeCount = 0;
+        for (RoutingNode node : remoteRoutingNodes) {
+            Decision nodeDecision = allocation.deciders().canAllocateAnyShardToNode(node, allocation);
+            /* canAllocateAnyShardToNode decision can be THROTTLE for throttled nodes. To classify
+             * as excluded nodes, we look for Decision.Type.NO
+             */
+            if (nodeDecision.type() == Decision.Type.NO) {
+                excludedNodes.add(node);
+            } else if (nodeDecision.type() == Decision.Type.YES) {
+                eligibleNodes.add(node);
+            } else {
+                throttledNodeCount++;
+            }
+            logger.debug(
+                "Excluded Node Count: [{}], Eligible Node Count: [{}], Throttled Node Count: [{}]",
+                excludedNodes.size(),
+                eligibleNodes.size(),
+                throttledNodeCount
+            );
+        }
+    }
+
+    /**
+     * Tries to move a shard assigned to an excluded node to an eligible node.
+     *
+     * @param eligibleNodes set of nodes that are still accepting shards
+     * @param shard the ineligible shard to be moved
+     */
+    private void tryShardMovementToEligibleNode(Queue<RoutingNode> eligibleNodes, ShardRouting shard) {
+        Set<String> nodesCheckedForShard = new HashSet<>();
+        while (!eligibleNodes.isEmpty()) {
+            RoutingNode targetNode = eligibleNodes.poll();
+            Decision currentShardDecision = allocation.deciders().canAllocate(shard, targetNode, allocation);
+
+            if (currentShardDecision.type() == Decision.Type.YES) {
+                if (logger.isDebugEnabled()) {
+                    logger.debug(
+                        "Moving shard: {} from node: [{}] to node: [{}]",
+                        shardShortSummary(shard),
+                        shard.currentNodeId(),
+                        targetNode.nodeId()
+                    );
+                }
+                routingNodes.relocateShard(
+                    shard,
+                    targetNode.nodeId(),
+                    allocation.clusterInfo().getShardSize(shard, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE),
+                    allocation.changes()
+                );
+                eligibleNodes.offer(targetNode);
+                break;
+            } else {
+                if (logger.isTraceEnabled()) {
+                    logger.trace(
+                        "Cannot move shard: {} to node: [{}]. Decisions: [{}]",
+                        shardShortSummary(shard),
+                        targetNode.nodeId(),
+                        currentShardDecision.getDecisions()
+                    );
+                }
+
+                Decision nodeLevelDecision = allocation.deciders().canAllocateAnyShardToNode(targetNode, allocation);
+                if (nodeLevelDecision.type() == Decision.Type.YES) {
+                    logger.debug("Node: [{}] can still accept shards. Adding it back to the queue.", targetNode.nodeId());
+                    eligibleNodes.offer(targetNode);
+                    nodesCheckedForShard.add(targetNode.nodeId());
+                } else {
+                    logger.debug("Node: [{}] cannot accept any more shards. Removing it from queue.", targetNode.nodeId());
+                }
+
+                // Break out if all nodes in the queue have been checked for this shard
+                if (eligibleNodes.stream().allMatch(rn -> nodesCheckedForShard.contains(rn.nodeId()))) {
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * Performs heuristic, naive weight-based balancing for remote shards within the cluster by using average nodes per
+     * cluster as the metric for shard distribution.
+     * It does so without accounting for the local shards located on any nodes within the cluster.
+     */
+    @Override
+    void balance() {
+        List<RoutingNode> remoteRoutingNodes = getRemoteRoutingNodes();
+        logger.trace("Performing balancing for remote shards.");
+
+        if (remoteRoutingNodes.isEmpty()) {
+            logger.debug("No eligible remote nodes found to perform balancing");
+            return;
+        }
+
+        final Map<String, Integer> nodePrimaryShardCount = calculateNodePrimaryShardCount(remoteRoutingNodes);
+        int totalPrimaryShardCount = nodePrimaryShardCount.values().stream().reduce(0, Integer::sum);
+
+        totalPrimaryShardCount += routingNodes.unassigned().getNumPrimaries();
+        int avgPrimaryPerNode = (totalPrimaryShardCount + routingNodes.size() - 1) / routingNodes.size();
+
+        ArrayDeque<RoutingNode> sourceNodes = new ArrayDeque<>();
+        ArrayDeque<RoutingNode> targetNodes = new ArrayDeque<>();
+        for (RoutingNode node : remoteRoutingNodes) {
+            if (nodePrimaryShardCount.get(node.nodeId()) > avgPrimaryPerNode) {
+                sourceNodes.add(node);
+            } else if (nodePrimaryShardCount.get(node.nodeId()) < avgPrimaryPerNode) {
+                targetNodes.add(node);
+            }
+        }
+
+        while (!sourceNodes.isEmpty() && !targetNodes.isEmpty()) {
+            RoutingNode sourceNode = sourceNodes.poll();
+            tryRebalanceNode(sourceNode, targetNodes, avgPrimaryPerNode, nodePrimaryShardCount);
+        }
+    }
+
+    /**
+     * Calculates the total number of primary shards per node.
+     * @param remoteRoutingNodes routing nodes for which the aggregation needs to be performed
+     * @return map of node id to primary shard count
+     */
+    private Map<String, Integer> calculateNodePrimaryShardCount(List<RoutingNode> remoteRoutingNodes) {
+        final Map<String, Integer> primaryShardCount = new HashMap<>();
+        for (RoutingNode node : remoteRoutingNodes) {
+            int totalPrimaryShardsPerNode = 0;
+            for (ShardRouting shard : node) {
+                if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation))
+                    && shard.primary()
+                    && (shard.initializing() || shard.started())) {
+                    totalPrimaryShardsPerNode++;
+                }
+            }
+            primaryShardCount.put(node.nodeId(), totalPrimaryShardsPerNode);
+        }
+        return primaryShardCount;
+    }
+
+    @Override
+    AllocateUnassignedDecision decideAllocateUnassigned(ShardRouting shardRouting) {
+        throw new UnsupportedOperationException("remote shards balancer does not support decision operations");
+    }
+
+    @Override
+    MoveDecision decideMove(ShardRouting shardRouting) {
+        throw new UnsupportedOperationException("remote shards balancer does not support decision operations");
+    }
+
+    @Override
+    MoveDecision decideRebalance(ShardRouting shardRouting) {
+        throw new UnsupportedOperationException("remote shards balancer does not support decision operations");
+    }
+
+    /**
+     * Groups unassigned shards within the allocation based on the index.
+     * @return {@link UnassignedIndexShards} grouped by index name
+     */
+    public Map<String, UnassignedIndexShards> groupUnassignedShardsByIndex() {
+        HashMap<String, UnassignedIndexShards> unassignedShardMap = new HashMap<>();
+        for (ShardRouting shard : routingNodes.unassigned().drain()) {
+            String index = shard.getIndexName();
+            if (!RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation))) {
+                routingNodes.unassigned().add(shard);
+                continue;
+            }
+            if (!unassignedShardMap.containsKey(index)) {
+                unassignedShardMap.put(index, new UnassignedIndexShards());
+            }
+            unassignedShardMap.get(index).addShard(shard);
+        }
+        return unassignedShardMap;
+    }
+
+    /**
+     * Unassigned shards from {@link LocalShardsBalancer} are ignored since the balancer cannot allocate remote shards.
+     * Prior to allocation operations done by {@link RemoteShardsBalancer}, the ignored remote shards are moved back to
+     * unassigned status.
+     */
+    private void unassignIgnoredRemoteShards(RoutingAllocation routingAllocation) {
+        RoutingNodes.UnassignedShards unassignedShards = routingAllocation.routingNodes().unassigned();
+        for (ShardRouting shard : unassignedShards.drainIgnored()) {
+            RoutingPool pool = RoutingPool.getShardPool(shard, routingAllocation);
+            if (pool == RoutingPool.REMOTE_CAPABLE && shard.unassigned() && (shard.primary() || !shard.unassignedInfo().isDelayed())) {
+                ShardRouting unassignedShard = shard;
+                // Shard when moved to an unassigned state updates the recovery source to be ExistingStoreRecoverySource
+                // Remote shards do not have an existing store to recover from and can be recovered from an empty source
+                // to re-fetch any shard blocks from the repository.
+                if (shard.primary()) {
+                    if (!RecoverySource.Type.SNAPSHOT.equals(shard.recoverySource().getType())) {
+                        unassignedShard = shard.updateUnassigned(shard.unassignedInfo(), RecoverySource.EmptyStoreRecoverySource.INSTANCE);
+                    }
+                }
+
+                unassignedShards.add(unassignedShard);
+            } else {
+                unassignedShards.ignoreShard(shard, shard.unassignedInfo().getLastAllocationStatus(), routingAllocation.changes());
+            }
+        }
+    }
+
+    private void allocateUnassignedPrimaries(Queue<RoutingNode> nodeQueue, Map<String, UnassignedIndexShards> unassignedShardMap) {
+        allocateUnassignedShards(true, nodeQueue, unassignedShardMap);
+    }
+
+    private void allocateUnassignedReplicas(Queue<RoutingNode> nodeQueue, Map<String, UnassignedIndexShards> unassignedShardMap) {
+        allocateUnassignedShards(false, nodeQueue, unassignedShardMap);
+    }
+
+    private void ignoreRemainingShards(Map<String, UnassignedIndexShards> unassignedShardMap) {
+        for (UnassignedIndexShards indexShards : unassignedShardMap.values()) {
+            for (ShardRouting shard : indexShards.getPrimaries()) {
+                routingNodes.unassigned().ignoreShard(shard, UnassignedInfo.AllocationStatus.DECIDERS_NO, allocation.changes());
+            }
+            for (ShardRouting shard : indexShards.getReplicas()) {
+                routingNodes.unassigned().ignoreShard(shard, UnassignedInfo.AllocationStatus.DECIDERS_NO, allocation.changes());
+            }
+        }
+    }
+
+    private void allocateUnassignedShards(
+        boolean primaries,
+        Queue<RoutingNode> nodeQueue,
+        Map<String, UnassignedIndexShards> unassignedShardMap
+    ) {
+        logger.debug("Allocating unassigned {}. Nodes available in queue: [{}]", (primaries ? "primaries" : "replicas"), nodeQueue.size());
+
+        // Iterate through all shards index by index and allocate them
+        for (String index : unassignedShardMap.keySet()) {
+            if (nodeQueue.isEmpty()) {
+                break;
+            }
+
+            UnassignedIndexShards indexShards = unassignedShardMap.get(index);
+            Queue<ShardRouting> shardsToAllocate = primaries ? indexShards.getPrimaries() : indexShards.getReplicas();
+            if (shardsToAllocate.isEmpty()) {
+                continue;
+            }
+            logger.debug("Allocating shards for index: [{}]", index);
+
+            while (!shardsToAllocate.isEmpty() && !nodeQueue.isEmpty()) {
+                ShardRouting shard = shardsToAllocate.poll();
+                if (shard.assignedToNode()) {
+                    if (logger.isDebugEnabled()) {
+                        logger.debug("Shard: {} already assigned to node: [{}]", shardShortSummary(shard), shard.currentNodeId());
+                    }
+                    continue;
+                }
+
+                Decision shardLevelDecision = allocation.deciders().canAllocate(shard, allocation);
+                if (shardLevelDecision.type() == Decision.Type.NO) {
+                    if (logger.isDebugEnabled()) {
+                        logger.debug(
+                            "Ignoring shard: [{}] as is cannot be allocated to any node. Shard level decisions: [{}][{}].",
+                            shardShortSummary(shard),
+                            shardLevelDecision.getDecisions(),
+                            shardLevelDecision.getExplanation()
+                        );
+                    }
+                    routingNodes.unassigned().ignoreShard(shard, UnassignedInfo.AllocationStatus.DECIDERS_NO, allocation.changes());
+                    continue;
+                }
+
+                tryAllocateUnassignedShard(nodeQueue, shard);
+            }
+        }
+    }
+
+    /**
+     * Tries to allocate an unassigned shard to one of the nodes within the node queue.
+     * @param nodeQueue ordered list of nodes to try allocation
+     * @param shard the unassigned shard which needs to be allocated
+     */
+    private void tryAllocateUnassignedShard(Queue<RoutingNode> nodeQueue, ShardRouting shard) {
+        boolean allocated = false;
+        boolean throttled = false;
+        Set<String> nodesCheckedForShard = new HashSet<>();
+        while (!nodeQueue.isEmpty()) {
+            RoutingNode node = nodeQueue.poll();
+            Decision allocateDecision = allocation.deciders().canAllocate(shard, node, allocation);
+            nodesCheckedForShard.add(node.nodeId());
+            if (allocateDecision.type() == Decision.Type.YES) {
+                if (logger.isTraceEnabled()) {
+                    logger.trace("Assigned shard [{}] to [{}]", shardShortSummary(shard), node.nodeId());
+                }
+                final long shardSize = DiskThresholdDecider.getExpectedShardSize(
+                    shard,
+                    ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE,
+                    allocation.clusterInfo(),
+                    allocation.snapshotShardSizeInfo(),
+                    allocation.metadata(),
+                    allocation.routingTable()
+                );
+                ShardRouting initShard = routingNodes.initializeShard(shard, node.nodeId(), null, shardSize, allocation.changes());
+                nodeQueue.offer(node);
+                allocated = true;
+                break;
+            } else {
+                if (logger.isTraceEnabled()) {
+                    logger.trace(
+                        "Cannot allocate shard: {} on node [{}]. Decisions: [{}]",
+                        shardShortSummary(shard),
+                        node.nodeId(),
+                        allocateDecision.getDecisions()
+                    );
+                }
+                throttled = throttled || allocateDecision.type() == Decision.Type.THROTTLE;
+
+                Decision nodeLevelDecision = allocation.deciders().canAllocateAnyShardToNode(node, allocation);
+                if (nodeLevelDecision.type() == Decision.Type.YES) {
+                    if (logger.isTraceEnabled()) {
+                        logger.trace(
+                            "Node: [{}] can still accept shards, retaining it in queue - [{}]",
+                            node.nodeId(),
+                            nodeLevelDecision.getDecisions()
+                        );
+                    }
+                    nodeQueue.offer(node);
+                } else {
+                    if (logger.isTraceEnabled()) {
+                        logger.trace(
+                            "Cannot allocate any shard to node: [{}]. Removing from queue. Node level decisions: [{}],[{}]",
+                            node.nodeId(),
+                            nodeLevelDecision.getDecisions(),
+                            nodeLevelDecision.getExplanation()
+                        );
+                    }
+                }
+
+                // Break out if all nodes in the queue have been checked for this shard
+                if (nodeQueue.stream().allMatch(rn -> nodesCheckedForShard.contains(rn.nodeId()))) {
+                    throttled = true;
+                    break;
+                }
+            }
+        }
+
+        if (!allocated) {
+            UnassignedInfo.AllocationStatus status = throttled
+                ? UnassignedInfo.AllocationStatus.DECIDERS_THROTTLED
+                : UnassignedInfo.AllocationStatus.DECIDERS_NO;
+            routingNodes.unassigned().ignoreShard(shard, status, allocation.changes());
+        }
+    }
+
+    private void tryRebalanceNode(
+        RoutingNode sourceNode,
+        ArrayDeque<RoutingNode> targetNodes,
+        int avgPrimary,
+        final Map<String, Integer> primaryCount
+    ) {
+        long shardsToBalance = primaryCount.get(sourceNode.nodeId()) - avgPrimary;
+        assert shardsToBalance >= 0 : "Shards to balance should be greater than 0, but found negative";
+        Iterator<ShardRouting> shardIterator = sourceNode.copyShards().iterator();
+        Set<String> nodesCheckedForRelocation = new HashSet<>();
+
+        // Try to relocate the valid shards on the sourceNode, one at a time;
+        // until either sourceNode is balanced OR no more active primary shard available OR all the target nodes are exhausted
+        while (shardsToBalance > 0 && shardIterator.hasNext() && !targetNodes.isEmpty()) {
+            // Find an active primary shard to relocate
+            ShardRouting shard = shardIterator.next();
+            if (!shard.started() || !shard.primary() || !RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation))) {
+                continue;
+            }
+
+            while (!targetNodes.isEmpty()) {
+                // Find a valid target node that can accommodate the current shard relocation
+                RoutingNode targetNode = targetNodes.poll();
+                if (primaryCount.get(targetNode.nodeId()) >= avgPrimary) {
+                    logger.trace("Avg shard limit reached for node: [{}]. Removing from queue.", targetNode.nodeId());
+                    continue;
+                }
+
+                // Try relocate the shard on the target node
+                Decision rebalanceDecision = tryRelocateShard(shard, targetNode);
+
+                if (rebalanceDecision.type() == Decision.Type.YES) {
+                    shardsToBalance--;
+                    primaryCount.merge(targetNode.nodeId(), 1, Integer::sum);
+                    targetNodes.offer(targetNode);
+                    break;
+
+                    // If the relocation attempt failed for the shard, check if the target node can accommodate any other shard; else remove
+                    // the target node from the target list
+                } else {
+                    Decision nodeDecision = allocation.deciders().canAllocateAnyShardToNode(targetNode, allocation);
+                    if (nodeDecision.type() == Decision.Type.YES) {
+                        targetNodes.offer(targetNode);
+                        nodesCheckedForRelocation.add(targetNode.nodeId());
+                    } else {
+                        if (logger.isTraceEnabled()) {
+                            logger.trace(
+                                "Cannot allocate any shard to node: [{}]. Removing from queue. Node level decisions: [{}],[{}]",
+                                targetNode.nodeId(),
+                                nodeDecision.getDecisions(),
+                                nodeDecision.toString()
+                            );
+                        }
+                    }
+                }
+
+                // If all the target nodes are exhausted for the current shard; skip to next shard
+                if (targetNodes.stream().allMatch(node -> nodesCheckedForRelocation.contains(node.nodeId()))) {
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * For every primary shard for which this method is invoked,
+     * swap is attempted with the destination node in case replica shard is present.
+     * In case replica is not present, relocation of the shard id performed.
+     */
+    private Decision tryRelocateShard(ShardRouting shard, RoutingNode destinationNode) {
+        // Check if there is already a replica for the shard on the destination node.
+        // Then we can directly swap the replica with the primary shards.
+        // Invariant: We only allow swap relocation on remote shards.
+        ShardRouting replicaShard = destinationNode.getByShardId(shard.shardId());
+        if (replicaShard != null) {
+            assert !replicaShard.primary() : "Primary Shard found while expected Replica during shard rebalance";
+            return executeSwapShard(shard, replicaShard, allocation);
+        }
+
+        // Since no replica present on the destinationNode; try relocating the shard to the destination node
+        Decision allocationDecision = allocation.deciders().canAllocate(shard, destinationNode, allocation);
+        Decision rebalanceDecision = allocation.deciders().canRebalance(shard, allocation);
+        logger.trace(
+            "Relocating shard [{}] from node [{}] to node [{}]. AllocationDecision: [{}]. AllocationExplanation: [{}]. "
+                + "RebalanceDecision: [{}]. RebalanceExplanation: [{}]",
+            shard.id(),
+            shard.currentNodeId(),
+            destinationNode.nodeId(),
+            allocationDecision.type(),
+            allocationDecision.toString(),
+            rebalanceDecision.type(),
+            rebalanceDecision.toString()
+        );
+
+        // Perform the relocation of allocation and rebalance decisions are YES
+        if ((allocationDecision.type() == Decision.Type.YES) && (rebalanceDecision.type() == Decision.Type.YES)) {
+            final long shardSize = allocation.clusterInfo().getShardSize(shard, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE);
+            ShardRouting targetShard = routingNodes.relocateShard(shard, destinationNode.nodeId(), shardSize, allocation.changes()).v2();
+            logger.info("Relocated shard [{}] to node [{}] during primary Rebalance", shard, targetShard.currentNodeId());
+            return Decision.YES;
+        }
+
+        if ((allocationDecision.type() == Decision.Type.THROTTLE) || (rebalanceDecision.type() == Decision.Type.THROTTLE)) {
+            return Decision.THROTTLE;
+        }
+
+        return Decision.NO;
+    }
+
+    private Decision executeSwapShard(ShardRouting primaryShard, ShardRouting replicaShard, RoutingAllocation allocation) {
+        if (!replicaShard.started()) {
+            return new Decision.Single(Decision.Type.NO);
+        }
+
+        allocation.routingNodes().swapPrimaryWithReplica(logger, primaryShard, replicaShard, allocation.changes());
+        return new Decision.Single(Decision.Type.YES);
+    }
+
+    private void failUnattemptedShards() {
+        RoutingNodes.UnassignedShards.UnassignedIterator unassignedIterator = routingNodes.unassigned().iterator();
+        while (unassignedIterator.hasNext()) {
+            ShardRouting shard = unassignedIterator.next();
+            UnassignedInfo unassignedInfo = shard.unassignedInfo();
+            if (shard.primary() && unassignedInfo.getLastAllocationStatus() == UnassignedInfo.AllocationStatus.NO_ATTEMPT) {
+                unassignedIterator.updateUnassigned(
+                    new UnassignedInfo(
+                        unassignedInfo.getReason(),
+                        unassignedInfo.getMessage(),
+                        unassignedInfo.getFailure(),
+                        unassignedInfo.getNumFailedAllocations(),
+                        unassignedInfo.getUnassignedTimeInNanos(),
+                        unassignedInfo.getUnassignedTimeInMillis(),
+                        unassignedInfo.isDelayed(),
+                        UnassignedInfo.AllocationStatus.DECIDERS_NO,
+                        Collections.emptySet()
+                    ),
+                    shard.recoverySource(),
+                    allocation.changes()
+                );
+            }
+        }
+    }
+
+    private Queue<RoutingNode> getShuffledRemoteNodes() {
+        List<RoutingNode> nodeList = getRemoteRoutingNodes();
+        Randomness.shuffle(nodeList);
+        return new ArrayDeque<>(nodeList);
+    }
+
+    /**
+     * Filters out and returns the list of {@link RoutingPool#REMOTE_CAPABLE} nodes from the routing nodes in cluster.
+     * @return list of {@link RoutingPool#REMOTE_CAPABLE} routing nodes.
+     */
+    private List<RoutingNode> getRemoteRoutingNodes() {
+        List<RoutingNode> nodeList = new ArrayList<>();
+        for (RoutingNode rNode : routingNodes) {
+            if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getNodePool(rNode))) {
+                nodeList.add(rNode);
+            }
+        }
+        return nodeList;
+    }
+
+    /**
+     * {@link UnassignedIndexShards} maintains a queue of unassigned remote shards for allocation operations within
+     * the cluster.
+     *
+     * @opensearch.internal
+     */
+    public static class UnassignedIndexShards {
+        private final Queue<ShardRouting> primaries = new ArrayDeque<>();
+        private final Queue<ShardRouting> replicas = new ArrayDeque<>();
+
+        public void addShard(ShardRouting shard) {
+            if (shard.primary()) {
+                primaries.add(shard);
+            } else {
+                replicas.add(shard);
+            }
+        }
+
+        public Queue<ShardRouting> getPrimaries() {
+            return primaries;
+        }
+
+        public Queue<ShardRouting> getReplicas() {
+            return replicas;
+        }
+    }
+
+    private String shardShortSummary(ShardRouting shard) {
+        return "[" + shard.getIndexName() + "]" + "[" + shard.getId() + "]" + "[" + (shard.primary() ? "p" : "r") + "]";
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsAllocator.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsAllocator.java
index 8c63f0ff3ffaa..63d8c656f5049 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsAllocator.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsAllocator.java
@@ -44,6 +44,8 @@
  * The allocator makes basic decision where a shard instance will be allocated, if already allocated instances
  * need to relocate to other nodes due to node failures or due to rebalancing decisions.
  * </p>
+ *
+ * @opensearch.internal
  */
 public interface ShardsAllocator {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsBalancer.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsBalancer.java
new file mode 100644
index 0000000000000..ef2dbd34644a7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/ShardsBalancer.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation.allocator;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.AllocateUnassignedDecision;
+import org.opensearch.cluster.routing.allocation.MoveDecision;
+
+/**
+ * <p>
+ * A {@link ShardsBalancer} helps the {@link BalancedShardsAllocator} to perform allocation and balancing
+ * operations on the cluster.
+ * </p>
+ *
+ * @opensearch.internal
+ */
+public abstract class ShardsBalancer {
+
+    /**
+     * Performs allocation of unassigned shards on nodes within the cluster.
+     */
+    abstract void allocateUnassigned();
+
+    /**
+     * Moves shards that cannot be allocated to a node anymore.
+     */
+    abstract void moveShards();
+
+    /**
+     *  Balances the nodes on the cluster model.
+     */
+    abstract void balance();
+
+    /**
+     * Make a decision for allocating an unassigned shard.
+     * @param shardRouting the shard for which the decision has to be made
+     * @return the allocation decision
+     */
+    abstract AllocateUnassignedDecision decideAllocateUnassigned(ShardRouting shardRouting);
+
+    /**
+     * Makes a decision on whether to move a started shard to another node.
+     * @param shardRouting the shard for which the decision has to be made
+     * @return a move decision for the shard
+     */
+    abstract MoveDecision decideMove(ShardRouting shardRouting);
+
+    /**
+     * Makes a decision about moving a single shard to a different node to form a more
+     * optimally balanced cluster.
+     * @param shardRouting the shard for which the move decision has to be made
+     * @return a move decision for the shard
+     */
+    abstract MoveDecision decideRebalance(ShardRouting shardRouting);
+
+    /**
+     * Returns the average of shards per node for the given index
+     */
+    public float avgShardsPerNode() {
+        return Float.MAX_VALUE;
+    }
+
+    /**
+     * Returns the global average of shards per node
+     */
+    public float avgShardsPerNode(String index) {
+        return Float.MAX_VALUE;
+    }
+
+    /**
+     * Returns the average of primary shards per node for the given index
+     */
+    public float avgPrimaryShardsPerNode(String index) {
+        return Float.MAX_VALUE;
+    }
+
+    /**
+     * Returns the average of primary shards per node
+     */
+    public float avgPrimaryShardsPerNode() {
+        return Float.MAX_VALUE;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/package-info.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/package-info.java
new file mode 100644
index 0000000000000..0481bbff1439c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Foundation classes to ensure balanced shards. */
+package org.opensearch.cluster.routing.allocation.allocator;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AbstractAllocateAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AbstractAllocateAllocationCommand.java
index 889999b13291f..e8e6b48d0901e 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AbstractAllocateAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AbstractAllocateAllocationCommand.java
@@ -42,19 +42,21 @@
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Abstract base class for allocating an unassigned shard to a node
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractAllocateAllocationCommand implements AllocationCommand {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateEmptyPrimaryAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateEmptyPrimaryAllocationCommand.java
index e0eeb2dd179c3..9ea9ca617ac9d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateEmptyPrimaryAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateEmptyPrimaryAllocationCommand.java
@@ -42,12 +42,12 @@
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 
 import java.io.IOException;
@@ -57,6 +57,8 @@
 /**
  * Allocates an unassigned empty primary shard to a specific node. Use with extreme care as this will result in data loss.
  * Allocation deciders are ignored.
+ *
+ * @opensearch.internal
  */
 public class AllocateEmptyPrimaryAllocationCommand extends BasePrimaryAllocationCommand {
     public static final String NAME = "allocate_empty_primary";
@@ -96,6 +98,11 @@ public static AllocateEmptyPrimaryAllocationCommand fromXContent(XContentParser
         return new Builder().parse(parser).build();
     }
 
+    /**
+     * Builder for an empty primary allocation.
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends BasePrimaryAllocationCommand.Builder<AllocateEmptyPrimaryAllocationCommand> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateReplicaAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateReplicaAllocationCommand.java
index d72b89478af0d..d545c9090e81f 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateReplicaAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateReplicaAllocationCommand.java
@@ -39,10 +39,10 @@
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.shard.ShardNotFoundException;
 
@@ -52,6 +52,8 @@
 
 /**
  * Allocates an unassigned replica shard to a specific node. Checks if allocation deciders allow allocation.
+ *
+ * @opensearch.internal
  */
 public class AllocateReplicaAllocationCommand extends AbstractAllocateAllocationCommand {
     public static final String NAME = "allocate_replica";
@@ -86,6 +88,11 @@ public static AllocateReplicaAllocationCommand fromXContent(XContentParser parse
         return new Builder().parse(parser).build();
     }
 
+    /**
+     * A builder for the command.
+     *
+     * @opensearch.internal
+     */
     protected static class Builder extends AbstractAllocateAllocationCommand.Builder<AllocateReplicaAllocationCommand> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateStalePrimaryAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateStalePrimaryAllocationCommand.java
index b5f8bfaa3c48b..983265ed5f960 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateStalePrimaryAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocateStalePrimaryAllocationCommand.java
@@ -40,10 +40,10 @@
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.shard.ShardNotFoundException;
 
@@ -53,6 +53,8 @@
 /**
  * Allocates an unassigned stale primary shard to a specific node. Use with extreme care as this will result in data loss.
  * Allocation deciders are ignored.
+ *
+ * @opensearch.internal
  */
 public class AllocateStalePrimaryAllocationCommand extends BasePrimaryAllocationCommand {
     public static final String NAME = "allocate_stale_primary";
@@ -93,6 +95,11 @@ public static AllocateStalePrimaryAllocationCommand fromXContent(XContentParser
         return new Builder().parse(parser).build();
     }
 
+    /**
+     * Builder for a stale primary allocation
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends BasePrimaryAllocationCommand.Builder<AllocateStalePrimaryAllocationCommand> {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommand.java
index 5bd5dec7e350e..7fffb0299af85 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommand.java
@@ -35,9 +35,9 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.common.io.stream.NamedWriteable;
 import org.opensearch.common.network.NetworkModule;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 import java.util.Optional;
 
@@ -45,6 +45,8 @@
  * A command to move shards in some way.
  *
  * Commands are registered in {@link NetworkModule}.
+ *
+ * @opensearch.internal
  */
 public interface AllocationCommand extends NamedWriteable, ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommands.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommands.java
index deb316491993d..ac804819443a5 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommands.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/AllocationCommands.java
@@ -36,12 +36,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.RoutingExplanations;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -52,6 +53,8 @@
 /**
  * A simple {@link AllocationCommand} composite managing several
  * {@link AllocationCommand} implementations
+ *
+ * @opensearch.internal
  */
 public class AllocationCommands implements ToXContentFragment {
     private final List<AllocationCommand> commands = new ArrayList<>();
@@ -214,6 +217,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/BasePrimaryAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/BasePrimaryAllocationCommand.java
index 1d4b303124a49..17c538c60fa90 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/BasePrimaryAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/BasePrimaryAllocationCommand.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.cluster.routing.allocation.command;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * Abstract base class for allocating an unassigned primary shard to a node
+ *
+ * @opensearch.internal
  */
 public abstract class BasePrimaryAllocationCommand extends AbstractAllocateAllocationCommand {
 
@@ -83,6 +85,11 @@ public boolean acceptDataLoss() {
         return acceptDataLoss;
     }
 
+    /**
+     * Base builder class for the primary allocation command.
+     *
+     * @opensearch.internal
+     */
     protected abstract static class Builder<T extends BasePrimaryAllocationCommand> extends AbstractAllocateAllocationCommand.Builder<T> {
         protected boolean acceptDataLoss;
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/CancelAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/CancelAllocationCommand.java
index 7d4c51aeaa851..a07f3eb9d95e1 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/CancelAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/CancelAllocationCommand.java
@@ -43,13 +43,13 @@
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -57,6 +57,8 @@
 
 /**
  * A command that cancels relocation, or recovery of a given shard on a node.
+ *
+ * @opensearch.internal
  */
 public class CancelAllocationCommand implements AllocationCommand {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/MoveAllocationCommand.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/MoveAllocationCommand.java
index 4e567c0fbb4eb..e3e152dd88889 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/MoveAllocationCommand.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/MoveAllocationCommand.java
@@ -40,11 +40,11 @@
 import org.opensearch.cluster.routing.allocation.RerouteExplanation;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -53,6 +53,8 @@
  * A command that moves a shard from a specific node to another node.<br>
  * <b>Note:</b> The shard needs to be in the state
  * {@link ShardRoutingState#STARTED} in order to be moved.
+ *
+ * @opensearch.internal
  */
 public class MoveAllocationCommand implements AllocationCommand {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/command/package-info.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/package-info.java
new file mode 100644
index 0000000000000..8489c49c78752
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/command/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Allocation Command transport handlers. */
+package org.opensearch.cluster.routing.allocation.command;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecider.java
index 498b3d8ad601e..24c3fd7f34e4a 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecider.java
@@ -43,6 +43,8 @@
  * {@link AllocationDecider} is an abstract base class that allows to make
  * dynamic cluster- or index-wide shard allocation decisions on a per-node
  * basis.
+ *
+ * @opensearch.internal
  */
 public abstract class AllocationDecider {
     /**
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDeciders.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDeciders.java
index 388b7ac27bf60..dca82f75d6fb5 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDeciders.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AllocationDeciders.java
@@ -46,6 +46,8 @@
 /**
  * A composite {@link AllocationDecider} combining the "decision" of multiple
  * {@link AllocationDecider} implementations into a single allocation decision.
+ *
+ * @opensearch.internal
  */
 public class AllocationDeciders extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AwarenessAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AwarenessAllocationDecider.java
index bf78745e07a6b..5344d95b217a7 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AwarenessAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/AwarenessAllocationDecider.java
@@ -32,21 +32,22 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.function.Function;
-
-import com.carrotsearch.hppc.ObjectIntHashMap;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
 
 import static java.util.Collections.emptyList;
 
@@ -89,6 +90,8 @@
  * <pre>
  * node.zone: zone1
  * </pre>
+ *
+ * @opensearch.internal
  */
 public class AwarenessAllocationDecider extends AllocationDecider {
 
@@ -173,16 +176,16 @@ private Decision underCapacity(ShardRouting shardRouting, RoutingNode node, Rout
             }
 
             // build attr_value -> nodes map
-            ObjectIntHashMap<String> nodesPerAttribute = allocation.routingNodes().nodesPerAttributesCounts(awarenessAttribute);
+            Set<String> nodesPerAttribute = allocation.routingNodes().nodesPerAttributesCounts(awarenessAttribute);
 
             // build the count of shards per attribute value
-            ObjectIntHashMap<String> shardPerAttribute = new ObjectIntHashMap<>();
+            Map<String, Integer> shardPerAttribute = new HashMap<>();
             for (ShardRouting assignedShard : allocation.routingNodes().assignedShards(shardRouting.shardId())) {
                 if (assignedShard.started() || assignedShard.initializing()) {
                     // Note: this also counts relocation targets as that will be the new location of the shard.
                     // Relocation sources should not be counted as the shard is moving away
                     RoutingNode routingNode = allocation.routingNodes().node(assignedShard.currentNodeId());
-                    shardPerAttribute.addTo(routingNode.node().getAttributes().get(awarenessAttribute), 1);
+                    shardPerAttribute.merge(routingNode.node().getAttributes().get(awarenessAttribute), 1, Integer::sum);
                 }
             }
 
@@ -191,26 +194,27 @@ private Decision underCapacity(ShardRouting shardRouting, RoutingNode node, Rout
                     String nodeId = shardRouting.relocating() ? shardRouting.relocatingNodeId() : shardRouting.currentNodeId();
                     if (node.nodeId().equals(nodeId) == false) {
                         // we work on different nodes, move counts around
-                        shardPerAttribute.putOrAdd(
+                        shardPerAttribute.compute(
                             allocation.routingNodes().node(nodeId).node().getAttributes().get(awarenessAttribute),
-                            0,
-                            -1
+                            (k, v) -> (v == null) ? 0 : v - 1
                         );
-                        shardPerAttribute.addTo(node.node().getAttributes().get(awarenessAttribute), 1);
+                        shardPerAttribute.merge(node.node().getAttributes().get(awarenessAttribute), 1, Integer::sum);
                     }
                 } else {
-                    shardPerAttribute.addTo(node.node().getAttributes().get(awarenessAttribute), 1);
+                    shardPerAttribute.merge(node.node().getAttributes().get(awarenessAttribute), 1, Integer::sum);
                 }
             }
 
             int numberOfAttributes = nodesPerAttribute.size();
             List<String> fullValues = forcedAwarenessAttributes.get(awarenessAttribute);
+
             if (fullValues != null) {
-                for (String fullValue : fullValues) {
-                    if (shardPerAttribute.containsKey(fullValue) == false) {
-                        numberOfAttributes++;
-                    }
+                // If forced awareness is enabled, numberOfAttributes = count(distinct((union(discovered_attributes, forced_attributes)))
+                Set<String> attributesSet = new HashSet<>(fullValues);
+                for (String stringObjectCursor : nodesPerAttribute) {
+                    attributesSet.add(stringObjectCursor);
                 }
+                numberOfAttributes = attributesSet.size();
             }
             // TODO should we remove ones that are not part of full list?
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ClusterRebalanceAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ClusterRebalanceAllocationDecider.java
index c3253ac3241c7..857192d4f3041 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ClusterRebalanceAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ClusterRebalanceAllocationDecider.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import java.util.Locale;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.routing.ShardRouting;
@@ -43,6 +41,8 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 
+import java.util.Locale;
+
 /**
  * This {@link AllocationDecider} controls re-balancing operations based on the
  * cluster wide active shard state. This decided can not be configured in
@@ -59,6 +59,8 @@
  * <li>{@code always} - Re-balancing is allowed once a shard replication group
  * is active</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public class ClusterRebalanceAllocationDecider extends AllocationDecider {
 
@@ -76,6 +78,8 @@ public class ClusterRebalanceAllocationDecider extends AllocationDecider {
 
     /**
      * An enum representation for the configured re-balance type.
+     *
+     * @opensearch.internal
      */
     public enum ClusterRebalanceType {
         /**
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRebalanceAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRebalanceAllocationDecider.java
index a9e801035cc30..43a351f520922 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRebalanceAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRebalanceAllocationDecider.java
@@ -52,6 +52,8 @@
  * {@code cluster.routing.allocation.cluster_concurrent_rebalance}. Iff this
  * setting is set to {@code -1} the number of concurrent re-balance operations
  * are unlimited.
+ *
+ * @opensearch.internal
  */
 public class ConcurrentRebalanceAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRecoveriesAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRecoveriesAllocationDecider.java
index 8abed3f9aed2d..62276c470a86b 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRecoveriesAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ConcurrentRecoveriesAllocationDecider.java
@@ -13,6 +13,8 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
@@ -20,8 +22,6 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 
 /**
  * This {@link AllocationDecider} controls the number of currently in-progress
@@ -32,6 +32,8 @@
  * <code>cluster.routing.allocation.cluster_concurrent_recoveries</code>. Iff this
  * setting is set to <code>-1</code> the number of cluster concurrent recoveries operations
  * are unlimited.
+ *
+ * @opensearch.internal
  */
 public class ConcurrentRecoveriesAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/Decision.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/Decision.java
index 6af4f01ffb891..807ab070b82b1 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/Decision.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/Decision.java
@@ -33,13 +33,13 @@
 package org.opensearch.cluster.routing.allocation.decider;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -53,6 +53,8 @@
  * allocation process.
  *
  * @see AllocationDecider
+ *
+ * @opensearch.internal
  */
 public abstract class Decision implements ToXContent, Writeable {
 
@@ -95,6 +97,8 @@ public static Decision readFrom(StreamInput in) throws IOException {
     /**
      * This enumeration defines the
      * possible types of decisions
+     *
+     * @opensearch.internal
      */
     public enum Type implements Writeable {
         YES(1),
@@ -168,6 +172,8 @@ public boolean canPremptivelyReturn() {
 
     /**
      * Simple class representing a single decision
+     *
+     * @opensearch.internal
      */
     public static class Single extends Decision implements ToXContentObject {
         private Type type;
@@ -285,6 +291,8 @@ public void writeTo(StreamOutput out) throws IOException {
 
     /**
      * Simple class representing a list of decisions
+     *
+     * @opensearch.internal
      */
     public static class Multi extends Decision implements ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDecider.java
index aa8c0c95ea597..1bd47f111591d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDecider.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
@@ -48,21 +47,28 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
 
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 
+import static org.opensearch.cluster.routing.RoutingPool.REMOTE_CAPABLE;
+import static org.opensearch.cluster.routing.RoutingPool.getNodePool;
+import static org.opensearch.cluster.routing.RoutingPool.getShardPool;
 import static org.opensearch.cluster.routing.allocation.DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING;
 import static org.opensearch.cluster.routing.allocation.DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_LOW_DISK_WATERMARK_SETTING;
+import static org.opensearch.index.store.remote.filecache.FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING;
 
 /**
  * The {@link DiskThresholdDecider} checks that the node a shard is potentially
@@ -86,6 +92,8 @@
  *
  * <code>cluster.routing.allocation.disk.threshold_enabled</code> is used to
  * enable or disable this decider. It defaults to true (enabled).
+ *
+ * @opensearch.internal
  */
 public class DiskThresholdDecider extends AllocationDecider {
 
@@ -166,7 +174,43 @@ public static long sizeOfRelocatingShards(
     @Override
     public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
         ClusterInfo clusterInfo = allocation.clusterInfo();
-        ImmutableOpenMap<String, DiskUsage> usages = clusterInfo.getNodeMostAvailableDiskUsages();
+
+        /*
+         The following block enables allocation for remote shards within safeguard limits of the filecache.
+         */
+        if (REMOTE_CAPABLE.equals(getNodePool(node)) && REMOTE_CAPABLE.equals(getShardPool(shardRouting, allocation))) {
+            final List<ShardRouting> remoteShardsOnNode = StreamSupport.stream(node.spliterator(), false)
+                .filter(shard -> shard.primary() && REMOTE_CAPABLE.equals(getShardPool(shard, allocation)))
+                .collect(Collectors.toList());
+            final long currentNodeRemoteShardSize = remoteShardsOnNode.stream()
+                .map(ShardRouting::getExpectedShardSize)
+                .mapToLong(Long::longValue)
+                .sum();
+
+            final long shardSize = getExpectedShardSize(
+                shardRouting,
+                0L,
+                allocation.clusterInfo(),
+                allocation.snapshotShardSizeInfo(),
+                allocation.metadata(),
+                allocation.routingTable()
+            );
+
+            final FileCacheStats fileCacheStats = clusterInfo.getNodeFileCacheStats().getOrDefault(node.nodeId(), null);
+            final long nodeCacheSize = fileCacheStats != null ? fileCacheStats.getTotal().getBytes() : 0;
+            final long totalNodeRemoteShardSize = currentNodeRemoteShardSize + shardSize;
+            final double dataToFileCacheSizeRatio = DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING.get(allocation.metadata().settings());
+            if (dataToFileCacheSizeRatio > 0.0f && totalNodeRemoteShardSize > dataToFileCacheSizeRatio * nodeCacheSize) {
+                return allocation.decision(
+                    Decision.NO,
+                    NAME,
+                    "file cache limit reached - remote shard size will exceed configured safeguard ratio"
+                );
+            }
+            return Decision.YES;
+        }
+
+        Map<String, DiskUsage> usages = clusterInfo.getNodeMostAvailableDiskUsages();
         final Decision decision = earlyTerminate(allocation, usages);
         if (decision != null) {
             return decision;
@@ -421,8 +465,17 @@ public Decision canRemain(ShardRouting shardRouting, RoutingNode node, RoutingAl
         if (shardRouting.currentNodeId().equals(node.nodeId()) == false) {
             throw new IllegalArgumentException("Shard [" + shardRouting + "] is not allocated on node: [" + node.nodeId() + "]");
         }
+
+        /*
+         The following block prevents movement for remote shards since they do not use the local storage as
+         the primary source of data storage.
+         */
+        if (REMOTE_CAPABLE.equals(getNodePool(node)) && REMOTE_CAPABLE.equals(getShardPool(shardRouting, allocation))) {
+            return Decision.ALWAYS;
+        }
+
         final ClusterInfo clusterInfo = allocation.clusterInfo();
-        final ImmutableOpenMap<String, DiskUsage> usages = clusterInfo.getNodeLeastAvailableDiskUsages();
+        final Map<String, DiskUsage> usages = clusterInfo.getNodeLeastAvailableDiskUsages();
         final Decision decision = earlyTerminate(allocation, usages);
         if (decision != null) {
             return decision;
@@ -518,7 +571,7 @@ public Decision canRemain(ShardRouting shardRouting, RoutingNode node, RoutingAl
     private DiskUsageWithRelocations getDiskUsage(
         RoutingNode node,
         RoutingAllocation allocation,
-        ImmutableOpenMap<String, DiskUsage> usages,
+        final Map<String, DiskUsage> usages,
         boolean subtractLeavingShards
     ) {
         DiskUsage usage = usages.get(node.nodeId());
@@ -564,15 +617,15 @@ private DiskUsageWithRelocations getDiskUsage(
      * @param usages Map of nodeId to DiskUsage for all known nodes
      * @return DiskUsage representing given node using the average disk usage
      */
-    DiskUsage averageUsage(RoutingNode node, ImmutableOpenMap<String, DiskUsage> usages) {
+    DiskUsage averageUsage(RoutingNode node, final Map<String, DiskUsage> usages) {
         if (usages.size() == 0) {
             return new DiskUsage(node.nodeId(), node.node().getName(), "_na_", 0, 0);
         }
         long totalBytes = 0;
         long freeBytes = 0;
-        for (ObjectCursor<DiskUsage> du : usages.values()) {
-            totalBytes += du.value.getTotalBytes();
-            freeBytes += du.value.getFreeBytes();
+        for (DiskUsage du : usages.values()) {
+            totalBytes += du.getTotalBytes();
+            freeBytes += du.getFreeBytes();
         }
         return new DiskUsage(node.nodeId(), node.node().getName(), "_na_", totalBytes / usages.size(), freeBytes / usages.size());
     }
@@ -596,7 +649,7 @@ DiskUsage averageUsage(RoutingNode node, ImmutableOpenMap<String, DiskUsage> usa
         return newUsage.getFreeDiskAsPercentage();
     }
 
-    private Decision earlyTerminate(RoutingAllocation allocation, ImmutableOpenMap<String, DiskUsage> usages) {
+    private Decision earlyTerminate(RoutingAllocation allocation, final Map<String, DiskUsage> usages) {
         // Always allow allocation if the decider is disabled
         if (diskThresholdSettings.isEnabled() == false) {
             return allocation.decision(Decision.YES, NAME, "the disk threshold decider is disabled");
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationDecider.java
index bbbf961fe1877..c24346fc0e34e 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationDecider.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import java.util.Locale;
-
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RoutingNode;
@@ -44,6 +42,8 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 
+import java.util.Locale;
+
 /**
  * This allocation decider allows shard allocations / rebalancing via the cluster wide settings
  * {@link #CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING} / {@link #CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING} and the per index setting
@@ -70,6 +70,8 @@
  *
  * @see Rebalance
  * @see Allocation
+ *
+ * @opensearch.internal
  */
 public class EnableAllocationDecider extends AllocationDecider {
 
@@ -280,6 +282,8 @@ private static String setting(Rebalance rebalance, boolean usedIndexSetting) {
      * {@link EnableAllocationDecider#CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING} /
      * {@link EnableAllocationDecider#INDEX_ROUTING_ALLOCATION_ENABLE_SETTING}
      * via cluster / index settings.
+     *
+     * @opensearch.internal
      */
     public enum Allocation {
 
@@ -312,6 +316,8 @@ public String toString() {
      * {@link EnableAllocationDecider#CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING} /
      * {@link EnableAllocationDecider#INDEX_ROUTING_REBALANCE_ENABLE_SETTING}
      * via cluster / index settings.
+     *
+     * @opensearch.internal
      */
     public enum Rebalance {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDecider.java
index cbac924292965..af4b2c61a95b1 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDecider.java
@@ -76,6 +76,8 @@
  * If any {@code exclude} filters are set the allocation is denied if the index is in the set of {@code exclude} filters for the
  * filtered node</li>
  * </ol>
+ *
+ * @opensearch.internal
  */
 public class FilterAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/MaxRetryAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/MaxRetryAllocationDecider.java
index 5c340dbb41112..ccc11be8aa772 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/MaxRetryAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/MaxRetryAllocationDecider.java
@@ -46,6 +46,7 @@
  * Note: This allocation decider also allows allocation of repeatedly failing shards when the {@code /_cluster/reroute?retry_failed=true}
  * API is manually invoked. This allows single retries without raising the limits.
  *
+ * @opensearch.internal
  */
 public class MaxRetryAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeLoadAwareAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeLoadAwareAllocationDecider.java
index 642a16a547519..f26612b5ded8e 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeLoadAwareAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeLoadAwareAllocationDecider.java
@@ -17,8 +17,8 @@
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
 
 import java.util.function.BiPredicate;
 
@@ -33,11 +33,13 @@
  * </pre>
  * <p>
  * and prevent allocation on the surviving nodes of the under capacity cluster
- * based on overload factor defined as a percentage by
+ * based on overload factor defined as a percentage and flat skew as absolute allowed skewness by
+ * </p>
  * <pre>
  * cluster.routing.allocation.load_awareness.skew_factor: X
+ * cluster.routing.allocation.load_awareness.flat_skew: N
  * </pre>
- * The total limit per node based on skew_factor doesn't limit primaries that previously
+ * The total limit per node based on skew_factor and flat_skew doesn't limit primaries that previously
  * existed on the disk as those shards are force allocated by
  * {@link AllocationDeciders#canForceAllocatePrimary(ShardRouting, RoutingNode, RoutingAllocation)}
  * however new primaries due to index creation, snapshot restore etc can be controlled via the below settings.
@@ -47,6 +49,8 @@
  * <pre>
  * cluster.routing.allocation.load_awareness.allow_unassigned_primaries
  * </pre>
+ *
+ * @opensearch.internal
  */
 public class NodeLoadAwareAllocationDecider extends AllocationDecider {
 
@@ -72,6 +76,13 @@ public class NodeLoadAwareAllocationDecider extends AllocationDecider {
         Setting.Property.Dynamic,
         Property.NodeScope
     );
+    public static final Setting<Integer> CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_FLAT_SKEW_SETTING = Setting.intSetting(
+        "cluster.routing.allocation.load_awareness.flat_skew",
+        2,
+        2,
+        Property.Dynamic,
+        Property.NodeScope
+    );
 
     private volatile int provisionedCapacity;
 
@@ -79,12 +90,15 @@ public class NodeLoadAwareAllocationDecider extends AllocationDecider {
 
     private volatile boolean allowUnassignedPrimaries;
 
+    private volatile int flatSkew;
+
     private static final Logger logger = LogManager.getLogger(NodeLoadAwareAllocationDecider.class);
 
     public NodeLoadAwareAllocationDecider(Settings settings, ClusterSettings clusterSettings) {
         this.skewFactor = CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.get(settings);
         this.provisionedCapacity = CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.get(settings);
         this.allowUnassignedPrimaries = CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_ALLOW_UNASSIGNED_PRIMARIES_SETTING.get(settings);
+        this.flatSkew = CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_FLAT_SKEW_SETTING.get(settings);
         clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING, this::setSkewFactor);
         clusterSettings.addSettingsUpdateConsumer(
             CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING,
@@ -94,6 +108,7 @@ public NodeLoadAwareAllocationDecider(Settings settings, ClusterSettings cluster
             CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_ALLOW_UNASSIGNED_PRIMARIES_SETTING,
             this::setAllowUnassignedPrimaries
         );
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_FLAT_SKEW_SETTING, this::setFlatSkew);
     }
 
     private void setAllowUnassignedPrimaries(boolean allowUnassignedPrimaries) {
@@ -108,6 +123,10 @@ private void setProvisionedCapacity(int provisionedCapacity) {
         this.provisionedCapacity = provisionedCapacity;
     }
 
+    private void setFlatSkew(int flatSkew) {
+        this.flatSkew = flatSkew;
+    }
+
     @Override
     public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
         return underCapacity(shardRouting, node, allocation, (count, limit) -> count >= limit);
@@ -144,7 +163,7 @@ private Decision underCapacity(
         Metadata metadata = allocation.metadata();
         float expectedAvgShardsPerNode = (float) metadata.getTotalNumberOfShards() / provisionedCapacity;
         int nodeShardCount = node.numberOfOwningShards();
-        int limit = (int) Math.ceil(expectedAvgShardsPerNode * (1 + skewFactor / 100.0));
+        int limit = flatSkew + (int) Math.ceil(expectedAvgShardsPerNode * (1 + skewFactor / 100.0));
         if (decider.test(nodeShardCount, limit)) {
             logger.debug(
                 () -> new ParameterizedMessage(
@@ -161,10 +180,11 @@ private Decision underCapacity(
                 Decision.NO,
                 NAME,
                 "too many shards [%d] allocated to this node, limit per node [%d] considering"
-                    + " overload factor [%.2f] based on capacity [%d]",
+                    + " overload factor [%.2f] and flat skew [%d] based on capacity [%d]",
                 nodeShardCount,
                 limit,
                 skewFactor,
+                flatSkew,
                 provisionedCapacity
             );
         }
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeVersionAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeVersionAllocationDecider.java
index be95be85ae546..9344b4c87830d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeVersionAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/NodeVersionAllocationDecider.java
@@ -32,12 +32,18 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.indices.replication.common.ReplicationType;
+
+import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * An allocation decider that prevents relocation or allocation from nodes
@@ -45,14 +51,42 @@
  * a newer version than the node we relocate to this might cause {@link org.apache.lucene.index.IndexFormatTooNewException}
  * on the lowest level since it might have already written segments that use a new postings format or codec that is not
  * available on the target node.
+ *
+ * @opensearch.internal
  */
 public class NodeVersionAllocationDecider extends AllocationDecider {
 
     public static final String NAME = "node_version";
 
+    private final ReplicationType replicationType;
+
+    public NodeVersionAllocationDecider(Settings settings) {
+        replicationType = IndexMetadata.INDEX_REPLICATION_TYPE_SETTING.get(settings);
+    }
+
     @Override
     public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
         if (shardRouting.primary()) {
+            if (replicationType == ReplicationType.SEGMENT) {
+                List<ShardRouting> replicas = allocation.routingNodes()
+                    .assignedShards(shardRouting.shardId())
+                    .stream()
+                    .filter(shr -> !shr.primary() && shr.active())
+                    .collect(Collectors.toList());
+                for (ShardRouting replica : replicas) {
+                    // can not allocate if target node version > any existing replica version
+                    RoutingNode replicaNode = allocation.routingNodes().node(replica.currentNodeId());
+                    if (node.node().getVersion().after(replicaNode.node().getVersion())) {
+                        return allocation.decision(
+                            Decision.NO,
+                            NAME,
+                            "When segment replication is enabled, cannot relocate primary shard to a node with version [%s] if it has a replica on older version [%s]",
+                            node.node().getVersion(),
+                            replicaNode.node().getVersion()
+                        );
+                    }
+                }
+            }
             if (shardRouting.currentNodeId() == null) {
                 if (shardRouting.recoverySource() != null && shardRouting.recoverySource().getType() == RecoverySource.Type.SNAPSHOT) {
                     // restoring from a snapshot - check that the node can handle the version
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RebalanceOnlyWhenActiveAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RebalanceOnlyWhenActiveAllocationDecider.java
index c8f32ca40a187..e934a3a6d55b3 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RebalanceOnlyWhenActiveAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RebalanceOnlyWhenActiveAllocationDecider.java
@@ -37,6 +37,8 @@
 
 /**
  * Only allow rebalancing when all shards are active within the shard replication group.
+ *
+ * @opensearch.internal
  */
 public class RebalanceOnlyWhenActiveAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ReplicaAfterPrimaryActiveAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ReplicaAfterPrimaryActiveAllocationDecider.java
index f7300c9e2c6f7..52b89f5c403e8 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ReplicaAfterPrimaryActiveAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ReplicaAfterPrimaryActiveAllocationDecider.java
@@ -38,6 +38,8 @@
 
 /**
  * An allocation strategy that only allows for a replica to be allocated when the primary is active.
+ *
+ * @opensearch.internal
  */
 public class ReplicaAfterPrimaryActiveAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ResizeAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ResizeAllocationDecider.java
index 14f87940b8b50..c5a54739a2494 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ResizeAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ResizeAllocationDecider.java
@@ -38,11 +38,13 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 /**
  * An allocation decider that ensures we allocate the shards of a target index for resize operations next to the source primaries
+ *
+ * @opensearch.internal
  */
 public class ResizeAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDecider.java
index 467a2e0599c92..a9dad1caef60d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDecider.java
@@ -41,6 +41,8 @@
 /**
  * This {@link AllocationDecider} prevents shards that have failed to be
  * restored from a snapshot to be allocated.
+ *
+ * @opensearch.internal
  */
 public class RestoreInProgressAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SameShardAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SameShardAllocationDecider.java
index 58dae82c44f79..1680f2d8cad1d 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SameShardAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SameShardAllocationDecider.java
@@ -35,11 +35,11 @@
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 
 /**
  * An allocation decider that prevents multiple instances of the same shard to
@@ -55,6 +55,8 @@
  * {@code host}. Allocations of multiple copies of the same shard on the same
  * {@code node} are not allowed independently of this setting.
  * </p>
+ *
+ * @opensearch.internal
  */
 public class SameShardAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ShardsLimitAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ShardsLimitAllocationDecider.java
index ef8c8ba7c057a..c008102554e8c 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ShardsLimitAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ShardsLimitAllocationDecider.java
@@ -63,6 +63,8 @@
  * Note: Reducing the number of shards per node via the index update API can
  * trigger relocation and significant additional load on the clusters nodes.
  * </p>
+ *
+ * @opensearch.internal
  */
 public class ShardsLimitAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SnapshotInProgressAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SnapshotInProgressAllocationDecider.java
index 25150bf603f32..c55365c43d23a 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SnapshotInProgressAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/SnapshotInProgressAllocationDecider.java
@@ -42,6 +42,8 @@
 /**
  * This {@link AllocationDecider} prevents shards that
  * are currently been snapshotted to be moved to other nodes.
+ *
+ * @opensearch.internal
  */
 public class SnapshotInProgressAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDecider.java
new file mode 100644
index 0000000000000..c11f5823cf3a7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDecider.java
@@ -0,0 +1,141 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation.decider;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingPool;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+
+/**
+ * {@link TargetPoolAllocationDecider} ensures that the different shard types are assigned to the nodes with
+ * appropriate capabilities. The node pools with respective capabilities are defined within {@link RoutingPool}.
+ *
+ * @opensearch.internal
+ */
+public class TargetPoolAllocationDecider extends AllocationDecider {
+    private static final Logger logger = LogManager.getLogger(TargetPoolAllocationDecider.class);
+
+    public static final String NAME = "target_pool";
+
+    @Override
+    public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
+        RoutingPool shardPool = RoutingPool.getShardPool(shardRouting, allocation);
+        RoutingPool targetNodePool = RoutingPool.getNodePool(node);
+        if (RoutingPool.REMOTE_CAPABLE.equals(shardPool) && RoutingPool.LOCAL_ONLY.equals(targetNodePool)) {
+            logger.debug(
+                "Shard: [{}] has target pool: [{}]. Cannot allocate on node: [{}] with target pool: [{}]",
+                shardRouting,
+                shardPool,
+                node.node(),
+                targetNodePool
+            );
+            return allocation.decision(
+                Decision.NO,
+                NAME,
+                "Routing pools are incompatible. Shard pool: [%s], Node Pool: [%s]",
+                shardPool,
+                targetNodePool
+            );
+        } else if (RoutingPool.LOCAL_ONLY.equals(shardPool)
+            && RoutingPool.REMOTE_CAPABLE.equals(targetNodePool)
+            && !node.node().getRoles().contains(DiscoveryNodeRole.DATA_ROLE)) {
+                logger.debug(
+                    "Shard: [{}] has target pool: [{}]. Cannot allocate on node: [{}] without the [{}] node role",
+                    shardRouting,
+                    shardPool,
+                    node.node(),
+                    DiscoveryNodeRole.DATA_ROLE
+                );
+                return allocation.decision(
+                    Decision.NO,
+                    NAME,
+                    "Routing pools are incompatible. Shard pool: [{}], Node Pool: [{}] without [{}] role",
+                    shardPool,
+                    targetNodePool,
+                    DiscoveryNodeRole.DATA_ROLE
+                );
+            }
+        return allocation.decision(
+            Decision.YES,
+            NAME,
+            "Routing pools are compatible. Shard pool: [%s], Node Pool: [%s]",
+            shardPool,
+            targetNodePool
+        );
+    }
+
+    @Override
+    public Decision canAllocate(IndexMetadata indexMetadata, RoutingNode node, RoutingAllocation allocation) {
+        return canAllocateInTargetPool(indexMetadata, node.node(), allocation);
+    }
+
+    @Override
+    public Decision canForceAllocatePrimary(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
+        logger.debug("Evaluating force allocation for primary shard.");
+        return canAllocate(shardRouting, node, allocation);
+    }
+
+    public Decision shouldAutoExpandToNode(IndexMetadata indexMetadata, DiscoveryNode node, RoutingAllocation allocation) {
+        logger.debug("Evaluating node: {} for autoExpandReplica eligibility of index: {}", node, indexMetadata.getIndex());
+        return canAllocateInTargetPool(indexMetadata, node, allocation);
+    }
+
+    private Decision canAllocateInTargetPool(IndexMetadata indexMetadata, DiscoveryNode node, RoutingAllocation allocation) {
+        RoutingPool indexPool = RoutingPool.getIndexPool(indexMetadata);
+        RoutingPool targetNodePool = RoutingPool.getNodePool(node);
+        if (RoutingPool.REMOTE_CAPABLE.equals(indexPool) && RoutingPool.LOCAL_ONLY.equals(targetNodePool)) {
+            logger.debug(
+                "Index: [{}] has target pool: [{}]. Cannot allocate on node: [{}] with target pool: [{}]",
+                indexMetadata.getIndex().getName(),
+                indexPool,
+                node,
+                targetNodePool
+            );
+            return allocation.decision(
+                Decision.NO,
+                NAME,
+                "Routing pools are incompatible. Index pool: [%s], Node Pool: [%s]",
+                indexPool,
+                targetNodePool
+            );
+        } else if (RoutingPool.LOCAL_ONLY.equals(indexPool)
+            && RoutingPool.REMOTE_CAPABLE.equals(targetNodePool)
+            && !node.getRoles().contains(DiscoveryNodeRole.DATA_ROLE)) {
+                logger.debug(
+                    "Index: [{}] has target pool: [{}]. Cannot allocate on node: [{}] without the [{}] node role",
+                    indexMetadata.getIndex().getName(),
+                    indexPool,
+                    node,
+                    DiscoveryNodeRole.DATA_ROLE
+                );
+                return allocation.decision(
+                    Decision.NO,
+                    NAME,
+                    "Routing pools are incompatible. Index pool: [{}], Node Pool: [{}] without [{}] role",
+                    indexPool,
+                    targetNodePool,
+                    DiscoveryNodeRole.DATA_ROLE
+                );
+            }
+        return allocation.decision(
+            Decision.YES,
+            NAME,
+            "Routing pools are compatible. Index pool: [%s], Node Pool: [%s]",
+            indexPool,
+            targetNodePool
+        );
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ThrottlingAllocationDecider.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ThrottlingAllocationDecider.java
index a745f5c498fee..3a9fdf0ea10cf 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ThrottlingAllocationDecider.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/ThrottlingAllocationDecider.java
@@ -68,6 +68,8 @@
  * will return {@link Decision#THROTTLE} as a hit to upstream logic to throttle
  * the allocation process to prevent overloading nodes due to too many concurrent recovery
  * processes.
+ *
+ * @opensearch.internal
  */
 public class ThrottlingAllocationDecider extends AllocationDecider {
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/package-info.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/package-info.java
new file mode 100644
index 0000000000000..9429cb35c8adf
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/decider/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Foundation Classes to Decide how to allocate and balance shards */
+package org.opensearch.cluster.routing.allocation.decider;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/package-info.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/package-info.java
new file mode 100644
index 0000000000000..2f274f997f907
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Shard Allocation Foundation Classes. */
+package org.opensearch.cluster.routing.allocation;
diff --git a/server/src/main/java/org/opensearch/cluster/routing/package-info.java b/server/src/main/java/org/opensearch/cluster/routing/package-info.java
new file mode 100644
index 0000000000000..91989d2bc9c80
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/routing/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster level shard routing and recovery classes. */
+package org.opensearch.cluster.routing;
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterApplier.java b/server/src/main/java/org/opensearch/cluster/service/ClusterApplier.java
index 34ce20a234a33..939feb89b6054 100644
--- a/server/src/main/java/org/opensearch/cluster/service/ClusterApplier.java
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterApplier.java
@@ -36,6 +36,11 @@
 
 import java.util.function.Supplier;
 
+/**
+ * Interface to monitor when cluster state changes
+ *
+ * @opensearch.internal
+ */
 public interface ClusterApplier {
     /**
      * Sets the initial state for this applier. Should only be called once.
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterApplierService.java b/server/src/main/java/org/opensearch/cluster/service/ClusterApplierService.java
index 20f8c0a00e32b..007508162ba14 100644
--- a/server/src/main/java/org/opensearch/cluster/service/ClusterApplierService.java
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterApplierService.java
@@ -41,6 +41,7 @@
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.ClusterStateTaskConfig;
+import org.opensearch.cluster.LocalNodeClusterManagerListener;
 import org.opensearch.cluster.LocalNodeMasterListener;
 import org.opensearch.cluster.NodeConnectionsService;
 import org.opensearch.cluster.TimeoutClusterStateListener;
@@ -49,16 +50,16 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
 import org.opensearch.common.StopWatch;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.StopWatch.TimingHandle;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -78,6 +79,11 @@
 
 import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
 
+/**
+ * Service that provides callbacks when cluster state changes
+ *
+ * @opensearch.internal
+ */
 public class ClusterApplierService extends AbstractLifecycleComponent implements ClusterApplier {
     private static final Logger logger = LogManager.getLogger(ClusterApplierService.class);
 
@@ -270,12 +276,21 @@ public void removeTimeoutListener(TimeoutClusterStateListener listener) {
     }
 
     /**
-     * Add a listener for on/off local node master events
+     * Add a listener for on/off local node cluster-manager events
      */
-    public void addLocalNodeMasterListener(LocalNodeMasterListener listener) {
+    public void addLocalNodeClusterManagerListener(LocalNodeClusterManagerListener listener) {
         addListener(listener);
     }
 
+    /**
+     * Add a listener for on/off local node cluster-manager events
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #addLocalNodeClusterManagerListener}
+     */
+    @Deprecated
+    public void addLocalNodeMasterListener(LocalNodeMasterListener listener) {
+        addLocalNodeClusterManagerListener(listener);
+    }
+
     /**
      * Adds a cluster state listener that is expected to be removed during a short period of time.
      * If provided, the listener will be notified once a specific time has elapsed.
@@ -429,7 +444,7 @@ private void runTask(UpdateTask task) {
         final StopWatch stopWatch = new StopWatch();
         final ClusterState newClusterState;
         try {
-            try (Releasable ignored = stopWatch.timing("running task [" + task.source + ']')) {
+            try (TimingHandle ignored = stopWatch.timing("running task [" + task.source + ']')) {
                 newClusterState = task.apply(previousClusterState);
             }
         } catch (Exception e) {
@@ -529,7 +544,7 @@ private void applyChanges(UpdateTask task, ClusterState previousClusterState, Cl
         }
 
         logger.trace("connecting to nodes of cluster state with version {}", newClusterState.version());
-        try (Releasable ignored = stopWatch.timing("connecting to new nodes")) {
+        try (TimingHandle ignored = stopWatch.timing("connecting to new nodes")) {
             connectToNodesAndWait(newClusterState);
         }
 
@@ -537,7 +552,7 @@ private void applyChanges(UpdateTask task, ClusterState previousClusterState, Cl
         if (clusterChangedEvent.state().blocks().disableStatePersistence() == false && clusterChangedEvent.metadataChanged()) {
             logger.debug("applying settings from cluster state with version {}", newClusterState.version());
             final Settings incomingSettings = clusterChangedEvent.state().metadata().settings();
-            try (Releasable ignored = stopWatch.timing("applying settings")) {
+            try (TimingHandle ignored = stopWatch.timing("applying settings")) {
                 clusterSettings.applySettings(incomingSettings);
             }
         }
@@ -587,7 +602,7 @@ private static void callClusterStateAppliers(
     ) {
         for (ClusterStateApplier applier : clusterStateAppliers) {
             logger.trace("calling [{}] with change to version [{}]", applier, clusterChangedEvent.state().version());
-            try (Releasable ignored = stopWatch.timing("running applier [" + applier + "]")) {
+            try (TimingHandle ignored = stopWatch.timing("running applier [" + applier + "]")) {
                 applier.applyClusterState(clusterChangedEvent);
             }
         }
@@ -606,7 +621,7 @@ private void callClusterStateListener(
         for (ClusterStateListener listener : listeners) {
             try {
                 logger.trace("calling [{}] with change to version [{}]", listener, clusterChangedEvent.state().version());
-                try (Releasable ignored = stopWatch.timing("notifying listener [" + listener + "]")) {
+                try (TimingHandle ignored = stopWatch.timing("notifying listener [" + listener + "]")) {
                     listener.clusterChanged(clusterChangedEvent);
                 }
             } catch (Exception ex) {
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerService.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerService.java
new file mode 100644
index 0000000000000..74b623dd95e6f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerService.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.threadpool.ThreadPool;
+
+/**
+ * Main Cluster Manager Node Service
+ *
+ * @opensearch.internal
+ */
+public class ClusterManagerService extends MasterService {
+    public ClusterManagerService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
+        super(settings, clusterSettings, threadPool);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskKeys.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskKeys.java
new file mode 100644
index 0000000000000..c88bea56cb9bd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskKeys.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+/**
+ * Class for maintaining all cluster manager task key at one place.
+ */
+public final class ClusterManagerTaskKeys {
+
+    public static final String CREATE_INDEX_KEY = "create-index";
+    public static final String UPDATE_SETTINGS_KEY = "update-settings";
+    public static final String CLUSTER_UPDATE_SETTINGS_KEY = "cluster-update-settings";
+    public static final String AUTO_CREATE_KEY = "auto-create";
+    public static final String DELETE_INDEX_KEY = "delete-index";
+    public static final String DELETE_DANGLING_INDEX_KEY = "delete-dangling-index";
+    public static final String CREATE_DATA_STREAM_KEY = "create-data-stream";
+    public static final String REMOVE_DATA_STREAM_KEY = "remove-data-stream";
+    public static final String ROLLOVER_INDEX_KEY = "rollover-index";
+    public static final String INDEX_ALIASES_KEY = "index-aliases";
+    public static final String PUT_MAPPING_KEY = "put-mapping";
+    public static final String CREATE_INDEX_TEMPLATE_KEY = "create-index-template";
+    public static final String REMOVE_INDEX_TEMPLATE_KEY = "remove-index-template";
+    public static final String CREATE_COMPONENT_TEMPLATE_KEY = "create-component-template";
+    public static final String REMOVE_COMPONENT_TEMPLATE_KEY = "remove-component-template";
+    public static final String CREATE_INDEX_TEMPLATE_V2_KEY = "create-index-template-v2";
+    public static final String REMOVE_INDEX_TEMPLATE_V2_KEY = "remove-index-template-v2";
+    public static final String PUT_PIPELINE_KEY = "put-pipeline";
+    public static final String DELETE_PIPELINE_KEY = "delete-pipeline";
+
+    public static final String PUT_SEARCH_PIPELINE_KEY = "put-search-pipeline";
+    public static final String DELETE_SEARCH_PIPELINE_KEY = "delete-search-pipeline";
+    public static final String CREATE_PERSISTENT_TASK_KEY = "create-persistent-task";
+    public static final String FINISH_PERSISTENT_TASK_KEY = "finish-persistent-task";
+    public static final String REMOVE_PERSISTENT_TASK_KEY = "remove-persistent-task";
+    public static final String UPDATE_TASK_STATE_KEY = "update-task-state";
+    public static final String PUT_SCRIPT_KEY = "put-script";
+    public static final String DELETE_SCRIPT_KEY = "delete-script";
+    public static final String PUT_REPOSITORY_KEY = "put-repository";
+    public static final String DELETE_REPOSITORY_KEY = "delete-repository";
+    public static final String CREATE_SNAPSHOT_KEY = "create-snapshot";
+    public static final String DELETE_SNAPSHOT_KEY = "delete-snapshot";
+    public static final String UPDATE_SNAPSHOT_STATE_KEY = "update-snapshot-state";
+    public static final String RESTORE_SNAPSHOT_KEY = "restore-snapshot";
+    public static final String CLUSTER_REROUTE_API_KEY = "cluster-reroute-api";
+
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottler.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottler.java
new file mode 100644
index 0000000000000..8da6b1b941f83
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottler.java
@@ -0,0 +1,281 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterStateTaskExecutor;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
+
+/**
+ * This class does throttling on task submission to cluster manager node, it uses throttling key defined in various executors
+ * as key for throttling. Throttling will be performed over task executor's class level, different task types have different executors class.
+ *
+ * Set specific setting to for setting the threshold of throttling of particular task type.
+ * e.g : Set "cluster_manager.throttling.thresholds.put_mapping" to set throttling limit of "put mapping" tasks,
+ *       Set it to default value(-1) to disable the throttling for this task type.
+ */
+public class ClusterManagerTaskThrottler implements TaskBatcherListener {
+    private static final Logger logger = LogManager.getLogger(ClusterManagerTaskThrottler.class);
+    public static final ThrottlingKey DEFAULT_THROTTLING_KEY = new ThrottlingKey("default-task-key", false);
+
+    // default value for base delay is 5s
+    static volatile TimeValue baseDelay = TimeValue.timeValueSeconds(5);
+    // default values for max delay is 30s
+    static volatile TimeValue maxDelay = TimeValue.timeValueSeconds(30);
+
+    public static final Setting<Settings> THRESHOLD_SETTINGS = Setting.groupSetting(
+        "cluster_manager.throttling.thresholds.",
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<TimeValue> BASE_DELAY_SETTINGS = Setting.timeSetting(
+        "cluster_manager.throttling.retry.base.delay",
+        baseDelay,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<TimeValue> MAX_DELAY_SETTINGS = Setting.timeSetting(
+        "cluster_manager.throttling.retry.max.delay",
+        maxDelay,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    protected Map<String, ThrottlingKey> THROTTLING_TASK_KEYS = new ConcurrentHashMap<>();
+
+    private final int MIN_THRESHOLD_VALUE = -1; // Disabled throttling
+    private final ClusterManagerTaskThrottlerListener clusterManagerTaskThrottlerListener;
+
+    private final ConcurrentMap<String, Long> tasksCount;
+    private final ConcurrentMap<String, Long> tasksThreshold;
+    private final Supplier<Version> minNodeVersionSupplier;
+
+    // Once all nodes are greater than or equal 2.5.0 version, then only it will start throttling.
+    // During upgrade as well, it will wait for all older version nodes to leave the cluster before starting throttling.
+    // This is needed specifically for static setting to enable throttling.
+    private AtomicBoolean startThrottling = new AtomicBoolean();
+
+    public ClusterManagerTaskThrottler(
+        final Settings settings,
+        final ClusterSettings clusterSettings,
+        final Supplier<Version> minNodeVersionSupplier,
+        final ClusterManagerTaskThrottlerListener clusterManagerTaskThrottlerListener
+    ) {
+        tasksCount = new ConcurrentHashMap<>(128); // setting initial capacity so each task will land in different segment
+        tasksThreshold = new ConcurrentHashMap<>(128); // setting initial capacity so each task will land in different segment
+        this.minNodeVersionSupplier = minNodeVersionSupplier;
+        this.clusterManagerTaskThrottlerListener = clusterManagerTaskThrottlerListener;
+        clusterSettings.addSettingsUpdateConsumer(THRESHOLD_SETTINGS, this::updateSetting, this::validateSetting);
+        clusterSettings.addSettingsUpdateConsumer(BASE_DELAY_SETTINGS, this::updateBaseDelay);
+        clusterSettings.addSettingsUpdateConsumer(MAX_DELAY_SETTINGS, this::updateMaxDelay);
+        // Required for setting values as per current settings during node bootstrap
+        updateSetting(THRESHOLD_SETTINGS.get(settings));
+        updateBaseDelay(BASE_DELAY_SETTINGS.get(settings));
+        updateMaxDelay(MAX_DELAY_SETTINGS.get(settings));
+    }
+
+    void updateBaseDelay(TimeValue newBaseValue) {
+        baseDelay = newBaseValue;
+    }
+
+    void updateMaxDelay(TimeValue newMaxValue) {
+        maxDelay = newMaxValue;
+    }
+
+    public static TimeValue getBaseDelayForRetry() {
+        return baseDelay;
+    }
+
+    public static TimeValue getMaxDelayForRetry() {
+        return maxDelay;
+    }
+
+    /**
+     * To configure a new task for throttling,
+     * * Register task to cluster service with task key,
+     * * override getClusterManagerThrottlingKey method with above task key in task executor.
+     * * Verify that throttled tasks would be retried from data nodes
+     *
+     * Added retry mechanism in TransportClusterManagerNodeAction, so it would be retried for customer generated tasks.
+     *
+     * If tasks are not getting retried then we can register with false flag, so user won't be able to configure threshold limits for it.
+     */
+    protected ThrottlingKey registerClusterManagerTask(String taskKey, boolean throttlingEnabled) {
+        ThrottlingKey throttlingKey = new ThrottlingKey(taskKey, throttlingEnabled);
+        if (THROTTLING_TASK_KEYS.containsKey(taskKey)) {
+            throw new IllegalArgumentException("There is already a Throttling key registered with same name: " + taskKey);
+        }
+        THROTTLING_TASK_KEYS.put(taskKey, throttlingKey);
+        return throttlingKey;
+    }
+
+    /**
+     * Class to store the throttling key for the tasks of cluster manager
+     */
+    public static class ThrottlingKey {
+        private String taskThrottlingKey;
+        private boolean throttlingEnabled;
+
+        /**
+         * Class for throttling key of tasks
+         *
+         * @param taskThrottlingKey - throttling key for task
+         * @param throttlingEnabled - if throttling is enabled or not i.e. data node is performing retry over throttling exception or not.
+         */
+        private ThrottlingKey(String taskThrottlingKey, boolean throttlingEnabled) {
+            this.taskThrottlingKey = taskThrottlingKey;
+            this.throttlingEnabled = throttlingEnabled;
+        }
+
+        public String getTaskThrottlingKey() {
+            return taskThrottlingKey;
+        }
+
+        public boolean isThrottlingEnabled() {
+            return throttlingEnabled;
+        }
+    }
+
+    void validateSetting(final Settings settings) {
+        Map<String, Settings> groups = settings.getAsGroups();
+        if (groups.size() > 0) {
+            if (minNodeVersionSupplier.get().compareTo(Version.V_2_5_0) < 0) {
+                throw new IllegalArgumentException("All the nodes in cluster should be on version later than or equal to 2.5.0");
+            }
+        }
+        for (String key : groups.keySet()) {
+            if (!THROTTLING_TASK_KEYS.containsKey(key)) {
+                throw new IllegalArgumentException("Cluster manager task throttling is not configured for given task type: " + key);
+            }
+            if (!THROTTLING_TASK_KEYS.get(key).isThrottlingEnabled()) {
+                throw new IllegalArgumentException("Throttling is not enabled for given task type: " + key);
+            }
+            int threshold = groups.get(key).getAsInt("value", MIN_THRESHOLD_VALUE);
+            if (threshold < MIN_THRESHOLD_VALUE) {
+                throw new IllegalArgumentException("Provide positive integer for limit or -1 for disabling throttling");
+            }
+        }
+    }
+
+    void updateSetting(final Settings newSettings) {
+        Map<String, Settings> groups = newSettings.getAsGroups();
+        Set<String> settingKeys = new HashSet<>();
+        // Adding keys which are present in new Setting
+        settingKeys.addAll(groups.keySet());
+        // Adding existing keys that may need to be set to a default value if that is removed in new setting.
+        settingKeys.addAll(tasksThreshold.keySet());
+        for (String key : settingKeys) {
+            Settings setting = groups.get(key);
+            updateLimit(key, setting == null ? MIN_THRESHOLD_VALUE : setting.getAsInt("value", MIN_THRESHOLD_VALUE));
+        }
+    }
+
+    void updateLimit(final String taskKey, final int limit) {
+        assert limit >= MIN_THRESHOLD_VALUE;
+        if (limit == MIN_THRESHOLD_VALUE) {
+            tasksThreshold.remove(taskKey);
+        } else {
+            tasksThreshold.put(taskKey, (long) limit);
+        }
+    }
+
+    Long getThrottlingLimit(final String taskKey) {
+        return tasksThreshold.get(taskKey);
+    }
+
+    @Override
+    public void onBeginSubmit(List<? extends TaskBatcher.BatchedTask> tasks) {
+        ThrottlingKey clusterManagerThrottlingKey = ((ClusterStateTaskExecutor<Object>) tasks.get(0).batchingKey)
+            .getClusterManagerThrottlingKey();
+        tasksCount.putIfAbsent(clusterManagerThrottlingKey.getTaskThrottlingKey(), 0L);
+        tasksCount.computeIfPresent(clusterManagerThrottlingKey.getTaskThrottlingKey(), (key, count) -> {
+            int size = tasks.size();
+            if (clusterManagerThrottlingKey.isThrottlingEnabled()) {
+                Long threshold = tasksThreshold.get(clusterManagerThrottlingKey.getTaskThrottlingKey());
+                if (threshold != null && shouldThrottle(threshold, count, size)) {
+                    clusterManagerTaskThrottlerListener.onThrottle(clusterManagerThrottlingKey.getTaskThrottlingKey(), size);
+                    logger.warn(
+                        "Throwing Throttling Exception for [{}]. Trying to add [{}] tasks to queue, limit is set to [{}]",
+                        clusterManagerThrottlingKey.getTaskThrottlingKey(),
+                        tasks.size(),
+                        threshold
+                    );
+                    throw new ClusterManagerThrottlingException(
+                        "Throttling Exception : Limit exceeded for " + clusterManagerThrottlingKey.getTaskThrottlingKey()
+                    );
+                }
+            }
+            return count + size;
+        });
+    }
+
+    /**
+     * If throttling thresholds are set via static setting, it will update the threshold map.
+     * It may start throwing throttling exception to older nodes in cluster.
+     * Older version nodes will not be equipped to handle the throttling exception and
+     * this may result in unexpected behavior where internal tasks would start failing without any retries.
+     *
+     * For every task submission request, it will validate if nodes version is greater or equal to 2.5.0 and set the startThrottling flag.
+     * Once the startThrottling flag is set, it will not perform check for next set of tasks.
+     */
+    private boolean shouldThrottle(Long threshold, Long count, int size) {
+        if (!startThrottling.get()) {
+            if (minNodeVersionSupplier.get().compareTo(Version.V_2_5_0) >= 0) {
+                startThrottling.compareAndSet(false, true);
+                logger.info("Starting cluster manager throttling as all nodes are higher than or equal to 2.5.0");
+            } else {
+                logger.info("Skipping cluster manager throttling as at least one node < 2.5.0 is present in cluster");
+                return false;
+            }
+        }
+        return count + size > threshold;
+    }
+
+    @Override
+    public void onSubmitFailure(List<? extends TaskBatcher.BatchedTask> tasks) {
+        reduceTaskCount(tasks);
+    }
+
+    /**
+     * Tasks will be removed from the queue before processing, so here we will reduce the count of tasks.
+     *
+     * @param tasks list of tasks which will be executed.
+     */
+    @Override
+    public void onBeginProcessing(List<? extends TaskBatcher.BatchedTask> tasks) {
+        reduceTaskCount(tasks);
+    }
+
+    @Override
+    public void onTimeout(List<? extends TaskBatcher.BatchedTask> tasks) {
+        reduceTaskCount(tasks);
+    }
+
+    private void reduceTaskCount(List<? extends TaskBatcher.BatchedTask> tasks) {
+        String masterTaskKey = ((ClusterStateTaskExecutor<Object>) tasks.get(0).batchingKey).getClusterManagerThrottlingKey()
+            .getTaskThrottlingKey();
+        tasksCount.computeIfPresent(masterTaskKey, (key, count) -> count - tasks.size());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerListener.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerListener.java
new file mode 100644
index 0000000000000..9d41f4d39b09f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerListener.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+/**
+ * Listener interface for master task throttling
+ */
+public interface ClusterManagerTaskThrottlerListener {
+    void onThrottle(String type, final int counts);
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingException.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingException.java
new file mode 100644
index 0000000000000..04fa9fa45d5ea
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingException.java
@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+/**
+ * Exception raised from cluster manager node due to task throttling.
+ */
+public class ClusterManagerThrottlingException extends OpenSearchException {
+
+    public ClusterManagerThrottlingException(String msg, Object... args) {
+        super(msg, args);
+    }
+
+    public ClusterManagerThrottlingException(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingStats.java b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingStats.java
new file mode 100644
index 0000000000000..7714b608c7c12
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterManagerThrottlingStats.java
@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Contains stats of Cluster Manager Task Throttling.
+ * It stores the total cumulative count of throttled tasks per task type.
+ */
+public class ClusterManagerThrottlingStats implements ClusterManagerTaskThrottlerListener, Writeable, ToXContentFragment {
+
+    private Map<String, CounterMetric> throttledTasksCount;
+
+    public ClusterManagerThrottlingStats() {
+        throttledTasksCount = new ConcurrentHashMap<>();
+    }
+
+    private void incrementThrottlingCount(String type, final int counts) {
+        throttledTasksCount.computeIfAbsent(type, k -> new CounterMetric()).inc(counts);
+    }
+
+    public long getThrottlingCount(String type) {
+        return throttledTasksCount.get(type) == null ? 0 : throttledTasksCount.get(type).count();
+    }
+
+    public long getTotalThrottledTaskCount() {
+        CounterMetric totalCount = new CounterMetric();
+        throttledTasksCount.forEach((aClass, counterMetric) -> { totalCount.inc(counterMetric.count()); });
+        return totalCount.count();
+    }
+
+    @Override
+    public void onThrottle(String type, int counts) {
+        incrementThrottlingCount(type, counts);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVInt(throttledTasksCount.size());
+        for (Map.Entry<String, CounterMetric> entry : throttledTasksCount.entrySet()) {
+            out.writeString(entry.getKey());
+            out.writeVInt((int) entry.getValue().count());
+        }
+    }
+
+    public ClusterManagerThrottlingStats(StreamInput in) throws IOException {
+        int throttledTaskEntries = in.readVInt();
+        throttledTasksCount = new ConcurrentHashMap<>();
+        for (int i = 0; i < throttledTaskEntries; i++) {
+            String taskType = in.readString();
+            int throttledTaskCount = in.readVInt();
+            onThrottle(taskType, throttledTaskCount);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject("cluster_manager_throttling");
+        builder.startObject("stats");
+        builder.field("total_throttled_tasks", getTotalThrottledTaskCount());
+        builder.startObject("throttled_tasks_per_task_type");
+        for (Map.Entry<String, CounterMetric> entry : throttledTasksCount.entrySet()) {
+            builder.field(entry.getKey(), entry.getValue().count());
+        }
+        builder.endObject();
+        builder.endObject();
+        return builder.endObject();
+    }
+
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        } else if (o != null && this.getClass() == o.getClass()) {
+            ClusterManagerThrottlingStats that = (ClusterManagerThrottlingStats) o;
+
+            if (this.throttledTasksCount.size() == that.throttledTasksCount.size()) {
+                for (Map.Entry<String, CounterMetric> entry : this.throttledTasksCount.entrySet()) {
+                    if (that.throttledTasksCount.get(entry.getKey()).count() != entry.getValue().count()) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public int hashCode() {
+        Map<String, Long> countMap = new ConcurrentHashMap<>();
+        for (Map.Entry<String, CounterMetric> entry : this.throttledTasksCount.entrySet()) {
+            countMap.put(entry.getKey(), entry.getValue().count());
+        }
+        return countMap.hashCode();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/ClusterService.java b/server/src/main/java/org/opensearch/cluster/service/ClusterService.java
index 46d65f310a427..aa7766979e851 100644
--- a/server/src/main/java/org/opensearch/cluster/service/ClusterService.java
+++ b/server/src/main/java/org/opensearch/cluster/service/ClusterService.java
@@ -39,12 +39,14 @@
 import org.opensearch.cluster.ClusterStateTaskConfig;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.ClusterStateTaskListener;
+import org.opensearch.cluster.LocalNodeClusterManagerListener;
 import org.opensearch.cluster.LocalNodeMasterListener;
 import org.opensearch.cluster.NodeConnectionsService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.cluster.routing.RerouteService;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
@@ -56,8 +58,14 @@
 import java.util.Collections;
 import java.util.Map;
 
+/**
+ * Main Cluster Service
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class ClusterService extends AbstractLifecycleComponent {
-    private final MasterService masterService;
+    private final ClusterManagerService clusterManagerService;
 
     private final ClusterApplierService clusterApplierService;
 
@@ -87,7 +95,7 @@ public ClusterService(Settings settings, ClusterSettings clusterSettings, Thread
         this(
             settings,
             clusterSettings,
-            new MasterService(settings, clusterSettings, threadPool),
+            new ClusterManagerService(settings, clusterSettings, threadPool),
             new ClusterApplierService(Node.NODE_NAME_SETTING.get(settings), settings, clusterSettings, threadPool)
         );
     }
@@ -95,12 +103,12 @@ public ClusterService(Settings settings, ClusterSettings clusterSettings, Thread
     public ClusterService(
         Settings settings,
         ClusterSettings clusterSettings,
-        MasterService masterService,
+        ClusterManagerService clusterManagerService,
         ClusterApplierService clusterApplierService
     ) {
         this.settings = settings;
         this.nodeName = Node.NODE_NAME_SETTING.get(settings);
-        this.masterService = masterService;
+        this.clusterManagerService = clusterManagerService;
         this.operationRouting = new OperationRouting(settings, clusterSettings);
         this.clusterSettings = clusterSettings;
         this.clusterName = ClusterName.CLUSTER_NAME_SETTING.get(settings);
@@ -126,18 +134,18 @@ public RerouteService getRerouteService() {
     @Override
     protected synchronized void doStart() {
         clusterApplierService.start();
-        masterService.start();
+        clusterManagerService.start();
     }
 
     @Override
     protected synchronized void doStop() {
-        masterService.stop();
+        clusterManagerService.stop();
         clusterApplierService.stop();
     }
 
     @Override
     protected synchronized void doClose() {
-        masterService.close();
+        clusterManagerService.close();
         clusterApplierService.close();
     }
 
@@ -207,14 +215,29 @@ public void removeListener(ClusterStateListener listener) {
     }
 
     /**
-     * Add a listener for on/off local node master events
+     * Add a listener for on/off local node cluster-manager events
      */
+    public void addLocalNodeClusterManagerListener(LocalNodeClusterManagerListener listener) {
+        clusterApplierService.addLocalNodeClusterManagerListener(listener);
+    }
+
+    /**
+     * Add a listener for on/off local node cluster-manager events
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #addLocalNodeClusterManagerListener}
+     */
+    @Deprecated
     public void addLocalNodeMasterListener(LocalNodeMasterListener listener) {
-        clusterApplierService.addLocalNodeMasterListener(listener);
+        addLocalNodeClusterManagerListener(listener);
+    }
+
+    public ClusterManagerService getClusterManagerService() {
+        return clusterManagerService;
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerService()} */
+    @Deprecated
     public MasterService getMasterService() {
-        return masterService;
+        return clusterManagerService;
     }
 
     /**
@@ -235,13 +258,19 @@ public ClusterApplierService getClusterApplierService() {
         return clusterApplierService;
     }
 
-    public static boolean assertClusterOrMasterStateThread() {
+    public static boolean assertClusterOrClusterManagerStateThread() {
         assert Thread.currentThread().getName().contains(ClusterApplierService.CLUSTER_UPDATE_THREAD_NAME)
-            || Thread.currentThread().getName().contains(MasterService.MASTER_UPDATE_THREAD_NAME)
+            || Thread.currentThread().getName().contains(ClusterManagerService.CLUSTER_MANAGER_UPDATE_THREAD_NAME)
             : "not called from the master/cluster state update thread";
         return true;
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #assertClusterOrClusterManagerStateThread} */
+    @Deprecated
+    public static boolean assertClusterOrMasterStateThread() {
+        return assertClusterOrClusterManagerStateThread();
+    }
+
     public ClusterName getClusterName() {
         return clusterName;
     }
@@ -264,6 +293,17 @@ public final String getNodeName() {
         return nodeName;
     }
 
+    /**
+     * Functionality for register task key to cluster manager node.
+     *
+     * @param taskKey - task key of task
+     * @param throttlingEnabled - throttling is enabled for task or not i.e does data node perform retries on it or not
+     * @return throttling task key which needs to be passed while submitting task to cluster manager
+     */
+    public ClusterManagerTaskThrottler.ThrottlingKey registerClusterManagerTask(String taskKey, boolean throttlingEnabled) {
+        return clusterManagerService.registerClusterManagerTask(taskKey, throttlingEnabled);
+    }
+
     /**
      * Submits a cluster state update task; unlike {@link #submitStateUpdateTask(String, Object, ClusterStateTaskConfig,
      * ClusterStateTaskExecutor, ClusterStateTaskListener)}, submitted updates will not be batched.
@@ -328,6 +368,6 @@ public <T> void submitStateUpdateTasks(
         final ClusterStateTaskConfig config,
         final ClusterStateTaskExecutor<T> executor
     ) {
-        masterService.submitStateUpdateTasks(source, tasks, config, executor);
+        clusterManagerService.submitStateUpdateTasks(source, tasks, config, executor);
     }
 }
diff --git a/server/src/main/java/org/opensearch/cluster/service/MasterService.java b/server/src/main/java/org/opensearch/cluster/service/MasterService.java
index ad0bc599420f1..563b69dfd0e2a 100644
--- a/server/src/main/java/org/opensearch/cluster/service/MasterService.java
+++ b/server/src/main/java/org/opensearch/cluster/service/MasterService.java
@@ -35,7 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.Assertions;
+import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.AckedClusterStateTaskListener;
 import org.opensearch.cluster.ClusterChangedEvent;
@@ -54,18 +54,19 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.node.Node;
 import org.opensearch.threadpool.Scheduler;
@@ -83,6 +84,13 @@
 
 import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
 
+/**
+ * Main Master Node Service
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link ClusterManagerService}.
+ */
+@Deprecated
 public class MasterService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(MasterService.class);
 
@@ -102,6 +110,10 @@ public class MasterService extends AbstractLifecycleComponent {
         Setting.Property.NodeScope
     );
 
+    static final String CLUSTER_MANAGER_UPDATE_THREAD_NAME = "clusterManagerService#updateTask";
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #CLUSTER_MANAGER_UPDATE_THREAD_NAME} */
+    @Deprecated
     static final String MASTER_UPDATE_THREAD_NAME = "masterService#updateTask";
 
     ClusterStatePublisher clusterStatePublisher;
@@ -116,6 +128,8 @@ public class MasterService extends AbstractLifecycleComponent {
 
     private volatile PrioritizedOpenSearchThreadPoolExecutor threadPoolExecutor;
     private volatile Batcher taskBatcher;
+    protected final ClusterManagerTaskThrottler clusterManagerTaskThrottler;
+    private final ClusterManagerThrottlingStats throttlingStats;
 
     public MasterService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
         this.nodeName = Objects.requireNonNull(Node.NODE_NAME_SETTING.get(settings));
@@ -126,6 +140,13 @@ public MasterService(Settings settings, ClusterSettings clusterSettings, ThreadP
             this::setSlowTaskLoggingThreshold
         );
 
+        this.throttlingStats = new ClusterManagerThrottlingStats();
+        this.clusterManagerTaskThrottler = new ClusterManagerTaskThrottler(
+            settings,
+            clusterSettings,
+            this::getMinNodeVersion,
+            throttlingStats
+        );
         this.threadPool = threadPool;
     }
 
@@ -146,13 +167,13 @@ protected synchronized void doStart() {
         Objects.requireNonNull(clusterStatePublisher, "please set a cluster state publisher before starting");
         Objects.requireNonNull(clusterStateSupplier, "please set a cluster state supplier before starting");
         threadPoolExecutor = createThreadPoolExecutor();
-        taskBatcher = new Batcher(logger, threadPoolExecutor);
+        taskBatcher = new Batcher(logger, threadPoolExecutor, clusterManagerTaskThrottler);
     }
 
     protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
         return OpenSearchExecutors.newSinglePrioritizing(
-            nodeName + "/" + MASTER_UPDATE_THREAD_NAME,
-            daemonThreadFactory(nodeName, MASTER_UPDATE_THREAD_NAME),
+            nodeName + "/" + CLUSTER_MANAGER_UPDATE_THREAD_NAME,
+            daemonThreadFactory(nodeName, CLUSTER_MANAGER_UPDATE_THREAD_NAME),
             threadPool.getThreadContext(),
             threadPool.scheduler()
         );
@@ -161,8 +182,8 @@ protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
     @SuppressWarnings("unchecked")
     class Batcher extends TaskBatcher {
 
-        Batcher(Logger logger, PrioritizedOpenSearchThreadPoolExecutor threadExecutor) {
-            super(logger, threadExecutor);
+        Batcher(Logger logger, PrioritizedOpenSearchThreadPoolExecutor threadExecutor, TaskBatcherListener taskBatcherListener) {
+            super(logger, threadExecutor, taskBatcherListener);
         }
 
         @Override
@@ -223,48 +244,61 @@ ClusterState state() {
         return clusterStateSupplier.get();
     }
 
-    private static boolean isMasterUpdateThread() {
-        return Thread.currentThread().getName().contains(MASTER_UPDATE_THREAD_NAME);
+    private static boolean isClusterManagerUpdateThread() {
+        return Thread.currentThread().getName().contains(CLUSTER_MANAGER_UPDATE_THREAD_NAME)
+            || Thread.currentThread().getName().contains(MASTER_UPDATE_THREAD_NAME);
     }
 
-    public static boolean assertMasterUpdateThread() {
-        assert isMasterUpdateThread() : "not called from the master service thread";
+    public static boolean assertClusterManagerUpdateThread() {
+        assert isClusterManagerUpdateThread() : "not called from the cluster-manager service thread";
         return true;
     }
 
-    public static boolean assertNotMasterUpdateThread(String reason) {
-        assert isMasterUpdateThread() == false : "Expected current thread ["
+    public static boolean assertNotClusterManagerUpdateThread(String reason) {
+        assert isClusterManagerUpdateThread() == false : "Expected current thread ["
             + Thread.currentThread()
-            + "] to not be the master service thread. Reason: ["
+            + "] to not be the cluster-manager service thread. Reason: ["
             + reason
             + "]";
         return true;
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #assertClusterManagerUpdateThread()} */
+    @Deprecated
+    public static boolean assertMasterUpdateThread() {
+        return assertClusterManagerUpdateThread();
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #assertNotClusterManagerUpdateThread(String)} */
+    @Deprecated
+    public static boolean assertNotMasterUpdateThread(String reason) {
+        return assertNotClusterManagerUpdateThread(reason);
+    }
+
     private void runTasks(TaskInputs taskInputs) {
         final String summary = taskInputs.summary;
         if (!lifecycle.started()) {
-            logger.debug("processing [{}]: ignoring, master service not started", summary);
+            logger.debug("processing [{}]: ignoring, cluster-manager service not started", summary);
             return;
         }
 
         logger.debug("executing cluster state update for [{}]", summary);
         final ClusterState previousClusterState = state();
 
-        if (!previousClusterState.nodes().isLocalNodeElectedMaster() && taskInputs.runOnlyWhenMaster()) {
-            logger.debug("failing [{}]: local node is no longer master", summary);
-            taskInputs.onNoLongerMaster();
+        if (!previousClusterState.nodes().isLocalNodeElectedClusterManager() && taskInputs.runOnlyWhenClusterManager()) {
+            logger.debug("failing [{}]: local node is no longer cluster-manager", summary);
+            taskInputs.onNoLongerClusterManager();
             return;
         }
 
-        final long computationStartTime = threadPool.relativeTimeInMillis();
+        final long computationStartTime = threadPool.preciseRelativeTimeInNanos();
         final TaskOutputs taskOutputs = calculateTaskOutputs(taskInputs, previousClusterState);
         taskOutputs.notifyFailedTasks();
         final TimeValue computationTime = getTimeSince(computationStartTime);
         logExecutionTime(computationTime, "compute cluster state update", summary);
 
         if (taskOutputs.clusterStateUnchanged()) {
-            final long notificationStartTime = threadPool.relativeTimeInMillis();
+            final long notificationStartTime = threadPool.preciseRelativeTimeInNanos();
             taskOutputs.notifySuccessfulTasksOnUnchangedClusterState();
             final TimeValue executionTime = getTimeSince(notificationStartTime);
             logExecutionTime(executionTime, "notify listeners on unchanged cluster state", summary);
@@ -275,7 +309,7 @@ private void runTasks(TaskInputs taskInputs) {
             } else {
                 logger.debug("cluster state updated, version [{}], source [{}]", newClusterState.version(), summary);
             }
-            final long publicationStartTime = threadPool.relativeTimeInMillis();
+            final long publicationStartTime = threadPool.preciseRelativeTimeInNanos();
             try {
                 ClusterChangedEvent clusterChangedEvent = new ClusterChangedEvent(summary, newClusterState, previousClusterState);
                 // new cluster state, notify all listeners
@@ -301,15 +335,15 @@ private void runTasks(TaskInputs taskInputs) {
         }
     }
 
-    private TimeValue getTimeSince(long startTimeMillis) {
-        return TimeValue.timeValueMillis(Math.max(0, threadPool.relativeTimeInMillis() - startTimeMillis));
+    private TimeValue getTimeSince(long startTimeNanos) {
+        return TimeValue.timeValueMillis(TimeValue.nsecToMSec(threadPool.preciseRelativeTimeInNanos() - startTimeNanos));
     }
 
     protected void publish(ClusterChangedEvent clusterChangedEvent, TaskOutputs taskOutputs, long startTimeMillis) {
         final PlainActionFuture<Void> fut = new PlainActionFuture<Void>() {
             @Override
             protected boolean blockingAllowed() {
-                return isMasterUpdateThread() || super.blockingAllowed();
+                return isClusterManagerUpdateThread() || super.blockingAllowed();
             }
         };
         clusterStatePublisher.publish(clusterChangedEvent, fut, taskOutputs.createAckListener(threadPool, clusterChangedEvent.state()));
@@ -324,7 +358,7 @@ protected boolean blockingAllowed() {
     }
 
     void onPublicationSuccess(ClusterChangedEvent clusterChangedEvent, TaskOutputs taskOutputs) {
-        final long notificationStartTime = threadPool.relativeTimeInMillis();
+        final long notificationStartTime = threadPool.preciseRelativeTimeInNanos();
         taskOutputs.processedDifferentClusterState(clusterChangedEvent.previousState(), clusterChangedEvent.state());
 
         try {
@@ -402,7 +436,7 @@ private ClusterState patchVersions(ClusterState previousClusterState, ClusterTas
         ClusterState newClusterState = executionResult.resultingState;
 
         if (previousClusterState != newClusterState) {
-            // only the master controls the version numbers
+            // only the cluster-manager controls the version numbers
             Builder builder = incrementVersion(newClusterState);
             if (previousClusterState.routingTable() != newClusterState.routingTable()) {
                 builder.routingTable(
@@ -565,6 +599,27 @@ public List<PendingClusterTask> pendingTasks() {
         }).collect(Collectors.toList());
     }
 
+    /**
+     * Returns the number of throttled pending tasks.
+     */
+    public long numberOfThrottledPendingTasks() {
+        return throttlingStats.getTotalThrottledTaskCount();
+    }
+
+    /**
+     * Returns the stats of throttled pending tasks.
+     */
+    public ClusterManagerThrottlingStats getThrottlingStats() {
+        return throttlingStats;
+    }
+
+    /**
+     * Returns the min version of nodes in cluster
+     */
+    public Version getMinNodeVersion() {
+        return state().getNodes().getMinNodeVersion();
+    }
+
     /**
      * Returns the number of currently pending tasks.
      */
@@ -611,12 +666,15 @@ public void onFailure(String source, Exception e) {
         }
 
         @Override
-        public void onNoLongerMaster(String source) {
+        public void onNoLongerClusterManager(String source) {
             try (ThreadContext.StoredContext ignore = context.get()) {
-                listener.onNoLongerMaster(source);
+                listener.onNoLongerClusterManager(source);
             } catch (Exception e) {
                 logger.error(
-                    () -> new ParameterizedMessage("exception thrown by listener while notifying no longer master from [{}]", source),
+                    () -> new ParameterizedMessage(
+                        "exception thrown by listener while notifying no longer cluster-manager from [{}]",
+                        source
+                    ),
                     e
                 );
             }
@@ -722,7 +780,7 @@ private static class AckCountDownListener implements Discovery.AckListener {
 
         private final AckedClusterStateTaskListener ackedTaskListener;
         private final CountDown countDown;
-        private final DiscoveryNode masterNode;
+        private final DiscoveryNode clusterManagerNode;
         private final ThreadPool threadPool;
         private final long clusterStateVersion;
         private volatile Scheduler.Cancellable ackTimeoutCallback;
@@ -737,11 +795,11 @@ private static class AckCountDownListener implements Discovery.AckListener {
             this.ackedTaskListener = ackedTaskListener;
             this.clusterStateVersion = clusterStateVersion;
             this.threadPool = threadPool;
-            this.masterNode = nodes.getMasterNode();
+            this.clusterManagerNode = nodes.getClusterManagerNode();
             int countDown = 0;
             for (DiscoveryNode node : nodes) {
-                // we always wait for at least the master node
-                if (node.equals(masterNode) || ackedTaskListener.mustAck(node)) {
+                // we always wait for at least the cluster-manager node
+                if (node.equals(clusterManagerNode) || ackedTaskListener.mustAck(node)) {
                     countDown++;
                 }
             }
@@ -771,7 +829,7 @@ public void onCommit(TimeValue commitTime) {
 
         @Override
         public void onNodeAck(DiscoveryNode node, @Nullable Exception e) {
-            if (node.equals(masterNode) == false && ackedTaskListener.mustAck(node) == false) {
+            if (node.equals(clusterManagerNode) == false && ackedTaskListener.mustAck(node) == false) {
                 return;
             }
             if (e == null) {
@@ -815,9 +873,9 @@ private ClusterTasksResult<Object> executeTasks(TaskInputs taskInputs, ClusterSt
             List<Object> inputs = taskInputs.updateTasks.stream().map(tUpdateTask -> tUpdateTask.task).collect(Collectors.toList());
             clusterTasksResult = taskInputs.executor.execute(previousClusterState, inputs);
             if (previousClusterState != clusterTasksResult.resultingState
-                && previousClusterState.nodes().isLocalNodeElectedMaster()
-                && (clusterTasksResult.resultingState.nodes().isLocalNodeElectedMaster() == false)) {
-                throw new AssertionError("update task submitted to MasterService cannot remove master");
+                && previousClusterState.nodes().isLocalNodeElectedClusterManager()
+                && (clusterTasksResult.resultingState.nodes().isLocalNodeElectedClusterManager() == false)) {
+                throw new AssertionError("update task submitted to ClusterManagerService cannot remove cluster-manager");
             }
         } catch (Exception e) {
             logger.trace(
@@ -847,11 +905,9 @@ private ClusterTasksResult<Object> executeTasks(TaskInputs taskInputs, ClusterSt
         );
         if (Assertions.ENABLED) {
             ClusterTasksResult<Object> finalClusterTasksResult = clusterTasksResult;
-            taskInputs.updateTasks.forEach(
-                updateTask -> {
-                    assert finalClusterTasksResult.executionResults.containsKey(updateTask.task) : "missing task result for " + updateTask;
-                }
-            );
+            taskInputs.updateTasks.forEach(updateTask -> {
+                assert finalClusterTasksResult.executionResults.containsKey(updateTask.task) : "missing task result for " + updateTask;
+            });
         }
 
         return clusterTasksResult;
@@ -879,15 +935,26 @@ private class TaskInputs {
             this.updateTasks = updateTasks;
         }
 
-        boolean runOnlyWhenMaster() {
-            return executor.runOnlyOnMaster();
+        boolean runOnlyWhenClusterManager() {
+            return executor.runOnlyOnClusterManager();
         }
 
-        void onNoLongerMaster() {
-            updateTasks.forEach(task -> task.listener.onNoLongerMaster(task.source()));
+        void onNoLongerClusterManager() {
+            updateTasks.forEach(task -> task.listener.onNoLongerClusterManager(task.source()));
         }
     }
 
+    /**
+     * Functionality for register task key to cluster manager node.
+     *
+     * @param taskKey - task key of task
+     * @param throttlingEnabled - throttling is enabled for task or not i.e does data node perform retries on it or not
+     * @return throttling task key which needs to be passed while submitting task to cluster manager
+     */
+    public ClusterManagerTaskThrottler.ThrottlingKey registerClusterManagerTask(String taskKey, boolean throttlingEnabled) {
+        return clusterManagerTaskThrottler.registerClusterManagerTask(taskKey, throttlingEnabled);
+    }
+
     /**
      * Submits a batch of cluster state update tasks; submitted updates are guaranteed to be processed together,
      * potentially with more tasks of the same executor.
diff --git a/server/src/main/java/org/opensearch/cluster/service/PendingClusterTask.java b/server/src/main/java/org/opensearch/cluster/service/PendingClusterTask.java
index 18537b5ca18cc..b1723cca518fd 100644
--- a/server/src/main/java/org/opensearch/cluster/service/PendingClusterTask.java
+++ b/server/src/main/java/org/opensearch/cluster/service/PendingClusterTask.java
@@ -33,14 +33,19 @@
 package org.opensearch.cluster.service;
 
 import org.opensearch.common.Priority;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
 
 import java.io.IOException;
 
+/**
+ * Represents a task that is pending in the cluster
+ *
+ * @opensearch.internal
+ */
 public class PendingClusterTask implements Writeable {
 
     private long insertOrder;
diff --git a/server/src/main/java/org/opensearch/cluster/service/SourcePrioritizedRunnable.java b/server/src/main/java/org/opensearch/cluster/service/SourcePrioritizedRunnable.java
index 6532a14e9b289..073c66f2af435 100644
--- a/server/src/main/java/org/opensearch/cluster/service/SourcePrioritizedRunnable.java
+++ b/server/src/main/java/org/opensearch/cluster/service/SourcePrioritizedRunnable.java
@@ -37,6 +37,8 @@
 
 /**
  * PrioritizedRunnable that also has a source string
+ *
+ * @opensearch.internal
  */
 public abstract class SourcePrioritizedRunnable extends PrioritizedRunnable {
     protected final String source;
diff --git a/server/src/main/java/org/opensearch/cluster/service/TaskBatcher.java b/server/src/main/java/org/opensearch/cluster/service/TaskBatcher.java
index a0648e0d9ab12..5e58f495a16fb 100644
--- a/server/src/main/java/org/opensearch/cluster/service/TaskBatcher.java
+++ b/server/src/main/java/org/opensearch/cluster/service/TaskBatcher.java
@@ -36,8 +36,8 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -46,6 +46,7 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -53,17 +54,22 @@
 /**
  * Batching support for {@link PrioritizedOpenSearchThreadPoolExecutor}
  * Tasks that share the same batching key are batched (see {@link BatchedTask#batchingKey})
+ *
+ * @opensearch.internal
  */
 public abstract class TaskBatcher {
 
     private final Logger logger;
     private final PrioritizedOpenSearchThreadPoolExecutor threadExecutor;
     // package visible for tests
-    final Map<Object, LinkedHashSet<BatchedTask>> tasksPerBatchingKey = new HashMap<>();
+    final Map<Object, LinkedHashSet<BatchedTask>> tasksPerBatchingKey = new ConcurrentHashMap<>();
+    final Map<Object, Map<Object, BatchedTask>> taskIdentityPerBatchingKey = new ConcurrentHashMap<>();
+    private final TaskBatcherListener taskBatcherListener;
 
-    public TaskBatcher(Logger logger, PrioritizedOpenSearchThreadPoolExecutor threadExecutor) {
+    public TaskBatcher(Logger logger, PrioritizedOpenSearchThreadPoolExecutor threadExecutor, TaskBatcherListener taskBatcherListener) {
         this.logger = logger;
         this.threadExecutor = threadExecutor;
+        this.taskBatcherListener = taskBatcherListener;
     }
 
     public void submitTasks(List<? extends BatchedTask> tasks, @Nullable TimeValue timeout) throws OpenSearchRejectedExecutionException {
@@ -73,36 +79,48 @@ public void submitTasks(List<? extends BatchedTask> tasks, @Nullable TimeValue t
         final BatchedTask firstTask = tasks.get(0);
         assert tasks.stream().allMatch(t -> t.batchingKey == firstTask.batchingKey)
             : "tasks submitted in a batch should share the same batching key: " + tasks;
-        // convert to an identity map to check for dups based on task identity
-        final Map<Object, BatchedTask> tasksIdentity = tasks.stream()
-            .collect(
-                Collectors.toMap(
-                    BatchedTask::getTask,
-                    Function.identity(),
-                    (a, b) -> { throw new IllegalStateException("cannot add duplicate task: " + a); },
-                    IdentityHashMap::new
-                )
-            );
-
-        synchronized (tasksPerBatchingKey) {
-            LinkedHashSet<BatchedTask> existingTasks = tasksPerBatchingKey.computeIfAbsent(
-                firstTask.batchingKey,
-                k -> new LinkedHashSet<>(tasks.size())
-            );
-            for (BatchedTask existing : existingTasks) {
-                // check that there won't be two tasks with the same identity for the same batching key
-                BatchedTask duplicateTask = tasksIdentity.get(existing.getTask());
-                if (duplicateTask != null) {
-                    throw new IllegalStateException(
-                        "task ["
-                            + duplicateTask.describeTasks(Collections.singletonList(existing))
-                            + "] with source ["
-                            + duplicateTask.source
-                            + "] is already queued"
-                    );
+        assert tasks.stream().allMatch(t -> t.getTask().getClass() == firstTask.getTask().getClass())
+            : "tasks submitted in a batch should be of same class: " + tasks;
+
+        taskBatcherListener.onBeginSubmit(tasks);
+
+        try {
+            // convert to an identity map to check for dups based on task identity
+            final Map<Object, BatchedTask> tasksIdentity = tasks.stream()
+                .collect(Collectors.toMap(BatchedTask::getTask, Function.identity(), (a, b) -> {
+                    throw new IllegalStateException("cannot add duplicate task: " + a);
+                }, IdentityHashMap::new));
+            LinkedHashSet<BatchedTask> newTasks = new LinkedHashSet<>(tasks);
+            // Need to maintain below order in which task identity map and task map are updated.
+            // For insert: First insert identity in taskIdentity map with dup check and then insert task in taskMap.
+            // For remove: First remove task from taskMap and then remove identity from taskIdentity map.
+            // We are inserting identity first and removing at last to ensure no duplicate tasks are enqueued.
+            // Changing this order might lead to duplicate tasks in queue.
+            taskIdentityPerBatchingKey.merge(firstTask.batchingKey, tasksIdentity, (existingIdentities, newIdentities) -> {
+                for (Object newIdentity : newIdentities.keySet()) {
+                    // check that there won't be two tasks with the same identity for the same batching key
+                    if (existingIdentities.containsKey(newIdentity)) {
+                        BatchedTask duplicateTask = newIdentities.get(newIdentity);
+                        throw new IllegalStateException(
+                            "task ["
+                                + duplicateTask.describeTasks(Collections.singletonList(duplicateTask))
+                                + "] with source ["
+                                + duplicateTask.source
+                                + "] is already queued"
+                        );
+                    }
                 }
-            }
-            existingTasks.addAll(tasks);
+                existingIdentities.putAll(newIdentities);
+                return existingIdentities;
+            });
+            // since we have checked for dup tasks in above map, we can add all new task in map.
+            tasksPerBatchingKey.merge(firstTask.batchingKey, newTasks, (existingTasks, updatedTasks) -> {
+                existingTasks.addAll(updatedTasks);
+                return existingTasks;
+            });
+        } catch (Exception e) {
+            taskBatcherListener.onSubmitFailure(tasks);
+            throw e;
         }
 
         if (timeout != null) {
@@ -112,12 +130,14 @@ public void submitTasks(List<? extends BatchedTask> tasks, @Nullable TimeValue t
         }
     }
 
-    private void onTimeoutInternal(List<? extends BatchedTask> tasks, TimeValue timeout) {
+    void onTimeoutInternal(List<? extends BatchedTask> tasks, TimeValue timeout) {
         final ArrayList<BatchedTask> toRemove = new ArrayList<>();
+        final ArrayList<Object> toRemoveIdentities = new ArrayList<>();
         for (BatchedTask task : tasks) {
             if (task.processed.getAndSet(true) == false) {
                 logger.debug("task [{}] timed out after [{}]", task.source, timeout);
                 toRemove.add(task);
+                toRemoveIdentities.add(task.getTask());
             }
         }
         if (toRemove.isEmpty() == false) {
@@ -125,15 +145,23 @@ private void onTimeoutInternal(List<? extends BatchedTask> tasks, TimeValue time
             Object batchingKey = firstTask.batchingKey;
             assert tasks.stream().allMatch(t -> t.batchingKey == batchingKey)
                 : "tasks submitted in a batch should share the same batching key: " + tasks;
-            synchronized (tasksPerBatchingKey) {
-                LinkedHashSet<BatchedTask> existingTasks = tasksPerBatchingKey.get(batchingKey);
-                if (existingTasks != null) {
-                    existingTasks.removeAll(toRemove);
-                    if (existingTasks.isEmpty()) {
-                        tasksPerBatchingKey.remove(batchingKey);
-                    }
+            // While removing task, need to remove task first from taskMap and then remove identity from identityMap.
+            // Changing this order might lead to duplicate task during submission.
+            tasksPerBatchingKey.computeIfPresent(batchingKey, (tasksKey, existingTasks) -> {
+                existingTasks.removeAll(toRemove);
+                if (existingTasks.isEmpty()) {
+                    return null;
                 }
-            }
+                return existingTasks;
+            });
+            taskIdentityPerBatchingKey.computeIfPresent(batchingKey, (tasksKey, existingIdentities) -> {
+                toRemoveIdentities.stream().forEach(existingIdentities::remove);
+                if (existingIdentities.isEmpty()) {
+                    return null;
+                }
+                return existingIdentities;
+            });
+            taskBatcherListener.onTimeout(toRemove);
             onTimeout(toRemove, timeout);
         }
     }
@@ -150,17 +178,18 @@ void runIfNotProcessed(BatchedTask updateTask) {
         if (updateTask.processed.get() == false) {
             final List<BatchedTask> toExecute = new ArrayList<>();
             final Map<String, List<BatchedTask>> processTasksBySource = new HashMap<>();
-            synchronized (tasksPerBatchingKey) {
-                LinkedHashSet<BatchedTask> pending = tasksPerBatchingKey.remove(updateTask.batchingKey);
-                if (pending != null) {
-                    for (BatchedTask task : pending) {
-                        if (task.processed.getAndSet(true) == false) {
-                            logger.trace("will process {}", task);
-                            toExecute.add(task);
-                            processTasksBySource.computeIfAbsent(task.source, s -> new ArrayList<>()).add(task);
-                        } else {
-                            logger.trace("skipping {}, already processed", task);
-                        }
+            // While removing task, need to remove task first from taskMap and then remove identity from identityMap.
+            // Changing this order might lead to duplicate task during submission.
+            LinkedHashSet<BatchedTask> pending = tasksPerBatchingKey.remove(updateTask.batchingKey);
+            taskIdentityPerBatchingKey.remove(updateTask.batchingKey);
+            if (pending != null) {
+                for (BatchedTask task : pending) {
+                    if (task.processed.getAndSet(true) == false) {
+                        logger.trace("will process {}", task);
+                        toExecute.add(task);
+                        processTasksBySource.computeIfAbsent(task.source, s -> new ArrayList<>()).add(task);
+                    } else {
+                        logger.trace("skipping {}, already processed", task);
                     }
                 }
             }
@@ -171,6 +200,7 @@ void runIfNotProcessed(BatchedTask updateTask) {
                     return tasks.isEmpty() ? entry.getKey() : entry.getKey() + "[" + tasks + "]";
                 }).reduce((s1, s2) -> s1 + ", " + s2).orElse("");
 
+                taskBatcherListener.onBeginProcessing(toExecute);
                 run(updateTask.batchingKey, toExecute, tasksSummary);
             }
         }
diff --git a/server/src/main/java/org/opensearch/cluster/service/TaskBatcherListener.java b/server/src/main/java/org/opensearch/cluster/service/TaskBatcherListener.java
new file mode 100644
index 0000000000000..2feaf2540a96e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/TaskBatcherListener.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import java.util.List;
+
+/**
+ * Listener class for callback on various events of TaskBatcher.
+ */
+public interface TaskBatcherListener {
+    /**
+     * Callback called before submitting tasks.
+     * @param tasks list of tasks which will be submitted.
+     */
+    void onBeginSubmit(List<? extends TaskBatcher.BatchedTask> tasks);
+
+    /**
+     * Callback called if tasks submission due to any reason
+     * for e.g. failing due to duplicate tasks.
+     * @param tasks list of tasks which was failed to submit.
+     */
+    void onSubmitFailure(List<? extends TaskBatcher.BatchedTask> tasks);
+
+    /**
+     * Callback called before processing any tasks.
+     * @param tasks list of tasks which will be executed.
+     */
+    void onBeginProcessing(List<? extends TaskBatcher.BatchedTask> tasks);
+
+    /**
+     * Callback called when tasks are timed out.
+     * @param tasks list of tasks which will be executed.
+     */
+    void onTimeout(List<? extends TaskBatcher.BatchedTask> tasks);
+}
diff --git a/server/src/main/java/org/opensearch/cluster/service/package-info.java b/server/src/main/java/org/opensearch/cluster/service/package-info.java
new file mode 100644
index 0000000000000..57ff5731355b1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/cluster/service/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Cluster Service foundation classes. */
+package org.opensearch.cluster.service;
diff --git a/server/src/main/java/org/opensearch/common/AsyncBiFunction.java b/server/src/main/java/org/opensearch/common/AsyncBiFunction.java
index 916a0c09cf83d..575e357665964 100644
--- a/server/src/main/java/org/opensearch/common/AsyncBiFunction.java
+++ b/server/src/main/java/org/opensearch/common/AsyncBiFunction.java
@@ -31,10 +31,12 @@
 
 package org.opensearch.common;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * A {@link java.util.function.BiFunction}-like interface designed to be used with asynchronous executions.
+ *
+ * @opensearch.internal
  */
 public interface AsyncBiFunction<T, U, C> {
 
diff --git a/server/src/main/java/org/opensearch/common/FieldMemoryStats.java b/server/src/main/java/org/opensearch/common/FieldMemoryStats.java
index 8de38292e4cd0..86a2fe1397cec 100644
--- a/server/src/main/java/org/opensearch/common/FieldMemoryStats.java
+++ b/server/src/main/java/org/opensearch/common/FieldMemoryStats.java
@@ -32,60 +32,54 @@
 
 package org.opensearch.common;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
-import com.carrotsearch.hppc.cursors.ObjectLongCursor;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.Map;
 import java.util.Objects;
 
 /**
  * A reusable class to encode {@code field -&gt; memory size} mappings
+ *
+ * @opensearch.internal
  */
-public final class FieldMemoryStats implements Writeable, Iterable<ObjectLongCursor<String>> {
+public final class FieldMemoryStats implements Writeable, Iterable<Map.Entry<String, Long>> {
 
-    private final ObjectLongHashMap<String> stats;
+    private final Map<String, Long> stats;
 
     /**
      * Creates a new FieldMemoryStats instance
      */
-    public FieldMemoryStats(ObjectLongHashMap<String> stats) {
+    public FieldMemoryStats(Map<String, Long> stats) {
         this.stats = Objects.requireNonNull(stats, "status must be non-null");
-        assert !stats.containsKey(null);
+        assert stats.containsKey(null) == false;
     }
 
     /**
      * Creates a new FieldMemoryStats instance from a stream
      */
     public FieldMemoryStats(StreamInput input) throws IOException {
-        int size = input.readVInt();
-        stats = new ObjectLongHashMap<>(size);
-        for (int i = 0; i < size; i++) {
-            stats.put(input.readString(), input.readVLong());
-        }
+        stats = input.readMap(StreamInput::readString, StreamInput::readVLong);
     }
 
     /**
      * Adds / merges the given field memory stats into this stats instance
      */
     public void add(FieldMemoryStats fieldMemoryStats) {
-        for (ObjectLongCursor<String> entry : fieldMemoryStats.stats) {
-            stats.addTo(entry.key, entry.value);
+        for (final var entry : fieldMemoryStats.stats.entrySet()) {
+            stats.merge(entry.getKey(), entry.getValue(), Long::sum);
         }
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeVInt(stats.size());
-        for (ObjectLongCursor<String> entry : stats) {
-            out.writeString(entry.key);
-            out.writeVLong(entry.value);
-        }
+        out.writeMap(stats, StreamOutput::writeString, StreamOutput::writeVLong);
     }
 
     /**
@@ -97,9 +91,9 @@ public void writeTo(StreamOutput out) throws IOException {
      */
     public void toXContent(XContentBuilder builder, String key, String rawKey, String readableKey) throws IOException {
         builder.startObject(key);
-        for (ObjectLongCursor<String> entry : stats) {
-            builder.startObject(entry.key);
-            builder.humanReadableField(rawKey, readableKey, new ByteSizeValue(entry.value));
+        for (final var entry : stats.entrySet()) {
+            builder.startObject(entry.getKey());
+            builder.humanReadableField(rawKey, readableKey, new ByteSizeValue(entry.getValue()));
             builder.endObject();
         }
         builder.endObject();
@@ -109,7 +103,7 @@ public void toXContent(XContentBuilder builder, String key, String rawKey, Strin
      * Creates a deep copy of this stats instance
      */
     public FieldMemoryStats copy() {
-        return new FieldMemoryStats(stats.clone());
+        return new FieldMemoryStats(new HashMap<>(stats));
     }
 
     @Override
@@ -126,15 +120,15 @@ public int hashCode() {
     }
 
     @Override
-    public Iterator<ObjectLongCursor<String>> iterator() {
-        return stats.iterator();
+    public Iterator<Map.Entry<String, Long>> iterator() {
+        return stats.entrySet().iterator();
     }
 
     /**
      * Returns the fields value in bytes or <code>0</code> if it's not present in the stats
      */
     public long get(String field) {
-        return stats.get(field);
+        return stats.getOrDefault(field, 0L);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/LegacyTimeBasedUUIDGenerator.java b/server/src/main/java/org/opensearch/common/LegacyTimeBasedUUIDGenerator.java
deleted file mode 100644
index f9a7572afa2bf..0000000000000
--- a/server/src/main/java/org/opensearch/common/LegacyTimeBasedUUIDGenerator.java
+++ /dev/null
@@ -1,100 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common;
-
-import java.util.Base64;
-import java.util.concurrent.atomic.AtomicInteger;
-
-/**
- * These are essentially flake ids, but we use 6 (not 8) bytes for timestamp, and use 3 (not 2) bytes for sequence number.
- * For more information about flake ids, check out
- * https://archive.fo/2015.07.08-082503/http://www.boundary.com/blog/2012/01/flake-a-decentralized-k-ordered-unique-id-generator-in-erlang/
- */
-
-class LegacyTimeBasedUUIDGenerator implements UUIDGenerator {
-
-    // We only use bottom 3 bytes for the sequence number. Paranoia: init with random int so that if JVM/OS/machine goes down, clock slips
-    // backwards, and JVM comes back up, we are less likely to be on the same sequenceNumber at the same time:
-    private final AtomicInteger sequenceNumber = new AtomicInteger(SecureRandomHolder.INSTANCE.nextInt());
-
-    // Used to ensure clock moves forward:
-    private long lastTimestamp;
-
-    private static final byte[] SECURE_MUNGED_ADDRESS = MacAddressProvider.getSecureMungedAddress();
-
-    static {
-        assert SECURE_MUNGED_ADDRESS.length == 6;
-    }
-
-    /** Puts the lower numberOfLongBytes from l into the array, starting index pos. */
-    private static void putLong(byte[] array, long l, int pos, int numberOfLongBytes) {
-        for (int i = 0; i < numberOfLongBytes; ++i) {
-            array[pos + numberOfLongBytes - i - 1] = (byte) (l >>> (i * 8));
-        }
-    }
-
-    @Override
-    public String getBase64UUID() {
-        final int sequenceId = sequenceNumber.incrementAndGet() & 0xffffff;
-        long timestamp = System.currentTimeMillis();
-
-        synchronized (this) {
-            // Don't let timestamp go backwards, at least "on our watch" (while this JVM is running). We are still vulnerable if we are
-            // shut down, clock goes backwards, and we restart... for this we randomize the sequenceNumber on init to decrease chance of
-            // collision:
-            timestamp = Math.max(lastTimestamp, timestamp);
-
-            if (sequenceId == 0) {
-                // Always force the clock to increment whenever sequence number is 0, in case we have a long time-slip backwards:
-                timestamp++;
-            }
-
-            lastTimestamp = timestamp;
-        }
-
-        final byte[] uuidBytes = new byte[15];
-
-        // Only use lower 6 bytes of the timestamp (this will suffice beyond the year 10000):
-        putLong(uuidBytes, timestamp, 0, 6);
-
-        // MAC address adds 6 bytes:
-        System.arraycopy(SECURE_MUNGED_ADDRESS, 0, uuidBytes, 6, SECURE_MUNGED_ADDRESS.length);
-
-        // Sequence number adds 3 bytes:
-        putLong(uuidBytes, sequenceId, 12, 3);
-
-        assert 9 + SECURE_MUNGED_ADDRESS.length == uuidBytes.length;
-
-        return Base64.getUrlEncoder().withoutPadding().encodeToString(uuidBytes);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/Numbers.java b/server/src/main/java/org/opensearch/common/Numbers.java
deleted file mode 100644
index e2f5cdc0ab22d..0000000000000
--- a/server/src/main/java/org/opensearch/common/Numbers.java
+++ /dev/null
@@ -1,203 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common;
-
-import org.apache.lucene.util.BytesRef;
-
-import java.math.BigDecimal;
-import java.math.BigInteger;
-
-/**
- * A set of utilities for numbers.
- */
-public final class Numbers {
-
-    private static final BigInteger MAX_LONG_VALUE = BigInteger.valueOf(Long.MAX_VALUE);
-    private static final BigInteger MIN_LONG_VALUE = BigInteger.valueOf(Long.MIN_VALUE);
-
-    private Numbers() {}
-
-    public static long bytesToLong(BytesRef bytes) {
-        int high = (bytes.bytes[bytes.offset + 0] << 24) | ((bytes.bytes[bytes.offset + 1] & 0xff) << 16) | ((bytes.bytes[bytes.offset + 2]
-            & 0xff) << 8) | (bytes.bytes[bytes.offset + 3] & 0xff);
-        int low = (bytes.bytes[bytes.offset + 4] << 24) | ((bytes.bytes[bytes.offset + 5] & 0xff) << 16) | ((bytes.bytes[bytes.offset + 6]
-            & 0xff) << 8) | (bytes.bytes[bytes.offset + 7] & 0xff);
-        return (((long) high) << 32) | (low & 0x0ffffffffL);
-    }
-
-    public static byte[] intToBytes(int val) {
-        byte[] arr = new byte[4];
-        arr[0] = (byte) (val >>> 24);
-        arr[1] = (byte) (val >>> 16);
-        arr[2] = (byte) (val >>> 8);
-        arr[3] = (byte) (val);
-        return arr;
-    }
-
-    /**
-     * Converts an int to a byte array.
-     *
-     * @param val The int to convert to a byte array
-     * @return The byte array converted
-     */
-    public static byte[] shortToBytes(int val) {
-        byte[] arr = new byte[2];
-        arr[0] = (byte) (val >>> 8);
-        arr[1] = (byte) (val);
-        return arr;
-    }
-
-    /**
-     * Converts a long to a byte array.
-     *
-     * @param val The long to convert to a byte array
-     * @return The byte array converted
-     */
-    public static byte[] longToBytes(long val) {
-        byte[] arr = new byte[8];
-        arr[0] = (byte) (val >>> 56);
-        arr[1] = (byte) (val >>> 48);
-        arr[2] = (byte) (val >>> 40);
-        arr[3] = (byte) (val >>> 32);
-        arr[4] = (byte) (val >>> 24);
-        arr[5] = (byte) (val >>> 16);
-        arr[6] = (byte) (val >>> 8);
-        arr[7] = (byte) (val);
-        return arr;
-    }
-
-    /**
-     * Converts a double to a byte array.
-     *
-     * @param val The double to convert to a byte array
-     * @return The byte array converted
-     */
-    public static byte[] doubleToBytes(double val) {
-        return longToBytes(Double.doubleToRawLongBits(val));
-    }
-
-    /** Returns true if value is neither NaN nor infinite. */
-    public static boolean isValidDouble(double value) {
-        if (Double.isNaN(value) || Double.isInfinite(value)) {
-            return false;
-        }
-        return true;
-    }
-
-    /** Return the long that {@code n} stores, or throws an exception if the
-     *  stored value cannot be converted to a long that stores the exact same
-     *  value. */
-    public static long toLongExact(Number n) {
-        if (n instanceof Byte || n instanceof Short || n instanceof Integer || n instanceof Long) {
-            return n.longValue();
-        } else if (n instanceof Float || n instanceof Double) {
-            double d = n.doubleValue();
-            if (d != Math.round(d)) {
-                throw new IllegalArgumentException(n + " is not an integer value");
-            }
-            return n.longValue();
-        } else if (n instanceof BigDecimal) {
-            return ((BigDecimal) n).toBigIntegerExact().longValueExact();
-        } else if (n instanceof BigInteger) {
-            return ((BigInteger) n).longValueExact();
-        } else {
-            throw new IllegalArgumentException(
-                "Cannot check whether [" + n + "] of class [" + n.getClass().getName() + "] is actually a long"
-            );
-        }
-    }
-
-    // weak bounds on the BigDecimal representation to allow for coercion
-    private static BigDecimal BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE = BigDecimal.valueOf(Long.MAX_VALUE).add(BigDecimal.ONE);
-    private static BigDecimal BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE = BigDecimal.valueOf(Long.MIN_VALUE).subtract(BigDecimal.ONE);
-
-    /** Return the long that {@code stringValue} stores or throws an exception if the
-     *  stored value cannot be converted to a long that stores the exact same
-     *  value and {@code coerce} is false. */
-    public static long toLong(String stringValue, boolean coerce) {
-        try {
-            return Long.parseLong(stringValue);
-        } catch (NumberFormatException e) {
-            // we will try again with BigDecimal
-        }
-
-        final BigInteger bigIntegerValue;
-        try {
-            BigDecimal bigDecimalValue = new BigDecimal(stringValue);
-            if (bigDecimalValue.compareTo(BIGDECIMAL_GREATER_THAN_LONG_MAX_VALUE) >= 0
-                || bigDecimalValue.compareTo(BIGDECIMAL_LESS_THAN_LONG_MIN_VALUE) <= 0) {
-                throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
-            }
-            bigIntegerValue = coerce ? bigDecimalValue.toBigInteger() : bigDecimalValue.toBigIntegerExact();
-        } catch (ArithmeticException e) {
-            throw new IllegalArgumentException("Value [" + stringValue + "] has a decimal part");
-        } catch (NumberFormatException e) {
-            throw new IllegalArgumentException("For input string: \"" + stringValue + "\"");
-        }
-
-        if (bigIntegerValue.compareTo(MAX_LONG_VALUE) > 0 || bigIntegerValue.compareTo(MIN_LONG_VALUE) < 0) {
-            throw new IllegalArgumentException("Value [" + stringValue + "] is out of range for a long");
-        }
-
-        return bigIntegerValue.longValue();
-    }
-
-    /** Return the int that {@code n} stores, or throws an exception if the
-     *  stored value cannot be converted to an int that stores the exact same
-     *  value. */
-    public static int toIntExact(Number n) {
-        return Math.toIntExact(toLongExact(n));
-    }
-
-    /** Return the short that {@code n} stores, or throws an exception if the
-     *  stored value cannot be converted to a short that stores the exact same
-     *  value. */
-    public static short toShortExact(Number n) {
-        long l = toLongExact(n);
-        if (l != (short) l) {
-            throw new ArithmeticException("short overflow: " + l);
-        }
-        return (short) l;
-    }
-
-    /** Return the byte that {@code n} stores, or throws an exception if the
-     *  stored value cannot be converted to a byte that stores the exact same
-     *  value. */
-    public static byte toByteExact(Number n) {
-        long l = toLongExact(n);
-        if (l != (byte) l) {
-            throw new ArithmeticException("byte overflow: " + l);
-        }
-        return (byte) l;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/PidFile.java b/server/src/main/java/org/opensearch/common/PidFile.java
index ed3a3c1deb3c5..7033b63d38b6d 100644
--- a/server/src/main/java/org/opensearch/common/PidFile.java
+++ b/server/src/main/java/org/opensearch/common/PidFile.java
@@ -44,6 +44,8 @@
 /**
  * Process ID file abstraction that writes the current pid into a file and optionally
  * removes it on system exit.
+ *
+ * @opensearch.internal
  */
 public final class PidFile {
 
diff --git a/server/src/main/java/org/opensearch/common/Priority.java b/server/src/main/java/org/opensearch/common/Priority.java
index 908e19057e2ca..09a751362c945 100644
--- a/server/src/main/java/org/opensearch/common/Priority.java
+++ b/server/src/main/java/org/opensearch/common/Priority.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.common;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Priority levels.
+ *
+ * @opensearch.internal
+ */
 public enum Priority {
 
     IMMEDIATE((byte) 0),
diff --git a/server/src/main/java/org/opensearch/common/Randomness.java b/server/src/main/java/org/opensearch/common/Randomness.java
index 419a85cd973c4..2c60e848b9db9 100644
--- a/server/src/main/java/org/opensearch/common/Randomness.java
+++ b/server/src/main/java/org/opensearch/common/Randomness.java
@@ -56,6 +56,8 @@
  * process, non-reproducible sources of randomness are provided (unless
  * a setting is provided for a module that exposes a seed setting (e.g.,
  * NodeEnvironment#NODE_ID_SEED_SETTING)).
+ *
+ * @opensearch.internal
  */
 public final class Randomness {
     private static final Method currentMethod;
diff --git a/server/src/main/java/org/opensearch/common/Rounding.java b/server/src/main/java/org/opensearch/common/Rounding.java
index eb6737530a2b0..438822cb83725 100644
--- a/server/src/main/java/org/opensearch/common/Rounding.java
+++ b/server/src/main/java/org/opensearch/common/Rounding.java
@@ -38,11 +38,12 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.LocalTimeOffset.Gap;
 import org.opensearch.common.LocalTimeOffset.Overlap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.InternalApi;
 import org.opensearch.common.time.DateUtils;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -75,10 +76,17 @@
  * See <a href="https://davecturner.github.io/2019/04/14/timezone-rounding.html">this</a>
  * blog for some background reading. Its super interesting and the links are
  * a comedy gold mine. If you like time zones. Or hate them.
+ *
+ * @opensearch.internal
  */
 public abstract class Rounding implements Writeable {
     private static final Logger logger = LogManager.getLogger(Rounding.class);
 
+    /**
+     * A Date Time Unit
+     *
+     * @opensearch.internal
+     */
     public enum DateTimeUnit {
         WEEK_OF_WEEKYEAR((byte) 1, "week", IsoFields.WEEK_OF_WEEK_BASED_YEAR, true, TimeUnit.DAYS.toMillis(7)) {
             private final long extraLocalOffsetLookup = TimeUnit.DAYS.toMillis(7);
@@ -260,6 +268,8 @@ public void writeTo(StreamOutput out) throws IOException {
 
     /**
      * A strategy for rounding milliseconds since epoch.
+     *
+     * @opensearch.internal
      */
     public interface Prepared {
         /**
@@ -347,6 +357,11 @@ public static Builder builder(TimeValue interval) {
         return new Builder(interval);
     }
 
+    /**
+     * Builder for rounding
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final DateTimeUnit unit;
@@ -399,6 +414,21 @@ public Rounding build() {
     }
 
     private abstract class PreparedRounding implements Prepared {
+        /**
+         * The maximum limit up to which array-based prepared rounding is used.
+         * 128 is a power of two that isn't huge. We might be able to do
+         * better if the limit was based on the actual type of prepared
+         * rounding but this'll do for now.
+         */
+        private static final int DEFAULT_ARRAY_ROUNDING_MAX_THRESHOLD = 128;
+
+        /**
+         * The maximum limit up to which linear search is used, otherwise binary search is used.
+         * This is because linear search is much faster on small arrays.
+         * Benchmark results: <a href="https://github.com/opensearch-project/OpenSearch/pull/9727">PR #9727</a>
+         */
+        private static final int LINEAR_SEARCH_ARRAY_ROUNDING_MAX_THRESHOLD = 64;
+
         /**
          * Attempt to build a {@link Prepared} implementation that relies on pre-calcuated
          * "round down" points. If there would be more than {@code max} points then return
@@ -422,10 +452,17 @@ protected Prepared maybeUseArray(long minUtcMillis, long maxUtcMillis, int max)
                 values = ArrayUtil.grow(values, i + 1);
                 values[i++] = rounded;
             }
-            return new ArrayRounding(values, i, this);
+            return i <= LINEAR_SEARCH_ARRAY_ROUNDING_MAX_THRESHOLD
+                ? new BidirectionalLinearSearchArrayRounding(values, i, this)
+                : new BinarySearchArrayRounding(values, i, this);
         }
     }
 
+    /**
+     * Rounding time units
+     *
+     * @opensearch.internal
+     */
     static class TimeUnitRounding extends Rounding {
         static final byte ID = 1;
 
@@ -510,12 +547,11 @@ private LocalDateTime truncateLocalDateTime(LocalDateTime localDateTime) {
 
         @Override
         public Prepared prepare(long minUtcMillis, long maxUtcMillis) {
-            /*
-             * 128 is a power of two that isn't huge. We might be able to do
-             * better if the limit was based on the actual type of prepared
-             * rounding but this'll do for now.
-             */
-            return prepareOffsetOrJavaTimeRounding(minUtcMillis, maxUtcMillis).maybeUseArray(minUtcMillis, maxUtcMillis, 128);
+            return prepareOffsetOrJavaTimeRounding(minUtcMillis, maxUtcMillis).maybeUseArray(
+                minUtcMillis,
+                maxUtcMillis,
+                PreparedRounding.DEFAULT_ARRAY_ROUNDING_MAX_THRESHOLD
+            );
         }
 
         private TimeUnitPreparedRounding prepareOffsetOrJavaTimeRounding(long minUtcMillis, long maxUtcMillis) {
@@ -887,6 +923,11 @@ public final long nextRoundingValue(long utcMillis) {
         }
     }
 
+    /**
+     * Rounding time intervals
+     *
+     * @opensearch.internal
+     */
     static class TimeIntervalRounding extends Rounding {
         static final byte ID = 2;
 
@@ -1204,6 +1245,11 @@ public long nextRoundingValue(long utcMillis) {
         }
     }
 
+    /**
+     * Rounding offsets
+     *
+     * @opensearch.internal
+     */
     static class OffsetRounding extends Rounding {
         static final byte ID = 3;
 
@@ -1315,13 +1361,20 @@ public static Rounding read(StreamInput in) throws IOException {
 
     /**
      * Implementation of {@link Prepared} using pre-calculated "round down" points.
+     *
+     * <p>
+     * It uses binary search to find the greatest round-down point less than or equal to the given timestamp.
+     *
+     * @opensearch.internal
      */
-    private static class ArrayRounding implements Prepared {
+    @InternalApi
+    static class BinarySearchArrayRounding implements Prepared {
         private final long[] values;
         private final int max;
         private final Prepared delegate;
 
-        private ArrayRounding(long[] values, int max, Prepared delegate) {
+        BinarySearchArrayRounding(long[] values, int max, Prepared delegate) {
+            assert max > 0 : "at least one round-down point must be present";
             this.values = values;
             this.max = max;
             this.delegate = delegate;
@@ -1349,4 +1402,64 @@ public double roundingSize(long utcMillis, DateTimeUnit timeUnit) {
             return delegate.roundingSize(utcMillis, timeUnit);
         }
     }
+
+    /**
+     * Implementation of {@link Prepared} using pre-calculated "round down" points.
+     *
+     * <p>
+     * It uses linear search to find the greatest round-down point less than or equal to the given timestamp.
+     * For small inputs (&le; 64 elements), this can be much faster than binary search as it avoids the penalty of
+     * branch mispredictions and pipeline stalls, and accesses memory sequentially.
+     *
+     * <p>
+     * It uses "meet in the middle" linear search to avoid the worst case scenario when the desired element is present
+     * at either side of the array. This is helpful for time-series data where velocity increases over time, so more
+     * documents are likely to find a greater timestamp which is likely to be present on the right end of the array.
+     *
+     * @opensearch.internal
+     */
+    @InternalApi
+    static class BidirectionalLinearSearchArrayRounding implements Prepared {
+        private final long[] ascending;
+        private final long[] descending;
+        private final Prepared delegate;
+
+        BidirectionalLinearSearchArrayRounding(long[] values, int max, Prepared delegate) {
+            assert max > 0 : "at least one round-down point must be present";
+            this.delegate = delegate;
+            int len = (max + 1) >>> 1; // rounded-up to handle odd number of values
+            ascending = new long[len];
+            descending = new long[len];
+
+            for (int i = 0; i < len; i++) {
+                ascending[i] = values[i];
+                descending[i] = values[max - i - 1];
+            }
+        }
+
+        @Override
+        public long round(long utcMillis) {
+            int i = 0;
+            for (; i < ascending.length; i++) {
+                if (descending[i] <= utcMillis) {
+                    return descending[i];
+                }
+                if (ascending[i] > utcMillis) {
+                    assert i > 0 : "utcMillis must be after " + ascending[0];
+                    return ascending[i - 1];
+                }
+            }
+            return ascending[i - 1];
+        }
+
+        @Override
+        public long nextRoundingValue(long utcMillis) {
+            return delegate.nextRoundingValue(utcMillis);
+        }
+
+        @Override
+        public double roundingSize(long utcMillis, DateTimeUnit timeUnit) {
+            return delegate.roundingSize(utcMillis, timeUnit);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/StreamContext.java b/server/src/main/java/org/opensearch/common/StreamContext.java
new file mode 100644
index 0000000000000..b163ba65dc7db
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/StreamContext.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common;
+
+import org.opensearch.common.io.InputStreamContainer;
+
+import java.io.IOException;
+
+/**
+ * StreamContext is used to supply streams to vendor plugins using {@link StreamContext#provideStream}
+ *
+ * @opensearch.internal
+ */
+public class StreamContext {
+
+    private final CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException> streamSupplier;
+    private final long partSize;
+    private final long lastPartSize;
+    private final int numberOfParts;
+
+    /**
+     * Construct a new StreamProvider object
+     *
+     * @param streamSupplier A {@link CheckedTriFunction} that will be called with the <code>partNumber</code>, <code>partSize</code> and <code>position</code> in the stream
+     * @param partSize Size of all parts apart from the last one
+     * @param lastPartSize Size of the last part
+     * @param numberOfParts Total number of parts
+     */
+    public StreamContext(
+        CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException> streamSupplier,
+        long partSize,
+        long lastPartSize,
+        int numberOfParts
+    ) {
+        this.streamSupplier = streamSupplier;
+        this.partSize = partSize;
+        this.lastPartSize = lastPartSize;
+        this.numberOfParts = numberOfParts;
+    }
+
+    /**
+     * Copy constructor for overriding class
+     */
+    protected StreamContext(StreamContext streamContext) {
+        this.streamSupplier = streamContext.streamSupplier;
+        this.partSize = streamContext.partSize;
+        this.numberOfParts = streamContext.numberOfParts;
+        this.lastPartSize = streamContext.lastPartSize;
+    }
+
+    /**
+     * Vendor plugins can use this method to create new streams only when they are required for processing
+     * New streams won't be created till this method is called with the specific <code>partNumber</code>
+     *
+     * @param partNumber The index of the part
+     * @return A stream reference to the part requested
+     */
+    public InputStreamContainer provideStream(int partNumber) throws IOException {
+        long position = partSize * partNumber;
+        long size = (partNumber == numberOfParts - 1) ? lastPartSize : partSize;
+        return streamSupplier.apply(partNumber, size, position);
+    }
+
+    /**
+     * @return The number of parts in which this file is supposed to be uploaded
+     */
+    public int getNumberOfParts() {
+        return numberOfParts;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/StreamLimiter.java b/server/src/main/java/org/opensearch/common/StreamLimiter.java
new file mode 100644
index 0000000000000..ec203a1c30868
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/StreamLimiter.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common;
+
+import org.apache.lucene.store.RateLimiter;
+
+import java.io.IOException;
+import java.util.function.Supplier;
+
+/**
+ * The stream limiter that limits the transfer of bytes
+ *
+ * @opensearch.internal
+ */
+public class StreamLimiter {
+
+    private final Supplier<RateLimiter> rateLimiterSupplier;
+
+    private final StreamLimiter.Listener listener;
+
+    private int bytesSinceLastRateLimit;
+
+    public StreamLimiter(Supplier<RateLimiter> rateLimiterSupplier, Listener listener) {
+        this.rateLimiterSupplier = rateLimiterSupplier;
+        this.listener = listener;
+    }
+
+    public void maybePause(int bytes) throws IOException {
+        bytesSinceLastRateLimit += bytes;
+        final RateLimiter rateLimiter = rateLimiterSupplier.get();
+        if (rateLimiter != null) {
+            if (bytesSinceLastRateLimit >= rateLimiter.getMinPauseCheckBytes()) {
+                long pause = rateLimiter.pause(bytesSinceLastRateLimit);
+                bytesSinceLastRateLimit = 0;
+                if (pause > 0) {
+                    listener.onPause(pause);
+                }
+            }
+        }
+    }
+
+    /**
+     * Internal listener
+     *
+     * @opensearch.internal
+     */
+    public interface Listener {
+        void onPause(long nanos);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/Table.java b/server/src/main/java/org/opensearch/common/Table.java
index ff32faeb94edf..da14f628efa0f 100644
--- a/server/src/main/java/org/opensearch/common/Table.java
+++ b/server/src/main/java/org/opensearch/common/Table.java
@@ -33,6 +33,7 @@
 package org.opensearch.common;
 
 import org.opensearch.common.time.DateFormatter;
+import org.opensearch.core.common.Strings;
 
 import java.time.Instant;
 import java.time.ZoneOffset;
@@ -44,6 +45,11 @@
 
 import static java.util.Collections.emptyMap;
 
+/**
+ * A table.
+ *
+ * @opensearch.internal
+ */
 public class Table {
 
     private List<Cell> headers = new ArrayList<>();
@@ -224,6 +230,11 @@ public Map<String, String> getAliasMap() {
         return headerAliasMap;
     }
 
+    /**
+     * Cell in a table
+     *
+     * @opensearch.internal
+     */
     public static class Cell {
         public final Object value;
         public final Map<String, String> attr;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamBlobContainer.java
new file mode 100644
index 0000000000000..97f304d776f5c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamBlobContainer.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.core.action.ActionListener;
+
+import java.io.IOException;
+
+/**
+ * An extension of {@link BlobContainer} that adds {@link AsyncMultiStreamBlobContainer#asyncBlobUpload} to allow
+ * multipart uploads and performs integrity checks on transferred files
+ *
+ * @opensearch.internal
+ */
+public interface AsyncMultiStreamBlobContainer extends BlobContainer {
+
+    /**
+     * Reads blob content from multiple streams, each from a specific part of the file, which is provided by the
+     * StreamContextSupplier in the WriteContext passed to this method. An {@link IOException} is thrown if reading
+     * any of the input streams fails, or writing to the target blob fails
+     *
+     * @param writeContext         A WriteContext object encapsulating all information needed to perform the upload
+     * @param completionListener   Listener on which upload events should be published.
+     * @throws IOException if any of the input streams could not be read, or the target blob could not be written to
+     */
+    void asyncBlobUpload(WriteContext writeContext, ActionListener<Void> completionListener) throws IOException;
+
+    /**
+     * Creates an async callback of a {@link ReadContext} containing the multipart streams for a specified blob within the container.
+     * @param blobName The name of the blob for which the {@link ReadContext} needs to be fetched.
+     * @param listener  Async listener for {@link ReadContext} object which serves the input streams and other metadata for the blob
+     */
+    @ExperimentalApi
+    void readBlobAsync(String blobName, ActionListener<ReadContext> listener);
+
+    /*
+     * Wether underlying blobContainer can verify integrity of data after transfer. If true and if expected
+     * checksum is provided in WriteContext, then the checksum of transferred data is compared with expected checksum
+     * by underlying blobContainer. In this case, caller doesn't need to ensure integrity of data.
+     */
+    boolean remoteIntegrityCheckSupported();
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainer.java
new file mode 100644
index 0000000000000..82bc7a0baed50
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainer.java
@@ -0,0 +1,174 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.DecryptedRangedStreamProvider;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * EncryptedBlobContainer is an encrypted BlobContainer that is backed by a
+ * {@link AsyncMultiStreamBlobContainer}
+ *
+ * @opensearch.internal
+ */
+public class AsyncMultiStreamEncryptedBlobContainer<T, U> extends EncryptedBlobContainer<T, U> implements AsyncMultiStreamBlobContainer {
+
+    private final AsyncMultiStreamBlobContainer blobContainer;
+    private final CryptoHandler<T, U> cryptoHandler;
+
+    public AsyncMultiStreamEncryptedBlobContainer(AsyncMultiStreamBlobContainer blobContainer, CryptoHandler<T, U> cryptoHandler) {
+        super(blobContainer, cryptoHandler);
+        this.blobContainer = blobContainer;
+        this.cryptoHandler = cryptoHandler;
+    }
+
+    @Override
+    public void asyncBlobUpload(WriteContext writeContext, ActionListener<Void> completionListener) throws IOException {
+        EncryptedWriteContext<T, U> encryptedWriteContext = new EncryptedWriteContext<>(writeContext, cryptoHandler);
+        blobContainer.asyncBlobUpload(encryptedWriteContext, completionListener);
+    }
+
+    @Override
+    public void readBlobAsync(String blobName, ActionListener<ReadContext> listener) {
+        try {
+            final U cryptoContext = cryptoHandler.loadEncryptionMetadata(getEncryptedHeaderContentSupplier(blobName));
+            ActionListener<ReadContext> decryptingCompletionListener = ActionListener.map(
+                listener,
+                readContext -> new DecryptedReadContext<>(readContext, cryptoHandler, cryptoContext)
+            );
+
+            blobContainer.readBlobAsync(blobName, decryptingCompletionListener);
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
+    @Override
+    public boolean remoteIntegrityCheckSupported() {
+        return false;
+    }
+
+    static class EncryptedWriteContext<T, U> extends WriteContext {
+
+        private final T encryptionMetadata;
+        private final CryptoHandler<T, U> cryptoHandler;
+        private final long fileSize;
+
+        /**
+         * Construct a new encrypted WriteContext object
+         */
+        public EncryptedWriteContext(WriteContext writeContext, CryptoHandler<T, U> cryptoHandler) {
+            super(writeContext);
+            this.cryptoHandler = cryptoHandler;
+            this.encryptionMetadata = this.cryptoHandler.initEncryptionMetadata();
+            this.fileSize = this.cryptoHandler.estimateEncryptedLengthOfEntireContent(encryptionMetadata, writeContext.getFileSize());
+        }
+
+        public StreamContext getStreamProvider(long partSize) {
+            long adjustedPartSize = cryptoHandler.adjustContentSizeForPartialEncryption(encryptionMetadata, partSize);
+            StreamContext streamContext = super.getStreamProvider(adjustedPartSize);
+            return new EncryptedStreamContext<>(streamContext, cryptoHandler, encryptionMetadata);
+        }
+
+        /**
+         * @return The total size of the encrypted file
+         */
+        public long getFileSize() {
+            return fileSize;
+        }
+    }
+
+    static class EncryptedStreamContext<T, U> extends StreamContext {
+
+        private final CryptoHandler<T, U> cryptoHandler;
+        private final T encryptionMetadata;
+
+        /**
+         * Construct a new encrypted StreamContext object
+         */
+        public EncryptedStreamContext(StreamContext streamContext, CryptoHandler<T, U> cryptoHandler, T encryptionMetadata) {
+            super(streamContext);
+            this.cryptoHandler = cryptoHandler;
+            this.encryptionMetadata = encryptionMetadata;
+        }
+
+        @Override
+        public InputStreamContainer provideStream(int partNumber) throws IOException {
+            InputStreamContainer inputStreamContainer = super.provideStream(partNumber);
+            return cryptoHandler.createEncryptingStreamOfPart(encryptionMetadata, inputStreamContainer, getNumberOfParts(), partNumber);
+        }
+
+    }
+
+    /**
+     * DecryptedReadContext decrypts the encrypted {@link ReadContext} by acting as a transformation wrapper around
+     * the encrypted object
+     * @param <T> Encryption Metadata / CryptoContext for the {@link CryptoHandler} instance
+     * @param <U> Parsed Encryption Metadata / CryptoContext for the {@link CryptoHandler} instance
+     */
+    static class DecryptedReadContext<T, U> extends ReadContext {
+
+        private final CryptoHandler<T, U> cryptoHandler;
+        private final U cryptoContext;
+        private Long blobSize;
+
+        public DecryptedReadContext(ReadContext readContext, CryptoHandler<T, U> cryptoHandler, U cryptoContext) {
+            super(readContext);
+            this.cryptoHandler = cryptoHandler;
+            this.cryptoContext = cryptoContext;
+        }
+
+        @Override
+        public long getBlobSize() {
+            // initializes the value lazily
+            if (blobSize == null) {
+                this.blobSize = this.cryptoHandler.estimateDecryptedLength(cryptoContext, super.getBlobSize());
+            }
+            return this.blobSize;
+        }
+
+        @Override
+        public List<StreamPartCreator> getPartStreams() {
+            return super.getPartStreams().stream()
+                .map(supplier -> (StreamPartCreator) () -> supplier.get().thenApply(this::decryptInputStreamContainer))
+                .collect(Collectors.toUnmodifiableList());
+        }
+
+        /**
+         * Transforms an encrypted {@link InputStreamContainer} to a decrypted instance
+         * @param inputStreamContainer encrypted input stream container instance
+         * @return decrypted input stream container instance
+         */
+        private InputStreamContainer decryptInputStreamContainer(InputStreamContainer inputStreamContainer) {
+            long startOfStream = inputStreamContainer.getOffset();
+            long endOfStream = startOfStream + inputStreamContainer.getContentLength() - 1;
+            DecryptedRangedStreamProvider decryptedStreamProvider = cryptoHandler.createDecryptingStreamOfRange(
+                cryptoContext,
+                startOfStream,
+                endOfStream
+            );
+
+            long adjustedPos = decryptedStreamProvider.getAdjustedRange()[0];
+            long adjustedLength = decryptedStreamProvider.getAdjustedRange()[1] - adjustedPos + 1;
+            final InputStream decryptedStream = decryptedStreamProvider.getDecryptedStreamProvider()
+                .apply(inputStreamContainer.getInputStream());
+            return new InputStreamContainer(decryptedStream, adjustedLength, adjustedPos);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/BlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/BlobContainer.java
index bdc1d56759963..3cdb1ce30b68d 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/BlobContainer.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/BlobContainer.java
@@ -32,15 +32,21 @@
 
 package org.opensearch.common.blobstore;
 
+import org.opensearch.core.action.ActionListener;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.NoSuchFileException;
+import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
 /**
  * An interface for managing a repository of blob entries, where each blob entry is just a named group of bytes.
+ *
+ * @opensearch.internal
  */
 public interface BlobContainer {
 
@@ -189,4 +195,55 @@ default long readBlobPreferredLength() {
      * @throws  IOException if there were any failures in reading from the blob container.
      */
     Map<String, BlobMetadata> listBlobsByPrefix(String blobNamePrefix) throws IOException;
+
+    /**
+     * The type representing sort order of blob names
+     */
+    enum BlobNameSortOrder {
+
+        LEXICOGRAPHIC(Comparator.comparing(BlobMetadata::name));
+
+        final Comparator<BlobMetadata> comparator;
+
+        public Comparator<BlobMetadata> comparator() {
+            return comparator;
+        }
+
+        BlobNameSortOrder(final Comparator<BlobMetadata> comparator) {
+            this.comparator = comparator;
+        }
+    }
+
+    /**
+     * Lists all blobs in the container that match the specified prefix in lexicographic order
+     * @param blobNamePrefix The prefix to match against blob names in the container.
+     * @param limit Limits the result size to min(limit, number of keys)
+     * @param blobNameSortOrder Comparator to sort keys with
+     * @param listener the listener to be notified upon request completion
+     */
+    default void listBlobsByPrefixInSortedOrder(
+        String blobNamePrefix,
+        int limit,
+        BlobNameSortOrder blobNameSortOrder,
+        ActionListener<List<BlobMetadata>> listener
+    ) {
+        if (limit < 0) {
+            throw new IllegalArgumentException("limit should not be a negative value");
+        }
+        try {
+            listener.onResponse(listBlobsByPrefixInSortedOrder(blobNamePrefix, limit, blobNameSortOrder));
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
+    default List<BlobMetadata> listBlobsByPrefixInSortedOrder(String blobNamePrefix, int limit, BlobNameSortOrder blobNameSortOrder)
+        throws IOException {
+        if (limit < 0) {
+            throw new IllegalArgumentException("limit should not be a negative value");
+        }
+        List<BlobMetadata> blobNames = new ArrayList<>(listBlobsByPrefix(blobNamePrefix).values());
+        blobNames.sort(blobNameSortOrder.comparator());
+        return blobNames.subList(0, Math.min(blobNames.size(), limit));
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/blobstore/BlobMetadata.java b/server/src/main/java/org/opensearch/common/blobstore/BlobMetadata.java
index 52b103eaf79bb..37c70365b6a11 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/BlobMetadata.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/BlobMetadata.java
@@ -34,6 +34,8 @@
 
 /**
  * An interface for providing basic metadata about a blob.
+ *
+ * @opensearch.internal
  */
 public interface BlobMetadata {
 
diff --git a/server/src/main/java/org/opensearch/common/blobstore/BlobPath.java b/server/src/main/java/org/opensearch/common/blobstore/BlobPath.java
index 24aee647e7ac0..d5242fd5e7347 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/BlobPath.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/BlobPath.java
@@ -41,6 +41,8 @@
 
 /**
  * The list of paths where a blob can reside.  The contents of the paths are dependent upon the implementation of {@link BlobContainer}.
+ *
+ * @opensearch.internal
  */
 public class BlobPath implements Iterable<String> {
 
diff --git a/server/src/main/java/org/opensearch/common/blobstore/BlobStore.java b/server/src/main/java/org/opensearch/common/blobstore/BlobStore.java
index 42a347d378823..2ee3e9557b354 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/BlobStore.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/BlobStore.java
@@ -31,12 +31,16 @@
 
 package org.opensearch.common.blobstore;
 
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+
 import java.io.Closeable;
 import java.util.Collections;
 import java.util.Map;
 
 /**
  * An interface for storing blobs.
+ *
+ * @opensearch.internal
  */
 public interface BlobStore extends Closeable {
 
@@ -51,4 +55,9 @@ public interface BlobStore extends Closeable {
     default Map<String, Long> stats() {
         return Collections.emptyMap();
     }
+
+    /**
+     * Reload the blob store inplace
+     */
+    default void reload(RepositoryMetadata repositoryMetadata) {}
 }
diff --git a/server/src/main/java/org/opensearch/common/blobstore/BlobStoreException.java b/server/src/main/java/org/opensearch/common/blobstore/BlobStoreException.java
index a71a686dbd0d0..e60399db737b3 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/BlobStoreException.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/BlobStoreException.java
@@ -33,10 +33,15 @@
 package org.opensearch.common.blobstore;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown on blob store errors
+ *
+ * @opensearch.internal
+ */
 public class BlobStoreException extends OpenSearchException {
 
     public BlobStoreException(String msg) {
diff --git a/server/src/main/java/org/opensearch/common/blobstore/DeleteResult.java b/server/src/main/java/org/opensearch/common/blobstore/DeleteResult.java
index 1a6577cbbb21d..3b424c582ebc6 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/DeleteResult.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/DeleteResult.java
@@ -34,6 +34,8 @@
 
 /**
  * The result of deleting multiple blobs from a {@link BlobStore}.
+ *
+ * @opensearch.internal
  */
 public final class DeleteResult {
 
diff --git a/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobContainer.java
new file mode 100644
index 0000000000000..d0933741339d9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobContainer.java
@@ -0,0 +1,194 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.common.CheckedBiConsumer;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.DecryptedRangedStreamProvider;
+import org.opensearch.common.crypto.EncryptedHeaderContentSupplier;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * EncryptedBlobContainer is a wrapper around BlobContainer that encrypts the data on the fly.
+ */
+public class EncryptedBlobContainer<T, U> implements BlobContainer {
+
+    private final BlobContainer blobContainer;
+    private final CryptoHandler<T, U> cryptoHandler;
+
+    public EncryptedBlobContainer(BlobContainer blobContainer, CryptoHandler<T, U> cryptoHandler) {
+        this.blobContainer = blobContainer;
+        this.cryptoHandler = cryptoHandler;
+    }
+
+    @Override
+    public BlobPath path() {
+        return blobContainer.path();
+    }
+
+    @Override
+    public boolean blobExists(String blobName) throws IOException {
+        return blobContainer.blobExists(blobName);
+    }
+
+    @Override
+    public InputStream readBlob(String blobName) throws IOException {
+        InputStream inputStream = blobContainer.readBlob(blobName);
+        return cryptoHandler.createDecryptingStream(inputStream);
+    }
+
+    EncryptedHeaderContentSupplier getEncryptedHeaderContentSupplier(String blobName) {
+        return (start, end) -> {
+            byte[] buffer;
+            int length = (int) (end - start + 1);
+            try (InputStream inputStream = blobContainer.readBlob(blobName, start, length)) {
+                buffer = new byte[length];
+                inputStream.readNBytes(buffer, (int) start, buffer.length);
+            }
+            return buffer;
+        };
+    }
+
+    @Override
+    public InputStream readBlob(String blobName, long position, long length) throws IOException {
+        U encryptionMetadata = cryptoHandler.loadEncryptionMetadata(getEncryptedHeaderContentSupplier(blobName));
+        DecryptedRangedStreamProvider decryptedStreamProvider = cryptoHandler.createDecryptingStreamOfRange(
+            encryptionMetadata,
+            position,
+            position + length - 1
+        );
+        long adjustedPos = decryptedStreamProvider.getAdjustedRange()[0];
+        long adjustedLength = decryptedStreamProvider.getAdjustedRange()[1] - adjustedPos + 1;
+        InputStream encryptedStream = blobContainer.readBlob(blobName, adjustedPos, adjustedLength);
+        return decryptedStreamProvider.getDecryptedStreamProvider().apply(encryptedStream);
+    }
+
+    @Override
+    public long readBlobPreferredLength() {
+        return blobContainer.readBlobPreferredLength();
+    }
+
+    private void executeWrite(InputStream inputStream, long blobSize, CheckedBiConsumer<InputStream, Long, IOException> writeConsumer)
+        throws IOException {
+        T cryptoContext = cryptoHandler.initEncryptionMetadata();
+        InputStreamContainer streamContainer = new InputStreamContainer(inputStream, blobSize, 0);
+        InputStreamContainer encryptedStream = cryptoHandler.createEncryptingStream(cryptoContext, streamContainer);
+        long cryptoLength = cryptoHandler.estimateEncryptedLengthOfEntireContent(cryptoContext, blobSize);
+        writeConsumer.accept(encryptedStream.getInputStream(), cryptoLength);
+    }
+
+    @Override
+    public void writeBlob(String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists) throws IOException {
+        executeWrite(
+            inputStream,
+            blobSize,
+            (encryptedStream, encryptedLength) -> blobContainer.writeBlob(blobName, encryptedStream, encryptedLength, failIfAlreadyExists)
+        );
+    }
+
+    @Override
+    public void writeBlobAtomic(String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists) throws IOException {
+        executeWrite(
+            inputStream,
+            blobSize,
+            (encryptedStream, encryptedLength) -> blobContainer.writeBlobAtomic(
+                blobName,
+                encryptedStream,
+                encryptedLength,
+                failIfAlreadyExists
+            )
+        );
+    }
+
+    @Override
+    public DeleteResult delete() throws IOException {
+        return blobContainer.delete();
+    }
+
+    @Override
+    public void deleteBlobsIgnoringIfNotExists(List<String> blobNames) throws IOException {
+        blobContainer.deleteBlobsIgnoringIfNotExists(blobNames);
+    }
+
+    @Override
+    public Map<String, BlobMetadata> listBlobs() throws IOException {
+        Map<String, BlobMetadata> blobMetadataMap = blobContainer.listBlobs();
+        return convertToEncryptedMetadataMap(blobMetadataMap);
+    }
+
+    @Override
+    public Map<String, BlobContainer> children() throws IOException {
+        Map<String, BlobContainer> children = blobContainer.children();
+        if (children != null) {
+            return children.entrySet()
+                .stream()
+                .collect(Collectors.toMap(Map.Entry::getKey, entry -> new EncryptedBlobContainer<>(entry.getValue(), cryptoHandler)));
+        } else {
+            return null;
+        }
+    }
+
+    @Override
+    public Map<String, BlobMetadata> listBlobsByPrefix(String blobNamePrefix) throws IOException {
+        Map<String, BlobMetadata> blobMetadataMap = blobContainer.listBlobsByPrefix(blobNamePrefix);
+        return convertToEncryptedMetadataMap(blobMetadataMap);
+    }
+
+    private Map<String, BlobMetadata> convertToEncryptedMetadataMap(Map<String, BlobMetadata> blobMetadataMap) {
+        if (blobMetadataMap == null) {
+            return null;
+        }
+
+        return blobMetadataMap.entrySet()
+            .stream()
+            .collect(
+                Collectors.toMap(
+                    Map.Entry::getKey,
+                    entry -> new EncryptedBlobMetadata<>(entry.getValue(), cryptoHandler, getEncryptedHeaderContentSupplier(entry.getKey()))
+                )
+            );
+
+    }
+
+    @Override
+    public void listBlobsByPrefixInSortedOrder(
+        String blobNamePrefix,
+        int limit,
+        BlobNameSortOrder blobNameSortOrder,
+        ActionListener<List<BlobMetadata>> listener
+    ) {
+        ActionListener<List<BlobMetadata>> encryptedMetadataListener = ActionListener.delegateFailure(
+            listener,
+            (delegatedListener, metadataList) -> {
+                if (metadataList != null) {
+                    List<BlobMetadata> encryptedMetadata = metadataList.stream()
+                        .map(
+                            blobMetadata -> new EncryptedBlobMetadata<>(
+                                blobMetadata,
+                                cryptoHandler,
+                                getEncryptedHeaderContentSupplier(blobMetadata.name())
+                            )
+                        )
+                        .collect(Collectors.toList());
+                    delegatedListener.onResponse(encryptedMetadata);
+                } else {
+                    delegatedListener.onResponse(null);
+                }
+            }
+        );
+        blobContainer.listBlobsByPrefixInSortedOrder(blobNamePrefix, limit, blobNameSortOrder, encryptedMetadataListener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobMetadata.java b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobMetadata.java
new file mode 100644
index 0000000000000..8917bba806d08
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobMetadata.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.EncryptedHeaderContentSupplier;
+
+import java.io.IOException;
+
+/**
+ * Adjusts length of encrypted blob to raw length
+ */
+public class EncryptedBlobMetadata<T, U> implements BlobMetadata {
+    private final EncryptedHeaderContentSupplier encryptedHeaderContentSupplier;
+    private final BlobMetadata delegate;
+    private final CryptoHandler<T, U> cryptoHandler;
+
+    public EncryptedBlobMetadata(
+        BlobMetadata delegate,
+        CryptoHandler<T, U> cryptoHandler,
+        EncryptedHeaderContentSupplier encryptedHeaderContentSupplier
+    ) {
+        this.encryptedHeaderContentSupplier = encryptedHeaderContentSupplier;
+        this.delegate = delegate;
+        this.cryptoHandler = cryptoHandler;
+    }
+
+    @Override
+    public String name() {
+        return delegate.name();
+    }
+
+    @Override
+    public long length() {
+        U cryptoContext;
+        try {
+            cryptoContext = cryptoHandler.loadEncryptionMetadata(encryptedHeaderContentSupplier);
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+        return cryptoHandler.estimateDecryptedLength(cryptoContext, delegate.length());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobStore.java b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobStore.java
new file mode 100644
index 0000000000000..4d2d69e473438
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/EncryptedBlobStore.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.crypto.CryptoHandlerRegistry;
+import org.opensearch.crypto.CryptoRegistryException;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * The EncryptedBlobStore is a decorator class that wraps an existing BlobStore and provides encryption and decryption
+ * capabilities for the stored data. It uses a CryptoManager to handle encryption and decryption operations based on
+ * the provided CryptoMetadata. The EncryptedBlobStore ensures that all data written to and read from the underlying
+ * BlobStore is encrypted and decrypted transparently.
+ */
+public class EncryptedBlobStore implements BlobStore {
+
+    private final BlobStore blobStore;
+    private final CryptoHandler<?, ?> cryptoHandler;
+
+    /**
+     * Constructs an EncryptedBlobStore that wraps the provided BlobStore with encryption capabilities based on the
+     * given CryptoMetadata.
+     *
+     * @param blobStore     The underlying BlobStore to be wrapped and used for storing encrypted data.
+     * @param cryptoMetadata The CryptoMetadata containing information about the key provider and settings for encryption.
+     * @throws CryptoRegistryException If the CryptoManager is not found during encrypted BlobStore creation.
+     */
+    public EncryptedBlobStore(BlobStore blobStore, CryptoMetadata cryptoMetadata) {
+        CryptoHandlerRegistry cryptoHandlerRegistry = CryptoHandlerRegistry.getInstance();
+        assert cryptoHandlerRegistry != null : "CryptoManagerRegistry is not initialized";
+        this.cryptoHandler = cryptoHandlerRegistry.fetchCryptoHandler(cryptoMetadata);
+        if (cryptoHandler == null) {
+            throw new CryptoRegistryException(
+                cryptoMetadata.keyProviderName(),
+                cryptoMetadata.keyProviderType(),
+                "Crypto manager not found during encrypted blob store creation."
+            );
+        }
+        this.blobStore = blobStore;
+    }
+
+    /**
+     * Retrieves a BlobContainer from the underlying BlobStore based on the provided BlobPath. The returned BlobContainer
+     * is wrapped in an EncryptedBlobContainer to enable transparent encryption and decryption of data.
+     *
+     * @param path The BlobPath specifying the location of the BlobContainer.
+     * @return An EncryptedBlobContainer wrapping the BlobContainer retrieved from the underlying BlobStore.
+     */
+    @Override
+    public BlobContainer blobContainer(BlobPath path) {
+        BlobContainer blobContainer = blobStore.blobContainer(path);
+        if (blobContainer instanceof AsyncMultiStreamBlobContainer) {
+            return new AsyncMultiStreamEncryptedBlobContainer<>((AsyncMultiStreamBlobContainer) blobContainer, cryptoHandler);
+        }
+        return new EncryptedBlobContainer<>(blobContainer, cryptoHandler);
+    }
+
+    /**
+     * Retrieves statistics about the BlobStore. Delegates the call to the underlying BlobStore's stats() method.
+     *
+     * @return A map containing statistics about the BlobStore.
+     */
+    @Override
+    public Map<String, Long> stats() {
+        return blobStore.stats();
+    }
+
+    /**
+     * Closes the EncryptedBlobStore by decrementing the reference count of the CryptoManager and closing the
+     * underlying BlobStore. This ensures proper cleanup of resources.
+     *
+     * @throws IOException If an I/O error occurs while closing the BlobStore.
+     */
+    @Override
+    public void close() throws IOException {
+        cryptoHandler.close();
+        blobStore.close();
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/exception/CorruptFileException.java b/server/src/main/java/org/opensearch/common/blobstore/exception/CorruptFileException.java
new file mode 100644
index 0000000000000..e30f515b57495
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/exception/CorruptFileException.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.exception;
+
+import java.io.IOException;
+
+/**
+ * Exception thrown when remote integrity checks
+ *
+ * @opensearch.internal
+ */
+public class CorruptFileException extends IOException {
+
+    private final String fileName;
+
+    public CorruptFileException(String message, String fileName) {
+        super(message);
+        this.fileName = fileName;
+    }
+
+    public CorruptFileException(String message, Throwable cause, String fileName) {
+        super(message, cause);
+        this.fileName = fileName;
+    }
+
+    public CorruptFileException(Throwable cause, String fileName) {
+        super(cause);
+        this.fileName = fileName;
+    }
+
+    public String getFileName() {
+        return fileName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/exception/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/exception/package-info.java
new file mode 100644
index 0000000000000..5f042a9c0adc3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/exception/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Exceptions for blobstore abstractions */
+package org.opensearch.common.blobstore.exception;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobContainer.java
index 0fd20e6bb4990..394855671688a 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobContainer.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobContainer.java
@@ -40,7 +40,7 @@
 import org.opensearch.common.blobstore.support.AbstractBlobContainer;
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
 import org.opensearch.common.io.Streams;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -73,6 +73,8 @@
  * Note that the methods in this implementation of {@link org.opensearch.common.blobstore.BlobContainer} may
  * additionally throw a {@link java.lang.SecurityException} if the configured {@link java.lang.SecurityManager}
  * does not permit read and/or write access to the underlying files.
+ *
+ * @opensearch.internal
  */
 public class FsBlobContainer extends AbstractBlobContainer {
 
@@ -225,7 +227,7 @@ public void writeBlobAtomic(final String blobName, final InputStream inputStream
     private void writeToPath(InputStream inputStream, Path tempBlobPath, long blobSize) throws IOException {
         try (OutputStream outputStream = Files.newOutputStream(tempBlobPath, StandardOpenOption.CREATE_NEW)) {
             final int bufferSize = blobStore.bufferSizeInBytes();
-            org.opensearch.core.internal.io.Streams.copy(
+            org.opensearch.common.util.io.Streams.copy(
                 inputStream,
                 outputStream,
                 new byte[blobSize < bufferSize ? Math.toIntExact(blobSize) : bufferSize]
diff --git a/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobStore.java b/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobStore.java
index 346100ccb9527..6944e01d8ee24 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobStore.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/fs/FsBlobStore.java
@@ -41,6 +41,11 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 
+/**
+ * FileSystem blob store
+ *
+ * @opensearch.internal
+ */
 public class FsBlobStore implements BlobStore {
 
     private final Path path;
@@ -85,7 +90,7 @@ public void close() {
         // nothing to do here...
     }
 
-    private synchronized Path buildAndCreate(BlobPath path) throws IOException {
+    protected synchronized Path buildAndCreate(BlobPath path) throws IOException {
         Path f = buildPath(path);
         if (readOnly == false) {
             Files.createDirectories(f);
diff --git a/server/src/main/java/org/opensearch/common/blobstore/fs/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/fs/package-info.java
new file mode 100644
index 0000000000000..584d25f12738f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/fs/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base FileSystem Blobstore package. */
+package org.opensearch.common.blobstore.fs;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/package-info.java
new file mode 100644
index 0000000000000..bf7768b185084
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Blob Store package. */
+package org.opensearch.common.blobstore;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/stream/package-info.java
new file mode 100644
index 0000000000000..88d6d433d837f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Abstractions for stream based file transfers */
+package org.opensearch.common.blobstore.stream;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/read/ReadContext.java b/server/src/main/java/org/opensearch/common/blobstore/stream/read/ReadContext.java
new file mode 100644
index 0000000000000..4bdce11ff4f9a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/read/ReadContext.java
@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.io.InputStreamContainer;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Supplier;
+
+/**
+ * ReadContext is used to encapsulate all data needed by <code>BlobContainer#readBlobAsync</code>
+ */
+@ExperimentalApi
+public class ReadContext {
+    private final long blobSize;
+    private final List<StreamPartCreator> asyncPartStreams;
+    private final String blobChecksum;
+
+    public ReadContext(long blobSize, List<StreamPartCreator> asyncPartStreams, String blobChecksum) {
+        this.blobSize = blobSize;
+        this.asyncPartStreams = asyncPartStreams;
+        this.blobChecksum = blobChecksum;
+    }
+
+    public ReadContext(ReadContext readContext) {
+        this.blobSize = readContext.blobSize;
+        this.asyncPartStreams = readContext.asyncPartStreams;
+        this.blobChecksum = readContext.blobChecksum;
+    }
+
+    public String getBlobChecksum() {
+        return blobChecksum;
+    }
+
+    public int getNumberOfParts() {
+        return asyncPartStreams.size();
+    }
+
+    public long getBlobSize() {
+        return blobSize;
+    }
+
+    public List<StreamPartCreator> getPartStreams() {
+        return asyncPartStreams;
+    }
+
+    /**
+     * Functional interface defining an instance that can create an async action
+     * to create a part of an object represented as an InputStreamContainer.
+     */
+    @FunctionalInterface
+    public interface StreamPartCreator extends Supplier<CompletableFuture<InputStreamContainer>> {
+        /**
+         * Kicks off a async process to start streaming.
+         *
+         * @return When the returned future is completed, streaming has
+         * just begun. Clients must fully consume the resulting stream.
+         */
+        @Override
+        CompletableFuture<InputStreamContainer> get();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriter.java b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriter.java
new file mode 100644
index 0000000000000..1a403200249cd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriter.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read.listener;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.io.Channels;
+import org.opensearch.common.io.InputStreamContainer;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.channels.FileChannel;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.function.UnaryOperator;
+
+/**
+ * FilePartWriter transfers the provided stream into the specified file path using a {@link FileChannel}
+ * instance.
+ */
+@InternalApi
+class FilePartWriter {
+    // 8 MB buffer for transfer
+    private static final int BUFFER_SIZE = 8 * 1024 * 2024;
+
+    public static void write(Path fileLocation, InputStreamContainer stream, UnaryOperator<InputStream> rateLimiter) throws IOException {
+        try (FileChannel outputFileChannel = FileChannel.open(fileLocation, StandardOpenOption.WRITE, StandardOpenOption.CREATE)) {
+            try (InputStream inputStream = rateLimiter.apply(stream.getInputStream())) {
+                long streamOffset = stream.getOffset();
+                final byte[] buffer = new byte[BUFFER_SIZE];
+                int bytesRead;
+                while ((bytesRead = inputStream.read(buffer)) != -1) {
+                    Channels.writeToChannel(buffer, 0, bytesRead, outputFileChannel, streamOffset);
+                    streamOffset += bytesRead;
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListener.java b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListener.java
new file mode 100644
index 0000000000000..c77f2384ace0d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListener.java
@@ -0,0 +1,199 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read.listener;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.util.IOUtils;
+import org.opensearch.action.support.GroupedActionListener;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.util.Collection;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.UnaryOperator;
+
+/**
+ * ReadContextListener orchestrates the async file fetch from the {@link org.opensearch.common.blobstore.BlobContainer}
+ * using a {@link ReadContext} callback. On response, it spawns off the download using multiple streams.
+ */
+@InternalApi
+public class ReadContextListener implements ActionListener<ReadContext> {
+    private static final Logger logger = LogManager.getLogger(ReadContextListener.class);
+    private static final String DOWNLOAD_PREFIX = "download.";
+    private final String blobName;
+    private final Path fileLocation;
+    private final String tmpFileName;
+    private final Path tmpFileLocation;
+    private final ActionListener<String> completionListener;
+    private final ThreadPool threadPool;
+    private final UnaryOperator<InputStream> rateLimiter;
+    private final int maxConcurrentStreams;
+
+    public ReadContextListener(
+        String blobName,
+        Path fileLocation,
+        ActionListener<String> completionListener,
+        ThreadPool threadPool,
+        UnaryOperator<InputStream> rateLimiter,
+        int maxConcurrentStreams
+    ) {
+        this.blobName = blobName;
+        this.fileLocation = fileLocation;
+        this.completionListener = completionListener;
+        this.threadPool = threadPool;
+        this.rateLimiter = rateLimiter;
+        this.maxConcurrentStreams = maxConcurrentStreams;
+        this.tmpFileName = DOWNLOAD_PREFIX + UUIDs.randomBase64UUID() + "." + blobName;
+        this.tmpFileLocation = fileLocation.getParent().resolve(tmpFileName);
+    }
+
+    @Override
+    public void onResponse(ReadContext readContext) {
+        logger.debug("Received {} parts for blob {}", readContext.getNumberOfParts(), blobName);
+        final int numParts = readContext.getNumberOfParts();
+        final AtomicBoolean anyPartStreamFailed = new AtomicBoolean(false);
+        final GroupedActionListener<String> groupedListener = new GroupedActionListener<>(getFileCompletionListener(), numParts);
+        final Queue<ReadContext.StreamPartCreator> queue = new ConcurrentLinkedQueue<>(readContext.getPartStreams());
+        final StreamPartProcessor processor = new StreamPartProcessor(
+            queue,
+            anyPartStreamFailed,
+            tmpFileLocation,
+            groupedListener,
+            threadPool.executor(ThreadPool.Names.REMOTE_RECOVERY),
+            rateLimiter
+        );
+        for (int i = 0; i < Math.min(maxConcurrentStreams, queue.size()); i++) {
+            processor.process(queue.poll());
+        }
+    }
+
+    @SuppressForbidden(reason = "need to fsync once all parts received")
+    private ActionListener<Collection<String>> getFileCompletionListener() {
+        return ActionListener.wrap(response -> {
+            logger.trace("renaming temp file [{}] to [{}]", tmpFileLocation, fileLocation);
+            try {
+                IOUtils.fsync(tmpFileLocation, false);
+                Files.move(tmpFileLocation, fileLocation, StandardCopyOption.ATOMIC_MOVE);
+                // sync parent dir metadata
+                IOUtils.fsync(fileLocation.getParent(), true);
+                completionListener.onResponse(blobName);
+            } catch (IOException e) {
+                logger.error("Unable to rename temp file + " + tmpFileLocation, e);
+                completionListener.onFailure(e);
+            }
+        }, e -> {
+            try {
+                Files.deleteIfExists(tmpFileLocation);
+            } catch (IOException ex) {
+                logger.warn("Unable to clean temp file {}", tmpFileLocation);
+            }
+            completionListener.onFailure(e);
+        });
+    }
+
+    /*
+     * For Tests
+     */
+    Path getTmpFileLocation() {
+        return tmpFileLocation;
+    }
+
+    @Override
+    public void onFailure(Exception e) {
+        completionListener.onFailure(e);
+    }
+
+    private static class StreamPartProcessor {
+        private static final RuntimeException CANCELED_PART_EXCEPTION = new RuntimeException(
+            "Canceled part download due to previous failure"
+        );
+        private final Queue<ReadContext.StreamPartCreator> queue;
+        private final AtomicBoolean anyPartStreamFailed;
+        private final Path fileLocation;
+        private final GroupedActionListener<String> completionListener;
+        private final Executor executor;
+        private final UnaryOperator<InputStream> rateLimiter;
+
+        private StreamPartProcessor(
+            Queue<ReadContext.StreamPartCreator> queue,
+            AtomicBoolean anyPartStreamFailed,
+            Path fileLocation,
+            GroupedActionListener<String> completionListener,
+            Executor executor,
+            UnaryOperator<InputStream> rateLimiter
+        ) {
+            this.queue = queue;
+            this.anyPartStreamFailed = anyPartStreamFailed;
+            this.fileLocation = fileLocation;
+            this.completionListener = completionListener;
+            this.executor = executor;
+            this.rateLimiter = rateLimiter;
+        }
+
+        private void process(ReadContext.StreamPartCreator supplier) {
+            if (supplier == null) {
+                return;
+            }
+            supplier.get().whenCompleteAsync((blobPartStreamContainer, throwable) -> {
+                if (throwable != null) {
+                    processFailure(throwable instanceof Exception ? (Exception) throwable : new RuntimeException(throwable));
+                } else if (anyPartStreamFailed.get()) {
+                    processFailure(CANCELED_PART_EXCEPTION);
+                } else {
+                    try {
+                        FilePartWriter.write(fileLocation, blobPartStreamContainer, rateLimiter);
+                        completionListener.onResponse(fileLocation.toString());
+
+                        // Upon successfully completing a file part, pull another
+                        // file part off the queue to trigger asynchronous processing
+                        process(queue.poll());
+                    } catch (Exception e) {
+                        processFailure(e);
+                    }
+                }
+            }, executor);
+        }
+
+        private void processFailure(Exception e) {
+            if (anyPartStreamFailed.getAndSet(true) == false) {
+                completionListener.onFailure(e);
+
+                // Drain the queue of pending part downloads. These can be discarded
+                // since they haven't started any work yet, but the listener must be
+                // notified for each part.
+                Object item = queue.poll();
+                while (item != null) {
+                    completionListener.onFailure(CANCELED_PART_EXCEPTION);
+                    item = queue.poll();
+                }
+            } else {
+                completionListener.onFailure(e);
+            }
+            try {
+                Files.deleteIfExists(fileLocation);
+            } catch (IOException ex) {
+                // Die silently
+                logger.info("Failed to delete file {} on stream failure: {}", fileLocation, ex);
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/package-info.java
new file mode 100644
index 0000000000000..fe670fe3eb25c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/read/listener/package-info.java
@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Abstractions for stream based file reads from the blob store.
+ * Provides listeners for performing the necessary async read operations to perform
+ * multi stream reads for blobs from the container.
+ * */
+package org.opensearch.common.blobstore.stream.read.listener;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/read/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/stream/read/package-info.java
new file mode 100644
index 0000000000000..a9e2ca35c1fa6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/read/package-info.java
@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Abstractions for stream based file reads from the blob store.
+ * Provides support for async reads from the blob container.
+ * */
+package org.opensearch.common.blobstore.stream.read;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/write/StreamContextSupplier.java b/server/src/main/java/org/opensearch/common/blobstore/stream/write/StreamContextSupplier.java
new file mode 100644
index 0000000000000..24a47a5f25b2d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/write/StreamContextSupplier.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.write;
+
+import org.opensearch.common.StreamContext;
+
+/**
+ * Will return the <code>StreamContext</code> to the caller given the part size
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface StreamContextSupplier {
+
+    /**
+     * @param partSize The size of a single part to be uploaded
+     * @return The <code>StreamContext</code> based on the part size provided
+     */
+    StreamContext supplyStreamContext(long partSize);
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/write/WriteContext.java b/server/src/main/java/org/opensearch/common/blobstore/stream/write/WriteContext.java
new file mode 100644
index 0000000000000..e74462f82400d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/write/WriteContext.java
@@ -0,0 +1,134 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.write;
+
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.StreamContext;
+
+import java.io.IOException;
+
+/**
+ * WriteContext is used to encapsulate all data needed by <code>BlobContainer#writeStreams</code>
+ *
+ * @opensearch.internal
+ */
+public class WriteContext {
+
+    private final String fileName;
+    private final StreamContextSupplier streamContextSupplier;
+    private final long fileSize;
+    private final boolean failIfAlreadyExists;
+    private final WritePriority writePriority;
+    private final CheckedConsumer<Boolean, IOException> uploadFinalizer;
+    private final boolean doRemoteDataIntegrityCheck;
+    private final Long expectedChecksum;
+
+    /**
+     * Construct a new WriteContext object
+     *
+     * @param fileName                   The name of the file being uploaded
+     * @param streamContextSupplier      A supplier that will provide StreamContext to the plugin
+     * @param fileSize                   The total size of the file being uploaded
+     * @param failIfAlreadyExists        A boolean to fail the upload is the file exists
+     * @param writePriority              The <code>WritePriority</code> of this upload
+     * @param doRemoteDataIntegrityCheck A boolean to inform vendor plugins whether remote data integrity checks need to be done
+     * @param expectedChecksum           This parameter expected only when the vendor plugin is expected to do server side data integrity verification
+     */
+    public WriteContext(
+        String fileName,
+        StreamContextSupplier streamContextSupplier,
+        long fileSize,
+        boolean failIfAlreadyExists,
+        WritePriority writePriority,
+        CheckedConsumer<Boolean, IOException> uploadFinalizer,
+        boolean doRemoteDataIntegrityCheck,
+        @Nullable Long expectedChecksum
+    ) {
+        this.fileName = fileName;
+        this.streamContextSupplier = streamContextSupplier;
+        this.fileSize = fileSize;
+        this.failIfAlreadyExists = failIfAlreadyExists;
+        this.writePriority = writePriority;
+        this.uploadFinalizer = uploadFinalizer;
+        this.doRemoteDataIntegrityCheck = doRemoteDataIntegrityCheck;
+        this.expectedChecksum = expectedChecksum;
+    }
+
+    /**
+     * Copy constructor used by overriding class
+     */
+    protected WriteContext(WriteContext writeContext) {
+        this.fileName = writeContext.fileName;
+        this.streamContextSupplier = writeContext.streamContextSupplier;
+        this.fileSize = writeContext.fileSize;
+        this.failIfAlreadyExists = writeContext.failIfAlreadyExists;
+        this.writePriority = writeContext.writePriority;
+        this.uploadFinalizer = writeContext.uploadFinalizer;
+        this.doRemoteDataIntegrityCheck = writeContext.doRemoteDataIntegrityCheck;
+        this.expectedChecksum = writeContext.expectedChecksum;
+    }
+
+    /**
+     * @return The file name
+     */
+    public String getFileName() {
+        return fileName;
+    }
+
+    /**
+     * @return The boolean representing whether to fail the file upload if it exists
+     */
+    public boolean isFailIfAlreadyExists() {
+        return failIfAlreadyExists;
+    }
+
+    /**
+     * @param partSize The size of a single part to be uploaded
+     * @return The stream context which will be used by the plugin to initialize streams from the file
+     */
+    public StreamContext getStreamProvider(long partSize) {
+        return streamContextSupplier.supplyStreamContext(partSize);
+    }
+
+    /**
+     * @return The total size of the file
+     */
+    public long getFileSize() {
+        return fileSize;
+    }
+
+    /**
+     * @return The <code>WritePriority</code> of the upload
+     */
+    public WritePriority getWritePriority() {
+        return writePriority;
+    }
+
+    /**
+     * @return The <code>UploadFinalizer</code> for this upload
+     */
+    public CheckedConsumer<Boolean, IOException> getUploadFinalizer() {
+        return uploadFinalizer;
+    }
+
+    /**
+     * @return A boolean for whether remote data integrity check has to be done for this upload or not
+     */
+    public boolean doRemoteDataIntegrityCheck() {
+        return doRemoteDataIntegrityCheck;
+    }
+
+    /**
+     * @return The CRC32 checksum associated with this file
+     */
+    public Long getExpectedChecksum() {
+        return expectedChecksum;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/write/WritePriority.java b/server/src/main/java/org/opensearch/common/blobstore/stream/write/WritePriority.java
new file mode 100644
index 0000000000000..b8c0b52f93a3c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/write/WritePriority.java
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.write;
+
+/**
+ * WritePriority for upload
+ *
+ * @opensearch.internal
+ */
+public enum WritePriority {
+    NORMAL,
+    HIGH
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/stream/write/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/stream/write/package-info.java
new file mode 100644
index 0000000000000..a2f0e634f0a0a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/stream/write/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Abstractions for stream based file writes */
+package org.opensearch.common.blobstore.stream.write;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/support/AbstractBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/support/AbstractBlobContainer.java
index ec498404c8803..de167b0a2423f 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/support/AbstractBlobContainer.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/support/AbstractBlobContainer.java
@@ -37,6 +37,8 @@
 
 /**
  * A base abstract blob container that implements higher level container methods.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractBlobContainer implements BlobContainer {
 
diff --git a/server/src/main/java/org/opensearch/common/blobstore/support/FilterBlobContainer.java b/server/src/main/java/org/opensearch/common/blobstore/support/FilterBlobContainer.java
index 1cf50027b2994..1965aee7f7ef6 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/support/FilterBlobContainer.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/support/FilterBlobContainer.java
@@ -44,6 +44,11 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
+/**
+ * Filter blob container.
+ *
+ * @opensearch.internal
+ */
 public abstract class FilterBlobContainer implements BlobContainer {
 
     private final BlobContainer delegate;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/support/PlainBlobMetadata.java b/server/src/main/java/org/opensearch/common/blobstore/support/PlainBlobMetadata.java
index a97566fd3fc33..8d2aee199ea61 100644
--- a/server/src/main/java/org/opensearch/common/blobstore/support/PlainBlobMetadata.java
+++ b/server/src/main/java/org/opensearch/common/blobstore/support/PlainBlobMetadata.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.blobstore.BlobMetadata;
 
+/**
+ * Plain blob metadata
+ *
+ * @opensearch.internal
+ */
 public class PlainBlobMetadata implements BlobMetadata {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/support/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/support/package-info.java
new file mode 100644
index 0000000000000..f93e9583a4c8b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/support/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Support classes package for BlobStore implementation. */
+package org.opensearch.common.blobstore.support;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainer.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainer.java
new file mode 100644
index 0000000000000..5808f51f01efc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainer.java
@@ -0,0 +1,264 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.CheckedTriFunction;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeInputStream;
+import org.opensearch.common.blobstore.transfer.stream.ResettableCheckedInputStream;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.common.util.ByteUtils;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Objects;
+import java.util.zip.CRC32;
+
+import com.jcraft.jzlib.JZlib;
+
+/**
+ * RemoteTransferContainer is an encapsulation for managing file transfers.
+ *
+ * @opensearch.internal
+ */
+public class RemoteTransferContainer implements Closeable {
+
+    private int numberOfParts;
+    private long partSize;
+    private long lastPartSize;
+
+    private final long contentLength;
+    private final SetOnce<InputStream[]> inputStreams = new SetOnce<>();
+    private final String fileName;
+    private final String remoteFileName;
+    private final boolean failTransferIfFileExists;
+    private final WritePriority writePriority;
+    private final long expectedChecksum;
+    private final OffsetRangeInputStreamSupplier offsetRangeInputStreamSupplier;
+    private final boolean isRemoteDataIntegritySupported;
+
+    private static final Logger log = LogManager.getLogger(RemoteTransferContainer.class);
+
+    /**
+     * Construct a new RemoteTransferContainer object
+     *
+     * @param fileName                       Name of the local file
+     * @param remoteFileName                 Name of the remote file
+     * @param contentLength                  Total content length of the file to be uploaded
+     * @param failTransferIfFileExists       A boolean to determine if upload has to be failed if file exists
+     * @param writePriority                  The {@link WritePriority} of current upload
+     * @param offsetRangeInputStreamSupplier A supplier to create OffsetRangeInputStreams
+     * @param expectedChecksum               The expected checksum value for the file being uploaded. This checksum will be used for local or remote data integrity checks
+     * @param isRemoteDataIntegritySupported A boolean to signify whether the remote repository supports server side data integrity verification
+     */
+    public RemoteTransferContainer(
+        String fileName,
+        String remoteFileName,
+        long contentLength,
+        boolean failTransferIfFileExists,
+        WritePriority writePriority,
+        OffsetRangeInputStreamSupplier offsetRangeInputStreamSupplier,
+        long expectedChecksum,
+        boolean isRemoteDataIntegritySupported
+    ) {
+        this.fileName = fileName;
+        this.remoteFileName = remoteFileName;
+        this.contentLength = contentLength;
+        this.failTransferIfFileExists = failTransferIfFileExists;
+        this.writePriority = writePriority;
+        this.offsetRangeInputStreamSupplier = offsetRangeInputStreamSupplier;
+        this.expectedChecksum = expectedChecksum;
+        this.isRemoteDataIntegritySupported = isRemoteDataIntegritySupported;
+    }
+
+    /**
+     * @return The {@link  WriteContext} for the current upload
+     */
+    public WriteContext createWriteContext() {
+        return new WriteContext(
+            remoteFileName,
+            this::supplyStreamContext,
+            contentLength,
+            failTransferIfFileExists,
+            writePriority,
+            this::finalizeUpload,
+            isRemoteDataIntegrityCheckPossible(),
+            isRemoteDataIntegrityCheckPossible() ? expectedChecksum : null
+        );
+    }
+
+    // package-private for testing
+
+    /**
+     * This method is called to create the {@link StreamContext} object that will be used by the vendor plugin to
+     * open streams during uploads. Calling this method won't actually create the streams, for that the consumer needs
+     * to call {@link StreamContext#provideStream}
+     *
+     * @param partSize Part sizes of all parts apart from the last one, which is determined internally
+     * @return The {@link StreamContext} object that will be used by the vendor plugin to retrieve streams during upload
+     */
+    StreamContext supplyStreamContext(long partSize) {
+        try {
+            return this.openMultipartStreams(partSize);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private StreamContext openMultipartStreams(long partSize) throws IOException {
+        if (inputStreams.get() != null) {
+            throw new IOException("Multi-part streams are already created.");
+        }
+
+        this.partSize = partSize;
+        this.lastPartSize = (contentLength % partSize) != 0 ? contentLength % partSize : partSize;
+        this.numberOfParts = (int) ((contentLength % partSize) == 0 ? contentLength / partSize : (contentLength / partSize) + 1);
+        InputStream[] streams = new InputStream[numberOfParts];
+        inputStreams.set(streams);
+
+        return new StreamContext(getTransferPartStreamSupplier(), partSize, lastPartSize, numberOfParts);
+    }
+
+    private CheckedTriFunction<Integer, Long, Long, InputStreamContainer, IOException> getTransferPartStreamSupplier() {
+        return ((partNo, size, position) -> {
+            assert inputStreams.get() != null : "expected inputStreams to be initialised";
+            return getMultipartStreamSupplier(partNo, size, position).get();
+        });
+    }
+
+    /**
+     * OffsetRangeInputStreamSupplier is used to get the offset based input streams at runtime
+     */
+    public interface OffsetRangeInputStreamSupplier {
+        OffsetRangeInputStream get(long size, long position) throws IOException;
+    }
+
+    interface LocalStreamSupplier<Stream> {
+        Stream get() throws IOException;
+    }
+
+    private LocalStreamSupplier<InputStreamContainer> getMultipartStreamSupplier(
+        final int streamIdx,
+        final long size,
+        final long position
+    ) {
+        return () -> {
+            try {
+                OffsetRangeInputStream offsetRangeInputStream = offsetRangeInputStreamSupplier.get(size, position);
+                InputStream inputStream = !isRemoteDataIntegrityCheckPossible()
+                    ? new ResettableCheckedInputStream(offsetRangeInputStream, fileName)
+                    : offsetRangeInputStream;
+                Objects.requireNonNull(inputStreams.get())[streamIdx] = inputStream;
+
+                return new InputStreamContainer(inputStream, size, position);
+            } catch (IOException e) {
+                log.error("Failed to create input stream", e);
+                throw e;
+            }
+        };
+    }
+
+    private boolean isRemoteDataIntegrityCheckPossible() {
+        return isRemoteDataIntegritySupported;
+    }
+
+    private void finalizeUpload(boolean uploadSuccessful) throws IOException {
+        if (isRemoteDataIntegrityCheckPossible()) {
+            return;
+        }
+
+        if (uploadSuccessful) {
+            long actualChecksum = getActualChecksum();
+            if (actualChecksum != expectedChecksum) {
+                throw new CorruptIndexException(
+                    "Data integrity check done after upload for file "
+                        + fileName
+                        + " failed, actual checksum: "
+                        + actualChecksum
+                        + ", expected checksum: "
+                        + expectedChecksum,
+                    fileName
+                );
+            }
+        }
+    }
+
+    /**
+     * @return The total content length of current upload
+     */
+    public long getContentLength() {
+        return contentLength;
+    }
+
+    private long getInputStreamChecksum(InputStream inputStream) {
+        assert inputStream instanceof ResettableCheckedInputStream
+            : "expected passed inputStream to be instance of ResettableCheckedInputStream";
+        return ((ResettableCheckedInputStream) inputStream).getChecksum();
+    }
+
+    private long getActualChecksum() {
+        InputStream[] currentInputStreams = Objects.requireNonNull(inputStreams.get());
+        long checksum = getInputStreamChecksum(currentInputStreams[0]);
+        for (int checkSumIdx = 1; checkSumIdx < Objects.requireNonNull(inputStreams.get()).length - 1; checkSumIdx++) {
+            checksum = JZlib.crc32_combine(checksum, getInputStreamChecksum(currentInputStreams[checkSumIdx]), partSize);
+        }
+        if (numberOfParts > 1) {
+            checksum = JZlib.crc32_combine(checksum, getInputStreamChecksum(currentInputStreams[numberOfParts - 1]), lastPartSize);
+        }
+
+        return checksum;
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (inputStreams.get() == null) {
+            log.warn("Input streams cannot be closed since they are not yet set for multi stream upload");
+            return;
+        }
+
+        boolean closeStreamException = false;
+        for (InputStream is : Objects.requireNonNull(inputStreams.get())) {
+            try {
+                if (is != null) {
+                    is.close();
+                }
+            } catch (IOException ex) {
+                closeStreamException = true;
+                // Attempting to close all streams first before throwing exception.
+                log.error("Multipart stream failed to close ", ex);
+            }
+        }
+
+        if (closeStreamException) {
+            throw new IOException("Closure of some of the multi-part streams failed.");
+        }
+    }
+
+    /**
+     * Compute final checksum for IndexInput container checksum footer added by {@link CodecUtil}
+     * @param indexInput IndexInput with checksum in footer
+     * @param checksumBytesLength length of checksum bytes
+     * @return final computed checksum of entire indexInput
+     */
+    public static long checksumOfChecksum(IndexInput indexInput, int checksumBytesLength) throws IOException {
+        long storedChecksum = CodecUtil.retrieveChecksum(indexInput);
+        CRC32 checksumOfChecksum = new CRC32();
+        checksumOfChecksum.update(ByteUtils.toByteArrayBE(storedChecksum));
+        return JZlib.crc32_combine(storedChecksum, checksumOfChecksum.getValue(), checksumBytesLength);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/package-info.java
new file mode 100644
index 0000000000000..779b6538401d0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Contains transfer related utilities for {@link org.opensearch.common.blobstore.BlobContainer} */
+package org.opensearch.common.blobstore.transfer;
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStream.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStream.java
new file mode 100644
index 0000000000000..7ba673ce34d2a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStream.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.channels.Channels;
+import java.nio.channels.FileChannel;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+
+/**
+ * OffsetRangeFileInputStream extends InputStream to read from a specified offset using FileChannel
+ *
+ * @opensearch.internal
+ */
+public class OffsetRangeFileInputStream extends OffsetRangeInputStream {
+    private final InputStream inputStream;
+    private final FileChannel fileChannel;
+
+    private final long actualSizeToRead;
+    // This is the maximum position till stream is to be read. If read methods exceed maxPos then bytes are read
+    // till maxPos. If no byte is left after maxPos, then -1 is returned from read methods.
+    private final long limit;
+    // Position in stream from which read will start.
+    private long counter = 0;
+
+    private long markPointer;
+    private long markCounter;
+
+    /**
+     * Construct a new OffsetRangeFileInputStream object
+     *
+     * @param path Path to the file
+     * @param size Number of bytes that need to be read from specified <code>position</code>
+     * @param position Position from where the read needs to start
+     * @throws IOException When <code>FileChannel#position</code> operation fails
+     */
+    public OffsetRangeFileInputStream(Path path, long size, long position) throws IOException {
+        fileChannel = FileChannel.open(path, StandardOpenOption.READ);
+        fileChannel.position(position);
+        inputStream = Channels.newInputStream(fileChannel);
+        long totalLength = fileChannel.size();
+        this.counter = 0;
+        this.limit = size;
+        if ((totalLength - position) > limit) {
+            actualSizeToRead = limit;
+        } else {
+            actualSizeToRead = totalLength - position;
+        }
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        if (b == null) {
+            throw new NullPointerException();
+        } else if (off < 0 || len < 0 || len > b.length - off) {
+            throw new IndexOutOfBoundsException();
+        }
+        if (fileChannel.position() >= fileChannel.size()) {
+            return -1;
+        }
+        if (fileChannel.position() + len > fileChannel.size()) {
+            len = (int) (fileChannel.size() - fileChannel.position());
+        }
+        if (counter + len > limit) {
+            len = (int) (limit - counter);
+        }
+        if (len <= 0) {
+            return -1;
+        }
+
+        inputStream.read(b, off, len);
+        counter += len;
+        return len;
+    }
+
+    @Override
+    public int read() throws IOException {
+        if (counter++ >= limit) {
+            return -1;
+        }
+        return (fileChannel.position() < fileChannel.size()) ? (inputStream.read() & 0xff) : -1;
+    }
+
+    @Override
+    public boolean markSupported() {
+        return true;
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        try {
+            markPointer = fileChannel.position();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        markCounter = counter;
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        fileChannel.position(markPointer);
+        counter = markCounter;
+    }
+
+    @Override
+    public long getFilePointer() throws IOException {
+        return fileChannel.position();
+    }
+
+    @Override
+    public void close() throws IOException {
+        inputStream.close();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStream.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStream.java
new file mode 100644
index 0000000000000..7518f9ac569b9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStream.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.lucene.store.InputStreamIndexInput;
+
+import java.io.IOException;
+
+/**
+ * OffsetRangeIndexInputStream extends InputStream to read from a specified offset using IndexInput
+ *
+ * @opensearch.internal
+ */
+public class OffsetRangeIndexInputStream extends OffsetRangeInputStream {
+
+    private final InputStreamIndexInput inputStreamIndexInput;
+    private final IndexInput indexInput;
+
+    /**
+     * Construct a new OffsetRangeIndexInputStream object
+     *
+     * @param indexInput IndexInput opened on the file to read from
+     * @param size The maximum length to read from specified <code>position</code>
+     * @param position Position from where read needs to start
+     * @throws IOException When <code>IndexInput#seek</code> operation fails
+     */
+    public OffsetRangeIndexInputStream(IndexInput indexInput, long size, long position) throws IOException {
+        indexInput.seek(position);
+        this.indexInput = indexInput;
+        this.inputStreamIndexInput = new InputStreamIndexInput(indexInput, size);
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        return inputStreamIndexInput.read(b, off, len);
+    }
+
+    @Override
+    public int read() throws IOException {
+        return inputStreamIndexInput.read();
+    }
+
+    @Override
+    public boolean markSupported() {
+        return inputStreamIndexInput.markSupported();
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        inputStreamIndexInput.mark(readlimit);
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        inputStreamIndexInput.reset();
+    }
+
+    @Override
+    public long getFilePointer() throws IOException {
+        return indexInput.getFilePointer();
+    }
+
+    @Override
+    public void close() throws IOException {
+        inputStreamIndexInput.close();
+        indexInput.close();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeInputStream.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeInputStream.java
new file mode 100644
index 0000000000000..e8b889db1f3b0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeInputStream.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * OffsetRangeInputStream is an abstract class that extends from {@link InputStream}
+ * and adds a method to get the file pointer to the specific part being read
+ *
+ * @opensearch.internal
+ */
+public abstract class OffsetRangeInputStream extends InputStream {
+    public abstract long getFilePointer() throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStream.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStream.java
new file mode 100644
index 0000000000000..b455999bbed0c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStream.java
@@ -0,0 +1,83 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import org.apache.lucene.store.RateLimiter;
+import org.opensearch.common.StreamLimiter;
+
+import java.io.IOException;
+import java.util.function.Supplier;
+
+/**
+ * Rate Limits an {@link OffsetRangeInputStream}
+ *
+ * @opensearch.internal
+ */
+public class RateLimitingOffsetRangeInputStream extends OffsetRangeInputStream {
+
+    private final StreamLimiter streamLimiter;
+
+    private final OffsetRangeInputStream delegate;
+
+    /**
+     * The ctor for RateLimitingOffsetRangeInputStream
+     * @param delegate the underlying {@link OffsetRangeInputStream}
+     * @param rateLimiterSupplier the supplier for {@link RateLimiter}
+     * @param listener the listener to be invoked on rate limits
+     */
+    public RateLimitingOffsetRangeInputStream(
+        OffsetRangeInputStream delegate,
+        Supplier<RateLimiter> rateLimiterSupplier,
+        StreamLimiter.Listener listener
+    ) {
+        this.streamLimiter = new StreamLimiter(rateLimiterSupplier, listener);
+        this.delegate = delegate;
+    }
+
+    @Override
+    public int read() throws IOException {
+        int b = delegate.read();
+        streamLimiter.maybePause(1);
+        return b;
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        int n = delegate.read(b, off, len);
+        if (n > 0) {
+            streamLimiter.maybePause(n);
+        }
+        return n;
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        delegate.mark(readlimit);
+    }
+
+    @Override
+    public boolean markSupported() {
+        return delegate.markSupported();
+    }
+
+    @Override
+    public long getFilePointer() throws IOException {
+        return delegate.getFilePointer();
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        delegate.reset();
+    }
+
+    @Override
+    public void close() throws IOException {
+        delegate.close();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStream.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStream.java
new file mode 100644
index 0000000000000..2f779b14c48cf
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStream.java
@@ -0,0 +1,128 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+
+import com.jcraft.jzlib.CRC32;
+
+/**
+ * ResettableCheckedInputStream is a modified implementation of {@link java.util.zip.CheckedInputStream} that supports
+ * mark and reset and modifies the file checksum during mark and reset calls.
+ *
+ * @opensearch.internal
+ */
+public class ResettableCheckedInputStream extends FilterInputStream {
+    private final CRC32 checksum;
+    private final CRC32 markedChecksum;
+    private final long startPos;
+    private final String file;
+    private final OffsetRangeInputStream offsetRangeInputStream;
+
+    /**
+     * Creates a new ResettableCheckedInputStream object
+     *
+     * @param offsetRangeInputStream   The underlying input stream
+     * @param file Name of the file
+     */
+    public ResettableCheckedInputStream(OffsetRangeInputStream offsetRangeInputStream, String file) throws IOException {
+        super(offsetRangeInputStream);
+        this.checksum = new CRC32();
+        this.markedChecksum = new CRC32();
+        this.offsetRangeInputStream = offsetRangeInputStream;
+        this.startPos = offsetRangeInputStream.getFilePointer();
+        this.file = file;
+    }
+
+    /**
+     * Reads a byte. Will block if no input is available.
+     * @return the byte read, or -1 if the end of the stream is reached.
+     * @exception IOException if an I/O error has occurred
+     */
+    public int read() throws IOException {
+        byte[] buffer = new byte[1];
+        int len = read(buffer, 0, 1);
+        if (len == -1) {
+            return -1;
+        }
+        return buffer[0];
+    }
+
+    /**
+     * Reads into an array of bytes. If <code>len</code> is not zero, the method
+     * blocks until some input is available; otherwise, no
+     * bytes are read and <code>0</code> is returned.
+     * @param buf the buffer into which the data is read
+     * @param off the start offset in the destination array <code>buf</code>
+     * @param len the maximum number of bytes read
+     * @return    the actual number of bytes read, or -1 if the end
+     *            of the stream is reached.
+     * @exception  NullPointerException If <code>buf</code> is <code>null</code>.
+     * @exception  IndexOutOfBoundsException If <code>off</code> is negative,
+     * <code>len</code> is negative, or <code>len</code> is greater than
+     * <code>buf.length - off</code>
+     * @exception IOException if an I/O error has occurred
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        len = in.read(buf, off, len);
+        if (len != -1) {
+            checksum.update(buf, off, len);
+        }
+        return len;
+    }
+
+    /**
+     * Skips specified number of bytes of input.
+     * @param n the number of bytes to skip
+     * @return the actual number of bytes skipped
+     * @exception IOException if an I/O error has occurred
+     */
+    public long skip(long n) throws IOException {
+        byte[] buf = new byte[512];
+        long total = 0;
+        while (total < n) {
+            long len = n - total;
+            len = read(buf, 0, len < buf.length ? (int) len : buf.length);
+            if (len == -1) {
+                return total;
+            }
+            total += len;
+        }
+        return total;
+    }
+
+    /**
+     * Returns the Checksum for this input stream.
+     * @return the Checksum value
+     */
+    public long getChecksum() {
+        return checksum.getValue();
+    }
+
+    @Override
+    public boolean markSupported() {
+        return true;
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        markedChecksum.reset(checksum.getValue());
+        super.mark(readlimit);
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        if (startPos == offsetRangeInputStream.getFilePointer()) {
+            return;
+        }
+        checksum.reset(markedChecksum.getValue());
+        super.reset();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/package-info.java b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/package-info.java
new file mode 100644
index 0000000000000..c5e7e45b9f015
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/blobstore/transfer/stream/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Contains encapsulations to create streams for part uploads */
+package org.opensearch.common.blobstore.transfer.stream;
diff --git a/server/src/main/java/org/opensearch/common/breaker/ChildMemoryCircuitBreaker.java b/server/src/main/java/org/opensearch/common/breaker/ChildMemoryCircuitBreaker.java
index 7698771f51170..de4e6ad433c55 100644
--- a/server/src/main/java/org/opensearch/common/breaker/ChildMemoryCircuitBreaker.java
+++ b/server/src/main/java/org/opensearch/common/breaker/ChildMemoryCircuitBreaker.java
@@ -34,7 +34,9 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.indices.breaker.BreakerSettings;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 
@@ -42,6 +44,8 @@
 
 /**
  * Breaker that will check a parent's when incrementing
+ *
+ * @opensearch.internal
  */
 public class ChildMemoryCircuitBreaker implements CircuitBreaker {
 
@@ -268,6 +272,11 @@ public void setLimitAndOverhead(long limit, double overhead) {
         this.limitAndOverhead = new LimitAndOverhead(limit, overhead);
     }
 
+    /**
+     * Breaker limit and overhead info
+     *
+     * @opensearch.internal
+     */
     private static class LimitAndOverhead {
 
         private final long limit;
diff --git a/server/src/main/java/org/opensearch/common/breaker/NoopCircuitBreaker.java b/server/src/main/java/org/opensearch/common/breaker/NoopCircuitBreaker.java
deleted file mode 100644
index aa6f3769a07ca..0000000000000
--- a/server/src/main/java/org/opensearch/common/breaker/NoopCircuitBreaker.java
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.breaker;
-
-/**
- * A CircuitBreaker that doesn't increment or adjust, and all operations are
- * basically noops
- */
-public class NoopCircuitBreaker implements CircuitBreaker {
-    public static final int LIMIT = -1;
-
-    private final String name;
-
-    public NoopCircuitBreaker(String name) {
-        this.name = name;
-    }
-
-    @Override
-    public void circuitBreak(String fieldName, long bytesNeeded) {
-        // noop
-    }
-
-    @Override
-    public double addEstimateBytesAndMaybeBreak(long bytes, String label) throws CircuitBreakingException {
-        return 0;
-    }
-
-    @Override
-    public long addWithoutBreaking(long bytes) {
-        return 0;
-    }
-
-    @Override
-    public long getUsed() {
-        return 0;
-    }
-
-    @Override
-    public long getLimit() {
-        return LIMIT;
-    }
-
-    @Override
-    public double getOverhead() {
-        return 0;
-    }
-
-    @Override
-    public long getTrippedCount() {
-        return 0;
-    }
-
-    @Override
-    public String getName() {
-        return this.name;
-    }
-
-    @Override
-    public Durability getDurability() {
-        return Durability.PERMANENT;
-    }
-
-    @Override
-    public void setLimitAndOverhead(long limit, double overhead) {}
-}
diff --git a/server/src/main/java/org/opensearch/common/breaker/package-info.java b/server/src/main/java/org/opensearch/common/breaker/package-info.java
new file mode 100644
index 0000000000000..30c5d8d981697
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/breaker/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common Circuit Breaker package. */
+package org.opensearch.common.breaker;
diff --git a/server/src/main/java/org/opensearch/common/bytes/RecyclingBytesStreamOutput.java b/server/src/main/java/org/opensearch/common/bytes/RecyclingBytesStreamOutput.java
index e9a9b96ea81ac..d965899b1fabd 100644
--- a/server/src/main/java/org/opensearch/common/bytes/RecyclingBytesStreamOutput.java
+++ b/server/src/main/java/org/opensearch/common/bytes/RecyclingBytesStreamOutput.java
@@ -35,11 +35,14 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.BytesStream;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.ByteArray;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.ByteArray;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +52,8 @@
  * {@link BigArrays} if needed. The idea is that you can use this for passing data to an API that requires a single {@code byte[]} (or a
  * {@link org.apache.lucene.util.BytesRef}) which you'd prefer to re-use if possible, avoiding excessive allocations, but which may not
  * always be large enough.
+ *
+ * @opensearch.internal
  */
 public class RecyclingBytesStreamOutput extends BytesStream {
 
diff --git a/server/src/main/java/org/opensearch/common/bytes/ReleasableBytesReference.java b/server/src/main/java/org/opensearch/common/bytes/ReleasableBytesReference.java
index 9ed47ef6cbf39..23069c8a377e5 100644
--- a/server/src/main/java/org/opensearch/common/bytes/ReleasableBytesReference.java
+++ b/server/src/main/java/org/opensearch/common/bytes/ReleasableBytesReference.java
@@ -35,9 +35,10 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
 import org.opensearch.common.concurrent.RefCountedReleasable;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -45,6 +46,8 @@
 /**
  * An extension to {@link BytesReference} that requires releasing its content. This
  * class exists to make it explicit when a bytes reference needs to be released, and when not.
+ *
+ * @opensearch.internal
  */
 public final class ReleasableBytesReference implements Releasable, BytesReference {
 
diff --git a/server/src/main/java/org/opensearch/common/bytes/package-info.java b/server/src/main/java/org/opensearch/common/bytes/package-info.java
new file mode 100644
index 0000000000000..96e3db1b7cd06
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/bytes/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base BytesRef package. */
+package org.opensearch.common.bytes;
diff --git a/server/src/main/java/org/opensearch/common/cache/Cache.java b/server/src/main/java/org/opensearch/common/cache/Cache.java
index 8ab0bc9114c0e..0ebef1556424b 100644
--- a/server/src/main/java/org/opensearch/common/cache/Cache.java
+++ b/server/src/main/java/org/opensearch/common/cache/Cache.java
@@ -79,6 +79,8 @@
  *
  * @param <K> The type of the keys
  * @param <V> The type of the values
+ *
+ * @opensearch.internal
  */
 public class Cache<K, V> {
 
@@ -173,6 +175,11 @@ enum State {
         DELETED
     }
 
+    /**
+     * Entry in a cache
+     *
+     * @opensearch.internal
+     */
     static class Entry<K, V> {
         final K key;
         final V value;
@@ -196,6 +203,8 @@ static class Entry<K, V> {
      *
      * @param <K> the type of the keys
      * @param <V> the type of the values
+     *
+     * @opensearch.internal
      */
     private static class CacheSegment<K, V> {
         // read/write lock protecting mutations to the segment
@@ -329,6 +338,11 @@ void remove(K key, V value, Consumer<CompletableFuture<Entry<K, V>>> onRemoval)
             }
         }
 
+        /**
+         * Segment statistics
+         *
+         * @opensearch.internal
+         */
         private static class SegmentStats {
             private final LongAdder hits = new LongAdder();
             private final LongAdder misses = new LongAdder();
@@ -499,9 +513,7 @@ private void put(K key, V value, long now) {
             promote(tuple.v1(), now);
         }
         if (replaced) {
-            removalListener.onRemoval(
-                new RemovalNotification<>(tuple.v2().key, tuple.v2().value, RemovalNotification.RemovalReason.REPLACED)
-            );
+            removalListener.onRemoval(new RemovalNotification<>(tuple.v2().key, tuple.v2().value, RemovalReason.REPLACED));
         }
     }
 
@@ -509,7 +521,7 @@ private void put(K key, V value, long now) {
         try {
             Entry<K, V> entry = f.get();
             try (ReleasableLock ignored = lruLock.acquire()) {
-                delete(entry, RemovalNotification.RemovalReason.INVALIDATED);
+                delete(entry, RemovalReason.INVALIDATED);
             }
         } catch (ExecutionException e) {
             // ok
@@ -520,7 +532,7 @@ private void put(K key, V value, long now) {
 
     /**
      * Invalidate the association for the specified key. A removal notification will be issued for invalidated
-     * entries with {@link org.opensearch.common.cache.RemovalNotification.RemovalReason} INVALIDATED.
+     * entries with {@link RemovalReason} INVALIDATED.
      *
      * @param key the key whose mapping is to be invalidated from the cache
      */
@@ -532,7 +544,7 @@ public void invalidate(K key) {
     /**
      * Invalidate the entry for the specified key and value. If the value provided is not equal to the value in
      * the cache, no removal will occur. A removal notification will be issued for invalidated
-     * entries with {@link org.opensearch.common.cache.RemovalNotification.RemovalReason} INVALIDATED.
+     * entries with {@link RemovalReason} INVALIDATED.
      *
      * @param key the key whose mapping is to be invalidated from the cache
      * @param value the expected value that should be associated with the key
@@ -544,7 +556,7 @@ public void invalidate(K key, V value) {
 
     /**
      * Invalidate all cache entries. A removal notification will be issued for invalidated entries with
-     * {@link org.opensearch.common.cache.RemovalNotification.RemovalReason} INVALIDATED.
+     * {@link RemovalReason} INVALIDATED.
      */
     public void invalidateAll() {
         Entry<K, V> h;
@@ -575,7 +587,7 @@ public void invalidateAll() {
             }
         }
         while (h != null) {
-            removalListener.onRemoval(new RemovalNotification<>(h.key, h.value, RemovalNotification.RemovalReason.INVALIDATED));
+            removalListener.onRemoval(new RemovalNotification<>(h.key, h.value, RemovalReason.INVALIDATED));
             h = h.after;
         }
     }
@@ -693,7 +705,7 @@ public void remove() {
                 segment.remove(entry.key, entry.value, f -> {});
                 try (ReleasableLock ignored = lruLock.acquire()) {
                     current = null;
-                    delete(entry, RemovalNotification.RemovalReason.INVALIDATED);
+                    delete(entry, RemovalReason.INVALIDATED);
                 }
             }
         }
@@ -717,6 +729,11 @@ public CacheStats stats() {
         return new CacheStats(hits, misses, evictions);
     }
 
+    /**
+     * Cache statistics
+     *
+     * @opensearch.internal
+     */
     public static class CacheStats {
         private long hits;
         private long misses;
@@ -777,10 +794,10 @@ private void evictEntry(Entry<K, V> entry) {
         if (segment != null) {
             segment.remove(entry.key, entry.value, f -> {});
         }
-        delete(entry, RemovalNotification.RemovalReason.EVICTED);
+        delete(entry, RemovalReason.EVICTED);
     }
 
-    private void delete(Entry<K, V> entry, RemovalNotification.RemovalReason removalReason) {
+    private void delete(Entry<K, V> entry, RemovalReason removalReason) {
         assert lruLock.isHeldByCurrentThread();
 
         if (unlink(entry)) {
diff --git a/server/src/main/java/org/opensearch/common/cache/CacheBuilder.java b/server/src/main/java/org/opensearch/common/cache/CacheBuilder.java
index 9fd340ccca320..b6d7979aa4108 100644
--- a/server/src/main/java/org/opensearch/common/cache/CacheBuilder.java
+++ b/server/src/main/java/org/opensearch/common/cache/CacheBuilder.java
@@ -37,6 +37,11 @@
 import java.util.Objects;
 import java.util.function.ToLongBiFunction;
 
+/**
+ * The cache builder.
+ *
+ * @opensearch.internal
+ */
 public class CacheBuilder<K, V> {
     private long maximumWeight = -1;
     private long expireAfterAccessNanos = -1;
diff --git a/server/src/main/java/org/opensearch/common/cache/CacheLoader.java b/server/src/main/java/org/opensearch/common/cache/CacheLoader.java
index 721a1a9885527..3c80fe5d66d5d 100644
--- a/server/src/main/java/org/opensearch/common/cache/CacheLoader.java
+++ b/server/src/main/java/org/opensearch/common/cache/CacheLoader.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.cache;
 
+/**
+ * An interface for a cache loader.
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface CacheLoader<K, V> {
     V load(K key) throws Exception;
diff --git a/server/src/main/java/org/opensearch/common/cache/RemovalListener.java b/server/src/main/java/org/opensearch/common/cache/RemovalListener.java
index eb84108319b16..369313f9f93f4 100644
--- a/server/src/main/java/org/opensearch/common/cache/RemovalListener.java
+++ b/server/src/main/java/org/opensearch/common/cache/RemovalListener.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.cache;
 
+/**
+ * Listener for removing an element from the cache
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface RemovalListener<K, V> {
     void onRemoval(RemovalNotification<K, V> notification);
diff --git a/server/src/main/java/org/opensearch/common/cache/RemovalNotification.java b/server/src/main/java/org/opensearch/common/cache/RemovalNotification.java
index 89ab6decff43f..6d355b2122460 100644
--- a/server/src/main/java/org/opensearch/common/cache/RemovalNotification.java
+++ b/server/src/main/java/org/opensearch/common/cache/RemovalNotification.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common.cache;
 
+/**
+ * Notification when an element is removed from the cache
+ *
+ * @opensearch.internal
+ */
 public class RemovalNotification<K, V> {
-    public enum RemovalReason {
-        REPLACED,
-        INVALIDATED,
-        EVICTED
-    }
 
     private final K key;
     private final V value;
diff --git a/server/src/main/java/org/opensearch/common/cache/RemovalReason.java b/server/src/main/java/org/opensearch/common/cache/RemovalReason.java
new file mode 100644
index 0000000000000..e5d795c093547
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/cache/RemovalReason.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.cache;
+
+/**
+ * Reason for notification removal
+ *
+ * @opensearch.internal
+ */
+public enum RemovalReason {
+    REPLACED,
+    INVALIDATED,
+    EVICTED,
+    EXPLICIT,
+    CAPACITY
+}
diff --git a/server/src/main/java/org/opensearch/common/cache/Weigher.java b/server/src/main/java/org/opensearch/common/cache/Weigher.java
new file mode 100644
index 0000000000000..98e40b0e61bc5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/cache/Weigher.java
@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.cache;
+
+/**
+ * A class that can determine the weight of a value. The total weight threshold
+ * is used to determine when an eviction is required.
+ *
+ * @opensearch.internal
+ */
+public interface Weigher<V> {
+
+    /**
+     * Measures an object's weight to determine how many units of capacity that
+     * the value consumes. A value must consume a minimum of one unit.
+     *
+     * @param value the object to weigh
+     * @return the object's weight
+     */
+    long weightOf(V value);
+}
diff --git a/server/src/main/java/org/opensearch/common/cache/package-info.java b/server/src/main/java/org/opensearch/common/cache/package-info.java
new file mode 100644
index 0000000000000..174f719b33d17
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/cache/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Cache package. */
+package org.opensearch.common.cache;
diff --git a/server/src/main/java/org/opensearch/common/collect/CopyOnWriteHashMap.java b/server/src/main/java/org/opensearch/common/collect/CopyOnWriteHashMap.java
index 5066ffa76ba0a..5ce77cdc75fe5 100644
--- a/server/src/main/java/org/opensearch/common/collect/CopyOnWriteHashMap.java
+++ b/server/src/main/java/org/opensearch/common/collect/CopyOnWriteHashMap.java
@@ -62,6 +62,8 @@
  * it is better suited for work-loads that are not too write-intensive.
  *
  * @see <a href="http://en.wikipedia.org/wiki/Hash_array_mapped_trie">the wikipedia page</a>
+ *
+ * @opensearch.internal
  */
 public final class CopyOnWriteHashMap<K, V> extends AbstractMap<K, V> {
 
@@ -87,6 +89,8 @@ public static <K, V> CopyOnWriteHashMap<K, V> copyOf(Map<? extends K, ? extends
 
     /**
      * Abstraction of a node, implemented by both inner and leaf nodes.
+     *
+     * @opensearch.internal
      */
     private abstract static class Node<K, V> {
 
@@ -124,6 +128,8 @@ private abstract static class Node<K, V> {
 
     /**
      * A leaf of the tree where all hashes are equal. Values are added and retrieved in linear time.
+     *
+     * @opensearch.internal
      */
     private static class Leaf<K, V> extends Node<K, V> {
 
@@ -247,6 +253,8 @@ public static <T> T[] insertElement(final T[] array, final T element, final int
      *
      * As a consequence, the number of slots in an inner node is equal to the
      * number of one bits in the bitmap.
+     *
+     * @opensearch.internal
      */
     private static class InnerNode<K, V> extends Node<K, V> {
 
@@ -440,6 +448,11 @@ InnerNode<K, V> remove(Object key, int hash) {
 
     }
 
+    /**
+     * Iterates over an entry
+     *
+     * @opensearch.internal
+     */
     private static class EntryIterator<K, V> implements Iterator<Map.Entry<K, V>> {
 
         private final Deque<Map.Entry<K, V>> entries;
diff --git a/server/src/main/java/org/opensearch/common/collect/EvictingQueue.java b/server/src/main/java/org/opensearch/common/collect/EvictingQueue.java
index fd2c23af30e35..3d505b8c38a37 100644
--- a/server/src/main/java/org/opensearch/common/collect/EvictingQueue.java
+++ b/server/src/main/java/org/opensearch/common/collect/EvictingQueue.java
@@ -60,6 +60,8 @@
  * full queue, elements are evicted from the head of the queue to accommodate the new elements.
  *
  * @param <T> The type of elements in the queue.
+ *
+ * @opensearch.internal
  */
 public class EvictingQueue<T> implements Queue<T> {
     private final int maximumSize;
diff --git a/server/src/main/java/org/opensearch/common/collect/HppcMaps.java b/server/src/main/java/org/opensearch/common/collect/HppcMaps.java
deleted file mode 100644
index 55696568de47f..0000000000000
--- a/server/src/main/java/org/opensearch/common/collect/HppcMaps.java
+++ /dev/null
@@ -1,160 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.ObjectLookupContainer;
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-
-import java.util.Iterator;
-
-public final class HppcMaps {
-
-    private HppcMaps() {}
-
-    /**
-     * Returns a new map with the given number of expected elements.
-     *
-     * @param expectedElements
-     *          The expected number of elements guaranteed not to cause buffer
-     *          expansion (inclusive).
-     */
-    public static <K, V> ObjectObjectHashMap<K, V> newMap(int expectedElements) {
-        return new ObjectObjectHashMap<>(expectedElements);
-    }
-
-    /**
-     * Returns a new map with a default initial capacity.
-     */
-    public static <K, V> ObjectObjectHashMap<K, V> newMap() {
-        return newMap(16);
-    }
-
-    /**
-     * Returns a map like {@link #newMap()} that does not accept <code>null</code> keys
-     */
-    public static <K, V> ObjectObjectHashMap<K, V> newNoNullKeysMap() {
-        return ensureNoNullKeys(16);
-    }
-
-    /**
-     * Returns a map like {@link #newMap(int)} that does not accept <code>null</code> keys
-     *
-     * @param expectedElements
-     *          The expected number of elements guaranteed not to cause buffer
-     *          expansion (inclusive).
-     */
-    public static <K, V> ObjectObjectHashMap<K, V> newNoNullKeysMap(int expectedElements) {
-        return ensureNoNullKeys(expectedElements);
-    }
-
-    /**
-     * Wraps the given map and prevent adding of <code>null</code> keys.
-     *
-     * @param expectedElements
-     *          The expected number of elements guaranteed not to cause buffer
-     *          expansion (inclusive).
-     */
-    public static <K, V> ObjectObjectHashMap<K, V> ensureNoNullKeys(int expectedElements) {
-        return new ObjectObjectHashMap<K, V>(expectedElements) {
-            @Override
-            public V put(K key, V value) {
-                if (key == null) {
-                    throw new IllegalArgumentException("Map key must not be null");
-                }
-                return super.put(key, value);
-            }
-        };
-    }
-
-    /**
-     * @return an intersection view over the two specified containers (which can be KeyContainer or ObjectHashSet).
-     */
-    // Hppc has forEach, but this means we need to build an intermediate set, with this method we just iterate
-    // over each unique value without creating a third set.
-    public static <T> Iterable<T> intersection(ObjectLookupContainer<T> container1, final ObjectLookupContainer<T> container2) {
-        assert container1 != null && container2 != null;
-        final Iterator<ObjectCursor<T>> iterator = container1.iterator();
-        final Iterator<T> intersection = new Iterator<T>() {
-
-            T current;
-
-            @Override
-            public boolean hasNext() {
-                if (iterator.hasNext()) {
-                    do {
-                        T next = iterator.next().value;
-                        if (container2.contains(next)) {
-                            current = next;
-                            return true;
-                        }
-                    } while (iterator.hasNext());
-                }
-                return false;
-            }
-
-            @Override
-            public T next() {
-                return current;
-            }
-
-            @Override
-            public void remove() {
-                throw new UnsupportedOperationException();
-            }
-        };
-        return new Iterable<T>() {
-            @Override
-            public Iterator<T> iterator() {
-                return intersection;
-            }
-        };
-    }
-
-    public static final class Object {
-        public static final class Integer {
-            public static <V> ObjectIntHashMap<V> ensureNoNullKeys(int capacity, float loadFactor) {
-                return new ObjectIntHashMap<V>(capacity, loadFactor) {
-                    @Override
-                    public int put(V key, int value) {
-                        if (key == null) {
-                            throw new IllegalArgumentException("Map key must not be null");
-                        }
-                        return super.put(key, value);
-                    }
-                };
-            }
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/collect/ImmutableOpenIntMap.java b/server/src/main/java/org/opensearch/common/collect/ImmutableOpenIntMap.java
deleted file mode 100644
index a5ebb19423732..0000000000000
--- a/server/src/main/java/org/opensearch/common/collect/ImmutableOpenIntMap.java
+++ /dev/null
@@ -1,403 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import com.carrotsearch.hppc.IntCollection;
-import com.carrotsearch.hppc.IntContainer;
-import com.carrotsearch.hppc.IntLookupContainer;
-import com.carrotsearch.hppc.IntObjectAssociativeContainer;
-import com.carrotsearch.hppc.IntObjectHashMap;
-import com.carrotsearch.hppc.IntObjectMap;
-import com.carrotsearch.hppc.ObjectContainer;
-import com.carrotsearch.hppc.cursors.IntCursor;
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.predicates.IntObjectPredicate;
-import com.carrotsearch.hppc.predicates.IntPredicate;
-import com.carrotsearch.hppc.procedures.IntObjectProcedure;
-
-import java.util.Iterator;
-import java.util.Map;
-
-/**
- * An immutable map implementation based on open hash map.
- * <p>
- * Can be constructed using a {@link #builder()}, or using {@link #builder(org.opensearch.common.collect.ImmutableOpenIntMap)}
- * (which is an optimized option to copy over existing content and modify it).
- */
-public final class ImmutableOpenIntMap<VType> implements Iterable<IntObjectCursor<VType>> {
-
-    private final IntObjectHashMap<VType> map;
-
-    private ImmutableOpenIntMap(IntObjectHashMap<VType> map) {
-        this.map = map;
-    }
-
-    /**
-     * @return Returns the value associated with the given key or the default value
-     * for the key type, if the key is not associated with any value.
-     * <p>
-     * <b>Important note:</b> For primitive type values, the value returned for a non-existing
-     * key may not be the default value of the primitive type (it may be any value previously
-     * assigned to that slot).
-     */
-    public VType get(int key) {
-        return map.get(key);
-    }
-
-    /**
-     * Returns <code>true</code> if this container has an association to a value for
-     * the given key.
-     */
-    public boolean containsKey(int key) {
-        return map.containsKey(key);
-    }
-
-    /**
-     * @return Returns the current size (number of assigned keys) in the container.
-     */
-    public int size() {
-        return map.size();
-    }
-
-    /**
-     * @return Return <code>true</code> if this hash map contains no assigned keys.
-     */
-    public boolean isEmpty() {
-        return map.isEmpty();
-    }
-
-    /**
-     * Returns a cursor over the entries (key-value pairs) in this map. The iterator is
-     * implemented as a cursor and it returns <b>the same cursor instance</b> on every
-     * call to {@link java.util.Iterator#next()}. To read the current key and value use the cursor's
-     * public fields. An example is shown below.
-     * <pre>
-     * for (IntShortCursor c : intShortMap)
-     * {
-     *     System.out.println(&quot;index=&quot; + c.index
-     *       + &quot; key=&quot; + c.key
-     *       + &quot; value=&quot; + c.value);
-     * }
-     * </pre>
-     * <p>
-     * The <code>index</code> field inside the cursor gives the internal index inside
-     * the container's implementation. The interpretation of this index depends on
-     * to the container.
-     */
-    @Override
-    public Iterator<IntObjectCursor<VType>> iterator() {
-        return map.iterator();
-    }
-
-    /**
-     * Returns a specialized view of the keys of this associated container.
-     * The view additionally implements {@link com.carrotsearch.hppc.ObjectLookupContainer}.
-     */
-    public IntLookupContainer keys() {
-        return map.keys();
-    }
-
-    /**
-     * Returns a direct iterator over the keys.
-     */
-    public Iterator<Integer> keysIt() {
-        final Iterator<IntCursor> iterator = map.keys().iterator();
-        return new Iterator<Integer>() {
-            @Override
-            public boolean hasNext() {
-                return iterator.hasNext();
-            }
-
-            @Override
-            public Integer next() {
-                return iterator.next().value;
-            }
-
-            @Override
-            public void remove() {
-                throw new UnsupportedOperationException();
-            }
-        };
-    }
-
-    /**
-     * @return Returns a container with all values stored in this map.
-     */
-    public ObjectContainer<VType> values() {
-        return map.values();
-    }
-
-    /**
-     * Returns a direct iterator over the keys.
-     */
-    public Iterator<VType> valuesIt() {
-        final Iterator<ObjectCursor<VType>> iterator = map.values().iterator();
-        return new Iterator<VType>() {
-            @Override
-            public boolean hasNext() {
-                return iterator.hasNext();
-            }
-
-            @Override
-            public VType next() {
-                return iterator.next().value;
-            }
-
-            @Override
-            public void remove() {
-                throw new UnsupportedOperationException();
-            }
-        };
-    }
-
-    @Override
-    public String toString() {
-        return map.toString();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-
-        ImmutableOpenIntMap that = (ImmutableOpenIntMap) o;
-
-        if (!map.equals(that.map)) return false;
-
-        return true;
-    }
-
-    @Override
-    public int hashCode() {
-        return map.hashCode();
-    }
-
-    @SuppressWarnings("unchecked")
-    private static final ImmutableOpenIntMap EMPTY = new ImmutableOpenIntMap(new IntObjectHashMap());
-
-    @SuppressWarnings("unchecked")
-    public static <VType> ImmutableOpenIntMap<VType> of() {
-        return EMPTY;
-    }
-
-    public static <VType> Builder<VType> builder() {
-        return new Builder<>();
-    }
-
-    public static <VType> Builder<VType> builder(int size) {
-        return new Builder<>(size);
-    }
-
-    public static <VType> Builder<VType> builder(ImmutableOpenIntMap<VType> map) {
-        return new Builder<>(map);
-    }
-
-    public static class Builder<VType> implements IntObjectMap<VType> {
-
-        private IntObjectHashMap<VType> map;
-
-        public Builder() {
-            // noinspection unchecked
-            this(EMPTY);
-        }
-
-        public Builder(int size) {
-            this.map = new IntObjectHashMap<>(size);
-        }
-
-        public Builder(ImmutableOpenIntMap<VType> map) {
-            this.map = map.map.clone();
-        }
-
-        /**
-         * Builds a new instance of the
-         */
-        public ImmutableOpenIntMap<VType> build() {
-            IntObjectHashMap<VType> map = this.map;
-            this.map = null; // nullify the map, so any operation post build will fail! (hackish, but safest)
-            return new ImmutableOpenIntMap<>(map);
-        }
-
-        /**
-         * Puts all the entries in the map to the builder.
-         */
-        public Builder<VType> putAll(Map<Integer, VType> map) {
-            for (Map.Entry<Integer, VType> entry : map.entrySet()) {
-                this.map.put(entry.getKey(), entry.getValue());
-            }
-            return this;
-        }
-
-        /**
-         * A put operation that can be used in the fluent pattern.
-         */
-        public Builder<VType> fPut(int key, VType value) {
-            map.put(key, value);
-            return this;
-        }
-
-        @Override
-        public VType put(int key, VType value) {
-            return map.put(key, value);
-        }
-
-        @Override
-        public VType get(int key) {
-            return map.get(key);
-        }
-
-        @Override
-        public VType getOrDefault(int kType, VType vType) {
-            return map.getOrDefault(kType, vType);
-        }
-
-        /**
-         * Remove that can be used in the fluent pattern.
-         */
-        public Builder<VType> fRemove(int key) {
-            map.remove(key);
-            return this;
-        }
-
-        @Override
-        public VType remove(int key) {
-            return map.remove(key);
-        }
-
-        @Override
-        public Iterator<IntObjectCursor<VType>> iterator() {
-            return map.iterator();
-        }
-
-        @Override
-        public boolean containsKey(int key) {
-            return map.containsKey(key);
-        }
-
-        @Override
-        public int size() {
-            return map.size();
-        }
-
-        @Override
-        public boolean isEmpty() {
-            return map.isEmpty();
-        }
-
-        @Override
-        public void clear() {
-            map.clear();
-        }
-
-        @Override
-        public int putAll(IntObjectAssociativeContainer<? extends VType> container) {
-            return map.putAll(container);
-        }
-
-        @Override
-        public int putAll(Iterable<? extends IntObjectCursor<? extends VType>> iterable) {
-            return map.putAll(iterable);
-        }
-
-        @Override
-        public int removeAll(IntContainer container) {
-            return map.removeAll(container);
-        }
-
-        @Override
-        public int removeAll(IntPredicate predicate) {
-            return map.removeAll(predicate);
-        }
-
-        @Override
-        public <T extends IntObjectProcedure<? super VType>> T forEach(T procedure) {
-            return map.forEach(procedure);
-        }
-
-        @Override
-        public IntCollection keys() {
-            return map.keys();
-        }
-
-        @Override
-        public ObjectContainer<VType> values() {
-            return map.values();
-        }
-
-        @Override
-        public int removeAll(IntObjectPredicate<? super VType> predicate) {
-            return map.removeAll(predicate);
-        }
-
-        @Override
-        public <T extends IntObjectPredicate<? super VType>> T forEach(T predicate) {
-            return map.forEach(predicate);
-        }
-
-        @Override
-        public int indexOf(int key) {
-            return map.indexOf(key);
-        }
-
-        @Override
-        public boolean indexExists(int index) {
-            return map.indexExists(index);
-        }
-
-        @Override
-        public VType indexGet(int index) {
-            return map.indexGet(index);
-        }
-
-        @Override
-        public VType indexReplace(int index, VType newValue) {
-            return map.indexReplace(index, newValue);
-        }
-
-        @Override
-        public void indexInsert(int index, int key, VType value) {
-            map.indexInsert(index, key, value);
-        }
-
-        @Override
-        public void release() {
-            map.release();
-        }
-
-        @Override
-        public String visualizeKeyDistribution(int characters) {
-            return map.visualizeKeyDistribution(characters);
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/collect/ImmutableOpenMap.java b/server/src/main/java/org/opensearch/common/collect/ImmutableOpenMap.java
deleted file mode 100644
index 82b9afd1d3c08..0000000000000
--- a/server/src/main/java/org/opensearch/common/collect/ImmutableOpenMap.java
+++ /dev/null
@@ -1,422 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import com.carrotsearch.hppc.ObjectCollection;
-import com.carrotsearch.hppc.ObjectContainer;
-import com.carrotsearch.hppc.ObjectLookupContainer;
-import com.carrotsearch.hppc.ObjectObjectAssociativeContainer;
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.ObjectObjectMap;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-import com.carrotsearch.hppc.predicates.ObjectObjectPredicate;
-import com.carrotsearch.hppc.predicates.ObjectPredicate;
-import com.carrotsearch.hppc.procedures.ObjectObjectProcedure;
-
-import java.util.Iterator;
-import java.util.Map;
-
-/**
- * An immutable map implementation based on open hash map.
- * <p>
- * Can be constructed using a {@link #builder()}, or using {@link #builder(ImmutableOpenMap)} (which is an optimized
- * option to copy over existing content and modify it).
- */
-public final class ImmutableOpenMap<KType, VType> implements Iterable<ObjectObjectCursor<KType, VType>> {
-
-    private final ObjectObjectHashMap<KType, VType> map;
-
-    private ImmutableOpenMap(ObjectObjectHashMap<KType, VType> map) {
-        this.map = map;
-    }
-
-    /**
-     * @return Returns the value associated with the given key or the default value
-     * for the key type, if the key is not associated with any value.
-     * <p>
-     * <b>Important note:</b> For primitive type values, the value returned for a non-existing
-     * key may not be the default value of the primitive type (it may be any value previously
-     * assigned to that slot).
-     */
-    public VType get(KType key) {
-        return map.get(key);
-    }
-
-    /**
-     * @return Returns the value associated with the given key or the provided default value if the
-     * key is not associated with any value.
-     */
-    public VType getOrDefault(KType key, VType defaultValue) {
-        return map.getOrDefault(key, defaultValue);
-    }
-
-    /**
-     * Returns <code>true</code> if this container has an association to a value for
-     * the given key.
-     */
-    public boolean containsKey(KType key) {
-        return map.containsKey(key);
-    }
-
-    /**
-     * @return Returns the current size (number of assigned keys) in the container.
-     */
-    public int size() {
-        return map.size();
-    }
-
-    /**
-     * @return Return <code>true</code> if this hash map contains no assigned keys.
-     */
-    public boolean isEmpty() {
-        return map.isEmpty();
-    }
-
-    /**
-     * Returns a cursor over the entries (key-value pairs) in this map. The iterator is
-     * implemented as a cursor and it returns <b>the same cursor instance</b> on every
-     * call to {@link Iterator#next()}. To read the current key and value use the cursor's
-     * public fields. An example is shown below.
-     * <pre>
-     * for (IntShortCursor c : intShortMap)
-     * {
-     *     System.out.println(&quot;index=&quot; + c.index
-     *       + &quot; key=&quot; + c.key
-     *       + &quot; value=&quot; + c.value);
-     * }
-     * </pre>
-     * <p>
-     * The <code>index</code> field inside the cursor gives the internal index inside
-     * the container's implementation. The interpretation of this index depends on
-     * to the container.
-     */
-    @Override
-    public Iterator<ObjectObjectCursor<KType, VType>> iterator() {
-        return map.iterator();
-    }
-
-    /**
-     * Returns a specialized view of the keys of this associated container.
-     * The view additionally implements {@link ObjectLookupContainer}.
-     */
-    public ObjectLookupContainer<KType> keys() {
-        return map.keys();
-    }
-
-    /**
-     * Returns a direct iterator over the keys.
-     */
-    public Iterator<KType> keysIt() {
-        final Iterator<ObjectCursor<KType>> iterator = map.keys().iterator();
-        return new Iterator<KType>() {
-            @Override
-            public boolean hasNext() {
-                return iterator.hasNext();
-            }
-
-            @Override
-            public KType next() {
-                return iterator.next().value;
-            }
-
-            @Override
-            public void remove() {
-                throw new UnsupportedOperationException();
-            }
-        };
-    }
-
-    /**
-     * @return Returns a container with all values stored in this map.
-     */
-    public ObjectContainer<VType> values() {
-        return map.values();
-    }
-
-    /**
-     * Returns a direct iterator over the keys.
-     */
-    public Iterator<VType> valuesIt() {
-        final Iterator<ObjectCursor<VType>> iterator = map.values().iterator();
-        return new Iterator<VType>() {
-            @Override
-            public boolean hasNext() {
-                return iterator.hasNext();
-            }
-
-            @Override
-            public VType next() {
-                return iterator.next().value;
-            }
-
-            @Override
-            public void remove() {
-                throw new UnsupportedOperationException();
-            }
-        };
-    }
-
-    @Override
-    public String toString() {
-        return map.toString();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-
-        ImmutableOpenMap that = (ImmutableOpenMap) o;
-
-        if (!map.equals(that.map)) return false;
-
-        return true;
-    }
-
-    @Override
-    public int hashCode() {
-        return map.hashCode();
-    }
-
-    @SuppressWarnings("unchecked")
-    private static final ImmutableOpenMap EMPTY = new ImmutableOpenMap(new ObjectObjectHashMap());
-
-    @SuppressWarnings("unchecked")
-    public static <KType, VType> ImmutableOpenMap<KType, VType> of() {
-        return EMPTY;
-    }
-
-    /**
-     * @return  An immutable copy of the given map
-     */
-    public static <KType, VType> ImmutableOpenMap<KType, VType> copyOf(ObjectObjectMap<KType, VType> map) {
-        Builder<KType, VType> builder = builder();
-        builder.putAll(map);
-        return builder.build();
-    }
-
-    public static <KType, VType> Builder<KType, VType> builder() {
-        return new Builder<>();
-    }
-
-    public static <KType, VType> Builder<KType, VType> builder(int size) {
-        return new Builder<>(size);
-    }
-
-    public static <KType, VType> Builder<KType, VType> builder(ImmutableOpenMap<KType, VType> map) {
-        return new Builder<>(map);
-    }
-
-    public static class Builder<KType, VType> implements ObjectObjectMap<KType, VType> {
-        private ObjectObjectHashMap<KType, VType> map;
-
-        public Builder() {
-            // noinspection unchecked
-            this(EMPTY);
-        }
-
-        public Builder(int size) {
-            this.map = new ObjectObjectHashMap<>(size);
-        }
-
-        public Builder(ImmutableOpenMap<KType, VType> map) {
-            this.map = map.map.clone();
-        }
-
-        /**
-         * Builds a new instance of the
-         */
-        public ImmutableOpenMap<KType, VType> build() {
-            ObjectObjectHashMap<KType, VType> map = this.map;
-            this.map = null; // nullify the map, so any operation post build will fail! (hackish, but safest)
-            return new ImmutableOpenMap<>(map);
-        }
-
-        /**
-         * Puts all the entries in the map to the builder.
-         */
-        public Builder<KType, VType> putAll(Map<KType, VType> map) {
-            for (Map.Entry<KType, VType> entry : map.entrySet()) {
-                this.map.put(entry.getKey(), entry.getValue());
-            }
-            return this;
-        }
-
-        /**
-         * A put operation that can be used in the fluent pattern.
-         */
-        public Builder<KType, VType> fPut(KType key, VType value) {
-            map.put(key, value);
-            return this;
-        }
-
-        @Override
-        public VType put(KType key, VType value) {
-            return map.put(key, value);
-        }
-
-        @Override
-        public VType get(KType key) {
-            return map.get(key);
-        }
-
-        @Override
-        public VType getOrDefault(KType kType, VType vType) {
-            return map.getOrDefault(kType, vType);
-        }
-
-        @Override
-        public int putAll(ObjectObjectAssociativeContainer<? extends KType, ? extends VType> container) {
-            return map.putAll(container);
-        }
-
-        @Override
-        public int putAll(Iterable<? extends ObjectObjectCursor<? extends KType, ? extends VType>> iterable) {
-            return map.putAll(iterable);
-        }
-
-        /**
-         * Remove that can be used in the fluent pattern.
-         */
-        public Builder<KType, VType> fRemove(KType key) {
-            map.remove(key);
-            return this;
-        }
-
-        @Override
-        public VType remove(KType key) {
-            return map.remove(key);
-        }
-
-        @Override
-        public Iterator<ObjectObjectCursor<KType, VType>> iterator() {
-            return map.iterator();
-        }
-
-        @Override
-        public boolean containsKey(KType key) {
-            return map.containsKey(key);
-        }
-
-        @Override
-        public int size() {
-            return map.size();
-        }
-
-        @Override
-        public boolean isEmpty() {
-            return map.isEmpty();
-        }
-
-        @Override
-        public int removeAll(ObjectContainer<? super KType> container) {
-            return map.removeAll(container);
-        }
-
-        @Override
-        public int removeAll(ObjectPredicate<? super KType> predicate) {
-            return map.removeAll(predicate);
-        }
-
-        @Override
-        public <T extends ObjectObjectProcedure<? super KType, ? super VType>> T forEach(T procedure) {
-            return map.forEach(procedure);
-        }
-
-        @Override
-        public void clear() {
-            map.clear();
-        }
-
-        @Override
-        public ObjectCollection<KType> keys() {
-            return map.keys();
-        }
-
-        @Override
-        public ObjectContainer<VType> values() {
-            return map.values();
-        }
-
-        @SuppressWarnings("unchecked")
-        public <K, V> Builder<K, V> cast() {
-            return (Builder) this;
-        }
-
-        @Override
-        public int removeAll(ObjectObjectPredicate<? super KType, ? super VType> predicate) {
-            return map.removeAll(predicate);
-        }
-
-        @Override
-        public <T extends ObjectObjectPredicate<? super KType, ? super VType>> T forEach(T predicate) {
-            return map.forEach(predicate);
-        }
-
-        @Override
-        public int indexOf(KType key) {
-            return map.indexOf(key);
-        }
-
-        @Override
-        public boolean indexExists(int index) {
-            return map.indexExists(index);
-        }
-
-        @Override
-        public VType indexGet(int index) {
-            return map.indexGet(index);
-        }
-
-        @Override
-        public VType indexReplace(int index, VType newValue) {
-            return map.indexReplace(index, newValue);
-        }
-
-        @Override
-        public void indexInsert(int index, KType key, VType value) {
-            map.indexInsert(index, key, value);
-        }
-
-        @Override
-        public void release() {
-            map.release();
-        }
-
-        @Override
-        public String visualizeKeyDistribution(int characters) {
-            return map.visualizeKeyDistribution(characters);
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/collect/Iterators.java b/server/src/main/java/org/opensearch/common/collect/Iterators.java
deleted file mode 100644
index a76f4246b1780..0000000000000
--- a/server/src/main/java/org/opensearch/common/collect/Iterators.java
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.collect;
-
-import java.util.Iterator;
-import java.util.NoSuchElementException;
-
-public class Iterators {
-    public static <T> Iterator<T> concat(Iterator<? extends T>... iterators) {
-        if (iterators == null) {
-            throw new NullPointerException("iterators");
-        }
-
-        // explicit generic type argument needed for type inference
-        return new ConcatenatedIterator<T>(iterators);
-    }
-
-    static class ConcatenatedIterator<T> implements Iterator<T> {
-        private final Iterator<? extends T>[] iterators;
-        private int index = 0;
-
-        ConcatenatedIterator(Iterator<? extends T>... iterators) {
-            if (iterators == null) {
-                throw new NullPointerException("iterators");
-            }
-            for (int i = 0; i < iterators.length; i++) {
-                if (iterators[i] == null) {
-                    throw new NullPointerException("iterators[" + i + "]");
-                }
-            }
-            this.iterators = iterators;
-        }
-
-        @Override
-        public boolean hasNext() {
-            boolean hasNext = false;
-            while (index < iterators.length && !(hasNext = iterators[index].hasNext())) {
-                index++;
-            }
-
-            return hasNext;
-        }
-
-        @Override
-        public T next() {
-            if (!hasNext()) {
-                throw new NoSuchElementException();
-            }
-            return iterators[index].next();
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/collect/package-info.java b/server/src/main/java/org/opensearch/common/collect/package-info.java
new file mode 100644
index 0000000000000..6cd7b11582bb8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/collect/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base collections package. */
+package org.opensearch.common.collect;
diff --git a/server/src/main/java/org/opensearch/common/compress/CompressedXContent.java b/server/src/main/java/org/opensearch/common/compress/CompressedXContent.java
index f15e213b9a773..550bc5b3fd524 100644
--- a/server/src/main/java/org/opensearch/common/compress/CompressedXContent.java
+++ b/server/src/main/java/org/opensearch/common/compress/CompressedXContent.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.common.compress;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -54,6 +56,8 @@
  * data using a compressed representation in order to require less permanent
  * memory. Note that the compressed string might still sometimes need to be
  * decompressed in order to perform equality checks or to compute hash codes.
+ *
+ * @opensearch.internal
  */
 public final class CompressedXContent {
 
@@ -83,7 +87,7 @@ private CompressedXContent(byte[] compressed, int crc32) {
      */
     public CompressedXContent(ToXContent xcontent, ToXContent.Params params) throws IOException {
         BytesStreamOutput bStream = new BytesStreamOutput();
-        OutputStream compressedStream = CompressorFactory.COMPRESSOR.threadLocalOutputStream(bStream);
+        OutputStream compressedStream = CompressorRegistry.defaultCompressor().threadLocalOutputStream(bStream);
         CRC32 crc32 = new CRC32();
         OutputStream checkedStream = new CheckedOutputStream(compressedStream, crc32);
         try (XContentBuilder builder = XContentFactory.jsonBuilder(checkedStream)) {
@@ -105,20 +109,20 @@ public CompressedXContent(ToXContent xcontent, ToXContent.Params params) throws
      * that may already be compressed.
      */
     public CompressedXContent(BytesReference data) throws IOException {
-        Compressor compressor = CompressorFactory.compressor(data);
+        Compressor compressor = CompressorRegistry.compressor(data);
         if (compressor != null) {
             // already compressed...
             this.bytes = BytesReference.toBytes(data);
             this.crc32 = crc32(uncompressed());
         } else {
-            this.bytes = BytesReference.toBytes(CompressorFactory.COMPRESSOR.compress(data));
+            this.bytes = BytesReference.toBytes(CompressorRegistry.defaultCompressor().compress(data));
             this.crc32 = crc32(data);
         }
         assertConsistent();
     }
 
     private void assertConsistent() {
-        assert CompressorFactory.compressor(new BytesArray(bytes)) != null;
+        assert CompressorRegistry.compressor(new BytesArray(bytes)) != null;
         assert this.crc32 == crc32(uncompressed());
     }
 
@@ -143,7 +147,7 @@ public BytesReference compressedReference() {
     /** Return the uncompressed bytes. */
     public BytesReference uncompressed() {
         try {
-            return CompressorFactory.uncompress(new BytesArray(bytes));
+            return CompressorRegistry.uncompress(new BytesArray(bytes));
         } catch (IOException e) {
             throw new IllegalStateException("Cannot decompress compressed string", e);
         }
diff --git a/server/src/main/java/org/opensearch/common/compress/CompressorFactory.java b/server/src/main/java/org/opensearch/common/compress/CompressorFactory.java
deleted file mode 100644
index 79d785296f9f5..0000000000000
--- a/server/src/main/java/org/opensearch/common/compress/CompressorFactory.java
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.compress;
-
-import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-
-import java.io.IOException;
-import java.util.Objects;
-
-public class CompressorFactory {
-
-    public static final Compressor COMPRESSOR = new DeflateCompressor();
-
-    public static boolean isCompressed(BytesReference bytes) {
-        return compressor(bytes) != null;
-    }
-
-    @Nullable
-    public static Compressor compressor(BytesReference bytes) {
-        if (COMPRESSOR.isCompressed(bytes)) {
-            // bytes should be either detected as compressed or as xcontent,
-            // if we have bytes that can be either detected as compressed or
-            // as a xcontent, we have a problem
-            assert XContentHelper.xContentType(bytes) == null;
-            return COMPRESSOR;
-        }
-
-        XContentType contentType = XContentHelper.xContentType(bytes);
-        if (contentType == null) {
-            if (isAncient(bytes)) {
-                throw new IllegalStateException("unsupported compression: index was created before v2.0.0.beta1 and wasn't upgraded?");
-            }
-            throw new NotXContentException("Compressor detection can only be called on some xcontent bytes or compressed xcontent bytes");
-        }
-
-        return null;
-    }
-
-    /** true if the bytes were compressed with LZF*/
-    private static boolean isAncient(BytesReference bytes) {
-        return bytes.length() >= 3 && bytes.get(0) == 'Z' && bytes.get(1) == 'V' && (bytes.get(2) == 0 || bytes.get(2) == 1);
-    }
-
-    /**
-     * Uncompress the provided data, data can be detected as compressed using {@link #isCompressed(BytesReference)}.
-     * @throws NullPointerException a NullPointerException will be thrown when bytes is null
-     */
-    public static BytesReference uncompressIfNeeded(BytesReference bytes) throws IOException {
-        Compressor compressor = compressor(Objects.requireNonNull(bytes, "the BytesReference must not be null"));
-        return compressor == null ? bytes : compressor.uncompress(bytes);
-    }
-
-    /** Decompress the provided {@link BytesReference}. */
-    public static BytesReference uncompress(BytesReference bytes) throws IOException {
-        Compressor compressor = compressor(bytes);
-        if (compressor == null) {
-            throw new NotCompressedException();
-        }
-        return compressor.uncompress(bytes);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/compress/DeflateCompressor.java b/server/src/main/java/org/opensearch/common/compress/DeflateCompressor.java
index b622ac6d3f640..3ccac1a941741 100644
--- a/server/src/main/java/org/opensearch/common/compress/DeflateCompressor.java
+++ b/server/src/main/java/org/opensearch/common/compress/DeflateCompressor.java
@@ -32,10 +32,12 @@
 
 package org.opensearch.common.compress;
 
-import org.opensearch.Assertions;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
 
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
@@ -51,6 +53,9 @@
 
 /**
  * {@link Compressor} implementation based on the DEFLATE compression algorithm.
+ *
+ * @opensearch.api - registered name requires BWC support
+ * @opensearch.experimental - class methods might change
  */
 public class DeflateCompressor implements Compressor {
 
@@ -59,6 +64,15 @@ public class DeflateCompressor implements Compressor {
     // enough so that no stream starting with these bytes could be detected as
     // a XContent
     private static final byte[] HEADER = new byte[] { 'D', 'F', 'L', '\0' };
+
+    /**
+     * The name to register the compressor by
+     *
+     * @opensearch.api - requires BWC support
+     */
+    @PublicApi(since = "2.10.0")
+    public static String NAME = "DEFLATE";
+
     // 3 is a good trade-off between speed and compression ratio
     private static final int LEVEL = 3;
     // We use buffering on the input and output of in/def-laters in order to
@@ -155,16 +169,9 @@ public InputStream threadLocalInputStream(InputStream in) throws IOException {
      * @return             decompressing stream
      */
     public static InputStream inputStream(InputStream in, boolean threadLocal) throws IOException {
-        final byte[] headerBytes = new byte[HEADER.length];
-        int len = 0;
-        while (len < headerBytes.length) {
-            final int read = in.read(headerBytes, len, headerBytes.length - len);
-            if (read == -1) {
-                break;
-            }
-            len += read;
-        }
-        if (len != HEADER.length || Arrays.equals(headerBytes, HEADER) == false) {
+        final byte[] header = in.readNBytes(HEADER.length);
+
+        if (Arrays.equals(header, HEADER) == false) {
             throw new IllegalArgumentException("Input stream is not compressed with DEFLATE!");
         }
 
@@ -250,9 +257,11 @@ public BytesReference uncompress(BytesReference bytesReference) throws IOExcepti
         } finally {
             inflater.reset();
         }
-        final BytesReference res = buffer.copyBytes();
-        buffer.reset();
-        return res;
+        try {
+            return buffer.copyBytes();
+        } finally {
+            buffer.reset();
+        }
     }
 
     // Reusable Deflater reference. Note: This is a separate instance from the one used for the compressing stream wrapper because we
@@ -269,8 +278,10 @@ public BytesReference compress(BytesReference bytesReference) throws IOException
         } finally {
             deflater.reset();
         }
-        final BytesReference res = buffer.copyBytes();
-        buffer.reset();
-        return res;
+        try {
+            return buffer.copyBytes();
+        } finally {
+            buffer.reset();
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/common/compress/package-info.java b/server/src/main/java/org/opensearch/common/compress/package-info.java
new file mode 100644
index 0000000000000..38fbba9076ca8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/compress/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base compression package. */
+package org.opensearch.common.compress;
diff --git a/server/src/main/java/org/opensearch/common/compress/spi/ServerCompressorProvider.java b/server/src/main/java/org/opensearch/common/compress/spi/ServerCompressorProvider.java
new file mode 100644
index 0000000000000..42036f8d88610
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/compress/spi/ServerCompressorProvider.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.compress.spi;
+
+import org.opensearch.common.compress.DeflateCompressor;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.spi.CompressorProvider;
+
+import java.util.AbstractMap.SimpleEntry;
+import java.util.List;
+import java.util.Map.Entry;
+
+/**
+ * Default {@link Compressor} implementations provided by the
+ * opensearch core library
+ *
+ * @opensearch.internal
+ *
+ * @deprecated This class is deprecated and will be removed when the {@link DeflateCompressor} is moved to the compress
+ * library as a default compression option
+ */
+@Deprecated
+public class ServerCompressorProvider implements CompressorProvider {
+    /** Returns the concrete {@link Compressor}s provided by the server module */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @Override
+    public List<Entry<String, Compressor>> getCompressors() {
+        return List.of(new SimpleEntry(DeflateCompressor.NAME, new DeflateCompressor()));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/compress/spi/package-info.java b/server/src/main/java/org/opensearch/common/compress/spi/package-info.java
new file mode 100644
index 0000000000000..a8019b23c7d90
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/compress/spi/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Service Provider Interface for registering the{@link org.opensearch.common.compress.DeflateCompressor} with the
+ * {@link org.opensearch.core.compress.CompressorRegistry}.
+ *
+ * Note: this will be refactored to the {@code :libs:opensearch-compress} library after other dependency classes are
+ * refactored.
+ */
+package org.opensearch.common.compress.spi;
diff --git a/server/src/main/java/org/opensearch/common/concurrent/AutoCloseableRefCounted.java b/server/src/main/java/org/opensearch/common/concurrent/AutoCloseableRefCounted.java
new file mode 100644
index 0000000000000..926eb9cb6fd45
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/concurrent/AutoCloseableRefCounted.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.concurrent;
+
+import org.opensearch.common.util.concurrent.RefCounted;
+
+/**
+ * Adapter class that enables a {@link RefCounted} implementation to function like an {@link AutoCloseable}.
+ * The {@link #close()} API invokes {@link RefCounted#decRef()} and ensures idempotency using a {@link OneWayGate}.
+ *
+ * @opensearch.internal
+ */
+public class AutoCloseableRefCounted<T extends RefCounted> implements AutoCloseable {
+
+    private final T ref;
+    private final OneWayGate gate;
+
+    public AutoCloseableRefCounted(T ref) {
+        this.ref = ref;
+        gate = new OneWayGate();
+    }
+
+    public T get() {
+        return ref;
+    }
+
+    @Override
+    public void close() {
+        if (gate.close()) {
+            ref.decRef();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/concurrent/GatedAutoCloseable.java b/server/src/main/java/org/opensearch/common/concurrent/GatedAutoCloseable.java
deleted file mode 100644
index cb819c0320e91..0000000000000
--- a/server/src/main/java/org/opensearch/common/concurrent/GatedAutoCloseable.java
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.concurrent;
-
-/**
- * Decorator class that wraps an object reference with a {@link Runnable} that is
- * invoked when {@link #close()} is called. The internal {@link OneWayGate} instance ensures
- * that this is invoked only once. See also {@link GatedCloseable}
- */
-public class GatedAutoCloseable<T> implements AutoCloseable {
-
-    private final T ref;
-    private final Runnable onClose;
-    private final OneWayGate gate;
-
-    public GatedAutoCloseable(T ref, Runnable onClose) {
-        this.ref = ref;
-        this.onClose = onClose;
-        gate = new OneWayGate();
-    }
-
-    public T get() {
-        return ref;
-    }
-
-    @Override
-    public void close() {
-        if (gate.close()) {
-            onClose.run();
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/concurrent/GatedCloseable.java b/server/src/main/java/org/opensearch/common/concurrent/GatedCloseable.java
index d98e4cca8d561..8bf620ee2cd50 100644
--- a/server/src/main/java/org/opensearch/common/concurrent/GatedCloseable.java
+++ b/server/src/main/java/org/opensearch/common/concurrent/GatedCloseable.java
@@ -21,7 +21,9 @@
 /**
  * Decorator class that wraps an object reference with a {@link CheckedRunnable} that is
  * invoked when {@link #close()} is called. The internal {@link OneWayGate} instance ensures
- * that this is invoked only once. See also {@link GatedAutoCloseable}
+ * that this is invoked only once. See also {@link AutoCloseableRefCounted}
+ *
+ * @opensearch.internal
  */
 public class GatedCloseable<T> implements Closeable {
 
diff --git a/server/src/main/java/org/opensearch/common/concurrent/OneWayGate.java b/server/src/main/java/org/opensearch/common/concurrent/OneWayGate.java
index 76625094f3ca6..b7ddd755503b5 100644
--- a/server/src/main/java/org/opensearch/common/concurrent/OneWayGate.java
+++ b/server/src/main/java/org/opensearch/common/concurrent/OneWayGate.java
@@ -18,6 +18,8 @@
 /**
  * Encapsulates logic for a one-way gate. Guarantees idempotency via the {@link AtomicBoolean} instance
  * and the return value of the {@link #close()} function.
+ *
+ * @opensearch.internal
  */
 public class OneWayGate {
 
diff --git a/server/src/main/java/org/opensearch/common/concurrent/RefCountedReleasable.java b/server/src/main/java/org/opensearch/common/concurrent/RefCountedReleasable.java
index 975f2295d7c32..9ef73a672c1ad 100644
--- a/server/src/main/java/org/opensearch/common/concurrent/RefCountedReleasable.java
+++ b/server/src/main/java/org/opensearch/common/concurrent/RefCountedReleasable.java
@@ -20,6 +20,8 @@
  * Decorator class that wraps an object reference as a {@link AbstractRefCounted} instance.
  * In addition to a {@link String} name, it accepts a {@link Runnable} shutdown hook that is
  * invoked when the reference count reaches zero i.e. on {@link #closeInternal()}.
+ *
+ * @opensearch.internal
  */
 public class RefCountedReleasable<T> extends AbstractRefCounted implements Releasable {
 
@@ -43,6 +45,8 @@ public T get() {
 
     @Override
     protected void closeInternal() {
-        shutdownRunnable.run();
+        if (shutdownRunnable != null) {
+            shutdownRunnable.run();
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/common/concurrent/package-info.java b/server/src/main/java/org/opensearch/common/concurrent/package-info.java
new file mode 100644
index 0000000000000..886920af509ee
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/concurrent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Concurrency package. */
+package org.opensearch.common.concurrent;
diff --git a/server/src/main/java/org/opensearch/common/document/DocumentField.java b/server/src/main/java/org/opensearch/common/document/DocumentField.java
index 9c6be10e5ea59..8ce672d4fb3fc 100644
--- a/server/src/main/java/org/opensearch/common/document/DocumentField.java
+++ b/server/src/main/java/org/opensearch/common/document/DocumentField.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common.document;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.search.SearchHit;
 
@@ -47,14 +47,16 @@
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.parseFieldsValue;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.parseFieldsValue;
 
 /**
  * A single field name and values part of {@link SearchHit} and {@link GetResult}.
  *
  * @see SearchHit
  * @see GetResult
+ *
+ * @opensearch.internal
  */
 public class DocumentField implements Writeable, ToXContentFragment, Iterable<Object> {
 
diff --git a/server/src/main/java/org/opensearch/common/document/package-info.java b/server/src/main/java/org/opensearch/common/document/package-info.java
new file mode 100644
index 0000000000000..8bd90082dfc17
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/document/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Document Level package. */
+package org.opensearch.common.document;
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoBoundingBox.java b/server/src/main/java/org/opensearch/common/geo/GeoBoundingBox.java
index 7413c27e63d23..60ed46435874b 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoBoundingBox.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoBoundingBox.java
@@ -32,13 +32,13 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.geometry.ShapeType;
@@ -52,6 +52,8 @@
 /**
  * A class representing a Geo-Bounding-Box for use by Geo queries and aggregations
  * that deal with extents/rectangles representing rectangular areas of interest.
+ *
+ * @opensearch.internal
  */
 public class GeoBoundingBox implements ToXContentObject, Writeable {
     private static final WellKnownText WKT_PARSER = new WellKnownText(true, new StandardValidator(true));
@@ -77,8 +79,8 @@ public GeoBoundingBox(GeoPoint topLeft, GeoPoint bottomRight) {
     }
 
     public GeoBoundingBox(StreamInput input) throws IOException {
-        this.topLeft = input.readGeoPoint();
-        this.bottomRight = input.readGeoPoint();
+        this.topLeft = new GeoPoint(input);
+        this.bottomRight = new GeoPoint(input);
     }
 
     public boolean isUnbounded() {
@@ -162,8 +164,8 @@ public boolean pointInBounds(double lon, double lat) {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeGeoPoint(topLeft);
-        out.writeGeoPoint(bottomRight);
+        topLeft.writeTo(out);
+        bottomRight.writeTo(out);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoDistance.java b/server/src/main/java/org/opensearch/common/geo/GeoDistance.java
index f21caaff4a058..37a03bcd237de 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoDistance.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoDistance.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.DistanceUnit;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 
 /**
  * Geo distance calculation.
+ *
+ * @opensearch.internal
  */
 public enum GeoDistance implements Writeable {
     PLANE,
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoJson.java b/server/src/main/java/org/opensearch/common/geo/GeoJson.java
index 529126c46241d..a3cbb4c121acd 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoJson.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoJson.java
@@ -34,16 +34,16 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.parsers.ShapeParser;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentSubParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentSubParser;
 import org.opensearch.geometry.Circle;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
@@ -66,8 +66,8 @@
 import java.util.Locale;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Utility class for converting libs/geo shapes to and from GeoJson
@@ -593,6 +593,11 @@ public String visit(Rectangle rectangle) {
         });
     }
 
+    /**
+     * A node for a geo coordinate
+     *
+     * @opensearch.internal
+     */
     private static class CoordinateNode implements ToXContentObject {
         public final Point coordinate;
         public final List<CoordinateNode> children;
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoJsonGeometryFormat.java b/server/src/main/java/org/opensearch/common/geo/GeoJsonGeometryFormat.java
index 26844d8b5c02a..0eeca04d670ef 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoJsonGeometryFormat.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoJsonGeometryFormat.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 
 import java.io.IOException;
 
+/**
+ * Geometry format for geojson
+ *
+ * @opensearch.internal
+ */
 public class GeoJsonGeometryFormat implements GeometryFormat<Geometry> {
     public static final String NAME = "geojson";
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoLineDecomposer.java b/server/src/main/java/org/opensearch/common/geo/GeoLineDecomposer.java
index dea59d042f3cb..e380e6a9e68d5 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoLineDecomposer.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoLineDecomposer.java
@@ -42,6 +42,8 @@
 
 /**
  * Splits lines by datelines.
+ *
+ * @opensearch.internal
  */
 public class GeoLineDecomposer {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoPoint.java b/server/src/main/java/org/opensearch/common/geo/GeoPoint.java
index a272228af5ab6..183d3a9f77b21 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoPoint.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoPoint.java
@@ -40,8 +40,10 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.geo.GeoUtils.EffectivePoint;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.Point;
 import org.opensearch.geometry.Rectangle;
@@ -56,6 +58,11 @@
 
 import static org.opensearch.index.mapper.AbstractPointGeometryFieldMapper.Names.IGNORE_Z_VALUE;
 
+/**
+ * Core geo point
+ *
+ * @opensearch.internal
+ */
 public class GeoPoint implements ToXContentFragment {
 
     protected double lat;
@@ -82,6 +89,11 @@ public GeoPoint(GeoPoint template) {
         this(template.getLat(), template.getLon());
     }
 
+    public GeoPoint(final StreamInput in) throws IOException {
+        this.lat = in.readDouble();
+        this.lon = in.readDouble();
+    }
+
     public GeoPoint reset(double lat, double lon) {
         this.lat = lat;
         this.lon = lon;
@@ -114,7 +126,11 @@ public GeoPoint resetFromString(String value, final boolean ignoreZValue, Effect
     public GeoPoint resetFromCoordinates(String value, final boolean ignoreZValue) {
         String[] vals = value.split(",");
         if (vals.length > 3) {
-            throw new OpenSearchParseException("failed to parse [{}], expected 2 or 3 coordinates " + "but found: [{}]", vals.length);
+            throw new OpenSearchParseException(
+                "failed to parse [{}], expected 2 or 3 coordinates " + "but found: [{}]",
+                value,
+                vals.length
+            );
         }
         final double lat;
         final double lon;
@@ -201,6 +217,11 @@ public GeoPoint resetFromGeoHash(long geohashLong) {
         return this.resetFromIndexHash(BitUtil.flipFlop((geohashLong >>> 4) << ((level * 5) + 2)));
     }
 
+    public void writeTo(final StreamOutput out) throws IOException {
+        out.writeDouble(this.lat);
+        out.writeDouble(this.lon);
+    }
+
     public double lat() {
         return this.lat;
     }
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoPolygonDecomposer.java b/server/src/main/java/org/opensearch/common/geo/GeoPolygonDecomposer.java
index 6577b10403fa2..2260f1ffdfeed 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoPolygonDecomposer.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoPolygonDecomposer.java
@@ -37,7 +37,6 @@
 import org.opensearch.geometry.MultiPolygon;
 import org.opensearch.geometry.Point;
 import org.opensearch.geometry.Polygon;
-import org.locationtech.spatial4j.exception.InvalidShapeException;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -49,12 +48,16 @@
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-import static org.apache.lucene.geo.GeoUtils.orient;
+import org.locationtech.spatial4j.exception.InvalidShapeException;
+
 import static org.opensearch.common.geo.GeoUtils.normalizeLat;
 import static org.opensearch.common.geo.GeoUtils.normalizeLon;
+import static org.apache.lucene.geo.GeoUtils.orient;
 
 /**
  * Splits polygons by datelines.
+ *
+ * @opensearch.internal
  */
 public class GeoPolygonDecomposer {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoShapeDocValue.java b/server/src/main/java/org/opensearch/common/geo/GeoShapeDocValue.java
new file mode 100644
index 0000000000000..0c6158598a423
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/geo/GeoShapeDocValue.java
@@ -0,0 +1,200 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.geo;
+
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.LatLonShape;
+import org.apache.lucene.document.LatLonShapeDocValues;
+import org.apache.lucene.document.LatLonShapeDocValuesField;
+import org.apache.lucene.geo.LatLonGeometry;
+import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.index.PointValues;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.GeometryVisitor;
+import org.opensearch.geometry.Rectangle;
+import org.opensearch.index.mapper.GeoShapeIndexer;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * This class is an OpenSearch Internal representation of lucene {@link LatLonShapeDocValuesField} for GeoShape.
+ *
+ * @opensearch.internal
+ */
+public class GeoShapeDocValue extends ShapeDocValue {
+    private static final String FIELD_NAME = "missingField";
+    private final LatLonShapeDocValues shapeDocValues;
+
+    public GeoShapeDocValue(final String fieldName, final BytesRef bytesRef) {
+        this(LatLonShape.createDocValueField(fieldName, bytesRef));
+    }
+
+    public GeoShapeDocValue(final LatLonShapeDocValuesField shapeDocValuesField) {
+        centroid = new Centroid(shapeDocValuesField.getCentroid().getLat(), shapeDocValuesField.getCentroid().getLon());
+        highestDimensionType = ShapeType.fromShapeFieldType(shapeDocValuesField.getHighestDimensionType());
+        boundingRectangle = new BoundingRectangle(
+            shapeDocValuesField.getBoundingBox().maxLon,
+            shapeDocValuesField.getBoundingBox().maxLat,
+            shapeDocValuesField.getBoundingBox().minLon,
+            shapeDocValuesField.getBoundingBox().minLat
+        );
+        this.shapeDocValues = LatLonShape.createLatLonShapeDocValues(shapeDocValuesField.binaryValue());
+    }
+
+    /**
+     * This function takes a {@link Geometry} and creates the {@link GeoShapeDocValue}. The function uses the
+     * {@link GeoShapeIndexer} to first convert the {@link Geometry} to {@link IndexableField}s and then convert it
+     * to the DocValue. This is very expensive function and should not be used on the Geometry Objects which are
+     * already converted to {@link IndexableField}s as it does the Tessellation internally which is already done on the
+     * {@link IndexableField}s.
+     *
+     * @param geometry {@link Geometry}
+     * @return {@link GeoShapeDocValue}
+     */
+    public static GeoShapeDocValue createGeometryDocValue(final Geometry geometry) {
+        // Setting the orientation to CCW, which will make the holes to CW. This is the default value which we will
+        // be using. This is in conjunction with what we take as a default value for geoshape in WKT format.
+        final GeoShapeIndexer shapeIndex = new GeoShapeIndexer(true, FIELD_NAME);
+        final List<IndexableField> indexableFields = shapeIndex.indexShape(null, shapeIndex.prepareForIndexing(geometry));
+        Field[] fieldsArray = new Field[indexableFields.size()];
+        fieldsArray = indexableFields.toArray(fieldsArray);
+        final LatLonShapeDocValuesField latLonShapeDocValuesField = LatLonShape.createDocValueField(FIELD_NAME, fieldsArray);
+        return new GeoShapeDocValue(latLonShapeDocValuesField);
+    }
+
+    public Centroid getCentroid() {
+        return (Centroid) centroid;
+    }
+
+    public BoundingRectangle getBoundingRectangle() {
+        return (BoundingRectangle) boundingRectangle;
+    }
+
+    @Override
+    public String toString() {
+        return "BoundingRectangle(" + boundingRectangle + "), Centroid(" + centroid + "), HighestDimension(" + highestDimensionType + ")";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        GeoShapeDocValue object = (GeoShapeDocValue) o;
+        boolean isEqual = true;
+        if (boundingRectangle != null) {
+            isEqual = boundingRectangle.equals(object.getBoundingRectangle());
+        }
+        if (centroid != null) {
+            isEqual = isEqual && centroid.equals(object.getCentroid());
+        }
+        if (highestDimensionType != null) {
+            isEqual = isEqual && highestDimensionType == object.getHighestDimensionType();
+        }
+        return isEqual;
+    }
+
+    @Override
+    public int hashCode() {
+        int result;
+        long temp;
+        temp = boundingRectangle != null ? boundingRectangle.hashCode() : 0L;
+        result = Long.hashCode(temp);
+        temp = centroid != null ? centroid.hashCode() : 0L;
+        result = 31 * result + Long.hashCode(temp);
+        temp = highestDimensionType != null ? highestDimensionType.hashCode() : 0L;
+
+        result = 31 * result + Long.hashCode(temp);
+        return result;
+    }
+
+    /**
+     * An extension for {@link ShapeDocValue.Centroid} which make easy to read the values when centroid is on the
+     * EarthSurface
+     */
+    public static final class Centroid extends ShapeDocValue.Centroid {
+
+        Centroid(final double lat, final double lon) {
+            super(lat, lon);
+        }
+
+        public double getLatitude() {
+            return getY();
+        }
+
+        public double getLongitude() {
+            return getX();
+        }
+
+        @Override
+        public String toString() {
+            return getY() + ", " + getX();
+        }
+
+    }
+
+    /**
+     * An extension for {@link ShapeDocValue.BoundingRectangle} which make easy to read the values when BB is on the
+     * EarthSurface
+     */
+    public static final class BoundingRectangle extends ShapeDocValue.BoundingRectangle {
+
+        BoundingRectangle(final double maxLon, final double maxLat, final double minLon, final double minLat) {
+            super(maxLon, maxLat, minLon, minLat);
+        }
+
+        public double getMaxLongitude() {
+            return getMaxX();
+        }
+
+        public double getMaxLatitude() {
+            return getMaxY();
+        }
+
+        public double getMinLatitude() {
+            return getMinY();
+        }
+
+        public double getMinLongitude() {
+            return getMinX();
+        }
+
+        @Override
+        public String toString() {
+            return "maxLatitude: "
+                + getMaxY()
+                + ", minLatitude: "
+                + getMinY()
+                + ", maxLongitude: "
+                + getMaxX()
+                + ", minLongitude: "
+                + getMinX();
+
+        }
+    }
+
+    /**
+     * Checks if the input {@link Rectangle} is intersecting with the shape represented as {@link GeoShapeDocValue}.
+     * We could have used the {@link GeometryVisitor} here and added the functionality to check the intersection with
+     * other {@link Geometry} also, but that will be an overkill for now, if required we can easily create a
+     * {@link GeometryVisitor} to check the intersection with this Shape represented as {@link GeoShapeDocValue}.
+     * @return boolean
+     */
+    public boolean isIntersectingRectangle(final Rectangle rectangle) {
+        final org.apache.lucene.geo.Rectangle luceneRectangle = GeoShapeUtils.toLuceneRectangle(rectangle);
+        try {
+            final PointValues.Relation relation = shapeDocValues.relate(LatLonGeometry.create(luceneRectangle));
+            return relation != PointValues.Relation.CELL_OUTSIDE_QUERY;
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoShapeType.java b/server/src/main/java/org/opensearch/common/geo/GeoShapeType.java
index 7b2e90d8ed62b..0334d367ffdbc 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoShapeType.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoShapeType.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.common.geo;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.geo.builders.CircleBuilder;
 import org.opensearch.common.geo.builders.CoordinatesBuilder;
@@ -46,8 +45,8 @@
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder.Orientation;
 import org.opensearch.common.geo.parsers.CoordinateNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
 import org.opensearch.common.unit.DistanceUnit;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -55,8 +54,12 @@
 import java.util.Locale;
 import java.util.Map;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * Enumeration that lists all {@link GeoShapeType}s that can be parsed and indexed
+ *
+ * @opensearch.internal
  */
 public enum GeoShapeType {
     POINT("point") {
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoShapeUtils.java b/server/src/main/java/org/opensearch/common/geo/GeoShapeUtils.java
index ac248f6bb6dcc..7a59c7a08014b 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoShapeUtils.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoShapeUtils.java
@@ -39,6 +39,8 @@
 
 /**
  * Utility class that transforms OpenSearch geometry objects to the Lucene representation
+ *
+ * @opensearch.internal
  */
 public class GeoShapeUtils {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeoUtils.java b/server/src/main/java/org/opensearch/common/geo/GeoUtils.java
index 1585e6cf2ad60..393c238cb3b2f 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeoUtils.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeoUtils.java
@@ -38,12 +38,12 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
-import org.opensearch.common.xcontent.XContentSubParser;
-import org.opensearch.common.xcontent.support.MapXContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentSubParser;
+import org.opensearch.geometry.ShapeType;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.GeoPointValues;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
@@ -53,9 +53,16 @@
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.HashMap;
 
+/**
+ * Useful geo utilities
+ *
+ * @opensearch.internal
+ */
 public class GeoUtils {
-
+    private static final String ERR_MSG_INVALID_TOKEN = "token [{}] not allowed";
+    private static final String ERR_MSG_INVALID_FIELDS = "field must be either [lon|lat], [type|coordinates], or [geohash]";
     /** Maximum valid latitude in degrees. */
     public static final double MAX_LAT = 90.0;
     /** Minimum valid latitude in degrees. */
@@ -69,6 +76,8 @@ public class GeoUtils {
     public static final String LONGITUDE = "lon";
     public static final String GEOHASH = "geohash";
 
+    public static final String GEOJSON_TYPE = "type";
+    public static final String GEOJSON_COORDS = "coordinates";
     /** Earth ellipsoid major axis defined by WGS 84 in meters */
     public static final double EARTH_SEMI_MAJOR_AXIS = 6378137.0;      // meters (WGS 84)
 
@@ -416,6 +425,8 @@ public static GeoPoint parseGeoPoint(Object value, GeoPoint point, final boolean
 
     /**
      * Represents the point of the geohash cell that should be used as the value of geohash
+     *
+     * @opensearch.internal
      */
     public enum EffectivePoint {
         TOP_LEFT,
@@ -437,112 +448,202 @@ public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, fina
      * Parse a {@link GeoPoint} with a {@link XContentParser}. A geopoint has one of the following forms:
      *
      * <ul>
-     *     <li>Object: <pre>{&quot;lat&quot;: <i>&lt;latitude&gt;</i>, &quot;lon&quot;: <i>&lt;longitude&gt;</i>}</pre></li>
-     *     <li>String: <pre>&quot;<i>&lt;latitude&gt;</i>,<i>&lt;longitude&gt;</i>&quot;</pre></li>
-     *     <li>Geohash: <pre>&quot;<i>&lt;geohash&gt;</i>&quot;</pre></li>
-     *     <li>Array: <pre>[<i>&lt;longitude&gt;</i>,<i>&lt;latitude&gt;</i>]</pre></li>
+     *     <li>Object: <pre>{@code {"lat": <latitude>, "lon": <longitude}}</pre></li>
+     *     <li>String: <pre>{@code "<latitude>,<longitude>"}</pre></li>
+     *     <li>GeoHash: <pre>{@code "<geohash>"}</pre></li>
+     *     <li>WKT: <pre>{@code "POINT (<longitude> <latitude>)"}</pre></li>
+     *     <li>Array: <pre>{@code [<longitude>, <latitude>]}</pre></li>
+     *     <li>GeoJson: <pre>{@code {"type": "Point", "coordinates": [<longitude>, <latitude>]}}</pre><li>
      * </ul>
      *
+     *
      * @param parser {@link XContentParser} to parse the value from
      * @param point A {@link GeoPoint} that will be reset by the values parsed
+     * @param ignoreZValue tells to ignore z value or throw exception when there is a z value
+     * @param effectivePoint tells which point to use for GeoHash form
      * @return new {@link GeoPoint} parsed from the parse
      */
-    public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, final boolean ignoreZValue, EffectivePoint effectivePoint)
-        throws IOException, OpenSearchParseException {
-        double lat = Double.NaN;
-        double lon = Double.NaN;
-        String geohash = null;
-        NumberFormatException numberFormatException = null;
-
-        if (parser.currentToken() == Token.START_OBJECT) {
-            try (XContentSubParser subParser = new XContentSubParser(parser)) {
-                while (subParser.nextToken() != Token.END_OBJECT) {
-                    if (subParser.currentToken() == Token.FIELD_NAME) {
-                        String field = subParser.currentName();
-                        if (LATITUDE.equals(field)) {
-                            subParser.nextToken();
-                            switch (subParser.currentToken()) {
-                                case VALUE_NUMBER:
-                                case VALUE_STRING:
-                                    try {
-                                        lat = subParser.doubleValue(true);
-                                    } catch (NumberFormatException e) {
-                                        numberFormatException = e;
-                                    }
-                                    break;
-                                default:
-                                    throw new OpenSearchParseException("latitude must be a number");
-                            }
-                        } else if (LONGITUDE.equals(field)) {
-                            subParser.nextToken();
-                            switch (subParser.currentToken()) {
-                                case VALUE_NUMBER:
-                                case VALUE_STRING:
-                                    try {
-                                        lon = subParser.doubleValue(true);
-                                    } catch (NumberFormatException e) {
-                                        numberFormatException = e;
-                                    }
-                                    break;
-                                default:
-                                    throw new OpenSearchParseException("longitude must be a number");
-                            }
-                        } else if (GEOHASH.equals(field)) {
-                            if (subParser.nextToken() == Token.VALUE_STRING) {
-                                geohash = subParser.text();
-                            } else {
-                                throw new OpenSearchParseException("geohash must be a string");
-                            }
-                        } else {
-                            throw new OpenSearchParseException("field must be either [{}], [{}] or [{}]", LATITUDE, LONGITUDE, GEOHASH);
-                        }
-                    } else {
-                        throw new OpenSearchParseException("token [{}] not allowed", subParser.currentToken());
+    public static GeoPoint parseGeoPoint(
+        final XContentParser parser,
+        final GeoPoint point,
+        final boolean ignoreZValue,
+        final EffectivePoint effectivePoint
+    ) throws IOException, OpenSearchParseException {
+        switch (parser.currentToken()) {
+            case START_OBJECT:
+                parseGeoPointObject(parser, point, ignoreZValue, effectivePoint);
+                break;
+            case START_ARRAY:
+                parseGeoPointArray(parser, point, ignoreZValue);
+                break;
+            case VALUE_STRING:
+                String val = parser.text();
+                point.resetFromString(val, ignoreZValue, effectivePoint);
+                break;
+            default:
+                throw new OpenSearchParseException("geo_point expected");
+        }
+        return point;
+    }
+
+    private static GeoPoint parseGeoPointObject(
+        final XContentParser parser,
+        final GeoPoint point,
+        final boolean ignoreZValue,
+        final GeoUtils.EffectivePoint effectivePoint
+    ) throws IOException {
+        try (XContentSubParser subParser = new XContentSubParser(parser)) {
+            if (subParser.nextToken() != XContentParser.Token.FIELD_NAME) {
+                throw new OpenSearchParseException(ERR_MSG_INVALID_TOKEN, subParser.currentToken());
+            }
+
+            String field = subParser.currentName();
+            if (LONGITUDE.equals(field) || LATITUDE.equals(field)) {
+                parseGeoPointObjectBasicFields(subParser, point);
+            } else if (GEOHASH.equals(field)) {
+                parseGeoHashFields(subParser, point, effectivePoint);
+            } else if (GEOJSON_TYPE.equals(field) || GEOJSON_COORDS.equals(field)) {
+                parseGeoJsonFields(subParser, point, ignoreZValue);
+            } else {
+                throw new OpenSearchParseException(ERR_MSG_INVALID_FIELDS);
+            }
+
+            if (subParser.nextToken() != XContentParser.Token.END_OBJECT) {
+                throw new OpenSearchParseException(ERR_MSG_INVALID_FIELDS);
+            }
+
+            return point;
+        }
+    }
+
+    private static GeoPoint parseGeoPointObjectBasicFields(final XContentParser parser, final GeoPoint point) throws IOException {
+        HashMap<String, Double> data = new HashMap<>();
+        for (int i = 0; i < 2; i++) {
+            if (i != 0) {
+                parser.nextToken();
+            }
+
+            if (parser.currentToken() != XContentParser.Token.FIELD_NAME) {
+                break;
+            }
+
+            String field = parser.currentName();
+            if (LONGITUDE.equals(field) == false && LATITUDE.equals(field) == false) {
+                throw new OpenSearchParseException(ERR_MSG_INVALID_FIELDS);
+            }
+            switch (parser.nextToken()) {
+                case VALUE_NUMBER:
+                case VALUE_STRING:
+                    try {
+                        data.put(field, parser.doubleValue(true));
+                    } catch (NumberFormatException e) {
+                        throw new OpenSearchParseException("[{}] and [{}] must be valid double values", e, LONGITUDE, LATITUDE);
                     }
+                    break;
+                default:
+                    throw new OpenSearchParseException("{} must be a number", field);
+            }
+        }
+
+        if (data.get(LONGITUDE) == null) {
+            throw new OpenSearchParseException("field [{}] missing", LONGITUDE);
+        }
+        if (data.get(LATITUDE) == null) {
+            throw new OpenSearchParseException("field [{}] missing", LATITUDE);
+        }
+
+        return point.reset(data.get(LATITUDE), data.get(LONGITUDE));
+    }
+
+    private static GeoPoint parseGeoHashFields(
+        final XContentParser parser,
+        final GeoPoint point,
+        final GeoUtils.EffectivePoint effectivePoint
+    ) throws IOException {
+        if (parser.currentToken() != XContentParser.Token.FIELD_NAME) {
+            throw new OpenSearchParseException(ERR_MSG_INVALID_TOKEN, parser.currentToken());
+        }
+
+        if (GEOHASH.equals(parser.currentName()) == false) {
+            throw new OpenSearchParseException(ERR_MSG_INVALID_FIELDS);
+        }
+
+        if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+            throw new OpenSearchParseException("{} must be a string", GEOHASH);
+        }
+
+        return point.parseGeoHash(parser.text(), effectivePoint);
+    }
+
+    private static GeoPoint parseGeoJsonFields(final XContentParser parser, final GeoPoint point, final boolean ignoreZValue)
+        throws IOException {
+        boolean hasTypePoint = false;
+        boolean hasCoordinates = false;
+        for (int i = 0; i < 2; i++) {
+            if (i != 0) {
+                parser.nextToken();
+            }
+
+            if (parser.currentToken() != XContentParser.Token.FIELD_NAME) {
+                if (hasTypePoint == false) {
+                    throw new OpenSearchParseException("field [{}] missing", GEOJSON_TYPE);
+                }
+                if (hasCoordinates == false) {
+                    throw new OpenSearchParseException("field [{}] missing", GEOJSON_COORDS);
                 }
             }
-            if (geohash != null) {
-                if (!Double.isNaN(lat) || !Double.isNaN(lon)) {
-                    throw new OpenSearchParseException("field must be either lat/lon or geohash");
-                } else {
-                    return point.parseGeoHash(geohash, effectivePoint);
+
+            if (GEOJSON_TYPE.equals(parser.currentName())) {
+                if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                    throw new OpenSearchParseException("{} must be a string", GEOJSON_TYPE);
                 }
-            } else if (numberFormatException != null) {
-                throw new OpenSearchParseException("[{}] and [{}] must be valid double values", numberFormatException, LATITUDE, LONGITUDE);
-            } else if (Double.isNaN(lat)) {
-                throw new OpenSearchParseException("field [{}] missing", LATITUDE);
-            } else if (Double.isNaN(lon)) {
-                throw new OpenSearchParseException("field [{}] missing", LONGITUDE);
+
+                // To be consistent with geo_shape parsing, ignore case here as well.
+                if (ShapeType.POINT.name().equalsIgnoreCase(parser.text()) == false) {
+                    throw new OpenSearchParseException("{} must be Point", GEOJSON_TYPE);
+                }
+                hasTypePoint = true;
+            } else if (GEOJSON_COORDS.equals(parser.currentName())) {
+                if (parser.nextToken() != XContentParser.Token.START_ARRAY) {
+                    throw new OpenSearchParseException("{} must be an array", GEOJSON_COORDS);
+                }
+                parseGeoPointArray(parser, point, ignoreZValue);
+                hasCoordinates = true;
             } else {
-                return point.reset(lat, lon);
+                throw new OpenSearchParseException(ERR_MSG_INVALID_FIELDS);
             }
+        }
 
-        } else if (parser.currentToken() == Token.START_ARRAY) {
-            try (XContentSubParser subParser = new XContentSubParser(parser)) {
-                int element = 0;
-                while (subParser.nextToken() != Token.END_ARRAY) {
-                    if (subParser.currentToken() == Token.VALUE_NUMBER) {
-                        element++;
-                        if (element == 1) {
-                            lon = subParser.doubleValue();
-                        } else if (element == 2) {
-                            lat = subParser.doubleValue();
-                        } else if (element == 3) {
-                            GeoPoint.assertZValue(ignoreZValue, subParser.doubleValue());
-                        } else {
-                            throw new OpenSearchParseException("[geo_point] field type does not accept > 3 dimensions");
-                        }
-                    } else {
-                        throw new OpenSearchParseException("numeric value expected");
-                    }
+        return point;
+    }
+
+    private static GeoPoint parseGeoPointArray(final XContentParser parser, final GeoPoint point, final boolean ignoreZValue)
+        throws IOException {
+        try (XContentSubParser subParser = new XContentSubParser(parser)) {
+            double x = Double.NaN;
+            double y = Double.NaN;
+
+            int element = 0;
+            while (subParser.nextToken() != XContentParser.Token.END_ARRAY) {
+                if (parser.currentToken() != XContentParser.Token.VALUE_NUMBER) {
+                    throw new OpenSearchParseException("numeric value expected");
+                }
+                element++;
+                if (element == 1) {
+                    x = parser.doubleValue();
+                } else if (element == 2) {
+                    y = parser.doubleValue();
+                } else if (element == 3) {
+                    GeoPoint.assertZValue(ignoreZValue, parser.doubleValue());
+                } else {
+                    throw new OpenSearchParseException("[geo_point] field type does not accept more than 3 values");
                 }
             }
-            return point.reset(lat, lon);
-        } else if (parser.currentToken() == Token.VALUE_STRING) {
-            String val = parser.text();
-            return point.resetFromString(val, ignoreZValue, effectivePoint);
-        } else {
-            throw new OpenSearchParseException("geo_point expected");
+
+            if (element < 2) {
+                throw new OpenSearchParseException("[geo_point] field type should have at least two dimensions");
+            }
+            return point.reset(y, x);
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeometryFormat.java b/server/src/main/java/org/opensearch/common/geo/GeometryFormat.java
index c907ee722c1ae..56146fc8197be 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeometryFormat.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeometryFormat.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.text.ParseException;
 
 /**
  * Geometry serializer/deserializer
+ *
+ * @opensearch.internal
  */
 public interface GeometryFormat<ParsedFormat> {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeometryIO.java b/server/src/main/java/org/opensearch/common/geo/GeometryIO.java
index 113e7a6e9fa0e..83f7fd581fac3 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeometryIO.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeometryIO.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.DistanceUnit;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.geometry.Circle;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
@@ -55,6 +55,8 @@
 
 /**
  * Utility class for binary serializtion/deserialization of libs/geo classes
+ *
+ * @opensearch.internal
  */
 public final class GeometryIO {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/GeometryParser.java b/server/src/main/java/org/opensearch/common/geo/GeometryParser.java
index f1fc1f9a1b1d0..ecd1fa9e3acce 100644
--- a/server/src/main/java/org/opensearch/common/geo/GeometryParser.java
+++ b/server/src/main/java/org/opensearch/common/geo/GeometryParser.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.support.MapXContentParser;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
 import org.opensearch.geometry.Point;
@@ -53,6 +53,8 @@
 
 /**
  * An utility class with a geometry parser methods supporting different shape representation formats
+ *
+ * @opensearch.internal
  */
 public final class GeometryParser {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/ShapeDocValue.java b/server/src/main/java/org/opensearch/common/geo/ShapeDocValue.java
new file mode 100644
index 0000000000000..068cab91e53d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/geo/ShapeDocValue.java
@@ -0,0 +1,188 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.geo;
+
+import org.apache.lucene.document.ShapeField;
+import org.apache.lucene.document.XYShapeDocValuesField;
+
+import java.util.Arrays;
+import java.util.Locale;
+
+/**
+ * This class is an OpenSearch Internal representation of lucene {@link XYShapeDocValuesField} for GeoShape.
+ *
+ * @opensearch.internal
+ */
+public class ShapeDocValue {
+    protected Centroid centroid;
+    protected BoundingRectangle boundingRectangle;
+    protected ShapeType highestDimensionType;
+
+    public Centroid getCentroid() {
+        return centroid;
+    }
+
+    public BoundingRectangle getBoundingRectangle() {
+        return boundingRectangle;
+    }
+
+    public ShapeType getHighestDimensionType() {
+        return highestDimensionType;
+    }
+
+    /**
+     * Provides the centroid of the field(Shape) which has been indexed.
+     */
+    public static class Centroid {
+        private final double y;
+        private final double x;
+
+        Centroid(final double y, final double x) {
+            this.y = y;
+            this.x = x;
+        }
+
+        public double getY() {
+            return y;
+        }
+
+        public double getX() {
+            return x;
+        }
+
+        @Override
+        public String toString() {
+            return y + ", " + x;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+
+            Centroid centroid = (Centroid) o;
+
+            if (Double.compare(centroid.y, y) != 0) return false;
+            if (Double.compare(centroid.x, x) != 0) return false;
+            return true;
+        }
+
+        @Override
+        public int hashCode() {
+            int result;
+            long temp;
+            temp = y != +0.0d ? Double.doubleToLongBits(y) : 0L;
+            result = Long.hashCode(temp);
+            temp = x != +0.0d ? Double.doubleToLongBits(x) : 0L;
+            result = 31 * result + Long.hashCode(temp);
+            return result;
+        }
+    }
+
+    /**
+     * Provides the BoundingBox of the field(Shape) which has been indexed.
+     */
+    public static class BoundingRectangle {
+        private final double maxX, maxY, minY, minX;
+
+        BoundingRectangle(final double maxLon, final double maxLat, final double minLon, final double minLat) {
+            maxY = maxLat;
+            maxX = maxLon;
+            minY = minLat;
+            minX = minLon;
+        }
+
+        public double getMaxX() {
+            return maxX;
+        }
+
+        public double getMaxY() {
+            return maxY;
+        }
+
+        public double getMinY() {
+            return minY;
+        }
+
+        public double getMinX() {
+            return minX;
+        }
+
+        @Override
+        public String toString() {
+            return "maxY: " + maxY + "minY: " + minY + "maxX: " + maxX + "minX: " + minX;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+
+            BoundingRectangle boundingRectangle = (BoundingRectangle) o;
+
+            if (Double.compare(boundingRectangle.maxY, maxY) != 0) return false;
+            if (Double.compare(boundingRectangle.maxX, minX) != 0) return false;
+            if (Double.compare(boundingRectangle.minY, minY) != 0) return false;
+            if (Double.compare(boundingRectangle.minX, minX) != 0) return false;
+            return true;
+        }
+
+        @Override
+        public int hashCode() {
+            int result;
+            long temp;
+            temp = maxY != +0.0d ? Double.doubleToLongBits(maxY) : 0L;
+            result = Long.hashCode(temp);
+
+            temp = maxX != +0.0d ? Double.doubleToLongBits(maxX) : 0L;
+            result = 31 * result + Long.hashCode(temp);
+
+            temp = minY != +0.0d ? Double.doubleToLongBits(minY) : 0L;
+            result = 31 * result + Long.hashCode(temp);
+
+            temp = minX != +0.0d ? Double.doubleToLongBits(minX) : 0L;
+            result = 31 * result + Long.hashCode(temp);
+
+            return result;
+        }
+    }
+
+    /**
+     * An Enum class defining the highest type of Geometry present in this doc value.
+     */
+    public enum ShapeType {
+        POINT,
+        LINE,
+        TRIANGLE;
+
+        public static ShapeType fromShapeFieldType(final ShapeField.DecodedTriangle.TYPE type) {
+            switch (type) {
+                case POINT:
+                    return POINT;
+                case LINE:
+                    return LINE;
+                case TRIANGLE:
+                    return TRIANGLE;
+            }
+            throw new IllegalStateException(
+                String.format(
+                    Locale.ROOT,
+                    "No correct mapped type found for the value %s in the list of values : %s",
+                    type,
+                    Arrays.toString(ShapeType.values())
+                )
+            );
+        }
+
+        @Override
+        public String toString() {
+            return name();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/geo/ShapeRelation.java b/server/src/main/java/org/opensearch/common/geo/ShapeRelation.java
index 96ffe19129db9..0a5a66ef54c9c 100644
--- a/server/src/main/java/org/opensearch/common/geo/ShapeRelation.java
+++ b/server/src/main/java/org/opensearch/common/geo/ShapeRelation.java
@@ -33,9 +33,9 @@
 package org.opensearch.common.geo;
 
 import org.apache.lucene.document.ShapeField.QueryRelation;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -43,6 +43,8 @@
 /**
  * Enum representing the relationship between a Query / Filter Shape and indexed Shapes
  * that will be used to determine if a Document should be matched or not
+ *
+ * @opensearch.internal
  */
 public enum ShapeRelation implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/ShapesAvailability.java b/server/src/main/java/org/opensearch/common/geo/ShapesAvailability.java
index f1a9638e998ff..abf7e7effb464 100644
--- a/server/src/main/java/org/opensearch/common/geo/ShapesAvailability.java
+++ b/server/src/main/java/org/opensearch/common/geo/ShapesAvailability.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.geo;
 
+/**
+ * Checks if certain geometry packages are available
+ *
+ * @opensearch.internal
+ */
 public class ShapesAvailability {
 
     public static final boolean SPATIAL4J_AVAILABLE;
diff --git a/server/src/main/java/org/opensearch/common/geo/SpatialStrategy.java b/server/src/main/java/org/opensearch/common/geo/SpatialStrategy.java
index 5eda2471e73fe..c1a13b289c6e5 100644
--- a/server/src/main/java/org/opensearch/common/geo/SpatialStrategy.java
+++ b/server/src/main/java/org/opensearch/common/geo/SpatialStrategy.java
@@ -31,12 +31,20 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Spatial strategy for legacy prefix trees
+ *
+ * @deprecated will be removed in future version
+ *
+ * @opensearch.internal
+ */
+@Deprecated
 public enum SpatialStrategy implements Writeable {
 
     TERM("term"),
diff --git a/server/src/main/java/org/opensearch/common/geo/WKTGeometryFormat.java b/server/src/main/java/org/opensearch/common/geo/WKTGeometryFormat.java
index 84d12d2ebb5ab..699981cb8be69 100644
--- a/server/src/main/java/org/opensearch/common/geo/WKTGeometryFormat.java
+++ b/server/src/main/java/org/opensearch/common/geo/WKTGeometryFormat.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.utils.WellKnownText;
 
 import java.io.IOException;
 import java.text.ParseException;
 
+/**
+ * Well Known Text Format
+ *
+ * @opensearch.internal
+ */
 public class WKTGeometryFormat implements GeometryFormat<Geometry> {
     public static final String NAME = "wkt";
 
diff --git a/server/src/main/java/org/opensearch/common/geo/XShapeCollection.java b/server/src/main/java/org/opensearch/common/geo/XShapeCollection.java
index e505a804e790e..2957236e9525c 100644
--- a/server/src/main/java/org/opensearch/common/geo/XShapeCollection.java
+++ b/server/src/main/java/org/opensearch/common/geo/XShapeCollection.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.common.geo;
 
+import java.util.List;
+
 import org.locationtech.spatial4j.context.SpatialContext;
 import org.locationtech.spatial4j.shape.Shape;
 import org.locationtech.spatial4j.shape.ShapeCollection;
 
-import java.util.List;
-
 /**
  * Extends spatial4j ShapeCollection for points_only shape indexing support
+ *
+ * @opensearch.internal
  */
 public class XShapeCollection<S extends Shape> extends ShapeCollection<S> {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/CircleBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/CircleBuilder.java
index fb773ed6654d3..689ae1f291e51 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/CircleBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/CircleBuilder.java
@@ -32,21 +32,26 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.locationtech.spatial4j.shape.Circle;
-import org.locationtech.jts.geom.Coordinate;
-
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.common.unit.DistanceUnit.Distance;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Circle;
+
+/**
+ * Builds a circle geometry
+ *
+ * @opensearch.internal
+ */
 public class CircleBuilder extends ShapeBuilder<Circle, org.opensearch.geometry.Circle, CircleBuilder> {
 
     public static final ParseField FIELD_RADIUS = new ParseField("radius");
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/CoordinatesBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/CoordinatesBuilder.java
index 9c727830623da..ab238230b06ce 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/CoordinatesBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/CoordinatesBuilder.java
@@ -33,17 +33,20 @@
 package org.opensearch.common.geo.builders;
 
 import org.opensearch.OpenSearchException;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * A builder for a list of coordinates.
  * Enables chaining of individual coordinates either as long/lat pairs
  * or as {@link Coordinate} elements, arrays or collections.
+ *
+ * @opensearch.internal
  */
 public class CoordinatesBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/EnvelopeBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/EnvelopeBuilder.java
index 5513d9912b92c..cc09eed913d6b 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/EnvelopeBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/EnvelopeBuilder.java
@@ -35,16 +35,21 @@
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.GeoWKTParser;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.locationtech.spatial4j.shape.Rectangle;
-import org.locationtech.jts.geom.Coordinate;
-
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Rectangle;
+
+/**
+ * Builds an envelope geometry
+ *
+ * @opensearch.internal
+ */
 public class EnvelopeBuilder extends ShapeBuilder<Rectangle, org.opensearch.geometry.Rectangle, EnvelopeBuilder> {
 
     public static final GeoShapeType TYPE = GeoShapeType.ENVELOPE;
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/GeometryCollectionBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/GeometryCollectionBuilder.java
index 09fec96e0e693..cbfb1a3521116 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/GeometryCollectionBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/GeometryCollectionBuilder.java
@@ -37,18 +37,24 @@
 import org.opensearch.common.geo.XShapeCollection;
 import org.opensearch.common.geo.parsers.GeoWKTParser;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
-import org.locationtech.spatial4j.shape.Shape;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
+import org.locationtech.spatial4j.shape.Shape;
+
+/**
+ * Builds a geometry collection
+ *
+ * @opensearch.internal
+ */
 public class GeometryCollectionBuilder extends ShapeBuilder<Shape, GeometryCollection<Geometry>, GeometryCollectionBuilder> {
 
     public static final GeoShapeType TYPE = GeoShapeType.GEOMETRYCOLLECTION;
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/LineStringBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/LineStringBuilder.java
index ae7075ff7bb47..dacf8056cfe2e 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/LineStringBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/LineStringBuilder.java
@@ -34,20 +34,26 @@
 
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Line;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.jts.geom.Geometry;
-import org.locationtech.jts.geom.GeometryFactory;
-import org.locationtech.jts.geom.LineString;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
+/**
+ * Builds a line string geometry
+ *
+ * @opensearch.internal
+ */
 public class LineStringBuilder extends ShapeBuilder<JtsGeometry, org.opensearch.geometry.Geometry, LineStringBuilder> {
     public static final GeoShapeType TYPE = GeoShapeType.LINESTRING;
 
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/MultiLineStringBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/MultiLineStringBuilder.java
index 9e303b8de2a6e..db5bd758b715c 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/MultiLineStringBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/MultiLineStringBuilder.java
@@ -35,15 +35,11 @@
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.GeoWKTParser;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Line;
 import org.opensearch.geometry.MultiLine;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.jts.geom.Geometry;
-import org.locationtech.jts.geom.LineString;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -51,6 +47,16 @@
 import java.util.List;
 import java.util.Objects;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
+/**
+ * Builds a multi line string geometry
+ *
+ * @opensearch.internal
+ */
 public class MultiLineStringBuilder extends ShapeBuilder<JtsGeometry, org.opensearch.geometry.Geometry, MultiLineStringBuilder> {
 
     public static final GeoShapeType TYPE = GeoShapeType.MULTILINESTRING;
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/MultiPointBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/MultiPointBuilder.java
index 29ec72f4755be..0bfa91e013bd6 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/MultiPointBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/MultiPointBuilder.java
@@ -35,17 +35,23 @@
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.XShapeCollection;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.MultiPoint;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.Point;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Point;
+
+/**
+ * Builds a multi point geometry
+ *
+ * @opensearch.internal
+ */
 public class MultiPointBuilder extends ShapeBuilder<XShapeCollection<Point>, MultiPoint, MultiPointBuilder> {
 
     public static final GeoShapeType TYPE = GeoShapeType.MULTIPOINT;
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/MultiPolygonBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/MultiPolygonBuilder.java
index ac78c09c91b48..102909f93bec4 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/MultiPolygonBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/MultiPolygonBuilder.java
@@ -36,13 +36,11 @@
 import org.opensearch.common.geo.XShapeCollection;
 import org.opensearch.common.geo.parsers.GeoWKTParser;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.MultiPolygon;
 import org.opensearch.geometry.Polygon;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.Shape;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -50,6 +48,14 @@
 import java.util.Locale;
 import java.util.Objects;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Shape;
+
+/**
+ * Builds a multi polygon geometry
+ *
+ * @opensearch.internal
+ */
 public class MultiPolygonBuilder extends ShapeBuilder<Shape, MultiPolygon, MultiPolygonBuilder> {
 
     public static final GeoShapeType TYPE = GeoShapeType.MULTIPOLYGON;
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/PointBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/PointBuilder.java
index 86878f736d6e6..6f68546fea368 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/PointBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/PointBuilder.java
@@ -34,13 +34,19 @@
 
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.Point;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Point;
+
+/**
+ * Builds a point geometry
+ *
+ * @opensearch.internal
+ */
 public class PointBuilder extends ShapeBuilder<Point, org.opensearch.geometry.Point, PointBuilder> {
     public static final GeoShapeType TYPE = GeoShapeType.POINT;
 
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/PolygonBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/PolygonBuilder.java
index 5abc01e5aade6..8e65352142e69 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/PolygonBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/PolygonBuilder.java
@@ -35,18 +35,10 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.jts.geom.Geometry;
-import org.locationtech.jts.geom.GeometryFactory;
-import org.locationtech.jts.geom.LinearRing;
-import org.locationtech.jts.geom.MultiPolygon;
-import org.locationtech.jts.geom.Polygon;
-import org.locationtech.spatial4j.exception.InvalidShapeException;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -59,12 +51,23 @@
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.jts.geom.LinearRing;
+import org.locationtech.jts.geom.MultiPolygon;
+import org.locationtech.jts.geom.Polygon;
+import org.locationtech.spatial4j.exception.InvalidShapeException;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
 import static org.apache.lucene.geo.GeoUtils.orient;
 
 /**
  * The {@link PolygonBuilder} implements the groundwork to create polygons. This contains
  * Methods to wrap polygons at the dateline and building shapes from the data held by the
  * builder.
+ *
+ * @opensearch.internal
  */
 public class PolygonBuilder extends ShapeBuilder<JtsGeometry, org.opensearch.geometry.Geometry, PolygonBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/ShapeBuilder.java b/server/src/main/java/org/opensearch/common/geo/builders/ShapeBuilder.java
index afd57ad6ab5f3..b3513a83858df 100644
--- a/server/src/main/java/org/opensearch/common/geo/builders/ShapeBuilder.java
+++ b/server/src/main/java/org/opensearch/common/geo/builders/ShapeBuilder.java
@@ -32,25 +32,18 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.jts.geom.Geometry;
-import org.locationtech.jts.geom.GeometryFactory;
-
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.Assertions;
-import org.opensearch.common.Strings;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.GeoWKTParser;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.locationtech.spatial4j.context.jts.JtsSpatialContext;
-import org.locationtech.spatial4j.exception.InvalidShapeException;
-import org.locationtech.spatial4j.shape.Shape;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -61,8 +54,18 @@
 import java.util.Locale;
 import java.util.Objects;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.spatial4j.context.jts.JtsSpatialContext;
+import org.locationtech.spatial4j.exception.InvalidShapeException;
+import org.locationtech.spatial4j.shape.Shape;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
 /**
  * Basic class for building GeoJSON shapes like Polygons, Linestrings, etc
+ *
+ * @opensearch.internal
  */
 public abstract class ShapeBuilder<T extends Shape, G extends org.opensearch.geometry.Geometry, E extends ShapeBuilder<T, G, E>>
     implements
@@ -418,6 +421,11 @@ public int compare(Edge o1, Edge o2) {
         }
     }
 
+    /**
+     * The orientation of the vertices
+     *
+     * @opensearch.internal
+     */
     public enum Orientation {
         LEFT,
         RIGHT;
@@ -513,6 +521,6 @@ public String getWriteableName() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/common/geo/builders/package-info.java b/server/src/main/java/org/opensearch/common/geo/builders/package-info.java
new file mode 100644
index 0000000000000..bb4f9105835be
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/geo/builders/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Geo Builders package. */
+package org.opensearch.common.geo.builders;
diff --git a/server/src/main/java/org/opensearch/common/geo/package-info.java b/server/src/main/java/org/opensearch/common/geo/package-info.java
new file mode 100644
index 0000000000000..8debc310d9c72
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/geo/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Geo package. */
+package org.opensearch.common.geo;
diff --git a/server/src/main/java/org/opensearch/common/geo/parsers/CoordinateNode.java b/server/src/main/java/org/opensearch/common/geo/parsers/CoordinateNode.java
index c4c091b0e25fe..670f0dde76ca5 100644
--- a/server/src/main/java/org/opensearch/common/geo/parsers/CoordinateNode.java
+++ b/server/src/main/java/org/opensearch/common/geo/parsers/CoordinateNode.java
@@ -31,19 +31,22 @@
 
 package org.opensearch.common.geo.parsers;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * Node used to represent a tree of coordinates.
  * <p>
  * Can either be a leaf node consisting of a Coordinate, or a parent with
  * children
+ *
+ * @opensearch.internal
  */
 public class CoordinateNode implements ToXContentObject {
     public final Coordinate coordinate;
diff --git a/server/src/main/java/org/opensearch/common/geo/parsers/GeoJsonParser.java b/server/src/main/java/org/opensearch/common/geo/parsers/GeoJsonParser.java
index 45ad538187fa4..37d42ce600b6d 100644
--- a/server/src/main/java/org/opensearch/common/geo/parsers/GeoJsonParser.java
+++ b/server/src/main/java/org/opensearch/common/geo/parsers/GeoJsonParser.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.common.geo.parsers;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.geo.GeoPoint;
@@ -41,18 +40,22 @@
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder.Orientation;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentSubParser;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentSubParser;
 import org.opensearch.index.mapper.AbstractShapeGeometryFieldMapper;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * Parses shape geometry represented in geojson
  *
  * complies with geojson specification: https://tools.ietf.org/html/rfc7946
+ *
+ * @opensearch.internal
  */
 abstract class GeoJsonParser {
     protected static ShapeBuilder parse(XContentParser parser, AbstractShapeGeometryFieldMapper shapeMapper) throws IOException {
diff --git a/server/src/main/java/org/opensearch/common/geo/parsers/GeoWKTParser.java b/server/src/main/java/org/opensearch/common/geo/parsers/GeoWKTParser.java
index 7aa5b0a165f90..d99d1daf46a2a 100644
--- a/server/src/main/java/org/opensearch/common/geo/parsers/GeoWKTParser.java
+++ b/server/src/main/java/org/opensearch/common/geo/parsers/GeoWKTParser.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.common.geo.parsers;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.geo.GeoPoint;
@@ -47,7 +46,7 @@
 import org.opensearch.common.geo.builders.PolygonBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.logging.Loggers;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.AbstractShapeGeometryFieldMapper;
 
 import java.io.IOException;
@@ -55,11 +54,15 @@
 import java.io.StringReader;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * Parses shape geometry represented in WKT format
  *
  * complies with OGC® document: 12-063r5 and ISO/IEC 13249-3:2016 standard
  * located at http://docs.opengeospatial.org/is/12-063r5/12-063r5.html
+ *
+ * @opensearch.internal
  */
 public class GeoWKTParser {
     public static final String EMPTY = "EMPTY";
diff --git a/server/src/main/java/org/opensearch/common/geo/parsers/ShapeParser.java b/server/src/main/java/org/opensearch/common/geo/parsers/ShapeParser.java
index f2670fd4efff5..fcd139bc0db8a 100644
--- a/server/src/main/java/org/opensearch/common/geo/parsers/ShapeParser.java
+++ b/server/src/main/java/org/opensearch/common/geo/parsers/ShapeParser.java
@@ -32,13 +32,13 @@
 package org.opensearch.common.geo.parsers;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.support.MapXContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.AbstractGeometryFieldMapper;
 import org.opensearch.index.mapper.AbstractShapeGeometryFieldMapper;
 
@@ -47,6 +47,8 @@
 
 /**
  * first point of entry for a shape parser
+ *
+ * @opensearch.internal
  */
 public interface ShapeParser {
     ParseField FIELD_TYPE = new ParseField("type");
diff --git a/server/src/main/java/org/opensearch/common/geo/parsers/package-info.java b/server/src/main/java/org/opensearch/common/geo/parsers/package-info.java
new file mode 100644
index 0000000000000..a465462d5d7de
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/geo/parsers/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Geo Parsers package. */
+package org.opensearch.common.geo.parsers;
diff --git a/server/src/main/java/org/opensearch/common/hash/MessageDigests.java b/server/src/main/java/org/opensearch/common/hash/MessageDigests.java
index c2a294828332d..f53f60a3a97a3 100644
--- a/server/src/main/java/org/opensearch/common/hash/MessageDigests.java
+++ b/server/src/main/java/org/opensearch/common/hash/MessageDigests.java
@@ -40,6 +40,8 @@
  * This MessageDigests class provides convenience methods for obtaining
  * thread local {@link MessageDigest} instances for MD5, SHA-1, and
  * SHA-256 message digests.
+ *
+ * @opensearch.internal
  */
 public final class MessageDigests {
 
diff --git a/server/src/main/java/org/opensearch/common/hash/MurmurHash3.java b/server/src/main/java/org/opensearch/common/hash/MurmurHash3.java
index f8b8b92027bba..8ba0bd7ee1be4 100644
--- a/server/src/main/java/org/opensearch/common/hash/MurmurHash3.java
+++ b/server/src/main/java/org/opensearch/common/hash/MurmurHash3.java
@@ -38,12 +38,16 @@
 
 /**
  * MurmurHash3 hashing functions.
+ *
+ * @opensearch.internal
  */
 public enum MurmurHash3 {
     ;
 
     /**
      * A 128-bits hash.
+     *
+     * @opensearch.internal
      */
     public static class Hash128 {
         /** lower 64 bits part **/
diff --git a/server/src/main/java/org/opensearch/common/hash/package-info.java b/server/src/main/java/org/opensearch/common/hash/package-info.java
new file mode 100644
index 0000000000000..1babf570e7264
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/hash/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base hashing package. */
+package org.opensearch.common.hash;
diff --git a/server/src/main/java/org/opensearch/common/inject/AbstractModule.java b/server/src/main/java/org/opensearch/common/inject/AbstractModule.java
index da0473dd25e01..7d2b65c23b6c2 100644
--- a/server/src/main/java/org/opensearch/common/inject/AbstractModule.java
+++ b/server/src/main/java/org/opensearch/common/inject/AbstractModule.java
@@ -57,6 +57,8 @@
  * </pre>
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractModule implements Module {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/AbstractProcessor.java b/server/src/main/java/org/opensearch/common/inject/AbstractProcessor.java
index 53010c50baf02..bc9624b9a13e7 100644
--- a/server/src/main/java/org/opensearch/common/inject/AbstractProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/AbstractProcessor.java
@@ -53,6 +53,8 @@
  * handled element.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 abstract class AbstractProcessor implements ElementVisitor<Boolean> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Binder.java b/server/src/main/java/org/opensearch/common/inject/Binder.java
index 3782734b0d927..a733a19608ac1 100644
--- a/server/src/main/java/org/opensearch/common/inject/Binder.java
+++ b/server/src/main/java/org/opensearch/common/inject/Binder.java
@@ -197,6 +197,8 @@
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
  * @author kevinb@google.com (Kevin Bourrillion)
+ *
+ * @opensearch.internal
  */
 public interface Binder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Binding.java b/server/src/main/java/org/opensearch/common/inject/Binding.java
index d40aec8a25d6d..53d02e37502af 100644
--- a/server/src/main/java/org/opensearch/common/inject/Binding.java
+++ b/server/src/main/java/org/opensearch/common/inject/Binding.java
@@ -68,6 +68,8 @@
  * @param <T> the bound type. The injected is always assignable to this type.
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public interface Binding<T> extends Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/BindingAnnotation.java b/server/src/main/java/org/opensearch/common/inject/BindingAnnotation.java
index 183ee13db162d..430b204c3e640 100644
--- a/server/src/main/java/org/opensearch/common/inject/BindingAnnotation.java
+++ b/server/src/main/java/org/opensearch/common/inject/BindingAnnotation.java
@@ -47,6 +47,8 @@
  * </pre>
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Target(ANNOTATION_TYPE)
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/BindingProcessor.java b/server/src/main/java/org/opensearch/common/inject/BindingProcessor.java
index 671123f2df767..f0edad2df8bcc 100644
--- a/server/src/main/java/org/opensearch/common/inject/BindingProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/BindingProcessor.java
@@ -67,6 +67,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class BindingProcessor extends AbstractProcessor {
 
@@ -274,7 +276,7 @@ private void putBinding(BindingImpl<?> binding) {
         }
 
         // prevent the parent from creating a JIT binding for this key
-        injector.state.parent().blacklist(key);
+        injector.state.parent().denylist(key);
         injector.state.putBinding(key, binding);
     }
 
@@ -312,6 +314,11 @@ private boolean isOkayDuplicate(Binding<?> original, BindingImpl<?> binding) {
     );
     // TODO(jessewilson): fix BuiltInModule, then add Stage
 
+    /**
+     * A listener for a process creation
+     *
+     * @opensearch.internal
+     */
     interface CreationListener {
         void notify(Errors errors);
     }
diff --git a/server/src/main/java/org/opensearch/common/inject/BoundProviderFactory.java b/server/src/main/java/org/opensearch/common/inject/BoundProviderFactory.java
index ba73fbb0848f7..687da29eb27d3 100644
--- a/server/src/main/java/org/opensearch/common/inject/BoundProviderFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/BoundProviderFactory.java
@@ -38,6 +38,8 @@
 
 /**
  * Delegates to a custom factory which is also bound in the injector.
+ *
+ * @opensearch.internal
  */
 class BoundProviderFactory<T> implements InternalFactory<T>, CreationListener {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConfigurationException.java b/server/src/main/java/org/opensearch/common/inject/ConfigurationException.java
index b62fe8f753505..4379a93482560 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConfigurationException.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConfigurationException.java
@@ -45,6 +45,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class ConfigurationException extends RuntimeException {
     private final Set<Message> messages;
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstantFactory.java b/server/src/main/java/org/opensearch/common/inject/ConstantFactory.java
index 2b1c6aa258226..935448d811532 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstantFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstantFactory.java
@@ -37,7 +37,11 @@
 import org.opensearch.common.inject.spi.Dependency;
 
 /**
+ * Constant factory.
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 class ConstantFactory<T> implements InternalFactory<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstructionProxy.java b/server/src/main/java/org/opensearch/common/inject/ConstructionProxy.java
index 6a8ca2ac820f9..7d30e3307d500 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstructionProxy.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstructionProxy.java
@@ -39,6 +39,8 @@
  * {@code T}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 interface ConstructionProxy<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstructionProxyFactory.java b/server/src/main/java/org/opensearch/common/inject/ConstructionProxyFactory.java
index f84f7c03a2caf..5b1a3f453d2f0 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstructionProxyFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstructionProxyFactory.java
@@ -33,6 +33,8 @@
  * Creates {@link ConstructionProxy} instances.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 interface ConstructionProxyFactory<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstructorBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/ConstructorBindingImpl.java
index 5f8458e76d349..8027ff74a4e21 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstructorBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstructorBindingImpl.java
@@ -44,6 +44,11 @@
 import java.util.HashSet;
 import java.util.Set;
 
+/**
+ * Constructor binding implementation
+ *
+ * @opensearch.internal
+ */
 class ConstructorBindingImpl<T> extends BindingImpl<T> implements ConstructorBinding<T> {
 
     private final Factory<T> factory;
@@ -115,6 +120,11 @@ public String toString() {
             .toString();
     }
 
+    /**
+     * Factory to build a binding object
+     *
+     * @opensearch.internal
+     */
     private static class Factory<T> implements InternalFactory<T> {
         private ConstructorInjector<T> constructorInjector;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstructorInjector.java b/server/src/main/java/org/opensearch/common/inject/ConstructorInjector.java
index a83eed858fb0b..ff8806d1fda98 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstructorInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstructorInjector.java
@@ -43,6 +43,8 @@
  * methods are injected.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 class ConstructorInjector<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ConstructorInjectorStore.java b/server/src/main/java/org/opensearch/common/inject/ConstructorInjectorStore.java
index d06896c2b4243..220de16201cf7 100644
--- a/server/src/main/java/org/opensearch/common/inject/ConstructorInjectorStore.java
+++ b/server/src/main/java/org/opensearch/common/inject/ConstructorInjectorStore.java
@@ -38,6 +38,8 @@
  * Constructor injectors by type.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class ConstructorInjectorStore {
     private final InjectorImpl injector;
diff --git a/server/src/main/java/org/opensearch/common/inject/ContextualCallable.java b/server/src/main/java/org/opensearch/common/inject/ContextualCallable.java
index 0e8404898aad2..22afccdaf12c0 100644
--- a/server/src/main/java/org/opensearch/common/inject/ContextualCallable.java
+++ b/server/src/main/java/org/opensearch/common/inject/ContextualCallable.java
@@ -33,7 +33,11 @@
 import org.opensearch.common.inject.internal.InternalContext;
 
 /**
+ * Contextual callable
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 interface ContextualCallable<T> {
     T call(InternalContext context) throws ErrorsException;
diff --git a/server/src/main/java/org/opensearch/common/inject/CreationException.java b/server/src/main/java/org/opensearch/common/inject/CreationException.java
index 9ab1c882e9d51..8b2271ba3630e 100644
--- a/server/src/main/java/org/opensearch/common/inject/CreationException.java
+++ b/server/src/main/java/org/opensearch/common/inject/CreationException.java
@@ -39,6 +39,8 @@
  * errors. Clients should catch this exception, log it, and stop execution.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class CreationException extends RuntimeException {
     private final Collection<Message> messages;
diff --git a/server/src/main/java/org/opensearch/common/inject/DefaultConstructionProxyFactory.java b/server/src/main/java/org/opensearch/common/inject/DefaultConstructionProxyFactory.java
index cdc6bf36034df..146398714b78d 100644
--- a/server/src/main/java/org/opensearch/common/inject/DefaultConstructionProxyFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/DefaultConstructionProxyFactory.java
@@ -38,6 +38,8 @@
  * Produces construction proxies that invoke the class constructor.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 class DefaultConstructionProxyFactory<T> implements ConstructionProxyFactory<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/DeferredLookups.java b/server/src/main/java/org/opensearch/common/inject/DeferredLookups.java
index 20a437e0a80a3..9004cba954bce 100644
--- a/server/src/main/java/org/opensearch/common/inject/DeferredLookups.java
+++ b/server/src/main/java/org/opensearch/common/inject/DeferredLookups.java
@@ -42,6 +42,8 @@
  * creation it's necessary to {@link #initialize initialize} these lookups.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class DeferredLookups implements Lookups {
     private final InjectorImpl injector;
diff --git a/server/src/main/java/org/opensearch/common/inject/EncounterImpl.java b/server/src/main/java/org/opensearch/common/inject/EncounterImpl.java
index 296a176ab83bc..39b9574b62ba3 100644
--- a/server/src/main/java/org/opensearch/common/inject/EncounterImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/EncounterImpl.java
@@ -39,7 +39,11 @@
 import java.util.List;
 
 /**
+ * Encounter implementation
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 final class EncounterImpl<T> implements TypeEncounter<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Exposed.java b/server/src/main/java/org/opensearch/common/inject/Exposed.java
index 65f7f3037714c..204d74ca096b7 100644
--- a/server/src/main/java/org/opensearch/common/inject/Exposed.java
+++ b/server/src/main/java/org/opensearch/common/inject/Exposed.java
@@ -42,6 +42,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 @Target(ElementType.METHOD)
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/ExposedKeyFactory.java b/server/src/main/java/org/opensearch/common/inject/ExposedKeyFactory.java
index 3983984470c18..9a07bcf1adc00 100644
--- a/server/src/main/java/org/opensearch/common/inject/ExposedKeyFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/ExposedKeyFactory.java
@@ -40,6 +40,8 @@
 /**
  * This factory exists in a parent injector. When invoked, it retrieves its value from a child
  * injector.
+ *
+ * @opensearch.internal
  */
 class ExposedKeyFactory<T> implements InternalFactory<T>, BindingProcessor.CreationListener {
     private final Key<T> key;
diff --git a/server/src/main/java/org/opensearch/common/inject/FactoryProxy.java b/server/src/main/java/org/opensearch/common/inject/FactoryProxy.java
index 97146198e4b95..ffb1873efc1bb 100644
--- a/server/src/main/java/org/opensearch/common/inject/FactoryProxy.java
+++ b/server/src/main/java/org/opensearch/common/inject/FactoryProxy.java
@@ -38,6 +38,8 @@
 
 /**
  * A placeholder which enables us to swap in the real factory once the injector is created.
+ *
+ * @opensearch.internal
  */
 class FactoryProxy<T> implements InternalFactory<T>, BindingProcessor.CreationListener {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Guice.java b/server/src/main/java/org/opensearch/common/inject/Guice.java
index 1ffdd5267fd6e..6513f720bea98 100644
--- a/server/src/main/java/org/opensearch/common/inject/Guice.java
+++ b/server/src/main/java/org/opensearch/common/inject/Guice.java
@@ -57,6 +57,8 @@
  *       }
  *     }
  * </pre>
+ *
+ * @opensearch.internal
  */
 public final class Guice {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ImplementedBy.java b/server/src/main/java/org/opensearch/common/inject/ImplementedBy.java
index 05df90d9dba78..1d0fec8033f62 100644
--- a/server/src/main/java/org/opensearch/common/inject/ImplementedBy.java
+++ b/server/src/main/java/org/opensearch/common/inject/ImplementedBy.java
@@ -39,6 +39,8 @@
  * A pointer to the default implementation of a type.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Retention(RUNTIME)
 @Target(TYPE)
diff --git a/server/src/main/java/org/opensearch/common/inject/InheritingState.java b/server/src/main/java/org/opensearch/common/inject/InheritingState.java
index 70a2fb335cca5..dc31de4e20084 100644
--- a/server/src/main/java/org/opensearch/common/inject/InheritingState.java
+++ b/server/src/main/java/org/opensearch/common/inject/InheritingState.java
@@ -49,7 +49,11 @@
 import static java.util.Collections.emptySet;
 
 /**
+ * Inheriting state.
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class InheritingState implements State {
 
@@ -143,18 +147,18 @@ public List<TypeListenerBinding> getTypeListenerBindings() {
     }
 
     @Override
-    public void blacklist(Key<?> key) {
-        parent.blacklist(key);
+    public void denylist(Key<?> key) {
+        parent.denylist(key);
         denylistedKeys.add(key);
     }
 
     @Override
-    public boolean isBlacklisted(Key<?> key) {
+    public boolean isDenylisted(Key<?> key) {
         return denylistedKeys.contains(key);
     }
 
     @Override
-    public void clearBlacklisted() {
+    public void clearDenylisted() {
         denylistedKeys = new WeakKeySet();
     }
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Initializable.java b/server/src/main/java/org/opensearch/common/inject/Initializable.java
index 779d50bbfcea0..9dbc26645fad1 100644
--- a/server/src/main/java/org/opensearch/common/inject/Initializable.java
+++ b/server/src/main/java/org/opensearch/common/inject/Initializable.java
@@ -36,6 +36,8 @@
  * Holds a reference that requires initialization to be performed before it can be used.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 interface Initializable<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Initializables.java b/server/src/main/java/org/opensearch/common/inject/Initializables.java
index 4ace6a059c847..6d1d5b88e4306 100644
--- a/server/src/main/java/org/opensearch/common/inject/Initializables.java
+++ b/server/src/main/java/org/opensearch/common/inject/Initializables.java
@@ -33,7 +33,11 @@
 import org.opensearch.common.inject.internal.ErrorsException;
 
 /**
+ * Initializables.
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class Initializables {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Initializer.java b/server/src/main/java/org/opensearch/common/inject/Initializer.java
index 8b333f7ac29ed..e806eba6df707 100644
--- a/server/src/main/java/org/opensearch/common/inject/Initializer.java
+++ b/server/src/main/java/org/opensearch/common/inject/Initializer.java
@@ -46,6 +46,8 @@
  * {@link Initializable}, which attempts to perform injection before use.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class Initializer {
     /**
diff --git a/server/src/main/java/org/opensearch/common/inject/Inject.java b/server/src/main/java/org/opensearch/common/inject/Inject.java
index 658d5dcd1ae7c..0c58238459d42 100644
--- a/server/src/main/java/org/opensearch/common/inject/Inject.java
+++ b/server/src/main/java/org/opensearch/common/inject/Inject.java
@@ -60,6 +60,8 @@
  * specifier (private, default, protected, public).
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Target({ METHOD, CONSTRUCTOR, FIELD })
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/InjectionRequestProcessor.java b/server/src/main/java/org/opensearch/common/inject/InjectionRequestProcessor.java
index 63740859ba0d5..062e1bb1257f1 100644
--- a/server/src/main/java/org/opensearch/common/inject/InjectionRequestProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/InjectionRequestProcessor.java
@@ -46,6 +46,8 @@
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
  * @author mikeward@google.com (Mike Ward)
+ *
+ * @opensearch.internal
  */
 class InjectionRequestProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Injector.java b/server/src/main/java/org/opensearch/common/inject/Injector.java
index adf8a6c742f67..ff212c6313371 100644
--- a/server/src/main/java/org/opensearch/common/inject/Injector.java
+++ b/server/src/main/java/org/opensearch/common/inject/Injector.java
@@ -53,6 +53,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public interface Injector {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/InjectorBuilder.java b/server/src/main/java/org/opensearch/common/inject/InjectorBuilder.java
index 944ff64d508ac..3dd858356ba16 100644
--- a/server/src/main/java/org/opensearch/common/inject/InjectorBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/InjectorBuilder.java
@@ -56,6 +56,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class InjectorBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/InjectorImpl.java b/server/src/main/java/org/opensearch/common/inject/InjectorImpl.java
index 3c888cd92b226..f004f5e418b26 100644
--- a/server/src/main/java/org/opensearch/common/inject/InjectorImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/InjectorImpl.java
@@ -72,6 +72,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @see InjectorBuilder
+ *
+ * @opensearch.internal
  */
 class InjectorImpl implements Injector, Lookups {
     final State state;
@@ -199,6 +201,11 @@ private <T> BindingImpl<Provider<T>> createProviderBinding(Key<Provider<T>> key,
         return new ProviderBindingImpl<>(this, key, delegate);
     }
 
+    /**
+     * Implementation for a binding object
+     *
+     * @opensearch.internal
+     */
     static class ProviderBindingImpl<T> extends BindingImpl<Provider<T>> implements ProviderBinding<Provider<T>> {
         final BindingImpl<T> providedBinding;
 
@@ -286,6 +293,11 @@ private <T> BindingImpl<T> convertConstantStringBinding(Key<T> key, Errors error
         }
     }
 
+    /**
+     * Implementation for a converted constant
+     *
+     * @opensearch.internal
+     */
     private static class ConvertedConstantBindingImpl<T> extends BindingImpl<T> implements ConvertedConstantBinding<T> {
         final T value;
         final Provider<T> provider;
@@ -530,12 +542,12 @@ public T get(Errors errors, InternalContext context, Dependency<?> dependency) t
      * other ancestor injectors until this injector is tried.
      */
     private <T> BindingImpl<T> createJustInTimeBindingRecursive(Key<T> key, Errors errors) throws ErrorsException {
-        if (state.isBlacklisted(key)) {
+        if (state.isDenylisted(key)) {
             throw errors.childBindingAlreadySet(key).toException();
         }
 
         BindingImpl<T> binding = createJustInTimeBinding(key, errors);
-        state.parent().blacklist(key);
+        state.parent().denylist(key);
         jitBindings.put(key, binding);
         return binding;
     }
@@ -555,7 +567,7 @@ private <T> BindingImpl<T> createJustInTimeBindingRecursive(Key<T> key, Errors e
      *          if the binding cannot be created.
      */
     <T> BindingImpl<T> createJustInTimeBinding(Key<T> key, Errors errors) throws ErrorsException {
-        if (state.isBlacklisted(key)) {
+        if (state.isDenylisted(key)) {
             throw errors.childBindingAlreadySet(key).toException();
         }
 
@@ -607,6 +619,11 @@ <T> InternalFactory<? extends T> getInternalFactory(Key<T> key, Errors errors) t
         return getBindingOrThrow(key, errors).getInternalFactory();
     }
 
+    /**
+     * Multimap for java bindings
+     *
+     * @opensearch.internal
+     */
     private static class BindingsMultimap {
         final Map<TypeLiteral<?>, List<Binding<?>>> multimap = new HashMap<>();
 
@@ -659,6 +676,8 @@ <T> SingleParameterInjector<T> createParameterInjector(final Dependency<T> depen
 
     /**
      * Invokes a method.
+     *
+     * @opensearch.internal
      */
     interface MethodInvoker {
         Object invoke(Object target, Object... parameters) throws IllegalAccessException, InvocationTargetException;
@@ -805,7 +824,7 @@ public String toString() {
 
     // ES_GUICE: clear caches
     public void clearCache() {
-        state.clearBlacklisted();
+        state.clearDenylisted();
         constructors = new ConstructorInjectorStore(this);
         membersInjectorStore = new MembersInjectorStore(this, state.getTypeListenerBindings());
         jitBindings = new HashMap<>();
diff --git a/server/src/main/java/org/opensearch/common/inject/InjectorShell.java b/server/src/main/java/org/opensearch/common/inject/InjectorShell.java
index 0af8aa5a895a0..006d39b6d8348 100644
--- a/server/src/main/java/org/opensearch/common/inject/InjectorShell.java
+++ b/server/src/main/java/org/opensearch/common/inject/InjectorShell.java
@@ -58,6 +58,8 @@
  * of injectors in batch.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class InjectorShell {
 
@@ -77,6 +79,11 @@ List<Element> getElements() {
         return elements;
     }
 
+    /**
+     * Builder for an injector
+     *
+     * @opensearch.internal
+     */
     static class Builder {
         private final List<Element> elements = new ArrayList<>();
         private final List<Module> modules = new ArrayList<>();
@@ -215,6 +222,11 @@ private static void bindInjector(InjectorImpl injector) {
         );
     }
 
+    /**
+     * The factory for the injector
+     *
+     * @opensearch.internal
+     */
     private static class InjectorFactory implements InternalFactory<Injector>, Provider<Injector> {
         private final Injector injector;
 
@@ -259,6 +271,11 @@ private static void bindLogger(InjectorImpl injector) {
         );
     }
 
+    /**
+     * Factory for a logger
+     *
+     * @opensearch.internal
+     */
     private static class LoggerFactory implements InternalFactory<Logger>, Provider<Logger> {
         @Override
         public Logger get(Errors errors, InternalContext context, Dependency<?> dependency) {
@@ -279,6 +296,11 @@ public String toString() {
         }
     }
 
+    /**
+     * The root module
+     *
+     * @opensearch.internal
+     */
     private static class RootModule implements Module {
         final Stage stage;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/InternalFactoryToProviderAdapter.java b/server/src/main/java/org/opensearch/common/inject/InternalFactoryToProviderAdapter.java
index 3eb40b8d567a0..9925418c34a30 100644
--- a/server/src/main/java/org/opensearch/common/inject/InternalFactoryToProviderAdapter.java
+++ b/server/src/main/java/org/opensearch/common/inject/InternalFactoryToProviderAdapter.java
@@ -39,7 +39,11 @@
 import java.util.Objects;
 
 /**
+ * Adapats internal factory to a provider
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 class InternalFactoryToProviderAdapter<T> implements InternalFactory<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Key.java b/server/src/main/java/org/opensearch/common/inject/Key.java
index d36791c154450..cd305353a555d 100644
--- a/server/src/main/java/org/opensearch/common/inject/Key.java
+++ b/server/src/main/java/org/opensearch/common/inject/Key.java
@@ -58,6 +58,8 @@
  * types will be replaced with their wrapper types when keys are created.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Key<T> {
 
@@ -323,6 +325,11 @@ Key<T> withoutAttributes() {
         return new Key<>(typeLiteral, annotationStrategy.withoutAttributes());
     }
 
+    /**
+     * Strategy for annotations
+     *
+     * @opensearch.internal
+     */
     interface AnnotationStrategy {
         Annotation getAnnotation();
 
@@ -411,6 +418,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Strategy for an annotation
+     *
+     * @opensearch.internal
+     */
     // this class not test-covered
     static class AnnotationInstanceStrategy implements AnnotationStrategy {
 
@@ -461,6 +473,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Type of annotation
+     *
+     * @opensearch.internal
+     */
     static class AnnotationTypeStrategy implements AnnotationStrategy {
 
         final Class<? extends Annotation> annotationType;
diff --git a/server/src/main/java/org/opensearch/common/inject/LookupProcessor.java b/server/src/main/java/org/opensearch/common/inject/LookupProcessor.java
index 153dad9ce0cf8..c9d1546ca9e92 100644
--- a/server/src/main/java/org/opensearch/common/inject/LookupProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/LookupProcessor.java
@@ -39,6 +39,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class LookupProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Lookups.java b/server/src/main/java/org/opensearch/common/inject/Lookups.java
index 798a665cdb3d0..241bae072217a 100644
--- a/server/src/main/java/org/opensearch/common/inject/Lookups.java
+++ b/server/src/main/java/org/opensearch/common/inject/Lookups.java
@@ -34,6 +34,8 @@
  * the injector has been created.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 interface Lookups {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/MembersInjector.java b/server/src/main/java/org/opensearch/common/inject/MembersInjector.java
index 132616ac35a08..891762375d5a2 100644
--- a/server/src/main/java/org/opensearch/common/inject/MembersInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/MembersInjector.java
@@ -37,6 +37,8 @@
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface MembersInjector<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/MembersInjectorImpl.java b/server/src/main/java/org/opensearch/common/inject/MembersInjectorImpl.java
index 507b21f872b0a..47eca6840b3e2 100644
--- a/server/src/main/java/org/opensearch/common/inject/MembersInjectorImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/MembersInjectorImpl.java
@@ -45,6 +45,8 @@
  * Injects members of instances of a given type.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class MembersInjectorImpl<T> implements MembersInjector<T> {
     private final TypeLiteral<T> typeLiteral;
diff --git a/server/src/main/java/org/opensearch/common/inject/MembersInjectorStore.java b/server/src/main/java/org/opensearch/common/inject/MembersInjectorStore.java
index 207803abe6df7..c63460d1a9a96 100644
--- a/server/src/main/java/org/opensearch/common/inject/MembersInjectorStore.java
+++ b/server/src/main/java/org/opensearch/common/inject/MembersInjectorStore.java
@@ -45,6 +45,8 @@
  * Members injectors by type.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class MembersInjectorStore {
     private final InjectorImpl injector;
diff --git a/server/src/main/java/org/opensearch/common/inject/MessageProcessor.java b/server/src/main/java/org/opensearch/common/inject/MessageProcessor.java
index e2f06cfeaf144..f81babc803019 100644
--- a/server/src/main/java/org/opensearch/common/inject/MessageProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/MessageProcessor.java
@@ -37,6 +37,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class MessageProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Module.java b/server/src/main/java/org/opensearch/common/inject/Module.java
index 49a12714c8de4..e66044ff26c40 100644
--- a/server/src/main/java/org/opensearch/common/inject/Module.java
+++ b/server/src/main/java/org/opensearch/common/inject/Module.java
@@ -29,6 +29,8 @@
 
 package org.opensearch.common.inject;
 
+import org.opensearch.common.annotation.PublicApi;
+
 /**
  * A module contributes configuration information, typically interface
  * bindings, which will be used to create an {@link Injector}. A Guice-based
@@ -42,7 +44,10 @@
  * will be created for all methods annotated with {@literal @}{@link Provides}.
  * Use scope and binding annotations on these methods to configure the
  * bindings.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface Module {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/inject/ModulesBuilder.java b/server/src/main/java/org/opensearch/common/inject/ModulesBuilder.java
index 0ad304ad90d5c..55fc263ffc574 100644
--- a/server/src/main/java/org/opensearch/common/inject/ModulesBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/ModulesBuilder.java
@@ -37,6 +37,11 @@
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * A modules builder
+ *
+ * @opensearch.internal
+ */
 public class ModulesBuilder implements Iterable<Module> {
 
     private final List<Module> modules = new ArrayList<>();
diff --git a/server/src/main/java/org/opensearch/common/inject/OutOfScopeException.java b/server/src/main/java/org/opensearch/common/inject/OutOfScopeException.java
index ed222d014fbc2..bf1d25498fb90 100644
--- a/server/src/main/java/org/opensearch/common/inject/OutOfScopeException.java
+++ b/server/src/main/java/org/opensearch/common/inject/OutOfScopeException.java
@@ -35,6 +35,8 @@
  *
  * @author kevinb@google.com (Kevin Bourrillion)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class OutOfScopeException extends RuntimeException {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/PreProcessModule.java b/server/src/main/java/org/opensearch/common/inject/PreProcessModule.java
index 48778fd78292a..e34e564d8e253 100644
--- a/server/src/main/java/org/opensearch/common/inject/PreProcessModule.java
+++ b/server/src/main/java/org/opensearch/common/inject/PreProcessModule.java
@@ -36,7 +36,7 @@
  * A module can implement this interface to allow to pre process other modules
  * before an injector is created.
  *
- *
+ * @opensearch.internal
  */
 public interface PreProcessModule {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/PrivateBinder.java b/server/src/main/java/org/opensearch/common/inject/PrivateBinder.java
index 22e334a52c9b7..87635880e29d8 100644
--- a/server/src/main/java/org/opensearch/common/inject/PrivateBinder.java
+++ b/server/src/main/java/org/opensearch/common/inject/PrivateBinder.java
@@ -37,6 +37,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface PrivateBinder extends Binder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/PrivateElementProcessor.java b/server/src/main/java/org/opensearch/common/inject/PrivateElementProcessor.java
index 103fb2f9049dd..b1a97b8defcd9 100644
--- a/server/src/main/java/org/opensearch/common/inject/PrivateElementProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/PrivateElementProcessor.java
@@ -39,6 +39,8 @@
  * Handles {@link Binder#newPrivateBinder()} elements.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class PrivateElementProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/PrivateModule.java b/server/src/main/java/org/opensearch/common/inject/PrivateModule.java
index df47d5eb261f3..09c02c944c316 100644
--- a/server/src/main/java/org/opensearch/common/inject/PrivateModule.java
+++ b/server/src/main/java/org/opensearch/common/inject/PrivateModule.java
@@ -83,6 +83,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public abstract class PrivateModule implements Module {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ProvidedBy.java b/server/src/main/java/org/opensearch/common/inject/ProvidedBy.java
index 4a8c9dece954f..b6879a9ea3dc0 100644
--- a/server/src/main/java/org/opensearch/common/inject/ProvidedBy.java
+++ b/server/src/main/java/org/opensearch/common/inject/ProvidedBy.java
@@ -39,6 +39,8 @@
  * A pointer to the default provider type for a type.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Retention(RUNTIME)
 @Target(TYPE)
diff --git a/server/src/main/java/org/opensearch/common/inject/Provider.java b/server/src/main/java/org/opensearch/common/inject/Provider.java
index 96c08d1f943fc..97f9e9ae503cd 100644
--- a/server/src/main/java/org/opensearch/common/inject/Provider.java
+++ b/server/src/main/java/org/opensearch/common/inject/Provider.java
@@ -49,6 +49,8 @@
  *
  * @param <T> the type of object this provides
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface Provider<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ProviderToInternalFactoryAdapter.java b/server/src/main/java/org/opensearch/common/inject/ProviderToInternalFactoryAdapter.java
index f67b601ca8662..c90d4dcf7469d 100644
--- a/server/src/main/java/org/opensearch/common/inject/ProviderToInternalFactoryAdapter.java
+++ b/server/src/main/java/org/opensearch/common/inject/ProviderToInternalFactoryAdapter.java
@@ -36,7 +36,11 @@
 import org.opensearch.common.inject.spi.Dependency;
 
 /**
+ * Adapts a provider to an internal factory.
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 class ProviderToInternalFactoryAdapter<T> implements Provider<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Provides.java b/server/src/main/java/org/opensearch/common/inject/Provides.java
index 694816b971692..5620b30774af5 100644
--- a/server/src/main/java/org/opensearch/common/inject/Provides.java
+++ b/server/src/main/java/org/opensearch/common/inject/Provides.java
@@ -42,6 +42,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 @Documented
 @Target(METHOD)
diff --git a/server/src/main/java/org/opensearch/common/inject/ProvisionException.java b/server/src/main/java/org/opensearch/common/inject/ProvisionException.java
index 122777f550c7a..452e7982ddca4 100644
--- a/server/src/main/java/org/opensearch/common/inject/ProvisionException.java
+++ b/server/src/main/java/org/opensearch/common/inject/ProvisionException.java
@@ -46,6 +46,8 @@
  * @author kevinb@google.com (Kevin Bourrillion)
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class ProvisionException extends RuntimeException {
     private final Set<Message> messages;
diff --git a/server/src/main/java/org/opensearch/common/inject/Reflection.java b/server/src/main/java/org/opensearch/common/inject/Reflection.java
index f835b3ea41d8e..296ac9a63a1de 100644
--- a/server/src/main/java/org/opensearch/common/inject/Reflection.java
+++ b/server/src/main/java/org/opensearch/common/inject/Reflection.java
@@ -43,6 +43,8 @@ class Reflection {
     /**
      * A placeholder. This enables us to continue processing and gather more
      * errors but blows up if you actually try to use it.
+     *
+     * @opensearch.internal
      */
     static class InvalidConstructor {
         InvalidConstructor() {
diff --git a/server/src/main/java/org/opensearch/common/inject/Scope.java b/server/src/main/java/org/opensearch/common/inject/Scope.java
index 97017e997aeba..a21495f522d5e 100644
--- a/server/src/main/java/org/opensearch/common/inject/Scope.java
+++ b/server/src/main/java/org/opensearch/common/inject/Scope.java
@@ -41,6 +41,8 @@
  * An example of a scope is {@link Scopes#SINGLETON}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface Scope {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/ScopeAnnotation.java b/server/src/main/java/org/opensearch/common/inject/ScopeAnnotation.java
index 88ed59025553b..5617112fb30c4 100644
--- a/server/src/main/java/org/opensearch/common/inject/ScopeAnnotation.java
+++ b/server/src/main/java/org/opensearch/common/inject/ScopeAnnotation.java
@@ -47,6 +47,8 @@
  * </pre>
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Target(ANNOTATION_TYPE)
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/ScopeBindingProcessor.java b/server/src/main/java/org/opensearch/common/inject/ScopeBindingProcessor.java
index 77a5f92074673..f36172ecd1779 100644
--- a/server/src/main/java/org/opensearch/common/inject/ScopeBindingProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/ScopeBindingProcessor.java
@@ -41,6 +41,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class ScopeBindingProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/Scopes.java b/server/src/main/java/org/opensearch/common/inject/Scopes.java
index a3821fdc7fa67..557455b31b02d 100644
--- a/server/src/main/java/org/opensearch/common/inject/Scopes.java
+++ b/server/src/main/java/org/opensearch/common/inject/Scopes.java
@@ -40,6 +40,8 @@
  * Built-in scope implementations.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Scopes {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/SingleFieldInjector.java b/server/src/main/java/org/opensearch/common/inject/SingleFieldInjector.java
index 8a6e1e446fca0..3d02213c743c1 100644
--- a/server/src/main/java/org/opensearch/common/inject/SingleFieldInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/SingleFieldInjector.java
@@ -40,6 +40,8 @@
 
 /**
  * Sets an injectable field.
+ *
+ * @opensearch.internal
  */
 class SingleFieldInjector implements SingleMemberInjector {
     final Field field;
diff --git a/server/src/main/java/org/opensearch/common/inject/SingleMemberInjector.java b/server/src/main/java/org/opensearch/common/inject/SingleMemberInjector.java
index 009fbcfb1128f..d26ed98ef91f8 100644
--- a/server/src/main/java/org/opensearch/common/inject/SingleMemberInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/SingleMemberInjector.java
@@ -35,6 +35,8 @@
 
 /**
  * Injects a field or method of a given object.
+ *
+ * @opensearch.internal
  */
 interface SingleMemberInjector {
     void inject(Errors errors, InternalContext context, Object o);
diff --git a/server/src/main/java/org/opensearch/common/inject/SingleMethodInjector.java b/server/src/main/java/org/opensearch/common/inject/SingleMethodInjector.java
index 6ca2b1b367f1a..600b953964010 100644
--- a/server/src/main/java/org/opensearch/common/inject/SingleMethodInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/SingleMethodInjector.java
@@ -41,6 +41,8 @@
 
 /**
  * Invokes an injectable method.
+ *
+ * @opensearch.internal
  */
 class SingleMethodInjector implements SingleMemberInjector {
     final MethodInvoker methodInvoker;
diff --git a/server/src/main/java/org/opensearch/common/inject/SingleParameterInjector.java b/server/src/main/java/org/opensearch/common/inject/SingleParameterInjector.java
index 7fa6cd1d5df18..cc6636d35c670 100644
--- a/server/src/main/java/org/opensearch/common/inject/SingleParameterInjector.java
+++ b/server/src/main/java/org/opensearch/common/inject/SingleParameterInjector.java
@@ -37,6 +37,8 @@
 
 /**
  * Resolves a single parameter, to be used in a constructor or method invocation.
+ *
+ * @opensearch.internal
  */
 class SingleParameterInjector<T> {
     private static final Object[] NO_ARGUMENTS = {};
diff --git a/server/src/main/java/org/opensearch/common/inject/Singleton.java b/server/src/main/java/org/opensearch/common/inject/Singleton.java
index d3d894e2d6cfe..29c743ae47e82 100644
--- a/server/src/main/java/org/opensearch/common/inject/Singleton.java
+++ b/server/src/main/java/org/opensearch/common/inject/Singleton.java
@@ -40,6 +40,8 @@
  * (per {@link Injector}) to be reused for all injections for that binding.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Target({ ElementType.TYPE, ElementType.METHOD })
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/Stage.java b/server/src/main/java/org/opensearch/common/inject/Stage.java
index befb6409d7457..d5996bd1363e9 100644
--- a/server/src/main/java/org/opensearch/common/inject/Stage.java
+++ b/server/src/main/java/org/opensearch/common/inject/Stage.java
@@ -33,6 +33,8 @@
  * The stage we're running in.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public enum Stage {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/State.java b/server/src/main/java/org/opensearch/common/inject/State.java
index 6a69e9547d707..3d90737f40dc2 100644
--- a/server/src/main/java/org/opensearch/common/inject/State.java
+++ b/server/src/main/java/org/opensearch/common/inject/State.java
@@ -46,6 +46,8 @@
  * injector data to be accessed as a unit.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 interface State {
 
@@ -106,15 +108,15 @@ public List<TypeListenerBinding> getTypeListenerBindings() {
         }
 
         @Override
-        public void blacklist(Key<?> key) {}
+        public void denylist(Key<?> key) {}
 
         @Override
-        public boolean isBlacklisted(Key<?> key) {
+        public boolean isDenylisted(Key<?> key) {
             return true;
         }
 
         @Override
-        public void clearBlacklisted() {}
+        public void clearDenylisted() {}
 
         @Override
         public void makeAllBindingsToEagerSingletons(Injector injector) {}
@@ -167,13 +169,13 @@ public Object lock() {
      * denylist their bound keys on their parent injectors to prevent just-in-time bindings on the
      * parent injector that would conflict.
      */
-    void blacklist(Key<?> key);
+    void denylist(Key<?> key);
 
     /**
      * Returns true if {@code key} is forbidden from being bound in this injector. This indicates that
      * one of this injector's descendent's has bound the key.
      */
-    boolean isBlacklisted(Key<?> key);
+    boolean isDenylisted(Key<?> key);
 
     /**
      * Returns the shared lock for all injector data. This is a low-granularity, high-contention lock
@@ -182,7 +184,7 @@ public Object lock() {
     Object lock();
 
     // ES_GUICE: clean denylist keys
-    void clearBlacklisted();
+    void clearDenylisted();
 
     void makeAllBindingsToEagerSingletons(Injector injector);
 }
diff --git a/server/src/main/java/org/opensearch/common/inject/TypeConverterBindingProcessor.java b/server/src/main/java/org/opensearch/common/inject/TypeConverterBindingProcessor.java
index 07b4628044904..abe8a24eead8d 100644
--- a/server/src/main/java/org/opensearch/common/inject/TypeConverterBindingProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/TypeConverterBindingProcessor.java
@@ -48,6 +48,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class TypeConverterBindingProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/TypeListenerBindingProcessor.java b/server/src/main/java/org/opensearch/common/inject/TypeListenerBindingProcessor.java
index 07916ccb1aeb4..64a47ab97cbb7 100644
--- a/server/src/main/java/org/opensearch/common/inject/TypeListenerBindingProcessor.java
+++ b/server/src/main/java/org/opensearch/common/inject/TypeListenerBindingProcessor.java
@@ -36,6 +36,8 @@
  * Handles {@link Binder#bindListener} commands.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class TypeListenerBindingProcessor extends AbstractProcessor {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/TypeLiteral.java b/server/src/main/java/org/opensearch/common/inject/TypeLiteral.java
index 6fb267a911fcf..f0cca2990b407 100644
--- a/server/src/main/java/org/opensearch/common/inject/TypeLiteral.java
+++ b/server/src/main/java/org/opensearch/common/inject/TypeLiteral.java
@@ -76,6 +76,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class TypeLiteral<T> {
 
@@ -268,6 +270,8 @@ Type resolveType(Type toResolve) {
      *
      * @param supertype a superclass of, or interface implemented by, this.
      * @since 2.0
+     *
+     * @opensearch.internal
      */
     public TypeLiteral<?> getSupertype(Class<?> supertype) {
         if (!supertype.isAssignableFrom(rawType)) {
diff --git a/server/src/main/java/org/opensearch/common/inject/WeakKeySet.java b/server/src/main/java/org/opensearch/common/inject/WeakKeySet.java
index 7ad49a7b9759c..44e3864d991ae 100644
--- a/server/src/main/java/org/opensearch/common/inject/WeakKeySet.java
+++ b/server/src/main/java/org/opensearch/common/inject/WeakKeySet.java
@@ -36,6 +36,8 @@
  * Minimal set that doesn't hold strong references to the contained keys.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 final class WeakKeySet {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/Assisted.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/Assisted.java
index 656260952c5d2..8379458a8c069 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/Assisted.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/Assisted.java
@@ -44,6 +44,8 @@
  *
  * @author jmourits@google.com (Jerome Mourits)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 @BindingAnnotation
 @Target({ FIELD, PARAMETER, METHOD })
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedConstructor.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedConstructor.java
index 663a859402a26..989eb26274101 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedConstructor.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedConstructor.java
@@ -48,6 +48,8 @@
  *
  * @author jmourits@google.com (Jerome Mourits)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class AssistedConstructor<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedInject.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedInject.java
index 4f2d9b7915175..976c148f95275 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedInject.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/AssistedInject.java
@@ -49,6 +49,8 @@
  *             annotation. When using that annotation, parameters are matched by name and type rather than
  *             by position. In addition, values that use the standard {@literal @Inject} constructor
  *             annotation are eligible for method interception.
+ *
+ * @opensearch.internal
  */
 @Target({ CONSTRUCTOR })
 @Retention(RUNTIME)
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/FactoryProvider.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/FactoryProvider.java
index 6f288a0c4c9a8..e7eb2fcc4727c 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/FactoryProvider.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/FactoryProvider.java
@@ -134,6 +134,8 @@
  * @author jmourits@google.com (Jerome Mourits)
  * @author jessewilson@google.com (Jesse Wilson)
  * @author dtm@google.com (Daniel Martin)
+ *
+ * @opensearch.internal
  */
 public class FactoryProvider<F> implements Provider<F>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/Parameter.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/Parameter.java
index 8f8df0a2ac373..960fc079e6438 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/Parameter.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/Parameter.java
@@ -43,6 +43,8 @@
  *
  * @author jmourits@google.com (Jerome Mourits)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class Parameter {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/assistedinject/ParameterListKey.java b/server/src/main/java/org/opensearch/common/inject/assistedinject/ParameterListKey.java
index 0f48371a89ec1..12474dfceb69b 100644
--- a/server/src/main/java/org/opensearch/common/inject/assistedinject/ParameterListKey.java
+++ b/server/src/main/java/org/opensearch/common/inject/assistedinject/ParameterListKey.java
@@ -42,6 +42,8 @@
  *
  * @author jmourits@google.com (Jerome Mourits)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class ParameterListKey {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedBindingBuilder.java
index 0a6aacb79ab54..bcd593a8cbf7b 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedBindingBuilder.java
@@ -35,6 +35,8 @@
  * See the EDSL examples at {@link org.opensearch.common.inject.Binder}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface AnnotatedBindingBuilder<T> extends LinkedBindingBuilder<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedConstantBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedConstantBindingBuilder.java
index 11e11e3b8cf7a..42c208a2b37ea 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedConstantBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedConstantBindingBuilder.java
@@ -35,6 +35,8 @@
  * See the EDSL examples at {@link org.opensearch.common.inject.Binder}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface AnnotatedConstantBindingBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedElementBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedElementBuilder.java
index b63e25b1baa42..f2d0916790b6b 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedElementBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/AnnotatedElementBuilder.java
@@ -36,6 +36,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface AnnotatedElementBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/ConstantBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/ConstantBindingBuilder.java
index b03c2a937f36b..595c477d3e28b 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/ConstantBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/ConstantBindingBuilder.java
@@ -31,6 +31,8 @@
 
 /**
  * Binds to a constant value.
+ *
+ * @opensearch.internal
  */
 public interface ConstantBindingBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/LinkedBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/LinkedBindingBuilder.java
index 708a2d632518f..2368fef16471c 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/LinkedBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/LinkedBindingBuilder.java
@@ -37,6 +37,8 @@
  * See the EDSL examples at {@link org.opensearch.common.inject.Binder}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface LinkedBindingBuilder<T> extends ScopedBindingBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/binder/ScopedBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/binder/ScopedBindingBuilder.java
index cd52cd8e574e9..73dd4414f17a2 100644
--- a/server/src/main/java/org/opensearch/common/inject/binder/ScopedBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/binder/ScopedBindingBuilder.java
@@ -37,6 +37,8 @@
  * See the EDSL examples at {@link org.opensearch.common.inject.Binder}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface ScopedBindingBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/AbstractBindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/internal/AbstractBindingBuilder.java
index a6622a3e6af7c..ba7951894b801 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/AbstractBindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/AbstractBindingBuilder.java
@@ -43,6 +43,8 @@
  * Bind a value or constant.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractBindingBuilder<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Annotations.java b/server/src/main/java/org/opensearch/common/inject/internal/Annotations.java
index 3b83bd9693df1..1d61acad60324 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Annotations.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Annotations.java
@@ -44,6 +44,8 @@
  * Annotation utilities.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Annotations {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/BindingBuilder.java b/server/src/main/java/org/opensearch/common/inject/internal/BindingBuilder.java
index d4927adafc258..9f5f0dc4a7bc6 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/BindingBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/BindingBuilder.java
@@ -52,6 +52,8 @@
  * Bind a non-constant key.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class BindingBuilder<T> extends AbstractBindingBuilder<T> implements AnnotatedBindingBuilder<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/BindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/BindingImpl.java
index 0365158d02461..1004398e844d8 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/BindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/BindingImpl.java
@@ -38,7 +38,11 @@
 import org.opensearch.common.inject.spi.InstanceBinding;
 
 /**
+ * A binding implementation
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public abstract class BindingImpl<T> implements Binding<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ConstantBindingBuilderImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/ConstantBindingBuilderImpl.java
index 62108baaea324..53883e8c4b8ae 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ConstantBindingBuilderImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ConstantBindingBuilderImpl.java
@@ -44,6 +44,8 @@
  * Bind a constant.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public final class ConstantBindingBuilderImpl<T> extends AbstractBindingBuilder<T>
     implements
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ConstructionContext.java b/server/src/main/java/org/opensearch/common/inject/internal/ConstructionContext.java
index 58988f16b1d2d..63ae0584fdee9 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ConstructionContext.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ConstructionContext.java
@@ -40,6 +40,8 @@
  * Context of a dependency construction. Used to manage circular references.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class ConstructionContext<T> {
 
@@ -105,6 +107,11 @@ public void setProxyDelegates(T delegate) {
         }
     }
 
+    /**
+     * An invocation handler that delegates the implementation
+     *
+     * @opensearch.internal
+     */
     static class DelegatingInvocationHandler<T> implements InvocationHandler {
 
         T delegate;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ErrorHandler.java b/server/src/main/java/org/opensearch/common/inject/internal/ErrorHandler.java
index cf3d3eaddc528..283c8c468401b 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ErrorHandler.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ErrorHandler.java
@@ -35,6 +35,8 @@
  * Handles errors in the Injector.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface ErrorHandler {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Errors.java b/server/src/main/java/org/opensearch/common/inject/internal/Errors.java
index 3a2a1b980c1e3..86d7ef2a2ca36 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Errors.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Errors.java
@@ -77,6 +77,8 @@
  * method with an errors object that includes its context.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public final class Errors {
 
@@ -590,6 +592,11 @@ public int size() {
         return root.errors == null ? 0 : root.errors.size();
     }
 
+    /**
+     * A converter
+     *
+     * @opensearch.internal
+     */
     private abstract static class Converter<T> {
 
         final Class<T> type;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ErrorsException.java b/server/src/main/java/org/opensearch/common/inject/internal/ErrorsException.java
index 555ec2bddbe2c..d472305ce860b 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ErrorsException.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ErrorsException.java
@@ -35,6 +35,8 @@
  * errors.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class ErrorsException extends Exception {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ExpirationTimer.java b/server/src/main/java/org/opensearch/common/inject/internal/ExpirationTimer.java
index 0c838e0a574a4..ab9d67a6a24eb 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ExpirationTimer.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ExpirationTimer.java
@@ -33,6 +33,8 @@
 
 /**
  * Timer used for entry expiration in MapMaker.
+ *
+ * @opensearch.internal
  */
 class ExpirationTimer {
     static Timer instance = new Timer(true);
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ExposedBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/ExposedBindingImpl.java
index d70892ee92e60..18d55ce703608 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ExposedBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ExposedBindingImpl.java
@@ -41,6 +41,11 @@
 
 import static java.util.Collections.singleton;
 
+/**
+ * Exposed binding implementation
+ *
+ * @opensearch.internal
+ */
 public class ExposedBindingImpl<T> extends BindingImpl<T> implements ExposedBinding<T> {
 
     private final PrivateElements privateElements;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ExposureBuilder.java b/server/src/main/java/org/opensearch/common/inject/internal/ExposureBuilder.java
index 46585b02ab0f1..792c208d872d4 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ExposureBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ExposureBuilder.java
@@ -38,6 +38,8 @@
 
 /**
  * For private binder's expose() method.
+ *
+ * @opensearch.internal
  */
 public class ExposureBuilder<T> implements AnnotatedElementBuilder {
     private final Binder binder;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/FailableCache.java b/server/src/main/java/org/opensearch/common/inject/internal/FailableCache.java
index 0c8495df8ddf2..a5d57f94cb670 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/FailableCache.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/FailableCache.java
@@ -36,6 +36,8 @@
  * exception is thrown on retrieval.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public abstract class FailableCache<K, V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/InstanceBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/InstanceBindingImpl.java
index 3b6741bbbcaac..22b1c8dd1cf85 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/InstanceBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/InstanceBindingImpl.java
@@ -45,6 +45,11 @@
 
 import static java.util.Collections.unmodifiableSet;
 
+/**
+ * Instance binding implementation
+ *
+ * @opensearch.internal
+ */
 public class InstanceBindingImpl<T> extends BindingImpl<T> implements InstanceBinding<T> {
 
     final T instance;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/InternalContext.java b/server/src/main/java/org/opensearch/common/inject/internal/InternalContext.java
index 79dc11677e043..7cde5c6a35f8d 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/InternalContext.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/InternalContext.java
@@ -39,6 +39,8 @@
  * dependencies.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public final class InternalContext {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/InternalFactory.java b/server/src/main/java/org/opensearch/common/inject/internal/InternalFactory.java
index 8d8e919cae8af..d7b8a5a4f49ef 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/InternalFactory.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/InternalFactory.java
@@ -35,6 +35,8 @@
  * Creates objects which will be injected.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface InternalFactory<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/LinkedBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/LinkedBindingImpl.java
index 2c03d582e53da..f81ec7517d4e3 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/LinkedBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/LinkedBindingImpl.java
@@ -35,6 +35,11 @@
 import org.opensearch.common.inject.spi.BindingTargetVisitor;
 import org.opensearch.common.inject.spi.LinkedKeyBinding;
 
+/**
+ * Linked binding implementation
+ *
+ * @opensearch.internal
+ */
 public final class LinkedBindingImpl<T> extends BindingImpl<T> implements LinkedKeyBinding<T> {
 
     final Key<? extends T> targetKey;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/LinkedProviderBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/LinkedProviderBindingImpl.java
index 80ae73cd4c223..5c8be66b21103 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/LinkedProviderBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/LinkedProviderBindingImpl.java
@@ -36,6 +36,11 @@
 import org.opensearch.common.inject.spi.BindingTargetVisitor;
 import org.opensearch.common.inject.spi.ProviderKeyBinding;
 
+/**
+ * Linked provider binding implementation
+ *
+ * @opensearch.internal
+ */
 public final class LinkedProviderBindingImpl<T> extends BindingImpl<T> implements ProviderKeyBinding<T> {
 
     final Key<? extends Provider<? extends T>> providerKey;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/MatcherAndConverter.java b/server/src/main/java/org/opensearch/common/inject/internal/MatcherAndConverter.java
index 4d744f2634da8..53051044b2f32 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/MatcherAndConverter.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/MatcherAndConverter.java
@@ -36,7 +36,11 @@
 import java.util.Objects;
 
 /**
+ * Matches and converts
+ *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public final class MatcherAndConverter {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/MoreTypes.java b/server/src/main/java/org/opensearch/common/inject/internal/MoreTypes.java
index ce215b3867793..6b9feedc9174e 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/MoreTypes.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/MoreTypes.java
@@ -57,6 +57,8 @@
  * public {@code Types} API.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class MoreTypes {
 
@@ -432,6 +434,11 @@ private static Class<?> declaringClassOf(TypeVariable typeVariable) {
         return genericDeclaration instanceof Class ? (Class<?>) genericDeclaration : null;
     }
 
+    /**
+     * Implementation for a parameterized type
+     *
+     * @opensearch.internal
+     */
     public static class ParameterizedTypeImpl implements ParameterizedType, CompositeType {
         private final Type ownerType;
         private final Type rawType;
@@ -510,6 +517,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Implementation for a generic array
+     *
+     * @opensearch.internal
+     */
     public static class GenericArrayTypeImpl implements GenericArrayType, CompositeType {
         private final Type componentType;
 
@@ -547,6 +559,8 @@ public String toString() {
      * The WildcardType interface supports multiple upper bounds and multiple
      * lower bounds. We only support what the Java 6 language needs - at most one
      * bound. If a lower bound is set, the upper bound must be Object.class.
+     *
+     * @opensearch.internal
      */
     public static class WildcardTypeImpl implements WildcardType, CompositeType {
         private final Type upperBound;
@@ -617,6 +631,8 @@ private static void checkNotPrimitive(Type type, String use) {
      * We cannot serialize the built-in Java member classes, which prevents us from using Members in
      * our exception types. We workaround this with this serializable implementation. It includes all
      * of the API methods, plus everything we use for line numbers and messaging.
+     *
+     * @opensearch.internal
      */
     public static class MemberImpl implements Member {
         private final Class<?> declaringClass;
@@ -661,6 +677,8 @@ public String toString() {
 
     /**
      * A type formed from other types, such as arrays, parameterized types or wildcard types
+     *
+     * @opensearch.internal
      */
     private interface CompositeType {
         /**
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Nullability.java b/server/src/main/java/org/opensearch/common/inject/internal/Nullability.java
index ecc7d5f9f5b3c..1f968adfe57ea 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Nullability.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Nullability.java
@@ -43,6 +43,8 @@
  * org.jetbrains.annotations.Nullable</a>.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class Nullability {
     private Nullability() {}
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/PrivateElementsImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/PrivateElementsImpl.java
index c8cd137bdf5fd..46caeeebc8cc6 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/PrivateElementsImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/PrivateElementsImpl.java
@@ -48,7 +48,11 @@
 import static java.util.Collections.unmodifiableMap;
 
 /**
+ * Private elements implementation
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public final class PrivateElementsImpl implements PrivateElements {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ProviderInstanceBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/ProviderInstanceBindingImpl.java
index 96f4b0644172a..b74429fe6728e 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ProviderInstanceBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ProviderInstanceBindingImpl.java
@@ -44,6 +44,11 @@
 
 import static java.util.Collections.unmodifiableSet;
 
+/**
+ * Provider instance binding
+ *
+ * @opensearch.internal
+ */
 public final class ProviderInstanceBindingImpl<T> extends BindingImpl<T> implements ProviderInstanceBinding<T> {
 
     final Provider<? extends T> providerInstance;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethod.java b/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethod.java
index 8acbc663aca7d..5368eaee7539a 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethod.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethod.java
@@ -47,6 +47,8 @@
  * A provider that invokes a method and returns its result.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class ProviderMethod<T> implements ProviderWithDependencies<T> {
     private final Key<T> key;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethodsModule.java b/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethodsModule.java
index e34a338fdc41e..0ca911d4d9be4 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethodsModule.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ProviderMethodsModule.java
@@ -56,6 +56,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public final class ProviderMethodsModule implements Module {
     private final Object delegate;
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Scoping.java b/server/src/main/java/org/opensearch/common/inject/internal/Scoping.java
index cda8d6e41a1ff..da0601fd9145f 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Scoping.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Scoping.java
@@ -43,6 +43,8 @@
  * The scope's eager or laziness is also exposed.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public abstract class Scoping {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/SourceProvider.java b/server/src/main/java/org/opensearch/common/inject/internal/SourceProvider.java
index 0ff1c6bef3566..e7e2afe35aa89 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/SourceProvider.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/SourceProvider.java
@@ -39,6 +39,8 @@
  * Provides access to the calling line of code.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class SourceProvider {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/StackTraceElements.java b/server/src/main/java/org/opensearch/common/inject/internal/StackTraceElements.java
index f0335639e9b34..2c0e67351dfdd 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/StackTraceElements.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/StackTraceElements.java
@@ -36,6 +36,8 @@
  * Creates stack trace elements for members.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class StackTraceElements {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Stopwatch.java b/server/src/main/java/org/opensearch/common/inject/internal/Stopwatch.java
index c35c4334fb609..61038306f48cc 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Stopwatch.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Stopwatch.java
@@ -37,6 +37,8 @@
  * Enables simple performance monitoring.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Stopwatch {
     private static final Logger logger = Logger.getLogger(Stopwatch.class.getName());
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/Strings.java b/server/src/main/java/org/opensearch/common/inject/internal/Strings.java
index 5ad1e96c319c4..97004ce6dd3ac 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/Strings.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/Strings.java
@@ -33,6 +33,8 @@
  * String utilities.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Strings {
     private Strings() {}
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/ToStringBuilder.java b/server/src/main/java/org/opensearch/common/inject/internal/ToStringBuilder.java
index 2953f2430df95..d9af76322297c 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/ToStringBuilder.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/ToStringBuilder.java
@@ -36,6 +36,8 @@
  * Helps with {@code toString()} methods.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class ToStringBuilder {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/UniqueAnnotations.java b/server/src/main/java/org/opensearch/common/inject/internal/UniqueAnnotations.java
index 6b5e859258c15..3c037f7cd552a 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/UniqueAnnotations.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/UniqueAnnotations.java
@@ -38,7 +38,11 @@
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
 /**
+ * Unique annotations.
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public class UniqueAnnotations {
     private UniqueAnnotations() {}
diff --git a/server/src/main/java/org/opensearch/common/inject/internal/UntargettedBindingImpl.java b/server/src/main/java/org/opensearch/common/inject/internal/UntargettedBindingImpl.java
index 9e2c148ec79ce..a4a472a061fee 100644
--- a/server/src/main/java/org/opensearch/common/inject/internal/UntargettedBindingImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/internal/UntargettedBindingImpl.java
@@ -36,6 +36,11 @@
 import org.opensearch.common.inject.spi.Dependency;
 import org.opensearch.common.inject.spi.UntargettedBinding;
 
+/**
+ * An untargeted binding implementation
+ *
+ * @opensearch.internal
+ */
 public class UntargettedBindingImpl<T> extends BindingImpl<T> implements UntargettedBinding<T> {
 
     public UntargettedBindingImpl(Injector injector, Key<T> key, Object source) {
diff --git a/server/src/main/java/org/opensearch/common/inject/matcher/AbstractMatcher.java b/server/src/main/java/org/opensearch/common/inject/matcher/AbstractMatcher.java
index c6c77cb62f46f..9d9c3ec490bec 100644
--- a/server/src/main/java/org/opensearch/common/inject/matcher/AbstractMatcher.java
+++ b/server/src/main/java/org/opensearch/common/inject/matcher/AbstractMatcher.java
@@ -33,6 +33,8 @@
  * Implements {@code and()} and {@code or()}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractMatcher<T> implements Matcher<T> {
 
@@ -46,6 +48,11 @@ public Matcher<T> or(Matcher<? super T> other) {
         return new OrMatcher<>(this, other);
     }
 
+    /**
+     * An AND matcher
+     *
+     * @opensearch.internal
+     */
     private static class AndMatcher<T> extends AbstractMatcher<T> {
         private final Matcher<? super T> a, b;
 
@@ -75,6 +82,11 @@ public String toString() {
         }
     }
 
+    /**
+     * An OR matcher
+     *
+     * @opensearch.internal
+     */
     private static class OrMatcher<T> extends AbstractMatcher<T> {
         private final Matcher<? super T> a, b;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/matcher/Matcher.java b/server/src/main/java/org/opensearch/common/inject/matcher/Matcher.java
index 090a8ef63fc57..21bb63cfef097 100644
--- a/server/src/main/java/org/opensearch/common/inject/matcher/Matcher.java
+++ b/server/src/main/java/org/opensearch/common/inject/matcher/Matcher.java
@@ -33,6 +33,8 @@
  * Returns {@code true} or {@code false} for a given input.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public interface Matcher<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/matcher/Matchers.java b/server/src/main/java/org/opensearch/common/inject/matcher/Matchers.java
index dd997e0168f09..e33e7f32ee5de 100644
--- a/server/src/main/java/org/opensearch/common/inject/matcher/Matchers.java
+++ b/server/src/main/java/org/opensearch/common/inject/matcher/Matchers.java
@@ -42,6 +42,8 @@
  * Matcher implementations. Supports matching classes and methods.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Matchers {
     private Matchers() {}
@@ -55,6 +57,11 @@ public static Matcher<Object> any() {
 
     private static final Matcher<Object> ANY = new Any();
 
+    /**
+     * Matches ANY
+     *
+     * @opensearch.internal
+     */
     private static class Any extends AbstractMatcher<Object> {
         @Override
         public boolean matches(Object o) {
@@ -78,6 +85,11 @@ public static <T> Matcher<T> not(final Matcher<? super T> p) {
         return new Not<>(p);
     }
 
+    /**
+     * A NOT Matcher
+     *
+     * @opensearch.internal
+     */
     private static class Not<T> extends AbstractMatcher<T> {
         final Matcher<? super T> delegate;
 
@@ -121,6 +133,11 @@ public static Matcher<AnnotatedElement> annotatedWith(final Class<? extends Anno
         return new AnnotatedWithType(annotationType);
     }
 
+    /**
+     * An annotated with type
+     *
+     * @opensearch.internal
+     */
     private static class AnnotatedWithType extends AbstractMatcher<AnnotatedElement> {
         private final Class<? extends Annotation> annotationType;
 
@@ -158,6 +175,11 @@ public static Matcher<AnnotatedElement> annotatedWith(final Annotation annotatio
         return new AnnotatedWith(annotation);
     }
 
+    /**
+     * An annotated With matcher
+     *
+     * @opensearch.internal
+     */
     private static class AnnotatedWith extends AbstractMatcher<AnnotatedElement> {
         private final Annotation annotation;
 
@@ -196,6 +218,11 @@ public static Matcher<Class> subclassesOf(final Class<?> superclass) {
         return new SubclassesOf(superclass);
     }
 
+    /**
+     * A subclass matcher
+     *
+     * @opensearch.internal
+     */
     private static class SubclassesOf extends AbstractMatcher<Class> {
         private final Class<?> superclass;
 
@@ -231,6 +258,11 @@ public static Matcher<Object> only(Object value) {
         return new Only(value);
     }
 
+    /**
+     * ONLY matcher
+     *
+     * @opensearch.internal
+     */
     private static class Only extends AbstractMatcher<Object> {
         private final Object value;
 
@@ -266,6 +298,11 @@ public static Matcher<Object> identicalTo(final Object value) {
         return new IdenticalTo(value);
     }
 
+    /**
+     * Identical matcher
+     *
+     * @opensearch.internal
+     */
     private static class IdenticalTo extends AbstractMatcher<Object> {
         private final Object value;
 
@@ -302,6 +339,11 @@ public static Matcher<Class> inPackage(final Package targetPackage) {
         return new InPackage(targetPackage);
     }
 
+    /**
+     * In Package matcher
+     *
+     * @opensearch.internal
+     */
     private static class InPackage extends AbstractMatcher<Class> {
         private final transient Package targetPackage;
         private final String packageName;
@@ -348,6 +390,11 @@ public static Matcher<Class> inSubpackage(final String targetPackageName) {
         return new InSubpackage(targetPackageName);
     }
 
+    /**
+     * In Subpackage matcher
+     *
+     * @opensearch.internal
+     */
     private static class InSubpackage extends AbstractMatcher<Class> {
         private final String targetPackageName;
 
@@ -384,6 +431,11 @@ public static Matcher<Method> returns(final Matcher<? super Class<?>> returnType
         return new Returns(returnType);
     }
 
+    /**
+     * Returns matcher
+     *
+     * @opensearch.internal
+     */
     private static class Returns extends AbstractMatcher<Method> {
         private final Matcher<? super Class<?>> returnType;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/multibindings/Element.java b/server/src/main/java/org/opensearch/common/inject/multibindings/Element.java
index f1dae7da4ae1c..c0c1dc02f51be 100644
--- a/server/src/main/java/org/opensearch/common/inject/multibindings/Element.java
+++ b/server/src/main/java/org/opensearch/common/inject/multibindings/Element.java
@@ -41,6 +41,8 @@
  * to contribute multibindings independently.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 @Retention(RUNTIME)
 @BindingAnnotation
diff --git a/server/src/main/java/org/opensearch/common/inject/multibindings/MapBinder.java b/server/src/main/java/org/opensearch/common/inject/multibindings/MapBinder.java
index 734d6da15a2ab..e8d984fce3d48 100644
--- a/server/src/main/java/org/opensearch/common/inject/multibindings/MapBinder.java
+++ b/server/src/main/java/org/opensearch/common/inject/multibindings/MapBinder.java
@@ -106,6 +106,8 @@
  * will not).
  *
  * @author dpb@google.com (David P. Baker)
+ *
+ * @opensearch.internal
  */
 public abstract class MapBinder<K, V> {
     private MapBinder() {}
@@ -299,6 +301,11 @@ public LinkedBindingBuilder<V> addBinding(K key) {
             return binder.bind(valueKey);
         }
 
+        /**
+         * A binder provider with dependencies
+         *
+         * @opensearch.internal
+         */
         public static class MapBinderProviderWithDependencies<K, V> implements ProviderWithDependencies<Map<K, Provider<V>>> {
             private Map<K, Provider<V>> providerMap;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/multibindings/Multibinder.java b/server/src/main/java/org/opensearch/common/inject/multibindings/Multibinder.java
index 6cd9fbc46d544..09e3a0ea9842c 100644
--- a/server/src/main/java/org/opensearch/common/inject/multibindings/Multibinder.java
+++ b/server/src/main/java/org/opensearch/common/inject/multibindings/Multibinder.java
@@ -102,6 +102,8 @@
  * set injection will fail.
  *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 public abstract class Multibinder<T> {
     private Multibinder() {}
diff --git a/server/src/main/java/org/opensearch/common/inject/multibindings/RealElement.java b/server/src/main/java/org/opensearch/common/inject/multibindings/RealElement.java
index 7603df43c9d9a..1363103fdd21e 100644
--- a/server/src/main/java/org/opensearch/common/inject/multibindings/RealElement.java
+++ b/server/src/main/java/org/opensearch/common/inject/multibindings/RealElement.java
@@ -33,7 +33,11 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
+ * A real element.
+ *
  * @author jessewilson@google.com (Jesse Wilson)
+ *
+ * @opensearch.internal
  */
 class RealElement implements Element {
     private static final AtomicInteger nextUniqueId = new AtomicInteger(1);
diff --git a/server/src/main/java/org/opensearch/common/inject/name/Named.java b/server/src/main/java/org/opensearch/common/inject/name/Named.java
index ddc1065cdcadd..3972c2f631d58 100644
--- a/server/src/main/java/org/opensearch/common/inject/name/Named.java
+++ b/server/src/main/java/org/opensearch/common/inject/name/Named.java
@@ -41,6 +41,8 @@
  * Annotates named things.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 @Retention(RUNTIME)
 @Target({ ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD })
diff --git a/server/src/main/java/org/opensearch/common/inject/name/NamedImpl.java b/server/src/main/java/org/opensearch/common/inject/name/NamedImpl.java
index b15ffd073e270..beed8be7218ac 100644
--- a/server/src/main/java/org/opensearch/common/inject/name/NamedImpl.java
+++ b/server/src/main/java/org/opensearch/common/inject/name/NamedImpl.java
@@ -32,6 +32,11 @@
 import java.lang.annotation.Annotation;
 import java.util.Objects;
 
+/**
+ * A named implementation
+ *
+ * @opensearch.internal
+ */
 class NamedImpl implements Named {
 
     private final String value;
diff --git a/server/src/main/java/org/opensearch/common/inject/name/Names.java b/server/src/main/java/org/opensearch/common/inject/name/Names.java
index 8de65534baffd..1de439f2cfbfd 100644
--- a/server/src/main/java/org/opensearch/common/inject/name/Names.java
+++ b/server/src/main/java/org/opensearch/common/inject/name/Names.java
@@ -40,6 +40,8 @@
  * Utility methods for use with {@code @}{@link Named}.
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public class Names {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/BindingScopingVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/BindingScopingVisitor.java
index 596ec0df01063..d7c7d9d65051d 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/BindingScopingVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/BindingScopingVisitor.java
@@ -39,6 +39,8 @@
  * @param <V> any type to be returned by the visit method. Use {@link Void} with
  *            {@code return null} if no return type is needed.
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface BindingScopingVisitor<V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/BindingTargetVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/BindingTargetVisitor.java
index 2633245f804a8..91df812b58ac4 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/BindingTargetVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/BindingTargetVisitor.java
@@ -35,6 +35,8 @@
  * @param <V> any type to be returned by the visit method. Use {@link Void} with
  *            {@code return null} if no return type is needed.
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface BindingTargetVisitor<T, V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ConstructorBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ConstructorBinding.java
index 22e7d763e97b5..997bf78234fd1 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ConstructorBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ConstructorBinding.java
@@ -39,6 +39,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ConstructorBinding<T> extends Binding<T>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ConvertedConstantBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ConvertedConstantBinding.java
index 9b5242298ac74..e8d6b346f8596 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ConvertedConstantBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ConvertedConstantBinding.java
@@ -40,6 +40,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ConvertedConstantBinding<T> extends Binding<T>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingScopingVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingScopingVisitor.java
index f4744525bedf1..8fa5610e899bb 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingScopingVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingScopingVisitor.java
@@ -41,6 +41,8 @@
  *            {@code return null} if no return type is needed.
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public class DefaultBindingScopingVisitor<V> implements BindingScopingVisitor<V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingTargetVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingTargetVisitor.java
index 9ac3413155c15..f66199736740f 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingTargetVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/DefaultBindingTargetVisitor.java
@@ -39,6 +39,8 @@
  *            {@code return null} if no return type is needed.
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public abstract class DefaultBindingTargetVisitor<T, V> implements BindingTargetVisitor<T, V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/DefaultElementVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/DefaultElementVisitor.java
index 5196fa68a88a6..01568e56242dc 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/DefaultElementVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/DefaultElementVisitor.java
@@ -39,6 +39,8 @@
  *            {@code return null} if no return type is needed.
  * @author sberlin@gmail.com (Sam Berlin)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public abstract class DefaultElementVisitor<V> implements ElementVisitor<V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/Dependency.java b/server/src/main/java/org/opensearch/common/inject/spi/Dependency.java
index 99158a4432067..be1336ad0f297 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/Dependency.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/Dependency.java
@@ -46,6 +46,8 @@
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class Dependency<T> {
     private final InjectionPoint injectionPoint;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/Element.java b/server/src/main/java/org/opensearch/common/inject/spi/Element.java
index 3f30a2643b48f..660aca1bd45ab 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/Element.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/Element.java
@@ -42,6 +42,8 @@
  * @author jessewilson@google.com (Jesse Wilson)
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ElementVisitor.java b/server/src/main/java/org/opensearch/common/inject/spi/ElementVisitor.java
index f6cbc39d5edcf..d415560fc03c8 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ElementVisitor.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ElementVisitor.java
@@ -37,6 +37,8 @@
  * @param <V> any type to be returned by the visit method. Use {@link Void} with
  *            {@code return null} if no return type is needed.
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ElementVisitor<V> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/Elements.java b/server/src/main/java/org/opensearch/common/inject/spi/Elements.java
index 9ae2877e8b78d..21dcc9ba54920 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/Elements.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/Elements.java
@@ -70,6 +70,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class Elements {
 
@@ -112,6 +114,11 @@ public void configure(Binder binder) {
         };
     }
 
+    /**
+     * A recording binder
+     *
+     * @opensearch.internal
+     */
     private static class RecordingBinder implements Binder, PrivateBinder {
         private final Stage stage;
         private final Set<Module> modules;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ExposedBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ExposedBinding.java
index 42afd5377396c..d2563bc2728cd 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ExposedBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ExposedBinding.java
@@ -37,6 +37,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ExposedBinding<T> extends Binding<T>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/HasDependencies.java b/server/src/main/java/org/opensearch/common/inject/spi/HasDependencies.java
index 51141bea2a066..b142197fb7126 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/HasDependencies.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/HasDependencies.java
@@ -37,6 +37,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/InjectionListener.java b/server/src/main/java/org/opensearch/common/inject/spi/InjectionListener.java
index aab5d65188f9a..7a760d2b84e9f 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/InjectionListener.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/InjectionListener.java
@@ -36,6 +36,8 @@
  * @author crazybob@google.com (Bob Lee)
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface InjectionListener<I> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/InjectionPoint.java b/server/src/main/java/org/opensearch/common/inject/spi/InjectionPoint.java
index 36c145433c0d4..c88b2281107ed 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/InjectionPoint.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/InjectionPoint.java
@@ -65,6 +65,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class InjectionPoint {
 
@@ -404,6 +406,11 @@ private static boolean isStatic(Member member) {
         return Modifier.isStatic(member.getModifiers());
     }
 
+    /**
+     * Factory for the injection point
+     *
+     * @opensearch.internal
+     */
     private interface Factory<M extends Member & AnnotatedElement> {
         Factory<Field> FIELDS = new Factory<Field>() {
             @Override
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/InjectionRequest.java b/server/src/main/java/org/opensearch/common/inject/spi/InjectionRequest.java
index bc15e00c12089..6ce5febbb6711 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/InjectionRequest.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/InjectionRequest.java
@@ -45,6 +45,8 @@
  *
  * @author mikeward@google.com (Mike Ward)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class InjectionRequest<T> implements Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/InstanceBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/InstanceBinding.java
index 6db9caa209bf1..fd7c1303ed6fc 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/InstanceBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/InstanceBinding.java
@@ -38,6 +38,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface InstanceBinding<T> extends Binding<T>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/LinkedKeyBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/LinkedKeyBinding.java
index 046c28f8d9340..10b270e499603 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/LinkedKeyBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/LinkedKeyBinding.java
@@ -37,6 +37,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface LinkedKeyBinding<T> extends Binding<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/MembersInjectorLookup.java b/server/src/main/java/org/opensearch/common/inject/spi/MembersInjectorLookup.java
index d85d49ae8dd36..1f652708de875 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/MembersInjectorLookup.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/MembersInjectorLookup.java
@@ -44,6 +44,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class MembersInjectorLookup<T> implements Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/Message.java b/server/src/main/java/org/opensearch/common/inject/spi/Message.java
index b47eb787c737d..78829e82c150e 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/Message.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/Message.java
@@ -49,6 +49,8 @@
  *     }</pre>
  *
  * @author crazybob@google.com (Bob Lee)
+ *
+ * @opensearch.internal
  */
 public final class Message implements Element {
     private final String message;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/PrivateElements.java b/server/src/main/java/org/opensearch/common/inject/spi/PrivateElements.java
index badcc273359ea..e4d86a356cd53 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/PrivateElements.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/PrivateElements.java
@@ -41,6 +41,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface PrivateElements extends Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ProviderBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ProviderBinding.java
index e2fa36741517c..0a63fefc0a9e9 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ProviderBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ProviderBinding.java
@@ -39,6 +39,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ProviderBinding<T extends Provider<?>> extends Binding<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ProviderInstanceBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ProviderInstanceBinding.java
index 8245f6cb65ab1..654f40e627e4b 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ProviderInstanceBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ProviderInstanceBinding.java
@@ -40,6 +40,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ProviderInstanceBinding<T> extends Binding<T>, HasDependencies {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ProviderKeyBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ProviderKeyBinding.java
index 92004d8d5c60e..6f1ae8f2b9a03 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ProviderKeyBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ProviderKeyBinding.java
@@ -39,6 +39,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ProviderKeyBinding<T> extends Binding<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ProviderLookup.java b/server/src/main/java/org/opensearch/common/inject/spi/ProviderLookup.java
index 190a8b14cf168..16060ddd3e222 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ProviderLookup.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ProviderLookup.java
@@ -44,9 +44,16 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class ProviderLookup<T> implements Element {
 
+    /**
+     * A provider implementation
+     *
+     * @opensearch.internal
+     */
     // NOTE: this class is not part of guice and was added so the provider lookup's key can be accessible for tests
     public static class ProviderImpl<T> implements Provider<T> {
         private ProviderLookup<T> lookup;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ProviderWithDependencies.java b/server/src/main/java/org/opensearch/common/inject/spi/ProviderWithDependencies.java
index 2f5485c23c956..6c450095a310b 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ProviderWithDependencies.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ProviderWithDependencies.java
@@ -36,5 +36,7 @@
  * aren't specified in injections, this interface should be used to expose all dependencies.
  *
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface ProviderWithDependencies<T> extends Provider<T>, HasDependencies {}
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/ScopeBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/ScopeBinding.java
index 26b611e656ed0..7a619456e06e3 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/ScopeBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/ScopeBinding.java
@@ -45,6 +45,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class ScopeBinding implements Element {
     private final Object source;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/StaticInjectionRequest.java b/server/src/main/java/org/opensearch/common/inject/spi/StaticInjectionRequest.java
index 64dc3d15a505c..494e35e6c4490 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/StaticInjectionRequest.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/StaticInjectionRequest.java
@@ -44,6 +44,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class StaticInjectionRequest implements Element {
     private final Object source;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/TypeConverter.java b/server/src/main/java/org/opensearch/common/inject/spi/TypeConverter.java
index 3b748b3eb1be1..93a0f607ddc27 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/TypeConverter.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/TypeConverter.java
@@ -36,6 +36,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface TypeConverter {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/TypeConverterBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/TypeConverterBinding.java
index 66bfa472e72a3..00b8c7c013b5a 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/TypeConverterBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/TypeConverterBinding.java
@@ -44,6 +44,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class TypeConverterBinding implements Element {
     private final Object source;
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/TypeEncounter.java b/server/src/main/java/org/opensearch/common/inject/spi/TypeEncounter.java
index 9db116db6bedb..e06751668c0f1 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/TypeEncounter.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/TypeEncounter.java
@@ -42,6 +42,8 @@
  *
  * @param <I> the injectable type encountered
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 @SuppressWarnings("overloads")
 public interface TypeEncounter<I> {
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/TypeListener.java b/server/src/main/java/org/opensearch/common/inject/spi/TypeListener.java
index 720766f2a4dc4..fd7004aa80df0 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/TypeListener.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/TypeListener.java
@@ -42,6 +42,8 @@
  * binding method interceptors}.
  *
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface TypeListener {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/TypeListenerBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/TypeListenerBinding.java
index 84d78698268df..505028f09232d 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/TypeListenerBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/TypeListenerBinding.java
@@ -41,6 +41,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class TypeListenerBinding implements Element {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/spi/UntargettedBinding.java b/server/src/main/java/org/opensearch/common/inject/spi/UntargettedBinding.java
index 940706aaffbe6..37e40d45cb5a9 100644
--- a/server/src/main/java/org/opensearch/common/inject/spi/UntargettedBinding.java
+++ b/server/src/main/java/org/opensearch/common/inject/spi/UntargettedBinding.java
@@ -37,5 +37,7 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public interface UntargettedBinding<T> extends Binding<T> {}
diff --git a/server/src/main/java/org/opensearch/common/inject/util/Modules.java b/server/src/main/java/org/opensearch/common/inject/util/Modules.java
index c4461b893b75a..ae37cb3d29a68 100644
--- a/server/src/main/java/org/opensearch/common/inject/util/Modules.java
+++ b/server/src/main/java/org/opensearch/common/inject/util/Modules.java
@@ -60,6 +60,8 @@
  *
  * @author jessewilson@google.com (Jesse Wilson)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class Modules {
     private Modules() {}
@@ -128,6 +130,8 @@ public void configure(Binder binder) {
 
     /**
      * See the EDSL example at {@link Modules#override(Module[]) override()}.
+     *
+     * @opensearch.internal
      */
     public interface OverriddenModuleBuilder {
 
@@ -277,6 +281,11 @@ public Scope visitScope(Scope scope) {
         }
     }
 
+    /**
+     * A module writer
+     *
+     * @opensearch.internal
+     */
     private static class ModuleWriter extends DefaultElementVisitor<Void> {
         protected final Binder binder;
 
diff --git a/server/src/main/java/org/opensearch/common/inject/util/Providers.java b/server/src/main/java/org/opensearch/common/inject/util/Providers.java
index d7444e9b60e73..8eb46885e2967 100644
--- a/server/src/main/java/org/opensearch/common/inject/util/Providers.java
+++ b/server/src/main/java/org/opensearch/common/inject/util/Providers.java
@@ -37,6 +37,8 @@
  *
  * @author Kevin Bourrillion (kevinb9n@gmail.com)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class Providers {
 
diff --git a/server/src/main/java/org/opensearch/common/inject/util/Types.java b/server/src/main/java/org/opensearch/common/inject/util/Types.java
index 01f0385602222..82f8190ebc22d 100644
--- a/server/src/main/java/org/opensearch/common/inject/util/Types.java
+++ b/server/src/main/java/org/opensearch/common/inject/util/Types.java
@@ -48,6 +48,8 @@
  *
  * @author crazybob@google.com (Bob Lee)
  * @since 2.0
+ *
+ * @opensearch.internal
  */
 public final class Types {
     private Types() {}
diff --git a/server/src/main/java/org/opensearch/common/io/Channels.java b/server/src/main/java/org/opensearch/common/io/Channels.java
index 3880d4dbf19aa..29f50b117234d 100644
--- a/server/src/main/java/org/opensearch/common/io/Channels.java
+++ b/server/src/main/java/org/opensearch/common/io/Channels.java
@@ -40,6 +40,11 @@
 import java.nio.channels.FileChannel;
 import java.nio.channels.WritableByteChannel;
 
+/**
+ * Data channels
+ *
+ * @opensearch.internal
+ */
 @SuppressForbidden(reason = "Channel#read")
 public final class Channels {
 
diff --git a/server/src/main/java/org/opensearch/common/io/DiskIoBufferPool.java b/server/src/main/java/org/opensearch/common/io/DiskIoBufferPool.java
index 73fc09f6683b4..e853a6ddc34d2 100644
--- a/server/src/main/java/org/opensearch/common/io/DiskIoBufferPool.java
+++ b/server/src/main/java/org/opensearch/common/io/DiskIoBufferPool.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.common.io;
 
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
+/**
+ * Pool of disk io buffers
+ *
+ * @opensearch.internal
+ */
 public class DiskIoBufferPool {
 
     public static final int BUFFER_SIZE = StrictMath.toIntExact(
diff --git a/server/src/main/java/org/opensearch/common/io/IndexIOStreamHandler.java b/server/src/main/java/org/opensearch/common/io/IndexIOStreamHandler.java
new file mode 100644
index 0000000000000..34e0c0fea2093
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/io/IndexIOStreamHandler.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.io;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+
+import java.io.IOException;
+
+/**
+ * Interface for reading/writing content streams to/from - {@link T}
+ * @param <T> The type of content to be read/written to stream
+ *
+ * @opensearch.internal
+ */
+public interface IndexIOStreamHandler<T> {
+    /**
+     * Implements logic to read content from file input stream {@code indexInput} and parse into {@link T}
+     * @param indexInput file input stream
+     * @return content parsed to {@link T}
+     */
+    T readContent(IndexInput indexInput) throws IOException;
+
+    /**
+     * Implements logic to write content from {@code content} to file output stream {@code indexOutput}
+     * @param indexOutput file input stream
+     */
+    void writeContent(IndexOutput indexOutput, T content) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/common/io/Streams.java b/server/src/main/java/org/opensearch/common/io/Streams.java
index 5d347e636935b..f0d8f8b8bedbf 100644
--- a/server/src/main/java/org/opensearch/common/io/Streams.java
+++ b/server/src/main/java/org/opensearch/common/io/Streams.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.common.io;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.BytesStream;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.BufferedReader;
 import java.io.FilterInputStream;
@@ -59,6 +59,8 @@
  * <p>
  * Mainly for use within the framework,
  * but also useful for application code.
+ *
+ * @opensearch.internal
  */
 public abstract class Streams {
 
@@ -160,43 +162,16 @@ public static String copyToString(Reader in) throws IOException {
         return out.toString();
     }
 
-    public static int readFully(Reader reader, char[] dest) throws IOException {
-        return readFully(reader, dest, 0, dest.length);
-    }
-
-    public static int readFully(Reader reader, char[] dest, int offset, int len) throws IOException {
-        int read = 0;
-        while (read < len) {
-            final int r = reader.read(dest, offset + read, len - read);
-            if (r == -1) {
-                break;
-            }
-            read += r;
-        }
-        return read;
-    }
-
+    @Deprecated
     public static int readFully(InputStream reader, byte[] dest) throws IOException {
-        return readFully(reader, dest, 0, dest.length);
-    }
-
-    public static int readFully(InputStream reader, byte[] dest, int offset, int len) throws IOException {
-        int read = 0;
-        while (read < len) {
-            final int r = reader.read(dest, offset + read, len - read);
-            if (r == -1) {
-                break;
-            }
-            read += r;
-        }
-        return read;
+        return reader.readNBytes(dest, 0, dest.length);
     }
 
     /**
      * Fully consumes the input stream, throwing the bytes away. Returns the number of bytes consumed.
      */
     public static long consumeFully(InputStream inputStream) throws IOException {
-        return org.opensearch.core.internal.io.Streams.copy(inputStream, NULL_OUTPUT_STREAM);
+        return org.opensearch.common.util.io.Streams.copy(inputStream, NULL_OUTPUT_STREAM);
     }
 
     public static List<String> readAllLines(InputStream input) throws IOException {
@@ -242,7 +217,7 @@ public static BytesStream flushOnCloseStream(BytesStream os) {
      */
     public static BytesReference readFully(InputStream in) throws IOException {
         BytesStreamOutput out = new BytesStreamOutput();
-        org.opensearch.core.internal.io.Streams.copy(in, out);
+        org.opensearch.common.util.io.Streams.copy(in, out);
         return out.bytes();
     }
 
@@ -257,6 +232,8 @@ public static InputStream limitStream(InputStream in, long limit) {
      * A wrapper around a {@link BytesStream} that makes the close operation a flush. This is
      * needed as sometimes a stream will be closed but the bytes that the stream holds still need
      * to be used and the stream cannot be closed until the bytes have been consumed.
+     *
+     * @opensearch.internal
      */
     private static class FlushOnCloseOutputStream extends BytesStream {
 
@@ -299,6 +276,8 @@ public BytesReference bytes() {
 
     /**
      * A wrapper around an {@link InputStream} that limits the number of bytes that can be read from the stream.
+     *
+     * @opensearch.internal
      */
     static class LimitedInputStream extends FilterInputStream {
 
diff --git a/server/src/main/java/org/opensearch/common/io/UTF8StreamWriter.java b/server/src/main/java/org/opensearch/common/io/UTF8StreamWriter.java
index f8f90f290358b..4c299d7c10a92 100644
--- a/server/src/main/java/org/opensearch/common/io/UTF8StreamWriter.java
+++ b/server/src/main/java/org/opensearch/common/io/UTF8StreamWriter.java
@@ -37,6 +37,11 @@
 import java.io.OutputStream;
 import java.io.Writer;
 
+/**
+ * UTF8 Stream Writer.
+ *
+ * @opensearch.internal
+ */
 public final class UTF8StreamWriter extends Writer {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/io/VersionedCodecStreamWrapper.java b/server/src/main/java/org/opensearch/common/io/VersionedCodecStreamWrapper.java
new file mode 100644
index 0000000000000..8089d354a2480
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/io/VersionedCodecStreamWrapper.java
@@ -0,0 +1,127 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.io;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.store.ChecksumIndexInput;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+
+import java.io.IOException;
+
+/**
+ * Manages versioning and checksum for a stream of content.
+ * @param <T> Type of content to be read/written
+ *
+ * @opensearch.internal
+ */
+public class VersionedCodecStreamWrapper<T> {
+    private static final Logger logger = LogManager.getLogger(VersionedCodecStreamWrapper.class);
+
+    // TODO This can be updated to hold a streamReadWriteHandlerFactory and get relevant handler based on the stream versions
+    private final IndexIOStreamHandler<T> indexIOStreamHandler;
+    private final int currentVersion;
+    private final String codec;
+
+    /**
+     * @param indexIOStreamHandler handler to read/write stream from T
+     * @param currentVersion latest supported version of the stream
+     * @param codec: stream codec
+     */
+    public VersionedCodecStreamWrapper(IndexIOStreamHandler<T> indexIOStreamHandler, int currentVersion, String codec) {
+        this.indexIOStreamHandler = indexIOStreamHandler;
+        this.currentVersion = currentVersion;
+        this.codec = codec;
+    }
+
+    /**
+     * Reads stream content from {@code indexInput} and parses the read content to {@link T}.
+     * Before reading actual content, verifies the header with relevant codec and version.
+     * After reading the actual content, verifies the checksum as well
+     * @param indexInput file input stream
+     * @return stream content parsed into {@link T}
+     */
+    public T readStream(IndexInput indexInput) throws IOException {
+        logger.debug("Reading input stream [{}] of length - [{}]", indexInput.toString(), indexInput.length());
+        try {
+            CodecUtil.checksumEntireFile(indexInput);
+            int readStreamVersion = checkHeader(indexInput);
+            return getHandlerForVersion(readStreamVersion).readContent(indexInput);
+        } catch (CorruptIndexException cie) {
+            logger.error(
+                () -> new ParameterizedMessage(
+                    "Error while validating header/footer for [{}]. Total data length [{}]",
+                    indexInput.toString(),
+                    indexInput.length()
+                )
+            );
+            throw cie;
+        }
+    }
+
+    /**
+     * Writes to file output stream {@code indexOutput}
+     * @param indexOutput file output stream which will store stream content
+     * @param content stream content.
+     */
+    public void writeStream(IndexOutput indexOutput, T content) throws IOException {
+        this.writeHeader(indexOutput);
+        getHandlerForVersion(this.currentVersion).writeContent(indexOutput, content);
+        this.writeFooter(indexOutput);
+    }
+
+    /**
+     * Reads header from file input stream containing {@code this.codec} and {@code this.currentVersion}.
+     * @param indexInput file input stream
+     * @return header version found in the input stream
+     */
+    private int checkHeader(IndexInput indexInput) throws IOException {
+        // TODO Once versioning strategy is decided we'll add support for min/max supported versions
+        return CodecUtil.checkHeader(indexInput, this.codec, this.currentVersion, this.currentVersion);
+    }
+
+    /**
+     * Reads footer from file input stream containing checksum.
+     * The {@link IndexInput#getFilePointer()} should be at the footer start position.
+     * @param indexInput file input stream
+     */
+    private void checkFooter(ChecksumIndexInput indexInput) throws IOException {
+        CodecUtil.checkFooter(indexInput);
+    }
+
+    /**
+     * Writes header with {@code this.codec} and {@code this.currentVersion} to the file output stream
+     * @param indexOutput file output stream
+     */
+    private void writeHeader(IndexOutput indexOutput) throws IOException {
+        CodecUtil.writeHeader(indexOutput, this.codec, this.currentVersion);
+    }
+
+    /**
+     * Writes footer with checksum of contents of file output stream
+     * @param indexOutput file output stream
+     */
+    private void writeFooter(IndexOutput indexOutput) throws IOException {
+        CodecUtil.writeFooter(indexOutput);
+    }
+
+    /**
+     * Returns relevant handler for the version
+     * @param version stream content version
+     */
+    private IndexIOStreamHandler<T> getHandlerForVersion(int version) {
+        // TODO implement factory and pick relevant handler based on version.
+        // It should also take into account min and max supported versions
+        return this.indexIOStreamHandler;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/io/package-info.java b/server/src/main/java/org/opensearch/common/io/package-info.java
new file mode 100644
index 0000000000000..28e34bcead549
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/io/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base IO package. */
+package org.opensearch.common.io;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/BytesStreamOutput.java b/server/src/main/java/org/opensearch/common/io/stream/BytesStreamOutput.java
index 22c37ab476a73..ad09efde72009 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/BytesStreamOutput.java
+++ b/server/src/main/java/org/opensearch/common/io/stream/BytesStreamOutput.java
@@ -35,17 +35,21 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.ByteArray;
 
 import java.io.IOException;
 
 /**
  * A @link {@link StreamOutput} that uses {@link BigArrays} to acquire pages of
  * bytes, which avoids frequent reallocation &amp; copying of the internal data.
+ *
+ * @opensearch.internal
  */
 public class BytesStreamOutput extends BytesStream {
 
@@ -187,8 +191,8 @@ public BytesReference copyBytes() {
     }
 
     /**
-     * Returns the number of bytes used by the underlying {@link org.opensearch.common.util.ByteArray}
-     * @see org.opensearch.common.util.ByteArray#ramBytesUsed()
+     * Returns the number of bytes used by the underlying {@link ByteArray}
+     * @see ByteArray#ramBytesUsed()
      */
     public long ramBytesUsed() {
         return bytes.ramBytesUsed();
diff --git a/server/src/main/java/org/opensearch/common/io/stream/DelayableWriteable.java b/server/src/main/java/org/opensearch/common/io/stream/DelayableWriteable.java
index a4dddaf1f172a..200f3e9225834 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/DelayableWriteable.java
+++ b/server/src/main/java/org/opensearch/common/io/stream/DelayableWriteable.java
@@ -35,7 +35,12 @@
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -56,6 +61,8 @@
  * to delayed expansion). When such objects are buffered for some time it may be desirable
  * to force their buffering in serialized format by calling
  * {@link #asSerialized(Reader, NamedWriteableRegistry)}.
+ *
+ * @opensearch.internal
  */
 public abstract class DelayableWriteable<T extends Writeable> implements Writeable {
     /**
@@ -94,6 +101,11 @@ private DelayableWriteable() {}
      */
     abstract boolean isSerialized();
 
+    /**
+     * A referencing writable
+     *
+     * @opensearch.internal
+     */
     private static class Referencing<T extends Writeable> extends DelayableWriteable<T> {
         private final T reference;
 
@@ -138,6 +150,8 @@ private BytesStreamOutput writeToBuffer(Version version) throws IOException {
 
     /**
      * A {@link Writeable} stored in serialized form.
+     *
+     * @opensearch.internal
      */
     public static class Serialized<T extends Writeable> extends DelayableWriteable<T> implements Accountable {
         private final Writeable.Reader<T> reader;
diff --git a/server/src/main/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutput.java b/server/src/main/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutput.java
index 35d5aac182f81..0fd8640305326 100644
--- a/server/src/main/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutput.java
+++ b/server/src/main/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutput.java
@@ -46,6 +46,8 @@
  * {@link ReleasableBytesReference} returned from {@link #bytes()}, so this
  * stream should only be closed after the bytes have been output or copied
  * elsewhere.
+ *
+ * @opensearch.internal
  */
 public class ReleasableBytesStreamOutput extends BytesStreamOutput implements Releasable {
 
diff --git a/server/src/main/java/org/opensearch/common/io/stream/Streamables.java b/server/src/main/java/org/opensearch/common/io/stream/Streamables.java
new file mode 100644
index 0000000000000..1e5f8164e8fb9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/io/stream/Streamables.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.io.stream;
+
+import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.time.DateUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable.WriteableRegistry;
+import org.opensearch.script.JodaCompatibleZonedDateTime;
+import org.joda.time.DateTimeZone;
+import org.joda.time.ReadableInstant;
+
+import java.time.Instant;
+import java.time.ZoneId;
+
+/**
+ * This utility class registers generic types for streaming over the wire using
+ * {@linkplain StreamOutput#writeGenericValue(Object)} and {@linkplain StreamInput#readGenericValue()}
+ *
+ * In this manner we can register any type across OpenSearch modules, plugins, or libraries without requiring
+ * the implementation reside in the server module.
+ *
+ * @opensearch.internal
+ */
+public final class Streamables {
+
+    // no instance:
+    private Streamables() {}
+
+    /**
+     * Called when {@linkplain org.opensearch.transport.TransportService} is loaded by the classloader
+     * We do this because streamables depend on the TransportService being loaded
+     */
+    public static void registerStreamables() {
+        registerWriters();
+        registerReaders();
+    }
+
+    /**
+     * Registers writers by class type
+     */
+    private static void registerWriters() {
+        /** {@link ReadableInstant} */
+        WriteableRegistry.registerWriter(ReadableInstant.class, (o, v) -> {
+            o.writeByte((byte) 13);
+            final ReadableInstant instant = (ReadableInstant) v;
+            o.writeString(instant.getZone().getID());
+            o.writeLong(instant.getMillis());
+        });
+        WriteableRegistry.registerClassAlias(ReadableInstant.class, ReadableInstant.class);
+        /** {@link JodaCompatibleZonedDateTime} */
+        WriteableRegistry.registerWriter(JodaCompatibleZonedDateTime.class, (o, v) -> {
+            // write the joda compatibility datetime as joda datetime
+            o.writeByte((byte) 13);
+            final JodaCompatibleZonedDateTime zonedDateTime = (JodaCompatibleZonedDateTime) v;
+            String zoneId = zonedDateTime.getZonedDateTime().getZone().getId();
+            // joda does not understand "Z" for utc, so we must special case
+            o.writeString(zoneId.equals("Z") ? DateTimeZone.UTC.getID() : zoneId);
+            o.writeLong(zonedDateTime.toInstant().toEpochMilli());
+        });
+        /** {@link GeoPoint} */
+        WriteableRegistry.registerWriter(GeoPoint.class, (o, v) -> {
+            o.writeByte((byte) 22);
+            ((GeoPoint) v).writeTo(o);
+        });
+    }
+
+    /**
+     * Registers a reader function mapped by ordinal values that are written by {@linkplain StreamOutput}
+     *
+     * NOTE: see {@code StreamOutput#WRITERS} for all registered ordinals
+     */
+    private static void registerReaders() {
+        /** {@link JodaCompatibleZonedDateTime */
+        WriteableRegistry.registerReader(Byte.valueOf((byte) 13), (i) -> {
+            final ZoneId zoneId = DateUtils.dateTimeZoneToZoneId(DateTimeZone.forID(i.readString()));
+            long millis = i.readLong();
+            return new JodaCompatibleZonedDateTime(Instant.ofEpochMilli(millis), zoneId);
+        });
+        /** {@link GeoPoint} */
+        WriteableRegistry.registerReader(Byte.valueOf((byte) 22), GeoPoint::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/io/stream/Writeable.java b/server/src/main/java/org/opensearch/common/io/stream/Writeable.java
deleted file mode 100644
index 253609cbaca77..0000000000000
--- a/server/src/main/java/org/opensearch/common/io/stream/Writeable.java
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.io.stream;
-
-import java.io.IOException;
-
-/**
- * Implementers can be written to a {@linkplain StreamOutput} and read from a {@linkplain StreamInput}. This allows them to be "thrown
- * across the wire" using OpenSearch's internal protocol. If the implementer also implements equals and hashCode then a copy made by
- * serializing and deserializing must be equal and have the same hashCode. It isn't required that such a copy be entirely unchanged.
- */
-public interface Writeable {
-
-    /**
-     * Write this into the {@linkplain StreamOutput}.
-     */
-    void writeTo(StreamOutput out) throws IOException;
-
-    /**
-     * Reference to a method that can write some object to a {@link StreamOutput}.
-     * <p>
-     * By convention this is a method from {@link StreamOutput} itself (e.g., {@link StreamOutput#writeString}). If the value can be
-     * {@code null}, then the "optional" variant of methods should be used!
-     * <p>
-     * Most classes should implement {@link Writeable} and the {@link Writeable#writeTo(StreamOutput)} method should <em>use</em>
-     * {@link StreamOutput} methods directly or this indirectly:
-     * <pre><code>
-     * public void writeTo(StreamOutput out) throws IOException {
-     *     out.writeVInt(someValue);
-     *     out.writeMapOfLists(someMap, StreamOutput::writeString, StreamOutput::writeString);
-     * }
-     * </code></pre>
-     */
-    @FunctionalInterface
-    interface Writer<V> {
-
-        /**
-         * Write {@code V}-type {@code value} to the {@code out}put stream.
-         *
-         * @param out Output to write the {@code value} too
-         * @param value The value to add
-         */
-        void write(StreamOutput out, V value) throws IOException;
-
-    }
-
-    /**
-     * Reference to a method that can read some object from a stream. By convention this is a constructor that takes
-     * {@linkplain StreamInput} as an argument for most classes and a static method for things like enums. Returning null from one of these
-     * is always wrong - for that we use methods like {@link StreamInput#readOptionalWriteable(Reader)}.
-     * <p>
-     * As most classes will implement this via a constructor (or a static method in the case of enumerations), it's something that should
-     * look like:
-     * <pre><code>
-     * public MyClass(final StreamInput in) throws IOException {
-     *     this.someValue = in.readVInt();
-     *     this.someMap = in.readMapOfLists(StreamInput::readString, StreamInput::readString);
-     * }
-     * </code></pre>
-     */
-    @FunctionalInterface
-    interface Reader<V> {
-
-        /**
-         * Read {@code V}-type value from a stream.
-         *
-         * @param in Input to read the value from
-         */
-        V read(StreamInput in) throws IOException;
-
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/common/joda/Joda.java b/server/src/main/java/org/opensearch/common/joda/Joda.java
index f644ef43ae472..79a9b1a09b801 100644
--- a/server/src/main/java/org/opensearch/common/joda/Joda.java
+++ b/server/src/main/java/org/opensearch/common/joda/Joda.java
@@ -34,11 +34,13 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.FormatNames;
 import org.opensearch.common.util.LazyInitializable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.joda.time.Chronology;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeField;
@@ -65,6 +67,13 @@
 import java.util.Locale;
 import java.util.regex.Pattern;
 
+/**
+ * Joda class.
+ *
+ * @deprecated
+ *
+ * @opensearch.internal
+ */
 @Deprecated
 public class Joda {
     // Joda.forPattern could be used even before the logging is initialized.
@@ -310,6 +319,36 @@ public static JodaDateFormatter forPattern(String input) {
         return new JodaDateFormatter(input, formatter, formatter);
     }
 
+    public static void writeTimeZone(final StreamOutput out, final DateTimeZone timeZone) throws IOException {
+        out.writeString(timeZone.getID());
+    }
+
+    public static void writeOptionalTimeZone(final StreamOutput out, final DateTimeZone timeZone) throws IOException {
+        if (timeZone == null) {
+            out.writeBoolean(false);
+        } else {
+            out.writeBoolean(true);
+            writeTimeZone(out, timeZone);
+        }
+    }
+
+    /**
+     * Read a {@linkplain DateTimeZone} from a {@linkplain StreamInput}.
+     */
+    public static DateTimeZone readTimeZone(final StreamInput in) throws IOException {
+        return DateTimeZone.forID(in.readString());
+    }
+
+    /**
+     * Read an optional {@linkplain DateTimeZone}.
+     */
+    public static DateTimeZone readOptionalTimeZone(final StreamInput in) throws IOException {
+        if (in.readBoolean()) {
+            return DateTimeZone.forID(in.readString());
+        }
+        return null;
+    }
+
     private static void maybeLogJodaDeprecation(String format) {
         if (JodaDeprecationPatterns.isDeprecatedPattern(format)) {
             String suggestion = JodaDeprecationPatterns.formatSuggestion(format);
@@ -392,6 +431,11 @@ public static boolean isJodaPattern(Version version, String pattern) {
         return version.before(LegacyESVersion.V_7_0_0) && pattern.startsWith("8") == false;
     }
 
+    /**
+     * parses epcoch timers
+     *
+     * @opensearch.internal
+     */
     public static class EpochTimeParser implements DateTimeParser {
 
         private static final Pattern scientificNotation = Pattern.compile("[Ee]");
@@ -458,6 +502,11 @@ private static DeprecationLogger getDeprecationLogger() {
         return deprecationLogger.getOrCompute();
     }
 
+    /**
+     * Epoch timer printer
+     *
+     * @opensearch.internal
+     */
     public static class EpochTimePrinter implements DateTimePrinter {
 
         private boolean hasMilliSecondPrecision;
diff --git a/server/src/main/java/org/opensearch/common/joda/JodaDateFormatter.java b/server/src/main/java/org/opensearch/common/joda/JodaDateFormatter.java
index 3b36e36624fe3..12d48a0b362ce 100644
--- a/server/src/main/java/org/opensearch/common/joda/JodaDateFormatter.java
+++ b/server/src/main/java/org/opensearch/common/joda/JodaDateFormatter.java
@@ -46,6 +46,11 @@
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * Joda date formatter.
+ *
+ * @opensearch.internal
+ */
 public class JodaDateFormatter implements DateFormatter {
 
     final String pattern;
diff --git a/server/src/main/java/org/opensearch/common/joda/JodaDateMathParser.java b/server/src/main/java/org/opensearch/common/joda/JodaDateMathParser.java
index 7ea576f9852c5..0de6dec1c25bd 100644
--- a/server/src/main/java/org/opensearch/common/joda/JodaDateMathParser.java
+++ b/server/src/main/java/org/opensearch/common/joda/JodaDateMathParser.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common.joda;
 
-import org.joda.time.DateTimeZone;
-import org.joda.time.MutableDateTime;
-import org.joda.time.format.DateTimeFormatter;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.time.DateUtils;
+import org.joda.time.DateTimeZone;
+import org.joda.time.MutableDateTime;
+import org.joda.time.format.DateTimeFormatter;
 
 import java.time.Instant;
 import java.time.ZoneId;
@@ -50,6 +50,8 @@
  * The format of the datetime is configurable, and unix timestamps can also be used. Datemath
  * is appended to a datetime with the following syntax:
  * <code>||[+-/](\d+)?[yMwdhHms]</code>.
+ *
+ * @opensearch.internal
  */
 public class JodaDateMathParser implements DateMathParser {
 
diff --git a/server/src/main/java/org/opensearch/common/joda/JodaDeprecationPatterns.java b/server/src/main/java/org/opensearch/common/joda/JodaDeprecationPatterns.java
index cf0e2394c7805..efb6362ab63aa 100644
--- a/server/src/main/java/org/opensearch/common/joda/JodaDeprecationPatterns.java
+++ b/server/src/main/java/org/opensearch/common/joda/JodaDeprecationPatterns.java
@@ -42,6 +42,11 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * Deprecated patters for joda date/time
+ *
+ * @opensearch.internal
+ */
 public class JodaDeprecationPatterns {
     public static final String USE_NEW_FORMAT_SPECIFIERS = "Use new java.time date format specifiers.";
     private static Map<String, String> JODA_PATTERNS_DEPRECATIONS = new LinkedHashMap<>();
diff --git a/server/src/main/java/org/opensearch/common/joda/package-info.java b/server/src/main/java/org/opensearch/common/joda/package-info.java
new file mode 100644
index 0000000000000..55ed8d9592a6d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/joda/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Joda Time package. */
+package org.opensearch.common.joda;
diff --git a/server/src/main/java/org/opensearch/common/logging/DeprecatedMessage.java b/server/src/main/java/org/opensearch/common/logging/DeprecatedMessage.java
index bb8ded8098b88..25c1ba9675600 100644
--- a/server/src/main/java/org/opensearch/common/logging/DeprecatedMessage.java
+++ b/server/src/main/java/org/opensearch/common/logging/DeprecatedMessage.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.common.logging;
 
-import java.util.Map;
-
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.core.common.Strings;
 
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * A logger message used by {@link DeprecationLogger}.
  * Carries x-opaque-id field if provided in the headers. Will populate the x-opaque-id field in JSON logs.
+ *
+ * @opensearch.internal
  */
 public class DeprecatedMessage extends OpenSearchLogMessage {
     public static final String X_OPAQUE_ID_FIELD_NAME = "x-opaque-id";
diff --git a/server/src/main/java/org/opensearch/common/logging/DeprecationLogger.java b/server/src/main/java/org/opensearch/common/logging/DeprecationLogger.java
index 9e9715b8fa867..98b4ebbc330da 100644
--- a/server/src/main/java/org/opensearch/common/logging/DeprecationLogger.java
+++ b/server/src/main/java/org/opensearch/common/logging/DeprecationLogger.java
@@ -49,6 +49,8 @@
  * uses {@link RateLimitingFilter} to prevent the same message being logged repeatedly in a short span of time. This
  * key is combined with the <code>X-Opaque-Id</code> request header value, if supplied, which allows for per-client
  * message limiting.
+ *
+ * @opensearch.internal
  */
 public class DeprecationLogger {
 
@@ -103,6 +105,11 @@ public DeprecationLoggerBuilder deprecate(final String key, final String msg, fi
         return new DeprecationLoggerBuilder().withDeprecation(key, msg, params);
     }
 
+    /**
+     * The builder for the deprecation logger
+     *
+     * @opensearch.internal
+     */
     public class DeprecationLoggerBuilder {
 
         public DeprecationLoggerBuilder withDeprecation(String key, String msg, Object[] params) {
diff --git a/server/src/main/java/org/opensearch/common/logging/HeaderWarning.java b/server/src/main/java/org/opensearch/common/logging/HeaderWarning.java
index 1914b86703640..103033ccac312 100644
--- a/server/src/main/java/org/opensearch/common/logging/HeaderWarning.java
+++ b/server/src/main/java/org/opensearch/common/logging/HeaderWarning.java
@@ -35,6 +35,7 @@
 import org.opensearch.Build;
 import org.opensearch.Version;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.logging.LoggerMessageFormat;
 import org.opensearch.tasks.Task;
 
 import java.nio.charset.Charset;
@@ -52,6 +53,8 @@
  * This is a simplistic logger that adds warning messages to HTTP headers.
  * Use <code>HeaderWarning.addWarning(message,params)</code>. Message will be formatted according to RFC7234.
  * The result will be returned as HTTP response headers.
+ *
+ * @opensearch.internal
  */
 public class HeaderWarning {
     /**
diff --git a/server/src/main/java/org/opensearch/common/logging/HeaderWarningAppender.java b/server/src/main/java/org/opensearch/common/logging/HeaderWarningAppender.java
index 6643c03b09e54..16c3858b15761 100644
--- a/server/src/main/java/org/opensearch/common/logging/HeaderWarningAppender.java
+++ b/server/src/main/java/org/opensearch/common/logging/HeaderWarningAppender.java
@@ -43,6 +43,11 @@
 import org.apache.logging.log4j.core.config.plugins.PluginFactory;
 import org.apache.logging.log4j.message.Message;
 
+/**
+ * Appends warnings to the header
+ *
+ * @opensearch.internal
+ */
 @Plugin(name = "HeaderWarningAppender", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE)
 public class HeaderWarningAppender extends AbstractAppender {
     public HeaderWarningAppender(String name, Filter filter) {
diff --git a/server/src/main/java/org/opensearch/common/logging/JsonThrowablePatternConverter.java b/server/src/main/java/org/opensearch/common/logging/JsonThrowablePatternConverter.java
index ff70ba883e15a..e259d5d9e3e33 100644
--- a/server/src/main/java/org/opensearch/common/logging/JsonThrowablePatternConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/JsonThrowablePatternConverter.java
@@ -30,6 +30,7 @@
 package org.opensearch.common.logging;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
@@ -49,6 +50,8 @@
  *
  * Reusing @link org.apache.logging.log4j.core.pattern.ExtendedThrowablePatternConverter which already converts a Throwable from
  * LoggingEvent into a multiline string
+ *
+ * @opensearch.internal
  */
 @Plugin(name = "JsonThrowablePatternConverter", category = PatternConverter.CATEGORY)
 @ConverterKeys({ "exceptionAsJson" })
diff --git a/server/src/main/java/org/opensearch/common/logging/LogConfigurator.java b/server/src/main/java/org/opensearch/common/logging/LogConfigurator.java
index f75be70851a4b..3d7f95fc4b34a 100644
--- a/server/src/main/java/org/opensearch/common/logging/LogConfigurator.java
+++ b/server/src/main/java/org/opensearch/common/logging/LogConfigurator.java
@@ -43,7 +43,6 @@
 import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
 import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;
 import org.apache.logging.log4j.core.config.composite.CompositeConfiguration;
-import org.apache.logging.log4j.core.config.plugins.util.PluginManager;
 import org.apache.logging.log4j.core.config.properties.PropertiesConfiguration;
 import org.apache.logging.log4j.core.config.properties.PropertiesConfigurationBuilder;
 import org.apache.logging.log4j.core.config.properties.PropertiesConfigurationFactory;
@@ -80,6 +79,11 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.StreamSupport;
 
+/**
+ * Configures the logger
+ *
+ * @opensearch.internal
+ */
 public class LogConfigurator {
 
     /*
@@ -142,13 +146,6 @@ public static void configure(final Environment environment) throws IOException,
         configure(environment.settings(), environment.configFile(), environment.logsFile());
     }
 
-    /**
-     * Load logging plugins so we can have {@code node_name} in the pattern.
-     */
-    public static void loadLog4jPlugins() {
-        PluginManager.addPackage(LogConfigurator.class.getPackage().getName());
-    }
-
     /**
      * Sets the node name. This is called before logging is configured if the
      * node name is set in opensearch.yml. Otherwise it is called as soon
@@ -174,8 +171,6 @@ private static void configure(final Settings settings, final Path configsPath, f
         Objects.requireNonNull(configsPath);
         Objects.requireNonNull(logsPath);
 
-        loadLog4jPlugins();
-
         setLogConfigurationSystemProperty(logsPath, settings);
         // we initialize the status logger immediately otherwise Log4j will complain when we try to get the context
         configureStatusLogger();
@@ -253,7 +248,7 @@ public FileVisitResult visitFile(final Path file, final BasicFileAttributes attr
                 .warn(
                     "Some logging configurations have %marker but don't have %node_name. "
                         + "We will automatically add %node_name to the pattern to ease the migration for users who customize "
-                        + "log4j2.properties but will stop this behavior in 7.0. You should manually replace `%node_name` with "
+                        + "log4j2.properties but will stop this behavior in 3.0. You should manually replace `%node_name` with "
                         + "`[%node_name]%marker ` in these locations:\n  {}",
                     deprecatedLocationsString
                 );
@@ -314,6 +309,7 @@ private static void configureLoggerLevels(final Settings settings) {
      */
     @SuppressForbidden(reason = "sets system property for logging configuration")
     private static void setLogConfigurationSystemProperty(final Path logsPath, final Settings settings) {
+        System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
         System.setProperty("opensearch.logs.base_path", logsPath.toString());
         System.setProperty("opensearch.logs.cluster_name", ClusterName.CLUSTER_NAME_SETTING.get(settings).value());
         System.setProperty("opensearch.logs.node_name", Node.NODE_NAME_SETTING.get(settings));
diff --git a/server/src/main/java/org/opensearch/common/logging/Loggers.java b/server/src/main/java/org/opensearch/common/logging/Loggers.java
index 845f6f2ad1995..9a88afef90867 100644
--- a/server/src/main/java/org/opensearch/common/logging/Loggers.java
+++ b/server/src/main/java/org/opensearch/common/logging/Loggers.java
@@ -41,15 +41,17 @@
 import org.apache.logging.log4j.core.config.Configurator;
 import org.apache.logging.log4j.core.config.LoggerConfig;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Map;
 
-import static org.opensearch.common.util.CollectionUtils.asArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.asArrayList;
 
 /**
  * A set of utilities around Logging.
+ *
+ * @opensearch.internal
  */
 public class Loggers {
 
diff --git a/server/src/main/java/org/opensearch/common/logging/LoggingOutputStream.java b/server/src/main/java/org/opensearch/common/logging/LoggingOutputStream.java
index 64905ced94632..c1529b1875a59 100644
--- a/server/src/main/java/org/opensearch/common/logging/LoggingOutputStream.java
+++ b/server/src/main/java/org/opensearch/common/logging/LoggingOutputStream.java
@@ -42,6 +42,8 @@
 
 /**
  * A stream whose output is sent to the configured logger, line by line.
+ *
+ * @opensearch.internal
  */
 class LoggingOutputStream extends OutputStream {
     /** The starting length of the buffer */
diff --git a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
index e882ccc5f59f9..7bbb83e311adc 100644
--- a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
@@ -37,13 +37,15 @@
 import org.apache.logging.log4j.core.pattern.ConverterKeys;
 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
 import org.apache.logging.log4j.core.pattern.PatternConverter;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 
 import java.util.Locale;
 
 /**
  * Pattern converter to format the node_and_cluster_id variable into JSON fields <code>node.id</code> and <code>cluster.uuid</code>.
  * Keeping those two fields together assures that they will be atomically set and become visible in logs at the same time.
+ *
+ * @opensearch.internal
  */
 @Plugin(category = PatternConverter.CATEGORY, name = "NodeAndClusterIdConverter")
 @ConverterKeys({ "node_and_cluster_id" })
diff --git a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdStateListener.java b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdStateListener.java
index 48eba12ae0e1f..18051f9ca50c4 100644
--- a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdStateListener.java
+++ b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdStateListener.java
@@ -44,6 +44,8 @@
  * The {@link NodeAndClusterIdStateListener} listens to cluster state changes and ONLY when receives the first update
  * it sets the clusterUUID and nodeID in log4j pattern converter {@link NodeAndClusterIdConverter}.
  * Once the first update is received, it will automatically be de-registered from subsequent updates.
+ *
+ * @opensearch.internal
  */
 public class NodeAndClusterIdStateListener implements ClusterStateObserver.Listener {
     private static final Logger logger = LogManager.getLogger(NodeAndClusterIdStateListener.class);
diff --git a/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java b/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
index a21857d082ecf..8e61492c57388 100644
--- a/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
@@ -32,20 +32,22 @@
 
 package org.opensearch.common.logging;
 
-import java.util.Arrays;
-
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.pattern.ConverterKeys;
 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
 import org.apache.logging.log4j.core.pattern.PatternConverter;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
+
+import java.util.Arrays;
 
 /**
  * Converts {@code %node_name} in log4j patterns into the current node name.
  * We can't use a system property for this because the node name system
  * property is only set if the node name is explicitly defined in
  * opensearch.yml.
+ *
+ * @opensearch.internal
  */
 @Plugin(category = PatternConverter.CATEGORY, name = "NodeNamePatternConverter")
 @ConverterKeys({ "node_name" })
diff --git a/server/src/main/java/org/opensearch/common/logging/OpenSearchJsonLayout.java b/server/src/main/java/org/opensearch/common/logging/OpenSearchJsonLayout.java
index 3cb4b591e2cd3..60df94036cc6b 100644
--- a/server/src/main/java/org/opensearch/common/logging/OpenSearchJsonLayout.java
+++ b/server/src/main/java/org/opensearch/common/logging/OpenSearchJsonLayout.java
@@ -34,15 +34,17 @@
 
 import org.apache.logging.log4j.core.Layout;
 import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.Node;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
 import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
+import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
 import org.apache.logging.log4j.core.config.plugins.PluginFactory;
 import org.apache.logging.log4j.core.layout.AbstractStringLayout;
 import org.apache.logging.log4j.core.layout.ByteBufferDestination;
 import org.apache.logging.log4j.core.layout.PatternLayout;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
@@ -83,24 +85,44 @@
  * <p>
  * The value taken from %OpenSearchMessageField{message} has to be a simple escaped JSON value and is populated in subclasses of
  * <code>OpenSearchLogMessage</code>
+ * <p>
+ * The <code>message</code> field is truncated at 10000 characters by default. This limit can be controlled by setting the
+ * <code>appender.logger.layout.maxmessagelength</code> to the desired limit or to <code>0</code> to disable truncation.
+ *
+ * @opensearch.internal
  */
 @Plugin(name = "OpenSearchJsonLayout", category = Node.CATEGORY, elementType = Layout.ELEMENT_TYPE, printObject = true)
 public class OpenSearchJsonLayout extends AbstractStringLayout {
 
     private final PatternLayout patternLayout;
 
-    protected OpenSearchJsonLayout(String typeName, Charset charset, String[] opensearchMessageFields) {
+    protected OpenSearchJsonLayout(
+        String typeName,
+        Charset charset,
+        String[] opensearchMessageFields,
+        int maxMessageLength,
+        Configuration configuration
+    ) {
         super(charset);
         this.patternLayout = PatternLayout.newBuilder()
-            .withPattern(pattern(typeName, opensearchMessageFields))
+            .withPattern(pattern(typeName, opensearchMessageFields, maxMessageLength))
             .withAlwaysWriteExceptions(false)
+            .withConfiguration(configuration)
             .build();
     }
 
-    private String pattern(String type, String[] opensearchMessageFields) {
+    private String pattern(String type, String[] opensearchMessageFields, int maxMessageLength) {
         if (Strings.isEmpty(type)) {
             throw new IllegalArgumentException("layout parameter 'type_name' cannot be empty");
         }
+
+        String messageFormat = "%m";
+        if (maxMessageLength < 0) {
+            throw new IllegalArgumentException("layout parameter 'maxmessagelength' cannot be a negative number");
+        } else if (maxMessageLength > 0) {
+            messageFormat = "%.-" + Integer.toString(maxMessageLength) + "m";
+        }
+
         Map<String, Object> map = new LinkedHashMap<>();
         map.put("type", inQuotes(type));
         map.put("timestamp", inQuotes("%d{yyyy-MM-dd'T'HH:mm:ss,SSSZZ}"));
@@ -108,7 +130,7 @@ private String pattern(String type, String[] opensearchMessageFields) {
         map.put("component", inQuotes("%c{1.}"));
         map.put("cluster.name", inQuotes("${sys:opensearch.logs.cluster_name}"));
         map.put("node.name", inQuotes("%node_name"));
-        map.put("message", inQuotes("%notEmpty{%enc{%marker}{JSON} }%enc{%.-10000m}{JSON}"));
+        map.put("message", inQuotes("%notEmpty{%enc{%marker}{JSON} }%enc{" + messageFormat + "}{JSON}"));
 
         for (String key : opensearchMessageFields) {
             map.put(key, inQuotes("%OpenSearchMessageField{" + key + "}"));
@@ -160,14 +182,25 @@ private String inQuotes(String s) {
     }
 
     @PluginFactory
-    public static OpenSearchJsonLayout createLayout(String type, Charset charset, String[] opensearchmessagefields) {
-        return new OpenSearchJsonLayout(type, charset, opensearchmessagefields);
+    public static OpenSearchJsonLayout createLayout(
+        String type,
+        Charset charset,
+        String[] opensearchmessagefields,
+        int maxMessageLength,
+        Configuration configuration
+    ) {
+        return new OpenSearchJsonLayout(type, charset, opensearchmessagefields, maxMessageLength, configuration);
     }
 
     PatternLayout getPatternLayout() {
         return patternLayout;
     }
 
+    /**
+     * Builder for a json layout
+     *
+     * @opensearch.internal
+     */
     public static class Builder<B extends OpenSearchJsonLayout.Builder<B>> extends AbstractStringLayout.Builder<B>
         implements
             org.apache.logging.log4j.core.util.Builder<OpenSearchJsonLayout> {
@@ -181,14 +214,21 @@ public static class Builder<B extends OpenSearchJsonLayout.Builder<B>> extends A
         @PluginAttribute("opensearchmessagefields")
         private String opensearchMessageFields;
 
+        @PluginAttribute(value = "maxmessagelength", defaultInt = 10000)
+        private int maxMessageLength;
+
+        @PluginConfiguration
+        private Configuration configuration;
+
         public Builder() {
             setCharset(StandardCharsets.UTF_8);
+            setMaxMessageLength(10000);
         }
 
         @Override
         public OpenSearchJsonLayout build() {
             String[] split = Strings.isNullOrEmpty(opensearchMessageFields) ? new String[] {} : opensearchMessageFields.split(",");
-            return OpenSearchJsonLayout.createLayout(type, charset, split);
+            return OpenSearchJsonLayout.createLayout(type, charset, split, maxMessageLength, configuration);
         }
 
         public Charset getCharset() {
@@ -217,6 +257,24 @@ public B setOpenSearchMessageFields(String opensearchMessageFields) {
             this.opensearchMessageFields = opensearchMessageFields;
             return asBuilder();
         }
+
+        public int getMaxMessageLength() {
+            return maxMessageLength;
+        }
+
+        public B setMaxMessageLength(final int maxMessageLength) {
+            this.maxMessageLength = maxMessageLength;
+            return asBuilder();
+        }
+
+        public Configuration getConfiguration() {
+            return configuration;
+        }
+
+        public B setConfiguration(final Configuration configuration) {
+            this.configuration = configuration;
+            return asBuilder();
+        }
     }
 
     @PluginBuilderFactory
diff --git a/server/src/main/java/org/opensearch/common/logging/OpenSearchLogMessage.java b/server/src/main/java/org/opensearch/common/logging/OpenSearchLogMessage.java
index dafe315ba046c..f163e5e6a2539 100644
--- a/server/src/main/java/org/opensearch/common/logging/OpenSearchLogMessage.java
+++ b/server/src/main/java/org/opensearch/common/logging/OpenSearchLogMessage.java
@@ -41,6 +41,8 @@
 
 /**
  * A base class for custom log4j logger messages. Carries additional fields which will populate JSON fields in logs.
+ *
+ * @opensearch.internal
  */
 @SuppressLoggerChecks(reason = "Safe as this is abstract class")
 public abstract class OpenSearchLogMessage extends ParameterizedMessage {
diff --git a/server/src/main/java/org/opensearch/common/logging/OpenSearchMessageFieldConverter.java b/server/src/main/java/org/opensearch/common/logging/OpenSearchMessageFieldConverter.java
index 6e0c1c4ef4c1b..596f8716c1103 100644
--- a/server/src/main/java/org/opensearch/common/logging/OpenSearchMessageFieldConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/OpenSearchMessageFieldConverter.java
@@ -39,11 +39,13 @@
 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
 import org.apache.logging.log4j.core.pattern.PatternConverter;
 import org.apache.logging.log4j.util.StringBuilders;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 /**
  * Pattern converter to populate OpenSearchMessageField in a pattern.
  * It will only populate these if the event have message of type <code>OpenSearchLogMessage</code>.
+ *
+ * @opensearch.internal
  */
 @Plugin(category = PatternConverter.CATEGORY, name = "OpenSearchMessageField")
 @ConverterKeys({ "OpenSearchMessageField" })
diff --git a/server/src/main/java/org/opensearch/common/logging/PrefixLogger.java b/server/src/main/java/org/opensearch/common/logging/PrefixLogger.java
index eaec8a71e741f..7d55ee7dbf975 100644
--- a/server/src/main/java/org/opensearch/common/logging/PrefixLogger.java
+++ b/server/src/main/java/org/opensearch/common/logging/PrefixLogger.java
@@ -45,6 +45,8 @@
 /**
  * A logger that prefixes all messages with a fixed prefix specified during construction. The prefix mechanism uses the marker construct, so
  * for the prefixes to appear, the logging layout pattern must include the marker in its pattern.
+ *
+ * @opensearch.internal
  */
 class PrefixLogger extends ExtendedLoggerWrapper {
 
diff --git a/server/src/main/java/org/opensearch/common/logging/RateLimitingFilter.java b/server/src/main/java/org/opensearch/common/logging/RateLimitingFilter.java
index a93f1188a76a2..c6e8a714f045d 100644
--- a/server/src/main/java/org/opensearch/common/logging/RateLimitingFilter.java
+++ b/server/src/main/java/org/opensearch/common/logging/RateLimitingFilter.java
@@ -51,6 +51,11 @@
 
 import static org.opensearch.common.logging.DeprecatedMessage.X_OPAQUE_ID_FIELD_NAME;
 
+/**
+ * Filter that is rate limiting
+ *
+ * @opensearch.internal
+ */
 @Plugin(name = "RateLimitingFilter", category = Node.CATEGORY, elementType = Filter.ELEMENT_TYPE)
 public class RateLimitingFilter extends AbstractFilter {
 
diff --git a/server/src/main/java/org/opensearch/common/logging/package-info.java b/server/src/main/java/org/opensearch/common/logging/package-info.java
new file mode 100644
index 0000000000000..8440be23c5fee
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/logging/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base logger package. */
+package org.opensearch.common.logging;
diff --git a/server/src/main/java/org/opensearch/common/lucene/BytesRefs.java b/server/src/main/java/org/opensearch/common/lucene/BytesRefs.java
index 34e32b03426d4..2600a9a96c9ec 100644
--- a/server/src/main/java/org/opensearch/common/lucene/BytesRefs.java
+++ b/server/src/main/java/org/opensearch/common/lucene/BytesRefs.java
@@ -35,6 +35,11 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 
+/**
+ * Base bytes ref.
+ *
+ * @opensearch.internal
+ */
 public class BytesRefs {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/lucene/LoggerInfoStream.java b/server/src/main/java/org/opensearch/common/lucene/LoggerInfoStream.java
index deca9baf56f1d..45a07e397cd6a 100644
--- a/server/src/main/java/org/opensearch/common/lucene/LoggerInfoStream.java
+++ b/server/src/main/java/org/opensearch/common/lucene/LoggerInfoStream.java
@@ -39,8 +39,12 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
-/** An InfoStream (for Lucene's IndexWriter) that redirects
- *  messages to "lucene.iw.ifd" and "lucene.iw" Logger.trace. */
+/**
+ * An InfoStream (for Lucene's IndexWriter) that redirects
+ *  messages to "lucene.iw.ifd" and "lucene.iw" Logger.trace.
+ *
+ * @opensearch.internal
+ */
 public final class LoggerInfoStream extends InfoStream {
 
     private final Logger parentLogger;
diff --git a/server/src/main/java/org/opensearch/common/lucene/Lucene.java b/server/src/main/java/org/opensearch/common/lucene/Lucene.java
index 4cbc7a6668dee..c61b1bcc676a6 100644
--- a/server/src/main/java/org/opensearch/common/lucene/Lucene.java
+++ b/server/src/main/java/org/opensearch/common/lucene/Lucene.java
@@ -41,6 +41,7 @@
 import org.apache.lucene.document.LatLonDocValuesField;
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.index.BinaryDocValues;
+import org.apache.lucene.index.ByteVectorValues;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FieldInfo;
@@ -49,6 +50,7 @@
 import org.apache.lucene.index.FilterCodecReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.FilterLeafReader;
+import org.apache.lucene.index.FloatVectorValues;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.IndexFormatTooNewException;
@@ -68,8 +70,9 @@
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.index.StoredFieldVisitor;
+import org.apache.lucene.index.StoredFields;
+import org.apache.lucene.index.TermVectors;
 import org.apache.lucene.index.Terms;
-import org.apache.lucene.index.VectorValues;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.FieldDoc;
@@ -99,15 +102,16 @@
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.iterable.Iterables;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.search.sort.SortedWiderNumericSortField;
 
 import java.io.IOException;
 import java.math.BigInteger;
@@ -119,8 +123,13 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Main lucene class.
+ *
+ * @opensearch.internal
+ */
 public class Lucene {
-    public static final String LATEST_CODEC = "Lucene91";
+    public static final String LATEST_CODEC = "Lucene95";
 
     public static final String SOFT_DELETES_FIELD = "__soft_deletes";
 
@@ -157,6 +166,16 @@ public static SegmentInfos readSegmentInfos(Directory directory) throws IOExcept
         return SegmentInfos.readLatestCommit(directory);
     }
 
+    /**
+     * A variant of {@link #readSegmentInfos(Directory)} that supports reading indices written by
+     * older major versions of Lucene. This leverages Lucene's "expert" readLatestCommit API. The
+     * {@link org.opensearch.Version} parameter determines the minimum supported Lucene major version.
+     */
+    public static SegmentInfos readSegmentInfos(Directory directory, org.opensearch.Version minimumVersion) throws IOException {
+        final int minSupportedLuceneMajor = minimumVersion.minimumIndexCompatibilityVersion().luceneVersion.major;
+        return SegmentInfos.readLatestCommit(directory, minSupportedLuceneMajor);
+    }
+
     /**
      * Returns an iterable that allows to iterate over all files in this segments info
      */
@@ -609,8 +628,8 @@ public static void writeSortField(StreamOutput out, SortField sortField) throws
             SortField newSortField = new SortField(sortField.getField(), SortField.Type.STRING, sortField.getReverse());
             newSortField.setMissingValue(sortField.getMissingValue());
             sortField = newSortField;
-        } else if (sortField.getClass() == SortedNumericSortField.class) {
-            // for multi-valued sort field, we replace the SortedSetSortField with a simple SortField.
+        } else if (sortField.getClass() == SortedNumericSortField.class || sortField.getClass() == SortedWiderNumericSortField.class) {
+            // for multi-valued sort field, we replace the SortedNumericSortField/SortedWiderNumericSortField with a simple SortField.
             // It works because the sort field is only used to merge results from different shards.
             SortField newSortField = new SortField(
                 sortField.getField(),
@@ -1088,6 +1107,11 @@ public Fields getTermVectors(int docID) {
                 return null;
             }
 
+            @Override
+            public TermVectors termVectors() throws IOException {
+                return null;
+            }
+
             public int numDocs() {
                 return 0;
             }
@@ -1098,6 +1122,11 @@ public int maxDoc() {
 
             public void document(int docID, StoredFieldVisitor visitor) {}
 
+            @Override
+            public StoredFields storedFields() throws IOException {
+                return null;
+            }
+
             protected void doClose() {}
 
             public LeafMetaData getMetaData() {
@@ -1113,7 +1142,17 @@ public CacheHelper getReaderCacheHelper() {
             }
 
             @Override
-            public VectorValues getVectorValues(String field) throws IOException {
+            public FloatVectorValues getFloatVectorValues(String field) throws IOException {
+                return null;
+            }
+
+            @Override
+            public ByteVectorValues getByteVectorValues(String field) throws IOException {
+                return null;
+            }
+
+            @Override
+            public TopDocs searchNearestVectors(String field, byte[] target, int k, Bits acceptDocs, int visitedLimit) throws IOException {
                 return null;
             }
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/MinimumScoreCollector.java b/server/src/main/java/org/opensearch/common/lucene/MinimumScoreCollector.java
index 81c98c862d2b2..32581f2c843d5 100644
--- a/server/src/main/java/org/opensearch/common/lucene/MinimumScoreCollector.java
+++ b/server/src/main/java/org/opensearch/common/lucene/MinimumScoreCollector.java
@@ -42,6 +42,11 @@
 
 import java.io.IOException;
 
+/**
+ * A minimum score collector.
+ *
+ * @opensearch.internal
+ */
 public class MinimumScoreCollector extends SimpleCollector {
 
     private final Collector collector;
@@ -55,6 +60,10 @@ public MinimumScoreCollector(Collector collector, float minimumScore) {
         this.minimumScore = minimumScore;
     }
 
+    public Collector getCollector() {
+        return collector;
+    }
+
     @Override
     public void setScorer(Scorable scorer) throws IOException {
         if (!(scorer instanceof ScoreCachingWrappingScorer)) {
diff --git a/server/src/main/java/org/opensearch/common/lucene/ScorerAware.java b/server/src/main/java/org/opensearch/common/lucene/ScorerAware.java
index 4fe253878021c..f8a0758a9533e 100644
--- a/server/src/main/java/org/opensearch/common/lucene/ScorerAware.java
+++ b/server/src/main/java/org/opensearch/common/lucene/ScorerAware.java
@@ -33,6 +33,11 @@
 
 import org.apache.lucene.search.Scorable;
 
+/**
+ * Interface that is scorer aware.
+ *
+ * @opensearch.internal
+ */
 public interface ScorerAware {
 
     void setScorer(Scorable scorer);
diff --git a/server/src/main/java/org/opensearch/common/lucene/ShardCoreKeyMap.java b/server/src/main/java/org/opensearch/common/lucene/ShardCoreKeyMap.java
index 22360a23586df..0ffd633e5a967 100644
--- a/server/src/main/java/org/opensearch/common/lucene/ShardCoreKeyMap.java
+++ b/server/src/main/java/org/opensearch/common/lucene/ShardCoreKeyMap.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
-import org.opensearch.Assertions;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.ShardUtils;
 
 import java.io.IOException;
@@ -57,6 +57,8 @@
  * segments so that at any time it only tracks live segments.
  *
  * NOTE: This is heavy. Avoid using this class unless absolutely required.
+ *
+ * @opensearch.internal
  */
 public final class ShardCoreKeyMap {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/FilterableTermsEnum.java b/server/src/main/java/org/opensearch/common/lucene/index/FilterableTermsEnum.java
index ebd108b79d61a..61c9e9f54cb51 100644
--- a/server/src/main/java/org/opensearch/common/lucene/index/FilterableTermsEnum.java
+++ b/server/src/main/java/org/opensearch/common/lucene/index/FilterableTermsEnum.java
@@ -60,9 +60,16 @@
  * A frequency TermsEnum that returns frequencies derived from a collection of
  * cached leaf termEnums. It also allows to provide a filter to explicitly
  * compute frequencies only for docs that match the filter (heavier!).
+ *
+ * @opensearch.internal
  */
 public class FilterableTermsEnum extends TermsEnum {
 
+    /**
+     * Holds a terms enum, doc enum, and bitset
+     *
+     * @opensearch.internal
+     */
     static class Holder {
         final TermsEnum termsEnum;
         @Nullable
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/FreqTermsEnum.java b/server/src/main/java/org/opensearch/common/lucene/index/FreqTermsEnum.java
index bedd372d28453..eabdc25f1125a 100644
--- a/server/src/main/java/org/opensearch/common/lucene/index/FreqTermsEnum.java
+++ b/server/src/main/java/org/opensearch/common/lucene/index/FreqTermsEnum.java
@@ -48,6 +48,8 @@
 
 /**
  * A frequency terms enum that maintains a cache of docFreq, totalTermFreq, or both for repeated term lookup.
+ *
+ * @opensearch.internal
  */
 public class FreqTermsEnum extends FilterableTermsEnum implements Releasable {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReader.java b/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReader.java
index 8d99eda7acf7d..77609822d3d90 100644
--- a/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReader.java
+++ b/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReader.java
@@ -36,13 +36,15 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * A {@link org.apache.lucene.index.FilterDirectoryReader} that exposes
  * OpenSearch internal per shard / index information like the shard ID.
+ *
+ * @opensearch.internal
  */
 public final class OpenSearchDirectoryReader extends FilterDirectoryReader {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchLeafReader.java b/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchLeafReader.java
index 5ff20666ed68d..597b43cc3277f 100644
--- a/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchLeafReader.java
+++ b/server/src/main/java/org/opensearch/common/lucene/index/OpenSearchLeafReader.java
@@ -34,11 +34,13 @@
 import org.apache.lucene.codecs.StoredFieldsReader;
 import org.apache.lucene.index.FilterLeafReader;
 import org.apache.lucene.index.LeafReader;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 /**
  * A {@link org.apache.lucene.index.FilterLeafReader} that exposes
  * OpenSearch internal per shard / index information like the shard ID.
+ *
+ * @opensearch.internal
  */
 public final class OpenSearchLeafReader extends SequentialStoredFieldsLeafReader {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/SequentialStoredFieldsLeafReader.java b/server/src/main/java/org/opensearch/common/lucene/index/SequentialStoredFieldsLeafReader.java
index 73c6e1e73f897..3e6630af074fd 100644
--- a/server/src/main/java/org/opensearch/common/lucene/index/SequentialStoredFieldsLeafReader.java
+++ b/server/src/main/java/org/opensearch/common/lucene/index/SequentialStoredFieldsLeafReader.java
@@ -45,6 +45,8 @@
  * {@link FilterLeafReader} that are used at search time in order to
  * leverage sequential access when retrieving stored fields in queries,
  * aggregations or during the fetch phase.
+ *
+ * @opensearch.internal
  */
 public abstract class SequentialStoredFieldsLeafReader extends FilterLeafReader {
     /**
diff --git a/server/src/main/java/org/opensearch/common/lucene/index/package-info.java b/server/src/main/java/org/opensearch/common/lucene/index/package-info.java
new file mode 100644
index 0000000000000..c605aec31752c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/index/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch Lucene Index package. */
+package org.opensearch.common.lucene.index;
diff --git a/server/src/main/java/org/opensearch/common/lucene/package-info.java b/server/src/main/java/org/opensearch/common/lucene/package-info.java
new file mode 100644
index 0000000000000..845f99788cb83
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Common OpenSearch Lucene implementation package. */
+package org.opensearch.common.lucene;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java b/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
index 9755a99fecc08..ada5bc0598478 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/AutomatonQueries.java
@@ -34,6 +34,7 @@
 
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.AutomatonQuery;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
@@ -46,6 +47,8 @@
 
 /**
  * Helper functions for creating various forms of {@link AutomatonQuery}
+ *
+ * @opensearch.internal
  */
 public class AutomatonQueries {
 
@@ -63,29 +66,58 @@ public static Automaton caseInsensitivePrefix(String s) {
         return a;
     }
 
-    /** Build an automaton query accepting all terms with the specified prefix, ASCII case insensitive. */
+    /**
+     * Build an automaton query accepting all terms with the specified prefix, ASCII case insensitive.
+     */
     public static AutomatonQuery caseInsensitivePrefixQuery(Term prefix) {
-        return new AutomatonQuery(prefix, caseInsensitivePrefix(prefix.text()));
+        return caseInsensitivePrefixQuery(prefix, MultiTermQuery.CONSTANT_SCORE_REWRITE);
+    }
+
+    /**
+     * Build an automaton query accepting all terms with the specified prefix, ASCII case insensitive.
+     */
+    public static AutomatonQuery caseInsensitivePrefixQuery(Term prefix, MultiTermQuery.RewriteMethod method) {
+        return createAutomatonQuery(prefix, caseInsensitivePrefix(prefix.text()), method);
     }
 
-    /** Build an automaton accepting all terms ASCII case insensitive. */
+    /**
+     * Build an automaton accepting all terms ASCII case insensitive.
+     */
     public static AutomatonQuery caseInsensitiveTermQuery(Term term) {
         BytesRef prefix = term.bytes();
         return new AutomatonQuery(term, toCaseInsensitiveString(prefix, Integer.MAX_VALUE));
     }
 
-    /** Build an automaton matching a wildcard pattern, ASCII case insensitive. */
-    public static AutomatonQuery caseInsensitiveWildcardQuery(Term wildcardquery) {
-        return new AutomatonQuery(wildcardquery, toCaseInsensitiveWildcardAutomaton(wildcardquery, Integer.MAX_VALUE));
+    /**
+     * Build an automaton matching a wildcard pattern, ASCII case insensitive, if the method is null, then will use {@link  MultiTermQuery#CONSTANT_SCORE_REWRITE}.
+     */
+    public static AutomatonQuery caseInsensitiveWildcardQuery(Term wildcardquery, MultiTermQuery.RewriteMethod method) {
+        return createAutomatonQuery(wildcardquery, toCaseInsensitiveWildcardAutomaton(wildcardquery, Integer.MAX_VALUE), method);
     }
 
-    /** String equality with support for wildcards */
+    /**
+     * Build an automaton matching a given pattern with rewrite method, if the rewrite method is null, then will use {@link  MultiTermQuery#CONSTANT_SCORE_REWRITE}.
+     */
+    public static AutomatonQuery createAutomatonQuery(Term term, Automaton automaton, MultiTermQuery.RewriteMethod method) {
+        if (method == null) {
+            method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
+        }
+        return new AutomatonQuery(term, automaton, Operations.DEFAULT_DETERMINIZE_WORK_LIMIT, false, method);
+    }
+
+    /**
+     * String equality with support for wildcards
+     */
     public static final char WILDCARD_STRING = '*';
 
-    /** Char equality with support for wildcards */
+    /**
+     * Char equality with support for wildcards
+     */
     public static final char WILDCARD_CHAR = '?';
 
-    /** Escape character */
+    /**
+     * Escape character
+     */
     public static final char WILDCARD_ESCAPE = '\\';
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/FilteredCollector.java b/server/src/main/java/org/opensearch/common/lucene/search/FilteredCollector.java
index 331b67a40878f..0d7a8866f7788 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/FilteredCollector.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/FilteredCollector.java
@@ -43,6 +43,11 @@
 
 import java.io.IOException;
 
+/**
+ * A filtered collector.
+ *
+ * @opensearch.internal
+ */
 public class FilteredCollector implements Collector {
 
     private final Collector collector;
@@ -53,6 +58,10 @@ public FilteredCollector(Collector collector, Weight filter) {
         this.filter = filter;
     }
 
+    public Collector getCollector() {
+        return collector;
+    }
+
     @Override
     public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
         final ScorerSupplier filterScorerSupplier = filter.scorerSupplier(context);
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/MoreLikeThisQuery.java b/server/src/main/java/org/opensearch/common/lucene/search/MoreLikeThisQuery.java
index bc83f07f74103..ef07f6ea8052c 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/MoreLikeThisQuery.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/MoreLikeThisQuery.java
@@ -36,19 +36,19 @@
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.index.Fields;
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.similarities.ClassicSimilarity;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.search.similarities.TFIDFSimilarity;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -59,6 +59,11 @@
 import java.util.Objects;
 import java.util.Set;
 
+/**
+ * The more like this query.
+ *
+ * @opensearch.internal
+ */
 public class MoreLikeThisQuery extends Query {
 
     public static final String DEFAULT_MINIMUM_SHOULD_MATCH = "30%";
@@ -139,12 +144,12 @@ public boolean equals(Object obj) {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query rewritten = super.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query rewritten = super.rewrite(searcher);
         if (rewritten != this) {
             return rewritten;
         }
-        XMoreLikeThis mlt = new XMoreLikeThis(reader, similarity == null ? new ClassicSimilarity() : similarity);
+        XMoreLikeThis mlt = new XMoreLikeThis(searcher.getIndexReader(), similarity == null ? new ClassicSimilarity() : similarity);
 
         mlt.setFieldNames(moreLikeFields);
         mlt.setAnalyzer(analyzer);
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/MultiPhrasePrefixQuery.java b/server/src/main/java/org/opensearch/common/lucene/search/MultiPhrasePrefixQuery.java
index 982779333e7da..d97f1db61daea 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/MultiPhrasePrefixQuery.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/MultiPhrasePrefixQuery.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.common.lucene.search;
 
-import com.carrotsearch.hppc.ObjectHashSet;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Term;
@@ -40,6 +39,7 @@
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.MultiPhraseQuery;
 import org.apache.lucene.search.Query;
@@ -50,11 +50,18 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Objects;
+import java.util.Set;
 
+/**
+ * A multi phrase prefix query.
+ *
+ * @opensearch.internal
+ */
 public class MultiPhrasePrefixQuery extends Query {
 
     private final String field;
@@ -153,8 +160,8 @@ public int[] getPositions() {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query rewritten = super.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query rewritten = super.rewrite(searcher);
         if (rewritten != this) {
             return rewritten;
         }
@@ -169,9 +176,9 @@ public Query rewrite(IndexReader reader) throws IOException {
         }
         Term[] suffixTerms = termArrays.get(sizeMinus1);
         int position = positions.get(sizeMinus1);
-        ObjectHashSet<Term> terms = new ObjectHashSet<>();
+        Set<Term> terms = new HashSet<>();
         for (Term term : suffixTerms) {
-            getPrefixTerms(terms, term, reader);
+            getPrefixTerms(terms, term, searcher.getIndexReader());
             if (terms.size() > maxExpansions) {
                 break;
             }
@@ -191,11 +198,11 @@ public Query rewrite(IndexReader reader) throws IOException {
                 )
                 .build();
         }
-        query.add(terms.toArray(Term.class), position);
+        query.add(terms.toArray(new Term[0]), position);
         return query.build();
     }
 
-    private void getPrefixTerms(ObjectHashSet<Term> terms, final Term prefix, final IndexReader reader) throws IOException {
+    private void getPrefixTerms(final Set<Term> terms, final Term prefix, final IndexReader reader) throws IOException {
         // SlowCompositeReaderWrapper could be used... but this would merge all terms from each segment into one terms
         // instance, which is very expensive. Therefore I think it is better to iterate over each leaf individually.
         List<LeafReaderContext> leaves = reader.leaves();
@@ -324,6 +331,20 @@ public String getField() {
 
     @Override
     public void visit(QueryVisitor visitor) {
-        visitor.visitLeaf(this);
+        if (visitor.acceptField(field)) {
+            // set by the subvisitor because the default returns, *this*, unless MUST_NOT is used which returns
+            // an ideal EMPTY_VISITOR
+            visitor = visitor.getSubVisitor(BooleanClause.Occur.MUST, this);
+            for (int i = 0; i < termArrays.size() - 1; ++i) {
+                if (termArrays.get(i).length == 1) {
+                    visitor.consumeTerms(this, termArrays.get(i)[0]); // use a must if we only have a single phrase
+                } else {
+                    // if more than one sub-phrase
+                    // we should match at least one
+                    QueryVisitor subVisitor = visitor.getSubVisitor(BooleanClause.Occur.SHOULD, this);
+                    subVisitor.consumeTerms(this, termArrays.get(i));
+                }
+            }
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/Queries.java b/server/src/main/java/org/opensearch/common/lucene/search/Queries.java
index 2f500efba9e8e..8b64a45b9db25 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/Queries.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/Queries.java
@@ -33,7 +33,6 @@
 package org.opensearch.common.lucene.search;
 
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.ExtendedCommonTermsQuery;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanClause.Occur;
@@ -43,17 +42,14 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
-import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.Weight;
-import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -62,6 +58,11 @@
 import java.util.Objects;
 import java.util.regex.Pattern;
 
+/**
+ * Lucene queries class
+ *
+ * @opensearch.internal
+ */
 public class Queries {
 
     public static Query newMatchAllQuery() {
@@ -87,7 +88,7 @@ public static Query newLenientFieldQuery(String field, RuntimeException e) {
     }
 
     public static Query newNestedFilter() {
-        return new PrefixQuery(new Term(TypeFieldMapper.NAME, new BytesRef("__")));
+        return not(newNonNestedFilter());
     }
 
     /**
@@ -214,6 +215,11 @@ public static Query newMatchNoDocsQueryWithoutRewrite(String reason) {
         return new MatchNoDocsWithoutRewriteQuery(reason);
     }
 
+    /**
+     * Matches no docs w/o rewriting the query
+     *
+     * @opensearch.internal
+     */
     static class MatchNoDocsWithoutRewriteQuery extends Query {
         private final String reason;
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/SpanBooleanQueryRewriteWithMaxClause.java b/server/src/main/java/org/opensearch/common/lucene/search/SpanBooleanQueryRewriteWithMaxClause.java
index 4b770529af4a8..65cffa208a47f 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/SpanBooleanQueryRewriteWithMaxClause.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/SpanBooleanQueryRewriteWithMaxClause.java
@@ -59,6 +59,8 @@
  * that match the {@link MultiTermQuery} in the terms dictionary.
  * The rewrite throws an error if more than <code>maxExpansions</code> terms are found and <code>hardLimit</code>
  * is set.
+ *
+ * @opensearch.internal
  */
 public class SpanBooleanQueryRewriteWithMaxClause extends SpanMultiTermQueryWrapper.SpanRewriteMethod {
     private final int maxExpansions;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/TopDocsAndMaxScore.java b/server/src/main/java/org/opensearch/common/lucene/search/TopDocsAndMaxScore.java
index b7976058afcf6..5f8c52676b481 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/TopDocsAndMaxScore.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/TopDocsAndMaxScore.java
@@ -36,6 +36,8 @@
 
 /**
  * Wrapper around a {@link TopDocs} instance and the maximum score.
+ *
+ * @opensearch.internal
  */
 // TODO: Remove this class when https://github.com/elastic/elasticsearch/issues/32981 is addressed.
 public final class TopDocsAndMaxScore {
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/XMoreLikeThis.java b/server/src/main/java/org/opensearch/common/lucene/search/XMoreLikeThis.java
index 63e6304fa50e5..7149eeab8f3ed 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/XMoreLikeThis.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/XMoreLikeThis.java
@@ -56,7 +56,9 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.PostingsEnum;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermVectors;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BooleanClause;
@@ -165,6 +167,8 @@
  * - refactor: moved common code into isNoiseWord()
  * - optimise: when no termvector support available - used maxNumTermsParsed to limit amount of tokenization
  * </pre>
+ *
+ * @opensearch.internal
  */
 public final class XMoreLikeThis {
 
@@ -806,8 +810,10 @@ public String describeParams() {
      */
     private PriorityQueue<ScoreTerm> retrieveTerms(int docNum) throws IOException {
         Map<String, Int> termFreqMap = new HashMap<>();
+        final TermVectors termVectors = ir.termVectors();
+        final StoredFields storedFields = ir.storedFields();
         for (String fieldName : fieldNames) {
-            final Fields vectors = ir.getTermVectors(docNum);
+            final Fields vectors = termVectors.get(docNum);
             final Terms vector;
             if (vectors != null) {
                 vector = vectors.terms(fieldName);
@@ -817,7 +823,7 @@ private PriorityQueue<ScoreTerm> retrieveTerms(int docNum) throws IOException {
 
             // field does not store term vector info
             if (vector == null) {
-                Document d = ir.document(docNum);
+                Document d = storedFields.document(docNum);
                 IndexableField fields[] = d.getFields(fieldName);
                 for (IndexableField field : fields) {
                     final String stringValue = field.stringValue();
@@ -1016,6 +1022,8 @@ public String[] retrieveInterestingTerms(Reader r, String fieldName) throws IOEx
 
     /**
      * PriorityQueue that orders words by score.
+     *
+     * @opensearch.internal
      */
     private static class FreqQ extends PriorityQueue<ScoreTerm> {
         FreqQ(int maxSize) {
@@ -1028,6 +1036,11 @@ protected boolean lessThan(ScoreTerm a, ScoreTerm b) {
         }
     }
 
+    /**
+     * A scored term
+     *
+     * @opensearch.internal
+     */
     private static class ScoreTerm {
         String word;
         String topField;
@@ -1048,6 +1061,8 @@ void update(String word, String topField, float score) {
 
     /**
      * Use for frequencies and to avoid renewing Integers.
+     *
+     * @opensearch.internal
      */
     private static class Int {
         int x;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/CombineFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/CombineFunction.java
index 3e0a6f59b4e1a..60197ccf93af9 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/CombineFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/CombineFunction.java
@@ -33,13 +33,18 @@
 package org.opensearch.common.lucene.search.function;
 
 import org.apache.lucene.search.Explanation;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 
+/**
+ * Combine function for search
+ *
+ * @opensearch.internal
+ */
 public enum CombineFunction implements Writeable {
     MULTIPLY {
         @Override
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/FieldValueFactorFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/FieldValueFactorFunction.java
index 3233fc9f8cecc..ee5d7424d1b71 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/FieldValueFactorFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/FieldValueFactorFunction.java
@@ -36,9 +36,9 @@
 import org.apache.lucene.search.Explanation;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
@@ -51,6 +51,8 @@
  * A function_score function that multiplies the score with the value of a
  * field from the document, optionally multiplying the field by a factor first,
  * and applying a modification (log, ln, sqrt, square, etc) afterwards.
+ *
+ * @opensearch.internal
  */
 public class FieldValueFactorFunction extends ScoreFunction {
     private final String field;
@@ -174,6 +176,8 @@ protected int doHashCode() {
     /**
      * The Type class encapsulates the modification types that can be applied
      * to the score/value product.
+     *
+     * @opensearch.internal
      */
     public enum Modifier implements Writeable {
         NONE {
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/FunctionScoreQuery.java b/server/src/main/java/org/opensearch/common/lucene/search/function/FunctionScoreQuery.java
index 09239b0108422..cb93e80288a98 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/FunctionScoreQuery.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/FunctionScoreQuery.java
@@ -46,10 +46,10 @@
 import org.apache.lucene.util.Bits;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -62,10 +62,17 @@
 /**
  * A query that allows for a pluggable boost function / filter. If it matches
  * the filter, it will be boosted by the formula.
+ *
+ * @opensearch.internal
  */
 public class FunctionScoreQuery extends Query {
     public static final float DEFAULT_MAX_BOOST = Float.MAX_VALUE;
 
+    /**
+     * Filter score function
+     *
+     * @opensearch.internal
+     */
     public static class FilterScoreFunction extends ScoreFunction {
         public final Query filter;
         public final ScoreFunction function;
@@ -121,7 +128,7 @@ protected int doHashCode() {
 
         @Override
         protected ScoreFunction rewrite(IndexReader reader) throws IOException {
-            Query newFilter = filter.rewrite(reader);
+            Query newFilter = filter.rewrite(new IndexSearcher(reader));
             if (newFilter == filter) {
                 return this;
             }
@@ -134,6 +141,11 @@ public float getWeight() {
         }
     }
 
+    /**
+     * The mode of the score
+     *
+     * @opensearch.internal
+     */
     public enum ScoreMode implements Writeable {
         FIRST,
         AVG,
@@ -310,16 +322,16 @@ public void visit(QueryVisitor visitor) {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query rewritten = super.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query rewritten = super.rewrite(searcher);
         if (rewritten != this) {
             return rewritten;
         }
-        Query newQ = subQuery.rewrite(reader);
+        Query newQ = subQuery.rewrite(searcher);
         ScoreFunction[] newFunctions = new ScoreFunction[functions.length];
         boolean needsRewrite = (newQ != subQuery);
         for (int i = 0; i < functions.length; i++) {
-            newFunctions[i] = functions[i].rewrite(reader);
+            newFunctions[i] = functions[i].rewrite(searcher.getIndexReader());
             needsRewrite |= (newFunctions[i] != functions[i]);
         }
         if (needsRewrite) {
@@ -481,6 +493,11 @@ public boolean isCacheable(LeafReaderContext ctx) {
         }
     }
 
+    /**
+     * Internal function factor scorer
+     *
+     * @opensearch.internal
+     */
     static class FunctionFactorScorer extends FilterScorer {
         private final ScoreFunction[] functions;
         private final ScoreMode scoreMode;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/Functions.java b/server/src/main/java/org/opensearch/common/lucene/search/function/Functions.java
index a9de8ead31e2a..a5f4f8ce465b3 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/Functions.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/Functions.java
@@ -9,12 +9,14 @@
 package org.opensearch.common.lucene.search.function;
 
 import org.apache.lucene.search.Explanation;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;
 
 /**
  * Helper utility class for functions
+ *
+ * @opensearch.internal
  */
 public final class Functions {
     private Functions() {}
@@ -25,7 +27,7 @@ private Functions() {}
      * @return function name wrapped into brackets or empty string
      */
     public static String nameOrEmptyFunc(final String functionName) {
-        if (!Strings.isNullOrEmpty(functionName)) {
+        if (Strings.isNullOrEmpty(functionName) == false) {
             return "(" + AbstractQueryBuilder.NAME_FIELD.getPreferredName() + ": " + functionName + ")";
         } else {
             return "";
@@ -38,7 +40,7 @@ public static String nameOrEmptyFunc(final String functionName) {
      * @return function name as an argument or empty string
      */
     public static String nameOrEmptyArg(final String functionName) {
-        if (!Strings.isNullOrEmpty(functionName)) {
+        if (Strings.isNullOrEmpty(functionName) == false) {
             return ", " + FunctionScoreQueryBuilder.NAME_FIELD.getPreferredName() + ": " + functionName;
         } else {
             return "";
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/LeafScoreFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/LeafScoreFunction.java
index ad3c5b8031dd7..4ff283730a9a1 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/LeafScoreFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/LeafScoreFunction.java
@@ -36,7 +36,11 @@
 
 import java.io.IOException;
 
-/** Per-leaf {@link ScoreFunction}. */
+/**
+ * Per-leaf {@link ScoreFunction}.
+ *
+ * @opensearch.internal
+ */
 public abstract class LeafScoreFunction {
 
     public abstract double score(int docId, float subQueryScore) throws IOException;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/MinScoreScorer.java b/server/src/main/java/org/opensearch/common/lucene/search/function/MinScoreScorer.java
index 368c41a149b63..30be06489dea5 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/MinScoreScorer.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/MinScoreScorer.java
@@ -39,8 +39,12 @@
 
 import java.io.IOException;
 
-/** A {@link Scorer} that filters out documents that have a score that is
- *  lower than a configured constant. */
+/**
+ * A {@link Scorer} that filters out documents that have a score that is
+ * lower than a configured constant.
+ *
+ *  @opensearch.internal
+ */
 final class MinScoreScorer extends Scorer {
 
     private final Scorer in;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/RandomScoreFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/RandomScoreFunction.java
index f4fcda47b0078..b743a7bd3e707 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/RandomScoreFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/RandomScoreFunction.java
@@ -31,11 +31,11 @@
 
 package org.opensearch.common.lucene.search.function;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.util.StringHelper;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.util.BitMixer;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
@@ -45,6 +45,8 @@
 
 /**
  * Pseudo randomly generate a score for each {@link LeafScoreFunction#score}.
+ *
+ * @opensearch.internal
  */
 public class RandomScoreFunction extends ScoreFunction {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/ScoreFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/ScoreFunction.java
index 48200d9dbacff..fe01e8489d61f 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/ScoreFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/ScoreFunction.java
@@ -38,6 +38,11 @@
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Score function for search.
+ *
+ * @opensearch.internal
+ */
 public abstract class ScoreFunction {
 
     private final CombineFunction scoreCombiner;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreFunction.java
index 3a7cc970908a5..38c356a8be4b0 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreFunction.java
@@ -35,15 +35,20 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.Scorable;
+import org.opensearch.Version;
+import org.opensearch.common.Nullable;
 import org.opensearch.script.ExplainableScoreScript;
 import org.opensearch.script.ScoreScript;
 import org.opensearch.script.Script;
-import org.opensearch.Version;
-import org.opensearch.common.Nullable;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Script score function for search.
+ *
+ * @opensearch.internal
+ */
 public class ScriptScoreFunction extends ScoreFunction {
 
     static final class CannedScorer extends Scorable {
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreQuery.java b/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreQuery.java
index 846cfd4b6431e..90350c0a21a42 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreQuery.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/ScriptScoreQuery.java
@@ -32,21 +32,20 @@
 
 package org.opensearch.common.lucene.search.function;
 
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.BulkScorer;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.FilterLeafCollector;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.LeafCollector;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.Scorable;
-import org.apache.lucene.search.Weight;
-import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.QueryVisitor;
+import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
-import org.apache.lucene.search.BulkScorer;
+import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.Bits;
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
@@ -59,6 +58,8 @@
 
 /**
  * A query that uses a script to compute documents' scores.
+ *
+ * @opensearch.internal
  */
 public class ScriptScoreQuery extends Query {
     private final Query subQuery;
@@ -103,12 +104,12 @@ public ScriptScoreQuery(
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query newQ = subQuery.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query newQ = subQuery.rewrite(searcher);
         if (newQ != subQuery) {
             return new ScriptScoreQuery(newQ, queryName, script, scriptBuilder, minScore, indexName, shardId, indexVersion);
         }
-        return super.rewrite(reader);
+        return super.rewrite(searcher);
     }
 
     @Override
@@ -244,6 +245,11 @@ public int hashCode() {
         return Objects.hash(subQuery, script, minScore, indexName, shardId, indexVersion, queryName);
     }
 
+    /**
+     * A script scorer
+     *
+     * @opensearch.internal
+     */
     private static class ScriptScorer extends Scorer {
         private final ScoreScript scoreScript;
         private final Scorer subQueryScorer;
@@ -303,6 +309,11 @@ public float getMaxScore(int upTo) {
 
     }
 
+    /**
+     * A script scorable
+     *
+     * @opensearch.internal
+     */
     private static class ScriptScorable extends Scorable {
         private final ScoreScript scoreScript;
         private final Scorable subQueryScorer;
@@ -352,6 +363,8 @@ public int docID() {
     /**
      * Use the {@link BulkScorer} of the sub-query,
      * as it may be significantly faster (e.g. BooleanScorer) than iterating over the scorer
+     *
+     * @opensearch.internal
      */
     private static class ScriptScoreBulkScorer extends BulkScorer {
         private final BulkScorer subQueryBulkScorer;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/WeightFactorFunction.java b/server/src/main/java/org/opensearch/common/lucene/search/function/WeightFactorFunction.java
index 71968a0545cff..84ef6e308092e 100644
--- a/server/src/main/java/org/opensearch/common/lucene/search/function/WeightFactorFunction.java
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/WeightFactorFunction.java
@@ -35,11 +35,16 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Explanation;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Weight factor function
+ *
+ * @opensearch.internal
+ */
 public class WeightFactorFunction extends ScoreFunction {
 
     private static final ScoreFunction SCORE_ONE = new ScoreOne(CombineFunction.MULTIPLY);
@@ -123,6 +128,11 @@ protected int doHashCode() {
         return Objects.hash(weight, scoreFunction);
     }
 
+    /**
+     * A constant score of 1.0
+     *
+     * @opensearch.internal
+     */
     private static class ScoreOne extends ScoreFunction {
         private final String functionName;
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/function/package-info.java b/server/src/main/java/org/opensearch/common/lucene/search/function/package-info.java
new file mode 100644
index 0000000000000..c24e917137415
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/search/function/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Lucene Function Scoring package. */
+package org.opensearch.common.lucene.search.function;
diff --git a/server/src/main/java/org/opensearch/common/lucene/search/package-info.java b/server/src/main/java/org/opensearch/common/lucene/search/package-info.java
new file mode 100644
index 0000000000000..e60b632a11d33
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/search/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base OpenSearch Specific Lucene Query package. */
+package org.opensearch.common.lucene.search;
diff --git a/server/src/main/java/org/opensearch/common/lucene/store/ByteArrayIndexInput.java b/server/src/main/java/org/opensearch/common/lucene/store/ByteArrayIndexInput.java
index ed352fbf208b3..6eb613daf5133 100644
--- a/server/src/main/java/org/opensearch/common/lucene/store/ByteArrayIndexInput.java
+++ b/server/src/main/java/org/opensearch/common/lucene/store/ByteArrayIndexInput.java
@@ -32,21 +32,24 @@
 package org.opensearch.common.lucene.store;
 
 import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.RandomAccessInput;
 
 import java.io.EOFException;
 import java.io.IOException;
 
 /**
  * Wraps array of bytes into IndexInput
+ *
+ * @opensearch.internal
  */
-public class ByteArrayIndexInput extends IndexInput {
+public class ByteArrayIndexInput extends IndexInput implements RandomAccessInput {
     private final byte[] bytes;
 
-    private int pos;
+    private final int offset;
 
-    private int offset;
+    private final int length;
 
-    private int length;
+    private int pos;
 
     public ByteArrayIndexInput(String resourceDesc, byte[] bytes) {
         this(resourceDesc, bytes, 0, bytes.length);
@@ -104,18 +107,66 @@ public IndexInput slice(String sliceDescription, long offset, long length) throw
 
     @Override
     public byte readByte() throws IOException {
-        if (pos >= offset + length) {
-            throw new EOFException("seek past EOF");
-        }
+        validatePos(pos, Byte.BYTES);
         return bytes[offset + pos++];
     }
 
     @Override
     public void readBytes(final byte[] b, final int offset, int len) throws IOException {
-        if (pos + len > this.offset + length) {
-            throw new EOFException("seek past EOF");
-        }
+        validatePos(pos, len);
         System.arraycopy(bytes, this.offset + pos, b, offset, len);
         pos += len;
     }
+
+    @Override
+    public byte readByte(long pos) throws IOException {
+        validatePos(pos, Byte.BYTES);
+        return internalReadByte(pos);
+    }
+
+    @Override
+    public short readShort(long pos) throws IOException {
+        validatePos(pos, Short.BYTES);
+        return internalReadShort(pos);
+    }
+
+    @Override
+    public int readInt(long pos) throws IOException {
+        validatePos(pos, Integer.BYTES);
+        return internalReadInt(pos);
+    }
+
+    @Override
+    public long readLong(long pos) throws IOException {
+        validatePos(pos, Long.BYTES);
+        return internalReadLong(pos);
+    }
+
+    private byte internalReadByte(long pos) {
+        return bytes[offset + (int) pos];
+    }
+
+    private short internalReadShort(long pos) {
+        final byte p1 = internalReadByte(pos);
+        final byte p2 = internalReadByte(pos + 1);
+        return (short) (((p2 & 0xFF) << 8) | (p1 & 0xFF));
+    }
+
+    private int internalReadInt(long pos) {
+        final short p1 = internalReadShort(pos);
+        final short p2 = internalReadShort(pos + Short.BYTES);
+        return ((p2 & 0xFFFF) << 16) | (p1 & 0xFFFF);
+    }
+
+    public long internalReadLong(long pos) {
+        final int p1 = internalReadInt(pos);
+        final int p2 = internalReadInt(pos + Integer.BYTES);
+        return (((long) p2) << 32) | (p1 & 0xFFFFFFFFL);
+    }
+
+    private void validatePos(long pos, int len) throws EOFException {
+        if (pos < 0 || pos + len > length + offset) {
+            throw new EOFException("seek past EOF");
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/lucene/store/FilterIndexOutput.java b/server/src/main/java/org/opensearch/common/lucene/store/FilterIndexOutput.java
index e23cedf86eaa7..618e02e9546b2 100644
--- a/server/src/main/java/org/opensearch/common/lucene/store/FilterIndexOutput.java
+++ b/server/src/main/java/org/opensearch/common/lucene/store/FilterIndexOutput.java
@@ -37,6 +37,8 @@
 
 /**
  * IndexOutput that delegates all calls to another IndexOutput
+ *
+ * @opensearch.internal
  */
 public class FilterIndexOutput extends IndexOutput {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/store/IndexOutputOutputStream.java b/server/src/main/java/org/opensearch/common/lucene/store/IndexOutputOutputStream.java
index d0d776c816da2..f71b0d3e3617d 100644
--- a/server/src/main/java/org/opensearch/common/lucene/store/IndexOutputOutputStream.java
+++ b/server/src/main/java/org/opensearch/common/lucene/store/IndexOutputOutputStream.java
@@ -39,6 +39,8 @@
 
 /**
  * {@link OutputStream} that writes into underlying IndexOutput
+ *
+ * @opensearch.internal
  */
 public class IndexOutputOutputStream extends OutputStream {
 
diff --git a/server/src/main/java/org/opensearch/common/lucene/store/InputStreamIndexInput.java b/server/src/main/java/org/opensearch/common/lucene/store/InputStreamIndexInput.java
index 47e454b6f755c..71075de0037e2 100644
--- a/server/src/main/java/org/opensearch/common/lucene/store/InputStreamIndexInput.java
+++ b/server/src/main/java/org/opensearch/common/lucene/store/InputStreamIndexInput.java
@@ -37,6 +37,11 @@
 import java.io.IOException;
 import java.io.InputStream;
 
+/**
+ * Index input over an input stream.
+ *
+ * @opensearch.internal
+ */
 public class InputStreamIndexInput extends InputStream {
 
     private final IndexInput indexInput;
diff --git a/server/src/main/java/org/opensearch/common/lucene/store/package-info.java b/server/src/main/java/org/opensearch/common/lucene/store/package-info.java
new file mode 100644
index 0000000000000..3d46f3be44b9b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/store/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch specific lucene store package. */
+package org.opensearch.common.lucene.store;
diff --git a/server/src/main/java/org/opensearch/common/lucene/uid/PerThreadIDVersionAndSeqNoLookup.java b/server/src/main/java/org/opensearch/common/lucene/uid/PerThreadIDVersionAndSeqNoLookup.java
index 362badf046b75..60d1f9e41ea2c 100644
--- a/server/src/main/java/org/opensearch/common/lucene/uid/PerThreadIDVersionAndSeqNoLookup.java
+++ b/server/src/main/java/org/opensearch/common/lucene/uid/PerThreadIDVersionAndSeqNoLookup.java
@@ -61,6 +61,8 @@
  *  This class uses live docs, so it should be cached based on the
  *  {@link org.apache.lucene.index.IndexReader#getReaderCacheHelper() reader cache helper}
  *  rather than the {@link LeafReader#getCoreCacheHelper() core cache helper}.
+ *
+ *  @opensearch.internal
  */
 final class PerThreadIDVersionAndSeqNoLookup {
     // TODO: do we really need to store all this stuff? some if it might not speed up anything.
diff --git a/server/src/main/java/org/opensearch/common/lucene/uid/Versions.java b/server/src/main/java/org/opensearch/common/lucene/uid/Versions.java
index bd10085c0153f..09b9a7e3e692d 100644
--- a/server/src/main/java/org/opensearch/common/lucene/uid/Versions.java
+++ b/server/src/main/java/org/opensearch/common/lucene/uid/Versions.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.lucene.uid;
 
+/**
+ * UID versions.
+ *
+ * @opensearch.internal
+ */
 public final class Versions {
 
     /** used to indicate the write operation should succeed regardless of current version **/
diff --git a/server/src/main/java/org/opensearch/common/lucene/uid/VersionsAndSeqNoResolver.java b/server/src/main/java/org/opensearch/common/lucene/uid/VersionsAndSeqNoResolver.java
index bea9c7b6bdc8c..57524bc3657d9 100644
--- a/server/src/main/java/org/opensearch/common/lucene/uid/VersionsAndSeqNoResolver.java
+++ b/server/src/main/java/org/opensearch/common/lucene/uid/VersionsAndSeqNoResolver.java
@@ -44,7 +44,11 @@
 import java.util.Objects;
 import java.util.concurrent.ConcurrentMap;
 
-/** Utility class to resolve the Lucene doc ID, version, seqNo and primaryTerms for a given uid. */
+/**
+ * Utility class to resolve the Lucene doc ID, version, seqNo and primaryTerms for a given uid.
+ *
+ * @opensearch.internal
+ */
 public final class VersionsAndSeqNoResolver {
 
     static final ConcurrentMap<IndexReader.CacheKey, CloseableThreadLocal<PerThreadIDVersionAndSeqNoLookup[]>> lookupStates =
@@ -103,7 +107,11 @@ private static PerThreadIDVersionAndSeqNoLookup[] getLookupState(IndexReader rea
 
     private VersionsAndSeqNoResolver() {}
 
-    /** Wraps an {@link LeafReaderContext}, a doc ID <b>relative to the context doc base</b> and a version. */
+    /**
+     * Wraps an {@link LeafReaderContext}, a doc ID <b>relative to the context doc base</b> and a version.
+     *
+     * @opensearch.internal
+     */
     public static class DocIdAndVersion {
         public final int docId;
         public final long version;
@@ -122,7 +130,11 @@ public DocIdAndVersion(int docId, long version, long seqNo, long primaryTerm, Le
         }
     }
 
-    /** Wraps an {@link LeafReaderContext}, a doc ID <b>relative to the context doc base</b> and a seqNo. */
+    /**
+     * Wraps an {@link LeafReaderContext}, a doc ID <b>relative to the context doc base</b> and a seqNo.
+     *
+     * @opensearch.internal
+     */
     public static class DocIdAndSeqNo {
         public final int docId;
         public final long seqNo;
diff --git a/server/src/main/java/org/opensearch/common/lucene/uid/package-info.java b/server/src/main/java/org/opensearch/common/lucene/uid/package-info.java
new file mode 100644
index 0000000000000..46d28f9c416e9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/lucene/uid/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch specific lucene sequence numbers package. */
+package org.opensearch.common.lucene.uid;
diff --git a/server/src/main/java/org/opensearch/common/metrics/CounterMetric.java b/server/src/main/java/org/opensearch/common/metrics/CounterMetric.java
index 5d0b21df21a08..cb181840406a5 100644
--- a/server/src/main/java/org/opensearch/common/metrics/CounterMetric.java
+++ b/server/src/main/java/org/opensearch/common/metrics/CounterMetric.java
@@ -34,6 +34,11 @@
 
 import java.util.concurrent.atomic.LongAdder;
 
+/**
+ * A counter metric for tracking.
+ *
+ * @opensearch.internal
+ */
 public class CounterMetric implements Metric {
 
     private final LongAdder counter = new LongAdder();
@@ -57,4 +62,5 @@ public void dec(long n) {
     public long count() {
         return counter.sum();
     }
+
 }
diff --git a/server/src/main/java/org/opensearch/common/metrics/MeanMetric.java b/server/src/main/java/org/opensearch/common/metrics/MeanMetric.java
index 977d8e62a3411..359facdce633b 100644
--- a/server/src/main/java/org/opensearch/common/metrics/MeanMetric.java
+++ b/server/src/main/java/org/opensearch/common/metrics/MeanMetric.java
@@ -34,6 +34,11 @@
 
 import java.util.concurrent.atomic.LongAdder;
 
+/**
+ * An average metric for tracking.
+ *
+ * @opensearch.internal
+ */
 public class MeanMetric implements Metric {
 
     private final LongAdder counter = new LongAdder();
@@ -44,6 +49,11 @@ public void inc(long n) {
         sum.add(n);
     }
 
+    public void add(MeanMetric other) {
+        counter.add(other.counter.sum());
+        sum.add(other.sum.sum());
+    }
+
     public void dec(long n) {
         counter.decrement();
         sum.add(-n);
@@ -69,4 +79,5 @@ public void clear() {
         counter.reset();
         sum.reset();
     }
+
 }
diff --git a/server/src/main/java/org/opensearch/common/metrics/Metric.java b/server/src/main/java/org/opensearch/common/metrics/Metric.java
index f56d1dd0e7fad..f39de634ec477 100644
--- a/server/src/main/java/org/opensearch/common/metrics/Metric.java
+++ b/server/src/main/java/org/opensearch/common/metrics/Metric.java
@@ -32,4 +32,9 @@
 
 package org.opensearch.common.metrics;
 
+/**
+ * Base metric.
+ *
+ * @opensearch.internal
+ */
 public interface Metric {}
diff --git a/server/src/main/java/org/opensearch/common/metrics/OperationMetrics.java b/server/src/main/java/org/opensearch/common/metrics/OperationMetrics.java
new file mode 100644
index 0000000000000..97fbbc2ce5cde
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/metrics/OperationMetrics.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.metrics;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Mutable tracker of a repeated operation.
+ *
+ * @opensearch.internal
+ */
+public class OperationMetrics {
+    /**
+     * The mean time it takes to complete the measured item.
+     */
+    private final MeanMetric time = new MeanMetric();
+    /**
+     * The current count of things being measured.
+     * Useful when aggregating multiple metrics to see how many things are in flight.
+     */
+    private final AtomicLong current = new AtomicLong();
+    /**
+     * The non-decreasing count of failures
+     */
+    private final CounterMetric failed = new CounterMetric();
+
+    /**
+     * Invoked before the given operation begins.
+     */
+    public void before() {
+        current.incrementAndGet();
+    }
+
+    /**
+     * Invoked upon completion (success or failure) of the given operation
+     * @param currentTime elapsed time of the operation
+     */
+    public void after(long currentTime) {
+        current.decrementAndGet();
+        time.inc(currentTime);
+    }
+
+    /**
+     * Invoked upon failure of the operation.
+     */
+    public void failed() {
+        failed.inc();
+    }
+
+    public void add(OperationMetrics other) {
+        // Don't try copying over current, since in-flight requests will be linked to the existing metrics instance.
+        failed.inc(other.failed.count());
+        time.add(other.time);
+    }
+
+    /**
+     * @return an immutable snapshot of the current metric values.
+     */
+    public OperationStats createStats() {
+        return new OperationStats(time.count(), time.sum(), current.get(), failed.count());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/metrics/OperationStats.java b/server/src/main/java/org/opensearch/common/metrics/OperationStats.java
new file mode 100644
index 0000000000000..b2135a54716a9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/metrics/OperationStats.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.metrics;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * An immutable representation of a {@link OperationMetrics}
+ */
+public class OperationStats implements Writeable, ToXContentFragment {
+    private final long count;
+    private final long totalTimeInMillis;
+    private final long current;
+    private final long failedCount;
+
+    public OperationStats(long count, long totalTimeInMillis, long current, long failedCount) {
+        this.count = count;
+        this.totalTimeInMillis = totalTimeInMillis;
+        this.current = current;
+        this.failedCount = failedCount;
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public OperationStats(StreamInput in) throws IOException {
+        count = in.readVLong();
+        totalTimeInMillis = in.readVLong();
+        current = in.readVLong();
+        failedCount = in.readVLong();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(count);
+        out.writeVLong(totalTimeInMillis);
+        out.writeVLong(current);
+        out.writeVLong(failedCount);
+    }
+
+    /**
+     * @return The total number of executed operations.
+     */
+    public long getCount() {
+        return count;
+    }
+
+    /**
+     * @return The total time spent of in millis.
+     */
+    public long getTotalTimeInMillis() {
+        return totalTimeInMillis;
+    }
+
+    /**
+     * @return The total number of operations currently executing.
+     */
+    public long getCurrent() {
+        return current;
+    }
+
+    /**
+     * @return The total number of operations that have failed.
+     */
+    public long getFailedCount() {
+        return failedCount;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.field("count", count)
+            .humanReadableField("time_in_millis", "time", new TimeValue(totalTimeInMillis, TimeUnit.MILLISECONDS))
+            .field("current", current)
+            .field("failed", failedCount);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        OperationStats that = (OperationStats) o;
+        return Objects.equals(count, that.count)
+            && Objects.equals(totalTimeInMillis, that.totalTimeInMillis)
+            && Objects.equals(failedCount, that.failedCount)
+            && Objects.equals(current, that.current);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(count, totalTimeInMillis, failedCount, current);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/metrics/package-info.java b/server/src/main/java/org/opensearch/common/metrics/package-info.java
new file mode 100644
index 0000000000000..58d66e44ef07d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/metrics/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base metrics package. */
+package org.opensearch.common.metrics;
diff --git a/server/src/main/java/org/opensearch/common/network/CloseableChannel.java b/server/src/main/java/org/opensearch/common/network/CloseableChannel.java
index 054a5fac838e9..cc00bf5d1ba65 100644
--- a/server/src/main/java/org/opensearch/common/network/CloseableChannel.java
+++ b/server/src/main/java/org/opensearch/common/network/CloseableChannel.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.common.network;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -44,6 +44,11 @@
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
+/**
+ * Channel that can be closed
+ *
+ * @opensearch.internal
+ */
 public interface CloseableChannel extends Closeable {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/network/IfConfig.java b/server/src/main/java/org/opensearch/common/network/IfConfig.java
index 6c4e14aa29700..9e2ef0263f6ed 100644
--- a/server/src/main/java/org/opensearch/common/network/IfConfig.java
+++ b/server/src/main/java/org/opensearch/common/network/IfConfig.java
@@ -46,6 +46,8 @@
 
 /**
  * Simple class to log {@code ifconfig}-style output at DEBUG logging.
+ *
+ * @opensearch.internal
  */
 public final class IfConfig {
 
diff --git a/server/src/main/java/org/opensearch/common/network/NetworkModule.java b/server/src/main/java/org/opensearch/common/network/NetworkModule.java
index 0b517b8bda97a..0734659d8ee72 100644
--- a/server/src/main/java/org/opensearch/common/network/NetworkModule.java
+++ b/server/src/main/java/org/opensearch/common/network/NetworkModule.java
@@ -40,23 +40,24 @@
 import org.opensearch.cluster.routing.allocation.command.CancelAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.index.shard.PrimaryReplicaSyncer.ResyncTask;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.tasks.RawTaskStatus;
 import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportInterceptor;
@@ -74,6 +75,8 @@
 
 /**
  * A module to handle registering and binding all network related classes.
+ *
+ * @opensearch.internal
  */
 public final class NetworkModule {
 
@@ -145,7 +148,8 @@ public NetworkModule(
         NamedXContentRegistry xContentRegistry,
         NetworkService networkService,
         HttpServerTransport.Dispatcher dispatcher,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         this.settings = settings;
         for (NetworkPlugin plugin : plugins) {
@@ -158,7 +162,8 @@ public NetworkModule(
                 xContentRegistry,
                 networkService,
                 dispatcher,
-                clusterSettings
+                clusterSettings,
+                tracer
             );
             for (Map.Entry<String, Supplier<HttpServerTransport>> entry : httpTransportFactory.entrySet()) {
                 registerHttpTransport(entry.getKey(), entry.getValue());
@@ -169,7 +174,8 @@ public NetworkModule(
                 pageCacheRecycler,
                 circuitBreakerService,
                 namedWriteableRegistry,
-                networkService
+                networkService,
+                tracer
             );
             for (Map.Entry<String, Supplier<Transport>> entry : transportFactory.entrySet()) {
                 registerTransport(entry.getKey(), entry.getValue());
diff --git a/server/src/main/java/org/opensearch/common/network/NetworkService.java b/server/src/main/java/org/opensearch/common/network/NetworkService.java
index b5cad48643b95..4721221879430 100644
--- a/server/src/main/java/org/opensearch/common/network/NetworkService.java
+++ b/server/src/main/java/org/opensearch/common/network/NetworkService.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -48,6 +48,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
+/**
+ * Core network service.
+ *
+ * @opensearch.internal
+ */
 public final class NetworkService {
 
     /** By default, we bind to loopback interfaces */
@@ -108,6 +113,8 @@ public final class NetworkService {
     /**
      * A custom name resolver can support custom lookup keys (my_net_key:ipv4) and also change
      * the default inet address used in case no settings is provided.
+     *
+     * @opensearch.internal
      */
     public interface CustomNameResolver {
         /**
diff --git a/server/src/main/java/org/opensearch/common/network/NetworkUtils.java b/server/src/main/java/org/opensearch/common/network/NetworkUtils.java
index 13e4e5d2434c1..8660b876fa187 100644
--- a/server/src/main/java/org/opensearch/common/network/NetworkUtils.java
+++ b/server/src/main/java/org/opensearch/common/network/NetworkUtils.java
@@ -52,6 +52,8 @@
 /**
  * Utilities for network interfaces / addresses binding and publishing.
  * Its only intended for that purpose, not general purpose usage!!!!
+ *
+ * @opensearch.internal
  */
 public abstract class NetworkUtils {
 
diff --git a/server/src/main/java/org/opensearch/common/network/package-info.java b/server/src/main/java/org/opensearch/common/network/package-info.java
new file mode 100644
index 0000000000000..250423e4fb486
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/network/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base networking support classes package. */
+package org.opensearch.common.network;
diff --git a/server/src/main/java/org/opensearch/common/package-info.java b/server/src/main/java/org/opensearch/common/package-info.java
new file mode 100644
index 0000000000000..09e988590c22d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base package for common classes used across the OpenSearch server codebase. */
+package org.opensearch.common;
diff --git a/server/src/main/java/org/opensearch/common/path/PathTrie.java b/server/src/main/java/org/opensearch/common/path/PathTrie.java
index 4f28b19700799..7cb7b46acfafe 100644
--- a/server/src/main/java/org/opensearch/common/path/PathTrie.java
+++ b/server/src/main/java/org/opensearch/common/path/PathTrie.java
@@ -43,6 +43,11 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Path based on a trie structure.
+ *
+ * @opensearch.internal
+ */
 public class PathTrie<T> {
 
     enum TrieMatchingMode {
@@ -72,6 +77,11 @@ enum TrieMatchingMode {
         TrieMatchingMode.WILDCARD_ROOT_NODES_ALLOWED
     );
 
+    /**
+     * Decoder for the path
+     *
+     * @opensearch.internal
+     */
     public interface Decoder {
         String decode(String value);
     }
@@ -88,6 +98,11 @@ public PathTrie(Decoder decoder) {
         root = new TrieNode(SEPARATOR, null, WILDCARD);
     }
 
+    /**
+     * Node for the trie
+     *
+     * @opensearch.internal
+     */
     public class TrieNode {
         private transient String key;
         private transient T value;
diff --git a/server/src/main/java/org/opensearch/common/path/package-info.java b/server/src/main/java/org/opensearch/common/path/package-info.java
new file mode 100644
index 0000000000000..f171fd0ce8281
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/path/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Path utility package. */
+package org.opensearch.common.path;
diff --git a/server/src/main/java/org/opensearch/common/recycler/package-info.java b/server/src/main/java/org/opensearch/common/recycler/package-info.java
new file mode 100644
index 0000000000000..f59d4db545200
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/recycler/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Resource Recycler package. */
+package org.opensearch.common.recycler;
diff --git a/server/src/main/java/org/opensearch/common/regex/Regex.java b/server/src/main/java/org/opensearch/common/regex/Regex.java
index dc42b09848e36..396af77c8a751 100644
--- a/server/src/main/java/org/opensearch/common/regex/Regex.java
+++ b/server/src/main/java/org/opensearch/common/regex/Regex.java
@@ -35,13 +35,18 @@
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.Operations;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 import java.util.regex.Pattern;
 
+/**
+ * Main regex class.
+ *
+ * @opensearch.internal
+ */
 public class Regex {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/regex/package-info.java b/server/src/main/java/org/opensearch/common/regex/package-info.java
new file mode 100644
index 0000000000000..30140269a2726
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/regex/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Regex utility package. */
+package org.opensearch.common.regex;
diff --git a/server/src/main/java/org/opensearch/common/rounding/DateTimeUnit.java b/server/src/main/java/org/opensearch/common/rounding/DateTimeUnit.java
index eb109ac3d9603..47e182b3caf84 100644
--- a/server/src/main/java/org/opensearch/common/rounding/DateTimeUnit.java
+++ b/server/src/main/java/org/opensearch/common/rounding/DateTimeUnit.java
@@ -39,6 +39,11 @@
 
 import java.util.function.Function;
 
+/**
+ * Main date time unit class.
+ *
+ * @opensearch.internal
+ */
 public enum DateTimeUnit {
 
     WEEK_OF_WEEKYEAR((byte) 1, tz -> ISOChronology.getInstance(tz).weekOfWeekyear()),
diff --git a/server/src/main/java/org/opensearch/common/rounding/Rounding.java b/server/src/main/java/org/opensearch/common/rounding/Rounding.java
index 70677a79b125f..857031bc783f4 100644
--- a/server/src/main/java/org/opensearch/common/rounding/Rounding.java
+++ b/server/src/main/java/org/opensearch/common/rounding/Rounding.java
@@ -32,10 +32,10 @@
 package org.opensearch.common.rounding;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.joda.time.DateTimeField;
 import org.joda.time.DateTimeZone;
 import org.joda.time.IllegalInstantException;
@@ -47,6 +47,8 @@
  * A strategy for rounding long values.
  *
  * Use the java based Rounding class where applicable
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public abstract class Rounding implements Writeable {
@@ -81,6 +83,11 @@ public static Builder builder(TimeValue interval) {
         return new Builder(interval);
     }
 
+    /**
+     * Builder for rounding
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final DateTimeUnit unit;
@@ -118,6 +125,11 @@ public Rounding build() {
         }
     }
 
+    /**
+     * Rounding time units
+     *
+     * @opensearch.internal
+     */
     static class TimeUnitRounding extends Rounding {
 
         static final byte ID = 1;
@@ -284,6 +296,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Rounding time intervals
+     *
+     * @opensearch.internal
+     */
     static class TimeIntervalRounding extends Rounding {
 
         static final byte ID = 2;
@@ -409,6 +426,11 @@ public boolean equals(Object obj) {
         }
     }
 
+    /**
+     * Rounding streams
+     *
+     * @opensearch.internal
+     */
     public static class Streams {
 
         public static void write(Rounding rounding, StreamOutput out) throws IOException {
diff --git a/server/src/main/java/org/opensearch/common/rounding/package-info.java b/server/src/main/java/org/opensearch/common/rounding/package-info.java
new file mode 100644
index 0000000000000..5fa3e39c6a786
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/rounding/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base DateTime rounding package. */
+package org.opensearch.common.rounding;
diff --git a/server/src/main/java/org/opensearch/common/settings/AbstractScopedSettings.java b/server/src/main/java/org/opensearch/common/settings/AbstractScopedSettings.java
index e6a8db808e72a..8a19d309975df 100644
--- a/server/src/main/java/org/opensearch/common/settings/AbstractScopedSettings.java
+++ b/server/src/main/java/org/opensearch/common/settings/AbstractScopedSettings.java
@@ -60,6 +60,8 @@
 /**
  * A basic setting service that can be used for per-index and per-cluster settings.
  * This service offers transactional application of updates settings.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractScopedSettings {
 
@@ -119,8 +121,8 @@ protected AbstractScopedSettings(
                 keySettings.putIfAbsent(setting.getKey(), setting);
             }
         }
-        this.complexMatchers = Collections.unmodifiableMap(complexMatchers);
-        this.keySettings = Collections.unmodifiableMap(keySettings);
+        this.complexMatchers = complexMatchers;
+        this.keySettings = keySettings;
     }
 
     protected void validateSettingKey(Setting<?> setting) {
@@ -142,6 +144,23 @@ protected AbstractScopedSettings(Settings nodeSettings, Settings scopeSettings,
         settingUpdaters.addAll(other.settingUpdaters);
     }
 
+    public boolean registerSetting(Setting<?> setting) {
+        validateSettingKey(setting);
+        if (setting.hasComplexMatcher()) {
+            return setting != complexMatchers.putIfAbsent(setting.getKey(), setting);
+        } else {
+            return setting != keySettings.putIfAbsent(setting.getKey(), setting);
+        }
+    }
+
+    public boolean unregisterSetting(Setting<?> setting) {
+        if (setting.hasComplexMatcher()) {
+            return setting != complexMatchers.remove(setting.getKey());
+        } else {
+            return setting != keySettings.remove(setting.getKey());
+        }
+    }
+
     /**
      * Returns <code>true</code> iff the given key is a valid settings key otherwise <code>false</code>
      */
@@ -629,6 +648,8 @@ void validate(
      * Transactional interface to update settings.
      * @see Setting
      * @param <T> the type of the value of the setting
+     *
+     * @opensearch.internal
      */
     public interface SettingUpdater<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/settings/BaseKeyStoreCommand.java b/server/src/main/java/org/opensearch/common/settings/BaseKeyStoreCommand.java
index b52e55e099cb9..6f4648adc5d19 100644
--- a/server/src/main/java/org/opensearch/common/settings/BaseKeyStoreCommand.java
+++ b/server/src/main/java/org/opensearch/common/settings/BaseKeyStoreCommand.java
@@ -38,10 +38,16 @@
 import org.opensearch.cli.KeyStoreAwareCommand;
 import org.opensearch.cli.Terminal;
 import org.opensearch.cli.UserException;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 
 import java.nio.file.Path;
 
+/**
+ * Base settings class for key store commands.
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseKeyStoreCommand extends KeyStoreAwareCommand {
 
     private KeyStoreWrapper keyStore;
diff --git a/server/src/main/java/org/opensearch/common/settings/ChangeKeyStorePasswordCommand.java b/server/src/main/java/org/opensearch/common/settings/ChangeKeyStorePasswordCommand.java
index d66caca68bfeb..db6c9300ae8b7 100644
--- a/server/src/main/java/org/opensearch/common/settings/ChangeKeyStorePasswordCommand.java
+++ b/server/src/main/java/org/opensearch/common/settings/ChangeKeyStorePasswordCommand.java
@@ -36,10 +36,13 @@
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.Terminal;
 import org.opensearch.cli.UserException;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 
 /**
  * A sub-command for the keystore cli which changes the password.
+ *
+ * @opensearch.internal
  */
 class ChangeKeyStorePasswordCommand extends BaseKeyStoreCommand {
 
diff --git a/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java b/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java
index c758b7d2918e7..1f12971fe4771 100644
--- a/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java
+++ b/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java
@@ -32,17 +32,10 @@
 package org.opensearch.common.settings;
 
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.action.main.TransportMainAction;
-import org.opensearch.cluster.routing.allocation.decider.NodeLoadAwareAllocationDecider;
-import org.opensearch.index.IndexModule;
-import org.opensearch.index.IndexSettings;
-import org.opensearch.index.IndexingPressure;
-import org.opensearch.index.ShardIndexingPressureMemoryManager;
-import org.opensearch.index.ShardIndexingPressureSettings;
-import org.opensearch.index.ShardIndexingPressureStore;
-import org.opensearch.watcher.ResourceWatcherService;
 import org.opensearch.action.admin.cluster.configuration.TransportAddVotingConfigExclusionsAction;
 import org.opensearch.action.admin.indices.close.TransportCloseIndexAction;
+import org.opensearch.action.main.TransportMainAction;
+import org.opensearch.action.search.CreatePitController;
 import org.opensearch.action.search.TransportSearchAction;
 import org.opensearch.action.support.AutoCreateIndex;
 import org.opensearch.action.support.DestructiveOperations;
@@ -63,11 +56,12 @@
 import org.opensearch.cluster.coordination.JoinHelper;
 import org.opensearch.cluster.coordination.LagDetector;
 import org.opensearch.cluster.coordination.LeaderChecker;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.coordination.Reconfigurator;
 import org.opensearch.cluster.metadata.IndexGraveyard;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.OperationRouting;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
@@ -77,16 +71,20 @@
 import org.opensearch.cluster.routing.allocation.decider.DiskThresholdDecider;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.FilterAllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.NodeLoadAwareAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.cluster.service.ClusterApplierService;
+import org.opensearch.cluster.service.ClusterManagerService;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ThreadContext;
@@ -100,7 +98,18 @@
 import org.opensearch.gateway.DanglingIndicesState;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.gateway.PersistedClusterStateService;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
 import org.opensearch.http.HttpTransportSettings;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.IndexingPressure;
+import org.opensearch.index.SegmentReplicationPressureService;
+import org.opensearch.index.ShardIndexingPressureMemoryManager;
+import org.opensearch.index.ShardIndexingPressureSettings;
+import org.opensearch.index.ShardIndexingPressureStore;
+import org.opensearch.index.remote.RemoteStorePressureSettings;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.store.remote.filecache.FileCache;
 import org.opensearch.indices.IndexingMemoryController;
 import org.opensearch.indices.IndicesQueryCache;
 import org.opensearch.indices.IndicesRequestCache;
@@ -121,35 +130,51 @@
 import org.opensearch.node.Node;
 import org.opensearch.node.Node.DiscoverySettings;
 import org.opensearch.node.NodeRoleSettings;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.persistent.PersistentTasksClusterService;
 import org.opensearch.persistent.decider.EnableAssignmentDecider;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.script.ScriptService;
+import org.opensearch.search.SearchBootstrapSettings;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.aggregations.MultiBucketConsumerService;
+import org.opensearch.search.backpressure.settings.NodeDuressSettings;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
 import org.opensearch.search.fetch.subphase.highlight.FastVectorHighlighter;
 import org.opensearch.snapshots.InternalSnapshotsInfoService;
 import org.opensearch.snapshots.SnapshotsService;
+import org.opensearch.tasks.TaskCancellationMonitoringSettings;
+import org.opensearch.tasks.TaskManager;
+import org.opensearch.tasks.TaskResourceTrackingService;
+import org.opensearch.tasks.consumer.TopNSearchTasksLogger;
+import org.opensearch.telemetry.TelemetrySettings;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ProxyConnectionStrategy;
 import org.opensearch.transport.RemoteClusterService;
 import org.opensearch.transport.RemoteConnectionStrategy;
 import org.opensearch.transport.SniffConnectionStrategy;
 import org.opensearch.transport.TransportSettings;
+import org.opensearch.watcher.ResourceWatcherService;
 
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
 
 /**
  * Encapsulates all valid cluster level settings.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class ClusterSettings extends AbstractScopedSettings {
 
     public ClusterSettings(final Settings nodeSettings, final Set<Setting<?>> settingsSet) {
@@ -217,9 +242,12 @@ public void apply(Settings value, Settings current, Settings previous) {
             Arrays.asList(
                 AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING,
                 AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING,
+                AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING,
                 BalancedShardsAllocator.INDEX_BALANCE_FACTOR_SETTING,
                 BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING,
+                BalancedShardsAllocator.PREFER_PRIMARY_SHARD_BALANCE,
                 BalancedShardsAllocator.SHARD_MOVE_PRIMARY_FIRST_SETTING,
+                BalancedShardsAllocator.SHARD_MOVEMENT_STRATEGY_SETTING,
                 BalancedShardsAllocator.THRESHOLD_SETTING,
                 BreakerSettings.CIRCUIT_BREAKER_LIMIT_SETTING,
                 BreakerSettings.CIRCUIT_BREAKER_OVERHEAD_SETTING,
@@ -239,13 +267,20 @@ public void apply(Settings value, Settings current, Settings previous) {
                 IndicesQueryCache.INDICES_CACHE_QUERY_SIZE_SETTING,
                 IndicesQueryCache.INDICES_CACHE_QUERY_COUNT_SETTING,
                 IndicesQueryCache.INDICES_QUERIES_CACHE_ALL_SEGMENTS_SETTING,
+                IndicesService.CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING,
+                IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING,
                 IndicesService.INDICES_ID_FIELD_DATA_ENABLED_SETTING,
                 IndicesService.WRITE_DANGLING_INDICES_INFO_SETTING,
+                IndicesService.CLUSTER_REPLICATION_TYPE_SETTING,
                 MappingUpdatedAction.INDICES_MAPPING_DYNAMIC_TIMEOUT_SETTING,
                 MappingUpdatedAction.INDICES_MAX_IN_FLIGHT_UPDATES_SETTING,
                 Metadata.SETTING_READ_ONLY_SETTING,
                 Metadata.SETTING_READ_ONLY_ALLOW_DELETE_SETTING,
+                Metadata.DEFAULT_REPLICA_COUNT_SETTING,
+                Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING,
                 ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_NODE,
+                ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER,
+                ShardLimitValidator.SETTING_CLUSTER_IGNORE_DOT_INDEXES,
                 RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING,
                 RecoverySettings.INDICES_RECOVERY_RETRY_DELAY_STATE_SYNC_SETTING,
                 RecoverySettings.INDICES_RECOVERY_RETRY_DELAY_NETWORK_SETTING,
@@ -254,6 +289,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 RecoverySettings.INDICES_RECOVERY_INTERNAL_LONG_ACTION_TIMEOUT_SETTING,
                 RecoverySettings.INDICES_RECOVERY_MAX_CONCURRENT_FILE_CHUNKS_SETTING,
                 RecoverySettings.INDICES_RECOVERY_MAX_CONCURRENT_OPERATIONS_SETTING,
+                RecoverySettings.INDICES_RECOVERY_MAX_CONCURRENT_REMOTE_STORE_STREAMS_SETTING,
                 ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_PRIMARIES_RECOVERIES_SETTING,
                 ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING,
                 ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_CONCURRENT_INCOMING_RECOVERIES_SETTING,
@@ -264,6 +300,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING,
                 DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_FLOOD_STAGE_WATERMARK_SETTING,
                 DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING,
+                DiskThresholdSettings.CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE,
                 DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_INCLUDE_RELOCATIONS_SETTING,
                 DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_REROUTE_INTERVAL_SETTING,
                 SameShardAllocationDecider.CLUSTER_ROUTING_ALLOCATION_SAME_HOST_SETTING,
@@ -272,8 +309,8 @@ public void apply(Settings value, Settings current, Settings previous) {
                 InternalClusterInfoService.INTERNAL_CLUSTER_INFO_TIMEOUT_SETTING,
                 InternalSnapshotsInfoService.INTERNAL_SNAPSHOT_INFO_MAX_CONCURRENT_FETCHES_SETTING,
                 DestructiveOperations.REQUIRES_NAME_SETTING,
-                NoMasterBlockService.NO_MASTER_BLOCK_SETTING,  // deprecated
-                NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING,
+                NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING,  // deprecated
+                NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING,
                 GatewayService.EXPECTED_DATA_NODES_SETTING,
                 GatewayService.EXPECTED_MASTER_NODES_SETTING,
                 GatewayService.EXPECTED_NODES_SETTING,
@@ -333,12 +370,13 @@ public void apply(Settings value, Settings current, Settings previous) {
                 IndexModule.NODE_STORE_ALLOW_MMAP,
                 ClusterApplierService.CLUSTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
                 ClusterService.USER_DEFINED_METADATA,
-                MasterService.MASTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,  // deprecated
-                MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
+                ClusterManagerService.MASTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,  // deprecated
+                ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
                 SearchService.DEFAULT_SEARCH_TIMEOUT_SETTING,
                 SearchService.DEFAULT_ALLOW_PARTIAL_SEARCH_RESULTS,
                 TransportSearchAction.SHARD_COUNT_LIMIT_SETTING,
                 TransportSearchAction.SEARCH_CANCEL_AFTER_TIME_INTERVAL_SETTING,
+                TransportSearchAction.SEARCH_REQUEST_STATS_ENABLED,
                 RemoteClusterService.REMOTE_CLUSTER_SKIP_UNAVAILABLE,
                 SniffConnectionStrategy.REMOTE_CONNECTIONS_PER_CLUSTER,
                 RemoteClusterService.REMOTE_INITIAL_CONNECTION_TIMEOUT_SETTING,
@@ -422,6 +460,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 NetworkService.TCP_CONNECT_TIMEOUT,
                 IndexSettings.QUERY_STRING_ANALYZE_WILDCARD,
                 IndexSettings.QUERY_STRING_ALLOW_LEADING_WILDCARD,
+                IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY,
                 ScriptService.SCRIPT_GENERAL_CACHE_SIZE_SETTING,
                 ScriptService.SCRIPT_GENERAL_CACHE_EXPIRE_SETTING,
                 ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING,
@@ -466,6 +505,9 @@ public void apply(Settings value, Settings current, Settings previous) {
                 MultiBucketConsumerService.MAX_BUCKET_SETTING,
                 SearchService.LOW_LEVEL_CANCELLATION_SETTING,
                 SearchService.MAX_OPEN_SCROLL_CONTEXT,
+                SearchService.MAX_OPEN_PIT_CONTEXT,
+                SearchService.MAX_PIT_KEEPALIVE_SETTING,
+                CreatePitController.PIT_INIT_KEEP_ALIVE,
                 Node.WRITE_PORTS_FILE_SETTING,
                 Node.NODE_NAME_SETTING,
                 Node.NODE_ATTRIBUTES,
@@ -520,10 +562,15 @@ public void apply(Settings value, Settings current, Settings previous) {
                 Node.BREAKER_TYPE_KEY,
                 OperationRouting.USE_ADAPTIVE_REPLICA_SELECTION_SETTING,
                 OperationRouting.IGNORE_AWARENESS_ATTRIBUTES_SETTING,
+                OperationRouting.WEIGHTED_ROUTING_DEFAULT_WEIGHT,
+                OperationRouting.WEIGHTED_ROUTING_FAILOPEN_ENABLED,
+                OperationRouting.STRICT_WEIGHTED_SHARD_ROUTING_ENABLED,
+                OperationRouting.IGNORE_WEIGHTED_SHARD_ROUTING,
                 IndexGraveyard.SETTING_MAX_TOMBSTONES,
                 PersistentTasksClusterService.CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING,
                 EnableAssignmentDecider.CLUSTER_TASKS_ALLOCATION_ENABLE_SETTING,
                 PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_SETTING,
+                PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_DURING_DECOMMISSION_SETTING,
                 PeerFinder.DISCOVERY_REQUEST_PEERS_TIMEOUT_SETTING,
                 ClusterFormationFailureHelper.DISCOVERY_CLUSTER_FORMATION_WARNING_TIMEOUT_SETTING,
                 ElectionSchedulerFactory.ELECTION_INITIAL_TIMEOUT_SETTING,
@@ -556,6 +603,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_ALLOW_UNASSIGNED_PRIMARIES_SETTING,
+                NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_FLAT_SKEW_SETTING,
                 ShardIndexingPressureSettings.SHARD_INDEXING_PRESSURE_ENABLED,
                 ShardIndexingPressureSettings.SHARD_INDEXING_PRESSURE_ENFORCED,
                 ShardIndexingPressureSettings.REQUEST_SIZE_WINDOW,
@@ -568,11 +616,87 @@ public void apply(Settings value, Settings current, Settings previous) {
                 ShardIndexingPressureMemoryManager.THROUGHPUT_DEGRADATION_LIMITS,
                 ShardIndexingPressureMemoryManager.SUCCESSFUL_REQUEST_ELAPSED_TIMEOUT,
                 ShardIndexingPressureMemoryManager.MAX_OUTSTANDING_REQUESTS,
-                IndexingPressure.MAX_INDEXING_BYTES
+                IndexingPressure.MAX_INDEXING_BYTES,
+                TaskResourceTrackingService.TASK_RESOURCE_TRACKING_ENABLED,
+                TaskManager.TASK_RESOURCE_CONSUMERS_ENABLED,
+                TopNSearchTasksLogger.LOG_TOP_QUERIES_SIZE_SETTING,
+                TopNSearchTasksLogger.LOG_TOP_QUERIES_FREQUENCY_SETTING,
+                ClusterManagerTaskThrottler.THRESHOLD_SETTINGS,
+                ClusterManagerTaskThrottler.BASE_DELAY_SETTINGS,
+                ClusterManagerTaskThrottler.MAX_DELAY_SETTINGS,
+                // Settings related to search backpressure
+                SearchBackpressureSettings.SETTING_MODE,
+
+                NodeDuressSettings.SETTING_NUM_SUCCESSIVE_BREACHES,
+                NodeDuressSettings.SETTING_CPU_THRESHOLD,
+                NodeDuressSettings.SETTING_HEAP_THRESHOLD,
+                SearchTaskSettings.SETTING_CANCELLATION_RATIO,
+                SearchTaskSettings.SETTING_CANCELLATION_RATE,
+                SearchTaskSettings.SETTING_CANCELLATION_BURST,
+                SearchTaskSettings.SETTING_HEAP_PERCENT_THRESHOLD,
+                SearchTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD,
+                SearchTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE,
+                SearchTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD,
+                SearchTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD,
+                SearchTaskSettings.SETTING_TOTAL_HEAP_PERCENT_THRESHOLD,
+                SearchShardTaskSettings.SETTING_CANCELLATION_RATIO,
+                SearchShardTaskSettings.SETTING_CANCELLATION_RATE,
+                SearchShardTaskSettings.SETTING_CANCELLATION_BURST,
+                SearchShardTaskSettings.SETTING_HEAP_PERCENT_THRESHOLD,
+                SearchShardTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD,
+                SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE,
+                SearchShardTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD,
+                SearchShardTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD,
+                SearchShardTaskSettings.SETTING_TOTAL_HEAP_PERCENT_THRESHOLD,
+                SearchBackpressureSettings.SETTING_CANCELLATION_RATIO,  // deprecated
+                SearchBackpressureSettings.SETTING_CANCELLATION_RATE,   // deprecated
+                SearchBackpressureSettings.SETTING_CANCELLATION_BURST,   // deprecated
+                SegmentReplicationPressureService.SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED,
+                SegmentReplicationPressureService.MAX_INDEXING_CHECKPOINTS,
+                SegmentReplicationPressureService.MAX_REPLICATION_TIME_BACKPRESSURE_SETTING,
+                SegmentReplicationPressureService.MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING,
+                SegmentReplicationPressureService.MAX_ALLOWED_STALE_SHARDS,
+
+                // Settings related to Searchable Snapshots
+                Node.NODE_SEARCH_CACHE_SIZE_SETTING,
+                FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING,
+
+                // Settings related to Remote Refresh Segment Pressure
+                RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED,
+                RemoteStorePressureSettings.BYTES_LAG_VARIANCE_FACTOR,
+                RemoteStorePressureSettings.UPLOAD_TIME_LAG_VARIANCE_FACTOR,
+                RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT,
+
+                // Settings related to Remote Store stats
+                RemoteStoreStatsTrackerFactory.MOVING_AVERAGE_WINDOW_SIZE,
+
+                // Related to monitoring of task cancellation
+                TaskCancellationMonitoringSettings.IS_ENABLED_SETTING,
+                TaskCancellationMonitoringSettings.DURATION_MILLIS_SETTING,
+
+                // Remote cluster state settings
+                RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING,
+                RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING,
+                IndicesService.CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING,
+                IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING
             )
         )
     );
 
     public static List<SettingUpgrader<?>> BUILT_IN_SETTING_UPGRADERS = Collections.emptyList();
 
+    /**
+     * Map of feature flag name to feature-flagged cluster settings. Once each feature
+     * is ready for production release, the feature flag can be removed, and the
+     * setting should be moved to {@link #BUILT_IN_CLUSTER_SETTINGS}.
+     */
+    public static final Map<List<String>, List<Setting>> FEATURE_FLAGGED_CLUSTER_SETTINGS = Map.of(
+        List.of(FeatureFlags.CONCURRENT_SEGMENT_SEARCH),
+        List.of(
+            SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING,
+            SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING
+        ),
+        List.of(FeatureFlags.TELEMETRY),
+        List.of(TelemetrySettings.TRACER_ENABLED_SETTING, TelemetrySettings.TRACER_SAMPLER_PROBABILITY)
+    );
 }
diff --git a/server/src/main/java/org/opensearch/common/settings/ConsistentSettingsService.java b/server/src/main/java/org/opensearch/common/settings/ConsistentSettingsService.java
index fbb37651198d4..c098df3971565 100644
--- a/server/src/main/java/org/opensearch/common/settings/ConsistentSettingsService.java
+++ b/server/src/main/java/org/opensearch/common/settings/ConsistentSettingsService.java
@@ -46,6 +46,7 @@
 import javax.crypto.SecretKey;
 import javax.crypto.SecretKeyFactory;
 import javax.crypto.spec.PBEKeySpec;
+
 import java.nio.charset.StandardCharsets;
 import java.security.NoSuchAlgorithmException;
 import java.security.spec.InvalidKeySpecException;
@@ -64,6 +65,8 @@
  * Used to publish secure setting hashes in the cluster state and to validate those hashes against the local values of those same settings.
  * This is colloquially referred to as the secure setting consistency check. It will publish and verify hashes only for the collection
  * of settings passed in the constructor. The settings have to have the {@link Setting.Property#Consistent} property.
+ *
+ * @opensearch.internal
  */
 public final class ConsistentSettingsService {
     private static final Logger logger = LogManager.getLogger(ConsistentSettingsService.class);
@@ -87,7 +90,7 @@ public ConsistentSettingsService(Settings settings, ClusterService clusterServic
 
     /**
      * Returns a {@link LocalNodeMasterListener} that will publish hashes of all the settings passed in the constructor. These hashes are
-     * published by the master node only. Note that this is not designed for {@link SecureSettings} implementations that are mutable.
+     * published by the cluster-manager node only. Note that this is not designed for {@link SecureSettings} implementations that are mutable.
      */
     public LocalNodeMasterListener newHashPublisher() {
         // eagerly compute hashes to be published
@@ -116,12 +119,12 @@ public boolean areAllConsistent() {
                     concreteSecureSetting.getKey()
                 );
             } else if (publishedSaltAndHash == null && localHash != null) {
-                // setting missing on master but present locally
+                // setting missing on cluster-manager but present locally
                 logger.warn(
                     "no published hash for the consistent secure setting [{}] but it exists on the local node",
                     concreteSecureSetting.getKey()
                 );
-                if (state.nodes().isLocalNodeElectedMaster()) {
+                if (state.nodes().isLocalNodeElectedClusterManager()) {
                     throw new IllegalStateException(
                         "Master node cannot validate consistent setting. No published hash for ["
                             + concreteSecureSetting.getKey()
@@ -160,7 +163,7 @@ public boolean areAllConsistent() {
                         concreteSecureSetting.getKey(),
                         computedSaltedHash
                     );
-                    if (state.nodes().isLocalNodeElectedMaster()) {
+                    if (state.nodes().isLocalNodeElectedClusterManager()) {
                         throw new IllegalStateException(
                             "Master node cannot validate consistent setting. The published hash ["
                                 + publishedHash
@@ -283,7 +286,7 @@ public void onFailure(String source, Exception e) {
 
         @Override
         public void offMaster() {
-            logger.trace("I am no longer master, nothing to do");
+            logger.trace("I am no longer cluster-manager, nothing to do");
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/common/settings/FeatureFlagSettings.java b/server/src/main/java/org/opensearch/common/settings/FeatureFlagSettings.java
new file mode 100644
index 0000000000000..90abc0a0765c1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/settings/FeatureFlagSettings.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.settings;
+
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.util.FeatureFlags;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Encapsulates all valid feature flag level settings.
+ *
+ * @opensearch.internal
+ */
+public class FeatureFlagSettings extends AbstractScopedSettings {
+
+    protected FeatureFlagSettings(
+        Settings settings,
+        Set<Setting<?>> settingsSet,
+        Set<SettingUpgrader<?>> settingUpgraders,
+        Property scope
+    ) {
+        super(settings, settingsSet, settingUpgraders, scope);
+    }
+
+    public static final Set<Setting<?>> BUILT_IN_FEATURE_FLAGS = Collections.unmodifiableSet(
+        new HashSet<>(
+            Arrays.asList(
+                FeatureFlags.SEGMENT_REPLICATION_EXPERIMENTAL_SETTING,
+                FeatureFlags.EXTENSIONS_SETTING,
+                FeatureFlags.IDENTITY_SETTING,
+                FeatureFlags.CONCURRENT_SEGMENT_SEARCH_SETTING,
+                FeatureFlags.TELEMETRY_SETTING
+            )
+        )
+    );
+}
diff --git a/server/src/main/java/org/opensearch/common/settings/HasPasswordKeyStoreCommand.java b/server/src/main/java/org/opensearch/common/settings/HasPasswordKeyStoreCommand.java
index dc8993f55fae2..640e616bb2c77 100644
--- a/server/src/main/java/org/opensearch/common/settings/HasPasswordKeyStoreCommand.java
+++ b/server/src/main/java/org/opensearch/common/settings/HasPasswordKeyStoreCommand.java
@@ -40,6 +40,11 @@
 
 import java.nio.file.Path;
 
+/**
+ * KeyStore command that has a password.
+ *
+ * @opensearch.internal
+ */
 public class HasPasswordKeyStoreCommand extends KeyStoreAwareCommand {
 
     static final int NO_PASSWORD_EXIT_CODE = 1;
diff --git a/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java b/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
index 4c7b3fe25296e..83bf8c82ee3dd 100644
--- a/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
+++ b/server/src/main/java/org/opensearch/common/settings/IndexScopedSettings.java
@@ -40,13 +40,16 @@
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.IndexSortConfig;
 import org.opensearch.index.IndexingSlowLog;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.LogByteSizeMergePolicyProvider;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.MergeSchedulerConfig;
 import org.opensearch.index.SearchSlowLog;
+import org.opensearch.index.TieredMergePolicyProvider;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
 import org.opensearch.index.engine.EngineConfig;
 import org.opensearch.index.fielddata.IndexFieldDataService;
@@ -60,6 +63,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
@@ -67,11 +71,15 @@
 /**
  * Encapsulates all valid index level settings.
  * @see Property#IndexScope
+ *
+ * @opensearch.internal
  */
 public final class IndexScopedSettings extends AbstractScopedSettings {
 
     public static final Predicate<String> INDEX_SETTINGS_KEY_PREDICATE = (s) -> s.startsWith(IndexMetadata.INDEX_SETTING_PREFIX);
 
+    public static final Predicate<String> ARCHIVED_SETTINGS_KEY_PREDICATE = (s) -> s.startsWith(ARCHIVED_SETTINGS_PREFIX);
+
     public static final Set<Setting<?>> BUILT_IN_INDEX_SETTINGS = Collections.unmodifiableSet(
         new HashSet<>(
             Arrays.asList(
@@ -97,6 +105,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexMetadata.INDEX_DATA_PATH_SETTING,
                 IndexMetadata.INDEX_FORMAT_SETTING,
                 IndexMetadata.INDEX_HIDDEN_SETTING,
+                IndexMetadata.INDEX_REPLICATION_TYPE_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_DEBUG_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_WARN_SETTING,
                 SearchSlowLog.INDEX_SEARCH_SLOWLOG_THRESHOLD_FETCH_INFO_SETTING,
@@ -113,14 +122,14 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexingSlowLog.INDEX_INDEXING_SLOWLOG_LEVEL_SETTING,
                 IndexingSlowLog.INDEX_INDEXING_SLOWLOG_REFORMAT_SETTING,
                 IndexingSlowLog.INDEX_INDEXING_SLOWLOG_MAX_SOURCE_CHARS_TO_LOG_SETTING,
-                MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING,
-                MergePolicyConfig.INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING,
+                TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING,
+                TieredMergePolicyProvider.INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING,
                 IndexSortConfig.INDEX_SORT_FIELD_SETTING,
                 IndexSortConfig.INDEX_SORT_ORDER_SETTING,
                 IndexSortConfig.INDEX_SORT_MISSING_SETTING,
@@ -146,6 +155,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexSettings.INDEX_CHECK_ON_STARTUP,
                 IndexSettings.MAX_REFRESH_LISTENERS_PER_SHARD,
                 IndexSettings.MAX_SLICES_PER_SCROLL,
+                IndexSettings.MAX_SLICES_PER_PIT,
                 IndexSettings.MAX_REGEX_LENGTH_SETTING,
                 ShardsLimitAllocationDecider.INDEX_TOTAL_SHARDS_PER_NODE_SETTING,
                 IndexSettings.INDEX_GC_DELETES_SETTING,
@@ -163,6 +173,7 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexSettings.INDEX_TRANSLOG_RETENTION_SIZE_SETTING,
                 IndexSettings.INDEX_SEARCH_IDLE_AFTER,
                 IndexSettings.INDEX_SEARCH_THROTTLED,
+                IndexSettings.INDEX_UNREFERENCED_FILE_CLEANUP,
                 IndexFieldDataService.INDEX_FIELDDATA_CACHE_KEY,
                 FieldMapper.IGNORE_MALFORMED_SETTING,
                 FieldMapper.COERCE_SETTING,
@@ -176,17 +187,45 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 BitsetFilterCache.INDEX_LOAD_RANDOM_ACCESS_FILTERS_EAGERLY_SETTING,
                 IndexModule.INDEX_STORE_TYPE_SETTING,
                 IndexModule.INDEX_STORE_PRE_LOAD_SETTING,
+                IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS,
+                IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS,
                 IndexModule.INDEX_RECOVERY_TYPE_SETTING,
                 IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING,
                 FsDirectoryFactory.INDEX_LOCK_FACTOR_SETTING,
                 Store.FORCE_RAM_TERM_DICT,
                 EngineConfig.INDEX_CODEC_SETTING,
+                EngineConfig.INDEX_CODEC_COMPRESSION_LEVEL_SETTING,
                 EngineConfig.INDEX_OPTIMIZE_AUTO_GENERATED_IDS,
                 IndexMetadata.SETTING_WAIT_FOR_ACTIVE_SHARDS,
                 IndexSettings.DEFAULT_PIPELINE,
                 IndexSettings.FINAL_PIPELINE,
                 MetadataIndexStateService.VERIFIED_BEFORE_CLOSE_SETTING,
                 ExistingShardsAllocator.EXISTING_SHARDS_ALLOCATOR_SETTING,
+                IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED,
+                IndexSettings.INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME,
+                IndexSettings.INDEX_MERGE_ON_FLUSH_POLICY,
+                IndexSettings.INDEX_MERGE_POLICY,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MERGE_FACTOR_SETTING,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MIN_MERGE_SETTING,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_SETTING,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_FOR_FORCED_MERGE_SETTING,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGED_DOCS_SETTING,
+                LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING,
+                IndexSettings.DEFAULT_SEARCH_PIPELINE,
+
+                // Settings for Searchable Snapshots
+                IndexSettings.SEARCHABLE_SNAPSHOT_REPOSITORY,
+                IndexSettings.SEARCHABLE_SNAPSHOT_INDEX_ID,
+                IndexSettings.SEARCHABLE_SNAPSHOT_ID_NAME,
+                IndexSettings.SEARCHABLE_SNAPSHOT_ID_UUID,
+
+                // Settings for remote translog
+                IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING,
+
+                // Settings for remote store enablement
+                IndexMetadata.INDEX_REMOTE_STORE_ENABLED_SETTING,
+                IndexMetadata.INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING,
+                IndexMetadata.INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING,
 
                 // validate that built-in similarities don't get redefined
                 Setting.groupSetting("index.similarity.", (s) -> {
@@ -205,6 +244,16 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
         )
     );
 
+    /**
+     * Map of feature flag name to feature-flagged index setting. Once each feature
+     * is ready for production release, the feature flag can be removed, and the
+     * setting should be moved to {@link #BUILT_IN_INDEX_SETTINGS}.
+     */
+    public static final Map<String, List<Setting>> FEATURE_FLAGGED_INDEX_SETTINGS = Map.of(
+        FeatureFlags.CONCURRENT_SEGMENT_SEARCH,
+        List.of(IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING)
+    );
+
     public static final IndexScopedSettings DEFAULT_SCOPED_SETTINGS = new IndexScopedSettings(Settings.EMPTY, BUILT_IN_INDEX_SETTINGS);
 
     public IndexScopedSettings(Settings settings, Set<Setting<?>> settingsSet) {
@@ -235,7 +284,7 @@ public boolean isPrivateSetting(String key) {
             case IndexMetadata.SETTING_HISTORY_UUID:
             case IndexMetadata.SETTING_VERSION_UPGRADED:
             case IndexMetadata.SETTING_INDEX_PROVIDED_NAME:
-            case MergePolicyConfig.INDEX_MERGE_ENABLED:
+            case MergePolicyProvider.INDEX_MERGE_ENABLED:
                 // we keep the shrink settings for BWC - this can be removed in 8.0
                 // we can't remove in 7 since this setting might be baked into an index coming in via a full cluster restart from 6.0
             case "index.shrink.source.uuid":
diff --git a/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java b/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
index 900eda6975526..f25dd872fc703 100644
--- a/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
+++ b/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
@@ -40,11 +40,12 @@
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.NIOFSDirectory;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.UserException;
 import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.hash.MessageDigests;
+import org.opensearch.core.common.settings.SecureString;
 
 import javax.crypto.AEADBadTagException;
 import javax.crypto.Cipher;
@@ -55,6 +56,7 @@
 import javax.crypto.spec.GCMParameterSpec;
 import javax.crypto.spec.PBEKeySpec;
 import javax.crypto.spec.SecretKeySpec;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
@@ -91,6 +93,8 @@
  * {@link #decrypt(char[])} with the keystore password, or an empty char array if
  * {@link #hasPassword()} is {@code false}.  Loading and decrypting should happen
  * in a single thread. Once decrypted, settings may be read in multiple threads.
+ *
+ * @opensearch.internal
  */
 public class KeyStoreWrapper implements SecureSettings {
 
@@ -100,7 +104,11 @@ private enum EntryType {
         FILE
     }
 
-    /** An entry in the keystore. The bytes are opaque and interpreted based on the entry type. */
+    /**
+     * An entry in the keystore. The bytes are opaque and interpreted based on the entry type.
+     *
+     * @opensearch.internal
+     */
     private static class Entry {
         final byte[] bytes;
         final byte[] sha256Digest;
diff --git a/server/src/main/java/org/opensearch/common/settings/NoClassSettingsException.java b/server/src/main/java/org/opensearch/common/settings/NoClassSettingsException.java
index 5600900c1f02b..12d7df66deddf 100644
--- a/server/src/main/java/org/opensearch/common/settings/NoClassSettingsException.java
+++ b/server/src/main/java/org/opensearch/common/settings/NoClassSettingsException.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.common.settings;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
@@ -40,7 +40,7 @@
  * A specific type of {@link SettingsException} indicating failure to load a class
  * based on a settings value.
  *
- *
+ * @opensearch.internal
  */
 public class NoClassSettingsException extends SettingsException {
 
diff --git a/server/src/main/java/org/opensearch/common/settings/PropertyPlaceholder.java b/server/src/main/java/org/opensearch/common/settings/PropertyPlaceholder.java
index 557710b7b69f1..655ffc461cd91 100644
--- a/server/src/main/java/org/opensearch/common/settings/PropertyPlaceholder.java
+++ b/server/src/main/java/org/opensearch/common/settings/PropertyPlaceholder.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.common.settings;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.util.HashSet;
 import java.util.Objects;
@@ -46,6 +46,8 @@
  * <p>
  * Values for substitution can be supplied using a {@link Properties} instance or using a
  * {@link PlaceholderResolver}.
+ *
+ * @opensearch.internal
  */
 class PropertyPlaceholder {
 
@@ -160,6 +162,8 @@ private int findPlaceholderEndIndex(CharSequence buf, int startIndex) {
      * Strategy interface used to resolve replacement values for placeholders contained in Strings.
      *
      * @see PropertyPlaceholder
+     *
+     * @opensearch.internal
      */
     interface PlaceholderResolver {
 
diff --git a/server/src/main/java/org/opensearch/common/settings/SecureSetting.java b/server/src/main/java/org/opensearch/common/settings/SecureSetting.java
index fa828746ab36d..f2ccc01a4c7e6 100644
--- a/server/src/main/java/org/opensearch/common/settings/SecureSetting.java
+++ b/server/src/main/java/org/opensearch/common/settings/SecureSetting.java
@@ -32,8 +32,11 @@
 
 package org.opensearch.common.settings;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.common.settings.SecureString;
 
 import java.io.InputStream;
 import java.security.GeneralSecurityException;
@@ -44,6 +47,8 @@
  * A secure setting.
  *
  * This class allows access to settings from the OpenSearch keystore.
+ *
+ * @opensearch.internal
  */
 public abstract class SecureSetting<T> extends Setting<T> {
 
@@ -159,7 +164,17 @@ public static Setting<SecureString> secureString(String name, Setting<SecureStri
      * @see #secureString(String, Setting, Property...)
      */
     public static Setting<SecureString> insecureString(String name) {
-        return new InsecureStringSetting(name);
+        return insecureString(name, null, false);
+    }
+
+    /**
+     * A setting which contains a sensitive string, but usage is logged when found outside secure settings, regardless
+     * of the opensearch.allow_insecure_settings value. Typically. this is used when migrating old legacy settings
+     * to secure variants while preserving existing functionality.
+     * @see #insecureString(String)
+     */
+    public static Setting<SecureString> insecureString(String name, String secureName, boolean allowWithWarning) {
+        return new InsecureStringSetting(name, secureName, allowWithWarning);
     }
 
     /**
@@ -171,6 +186,11 @@ public static Setting<InputStream> secureFile(String name, Setting<InputStream>
         return new SecureFileSetting(name, fallback, properties);
     }
 
+    /**
+     * Setting for a secure string
+     *
+     * @opensearch.internal
+     */
     private static class SecureStringSetting extends SecureSetting<SecureString> {
         private final Setting<SecureString> fallback;
 
@@ -193,25 +213,53 @@ SecureString getFallback(Settings settings) {
         }
     }
 
+    /**
+     * An insecure string setting
+     *
+     * @opensearch.internal
+     */
     private static class InsecureStringSetting extends Setting<SecureString> {
+        private static final Logger LOG = LogManager.getLogger(InsecureStringSetting.class);
         private final String name;
+        private final String secureName;
+        private final boolean allowWithWarning;
+
+        private boolean warningLogged;
 
-        private InsecureStringSetting(String name) {
+        private InsecureStringSetting(String name, String secureName, boolean allowWithWarning) {
             super(name, "", SecureString::new, Property.Deprecated, Property.Filtered, Property.NodeScope);
             this.name = name;
+            this.secureName = secureName;
+            this.allowWithWarning = allowWithWarning;
         }
 
         @Override
         public SecureString get(Settings settings) {
-            if (ALLOW_INSECURE_SETTINGS == false && exists(settings)) {
-                throw new IllegalArgumentException(
-                    "Setting [" + name + "] is insecure, " + "but property [allow_insecure_settings] is not set"
-                );
+            if (exists(settings)) {
+                logUsage();
+
+                if (ALLOW_INSECURE_SETTINGS == false && this.allowWithWarning == false) {
+                    throw new IllegalArgumentException(
+                        "Setting [" + name + "] is insecure, " + "but property [allow_insecure_settings] is not set"
+                    );
+                }
             }
             return super.get(settings);
         }
+
+        private synchronized void logUsage() {
+            if (!this.warningLogged) {
+                LOG.warn("Setting [{}] is insecure, but a secure variant [{}] is advised to be used instead", this.name, this.secureName);
+                this.warningLogged = true;
+            }
+        }
     }
 
+    /**
+     * A secure file setting
+     *
+     * @opensearch.internal
+     */
     private static class SecureFileSetting extends SecureSetting<InputStream> {
         private final Setting<InputStream> fallback;
 
diff --git a/server/src/main/java/org/opensearch/common/settings/SecureSettings.java b/server/src/main/java/org/opensearch/common/settings/SecureSettings.java
index 05ed83573bb6c..3732478243dab 100644
--- a/server/src/main/java/org/opensearch/common/settings/SecureSettings.java
+++ b/server/src/main/java/org/opensearch/common/settings/SecureSettings.java
@@ -32,6 +32,9 @@
 
 package org.opensearch.common.settings;
 
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.settings.SecureString;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
@@ -40,7 +43,10 @@
 
 /**
  * An accessor for settings which are securely stored. See {@link SecureSetting}.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface SecureSettings extends Closeable {
 
     /** Returns true iff the settings are loaded and retrievable. */
diff --git a/server/src/main/java/org/opensearch/common/settings/Setting.java b/server/src/main/java/org/opensearch/common/settings/Setting.java
index 8618687218987..0e96edff0681c 100644
--- a/server/src/main/java/org/opensearch/common/settings/Setting.java
+++ b/server/src/main/java/org/opensearch/common/settings/Setting.java
@@ -38,19 +38,24 @@
 import org.opensearch.Version;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.MemorySizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -97,9 +102,18 @@
  *     new Setting<>("my.color.setting", Color.RED.toString(), Color::valueOf, Setting.Property.NodeScope);
  * }
  * </pre>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class Setting<T> implements ToXContentObject {
 
+    /**
+     * Property of the setting
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public enum Property {
         /**
          * should be filtered in some api (mask password/credentials)
@@ -152,15 +166,20 @@ public enum Property {
         /**
          * Indicates an index-level setting that is privately managed. Such a setting can not even be set on index creation.
          */
-        PrivateIndex
+        PrivateIndex,
+
+        /**
+         * Extension scope
+         */
+        ExtensionScope
     }
 
     private final Key key;
     protected final Function<Settings, String> defaultValue;
     @Nullable
     protected final Setting<T> fallbackSetting;
-    private final Function<String, T> parser;
-    private final Validator<T> validator;
+    protected final Function<String, T> parser;
+    protected final Validator<T> validator;
     private final EnumSet<Property> properties;
 
     private static final EnumSet<Property> EMPTY_PROPERTIES = EnumSet.noneOf(Property.class);
@@ -587,7 +606,7 @@ public final XContentBuilder toXContent(XContentBuilder builder, Params params)
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     /**
@@ -618,7 +637,10 @@ public Setting<T> getConcreteSetting(String key) {
     /**
      * Allows a setting to declare a dependency on another setting being set. Optionally, a setting can validate the value of the dependent
      * setting.
+     *
+     * @opensearch.api
      */
+    @PublicApi(since = "1.0.0")
     public interface SettingDependency {
 
         /**
@@ -765,7 +787,10 @@ public String toString() {
 
     /**
      * Allows an affix setting to declare a dependency on another affix setting.
+     *
+     * @opensearch.api
      */
+    @PublicApi(since = "1.0.0")
     public interface AffixSettingDependency extends SettingDependency {
 
         @Override
@@ -773,6 +798,12 @@ public interface AffixSettingDependency extends SettingDependency {
 
     }
 
+    /**
+     * An affix setting
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public static class AffixSetting<T> extends Setting<T> {
         private final AffixKey key;
         private final BiFunction<String, String, Setting<T>> delegateFactory;
@@ -1000,8 +1031,11 @@ public Map<String, T> getAsMap(Settings settings) {
      * {@link #settings()}} to their values. All these values come from the same {@link Settings} instance.
      *
      * @param <T> the type of the {@link Setting}
+     *
+     * @opensearch.api
      */
     @FunctionalInterface
+    @PublicApi(since = "1.0.0")
     public interface Validator<T> {
 
         /**
@@ -1044,6 +1078,11 @@ default Iterator<Setting<?>> settings() {
 
     }
 
+    /**
+     * A group setting
+     *
+     * @opensearch.internal
+     */
     private static class GroupSetting extends Setting<Settings> {
         private final String key;
         private final Consumer<Settings> validator;
@@ -1073,7 +1112,7 @@ public String innerGetRaw(final Settings settings) {
                 builder.startObject();
                 subSettings.toXContent(builder, EMPTY_PARAMS);
                 builder.endObject();
-                return Strings.toString(builder);
+                return builder.toString();
             } catch (IOException e) {
                 throw new RuntimeException(e);
             }
@@ -1224,6 +1263,55 @@ private static boolean isFiltered(Property[] properties) {
         return properties != null && Arrays.asList(properties).contains(Property.Filtered);
     }
 
+    /**
+     * A writeable validator able to check the value of string type custom setting by using regular expression
+     */
+    public static class RegexValidator implements Writeable, Validator<String> {
+        private Pattern pattern;
+
+        private boolean isMatching;
+
+        /**
+         * @param regex A regular expression containing the only valid input for this setting.
+         */
+        public RegexValidator(String regex) {
+            this(regex, true);
+        }
+
+        /**
+         * @param regex constructs a validator based on a regular expression.
+         * @param isMatching If true, the setting must match the given regex. If false, the setting must not match the given regex.
+         */
+        public RegexValidator(String regex, boolean isMatching) {
+            this.pattern = Pattern.compile(regex);
+            this.isMatching = isMatching;
+        }
+
+        public RegexValidator(StreamInput in) throws IOException {
+            this.pattern = Pattern.compile(in.readString());
+            this.isMatching = in.readBoolean();
+        }
+
+        Pattern getPattern() {
+            return pattern;
+        }
+
+        @Override
+        public void validate(String value) {
+            if (isMatching && !pattern.matcher(value).find()) {
+                throw new IllegalArgumentException("Setting [" + value + "] does not match regex [" + pattern.pattern() + "]");
+            } else if (!isMatching && pattern.matcher(value).find()) {
+                throw new IllegalArgumentException("Setting [" + value + "] must match regex [" + pattern.pattern() + "]");
+            }
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(pattern.pattern());
+            out.writeBoolean(isMatching);
+        }
+    }
+
     // Float
 
     private static float parseFloat(String s, float minValue, float maxValue, String key, boolean isFiltered) {
@@ -1264,12 +1352,80 @@ public static Setting<Float> floatSetting(
         return new Setting<>(
             key,
             Float.toString(defaultValue),
-            (s) -> parseFloat(s, minValue, maxValue, key, isFiltered(properties)),
+            new FloatParser(minValue, maxValue, key, isFiltered(properties)),
             validator,
             properties
         );
     }
 
+    /**
+     * A writeable parser for float
+     *
+     */
+    public static class FloatParser implements Function<String, Float>, Writeable {
+        private float minValue;
+        private float maxValue;
+        private String key;
+        private boolean isFiltered;
+
+        public FloatParser(float minValue, float maxValue, String key, boolean isFiltered) {
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.key = key;
+            this.isFiltered = isFiltered;
+        }
+
+        public FloatParser(StreamInput in) throws IOException {
+            minValue = in.readFloat();
+            maxValue = in.readFloat();
+            key = in.readString();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeFloat(minValue);
+            out.writeFloat(maxValue);
+            out.writeString(key);
+            out.writeBoolean(isFiltered);
+        }
+
+        public float getMin() {
+            return minValue;
+        }
+
+        public float getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public Float apply(String s) {
+            return parseFloat(s, minValue, maxValue, key, isFiltered);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            FloatParser that = (FloatParser) obj;
+            return Objects.equals(key, that.key)
+                && Objects.equals(minValue, that.minValue)
+                && Objects.equals(maxValue, that.maxValue)
+                && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(minValue, maxValue, key, isFiltered);
+        }
+    }
+
     // Setting<Float> with fallback
 
     public static Setting<Float> floatSetting(String key, Setting<Float> fallbackSetting, Property... properties) {
@@ -1366,12 +1522,80 @@ public static Setting<Integer> intSetting(
         return new Setting<>(
             key,
             Integer.toString(defaultValue),
-            (s) -> parseInt(s, minValue, maxValue, key, isFiltered(properties)),
+            new IntegerParser(minValue, maxValue, key, isFiltered(properties)),
             validator,
             properties
         );
     }
 
+    /**
+     * A writeable parser for integer
+     *
+     */
+    public static class IntegerParser implements Function<String, Integer>, Writeable {
+        private String key;
+        private int minValue;
+        private int maxValue;
+        private boolean isFiltered;
+
+        public IntegerParser(int minValue, int maxValue, String key, boolean isFiltered) {
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.key = key;
+            this.isFiltered = isFiltered;
+        }
+
+        public IntegerParser(StreamInput in) throws IOException {
+            minValue = in.readInt();
+            maxValue = in.readInt();
+            key = in.readString();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeInt(minValue);
+            out.writeInt(maxValue);
+            out.writeString(key);
+            out.writeBoolean(isFiltered);
+        }
+
+        public int getMin() {
+            return minValue;
+        }
+
+        public int getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public Integer apply(String s) {
+            return parseInt(s, minValue, maxValue, key, isFiltered);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            IntegerParser that = (IntegerParser) obj;
+            return Objects.equals(key, that.key)
+                && Objects.equals(minValue, that.minValue)
+                && Objects.equals(maxValue, that.maxValue)
+                && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(minValue, maxValue, key, isFiltered);
+        }
+    }
+
     // Setting<Integer> with fallback
 
     public static Setting<Integer> intSetting(String key, Setting<Integer> fallbackSetting, Property... properties) {
@@ -1460,12 +1684,80 @@ public static Setting<Long> longSetting(
         return new Setting<>(
             key,
             Long.toString(defaultValue),
-            (s) -> parseLong(s, minValue, maxValue, key, isFiltered(properties)),
+            new LongParser(minValue, maxValue, key, isFiltered(properties)),
             validator,
             properties
         );
     }
 
+    /**
+     * A writeable parser for long
+     *
+     */
+    public static class LongParser implements Function<String, Long>, Writeable {
+        private String key;
+        private long minValue;
+        private long maxValue;
+        private boolean isFiltered;
+
+        public LongParser(long minValue, long maxValue, String key, boolean isFiltered) {
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.key = key;
+            this.isFiltered = isFiltered;
+        }
+
+        public LongParser(StreamInput in) throws IOException {
+            minValue = in.readLong();
+            maxValue = in.readLong();
+            key = in.readString();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeLong(minValue);
+            out.writeLong(maxValue);
+            out.writeString(key);
+            out.writeBoolean(isFiltered);
+        }
+
+        public long getMin() {
+            return minValue;
+        }
+
+        public long getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public Long apply(String s) {
+            return parseLong(s, minValue, maxValue, key, isFiltered);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            LongParser that = (LongParser) obj;
+            return Objects.equals(key, that.key)
+                && Objects.equals(minValue, that.minValue)
+                && Objects.equals(maxValue, that.maxValue)
+                && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(minValue, maxValue, key, isFiltered);
+        }
+    }
+
     // Setting<Long> with fallback
 
     public static Setting<Long> longSetting(String key, Setting<Long> fallbackSetting, Property... properties) {
@@ -1554,12 +1846,80 @@ public static Setting<Double> doubleSetting(
         return new Setting<>(
             key,
             Double.toString(defaultValue),
-            (s) -> parseDouble(s, minValue, maxValue, key, isFiltered(properties)),
+            new DoubleParser(minValue, maxValue, key, isFiltered(properties)),
             validator,
             properties
         );
     }
 
+    /**
+     * A writeable parser for double
+     *
+     */
+    public static class DoubleParser implements Function<String, Double>, Writeable {
+        private double minValue;
+        private double maxValue;
+        private String key;
+        private boolean isFiltered;
+
+        public DoubleParser(double minValue, double maxValue, String key, boolean isFiltered) {
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.key = key;
+            this.isFiltered = isFiltered;
+        }
+
+        public DoubleParser(StreamInput in) throws IOException {
+            minValue = in.readDouble();
+            maxValue = in.readDouble();
+            key = in.readString();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeDouble(minValue);
+            out.writeDouble(maxValue);
+            out.writeString(key);
+            out.writeBoolean(isFiltered);
+        }
+
+        public double getMin() {
+            return minValue;
+        }
+
+        public double getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public Double apply(String s) {
+            return parseDouble(s, minValue, maxValue, key, isFiltered);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            DoubleParser that = (DoubleParser) obj;
+            return Objects.equals(key, that.key)
+                && Objects.equals(minValue, that.minValue)
+                && Objects.equals(maxValue, that.maxValue)
+                && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(minValue, maxValue, key, isFiltered);
+        }
+    }
+
     // Setting<Double> with fallback
 
     public static Setting<Double> doubleSetting(String key, Setting<Double> fallbackSetting, Property... properties) {
@@ -1695,15 +2055,15 @@ static boolean parseBoolean(String b, String key, boolean isFiltered) {
     }
 
     public static Setting<ByteSizeValue> byteSizeSetting(String key, ByteSizeValue value, Property... properties) {
-        return byteSizeSetting(key, (s) -> value.toString(), properties);
+        return byteSizeSetting(key, (s) -> value.getBytes() + ByteSizeUnit.BYTES.getSuffix(), properties);
     }
 
     public static Setting<ByteSizeValue> byteSizeSetting(String key, Setting<ByteSizeValue> fallbackSetting, Property... properties) {
-        return new Setting<>(key, fallbackSetting, (s) -> ByteSizeValue.parseBytesSizeValue(s, key), properties);
+        return new Setting<>(key, fallbackSetting, new ByteSizeValueParser(key), properties);
     }
 
     public static Setting<ByteSizeValue> byteSizeSetting(String key, Function<Settings, String> defaultValue, Property... properties) {
-        return new Setting<>(key, defaultValue, (s) -> ByteSizeValue.parseBytesSizeValue(s, key), properties);
+        return new Setting<>(key, defaultValue, new ByteSizeValueParser(key), properties);
     }
 
     public static Setting<ByteSizeValue> byteSizeSetting(
@@ -1723,7 +2083,68 @@ public static Setting<ByteSizeValue> byteSizeSetting(
         ByteSizeValue maxValue,
         Property... properties
     ) {
-        return new Setting<>(key, defaultValue, (s) -> parseByteSize(s, minValue, maxValue, key), properties);
+        return new Setting<>(key, defaultValue, new ByteSizeValueParser(minValue, maxValue, key), properties);
+    }
+
+    /**
+     * A writeable parser for bytesizevalue
+     *
+     */
+    public static class ByteSizeValueParser implements Function<String, ByteSizeValue>, Writeable {
+        private ByteSizeValue minValue;
+        private ByteSizeValue maxValue;
+        private String key;
+
+        public ByteSizeValueParser(ByteSizeValue minValue, ByteSizeValue maxValue, String key) {
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.key = key;
+        }
+
+        public ByteSizeValueParser(String key) {
+            this(new ByteSizeValue(-1), new ByteSizeValue(Long.MAX_VALUE), key);
+        }
+
+        public ByteSizeValueParser(StreamInput in) throws IOException {
+            minValue = new ByteSizeValue(in);
+            maxValue = new ByteSizeValue(in);
+            key = in.readString();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            ((ByteSizeValue) minValue).writeTo(out);
+            ((ByteSizeValue) maxValue).writeTo(out);
+            out.writeString(key);
+        }
+
+        public ByteSizeValue getMin() {
+            return minValue;
+        }
+
+        public ByteSizeValue getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        @Override
+        public ByteSizeValue apply(String s) {
+            return parseByteSize(s, minValue, maxValue, key);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            ByteSizeValueParser that = (ByteSizeValueParser) obj;
+            return Objects.equals(key, that.key) && Objects.equals(minValue, that.minValue) && Objects.equals(maxValue, that.maxValue);
+        }
+
+        public int hashCode() {
+            return Objects.hash(key, minValue, maxValue);
+        }
     }
 
     public static ByteSizeValue parseByteSize(String s, ByteSizeValue minValue, ByteSizeValue maxValue, String key) {
@@ -1776,7 +2197,7 @@ public static Setting<ByteSizeValue> memorySizeSetting(String key, ByteSizeValue
      * @return the setting object
      */
     public static Setting<ByteSizeValue> memorySizeSetting(String key, Function<Settings, String> defaultValue, Property... properties) {
-        return new Setting<>(key, defaultValue, (s) -> MemorySizeValue.parseBytesSizeValueOrHeapRatio(s, key), properties);
+        return new Setting<>(key, defaultValue, new MemorySizeValueParser(key), properties);
     }
 
     /**
@@ -1790,7 +2211,47 @@ public static Setting<ByteSizeValue> memorySizeSetting(String key, Function<Sett
      * @return the setting object
      */
     public static Setting<ByteSizeValue> memorySizeSetting(String key, String defaultPercentage, Property... properties) {
-        return new Setting<>(key, (s) -> defaultPercentage, (s) -> MemorySizeValue.parseBytesSizeValueOrHeapRatio(s, key), properties);
+        return new Setting<>(key, (s) -> defaultPercentage, new MemorySizeValueParser(key), properties);
+    }
+
+    /**
+     * A writeable parser for memory size value
+     */
+    public static class MemorySizeValueParser implements Function<String, ByteSizeValue>, Writeable {
+        private String key;
+
+        public MemorySizeValueParser(String key) {
+            this.key = key;
+        }
+
+        public MemorySizeValueParser(StreamInput in) throws IOException {
+            key = in.readString();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(key);
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        @Override
+        public ByteSizeValue apply(String s) {
+            return MemorySizeValue.parseBytesSizeValueOrHeapRatio(s, key);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            MemorySizeValueParser that = (MemorySizeValueParser) obj;
+            return Objects.equals(key, that.key);
+        }
+
+        public int hashCode() {
+            return Objects.hash(key);
+        }
     }
 
     /**
@@ -1884,7 +2345,7 @@ public static <T> Setting<List<T>> listSetting(
     private static List<String> parseableStringToList(String parsableString) {
         // fromXContent doesn't use named xcontent or deprecation.
         try (
-            XContentParser xContentParser = XContentType.JSON.xContent()
+            XContentParser xContentParser = MediaTypeRegistry.JSON.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, parsableString)
         ) {
             XContentParser.Token token = xContentParser.nextToken();
@@ -1906,18 +2367,23 @@ private static List<String> parseableStringToList(String parsableString) {
 
     private static String arrayToParsableString(List<String> array) {
         try {
-            XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+            XContentBuilder builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
             builder.startArray();
             for (String element : array) {
                 builder.value(element);
             }
             builder.endArray();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException ex) {
             throw new OpenSearchException(ex);
         }
     }
 
+    /**
+     * A list setting
+     *
+     * @opensearch.internal
+     */
     private static class ListSetting<T> extends Setting<List<T>> {
 
         private final Function<Settings, List<String>> defaultStringValue;
@@ -2045,6 +2511,63 @@ public static Setting<TimeValue> timeSetting(
         );
     }
 
+    /**
+     * A writeable parser for time value only has min value
+     *
+     */
+    public static class MinTimeValueParser implements Function<String, TimeValue>, Writeable {
+        private String key;
+        private TimeValue minValue;
+        private boolean isFiltered;
+
+        public MinTimeValueParser(String key, TimeValue minValue, boolean isFiltered) {
+            this.key = key;
+            this.minValue = minValue;
+            this.isFiltered = isFiltered;
+        }
+
+        public MinTimeValueParser(StreamInput in) throws IOException {
+            key = in.readString();
+            minValue = in.readTimeValue();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(key);
+            out.writeTimeValue(minValue);
+            out.writeBoolean(isFiltered);
+        }
+
+        public TimeValue getMin() {
+            return minValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public TimeValue apply(String s) {
+            return minTimeValueParser(key, minValue, isFiltered).apply(s);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            MinTimeValueParser that = (MinTimeValueParser) obj;
+            return Objects.equals(key, that.key) && Objects.equals(minValue, that.minValue) && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(key, minValue, isFiltered);
+        }
+    }
+
     public static Setting<TimeValue> timeSetting(
         final String key,
         Function<Settings, TimeValue> defaultValue,
@@ -2055,7 +2578,7 @@ public static Setting<TimeValue> timeSetting(
         return new Setting<>(
             simpleKey,
             s -> defaultValue.apply(s).getStringRep(),
-            minTimeValueParser(key, minValue, isFiltered(properties)),
+            new MinTimeValueParser(key, minValue, isFiltered(properties)),
             properties
         );
     }
@@ -2071,11 +2594,79 @@ public static Setting<TimeValue> timeSetting(
         return new Setting<>(
             simpleKey,
             s -> defaultValue.getStringRep(),
-            minMaxTimeValueParser(key, minValue, maxValue, isFiltered(properties)),
+            new MinMaxTimeValueParser(key, minValue, maxValue, isFiltered(properties)),
             properties
         );
     }
 
+    /**
+     * A writeable parser for time value have min and max value
+     *
+     */
+    public static class MinMaxTimeValueParser implements Function<String, TimeValue>, Writeable {
+        private String key;
+        private TimeValue minValue;
+        private TimeValue maxValue;
+        private boolean isFiltered;
+
+        public MinMaxTimeValueParser(String key, TimeValue minValue, TimeValue maxValue, boolean isFiltered) {
+            this.key = key;
+            this.minValue = minValue;
+            this.maxValue = maxValue;
+            this.isFiltered = isFiltered;
+        }
+
+        public MinMaxTimeValueParser(StreamInput in) throws IOException {
+            key = in.readString();
+            minValue = in.readTimeValue();
+            maxValue = in.readTimeValue();
+            isFiltered = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(key);
+            out.writeTimeValue(minValue);
+            out.writeTimeValue(maxValue);
+            out.writeBoolean(isFiltered);
+        }
+
+        public TimeValue getMin() {
+            return minValue;
+        }
+
+        public TimeValue getMax() {
+            return maxValue;
+        }
+
+        public String getKey() {
+            return key;
+        }
+
+        public boolean getFilterStatus() {
+            return isFiltered;
+        }
+
+        @Override
+        public TimeValue apply(String s) {
+            return minMaxTimeValueParser(key, minValue, maxValue, isFiltered).apply(s);
+        }
+
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            MinMaxTimeValueParser that = (MinMaxTimeValueParser) obj;
+            return Objects.equals(key, that.key)
+                && Objects.equals(minValue, that.minValue)
+                && Objects.equals(maxValue, that.maxValue)
+                && Objects.equals(isFiltered, that.isFiltered);
+        }
+
+        public int hashCode() {
+            return Objects.hash(key, minValue, maxValue, isFiltered);
+        }
+    }
+
     private static Function<String, TimeValue> minTimeValueParser(final String key, final TimeValue minValue, boolean isFiltered) {
         return s -> {
             TimeValue value;
@@ -2145,6 +2736,23 @@ public static Setting<TimeValue> timeSetting(String key, Setting<TimeValue> fall
         return new Setting<>(key, fallbackSetting, (s) -> TimeValue.parseTimeValue(s, key), properties);
     }
 
+    public static Setting<TimeValue> timeSetting(
+        String key,
+        TimeValue defaultValue,
+        TimeValue minValue,
+        Validator<TimeValue> validator,
+        Property... properties
+    ) {
+        final SimpleKey simpleKey = new SimpleKey(key);
+        return new Setting<>(
+            simpleKey,
+            s -> defaultValue.getStringRep(),
+            minTimeValueParser(key, minValue, isFiltered(properties)),
+            validator,
+            properties
+        );
+    }
+
     public static Setting<TimeValue> timeSetting(
         String key,
         Setting<TimeValue> fallBackSetting,
@@ -2230,10 +2838,22 @@ private static <T> AffixSetting<T> affixKeySetting(
         return new AffixSetting<>(key, delegate, delegateFactory, dependencies);
     }
 
+    /**
+     * Key for the setting
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public interface Key {
         boolean match(String key);
     }
 
+    /**
+     * A simple key for a setting
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public static class SimpleKey implements Key {
         protected final String key;
 
@@ -2265,6 +2885,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * Settings Group keys
+     *
+     * @opensearch.internal
+     */
     public static final class GroupKey extends SimpleKey {
         public GroupKey(String key) {
             super(key);
@@ -2279,6 +2904,11 @@ public boolean match(String toTest) {
         }
     }
 
+    /**
+     * List settings key
+     *
+     * @opensearch.internal
+     */
     public static final class ListKey extends SimpleKey {
         private final Pattern pattern;
 
@@ -2296,7 +2926,10 @@ public boolean match(String toTest) {
     /**
      * A key that allows for static pre and suffix. This is used for settings
      * that have dynamic namespaces like for different accounts etc.
+     *
+     * @opensearch.api
      */
+    @PublicApi(since = "1.0.0")
     public static final class AffixKey implements Key {
         private final Pattern pattern;
         private final String prefix;
diff --git a/server/src/main/java/org/opensearch/common/settings/SettingUpgrader.java b/server/src/main/java/org/opensearch/common/settings/SettingUpgrader.java
index d841278b34405..dac0b9b867768 100644
--- a/server/src/main/java/org/opensearch/common/settings/SettingUpgrader.java
+++ b/server/src/main/java/org/opensearch/common/settings/SettingUpgrader.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.common.settings;
 
+import org.opensearch.common.annotation.PublicApi;
+
 import java.util.List;
 
 /**
  * Represents the logic to upgrade a setting.
  *
  * @param <T> the type of the underlying setting
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface SettingUpgrader<T> {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/settings/Settings.java b/server/src/main/java/org/opensearch/common/settings/Settings.java
index 9b9d3f54ffa1b..d3b12a3cb5f88 100644
--- a/server/src/main/java/org/opensearch/common/settings/Settings.java
+++ b/server/src/main/java/org/opensearch/common/settings/Settings.java
@@ -33,30 +33,33 @@
 package org.opensearch.common.settings;
 
 import org.apache.logging.log4j.Level;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchGenerationException;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.logging.LogConfigurator;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.MemorySizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -86,15 +89,19 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static org.opensearch.common.unit.ByteSizeValue.parseBytesSizeValue;
+import static org.opensearch.common.settings.AbstractScopedSettings.ARCHIVED_SETTINGS_PREFIX;
 import static org.opensearch.common.unit.TimeValue.parseTimeValue;
+import static org.opensearch.core.common.unit.ByteSizeValue.parseBytesSizeValue;
 
 /**
  * An immutable settings implementation.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class Settings implements ToXContentFragment {
 
-    public static final Settings EMPTY = new Builder().build();
+    public static final Settings EMPTY = new Settings(Collections.emptyMap(), null);
 
     /** The raw settings from the full key to raw string value. */
     private final Map<String, Object> settings;
@@ -338,6 +345,8 @@ public boolean hasValue(String key) {
      * We have to lazy initialize the deprecation logger as otherwise a static logger here would be constructed before logging is configured
      * leading to a runtime failure (see {@link LogConfigurator#checkErrorListener()} ). The premature construction would come from any
      * {@link Setting} object constructed in, for example, {@link org.opensearch.env.Environment}.
+     *
+     * @opensearch.internal
      */
     static class DeprecationLoggerHolder {
         static DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(Settings.class);
@@ -604,7 +613,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     /**
      * Parsers the generated xcontent from {@link Settings#toXContent(XContentBuilder, Params)} into a new Settings object.
      * Note this method requires the parser to either be positioned on a null token or on
-     * {@link org.opensearch.common.xcontent.XContentParser.Token#START_OBJECT}.
+     * {@link XContentParser.Token#START_OBJECT}.
      */
     public static Settings fromXContent(XContentParser parser) throws IOException {
         return fromXContent(parser, true, false);
@@ -742,10 +751,13 @@ public Set<String> keySet() {
      * A builder allowing to put different settings and then {@link #build()} an immutable
      * settings implementation. Use {@link Settings#builder()} in order to
      * construct it.
+     *
+     * @opensearch.api
      */
+    @PublicApi(since = "1.0.0")
     public static class Builder {
 
-        public static final Settings EMPTY_SETTINGS = new Builder().build();
+        public static final Settings EMPTY_SETTINGS = Settings.EMPTY;
 
         // we use a sorted map for consistent serialization when using getAsMap()
         private final Map<String, Object> map = new TreeMap<>();
@@ -1073,9 +1085,9 @@ private void processLegacyLists(Map<String, Object> map) {
          */
         public Builder loadFromMap(Map<String, ?> map) {
             // TODO: do this without a serialization round-trip
-            try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
                 builder.map(map);
-                return loadFromSource(Strings.toString(builder), builder.contentType());
+                return loadFromSource(builder.toString(), builder.contentType());
             } catch (IOException e) {
                 throw new OpenSearchGenerationException("Failed to generate [" + map + "]", e);
             }
@@ -1084,9 +1096,9 @@ public Builder loadFromMap(Map<String, ?> map) {
         /**
          * Loads settings from the actual string content that represents them using {@link #fromXContent(XContentParser)}
          */
-        public Builder loadFromSource(String source, XContentType xContentType) {
+        public Builder loadFromSource(String source, MediaType mediaType) {
             try (
-                XContentParser parser = XContentFactory.xContent(xContentType)
+                XContentParser parser = mediaType.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, source)
             ) {
                 this.put(fromXContent(parser, true, true));
@@ -1109,17 +1121,17 @@ public Builder loadFromPath(Path path) throws IOException {
          * Loads settings from a stream that represents them using {@link #fromXContent(XContentParser)}
          */
         public Builder loadFromStream(String resourceName, InputStream is, boolean acceptNullValues) throws IOException {
-            final XContentType xContentType;
+            final MediaType mediaType;
             if (resourceName.endsWith(".json")) {
-                xContentType = XContentType.JSON;
+                mediaType = MediaTypeRegistry.JSON;
             } else if (resourceName.endsWith(".yml") || resourceName.endsWith(".yaml")) {
-                xContentType = XContentType.YAML;
+                mediaType = XContentType.YAML;
             } else {
                 throw new IllegalArgumentException("unable to detect content type from resource name [" + resourceName + "]");
             }
             // fromXContent doesn't use named xcontent or deprecation.
             try (
-                XContentParser parser = XContentFactory.xContent(xContentType)
+                XContentParser parser = mediaType.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, is)
             ) {
                 if (parser.currentToken() == null) {
@@ -1209,7 +1221,7 @@ public boolean shouldRemoveMissingPlaceholder(String placeholderName) {
         }
 
         /**
-         * Checks that all settings in the builder start with the specified prefix.
+         * Checks that all settings(except archived settings and wildcards) in the builder start with the specified prefix.
          *
          * If a setting doesn't start with the prefix, the builder appends the prefix to such setting.
          */
@@ -1219,7 +1231,7 @@ public Builder normalizePrefix(String prefix) {
             while (iterator.hasNext()) {
                 Map.Entry<String, Object> entry = iterator.next();
                 String key = entry.getKey();
-                if (key.startsWith(prefix) == false && key.endsWith("*") == false) {
+                if (key.startsWith(prefix) == false && key.endsWith("*") == false && key.startsWith(ARCHIVED_SETTINGS_PREFIX) == false) {
                     replacements.put(prefix + key, entry.getValue());
                     iterator.remove();
                 }
@@ -1357,6 +1369,11 @@ public int size() {
         }
     }
 
+    /**
+     * Prefixed secure settings
+     *
+     * @opensearch.internal
+     */
     private static class PrefixedSecureSettings implements SecureSettings {
         private final SecureSettings delegate;
         private final UnaryOperator<String> addPrefix;
@@ -1414,11 +1431,11 @@ public void close() throws IOException {
 
     @Override
     public String toString() {
-        try (XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent())) {
+        try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
             builder.startObject();
             toXContent(builder, new MapParams(Collections.singletonMap("flat_settings", "true")));
             builder.endObject();
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
diff --git a/server/src/main/java/org/opensearch/common/settings/SettingsException.java b/server/src/main/java/org/opensearch/common/settings/SettingsException.java
index db1c70ae20889..f250d19f79d4a 100644
--- a/server/src/main/java/org/opensearch/common/settings/SettingsException.java
+++ b/server/src/main/java/org/opensearch/common/settings/SettingsException.java
@@ -33,15 +33,17 @@
 package org.opensearch.common.settings;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A generic failure to handle settings.
  *
- *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class SettingsException extends OpenSearchException {
 
     public SettingsException(String message) {
diff --git a/server/src/main/java/org/opensearch/common/settings/SettingsFilter.java b/server/src/main/java/org/opensearch/common/settings/SettingsFilter.java
index 43e6553aba128..1079a02f51c55 100644
--- a/server/src/main/java/org/opensearch/common/settings/SettingsFilter.java
+++ b/server/src/main/java/org/opensearch/common/settings/SettingsFilter.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.common.settings;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.xcontent.ToXContent.Params;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent.Params;
 import org.opensearch.rest.RestRequest;
 
 import java.util.ArrayList;
@@ -47,6 +47,8 @@
 /**
  * A class that allows to filter settings objects by simple regular expression patterns or full settings keys.
  * It's used for response filtering on the rest layer to for instance filter out sensitive information like access keys.
+ *
+ * @opensearch.internal
  */
 public final class SettingsFilter {
     /**
diff --git a/server/src/main/java/org/opensearch/common/settings/SettingsModule.java b/server/src/main/java/org/opensearch/common/settings/SettingsModule.java
index 79ee0bf9f975a..023e8f14e9f8a 100644
--- a/server/src/main/java/org/opensearch/common/settings/SettingsModule.java
+++ b/server/src/main/java/org/opensearch/common/settings/SettingsModule.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.common.settings;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.common.Strings;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.common.inject.Binder;
 import org.opensearch.common.inject.Module;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -54,6 +54,8 @@
 
 /**
  * A module that binds the provided settings to the {@link Settings} interface.
+ *
+ * @opensearch.internal
  */
 public class SettingsModule implements Module {
     private static final Logger logger = LogManager.getLogger(SettingsModule.class);
@@ -84,6 +86,21 @@ public SettingsModule(
         for (Setting<?> setting : IndexScopedSettings.BUILT_IN_INDEX_SETTINGS) {
             registerSetting(setting);
         }
+        for (Setting<?> setting : FeatureFlagSettings.BUILT_IN_FEATURE_FLAGS) {
+            registerSetting(setting);
+        }
+
+        for (Map.Entry<List<String>, List<Setting>> featureFlaggedSetting : ClusterSettings.FEATURE_FLAGGED_CLUSTER_SETTINGS.entrySet()) {
+            if (featureFlaggedSetting.getKey().stream().allMatch(FeatureFlags::isEnabled)) {
+                featureFlaggedSetting.getValue().forEach(this::registerSetting);
+            }
+        }
+
+        for (Map.Entry<String, List<Setting>> featureFlaggedSetting : IndexScopedSettings.FEATURE_FLAGGED_INDEX_SETTINGS.entrySet()) {
+            if (FeatureFlags.isEnabled(featureFlaggedSetting.getKey())) {
+                featureFlaggedSetting.getValue().forEach(this::registerSetting);
+            }
+        }
 
         for (Setting<?> setting : additionalSettings) {
             registerSetting(setting);
@@ -139,12 +156,12 @@ public SettingsModule(
                 builder.append(System.lineSeparator());
                 builder.append(System.lineSeparator());
                 builder.append("curl -XPUT 'http://localhost:9200/_all/_settings?preserve_existing=true' -d '");
-                try (XContentBuilder xContentBuilder = XContentBuilder.builder(XContentType.JSON.xContent())) {
+                try (XContentBuilder xContentBuilder = MediaTypeRegistry.JSON.contentBuilder()) {
                     xContentBuilder.prettyPrint();
                     xContentBuilder.startObject();
                     indexSettings.toXContent(xContentBuilder, new ToXContent.MapParams(Collections.singletonMap("flat_settings", "true")));
                     xContentBuilder.endObject();
-                    builder.append(Strings.toString(xContentBuilder));
+                    builder.append(xContentBuilder);
                 }
                 builder.append("'");
                 builder.append(System.lineSeparator());
@@ -170,6 +187,45 @@ public void configure(Binder binder) {
         binder.bind(IndexScopedSettings.class).toInstance(indexScopedSettings);
     }
 
+    /**
+     * Dynamically registers a new Setting at Runtime. This method is mostly used by plugins/extensions
+     * to register new settings at runtime. Settings can be of Node Scope or Index Scope.
+     * @param setting which is being registered in the cluster.
+     * @return boolean value is set to true when successfully registered, else returns false
+     */
+    public boolean registerDynamicSetting(Setting<?> setting) {
+        boolean onNodeSetting = false;
+        boolean onIndexSetting = false;
+        try {
+            if (setting.hasNodeScope()) {
+                onNodeSetting = clusterSettings.registerSetting(setting);
+            }
+            if (setting.hasIndexScope()) {
+                onIndexSetting = indexScopedSettings.registerSetting(setting);
+            }
+            try {
+                registerSetting(setting);
+                if (onNodeSetting || onIndexSetting) {
+                    logger.info("Registered new Setting: " + setting.getKey() + " successfully ");
+                    return true;
+                }
+            } catch (IllegalArgumentException ex) {
+                if (onNodeSetting) {
+                    clusterSettings.unregisterSetting(setting);
+                }
+
+                if (onIndexSetting) {
+                    indexScopedSettings.unregisterSetting(setting);
+                }
+                throw ex;
+            }
+        } catch (Exception e) {
+            logger.error("Could not register setting " + setting.getKey());
+            throw new SettingsException("Could not register setting:" + setting.getKey());
+        }
+        return false;
+    }
+
     /**
      * Registers a new setting. This method should be used by plugins in order to expose any custom settings the plugin defines.
      * Unless a setting is registered the setting is unusable. If a setting is never the less specified the node will reject
diff --git a/server/src/main/java/org/opensearch/common/settings/UpgradeKeyStoreCommand.java b/server/src/main/java/org/opensearch/common/settings/UpgradeKeyStoreCommand.java
index 36707a8c32428..e3f7439443f0f 100644
--- a/server/src/main/java/org/opensearch/common/settings/UpgradeKeyStoreCommand.java
+++ b/server/src/main/java/org/opensearch/common/settings/UpgradeKeyStoreCommand.java
@@ -38,6 +38,8 @@
 
 /**
  * A sub-command for the keystore CLI that enables upgrading the keystore format.
+ *
+ * @opensearch.internal
  */
 public class UpgradeKeyStoreCommand extends BaseKeyStoreCommand {
 
diff --git a/server/src/main/java/org/opensearch/common/settings/WriteableSetting.java b/server/src/main/java/org/opensearch/common/settings/WriteableSetting.java
new file mode 100644
index 0000000000000..4ca1650611caa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/settings/WriteableSetting.java
@@ -0,0 +1,443 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.settings;
+
+import org.opensearch.Version;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.settings.Setting.ByteSizeValueParser;
+import org.opensearch.common.settings.Setting.DoubleParser;
+import org.opensearch.common.settings.Setting.FloatParser;
+import org.opensearch.common.settings.Setting.IntegerParser;
+import org.opensearch.common.settings.Setting.LongParser;
+import org.opensearch.common.settings.Setting.MemorySizeValueParser;
+import org.opensearch.common.settings.Setting.MinMaxTimeValueParser;
+import org.opensearch.common.settings.Setting.MinTimeValueParser;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Setting.RegexValidator;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.EnumSet;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Wrapper for {@link Setting} with {@link #writeTo(StreamOutput)} implementation dependent on the setting type.
+ *
+ * @opensearch.internal
+ */
+public class WriteableSetting implements Writeable {
+
+    /**
+     * The Generic Types which this class can serialize.
+     */
+    public enum SettingType {
+        Boolean,
+        Integer,
+        Long,
+        Float,
+        Double,
+        String,
+        TimeValue, // long + TimeUnit
+        ByteSizeValue, // long + ByteSizeUnit
+        Version
+    }
+
+    private Setting<?> setting;
+    private SettingType type;
+
+    /**
+     * Wrap a {@link Setting}. The generic type is determined from the type of the default value.
+     *
+     * @param setting  The setting to wrap. The default value must not be null.
+     * @throws IllegalArgumentException if the setting has a null default value.
+     */
+    public WriteableSetting(Setting<?> setting) {
+        this(setting, getGenericTypeFromDefault(setting));
+    }
+
+    /**
+     * Wrap a {@link Setting} with a specified generic type.
+     *
+     * @param setting  The setting to wrap.
+     * @param type  The Generic type of the setting.
+     */
+    public WriteableSetting(Setting<?> setting, SettingType type) {
+        this.setting = setting;
+        this.type = type;
+    }
+
+    /**
+     * Wrap a {@link Setting} read from a stream.
+     *
+     * @param in Input to read the value from.
+     * @throws IOException if there is an error reading the values
+     */
+    public WriteableSetting(StreamInput in) throws IOException {
+        // Read the type
+        this.type = in.readEnum(SettingType.class);
+        // Read the key
+        String key = in.readString();
+        // Read the default value
+        Object defaultValue = readDefaultValue(in);
+        // Read a boolean specifying whether the fallback settings is null
+        WriteableSetting fallback = null;
+        boolean hasFallback = in.readBoolean();
+        if (hasFallback) {
+            fallback = new WriteableSetting(in);
+        }
+        // Read the parser
+        Object parser = null;
+        boolean isParserWriteable = in.readBoolean();
+        if (isParserWriteable) {
+            parser = readParser(in, parser);
+        }
+        // Read the Validator
+        Object validator = new Object();
+        boolean isValidatorWriteable = in.readBoolean();
+        if (isValidatorWriteable) {
+            validator = readValidator(in);
+        }
+        // Read properties
+        EnumSet<Property> propSet = in.readEnumSet(Property.class);
+        // Put it all in a setting object
+        this.setting = createSetting(type, key, defaultValue, parser, validator, fallback, propSet.toArray(Property[]::new));
+    }
+
+    /**
+     * Due to type erasure, it is impossible to determine the generic type of a Setting at runtime.
+     * All settings have a non-null default, however, so the type of the default can be used to determine the setting type.
+     *
+     * @param setting The setting with a generic type.
+     * @return The corresponding {@link SettingType} for the default value.
+     */
+    private static SettingType getGenericTypeFromDefault(Setting<?> setting) {
+        String typeStr = setting.getDefault(Settings.EMPTY).getClass().getSimpleName();
+        try {
+            // This throws IAE if not in enum
+            return SettingType.valueOf(typeStr);
+        } catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException(
+                "This class is not yet set up to handle the generic type: "
+                    + typeStr
+                    + ". Supported types are "
+                    + Arrays.toString(SettingType.values())
+            );
+        }
+    }
+
+    /**
+     * Gets the wrapped setting. Use {@link #getType()} to determine its generic type.
+     *
+     * @return The wrapped setting.
+     */
+    public Setting<?> getSetting() {
+        return this.setting;
+    }
+
+    /**
+     * Gets the generic type of the wrapped setting.
+     *
+     * @return The wrapped setting's generic type.
+     */
+    public SettingType getType() {
+        return this.type;
+    }
+
+    @SuppressWarnings("unchecked")
+    private Setting<?> createSetting(
+        SettingType type,
+        String key,
+        Object defaultValue,
+        @Nullable Object parser,
+        Object validator,
+        WriteableSetting fallback,
+        Property[] propertyArray
+    ) {
+        switch (type) {
+            case Boolean:
+                return fallback == null
+                    ? Setting.boolSetting(key, (boolean) defaultValue, propertyArray)
+                    : Setting.boolSetting(key, (Setting<Boolean>) fallback.getSetting(), propertyArray);
+            case Integer:
+                if (fallback == null && parser instanceof Writeable) {
+                    return Setting.intSetting(
+                        key,
+                        (int) defaultValue,
+                        ((IntegerParser) parser).getMin(),
+                        ((IntegerParser) parser).getMax(),
+                        propertyArray
+                    );
+                } else if (fallback == null) {
+                    return Setting.intSetting(key, (int) defaultValue, propertyArray);
+                }
+                return Setting.intSetting(key, (Setting<Integer>) fallback.getSetting(), propertyArray);
+            case Long:
+                if (fallback == null && parser instanceof Writeable) {
+                    return Setting.longSetting(
+                        key,
+                        (long) defaultValue,
+                        ((LongParser) parser).getMin(),
+                        ((LongParser) parser).getMax(),
+                        propertyArray
+                    );
+                } else if (fallback == null) {
+                    return Setting.longSetting(key, (long) defaultValue, propertyArray);
+                }
+                return Setting.longSetting(key, (Setting<Long>) fallback.getSetting(), propertyArray);
+            case Float:
+                if (fallback == null && parser instanceof Writeable) {
+                    return Setting.floatSetting(
+                        key,
+                        (float) defaultValue,
+                        ((FloatParser) parser).getMin(),
+                        ((FloatParser) parser).getMax(),
+                        propertyArray
+                    );
+                } else if (fallback == null) {
+                    return Setting.floatSetting(key, (float) defaultValue, propertyArray);
+                }
+                return Setting.floatSetting(key, (Setting<Float>) fallback.getSetting(), propertyArray);
+            case Double:
+                if (fallback == null && parser instanceof Writeable) {
+                    return Setting.doubleSetting(
+                        key,
+                        (double) defaultValue,
+                        ((DoubleParser) parser).getMin(),
+                        ((DoubleParser) parser).getMax(),
+                        propertyArray
+                    );
+                } else if (fallback == null) {
+                    return Setting.doubleSetting(key, (double) defaultValue, propertyArray);
+                }
+                return Setting.doubleSetting(key, (Setting<Double>) fallback.getSetting(), propertyArray);
+            case String:
+                return fallback == null
+                    ? Setting.simpleString(key, (String) defaultValue, propertyArray)
+                    : Setting.simpleString(key, (Setting<String>) fallback.getSetting(), propertyArray);
+            case TimeValue:
+                if (fallback == null && parser instanceof Writeable) {
+                    if (parser instanceof MinMaxTimeValueParser) {
+                        return Setting.timeSetting(
+                            key,
+                            (TimeValue) defaultValue,
+                            ((MinMaxTimeValueParser) parser).getMin(),
+                            ((MinMaxTimeValueParser) parser).getMax(),
+                            propertyArray
+                        );
+                    } else {
+                        return Setting.timeSetting(key, (TimeValue) defaultValue, ((MinTimeValueParser) parser).getMin(), propertyArray);
+                    }
+                } else if (fallback == null) {
+                    return Setting.timeSetting(key, (TimeValue) defaultValue, propertyArray);
+                }
+                return Setting.timeSetting(key, (Setting<TimeValue>) fallback.getSetting(), propertyArray);
+            case ByteSizeValue:
+                if (fallback == null && parser instanceof Writeable) {
+                    if (parser instanceof MemorySizeValueParser) {
+                        return Setting.memorySizeSetting(key, (ByteSizeValue) defaultValue, propertyArray);
+                    } else {
+                        ByteSizeValueParser byteSizeValueParser = (ByteSizeValueParser) parser;
+                        return Setting.byteSizeSetting(
+                            key,
+                            (ByteSizeValue) defaultValue,
+                            byteSizeValueParser.getMin(),
+                            byteSizeValueParser.getMax(),
+                            propertyArray
+                        );
+                    }
+                } else if (fallback == null) {
+                    return Setting.byteSizeSetting(key, (ByteSizeValue) defaultValue, propertyArray);
+                }
+                return Setting.byteSizeSetting(key, (Setting<ByteSizeValue>) fallback.getSetting(), propertyArray);
+            case Version:
+                // No fallback option on this method
+                return Setting.versionSetting(key, (Version) defaultValue, propertyArray);
+            default:
+                // This Should Never Happen (TM)
+                throw new IllegalArgumentException("A SettingType has been added to the enum and not handled here.");
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        // Write the type
+        out.writeEnum(type);
+        // Write the key
+        out.writeString(setting.getKey());
+        // Write the default value
+        writeDefaultValue(out, setting.getDefault(Settings.EMPTY));
+        // Write a boolean specifying whether the fallback settings is null
+        boolean hasFallback = setting.fallbackSetting != null;
+        out.writeBoolean(hasFallback);
+        if (hasFallback) {
+            new WriteableSetting(setting.fallbackSetting, type).writeTo(out);
+        }
+        // Write a boolean specifying whether the parser is an instanceof writeable
+        boolean isParserWriteable = setting.parser instanceof Writeable;
+        out.writeBoolean(isParserWriteable);
+        if (isParserWriteable) {
+            writeParser(out, setting.parser);
+        }
+        // Write the validator
+        boolean isValidatorWriteable = setting.validator instanceof Writeable;
+        out.writeBoolean(isValidatorWriteable);
+        if (isValidatorWriteable) {
+            writeValidator(out, setting.validator);
+        }
+        // Write properties
+        out.writeEnumSet(setting.getProperties());
+    }
+
+    private void writeParser(StreamOutput out, Object parser) throws IOException {
+        switch (type) {
+            case Integer:
+                ((IntegerParser) parser).writeTo(out);
+                break;
+            case Long:
+                ((LongParser) parser).writeTo(out);
+                break;
+            case Float:
+                ((FloatParser) parser).writeTo(out);
+                break;
+            case Double:
+                ((DoubleParser) parser).writeTo(out);
+                break;
+            case TimeValue:
+                if (parser instanceof MinMaxTimeValueParser) {
+                    out.writeBoolean(true);
+                    ((MinMaxTimeValueParser) parser).writeTo(out);
+                } else if (parser instanceof MinTimeValueParser) {
+                    out.writeBoolean(false);
+                    ((MinTimeValueParser) parser).writeTo(out);
+                }
+                break;
+            case ByteSizeValue:
+                if (parser instanceof ByteSizeValueParser) {
+                    out.writeBoolean(true);
+                    ((ByteSizeValueParser) parser).writeTo(out);
+                } else if (parser instanceof MemorySizeValueParser) {
+                    out.writeBoolean(false);
+                    ((MemorySizeValueParser) parser).writeTo(out);
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("A SettingType has been added to the enum and not handled here.");
+        }
+    }
+
+    private void writeValidator(StreamOutput out, Object validator) throws IOException {
+        ((Writeable) validator).writeTo(out);
+    }
+
+    private void writeDefaultValue(StreamOutput out, Object defaultValue) throws IOException {
+        switch (type) {
+            case Boolean:
+                out.writeBoolean((boolean) defaultValue);
+                break;
+            case Integer:
+                out.writeInt((int) defaultValue);
+                break;
+            case Long:
+                out.writeLong((long) defaultValue);
+                break;
+            case Float:
+                out.writeFloat((float) defaultValue);
+                break;
+            case Double:
+                out.writeDouble((double) defaultValue);
+                break;
+            case String:
+                out.writeString((String) defaultValue);
+                break;
+            case TimeValue:
+                TimeValue tv = (TimeValue) defaultValue;
+                out.writeLong(tv.duration());
+                out.writeString(tv.timeUnit().name());
+                break;
+            case ByteSizeValue:
+                ((ByteSizeValue) defaultValue).writeTo(out);
+                break;
+            case Version:
+                out.writeVersion((Version) defaultValue);
+                break;
+            default:
+                // This Should Never Happen (TM)
+                throw new IllegalArgumentException("A SettingType has been added to the enum and not handled here.");
+        }
+    }
+
+    private Object readParser(StreamInput in, Object parser) throws IOException {
+        switch (type) {
+            case Integer:
+                return new IntegerParser(in);
+            case Long:
+                return new LongParser(in);
+            case Float:
+                return new FloatParser(in);
+            case Double:
+                return new DoubleParser(in);
+            case TimeValue:
+                if (in.readBoolean()) {
+                    return new MinMaxTimeValueParser(in);
+                } else {
+                    return new MinTimeValueParser(in);
+                }
+            case ByteSizeValue:
+                if (in.readBoolean()) {
+                    return new ByteSizeValueParser(in);
+                } else {
+                    return new MemorySizeValueParser(in);
+                }
+            default:
+                throw new IllegalArgumentException("A SettingType has been added to the enum and not handled here.");
+        }
+    }
+
+    private Object readValidator(StreamInput in) throws IOException {
+        return new RegexValidator(in);
+    }
+
+    private Object readDefaultValue(StreamInput in) throws IOException {
+        switch (type) {
+            case Boolean:
+                return in.readBoolean();
+            case Integer:
+                return in.readInt();
+            case Long:
+                return in.readLong();
+            case Float:
+                return in.readFloat();
+            case Double:
+                return in.readDouble();
+            case String:
+                return in.readString();
+            case TimeValue:
+                long duration = in.readLong();
+                TimeUnit unit = TimeUnit.valueOf(in.readString());
+                return new TimeValue(duration, unit);
+            case ByteSizeValue:
+                return new ByteSizeValue(in);
+            case Version:
+                return in.readVersion();
+            default:
+                // This Should Never Happen (TM)
+                throw new IllegalArgumentException("A SettingType has been added to the enum and not handled here.");
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "WriteableSettings{type=Setting<" + type + ">, setting=" + setting + "}";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/text/package-info.java b/server/src/main/java/org/opensearch/common/text/package-info.java
new file mode 100644
index 0000000000000..229d39aa4ff8d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/text/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Text utility package. */
+package org.opensearch.common.text;
diff --git a/server/src/main/java/org/opensearch/common/time/DateFormatter.java b/server/src/main/java/org/opensearch/common/time/DateFormatter.java
index 4ff810a1c5041..d57fd441b9bf4 100644
--- a/server/src/main/java/org/opensearch/common/time/DateFormatter.java
+++ b/server/src/main/java/org/opensearch/common/time/DateFormatter.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.common.time;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.joda.time.DateTime;
 
 import java.time.Instant;
@@ -46,6 +46,11 @@
 import java.util.Locale;
 import java.util.stream.Collectors;
 
+/**
+ * Base Date formatter
+ *
+ * @opensearch.internal
+ */
 public interface DateFormatter {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/time/DateFormatters.java b/server/src/main/java/org/opensearch/common/time/DateFormatters.java
index bf8b9ea67ea94..6c8b9282d8a77 100644
--- a/server/src/main/java/org/opensearch/common/time/DateFormatters.java
+++ b/server/src/main/java/org/opensearch/common/time/DateFormatters.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.common.time;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.util.LazyInitializable;
+import org.opensearch.core.common.Strings;
 
 import java.time.DayOfWeek;
 import java.time.Instant;
@@ -67,6 +67,11 @@
 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
 import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
 
+/**
+ * Utility of date formatters.
+ *
+ * @opensearch.internal
+ */
 public class DateFormatters {
     // when run with JDK8, WeekFields for Locale.ROOT would return WeekFields.of(DayOfWeek.SUNDAY,1)
     public static final WeekFields WEEK_FIELDS_ROOT = WeekFields.of(DayOfWeek.MONDAY, 4);
diff --git a/server/src/main/java/org/opensearch/common/time/DateMathParser.java b/server/src/main/java/org/opensearch/common/time/DateMathParser.java
index f75f70c35a31f..f6573eaa90286 100644
--- a/server/src/main/java/org/opensearch/common/time/DateMathParser.java
+++ b/server/src/main/java/org/opensearch/common/time/DateMathParser.java
@@ -40,6 +40,8 @@
 
 /**
  * An abstraction over date math parsing to allow different implementation for joda and java time.
+ *
+ * @opensearch.internal
  */
 public interface DateMathParser {
 
diff --git a/server/src/main/java/org/opensearch/common/time/DateUtils.java b/server/src/main/java/org/opensearch/common/time/DateUtils.java
index 4eec4e810af3b..021b8a3be8b23 100644
--- a/server/src/main/java/org/opensearch/common/time/DateUtils.java
+++ b/server/src/main/java/org/opensearch/common/time/DateUtils.java
@@ -51,6 +51,11 @@
 import static org.opensearch.common.time.DateUtilsRounding.getYear;
 import static org.opensearch.common.time.DateUtilsRounding.utcMillisAtStartOfYear;
 
+/**
+ * Date utilities.
+ *
+ * @opensearch.internal
+ */
 public class DateUtils {
     public static DateTimeZone zoneIdToDateTimeZone(ZoneId zoneId) {
         if (zoneId == null) {
diff --git a/server/src/main/java/org/opensearch/common/time/DateUtilsRounding.java b/server/src/main/java/org/opensearch/common/time/DateUtilsRounding.java
index 4b0fa49b76687..f3459a5857b9e 100644
--- a/server/src/main/java/org/opensearch/common/time/DateUtilsRounding.java
+++ b/server/src/main/java/org/opensearch/common/time/DateUtilsRounding.java
@@ -42,6 +42,8 @@
  * - org.joda.time.chrono.BasicChronology.getYear(int year)
  * - org.joda.time.chrono.BasicGJChronology.getMonthOfYear(long utcMillis, int year)
  * - org.joda.time.chrono.BasicGJChronology.getTotalMillisByYearMonth(int year, int month)
+ *
+ * @opensearch.internal
  */
 class DateUtilsRounding {
 
diff --git a/server/src/main/java/org/opensearch/common/time/EpochTime.java b/server/src/main/java/org/opensearch/common/time/EpochTime.java
index 7894a653492c8..19e70fbc2202d 100644
--- a/server/src/main/java/org/opensearch/common/time/EpochTime.java
+++ b/server/src/main/java/org/opensearch/common/time/EpochTime.java
@@ -55,6 +55,8 @@
  * The milliseconds formatter is provided by {@link #MILLIS_FORMATTER}.
  * <p>
  * Both formatters support fractional time, up to nanosecond precision.
+ *
+ * @opensearch.internal
  */
 class EpochTime {
 
@@ -257,7 +259,7 @@ public long getFrom(TemporalAccessor temporal) {
     static final DateFormatter SECONDS_FORMATTER = new JavaDateFormatter(
         "epoch_second",
         SECONDS_FORMATTER1,
-        builder -> builder.parseDefaulting(ChronoField.NANO_OF_SECOND, 999_999_999L),
+        (builder, parser) -> builder.parseDefaulting(ChronoField.NANO_OF_SECOND, 999_999_999L),
         SECONDS_FORMATTER1,
         SECONDS_FORMATTER2
     );
@@ -265,11 +267,16 @@ public long getFrom(TemporalAccessor temporal) {
     static final DateFormatter MILLIS_FORMATTER = new JavaDateFormatter(
         "epoch_millis",
         MILLISECONDS_FORMATTER1,
-        builder -> builder.parseDefaulting(EpochTime.NANOS_OF_MILLI, 999_999L),
+        (builder, parser) -> builder.parseDefaulting(EpochTime.NANOS_OF_MILLI, 999_999L),
         MILLISECONDS_FORMATTER1,
         MILLISECONDS_FORMATTER2
     );
 
+    /**
+     * Base class for an epoch field
+     *
+     * @opensearch.internal
+     */
     private abstract static class EpochField implements TemporalField {
 
         private final TemporalUnit baseUnit;
diff --git a/server/src/main/java/org/opensearch/common/time/FormatNames.java b/server/src/main/java/org/opensearch/common/time/FormatNames.java
index 4e1cfc5df87fc..ba0a8fcf4a17a 100644
--- a/server/src/main/java/org/opensearch/common/time/FormatNames.java
+++ b/server/src/main/java/org/opensearch/common/time/FormatNames.java
@@ -37,6 +37,11 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+/**
+ * Date format names.
+ *
+ * @opensearch.internal
+ */
 public enum FormatNames {
     ISO8601(null, "iso8601"),
     BASIC_DATE("basicDate", "basic_date"),
diff --git a/server/src/main/java/org/opensearch/common/time/IsoCalendarDataProvider.java b/server/src/main/java/org/opensearch/common/time/IsoCalendarDataProvider.java
index f54bacc08f1f9..30a2cde37bbc1 100644
--- a/server/src/main/java/org/opensearch/common/time/IsoCalendarDataProvider.java
+++ b/server/src/main/java/org/opensearch/common/time/IsoCalendarDataProvider.java
@@ -41,6 +41,8 @@
  * This class overrides default behaviour for Locale.ROOT (start of the week Sunday, minimum 1 day in the first week of the year).
  * Java SPI mechanism requires java.locale.providers to contain SPI value (i.e. java.locale.providers=SPI,COMPAT)
  * @see <a href="https://en.wikipedia.org/wiki/ISO_week_date">ISO week date</a>
+ *
+ * @opensearch.internal
  */
 public class IsoCalendarDataProvider extends CalendarDataProvider {
 
diff --git a/server/src/main/java/org/opensearch/common/time/JavaDateFormatter.java b/server/src/main/java/org/opensearch/common/time/JavaDateFormatter.java
index 289dd0fe1ea29..07013a3dc75f2 100644
--- a/server/src/main/java/org/opensearch/common/time/JavaDateFormatter.java
+++ b/server/src/main/java/org/opensearch/common/time/JavaDateFormatter.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.common.time;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.text.ParsePosition;
 import java.time.ZoneId;
@@ -51,21 +51,19 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
 class JavaDateFormatter implements DateFormatter {
 
     // base fields which should be used for default parsing, when we round up for date math
-    private static final Map<TemporalField, Long> ROUND_UP_BASE_FIELDS = new HashMap<>(6);
+    private static final Map<TemporalField, Long> ROUND_UP_GENERIC_BASE_FIELDS = new HashMap<>(4);
 
     {
-        ROUND_UP_BASE_FIELDS.put(ChronoField.MONTH_OF_YEAR, 1L);
-        ROUND_UP_BASE_FIELDS.put(ChronoField.DAY_OF_MONTH, 1L);
-        ROUND_UP_BASE_FIELDS.put(ChronoField.HOUR_OF_DAY, 23L);
-        ROUND_UP_BASE_FIELDS.put(ChronoField.MINUTE_OF_HOUR, 59L);
-        ROUND_UP_BASE_FIELDS.put(ChronoField.SECOND_OF_MINUTE, 59L);
-        ROUND_UP_BASE_FIELDS.put(ChronoField.NANO_OF_SECOND, 999_999_999L);
+        ROUND_UP_GENERIC_BASE_FIELDS.put(ChronoField.HOUR_OF_DAY, 23L);
+        ROUND_UP_GENERIC_BASE_FIELDS.put(ChronoField.MINUTE_OF_HOUR, 59L);
+        ROUND_UP_GENERIC_BASE_FIELDS.put(ChronoField.SECOND_OF_MINUTE, 59L);
+        ROUND_UP_GENERIC_BASE_FIELDS.put(ChronoField.NANO_OF_SECOND, 999_999_999L);
     }
 
     private final String format;
@@ -73,6 +71,11 @@ class JavaDateFormatter implements DateFormatter {
     private final List<DateTimeFormatter> parsers;
     private final JavaDateFormatter roundupParser;
 
+    /**
+     * A round up formatter
+     *
+     * @opensearch.internal
+     */
     static class RoundUpFormatter extends JavaDateFormatter {
 
         RoundUpFormatter(String format, List<DateTimeFormatter> roundUpParsers) {
@@ -91,14 +94,25 @@ JavaDateFormatter getRoundupParser() {
 
     // named formatters use default roundUpParser
     JavaDateFormatter(String format, DateTimeFormatter printer, DateTimeFormatter... parsers) {
-        this(format, printer, builder -> ROUND_UP_BASE_FIELDS.forEach(builder::parseDefaulting), parsers);
+        this(format, printer, ROUND_UP_BASE_FIELDS, parsers);
     }
 
+    private static final BiConsumer<DateTimeFormatterBuilder, DateTimeFormatter> ROUND_UP_BASE_FIELDS = (builder, parser) -> {
+        String parserString = parser.toString();
+        if (parserString.contains(ChronoField.DAY_OF_YEAR.toString())) {
+            builder.parseDefaulting(ChronoField.DAY_OF_YEAR, 1L);
+        } else {
+            builder.parseDefaulting(ChronoField.MONTH_OF_YEAR, 1L);
+            builder.parseDefaulting(ChronoField.DAY_OF_MONTH, 1L);
+        }
+        ROUND_UP_GENERIC_BASE_FIELDS.forEach(builder::parseDefaulting);
+    };
+
     // subclasses override roundUpParser
     JavaDateFormatter(
         String format,
         DateTimeFormatter printer,
-        Consumer<DateTimeFormatterBuilder> roundupParserConsumer,
+        BiConsumer<DateTimeFormatterBuilder, DateTimeFormatter> roundupParserConsumer,
         DateTimeFormatter... parsers
     ) {
         if (printer == null) {
@@ -133,13 +147,16 @@ JavaDateFormatter getRoundupParser() {
      * <code>DateFormatters</code>.
      * This means that we need to also have multiple RoundUp parsers.
      */
-    private List<DateTimeFormatter> createRoundUpParser(String format, Consumer<DateTimeFormatterBuilder> roundupParserConsumer) {
+    private List<DateTimeFormatter> createRoundUpParser(
+        String format,
+        BiConsumer<DateTimeFormatterBuilder, DateTimeFormatter> roundupParserConsumer
+    ) {
         if (format.contains("||") == false) {
             List<DateTimeFormatter> roundUpParsers = new ArrayList<>();
             for (DateTimeFormatter parser : this.parsers) {
                 DateTimeFormatterBuilder builder = new DateTimeFormatterBuilder();
                 builder.append(parser);
-                roundupParserConsumer.accept(builder);
+                roundupParserConsumer.accept(builder, parser);
                 roundUpParsers.add(builder.toFormatter(locale()));
             }
             return roundUpParsers;
diff --git a/server/src/main/java/org/opensearch/common/time/JavaDateMathParser.java b/server/src/main/java/org/opensearch/common/time/JavaDateMathParser.java
index 87119002b070e..0536324b6516b 100644
--- a/server/src/main/java/org/opensearch/common/time/JavaDateMathParser.java
+++ b/server/src/main/java/org/opensearch/common/time/JavaDateMathParser.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.time;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.time.DayOfWeek;
 import java.time.Instant;
@@ -55,6 +55,8 @@
  * The format of the datetime is configurable, and unix timestamps can also be used. Datemath
  * is appended to a datetime with the following syntax:
  * <code>||[+-/](\d+)?[yMwdhHms]</code>.
+ *
+ * @opensearch.internal
  */
 public class JavaDateMathParser implements DateMathParser {
 
diff --git a/server/src/main/java/org/opensearch/common/time/package-info.java b/server/src/main/java/org/opensearch/common/time/package-info.java
new file mode 100644
index 0000000000000..8e946aa8a3b1b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/time/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Time utility package. */
+package org.opensearch.common.time;
diff --git a/server/src/main/java/org/opensearch/common/unit/DistanceUnit.java b/server/src/main/java/org/opensearch/common/unit/DistanceUnit.java
index a4df3c6b5902d..e97438f0f47c0 100644
--- a/server/src/main/java/org/opensearch/common/unit/DistanceUnit.java
+++ b/server/src/main/java/org/opensearch/common/unit/DistanceUnit.java
@@ -33,9 +33,9 @@
 package org.opensearch.common.unit;
 
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
@@ -45,6 +45,8 @@
  * others. Some methods like {@link DistanceUnit#getEarthCircumference} refer to
  * the earth ellipsoid defined in {@link GeoUtils}. The default unit used within
  * this project is <code>METERS</code> which is defined by <code>DEFAULT</code>
+ *
+ * @opensearch.internal
  */
 public enum DistanceUnit implements Writeable {
     INCH(0.0254, "in", "inch"),
@@ -225,6 +227,8 @@ public static DistanceUnit parseUnit(String distance, DistanceUnit defaultUnit)
 
     /**
      * This class implements a value+unit tuple.
+     *
+     * @opensearch.internal
      */
     public static class Distance implements Comparable<Distance> {
         public final double value;
diff --git a/server/src/main/java/org/opensearch/common/unit/Fuzziness.java b/server/src/main/java/org/opensearch/common/unit/Fuzziness.java
index 8b10d88235142..2ce86cbfd13f3 100644
--- a/server/src/main/java/org/opensearch/common/unit/Fuzziness.java
+++ b/server/src/main/java/org/opensearch/common/unit/Fuzziness.java
@@ -32,13 +32,13 @@
 package org.opensearch.common.unit;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -48,6 +48,8 @@
  * A unit class that encapsulates all in-exact search
  * parsing and conversion from similarities to edit distances
  * etc.
+ *
+ * @opensearch.internal
  */
 public final class Fuzziness implements ToXContentFragment, Writeable {
 
@@ -137,6 +139,16 @@ public static Fuzziness build(Object fuzziness) {
         return new Fuzziness(string);
     }
 
+    /***
+     * Creates a {@link Fuzziness} instance from lowDistance and highDistance.
+     * where the edit distance is 0 for strings shorter than lowDistance,
+     * 1 for strings where its length between lowDistance and highDistance (inclusive),
+     * and 2 for strings longer than highDistance.
+     */
+    public static Fuzziness customAuto(int lowDistance, int highDistance) {
+        return new Fuzziness("AUTO", lowDistance, highDistance);
+    }
+
     private static Fuzziness parseCustomAuto(final String string) {
         assert string.toUpperCase(Locale.ROOT).startsWith(AUTO.asString() + ":");
         String[] fuzzinessLimit = string.substring(AUTO.asString().length() + 1).split(",");
@@ -166,6 +178,9 @@ public static Fuzziness parse(XContentParser parser) throws IOException {
                 }
                 try {
                     final int minimumSimilarity = Integer.parseInt(fuzziness);
+                    if (minimumSimilarity < 0) {
+                        throw new IllegalArgumentException("Invalid fuzziness value: " + fuzziness);
+                    }
                     switch (minimumSimilarity) {
                         case 0:
                             return ZERO;
@@ -177,7 +192,16 @@ public static Fuzziness parse(XContentParser parser) throws IOException {
                             return build(fuzziness);
                     }
                 } catch (NumberFormatException ex) {
-                    return build(fuzziness);
+                    // Validate if the fuzziness value is formatted correctly as a numeric value.
+                    try {
+                        final float minimumSimilarity = Float.parseFloat(fuzziness);
+                        if (minimumSimilarity < 0.0f || Float.isInfinite(minimumSimilarity) || Float.isNaN(minimumSimilarity)) {
+                            throw new IllegalArgumentException("Invalid fuzziness value: " + fuzziness);
+                        }
+                        return build(fuzziness);
+                    } catch (NumberFormatException e) {
+                        throw new IllegalArgumentException("Invalid fuzziness value: " + fuzziness);
+                    }
                 }
 
             default:
@@ -213,7 +237,7 @@ public float asFloat() {
         if (this.equals(AUTO) || isAutoWithCustomValues()) {
             return 1f;
         }
-        return Float.parseFloat(fuzziness.toString());
+        return Float.parseFloat(fuzziness);
     }
 
     private int termLen(String text) {
@@ -222,9 +246,9 @@ private int termLen(String text) {
 
     public String asString() {
         if (isAutoWithCustomValues()) {
-            return fuzziness.toString() + ":" + lowDistance + "," + highDistance;
+            return fuzziness + ":" + lowDistance + "," + highDistance;
         }
-        return fuzziness.toString();
+        return fuzziness;
     }
 
     private boolean isAutoWithCustomValues() {
diff --git a/server/src/main/java/org/opensearch/common/unit/MemorySizeValue.java b/server/src/main/java/org/opensearch/common/unit/MemorySizeValue.java
index ef212762c3ffe..96f128cb6dc38 100644
--- a/server/src/main/java/org/opensearch/common/unit/MemorySizeValue.java
+++ b/server/src/main/java/org/opensearch/common/unit/MemorySizeValue.java
@@ -33,13 +33,19 @@
 package org.opensearch.common.unit;
 
 import org.opensearch.OpenSearchParseException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.monitor.jvm.JvmInfo;
 
 import java.util.Objects;
 
-import static org.opensearch.common.unit.ByteSizeValue.parseBytesSizeValue;
+import static org.opensearch.core.common.unit.ByteSizeValue.parseBytesSizeValue;
 
-/** Utility methods to get memory sizes. */
+/**
+ * Utility methods to get memory sizes.
+ *
+ * @opensearch.internal
+ */
 public enum MemorySizeValue {
     ;
 
diff --git a/server/src/main/java/org/opensearch/common/unit/RatioValue.java b/server/src/main/java/org/opensearch/common/unit/RatioValue.java
index 00cd999ed6264..7f1840dae0fc7 100644
--- a/server/src/main/java/org/opensearch/common/unit/RatioValue.java
+++ b/server/src/main/java/org/opensearch/common/unit/RatioValue.java
@@ -36,6 +36,8 @@
 
 /**
  * Utility class to represent ratio and percentage values between 0 and 100
+ *
+ * @opensearch.internal
  */
 public class RatioValue {
     private final double percent;
diff --git a/server/src/main/java/org/opensearch/common/unit/SizeUnit.java b/server/src/main/java/org/opensearch/common/unit/SizeUnit.java
index 8ceb0bc9f5360..a9491ef1919ed 100644
--- a/server/src/main/java/org/opensearch/common/unit/SizeUnit.java
+++ b/server/src/main/java/org/opensearch/common/unit/SizeUnit.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.unit;
 
+/**
+ * Utility classe for size units.
+ *
+ * @opensearch.internal
+ */
 public enum SizeUnit {
     SINGLE {
         @Override
diff --git a/server/src/main/java/org/opensearch/common/unit/SizeValue.java b/server/src/main/java/org/opensearch/common/unit/SizeValue.java
index 1a644823d3dd9..766199ebbc8f8 100644
--- a/server/src/main/java/org/opensearch/common/unit/SizeValue.java
+++ b/server/src/main/java/org/opensearch/common/unit/SizeValue.java
@@ -33,13 +33,18 @@
 package org.opensearch.common.unit;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Conversion values.
+ *
+ * @opensearch.internal
+ */
 public class SizeValue implements Writeable, Comparable<SizeValue> {
 
     private final long size;
diff --git a/server/src/main/java/org/opensearch/common/unit/package-info.java b/server/src/main/java/org/opensearch/common/unit/package-info.java
new file mode 100644
index 0000000000000..5c5e1b17e55a6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/unit/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Units of Measure utility package. */
+package org.opensearch.common.unit;
diff --git a/server/src/main/java/org/opensearch/common/util/AbstractArray.java b/server/src/main/java/org/opensearch/common/util/AbstractArray.java
index 3833b479c946f..4f6740c6eb89c 100644
--- a/server/src/main/java/org/opensearch/common/util/AbstractArray.java
+++ b/server/src/main/java/org/opensearch/common/util/AbstractArray.java
@@ -33,11 +33,17 @@
 package org.opensearch.common.util;
 
 import org.apache.lucene.util.Accountable;
+import org.opensearch.core.common.util.BigArray;
 
 import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+/**
+ * Base array
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractArray implements BigArray {
 
     private final BigArrays bigArrays;
diff --git a/server/src/main/java/org/opensearch/common/util/AbstractBigArray.java b/server/src/main/java/org/opensearch/common/util/AbstractBigArray.java
index 4b18ebba81045..e8fd3990befa8 100644
--- a/server/src/main/java/org/opensearch/common/util/AbstractBigArray.java
+++ b/server/src/main/java/org/opensearch/common/util/AbstractBigArray.java
@@ -40,7 +40,11 @@
 import java.lang.reflect.Array;
 import java.util.Arrays;
 
-/** Common implementation for array lists that slice data into fixed-size blocks. */
+/**
+ * Common implementation for array lists that slice data into fixed-size blocks.
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractBigArray extends AbstractArray {
 
     private final PageCacheRecycler recycler;
diff --git a/server/src/main/java/org/opensearch/common/util/AbstractHash.java b/server/src/main/java/org/opensearch/common/util/AbstractHash.java
index edf4d93ef410a..ce12a4f5d1bf2 100644
--- a/server/src/main/java/org/opensearch/common/util/AbstractHash.java
+++ b/server/src/main/java/org/opensearch/common/util/AbstractHash.java
@@ -37,6 +37,8 @@
 /**
  * Base implementation for {@link BytesRefHash} and {@link LongHash}, or any class that
  * needs to map values to dense ords. This class is not thread-safe.
+ *
+ * @opensearch.internal
  */
 // IDs are internally stored as id + 1 so that 0 encodes for an empty slot
 abstract class AbstractHash extends AbstractPagedHashMap {
diff --git a/server/src/main/java/org/opensearch/common/util/AbstractPagedHashMap.java b/server/src/main/java/org/opensearch/common/util/AbstractPagedHashMap.java
index bc76bfa52404d..450dcc833a7b3 100644
--- a/server/src/main/java/org/opensearch/common/util/AbstractPagedHashMap.java
+++ b/server/src/main/java/org/opensearch/common/util/AbstractPagedHashMap.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.opensearch.common.lease.Releasable;
 
 /**
  * Base implementation for a hash table that is paged, recycles arrays and grows in-place.
+ *
+ * @opensearch.internal
  */
 abstract class AbstractPagedHashMap implements Releasable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/ArrayUtils.java b/server/src/main/java/org/opensearch/common/util/ArrayUtils.java
index ccd6a51ff505d..6a01d9b3901e5 100644
--- a/server/src/main/java/org/opensearch/common/util/ArrayUtils.java
+++ b/server/src/main/java/org/opensearch/common/util/ArrayUtils.java
@@ -35,6 +35,11 @@
 import java.lang.reflect.Array;
 import java.util.Arrays;
 
+/**
+ * Array utilities.
+ *
+ * @opensearch.internal
+ */
 public class ArrayUtils {
 
     private ArrayUtils() {}
diff --git a/server/src/main/java/org/opensearch/common/util/BigArrays.java b/server/src/main/java/org/opensearch/common/util/BigArrays.java
index e877f75bd2a0f..59c84ea45a65a 100644
--- a/server/src/main/java/org/opensearch/common/util/BigArrays.java
+++ b/server/src/main/java/org/opensearch/common/util/BigArrays.java
@@ -36,12 +36,14 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.recycler.Recycler;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.util.BigArray;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 
 import java.util.Arrays;
 
@@ -84,6 +86,11 @@ static boolean indexIsInt(long index) {
         return index == (int) index;
     }
 
+    /**
+     * Base array wrapper class
+     *
+     * @opensearch.internal
+     */
     private abstract static class AbstractArrayWrapper extends AbstractArray implements BigArray {
 
         static final long SHALLOW_SIZE = RamUsageEstimator.shallowSizeOfInstance(ByteArrayWrapper.class);
@@ -109,6 +116,11 @@ protected final void doClose() {
 
     }
 
+    /**
+     * Wraps a byte array
+     *
+     * @opensearch.internal
+     */
     private static class ByteArrayWrapper extends AbstractArrayWrapper implements ByteArray {
 
         private final byte[] array;
@@ -170,6 +182,11 @@ public byte[] array() {
         }
     }
 
+    /**
+     * Wraps an int array
+     *
+     * @opensearch.internal
+     */
     private static class IntArrayWrapper extends AbstractArrayWrapper implements IntArray {
 
         private final int[] array;
@@ -213,6 +230,11 @@ public void fill(long fromIndex, long toIndex, int value) {
 
     }
 
+    /**
+     * Wraps a long array
+     *
+     * @opensearch.internal
+     */
     private static class LongArrayWrapper extends AbstractArrayWrapper implements LongArray {
 
         private final long[] array;
@@ -255,6 +277,11 @@ public void fill(long fromIndex, long toIndex, long value) {
         }
     }
 
+    /**
+     * Wraps a double array
+     *
+     * @opensearch.internal
+     */
     private static class DoubleArrayWrapper extends AbstractArrayWrapper implements DoubleArray {
 
         private final long[] array;
@@ -298,6 +325,11 @@ public void fill(long fromIndex, long toIndex, double value) {
 
     }
 
+    /**
+     * Wraps a float array
+     *
+     * @opensearch.internal
+     */
     private static class FloatArrayWrapper extends AbstractArrayWrapper implements FloatArray {
 
         private final int[] array;
@@ -341,6 +373,11 @@ public void fill(long fromIndex, long toIndex, float value) {
 
     }
 
+    /**
+     * Wraps an object array
+     *
+     * @opensearch.internal
+     */
     private static class ObjectArrayWrapper<T> extends AbstractArrayWrapper implements ObjectArray<T> {
 
         private final Object[] array;
@@ -716,6 +753,11 @@ public DoubleArray grow(DoubleArray array, long minSize) {
         return resize(array, newSize);
     }
 
+    /**
+     * A double value binary searcher
+     *
+     * @opensearch.internal
+     */
     public static class DoubleBinarySearcher extends BinarySearcher {
 
         DoubleArray array;
diff --git a/server/src/main/java/org/opensearch/common/util/BigByteArray.java b/server/src/main/java/org/opensearch/common/util/BigByteArray.java
index 6dac5ec705ad2..5a715cf56108f 100644
--- a/server/src/main/java/org/opensearch/common/util/BigByteArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigByteArray.java
@@ -35,6 +35,7 @@
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.RamUsageEstimator;
+import org.opensearch.core.common.util.ByteArray;
 
 import java.util.Arrays;
 
@@ -43,6 +44,8 @@
 /**
  * Byte array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigByteArray extends AbstractBigArray implements ByteArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BigDoubleArray.java b/server/src/main/java/org/opensearch/common/util/BigDoubleArray.java
index ad75f13c80a8c..c66b0720d0a85 100644
--- a/server/src/main/java/org/opensearch/common/util/BigDoubleArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigDoubleArray.java
@@ -42,6 +42,8 @@
 /**
  * Double array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigDoubleArray extends AbstractBigArray implements DoubleArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BigFloatArray.java b/server/src/main/java/org/opensearch/common/util/BigFloatArray.java
index 5935e02f9a920..028248c3cc961 100644
--- a/server/src/main/java/org/opensearch/common/util/BigFloatArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigFloatArray.java
@@ -42,6 +42,8 @@
 /**
  * Float array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigFloatArray extends AbstractBigArray implements FloatArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BigIntArray.java b/server/src/main/java/org/opensearch/common/util/BigIntArray.java
index d403d99e285c9..03ae3e642df3d 100644
--- a/server/src/main/java/org/opensearch/common/util/BigIntArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigIntArray.java
@@ -42,6 +42,8 @@
 /**
  * Int array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigIntArray extends AbstractBigArray implements IntArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BigLongArray.java b/server/src/main/java/org/opensearch/common/util/BigLongArray.java
index 23a72706fccdd..19f954eca2d64 100644
--- a/server/src/main/java/org/opensearch/common/util/BigLongArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigLongArray.java
@@ -42,6 +42,8 @@
 /**
  * Long array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigLongArray extends AbstractBigArray implements LongArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BigObjectArray.java b/server/src/main/java/org/opensearch/common/util/BigObjectArray.java
index c90e74efb1672..6fb5662686a34 100644
--- a/server/src/main/java/org/opensearch/common/util/BigObjectArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BigObjectArray.java
@@ -42,6 +42,8 @@
 /**
  * Int array abstraction able to support more than 2B values. This implementation slices data into fixed-sized blocks of
  * configurable length.
+ *
+ * @opensearch.internal
  */
 final class BigObjectArray<T> extends AbstractBigArray implements ObjectArray<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BinarySearcher.java b/server/src/main/java/org/opensearch/common/util/BinarySearcher.java
index 5807fc192ab62..ca63c170c0ccd 100644
--- a/server/src/main/java/org/opensearch/common/util/BinarySearcher.java
+++ b/server/src/main/java/org/opensearch/common/util/BinarySearcher.java
@@ -43,6 +43,8 @@
  * Refer to {@link BigArrays.DoubleBinarySearcher} for an example.
  *
  * NOTE: this class is not thread safe
+ *
+ * @opensearch.internal
  */
 public abstract class BinarySearcher {
 
diff --git a/server/src/main/java/org/opensearch/common/util/BitArray.java b/server/src/main/java/org/opensearch/common/util/BitArray.java
index 57ad5ae326c03..b75a5d07e70d7 100644
--- a/server/src/main/java/org/opensearch/common/util/BitArray.java
+++ b/server/src/main/java/org/opensearch/common/util/BitArray.java
@@ -40,6 +40,8 @@
  * created from {@link BigArrays}.
  * The underlying long array grows lazily based on the biggest index
  * that needs to be set.
+ *
+ * @opensearch.internal
  */
 public final class BitArray implements Releasable {
     private final BigArrays bigArrays;
diff --git a/server/src/main/java/org/opensearch/common/util/ByteUtils.java b/server/src/main/java/org/opensearch/common/util/ByteUtils.java
index b0054bc1a06b7..8c7665d991751 100644
--- a/server/src/main/java/org/opensearch/common/util/ByteUtils.java
+++ b/server/src/main/java/org/opensearch/common/util/ByteUtils.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
-/** Utility methods to do byte-level encoding. These methods are biased towards little-endian byte order because it is the most
- *  common byte order and reading several bytes at once may be optimizable in the future with the help of sun.mist.Unsafe. */
+/**
+ * Utility methods to do byte-level encoding. These methods are biased towards little-endian byte order because it is the most
+ * common byte order and reading several bytes at once may be optimizable in the future with the help of sun.mist.Unsafe.
+ *
+ * @opensearch.internal
+ */
 public final class ByteUtils {
 
     private ByteUtils() {};
@@ -57,6 +61,16 @@ public static void writeLongLE(long l, byte[] arr, int offset) {
         assert l == 0;
     }
 
+    /** Convert long to a byte array in big-endian format */
+    public static byte[] toByteArrayBE(long l) {
+        byte[] result = new byte[8];
+        for (int i = 7; i >= 0; i--) {
+            result[i] = (byte) (l & 0xffL);
+            l >>= 8;
+        }
+        return result;
+    }
+
     /** Write a long in little-endian format. */
     public static long readLongLE(byte[] arr, int offset) {
         long l = arr[offset++] & 0xFFL;
diff --git a/server/src/main/java/org/opensearch/common/util/BytesRefHash.java b/server/src/main/java/org/opensearch/common/util/BytesRefHash.java
index 5de58016de372..4afba2905019a 100644
--- a/server/src/main/java/org/opensearch/common/util/BytesRefHash.java
+++ b/server/src/main/java/org/opensearch/common/util/BytesRefHash.java
@@ -32,151 +32,293 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.Numbers;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.hash.T1ha1;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.core.common.util.ByteArray;
 
 /**
- *  Specialized hash table implementation similar to Lucene's BytesRefHash that maps
- *  BytesRef values to ids. Collisions are resolved with open addressing and linear
- *  probing, growth is smooth thanks to {@link BigArrays}, hashes are cached for faster
- *  re-hashing and capacity is always a multiple of 2 for faster identification of buckets.
- *  This class is not thread-safe.
+ * Specialized hash table implementation that maps a {@link BytesRef} key to a long ordinal.
+ *
+ * <p>
+ * It uses a compact byte-packing strategy to encode the ordinal and fingerprint information
+ * in the hash table value. It makes lookups faster by short-circuiting expensive equality checks
+ * for keys that collide onto the same hash table slot.
+ *
+ * <p>
+ * This class is not thread-safe.
+ *
+ * @opensearch.internal
  */
-public final class BytesRefHash extends AbstractHash {
+@InternalApi
+public final class BytesRefHash implements Releasable {
+    private static final long MAX_CAPACITY = 1L << 32;
+    private static final long DEFAULT_INITIAL_CAPACITY = 32;
+    private static final float DEFAULT_LOAD_FACTOR = 0.6f;
+    private static final Hasher DEFAULT_HASHER = key -> T1ha1.hash(key.bytes, key.offset, key.length);
+
+    private static final long MASK_ORDINAL = 0x00000000FFFFFFFFL;  // extract ordinal
+    private static final long MASK_FINGERPRINT = 0xFFFFFFFF00000000L;  // extract fingerprint
+
+    /**
+     * Maximum load factor after which the capacity is doubled.
+     */
+    private final float loadFactor;
+
+    /**
+     * Calculates the hash of a {@link BytesRef} key.
+     */
+    private final Hasher hasher;
+
+    /**
+     * Utility class to allocate recyclable arrays.
+     */
+    private final BigArrays bigArrays;
+
+    /**
+     * Reusable BytesRef to read keys.
+     */
+    private final BytesRef scratch = new BytesRef();
+
+    /**
+     * Current capacity of the hash table. This must be a power of two so that the hash table slot
+     * can be identified quickly using bitmasks, thus avoiding expensive modulo or integer division.
+     */
+    private long capacity;
+
+    /**
+     * Bitmask to identify the hash table slot from a key's hash.
+     */
+    private long mask;
+
+    /**
+     * Size threshold after which the hash table needs to be doubled in capacity.
+     */
+    private long grow;
+
+    /**
+     * Current size of the hash table.
+     */
+    private long size;
 
-    private LongArray startOffsets;
-    private ByteArray bytes;
-    private IntArray hashes; // we cache hashes for faster re-hashing
-    private final BytesRef spare;
+    /**
+     * Underlying array to store the hash table values.
+     *
+     * <p>
+     * Each hash table value (64-bit) uses the following byte packing strategy:
+     * <pre>
+     * |================================|================================|
+     * | Fingerprint                    | Ordinal                        |
+     * |--------------------------------|--------------------------------|
+     * | 32 bits                        | 32 bits                        |
+     * |================================|================================|
+     * </pre>
+     *
+     * <p>
+     * This allows us to encode and manipulate additional information in the hash table
+     * itself without having to look elsewhere in the memory, which is much slower.
+     *
+     * <p>
+     * Terminology: <code>table[index] = value = (fingerprint | ordinal)</code>
+     */
+    private LongArray table;
+
+    /**
+     * Underlying array to store the starting offsets of keys.
+     *
+     * <p>
+     * Terminology:
+     * <pre>
+     *   offsets[ordinal] = starting offset (inclusive)
+     *   offsets[ordinal + 1] = ending offset (exclusive)
+     * </pre>
+     */
+    private LongArray offsets;
+
+    /**
+     * Underlying byte array to store the keys.
+     *
+     * <p>
+     * Terminology: <code>keys[start...end] = key</code>
+     */
+    private ByteArray keys;
 
-    // Constructor with configurable capacity and default maximum load factor.
-    public BytesRefHash(long capacity, BigArrays bigArrays) {
-        this(capacity, DEFAULT_MAX_LOAD_FACTOR, bigArrays);
+    /**
+     * Pre-computed hashes of the stored keys.
+     * It is used to speed up reinserts when doubling the capacity.
+     */
+    private LongArray hashes;
+
+    public BytesRefHash(final BigArrays bigArrays) {
+        this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_HASHER, bigArrays);
     }
 
-    // Constructor with configurable capacity and load factor.
-    public BytesRefHash(long capacity, float maxLoadFactor, BigArrays bigArrays) {
-        super(capacity, maxLoadFactor, bigArrays);
-        startOffsets = bigArrays.newLongArray(capacity + 1, false);
-        startOffsets.set(0, 0);
-        bytes = bigArrays.newByteArray(capacity * 3, false);
-        hashes = bigArrays.newIntArray(capacity, false);
-        spare = new BytesRef();
+    public BytesRefHash(final long initialCapacity, final BigArrays bigArrays) {
+        this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_HASHER, bigArrays);
     }
 
-    // BytesRef has a weak hashCode function so we try to improve it by rehashing using Murmur3
-    // Feel free to remove rehashing if BytesRef gets a better hash function
-    private static int rehash(int hash) {
-        return BitMixer.mix32(hash);
+    public BytesRefHash(final long initialCapacity, final float loadFactor, final BigArrays bigArrays) {
+        this(initialCapacity, loadFactor, DEFAULT_HASHER, bigArrays);
     }
 
-    /**
-     * Return the key at <code>0 &lt;= index &lt;= capacity()</code>. The result is undefined if the slot is unused.
-     * <p>Beware that the content of the {@link BytesRef} may become invalid as soon as {@link #close()} is called</p>
-     */
-    public BytesRef get(long id, BytesRef dest) {
-        final long startOffset = startOffsets.get(id);
-        final int length = (int) (startOffsets.get(id + 1) - startOffset);
-        bytes.get(startOffset, length, dest);
-        return dest;
+    public BytesRefHash(final long initialCapacity, final float loadFactor, final Hasher hasher, final BigArrays bigArrays) {
+        assert initialCapacity > 0 : "initial capacity must be greater than 0";
+        assert loadFactor > 0 && loadFactor < 1 : "load factor must be between 0 and 1";
+
+        this.loadFactor = loadFactor;
+        this.hasher = hasher;
+        this.bigArrays = bigArrays;
+
+        capacity = Numbers.nextPowerOfTwo((long) (initialCapacity / loadFactor));
+        assert capacity <= MAX_CAPACITY : "required capacity too large";
+        mask = capacity - 1;
+        size = 0;
+        grow = (long) (capacity * loadFactor);
+
+        table = bigArrays.newLongArray(capacity, false);
+        table.fill(0, capacity, -1);
+        offsets = bigArrays.newLongArray(initialCapacity + 1, false);
+        offsets.set(0, 0);
+        keys = bigArrays.newByteArray(initialCapacity * 3, false);
+        hashes = bigArrays.newLongArray(initialCapacity, false);
     }
 
     /**
-     * Get the id associated with <code>key</code>
+     * Adds the given key to the hash table and returns its ordinal.
+     * If the key exists already, it returns (-1 - ordinal).
      */
-    public long find(BytesRef key, int code) {
-        final long slot = slot(rehash(code), mask);
-        for (long index = slot;; index = nextSlot(index, mask)) {
-            final long id = id(index);
-            if (id == -1L || key.bytesEquals(get(id, spare))) {
-                return id;
+    public long add(final BytesRef key) {
+        final long hash = hasher.hash(key);
+        final long fingerprint = hash & MASK_FINGERPRINT;
+
+        for (long idx = hash & mask, value, ordinal;; idx = (idx + 1) & mask) {
+            if ((value = table.get(idx)) == -1) {
+                final long val = fingerprint | size;
+                if (size >= grow) {
+                    growAndInsert(hash, val);
+                } else {
+                    table.set(idx, val);
+                }
+                return append(key, hash);
+            } else if (((value & MASK_FINGERPRINT) == fingerprint) && key.bytesEquals(get(ordinal = (value & MASK_ORDINAL), scratch))) {
+                return -1 - ordinal;
             }
         }
     }
 
-    /** Sugar for {@link #find(BytesRef, int) find(key, key.hashCode()} */
-    public long find(BytesRef key) {
-        return find(key, key.hashCode());
-    }
+    /**
+     * Returns the ordinal associated with the given key, or -1 if the key doesn't exist.
+     *
+     * <p>
+     * Using the 64-bit hash value, up to 32 least significant bits (LSB) are used to identify the
+     * home slot in the hash table, and an additional 32 bits are used to identify the fingerprint.
+     * The fingerprint further increases the entropy and reduces the number of false lookups in the
+     * keys' table during equality checks, which is expensive.
+     *
+     * <p>
+     * Total entropy bits = 32 + log2(capacity)
+     *
+     * <p>
+     * Linear probing starts from the home slot, until a match or an empty slot is found.
+     * Values are first checked using their fingerprint (to reduce false positives), then verified
+     * in the keys' table using an equality check.
+     */
+    public long find(final BytesRef key) {
+        final long hash = hasher.hash(key);
+        final long fingerprint = hash & MASK_FINGERPRINT;
 
-    private long set(BytesRef key, int code, long id) {
-        assert rehash(key.hashCode()) == code;
-        assert size < maxSize;
-        final long slot = slot(code, mask);
-        for (long index = slot;; index = nextSlot(index, mask)) {
-            final long curId = id(index);
-            if (curId == -1) { // means unset
-                id(index, id);
-                append(id, key, code);
-                ++size;
-                return id;
-            } else if (key.bytesEquals(get(curId, spare))) {
-                return -1 - curId;
+        for (long idx = hash & mask, value, ordinal;; idx = (idx + 1) & mask) {
+            if ((value = table.get(idx)) == -1) {
+                return -1;
+            } else if (((value & MASK_FINGERPRINT) == fingerprint) && key.bytesEquals(get(ordinal = (value & MASK_ORDINAL), scratch))) {
+                return ordinal;
             }
         }
     }
 
-    private void append(long id, BytesRef key, int code) {
-        assert size == id;
-        final long startOffset = startOffsets.get(size);
-        bytes = bigArrays.grow(bytes, startOffset + key.length);
-        bytes.set(startOffset, key.bytes, key.offset, key.length);
-        startOffsets = bigArrays.grow(startOffsets, size + 2);
-        startOffsets.set(size + 1, startOffset + key.length);
-        hashes = bigArrays.grow(hashes, id + 1);
-        hashes.set(id, code);
+    /**
+     * Returns the key associated with the given ordinal.
+     * The result is undefined for an unused ordinal.
+     *
+     * <p>
+     * Beware that the content of the {@link BytesRef} may become invalid as soon as {@link #close()} is called
+     */
+    public BytesRef get(final long ordinal, final BytesRef dest) {
+        final long start = offsets.get(ordinal);
+        final int length = (int) (offsets.get(ordinal + 1) - start);
+        keys.get(start, length, dest);
+        return dest;
     }
 
-    private boolean assertConsistent(long id, int code) {
-        get(id, spare);
-        return rehash(spare.hashCode()) == code;
+    /**
+     * Returns the number of mappings in this hash table.
+     */
+    public long size() {
+        return size;
     }
 
-    private void reset(int code, long id) {
-        assert assertConsistent(id, code);
-        final long slot = slot(code, mask);
-        for (long index = slot;; index = nextSlot(index, mask)) {
-            final long curId = id(index);
-            if (curId == -1) { // means unset
-                id(index, id);
-                break;
-            }
-        }
+    /**
+     * Appends the key in the keys' and offsets' tables.
+     */
+    private long append(final BytesRef key, final long hash) {
+        final long start = offsets.get(size);
+        final long end = start + key.length;
+        offsets = bigArrays.grow(offsets, size + 2);
+        offsets.set(size + 1, end);
+        keys = bigArrays.grow(keys, end);
+        keys.set(start, key.bytes, key.offset, key.length);
+        hashes = bigArrays.grow(hashes, size + 1);
+        hashes.set(size, hash);
+        return size++;
     }
 
     /**
-     * Try to add <code>key</code>. Return its newly allocated id if it wasn't in the hash table yet, or <code>-1-id</code>
-     * if it was already present in the hash table.
+     * Grows the hash table by doubling its capacity, inserting the provided value,
+     * and reinserting the previous values at their updated slots.
      */
-    public long add(BytesRef key, int code) {
-        if (size >= maxSize) {
-            assert size == maxSize;
-            grow();
-        }
-        assert size < maxSize;
-        return set(key, rehash(code), size);
-    }
+    private void growAndInsert(final long hash, final long value) {
+        // Ensure that the hash table doesn't grow too large.
+        // This implicitly also ensures that the ordinals are no larger than 2^32, thus,
+        // preventing them from polluting the fingerprint bits in the hash table values.
+        assert capacity < MAX_CAPACITY : "hash table already at the max capacity";
+
+        capacity <<= 1;
+        mask = capacity - 1;
+        grow = (long) (capacity * loadFactor);
+        table = bigArrays.grow(table, capacity);
+        table.fill(0, capacity, -1);
+        table.set(hash & mask, value);
 
-    /** Sugar to {@link #add(BytesRef, int) add(key, key.hashCode()}. */
-    public long add(BytesRef key) {
-        return add(key, key.hashCode());
+        for (long ordinal = 0; ordinal < size; ordinal++) {
+            reinsert(ordinal, hashes.get(ordinal));
+        }
     }
 
-    @Override
-    protected void removeAndAdd(long index) {
-        final long id = id(index, -1);
-        assert id >= 0;
-        final int code = hashes.get(id);
-        reset(code, id);
+    /**
+     * Reinserts the hash table value for an existing key stored at the given ordinal.
+     */
+    private void reinsert(final long ordinal, final long hash) {
+        for (long idx = hash & mask;; idx = (idx + 1) & mask) {
+            if (table.get(idx) == -1) {
+                table.set(idx, (hash & MASK_FINGERPRINT) | ordinal);
+                return;
+            }
+        }
     }
 
     @Override
     public void close() {
-        try (Releasable releasable = Releasables.wrap(bytes, hashes, startOffsets)) {
-            super.close();
-        }
+        Releasables.close(table, offsets, keys, hashes);
     }
 
+    /**
+     * Hasher calculates the hash of a {@link BytesRef} key.
+     */
+    @FunctionalInterface
+    public interface Hasher {
+        long hash(BytesRef key);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/util/CachedSupplier.java b/server/src/main/java/org/opensearch/common/util/CachedSupplier.java
index 647ef46f7a890..f81e57d9fbad6 100644
--- a/server/src/main/java/org/opensearch/common/util/CachedSupplier.java
+++ b/server/src/main/java/org/opensearch/common/util/CachedSupplier.java
@@ -38,6 +38,8 @@
  * A {@link Supplier} that caches its return value. This may be useful to make
  * a {@link Supplier} idempotent or for performance reasons if always returning
  * the same instance is acceptable.
+ *
+ * @opensearch.internal
  */
 public final class CachedSupplier<T> implements Supplier<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/CancellableThreads.java b/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
index f9cb8cc2d60f5..8bc3ca3affb12 100644
--- a/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
+++ b/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
@@ -31,11 +31,11 @@
 
 package org.opensearch.common.util;
 
-import org.apache.lucene.util.SetOnce;
 import org.apache.lucene.util.ThreadInterruptedException;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.HashSet;
@@ -47,6 +47,8 @@
  * of cancellation.
  *
  * Cancellation policy: This class does not support external interruption via <code>Thread#interrupt()</code>. Always use #cancel() instead.
+ *
+ * @opensearch.internal
  */
 public class CancellableThreads {
     private final Set<Thread> threads = new HashSet<>();
@@ -178,14 +180,29 @@ public synchronized void cancel(String reason) {
         threads.clear();
     }
 
+    /**
+     * Interruptible interface
+     *
+     * @opensearch.internal
+     */
     public interface Interruptible extends IOInterruptible {
         void run() throws InterruptedException;
     }
 
+    /**
+     * IO Interruptible
+     *
+     * @opensearch.internal
+     */
     public interface IOInterruptible {
         void run() throws IOException, InterruptedException;
     }
 
+    /**
+     * Thrown if there is an error cancelling execution
+     *
+     * @opensearch.internal
+     */
     public static class ExecutionCancelledException extends OpenSearchException {
 
         public ExecutionCancelledException(String msg) {
@@ -204,6 +221,11 @@ public synchronized void setOnCancel(OnCancel onCancel) {
         this.onCancel.set(onCancel);
     }
 
+    /**
+     * Called when a thread is cancelled
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface OnCancel {
         /**
diff --git a/server/src/main/java/org/opensearch/common/util/CollectionUtils.java b/server/src/main/java/org/opensearch/common/util/CollectionUtils.java
deleted file mode 100644
index 7817e7b29df9a..0000000000000
--- a/server/src/main/java/org/opensearch/common/util/CollectionUtils.java
+++ /dev/null
@@ -1,378 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.util;
-
-import com.carrotsearch.hppc.ObjectArrayList;
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.BytesRefArray;
-import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.InPlaceMergeSorter;
-import org.apache.lucene.util.IntroSorter;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.Iterators;
-
-import java.nio.file.Path;
-import java.util.AbstractList;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.IdentityHashMap;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import java.util.Objects;
-import java.util.RandomAccess;
-import java.util.Set;
-
-/** Collections-related utility methods. */
-public class CollectionUtils {
-
-    /**
-     * Checks if the given array contains any elements.
-     *
-     * @param array The array to check
-     *
-     * @return false if the array contains an element, true if not or the array is null.
-     */
-    public static boolean isEmpty(Object[] array) {
-        return array == null || array.length == 0;
-    }
-
-    /**
-     * Return a rotated view of the given list with the given distance.
-     */
-    public static <T> List<T> rotate(final List<T> list, int distance) {
-        if (list.isEmpty()) {
-            return list;
-        }
-
-        int d = distance % list.size();
-        if (d < 0) {
-            d += list.size();
-        }
-
-        if (d == 0) {
-            return list;
-        }
-
-        return new RotatedList<>(list, d);
-    }
-
-    public static void sortAndDedup(final ObjectArrayList<byte[]> array) {
-        int len = array.size();
-        if (len > 1) {
-            sort(array);
-            int uniqueCount = 1;
-            for (int i = 1; i < len; ++i) {
-                if (!Arrays.equals(array.get(i), array.get(i - 1))) {
-                    array.set(uniqueCount++, array.get(i));
-                }
-            }
-            array.elementsCount = uniqueCount;
-        }
-    }
-
-    public static void sort(final ObjectArrayList<byte[]> array) {
-        new IntroSorter() {
-
-            byte[] pivot;
-
-            @Override
-            protected void swap(int i, int j) {
-                final byte[] tmp = array.get(i);
-                array.set(i, array.get(j));
-                array.set(j, tmp);
-            }
-
-            @Override
-            protected int compare(int i, int j) {
-                return compare(array.get(i), array.get(j));
-            }
-
-            @Override
-            protected void setPivot(int i) {
-                pivot = array.get(i);
-            }
-
-            @Override
-            protected int comparePivot(int j) {
-                return compare(pivot, array.get(j));
-            }
-
-            private int compare(byte[] left, byte[] right) {
-                for (int i = 0, j = 0; i < left.length && j < right.length; i++, j++) {
-                    int a = left[i] & 0xFF;
-                    int b = right[j] & 0xFF;
-                    if (a != b) {
-                        return a - b;
-                    }
-                }
-                return left.length - right.length;
-            }
-
-        }.sort(0, array.size());
-    }
-
-    public static int[] toArray(Collection<Integer> ints) {
-        Objects.requireNonNull(ints);
-        return ints.stream().mapToInt(s -> s).toArray();
-    }
-
-    /**
-     * Deeply inspects a Map, Iterable, or Object array looking for references back to itself.
-     * @throws IllegalArgumentException if a self-reference is found
-     * @param value The object to evaluate looking for self references
-     * @param messageHint A string to be included in the exception message if the call fails, to provide
-     *                    more context to the handler of the exception
-     */
-    public static void ensureNoSelfReferences(Object value, String messageHint) {
-        Iterable<?> it = convert(value);
-        if (it != null) {
-            ensureNoSelfReferences(it, value, Collections.newSetFromMap(new IdentityHashMap<>()), messageHint);
-        }
-    }
-
-    private static Iterable<?> convert(Object value) {
-        if (value == null) {
-            return null;
-        }
-        if (value instanceof Map) {
-            Map<?, ?> map = (Map<?, ?>) value;
-            return () -> Iterators.concat(map.keySet().iterator(), map.values().iterator());
-        } else if ((value instanceof Iterable) && (value instanceof Path == false)) {
-            return (Iterable<?>) value;
-        } else if (value instanceof Object[]) {
-            return Arrays.asList((Object[]) value);
-        } else {
-            return null;
-        }
-    }
-
-    private static void ensureNoSelfReferences(
-        final Iterable<?> value,
-        Object originalReference,
-        final Set<Object> ancestors,
-        String messageHint
-    ) {
-        if (value != null) {
-            if (ancestors.add(originalReference) == false) {
-                String suffix = Strings.isNullOrEmpty(messageHint) ? "" : String.format(Locale.ROOT, " (%s)", messageHint);
-                throw new IllegalArgumentException("Iterable object is self-referencing itself" + suffix);
-            }
-            for (Object o : value) {
-                ensureNoSelfReferences(convert(o), o, ancestors, messageHint);
-            }
-            ancestors.remove(originalReference);
-        }
-    }
-
-    /**
-     * Returns an unmodifiable copy of the given map.
-     * @param map Map to copy
-     * @return unmodifiable copy of the map
-     */
-    public static <R, T> Map<R, T> copyMap(Map<R, T> map) {
-        if (map.isEmpty()) {
-            return Collections.emptyMap();
-        } else {
-            return Collections.unmodifiableMap(new HashMap<>(map));
-        }
-    }
-
-    private static class RotatedList<T> extends AbstractList<T> implements RandomAccess {
-
-        private final List<T> in;
-        private final int distance;
-
-        RotatedList(List<T> list, int distance) {
-            if (distance < 0 || distance >= list.size()) {
-                throw new IllegalArgumentException();
-            }
-            if (!(list instanceof RandomAccess)) {
-                throw new IllegalArgumentException();
-            }
-            this.in = list;
-            this.distance = distance;
-        }
-
-        @Override
-        public T get(int index) {
-            int idx = distance + index;
-            if (idx < 0 || idx >= in.size()) {
-                idx -= in.size();
-            }
-            return in.get(idx);
-        }
-
-        @Override
-        public int size() {
-            return in.size();
-        }
-    }
-
-    public static void sort(final BytesRefArray bytes, final int[] indices) {
-        sort(new BytesRefBuilder(), new BytesRefBuilder(), bytes, indices);
-    }
-
-    private static void sort(
-        final BytesRefBuilder scratch,
-        final BytesRefBuilder scratch1,
-        final BytesRefArray bytes,
-        final int[] indices
-    ) {
-
-        final int numValues = bytes.size();
-        assert indices.length >= numValues;
-        if (numValues > 1) {
-            new InPlaceMergeSorter() {
-                final Comparator<BytesRef> comparator = Comparator.naturalOrder();
-
-                @Override
-                protected int compare(int i, int j) {
-                    return comparator.compare(bytes.get(scratch, indices[i]), bytes.get(scratch1, indices[j]));
-                }
-
-                @Override
-                protected void swap(int i, int j) {
-                    int value_i = indices[i];
-                    indices[i] = indices[j];
-                    indices[j] = value_i;
-                }
-            }.sort(0, numValues);
-        }
-
-    }
-
-    public static int sortAndDedup(final BytesRefArray bytes, final int[] indices) {
-        final BytesRefBuilder scratch = new BytesRefBuilder();
-        final BytesRefBuilder scratch1 = new BytesRefBuilder();
-        final int numValues = bytes.size();
-        assert indices.length >= numValues;
-        if (numValues <= 1) {
-            return numValues;
-        }
-        sort(scratch, scratch1, bytes, indices);
-        int uniqueCount = 1;
-        BytesRefBuilder previous = scratch;
-        BytesRefBuilder current = scratch1;
-        bytes.get(previous, indices[0]);
-        for (int i = 1; i < numValues; ++i) {
-            bytes.get(current, indices[i]);
-            if (!previous.get().equals(current.get())) {
-                indices[uniqueCount++] = indices[i];
-            }
-            BytesRefBuilder tmp = previous;
-            previous = current;
-            current = tmp;
-        }
-        return uniqueCount;
-
-    }
-
-    public static <E> ArrayList<E> iterableAsArrayList(Iterable<? extends E> elements) {
-        if (elements == null) {
-            throw new NullPointerException("elements");
-        }
-        if (elements instanceof Collection) {
-            return new ArrayList<>((Collection) elements);
-        } else {
-            ArrayList<E> list = new ArrayList<>();
-            for (E element : elements) {
-                list.add(element);
-            }
-            return list;
-        }
-    }
-
-    public static <E> ArrayList<E> arrayAsArrayList(E... elements) {
-        if (elements == null) {
-            throw new NullPointerException("elements");
-        }
-        return new ArrayList<>(Arrays.asList(elements));
-    }
-
-    public static <E> ArrayList<E> asArrayList(E first, E... other) {
-        if (other == null) {
-            throw new NullPointerException("other");
-        }
-        ArrayList<E> list = new ArrayList<>(1 + other.length);
-        list.add(first);
-        list.addAll(Arrays.asList(other));
-        return list;
-    }
-
-    public static <E> ArrayList<E> asArrayList(E first, E second, E... other) {
-        if (other == null) {
-            throw new NullPointerException("other");
-        }
-        ArrayList<E> list = new ArrayList<>(1 + 1 + other.length);
-        list.add(first);
-        list.add(second);
-        list.addAll(Arrays.asList(other));
-        return list;
-    }
-
-    public static <E> ArrayList<E> newSingletonArrayList(E element) {
-        return new ArrayList<>(Collections.singletonList(element));
-    }
-
-    public static <E> List<List<E>> eagerPartition(List<E> list, int size) {
-        if (list == null) {
-            throw new NullPointerException("list");
-        }
-        if (size <= 0) {
-            throw new IllegalArgumentException("size <= 0");
-        }
-        List<List<E>> result = new ArrayList<>((int) Math.ceil(list.size() / size));
-
-        List<E> accumulator = new ArrayList<>(size);
-        int count = 0;
-        for (E element : list) {
-            if (count == size) {
-                result.add(accumulator);
-                accumulator = new ArrayList<>(size);
-                count = 0;
-            }
-            accumulator.add(element);
-            count++;
-        }
-        if (count > 0) {
-            result.add(accumulator);
-        }
-
-        return result;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/common/util/CombinedRateLimiter.java b/server/src/main/java/org/opensearch/common/util/CombinedRateLimiter.java
index 6fe67d378c273..eac5749494219 100644
--- a/server/src/main/java/org/opensearch/common/util/CombinedRateLimiter.java
+++ b/server/src/main/java/org/opensearch/common/util/CombinedRateLimiter.java
@@ -33,12 +33,14 @@
 package org.opensearch.common.util;
 
 import org.apache.lucene.store.RateLimiter;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * A rate limiter designed for multiple concurrent users.
+ *
+ * @opensearch.internal
  */
 public class CombinedRateLimiter {
 
diff --git a/server/src/main/java/org/opensearch/common/util/Comparators.java b/server/src/main/java/org/opensearch/common/util/Comparators.java
index 9a5f8d1849e8d..39e57dc5d16ab 100644
--- a/server/src/main/java/org/opensearch/common/util/Comparators.java
+++ b/server/src/main/java/org/opensearch/common/util/Comparators.java
@@ -36,6 +36,8 @@
 
 /**
  * {@link Comparator}-related utility methods.
+ *
+ * @opensearch.internal
  */
 public enum Comparators {
     ;
diff --git a/server/src/main/java/org/opensearch/common/util/Countable.java b/server/src/main/java/org/opensearch/common/util/Countable.java
index ee354421a8633..1adf6d2fb015c 100644
--- a/server/src/main/java/org/opensearch/common/util/Countable.java
+++ b/server/src/main/java/org/opensearch/common/util/Countable.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.common.util;
 
+/**
+ * Base countable interface.
+ *
+ * @opensearch.internal
+ */
 public interface Countable {
     int size();
 }
diff --git a/server/src/main/java/org/opensearch/common/util/CuckooFilter.java b/server/src/main/java/org/opensearch/common/util/CuckooFilter.java
index e23b21936dfe3..0c792b37ccfa9 100644
--- a/server/src/main/java/org/opensearch/common/util/CuckooFilter.java
+++ b/server/src/main/java/org/opensearch/common/util/CuckooFilter.java
@@ -35,9 +35,9 @@
 import org.apache.lucene.store.DataOutput;
 import org.apache.lucene.util.packed.PackedInts;
 import org.apache.lucene.util.packed.XPackedInts;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Iterator;
@@ -74,6 +74,8 @@
  * Proceedings of the 10th ACM International on Conference on emerging Networking Experiments and Technologies. ACM, 2014.
  *
  * https://www.cs.cmu.edu/~dga/papers/cuckoo-conext2014.pdf
+ *
+ * @opensearch.internal
  */
 public class CuckooFilter implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/DoubleArray.java b/server/src/main/java/org/opensearch/common/util/DoubleArray.java
index f047882c842a5..ae66902f6f795 100644
--- a/server/src/main/java/org/opensearch/common/util/DoubleArray.java
+++ b/server/src/main/java/org/opensearch/common/util/DoubleArray.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
+import org.opensearch.core.common.util.BigArray;
+
 /**
  * Abstraction of an array of double values.
+ *
+ * @opensearch.internal
  */
 public interface DoubleArray extends BigArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/FeatureFlags.java b/server/src/main/java/org/opensearch/common/util/FeatureFlags.java
new file mode 100644
index 0000000000000..b89d2d0549823
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/FeatureFlags.java
@@ -0,0 +1,103 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
+
+/**
+ * Utility class to manage feature flags. Feature flags are system properties that must be set on the JVM.
+ * These are used to gate the visibility/availability of incomplete features. Fore more information, see
+ * https://featureflags.io/feature-flag-introduction/
+ *
+ * @opensearch.internal
+ */
+public class FeatureFlags {
+    /**
+     * Gates the visibility of the segment replication experimental features that allows users to test unreleased beta features.
+     */
+    public static final String SEGMENT_REPLICATION_EXPERIMENTAL =
+        "opensearch.experimental.feature.segment_replication_experimental.enabled";
+
+    /**
+     * Gates the ability for Searchable Snapshots to read snapshots that are older than the
+     * guaranteed backward compatibility for OpenSearch (one prior major version) on a best effort basis.
+     */
+    public static final String SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY =
+        "opensearch.experimental.feature.searchable_snapshot.extended_compatibility.enabled";
+
+    /**
+     * Gates the functionality of extensions.
+     * Once the feature is ready for production release, this feature flag can be removed.
+     */
+    public static final String EXTENSIONS = "opensearch.experimental.feature.extensions.enabled";
+
+    /**
+     * Gates the functionality of identity.
+     */
+    public static final String IDENTITY = "opensearch.experimental.feature.identity.enabled";
+
+    /**
+     * Gates the functionality of concurrently searching the segments
+     * Once the feature is ready for release, this feature flag can be removed.
+     */
+    public static final String CONCURRENT_SEGMENT_SEARCH = "opensearch.experimental.feature.concurrent_segment_search.enabled";
+
+    /**
+     * Gates the functionality of telemetry framework.
+     */
+    public static final String TELEMETRY = "opensearch.experimental.feature.telemetry.enabled";
+
+    /**
+     * Should store the settings from opensearch.yml.
+     */
+    private static Settings settings;
+
+    /**
+     * This method is responsible to map settings from opensearch.yml to local stored
+     * settings value. That is used for the existing isEnabled method.
+     *
+     * @param openSearchSettings The settings stored in opensearch.yml.
+     */
+    public static void initializeFeatureFlags(Settings openSearchSettings) {
+        settings = openSearchSettings;
+    }
+
+    /**
+     * Used to test feature flags whose values are expected to be booleans.
+     * This method returns true if the value is "true" (case-insensitive),
+     * and false otherwise.
+     */
+    public static boolean isEnabled(String featureFlagName) {
+        if ("true".equalsIgnoreCase(System.getProperty(featureFlagName))) {
+            // TODO: Remove the if condition once FeatureFlags are only supported via opensearch.yml
+            return true;
+        }
+        return settings != null && settings.getAsBoolean(featureFlagName, false);
+    }
+
+    public static final Setting<Boolean> SEGMENT_REPLICATION_EXPERIMENTAL_SETTING = Setting.boolSetting(
+        SEGMENT_REPLICATION_EXPERIMENTAL,
+        false,
+        Property.NodeScope
+    );
+
+    public static final Setting<Boolean> EXTENSIONS_SETTING = Setting.boolSetting(EXTENSIONS, false, Property.NodeScope);
+
+    public static final Setting<Boolean> IDENTITY_SETTING = Setting.boolSetting(IDENTITY, false, Property.NodeScope);
+
+    public static final Setting<Boolean> TELEMETRY_SETTING = Setting.boolSetting(TELEMETRY, false, Property.NodeScope);
+
+    public static final Setting<Boolean> CONCURRENT_SEGMENT_SEARCH_SETTING = Setting.boolSetting(
+        CONCURRENT_SEGMENT_SEARCH,
+        false,
+        Property.NodeScope
+    );
+}
diff --git a/server/src/main/java/org/opensearch/common/util/FloatArray.java b/server/src/main/java/org/opensearch/common/util/FloatArray.java
index f1744fef83199..81f6bebb7508c 100644
--- a/server/src/main/java/org/opensearch/common/util/FloatArray.java
+++ b/server/src/main/java/org/opensearch/common/util/FloatArray.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
+import org.opensearch.core.common.util.BigArray;
+
 /**
  * Abstraction of an array of double values.
+ *
+ * @opensearch.internal
  */
 public interface FloatArray extends BigArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/IntArray.java b/server/src/main/java/org/opensearch/common/util/IntArray.java
index 0beb5e12134ad..eb43e013f3758 100644
--- a/server/src/main/java/org/opensearch/common/util/IntArray.java
+++ b/server/src/main/java/org/opensearch/common/util/IntArray.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
+import org.opensearch.core.common.util.BigArray;
+
 /**
  * Abstraction of an array of integer values.
+ *
+ * @opensearch.internal
  */
 public interface IntArray extends BigArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/LazyInitializable.java b/server/src/main/java/org/opensearch/common/util/LazyInitializable.java
index e302f22bd0aaa..98192796fb920 100644
--- a/server/src/main/java/org/opensearch/common/util/LazyInitializable.java
+++ b/server/src/main/java/org/opensearch/common/util/LazyInitializable.java
@@ -46,6 +46,8 @@
  * {@link Consumer}. On {@code #reset()} the value will be passed to the
  * <code>onReset</code> {@code Consumer} and the next {@code #getOrCompute()}
  * will regenerate the value.
+ *
+ * @opensearch.internal
  */
 public final class LazyInitializable<T, E extends Exception> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/LocaleUtils.java b/server/src/main/java/org/opensearch/common/util/LocaleUtils.java
index 47617d198b6b6..c684b1b2d781f 100644
--- a/server/src/main/java/org/opensearch/common/util/LocaleUtils.java
+++ b/server/src/main/java/org/opensearch/common/util/LocaleUtils.java
@@ -38,6 +38,8 @@
 
 /**
  * Utilities for for dealing with {@link Locale} objects
+ *
+ * @opensearch.internal
  */
 public class LocaleUtils {
 
diff --git a/server/src/main/java/org/opensearch/common/util/LongArray.java b/server/src/main/java/org/opensearch/common/util/LongArray.java
index e88c27cb0e856..0c32effd04cdc 100644
--- a/server/src/main/java/org/opensearch/common/util/LongArray.java
+++ b/server/src/main/java/org/opensearch/common/util/LongArray.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
+import org.opensearch.core.common.util.BigArray;
+
 /**
  * Abstraction of an array of long values.
+ *
+ * @opensearch.internal
  */
 public interface LongArray extends BigArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/LongHash.java b/server/src/main/java/org/opensearch/common/util/LongHash.java
index 079577b1530a7..71272e79c65b3 100644
--- a/server/src/main/java/org/opensearch/common/util/LongHash.java
+++ b/server/src/main/java/org/opensearch/common/util/LongHash.java
@@ -40,6 +40,8 @@
  * probing, growth is smooth thanks to {@link BigArrays} and capacity is always
  * a multiple of 2 for faster identification of buckets.
  * This class is not thread-safe.
+ *
+ * @opensearch.internal
  */
 // IDs are internally stored as id + 1 so that 0 encodes for an empty slot
 public final class LongHash extends AbstractHash {
diff --git a/server/src/main/java/org/opensearch/common/util/LongLongHash.java b/server/src/main/java/org/opensearch/common/util/LongLongHash.java
index 33777ecc89fb6..f1cdd29932b2f 100644
--- a/server/src/main/java/org/opensearch/common/util/LongLongHash.java
+++ b/server/src/main/java/org/opensearch/common/util/LongLongHash.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.BitMixer;
-
 import org.opensearch.common.lease.Releasables;
 
 /**
@@ -42,6 +40,8 @@
  * linear probing, growth is smooth thanks to {@link BigArrays} and capacity
  * is always a multiple of 2 for faster identification of buckets.
  * This class is not thread-safe.
+ *
+ * @opensearch.internal
  */
 // IDs are internally stored as id + 1 so that 0 encodes for an empty slot
 public final class LongLongHash extends AbstractHash {
diff --git a/server/src/main/java/org/opensearch/common/util/LongObjectPagedHashMap.java b/server/src/main/java/org/opensearch/common/util/LongObjectPagedHashMap.java
index 9abd0c9d46682..9d654e96779bf 100644
--- a/server/src/main/java/org/opensearch/common/util/LongObjectPagedHashMap.java
+++ b/server/src/main/java/org/opensearch/common/util/LongObjectPagedHashMap.java
@@ -40,6 +40,8 @@
 /**
  * A hash table from native longs to objects. This implementation resolves collisions
  * using open-addressing and does not support null values. This class is not thread-safe.
+ *
+ * @opensearch.internal
  */
 public class LongObjectPagedHashMap<T> extends AbstractPagedHashMap implements Iterable<LongObjectPagedHashMap.Cursor<T>> {
 
@@ -200,6 +202,11 @@ protected void removeAndAdd(long index) {
         assert removed == null;
     }
 
+    /**
+     * Cursor for the map
+     *
+     * @opensearch.internal
+     */
     public static final class Cursor<T> {
         public long index;
         public long key;
diff --git a/server/src/main/java/org/opensearch/common/util/Maps.java b/server/src/main/java/org/opensearch/common/util/Maps.java
index db99ec29d3a2d..08ee2375d1f94 100644
--- a/server/src/main/java/org/opensearch/common/util/Maps.java
+++ b/server/src/main/java/org/opensearch/common/util/Maps.java
@@ -35,6 +35,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Map utility class.
+ *
+ * @opensearch.internal
+ */
 public class Maps {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/util/MovingAverage.java b/server/src/main/java/org/opensearch/common/util/MovingAverage.java
new file mode 100644
index 0000000000000..50d863709d489
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/MovingAverage.java
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+/**
+ * MovingAverage is used to calculate the moving average of last 'n' observations.
+ *
+ * @opensearch.internal
+ */
+public class MovingAverage {
+    private final int windowSize;
+    private final long[] observations;
+
+    private volatile long count = 0;
+    private volatile long sum = 0;
+    private volatile double average = 0;
+
+    public MovingAverage(int windowSize) {
+        checkWindowSize(windowSize);
+        this.windowSize = windowSize;
+        this.observations = new long[windowSize];
+    }
+
+    /**
+     * Used for changing the window size of {@code MovingAverage}.
+     *
+     * @param newWindowSize new window size.
+     * @return copy of original object with updated size.
+     */
+    public MovingAverage copyWithSize(int newWindowSize) {
+        MovingAverage copy = new MovingAverage(newWindowSize);
+        // Start is inclusive, but end is exclusive
+        long start, end = count;
+        if (isReady() == false) {
+            start = 0;
+        } else {
+            start = end - windowSize;
+        }
+        // If the newWindow Size is smaller than the elements eligible to be copied over, then we adjust the start value
+        if (end - start > newWindowSize) {
+            start = end - newWindowSize;
+        }
+        for (int i = (int) start; i < end; i++) {
+            copy.record(observations[i % observations.length]);
+        }
+        return copy;
+    }
+
+    private void checkWindowSize(int size) {
+        if (size <= 0) {
+            throw new IllegalArgumentException("window size must be greater than zero");
+        }
+    }
+
+    /**
+     * Records a new observation and evicts the n-th last observation.
+     */
+    public synchronized double record(long value) {
+        long delta = value - observations[(int) (count % observations.length)];
+        observations[(int) (count % observations.length)] = value;
+
+        count++;
+        sum += delta;
+        average = (double) sum / Math.min(count, observations.length);
+        return average;
+    }
+
+    public double getAverage() {
+        return average;
+    }
+
+    public long getCount() {
+        return count;
+    }
+
+    public boolean isReady() {
+        return count >= windowSize;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/util/ObjectArray.java b/server/src/main/java/org/opensearch/common/util/ObjectArray.java
index 7663c53bb5175..9c882742b56ab 100644
--- a/server/src/main/java/org/opensearch/common/util/ObjectArray.java
+++ b/server/src/main/java/org/opensearch/common/util/ObjectArray.java
@@ -32,8 +32,12 @@
 
 package org.opensearch.common.util;
 
+import org.opensearch.core.common.util.BigArray;
+
 /**
  * Abstraction of an array of object values.
+ *
+ * @opensearch.internal
  */
 public interface ObjectArray<T> extends BigArray {
 
diff --git a/server/src/main/java/org/opensearch/common/util/PageCacheRecycler.java b/server/src/main/java/org/opensearch/common/util/PageCacheRecycler.java
index ae9555902c395..b6fd385d25082 100644
--- a/server/src/main/java/org/opensearch/common/util/PageCacheRecycler.java
+++ b/server/src/main/java/org/opensearch/common/util/PageCacheRecycler.java
@@ -38,8 +38,9 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.bytes.PagedBytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.Arrays;
 import java.util.Locale;
@@ -49,7 +50,11 @@
 import static org.opensearch.common.recycler.Recyclers.dequeFactory;
 import static org.opensearch.common.recycler.Recyclers.none;
 
-/** A recycler of fixed-size pages. */
+/**
+ * A recycler of fixed-size pages.
+ *
+ * @opensearch.internal
+ */
 public class PageCacheRecycler {
 
     public static final Setting<Type> TYPE_SETTING = new Setting<>(
@@ -90,7 +95,7 @@ public class PageCacheRecycler {
     );
 
     /** Page size in bytes: 16KB */
-    public static final int PAGE_SIZE_IN_BYTES = 1 << 14;
+    public static final int PAGE_SIZE_IN_BYTES = PagedBytesReference.PAGE_SIZE_IN_BYTES;
     public static final int OBJECT_PAGE_SIZE = PAGE_SIZE_IN_BYTES / RamUsageEstimator.NUM_BYTES_OBJECT_REF;
     public static final int LONG_PAGE_SIZE = PAGE_SIZE_IN_BYTES / Long.BYTES;
     public static final int INT_PAGE_SIZE = PAGE_SIZE_IN_BYTES / Integer.BYTES;
@@ -227,6 +232,11 @@ private static <T> Recycler<T> build(Type type, int limit, int availableProcesso
         return recycler;
     }
 
+    /**
+     * Type of the page cache recycler
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         QUEUE {
             @Override
diff --git a/server/src/main/java/org/opensearch/common/util/PlainIterator.java b/server/src/main/java/org/opensearch/common/util/PlainIterator.java
index a84e8a064804d..fff8126f13e5d 100644
--- a/server/src/main/java/org/opensearch/common/util/PlainIterator.java
+++ b/server/src/main/java/org/opensearch/common/util/PlainIterator.java
@@ -36,6 +36,11 @@
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * A plain iterator
+ *
+ * @opensearch.internal
+ */
 public class PlainIterator<T> implements Iterable<T>, Countable {
     private final List<T> elements;
 
diff --git a/server/src/main/java/org/opensearch/common/util/ReorganizingLongHash.java b/server/src/main/java/org/opensearch/common/util/ReorganizingLongHash.java
new file mode 100644
index 0000000000000..86e7227cb6c85
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/ReorganizingLongHash.java
@@ -0,0 +1,306 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.common.Numbers;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lease.Releasables;
+
+/**
+ * Specialized hash table implementation that maps a (primitive) long to long.
+ *
+ * <p>
+ * It organizes itself by moving keys around dynamically in order to reduce the
+ * longest probe sequence length (PSL), which makes lookups faster as keys are likely to
+ * be found in the same CPU cache line. It also optimizes lookups for recently added keys,
+ * making it useful for aggregations where keys are correlated across consecutive hits.
+ *
+ * <p>
+ * This class is not thread-safe.
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class ReorganizingLongHash implements Releasable {
+    private static final long MAX_CAPACITY = 1L << 32;
+    private static final long DEFAULT_INITIAL_CAPACITY = 32;
+    private static final float DEFAULT_LOAD_FACTOR = 0.6f;
+
+    /**
+     * Maximum load factor after which the capacity is doubled.
+     */
+    private final float loadFactor;
+
+    /**
+     * Utility class to allocate recyclable arrays.
+     */
+    private final BigArrays bigArrays;
+
+    /**
+     * Current capacity of the hash table. This must be a power of two so that the hash table slot
+     * can be identified quickly using bitmasks, thus avoiding expensive modulo or integer division.
+     */
+    private long capacity;
+
+    /**
+     * Bitmask to identify the hash table slot from a key's hash.
+     */
+    private long mask;
+
+    /**
+     * Size threshold after which the hash table needs to be doubled in capacity.
+     */
+    private long grow;
+
+    /**
+     * Current size of the hash table.
+     */
+    private long size;
+
+    /**
+     * Underlying array to store the hash table values.
+     *
+     * <p>
+     * Each hash table value (64-bit) uses the following byte packing strategy:
+     * <pre>
+     * |=========|===============|================|================================|
+     * | Discard | PSL           | Fingerprint    | Ordinal                        |
+     * |    -    |---------------|----------------|--------------------------------|
+     * | 1 bit   | 15 bits       | 16 bits        | 32 bits                        |
+     * |=========|===============|================|================================|
+     * </pre>
+     *
+     * <p>
+     * This allows us to encode and manipulate additional information in the hash table
+     * itself without having to look elsewhere in the memory, which is much slower.
+     *
+     * <p>
+     * Terminology: <code>table[index] = value = (discard | psl | fingerprint | ordinal)</code>
+     */
+    private LongArray table;
+
+    /**
+     * Underlying array to store the keys.
+     *
+     * <p>
+     * Terminology: <code>keys[ordinal] = key</code>
+     */
+    private LongArray keys;
+
+    /**
+     * Bitmasks to manipulate the hash table values.
+     */
+    private static final long MASK_ORDINAL = 0x00000000FFFFFFFFL;  // extract ordinal
+    private static final long MASK_FINGERPRINT = 0x0000FFFF00000000L;  // extract fingerprint
+    private static final long MASK_PSL = 0x7FFF000000000000L;  // extract PSL
+    private static final long INCR_PSL = 0x0001000000000000L;  // increment PSL by one
+
+    public ReorganizingLongHash(final BigArrays bigArrays) {
+        this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, bigArrays);
+    }
+
+    public ReorganizingLongHash(final long initialCapacity, final float loadFactor, final BigArrays bigArrays) {
+        assert initialCapacity > 0 : "initial capacity must be greater than 0";
+        assert loadFactor > 0 && loadFactor < 1 : "load factor must be between 0 and 1";
+
+        this.bigArrays = bigArrays;
+        this.loadFactor = loadFactor;
+
+        capacity = Numbers.nextPowerOfTwo((long) (initialCapacity / loadFactor));
+        assert capacity <= MAX_CAPACITY : "required capacity too large";
+        mask = capacity - 1;
+        grow = (long) (capacity * loadFactor);
+        size = 0;
+
+        table = bigArrays.newLongArray(capacity, false);
+        table.fill(0, capacity, -1);  // -1 represents an empty slot
+        keys = bigArrays.newLongArray(initialCapacity, false);
+    }
+
+    /**
+     * Adds the given key to the hash table and returns its ordinal.
+     * If the key exists already, it returns (-1 - ordinal).
+     */
+    public long add(final long key) {
+        final long ordinal = find(key);
+        if (ordinal != -1) {
+            return -1 - ordinal;
+        }
+
+        if (size >= grow) {
+            grow();
+        }
+
+        return insert(key);
+    }
+
+    /**
+     * Returns the key associated with the given ordinal.
+     * The result is undefined for an unused ordinal.
+     */
+    public long get(final long ordinal) {
+        return keys.get(ordinal);
+    }
+
+    /**
+     * Returns the ordinal associated with the given key, or -1 if the key doesn't exist.
+     *
+     * <p>
+     * Using the 64-bit hash value, up to 32 least significant bits (LSB) are used to identify the
+     * home slot in the hash table, and an additional 16 bits are used to identify the fingerprint.
+     * The fingerprint further increases the entropy and reduces the number of false lookups in the
+     * keys' table during equality checks, which is expensive due to an uncorrelated memory lookup.
+     *
+     * <p>
+     * Total entropy bits = 16 + log2(capacity)
+     *
+     * <p>
+     * Linear probing starts from the home slot, until a match or an empty slot is found.
+     * Values are first checked using their fingerprint (to reduce false positives), then verified
+     * in the keys' table using an equality check.
+     */
+    public long find(final long key) {
+        final long hash = hash(key);
+        final long fingerprint = hash & MASK_FINGERPRINT;
+
+        for (long idx = hash & mask, value, ordinal;; idx = (idx + 1) & mask) {
+            if ((value = table.get(idx)) == -1) {
+                return -1;
+            } else if (((value & MASK_FINGERPRINT) == fingerprint) && (keys.get((ordinal = (value & MASK_ORDINAL))) == key)) {
+                return ordinal;
+            }
+        }
+    }
+
+    /**
+     * Returns the number of mappings in this hash table.
+     */
+    public long size() {
+        return size;
+    }
+
+    /**
+     * Inserts the given key in the hash table and returns its ordinal.
+     *
+     * <p>
+     * Inspired by Robin Hood Hashing (RHH): if the PSL for the existing value is less than the PSL
+     * for the value being inserted, swap the two values and keep going. Values that were inserted
+     * early and thus "lucked out" on their PSLs will gradually be moved away from their preferred
+     * slot as new values come in that could make better use of that place in the table. It evens out
+     * the PSLs across the board and reduces the longest PSL dramatically.
+     *
+     * <p>
+     * A lower variance is better because, with modern CPU architectures, a PSL of 1 isn't much
+     * faster than a PSL of 3, because the main cost is fetching the cache line. The ideal hash
+     * table layout is the one where all values have equal PSLs, and that PSL fits within one cache line.
+     *
+     * <p>
+     * The expected longest PSL for a full table: <code>log(N)</code>
+     *
+     * <p>
+     * Our implementation has a slight variation on top of it: by loosening the guarantees provided
+     * by RHH, we can improve the performance on correlated lookups (such as aggregating on repeated
+     * timestamps) by moving the "recent" keys closer to their home slot, and eventually converging
+     * to the ideal hash table layout defined by RHH.
+     */
+    private long insert(final long key) {
+        final long hash = hash(key);
+        final long fingerprint = hash & MASK_FINGERPRINT;
+
+        // The ideal home slot for the given key.
+        long idx = hash & mask;
+
+        // The value yet to find an empty slot (candidate).
+        long value = fingerprint | size;
+
+        // The existing value at idx.
+        long existingValue;
+
+        // Always set the newly inserted key at its ideal home slot, even if it doesn't conform
+        // to the RHH scheme (yet). This will ensure subsequent correlated lookups are fast due
+        // to no additional probing. When another insertion causes this value to be displaced, it
+        // will eventually be placed at an appropriate location defined by the RHH scheme.
+        if ((value = table.set(idx, value)) == -1) {
+            // The ideal home slot was already empty; append the key and return early.
+            return append(key);
+        }
+
+        // Find an alternative slot for the displaced value such that the longest PSL is minimized.
+        do {
+            idx = (idx + 1) & mask;
+            value += INCR_PSL;
+
+            if ((existingValue = table.get(idx)) == -1) {
+                // Empty slot; insert the candidate value here.
+                table.set(idx, value);
+                return append(key);
+            } else if ((existingValue & MASK_PSL) <= (value & MASK_PSL)) {
+                // Existing value is "richer" than the candidate value at this index;
+                // swap and find an alternative slot for the displaced value.
+                // In the case of a tie, the candidate value (i.e. the recent value) is chosen as
+                // the winner and kept closer to its ideal home slot in order to speed up
+                // correlated lookups.
+                value = table.set(idx, value);
+            }
+        } while (true);
+    }
+
+    /**
+     * Appends the key in the keys' table.
+     */
+    private long append(final long key) {
+        keys = bigArrays.grow(keys, size + 1);
+        keys.set(size, key);
+        return size++;
+    }
+
+    /**
+     * Returns the hash for the given key.
+     * Visible for unit-tests.
+     */
+    long hash(final long key) {
+        return BitMixer.mix64(key);
+    }
+
+    /**
+     * Returns the underlying hash table.
+     * Visible for unit-tests.
+     */
+    LongArray getTable() {
+        return table;
+    }
+
+    /**
+     * Grows the hash table by doubling its capacity and reinserting the keys.
+     */
+    private void grow() {
+        // Ensure that the hash table doesn't grow too large.
+        // This implicitly also ensures that the ordinals are no larger than 2^32, thus,
+        // preventing them from polluting other bits (PSL/fingerprint) in the hash table values.
+        assert capacity < MAX_CAPACITY : "hash table already at the max capacity";
+
+        final long oldSize = size;
+        capacity <<= 1;
+        mask = capacity - 1;
+        size = 0;
+        grow = (long) (capacity * loadFactor);
+        table = bigArrays.resize(table, capacity);
+        table.fill(0, capacity, -1);
+
+        for (long ordinal = 0; ordinal < oldSize; ordinal++) {
+            insert(keys.get(ordinal));
+        }
+    }
+
+    @Override
+    public void close() {
+        Releasables.close(table, keys);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/util/SetBackedScalingCuckooFilter.java b/server/src/main/java/org/opensearch/common/util/SetBackedScalingCuckooFilter.java
index 474e33ccf29f1..e99eb751babe8 100644
--- a/server/src/main/java/org/opensearch/common/util/SetBackedScalingCuckooFilter.java
+++ b/server/src/main/java/org/opensearch/common/util/SetBackedScalingCuckooFilter.java
@@ -34,9 +34,9 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.hash.MurmurHash3;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -61,6 +61,8 @@
  * <p>
  * This datastructure scales as more values are inserted by growing the list of CuckooFilters.
  * Final size is dependent on the cardinality of data inserted, and the precision specified.
+ *
+ * @opensearch.internal
  */
 public class SetBackedScalingCuckooFilter implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/SingleObjectCache.java b/server/src/main/java/org/opensearch/common/util/SingleObjectCache.java
index dafcff9dfd11d..c2c5613f0f301 100644
--- a/server/src/main/java/org/opensearch/common/util/SingleObjectCache.java
+++ b/server/src/main/java/org/opensearch/common/util/SingleObjectCache.java
@@ -39,6 +39,8 @@
 /**
  * A very simple single object cache that allows non-blocking refresh calls
  * triggered by expiry time.
+ *
+ * @opensearch.internal
  */
 public abstract class SingleObjectCache<T> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/Streak.java b/server/src/main/java/org/opensearch/common/util/Streak.java
new file mode 100644
index 0000000000000..5f6ad3021659e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/Streak.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Streak is a data structure that keeps track of the number of successive successful events.
+ *
+ * @opensearch.internal
+ */
+public class Streak {
+    private final AtomicInteger successiveSuccessfulEvents = new AtomicInteger();
+
+    public int record(boolean isSuccessful) {
+        if (isSuccessful) {
+            return successiveSuccessfulEvents.incrementAndGet();
+        } else {
+            successiveSuccessfulEvents.set(0);
+            return 0;
+        }
+    }
+
+    public int length() {
+        return successiveSuccessfulEvents.get();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/util/TokenBucket.java b/server/src/main/java/org/opensearch/common/util/TokenBucket.java
new file mode 100644
index 0000000000000..d2e7e836bf07f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/TokenBucket.java
@@ -0,0 +1,124 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.LongSupplier;
+
+/**
+ * TokenBucket is used to limit the number of operations at a constant rate while allowing for short bursts.
+ *
+ * @opensearch.internal
+ */
+public class TokenBucket {
+    /**
+     * Defines a monotonically increasing counter.
+     *
+     * Usage examples:
+     * 1. clock = System::nanoTime can be used to perform rate-limiting per unit time
+     * 2. clock = AtomicLong::get can be used to perform rate-limiting per unit number of operations
+     */
+    private final LongSupplier clock;
+
+    /**
+     * Defines the number of tokens added to the bucket per clock cycle.
+     */
+    private final double rate;
+
+    /**
+     * Defines the capacity and the maximum number of operations that can be performed per clock cycle before
+     * the bucket runs out of tokens.
+     */
+    private final double burst;
+
+    /**
+     * Defines the current state of the token bucket.
+     */
+    private final AtomicReference<State> state;
+
+    public TokenBucket(LongSupplier clock, double rate, double burst) {
+        this(clock, rate, burst, burst);
+    }
+
+    public TokenBucket(LongSupplier clock, double rate, double burst, double initialTokens) {
+        if (rate <= 0.0) {
+            throw new IllegalArgumentException("rate must be greater than zero");
+        }
+
+        if (burst <= 0.0) {
+            throw new IllegalArgumentException("burst must be greater than zero");
+        }
+
+        this.clock = clock;
+        this.rate = rate;
+        this.burst = burst;
+        this.state = new AtomicReference<>(new State(Math.min(initialTokens, burst), clock.getAsLong()));
+    }
+
+    /**
+     * If there are enough tokens in the bucket, it requests/deducts 'n' tokens and returns true.
+     * Otherwise, returns false and leaves the bucket untouched.
+     */
+    public boolean request(double n) {
+        if (n <= 0) {
+            throw new IllegalArgumentException("requested tokens must be greater than zero");
+        }
+
+        // Refill tokens
+        State currentState, updatedState;
+        do {
+            currentState = state.get();
+            long now = clock.getAsLong();
+            double incr = (now - currentState.lastRefilledAt) * rate;
+            updatedState = new State(Math.min(currentState.tokens + incr, burst), now);
+        } while (state.compareAndSet(currentState, updatedState) == false);
+
+        // Deduct tokens
+        do {
+            currentState = state.get();
+            if (currentState.tokens < n) {
+                return false;
+            }
+            updatedState = new State(currentState.tokens - n, currentState.lastRefilledAt);
+        } while (state.compareAndSet(currentState, updatedState) == false);
+
+        return true;
+    }
+
+    public boolean request() {
+        return request(1.0);
+    }
+
+    /**
+     * Represents an immutable token bucket state.
+     */
+    private static class State {
+        final double tokens;
+        final long lastRefilledAt;
+
+        public State(double tokens, long lastRefilledAt) {
+            this.tokens = tokens;
+            this.lastRefilledAt = lastRefilledAt;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            State state = (State) o;
+            return Double.compare(state.tokens, tokens) == 0 && lastRefilledAt == state.lastRefilledAt;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(tokens, lastRefilledAt);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/util/URIPattern.java b/server/src/main/java/org/opensearch/common/util/URIPattern.java
index 2558374dda24b..a3c385e5ea660 100644
--- a/server/src/main/java/org/opensearch/common/util/URIPattern.java
+++ b/server/src/main/java/org/opensearch/common/util/URIPattern.java
@@ -44,6 +44,8 @@
  *
  * For example: foobar://*.local/some_path/*?*#* will match all uris with schema foobar in local domain
  * with any port, with path that starts some_path and with any query and fragment.
+ *
+ * @opensearch.internal
  */
 public class URIPattern {
     private final URI uriPattern;
diff --git a/server/src/main/java/org/opensearch/common/util/UploadListener.java b/server/src/main/java/org/opensearch/common/util/UploadListener.java
new file mode 100644
index 0000000000000..66feb68f7bf0d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/UploadListener.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+/**
+ * A tracker class that is fed to FileUploader.
+ *
+ * @opensearch.internal
+ */
+public interface UploadListener {
+
+    void beforeUpload(String file);
+
+    void onSuccess(String file);
+
+    void onFailure(String file);
+}
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractAsyncTask.java b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractAsyncTask.java
index 337fd59cfce7c..7c599476e263d 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractAsyncTask.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractAsyncTask.java
@@ -43,6 +43,8 @@
 
 /**
  * A base class for tasks that need to repeat.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractAsyncTask implements Runnable, Closeable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnable.java b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnable.java
index c283c5c618390..12fe437b390bf 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnable.java
@@ -32,7 +32,7 @@
 package org.opensearch.common.util.concurrent;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.component.Lifecycle;
+import org.opensearch.common.lifecycle.Lifecycle;
 
 import java.util.Objects;
 
@@ -40,6 +40,8 @@
  * {@code AbstractLifecycleRunnable} is a service-lifecycle aware {@link AbstractRunnable}.
  * <p>
  * This simplifies the running and rescheduling of {@link Lifecycle}-based {@code Runnable}s.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractLifecycleRunnable extends AbstractRunnable {
     /**
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractRunnable.java b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractRunnable.java
index 446e563575e7d..3afeb10bcb9fa 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/AbstractRunnable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/AbstractRunnable.java
@@ -34,6 +34,8 @@
 
 /**
  * An extension to runnable.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractRunnable implements Runnable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/AsyncIOProcessor.java b/server/src/main/java/org/opensearch/common/util/concurrent/AsyncIOProcessor.java
index d04982da32704..e9b9442c555e5 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/AsyncIOProcessor.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/AsyncIOProcessor.java
@@ -49,12 +49,15 @@
  * by a single worker. A worker in this context can be any caller of the {@link #put(Object, Consumer)} method since it will
  * hijack a worker if nobody else is currently processing queued items. If the internal queue has reached it's capacity incoming threads
  * might be blocked until other items are processed
+ *
+ * @opensearch.internal
  */
 public abstract class AsyncIOProcessor<Item> {
     private final Logger logger;
     private final ArrayBlockingQueue<Tuple<Item, Consumer<Exception>>> queue;
     private final ThreadContext threadContext;
     private final Semaphore promiseSemaphore = new Semaphore(1);
+    private long lastRunStartTimeInNs;
 
     protected AsyncIOProcessor(Logger logger, int queueSize, ThreadContext threadContext) {
         this.logger = logger;
@@ -65,7 +68,7 @@ protected AsyncIOProcessor(Logger logger, int queueSize, ThreadContext threadCon
     /**
      * Adds the given item to the queue. The listener is notified once the item is processed
      */
-    public final void put(Item item, Consumer<Exception> listener) {
+    public void put(Item item, Consumer<Exception> listener) {
         Objects.requireNonNull(item, "item must not be null");
         Objects.requireNonNull(listener, "listener must not be null");
         // the algorithm here tires to reduce the load on each individual caller.
@@ -76,12 +79,7 @@ public final void put(Item item, Consumer<Exception> listener) {
         final boolean promised = promiseSemaphore.tryAcquire();
         if (promised == false) {
             // in this case we are not responsible and can just block until there is space
-            try {
-                queue.put(new Tuple<>(item, preserveContext(listener)));
-            } catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
-                listener.accept(e);
-            }
+            addToQueue(item, listener);
         }
 
         // here we have to try to make the promise again otherwise there is a race when a thread puts an entry without making the promise
@@ -102,7 +100,17 @@ public final void put(Item item, Consumer<Exception> listener) {
         }
     }
 
-    private void drainAndProcessAndRelease(List<Tuple<Item, Consumer<Exception>>> candidates) {
+    void addToQueue(Item item, Consumer<Exception> listener) {
+        try {
+            queue.put(new Tuple<>(item, preserveContext(listener)));
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            listener.accept(e);
+        }
+    }
+
+    void drainAndProcessAndRelease(List<Tuple<Item, Consumer<Exception>>> candidates) {
+        lastRunStartTimeInNs = System.nanoTime();
         Exception exception;
         try {
             queue.drainTo(candidates);
@@ -128,7 +136,7 @@ private Exception processList(List<Tuple<Item, Consumer<Exception>>> candidates)
         return exception;
     }
 
-    private void notifyList(List<Tuple<Item, Consumer<Exception>>> candidates, Exception exception) {
+    void notifyList(List<Tuple<Item, Consumer<Exception>>> candidates, Exception exception) {
         for (Tuple<Item, Consumer<Exception>> tuple : candidates) {
             Consumer<Exception> consumer = tuple.v2();
             try {
@@ -139,7 +147,7 @@ private void notifyList(List<Tuple<Item, Consumer<Exception>>> candidates, Excep
         }
     }
 
-    private Consumer<Exception> preserveContext(Consumer<Exception> consumer) {
+    Consumer<Exception> preserveContext(Consumer<Exception> consumer) {
         Supplier<ThreadContext.StoredContext> restorableContext = threadContext.newRestorableContext(false);
         return e -> {
             try (ThreadContext.StoredContext ignore = restorableContext.get()) {
@@ -152,4 +160,20 @@ private Consumer<Exception> preserveContext(Consumer<Exception> consumer) {
      * Writes or processes the items out or to disk.
      */
     protected abstract void write(List<Tuple<Item, Consumer<Exception>>> candidates) throws IOException;
+
+    Logger getLogger() {
+        return logger;
+    }
+
+    Semaphore getPromiseSemaphore() {
+        return promiseSemaphore;
+    }
+
+    long getLastRunStartTimeInNs() {
+        return lastRunStartTimeInNs;
+    }
+
+    ArrayBlockingQueue<Tuple<Item, Consumer<Exception>>> getQueue() {
+        return queue;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/AtomicArray.java b/server/src/main/java/org/opensearch/common/util/concurrent/AtomicArray.java
index efb8fce467a21..dd1f71a7d2166 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/AtomicArray.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/AtomicArray.java
@@ -42,6 +42,8 @@
 /**
  * A list backed by an {@link AtomicReferenceArray} with potential null values, easily allowing
  * to get the concrete values as a list using {@link #asList()}.
+ *
+ * @opensearch.internal
  */
 public class AtomicArray<E> {
     private final AtomicReferenceArray<E> array;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/BaseFuture.java b/server/src/main/java/org/opensearch/common/util/concurrent/BaseFuture.java
index 14c6c366f0bb9..47fc4fc33bd74 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/BaseFuture.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/BaseFuture.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.util.concurrent;
 
 import org.opensearch.cluster.service.ClusterApplierService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.common.Nullable;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transports;
@@ -46,6 +46,11 @@
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.locks.AbstractQueuedSynchronizer;
 
+/**
+ * Base future class.
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseFuture<V> implements Future<V> {
 
     private static final String BLOCKING_OP_REASON = "Blocking operation";
@@ -104,7 +109,7 @@ protected boolean blockingAllowed() {
         return Transports.assertNotTransportThread(BLOCKING_OP_REASON)
             && ThreadPool.assertNotScheduleThread(BLOCKING_OP_REASON)
             && ClusterApplierService.assertNotClusterStateUpdateThread(BLOCKING_OP_REASON)
-            && MasterService.assertNotMasterUpdateThread(BLOCKING_OP_REASON);
+            && ClusterManagerService.assertNotClusterManagerUpdateThread(BLOCKING_OP_REASON);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessor.java b/server/src/main/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessor.java
new file mode 100644
index 0000000000000..be2029b2e7c62
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessor.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util.concurrent;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+
+/**
+ * A variant of {@link AsyncIOProcessor} that allows to batch and buffer processing items at every
+ * {@link BufferedAsyncIOProcessor#getBufferInterval()} in a separate threadpool.
+ * <p>
+ * Requests are buffered till processor thread calls @{link drainAndProcessAndRelease} after bufferInterval.
+ * If more requests are enqueued between invocations of drainAndProcessAndRelease, another processor thread
+ * gets scheduled. Subsequent requests will get buffered till drainAndProcessAndRelease gets called in this new
+ * processor thread.
+ *
+ * @opensearch.internal
+ */
+public abstract class BufferedAsyncIOProcessor<Item> extends AsyncIOProcessor<Item> {
+
+    private final ThreadPool threadpool;
+    private final Supplier<TimeValue> bufferIntervalSupplier;
+
+    protected BufferedAsyncIOProcessor(
+        Logger logger,
+        int queueSize,
+        ThreadContext threadContext,
+        ThreadPool threadpool,
+        Supplier<TimeValue> bufferIntervalSupplier
+    ) {
+        super(logger, queueSize, threadContext);
+        this.threadpool = threadpool;
+        this.bufferIntervalSupplier = bufferIntervalSupplier;
+    }
+
+    @Override
+    public void put(Item item, Consumer<Exception> listener) {
+        Objects.requireNonNull(item, "item must not be null");
+        Objects.requireNonNull(listener, "listener must not be null");
+        addToQueue(item, listener);
+        scheduleProcess();
+    }
+
+    private void scheduleProcess() {
+        if (getQueue().isEmpty() == false && getPromiseSemaphore().tryAcquire()) {
+            try {
+                threadpool.schedule(this::process, getBufferInterval(), getBufferProcessThreadPoolName());
+            } catch (Exception e) {
+                getLogger().error("failed to schedule process");
+                processSchedulingFailure(e);
+                getPromiseSemaphore().release();
+                // This is to make sure that any new items that are added to the queue between processSchedulingFailure
+                // and releasing the semaphore is handled by a subsequent refresh and not starved.
+                scheduleProcess();
+            }
+        }
+    }
+
+    private void processSchedulingFailure(Exception e) {
+        List<Tuple<Item, Consumer<Exception>>> candidates = new ArrayList<>();
+        getQueue().drainTo(candidates);
+        notifyList(candidates, e);
+    }
+
+    private void process() {
+        drainAndProcessAndRelease(new ArrayList<>());
+        scheduleProcess();
+    }
+
+    private TimeValue getBufferInterval() {
+        long bufferInterval = bufferIntervalSupplier.get().getNanos();
+        long timeSinceLastRunStartInNS = System.nanoTime() - getLastRunStartTimeInNs();
+        if (timeSinceLastRunStartInNS >= bufferInterval) {
+            return TimeValue.ZERO;
+        }
+        return TimeValue.timeValueNanos(bufferInterval - timeSinceLastRunStartInNS);
+    }
+
+    protected abstract String getBufferProcessThreadPoolName();
+
+    // Exclusively for testing, please do not use it elsewhere.
+    public Supplier<TimeValue> getBufferIntervalSupplier() {
+        return bufferIntervalSupplier;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/CountDown.java b/server/src/main/java/org/opensearch/common/util/concurrent/CountDown.java
index 23843b9e0c5bf..9dc67ab40dba2 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/CountDown.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/CountDown.java
@@ -39,6 +39,8 @@
  * A simple thread safe count-down class that in contrast to a {@link CountDownLatch}
  * never blocks. This class is useful if a certain action has to wait for N concurrent
  * tasks to return or a timeout to occur in order to proceed.
+ *
+ * @opensearch.internal
  */
 public final class CountDown {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/FutureUtils.java b/server/src/main/java/org/opensearch/common/util/concurrent/FutureUtils.java
index 50ab3bccf6b90..83fdbf8790eba 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/FutureUtils.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/FutureUtils.java
@@ -41,6 +41,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
+/**
+ * Future utilities.
+ *
+ * @opensearch.internal
+ */
 public class FutureUtils {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/KeyedLock.java b/server/src/main/java/org/opensearch/common/util/concurrent/KeyedLock.java
index 5b2cb6c2312fe..9d4235f8d8a1a 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/KeyedLock.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/KeyedLock.java
@@ -46,7 +46,8 @@
  * infinitely.
  * Note: this lock is reentrant
  *
- * */
+ * @opensearch.internal
+ */
 public final class KeyedLock<T> {
 
     private final ConcurrentMap<T, KeyLock> map = ConcurrentCollections.newConcurrentMapWithAggressiveConcurrency();
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ListenableFuture.java b/server/src/main/java/org/opensearch/common/util/concurrent/ListenableFuture.java
index ce6fa0e46d0c0..b1f4714a90e8e 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ListenableFuture.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/ListenableFuture.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.common.util.concurrent;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.ContextPreservingActionListener;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -50,6 +50,8 @@
  * for execution in the provided {@link ExecutorService}. If the computation has already
  * been performed, a request to add a listener will simply result in execution of the listener
  * on the calling thread.
+ *
+ * @opensearch.internal
  */
 public final class ListenableFuture<V> extends BaseFuture<V> implements ActionListener<V> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchAbortPolicy.java b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchAbortPolicy.java
index aa13d1d8f5cb5..2ea38e45d54d5 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchAbortPolicy.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchAbortPolicy.java
@@ -33,10 +33,16 @@
 package org.opensearch.common.util.concurrent;
 
 import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 
+/**
+ * OpenSearch abortion policies.
+ *
+ * @opensearch.internal
+ */
 public class OpenSearchAbortPolicy implements XRejectedExecutionHandler {
     private final CounterMetric rejected = new CounterMetric();
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchExecutors.java b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchExecutors.java
index 5a967528a6ae2..e83f541101b69 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchExecutors.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchExecutors.java
@@ -40,6 +40,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.node.Node;
+import org.opensearch.threadpool.RunnableTaskExecutionListener;
+import org.opensearch.threadpool.TaskAwareRunnable;
 
 import java.util.List;
 import java.util.Optional;
@@ -55,8 +57,14 @@
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 
+/**
+ * Executors.
+ *
+ * @opensearch.internal
+ */
 public class OpenSearchExecutors {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(OpenSearchExecutors.class);
@@ -172,6 +180,31 @@ public static OpenSearchThreadPoolExecutor newFixed(
         );
     }
 
+    public static OpenSearchThreadPoolExecutor newAutoQueueFixed(
+        String name,
+        int size,
+        int initialQueueCapacity,
+        int minQueueSize,
+        int maxQueueSize,
+        int frameSize,
+        TimeValue targetedResponseTime,
+        ThreadFactory threadFactory,
+        ThreadContext contextHolder
+    ) {
+        return newAutoQueueFixed(
+            name,
+            size,
+            initialQueueCapacity,
+            minQueueSize,
+            maxQueueSize,
+            frameSize,
+            targetedResponseTime,
+            threadFactory,
+            contextHolder,
+            null
+        );
+    }
+
     /**
      * Return a new executor that will automatically adjust the queue size based on queue throughput.
      *
@@ -180,6 +213,7 @@ public static OpenSearchThreadPoolExecutor newFixed(
      * @param minQueueSize minimum queue size that the queue can be adjusted to
      * @param maxQueueSize maximum queue size that the queue can be adjusted to
      * @param frameSize number of tasks during which stats are collected before adjusting queue size
+     * @param runnableTaskListener callback listener for a TaskAwareRunnable
      */
     public static OpenSearchThreadPoolExecutor newAutoQueueFixed(
         String name,
@@ -190,17 +224,30 @@ public static OpenSearchThreadPoolExecutor newAutoQueueFixed(
         int frameSize,
         TimeValue targetedResponseTime,
         ThreadFactory threadFactory,
-        ThreadContext contextHolder
+        ThreadContext contextHolder,
+        AtomicReference<RunnableTaskExecutionListener> runnableTaskListener
     ) {
         if (initialQueueCapacity <= 0) {
             throw new IllegalArgumentException(
                 "initial queue capacity for [" + name + "] executor must be positive, got: " + initialQueueCapacity
             );
         }
+
         ResizableBlockingQueue<Runnable> queue = new ResizableBlockingQueue<>(
             ConcurrentCollections.<Runnable>newBlockingQueue(),
             initialQueueCapacity
         );
+
+        Function<Runnable, WrappedRunnable> runnableWrapper;
+        if (runnableTaskListener != null) {
+            runnableWrapper = (runnable) -> {
+                TaskAwareRunnable taskAwareRunnable = new TaskAwareRunnable(contextHolder, runnable, runnableTaskListener);
+                return new TimedRunnable(taskAwareRunnable);
+            };
+        } else {
+            runnableWrapper = TimedRunnable::new;
+        }
+
         return new QueueResizingOpenSearchThreadPoolExecutor(
             name,
             size,
@@ -210,7 +257,7 @@ public static OpenSearchThreadPoolExecutor newAutoQueueFixed(
             queue,
             minQueueSize,
             maxQueueSize,
-            TimedRunnable::new,
+            runnableWrapper,
             frameSize,
             targetedResponseTime,
             threadFactory,
@@ -337,6 +384,11 @@ public static ThreadFactory daemonThreadFactory(String namePrefix) {
         return new OpenSearchThreadFactory(namePrefix);
     }
 
+    /**
+     * A thread factory
+     *
+     * @opensearch.internal
+     */
     static class OpenSearchThreadFactory implements ThreadFactory {
 
         final ThreadGroup group;
@@ -363,6 +415,11 @@ public Thread newThread(Runnable r) {
      */
     private OpenSearchExecutors() {}
 
+    /**
+     * A scaling queue for executors
+     *
+     * @opensearch.internal
+     */
     static class ExecutorScalingQueue<E> extends LinkedTransferQueue<E> {
 
         ThreadPoolExecutor executor;
@@ -396,6 +453,8 @@ public boolean offer(E e) {
     /**
      * A handler for rejected tasks that adds the specified element to this queue,
      * waiting if necessary for space to become available.
+     *
+     * @opensearch.internal
      */
     static class ForceQueuePolicy implements XRejectedExecutionHandler {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchThreadPoolExecutor.java b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchThreadPoolExecutor.java
index a04554f9b029c..afffec4790873 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchThreadPoolExecutor.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchThreadPoolExecutor.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.util.concurrent;
 
 import org.opensearch.common.SuppressForbidden;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ThreadFactory;
@@ -42,6 +43,8 @@
 
 /**
  * An extension to thread pool executor, allowing (in the future) to add specific additional stats to it.
+ *
+ * @opensearch.internal
  */
 public class OpenSearchThreadPoolExecutor extends ThreadPoolExecutor {
 
@@ -112,6 +115,11 @@ protected synchronized void terminated() {
         }
     }
 
+    /**
+     * Listener on shut down
+     *
+     * @opensearch.internal
+     */
     public interface ShutdownListener {
         void onTerminated();
     }
@@ -197,4 +205,15 @@ protected Runnable wrapRunnable(Runnable command) {
     protected Runnable unwrap(Runnable runnable) {
         return contextHolder.unwrap(runnable);
     }
+
+    /**
+     * Returns the cumulative wait time of the ThreadPool. If the ThreadPool does not support tracking the cumulative pool wait time
+     * then this should return -1 which will prevent the value from showing up in {@link org.opensearch.threadpool.ThreadPoolStats}.
+     * ThreadPools that do support this metric should override this method. For example, {@link QueueResizingOpenSearchThreadPoolExecutor}
+     * does so using the {@link TimedRunnable} to get the difference between Runnable creation and execution.
+     *
+     */
+    public long getPoolWaitTimeNanos() {
+        return -1;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedCallable.java b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedCallable.java
index 93250eea8e75b..806a6e11606df 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedCallable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedCallable.java
@@ -35,6 +35,11 @@
 
 import java.util.concurrent.Callable;
 
+/**
+ * A prioritized callable.
+ *
+ * @opensearch.internal
+ */
 public abstract class PrioritizedCallable<T> implements Callable<T>, Comparable<PrioritizedCallable> {
 
     private final Priority priority;
@@ -56,6 +61,11 @@ public Priority priority() {
         return priority;
     }
 
+    /**
+     * Wrapped generic
+     *
+     * @opensearch.internal
+     */
     static class Wrapped<T> extends PrioritizedCallable<T> {
 
         private final Callable<T> callable;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedOpenSearchThreadPoolExecutor.java b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedOpenSearchThreadPoolExecutor.java
index 797d476017005..d3d0f6080e7f6 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedOpenSearchThreadPoolExecutor.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedOpenSearchThreadPoolExecutor.java
@@ -53,6 +53,8 @@
  * be wrapped and assign a default {@link Priority#NORMAL} priority.
  * <p>
  * Note, if two tasks have the same priority, the first to arrive will be executed first (FIFO style).
+ *
+ * @opensearch.internal
  */
 public class PrioritizedOpenSearchThreadPoolExecutor extends OpenSearchThreadPoolExecutor {
 
@@ -198,6 +200,11 @@ protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
         return new PrioritizedFutureTask<>((PrioritizedCallable) callable, insertionOrder.incrementAndGet());
     }
 
+    /**
+     * A pending thread
+     *
+     * @opensearch.internal
+     */
     public static class Pending {
         public final Object task;
         public final Priority priority;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedRunnable.java b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedRunnable.java
index 8a932b799eee6..96a74e44a576a 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedRunnable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/PrioritizedRunnable.java
@@ -36,6 +36,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.LongSupplier;
 
+/**
+ * A base prioritized runnable
+ *
+ * @opensearch.internal
+ */
 public abstract class PrioritizedRunnable implements Runnable, Comparable<PrioritizedRunnable> {
 
     private final Priority priority;
@@ -82,6 +87,11 @@ public Priority priority() {
         return priority;
     }
 
+    /**
+     * Wrapped runnable
+     *
+     * @opensearch.internal
+     */
     static class Wrapped extends PrioritizedRunnable implements WrappedRunnable {
 
         private final Runnable runnable;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/QueueResizingOpenSearchThreadPoolExecutor.java b/server/src/main/java/org/opensearch/common/util/concurrent/QueueResizingOpenSearchThreadPoolExecutor.java
index 39561039c5c6f..68bae3842b800 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/QueueResizingOpenSearchThreadPoolExecutor.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/QueueResizingOpenSearchThreadPoolExecutor.java
@@ -32,10 +32,11 @@
 
 package org.opensearch.common.util.concurrent;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.common.ExponentiallyWeightedMovingAverage;
+import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.unit.TimeValue;
 
 import java.util.Locale;
@@ -48,6 +49,8 @@
 /**
  * An extension to thread pool executor, which automatically adjusts the queue size of the
  * {@code ResizableBlockingQueue} according to Little's Law.
+ *
+ * @opensearch.internal
  */
 public final class QueueResizingOpenSearchThreadPoolExecutor extends OpenSearchThreadPoolExecutor {
 
@@ -65,6 +68,7 @@ public final class QueueResizingOpenSearchThreadPoolExecutor extends OpenSearchT
     private final int maxQueueSize;
     private final long targetedResponseTimeNanos;
     private final ExponentiallyWeightedMovingAverage executionEWMA;
+    private final CounterMetric poolWaitTime;
 
     private final AtomicLong totalTaskNanos = new AtomicLong(0);
     private final AtomicInteger taskCount = new AtomicInteger(0);
@@ -96,6 +100,7 @@ public final class QueueResizingOpenSearchThreadPoolExecutor extends OpenSearchT
         this.maxQueueSize = maxQueueSize;
         this.targetedResponseTimeNanos = targetedResponseTime.getNanos();
         this.executionEWMA = new ExponentiallyWeightedMovingAverage(EWMA_ALPHA, 0);
+        this.poolWaitTime = new CounterMetric();
         logger.debug(
             "thread pool [{}] will adjust queue by [{}] when determining automatic queue size",
             getName(),
@@ -187,6 +192,7 @@ protected void afterExecute(Runnable r, Throwable t) {
             // taskExecutionNanos may be -1 if the task threw an exception
             executionEWMA.addValue(taskExecutionNanos);
         }
+        poolWaitTime.inc(timedRunnable.getWaitTimeNanos());
 
         if (taskCount.incrementAndGet() == this.tasksPerFrame) {
             final long endTimeNs = System.nanoTime();
@@ -287,4 +293,8 @@ protected void appendThreadPoolExecutorDetails(StringBuilder sb) {
         sb.append("adjustment amount = ").append(QUEUE_ADJUSTMENT_AMOUNT).append(", ");
     }
 
+    @Override
+    public long getPoolWaitTimeNanos() {
+        return poolWaitTime.count();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ReleasableLock.java b/server/src/main/java/org/opensearch/common/util/concurrent/ReleasableLock.java
index afa793b009f15..7c0368793ca27 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ReleasableLock.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/ReleasableLock.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.common.util.concurrent;
 
-import org.opensearch.Assertions;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.Assertions;
 import org.opensearch.index.engine.EngineException;
 
 import java.util.concurrent.locks.Lock;
 
 /**
  * Releasable lock used inside of Engine implementations
+ *
+ * @opensearch.internal
  */
 public class ReleasableLock implements Releasable {
     private final Lock lock;
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ResizableBlockingQueue.java b/server/src/main/java/org/opensearch/common/util/concurrent/ResizableBlockingQueue.java
index bf8a9c86870fa..7ef40ba2f086e 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ResizableBlockingQueue.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/ResizableBlockingQueue.java
@@ -37,6 +37,8 @@
 /**
  * Extends the {@code SizeBlockingQueue} to add the {@code adjustCapacity} method, which will adjust
  * the capacity by a certain amount towards a maximum or minimum.
+ *
+ * @opensearch.internal
  */
 final class ResizableBlockingQueue<E> extends SizeBlockingQueue<E> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/RunOnce.java b/server/src/main/java/org/opensearch/common/util/concurrent/RunOnce.java
index a2bb53ad909fb..5539b5efa4a1c 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/RunOnce.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/RunOnce.java
@@ -36,6 +36,8 @@
 
 /**
  * Runnable that can only be run one time.
+ *
+ * @opensearch.internal
  */
 public class RunOnce implements Runnable {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/SizeBlockingQueue.java b/server/src/main/java/org/opensearch/common/util/concurrent/SizeBlockingQueue.java
index d2d50eb95edb1..ad790b8dbd418 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/SizeBlockingQueue.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/SizeBlockingQueue.java
@@ -43,6 +43,8 @@
  * A size based queue wrapping another blocking queue to provide (somewhat relaxed) capacity checks.
  * Mainly makes sense to use with blocking queues that are unbounded to provide the ability to do
  * capacity verification.
+ *
+ * @opensearch.internal
  */
 public class SizeBlockingQueue<E> extends AbstractQueue<E> implements BlockingQueue<E> {
 
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContext.java b/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContext.java
index d844a8f158ea4..4888d25e4a640 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContext.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContext.java
@@ -37,14 +37,15 @@
 import org.opensearch.client.OriginSettingClient;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.http.HttpTransportSettings;
 import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskThreadContextStatePropagator;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -56,7 +57,9 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.BiConsumer;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
@@ -94,6 +97,7 @@
  *     // previous context is restored on StoredContext#close()
  * </pre>
  *
+ * @opensearch.internal
  */
 public final class ThreadContext implements Writeable {
 
@@ -111,6 +115,7 @@ public final class ThreadContext implements Writeable {
     private final ThreadLocal<ThreadContextStruct> threadLocal;
     private final int maxWarningHeaderCount;
     private final long maxWarningHeaderSize;
+    private final List<ThreadContextStatePropagator> propagators;
 
     /**
      * Creates a new ThreadContext instance
@@ -121,6 +126,15 @@ public ThreadContext(Settings settings) {
         this.threadLocal = ThreadLocal.withInitial(() -> DEFAULT_CONTEXT);
         this.maxWarningHeaderCount = SETTING_HTTP_MAX_WARNING_HEADER_COUNT.get(settings);
         this.maxWarningHeaderSize = SETTING_HTTP_MAX_WARNING_HEADER_SIZE.get(settings).getBytes();
+        this.propagators = new CopyOnWriteArrayList<>(List.of(new TaskThreadContextStatePropagator()));
+    }
+
+    public void registerThreadContextStatePropagator(final ThreadContextStatePropagator propagator) {
+        propagators.add(Objects.requireNonNull(propagator));
+    }
+
+    public void unregisterThreadContextStatePropagator(final ThreadContextStatePropagator propagator) {
+        propagators.remove(Objects.requireNonNull(propagator));
     }
 
     /**
@@ -134,16 +148,24 @@ public StoredContext stashContext() {
          * This is needed so the DeprecationLogger in another thread can see the value of X-Opaque-ID provided by a user.
          * Otherwise when context is stash, it should be empty.
          */
+
+        ThreadContextStruct threadContextStruct = DEFAULT_CONTEXT.putPersistent(context.persistentHeaders);
+
         if (context.requestHeaders.containsKey(Task.X_OPAQUE_ID)) {
-            ThreadContextStruct threadContextStruct = DEFAULT_CONTEXT.putHeaders(
+            threadContextStruct = threadContextStruct.putHeaders(
                 MapBuilder.<String, String>newMapBuilder()
                     .put(Task.X_OPAQUE_ID, context.requestHeaders.get(Task.X_OPAQUE_ID))
                     .immutableMap()
             );
-            threadLocal.set(threadContextStruct);
-        } else {
-            threadLocal.set(DEFAULT_CONTEXT);
         }
+
+        final Map<String, Object> transientHeaders = propagateTransients(context.transientHeaders);
+        if (!transientHeaders.isEmpty()) {
+            threadContextStruct = threadContextStruct.putTransient(transientHeaders);
+        }
+
+        threadLocal.set(threadContextStruct);
+
         return () -> {
             // If the node and thus the threadLocal get closed while this task
             // is still executing, we don't want this runnable to fail with an
@@ -157,7 +179,10 @@ public StoredContext stashContext() {
      */
     public Writeable captureAsWriteable() {
         final ThreadContextStruct context = threadLocal.get();
-        return out -> context.writeTo(out, defaultHeader);
+        return out -> {
+            final Map<String, String> propagatedHeaders = propagateHeaders(context.transientHeaders);
+            context.writeTo(out, defaultHeader, propagatedHeaders);
+        };
     }
 
     /**
@@ -215,21 +240,29 @@ public StoredContext newStoredContext(boolean preserveResponseHeaders) {
      */
     public StoredContext newStoredContext(boolean preserveResponseHeaders, Collection<String> transientHeadersToClear) {
         final ThreadContextStruct originalContext = threadLocal.get();
+        final Map<String, Object> newTransientHeaders = new HashMap<>(originalContext.transientHeaders);
+
+        boolean transientHeadersModified = false;
+        final Map<String, Object> transientHeaders = propagateTransients(originalContext.transientHeaders);
+        if (!transientHeaders.isEmpty()) {
+            newTransientHeaders.putAll(transientHeaders);
+            transientHeadersModified = true;
+        }
+
         // clear specific transient headers from the current context
-        Map<String, Object> newTransientHeaders = null;
         for (String transientHeaderToClear : transientHeadersToClear) {
-            if (originalContext.transientHeaders.containsKey(transientHeaderToClear)) {
-                if (newTransientHeaders == null) {
-                    newTransientHeaders = new HashMap<>(originalContext.transientHeaders);
-                }
+            if (newTransientHeaders.containsKey(transientHeaderToClear)) {
                 newTransientHeaders.remove(transientHeaderToClear);
+                transientHeadersModified = true;
             }
         }
-        if (newTransientHeaders != null) {
+
+        if (transientHeadersModified == true) {
             ThreadContextStruct threadContextStruct = new ThreadContextStruct(
                 originalContext.requestHeaders,
                 originalContext.responseHeaders,
                 newTransientHeaders,
+                originalContext.persistentHeaders,
                 originalContext.isSystemContext,
                 originalContext.warningHeadersSize
             );
@@ -237,6 +270,7 @@ public StoredContext newStoredContext(boolean preserveResponseHeaders, Collectio
         }
         // this is the context when this method returns
         final ThreadContextStruct newContext = threadLocal.get();
+
         return () -> {
             if (preserveResponseHeaders && threadLocal.get() != newContext) {
                 threadLocal.set(originalContext.putResponseHeaders(threadLocal.get().responseHeaders));
@@ -285,7 +319,9 @@ public Supplier<StoredContext> wrapRestorable(StoredContext storedContext) {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        threadLocal.get().writeTo(out, defaultHeader);
+        final ThreadContextStruct context = threadLocal.get();
+        final Map<String, String> propagatedHeaders = propagateHeaders(context.transientHeaders);
+        context.writeTo(out, defaultHeader, propagatedHeaders);
     }
 
     /**
@@ -302,7 +338,7 @@ public void setHeaders(Tuple<Map<String, String>, Map<String, Set<String>>> head
         if (requestHeaders.isEmpty() && responseHeaders.isEmpty()) {
             struct = ThreadContextStruct.EMPTY;
         } else {
-            struct = new ThreadContextStruct(requestHeaders, responseHeaders, Collections.emptyMap(), false);
+            struct = new ThreadContextStruct(requestHeaders, responseHeaders, Collections.emptyMap(), Collections.emptyMap(), false);
         }
         threadLocal.set(struct);
     }
@@ -340,6 +376,13 @@ public String getHeader(String key) {
         return value;
     }
 
+    /**
+     * Returns the persistent header for the given key or <code>null</code> if not present - persistent headers cannot be stashed
+     */
+    public Object getPersistent(String key) {
+        return threadLocal.get().persistentHeaders.get(key);
+    }
+
     /**
      * Returns all of the request headers from the thread's context.<br>
      * <b>Be advised, headers might contain credentials.</b>
@@ -399,6 +442,20 @@ public void putHeader(Map<String, String> header) {
         threadLocal.set(threadLocal.get().putHeaders(header));
     }
 
+    /**
+     * Puts a persistent header into the context - persistent headers cannot be stashed
+     */
+    public void putPersistent(String key, Object value) {
+        threadLocal.set(threadLocal.get().putPersistent(key, value));
+    }
+
+    /**
+     * Puts all of the given headers into this persistent context - persistent headers cannot be stashed
+     */
+    public void putPersistent(Map<String, Object> persistentHeaders) {
+        threadLocal.set(threadLocal.get().putPersistent(persistentHeaders));
+    }
+
     /**
      * Puts a transient header object into this context
      */
@@ -485,6 +542,11 @@ public boolean isSystemContext() {
         return threadLocal.get().isSystemContext;
     }
 
+    /**
+     * A stored context
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface StoredContext extends AutoCloseable {
         @Override
@@ -508,18 +570,32 @@ public static Map<String, String> buildDefaultHeaders(Settings settings) {
         }
     }
 
+    private Map<String, Object> propagateTransients(Map<String, Object> source) {
+        final Map<String, Object> transients = new HashMap<>();
+        propagators.forEach(p -> transients.putAll(p.transients(source)));
+        return transients;
+    }
+
+    private Map<String, String> propagateHeaders(Map<String, Object> source) {
+        final Map<String, String> headers = new HashMap<>();
+        propagators.forEach(p -> headers.putAll(p.headers(source)));
+        return headers;
+    }
+
     private static final class ThreadContextStruct {
 
         private static final ThreadContextStruct EMPTY = new ThreadContextStruct(
             Collections.emptyMap(),
             Collections.emptyMap(),
             Collections.emptyMap(),
+            Collections.emptyMap(),
             false
         );
 
         private final Map<String, String> requestHeaders;
         private final Map<String, Object> transientHeaders;
         private final Map<String, Set<String>> responseHeaders;
+        private final Map<String, Object> persistentHeaders;
         private final boolean isSystemContext;
         // saving current warning headers' size not to recalculate the size with every new warning header
         private final long warningHeadersSize;
@@ -528,18 +604,20 @@ private ThreadContextStruct setSystemContext() {
             if (isSystemContext) {
                 return this;
             }
-            return new ThreadContextStruct(requestHeaders, responseHeaders, transientHeaders, true);
+            return new ThreadContextStruct(requestHeaders, responseHeaders, transientHeaders, persistentHeaders, true);
         }
 
         private ThreadContextStruct(
             Map<String, String> requestHeaders,
             Map<String, Set<String>> responseHeaders,
             Map<String, Object> transientHeaders,
+            Map<String, Object> persistentHeaders,
             boolean isSystemContext
         ) {
             this.requestHeaders = requestHeaders;
             this.responseHeaders = responseHeaders;
             this.transientHeaders = transientHeaders;
+            this.persistentHeaders = persistentHeaders;
             this.isSystemContext = isSystemContext;
             this.warningHeadersSize = 0L;
         }
@@ -548,12 +626,14 @@ private ThreadContextStruct(
             Map<String, String> requestHeaders,
             Map<String, Set<String>> responseHeaders,
             Map<String, Object> transientHeaders,
+            Map<String, Object> persistentHeaders,
             boolean isSystemContext,
             long warningHeadersSize
         ) {
             this.requestHeaders = requestHeaders;
             this.responseHeaders = responseHeaders;
             this.transientHeaders = transientHeaders;
+            this.persistentHeaders = persistentHeaders;
             this.isSystemContext = isSystemContext;
             this.warningHeadersSize = warningHeadersSize;
         }
@@ -562,13 +642,13 @@ private ThreadContextStruct(
          * This represents the default context and it should only ever be called by {@link #DEFAULT_CONTEXT}.
          */
         private ThreadContextStruct() {
-            this(Collections.emptyMap(), Collections.emptyMap(), Collections.emptyMap(), false);
+            this(Collections.emptyMap(), Collections.emptyMap(), Collections.emptyMap(), Collections.emptyMap(), false);
         }
 
         private ThreadContextStruct putRequest(String key, String value) {
             Map<String, String> newRequestHeaders = new HashMap<>(this.requestHeaders);
             putSingleHeader(key, value, newRequestHeaders);
-            return new ThreadContextStruct(newRequestHeaders, responseHeaders, transientHeaders, isSystemContext);
+            return new ThreadContextStruct(newRequestHeaders, responseHeaders, transientHeaders, persistentHeaders, isSystemContext);
         }
 
         private static <T> void putSingleHeader(String key, T value, Map<String, T> newHeaders) {
@@ -585,7 +665,25 @@ private ThreadContextStruct putHeaders(Map<String, String> headers) {
                 for (Map.Entry<String, String> entry : headers.entrySet()) {
                     putSingleHeader(entry.getKey(), entry.getValue(), newHeaders);
                 }
-                return new ThreadContextStruct(newHeaders, responseHeaders, transientHeaders, isSystemContext);
+                return new ThreadContextStruct(newHeaders, responseHeaders, transientHeaders, persistentHeaders, isSystemContext);
+            }
+        }
+
+        private ThreadContextStruct putPersistent(String key, Object value) {
+            Map<String, Object> newPersistentHeaders = new HashMap<>(this.persistentHeaders);
+            putSingleHeader(key, value, newPersistentHeaders);
+            return new ThreadContextStruct(requestHeaders, responseHeaders, transientHeaders, newPersistentHeaders, isSystemContext);
+        }
+
+        private ThreadContextStruct putPersistent(Map<String, Object> headers) {
+            if (headers.isEmpty()) {
+                return this;
+            } else {
+                final Map<String, Object> newPersistentHeaders = new HashMap<>(this.persistentHeaders);
+                for (Map.Entry<String, Object> entry : headers.entrySet()) {
+                    putSingleHeader(entry.getKey(), entry.getValue(), newPersistentHeaders);
+                }
+                return new ThreadContextStruct(requestHeaders, responseHeaders, transientHeaders, newPersistentHeaders, isSystemContext);
             }
         }
 
@@ -606,7 +704,7 @@ private ThreadContextStruct putResponseHeaders(Map<String, Set<String>> headers)
                     newResponseHeaders.put(key, entry.getValue());
                 }
             }
-            return new ThreadContextStruct(requestHeaders, newResponseHeaders, transientHeaders, isSystemContext);
+            return new ThreadContextStruct(requestHeaders, newResponseHeaders, transientHeaders, persistentHeaders, isSystemContext);
         }
 
         private ThreadContextStruct putResponse(
@@ -643,6 +741,7 @@ private ThreadContextStruct putResponse(
                         requestHeaders,
                         responseHeaders,
                         transientHeaders,
+                        persistentHeaders,
                         isSystemContext,
                         newWarningHeaderSize
                     );
@@ -678,13 +777,28 @@ private ThreadContextStruct putResponse(
                     return this;
                 }
             }
-            return new ThreadContextStruct(requestHeaders, newResponseHeaders, transientHeaders, isSystemContext, newWarningHeaderSize);
+            return new ThreadContextStruct(
+                requestHeaders,
+                newResponseHeaders,
+                transientHeaders,
+                persistentHeaders,
+                isSystemContext,
+                newWarningHeaderSize
+            );
+        }
+
+        private ThreadContextStruct putTransient(Map<String, Object> values) {
+            Map<String, Object> newTransient = new HashMap<>(this.transientHeaders);
+            for (Map.Entry<String, Object> entry : values.entrySet()) {
+                putSingleHeader(entry.getKey(), entry.getValue(), newTransient);
+            }
+            return new ThreadContextStruct(requestHeaders, responseHeaders, newTransient, persistentHeaders, isSystemContext);
         }
 
         private ThreadContextStruct putTransient(String key, Object value) {
             Map<String, Object> newTransient = new HashMap<>(this.transientHeaders);
             putSingleHeader(key, value, newTransient);
-            return new ThreadContextStruct(requestHeaders, responseHeaders, newTransient, isSystemContext);
+            return new ThreadContextStruct(requestHeaders, responseHeaders, newTransient, persistentHeaders, isSystemContext);
         }
 
         private ThreadContextStruct copyHeaders(Iterable<Map.Entry<String, String>> headers) {
@@ -695,13 +809,15 @@ private ThreadContextStruct copyHeaders(Iterable<Map.Entry<String, String>> head
             return putHeaders(newHeaders);
         }
 
-        private void writeTo(StreamOutput out, Map<String, String> defaultHeaders) throws IOException {
+        private void writeTo(StreamOutput out, Map<String, String> defaultHeaders, Map<String, String> propagatedHeaders)
+            throws IOException {
             final Map<String, String> requestHeaders;
-            if (defaultHeaders.isEmpty()) {
+            if (defaultHeaders.isEmpty() && propagatedHeaders.isEmpty()) {
                 requestHeaders = this.requestHeaders;
             } else {
                 requestHeaders = new HashMap<>(defaultHeaders);
                 requestHeaders.putAll(this.requestHeaders);
+                requestHeaders.putAll(propagatedHeaders);
             }
 
             out.writeVInt(requestHeaders.size());
@@ -805,6 +921,11 @@ public AbstractRunnable unwrap() {
 
     private static final Collector<String, Set<String>, Set<String>> LINKED_HASH_SET_COLLECTOR = new LinkedHashSetCollector<>();
 
+    /**
+     * Collector based on a linked hash set
+     *
+     * @opensearch.internal
+     */
     private static class LinkedHashSetCollector<T> implements Collector<T, Set<T>, Set<T>> {
         @Override
         public Supplier<Set<T>> supplier() {
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContextStatePropagator.java b/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContextStatePropagator.java
new file mode 100644
index 0000000000000..b3fc79c5446db
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/ThreadContextStatePropagator.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util.concurrent;
+
+import java.util.Map;
+
+/**
+ * The propagator for {@link ThreadContext} that helps to carry-over the state from one
+ * thread to another (tasks, tracing context, etc).
+ */
+public interface ThreadContextStatePropagator {
+    /**
+     * Returns the list of transient headers that needs to be propagated from current context to new thread context.
+     * @param source current context transient headers
+     * @return the list of transient headers that needs to be propagated from current context to new thread context
+     */
+    Map<String, Object> transients(Map<String, Object> source);
+
+    /**
+     * Returns the list of request headers that needs to be propagated from current context to request.
+     * @param source current context headers
+     * @return the list of request headers that needs to be propagated from current context to request
+     */
+    Map<String, String> headers(Map<String, Object> source);
+}
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/TimedRunnable.java b/server/src/main/java/org/opensearch/common/util/concurrent/TimedRunnable.java
index 8aa14d556e8e2..2eb6657898008 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/TimedRunnable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/TimedRunnable.java
@@ -37,6 +37,8 @@
 /**
  * A class used to wrap a {@code Runnable} that allows capturing the time of the task since creation
  * through execution as well as only execution time.
+ *
+ * @opensearch.internal
  */
 class TimedRunnable extends AbstractRunnable implements WrappedRunnable {
     private final Runnable original;
@@ -105,6 +107,14 @@ long getTotalExecutionNanos() {
         return Math.max(finishTimeNanos - startTimeNanos, 1);
     }
 
+    long getWaitTimeNanos() {
+        if (startTimeNanos == -1) {
+            // There must have been an exception thrown, the total time is unknown (-1)
+            return -1;
+        }
+        return Math.max(startTimeNanos - creationTimeNanos, 1);
+    }
+
     /**
      * If the task was failed or rejected, return true.
      * Otherwise, false.
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/UncategorizedExecutionException.java b/server/src/main/java/org/opensearch/common/util/concurrent/UncategorizedExecutionException.java
index 85f8de915e339..0d0907b272b76 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/UncategorizedExecutionException.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/UncategorizedExecutionException.java
@@ -33,10 +33,15 @@
 package org.opensearch.common.util.concurrent;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown when an uncategorized error occurs.
+ *
+ * @opensearch.internal
+ */
 public class UncategorizedExecutionException extends OpenSearchException {
 
     public UncategorizedExecutionException(String msg, Throwable cause) {
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/WrappedRunnable.java b/server/src/main/java/org/opensearch/common/util/concurrent/WrappedRunnable.java
index ee4fe31ffa0b7..9763786ff4aae 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/WrappedRunnable.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/WrappedRunnable.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.common.util.concurrent;
 
+/**
+ * A wrapped runnable.
+ *
+ * @opensearch.internal
+ */
 public interface WrappedRunnable extends Runnable {
     Runnable unwrap();
 }
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/XRejectedExecutionHandler.java b/server/src/main/java/org/opensearch/common/util/concurrent/XRejectedExecutionHandler.java
index 51d30a7312f8c..c56910348c13b 100644
--- a/server/src/main/java/org/opensearch/common/util/concurrent/XRejectedExecutionHandler.java
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/XRejectedExecutionHandler.java
@@ -34,6 +34,11 @@
 
 import java.util.concurrent.RejectedExecutionHandler;
 
+/**
+ * Base handler for rejected executions.
+ *
+ * @opensearch.internal
+ */
 public interface XRejectedExecutionHandler extends RejectedExecutionHandler {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/util/concurrent/package-info.java b/server/src/main/java/org/opensearch/common/util/concurrent/package-info.java
new file mode 100644
index 0000000000000..7ccd4b6d8a6e8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/concurrent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base concurrency utilities package. */
+package org.opensearch.common.util.concurrent;
diff --git a/server/src/main/java/org/opensearch/common/util/iterable/Iterables.java b/server/src/main/java/org/opensearch/common/util/iterable/Iterables.java
index 788386e9d156c..e3f13fef37a7e 100644
--- a/server/src/main/java/org/opensearch/common/util/iterable/Iterables.java
+++ b/server/src/main/java/org/opensearch/common/util/iterable/Iterables.java
@@ -40,6 +40,11 @@
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
+/**
+ * Iterables.
+ *
+ * @opensearch.internal
+ */
 public class Iterables {
 
     public static <T> Iterable<T> concat(Iterable<T>... inputs) {
@@ -47,6 +52,11 @@ public static <T> Iterable<T> concat(Iterable<T>... inputs) {
         return new ConcatenatedIterable<>(inputs);
     }
 
+    /**
+     * Concatenated interable
+     *
+     * @opensearch.internal
+     */
     static class ConcatenatedIterable<T> implements Iterable<T> {
         private final Iterable<T>[] inputs;
 
@@ -71,6 +81,11 @@ public static <T> Iterable<T> flatten(Iterable<? extends Iterable<T>> inputs) {
         return new FlattenedIterables<>(inputs);
     }
 
+    /**
+     * A flattened iterable
+     *
+     * @opensearch.internal
+     */
     static class FlattenedIterables<T> implements Iterable<T> {
         private final Iterable<? extends Iterable<T>> inputs;
 
diff --git a/server/src/main/java/org/opensearch/common/util/iterable/package-info.java b/server/src/main/java/org/opensearch/common/util/iterable/package-info.java
new file mode 100644
index 0000000000000..5b3c307dd0ea5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/iterable/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base iterables utility package. */
+package org.opensearch.common.util.iterable;
diff --git a/server/src/main/java/org/opensearch/common/util/package-info.java b/server/src/main/java/org/opensearch/common/util/package-info.java
new file mode 100644
index 0000000000000..234c075d68d73
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/util/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Utilitiy Classes package. */
+package org.opensearch.common.util;
diff --git a/server/src/main/java/org/opensearch/common/xcontent/JsonToStringXContentParser.java b/server/src/main/java/org/opensearch/common/xcontent/JsonToStringXContentParser.java
new file mode 100644
index 0000000000000..9e81d8a7af078
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/xcontent/JsonToStringXContentParser.java
@@ -0,0 +1,266 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.xcontent;
+
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.AbstractXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.mapper.ParseContext;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.nio.CharBuffer;
+import java.util.ArrayList;
+
+/**
+ * JsonToStringParser is the main parser class to transform JSON into stringFields in a XContentParser
+ * returns XContentParser with one parent field and subfields
+ * fieldName, fieldName._value, fieldName._valueAndPath
+ * @opensearch.internal
+ */
+public class JsonToStringXContentParser extends AbstractXContentParser {
+    private final String fieldTypeName;
+    private XContentParser parser;
+
+    private ArrayList<String> valueList = new ArrayList<>();
+    private ArrayList<String> valueAndPathList = new ArrayList<>();
+    private ArrayList<String> keyList = new ArrayList<>();
+
+    private XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent);
+    private ParseContext parseContext;
+
+    private NamedXContentRegistry xContentRegistry;
+
+    private DeprecationHandler deprecationHandler;
+
+    private static final String VALUE_AND_PATH_SUFFIX = "._valueAndPath";
+    private static final String VALUE_SUFFIX = "._value";
+    private static final String DOT_SYMBOL = ".";
+    private static final String EQUAL_SYMBOL = "=";
+
+    public JsonToStringXContentParser(
+        NamedXContentRegistry xContentRegistry,
+        DeprecationHandler deprecationHandler,
+        ParseContext parseContext,
+        String fieldTypeName
+    ) throws IOException {
+        super(xContentRegistry, deprecationHandler);
+        this.parseContext = parseContext;
+        this.deprecationHandler = deprecationHandler;
+        this.xContentRegistry = xContentRegistry;
+        this.parser = parseContext.parser();
+        this.fieldTypeName = fieldTypeName;
+    }
+
+    public XContentParser parseObject() throws IOException {
+        builder.startObject();
+        StringBuilder path = new StringBuilder(fieldTypeName);
+        parseToken(path, null);
+        builder.field(this.fieldTypeName, keyList);
+        builder.field(this.fieldTypeName + VALUE_SUFFIX, valueList);
+        builder.field(this.fieldTypeName + VALUE_AND_PATH_SUFFIX, valueAndPathList);
+        builder.endObject();
+        String jString = XContentHelper.convertToJson(BytesReference.bytes(builder), false, MediaTypeRegistry.JSON);
+        return JsonXContent.jsonXContent.createParser(this.xContentRegistry, this.deprecationHandler, String.valueOf(jString));
+    }
+
+    private void parseToken(StringBuilder path, String currentFieldName) throws IOException {
+
+        while (this.parser.nextToken() != Token.END_OBJECT) {
+            if (this.parser.currentName() != null) {
+                currentFieldName = this.parser.currentName();
+            }
+            StringBuilder parsedFields = new StringBuilder();
+
+            if (this.parser.currentToken() == Token.FIELD_NAME) {
+                path.append(DOT_SYMBOL + currentFieldName);
+                this.keyList.add(currentFieldName);
+            } else if (this.parser.currentToken() == Token.START_ARRAY) {
+                parseToken(path, currentFieldName);
+                break;
+            } else if (this.parser.currentToken() == Token.END_ARRAY) {
+                // skip
+            } else if (this.parser.currentToken() == Token.START_OBJECT) {
+                parseToken(path, currentFieldName);
+                int dotIndex = path.lastIndexOf(DOT_SYMBOL);
+                if (dotIndex != -1) {
+                    path.delete(dotIndex, path.length());
+                }
+            } else {
+                if (!path.toString().contains(currentFieldName)) {
+                    path.append(DOT_SYMBOL + currentFieldName);
+                }
+                parseValue(parsedFields);
+                this.valueList.add(parsedFields.toString());
+                this.valueAndPathList.add(path + EQUAL_SYMBOL + parsedFields);
+                int dotIndex = path.lastIndexOf(DOT_SYMBOL);
+                if (dotIndex != -1) {
+                    path.delete(dotIndex, path.length());
+                }
+            }
+
+        }
+    }
+
+    private void parseValue(StringBuilder parsedFields) throws IOException {
+        switch (this.parser.currentToken()) {
+            case VALUE_BOOLEAN:
+            case VALUE_NUMBER:
+            case VALUE_STRING:
+            case VALUE_NULL:
+                parsedFields.append(this.parser.textOrNull());
+                break;
+            // Handle other token types as needed
+            case FIELD_NAME:
+            case VALUE_EMBEDDED_OBJECT:
+            case END_ARRAY:
+            case START_ARRAY:
+                break;
+            default:
+                throw new IOException("Unsupported token type [" + parser.currentToken() + "]");
+        }
+    }
+
+    @Override
+    public MediaType contentType() {
+        return MediaTypeRegistry.JSON;
+    }
+
+    @Override
+    public Token nextToken() throws IOException {
+        return this.parser.nextToken();
+    }
+
+    @Override
+    public void skipChildren() throws IOException {
+        this.parser.skipChildren();
+    }
+
+    @Override
+    public Token currentToken() {
+        return this.parser.currentToken();
+    }
+
+    @Override
+    public String currentName() throws IOException {
+        return this.parser.currentName();
+    }
+
+    @Override
+    public String text() throws IOException {
+        return this.parser.text();
+    }
+
+    @Override
+    public CharBuffer charBuffer() throws IOException {
+        return this.parser.charBuffer();
+    }
+
+    @Override
+    public Object objectText() throws IOException {
+        return this.parser.objectText();
+    }
+
+    @Override
+    public Object objectBytes() throws IOException {
+        return this.parser.objectBytes();
+    }
+
+    @Override
+    public boolean hasTextCharacters() {
+        return this.parser.hasTextCharacters();
+    }
+
+    @Override
+    public char[] textCharacters() throws IOException {
+        return this.parser.textCharacters();
+    }
+
+    @Override
+    public int textLength() throws IOException {
+        return this.parser.textLength();
+    }
+
+    @Override
+    public int textOffset() throws IOException {
+        return this.parser.textOffset();
+    }
+
+    @Override
+    public Number numberValue() throws IOException {
+        return this.parser.numberValue();
+    }
+
+    @Override
+    public NumberType numberType() throws IOException {
+        return this.parser.numberType();
+    }
+
+    @Override
+    public byte[] binaryValue() throws IOException {
+        return this.parser.binaryValue();
+    }
+
+    @Override
+    public XContentLocation getTokenLocation() {
+        return this.parser.getTokenLocation();
+    }
+
+    @Override
+    protected boolean doBooleanValue() throws IOException {
+        return this.parser.booleanValue();
+    }
+
+    @Override
+    protected short doShortValue() throws IOException {
+        return this.parser.shortValue();
+    }
+
+    @Override
+    protected int doIntValue() throws IOException {
+        return this.parser.intValue();
+    }
+
+    @Override
+    protected long doLongValue() throws IOException {
+        return this.parser.longValue();
+    }
+
+    @Override
+    protected float doFloatValue() throws IOException {
+        return this.parser.floatValue();
+    }
+
+    @Override
+    protected double doDoubleValue() throws IOException {
+        return this.parser.doubleValue();
+    }
+
+    @Override
+    protected BigInteger doBigIntegerValue() throws IOException {
+        return this.parser.bigIntegerValue();
+    }
+
+    @Override
+    public boolean isClosed() {
+        return this.parser.isClosed();
+    }
+
+    @Override
+    public void close() throws IOException {
+        this.parser.close();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/common/xcontent/LoggingDeprecationHandler.java b/server/src/main/java/org/opensearch/common/xcontent/LoggingDeprecationHandler.java
index 6ce57857515ab..06d139fa93195 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/LoggingDeprecationHandler.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/LoggingDeprecationHandler.java
@@ -32,8 +32,11 @@
 
 package org.opensearch.common.xcontent;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentLocation;
+
 import java.util.function.Supplier;
 
 /**
@@ -44,6 +47,8 @@
  * requests. It is much less appropriate when parsing responses from external
  * sources because it will report deprecated fields back to the user as
  * though the user sent them.
+ *
+ * @opensearch.internal
  */
 public class LoggingDeprecationHandler implements DeprecationHandler {
     public static final LoggingDeprecationHandler INSTANCE = new LoggingDeprecationHandler();
diff --git a/server/src/main/java/org/opensearch/common/xcontent/ParseFieldRegistry.java b/server/src/main/java/org/opensearch/common/xcontent/ParseFieldRegistry.java
index f2d1c815d70a9..b480ceaecedb6 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/ParseFieldRegistry.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/ParseFieldRegistry.java
@@ -32,9 +32,11 @@
 
 package org.opensearch.common.xcontent;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentLocation;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -42,6 +44,8 @@
 
 /**
  * Registry for looking things up using ParseField semantics.
+ *
+ * @opensearch.internal
  */
 public class ParseFieldRegistry<T> {
     private final Map<String, Tuple<ParseField, T>> registry = new HashMap<>();
diff --git a/server/src/main/java/org/opensearch/common/xcontent/StatusToXContentObject.java b/server/src/main/java/org/opensearch/common/xcontent/StatusToXContentObject.java
index 45d41bca95e5a..32e24bbbef63b 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/StatusToXContentObject.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/StatusToXContentObject.java
@@ -31,11 +31,14 @@
 
 package org.opensearch.common.xcontent;
 
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 /**
  * Objects that can both render themselves in as json/yaml/etc and can provide a {@link RestStatus} for their response. Usually should be
  * implemented by top level responses sent back to users from REST endpoints.
+ *
+ * @opensearch.internal
  */
 public interface StatusToXContentObject extends ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/common/xcontent/SuggestingErrorOnUnknown.java b/server/src/main/java/org/opensearch/common/xcontent/SuggestingErrorOnUnknown.java
index 0fd473f47acf6..1e90d21063d37 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/SuggestingErrorOnUnknown.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/SuggestingErrorOnUnknown.java
@@ -35,6 +35,7 @@
 import org.apache.lucene.search.spell.LevenshteinDistance;
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.xcontent.ErrorOnUnknown;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -42,6 +43,11 @@
 
 import static java.util.stream.Collectors.toList;
 
+/**
+ * Utility for suggesting source of errors.
+ *
+ * @opensearch.internal
+ */
 public class SuggestingErrorOnUnknown implements ErrorOnUnknown {
     @Override
     public String errorMessage(String parserName, String unknownField, Iterable<String> candidates) {
diff --git a/server/src/main/java/org/opensearch/common/xcontent/XContentHelper.java b/server/src/main/java/org/opensearch/common/xcontent/XContentHelper.java
index d0eca4228d153..798a58551457f 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/XContentHelper.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/XContentHelper.java
@@ -33,30 +33,42 @@
 package org.opensearch.common.xcontent;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.compress.Compressor;
-import org.opensearch.common.compress.CompressorFactory;
-import org.opensearch.common.xcontent.ToXContent.Params;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContent.Params;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.UncheckedIOException;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Helper for xcontent utilities.
+ *
+ * @opensearch.internal
+ */
 @SuppressWarnings("unchecked")
 public class XContentHelper {
 
     /**
      * Creates a parser based on the bytes provided
-     * @deprecated use {@link #createParser(NamedXContentRegistry, DeprecationHandler, BytesReference, XContentType)}
+     * @deprecated use {@link #createParser(NamedXContentRegistry, DeprecationHandler, BytesReference, MediaType)}
      * to avoid content type auto-detection
      */
     @Deprecated
@@ -65,7 +77,7 @@ public static XContentParser createParser(
         DeprecationHandler deprecationHandler,
         BytesReference bytes
     ) throws IOException {
-        Compressor compressor = CompressorFactory.compressor(bytes);
+        Compressor compressor = CompressorRegistry.compressor(bytes);
         if (compressor != null) {
             InputStream compressedInput = null;
             try {
@@ -73,14 +85,14 @@ public static XContentParser createParser(
                 if (compressedInput.markSupported() == false) {
                     compressedInput = new BufferedInputStream(compressedInput);
                 }
-                final XContentType contentType = XContentFactory.xContentType(compressedInput);
-                return XContentFactory.xContent(contentType).createParser(xContentRegistry, deprecationHandler, compressedInput);
+                final MediaType contentType = MediaTypeRegistry.xContentType(compressedInput);
+                return contentType.xContent().createParser(xContentRegistry, deprecationHandler, compressedInput);
             } catch (Exception e) {
                 if (compressedInput != null) compressedInput.close();
                 throw e;
             }
         } else {
-            return XContentFactory.xContent(xContentType(bytes)).createParser(xContentRegistry, deprecationHandler, bytes.streamInput());
+            return MediaTypeRegistry.xContentType(bytes).xContent().createParser(xContentRegistry, deprecationHandler, bytes.streamInput());
         }
     }
 
@@ -91,10 +103,10 @@ public static XContentParser createParser(
         NamedXContentRegistry xContentRegistry,
         DeprecationHandler deprecationHandler,
         BytesReference bytes,
-        XContentType xContentType
+        MediaType mediaType
     ) throws IOException {
-        Objects.requireNonNull(xContentType);
-        Compressor compressor = CompressorFactory.compressor(bytes);
+        Objects.requireNonNull(mediaType);
+        Compressor compressor = CompressorRegistry.compressor(bytes);
         if (compressor != null) {
             InputStream compressedInput = null;
             try {
@@ -102,7 +114,7 @@ public static XContentParser createParser(
                 if (compressedInput.markSupported() == false) {
                     compressedInput = new BufferedInputStream(compressedInput);
                 }
-                return XContentFactory.xContent(xContentType).createParser(xContentRegistry, deprecationHandler, compressedInput);
+                return mediaType.xContent().createParser(xContentRegistry, deprecationHandler, compressedInput);
             } catch (Exception e) {
                 if (compressedInput != null) compressedInput.close();
                 throw e;
@@ -110,16 +122,16 @@ public static XContentParser createParser(
         } else {
             if (bytes instanceof BytesArray) {
                 final BytesArray array = (BytesArray) bytes;
-                return xContentType.xContent()
+                return mediaType.xContent()
                     .createParser(xContentRegistry, deprecationHandler, array.array(), array.offset(), array.length());
             }
-            return xContentType.xContent().createParser(xContentRegistry, deprecationHandler, bytes.streamInput());
+            return mediaType.xContent().createParser(xContentRegistry, deprecationHandler, bytes.streamInput());
         }
     }
 
     /**
      * Converts the given bytes into a map that is optionally ordered.
-     * @deprecated this method relies on auto-detection of content type. Use {@link #convertToMap(BytesReference, boolean, XContentType)}
+     * @deprecated this method relies on auto-detection of content type. Use {@link #convertToMap(BytesReference, boolean, MediaType)}
      *             instead with the proper {@link XContentType}
      */
     @Deprecated
@@ -128,15 +140,30 @@ public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReferen
         return convertToMap(bytes, ordered, null);
     }
 
+    /**
+     * Converts the given bytes into a map that is optionally ordered. The provided {@link XContentType} must be non-null.
+     *
+     * @deprecated use {@link #convertToMap(BytesReference, boolean, MediaType)} instead
+     */
+    @Deprecated
+    public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReference bytes, boolean ordered, XContentType xContentType) {
+        if (Objects.isNull(xContentType) == false && xContentType instanceof XContentType == false) {
+            throw new IllegalArgumentException(
+                "XContentHelper.convertToMap does not support media type [" + xContentType.getClass().getName() + "]"
+            );
+        }
+        return (Tuple<XContentType, Map<String, Object>>) convertToMap(bytes, ordered, (MediaType) xContentType);
+    }
+
     /**
      * Converts the given bytes into a map that is optionally ordered. The provided {@link XContentType} must be non-null.
      */
-    public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReference bytes, boolean ordered, XContentType xContentType)
+    public static Tuple<? extends MediaType, Map<String, Object>> convertToMap(BytesReference bytes, boolean ordered, MediaType mediaType)
         throws OpenSearchParseException {
         try {
-            final XContentType contentType;
+            final MediaType contentType;
             InputStream input;
-            Compressor compressor = CompressorFactory.compressor(bytes);
+            Compressor compressor = CompressorRegistry.compressor(bytes);
             if (compressor != null) {
                 InputStream compressedStreamInput = compressor.threadLocalInputStream(bytes.streamInput());
                 if (compressedStreamInput.markSupported() == false) {
@@ -148,20 +175,14 @@ public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReferen
                 final byte[] raw = arr.array();
                 final int offset = arr.offset();
                 final int length = arr.length();
-                contentType = xContentType != null ? xContentType : XContentFactory.xContentType(raw, offset, length);
-                return new Tuple<>(
-                    Objects.requireNonNull(contentType),
-                    convertToMap(XContentFactory.xContent(contentType), raw, offset, length, ordered)
-                );
+                contentType = mediaType != null ? mediaType : MediaTypeRegistry.mediaTypeFromBytes(raw, offset, length);
+                return new Tuple<>(Objects.requireNonNull(contentType), convertToMap(contentType.xContent(), raw, offset, length, ordered));
             } else {
                 input = bytes.streamInput();
             }
             try (InputStream stream = input) {
-                contentType = xContentType != null ? xContentType : XContentFactory.xContentType(stream);
-                return new Tuple<>(
-                    Objects.requireNonNull(contentType),
-                    convertToMap(XContentFactory.xContent(contentType), stream, ordered)
-                );
+                contentType = mediaType != null ? mediaType : MediaTypeRegistry.xContentType(stream);
+                return new Tuple<>(Objects.requireNonNull(contentType), convertToMap(contentType.xContent(), stream, ordered));
             }
         } catch (IOException e) {
             throw new OpenSearchParseException("Failed to parse content to map", e);
@@ -235,11 +256,11 @@ public static String convertToJson(BytesReference bytes, boolean reformatJson) t
 
     @Deprecated
     public static String convertToJson(BytesReference bytes, boolean reformatJson, boolean prettyPrint) throws IOException {
-        return convertToJson(bytes, reformatJson, prettyPrint, XContentFactory.xContentType(bytes.toBytesRef().bytes));
+        return convertToJson(bytes, reformatJson, prettyPrint, MediaTypeRegistry.xContent(bytes.toBytesRef().bytes));
     }
 
-    public static String convertToJson(BytesReference bytes, boolean reformatJson, XContentType xContentType) throws IOException {
-        return convertToJson(bytes, reformatJson, false, xContentType);
+    public static String convertToJson(BytesReference bytes, boolean reformatJson, MediaType mediaType) throws IOException {
+        return convertToJson(bytes, reformatJson, false, mediaType);
     }
 
     /**
@@ -252,13 +273,27 @@ public static String convertToJson(BytesReference bytes, boolean reformatJson, X
      * @throws IOException if the reformatting fails, e.g. because the JSON is not well-formed
      */
     public static String stripWhitespace(String json) throws IOException {
-        return convertToJson(new BytesArray(json), true, XContentType.JSON);
+        return convertToJson(new BytesArray(json), true, MediaTypeRegistry.JSON);
     }
 
+    /**
+     * Converts the XContentType to a json string
+     *
+     * @deprecated use {@link #convertToJson(BytesReference, boolean, boolean, MediaType)} instead
+     */
+    @Deprecated
     public static String convertToJson(BytesReference bytes, boolean reformatJson, boolean prettyPrint, XContentType xContentType)
         throws IOException {
-        Objects.requireNonNull(xContentType);
-        if (xContentType == XContentType.JSON && !reformatJson) {
+        return convertToJson(bytes, reformatJson, prettyPrint, (MediaType) xContentType);
+    }
+
+    /**
+     * Converts the given {@link MediaType} to a json string
+     */
+    public static String convertToJson(BytesReference bytes, boolean reformatJson, boolean prettyPrint, MediaType mediaType)
+        throws IOException {
+        Objects.requireNonNull(mediaType);
+        if (mediaType == MediaTypeRegistry.JSON && !reformatJson) {
             return bytes.utf8ToString();
         }
 
@@ -266,7 +301,7 @@ public static String convertToJson(BytesReference bytes, boolean reformatJson, b
         if (bytes instanceof BytesArray) {
             final BytesArray array = (BytesArray) bytes;
             try (
-                XContentParser parser = XContentFactory.xContent(xContentType)
+                XContentParser parser = mediaType.xContent()
                     .createParser(
                         NamedXContentRegistry.EMPTY,
                         DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -280,7 +315,7 @@ public static String convertToJson(BytesReference bytes, boolean reformatJson, b
         } else {
             try (
                 InputStream stream = bytes.streamInput();
-                XContentParser parser = XContentFactory.xContent(xContentType)
+                XContentParser parser = mediaType.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, stream)
             ) {
                 return toJsonString(prettyPrint, parser);
@@ -295,7 +330,7 @@ private static String toJsonString(boolean prettyPrint, XContentParser parser) t
             builder.prettyPrint();
         }
         builder.copyCurrentStructure(parser);
-        return Strings.toString(builder);
+        return builder.toString();
     }
 
     /**
@@ -416,7 +451,7 @@ private static boolean allListValuesAreMapsOfOne(List list) {
      */
     @Deprecated
     public static void writeRawField(String field, BytesReference source, XContentBuilder builder, Params params) throws IOException {
-        Compressor compressor = CompressorFactory.compressor(source);
+        Compressor compressor = CompressorRegistry.compressor(source);
         if (compressor != null) {
             try (InputStream compressedStreamInput = compressor.threadLocalInputStream(source.streamInput())) {
                 builder.rawField(field, compressedStreamInput);
@@ -430,12 +465,12 @@ public static void writeRawField(String field, BytesReference source, XContentBu
 
     /**
      * Writes a "raw" (bytes) field, handling cases where the bytes are compressed, and tries to optimize writing using
-     * {@link XContentBuilder#rawField(String, InputStream, XContentType)}.
+     * {@link XContentBuilder#rawField(String, InputStream, MediaType)}.
      */
     public static void writeRawField(String field, BytesReference source, XContentType xContentType, XContentBuilder builder, Params params)
         throws IOException {
         Objects.requireNonNull(xContentType);
-        Compressor compressor = CompressorFactory.compressor(source);
+        Compressor compressor = CompressorRegistry.compressor(source);
         if (compressor != null) {
             try (InputStream compressedStreamInput = compressor.threadLocalInputStream(source.streamInput())) {
                 builder.rawField(field, compressedStreamInput, xContentType);
@@ -452,51 +487,9 @@ public static void writeRawField(String field, BytesReference source, XContentTy
      * {@link XContentType}. Wraps the output into a new anonymous object according to the value returned
      * by the {@link ToXContent#isFragment()} method returns.
      */
-    public static BytesReference toXContent(ToXContent toXContent, XContentType xContentType, boolean humanReadable) throws IOException {
-        return toXContent(toXContent, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
-    }
-
-    /**
-     * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
-     * {@link XContentType}. Wraps the output into a new anonymous object according to the value returned
-     * by the {@link ToXContent#isFragment()} method returns.
-     */
-    public static BytesReference toXContent(ToXContent toXContent, XContentType xContentType, Params params, boolean humanReadable)
-        throws IOException {
-        try (XContentBuilder builder = XContentBuilder.builder(xContentType.xContent())) {
-            builder.humanReadable(humanReadable);
-            if (toXContent.isFragment()) {
-                builder.startObject();
-            }
-            toXContent.toXContent(builder, params);
-            if (toXContent.isFragment()) {
-                builder.endObject();
-            }
-            return BytesReference.bytes(builder);
-        }
-    }
-
-    /**
-     * Guesses the content type based on the provided bytes.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
     @Deprecated
-    public static XContentType xContentType(BytesReference bytes) {
-        if (bytes instanceof BytesArray) {
-            final BytesArray array = (BytesArray) bytes;
-            return XContentFactory.xContentType(array.array(), array.offset(), array.length());
-        }
-        try {
-            final InputStream inputStream = bytes.streamInput();
-            assert inputStream.markSupported();
-            return XContentFactory.xContentType(inputStream);
-        } catch (IOException e) {
-            assert false : "Should not happen, we're just reading bytes from memory";
-            throw new UncheckedIOException(e);
-        }
+    public static BytesReference toXContent(ToXContent toXContent, XContentType xContentType, boolean humanReadable) throws IOException {
+        return org.opensearch.core.xcontent.XContentHelper.toXContent(toXContent, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/xcontent/XContentOpenSearchExtension.java b/server/src/main/java/org/opensearch/common/xcontent/XContentOpenSearchExtension.java
index 214b35c13c7cd..a02d338f1ddcb 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/XContentOpenSearchExtension.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/XContentOpenSearchExtension.java
@@ -33,10 +33,12 @@
 package org.opensearch.common.xcontent;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilderExtension;
 import org.opensearch.script.JodaCompatibleZonedDateTime;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
@@ -73,6 +75,8 @@
  * SPI extensions for OpenSearch-specific classes (like the Lucene or Joda
  * dependency classes) that need to be encoded by {@link XContentBuilder} in a
  * specific way.
+ *
+ * @opensearch.internal
  */
 public class XContentOpenSearchExtension implements XContentBuilderExtension {
 
diff --git a/server/src/main/java/org/opensearch/common/xcontent/package-info.java b/server/src/main/java/org/opensearch/common/xcontent/package-info.java
new file mode 100644
index 0000000000000..5f820fe4d973f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/xcontent/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base XContent parsing and building utiilty class package. */
+package org.opensearch.common.xcontent;
diff --git a/server/src/main/java/org/opensearch/common/xcontent/support/XContentMapValues.java b/server/src/main/java/org/opensearch/common/xcontent/support/XContentMapValues.java
index 5eb4b782b3f4a..adfa871cbfcbe 100644
--- a/server/src/main/java/org/opensearch/common/xcontent/support/XContentMapValues.java
+++ b/server/src/main/java/org/opensearch/common/xcontent/support/XContentMapValues.java
@@ -39,9 +39,9 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Numbers;
-import org.opensearch.common.Strings;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -50,6 +50,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Map values for xcontent parsing.
+ *
+ * @opensearch.internal
+ */
 public class XContentMapValues {
 
     /**
diff --git a/server/src/main/java/org/opensearch/common/xcontent/support/package-info.java b/server/src/main/java/org/opensearch/common/xcontent/support/package-info.java
new file mode 100644
index 0000000000000..021ccf0a07a98
--- /dev/null
+++ b/server/src/main/java/org/opensearch/common/xcontent/support/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** XContent specific support classes package. */
+package org.opensearch.common.xcontent.support;
diff --git a/server/src/main/java/org/opensearch/crypto/CryptoHandlerRegistry.java b/server/src/main/java/org/opensearch/crypto/CryptoHandlerRegistry.java
new file mode 100644
index 0000000000000..0a14331be35f7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/crypto/CryptoHandlerRegistry.java
@@ -0,0 +1,168 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.MasterKeyProvider;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.CryptoKeyProviderPlugin;
+import org.opensearch.plugins.CryptoPlugin;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * During node bootstrap, installed key provider extensions responsible for generating data keys are loaded.
+ * Crypto factories against the respective KP plugins are cached. A crypto factory is used to register crypto
+ * handler against an {@link org.opensearch.common.blobstore.EncryptedBlobStore}
+ */
+public class CryptoHandlerRegistry {
+    private static final Logger logger = LogManager.getLogger(CryptoHandlerRegistry.class);
+    // Package private for tests
+    SetOnce<Map<String, CryptoKeyProviderPlugin>> registry = new SetOnce<>();
+
+    // Package private for tests
+    SetOnce<CryptoPlugin> cryptoHandlerPlugin = new SetOnce<>();
+    private final Map<CryptoMetadata, CryptoHandler> registeredCryptoHandlers = new HashMap<>();
+
+    private static volatile CryptoHandlerRegistry instance;
+    private static final Object lock = new Object();
+
+    /**
+     * Initializes the registry with crypto factories for the installed crypto key providers.
+     *
+     * @param cryptoPlugins The list of installed crypto key provider plugins.
+     * @param settings Crypto settings.
+     */
+    protected CryptoHandlerRegistry(
+        List<CryptoPlugin> cryptoPlugins,
+        List<CryptoKeyProviderPlugin> cryptoKeyProviderPlugins,
+        Settings settings
+    ) {
+        if (cryptoPlugins == null || cryptoPlugins.size() == 0) {
+            return;
+        }
+        if (cryptoPlugins.size() > 1) {
+            // We can remove this to support multiple implementations in future if needed.
+            throw new IllegalStateException("More than 1 implementation of crypto plugin found.");
+        }
+
+        cryptoHandlerPlugin.set(cryptoPlugins.get(0));
+        registry.set(loadCryptoFactories(cryptoKeyProviderPlugins));
+    }
+
+    public static CryptoHandlerRegistry getInstance() {
+        return instance;
+    }
+
+    public static CryptoHandlerRegistry initRegistry(
+        List<CryptoPlugin> cryptoPlugins,
+        List<CryptoKeyProviderPlugin> cryptoKeyProviderPlugins,
+        Settings settings
+    ) {
+        CryptoHandlerRegistry curInstance = instance;
+        if (curInstance == null) {
+            synchronized (lock) {
+                curInstance = instance;
+                if (curInstance == null) {
+                    instance = curInstance = new CryptoHandlerRegistry(cryptoPlugins, cryptoKeyProviderPlugins, settings);
+                }
+            }
+        }
+        return curInstance;
+    }
+
+    // For tests
+    protected Map<String, CryptoKeyProviderPlugin> loadCryptoFactories(List<CryptoKeyProviderPlugin> cryptoKPPlugins) {
+        Map<String, CryptoKeyProviderPlugin> cryptoFactories = new HashMap<>();
+        for (CryptoKeyProviderPlugin cryptoKPPlugin : cryptoKPPlugins) {
+            if (cryptoFactories.containsKey(cryptoKPPlugin.type())) {
+                throw new IllegalArgumentException("Crypto plugin key provider type [" + cryptoKPPlugin.type() + "] is already registered");
+            }
+            cryptoFactories.put(cryptoKPPlugin.type(), cryptoKPPlugin);
+        }
+
+        return Map.copyOf(cryptoFactories);
+    }
+
+    /**
+     * Retrieves the crypto factory associated with the given key provider type .
+     *
+     * @param keyProviderType The unique provider type for which the factory is to be fetched.
+     * @return The crypto factory used to create {@link CryptoHandler}
+     *         instances in a {@link org.opensearch.common.blobstore.EncryptedBlobStore}.
+     * @throws IllegalStateException If the crypto registry is not yet loaded.
+     */
+    public CryptoKeyProviderPlugin getCryptoKeyProviderPlugin(String keyProviderType) {
+        if (registry.get() == null) {
+            throw new IllegalStateException("Crypto registry is not yet loaded");
+        }
+        return Objects.requireNonNull(registry.get()).get(keyProviderType);
+    }
+
+    /**
+     * Fetches the cached crypto manager for the provided crypto metadata or creates a new one if not found.
+     * If the key provider is not installed, it throws a {@link CryptoRegistryException}.
+     *
+     * @param cryptoMetadata The crypto metadata for which the key provider is to be created.
+     * @return The crypto manager for performing encrypt/decrypt operations.
+     * @throws CryptoRegistryException If the key provider is not installed or there is an error during crypto manager creation.
+     */
+    public CryptoHandler<?, ?> fetchCryptoHandler(CryptoMetadata cryptoMetadata) {
+        CryptoHandler<?, ?> cryptoHandler = registeredCryptoHandlers.get(cryptoMetadata);
+        if (cryptoHandler == null) {
+            synchronized (registeredCryptoHandlers) {
+                cryptoHandler = registeredCryptoHandlers.get(cryptoMetadata);
+                if (cryptoHandler == null) {
+                    Runnable onClose = () -> {
+                        synchronized (registeredCryptoHandlers) {
+                            registeredCryptoHandlers.remove(cryptoMetadata);
+                        }
+                    };
+                    cryptoHandler = createCryptoHandler(cryptoMetadata, onClose);
+                    registeredCryptoHandlers.put(cryptoMetadata, cryptoHandler);
+                }
+            }
+        }
+        return cryptoHandler;
+    }
+
+    private CryptoHandler<?, ?> createCryptoHandler(CryptoMetadata cryptoMetadata, Runnable onClose) {
+        logger.debug("creating crypto client [{}][{}]", cryptoMetadata.keyProviderType(), cryptoMetadata.keyProviderName());
+        CryptoKeyProviderPlugin keyProviderPlugin = getCryptoKeyProviderPlugin(cryptoMetadata.keyProviderType());
+        if (keyProviderPlugin == null) {
+            throw new CryptoRegistryException(cryptoMetadata.keyProviderName(), cryptoMetadata.keyProviderType());
+        }
+
+        try {
+            MasterKeyProvider masterKeyProvider = keyProviderPlugin.createKeyProvider(cryptoMetadata);
+            return Objects.requireNonNull(cryptoHandlerPlugin.get())
+                .getOrCreateCryptoHandler(masterKeyProvider, cryptoMetadata.keyProviderName(), cryptoMetadata.keyProviderType(), onClose);
+
+        } catch (Exception e) {
+            logger.warn(
+                new ParameterizedMessage(
+                    "failed to create crypto manager of name [{}] and type [{}]",
+                    cryptoMetadata.keyProviderName(),
+                    cryptoMetadata.keyProviderType()
+                ),
+                e
+            );
+            throw new CryptoRegistryException(cryptoMetadata.keyProviderName(), cryptoMetadata.keyProviderType(), e);
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/crypto/CryptoRegistryException.java b/server/src/main/java/org/opensearch/crypto/CryptoRegistryException.java
new file mode 100644
index 0000000000000..a1b065649079d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/crypto/CryptoRegistryException.java
@@ -0,0 +1,127 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * Thrown when crypto manager creation or retrieval fails.
+ *
+ * @opensearch.internal
+ */
+public class CryptoRegistryException extends OpenSearchException {
+    private final String name;
+    private final String type;
+    private final RestStatus restStatus;
+
+    /**
+     * Constructs a new CryptoRegistryException with the given client name and client type.
+     *
+     * @param clientName The name of the client for which the crypto registry is missing.
+     * @param clientType The type of the client for which the crypto registry is missing.
+     */
+    public CryptoRegistryException(String clientName, String clientType) {
+        super("[Missing crypto registry for client name : " + clientName + " of type " + clientType + " ]");
+        this.name = clientName;
+        this.type = clientType;
+        this.restStatus = RestStatus.NOT_FOUND;
+    }
+
+    /**
+     * Constructs a new CryptoRegistryException with the given client name, client type, and a cause.
+     *
+     * @param clientName The name of the client that caused the exception.
+     * @param clientType The type of the client that caused the exception.
+     * @param cause      The cause of the exception, which could be another throwable.
+     */
+    public CryptoRegistryException(String clientName, String clientType, Throwable cause) {
+        super("[Client name : " + clientName + " Type " + clientType + " ]", cause);
+        this.name = clientName;
+        this.type = clientType;
+        if (cause instanceof IllegalArgumentException) {
+            this.restStatus = RestStatus.BAD_REQUEST;
+        } else {
+            this.restStatus = RestStatus.INTERNAL_SERVER_ERROR;
+        }
+    }
+
+    /**
+     * Constructs a new CryptoRegistryException with the given client name, client type, and a custom message.
+     *
+     * @param clientName The name of the client that caused the exception.
+     * @param clientType The type of the client that caused the exception.
+     * @param msg        A custom message to be included in the exception.
+     */
+    public CryptoRegistryException(String clientName, String clientType, String msg) {
+        super("[ " + msg + " Client name : " + clientName + " type " + clientType + " ] ");
+        this.name = clientName;
+        this.type = clientType;
+        this.restStatus = RestStatus.INTERNAL_SERVER_ERROR;
+    }
+
+    /**
+     * Get the HTTP status associated with this exception.
+     *
+     * @return The HTTP status code representing the nature of the exception.
+     */
+    @Override
+    public RestStatus status() {
+        return restStatus;
+    }
+
+    /**
+     * Get the name of the client associated with this exception.
+     *
+     * @return The name of the client for which the exception was raised.
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Get the type of the client associated with this exception.
+     *
+     * @return The type of the client for which the exception was raised.
+     */
+    public String getType() {
+        return type;
+    }
+
+    /**
+     * Constructs a new CryptoRegistryException by deserializing it from the provided input stream.
+     *
+     * @param in The input stream containing the serialized exception data.
+     * @throws IOException If an I/O error occurs while reading from the input stream.
+     */
+    public CryptoRegistryException(StreamInput in) throws IOException {
+        super(in);
+        this.name = in.readString();
+        this.type = in.readString();
+        this.restStatus = RestStatus.fromCode(in.readInt());
+    }
+
+    /**
+     * Write the exception data to the provided output stream for serialization.
+     *
+     * @param out The output stream to which the exception data should be written.
+     * @throws IOException If an I/O error occurs while writing to the output stream.
+     */
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(name);
+        out.writeString(type);
+        out.writeInt(restStatus.getStatus());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/crypto/package-info.java b/server/src/main/java/org/opensearch/crypto/package-info.java
new file mode 100644
index 0000000000000..742960ac1cf97
--- /dev/null
+++ b/server/src/main/java/org/opensearch/crypto/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package for crypto client abstractions and exceptions.
+ */
+package org.opensearch.crypto;
diff --git a/server/src/main/java/org/opensearch/discovery/AckClusterStatePublishResponseHandler.java b/server/src/main/java/org/opensearch/discovery/AckClusterStatePublishResponseHandler.java
index 161450308b384..68dae7966b486 100644
--- a/server/src/main/java/org/opensearch/discovery/AckClusterStatePublishResponseHandler.java
+++ b/server/src/main/java/org/opensearch/discovery/AckClusterStatePublishResponseHandler.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.discovery;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.cluster.node.DiscoveryNode;
 
@@ -42,6 +42,8 @@
  * Allows to wait for all nodes to reply to the publish of a new cluster state
  * and notifies the {@link org.opensearch.discovery.Discovery.AckListener}
  * so that the cluster state update can be acknowledged
+ *
+ * @opensearch.internal
  */
 public class AckClusterStatePublishResponseHandler extends BlockingClusterStatePublishResponseHandler {
 
@@ -53,11 +55,11 @@ public class AckClusterStatePublishResponseHandler extends BlockingClusterStateP
      * Creates a new AckClusterStatePublishResponseHandler
      * @param publishingToNodes the set of nodes to which the cluster state will be published and should respond
      * @param ackListener the {@link org.opensearch.discovery.Discovery.AckListener} to notify for each response
-     *                    gotten from non master nodes
+     *                    gotten from non cluster-manager nodes
      */
     public AckClusterStatePublishResponseHandler(Set<DiscoveryNode> publishingToNodes, Discovery.AckListener ackListener) {
-        // Don't count the master as acknowledged, because it's not done yet
-        // otherwise we might end up with all the nodes but the master holding the latest cluster state
+        // Don't count the cluster-manager as acknowledged, because it's not done yet
+        // otherwise we might end up with all the nodes but the cluster-manager holding the latest cluster state
         super(publishingToNodes);
         this.ackListener = ackListener;
     }
diff --git a/server/src/main/java/org/opensearch/discovery/BlockingClusterStatePublishResponseHandler.java b/server/src/main/java/org/opensearch/discovery/BlockingClusterStatePublishResponseHandler.java
index c0cd390b66f78..daed425034087 100644
--- a/server/src/main/java/org/opensearch/discovery/BlockingClusterStatePublishResponseHandler.java
+++ b/server/src/main/java/org/opensearch/discovery/BlockingClusterStatePublishResponseHandler.java
@@ -41,8 +41,10 @@
 import java.util.concurrent.TimeUnit;
 
 /**
- * Handles responses obtained when publishing a new cluster state from master to all non master nodes.
- * Allows to await a reply from all non master nodes, up to a timeout
+ * Handles responses obtained when publishing a new cluster state from cluster-manager to all non cluster-manager nodes.
+ * Allows to await a reply from all non cluster-manager nodes, up to a timeout
+ *
+ * @opensearch.internal
  */
 public class BlockingClusterStatePublishResponseHandler {
 
@@ -62,7 +64,7 @@ public BlockingClusterStatePublishResponseHandler(Set<DiscoveryNode> publishingT
     }
 
     /**
-     * Called for each response obtained from non master nodes
+     * Called for each response obtained from non cluster-manager nodes
      *
      * @param node the node that replied to the publish event
      */
@@ -73,7 +75,7 @@ public void onResponse(DiscoveryNode node) {
     }
 
     /**
-     * Called for each failure obtained from non master nodes
+     * Called for each failure obtained from non cluster-manager nodes
      * @param node the node that replied to the publish event
      */
     public void onFailure(DiscoveryNode node, Exception e) {
@@ -85,7 +87,7 @@ public void onFailure(DiscoveryNode node, Exception e) {
     }
 
     /**
-     * Allows to wait for all non master nodes to reply to the publish event up to a timeout
+     * Allows to wait for all non cluster-manager nodes to reply to the publish event up to a timeout
      * @param timeout the timeout
      * @return true if the timeout expired or not, false otherwise
      */
diff --git a/server/src/main/java/org/opensearch/discovery/ClusterManagerNotDiscoveredException.java b/server/src/main/java/org/opensearch/discovery/ClusterManagerNotDiscoveredException.java
new file mode 100644
index 0000000000000..7ee11df3d4e6d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/discovery/ClusterManagerNotDiscoveredException.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * Exception when the cluster-manager is not discovered
+ *
+ * @opensearch.internal
+ */
+public class ClusterManagerNotDiscoveredException extends OpenSearchException {
+
+    public ClusterManagerNotDiscoveredException() {
+        super("");
+    }
+
+    public ClusterManagerNotDiscoveredException(Throwable cause) {
+        super(cause);
+    }
+
+    public ClusterManagerNotDiscoveredException(String message) {
+        super(message);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.SERVICE_UNAVAILABLE;
+    }
+
+    public ClusterManagerNotDiscoveredException(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/discovery/Discovery.java b/server/src/main/java/org/opensearch/discovery/Discovery.java
index ac5028f6dfc51..9d6807b6522c9 100644
--- a/server/src/main/java/org/opensearch/discovery/Discovery.java
+++ b/server/src/main/java/org/opensearch/discovery/Discovery.java
@@ -33,12 +33,14 @@
 package org.opensearch.discovery;
 
 import org.opensearch.cluster.coordination.ClusterStatePublisher;
-import org.opensearch.common.component.LifecycleComponent;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 
 /**
  * A pluggable module allowing to implement discovery of other nodes, publishing of the cluster
- * state to all nodes, electing a master of the cluster that raises cluster state change
+ * state to all nodes, electing a cluster-manager of the cluster that raises cluster state change
  * events.
+ *
+ * @opensearch.internal
  */
 public interface Discovery extends LifecycleComponent, ClusterStatePublisher {
 
diff --git a/server/src/main/java/org/opensearch/discovery/DiscoveryModule.java b/server/src/main/java/org/opensearch/discovery/DiscoveryModule.java
index 427615da7e4d0..288371aa240a0 100644
--- a/server/src/main/java/org/opensearch/discovery/DiscoveryModule.java
+++ b/server/src/main/java/org/opensearch/discovery/DiscoveryModule.java
@@ -37,21 +37,23 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.Coordinator;
 import org.opensearch.cluster.coordination.ElectionStrategy;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterApplier;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.monitor.NodeHealthService;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.plugins.DiscoveryPlugin;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -75,6 +77,8 @@
 
 /**
  * A module for loading classes for node discovery.
+ *
+ * @opensearch.internal
  */
 public class DiscoveryModule {
     private static final Logger logger = LogManager.getLogger(DiscoveryModule.class);
@@ -119,7 +123,7 @@ public DiscoveryModule(
         TransportService transportService,
         NamedWriteableRegistry namedWriteableRegistry,
         NetworkService networkService,
-        MasterService masterService,
+        ClusterManagerService clusterManagerService,
         ClusterApplier clusterApplier,
         ClusterSettings clusterSettings,
         List<DiscoveryPlugin> plugins,
@@ -127,7 +131,9 @@ public DiscoveryModule(
         Path configFile,
         GatewayMetaState gatewayMetaState,
         RerouteService rerouteService,
-        NodeHealthService nodeHealthService
+        NodeHealthService nodeHealthService,
+        PersistedStateRegistry persistedStateRegistry,
+        RemoteStoreNodeService remoteStoreNodeService
     ) {
         final Collection<BiConsumer<DiscoveryNode, ClusterState>> joinValidators = new ArrayList<>();
         final Map<String, Supplier<SeedHostsProvider>> hostProviders = new HashMap<>();
@@ -195,7 +201,7 @@ public DiscoveryModule(
                 transportService,
                 namedWriteableRegistry,
                 allocationService,
-                masterService,
+                clusterManagerService,
                 gatewayMetaState::getPersistedState,
                 seedHostsProvider,
                 clusterApplier,
@@ -203,7 +209,9 @@ public DiscoveryModule(
                 new Random(Randomness.get().nextLong()),
                 rerouteService,
                 electionStrategy,
-                nodeHealthService
+                nodeHealthService,
+                persistedStateRegistry,
+                remoteStoreNodeService
             );
         } else {
             throw new IllegalArgumentException("Unknown discovery type [" + discoveryType + "]");
diff --git a/server/src/main/java/org/opensearch/discovery/DiscoveryStats.java b/server/src/main/java/org/opensearch/discovery/DiscoveryStats.java
index e480799c9f7c4..665ecf77d7aa7 100644
--- a/server/src/main/java/org/opensearch/discovery/DiscoveryStats.java
+++ b/server/src/main/java/org/opensearch/discovery/DiscoveryStats.java
@@ -32,16 +32,21 @@
 
 package org.opensearch.discovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.cluster.coordination.PendingClusterStateStats;
 import org.opensearch.cluster.coordination.PublishClusterStateStats;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stores discovery stats
+ *
+ * @opensearch.internal
+ */
 public class DiscoveryStats implements Writeable, ToXContentFragment {
 
     private final PendingClusterStateStats queueStats;
diff --git a/server/src/main/java/org/opensearch/discovery/FileBasedSeedHostsProvider.java b/server/src/main/java/org/opensearch/discovery/FileBasedSeedHostsProvider.java
index c6cd8411afc91..3159733336057 100644
--- a/server/src/main/java/org/opensearch/discovery/FileBasedSeedHostsProvider.java
+++ b/server/src/main/java/org/opensearch/discovery/FileBasedSeedHostsProvider.java
@@ -35,7 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -57,6 +57,8 @@
  * 67.81.244.10
  * 67.81.244.11:9305
  * 67.81.244.15:9400
+ *
+ * @opensearch.internal
  */
 public class FileBasedSeedHostsProvider implements SeedHostsProvider {
 
diff --git a/server/src/main/java/org/opensearch/discovery/HandshakingTransportAddressConnector.java b/server/src/main/java/org/opensearch/discovery/HandshakingTransportAddressConnector.java
index 906e28cbb6b51..c41f170bef65a 100644
--- a/server/src/main/java/org/opensearch/discovery/HandshakingTransportAddressConnector.java
+++ b/server/src/main/java/org/opensearch/discovery/HandshakingTransportAddressConnector.java
@@ -36,17 +36,17 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.NotifyOnceListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.PeerFinder.TransportAddressConnector;
 import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.ConnectionProfile;
@@ -57,6 +57,11 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 
+/**
+ * Connector for transport handshake
+ *
+ * @opensearch.internal
+ */
 public class HandshakingTransportAddressConnector implements TransportAddressConnector {
 
     private static final Logger logger = LogManager.getLogger(HandshakingTransportAddressConnector.class);
@@ -136,8 +141,10 @@ protected void innerOnResponse(DiscoveryNode remoteNode) {
 
                                         if (remoteNode.equals(transportService.getLocalNode())) {
                                             listener.onFailure(new ConnectTransportException(remoteNode, "local node found"));
-                                        } else if (remoteNode.isMasterNode() == false) {
-                                            listener.onFailure(new ConnectTransportException(remoteNode, "non-master-eligible node found"));
+                                        } else if (remoteNode.isClusterManagerNode() == false) {
+                                            listener.onFailure(
+                                                new ConnectTransportException(remoteNode, "non-cluster-manager-eligible node found")
+                                            );
                                         } else {
                                             transportService.connectToNode(remoteNode, new ActionListener<Void>() {
                                                 @Override
@@ -153,7 +160,8 @@ public void onResponse(Void ignored) {
                                                 @Override
                                                 public void onFailure(Exception e) {
                                                     // we opened a connection and successfully performed a handshake, so we're definitely
-                                                    // talking to a master-eligible node with a matching cluster name and a good version,
+                                                    // talking to a cluster-manager-eligible node with a matching cluster name and a good
+                                                    // version,
                                                     // but the attempt to open a full connection to its publish address failed; a common
                                                     // reason is that the remote node is listening on 0.0.0.0 but has made an inappropriate
                                                     // choice for its publish address.
diff --git a/server/src/main/java/org/opensearch/discovery/InitializeExtensionRequest.java b/server/src/main/java/org/opensearch/discovery/InitializeExtensionRequest.java
new file mode 100644
index 0000000000000..33cdad3045780
--- /dev/null
+++ b/server/src/main/java/org/opensearch/discovery/InitializeExtensionRequest.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.discovery;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * InitializeExtensionRequest to intialize plugin
+ *
+ * @opensearch.internal
+ */
+public class InitializeExtensionRequest extends TransportRequest {
+    private final DiscoveryNode sourceNode;
+    private final DiscoveryExtensionNode extension;
+
+    public InitializeExtensionRequest(DiscoveryNode sourceNode, DiscoveryExtensionNode extension) {
+        this.sourceNode = sourceNode;
+        this.extension = extension;
+    }
+
+    public InitializeExtensionRequest(StreamInput in) throws IOException {
+        super(in);
+        sourceNode = new DiscoveryNode(in);
+        extension = new DiscoveryExtensionNode(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        sourceNode.writeTo(out);
+        extension.writeTo(out);
+    }
+
+    public DiscoveryNode getSourceNode() {
+        return sourceNode;
+    }
+
+    public DiscoveryExtensionNode getExtension() {
+        return extension;
+    }
+
+    @Override
+    public String toString() {
+        return "InitializeExtensionsRequest{" + "sourceNode=" + sourceNode + ", extension=" + extension + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        InitializeExtensionRequest that = (InitializeExtensionRequest) o;
+        return Objects.equals(sourceNode, that.sourceNode) && Objects.equals(extension, that.extension);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(sourceNode, extension);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/discovery/InitializeExtensionResponse.java b/server/src/main/java/org/opensearch/discovery/InitializeExtensionResponse.java
new file mode 100644
index 0000000000000..0c6be72d0fe86
--- /dev/null
+++ b/server/src/main/java/org/opensearch/discovery/InitializeExtensionResponse.java
@@ -0,0 +1,102 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.discovery;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * PluginResponse to intialize plugin
+ *
+ * @opensearch.internal
+ */
+public class InitializeExtensionResponse extends TransportResponse {
+    private String name;
+    private List<String> implementedInterfaces;
+
+    public InitializeExtensionResponse(String name, List<String> implementedInterfaces) {
+        this.name = name;
+        this.implementedInterfaces = implementedInterfaces;
+    }
+
+    public InitializeExtensionResponse(StreamInput in) throws IOException {
+        name = in.readString();
+        this.implementedInterfaces = Arrays.asList(in.readStringArray());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(name);
+        out.writeStringArray(implementedInterfaces.toArray(new String[0]));
+    }
+
+    /**
+     * @return the node that is currently leading, according to the responding node.
+     */
+
+    public String getName() {
+        return this.name;
+    }
+
+    /**
+     * @return interfaces implemented by an extension
+     */
+
+    public List<String> getImplementedInterfaces() {
+        return implementedInterfaces;
+    }
+
+    @Override
+    public String toString() {
+        return "InitializeExtensionResponse{" + "name = " + name + " , " + "implementedInterfaces = " + implementedInterfaces + "}";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        InitializeExtensionResponse that = (InitializeExtensionResponse) o;
+        return Objects.equals(name, that.name) && Objects.equals(implementedInterfaces, that.implementedInterfaces);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, implementedInterfaces);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/discovery/MasterNotDiscoveredException.java b/server/src/main/java/org/opensearch/discovery/MasterNotDiscoveredException.java
index 337a6cf309dec..481b24f9a7288 100644
--- a/server/src/main/java/org/opensearch/discovery/MasterNotDiscoveredException.java
+++ b/server/src/main/java/org/opensearch/discovery/MasterNotDiscoveredException.java
@@ -6,42 +6,23 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.discovery;
 
-import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
-public class MasterNotDiscoveredException extends OpenSearchException {
+/**
+ * Exception when the cluster-manager is not discovered
+ *
+ * @opensearch.internal
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link ClusterManagerNotDiscoveredException}
+ */
+@Deprecated
+public class MasterNotDiscoveredException extends ClusterManagerNotDiscoveredException {
 
     public MasterNotDiscoveredException() {
-        super("");
+        super();
     }
 
     public MasterNotDiscoveredException(Throwable cause) {
@@ -52,11 +33,6 @@ public MasterNotDiscoveredException(String message) {
         super(message);
     }
 
-    @Override
-    public RestStatus status() {
-        return RestStatus.SERVICE_UNAVAILABLE;
-    }
-
     public MasterNotDiscoveredException(StreamInput in) throws IOException {
         super(in);
     }
diff --git a/server/src/main/java/org/opensearch/discovery/PeerFinder.java b/server/src/main/java/org/opensearch/discovery/PeerFinder.java
index 37f07c5d56a9a..1d997c8cbabe8 100644
--- a/server/src/main/java/org/opensearch/discovery/PeerFinder.java
+++ b/server/src/main/java/org/opensearch/discovery/PeerFinder.java
@@ -32,22 +32,21 @@
 
 package org.opensearch.discovery;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.PeersResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequestOptions;
@@ -65,6 +64,11 @@
 
 import static java.util.Collections.emptyList;
 
+/**
+ * finds peers
+ *
+ * @opensearch.internal
+ */
 public abstract class PeerFinder {
 
     private static final Logger logger = LogManager.getLogger(PeerFinder.class);
@@ -79,6 +83,14 @@ public abstract class PeerFinder {
         Setting.Property.NodeScope
     );
 
+    // the time between attempts to find all peers when node is in decommissioned state, default set to 2 minutes
+    public static final Setting<TimeValue> DISCOVERY_FIND_PEERS_INTERVAL_DURING_DECOMMISSION_SETTING = Setting.timeSetting(
+        "discovery.find_peers_interval_during_decommission",
+        TimeValue.timeValueSeconds(120L),
+        TimeValue.timeValueMillis(1000),
+        Setting.Property.NodeScope
+    );
+
     public static final Setting<TimeValue> DISCOVERY_REQUEST_PEERS_TIMEOUT_SETTING = Setting.timeSetting(
         "discovery.request_peers_timeout",
         TimeValue.timeValueMillis(3000),
@@ -86,7 +98,8 @@ public abstract class PeerFinder {
         Setting.Property.NodeScope
     );
 
-    private final TimeValue findPeersInterval;
+    private final Settings settings;
+    private TimeValue findPeersInterval;
     private final TimeValue requestPeersTimeout;
 
     private final Object mutex = new Object();
@@ -107,6 +120,7 @@ public PeerFinder(
         TransportAddressConnector transportAddressConnector,
         ConfiguredHostsResolver configuredHostsResolver
     ) {
+        this.settings = settings;
         findPeersInterval = DISCOVERY_FIND_PEERS_INTERVAL_SETTING.get(settings);
         requestPeersTimeout = DISCOVERY_REQUEST_PEERS_TIMEOUT_SETTING.get(settings);
         this.transportService = transportService;
@@ -123,6 +137,23 @@ public PeerFinder(
         );
     }
 
+    public synchronized void onNodeCommissionStatusChange(boolean localNodeCommissioned) {
+        findPeersInterval = localNodeCommissioned
+            ? DISCOVERY_FIND_PEERS_INTERVAL_SETTING.get(settings)
+            : DISCOVERY_FIND_PEERS_INTERVAL_DURING_DECOMMISSION_SETTING.get(settings);
+        logger.info(
+            "setting findPeersInterval to [{}] as node commission status = [{}] for local node [{}]",
+            findPeersInterval,
+            localNodeCommissioned,
+            transportService.getLocalNode()
+        );
+    }
+
+    // package private for tests
+    TimeValue getFindPeersInterval() {
+        return findPeersInterval;
+    }
+
     public void activate(final DiscoveryNodes lastAcceptedNodes) {
         logger.trace("activating with {}", lastAcceptedNodes);
 
@@ -169,7 +200,7 @@ PeersResponse handlePeersRequest(PeersRequest peersRequest) {
             final List<DiscoveryNode> knownPeers;
             if (active) {
                 assert leader.isPresent() == false : leader;
-                if (peersRequest.getSourceNode().isMasterNode()) {
+                if (peersRequest.getSourceNode().isClusterManagerNode()) {
                     startProbe(peersRequest.getSourceNode().getAddress());
                 }
                 peersRequest.getKnownPeers().stream().map(DiscoveryNode::getAddress).forEach(this::startProbe);
@@ -208,7 +239,7 @@ private DiscoveryNode getLocalNode() {
      * Invoked on receipt of a PeersResponse from a node that believes it's an active leader, which this node should therefore try and join.
      * Note that invocations of this method are not synchronised. By the time it is called we may have been deactivated.
      */
-    protected abstract void onActiveMasterFound(DiscoveryNode masterNode, long term);
+    protected abstract void onActiveClusterManagerFound(DiscoveryNode clusterManagerNode, long term);
 
     /**
      * Invoked when the set of found peers changes. Note that invocations of this method are not fully synchronised, so we only guarantee
@@ -223,13 +254,23 @@ public List<TransportAddress> getLastResolvedAddresses() {
         return lastResolvedAddresses;
     }
 
+    /**
+     * Transport address connector interface.
+     *
+     * @opensearch.internal
+     */
     public interface TransportAddressConnector {
         /**
-         * Identify the node at the given address and, if it is a master node and not the local node then establish a full connection to it.
+         * Identify the node at the given address and, if it is a cluster-manager node and not the local node then establish a full connection to it.
          */
         void connectToRemoteMasterNode(TransportAddress transportAddress, ActionListener<DiscoveryNode> listener);
     }
 
+    /**
+     * Resolves the configured unicast host.
+     *
+     * @opensearch.internal
+     */
     public interface ConfiguredHostsResolver {
         /**
          * Attempt to resolve the configured unicast hosts list to a list of transport addresses.
@@ -275,9 +316,9 @@ private boolean handleWakeUp() {
             return peersRemoved;
         }
 
-        logger.trace("probing master nodes from cluster state: {}", lastAcceptedNodes);
-        for (ObjectCursor<DiscoveryNode> discoveryNodeObjectCursor : lastAcceptedNodes.getMasterNodes().values()) {
-            startProbe(discoveryNodeObjectCursor.value.getAddress());
+        logger.trace("probing cluster-manager nodes from cluster state: {}", lastAcceptedNodes);
+        for (final DiscoveryNode discoveryNodeObjectCursor : lastAcceptedNodes.getClusterManagerNodes().values()) {
+            startProbe(discoveryNodeObjectCursor.getAddress());
         }
 
         configuredHostsResolver.resolveConfiguredHosts(providedAddresses -> {
@@ -381,7 +422,7 @@ void establishConnection() {
             transportAddressConnector.connectToRemoteMasterNode(transportAddress, new ActionListener<DiscoveryNode>() {
                 @Override
                 public void onResponse(DiscoveryNode remoteNode) {
-                    assert remoteNode.isMasterNode() : remoteNode + " is not master-eligible";
+                    assert remoteNode.isClusterManagerNode() : remoteNode + " is not cluster-manager-eligible";
                     assert remoteNode.equals(getLocalNode()) == false : remoteNode + " is the local node";
                     synchronized (mutex) {
                         if (active == false) {
@@ -442,14 +483,14 @@ public void handleResponse(PeersResponse response) {
 
                         peersRequestInFlight = false;
 
-                        response.getMasterNode().map(DiscoveryNode::getAddress).ifPresent(PeerFinder.this::startProbe);
+                        response.getClusterManagerNode().map(DiscoveryNode::getAddress).ifPresent(PeerFinder.this::startProbe);
                         response.getKnownPeers().stream().map(DiscoveryNode::getAddress).forEach(PeerFinder.this::startProbe);
                     }
 
-                    if (response.getMasterNode().equals(Optional.of(discoveryNode))) {
+                    if (response.getClusterManagerNode().equals(Optional.of(discoveryNode))) {
                         // Must not hold lock here to avoid deadlock
                         assert holdsLock() == false : "PeerFinder mutex is held in error";
-                        onActiveMasterFound(discoveryNode, response.getTerm());
+                        onActiveClusterManagerFound(discoveryNode, response.getTerm());
                     }
                 }
 
diff --git a/server/src/main/java/org/opensearch/discovery/PeersRequest.java b/server/src/main/java/org/opensearch/discovery/PeersRequest.java
index 6a96ee3450050..8a07571470804 100644
--- a/server/src/main/java/org/opensearch/discovery/PeersRequest.java
+++ b/server/src/main/java/org/opensearch/discovery/PeersRequest.java
@@ -33,14 +33,19 @@
 package org.opensearch.discovery;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Objects;
 
+/**
+ * Request sent to a peer node
+ *
+ * @opensearch.internal
+ */
 public class PeersRequest extends TransportRequest {
     private final DiscoveryNode sourceNode;
     private final List<DiscoveryNode> knownPeers;
diff --git a/server/src/main/java/org/opensearch/discovery/SeedHostsProvider.java b/server/src/main/java/org/opensearch/discovery/SeedHostsProvider.java
index ddea57db44476..89dfd9310e895 100644
--- a/server/src/main/java/org/opensearch/discovery/SeedHostsProvider.java
+++ b/server/src/main/java/org/opensearch/discovery/SeedHostsProvider.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.discovery;
 
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.util.List;
 
 /**
  * A pluggable provider of the list of seed hosts to use for discovery.
+ *
+ * @opensearch.internal
  */
 public interface SeedHostsProvider {
 
     /**
-     * Returns a list of seed hosts to use for discovery. Called repeatedly while discovery is active (i.e. while there is no master)
+     * Returns a list of seed hosts to use for discovery. Called repeatedly while discovery is active (i.e. while there is no cluster-manager)
      * so that this list may be dynamic.
      */
     List<TransportAddress> getSeedAddresses(HostsResolver hostsResolver);
diff --git a/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java b/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
index 0c002a2f29a5e..559a37d6e776b 100644
--- a/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
+++ b/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
@@ -34,15 +34,15 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.PeerFinder.ConfiguredHostsResolver;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -65,6 +65,11 @@
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
+/**
+ * Resolves seed hosts listed in the config
+ *
+ * @opensearch.internal
+ */
 public class SeedHostsResolver extends AbstractLifecycleComponent implements ConfiguredHostsResolver {
     public static final Setting<Integer> LEGACY_DISCOVERY_ZEN_PING_UNICAST_CONCURRENT_CONNECTS_SETTING = Setting.intSetting(
         "discovery.zen.ping.unicast.concurrent_connects",
diff --git a/server/src/main/java/org/opensearch/discovery/SettingsBasedSeedHostsProvider.java b/server/src/main/java/org/opensearch/discovery/SettingsBasedSeedHostsProvider.java
index 87fd49bde6aad..9785d5b21078e 100644
--- a/server/src/main/java/org/opensearch/discovery/SettingsBasedSeedHostsProvider.java
+++ b/server/src/main/java/org/opensearch/discovery/SettingsBasedSeedHostsProvider.java
@@ -37,7 +37,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.transport.TransportService;
 
 import java.util.List;
@@ -52,6 +52,8 @@
  *
  * An example setting might look as follows:
  * [67.81.244.10, 67.81.244.11:9305, 67.81.244.15:9400]
+ *
+ * @opensearch.internal
  */
 public class SettingsBasedSeedHostsProvider implements SeedHostsProvider {
 
diff --git a/server/src/main/java/org/opensearch/discovery/package-info.java b/server/src/main/java/org/opensearch/discovery/package-info.java
new file mode 100644
index 0000000000000..052a7d3027f07
--- /dev/null
+++ b/server/src/main/java/org/opensearch/discovery/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Node Discovery Module Foundation Classes. */
+package org.opensearch.discovery;
diff --git a/server/src/main/java/org/opensearch/env/Environment.java b/server/src/main/java/org/opensearch/env/Environment.java
index 88f324f4dbea9..0ffccaf1a7b3c 100644
--- a/server/src/main/java/org/opensearch/env/Environment.java
+++ b/server/src/main/java/org/opensearch/env/Environment.java
@@ -33,6 +33,7 @@
 package org.opensearch.env;
 
 import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
@@ -55,7 +56,10 @@
 
 /**
  * The environment of where things exists.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 @SuppressForbidden(reason = "configures paths for the system")
 // TODO: move PathUtils to be package-private here instead of
 // public+forbidden api!
@@ -91,6 +95,8 @@ public class Environment {
 
     private final Path pluginsFile;
 
+    private final Path extensionsDir;
+
     private final Path modulesFile;
 
     private final Path sharedDataFile;
@@ -135,6 +141,7 @@ public Environment(final Settings settings, final Path configPath, final boolean
         tmpFile = Objects.requireNonNull(tmpPath);
 
         pluginsFile = homeFile.resolve("plugins");
+        extensionsDir = homeFile.resolve("extensions");
 
         List<String> dataPaths = PATH_DATA_SETTING.get(settings);
         if (nodeLocalStorage) {
diff --git a/server/src/main/java/org/opensearch/env/EnvironmentSettingsResponse.java b/server/src/main/java/org/opensearch/env/EnvironmentSettingsResponse.java
new file mode 100644
index 0000000000000..eb115ee927d68
--- /dev/null
+++ b/server/src/main/java/org/opensearch/env/EnvironmentSettingsResponse.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.env;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Environment Settings Response for Extensibility
+ *
+ * @opensearch.internal
+ */
+public class EnvironmentSettingsResponse extends TransportResponse {
+    private final Settings environmentSettings;
+
+    public EnvironmentSettingsResponse(Settings environmentSettings) {
+        this.environmentSettings = environmentSettings;
+    }
+
+    public EnvironmentSettingsResponse(StreamInput in) throws IOException {
+        this.environmentSettings = Settings.readSettingsFromStream(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        Settings.writeSettingsToStream(this.environmentSettings, out);
+    }
+
+    public Settings getEnvironmentSettings() {
+        return environmentSettings;
+    }
+
+    @Override
+    public String toString() {
+        return "EnvironmentSettingsResponse{environmentSettings=" + environmentSettings.toString() + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        EnvironmentSettingsResponse that = (EnvironmentSettingsResponse) o;
+        return Objects.equals(environmentSettings, that.environmentSettings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(environmentSettings);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/env/NodeEnvironment.java b/server/src/main/java/org/opensearch/env/NodeEnvironment.java
index 555ca990b736d..89365f5e40434 100644
--- a/server/src/main/java/org/opensearch/env/NodeEnvironment.java
+++ b/server/src/main/java/org/opensearch/env/NodeEnvironment.java
@@ -53,21 +53,22 @@
 import org.opensearch.common.Randomness;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.gateway.MetadataStateFormat;
 import org.opensearch.gateway.PersistedClusterStateService;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.FsDirectoryFactory;
 import org.opensearch.monitor.fs.FsInfo;
@@ -107,8 +108,17 @@
 
 /**
  * A component that holds all data paths for a single node.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class NodeEnvironment implements Closeable {
+    /**
+     * A node path.
+     *
+     * @opensearch.api
+     */
+    @PublicApi(since = "1.0.0")
     public static class NodePath {
         /* ${data.paths}/nodes/{node.id} */
         public final Path path;
@@ -116,14 +126,20 @@ public static class NodePath {
         public final Path indicesPath;
         /** Cached FileStore from path */
         public final FileStore fileStore;
-
+        public final Path fileCachePath;
+        /*
+          Cache reserved size can default to a different value depending on configuration
+        */
+        public ByteSizeValue fileCacheReservedSize;
         public final int majorDeviceNumber;
         public final int minorDeviceNumber;
 
         public NodePath(Path path) throws IOException {
             this.path = path;
             this.indicesPath = path.resolve(INDICES_FOLDER);
+            this.fileCachePath = path.resolve(CACHE_FOLDER);
             this.fileStore = Environment.getFileStore(path);
+            this.fileCacheReservedSize = ByteSizeValue.ZERO;
             if (fileStore.supportsFileAttributeView("lucene")) {
                 this.majorDeviceNumber = (int) fileStore.getAttribute("lucene:major_device_number");
                 this.minorDeviceNumber = (int) fileStore.getAttribute("lucene:minor_device_number");
@@ -173,6 +189,7 @@ public String toString() {
 
     private final Logger logger = LogManager.getLogger(NodeEnvironment.class);
     private final NodePath[] nodePaths;
+    private final NodePath fileCacheNodePath;
     private final Path sharedDataPath;
     private final Lock[] locks;
 
@@ -210,8 +227,14 @@ public String toString() {
 
     public static final String NODES_FOLDER = "nodes";
     public static final String INDICES_FOLDER = "indices";
+    public static final String CACHE_FOLDER = "cache";
     public static final String NODE_LOCK_FILENAME = "node.lock";
 
+    /**
+     * The node lock.
+     *
+     * @opensearch.internal
+     */
     public static class NodeLock implements Releasable {
 
         private final int nodeId;
@@ -279,6 +302,7 @@ public void close() {
     public NodeEnvironment(Settings settings, Environment environment) throws IOException {
         if (!DiscoveryNode.nodeRequiresLocalStorage(settings)) {
             nodePaths = null;
+            fileCacheNodePath = null;
             sharedDataPath = null;
             locks = null;
             nodeLockId = -1;
@@ -330,6 +354,8 @@ public NodeEnvironment(Settings settings, Environment environment) throws IOExce
             }
             this.locks = nodeLock.locks;
             this.nodePaths = nodeLock.nodePaths;
+            this.fileCacheNodePath = nodePaths[0];
+
             this.nodeLockId = nodeLock.nodeId;
 
             if (logger.isDebugEnabled()) {
@@ -342,18 +368,22 @@ public NodeEnvironment(Settings settings, Environment environment) throws IOExce
             applySegmentInfosTrace(settings);
             assertCanWrite();
 
-            if (DiscoveryNode.isMasterNode(settings) || DiscoveryNode.isDataNode(settings)) {
+            if (DiscoveryNode.isClusterManagerNode(settings) || DiscoveryNode.isDataNode(settings)) {
                 ensureAtomicMoveSupported(nodePaths);
             }
 
             if (DiscoveryNode.isDataNode(settings) == false) {
-                if (DiscoveryNode.isMasterNode(settings) == false) {
+                if (DiscoveryNode.isClusterManagerNode(settings) == false) {
                     ensureNoIndexMetadata(nodePaths);
                 }
 
                 ensureNoShardData(nodePaths);
             }
 
+            if (DiscoveryNode.isSearchNode(settings) == false) {
+                ensureNoFileCacheData(fileCacheNodePath);
+            }
+
             this.nodeMetadata = loadNodeMetadata(settings, logger, nodePaths);
             success = true;
         } finally {
@@ -876,6 +906,17 @@ public NodePath[] nodePaths() {
         return nodePaths;
     }
 
+    /**
+     * Returns the {@link NodePath} used for file caching.
+     */
+    public NodePath fileCacheNodePath() {
+        assertEnvIsLocked();
+        if (nodePaths == null || locks == null) {
+            throw new IllegalStateException("node is not configured to store local location");
+        }
+        return fileCacheNodePath;
+    }
+
     public int getNodeLockId() {
         assertEnvIsLocked();
         if (nodePaths == null || locks == null) {
@@ -1131,6 +1172,22 @@ private void ensureNoShardData(final NodePath[] nodePaths) throws IOException {
         }
     }
 
+    /**
+     * Throws an exception if cache exists on a non-search node.
+     */
+    private void ensureNoFileCacheData(final NodePath fileCacheNodePath) throws IOException {
+        List<Path> cacheDataPaths = collectFileCacheDataPath(fileCacheNodePath);
+        if (cacheDataPaths.isEmpty() == false) {
+            final String message = String.format(
+                Locale.ROOT,
+                "node does not have the %s role but has data within node search cache: %s. Use 'opensearch-node repurpose' tool to clean up",
+                DiscoveryNodeRole.SEARCH_ROLE.roleName(),
+                cacheDataPaths
+            );
+            throw new IllegalStateException(message);
+        }
+    }
+
     private void ensureNoIndexMetadata(final NodePath[] nodePaths) throws IOException {
         List<Path> indexMetadataPaths = collectIndexMetadataPaths(nodePaths);
         if (indexMetadataPaths.isEmpty() == false) {
@@ -1188,6 +1245,29 @@ private static boolean isIndexMetadataPath(Path path) {
         return Files.isDirectory(path) && path.getFileName().toString().equals(MetadataStateFormat.STATE_DIR_NAME);
     }
 
+    /**
+     * Collect the path containing cache data in the indicated cache node path.
+     * The returned paths will point to the shard data folder.
+     */
+    public static List<Path> collectFileCacheDataPath(NodePath fileCacheNodePath) throws IOException {
+        // Structure is: <file cache path>/<index uuid>/<shard id>/...
+        List<Path> indexSubPaths = new ArrayList<>();
+        Path fileCachePath = fileCacheNodePath.fileCachePath;
+        if (Files.isDirectory(fileCachePath)) {
+            try (DirectoryStream<Path> indexStream = Files.newDirectoryStream(fileCachePath)) {
+                for (Path indexPath : indexStream) {
+                    if (Files.isDirectory(indexPath)) {
+                        try (Stream<Path> shardStream = Files.list(indexPath)) {
+                            shardStream.filter(NodeEnvironment::isShardPath).map(Path::toAbsolutePath).forEach(indexSubPaths::add);
+                        }
+                    }
+                }
+            }
+        }
+
+        return indexSubPaths;
+    }
+
     /**
      * Resolve the custom path for a index's shard.
      */
@@ -1216,6 +1296,16 @@ private static Path resolveIndexCustomLocation(String customDataPath, String ind
         return resolveBaseCustomLocation(customDataPath, sharedDataPath, nodeLockId).resolve(indexUUID);
     }
 
+    /**
+     * Resolve the file cache path for remote shards.
+     *
+     * @param fileCachePath the file cache path
+     * @param shardId shard to resolve the path to
+     */
+    public Path resolveFileCacheLocation(final Path fileCachePath, final ShardId shardId) {
+        return fileCachePath.resolve(shardId.getIndex().getUUID()).resolve(Integer.toString(shardId.id()));
+    }
+
     /**
      * Resolve the custom path for a index's shard.
      * Uses the {@code IndexMetadata.SETTING_DATA_PATH} setting to determine
diff --git a/server/src/main/java/org/opensearch/env/NodeMetadata.java b/server/src/main/java/org/opensearch/env/NodeMetadata.java
index cb6257002b62b..70fd92ff35652 100644
--- a/server/src/main/java/org/opensearch/env/NodeMetadata.java
+++ b/server/src/main/java/org/opensearch/env/NodeMetadata.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.MetadataStateFormat;
 
 import java.io.IOException;
@@ -48,6 +48,8 @@
 /**
  * Metadata associated with this node: its persistent node ID and its version.
  * The metadata is persisted in the data folder of this node and is reused across restarts.
+ *
+ * @opensearch.internal
  */
 public final class NodeMetadata {
 
diff --git a/server/src/main/java/org/opensearch/env/NodeRepurposeCommand.java b/server/src/main/java/org/opensearch/env/NodeRepurposeCommand.java
index d14b7df8b747a..3a8996afed34e 100644
--- a/server/src/main/java/org/opensearch/env/NodeRepurposeCommand.java
+++ b/server/src/main/java/org/opensearch/env/NodeRepurposeCommand.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.env;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import joptsimple.OptionParser;
 import joptsimple.OptionSet;
 import org.opensearch.OpenSearchException;
@@ -42,13 +41,14 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.gateway.MetadataStateFormat;
 import org.opensearch.gateway.PersistedClusterStateService;
 
 import java.io.IOException;
 import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
@@ -57,18 +57,26 @@
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
+import static org.opensearch.env.NodeEnvironment.CACHE_FOLDER;
 import static org.opensearch.env.NodeEnvironment.INDICES_FOLDER;
 
+/**
+ * Command to repurpose a node
+ *
+ * @opensearch.internal
+ */
 public class NodeRepurposeCommand extends OpenSearchNodeCommand {
 
     static final String ABORTED_BY_USER_MSG = OpenSearchNodeCommand.ABORTED_BY_USER_MSG;
     static final String FAILED_TO_OBTAIN_NODE_LOCK_MSG = OpenSearchNodeCommand.FAILED_TO_OBTAIN_NODE_LOCK_MSG;
-    static final String NO_CLEANUP = "Node has node.data=true -> no clean up necessary";
+    static final String NO_CLEANUP = "Node has node.data=true and node.search=true -> no clean up necessary";
     static final String NO_DATA_TO_CLEAN_UP_FOUND = "No data to clean-up found";
     static final String NO_SHARD_DATA_TO_CLEAN_UP_FOUND = "No shard data to clean-up found";
+    static final String NO_FILE_CACHE_DATA_TO_CLEAN_UP_FOUND = "No file cache to clean-up found";
+    private static final int FILE_CACHE_NODE_PATH_LOCATION = 0;
 
     public NodeRepurposeCommand() {
-        super("Repurpose this node to another master/data role, cleaning up any excess persisted data");
+        super("Repurpose this node to another cluster-manager/data/search role, cleaning up any excess persisted data");
     }
 
     void testExecute(Terminal terminal, OptionSet options, Environment env) throws Exception {
@@ -78,7 +86,7 @@ void testExecute(Terminal terminal, OptionSet options, Environment env) throws E
     @Override
     protected boolean validateBeforeLock(Terminal terminal, Environment env) {
         Settings settings = env.settings();
-        if (DiscoveryNode.isDataNode(settings)) {
+        if (DiscoveryNode.isDataNode(settings) && DiscoveryNode.isSearchNode(settings)) {
             terminal.println(Terminal.Verbosity.NORMAL, NO_CLEANUP);
             return false;
         }
@@ -89,85 +97,186 @@ protected boolean validateBeforeLock(Terminal terminal, Environment env) {
     @Override
     protected void processNodePaths(Terminal terminal, Path[] dataPaths, int nodeLockId, OptionSet options, Environment env)
         throws IOException {
-        assert DiscoveryNode.isDataNode(env.settings()) == false;
+        assert DiscoveryNode.isDataNode(env.settings()) == false || DiscoveryNode.isSearchNode(env.settings()) == false;
+
+        boolean repurposeData = DiscoveryNode.isDataNode(env.settings()) == false;
+        boolean repurposeSearch = DiscoveryNode.isSearchNode(env.settings()) == false;
 
-        if (DiscoveryNode.isMasterNode(env.settings()) == false) {
-            processNoMasterNoDataNode(terminal, dataPaths, env);
+        if (DiscoveryNode.isClusterManagerNode(env.settings()) == false) {
+            processNoClusterManagerRepurposeNode(terminal, dataPaths, env, repurposeData, repurposeSearch);
         } else {
-            processMasterNoDataNode(terminal, dataPaths, env);
+            processClusterManagerRepurposeNode(terminal, dataPaths, env, repurposeData, repurposeSearch);
         }
     }
 
-    private void processNoMasterNoDataNode(Terminal terminal, Path[] dataPaths, Environment env) throws IOException {
+    private void processNoClusterManagerRepurposeNode(
+        Terminal terminal,
+        Path[] dataPaths,
+        Environment env,
+        boolean repurposeData,
+        boolean repurposeSearch
+    ) throws IOException {
         NodeEnvironment.NodePath[] nodePaths = toNodePaths(dataPaths);
+        NodeEnvironment.NodePath fileCacheNodePath = toNodePaths(dataPaths)[FILE_CACHE_NODE_PATH_LOCATION];
+        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
+        final Metadata metadata = loadClusterState(terminal, env, persistedClusterStateService).metadata();
 
-        terminal.println(Terminal.Verbosity.VERBOSE, "Collecting shard data paths");
-        List<Path> shardDataPaths = NodeEnvironment.collectShardDataPaths(nodePaths);
+        Set<Path> indexPaths = Set.of();
+        List<Path> shardDataPaths = List.of();
+        Set<Path> fileCachePaths = Set.of();
+        List<Path> fileCacheDataPaths = List.of();
 
         terminal.println(Terminal.Verbosity.VERBOSE, "Collecting index metadata paths");
         List<Path> indexMetadataPaths = NodeEnvironment.collectIndexMetadataPaths(nodePaths);
 
-        Set<Path> indexPaths = uniqueParentPaths(shardDataPaths, indexMetadataPaths);
+        if (repurposeData) {
+            terminal.println(Terminal.Verbosity.VERBOSE, "Collecting shard data paths");
+            shardDataPaths = NodeEnvironment.collectShardDataPaths(nodePaths);
+            indexPaths = uniqueParentPaths(shardDataPaths, indexMetadataPaths);
+        }
 
-        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
+        if (repurposeSearch) {
+            terminal.println(Terminal.Verbosity.VERBOSE, "Collecting file cache data paths");
+            fileCacheDataPaths = NodeEnvironment.collectFileCacheDataPath(fileCacheNodePath);
+            fileCachePaths = uniqueParentPaths(fileCacheDataPaths, indexMetadataPaths);
+        }
 
-        final Metadata metadata = loadClusterState(terminal, env, persistedClusterStateService).metadata();
-        if (indexPaths.isEmpty() && metadata.indices().isEmpty()) {
+        if (repurposeData && repurposeSearch && fileCacheDataPaths.isEmpty() && indexPaths.isEmpty() && metadata.indices().isEmpty()) {
+            terminal.println(Terminal.Verbosity.NORMAL, NO_DATA_TO_CLEAN_UP_FOUND);
+            return;
+        } else if (repurposeData && !repurposeSearch && indexPaths.isEmpty() && metadata.indices().isEmpty()) {
             terminal.println(Terminal.Verbosity.NORMAL, NO_DATA_TO_CLEAN_UP_FOUND);
             return;
+        } else if (!repurposeData && repurposeSearch && fileCacheDataPaths.isEmpty() && metadata.indices().isEmpty()) {
+            terminal.println(NO_FILE_CACHE_DATA_TO_CLEAN_UP_FOUND);
+            return;
         }
 
         final Set<String> indexUUIDs = Sets.union(
-            indexUUIDsFor(indexPaths),
-            StreamSupport.stream(metadata.indices().values().spliterator(), false)
-                .map(imd -> imd.value.getIndexUUID())
-                .collect(Collectors.toSet())
+            indexUUIDsFor(fileCachePaths),
+            Sets.union(
+                indexUUIDsFor(indexPaths),
+                StreamSupport.stream(metadata.indices().values().spliterator(), false)
+                    .map(imd -> imd.getIndexUUID())
+                    .collect(Collectors.toSet())
+            )
         );
 
-        outputVerboseInformation(terminal, indexPaths, indexUUIDs, metadata);
-
-        terminal.println(noMasterMessage(indexUUIDs.size(), shardDataPaths.size(), indexMetadataPaths.size()));
+        List<Path> cleanUpPaths = new ArrayList<>(shardDataPaths);
+        cleanUpPaths.addAll(fileCacheDataPaths);
+        outputVerboseInformation(terminal, cleanUpPaths, indexUUIDs, metadata);
+        terminal.println(noClusterManagerMessage(indexUUIDs.size(), cleanUpPaths.size(), indexMetadataPaths.size()));
         outputHowToSeeVerboseInformation(terminal);
 
-        terminal.println("Node is being re-purposed as no-master and no-data. Clean-up of index data will be performed.");
+        if (repurposeData && repurposeSearch) {
+            terminal.println(
+                "Node is being re-purposed as no-cluster-manager, no-data and no-search. Clean-up of index data and file cache will be performed."
+            );
+        } else if (repurposeData) {
+            terminal.println("Node is being re-purposed as no-cluster-manager and no-data. Clean-up of index data will be performed.");
+        } else if (repurposeSearch) {
+            terminal.println(
+                "Node is being re-purposed as no-cluster-manager and no-search. Clean-up of file cache and corresponding index metadata will be performed."
+            );
+        }
         confirm(terminal, "Do you want to proceed?");
 
-        removePaths(terminal, indexPaths); // clean-up shard dirs
         // clean-up all metadata dirs
         MetadataStateFormat.deleteMetaState(dataPaths);
-        IOUtils.rm(Stream.of(dataPaths).map(path -> path.resolve(INDICES_FOLDER)).toArray(Path[]::new));
+        if (repurposeData) {
+            removePaths(terminal, indexPaths); // clean-up shard dirs
+            IOUtils.rm(Stream.of(dataPaths).map(path -> path.resolve(INDICES_FOLDER)).toArray(Path[]::new));
+        }
 
-        terminal.println("Node successfully repurposed to no-master and no-data.");
+        if (repurposeSearch) {
+            removePaths(terminal, fileCachePaths); // clean-up file cache dirs
+            IOUtils.rm(dataPaths[FILE_CACHE_NODE_PATH_LOCATION].resolve(CACHE_FOLDER));
+        }
+
+        if (repurposeData && repurposeSearch) {
+            terminal.println("Node successfully repurposed to no-cluster-manager, no-data and no-search.");
+        } else if (repurposeData) {
+            terminal.println("Node successfully repurposed to no-cluster-manager and no-data.");
+        } else if (repurposeSearch) {
+            terminal.println("Node successfully repurposed to no-cluster-manager and no-search.");
+        }
     }
 
-    private void processMasterNoDataNode(Terminal terminal, Path[] dataPaths, Environment env) throws IOException {
+    private void processClusterManagerRepurposeNode(
+        Terminal terminal,
+        Path[] dataPaths,
+        Environment env,
+        boolean repurposeData,
+        boolean repurposeSearch
+    ) throws IOException {
         NodeEnvironment.NodePath[] nodePaths = toNodePaths(dataPaths);
+        NodeEnvironment.NodePath fileCacheNodePath = toNodePaths(dataPaths)[FILE_CACHE_NODE_PATH_LOCATION];
+        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
+        final Metadata metadata = loadClusterState(terminal, env, persistedClusterStateService).metadata();
 
-        terminal.println(Terminal.Verbosity.VERBOSE, "Collecting shard data paths");
-        List<Path> shardDataPaths = NodeEnvironment.collectShardDataPaths(nodePaths);
-        if (shardDataPaths.isEmpty()) {
-            terminal.println(NO_SHARD_DATA_TO_CLEAN_UP_FOUND);
-            return;
-        }
+        Set<Path> indexPaths = Set.of();
+        List<Path> shardDataPaths = List.of();
+        Set<Path> fileCachePaths = Set.of();
+        List<Path> fileCacheDataPaths = List.of();
 
-        final PersistedClusterStateService persistedClusterStateService = createPersistedClusterStateService(env.settings(), dataPaths);
+        if (repurposeData) {
+            terminal.println(Terminal.Verbosity.VERBOSE, "Collecting shard data paths");
+            shardDataPaths = NodeEnvironment.collectShardDataPaths(nodePaths);
+            indexPaths = uniqueParentPaths(shardDataPaths);
+        }
 
-        final Metadata metadata = loadClusterState(terminal, env, persistedClusterStateService).metadata();
+        if (repurposeSearch) {
+            terminal.println(Terminal.Verbosity.VERBOSE, "Collecting file cache data paths");
+            fileCacheDataPaths = NodeEnvironment.collectFileCacheDataPath(fileCacheNodePath);
+            fileCachePaths = uniqueParentPaths(fileCacheDataPaths);
+        }
 
-        final Set<Path> indexPaths = uniqueParentPaths(shardDataPaths);
-        final Set<String> indexUUIDs = indexUUIDsFor(indexPaths);
+        if (repurposeData && repurposeSearch && shardDataPaths.isEmpty() && fileCacheDataPaths.isEmpty()) {
+            terminal.println(NO_SHARD_DATA_TO_CLEAN_UP_FOUND);
+            return;
+        } else if (repurposeData && !repurposeSearch && shardDataPaths.isEmpty()) {
+            terminal.println(NO_SHARD_DATA_TO_CLEAN_UP_FOUND);
+            return;
+        } else if (!repurposeData && repurposeSearch && fileCacheDataPaths.isEmpty()) {
+            terminal.println(NO_FILE_CACHE_DATA_TO_CLEAN_UP_FOUND);
+            return;
+        }
 
-        outputVerboseInformation(terminal, shardDataPaths, indexUUIDs, metadata);
+        final Set<String> indexUUIDs = Sets.union(indexUUIDsFor(indexPaths), indexUUIDsFor(fileCachePaths));
 
-        terminal.println(shardMessage(shardDataPaths.size(), indexUUIDs.size()));
+        List<Path> cleanUpPaths = new ArrayList<>(shardDataPaths);
+        cleanUpPaths.addAll(fileCacheDataPaths);
+        outputVerboseInformation(terminal, cleanUpPaths, indexUUIDs, metadata);
+        terminal.println(shardMessage(cleanUpPaths.size(), indexUUIDs.size()));
         outputHowToSeeVerboseInformation(terminal);
 
-        terminal.println("Node is being re-purposed as master and no-data. Clean-up of shard data will be performed.");
+        if (repurposeData && repurposeSearch) {
+            terminal.println(
+                "Node is being re-purposed as cluster-manager, no-data and no-search. Clean-up of shard data and file cache data will be performed."
+            );
+        } else if (repurposeData) {
+            terminal.println("Node is being re-purposed as cluster-manager and no-data. Clean-up of shard data will be performed.");
+        } else if (repurposeSearch) {
+            terminal.println("Node is being re-purposed as cluster-manager and no-search. Clean-up of file cache data will be performed.");
+        }
+
         confirm(terminal, "Do you want to proceed?");
 
-        removePaths(terminal, shardDataPaths); // clean-up shard dirs
+        if (repurposeData) {
+            removePaths(terminal, shardDataPaths); // clean-up shard dirs
+        }
+
+        if (repurposeSearch) {
+            removePaths(terminal, fileCacheDataPaths); // clean-up file cache dirs
+        }
 
-        terminal.println("Node successfully repurposed to master and no-data.");
+        if (repurposeData && repurposeSearch) {
+            terminal.println("Node successfully repurposed to cluster-manager, no-data and no-search.");
+        } else if (repurposeData) {
+            terminal.println("Node successfully repurposed to cluster-manager and no-data.");
+        } else if (repurposeSearch) {
+            terminal.println("Node successfully repurposed to cluster-manager and no-search.");
+        }
     }
 
     private ClusterState loadClusterState(Terminal terminal, Environment env, PersistedClusterStateService psf) throws IOException {
@@ -192,9 +301,9 @@ private void outputHowToSeeVerboseInformation(Terminal terminal) {
 
     private String toIndexName(String uuid, Metadata metadata) {
         if (metadata != null) {
-            for (ObjectObjectCursor<String, IndexMetadata> indexMetadata : metadata.indices()) {
-                if (indexMetadata.value.getIndexUUID().equals(uuid)) {
-                    return indexMetadata.value.getIndex().getName();
+            for (final IndexMetadata indexMetadata : metadata.indices().values()) {
+                if (indexMetadata.getIndexUUID().equals(uuid)) {
+                    return indexMetadata.getIndex().getName();
                 }
             }
         }
@@ -205,12 +314,18 @@ private Set<String> indexUUIDsFor(Set<Path> indexPaths) {
         return indexPaths.stream().map(Path::getFileName).map(Path::toString).collect(Collectors.toSet());
     }
 
-    static String noMasterMessage(int indexes, int shards, int indexMetadata) {
-        return "Found " + indexes + " indices (" + shards + " shards and " + indexMetadata + " index meta data) to clean up";
+    static String noClusterManagerMessage(int indexes, int shards, int indexMetadata) {
+        return "Found "
+            + indexes
+            + " indices ("
+            + shards
+            + " shards/file cache folders and "
+            + indexMetadata
+            + " index meta data) to clean up";
     }
 
     static String shardMessage(int shards, int indices) {
-        return "Found " + shards + " shards in " + indices + " indices to clean up";
+        return "Found " + shards + " shards/file cache folders in " + indices + " indices to clean up";
     }
 
     private void removePaths(Terminal terminal, Collection<Path> paths) {
diff --git a/server/src/main/java/org/opensearch/env/OpenSearchFileStore.java b/server/src/main/java/org/opensearch/env/OpenSearchFileStore.java
index dce985f8320d4..834fb0e748915 100644
--- a/server/src/main/java/org/opensearch/env/OpenSearchFileStore.java
+++ b/server/src/main/java/org/opensearch/env/OpenSearchFileStore.java
@@ -49,6 +49,8 @@
  * additional features, such as SSD detection and better
  * filesystem information for the root filesystem.
  * @see Environment#getFileStore(Path)
+ *
+ * @opensearch.internal
  */
 class OpenSearchFileStore extends FileStore {
     /** Underlying filestore */
diff --git a/server/src/main/java/org/opensearch/env/OverrideNodeVersionCommand.java b/server/src/main/java/org/opensearch/env/OverrideNodeVersionCommand.java
index ec92d00a88a6e..d07ea1acd25fa 100644
--- a/server/src/main/java/org/opensearch/env/OverrideNodeVersionCommand.java
+++ b/server/src/main/java/org/opensearch/env/OverrideNodeVersionCommand.java
@@ -43,6 +43,11 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 
+/**
+ * Command to override a node version
+ *
+ * @opensearch.internal
+ */
 public class OverrideNodeVersionCommand extends OpenSearchNodeCommand {
     private static final String TOO_NEW_MESSAGE = DELIMITER
         + "\n"
diff --git a/server/src/main/java/org/opensearch/env/ShardLock.java b/server/src/main/java/org/opensearch/env/ShardLock.java
index 21278a41dc76f..76afc0ec0329a 100644
--- a/server/src/main/java/org/opensearch/env/ShardLock.java
+++ b/server/src/main/java/org/opensearch/env/ShardLock.java
@@ -32,7 +32,8 @@
 
 package org.opensearch.env;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.Closeable;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -43,7 +44,10 @@
  * before executing any write operations on the shards data directory.
  *
  * @see NodeEnvironment
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public abstract class ShardLock implements Closeable {
 
     private final ShardId shardId;
diff --git a/server/src/main/java/org/opensearch/env/ShardLockObtainFailedException.java b/server/src/main/java/org/opensearch/env/ShardLockObtainFailedException.java
index 0bcd4c4128dbe..ae77d942356b5 100644
--- a/server/src/main/java/org/opensearch/env/ShardLockObtainFailedException.java
+++ b/server/src/main/java/org/opensearch/env/ShardLockObtainFailedException.java
@@ -33,14 +33,18 @@
 package org.opensearch.env;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Exception used when the in-memory lock for a shard cannot be obtained
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class ShardLockObtainFailedException extends OpenSearchException {
 
     public ShardLockObtainFailedException(ShardId shardId, String message) {
diff --git a/server/src/main/java/org/opensearch/env/package-info.java b/server/src/main/java/org/opensearch/env/package-info.java
new file mode 100644
index 0000000000000..8675321616eaa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/env/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch Environment Foundation Classes. */
+package org.opensearch.env;
diff --git a/server/src/main/java/org/opensearch/extensions/AcknowledgedResponse.java b/server/src/main/java/org/opensearch/extensions/AcknowledgedResponse.java
new file mode 100644
index 0000000000000..076ab41a077c4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/AcknowledgedResponse.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Generic boolean response indicating the status of some previous request sent to the SDK
+ *
+ * @opensearch.internal
+ */
+public class AcknowledgedResponse extends TransportResponse {
+
+    private final boolean status;
+
+    /**
+     * @param status Boolean indicating the status of the parse request sent to the SDK
+     */
+    public AcknowledgedResponse(boolean status) {
+        this.status = status;
+    }
+
+    public AcknowledgedResponse(StreamInput in) throws IOException {
+        super(in);
+        this.status = in.readBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeBoolean(status);
+    }
+
+    @Override
+    public String toString() {
+        return "AcknowledgedResponse{" + "status=" + this.status + "}";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        AcknowledgedResponse that = (AcknowledgedResponse) o;
+        return Objects.equals(this.status, that.status);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(status);
+    }
+
+    /**
+     * Returns a boolean indicating the success of the request sent to the SDK
+     */
+    public boolean getStatus() {
+        return this.status;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequest.java b/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequest.java
new file mode 100644
index 0000000000000..24984a3800819
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequest.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.WriteableSetting;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Add Settings Update Consumer Request for Extensibility
+ *
+ * @opensearch.internal
+ */
+public class AddSettingsUpdateConsumerRequest extends TransportRequest {
+    private final DiscoveryExtensionNode extensionNode;
+    private final List<WriteableSetting> componentSettings;
+
+    public AddSettingsUpdateConsumerRequest(DiscoveryExtensionNode extensionNode, List<Setting<?>> componentSettings) {
+        this.extensionNode = extensionNode;
+        this.componentSettings = new ArrayList<>(componentSettings.size());
+        for (Setting<?> setting : componentSettings) {
+            this.componentSettings.add(new WriteableSetting(setting));
+        }
+    }
+
+    public AddSettingsUpdateConsumerRequest(StreamInput in) throws IOException {
+        super(in);
+
+        // Set extension node to send update settings request to
+        this.extensionNode = new DiscoveryExtensionNode(in);
+
+        // Read in component setting list
+        int componentSettingsCount = in.readVInt();
+        this.componentSettings = new ArrayList<>(componentSettingsCount);
+        for (int i = 0; i < componentSettingsCount; i++) {
+            this.componentSettings.add(new WriteableSetting(in));
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+
+        // Write extension node to stream output
+        this.extensionNode.writeTo(out);
+
+        // Write component setting list to stream output
+        out.writeVInt(this.componentSettings.size());
+        for (WriteableSetting componentSetting : this.componentSettings) {
+            componentSetting.writeTo(out);
+        }
+    }
+
+    public List<WriteableSetting> getComponentSettings() {
+        return new ArrayList<>(this.componentSettings);
+    }
+
+    public DiscoveryExtensionNode getExtensionNode() {
+        return this.extensionNode;
+    }
+
+    @Override
+    public String toString() {
+        return "AddSettingsUpdateConsumerRequest{extensionNode=" + this.extensionNode.toString() + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        AddSettingsUpdateConsumerRequest that = (AddSettingsUpdateConsumerRequest) obj;
+        return Objects.equals(extensionNode, that.extensionNode) && Objects.equals(componentSettings, that.componentSettings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(extensionNode, componentSettings);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequestHandler.java b/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequestHandler.java
new file mode 100644
index 0000000000000..190a207a70737
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/AddSettingsUpdateConsumerRequestHandler.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.WriteableSetting;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.transport.TransportService;
+
+import java.util.List;
+
+/**
+ * Handles requests to add setting update consumers
+ *
+ * @opensearch.internal
+ */
+public class AddSettingsUpdateConsumerRequestHandler {
+
+    private static final Logger logger = LogManager.getLogger(AddSettingsUpdateConsumerRequestHandler.class);
+
+    private final ClusterService clusterService;
+    private final TransportService transportService;
+    private final String updateSettingsRequestType;
+
+    /**
+     * Instantiates a new Add Settings Update Consumer Request Handler with the {@link ClusterService} and {@link TransportService}
+     *
+     * @param clusterService the cluster service used to extract cluster settings
+     * @param transportService the node's transport service
+     * @param updateSettingsRequestType the update settings request type
+     */
+    public AddSettingsUpdateConsumerRequestHandler(
+        ClusterService clusterService,
+        TransportService transportService,
+        String updateSettingsRequestType
+    ) {
+        this.clusterService = clusterService;
+        this.transportService = transportService;
+        this.updateSettingsRequestType = updateSettingsRequestType;
+    }
+
+    /**
+     * Handles a {@link AddSettingsUpdateConsumerRequest}.
+     *
+     * @param addSettingsUpdateConsumerRequest  The request to handle.
+     * @return  A {@link AcknowledgedResponse} indicating success.
+     * @throws Exception if the request is not handled properly.
+     */
+    TransportResponse handleAddSettingsUpdateConsumerRequest(AddSettingsUpdateConsumerRequest addSettingsUpdateConsumerRequest)
+        throws Exception {
+
+        boolean status = true;
+        List<WriteableSetting> extensionComponentSettings = addSettingsUpdateConsumerRequest.getComponentSettings();
+        DiscoveryExtensionNode extensionNode = addSettingsUpdateConsumerRequest.getExtensionNode();
+
+        try {
+            for (WriteableSetting extensionComponentSetting : extensionComponentSettings) {
+
+                // Extract setting and type from writeable setting
+                Setting<?> setting = extensionComponentSetting.getSetting();
+                WriteableSetting.SettingType settingType = extensionComponentSetting.getType();
+
+                // Register setting update consumer with callback method to extension
+                clusterService.getClusterSettings().addSettingsUpdateConsumer(setting, (data) -> {
+                    logger.debug("Sending extension request type: " + updateSettingsRequestType);
+                    UpdateSettingsResponseHandler updateSettingsResponseHandler = new UpdateSettingsResponseHandler();
+                    transportService.sendRequest(
+                        extensionNode,
+                        updateSettingsRequestType,
+                        new UpdateSettingsRequest(settingType, setting, data),
+                        updateSettingsResponseHandler
+                    );
+                });
+            }
+        } catch (IllegalArgumentException e) {
+            logger.error(e.toString());
+            status = false;
+        }
+
+        return new AcknowledgedResponse(status);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/DiscoveryExtensionNode.java b/server/src/main/java/org/opensearch/extensions/DiscoveryExtensionNode.java
new file mode 100644
index 0000000000000..a888f99ff11ed
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/DiscoveryExtensionNode.java
@@ -0,0 +1,121 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Discover extensions running independently or in a separate process
+ *
+ * @opensearch.internal
+ */
+public class DiscoveryExtensionNode extends DiscoveryNode implements Writeable, ToXContentFragment {
+
+    private Version minimumCompatibleVersion;
+    private List<ExtensionDependency> dependencies = Collections.emptyList();
+    private List<String> implementedInterfaces = Collections.emptyList();
+
+    public DiscoveryExtensionNode(
+        String name,
+        String id,
+        TransportAddress address,
+        Map<String, String> attributes,
+        Version version,
+        Version minimumCompatibleVersion,
+        List<ExtensionDependency> dependencies
+    ) {
+        super(name, id, address, attributes, DiscoveryNodeRole.BUILT_IN_ROLES, version);
+        this.minimumCompatibleVersion = minimumCompatibleVersion;
+        this.dependencies = dependencies;
+        validate();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeVersion(minimumCompatibleVersion);
+        out.writeVInt(dependencies.size());
+        for (ExtensionDependency dependency : dependencies) {
+            dependency.writeTo(out);
+        }
+    }
+
+    /**
+     * Construct DiscoveryExtensionNode from a stream.
+     *
+     * @param in the stream
+     * @throws IOException if an I/O exception occurred reading the plugin info from the stream
+     */
+    public DiscoveryExtensionNode(final StreamInput in) throws IOException {
+        super(in);
+        minimumCompatibleVersion = in.readVersion();
+        int size = in.readVInt();
+        dependencies = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            dependencies.add(new ExtensionDependency(in));
+        }
+    }
+
+    public List<ExtensionDependency> getDependencies() {
+        return dependencies;
+    }
+
+    public Version getMinimumCompatibleVersion() {
+        return minimumCompatibleVersion;
+    }
+
+    public List<String> getImplementedInterfaces() {
+        return implementedInterfaces;
+    }
+
+    public void setImplementedInterfaces(List<String> implementedInterfaces) {
+        this.implementedInterfaces = implementedInterfaces;
+    }
+
+    public boolean dependenciesContain(ExtensionDependency dependency) {
+        for (ExtensionDependency extensiondependency : this.dependencies) {
+            if (dependency.getUniqueId().equals(extensiondependency.getUniqueId())
+                && dependency.getVersion().equals(extensiondependency.getVersion())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void validate() {
+        if (!Version.CURRENT.onOrAfter(minimumCompatibleVersion)) {
+            throw new OpenSearchException(
+                "Extension minimumCompatibleVersion: "
+                    + minimumCompatibleVersion
+                    + " is greater than current OpenSearch version: "
+                    + Version.CURRENT
+            );
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionDependency.java b/server/src/main/java/org/opensearch/extensions/ExtensionDependency.java
new file mode 100644
index 0000000000000..99f6a063b437e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionDependency.java
@@ -0,0 +1,91 @@
+/*
+* Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.Version;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * This class handles the dependent extensions information
+ *
+ * @opensearch.internal
+ */
+public class ExtensionDependency implements Writeable {
+    private String uniqueId;
+    private Version version;
+    private static final String UNIQUE_ID = "uniqueId";
+    private static final String VERSION = "version";
+
+    public ExtensionDependency(String uniqueId, Version version) {
+        this.uniqueId = uniqueId;
+        this.version = version;
+    }
+
+    /**
+     * Jackson requires a no-arg constructor.
+     *
+     */
+    @SuppressWarnings("unused")
+    private ExtensionDependency() {}
+
+    /**
+    * Reads the extension dependency information
+    *
+    * @throws IOException if an I/O exception occurred reading the extension dependency information
+    */
+    public ExtensionDependency(StreamInput in) throws IOException {
+        uniqueId = in.readString();
+        version = in.readVersion();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(uniqueId);
+        out.writeVersion(version);
+    }
+
+    /**
+    * The uniqueId of the dependency extension
+    *
+    * @return the extension uniqueId
+    */
+    public String getUniqueId() {
+        return uniqueId;
+    }
+
+    /**
+    * The minimum version of the dependency extension
+    *
+    * @return the extension version
+    */
+    public Version getVersion() {
+        return version;
+    }
+
+    public String toString() {
+        return "ExtensionDependency:{uniqueId=" + uniqueId + ", version=" + version + "}";
+    }
+
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        ExtensionDependency that = (ExtensionDependency) obj;
+        return Objects.equals(uniqueId, that.uniqueId) && Objects.equals(version, that.version);
+    }
+
+    public int hashCode() {
+        return Objects.hash(uniqueId, version);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionDependencyResponse.java b/server/src/main/java/org/opensearch/extensions/ExtensionDependencyResponse.java
new file mode 100644
index 0000000000000..4706d1821ffa9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionDependencyResponse.java
@@ -0,0 +1,70 @@
+/*
+* Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * The response for getting the Extension Dependency.
+ *
+ * @opensearch.internal
+ */
+public class ExtensionDependencyResponse extends TransportResponse {
+    private List<DiscoveryExtensionNode> extensionDependencies;
+
+    public ExtensionDependencyResponse(List<DiscoveryExtensionNode> extensionDependencies) {
+        this.extensionDependencies = extensionDependencies;
+    }
+
+    public ExtensionDependencyResponse(StreamInput in) throws IOException {
+        int size = in.readVInt();
+        extensionDependencies = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            extensionDependencies.add(new DiscoveryExtensionNode(in));
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVInt(extensionDependencies.size());
+        for (DiscoveryExtensionNode dependency : extensionDependencies) {
+            dependency.writeTo(out);
+        }
+    }
+
+    public List<DiscoveryExtensionNode> getExtensionDependency() {
+        return extensionDependencies;
+    }
+
+    @Override
+    public String toString() {
+        return "ExtensionDependencyResponse{extensiondependency=" + extensionDependencies.toString() + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ExtensionDependencyResponse that = (ExtensionDependencyResponse) o;
+        return Objects.equals(extensionDependencies, that.extensionDependencies);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(extensionDependencies);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionReader.java b/server/src/main/java/org/opensearch/extensions/ExtensionReader.java
new file mode 100644
index 0000000000000..4556d6537ffdc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionReader.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+
+import java.net.UnknownHostException;
+
+/**
+ * Reference to a method that transports a parse request to an extension. By convention, this method takes
+ * a category class used to identify the reader defined within the JVM that the extension is running on.
+ * Additionally, this method takes in the extension's corresponding DiscoveryNode and a byte array (context) that the
+ * extension's reader will be applied to.
+ *
+ * By convention the extensions' reader is a constructor that takes StreamInput as an argument for most classes and a static method for things like enums.
+ * Classes will implement this via a constructor (or a static method in the case of enumerations), it's something that should
+ * look like:
+ * <pre><code>
+ * public MyClass(final StreamInput in) throws IOException {
+ * *     this.someValue = in.readVInt();
+ *     this.someMap = in.readMapOfLists(StreamInput::readString, StreamInput::readString);
+ * }
+ * </code></pre>
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface ExtensionReader {
+
+    /**
+     * Transports category class, and StreamInput (context), to the extension identified by the Discovery Node
+     *
+     * @param extensionNode Discovery Node identifying the Extension
+     * @param categoryClass Super class that the reader extends
+     * @param context Some context to transport
+     * @throws UnknownHostException if the extension node host IP address could not be determined
+     */
+    void parse(DiscoveryNode extensionNode, Class categoryClass, Object context) throws UnknownHostException;
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionRequest.java b/server/src/main/java/org/opensearch/extensions/ExtensionRequest.java
new file mode 100644
index 0000000000000..19424e5213151
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionRequest.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionIdentityProto;
+import org.opensearch.extensions.proto.ExtensionRequestProto;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * CLusterService Request for Extensibility
+ *
+ * @opensearch.internal
+ */
+public class ExtensionRequest extends TransportRequest {
+    private static final Logger logger = LogManager.getLogger(ExtensionRequest.class);
+    private final ExtensionRequestProto.ExtensionRequest request;
+
+    public ExtensionRequest(ExtensionRequestProto.RequestType requestType) {
+        this(requestType, null);
+    }
+
+    public ExtensionRequest(ExtensionRequestProto.RequestType requestType, @Nullable String uniqueId) {
+        ExtensionRequestProto.ExtensionRequest.Builder builder = ExtensionRequestProto.ExtensionRequest.newBuilder();
+        if (uniqueId != null) {
+            builder.setIdentity(ExtensionIdentityProto.ExtensionIdentity.newBuilder().setUniqueId(uniqueId).build());
+        }
+        this.request = builder.setRequestType(requestType).build();
+    }
+
+    public ExtensionRequest(StreamInput in) throws IOException {
+        super(in);
+        this.request = ExtensionRequestProto.ExtensionRequest.parseFrom(in.readByteArray());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(request.toByteArray());
+    }
+
+    public ExtensionRequestProto.RequestType getRequestType() {
+        return this.request.getRequestType();
+    }
+
+    public String getUniqueId() {
+        return request.getIdentity().getUniqueId();
+    }
+
+    public String toString() {
+        return "ExtensionRequest{" + request.toString() + '}';
+    }
+
+    public ExtensionIdentityProto.ExtensionIdentity getExtensionIdentity() {
+        return request.getIdentity();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ExtensionRequest that = (ExtensionRequest) o;
+        return Objects.equals(request.getRequestType(), that.request.getRequestType())
+            && Objects.equals(request.getIdentity().getUniqueId(), that.request.getIdentity().getUniqueId());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(request.getRequestType(), request.getIdentity().getUniqueId());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionScopedSettings.java b/server/src/main/java/org/opensearch/extensions/ExtensionScopedSettings.java
new file mode 100644
index 0000000000000..0c87ce31df737
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionScopedSettings.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.common.settings.AbstractScopedSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.SettingUpgrader;
+import org.opensearch.common.settings.Settings;
+
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Encapsulates all valid extension level settings.
+ *
+ * @opensearch.internal
+ */
+public final class ExtensionScopedSettings extends AbstractScopedSettings {
+
+    public ExtensionScopedSettings(final Set<Setting<?>> settingsSet) {
+        this(settingsSet, Collections.emptySet());
+    }
+
+    public ExtensionScopedSettings(final Set<Setting<?>> settingsSet, final Set<SettingUpgrader<?>> settingUpgraders) {
+        super(Settings.EMPTY, settingsSet, settingUpgraders, Property.ExtensionScope);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java b/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java
new file mode 100644
index 0000000000000..3e71fb16c10ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java
@@ -0,0 +1,516 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.Version;
+import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterSettingsResponse;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsModule;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.discovery.InitializeExtensionRequest;
+import org.opensearch.discovery.InitializeExtensionResponse;
+import org.opensearch.env.EnvironmentSettingsResponse;
+import org.opensearch.extensions.ExtensionsSettings.Extension;
+import org.opensearch.extensions.action.ExtensionActionRequest;
+import org.opensearch.extensions.action.ExtensionActionResponse;
+import org.opensearch.extensions.action.ExtensionTransportActionsHandler;
+import org.opensearch.extensions.action.RegisterTransportActionsRequest;
+import org.opensearch.extensions.action.RemoteExtensionActionResponse;
+import org.opensearch.extensions.action.TransportActionRequestFromExtension;
+import org.opensearch.extensions.rest.RegisterRestActionsRequest;
+import org.opensearch.extensions.rest.RestActionsRequestHandler;
+import org.opensearch.extensions.settings.CustomSettingsRequestHandler;
+import org.opensearch.extensions.settings.RegisterCustomSettingsRequest;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+
+/**
+ * The main class for managing Extension communication with the OpenSearch Node.
+ *
+ * @opensearch.internal
+ */
+public class ExtensionsManager {
+    public static final String REQUEST_EXTENSION_ACTION_NAME = "internal:discovery/extensions";
+    public static final String REQUEST_EXTENSION_CLUSTER_STATE = "internal:discovery/clusterstate";
+    public static final String REQUEST_EXTENSION_CLUSTER_SETTINGS = "internal:discovery/clustersettings";
+    public static final String REQUEST_EXTENSION_ENVIRONMENT_SETTINGS = "internal:discovery/enviornmentsettings";
+    public static final String REQUEST_EXTENSION_ADD_SETTINGS_UPDATE_CONSUMER = "internal:discovery/addsettingsupdateconsumer";
+    public static final String REQUEST_EXTENSION_UPDATE_SETTINGS = "internal:discovery/updatesettings";
+    public static final String REQUEST_EXTENSION_DEPENDENCY_INFORMATION = "internal:discovery/dependencyinformation";
+    public static final String REQUEST_EXTENSION_REGISTER_CUSTOM_SETTINGS = "internal:discovery/registercustomsettings";
+    public static final String REQUEST_EXTENSION_REGISTER_REST_ACTIONS = "internal:discovery/registerrestactions";
+    public static final String REQUEST_EXTENSION_REGISTER_TRANSPORT_ACTIONS = "internal:discovery/registertransportactions";
+    public static final String REQUEST_REST_EXECUTE_ON_EXTENSION_ACTION = "internal:extensions/restexecuteonextensiontaction";
+    public static final String REQUEST_EXTENSION_HANDLE_TRANSPORT_ACTION = "internal:extensions/handle-transportaction";
+    public static final String REQUEST_EXTENSION_HANDLE_REMOTE_TRANSPORT_ACTION = "internal:extensions/handle-remote-transportaction";
+    public static final String TRANSPORT_ACTION_REQUEST_FROM_EXTENSION = "internal:extensions/request-transportaction-from-extension";
+    public static final int EXTENSION_REQUEST_WAIT_TIMEOUT = 10;
+    private static final Logger logger = LogManager.getLogger(ExtensionsManager.class);
+
+    /**
+     * Enum for OpenSearch Requests
+     *
+     * @opensearch.internal
+     */
+    public static enum OpenSearchRequestType {
+        REQUEST_OPENSEARCH_NAMED_WRITEABLE_REGISTRY
+    }
+
+    private ExtensionTransportActionsHandler extensionTransportActionsHandler;
+    private Map<String, Extension> extensionSettingsMap;
+    private Map<String, DiscoveryExtensionNode> initializedExtensions;
+    private Map<String, DiscoveryExtensionNode> extensionIdMap;
+    private RestActionsRequestHandler restActionsRequestHandler;
+    private CustomSettingsRequestHandler customSettingsRequestHandler;
+    private TransportService transportService;
+    private ClusterService clusterService;
+    private final Set<Setting<?>> additionalSettings;
+    private Settings environmentSettings;
+    private AddSettingsUpdateConsumerRequestHandler addSettingsUpdateConsumerRequestHandler;
+    private NodeClient client;
+
+    /**
+     * Instantiate a new ExtensionsManager object to handle requests and responses from extensions. This is called during Node bootstrap.
+     *
+     * @param additionalSettings  Additional settings to read in from extension initialization request
+     * @throws IOException  If the extensions discovery file is not properly retrieved.
+     */
+    public ExtensionsManager(Set<Setting<?>> additionalSettings) throws IOException {
+        logger.info("ExtensionsManager initialized");
+        this.initializedExtensions = new HashMap<String, DiscoveryExtensionNode>();
+        this.extensionIdMap = new HashMap<String, DiscoveryExtensionNode>();
+        this.extensionSettingsMap = new HashMap<String, Extension>();
+        // will be initialized in initializeServicesAndRestHandler which is called after the Node is initialized
+        this.transportService = null;
+        this.clusterService = null;
+        // Settings added to extensions.yml by ExtensionAwarePlugins, such as security settings
+        this.additionalSettings = new HashSet<>();
+        if (additionalSettings != null) {
+            this.additionalSettings.addAll(additionalSettings);
+        }
+        this.client = null;
+        this.extensionTransportActionsHandler = null;
+    }
+
+    /**
+     * Initializes the {@link RestActionsRequestHandler}, {@link TransportService}, {@link ClusterService} and environment settings. This is called during Node bootstrap.
+     * Lists/maps of extensions have already been initialized but not yet populated.
+     *
+     * @param actionModule The ActionModule with the RestController and DynamicActionModule
+     * @param settingsModule The module that binds the provided settings to interface.
+     * @param transportService  The Node's transport service.
+     * @param clusterService  The Node's cluster service.
+     * @param initialEnvironmentSettings The finalized view of settings for the Environment
+     * @param client The client used to make transport requests
+     */
+    public void initializeServicesAndRestHandler(
+        ActionModule actionModule,
+        SettingsModule settingsModule,
+        TransportService transportService,
+        ClusterService clusterService,
+        Settings initialEnvironmentSettings,
+        NodeClient client
+    ) {
+        this.restActionsRequestHandler = new RestActionsRequestHandler(actionModule.getRestController(), extensionIdMap, transportService);
+        this.customSettingsRequestHandler = new CustomSettingsRequestHandler(settingsModule);
+        this.transportService = transportService;
+        this.clusterService = clusterService;
+        this.environmentSettings = initialEnvironmentSettings;
+        this.addSettingsUpdateConsumerRequestHandler = new AddSettingsUpdateConsumerRequestHandler(
+            clusterService,
+            transportService,
+            REQUEST_EXTENSION_UPDATE_SETTINGS
+        );
+        this.client = client;
+        this.extensionTransportActionsHandler = new ExtensionTransportActionsHandler(
+            extensionIdMap,
+            transportService,
+            client,
+            actionModule,
+            this
+        );
+        registerRequestHandler(actionModule.getDynamicActionRegistry());
+    }
+
+    /**
+     * Lookup an initialized extension by its unique id
+     *
+     * @param extensionId The unique extension identifier
+     * @return An optional of the DiscoveryExtensionNode instance for the matching extension
+     */
+    public Optional<DiscoveryExtensionNode> lookupInitializedExtensionById(final String extensionId) {
+        return Optional.ofNullable(this.initializedExtensions.get(extensionId));
+    }
+
+    /**
+     * Lookup the settings for an extension based on unique id for the settings placed in extensions.yml
+     *
+     * @param extensionId The unique extension identifier
+     * @return An optional of the Extension instance for the matching extension
+     */
+    public Optional<Extension> lookupExtensionSettingsById(final String extensionId) {
+        return Optional.ofNullable(this.extensionSettingsMap.get(extensionId));
+    }
+
+    /**
+     * Handles Transport Request from {@link org.opensearch.extensions.action.ExtensionTransportAction} which was invoked by an extension via {@link ExtensionTransportActionsHandler}.
+     *
+     * @param request which was sent by an extension.
+     */
+    public RemoteExtensionActionResponse handleRemoteTransportRequest(ExtensionActionRequest request) throws Exception {
+        return extensionTransportActionsHandler.sendRemoteTransportRequestToExtension(request);
+    }
+
+    /**
+     * Handles Transport Request from {@link org.opensearch.extensions.action.ExtensionTransportAction} which was invoked by OpenSearch or a plugin
+     *
+     * @param request which was sent by an extension.
+     */
+    public ExtensionActionResponse handleTransportRequest(ExtensionActionRequest request) throws Exception {
+        return extensionTransportActionsHandler.sendTransportRequestToExtension(request);
+    }
+
+    private void registerRequestHandler(DynamicActionRegistry dynamicActionRegistry) {
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_REGISTER_REST_ACTIONS,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            RegisterRestActionsRequest::new,
+            ((request, channel, task) -> channel.sendResponse(
+                restActionsRequestHandler.handleRegisterRestActionsRequest(request, dynamicActionRegistry)
+            ))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_REGISTER_CUSTOM_SETTINGS,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            RegisterCustomSettingsRequest::new,
+            ((request, channel, task) -> channel.sendResponse(customSettingsRequestHandler.handleRegisterCustomSettingsRequest(request)))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_CLUSTER_STATE,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            ExtensionRequest::new,
+            ((request, channel, task) -> channel.sendResponse(handleExtensionRequest(request)))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_CLUSTER_SETTINGS,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            ExtensionRequest::new,
+            ((request, channel, task) -> channel.sendResponse(handleExtensionRequest(request)))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_ENVIRONMENT_SETTINGS,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            ExtensionRequest::new,
+            ((request, channel, task) -> channel.sendResponse(handleExtensionRequest(request)))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_DEPENDENCY_INFORMATION,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            ExtensionRequest::new,
+            ((request, channel, task) -> channel.sendResponse(handleExtensionRequest(request)))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_ADD_SETTINGS_UPDATE_CONSUMER,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            AddSettingsUpdateConsumerRequest::new,
+            ((request, channel, task) -> channel.sendResponse(
+                addSettingsUpdateConsumerRequestHandler.handleAddSettingsUpdateConsumerRequest(request)
+            ))
+        );
+        transportService.registerRequestHandler(
+            REQUEST_EXTENSION_REGISTER_TRANSPORT_ACTIONS,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            RegisterTransportActionsRequest::new,
+            ((request, channel, task) -> channel.sendResponse(
+                extensionTransportActionsHandler.handleRegisterTransportActionsRequest(request)
+            ))
+        );
+        transportService.registerRequestHandler(
+            TRANSPORT_ACTION_REQUEST_FROM_EXTENSION,
+            ThreadPool.Names.GENERIC,
+            false,
+            false,
+            TransportActionRequestFromExtension::new,
+            ((request, channel, task) -> channel.sendResponse(
+                extensionTransportActionsHandler.handleTransportActionRequestFromExtension(request)
+            ))
+        );
+    }
+
+    /**
+     * Loads a single extension
+     * @param extension The extension to be loaded
+     */
+    public DiscoveryExtensionNode loadExtension(Extension extension) throws IOException {
+        validateExtension(extension);
+        DiscoveryExtensionNode discoveryExtensionNode = new DiscoveryExtensionNode(
+            extension.getName(),
+            extension.getUniqueId(),
+            new TransportAddress(InetAddress.getByName(extension.getHostAddress()), Integer.parseInt(extension.getPort())),
+            new HashMap<String, String>(),
+            Version.fromString(extension.getOpensearchVersion()),
+            Version.fromString(extension.getMinimumCompatibleVersion()),
+            extension.getDependencies()
+        );
+        extensionIdMap.put(extension.getUniqueId(), discoveryExtensionNode);
+        extensionSettingsMap.put(extension.getUniqueId(), extension);
+        logger.info("Loaded extension with uniqueId " + extension.getUniqueId() + ": " + extension);
+        return discoveryExtensionNode;
+    }
+
+    public void initializeExtension(Extension extension) throws IOException {
+        DiscoveryExtensionNode node = loadExtension(extension);
+        initializeExtensionNode(node);
+    }
+
+    private void validateField(String fieldName, String value) throws IOException {
+        if (Strings.isNullOrEmpty(value)) {
+            throw new IOException("Required field [" + fieldName + "] is missing in the request");
+        }
+    }
+
+    private void validateExtension(Extension extension) throws IOException {
+        validateField("extension name", extension.getName());
+        validateField("extension uniqueId", extension.getUniqueId());
+        validateField("extension host address", extension.getHostAddress());
+        validateField("extension port", extension.getPort());
+        validateField("extension version", extension.getVersion());
+        validateField("opensearch version", extension.getOpensearchVersion());
+        validateField("minimum opensearch version", extension.getMinimumCompatibleVersion());
+        if (extensionIdMap.containsKey(extension.getUniqueId())) {
+            throw new IOException("Duplicate uniqueId [" + extension.getUniqueId() + "]. Did not load extension: " + extension);
+        }
+    }
+
+    /**
+     * Iterate through all extensions and initialize them.  Initialized extensions will be added to the {@link #initializedExtensions}.
+     */
+    public void initialize() {
+        for (DiscoveryExtensionNode extension : extensionIdMap.values()) {
+            initializeExtensionNode(extension);
+        }
+    }
+
+    public void initializeExtensionNode(DiscoveryExtensionNode extensionNode) {
+
+        final CompletableFuture<InitializeExtensionResponse> inProgressFuture = new CompletableFuture<>();
+        final TransportResponseHandler<InitializeExtensionResponse> initializeExtensionResponseHandler = new TransportResponseHandler<
+            InitializeExtensionResponse>() {
+
+            @Override
+            public InitializeExtensionResponse read(StreamInput in) throws IOException {
+                return new InitializeExtensionResponse(in);
+            }
+
+            @Override
+            public void handleResponse(InitializeExtensionResponse response) {
+                for (DiscoveryExtensionNode extension : extensionIdMap.values()) {
+                    if (extension.getName().equals(response.getName())) {
+                        extension.setImplementedInterfaces(response.getImplementedInterfaces());
+                        initializedExtensions.put(extension.getId(), extension);
+                        logger.info("Initialized extension: " + extension.getName());
+                        break;
+                    }
+                }
+                inProgressFuture.complete(response);
+            }
+
+            @Override
+            public void handleException(TransportException exp) {
+                logger.error(new ParameterizedMessage("Extension initialization failed"), exp);
+                inProgressFuture.completeExceptionally(exp);
+            }
+
+            @Override
+            public String executor() {
+                return ThreadPool.Names.GENERIC;
+            }
+        };
+
+        logger.info("Sending extension request type: " + REQUEST_EXTENSION_ACTION_NAME);
+        transportService.getThreadPool().generic().execute(new AbstractRunnable() {
+            @Override
+            public void onFailure(Exception e) {
+                logger.warn("Error registering extension: " + extensionNode.getId(), e);
+                extensionIdMap.remove(extensionNode.getId());
+                if (e.getCause() instanceof ConnectTransportException) {
+                    logger.info("No response from extension to request.", e);
+                    throw (ConnectTransportException) e.getCause();
+                } else if (e.getCause() instanceof RuntimeException) {
+                    throw (RuntimeException) e.getCause();
+                } else if (e.getCause() instanceof Error) {
+                    throw (Error) e.getCause();
+                } else {
+                    throw new RuntimeException(e.getCause());
+                }
+            }
+
+            @Override
+            protected void doRun() throws Exception {
+                transportService.connectToExtensionNode(extensionNode);
+                transportService.sendRequest(
+                    extensionNode,
+                    REQUEST_EXTENSION_ACTION_NAME,
+                    new InitializeExtensionRequest(transportService.getLocalNode(), extensionNode),
+                    initializeExtensionResponseHandler
+                );
+            }
+        });
+    }
+
+    /**
+     * Handles an {@link ExtensionRequest}.
+     *
+     * @param extensionRequest  The request to handle, of a type defined in the {@link org.opensearch.extensions.proto.ExtensionRequestProto.RequestType} enum.
+     * @return  an Response matching the request.
+     * @throws Exception if the request is not handled properly.
+     */
+    TransportResponse handleExtensionRequest(ExtensionRequest extensionRequest) throws Exception {
+        switch (extensionRequest.getRequestType()) {
+            case REQUEST_EXTENSION_CLUSTER_STATE:
+                return new ClusterStateResponse(clusterService.getClusterName(), clusterService.state(), false);
+            case REQUEST_EXTENSION_CLUSTER_SETTINGS:
+                return new ClusterSettingsResponse(clusterService);
+            case REQUEST_EXTENSION_ENVIRONMENT_SETTINGS:
+                return new EnvironmentSettingsResponse(this.environmentSettings);
+            case REQUEST_EXTENSION_DEPENDENCY_INFORMATION:
+                String uniqueId = extensionRequest.getUniqueId();
+                if (uniqueId == null) {
+                    return new ExtensionDependencyResponse(
+                        initializedExtensions.entrySet().stream().map(e -> e.getValue()).collect(Collectors.toList())
+                    );
+                } else {
+                    ExtensionDependency matchingId = new ExtensionDependency(uniqueId, Version.CURRENT);
+                    return new ExtensionDependencyResponse(
+                        initializedExtensions.entrySet()
+                            .stream()
+                            .map(e -> e.getValue())
+                            .filter(e -> e.dependenciesContain(matchingId))
+                            .collect(Collectors.toList())
+                    );
+                }
+            default:
+                throw new IllegalArgumentException("Handler not present for the provided request");
+        }
+    }
+
+    static String getRequestExtensionActionName() {
+        return REQUEST_EXTENSION_ACTION_NAME;
+    }
+
+    static String getRequestExtensionClusterState() {
+        return REQUEST_EXTENSION_CLUSTER_STATE;
+    }
+
+    static String getRequestExtensionClusterSettings() {
+        return REQUEST_EXTENSION_CLUSTER_SETTINGS;
+    }
+
+    static Logger getLogger() {
+        return logger;
+    }
+
+    TransportService getTransportService() {
+        return transportService;
+    }
+
+    ClusterService getClusterService() {
+        return clusterService;
+    }
+
+    Map<String, DiscoveryExtensionNode> getExtensionIdMap() {
+        return extensionIdMap;
+    }
+
+    RestActionsRequestHandler getRestActionsRequestHandler() {
+        return restActionsRequestHandler;
+    }
+
+    void setExtensionIdMap(Map<String, DiscoveryExtensionNode> extensionIdMap) {
+        this.extensionIdMap = extensionIdMap;
+    }
+
+    void setRestActionsRequestHandler(RestActionsRequestHandler restActionsRequestHandler) {
+        this.restActionsRequestHandler = restActionsRequestHandler;
+    }
+
+    void setTransportService(TransportService transportService) {
+        this.transportService = transportService;
+    }
+
+    void setClusterService(ClusterService clusterService) {
+        this.clusterService = clusterService;
+    }
+
+    CustomSettingsRequestHandler getCustomSettingsRequestHandler() {
+        return customSettingsRequestHandler;
+    }
+
+    void setCustomSettingsRequestHandler(CustomSettingsRequestHandler customSettingsRequestHandler) {
+        this.customSettingsRequestHandler = customSettingsRequestHandler;
+    }
+
+    AddSettingsUpdateConsumerRequestHandler getAddSettingsUpdateConsumerRequestHandler() {
+        return addSettingsUpdateConsumerRequestHandler;
+    }
+
+    void setAddSettingsUpdateConsumerRequestHandler(AddSettingsUpdateConsumerRequestHandler addSettingsUpdateConsumerRequestHandler) {
+        this.addSettingsUpdateConsumerRequestHandler = addSettingsUpdateConsumerRequestHandler;
+    }
+
+    Settings getEnvironmentSettings() {
+        return environmentSettings;
+    }
+
+    public Set<Setting<?>> getAdditionalSettings() {
+        return this.additionalSettings;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionsSettings.java b/server/src/main/java/org/opensearch/extensions/ExtensionsSettings.java
new file mode 100644
index 0000000000000..9d21469c8fa28
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionsSettings.java
@@ -0,0 +1,179 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * List of extension configurations from extension.yml
+ *
+ * @opensearch.internal
+ */
+public class ExtensionsSettings {
+
+    private List<Extension> extensions;
+
+    public ExtensionsSettings(List<Extension> extensions) {
+        this.extensions = extensions;
+    }
+
+    public ExtensionsSettings() {
+        extensions = new ArrayList<Extension>();
+    }
+
+    /**
+     * Extension configuration used for extension discovery
+     *
+     * @opensearch.internal
+    */
+    public static class Extension {
+
+        private String name;
+        private String uniqueId;
+        private String hostAddress;
+        private String port;
+        private String version;
+        private String opensearchVersion;
+        private String minimumCompatibleVersion;
+        private List<ExtensionDependency> dependencies = Collections.emptyList();
+        private ExtensionScopedSettings additionalSettings;
+
+        public Extension(
+            String name,
+            String uniqueId,
+            String hostAddress,
+            String port,
+            String version,
+            String opensearchVersion,
+            String minimumCompatibleVersion,
+            List<ExtensionDependency> dependencies,
+            ExtensionScopedSettings additionalSettings
+        ) {
+            this.name = name;
+            this.uniqueId = uniqueId;
+            this.hostAddress = hostAddress;
+            this.port = port;
+            this.version = version;
+            this.opensearchVersion = opensearchVersion;
+            this.minimumCompatibleVersion = minimumCompatibleVersion;
+            this.dependencies = dependencies;
+            this.additionalSettings = additionalSettings;
+        }
+
+        public Extension() {
+            name = "";
+            uniqueId = "";
+            hostAddress = "";
+            port = "";
+            version = "";
+            opensearchVersion = "";
+            minimumCompatibleVersion = "";
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public String getUniqueId() {
+            return uniqueId;
+        }
+
+        public void setUniqueId(String uniqueId) {
+            this.uniqueId = uniqueId;
+        }
+
+        public String getHostAddress() {
+            return hostAddress;
+        }
+
+        public void setHostAddress(String hostAddress) {
+            this.hostAddress = hostAddress;
+        }
+
+        public String getPort() {
+            return port;
+        }
+
+        public void setPort(String port) {
+            this.port = port;
+        }
+
+        public String getVersion() {
+            return version;
+        }
+
+        public void setVersion(String version) {
+            this.version = version;
+        }
+
+        public String getOpensearchVersion() {
+            return opensearchVersion;
+        }
+
+        public void setOpensearchVersion(String opensearchVersion) {
+            this.opensearchVersion = opensearchVersion;
+        }
+
+        public List<ExtensionDependency> getDependencies() {
+            return dependencies;
+        }
+
+        public ExtensionScopedSettings getAdditionalSettings() {
+            return additionalSettings;
+        }
+
+        public String getMinimumCompatibleVersion() {
+            return minimumCompatibleVersion;
+        }
+
+        public void setMinimumCompatibleVersion(String minimumCompatibleVersion) {
+            this.minimumCompatibleVersion = minimumCompatibleVersion;
+        }
+
+        @Override
+        public String toString() {
+            return "Extension [name="
+                + name
+                + ", uniqueId="
+                + uniqueId
+                + ", hostAddress="
+                + hostAddress
+                + ", port="
+                + port
+                + ", version="
+                + version
+                + ", opensearchVersion="
+                + opensearchVersion
+                + ", minimumCompatibleVersion="
+                + minimumCompatibleVersion
+                + "]";
+        }
+
+    }
+
+    public List<Extension> getExtensions() {
+        return extensions;
+    }
+
+    public void setExtensions(List<Extension> extensions) {
+        this.extensions = extensions;
+    }
+
+    @Override
+    public String toString() {
+        return "ExtensionsSettings [extensions=" + extensions + "]";
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/NoopExtensionsManager.java b/server/src/main/java/org/opensearch/extensions/NoopExtensionsManager.java
new file mode 100644
index 0000000000000..327dce187059c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/NoopExtensionsManager.java
@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.action.ActionModule;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsModule;
+import org.opensearch.extensions.action.ExtensionActionRequest;
+import org.opensearch.extensions.action.ExtensionActionResponse;
+import org.opensearch.extensions.action.RemoteExtensionActionResponse;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Optional;
+import java.util.Set;
+
+/**
+ * Noop class for ExtensionsManager
+ *
+ * @opensearch.internal
+ */
+public class NoopExtensionsManager extends ExtensionsManager {
+
+    public NoopExtensionsManager() throws IOException {
+        super(Set.of());
+    }
+
+    @Override
+    public void initializeServicesAndRestHandler(
+        ActionModule actionModule,
+        SettingsModule settingsModule,
+        TransportService transportService,
+        ClusterService clusterService,
+        Settings initialEnvironmentSettings,
+        NodeClient client
+    ) {
+        // no-op
+    }
+
+    @Override
+    public RemoteExtensionActionResponse handleRemoteTransportRequest(ExtensionActionRequest request) throws Exception {
+        // no-op empty response
+        return new RemoteExtensionActionResponse(true, new byte[0]);
+    }
+
+    @Override
+    public ExtensionActionResponse handleTransportRequest(ExtensionActionRequest request) throws Exception {
+        // no-op empty response
+        return new ExtensionActionResponse(new byte[0]);
+    }
+
+    @Override
+    public void initialize() {
+        // no-op
+    }
+
+    @Override
+    public Optional<DiscoveryExtensionNode> lookupInitializedExtensionById(final String extensionId) {
+        // no-op not found
+        return Optional.empty();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/OpenSearchRequest.java b/server/src/main/java/org/opensearch/extensions/OpenSearchRequest.java
new file mode 100644
index 0000000000000..63ddfdc91eb7a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/OpenSearchRequest.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request from OpenSearch to an Extension
+ *
+ * @opensearch.internal
+ */
+public class OpenSearchRequest extends TransportRequest {
+
+    private static final Logger logger = LogManager.getLogger(OpenSearchRequest.class);
+    private ExtensionsManager.OpenSearchRequestType requestType;
+
+    /**
+     * @param requestType String identifying the default extension point to invoke on the extension
+     */
+    public OpenSearchRequest(ExtensionsManager.OpenSearchRequestType requestType) {
+        this.requestType = requestType;
+    }
+
+    /**
+     * @param in StreamInput from which a string identifying the default extension point to invoke on the extension is read from
+     */
+    public OpenSearchRequest(StreamInput in) throws IOException {
+        super(in);
+        this.requestType = in.readEnum(ExtensionsManager.OpenSearchRequestType.class);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeEnum(requestType);
+    }
+
+    @Override
+    public String toString() {
+        return "OpenSearchRequest{" + "requestType=" + requestType + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        OpenSearchRequest that = (OpenSearchRequest) o;
+        return Objects.equals(requestType, that.requestType);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(requestType);
+    }
+
+    public ExtensionsManager.OpenSearchRequestType getRequestType() {
+        return this.requestType;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/UpdateSettingsRequest.java b/server/src/main/java/org/opensearch/extensions/UpdateSettingsRequest.java
new file mode 100644
index 0000000000000..0295269b1787f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/UpdateSettingsRequest.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.WriteableSetting;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Update Settings Request for Extensibility
+ *
+ * @opensearch.internal
+ */
+public class UpdateSettingsRequest extends TransportRequest {
+    private static final Logger logger = LogManager.getLogger(UpdateSettingsRequest.class);
+
+    private WriteableSetting.SettingType settingType;
+    private Setting<?> componentSetting;
+    private Object data;
+
+    public UpdateSettingsRequest(WriteableSetting.SettingType settingType, Setting<?> componentSetting, Object data) {
+        this.settingType = settingType;
+        this.componentSetting = componentSetting;
+        this.data = data;
+    }
+
+    public UpdateSettingsRequest(StreamInput in) throws IOException {
+        super(in);
+        this.settingType = in.readEnum(WriteableSetting.SettingType.class);
+        this.componentSetting = new WriteableSetting(in).getSetting();
+        this.data = in.readGenericValue();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeEnum(settingType);
+        new WriteableSetting(componentSetting).writeTo(out);
+        out.writeGenericValue(this.data);
+    }
+
+    public WriteableSetting.SettingType getSettingType() {
+        return this.settingType;
+    }
+
+    public Setting<?> getComponentSetting() {
+        return this.componentSetting;
+    }
+
+    public Object getData() {
+        return this.data;
+    }
+
+    @Override
+    public String toString() {
+        return "UpdateSettingRequest{settingType="
+            + this.settingType.toString()
+            + "componentSetting="
+            + this.componentSetting.toString()
+            + ", data="
+            + this.data.toString()
+            + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        UpdateSettingsRequest that = (UpdateSettingsRequest) obj;
+        return Objects.equals(settingType, that.settingType)
+            && Objects.equals(componentSetting, that.componentSetting)
+            && Objects.equals(data, that.data);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(settingType, componentSetting, data);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/UpdateSettingsResponseHandler.java b/server/src/main/java/org/opensearch/extensions/UpdateSettingsResponseHandler.java
new file mode 100644
index 0000000000000..8c7c3c4cb9bd9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/UpdateSettingsResponseHandler.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+
+import java.io.IOException;
+
+/**
+ * Response handler for {@link UpdateSettingsRequest}
+ *
+ * @opensearch.internal
+ */
+public class UpdateSettingsResponseHandler implements TransportResponseHandler<AcknowledgedResponse> {
+    private static final Logger logger = LogManager.getLogger(UpdateSettingsResponseHandler.class);
+
+    @Override
+    public AcknowledgedResponse read(StreamInput in) throws IOException {
+        return new AcknowledgedResponse(in);
+    }
+
+    @Override
+    public void handleResponse(AcknowledgedResponse response) {
+        logger.info("response {}", response.getStatus());
+        if (!response.getStatus()) {
+            handleException(new TransportException("Request was not completed successfully"));
+        }
+    }
+
+    @Override
+    public void handleException(TransportException exp) {
+        logger.error(new ParameterizedMessage("UpdateSettingsRequest failed"), exp);
+    }
+
+    @Override
+    public String executor() {
+        return ThreadPool.Names.GENERIC;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionAction.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionAction.java
new file mode 100644
index 0000000000000..658c114d73c1a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionAction.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.ActionType;
+
+import java.util.Objects;
+
+/**
+ * An {@link ActionType} to be used in extension action transport handling.
+ *
+ * @opensearch.internal
+ */
+public class ExtensionAction extends ActionType<RemoteExtensionActionResponse> {
+
+    private final String uniqueId;
+
+    /**
+     * Create an instance of this action to register in the dynamic actions map.
+     *
+     * @param uniqueId The uniqueId of the extension which will run this action.
+     * @param name The fully qualified class name of the extension's action to execute.
+     */
+    public ExtensionAction(String uniqueId, String name) {
+        super(name, RemoteExtensionActionResponse::new);
+        this.uniqueId = uniqueId;
+    }
+
+    /**
+     * Gets the uniqueId of the extension which will run this action.
+     *
+     * @return the uniqueId
+     */
+    public String uniqueId() {
+        return this.uniqueId;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = super.hashCode();
+        result = prime * result + Objects.hash(uniqueId);
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!super.equals(obj)) return false;
+        if (getClass() != obj.getClass()) return false;
+        ExtensionAction other = (ExtensionAction) obj;
+        return Objects.equals(uniqueId, other.uniqueId);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionActionRequest.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionRequest.java
new file mode 100644
index 0000000000000..30a864f3f5fcf
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionRequest.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionTransportMessageProto.ExtensionTransportMessage;
+
+import java.io.IOException;
+
+/**
+ * This class translates Extension transport request to ActionRequest
+ * which is internally used to make transport action call.
+ *
+ * @opensearch.internal
+ */
+public class ExtensionActionRequest extends ActionRequest {
+    private final ExtensionTransportMessage request;
+
+    /**
+     * ExtensionActionRequest constructor.
+     *
+     * @param action is the transport action intended to be invoked which is registered by an extension via {@link ExtensionTransportActionsHandler}.
+     * @param requestBytes is the raw bytes being transported between extensions.
+     */
+    public ExtensionActionRequest(String action, ByteString requestBytes) {
+        this.request = ExtensionTransportMessage.newBuilder().setAction(action).setRequestBytes(requestBytes).build();
+    }
+
+    /**
+     * ExtensionActionRequest constructor from {@link StreamInput}.
+     *
+     * @param in bytes stream input used to de-serialize the message.
+     * @throws IOException when message de-serialization fails.
+     */
+    public ExtensionActionRequest(StreamInput in) throws IOException {
+        super(in);
+        this.request = ExtensionTransportMessage.parseFrom(in.readByteArray());
+    }
+
+    public String getAction() {
+        return request.getAction();
+    }
+
+    public ByteString getRequestBytes() {
+        return request.getRequestBytes();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(request.toByteArray());
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionActionResponse.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionResponse.java
new file mode 100644
index 0000000000000..5f0ba572b2ea6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionResponse.java
@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * This class encapsulates the transport response from extension
+ *
+ * @opensearch.internal
+ */
+public class ExtensionActionResponse extends ActionResponse {
+    /**
+     * responseBytes is the raw bytes being transported between extensions.
+     */
+    private byte[] responseBytes;
+
+    /**
+     * ExtensionActionResponse constructor.
+     *
+     * @param responseBytes is the raw bytes being transported between extensions.
+     */
+    public ExtensionActionResponse(byte[] responseBytes) {
+        this.responseBytes = responseBytes;
+    }
+
+    /**
+     * ExtensionActionResponse constructor from {@link StreamInput}.
+     *
+     * @param in bytes stream input used to de-serialize the message.
+     * @throws IOException when message de-serialization fails.
+     */
+    public ExtensionActionResponse(StreamInput in) throws IOException {
+        responseBytes = in.readByteArray();
+    }
+
+    public byte[] getResponseBytes() {
+        return responseBytes;
+    }
+
+    public void setResponseBytes(byte[] responseBytes) {
+        this.responseBytes = responseBytes;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeByteArray(responseBytes);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionActionUtil.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionUtil.java
new file mode 100644
index 0000000000000..93d8ff548f7fc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionActionUtil.java
@@ -0,0 +1,117 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+
+/**
+ * ExtensionActionUtil - a class for creating and processing remote requests using byte arrays.
+ */
+public class ExtensionActionUtil {
+
+    /**
+     * The Unicode UNIT SEPARATOR used to separate the Request class name and parameter bytes
+     */
+    public static final byte UNIT_SEPARATOR = (byte) '\u001F';
+
+    /**
+     * @param request an instance of a request extending {@link ActionRequest}, containing information about the
+     * request being sent to the remote server. It is used to create a byte array containing the request data,
+     * which will be sent to the remote server.
+     * @return An Extension ActionRequest object that represents the deserialized data.
+     * If an error occurred during the deserialization process, the method will return {@code null}.
+     * @throws  RuntimeException If a RuntimeException occurs while creating the proxy request bytes.
+     */
+    public static byte[] createProxyRequestBytes(ActionRequest request) throws RuntimeException {
+        byte[] requestClassBytes = request.getClass().getName().getBytes(StandardCharsets.UTF_8);
+        byte[] requestBytes;
+
+        try {
+            requestBytes = convertParamsToBytes(request);
+            assert requestBytes != null;
+            return ByteBuffer.allocate(requestClassBytes.length + 1 + requestBytes.length)
+                .put(requestClassBytes)
+                .put(UNIT_SEPARATOR)
+                .put(requestBytes)
+                .array();
+        } catch (RuntimeException e) {
+            throw new RuntimeException("RuntimeException occurred while creating proxyRequestBytes");
+        }
+    }
+
+    /**
+     * @param  requestBytes is a byte array containing the request data, used by the "createActionRequest"
+     * method to create an "ActionRequest" object, which represents the request model to be processed on the server.
+     * @return an "Action Request" object representing the request model for processing on the server,
+     * or {@code null} if the request data is invalid or null.
+     * @throws ReflectiveOperationException if an exception occurs during the reflective operation, such as when
+     *  resolving the request class, accessing the constructor, or creating an instance  using reflection
+     * @throws NullPointerException if a null pointer exception occurs during the creation of the ActionRequest object
+     */
+    public static ActionRequest createActionRequest(byte[] requestBytes) throws ReflectiveOperationException {
+        int delimPos = delimPos(requestBytes);
+        String requestClassName = new String(Arrays.copyOfRange(requestBytes, 0, delimPos + 1), StandardCharsets.UTF_8).stripTrailing();
+        try {
+            Class<?> clazz = Class.forName(requestClassName);
+            Constructor<?> constructor = clazz.getConstructor(StreamInput.class);
+            StreamInput requestByteStream = StreamInput.wrap(Arrays.copyOfRange(requestBytes, delimPos + 1, requestBytes.length));
+            return (ActionRequest) constructor.newInstance(requestByteStream);
+        } catch (ReflectiveOperationException e) {
+            throw new ReflectiveOperationException(
+                "ReflectiveOperationException occurred while creating extensionAction request from bytes",
+                e
+            );
+        } catch (NullPointerException e) {
+            throw new NullPointerException(
+                "NullPointerException occurred while creating extensionAction request from bytes" + e.getMessage()
+            );
+        }
+    }
+
+    /**
+     * Converts the given object of type T, which implements the {@link Writeable} interface, to a byte array.
+     * @param <T> the type of the object to be converted to bytes, which must implement the {@link Writeable} interface.
+     * @param writeableObject the object of type T to be converted to bytes.
+     * @return a byte array containing the serialized bytes of the given object, or {@code null} if the input is invalid or null.
+     * @throws IllegalStateException if a failure occurs while writing the data
+     */
+    public static <T extends Writeable> byte[] convertParamsToBytes(T writeableObject) throws IllegalStateException {
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            writeableObject.writeTo(out);
+            return BytesReference.toBytes(out.bytes());
+        } catch (IOException ieo) {
+            throw new IllegalStateException("Failure writing bytes", ieo);
+        }
+    }
+
+    /**
+     * Searches for the position of the unit separator byte in the given byte array.
+     *
+     * @param bytes the byte array to search for the unit separator byte.
+     * @return the index of the unit separator byte in the byte array, or -1 if it was not found.
+     */
+    public static int delimPos(byte[] bytes) {
+        for (int offset = 0; offset < bytes.length; ++offset) {
+            if (bytes[offset] == ExtensionActionUtil.UNIT_SEPARATOR) {
+                return offset;
+            }
+        }
+        return -1;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionHandleTransportRequest.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionHandleTransportRequest.java
new file mode 100644
index 0000000000000..02b2a8061baa4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionHandleTransportRequest.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionTransportMessageProto.ExtensionTransportMessage;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * This class encapsulates a transport request to extension
+ *
+ * @opensearch.api
+ */
+public class ExtensionHandleTransportRequest extends TransportRequest {
+    private final ExtensionTransportMessage request;
+
+    /**
+     * ExtensionHandleTransportRequest constructor.
+     *
+     * @param action is the transport action intended to be invoked which is registered by an extension via {@link ExtensionTransportActionsHandler}.
+     * @param requestBytes is the raw bytes being transported between extensions.
+     */
+    public ExtensionHandleTransportRequest(String action, ByteString requestBytes) {
+        this.request = ExtensionTransportMessage.newBuilder().setAction(action).setRequestBytes(requestBytes).build();
+    }
+
+    /**
+     * ExtensionHandleTransportRequest constructor from {@link StreamInput}.
+     *
+     * @param in bytes stream input used to de-serialize the message.
+     * @throws IOException when message de-serialization fails.
+     */
+    public ExtensionHandleTransportRequest(StreamInput in) throws IOException {
+        super(in);
+        this.request = ExtensionTransportMessage.parseFrom(in.readByteArray());
+    }
+
+    public String getAction() {
+        return this.request.getAction();
+    }
+
+    public ByteString getRequestBytes() {
+        return this.request.getRequestBytes();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(request.toByteArray());
+    }
+
+    @Override
+    public String toString() {
+        return "ExtensionHandleTransportRequest{action=" + request.getAction() + ", requestBytes=" + request.getRequestBytes() + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        ExtensionHandleTransportRequest that = (ExtensionHandleTransportRequest) obj;
+        return Objects.equals(request.getAction(), that.request.getAction())
+            && Objects.equals(request.getRequestBytes(), that.request.getRequestBytes());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(request.getAction(), request.getRequestBytes());
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyAction.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyAction.java
new file mode 100644
index 0000000000000..7345cf44e007f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyAction.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * The main proxy action for all extensions
+ *
+ * @opensearch.internal
+ */
+public class ExtensionProxyAction extends ActionType<ExtensionActionResponse> {
+    public static final String NAME = "cluster:internal/extensions";
+    public static final ExtensionProxyAction INSTANCE = new ExtensionProxyAction();
+
+    public ExtensionProxyAction() {
+        super(NAME, ExtensionActionResponse::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyTransportAction.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyTransportAction.java
new file mode 100644
index 0000000000000..f5ec472c3edc4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionProxyTransportAction.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.tasks.Task;
+import org.opensearch.transport.TransportService;
+
+/**
+ * A proxy transport action used to proxy a transport request from OpenSearch or a plugin to execute on an extension
+ *
+ * @opensearch.internal
+ */
+public class ExtensionProxyTransportAction extends HandledTransportAction<ExtensionActionRequest, ExtensionActionResponse> {
+
+    private final ExtensionsManager extensionsManager;
+
+    @Inject
+    public ExtensionProxyTransportAction(
+        Settings settings,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        ClusterService clusterService,
+        ExtensionsManager extensionsManager
+    ) {
+        super(ExtensionProxyAction.NAME, transportService, actionFilters, ExtensionActionRequest::new);
+        this.extensionsManager = extensionsManager;
+    }
+
+    @Override
+    protected void doExecute(Task task, ExtensionActionRequest request, ActionListener<ExtensionActionResponse> listener) {
+        try {
+            listener.onResponse(extensionsManager.handleTransportRequest(request));
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportAction.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportAction.java
new file mode 100644
index 0000000000000..50a3e0036cbb1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportAction.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.TransportAction;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskManager;
+
+/**
+ * A proxy transport action used to proxy a transport request from an extension to execute on another extension
+ *
+ * @opensearch.internal
+ */
+public class ExtensionTransportAction extends TransportAction<ExtensionActionRequest, RemoteExtensionActionResponse> {
+
+    private final ExtensionsManager extensionsManager;
+
+    public ExtensionTransportAction(
+        String actionName,
+        ActionFilters actionFilters,
+        TaskManager taskManager,
+        ExtensionsManager extensionsManager
+    ) {
+        super(actionName, actionFilters, taskManager);
+        this.extensionsManager = extensionsManager;
+    }
+
+    @Override
+    protected void doExecute(Task task, ExtensionActionRequest request, ActionListener<RemoteExtensionActionResponse> listener) {
+        try {
+            listener.onResponse(extensionsManager.handleRemoteTransportRequest(request));
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java
new file mode 100644
index 0000000000000..ac60df1b73764
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java
@@ -0,0 +1,313 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.extensions.AcknowledgedResponse;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ActionNotFoundTransportException;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * This class manages TransportActions for extensions
+ *
+ * @opensearch.internal
+ */
+public class ExtensionTransportActionsHandler {
+    private static final Logger logger = LogManager.getLogger(ExtensionTransportActionsHandler.class);
+    // Map of action name to Extension unique ID, populated locally
+    private final Map<String, String> actionToIdMap = new ConcurrentHashMap<>();
+    // Map of Extension unique ID to Extension Node, populated in Extensions Manager
+    private final Map<String, DiscoveryExtensionNode> extensionIdMap;
+    private final TransportService transportService;
+    private final NodeClient client;
+    private final ActionFilters actionFilters;
+    private final DynamicActionRegistry dynamicActionRegistry;
+    private final ExtensionsManager extensionsManager;
+
+    public ExtensionTransportActionsHandler(
+        Map<String, DiscoveryExtensionNode> extensionIdMap,
+        TransportService transportService,
+        NodeClient client,
+        ActionModule actionModule,
+        ExtensionsManager extensionsManager
+    ) {
+        this.extensionIdMap = extensionIdMap;
+        this.transportService = transportService;
+        this.client = client;
+        this.actionFilters = actionModule.getActionFilters();
+        this.dynamicActionRegistry = actionModule.getDynamicActionRegistry();
+        this.extensionsManager = extensionsManager;
+    }
+
+    /**
+     * Method to register actions for extensions.
+     *
+     * @param action to be registered.
+     * @param uniqueId id of extension for which action is being registered.
+     * @throws IllegalArgumentException when action being registered already is registered.
+     */
+    void registerAction(String action, String uniqueId) throws IllegalArgumentException {
+        // Register the action in this handler so it knows which extension owns it
+        if (actionToIdMap.putIfAbsent(action, uniqueId) != null) {
+            throw new IllegalArgumentException("The action [" + action + "] you are trying to register is already registered");
+        }
+        // Register the action in the action module's dynamic actions map
+        dynamicActionRegistry.registerDynamicAction(
+            new ExtensionAction(uniqueId, action),
+            new ExtensionTransportAction(action, actionFilters, transportService.getTaskManager(), extensionsManager)
+        );
+    }
+
+    /**
+     * Method to get extension for a given action.
+     *
+     * @param action for which to get the registered extension.
+     * @return the extension or null if not found
+     */
+    public DiscoveryExtensionNode getExtension(String action) {
+        String uniqueId = actionToIdMap.get(action);
+        if (uniqueId == null) {
+            throw new ActionNotFoundTransportException(action);
+        }
+        return extensionIdMap.get(uniqueId);
+    }
+
+    /**
+     * Handles a {@link RegisterTransportActionsRequest}.
+     *
+     * @param transportActionsRequest  The request to handle.
+     * @return  A {@link AcknowledgedResponse} indicating success.
+     */
+    public TransportResponse handleRegisterTransportActionsRequest(RegisterTransportActionsRequest transportActionsRequest) {
+        try {
+            for (String action : transportActionsRequest.getTransportActions()) {
+                registerAction(action, transportActionsRequest.getUniqueId());
+            }
+        } catch (Exception e) {
+            logger.error("Could not register Transport Action: " + e.getMessage());
+            return new AcknowledgedResponse(false);
+        }
+        return new AcknowledgedResponse(true);
+    }
+
+    /**
+     * Method which handles transport action request from an extension.
+     *
+     * @param request from extension.
+     * @return {@link TransportResponse} which is sent back to the transport action invoker.
+     * @throws InterruptedException when message transport fails.
+     */
+    public RemoteExtensionActionResponse handleTransportActionRequestFromExtension(TransportActionRequestFromExtension request)
+        throws Exception {
+        String actionName = request.getAction();
+        String uniqueId = actionToIdMap.get(actionName);
+        final RemoteExtensionActionResponse response = new RemoteExtensionActionResponse(false, new byte[0]);
+        // Fail fast if uniqueId is null
+        if (uniqueId == null) {
+            response.setResponseBytesAsString("Request failed: action [" + actionName + "] is not registered for any extension.");
+            return response;
+        }
+        ExtensionAction extensionAction = new ExtensionAction(uniqueId, actionName);
+        // Validate that this action has been registered
+        if (dynamicActionRegistry.get(extensionAction) == null) {
+            response.setResponseBytesAsString(
+                "Request failed: action [" + actionName + "] is not registered for extension [" + uniqueId + "]."
+            );
+            return response;
+        }
+        DiscoveryExtensionNode extension = extensionIdMap.get(uniqueId);
+        if (extension == null) {
+            response.setResponseBytesAsString("Request failed: extension [" + uniqueId + "] can not be reached.");
+            return response;
+        }
+        final CompletableFuture<RemoteExtensionActionResponse> inProgressFuture = new CompletableFuture<>();
+        client.execute(
+            extensionAction,
+            new ExtensionActionRequest(request.getAction(), request.getRequestBytes()),
+            new ActionListener<RemoteExtensionActionResponse>() {
+                @Override
+                public void onResponse(RemoteExtensionActionResponse actionResponse) {
+                    response.setSuccess(actionResponse.isSuccess());
+                    response.setResponseBytes(actionResponse.getResponseBytes());
+                    inProgressFuture.complete(actionResponse);
+                }
+
+                @Override
+                public void onFailure(Exception exp) {
+                    logger.debug("Transport request failed", exp);
+                    response.setResponseBytesAsString("Request failed: " + exp.getMessage());
+                    inProgressFuture.completeExceptionally(exp);
+                }
+            }
+        );
+        try {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        }
+        return response;
+    }
+
+    /**
+     * Method to send transport action request to an extension to handle.
+     *
+     * @param request to extension to handle transport request.
+     * @return {@link ExtensionActionResponse} which encapsulates the transport response from the extension.
+     * @throws InterruptedException when message transport fails.
+     */
+    public ExtensionActionResponse sendTransportRequestToExtension(ExtensionActionRequest request) throws Exception {
+        DiscoveryExtensionNode extension = getExtension(request.getAction());
+        final CompletableFuture<ExtensionActionResponse> inProgressFuture = new CompletableFuture<>();
+        final ExtensionActionResponse extensionActionResponse = new ExtensionActionResponse(new byte[0]);
+        final TransportResponseHandler<ExtensionActionResponse> extensionActionResponseTransportResponseHandler =
+            new TransportResponseHandler<ExtensionActionResponse>() {
+
+                @Override
+                public ExtensionActionResponse read(StreamInput in) throws IOException {
+                    return new ExtensionActionResponse(in);
+                }
+
+                @Override
+                public void handleResponse(ExtensionActionResponse response) {
+                    extensionActionResponse.setResponseBytes(response.getResponseBytes());
+                    inProgressFuture.complete(response);
+                }
+
+                @Override
+                public void handleException(TransportException exp) {
+                    logger.debug("Transport request failed", exp);
+                    inProgressFuture.completeExceptionally(exp);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.GENERIC;
+                }
+            };
+        try {
+            transportService.sendRequest(
+                extension,
+                ExtensionsManager.REQUEST_EXTENSION_HANDLE_TRANSPORT_ACTION,
+                new ExtensionHandleTransportRequest(request.getAction(), request.getRequestBytes()),
+                extensionActionResponseTransportResponseHandler
+            );
+        } catch (Exception e) {
+            logger.info("Failed to send transport action to extension " + extension.getName(), e);
+        }
+        try {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        }
+        return extensionActionResponse;
+    }
+
+    /**
+     * Method to send transport action request from a remote extension to another extension to handle.
+     *
+     * @param request to extension to handle transport request.
+     * @return {@link RemoteExtensionActionResponse} which encapsulates the transport response from the extension and its success.
+     */
+    public RemoteExtensionActionResponse sendRemoteTransportRequestToExtension(ExtensionActionRequest request) {
+        DiscoveryExtensionNode extension = getExtension(request.getAction());
+        final CompletableFuture<RemoteExtensionActionResponse> inProgressFuture = new CompletableFuture<>();
+        final RemoteExtensionActionResponse extensionActionResponse = new RemoteExtensionActionResponse(false, new byte[0]);
+        final TransportResponseHandler<RemoteExtensionActionResponse> extensionActionResponseTransportResponseHandler =
+            new TransportResponseHandler<RemoteExtensionActionResponse>() {
+
+                @Override
+                public RemoteExtensionActionResponse read(StreamInput in) throws IOException {
+                    return new RemoteExtensionActionResponse(in);
+                }
+
+                @Override
+                public void handleResponse(RemoteExtensionActionResponse response) {
+                    extensionActionResponse.setSuccess(response.isSuccess());
+                    extensionActionResponse.setResponseBytes(response.getResponseBytes());
+                    inProgressFuture.complete(response);
+                }
+
+                @Override
+                public void handleException(TransportException exp) {
+                    logger.debug("Transport request failed", exp);
+                    extensionActionResponse.setResponseBytesAsString("Request failed: " + exp.getMessage());
+                    inProgressFuture.completeExceptionally(exp);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.GENERIC;
+                }
+            };
+        try {
+            transportService.sendRequest(
+                extension,
+                ExtensionsManager.REQUEST_EXTENSION_HANDLE_REMOTE_TRANSPORT_ACTION,
+                new ExtensionHandleTransportRequest(request.getAction(), request.getRequestBytes()),
+                extensionActionResponseTransportResponseHandler
+            );
+        } catch (Exception e) {
+            logger.info("Failed to send transport action to extension " + extension.getName(), e);
+        }
+        try {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        }
+        return extensionActionResponse;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/RegisterTransportActionsRequest.java b/server/src/main/java/org/opensearch/extensions/action/RegisterTransportActionsRequest.java
new file mode 100644
index 0000000000000..7e559f9b948d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/RegisterTransportActionsRequest.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionIdentityProto.ExtensionIdentity;
+import org.opensearch.extensions.proto.RegisterTransportActionsProto.RegisterTransportActions;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Request to register extension Transport actions
+ *
+ * @opensearch.internal
+ */
+public class RegisterTransportActionsRequest extends TransportRequest {
+    private final RegisterTransportActions request;
+
+    public RegisterTransportActionsRequest(String uniqueId, Set<String> transportActions) {
+        ExtensionIdentity identity = ExtensionIdentity.newBuilder().setUniqueId(uniqueId).build();
+        this.request = RegisterTransportActions.newBuilder().setIdentity(identity).addAllTransportActions(transportActions).build();
+    }
+
+    public RegisterTransportActionsRequest(StreamInput in) throws IOException {
+        super(in);
+        this.request = RegisterTransportActions.parseFrom(in.readByteArray());
+    }
+
+    public String getUniqueId() {
+        return request.getIdentity().getUniqueId();
+    }
+
+    public List<String> getTransportActions() {
+        return request.getTransportActionsList();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(request.toByteArray());
+    }
+
+    @Override
+    public String toString() {
+        return "TransportActionsRequest{Identity=" + request.getIdentity() + ", actions=" + request.getTransportActionsList() + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        RegisterTransportActionsRequest that = (RegisterTransportActionsRequest) obj;
+        return Objects.equals(request.getIdentity().getUniqueId(), that.request.getIdentity().getUniqueId())
+            && Objects.equals(request.getTransportActionsList(), that.request.getTransportActionsList());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(request.getIdentity(), request.getTransportActionsList());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/RemoteExtensionActionResponse.java b/server/src/main/java/org/opensearch/extensions/action/RemoteExtensionActionResponse.java
new file mode 100644
index 0000000000000..d092bee714941
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/RemoteExtensionActionResponse.java
@@ -0,0 +1,116 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * This class encapsulates the {@link ExtensionActionResponse} from an extension, adding a field denoting success
+ *
+ * @opensearch.internal
+ */
+public class RemoteExtensionActionResponse extends ActionResponse {
+    /**
+     * Indicates whether the response was successful. If false, responseBytes will include an error message.
+     */
+    private boolean success;
+    /**
+     * responseBytes is the raw bytes being transported between extensions.
+     */
+    private ExtensionActionResponse response;
+
+    /**
+     * RemoteExtensionActionResponse constructor.
+     *
+     * @param success Whether the response was successful.
+     * @param responseBytes is the raw bytes being transported between extensions.
+     */
+    public RemoteExtensionActionResponse(boolean success, byte[] responseBytes) {
+        this.success = success;
+        this.response = new ExtensionActionResponse(responseBytes);
+    }
+
+    /**
+     * RemoteExtensionActionResponse constructor from an {@link ExtensionActionResponse}.
+     *
+     * @param response an ExtensionActionResponse in which the first byte denotes success or failure
+     */
+    public RemoteExtensionActionResponse(ExtensionActionResponse response) {
+        byte[] combinedBytes = response.getResponseBytes();
+        this.success = combinedBytes[0] != 0;
+        byte[] responseBytes = new byte[combinedBytes.length - 1];
+        System.arraycopy(combinedBytes, 1, responseBytes, 0, responseBytes.length);
+        this.response = new ExtensionActionResponse(responseBytes);
+    }
+
+    /**
+     * RemoteExtensionActionResponse constructor from {@link StreamInput}.
+     *
+     * @param in bytes stream input used to de-serialize the message.
+     * @throws IOException when message de-serialization fails.
+     */
+    public RemoteExtensionActionResponse(StreamInput in) throws IOException {
+        this.success = in.readBoolean();
+        this.response = new ExtensionActionResponse(in);
+    }
+
+    public boolean isSuccess() {
+        return success;
+    }
+
+    public void setSuccess(boolean success) {
+        this.success = success;
+    }
+
+    public byte[] getResponseBytes() {
+        return response.getResponseBytes();
+    }
+
+    public void setResponseBytes(byte[] responseBytes) {
+        this.response = new ExtensionActionResponse(responseBytes);
+    }
+
+    /**
+     * Gets the Response bytes as a {@link StreamInput}
+     *
+     * @return A StreamInput representation of the response bytes
+     */
+    public StreamInput getResponseBytesAsStream() {
+        return StreamInput.wrap(response.getResponseBytes());
+    }
+
+    /**
+     * Gets the Response bytes as a UTF-8 string
+     *
+     * @return A string representation of the response bytes
+     */
+    public String getResponseBytesAsString() {
+        return new String(response.getResponseBytes(), StandardCharsets.UTF_8);
+    }
+
+    /**
+     * Sets the Response bytes from a UTF-8 string
+     *
+     * @param response The response to convert to bytes
+     */
+    public void setResponseBytesAsString(String response) {
+        this.response = new ExtensionActionResponse(response.getBytes(StandardCharsets.UTF_8));
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeBoolean(success);
+        response.writeTo(out);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/TransportActionRequestFromExtension.java b/server/src/main/java/org/opensearch/extensions/action/TransportActionRequestFromExtension.java
new file mode 100644
index 0000000000000..e0ce4488fff3e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/TransportActionRequestFromExtension.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionIdentityProto.ExtensionIdentity;
+import org.opensearch.extensions.proto.ExtensionTransportMessageProto.ExtensionTransportMessage;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Transport Action Request from Extension
+ *
+ * @opensearch.api
+ */
+public class TransportActionRequestFromExtension extends ActionRequest {
+    private final ExtensionIdentity identity;
+    private final ExtensionTransportMessage request;
+
+    /**
+     * TransportActionRequestFromExtension constructor.
+     *
+     * @param action is the transport action intended to be invoked which is registered by an extension via {@link ExtensionTransportActionsHandler}.
+     * @param requestBytes is the raw bytes being transported between extensions.
+     * @param uniqueId to identify which extension is making a transport request call.
+     */
+    public TransportActionRequestFromExtension(String action, ByteString requestBytes, String uniqueId) {
+        this.identity = ExtensionIdentity.newBuilder().setUniqueId(uniqueId).build();
+        this.request = ExtensionTransportMessage.newBuilder().setAction(action).setRequestBytes(requestBytes).build();
+    }
+
+    /**
+     * TransportActionRequestFromExtension constructor from {@link StreamInput}.
+     *
+     * @param in bytes stream input used to de-serialize the message.
+     * @throws IOException when message de-serialization fails.
+     */
+    public TransportActionRequestFromExtension(StreamInput in) throws IOException {
+        super(in);
+        this.identity = ExtensionIdentity.parseFrom(in.readByteArray());
+        this.request = ExtensionTransportMessage.parseFrom(in.readByteArray());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(identity.toByteArray());
+        out.writeByteArray(request.toByteArray());
+    }
+
+    public String getAction() {
+        return this.request.getAction();
+    }
+
+    public ByteString getRequestBytes() {
+        return this.request.getRequestBytes();
+    }
+
+    public String getUniqueId() {
+        return this.identity.getUniqueId();
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+
+    @Override
+    public String toString() {
+        return "TransportActionRequestFromExtension{action="
+            + request.getAction()
+            + ", requestBytes="
+            + request.getRequestBytes()
+            + ", uniqueId="
+            + identity.getUniqueId()
+            + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        TransportActionRequestFromExtension that = (TransportActionRequestFromExtension) obj;
+        return Objects.equals(request.getAction(), that.request.getAction())
+            && Objects.equals(request.getRequestBytes(), that.request.getRequestBytes())
+            && Objects.equals(identity.getUniqueId(), that.identity.getUniqueId());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(request.getAction(), request.getRequestBytes(), identity.getUniqueId());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/action/package-info.java b/server/src/main/java/org/opensearch/extensions/action/package-info.java
new file mode 100644
index 0000000000000..9bad08eaeb921
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/action/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Actions classes for the extensions package. OpenSearch extensions provide extensibility to OpenSearch.*/
+package org.opensearch.extensions.action;
diff --git a/server/src/main/java/org/opensearch/extensions/package-info.java b/server/src/main/java/org/opensearch/extensions/package-info.java
new file mode 100644
index 0000000000000..c6efd42499240
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Main OpenSearch extensions package. OpenSearch extensions provide extensibility to OpenSearch.*/
+package org.opensearch.extensions;
diff --git a/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java
new file mode 100644
index 0000000000000..65478e85081fa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java
@@ -0,0 +1,354 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.Version;
+import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Request to execute REST actions on extension node.
+ * This contains necessary portions of a {@link RestRequest} object, but does not pass the full request for security concerns.
+ *
+ * @opensearch.api
+ */
+public class ExtensionRestRequest extends TransportRequest {
+
+    private Method method;
+    private String uri;
+    private String path;
+    private Map<String, String> params;
+    private Map<String, List<String>> headers;
+    private MediaType mediaType = null;
+    private BytesReference content;
+    // The owner of this request object
+    // Will be replaced with PrincipalIdentifierToken class from feature/identity
+    private String principalIdentifierToken;
+    private HttpRequest.HttpVersion httpVersion;
+
+    // Tracks consumed parameters and content
+    private final Set<String> consumedParams = new HashSet<>();
+    private boolean contentConsumed = false;
+
+    /**
+     * This object can be instantiated given method, uri, params, content and identifier
+     *
+     * @param method              of type {@link Method}
+     * @param uri                 the REST uri string (excluding the query)
+     * @param path                the REST path
+     * @param params              the REST params
+     * @param headers             the REST headers
+     * @param mediaType           the content type, or null for plain text or no content
+     * @param content             the REST request content
+     * @param principalIdentifier the owner of this request
+     * @param httpVersion         the REST HTTP protocol version
+     */
+    public ExtensionRestRequest(
+        Method method,
+        String uri,
+        String path,
+        Map<String, String> params,
+        Map<String, List<String>> headers,
+        MediaType mediaType,
+        BytesReference content,
+        String principalIdentifier,
+        HttpRequest.HttpVersion httpVersion
+    ) {
+        this.method = method;
+        this.uri = uri;
+        this.path = path;
+        this.params = params;
+        this.headers = headers;
+        this.mediaType = mediaType;
+        this.content = content;
+        this.principalIdentifierToken = principalIdentifier;
+        this.httpVersion = httpVersion;
+    }
+
+    /**
+     * Instantiate this request from input stream
+     *
+     * @param in Input stream
+     * @throws IOException on failure to read the stream
+     */
+    public ExtensionRestRequest(StreamInput in) throws IOException {
+        super(in);
+        method = in.readEnum(RestRequest.Method.class);
+        uri = in.readString();
+        path = in.readString();
+        params = in.readMap(StreamInput::readString, StreamInput::readString);
+        headers = in.readMap(StreamInput::readString, StreamInput::readStringList);
+        if (in.readBoolean()) {
+            if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                mediaType = in.readMediaType();
+            } else {
+                mediaType = in.readEnum(XContentType.class);
+            }
+        }
+        content = in.readBytesReference();
+        principalIdentifierToken = in.readString();
+        httpVersion = in.readEnum(HttpRequest.HttpVersion.class);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeEnum(method);
+        out.writeString(uri);
+        out.writeString(path);
+        out.writeMap(params, StreamOutput::writeString, StreamOutput::writeString);
+        out.writeMap(headers, StreamOutput::writeString, StreamOutput::writeStringCollection);
+        out.writeBoolean(mediaType != null);
+        if (mediaType != null) {
+            if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                mediaType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) mediaType);
+            }
+        }
+        out.writeBytesReference(content);
+        out.writeString(principalIdentifierToken);
+        out.writeEnum(httpVersion);
+    }
+
+    /**
+     * Gets the REST method
+     *
+     * @return This REST request {@link Method} type
+     */
+    public Method method() {
+        return method;
+    }
+
+    /**
+     * Gets the REST uri
+     *
+     * @return This REST request's uri
+     */
+    public String uri() {
+        return uri;
+    }
+
+    /**
+     * Gets the REST path
+     *
+     * @return This REST request's path
+     */
+    public String path() {
+        return path;
+    }
+
+    /**
+     * Gets the full map of params without consuming them. Rest Handlers should use {@link #param(String)} or {@link #param(String, String)}
+     * to get parameter values.
+     *
+     * @return This REST request's params
+     */
+    public Map<String, String> params() {
+        return params;
+    }
+
+    /**
+     * Tests whether a parameter named {@code key} exists.
+     *
+     * @param key The parameter to test.
+     * @return True if there is a value for this parameter.
+     */
+    public boolean hasParam(String key) {
+        return params.containsKey(key);
+    }
+
+    /**
+     * Gets the value of a parameter, consuming it in the process.
+     *
+     * @param key The parameter key
+     * @return The parameter value if it exists, or null.
+     */
+    public String param(String key) {
+        consumedParams.add(key);
+        return params.get(key);
+    }
+
+    /**
+     * Gets the value of a parameter, consuming it in the process.
+     *
+     * @param key The parameter key
+     * @param defaultValue  A value to return if the parameter value doesn't exist.
+     * @return The parameter value if it exists, or the default value.
+     */
+    public String param(String key, String defaultValue) {
+        consumedParams.add(key);
+        return params.getOrDefault(key, defaultValue);
+    }
+
+    /**
+     * Gets the value of a parameter as a long, consuming it in the process.
+     *
+     * @param key The parameter key
+     * @param defaultValue A value to return if the parameter value doesn't exist.
+     * @return The parameter value if it exists, or the default value.
+     */
+    public long paramAsLong(String key, long defaultValue) {
+        String value = param(key);
+        if (value == null) {
+            return defaultValue;
+        }
+        try {
+            return Long.parseLong(value);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("Unable to parse param '" + key + "' value '" + value + "' to a long.", e);
+        }
+    }
+
+    /**
+     * Returns parameters consumed by {@link #param(String)} or {@link #param(String, String)}.
+     *
+     * @return a list of consumed parameters.
+     */
+    public List<String> consumedParams() {
+        return new ArrayList<>(consumedParams);
+    }
+
+    /**
+     * Gets the headers of request
+     * @return a map of request headers
+     */
+    public Map<String, List<String>> headers() {
+        return headers;
+    }
+
+    /**
+     * Gets the content type, if any.
+     *
+     * @return the content type of the {@link #content()}, or null if the context is plain text or if there is no content.
+     */
+    public MediaType getXContentType() {
+        return mediaType;
+    }
+
+    /**
+     * Gets the content.
+     *
+     * @return This REST request's content
+     */
+    public BytesReference content() {
+        contentConsumed = true;
+        return content;
+    }
+
+    /**
+     * Tests whether content exists.
+     *
+     * @return True if there is non-empty content.
+     */
+    public boolean hasContent() {
+        return content.length() > 0;
+    }
+
+    /**
+     * Tests whether content has been consumed.
+     *
+     * @return True if the content was consumed.
+     */
+    public boolean isContentConsumed() {
+        return contentConsumed;
+    }
+
+    /**
+     * Gets a parser for the contents of this request if there is content and an xContentType.
+     *
+     * @param xContentRegistry The extension's xContentRegistry
+     * @return A parser for the given content and content type.
+     * @throws OpenSearchParseException on missing body or xContentType.
+     * @throws IOException on a failure creating the parser.
+     */
+    public final XContentParser contentParser(NamedXContentRegistry xContentRegistry) throws IOException {
+        if (!hasContent() || getXContentType() == null) {
+            throw new OpenSearchParseException("There is no request body or the ContentType is invalid.");
+        }
+        return getXContentType().xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, content.streamInput());
+    }
+
+    /**
+     * @return This REST request issuer's identity token
+     */
+    public String getRequestIssuerIdentity() {
+        return principalIdentifierToken;
+    }
+
+    /**
+     * @return This REST request's HTTP protocol version
+     */
+    public HttpRequest.HttpVersion protocolVersion() {
+        return httpVersion;
+    }
+
+    @Override
+    public String toString() {
+        return "ExtensionRestRequest{method="
+            + method
+            + ", uri="
+            + uri
+            + ", path="
+            + path
+            + ", params="
+            + params
+            + ", headers="
+            + headers.toString()
+            + ", xContentType="
+            + mediaType
+            + ", contentLength="
+            + content.length()
+            + ", requester="
+            + principalIdentifierToken
+            + ", httpVersion="
+            + httpVersion
+            + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        ExtensionRestRequest that = (ExtensionRestRequest) obj;
+        return Objects.equals(method, that.method)
+            && Objects.equals(uri, that.uri)
+            && Objects.equals(path, that.path)
+            && Objects.equals(params, that.params)
+            && Objects.equals(headers, that.headers)
+            && Objects.equals(mediaType, that.mediaType)
+            && Objects.equals(content, that.content)
+            && Objects.equals(principalIdentifierToken, that.principalIdentifierToken)
+            && Objects.equals(httpVersion, that.httpVersion);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(method, uri, path, params, headers, mediaType, content, principalIdentifierToken, httpVersion);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestResponse.java b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestResponse.java
new file mode 100644
index 0000000000000..af539d864a4d6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestResponse.java
@@ -0,0 +1,114 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.RestRequest;
+
+import java.util.List;
+
+/**
+ * A subclass of {@link BytesRestResponse} which also tracks consumed parameters and content.
+ *
+ * @opensearch.api
+ */
+public class ExtensionRestResponse extends BytesRestResponse {
+
+    private final List<String> consumedParams;
+    private final boolean contentConsumed;
+
+    /**
+     * Creates a new response based on {@link XContentBuilder}.
+     *
+     * @param request  the REST request being responded to.
+     * @param status  The REST status.
+     * @param builder  The builder for the response.
+     */
+    public ExtensionRestResponse(RestRequest request, RestStatus status, XContentBuilder builder) {
+        super(status, builder);
+        this.consumedParams = request.consumedParams();
+        this.contentConsumed = request.isContentConsumed();
+    }
+
+    /**
+     * Creates a new plain text response.
+     *
+     * @param request  the REST request being responded to.
+     * @param status  The REST status.
+     * @param content  A plain text response string.
+     */
+    public ExtensionRestResponse(RestRequest request, RestStatus status, String content) {
+        super(status, content);
+        this.consumedParams = request.consumedParams();
+        this.contentConsumed = request.isContentConsumed();
+    }
+
+    /**
+     * Creates a new plain text response.
+     *
+     * @param request  the REST request being responded to.
+     * @param status  The REST status.
+     * @param contentType  The content type of the response string.
+     * @param content  A response string.
+     */
+    public ExtensionRestResponse(RestRequest request, RestStatus status, String contentType, String content) {
+        super(status, contentType, content);
+        this.consumedParams = request.consumedParams();
+        this.contentConsumed = request.isContentConsumed();
+    }
+
+    /**
+     * Creates a binary response.
+     *
+     * @param request  the REST request being responded to.
+     * @param status  The REST status.
+     * @param contentType  The content type of the response bytes.
+     * @param content  Response bytes.
+     */
+    public ExtensionRestResponse(RestRequest request, RestStatus status, String contentType, byte[] content) {
+        super(status, contentType, content);
+        this.consumedParams = request.consumedParams();
+        this.contentConsumed = request.isContentConsumed();
+    }
+
+    /**
+     * Creates a binary response.
+     *
+     * @param request  the REST request being responded to.
+     * @param status  The REST status.
+     * @param contentType  The content type of the response bytes.
+     * @param content  Response bytes.
+     */
+    public ExtensionRestResponse(RestRequest request, RestStatus status, String contentType, BytesReference content) {
+        super(status, contentType, content);
+        this.consumedParams = request.consumedParams();
+        this.contentConsumed = request.isContentConsumed();
+    }
+
+    /**
+     * Gets the list of consumed parameters. These are needed to consume the parameters of the original request.
+     *
+     * @return the list of consumed params.
+     */
+    public List<String> getConsumedParams() {
+        return consumedParams;
+    }
+
+    /**
+     * Reports whether content was consumed.
+     *
+     * @return true if the content was consumed, false otherwise.
+     */
+    public boolean isContentConsumed() {
+        return contentConsumed;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RegisterRestActionsRequest.java b/server/src/main/java/org/opensearch/extensions/rest/RegisterRestActionsRequest.java
new file mode 100644
index 0000000000000..3453375969b5c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/RegisterRestActionsRequest.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.ExtensionIdentityProto.ExtensionIdentity;
+import org.opensearch.extensions.proto.RegisterRestActionsProto.RegisterRestActions;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Request to register extension REST actions
+ *
+ * @opensearch.internal
+ */
+public class RegisterRestActionsRequest extends TransportRequest {
+    private final RegisterRestActions request;
+
+    public RegisterRestActionsRequest(String uniqueId, List<String> restActions, List<String> deprecatedRestActions) {
+        ExtensionIdentity identity = ExtensionIdentity.newBuilder().setUniqueId(uniqueId).build();
+        this.request = RegisterRestActions.newBuilder()
+            .setIdentity(identity)
+            .addAllRestActions(restActions)
+            .addAllDeprecatedRestActions(deprecatedRestActions)
+            .build();
+    }
+
+    public RegisterRestActionsRequest(StreamInput in) throws IOException {
+        super(in);
+        request = RegisterRestActions.parseFrom(in.readByteArray());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeByteArray(request.toByteArray());
+    }
+
+    public String getUniqueId() {
+        return request.getIdentity().getUniqueId();
+    }
+
+    public List<String> getRestActions() {
+        return List.copyOf(request.getRestActionsList());
+    }
+
+    public List<String> getDeprecatedRestActions() {
+        return List.copyOf(request.getDeprecatedRestActionsList());
+    }
+
+    @Override
+    public String toString() {
+        return "RestActionsRequest{Identity="
+            + request.getIdentity()
+            + ", restActions="
+            + request.getRestActionsList()
+            + ", deprecatedRestActions="
+            + request.getDeprecatedRestActionsList()
+            + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        RegisterRestActionsRequest that = (RegisterRestActionsRequest) obj;
+        return Objects.equals(request.getIdentity().getUniqueId(), that.request.getIdentity().getUniqueId())
+            && Objects.equals(request.getRestActionsList(), that.request.getRestActionsList())
+            && Objects.equals(request.getDeprecatedRestActionsList(), that.request.getDeprecatedRestActionsList());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(request.getIdentity(), request.getRestActionsList(), request.getDeprecatedRestActionsList());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RestActionsRequestHandler.java b/server/src/main/java/org/opensearch/extensions/rest/RestActionsRequestHandler.java
new file mode 100644
index 0000000000000..18adc37156ca1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/RestActionsRequestHandler.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.extensions.AcknowledgedResponse;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.rest.RestController;
+import org.opensearch.rest.RestHandler;
+import org.opensearch.transport.TransportService;
+
+import java.util.Map;
+
+/**
+ * Handles requests to register extension REST actions.
+ *
+ * @opensearch.internal
+ */
+public class RestActionsRequestHandler {
+
+    private final RestController restController;
+    private final Map<String, DiscoveryExtensionNode> extensionIdMap;
+    private final TransportService transportService;
+
+    /**
+     * Instantiates a new REST Actions Request Handler using the Node's RestController.
+     *
+     * @param restController  The Node's {@link RestController}.
+     * @param extensionIdMap  A map of extension uniqueId to DiscoveryExtensionNode
+     * @param transportService  The Node's transportService
+     */
+    public RestActionsRequestHandler(
+        RestController restController,
+        Map<String, DiscoveryExtensionNode> extensionIdMap,
+        TransportService transportService
+    ) {
+        this.restController = restController;
+        this.extensionIdMap = extensionIdMap;
+        this.transportService = transportService;
+    }
+
+    /**
+     * Handles a {@link RegisterRestActionsRequest}.
+     *
+     * @param restActionsRequest  The request to handle.
+     * @return A {@link AcknowledgedResponse} indicating success.
+     * @throws Exception if the request is not handled properly.
+     */
+    public TransportResponse handleRegisterRestActionsRequest(
+        RegisterRestActionsRequest restActionsRequest,
+        DynamicActionRegistry dynamicActionRegistry
+    ) throws Exception {
+        DiscoveryExtensionNode discoveryExtensionNode = extensionIdMap.get(restActionsRequest.getUniqueId());
+        if (discoveryExtensionNode == null) {
+            throw new IllegalStateException("Missing extension node for " + restActionsRequest.getUniqueId());
+        }
+        RestHandler handler = new RestSendToExtensionAction(
+            restActionsRequest,
+            discoveryExtensionNode,
+            transportService,
+            dynamicActionRegistry
+        );
+        restController.registerHandler(handler);
+        return new AcknowledgedResponse(true);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RestExecuteOnExtensionResponse.java b/server/src/main/java/org/opensearch/extensions/rest/RestExecuteOnExtensionResponse.java
new file mode 100644
index 0000000000000..9cddca6c0e14d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/RestExecuteOnExtensionResponse.java
@@ -0,0 +1,134 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.rest.RestResponse;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Response to execute REST Actions on the extension node. Wraps the components of a {@link RestResponse}.
+ *
+ * @opensearch.internal
+ */
+public class RestExecuteOnExtensionResponse extends TransportResponse {
+
+    private RestStatus status;
+    private String contentType;
+    private byte[] content;
+    private Map<String, List<String>> headers;
+    private List<String> consumedParams;
+    private boolean contentConsumed;
+
+    /**
+     * Instantiate this object with the components of a {@link RestResponse}.
+     *
+     * @param status  The REST status.
+     * @param contentType  The type of the content.
+     * @param content  The content.
+     * @param headers  The headers.
+     * @param consumedParams  The consumed params.
+     * @param contentConsumed  Whether content was consumed.
+     */
+    public RestExecuteOnExtensionResponse(
+        RestStatus status,
+        String contentType,
+        byte[] content,
+        Map<String, List<String>> headers,
+        List<String> consumedParams,
+        boolean contentConsumed
+    ) {
+        super();
+        setStatus(status);
+        setContentType(contentType);
+        setContent(content);
+        setHeaders(headers);
+        setConsumedParams(consumedParams);
+        setContentConsumed(contentConsumed);
+    }
+
+    /**
+     * Instantiate this object from a Transport Stream.
+     *
+     * @param in  The stream input.
+     * @throws IOException on transport failure.
+     */
+    public RestExecuteOnExtensionResponse(StreamInput in) throws IOException {
+        setStatus(in.readEnum(RestStatus.class));
+        setContentType(in.readString());
+        setContent(in.readByteArray());
+        setHeaders(in.readMapOfLists(StreamInput::readString, StreamInput::readString));
+        setConsumedParams(in.readStringList());
+        setContentConsumed(in.readBoolean());
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeEnum(status);
+        out.writeString(contentType);
+        out.writeByteArray(content);
+        out.writeMapOfLists(headers, StreamOutput::writeString, StreamOutput::writeString);
+        out.writeStringCollection(consumedParams);
+        out.writeBoolean(contentConsumed);
+    }
+
+    public RestStatus getStatus() {
+        return status;
+    }
+
+    public void setStatus(RestStatus status) {
+        this.status = status;
+    }
+
+    public String getContentType() {
+        return contentType;
+    }
+
+    public void setContentType(String contentType) {
+        this.contentType = contentType;
+    }
+
+    public byte[] getContent() {
+        return content;
+    }
+
+    public void setContent(byte[] content) {
+        this.content = content;
+    }
+
+    public Map<String, List<String>> getHeaders() {
+        return headers;
+    }
+
+    public void setHeaders(Map<String, List<String>> headers) {
+        this.headers = Map.copyOf(headers);
+    }
+
+    public List<String> getConsumedParams() {
+        return consumedParams;
+    }
+
+    public void setConsumedParams(List<String> consumedParams) {
+        this.consumedParams = consumedParams;
+    }
+
+    public boolean isContentConsumed() {
+        return contentConsumed;
+    }
+
+    public void setContentConsumed(boolean contentConsumed) {
+        this.contentConsumed = contentConsumed;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RestInitializeExtensionAction.java b/server/src/main/java/org/opensearch/extensions/rest/RestInitializeExtensionAction.java
new file mode 100644
index 0000000000000..fc7c21a6eccd6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/RestInitializeExtensionAction.java
@@ -0,0 +1,191 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.Version;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.extensions.ExtensionDependency;
+import org.opensearch.extensions.ExtensionScopedSettings;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.extensions.ExtensionsSettings.Extension;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.NamedRoute;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.transport.ConnectTransportException;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.TimeoutException;
+import java.util.stream.Collectors;
+
+import static org.opensearch.rest.RestRequest.Method.POST;
+
+/**
+ * An action that initializes an extension
+ */
+public class RestInitializeExtensionAction extends BaseRestHandler {
+
+    private final ExtensionsManager extensionsManager;
+
+    @Override
+    public String getName() {
+        return ExtensionsManager.REQUEST_EXTENSION_ACTION_NAME;
+    }
+
+    @Override
+    public List<Route> routes() {
+        return List.of(new NamedRoute.Builder().method(POST).path("/_extensions/initialize").uniqueName("extensions:initialize").build());
+    }
+
+    public RestInitializeExtensionAction(ExtensionsManager extensionsManager) {
+        this.extensionsManager = extensionsManager;
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        String name = null;
+        String uniqueId = null;
+        String hostAddress = null;
+        String port = null;
+        String version = null;
+        String openSearchVersion = null;
+        String minimumCompatibleVersion = null;
+        List<ExtensionDependency> dependencies = new ArrayList<>();
+        Set<String> additionalSettingsKeys = extensionsManager.getAdditionalSettings()
+            .stream()
+            .map(s -> s.getKey())
+            .collect(Collectors.toSet());
+
+        Tuple<? extends MediaType, Map<String, Object>> unreadExtensionTuple = XContentHelper.convertToMap(
+            request.content(),
+            false,
+            request.getMediaType().xContent().mediaType()
+        );
+        Map<String, Object> extensionMap = unreadExtensionTuple.v2();
+
+        ExtensionScopedSettings extAdditionalSettings = new ExtensionScopedSettings(extensionsManager.getAdditionalSettings());
+
+        try {
+            // checking to see whether any required fields are missing from extension initialization request or not
+            String[] requiredFields = {
+                "name",
+                "uniqueId",
+                "hostAddress",
+                "port",
+                "version",
+                "opensearchVersion",
+                "minimumCompatibleVersion" };
+            List<String> missingFields = Arrays.stream(requiredFields)
+                .filter(field -> !extensionMap.containsKey(field))
+                .collect(Collectors.toList());
+            if (!missingFields.isEmpty()) {
+                throw new IOException("Extension is missing these required fields : " + missingFields);
+            }
+
+            // Parse extension dependencies
+            List<ExtensionDependency> extensionDependencyList = new ArrayList<ExtensionDependency>();
+            if (extensionMap.get("dependencies") != null) {
+                List<HashMap<String, ?>> extensionDependencies = new ArrayList<>(
+                    (Collection<HashMap<String, ?>>) extensionMap.get("dependencies")
+                );
+                for (HashMap<String, ?> dependency : extensionDependencies) {
+                    if (Strings.isNullOrEmpty((String) dependency.get("uniqueId"))) {
+                        throw new IOException("Required field [uniqueId] is missing in the request for the dependent extension");
+                    } else if (dependency.get("version") == null) {
+                        throw new IOException("Required field [version] is missing in the request for the dependent extension");
+                    }
+                    extensionDependencyList.add(
+                        new ExtensionDependency(
+                            dependency.get("uniqueId").toString(),
+                            Version.fromString(dependency.get("version").toString())
+                        )
+                    );
+                }
+            }
+
+            Map<String, ?> additionalSettingsMap = extensionMap.entrySet()
+                .stream()
+                .filter(kv -> additionalSettingsKeys.contains(kv.getKey()))
+                .collect(Collectors.toMap(map -> map.getKey(), map -> map.getValue()));
+
+            Settings.Builder output = Settings.builder();
+            output.loadFromMap(additionalSettingsMap);
+            extAdditionalSettings.applySettings(output.build());
+
+            // Create extension read from initialization request
+            name = extensionMap.get("name").toString();
+            uniqueId = extensionMap.get("uniqueId").toString();
+            hostAddress = extensionMap.get("hostAddress").toString();
+            port = extensionMap.get("port").toString();
+            version = extensionMap.get("version").toString();
+            openSearchVersion = extensionMap.get("opensearchVersion").toString();
+            minimumCompatibleVersion = extensionMap.get("minimumCompatibleVersion").toString();
+            dependencies = extensionDependencyList;
+        } catch (IOException e) {
+            logger.warn("loading extension has been failed because of exception : " + e.getMessage());
+            return channel -> channel.sendResponse(new BytesRestResponse(RestStatus.INTERNAL_SERVER_ERROR, e.getMessage()));
+        }
+
+        Extension extension = new Extension(
+            name,
+            uniqueId,
+            hostAddress,
+            port,
+            version,
+            openSearchVersion,
+            minimumCompatibleVersion,
+            dependencies,
+            extAdditionalSettings
+        );
+        try {
+            extensionsManager.initializeExtension(extension);
+        } catch (CompletionException e) {
+            Throwable cause = e.getCause();
+            if (cause instanceof TimeoutException) {
+                return channel -> channel.sendResponse(
+                    new BytesRestResponse(RestStatus.REQUEST_TIMEOUT, "No response from extension to request.")
+                );
+            } else if (cause instanceof ConnectTransportException || cause instanceof RuntimeException) {
+                return channel -> channel.sendResponse(
+                    new BytesRestResponse(RestStatus.REQUEST_TIMEOUT, "Connection failed with the extension.")
+                );
+            }
+            if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            }
+        } catch (Exception e) {
+            return channel -> channel.sendResponse(new BytesRestResponse(RestStatus.INTERNAL_SERVER_ERROR, e.getMessage()));
+
+        }
+
+        return channel -> {
+            try (XContentBuilder builder = channel.newBuilder()) {
+                builder.startObject();
+                builder.field("success", "A request to initialize an extension has been sent.");
+                builder.endObject();
+                channel.sendResponse(new BytesRestResponse(RestStatus.ACCEPTED, builder));
+            }
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java b/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java
new file mode 100644
index 0000000000000..cb84d36380c3c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java
@@ -0,0 +1,298 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.NamedRoute;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.security.Principal;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.unmodifiableList;
+
+/**
+ * An action that forwards REST requests to an extension
+ */
+public class RestSendToExtensionAction extends BaseRestHandler {
+
+    private static final String SEND_TO_EXTENSION_ACTION = "send_to_extension_action";
+    private static final Logger logger = LogManager.getLogger(RestSendToExtensionAction.class);
+    // To replace with user identity see https://github.com/opensearch-project/OpenSearch/pull/4247
+    private static final Principal DEFAULT_PRINCIPAL = new Principal() {
+        @Override
+        public String getName() {
+            return "OpenSearchUser";
+        }
+    };
+
+    private final List<Route> routes;
+    private final List<DeprecatedRoute> deprecatedRoutes;
+    private final String pathPrefix;
+    private final DiscoveryExtensionNode discoveryExtensionNode;
+    private final TransportService transportService;
+
+    private static final Set<String> allowList = Set.of("Content-Type");
+    private static final Set<String> denyList = Set.of("Authorization", "Proxy-Authorization");
+
+    /**
+     * Instantiates this object using a {@link RegisterRestActionsRequest} to populate the routes.
+     *
+     * @param restActionsRequest A request encapsulating a list of Strings with the API methods and paths.
+     * @param transportService The OpenSearch transport service
+     * @param discoveryExtensionNode The extension node to which to send actions
+     */
+    public RestSendToExtensionAction(
+        RegisterRestActionsRequest restActionsRequest,
+        DiscoveryExtensionNode discoveryExtensionNode,
+        TransportService transportService,
+        DynamicActionRegistry dynamicActionRegistry
+    ) {
+        this.pathPrefix = "/_extensions/_" + restActionsRequest.getUniqueId();
+        RestRequest.Method method;
+        String path;
+
+        List<Route> restActionsAsRoutes = new ArrayList<>();
+        for (String restAction : restActionsRequest.getRestActions()) {
+
+            // TODO Find a better way to parse these to avoid code-smells
+
+            String name;
+            Set<String> actionNames = new HashSet<>();
+            String[] parts = restAction.split(" ");
+            if (parts.length < 3) {
+                throw new IllegalArgumentException("REST action must contain at least a REST method, a route and a unique name");
+            }
+            try {
+                method = RestRequest.Method.valueOf(parts[0].trim());
+                path = pathPrefix + parts[1].trim();
+                name = parts[2].trim();
+
+                // comma-separated action names
+                if (parts.length > 3) {
+                    String[] actions = parts[3].split(",");
+                    for (String action : actions) {
+                        String trimmed = action.trim();
+                        if (!trimmed.isEmpty()) {
+                            actionNames.add(trimmed);
+                        }
+                    }
+                }
+            } catch (IndexOutOfBoundsException | IllegalArgumentException e) {
+                throw new IllegalArgumentException(restAction + " does not begin with a valid REST method");
+            }
+            logger.info("Registering: " + method + " " + path + " " + name);
+
+            // All extension routes being registered must have a unique name associated with them
+            NamedRoute nr = new NamedRoute.Builder().method(method).path(path).uniqueName(name).legacyActionNames(actionNames).build();
+            restActionsAsRoutes.add(nr);
+            dynamicActionRegistry.registerDynamicRoute(nr, this);
+        }
+        this.routes = unmodifiableList(restActionsAsRoutes);
+
+        // TODO: Modify {@link NamedRoute} to support deprecated route registration
+        List<DeprecatedRoute> restActionsAsDeprecatedRoutes = new ArrayList<>();
+        // Iterate in pairs of route / deprecation message
+        List<String> deprecatedActions = restActionsRequest.getDeprecatedRestActions();
+        for (int i = 0; i < deprecatedActions.size() - 1; i += 2) {
+            String restAction = deprecatedActions.get(i);
+            String message = deprecatedActions.get(i + 1);
+            int delim = restAction.indexOf(' ');
+            try {
+                method = RestRequest.Method.valueOf(restAction.substring(0, delim));
+                path = pathPrefix + restAction.substring(delim).trim();
+            } catch (IndexOutOfBoundsException | IllegalArgumentException e) {
+                throw new IllegalArgumentException(restAction + " does not begin with a valid REST method");
+            }
+            logger.info("Registering: " + method + " " + path + " with deprecation message " + message);
+            restActionsAsDeprecatedRoutes.add(new DeprecatedRoute(method, path, message));
+        }
+        this.deprecatedRoutes = unmodifiableList(restActionsAsDeprecatedRoutes);
+
+        this.discoveryExtensionNode = discoveryExtensionNode;
+        this.transportService = transportService;
+    }
+
+    @Override
+    public String getName() {
+        return this.discoveryExtensionNode.getId() + ":" + SEND_TO_EXTENSION_ACTION;
+    }
+
+    @Override
+    public List<Route> routes() {
+        return this.routes;
+    }
+
+    @Override
+    public List<DeprecatedRoute> deprecatedRoutes() {
+        return this.deprecatedRoutes;
+    }
+
+    public Map<String, List<String>> filterHeaders(Map<String, List<String>> headers, Set<String> allowList, Set<String> denyList) {
+        Map<String, List<String>> filteredHeaders = headers.entrySet()
+            .stream()
+            .filter(e -> !denyList.contains(e.getKey()))
+            .filter(e -> allowList.contains(e.getKey()))
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        return filteredHeaders;
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
+        HttpRequest httpRequest = request.getHttpRequest();
+        String path = request.path();
+        Method method = request.method();
+        String uri = httpRequest.uri();
+        Map<String, String> params = request.params();
+        Map<String, List<String>> headers = request.getHeaders();
+        MediaType contentType = request.getMediaType();
+        BytesReference content = request.content();
+        HttpRequest.HttpVersion httpVersion = httpRequest.protocolVersion();
+
+        if (path.startsWith(pathPrefix)) {
+            path = path.substring(pathPrefix.length());
+        }
+        String message = "Forwarding the request " + method + " " + path + " to " + discoveryExtensionNode;
+        logger.info(message);
+        // Initialize response. Values will be changed in the handler.
+        final RestExecuteOnExtensionResponse restExecuteOnExtensionResponse = new RestExecuteOnExtensionResponse(
+            RestStatus.INTERNAL_SERVER_ERROR,
+            BytesRestResponse.TEXT_CONTENT_TYPE,
+            message.getBytes(StandardCharsets.UTF_8),
+            emptyMap(),
+            emptyList(),
+            false
+        );
+        final CompletableFuture<RestExecuteOnExtensionResponse> inProgressFuture = new CompletableFuture<>();
+        final TransportResponseHandler<RestExecuteOnExtensionResponse> restExecuteOnExtensionResponseHandler = new TransportResponseHandler<
+            RestExecuteOnExtensionResponse>() {
+
+            @Override
+            public RestExecuteOnExtensionResponse read(StreamInput in) throws IOException {
+                return new RestExecuteOnExtensionResponse(in);
+            }
+
+            @Override
+            public void handleResponse(RestExecuteOnExtensionResponse response) {
+                logger.info("Received response from extension: {}", response.getStatus());
+                restExecuteOnExtensionResponse.setStatus(response.getStatus());
+                restExecuteOnExtensionResponse.setContentType(response.getContentType());
+                restExecuteOnExtensionResponse.setContent(response.getContent());
+                restExecuteOnExtensionResponse.setHeaders(response.getHeaders());
+                // Consume parameters and content
+                response.getConsumedParams().stream().forEach(p -> request.param(p));
+                if (response.isContentConsumed()) {
+                    request.content();
+                }
+                inProgressFuture.complete(response);
+            }
+
+            @Override
+            public void handleException(TransportException exp) {
+                logger.debug("REST request failed", exp);
+                // On failure the original request params and content aren't consumed
+                // which gives misleading error messages, so we just consume them here
+                request.params().keySet().stream().forEach(p -> request.param(p));
+                request.content();
+                inProgressFuture.completeExceptionally(exp);
+            }
+
+            @Override
+            public String executor() {
+                return ThreadPool.Names.GENERIC;
+            }
+        };
+
+        try {
+            // Will be replaced with ExtensionTokenProcessor and PrincipalIdentifierToken classes from feature/identity
+            final String extensionTokenProcessor = "placeholder_token_processor";
+            final String requestIssuerIdentity = "placeholder_request_issuer_identity";
+
+            Map<String, List<String>> filteredHeaders = filterHeaders(headers, allowList, denyList);
+
+            transportService.sendRequest(
+                discoveryExtensionNode,
+                ExtensionsManager.REQUEST_REST_EXECUTE_ON_EXTENSION_ACTION,
+                // DO NOT INCLUDE HEADERS WITH SECURITY OR PRIVACY INFORMATION
+                // SEE https://github.com/opensearch-project/OpenSearch/issues/4429
+                new ExtensionRestRequest(
+                    method,
+                    uri,
+                    path,
+                    params,
+                    filteredHeaders,
+                    contentType,
+                    content,
+                    requestIssuerIdentity,
+                    httpVersion
+                ),
+                restExecuteOnExtensionResponseHandler
+            );
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            Throwable cause = e.getCause();
+            if (cause instanceof TimeoutException) {
+                return channel -> channel.sendResponse(
+                    new BytesRestResponse(RestStatus.REQUEST_TIMEOUT, "No response from extension to request.")
+                );
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        } catch (Exception ex) {
+            logger.info("Failed to send REST Actions to extension " + discoveryExtensionNode.getName(), ex);
+            return channel -> channel.sendResponse(new BytesRestResponse(RestStatus.INTERNAL_SERVER_ERROR, ex.getMessage()));
+        }
+        BytesRestResponse restResponse = new BytesRestResponse(
+            restExecuteOnExtensionResponse.getStatus(),
+            restExecuteOnExtensionResponse.getContentType(),
+            restExecuteOnExtensionResponse.getContent()
+        );
+        // No constructor that includes headers so we roll our own
+        restExecuteOnExtensionResponse.getHeaders().entrySet().stream().forEach(e -> {
+            e.getValue().stream().forEach(v -> restResponse.addHeader(e.getKey(), v));
+        });
+
+        return channel -> channel.sendResponse(restResponse);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/rest/package-info.java b/server/src/main/java/org/opensearch/extensions/rest/package-info.java
new file mode 100644
index 0000000000000..5a52a295da6ad
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/rest/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** REST Actions classes for the extensions package. OpenSearch extensions provide extensibility to OpenSearch.*/
+package org.opensearch.extensions.rest;
diff --git a/server/src/main/java/org/opensearch/extensions/settings/CustomSettingsRequestHandler.java b/server/src/main/java/org/opensearch/extensions/settings/CustomSettingsRequestHandler.java
new file mode 100644
index 0000000000000..562fdad54abe4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/settings/CustomSettingsRequestHandler.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.settings;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.SettingsModule;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.extensions.AcknowledgedResponse;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Handles requests to register a list of custom extension settings.
+ *
+ * @opensearch.internal
+ */
+public class CustomSettingsRequestHandler {
+
+    private final SettingsModule settingsModule;
+
+    /**
+     * Instantiates a new Settings Request Handler using the Node's SettingsModule.
+     *
+     * @param settingsModule  The Node's {@link SettingsModule}.
+     */
+    public CustomSettingsRequestHandler(SettingsModule settingsModule) {
+        this.settingsModule = settingsModule;
+    }
+
+    /**
+     * Handles a {@link RegisterCustomSettingsRequest}.
+     *
+     * @param customSettingsRequest  The request to handle.
+     * @return A {@link AcknowledgedResponse} indicating success.
+     * @throws Exception if the request is not handled properly.
+     */
+    public TransportResponse handleRegisterCustomSettingsRequest(RegisterCustomSettingsRequest customSettingsRequest) throws Exception {
+        // TODO: How do we prevent key collisions in settings registration?
+        // we have settingsRequest.getUniqueId() available or could enforce reverse DNS naming
+        // See https://github.com/opensearch-project/opensearch-sdk-java/issues/142
+        List<String> registeredCustomSettings = new ArrayList<>();
+        for (Setting<?> setting : customSettingsRequest.getSettings()) {
+            settingsModule.registerDynamicSetting(setting);
+            registeredCustomSettings.add(setting.getKey());
+        }
+        return new AcknowledgedResponse(true);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/settings/RegisterCustomSettingsRequest.java b/server/src/main/java/org/opensearch/extensions/settings/RegisterCustomSettingsRequest.java
new file mode 100644
index 0000000000000..1145d4bc69d2c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/settings/RegisterCustomSettingsRequest.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.settings;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.WriteableSetting;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Request to register a list of custom extension settings
+ *
+ * @opensearch.internal
+ */
+public class RegisterCustomSettingsRequest extends TransportRequest {
+    private String uniqueId;
+    private List<Setting<?>> settings;
+
+    public RegisterCustomSettingsRequest(String uniqueId, List<Setting<?>> settings) {
+        this.uniqueId = uniqueId;
+        this.settings = new ArrayList<>(settings);
+    }
+
+    public RegisterCustomSettingsRequest(StreamInput in) throws IOException {
+        super(in);
+        this.uniqueId = in.readString();
+        int size = in.readVInt();
+        this.settings = new ArrayList<>(size);
+        for (int i = 0; i < size; i++) {
+            WriteableSetting ws = new WriteableSetting(in);
+            this.settings.add(ws.getSetting());
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeString(uniqueId);
+        out.writeVInt(settings.size());
+        for (Setting<?> setting : settings) {
+            new WriteableSetting(setting).writeTo(out);
+        }
+    }
+
+    public String getUniqueId() {
+        return uniqueId;
+    }
+
+    public List<Setting<?>> getSettings() {
+        return new ArrayList<>(settings);
+    }
+
+    @Override
+    public String toString() {
+        return "RegisterSettingsRequest{uniqueId=" + uniqueId + ", settings=" + settings + "}";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        RegisterCustomSettingsRequest that = (RegisterCustomSettingsRequest) obj;
+        return Objects.equals(uniqueId, that.uniqueId) && Objects.equals(settings, that.settings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(uniqueId, settings);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/extensions/settings/package-info.java b/server/src/main/java/org/opensearch/extensions/settings/package-info.java
new file mode 100644
index 0000000000000..4ae82baba9bbb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/extensions/settings/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Settings classes for the extensions package. OpenSearch extensions provide extensibility to OpenSearch.*/
+package org.opensearch.extensions.settings;
diff --git a/server/src/main/java/org/opensearch/gateway/AsyncShardFetch.java b/server/src/main/java/org/opensearch/gateway/AsyncShardFetch.java
index e3c840b5d896e..d0ade4eb25168 100644
--- a/server/src/main/java/org/opensearch/gateway/AsyncShardFetch.java
+++ b/server/src/main/java/org/opensearch/gateway/AsyncShardFetch.java
@@ -31,12 +31,10 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
@@ -45,8 +43,9 @@
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.lease.Releasable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.ReceiveTimeoutTransportException;
 
 import java.util.ArrayList;
@@ -69,6 +68,8 @@
  * The async fetch logic maintains a map of which nodes are being fetched from in an async manner,
  * and once the results are back, it makes sure to schedule a reroute to make sure those results will
  * be taken into account.
+ *
+ * @opensearch.internal
  */
 public abstract class AsyncShardFetch<T extends BaseNodeResponse> implements Releasable {
 
@@ -293,8 +294,7 @@ synchronized void clearCacheForNode(String nodeId) {
      */
     private void fillShardCacheWithDataNodes(Map<String, NodeEntry<T>> shardCache, DiscoveryNodes nodes) {
         // verify that all current data nodes are there
-        for (ObjectObjectCursor<String, DiscoveryNode> cursor : nodes.getDataNodes()) {
-            DiscoveryNode node = cursor.value;
+        for (final DiscoveryNode node : nodes.getDataNodes().values()) {
             if (shardCache.containsKey(node.getId()) == false) {
                 shardCache.put(node.getId(), new NodeEntry<T>(node.getId()));
             }
diff --git a/server/src/main/java/org/opensearch/gateway/BaseGatewayShardAllocator.java b/server/src/main/java/org/opensearch/gateway/BaseGatewayShardAllocator.java
index bbc78d78f4636..59ef894958cbe 100644
--- a/server/src/main/java/org/opensearch/gateway/BaseGatewayShardAllocator.java
+++ b/server/src/main/java/org/opensearch/gateway/BaseGatewayShardAllocator.java
@@ -53,6 +53,8 @@
  *
  * Individual implementations of this class are responsible for providing
  * the logic to determine to which nodes (if any) those shards are allocated.
+ *
+ * @opensearch.internal
  */
 public abstract class BaseGatewayShardAllocator {
 
diff --git a/server/src/main/java/org/opensearch/gateway/ClusterStateUpdaters.java b/server/src/main/java/org/opensearch/gateway/ClusterStateUpdaters.java
index b9913fa5983f7..4c562b348f141 100644
--- a/server/src/main/java/org/opensearch/gateway/ClusterStateUpdaters.java
+++ b/server/src/main/java/org/opensearch/gateway/ClusterStateUpdaters.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -42,6 +41,7 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.common.settings.ClusterSettings;
 
@@ -49,6 +49,11 @@
 
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
 
+/**
+ * Updates cluster state
+ *
+ * @opensearch.internal
+ */
 public class ClusterStateUpdaters {
     private static final Logger logger = LogManager.getLogger(ClusterStateUpdaters.class);
 
@@ -115,8 +120,22 @@ static ClusterState recoverClusterBlocks(final ClusterState state) {
     static ClusterState updateRoutingTable(final ClusterState state) {
         // initialize all index routing tables as empty
         final RoutingTable.Builder routingTableBuilder = RoutingTable.builder(state.routingTable());
-        for (final ObjectCursor<IndexMetadata> cursor : state.metadata().indices().values()) {
-            routingTableBuilder.addAsRecovery(cursor.value);
+        for (final IndexMetadata cursor : state.metadata().indices().values()) {
+            // Whether IndexMetadata is recovered from local disk or remote it doesn't matter to us at this point.
+            // We are only concerned about index data recovery here. Which is why we only check for remote store enabled and not for remote
+            // cluster state enabled.
+            if (cursor.getSettings().getAsBoolean(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false) == false
+                || state.routingTable().hasIndex(cursor.getIndex()) == false
+                || state.routingTable()
+                    .index(cursor.getIndex())
+                    .shardsMatchingPredicateCount(
+                        shardRouting -> shardRouting.primary()
+                            // We need to ensure atleast one of the primaries is being recovered from remote.
+                            // This ensures we have gone through the RemoteStoreRestoreService and routing table is updated
+                            && shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                    ) == 0) {
+                routingTableBuilder.addAsRecovery(cursor);
+            }
         }
         // start with 0 based versions for routing table
         routingTableBuilder.version(0);
diff --git a/server/src/main/java/org/opensearch/gateway/CorruptStateException.java b/server/src/main/java/org/opensearch/gateway/CorruptStateException.java
index 7c5aeb76e5118..3632dc057a053 100644
--- a/server/src/main/java/org/opensearch/gateway/CorruptStateException.java
+++ b/server/src/main/java/org/opensearch/gateway/CorruptStateException.java
@@ -36,6 +36,8 @@
 /**
  * This exception is thrown when OpenSearch detects
  * an inconsistency in one of it's persistent states.
+ *
+ * @opensearch.internal
  */
 public class CorruptStateException extends OpenSearchCorruptionException {
 
diff --git a/server/src/main/java/org/opensearch/gateway/DanglingIndicesState.java b/server/src/main/java/org/opensearch/gateway/DanglingIndicesState.java
index 3baa5bfb9e410..e7c1ba01e7920 100644
--- a/server/src/main/java/org/opensearch/gateway/DanglingIndicesState.java
+++ b/server/src/main/java/org/opensearch/gateway/DanglingIndicesState.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.metadata.IndexGraveyard;
@@ -45,8 +43,9 @@
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -63,6 +62,8 @@
  * The dangling indices state is responsible for finding new dangling indices (indices that have
  * their state written on disk, but don't exists in the metadata of the cluster), and importing
  * them into the cluster.
+ *
+ * @opensearch.internal
  */
 public class DanglingIndicesState implements ClusterStateListener {
 
@@ -189,8 +190,8 @@ void findNewAndAddDanglingIndices(final Metadata metadata) {
      */
     public Map<Index, IndexMetadata> findNewDanglingIndices(Map<Index, IndexMetadata> existingDanglingIndices, final Metadata metadata) {
         final Set<String> excludeIndexPathIds = new HashSet<>(metadata.indices().size() + danglingIndices.size());
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            excludeIndexPathIds.add(cursor.value.getIndex().getUUID());
+        for (final IndexMetadata indexMetadata : metadata.indices().values()) {
+            excludeIndexPathIds.add(indexMetadata.getIndex().getUUID());
         }
         for (Index index : existingDanglingIndices.keySet()) {
             excludeIndexPathIds.add(index.getUUID());
@@ -254,14 +255,14 @@ private IndexMetadata stripAliases(IndexMetadata indexMetadata) {
             logger.info(
                 "[{}] stripping aliases: {} from index before importing",
                 indexMetadata.getIndex(),
-                indexMetadata.getAliases().keys()
+                indexMetadata.getAliases().keySet()
             );
             return IndexMetadata.builder(indexMetadata).removeAllAliases().build();
         }
     }
 
     /**
-     * Allocates the detected list of dangling indices by sending them to the master node
+     * Allocates the detected list of dangling indices by sending them to the cluster-manager node
      * for allocation, provided auto-import is enabled via the
      * {@link #AUTO_IMPORT_DANGLING_INDICES_SETTING} setting.
      * @param metadata the current cluster metadata, used to filter out dangling indices that cannot be allocated
diff --git a/server/src/main/java/org/opensearch/gateway/Gateway.java b/server/src/main/java/org/opensearch/gateway/Gateway.java
index c25097723b8f7..a01f053ce6e9b 100644
--- a/server/src/main/java/org/opensearch/gateway/Gateway.java
+++ b/server/src/main/java/org/opensearch/gateway/Gateway.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.ObjectFloatHashMap;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.action.FailedNodeException;
@@ -42,11 +40,18 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * The Gateway
+ *
+ * @opensearch.internal
+ */
 public class Gateway {
 
     private static final Logger logger = LogManager.getLogger(Gateway.class);
@@ -65,7 +70,7 @@ public Gateway(
     }
 
     public void performStateRecovery(final GatewayStateRecoveredListener listener) throws GatewayException {
-        final String[] nodesIds = clusterService.state().nodes().getMasterNodes().keys().toArray(String.class);
+        final String[] nodesIds = clusterService.state().nodes().getClusterManagerNodes().keySet().toArray(new String[0]);
         logger.trace("performing state recovery from {}", Arrays.toString(nodesIds));
         final TransportNodesListGatewayMetaState.NodesGatewayMetaState nodesState = listGatewayMetaState.list(nodesIds, null).actionGet();
 
@@ -77,7 +82,7 @@ public void performStateRecovery(final GatewayStateRecoveredListener listener) t
             }
         }
 
-        final ObjectFloatHashMap<Index> indices = new ObjectFloatHashMap<>();
+        final Map<Index, Float> indices = new HashMap<>();
         Metadata electedGlobalState = null;
         int found = 0;
         for (final TransportNodesListGatewayMetaState.NodeGatewayMetaState nodeState : nodesState.getNodes()) {
@@ -90,8 +95,8 @@ public void performStateRecovery(final GatewayStateRecoveredListener listener) t
             } else if (nodeState.metadata().version() > electedGlobalState.version()) {
                 electedGlobalState = nodeState.metadata();
             }
-            for (final ObjectCursor<IndexMetadata> cursor : nodeState.metadata().indices().values()) {
-                indices.addTo(cursor.value.getIndex(), 1);
+            for (final IndexMetadata cursor : nodeState.metadata().indices().values()) {
+                indices.merge(cursor.getIndex(), 1f, Float::sum);
             }
         }
         if (found < requiredAllocation) {
@@ -102,7 +107,7 @@ public void performStateRecovery(final GatewayStateRecoveredListener listener) t
         final Metadata.Builder metadataBuilder = Metadata.builder(electedGlobalState).removeAllIndices();
 
         assert !indices.containsKey(null);
-        final Object[] keys = indices.keys;
+        final Object[] keys = indices.keySet().toArray();
         for (int i = 0; i < keys.length; i++) {
             if (keys[i] != null) {
                 final Index index = (Index) keys[i];
@@ -139,6 +144,11 @@ public void performStateRecovery(final GatewayStateRecoveredListener listener) t
         listener.onSuccess(recoveredState);
     }
 
+    /**
+     * The lister for state recovered.
+     *
+     * @opensearch.internal
+     */
     public interface GatewayStateRecoveredListener {
         void onSuccess(ClusterState build);
 
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayAllocator.java b/server/src/main/java/org/opensearch/gateway/GatewayAllocator.java
index 76dc33e73a530..b5a00b1a47523 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayAllocator.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayAllocator.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -53,16 +51,23 @@
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
 
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
+import java.util.Spliterators;
 import java.util.concurrent.ConcurrentMap;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
+/**
+ * Allocator for the gateway
+ *
+ * @opensearch.internal
+ */
 public class GatewayAllocator implements ExistingShardsAllocator {
 
     public static final String ALLOCATOR_NAME = "gateway_allocator";
@@ -198,8 +203,8 @@ public AllocateUnassignedDecision explainUnassignedShardAllocation(ShardRouting
     private void ensureAsyncFetchStorePrimaryRecency(RoutingAllocation allocation) {
         DiscoveryNodes nodes = allocation.nodes();
         if (hasNewNodes(nodes)) {
-            final Set<String> newEphemeralIds = StreamSupport.stream(nodes.getDataNodes().spliterator(), false)
-                .map(node -> node.value.getEphemeralId())
+            final Set<String> newEphemeralIds = StreamSupport.stream(Spliterators.spliterator(nodes.getDataNodes().entrySet(), 0), false)
+                .map(node -> node.getValue().getEphemeralId())
                 .collect(Collectors.toSet());
             // Invalidate the cache if a data node has been added to the cluster. This ensures that we do not cancel a recovery if a node
             // drops out, we fetch the shard data, then some indexing happens and then the node rejoins the cluster again. There are other
@@ -228,8 +233,8 @@ private static void clearCacheForPrimary(
     }
 
     private boolean hasNewNodes(DiscoveryNodes nodes) {
-        for (ObjectObjectCursor<String, DiscoveryNode> node : nodes.getDataNodes()) {
-            if (lastSeenEphemeralIds.contains(node.value.getEphemeralId()) == false) {
+        for (final DiscoveryNode node : nodes.getDataNodes().values()) {
+            if (lastSeenEphemeralIds.contains(node.getEphemeralId()) == false) {
                 return true;
             }
         }
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayException.java b/server/src/main/java/org/opensearch/gateway/GatewayException.java
index 262b45c9bba28..84593d2a1ae9d 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayException.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayException.java
@@ -33,10 +33,15 @@
 package org.opensearch.gateway;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Base Exception for the gateway
+ *
+ * @opensearch.internal
+ */
 public class GatewayException extends OpenSearchException {
 
     public GatewayException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java b/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
index fd978a9c8ed8b..a2b782e81e099 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
@@ -32,14 +32,12 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterName;
@@ -48,6 +46,8 @@
 import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationState.PersistedState;
 import org.opensearch.cluster.coordination.InMemoryPersistedState;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.cluster.metadata.Manifest;
@@ -55,16 +55,20 @@
 import org.opensearch.cluster.metadata.MetadataIndexUpgradeService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.NodeMetadata;
+import org.opensearch.gateway.remote.ClusterMetadataManifest;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.index.recovery.RemoteStoreRestoreService;
+import org.opensearch.index.recovery.RemoteStoreRestoreService.RemoteRestoreResult;
 import org.opensearch.node.Node;
 import org.opensearch.plugins.MetadataUpgrader;
+import org.opensearch.repositories.RepositoryMissingException;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -75,6 +79,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
@@ -83,35 +88,37 @@
 import java.util.function.UnaryOperator;
 
 import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreClusterStateEnabled;
 
 /**
  * Loads (and maybe upgrades) cluster metadata at startup, and persistently stores cluster metadata for future restarts.
  *
- * When started, ensures that this version is compatible with the state stored on disk, and performs a state upgrade if necessary. Note that
- * the state being loaded when constructing the instance of this class is not necessarily the state that will be used as {@link
- * ClusterState#metadata()} because it might be stale or incomplete. Master-eligible nodes must perform an election to find a complete and
- * non-stale state, and master-ineligible nodes receive the real cluster state from the elected master after joining the cluster.
+ * When started, ensures that this version is compatible with the state stored on disk, and performs a state upgrade if necessary. Note that the state being
+ * loaded when constructing the instance of this class is not necessarily the state that will be used as {@link ClusterState#metadata()} because it might be
+ * stale or incomplete. Cluster-manager-eligible nodes must perform an election to find a complete and non-stale state, and cluster-manager-ineligible nodes
+ * receive the real cluster state from the elected cluster-manager after joining the cluster.
+ *
+ * @opensearch.internal
  */
 public class GatewayMetaState implements Closeable {
 
     /**
-     * Fake node ID for a voting configuration written by a master-ineligible data node to indicate that its on-disk state is potentially
-     * stale (since it is written asynchronously after application, rather than before acceptance). This node ID means that if the node is
-     * restarted as a master-eligible node then it does not win any elections until it has received a fresh cluster state.
+     * Fake node ID for a voting configuration written by a cluster-manager-ineligible data node to indicate that its on-disk state is potentially stale (since
+     * it is written asynchronously after application, rather than before acceptance). This node ID means that if the node is restarted as a
+     * cluster-manager-eligible node then it does not win any elections until it has received a fresh cluster state.
      */
     public static final String STALE_STATE_CONFIG_NODE_ID = "STALE_STATE_CONFIG";
 
-    // Set by calling start()
-    private final SetOnce<PersistedState> persistedState = new SetOnce<>();
+    private PersistedStateRegistry persistedStateRegistry;
 
     public PersistedState getPersistedState() {
-        final PersistedState persistedState = this.persistedState.get();
+        final PersistedState persistedState = persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL);
         assert persistedState != null : "not started";
         return persistedState;
     }
 
     public Metadata getMetadata() {
-        return getPersistedState().getLastAcceptedState().metadata();
+        return persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL).getLastAcceptedState().metadata();
     }
 
     public void start(
@@ -121,11 +128,15 @@ public void start(
         MetaStateService metaStateService,
         MetadataIndexUpgradeService metadataIndexUpgradeService,
         MetadataUpgrader metadataUpgrader,
-        PersistedClusterStateService persistedClusterStateService
+        PersistedClusterStateService persistedClusterStateService,
+        RemoteClusterStateService remoteClusterStateService,
+        PersistedStateRegistry persistedStateRegistry,
+        RemoteStoreRestoreService remoteStoreRestoreService
     ) {
-        assert persistedState.get() == null : "should only start once, but already have " + persistedState.get();
+        assert this.persistedStateRegistry == null : "Persisted state registry should only be set once";
+        this.persistedStateRegistry = persistedStateRegistry;
 
-        if (DiscoveryNode.isMasterNode(settings) || DiscoveryNode.isDataNode(settings)) {
+        if (DiscoveryNode.isClusterManagerNode(settings) || DiscoveryNode.isDataNode(settings)) {
             try {
                 final PersistedClusterStateService.OnDiskState onDiskState = persistedClusterStateService.loadBestOnDiskState();
 
@@ -145,9 +156,10 @@ public void start(
                 }
 
                 PersistedState persistedState = null;
+                PersistedState remotePersistedState = null;
                 boolean success = false;
                 try {
-                    final ClusterState clusterState = prepareInitialClusterState(
+                    ClusterState clusterState = prepareInitialClusterState(
                         transportService,
                         clusterService,
                         ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings))
@@ -156,7 +168,29 @@ public void start(
                             .build()
                     );
 
-                    if (DiscoveryNode.isMasterNode(settings)) {
+                    if (DiscoveryNode.isClusterManagerNode(settings)) {
+                        if (isRemoteStoreClusterStateEnabled(settings)) {
+                            // If the cluster UUID loaded from local is unknown (_na_) then fetch the best state from remote
+                            // If there is no valid state on remote, continue with initial empty state
+                            // If there is a valid state, then restore index metadata using this state
+                            String lastKnownClusterUUID = ClusterState.UNKNOWN_UUID;
+                            if (ClusterState.UNKNOWN_UUID.equals(clusterState.metadata().clusterUUID())) {
+                                lastKnownClusterUUID = remoteClusterStateService.getLastKnownUUIDFromRemote(
+                                    clusterState.getClusterName().value()
+                                );
+                                if (ClusterState.UNKNOWN_UUID.equals(lastKnownClusterUUID) == false) {
+                                    // Load state from remote
+                                    final RemoteRestoreResult remoteRestoreResult = remoteStoreRestoreService.restore(
+                                        clusterState,
+                                        lastKnownClusterUUID,
+                                        false,
+                                        new String[] {}
+                                    );
+                                    clusterState = remoteRestoreResult.getClusterState();
+                                }
+                            }
+                            remotePersistedState = new RemotePersistedState(remoteClusterStateService, lastKnownClusterUUID);
+                        }
                         persistedState = new LucenePersistedState(persistedClusterStateService, currentTerm, clusterState);
                     } else {
                         persistedState = new AsyncLucenePersistedState(
@@ -178,11 +212,14 @@ public void start(
                     success = true;
                 } finally {
                     if (success == false) {
-                        IOUtils.closeWhileHandlingException(persistedState);
+                        IOUtils.closeWhileHandlingException(persistedStateRegistry);
                     }
                 }
 
-                this.persistedState.set(persistedState);
+                persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, persistedState);
+                if (remotePersistedState != null) {
+                    persistedStateRegistry.addPersistedState(PersistedStateType.REMOTE, remotePersistedState);
+                }
             } catch (IOException e) {
                 throw new OpenSearchException("failed to load metadata", e);
             }
@@ -209,7 +246,7 @@ public void start(
                     throw new UncheckedIOException(e);
                 }
             }
-            persistedState.set(new InMemoryPersistedState(currentTerm, clusterState));
+            persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, new InMemoryPersistedState(currentTerm, clusterState));
         }
     }
 
@@ -235,8 +272,8 @@ Metadata upgradeMetadataForNode(
     }
 
     /**
-     * This method calls {@link MetadataIndexUpgradeService} to makes sure that indices are compatible with the current
-     * version. The MetadataIndexUpgradeService might also update obsolete settings if needed.
+     * This method calls {@link MetadataIndexUpgradeService} to makes sure that indices are compatible with the current version. The MetadataIndexUpgradeService
+     * might also update obsolete settings if needed.
      *
      * @return input <code>metadata</code> if no upgrade is needed or an upgraded metadata
      */
@@ -269,15 +306,15 @@ static Metadata upgradeMetadata(
     }
 
     private static boolean applyPluginUpgraders(
-        ImmutableOpenMap<String, IndexTemplateMetadata> existingData,
+        final Map<String, IndexTemplateMetadata> existingData,
         UnaryOperator<Map<String, IndexTemplateMetadata>> upgrader,
         Consumer<String> removeData,
         BiConsumer<String, IndexTemplateMetadata> putData
     ) {
         // collect current data
         Map<String, IndexTemplateMetadata> existingMap = new HashMap<>();
-        for (ObjectObjectCursor<String, IndexTemplateMetadata> customCursor : existingData) {
-            existingMap.put(customCursor.key, customCursor.value);
+        for (Map.Entry<String, IndexTemplateMetadata> customCursor : existingData.entrySet()) {
+            existingMap.put(customCursor.getKey(), customCursor.getValue());
         }
         // upgrade global custom meta data
         Map<String, IndexTemplateMetadata> upgradedCustoms = upgrader.apply(existingMap);
@@ -310,7 +347,7 @@ public void applyClusterState(ClusterChangedEvent event) {
             }
 
             try {
-                // Hack: This is to ensure that non-master-eligible Zen2 nodes always store a current term
+                // Hack: This is to ensure that non-cluster-manager-eligible Zen2 nodes always store a current term
                 // that's higher than the last accepted term.
                 // TODO: can we get rid of this hack?
                 if (event.state().term() > incrementalClusterStateWriter.getPreviousManifest().getCurrentTerm()) {
@@ -328,12 +365,14 @@ public void applyClusterState(ClusterChangedEvent event) {
 
     @Override
     public void close() throws IOException {
-        IOUtils.close(persistedState.get());
+        IOUtils.close(persistedStateRegistry);
     }
 
     // visible for testing
     public boolean allPendingAsyncStatesWritten() {
-        final PersistedState ps = persistedState.get();
+        // This method is invoked for persisted state implementations which write asynchronously.
+        // RemotePersistedState is invoked in synchronous path. So this logic is not required for remote state.
+        final PersistedState ps = persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL);
         if (ps instanceof AsyncLucenePersistedState) {
             return ((AsyncLucenePersistedState) ps).allPendingAsyncStatesWritten();
         } else {
@@ -502,8 +541,8 @@ static class LucenePersistedState implements PersistedState {
             // (2) the index is currently empty since it was opened with IndexWriterConfig.OpenMode.CREATE
 
             // In the common case it's actually sufficient to commit() the existing state and not do any indexing. For instance,
-            // this is true if there's only one data path on this master node, and the commit we just loaded was already written out
-            // by this version of OpenSearch. TODO TBD should we avoid indexing when possible?
+            // this is true if there's only one data path on this cluster-manager node, and the commit we just loaded was already written
+            // out by this version of OpenSearch. TODO TBD should we avoid indexing when possible?
             final PersistedClusterStateService.Writer writer = persistedClusterStateService.createWriter();
             try {
                 writer.writeFullStateAndCommit(currentTerm, lastAcceptedState);
@@ -600,4 +639,139 @@ public void close() throws IOException {
             IOUtils.close(persistenceWriter.getAndSet(null));
         }
     }
+
+    /**
+     * Encapsulates the writing of metadata to a remote store using {@link RemoteClusterStateService}.
+     */
+    public static class RemotePersistedState implements PersistedState {
+
+        private static final Logger logger = LogManager.getLogger(RemotePersistedState.class);
+
+        private ClusterState lastAcceptedState;
+        private ClusterMetadataManifest lastAcceptedManifest;
+        private final RemoteClusterStateService remoteClusterStateService;
+        private String previousClusterUUID;
+
+        public RemotePersistedState(final RemoteClusterStateService remoteClusterStateService, final String previousClusterUUID) {
+            this.remoteClusterStateService = remoteClusterStateService;
+            this.previousClusterUUID = previousClusterUUID;
+        }
+
+        @Override
+        public long getCurrentTerm() {
+            return lastAcceptedState != null ? lastAcceptedState.term() : 0L;
+        }
+
+        @Override
+        public ClusterState getLastAcceptedState() {
+            return lastAcceptedState;
+        }
+
+        @Override
+        public void setCurrentTerm(long currentTerm) {
+            // no-op
+            // For LucenePersistedState, setCurrentTerm is used only while handling StartJoinRequest by all follower nodes.
+            // But for RemotePersistedState, the state is only pushed by the active cluster. So this method is not required.
+        }
+
+        @Override
+        public void setLastAcceptedState(ClusterState clusterState) {
+            try {
+                final ClusterMetadataManifest manifest;
+                if (shouldWriteFullClusterState(clusterState)) {
+                    if (clusterState.metadata().clusterUUIDCommitted() == true) {
+                        final Optional<ClusterMetadataManifest> latestManifest = remoteClusterStateService.getLatestClusterMetadataManifest(
+                            clusterState.getClusterName().value(),
+                            clusterState.metadata().clusterUUID()
+                        );
+                        if (latestManifest.isPresent()) {
+                            // The previous UUID should not change for the current UUID. So fetching the latest manifest
+                            // from remote store and getting the previous UUID.
+                            previousClusterUUID = latestManifest.get().getPreviousClusterUUID();
+                        } else {
+                            // When the user starts the cluster with remote state disabled but later enables the remote state,
+                            // there will not be any manifest for the current cluster UUID.
+                            logger.error(
+                                "Latest manifest is not present in remote store for cluster UUID: {}",
+                                clusterState.metadata().clusterUUID()
+                            );
+                            previousClusterUUID = ClusterState.UNKNOWN_UUID;
+                        }
+                    }
+                    manifest = remoteClusterStateService.writeFullMetadata(clusterState, previousClusterUUID);
+                } else {
+                    assert verifyManifestAndClusterState(lastAcceptedManifest, lastAcceptedState) == true
+                        : "Previous manifest and previous ClusterState are not in sync";
+                    manifest = remoteClusterStateService.writeIncrementalMetadata(lastAcceptedState, clusterState, lastAcceptedManifest);
+                }
+                assert verifyManifestAndClusterState(manifest, clusterState) == true : "Manifest and ClusterState are not in sync";
+                lastAcceptedManifest = manifest;
+                lastAcceptedState = clusterState;
+            } catch (RepositoryMissingException e) {
+                // TODO This logic needs to be modified once PR for repo registration during bootstrap is pushed
+                // https://github.com/opensearch-project/OpenSearch/pull/9105/
+                // After the above PR is pushed, we can remove this silent failure and throw the exception instead.
+                logger.error("Remote repository is not yet registered");
+                lastAcceptedState = clusterState;
+            } catch (Exception e) {
+                handleExceptionOnWrite(e);
+            }
+        }
+
+        private boolean verifyManifestAndClusterState(ClusterMetadataManifest manifest, ClusterState clusterState) {
+            assert manifest != null : "ClusterMetadataManifest is null";
+            assert clusterState != null : "ClusterState is null";
+            assert clusterState.metadata().indices().size() == manifest.getIndices().size()
+                : "Number of indices in last accepted state and manifest are different";
+            manifest.getIndices().stream().forEach(md -> {
+                assert clusterState.metadata().indices().containsKey(md.getIndexName())
+                    : "Last accepted state does not contain the index : " + md.getIndexName();
+                assert clusterState.metadata().indices().get(md.getIndexName()).getIndexUUID().equals(md.getIndexUUID())
+                    : "Last accepted state and manifest do not have same UUID for index : " + md.getIndexName();
+            });
+            return true;
+        }
+
+        private boolean shouldWriteFullClusterState(ClusterState clusterState) {
+            if (lastAcceptedState == null
+                || lastAcceptedManifest == null
+                || lastAcceptedState.term() != clusterState.term()
+                || lastAcceptedManifest.getOpensearchVersion() != Version.CURRENT) {
+                return true;
+            }
+            return false;
+        }
+
+        @Override
+        public void markLastAcceptedStateAsCommitted() {
+            try {
+                assert lastAcceptedState != null : "Last accepted state is not present";
+                assert lastAcceptedManifest != null : "Last accepted manifest is not present";
+                ClusterState clusterState = lastAcceptedState;
+                if (lastAcceptedState.metadata().clusterUUID().equals(Metadata.UNKNOWN_CLUSTER_UUID) == false
+                    && lastAcceptedState.metadata().clusterUUIDCommitted() == false) {
+                    Metadata.Builder metadataBuilder = Metadata.builder(lastAcceptedState.metadata());
+                    metadataBuilder.clusterUUIDCommitted(true);
+                    clusterState = ClusterState.builder(lastAcceptedState).metadata(metadataBuilder).build();
+                }
+                final ClusterMetadataManifest committedManifest = remoteClusterStateService.markLastStateAsCommitted(
+                    clusterState,
+                    lastAcceptedManifest
+                );
+                lastAcceptedManifest = committedManifest;
+                lastAcceptedState = clusterState;
+            } catch (Exception e) {
+                handleExceptionOnWrite(e);
+            }
+        }
+
+        @Override
+        public void close() throws IOException {
+            remoteClusterStateService.close();
+        }
+
+        private void handleExceptionOnWrite(Exception e) {
+            throw ExceptionsHelper.convertToRuntime(e);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayModule.java b/server/src/main/java/org/opensearch/gateway/GatewayModule.java
index a58fe3657d27d..59ec0243c88c9 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayModule.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayModule.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.inject.AbstractModule;
 
+/**
+ * Binds the gateway module
+ *
+ * @opensearch.internal
+ */
 public class GatewayModule extends AbstractModule {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayService.java b/server/src/main/java/org/opensearch/gateway/GatewayService.java
index 47347cea50e27..7f95d7afe90c7 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayService.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayService.java
@@ -46,20 +46,25 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.discovery.Discovery;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Function;
 
+/**
+ * The Gateway Service provider
+ *
+ * @opensearch.internal
+ */
 public class GatewayService extends AbstractLifecycleComponent implements ClusterStateListener {
     private static final Logger logger = LogManager.getLogger(GatewayService.class);
 
@@ -132,8 +137,8 @@ public class GatewayService extends AbstractLifecycleComponent implements Cluste
     private final int expectedNodes;
     private final int recoverAfterDataNodes;
     private final int expectedDataNodes;
-    private final int recoverAfterMasterNodes;
-    private final int expectedMasterNodes;
+    private final int recoverAfterClusterManagerNodes;
+    private final int expectedClusterManagerNodes;
 
     private final Runnable recoveryRunnable;
 
@@ -155,22 +160,22 @@ public GatewayService(
         // allow to control a delay of when indices will get created
         this.expectedNodes = EXPECTED_NODES_SETTING.get(settings);
         this.expectedDataNodes = EXPECTED_DATA_NODES_SETTING.get(settings);
-        this.expectedMasterNodes = EXPECTED_MASTER_NODES_SETTING.get(settings);
+        this.expectedClusterManagerNodes = EXPECTED_MASTER_NODES_SETTING.get(settings);
 
         if (RECOVER_AFTER_TIME_SETTING.exists(settings)) {
             recoverAfterTime = RECOVER_AFTER_TIME_SETTING.get(settings);
-        } else if (expectedNodes >= 0 || expectedDataNodes >= 0 || expectedMasterNodes >= 0) {
+        } else if (expectedNodes >= 0 || expectedDataNodes >= 0 || expectedClusterManagerNodes >= 0) {
             recoverAfterTime = DEFAULT_RECOVER_AFTER_TIME_IF_EXPECTED_NODES_IS_SET;
         } else {
             recoverAfterTime = null;
         }
         this.recoverAfterNodes = RECOVER_AFTER_NODES_SETTING.get(settings);
         this.recoverAfterDataNodes = RECOVER_AFTER_DATA_NODES_SETTING.get(settings);
-        // default the recover after master nodes to the minimum master nodes in the discovery
+        // default the recover after cluster-manager nodes to the minimum cluster-manager nodes in the discovery
         if (RECOVER_AFTER_MASTER_NODES_SETTING.exists(settings)) {
-            recoverAfterMasterNodes = RECOVER_AFTER_MASTER_NODES_SETTING.get(settings);
+            recoverAfterClusterManagerNodes = RECOVER_AFTER_MASTER_NODES_SETTING.get(settings);
         } else {
-            recoverAfterMasterNodes = -1;
+            recoverAfterClusterManagerNodes = -1;
         }
 
         if (discovery instanceof Coordinator) {
@@ -183,7 +188,7 @@ public GatewayService(
 
     @Override
     protected void doStart() {
-        if (DiscoveryNode.isMasterNode(clusterService.getSettings())) {
+        if (DiscoveryNode.isClusterManagerNode(clusterService.getSettings())) {
             // use post applied so that the state will be visible to the background recovery thread we spawn in performStateRecovery
             clusterService.addListener(this);
         }
@@ -205,7 +210,7 @@ public void clusterChanged(final ClusterChangedEvent event) {
 
         final ClusterState state = event.state();
 
-        if (state.nodes().isLocalNodeElectedMaster() == false) {
+        if (state.nodes().isLocalNodeElectedClusterManager() == false) {
             // not our job to recover
             return;
         }
@@ -215,12 +220,12 @@ public void clusterChanged(final ClusterChangedEvent event) {
         }
 
         final DiscoveryNodes nodes = state.nodes();
-        if (state.nodes().getMasterNodeId() == null) {
-            logger.debug("not recovering from gateway, no master elected yet");
-        } else if (recoverAfterNodes != -1 && (nodes.getMasterAndDataNodes().size()) < recoverAfterNodes) {
+        if (state.nodes().getClusterManagerNodeId() == null) {
+            logger.debug("not recovering from gateway, no cluster-manager elected yet");
+        } else if (recoverAfterNodes != -1 && (nodes.getClusterManagerAndDataNodes().size()) < recoverAfterNodes) {
             logger.debug(
                 "not recovering from gateway, nodes_size (data+master) [{}] < recover_after_nodes [{}]",
-                nodes.getMasterAndDataNodes().size(),
+                nodes.getClusterManagerAndDataNodes().size(),
                 recoverAfterNodes
             );
         } else if (recoverAfterDataNodes != -1 && nodes.getDataNodes().size() < recoverAfterDataNodes) {
@@ -229,16 +234,16 @@ public void clusterChanged(final ClusterChangedEvent event) {
                 nodes.getDataNodes().size(),
                 recoverAfterDataNodes
             );
-        } else if (recoverAfterMasterNodes != -1 && nodes.getMasterNodes().size() < recoverAfterMasterNodes) {
+        } else if (recoverAfterClusterManagerNodes != -1 && nodes.getClusterManagerNodes().size() < recoverAfterClusterManagerNodes) {
             logger.debug(
                 "not recovering from gateway, nodes_size (master) [{}] < recover_after_master_nodes [{}]",
-                nodes.getMasterNodes().size(),
-                recoverAfterMasterNodes
+                nodes.getClusterManagerNodes().size(),
+                recoverAfterClusterManagerNodes
             );
         } else {
             boolean enforceRecoverAfterTime;
             String reason;
-            if (expectedNodes == -1 && expectedMasterNodes == -1 && expectedDataNodes == -1) {
+            if (expectedNodes == -1 && expectedClusterManagerNodes == -1 && expectedDataNodes == -1) {
                 // no expected is set, honor the setting if they are there
                 enforceRecoverAfterTime = true;
                 reason = "recover_after_time was set to [" + recoverAfterTime + "]";
@@ -246,16 +251,25 @@ public void clusterChanged(final ClusterChangedEvent event) {
                 // one of the expected is set, see if all of them meet the need, and ignore the timeout in this case
                 enforceRecoverAfterTime = false;
                 reason = "";
-                if (expectedNodes != -1 && (nodes.getMasterAndDataNodes().size() < expectedNodes)) { // does not meet the expected...
+                if (expectedNodes != -1 && (nodes.getClusterManagerAndDataNodes().size() < expectedNodes)) { // does not meet the
+                                                                                                             // expected...
                     enforceRecoverAfterTime = true;
-                    reason = "expecting [" + expectedNodes + "] nodes, but only have [" + nodes.getMasterAndDataNodes().size() + "]";
+                    reason = "expecting ["
+                        + expectedNodes
+                        + "] nodes, but only have ["
+                        + nodes.getClusterManagerAndDataNodes().size()
+                        + "]";
                 } else if (expectedDataNodes != -1 && (nodes.getDataNodes().size() < expectedDataNodes)) { // does not meet the expected...
                     enforceRecoverAfterTime = true;
                     reason = "expecting [" + expectedDataNodes + "] data nodes, but only have [" + nodes.getDataNodes().size() + "]";
-                } else if (expectedMasterNodes != -1 && (nodes.getMasterNodes().size() < expectedMasterNodes)) {
+                } else if (expectedClusterManagerNodes != -1 && (nodes.getClusterManagerNodes().size() < expectedClusterManagerNodes)) {
                     // does not meet the expected...
                     enforceRecoverAfterTime = true;
-                    reason = "expecting [" + expectedMasterNodes + "] master nodes, but only have [" + nodes.getMasterNodes().size() + "]";
+                    reason = "expecting ["
+                        + expectedClusterManagerNodes
+                        + "] cluster-manager nodes, but only have ["
+                        + nodes.getClusterManagerNodes().size()
+                        + "]";
                 }
             }
             performStateRecovery(enforceRecoverAfterTime, reason);
@@ -332,8 +346,8 @@ public void clusterStateProcessed(final String source, final ClusterState oldSta
         }
 
         @Override
-        public void onNoLongerMaster(String source) {
-            logger.debug("stepped down as master before recovering state [{}]", source);
+        public void onNoLongerClusterManager(String source) {
+            logger.debug("stepped down as cluster-manager before recovering state [{}]", source);
             resetRecoveredFlags();
         }
 
diff --git a/server/src/main/java/org/opensearch/gateway/IncrementalClusterStateWriter.java b/server/src/main/java/org/opensearch/gateway/IncrementalClusterStateWriter.java
index 4c1a921e9c4ac..ec599df7f7426 100644
--- a/server/src/main/java/org/opensearch/gateway/IncrementalClusterStateWriter.java
+++ b/server/src/main/java/org/opensearch/gateway/IncrementalClusterStateWriter.java
@@ -42,7 +42,7 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -54,6 +54,8 @@
 
 /**
  * Tracks the metadata written to disk, allowing updated metadata to be written incrementally (i.e. only writing out the changed metadata).
+ *
+ * @opensearch.internal
  */
 public class IncrementalClusterStateWriter {
 
@@ -333,7 +335,8 @@ void writeManifestAndCleanup(String reason, Manifest manifest) throws WriteState
             } catch (WriteStateException e) {
                 // If the Manifest write results in a dirty WriteStateException it's not safe to roll back, removing the new metadata files,
                 // because if the Manifest was actually written to disk and its deletion fails it will reference these new metadata files.
-                // On master-eligible nodes a dirty WriteStateException here is fatal to the node since we no longer really have any idea
+                // On cluster-manager-eligible nodes a dirty WriteStateException here is fatal to the node since we no longer really have
+                // any idea
                 // what the state on disk is and the only sensible response is to start again from scratch.
                 if (e.isDirty() == false) {
                     rollback();
diff --git a/server/src/main/java/org/opensearch/gateway/LocalAllocateDangledIndices.java b/server/src/main/java/org/opensearch/gateway/LocalAllocateDangledIndices.java
index c8ace3d218864..3c5fb881a8a83 100644
--- a/server/src/main/java/org/opensearch/gateway/LocalAllocateDangledIndices.java
+++ b/server/src/main/java/org/opensearch/gateway/LocalAllocateDangledIndices.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
@@ -50,16 +49,17 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.discovery.MasterNotDiscoveredException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
@@ -68,6 +68,11 @@
 
 import static org.opensearch.cluster.metadata.MetadataIndexStateService.isIndexVerifiedBeforeClosed;
 
+/**
+ * Allocates dangled indices
+ *
+ * @opensearch.internal
+ */
 public class LocalAllocateDangledIndices {
 
     private static final Logger logger = LogManager.getLogger(LocalAllocateDangledIndices.class);
@@ -103,9 +108,9 @@ public LocalAllocateDangledIndices(
 
     public void allocateDangled(Collection<IndexMetadata> indices, ActionListener<AllocateDangledResponse> listener) {
         ClusterState clusterState = clusterService.state();
-        DiscoveryNode masterNode = clusterState.nodes().getMasterNode();
-        if (masterNode == null) {
-            listener.onFailure(new MasterNotDiscoveredException("no master to send allocate dangled request"));
+        DiscoveryNode clusterManagerNode = clusterState.nodes().getClusterManagerNode();
+        if (clusterManagerNode == null) {
+            listener.onFailure(new ClusterManagerNotDiscoveredException("no cluster-manager to send allocate dangled request"));
             return;
         }
         AllocateDangledRequest request = new AllocateDangledRequest(
@@ -113,7 +118,7 @@ public void allocateDangled(Collection<IndexMetadata> indices, ActionListener<Al
             indices.toArray(new IndexMetadata[indices.size()])
         );
         transportService.sendRequest(
-            masterNode,
+            clusterManagerNode,
             ACTION_NAME,
             request,
             new ActionListenerResponseHandler<>(listener, AllocateDangledResponse::new, ThreadPool.Names.SAME)
@@ -160,7 +165,7 @@ public ClusterState execute(ClusterState currentState) {
                                 indexMetadata.getIndex(),
                                 request.fromNode,
                                 indexMetadata.getCreationVersion(),
-                                currentState.getNodes().getMasterNode().getVersion()
+                                currentState.getNodes().getClusterManagerNode().getVersion()
                             );
                             continue;
                         }
@@ -261,6 +266,12 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         }
     }
 
+    /**
+     * The request.
+     *
+     * @opensearch.internal
+     */
+
     public static class AllocateDangledRequest extends TransportRequest {
 
         DiscoveryNode fromNode;
@@ -285,6 +296,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * The response.
+     *
+     * @opensearch.internal
+     */
     public static class AllocateDangledResponse extends TransportResponse {
 
         private boolean ack;
diff --git a/server/src/main/java/org/opensearch/gateway/MetaStateService.java b/server/src/main/java/org/opensearch/gateway/MetaStateService.java
index eb5a4adba9b0f..94bfdae151427 100644
--- a/server/src/main/java/org/opensearch/gateway/MetaStateService.java
+++ b/server/src/main/java/org/opensearch/gateway/MetaStateService.java
@@ -41,9 +41,9 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,6 +54,8 @@
 
 /**
  * Handles writing and loading {@link Manifest}, {@link Metadata} and {@link IndexMetadata}
+ *
+ * @opensearch.internal
  */
 public class MetaStateService {
     private static final Logger logger = LogManager.getLogger(MetaStateService.class);
diff --git a/server/src/main/java/org/opensearch/gateway/MetadataStateFormat.java b/server/src/main/java/org/opensearch/gateway/MetadataStateFormat.java
index fd1dee46815a8..ad47ca66129bb 100644
--- a/server/src/main/java/org/opensearch/gateway/MetadataStateFormat.java
+++ b/server/src/main/java/org/opensearch/gateway/MetadataStateFormat.java
@@ -48,13 +48,13 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lucene.store.IndexOutputOutputStream;
 import org.opensearch.common.lucene.store.InputStreamIndexInput;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -75,6 +75,8 @@
  * MetadataStateFormat is a base class to write checksummed
  * XContent based files to one or more directories in a standardized directory structure.
  * @param <T> the type of the XContent base data-structure
+ *
+ * @opensearch.internal
  */
 public abstract class MetadataStateFormat<T> {
     public static final XContentType FORMAT = XContentType.SMILE;
@@ -286,7 +288,7 @@ private long write(final T state, boolean cleanup, final Path... locations) thro
     }
 
     protected XContentBuilder newXContentBuilder(XContentType type, OutputStream stream) throws IOException {
-        return XContentFactory.contentBuilder(type, stream);
+        return MediaTypeRegistry.contentBuilder(type, stream);
     }
 
     /**
@@ -319,7 +321,7 @@ public final T read(NamedXContentRegistry namedXContentRegistry, Path file) thro
                 long contentSize = indexInput.length() - CodecUtil.footerLength() - filePointer;
                 try (IndexInput slice = indexInput.slice("state_xcontent", filePointer, contentSize)) {
                     try (
-                        XContentParser parser = XContentFactory.xContent(FORMAT)
+                        XContentParser parser = FORMAT.xContent()
                             .createParser(
                                 namedXContentRegistry,
                                 LoggingDeprecationHandler.INSTANCE,
diff --git a/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java b/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
index 8ccf6375239a2..8db4736bcdc40 100644
--- a/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
+++ b/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -46,6 +45,7 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SerialMergeScheduler;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexSearcher;
@@ -60,14 +60,13 @@
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.RecyclingBytesStreamOutput;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.lease.Releasable;
@@ -78,18 +77,19 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
-import org.opensearch.index.Index;
 
 import java.io.Closeable;
 import java.io.IOError;
@@ -108,7 +108,7 @@
 import java.util.function.Supplier;
 
 /**
- * Stores cluster metadata in a bare Lucene index (per data path) split across a number of documents. This is used by master-eligible nodes
+ * Stores cluster metadata in a bare Lucene index (per data path) split across a number of documents. This is used by cluster-manager-eligible nodes
  * to record the last-accepted cluster state during publication. The metadata is written incrementally where possible, leaving alone any
  * documents that have not changed. The index has the following fields:
  *
@@ -131,6 +131,8 @@
  * +---------------------------+-------------------------+-------------------------------------------------------------------------------+
  *
  * (the last-accepted term is recorded in Metadata → CoordinationMetadata so does not need repeating here)
+ *
+ * @opensearch.internal
  */
 public class PersistedClusterStateService {
     private static final Logger logger = LogManager.getLogger(PersistedClusterStateService.class);
@@ -266,6 +268,11 @@ public Path[] getDataPaths() {
         return dataPaths;
     }
 
+    /**
+     * The on disk state.
+     *
+     * @opensearch.internal
+     */
     public static class OnDiskState {
         private static final OnDiskState NO_ON_DISK_STATE = new OnDiskState(null, null, 0L, 0L, Metadata.EMPTY_METADATA);
 
@@ -441,7 +448,7 @@ private OnDiskState loadOnDiskState(Path dataPath, DirectoryReader reader) throw
         final SetOnce<Metadata.Builder> builderReference = new SetOnce<>();
         consumeFromType(searcher, GLOBAL_TYPE_NAME, bytes -> {
             final Metadata metadata = Metadata.Builder.fromXContent(
-                XContentFactory.xContent(XContentType.SMILE)
+                XContentType.SMILE.xContent()
                     .createParser(namedXContentRegistry, LoggingDeprecationHandler.INSTANCE, bytes.bytes, bytes.offset, bytes.length)
             );
             logger.trace("found global metadata with last-accepted term [{}]", metadata.coordinationMetadata().term());
@@ -461,7 +468,7 @@ private OnDiskState loadOnDiskState(Path dataPath, DirectoryReader reader) throw
         final Set<String> indexUUIDs = new HashSet<>();
         consumeFromType(searcher, INDEX_TYPE_NAME, bytes -> {
             final IndexMetadata indexMetadata = IndexMetadata.fromXContent(
-                XContentFactory.xContent(XContentType.SMILE)
+                XContentType.SMILE.xContent()
                     .createParser(namedXContentRegistry, LoggingDeprecationHandler.INSTANCE, bytes.bytes, bytes.offset, bytes.length)
             );
             logger.trace("found index metadata for {}", indexMetadata.getIndex());
@@ -501,12 +508,11 @@ private static void consumeFromType(IndexSearcher indexSearcher, String type, Ch
                 final Bits liveDocs = leafReaderContext.reader().getLiveDocs();
                 final IntPredicate isLiveDoc = liveDocs == null ? i -> true : liveDocs::get;
                 final DocIdSetIterator docIdSetIterator = scorer.iterator();
+                final StoredFields storedFields = leafReaderContext.reader().storedFields();
                 while (docIdSetIterator.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
                     if (isLiveDoc.test(docIdSetIterator.docID())) {
                         logger.trace("processing doc {}", docIdSetIterator.docID());
-                        bytesRefConsumer.accept(
-                            leafReaderContext.reader().document(docIdSetIterator.docID()).getBinaryValue(DATA_FIELD_NAME)
-                        );
+                        bytesRefConsumer.accept(storedFields.document(docIdSetIterator.docID()).getBinaryValue(DATA_FIELD_NAME));
                     }
                 }
             }
@@ -583,6 +589,11 @@ public void close() throws IOException {
         }
     }
 
+    /**
+     * Writer for cluster state service
+     *
+     * @opensearch.internal
+     */
     public static class Writer implements Closeable {
 
         private final List<MetadataIndexWriter> metadataIndexWriters;
@@ -733,8 +744,7 @@ private WriterStats updateMetadata(Metadata previouslyWrittenMetadata, Metadata
                 }
 
                 final Map<String, Long> indexMetadataVersionByUUID = new HashMap<>(previouslyWrittenMetadata.indices().size());
-                for (ObjectCursor<IndexMetadata> cursor : previouslyWrittenMetadata.indices().values()) {
-                    final IndexMetadata indexMetadata = cursor.value;
+                for (final IndexMetadata indexMetadata : previouslyWrittenMetadata.indices().values()) {
                     final Long previousValue = indexMetadataVersionByUUID.putIfAbsent(
                         indexMetadata.getIndexUUID(),
                         indexMetadata.getVersion()
@@ -744,8 +754,7 @@ private WriterStats updateMetadata(Metadata previouslyWrittenMetadata, Metadata
 
                 int numIndicesUpdated = 0;
                 int numIndicesUnchanged = 0;
-                for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-                    final IndexMetadata indexMetadata = cursor.value;
+                for (final IndexMetadata indexMetadata : metadata.indices().values()) {
                     final Long previousVersion = indexMetadataVersionByUUID.get(indexMetadata.getIndexUUID());
                     if (previousVersion == null || indexMetadata.getVersion() != previousVersion) {
                         logger.trace(
@@ -805,8 +814,7 @@ private WriterStats addMetadata(Metadata metadata) throws IOException {
                     metadataIndexWriter.updateGlobalMetadata(globalMetadataDocument);
                 }
 
-                for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-                    final IndexMetadata indexMetadata = cursor.value;
+                for (final IndexMetadata indexMetadata : metadata.indices().values()) {
                     final Document indexMetadataDocument = makeIndexMetadataDocument(indexMetadata, documentBuffer);
                     for (MetadataIndexWriter metadataIndexWriter : metadataIndexWriters) {
                         metadataIndexWriter.updateIndexMetadataDocument(indexMetadataDocument, indexMetadata.getIndex());
@@ -913,7 +921,7 @@ private Document makeDocument(String typeName, ToXContent metadata, DocumentBuff
 
             try (RecyclingBytesStreamOutput streamOutput = documentBuffer.streamOutput()) {
                 try (
-                    XContentBuilder xContentBuilder = XContentFactory.contentBuilder(
+                    XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(
                         XContentType.SMILE,
                         Streams.flushOnCloseStream(streamOutput)
                     )
diff --git a/server/src/main/java/org/opensearch/gateway/PrimaryShardAllocator.java b/server/src/main/java/org/opensearch/gateway/PrimaryShardAllocator.java
index dbde8abf02d6d..4dc9396751fc9 100644
--- a/server/src/main/java/org/opensearch/gateway/PrimaryShardAllocator.java
+++ b/server/src/main/java/org/opensearch/gateway/PrimaryShardAllocator.java
@@ -74,6 +74,8 @@
  * (see {@link org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator}),
  * nor does it allocate primaries when a primary shard failed and there is a valid replica
  * copy that can immediately be promoted to primary, as this takes place in {@link RoutingNodes#failShard}.
+ *
+ * @opensearch.internal
  */
 public abstract class PrimaryShardAllocator extends BaseGatewayShardAllocator {
     /**
@@ -311,6 +313,11 @@ private static ShardStoreInfo shardStoreInfo(NodeGatewayStartedShards nodeShardS
         NodeGatewayStartedShards::primary
     ).reversed();
 
+    private static final Comparator<NodeGatewayStartedShards> HIGHEST_REPLICATION_CHECKPOINT_FIRST_COMPARATOR = Comparator.comparing(
+        NodeGatewayStartedShards::replicationCheckpoint,
+        Comparator.nullsLast(Comparator.naturalOrder())
+    );
+
     /**
      * Builds a list of nodes. If matchAnyShard is set to false, only nodes that have an allocation id matching
      * inSyncAllocationIds are added to the list. Otherwise, any node that has a shard is added to the list, but
@@ -379,6 +386,12 @@ protected static NodeShardsResult buildNodeShardsResult(
             }
         }
 
+        /**
+         * Orders the active shards copies based on below comparators
+         * 1. No store exception i.e. shard copy is readable
+         * 2. Prefer previous primary shard
+         * 3. Prefer shard copy with the highest replication checkpoint. It is NO-OP for doc rep enabled indices.
+         */
         final Comparator<NodeGatewayStartedShards> comparator; // allocation preference
         if (matchAnyShard) {
             // prefer shards with matching allocation ids
@@ -386,9 +399,11 @@ protected static NodeShardsResult buildNodeShardsResult(
                 (NodeGatewayStartedShards state) -> inSyncAllocationIds.contains(state.allocationId())
             ).reversed();
             comparator = matchingAllocationsFirst.thenComparing(NO_STORE_EXCEPTION_FIRST_COMPARATOR)
-                .thenComparing(PRIMARY_FIRST_COMPARATOR);
+                .thenComparing(PRIMARY_FIRST_COMPARATOR)
+                .thenComparing(HIGHEST_REPLICATION_CHECKPOINT_FIRST_COMPARATOR);
         } else {
-            comparator = NO_STORE_EXCEPTION_FIRST_COMPARATOR.thenComparing(PRIMARY_FIRST_COMPARATOR);
+            comparator = NO_STORE_EXCEPTION_FIRST_COMPARATOR.thenComparing(PRIMARY_FIRST_COMPARATOR)
+                .thenComparing(HIGHEST_REPLICATION_CHECKPOINT_FIRST_COMPARATOR);
         }
 
         nodeShardStates.sort(comparator);
diff --git a/server/src/main/java/org/opensearch/gateway/PriorityComparator.java b/server/src/main/java/org/opensearch/gateway/PriorityComparator.java
index cf4cbf53daa37..7b8d2ca8e2787 100644
--- a/server/src/main/java/org/opensearch/gateway/PriorityComparator.java
+++ b/server/src/main/java/org/opensearch/gateway/PriorityComparator.java
@@ -36,7 +36,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Comparator;
 
@@ -51,6 +51,8 @@
  *     <li>Lastly the index names are compared, which is useful when a date is baked into the index
  *         name, e.g. <code>logstash-2015.05.03</code></li>
  * </ol>
+ *
+ * @opensearch.internal
  */
 public abstract class PriorityComparator implements Comparator<ShardRouting> {
 
diff --git a/server/src/main/java/org/opensearch/gateway/ReplicaShardAllocator.java b/server/src/main/java/org/opensearch/gateway/ReplicaShardAllocator.java
index 64146201e29db..a6c9319b6dc54 100644
--- a/server/src/main/java/org/opensearch/gateway/ReplicaShardAllocator.java
+++ b/server/src/main/java/org/opensearch/gateway/ReplicaShardAllocator.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.gateway;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
@@ -49,8 +48,8 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata.NodeStoreFilesMetadata;
@@ -65,6 +64,11 @@
 
 import static org.opensearch.cluster.routing.UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING;
 
+/**
+ * Allocates replica shards
+ *
+ * @opensearch.internal
+ */
 public abstract class ReplicaShardAllocator extends BaseGatewayShardAllocator {
     /**
      * Process existing recoveries of replicas and see if we need to cancel them if we find a better
@@ -304,8 +308,8 @@ private static Tuple<Decision, Map<String, NodeAllocationResult>> canBeAllocated
         Decision madeDecision = Decision.NO;
         final boolean explain = allocation.debugDecision();
         Map<String, NodeAllocationResult> nodeDecisions = explain ? new HashMap<>() : null;
-        for (ObjectCursor<DiscoveryNode> cursor : allocation.nodes().getDataNodes().values()) {
-            RoutingNode node = allocation.routingNodes().node(cursor.value.getId());
+        for (final DiscoveryNode cursor : allocation.nodes().getDataNodes().values()) {
+            RoutingNode node = allocation.routingNodes().node(cursor.getId());
             if (node == null) {
                 continue;
             }
diff --git a/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayMetaState.java b/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayMetaState.java
index ce78962ef7843..bbbc8be534a96 100644
--- a/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayMetaState.java
+++ b/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayMetaState.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.gateway;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
@@ -47,16 +46,22 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Lists gateway meta state
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesListGatewayMetaState extends TransportNodesAction<
     TransportNodesListGatewayMetaState.Request,
     TransportNodesListGatewayMetaState.NodesGatewayMetaState,
@@ -116,6 +121,11 @@ protected NodeGatewayMetaState nodeOperation(NodeRequest request) {
         return new NodeGatewayMetaState(clusterService.localNode(), metaState.getMetadata());
     }
 
+    /**
+     * The request.
+     *
+     * @opensearch.internal
+     */
     public static class Request extends BaseNodesRequest<Request> {
 
         public Request(StreamInput in) throws IOException {
@@ -127,6 +137,11 @@ public Request(String... nodesIds) {
         }
     }
 
+    /**
+     * The nodes gateway metastate.
+     *
+     * @opensearch.internal
+     */
     public static class NodesGatewayMetaState extends BaseNodesResponse<NodeGatewayMetaState> {
 
         public NodesGatewayMetaState(StreamInput in) throws IOException {
@@ -148,6 +163,11 @@ protected void writeNodesTo(StreamOutput out, List<NodeGatewayMetaState> nodes)
         }
     }
 
+    /**
+     * The node request.
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
         NodeRequest() {}
 
@@ -156,6 +176,11 @@ public static class NodeRequest extends BaseNodeRequest {
         }
     }
 
+    /**
+     * The node gateway metastate.
+     *
+     * @opensearch.internal
+     */
     public static class NodeGatewayMetaState extends BaseNodeResponse {
 
         private Metadata metadata;
diff --git a/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayStartedShards.java b/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayStartedShards.java
index 413bf0e23090d..d05067b53173f 100644
--- a/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayStartedShards.java
+++ b/server/src/main/java/org/opensearch/gateway/TransportNodesListGatewayStartedShards.java
@@ -35,7 +35,7 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
+import org.opensearch.Version;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
@@ -50,17 +50,20 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.shard.ShardStateMetadata;
 import org.opensearch.index.store.Store;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -72,6 +75,8 @@
  * This transport action is used to fetch the shard version from each node during primary allocation in {@link GatewayAllocator}.
  * We use this to find out which node holds the latest shard version and which of them used to be a primary in order to allocate
  * shards after node or cluster restarts.
+ *
+ * @opensearch.internal
  */
 public class TransportNodesListGatewayStartedShards extends TransportNodesAction<
     TransportNodesListGatewayStartedShards.Request,
@@ -154,7 +159,8 @@ protected NodeGatewayStartedShards nodeOperation(NodeRequest request) {
                 nodeEnv.availableShardPaths(request.shardId)
             );
             if (shardStateMetadata != null) {
-                if (indicesService.getShardOrNull(shardId) == null) {
+                if (indicesService.getShardOrNull(shardId) == null
+                    && shardStateMetadata.indexDataLocation == ShardStateMetadata.IndexDataLocation.LOCAL) {
                     final String customDataPath;
                     if (request.getCustomDataPath() != null) {
                         customDataPath = request.getCustomDataPath();
@@ -193,6 +199,7 @@ protected NodeGatewayStartedShards nodeOperation(NodeRequest request) {
                             clusterService.localNode(),
                             allocationId,
                             shardStateMetadata.primary,
+                            null,
                             exception
                         );
                     }
@@ -200,15 +207,26 @@ protected NodeGatewayStartedShards nodeOperation(NodeRequest request) {
 
                 logger.debug("{} shard state info found: [{}]", shardId, shardStateMetadata);
                 String allocationId = shardStateMetadata.allocationId != null ? shardStateMetadata.allocationId.getId() : null;
-                return new NodeGatewayStartedShards(clusterService.localNode(), allocationId, shardStateMetadata.primary);
+                final IndexShard shard = indicesService.getShardOrNull(shardId);
+                return new NodeGatewayStartedShards(
+                    clusterService.localNode(),
+                    allocationId,
+                    shardStateMetadata.primary,
+                    shard != null ? shard.getLatestReplicationCheckpoint() : null
+                );
             }
             logger.trace("{} no local shard info found", shardId);
-            return new NodeGatewayStartedShards(clusterService.localNode(), null, false);
+            return new NodeGatewayStartedShards(clusterService.localNode(), null, false, null);
         } catch (Exception e) {
             throw new OpenSearchException("failed to load started shards", e);
         }
     }
 
+    /**
+     * The nodes request.
+     *
+     * @opensearch.internal
+     */
     public static class Request extends BaseNodesRequest<Request> {
 
         private final ShardId shardId;
@@ -255,6 +273,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     *  The nodes response.
+     *
+     * @opensearch.internal
+     */
     public static class NodesGatewayStartedShards extends BaseNodesResponse<NodeGatewayStartedShards> {
 
         public NodesGatewayStartedShards(StreamInput in) throws IOException {
@@ -280,6 +303,11 @@ protected void writeNodesTo(StreamOutput out, List<NodeGatewayStartedShards> nod
         }
     }
 
+    /**
+     * The request.
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
 
         private final ShardId shardId;
@@ -326,11 +354,16 @@ public String getCustomDataPath() {
         }
     }
 
+    /**
+     * The response.
+     *
+     * @opensearch.internal
+     */
     public static class NodeGatewayStartedShards extends BaseNodeResponse {
-
         private final String allocationId;
         private final boolean primary;
         private final Exception storeException;
+        private final ReplicationCheckpoint replicationCheckpoint;
 
         public NodeGatewayStartedShards(StreamInput in) throws IOException {
             super(in);
@@ -341,16 +374,33 @@ public NodeGatewayStartedShards(StreamInput in) throws IOException {
             } else {
                 storeException = null;
             }
+            if (in.getVersion().onOrAfter(Version.V_2_3_0) && in.readBoolean()) {
+                replicationCheckpoint = new ReplicationCheckpoint(in);
+            } else {
+                replicationCheckpoint = null;
+            }
         }
 
-        public NodeGatewayStartedShards(DiscoveryNode node, String allocationId, boolean primary) {
-            this(node, allocationId, primary, null);
+        public NodeGatewayStartedShards(
+            DiscoveryNode node,
+            String allocationId,
+            boolean primary,
+            ReplicationCheckpoint replicationCheckpoint
+        ) {
+            this(node, allocationId, primary, replicationCheckpoint, null);
         }
 
-        public NodeGatewayStartedShards(DiscoveryNode node, String allocationId, boolean primary, Exception storeException) {
+        public NodeGatewayStartedShards(
+            DiscoveryNode node,
+            String allocationId,
+            boolean primary,
+            ReplicationCheckpoint replicationCheckpoint,
+            Exception storeException
+        ) {
             super(node);
             this.allocationId = allocationId;
             this.primary = primary;
+            this.replicationCheckpoint = replicationCheckpoint;
             this.storeException = storeException;
         }
 
@@ -362,6 +412,10 @@ public boolean primary() {
             return this.primary;
         }
 
+        public ReplicationCheckpoint replicationCheckpoint() {
+            return this.replicationCheckpoint;
+        }
+
         public Exception storeException() {
             return this.storeException;
         }
@@ -377,6 +431,14 @@ public void writeTo(StreamOutput out) throws IOException {
             } else {
                 out.writeBoolean(false);
             }
+            if (out.getVersion().onOrAfter(Version.V_2_3_0)) {
+                if (replicationCheckpoint != null) {
+                    out.writeBoolean(true);
+                    replicationCheckpoint.writeTo(out);
+                } else {
+                    out.writeBoolean(false);
+                }
+            }
         }
 
         @Override
@@ -392,7 +454,8 @@ public boolean equals(Object o) {
 
             return primary == that.primary
                 && Objects.equals(allocationId, that.allocationId)
-                && Objects.equals(storeException, that.storeException);
+                && Objects.equals(storeException, that.storeException)
+                && Objects.equals(replicationCheckpoint, that.replicationCheckpoint);
         }
 
         @Override
@@ -400,6 +463,7 @@ public int hashCode() {
             int result = (allocationId != null ? allocationId.hashCode() : 0);
             result = 31 * result + (primary ? 1 : 0);
             result = 31 * result + (storeException != null ? storeException.hashCode() : 0);
+            result = 31 * result + (replicationCheckpoint != null ? replicationCheckpoint.hashCode() : 0);
             return result;
         }
 
@@ -410,6 +474,9 @@ public String toString() {
             if (storeException != null) {
                 buf.append(",storeException=").append(storeException);
             }
+            if (replicationCheckpoint != null) {
+                buf.append(",ReplicationCheckpoint=").append(replicationCheckpoint.toString());
+            }
             buf.append("]");
             return buf.toString();
         }
diff --git a/server/src/main/java/org/opensearch/gateway/WriteStateException.java b/server/src/main/java/org/opensearch/gateway/WriteStateException.java
index 11614397be5e5..e60eb0c11310d 100644
--- a/server/src/main/java/org/opensearch/gateway/WriteStateException.java
+++ b/server/src/main/java/org/opensearch/gateway/WriteStateException.java
@@ -37,6 +37,8 @@
 
 /**
  * This exception is thrown when there is a problem of writing state to disk.
+ *
+ * @opensearch.internal
  */
 public class WriteStateException extends IOException {
     private final boolean dirty;
diff --git a/server/src/main/java/org/opensearch/gateway/package-info.java b/server/src/main/java/org/opensearch/gateway/package-info.java
new file mode 100644
index 0000000000000..e89db75e04023
--- /dev/null
+++ b/server/src/main/java/org/opensearch/gateway/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Gateway Foundation Classes. */
+package org.opensearch.gateway;
diff --git a/server/src/main/java/org/opensearch/gateway/remote/ClusterMetadataManifest.java b/server/src/main/java/org/opensearch/gateway/remote/ClusterMetadataManifest.java
new file mode 100644
index 0000000000000..40b16f3d6323b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/gateway/remote/ClusterMetadataManifest.java
@@ -0,0 +1,514 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gateway.remote;
+
+import org.opensearch.Version;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Manifest file which contains the details of the uploaded entity metadata
+ *
+ * @opensearch.internal
+ */
+public class ClusterMetadataManifest implements Writeable, ToXContentFragment {
+
+    private static final ParseField CLUSTER_TERM_FIELD = new ParseField("cluster_term");
+    private static final ParseField STATE_VERSION_FIELD = new ParseField("state_version");
+    private static final ParseField CLUSTER_UUID_FIELD = new ParseField("cluster_uuid");
+    private static final ParseField STATE_UUID_FIELD = new ParseField("state_uuid");
+    private static final ParseField OPENSEARCH_VERSION_FIELD = new ParseField("opensearch_version");
+    private static final ParseField NODE_ID_FIELD = new ParseField("node_id");
+    private static final ParseField COMMITTED_FIELD = new ParseField("committed");
+    private static final ParseField INDICES_FIELD = new ParseField("indices");
+    private static final ParseField PREVIOUS_CLUSTER_UUID = new ParseField("previous_cluster_uuid");
+    private static final ParseField CLUSTER_UUID_COMMITTED = new ParseField("cluster_uuid_committed");
+
+    private static long term(Object[] fields) {
+        return (long) fields[0];
+    }
+
+    private static long version(Object[] fields) {
+        return (long) fields[1];
+    }
+
+    private static String clusterUUID(Object[] fields) {
+        return (String) fields[2];
+    }
+
+    private static String stateUUID(Object[] fields) {
+        return (String) fields[3];
+    }
+
+    private static Version opensearchVersion(Object[] fields) {
+        return Version.fromId((int) fields[4]);
+    }
+
+    private static String nodeId(Object[] fields) {
+        return (String) fields[5];
+    }
+
+    private static boolean committed(Object[] fields) {
+        return (boolean) fields[6];
+    }
+
+    private static List<UploadedIndexMetadata> indices(Object[] fields) {
+        return (List<UploadedIndexMetadata>) fields[7];
+    }
+
+    private static String previousClusterUUID(Object[] fields) {
+        return (String) fields[8];
+    }
+
+    private static boolean clusterUUIDCommitted(Object[] fields) {
+        return (boolean) fields[9];
+    }
+
+    private static final ConstructingObjectParser<ClusterMetadataManifest, Void> PARSER = new ConstructingObjectParser<>(
+        "cluster_metadata_manifest",
+        fields -> new ClusterMetadataManifest(
+            term(fields),
+            version(fields),
+            clusterUUID(fields),
+            stateUUID(fields),
+            opensearchVersion(fields),
+            nodeId(fields),
+            committed(fields),
+            indices(fields),
+            previousClusterUUID(fields),
+            clusterUUIDCommitted(fields)
+        )
+    );
+
+    static {
+        PARSER.declareLong(ConstructingObjectParser.constructorArg(), CLUSTER_TERM_FIELD);
+        PARSER.declareLong(ConstructingObjectParser.constructorArg(), STATE_VERSION_FIELD);
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), CLUSTER_UUID_FIELD);
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), STATE_UUID_FIELD);
+        PARSER.declareInt(ConstructingObjectParser.constructorArg(), OPENSEARCH_VERSION_FIELD);
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), NODE_ID_FIELD);
+        PARSER.declareBoolean(ConstructingObjectParser.constructorArg(), COMMITTED_FIELD);
+        PARSER.declareObjectArray(
+            ConstructingObjectParser.constructorArg(),
+            (p, c) -> UploadedIndexMetadata.fromXContent(p),
+            INDICES_FIELD
+        );
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), PREVIOUS_CLUSTER_UUID);
+        PARSER.declareBoolean(ConstructingObjectParser.constructorArg(), CLUSTER_UUID_COMMITTED);
+    }
+
+    private final List<UploadedIndexMetadata> indices;
+    private final long clusterTerm;
+    private final long stateVersion;
+    private final String clusterUUID;
+    private final String stateUUID;
+    private final Version opensearchVersion;
+    private final String nodeId;
+    private final boolean committed;
+    private final String previousClusterUUID;
+    private final boolean clusterUUIDCommitted;
+
+    public List<UploadedIndexMetadata> getIndices() {
+        return indices;
+    }
+
+    public long getClusterTerm() {
+        return clusterTerm;
+    }
+
+    public long getStateVersion() {
+        return stateVersion;
+    }
+
+    public String getClusterUUID() {
+        return clusterUUID;
+    }
+
+    public String getStateUUID() {
+        return stateUUID;
+    }
+
+    public Version getOpensearchVersion() {
+        return opensearchVersion;
+    }
+
+    public String getNodeId() {
+        return nodeId;
+    }
+
+    public boolean isCommitted() {
+        return committed;
+    }
+
+    public String getPreviousClusterUUID() {
+        return previousClusterUUID;
+    }
+
+    public boolean isClusterUUIDCommitted() {
+        return clusterUUIDCommitted;
+    }
+
+    public ClusterMetadataManifest(
+        long clusterTerm,
+        long version,
+        String clusterUUID,
+        String stateUUID,
+        Version opensearchVersion,
+        String nodeId,
+        boolean committed,
+        List<UploadedIndexMetadata> indices,
+        String previousClusterUUID,
+        boolean clusterUUIDCommitted
+    ) {
+        this.clusterTerm = clusterTerm;
+        this.stateVersion = version;
+        this.clusterUUID = clusterUUID;
+        this.stateUUID = stateUUID;
+        this.opensearchVersion = opensearchVersion;
+        this.nodeId = nodeId;
+        this.committed = committed;
+        this.indices = Collections.unmodifiableList(indices);
+        this.previousClusterUUID = previousClusterUUID;
+        this.clusterUUIDCommitted = clusterUUIDCommitted;
+    }
+
+    public ClusterMetadataManifest(StreamInput in) throws IOException {
+        this.clusterTerm = in.readVLong();
+        this.stateVersion = in.readVLong();
+        this.clusterUUID = in.readString();
+        this.stateUUID = in.readString();
+        this.opensearchVersion = Version.fromId(in.readInt());
+        this.nodeId = in.readString();
+        this.committed = in.readBoolean();
+        this.indices = Collections.unmodifiableList(in.readList(UploadedIndexMetadata::new));
+        this.previousClusterUUID = in.readString();
+        this.clusterUUIDCommitted = in.readBoolean();
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static Builder builder(ClusterMetadataManifest manifest) {
+        return new Builder(manifest);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(CLUSTER_TERM_FIELD.getPreferredName(), getClusterTerm())
+            .field(STATE_VERSION_FIELD.getPreferredName(), getStateVersion())
+            .field(CLUSTER_UUID_FIELD.getPreferredName(), getClusterUUID())
+            .field(STATE_UUID_FIELD.getPreferredName(), getStateUUID())
+            .field(OPENSEARCH_VERSION_FIELD.getPreferredName(), getOpensearchVersion().id)
+            .field(NODE_ID_FIELD.getPreferredName(), getNodeId())
+            .field(COMMITTED_FIELD.getPreferredName(), isCommitted());
+        builder.startArray(INDICES_FIELD.getPreferredName());
+        {
+            for (UploadedIndexMetadata uploadedIndexMetadata : indices) {
+                uploadedIndexMetadata.toXContent(builder, params);
+            }
+        }
+        builder.endArray();
+        builder.field(PREVIOUS_CLUSTER_UUID.getPreferredName(), getPreviousClusterUUID());
+        builder.field(CLUSTER_UUID_COMMITTED.getPreferredName(), isClusterUUIDCommitted());
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(clusterTerm);
+        out.writeVLong(stateVersion);
+        out.writeString(clusterUUID);
+        out.writeString(stateUUID);
+        out.writeInt(opensearchVersion.id);
+        out.writeString(nodeId);
+        out.writeBoolean(committed);
+        out.writeCollection(indices);
+        out.writeString(previousClusterUUID);
+        out.writeBoolean(clusterUUIDCommitted);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        final ClusterMetadataManifest that = (ClusterMetadataManifest) o;
+        return Objects.equals(indices, that.indices)
+            && clusterTerm == that.clusterTerm
+            && stateVersion == that.stateVersion
+            && Objects.equals(clusterUUID, that.clusterUUID)
+            && Objects.equals(stateUUID, that.stateUUID)
+            && Objects.equals(opensearchVersion, that.opensearchVersion)
+            && Objects.equals(nodeId, that.nodeId)
+            && Objects.equals(committed, that.committed)
+            && Objects.equals(previousClusterUUID, that.previousClusterUUID)
+            && Objects.equals(clusterUUIDCommitted, that.clusterUUIDCommitted);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(
+            indices,
+            clusterTerm,
+            stateVersion,
+            clusterUUID,
+            stateUUID,
+            opensearchVersion,
+            nodeId,
+            committed,
+            previousClusterUUID,
+            clusterUUIDCommitted
+        );
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    public static ClusterMetadataManifest fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+    /**
+     * Builder for ClusterMetadataManifest
+     *
+     * @opensearch.internal
+     */
+    public static class Builder {
+
+        private List<UploadedIndexMetadata> indices;
+        private long clusterTerm;
+        private long stateVersion;
+        private String clusterUUID;
+        private String stateUUID;
+        private Version opensearchVersion;
+        private String nodeId;
+        private String previousClusterUUID;
+        private boolean committed;
+        private boolean clusterUUIDCommitted;
+
+        public Builder indices(List<UploadedIndexMetadata> indices) {
+            this.indices = indices;
+            return this;
+        }
+
+        public Builder clusterTerm(long clusterTerm) {
+            this.clusterTerm = clusterTerm;
+            return this;
+        }
+
+        public Builder stateVersion(long stateVersion) {
+            this.stateVersion = stateVersion;
+            return this;
+        }
+
+        public Builder clusterUUID(String clusterUUID) {
+            this.clusterUUID = clusterUUID;
+            return this;
+        }
+
+        public Builder stateUUID(String stateUUID) {
+            this.stateUUID = stateUUID;
+            return this;
+        }
+
+        public Builder opensearchVersion(Version opensearchVersion) {
+            this.opensearchVersion = opensearchVersion;
+            return this;
+        }
+
+        public Builder nodeId(String nodeId) {
+            this.nodeId = nodeId;
+            return this;
+        }
+
+        public Builder committed(boolean committed) {
+            this.committed = committed;
+            return this;
+        }
+
+        public List<UploadedIndexMetadata> getIndices() {
+            return indices;
+        }
+
+        public Builder previousClusterUUID(String previousClusterUUID) {
+            this.previousClusterUUID = previousClusterUUID;
+            return this;
+        }
+
+        public Builder clusterUUIDCommitted(boolean clusterUUIDCommitted) {
+            this.clusterUUIDCommitted = clusterUUIDCommitted;
+            return this;
+        }
+
+        public Builder() {
+            indices = new ArrayList<>();
+        }
+
+        public Builder(ClusterMetadataManifest manifest) {
+            this.clusterTerm = manifest.clusterTerm;
+            this.stateVersion = manifest.stateVersion;
+            this.clusterUUID = manifest.clusterUUID;
+            this.stateUUID = manifest.stateUUID;
+            this.opensearchVersion = manifest.opensearchVersion;
+            this.nodeId = manifest.nodeId;
+            this.committed = manifest.committed;
+            this.indices = new ArrayList<>(manifest.indices);
+            this.previousClusterUUID = manifest.previousClusterUUID;
+            this.clusterUUIDCommitted = manifest.clusterUUIDCommitted;
+        }
+
+        public ClusterMetadataManifest build() {
+            return new ClusterMetadataManifest(
+                clusterTerm,
+                stateVersion,
+                clusterUUID,
+                stateUUID,
+                opensearchVersion,
+                nodeId,
+                committed,
+                indices,
+                previousClusterUUID,
+                clusterUUIDCommitted
+            );
+        }
+
+    }
+
+    /**
+     * Metadata for uploaded index metadata
+     *
+     * @opensearch.internal
+     */
+    public static class UploadedIndexMetadata implements Writeable, ToXContentFragment {
+
+        private static final ParseField INDEX_NAME_FIELD = new ParseField("index_name");
+        private static final ParseField INDEX_UUID_FIELD = new ParseField("index_uuid");
+        private static final ParseField UPLOADED_FILENAME_FIELD = new ParseField("uploaded_filename");
+
+        private static String indexName(Object[] fields) {
+            return (String) fields[0];
+        }
+
+        private static String indexUUID(Object[] fields) {
+            return (String) fields[1];
+        }
+
+        private static String uploadedFilename(Object[] fields) {
+            return (String) fields[2];
+        }
+
+        private static final ConstructingObjectParser<UploadedIndexMetadata, Void> PARSER = new ConstructingObjectParser<>(
+            "uploaded_index_metadata",
+            fields -> new UploadedIndexMetadata(indexName(fields), indexUUID(fields), uploadedFilename(fields))
+        );
+
+        static {
+            PARSER.declareString(ConstructingObjectParser.constructorArg(), INDEX_NAME_FIELD);
+            PARSER.declareString(ConstructingObjectParser.constructorArg(), INDEX_UUID_FIELD);
+            PARSER.declareString(ConstructingObjectParser.constructorArg(), UPLOADED_FILENAME_FIELD);
+        }
+
+        private final String indexName;
+        private final String indexUUID;
+        private final String uploadedFilename;
+
+        public UploadedIndexMetadata(String indexName, String indexUUID, String uploadedFileName) {
+            this.indexName = indexName;
+            this.indexUUID = indexUUID;
+            this.uploadedFilename = uploadedFileName;
+        }
+
+        public UploadedIndexMetadata(StreamInput in) throws IOException {
+            this.indexName = in.readString();
+            this.indexUUID = in.readString();
+            this.uploadedFilename = in.readString();
+        }
+
+        public String getUploadedFilePath() {
+            return uploadedFilename;
+        }
+
+        public String getUploadedFilename() {
+            String[] splitPath = uploadedFilename.split("/");
+            return splitPath[splitPath.length - 1];
+        }
+
+        public String getIndexName() {
+            return indexName;
+        }
+
+        public String getIndexUUID() {
+            return indexUUID;
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.startObject()
+                .field(INDEX_NAME_FIELD.getPreferredName(), getIndexName())
+                .field(INDEX_UUID_FIELD.getPreferredName(), getIndexUUID())
+                .field(UPLOADED_FILENAME_FIELD.getPreferredName(), getUploadedFilePath())
+                .endObject();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(indexName);
+            out.writeString(indexUUID);
+            out.writeString(uploadedFilename);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            final UploadedIndexMetadata that = (UploadedIndexMetadata) o;
+            return Objects.equals(indexName, that.indexName)
+                && Objects.equals(indexUUID, that.indexUUID)
+                && Objects.equals(uploadedFilename, that.uploadedFilename);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(indexName, indexUUID, uploadedFilename);
+        }
+
+        @Override
+        public String toString() {
+            return Strings.toString(MediaTypeRegistry.JSON, this);
+        }
+
+        public static UploadedIndexMetadata fromXContent(XContentParser parser) throws IOException {
+            return PARSER.parse(parser, null);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/gateway/remote/RemoteClusterStateService.java b/server/src/main/java/org/opensearch/gateway/remote/RemoteClusterStateService.java
new file mode 100644
index 0000000000000..164611816e1dc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/gateway/remote/RemoteClusterStateService.java
@@ -0,0 +1,968 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gateway.remote;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.Version;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedIndexMetadata;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.index.translog.transfer.BlobStoreTransferService;
+import org.opensearch.node.Node;
+import org.opensearch.node.remotestore.RemoteStoreNodeAttribute;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.blobstore.ChecksumBlobStoreFormat;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Function;
+import java.util.function.LongSupplier;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+
+import static org.opensearch.gateway.PersistedClusterStateService.SLOW_WRITE_LOGGING_THRESHOLD;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreClusterStateEnabled;
+
+/**
+ * A Service which provides APIs to upload and download cluster metadata from remote store.
+ *
+ * @opensearch.internal
+ */
+public class RemoteClusterStateService implements Closeable {
+
+    public static final String METADATA_NAME_FORMAT = "%s.dat";
+
+    public static final String METADATA_MANIFEST_NAME_FORMAT = "%s";
+
+    public static final int RETAINED_MANIFESTS = 10;
+
+    public static final String DELIMITER = "__";
+
+    private static final Logger logger = LogManager.getLogger(RemoteClusterStateService.class);
+
+    public static final int INDEX_METADATA_UPLOAD_WAIT_MILLIS = 20000;
+
+    public static final ChecksumBlobStoreFormat<IndexMetadata> INDEX_METADATA_FORMAT = new ChecksumBlobStoreFormat<>(
+        "index-metadata",
+        METADATA_NAME_FORMAT,
+        IndexMetadata::fromXContent
+    );
+
+    public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT = new ChecksumBlobStoreFormat<>(
+        "cluster-metadata-manifest",
+        METADATA_MANIFEST_NAME_FORMAT,
+        ClusterMetadataManifest::fromXContent
+    );
+    /**
+     * Used to specify if cluster state metadata should be published to remote store
+     */
+    public static final Setting<Boolean> REMOTE_CLUSTER_STATE_ENABLED_SETTING = Setting.boolSetting(
+        "cluster.remote_store.state.enabled",
+        false,
+        Property.NodeScope,
+        Property.Final
+    );
+
+    public static final String CLUSTER_STATE_PATH_TOKEN = "cluster-state";
+    public static final String INDEX_PATH_TOKEN = "index";
+    public static final String MANIFEST_PATH_TOKEN = "manifest";
+    public static final String MANIFEST_FILE_PREFIX = "manifest";
+    public static final String INDEX_METADATA_FILE_PREFIX = "metadata";
+
+    private final String nodeId;
+    private final Supplier<RepositoriesService> repositoriesService;
+    private final Settings settings;
+    private final LongSupplier relativeTimeNanosSupplier;
+    private final ThreadPool threadpool;
+    private BlobStoreRepository blobStoreRepository;
+    private BlobStoreTransferService blobStoreTransferService;
+    private volatile TimeValue slowWriteLoggingThreshold;
+
+    private final AtomicBoolean deleteStaleMetadataRunning = new AtomicBoolean(false);
+
+    public RemoteClusterStateService(
+        String nodeId,
+        Supplier<RepositoriesService> repositoriesService,
+        Settings settings,
+        ClusterSettings clusterSettings,
+        LongSupplier relativeTimeNanosSupplier,
+        ThreadPool threadPool
+    ) {
+        assert isRemoteStoreClusterStateEnabled(settings) : "Remote cluster state is not enabled";
+        this.nodeId = nodeId;
+        this.repositoriesService = repositoriesService;
+        this.settings = settings;
+        this.relativeTimeNanosSupplier = relativeTimeNanosSupplier;
+        this.threadpool = threadPool;
+        this.slowWriteLoggingThreshold = clusterSettings.get(SLOW_WRITE_LOGGING_THRESHOLD);
+        clusterSettings.addSettingsUpdateConsumer(SLOW_WRITE_LOGGING_THRESHOLD, this::setSlowWriteLoggingThreshold);
+    }
+
+    private BlobStoreTransferService getBlobStoreTransferService() {
+        if (blobStoreTransferService == null) {
+            blobStoreTransferService = new BlobStoreTransferService(blobStoreRepository.blobStore(), threadpool);
+        }
+        return blobStoreTransferService;
+    }
+
+    /**
+     * This method uploads entire cluster state metadata to the configured blob store. For now only index metadata upload is supported. This method should be
+     * invoked by the elected cluster manager when the remote cluster state is enabled.
+     *
+     * @return A manifest object which contains the details of uploaded entity metadata.
+     */
+    @Nullable
+    public ClusterMetadataManifest writeFullMetadata(ClusterState clusterState, String previousClusterUUID) throws IOException {
+        final long startTimeNanos = relativeTimeNanosSupplier.getAsLong();
+        if (clusterState.nodes().isLocalNodeElectedClusterManager() == false) {
+            logger.error("Local node is not elected cluster manager. Exiting");
+            return null;
+        }
+
+        // any validations before/after upload ?
+        final List<UploadedIndexMetadata> allUploadedIndexMetadata = writeIndexMetadataParallel(
+            clusterState,
+            new ArrayList<>(clusterState.metadata().indices().values())
+        );
+        final ClusterMetadataManifest manifest = uploadManifest(clusterState, allUploadedIndexMetadata, previousClusterUUID, false);
+        final long durationMillis = TimeValue.nsecToMSec(relativeTimeNanosSupplier.getAsLong() - startTimeNanos);
+        if (durationMillis >= slowWriteLoggingThreshold.getMillis()) {
+            logger.warn(
+                "writing cluster state took [{}ms] which is above the warn threshold of [{}]; " + "wrote full state with [{}] indices",
+                durationMillis,
+                slowWriteLoggingThreshold,
+                allUploadedIndexMetadata.size()
+            );
+        } else {
+            // todo change to debug
+            logger.info(
+                "writing cluster state took [{}ms]; " + "wrote full state with [{}] indices",
+                durationMillis,
+                allUploadedIndexMetadata.size()
+            );
+        }
+        return manifest;
+    }
+
+    /**
+     * This method uploads the diff between the previous cluster state and the current cluster state. The previous manifest file is needed to create the new
+     * manifest. The new manifest file is created by using the unchanged metadata from the previous manifest and the new metadata changes from the current
+     * cluster state.
+     *
+     * @return The uploaded ClusterMetadataManifest file
+     */
+    @Nullable
+    public ClusterMetadataManifest writeIncrementalMetadata(
+        ClusterState previousClusterState,
+        ClusterState clusterState,
+        ClusterMetadataManifest previousManifest
+    ) throws IOException {
+        final long startTimeNanos = relativeTimeNanosSupplier.getAsLong();
+        if (clusterState.nodes().isLocalNodeElectedClusterManager() == false) {
+            logger.error("Local node is not elected cluster manager. Exiting");
+            return null;
+        }
+        assert previousClusterState.metadata().coordinationMetadata().term() == clusterState.metadata().coordinationMetadata().term();
+        final Map<String, Long> previousStateIndexMetadataVersionByName = new HashMap<>();
+        for (final IndexMetadata indexMetadata : previousClusterState.metadata().indices().values()) {
+            previousStateIndexMetadataVersionByName.put(indexMetadata.getIndex().getName(), indexMetadata.getVersion());
+        }
+
+        int numIndicesUpdated = 0;
+        int numIndicesUnchanged = 0;
+        final Map<String, ClusterMetadataManifest.UploadedIndexMetadata> allUploadedIndexMetadata = previousManifest.getIndices()
+            .stream()
+            .collect(Collectors.toMap(UploadedIndexMetadata::getIndexName, Function.identity()));
+
+        List<IndexMetadata> toUpload = new ArrayList<>();
+
+        for (final IndexMetadata indexMetadata : clusterState.metadata().indices().values()) {
+            final Long previousVersion = previousStateIndexMetadataVersionByName.get(indexMetadata.getIndex().getName());
+            if (previousVersion == null || indexMetadata.getVersion() != previousVersion) {
+                logger.trace(
+                    "updating metadata for [{}], changing version from [{}] to [{}]",
+                    indexMetadata.getIndex(),
+                    previousVersion,
+                    indexMetadata.getVersion()
+                );
+                numIndicesUpdated++;
+                toUpload.add(indexMetadata);
+            } else {
+                numIndicesUnchanged++;
+            }
+            previousStateIndexMetadataVersionByName.remove(indexMetadata.getIndex().getName());
+        }
+
+        List<UploadedIndexMetadata> uploadedIndexMetadataList = writeIndexMetadataParallel(clusterState, toUpload);
+        uploadedIndexMetadataList.forEach(
+            uploadedIndexMetadata -> allUploadedIndexMetadata.put(uploadedIndexMetadata.getIndexName(), uploadedIndexMetadata)
+        );
+
+        for (String removedIndexName : previousStateIndexMetadataVersionByName.keySet()) {
+            allUploadedIndexMetadata.remove(removedIndexName);
+        }
+        final ClusterMetadataManifest manifest = uploadManifest(
+            clusterState,
+            new ArrayList<>(allUploadedIndexMetadata.values()),
+            previousManifest.getPreviousClusterUUID(),
+            false
+        );
+        deleteStaleClusterMetadata(clusterState.getClusterName().value(), clusterState.metadata().clusterUUID(), RETAINED_MANIFESTS);
+
+        final long durationMillis = TimeValue.nsecToMSec(relativeTimeNanosSupplier.getAsLong() - startTimeNanos);
+        if (durationMillis >= slowWriteLoggingThreshold.getMillis()) {
+            logger.warn(
+                "writing cluster state took [{}ms] which is above the warn threshold of [{}]; "
+                    + "wrote  metadata for [{}] indices and skipped [{}] unchanged indices",
+                durationMillis,
+                slowWriteLoggingThreshold,
+                numIndicesUpdated,
+                numIndicesUnchanged
+            );
+        } else {
+            logger.trace(
+                "writing cluster state took [{}ms]; " + "wrote metadata for [{}] indices and skipped [{}] unchanged indices",
+                durationMillis,
+                numIndicesUpdated,
+                numIndicesUnchanged
+            );
+        }
+        return manifest;
+    }
+
+    /**
+     * Uploads provided IndexMetadata's to remote store in parallel. The call is blocking so the method waits for upload to finish and then return.
+     *
+     * @param clusterState current ClusterState
+     * @param toUpload list of IndexMetadata to upload
+     * @return {@code List<UploadedIndexMetadata>} list of IndexMetadata uploaded to remote
+     */
+    private List<UploadedIndexMetadata> writeIndexMetadataParallel(ClusterState clusterState, List<IndexMetadata> toUpload)
+        throws IOException {
+        List<Exception> exceptionList = Collections.synchronizedList(new ArrayList<>(toUpload.size()));
+        final CountDownLatch latch = new CountDownLatch(toUpload.size());
+        List<UploadedIndexMetadata> result = new ArrayList<>(toUpload.size());
+
+        LatchedActionListener<UploadedIndexMetadata> latchedActionListener = new LatchedActionListener<>(
+            ActionListener.wrap((UploadedIndexMetadata uploadedIndexMetadata) -> {
+                logger.trace(
+                    String.format(Locale.ROOT, "IndexMetadata uploaded successfully for %s", uploadedIndexMetadata.getIndexName())
+                );
+                result.add(uploadedIndexMetadata);
+            }, ex -> {
+                assert ex instanceof IndexMetadataTransferException;
+                logger.error(
+                    () -> new ParameterizedMessage("Exception during transfer of IndexMetadata to Remote {}", ex.getMessage()),
+                    ex
+                );
+                exceptionList.add(ex);
+            }),
+            latch
+        );
+
+        for (IndexMetadata indexMetadata : toUpload) {
+            // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/index/ftqsCnn9TgOX/metadata_4_1690947200
+            writeIndexMetadataAsync(clusterState, indexMetadata, latchedActionListener);
+        }
+
+        try {
+            if (latch.await(INDEX_METADATA_UPLOAD_WAIT_MILLIS, TimeUnit.MILLISECONDS) == false) {
+                IndexMetadataTransferException ex = new IndexMetadataTransferException(
+                    String.format(
+                        Locale.ROOT,
+                        "Timed out waiting for transfer of index metadata to complete - %s",
+                        toUpload.stream().map(IndexMetadata::getIndex).map(Index::toString).collect(Collectors.joining(""))
+                    )
+                );
+                exceptionList.forEach(ex::addSuppressed);
+                throw ex;
+            }
+        } catch (InterruptedException ex) {
+            exceptionList.forEach(ex::addSuppressed);
+            IndexMetadataTransferException exception = new IndexMetadataTransferException(
+                String.format(
+                    Locale.ROOT,
+                    "Timed out waiting for transfer of index metadata to complete - %s",
+                    toUpload.stream().map(IndexMetadata::getIndex).map(Index::toString).collect(Collectors.joining(""))
+                ),
+                ex
+            );
+            Thread.currentThread().interrupt();
+            throw exception;
+        }
+        if (exceptionList.size() > 0) {
+            IndexMetadataTransferException exception = new IndexMetadataTransferException(
+                String.format(
+                    Locale.ROOT,
+                    "Exception during transfer of IndexMetadata to Remote %s",
+                    toUpload.stream().map(IndexMetadata::getIndex).map(Index::toString).collect(Collectors.joining(""))
+                )
+            );
+            exceptionList.forEach(exception::addSuppressed);
+            throw exception;
+        }
+        return result;
+    }
+
+    /**
+     * Allows async Upload of IndexMetadata to remote
+     *
+     * @param clusterState current ClusterState
+     * @param indexMetadata {@link IndexMetadata} to upload
+     * @param latchedActionListener listener to respond back on after upload finishes
+     */
+    private void writeIndexMetadataAsync(
+        ClusterState clusterState,
+        IndexMetadata indexMetadata,
+        LatchedActionListener<UploadedIndexMetadata> latchedActionListener
+    ) throws IOException {
+        final BlobContainer indexMetadataContainer = indexMetadataContainer(
+            clusterState.getClusterName().value(),
+            clusterState.metadata().clusterUUID(),
+            indexMetadata.getIndexUUID()
+        );
+        final String indexMetadataFilename = indexMetadataFileName(indexMetadata);
+        ActionListener<Void> completionListener = ActionListener.wrap(
+            resp -> latchedActionListener.onResponse(
+                new UploadedIndexMetadata(
+                    indexMetadata.getIndex().getName(),
+                    indexMetadata.getIndexUUID(),
+                    indexMetadataContainer.path().buildAsString() + indexMetadataFilename
+                )
+            ),
+            ex -> latchedActionListener.onFailure(new IndexMetadataTransferException(indexMetadata.getIndex().toString(), ex))
+        );
+
+        INDEX_METADATA_FORMAT.writeAsync(
+            indexMetadata,
+            indexMetadataContainer,
+            indexMetadataFilename,
+            blobStoreRepository.getCompressor(),
+            completionListener
+        );
+    }
+
+    @Nullable
+    public ClusterMetadataManifest markLastStateAsCommitted(ClusterState clusterState, ClusterMetadataManifest previousManifest)
+        throws IOException {
+        assert clusterState != null : "Last accepted cluster state is not set";
+        if (clusterState.nodes().isLocalNodeElectedClusterManager() == false) {
+            logger.error("Local node is not elected cluster manager. Exiting");
+            return null;
+        }
+        assert previousManifest != null : "Last cluster metadata manifest is not set";
+        ClusterMetadataManifest committedManifest = uploadManifest(
+            clusterState,
+            previousManifest.getIndices(),
+            previousManifest.getPreviousClusterUUID(),
+            true
+        );
+        deleteStaleClusterUUIDs(clusterState, committedManifest);
+        return committedManifest;
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (blobStoreRepository != null) {
+            IOUtils.close(blobStoreRepository);
+        }
+    }
+
+    public void start() {
+        assert isRemoteStoreClusterStateEnabled(settings) == true : "Remote cluster state is not enabled";
+        final String remoteStoreRepo = settings.get(
+            Node.NODE_ATTRIBUTES.getKey() + RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY
+        );
+        assert remoteStoreRepo != null : "Remote Cluster State repository is not configured";
+        final Repository repository = repositoriesService.get().repository(remoteStoreRepo);
+        assert repository instanceof BlobStoreRepository : "Repository should be instance of BlobStoreRepository";
+        blobStoreRepository = (BlobStoreRepository) repository;
+    }
+
+    private ClusterMetadataManifest uploadManifest(
+        ClusterState clusterState,
+        List<UploadedIndexMetadata> uploadedIndexMetadata,
+        String previousClusterUUID,
+        boolean committed
+    ) throws IOException {
+        synchronized (this) {
+            final String manifestFileName = getManifestFileName(clusterState.term(), clusterState.version());
+            final ClusterMetadataManifest manifest = new ClusterMetadataManifest(
+                clusterState.term(),
+                clusterState.getVersion(),
+                clusterState.metadata().clusterUUID(),
+                clusterState.stateUUID(),
+                Version.CURRENT,
+                nodeId,
+                committed,
+                uploadedIndexMetadata,
+                previousClusterUUID,
+                clusterState.metadata().clusterUUIDCommitted()
+            );
+            writeMetadataManifest(clusterState.getClusterName().value(), clusterState.metadata().clusterUUID(), manifest, manifestFileName);
+            return manifest;
+        }
+    }
+
+    private void writeMetadataManifest(String clusterName, String clusterUUID, ClusterMetadataManifest uploadManifest, String fileName)
+        throws IOException {
+        final BlobContainer metadataManifestContainer = manifestContainer(clusterName, clusterUUID);
+        CLUSTER_METADATA_MANIFEST_FORMAT.write(uploadManifest, metadataManifestContainer, fileName, blobStoreRepository.getCompressor());
+    }
+
+    private String fetchPreviousClusterUUID(String clusterName, String clusterUUID) {
+        final Optional<ClusterMetadataManifest> latestManifest = getLatestClusterMetadataManifest(clusterName, clusterUUID);
+        if (!latestManifest.isPresent()) {
+            final String previousClusterUUID = getLastKnownUUIDFromRemote(clusterName);
+            assert !clusterUUID.equals(previousClusterUUID) : "Last cluster UUID is same current cluster UUID";
+            return previousClusterUUID;
+        }
+        return latestManifest.get().getPreviousClusterUUID();
+    }
+
+    private BlobContainer indexMetadataContainer(String clusterName, String clusterUUID, String indexUUID) {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/index/ftqsCnn9TgOX
+        return blobStoreRepository.blobStore()
+            .blobContainer(getCusterMetadataBasePath(clusterName, clusterUUID).add(INDEX_PATH_TOKEN).add(indexUUID));
+    }
+
+    private BlobContainer manifestContainer(String clusterName, String clusterUUID) {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/manifest
+        return blobStoreRepository.blobStore().blobContainer(getManifestFolderPath(clusterName, clusterUUID));
+    }
+
+    private BlobPath getCusterMetadataBasePath(String clusterName, String clusterUUID) {
+        return blobStoreRepository.basePath().add(encodeString(clusterName)).add(CLUSTER_STATE_PATH_TOKEN).add(clusterUUID);
+    }
+
+    private BlobContainer clusterUUIDContainer(String clusterName) {
+        return blobStoreRepository.blobStore()
+            .blobContainer(
+                blobStoreRepository.basePath()
+                    .add(Base64.getUrlEncoder().withoutPadding().encodeToString(clusterName.getBytes(StandardCharsets.UTF_8)))
+                    .add(CLUSTER_STATE_PATH_TOKEN)
+            );
+    }
+
+    private void setSlowWriteLoggingThreshold(TimeValue slowWriteLoggingThreshold) {
+        this.slowWriteLoggingThreshold = slowWriteLoggingThreshold;
+    }
+
+    private static String getManifestFileName(long term, long version) {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/manifest/manifest_2147483642_2147483637_456536447
+        return String.join(DELIMITER, getManifestFileNamePrefix(term, version), RemoteStoreUtils.invertLong(System.currentTimeMillis()));
+    }
+
+    private static String getManifestFileNamePrefix(long term, long version) {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/manifest/manifest_2147483642_2147483637
+        return String.join(DELIMITER, MANIFEST_PATH_TOKEN, RemoteStoreUtils.invertLong(term), RemoteStoreUtils.invertLong(version));
+    }
+
+    private static String indexMetadataFileName(IndexMetadata indexMetadata) {
+        return String.join(
+            DELIMITER,
+            INDEX_METADATA_FILE_PREFIX,
+            String.valueOf(indexMetadata.getVersion()),
+            String.valueOf(System.currentTimeMillis())
+        );
+    }
+
+    private BlobPath getManifestFolderPath(String clusterName, String clusterUUID) {
+        return getCusterMetadataBasePath(clusterName, clusterUUID).add(MANIFEST_PATH_TOKEN);
+    }
+
+    /**
+     * Fetch latest index metadata from remote cluster state
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @return {@code Map<String, IndexMetadata>} latest IndexUUID to IndexMetadata map
+     */
+    public Map<String, IndexMetadata> getLatestIndexMetadata(String clusterName, String clusterUUID) throws IOException {
+        start();
+        Map<String, IndexMetadata> remoteIndexMetadata = new HashMap<>();
+        Optional<ClusterMetadataManifest> clusterMetadataManifest = getLatestClusterMetadataManifest(clusterName, clusterUUID);
+        if (!clusterMetadataManifest.isPresent()) {
+            throw new IllegalStateException("Latest index metadata is not present for the provided clusterUUID");
+        }
+        assert Objects.equals(clusterUUID, clusterMetadataManifest.get().getClusterUUID())
+            : "Corrupt ClusterMetadataManifest found. Cluster UUID mismatch.";
+        for (UploadedIndexMetadata uploadedIndexMetadata : clusterMetadataManifest.get().getIndices()) {
+            IndexMetadata indexMetadata = getIndexMetadata(clusterName, clusterUUID, uploadedIndexMetadata);
+            remoteIndexMetadata.put(uploadedIndexMetadata.getIndexUUID(), indexMetadata);
+        }
+        return remoteIndexMetadata;
+    }
+
+    /**
+     * Fetch index metadata from remote cluster state
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @param uploadedIndexMetadata {@link UploadedIndexMetadata} contains details about remote location of index metadata
+     * @return {@link IndexMetadata}
+     */
+    private IndexMetadata getIndexMetadata(String clusterName, String clusterUUID, UploadedIndexMetadata uploadedIndexMetadata) {
+        try {
+            String[] splitPath = uploadedIndexMetadata.getUploadedFilename().split("/");
+            return INDEX_METADATA_FORMAT.read(
+                indexMetadataContainer(clusterName, clusterUUID, uploadedIndexMetadata.getIndexUUID()),
+                splitPath[splitPath.length - 1],
+                blobStoreRepository.getNamedXContentRegistry()
+            );
+        } catch (IOException e) {
+            throw new IllegalStateException(
+                String.format(Locale.ROOT, "Error while downloading IndexMetadata - %s", uploadedIndexMetadata.getUploadedFilename()),
+                e
+            );
+        }
+    }
+
+    /**
+     * Fetch latest ClusterMetadataManifest from remote state store
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @return ClusterMetadataManifest
+     */
+    public Optional<ClusterMetadataManifest> getLatestClusterMetadataManifest(String clusterName, String clusterUUID) {
+        Optional<String> latestManifestFileName = getLatestManifestFileName(clusterName, clusterUUID);
+        if (latestManifestFileName.isPresent()) {
+            return Optional.of(fetchRemoteClusterMetadataManifest(clusterName, clusterUUID, latestManifestFileName.get()));
+        }
+        return Optional.empty();
+    }
+
+    /**
+     * Fetch the previous cluster UUIDs from remote state store and return the most recent valid cluster UUID
+     *
+     * @param clusterName The cluster name for which previous cluster UUID is to be fetched
+     * @return Last valid cluster UUID
+     */
+    public String getLastKnownUUIDFromRemote(String clusterName) {
+        try {
+            Set<String> clusterUUIDs = getAllClusterUUIDs(clusterName);
+            Map<String, ClusterMetadataManifest> latestManifests = getLatestManifestForAllClusterUUIDs(clusterName, clusterUUIDs);
+            List<String> validChain = createClusterChain(latestManifests, clusterName);
+            if (validChain.isEmpty()) {
+                return ClusterState.UNKNOWN_UUID;
+            }
+            return validChain.get(0);
+        } catch (IOException e) {
+            throw new IllegalStateException(
+                String.format(Locale.ROOT, "Error while fetching previous UUIDs from remote store for cluster name: %s", clusterName)
+            );
+        }
+    }
+
+    private Set<String> getAllClusterUUIDs(String clusterName) throws IOException {
+        Map<String, BlobContainer> clusterUUIDMetadata = clusterUUIDContainer(clusterName).children();
+        if (clusterUUIDMetadata == null) {
+            return Collections.emptySet();
+        }
+        return Collections.unmodifiableSet(clusterUUIDMetadata.keySet());
+    }
+
+    private Map<String, ClusterMetadataManifest> getLatestManifestForAllClusterUUIDs(String clusterName, Set<String> clusterUUIDs) {
+        Map<String, ClusterMetadataManifest> manifestsByClusterUUID = new HashMap<>();
+        for (String clusterUUID : clusterUUIDs) {
+            try {
+                Optional<ClusterMetadataManifest> manifest = getLatestClusterMetadataManifest(clusterName, clusterUUID);
+                manifest.ifPresent(clusterMetadataManifest -> manifestsByClusterUUID.put(clusterUUID, clusterMetadataManifest));
+            } catch (Exception e) {
+                throw new IllegalStateException(
+                    String.format(Locale.ROOT, "Exception in fetching manifest for clusterUUID: %s", clusterUUID)
+                );
+            }
+        }
+        return manifestsByClusterUUID;
+    }
+
+    /**
+     * This method creates a valid cluster UUID chain.
+     *
+     * @param manifestsByClusterUUID Map of latest ClusterMetadataManifest for every cluster UUID
+     * @return List of cluster UUIDs. The first element is the most recent cluster UUID in the chain
+     */
+    private List<String> createClusterChain(final Map<String, ClusterMetadataManifest> manifestsByClusterUUID, final String clusterName) {
+        final Map<String, String> clusterUUIDGraph = manifestsByClusterUUID.values()
+            .stream()
+            .collect(Collectors.toMap(ClusterMetadataManifest::getClusterUUID, ClusterMetadataManifest::getPreviousClusterUUID));
+        final List<String> validClusterUUIDs = manifestsByClusterUUID.values()
+            .stream()
+            .filter(m -> !isInvalidClusterUUID(m) && !clusterUUIDGraph.containsValue(m.getClusterUUID()))
+            .map(ClusterMetadataManifest::getClusterUUID)
+            .collect(Collectors.toList());
+        if (validClusterUUIDs.isEmpty()) {
+            logger.info("There is no valid previous cluster UUID");
+            return Collections.emptyList();
+        }
+        if (validClusterUUIDs.size() > 1) {
+            // If the valid cluster UUIDs are more that 1, it means there was some race condition where
+            // more then 2 cluster manager nodes tried to become active cluster manager and published
+            // 2 cluster UUIDs which followed the same previous UUID.
+            final Map<String, ClusterMetadataManifest> manifestsByClusterUUIDTrimmed = trimClusterUUIDs(
+                manifestsByClusterUUID,
+                validClusterUUIDs,
+                clusterName
+            );
+            if (manifestsByClusterUUID.size() == manifestsByClusterUUIDTrimmed.size()) {
+                throw new IllegalStateException(
+                    String.format(
+                        Locale.ROOT,
+                        "The system has ended into multiple valid cluster states in the remote store. "
+                            + "Please check their latest manifest to decide which one you want to keep. Valid Cluster UUIDs: - %s",
+                        validClusterUUIDs
+                    )
+                );
+            }
+            return createClusterChain(manifestsByClusterUUIDTrimmed, clusterName);
+        }
+        final List<String> validChain = new ArrayList<>();
+        String currentUUID = validClusterUUIDs.get(0);
+        while (currentUUID != null && !ClusterState.UNKNOWN_UUID.equals(currentUUID)) {
+            validChain.add(currentUUID);
+            // Getting the previous cluster UUID of a cluster UUID from the clusterUUID Graph
+            currentUUID = clusterUUIDGraph.get(currentUUID);
+        }
+        return validChain;
+    }
+
+    /**
+     * This method take a map of manifests for different cluster UUIDs and removes the
+     * manifest of a cluster UUID if the latest metadata for that cluster UUID is equivalent
+     * to the latest metadata of its previous UUID.
+     * @return Trimmed map of manifests
+     */
+    private Map<String, ClusterMetadataManifest> trimClusterUUIDs(
+        final Map<String, ClusterMetadataManifest> latestManifestsByClusterUUID,
+        final List<String> validClusterUUIDs,
+        final String clusterName
+    ) {
+        final Map<String, ClusterMetadataManifest> trimmedUUIDs = new HashMap<>(latestManifestsByClusterUUID);
+        for (String clusterUUID : validClusterUUIDs) {
+            ClusterMetadataManifest currentManifest = trimmedUUIDs.get(clusterUUID);
+            // Here we compare the manifest of current UUID to that of previous UUID
+            // In case currentUUID's latest manifest is same as previous UUIDs latest manifest,
+            // that means it was restored from previousUUID and no IndexMetadata update was performed on it.
+            if (ClusterState.UNKNOWN_UUID.equals(currentManifest.getPreviousClusterUUID())) {
+                if (currentManifest.getIndices().isEmpty()) {
+                    trimmedUUIDs.remove(clusterUUID);
+                }
+            } else {
+                ClusterMetadataManifest previousManifest = trimmedUUIDs.get(currentManifest.getPreviousClusterUUID());
+                if (isMetadataEqual(currentManifest, previousManifest, clusterName)) {
+                    trimmedUUIDs.remove(clusterUUID);
+                }
+            }
+        }
+        return trimmedUUIDs;
+    }
+
+    private boolean isMetadataEqual(ClusterMetadataManifest first, ClusterMetadataManifest second, String clusterName) {
+        // todo clusterName can be set as final in the constructor
+        if (first.getIndices().size() != second.getIndices().size()) {
+            return false;
+        }
+        final Map<String, UploadedIndexMetadata> secondIndices = second.getIndices()
+            .stream()
+            .collect(Collectors.toMap(md -> md.getIndexName(), Function.identity()));
+        for (UploadedIndexMetadata uploadedIndexMetadata : first.getIndices()) {
+            final IndexMetadata firstIndexMetadata = getIndexMetadata(clusterName, first.getClusterUUID(), uploadedIndexMetadata);
+            final UploadedIndexMetadata secondUploadedIndexMetadata = secondIndices.get(uploadedIndexMetadata.getIndexName());
+            if (secondUploadedIndexMetadata == null) {
+                return false;
+            }
+            final IndexMetadata secondIndexMetadata = getIndexMetadata(clusterName, second.getClusterUUID(), secondUploadedIndexMetadata);
+            if (firstIndexMetadata.equals(secondIndexMetadata) == false) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean isInvalidClusterUUID(ClusterMetadataManifest manifest) {
+        return !manifest.isClusterUUIDCommitted();
+    }
+
+    /**
+     * Fetch ClusterMetadataManifest files from remote state store in order
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @param limit max no of files to fetch
+     * @return all manifest file names
+     */
+    private List<BlobMetadata> getManifestFileNames(String clusterName, String clusterUUID, int limit) throws IllegalStateException {
+        try {
+            /**
+             * {@link BlobContainer#listBlobsByPrefixInSortedOrder} will list the latest manifest file first
+             * as the manifest file name generated via {@link RemoteClusterStateService#getManifestFileName} ensures
+             * when sorted in LEXICOGRAPHIC order the latest uploaded manifest file comes on top.
+             */
+            return manifestContainer(clusterName, clusterUUID).listBlobsByPrefixInSortedOrder(
+                MANIFEST_FILE_PREFIX + DELIMITER,
+                limit,
+                BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC
+            );
+        } catch (IOException e) {
+            throw new IllegalStateException("Error while fetching latest manifest file for remote cluster state", e);
+        }
+    }
+
+    /**
+     * Fetch latest ClusterMetadataManifest file from remote state store
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @return latest ClusterMetadataManifest filename
+     */
+    private Optional<String> getLatestManifestFileName(String clusterName, String clusterUUID) throws IllegalStateException {
+        List<BlobMetadata> manifestFilesMetadata = getManifestFileNames(clusterName, clusterUUID, 1);
+        if (manifestFilesMetadata != null && !manifestFilesMetadata.isEmpty()) {
+            return Optional.of(manifestFilesMetadata.get(0).name());
+        }
+        logger.info("No manifest file present in remote store for cluster name: {}, cluster UUID: {}", clusterName, clusterUUID);
+        return Optional.empty();
+    }
+
+    /**
+     * Fetch ClusterMetadataManifest from remote state store
+     *
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param clusterName name of the cluster
+     * @return ClusterMetadataManifest
+     */
+    private ClusterMetadataManifest fetchRemoteClusterMetadataManifest(String clusterName, String clusterUUID, String filename)
+        throws IllegalStateException {
+        try {
+            return RemoteClusterStateService.CLUSTER_METADATA_MANIFEST_FORMAT.read(
+                manifestContainer(clusterName, clusterUUID),
+                filename,
+                blobStoreRepository.getNamedXContentRegistry()
+            );
+        } catch (IOException e) {
+            throw new IllegalStateException(String.format(Locale.ROOT, "Error while downloading cluster metadata - %s", filename), e);
+        }
+    }
+
+    public static String encodeString(String content) {
+        return Base64.getUrlEncoder().withoutPadding().encodeToString(content.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /**
+     * Exception for IndexMetadata transfer failures to remote
+     */
+    static class IndexMetadataTransferException extends RuntimeException {
+
+        public IndexMetadataTransferException(String errorDesc) {
+            super(errorDesc);
+        }
+
+        public IndexMetadataTransferException(String errorDesc, Throwable cause) {
+            super(errorDesc, cause);
+        }
+    }
+
+    /**
+     * Purges all remote cluster state against provided cluster UUIDs
+     *
+     * @param clusterName name of the cluster
+     * @param clusterUUIDs clusteUUIDs for which the remote state needs to be purged
+     */
+    private void deleteStaleUUIDsClusterMetadata(String clusterName, List<String> clusterUUIDs) {
+        clusterUUIDs.forEach(clusterUUID -> {
+            getBlobStoreTransferService().deleteAsync(
+                ThreadPool.Names.REMOTE_PURGE,
+                getCusterMetadataBasePath(clusterName, clusterUUID),
+                new ActionListener<>() {
+                    @Override
+                    public void onResponse(Void unused) {
+                        logger.info("Deleted all remote cluster metadata for cluster UUID - {}", clusterUUID);
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        logger.error(
+                            new ParameterizedMessage(
+                                "Exception occurred while deleting all remote cluster metadata for cluster UUID {}",
+                                clusterUUID
+                            ),
+                            e
+                        );
+                    }
+                }
+            );
+        });
+    }
+
+    /**
+     * Deletes older than last {@code versionsToRetain} manifests. Also cleans up unreferenced IndexMetadata associated with older manifests
+     *
+     * @param clusterName name of the cluster
+     * @param clusterUUID uuid of cluster state to refer to in remote
+     * @param manifestsToRetain no of latest manifest files to keep in remote
+     */
+    private void deleteStaleClusterMetadata(String clusterName, String clusterUUID, int manifestsToRetain) {
+        if (deleteStaleMetadataRunning.compareAndSet(false, true) == false) {
+            logger.info("Delete stale cluster metadata task is already in progress.");
+            return;
+        }
+        try {
+            getBlobStoreTransferService().listAllInSortedOrderAsync(
+                ThreadPool.Names.REMOTE_PURGE,
+                getManifestFolderPath(clusterName, clusterUUID),
+                "manifest",
+                Integer.MAX_VALUE,
+                new ActionListener<>() {
+                    @Override
+                    public void onResponse(List<BlobMetadata> blobMetadata) {
+                        if (blobMetadata.size() > manifestsToRetain) {
+                            deleteClusterMetadata(
+                                clusterName,
+                                clusterUUID,
+                                blobMetadata.subList(0, manifestsToRetain - 1),
+                                blobMetadata.subList(manifestsToRetain - 1, blobMetadata.size())
+                            );
+                        }
+                        deleteStaleMetadataRunning.set(false);
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        logger.error(
+                            new ParameterizedMessage(
+                                "Exception occurred while deleting Remote Cluster Metadata for clusterUUIDs {}",
+                                clusterUUID
+                            )
+                        );
+                        deleteStaleMetadataRunning.set(false);
+                    }
+                }
+            );
+        } finally {
+            deleteStaleMetadataRunning.set(false);
+        }
+    }
+
+    private void deleteClusterMetadata(
+        String clusterName,
+        String clusterUUID,
+        List<BlobMetadata> activeManifestBlobMetadata,
+        List<BlobMetadata> staleManifestBlobMetadata
+    ) {
+        try {
+            Set<String> filesToKeep = new HashSet<>();
+            Set<String> staleManifestPaths = new HashSet<>();
+            Set<String> staleIndexMetadataPaths = new HashSet<>();
+            activeManifestBlobMetadata.forEach(blobMetadata -> {
+                ClusterMetadataManifest clusterMetadataManifest = fetchRemoteClusterMetadataManifest(
+                    clusterName,
+                    clusterUUID,
+                    blobMetadata.name()
+                );
+                clusterMetadataManifest.getIndices()
+                    .forEach(uploadedIndexMetadata -> filesToKeep.add(uploadedIndexMetadata.getUploadedFilename()));
+            });
+            staleManifestBlobMetadata.forEach(blobMetadata -> {
+                ClusterMetadataManifest clusterMetadataManifest = fetchRemoteClusterMetadataManifest(
+                    clusterName,
+                    clusterUUID,
+                    blobMetadata.name()
+                );
+                staleManifestPaths.add(new BlobPath().add(MANIFEST_PATH_TOKEN).buildAsString() + blobMetadata.name());
+                clusterMetadataManifest.getIndices().forEach(uploadedIndexMetadata -> {
+                    if (filesToKeep.contains(uploadedIndexMetadata.getUploadedFilename()) == false) {
+                        staleIndexMetadataPaths.add(
+                            new BlobPath().add(INDEX_PATH_TOKEN).add(uploadedIndexMetadata.getIndexUUID()).buildAsString()
+                                + uploadedIndexMetadata.getUploadedFilename()
+                                + ".dat"
+                        );
+                    }
+                });
+            });
+
+            if (staleManifestPaths.isEmpty()) {
+                logger.info("No stale Remote Cluster Metadata files found");
+                return;
+            }
+
+            deleteStalePaths(clusterName, clusterUUID, new ArrayList<>(staleIndexMetadataPaths));
+            deleteStalePaths(clusterName, clusterUUID, new ArrayList<>(staleManifestPaths));
+        } catch (IllegalStateException e) {
+            logger.error("Error while fetching Remote Cluster Metadata manifests", e);
+        } catch (IOException e) {
+            logger.error("Error while deleting stale Remote Cluster Metadata files", e);
+        } catch (Exception e) {
+            logger.error("Unexpected error while deleting stale Remote Cluster Metadata files", e);
+        }
+    }
+
+    private void deleteStalePaths(String clusterName, String clusterUUID, List<String> stalePaths) throws IOException {
+        logger.debug(String.format(Locale.ROOT, "Deleting stale files from remote - %s", stalePaths));
+        getBlobStoreTransferService().deleteBlobs(getCusterMetadataBasePath(clusterName, clusterUUID), stalePaths);
+    }
+
+    /**
+     * Purges all remote cluster state against provided cluster UUIDs
+     * @param clusterState current state of the cluster
+     * @param committedManifest last committed ClusterMetadataManifest
+     */
+    public void deleteStaleClusterUUIDs(ClusterState clusterState, ClusterMetadataManifest committedManifest) {
+        threadpool.executor(ThreadPool.Names.REMOTE_PURGE).execute(() -> {
+            String clusterName = clusterState.getClusterName().value();
+            logger.info("Deleting stale cluster UUIDs data from remote [{}]", clusterName);
+            Set<String> allClustersUUIDsInRemote;
+            try {
+                allClustersUUIDsInRemote = new HashSet<>(getAllClusterUUIDs(clusterState.getClusterName().value()));
+            } catch (IOException e) {
+                logger.info(String.format(Locale.ROOT, "Error while fetching all cluster UUIDs for [%s]", clusterName));
+                return;
+            }
+            // Retain last 2 cluster uuids data
+            allClustersUUIDsInRemote.remove(committedManifest.getClusterUUID());
+            allClustersUUIDsInRemote.remove(committedManifest.getPreviousClusterUUID());
+            deleteStaleUUIDsClusterMetadata(clusterName, new ArrayList<>(allClustersUUIDsInRemote));
+        });
+    }
+}
diff --git a/server/src/main/java/org/opensearch/gateway/remote/package-info.java b/server/src/main/java/org/opensearch/gateway/remote/package-info.java
new file mode 100644
index 0000000000000..286e739f66289
--- /dev/null
+++ b/server/src/main/java/org/opensearch/gateway/remote/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing class to perform operations on remote cluster state
+ */
+package org.opensearch.gateway.remote;
diff --git a/server/src/main/java/org/opensearch/http/AbstractHttpServerTransport.java b/server/src/main/java/org/opensearch/http/AbstractHttpServerTransport.java
index 8d98370a90538..b8f8abb6c2c23 100644
--- a/server/src/main/java/org/opensearch/http/AbstractHttpServerTransport.java
+++ b/server/src/main/java/org/opensearch/http/AbstractHttpServerTransport.java
@@ -32,30 +32,34 @@
 
 package org.opensearch.http;
 
-import com.carrotsearch.hppc.IntHashSet;
-import com.carrotsearch.hppc.IntSet;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.transport.NetworkExceptionHelper;
 import org.opensearch.common.transport.PortsRange;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanBuilder;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.channels.TraceableHttpChannel;
+import org.opensearch.telemetry.tracing.channels.TraceableRestChannel;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.BindTransportException;
 
@@ -66,6 +70,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -78,6 +83,11 @@
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_PUBLISH_HOST;
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_PUBLISH_PORT;
 
+/**
+ * Base HttpServer class
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractHttpServerTransport extends AbstractLifecycleComponent implements HttpServerTransport {
     private static final Logger logger = LogManager.getLogger(AbstractHttpServerTransport.class);
     private static final ActionListener<Void> NO_OP = ActionListener.wrap(() -> {});
@@ -101,7 +111,8 @@ public abstract class AbstractHttpServerTransport extends AbstractLifecycleCompo
     private final Set<HttpChannel> httpChannels = Collections.newSetFromMap(new ConcurrentHashMap<>());
     private final Set<HttpServerChannel> httpServerChannels = Collections.newSetFromMap(new ConcurrentHashMap<>());
 
-    private final HttpTracer tracer;
+    private final HttpTracer httpTracer;
+    private final Tracer tracer;
 
     protected AbstractHttpServerTransport(
         Settings settings,
@@ -110,7 +121,8 @@ protected AbstractHttpServerTransport(
         ThreadPool threadPool,
         NamedXContentRegistry xContentRegistry,
         Dispatcher dispatcher,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer telemetryTracer
     ) {
         this.settings = settings;
         this.networkService = networkService;
@@ -134,7 +146,8 @@ protected AbstractHttpServerTransport(
         this.port = SETTING_HTTP_PORT.get(settings);
 
         this.maxContentLength = SETTING_HTTP_MAX_CONTENT_LENGTH.get(settings);
-        this.tracer = new HttpTracer(settings, clusterSettings);
+        this.httpTracer = new HttpTracer(settings, clusterSettings);
+        this.tracer = telemetryTracer;
     }
 
     @Override
@@ -259,12 +272,12 @@ static int resolvePublishPort(Settings settings, List<TransportAddress> boundAdd
 
         // if no matching boundAddress found, check if there is a unique port for all bound addresses
         if (publishPort < 0) {
-            final IntSet ports = new IntHashSet();
+            final Set<Integer> ports = new HashSet<>();
             for (TransportAddress boundAddress : boundAddresses) {
                 ports.add(boundAddress.getPort());
             }
             if (ports.size() == 1) {
-                publishPort = ports.iterator().next().value;
+                publishPort = ports.iterator().next();
             }
         }
 
@@ -285,6 +298,7 @@ static int resolvePublishPort(Settings settings, List<TransportAddress> boundAdd
     }
 
     public void onException(HttpChannel channel, Exception e) {
+        channel.handleException(e);
         if (lifecycle.started() == false) {
             // just close and ignore - we are already stopped and just need to make sure we release all resources
             CloseableChannel.closeChannel(channel);
@@ -348,19 +362,31 @@ protected void serverAcceptedChannel(HttpChannel httpChannel) {
      * @param httpChannel that received the http request
      */
     public void incomingRequest(final HttpRequest httpRequest, final HttpChannel httpChannel) {
-        handleIncomingRequest(httpRequest, httpChannel, httpRequest.getInboundException());
+        final Span span = tracer.startSpan(SpanBuilder.from(httpRequest), httpRequest.getHeaders());
+        try (final SpanScope httpRequestSpanScope = tracer.withSpanInScope(span)) {
+            HttpChannel traceableHttpChannel = TraceableHttpChannel.create(httpChannel, span, tracer);
+            handleIncomingRequest(httpRequest, traceableHttpChannel, httpRequest.getInboundException());
+        }
     }
 
     // Visible for testing
     void dispatchRequest(final RestRequest restRequest, final RestChannel channel, final Throwable badRequestCause) {
+        RestChannel traceableRestChannel = channel;
         final ThreadContext threadContext = threadPool.getThreadContext();
         try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
-            if (badRequestCause != null) {
-                dispatcher.dispatchBadRequest(channel, threadContext, badRequestCause);
-            } else {
-                dispatcher.dispatchRequest(restRequest, channel, threadContext);
+            final Span span = tracer.startSpan(SpanBuilder.from(restRequest));
+            try (final SpanScope spanScope = tracer.withSpanInScope(span)) {
+                if (channel != null) {
+                    traceableRestChannel = TraceableRestChannel.create(channel, span, tracer);
+                }
+                if (badRequestCause != null) {
+                    dispatcher.dispatchBadRequest(traceableRestChannel, threadContext, badRequestCause);
+                } else {
+                    dispatcher.dispatchRequest(restRequest, traceableRestChannel, threadContext);
+                }
             }
         }
+
     }
 
     private void handleIncomingRequest(final HttpRequest httpRequest, final HttpChannel httpChannel, final Exception exception) {
@@ -397,7 +423,7 @@ private void handleIncomingRequest(final HttpRequest httpRequest, final HttpChan
             restRequest = innerRestRequest;
         }
 
-        final HttpTracer trace = tracer.maybeTraceRequest(restRequest, exception);
+        final HttpTracer trace = httpTracer.maybeTraceRequest(restRequest, exception);
 
         /*
          * We now want to create a channel used to send the response on. However, creating this channel can fail if there are invalid
diff --git a/server/src/main/java/org/opensearch/http/BindHttpException.java b/server/src/main/java/org/opensearch/http/BindHttpException.java
index cfa537fca9bb7..f7a184e391fa9 100644
--- a/server/src/main/java/org/opensearch/http/BindHttpException.java
+++ b/server/src/main/java/org/opensearch/http/BindHttpException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when trying to bind to an http endpoint
+ *
+ * @opensearch.internal
+ */
 public class BindHttpException extends HttpException {
 
     public BindHttpException(String message) {
diff --git a/server/src/main/java/org/opensearch/http/CorsHandler.java b/server/src/main/java/org/opensearch/http/CorsHandler.java
index 0b2cedf093f33..862c50ae6ac1f 100644
--- a/server/src/main/java/org/opensearch/http/CorsHandler.java
+++ b/server/src/main/java/org/opensearch/http/CorsHandler.java
@@ -47,12 +47,12 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 
 import java.time.ZoneOffset;
@@ -84,6 +84,8 @@
  *
  * It modifies the original netty code to operate on OpenSearch http request/response abstractions.
  * Additionally, it removes CORS features that are not used by OpenSearch.
+ *
+ * @opensearch.internal
  */
 public class CorsHandler {
 
@@ -167,7 +169,7 @@ private void setPreflightHeaders(final HttpResponse response) {
 
     private boolean setOrigin(final HttpRequest request, final HttpResponse response) {
         String origin = getOrigin(request);
-        if (!Strings.isNullOrEmpty(origin)) {
+        if (Strings.isNullOrEmpty(origin) == false) {
             if (config.isAnyOriginSupported()) {
                 if (config.isCredentialsAllowed()) {
                     setAllowOrigin(response, origin);
@@ -259,6 +261,11 @@ private void setMaxAge(final HttpResponse response) {
         response.addHeader(ACCESS_CONTROL_MAX_AGE, Long.toString(config.maxAge));
     }
 
+    /**
+     * The cors handler configuration
+     *
+     * @opensearch.internal
+     */
     public static class Config {
 
         private final boolean enabled;
diff --git a/server/src/main/java/org/opensearch/http/DefaultRestChannel.java b/server/src/main/java/org/opensearch/http/DefaultRestChannel.java
index d94eadf82463a..ef93914b6677c 100644
--- a/server/src/main/java/org/opensearch/http/DefaultRestChannel.java
+++ b/server/src/main/java/org/opensearch/http/DefaultRestChannel.java
@@ -32,10 +32,7 @@
 
 package org.opensearch.http;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
 import org.opensearch.common.lease.Releasable;
@@ -43,11 +40,14 @@
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.AbstractRestChannel;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -58,6 +58,8 @@
 /**
  * The default rest channel for incoming requests. This class implements the basic logic for sending a rest
  * response. It will set necessary headers nad ensure that bytes are released after the response is sent.
+ *
+ * @opensearch.internal
  */
 public class DefaultRestChannel extends AbstractRestChannel implements RestChannel {
 
diff --git a/server/src/main/java/org/opensearch/http/HttpChannel.java b/server/src/main/java/org/opensearch/http/HttpChannel.java
index c309a8c5decad..6dcdaf9034413 100644
--- a/server/src/main/java/org/opensearch/http/HttpChannel.java
+++ b/server/src/main/java/org/opensearch/http/HttpChannel.java
@@ -32,12 +32,22 @@
 
 package org.opensearch.http;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.network.CloseableChannel;
+import org.opensearch.core.action.ActionListener;
 
 import java.net.InetSocketAddress;
 
+/**
+ * Represents an HTTP comms channel
+ *
+ * @opensearch.internal
+ */
 public interface HttpChannel extends CloseableChannel {
+    /**
+     * Notify HTTP channel that exception happens and the response may not be sent (for example, timeout)
+     * @param ex the exception being raised
+     */
+    default void handleException(Exception ex) {}
 
     /**
      * Sends an http response to the channel. The listener will be executed once the send process has been
diff --git a/server/src/main/java/org/opensearch/http/HttpException.java b/server/src/main/java/org/opensearch/http/HttpException.java
index 70fb6a956b8a1..ec78702c77bfe 100644
--- a/server/src/main/java/org/opensearch/http/HttpException.java
+++ b/server/src/main/java/org/opensearch/http/HttpException.java
@@ -33,10 +33,15 @@
 package org.opensearch.http;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown on HTTP requests
+ *
+ * @opensearch.internal
+ */
 public class HttpException extends OpenSearchException {
 
     public HttpException(String message) {
diff --git a/server/src/main/java/org/opensearch/http/HttpHandlingSettings.java b/server/src/main/java/org/opensearch/http/HttpHandlingSettings.java
index 3e9d252bd64d3..37f754d591b22 100644
--- a/server/src/main/java/org/opensearch/http/HttpHandlingSettings.java
+++ b/server/src/main/java/org/opensearch/http/HttpHandlingSettings.java
@@ -46,6 +46,11 @@
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_RESET_COOKIES;
 import static org.opensearch.http.HttpTransportSettings.SETTING_PIPELINING_MAX_EVENTS;
 
+/**
+ * HTTP Settings
+ *
+ * @opensearch.internal
+ */
 public class HttpHandlingSettings {
 
     private final int maxContentLength;
diff --git a/server/src/main/java/org/opensearch/http/HttpInfo.java b/server/src/main/java/org/opensearch/http/HttpInfo.java
index cf49d2621ccfa..10f2d50dacb14 100644
--- a/server/src/main/java/org/opensearch/http/HttpInfo.java
+++ b/server/src/main/java/org/opensearch/http/HttpInfo.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Information about an http connection
+ *
+ * @opensearch.internal
+ */
 public class HttpInfo implements ReportingService.Info {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(HttpInfo.class);
diff --git a/server/src/main/java/org/opensearch/http/HttpPipelinedMessage.java b/server/src/main/java/org/opensearch/http/HttpPipelinedMessage.java
index 4b1a8fc3ddd18..879da973274e5 100644
--- a/server/src/main/java/org/opensearch/http/HttpPipelinedMessage.java
+++ b/server/src/main/java/org/opensearch/http/HttpPipelinedMessage.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.http;
 
+/**
+ * Pipeline messages for http connections
+ *
+ * @opensearch.internal
+ */
 public interface HttpPipelinedMessage extends Comparable<HttpPipelinedMessage> {
 
     /**
diff --git a/server/src/main/java/org/opensearch/http/HttpPipelinedRequest.java b/server/src/main/java/org/opensearch/http/HttpPipelinedRequest.java
index 1ab0b0afd46eb..90ba6be0cc3df 100644
--- a/server/src/main/java/org/opensearch/http/HttpPipelinedRequest.java
+++ b/server/src/main/java/org/opensearch/http/HttpPipelinedRequest.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Pipeline requests for http connections
+ *
+ * @opensearch.internal
+ */
 public class HttpPipelinedRequest implements HttpRequest, HttpPipelinedMessage {
 
     private final int sequence;
diff --git a/server/src/main/java/org/opensearch/http/HttpPipelinedResponse.java b/server/src/main/java/org/opensearch/http/HttpPipelinedResponse.java
index 4729e8f47c5d6..c535d977c0e1a 100644
--- a/server/src/main/java/org/opensearch/http/HttpPipelinedResponse.java
+++ b/server/src/main/java/org/opensearch/http/HttpPipelinedResponse.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.http;
 
+/**
+ * Pipeline responses for http connections
+ *
+ * @opensearch.internal
+ */
 public class HttpPipelinedResponse implements HttpPipelinedMessage, HttpResponse {
 
     private final int sequence;
diff --git a/server/src/main/java/org/opensearch/http/HttpPipeliningAggregator.java b/server/src/main/java/org/opensearch/http/HttpPipeliningAggregator.java
index 46db0aa3a8c4f..df6eb01a0b157 100644
--- a/server/src/main/java/org/opensearch/http/HttpPipeliningAggregator.java
+++ b/server/src/main/java/org/opensearch/http/HttpPipeliningAggregator.java
@@ -38,6 +38,11 @@
 import java.util.List;
 import java.util.PriorityQueue;
 
+/**
+ * Aggregates HTTP requests
+ *
+ * @opensearch.internal
+ */
 public class HttpPipeliningAggregator<Listener> {
 
     private final int maxEventsHeld;
diff --git a/server/src/main/java/org/opensearch/http/HttpReadTimeoutException.java b/server/src/main/java/org/opensearch/http/HttpReadTimeoutException.java
index 86045f7bbbe28..2769ab12730bb 100644
--- a/server/src/main/java/org/opensearch/http/HttpReadTimeoutException.java
+++ b/server/src/main/java/org/opensearch/http/HttpReadTimeoutException.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.http;
 
+/**
+ * Timeout Exception for HTTP read operations
+ *
+ * @opensearch.internal
+ */
 public class HttpReadTimeoutException extends RuntimeException {
 
     public HttpReadTimeoutException(long readTimeoutMillis) {
diff --git a/server/src/main/java/org/opensearch/http/HttpRequest.java b/server/src/main/java/org/opensearch/http/HttpRequest.java
index e0d4e739f1fd4..162ef11a3d865 100644
--- a/server/src/main/java/org/opensearch/http/HttpRequest.java
+++ b/server/src/main/java/org/opensearch/http/HttpRequest.java
@@ -33,9 +33,9 @@
 package org.opensearch.http;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.util.Collections;
 import java.util.List;
@@ -44,9 +44,16 @@
 /**
  * A basic http request abstraction. Http modules needs to implement this interface to integrate with the
  * server package's rest handling.
+ *
+ * @opensearch.internal
  */
 public interface HttpRequest {
 
+    /**
+     * Which HTTP version being used
+     *
+     * @opensearch.internal
+     */
     enum HttpVersion {
         HTTP_1_0,
         HTTP_1_1
diff --git a/server/src/main/java/org/opensearch/http/HttpResponse.java b/server/src/main/java/org/opensearch/http/HttpResponse.java
index bec0a6348cd07..3c8269f4400e7 100644
--- a/server/src/main/java/org/opensearch/http/HttpResponse.java
+++ b/server/src/main/java/org/opensearch/http/HttpResponse.java
@@ -35,6 +35,8 @@
 /**
  * A basic http response abstraction. Http modules must implement this interface as the server package rest
  * handling needs to set http headers for a response.
+ *
+ * @opensearch.internal
  */
 public interface HttpResponse {
 
diff --git a/server/src/main/java/org/opensearch/http/HttpServerChannel.java b/server/src/main/java/org/opensearch/http/HttpServerChannel.java
index 5b9ad2b36f0f4..e57f03c54ce24 100644
--- a/server/src/main/java/org/opensearch/http/HttpServerChannel.java
+++ b/server/src/main/java/org/opensearch/http/HttpServerChannel.java
@@ -36,6 +36,11 @@
 
 import java.net.InetSocketAddress;
 
+/**
+ * Http server channel
+ *
+ * @opensearch.internal
+ */
 public interface HttpServerChannel extends CloseableChannel {
 
     /**
diff --git a/server/src/main/java/org/opensearch/http/HttpServerTransport.java b/server/src/main/java/org/opensearch/http/HttpServerTransport.java
index ad7378073f84f..890136cb67e60 100644
--- a/server/src/main/java/org/opensearch/http/HttpServerTransport.java
+++ b/server/src/main/java/org/opensearch/http/HttpServerTransport.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.component.LifecycleComponent;
-import org.opensearch.common.transport.BoundTransportAddress;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.service.ReportingService;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 
+/**
+ * HTTP Transport server
+ *
+ * @opensearch.internal
+ */
 public interface HttpServerTransport extends LifecycleComponent, ReportingService<HttpInfo> {
 
     String HTTP_SERVER_WORKER_THREAD_NAME_PREFIX = "http_server_worker";
diff --git a/server/src/main/java/org/opensearch/http/HttpStats.java b/server/src/main/java/org/opensearch/http/HttpStats.java
index 11450abcab020..078b84b7bc563 100644
--- a/server/src/main/java/org/opensearch/http/HttpStats.java
+++ b/server/src/main/java/org/opensearch/http/HttpStats.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats for HTTP connections
+ *
+ * @opensearch.internal
+ */
 public class HttpStats implements Writeable, ToXContentFragment {
 
     private final long serverOpen;
diff --git a/server/src/main/java/org/opensearch/http/HttpTracer.java b/server/src/main/java/org/opensearch/http/HttpTracer.java
index a57694dc9adf4..7a763b9ffb790 100644
--- a/server/src/main/java/org/opensearch/http/HttpTracer.java
+++ b/server/src/main/java/org/opensearch/http/HttpTracer.java
@@ -36,9 +36,9 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.tasks.Task;
@@ -48,6 +48,8 @@
 
 /**
  * Http request trace logger. See {@link #maybeTraceRequest(RestRequest, Exception)} for details.
+ *
+ * @opensearch.internal
  */
 class HttpTracer {
 
diff --git a/server/src/main/java/org/opensearch/http/HttpTransportSettings.java b/server/src/main/java/org/opensearch/http/HttpTransportSettings.java
index 8ab881907fc2e..f16f06f414e28 100644
--- a/server/src/main/java/org/opensearch/http/HttpTransportSettings.java
+++ b/server/src/main/java/org/opensearch/http/HttpTransportSettings.java
@@ -37,9 +37,9 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.transport.PortsRange;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.Collections;
 import java.util.List;
@@ -50,6 +50,11 @@
 import static org.opensearch.common.settings.Setting.intSetting;
 import static org.opensearch.common.settings.Setting.listSetting;
 
+/**
+ * Transport settings for http connections
+ *
+ * @opensearch.internal
+ */
 public final class HttpTransportSettings {
 
     public static final Setting<Boolean> SETTING_CORS_ENABLED = Setting.boolSetting("http.cors.enabled", false, Property.NodeScope);
diff --git a/server/src/main/java/org/opensearch/http/HttpUtils.java b/server/src/main/java/org/opensearch/http/HttpUtils.java
index 825e3ad756e78..39eee29a57ac3 100644
--- a/server/src/main/java/org/opensearch/http/HttpUtils.java
+++ b/server/src/main/java/org/opensearch/http/HttpUtils.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.http;
 
+/**
+ * Utility class for HTTP connections
+ *
+ * @opensearch.internal
+ */
 public class HttpUtils {
 
     static final String CLOSE = "close";
diff --git a/server/src/main/java/org/opensearch/http/package-info.java b/server/src/main/java/org/opensearch/http/package-info.java
new file mode 100644
index 0000000000000..814c82450e5ad
--- /dev/null
+++ b/server/src/main/java/org/opensearch/http/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core http module implementing http transport request and responses */
+package org.opensearch.http;
diff --git a/server/src/main/java/org/opensearch/identity/IdentityService.java b/server/src/main/java/org/opensearch/identity/IdentityService.java
new file mode 100644
index 0000000000000..c85ad451549de
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/IdentityService.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.identity;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.identity.noop.NoopIdentityPlugin;
+import org.opensearch.identity.tokens.TokenManager;
+import org.opensearch.plugins.IdentityPlugin;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Identity and access control for OpenSearch
+ *
+ * @opensearch.experimental
+ * */
+public class IdentityService {
+    private static final Logger log = LogManager.getLogger(IdentityService.class);
+
+    private final Settings settings;
+    private final IdentityPlugin identityPlugin;
+
+    public IdentityService(final Settings settings, final List<IdentityPlugin> identityPlugins) {
+        this.settings = settings;
+
+        if (identityPlugins.size() == 0) {
+            log.debug("Identity plugins size is 0");
+            identityPlugin = new NoopIdentityPlugin();
+        } else if (identityPlugins.size() == 1) {
+            log.debug("Identity plugins size is 1");
+            identityPlugin = identityPlugins.get(0);
+        } else {
+            throw new OpenSearchException(
+                "Multiple identity plugins are not supported, found: "
+                    + identityPlugins.stream().map(Object::getClass).map(Class::getName).collect(Collectors.joining(","))
+            );
+        }
+    }
+
+    /**
+     * Gets the current subject
+     */
+    public Subject getSubject() {
+        return identityPlugin.getSubject();
+    }
+
+    /**
+     * Gets the token manager
+     */
+    public TokenManager getTokenManager() {
+        return identityPlugin.getTokenManager();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/NamedPrincipal.java b/server/src/main/java/org/opensearch/identity/NamedPrincipal.java
new file mode 100644
index 0000000000000..f30d307bdf592
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/NamedPrincipal.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.identity;
+
+import java.security.Principal;
+import java.util.Objects;
+
+/**
+ * Create a principal from a string
+ *
+ * @opensearch.experimental
+ */
+public class NamedPrincipal implements Principal {
+
+    /**
+     * Represents a principal which has not been authenticated
+     */
+    public static final NamedPrincipal UNAUTHENTICATED = new NamedPrincipal("Unauthenticated");
+
+    private final String name;
+
+    /**
+     * Creates a principal for an identity specified as a string
+     * @param name A persistent string that represent an identity
+     */
+    public NamedPrincipal(final String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        final Principal that = (Principal) obj;
+        return Objects.equals(name, that.getName());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name);
+    }
+
+    @Override
+    public String toString() {
+        return "NamedPrincipal(" + "name=" + name + ")";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/Subject.java b/server/src/main/java/org/opensearch/identity/Subject.java
new file mode 100644
index 0000000000000..cbfdadb5cf6a7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/Subject.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.identity;
+
+import org.opensearch.identity.tokens.AuthToken;
+
+import java.security.Principal;
+
+/**
+ * An individual, process, or device that causes information to flow among objects or change to the system state.
+ *
+ * @opensearch.experimental
+ */
+public interface Subject {
+
+    /**
+     * Get the application-wide uniquely identifying principal
+     * */
+    Principal getPrincipal();
+
+    /**
+     * Authenticate via an auth token
+     * throws UnsupportedAuthenticationMethod
+     * throws InvalidAuthenticationToken
+     * throws SubjectNotFound
+     * throws SubjectDisabled
+     */
+    void authenticate(final AuthToken token);
+}
diff --git a/server/src/main/java/org/opensearch/identity/noop/NoopIdentityPlugin.java b/server/src/main/java/org/opensearch/identity/noop/NoopIdentityPlugin.java
new file mode 100644
index 0000000000000..c2367383df595
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/noop/NoopIdentityPlugin.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.noop;
+
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.TokenManager;
+import org.opensearch.plugins.IdentityPlugin;
+
+/**
+ * Implementation of identity plugin that does not enforce authentication or authorization
+ *
+ * This class and related classes in this package will not return nulls or fail access checks
+ *
+ * @opensearch.internal
+ */
+public class NoopIdentityPlugin implements IdentityPlugin {
+
+    /**
+     * Get the current subject
+     * @return Must never return null
+     */
+    @Override
+    public Subject getSubject() {
+        return new NoopSubject();
+    }
+
+    /**
+     * Get a new NoopTokenManager
+     * @return Must never return null
+     */
+    @Override
+    public TokenManager getTokenManager() {
+        return new NoopTokenManager();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/noop/NoopSubject.java b/server/src/main/java/org/opensearch/identity/noop/NoopSubject.java
new file mode 100644
index 0000000000000..424a10204aa19
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/noop/NoopSubject.java
@@ -0,0 +1,57 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.noop;
+
+import org.opensearch.identity.NamedPrincipal;
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.AuthToken;
+
+import java.security.Principal;
+import java.util.Objects;
+
+/**
+ * Implementation of subject that is always authenticated
+ *
+ * This class and related classes in this package will not return nulls or fail permissions checks
+ *
+ * @opensearch.internal
+ */
+public class NoopSubject implements Subject {
+
+    @Override
+    public Principal getPrincipal() {
+        return NamedPrincipal.UNAUTHENTICATED;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        Subject that = (Subject) obj;
+        return Objects.equals(getPrincipal(), that.getPrincipal());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getPrincipal());
+    }
+
+    @Override
+    public String toString() {
+        return "NoopSubject(principal=" + getPrincipal() + ")";
+    }
+
+    /**
+     * Logs the user in
+     */
+    @Override
+    public void authenticate(AuthToken AuthToken) {
+        // Do nothing as noop subject is always logged in
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/noop/NoopTokenManager.java b/server/src/main/java/org/opensearch/identity/noop/NoopTokenManager.java
new file mode 100644
index 0000000000000..a55f28e02a8aa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/noop/NoopTokenManager.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.noop;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.identity.tokens.AuthToken;
+import org.opensearch.identity.tokens.TokenManager;
+
+/**
+ * This class represents a Noop Token Manager
+ */
+public class NoopTokenManager implements TokenManager {
+
+    private static final Logger log = LogManager.getLogger(IdentityService.class);
+
+    /**
+     * Issue a new Noop Token
+     * @return a new Noop Token
+     */
+    @Override
+    public AuthToken issueToken(String audience) {
+        return new AuthToken() {
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/noop/package-info.java b/server/src/main/java/org/opensearch/identity/noop/package-info.java
new file mode 100644
index 0000000000000..fcdd70db7f020
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/noop/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for the noop authentication in OpenSearch */
+package org.opensearch.identity.noop;
diff --git a/server/src/main/java/org/opensearch/identity/package-info.java b/server/src/main/java/org/opensearch/identity/package-info.java
new file mode 100644
index 0000000000000..4693206af62a5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/package-info.java
@@ -0,0 +1,7 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/** Core identity and access controls for OpenSearch */
+package org.opensearch.identity;
diff --git a/server/src/main/java/org/opensearch/identity/tokens/AuthToken.java b/server/src/main/java/org/opensearch/identity/tokens/AuthToken.java
new file mode 100644
index 0000000000000..6e113f6eaa96a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/AuthToken.java
@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.tokens;
+
+/**
+ * Interface for all token formats to support to authenticate user such as UserName/Password tokens, Access tokens, and more.
+ *
+ * @opensearch.experimental
+ */
+public interface AuthToken {
+
+}
diff --git a/server/src/main/java/org/opensearch/identity/tokens/BasicAuthToken.java b/server/src/main/java/org/opensearch/identity/tokens/BasicAuthToken.java
new file mode 100644
index 0000000000000..9cd6cb6b6208a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/BasicAuthToken.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.tokens;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+/**
+ * Basic (Base64 encoded) Authentication Token in a http request header
+ */
+public final class BasicAuthToken implements AuthToken {
+
+    public final static String TOKEN_IDENTIFIER = "Basic";
+
+    private String user;
+    private String password;
+
+    public BasicAuthToken(final String headerValue) {
+        final String base64Encoded = headerValue.substring(TOKEN_IDENTIFIER.length()).trim();
+        final byte[] rawDecoded = Base64.getDecoder().decode(base64Encoded);
+        final String usernamepassword = new String(rawDecoded, StandardCharsets.UTF_8);
+
+        final String[] tokenParts = usernamepassword.split(":", 2);
+        if (tokenParts.length != 2) {
+            throw new IllegalStateException("Illegally formed basic authorization header " + tokenParts[0]);
+        }
+        user = tokenParts[0];
+        password = tokenParts[1];
+    }
+
+    public String getUser() {
+        return user;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    @Override
+    public String toString() {
+        return "Basic auth token with user=" + user + ", password=" + password;
+    }
+
+    public void revoke() {
+        this.password = "";
+        this.user = "";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/tokens/BearerAuthToken.java b/server/src/main/java/org/opensearch/identity/tokens/BearerAuthToken.java
new file mode 100644
index 0000000000000..eac164af1c5d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/BearerAuthToken.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.tokens;
+
+/**
+ * Bearer (JWT) Authentication Token in a http request header
+ */
+public class BearerAuthToken implements AuthToken {
+
+    public final String DELIMITER = "\\.";
+    public final static String TOKEN_IDENTIFIER = "Bearer";
+
+    private String header;
+    private String payload;
+    private String signature;
+
+    private String completeToken;
+
+    public BearerAuthToken(final String token) {
+
+        String[] tokenComponents = token.split(DELIMITER);
+        if (tokenComponents.length != 3) {
+            throw new IllegalArgumentException("Illegally formed bearer authorization token " + token);
+        }
+        completeToken = token;
+        header = tokenComponents[0];
+        payload = tokenComponents[1];
+        signature = tokenComponents[2];
+    }
+
+    public String getHeader() {
+        return header;
+    }
+
+    public String getPayload() {
+        return payload;
+    }
+
+    public String getSignature() {
+        return signature;
+    }
+
+    public String getCompleteToken() {
+        return completeToken;
+    }
+
+    public String getTokenIdentifier() {
+        return TOKEN_IDENTIFIER;
+    }
+
+    @Override
+    public String toString() {
+        return "Bearer auth token with header=" + header + ", payload=" + payload + ", signature=" + signature;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/tokens/RestTokenExtractor.java b/server/src/main/java/org/opensearch/identity/tokens/RestTokenExtractor.java
new file mode 100644
index 0000000000000..193966001f44c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/RestTokenExtractor.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.identity.tokens;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.core.common.Strings;
+import org.opensearch.rest.RestRequest;
+
+import java.util.Collections;
+import java.util.Optional;
+
+/**
+ * Extracts tokens from RestRequests used for authentication
+ */
+public class RestTokenExtractor {
+
+    private static final Logger logger = LogManager.getLogger(RestTokenExtractor.class);
+
+    public final static String AUTH_HEADER_NAME = "Authorization";
+
+    /**
+     * Given a rest request it will extract authentication token
+     *
+     * If no token was found, returns null.
+     */
+    public static AuthToken extractToken(final RestRequest request) {
+
+        // Extract authentication information from headers
+        final Optional<String> authHeaderValue = request.getHeaders()
+            .getOrDefault(AUTH_HEADER_NAME, Collections.emptyList())
+            .stream()
+            .findFirst();
+
+        if (authHeaderValue.isPresent()) {
+            final String authHeaderValueStr = authHeaderValue.get();
+
+            if (authHeaderValueStr.startsWith(BasicAuthToken.TOKEN_IDENTIFIER)) {
+                return new BasicAuthToken(authHeaderValueStr);
+            } else {
+                if (logger.isDebugEnabled()) {
+                    String tokenTypeTruncated = Strings.substring(authHeaderValueStr, 0, 5);
+                    logger.debug("An authentication header was detected but the token type was not supported " + tokenTypeTruncated);
+                }
+            }
+        }
+
+        logger.trace("No auth token could be extracted");
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/identity/tokens/TokenManager.java b/server/src/main/java/org/opensearch/identity/tokens/TokenManager.java
new file mode 100644
index 0000000000000..029ce430e7532
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/TokenManager.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.identity.tokens;
+
+/**
+ * This interface defines the expected methods of a token manager
+ */
+public interface TokenManager {
+
+    /**
+     * Create a new auth token
+     * @param audience: The audience for the token
+     * @return A new auth token
+     */
+    public AuthToken issueToken(String audience);
+}
diff --git a/server/src/main/java/org/opensearch/identity/tokens/package-info.java b/server/src/main/java/org/opensearch/identity/tokens/package-info.java
new file mode 100644
index 0000000000000..b63ea40c61659
--- /dev/null
+++ b/server/src/main/java/org/opensearch/identity/tokens/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for the authentication tokens in OpenSearch */
+package org.opensearch.identity.tokens;
diff --git a/server/src/main/java/org/opensearch/index/AbstractIndexComponent.java b/server/src/main/java/org/opensearch/index/AbstractIndexComponent.java
index e63216494a5b2..7b3705f921954 100644
--- a/server/src/main/java/org/opensearch/index/AbstractIndexComponent.java
+++ b/server/src/main/java/org/opensearch/index/AbstractIndexComponent.java
@@ -35,7 +35,13 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.logging.Loggers;
+import org.opensearch.core.index.Index;
 
+/**
+ * A base class for new index components
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractIndexComponent implements IndexComponent {
 
     protected final Logger logger;
diff --git a/server/src/main/java/org/opensearch/index/CompositeIndexEventListener.java b/server/src/main/java/org/opensearch/index/CompositeIndexEventListener.java
index 79c97d1126e93..001a34c46c72b 100644
--- a/server/src/main/java/org/opensearch/index/CompositeIndexEventListener.java
+++ b/server/src/main/java/org/opensearch/index/CompositeIndexEventListener.java
@@ -38,10 +38,11 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
 
 import java.util.ArrayList;
@@ -51,6 +52,8 @@
 
 /**
  * A composite {@link IndexEventListener} that forwards all callbacks to an immutable list of IndexEventListener
+ *
+ * @opensearch.internal
  */
 final class CompositeIndexEventListener implements IndexEventListener {
 
diff --git a/server/src/main/java/org/opensearch/index/Index.java b/server/src/main/java/org/opensearch/index/Index.java
deleted file mode 100644
index 5284bc7d23c71..0000000000000
--- a/server/src/main/java/org/opensearch/index/Index.java
+++ /dev/null
@@ -1,154 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index;
-
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-
-import java.io.IOException;
-import java.util.Objects;
-
-/**
- * A value class representing the basic required properties of an OpenSearch index.
- */
-public class Index implements Writeable, ToXContentObject {
-
-    public static final Index[] EMPTY_ARRAY = new Index[0];
-    private static final String INDEX_UUID_KEY = "index_uuid";
-    private static final String INDEX_NAME_KEY = "index_name";
-    private static final ObjectParser<Builder, Void> INDEX_PARSER = new ObjectParser<>("index", Builder::new);
-    static {
-        INDEX_PARSER.declareString(Builder::name, new ParseField(INDEX_NAME_KEY));
-        INDEX_PARSER.declareString(Builder::uuid, new ParseField(INDEX_UUID_KEY));
-    }
-
-    private final String name;
-    private final String uuid;
-
-    public Index(String name, String uuid) {
-        this.name = Objects.requireNonNull(name);
-        this.uuid = Objects.requireNonNull(uuid);
-    }
-
-    /**
-     * Read from a stream.
-     */
-    public Index(StreamInput in) throws IOException {
-        this.name = in.readString();
-        this.uuid = in.readString();
-    }
-
-    public String getName() {
-        return this.name;
-    }
-
-    public String getUUID() {
-        return uuid;
-    }
-
-    @Override
-    public String toString() {
-        /*
-         * If we have a uuid we put it in the toString so it'll show up in logs which is useful as more and more things use the uuid rather
-         * than the name as the lookup key for the index.
-         */
-        if (ClusterState.UNKNOWN_UUID.equals(uuid)) {
-            return "[" + name + "]";
-        }
-        return "[" + name + "/" + uuid + "]";
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass()) {
-            return false;
-        }
-        Index index1 = (Index) o;
-        return uuid.equals(index1.uuid) && name.equals(index1.name); // allow for _na_ uuid
-    }
-
-    @Override
-    public int hashCode() {
-        int result = name.hashCode();
-        result = 31 * result + uuid.hashCode();
-        return result;
-    }
-
-    @Override
-    public void writeTo(final StreamOutput out) throws IOException {
-        out.writeString(name);
-        out.writeString(uuid);
-    }
-
-    @Override
-    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
-        builder.startObject();
-        builder.field(INDEX_NAME_KEY, name);
-        builder.field(INDEX_UUID_KEY, uuid);
-        return builder.endObject();
-    }
-
-    public static Index fromXContent(final XContentParser parser) throws IOException {
-        return INDEX_PARSER.parse(parser, null).build();
-    }
-
-    /**
-     * Builder for Index objects.  Used by ObjectParser instances only.
-     */
-    private static final class Builder {
-        private String name;
-        private String uuid;
-
-        public void name(final String name) {
-            this.name = name;
-        }
-
-        public void uuid(final String uuid) {
-            this.uuid = uuid;
-        }
-
-        public Index build() {
-            return new Index(name, uuid);
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/index/IndexComponent.java b/server/src/main/java/org/opensearch/index/IndexComponent.java
index 16387e7cfb80c..fe57abe2c907e 100644
--- a/server/src/main/java/org/opensearch/index/IndexComponent.java
+++ b/server/src/main/java/org/opensearch/index/IndexComponent.java
@@ -32,6 +32,13 @@
 
 package org.opensearch.index;
 
+import org.opensearch.core.index.Index;
+
+/**
+ * Actions that can be executed on an Index Component
+ *
+ * @opensearch.internal
+ */
 public interface IndexComponent {
 
     Index index();
diff --git a/server/src/main/java/org/opensearch/index/IndexModule.java b/server/src/main/java/org/opensearch/index/IndexModule.java
index 61f6c9689308f..8692876412ea9 100644
--- a/server/src/main/java/org/opensearch/index/IndexModule.java
+++ b/server/src/main/java/org/opensearch/index/IndexModule.java
@@ -40,21 +40,26 @@
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.MMapDirectory;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.analysis.AnalysisRegistry;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -70,12 +75,15 @@
 import org.opensearch.index.shard.SearchOperationListener;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.index.store.FsDirectoryFactory;
+import org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.indices.IndicesQueryCache;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.plugins.IndexStorePlugin;
+import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
 import org.opensearch.threadpool.ThreadPool;
@@ -85,6 +93,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -94,6 +103,7 @@
 import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 /**
  * IndexModule represents the central extension point for index level custom implementations like:
@@ -109,7 +119,10 @@
  *      <li>Settings update listener - Custom settings update listener can be registered via
  *      {@link #addSettingsUpdateConsumer(Setting, Consumer)}</li>
  * </ul>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class IndexModule {
 
     public static final Setting<Boolean> NODE_STORE_ALLOW_MMAP = Setting.boolSetting("node.store.allow_mmap", true, Property.NodeScope);
@@ -145,6 +158,109 @@ public final class IndexModule {
         Property.NodeScope
     );
 
+    /** Which lucene file extensions to load with the mmap directory when using hybridfs store. This settings is ignored if {@link #INDEX_STORE_HYBRID_NIO_EXTENSIONS} is set.
+     *  This is an expert setting.
+     *  @see <a href="https://lucene.apache.org/core/9_5_0/core/org/apache/lucene/codecs/lucene95/package-summary.html#file-names">Lucene File Extensions</a>.
+     *
+     * @deprecated This setting will be removed in OpenSearch 3.x. Use {@link #INDEX_STORE_HYBRID_NIO_EXTENSIONS} instead.
+     */
+    @Deprecated
+    public static final Setting<List<String>> INDEX_STORE_HYBRID_MMAP_EXTENSIONS = Setting.listSetting(
+        "index.store.hybrid.mmap.extensions",
+        List.of("nvd", "dvd", "tim", "tip", "dim", "kdd", "kdi", "cfs", "doc"),
+        Function.identity(),
+        new Setting.Validator<List<String>>() {
+
+            @Override
+            public void validate(final List<String> value) {}
+
+            @Override
+            public void validate(final List<String> value, final Map<Setting<?>, Object> settings) {
+                if (value.equals(INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getDefault(Settings.EMPTY)) == false) {
+                    final List<String> nioExtensions = (List<String>) settings.get(INDEX_STORE_HYBRID_NIO_EXTENSIONS);
+                    final List<String> defaultNioExtensions = INDEX_STORE_HYBRID_NIO_EXTENSIONS.getDefault(Settings.EMPTY);
+                    if (nioExtensions.equals(defaultNioExtensions) == false) {
+                        throw new IllegalArgumentException(
+                            "Settings "
+                                + INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey()
+                                + " & "
+                                + INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey()
+                                + " cannot both be set. Use "
+                                + INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey()
+                                + " only."
+                        );
+                    }
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                return List.<Setting<?>>of(INDEX_STORE_HYBRID_NIO_EXTENSIONS).iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.NodeScope,
+        Property.Deprecated
+    );
+
+    /** Which lucene file extensions to load with nio. All others will default to mmap. Takes precedence over {@link #INDEX_STORE_HYBRID_MMAP_EXTENSIONS}.
+     *  This is an expert setting.
+     *  @see <a href="https://lucene.apache.org/core/9_5_0/core/org/apache/lucene/codecs/lucene95/package-summary.html#file-names">Lucene File Extensions</a>.
+     */
+    public static final Setting<List<String>> INDEX_STORE_HYBRID_NIO_EXTENSIONS = Setting.listSetting(
+        "index.store.hybrid.nio.extensions",
+        List.of(
+            "segments_N",
+            "write.lock",
+            "si",
+            "cfe",
+            "fnm",
+            "fdx",
+            "fdt",
+            "pos",
+            "pay",
+            "nvm",
+            "dvm",
+            "tvx",
+            "tvd",
+            "liv",
+            "dii",
+            "vem"
+        ),
+        Function.identity(),
+        new Setting.Validator<List<String>>() {
+
+            @Override
+            public void validate(final List<String> value) {}
+
+            @Override
+            public void validate(final List<String> value, final Map<Setting<?>, Object> settings) {
+                if (value.equals(INDEX_STORE_HYBRID_NIO_EXTENSIONS.getDefault(Settings.EMPTY)) == false) {
+                    final List<String> mmapExtensions = (List<String>) settings.get(INDEX_STORE_HYBRID_MMAP_EXTENSIONS);
+                    final List<String> defaultMmapExtensions = INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getDefault(Settings.EMPTY);
+                    if (mmapExtensions.equals(defaultMmapExtensions) == false) {
+                        throw new IllegalArgumentException(
+                            "Settings "
+                                + INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey()
+                                + " & "
+                                + INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey()
+                                + " cannot both be set. Use "
+                                + INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey()
+                                + " only."
+                        );
+                    }
+                }
+            }
+
+            @Override
+            public Iterator<Setting<?>> settings() {
+                return List.<Setting<?>>of(INDEX_STORE_HYBRID_MMAP_EXTENSIONS).iterator();
+            }
+        },
+        Property.IndexScope,
+        Property.NodeScope
+    );
+
     public static final String SIMILARITY_SETTINGS_PREFIX = "index.similarity";
 
     // whether to use the query cache
@@ -184,9 +300,9 @@ public final class IndexModule {
      * Construct the index module for the index with the specified index settings. The index module contains extension points for plugins
      * via {@link org.opensearch.plugins.PluginsService#onIndexModule(IndexModule)}.
      *
-     * @param indexSettings       the index settings
-     * @param analysisRegistry    the analysis registry
-     * @param engineFactory       the engine factory
+     * @param indexSettings      the index settings
+     * @param analysisRegistry   the analysis registry
+     * @param engineFactory      the engine factory
      * @param directoryFactories the available store types
      */
     public IndexModule(
@@ -376,21 +492,18 @@ IndexEventListener freeze() { // pkg private for testing
         }
     }
 
-    public static boolean isBuiltinType(String storeType) {
-        for (Type type : Type.values()) {
-            if (type.match(storeType)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
+    /**
+     * Type of file system
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         HYBRIDFS("hybridfs"),
         NIOFS("niofs"),
         MMAPFS("mmapfs"),
         SIMPLEFS("simplefs"),
-        FS("fs");
+        FS("fs"),
+        REMOTE_SNAPSHOT("remote_snapshot");
 
         private final String settingsKey;
         private final boolean deprecated;
@@ -407,7 +520,7 @@ public enum Type {
         private static final Map<String, Type> TYPES;
 
         static {
-            final Map<String, Type> types = new HashMap<>(4);
+            final Map<String, Type> types = new HashMap<>(values().length);
             for (final Type type : values()) {
                 types.put(type.settingsKey, type);
             }
@@ -422,6 +535,10 @@ public boolean isDeprecated() {
             return deprecated;
         }
 
+        static boolean containsSettingsKey(String key) {
+            return TYPES.containsKey(key);
+        }
+
         public static Type fromSettingsKey(final String key) {
             final Type type = TYPES.get(key);
             if (type == null) {
@@ -440,6 +557,21 @@ public boolean match(String setting) {
             return getSettingsKey().equals(setting);
         }
 
+        /**
+         * Convenience method to check whether the given {@link IndexSettings}
+         * object contains an {@link #INDEX_STORE_TYPE_SETTING} set to the value of this type.
+         */
+        public boolean match(IndexSettings settings) {
+            return match(settings.getSettings());
+        }
+
+        /**
+         * Convenience method to check whether the given {@link Settings}
+         * object contains an {@link #INDEX_STORE_TYPE_SETTING} set to the value of this type.
+         */
+        public boolean match(Settings settings) {
+            return match(INDEX_STORE_TYPE_SETTING.get(settings));
+        }
     }
 
     public static Type defaultStoreType(final boolean allowMmap) {
@@ -466,7 +598,11 @@ public IndexService newIndexService(
         IndicesFieldDataCache indicesFieldDataCache,
         NamedWriteableRegistry namedWriteableRegistry,
         BooleanSupplier idFieldDataEnabled,
-        ValuesSourceRegistry valuesSourceRegistry
+        ValuesSourceRegistry valuesSourceRegistry,
+        IndexStorePlugin.DirectoryFactory remoteDirectoryFactory,
+        BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier,
+        Supplier<TimeValue> clusterDefaultRefreshIntervalSupplier,
+        Supplier<TimeValue> clusterRemoteTranslogBufferIntervalSupplier
     ) throws IOException {
         final IndexEventListener eventListener = freeze();
         Function<IndexService, CheckedFunction<DirectoryReader, DirectoryReader, IOException>> readerWrapperFactory = indexReaderWrapper
@@ -509,6 +645,7 @@ public IndexService newIndexService(
                 client,
                 queryCache,
                 directoryFactory,
+                remoteDirectoryFactory,
                 eventListener,
                 readerWrapperFactory,
                 mapperRegistry,
@@ -520,7 +657,10 @@ public IndexService newIndexService(
                 allowExpensiveQueries,
                 expressionResolver,
                 valuesSourceRegistry,
-                recoveryStateFactory
+                recoveryStateFactory,
+                translogFactorySupplier,
+                clusterDefaultRefreshIntervalSupplier,
+                clusterRemoteTranslogBufferIntervalSupplier
             );
             success = true;
             return indexService;
@@ -541,7 +681,7 @@ private static IndexStorePlugin.DirectoryFactory getDirectoryFactory(
         if (storeType.isEmpty() || Type.FS.getSettingsKey().equals(storeType)) {
             type = defaultStoreType(allowMmap);
         } else {
-            if (isBuiltinType(storeType)) {
+            if (Type.containsSettingsKey(storeType)) {
                 type = Type.fromSettingsKey(storeType);
             } else {
                 type = null;
@@ -551,7 +691,7 @@ private static IndexStorePlugin.DirectoryFactory getDirectoryFactory(
             throw new IllegalArgumentException("store type [" + storeType + "] is not allowed because mmap is disabled");
         }
         final IndexStorePlugin.DirectoryFactory factory;
-        if (storeType.isEmpty() || isBuiltinType(storeType)) {
+        if (storeType.isEmpty()) {
             factory = DEFAULT_DIRECTORY_FACTORY;
         } else {
             factory = indexStoreFactories.get(storeType);
@@ -595,7 +735,9 @@ public MapperService newIndexMapperService(
             xContentRegistry,
             new SimilarityService(indexSettings, scriptService, similarities),
             mapperRegistry,
-            () -> { throw new UnsupportedOperationException("no index query shard context available"); },
+            () -> {
+                throw new UnsupportedOperationException("no index query shard context available");
+            },
             () -> false,
             scriptService
         );
@@ -620,4 +762,31 @@ private void ensureNotFrozen() {
         }
     }
 
+    public static Map<String, IndexStorePlugin.DirectoryFactory> createBuiltInDirectoryFactories(
+        Supplier<RepositoriesService> repositoriesService,
+        ThreadPool threadPool,
+        FileCache remoteStoreFileCache
+    ) {
+        final Map<String, IndexStorePlugin.DirectoryFactory> factories = new HashMap<>();
+        for (Type type : Type.values()) {
+            switch (type) {
+                case HYBRIDFS:
+                case NIOFS:
+                case FS:
+                case MMAPFS:
+                case SIMPLEFS:
+                    factories.put(type.getSettingsKey(), DEFAULT_DIRECTORY_FACTORY);
+                    break;
+                case REMOTE_SNAPSHOT:
+                    factories.put(
+                        type.getSettingsKey(),
+                        new RemoteSnapshotDirectoryFactory(repositoriesService, threadPool, remoteStoreFileCache)
+                    );
+                    break;
+                default:
+                    throw new IllegalStateException("No directory factory mapping for built-in type " + type);
+            }
+        }
+        return factories;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/IndexNotFoundException.java b/server/src/main/java/org/opensearch/index/IndexNotFoundException.java
index f4c8f38844efd..f1459fcffa395 100644
--- a/server/src/main/java/org/opensearch/index/IndexNotFoundException.java
+++ b/server/src/main/java/org/opensearch/index/IndexNotFoundException.java
@@ -32,10 +32,16 @@
 package org.opensearch.index;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an index is not found
+ *
+ * @opensearch.internal
+ */
 public final class IndexNotFoundException extends ResourceNotFoundException {
     /**
      * Construct with a custom message.
diff --git a/server/src/main/java/org/opensearch/index/IndexService.java b/server/src/main/java/org/opensearch/index/IndexService.java
index 1b301e85365ba..df8e8070b8e03 100644
--- a/server/src/main/java/org/opensearch/index/IndexService.java
+++ b/server/src/main/java/org/opensearch/index/IndexService.java
@@ -40,7 +40,6 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.Accountable;
-import org.opensearch.Assertions;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
@@ -49,7 +48,6 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
@@ -57,8 +55,12 @@
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.AbstractAsyncTask;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
 import org.opensearch.env.ShardLockObtainFailedException;
@@ -76,24 +78,26 @@
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.SearchIndexNameMatcher;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
 import org.opensearch.index.shard.IndexingOperationListener;
 import org.opensearch.index.shard.SearchOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.similarity.SimilarityService;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
@@ -112,6 +116,7 @@
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BiFunction;
 import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -122,6 +127,11 @@
 import static java.util.Collections.unmodifiableMap;
 import static org.opensearch.common.collect.MapBuilder.newMapBuilder;
 
+/**
+ * The main OpenSearch index service
+ *
+ * @opensearch.internal
+ */
 public class IndexService extends AbstractIndexComponent implements IndicesClusterStateService.AllocatedIndex<IndexShard> {
 
     private final IndexEventListener eventListener;
@@ -130,6 +140,7 @@ public class IndexService extends AbstractIndexComponent implements IndicesClust
     private final NodeEnvironment nodeEnv;
     private final ShardStoreDeleter shardStoreDeleter;
     private final IndexStorePlugin.DirectoryFactory directoryFactory;
+    private final IndexStorePlugin.DirectoryFactory remoteDirectoryFactory;
     private final IndexStorePlugin.RecoveryStateFactory recoveryStateFactory;
     private final CheckedFunction<DirectoryReader, DirectoryReader, IOException> readerWrapper;
     private final IndexCache indexCache;
@@ -165,6 +176,9 @@ public class IndexService extends AbstractIndexComponent implements IndicesClust
     private final IndexNameExpressionResolver expressionResolver;
     private final Supplier<Sort> indexSortSupplier;
     private final ValuesSourceRegistry valuesSourceRegistry;
+    private final BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier;
+    private final Supplier<TimeValue> clusterDefaultRefreshIntervalSupplier;
+    private final Supplier<TimeValue> clusterRemoteTranslogBufferIntervalSupplier;
 
     public IndexService(
         IndexSettings indexSettings,
@@ -184,6 +198,7 @@ public IndexService(
         Client client,
         QueryCache queryCache,
         IndexStorePlugin.DirectoryFactory directoryFactory,
+        IndexStorePlugin.DirectoryFactory remoteDirectoryFactory,
         IndexEventListener eventListener,
         Function<IndexService, CheckedFunction<DirectoryReader, DirectoryReader, IOException>> wrapperFactory,
         MapperRegistry mapperRegistry,
@@ -195,7 +210,10 @@ public IndexService(
         BooleanSupplier allowExpensiveQueries,
         IndexNameExpressionResolver expressionResolver,
         ValuesSourceRegistry valuesSourceRegistry,
-        IndexStorePlugin.RecoveryStateFactory recoveryStateFactory
+        IndexStorePlugin.RecoveryStateFactory recoveryStateFactory,
+        BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier,
+        Supplier<TimeValue> clusterDefaultRefreshIntervalSupplier,
+        Supplier<TimeValue> clusterRemoteTranslogBufferIntervalSupplier
     ) {
         super(indexSettings);
         this.allowExpensiveQueries = allowExpensiveQueries;
@@ -223,8 +241,10 @@ public IndexService(
             if (indexSettings.getIndexSortConfig().hasIndexSort()) {
                 // we delay the actual creation of the sort order for this index because the mapping has not been merged yet.
                 // The sort order is validated right after the merge of the mapping later in the process.
+                boolean shouldWidenIndexSortType = this.indexSettings.shouldWidenIndexSortType();
                 this.indexSortSupplier = () -> indexSettings.getIndexSortConfig()
                     .buildIndexSort(
+                        shouldWidenIndexSortType,
                         mapperService::fieldType,
                         (fieldType, searchLookup) -> indexFieldData.getForField(fieldType, indexFieldData.index().getName(), searchLookup)
                     );
@@ -254,6 +274,7 @@ public IndexService(
         this.eventListener = eventListener;
         this.nodeEnv = nodeEnv;
         this.directoryFactory = directoryFactory;
+        this.remoteDirectoryFactory = remoteDirectoryFactory;
         this.recoveryStateFactory = recoveryStateFactory;
         this.engineFactory = Objects.requireNonNull(engineFactory);
         this.engineConfigFactory = Objects.requireNonNull(engineConfigFactory);
@@ -261,11 +282,14 @@ public IndexService(
         this.readerWrapper = wrapperFactory.apply(this);
         this.searchOperationListeners = Collections.unmodifiableList(searchOperationListeners);
         this.indexingOperationListeners = Collections.unmodifiableList(indexingOperationListeners);
+        this.clusterDefaultRefreshIntervalSupplier = clusterDefaultRefreshIntervalSupplier;
         // kick off async ops for the first shard in this index
         this.refreshTask = new AsyncRefreshTask(this);
         this.trimTranslogTask = new AsyncTrimTranslogTask(this);
         this.globalCheckpointTask = new AsyncGlobalCheckpointTask(this);
         this.retentionLeaseSyncTask = new AsyncRetentionLeaseSyncTask(this);
+        this.translogFactorySupplier = translogFactorySupplier;
+        this.clusterRemoteTranslogBufferIntervalSupplier = clusterRemoteTranslogBufferIntervalSupplier;
         updateFsyncTaskIfNecessary();
     }
 
@@ -274,6 +298,11 @@ static boolean needsMapperService(IndexSettings indexSettings, IndexCreationCont
             && indexCreationContext == IndexCreationContext.CREATE_INDEX); // metadata verification needs a mapper service
     }
 
+    /**
+     * Context for index creation
+     *
+     * @opensearch.internal
+     */
     public enum IndexCreationContext {
         CREATE_INDEX,
         METADATA_VERIFICATION
@@ -418,7 +447,9 @@ private long getAvgShardSizeInBytes() throws IOException {
     public synchronized IndexShard createShard(
         final ShardRouting routing,
         final Consumer<ShardId> globalCheckpointSyncer,
-        final RetentionLeaseSyncer retentionLeaseSyncer
+        final RetentionLeaseSyncer retentionLeaseSyncer,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
+        final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
     ) throws IOException {
         Objects.requireNonNull(retentionLeaseSyncer);
         /*
@@ -438,66 +469,30 @@ public synchronized IndexShard createShard(
         try {
             lock = nodeEnv.shardLock(shardId, "starting shard", TimeUnit.SECONDS.toMillis(5));
             eventListener.beforeIndexShardCreated(shardId, indexSettings);
-            ShardPath path;
-            try {
-                path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings.customDataPath());
-            } catch (IllegalStateException ex) {
-                logger.warn("{} failed to load shard path, trying to remove leftover", shardId);
-                try {
-                    ShardPath.deleteLeftoverShardDirectory(logger, nodeEnv, lock, this.indexSettings);
-                    path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings.customDataPath());
-                } catch (Exception inner) {
-                    ex.addSuppressed(inner);
-                    throw ex;
-                }
-            }
-
-            if (path == null) {
-                // TODO: we should, instead, hold a "bytes reserved" of how large we anticipate this shard will be, e.g. for a shard
-                // that's being relocated/replicated we know how large it will become once it's done copying:
-                // Count up how many shards are currently on each data path:
-                Map<Path, Integer> dataPathToShardCount = new HashMap<>();
-                for (IndexShard shard : this) {
-                    Path dataPath = shard.shardPath().getRootStatePath();
-                    Integer curCount = dataPathToShardCount.get(dataPath);
-                    if (curCount == null) {
-                        curCount = 0;
-                    }
-                    dataPathToShardCount.put(dataPath, curCount + 1);
-                }
-                path = ShardPath.selectNewPathForShard(
-                    nodeEnv,
-                    shardId,
-                    this.indexSettings,
-                    routing.getExpectedShardSize() == ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE
-                        ? getAvgShardSizeInBytes()
-                        : routing.getExpectedShardSize(),
-                    dataPathToShardCount
-                );
-                logger.debug("{} creating using a new path [{}]", shardId, path);
-            } else {
-                logger.debug("{} creating using an existing path [{}]", shardId, path);
-            }
-
-            if (shards.containsKey(shardId.id())) {
-                throw new IllegalStateException(shardId + " already exists");
-            }
-
+            ShardPath path = getShardPath(routing, shardId, lock);
             logger.debug("creating shard_id {}", shardId);
-            // if we are on a shared FS we only own the shard (ie. we can safely delete it) if we are the primary.
+            // if we are on a shared FS we only own the shard (i.e. we can safely delete it) if we are the primary.
             final Engine.Warmer engineWarmer = (reader) -> {
                 IndexShard shard = getShardOrNull(shardId.getId());
                 if (shard != null) {
                     warmer.warm(reader, shard, IndexService.this.indexSettings);
                 }
             };
+
+            Store remoteStore = null;
+            if (this.indexSettings.isRemoteStoreEnabled()) {
+                Directory remoteDirectory = remoteDirectoryFactory.newDirectory(this.indexSettings, path);
+                remoteStore = new Store(shardId, this.indexSettings, remoteDirectory, lock, Store.OnClose.EMPTY, path);
+            }
+
             Directory directory = directoryFactory.newDirectory(this.indexSettings, path);
             store = new Store(
                 shardId,
                 this.indexSettings,
                 directory,
                 lock,
-                new StoreCloseListener(shardId, () -> eventListener.onStoreClosed(shardId))
+                new StoreCloseListener(shardId, () -> eventListener.onStoreClosed(shardId)),
+                path
             );
             eventListener.onStoreCreated(shardId);
             indexShard = new IndexShard(
@@ -520,7 +515,14 @@ public synchronized IndexShard createShard(
                 indexingOperationListeners,
                 () -> globalCheckpointSyncer.accept(shardId),
                 retentionLeaseSyncer,
-                circuitBreakerService
+                circuitBreakerService,
+                translogFactorySupplier,
+                this.indexSettings.isSegRepEnabled() ? checkpointPublisher : null,
+                remoteStore,
+                remoteStoreStatsTrackerFactory,
+                clusterRemoteTranslogBufferIntervalSupplier,
+                nodeEnv.nodeId(),
+                (RemoteSegmentStoreDirectoryFactory) remoteDirectoryFactory
             );
             eventListener.indexShardStateChanged(indexShard, null, indexShard.state(), "shard created");
             eventListener.afterIndexShardCreated(indexShard);
@@ -539,6 +541,63 @@ public synchronized IndexShard createShard(
         }
     }
 
+    /*
+      Fetches the shard path based on the index type -
+      For a remote snapshot index, the cache path is used to initialize the shards.
+      For a local index, a local shard path is loaded or a new path is calculated.
+     */
+    private ShardPath getShardPath(ShardRouting routing, ShardId shardId, ShardLock lock) throws IOException {
+        ShardPath path;
+        if (this.indexSettings.isRemoteSnapshot()) {
+            path = ShardPath.loadFileCachePath(nodeEnv, shardId);
+        } else {
+            try {
+                path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings.customDataPath());
+            } catch (IllegalStateException ex) {
+                logger.warn("{} failed to load shard path, trying to remove leftover", shardId);
+                try {
+                    ShardPath.deleteLeftoverShardDirectory(logger, nodeEnv, lock, this.indexSettings);
+                    path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings.customDataPath());
+                } catch (Exception inner) {
+                    ex.addSuppressed(inner);
+                    throw ex;
+                }
+            }
+
+            if (path == null) {
+                // TODO: we should, instead, hold a "bytes reserved" of how large we anticipate this shard will be, e.g. for a shard
+                // that's being relocated/replicated we know how large it will become once it's done copying:
+                // Count up how many shards are currently on each data path:
+                Map<Path, Integer> dataPathToShardCount = new HashMap<>();
+                for (IndexShard shard : this) {
+                    Path dataPath = shard.shardPath().getRootStatePath();
+                    Integer curCount = dataPathToShardCount.get(dataPath);
+                    if (curCount == null) {
+                        curCount = 0;
+                    }
+                    dataPathToShardCount.put(dataPath, curCount + 1);
+                }
+                path = ShardPath.selectNewPathForShard(
+                    nodeEnv,
+                    shardId,
+                    this.indexSettings,
+                    routing.getExpectedShardSize() == ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE
+                        ? getAvgShardSizeInBytes()
+                        : routing.getExpectedShardSize(),
+                    dataPathToShardCount
+                );
+                logger.debug("{} creating using a new path [{}]", shardId, path);
+            } else {
+                logger.debug("{} creating using an existing path [{}]", shardId, path);
+            }
+        }
+
+        if (shards.containsKey(shardId.id())) {
+            throw new IllegalStateException(shardId + " already exists");
+        }
+        return path;
+    }
+
     @Override
     public synchronized void removeShard(int shardId, String reason) {
         final ShardId sId = new ShardId(index(), shardId);
@@ -557,6 +616,10 @@ public synchronized void removeShard(int shardId, String reason) {
     private void closeShard(String reason, ShardId sId, IndexShard indexShard, Store store, IndexEventListener listener) {
         final int shardId = sId.id();
         final Settings indexSettings = this.getIndexSettings().getSettings();
+        Store remoteStore = null;
+        if (indexShard != null) {
+            remoteStore = indexShard.remoteStore();
+        }
         if (store != null) {
             store.beforeClose();
         }
@@ -570,7 +633,7 @@ private void closeShard(String reason, ShardId sId, IndexShard indexShard, Store
                     try {
                         // only flush if we are closed (closed index or shutdown) and if we are not deleted
                         final boolean flushEngine = deleted.get() == false && closed.get();
-                        indexShard.close(reason, flushEngine);
+                        indexShard.close(reason, flushEngine, deleted.get());
                     } catch (Exception e) {
                         logger.debug(() -> new ParameterizedMessage("[{}] failed to close index shard", shardId), e);
                         // ignore
@@ -586,6 +649,11 @@ private void closeShard(String reason, ShardId sId, IndexShard indexShard, Store
                 } else {
                     logger.trace("[{}] store not initialized prior to closing shard, nothing to close", shardId);
                 }
+
+                if (remoteStore != null && indexShard.isPrimaryMode() && deleted.get()) {
+                    remoteStore.close();
+                }
+
             } catch (Exception e) {
                 logger.warn(
                     () -> new ParameterizedMessage("[{}] failed to close store on shard removal (reason: [{}])", shardId, reason),
@@ -736,6 +804,11 @@ public void accept(ShardLock lock) {
         }
     }
 
+    /**
+     * Cache listener for bitsets
+     *
+     * @opensearch.internal
+     */
     private static final class BitsetCacheListener implements BitsetFilterCache.Listener {
         final IndexService indexService;
 
@@ -835,36 +908,47 @@ public synchronized void updateMetadata(final IndexMetadata currentIndexMetadata
                     );
                 }
             }
-            if (refreshTask.getInterval().equals(indexSettings.getRefreshInterval()) == false) {
-                // once we change the refresh interval we schedule yet another refresh
-                // to ensure we are in a clean and predictable state.
-                // it doesn't matter if we move from or to <code>-1</code> in both cases we want
-                // docs to become visible immediately. This also flushes all pending indexing / search requests
-                // that are waiting for a refresh.
-                threadPool.executor(ThreadPool.Names.REFRESH).execute(new AbstractRunnable() {
-                    @Override
-                    public void onFailure(Exception e) {
-                        logger.warn("forced refresh failed after interval change", e);
-                    }
-
-                    @Override
-                    protected void doRun() throws Exception {
-                        maybeRefreshEngine(true);
-                    }
-
-                    @Override
-                    public boolean isForceExecution() {
-                        return true;
-                    }
-                });
-                rescheduleRefreshTasks();
-            }
+            onRefreshIntervalChange();
             updateFsyncTaskIfNecessary();
         }
 
         metadataListeners.forEach(c -> c.accept(newIndexMetadata));
     }
 
+    /**
+     * Called whenever the refresh interval changes. This can happen in 2 cases -
+     * 1. {@code cluster.default.index.refresh_interval} cluster setting changes. The change would only happen for
+     * indexes relying on cluster default.
+     * 2. {@code index.refresh_interval} index setting changes.
+     */
+    public void onRefreshIntervalChange() {
+        if (refreshTask.getInterval().equals(getRefreshInterval())) {
+            return;
+        }
+        // once we change the refresh interval we schedule yet another refresh
+        // to ensure we are in a clean and predictable state.
+        // it doesn't matter if we move from or to <code>-1</code> in both cases we want
+        // docs to become visible immediately. This also flushes all pending indexing / search requests
+        // that are waiting for a refresh.
+        threadPool.executor(ThreadPool.Names.REFRESH).execute(new AbstractRunnable() {
+            @Override
+            public void onFailure(Exception e) {
+                logger.warn("forced refresh failed after interval change", e);
+            }
+
+            @Override
+            protected void doRun() throws Exception {
+                maybeRefreshEngine(true);
+            }
+
+            @Override
+            public boolean isForceExecution() {
+                return true;
+            }
+        });
+        rescheduleRefreshTasks();
+    }
+
     private void updateFsyncTaskIfNecessary() {
         if (indexSettings.getTranslogDurability() == Translog.Durability.REQUEST) {
             try {
@@ -889,6 +973,11 @@ private void rescheduleRefreshTasks() {
         }
     }
 
+    /**
+     * Shard Store Deleter Interface
+     *
+     * @opensearch.internal
+     */
     public interface ShardStoreDeleter {
         void deleteShardStore(String reason, ShardLock lock, IndexSettings indexSettings) throws IOException;
 
@@ -924,7 +1013,7 @@ private void maybeFSyncTranslogs() {
     }
 
     private void maybeRefreshEngine(boolean force) {
-        if (indexSettings.getRefreshInterval().millis() > 0 || force) {
+        if (getRefreshInterval().millis() > 0 || force) {
             for (IndexShard shard : this.shards.values()) {
                 try {
                     shard.scheduledRefresh();
@@ -995,6 +1084,22 @@ private void sync(final Consumer<IndexShard> sync, final String source) {
         }
     }
 
+    /**
+     * Gets the refresh interval seen by the index service. Index setting overrides takes the highest precedence.
+     * @return the refresh interval.
+     */
+    private TimeValue getRefreshInterval() {
+        if (getIndexSettings().isExplicitRefresh()) {
+            return getIndexSettings().getRefreshInterval();
+        }
+        return clusterDefaultRefreshIntervalSupplier.get();
+    }
+
+    /**
+     * Base asynchronous task
+     *
+     * @opensearch.internal
+     */
     abstract static class BaseAsyncTask extends AbstractAsyncTask {
 
         protected final IndexService indexService;
@@ -1015,6 +1120,8 @@ protected boolean mustReschedule() {
 
     /**
      * FSyncs the translog for all shards of this index in a defined interval.
+     *
+     * @opensearch.internal
      */
     static final class AsyncTranslogFSync extends BaseAsyncTask {
 
@@ -1048,7 +1155,7 @@ public String toString() {
     final class AsyncRefreshTask extends BaseAsyncTask {
 
         AsyncRefreshTask(IndexService indexService) {
-            super(indexService, indexService.getIndexSettings().getRefreshInterval());
+            super(indexService, indexService.getRefreshInterval());
         }
 
         @Override
@@ -1170,6 +1277,11 @@ AsyncRefreshTask getRefreshTask() { // for tests
         return refreshTask;
     }
 
+    // Visible for test
+    public TimeValue getRefreshTaskInterval() {
+        return refreshTask.getInterval();
+    }
+
     AsyncTranslogFSync getFsyncTask() { // for tests
         return fsyncTask;
     }
diff --git a/server/src/main/java/org/opensearch/index/IndexSettings.java b/server/src/main/java/org/opensearch/index/IndexSettings.java
index 45d9a57442049..52bdcfa4a0819 100644
--- a/server/src/main/java/org/opensearch/index/IndexSettings.java
+++ b/server/src/main/java/org/opensearch/index/IndexSettings.java
@@ -32,35 +32,47 @@
 package org.opensearch.index;
 
 import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.util.Strings;
 import org.apache.lucene.index.MergePolicy;
+import org.apache.lucene.sandbox.index.MergeOnFlushMergePolicy;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.node.Node;
+import org.opensearch.search.pipeline.SearchPipelineService;
 
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.function.UnaryOperator;
 
+import static org.opensearch.Version.V_2_7_0;
+import static org.opensearch.common.util.FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY;
 import static org.opensearch.index.mapper.MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING;
 import static org.opensearch.index.mapper.MapperService.INDEX_MAPPING_FIELD_NAME_LENGTH_LIMIT_SETTING;
 import static org.opensearch.index.mapper.MapperService.INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING;
 import static org.opensearch.index.mapper.MapperService.INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING;
 import static org.opensearch.index.mapper.MapperService.INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING;
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectory.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION;
 
 /**
  * This class encapsulates all index level settings and handles settings updates.
@@ -68,8 +80,47 @@
  * the latest updated settings instance. Classes that need to listen to settings updates can register
  * a settings consumer at index creation via {@link IndexModule#addSettingsUpdateConsumer(Setting, Consumer)} that will
  * be called for each settings update.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class IndexSettings {
+    private static final String DEFAULT_POLICY = "default";
+    private static final String MERGE_ON_FLUSH_MERGE_POLICY = "merge-on-flush";
+
+    /**
+     * Enum representing supported merge policies
+     */
+    public enum IndexMergePolicy {
+        TIERED("tiered"),
+        LOG_BYTE_SIZE("log_byte_size"),
+        DEFAULT_POLICY(IndexSettings.DEFAULT_POLICY);
+
+        private final String value;
+
+        IndexMergePolicy(String value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            return value;
+        }
+
+        public static IndexMergePolicy fromString(String text) {
+            for (IndexMergePolicy policy : IndexMergePolicy.values()) {
+                if (policy.value.equals(text)) {
+                    return policy;
+                }
+            }
+            throw new IllegalArgumentException(
+                "The setting has unsupported policy specified: "
+                    + text
+                    + ". Please use one of: "
+                    + String.join(", ", Arrays.stream(IndexMergePolicy.values()).map(IndexMergePolicy::getValue).toArray(String[]::new))
+            );
+        }
+    }
+
     public static final Setting<List<String>> DEFAULT_FIELD_SETTING = Setting.listSetting(
         "index.query.default_field",
         Collections.singletonList("*"),
@@ -286,10 +337,11 @@ public final class IndexSettings {
         Property.Deprecated
     );
     public static final TimeValue DEFAULT_REFRESH_INTERVAL = new TimeValue(1, TimeUnit.SECONDS);
+    public static final TimeValue MINIMUM_REFRESH_INTERVAL = new TimeValue(-1, TimeUnit.MILLISECONDS);
     public static final Setting<TimeValue> INDEX_REFRESH_INTERVAL_SETTING = Setting.timeSetting(
         "index.refresh_interval",
         DEFAULT_REFRESH_INTERVAL,
-        new TimeValue(-1, TimeUnit.MILLISECONDS),
+        MINIMUM_REFRESH_INTERVAL,
         Property.Dynamic,
         Property.IndexScope
     );
@@ -448,6 +500,17 @@ public final class IndexSettings {
         Property.IndexScope
     );
 
+    /**
+     * The maximum number of slices allowed in a search request with PIT
+     */
+    public static final Setting<Integer> MAX_SLICES_PER_PIT = Setting.intSetting(
+        "index.max_slices_per_pit",
+        1024,
+        1,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
     /**
      * The maximum length of regex string allowed in a regexp query.
      */
@@ -486,6 +549,18 @@ public final class IndexSettings {
         Property.Dynamic
     );
 
+    /**
+     * This setting controls if unreferenced files will be cleaned up in case segment merge fails due to disk full.
+     *
+     * Defaults to true which means unreferenced files will be cleaned up in case segment merge fails.
+     */
+    public static final Setting<Boolean> INDEX_UNREFERENCED_FILE_CLEANUP = Setting.boolSetting(
+        "index.unreferenced_file_cleanup.enabled",
+        true,
+        Property.IndexScope,
+        Property.Dynamic
+    );
+
     /**
      * Determines a balance between file-based and operations-based peer recoveries. The number of operations that will be used in an
      * operations-based peer recovery is limited to this proportion of the total number of documents in the shard (including deleted
@@ -503,12 +578,110 @@ public final class IndexSettings {
         Setting.Property.IndexScope
     );
 
+    /**
+     * Expert: sets the amount of time to wait for merges (during {@link org.apache.lucene.index.IndexWriter#commit}
+     * or {@link org.apache.lucene.index.IndexWriter#getReader(boolean, boolean)}) returned by MergePolicy.findFullFlushMerges(...).
+     * If this time is reached, we proceed with the commit based on segments merged up to that point. The merges are not
+     * aborted, and will still run to completion independent of the commit or getReader call, like natural segment merges.
+     */
+    public static final Setting<TimeValue> INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME = Setting.timeSetting(
+        "index.merge_on_flush.max_full_flush_merge_wait_time",
+        new TimeValue(10, TimeUnit.SECONDS),
+        new TimeValue(1, TimeUnit.MILLISECONDS),
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
+    public static final Setting<Boolean> INDEX_MERGE_ON_FLUSH_ENABLED = Setting.boolSetting(
+        "index.merge_on_flush.enabled",
+        true, /* https://issues.apache.org/jira/browse/LUCENE-10078 */
+        Property.IndexScope,
+        Property.Dynamic
+    );
+
+    public static final Setting<String> INDEX_MERGE_ON_FLUSH_POLICY = Setting.simpleString(
+        "index.merge_on_flush.policy",
+        DEFAULT_POLICY,
+        Property.IndexScope,
+        Property.Dynamic
+    );
+
+    public static final Setting<String> INDEX_MERGE_POLICY = Setting.simpleString(
+        "index.merge.policy",
+        DEFAULT_POLICY,
+        IndexMergePolicy::fromString,
+        Property.IndexScope
+    );
+
+    public static final Setting<String> TIME_SERIES_INDEX_MERGE_POLICY = Setting.simpleString(
+        "indices.time_series_index.default_index_merge_policy",
+        DEFAULT_POLICY,
+        IndexMergePolicy::fromString,
+        Property.NodeScope
+    );
+
+    public static final Setting<String> SEARCHABLE_SNAPSHOT_REPOSITORY = Setting.simpleString(
+        "index.searchable_snapshot.repository",
+        Property.IndexScope,
+        Property.InternalIndex
+    );
+
+    public static final Setting<String> SEARCHABLE_SNAPSHOT_ID_UUID = Setting.simpleString(
+        "index.searchable_snapshot.snapshot_id.uuid",
+        Property.IndexScope,
+        Property.InternalIndex
+    );
+
+    public static final Setting<String> SEARCHABLE_SNAPSHOT_ID_NAME = Setting.simpleString(
+        "index.searchable_snapshot.snapshot_id.name",
+        Property.IndexScope,
+        Property.InternalIndex
+    );
+
+    public static final Setting<String> SEARCHABLE_SNAPSHOT_INDEX_ID = Setting.simpleString(
+        "index.searchable_snapshot.index.id",
+        Property.IndexScope,
+        Property.InternalIndex
+    );
+
+    public static final Setting<String> DEFAULT_SEARCH_PIPELINE = new Setting<>(
+        "index.search.default_pipeline",
+        SearchPipelineService.NOOP_PIPELINE_ID,
+        Function.identity(),
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
+    public static final Setting<Boolean> INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING = Setting.boolSetting(
+        "index.search.concurrent_segment_search.enabled",
+        false,
+        Property.IndexScope,
+        Property.Dynamic
+    );
+
+    public static final TimeValue DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL = new TimeValue(650, TimeUnit.MILLISECONDS);
+    public static final TimeValue MINIMUM_REMOTE_TRANSLOG_BUFFER_INTERVAL = TimeValue.ZERO;
+    public static final Setting<TimeValue> INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING = Setting.timeSetting(
+        "index.remote_store.translog.buffer_interval",
+        DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+        MINIMUM_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
     private final Index index;
     private final Version version;
     private final Logger logger;
     private final String nodeName;
     private final Settings nodeSettings;
     private final int numberOfShards;
+    private final ReplicationType replicationType;
+    private final boolean isRemoteStoreEnabled;
+    private volatile TimeValue remoteTranslogUploadBufferInterval;
+    private final String remoteStoreTranslogRepository;
+    private final String remoteStoreRepository;
+    private final boolean isRemoteSnapshot;
+    private Version extendedCompatibilitySnapshotVersion;
     // volatile fields are updated via #updateIndexMetadata(IndexMetadata) under lock
     private volatile Settings settings;
     private volatile IndexMetadata indexMetadata;
@@ -526,7 +699,8 @@ public final class IndexSettings {
     private volatile ByteSizeValue generationThresholdSize;
     private volatile ByteSizeValue flushAfterMergeThresholdSize;
     private final MergeSchedulerConfig mergeSchedulerConfig;
-    private final MergePolicyConfig mergePolicyConfig;
+    private final TieredMergePolicyProvider tieredMergePolicyProvider;
+    private final LogByteSizeMergePolicyProvider logByteSizeMergePolicyProvider;
     private final IndexSortConfig indexSortConfig;
     private final IndexScopedSettings scopedSettings;
     private long gcDeletesInMillis = DEFAULT_GC_DELETES.millis();
@@ -535,6 +709,9 @@ public final class IndexSettings {
 
     private volatile long retentionLeaseMillis;
 
+    private volatile String defaultSearchPipeline;
+    private final boolean widenIndexSortType;
+
     /**
      * The maximum age of a retention lease before it is considered expired.
      *
@@ -564,6 +741,7 @@ private void setRetentionLeaseMillis(final TimeValue retentionLease) {
     private volatile String defaultPipeline;
     private volatile String requiredPipeline;
     private volatile boolean searchThrottled;
+    private volatile boolean shouldCleanupUnreferencedFiles;
     private volatile long mappingNestedFieldsLimit;
     private volatile long mappingNestedDocsLimit;
     private volatile long mappingTotalFieldsLimit;
@@ -578,12 +756,28 @@ private void setRetentionLeaseMillis(final TimeValue retentionLease) {
      * The maximum number of slices allowed in a scroll request.
      */
     private volatile int maxSlicesPerScroll;
-
+    /**
+     * The maximum number of slices allowed in a PIT request.
+     */
+    private volatile int maxSlicesPerPit;
     /**
      * The maximum length of regex string allowed in a regexp query.
      */
     private volatile int maxRegexLength;
 
+    /**
+     * The max amount of time to wait for merges
+     */
+    private volatile TimeValue maxFullFlushMergeWaitTime;
+    /**
+     * Is merge of flush enabled or not
+     */
+    private volatile boolean mergeOnFlushEnabled;
+    /**
+     * Specialized merge-on-flush policy if provided
+     */
+    private volatile UnaryOperator<MergePolicy> mergeOnFlushPolicy;
+
     /**
      * Returns the default search fields for this index.
      */
@@ -651,8 +845,20 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         nodeName = Node.NODE_NAME_SETTING.get(settings);
         this.indexMetadata = indexMetadata;
         numberOfShards = settings.getAsInt(IndexMetadata.SETTING_NUMBER_OF_SHARDS, null);
-
+        replicationType = IndexMetadata.INDEX_REPLICATION_TYPE_SETTING.get(settings);
+        isRemoteStoreEnabled = settings.getAsBoolean(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false);
+        remoteStoreTranslogRepository = settings.get(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY);
+        remoteTranslogUploadBufferInterval = INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(settings);
+        remoteStoreRepository = settings.get(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY);
+        isRemoteSnapshot = IndexModule.Type.REMOTE_SNAPSHOT.match(this.settings);
+
+        if (isRemoteSnapshot && FeatureFlags.isEnabled(SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY)) {
+            extendedCompatibilitySnapshotVersion = SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION;
+        } else {
+            extendedCompatibilitySnapshotVersion = Version.CURRENT.minimumIndexCompatibilityVersion();
+        }
         this.searchThrottled = INDEX_SEARCH_THROTTLED.get(settings);
+        this.shouldCleanupUnreferencedFiles = INDEX_UNREFERENCED_FILE_CLEANUP.get(settings);
         this.queryStringLenient = QUERY_STRING_LENIENT_SETTING.get(settings);
         this.queryStringAnalyzeWildcard = QUERY_STRING_ANALYZE_WILDCARD.get(nodeSettings);
         this.queryStringAllowLeadingWildcard = QUERY_STRING_ALLOW_LEADING_WILDCARD.get(nodeSettings);
@@ -682,10 +888,12 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         maxShingleDiff = scopedSettings.get(MAX_SHINGLE_DIFF_SETTING);
         maxRefreshListeners = scopedSettings.get(MAX_REFRESH_LISTENERS_PER_SHARD);
         maxSlicesPerScroll = scopedSettings.get(MAX_SLICES_PER_SCROLL);
+        maxSlicesPerPit = scopedSettings.get(MAX_SLICES_PER_PIT);
         maxAnalyzedOffset = scopedSettings.get(MAX_ANALYZED_OFFSET_SETTING);
         maxTermsCount = scopedSettings.get(MAX_TERMS_COUNT_SETTING);
         maxRegexLength = scopedSettings.get(MAX_REGEX_LENGTH_SETTING);
-        this.mergePolicyConfig = new MergePolicyConfig(logger, this);
+        this.tieredMergePolicyProvider = new TieredMergePolicyProvider(logger, this);
+        this.logByteSizeMergePolicyProvider = new LogByteSizeMergePolicyProvider(logger, this);
         this.indexSortConfig = new IndexSortConfig(this);
         searchIdleAfter = scopedSettings.get(INDEX_SEARCH_IDLE_AFTER);
         defaultPipeline = scopedSettings.get(DEFAULT_PIPELINE);
@@ -696,33 +904,70 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         mappingTotalFieldsLimit = scopedSettings.get(INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING);
         mappingDepthLimit = scopedSettings.get(INDEX_MAPPING_DEPTH_LIMIT_SETTING);
         mappingFieldNameLengthLimit = scopedSettings.get(INDEX_MAPPING_FIELD_NAME_LENGTH_LIMIT_SETTING);
-
-        scopedSettings.addSettingsUpdateConsumer(MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING, mergePolicyConfig::setNoCFSRatio);
+        maxFullFlushMergeWaitTime = scopedSettings.get(INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME);
+        mergeOnFlushEnabled = scopedSettings.get(INDEX_MERGE_ON_FLUSH_ENABLED);
+        setMergeOnFlushPolicy(scopedSettings.get(INDEX_MERGE_ON_FLUSH_POLICY));
+        defaultSearchPipeline = scopedSettings.get(DEFAULT_SEARCH_PIPELINE);
+        /* There was unintentional breaking change got introduced with [OpenSearch-6424](https://github.com/opensearch-project/OpenSearch/pull/6424) (version 2.7).
+         * For indices created prior version (prior to 2.7) which has IndexSort type, they used to type cast the SortField.Type
+         * to higher bytes size like integer to long. This behavior was changed from OpenSearch 2.7 version not to
+         * up cast the SortField to gain some sort query optimizations.
+         * Now this sortField (IndexSort) is stored in SegmentInfo and we need to maintain backward compatibility for them.
+         */
+        widenIndexSortType = IndexMetadata.SETTING_INDEX_VERSION_CREATED.get(settings).before(V_2_7_0);
+        scopedSettings.addSettingsUpdateConsumer(
+            TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING,
+            tieredMergePolicyProvider::setNoCFSRatio
+        );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING,
-            mergePolicyConfig::setDeletesPctAllowed
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING,
+            tieredMergePolicyProvider::setDeletesPctAllowed
         );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING,
-            mergePolicyConfig::setExpungeDeletesAllowed
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING,
+            tieredMergePolicyProvider::setExpungeDeletesAllowed
         );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING,
-            mergePolicyConfig::setFloorSegmentSetting
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING,
+            tieredMergePolicyProvider::setFloorSegmentSetting
         );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING,
-            mergePolicyConfig::setMaxMergesAtOnce
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING,
+            tieredMergePolicyProvider::setMaxMergesAtOnce
         );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING,
-            mergePolicyConfig::setMaxMergedSegment
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING,
+            tieredMergePolicyProvider::setMaxMergedSegment
         );
         scopedSettings.addSettingsUpdateConsumer(
-            MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING,
-            mergePolicyConfig::setSegmentsPerTier
+            TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING,
+            tieredMergePolicyProvider::setSegmentsPerTier
         );
 
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MERGE_FACTOR_SETTING,
+            logByteSizeMergePolicyProvider::setLBSMergeFactor
+        );
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MIN_MERGE_SETTING,
+            logByteSizeMergePolicyProvider::setLBSMinMergedMB
+        );
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_SETTING,
+            logByteSizeMergePolicyProvider::setLBSMaxMergeSegment
+        );
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_FOR_FORCED_MERGE_SETTING,
+            logByteSizeMergePolicyProvider::setLBSMaxMergeMBForForcedMerge
+        );
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGED_DOCS_SETTING,
+            logByteSizeMergePolicyProvider::setLBSMaxMergeDocs
+        );
+        scopedSettings.addSettingsUpdateConsumer(
+            LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING,
+            logByteSizeMergePolicyProvider::setLBSNoCFSRatio
+        );
         scopedSettings.addSettingsUpdateConsumer(
             MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING,
             MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING,
@@ -752,6 +997,7 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         scopedSettings.addSettingsUpdateConsumer(MAX_ANALYZED_OFFSET_SETTING, this::setHighlightMaxAnalyzedOffset);
         scopedSettings.addSettingsUpdateConsumer(MAX_TERMS_COUNT_SETTING, this::setMaxTermsCount);
         scopedSettings.addSettingsUpdateConsumer(MAX_SLICES_PER_SCROLL, this::setMaxSlicesPerScroll);
+        scopedSettings.addSettingsUpdateConsumer(MAX_SLICES_PER_PIT, this::setMaxSlicesPerPit);
         scopedSettings.addSettingsUpdateConsumer(DEFAULT_FIELD_SETTING, this::setDefaultFields);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SEARCH_IDLE_AFTER, this::setSearchIdleAfter);
         scopedSettings.addSettingsUpdateConsumer(MAX_REGEX_LENGTH_SETTING, this::setMaxRegexLength);
@@ -759,15 +1005,27 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         scopedSettings.addSettingsUpdateConsumer(FINAL_PIPELINE, this::setRequiredPipeline);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING, this::setSoftDeleteRetentionOperations);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SEARCH_THROTTLED, this::setSearchThrottled);
+        scopedSettings.addSettingsUpdateConsumer(INDEX_UNREFERENCED_FILE_CLEANUP, this::setShouldCleanupUnreferencedFiles);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SOFT_DELETES_RETENTION_LEASE_PERIOD_SETTING, this::setRetentionLeaseMillis);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING, this::setMappingNestedFieldsLimit);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING, this::setMappingNestedDocsLimit);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING, this::setMappingTotalFieldsLimit);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_DEPTH_LIMIT_SETTING, this::setMappingDepthLimit);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_FIELD_NAME_LENGTH_LIMIT_SETTING, this::setMappingFieldNameLengthLimit);
+        scopedSettings.addSettingsUpdateConsumer(INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME, this::setMaxFullFlushMergeWaitTime);
+        scopedSettings.addSettingsUpdateConsumer(INDEX_MERGE_ON_FLUSH_ENABLED, this::setMergeOnFlushEnabled);
+        scopedSettings.addSettingsUpdateConsumer(INDEX_MERGE_ON_FLUSH_POLICY, this::setMergeOnFlushPolicy);
+        scopedSettings.addSettingsUpdateConsumer(DEFAULT_SEARCH_PIPELINE, this::setDefaultSearchPipeline);
+        scopedSettings.addSettingsUpdateConsumer(
+            INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING,
+            this::setRemoteTranslogUploadBufferInterval
+        );
     }
 
     private void setSearchIdleAfter(TimeValue searchIdleAfter) {
+        if (this.replicationType == ReplicationType.SEGMENT && this.getNumberOfReplicas() > 0) {
+            logger.warn("Search idle is not supported for indices with replicas using 'replication.type: SEGMENT'");
+        }
         this.searchIdleAfter = searchIdleAfter;
     }
 
@@ -835,7 +1093,7 @@ public String getUUID() {
      * Returns <code>true</code> if the index has a custom data path
      */
     public boolean hasCustomDataPath() {
-        return Strings.isNotEmpty(customDataPath());
+        return Strings.isEmpty(customDataPath()) == false;
     }
 
     /**
@@ -847,7 +1105,7 @@ public String customDataPath() {
 
     /**
      * Returns the version the index was created on.
-     * @see Version#indexCreated(Settings)
+     * @see IndexMetadata#indexCreated(Settings)
      */
     public Version getIndexVersionCreated() {
         return version;
@@ -881,6 +1139,65 @@ public int getNumberOfReplicas() {
         return settings.getAsInt(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, null);
     }
 
+    /**
+     * Returns true if segment replication is enabled on the index.
+     */
+    public boolean isSegRepEnabled() {
+        return ReplicationType.SEGMENT.equals(replicationType);
+    }
+
+    public boolean isSegRepLocalEnabled() {
+        return isSegRepEnabled() && !isRemoteStoreEnabled();
+    }
+
+    public boolean isSegRepWithRemoteEnabled() {
+        return isSegRepEnabled() && isRemoteStoreEnabled();
+    }
+
+    /**
+     * Returns if remote store is enabled for this index.
+     */
+    public boolean isRemoteStoreEnabled() {
+        return isRemoteStoreEnabled;
+    }
+
+    /**
+     * Returns remote store repository configured for this index.
+     */
+    public String getRemoteStoreRepository() {
+        return remoteStoreRepository;
+    }
+
+    /**
+     * Returns if remote translog store is enabled for this index.
+     */
+    public boolean isRemoteTranslogStoreEnabled() {
+        // Today enabling remote store automatically enables remote translog as well.
+        // which is why isRemoteStoreEnabled is used to represent isRemoteTranslogStoreEnabled
+        return isRemoteStoreEnabled;
+    }
+
+    /**
+     * Returns true if this is remote/searchable snapshot
+     */
+    public boolean isRemoteSnapshot() {
+        return isRemoteSnapshot;
+    }
+
+    /**
+     * If this is a remote snapshot and the extended compatibility
+     * feature flag is enabled, this returns the minimum {@link Version}
+     * supported. In all other cases, the return value is the
+     * {@link Version#minimumIndexCompatibilityVersion()} of {@link Version#CURRENT}.
+     */
+    public Version getExtendedCompatibilitySnapshotVersion() {
+        return extendedCompatibilitySnapshotVersion;
+    }
+
+    public String getRemoteStoreTranslogRepository() {
+        return remoteStoreTranslogRepository;
+    }
+
     /**
      * Returns the node settings. The settings returned from {@link #getSettings()} are a merged version of the
      * index settings and the node settings where node settings are overwritten by index settings.
@@ -897,9 +1214,9 @@ public Settings getNodeSettings() {
      */
     public synchronized boolean updateIndexMetadata(IndexMetadata indexMetadata) {
         final Settings newSettings = indexMetadata.getSettings();
-        if (version.equals(Version.indexCreated(newSettings)) == false) {
+        if (version.equals(IndexMetadata.indexCreated(newSettings)) == false) {
             throw new IllegalArgumentException(
-                "version mismatch on settings update expected: " + version + " but was: " + Version.indexCreated(newSettings)
+                "version mismatch on settings update expected: " + version + " but was: " + IndexMetadata.indexCreated(newSettings)
             );
         }
         final String newUUID = newSettings.get(IndexMetadata.SETTING_INDEX_UUID, IndexMetadata.INDEX_UUID_NA_VALUE);
@@ -931,7 +1248,9 @@ public synchronized boolean updateIndexMetadata(IndexMetadata indexMetadata) {
      */
     public static boolean same(final Settings left, final Settings right) {
         return left.filter(IndexScopedSettings.INDEX_SETTINGS_KEY_PREDICATE)
-            .equals(right.filter(IndexScopedSettings.INDEX_SETTINGS_KEY_PREDICATE));
+            .equals(right.filter(IndexScopedSettings.INDEX_SETTINGS_KEY_PREDICATE))
+            && left.filter(IndexScopedSettings.ARCHIVED_SETTINGS_KEY_PREDICATE)
+                .equals(right.filter(IndexScopedSettings.ARCHIVED_SETTINGS_KEY_PREDICATE));
     }
 
     /**
@@ -968,6 +1287,26 @@ public void setTranslogSyncInterval(TimeValue translogSyncInterval) {
         this.syncInterval = translogSyncInterval;
     }
 
+    /**
+     * Returns the translog sync/upload buffer interval when remote translog store is enabled and index setting
+     * {@code index.translog.durability} is set as {@code request}.
+     * @return the buffer interval.
+     */
+    public TimeValue getRemoteTranslogUploadBufferInterval() {
+        return remoteTranslogUploadBufferInterval;
+    }
+
+    /**
+     * Returns true iff the remote translog buffer interval setting exists or in other words is explicitly set.
+     */
+    public boolean isRemoteTranslogBufferIntervalExplicit() {
+        return INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.exists(settings);
+    }
+
+    public void setRemoteTranslogUploadBufferInterval(TimeValue remoteTranslogUploadBufferInterval) {
+        this.remoteTranslogUploadBufferInterval = remoteTranslogUploadBufferInterval;
+    }
+
     /**
      * Returns this interval in which the shards of this index are asynchronously refreshed. {@code -1} means async refresh is disabled.
      */
@@ -1176,9 +1515,43 @@ public long getGcDeletesInMillis() {
 
     /**
      * Returns the merge policy that should be used for this index.
-     */
-    public MergePolicy getMergePolicy() {
-        return mergePolicyConfig.getMergePolicy();
+     * @param isTimeSeriesIndex true if index contains @timestamp field
+     */
+    public MergePolicy getMergePolicy(boolean isTimeSeriesIndex) {
+        String indexScopedPolicy = scopedSettings.get(INDEX_MERGE_POLICY);
+        MergePolicyProvider mergePolicyProvider = null;
+        IndexMergePolicy indexMergePolicy = IndexMergePolicy.fromString(indexScopedPolicy);
+        switch (indexMergePolicy) {
+            case TIERED:
+                mergePolicyProvider = tieredMergePolicyProvider;
+                break;
+            case LOG_BYTE_SIZE:
+                mergePolicyProvider = logByteSizeMergePolicyProvider;
+                break;
+            case DEFAULT_POLICY:
+                if (isTimeSeriesIndex) {
+                    String nodeScopedTimeSeriesIndexPolicy = TIME_SERIES_INDEX_MERGE_POLICY.get(nodeSettings);
+                    IndexMergePolicy nodeMergePolicy = IndexMergePolicy.fromString(nodeScopedTimeSeriesIndexPolicy);
+                    switch (nodeMergePolicy) {
+                        case TIERED:
+                        case DEFAULT_POLICY:
+                            mergePolicyProvider = tieredMergePolicyProvider;
+                            break;
+                        case LOG_BYTE_SIZE:
+                            mergePolicyProvider = logByteSizeMergePolicyProvider;
+                            break;
+                    }
+                } else {
+                    mergePolicyProvider = tieredMergePolicyProvider;
+                }
+                break;
+        }
+        assert mergePolicyProvider != null : "should not happen as validation for invalid merge policy values "
+            + "are part of setting definition";
+        if (logger.isTraceEnabled()) {
+            logger.trace("Index: " + this.index.getName() + ", Merge policy used: " + mergePolicyProvider);
+        }
+        return mergePolicyProvider.getMergePolicy();
     }
 
     public <T> T getValue(Setting<T> setting) {
@@ -1207,6 +1580,17 @@ private void setMaxSlicesPerScroll(int value) {
         this.maxSlicesPerScroll = value;
     }
 
+    /**
+     * The maximum number of slices allowed in a PIT request.
+     */
+    public int getMaxSlicesPerPit() {
+        return maxSlicesPerPit;
+    }
+
+    private void setMaxSlicesPerPit(int value) {
+        this.maxSlicesPerPit = value;
+    }
+
     /**
      * The maximum length of regex string allowed in a regexp query.
      */
@@ -1289,6 +1673,18 @@ private void setSearchThrottled(boolean searchThrottled) {
         this.searchThrottled = searchThrottled;
     }
 
+    /**
+     * Returns true if unreferenced files should be cleaned up on merge failure for this index.
+     *
+     */
+    public boolean shouldCleanupUnreferencedFiles() {
+        return shouldCleanupUnreferencedFiles;
+    }
+
+    private void setShouldCleanupUnreferencedFiles(boolean shouldCleanupUnreferencedFiles) {
+        this.shouldCleanupUnreferencedFiles = shouldCleanupUnreferencedFiles;
+    }
+
     public long getMappingNestedFieldsLimit() {
         return mappingNestedFieldsLimit;
     }
@@ -1328,4 +1724,59 @@ public long getMappingFieldNameLengthLimit() {
     private void setMappingFieldNameLengthLimit(long value) {
         this.mappingFieldNameLengthLimit = value;
     }
+
+    private void setMaxFullFlushMergeWaitTime(TimeValue timeValue) {
+        this.maxFullFlushMergeWaitTime = timeValue;
+    }
+
+    private void setMergeOnFlushEnabled(boolean enabled) {
+        this.mergeOnFlushEnabled = enabled;
+    }
+
+    public TimeValue getMaxFullFlushMergeWaitTime() {
+        return this.maxFullFlushMergeWaitTime;
+    }
+
+    public boolean isMergeOnFlushEnabled() {
+        return mergeOnFlushEnabled;
+    }
+
+    private void setMergeOnFlushPolicy(String policy) {
+        if (Strings.isEmpty(policy) || DEFAULT_POLICY.equalsIgnoreCase(policy)) {
+            mergeOnFlushPolicy = null;
+        } else if (MERGE_ON_FLUSH_MERGE_POLICY.equalsIgnoreCase(policy)) {
+            this.mergeOnFlushPolicy = MergeOnFlushMergePolicy::new;
+        } else {
+            throw new IllegalArgumentException(
+                "The "
+                    + IndexSettings.INDEX_MERGE_ON_FLUSH_POLICY.getKey()
+                    + " has unsupported policy specified: "
+                    + policy
+                    + ". Please use one of: "
+                    + DEFAULT_POLICY
+                    + ", "
+                    + MERGE_ON_FLUSH_MERGE_POLICY
+            );
+        }
+    }
+
+    public Optional<UnaryOperator<MergePolicy>> getMergeOnFlushPolicy() {
+        return Optional.ofNullable(mergeOnFlushPolicy);
+    }
+
+    public String getDefaultSearchPipeline() {
+        return defaultSearchPipeline;
+    }
+
+    public void setDefaultSearchPipeline(String defaultSearchPipeline) {
+        this.defaultSearchPipeline = defaultSearchPipeline;
+    }
+
+    /**
+     * Returns true if we need to maintain backward compatibility for index sorted indices created prior to version 2.7
+     * @return boolean
+     */
+    public boolean shouldWidenIndexSortType() {
+        return this.widenIndexSortType;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/IndexSortConfig.java b/server/src/main/java/org/opensearch/index/IndexSortConfig.java
index 99cf5d2d6091c..763ed34a1e6a6 100644
--- a/server/src/main/java/org/opensearch/index/IndexSortConfig.java
+++ b/server/src/main/java/org/opensearch/index/IndexSortConfig.java
@@ -69,6 +69,7 @@
  *     </li>
  * </ul>
  *
+ * @opensearch.internal
 **/
 public final class IndexSortConfig {
     /**
@@ -199,6 +200,7 @@ public boolean hasPrimarySortOnField(String field) {
      * or returns null if this index has no sort.
      */
     public Sort buildIndexSort(
+        boolean shouldWidenIndexSortType,
         Function<String, MappedFieldType> fieldTypeLookup,
         BiFunction<MappedFieldType, Supplier<SearchLookup>, IndexFieldData<?>> fieldDataLookup
     ) {
@@ -220,17 +222,20 @@ public Sort buildIndexSort(
             }
             IndexFieldData<?> fieldData;
             try {
-                fieldData = fieldDataLookup.apply(
-                    ft,
-                    () -> { throw new UnsupportedOperationException("index sorting not supported on runtime field [" + ft.name() + "]"); }
-                );
+                fieldData = fieldDataLookup.apply(ft, () -> {
+                    throw new UnsupportedOperationException("index sorting not supported on runtime field [" + ft.name() + "]");
+                });
             } catch (Exception e) {
                 throw new IllegalArgumentException("docvalues not found for index sort field:[" + sortSpec.field + "]", e);
             }
             if (fieldData == null) {
                 throw new IllegalArgumentException("docvalues not found for index sort field:[" + sortSpec.field + "]");
             }
-            sortFields[i] = fieldData.sortField(sortSpec.missingValue, mode, null, reverse);
+            if (shouldWidenIndexSortType == true) {
+                sortFields[i] = fieldData.wideSortField(sortSpec.missingValue, mode, null, reverse);
+            } else {
+                sortFields[i] = fieldData.sortField(sortSpec.missingValue, mode, null, reverse);
+            }
             validateIndexSortField(sortFields[i]);
         }
         return new Sort(sortFields);
@@ -243,6 +248,11 @@ private void validateIndexSortField(SortField sortField) {
         }
     }
 
+    /**
+     * Field sort specification
+     *
+     * @opensearch.internal
+     */
     static class FieldSortSpec {
         final String field;
         SortOrder order;
diff --git a/server/src/main/java/org/opensearch/index/IndexWarmer.java b/server/src/main/java/org/opensearch/index/IndexWarmer.java
index 8a728101fb78c..b62afe6b6dcfc 100644
--- a/server/src/main/java/org/opensearch/index/IndexWarmer.java
+++ b/server/src/main/java/org/opensearch/index/IndexWarmer.java
@@ -54,6 +54,11 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * The main opensearch index warmer
+ *
+ * @opensearch.internal
+ */
 public final class IndexWarmer {
 
     private static final Logger logger = LogManager.getLogger(IndexWarmer.class);
@@ -103,7 +108,11 @@ void warm(OpenSearchDirectoryReader reader, IndexShard shard, IndexSettings sett
         }
     }
 
-    /** A handle on the execution of  warm-up action. */
+    /**
+     * A handle on the execution of  warm-up action.
+     *
+     * @opensearch.internal
+     */
     public interface TerminationHandle {
 
         TerminationHandle NO_WAIT = () -> {};
@@ -112,12 +121,22 @@ public interface TerminationHandle {
         void awaitTermination() throws InterruptedException;
     }
 
+    /**
+     * Listener for the index warmer
+     *
+     * @opensearch.internal
+     */
     public interface Listener {
         /** Queue tasks to warm-up the given segments and return handles that allow to wait for termination of the
          *  execution of those tasks. */
         TerminationHandle warmReader(IndexShard indexShard, OpenSearchDirectoryReader reader);
     }
 
+    /**
+     * Warmer for field data
+     *
+     * @opensearch.internal
+     */
     private static class FieldDataWarmer implements IndexWarmer.Listener {
 
         private final Executor executor;
@@ -147,7 +166,9 @@ public TerminationHandle warmReader(final IndexShard indexShard, final OpenSearc
                         IndexFieldData.Global<?> ifd = indexFieldDataService.getForField(
                             fieldType,
                             indexFieldDataService.index().getName(),
-                            () -> { throw new UnsupportedOperationException("search lookup not available when warming an index"); }
+                            () -> {
+                                throw new UnsupportedOperationException("search lookup not available when warming an index");
+                            }
                         );
                         IndexFieldData<?> global = ifd.loadGlobal(reader);
                         if (reader.leaves().isEmpty() == false) {
diff --git a/server/src/main/java/org/opensearch/index/IndexingPressure.java b/server/src/main/java/org/opensearch/index/IndexingPressure.java
index af5c1827e3c6b..4e55c941cb684 100644
--- a/server/src/main/java/org/opensearch/index/IndexingPressure.java
+++ b/server/src/main/java/org/opensearch/index/IndexingPressure.java
@@ -38,13 +38,18 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.stats.IndexingPressureStats;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 
+/**
+ * Tracks indexing memory pressure
+ *
+ * @opensearch.internal
+ */
 public class IndexingPressure {
 
     public static final Setting<ByteSizeValue> MAX_INDEXING_BYTES = Setting.memorySizeSetting(
diff --git a/server/src/main/java/org/opensearch/index/IndexingPressureService.java b/server/src/main/java/org/opensearch/index/IndexingPressureService.java
index 9044c5942e8cb..70fb5692f5619 100644
--- a/server/src/main/java/org/opensearch/index/IndexingPressureService.java
+++ b/server/src/main/java/org/opensearch/index/IndexingPressureService.java
@@ -9,7 +9,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.index.stats.ShardIndexingPressureStats;
 
@@ -18,6 +18,8 @@
 /**
  * Sets up classes for node/shard level indexing pressure.
  * Provides abstraction and orchestration for indexing pressure interfaces when called from Transport Actions or for Stats.
+ *
+ * @opensearch.internal
  */
 public class IndexingPressureService {
 
diff --git a/server/src/main/java/org/opensearch/index/IndexingSlowLog.java b/server/src/main/java/org/opensearch/index/IndexingSlowLog.java
index b77e7639152fb..2ef4552103008 100644
--- a/server/src/main/java/org/opensearch/index/IndexingSlowLog.java
+++ b/server/src/main/java/org/opensearch/index/IndexingSlowLog.java
@@ -36,17 +36,18 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.util.StringBuilders;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
-import org.opensearch.common.logging.OpenSearchLogMessage;
 import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.logging.OpenSearchLogMessage;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.shard.IndexingOperationListener;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -55,6 +56,11 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * The indexing slowlog implementation
+ *
+ * @opensearch.internal
+ */
 public final class IndexingSlowLog implements IndexingOperationListener {
     public static final String INDEX_INDEXING_SLOWLOG_PREFIX = "index.indexing.slowlog";
     public static final Setting<TimeValue> INDEX_INDEXING_SLOWLOG_THRESHOLD_INDEX_WARN_SETTING = Setting.timeSetting(
@@ -206,6 +212,11 @@ public void postIndex(ShardId shardId, Engine.Index indexOperation, Engine.Index
         }
     }
 
+    /**
+     * Slow log message for indexing
+     *
+     * @opensearch.internal
+     */
     static final class IndexingSlowLogMessage extends OpenSearchLogMessage {
 
         IndexingSlowLogMessage(Index index, ParsedDocument doc, long tookInNanos, boolean reformat, int maxSourceCharsToLog) {
@@ -233,7 +244,7 @@ private static Map<String, Object> prepareMap(
                 return map;
             }
             try {
-                String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getXContentType());
+                String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getMediaType());
                 String trim = Strings.cleanTruncate(source, maxSourceCharsToLog).trim();
                 StringBuilder sb = new StringBuilder(trim);
                 StringBuilders.escapeJson(sb, 0);
@@ -268,7 +279,7 @@ private static String message(Index index, ParsedDocument doc, long tookInNanos,
                 return sb.toString();
             }
             try {
-                String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getXContentType());
+                String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getMediaType());
                 sb.append(", source[").append(Strings.cleanTruncate(source, maxSourceCharsToLog).trim()).append("]");
             } catch (IOException e) {
                 sb.append(", source[_failed_to_convert_[").append(e.getMessage()).append("]]");
diff --git a/server/src/main/java/org/opensearch/index/IndicesModuleRequest.java b/server/src/main/java/org/opensearch/index/IndicesModuleRequest.java
new file mode 100644
index 0000000000000..f07aa01cf05f9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/IndicesModuleRequest.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Request for onIndexModule extension point
+ *
+ * @opensearch.internal
+ */
+public class IndicesModuleRequest extends TransportRequest {
+    private final Index index;
+    private final Settings indexSettings;
+
+    public IndicesModuleRequest(IndexModule indexModule) {
+        this.index = indexModule.getIndex();
+        this.indexSettings = indexModule.getSettings();
+    }
+
+    public IndicesModuleRequest(StreamInput in) throws IOException {
+        super(in);
+        this.index = new Index(in);
+        this.indexSettings = Settings.readSettingsFromStream(in);
+    }
+
+    public IndicesModuleRequest(Index index, Settings settings) {
+        this.index = index;
+        this.indexSettings = settings;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        index.writeTo(out);
+        Settings.writeSettingsToStream(indexSettings, out);
+    }
+
+    @Override
+    public String toString() {
+        return "IndicesModuleRequest{" + "index=" + index + ", indexSettings=" + indexSettings + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        IndicesModuleRequest that = (IndicesModuleRequest) o;
+        return Objects.equals(index, that.index) && Objects.equals(indexSettings, that.indexSettings);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(index, indexSettings);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/IndicesModuleResponse.java b/server/src/main/java/org/opensearch/index/IndicesModuleResponse.java
new file mode 100644
index 0000000000000..3d2340ed35a8c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/IndicesModuleResponse.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Response for onIndexModule extension point
+ *
+ * @opensearch.internal
+ */
+public class IndicesModuleResponse extends TransportResponse {
+    private boolean supportsIndexEventListener;
+    private boolean addIndexOperationListener;
+    private boolean addSearchOperationListener;
+
+    public IndicesModuleResponse(
+        boolean supportsIndexEventListener,
+        boolean addIndexOperationListener,
+        boolean addSearchOperationListener
+    ) {
+        this.supportsIndexEventListener = supportsIndexEventListener;
+        this.addIndexOperationListener = addIndexOperationListener;
+        this.addSearchOperationListener = addSearchOperationListener;
+    }
+
+    public IndicesModuleResponse(StreamInput in) throws IOException {
+        this.supportsIndexEventListener = in.readBoolean();
+        this.addIndexOperationListener = in.readBoolean();
+        this.addSearchOperationListener = in.readBoolean();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeBoolean(supportsIndexEventListener);
+        out.writeBoolean(addIndexOperationListener);
+        out.writeBoolean(addSearchOperationListener);
+    }
+
+    public boolean getIndexEventListener() {
+        return this.supportsIndexEventListener;
+    }
+
+    public boolean getIndexOperationListener() {
+        return this.addIndexOperationListener;
+    }
+
+    public boolean getSearchOperationListener() {
+        return this.addSearchOperationListener;
+    }
+
+    @Override
+    public String toString() {
+        return "IndicesModuleResponse{"
+            + "supportsIndexEventListener"
+            + supportsIndexEventListener
+            + " addIndexOperationListener"
+            + addIndexOperationListener
+            + " addSearchOperationListener"
+            + addSearchOperationListener
+            + "}";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        IndicesModuleResponse that = (IndicesModuleResponse) o;
+        return Objects.equals(supportsIndexEventListener, that.supportsIndexEventListener)
+            && Objects.equals(addIndexOperationListener, that.addIndexOperationListener)
+            && Objects.equals(addSearchOperationListener, that.addSearchOperationListener);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(supportsIndexEventListener, addIndexOperationListener, addSearchOperationListener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java b/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java
new file mode 100644
index 0000000000000..0b762d781957c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/LogByteSizeMergePolicyProvider.java
@@ -0,0 +1,166 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.index.LogByteSizeMergePolicy;
+import org.apache.lucene.index.MergePolicy;
+import org.apache.lucene.index.NoMergePolicy;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+
+import static org.apache.lucene.index.LogMergePolicy.DEFAULT_MAX_MERGE_DOCS;
+import static org.apache.lucene.index.LogMergePolicy.DEFAULT_NO_CFS_RATIO;
+
+/**
+ * <p>
+ * The LogByteSizeMergePolicy is an alternative merge policy primarily used here to optimize the merging of segments in scenarios
+ * with index with timestamps.
+ * While the TieredMergePolicy is the default choice, the LogByteSizeMergePolicy can be configured
+ * as the default merge policy for time-index data using the <code>index.datastream_merge.policy</code> setting.
+ *
+ * <p>
+ * Unlike the TieredMergePolicy, which prioritizes merging segments of equal sizes, the LogByteSizeMergePolicy
+ * specializes in merging adjacent segments efficiently.
+ * This characteristic makes it particularly well-suited for range queries on time-index data.
+ * Typically, adjacent segments in time-index data often contain documents with similar timestamps.
+ * When these segments are merged, the resulting segment covers a range of timestamps with reduced overlap compared
+ * to the adjacent segments. This reduced overlap remains even as segments grow older and larger,
+ * which can significantly benefit range queries on timestamps.
+ *
+ * <p>
+ * In contrast, the TieredMergePolicy does not honor this timestamp range optimization. It focuses on merging segments
+ * of equal sizes and does not consider adjacency. Consequently, as segments grow older and larger,
+ * the overlap of timestamp ranges among adjacent segments managed by TieredMergePolicy can increase.
+ * This can lead to inefficiencies in range queries on timestamps, as the number of segments to be scanned
+ * within a given timestamp range could become high.
+ *
+ * @opensearch.internal
+ */
+public class LogByteSizeMergePolicyProvider implements MergePolicyProvider {
+    private final LogByteSizeMergePolicy logByteSizeMergePolicy = new LogByteSizeMergePolicy();
+
+    private final Logger logger;
+    private final boolean mergesEnabled;
+
+    public static final ByteSizeValue DEFAULT_MIN_MERGE = new ByteSizeValue(2, ByteSizeUnit.MB);
+    public static final int DEFAULT_MERGE_FACTOR = 10;
+
+    public static final ByteSizeValue DEFAULT_MAX_MERGED_SEGMENT = new ByteSizeValue(5, ByteSizeUnit.GB);
+
+    public static final ByteSizeValue DEFAULT_MAX_MERGE_SEGMENT_FORCE_MERGE = new ByteSizeValue(Long.MAX_VALUE);
+
+    public static final Setting<Integer> INDEX_LBS_MERGE_POLICY_MERGE_FACTOR_SETTING = Setting.intSetting(
+        "index.merge.log_byte_size_policy.merge_factor",
+        DEFAULT_MERGE_FACTOR, // keeping it same as default max merge at once for tiered merge policy
+        2,
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    public static final Setting<ByteSizeValue> INDEX_LBS_MERGE_POLICY_MIN_MERGE_SETTING = Setting.byteSizeSetting(
+        "index.merge.log_byte_size_policy.min_merge",
+        DEFAULT_MIN_MERGE, // keeping it same as default floor segment for tiered merge policy
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    public static final Setting<ByteSizeValue> INDEX_LBS_MAX_MERGE_SEGMENT_SETTING = Setting.byteSizeSetting(
+        "index.merge.log_byte_size_policy.max_merge_segment",
+        DEFAULT_MAX_MERGED_SEGMENT, // keeping default same as tiered merge policy
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    public static final Setting<ByteSizeValue> INDEX_LBS_MAX_MERGE_SEGMENT_FOR_FORCED_MERGE_SETTING = Setting.byteSizeSetting(
+        "index.merge.log_byte_size_policy.max_merge_segment_forced_merge",
+        DEFAULT_MAX_MERGE_SEGMENT_FORCE_MERGE,
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    public static final Setting<Integer> INDEX_LBS_MAX_MERGED_DOCS_SETTING = Setting.intSetting(
+        "index.merge.log_byte_size_policy.max_merged_docs",
+        DEFAULT_MAX_MERGE_DOCS,
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    public static final Setting<Double> INDEX_LBS_NO_CFS_RATIO_SETTING = new Setting<>(
+        "index.merge.log_byte_size_policy.no_cfs_ratio",
+        Double.toString(DEFAULT_NO_CFS_RATIO),
+        TieredMergePolicyProvider::parseNoCFSRatio,
+        Setting.Property.Dynamic,
+        Setting.Property.IndexScope
+    );
+
+    LogByteSizeMergePolicyProvider(Logger logger, IndexSettings indexSettings) {
+        this.logger = logger;
+        this.mergesEnabled = indexSettings.getSettings().getAsBoolean(INDEX_MERGE_ENABLED, true);
+
+        // Undocumented settings, works great with defaults
+        logByteSizeMergePolicy.setMergeFactor(indexSettings.getValue(INDEX_LBS_MERGE_POLICY_MERGE_FACTOR_SETTING));
+        logByteSizeMergePolicy.setMinMergeMB(indexSettings.getValue(INDEX_LBS_MERGE_POLICY_MIN_MERGE_SETTING).getMbFrac());
+        logByteSizeMergePolicy.setMaxMergeMB(indexSettings.getValue(INDEX_LBS_MAX_MERGE_SEGMENT_SETTING).getMbFrac());
+        logByteSizeMergePolicy.setMaxMergeMBForForcedMerge(
+            indexSettings.getValue(INDEX_LBS_MAX_MERGE_SEGMENT_FOR_FORCED_MERGE_SETTING).getMbFrac()
+        );
+        logByteSizeMergePolicy.setMaxMergeDocs(indexSettings.getValue(INDEX_LBS_MAX_MERGED_DOCS_SETTING));
+        logByteSizeMergePolicy.setNoCFSRatio(indexSettings.getValue(INDEX_LBS_NO_CFS_RATIO_SETTING));
+    }
+
+    @Override
+    public MergePolicy getMergePolicy() {
+        return mergesEnabled ? logByteSizeMergePolicy : NoMergePolicy.INSTANCE;
+    }
+
+    void setLBSMergeFactor(int mergeFactor) {
+        logByteSizeMergePolicy.setMergeFactor(mergeFactor);
+    }
+
+    void setLBSMaxMergeSegment(ByteSizeValue maxMergeSegment) {
+        logByteSizeMergePolicy.setMaxMergeMB(maxMergeSegment.getMbFrac());
+    }
+
+    void setLBSMinMergedMB(ByteSizeValue minMergedSize) {
+        logByteSizeMergePolicy.setMinMergeMB(minMergedSize.getMbFrac());
+    }
+
+    void setLBSMaxMergeMBForForcedMerge(ByteSizeValue maxMergeForcedMerge) {
+        logByteSizeMergePolicy.setMaxMergeMBForForcedMerge(maxMergeForcedMerge.getMbFrac());
+    }
+
+    void setLBSMaxMergeDocs(int maxMergeDocs) {
+        logByteSizeMergePolicy.setMaxMergeDocs(maxMergeDocs);
+    }
+
+    void setLBSNoCFSRatio(Double noCFSRatio) {
+        logByteSizeMergePolicy.setNoCFSRatio(noCFSRatio);
+    }
+
+    @Override
+    public String toString() {
+        return "LogByteSizeMergePolicyProvider{"
+            + "mergeFactor="
+            + logByteSizeMergePolicy.getMergeFactor()
+            + ", minMergeMB="
+            + logByteSizeMergePolicy.getMinMergeMB()
+            + ", maxMergeMB="
+            + logByteSizeMergePolicy.getMaxMergeMB()
+            + ", maxMergeMBForForcedMerge="
+            + logByteSizeMergePolicy.getMaxMergeMBForForcedMerge()
+            + ", maxMergedDocs="
+            + logByteSizeMergePolicy.getMaxMergeDocs()
+            + ", noCFSRatio="
+            + logByteSizeMergePolicy.getNoCFSRatio()
+            + '}';
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/MergePolicyConfig.java b/server/src/main/java/org/opensearch/index/MergePolicyConfig.java
deleted file mode 100644
index 26d2588e3f240..0000000000000
--- a/server/src/main/java/org/opensearch/index/MergePolicyConfig.java
+++ /dev/null
@@ -1,311 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.lucene.index.MergePolicy;
-import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.index.TieredMergePolicy;
-import org.opensearch.common.settings.Setting;
-import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-
-/**
- * A shard in opensearch is a Lucene index, and a Lucene index is broken
- * down into segments. Segments are internal storage elements in the index
- * where the index data is stored, and are immutable up to delete markers.
- * Segments are, periodically, merged into larger segments to keep the
- * index size at bay and expunge deletes.
- *
- * <p>
- * Merges select segments of approximately equal size, subject to an allowed
- * number of segments per tier. The merge policy is able to merge
- * non-adjacent segments, and separates how many segments are merged at once from how many
- * segments are allowed per tier. It also does not over-merge (i.e., cascade merges).
- *
- * <p>
- * All merge policy settings are <b>dynamic</b> and can be updated on a live index.
- * The merge policy has the following settings:
- *
- * <ul>
- * <li><code>index.merge.policy.expunge_deletes_allowed</code>:
- *
- *     When expungeDeletes is called, we only merge away a segment if its delete
- *     percentage is over this threshold. Default is <code>10</code>.
- *
- * <li><code>index.merge.policy.floor_segment</code>:
- *
- *     Segments smaller than this are "rounded up" to this size, i.e. treated as
- *     equal (floor) size for merge selection. This is to prevent frequent
- *     flushing of tiny segments, thus preventing a long tail in the index. Default
- *     is <code>2mb</code>.
- *
- * <li><code>index.merge.policy.max_merge_at_once</code>:
- *
- *     Maximum number of segments to be merged at a time during "normal" merging.
- *     Default is <code>10</code>.
- *
- * <li><code>index.merge.policy.max_merged_segment</code>:
- *
- *     Maximum sized segment to produce during normal merging (not explicit
- *     force merge). This setting is approximate: the estimate of the merged
- *     segment size is made by summing sizes of to-be-merged segments
- *     (compensating for percent deleted docs). Default is <code>5gb</code>.
- *
- * <li><code>index.merge.policy.segments_per_tier</code>:
- *
- *     Sets the allowed number of segments per tier. Smaller values mean more
- *     merging but fewer segments. Default is <code>10</code>. Note, this value needs to be
- *     &gt;= than the <code>max_merge_at_once</code> otherwise you'll force too many merges to
- *     occur.
- *
- * <li><code>index.merge.policy.deletes_pct_allowed</code>:
- *
- *     Controls the maximum percentage of deleted documents that is tolerated in
- *     the index. Lower values make the index more space efficient at the
- *     expense of increased CPU and I/O activity. Values must be between <code>20</code> and
- *     <code>50</code>. Default value is <code>33</code>.
- * </ul>
- *
- * <p>
- * For normal merging, the policy first computes a "budget" of how many
- * segments are allowed to be in the index. If the index is over-budget,
- * then the policy sorts segments by decreasing size (proportionally considering percent
- * deletes), and then finds the least-cost merge. Merge cost is measured by
- * a combination of the "skew" of the merge (size of largest seg divided by
- * smallest seg), total merge size and pct deletes reclaimed, so that
- * merges with lower skew, smaller size and those reclaiming more deletes,
- * are favored.
- *
- * <p>
- * If a merge will produce a segment that's larger than
- * <code>max_merged_segment</code> then the policy will merge fewer segments (down to
- * 1 at once, if that one has deletions) to keep the segment size under
- * budget.
- *
- * <p>
- * Note, this can mean that for large shards that holds many gigabytes of
- * data, the default of <code>max_merged_segment</code> (<code>5gb</code>) can cause for many
- * segments to be in an index, and causing searches to be slower. Use the
- * indices segments API to see the segments that an index has, and
- * possibly either increase the <code>max_merged_segment</code> or issue an optimize
- * call for the index (try and aim to issue it on a low traffic time).
- */
-
-public final class MergePolicyConfig {
-    private final OpenSearchTieredMergePolicy mergePolicy = new OpenSearchTieredMergePolicy();
-    private final Logger logger;
-    private final boolean mergesEnabled;
-
-    public static final double DEFAULT_EXPUNGE_DELETES_ALLOWED = 10d;
-    public static final ByteSizeValue DEFAULT_FLOOR_SEGMENT = new ByteSizeValue(2, ByteSizeUnit.MB);
-    public static final int DEFAULT_MAX_MERGE_AT_ONCE = 10;
-    public static final ByteSizeValue DEFAULT_MAX_MERGED_SEGMENT = new ByteSizeValue(5, ByteSizeUnit.GB);
-    public static final double DEFAULT_SEGMENTS_PER_TIER = 10.0d;
-    public static final double DEFAULT_RECLAIM_DELETES_WEIGHT = 2.0d;
-    public static final double DEFAULT_DELETES_PCT_ALLOWED = 33.0d;
-    public static final Setting<Double> INDEX_COMPOUND_FORMAT_SETTING = new Setting<>(
-        "index.compound_format",
-        Double.toString(TieredMergePolicy.DEFAULT_NO_CFS_RATIO),
-        MergePolicyConfig::parseNoCFSRatio,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-
-    public static final Setting<Double> INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING = Setting.doubleSetting(
-        "index.merge.policy.expunge_deletes_allowed",
-        DEFAULT_EXPUNGE_DELETES_ALLOWED,
-        0.0d,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    public static final Setting<ByteSizeValue> INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING = Setting.byteSizeSetting(
-        "index.merge.policy.floor_segment",
-        DEFAULT_FLOOR_SEGMENT,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    public static final Setting<Integer> INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING = Setting.intSetting(
-        "index.merge.policy.max_merge_at_once",
-        DEFAULT_MAX_MERGE_AT_ONCE,
-        2,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    public static final Setting<ByteSizeValue> INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING = Setting.byteSizeSetting(
-        "index.merge.policy.max_merged_segment",
-        DEFAULT_MAX_MERGED_SEGMENT,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    public static final Setting<Double> INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING = Setting.doubleSetting(
-        "index.merge.policy.segments_per_tier",
-        DEFAULT_SEGMENTS_PER_TIER,
-        2.0d,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    public static final Setting<Double> INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING = Setting.doubleSetting(
-        "index.merge.policy.reclaim_deletes_weight",
-        DEFAULT_RECLAIM_DELETES_WEIGHT,
-        0.0d,
-        Property.Dynamic,
-        Property.IndexScope,
-        Property.Deprecated
-    );
-    public static final Setting<Double> INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING = Setting.doubleSetting(
-        "index.merge.policy.deletes_pct_allowed",
-        DEFAULT_DELETES_PCT_ALLOWED,
-        20.0d,
-        50.0d,
-        Property.Dynamic,
-        Property.IndexScope
-    );
-    // don't convert to Setting<> and register... we only set this in tests and register via a plugin
-    public static final String INDEX_MERGE_ENABLED = "index.merge.enabled";
-
-    MergePolicyConfig(Logger logger, IndexSettings indexSettings) {
-        this.logger = logger;
-        double forceMergeDeletesPctAllowed = indexSettings.getValue(INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING); // percentage
-        ByteSizeValue floorSegment = indexSettings.getValue(INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING);
-        int maxMergeAtOnce = indexSettings.getValue(INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING);
-        // TODO is this really a good default number for max_merge_segment, what happens for large indices,
-        // won't they end up with many segments?
-        ByteSizeValue maxMergedSegment = indexSettings.getValue(INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING);
-        double segmentsPerTier = indexSettings.getValue(INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING);
-        double reclaimDeletesWeight = indexSettings.getValue(INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING);
-        double deletesPctAllowed = indexSettings.getValue(INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING);
-        this.mergesEnabled = indexSettings.getSettings().getAsBoolean(INDEX_MERGE_ENABLED, true);
-        if (mergesEnabled == false) {
-            logger.warn(
-                "[{}] is set to false, this should only be used in tests and can cause serious problems in production" + " environments",
-                INDEX_MERGE_ENABLED
-            );
-        }
-        maxMergeAtOnce = adjustMaxMergeAtOnceIfNeeded(maxMergeAtOnce, segmentsPerTier);
-        mergePolicy.setNoCFSRatio(indexSettings.getValue(INDEX_COMPOUND_FORMAT_SETTING));
-        mergePolicy.setForceMergeDeletesPctAllowed(forceMergeDeletesPctAllowed);
-        mergePolicy.setFloorSegmentMB(floorSegment.getMbFrac());
-        mergePolicy.setMaxMergeAtOnce(maxMergeAtOnce);
-        mergePolicy.setMaxMergedSegmentMB(maxMergedSegment.getMbFrac());
-        mergePolicy.setSegmentsPerTier(segmentsPerTier);
-        mergePolicy.setDeletesPctAllowed(deletesPctAllowed);
-        if (logger.isTraceEnabled()) {
-            logger.trace(
-                "using [tiered] merge mergePolicy with expunge_deletes_allowed[{}], floor_segment[{}],"
-                    + " max_merge_at_once[{}], max_merged_segment[{}], segments_per_tier[{}],"
-                    + " deletes_pct_allowed[{}]",
-                forceMergeDeletesPctAllowed,
-                floorSegment,
-                maxMergeAtOnce,
-                maxMergedSegment,
-                segmentsPerTier,
-                deletesPctAllowed
-            );
-        }
-    }
-
-    void setSegmentsPerTier(Double segmentsPerTier) {
-        mergePolicy.setSegmentsPerTier(segmentsPerTier);
-    }
-
-    void setMaxMergedSegment(ByteSizeValue maxMergedSegment) {
-        mergePolicy.setMaxMergedSegmentMB(maxMergedSegment.getMbFrac());
-    }
-
-    void setMaxMergesAtOnce(Integer maxMergeAtOnce) {
-        mergePolicy.setMaxMergeAtOnce(maxMergeAtOnce);
-    }
-
-    void setFloorSegmentSetting(ByteSizeValue floorSegementSetting) {
-        mergePolicy.setFloorSegmentMB(floorSegementSetting.getMbFrac());
-    }
-
-    void setExpungeDeletesAllowed(Double value) {
-        mergePolicy.setForceMergeDeletesPctAllowed(value);
-    }
-
-    void setNoCFSRatio(Double noCFSRatio) {
-        mergePolicy.setNoCFSRatio(noCFSRatio);
-    }
-
-    void setDeletesPctAllowed(Double deletesPctAllowed) {
-        mergePolicy.setDeletesPctAllowed(deletesPctAllowed);
-    }
-
-    private int adjustMaxMergeAtOnceIfNeeded(int maxMergeAtOnce, double segmentsPerTier) {
-        // fixing maxMergeAtOnce, see TieredMergePolicy#setMaxMergeAtOnce
-        if (!(segmentsPerTier >= maxMergeAtOnce)) {
-            int newMaxMergeAtOnce = (int) segmentsPerTier;
-            // max merge at once should be at least 2
-            if (newMaxMergeAtOnce <= 1) {
-                newMaxMergeAtOnce = 2;
-            }
-            logger.debug(
-                "changing max_merge_at_once from [{}] to [{}] because segments_per_tier [{}] has to be higher or " + "equal to it",
-                maxMergeAtOnce,
-                newMaxMergeAtOnce,
-                segmentsPerTier
-            );
-            maxMergeAtOnce = newMaxMergeAtOnce;
-        }
-        return maxMergeAtOnce;
-    }
-
-    MergePolicy getMergePolicy() {
-        return mergesEnabled ? mergePolicy : NoMergePolicy.INSTANCE;
-    }
-
-    private static double parseNoCFSRatio(String noCFSRatio) {
-        noCFSRatio = noCFSRatio.trim();
-        if (noCFSRatio.equalsIgnoreCase("true")) {
-            return 1.0d;
-        } else if (noCFSRatio.equalsIgnoreCase("false")) {
-            return 0.0;
-        } else {
-            try {
-                double value = Double.parseDouble(noCFSRatio);
-                if (value < 0.0 || value > 1.0) {
-                    throw new IllegalArgumentException("NoCFSRatio must be in the interval [0..1] but was: [" + value + "]");
-                }
-                return value;
-            } catch (NumberFormatException ex) {
-                throw new IllegalArgumentException(
-                    "Expected a boolean or a value in the interval [0..1] but was: " + "[" + noCFSRatio + "]",
-                    ex
-                );
-            }
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/index/MergePolicyProvider.java b/server/src/main/java/org/opensearch/index/MergePolicyProvider.java
new file mode 100644
index 0000000000000..6f734314f758f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/MergePolicyProvider.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.apache.lucene.index.MergePolicy;
+import org.opensearch.common.annotation.InternalApi;
+
+/**
+ * A provider for obtaining merge policies used by OpenSearch indexes.
+ *
+ * @opensearch.internal
+ */
+
+@InternalApi
+public interface MergePolicyProvider {
+    // don't convert to Setting<> and register... we only set this in tests and register via a plugin
+    String INDEX_MERGE_ENABLED = "index.merge.enabled";
+
+    /**
+     * Gets the merge policy to be used for index.
+     *
+     * @return The merge policy instance.
+     */
+    MergePolicy getMergePolicy();
+}
diff --git a/server/src/main/java/org/opensearch/index/MergeSchedulerConfig.java b/server/src/main/java/org/opensearch/index/MergeSchedulerConfig.java
index df3c76fea0ea6..9e170b448d641 100644
--- a/server/src/main/java/org/opensearch/index/MergeSchedulerConfig.java
+++ b/server/src/main/java/org/opensearch/index/MergeSchedulerConfig.java
@@ -63,6 +63,8 @@
  *     throttled, while an application doing heavy indexing will see the throttle
  *     move higher to allow merges to keep up with ongoing indexing.
  * </ul>
+ *
+ * @opensearch.internal
  */
 public final class MergeSchedulerConfig {
 
diff --git a/server/src/main/java/org/opensearch/index/OpenSearchTieredMergePolicy.java b/server/src/main/java/org/opensearch/index/OpenSearchTieredMergePolicy.java
index 0289e96b356be..df1666e72f2ee 100644
--- a/server/src/main/java/org/opensearch/index/OpenSearchTieredMergePolicy.java
+++ b/server/src/main/java/org/opensearch/index/OpenSearchTieredMergePolicy.java
@@ -42,8 +42,10 @@
 
 /**
  * Wrapper around {@link TieredMergePolicy} which doesn't respect
- * {@link TieredMergePolicy#setMaxMergedSegmentMB(double)} on forced merges.
+ * {@link TieredMergePolicy#setMaxMergedSegmentMB(double)} on forced merges, but DOES respect it on only_expunge_deletes.
  * See https://issues.apache.org/jira/browse/LUCENE-7976.
+ *
+ * @opensearch.internal
  */
 final class OpenSearchTieredMergePolicy extends FilterMergePolicy {
 
@@ -69,7 +71,7 @@ public MergeSpecification findForcedMerges(
 
     @Override
     public MergeSpecification findForcedDeletesMerges(SegmentInfos infos, MergeContext mergeContext) throws IOException {
-        return forcedMergePolicy.findForcedDeletesMerges(infos, mergeContext);
+        return regularMergePolicy.findForcedDeletesMerges(infos, mergeContext);
     }
 
     public void setForceMergeDeletesPctAllowed(double forceMergeDeletesPctAllowed) {
@@ -78,7 +80,7 @@ public void setForceMergeDeletesPctAllowed(double forceMergeDeletesPctAllowed) {
     }
 
     public double getForceMergeDeletesPctAllowed() {
-        return forcedMergePolicy.getForceMergeDeletesPctAllowed();
+        return regularMergePolicy.getForceMergeDeletesPctAllowed();
     }
 
     public void setFloorSegmentMB(double mbFrac) {
diff --git a/server/src/main/java/org/opensearch/index/ReplicationStats.java b/server/src/main/java/org/opensearch/index/ReplicationStats.java
new file mode 100644
index 0000000000000..9cc6685c75f80
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/ReplicationStats.java
@@ -0,0 +1,97 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * ReplicationStats is used to provide segment replication statistics at an index,
+ * node and cluster level on a segment replication enabled cluster.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationStats implements ToXContentFragment, Writeable {
+
+    public long maxBytesBehind;
+    public long maxReplicationLag;
+    public long totalBytesBehind;
+
+    public ReplicationStats(long maxBytesBehind, long totalBytesBehind, long maxReplicationLag) {
+        this.maxBytesBehind = maxBytesBehind;
+        this.totalBytesBehind = totalBytesBehind;
+        this.maxReplicationLag = maxReplicationLag;
+    }
+
+    public ReplicationStats(StreamInput in) throws IOException {
+        this.maxBytesBehind = in.readVLong();
+        this.totalBytesBehind = in.readVLong();
+        this.maxReplicationLag = in.readVLong();
+    }
+
+    public ReplicationStats() {
+
+    }
+
+    public void add(ReplicationStats other) {
+        if (other != null) {
+            maxBytesBehind = Math.max(other.maxBytesBehind, maxBytesBehind);
+            totalBytesBehind += other.totalBytesBehind;
+            maxReplicationLag = Math.max(other.maxReplicationLag, maxReplicationLag);
+        }
+    }
+
+    public long getMaxBytesBehind() {
+        return this.maxBytesBehind;
+    }
+
+    public long getTotalBytesBehind() {
+        return this.totalBytesBehind;
+    }
+
+    public long getMaxReplicationLag() {
+        return this.maxReplicationLag;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(maxBytesBehind);
+        out.writeVLong(totalBytesBehind);
+        out.writeVLong(maxReplicationLag);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(Fields.SEGMENT_REPLICATION);
+        builder.field(Fields.MAX_BYTES_BEHIND, new ByteSizeValue(maxBytesBehind).toString());
+        builder.field(Fields.TOTAL_BYTES_BEHIND, new ByteSizeValue(totalBytesBehind).toString());
+        builder.field(Fields.MAX_REPLICATION_LAG, new TimeValue(maxReplicationLag));
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * Fields for segment replication statistics
+     *
+     * @opensearch.internal
+     */
+    static final class Fields {
+        static final String SEGMENT_REPLICATION = "segment_replication";
+        static final String MAX_BYTES_BEHIND = "max_bytes_behind";
+        static final String TOTAL_BYTES_BEHIND = "total_bytes_behind";
+        static final String MAX_REPLICATION_LAG = "max_replication_lag";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/SearchSlowLog.java b/server/src/main/java/org/opensearch/index/SearchSlowLog.java
index 37413388215c8..d8bcd6c848cef 100644
--- a/server/src/main/java/org/opensearch/index/SearchSlowLog.java
+++ b/server/src/main/java/org/opensearch/index/SearchSlowLog.java
@@ -33,15 +33,16 @@
 package org.opensearch.index;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.Strings;
-import org.opensearch.common.logging.OpenSearchLogMessage;
 import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.logging.OpenSearchLogMessage;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.index.shard.SearchOperationListener;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.tasks.Task;
@@ -53,6 +54,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
+/**
+ * The search time slow log implementation
+ *
+ * @opensearch.internal
+ */
 public final class SearchSlowLog implements SearchOperationListener {
     private static final Charset UTF_8 = Charset.forName("UTF-8");
 
@@ -203,6 +209,11 @@ public void onFetchPhase(SearchContext context, long tookInNanos) {
         }
     }
 
+    /**
+     * Search slow log message
+     *
+     * @opensearch.internal
+     */
     static final class SearchSlowLogMessage extends OpenSearchLogMessage {
 
         SearchSlowLogMessage(SearchContext context, long tookInNanos) {
diff --git a/server/src/main/java/org/opensearch/index/SegmentReplicationPerGroupStats.java b/server/src/main/java/org/opensearch/index/SegmentReplicationPerGroupStats.java
new file mode 100644
index 0000000000000..c3b4f8217c961
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/SegmentReplicationPerGroupStats.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Set;
+
+/**
+ * Return Segment Replication stats for a Replication Group.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationPerGroupStats implements Writeable, ToXContentFragment {
+
+    private final ShardId shardId;
+    private final Set<SegmentReplicationShardStats> replicaStats;
+    private final long rejectedRequestCount;
+
+    public SegmentReplicationPerGroupStats(ShardId shardId, Set<SegmentReplicationShardStats> replicaStats, long rejectedRequestCount) {
+        this.shardId = shardId;
+        this.replicaStats = replicaStats;
+        this.rejectedRequestCount = rejectedRequestCount;
+    }
+
+    public SegmentReplicationPerGroupStats(StreamInput in) throws IOException {
+        this.shardId = new ShardId(in);
+        this.replicaStats = in.readSet(SegmentReplicationShardStats::new);
+        this.rejectedRequestCount = in.readVLong();
+    }
+
+    public Set<SegmentReplicationShardStats> getReplicaStats() {
+        return replicaStats;
+    }
+
+    public long getRejectedRequestCount() {
+        return rejectedRequestCount;
+    }
+
+    public ShardId getShardId() {
+        return shardId;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field("rejected_requests", rejectedRequestCount);
+        builder.startArray("replicas");
+        for (SegmentReplicationShardStats stats : replicaStats) {
+            stats.toXContent(builder, params);
+        }
+        builder.endArray();
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        shardId.writeTo(out);
+        out.writeCollection(replicaStats);
+        out.writeVLong(rejectedRequestCount);
+    }
+
+    @Override
+    public String toString() {
+        return "SegmentReplicationPerGroupStats{" + "replicaStats=" + replicaStats + ", rejectedRequestCount=" + rejectedRequestCount + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/SegmentReplicationPressureService.java b/server/src/main/java/org/opensearch/index/SegmentReplicationPressureService.java
new file mode 100644
index 0000000000000..7afcb595cf4e7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/SegmentReplicationPressureService.java
@@ -0,0 +1,305 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.AbstractAsyncTask;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Comparator;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Service responsible for applying backpressure for lagging behind replicas when Segment Replication is enabled.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationPressureService implements Closeable {
+
+    private volatile boolean isSegmentReplicationBackpressureEnabled;
+    private volatile int maxCheckpointsBehind;
+    private volatile double maxAllowedStaleReplicas;
+    private volatile TimeValue replicationTimeLimitBackpressure;
+    private volatile TimeValue replicationTimeLimitFailReplica;
+
+    private static final Logger logger = LogManager.getLogger(SegmentReplicationPressureService.class);
+
+    /**
+     * When enabled, writes will be rejected when a replica shard falls behind by both the MAX_REPLICATION_TIME_SETTING time value and MAX_INDEXING_CHECKPOINTS number of checkpoints.
+     * Once a shard falls behind double the MAX_REPLICATION_TIME_SETTING time value it will be marked as failed.
+     */
+    public static final Setting<Boolean> SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED = Setting.boolSetting(
+        "segrep.pressure.enabled",
+        false,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Integer> MAX_INDEXING_CHECKPOINTS = Setting.intSetting(
+        "segrep.pressure.checkpoint.limit",
+        4,
+        1,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    // Time limit on max allowed replica staleness after which backpressure kicks in on primary.
+    public static final Setting<TimeValue> MAX_REPLICATION_TIME_BACKPRESSURE_SETTING = Setting.positiveTimeSetting(
+        "segrep.pressure.time.limit",
+        TimeValue.timeValueMinutes(5),
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    // Time limit on max allowed replica staleness after which we start failing the replica shard.
+    // Defaults to 0(disabled)
+    public static final Setting<TimeValue> MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING = Setting.positiveTimeSetting(
+        "segrep.replication.time.limit",
+        TimeValue.timeValueMinutes(0),
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Double> MAX_ALLOWED_STALE_SHARDS = Setting.doubleSetting(
+        "segrep.pressure.replica.stale.limit",
+        .5,
+        0,
+        1,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private final IndicesService indicesService;
+
+    private final ThreadPool threadPool;
+    private final SegmentReplicationStatsTracker tracker;
+
+    private final ShardStateAction shardStateAction;
+
+    private final AsyncFailStaleReplicaTask failStaleReplicaTask;
+
+    @Inject
+    public SegmentReplicationPressureService(
+        Settings settings,
+        ClusterService clusterService,
+        IndicesService indicesService,
+        ShardStateAction shardStateAction,
+        ThreadPool threadPool
+    ) {
+        this.indicesService = indicesService;
+        this.tracker = new SegmentReplicationStatsTracker(this.indicesService);
+
+        this.shardStateAction = shardStateAction;
+        this.threadPool = threadPool;
+
+        final ClusterSettings clusterSettings = clusterService.getClusterSettings();
+        this.isSegmentReplicationBackpressureEnabled = SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(
+            SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED,
+            this::setSegmentReplicationBackpressureEnabled
+        );
+
+        this.maxCheckpointsBehind = MAX_INDEXING_CHECKPOINTS.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MAX_INDEXING_CHECKPOINTS, this::setMaxCheckpointsBehind);
+
+        this.replicationTimeLimitBackpressure = MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING, this::setReplicationTimeLimitBackpressure);
+
+        this.replicationTimeLimitFailReplica = MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING, this::setReplicationTimeLimitFailReplica);
+
+        this.maxAllowedStaleReplicas = MAX_ALLOWED_STALE_SHARDS.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MAX_ALLOWED_STALE_SHARDS, this::setMaxAllowedStaleReplicas);
+
+        this.failStaleReplicaTask = new AsyncFailStaleReplicaTask(this);
+    }
+
+    // visible for testing
+    AsyncFailStaleReplicaTask getFailStaleReplicaTask() {
+        return failStaleReplicaTask;
+    }
+
+    public void isSegrepLimitBreached(ShardId shardId) {
+        final IndexService indexService = indicesService.indexService(shardId.getIndex());
+        if (indexService != null) {
+            final IndexShard shard = indexService.getShard(shardId.id());
+            if (isSegmentReplicationBackpressureEnabled && shard.indexSettings().isSegRepEnabled() && shard.routingEntry().primary()) {
+                validateReplicationGroup(shard);
+            }
+        }
+    }
+
+    private void validateReplicationGroup(IndexShard shard) {
+        final Set<SegmentReplicationShardStats> replicaStats = shard.getReplicationStatsForTrackedReplicas();
+        final Set<SegmentReplicationShardStats> staleReplicas = getStaleReplicas(replicaStats);
+        if (staleReplicas.isEmpty() == false) {
+            // inSyncIds always considers the primary id, so filter it out.
+            final float percentStale = staleReplicas.size() * 100f / (shard.getReplicationGroup().getInSyncAllocationIds().size() - 1);
+            final double maxStaleLimit = maxAllowedStaleReplicas * 100f;
+            if (percentStale >= maxStaleLimit) {
+                tracker.incrementRejectionCount(shard.shardId());
+                logger.warn("Rejecting write requests for shard, stale shards [{}%] shards: {}", percentStale, staleReplicas);
+                throw new OpenSearchRejectedExecutionException(
+                    "rejected execution on primary shard: " + shard.shardId() + " Stale Replicas: " + staleReplicas + "]",
+                    false
+                );
+            }
+        }
+    }
+
+    private Set<SegmentReplicationShardStats> getStaleReplicas(final Set<SegmentReplicationShardStats> replicas) {
+        return replicas.stream()
+            .filter(entry -> entry.getCheckpointsBehindCount() > maxCheckpointsBehind)
+            .filter(entry -> entry.getCurrentReplicationTimeMillis() > replicationTimeLimitBackpressure.millis())
+            .collect(Collectors.toSet());
+    }
+
+    public SegmentReplicationStats nodeStats() {
+        return tracker.getStats();
+    }
+
+    public SegmentReplicationPerGroupStats getStatsForShard(IndexShard indexShard) {
+        return tracker.getStatsForShard(indexShard);
+    }
+
+    public boolean isSegmentReplicationBackpressureEnabled() {
+        return isSegmentReplicationBackpressureEnabled;
+    }
+
+    public void setSegmentReplicationBackpressureEnabled(boolean segmentReplicationBackpressureEnabled) {
+        isSegmentReplicationBackpressureEnabled = segmentReplicationBackpressureEnabled;
+    }
+
+    public void setMaxCheckpointsBehind(int maxCheckpointsBehind) {
+        this.maxCheckpointsBehind = maxCheckpointsBehind;
+    }
+
+    public void setMaxAllowedStaleReplicas(double maxAllowedStaleReplicas) {
+        this.maxAllowedStaleReplicas = maxAllowedStaleReplicas;
+    }
+
+    public void setReplicationTimeLimitFailReplica(TimeValue replicationTimeLimitFailReplica) {
+        this.replicationTimeLimitFailReplica = replicationTimeLimitFailReplica;
+    }
+
+    public void setReplicationTimeLimitBackpressure(TimeValue replicationTimeLimitBackpressure) {
+        this.replicationTimeLimitBackpressure = replicationTimeLimitBackpressure;
+    }
+
+    @Override
+    public void close() throws IOException {
+        failStaleReplicaTask.close();
+    }
+
+    // Background Task to fail replica shards if they are too far behind primary shard.
+    final static class AsyncFailStaleReplicaTask extends AbstractAsyncTask {
+
+        final SegmentReplicationPressureService pressureService;
+
+        static final TimeValue INTERVAL = TimeValue.timeValueSeconds(30);
+
+        AsyncFailStaleReplicaTask(SegmentReplicationPressureService pressureService) {
+            super(logger, pressureService.threadPool, INTERVAL, true);
+            this.pressureService = pressureService;
+            rescheduleIfNecessary();
+        }
+
+        @Override
+        protected boolean mustReschedule() {
+            return true;
+        }
+
+        @Override
+        protected void runInternal() {
+            // Do not fail the replicas if time limit is set to 0 (i.e. disabled).
+            if (TimeValue.ZERO.equals(pressureService.replicationTimeLimitFailReplica) == false) {
+                final SegmentReplicationStats stats = pressureService.tracker.getStats();
+
+                // Find the shardId in node which is having stale replicas with highest current replication time.
+                // This way we only fail one shardId's stale replicas in every iteration of this background async task and there by decrease
+                // load gradually on node.
+                stats.getShardStats()
+                    .entrySet()
+                    .stream()
+                    .flatMap(
+                        entry -> pressureService.getStaleReplicas(entry.getValue().getReplicaStats())
+                            .stream()
+                            .map(r -> Tuple.tuple(entry.getKey(), r.getCurrentReplicationTimeMillis()))
+                    )
+                    .max(Comparator.comparingLong(Tuple::v2))
+                    .map(Tuple::v1)
+                    .ifPresent(shardId -> {
+                        final Set<SegmentReplicationShardStats> staleReplicas = pressureService.getStaleReplicas(
+                            stats.getShardStats().get(shardId).getReplicaStats()
+                        );
+                        final IndexService indexService = pressureService.indicesService.indexService(shardId.getIndex());
+                        if (indexService.getIndexSettings() != null && indexService.getIndexSettings().isSegRepEnabled() == false) {
+                            return;
+                        }
+                        final IndexShard primaryShard = indexService.getShard(shardId.getId());
+                        for (SegmentReplicationShardStats staleReplica : staleReplicas) {
+                            if (staleReplica.getCurrentReplicationTimeMillis() > pressureService.replicationTimeLimitFailReplica.millis()) {
+                                pressureService.shardStateAction.remoteShardFailed(
+                                    shardId,
+                                    staleReplica.getAllocationId(),
+                                    primaryShard.getOperationPrimaryTerm(),
+                                    true,
+                                    "replica too far behind primary, marking as stale",
+                                    null,
+                                    new ActionListener<>() {
+                                        @Override
+                                        public void onResponse(Void unused) {
+                                            logger.trace(
+                                                "Successfully failed remote shardId [{}] allocation id [{}]",
+                                                shardId,
+                                                staleReplica.getAllocationId()
+                                            );
+                                        }
+
+                                        @Override
+                                        public void onFailure(Exception e) {
+                                            logger.error("Failed to send remote shard failure", e);
+                                        }
+                                    }
+                                );
+                            }
+                        }
+                    });
+            }
+        }
+
+        @Override
+        protected String getThreadPool() {
+            return ThreadPool.Names.GENERIC;
+        }
+
+        @Override
+        public String toString() {
+            return "fail_stale_replica";
+        }
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/SegmentReplicationShardStats.java b/server/src/main/java/org/opensearch/index/SegmentReplicationShardStats.java
new file mode 100644
index 0000000000000..2be0c712f64ef
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/SegmentReplicationShardStats.java
@@ -0,0 +1,156 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.indices.replication.SegmentReplicationState;
+
+import java.io.IOException;
+
+/**
+ * SegRep stats for a single shard.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationShardStats implements Writeable, ToXContentFragment {
+    private final String allocationId;
+    private final long checkpointsBehindCount;
+    private final long bytesBehindCount;
+    // Total Replication lag observed.
+    private final long currentReplicationLagMillis;
+    // Total time taken for replicas to catch up. Similar to replication lag except this
+    // doesn't include time taken by primary to upload data to remote store.
+    private final long currentReplicationTimeMillis;
+    private final long lastCompletedReplicationTimeMillis;
+
+    @Nullable
+    private SegmentReplicationState currentReplicationState;
+
+    public SegmentReplicationShardStats(
+        String allocationId,
+        long checkpointsBehindCount,
+        long bytesBehindCount,
+        long currentReplicationTimeMillis,
+        long currentReplicationLagMillis,
+        long lastCompletedReplicationTime
+    ) {
+        this.allocationId = allocationId;
+        this.checkpointsBehindCount = checkpointsBehindCount;
+        this.bytesBehindCount = bytesBehindCount;
+        this.currentReplicationTimeMillis = currentReplicationTimeMillis;
+        this.currentReplicationLagMillis = currentReplicationLagMillis;
+        this.lastCompletedReplicationTimeMillis = lastCompletedReplicationTime;
+    }
+
+    public SegmentReplicationShardStats(StreamInput in) throws IOException {
+        this.allocationId = in.readString();
+        this.checkpointsBehindCount = in.readVLong();
+        this.bytesBehindCount = in.readVLong();
+        this.currentReplicationTimeMillis = in.readVLong();
+        this.lastCompletedReplicationTimeMillis = in.readVLong();
+        this.currentReplicationLagMillis = in.readVLong();
+    }
+
+    public String getAllocationId() {
+        return allocationId;
+    }
+
+    public long getCheckpointsBehindCount() {
+        return checkpointsBehindCount;
+    }
+
+    public long getBytesBehindCount() {
+        return bytesBehindCount;
+    }
+
+    public long getCurrentReplicationTimeMillis() {
+        return currentReplicationTimeMillis;
+    }
+
+    /**
+     * Total Replication lag observed.
+     * @return currentReplicationLagMillis
+     */
+    public long getCurrentReplicationLagMillis() {
+        return currentReplicationLagMillis;
+    }
+
+    /**
+     * Total time taken for replicas to catch up. Similar to replication lag except this doesn't include time taken by
+     * primary to upload data to remote store.
+     * @return lastCompletedReplicationTimeMillis
+     */
+    public long getLastCompletedReplicationTimeMillis() {
+        return lastCompletedReplicationTimeMillis;
+    }
+
+    public void setCurrentReplicationState(SegmentReplicationState currentReplicationState) {
+        this.currentReplicationState = currentReplicationState;
+    }
+
+    @Nullable
+    public SegmentReplicationState getCurrentReplicationState() {
+        return currentReplicationState;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("allocation_id", allocationId);
+        builder.field("checkpoints_behind", checkpointsBehindCount);
+        builder.field("bytes_behind", new ByteSizeValue(bytesBehindCount).toString());
+        builder.field("current_replication_time", new TimeValue(currentReplicationTimeMillis));
+        builder.field("current_replication_lag", new TimeValue(currentReplicationLagMillis));
+        builder.field("last_completed_replication_time", new TimeValue(lastCompletedReplicationTimeMillis));
+        if (currentReplicationState != null) {
+            builder.startObject();
+            currentReplicationState.toXContent(builder, params);
+            builder.endObject();
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(allocationId);
+        out.writeVLong(checkpointsBehindCount);
+        out.writeVLong(bytesBehindCount);
+        out.writeVLong(currentReplicationTimeMillis);
+        out.writeVLong(lastCompletedReplicationTimeMillis);
+        out.writeVLong(currentReplicationLagMillis);
+    }
+
+    @Override
+    public String toString() {
+        return "SegmentReplicationShardStats{"
+            + "allocationId="
+            + allocationId
+            + ", checkpointsBehindCount="
+            + checkpointsBehindCount
+            + ", bytesBehindCount="
+            + bytesBehindCount
+            + ", currentReplicationLagMillis="
+            + currentReplicationLagMillis
+            + ", currentReplicationTimeMillis="
+            + currentReplicationTimeMillis
+            + ", lastCompletedReplicationTimeMillis="
+            + lastCompletedReplicationTimeMillis
+            + ", currentReplicationState="
+            + currentReplicationState
+            + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/SegmentReplicationStats.java b/server/src/main/java/org/opensearch/index/SegmentReplicationStats.java
new file mode 100644
index 0000000000000..cdf22b05d5861
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/SegmentReplicationStats.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Segment Replication Stats.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStats implements Writeable, ToXContentFragment {
+
+    private final Map<ShardId, SegmentReplicationPerGroupStats> shardStats;
+
+    public SegmentReplicationStats(final Map<ShardId, SegmentReplicationPerGroupStats> shardStats) {
+        this.shardStats = shardStats;
+    }
+
+    public SegmentReplicationStats(StreamInput in) throws IOException {
+        int shardEntries = in.readInt();
+        shardStats = new HashMap<>();
+        for (int i = 0; i < shardEntries; i++) {
+            ShardId shardId = new ShardId(in);
+            SegmentReplicationPerGroupStats groupStats = new SegmentReplicationPerGroupStats(in);
+            shardStats.put(shardId, groupStats);
+        }
+    }
+
+    public Map<ShardId, SegmentReplicationPerGroupStats> getShardStats() {
+        return shardStats;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject("segment_replication");
+        for (Map.Entry<ShardId, SegmentReplicationPerGroupStats> entry : shardStats.entrySet()) {
+            builder.startObject(entry.getKey().toString());
+            entry.getValue().toXContent(builder, params);
+            builder.endObject();
+        }
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeInt(shardStats.size());
+        for (Map.Entry<ShardId, SegmentReplicationPerGroupStats> entry : shardStats.entrySet()) {
+            entry.getKey().writeTo(out);
+            entry.getValue().writeTo(out);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "SegmentReplicationStats{" + "shardStats=" + shardStats + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/SegmentReplicationStatsTracker.java b/server/src/main/java/org/opensearch/index/SegmentReplicationStatsTracker.java
new file mode 100644
index 0000000000000..6d5c00c08caff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/SegmentReplicationStatsTracker.java
@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Tracker responsible for computing SegmentReplicationStats.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationStatsTracker {
+
+    private final IndicesService indicesService;
+    private final Map<ShardId, AtomicInteger> rejectionCount;
+
+    public SegmentReplicationStatsTracker(IndicesService indicesService) {
+        this.indicesService = indicesService;
+        rejectionCount = ConcurrentCollections.newConcurrentMap();
+    }
+
+    public SegmentReplicationStats getStats() {
+        Map<ShardId, SegmentReplicationPerGroupStats> stats = new HashMap<>();
+        for (IndexService indexService : indicesService) {
+            for (IndexShard indexShard : indexService) {
+                if (indexShard.indexSettings().isSegRepEnabled() && indexShard.routingEntry().primary()) {
+                    stats.putIfAbsent(indexShard.shardId(), getStatsForShard(indexShard));
+                }
+            }
+        }
+        return new SegmentReplicationStats(stats);
+    }
+
+    public void incrementRejectionCount(ShardId shardId) {
+        rejectionCount.compute(shardId, (k, v) -> {
+            if (v == null) {
+                return new AtomicInteger(1);
+            } else {
+                v.incrementAndGet();
+                return v;
+            }
+        });
+    }
+
+    public SegmentReplicationPerGroupStats getStatsForShard(IndexShard indexShard) {
+        return new SegmentReplicationPerGroupStats(
+            indexShard.shardId(),
+            indexShard.getReplicationStatsForTrackedReplicas(),
+            Optional.ofNullable(rejectionCount.get(indexShard.shardId())).map(AtomicInteger::get).orElse(0)
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/ShardIndexingPressure.java b/server/src/main/java/org/opensearch/index/ShardIndexingPressure.java
index 881ede2f6903f..07768c6769b71 100644
--- a/server/src/main/java/org/opensearch/index/ShardIndexingPressure.java
+++ b/server/src/main/java/org/opensearch/index/ShardIndexingPressure.java
@@ -12,15 +12,15 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.ShardIndexingPressureTracker.CommonOperationTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.OperationTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.PerformanceTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.RejectionTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.StatsTracker;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.stats.ShardIndexingPressureStats;
 import org.opensearch.index.stats.IndexingPressurePerShardStats;
+import org.opensearch.index.stats.ShardIndexingPressureStats;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -39,6 +39,8 @@
  * 1. Memory Accounting at shard level. This can be enabled/disabled based on dynamic setting.
  * 2. Memory Accounting at Node level. Tracking is done using the IndexingPressure artefacts to support feature seamless toggling.
  * 3. Interfaces to access the statistics for shard trackers.
+ *
+ * @opensearch.internal
  */
 public class ShardIndexingPressure extends IndexingPressure {
 
diff --git a/server/src/main/java/org/opensearch/index/ShardIndexingPressureMemoryManager.java b/server/src/main/java/org/opensearch/index/ShardIndexingPressureMemoryManager.java
index fff0649a4327f..dea3cc8970cb5 100644
--- a/server/src/main/java/org/opensearch/index/ShardIndexingPressureMemoryManager.java
+++ b/server/src/main/java/org/opensearch/index/ShardIndexingPressureMemoryManager.java
@@ -14,11 +14,11 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.ShardIndexingPressureTracker.OperationTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.PerformanceTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.RejectionTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.StatsTracker;
-import org.opensearch.index.shard.ShardId;
 
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
@@ -52,6 +52,7 @@
  * goes above operating_factor.upper of current shard limits. MemoryManager attempts to update the new shard limit such that the new value
  * remains withing the operating_factor.optimal range of current shard utilization.
  *
+ * @opensearch.internal
  */
 public class ShardIndexingPressureMemoryManager {
     private static final Logger logger = LogManager.getLogger(ShardIndexingPressureMemoryManager.class);
diff --git a/server/src/main/java/org/opensearch/index/ShardIndexingPressureSettings.java b/server/src/main/java/org/opensearch/index/ShardIndexingPressureSettings.java
index b1fa1f0bd3b65..35e93162788b5 100644
--- a/server/src/main/java/org/opensearch/index/ShardIndexingPressureSettings.java
+++ b/server/src/main/java/org/opensearch/index/ShardIndexingPressureSettings.java
@@ -14,6 +14,8 @@
  * This class contains all the settings which are required and owned by {TODO link ShardIndexingPressure}. These will be
  * referenced/used in ShardIndexingPressure, as well as its dependent components, i.e.
  * {TODO link ShardIndexingPressureMemoryManager} and {TODO link ShardIndexingPressureStore}
+ *
+ * @opensearch.internal
  */
 public final class ShardIndexingPressureSettings {
 
diff --git a/server/src/main/java/org/opensearch/index/ShardIndexingPressureStore.java b/server/src/main/java/org/opensearch/index/ShardIndexingPressureStore.java
index bcc883a569f25..b41dd1359394b 100644
--- a/server/src/main/java/org/opensearch/index/ShardIndexingPressureStore.java
+++ b/server/src/main/java/org/opensearch/index/ShardIndexingPressureStore.java
@@ -9,7 +9,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -44,6 +44,7 @@
  * update and evict operations can be abstracted out to support any other strategy such as LRU, if
  * discovered a need later.
  *
+ * @opensearch.internal
  */
 public class ShardIndexingPressureStore {
 
diff --git a/server/src/main/java/org/opensearch/index/ShardIndexingPressureTracker.java b/server/src/main/java/org/opensearch/index/ShardIndexingPressureTracker.java
index e63425eef825c..7d67b47141ef5 100644
--- a/server/src/main/java/org/opensearch/index/ShardIndexingPressureTracker.java
+++ b/server/src/main/java/org/opensearch/index/ShardIndexingPressureTracker.java
@@ -5,7 +5,7 @@
 
 package org.opensearch.index;
 
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.atomic.AtomicLong;
@@ -31,6 +31,8 @@
  * increase the complexity of handling shard-lister events and handling other race scenarios such as request-draining etc.
  * To prefer simplicity we have modelled by keeping explicit fields for different operation tracking, while tracker by itself is
  * agnostic of the actual shard role.
+ *
+ * @opensearch.internal
  */
 public class ShardIndexingPressureTracker {
 
@@ -90,6 +92,8 @@ public CommonOperationTracker getCommonOperationTracker() {
      * a. StatsTracker : To track request level aggregated statistics for a shard
      * b. RejectionTracker : To track the rejection statistics for a shard
      * c. Performance Tracker : To track the request performance statistics for a shard
+     *
+     * @opensearch.internal
      */
     public static class OperationTracker {
         private final StatsTracker statsTracker = new StatsTracker();
@@ -114,6 +118,8 @@ public PerformanceTracker getPerformanceTracker() {
      * a. currentBytes - Bytes of data that is inflight/processing for a shard.
      * b. totalBytes - Total bytes that are processed/completed successfully for a shard.
      * c. requestCount - Total number of requests that are processed/completed successfully for a shard.
+     *
+     * @opensearch.internal
      */
     public static class StatsTracker {
         private final AtomicLong currentBytes = new AtomicLong();
@@ -154,6 +160,8 @@ public long incrementRequestCount() {
      *          last successful request limits breached for a shard i.e. complete path failure (black-hole).
      * d. throughputDegradationLimitsBreachedRejections - Total number of requests that were rejected due to the
      *          throughput degradation in the request path for a shard i.e. partial failure.
+     *
+     * @opensearch.internal
      */
     public static class RejectionTracker {
         private final AtomicLong totalRejections = new AtomicLong();
@@ -203,6 +211,8 @@ public long incrementThroughputDegradationLimitsBreachedRejections() {
      * e. ThroughputMovingQueue - Queue that holds the last N requests throughput such that there exists a sliding window
      *          which keeps moving everytime a new request comes. At any given point it tracks last N requests only.
      *          EWMA cannot be used here as it evaluate the historical average, while here it just needs the average of last N requests.
+     *
+     * @opensearch.internal
      */
     public static class PerformanceTracker {
         private final AtomicLong latencyInMillis = new AtomicLong();
@@ -271,6 +281,8 @@ public long getThroughputMovingQueueSize() {
      *      when primary is local to coordinator node. Hence common accounting for coordinator and primary operation.
      * b. totalCombinedCoordinatingAndPrimaryBytes - Total bytes that are processed/completed successfully for a shard
      *      when primary is local to coordinator node. Hence common accounting for coordinator and primary operation.
+     *
+     * @opensearch.internal
      */
     public static class CommonOperationTracker {
         private final AtomicLong currentCombinedCoordinatingAndPrimaryBytes = new AtomicLong();
diff --git a/server/src/main/java/org/opensearch/index/SlowLogLevel.java b/server/src/main/java/org/opensearch/index/SlowLogLevel.java
index ca628aba14d18..0a28edd59d491 100644
--- a/server/src/main/java/org/opensearch/index/SlowLogLevel.java
+++ b/server/src/main/java/org/opensearch/index/SlowLogLevel.java
@@ -33,6 +33,11 @@
 
 import java.util.Locale;
 
+/**
+ * Levels for the slow logs
+ *
+ * @opensearch.internal
+ */
 public enum SlowLogLevel {
     WARN(3), // most specific - little logging
     INFO(2),
diff --git a/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java b/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java
new file mode 100644
index 0000000000000..d5d354c6c960a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/TieredMergePolicyProvider.java
@@ -0,0 +1,323 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.index;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.index.LogByteSizeMergePolicy;
+import org.apache.lucene.index.MergePolicy;
+import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.TieredMergePolicy;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+
+/**
+ * A shard in opensearch is a Lucene index, and a Lucene index is broken
+ * down into segments. Segments are internal storage elements in the index
+ * where the index data is stored, and are immutable up to delete markers.
+ * Segments are, periodically, merged into larger segments to keep the
+ * index size at bay and expunge deletes.
+ * This class customizes and exposes 2 merge policies from lucene -
+ * {@link LogByteSizeMergePolicy} and  {@link TieredMergePolicy}.
+ *
+ *
+ * <p>
+ * Tiered merge policy select segments of approximately equal size, subject to an allowed
+ * number of segments per tier. The merge policy is able to merge
+ * non-adjacent segments, and separates how many segments are merged at once from how many
+ * segments are allowed per tier. It also does not over-merge (i.e., cascade merges).
+ *
+ * <p>
+ * All merge policy settings are <b>dynamic</b> and can be updated on a live index.
+ * The merge policy has the following settings:
+ *
+ * <ul>
+ * <li><code>index.merge.policy.expunge_deletes_allowed</code>:
+ *
+ *     When expungeDeletes is called, we only merge away a segment if its delete
+ *     percentage is over this threshold. Default is <code>10</code>.
+ *
+ * <li><code>index.merge.policy.floor_segment</code>:
+ *
+ *     Segments smaller than this are "rounded up" to this size, i.e. treated as
+ *     equal (floor) size for merge selection. This is to prevent frequent
+ *     flushing of tiny segments, thus preventing a long tail in the index. Default
+ *     is <code>2mb</code>.
+ *
+ * <li><code>index.merge.policy.max_merge_at_once</code>:
+ *
+ *     Maximum number of segments to be merged at a time during "normal" merging.
+ *     Default is <code>10</code>.
+ *
+ * <li><code>index.merge.policy.max_merged_segment</code>:
+ *
+ *     Maximum sized segment to produce during normal merging (not explicit
+ *     force merge). This setting is approximate: the estimate of the merged
+ *     segment size is made by summing sizes of to-be-merged segments
+ *     (compensating for percent deleted docs). Default is <code>5gb</code>.
+ *
+ * <li><code>index.merge.policy.segments_per_tier</code>:
+ *
+ *     Sets the allowed number of segments per tier. Smaller values mean more
+ *     merging but fewer segments. Default is <code>10</code>. Note, this value needs to be
+ *     &gt;= than the <code>max_merge_at_once</code> otherwise you'll force too many merges to
+ *     occur.
+ *
+ * <li><code>index.merge.policy.deletes_pct_allowed</code>:
+ *
+ *     Controls the maximum percentage of deleted documents that is tolerated in
+ *     the index. Lower values make the index more space efficient at the
+ *     expense of increased CPU and I/O activity. Values must be between <code>5</code> and
+ *     <code>50</code>. Default value is <code>20</code>.
+ * </ul>
+ *
+ * <p>
+ * For normal merging, the policy first computes a "budget" of how many
+ * segments are allowed to be in the index. If the index is over-budget,
+ * then the policy sorts segments by decreasing size (proportionally considering percent
+ * deletes), and then finds the least-cost merge. Merge cost is measured by
+ * a combination of the "skew" of the merge (size of largest seg divided by
+ * smallest seg), total merge size and pct deletes reclaimed, so that
+ * merges with lower skew, smaller size and those reclaiming more deletes,
+ * are favored.
+ *
+ * <p>
+ * If a merge will produce a segment that's larger than
+ * <code>max_merged_segment</code> then the policy will merge fewer segments (down to
+ * 1 at once, if that one has deletions) to keep the segment size under
+ * budget.
+ *
+ * <p>
+ * Note, this can mean that for large shards that holds many gigabytes of
+ * data, the default of <code>max_merged_segment</code> (<code>5gb</code>) can cause for many
+ * segments to be in an index, and causing searches to be slower. Use the
+ * indices segments API to see the segments that an index has, and
+ * possibly either increase the <code>max_merged_segment</code> or issue an optimize
+ * call for the index (try and aim to issue it on a low traffic time).
+ *
+ * @opensearch.internal
+ */
+
+public final class TieredMergePolicyProvider implements MergePolicyProvider {
+    private final OpenSearchTieredMergePolicy tieredMergePolicy = new OpenSearchTieredMergePolicy();
+
+    private final Logger logger;
+    private final boolean mergesEnabled;
+
+    public static final double DEFAULT_EXPUNGE_DELETES_ALLOWED = 10d;
+    public static final ByteSizeValue DEFAULT_FLOOR_SEGMENT = new ByteSizeValue(2, ByteSizeUnit.MB);
+    public static final int DEFAULT_MAX_MERGE_AT_ONCE = 10;
+    public static final ByteSizeValue DEFAULT_MAX_MERGED_SEGMENT = new ByteSizeValue(5, ByteSizeUnit.GB);
+    public static final double DEFAULT_SEGMENTS_PER_TIER = 10.0d;
+    public static final double DEFAULT_RECLAIM_DELETES_WEIGHT = 2.0d;
+    public static final double DEFAULT_DELETES_PCT_ALLOWED = 20.0d;
+
+    public static final Setting<Double> INDEX_COMPOUND_FORMAT_SETTING = new Setting<>(
+        "index.compound_format",
+        Double.toString(TieredMergePolicy.DEFAULT_NO_CFS_RATIO),
+        TieredMergePolicyProvider::parseNoCFSRatio,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
+    public static final Setting<Double> INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING = Setting.doubleSetting(
+        "index.merge.policy.expunge_deletes_allowed",
+        DEFAULT_EXPUNGE_DELETES_ALLOWED,
+        0.0d,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+    public static final Setting<ByteSizeValue> INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING = Setting.byteSizeSetting(
+        "index.merge.policy.floor_segment",
+        DEFAULT_FLOOR_SEGMENT,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+    public static final Setting<Integer> INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING = Setting.intSetting(
+        "index.merge.policy.max_merge_at_once",
+        DEFAULT_MAX_MERGE_AT_ONCE,
+        2,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+    public static final Setting<ByteSizeValue> INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING = Setting.byteSizeSetting(
+        "index.merge.policy.max_merged_segment",
+        DEFAULT_MAX_MERGED_SEGMENT,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+    public static final Setting<Double> INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING = Setting.doubleSetting(
+        "index.merge.policy.segments_per_tier",
+        DEFAULT_SEGMENTS_PER_TIER,
+        2.0d,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+    public static final Setting<Double> INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING = Setting.doubleSetting(
+        "index.merge.policy.reclaim_deletes_weight",
+        DEFAULT_RECLAIM_DELETES_WEIGHT,
+        0.0d,
+        Property.Dynamic,
+        Property.IndexScope,
+        Property.Deprecated
+    );
+    public static final Setting<Double> INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING = Setting.doubleSetting(
+        "index.merge.policy.deletes_pct_allowed",
+        DEFAULT_DELETES_PCT_ALLOWED,
+        5.0d,
+        50.0d,
+        Property.Dynamic,
+        Property.IndexScope
+    );
+
+    TieredMergePolicyProvider(Logger logger, IndexSettings indexSettings) {
+        this.logger = logger;
+        double forceMergeDeletesPctAllowed = indexSettings.getValue(INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING); // percentage
+        ByteSizeValue floorSegment = indexSettings.getValue(INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING);
+        int maxMergeAtOnce = indexSettings.getValue(INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING);
+        // TODO is this really a good default number for max_merge_segment, what happens for large indices,
+        // won't they end up with many segments?
+        ByteSizeValue maxMergedSegment = indexSettings.getValue(INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING);
+        double segmentsPerTier = indexSettings.getValue(INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING);
+        double reclaimDeletesWeight = indexSettings.getValue(INDEX_MERGE_POLICY_RECLAIM_DELETES_WEIGHT_SETTING);
+        double deletesPctAllowed = indexSettings.getValue(INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING);
+        this.mergesEnabled = indexSettings.getSettings().getAsBoolean(INDEX_MERGE_ENABLED, true);
+        if (mergesEnabled == false) {
+            logger.warn(
+                "[{}] is set to false, this should only be used in tests and can cause serious problems in production" + " environments",
+                INDEX_MERGE_ENABLED
+            );
+        }
+        maxMergeAtOnce = adjustMaxMergeAtOnceIfNeeded(maxMergeAtOnce, segmentsPerTier);
+        tieredMergePolicy.setNoCFSRatio(indexSettings.getValue(INDEX_COMPOUND_FORMAT_SETTING));
+        tieredMergePolicy.setForceMergeDeletesPctAllowed(forceMergeDeletesPctAllowed);
+        tieredMergePolicy.setFloorSegmentMB(floorSegment.getMbFrac());
+        tieredMergePolicy.setMaxMergeAtOnce(maxMergeAtOnce);
+        tieredMergePolicy.setMaxMergedSegmentMB(maxMergedSegment.getMbFrac());
+        tieredMergePolicy.setSegmentsPerTier(segmentsPerTier);
+        tieredMergePolicy.setDeletesPctAllowed(deletesPctAllowed);
+    }
+
+    void setSegmentsPerTier(Double segmentsPerTier) {
+        tieredMergePolicy.setSegmentsPerTier(segmentsPerTier);
+    }
+
+    void setMaxMergedSegment(ByteSizeValue maxMergedSegment) {
+        tieredMergePolicy.setMaxMergedSegmentMB(maxMergedSegment.getMbFrac());
+    }
+
+    void setMaxMergesAtOnce(Integer maxMergeAtOnce) {
+        tieredMergePolicy.setMaxMergeAtOnce(maxMergeAtOnce);
+    }
+
+    void setFloorSegmentSetting(ByteSizeValue floorSegementSetting) {
+        tieredMergePolicy.setFloorSegmentMB(floorSegementSetting.getMbFrac());
+    }
+
+    void setExpungeDeletesAllowed(Double value) {
+        tieredMergePolicy.setForceMergeDeletesPctAllowed(value);
+    }
+
+    void setNoCFSRatio(Double noCFSRatio) {
+        tieredMergePolicy.setNoCFSRatio(noCFSRatio);
+    }
+
+    void setDeletesPctAllowed(Double deletesPctAllowed) {
+        tieredMergePolicy.setDeletesPctAllowed(deletesPctAllowed);
+    }
+
+    private int adjustMaxMergeAtOnceIfNeeded(int maxMergeAtOnce, double segmentsPerTier) {
+        // fixing maxMergeAtOnce, see TieredMergePolicy#setMaxMergeAtOnce
+        if (!(segmentsPerTier >= maxMergeAtOnce)) {
+            int newMaxMergeAtOnce = (int) segmentsPerTier;
+            // max merge at once should be at least 2
+            if (newMaxMergeAtOnce <= 1) {
+                newMaxMergeAtOnce = 2;
+            }
+            logger.debug(
+                "changing max_merge_at_once from [{}] to [{}] because segments_per_tier [{}] has to be higher or " + "equal to it",
+                maxMergeAtOnce,
+                newMaxMergeAtOnce,
+                segmentsPerTier
+            );
+            maxMergeAtOnce = newMaxMergeAtOnce;
+        }
+        return maxMergeAtOnce;
+    }
+
+    public MergePolicy getMergePolicy() {
+        return mergesEnabled ? tieredMergePolicy : NoMergePolicy.INSTANCE;
+    }
+
+    public static double parseNoCFSRatio(String noCFSRatio) {
+        noCFSRatio = noCFSRatio.trim();
+        if (noCFSRatio.equalsIgnoreCase("true")) {
+            return 1.0d;
+        } else if (noCFSRatio.equalsIgnoreCase("false")) {
+            return 0.0;
+        } else {
+            try {
+                double value = Double.parseDouble(noCFSRatio);
+                if (value < 0.0 || value > 1.0) {
+                    throw new IllegalArgumentException("NoCFSRatio must be in the interval [0..1] but was: [" + value + "]");
+                }
+                return value;
+            } catch (NumberFormatException ex) {
+                throw new IllegalArgumentException(
+                    "Expected a boolean or a value in the interval [0..1] but was: " + "[" + noCFSRatio + "]",
+                    ex
+                );
+            }
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "TieredMergePolicyProvider{"
+            + "expungeDeletesAllowed="
+            + tieredMergePolicy.getForceMergeDeletesPctAllowed()
+            + ", floorSegment="
+            + tieredMergePolicy.getFloorSegmentMB()
+            + ", maxMergeAtOnce="
+            + tieredMergePolicy.getMaxMergeAtOnce()
+            + ", maxMergedSegment="
+            + tieredMergePolicy.getMaxMergedSegmentMB()
+            + ", segmentsPerTier="
+            + tieredMergePolicy.getSegmentsPerTier()
+            + ", deletesPctAllowed="
+            + tieredMergePolicy.getDeletesPctAllowed()
+            + '}';
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/VersionType.java b/server/src/main/java/org/opensearch/index/VersionType.java
index 54ad2c7292eb7..3ce7f600a6a5b 100644
--- a/server/src/main/java/org/opensearch/index/VersionType.java
+++ b/server/src/main/java/org/opensearch/index/VersionType.java
@@ -31,14 +31,19 @@
 
 package org.opensearch.index;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 
+/**
+ * Types of index versions
+ *
+ * @opensearch.internal
+ */
 public enum VersionType implements Writeable {
     INTERNAL((byte) 0) {
         @Override
diff --git a/server/src/main/java/org/opensearch/index/analysis/AbstractCharFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/AbstractCharFilterFactory.java
index d632b3db3dcb4..dcc03252e4901 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AbstractCharFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AbstractCharFilterFactory.java
@@ -35,6 +35,11 @@
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base character filter factory used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractCharFilterFactory extends AbstractIndexComponent implements CharFilterFactory {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/index/analysis/AbstractIndexAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/AbstractIndexAnalyzerProvider.java
index e1c5fd0ba3c64..b21c972944d4f 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AbstractIndexAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AbstractIndexAnalyzerProvider.java
@@ -37,6 +37,11 @@
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base analyzer component
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractIndexAnalyzerProvider<T extends Analyzer> extends AbstractIndexComponent implements AnalyzerProvider<T> {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/index/analysis/AbstractTokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/AbstractTokenFilterFactory.java
index fb465eb273382..e5ccd9a0c3f1a 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AbstractTokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AbstractTokenFilterFactory.java
@@ -36,6 +36,11 @@
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base tokenfilter factory used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractTokenFilterFactory extends AbstractIndexComponent implements TokenFilterFactory {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/index/analysis/AbstractTokenizerFactory.java b/server/src/main/java/org/opensearch/index/analysis/AbstractTokenizerFactory.java
index 9a0f4196bab16..fce420a5e424d 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AbstractTokenizerFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AbstractTokenizerFactory.java
@@ -36,6 +36,11 @@
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base tokenizer factory used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractTokenizerFactory extends AbstractIndexComponent implements TokenizerFactory {
     private final String name;
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/Analysis.java b/server/src/main/java/org/opensearch/index/analysis/Analysis.java
index 90bb21cfc0a4b..6294230a02ada 100644
--- a/server/src/main/java/org/opensearch/index/analysis/Analysis.java
+++ b/server/src/main/java/org/opensearch/index/analysis/Analysis.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.index.analysis;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.CharArraySet;
 import org.apache.lucene.analysis.ar.ArabicAnalyzer;
 import org.apache.lucene.analysis.bg.BulgarianAnalyzer;
@@ -67,8 +69,8 @@
 import org.apache.lucene.analysis.sv.SwedishAnalyzer;
 import org.apache.lucene.analysis.th.ThaiAnalyzer;
 import org.apache.lucene.analysis.tr.TurkishAnalyzer;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.env.Environment;
 
 import java.io.BufferedReader;
@@ -85,10 +87,20 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.regex.Pattern;
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Core analysis class
+ *
+ * @opensearch.internal
+ */
 public class Analysis {
+    private static final Logger LOGGER = LogManager.getLogger(Analysis.class);
+
+    // Regular expression to support hashtag tokenization
+    private static final Pattern HASH_TAG_RULE_PATTERN = Pattern.compile("^\\s*#\\s*=>");
 
     public static CharArraySet parseStemExclusion(Settings settings, CharArraySet defaultStemExclusion) {
         String value = settings.get("stem_exclusion");
@@ -161,7 +173,7 @@ public static CharArraySet parseWords(
                 return resolveNamedWords(settings.getAsList(name), namedWords, ignoreCase);
             }
         }
-        List<String> pathLoadedWords = getWordList(env, settings, name);
+        List<String> pathLoadedWords = parseWordList(env, settings, name, s -> s);
         if (pathLoadedWords != null) {
             return resolveNamedWords(pathLoadedWords, namedWords, ignoreCase);
         }
@@ -202,7 +214,7 @@ private static CharArraySet resolveNamedWords(Collection<String> words, Map<Stri
     }
 
     public static CharArraySet getWordSet(Environment env, Settings settings, String settingsPrefix) {
-        List<String> wordList = getWordList(env, settings, settingsPrefix);
+        List<String> wordList = parseWordList(env, settings, settingsPrefix, s -> s);
         if (wordList == null) {
             return null;
         }
@@ -210,15 +222,48 @@ public static CharArraySet getWordSet(Environment env, Settings settings, String
         return new CharArraySet(wordList, ignoreCase);
     }
 
+    public static <T> List<T> parseWordList(Environment env, Settings settings, String settingPrefix, CustomMappingRuleParser<T> parser) {
+        return parseWordList(env, settings, settingPrefix + "_path", settingPrefix, parser);
+    }
+
     /**
-     * Fetches a list of words from the specified settings file. The list should either be available at the key
-     * specified by settingsPrefix or in a file specified by settingsPrefix + _path.
+     * Parses a list of words from the specified settings or from a file, with the given parser.
      *
      * @throws IllegalArgumentException
      *          If the word list cannot be found at either key.
+     * @throws RuntimeException
+     *          If there is error parsing the words
      */
-    public static List<String> getWordList(Environment env, Settings settings, String settingPrefix) {
-        return getWordList(env, settings, settingPrefix + "_path", settingPrefix, true);
+    public static <T> List<T> parseWordList(
+        Environment env,
+        Settings settings,
+        String settingPath,
+        String settingList,
+        CustomMappingRuleParser<T> parser
+    ) {
+        List<String> words = getWordList(env, settings, settingPath, settingList);
+        if (words == null) {
+            return null;
+        }
+        List<T> rules = new ArrayList<>();
+        int lineNum = 0;
+        for (String word : words) {
+            lineNum++;
+            if (word.startsWith("#") == false || HASH_TAG_RULE_PATTERN.matcher(word).find() == true) {
+                try {
+                    rules.add(parser.apply(word));
+                } catch (RuntimeException ex) {
+                    String wordListPath = settings.get(settingPath, null);
+                    if (wordListPath == null || isUnderConfig(env, wordListPath)) {
+                        throw new RuntimeException("Line [" + lineNum + "]: " + ex.getMessage());
+                    } else {
+                        LOGGER.error("Line [{}]: {}", lineNum, ex);
+                        throw new RuntimeException("Line [" + lineNum + "]: " + "Invalid rule");
+                    }
+                }
+            }
+        }
+        return rules;
     }
 
     /**
@@ -228,43 +273,33 @@ public static List<String> getWordList(Environment env, Settings settings, Strin
      * @throws IllegalArgumentException
      *          If the word list cannot be found at either key.
      */
-    public static List<String> getWordList(
-        Environment env,
-        Settings settings,
-        String settingPath,
-        String settingList,
-        boolean removeComments
-    ) {
+    private static List<String> getWordList(Environment env, Settings settings, String settingPath, String settingList) {
         String wordListPath = settings.get(settingPath, null);
 
         if (wordListPath == null) {
-            List<String> explicitWordList = settings.getAsList(settingList, null);
-            if (explicitWordList == null) {
-                return null;
-            } else {
-                return explicitWordList;
-            }
+            return settings.getAsList(settingList, null);
         }
 
-        final Path path = env.configFile().resolve(wordListPath);
+        final Path path = resolveAnalyzerPath(env, wordListPath);
 
         try {
-            return loadWordList(path, removeComments);
+            return loadWordList(path);
         } catch (CharacterCodingException ex) {
             String message = String.format(
                 Locale.ROOT,
-                "Unsupported character encoding detected while reading %s: %s - files must be UTF-8 encoded",
-                settingPath,
-                path.toString()
+                "Unsupported character encoding detected while reading %s: files must be UTF-8 encoded",
+                settingPath
             );
-            throw new IllegalArgumentException(message, ex);
+            LOGGER.error("{}: from file: {}, exception is: {}", message, path.toString(), ex);
+            throw new IllegalArgumentException(message);
         } catch (IOException ioe) {
-            String message = String.format(Locale.ROOT, "IOException while reading %s: %s", settingPath, path.toString());
-            throw new IllegalArgumentException(message, ioe);
+            String message = String.format(Locale.ROOT, "IOException while reading %s: file not readable", settingPath);
+            LOGGER.error("{}, from file: {}, exception is: {}", message, path.toString(), ioe);
+            throw new IllegalArgumentException(message);
         }
     }
 
-    private static List<String> loadWordList(Path path, boolean removeComments) throws IOException {
+    private static List<String> loadWordList(Path path) throws IOException {
         final List<String> result = new ArrayList<>();
         try (BufferedReader br = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
             String word;
@@ -272,9 +307,7 @@ private static List<String> loadWordList(Path path, boolean removeComments) thro
                 if (Strings.hasText(word) == false) {
                     continue;
                 }
-                if (removeComments == false || word.startsWith("#") == false) {
-                    result.add(word.trim());
-                }
+                result.add(word.trim());
             }
         }
         return result;
@@ -291,21 +324,34 @@ public static Reader getReaderFromFile(Environment env, Settings settings, Strin
         if (filePath == null) {
             return null;
         }
-        final Path path = env.configFile().resolve(filePath);
+        final Path path = resolveAnalyzerPath(env, filePath);
         try {
             return Files.newBufferedReader(path, StandardCharsets.UTF_8);
         } catch (CharacterCodingException ex) {
             String message = String.format(
                 Locale.ROOT,
-                "Unsupported character encoding detected while reading %s_path: %s files must be UTF-8 encoded",
-                settingPrefix,
-                path.toString()
+                "Unsupported character encoding detected while reading %s_path: files must be UTF-8 encoded",
+                settingPrefix
             );
-            throw new IllegalArgumentException(message, ex);
+            LOGGER.error("{}: from file: {}, exception is: {}", message, path.toString(), ex);
+            throw new IllegalArgumentException(message);
         } catch (IOException ioe) {
-            String message = String.format(Locale.ROOT, "IOException while reading %s_path: %s", settingPrefix, path.toString());
-            throw new IllegalArgumentException(message, ioe);
+            String message = String.format(Locale.ROOT, "IOException while reading %s_path: file not readable", settingPrefix);
+            LOGGER.error("{}, from file: {}, exception is: {}", message, path.toString(), ioe);
+            throw new IllegalArgumentException(message);
         }
     }
 
+    public static Path resolveAnalyzerPath(Environment env, String wordListPath) {
+        return env.configFile().resolve(wordListPath).normalize();
+    }
+
+    private static boolean isUnderConfig(Environment env, String wordListPath) {
+        try {
+            final Path path = env.configFile().resolve(wordListPath).normalize();
+            return path.startsWith(env.configFile().toAbsolutePath());
+        } catch (Exception ex) {
+            return false;
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalysisMode.java b/server/src/main/java/org/opensearch/index/analysis/AnalysisMode.java
index a94820499040e..4385680d9eb93 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalysisMode.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalysisMode.java
@@ -36,6 +36,8 @@
  * Enum representing the mode in which token filters and analyzers are allowed to operate.
  * While most token filters are allowed both in index and search time analyzers, some are
  * restricted to be used only at index time, others at search time.
+ *
+ * @opensearch.internal
  */
 public enum AnalysisMode {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalysisRegistry.java b/server/src/main/java/org/opensearch/index/analysis/AnalysisRegistry.java
index dc0e7b13eeb7e..4f11eacb3178a 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalysisRegistry.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalysisRegistry.java
@@ -40,7 +40,7 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.TextFieldMapper;
@@ -67,6 +67,8 @@
 /**
  * An internal registry for tokenizer, token filter, char filter and analyzer.
  * This class exists per node and allows to create per-index {@link IndexAnalyzers} via {@link #build(IndexSettings)}
+ *
+ * @opensearch.internal
  */
 public final class AnalysisRegistry implements Closeable {
     public static final String INDEX_ANALYSIS_CHAR_FILTER = "index.analysis.char_filter";
@@ -568,6 +570,11 @@ private static <T> AnalysisProvider<T> getAnalysisProvider(
         return type;
     }
 
+    /**
+     * Internal prebuilt analysis class
+     *
+     * @opensearch.internal
+     */
     private static class PrebuiltAnalysis implements Closeable {
 
         final Map<String, AnalysisProvider<AnalyzerProvider<?>>> analyzerProviderFactories;
@@ -641,7 +648,9 @@ public IndexAnalyzers build(
                     charFilterFactoryFactories,
                     tokenizerFactoryFactories
                 ),
-                (k, v) -> { throw new IllegalStateException("already registered analyzer with name: " + entry.getKey()); }
+                (k, v) -> {
+                    throw new IllegalStateException("already registered analyzer with name: " + entry.getKey());
+                }
             );
         }
         for (Map.Entry<String, AnalyzerProvider<?>> entry : normalizerProviders.entrySet()) {
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponents.java b/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponents.java
index 9fd36fdee4c6c..97e31c480572a 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponents.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponents.java
@@ -41,6 +41,8 @@
 /**
  * A class that groups analysis components necessary to produce a custom analyzer.
  * See {@link ReloadableCustomAnalyzer} for an example usage.
+ *
+ * @opensearch.internal
  */
 public final class AnalyzerComponents {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponentsProvider.java b/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponentsProvider.java
index 305fc84178c19..0fe720a01e5a6 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponentsProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalyzerComponentsProvider.java
@@ -34,6 +34,8 @@
 
 /**
  * Analyzers that provide access to their token filters should implement this
+ *
+ * @opensearch.internal
  */
 public interface AnalyzerComponentsProvider {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/AnalyzerProvider.java
index e4a0c8b73b7f1..24ddabca16f1e 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalyzerProvider.java
@@ -35,6 +35,11 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.opensearch.common.inject.Provider;
 
+/**
+ * Base interface for all analyzer providers
+ *
+ * @opensearch.internal
+ */
 public interface AnalyzerProvider<T extends Analyzer> extends Provider<T> {
 
     String name();
diff --git a/server/src/main/java/org/opensearch/index/analysis/AnalyzerScope.java b/server/src/main/java/org/opensearch/index/analysis/AnalyzerScope.java
index c61c1283c160f..0ee51b32aab46 100644
--- a/server/src/main/java/org/opensearch/index/analysis/AnalyzerScope.java
+++ b/server/src/main/java/org/opensearch/index/analysis/AnalyzerScope.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.index.analysis;
 
+/**
+ * Enum to identify the scope of an analyzer
+ *
+ * @opensearch.internal
+ */
 public enum AnalyzerScope {
     INDEX,
     INDICES,
diff --git a/server/src/main/java/org/opensearch/index/analysis/CharFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/CharFilterFactory.java
index 6d0ce067e5c48..dc9d3704b1a3c 100644
--- a/server/src/main/java/org/opensearch/index/analysis/CharFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/CharFilterFactory.java
@@ -34,6 +34,11 @@
 
 import java.io.Reader;
 
+/**
+ * Base character filter factory behavior used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public interface CharFilterFactory {
 
     String name();
diff --git a/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzer.java b/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzer.java
index 5971516520bbf..b0f4687c0b8b1 100644
--- a/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzer.java
@@ -35,10 +35,15 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.Reader;
 
+/**
+ * Custom analyzer chain
+ *
+ * @opensearch.internal
+ */
 public final class CustomAnalyzer extends Analyzer implements AnalyzerComponentsProvider {
 
     private final AnalyzerComponents components;
diff --git a/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzerProvider.java
index f300d7ad4330f..f339b6fc302bf 100644
--- a/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/CustomAnalyzerProvider.java
@@ -44,6 +44,8 @@
 /**
  * A custom analyzer that is built out of a single {@link org.apache.lucene.analysis.Tokenizer} and a list
  * of {@link org.apache.lucene.analysis.TokenFilter}s.
+ *
+ * @opensearch.internal
  */
 public class CustomAnalyzerProvider extends AbstractIndexAnalyzerProvider<Analyzer> {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/CustomMappingRuleParser.java b/server/src/main/java/org/opensearch/index/analysis/CustomMappingRuleParser.java
new file mode 100644
index 0000000000000..075c6ca1b585d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/analysis/CustomMappingRuleParser.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.analysis;
+
+import java.util.function.Function;
+
+/**
+ * A parser that takes a raw string and returns the parsed data of type T.
+ *
+ * @param <T> type of parsed data
+ */
+@FunctionalInterface
+public interface CustomMappingRuleParser<T> extends Function<String, T> {
+
+}
diff --git a/server/src/main/java/org/opensearch/index/analysis/CustomNormalizerProvider.java b/server/src/main/java/org/opensearch/index/analysis/CustomNormalizerProvider.java
index 4957ff4471f38..69c0cf418eece 100644
--- a/server/src/main/java/org/opensearch/index/analysis/CustomNormalizerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/CustomNormalizerProvider.java
@@ -43,6 +43,8 @@
  * A custom normalizer that is built out of a char and token filters. On the
  * contrary to analyzers, it does not support tokenizers and only supports a
  * subset of char and token filters.
+ *
+ * @opensearch.internal
  */
 public final class CustomNormalizerProvider extends AbstractIndexAnalyzerProvider<CustomAnalyzer> {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/FieldNameAnalyzer.java b/server/src/main/java/org/opensearch/index/analysis/FieldNameAnalyzer.java
index 26d1bf3ce73ca..14d4e89ab33b7 100644
--- a/server/src/main/java/org/opensearch/index/analysis/FieldNameAnalyzer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/FieldNameAnalyzer.java
@@ -38,6 +38,11 @@
 
 import java.util.Map;
 
+/**
+ * Analysis chain for field names
+ *
+ * @opensearch.internal
+ */
 public final class FieldNameAnalyzer extends DelegatingAnalyzerWrapper {
 
     private final Map<String, Analyzer> analyzers;
diff --git a/server/src/main/java/org/opensearch/index/analysis/HunspellTokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/HunspellTokenFilterFactory.java
index d195cbb57810a..dcfb77a90481d 100644
--- a/server/src/main/java/org/opensearch/index/analysis/HunspellTokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/HunspellTokenFilterFactory.java
@@ -40,6 +40,11 @@
 
 import java.util.Locale;
 
+/**
+ * The token filter factory for the hunspell analyzer
+ *
+ * @opensearch.internal
+ */
 public class HunspellTokenFilterFactory extends AbstractTokenFilterFactory {
 
     private final Dictionary dictionary;
diff --git a/server/src/main/java/org/opensearch/index/analysis/IndexAnalyzers.java b/server/src/main/java/org/opensearch/index/analysis/IndexAnalyzers.java
index a1c8f02765155..4d72ee48cf33a 100644
--- a/server/src/main/java/org/opensearch/index/analysis/IndexAnalyzers.java
+++ b/server/src/main/java/org/opensearch/index/analysis/IndexAnalyzers.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.index.analysis;
 
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -51,6 +51,8 @@
  * access to individual tokenizers, char or token filter.
  *
  * @see AnalysisRegistry
+ *
+ * @opensearch.internal
  */
 public final class IndexAnalyzers implements Closeable {
     private final Map<String, NamedAnalyzer> analyzers;
diff --git a/server/src/main/java/org/opensearch/index/analysis/KeywordAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/KeywordAnalyzerProvider.java
index 61580d07e1ba7..04ed3cf74f0ec 100644
--- a/server/src/main/java/org/opensearch/index/analysis/KeywordAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/KeywordAnalyzerProvider.java
@@ -37,6 +37,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Provider for the keyword analyzer
+ *
+ * @opensearch.internal
+ */
 public class KeywordAnalyzerProvider extends AbstractIndexAnalyzerProvider<KeywordAnalyzer> {
 
     private final KeywordAnalyzer keywordAnalyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizer.java b/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizer.java
index 4e9f1acfc530a..ca90244366da8 100644
--- a/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizer.java
@@ -38,7 +38,11 @@
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.core.KeywordTokenizer;
 
-/** Normalizer used to lowercase values */
+/**
+ * Normalizer used to lowercase values
+ *
+ * @opensearch.internal
+ */
 public final class LowercaseNormalizer extends Analyzer {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizerProvider.java b/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizerProvider.java
index 6b1f63b08ac70..bd6dce7ba69e9 100644
--- a/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/LowercaseNormalizerProvider.java
@@ -38,6 +38,8 @@
 
 /**
  * Builds an analyzer for normalization that lowercases terms.
+ *
+ * @opensearch.internal
  */
 public class LowercaseNormalizerProvider extends AbstractIndexAnalyzerProvider<LowercaseNormalizer> {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/MappingRule.java b/server/src/main/java/org/opensearch/index/analysis/MappingRule.java
new file mode 100644
index 0000000000000..92c9d2a17dc1e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/analysis/MappingRule.java
@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.analysis;
+
+/**
+ * Represents a mapping between two objects.
+ */
+public class MappingRule<L, R> {
+    private final L left;
+    private final R right;
+
+    public MappingRule(L left, R right) {
+        this.left = left;
+        this.right = right;
+    }
+
+    public L getLeft() {
+        return left;
+    }
+
+    public R getRight() {
+        return right;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/analysis/NameOrDefinition.java b/server/src/main/java/org/opensearch/index/analysis/NameOrDefinition.java
index c10a1ea66ac85..8bc5c2ce916be 100644
--- a/server/src/main/java/org/opensearch/index/analysis/NameOrDefinition.java
+++ b/server/src/main/java/org/opensearch/index/analysis/NameOrDefinition.java
@@ -32,19 +32,24 @@
 
 package org.opensearch.index.analysis;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Provides the name and settings for an analyzer
+ *
+ * @opensearch.internal
+ */
 public class NameOrDefinition implements Writeable, ToXContentFragment {
     // exactly one of these two members is not null
     public final String name;
diff --git a/server/src/main/java/org/opensearch/index/analysis/NamedAnalyzer.java b/server/src/main/java/org/opensearch/index/analysis/NamedAnalyzer.java
index 5ee904f196e2c..2a88d375a7df8 100644
--- a/server/src/main/java/org/opensearch/index/analysis/NamedAnalyzer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/NamedAnalyzer.java
@@ -43,6 +43,8 @@
 /**
  * Named analyzer is an analyzer wrapper around an actual analyzer ({@link #analyzer} that is associated
  * with a name ({@link #name()}.
+ *
+ * @opensearch.internal
  */
 public class NamedAnalyzer extends DelegatingAnalyzerWrapper {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/NormalizingCharFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/NormalizingCharFilterFactory.java
index e907800896dd3..ab8d23339029c 100644
--- a/server/src/main/java/org/opensearch/index/analysis/NormalizingCharFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/NormalizingCharFilterFactory.java
@@ -39,6 +39,8 @@
  *
  * The default implementation of {@link #normalize(Reader)} delegates to
  * {@link #create(Reader)}
+ *
+ * @opensearch.internal
  */
 public interface NormalizingCharFilterFactory extends CharFilterFactory {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/NormalizingTokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/NormalizingTokenFilterFactory.java
index 3cd6b6e0afd5d..be761aee0d36c 100644
--- a/server/src/main/java/org/opensearch/index/analysis/NormalizingTokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/NormalizingTokenFilterFactory.java
@@ -39,6 +39,8 @@
  *
  * The default implementation delegates {@link #normalize(TokenStream)} to
  * {@link #create(TokenStream)}}.
+ *
+ * @opensearch.internal
  */
 public interface NormalizingTokenFilterFactory extends TokenFilterFactory {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProvider.java
index ababa4a616efb..a6b4540760653 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProvider.java
@@ -34,6 +34,11 @@
 
 import org.apache.lucene.analysis.Analyzer;
 
+/**
+ * Provider for all prebuilt analyzers
+ *
+ * @opensearch.internal
+ */
 public class PreBuiltAnalyzerProvider implements AnalyzerProvider<NamedAnalyzer> {
 
     private final NamedAnalyzer analyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProviderFactory.java b/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProviderFactory.java
index d2c5384153bd2..a65e1898bea0d 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProviderFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreBuiltAnalyzerProviderFactory.java
@@ -34,8 +34,9 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.analysis.PreBuiltAnalyzers;
@@ -49,6 +50,11 @@
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
+/**
+ * Factory to create the providers for all prebuilt analyzers
+ *
+ * @opensearch.internal
+ */
 public class PreBuiltAnalyzerProviderFactory extends PreConfiguredAnalysisComponent<AnalyzerProvider<?>> implements Closeable {
 
     private final Function<Version, Analyzer> create;
@@ -72,7 +78,7 @@ public PreBuiltAnalyzerProviderFactory(String name, PreBuiltCacheFactory.Caching
     @Override
     public AnalyzerProvider<?> get(IndexSettings indexSettings, Environment environment, String name, Settings settings)
         throws IOException {
-        Version versionCreated = Version.indexCreated(settings);
+        Version versionCreated = IndexMetadata.indexCreated(settings);
         if (Version.CURRENT.equals(versionCreated) == false) {
             return super.get(indexSettings, environment, name, settings);
         } else {
@@ -99,6 +105,8 @@ public void close() throws IOException {
      *
      *  This can be removed when all analyzers have been moved away from PreBuiltAnalyzers to
      *  PreBuiltAnalyzerProviderFactory either in server or analysis-common.
+     *
+     * @opensearch.internal
      */
     static class PreBuiltAnalyzersDelegateCache implements PreBuiltCacheFactory.PreBuiltCache<AnalyzerProvider<?>> {
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredAnalysisComponent.java b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredAnalysisComponent.java
index 95437a2a8ef30..e6d607de3a0fb 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredAnalysisComponent.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredAnalysisComponent.java
@@ -33,6 +33,7 @@
 package org.opensearch.index.analysis;
 
 import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
@@ -43,6 +44,8 @@
 
 /**
  * Shared implementation for pre-configured analysis components.
+ *
+ * @opensearch.internal
  */
 public abstract class PreConfiguredAnalysisComponent<T> implements AnalysisModule.AnalysisProvider<T> {
     protected final String name;
@@ -60,7 +63,7 @@ protected PreConfiguredAnalysisComponent(String name, PreBuiltCacheFactory.PreBu
 
     @Override
     public T get(IndexSettings indexSettings, Environment environment, String name, Settings settings) throws IOException {
-        Version versionCreated = Version.indexCreated(settings);
+        Version versionCreated = IndexMetadata.indexCreated(settings);
         synchronized (this) {
             T factory = cache.get(versionCreated);
             if (factory == null) {
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredCharFilter.java b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredCharFilter.java
index a7faba4e4a7d8..6ba23ed67beed 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredCharFilter.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredCharFilter.java
@@ -43,6 +43,8 @@
 
 /**
  * Provides pre-configured, shared {@link CharFilter}s.
+ *
+ * @opensearch.internal
  */
 public class PreConfiguredCharFilter extends PreConfiguredAnalysisComponent<CharFilterFactory> {
     /**
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenFilter.java b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenFilter.java
index 23621f6c6480d..9fb8623994162 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenFilter.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenFilter.java
@@ -43,6 +43,8 @@
 
 /**
  * Provides pre-configured, shared {@link TokenFilter}s.
+ *
+ * @opensearch.internal
  */
 public final class PreConfiguredTokenFilter extends PreConfiguredAnalysisComponent<TokenFilterFactory> {
     /**
diff --git a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenizer.java b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenizer.java
index 428f386526813..50ff0a55add77 100644
--- a/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenizer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/PreConfiguredTokenizer.java
@@ -42,6 +42,8 @@
 
 /**
  * Provides pre-configured, shared {@link Tokenizer}s.
+ *
+ * @opensearch.internal
  */
 public final class PreConfiguredTokenizer extends PreConfiguredAnalysisComponent<TokenizerFactory> {
     /**
diff --git a/server/src/main/java/org/opensearch/index/analysis/ReloadableCustomAnalyzer.java b/server/src/main/java/org/opensearch/index/analysis/ReloadableCustomAnalyzer.java
index bd12f15693fbd..c1bfca93b90f7 100644
--- a/server/src/main/java/org/opensearch/index/analysis/ReloadableCustomAnalyzer.java
+++ b/server/src/main/java/org/opensearch/index/analysis/ReloadableCustomAnalyzer.java
@@ -37,11 +37,16 @@
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.util.CloseableThreadLocal;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.Reader;
 import java.util.Map;
 
+/**
+ * A custom analyzer that is reloadable
+ *
+ * @opensearch.internal
+ */
 public final class ReloadableCustomAnalyzer extends Analyzer implements AnalyzerComponentsProvider {
 
     private volatile AnalyzerComponents components;
diff --git a/server/src/main/java/org/opensearch/index/analysis/ShingleTokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/ShingleTokenFilterFactory.java
index 863c4b2611d66..701a9302fc164 100644
--- a/server/src/main/java/org/opensearch/index/analysis/ShingleTokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/ShingleTokenFilterFactory.java
@@ -41,6 +41,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Factory for shingle analyzer token filters
+ *
+ * @opensearch.internal
+ */
 public class ShingleTokenFilterFactory extends AbstractTokenFilterFactory {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(ShingleTokenFilterFactory.class);
@@ -116,6 +121,11 @@ public Factory getInnerFactory() {
         return this.factory;
     }
 
+    /**
+     * Factory for single token filter
+     *
+     * @opensearch.internal
+     */
     public static final class Factory implements TokenFilterFactory {
         private final int maxShingleSize;
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/SimpleAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/SimpleAnalyzerProvider.java
index 85d25aaa753e6..67b95a2849581 100644
--- a/server/src/main/java/org/opensearch/index/analysis/SimpleAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/SimpleAnalyzerProvider.java
@@ -37,6 +37,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Provider class for the simple analyzer
+ *
+ * @opensearch.internal
+ */
 public class SimpleAnalyzerProvider extends AbstractIndexAnalyzerProvider<SimpleAnalyzer> {
 
     private final SimpleAnalyzer simpleAnalyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/StandardAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/StandardAnalyzerProvider.java
index 1cdcb5af12c78..d7fe1bd9987b3 100644
--- a/server/src/main/java/org/opensearch/index/analysis/StandardAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/StandardAnalyzerProvider.java
@@ -38,6 +38,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Provider for the standard analyzer
+ *
+ * @opensearch.internal
+ */
 public class StandardAnalyzerProvider extends AbstractIndexAnalyzerProvider<StandardAnalyzer> {
 
     private final StandardAnalyzer standardAnalyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/StandardTokenizerFactory.java b/server/src/main/java/org/opensearch/index/analysis/StandardTokenizerFactory.java
index 4cb5b52280dfb..076be2497b98c 100644
--- a/server/src/main/java/org/opensearch/index/analysis/StandardTokenizerFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/StandardTokenizerFactory.java
@@ -39,6 +39,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Tokenizer factory for the standard analyzer
+ *
+ * @opensearch.internal
+ */
 public class StandardTokenizerFactory extends AbstractTokenizerFactory {
 
     private final int maxTokenLength;
diff --git a/server/src/main/java/org/opensearch/index/analysis/StopAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/StopAnalyzerProvider.java
index 84381c21cb8b4..41044d2afccf8 100644
--- a/server/src/main/java/org/opensearch/index/analysis/StopAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/StopAnalyzerProvider.java
@@ -39,6 +39,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Provider class for the stop word analyzer
+ *
+ * @opensearch.internal
+ */
 public class StopAnalyzerProvider extends AbstractIndexAnalyzerProvider<StopAnalyzer> {
 
     private final StopAnalyzer stopAnalyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/StopTokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/StopTokenFilterFactory.java
index 05787c1f4d95c..7ed0ec06a7c5f 100644
--- a/server/src/main/java/org/opensearch/index/analysis/StopTokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/StopTokenFilterFactory.java
@@ -43,6 +43,11 @@
 
 import java.util.Set;
 
+/**
+ * Token filter factory for the stop word analyzer
+ *
+ * @opensearch.internal
+ */
 public class StopTokenFilterFactory extends AbstractTokenFilterFactory {
 
     private final CharArraySet stopWords;
diff --git a/server/src/main/java/org/opensearch/index/analysis/TokenFilterFactory.java b/server/src/main/java/org/opensearch/index/analysis/TokenFilterFactory.java
index 3468fca095ed6..1b9d781b177ce 100644
--- a/server/src/main/java/org/opensearch/index/analysis/TokenFilterFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/TokenFilterFactory.java
@@ -39,6 +39,11 @@
 import java.util.List;
 import java.util.function.Function;
 
+/**
+ * Base token filter factory used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public interface TokenFilterFactory {
     String name();
 
diff --git a/server/src/main/java/org/opensearch/index/analysis/TokenizerFactory.java b/server/src/main/java/org/opensearch/index/analysis/TokenizerFactory.java
index d38c1f9c3027a..b667175e89b4a 100644
--- a/server/src/main/java/org/opensearch/index/analysis/TokenizerFactory.java
+++ b/server/src/main/java/org/opensearch/index/analysis/TokenizerFactory.java
@@ -36,6 +36,11 @@
 
 import java.util.function.Supplier;
 
+/**
+ * Base tokenizer factory used in analysis chain
+ *
+ * @opensearch.internal
+ */
 public interface TokenizerFactory {
 
     String name();
diff --git a/server/src/main/java/org/opensearch/index/analysis/WhitespaceAnalyzerProvider.java b/server/src/main/java/org/opensearch/index/analysis/WhitespaceAnalyzerProvider.java
index 63425af2d23f5..038b9168745da 100644
--- a/server/src/main/java/org/opensearch/index/analysis/WhitespaceAnalyzerProvider.java
+++ b/server/src/main/java/org/opensearch/index/analysis/WhitespaceAnalyzerProvider.java
@@ -37,6 +37,11 @@
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Provider class for the whitespace analyzer
+ *
+ * @opensearch.internal
+ */
 public class WhitespaceAnalyzerProvider extends AbstractIndexAnalyzerProvider<WhitespaceAnalyzer> {
 
     private final WhitespaceAnalyzer analyzer;
diff --git a/server/src/main/java/org/opensearch/index/analysis/package-info.java b/server/src/main/java/org/opensearch/index/analysis/package-info.java
new file mode 100644
index 0000000000000..28cd10ffae0ab
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/analysis/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing analysis operations */
+package org.opensearch.index.analysis;
diff --git a/server/src/main/java/org/opensearch/index/cache/IndexCache.java b/server/src/main/java/org/opensearch/index/cache/IndexCache.java
index ff8be98cd8ab4..90462e9919970 100644
--- a/server/src/main/java/org/opensearch/index/cache/IndexCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/IndexCache.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.cache;
 
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
@@ -41,6 +41,11 @@
 import java.io.Closeable;
 import java.io.IOException;
 
+/**
+ * Wrapping class for the index cache
+ *
+ * @opensearch.internal
+ */
 public class IndexCache extends AbstractIndexComponent implements Closeable {
 
     private final QueryCache queryCache;
diff --git a/server/src/main/java/org/opensearch/index/cache/bitset/BitsetFilterCache.java b/server/src/main/java/org/opensearch/index/cache/bitset/BitsetFilterCache.java
index 0bc77f0f0079b..bd9074f77c196 100644
--- a/server/src/main/java/org/opensearch/index/cache/bitset/BitsetFilterCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/bitset/BitsetFilterCache.java
@@ -57,6 +57,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.IndexWarmer;
@@ -65,7 +66,6 @@
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardUtils;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -84,6 +84,8 @@
  * Use this cache with care, only components that require that a filter is to be materialized as a {@link BitDocIdSet}
  * and require that it should always be around should use this cache, otherwise the
  * {@link org.opensearch.index.cache.query.QueryCache} should be used instead.
+ *
+ * @opensearch.internal
  */
 public final class BitsetFilterCache extends AbstractIndexComponent
     implements
@@ -190,6 +192,11 @@ public void onRemoval(RemovalNotification<IndexReader.CacheKey, Cache<Query, Val
         }
     }
 
+    /**
+     * Value for bitset filter cache
+     *
+     * @opensearch.internal
+     */
     public static final class Value {
 
         final BitSet bitset;
@@ -314,6 +321,8 @@ Cache<IndexReader.CacheKey, Cache<Query, Value>> getLoadedFilters() {
 
     /**
      *  A listener interface that is executed for each onCache / onRemoval event
+     *
+     * @opensearch.internal
      */
     public interface Listener {
         /**
diff --git a/server/src/main/java/org/opensearch/index/cache/bitset/ShardBitsetFilterCache.java b/server/src/main/java/org/opensearch/index/cache/bitset/ShardBitsetFilterCache.java
index 3ddadc0cdedba..5bd3ea2c13e18 100644
--- a/server/src/main/java/org/opensearch/index/cache/bitset/ShardBitsetFilterCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/bitset/ShardBitsetFilterCache.java
@@ -33,10 +33,15 @@
 package org.opensearch.index.cache.bitset;
 
 import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.AbstractIndexShardComponent;
-import org.opensearch.index.shard.ShardId;
 
+/**
+ * Bitset Filter Cache for shards
+ *
+ * @opensearch.internal
+ */
 public class ShardBitsetFilterCache extends AbstractIndexShardComponent {
 
     private final CounterMetric totalMetric = new CounterMetric();
diff --git a/server/src/main/java/org/opensearch/index/cache/bitset/package-info.java b/server/src/main/java/org/opensearch/index/cache/bitset/package-info.java
new file mode 100644
index 0000000000000..cb15224dd7613
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/cache/bitset/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all bitset operations for indexing cache */
+package org.opensearch.index.cache.bitset;
diff --git a/server/src/main/java/org/opensearch/index/cache/package-info.java b/server/src/main/java/org/opensearch/index/cache/package-info.java
new file mode 100644
index 0000000000000..6ea72a6e17f83
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/cache/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing cache operations */
+package org.opensearch.index.cache;
diff --git a/server/src/main/java/org/opensearch/index/cache/query/DisabledQueryCache.java b/server/src/main/java/org/opensearch/index/cache/query/DisabledQueryCache.java
index 8a25f731adb03..493d8a4bbcd98 100644
--- a/server/src/main/java/org/opensearch/index/cache/query/DisabledQueryCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/query/DisabledQueryCache.java
@@ -37,6 +37,11 @@
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * NoOp Implementation for a Disabled query cache
+ *
+ * @opensearch.internal
+ */
 public class DisabledQueryCache extends AbstractIndexComponent implements QueryCache {
 
     public DisabledQueryCache(IndexSettings indexSettings) {
diff --git a/server/src/main/java/org/opensearch/index/cache/query/IndexQueryCache.java b/server/src/main/java/org/opensearch/index/cache/query/IndexQueryCache.java
index b410f8d83df8c..c69f0b8da068f 100644
--- a/server/src/main/java/org/opensearch/index/cache/query/IndexQueryCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/query/IndexQueryCache.java
@@ -42,6 +42,8 @@
 /**
  * The index-level query cache. This class mostly delegates to the node-level
  * query cache: {@link IndicesQueryCache}.
+ *
+ * @opensearch.internal
  */
 public class IndexQueryCache extends AbstractIndexComponent implements QueryCache {
 
diff --git a/server/src/main/java/org/opensearch/index/cache/query/QueryCache.java b/server/src/main/java/org/opensearch/index/cache/query/QueryCache.java
index fe38c61dfe54c..384f66fcfc132 100644
--- a/server/src/main/java/org/opensearch/index/cache/query/QueryCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/query/QueryCache.java
@@ -36,6 +36,11 @@
 
 import java.io.Closeable;
 
+/**
+ * Base interface for a query cache
+ *
+ * @opensearch.internal
+ */
 public interface QueryCache extends IndexComponent, Closeable, org.apache.lucene.search.QueryCache {
 
     void clear(String reason);
diff --git a/server/src/main/java/org/opensearch/index/cache/query/QueryCacheStats.java b/server/src/main/java/org/opensearch/index/cache/query/QueryCacheStats.java
index 9dcae1f93d537..88077aafb1495 100644
--- a/server/src/main/java/org/opensearch/index/cache/query/QueryCacheStats.java
+++ b/server/src/main/java/org/opensearch/index/cache/query/QueryCacheStats.java
@@ -33,16 +33,21 @@
 package org.opensearch.index.cache.query;
 
 import org.apache.lucene.search.DocIdSet;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats for the query cache
+ *
+ * @opensearch.internal
+ */
 public class QueryCacheStats implements Writeable, ToXContentFragment {
 
     private long ramBytesUsed;
@@ -150,6 +155,11 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
         return builder;
     }
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String QUERY_CACHE = "query_cache";
         static final String MEMORY_SIZE = "memory_size";
diff --git a/server/src/main/java/org/opensearch/index/cache/query/package-info.java b/server/src/main/java/org/opensearch/index/cache/query/package-info.java
new file mode 100644
index 0000000000000..4843b1fb5c29b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/cache/query/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all query cache operations */
+package org.opensearch.index.cache.query;
diff --git a/server/src/main/java/org/opensearch/index/cache/request/RequestCacheStats.java b/server/src/main/java/org/opensearch/index/cache/request/RequestCacheStats.java
index f48f442af1390..24f68899c2ac7 100644
--- a/server/src/main/java/org/opensearch/index/cache/request/RequestCacheStats.java
+++ b/server/src/main/java/org/opensearch/index/cache/request/RequestCacheStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.cache.request;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Request for the query cache statistics
+ *
+ * @opensearch.internal
+ */
 public class RequestCacheStats implements Writeable, ToXContentFragment {
 
     private long memorySize;
@@ -110,6 +115,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String REQUEST_CACHE_STATS = "request_cache";
         static final String MEMORY_SIZE = "memory_size";
diff --git a/server/src/main/java/org/opensearch/index/cache/request/ShardRequestCache.java b/server/src/main/java/org/opensearch/index/cache/request/ShardRequestCache.java
index 5fb6d48c74c87..b13eec79c2be8 100644
--- a/server/src/main/java/org/opensearch/index/cache/request/ShardRequestCache.java
+++ b/server/src/main/java/org/opensearch/index/cache/request/ShardRequestCache.java
@@ -33,11 +33,13 @@
 package org.opensearch.index.cache.request;
 
 import org.apache.lucene.util.Accountable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.core.common.bytes.BytesReference;
 
 /**
  * Tracks the portion of the request cache in use for a particular shard.
+ *
+ * @opensearch.internal
  */
 public final class ShardRequestCache {
 
diff --git a/server/src/main/java/org/opensearch/index/cache/request/package-info.java b/server/src/main/java/org/opensearch/index/cache/request/package-info.java
new file mode 100644
index 0000000000000..d88c79d17b9fd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/cache/request/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core transport classes responsible for handling all indexing cache requests */
+package org.opensearch.index.cache.request;
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecAliases.java b/server/src/main/java/org/opensearch/index/codec/CodecAliases.java
new file mode 100644
index 0000000000000..066c092e86db8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/codec/CodecAliases.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.codec;
+
+import org.apache.lucene.codecs.Codec;
+import org.opensearch.common.annotation.ExperimentalApi;
+
+import java.util.Set;
+
+/**
+ * This {@link CodecAliases} to provide aliases for the {@link Codec}.
+ *
+ * @opensearch.internal
+ */
+@ExperimentalApi
+public interface CodecAliases {
+
+    /**
+     * Retrieves a set of aliases for an codec.
+     *
+     * @return A non-null set of alias strings. If no aliases are available, an empty set should be returned.
+     */
+    default Set<String> aliases() {
+        return Set.of();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecService.java b/server/src/main/java/org/opensearch/index/codec/CodecService.java
index e445ad88f497e..9b57fe64cbeab 100644
--- a/server/src/main/java/org/opensearch/index/codec/CodecService.java
+++ b/server/src/main/java/org/opensearch/index/codec/CodecService.java
@@ -34,10 +34,11 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.codecs.Codec;
-import org.apache.lucene.codecs.lucene91.Lucene91Codec;
-import org.apache.lucene.codecs.lucene91.Lucene91Codec.Mode;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec.Mode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
 
 import java.util.Map;
@@ -47,22 +48,51 @@
  * codec layer that allows to use use-case specific file formats &amp;
  * data-structures per field. OpenSearch exposes the full
  * {@link Codec} capabilities through this {@link CodecService}.
+ *
+ * @opensearch.internal
  */
 public class CodecService {
 
     private final Map<String, Codec> codecs;
 
     public static final String DEFAULT_CODEC = "default";
+    public static final String LZ4 = "lz4";
     public static final String BEST_COMPRESSION_CODEC = "best_compression";
-    /** the raw unfiltered lucene default. useful for testing */
+    public static final String ZLIB = "zlib";
+    /**
+     * the raw unfiltered lucene default. useful for testing
+     */
     public static final String LUCENE_DEFAULT_CODEC = "lucene_default";
 
+    public CodecService(@Nullable MapperService mapperService, IndexSettings indexSettings, Logger logger) {
+        final MapBuilder<String, Codec> codecs = MapBuilder.<String, Codec>newMapBuilder();
+        assert null != indexSettings;
+        if (mapperService == null) {
+            codecs.put(DEFAULT_CODEC, new Lucene95Codec());
+            codecs.put(LZ4, new Lucene95Codec());
+            codecs.put(BEST_COMPRESSION_CODEC, new Lucene95Codec(Mode.BEST_COMPRESSION));
+            codecs.put(ZLIB, new Lucene95Codec(Mode.BEST_COMPRESSION));
+        } else {
+            codecs.put(DEFAULT_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
+            codecs.put(LZ4, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
+            codecs.put(BEST_COMPRESSION_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
+            codecs.put(ZLIB, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
+        }
+        codecs.put(LUCENE_DEFAULT_CODEC, Codec.getDefault());
+        for (String codec : Codec.availableCodecs()) {
+            codecs.put(codec, Codec.forName(codec));
+        }
+        this.codecs = codecs.immutableMap();
+    }
+
+    @Deprecated(since = "2.9.0", forRemoval = true)
     public CodecService(@Nullable MapperService mapperService, Logger logger) {
         final MapBuilder<String, Codec> codecs = MapBuilder.<String, Codec>newMapBuilder();
         if (mapperService == null) {
-            codecs.put(DEFAULT_CODEC, new Lucene91Codec());
-            codecs.put(BEST_COMPRESSION_CODEC, new Lucene91Codec(Mode.BEST_COMPRESSION));
+            codecs.put(DEFAULT_CODEC, new Lucene95Codec());
+            codecs.put(BEST_COMPRESSION_CODEC, new Lucene95Codec(Mode.BEST_COMPRESSION));
         } else {
+            IndexSettings indexSettings = mapperService.getIndexSettings();
             codecs.put(DEFAULT_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
             codecs.put(BEST_COMPRESSION_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
         }
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecServiceConfig.java b/server/src/main/java/org/opensearch/index/codec/CodecServiceConfig.java
index 313c0d359bb02..5fa9261471acf 100644
--- a/server/src/main/java/org/opensearch/index/codec/CodecServiceConfig.java
+++ b/server/src/main/java/org/opensearch/index/codec/CodecServiceConfig.java
@@ -17,6 +17,8 @@
 
 /**
  * The configuration parameters necessary for the {@link CodecService} instance construction.
+ *
+ * @opensearch.internal
  */
 public final class CodecServiceConfig {
     private final IndexSettings indexSettings;
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecServiceFactory.java b/server/src/main/java/org/opensearch/index/codec/CodecServiceFactory.java
index da28c5f06b035..8f60d1a045330 100644
--- a/server/src/main/java/org/opensearch/index/codec/CodecServiceFactory.java
+++ b/server/src/main/java/org/opensearch/index/codec/CodecServiceFactory.java
@@ -10,6 +10,8 @@
 
 /**
  * A factory for creating new {@link CodecService} instance
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface CodecServiceFactory {
diff --git a/server/src/main/java/org/opensearch/index/codec/CodecSettings.java b/server/src/main/java/org/opensearch/index/codec/CodecSettings.java
new file mode 100644
index 0000000000000..2d371dfc190db
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/codec/CodecSettings.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.codec;
+
+import org.apache.lucene.codecs.Codec;
+import org.opensearch.common.settings.Setting;
+
+/**
+ * This {@link CodecSettings} allows us to manage the settings with {@link Codec}.
+ *
+ * @opensearch.internal
+ */
+public interface CodecSettings {
+    boolean supports(Setting<?> setting);
+}
diff --git a/server/src/main/java/org/opensearch/index/codec/PerFieldMappingPostingFormatCodec.java b/server/src/main/java/org/opensearch/index/codec/PerFieldMappingPostingFormatCodec.java
index fa01390d13419..d3207557273a5 100644
--- a/server/src/main/java/org/opensearch/index/codec/PerFieldMappingPostingFormatCodec.java
+++ b/server/src/main/java/org/opensearch/index/codec/PerFieldMappingPostingFormatCodec.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.codecs.DocValuesFormat;
 import org.apache.lucene.codecs.PostingsFormat;
-import org.apache.lucene.codecs.lucene91.Lucene91Codec;
 import org.apache.lucene.codecs.lucene90.Lucene90DocValuesFormat;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -50,8 +50,10 @@
  * allows users to change the low level postings format for individual fields
  * per index in real time via the mapping API. If no specific postings format is
  * configured for a specific field the default postings format is used.
+ *
+ * @opensearch.internal
  */
-public class PerFieldMappingPostingFormatCodec extends Lucene91Codec {
+public class PerFieldMappingPostingFormatCodec extends Lucene95Codec {
     private final Logger logger;
     private final MapperService mapperService;
     private final DocValuesFormat dvFormat = new Lucene90DocValuesFormat();
diff --git a/server/src/main/java/org/opensearch/index/codec/package-info.java b/server/src/main/java/org/opensearch/index/codec/package-info.java
new file mode 100644
index 0000000000000..2f96ecea4f434
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/codec/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all codec service and operations */
+package org.opensearch.index.codec;
diff --git a/server/src/main/java/org/opensearch/index/document/SortedUnsignedLongDocValuesRangeQuery.java b/server/src/main/java/org/opensearch/index/document/SortedUnsignedLongDocValuesRangeQuery.java
new file mode 100644
index 0000000000000..234c67cc637f1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/document/SortedUnsignedLongDocValuesRangeQuery.java
@@ -0,0 +1,170 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.document;
+
+import org.apache.lucene.index.DocValues;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NumericDocValues;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.search.ConstantScoreScorer;
+import org.apache.lucene.search.ConstantScoreWeight;
+import org.apache.lucene.search.FieldExistsQuery;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.QueryVisitor;
+import org.apache.lucene.search.ScoreMode;
+import org.apache.lucene.search.Scorer;
+import org.apache.lucene.search.TwoPhaseIterator;
+import org.apache.lucene.search.Weight;
+import org.opensearch.common.Numbers;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.Objects;
+
+/**
+ * The {@link org.apache.lucene.document.SortedNumericDocValuesRangeQuery} implementation for unsigned long numeric data type.
+ *
+ * @opensearch.internal
+ */
+public abstract class SortedUnsignedLongDocValuesRangeQuery extends Query {
+    private final String field;
+    private final long lowerValue;
+    private final long upperValue;
+
+    SortedUnsignedLongDocValuesRangeQuery(String field, BigInteger lowerValue, BigInteger upperValue) {
+        this.field = Objects.requireNonNull(field);
+        this.lowerValue = lowerValue.longValue();
+        this.upperValue = upperValue.longValue();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (sameClassAs(obj) == false) {
+            return false;
+        }
+        SortedUnsignedLongDocValuesRangeQuery that = (SortedUnsignedLongDocValuesRangeQuery) obj;
+        return Objects.equals(field, that.field) && lowerValue == that.lowerValue && upperValue == that.upperValue;
+    }
+
+    @Override
+    public int hashCode() {
+        int h = classHash();
+        h = 31 * h + field.hashCode();
+        h = 31 * h + Long.hashCode(lowerValue);
+        h = 31 * h + Long.hashCode(upperValue);
+        return h;
+    }
+
+    @Override
+    public void visit(QueryVisitor visitor) {
+        if (visitor.acceptField(field)) {
+            visitor.visitLeaf(this);
+        }
+    }
+
+    @Override
+    public String toString(String field) {
+        StringBuilder b = new StringBuilder();
+        if (this.field.equals(field) == false) {
+            b.append(this.field).append(":");
+        }
+        return b.append("[")
+            .append(Long.toUnsignedString(lowerValue))
+            .append(" TO ")
+            .append(Long.toUnsignedString(upperValue))
+            .append("]")
+            .toString();
+    }
+
+    @Override
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        if (Long.compareUnsigned(lowerValue, Numbers.MIN_UNSIGNED_LONG_VALUE_AS_LONG) == 0
+            && Long.compareUnsigned(upperValue, Numbers.MAX_UNSIGNED_LONG_VALUE_AS_LONG) == 0) {
+            return new FieldExistsQuery(field);
+        }
+        return super.rewrite(searcher);
+    }
+
+    abstract SortedNumericDocValues getValues(LeafReader reader, String field) throws IOException;
+
+    @Override
+    public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException {
+        return new ConstantScoreWeight(this, boost) {
+
+            @Override
+            public boolean isCacheable(LeafReaderContext ctx) {
+                return DocValues.isCacheable(ctx, field);
+            }
+
+            @Override
+            public Scorer scorer(LeafReaderContext context) throws IOException {
+                SortedNumericDocValues values = getValues(context.reader(), field);
+                if (values == null) {
+                    return null;
+                }
+                final NumericDocValues singleton = DocValues.unwrapSingleton(values);
+                final TwoPhaseIterator iterator;
+                if (singleton != null) {
+                    iterator = new TwoPhaseIterator(singleton) {
+                        @Override
+                        public boolean matches() throws IOException {
+                            final long value = singleton.longValue();
+                            return Long.compareUnsigned(value, lowerValue) >= 0 && Long.compareUnsigned(value, upperValue) <= 0;
+                        }
+
+                        @Override
+                        public float matchCost() {
+                            return 2; // 2 comparisons
+                        }
+                    };
+                } else {
+                    iterator = new TwoPhaseIterator(values) {
+                        @Override
+                        public boolean matches() throws IOException {
+                            for (int i = 0, count = values.docValueCount(); i < count; ++i) {
+                                final long value = values.nextValue();
+                                if (Long.compareUnsigned(value, lowerValue) < 0) {
+                                    continue;
+                                }
+                                // Values are sorted, so the first value that is >= lowerValue is our best
+                                // candidate
+                                return Long.compareUnsigned(value, upperValue) <= 0;
+                            }
+                            return false; // all values were < lowerValue
+                        }
+
+                        @Override
+                        public float matchCost() {
+                            return 2; // 2 comparisons
+                        }
+                    };
+                }
+                return new ConstantScoreScorer(this, score(), scoreMode, iterator);
+            }
+        };
+    }
+
+    public static Query newSlowRangeQuery(String field, BigInteger lowerValue, BigInteger upperValue) {
+        return new SortedUnsignedLongDocValuesRangeQuery(field, lowerValue, upperValue) {
+            @Override
+            SortedNumericDocValues getValues(LeafReader reader, String field) throws IOException {
+                FieldInfo info = reader.getFieldInfos().fieldInfo(field);
+                if (info == null) {
+                    // Queries have some optimizations when one sub scorer returns null rather
+                    // than a scorer that does not match any documents
+                    return null;
+                }
+                return DocValues.getSortedNumeric(reader, field);
+            }
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/document/package-info.java b/server/src/main/java/org/opensearch/index/document/package-info.java
new file mode 100644
index 0000000000000..5f09feae168d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/document/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing OpenSearch document queries */
+package org.opensearch.index.document;
diff --git a/server/src/main/java/org/opensearch/index/engine/CombinedDeletionPolicy.java b/server/src/main/java/org/opensearch/index/engine/CombinedDeletionPolicy.java
index 09e6599b33409..4d7faf6c9e375 100644
--- a/server/src/main/java/org/opensearch/index/engine/CombinedDeletionPolicy.java
+++ b/server/src/main/java/org/opensearch/index/engine/CombinedDeletionPolicy.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.engine;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexDeletionPolicy;
@@ -45,6 +44,7 @@
 import java.io.IOException;
 import java.nio.file.Path;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -56,13 +56,15 @@
  * <p>
  * In particular, this policy will delete index commits whose max sequence number is at most
  * the current global checkpoint except the index commit which has the highest max sequence number among those.
+ *
+ * @opensearch.internal
  */
 public class CombinedDeletionPolicy extends IndexDeletionPolicy {
     private final Logger logger;
     private final TranslogDeletionPolicy translogDeletionPolicy;
     private final SoftDeletesPolicy softDeletesPolicy;
     private final LongSupplier globalCheckpointSupplier;
-    private final ObjectIntHashMap<IndexCommit> snapshottedCommits; // Number of snapshots held against each commit point.
+    private final Map<IndexCommit, Integer> snapshottedCommits; // Number of snapshots held against each commit point.
     private volatile IndexCommit safeCommit; // the most recent safe commit point - its max_seqno at most the persisted global checkpoint.
     private volatile long maxSeqNoOfNextSafeCommit;
     private volatile IndexCommit lastCommit; // the most recent commit point
@@ -78,7 +80,7 @@ public class CombinedDeletionPolicy extends IndexDeletionPolicy {
         this.translogDeletionPolicy = translogDeletionPolicy;
         this.softDeletesPolicy = softDeletesPolicy;
         this.globalCheckpointSupplier = globalCheckpointSupplier;
-        this.snapshottedCommits = new ObjectIntHashMap<>();
+        this.snapshottedCommits = new HashMap<>();
     }
 
     @Override
@@ -172,7 +174,7 @@ synchronized IndexCommit acquireIndexCommit(boolean acquiringSafeCommit) {
         assert safeCommit != null : "Safe commit is not initialized yet";
         assert lastCommit != null : "Last commit is not initialized yet";
         final IndexCommit snapshotting = acquiringSafeCommit ? safeCommit : lastCommit;
-        snapshottedCommits.addTo(snapshotting, 1); // increase refCount
+        snapshottedCommits.merge(snapshotting, 1, Integer::sum); // increase refCount
         return new SnapshotIndexCommit(snapshotting);
     }
 
@@ -189,7 +191,7 @@ synchronized boolean releaseCommit(final IndexCommit snapshotCommit) {
             + "], releasing commit ["
             + releasingCommit
             + "]";
-        final int refCount = snapshottedCommits.addTo(releasingCommit, -1); // release refCount
+        final int refCount = snapshottedCommits.merge(releasingCommit, -1, Integer::sum); // release refCount
         assert refCount >= 0 : "Number of snapshots can not be negative [" + refCount + "]";
         if (refCount == 0) {
             snapshottedCommits.remove(releasingCommit);
@@ -263,6 +265,8 @@ public static String commitDescription(IndexCommit commit) throws IOException {
 
     /**
      * A wrapper of an index commit that prevents it from being deleted.
+     *
+     * @opensearch.internal
      */
     private static class SnapshotIndexCommit extends IndexCommit {
         private final IndexCommit delegate;
diff --git a/server/src/main/java/org/opensearch/index/engine/CombinedDocValues.java b/server/src/main/java/org/opensearch/index/engine/CombinedDocValues.java
index 043e4f2d5661f..0f8ca53429a81 100644
--- a/server/src/main/java/org/opensearch/index/engine/CombinedDocValues.java
+++ b/server/src/main/java/org/opensearch/index/engine/CombinedDocValues.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Doc Values used in LuceneChangesSnapshot for recovery
+ *
+ * @opensearch.internal
+ */
 final class CombinedDocValues {
     private final NumericDocValues versionDV;
     private final NumericDocValues seqNoDV;
diff --git a/server/src/main/java/org/opensearch/index/engine/CommitStats.java b/server/src/main/java/org/opensearch/index/engine/CommitStats.java
index 1220208d3a8f3..4328ebed85aa1 100644
--- a/server/src/main/java/org/opensearch/index/engine/CommitStats.java
+++ b/server/src/main/java/org/opensearch/index/engine/CommitStats.java
@@ -33,18 +33,22 @@
 
 import org.apache.lucene.index.SegmentInfos;
 import org.opensearch.common.collect.MapBuilder;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Base64;
 import java.util.Map;
 
-/** a class the returns dynamic information with respect to the last commit point of this shard */
+/**
+ * a class the returns dynamic information with respect to the last commit point of this shard
+ *
+ * @opensearch.internal
+ */
 public final class CommitStats implements Writeable, ToXContentFragment {
 
     private final Map<String, String> userData;
@@ -108,6 +112,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeInt(numDocs);
     }
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String GENERATION = "generation";
         static final String USER_DATA = "user_data";
diff --git a/server/src/main/java/org/opensearch/index/engine/CompletionStatsCache.java b/server/src/main/java/org/opensearch/index/engine/CompletionStatsCache.java
index b37572a280b4c..99f80df376df9 100644
--- a/server/src/main/java/org/opensearch/index/engine/CompletionStatsCache.java
+++ b/server/src/main/java/org/opensearch/index/engine/CompletionStatsCache.java
@@ -31,24 +31,29 @@
 
 package org.opensearch.index.engine;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
-import com.carrotsearch.hppc.cursors.ObjectLongCursor;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.search.ReferenceManager;
 import org.apache.lucene.search.suggest.document.CompletionTerms;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.search.suggest.completion.CompletionStats;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.function.Supplier;
 
+/**
+ * Cache to store engine completion stats
+ *
+ * @opensearch.internal
+ */
 class CompletionStatsCache implements ReferenceManager.RefreshListener {
 
     private final Supplier<Engine.Searcher> searcherSupplier;
@@ -94,7 +99,7 @@ CompletionStats get(String... fieldNamePatterns) {
         // we won the race, nobody else is already computing stats, so it's up to us
         ActionListener.completeWith(newFuture, () -> {
             long sizeInBytes = 0;
-            final ObjectLongHashMap<String> completionFields = new ObjectLongHashMap<>();
+            final Map<String, Long> completionFields = new HashMap<>();
 
             try (Engine.Searcher currentSearcher = searcherSupplier.get()) {
                 for (LeafReaderContext atomicReaderContext : currentSearcher.getIndexReader().leaves()) {
@@ -104,7 +109,7 @@ CompletionStats get(String... fieldNamePatterns) {
                         if (terms instanceof CompletionTerms) {
                             // TODO: currently we load up the suggester for reporting its size
                             final long fstSize = ((CompletionTerms) terms).suggester().ramBytesUsed();
-                            completionFields.addTo(info.name, fstSize);
+                            completionFields.merge(info.name, fstSize, Long::sum);
                             sizeInBytes += fstSize;
                         }
                     }
@@ -138,10 +143,10 @@ CompletionStats get(String... fieldNamePatterns) {
     private static CompletionStats filterCompletionStatsByFieldName(String[] fieldNamePatterns, CompletionStats fullCompletionStats) {
         final FieldMemoryStats fieldMemoryStats;
         if (CollectionUtils.isEmpty(fieldNamePatterns) == false) {
-            final ObjectLongHashMap<String> completionFields = new ObjectLongHashMap<>(fieldNamePatterns.length);
-            for (ObjectLongCursor<String> fieldCursor : fullCompletionStats.getFields()) {
-                if (Regex.simpleMatch(fieldNamePatterns, fieldCursor.key)) {
-                    completionFields.addTo(fieldCursor.key, fieldCursor.value);
+            final Map<String, Long> completionFields = new HashMap<>(fieldNamePatterns.length);
+            for (var fieldCursor : fullCompletionStats.getFields()) {
+                if (Regex.simpleMatch(fieldNamePatterns, fieldCursor.getKey())) {
+                    completionFields.merge(fieldCursor.getKey(), fieldCursor.getValue(), Long::sum);
                 }
             }
             fieldMemoryStats = new FieldMemoryStats(completionFields);
diff --git a/server/src/main/java/org/opensearch/index/engine/DeleteVersionValue.java b/server/src/main/java/org/opensearch/index/engine/DeleteVersionValue.java
index 8ee700428bcb4..9926f3762626f 100644
--- a/server/src/main/java/org/opensearch/index/engine/DeleteVersionValue.java
+++ b/server/src/main/java/org/opensearch/index/engine/DeleteVersionValue.java
@@ -34,7 +34,11 @@
 
 import org.apache.lucene.util.RamUsageEstimator;
 
-/** Holds a deleted version, which just adds a timestamp to {@link VersionValue} so we know when we can expire the deletion. */
+/**
+ * Holds a deleted version, which just adds a timestamp to {@link VersionValue} so we know when we can expire the deletion.
+ *
+ * @opensearch.internal
+ */
 
 final class DeleteVersionValue extends VersionValue {
 
diff --git a/server/src/main/java/org/opensearch/index/engine/DocumentMissingException.java b/server/src/main/java/org/opensearch/index/engine/DocumentMissingException.java
index 9eb54292e13bd..350db5c9bc795 100644
--- a/server/src/main/java/org/opensearch/index/engine/DocumentMissingException.java
+++ b/server/src/main/java/org/opensearch/index/engine/DocumentMissingException.java
@@ -31,12 +31,17 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a document is missing
+ *
+ * @opensearch.internal
+ */
 public class DocumentMissingException extends EngineException {
 
     public DocumentMissingException(ShardId shardId, String id) {
diff --git a/server/src/main/java/org/opensearch/index/engine/DocumentSourceMissingException.java b/server/src/main/java/org/opensearch/index/engine/DocumentSourceMissingException.java
index 333abc3794a5c..0fafbb413bbeb 100644
--- a/server/src/main/java/org/opensearch/index/engine/DocumentSourceMissingException.java
+++ b/server/src/main/java/org/opensearch/index/engine/DocumentSourceMissingException.java
@@ -31,12 +31,17 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a document source is missing
+ *
+ * @opensearch.internal
+ */
 public class DocumentSourceMissingException extends EngineException {
 
     public DocumentSourceMissingException(ShardId shardId, String id) {
diff --git a/server/src/main/java/org/opensearch/index/engine/Engine.java b/server/src/main/java/org/opensearch/index/engine/Engine.java
index bba1d8c069c68..cf83a9808ee56 100644
--- a/server/src/main/java/org/opensearch/index/engine/Engine.java
+++ b/server/src/main/java/org/opensearch/index/engine/Engine.java
@@ -38,49 +38,60 @@
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.SegmentCommitInfo;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.SegmentReader;
+import org.apache.lucene.index.StandardDirectoryReader;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.QueryCache;
 import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.ReferenceManager;
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver;
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndVersion;
 import org.opensearch.common.metrics.CounterMetric;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.VersionType;
+import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.Mapping;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.index.mapper.ParsedDocument;
+import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.merge.MergeStats;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.DocsStats;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.TranslogDeletionPolicy;
 import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.search.suggest.completion.CompletionStats;
 
@@ -90,6 +101,7 @@
 import java.io.UncheckedIOException;
 import java.nio.file.NoSuchFileException;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -112,6 +124,11 @@
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 
+/**
+ * Base OpenSearch Engine class
+ *
+ * @opensearch.internal
+ */
 public abstract class Engine implements Closeable {
 
     public static final String SYNC_COMMIT_ID = "sync_id";  // TODO: remove sync_id in 3.0
@@ -121,12 +138,15 @@ public abstract class Engine implements Closeable {
     public static final String MAX_UNSAFE_AUTO_ID_TIMESTAMP_COMMIT_ID = "max_unsafe_auto_id_timestamp";
     public static final String SEARCH_SOURCE = "search"; // TODO: Make source of search enum?
     public static final String CAN_MATCH_SEARCH_SOURCE = "can_match";
+    public static final String FORCE_MERGE = "force merge";
+    public static final String MERGE_FAILED = "merge failed";
 
     protected final ShardId shardId;
     protected final Logger logger;
     protected final EngineConfig engineConfig;
     protected final Store store;
     protected final AtomicBoolean isClosed = new AtomicBoolean(false);
+    private final CounterMetric totalUnreferencedFileCleanUpsPerformed = new CounterMetric();
     private final CountDownLatch closedLatch = new CountDownLatch(1);
     protected final EventListener eventListener;
     protected final ReentrantLock failEngineLock = new ReentrantLock();
@@ -164,6 +184,30 @@ public final EngineConfig config() {
 
     protected abstract SegmentInfos getLastCommittedSegmentInfos();
 
+    /**
+     * Return the latest active SegmentInfos from the engine.
+     * @return {@link SegmentInfos}
+     */
+    protected SegmentInfos getLatestSegmentInfos() {
+        // Default Implementation.
+        return null;
+    };
+
+    /**
+     * In contrast to {@link #getLatestSegmentInfos()}, which returns a {@link SegmentInfos}
+     * object directly, this method returns a {@link GatedCloseable} reference to the same object.
+     * This allows the engine to include a clean-up {@link org.opensearch.common.CheckedRunnable}
+     * which is run when the reference is closed. The default implementation of the clean-up
+     * procedure is a no-op.
+     *
+     * @return {@link GatedCloseable} - A wrapper around a {@link SegmentInfos} instance that
+     * must be closed for segment files to be deleted.
+     */
+    public GatedCloseable<SegmentInfos> getSegmentInfosSnapshot() {
+        // default implementation
+        return new GatedCloseable<>(getLatestSegmentInfos(), () -> {});
+    }
+
     public MergeStats getMergeStats() {
         return new MergeStats();
     }
@@ -171,6 +215,17 @@ public MergeStats getMergeStats() {
     /** returns the history uuid for the engine */
     public abstract String getHistoryUUID();
 
+    /**
+     * Reads the current stored history ID from commit data.
+     */
+    String loadHistoryUUID(Map<String, String> commitData) {
+        final String uuid = commitData.get(HISTORY_UUID_KEY);
+        if (uuid == null) {
+            throw new IllegalStateException("commit doesn't contain history uuid");
+        }
+        return uuid;
+    }
+
     /** Returns how many bytes we are currently moving from heap to disk */
     public abstract long getWritingBytes();
 
@@ -214,6 +269,13 @@ protected final DocsStats docsStats(IndexReader indexReader) {
         return new DocsStats(numDocs, numDeletedDocs, sizeInBytes);
     }
 
+    /**
+     * Returns the unreferenced file cleanup count for this engine.
+     */
+    public long unreferencedFileCleanUpsPerformed() {
+        return totalUnreferencedFileCleanUpsPerformed.count();
+    }
+
     /**
      * Performs the pre-closing checks on the {@link Engine}.
      *
@@ -234,10 +296,48 @@ public void verifyEngineBeforeIndexClosing() throws IllegalStateException {
         }
     }
 
+    /**
+     * Get max sequence number from segments that are referenced by given SegmentInfos
+     */
+    public long getMaxSeqNoFromSegmentInfos(SegmentInfos segmentInfos) throws IOException {
+        try (DirectoryReader innerReader = StandardDirectoryReader.open(store.directory(), segmentInfos, null, null)) {
+            final IndexSearcher searcher = new IndexSearcher(innerReader);
+            return getMaxSeqNoFromSearcher(searcher);
+        }
+    }
+
+    /**
+     * Get max sequence number that is part of given searcher. Sequence number is part of each document that is indexed.
+     * This method fetches the _id of last indexed document that was part of the given searcher and
+     * retrieves the _seq_no of the retrieved document.
+     */
+    protected long getMaxSeqNoFromSearcher(IndexSearcher searcher) throws IOException {
+        searcher.setQueryCache(null);
+        ScoreDoc[] docs = searcher.search(
+            Queries.newMatchAllQuery(),
+            1,
+            new Sort(new SortField(SeqNoFieldMapper.NAME, SortField.Type.LONG, true))
+        ).scoreDocs;
+        if (docs.length == 0) {
+            return SequenceNumbers.NO_OPS_PERFORMED;
+        }
+        org.apache.lucene.document.Document document = searcher.doc(docs[0].doc);
+        Term uidTerm = new Term(IdFieldMapper.NAME, document.getField(IdFieldMapper.NAME).binaryValue());
+        VersionsAndSeqNoResolver.DocIdAndVersion docIdAndVersion = VersionsAndSeqNoResolver.loadDocIdAndVersion(
+            searcher.getIndexReader(),
+            uidTerm,
+            true
+        );
+        assert docIdAndVersion != null;
+        return docIdAndVersion.seqNo;
+    }
+
     /**
      * A throttling class that can be activated, causing the
      * {@code acquireThrottle} method to block on a lock when throttling
      * is enabled
+     *
+     * @opensearch.internal
      */
     protected static final class IndexThrottle {
         private final CounterMetric throttleTimeMillisMetric = new CounterMetric();
@@ -312,7 +412,11 @@ boolean throttleLockIsHeldByCurrentThread() { // to be used in assertions and te
      */
     public abstract void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws EngineException;
 
-    /** A Lock implementation that always allows the lock to be acquired */
+    /**
+     * A Lock implementation that always allows the lock to be acquired
+     *
+     * @opensearch.internal
+     */
     protected static final class NoOpLock implements Lock {
 
         @Override
@@ -366,6 +470,8 @@ public Condition newCondition() {
      * Base class for index and delete operation results
      * Holds result meta data (e.g. translog location, updated version)
      * for an executed write {@link Operation}
+     *
+     * @opensearch.internal
      **/
     public abstract static class Result {
         private final Operation.TYPE operationType;
@@ -479,6 +585,11 @@ void freeze() {
             freeze.set(true);
         }
 
+        /**
+         * Type of the result
+         *
+         * @opensearch.internal
+         */
         public enum Type {
             SUCCESS,
             FAILURE,
@@ -486,6 +597,11 @@ public enum Type {
         }
     }
 
+    /**
+     * Index result
+     *
+     * @opensearch.internal
+     */
     public static class IndexResult extends Result {
 
         private final boolean created;
@@ -518,6 +634,11 @@ public boolean isCreated() {
 
     }
 
+    /**
+     * The delete result
+     *
+     * @opensearch.internal
+     */
     public static class DeleteResult extends Result {
 
         private final boolean found;
@@ -550,6 +671,11 @@ public boolean isFound() {
 
     }
 
+    /**
+     * A noop result
+     *
+     * @opensearch.internal
+     */
     public static class NoOpResult extends Result {
 
         NoOpResult(long term, long seqNo) {
@@ -708,6 +834,11 @@ boolean assertSearcherIsWarmedUp(String source, SearcherScope scope) {
         return true;
     }
 
+    /**
+     * Scope of the searcher
+     *
+     * @opensearch.internal
+     */
     public enum SearcherScope {
         EXTERNAL,
         INTERNAL
@@ -742,6 +873,19 @@ public abstract Translog.Snapshot newChangesSnapshot(
         boolean accurateCount
     ) throws IOException;
 
+    /**
+     * Reads history operations from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     */
+    @Deprecated
+    public abstract Translog.Snapshot newChangesSnapshotFromTranslogFile(
+        String source,
+        long fromSeqNo,
+        long toSeqNo,
+        boolean requiredFullRange
+    ) throws IOException;
+
     /**
      * Counts the number of history operations in the given sequence number range
      * @param source       source of the request
@@ -777,7 +921,7 @@ protected final void ensureOpen(Exception suppressed) {
         }
     }
 
-    protected final void ensureOpen() {
+    public final void ensureOpen() {
         ensureOpen(null);
     }
 
@@ -828,6 +972,22 @@ public SegmentsStats segmentsStats(boolean includeSegmentFileSizes, boolean incl
         return stats;
     }
 
+    protected TranslogDeletionPolicy getTranslogDeletionPolicy(EngineConfig engineConfig) {
+        TranslogDeletionPolicy customTranslogDeletionPolicy = null;
+        if (engineConfig.getCustomTranslogDeletionPolicyFactory() != null) {
+            customTranslogDeletionPolicy = engineConfig.getCustomTranslogDeletionPolicyFactory()
+                .create(engineConfig.getIndexSettings(), engineConfig.retentionLeasesSupplier());
+        }
+        return Objects.requireNonNullElseGet(
+            customTranslogDeletionPolicy,
+            () -> new DefaultTranslogDeletionPolicy(
+                engineConfig.getIndexSettings().getTranslogRetentionSize().getBytes(),
+                engineConfig.getIndexSettings().getTranslogRetentionAge().getMillis(),
+                engineConfig.getIndexSettings().getTranslogRetentionTotalFiles()
+            )
+        );
+    }
+
     protected void fillSegmentStats(SegmentReader segmentReader, boolean includeSegmentFileSizes, SegmentsStats stats) {
         stats.add(1);
         if (includeSegmentFileSizes) {
@@ -836,7 +996,11 @@ protected void fillSegmentStats(SegmentReader segmentReader, boolean includeSegm
         }
     }
 
-    private ImmutableOpenMap<String, Long> getSegmentFileSizes(SegmentReader segmentReader) {
+    boolean shouldCleanupUnreferencedFiles() {
+        return engineConfig.getIndexSettings().shouldCleanupUnreferencedFiles();
+    }
+
+    private Map<String, Long> getSegmentFileSizes(SegmentReader segmentReader) {
         Directory directory = null;
         SegmentCommitInfo segmentCommitInfo = segmentReader.getSegmentInfo();
         boolean useCompoundFile = segmentCommitInfo.info.getUseCompoundFile();
@@ -855,7 +1019,7 @@ private ImmutableOpenMap<String, Long> getSegmentFileSizes(SegmentReader segment
                     e
                 );
 
-                return ImmutableOpenMap.of();
+                return Map.of();
             }
         } else {
             directory = segmentReader.directory();
@@ -870,7 +1034,7 @@ private ImmutableOpenMap<String, Long> getSegmentFileSizes(SegmentReader segment
             } catch (IOException e) {
                 final Directory finalDirectory = directory;
                 logger.warn(() -> new ParameterizedMessage("Couldn't list Compound Reader Directory [{}]", finalDirectory), e);
-                return ImmutableOpenMap.of();
+                return Map.of();
             }
         } else {
             try {
@@ -884,11 +1048,11 @@ private ImmutableOpenMap<String, Long> getSegmentFileSizes(SegmentReader segment
                     ),
                     e
                 );
-                return ImmutableOpenMap.of();
+                return Map.of();
             }
         }
 
-        ImmutableOpenMap.Builder<String, Long> map = ImmutableOpenMap.builder();
+        Map<String, Long> map = new HashMap<>();
         for (String file : files) {
             String extension = IndexFileNames.getExtension(file);
             long length = 0L;
@@ -919,7 +1083,7 @@ private ImmutableOpenMap<String, Long> getSegmentFileSizes(SegmentReader segment
             }
         }
 
-        return map.build();
+        return Collections.unmodifiableMap(map);
     }
 
     protected void writerSegmentStats(SegmentsStats stats) {
@@ -1196,6 +1360,14 @@ public void failEngine(String reason, @Nullable Exception failure) {
                             );
                         }
                     }
+
+                    // If cleanup of unreferenced flag is enabled and force merge or regular merge failed due to IOException,
+                    // clean all unreferenced files on best effort basis created during failed merge and reset the
+                    // shard state back to last Lucene Commit.
+                    if (shouldCleanupUnreferencedFiles() && isMergeFailureDueToIOException(failure, reason)) {
+                        cleanUpUnreferencedFiles();
+                    }
+
                     eventListener.onFailedEngine(reason, failure);
                 }
             } catch (Exception inner) {
@@ -1214,6 +1386,34 @@ public void failEngine(String reason, @Nullable Exception failure) {
         }
     }
 
+    /**
+     * Cleanup all unreferenced files generated during failed segment merge. This resets shard state to last Lucene
+     * commit.
+     */
+    private void cleanUpUnreferencedFiles() {
+        try (
+            IndexWriter writer = new IndexWriter(
+                store.directory(),
+                new IndexWriterConfig(Lucene.STANDARD_ANALYZER).setSoftDeletesField(Lucene.SOFT_DELETES_FIELD)
+                    .setCommitOnClose(false)
+                    .setMergePolicy(NoMergePolicy.INSTANCE)
+                    .setOpenMode(IndexWriterConfig.OpenMode.APPEND)
+            )
+        ) {
+            // do nothing except increasing metric count and close this will kick off IndexFileDeleter which will
+            // remove all unreferenced files
+            totalUnreferencedFileCleanUpsPerformed.inc();
+        } catch (Exception ex) {
+            logger.error("Error while deleting unreferenced file ", ex);
+        }
+    }
+
+    /** Check whether the merge failure happened due to IOException. */
+    private boolean isMergeFailureDueToIOException(Exception failure, String reason) {
+        return (reason.equals(FORCE_MERGE) || reason.equals(MERGE_FAILED))
+            && ExceptionsHelper.unwrap(failure, IOException.class) instanceof IOException;
+    }
+
     /** Check whether the engine should be failed */
     protected boolean maybeFailEngine(String source, Exception e) {
         if (Lucene.isCorruptionException(e)) {
@@ -1223,6 +1423,11 @@ protected boolean maybeFailEngine(String source, Exception e) {
         return false;
     }
 
+    /**
+     * Event listener for the engine
+     *
+     * @opensearch.internal
+     */
     public interface EventListener {
         /**
          * Called when a fatal exception occurred
@@ -1230,6 +1435,11 @@ public interface EventListener {
         default void onFailedEngine(String reason, @Nullable Exception e) {}
     }
 
+    /**
+     * Supplier for the searcher
+     *
+     * @opensearch.internal
+     */
     public abstract static class SearcherSupplier implements Releasable {
         private final Function<Searcher, Searcher> wrapper;
         private final AtomicBoolean released = new AtomicBoolean(false);
@@ -1260,6 +1470,11 @@ public final void close() {
         protected abstract Searcher acquireSearcherInternal(String source);
     }
 
+    /**
+     * The engine searcher
+     *
+     * @opensearch.internal
+     */
     public static final class Searcher extends IndexSearcher implements Releasable {
         private final String source;
         private final Closeable onClose;
@@ -1307,9 +1522,18 @@ public void close() {
         }
     }
 
+    /**
+     * Base operation class
+     *
+     * @opensearch.internal
+     */
     public abstract static class Operation {
 
-        /** type of operation (index, delete), subclasses use static types */
+        /**
+         * type of operation (index, delete), subclasses use static types
+         *
+         * @opensearch.internal
+         */
         public enum TYPE {
             INDEX,
             DELETE,
@@ -1344,6 +1568,11 @@ public Operation(Term uid, long seqNo, long primaryTerm, long version, VersionTy
             this.startTime = startTime;
         }
 
+        /**
+         * Origin of the operation
+         *
+         * @opensearch.internal
+         */
         public enum Origin {
             PRIMARY,
             REPLICA,
@@ -1398,6 +1627,11 @@ public long startTime() {
         public abstract TYPE operationType();
     }
 
+    /**
+     * Index operation
+     *
+     * @opensearch.internal
+     */
     public static class Index extends Operation {
 
         private final ParsedDocument doc;
@@ -1511,6 +1745,11 @@ public long getIfPrimaryTerm() {
         }
     }
 
+    /**
+     * Delete operation
+     *
+     * @opensearch.internal
+     */
     public static class Delete extends Operation {
 
         private final String id;
@@ -1594,6 +1833,11 @@ public long getIfPrimaryTerm() {
         }
     }
 
+    /**
+     * noop operation
+     *
+     * @opensearch.internal
+     */
     public static class NoOp extends Operation {
 
         private final String reason;
@@ -1639,6 +1883,11 @@ public int estimatedSizeInBytes() {
 
     }
 
+    /**
+     * Get operation
+     *
+     * @opensearch.internal
+     */
     public static class Get {
         private final boolean realtime;
         private final Term uid;
@@ -1710,6 +1959,11 @@ public long getIfPrimaryTerm() {
 
     }
 
+    /**
+     * The Get result
+     *
+     * @opensearch.internal
+     */
     public static class GetResult implements Releasable {
         private final boolean exists;
         private final long version;
@@ -1830,6 +2084,8 @@ public long getLastWriteNanos() {
      * Called for each new opened engine reader to warm new segments
      *
      * @see EngineConfig#getWarmer()
+     *
+     * @opensearch.internal
      */
     public interface Warmer {
         /**
@@ -1899,6 +2155,11 @@ public long getMaxSeenAutoIdTimestamp() {
      */
     public abstract void updateMaxUnsafeAutoIdTimestamp(long newTimestamp);
 
+    /**
+     * The runner for translog recovery
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface TranslogRecoveryRunner {
         int run(Engine engine, Translog.Snapshot snapshot) throws IOException;
@@ -1945,4 +2206,5 @@ public interface TranslogRecoveryRunner {
      * to advance this marker to at least the given sequence number.
      */
     public abstract void advanceMaxSeqNoOfUpdatesOrDeletes(long maxSeqNoOfUpdatesOnPrimary);
+
 }
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
index d1085b01a3707..00f8ff6d3cd40 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineConfig.java
@@ -33,6 +33,7 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.MergePolicy;
 import org.apache.lucene.search.QueryCache;
 import org.apache.lucene.search.QueryCachingPolicy;
@@ -42,30 +43,39 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.MemorySizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.codec.CodecAliases;
 import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.codec.CodecSettings;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.InternalTranslogFactory;
 import org.opensearch.index.translog.TranslogConfig;
 import org.opensearch.index.translog.TranslogDeletionPolicyFactory;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.indices.IndexingMemoryController;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.threadpool.ThreadPool;
 
+import java.util.Comparator;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
+import java.util.function.BooleanSupplier;
 import java.util.function.LongSupplier;
 import java.util.function.Supplier;
 
-/*
+/**
  * Holds all the configuration that is used to create an {@link Engine}.
  * Once {@link Engine} has been created with this object, changes to this
  * object will affect the {@link Engine} instance.
+ *
+ * @opensearch.internal
  */
 public final class EngineConfig {
     private final ShardId shardId;
@@ -95,6 +105,9 @@ public final class EngineConfig {
     private final CircuitBreakerService circuitBreakerService;
     private final LongSupplier globalCheckpointSupplier;
     private final Supplier<RetentionLeases> retentionLeasesSupplier;
+    private final boolean isReadOnlyReplica;
+    private final BooleanSupplier primaryModeSupplier;
+    private final Comparator<LeafReader> leafSorter;
 
     /**
      * A supplier of the outstanding retention leases. This is used during merged operations to determine which operations that have been
@@ -118,19 +131,95 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
     public static final Setting<String> INDEX_CODEC_SETTING = new Setting<>("index.codec", "default", s -> {
         switch (s) {
             case "default":
+            case "lz4":
             case "best_compression":
+            case "zlib":
             case "lucene_default":
                 return s;
             default:
-                if (Codec.availableCodecs().contains(s) == false) { // we don't error message the not officially supported ones
-                    throw new IllegalArgumentException(
-                        "unknown value for [index.codec] must be one of [default, best_compression] but was: " + s
-                    );
+                if (Codec.availableCodecs().contains(s)) {
+                    return s;
                 }
-                return s;
+
+                for (String codecName : Codec.availableCodecs()) {
+                    Codec codec = Codec.forName(codecName);
+                    if (codec instanceof CodecAliases) {
+                        CodecAliases codecWithAlias = (CodecAliases) codec;
+                        if (codecWithAlias.aliases().contains(s)) {
+                            return s;
+                        }
+                    }
+                }
+
+                throw new IllegalArgumentException(
+                    "unknown value for [index.codec] must be one of [default, lz4, best_compression, zlib] but was: " + s
+                );
         }
     }, Property.IndexScope, Property.NodeScope);
 
+    /**
+     * Index setting to change the compression level of zstd and zstd_no_dict lucene codecs.
+     * Compression Level gives a trade-off between compression ratio and speed. The higher compression level results in higher compression ratio but slower compression and decompression speeds.
+     * This setting is <b>not</b> realtime updateable.
+     */
+
+    public static final Setting<Integer> INDEX_CODEC_COMPRESSION_LEVEL_SETTING = new Setting<>(
+        "index.codec.compression_level",
+        Integer.toString(3),
+        new Setting.IntegerParser(1, 6, "index.codec.compression_level", false),
+        Property.IndexScope
+    ) {
+        @Override
+        public Set<SettingDependency> getSettingsDependencies(String key) {
+            return Set.of(new SettingDependency() {
+                @Override
+                public Setting<String> getSetting() {
+                    return INDEX_CODEC_SETTING;
+                }
+
+                @Override
+                public void validate(String key, Object value, Object dependency) {
+                    if (!(dependency instanceof String)) {
+                        throw new IllegalArgumentException("Codec should be of string type.");
+                    }
+                    doValidateCodecSettings((String) dependency);
+                }
+            });
+        }
+    };
+
+    private static void doValidateCodecSettings(final String codec) {
+        switch (codec) {
+            case "best_compression":
+            case "zlib":
+            case "lucene_default":
+            case "default":
+            case "lz4":
+                break;
+            default:
+                if (Codec.availableCodecs().contains(codec)) {
+                    Codec luceneCodec = Codec.forName(codec);
+                    if (luceneCodec instanceof CodecSettings
+                        && ((CodecSettings) luceneCodec).supports(INDEX_CODEC_COMPRESSION_LEVEL_SETTING)) {
+                        return;
+                    }
+                }
+                for (String codecName : Codec.availableCodecs()) {
+                    Codec availableCodec = Codec.forName(codecName);
+                    if (availableCodec instanceof CodecAliases) {
+                        CodecAliases availableCodecWithAlias = (CodecAliases) availableCodec;
+                        if (availableCodecWithAlias.aliases().contains(codec)) {
+                            if (availableCodec instanceof CodecSettings
+                                && ((CodecSettings) availableCodec).supports(INDEX_CODEC_COMPRESSION_LEVEL_SETTING)) {
+                                return;
+                            }
+                        }
+                    }
+                }
+        }
+        throw new IllegalArgumentException("Compression level cannot be set for the " + codec + " codec.");
+    }
+
     /**
      * Configures an index to optimize documents with auto generated ids for append only. If this setting is updated from <code>false</code>
      * to <code>true</code> might not take effect immediately. In other words, disabling the optimization will be immediately applied while
@@ -147,96 +236,27 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
 
     private final TranslogConfig translogConfig;
 
-    public EngineConfig(
-        ShardId shardId,
-        ThreadPool threadPool,
-        IndexSettings indexSettings,
-        Engine.Warmer warmer,
-        Store store,
-        MergePolicy mergePolicy,
-        Analyzer analyzer,
-        Similarity similarity,
-        CodecService codecService,
-        Engine.EventListener eventListener,
-        QueryCache queryCache,
-        QueryCachingPolicy queryCachingPolicy,
-        TranslogConfig translogConfig,
-        TimeValue flushMergesAfter,
-        List<ReferenceManager.RefreshListener> externalRefreshListener,
-        List<ReferenceManager.RefreshListener> internalRefreshListener,
-        Sort indexSort,
-        CircuitBreakerService circuitBreakerService,
-        LongSupplier globalCheckpointSupplier,
-        Supplier<RetentionLeases> retentionLeasesSupplier,
-        LongSupplier primaryTermSupplier,
-        TombstoneDocSupplier tombstoneDocSupplier
-    ) {
-        this(
-            shardId,
-            threadPool,
-            indexSettings,
-            warmer,
-            store,
-            mergePolicy,
-            analyzer,
-            similarity,
-            codecService,
-            eventListener,
-            queryCache,
-            queryCachingPolicy,
-            translogConfig,
-            null,
-            flushMergesAfter,
-            externalRefreshListener,
-            internalRefreshListener,
-            indexSort,
-            circuitBreakerService,
-            globalCheckpointSupplier,
-            retentionLeasesSupplier,
-            primaryTermSupplier,
-            tombstoneDocSupplier
-        );
-    }
+    private final TranslogFactory translogFactory;
 
     /**
      * Creates a new {@link org.opensearch.index.engine.EngineConfig}
      */
-    EngineConfig(
-        ShardId shardId,
-        ThreadPool threadPool,
-        IndexSettings indexSettings,
-        Engine.Warmer warmer,
-        Store store,
-        MergePolicy mergePolicy,
-        Analyzer analyzer,
-        Similarity similarity,
-        CodecService codecService,
-        Engine.EventListener eventListener,
-        QueryCache queryCache,
-        QueryCachingPolicy queryCachingPolicy,
-        TranslogConfig translogConfig,
-        TranslogDeletionPolicyFactory translogDeletionPolicyFactory,
-        TimeValue flushMergesAfter,
-        List<ReferenceManager.RefreshListener> externalRefreshListener,
-        List<ReferenceManager.RefreshListener> internalRefreshListener,
-        Sort indexSort,
-        CircuitBreakerService circuitBreakerService,
-        LongSupplier globalCheckpointSupplier,
-        Supplier<RetentionLeases> retentionLeasesSupplier,
-        LongSupplier primaryTermSupplier,
-        TombstoneDocSupplier tombstoneDocSupplier
-    ) {
-        this.shardId = shardId;
-        this.indexSettings = indexSettings;
-        this.threadPool = threadPool;
-        this.warmer = warmer == null ? (a) -> {} : warmer;
-        this.store = store;
-        this.mergePolicy = mergePolicy;
-        this.analyzer = analyzer;
-        this.similarity = similarity;
-        this.codecService = codecService;
-        this.eventListener = eventListener;
-        codecName = indexSettings.getValue(INDEX_CODEC_SETTING);
+    private EngineConfig(Builder builder) {
+        if (builder.isReadOnlyReplica && builder.indexSettings.isSegRepEnabled() == false) {
+            throw new IllegalArgumentException("Shard can only be wired as a read only replica with Segment Replication enabled");
+        }
+        this.shardId = builder.shardId;
+        this.indexSettings = builder.indexSettings;
+        this.threadPool = builder.threadPool;
+        this.warmer = builder.warmer == null ? (a) -> {} : builder.warmer;
+        this.store = builder.store;
+        this.mergePolicy = builder.mergePolicy;
+        this.analyzer = builder.analyzer;
+        this.similarity = builder.similarity;
+        this.codecService = builder.codecService;
+        this.eventListener = builder.eventListener;
+        codecName = builder.indexSettings.getValue(INDEX_CODEC_SETTING);
+
         // We need to make the indexing buffer for this shard at least as large
         // as the amount of memory that is available for all engines on the
         // local node so that decisions to flush segments to disk are made by
@@ -249,21 +269,25 @@ public EngineConfig(
         if (maxBufferSize != null) {
             indexingBufferSize = MemorySizeValue.parseBytesSizeValueOrHeapRatio(maxBufferSize, escapeHatchProperty);
         } else {
-            indexingBufferSize = IndexingMemoryController.INDEX_BUFFER_SIZE_SETTING.get(indexSettings.getNodeSettings());
+            indexingBufferSize = IndexingMemoryController.INDEX_BUFFER_SIZE_SETTING.get(builder.indexSettings.getNodeSettings());
         }
-        this.queryCache = queryCache;
-        this.queryCachingPolicy = queryCachingPolicy;
-        this.translogConfig = translogConfig;
-        this.translogDeletionPolicyFactory = translogDeletionPolicyFactory;
-        this.flushMergesAfter = flushMergesAfter;
-        this.externalRefreshListener = externalRefreshListener;
-        this.internalRefreshListener = internalRefreshListener;
-        this.indexSort = indexSort;
-        this.circuitBreakerService = circuitBreakerService;
-        this.globalCheckpointSupplier = globalCheckpointSupplier;
-        this.retentionLeasesSupplier = Objects.requireNonNull(retentionLeasesSupplier);
-        this.primaryTermSupplier = primaryTermSupplier;
-        this.tombstoneDocSupplier = tombstoneDocSupplier;
+        this.queryCache = builder.queryCache;
+        this.queryCachingPolicy = builder.queryCachingPolicy;
+        this.translogConfig = builder.translogConfig;
+        this.translogDeletionPolicyFactory = builder.translogDeletionPolicyFactory;
+        this.flushMergesAfter = builder.flushMergesAfter;
+        this.externalRefreshListener = builder.externalRefreshListener;
+        this.internalRefreshListener = builder.internalRefreshListener;
+        this.indexSort = builder.indexSort;
+        this.circuitBreakerService = builder.circuitBreakerService;
+        this.globalCheckpointSupplier = builder.globalCheckpointSupplier;
+        this.retentionLeasesSupplier = Objects.requireNonNull(builder.retentionLeasesSupplier);
+        this.primaryTermSupplier = builder.primaryTermSupplier;
+        this.tombstoneDocSupplier = builder.tombstoneDocSupplier;
+        this.isReadOnlyReplica = builder.isReadOnlyReplica;
+        this.primaryModeSupplier = builder.primaryModeSupplier;
+        this.translogFactory = builder.translogFactory;
+        this.leafSorter = builder.leafSorter;
     }
 
     /**
@@ -458,9 +482,37 @@ public LongSupplier getPrimaryTermSupplier() {
         return primaryTermSupplier;
     }
 
+    /**
+     * Returns if this replica should be wired as a read only.
+     * This is used for Segment Replication where the engine implementation used is dependent on
+     * if the shard is a primary/replica.
+     * @return true if this engine should be wired as read only.
+     */
+    public boolean isReadOnlyReplica() {
+        return indexSettings.isSegRepEnabled() && isReadOnlyReplica;
+    }
+
+    /**
+     * Returns the underlying primaryModeSupplier.
+     * @return the primary mode supplier.
+     */
+    public BooleanSupplier getPrimaryModeSupplier() {
+        return primaryModeSupplier;
+    }
+
+    /**
+     * Returns the underlying translog factory
+     * @return the translog factory
+     */
+    public TranslogFactory getTranslogFactory() {
+        return translogFactory;
+    }
+
     /**
      * A supplier supplies tombstone documents which will be used in soft-update methods.
      * The returned document consists only _uid, _seqno, _term and _version fields; other metadata fields are excluded.
+     *
+     * @opensearch.internal
      */
     public interface TombstoneDocSupplier {
         /**
@@ -482,4 +534,187 @@ public TombstoneDocSupplier getTombstoneDocSupplier() {
     public TranslogDeletionPolicyFactory getCustomTranslogDeletionPolicyFactory() {
         return translogDeletionPolicyFactory;
     }
+
+    /**
+     * Returns subReaderSorter for org.apache.lucene.index.BaseCompositeReader.
+     * This gets used in lucene IndexReader and decides order of segment read.
+     * @return comparator
+     */
+    public Comparator<LeafReader> getLeafSorter() {
+        return this.leafSorter;
+    }
+
+    /**
+     * Builder for EngineConfig class
+     *
+     * @opensearch.internal
+     */
+    public static class Builder {
+        private ShardId shardId;
+        private ThreadPool threadPool;
+        private IndexSettings indexSettings;
+        private Engine.Warmer warmer;
+        private Store store;
+        private MergePolicy mergePolicy;
+        private Analyzer analyzer;
+        private Similarity similarity;
+        private CodecService codecService;
+        private Engine.EventListener eventListener;
+        private QueryCache queryCache;
+        private QueryCachingPolicy queryCachingPolicy;
+        private TranslogConfig translogConfig;
+        private TimeValue flushMergesAfter;
+        private List<ReferenceManager.RefreshListener> externalRefreshListener;
+        private List<ReferenceManager.RefreshListener> internalRefreshListener;
+        private Sort indexSort;
+        private CircuitBreakerService circuitBreakerService;
+        private LongSupplier globalCheckpointSupplier;
+        private Supplier<RetentionLeases> retentionLeasesSupplier;
+        private LongSupplier primaryTermSupplier;
+        private TombstoneDocSupplier tombstoneDocSupplier;
+        private TranslogDeletionPolicyFactory translogDeletionPolicyFactory;
+        private boolean isReadOnlyReplica;
+        private BooleanSupplier primaryModeSupplier;
+        private TranslogFactory translogFactory = new InternalTranslogFactory();
+        Comparator<LeafReader> leafSorter;
+
+        public Builder shardId(ShardId shardId) {
+            this.shardId = shardId;
+            return this;
+        }
+
+        public Builder threadPool(ThreadPool threadPool) {
+            this.threadPool = threadPool;
+            return this;
+        }
+
+        public Builder indexSettings(IndexSettings indexSettings) {
+            this.indexSettings = indexSettings;
+            return this;
+        }
+
+        public Builder warmer(Engine.Warmer warmer) {
+            this.warmer = warmer;
+            return this;
+        }
+
+        public Builder store(Store store) {
+            this.store = store;
+            return this;
+        }
+
+        public Builder mergePolicy(MergePolicy mergePolicy) {
+            this.mergePolicy = mergePolicy;
+            return this;
+        }
+
+        public Builder analyzer(Analyzer analyzer) {
+            this.analyzer = analyzer;
+            return this;
+        }
+
+        public Builder similarity(Similarity similarity) {
+            this.similarity = similarity;
+            return this;
+        }
+
+        public Builder codecService(CodecService codecService) {
+            this.codecService = codecService;
+            return this;
+        }
+
+        public Builder eventListener(Engine.EventListener eventListener) {
+            this.eventListener = eventListener;
+            return this;
+        }
+
+        public Builder queryCache(QueryCache queryCache) {
+            this.queryCache = queryCache;
+            return this;
+        }
+
+        public Builder queryCachingPolicy(QueryCachingPolicy queryCachingPolicy) {
+            this.queryCachingPolicy = queryCachingPolicy;
+            return this;
+        }
+
+        public Builder translogConfig(TranslogConfig translogConfig) {
+            this.translogConfig = translogConfig;
+            return this;
+        }
+
+        public Builder flushMergesAfter(TimeValue flushMergesAfter) {
+            this.flushMergesAfter = flushMergesAfter;
+            return this;
+        }
+
+        public Builder externalRefreshListener(List<ReferenceManager.RefreshListener> externalRefreshListener) {
+            this.externalRefreshListener = externalRefreshListener;
+            return this;
+        }
+
+        public Builder internalRefreshListener(List<ReferenceManager.RefreshListener> internalRefreshListener) {
+            this.internalRefreshListener = internalRefreshListener;
+            return this;
+        }
+
+        public Builder indexSort(Sort indexSort) {
+            this.indexSort = indexSort;
+            return this;
+        }
+
+        public Builder circuitBreakerService(CircuitBreakerService circuitBreakerService) {
+            this.circuitBreakerService = circuitBreakerService;
+            return this;
+        }
+
+        public Builder globalCheckpointSupplier(LongSupplier globalCheckpointSupplier) {
+            this.globalCheckpointSupplier = globalCheckpointSupplier;
+            return this;
+        }
+
+        public Builder retentionLeasesSupplier(Supplier<RetentionLeases> retentionLeasesSupplier) {
+            this.retentionLeasesSupplier = retentionLeasesSupplier;
+            return this;
+        }
+
+        public Builder primaryTermSupplier(LongSupplier primaryTermSupplier) {
+            this.primaryTermSupplier = primaryTermSupplier;
+            return this;
+        }
+
+        public Builder tombstoneDocSupplier(TombstoneDocSupplier tombstoneDocSupplier) {
+            this.tombstoneDocSupplier = tombstoneDocSupplier;
+            return this;
+        }
+
+        public Builder translogDeletionPolicyFactory(TranslogDeletionPolicyFactory translogDeletionPolicyFactory) {
+            this.translogDeletionPolicyFactory = translogDeletionPolicyFactory;
+            return this;
+        }
+
+        public Builder readOnlyReplica(boolean isReadOnlyReplica) {
+            this.isReadOnlyReplica = isReadOnlyReplica;
+            return this;
+        }
+
+        public Builder primaryModeSupplier(BooleanSupplier primaryModeSupplier) {
+            this.primaryModeSupplier = primaryModeSupplier;
+            return this;
+        }
+
+        public Builder translogFactory(TranslogFactory translogFactory) {
+            this.translogFactory = translogFactory;
+            return this;
+        }
+
+        public Builder leafSorter(Comparator<LeafReader> leafSorter) {
+            this.leafSorter = leafSorter;
+            return this;
+        }
+
+        public EngineConfig build() {
+            return new EngineConfig(this);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineConfigFactory.java b/server/src/main/java/org/opensearch/index/engine/EngineConfigFactory.java
index a78a5e5a4820a..38eea92b6c757 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineConfigFactory.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineConfigFactory.java
@@ -10,6 +10,7 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.MergePolicy;
 import org.apache.lucene.search.QueryCache;
 import org.apache.lucene.search.QueryCachingPolicy;
@@ -18,30 +19,35 @@
 import org.apache.lucene.search.similarities.Similarity;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.codec.CodecService;
 import org.opensearch.index.codec.CodecServiceConfig;
 import org.opensearch.index.codec.CodecServiceFactory;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.TranslogConfig;
 import org.opensearch.index.translog.TranslogDeletionPolicyFactory;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.plugins.EnginePlugin;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
+import java.util.function.BooleanSupplier;
 import java.util.function.LongSupplier;
 import java.util.function.Supplier;
 
 /**
  * A factory to create an EngineConfig based on custom plugin overrides
+ *
+ * @opensearch.internal
  */
 public class EngineConfigFactory {
     private final CodecServiceFactory codecServiceFactory;
@@ -144,38 +150,45 @@ public EngineConfig newEngineConfig(
         LongSupplier globalCheckpointSupplier,
         Supplier<RetentionLeases> retentionLeasesSupplier,
         LongSupplier primaryTermSupplier,
-        EngineConfig.TombstoneDocSupplier tombstoneDocSupplier
+        EngineConfig.TombstoneDocSupplier tombstoneDocSupplier,
+        boolean isReadOnlyReplica,
+        BooleanSupplier primaryModeSupplier,
+        TranslogFactory translogFactory,
+        Comparator<LeafReader> leafSorter
     ) {
         CodecService codecServiceToUse = codecService;
         if (codecService == null && this.codecServiceFactory != null) {
             codecServiceToUse = newCodecServiceOrDefault(indexSettings, null, null, null);
         }
 
-        return new EngineConfig(
-            shardId,
-            threadPool,
-            indexSettings,
-            warmer,
-            store,
-            mergePolicy,
-            analyzer,
-            similarity,
-            codecServiceToUse,
-            eventListener,
-            queryCache,
-            queryCachingPolicy,
-            translogConfig,
-            translogDeletionPolicyFactory,
-            flushMergesAfter,
-            externalRefreshListener,
-            internalRefreshListener,
-            indexSort,
-            circuitBreakerService,
-            globalCheckpointSupplier,
-            retentionLeasesSupplier,
-            primaryTermSupplier,
-            tombstoneDocSupplier
-        );
+        return new EngineConfig.Builder().shardId(shardId)
+            .threadPool(threadPool)
+            .indexSettings(indexSettings)
+            .warmer(warmer)
+            .store(store)
+            .mergePolicy(mergePolicy)
+            .analyzer(analyzer)
+            .similarity(similarity)
+            .codecService(codecServiceToUse)
+            .eventListener(eventListener)
+            .queryCache(queryCache)
+            .queryCachingPolicy(queryCachingPolicy)
+            .translogConfig(translogConfig)
+            .translogDeletionPolicyFactory(translogDeletionPolicyFactory)
+            .flushMergesAfter(flushMergesAfter)
+            .externalRefreshListener(externalRefreshListener)
+            .internalRefreshListener(internalRefreshListener)
+            .indexSort(indexSort)
+            .circuitBreakerService(circuitBreakerService)
+            .globalCheckpointSupplier(globalCheckpointSupplier)
+            .retentionLeasesSupplier(retentionLeasesSupplier)
+            .primaryTermSupplier(primaryTermSupplier)
+            .tombstoneDocSupplier(tombstoneDocSupplier)
+            .readOnlyReplica(isReadOnlyReplica)
+            .primaryModeSupplier(primaryModeSupplier)
+            .translogFactory(translogFactory)
+            .leafSorter(leafSorter)
+            .build();
     }
 
     public CodecService newCodecServiceOrDefault(
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineCreationFailureException.java b/server/src/main/java/org/opensearch/index/engine/EngineCreationFailureException.java
index f228694cae7d4..e01b2c3e21e7e 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineCreationFailureException.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineCreationFailureException.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * An exception indicating that an {@link Engine} creation failed.
  *
- *
+ * @opensearch.internal
  */
 public class EngineCreationFailureException extends EngineException {
 
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineException.java b/server/src/main/java/org/opensearch/index/engine/EngineException.java
index bda9b433e5f40..484bc6c7eea6a 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineException.java
@@ -33,11 +33,16 @@
 package org.opensearch.index.engine;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception if there are any errors in the engine
+ *
+ * @opensearch.internal
+ */
 public class EngineException extends OpenSearchException {
 
     public EngineException(ShardId shardId, String msg, Object... params) {
diff --git a/server/src/main/java/org/opensearch/index/engine/EngineFactory.java b/server/src/main/java/org/opensearch/index/engine/EngineFactory.java
index f38e5242e2f9c..ced02ab3041c9 100644
--- a/server/src/main/java/org/opensearch/index/engine/EngineFactory.java
+++ b/server/src/main/java/org/opensearch/index/engine/EngineFactory.java
@@ -33,6 +33,8 @@
 
 /**
  * Simple Engine Factory
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface EngineFactory {
diff --git a/server/src/main/java/org/opensearch/index/engine/FlushFailedEngineException.java b/server/src/main/java/org/opensearch/index/engine/FlushFailedEngineException.java
index 711fe50f3faee..9f3bad250a984 100644
--- a/server/src/main/java/org/opensearch/index/engine/FlushFailedEngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/FlushFailedEngineException.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is an error on flush
+ *
+ * @opensearch.internal
+ */
 public class FlushFailedEngineException extends EngineException {
 
     public FlushFailedEngineException(ShardId shardId, Throwable t) {
diff --git a/server/src/main/java/org/opensearch/index/engine/IndexVersionValue.java b/server/src/main/java/org/opensearch/index/engine/IndexVersionValue.java
index 1b10385929380..803d106a2f25e 100644
--- a/server/src/main/java/org/opensearch/index/engine/IndexVersionValue.java
+++ b/server/src/main/java/org/opensearch/index/engine/IndexVersionValue.java
@@ -37,6 +37,11 @@
 
 import java.util.Objects;
 
+/**
+ * Encapsulates an Index Version in the translog
+ *
+ * @opensearch.internal
+ */
 final class IndexVersionValue extends VersionValue {
 
     private static final long RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(IndexVersionValue.class);
diff --git a/server/src/main/java/org/opensearch/index/engine/InternalEngine.java b/server/src/main/java/org/opensearch/index/engine/InternalEngine.java
index 84090047d68e8..a401d27318fb8 100644
--- a/server/src/main/java/org/opensearch/index/engine/InternalEngine.java
+++ b/server/src/main/java/org/opensearch/index/engine/InternalEngine.java
@@ -49,6 +49,8 @@
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.ShuffleForcedMergePolicy;
 import org.apache.lucene.index.SoftDeletesRetentionMergePolicy;
+import org.apache.lucene.index.StandardDirectoryReader;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
@@ -65,7 +67,6 @@
 import org.apache.lucene.store.LockObtainFailedException;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.InfoStream;
-import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.common.Booleans;
@@ -81,12 +82,14 @@
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver;
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndSeqNo;
 import org.opensearch.common.metrics.CounterMetric;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.KeyedLock;
 import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.fieldvisitor.IdOnlyFieldVisitor;
@@ -102,13 +105,14 @@
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.OpenSearchMergePolicy;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
+import org.opensearch.index.translog.InternalTranslogManager;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.index.translog.TranslogConfig;
 import org.opensearch.index.translog.TranslogCorruptedException;
 import org.opensearch.index.translog.TranslogDeletionPolicy;
+import org.opensearch.index.translog.TranslogException;
 import org.opensearch.index.translog.TranslogStats;
+import org.opensearch.index.translog.listener.CompositeTranslogEventListener;
+import org.opensearch.index.translog.listener.TranslogEventListener;
 import org.opensearch.search.suggest.completion.CompletionStats;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -130,11 +134,15 @@
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
-import java.util.function.LongConsumer;
-import java.util.function.LongSupplier;
+import java.util.function.UnaryOperator;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+/**
+ * The default internal engine (can be overridden by plugins)
+ *
+ * @opensearch.internal
+ */
 public class InternalEngine extends Engine {
 
     /**
@@ -142,7 +150,7 @@ public class InternalEngine extends Engine {
      */
     private volatile long lastDeleteVersionPruneTimeMSec;
 
-    private final Translog translog;
+    private final InternalTranslogManager translogManager;
     private final OpenSearchConcurrentMergeScheduler mergeScheduler;
 
     private final IndexWriter indexWriter;
@@ -169,7 +177,6 @@ public class InternalEngine extends Engine {
     // are falling behind and when writing indexing buffer to disk is too slow. When this is 0, there is no throttling, else we throttling
     // incoming indexing ops to a single thread:
     private final AtomicInteger throttleRequestCount = new AtomicInteger();
-    private final AtomicBoolean pendingTranslogRecovery = new AtomicBoolean(false);
     private final AtomicLong maxUnsafeAutoIdTimestamp = new AtomicLong(-1);
     private final AtomicLong maxSeenAutoIdTimestamp = new AtomicLong(-1);
     // max_seq_no_of_updates_or_deletes tracks the max seq_no of update or delete operations that have been processed in this engine.
@@ -214,36 +221,35 @@ public class InternalEngine extends Engine {
     private volatile String forceMergeUUID;
 
     public InternalEngine(EngineConfig engineConfig) {
-        this(engineConfig, IndexWriter.MAX_DOCS, LocalCheckpointTracker::new);
+        this(engineConfig, IndexWriter.MAX_DOCS, LocalCheckpointTracker::new, TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER);
+    }
+
+    public InternalEngine(EngineConfig engineConfig, TranslogEventListener translogEventListener) {
+        this(engineConfig, IndexWriter.MAX_DOCS, LocalCheckpointTracker::new, translogEventListener);
     }
 
-    InternalEngine(EngineConfig engineConfig, int maxDocs, BiFunction<Long, Long, LocalCheckpointTracker> localCheckpointTrackerSupplier) {
+    public InternalTranslogManager translogManager() {
+        return translogManager;
+    }
+
+    InternalEngine(
+        EngineConfig engineConfig,
+        int maxDocs,
+        BiFunction<Long, Long, LocalCheckpointTracker> localCheckpointTrackerSupplier,
+        TranslogEventListener translogEventListener
+    ) {
         super(engineConfig);
         this.maxDocs = maxDocs;
         if (engineConfig.isAutoGeneratedIDsOptimizationEnabled() == false) {
             updateAutoIdTimestamp(Long.MAX_VALUE, true);
         }
-        final TranslogDeletionPolicy translogDeletionPolicy;
-        TranslogDeletionPolicy customTranslogDeletionPolicy = null;
-        if (engineConfig.getCustomTranslogDeletionPolicyFactory() != null) {
-            customTranslogDeletionPolicy = engineConfig.getCustomTranslogDeletionPolicyFactory()
-                .create(engineConfig.getIndexSettings(), engineConfig.retentionLeasesSupplier());
-        }
-        if (customTranslogDeletionPolicy != null) {
-            translogDeletionPolicy = customTranslogDeletionPolicy;
-        } else {
-            translogDeletionPolicy = new DefaultTranslogDeletionPolicy(
-                engineConfig.getIndexSettings().getTranslogRetentionSize().getBytes(),
-                engineConfig.getIndexSettings().getTranslogRetentionAge().getMillis(),
-                engineConfig.getIndexSettings().getTranslogRetentionTotalFiles()
-            );
-        }
+        final TranslogDeletionPolicy translogDeletionPolicy = getTranslogDeletionPolicy(engineConfig);
         store.incRef();
         IndexWriter writer = null;
-        Translog translog = null;
         ExternalReaderManager externalReaderManager = null;
         OpenSearchReaderManager internalReaderManager = null;
         EngineMergeScheduler scheduler = null;
+        InternalTranslogManager translogManagerRef = null;
         boolean success = false;
         try {
             this.lastDeleteVersionPruneTimeMSec = engineConfig.getThreadPool().relativeTimeInMillis();
@@ -251,21 +257,50 @@ public InternalEngine(EngineConfig engineConfig) {
             throttle = new IndexThrottle();
             try {
                 store.trimUnsafeCommits(engineConfig.getTranslogConfig().getTranslogPath());
-                translog = openTranslog(engineConfig, translogDeletionPolicy, engineConfig.getGlobalCheckpointSupplier(), seqNo -> {
-                    final LocalCheckpointTracker tracker = getLocalCheckpointTracker();
-                    assert tracker != null || getTranslog().isOpen() == false;
-                    if (tracker != null) {
-                        tracker.markSeqNoAsPersisted(seqNo);
+                final Map<String, String> userData = store.readLastCommittedSegmentsInfo().getUserData();
+                final String translogUUID = Objects.requireNonNull(userData.get(Translog.TRANSLOG_UUID_KEY));
+                TranslogEventListener internalTranslogEventListener = new TranslogEventListener() {
+                    @Override
+                    public void onAfterTranslogSync() {
+                        revisitIndexDeletionPolicyOnTranslogSynced();
                     }
-                });
-                assert translog.getGeneration() != null;
-                this.translog = translog;
+
+                    @Override
+                    public void onAfterTranslogRecovery() {
+                        flush(false, true);
+                        translogManager.trimUnreferencedTranslogFiles();
+                    }
+
+                    @Override
+                    public void onFailure(String reason, Exception ex) {
+                        if (ex instanceof AlreadyClosedException) {
+                            failOnTragicEvent((AlreadyClosedException) ex);
+                        } else {
+                            failEngine(reason, ex);
+                        }
+                    }
+                };
+                translogManagerRef = new InternalTranslogManager(
+                    engineConfig.getTranslogConfig(),
+                    engineConfig.getPrimaryTermSupplier(),
+                    engineConfig.getGlobalCheckpointSupplier(),
+                    translogDeletionPolicy,
+                    shardId,
+                    readLock,
+                    this::getLocalCheckpointTracker,
+                    translogUUID,
+                    new CompositeTranslogEventListener(Arrays.asList(internalTranslogEventListener, translogEventListener), shardId),
+                    this::ensureOpen,
+                    engineConfig.getTranslogFactory(),
+                    engineConfig.getPrimaryModeSupplier()
+                );
+                this.translogManager = translogManagerRef;
                 this.softDeletesPolicy = newSoftDeletesPolicy();
                 this.combinedDeletionPolicy = new CombinedDeletionPolicy(
                     logger,
                     translogDeletionPolicy,
                     softDeletesPolicy,
-                    translog::getLastSyncedGlobalCheckpoint
+                    translogManager::getLastSyncedGlobalCheckpoint
                 );
                 this.localCheckpointTracker = createLocalCheckpointTracker(localCheckpointTrackerSupplier);
                 writer = createWriter();
@@ -290,9 +325,6 @@ public InternalEngine(EngineConfig engineConfig) {
             this.internalReaderManager = internalReaderManager;
             this.externalReaderManager = externalReaderManager;
             internalReaderManager.addListener(versionMap);
-            assert pendingTranslogRecovery.get() == false : "translog recovery can't be pending before we set it";
-            // don't allow commits until we are done with recovering
-            pendingTranslogRecovery.set(true);
             for (ReferenceManager.RefreshListener listener : engineConfig.getExternalRefreshListener()) {
                 this.externalReaderManager.addListener(listener);
             }
@@ -301,7 +333,9 @@ public InternalEngine(EngineConfig engineConfig) {
             }
             this.lastRefreshedCheckpointListener = new LastRefreshedCheckpointListener(localCheckpointTracker.getProcessedCheckpoint());
             this.internalReaderManager.addListener(lastRefreshedCheckpointListener);
-            maxSeqNoOfUpdatesOrDeletes = new AtomicLong(SequenceNumbers.max(localCheckpointTracker.getMaxSeqNo(), translog.getMaxSeqNo()));
+            maxSeqNoOfUpdatesOrDeletes = new AtomicLong(
+                SequenceNumbers.max(localCheckpointTracker.getMaxSeqNo(), translogManager.getMaxSeqNo())
+            );
             if (localCheckpointTracker.getPersistedCheckpoint() < localCheckpointTracker.getMaxSeqNo()) {
                 try (Searcher searcher = acquireSearcher("restore_version_map_and_checkpoint_tracker", SearcherScope.INTERNAL)) {
                     restoreVersionMapAndCheckpointTracker(Lucene.wrapAllDocsLive(searcher.getDirectoryReader()));
@@ -318,7 +352,7 @@ public InternalEngine(EngineConfig engineConfig) {
             success = true;
         } finally {
             if (success == false) {
-                IOUtils.closeWhileHandlingException(writer, translog, internalReaderManager, externalReaderManager, scheduler);
+                IOUtils.closeWhileHandlingException(writer, translogManagerRef, internalReaderManager, externalReaderManager, scheduler);
                 if (isClosed.get() == false) {
                     // failure we need to dec the store reference
                     store.decRef();
@@ -351,7 +385,7 @@ private SoftDeletesPolicy newSoftDeletesPolicy() throws IOException {
             lastMinRetainedSeqNo = Long.parseLong(commitUserData.get(SequenceNumbers.MAX_SEQ_NO)) + 1;
         }
         return new SoftDeletesPolicy(
-            translog::getLastSyncedGlobalCheckpoint,
+            translogManager::getLastSyncedGlobalCheckpoint,
             lastMinRetainedSeqNo,
             engineConfig.getIndexSettings().getSoftDeleteRetentionOperations(),
             engineConfig.retentionLeasesSupplier()
@@ -373,6 +407,8 @@ public CompletionStats completionStats(String... fieldNamePatterns) {
      * since no indexing is happening and refreshes are only happening to the external reader manager, while with
      * this specialized implementation an external refresh will immediately be reflected on the internal reader
      * and old segments can be released in the same way previous version did this (as a side-effect of _refresh)
+     *
+     * @opensearch.internal
      */
     @SuppressForbidden(reason = "reference counting is required here")
     private static final class ExternalReaderManager extends ReferenceManager<OpenSearchDirectoryReader> {
@@ -453,7 +489,7 @@ public int restoreLocalHistoryFromTranslog(TranslogRecoveryRunner translogRecove
         try (ReleasableLock ignored = readLock.acquire()) {
             ensureOpen();
             final long localCheckpoint = localCheckpointTracker.getProcessedCheckpoint();
-            try (Translog.Snapshot snapshot = getTranslog().newSnapshot(localCheckpoint + 1, Long.MAX_VALUE)) {
+            try (Translog.Snapshot snapshot = translogManager().getTranslog().newSnapshot(localCheckpoint + 1, Long.MAX_VALUE)) {
                 return translogRecoveryRunner.run(this, snapshot);
             }
         }
@@ -477,7 +513,7 @@ public int fillSeqNoGaps(long primaryTerm) throws IOException {
                     + "]";
 
             }
-            syncTranslog(); // to persist noops associated with the advancement of the local checkpoint
+            translogManager.syncTranslog(); // to persist noops associated with the advancement of the local checkpoint
             assert localCheckpointTracker.getPersistedCheckpoint() == maxSeqNo
                 : "persisted local checkpoint did not advance to max seq no; is ["
                     + localCheckpointTracker.getPersistedCheckpoint()
@@ -503,14 +539,15 @@ private void bootstrapAppendOnlyInfoFromWriter(IndexWriter writer) {
     public InternalEngine recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException {
         try (ReleasableLock lock = readLock.acquire()) {
             ensureOpen();
-            if (pendingTranslogRecovery.get() == false) {
+            if (translogManager.getPendingTranslogRecovery().get() == false) {
                 throw new IllegalStateException("Engine has already been recovered");
             }
             try {
                 recoverFromTranslogInternal(translogRecoveryRunner, recoverUpToSeqNo);
             } catch (Exception e) {
                 try {
-                    pendingTranslogRecovery.set(true); // just play safe and never allow commits on this see #ensureCanFlush
+                    translogManager.getPendingTranslogRecovery().set(true); // just play safe and never allow commits on this see
+                                                                            // #ensureCanFlush
                     failEngine("failed to recover from translog", e);
                 } catch (Exception inner) {
                     e.addSuppressed(inner);
@@ -523,15 +560,14 @@ public InternalEngine recoverFromTranslog(TranslogRecoveryRunner translogRecover
 
     @Override
     public void skipTranslogRecovery() {
-        assert pendingTranslogRecovery.get() : "translogRecovery is not pending but should be";
-        pendingTranslogRecovery.set(false); // we are good - now we can commit
+        translogManager.skipTranslogRecovery();
     }
 
     private void recoverFromTranslogInternal(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException {
         final int opsRecovered;
         final long localCheckpoint = getProcessedLocalCheckpoint();
         if (localCheckpoint < recoverUpToSeqNo) {
-            try (Translog.Snapshot snapshot = translog.newSnapshot(localCheckpoint + 1, recoverUpToSeqNo)) {
+            try (Translog.Snapshot snapshot = translogManager.getTranslog().newSnapshot(localCheckpoint + 1, recoverUpToSeqNo)) {
                 opsRecovered = translogRecoveryRunner.run(this, snapshot);
             } catch (Exception e) {
                 throw new EngineException(shardId, "failed to recover from translog", e);
@@ -541,44 +577,17 @@ private void recoverFromTranslogInternal(TranslogRecoveryRunner translogRecovery
         }
         // flush if we recovered something or if we have references to older translogs
         // note: if opsRecovered == 0 and we have older translogs it means they are corrupted or 0 length.
-        assert pendingTranslogRecovery.get() : "translogRecovery is not pending but should be";
-        pendingTranslogRecovery.set(false); // we are good - now we can commit
+        assert translogManager.getPendingTranslogRecovery().get() : "translogRecovery is not pending but should be";
+        translogManager.getPendingTranslogRecovery().set(false); // we are good - now we can commit
         logger.trace(
             () -> new ParameterizedMessage(
                 "flushing post recovery from translog: ops recovered [{}], current translog generation [{}]",
                 opsRecovered,
-                translog.currentFileGeneration()
+                translogManager.getTranslog().currentFileGeneration()
             )
         );
         flush(false, true);
-        translog.trimUnreferencedReaders();
-    }
-
-    private Translog openTranslog(
-        EngineConfig engineConfig,
-        TranslogDeletionPolicy translogDeletionPolicy,
-        LongSupplier globalCheckpointSupplier,
-        LongConsumer persistedSequenceNumberConsumer
-    ) throws IOException {
-
-        final TranslogConfig translogConfig = engineConfig.getTranslogConfig();
-        final Map<String, String> userData = store.readLastCommittedSegmentsInfo().getUserData();
-        final String translogUUID = Objects.requireNonNull(userData.get(Translog.TRANSLOG_UUID_KEY));
-        // We expect that this shard already exists, so it must already have an existing translog else something is badly wrong!
-        return new Translog(
-            translogConfig,
-            translogUUID,
-            translogDeletionPolicy,
-            globalCheckpointSupplier,
-            engineConfig.getPrimaryTermSupplier(),
-            persistedSequenceNumberConsumer
-        );
-    }
-
-    // Package private for testing purposes only
-    Translog getTranslog() {
-        ensureOpen();
-        return translog;
+        translogManager.trimUnreferencedReaders();
     }
 
     // Package private for testing purposes only
@@ -588,39 +597,38 @@ boolean hasSnapshottedCommits() {
 
     @Override
     public boolean isTranslogSyncNeeded() {
-        return getTranslog().syncNeeded();
+        return translogManager.isTranslogSyncNeeded();
     }
 
     @Override
     public boolean ensureTranslogSynced(Stream<Translog.Location> locations) throws IOException {
-        final boolean synced = translog.ensureSynced(locations);
-        if (synced) {
-            revisitIndexDeletionPolicyOnTranslogSynced();
-        }
-        return synced;
+        return translogManager.ensureTranslogSynced(locations);
     }
 
     @Override
     public void syncTranslog() throws IOException {
-        translog.sync();
-        revisitIndexDeletionPolicyOnTranslogSynced();
+        translogManager.syncTranslog();
     }
 
     @Override
     public TranslogStats getTranslogStats() {
-        return getTranslog().stats();
+        return translogManager.getTranslogStats();
     }
 
     @Override
     public Translog.Location getTranslogLastWriteLocation() {
-        return getTranslog().getLastWriteLocation();
+        return translogManager.getTranslogLastWriteLocation();
     }
 
-    private void revisitIndexDeletionPolicyOnTranslogSynced() throws IOException {
-        if (combinedDeletionPolicy.hasUnreferencedCommits()) {
-            indexWriter.deleteUnusedFiles();
+    private void revisitIndexDeletionPolicyOnTranslogSynced() {
+        try {
+            if (combinedDeletionPolicy.hasUnreferencedCommits()) {
+                indexWriter.deleteUnusedFiles();
+            }
+            translogManager.trimUnreferencedReaders();
+        } catch (IOException ex) {
+            throw new TranslogException(shardId, "Failed to execute index deletion policy on translog synced", ex);
         }
-        translog.trimUnreferencedReaders();
     }
 
     @Override
@@ -640,17 +648,6 @@ public long getWritingBytes() {
         return indexWriter.getFlushingBytes() + versionMap.getRefreshingBytes();
     }
 
-    /**
-     * Reads the current stored history ID from the IW commit data.
-     */
-    private String loadHistoryUUID(Map<String, String> commitData) {
-        final String uuid = commitData.get(HISTORY_UUID_KEY);
-        if (uuid == null) {
-            throw new IllegalStateException("commit doesn't contain history uuid");
-        }
-        return uuid;
-    }
-
     private ExternalReaderManager createReaderManager(RefreshWarmerListener externalRefreshListener) throws EngineException {
         boolean success = false;
         OpenSearchReaderManager internalReaderManager = null;
@@ -720,7 +717,7 @@ public GetResult get(Get get, BiFunction<String, SearcherScope, Engine.Searcher>
                         // the update call doesn't need the consistency since it's source only + _parent but parent can go away in 7.0
                         if (versionValue.getLocation() != null) {
                             try {
-                                Translog.Operation operation = translog.readOperation(versionValue.getLocation());
+                                Translog.Operation operation = translogManager.readOperation(versionValue.getLocation());
                                 if (operation != null) {
                                     // in the case of a already pruned translog generation we might get null here - yet very unlikely
                                     final Translog.Index index = (Translog.Index) operation;
@@ -804,6 +801,7 @@ private OpVsLuceneDocStatus compareOpToLuceneDocBasedOnSeqNo(final Operation op)
         final OpVsLuceneDocStatus status;
         VersionValue versionValue = getVersionFromMap(op.uid().bytes());
         assert incrementVersionLookup();
+        boolean segRepEnabled = engineConfig.getIndexSettings().isSegRepEnabled();
         if (versionValue != null) {
             status = compareOpToVersionMapOnSeqNo(op.id(), op.seqNo(), op.primaryTerm(), versionValue);
         } else {
@@ -816,10 +814,8 @@ private OpVsLuceneDocStatus compareOpToLuceneDocBasedOnSeqNo(final Operation op)
                 } else if (op.seqNo() > docAndSeqNo.seqNo) {
                     status = OpVsLuceneDocStatus.OP_NEWER;
                 } else if (op.seqNo() == docAndSeqNo.seqNo) {
-                    assert localCheckpointTracker.hasProcessed(op.seqNo()) : "local checkpoint tracker is not updated seq_no="
-                        + op.seqNo()
-                        + " id="
-                        + op.id();
+                    assert localCheckpointTracker.hasProcessed(op.seqNo()) || segRepEnabled
+                        : "local checkpoint tracker is not updated seq_no=" + op.seqNo() + " id=" + op.id();
                     status = OpVsLuceneDocStatus.OP_STALE_OR_EQUAL;
                 } else {
                     status = OpVsLuceneDocStatus.OP_STALE_OR_EQUAL;
@@ -1021,11 +1017,12 @@ public IndexResult index(Index index) throws IOException {
                             plan.currentNotFoundOrDeleted
                         );
                     }
+
                 }
                 if (index.origin().isFromTranslog() == false) {
                     final Translog.Location location;
                     if (indexResult.getResultType() == Result.Type.SUCCESS) {
-                        location = translog.add(new Translog.Index(index, indexResult));
+                        location = translogManager.add(new Translog.Index(index, indexResult));
                     } else if (indexResult.getSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO) {
                         // if we have document failure, record it as a no-op in the translog and Lucene with the generated seq_no
                         final NoOp noOp = new NoOp(
@@ -1099,10 +1096,18 @@ protected final IndexingStrategy planIndexingAsNonPrimary(Index index) throws IO
             assert maxSeqNoOfUpdatesOrDeletes < index.seqNo() : index.seqNo() + ">=" + maxSeqNoOfUpdatesOrDeletes;
             plan = IndexingStrategy.optimizedAppendOnly(index.version(), 0);
         } else {
+            boolean segRepEnabled = engineConfig.getIndexSettings().isSegRepEnabled();
             versionMap.enforceSafeAccess();
             final OpVsLuceneDocStatus opVsLucene = compareOpToLuceneDocBasedOnSeqNo(index);
             if (opVsLucene == OpVsLuceneDocStatus.OP_STALE_OR_EQUAL) {
-                plan = IndexingStrategy.processAsStaleOp(index.version());
+                if (segRepEnabled) {
+                    // For segrep based indices, we can't completely rely on localCheckpointTracker
+                    // as the preserved checkpoint may not have all the operations present in lucene
+                    // we don't need to index it again as stale op as it would create multiple documents for same seq no
+                    plan = IndexingStrategy.processButSkipLucene(false, index.version());
+                } else {
+                    plan = IndexingStrategy.processAsStaleOp(index.version());
+                }
             } else {
                 plan = IndexingStrategy.processNormally(opVsLucene == OpVsLuceneDocStatus.LUCENE_DOC_NOT_FOUND, index.version(), 0);
             }
@@ -1289,6 +1294,11 @@ private void addStaleDocs(final List<ParseContext.Document> docs, final IndexWri
         }
     }
 
+    /**
+     * The indexing strategy
+     *
+     * @opensearch.internal
+     */
     protected static final class IndexingStrategy {
         final boolean currentNotFoundOrDeleted;
         final boolean useLuceneUpdateDocument;
@@ -1379,6 +1389,7 @@ private boolean assertDocDoesNotExist(final Index index, final boolean allowDele
             }
         } else {
             try (Searcher searcher = acquireSearcher("assert doc doesn't exist", SearcherScope.INTERNAL)) {
+                searcher.setQueryCache(null);
                 final long docsWithId = searcher.count(new TermQuery(index.uid()));
                 if (docsWithId > 0) {
                     throw new AssertionError("doc [" + index.id() + "] exists [" + docsWithId + "] times in index");
@@ -1460,7 +1471,7 @@ public DeleteResult delete(Delete delete) throws IOException {
                 }
             }
             if (delete.origin().isFromTranslog() == false && deleteResult.getResultType() == Result.Type.SUCCESS) {
-                final Translog.Location location = translog.add(new Translog.Delete(delete, deleteResult));
+                final Translog.Location location = translogManager.add(new Translog.Delete(delete, deleteResult));
                 deleteResult.setTranslogLocation(location);
             }
             localCheckpointTracker.markSeqNoAsProcessed(deleteResult.getSeqNo());
@@ -1530,9 +1541,17 @@ protected final DeletionStrategy planDeletionAsNonPrimary(Delete delete) throws
             // See testRecoveryWithOutOfOrderDelete for an example of peer recovery
             plan = DeletionStrategy.processButSkipLucene(false, delete.version());
         } else {
+            boolean segRepEnabled = engineConfig.getIndexSettings().isSegRepEnabled();
             final OpVsLuceneDocStatus opVsLucene = compareOpToLuceneDocBasedOnSeqNo(delete);
             if (opVsLucene == OpVsLuceneDocStatus.OP_STALE_OR_EQUAL) {
-                plan = DeletionStrategy.processAsStaleOp(delete.version());
+                if (segRepEnabled) {
+                    // For segrep based indices, we can't completely rely on localCheckpointTracker
+                    // as the preserved checkpoint may not have all the operations present in lucene
+                    // we don't need to index it again as stale op as it would create multiple documents for same seq no
+                    plan = DeletionStrategy.processButSkipLucene(false, delete.version());
+                } else {
+                    plan = DeletionStrategy.processAsStaleOp(delete.version());
+                }
             } else {
                 plan = DeletionStrategy.processNormally(opVsLucene == OpVsLuceneDocStatus.LUCENE_DOC_NOT_FOUND, delete.version(), 0);
             }
@@ -1638,6 +1657,11 @@ private DeleteResult deleteInLucene(Delete delete, DeletionStrategy plan) throws
         }
     }
 
+    /**
+     * The deletion strategy
+     *
+     * @opensearch.internal
+     */
     protected static final class DeletionStrategy {
         // of a rare double delete
         final boolean deleteFromLucene;
@@ -1782,7 +1806,9 @@ private NoOpResult innerNoOp(final NoOp noOp) throws IOException {
                 }
                 noOpResult = new NoOpResult(noOp.primaryTerm(), noOp.seqNo());
                 if (noOp.origin().isFromTranslog() == false && noOpResult.getResultType() == Result.Type.SUCCESS) {
-                    final Translog.Location location = translog.add(new Translog.NoOp(noOp.seqNo(), noOp.primaryTerm(), noOp.reason()));
+                    final Translog.Location location = translogManager.add(
+                        new Translog.NoOp(noOp.seqNo(), noOp.primaryTerm(), noOp.reason())
+                    );
                     noOpResult.setTranslogLocation(location);
                 }
             }
@@ -1883,33 +1909,10 @@ public boolean shouldPeriodicallyFlush() {
         final long localCheckpointOfLastCommit = Long.parseLong(
             lastCommittedSegmentInfos.userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)
         );
-        final long translogGenerationOfLastCommit = translog.getMinGenerationForSeqNo(
-            localCheckpointOfLastCommit + 1
-        ).translogFileGeneration;
-        final long flushThreshold = config().getIndexSettings().getFlushThresholdSize().getBytes();
-        if (translog.sizeInBytesByMinGen(translogGenerationOfLastCommit) < flushThreshold) {
-            return false;
-        }
-        /*
-         * We flush to reduce the size of uncommitted translog but strictly speaking the uncommitted size won't always be
-         * below the flush-threshold after a flush. To avoid getting into an endless loop of flushing, we only enable the
-         * periodically flush condition if this condition is disabled after a flush. The condition will change if the new
-         * commit points to the later generation the last commit's(eg. gen-of-last-commit < gen-of-new-commit)[1].
-         *
-         * When the local checkpoint equals to max_seqno, and translog-gen of the last commit equals to translog-gen of
-         * the new commit, we know that the last generation must contain operations because its size is above the flush
-         * threshold and the flush-threshold is guaranteed to be higher than an empty translog by the setting validation.
-         * This guarantees that the new commit will point to the newly rolled generation. In fact, this scenario only
-         * happens when the generation-threshold is close to or above the flush-threshold; otherwise we have rolled
-         * generations as the generation-threshold was reached, then the first condition (eg. [1]) is already satisfied.
-         *
-         * This method is to maintain translog only, thus IndexWriter#hasUncommittedChanges condition is not considered.
-         */
-        final long translogGenerationOfNewCommit = translog.getMinGenerationForSeqNo(
-            localCheckpointTracker.getProcessedCheckpoint() + 1
-        ).translogFileGeneration;
-        return translogGenerationOfLastCommit < translogGenerationOfNewCommit
-            || localCheckpointTracker.getProcessedCheckpoint() == localCheckpointTracker.getMaxSeqNo();
+        return translogManager.shouldPeriodicallyFlush(
+            localCheckpointOfLastCommit,
+            config().getIndexSettings().getFlushThresholdSize().getBytes()
+        );
     }
 
     @Override
@@ -1946,11 +1949,18 @@ public void flush(boolean force, boolean waitIfOngoing) throws EngineException {
                     || getProcessedLocalCheckpoint() > Long.parseLong(
                         lastCommittedSegmentInfos.userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)
                     )) {
-                    ensureCanFlush();
+                    translogManager.ensureCanFlush();
                     try {
-                        translog.rollGeneration();
+                        translogManager.rollTranslogGeneration();
                         logger.trace("starting commit for flush; commitTranslog=true");
-                        commitIndexWriter(indexWriter, translog);
+                        // with Segment Replication we need to hold the latest commit before a new one is created and ensure it is released
+                        // only after the active reader is updated. This ensures that a flush does not wipe out a required commit point file
+                        // while we are
+                        // in refresh listeners.
+                        final GatedCloseable<IndexCommit> latestCommit = engineConfig.getIndexSettings().isSegRepEnabled()
+                            ? acquireLastIndexCommit(false)
+                            : null;
+                        commitIndexWriter(indexWriter, translogManager.getTranslog());
                         logger.trace("finished commit for flush");
 
                         // a temporary debugging to investigate test failure - issue#32827. Remove when the issue is resolved
@@ -1963,7 +1973,12 @@ public void flush(boolean force, boolean waitIfOngoing) throws EngineException {
 
                         // we need to refresh in order to clear older version values
                         refresh("version_table_flush", SearcherScope.INTERNAL, true);
-                        translog.trimUnreferencedReaders();
+
+                        if (latestCommit != null) {
+                            latestCommit.close();
+                        }
+
+                        translogManager.trimUnreferencedReaders();
                     } catch (AlreadyClosedException e) {
                         failOnTragicEvent(e);
                         throw e;
@@ -2018,8 +2033,8 @@ private void refreshLastCommittedSegmentInfos() {
     public void rollTranslogGeneration() throws EngineException {
         try (ReleasableLock ignored = readLock.acquire()) {
             ensureOpen();
-            translog.rollGeneration();
-            translog.trimUnreferencedReaders();
+            translogManager().getTranslog().rollGeneration();
+            translogManager().getTranslog().trimUnreferencedReaders();
         } catch (AlreadyClosedException e) {
             failOnTragicEvent(e);
             throw e;
@@ -2037,7 +2052,7 @@ public void rollTranslogGeneration() throws EngineException {
     public void trimUnreferencedTranslogFiles() throws EngineException {
         try (ReleasableLock lock = readLock.acquire()) {
             ensureOpen();
-            translog.trimUnreferencedReaders();
+            translogManager().getTranslog().trimUnreferencedReaders();
         } catch (AlreadyClosedException e) {
             failOnTragicEvent(e);
             throw e;
@@ -2053,14 +2068,14 @@ public void trimUnreferencedTranslogFiles() throws EngineException {
 
     @Override
     public boolean shouldRollTranslogGeneration() {
-        return getTranslog().shouldRollGeneration();
+        return translogManager().getTranslog().shouldRollGeneration();
     }
 
     @Override
     public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws EngineException {
         try (ReleasableLock lock = readLock.acquire()) {
             ensureOpen();
-            translog.trimOperations(belowTerm, aboveSeqNo);
+            translogManager().getTranslog().trimOperations(belowTerm, aboveSeqNo);
         } catch (AlreadyClosedException e) {
             failOnTragicEvent(e);
             throw e;
@@ -2174,7 +2189,7 @@ public void forceMerge(
             throw ex;
         } catch (Exception e) {
             try {
-                maybeFailEngine("force merge", e);
+                maybeFailEngine(FORCE_MERGE, e);
             } catch (Exception inner) {
                 e.addSuppressed(inner);
             }
@@ -2240,8 +2255,8 @@ private boolean failOnTragicEvent(AlreadyClosedException ex) {
             }
             failEngine("already closed by tragic event on the index writer", tragicException);
             engineFailed = true;
-        } else if (translog.isOpen() == false && translog.getTragicException() != null) {
-            failEngine("already closed by tragic event on the translog", translog.getTragicException());
+        } else if (translogManager.getTragicExceptionIfClosed() != null) {
+            failEngine("already closed by tragic event on the translog", translogManager.getTragicExceptionIfClosed());
             engineFailed = true;
         } else if (failedEngine.get() == null && isClosed.get() == false) { // we are closed but the engine is not failed yet?
             // this smells like a bug - we only expect ACE if we are in a fatal case ie. either translog or IW is closed by
@@ -2266,7 +2281,7 @@ protected boolean maybeFailEngine(String source, Exception e) {
             return failOnTragicEvent((AlreadyClosedException) e);
         } else if (e != null
             && ((indexWriter.isOpen() == false && indexWriter.getTragicException() == e)
-                || (translog.isOpen() == false && translog.getTragicException() == e))) {
+                || (translogManager.getTragicExceptionIfClosed() == e))) {
                     // this spot on - we are handling the tragic event exception here so we have to fail the engine
                     // right away
                     failEngine(source, e);
@@ -2280,6 +2295,36 @@ protected SegmentInfos getLastCommittedSegmentInfos() {
         return lastCommittedSegmentInfos;
     }
 
+    @Override
+    protected SegmentInfos getLatestSegmentInfos() {
+        try (final GatedCloseable<SegmentInfos> snapshot = getSegmentInfosSnapshot()) {
+            return snapshot.get();
+        } catch (IOException e) {
+            throw new EngineException(shardId, e.getMessage(), e);
+        }
+    }
+
+    /**
+     * Fetch the latest {@link SegmentInfos} from the current ReaderManager's active DirectoryReader.
+     * This method will hold the reader reference until the returned {@link GatedCloseable} is closed.
+     */
+    @Override
+    public GatedCloseable<SegmentInfos> getSegmentInfosSnapshot() {
+        final OpenSearchDirectoryReader reader;
+        try {
+            reader = internalReaderManager.acquire();
+            return new GatedCloseable<>(((StandardDirectoryReader) reader.getDelegate()).getSegmentInfos(), () -> {
+                try {
+                    internalReaderManager.release(reader);
+                } catch (AlreadyClosedException e) {
+                    logger.warn("Engine is already closed.", e);
+                }
+            });
+        } catch (IOException e) {
+            throw new EngineException(shardId, e.getMessage(), e);
+        }
+    }
+
     @Override
     protected final void writerSegmentStats(SegmentsStats stats) {
         stats.addVersionMapMemoryInBytes(versionMap.ramBytesUsed());
@@ -2335,7 +2380,7 @@ protected final void closeNoLock(String reason, CountDownLatch closedLatch) {
                     logger.warn("Failed to close ReaderManager", e);
                 }
                 try {
-                    IOUtils.close(translog);
+                    IOUtils.close(translogManager);
                 } catch (Exception e) {
                     logger.warn("Failed to close translog", e);
                 }
@@ -2425,6 +2470,21 @@ private IndexWriterConfig getIndexWriterConfig() {
             // to enable it.
             mergePolicy = new ShuffleForcedMergePolicy(mergePolicy);
         }
+
+        if (config().getIndexSettings().isMergeOnFlushEnabled()) {
+            final long maxFullFlushMergeWaitMillis = config().getIndexSettings().getMaxFullFlushMergeWaitTime().millis();
+            if (maxFullFlushMergeWaitMillis > 0) {
+                iwc.setMaxFullFlushMergeWaitMillis(maxFullFlushMergeWaitMillis);
+                final Optional<UnaryOperator<MergePolicy>> mergeOnFlushPolicy = config().getIndexSettings().getMergeOnFlushPolicy();
+                if (mergeOnFlushPolicy.isPresent()) {
+                    mergePolicy = mergeOnFlushPolicy.get().apply(mergePolicy);
+                }
+            }
+        } else {
+            // Disable merge on refresh
+            iwc.setMaxFullFlushMergeWaitMillis(0);
+        }
+
         iwc.setMergePolicy(new OpenSearchMergePolicy(mergePolicy));
         iwc.setSimilarity(engineConfig.getSimilarity());
         iwc.setRAMBufferSizeMB(engineConfig.getIndexingBufferSize().getMbFrac());
@@ -2433,10 +2493,17 @@ private IndexWriterConfig getIndexWriterConfig() {
         if (config().getIndexSort() != null) {
             iwc.setIndexSort(config().getIndexSort());
         }
+        if (config().getLeafSorter() != null) {
+            iwc.setLeafSorter(config().getLeafSorter()); // The default segment search order
+        }
         return iwc;
     }
 
-    /** A listener that warms the segments if needed when acquiring a new reader */
+    /**
+     * A listener that warms the segments if needed when acquiring a new reader
+     *
+     * @opensearch.internal
+     */
     static final class RefreshWarmerListener implements BiConsumer<OpenSearchDirectoryReader, OpenSearchDirectoryReader> {
         private final Engine.Warmer warmer;
         private final Logger logger;
@@ -2572,7 +2639,7 @@ protected void doRun() throws Exception {
                      * confidence that the call stack does not contain catch statements that would cause the error that might be thrown
                      * here from being caught and never reaching the uncaught exception handler.
                      */
-                    failEngine("merge failed", new MergePolicy.MergeException(exc));
+                    failEngine(MERGE_FAILED, new MergePolicy.MergeException(exc));
                 }
             });
         }
@@ -2585,7 +2652,7 @@ protected void doRun() throws Exception {
      * @param translog the translog
      */
     protected void commitIndexWriter(final IndexWriter writer, final Translog translog) throws IOException {
-        ensureCanFlush();
+        translogManager.ensureCanFlush();
         try {
             final long localCheckpoint = localCheckpointTracker.getProcessedCheckpoint();
             writer.setLiveCommitData(() -> {
@@ -2640,16 +2707,6 @@ protected void commitIndexWriter(final IndexWriter writer, final Translog transl
         }
     }
 
-    final void ensureCanFlush() {
-        // translog recovery happens after the engine is fully constructed.
-        // If we are in this stage we have to prevent flushes from this
-        // engine otherwise we might loose documents if the flush succeeds
-        // and the translog recovery fails when we "commit" the translog on flush.
-        if (pendingTranslogRecovery.get()) {
-            throw new IllegalStateException(shardId.toString() + " flushes are disabled - pending translog recovery");
-        }
-    }
-
     @Override
     public void onSettingsChanged(TimeValue translogRetentionAge, ByteSizeValue translogRetentionSize, long softDeletesRetentionOps) {
         mergeScheduler.refreshConfig();
@@ -2661,7 +2718,7 @@ public void onSettingsChanged(TimeValue translogRetentionAge, ByteSizeValue tran
             // the setting will be re-interpreted if it's set to true
             updateAutoIdTimestamp(Long.MAX_VALUE, true);
         }
-        final TranslogDeletionPolicy translogDeletionPolicy = translog.getDeletionPolicy();
+        final TranslogDeletionPolicy translogDeletionPolicy = translogManager.getDeletionPolicy();
         translogDeletionPolicy.setRetentionAgeInMillis(translogRetentionAge.millis());
         translogDeletionPolicy.setRetentionSizeInBytes(translogRetentionSize.getBytes());
         softDeletesPolicy.setRetentionOperations(softDeletesRetentionOps);
@@ -2677,7 +2734,7 @@ LocalCheckpointTracker getLocalCheckpointTracker() {
 
     @Override
     public long getLastSyncedGlobalCheckpoint() {
-        return getTranslog().getLastSyncedGlobalCheckpoint();
+        return translogManager.getLastSyncedGlobalCheckpoint();
     }
 
     public long getProcessedLocalCheckpoint() {
@@ -2805,6 +2862,20 @@ public Translog.Snapshot newChangesSnapshot(
         }
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link Engine#newChangesSnapshot(String, long, long, boolean, boolean)} instead
+     */
+    @Deprecated
+    @Override
+    public Translog.Snapshot newChangesSnapshotFromTranslogFile(String source, long fromSeqNo, long toSeqNo, boolean requiredFullRange)
+        throws IOException {
+        return translogManager().getTranslog().newSnapshot(fromSeqNo, toSeqNo, requiredFullRange);
+    }
+
     public int countNumberOfHistoryOperations(String source, long fromSeqNo, long toSeqNo) throws IOException {
         ensureOpen();
         refreshIfNeeded(source, toSeqNo);
@@ -2847,6 +2918,11 @@ private static Map<String, String> commitDataAsMap(final IndexWriter indexWriter
         return commitData;
     }
 
+    /**
+     * Internal Asserting Index Writer
+     *
+     * @opensearch.internal
+     */
     private static class AssertingIndexWriter extends IndexWriter {
         AssertingIndexWriter(Directory d, IndexWriterConfig conf) throws IOException {
             super(d, conf);
@@ -2867,10 +2943,17 @@ public long tryDeleteDocument(IndexReader readerIn, int docID) {
     /**
      * Returned the last local checkpoint value has been refreshed internally.
      */
-    final long lastRefreshedCheckpoint() {
+    public final long lastRefreshedCheckpoint() {
         return lastRefreshedCheckpointListener.refreshedCheckpoint.get();
     }
 
+    /**
+     * Returns the current local checkpoint getting refreshed internally.
+     */
+    public final long currentOngoingRefreshCheckpoint() {
+        return lastRefreshedCheckpointListener.pendingCheckpoint.get();
+    }
+
     private final Object refreshIfNeededMutex = new Object();
 
     /**
@@ -2888,28 +2971,33 @@ protected final void refreshIfNeeded(String source, long requestingSeqNo) {
 
     private final class LastRefreshedCheckpointListener implements ReferenceManager.RefreshListener {
         final AtomicLong refreshedCheckpoint;
-        private long pendingCheckpoint;
+        volatile AtomicLong pendingCheckpoint;
 
         LastRefreshedCheckpointListener(long initialLocalCheckpoint) {
             this.refreshedCheckpoint = new AtomicLong(initialLocalCheckpoint);
+            this.pendingCheckpoint = new AtomicLong(initialLocalCheckpoint);
         }
 
         @Override
         public void beforeRefresh() {
             // all changes until this point should be visible after refresh
-            pendingCheckpoint = localCheckpointTracker.getProcessedCheckpoint();
+            pendingCheckpoint.updateAndGet(curr -> Math.max(curr, localCheckpointTracker.getProcessedCheckpoint()));
         }
 
         @Override
         public void afterRefresh(boolean didRefresh) {
             if (didRefresh) {
-                updateRefreshedCheckpoint(pendingCheckpoint);
+                updateRefreshedCheckpoint(pendingCheckpoint.get());
             }
         }
 
         void updateRefreshedCheckpoint(long checkpoint) {
             refreshedCheckpoint.updateAndGet(curr -> Math.max(curr, checkpoint));
             assert refreshedCheckpoint.get() >= checkpoint : refreshedCheckpoint.get() + " < " + checkpoint;
+            // This shouldn't be required ideally, but we're also invoking this method from refresh as of now.
+            // This change is added as safety check to ensure that our checkpoint values are consistent at all times.
+            pendingCheckpoint.updateAndGet(curr -> Math.max(curr, checkpoint));
+
         }
     }
 
@@ -2989,6 +3077,7 @@ private void restoreVersionMapAndCheckpointTracker(DirectoryReader directoryRead
             final CombinedDocValues dv = new CombinedDocValues(leaf.reader());
             final IdOnlyFieldVisitor idFieldVisitor = new IdOnlyFieldVisitor();
             final DocIdSetIterator iterator = scorer.iterator();
+            final StoredFields storedFields = leaf.reader().storedFields();
             int docId;
             while ((docId = iterator.nextDoc()) != DocIdSetIterator.NO_MORE_DOCS) {
                 final long primaryTerm = dv.docPrimaryTerm(docId);
@@ -2996,7 +3085,7 @@ private void restoreVersionMapAndCheckpointTracker(DirectoryReader directoryRead
                 localCheckpointTracker.markSeqNoAsProcessed(seqNo);
                 localCheckpointTracker.markSeqNoAsPersisted(seqNo);
                 idFieldVisitor.reset();
-                leaf.reader().document(docId, idFieldVisitor);
+                storedFields.document(docId, idFieldVisitor);
                 if (idFieldVisitor.getId() == null) {
                     assert dv.isTombstone(docId);
                     continue;
diff --git a/server/src/main/java/org/opensearch/index/engine/InternalEngineFactory.java b/server/src/main/java/org/opensearch/index/engine/InternalEngineFactory.java
index 541c4bb047cd9..d17b417832313 100644
--- a/server/src/main/java/org/opensearch/index/engine/InternalEngineFactory.java
+++ b/server/src/main/java/org/opensearch/index/engine/InternalEngineFactory.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.index.engine;
 
+/**
+ * Factory for creating an in InternalEngine instance
+ *
+ * @opensearch.internal
+ */
 public class InternalEngineFactory implements EngineFactory {
     @Override
     public Engine newReadWriteEngine(EngineConfig config) {
diff --git a/server/src/main/java/org/opensearch/index/engine/LifecycleAware.java b/server/src/main/java/org/opensearch/index/engine/LifecycleAware.java
new file mode 100644
index 0000000000000..06cfb8e7e73a5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/LifecycleAware.java
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+/**
+ * Interface that is aware of a component lifecycle.
+ */
+public interface LifecycleAware {
+
+    /**
+     * Checks to ensure if the component is an open state
+     */
+    void ensureOpen();
+}
diff --git a/server/src/main/java/org/opensearch/index/engine/LiveVersionMap.java b/server/src/main/java/org/opensearch/index/engine/LiveVersionMap.java
index 44715637fd791..87ff449ee74e0 100644
--- a/server/src/main/java/org/opensearch/index/engine/LiveVersionMap.java
+++ b/server/src/main/java/org/opensearch/index/engine/LiveVersionMap.java
@@ -46,11 +46,20 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
 
-/** Maps _uid value to its version information. */
+/**
+ * Maps _uid value to its version information.
+ *
+ * @opensearch.internal
+ */
 final class LiveVersionMap implements ReferenceManager.RefreshListener, Accountable {
 
     private final KeyedLock<BytesRef> keyedLock = new KeyedLock<>();
 
+    /**
+     * Looks up document version
+     *
+     * @opensearch.internal
+     */
     private static final class VersionLookup {
 
         /** Tracks bytes used by current map, i.e. what is freed on refresh. For deletes, which are also added to tombstones,
@@ -116,6 +125,11 @@ public void updateMinDeletedTimestamp(DeleteVersionValue delete) {
 
     }
 
+    /**
+     * Map of version lookups
+     *
+     * @opensearch.internal
+     */
     private static final class Maps {
 
         // All writes (adds and deletes) go into here:
diff --git a/server/src/main/java/org/opensearch/index/engine/LuceneChangesSnapshot.java b/server/src/main/java/org/opensearch/index/engine/LuceneChangesSnapshot.java
index 98da554a5a1b0..00d15478f9866 100644
--- a/server/src/main/java/org/opensearch/index/engine/LuceneChangesSnapshot.java
+++ b/server/src/main/java/org/opensearch/index/engine/LuceneChangesSnapshot.java
@@ -47,10 +47,10 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TopFieldCollector;
 import org.apache.lucene.util.ArrayUtil;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.fieldvisitor.FieldsVisitor;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.SourceFieldMapper;
@@ -64,6 +64,8 @@
 
 /**
  * A {@link Translog.Snapshot} from changes in a Lucene index
+ *
+ * @opensearch.internal
  */
 final class LuceneChangesSnapshot implements Translog.Snapshot {
     static final int DEFAULT_BATCH_SIZE = 1024;
@@ -287,7 +289,7 @@ private Translog.Operation readDocAsOp(int docIndex) throws IOException {
             ? SourceFieldMapper.RECOVERY_SOURCE_NAME
             : SourceFieldMapper.NAME;
         final FieldsVisitor fields = new FieldsVisitor(true, sourceField);
-        leaf.reader().document(segmentDocID, fields);
+        leaf.reader().storedFields().document(segmentDocID, fields);
 
         final Translog.Operation op;
         final boolean isTombstone = parallelArray.isTombStone[docIndex];
@@ -348,6 +350,11 @@ private boolean assertDocSoftDeleted(LeafReader leafReader, int segmentDocId) th
         return ndv.longValue() == 1;
     }
 
+    /**
+     * Parallel array to hold translog operations
+     *
+     * @opensearch.internal
+     */
     private static final class ParallelArray {
         final LeafReaderContext[] leafReaderContexts;
         final long[] version;
diff --git a/server/src/main/java/org/opensearch/index/engine/MissingHistoryOperationsException.java b/server/src/main/java/org/opensearch/index/engine/MissingHistoryOperationsException.java
index 7c7a32a57bf9a..b14e488791f02 100644
--- a/server/src/main/java/org/opensearch/index/engine/MissingHistoryOperationsException.java
+++ b/server/src/main/java/org/opensearch/index/engine/MissingHistoryOperationsException.java
@@ -35,6 +35,8 @@
 /**
  * Exception indicating that not all requested operations from {@link LuceneChangesSnapshot}
  * are available.
+ *
+ * @opensearch.internal
  */
 public final class MissingHistoryOperationsException extends IllegalStateException {
 
diff --git a/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngine.java b/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngine.java
new file mode 100644
index 0000000000000..d5f4480ee02d4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngine.java
@@ -0,0 +1,586 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.index.SoftDeletesDirectoryReaderWrapper;
+import org.apache.lucene.search.ReferenceManager;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.seqno.SeqNoStats;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.TranslogCorruptedException;
+import org.opensearch.index.translog.TranslogDeletionPolicy;
+import org.opensearch.index.translog.TranslogException;
+import org.opensearch.index.translog.TranslogManager;
+import org.opensearch.index.translog.TranslogStats;
+import org.opensearch.index.translog.WriteOnlyTranslogManager;
+import org.opensearch.index.translog.listener.TranslogEventListener;
+import org.opensearch.search.suggest.completion.CompletionStats;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiFunction;
+import java.util.stream.Stream;
+
+import static org.opensearch.index.seqno.SequenceNumbers.MAX_SEQ_NO;
+
+/**
+ * This is an {@link Engine} implementation intended for replica shards when Segment Replication
+ * is enabled.  This Engine does not create an IndexWriter, rather it refreshes a {@link NRTReplicationReaderManager}
+ * with new Segments when received from an external source.
+ *
+ * @opensearch.internal
+ */
+public class NRTReplicationEngine extends Engine implements LifecycleAware {
+
+    private volatile SegmentInfos lastCommittedSegmentInfos;
+    private final NRTReplicationReaderManager readerManager;
+    private final CompletionStatsCache completionStatsCache;
+    private final LocalCheckpointTracker localCheckpointTracker;
+    private final WriteOnlyTranslogManager translogManager;
+    private final Lock flushLock = new ReentrantLock();
+    protected final ReplicaFileTracker replicaFileTracker;
+
+    private volatile long lastReceivedPrimaryGen = SequenceNumbers.NO_OPS_PERFORMED;
+
+    private static final int SI_COUNTER_INCREMENT = 10;
+
+    public NRTReplicationEngine(EngineConfig engineConfig) {
+        super(engineConfig);
+        store.incRef();
+        NRTReplicationReaderManager readerManager = null;
+        WriteOnlyTranslogManager translogManagerRef = null;
+        boolean success = false;
+        try {
+            this.replicaFileTracker = new ReplicaFileTracker(store::deleteQuiet);
+            this.lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
+            // always protect latest commit on disk.
+            replicaFileTracker.incRef(this.lastCommittedSegmentInfos.files(true));
+            // cleanup anything not referenced by the latest infos.
+            cleanUnreferencedFiles();
+            readerManager = buildReaderManager();
+            final SequenceNumbers.CommitInfo commitInfo = SequenceNumbers.loadSeqNoInfoFromLuceneCommit(
+                this.lastCommittedSegmentInfos.getUserData().entrySet()
+            );
+            this.localCheckpointTracker = new LocalCheckpointTracker(commitInfo.maxSeqNo, commitInfo.localCheckpoint);
+            this.completionStatsCache = new CompletionStatsCache(() -> acquireSearcher("completion_stats"));
+            this.readerManager = readerManager;
+            this.readerManager.addListener(completionStatsCache);
+            // NRT Replicas do not have a concept of Internal vs External reader managers.
+            // We also do not want to wire up refresh listeners for waitFor & pending refresh location.
+            // which are the current external listeners set from IndexShard.
+            // Only wire up the internal listeners.
+            for (ReferenceManager.RefreshListener listener : engineConfig.getInternalRefreshListener()) {
+                this.readerManager.addListener(listener);
+            }
+            final Map<String, String> userData = this.lastCommittedSegmentInfos.getUserData();
+            final String translogUUID = Objects.requireNonNull(userData.get(Translog.TRANSLOG_UUID_KEY));
+            translogManagerRef = new WriteOnlyTranslogManager(
+                engineConfig.getTranslogConfig(),
+                engineConfig.getPrimaryTermSupplier(),
+                engineConfig.getGlobalCheckpointSupplier(),
+                getTranslogDeletionPolicy(engineConfig),
+                shardId,
+                readLock,
+                this::getLocalCheckpointTracker,
+                translogUUID,
+                new TranslogEventListener() {
+                    @Override
+                    public void onFailure(String reason, Exception ex) {
+                        failEngine(reason, ex);
+                    }
+
+                    @Override
+                    public void onAfterTranslogSync() {
+                        try {
+                            translogManager.trimUnreferencedReaders();
+                        } catch (IOException ex) {
+                            throw new TranslogException(shardId, "failed to trim unreferenced translog readers", ex);
+                        }
+                    }
+                },
+                this,
+                engineConfig.getTranslogFactory(),
+                engineConfig.getPrimaryModeSupplier()
+            );
+            this.translogManager = translogManagerRef;
+            success = true;
+        } catch (IOException | TranslogCorruptedException e) {
+            throw new EngineCreationFailureException(shardId, "failed to create engine", e);
+        } finally {
+            if (success == false) {
+                IOUtils.closeWhileHandlingException(readerManager, translogManagerRef);
+                if (isClosed.get() == false) {
+                    // failure, we need to dec the store reference
+                    store.decRef();
+                }
+            }
+        }
+    }
+
+    public void cleanUnreferencedFiles() throws IOException {
+        replicaFileTracker.deleteUnreferencedFiles(store.directory().listAll());
+    }
+
+    private NRTReplicationReaderManager buildReaderManager() throws IOException {
+        return new NRTReplicationReaderManager(
+            OpenSearchDirectoryReader.wrap(getDirectoryReader(), shardId),
+            replicaFileTracker::incRef,
+            replicaFileTracker::decRef
+        );
+    }
+
+    public TranslogManager translogManager() {
+        return translogManager;
+    }
+
+    public synchronized void updateSegments(final SegmentInfos infos) throws IOException {
+        try (ReleasableLock lock = writeLock.acquire()) {
+            // Update the current infos reference on the Engine's reader.
+            ensureOpen();
+            final long maxSeqNo = Long.parseLong(infos.userData.get(MAX_SEQ_NO));
+            final long incomingGeneration = infos.getGeneration();
+            readerManager.updateSegments(infos);
+            // Ensure that we commit and clear the local translog if a new commit has been made on the primary.
+            // We do not compare against the last local commit gen here because it is possible to receive
+            // a lower gen from a newly elected primary shard that is behind this shard's last commit gen.
+            // In that case we still commit into the next local generation.
+            if (incomingGeneration != this.lastReceivedPrimaryGen) {
+                flush(false, true);
+                translogManager.getDeletionPolicy().setLocalCheckpointOfSafeCommit(maxSeqNo);
+                translogManager.rollTranslogGeneration();
+            }
+            this.lastReceivedPrimaryGen = incomingGeneration;
+            localCheckpointTracker.fastForwardProcessedSeqNo(maxSeqNo);
+        }
+    }
+
+    /**
+     * Persist the latest live SegmentInfos.
+     *
+     * This method creates a commit point from the latest SegmentInfos.
+     *
+     * @throws IOException - When there is an IO error committing the SegmentInfos.
+     */
+    private void commitSegmentInfos(SegmentInfos infos) throws IOException {
+        // get a reference to the previous commit files so they can be decref'd once a new commit is made.
+        final Collection<String> previousCommitFiles = getLastCommittedSegmentInfos().files(true);
+        store.commitSegmentInfos(infos, localCheckpointTracker.getMaxSeqNo(), localCheckpointTracker.getProcessedCheckpoint());
+        this.lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
+        // incref the latest on-disk commit.
+        replicaFileTracker.incRef(this.lastCommittedSegmentInfos.files(true));
+        // decref the prev commit.
+        replicaFileTracker.decRef(previousCommitFiles);
+        translogManager.syncTranslog();
+    }
+
+    private void commitSegmentInfos() throws IOException {
+        commitSegmentInfos(getLatestSegmentInfos());
+    }
+
+    @Override
+    public String getHistoryUUID() {
+        return loadHistoryUUID(lastCommittedSegmentInfos.userData);
+    }
+
+    @Override
+    public long getWritingBytes() {
+        return 0;
+    }
+
+    @Override
+    public CompletionStats completionStats(String... fieldNamePatterns) {
+        return completionStatsCache.get(fieldNamePatterns);
+    }
+
+    @Override
+    public long getIndexThrottleTimeInMillis() {
+        return 0;
+    }
+
+    @Override
+    public boolean isThrottled() {
+        return false;
+    }
+
+    @Override
+    public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws EngineException {
+        translogManager.trimOperationsFromTranslog(belowTerm, aboveSeqNo);
+    }
+
+    @Override
+    public IndexResult index(Index index) throws IOException {
+        ensureOpen();
+        IndexResult indexResult = new IndexResult(index.version(), index.primaryTerm(), index.seqNo(), false);
+        final Translog.Location location = translogManager.add(new Translog.Index(index, indexResult));
+        indexResult.setTranslogLocation(location);
+        indexResult.setTook(System.nanoTime() - index.startTime());
+        indexResult.freeze();
+        localCheckpointTracker.advanceMaxSeqNo(index.seqNo());
+        return indexResult;
+    }
+
+    @Override
+    public DeleteResult delete(Delete delete) throws IOException {
+        ensureOpen();
+        DeleteResult deleteResult = new DeleteResult(delete.version(), delete.primaryTerm(), delete.seqNo(), true);
+        final Translog.Location location = translogManager.add(new Translog.Delete(delete, deleteResult));
+        deleteResult.setTranslogLocation(location);
+        deleteResult.setTook(System.nanoTime() - delete.startTime());
+        deleteResult.freeze();
+        localCheckpointTracker.advanceMaxSeqNo(delete.seqNo());
+        return deleteResult;
+    }
+
+    @Override
+    public NoOpResult noOp(NoOp noOp) throws IOException {
+        ensureOpen();
+        NoOpResult noOpResult = new NoOpResult(noOp.primaryTerm(), noOp.seqNo());
+        final Translog.Location location = translogManager.add(new Translog.NoOp(noOp.seqNo(), noOp.primaryTerm(), noOp.reason()));
+        noOpResult.setTranslogLocation(location);
+        noOpResult.setTook(System.nanoTime() - noOp.startTime());
+        noOpResult.freeze();
+        localCheckpointTracker.advanceMaxSeqNo(noOp.seqNo());
+        return noOpResult;
+    }
+
+    @Override
+    public GetResult get(Get get, BiFunction<String, SearcherScope, Searcher> searcherFactory) throws EngineException {
+        return getFromSearcher(get, searcherFactory, SearcherScope.EXTERNAL);
+    }
+
+    @Override
+    protected ReferenceManager<OpenSearchDirectoryReader> getReferenceManager(SearcherScope scope) {
+        return readerManager;
+    }
+
+    /**
+     * Refreshing of this engine will only happen internally when a new set of segments is received.  The engine will ignore external
+     * refresh attempts so we can return false here.  Further Engine's existing implementation reads DirectoryReader.isCurrent after acquiring a searcher.
+     * With this Engine's NRTReplicationReaderManager, This will use StandardDirectoryReader's implementation which determines if the reader is current by
+     * comparing the on-disk SegmentInfos version against the one in the reader, which at refresh points will always return isCurrent false and then refreshNeeded true.
+     * Even if this method returns refresh as needed, we ignore it and only ever refresh with incoming SegmentInfos.
+     */
+    @Override
+    public boolean refreshNeeded() {
+        return false;
+    }
+
+    @Override
+    public boolean isTranslogSyncNeeded() {
+        return translogManager.getTranslog().syncNeeded();
+    }
+
+    @Override
+    public boolean ensureTranslogSynced(Stream<Translog.Location> locations) throws IOException {
+        return translogManager.ensureTranslogSynced(locations);
+    }
+
+    @Override
+    public void syncTranslog() throws IOException {
+        translogManager.syncTranslog();
+    }
+
+    @Override
+    public Closeable acquireHistoryRetentionLock() {
+        throw new UnsupportedOperationException("Not implemented");
+    }
+
+    @Override
+    public Translog.Snapshot newChangesSnapshot(
+        String source,
+        long fromSeqNo,
+        long toSeqNo,
+        boolean requiredFullRange,
+        boolean accurateCount
+    ) throws IOException {
+        throw new UnsupportedOperationException("Not implemented");
+    }
+
+    @Deprecated
+    @Override
+    public Translog.Snapshot newChangesSnapshotFromTranslogFile(String source, long fromSeqNo, long toSeqNo, boolean requiredFullRange)
+        throws IOException {
+        return getTranslog().newSnapshot(fromSeqNo, toSeqNo, requiredFullRange);
+    }
+
+    @Override
+    public int countNumberOfHistoryOperations(String source, long fromSeqNo, long toSeqNumber) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public boolean hasCompleteOperationHistory(String reason, long startingSeqNo) {
+        return false;
+    }
+
+    @Override
+    public long getMinRetainedSeqNo() {
+        return localCheckpointTracker.getProcessedCheckpoint();
+    }
+
+    @Override
+    public TranslogStats getTranslogStats() {
+        return translogManager.getTranslog().stats();
+    }
+
+    @Override
+    public Translog.Location getTranslogLastWriteLocation() {
+        return translogManager.getTranslog().getLastWriteLocation();
+    }
+
+    @Override
+    public long getPersistedLocalCheckpoint() {
+        return localCheckpointTracker.getPersistedCheckpoint();
+    }
+
+    public long getProcessedLocalCheckpoint() {
+        return localCheckpointTracker.getProcessedCheckpoint();
+    }
+
+    @Override
+    public SeqNoStats getSeqNoStats(long globalCheckpoint) {
+        return localCheckpointTracker.getStats(globalCheckpoint);
+    }
+
+    @Override
+    public long getLastSyncedGlobalCheckpoint() {
+        return translogManager.getLastSyncedGlobalCheckpoint();
+    }
+
+    @Override
+    public long getIndexBufferRAMBytesUsed() {
+        return 0;
+    }
+
+    @Override
+    public List<Segment> segments(boolean verbose) {
+        return Arrays.asList(getSegmentInfo(getLatestSegmentInfos(), verbose));
+    }
+
+    @Override
+    public void refresh(String source) throws EngineException {
+        // Refresh on this engine should only ever happen in the reader after new segments arrive.
+    }
+
+    @Override
+    public boolean maybeRefresh(String source) throws EngineException {
+        return false;
+    }
+
+    @Override
+    public void writeIndexingBuffer() throws EngineException {}
+
+    @Override
+    public boolean shouldPeriodicallyFlush() {
+        return false;
+    }
+
+    @Override
+    public void flush(boolean force, boolean waitIfOngoing) throws EngineException {
+        ensureOpen();
+        // readLock is held here to wait/block any concurrent close that acquires the writeLock.
+        try (final ReleasableLock lock = readLock.acquire()) {
+            ensureOpen();
+            if (flushLock.tryLock() == false) {
+                if (waitIfOngoing == false) {
+                    return;
+                }
+                flushLock.lock();
+            }
+            // we are now locked.
+            try {
+                commitSegmentInfos();
+            } catch (IOException e) {
+                throw new FlushFailedEngineException(shardId, e);
+            } finally {
+                flushLock.unlock();
+            }
+        }
+    }
+
+    @Override
+    public void trimUnreferencedTranslogFiles() throws EngineException {
+        translogManager.trimUnreferencedTranslogFiles();
+    }
+
+    @Override
+    public boolean shouldRollTranslogGeneration() {
+        return translogManager.getTranslog().shouldRollGeneration();
+    }
+
+    @Override
+    public void rollTranslogGeneration() throws EngineException {
+        translogManager.rollTranslogGeneration();
+    }
+
+    @Override
+    public void forceMerge(
+        boolean flush,
+        int maxNumSegments,
+        boolean onlyExpungeDeletes,
+        boolean upgrade,
+        boolean upgradeOnlyAncientSegments,
+        String forceMergeUUID
+    ) throws EngineException, IOException {}
+
+    @Override
+    public GatedCloseable<IndexCommit> acquireLastIndexCommit(boolean flushFirst) throws EngineException {
+        if (flushFirst) {
+            flush(false, true);
+        }
+        try {
+            final IndexCommit indexCommit = Lucene.getIndexCommit(lastCommittedSegmentInfos, store.directory());
+            return new GatedCloseable<>(indexCommit, () -> {});
+        } catch (IOException e) {
+            throw new EngineException(shardId, "Unable to build latest IndexCommit", e);
+        }
+    }
+
+    @Override
+    public GatedCloseable<IndexCommit> acquireSafeIndexCommit() throws EngineException {
+        return acquireLastIndexCommit(false);
+    }
+
+    @Override
+    public SafeCommitInfo getSafeCommitInfo() {
+        return new SafeCommitInfo(localCheckpointTracker.getProcessedCheckpoint(), lastCommittedSegmentInfos.totalMaxDoc());
+    }
+
+    @Override
+    protected final void closeNoLock(String reason, CountDownLatch closedLatch) {
+        if (isClosed.compareAndSet(false, true)) {
+            assert rwl.isWriteLockedByCurrentThread() || failEngineLock.isHeldByCurrentThread()
+                : "Either the write lock must be held or the engine must be currently be failing itself";
+            try {
+                final SegmentInfos latestSegmentInfos = getLatestSegmentInfos();
+                /*
+                 This is a workaround solution which decreases the chances of conflict on replica nodes when same file is copied
+                 from two different primaries during failover. Increasing counter helps in avoiding this conflict as counter is
+                 used to generate new segment file names. The ideal solution is to identify the counter from previous primary.
+                 This is not required for remote store implementations given on failover the replica re-syncs with the store
+                 during promotion.
+                 */
+                if (engineConfig.getIndexSettings().isRemoteStoreEnabled() == false) {
+                    latestSegmentInfos.counter = latestSegmentInfos.counter + SI_COUNTER_INCREMENT;
+                    latestSegmentInfos.changed();
+                }
+                commitSegmentInfos(latestSegmentInfos);
+                IOUtils.close(readerManager, translogManager, store::decRef);
+            } catch (Exception e) {
+                logger.warn("failed to close engine", e);
+            } finally {
+                logger.debug("engine closed [{}]", reason);
+                closedLatch.countDown();
+            }
+        }
+    }
+
+    @Override
+    public void activateThrottling() {}
+
+    @Override
+    public void deactivateThrottling() {}
+
+    @Override
+    public int restoreLocalHistoryFromTranslog(TranslogRecoveryRunner translogRecoveryRunner) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public int fillSeqNoGaps(long primaryTerm) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public Engine recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException {
+        throw new UnsupportedOperationException("Read only replicas do not have an IndexWriter and cannot recover from a translog.");
+    }
+
+    @Override
+    public void skipTranslogRecovery() {
+        // Do nothing.
+    }
+
+    @Override
+    public void maybePruneDeletes() {}
+
+    @Override
+    public void updateMaxUnsafeAutoIdTimestamp(long newTimestamp) {}
+
+    @Override
+    public long getMaxSeqNoOfUpdatesOrDeletes() {
+        return localCheckpointTracker.getMaxSeqNo();
+    }
+
+    @Override
+    public void advanceMaxSeqNoOfUpdatesOrDeletes(long maxSeqNoOfUpdatesOnPrimary) {}
+
+    public Translog getTranslog() {
+        return translogManager.getTranslog();
+    }
+
+    @Override
+    public void onSettingsChanged(TimeValue translogRetentionAge, ByteSizeValue translogRetentionSize, long softDeletesRetentionOps) {
+        final TranslogDeletionPolicy translogDeletionPolicy = translogManager.getDeletionPolicy();
+        translogDeletionPolicy.setRetentionAgeInMillis(translogRetentionAge.millis());
+        translogDeletionPolicy.setRetentionSizeInBytes(translogRetentionSize.getBytes());
+    }
+
+    @Override
+    protected SegmentInfos getLastCommittedSegmentInfos() {
+        return lastCommittedSegmentInfos;
+    }
+
+    @Override
+    protected SegmentInfos getLatestSegmentInfos() {
+        return readerManager.getSegmentInfos();
+    }
+
+    @Override
+    public synchronized GatedCloseable<SegmentInfos> getSegmentInfosSnapshot() {
+        // get reference to latest infos
+        final SegmentInfos latestSegmentInfos = getLatestSegmentInfos();
+        // incref all files
+        try {
+            final Collection<String> files = latestSegmentInfos.files(false);
+            replicaFileTracker.incRef(files);
+            return new GatedCloseable<>(latestSegmentInfos, () -> { replicaFileTracker.decRef(files); });
+        } catch (IOException e) {
+            throw new EngineException(shardId, e.getMessage(), e);
+        }
+    }
+
+    protected LocalCheckpointTracker getLocalCheckpointTracker() {
+        return localCheckpointTracker;
+    }
+
+    private DirectoryReader getDirectoryReader() throws IOException {
+        // for segment replication: replicas should create the reader from store, we don't want an open IW on replicas.
+        return new SoftDeletesDirectoryReaderWrapper(DirectoryReader.open(store.directory()), Lucene.SOFT_DELETES_FIELD);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngineFactory.java b/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngineFactory.java
new file mode 100644
index 0000000000000..45fe3086ac3f6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/NRTReplicationEngineFactory.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+/**
+ * Engine Factory implementation used with Segment Replication that wires up replica shards with an ${@link NRTReplicationEngine}
+ * and primary with an ${@link InternalEngine}
+ *
+ * @opensearch.internal
+ */
+public class NRTReplicationEngineFactory implements EngineFactory {
+    @Override
+    public Engine newReadWriteEngine(EngineConfig config) {
+        if (config.isReadOnlyReplica()) {
+            return new NRTReplicationEngine(config);
+        }
+        return new InternalEngine(config);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/engine/NRTReplicationReaderManager.java b/server/src/main/java/org/opensearch/index/engine/NRTReplicationReaderManager.java
new file mode 100644
index 0000000000000..7b4c93c7235fe
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/NRTReplicationReaderManager.java
@@ -0,0 +1,120 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.index.SoftDeletesDirectoryReaderWrapper;
+import org.apache.lucene.index.StandardDirectoryReader;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+/**
+ * This is an extension of {@link OpenSearchReaderManager} for use with {@link NRTReplicationEngine}.
+ * The manager holds a reference to the latest {@link SegmentInfos} object that is used to refresh a reader.
+ *
+ * @opensearch.internal
+ */
+public class NRTReplicationReaderManager extends OpenSearchReaderManager {
+
+    private final static Logger logger = LogManager.getLogger(NRTReplicationReaderManager.class);
+    private volatile SegmentInfos currentInfos;
+    private Consumer<Collection<String>> onReaderClosed;
+    private Consumer<Collection<String>> onNewReader;
+
+    /**
+     * Creates and returns a new SegmentReplicationReaderManager from the given
+     * already-opened {@link OpenSearchDirectoryReader}, stealing
+     * the incoming reference.
+     *
+     * @param reader         - The SegmentReplicationReaderManager to use for future reopens.
+     * @param onNewReader    - Called when a new reader is created.
+     * @param onReaderClosed - Called when a reader is closed.
+     */
+    NRTReplicationReaderManager(
+        OpenSearchDirectoryReader reader,
+        Consumer<Collection<String>> onNewReader,
+        Consumer<Collection<String>> onReaderClosed
+    ) {
+        super(reader);
+        currentInfos = unwrapStandardReader(reader).getSegmentInfos();
+        this.onNewReader = onNewReader;
+        this.onReaderClosed = onReaderClosed;
+    }
+
+    @Override
+    protected OpenSearchDirectoryReader refreshIfNeeded(OpenSearchDirectoryReader referenceToRefresh) throws IOException {
+        Objects.requireNonNull(referenceToRefresh);
+        // checks if an actual refresh (change in segments) happened
+        if (unwrapStandardReader(referenceToRefresh).getSegmentInfos().version == currentInfos.version) {
+            return null;
+        }
+        final List<LeafReader> subs = new ArrayList<>();
+        final StandardDirectoryReader standardDirectoryReader = unwrapStandardReader(referenceToRefresh);
+        for (LeafReaderContext ctx : standardDirectoryReader.leaves()) {
+            subs.add(ctx.reader());
+        }
+        // Segment_n here is ignored because it is either already committed on disk as part of previous commit point or
+        // does not yet exist on store (not yet committed)
+        final Collection<String> files = currentInfos.files(false);
+        DirectoryReader innerReader = StandardDirectoryReader.open(referenceToRefresh.directory(), currentInfos, subs, null);
+        final DirectoryReader softDeletesDirectoryReaderWrapper = new SoftDeletesDirectoryReaderWrapper(
+            innerReader,
+            Lucene.SOFT_DELETES_FIELD
+        );
+        logger.trace(
+            () -> new ParameterizedMessage("updated to SegmentInfosVersion=" + currentInfos.getVersion() + " reader=" + innerReader)
+        );
+        final OpenSearchDirectoryReader reader = OpenSearchDirectoryReader.wrap(
+            softDeletesDirectoryReaderWrapper,
+            referenceToRefresh.shardId()
+        );
+        onNewReader.accept(files);
+        OpenSearchDirectoryReader.addReaderCloseListener(reader, key -> onReaderClosed.accept(files));
+        return reader;
+    }
+
+    /**
+     * Update this reader's segments and refresh.
+     *
+     * @param infos {@link SegmentInfos} infos
+     * @throws IOException - When Refresh fails with an IOException.
+     */
+    public void updateSegments(SegmentInfos infos) throws IOException {
+        // roll over the currentInfo's generation, this ensures the on-disk gen
+        // is always increased.
+        infos.updateGeneration(currentInfos);
+        currentInfos = infos;
+        maybeRefresh();
+    }
+
+    public SegmentInfos getSegmentInfos() {
+        return currentInfos;
+    }
+
+    public static StandardDirectoryReader unwrapStandardReader(OpenSearchDirectoryReader reader) {
+        final DirectoryReader delegate = reader.getDelegate();
+        if (delegate instanceof SoftDeletesDirectoryReaderWrapper) {
+            return (StandardDirectoryReader) ((SoftDeletesDirectoryReaderWrapper) delegate).getDelegate();
+        }
+        return (StandardDirectoryReader) delegate;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/engine/NoOpEngine.java b/server/src/main/java/org/opensearch/index/engine/NoOpEngine.java
index 5db1bb05bbc24..0fa5c6bac1fdd 100644
--- a/server/src/main/java/org/opensearch/index/engine/NoOpEngine.java
+++ b/server/src/main/java/org/opensearch/index/engine/NoOpEngine.java
@@ -44,10 +44,14 @@
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.DocsStats;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
+import org.opensearch.index.translog.LocalTranslog;
+import org.opensearch.index.translog.NoOpTranslogManager;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
-import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
 import org.opensearch.index.translog.TranslogDeletionPolicy;
+import org.opensearch.index.translog.TranslogException;
+import org.opensearch.index.translog.TranslogManager;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -61,6 +65,8 @@
  * index, get), throw {@link UnsupportedOperationException}. However, NoOpEngine
  * allows to trim any existing translog files through the usage of the
  * {{@link #trimUnreferencedTranslogFiles()}} method.
+ *
+ * @opensearch.internal
  */
 public final class NoOpEngine extends ReadOnlyEngine {
 
@@ -147,6 +153,94 @@ public DocsStats docStats() {
         return docsStats;
     }
 
+    /**
+     * This implementation will trim existing translog files using a {@link TranslogDeletionPolicy}
+     * that retains nothing but the last translog generation from safe commit.
+     */
+    public TranslogManager translogManager() {
+        try {
+            return new NoOpTranslogManager(shardId, readLock, this::ensureOpen, this.translogStats, new Translog.Snapshot() {
+                @Override
+                public void close() {}
+
+                @Override
+                public int totalOperations() {
+                    return 0;
+                }
+
+                @Override
+                public Translog.Operation next() {
+                    return null;
+                }
+
+            }) {
+                /**
+                 * This implementation will trim existing translog files using a {@link TranslogDeletionPolicy}
+                 * that retains nothing but the last translog generation from safe commit.
+                 */
+                @Override
+                public void trimUnreferencedTranslogFiles() throws TranslogException {
+                    final Store store = engineConfig.getStore();
+                    store.incRef();
+                    try (ReleasableLock ignored = readLock.acquire()) {
+                        ensureOpen();
+                        final List<IndexCommit> commits = DirectoryReader.listCommits(store.directory());
+                        if (commits.size() == 1 && translogStats.getTranslogSizeInBytes() > translogStats.getUncommittedSizeInBytes()) {
+                            final Map<String, String> commitUserData = getLastCommittedSegmentInfos().getUserData();
+                            final String translogUuid = commitUserData.get(Translog.TRANSLOG_UUID_KEY);
+                            if (translogUuid == null) {
+                                throw new IllegalStateException("commit doesn't contain translog unique id");
+                            }
+                            final TranslogConfig translogConfig = engineConfig.getTranslogConfig();
+                            final long localCheckpoint = Long.parseLong(commitUserData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
+                            final TranslogDeletionPolicy translogDeletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
+                            translogDeletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+                            try (
+                                Translog translog = engineConfig.getTranslogFactory()
+                                    .newTranslog(
+                                        translogConfig,
+                                        translogUuid,
+                                        translogDeletionPolicy,
+                                        engineConfig.getGlobalCheckpointSupplier(),
+                                        engineConfig.getPrimaryTermSupplier(),
+                                        seqNo -> {},
+                                        engineConfig.getPrimaryModeSupplier()
+                                    )
+                            ) {
+                                translog.trimUnreferencedReaders();
+                                // refresh the translog stats
+                                translogStats = translog.stats();
+                                // When remote translog is enabled, the min file generation is dependent on the (N-1)
+                                // lastRefreshedCheckpoint SeqNo - refer RemoteStoreRefreshListener. This leads to older generations not
+                                // being trimmed and leading to current generation being higher than the min file generation.
+                                assert engineConfig.getIndexSettings().isRemoteTranslogStoreEnabled()
+                                    || translog.currentFileGeneration() == translog.getMinFileGeneration() : "translog was not trimmed "
+                                        + " current gen "
+                                        + translog.currentFileGeneration()
+                                        + " != min gen "
+                                        + translog.getMinFileGeneration();
+                            }
+                        }
+                    } catch (final Exception e) {
+                        try {
+                            failEngine("translog trimming failed", e);
+                        } catch (Exception inner) {
+                            e.addSuppressed(inner);
+                        }
+                        throw new EngineException(shardId, "failed to trim translog", e);
+                    } finally {
+                        store.decRef();
+                    }
+                }
+
+                @Override
+                public void setMinSeqNoToKeep(long seqNo) {}
+            };
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
     /**
      * This implementation will trim existing translog files using a {@link TranslogDeletionPolicy}
      * that retains nothing but the last translog generation from safe commit.
@@ -169,7 +263,7 @@ public void trimUnreferencedTranslogFiles() {
                 final TranslogDeletionPolicy translogDeletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
                 translogDeletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
                 try (
-                    Translog translog = new Translog(
+                    Translog translog = new LocalTranslog(
                         translogConfig,
                         translogUuid,
                         translogDeletionPolicy,
diff --git a/server/src/main/java/org/opensearch/index/engine/OpenSearchConcurrentMergeScheduler.java b/server/src/main/java/org/opensearch/index/engine/OpenSearchConcurrentMergeScheduler.java
index 9deab15991f38..c57c0090c180b 100644
--- a/server/src/main/java/org/opensearch/index/engine/OpenSearchConcurrentMergeScheduler.java
+++ b/server/src/main/java/org/opensearch/index/engine/OpenSearchConcurrentMergeScheduler.java
@@ -41,15 +41,15 @@
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MergeSchedulerConfig;
 import org.opensearch.index.merge.MergeStats;
 import org.opensearch.index.merge.OnGoingMerge;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -59,6 +59,8 @@
 /**
  * An extension to the {@link ConcurrentMergeScheduler} that provides tracking on merge times, total
  * and current merges.
+ *
+ * @opensearch.internal
  */
 class OpenSearchConcurrentMergeScheduler extends ConcurrentMergeScheduler {
 
diff --git a/server/src/main/java/org/opensearch/index/engine/OpenSearchReaderManager.java b/server/src/main/java/org/opensearch/index/engine/OpenSearchReaderManager.java
index b83ce8bea567c..e1a8f29612871 100644
--- a/server/src/main/java/org/opensearch/index/engine/OpenSearchReaderManager.java
+++ b/server/src/main/java/org/opensearch/index/engine/OpenSearchReaderManager.java
@@ -32,15 +32,14 @@
 
 package org.opensearch.index.engine;
 
-import java.io.IOException;
-
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.search.ReferenceManager;
-
 import org.apache.lucene.search.SearcherManager;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 
+import java.io.IOException;
+
 /**
  * Utility class to safely share {@link OpenSearchDirectoryReader} instances across
  * multiple threads, while periodically reopening. This class ensures each
@@ -48,6 +47,7 @@
  *
  * @see SearcherManager
  *
+ * @opensearch.internal
  */
 @SuppressForbidden(reason = "reference counting is required here")
 class OpenSearchReaderManager extends ReferenceManager<OpenSearchDirectoryReader> {
diff --git a/server/src/main/java/org/opensearch/index/engine/PrunePostingsMergePolicy.java b/server/src/main/java/org/opensearch/index/engine/PrunePostingsMergePolicy.java
index 18f2799edc244..87ac032b7d81b 100644
--- a/server/src/main/java/org/opensearch/index/engine/PrunePostingsMergePolicy.java
+++ b/server/src/main/java/org/opensearch/index/engine/PrunePostingsMergePolicy.java
@@ -59,6 +59,8 @@
  * soft deleted documents independent of the retention policy. Note, in order for this merge policy to be effective it needs to be added
  * before the {@link org.apache.lucene.index.SoftDeletesRetentionMergePolicy} because otherwise only documents that are deleted / removed
  * anyways will be pruned.
+ *
+ * @opensearch.internal
  */
 final class PrunePostingsMergePolicy extends OneMergeWrappingMergePolicy {
 
@@ -166,6 +168,11 @@ public CacheHelper getReaderCacheHelper() {
         };
     }
 
+    /**
+     * Class holder for only live docs and the postings enumerator
+     *
+     * @opensearch.internal
+     */
     private static final class OnlyLiveDocsPostingsEnum extends PostingsEnum {
 
         private final Bits liveDocs;
diff --git a/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java b/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java
index 43fe10c217270..c0ed9294353f5 100644
--- a/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java
+++ b/server/src/main/java/org/opensearch/index/engine/ReadOnlyEngine.java
@@ -45,14 +45,16 @@
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
+import org.opensearch.index.translog.NoOpTranslogManager;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
 import org.opensearch.index.translog.TranslogDeletionPolicy;
+import org.opensearch.index.translog.TranslogManager;
 import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.search.suggest.completion.CompletionStats;
 import org.opensearch.transport.Transports;
@@ -73,6 +75,8 @@
  * engine.
  *
  * @see #ReadOnlyEngine(EngineConfig, SeqNoStats, TranslogStats, boolean, Function, boolean)
+ *
+ * @opensearch.internal
  */
 public class ReadOnlyEngine extends Engine {
 
@@ -88,6 +92,8 @@ public class ReadOnlyEngine extends Engine {
     private final SafeCommitInfo safeCommitInfo;
     private final CompletionStatsCache completionStatsCache;
     private final boolean requireCompleteHistory;
+    private final TranslogManager translogManager;
+    private final Version minimumSupportedVersion;
 
     protected volatile TranslogStats translogStats;
 
@@ -114,6 +120,8 @@ public ReadOnlyEngine(
     ) {
         super(config);
         this.requireCompleteHistory = requireCompleteHistory;
+        // fetch the minimum Version for extended backward compatibility use-cases
+        this.minimumSupportedVersion = config.getIndexSettings().getExtendedCompatibilitySnapshotVersion();
         try {
             Store store = config.getStore();
             store.incRef();
@@ -125,7 +133,11 @@ public ReadOnlyEngine(
                 // we obtain the IW lock even though we never modify the index.
                 // yet this makes sure nobody else does. including some testing tools that try to be messy
                 indexWriterLock = obtainLock ? directory.obtainLock(IndexWriter.WRITE_LOCK_NAME) : null;
-                this.lastCommittedSegmentInfos = Lucene.readSegmentInfos(directory);
+                if (isExtendedCompatibility()) {
+                    this.lastCommittedSegmentInfos = Lucene.readSegmentInfos(directory, this.minimumSupportedVersion);
+                } else {
+                    this.lastCommittedSegmentInfos = Lucene.readSegmentInfos(directory);
+                }
                 if (seqNoStats == null) {
                     seqNoStats = buildSeqNoStats(config, lastCommittedSegmentInfos);
                     ensureMaxSeqNoEqualsToGlobalCheckpoint(seqNoStats);
@@ -141,6 +153,21 @@ public ReadOnlyEngine(
 
                 completionStatsCache = new CompletionStatsCache(() -> acquireSearcher("completion_stats"));
 
+                translogManager = new NoOpTranslogManager(shardId, readLock, this::ensureOpen, this.translogStats, new Translog.Snapshot() {
+                    @Override
+                    public void close() {}
+
+                    @Override
+                    public int totalOperations() {
+                        return 0;
+                    }
+
+                    @Override
+                    public Translog.Operation next() {
+                        return null;
+                    }
+                });
+
                 success = true;
             } finally {
                 if (success == false) {
@@ -203,7 +230,17 @@ protected final OpenSearchDirectoryReader wrapReader(
 
     protected DirectoryReader open(IndexCommit commit) throws IOException {
         assert Transports.assertNotTransportThread("opening index commit of a read-only engine");
-        return new SoftDeletesDirectoryReaderWrapper(DirectoryReader.open(commit), Lucene.SOFT_DELETES_FIELD);
+        DirectoryReader reader;
+        if (isExtendedCompatibility()) {
+            reader = DirectoryReader.open(commit, this.minimumSupportedVersion.luceneVersion.major, null);
+        } else {
+            reader = DirectoryReader.open(commit);
+        }
+        return new SoftDeletesDirectoryReaderWrapper(reader, Lucene.SOFT_DELETES_FIELD);
+    }
+
+    private boolean isExtendedCompatibility() {
+        return Version.CURRENT.minimumIndexCompatibilityVersion().onOrAfter(this.minimumSupportedVersion);
     }
 
     @Override
@@ -240,14 +277,16 @@ private static TranslogStats translogStats(final EngineConfig config, final Segm
         final long localCheckpoint = Long.parseLong(infos.getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
         translogDeletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
         try (
-            Translog translog = new Translog(
-                translogConfig,
-                translogUuid,
-                translogDeletionPolicy,
-                config.getGlobalCheckpointSupplier(),
-                config.getPrimaryTermSupplier(),
-                seqNo -> {}
-            )
+            Translog translog = config.getTranslogFactory()
+                .newTranslog(
+                    translogConfig,
+                    translogUuid,
+                    translogDeletionPolicy,
+                    config.getGlobalCheckpointSupplier(),
+                    config.getPrimaryTermSupplier(),
+                    seqNo -> {},
+                    config.getPrimaryModeSupplier()
+                )
         ) {
             return translog.stats();
         }
@@ -263,11 +302,20 @@ protected ReferenceManager<OpenSearchDirectoryReader> getReferenceManager(Search
         return readerManager;
     }
 
+    public TranslogManager translogManager() {
+        return translogManager;
+    }
+
     @Override
     protected SegmentInfos getLastCommittedSegmentInfos() {
         return lastCommittedSegmentInfos;
     }
 
+    @Override
+    protected SegmentInfos getLatestSegmentInfos() {
+        return lastCommittedSegmentInfos;
+    }
+
     @Override
     public String getHistoryUUID() {
         return lastCommittedSegmentInfos.userData.get(Engine.HISTORY_UUID_KEY);
@@ -308,16 +356,18 @@ public NoOpResult noOp(NoOp noOp) {
 
     @Override
     public boolean isTranslogSyncNeeded() {
-        return false;
+        return translogManager.isTranslogSyncNeeded();
     }
 
     @Override
-    public boolean ensureTranslogSynced(Stream<Translog.Location> locations) {
-        return false;
+    public boolean ensureTranslogSynced(Stream<Translog.Location> locations) throws IOException {
+        return translogManager.ensureTranslogSynced(locations);
     }
 
     @Override
-    public void syncTranslog() {}
+    public void syncTranslog() throws IOException {
+        translogManager.syncTranslog();
+    }
 
     @Override
     public Closeable acquireHistoryRetentionLock() {
@@ -335,6 +385,20 @@ public Translog.Snapshot newChangesSnapshot(
         return newEmptySnapshot();
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link Engine#newChangesSnapshot(String, long, long, boolean, boolean)} instead
+     */
+    @Deprecated
+    @Override
+    public Translog.Snapshot newChangesSnapshotFromTranslogFile(String source, long fromSeqNo, long toSeqNo, boolean requiredFullRange)
+        throws IOException {
+        return newEmptySnapshot();
+    }
+
     @Override
     public int countNumberOfHistoryOperations(String source, long fromSeqNo, long toSeqNo) throws IOException {
         try (Translog.Snapshot snapshot = newChangesSnapshot(source, fromSeqNo, toSeqNo, false, true)) {
@@ -359,7 +423,7 @@ public TranslogStats getTranslogStats() {
 
     @Override
     public Translog.Location getTranslogLastWriteLocation() {
-        return new Translog.Location(0, 0, 0);
+        return translogManager.getTranslogLastWriteLocation();
     }
 
     @Override
@@ -367,6 +431,12 @@ public long getPersistedLocalCheckpoint() {
         return seqNoStats.getLocalCheckpoint();
     }
 
+    public long getProcessedLocalCheckpoint() {
+        // the read-only engine does not process checkpoints, so its
+        // processed checkpoint is identical to its persisted one.
+        return getPersistedLocalCheckpoint();
+    }
+
     @Override
     public SeqNoStats getSeqNoStats(long globalCheckpoint) {
         return new SeqNoStats(seqNoStats.getMaxSeqNo(), seqNoStats.getLocalCheckpoint(), globalCheckpoint);
@@ -442,15 +512,19 @@ public void activateThrottling() {}
     public void deactivateThrottling() {}
 
     @Override
-    public void trimUnreferencedTranslogFiles() {}
+    public void trimUnreferencedTranslogFiles() {
+        translogManager.trimUnreferencedTranslogFiles();
+    }
 
     @Override
     public boolean shouldRollTranslogGeneration() {
-        return false;
+        return translogManager.shouldRollTranslogGeneration();
     }
 
     @Override
-    public void rollTranslogGeneration() {}
+    public void rollTranslogGeneration() {
+        translogManager.rollTranslogGeneration();
+    }
 
     @Override
     public int restoreLocalHistoryFromTranslog(TranslogRecoveryRunner translogRecoveryRunner) {
@@ -476,10 +550,14 @@ public Engine recoverFromTranslog(final TranslogRecoveryRunner translogRecoveryR
     }
 
     @Override
-    public void skipTranslogRecovery() {}
+    public void skipTranslogRecovery() {
+        translogManager.skipTranslogRecovery();
+    }
 
     @Override
-    public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) {}
+    public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) {
+        translogManager.trimOperationsFromTranslog(belowTerm, aboveSeqNo);
+    }
 
     @Override
     public void maybePruneDeletes() {}
diff --git a/server/src/main/java/org/opensearch/index/engine/RecoveryEngineException.java b/server/src/main/java/org/opensearch/index/engine/RecoveryEngineException.java
index b473523ec2c4e..9cc0eb59e95df 100644
--- a/server/src/main/java/org/opensearch/index/engine/RecoveryEngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/RecoveryEngineException.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is a problem during recovery
+ */
 public class RecoveryEngineException extends EngineException {
 
     private final int phase;
diff --git a/server/src/main/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicy.java b/server/src/main/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicy.java
index 0a885f23629e6..493ccbb69a244 100644
--- a/server/src/main/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicy.java
+++ b/server/src/main/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicy.java
@@ -61,6 +61,11 @@
 import java.util.Objects;
 import java.util.function.Supplier;
 
+/**
+ * Merge Policy that prunes the recovery source
+ *
+ * @opensearch.internal
+ */
 final class RecoverySourcePruneMergePolicy extends OneMergeWrappingMergePolicy {
     RecoverySourcePruneMergePolicy(String recoverySourceField, Supplier<Query> retainSourceQuerySupplier, MergePolicy in) {
         super(in, toWrap -> new OneMerge(toWrap.segments) {
@@ -95,6 +100,11 @@ private static CodecReader wrapReader(String recoverySourceField, CodecReader re
         }
     }
 
+    /**
+     * A codec reader that prunes the source using a filter
+     *
+     * @opensearch.internal
+     */
     private static class SourcePruningFilterCodecReader extends FilterCodecReader {
         private final BitSet recoverySourceToKeep;
         private final String recoverySourceField;
@@ -161,6 +171,11 @@ public CacheHelper getReaderCacheHelper() {
             return null;
         }
 
+        /**
+         * A producer of filtered doc vlaues
+         *
+         * @opensearch.internal
+         */
         private static class FilterDocValuesProducer extends DocValuesProducer {
             private final DocValuesProducer in;
 
@@ -204,6 +219,11 @@ public void close() throws IOException {
             }
         }
 
+        /**
+         * A fields reader that provides a filtered stored field
+         *
+         * @opensearch.internal
+         */
         private abstract static class FilterStoredFieldsReader extends StoredFieldsReader {
 
             protected final StoredFieldsReader in;
@@ -218,8 +238,8 @@ public void close() throws IOException {
             }
 
             @Override
-            public void visitDocument(int docID, StoredFieldVisitor visitor) throws IOException {
-                in.visitDocument(docID, visitor);
+            public void document(int docID, StoredFieldVisitor visitor) throws IOException {
+                in.document(docID, visitor);
             }
 
             @Override
@@ -231,6 +251,11 @@ public void checkIntegrity() throws IOException {
             }
         }
 
+        /**
+         * A reader of pruned stored fields
+         *
+         * @opensearch.internal
+         */
         private static class RecoverySourcePruningStoredFieldsReader extends FilterStoredFieldsReader {
 
             private final BitSet recoverySourceToKeep;
@@ -243,11 +268,11 @@ private static class RecoverySourcePruningStoredFieldsReader extends FilterStore
             }
 
             @Override
-            public void visitDocument(int docID, StoredFieldVisitor visitor) throws IOException {
+            public void document(int docID, StoredFieldVisitor visitor) throws IOException {
                 if (recoverySourceToKeep != null && recoverySourceToKeep.get(docID)) {
-                    super.visitDocument(docID, visitor);
+                    super.document(docID, visitor);
                 } else {
-                    super.visitDocument(docID, new FilterStoredFieldVisitor(visitor) {
+                    super.document(docID, new FilterStoredFieldVisitor(visitor) {
                         @Override
                         public Status needsField(FieldInfo fieldInfo) throws IOException {
                             if (recoverySourceField.equals(fieldInfo.name)) {
@@ -268,9 +293,13 @@ public StoredFieldsReader getMergeInstance() {
             public StoredFieldsReader clone() {
                 return new RecoverySourcePruningStoredFieldsReader(in.clone(), recoverySourceToKeep, recoverySourceField);
             }
-
         }
 
+        /**
+         * A visitor pattern for filtered stored fields
+         *
+         * @opensearch.internal
+         */
         private static class FilterStoredFieldVisitor extends StoredFieldVisitor {
             private final StoredFieldVisitor visitor;
 
diff --git a/server/src/main/java/org/opensearch/index/engine/RefreshFailedEngineException.java b/server/src/main/java/org/opensearch/index/engine/RefreshFailedEngineException.java
index 0f07e0e6199b7..35872bb0a1fba 100644
--- a/server/src/main/java/org/opensearch/index/engine/RefreshFailedEngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/RefreshFailedEngineException.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if refresh fails
+ *
+ * @opensearch.internal
+ */
 public class RefreshFailedEngineException extends EngineException {
 
     public RefreshFailedEngineException(ShardId shardId, Throwable t) {
diff --git a/server/src/main/java/org/opensearch/index/engine/ReplicaFileTracker.java b/server/src/main/java/org/opensearch/index/engine/ReplicaFileTracker.java
new file mode 100644
index 0000000000000..2e8bd6409c2f6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/ReplicaFileTracker.java
@@ -0,0 +1,92 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.BiConsumer;
+
+/**
+ * This class is heavily influenced by Lucene's ReplicaFileDeleter class used to keep track of
+ * segment files that should be preserved on replicas between replication events.
+ *
+ * https://github.com/apache/lucene/blob/main/lucene/replicator/src/java/org/apache/lucene/replicator/nrt/ReplicaFileDeleter.java
+ *
+ * @opensearch.internal
+ */
+final class ReplicaFileTracker {
+
+    public static final Logger logger = LogManager.getLogger(ReplicaFileTracker.class);
+    private final Map<String, Integer> refCounts = new HashMap<>();
+    private final BiConsumer<String, String> fileDeleter;
+    private final Set<String> EXCLUDE_FILES = Set.of("write.lock");
+
+    public ReplicaFileTracker(BiConsumer<String, String> fileDeleter) {
+        this.fileDeleter = fileDeleter;
+    }
+
+    public synchronized void incRef(Collection<String> fileNames) {
+        for (String fileName : fileNames) {
+            refCounts.merge(fileName, 1, Integer::sum);
+        }
+    }
+
+    public synchronized int refCount(String file) {
+        return Optional.ofNullable(refCounts.get(file)).orElse(0);
+    }
+
+    public synchronized void decRef(Collection<String> fileNames) {
+        Set<String> toDelete = new HashSet<>();
+        for (String fileName : fileNames) {
+            Integer curCount = refCounts.get(fileName);
+            assert curCount != null : "fileName=" + fileName;
+            assert curCount > 0;
+            if (curCount == 1) {
+                refCounts.remove(fileName);
+                toDelete.add(fileName);
+            } else {
+                refCounts.put(fileName, curCount - 1);
+            }
+        }
+        if (toDelete.isEmpty() == false) {
+            delete(toDelete);
+        }
+    }
+
+    public void deleteUnreferencedFiles(String... toDelete) {
+        for (String file : toDelete) {
+            if (canDelete(file)) {
+                delete(file);
+            }
+        }
+    }
+
+    private synchronized void delete(Collection<String> toDelete) {
+        for (String fileName : toDelete) {
+            delete(fileName);
+        }
+    }
+
+    private synchronized void delete(String fileName) {
+        assert canDelete(fileName);
+        fileDeleter.accept("delete unreferenced", fileName);
+    }
+
+    private synchronized boolean canDelete(String fileName) {
+        return EXCLUDE_FILES.contains(fileName) == false && refCounts.containsKey(fileName) == false;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/engine/SafeCommitInfo.java b/server/src/main/java/org/opensearch/index/engine/SafeCommitInfo.java
index 8c76f735035cb..fcf1cb186269c 100644
--- a/server/src/main/java/org/opensearch/index/engine/SafeCommitInfo.java
+++ b/server/src/main/java/org/opensearch/index/engine/SafeCommitInfo.java
@@ -35,6 +35,8 @@
 
 /**
  * Information about the safe commit, for making decisions about recoveries.
+ *
+ * @opensearch.internal
  */
 public class SafeCommitInfo {
 
diff --git a/server/src/main/java/org/opensearch/index/engine/Segment.java b/server/src/main/java/org/opensearch/index/engine/Segment.java
index 4874d0a30196f..d83ba70c8a61a 100644
--- a/server/src/main/java/org/opensearch/index/engine/Segment.java
+++ b/server/src/main/java/org/opensearch/index/engine/Segment.java
@@ -34,24 +34,29 @@
 
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
-import org.apache.lucene.search.SortedSetSortField;
+import org.apache.lucene.search.SortedNumericSelector;
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSelector;
-import org.apache.lucene.search.SortedNumericSelector;
+import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.util.Accountable;
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * A segment in the engine
+ *
+ * @opensearch.internal
+ */
 public class Segment implements Writeable {
 
     private String name;
diff --git a/server/src/main/java/org/opensearch/index/engine/SegmentsStats.java b/server/src/main/java/org/opensearch/index/engine/SegmentsStats.java
index 880091c192034..f4fd2490c7abe 100644
--- a/server/src/main/java/org/opensearch/index/engine/SegmentsStats.java
+++ b/server/src/main/java/org/opensearch/index/engine/SegmentsStats.java
@@ -32,18 +32,26 @@
 
 package org.opensearch.index.engine;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.Version;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.ReplicationStats;
+import org.opensearch.index.remote.RemoteSegmentStats;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
+/**
+ * Tracker for segment stats
+ *
+ * @opensearch.internal
+ */
 public class SegmentsStats implements Writeable, ToXContentFragment {
 
     private long count;
@@ -51,39 +59,48 @@ public class SegmentsStats implements Writeable, ToXContentFragment {
     private long versionMapMemoryInBytes;
     private long maxUnsafeAutoIdTimestamp = Long.MIN_VALUE;
     private long bitsetMemoryInBytes;
-    private ImmutableOpenMap<String, Long> fileSizes = ImmutableOpenMap.of();
-
+    private final Map<String, Long> fileSizes;
+    private final RemoteSegmentStats remoteSegmentStats;
     private static final ByteSizeValue ZERO_BYTE_SIZE_VALUE = new ByteSizeValue(0L);
 
+    /**
+     * Segment replication statistics.
+     */
+    private final ReplicationStats replicationStats;
+
     /*
      * A map to provide a best-effort approach describing Lucene index files.
      *
      * Ideally this should be in sync to what the current version of Lucene is using, but it's harmless to leave extensions out,
      * they'll just miss a proper description in the stats
      */
-    private static final ImmutableOpenMap<String, String> FILE_DESCRIPTIONS = ImmutableOpenMap.<String, String>builder()
-        .fPut("si", "Segment Info")
-        .fPut("fnm", "Fields")
-        .fPut("fdx", "Field Index")
-        .fPut("fdt", "Field Data")
-        .fPut("tim", "Term Dictionary")
-        .fPut("tip", "Term Index")
-        .fPut("doc", "Frequencies")
-        .fPut("pos", "Positions")
-        .fPut("pay", "Payloads")
-        .fPut("nvd", "Norms")
-        .fPut("nvm", "Norms")
-        .fPut("dii", "Points")
-        .fPut("dim", "Points")
-        .fPut("dvd", "DocValues")
-        .fPut("dvm", "DocValues")
-        .fPut("tvx", "Term Vector Index")
-        .fPut("tvd", "Term Vector Documents")
-        .fPut("tvf", "Term Vector Fields")
-        .fPut("liv", "Live Documents")
-        .build();
-
-    public SegmentsStats() {}
+    private static final Map<String, String> FILE_DESCRIPTIONS = Map.ofEntries(
+        Map.entry("si", "Segment Info"),
+        Map.entry("fnm", "Fields"),
+        Map.entry("fdx", "Field Index"),
+        Map.entry("fdt", "Field Data"),
+        Map.entry("tim", "Term Dictionary"),
+        Map.entry("tip", "Term Index"),
+        Map.entry("doc", "Frequencies"),
+        Map.entry("pos", "Positions"),
+        Map.entry("pay", "Payloads"),
+        Map.entry("nvd", "Norms"),
+        Map.entry("nvm", "Norms"),
+        Map.entry("dii", "Points"),
+        Map.entry("dim", "Points"),
+        Map.entry("dvd", "DocValues"),
+        Map.entry("dvm", "DocValues"),
+        Map.entry("tvx", "Term Vector Index"),
+        Map.entry("tvd", "Term Vector Documents"),
+        Map.entry("tvf", "Term Vector Fields"),
+        Map.entry("liv", "Live Documents")
+    );
+
+    public SegmentsStats() {
+        fileSizes = new HashMap<>();
+        remoteSegmentStats = new RemoteSegmentStats();
+        replicationStats = new ReplicationStats();
+    }
 
     public SegmentsStats(StreamInput in) throws IOException {
         count = in.readVLong();
@@ -102,15 +119,14 @@ public SegmentsStats(StreamInput in) throws IOException {
         versionMapMemoryInBytes = in.readLong();
         bitsetMemoryInBytes = in.readLong();
         maxUnsafeAutoIdTimestamp = in.readLong();
-
-        int size = in.readVInt();
-        ImmutableOpenMap.Builder<String, Long> map = ImmutableOpenMap.builder(size);
-        for (int i = 0; i < size; i++) {
-            String key = in.readString();
-            Long value = in.readLong();
-            map.put(key, value);
+        fileSizes = in.readMap(StreamInput::readString, StreamInput::readLong);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            remoteSegmentStats = in.readOptionalWriteable(RemoteSegmentStats::new);
+            replicationStats = in.readOptionalWriteable(ReplicationStats::new);
+        } else {
+            remoteSegmentStats = new RemoteSegmentStats();
+            replicationStats = new ReplicationStats();
         }
-        fileSizes = map.build();
     }
 
     public void add(long count) {
@@ -133,19 +149,20 @@ public void addBitsetMemoryInBytes(long bitsetMemoryInBytes) {
         this.bitsetMemoryInBytes += bitsetMemoryInBytes;
     }
 
-    public void addFileSizes(ImmutableOpenMap<String, Long> fileSizes) {
-        ImmutableOpenMap.Builder<String, Long> map = ImmutableOpenMap.builder(this.fileSizes);
+    public void addRemoteSegmentStats(RemoteSegmentStats remoteSegmentStats) {
+        this.remoteSegmentStats.add(remoteSegmentStats);
+    }
 
-        for (ObjectObjectCursor<String, Long> entry : fileSizes) {
-            if (map.containsKey(entry.key)) {
-                Long oldValue = map.get(entry.key);
-                map.put(entry.key, oldValue + entry.value);
-            } else {
-                map.put(entry.key, entry.value);
-            }
-        }
+    public void addReplicationStats(ReplicationStats replicationStats) {
+        this.replicationStats.add(replicationStats);
+    }
 
-        this.fileSizes = map.build();
+    public void addFileSizes(final Map<String, Long> newFileSizes) {
+        newFileSizes.forEach((k, v) -> this.fileSizes.merge(k, v, (a, b) -> {
+            assert a != null;
+            assert b != null;
+            return Math.addExact(a, b);
+        }));
     }
 
     public void add(SegmentsStats mergeStats) {
@@ -158,6 +175,8 @@ public void add(SegmentsStats mergeStats) {
         addVersionMapMemoryInBytes(mergeStats.versionMapMemoryInBytes);
         addBitsetMemoryInBytes(mergeStats.bitsetMemoryInBytes);
         addFileSizes(mergeStats.fileSizes);
+        addRemoteSegmentStats(mergeStats.remoteSegmentStats);
+        addReplicationStats(mergeStats.replicationStats);
     }
 
     /**
@@ -200,8 +219,18 @@ public ByteSizeValue getBitsetMemory() {
         return new ByteSizeValue(bitsetMemoryInBytes);
     }
 
-    public ImmutableOpenMap<String, Long> getFileSizes() {
-        return fileSizes;
+    /** Returns mapping of file names to their size (only used in tests) */
+    public Map<String, Long> getFileSizes() {
+        return Collections.unmodifiableMap(this.fileSizes);
+    }
+
+    /** Returns remote_store based stats **/
+    public RemoteSegmentStats getRemoteSegmentStats() {
+        return remoteSegmentStats;
+    }
+
+    public ReplicationStats getReplicationStats() {
+        return replicationStats;
     }
 
     /**
@@ -227,11 +256,13 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.humanReadableField(Fields.VERSION_MAP_MEMORY_IN_BYTES, Fields.VERSION_MAP_MEMORY, getVersionMapMemory());
         builder.humanReadableField(Fields.FIXED_BIT_SET_MEMORY_IN_BYTES, Fields.FIXED_BIT_SET, getBitsetMemory());
         builder.field(Fields.MAX_UNSAFE_AUTO_ID_TIMESTAMP, maxUnsafeAutoIdTimestamp);
+        remoteSegmentStats.toXContent(builder, params);
+        replicationStats.toXContent(builder, params);
         builder.startObject(Fields.FILE_SIZES);
-        for (ObjectObjectCursor<String, Long> entry : fileSizes) {
-            builder.startObject(entry.key);
-            builder.humanReadableField(Fields.SIZE_IN_BYTES, Fields.SIZE, new ByteSizeValue(entry.value));
-            builder.field(Fields.DESCRIPTION, FILE_DESCRIPTIONS.getOrDefault(entry.key, "Others"));
+        for (Map.Entry<String, Long> entry : fileSizes.entrySet()) {
+            builder.startObject(entry.getKey());
+            builder.humanReadableField(Fields.SIZE_IN_BYTES, Fields.SIZE, new ByteSizeValue(entry.getValue()));
+            builder.field(Fields.DESCRIPTION, FILE_DESCRIPTIONS.getOrDefault(entry.getKey(), "Others"));
             builder.endObject();
         }
         builder.endObject();
@@ -239,6 +270,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for segment statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String SEGMENTS = "segments";
         static final String COUNT = "count";
@@ -287,16 +323,15 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeLong(versionMapMemoryInBytes);
         out.writeLong(bitsetMemoryInBytes);
         out.writeLong(maxUnsafeAutoIdTimestamp);
-
-        out.writeVInt(fileSizes.size());
-        for (ObjectObjectCursor<String, Long> entry : fileSizes) {
-            out.writeString(entry.key);
-            out.writeLong(entry.value);
+        out.writeMap(this.fileSizes, StreamOutput::writeString, StreamOutput::writeLong);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalWriteable(remoteSegmentStats);
+            out.writeOptionalWriteable(replicationStats);
         }
     }
 
     public void clearFileSizes() {
-        fileSizes = ImmutableOpenMap.of();
+        fileSizes.clear();
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/index/engine/SnapshotFailedEngineException.java b/server/src/main/java/org/opensearch/index/engine/SnapshotFailedEngineException.java
index 77c05f62c3c26..ef5829a481366 100644
--- a/server/src/main/java/org/opensearch/index/engine/SnapshotFailedEngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/SnapshotFailedEngineException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if snapshot fails the engine
+ *
+ * @opensearch.internal
+ */
 public class SnapshotFailedEngineException extends EngineException {
 
     public SnapshotFailedEngineException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/index/engine/SoftDeletesPolicy.java b/server/src/main/java/org/opensearch/index/engine/SoftDeletesPolicy.java
index 72f44db2fa138..eef73f1d49a8e 100644
--- a/server/src/main/java/org/opensearch/index/engine/SoftDeletesPolicy.java
+++ b/server/src/main/java/org/opensearch/index/engine/SoftDeletesPolicy.java
@@ -48,6 +48,8 @@
 
 /**
  * A policy that controls how many soft-deleted documents should be retained for peer-recovery and querying history changes purpose.
+ *
+ * @opensearch.internal
  */
 final class SoftDeletesPolicy {
     private final LongSupplier globalCheckpointSupplier;
diff --git a/server/src/main/java/org/opensearch/index/engine/TranslogLeafReader.java b/server/src/main/java/org/opensearch/index/engine/TranslogLeafReader.java
index 09a670237a8a5..6aacb6c1cbedf 100644
--- a/server/src/main/java/org/opensearch/index/engine/TranslogLeafReader.java
+++ b/server/src/main/java/org/opensearch/index/engine/TranslogLeafReader.java
@@ -32,10 +32,12 @@
 package org.opensearch.index.engine;
 
 import org.apache.lucene.index.BinaryDocValues;
+import org.apache.lucene.index.ByteVectorValues;
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.Fields;
+import org.apache.lucene.index.FloatVectorValues;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.LeafMetaData;
 import org.apache.lucene.index.LeafReader;
@@ -45,9 +47,11 @@
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.index.StoredFieldVisitor;
+import org.apache.lucene.index.StoredFields;
+import org.apache.lucene.index.TermVectors;
 import org.apache.lucene.index.Terms;
+import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.index.VectorSimilarityFunction;
-import org.apache.lucene.index.VectorValues;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
@@ -64,6 +68,8 @@
 
 /**
  * Internal class that mocks a single doc read from the transaction log as a leaf reader.
+ *
+ * @opensearch.internal
  */
 public final class TranslogLeafReader extends LeafReader {
 
@@ -82,6 +88,7 @@ public final class TranslogLeafReader extends LeafReader {
         0,
         0,
         0,
+        VectorEncoding.FLOAT32,
         VectorSimilarityFunction.EUCLIDEAN,
         false
     );
@@ -99,6 +106,7 @@ public final class TranslogLeafReader extends LeafReader {
         0,
         0,
         0,
+        VectorEncoding.FLOAT32,
         VectorSimilarityFunction.EUCLIDEAN,
         false
     );
@@ -116,6 +124,7 @@ public final class TranslogLeafReader extends LeafReader {
         0,
         0,
         0,
+        VectorEncoding.FLOAT32,
         VectorSimilarityFunction.EUCLIDEAN,
         false
     );
@@ -195,6 +204,11 @@ public Fields getTermVectors(int docID) {
         throw new UnsupportedOperationException();
     }
 
+    @Override
+    public TermVectors termVectors() throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public int numDocs() {
         return 1;
@@ -207,23 +221,33 @@ public int maxDoc() {
 
     @Override
     public void document(int docID, StoredFieldVisitor visitor) throws IOException {
-        if (docID != 0) {
-            throw new IllegalArgumentException("no such doc ID " + docID);
-        }
-        if (visitor.needsField(FAKE_SOURCE_FIELD) == StoredFieldVisitor.Status.YES) {
-            assert operation.source().toBytesRef().offset == 0;
-            assert operation.source().toBytesRef().length == operation.source().toBytesRef().bytes.length;
-            visitor.binaryField(FAKE_SOURCE_FIELD, operation.source().toBytesRef().bytes);
-        }
-        if (operation.routing() != null && visitor.needsField(FAKE_ROUTING_FIELD) == StoredFieldVisitor.Status.YES) {
-            visitor.stringField(FAKE_ROUTING_FIELD, operation.routing());
-        }
-        if (visitor.needsField(FAKE_ID_FIELD) == StoredFieldVisitor.Status.YES) {
-            BytesRef bytesRef = Uid.encodeId(operation.id());
-            final byte[] id = new byte[bytesRef.length];
-            System.arraycopy(bytesRef.bytes, bytesRef.offset, id, 0, bytesRef.length);
-            visitor.binaryField(FAKE_ID_FIELD, id);
-        }
+        storedFields().document(docID, visitor);
+    }
+
+    @Override
+    public StoredFields storedFields() throws IOException {
+        return new StoredFields() {
+            @Override
+            public void document(int docID, StoredFieldVisitor visitor) throws IOException {
+                if (docID != 0) {
+                    throw new IllegalArgumentException("no such doc ID " + docID);
+                }
+                if (visitor.needsField(FAKE_SOURCE_FIELD) == StoredFieldVisitor.Status.YES) {
+                    assert operation.source().toBytesRef().offset == 0;
+                    assert operation.source().toBytesRef().length == operation.source().toBytesRef().bytes.length;
+                    visitor.binaryField(FAKE_SOURCE_FIELD, operation.source().toBytesRef().bytes);
+                }
+                if (operation.routing() != null && visitor.needsField(FAKE_ROUTING_FIELD) == StoredFieldVisitor.Status.YES) {
+                    visitor.stringField(FAKE_ROUTING_FIELD, operation.routing());
+                }
+                if (visitor.needsField(FAKE_ID_FIELD) == StoredFieldVisitor.Status.YES) {
+                    BytesRef bytesRef = Uid.encodeId(operation.id());
+                    final byte[] id = new byte[bytesRef.length];
+                    System.arraycopy(bytesRef.bytes, bytesRef.offset, id, 0, bytesRef.length);
+                    visitor.binaryField(FAKE_ID_FIELD, id);
+                }
+            }
+        };
     }
 
     @Override
@@ -237,8 +261,18 @@ public CacheHelper getReaderCacheHelper() {
     }
 
     @Override
-    public VectorValues getVectorValues(String field) throws IOException {
-        return getVectorValues(field);
+    public FloatVectorValues getFloatVectorValues(String field) throws IOException {
+        return getFloatVectorValues(field);
+    }
+
+    @Override
+    public ByteVectorValues getByteVectorValues(String field) throws IOException {
+        return getByteVectorValues(field);
+    }
+
+    @Override
+    public TopDocs searchNearestVectors(String field, byte[] target, int k, Bits acceptDocs, int visitedLimit) throws IOException {
+        throw new UnsupportedOperationException();
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/engine/VersionConflictEngineException.java b/server/src/main/java/org/opensearch/index/engine/VersionConflictEngineException.java
index c473f3db6dbf7..7804b8985e94d 100644
--- a/server/src/main/java/org/opensearch/index/engine/VersionConflictEngineException.java
+++ b/server/src/main/java/org/opensearch/index/engine/VersionConflictEngineException.java
@@ -31,13 +31,18 @@
 
 package org.opensearch.index.engine;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is a version conflict
+ *
+ * @opensearch.internal
+ */
 public class VersionConflictEngineException extends EngineException {
 
     public VersionConflictEngineException(ShardId shardId, Engine.Operation op, long currentVersion, boolean deleted) {
diff --git a/server/src/main/java/org/opensearch/index/engine/VersionValue.java b/server/src/main/java/org/opensearch/index/engine/VersionValue.java
index 99f9a83a9902c..a463137d13912 100644
--- a/server/src/main/java/org/opensearch/index/engine/VersionValue.java
+++ b/server/src/main/java/org/opensearch/index/engine/VersionValue.java
@@ -40,6 +40,11 @@
 import java.util.Collection;
 import java.util.Collections;
 
+/**
+ * Represents the version of a document in the index
+ *
+ * @opensearch.internal
+ */
 abstract class VersionValue implements Accountable {
 
     private static final long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(VersionValue.class);
diff --git a/server/src/main/java/org/opensearch/index/engine/package-info.java b/server/src/main/java/org/opensearch/index/engine/package-info.java
new file mode 100644
index 0000000000000..283ef24f04d50
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/engine/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing engine operations */
+package org.opensearch.index.engine;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractBinaryDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractBinaryDocValues.java
index 6ce3277e3b344..b07033ed265b0 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractBinaryDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractBinaryDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #binaryValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractBinaryDocValues extends BinaryDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractNumericDocValues.java
index 1bb016ef6546d..a2a70e280187a 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractNumericDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #longValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractNumericDocValues extends NumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedDocValues.java
index ff46b6feed465..b72ba837808a9 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #ordValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractSortedDocValues extends SortedDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedNumericDocValues.java
index f911dc8b990bd..6379533069bc6 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedNumericDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #docValueCount()} and {@link #nextValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractSortedNumericDocValues extends SortedNumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedSetDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedSetDocValues.java
index 42a3b440feaef..c7312f2074b9e 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedSetDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortedSetDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #getValueCount()} and {@link #nextOrd()} and {@link #lookupOrd(long)}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractSortedSetDocValues extends SortedSetDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortingNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortingNumericDocValues.java
index 6d93df9f17452..f37dcac740f6a 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/AbstractSortingNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/AbstractSortingNumericDocValues.java
@@ -42,6 +42,8 @@
  * {@link DocIdSetIterator} APIs. This impl is safe to use for sorting and
  * aggregations, which only use {@link #advanceExact(int)} and
  * {@link #docValueCount()} and {@link #nextValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractSortingNumericDocValues extends SortingNumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/DocValueBits.java b/server/src/main/java/org/opensearch/index/fielddata/DocValueBits.java
index b94de0d529f96..18fa26bd10623 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/DocValueBits.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/DocValueBits.java
@@ -34,6 +34,11 @@
 
 import java.io.IOException;
 
+/**
+ * Base class for doc value bit sets
+ *
+ * @opensearch.internal
+ */
 public abstract class DocValueBits {
 
     /**
diff --git a/server/src/main/java/org/opensearch/index/fielddata/FieldData.java b/server/src/main/java/org/opensearch/index/fielddata/FieldData.java
index 93ae689a51f7b..e09de53dc05f7 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/FieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/FieldData.java
@@ -38,14 +38,18 @@
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.geo.GeoPoint;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * Utility methods, similar to Lucene's {@link DocValues}.
+ *
+ * @opensearch.internal
  */
 public enum FieldData {
     ;
@@ -97,12 +101,19 @@ public GeoPoint geoPointValue() {
     }
 
     /**
-     * Return a {@link SortedNumericDoubleValues} that doesn't contain any value.
+     * Return a {@link MultiGeoPointValues} that doesn't contain any value.
      */
     public static MultiGeoPointValues emptyMultiGeoPoints() {
         return singleton(emptyGeoPoint());
     }
 
+    /**
+     * Return a {@link GeoShapeValue} that doesn't contain any value.
+     */
+    public static GeoShapeValue emptyGeoShape() {
+        return new GeoShapeValue.EmptyGeoShapeValue();
+    }
+
     /**
      * Returns a {@link DocValueBits} representing all documents from <code>values</code> that have a value.
      */
@@ -141,6 +152,19 @@ public boolean advanceExact(int doc) throws IOException {
         };
     }
 
+    /**
+     * Returns a {@link DocValueBits} representing all documents from <code>shapeValues</code> that have
+     * a value.
+     */
+    public static DocValueBits docsWithValue(final GeoShapeValue shapeValues) {
+        return new DocValueBits() {
+            @Override
+            public boolean advanceExact(int doc) throws IOException {
+                return shapeValues.advanceExact(doc);
+            }
+        };
+    }
+
     /**
      * Returns a {@link DocValueBits} representing all documents from <code>doubleValues</code> that have a value.
      */
@@ -215,6 +239,30 @@ public static SortedNumericDoubleValues sortableLongBitsToDoubles(SortedNumericD
         }
     }
 
+    /**
+     * Given a {@link SortedNumericDocValues}, return a {@link SortedNumericDoubleValues}
+     * instance that will translate unsigned long values to doubles using
+     * {@link Numbers#toUnsignedBigInteger(long)}.
+     */
+    public static SortedNumericDoubleValues unsignedLongToDoubles(SortedNumericDocValues values) {
+        final NumericDocValues singleton = DocValues.unwrapSingleton(values);
+        if (singleton != null) {
+            final NumericDoubleValues doubles;
+            if (singleton instanceof SortableLongBitsNumericDocValues) {
+                doubles = ((SortableLongBitsNumericDocValues) singleton).getDoubleValues();
+            } else {
+                doubles = new UnsignedLongToNumericDoubleValues(singleton);
+            }
+            return singleton(doubles);
+        } else {
+            if (values instanceof SortableLongBitsSortedNumericDocValues) {
+                return ((SortableLongBitsSortedNumericDocValues) values).getDoubleValues();
+            } else {
+                return new UnsignedLongToSortedNumericDoubleValues(values);
+            }
+        }
+    }
+
     /**
      * Wrap the provided {@link SortedNumericDocValues} instance to cast all values to doubles.
      */
@@ -325,6 +373,27 @@ public void get(List<CharSequence> list) throws IOException {
         });
     }
 
+    /**
+     * Return a {@link String} representation of the provided values treating them as unsigned. That is
+     * typically used for scripts or for the `map` execution mode of terms aggs.
+     * NOTE: this is very slow!
+     */
+    public static SortedBinaryDocValues toUnsignedString(final SortedNumericDocValues values) {
+        return toString(new ToStringValues() {
+            @Override
+            public boolean advanceExact(int doc) throws IOException {
+                return values.advanceExact(doc);
+            }
+
+            @Override
+            public void get(List<CharSequence> list) throws IOException {
+                for (int i = 0, count = values.docValueCount(); i < count; ++i) {
+                    list.add(Long.toUnsignedString(values.nextValue()));
+                }
+            }
+        });
+    }
+
     /**
      * Return a {@link String} representation of the provided values. That is
      * typically used for scripts or for the `map` execution mode of terms aggs.
@@ -406,6 +475,31 @@ public void get(List<CharSequence> list) throws IOException {
         });
     }
 
+    /**
+     * Return a {@link String} representation of the provided values. That is
+     * typically used for scripts or for the `map` execution mode of terms aggs.
+     * NOTE: this is very slow!
+     */
+    public static SortedBinaryDocValues toString(final GeoShapeValue geoShapeValue) {
+        return toString(new ToStringValues() {
+
+            /**
+             * Advance this instance to the given document id
+             * @return true if there is a value for this document
+             */
+            @Override
+            public boolean advanceExact(int doc) throws IOException {
+                return geoShapeValue.advanceExact(doc);
+            }
+
+            /** Fill the list of charsequences with the list of values for the current document. */
+            @Override
+            public void get(List<CharSequence> list) throws IOException {
+                list.add(geoShapeValue.nextValue().toString());
+            }
+        });
+    }
+
     private static SortedBinaryDocValues toString(final ToStringValues toStringValues) {
         return new SortingBinaryDocValues() {
 
@@ -444,6 +538,11 @@ private interface ToStringValues {
 
     }
 
+    /**
+     * Values casted as a double type
+     *
+     * @opensearch.internal
+     */
     private static class DoubleCastedValues extends NumericDoubleValues {
 
         private final NumericDocValues values;
@@ -464,6 +563,11 @@ public boolean advanceExact(int doc) throws IOException {
 
     }
 
+    /**
+     * Sorted values casted as a double type
+     *
+     * @opensearch.internal
+     */
     private static class SortedDoubleCastedValues extends SortedNumericDoubleValues {
 
         private final SortedNumericDocValues values;
@@ -489,6 +593,11 @@ public int docValueCount() {
 
     }
 
+    /**
+     * Values casted as a long type
+     *
+     * @opensearch.internal
+     */
     private static class LongCastedValues extends AbstractNumericDocValues {
 
         private final NumericDoubleValues values;
@@ -515,6 +624,11 @@ public int docID() {
         }
     }
 
+    /**
+     * Sorted values casted as a long type
+     *
+     * @opensearch.internal
+     */
     private static class SortedLongCastedValues extends AbstractSortedNumericDocValues {
 
         private final SortedNumericDoubleValues values;
@@ -572,6 +686,38 @@ public long longValue() throws IOException {
         };
     }
 
+    /**
+     * Return a {@link NumericDocValues} instance that has a value for every
+     * document, returns the same value as {@code values} if there is a value
+     * for the current document and {@code missing} otherwise.
+     */
+    public static NumericDocValues replaceMissing(NumericDocValues values, BigInteger missing) {
+        return new AbstractNumericDocValues() {
+
+            private BigInteger value;
+
+            @Override
+            public int docID() {
+                return values.docID();
+            }
+
+            @Override
+            public boolean advanceExact(int target) throws IOException {
+                if (values.advanceExact(target)) {
+                    value = Numbers.toUnsignedBigInteger(values.longValue());
+                } else {
+                    value = missing;
+                }
+                return true;
+            }
+
+            @Override
+            public long longValue() throws IOException {
+                return value.longValue();
+            }
+        };
+    }
+
     /**
      * Return a {@link NumericDoubleValues} instance that has a value for every
      * document, returns the same value as {@code values} if there is a value
diff --git a/server/src/main/java/org/opensearch/index/fielddata/FieldDataStats.java b/server/src/main/java/org/opensearch/index/fielddata/FieldDataStats.java
index fe27fccd1e3c9..fc7db7d316214 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/FieldDataStats.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/FieldDataStats.java
@@ -34,16 +34,21 @@
 
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Encapsulates heap usage for field data
+ *
+ * @opensearch.internal
+ */
 public class FieldDataStats implements Writeable, ToXContentFragment {
 
     private static final String FIELDDATA = "fielddata";
diff --git a/server/src/main/java/org/opensearch/index/fielddata/GeoPointValues.java b/server/src/main/java/org/opensearch/index/fielddata/GeoPointValues.java
index 98bb9f0f11e74..ce11a015d2d5b 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/GeoPointValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/GeoPointValues.java
@@ -38,6 +38,8 @@
 
 /**
  * Per-document geo-point values.
+ *
+ * @opensearch.internal
  */
 public abstract class GeoPointValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/GeoShapeValue.java b/server/src/main/java/org/opensearch/index/fielddata/GeoShapeValue.java
new file mode 100644
index 0000000000000..5c1d0155c9c56
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/GeoShapeValue.java
@@ -0,0 +1,161 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.document.LatLonShapeDocValuesField;
+import org.apache.lucene.index.BinaryDocValues;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.index.mapper.GeoShapeFieldMapper;
+
+import java.io.IOException;
+
+/**
+ * A stateful lightweight iterator interface to read the stored form of {@link Geometry} aka
+ * {@link LatLonShapeDocValuesField} from Lucene per document. Check {@link GeoShapeFieldMapper} for details how we
+ * converted the {@link Geometry} to {@link LatLonShapeDocValuesField}
+ *
+ * @opensearch.internal
+ */
+public abstract class GeoShapeValue {
+    /**
+     * Creates a new {@link GeoShapeValue} instance
+     */
+    protected GeoShapeValue() {}
+
+    /**
+     * Advance this instance to the given document id
+     *
+     * @return true if there is a value for this document
+     */
+    public abstract boolean advanceExact(int doc) throws IOException;
+
+    /**
+     * Return the next value associated with the current document.
+     *
+     * @return the next value for the current docID set to {@link #advanceExact(int)}.
+     */
+    public abstract GeoShapeDocValue nextValue() throws IOException;
+
+    /**
+     * This is the representation of an EmptyGeoShapeValue
+     */
+    public static class EmptyGeoShapeValue extends GeoShapeValue {
+        /**
+         * Advance this instance to the given document id
+         *
+         * @param doc int
+         * @return true if there is a value for this document
+         */
+        @Override
+        public boolean advanceExact(int doc) throws IOException {
+            return false;
+        }
+
+        /**
+         * Return the next value associated with the current document.
+         *
+         * @return the next value for the current docID set to {@link #advanceExact(int)}.
+         */
+        @Override
+        public GeoShapeDocValue nextValue() throws IOException {
+            throw new UnsupportedOperationException("This empty geoShape value, hence this operation is not supported");
+        }
+    }
+
+    /**
+     * The MissingGeoShapeValue is used when on a particular document the GeoShape field is not present and user has
+     * provided a missing/default GeoShape value in the input which should be used.
+     */
+    public static class MissingGeoShapeValue extends GeoShapeValue {
+
+        private boolean useMissingGeoShapeValue;
+        private final GeoShapeValue valueSourceData;
+        private final Geometry missing;
+
+        private GeoShapeDocValue geoShapeDocValue;
+
+        public MissingGeoShapeValue(final GeoShapeValue valueSourceData, final Geometry missing) {
+            super();
+            this.missing = missing;
+            this.valueSourceData = valueSourceData;
+            this.useMissingGeoShapeValue = false;
+        }
+
+        /**
+         * Advance this instance to the given document id
+         *
+         * @param doc int
+         * @return true if there is a value for this document
+         */
+        @Override
+        public boolean advanceExact(int doc) throws IOException {
+            // If we don't have next value for the doc then set useMissingGeoShapeValue = true
+            useMissingGeoShapeValue = !valueSourceData.advanceExact(doc);
+            // always return true because we want to return a value even if
+            // the document does not have a value
+            return true;
+        }
+
+        /**
+         * Return the next value associated with the current document.
+         *
+         * @return the next value for the current docID set to {@link #advanceExact(int)}.
+         */
+        @Override
+        public GeoShapeDocValue nextValue() throws IOException {
+            if (useMissingGeoShapeValue) {
+                if (geoShapeDocValue == null) {
+                    // keeping geometryDocValue cache so that it can be reused.
+                    geoShapeDocValue = GeoShapeDocValue.createGeometryDocValue(missing);
+                }
+                return geoShapeDocValue;
+            }
+            return valueSourceData.nextValue();
+        }
+    }
+
+    /**
+     * This is the standard implementation of the {@link GeoShapeValue} interface for iterating over the doc values
+     * for a GeoShape field.
+     */
+    public static class StandardGeoShapeValue extends GeoShapeValue {
+
+        private final BinaryDocValues binaryDocValues;
+        private final String fieldName;
+
+        public StandardGeoShapeValue(final BinaryDocValues binaryDocValues, final String fieldName) {
+            this.binaryDocValues = binaryDocValues;
+            this.fieldName = fieldName;
+        }
+
+        /**
+         * Advance this instance to the given document id
+         *
+         * @return true if there is a value for this document
+         */
+        @Override
+        public boolean advanceExact(int doc) throws IOException {
+            return binaryDocValues.advanceExact(doc);
+        }
+
+        /**
+         * Return the next value associated with the current document.
+         *
+         * @return the next value for the current docID set to {@link #advanceExact(int)}.
+         */
+        @Override
+        public GeoShapeDocValue nextValue() throws IOException {
+            final BytesRef bytesRef = binaryDocValues.binaryValue();
+            // Converting the ByteRef to GeometryDocValue.
+            return new GeoShapeDocValue(fieldName, bytesRef);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/HistogramValue.java b/server/src/main/java/org/opensearch/index/fielddata/HistogramValue.java
index 4d3cf4f086429..bb7a89e2e783f 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/HistogramValue.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/HistogramValue.java
@@ -37,6 +37,8 @@
 /**
  * Per-document histogram value. Every value of the histogram consist on
  * a value and a count.
+ *
+ * @opensearch.internal
  */
 public abstract class HistogramValue {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/HistogramValues.java b/server/src/main/java/org/opensearch/index/fielddata/HistogramValues.java
index ed5e9b307f693..001d9fdb7b8eb 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/HistogramValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/HistogramValues.java
@@ -36,6 +36,8 @@
 
 /**
  * Per-segment histogram values.
+ *
+ * @opensearch.internal
  */
 public abstract class HistogramValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldData.java
index deda9081e0448..81d4ce2dd8772 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldData.java
@@ -49,8 +49,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
@@ -63,6 +63,8 @@
 /**
  * Thread-safe utility class that allows to get per-segment values via the
  * {@link #load(LeafReaderContext)} method.
+ *
+ * @opensearch.internal
  */
 public interface IndexFieldData<FD extends LeafFieldData> {
 
@@ -92,6 +94,13 @@ public interface IndexFieldData<FD extends LeafFieldData> {
      */
     SortField sortField(@Nullable Object missingValue, MultiValueMode sortMode, Nested nested, boolean reverse);
 
+    /**
+     * Returns the {@link SortField} to use for index sorting where we widen the sort field type to higher or equal bytes.
+     */
+    default SortField wideSortField(@Nullable Object missingValue, MultiValueMode sortMode, Nested nested, boolean reverse) {
+        return sortField(missingValue, sortMode, nested, reverse);
+    }
+
     /**
      * Build a sort implementation specialized for aggregations.
      */
@@ -106,19 +115,25 @@ BucketedSort newBucketedSort(
         BucketedSort.ExtraData extra
     );
 
-    // we need this extended source we we have custom comparators to reuse our field data
-    // in this case, we need to reduce type that will be used when search results are reduced
-    // on another node (we don't have the custom source them...)
+    /**
+     *  we need this extended source we we have custom comparators to reuse our field data
+     *  in this case, we need to reduce type that will be used when search results are reduced
+     *  on another node (we don't have the custom source them...)
+     *
+     * @opensearch.internal
+     */
     abstract class XFieldComparatorSource extends FieldComparatorSource {
 
         protected final MultiValueMode sortMode;
         protected final Object missingValue;
         protected final Nested nested;
+        protected boolean enableSkipping;
 
         public XFieldComparatorSource(Object missingValue, MultiValueMode sortMode, Nested nested) {
             this.sortMode = sortMode;
             this.missingValue = missingValue;
             this.nested = nested;
+            this.enableSkipping = true; // true by default
         }
 
         public MultiValueMode sortMode() {
@@ -129,6 +144,10 @@ public Nested nested() {
             return this.nested;
         }
 
+        public void disableSkipping() {
+            this.enableSkipping = false;
+        }
+
         /**
          * Simple wrapper class around a filter that matches parent documents
          * and a filter that matches child documents. For every root document R,
@@ -186,7 +205,7 @@ public final boolean sortMissingLast(Object missingValue) {
         }
 
         /** Return the missing object value according to the reduced type of the comparator. */
-        public final Object missingObject(Object missingValue, boolean reversed) {
+        public Object missingObject(Object missingValue, boolean reversed) {
             if (sortMissingFirst(missingValue) || sortMissingLast(missingValue)) {
                 final boolean min = sortMissingFirst(missingValue) ^ reversed;
                 switch (reducedType()) {
@@ -271,11 +290,21 @@ public abstract BucketedSort newBucketedSort(
         );
     }
 
+    /**
+     * Base builder interface
+     *
+     * @opensearch.internal
+     */
     interface Builder {
 
         IndexFieldData<?> build(IndexFieldDataCache cache, CircuitBreakerService breakerService);
     }
 
+    /**
+     * Base Global field data class
+     *
+     * @opensearch.internal
+     */
     interface Global<FD extends LeafFieldData> extends IndexFieldData<FD> {
 
         IndexFieldData<FD> loadGlobal(DirectoryReader indexReader);
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataCache.java b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataCache.java
index 5d648038112a8..72df2453fc7fd 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataCache.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataCache.java
@@ -35,10 +35,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.util.Accountable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 /**
  * A simple field data cache abstraction on the *index* level.
+ *
+ * @opensearch.internal
  */
 public interface IndexFieldDataCache {
 
@@ -57,6 +59,11 @@ <FD extends LeafFieldData, IFD extends IndexFieldData.Global<FD>> IFD load(Direc
      */
     void clear(String fieldName);
 
+    /**
+     * The listener interface
+     *
+     * @opensearch.internal
+     */
     interface Listener {
 
         /**
@@ -70,6 +77,11 @@ default void onCache(ShardId shardId, String fieldName, Accountable ramUsage) {}
         default void onRemoval(ShardId shardId, String fieldName, boolean wasEvicted, long sizeInBytes) {}
     }
 
+    /**
+     * No index field data cache
+     *
+     * @opensearch.internal
+     */
     class None implements IndexFieldDataCache {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataService.java b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataService.java
index 26fcbb7cc9621..98900482176e5 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataService.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexFieldDataService.java
@@ -36,12 +36,12 @@
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.search.lookup.SearchLookup;
 
@@ -54,6 +54,11 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
+/**
+ * Service for field data (cacheing, etc)
+ *
+ * @opensearch.internal
+ */
 public class IndexFieldDataService extends AbstractIndexComponent implements Closeable {
     public static final String FIELDDATA_CACHE_VALUE_NODE = "node";
     public static final String FIELDDATA_CACHE_KEY = "index.fielddata.cache";
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexGeoPointFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/IndexGeoPointFieldData.java
index 05a704ec2c785..bcee1cd112ab2 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexGeoPointFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexGeoPointFieldData.java
@@ -34,5 +34,7 @@
 
 /**
  * Specialization of {@link IndexFieldData} for geo points.
+ *
+ * @opensearch.internal
  */
 public interface IndexGeoPointFieldData extends IndexFieldData<LeafGeoPointFieldData> {}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexHistogramFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/IndexHistogramFieldData.java
index a2ad4a14408d6..b9d205665d0c7 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexHistogramFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexHistogramFieldData.java
@@ -36,6 +36,8 @@
 
 /**
  * Specialization of {@link IndexFieldData} for histograms.
+ *
+ * @opensearch.internal
  */
 public abstract class IndexHistogramFieldData implements IndexFieldData<LeafHistogramFieldData> {
     protected final String fieldName;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexNumericFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/IndexNumericFieldData.java
index dd987e9f79546..b4e90b8ab570a 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexNumericFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexNumericFieldData.java
@@ -42,7 +42,9 @@
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.fieldcomparator.DoubleValuesComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.FloatValuesComparatorSource;
+import org.opensearch.index.fielddata.fieldcomparator.IntValuesComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.LongValuesComparatorSource;
+import org.opensearch.index.fielddata.fieldcomparator.UnsignedLongValuesComparatorSource;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
@@ -55,22 +57,27 @@
 
 /**
  * Base class for numeric field data.
+ *
+ * @opensearch.internal
  */
 public abstract class IndexNumericFieldData implements IndexFieldData<LeafNumericFieldData> {
     /**
      * The type of number.
+     *
+     * @opensearch.internal
      */
     public enum NumericType {
-        BOOLEAN(false, SortField.Type.LONG, CoreValuesSourceType.BOOLEAN),
-        BYTE(false, SortField.Type.LONG, CoreValuesSourceType.NUMERIC),
-        SHORT(false, SortField.Type.LONG, CoreValuesSourceType.NUMERIC),
-        INT(false, SortField.Type.LONG, CoreValuesSourceType.NUMERIC),
+        BOOLEAN(false, SortField.Type.INT, CoreValuesSourceType.BOOLEAN),
+        BYTE(false, SortField.Type.INT, CoreValuesSourceType.NUMERIC),
+        SHORT(false, SortField.Type.INT, CoreValuesSourceType.NUMERIC),
+        INT(false, SortField.Type.INT, CoreValuesSourceType.NUMERIC),
         LONG(false, SortField.Type.LONG, CoreValuesSourceType.NUMERIC),
         DATE(false, SortField.Type.LONG, CoreValuesSourceType.DATE),
         DATE_NANOSECONDS(false, SortField.Type.LONG, CoreValuesSourceType.DATE),
         HALF_FLOAT(true, SortField.Type.LONG, CoreValuesSourceType.NUMERIC),
         FLOAT(true, SortField.Type.FLOAT, CoreValuesSourceType.NUMERIC),
-        DOUBLE(true, SortField.Type.DOUBLE, CoreValuesSourceType.NUMERIC);
+        DOUBLE(true, SortField.Type.DOUBLE, CoreValuesSourceType.NUMERIC),
+        UNSIGNED_LONG(false, SortField.Type.LONG, CoreValuesSourceType.NUMERIC);
 
         private final boolean floatingPoint;
         private final ValuesSourceType valuesSourceType;
@@ -129,8 +136,6 @@ public final SortField sortField(
             : SortedNumericSelector.Type.MIN;
         SortField sortField = new SortedNumericSortField(getFieldName(), getNumericType().sortFieldType, reverse, selectorType);
         sortField.setMissingValue(source.missingObject(missingValue, reverse));
-        // todo: remove since deprecated
-        sortField.setOptimizeSortWithPoints(false);
         return sortField;
     }
 
@@ -146,6 +151,25 @@ public final SortField sortField(Object missingValue, MultiValueMode sortMode, N
         return sortField(getNumericType(), missingValue, sortMode, nested, reverse);
     }
 
+    @Override
+    public final SortField wideSortField(Object missingValue, MultiValueMode sortMode, Nested nested, boolean reverse) {
+        // This is to support backward compatibility, the minimum number of bytes prior to OpenSearch 2.7 were 16 bytes,
+        // i.e all sort fields were upcasted to Long/Double with 16 bytes.
+        // Now from OpenSearch 2.7, the minimum number of bytes for sort field is 8 bytes, so if it comes as SortField INT,
+        // we need to up cast it to LONG to support backward compatibility info stored in segment info
+        if (getNumericType().sortFieldType == SortField.Type.INT) {
+            XFieldComparatorSource source = comparatorSource(NumericType.LONG, missingValue, sortMode, nested);
+            SortedNumericSelector.Type selectorType = sortMode == MultiValueMode.MAX
+                ? SortedNumericSelector.Type.MAX
+                : SortedNumericSelector.Type.MIN;
+            SortField sortField = new SortedNumericSortField(getFieldName(), SortField.Type.LONG, reverse, selectorType);
+            sortField.setMissingValue(source.missingObject(missingValue, reverse));
+            return sortField;
+        }
+        // If already more than INT, up cast not needed.
+        return sortField(getNumericType(), missingValue, sortMode, nested, reverse);
+    }
+
     /**
      * Builds a {@linkplain BucketedSort} for the {@code targetNumericType},
      * casting the values if their native type doesn't match.
@@ -193,20 +217,35 @@ private XFieldComparatorSource comparatorSource(
         MultiValueMode sortMode,
         Nested nested
     ) {
+        final XFieldComparatorSource source;
         switch (targetNumericType) {
             case HALF_FLOAT:
             case FLOAT:
-                return new FloatValuesComparatorSource(this, missingValue, sortMode, nested);
+                source = new FloatValuesComparatorSource(this, missingValue, sortMode, nested);
+                break;
             case DOUBLE:
-                return new DoubleValuesComparatorSource(this, missingValue, sortMode, nested);
+                source = new DoubleValuesComparatorSource(this, missingValue, sortMode, nested);
+                break;
+            case UNSIGNED_LONG:
+                source = new UnsignedLongValuesComparatorSource(this, missingValue, sortMode, nested);
+                break;
             case DATE:
-                return dateComparatorSource(missingValue, sortMode, nested);
+                source = dateComparatorSource(missingValue, sortMode, nested);
+                break;
             case DATE_NANOSECONDS:
-                return dateNanosComparatorSource(missingValue, sortMode, nested);
+                source = dateNanosComparatorSource(missingValue, sortMode, nested);
+                break;
+            case LONG:
+                source = new LongValuesComparatorSource(this, missingValue, sortMode, nested);
+                break;
             default:
                 assert !targetNumericType.isFloatingPoint();
-                return new LongValuesComparatorSource(this, missingValue, sortMode, nested);
+                source = new IntValuesComparatorSource(this, missingValue, sortMode, nested);
+        }
+        if (targetNumericType != getNumericType()) {
+            source.disableSkipping(); // disable skipping logic for cast of sort field
         }
+        return source;
     }
 
     protected XFieldComparatorSource dateComparatorSource(@Nullable Object missingValue, MultiValueMode sortMode, Nested nested) {
diff --git a/server/src/main/java/org/opensearch/index/fielddata/IndexOrdinalsFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/IndexOrdinalsFieldData.java
index 93f08471bc84a..9831c69744908 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/IndexOrdinalsFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/IndexOrdinalsFieldData.java
@@ -38,6 +38,8 @@
 
 /**
  * Specialization of {@link IndexFieldData} for data that is indexed with ordinals.
+ *
+ * @opensearch.internal
  */
 public interface IndexOrdinalsFieldData extends IndexFieldData.Global<LeafOrdinalsFieldData> {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafFieldData.java
index 52517326e2b6d..2982363937710 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/LeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafFieldData.java
@@ -41,6 +41,8 @@
 
 /**
  * The thread safe {@link org.apache.lucene.index.LeafReader} level cache of the data.
+ *
+ * @opensearch.internal
  */
 public interface LeafFieldData extends Accountable, Releasable {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafGeoPointFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafGeoPointFieldData.java
index 6048e4559b773..bc3a0cfd22516 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/LeafGeoPointFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafGeoPointFieldData.java
@@ -33,6 +33,8 @@
 
 /**
  * {@link LeafFieldData} specialization for geo points.
+ *
+ * @opensearch.internal
  */
 public interface LeafGeoPointFieldData extends LeafFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafGeoShapeFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafGeoShapeFieldData.java
new file mode 100644
index 0000000000000..ab4bc5d411852
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafGeoShapeFieldData.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata;
+
+/**
+ * {@link LeafFieldData} specialization for geo shapes.
+ *
+ * @opensearch.internal
+ */
+public interface LeafGeoShapeFieldData extends LeafFieldData {
+
+    /**
+     * Return the appropriate instance that can be used to read the Geo shape values from lucene.
+     *
+     * @return {@link GeoShapeValue}
+     */
+    GeoShapeValue getGeoShapeValue();
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafHistogramFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafHistogramFieldData.java
index 701ff3e553ac4..e968ecc1e0a38 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/LeafHistogramFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafHistogramFieldData.java
@@ -35,6 +35,8 @@
 
 /**
  * {@link LeafFieldData} specialization for histogram data.
+ *
+ * @opensearch.internal
  */
 public interface LeafHistogramFieldData extends LeafFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafNumericFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafNumericFieldData.java
index 09dd424733ae0..d50da962ecd2a 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/LeafNumericFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafNumericFieldData.java
@@ -36,6 +36,8 @@
 
 /**
  * Specialization of {@link LeafFieldData} for numeric data.
+ *
+ * @opensearch.internal
  */
 public interface LeafNumericFieldData extends LeafFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/LeafOrdinalsFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/LeafOrdinalsFieldData.java
index 09c45885e8ffe..c9b9cbe2796fc 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/LeafOrdinalsFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/LeafOrdinalsFieldData.java
@@ -37,6 +37,8 @@
 /**
  * Specialization of {@link LeafFieldData} for data that is indexed with
  * ordinals.
+ *
+ * @opensearch.internal
  */
 public interface LeafOrdinalsFieldData extends LeafFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/MultiGeoPointValues.java b/server/src/main/java/org/opensearch/index/fielddata/MultiGeoPointValues.java
index e6ac006f2b19f..2df4baeb8631b 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/MultiGeoPointValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/MultiGeoPointValues.java
@@ -49,6 +49,8 @@
  * </pre>
  * The set of values associated with a document might contain duplicates and
  * comes in a non-specified order.
+ *
+ * @opensearch.internal
  */
 public abstract class MultiGeoPointValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/NumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/NumericDoubleValues.java
index ae6fcd514d310..94ea91849ff12 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/NumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/NumericDoubleValues.java
@@ -39,6 +39,8 @@
 
 /**
  * A per-document numeric value.
+ *
+ * @opensearch.internal
  */
 public abstract class NumericDoubleValues extends DoubleValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/RamAccountingTermsEnum.java b/server/src/main/java/org/opensearch/index/fielddata/RamAccountingTermsEnum.java
index 64fee22ac6302..517361e75d3ea 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/RamAccountingTermsEnum.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/RamAccountingTermsEnum.java
@@ -34,7 +34,7 @@
 import org.apache.lucene.index.FilteredTermsEnum;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreaker;
 import org.opensearch.index.fielddata.plain.AbstractIndexOrdinalsFieldData;
 
 import java.io.IOException;
@@ -43,6 +43,8 @@
  * {@link TermsEnum} that takes a CircuitBreaker, increasing the breaker
  * every time {@code .next(...)} is called. Proxies all methods to the original
  * TermsEnum otherwise.
+ *
+ * @opensearch.internal
  */
 public final class RamAccountingTermsEnum extends FilteredTermsEnum {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ScriptDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/ScriptDocValues.java
index 4f0c8d7eb9764..1d1524e223f00 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ScriptDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ScriptDocValues.java
@@ -36,6 +36,7 @@
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.time.DateUtils;
@@ -43,6 +44,7 @@
 import org.opensearch.script.JodaCompatibleZonedDateTime;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.util.AbstractList;
@@ -57,6 +59,8 @@
  * Implementations should not internally re-use objects for the values that they
  * return as a single {@link ScriptDocValues} instance can be reused to return
  * values form multiple documents.
+ *
+ * @opensearch.internal
  */
 public abstract class ScriptDocValues<T> extends AbstractList<T> {
 
@@ -91,6 +95,11 @@ public final void sort(Comparator<? super T> c) {
         throw new UnsupportedOperationException("doc values are unmodifiable");
     }
 
+    /**
+     * Long values for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class Longs extends ScriptDocValues<Long> {
         private final SortedNumericDocValues in;
         private long[] values = new long[0];
@@ -116,7 +125,7 @@ public void setNextDocId(int docId) throws IOException {
         }
 
         /**
-         * Set the {@link #size()} and ensure that the {@link #values} array can
+         * Set the {@link #size()} and ensure that the internal values array can
          * store at least that many entries.
          */
         protected void resize(int newSize) {
@@ -145,6 +154,11 @@ public int size() {
         }
     }
 
+    /**
+     * Date values for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class Dates extends ScriptDocValues<JodaCompatibleZonedDateTime> {
 
         private final SortedNumericDocValues in;
@@ -221,6 +235,11 @@ void refreshArray() throws IOException {
         }
     }
 
+    /**
+     * Double values for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class Doubles extends ScriptDocValues<Double> {
 
         private final SortedNumericDoubleValues in;
@@ -277,6 +296,11 @@ public int size() {
         }
     }
 
+    /**
+     * Geo points for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class GeoPoints extends ScriptDocValues<GeoPoint> {
 
         private final MultiGeoPointValues in;
@@ -397,6 +421,11 @@ public double geohashDistanceWithDefault(String geohash, double defaultValue) {
         }
     }
 
+    /**
+     * Boolean values for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class Booleans extends ScriptDocValues<Boolean> {
 
         private final SortedNumericDocValues in;
@@ -457,6 +486,11 @@ private static boolean[] grow(boolean[] array, int minSize) {
 
     }
 
+    /**
+     * Base class for binary script doc values
+     *
+     * @opensearch.internal
+     */
     abstract static class BinaryScriptDocValues<T> extends ScriptDocValues<T> {
 
         private final SortedBinaryDocValues in;
@@ -483,7 +517,7 @@ public void setNextDocId(int docId) throws IOException {
         }
 
         /**
-         * Set the {@link #size()} and ensure that the {@link #values} array can
+         * Set the {@link #size()} and ensure that the internal values array can
          * store at least that many entries.
          */
         protected void resize(int newSize) {
@@ -503,6 +537,11 @@ public int size() {
         }
     }
 
+    /**
+     * String class for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static class Strings extends BinaryScriptDocValues<String> {
         public Strings(SortedBinaryDocValues in) {
             super(in);
@@ -531,6 +570,11 @@ public final String getValue() {
         }
     }
 
+    /**
+     * BytesRef values for scripted doc values
+     *
+     * @opensearch.internal
+     */
     public static final class BytesRefs extends BinaryScriptDocValues<BytesRef> {
 
         public BytesRefs(SortedBinaryDocValues in) {
@@ -558,4 +602,63 @@ public BytesRef getValue() {
         }
 
     }
+
+    /**
+     * Unsigned long values for scripted doc values (returned as {@link BigInteger})
+     *
+     * @opensearch.internal
+     */
+    public static final class UnsignedLongs extends ScriptDocValues<BigInteger> {
+        private final SortedNumericDocValues in;
+        private BigInteger[] values = new BigInteger[0];
+        private int count;
+
+        /**
+         * Standard constructor.
+         */
+        public UnsignedLongs(SortedNumericDocValues in) {
+            this.in = in;
+        }
+
+        @Override
+        public void setNextDocId(int docId) throws IOException {
+            if (in.advanceExact(docId)) {
+                resize(in.docValueCount());
+                for (int i = 0; i < count; i++) {
+                    values[i] = Numbers.toUnsignedBigInteger(in.nextValue());
+                }
+            } else {
+                resize(0);
+            }
+        }
+
+        /**
+         * Set the {@link #size()} and ensure that the internal values array can
+         * store at least that many entries.
+         */
+        protected void resize(int newSize) {
+            count = newSize;
+            values = ArrayUtil.grow(values, count);
+        }
+
+        public BigInteger getValue() {
+            return get(0);
+        }
+
+        @Override
+        public BigInteger get(int index) {
+            if (count == 0) {
+                throw new IllegalStateException(
+                    "A document doesn't have a value for a field! "
+                        + "Use doc[<field>].size()==0 to check if a document is missing a field!"
+                );
+            }
+            return values[index];
+        }
+
+        @Override
+        public int size() {
+            return count;
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ShardFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/ShardFieldData.java
index 235ec79f18ff2..87da81a0b3443 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ShardFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ShardFieldData.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.index.fielddata;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
 import org.apache.lucene.util.Accountable;
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.index.shard.ShardId;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ConcurrentMap;
 
+/**
+ * On heap field data for shards
+ *
+ * @opensearch.internal
+ */
 public class ShardFieldData implements IndexFieldDataCache.Listener {
 
     private final CounterMetric evictionsMetric = new CounterMetric();
@@ -51,9 +56,9 @@ public class ShardFieldData implements IndexFieldDataCache.Listener {
     private final ConcurrentMap<String, CounterMetric> perFieldTotals = ConcurrentCollections.newConcurrentMap();
 
     public FieldDataStats stats(String... fields) {
-        ObjectLongHashMap<String> fieldTotals = null;
+        Map<String, Long> fieldTotals = null;
         if (CollectionUtils.isEmpty(fields) == false) {
-            fieldTotals = new ObjectLongHashMap<>();
+            fieldTotals = new HashMap<>();
             for (Map.Entry<String, CounterMetric> entry : perFieldTotals.entrySet()) {
                 if (Regex.simpleMatch(fields, entry.getKey())) {
                     fieldTotals.put(entry.getKey(), entry.getValue().count());
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SingletonMultiGeoPointValues.java b/server/src/main/java/org/opensearch/index/fielddata/SingletonMultiGeoPointValues.java
index cd0dd3f69f809..56a3a04eee5be 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SingletonMultiGeoPointValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SingletonMultiGeoPointValues.java
@@ -36,6 +36,11 @@
 
 import java.io.IOException;
 
+/**
+ * Multiple geopoint doc value provider
+ *
+ * @opensearch.internal
+ */
 final class SingletonMultiGeoPointValues extends MultiGeoPointValues {
 
     private final GeoPointValues in;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedBinaryDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedBinaryDocValues.java
index ff4cb72719c61..9496e6ec8a69d 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedBinaryDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedBinaryDocValues.java
@@ -37,6 +37,11 @@
 
 import java.io.IOException;
 
+/**
+ * Provider for sorted binary docvalues
+ *
+ * @opensearch.internal
+ */
 final class SingletonSortedBinaryDocValues extends SortedBinaryDocValues {
 
     private final BinaryDocValues in;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedNumericDoubleValues.java
index 2baac237035b3..4ee494ffb30aa 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedNumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SingletonSortedNumericDoubleValues.java
@@ -39,6 +39,8 @@
  * <p>
  * This can be used if you want to have one multi-valued implementation
  * that works for single or multi-valued types.
+ *
+ * @opensearch.internal
  */
 final class SingletonSortedNumericDoubleValues extends SortedNumericDoubleValues {
     private final NumericDoubleValues in;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsNumericDocValues.java
index 63600f400b844..39aca38c331ea 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsNumericDocValues.java
@@ -41,6 +41,8 @@
  * {@link NumericDocValues} instance that wraps a {@link NumericDoubleValues}
  * and converts the doubles to sortable long bits using
  * {@link NumericUtils#doubleToSortableLong(double)}.
+ *
+ * @opensearch.internal
  */
 final class SortableLongBitsNumericDocValues extends AbstractNumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsSortedNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsSortedNumericDocValues.java
index 702208fd3db58..ef2fcc6e2fa75 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsSortedNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsSortedNumericDocValues.java
@@ -41,6 +41,8 @@
  * {@link SortedNumericDocValues} instance that wraps a {@link SortedNumericDoubleValues}
  * and converts the doubles to sortable long bits using
  * {@link NumericUtils#doubleToSortableLong(double)}.
+ *
+ * @opensearch.internal
  */
 final class SortableLongBitsSortedNumericDocValues extends AbstractSortedNumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToNumericDoubleValues.java
index a585b90e86118..150e114d342de 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToNumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToNumericDoubleValues.java
@@ -41,6 +41,8 @@
  * {@link NumericDoubleValues} instance that wraps a {@link NumericDocValues}
  * and converts the doubles to sortable long bits using
  * {@link NumericUtils#sortableLongToDouble(long)}.
+ *
+ * @opensearch.internal
  */
 final class SortableLongBitsToNumericDoubleValues extends NumericDoubleValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToSortedNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToSortedNumericDoubleValues.java
index 1538fd089ea21..1bae845c9b0d2 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToSortedNumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortableLongBitsToSortedNumericDoubleValues.java
@@ -41,6 +41,8 @@
  * {@link SortedNumericDoubleValues} instance that wraps a {@link SortedNumericDocValues}
  * and converts the doubles to sortable long bits using
  * {@link NumericUtils#sortableLongToDouble(long)}.
+ *
+ * @opensearch.internal
  */
 final class SortableLongBitsToSortedNumericDoubleValues extends SortedNumericDoubleValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortedBinaryDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortedBinaryDocValues.java
index f448c24aa7dc7..bd66d1d94f33c 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortedBinaryDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortedBinaryDocValues.java
@@ -40,6 +40,8 @@
  * A list of per-document binary values, sorted
  * according to {@link BytesRef#compareTo(BytesRef)}.
  * There might be dups however.
+ *
+ * @opensearch.internal
  */
 // TODO: Should it expose a count (current approach) or return null when there are no more values?
 public abstract class SortedBinaryDocValues {
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortedNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortedNumericDoubleValues.java
index 1fe1310e9f693..91d28113ae783 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortedNumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortedNumericDoubleValues.java
@@ -38,6 +38,8 @@
 
 /**
  * Clone of {@link SortedNumericDocValues} for double values.
+ *
+ * @opensearch.internal
  */
 public abstract class SortedNumericDoubleValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortingBinaryDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortingBinaryDocValues.java
index 33efe556acef9..ba415e7bc0276 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortingBinaryDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortingBinaryDocValues.java
@@ -43,6 +43,8 @@
 
 /**
  * Base class for building {@link SortedBinaryDocValues} instances based on unsorted content.
+ *
+ * @opensearch.internal
  */
 public abstract class SortingBinaryDocValues extends SortedBinaryDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDocValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDocValues.java
index 12b6eb4e39340..cdfb1e3252899 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDocValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDocValues.java
@@ -41,6 +41,8 @@
 
 /**
  * Base class for building {@link SortedNumericDocValues} instances based on unsorted content.
+ *
+ * @opensearch.internal
  */
 public abstract class SortingNumericDocValues extends SortedNumericDocValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDoubleValues.java
index 28c72c722dd38..bb125dc600b74 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDoubleValues.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/SortingNumericDoubleValues.java
@@ -38,6 +38,8 @@
 
 /**
  * Base class for building {@link SortedNumericDoubleValues} instances based on unsorted content.
+ *
+ * @opensearch.internal
  */
 public abstract class SortingNumericDoubleValues extends SortedNumericDoubleValues {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToNumericDoubleValues.java
new file mode 100644
index 0000000000000..8d17146760d9e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToNumericDoubleValues.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.index.NumericDocValues;
+import org.opensearch.common.Numbers;
+
+import java.io.IOException;
+
+/**
+ * {@link NumericDoubleValues} instance that wraps a {@link NumericDocValues}
+ * and converts the unsigned long to double using {@link Numbers#unsignedLongToDouble(long)}.
+ *
+ * @opensearch.internal
+ */
+final class UnsignedLongToNumericDoubleValues extends NumericDoubleValues {
+
+    private final NumericDocValues values;
+
+    UnsignedLongToNumericDoubleValues(NumericDocValues values) {
+        this.values = values;
+    }
+
+    @Override
+    public double doubleValue() throws IOException {
+        return Numbers.unsignedLongToDouble(values.longValue());
+    }
+
+    @Override
+    public boolean advanceExact(int doc) throws IOException {
+        return values.advanceExact(doc);
+    }
+
+    /** Return the wrapped values. */
+    public NumericDocValues getLongValues() {
+        return values;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToSortedNumericDoubleValues.java b/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToSortedNumericDoubleValues.java
new file mode 100644
index 0000000000000..90b49e19a8954
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/UnsignedLongToSortedNumericDoubleValues.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.opensearch.common.Numbers;
+
+import java.io.IOException;
+
+/**
+ * {@link SortedNumericDoubleValues} instance that wraps a {@link SortedNumericDocValues}
+ * and converts the unsigned long to double using {@link Numbers#unsignedLongToDouble(long)}.
+ *
+ * @opensearch.internal
+ */
+final class UnsignedLongToSortedNumericDoubleValues extends SortedNumericDoubleValues {
+
+    private final SortedNumericDocValues values;
+
+    UnsignedLongToSortedNumericDoubleValues(SortedNumericDocValues values) {
+        this.values = values;
+    }
+
+    @Override
+    public boolean advanceExact(int target) throws IOException {
+        return values.advanceExact(target);
+    }
+
+    @Override
+    public double nextValue() throws IOException {
+        return Numbers.unsignedLongToDouble(values.nextValue());
+    }
+
+    @Override
+    public int docValueCount() {
+        return values.docValueCount();
+    }
+
+    /** Return the wrapped values. */
+    public SortedNumericDocValues getLongValues() {
+        return values;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/BytesRefFieldComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/BytesRefFieldComparatorSource.java
index d25443914ebaa..ad7bed13b3ccc 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/BytesRefFieldComparatorSource.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/BytesRefFieldComparatorSource.java
@@ -40,6 +40,7 @@
 import org.apache.lucene.search.FieldComparator;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.comparators.TermOrdValComparator;
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.util.BigArrays;
@@ -56,6 +57,8 @@
 
 /**
  * Comparator source for string/binary values.
+ *
+ * @opensearch.internal
  */
 public class BytesRefFieldComparatorSource extends IndexFieldData.XFieldComparatorSource {
 
@@ -88,7 +91,7 @@ protected SortedBinaryDocValues getValues(LeafReaderContext context) throws IOEx
         return indexFieldData.load(context).getBytesValues();
     }
 
-    protected void setScorer(Scorable scorer) {}
+    protected void setScorer(Scorable scorer, LeafReaderContext context) {}
 
     @Override
     public FieldComparator<?> newComparator(String fieldname, int numHits, boolean enableSkipping, boolean reversed) {
@@ -97,8 +100,13 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final boolean sortMissingLast = sortMissingLast(missingValue) ^ reversed;
         final BytesRef missingBytes = (BytesRef) missingObject(missingValue, reversed);
         if (indexFieldData instanceof IndexOrdinalsFieldData) {
-            return new FieldComparator.TermOrdValComparator(numHits, null, sortMissingLast) {
-
+            FieldComparator<?> cmp = new TermOrdValComparator(
+                numHits,
+                indexFieldData.getFieldName(),
+                sortMissingLast,
+                reversed,
+                enableSkipping
+            ) {
                 @Override
                 protected SortedDocValues getSortedDocValues(LeafReaderContext context, String field) throws IOException {
                     final SortedSetDocValues values = ((IndexOrdinalsFieldData) indexFieldData).load(context).getOrdinalsValues();
@@ -119,19 +127,17 @@ protected SortedDocValues getSortedDocValues(LeafReaderContext context, String f
                         return new ReplaceMissing(selectedValues, missingBytes);
                     }
                 }
-
-                @Override
-                public void setScorer(Scorable scorer) {
-                    BytesRefFieldComparatorSource.this.setScorer(scorer);
-                }
-
             };
+            cmp.disableSkipping();
+            return cmp;
         }
 
         return new FieldComparator.TermValComparator(numHits, null, sortMissingLast) {
+            LeafReaderContext leafReaderContext;
 
             @Override
             protected BinaryDocValues getBinaryDocValues(LeafReaderContext context, String field) throws IOException {
+                leafReaderContext = context;
                 final SortedBinaryDocValues values = getValues(context);
                 final BinaryDocValues selectedValues;
                 if (nested == null) {
@@ -147,7 +153,7 @@ protected BinaryDocValues getBinaryDocValues(LeafReaderContext context, String f
 
             @Override
             public void setScorer(Scorable scorer) {
-                BytesRefFieldComparatorSource.this.setScorer(scorer);
+                BytesRefFieldComparatorSource.this.setScorer(scorer, leafReaderContext);
             }
 
         };
@@ -167,6 +173,8 @@ public BucketedSort newBucketedSort(
     /**
      * A view of a SortedDocValues where missing values
      * are replaced with the specified term
+     *
+     * @opensearch.internal
      */
     // TODO: move this out if we need it for other reasons
     static class ReplaceMissing extends AbstractSortedDocValues {
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/DoubleValuesComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/DoubleValuesComparatorSource.java
index 135101eae362d..e70916c33882c 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/DoubleValuesComparatorSource.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/DoubleValuesComparatorSource.java
@@ -57,6 +57,8 @@
 
 /**
  * Comparator source for double values.
+ *
+ * @opensearch.internal
  */
 public class DoubleValuesComparatorSource extends IndexFieldData.XFieldComparatorSource {
 
@@ -93,7 +95,7 @@ private NumericDoubleValues getNumericDocValues(LeafReaderContext context, doubl
         }
     }
 
-    protected void setScorer(Scorable scorer) {}
+    protected void setScorer(Scorable scorer, LeafReaderContext context) {}
 
     @Override
     public FieldComparator<?> newComparator(String fieldname, int numHits, boolean enableSkipping, boolean reversed) {
@@ -102,7 +104,7 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final double dMissingValue = (Double) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new DoubleComparator(numHits, null, null, reversed, false) {
+        return new DoubleComparator(numHits, fieldname, null, reversed, enableSkipping && this.enableSkipping) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new DoubleLeafComparator(context) {
@@ -113,7 +115,7 @@ protected NumericDocValues getNumericDocValues(LeafReaderContext context, String
 
                     @Override
                     public void setScorer(Scorable scorer) {
-                        DoubleValuesComparatorSource.this.setScorer(scorer);
+                        DoubleValuesComparatorSource.this.setScorer(scorer, context);
                     }
                 };
             }
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/FloatValuesComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/FloatValuesComparatorSource.java
index f8371e8235070..04a34cd418520 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/FloatValuesComparatorSource.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/FloatValuesComparatorSource.java
@@ -56,6 +56,8 @@
 
 /**
  * Comparator source for float values.
+ *
+ * @opensearch.internal
  */
 public class FloatValuesComparatorSource extends IndexFieldData.XFieldComparatorSource {
 
@@ -95,7 +97,7 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final float fMissingValue = (Float) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new FloatComparator(numHits, null, null, reversed, false) {
+        return new FloatComparator(numHits, fieldname, null, reversed, enableSkipping && this.enableSkipping) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new FloatLeafComparator(context) {
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/IntValuesComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/IntValuesComparatorSource.java
new file mode 100644
index 0000000000000..d5ea1eaf7263d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/IntValuesComparatorSource.java
@@ -0,0 +1,126 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.index.fielddata.fieldcomparator;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NumericDocValues;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.search.DocIdSetIterator;
+import org.apache.lucene.search.FieldComparator;
+import org.apache.lucene.search.LeafFieldComparator;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.comparators.IntComparator;
+import org.apache.lucene.util.BitSet;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.MultiValueMode;
+import org.opensearch.search.sort.BucketedSort;
+import org.opensearch.search.sort.SortOrder;
+
+import java.io.IOException;
+
+/**
+ * Comparator source for int values.
+ *
+ * @opensearch.internal
+ */
+public class IntValuesComparatorSource extends IndexFieldData.XFieldComparatorSource {
+
+    private final IndexNumericFieldData indexFieldData;
+
+    public IntValuesComparatorSource(
+        IndexNumericFieldData indexFieldData,
+        @Nullable Object missingValue,
+        MultiValueMode sortMode,
+        Nested nested
+    ) {
+        super(missingValue, sortMode, nested);
+        this.indexFieldData = indexFieldData;
+    }
+
+    @Override
+    public SortField.Type reducedType() {
+        return SortField.Type.INT;
+    }
+
+    private NumericDocValues getNumericDocValues(LeafReaderContext context, int missingValue) throws IOException {
+        final SortedNumericDocValues values = indexFieldData.load(context).getLongValues();
+        if (nested == null) {
+            return FieldData.replaceMissing(sortMode.select(values), missingValue);
+        }
+        final BitSet rootDocs = nested.rootDocs(context);
+        final DocIdSetIterator innerDocs = nested.innerDocs(context);
+        final int maxChildren = nested.getNestedSort() != null ? nested.getNestedSort().getMaxChildren() : Integer.MAX_VALUE;
+        return sortMode.select(values, missingValue, rootDocs, innerDocs, context.reader().maxDoc(), maxChildren);
+    }
+
+    @Override
+    public FieldComparator<?> newComparator(String fieldname, int numHits, boolean enableSkipping, boolean reversed) {
+        assert indexFieldData == null || fieldname.equals(indexFieldData.getFieldName());
+
+        final int iMissingValue = (Integer) missingObject(missingValue, reversed);
+        // NOTE: it's important to pass null as a missing value in the constructor so that
+        // the comparator doesn't check docsWithField since we replace missing values in select()
+        return new IntComparator(numHits, fieldname, null, reversed, enableSkipping && this.enableSkipping) {
+            @Override
+            public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
+                return new IntLeafComparator(context) {
+                    @Override
+                    protected NumericDocValues getNumericDocValues(LeafReaderContext context, String field) throws IOException {
+                        return IntValuesComparatorSource.this.getNumericDocValues(context, iMissingValue);
+                    }
+                };
+            }
+        };
+    }
+
+    @Override
+    public BucketedSort newBucketedSort(
+        BigArrays bigArrays,
+        SortOrder sortOrder,
+        DocValueFormat format,
+        int bucketSize,
+        BucketedSort.ExtraData extra
+    ) {
+        return new BucketedSort.ForInts(bigArrays, sortOrder, format, bucketSize, extra) {
+            private final int iMissingValue = (Integer) missingObject(missingValue, sortOrder == SortOrder.DESC);
+
+            @Override
+            public Leaf forLeaf(LeafReaderContext ctx) throws IOException {
+                return new Leaf(ctx) {
+                    private final NumericDocValues docValues = getNumericDocValues(ctx, iMissingValue);
+                    private int docValue;
+
+                    @Override
+                    protected boolean advanceExact(int doc) throws IOException {
+                        if (docValues.advanceExact(doc)) {
+                            docValue = (int) docValues.longValue();
+                            return true;
+                        }
+                        return false;
+                    }
+
+                    @Override
+                    protected int docValue() {
+                        return docValue;
+                    }
+                };
+            }
+        };
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/LongValuesComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/LongValuesComparatorSource.java
index 3871425f1255f..2c67d7ab7e86a 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/LongValuesComparatorSource.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/LongValuesComparatorSource.java
@@ -42,10 +42,10 @@
 import org.apache.lucene.util.BitSet;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.plain.SortedNumericIndexFieldData;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
@@ -57,6 +57,8 @@
 
 /**
  * Comparator source for long values.
+ *
+ * @opensearch.internal
  */
 public class LongValuesComparatorSource extends IndexFieldData.XFieldComparatorSource {
 
@@ -118,7 +120,7 @@ public FieldComparator<?> newComparator(String fieldname, int numHits, boolean e
         final long lMissingValue = (Long) missingObject(missingValue, reversed);
         // NOTE: it's important to pass null as a missing value in the constructor so that
         // the comparator doesn't check docsWithField since we replace missing values in select()
-        return new LongComparator(numHits, null, null, reversed, false) {
+        return new LongComparator(numHits, fieldname, null, reversed, enableSkipping && this.enableSkipping) {
             @Override
             public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
                 return new LongLeafComparator(context) {
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/UnsignedLongValuesComparatorSource.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/UnsignedLongValuesComparatorSource.java
new file mode 100644
index 0000000000000..5416d4fe0fb91
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/UnsignedLongValuesComparatorSource.java
@@ -0,0 +1,143 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata.fieldcomparator;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NumericDocValues;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.search.DocIdSetIterator;
+import org.apache.lucene.search.FieldComparator;
+import org.apache.lucene.search.LeafFieldComparator;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.util.BitSet;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.Numbers;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.index.fielddata.LeafNumericFieldData;
+import org.opensearch.index.search.comparators.UnsignedLongComparator;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.MultiValueMode;
+import org.opensearch.search.sort.BucketedSort;
+import org.opensearch.search.sort.SortOrder;
+
+import java.io.IOException;
+import java.math.BigInteger;
+
+/**
+ * Comparator source for unsigned long values.
+ *
+ * @opensearch.internal
+ */
+public class UnsignedLongValuesComparatorSource extends IndexFieldData.XFieldComparatorSource {
+
+    private final IndexNumericFieldData indexFieldData;
+
+    public UnsignedLongValuesComparatorSource(
+        IndexNumericFieldData indexFieldData,
+        @Nullable Object missingValue,
+        MultiValueMode sortMode,
+        Nested nested
+    ) {
+        super(missingValue, sortMode, nested);
+        this.indexFieldData = indexFieldData;
+    }
+
+    @Override
+    public SortField.Type reducedType() {
+        return SortField.Type.LONG;
+    }
+
+    private SortedNumericDocValues loadDocValues(LeafReaderContext context) {
+        final LeafNumericFieldData data = indexFieldData.load(context);
+        SortedNumericDocValues values = data.getLongValues();
+        return values;
+    }
+
+    private NumericDocValues getNumericDocValues(LeafReaderContext context, BigInteger missingValue) throws IOException {
+        final SortedNumericDocValues values = loadDocValues(context);
+        if (nested == null) {
+            return FieldData.replaceMissing(sortMode.select(values), missingValue);
+        }
+        final BitSet rootDocs = nested.rootDocs(context);
+        final DocIdSetIterator innerDocs = nested.innerDocs(context);
+        final int maxChildren = nested.getNestedSort() != null ? nested.getNestedSort().getMaxChildren() : Integer.MAX_VALUE;
+        return sortMode.select(values, missingValue.longValue(), rootDocs, innerDocs, context.reader().maxDoc(), maxChildren);
+    }
+
+    @Override
+    public Object missingObject(Object missingValue, boolean reversed) {
+        if (sortMissingFirst(missingValue) || sortMissingLast(missingValue)) {
+            final boolean min = sortMissingFirst(missingValue) ^ reversed;
+            return min ? Numbers.MIN_UNSIGNED_LONG_VALUE : Numbers.MAX_UNSIGNED_LONG_VALUE;
+        } else {
+            if (missingValue instanceof Number) {
+                return ((Number) missingValue);
+            } else {
+                return new BigInteger(missingValue.toString());
+            }
+        }
+    }
+
+    @Override
+    public FieldComparator<?> newComparator(String fieldname, int numHits, boolean enableSkipping, boolean reversed) {
+        assert indexFieldData == null || fieldname.equals(indexFieldData.getFieldName());
+
+        final BigInteger ulMissingValue = (BigInteger) missingObject(missingValue, reversed);
+        return new UnsignedLongComparator(numHits, fieldname, null, reversed, enableSkipping && this.enableSkipping) {
+            @Override
+            public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
+                return new UnsignedLongLeafComparator(context) {
+                    @Override
+                    protected NumericDocValues getNumericDocValues(LeafReaderContext context, String field) throws IOException {
+                        return UnsignedLongValuesComparatorSource.this.getNumericDocValues(context, ulMissingValue);
+                    }
+                };
+            }
+        };
+    }
+
+    @Override
+    public BucketedSort newBucketedSort(
+        BigArrays bigArrays,
+        SortOrder sortOrder,
+        DocValueFormat format,
+        int bucketSize,
+        BucketedSort.ExtraData extra
+    ) {
+        return new BucketedSort.ForUnsignedLongs(bigArrays, sortOrder, format, bucketSize, extra) {
+            private final BigInteger ulMissingValue = (BigInteger) missingObject(missingValue, sortOrder == SortOrder.DESC);
+
+            @Override
+            public Leaf forLeaf(LeafReaderContext ctx) throws IOException {
+                return new Leaf(ctx) {
+                    private final NumericDocValues docValues = getNumericDocValues(ctx, ulMissingValue);
+                    private long docValue;
+
+                    @Override
+                    protected boolean advanceExact(int doc) throws IOException {
+                        if (docValues.advanceExact(doc)) {
+                            docValue = docValues.longValue();
+                            return true;
+                        }
+                        return false;
+                    }
+
+                    @Override
+                    protected long docValue() {
+                        return docValue;
+                    }
+                };
+            }
+        };
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/package-info.java b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/package-info.java
new file mode 100644
index 0000000000000..7735d4e8088dd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/fieldcomparator/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing field comparator operations */
+package org.opensearch.index.fielddata.fieldcomparator;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalMapping.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalMapping.java
index be57ac0771ee5..cc5415aacd276 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalMapping.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalMapping.java
@@ -42,6 +42,8 @@
 
 /**
  * A {@link SortedSetDocValues} implementation that returns ordinals that are global.
+ *
+ * @opensearch.internal
  */
 final class GlobalOrdinalMapping extends SortedSetDocValues {
 
@@ -110,4 +112,8 @@ public long cost() {
         return values.cost();
     }
 
+    @Override
+    public int docValueCount() {
+        return values.docValueCount();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
index 0ed496b5a459f..06219b69266b5 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsBuilder.java
@@ -39,13 +39,13 @@
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.packed.PackedInts;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
 import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.plain.AbstractLeafOrdinalsFieldData;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -55,6 +55,8 @@
 
 /**
  * Utility class to build global ordinals.
+ *
+ * @opensearch.internal
  */
 public enum GlobalOrdinalsBuilder {
     ;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
index ec554ae78996d..90541b3a9f1c0 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/GlobalOrdinalsIndexFieldData.java
@@ -65,6 +65,8 @@
  * Each instance of {@link Consumer} uses a new set of {@link TermsEnum} that can be reused during the collection,
  * this is done to avoid creating all segment's {@link TermsEnum} each time we want to access the values of a single
  * segment.
+ *
+ * @opensearch.internal
  */
 public final class GlobalOrdinalsIndexFieldData implements IndexOrdinalsFieldData, Accountable {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/MultiOrdinals.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/MultiOrdinals.java
index 2af4cab7cbdee..daccb5dfe9fca 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/MultiOrdinals.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/MultiOrdinals.java
@@ -51,6 +51,8 @@
 
 /**
  * {@link Ordinals} implementation which is efficient at storing field data ordinals for multi-valued or sparse fields.
+ *
+ * @opensearch.internal
  */
 public class MultiOrdinals extends Ordinals {
 
@@ -127,6 +129,11 @@ public SortedSetDocValues ordinals(ValuesHolder values) {
         }
     }
 
+    /**
+     * Single doc type
+     *
+     * @opensearch.internal
+     */
     private static class SingleDocs extends AbstractSortedDocValues {
 
         private final int valueCount;
@@ -175,6 +182,11 @@ public int getValueCount() {
 
     }
 
+    /**
+     * Multiple docs
+     *
+     * @opensearch.internal
+     */
     private static class MultiDocs extends AbstractSortedSetDocValues {
 
         private final long valueCount;
@@ -217,5 +229,10 @@ public long nextOrd() throws IOException {
         public BytesRef lookupOrd(long ord) {
             return values.lookupOrd(ord);
         }
+
+        @Override
+        public int docValueCount() {
+            return Math.toIntExact(currentEndOffset - currentOffset);
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/Ordinals.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/Ordinals.java
index 52752a828df86..85ac535319e55 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/Ordinals.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/Ordinals.java
@@ -38,6 +38,8 @@
 
 /**
  * A thread safe ordinals abstraction. Ordinals can only be positive integers.
+ *
+ * @opensearch.internal
  */
 public abstract class Ordinals implements Accountable {
 
@@ -60,6 +62,11 @@ public final SortedSetDocValues ordinals() {
         return ordinals(NO_VALUES);
     }
 
+    /**
+     * Holder of values
+     *
+     * @opensearch.internal
+     */
     public interface ValuesHolder {
 
         BytesRef lookupOrd(long ord);
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/OrdinalsBuilder.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/OrdinalsBuilder.java
index 5439c884b322f..ea6baa1f2c684 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/OrdinalsBuilder.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/OrdinalsBuilder.java
@@ -46,6 +46,8 @@
  * Simple class to build document ID &lt;-&gt; ordinal mapping. Note: Ordinals are
  * {@code 1} based monotonically increasing positive integers. {@code 0}
  * donates the missing value in this context.
+ *
+ * @opensearch.internal
  */
 public final class OrdinalsBuilder implements Closeable {
 
@@ -82,6 +84,8 @@ public final class OrdinalsBuilder implements Closeable {
      * <p>
      * In addition to these structures, there is another array which stores the current position (level + slice + offset in the slice)
      * in order to be able to append data in constant time.
+     *
+     * @opensearch.internal
      */
     private static class OrdinalsStore {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/SinglePackedOrdinals.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/SinglePackedOrdinals.java
index a93da9495fbfb..a3007cded317e 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/ordinals/SinglePackedOrdinals.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/SinglePackedOrdinals.java
@@ -45,7 +45,12 @@
 import java.util.Collection;
 import java.util.Collections;
 
-public class SinglePackedOrdinals extends Ordinals {
+/**
+ * Packed ordinals for a single field
+ *
+ * @opensearch.internal
+ */
+class SinglePackedOrdinals extends Ordinals {
 
     // ordinals with value 0 indicates no value
     private final PackedInts.Reader reader;
@@ -79,6 +84,11 @@ public SortedSetDocValues ordinals(ValuesHolder values) {
         return (SortedSetDocValues) DocValues.singleton(new Docs(this, values));
     }
 
+    /**
+     * Doc class
+     *
+     * @opensearch.internal
+     */
     private static class Docs extends AbstractSortedDocValues {
 
         private final int maxOrd;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/ordinals/package-info.java b/server/src/main/java/org/opensearch/index/fielddata/ordinals/package-info.java
new file mode 100644
index 0000000000000..275bd283cf90f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/ordinals/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all field ordinals operations */
+package org.opensearch.index.fielddata.ordinals;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/package-info.java b/server/src/main/java/org/opensearch/index/fielddata/package-info.java
new file mode 100644
index 0000000000000..6892a82fdbfaa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all field data logic */
+package org.opensearch.index.fielddata;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractBinaryDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractBinaryDVLeafFieldData.java
index 787401386c120..b0cb473f6f08d 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractBinaryDVLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractBinaryDVLeafFieldData.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.index.BinaryDocValues;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
 import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
 
@@ -43,6 +43,11 @@
 import java.util.Collection;
 import java.util.Collections;
 
+/**
+ * Base class for binary docvalue "field data"
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractBinaryDVLeafFieldData implements LeafFieldData {
     private final BinaryDocValues values;
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractGeoShapeIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractGeoShapeIndexFieldData.java
new file mode 100644
index 0000000000000..53d60d56bcd07
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractGeoShapeIndexFieldData.java
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata.plain;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.SortField;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.IndexFieldDataCache;
+import org.opensearch.index.fielddata.LeafGeoShapeFieldData;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.MultiValueMode;
+import org.opensearch.search.aggregations.support.ValuesSourceType;
+import org.opensearch.search.sort.BucketedSort;
+import org.opensearch.search.sort.SortOrder;
+
+/**
+ * Base class for retrieving Geometry docvalues
+ *
+ * @opensearch.internal
+ */
+public abstract class AbstractGeoShapeIndexFieldData implements IndexFieldData<LeafGeoShapeFieldData> {
+    protected final String fieldName;
+    protected final ValuesSourceType valuesSourceType;
+
+    AbstractGeoShapeIndexFieldData(String fieldName, ValuesSourceType valuesSourceType) {
+        this.fieldName = fieldName;
+        this.valuesSourceType = valuesSourceType;
+    }
+
+    @Override
+    public final String getFieldName() {
+        return fieldName;
+    }
+
+    @Override
+    public ValuesSourceType getValuesSourceType() {
+        return valuesSourceType;
+    }
+
+    /**
+     * Returns the {@link SortField} to use for sorting.
+     */
+    @Override
+    public SortField sortField(
+        @Nullable Object missingValue,
+        MultiValueMode sortMode,
+        XFieldComparatorSource.Nested nested,
+        boolean reverse
+    ) {
+        throw new IllegalArgumentException("can't sort on geo_shape field without using specific sorting feature, like geo_distance");
+    }
+
+    /**
+     * Build a sort implementation specialized for aggregations.
+     */
+    @Override
+    public BucketedSort newBucketedSort(
+        BigArrays bigArrays,
+        Object missingValue,
+        MultiValueMode sortMode,
+        XFieldComparatorSource.Nested nested,
+        SortOrder sortOrder,
+        DocValueFormat format,
+        int bucketSize,
+        BucketedSort.ExtraData extra
+    ) {
+        throw new IllegalArgumentException("can't sort on geo_shape field without using specific sorting feature, like geo_distance");
+    }
+
+    /**
+     * A concrete implementation of {@link AbstractGeoShapeIndexFieldData} which provides how to load the field data
+     * aka Doc Values from Lucene.
+     */
+    public static class GeoShapeIndexFieldData extends AbstractGeoShapeIndexFieldData {
+
+        public GeoShapeIndexFieldData(String fieldName, ValuesSourceType valuesSourceType) {
+            super(fieldName, valuesSourceType);
+        }
+
+        /**
+         * Loads the atomic field data for the reader, possibly cached.
+         *
+         * @param context {@link LeafReaderContext}
+         */
+        @Override
+        public LeafGeoShapeFieldData load(LeafReaderContext context) {
+            // do a compatibility check for the fieldName by getting the
+            // filed info from the context.
+            return new GeoShapeDVLeafFieldData(context.reader(), fieldName);
+        }
+
+        /**
+         * Loads directly the atomic field data for the reader, ignoring any caching involved.
+         *
+         * @param context {@link LeafReaderContext}
+         */
+        @Override
+        public LeafGeoShapeFieldData loadDirect(LeafReaderContext context) throws Exception {
+            return load(context);
+        }
+    }
+
+    /**
+     * Builder class for creating the GeoShapeIndexFieldData.
+     * This is required the way the indexfieldData is created via the builder class only.
+     * @opensearch.internal
+     */
+    public static class Builder implements IndexFieldData.Builder {
+        private final String name;
+        private final ValuesSourceType valuesSourceType;
+
+        public Builder(String name, ValuesSourceType valuesSourceType) {
+            this.name = name;
+            this.valuesSourceType = valuesSourceType;
+        }
+
+        @Override
+        public IndexFieldData<?> build(IndexFieldDataCache cache, CircuitBreakerService breakerService) {
+            // ignore breaker
+            return new AbstractGeoShapeIndexFieldData.GeoShapeIndexFieldData(name, valuesSourceType);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
index 2102234fdbcc5..b9f7f3824feb4 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractIndexOrdinalsFieldData.java
@@ -41,6 +41,7 @@
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
 import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
@@ -48,12 +49,16 @@
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.ordinals.GlobalOrdinalsBuilder;
 import org.opensearch.index.fielddata.ordinals.GlobalOrdinalsIndexFieldData;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
 
 import java.io.IOException;
 import java.util.function.Function;
 
+/**
+ * Base class for sorting ordinals field data
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractIndexOrdinalsFieldData implements IndexOrdinalsFieldData {
     private static final Logger logger = LogManager.getLogger(AbstractBinaryDVLeafFieldData.class);
 
@@ -177,6 +182,8 @@ public boolean supportsGlobalOrdinalsMapping() {
      * <p>
      * Note that the .beforeLoad(...) and .afterLoad(...) methods must be
      * manually called.
+     *
+     * @opensearch.internal
      */
     public interface PerValueEstimator {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLatLonPointIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLatLonPointIndexFieldData.java
index 5fefc2fdcef3f..be6d4d2aae3a1 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLatLonPointIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLatLonPointIndexFieldData.java
@@ -39,18 +39,23 @@
 import org.apache.lucene.search.SortField;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.fielddata.IndexGeoPointFieldData;
 import org.opensearch.index.fielddata.LeafGeoPointFieldData;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
 import org.opensearch.search.sort.BucketedSort;
 import org.opensearch.search.sort.SortOrder;
 
+/**
+ * Base class for sorting LatLonPoint docvalues
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractLatLonPointIndexFieldData implements IndexGeoPointFieldData {
 
     protected final String fieldName;
@@ -95,6 +100,11 @@ public BucketedSort newBucketedSort(
         throw new IllegalArgumentException("can't sort on geo_point field without using specific sorting feature, like geo_distance");
     }
 
+    /**
+     * Lucene LatLonPoint as indexed field data type
+     *
+     * @opensearch.internal
+     */
     public static class LatLonPointIndexFieldData extends AbstractLatLonPointIndexFieldData {
         public LatLonPointIndexFieldData(String fieldName, ValuesSourceType valuesSourceType) {
             super(fieldName, valuesSourceType);
@@ -133,6 +143,11 @@ static void checkCompatible(FieldInfo fieldInfo) {
         }
     }
 
+    /**
+     * Builder for LatLonPoint based field data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final ValuesSourceType valuesSourceType;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoPointFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoPointFieldData.java
index f614d8aaef51a..7b5c70e0ac756 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoPointFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoPointFieldData.java
@@ -32,8 +32,8 @@
 package org.opensearch.index.fielddata.plain;
 
 import org.apache.lucene.util.Accountable;
-import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.LeafGeoPointFieldData;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
@@ -41,6 +41,11 @@
 import java.util.Collection;
 import java.util.Collections;
 
+/**
+ * Base class for retrieving LatLonPoint docvalues
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractLeafGeoPointFieldData implements LeafGeoPointFieldData {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoShapeFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoShapeFieldData.java
new file mode 100644
index 0000000000000..1c190b4282d67
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafGeoShapeFieldData.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata.plain;
+
+import org.apache.lucene.document.LatLonShapeDocValuesField;
+import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.LeafGeoShapeFieldData;
+import org.opensearch.index.fielddata.ScriptDocValues;
+import org.opensearch.index.fielddata.SortedBinaryDocValues;
+import org.opensearch.search.aggregations.AggregationExecutionException;
+
+/**
+ * Base class for retrieving GeoShape doc values which are added as {@link LatLonShapeDocValuesField} in Lucene
+ */
+public abstract class AbstractLeafGeoShapeFieldData implements LeafGeoShapeFieldData {
+
+    /**
+     * Return a String representation of the values.
+     */
+    @Override
+    public final SortedBinaryDocValues getBytesValues() {
+        return FieldData.toString(getGeoShapeValue());
+    }
+
+    /**
+     * Returns field values for use in scripting. We don't support Script values in the GeoShape for now.
+     * Code should not come to this place, as we have added not to support this at:
+     * CoreValuesSourceTypeGEO_SHAPE
+     */
+    @Override
+    public final ScriptDocValues<?> getScriptValues() {
+        // TODO: https://github.com/opensearch-project/geospatial/issues/128
+        throw new AggregationExecutionException("Script doc value for the GeoShape field is not supported");
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafOrdinalsFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafOrdinalsFieldData.java
index 736b1f5e61ce7..8c319669f53ba 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafOrdinalsFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/AbstractLeafOrdinalsFieldData.java
@@ -35,8 +35,8 @@
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.util.Accountable;
-import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
 
@@ -44,6 +44,11 @@
 import java.util.Collections;
 import java.util.function.Function;
 
+/**
+ * Baseclass for ordinals docvalues
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractLeafOrdinalsFieldData implements LeafOrdinalsFieldData {
 
     public static final Function<SortedSetDocValues, ScriptDocValues<?>> DEFAULT_SCRIPT_FUNCTION = ((Function<
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryDVLeafFieldData.java
index 24936c8f3d665..ec71f1d5dd9dc 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryDVLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryDVLeafFieldData.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.util.Accountable;
-import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.FieldData;
+import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.ScriptDocValues.Strings;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
@@ -46,7 +46,11 @@
 import java.util.Collection;
 import java.util.Collections;
 
-/** {@link LeafFieldData} impl on top of Lucene's binary doc values. */
+/**
+ * {@link LeafFieldData} impl on top of Lucene's binary doc values.
+ *
+ * @opensearch.internal
+ */
 public class BinaryDVLeafFieldData implements LeafFieldData {
 
     private final LeafReader reader;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryIndexFieldData.java
index 3038b9b10ef83..cfa73be8a3670 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/BinaryIndexFieldData.java
@@ -36,19 +36,29 @@
 import org.apache.lucene.search.SortField;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
 import org.opensearch.search.sort.BucketedSort;
 import org.opensearch.search.sort.SortOrder;
 
+/**
+ * Binary doc values ValuesSource
+ *
+ * @opensearch.internal
+ */
 public class BinaryIndexFieldData implements IndexFieldData<BinaryDVLeafFieldData> {
 
+    /**
+     * Builder for binary index field data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final ValuesSourceType valuesSourceType;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryDVLeafFieldData.java
index 7df4a415917e2..247658cabb8da 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryDVLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryDVLeafFieldData.java
@@ -36,6 +36,11 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.fielddata.ScriptDocValues;
 
+/**
+ * Binary valuessource for scripting
+ *
+ * @opensearch.internal
+ */
 final class BytesBinaryDVLeafFieldData extends AbstractBinaryDVLeafFieldData {
     BytesBinaryDVLeafFieldData(BinaryDocValues values) {
         super(values);
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryIndexFieldData.java
index 029beaf587a27..86f5f2d04e14c 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/BytesBinaryIndexFieldData.java
@@ -37,10 +37,10 @@
 import org.apache.lucene.search.SortField;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
@@ -49,6 +49,11 @@
 
 import java.io.IOException;
 
+/**
+ * Binary docvalue values source
+ *
+ * @opensearch.internal
+ */
 public class BytesBinaryIndexFieldData implements IndexFieldData<BytesBinaryDVLeafFieldData> {
 
     protected final String fieldName;
@@ -102,6 +107,11 @@ public BytesBinaryDVLeafFieldData loadDirect(LeafReaderContext context) throws E
         return load(context);
     }
 
+    /**
+     * Builder for bytes binary index field data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final ValuesSourceType valuesSourceType;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/ConstantIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/ConstantIndexFieldData.java
index 763d6b27f74ee..a9eea30dceca5 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/ConstantIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/ConstantIndexFieldData.java
@@ -42,6 +42,7 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.AbstractSortedDocValues;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
@@ -49,7 +50,6 @@
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
 import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
@@ -59,8 +59,18 @@
 import java.util.Collection;
 import java.util.Collections;
 
+/**
+ * Constant value field data
+ *
+ * @opensearch.internal
+ */
 public class ConstantIndexFieldData extends AbstractIndexOrdinalsFieldData {
 
+    /**
+     * Builder for Constant Index Field Data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
 
         private final String constantValue;
@@ -79,6 +89,11 @@ public IndexFieldData<?> build(IndexFieldDataCache cache, CircuitBreakerService
         }
     }
 
+    /**
+     * Field data for constant values
+     *
+     * @opensearch.internal
+     */
     private static class ConstantLeafFieldData extends AbstractLeafOrdinalsFieldData {
 
         private final String value;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/GeoShapeDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/GeoShapeDVLeafFieldData.java
new file mode 100644
index 0000000000000..8089abfdd7c00
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/GeoShapeDVLeafFieldData.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata.plain;
+
+import org.apache.lucene.document.LatLonShapeDocValuesField;
+import org.apache.lucene.index.DocValues;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.util.Accountable;
+import org.apache.lucene.util.Accountables;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.index.fielddata.GeoShapeValue;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * This is the class that converts the DocValue of GeoShape field which is stored in Binary form using
+ * {@link LatLonShapeDocValuesField} to {@link GeoShapeDocValue}.
+ *
+ * @opensearch.internal
+ */
+public class GeoShapeDVLeafFieldData extends AbstractLeafGeoShapeFieldData {
+
+    private final LeafReader reader;
+    private final String fieldName;
+
+    GeoShapeDVLeafFieldData(final LeafReader reader, String fieldName) {
+        super();
+        this.reader = reader;
+        this.fieldName = fieldName;
+    }
+
+    /**
+     * Return the memory usage of this object in bytes. Negative values are illegal.
+     */
+    @Override
+    public long ramBytesUsed() {
+        return 0; // not exposed by lucene
+    }
+
+    @Override
+    public void close() {
+        // noop
+    }
+
+    /**
+     * Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid
+     * race conditions).
+     *
+     * @see Accountables
+     */
+    @Override
+    public Collection<Accountable> getChildResources() {
+        return Collections.emptyList();
+    }
+
+    /**
+     * Reads the binary data from the {@link LeafReader} for a geo shape field and returns
+     * {@link GeoShapeValue.StandardGeoShapeValue} instance which can be used to get the doc values from Lucene.
+     *
+     * @return {@link GeoShapeValue.StandardGeoShapeValue}
+     */
+    @Override
+    public GeoShapeValue getGeoShapeValue() {
+        try {
+            // Using BinaryDocValues as LatLonShapeDocValuesField stores data in binary form.
+            return new GeoShapeValue.StandardGeoShapeValue(DocValues.getBinary(reader, fieldName), fieldName);
+        } catch (IOException e) {
+            throw new IllegalStateException("Cannot load GeoShapeDocValues from lucene", e);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/LatLonPointDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/LatLonPointDVLeafFieldData.java
index 6b7e182a98af9..814dc1cdd237b 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/LatLonPointDVLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/LatLonPointDVLeafFieldData.java
@@ -43,6 +43,11 @@
 import java.util.Collection;
 import java.util.Collections;
 
+/**
+ * LatLonPoint field data
+ *
+ * @opensearch.internal
+ */
 final class LatLonPointDVLeafFieldData extends AbstractLeafGeoPointFieldData {
     private final LeafReader reader;
     private final String fieldName;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/LeafDoubleFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/LeafDoubleFieldData.java
index e74f6f44752a5..47dc02ef093de 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/LeafDoubleFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/LeafDoubleFieldData.java
@@ -48,6 +48,8 @@
 
 /**
  * Specialization of {@link LeafNumericFieldData} for floating-point numerics.
+ *
+ * @opensearch.internal
  */
 public abstract class LeafDoubleFieldData implements LeafNumericFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/LeafLongFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/LeafLongFieldData.java
index 94e44853f74ae..408021dd5f096 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/LeafLongFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/LeafLongFieldData.java
@@ -46,6 +46,8 @@
 
 /**
  * Specialization of {@link LeafNumericFieldData} for integers.
+ *
+ * @opensearch.internal
  */
 public abstract class LeafLongFieldData implements LeafNumericFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesIndexFieldData.java
index e661b61548cd0..bae7130dca4b3 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesIndexFieldData.java
@@ -44,8 +44,9 @@
 import org.apache.lucene.util.packed.PackedInts;
 import org.apache.lucene.util.packed.PackedLongValues;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
@@ -55,7 +56,6 @@
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
 import org.opensearch.index.fielddata.ordinals.Ordinals;
 import org.opensearch.index.fielddata.ordinals.OrdinalsBuilder;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
@@ -64,11 +64,21 @@
 
 import java.io.IOException;
 
+/**
+ * Doc Values for paged bytes
+ *
+ * @opensearch.internal
+ */
 public class PagedBytesIndexFieldData extends AbstractIndexOrdinalsFieldData {
 
     private final double minFrequency, maxFrequency;
     private final int minSegmentSize;
 
+    /**
+     * Builder for paged bytes index field data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final double minFrequency, maxFrequency;
@@ -275,6 +285,11 @@ public void afterLoad(TermsEnum termsEnum, long actualUsed) {
         }
     }
 
+    /**
+     * A frequency filter
+     *
+     * @opensearch.internal
+     */
     private static final class FrequencyFilter extends FilteredTermsEnum {
         private final int minFreq;
         private final int maxFreq;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesLeafFieldData.java
index bbd8ef4645718..0dcdef19b1357 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/PagedBytesLeafFieldData.java
@@ -44,6 +44,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Field Data for Paged Bytes
+ *
+ * @opensearch.internal
+ */
 public class PagedBytesLeafFieldData extends AbstractLeafOrdinalsFieldData {
 
     private final PagedBytes.Reader bytes;
@@ -84,6 +89,11 @@ public SortedSetDocValues getOrdinalsValues() {
         return ordinals.ordinals(new ValuesHolder(bytes, termOrdToBytesOffset));
     }
 
+    /**
+     * Value holder for paged bytes leaf field data
+     *
+     * @opensearch.internal
+     */
     private static class ValuesHolder implements Ordinals.ValuesHolder {
 
         private final BytesRef scratch = new BytesRef();
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedNumericIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedNumericIndexFieldData.java
index 714b762f81fb7..b70752df9e826 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedNumericIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedNumericIndexFieldData.java
@@ -38,9 +38,11 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.NumericDocValues;
 import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.sandbox.document.HalfFloatPoint;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.time.DateUtils;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
@@ -48,16 +50,17 @@
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.fielddata.LeafNumericFieldData;
 import org.opensearch.index.fielddata.NumericDoubleValues;
+import org.opensearch.index.fielddata.ScriptDocValues;
+import org.opensearch.index.fielddata.SortedBinaryDocValues;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.fielddata.fieldcomparator.LongValuesComparatorSource;
 import org.opensearch.index.mapper.DocValueFetcher;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.apache.lucene.sandbox.document.HalfFloatPoint;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Objects;
@@ -65,8 +68,16 @@
 /**
  * FieldData backed by {@link LeafReader#getSortedNumericDocValues(String)}
  * @see DocValuesType#SORTED_NUMERIC
+ *
+ * @opensearch.internal
  */
 public class SortedNumericIndexFieldData extends IndexNumericFieldData {
+
+    /**
+     * Builder for sorted numeric index field data
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final NumericType numericType;
@@ -104,7 +115,7 @@ public ValuesSourceType getValuesSourceType() {
 
     @Override
     protected boolean sortRequiresCustomComparator() {
-        return numericType == NumericType.HALF_FLOAT;
+        return numericType == NumericType.HALF_FLOAT || numericType == NumericType.UNSIGNED_LONG;
     }
 
     @Override
@@ -161,6 +172,8 @@ public LeafNumericFieldData load(LeafReaderContext context) {
                 return new SortedNumericDoubleFieldData(reader, field);
             case DATE_NANOSECONDS:
                 return new NanoSecondFieldData(reader, field, numericType);
+            case UNSIGNED_LONG:
+                return new SortedNumericUnsignedLongFieldData(reader, field);
             default:
                 return new SortedNumericLongFieldData(reader, field, numericType);
         }
@@ -227,6 +240,8 @@ public Object nextValue() throws IOException {
      * for the case where documents have at most one value. In this case
      * {@link DocValues#unwrapSingleton(SortedNumericDocValues)} will return
      * the underlying single-valued NumericDocValues representation.
+     *
+     * @opensearch.internal
      */
     static final class SortedNumericLongFieldData extends LeafLongFieldData {
         final LeafReader reader;
@@ -265,6 +280,8 @@ public Collection<Accountable> getChildResources() {
      * for the case where documents have at most one value. In this case
      * {@link FieldData#unwrapSingleton(SortedNumericDoubleValues)} will return
      * the underlying single-valued NumericDoubleValues representation.
+     *
+     * @opensearch.internal
      */
     static final class SortedNumericHalfFloatFieldData extends LeafDoubleFieldData {
         final LeafReader reader;
@@ -300,6 +317,8 @@ public Collection<Accountable> getChildResources() {
 
     /**
      * Wraps a NumericDocValues and exposes a single 16-bit float per document.
+     *
+     * @opensearch.internal
      */
     static final class SingleHalfFloatValues extends NumericDoubleValues {
         final NumericDocValues in;
@@ -321,6 +340,8 @@ public boolean advanceExact(int doc) throws IOException {
 
     /**
      * Wraps a SortedNumericDocValues and exposes multiple 16-bit floats per document.
+     *
+     * @opensearch.internal
      */
     static final class MultiHalfFloatValues extends SortedNumericDoubleValues {
         final SortedNumericDocValues in;
@@ -357,6 +378,8 @@ public int docValueCount() {
      * for the case where documents have at most one value. In this case
      * {@link FieldData#unwrapSingleton(SortedNumericDoubleValues)} will return
      * the underlying single-valued NumericDoubleValues representation.
+     *
+     * @opensearch.internal
      */
     static final class SortedNumericFloatFieldData extends LeafDoubleFieldData {
         final LeafReader reader;
@@ -392,6 +415,8 @@ public Collection<Accountable> getChildResources() {
 
     /**
      * Wraps a NumericDocValues and exposes a single 32-bit float per document.
+     *
+     * @opensearch.internal
      */
     static final class SingleFloatValues extends NumericDoubleValues {
         final NumericDocValues in;
@@ -413,6 +438,8 @@ public boolean advanceExact(int doc) throws IOException {
 
     /**
      * Wraps a SortedNumericDocValues and exposes multiple 32-bit floats per document.
+     *
+     * @opensearch.internal
      */
     static final class MultiFloatValues extends SortedNumericDoubleValues {
         final SortedNumericDocValues in;
@@ -449,6 +476,8 @@ public int docValueCount() {
      * for the case where documents have at most one value. In this case
      * {@link FieldData#unwrapSingleton(SortedNumericDoubleValues)} will return
      * the underlying single-valued NumericDoubleValues representation.
+     *
+     * @opensearch.internal
      */
     static final class SortedNumericDoubleFieldData extends LeafDoubleFieldData {
         final LeafReader reader;
@@ -475,4 +504,61 @@ public Collection<Accountable> getChildResources() {
             return Collections.emptyList();
         }
     }
+
+    /**
+     * Wraps a NumericDocValues and exposes a single 64-bit double per document.
+     *
+     * @opensearch.internal
+     */
+    static final class SortedNumericUnsignedLongFieldData implements LeafNumericFieldData {
+        final LeafReader reader;
+        final String field;
+
+        SortedNumericUnsignedLongFieldData(LeafReader reader, String field) {
+            this.reader = reader;
+            this.field = field;
+        }
+
+        @Override
+        public SortedNumericDocValues getLongValues() {
+            try {
+                return DocValues.getSortedNumeric(reader, field);
+            } catch (IOException e) {
+                throw new IllegalStateException("Cannot load doc values", e);
+            }
+        }
+
+        @Override
+        public SortedNumericDoubleValues getDoubleValues() {
+            try {
+                SortedNumericDocValues raw = DocValues.getSortedNumeric(reader, field);
+                return FieldData.unsignedLongToDoubles(raw);
+            } catch (IOException e) {
+                throw new IllegalStateException("Cannot load doc values", e);
+            }
+        }
+
+        @Override
+        public Collection<Accountable> getChildResources() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public final ScriptDocValues<BigInteger> getScriptValues() {
+            return new ScriptDocValues.UnsignedLongs(getLongValues());
+        }
+
+        @Override
+        public final SortedBinaryDocValues getBytesValues() {
+            return FieldData.toUnsignedString(getLongValues());
+        }
+
+        @Override
+        public long ramBytesUsed() {
+            return 0L;
+        }
+
+        @Override
+        public void close() {}
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetBytesLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetBytesLeafFieldData.java
index bb7d44938c03d..89502a6358881 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetBytesLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetBytesLeafFieldData.java
@@ -46,6 +46,8 @@
 
 /**
  * An {@link LeafFieldData} implementation that uses Lucene {@link SortedSetDocValues}.
+ *
+ * @opensearch.internal
  */
 public final class SortedSetBytesLeafFieldData extends AbstractLeafOrdinalsFieldData {
 
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetOrdinalsIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetOrdinalsIndexFieldData.java
index ef69cb69e84c9..4f27c9b10f0ee 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetOrdinalsIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/SortedSetOrdinalsIndexFieldData.java
@@ -40,13 +40,13 @@
 import org.apache.lucene.search.SortedSetSortField;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.ValuesSourceType;
@@ -55,8 +55,18 @@
 
 import java.util.function.Function;
 
+/**
+ * Sorted Set Ordinals doc values
+ *
+ * @opensearch.internal
+ */
 public class SortedSetOrdinalsIndexFieldData extends AbstractIndexOrdinalsFieldData {
 
+    /**
+     * Builder for sorted set ordinals
+     *
+     * @opensearch.internal
+     */
     public static class Builder implements IndexFieldData.Builder {
         private final String name;
         private final Function<SortedSetDocValues, ScriptDocValues<?>> scriptFunction;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryDVLeafFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryDVLeafFieldData.java
index 137f1ad22ea9f..1c0f13ff13f23 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryDVLeafFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryDVLeafFieldData.java
@@ -35,6 +35,11 @@
 import org.apache.lucene.index.BinaryDocValues;
 import org.opensearch.index.fielddata.ScriptDocValues;
 
+/**
+ * Field data for binary strings
+ *
+ * @opensearch.internal
+ */
 final class StringBinaryDVLeafFieldData extends AbstractBinaryDVLeafFieldData {
     StringBinaryDVLeafFieldData(BinaryDocValues values) {
         super(values);
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryIndexFieldData.java b/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryIndexFieldData.java
index 72c39acec4e90..9e0c494d9432d 100644
--- a/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryIndexFieldData.java
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/StringBinaryIndexFieldData.java
@@ -47,6 +47,11 @@
 
 import java.io.IOException;
 
+/**
+ * Field Data for binary strings
+ *
+ * @opensearch.internal
+ */
 public class StringBinaryIndexFieldData implements IndexFieldData<StringBinaryDVLeafFieldData> {
 
     protected final String fieldName;
diff --git a/server/src/main/java/org/opensearch/index/fielddata/plain/package-info.java b/server/src/main/java/org/opensearch/index/fielddata/plain/package-info.java
new file mode 100644
index 0000000000000..f719dfb72f842
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fielddata/plain/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all core field data operations */
+package org.opensearch.index.fielddata.plain;
diff --git a/server/src/main/java/org/opensearch/index/fieldvisitor/CustomFieldsVisitor.java b/server/src/main/java/org/opensearch/index/fieldvisitor/CustomFieldsVisitor.java
index 5be2fa5209ca5..df4d398b2b181 100644
--- a/server/src/main/java/org/opensearch/index/fieldvisitor/CustomFieldsVisitor.java
+++ b/server/src/main/java/org/opensearch/index/fieldvisitor/CustomFieldsVisitor.java
@@ -40,6 +40,8 @@
  * Supported pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy".
  * The Uid field is always loaded.
  * The class is optimized for source loading as it is a common use case.
+ *
+ * @opensearch.internal
  */
 public class CustomFieldsVisitor extends FieldsVisitor {
 
diff --git a/server/src/main/java/org/opensearch/index/fieldvisitor/FieldsVisitor.java b/server/src/main/java/org/opensearch/index/fieldvisitor/FieldsVisitor.java
index eb094ce1df9a4..91ca07d753cc6 100644
--- a/server/src/main/java/org/opensearch/index/fieldvisitor/FieldsVisitor.java
+++ b/server/src/main/java/org/opensearch/index/fieldvisitor/FieldsVisitor.java
@@ -34,8 +34,8 @@
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.StoredFieldVisitor;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -57,6 +57,8 @@
 
 /**
  * Base {@link StoredFieldVisitor} that retrieves all non-redundant metadata.
+ *
+ * @opensearch.internal
  */
 public class FieldsVisitor extends StoredFieldVisitor {
     private static final Set<String> BASE_REQUIRED_FIELDS = unmodifiableSet(newHashSet(IdFieldMapper.NAME, RoutingFieldMapper.NAME));
diff --git a/server/src/main/java/org/opensearch/index/fieldvisitor/IdOnlyFieldVisitor.java b/server/src/main/java/org/opensearch/index/fieldvisitor/IdOnlyFieldVisitor.java
index 67ec285f50cbf..b56026e0ffe49 100644
--- a/server/src/main/java/org/opensearch/index/fieldvisitor/IdOnlyFieldVisitor.java
+++ b/server/src/main/java/org/opensearch/index/fieldvisitor/IdOnlyFieldVisitor.java
@@ -37,6 +37,11 @@
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.Uid;
 
+/**
+ * Visitor pattern for doc ids only
+ *
+ * @opensearch.internal
+ */
 public final class IdOnlyFieldVisitor extends StoredFieldVisitor {
     private String id = null;
     private boolean visited = false;
diff --git a/server/src/main/java/org/opensearch/index/fieldvisitor/SingleFieldsVisitor.java b/server/src/main/java/org/opensearch/index/fieldvisitor/SingleFieldsVisitor.java
index 3214ec2780701..a7ce7b8f88384 100644
--- a/server/src/main/java/org/opensearch/index/fieldvisitor/SingleFieldsVisitor.java
+++ b/server/src/main/java/org/opensearch/index/fieldvisitor/SingleFieldsVisitor.java
@@ -33,15 +33,17 @@
 
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.StoredFieldVisitor;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.Uid;
-import org.apache.lucene.util.BytesRef;
 
 import java.util.List;
 
 /**
  * {@linkplain StoredFieldVisitor} that loads a single field value.
+ *
+ * @opensearch.internal
  */
 public final class SingleFieldsVisitor extends StoredFieldVisitor {
     private final MappedFieldType field;
diff --git a/server/src/main/java/org/opensearch/index/fieldvisitor/package-info.java b/server/src/main/java/org/opensearch/index/fieldvisitor/package-info.java
new file mode 100644
index 0000000000000..d6ab3f388c16a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/fieldvisitor/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** FieldVisitor classes for retrieving field values from lucene */
+package org.opensearch.index.fieldvisitor;
diff --git a/server/src/main/java/org/opensearch/index/flush/FlushStats.java b/server/src/main/java/org/opensearch/index/flush/FlushStats.java
index cfe28edf4c988..aec6e9199729d 100644
--- a/server/src/main/java/org/opensearch/index/flush/FlushStats.java
+++ b/server/src/main/java/org/opensearch/index/flush/FlushStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.flush;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Encapsulates statistics for flush
+ *
+ * @opensearch.internal
+ */
 public class FlushStats implements Writeable, ToXContentFragment {
 
     private long total;
@@ -120,6 +125,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for flush statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String FLUSH = "flush";
         static final String TOTAL = "total";
diff --git a/server/src/main/java/org/opensearch/index/flush/package-info.java b/server/src/main/java/org/opensearch/index/flush/package-info.java
new file mode 100644
index 0000000000000..c048eace8b798
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/flush/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing flush statistics */
+package org.opensearch.index.flush;
diff --git a/server/src/main/java/org/opensearch/index/get/GetResult.java b/server/src/main/java/org/opensearch/index/get/GetResult.java
index aa2bf43c5b290..7f87f9c61c93e 100644
--- a/server/src/main/java/org/opensearch/index/get/GetResult.java
+++ b/server/src/main/java/org/opensearch/index/get/GetResult.java
@@ -35,17 +35,18 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.SourceFieldMapper;
@@ -59,10 +60,15 @@
 import java.util.Objects;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 
+/**
+ * Result provided for a search get
+ *
+ * @opensearch.api
+ */
 public class GetResult implements Writeable, Iterable<DocumentField>, ToXContentObject {
 
     public static final String _INDEX = "_index";
@@ -213,7 +219,7 @@ public BytesReference sourceRef() {
         }
 
         try {
-            this.source = CompressorFactory.uncompressIfNeeded(this.source);
+            this.source = CompressorRegistry.uncompressIfNeeded(this.source);
             return this.source;
         } catch (IOException e) {
             throw new OpenSearchParseException("failed to decompress source", e);
@@ -488,6 +494,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/get/GetStats.java b/server/src/main/java/org/opensearch/index/get/GetStats.java
index fb37b5dfc6b42..5530a45717305 100644
--- a/server/src/main/java/org/opensearch/index/get/GetStats.java
+++ b/server/src/main/java/org/opensearch/index/get/GetStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.get;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats for a search get
+ *
+ * @opensearch.api
+ */
 public class GetStats implements Writeable, ToXContentFragment {
 
     private long existsCount;
@@ -140,6 +145,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for get statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String GET = "get";
         static final String TOTAL = "total";
diff --git a/server/src/main/java/org/opensearch/index/get/ShardGetService.java b/server/src/main/java/org/opensearch/index/get/ShardGetService.java
index e63d80336bc7a..546497a2e0d19 100644
--- a/server/src/main/java/org/opensearch/index/get/ShardGetService.java
+++ b/server/src/main/java/org/opensearch/index/get/ShardGetService.java
@@ -39,10 +39,10 @@
 import org.apache.lucene.index.IndexableFieldType;
 import org.apache.lucene.index.StoredFieldVisitor;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.index.VectorSimilarityFunction;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.lucene.uid.Versions;
@@ -50,10 +50,11 @@
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.Engine;
@@ -84,6 +85,11 @@
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 
+/**
+ * Gets an index shard
+ *
+ * @opensearch.internal
+ */
 public final class ShardGetService extends AbstractIndexShardComponent {
     private final MapperService mapperService;
     private final MeanMetric existsMetric = new MeanMetric();
@@ -216,25 +222,20 @@ private GetResult innerGet(
         fetchSourceContext = normalizeFetchSourceContent(fetchSourceContext, gFields);
 
         Term uidTerm = new Term(IdFieldMapper.NAME, Uid.encodeId(id));
-        Engine.GetResult get = indexShard.get(
-            new Engine.Get(realtime, true, id, uidTerm).version(version)
-                .versionType(versionType)
-                .setIfSeqNo(ifSeqNo)
-                .setIfPrimaryTerm(ifPrimaryTerm)
-        );
-        if (get.exists() == false) {
-            get.close();
-        }
-
-        if (get == null || get.exists() == false) {
-            return new GetResult(shardId.getIndexName(), id, UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM, -1, false, null, null, null);
-        }
 
-        try {
+        try (
+            Engine.GetResult get = indexShard.get(
+                new Engine.Get(realtime, true, id, uidTerm).version(version)
+                    .versionType(versionType)
+                    .setIfSeqNo(ifSeqNo)
+                    .setIfPrimaryTerm(ifPrimaryTerm)
+            )
+        ) {
+            if (get == null || get.exists() == false) {
+                return new GetResult(shardId.getIndexName(), id, UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM, -1, false, null, null, null);
+            }
             // break between having loaded it from translog (so we only have _source), and having a document to load
             return innerGetLoadFromStoredFields(id, gFields, fetchSourceContext, get, mapperService);
-        } finally {
-            get.close();
         }
     }
 
@@ -275,7 +276,7 @@ private GetResult innerGetLoadFromStoredFields(
         );
         if (fieldVisitor != null) {
             try {
-                docIdAndVersion.reader.document(docIdAndVersion.docId, fieldVisitor);
+                docIdAndVersion.reader.storedFields().document(docIdAndVersion.docId, fieldVisitor);
             } catch (IOException e) {
                 throw new OpenSearchException("Failed to get id [" + id + "]", e);
             }
@@ -298,7 +299,7 @@ private GetResult innerGetLoadFromStoredFields(
                         shardId.getIndexName(),
                         id,
                         source,
-                        XContentHelper.xContentType(source),
+                        MediaTypeRegistry.xContentType(source),
                         fieldVisitor.routing()
                     );
                     ParsedDocument doc = indexShard.mapperService().documentMapper().parse(sourceToParse);
@@ -326,6 +327,7 @@ private GetResult innerGetLoadFromStoredFields(
                                 0,
                                 0,
                                 0,
+                                VectorEncoding.FLOAT32,
                                 VectorSimilarityFunction.EUCLIDEAN,
                                 false
                             );
@@ -376,7 +378,7 @@ private GetResult innerGetLoadFromStoredFields(
                 sourceAsMap = typeMapTuple.v2();
                 sourceAsMap = XContentMapValues.filter(sourceAsMap, fetchSourceContext.includes(), fetchSourceContext.excludes());
                 try {
-                    source = BytesReference.bytes(XContentFactory.contentBuilder(sourceContentType).map(sourceAsMap));
+                    source = BytesReference.bytes(MediaTypeRegistry.contentBuilder(sourceContentType).map(sourceAsMap));
                 } catch (IOException e) {
                     throw new OpenSearchException("Failed to get id [" + id + "] with includes/excludes set", e);
                 }
@@ -404,7 +406,7 @@ private GetResult innerGetLoadFromStoredFields(
             sourceAsMap = typeMapTuple.v2();
             sourceAsMap = XContentMapValues.filter(sourceAsMap, fetchSourceContext.includes(), fetchSourceContext.excludes());
             try {
-                source = BytesReference.bytes(XContentFactory.contentBuilder(sourceContentType).map(sourceAsMap));
+                source = BytesReference.bytes(MediaTypeRegistry.contentBuilder(sourceContentType).map(sourceAsMap));
             } catch (IOException e) {
                 throw new OpenSearchException("Failed to get id [" + id + "] with includes/excludes set", e);
             }
diff --git a/server/src/main/java/org/opensearch/index/get/package-info.java b/server/src/main/java/org/opensearch/index/get/package-info.java
new file mode 100644
index 0000000000000..7a2f40441c1b5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/get/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing support Classes for Getting data from an Index */
+package org.opensearch.index.get;
diff --git a/server/src/main/java/org/opensearch/index/mapper/AbstractGeometryFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/AbstractGeometryFieldMapper.java
index 0d90e694ef481..a038cf178bb03 100644
--- a/server/src/main/java/org/opensearch/index/mapper/AbstractGeometryFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/AbstractGeometryFieldMapper.java
@@ -36,15 +36,15 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.search.Query;
 import org.opensearch.common.Explicit;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoJsonGeometryFormat;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.common.xcontent.support.MapXContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.search.lookup.SearchLookup;
@@ -62,14 +62,26 @@
 
 /**
  * Base field mapper class for all spatial field types
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractGeometryFieldMapper<Parsed, Processed> extends FieldMapper {
 
+    /**
+     * String parameter names for the base geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Names {
         public static final ParseField IGNORE_MALFORMED = new ParseField("ignore_malformed");
         public static final ParseField IGNORE_Z_VALUE = new ParseField("ignore_z_value");
     }
 
+    /**
+     * Default parameters for the base geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final Explicit<Boolean> IGNORE_MALFORMED = new Explicit<>(false, false);
         public static final Explicit<Boolean> IGNORE_Z_VALUE = new Explicit<>(true, false);
@@ -84,6 +96,8 @@ public static class Defaults {
 
     /**
      * Interface representing an preprocessor in geometry indexing pipeline
+     *
+     * @opensearch.internal
      */
     public interface Indexer<Parsed, Processed> {
         Processed prepareForIndexing(Parsed geometry);
@@ -95,6 +109,8 @@ public interface Indexer<Parsed, Processed> {
 
     /**
      * Interface representing parser in geometry indexing pipeline.
+     *
+     * @opensearch.internal
      */
     public abstract static class Parser<Parsed> {
         /**
@@ -125,7 +141,7 @@ public Object parseAndFormatObject(Object value, String format) {
                     NamedXContentRegistry.EMPTY,
                     LoggingDeprecationHandler.INSTANCE,
                     Collections.singletonMap("dummy_field", value),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             ) {
                 parser.nextToken(); // start object
@@ -141,6 +157,11 @@ public Object parseAndFormatObject(Object value, String format) {
         }
     }
 
+    /**
+     * Builder for the base geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder<T extends Builder<T, FT>, FT extends AbstractGeometryFieldType> extends FieldMapper.Builder<T> {
         protected Boolean ignoreMalformed;
         protected Boolean ignoreZValue;
@@ -198,6 +219,11 @@ public Builder ignoreZValue(final boolean ignoreZValue) {
         }
     }
 
+    /**
+     * Base type parser for geometry field mappers
+     *
+     * @opensearch.internal
+     */
     public abstract static class TypeParser<T extends Builder> implements Mapper.TypeParser {
         protected abstract T newBuilder(String name, Map<String, Object> params);
 
@@ -234,13 +260,23 @@ public T parse(String name, Map<String, Object> node, Map<String, Object> params
             return builder;
         }
 
+        /**
+         * Parse the node with the field name as name; using various parse methods for different attributes.
+         */
         @Override
         public T parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
-            Map<String, Object> params = new HashMap<>();
-            return parse(name, node, params, parserContext);
+            final T builder = parse(name, node, new HashMap<>(), parserContext);
+            // parse the common attributes(like doc_values, boosts etc.) and set them in the builder.
+            TypeParsers.parseField(builder, name, node, parserContext);
+            return builder;
         }
     }
 
+    /**
+     * Base field type for all geometry fields
+     *
+     * @opensearch.internal
+     */
     public abstract static class AbstractGeometryFieldType<Parsed, Processed> extends MappedFieldType {
 
         protected Indexer<Parsed, Processed> geometryIndexer;
diff --git a/server/src/main/java/org/opensearch/index/mapper/AbstractPointGeometryFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/AbstractPointGeometryFieldMapper.java
index 19e3a5073fd8c..1f53490de1ce1 100644
--- a/server/src/main/java/org/opensearch/index/mapper/AbstractPointGeometryFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/AbstractPointGeometryFieldMapper.java
@@ -35,13 +35,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.CheckedBiFunction;
 import org.opensearch.common.Explicit;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeometryFormat;
 import org.opensearch.common.geo.GeometryParser;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.Point;
 
@@ -56,9 +56,18 @@
 
 import static org.opensearch.index.mapper.TypeParsers.parseField;
 
-/** Base class for for spatial fields that only support indexing points */
+/**
+ * Base class for spatial fields that only support indexing points
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractPointGeometryFieldMapper<Parsed, Processed> extends AbstractGeometryFieldMapper<Parsed, Processed> {
 
+    /**
+     * Common parameter names for the base point geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Names extends AbstractGeometryFieldMapper.Names {
         public static final ParseField NULL_VALUE = new ParseField("null_value");
     }
@@ -70,6 +79,11 @@ public static class Names extends AbstractGeometryFieldMapper.Names {
         DEFAULT_FIELD_TYPE.freeze();
     }
 
+    /**
+     * Base builder for the base point geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder<T extends Builder<T, FT>, FT extends AbstractPointGeometryFieldType> extends
         AbstractGeometryFieldMapper.Builder<T, FT> {
 
@@ -109,6 +123,11 @@ public AbstractPointGeometryFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * Base type parser for the base point geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class TypeParser<T extends Builder> extends AbstractGeometryFieldMapper.TypeParser<Builder> {
         protected abstract ParsedPoint parseNullValue(Object nullValue, boolean ignoreZValue, boolean ignoreMalformed);
 
@@ -140,6 +159,11 @@ public T parse(String name, Map<String, Object> node, Map<String, Object> params
 
     ParsedPoint nullValue;
 
+    /**
+     * Base field type for the base point geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class AbstractPointGeometryFieldType<Parsed, Processed> extends AbstractGeometryFieldType<Parsed, Processed> {
         protected AbstractPointGeometryFieldType(
             String name,
@@ -193,7 +217,11 @@ public ParsedPoint nullValue() {
         return nullValue;
     }
 
-    /** represents a Point that has been parsed by {@link PointParser} */
+    /**
+     * represents a Point that has been parsed by {@link PointParser}
+     *
+     * @opensearch.internal
+     */
     public interface ParsedPoint {
         void validate(String fieldName);
 
@@ -208,7 +236,11 @@ default boolean isNormalizable(double coord) {
         }
     }
 
-    /** A parser implementation that can parse the various point formats */
+    /**
+     * A parser implementation that can parse the various point formats
+     *
+     * @opensearch.internal
+     */
     public static class PointParser<P extends ParsedPoint> extends Parser<List<P>> {
         /**
          * Note that this parser is only used for formatting values.
diff --git a/server/src/main/java/org/opensearch/index/mapper/AbstractShapeGeometryFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/AbstractShapeGeometryFieldMapper.java
index 56ef58f1b92e9..186e01047dc7d 100644
--- a/server/src/main/java/org/opensearch/index/mapper/AbstractShapeGeometryFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/AbstractShapeGeometryFieldMapper.java
@@ -33,12 +33,12 @@
 
 import org.apache.lucene.document.FieldType;
 import org.opensearch.common.Explicit;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder.Orientation;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.LegacyGeoShapeFieldMapper.DeprecatedParameters;
 
 import java.io.IOException;
@@ -48,19 +48,36 @@
 
 /**
  * Base class for {@link GeoShapeFieldMapper} and {@link LegacyGeoShapeFieldMapper}
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractShapeGeometryFieldMapper<Parsed, Processed> extends AbstractGeometryFieldMapper<Parsed, Processed> {
 
+    /**
+     * Common parameters for the base shape geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Names extends AbstractGeometryFieldMapper.Names {
         public static final ParseField ORIENTATION = new ParseField("orientation");
         public static final ParseField COERCE = new ParseField("coerce");
     }
 
+    /**
+     * Parameter defaults for the base shape geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Defaults extends AbstractGeometryFieldMapper.Defaults {
         public static final Explicit<Orientation> ORIENTATION = new Explicit<>(Orientation.RIGHT, false);
         public static final Explicit<Boolean> COERCE = new Explicit<>(false, false);
     }
 
+    /**
+     * Base builder for the base shape geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder<T extends Builder<T, FT>, FT extends AbstractShapeGeometryFieldType> extends
         AbstractGeometryFieldMapper.Builder<T, FT> {
         protected Boolean coerce;
@@ -122,6 +139,11 @@ protected Explicit<Orientation> orientation() {
 
     protected static final String DEPRECATED_PARAMETERS_KEY = "deprecated_parameters";
 
+    /**
+     * Base type parser for the base shape geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class TypeParser extends AbstractGeometryFieldMapper.TypeParser<Builder> {
         protected abstract Builder newBuilder(String name, Map<String, Object> params);
 
@@ -178,6 +200,11 @@ public Builder parse(String name, Map<String, Object> node, Map<String, Object>
         }
     }
 
+    /**
+     * Base field type for the base shape geometry field mapper
+     *
+     * @opensearch.internal
+     */
     public abstract static class AbstractShapeGeometryFieldType<Parsed, Processed> extends AbstractGeometryFieldType<Parsed, Processed> {
         protected Orientation orientation = Defaults.ORIENTATION.value();
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/AllFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/AllFieldMapper.java
deleted file mode 100644
index 634424d6f45a4..0000000000000
--- a/server/src/main/java/org/opensearch/index/mapper/AllFieldMapper.java
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.mapper;
-
-import org.apache.lucene.document.FieldType;
-import org.apache.lucene.index.IndexOptions;
-import org.apache.lucene.search.MatchNoDocsQuery;
-import org.apache.lucene.search.Query;
-import org.opensearch.common.Explicit;
-import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.search.lookup.SearchLookup;
-
-import java.util.Collections;
-import java.util.List;
-
-/**
- * Noop mapper that ensures that mappings created in 6x that explicitly disable the _all field
- * can be restored in this version.
- *
- * TODO: Remove in 8
- */
-public class AllFieldMapper extends MetadataFieldMapper {
-    public static final String NAME = "_all";
-    public static final String CONTENT_TYPE = "_all";
-
-    public static class Defaults {
-        public static final FieldType FIELD_TYPE = new FieldType();
-
-        static {
-            FIELD_TYPE.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS);
-            FIELD_TYPE.setTokenized(true);
-            FIELD_TYPE.freeze();
-        }
-    }
-
-    private static AllFieldMapper toType(FieldMapper in) {
-        return (AllFieldMapper) in;
-    }
-
-    public static class Builder extends MetadataFieldMapper.Builder {
-
-        private final Parameter<Explicit<Boolean>> enabled = updateableBoolParam("enabled", m -> toType(m).enabled, false);
-
-        public Builder() {
-            super(NAME);
-        }
-
-        @Override
-        protected List<Parameter<?>> getParameters() {
-            return Collections.singletonList(enabled);
-        }
-
-        @Override
-        public AllFieldMapper build(BuilderContext context) {
-            if (enabled.getValue().value()) {
-                throw new IllegalArgumentException("[_all] is disabled in this version.");
-            }
-            return new AllFieldMapper(enabled.getValue());
-        }
-    }
-
-    public static final TypeParser PARSER = new ConfigurableTypeParser(
-        c -> new AllFieldMapper(new Explicit<>(false, false)),
-        c -> new Builder()
-    );
-
-    static final class AllFieldType extends StringFieldType {
-        AllFieldType() {
-            super(NAME, false, false, false, TextSearchInfo.NONE, Collections.emptyMap());
-        }
-
-        @Override
-        public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchLookup, String format) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public String typeName() {
-            return CONTENT_TYPE;
-        }
-
-        @Override
-        public Query existsQuery(QueryShardContext context) {
-            return new MatchNoDocsQuery();
-        }
-    }
-
-    private final Explicit<Boolean> enabled;
-
-    private AllFieldMapper(Explicit<Boolean> enabled) {
-        super(new AllFieldType());
-        this.enabled = enabled;
-    }
-
-    @Override
-    protected String contentType() {
-        return CONTENT_TYPE;
-    }
-
-    @Override
-    public ParametrizedFieldMapper.Builder getMergeBuilder() {
-        return new Builder().init(this);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/index/mapper/ArraySourceValueFetcher.java b/server/src/main/java/org/opensearch/index/mapper/ArraySourceValueFetcher.java
index f28e4a64eec6e..f5dc34ab8ac5d 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ArraySourceValueFetcher.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ArraySourceValueFetcher.java
@@ -47,6 +47,8 @@
  * This class differs from {@link SourceValueFetcher} in that it directly handles
  * array values in parsing. Field types should use this class if their corresponding
  * mapper returns true for {@link FieldMapper#parsesArrayValue()}.
+ *
+ * @opensearch.internal
  */
 public abstract class ArraySourceValueFetcher implements ValueFetcher {
     private final Set<String> sourcePaths;
@@ -72,7 +74,7 @@ public List<Object> fetchValues(SourceLookup lookup) {
         for (String path : sourcePaths) {
             Object sourceValue = lookup.extractValue(path, nullValue);
             if (sourceValue == null) {
-                return org.opensearch.common.collect.List.of();
+                return List.of();
             }
             values.addAll((List<?>) parseSourceValue(sourceValue));
         }
diff --git a/server/src/main/java/org/opensearch/index/mapper/BinaryFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/BinaryFieldMapper.java
index 68b0df63f2bef..040491f775357 100644
--- a/server/src/main/java/org/opensearch/index/mapper/BinaryFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/BinaryFieldMapper.java
@@ -32,16 +32,17 @@
 
 package org.opensearch.index.mapper;
 
-import com.carrotsearch.hppc.ObjectArrayList;
+import org.apache.lucene.document.InvertableType;
 import org.apache.lucene.document.StoredField;
+import org.apache.lucene.document.StoredValue;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.plain.BytesBinaryIndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
@@ -52,6 +53,7 @@
 
 import java.io.IOException;
 import java.time.ZoneId;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Base64;
 import java.util.Collections;
@@ -59,6 +61,11 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
+/**
+ * A mapper for binary fields
+ *
+ * @opensearch.internal
+ */
 public class BinaryFieldMapper extends ParametrizedFieldMapper {
 
     public static final String CONTENT_TYPE = "binary";
@@ -67,6 +74,11 @@ private static BinaryFieldMapper toType(FieldMapper in) {
         return (BinaryFieldMapper) in;
     }
 
+    /**
+     * Builder for the binary field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> stored = Parameter.storeParam(m -> toType(m).stored, false);
@@ -101,6 +113,11 @@ public BinaryFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n));
 
+    /**
+     * Binary field type
+     *
+     * @opensearch.internal
+     */
     public static final class BinaryFieldType extends MappedFieldType {
 
         private BinaryFieldType(String name, boolean isStored, boolean hasDocValues, Map<String, String> meta) {
@@ -218,41 +235,59 @@ protected String contentType() {
         return CONTENT_TYPE;
     }
 
+    /**
+     * Custom binary doc values field for the binary field mapper
+     *
+     * @opensearch.internal
+     */
     public static class CustomBinaryDocValuesField extends CustomDocValuesField {
 
-        private final ObjectArrayList<byte[]> bytesList;
-
-        private int totalSize = 0;
+        // We considered using a TreeSet instead of an ArrayList here.
+        // Benchmarks show that ArrayList performs much better
+        // For details, see: https://github.com/opensearch-project/OpenSearch/pull/9426
+        // Benchmarks are in CustomBinaryDocValuesFiledBenchmark
+        private final ArrayList<byte[]> bytesList;
 
         public CustomBinaryDocValuesField(String name, byte[] bytes) {
             super(name);
-            bytesList = new ObjectArrayList<>();
+            bytesList = new ArrayList<>();
             add(bytes);
         }
 
         public void add(byte[] bytes) {
             bytesList.add(bytes);
-            totalSize += bytes.length;
         }
 
         @Override
         public BytesRef binaryValue() {
             try {
-                CollectionUtils.sortAndDedup(bytesList);
-                int size = bytesList.size();
-                BytesStreamOutput out = new BytesStreamOutput(totalSize + (size + 1) * 5);
-                out.writeVInt(size);  // write total number of values
-                for (int i = 0; i < size; i++) {
-                    final byte[] value = bytesList.get(i);
-                    int valueLength = value.length;
-                    out.writeVInt(valueLength);
-                    out.writeBytes(value, 0, valueLength);
+                // sort and dedup in place
+                CollectionUtils.sortAndDedup(bytesList, Arrays::compareUnsigned);
+                int size = bytesList.stream().map(b -> b.length).reduce(0, Integer::sum);
+                int length = bytesList.size();
+                try (BytesStreamOutput out = new BytesStreamOutput(size + (length + 1) * 5)) {
+                    out.writeVInt(length);  // write total number of values
+                    for (byte[] value : bytesList) {
+                        int valueLength = value.length;
+                        out.writeVInt(valueLength);
+                        out.writeBytes(value, 0, valueLength);
+                    }
+                    return out.bytes().toBytesRef();
                 }
-                return out.bytes().toBytesRef();
             } catch (IOException e) {
                 throw new OpenSearchException("Failed to get binary value", e);
             }
 
         }
+
+        @Override
+        public StoredValue storedValue() {
+            return null;
+        }
+
+        @Override
+        public InvertableType invertableType() {
+            return InvertableType.BINARY;
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/mapper/BinaryRangeUtil.java b/server/src/main/java/org/opensearch/index/mapper/BinaryRangeUtil.java
index 96744ba2d01d8..7a07df7d217df 100644
--- a/server/src/main/java/org/opensearch/index/mapper/BinaryRangeUtil.java
+++ b/server/src/main/java/org/opensearch/index/mapper/BinaryRangeUtil.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.BytesStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -47,6 +47,11 @@
 import java.util.List;
 import java.util.Set;
 
+/**
+ * Utility class for binary ranges
+ *
+ * @opensearch.internal
+ */
 final class BinaryRangeUtil {
 
     private BinaryRangeUtil() {};
diff --git a/server/src/main/java/org/opensearch/index/mapper/BooleanFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/BooleanFieldMapper.java
index a14364640d6ee..22eeed205e2c8 100644
--- a/server/src/main/java/org/opensearch/index/mapper/BooleanFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/BooleanFieldMapper.java
@@ -42,8 +42,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData.NumericType;
 import org.opensearch.index.fielddata.plain.SortedNumericIndexFieldData;
@@ -61,11 +61,18 @@
 
 /**
  * A field mapper for boolean fields.
+ *
+ * @opensearch.internal
  */
 public class BooleanFieldMapper extends ParametrizedFieldMapper {
 
     public static final String CONTENT_TYPE = "boolean";
 
+    /**
+     * Default parameters for the boolean field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final FieldType FIELD_TYPE = new FieldType();
 
@@ -77,6 +84,11 @@ public static class Defaults {
         }
     }
 
+    /**
+     * Values that can be used for this field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Values {
         public static final BytesRef TRUE = new BytesRef("T");
         public static final BytesRef FALSE = new BytesRef("F");
@@ -86,6 +98,11 @@ private static BooleanFieldMapper toType(FieldMapper in) {
         return (BooleanFieldMapper) in;
     }
 
+    /**
+     * Builder for this field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> docValues = Parameter.docValuesParam(m -> toType(m).hasDocValues, true);
@@ -129,6 +146,11 @@ public BooleanFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n));
 
+    /**
+     * Field type for boolean field mapper
+     *
+     * @opensearch.internal
+     */
     public static final class BooleanFieldType extends TermBasedFieldType {
 
         private final Boolean nullValue;
diff --git a/server/src/main/java/org/opensearch/index/mapper/CompletionFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/CompletionFieldMapper.java
index 2d0f59fc76ea4..90ef3cc1689a4 100644
--- a/server/src/main/java/org/opensearch/index/mapper/CompletionFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/CompletionFieldMapper.java
@@ -44,14 +44,14 @@
 import org.apache.lucene.search.suggest.document.SuggestField;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.NumberType;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.NumberType;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.query.QueryShardContext;
@@ -90,6 +90,8 @@
  *  against the weighted FST index by the {@link CompletionSuggester}.
  *  This field can also be extended to add search criteria to suggestions
  *  for query-time filtering and boosting (see {@link ContextMappings}
+ *
+ *  @opensearch.internal
  */
 public class CompletionFieldMapper extends ParametrizedFieldMapper {
     public static final String CONTENT_TYPE = "completion";
@@ -104,6 +106,11 @@ public ParametrizedFieldMapper.Builder getMergeBuilder() {
         return new Builder(simpleName(), defaultAnalyzer, indexVersionCreated).init(this);
     }
 
+    /**
+     * Default parameters
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final FieldType FIELD_TYPE = new FieldType();
         static {
@@ -119,6 +126,11 @@ public static class Defaults {
         public static final int DEFAULT_MAX_INPUT_LENGTH = 50;
     }
 
+    /**
+     * Parameter fields
+     *
+     * @opensearch.internal
+     */
     public static class Fields {
         // Content field names
         public static final String CONTENT_FIELD_NAME_INPUT = "input";
@@ -132,6 +144,8 @@ private static CompletionFieldMapper toType(FieldMapper in) {
 
     /**
      * Builder for {@link CompletionFieldMapper}
+     *
+     * @opensearch.internal
      */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
@@ -253,6 +267,11 @@ private void checkCompletionContextsLimit(BuilderContext context) {
         (n, c) -> new Builder(n, c.getIndexAnalyzers().get("simple"), c.indexVersionCreated())
     );
 
+    /**
+     * Field type for Completion Field Mapper
+     *
+     * @opensearch.internal
+     */
     public static final class CompletionFieldType extends TermBasedFieldType {
 
         private static PostingsFormat postingsFormat;
@@ -606,6 +625,11 @@ private void parse(ParseContext parseContext, Token token, XContentParser parser
         }
     }
 
+    /**
+     * Metadata for completion input
+     *
+     * @opensearch.internal
+     */
     static class CompletionInputMetadata {
         public final String input;
         public final Map<String, Set<String>> contexts;
diff --git a/server/src/main/java/org/opensearch/index/mapper/ConstantFieldType.java b/server/src/main/java/org/opensearch/index/mapper/ConstantFieldType.java
index 4dec612ceff75..a28a6369b1aa4 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ConstantFieldType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ConstantFieldType.java
@@ -51,6 +51,8 @@
  * cheap. In particular they should not read data from disk or perform a
  * network call. Furthermore they may only return a {@link MatchAllDocsQuery}
  * or a {@link MatchNoDocsQuery}.
+ *
+ * @opensearch.internal
  */
 public abstract class ConstantFieldType extends MappedFieldType {
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/ContentPath.java b/server/src/main/java/org/opensearch/index/mapper/ContentPath.java
index 951a0bc0f9890..8b0d5e24056d3 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ContentPath.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ContentPath.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.index.mapper;
 
+/**
+ * JSON Path for a document / field
+ *
+ * @opensearch.internal
+ */
 public final class ContentPath {
 
     private static final char DELIMITER = '.';
@@ -79,6 +84,9 @@ public void remove() {
     }
 
     public String pathAsText(String name) {
+        if (offset == index) {
+            return name;
+        }
         sb.setLength(0);
         for (int i = offset; i < index; i++) {
             sb.append(path[i]).append(DELIMITER);
diff --git a/server/src/main/java/org/opensearch/index/mapper/CustomDocValuesField.java b/server/src/main/java/org/opensearch/index/mapper/CustomDocValuesField.java
index 664ee45c091bb..2776e7515bbf6 100644
--- a/server/src/main/java/org/opensearch/index/mapper/CustomDocValuesField.java
+++ b/server/src/main/java/org/opensearch/index/mapper/CustomDocValuesField.java
@@ -41,7 +41,13 @@
 
 import java.io.Reader;
 
-// used for binary, geo and range fields
+/**
+ * Base class for constructing a custom docvalues type
+ *
+ * used for binary, geo, and range fields
+ *
+ * @opensearch.api
+ */
 public abstract class CustomDocValuesField implements IndexableField {
 
     public static final FieldType TYPE = new FieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/DataStreamFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/DataStreamFieldMapper.java
index 03e792c4893d4..4d03d5f67e7d5 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DataStreamFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DataStreamFieldMapper.java
@@ -22,16 +22,31 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Field mapper for a datastream field
+ *
+ * @opensearch.internal
+ */
 public class DataStreamFieldMapper extends MetadataFieldMapper {
 
     public static final String NAME = "_data_stream_timestamp";
     public static final String CONTENT_TYPE = "_data_stream_timestamp";
 
+    /**
+     * Default parameters
+     *
+     * @opensearch.internal
+     */
     public static final class Defaults {
         public static final boolean ENABLED = false;
         public static final TimestampField TIMESTAMP_FIELD = new TimestampField("@timestamp");
     }
 
+    /**
+     * Builder for the field mapper
+     *
+     * @opensearch.internal
+     */
     public static final class Builder extends MetadataFieldMapper.Builder {
         final Parameter<Boolean> enabledParam = Parameter.boolParam("enabled", false, mapper -> toType(mapper).enabled, Defaults.ENABLED);
 
@@ -58,6 +73,11 @@ public MetadataFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * Field type for data stream field mapper
+     *
+     * @opensearch.internal
+     */
     public static final class DataStreamFieldType extends MappedFieldType {
         public static final DataStreamFieldType INSTANCE = new DataStreamFieldType();
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/DateFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/DateFieldMapper.java
index e2239069603e6..d9b26cce3735c 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DateFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DateFieldMapper.java
@@ -37,9 +37,9 @@
 import org.apache.lucene.document.StoredField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.PointValues;
-import org.apache.lucene.sandbox.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
+import org.apache.lucene.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
@@ -68,8 +68,8 @@
 import java.time.Instant;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
-import java.util.Arrays;
 import java.time.ZonedDateTime;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -81,7 +81,11 @@
 
 import static org.opensearch.common.time.DateUtils.toLong;
 
-/** A {@link FieldMapper} for dates. */
+/**
+ * A {@link FieldMapper} for dates.
+ *
+ * @opensearch.internal
+ */
 public final class DateFieldMapper extends ParametrizedFieldMapper {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(DateFieldMapper.class);
@@ -90,6 +94,11 @@ public final class DateFieldMapper extends ParametrizedFieldMapper {
     public static final String DATE_NANOS_CONTENT_TYPE = "date_nanos";
     public static final DateFormatter DEFAULT_DATE_TIME_FORMATTER = DateFormatter.forPattern("strict_date_optional_time||epoch_millis");
 
+    /**
+     * Resolution of the date time
+     *
+     * @opensearch.internal
+     */
     public enum Resolution {
         MILLISECONDS(CONTENT_TYPE, NumericType.DATE) {
             @Override
@@ -197,6 +206,11 @@ private static DateFieldMapper toType(FieldMapper in) {
         return (DateFieldMapper) in;
     }
 
+    /**
+     * Builder for the date field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> index = Parameter.indexParam(m -> toType(m).indexed, true);
@@ -308,6 +322,11 @@ public DateFieldMapper build(BuilderContext context) {
         return new Builder(n, Resolution.NANOSECONDS, c.getDateFormatter(), ignoreMalformedByDefault, c.indexVersionCreated());
     });
 
+    /**
+     * Field type for date field mapper
+     *
+     * @opensearch.internal
+     */
     public static final class DateFieldType extends MappedFieldType {
         protected final DateFormatter dateTimeFormatter;
         protected final DateMathParser dateMathParser;
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocCountFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/DocCountFieldMapper.java
new file mode 100644
index 0000000000000..0a461fff38fac
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/mapper/DocCountFieldMapper.java
@@ -0,0 +1,164 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.search.DocValuesFieldExistsQuery;
+import org.apache.lucene.search.Query;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.query.QueryShardException;
+import org.opensearch.search.lookup.SearchLookup;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Mapper for the doc_count field.
+ *
+ * @opensearch.internal
+ */
+public class DocCountFieldMapper extends MetadataFieldMapper {
+
+    public static final String NAME = "_doc_count";
+    public static final String CONTENT_TYPE = "_doc_count";
+
+    public static final TypeParser PARSER = new ConfigurableTypeParser(
+        c -> new DocCountFieldMapper(),
+        c -> new DocCountFieldMapper.Builder()
+    );
+
+    static class Builder extends MetadataFieldMapper.Builder {
+
+        Builder() {
+            super(NAME);
+        }
+
+        @Override
+        protected List<Parameter<?>> getParameters() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public DocCountFieldMapper build(BuilderContext context) {
+            return new DocCountFieldMapper();
+        }
+    }
+
+    /**
+     * Field type for DocCount Field Mapper
+     *
+     * @opensearch.internal
+     */
+    public static final class DocCountFieldType extends MappedFieldType {
+
+        public static final DocCountFieldType INSTANCE = new DocCountFieldType();
+
+        private static final Long defaultValue = 1L;
+
+        public DocCountFieldType() {
+            super(NAME, false, false, true, TextSearchInfo.NONE, Collections.emptyMap());
+        }
+
+        @Override
+        public String typeName() {
+            return CONTENT_TYPE;
+        }
+
+        @Override
+        public String familyTypeName() {
+            return NumberFieldMapper.NumberType.LONG.typeName();
+        }
+
+        @Override
+        public Query existsQuery(QueryShardContext context) {
+            return new DocValuesFieldExistsQuery(NAME);
+        }
+
+        @Override
+        public Query termQuery(Object value, QueryShardContext context) {
+            throw new QueryShardException(context, "Field [" + name() + "] of type [" + typeName() + "] is not searchable");
+        }
+
+        @Override
+        public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchLookup, String format) {
+            if (format != null) {
+                throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+            }
+
+            return new SourceValueFetcher(name(), context, defaultValue) {
+                @Override
+                protected Object parseSourceValue(Object value) {
+                    if ("".equals(value)) {
+                        return defaultValue;
+                    } else {
+                        return NumberFieldMapper.NumberType.objectToLong(value, false);
+                    }
+                }
+            };
+        }
+    }
+
+    private DocCountFieldMapper() {
+        super(DocCountFieldType.INSTANCE);
+    }
+
+    @Override
+    protected void parseCreateField(ParseContext context) throws IOException {
+        XContentParser parser = context.parser();
+        XContentParserUtils.ensureExpectedToken(XContentParser.Token.VALUE_NUMBER, parser.currentToken(), parser);
+
+        long value = parser.longValue(false);
+        if (value <= 0) {
+            throw new IllegalArgumentException("Field [" + fieldType().name() + "] must be a positive integer.");
+        }
+        final Field docCount = new NumericDocValuesField(NAME, value);
+        context.doc().add(docCount);
+    }
+
+    @Override
+    public void preParse(ParseContext context) {}
+
+    @Override
+    public DocCountFieldType fieldType() {
+        return (DocCountFieldType) super.fieldType();
+    }
+
+    @Override
+    protected String contentType() {
+        return CONTENT_TYPE;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocValueFetcher.java b/server/src/main/java/org/opensearch/index/mapper/DocValueFetcher.java
index e97a4cd636197..bf14af809fbfd 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DocValueFetcher.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DocValueFetcher.java
@@ -45,6 +45,8 @@
 
 /**
  * Value fetcher that loads from doc values.
+ *
+ * @opensearch.internal
  */
 public final class DocValueFetcher implements ValueFetcher {
     private final DocValueFormat format;
@@ -72,6 +74,11 @@ public List<Object> fetchValues(SourceLookup lookup) throws IOException {
         return result;
     }
 
+    /**
+     * Leaf interface
+     *
+     * @opensearch.internal
+     */
     public interface Leaf {
         /**
          * Advance the doc values reader to the provided doc.
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocumentMapper.java b/server/src/main/java/org/opensearch/index/mapper/DocumentMapper.java
index 0ee0a3cb9a180..0a22497d416e6 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DocumentMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DocumentMapper.java
@@ -41,14 +41,14 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchGenerationException;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.mapper.MapperService.MergeReason;
@@ -63,8 +63,18 @@
 import java.util.Objects;
 import java.util.stream.Stream;
 
+/**
+ * The OpenSearch DocumentMapper
+ *
+ * @opensearch.internal
+ */
 public class DocumentMapper implements ToXContentFragment {
 
+    /**
+     * Builder for the Document Field Mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
 
         private final Map<Class<? extends MetadataFieldMapper>, MetadataFieldMapper> metadataMappers = new LinkedHashMap<>();
@@ -161,7 +171,6 @@ public DocumentMapper(MapperService mapperService, Mapping mapping) {
         final Collection<String> deleteTombstoneMetadataFields = Arrays.asList(
             VersionFieldMapper.NAME,
             IdFieldMapper.NAME,
-            TypeFieldMapper.NAME,
             SeqNoFieldMapper.NAME,
             SeqNoFieldMapper.PRIMARY_TERM_NAME,
             SeqNoFieldMapper.TOMBSTONE_NAME
@@ -245,13 +254,13 @@ public ParsedDocument parse(SourceToParse source) throws MapperParsingException
     }
 
     public ParsedDocument createDeleteTombstoneDoc(String index, String id) throws MapperParsingException {
-        final SourceToParse emptySource = new SourceToParse(index, id, new BytesArray("{}"), XContentType.JSON);
+        final SourceToParse emptySource = new SourceToParse(index, id, new BytesArray("{}"), MediaTypeRegistry.JSON);
         return documentParser.parseDocument(emptySource, deleteTombstoneMetadataFieldMappers).toTombstone();
     }
 
     public ParsedDocument createNoopTombstoneDoc(String index, String reason) throws MapperParsingException {
         final String id = ""; // _id won't be used.
-        final SourceToParse sourceToParse = new SourceToParse(index, id, new BytesArray("{}"), XContentType.JSON);
+        final SourceToParse sourceToParse = new SourceToParse(index, id, new BytesArray("{}"), MediaTypeRegistry.JSON);
         final ParsedDocument parsedDoc = documentParser.parseDocument(sourceToParse, noopTombstoneMetadataFieldMappers).toTombstone();
         // Store the reason of a noop as a raw string in the _source field
         final BytesRef byteRef = new BytesRef(reason);
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocumentMapperForType.java b/server/src/main/java/org/opensearch/index/mapper/DocumentMapperForType.java
index dd92cdfacef64..b26c3f3645433 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DocumentMapperForType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DocumentMapperForType.java
@@ -32,6 +32,14 @@
 
 package org.opensearch.index.mapper;
 
+/**
+ * Document mapper used for types
+ *
+ * @opensearch.internal
+ *
+ * @deprecated types are being removed
+ */
+@Deprecated
 public class DocumentMapperForType {
     private final DocumentMapper documentMapper;
     private final Mapping mapping;
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocumentMapperParser.java b/server/src/main/java/org/opensearch/index/mapper/DocumentMapperParser.java
index 2d6880c6b4186..8b0af72ba0852 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DocumentMapperParser.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DocumentMapperParser.java
@@ -38,10 +38,11 @@
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.similarity.SimilarityService;
@@ -55,6 +56,11 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Parser for a document mapper
+ *
+ * @opensearch.internal
+ */
 public class DocumentMapperParser {
 
     final MapperService mapperService;
@@ -116,7 +122,7 @@ public Mapper.TypeParser.ParserContext parserContext(DateFormatter dateFormatter
     public DocumentMapper parse(@Nullable String type, CompressedXContent source) throws MapperParsingException {
         Map<String, Object> mapping = null;
         if (source != null) {
-            Map<String, Object> root = XContentHelper.convertToMap(source.compressedReference(), true, XContentType.JSON).v2();
+            Map<String, Object> root = XContentHelper.convertToMap(source.compressedReference(), true, MediaTypeRegistry.JSON).v2();
             Tuple<String, Map<String, Object>> t = extractMapping(type, root);
             type = t.v1();
             mapping = t.v2();
diff --git a/server/src/main/java/org/opensearch/index/mapper/DocumentParser.java b/server/src/main/java/org/opensearch/index/mapper/DocumentParser.java
index bcafddd6d5816..f276d6ee2e579 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DocumentParser.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DocumentParser.java
@@ -36,14 +36,15 @@
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DynamicTemplate.XContentFieldType;
 
@@ -56,7 +57,11 @@
 
 import static org.opensearch.index.mapper.FieldMapper.IGNORE_MALFORMED_SETTING;
 
-/** A parser for documents, given mappings from a DocumentMapper */
+/**
+ * A parser for documents, given mappings from a DocumentMapper
+ *
+ * @opensearch.internal
+ */
 final class DocumentParser {
 
     private final IndexSettings indexSettings;
@@ -72,14 +77,14 @@ final class DocumentParser {
     ParsedDocument parseDocument(SourceToParse source, MetadataFieldMapper[] metadataFieldsMappers) throws MapperParsingException {
         final Mapping mapping = docMapper.mapping();
         final ParseContext.InternalParseContext context;
-        final XContentType xContentType = source.getXContentType();
+        final MediaType mediaType = source.getMediaType();
 
         try (
             XContentParser parser = XContentHelper.createParser(
                 docMapperParser.getXContentRegistry(),
                 LoggingDeprecationHandler.INSTANCE,
                 source.source(),
-                xContentType
+                mediaType
             )
         ) {
             context = new ParseContext.InternalParseContext(indexSettings, docMapperParser, docMapper, source, parser);
@@ -178,7 +183,7 @@ private static ParsedDocument parsedDocument(SourceToParse source, ParseContext.
             source.routing(),
             context.docs(),
             context.sourceToParse().source(),
-            context.sourceToParse().getXContentType(),
+            context.sourceToParse().getMediaType(),
             update
         );
     }
@@ -421,55 +426,63 @@ private static void innerParseObject(
         String currentFieldName,
         XContentParser.Token token
     ) throws IOException {
-        assert token == XContentParser.Token.FIELD_NAME || token == XContentParser.Token.END_OBJECT;
-        String[] paths = null;
-        while (token != XContentParser.Token.END_OBJECT) {
-            if (token == XContentParser.Token.FIELD_NAME) {
-                currentFieldName = parser.currentName();
-                paths = splitAndValidatePath(currentFieldName);
-                if (containsDisabledObjectMapper(mapper, paths)) {
-                    parser.nextToken();
-                    parser.skipChildren();
+        try {
+            assert token == XContentParser.Token.FIELD_NAME || token == XContentParser.Token.END_OBJECT;
+            String[] paths = null;
+            context.incrementFieldCurrentDepth();
+            context.checkFieldDepthLimit();
+            while (token != XContentParser.Token.END_OBJECT) {
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    currentFieldName = parser.currentName();
+                    paths = splitAndValidatePath(currentFieldName);
+                    if (containsDisabledObjectMapper(mapper, paths)) {
+                        parser.nextToken();
+                        parser.skipChildren();
+                    }
+                } else if (token == XContentParser.Token.START_OBJECT) {
+                    parseObject(context, mapper, currentFieldName, paths);
+                } else if (token == XContentParser.Token.START_ARRAY) {
+                    parseArray(context, mapper, currentFieldName, paths);
+                } else if (token == XContentParser.Token.VALUE_NULL) {
+                    parseNullValue(context, mapper, currentFieldName, paths);
+                } else if (token == null) {
+                    throw new MapperParsingException(
+                        "object mapping for ["
+                            + mapper.name()
+                            + "] tried to parse field ["
+                            + currentFieldName
+                            + "] as object, but got EOF, has a concrete value been provided to it?"
+                    );
+                } else if (token.isValue()) {
+                    parseValue(context, mapper, currentFieldName, token, paths);
                 }
-            } else if (token == XContentParser.Token.START_OBJECT) {
-                parseObject(context, mapper, currentFieldName, paths);
-            } else if (token == XContentParser.Token.START_ARRAY) {
-                parseArray(context, mapper, currentFieldName, paths);
-            } else if (token == XContentParser.Token.VALUE_NULL) {
-                parseNullValue(context, mapper, currentFieldName, paths);
-            } else if (token == null) {
-                throw new MapperParsingException(
-                    "object mapping for ["
-                        + mapper.name()
-                        + "] tried to parse field ["
-                        + currentFieldName
-                        + "] as object, but got EOF, has a concrete value been provided to it?"
-                );
-            } else if (token.isValue()) {
-                parseValue(context, mapper, currentFieldName, token, paths);
+                token = parser.nextToken();
             }
-            token = parser.nextToken();
+        } finally {
+            context.decrementFieldCurrentDepth();
         }
     }
 
     private static void nested(ParseContext context, ObjectMapper.Nested nested) {
         ParseContext.Document nestedDoc = context.doc();
         ParseContext.Document parentDoc = nestedDoc.getParent();
+        Version indexVersion = context.indexSettings().getIndexVersionCreated();
         if (nested.isIncludeInParent()) {
-            addFields(nestedDoc, parentDoc);
+            addFields(indexVersion, nestedDoc, parentDoc);
         }
         if (nested.isIncludeInRoot()) {
             ParseContext.Document rootDoc = context.rootDoc();
-            // don't add it twice, if its included in parent, and we are handling the master doc...
+            // don't add it twice, if its included in parent, and we are handling the cluster-manager doc...
             if (!nested.isIncludeInParent() || parentDoc != rootDoc) {
-                addFields(nestedDoc, rootDoc);
+                addFields(indexVersion, nestedDoc, rootDoc);
             }
         }
     }
 
-    private static void addFields(ParseContext.Document nestedDoc, ParseContext.Document rootDoc) {
+    private static void addFields(Version indexVersion, ParseContext.Document nestedDoc, ParseContext.Document rootDoc) {
+        String nestedPathFieldName = NestedPathFieldMapper.name(indexVersion);
         for (IndexableField field : nestedDoc.getFields()) {
-            if (!field.name().equals(TypeFieldMapper.NAME)) {
+            if (field.name().equals(nestedPathFieldName) == false) {
                 rootDoc.add(field);
             }
         }
@@ -498,7 +511,7 @@ private static ParseContext nestedContext(ParseContext context, ObjectMapper map
         // the type of the nested doc starts with __, so we can identify that its a nested one in filters
         // note, we don't prefix it with the type of the doc since it allows us to execute a nested query
         // across types (for example, with similar nested objects)
-        nestedDoc.add(new Field(TypeFieldMapper.NAME, mapper.nestedTypePathAsString(), TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+        nestedDoc.add(NestedPathFieldMapper.field(context.indexSettings().getIndexVersionCreated(), mapper.nestedTypePath()));
         return context;
     }
 
@@ -557,50 +570,59 @@ private static void parseObject(final ParseContext context, ObjectMapper mapper,
 
     private static void parseArray(ParseContext context, ObjectMapper parentMapper, String lastFieldName, String[] paths)
         throws IOException {
-        String arrayFieldName = lastFieldName;
-
-        Mapper mapper = getMapper(context, parentMapper, lastFieldName, paths);
-        if (mapper != null) {
-            // There is a concrete mapper for this field already. Need to check if the mapper
-            // expects an array, if so we pass the context straight to the mapper and if not
-            // we serialize the array components
-            if (parsesArrayValue(mapper)) {
-                parseObjectOrField(context, mapper);
-            } else {
-                parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
-            }
-        } else {
-            arrayFieldName = paths[paths.length - 1];
-            lastFieldName = arrayFieldName;
-            Tuple<Integer, ObjectMapper> parentMapperTuple = getDynamicParentMapper(context, paths, parentMapper);
-            parentMapper = parentMapperTuple.v2();
-            ObjectMapper.Dynamic dynamic = dynamicOrDefault(parentMapper, context);
-            if (dynamic == ObjectMapper.Dynamic.STRICT) {
-                throw new StrictDynamicMappingException(parentMapper.fullPath(), arrayFieldName);
-            } else if (dynamic == ObjectMapper.Dynamic.TRUE) {
-                Mapper.Builder builder = context.root().findTemplateBuilder(context, arrayFieldName, XContentFieldType.OBJECT);
-                if (builder == null) {
-                    parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
+        try {
+            String arrayFieldName = lastFieldName;
+            context.incrementFieldArrayDepth();
+            context.checkFieldArrayDepthLimit();
+
+            Mapper mapper = getMapper(context, parentMapper, lastFieldName, paths);
+            if (mapper != null) {
+                // There is a concrete mapper for this field already. Need to check if the mapper
+                // expects an array, if so we pass the context straight to the mapper and if not
+                // we serialize the array components
+                if (parsesArrayValue(mapper)) {
+                    parseObjectOrField(context, mapper);
                 } else {
-                    Mapper.BuilderContext builderContext = new Mapper.BuilderContext(context.indexSettings().getSettings(), context.path());
-                    mapper = builder.build(builderContext);
-                    assert mapper != null;
-                    if (parsesArrayValue(mapper)) {
-                        context.addDynamicMapper(mapper);
-                        context.path().add(arrayFieldName);
-                        parseObjectOrField(context, mapper);
-                        context.path().remove();
-                    } else {
+                    parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
+                }
+            } else {
+                arrayFieldName = paths[paths.length - 1];
+                lastFieldName = arrayFieldName;
+                Tuple<Integer, ObjectMapper> parentMapperTuple = getDynamicParentMapper(context, paths, parentMapper);
+                parentMapper = parentMapperTuple.v2();
+                ObjectMapper.Dynamic dynamic = dynamicOrDefault(parentMapper, context);
+                if (dynamic == ObjectMapper.Dynamic.STRICT) {
+                    throw new StrictDynamicMappingException(parentMapper.fullPath(), arrayFieldName);
+                } else if (dynamic == ObjectMapper.Dynamic.TRUE) {
+                    Mapper.Builder builder = context.root().findTemplateBuilder(context, arrayFieldName, XContentFieldType.OBJECT);
+                    if (builder == null) {
                         parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
+                    } else {
+                        Mapper.BuilderContext builderContext = new Mapper.BuilderContext(
+                            context.indexSettings().getSettings(),
+                            context.path()
+                        );
+                        mapper = builder.build(builderContext);
+                        assert mapper != null;
+                        if (parsesArrayValue(mapper)) {
+                            context.addDynamicMapper(mapper);
+                            context.path().add(arrayFieldName);
+                            parseObjectOrField(context, mapper);
+                            context.path().remove();
+                        } else {
+                            parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
+                        }
                     }
+                } else {
+                    // TODO: shouldn't this skip, not parse?
+                    parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
+                }
+                for (int i = 0; i < parentMapperTuple.v1(); i++) {
+                    context.path().remove();
                 }
-            } else {
-                // TODO: shouldn't this skip, not parse?
-                parseNonDynamicArray(context, parentMapper, lastFieldName, arrayFieldName);
-            }
-            for (int i = 0; i < parentMapperTuple.v1(); i++) {
-                context.path().remove();
             }
+        } finally {
+            context.decrementFieldArrayDepth();
         }
     }
 
@@ -741,7 +763,7 @@ private static Mapper.Builder<?> createBuilderFromDynamicValue(
                             DateFieldMapper.Resolution.MILLISECONDS,
                             dateTimeFormatter,
                             ignoreMalformed,
-                            Version.indexCreated(context.indexSettings().getSettings())
+                            IndexMetadata.indexCreated(context.indexSettings().getSettings())
                         );
                     }
                     return builder;
diff --git a/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldMapper.java
index c1ff7fac39111..94bc4806ba0e0 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldMapper.java
@@ -49,8 +49,7 @@
  * sure to passes an empty multi-fields list to help prevent conflicting sub-keys from being
  * registered.
  *
- * Note: we anticipate that 'flattened' fields will be the only implementation of this
- * interface. Flattened object fields live in the 'mapper-flattened' module.
+ * @opensearch.internal
  */
 public abstract class DynamicKeyFieldMapper extends FieldMapper {
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldTypeLookup.java b/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldTypeLookup.java
index fed914d420eb9..13150ddc50a51 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldTypeLookup.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DynamicKeyFieldTypeLookup.java
@@ -44,6 +44,8 @@
  *
  * Note: we anticipate that 'flattened' fields will be the only implementation {@link DynamicKeyFieldMapper}.
  * Flattened object fields live in the 'mapper-flattened' module.
+ *
+ * @opensearch.internal
  */
 class DynamicKeyFieldTypeLookup {
     private final Map<String, DynamicKeyFieldMapper> mappers;
diff --git a/server/src/main/java/org/opensearch/index/mapper/DynamicTemplate.java b/server/src/main/java/org/opensearch/index/mapper/DynamicTemplate.java
index e3afb80344686..a20ad43bd70af 100644
--- a/server/src/main/java/org/opensearch/index/mapper/DynamicTemplate.java
+++ b/server/src/main/java/org/opensearch/index/mapper/DynamicTemplate.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -44,8 +44,18 @@
 import java.util.Map;
 import java.util.TreeMap;
 
+/**
+ * A template that is dynamic based on field types
+ *
+ * @opensearch.internal
+ */
 public class DynamicTemplate implements ToXContentObject {
 
+    /**
+     * Match type of the template
+     *
+     * @opensearch.internal
+     */
     public enum MatchType {
         SIMPLE {
             @Override
@@ -83,7 +93,11 @@ public static MatchType fromString(String value) {
         public abstract boolean matches(String regex, String value);
     }
 
-    /** The type of a field as detected while parsing a json document. */
+    /**
+     * The type of a field as detected while parsing a json document.
+     *
+     * @opensearch.internal
+     */
     public enum XContentFieldType {
         OBJECT {
             @Override
diff --git a/server/src/main/java/org/opensearch/index/mapper/FieldAliasMapper.java b/server/src/main/java/org/opensearch/index/mapper/FieldAliasMapper.java
index d716ec1e828f9..86c92ec19a2f7 100644
--- a/server/src/main/java/org/opensearch/index/mapper/FieldAliasMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/FieldAliasMapper.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -46,10 +46,17 @@
  *
  * A field alias has no concrete field mappings of its own, but instead points to another field by
  * its path. Once defined, an alias can be used in place of the concrete field name in search requests.
+ *
+ * @opensearch.internal
  */
 public final class FieldAliasMapper extends Mapper {
     public static final String CONTENT_TYPE = "alias";
 
+    /**
+     * Parameter names
+     *
+     * @opensearch.internal
+     */
     public static class Names {
         public static final String PATH = "path";
     }
@@ -136,6 +143,11 @@ public void validate(MappingLookup mappers) {
         }
     }
 
+    /**
+     * The type parser
+     *
+     * @opensearch.internal
+     */
     public static class TypeParser implements Mapper.TypeParser {
         @Override
         public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
@@ -149,6 +161,11 @@ public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext
         }
     }
 
+    /**
+     * The bulider for the field alias field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends Mapper.Builder<FieldAliasMapper.Builder> {
         private String name;
         private String path;
diff --git a/server/src/main/java/org/opensearch/index/mapper/FieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/FieldMapper.java
index 9c383d4b5a653..f8514c86fa418 100644
--- a/server/src/main/java/org/opensearch/index/mapper/FieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/FieldMapper.java
@@ -32,18 +32,15 @@
 
 package org.opensearch.index.mapper;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.index.IndexOptions;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.support.AbstractXContentParser;
+import org.opensearch.core.xcontent.AbstractXContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.mapper.FieldNamesFieldMapper.FieldNamesFieldType;
 
@@ -57,9 +54,15 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Spliterators;
 import java.util.TreeMap;
 import java.util.stream.StreamSupport;
 
+/**
+ * The base OpenSearch Field Mapper
+ *
+ * @opensearch.internal
+ */
 public abstract class FieldMapper extends Mapper implements Cloneable {
     public static final Setting<Boolean> IGNORE_MALFORMED_SETTING = Setting.boolSetting(
         "index.mapping.ignore_malformed",
@@ -68,6 +71,11 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
     );
     public static final Setting<Boolean> COERCE_SETTING = Setting.boolSetting("index.mapping.coerce", false, Property.IndexScope);
 
+    /**
+     * Base builder for all field mappers
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder<T extends Builder<T>> extends Mapper.Builder<T> {
 
         protected final FieldType fieldType;
@@ -258,6 +266,8 @@ public void parse(ParseContext context) throws IOException {
         try {
             parseCreateField(context);
         } catch (Exception e) {
+            boolean ignore_malformed = false;
+            if (context.indexSettings() != null) ignore_malformed = IGNORE_MALFORMED_SETTING.get(context.indexSettings().getSettings());
             String valuePreview = "";
             try {
                 XContentParser parser = context.parser();
@@ -268,23 +278,27 @@ public void parse(ParseContext context) throws IOException {
                     valuePreview = complexValue.toString();
                 }
             } catch (Exception innerException) {
+                if (ignore_malformed == false) {
+                    throw new MapperParsingException(
+                        "failed to parse field [{}] of type [{}] in document with id '{}'. " + "Could not parse field value preview,",
+                        e,
+                        fieldType().name(),
+                        fieldType().typeName(),
+                        context.sourceToParse().id()
+                    );
+                }
+            }
+
+            if (ignore_malformed == false) {
                 throw new MapperParsingException(
-                    "failed to parse field [{}] of type [{}] in document with id '{}'. " + "Could not parse field value preview,",
+                    "failed to parse field [{}] of type [{}] in document with id '{}'. " + "Preview of field's value: '{}'",
                     e,
                     fieldType().name(),
                     fieldType().typeName(),
-                    context.sourceToParse().id()
+                    context.sourceToParse().id(),
+                    valuePreview
                 );
             }
-
-            throw new MapperParsingException(
-                "failed to parse field [{}] of type [{}] in document with id '{}'. " + "Preview of field's value: '{}'",
-                e,
-                fieldType().name(),
-                fieldType().typeName(),
-                context.sourceToParse().id(),
-                valuePreview
-            );
         }
         multiFields.parse(this, context);
     }
@@ -555,15 +569,25 @@ protected static String indexOptionToString(IndexOptions indexOption) {
 
     protected abstract String contentType();
 
+    /**
+     * Multi field implementation used across field mappers
+     *
+     * @opensearch.internal
+     */
     public static class MultiFields implements Iterable<Mapper> {
 
         public static MultiFields empty() {
-            return new MultiFields(ImmutableOpenMap.<String, FieldMapper>of());
+            return new MultiFields(Map.of());
         }
 
+        /**
+         * Concrete builder for field mappers
+         *
+         * @opensearch.internal
+         */
         public static class Builder {
 
-            private final ImmutableOpenMap.Builder<String, Mapper.Builder> mapperBuilders = ImmutableOpenMap.builder();
+            private final Map<String, Mapper.Builder> mapperBuilders = new HashMap<>();
 
             public Builder add(Mapper.Builder builder) {
                 mapperBuilders.put(builder.name(), builder);
@@ -597,30 +621,25 @@ public MultiFields build(Mapper.Builder mainFieldBuilder, BuilderContext context
                     return empty();
                 } else {
                     context.path().add(mainFieldBuilder.name());
-                    ImmutableOpenMap.Builder mapperBuilders = this.mapperBuilders;
-                    for (ObjectObjectCursor<String, Mapper.Builder> cursor : this.mapperBuilders) {
-                        String key = cursor.key;
-                        Mapper.Builder value = cursor.value;
+                    Map mapperBuilders = this.mapperBuilders;
+                    for (final Map.Entry<String, Mapper.Builder> cursor : this.mapperBuilders.entrySet()) {
+                        String key = cursor.getKey();
+                        Mapper.Builder value = cursor.getValue();
                         Mapper mapper = value.build(context);
                         assert mapper instanceof FieldMapper;
                         mapperBuilders.put(key, mapper);
                     }
                     context.path().remove();
-                    ImmutableOpenMap.Builder<String, FieldMapper> mappers = mapperBuilders.cast();
-                    return new MultiFields(mappers.build());
+                    final Map<String, FieldMapper> mappers = (Map<String, FieldMapper>) mapperBuilders;
+                    return new MultiFields(mappers);
                 }
             }
         }
 
-        private final ImmutableOpenMap<String, FieldMapper> mappers;
+        private final Map<String, FieldMapper> mappers;
 
-        private MultiFields(ImmutableOpenMap<String, FieldMapper> mappers) {
-            ImmutableOpenMap.Builder<String, FieldMapper> builder = new ImmutableOpenMap.Builder<>();
-            // we disable the all in multi-field mappers
-            for (ObjectObjectCursor<String, FieldMapper> cursor : mappers) {
-                builder.put(cursor.key, cursor.value);
-            }
-            this.mappers = builder.build();
+        private MultiFields(final Map<String, FieldMapper> mappers) {
+            this.mappers = Collections.unmodifiableMap(mappers);
         }
 
         public void parse(FieldMapper mainField, ParseContext context) throws IOException {
@@ -631,19 +650,17 @@ public void parse(FieldMapper mainField, ParseContext context) throws IOExceptio
             }
 
             context = context.createMultiFieldContext();
-
             context.path().add(mainField.simpleName());
-            for (ObjectCursor<FieldMapper> cursor : mappers.values()) {
-                cursor.value.parse(context);
+            for (final FieldMapper cursor : mappers.values()) {
+                cursor.parse(context);
             }
             context.path().remove();
         }
 
         public MultiFields merge(MultiFields mergeWith) {
-            ImmutableOpenMap.Builder<String, FieldMapper> newMappersBuilder = ImmutableOpenMap.builder(mappers);
+            final Map<String, FieldMapper> newMappersBuilder = new HashMap<>(mappers);
 
-            for (ObjectCursor<FieldMapper> cursor : mergeWith.mappers.values()) {
-                FieldMapper mergeWithMapper = cursor.value;
+            for (final FieldMapper mergeWithMapper : mergeWith.mappers.values()) {
                 FieldMapper mergeIntoMapper = mappers.get(mergeWithMapper.simpleName());
                 if (mergeIntoMapper == null) {
                     newMappersBuilder.put(mergeWithMapper.simpleName(), mergeWithMapper);
@@ -653,19 +670,19 @@ public MultiFields merge(MultiFields mergeWith) {
                 }
             }
 
-            ImmutableOpenMap<String, FieldMapper> mappers = newMappersBuilder.build();
+            final Map<String, FieldMapper> mappers = Collections.unmodifiableMap(newMappersBuilder);
             return new MultiFields(mappers);
         }
 
         @Override
         public Iterator<Mapper> iterator() {
-            return StreamSupport.stream(mappers.values().spliterator(), false).map((p) -> (Mapper) p.value).iterator();
+            return StreamSupport.stream(Spliterators.spliterator(mappers.values(), 0), false).map((p) -> (Mapper) p).iterator();
         }
 
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             if (!mappers.isEmpty()) {
                 // sort the mappers so we get consistent serialization format
-                Mapper[] sortedMappers = mappers.values().toArray(Mapper.class);
+                Mapper[] sortedMappers = mappers.values().toArray(new FieldMapper[0]);
                 Arrays.sort(sortedMappers, new Comparator<Mapper>() {
                     @Override
                     public int compare(Mapper o1, Mapper o2) {
@@ -684,6 +701,8 @@ public int compare(Mapper o1, Mapper o2) {
 
     /**
      * Represents a list of fields with optional boost factor where the current field should be copied to
+     *
+     * @opensearch.internal
      */
     public static class CopyTo {
 
@@ -710,6 +729,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             return builder;
         }
 
+        /**
+         * Builder for the copyTo field
+         *
+         * @opensearch.internal
+         */
         public static class Builder {
             private final List<String> copyToBuilders = new ArrayList<>();
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/FieldNamesFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/FieldNamesFieldMapper.java
index 500df197f4f04..dc2ea1f35f8b8 100644
--- a/server/src/main/java/org/opensearch/index/mapper/FieldNamesFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/FieldNamesFieldMapper.java
@@ -48,6 +48,8 @@
 /**
  * A mapper that indexes the field names of a document under <code>_field_names</code>. This mapper is typically useful in order
  * to have fast <code>exists</code> and <code>missing</code> queries/filters.
+ *
+ * @opensearch.internal
  */
 public class FieldNamesFieldMapper extends MetadataFieldMapper {
 
@@ -62,6 +64,11 @@ public ParametrizedFieldMapper.Builder getMergeBuilder() {
         return new Builder(indexVersionCreated).init(this);
     }
 
+    /**
+     * Parameter defaults
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final String NAME = FieldNamesFieldMapper.NAME;
 
@@ -85,6 +92,11 @@ private static FieldNamesFieldMapper toType(FieldMapper in) {
         "Disabling _field_names is not necessary because it no longer carries a large index overhead. Support for the `enabled` "
             + "setting will be removed in a future major version. Please remove it from your mappings and templates.";
 
+    /**
+     * Builder for the FieldNames field mapper
+     *
+     * @opensearch.internal
+     */
     static class Builder extends MetadataFieldMapper.Builder {
 
         private final Parameter<Explicit<Boolean>> enabled = updateableBoolParam(
@@ -120,6 +132,11 @@ public FieldNamesFieldMapper build(BuilderContext context) {
         c -> new Builder(c.indexVersionCreated())
     );
 
+    /**
+     * Field type for FieldNames field mapper
+     *
+     * @opensearch.internal
+     */
     public static final class FieldNamesFieldType extends TermBasedFieldType {
 
         private final boolean enabled;
diff --git a/server/src/main/java/org/opensearch/index/mapper/FieldTypeLookup.java b/server/src/main/java/org/opensearch/index/mapper/FieldTypeLookup.java
index fd1f2df1131ab..8e1b6f2a3c08b 100644
--- a/server/src/main/java/org/opensearch/index/mapper/FieldTypeLookup.java
+++ b/server/src/main/java/org/opensearch/index/mapper/FieldTypeLookup.java
@@ -45,6 +45,8 @@
 
 /**
  * An immutable container for looking up {@link MappedFieldType}s by their name.
+ *
+ * @opensearch.internal
  */
 class FieldTypeLookup implements Iterable<MappedFieldType> {
 
@@ -151,9 +153,7 @@ public Set<String> sourcePaths(String field) {
             }
         }
 
-        return fieldToCopiedFields.containsKey(resolvedField)
-            ? fieldToCopiedFields.get(resolvedField)
-            : org.opensearch.common.collect.Set.of(resolvedField);
+        return fieldToCopiedFields.containsKey(resolvedField) ? fieldToCopiedFields.get(resolvedField) : Set.of(resolvedField);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/mapper/FlatObjectFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/FlatObjectFieldMapper.java
new file mode 100644
index 0000000000000..db35c3edcc4a8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/mapper/FlatObjectFieldMapper.java
@@ -0,0 +1,788 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.FieldType;
+import org.apache.lucene.document.SortedSetDocValuesField;
+import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.BoostQuery;
+import org.apache.lucene.search.MultiTermQuery;
+import org.apache.lucene.search.PrefixQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermInSetQuery;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.search.TermRangeQuery;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.collect.Iterators;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.lucene.search.AutomatonQueries;
+import org.opensearch.common.xcontent.JsonToStringXContentParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.analysis.NamedAnalyzer;
+import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.query.QueryShardException;
+import org.opensearch.search.aggregations.support.CoreValuesSourceType;
+import org.opensearch.search.lookup.SearchLookup;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiFunction;
+import java.util.function.Supplier;
+
+import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
+
+/**
+ * A field mapper for flat_objects.
+ * This mapper accepts JSON object and treat as string fields in one index.
+ * @opensearch.internal
+ */
+public final class FlatObjectFieldMapper extends DynamicKeyFieldMapper {
+
+    public static final String CONTENT_TYPE = "flat_object";
+    private static final String VALUE_AND_PATH_SUFFIX = "._valueAndPath";
+    private static final String VALUE_SUFFIX = "._value";
+    private static final String DOT_SYMBOL = ".";
+    private static final String EQUAL_SYMBOL = "=";
+
+    /**
+     * In flat_object field mapper, field type is similar to keyword field type
+     * Cannot be tokenized, can OmitNorms, and can setIndexOption.
+     * @opensearch.internal
+     */
+    public static class Defaults {
+        public static final FieldType FIELD_TYPE = new FieldType();
+
+        static {
+            FIELD_TYPE.setTokenized(false);
+            FIELD_TYPE.setOmitNorms(true);
+            FIELD_TYPE.setIndexOptions(IndexOptions.DOCS);
+            FIELD_TYPE.freeze();
+        }
+
+    }
+
+    @Override
+    public MappedFieldType keyedFieldType(String key) {
+        return new FlatObjectFieldType(this.name() + DOT_SYMBOL + key, this.name());
+    }
+
+    /**
+     * FlatObjectFieldType is the parent field type.
+     */
+    public static class FlatObjectField extends Field {
+
+        public FlatObjectField(String field, BytesRef term, FieldType ft) {
+            super(field, term, ft);
+        }
+
+    }
+
+    /**
+     * The builder for the flat_object field mapper using default parameters
+     * @opensearch.internal
+     */
+    public static class Builder extends FieldMapper.Builder<Builder> {
+
+        public Builder(String name) {
+            super(name, Defaults.FIELD_TYPE);
+            builder = this;
+        }
+
+        private FlatObjectFieldType buildFlatObjectFieldType(BuilderContext context, FieldType fieldType) {
+            return new FlatObjectFieldType(buildFullName(context), fieldType);
+        }
+
+        /**
+         * ValueFieldMapper is the subfield type for values in the Json.
+         * use a {@link KeywordFieldMapper.KeywordField}
+         */
+        private ValueFieldMapper buildValueFieldMapper(BuilderContext context, FieldType fieldType, FlatObjectFieldType fft) {
+            String fullName = buildFullName(context);
+            FieldType vft = new FieldType(fieldType);
+            KeywordFieldMapper.KeywordFieldType valueFieldType = new KeywordFieldMapper.KeywordFieldType(fullName + VALUE_SUFFIX, vft);
+
+            fft.setValueFieldType(valueFieldType);
+            return new ValueFieldMapper(vft, valueFieldType);
+        }
+
+        /**
+         * ValueAndPathFieldMapper is the subfield type for path=value format in the Json.
+         * also use a {@link KeywordFieldMapper.KeywordField}
+         */
+        private ValueAndPathFieldMapper buildValueAndPathFieldMapper(BuilderContext context, FieldType fieldType, FlatObjectFieldType fft) {
+            String fullName = buildFullName(context);
+            FieldType vft = new FieldType(fieldType);
+            KeywordFieldMapper.KeywordFieldType ValueAndPathFieldType = new KeywordFieldMapper.KeywordFieldType(
+                fullName + VALUE_AND_PATH_SUFFIX,
+                vft
+            );
+            fft.setValueAndPathFieldType(ValueAndPathFieldType);
+            return new ValueAndPathFieldMapper(vft, ValueAndPathFieldType);
+        }
+
+        @Override
+        public FlatObjectFieldMapper build(BuilderContext context) {
+            FieldType fieldtype = new FieldType(Defaults.FIELD_TYPE);
+            FlatObjectFieldType fft = buildFlatObjectFieldType(context, fieldtype);
+            return new FlatObjectFieldMapper(
+                name,
+                Defaults.FIELD_TYPE,
+                fft,
+                buildValueFieldMapper(context, fieldtype, fft),
+                buildValueAndPathFieldMapper(context, fieldtype, fft),
+                CopyTo.empty(),
+                this
+            );
+        }
+    }
+
+    public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n));
+
+    /**
+     * Creates a new TypeParser for flatObjectFieldMapper that does not use ParameterizedFieldMapper
+     */
+    public static class TypeParser implements Mapper.TypeParser {
+        private final BiFunction<String, ParserContext, Builder> builderFunction;
+
+        public TypeParser(BiFunction<String, ParserContext, Builder> builderFunction) {
+            this.builderFunction = builderFunction;
+        }
+
+        @Override
+        public Mapper.Builder<?> parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
+            Builder builder = builderFunction.apply(name, parserContext);
+            return builder;
+        }
+    }
+
+    /**
+     * flat_object fields type contains its own fieldType, one valueFieldType and one valueAndPathFieldType
+     * @opensearch.internal
+     */
+    public static final class FlatObjectFieldType extends StringFieldType {
+
+        private final int ignoreAbove;
+        private final String nullValue;
+
+        private final String mappedFieldTypeName;
+
+        private KeywordFieldMapper.KeywordFieldType valueFieldType;
+
+        private KeywordFieldMapper.KeywordFieldType valueAndPathFieldType;
+
+        public FlatObjectFieldType(String name, boolean isSearchable, boolean hasDocValues, Map<String, String> meta) {
+            super(name, isSearchable, false, true, TextSearchInfo.SIMPLE_MATCH_ONLY, meta);
+            setIndexAnalyzer(Lucene.KEYWORD_ANALYZER);
+            this.ignoreAbove = Integer.MAX_VALUE;
+            this.nullValue = null;
+            this.mappedFieldTypeName = null;
+        }
+
+        public FlatObjectFieldType(String name, FieldType fieldType) {
+            super(
+                name,
+                fieldType.indexOptions() != IndexOptions.NONE,
+                false,
+                true,
+                new TextSearchInfo(fieldType, null, Lucene.KEYWORD_ANALYZER, Lucene.KEYWORD_ANALYZER),
+                Collections.emptyMap()
+            );
+            this.ignoreAbove = Integer.MAX_VALUE;
+            this.nullValue = null;
+            this.mappedFieldTypeName = null;
+        }
+
+        public FlatObjectFieldType(String name, NamedAnalyzer analyzer) {
+            super(name, true, false, true, new TextSearchInfo(Defaults.FIELD_TYPE, null, analyzer, analyzer), Collections.emptyMap());
+            this.ignoreAbove = Integer.MAX_VALUE;
+            this.nullValue = null;
+            this.mappedFieldTypeName = null;
+        }
+
+        public FlatObjectFieldType(String name, String mappedFieldTypeName) {
+            super(
+                name,
+                true,
+                false,
+                true,
+                new TextSearchInfo(Defaults.FIELD_TYPE, null, Lucene.KEYWORD_ANALYZER, Lucene.KEYWORD_ANALYZER),
+                Collections.emptyMap()
+            );
+            this.ignoreAbove = Integer.MAX_VALUE;
+            this.nullValue = null;
+            this.mappedFieldTypeName = mappedFieldTypeName;
+        }
+
+        void setValueFieldType(KeywordFieldMapper.KeywordFieldType valueFieldType) {
+            this.valueFieldType = valueFieldType;
+        }
+
+        void setValueAndPathFieldType(KeywordFieldMapper.KeywordFieldType ValueAndPathFieldType) {
+            this.valueAndPathFieldType = ValueAndPathFieldType;
+        }
+
+        public KeywordFieldMapper.KeywordFieldType getValueFieldType() {
+            return this.valueFieldType;
+        }
+
+        public KeywordFieldMapper.KeywordFieldType getValueAndPathFieldType() {
+            return this.valueAndPathFieldType;
+        }
+
+        @Override
+        public String typeName() {
+            return CONTENT_TYPE;
+        }
+
+        NamedAnalyzer normalizer() {
+            return indexAnalyzer();
+        }
+
+        /**
+         *
+         * Fielddata is an in-memory data structure that is used for aggregations, sorting, and scripting.
+         * @param fullyQualifiedIndexName the name of the index this field-data is build for
+         * @param searchLookup a {@link SearchLookup} supplier to allow for accessing other fields values in the context of runtime fields
+         * @return IndexFieldData.Builder
+         */
+        @Override
+        public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
+            failIfNoDocValues();
+            return new SortedSetOrdinalsIndexFieldData.Builder(name(), CoreValuesSourceType.BYTES);
+        }
+
+        @Override
+        public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchLookup, String format) {
+            if (format != null) {
+                throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+            }
+
+            return new SourceValueFetcher(name(), context, nullValue) {
+                @Override
+                protected String parseSourceValue(Object value) {
+                    String flatObjectKeywordValue = value.toString();
+
+                    if (flatObjectKeywordValue.length() > ignoreAbove) {
+                        return null;
+                    }
+
+                    NamedAnalyzer normalizer = normalizer();
+                    if (normalizer == null) {
+                        return flatObjectKeywordValue;
+                    }
+
+                    try {
+                        return normalizeValue(normalizer, name(), flatObjectKeywordValue);
+                    } catch (IOException e) {
+                        throw new UncheckedIOException(e);
+                    }
+                }
+            };
+        }
+
+        @Override
+        public Object valueForDisplay(Object value) {
+            if (value == null) {
+                return null;
+            }
+            // flat_objects are internally stored as utf8 bytes
+            BytesRef binaryValue = (BytesRef) value;
+            return binaryValue.utf8ToString();
+        }
+
+        @Override
+        protected BytesRef indexedValueForSearch(Object value) {
+            if (getTextSearchInfo().getSearchAnalyzer() == Lucene.KEYWORD_ANALYZER) {
+                // flat_object analyzer with the default attribute source which encodes terms using UTF8
+                // in that case we skip normalization, which may be slow if there many terms need to
+                // parse (eg. large terms query) since Analyzer.normalize involves things like creating
+                // attributes through reflection
+                // This if statement will be used whenever a normalizer is NOT configured
+                return super.indexedValueForSearch(value);
+            }
+
+            if (value == null) {
+                return null;
+            }
+            value = inputToString(value);
+            return getTextSearchInfo().getSearchAnalyzer().normalize(name(), value.toString());
+        }
+
+        /**
+         * redirect queries with rewrite value to rewriteSearchValue and directSubFieldName
+         */
+        @Override
+        public Query termQuery(Object value, @Nullable QueryShardContext context) {
+
+            String searchValueString = inputToString(value);
+            String directSubFieldName = directSubfield();
+            String rewriteSearchValue = rewriteValue(searchValueString);
+
+            failIfNotIndexed();
+            Query query;
+            query = new TermQuery(new Term(directSubFieldName, indexedValueForSearch(rewriteSearchValue)));
+            if (boost() != 1f) {
+                query = new BoostQuery(query, boost());
+            }
+            return query;
+        }
+
+        @Override
+        public Query termsQuery(List<?> values, QueryShardContext context) {
+            failIfNotIndexed();
+            String directedSearchFieldName = directSubfield();
+            BytesRef[] bytesRefs = new BytesRef[values.size()];
+            for (int i = 0; i < bytesRefs.length; i++) {
+                String rewriteValues = rewriteValue(inputToString(values.get(i)));
+
+                bytesRefs[i] = indexedValueForSearch(new BytesRef(rewriteValues));
+
+            }
+
+            return new TermInSetQuery(directedSearchFieldName, bytesRefs);
+        }
+
+        /**
+         * To direct search fields, if a dot path was used in search query,
+         * then direct to flatObjectFieldName._valueAndPath subfield,
+         * else, direct to flatObjectFieldName._value subfield.
+         * @return directedSubFieldName
+         */
+        public String directSubfield() {
+            if (mappedFieldTypeName == null) {
+                return new StringBuilder().append(this.name()).append(VALUE_SUFFIX).toString();
+            } else {
+                return new StringBuilder().append(this.mappedFieldTypeName).append(VALUE_AND_PATH_SUFFIX).toString();
+            }
+        }
+
+        /**
+         * If the search key has mappedFieldTypeName as prefix,
+         * then the dot path was used in search query,
+         * then rewrite the searchValueString as the format "dotpath=value",
+         * @return rewriteSearchValue
+         */
+        public String rewriteValue(String searchValueString) {
+            if (!hasMappedFieldTyeNameInQueryFieldName(name())) {
+                return searchValueString;
+            } else {
+                String rewriteSearchValue = new StringBuilder().append(name()).append(EQUAL_SYMBOL).append(searchValueString).toString();
+                return rewriteSearchValue;
+            }
+
+        }
+
+        private boolean hasMappedFieldTyeNameInQueryFieldName(String input) {
+            String prefix = this.mappedFieldTypeName;
+            if (prefix == null) {
+                return false;
+            }
+            if (!input.startsWith(prefix)) {
+                return false;
+            }
+            String rest = input.substring(prefix.length());
+
+            if (rest.isEmpty()) {
+                return false;
+            } else {
+                return true;
+            }
+        }
+
+        private String inputToString(Object inputValue) {
+            if (inputValue instanceof Integer) {
+                String inputToString = Integer.toString((Integer) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof Float) {
+                String inputToString = Float.toString((Float) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof Boolean) {
+                String inputToString = Boolean.toString((Boolean) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof Short) {
+                String inputToString = Short.toString((Short) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof Long) {
+                String inputToString = Long.toString((Long) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof Double) {
+                String inputToString = Double.toString((Double) inputValue);
+                return inputToString;
+            } else if (inputValue instanceof BytesRef) {
+                String inputToString = (((BytesRef) inputValue).utf8ToString());
+                return inputToString;
+            } else if (inputValue instanceof String) {
+                String inputToString = (String) inputValue;
+                return inputToString;
+            } else if (inputValue instanceof Version) {
+                String inputToString = inputValue.toString();
+                return inputToString;
+            } else {
+                // default to cast toString
+                return inputValue.toString();
+            }
+        }
+
+        @Override
+        public Query prefixQuery(String value, MultiTermQuery.RewriteMethod method, boolean caseInsensitive, QueryShardContext context) {
+            String directSubfield = directSubfield();
+            String rewriteValue = rewriteValue(value);
+
+            if (context.allowExpensiveQueries() == false) {
+                throw new OpenSearchException(
+                    "[prefix] queries cannot be executed when '"
+                        + ALLOW_EXPENSIVE_QUERIES.getKey()
+                        + "' is set to false. For optimised prefix queries on text "
+                        + "fields please enable [index_prefixes]."
+                );
+            }
+            failIfNotIndexed();
+            if (method == null) {
+                method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
+            }
+            if (caseInsensitive) {
+                return AutomatonQueries.caseInsensitivePrefixQuery((new Term(directSubfield, indexedValueForSearch(rewriteValue))), method);
+            }
+            return new PrefixQuery(new Term(directSubfield, indexedValueForSearch(rewriteValue)), method);
+        }
+
+        @Override
+        public Query rangeQuery(Object lowerTerm, Object upperTerm, boolean includeLower, boolean includeUpper, QueryShardContext context) {
+            String directSubfield = directSubfield();
+            String rewriteUpperTerm = rewriteValue(inputToString(upperTerm));
+            String rewriteLowerTerm = rewriteValue(inputToString(lowerTerm));
+            if (context.allowExpensiveQueries() == false) {
+                throw new OpenSearchException(
+                    "[range] queries on [text] or [keyword] fields cannot be executed when '"
+                        + ALLOW_EXPENSIVE_QUERIES.getKey()
+                        + "' is set to false."
+                );
+            }
+            failIfNotIndexed();
+            return new TermRangeQuery(
+                directSubfield,
+                lowerTerm == null ? null : indexedValueForSearch(rewriteLowerTerm),
+                upperTerm == null ? null : indexedValueForSearch(rewriteUpperTerm),
+                includeLower,
+                includeUpper
+            );
+        }
+
+        /**
+         * if there is dot path. query the field name in flatObject parent field (mappedFieldTypeName).
+         * else query in _field_names system field
+         */
+        @Override
+        public Query existsQuery(QueryShardContext context) {
+            String searchKey;
+            String searchField;
+            if (hasMappedFieldTyeNameInQueryFieldName(name())) {
+                searchKey = this.mappedFieldTypeName;
+                searchField = name();
+            } else {
+                searchKey = FieldNamesFieldMapper.NAME;
+                searchField = name();
+            }
+            return new TermQuery(new Term(searchKey, indexedValueForSearch(searchField)));
+        }
+
+        @Override
+        public Query wildcardQuery(
+            String value,
+            @Nullable MultiTermQuery.RewriteMethod method,
+            boolean caseInsensitve,
+            QueryShardContext context
+        ) {
+            // flat_object field types are always normalized, so ignore case sensitivity and force normalize the wildcard
+            // query text
+            throw new QueryShardException(
+                context,
+                "Can only use wildcard queries on keyword and text fields - not on [" + name() + "] which is of type [" + typeName() + "]"
+            );
+
+        }
+
+    }
+
+    private final ValueFieldMapper valueFieldMapper;
+    private final ValueAndPathFieldMapper valueAndPathFieldMapper;
+
+    FlatObjectFieldMapper(
+        String simpleName,
+        FieldType fieldType,
+        FlatObjectFieldType mappedFieldType,
+        ValueFieldMapper valueFieldMapper,
+        ValueAndPathFieldMapper valueAndPathFieldMapper,
+        CopyTo copyTo,
+        Builder builder
+    ) {
+        super(simpleName, fieldType, mappedFieldType, copyTo);
+        assert fieldType.indexOptions().compareTo(IndexOptions.DOCS_AND_FREQS) <= 0;
+        this.fieldType = fieldType;
+        this.valueFieldMapper = valueFieldMapper;
+        this.valueAndPathFieldMapper = valueAndPathFieldMapper;
+        this.mappedFieldType = mappedFieldType;
+    }
+
+    @Override
+    protected FlatObjectFieldMapper clone() {
+        return (FlatObjectFieldMapper) super.clone();
+    }
+
+    @Override
+    protected void mergeOptions(FieldMapper other, List<String> conflicts) {
+
+    }
+
+    @Override
+    public FlatObjectFieldType fieldType() {
+        return (FlatObjectFieldType) super.fieldType();
+    }
+
+    @Override
+    protected void parseCreateField(ParseContext context) throws IOException {
+        String fieldName = null;
+
+        if (context.externalValueSet()) {
+            String value = context.externalValue().toString();
+            parseValueAddFields(context, value, fieldType().name());
+        } else {
+            JsonToStringXContentParser JsonToStringParser = new JsonToStringXContentParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.IGNORE_DEPRECATIONS,
+                context,
+                fieldType().name()
+            );
+            /**
+             * JsonToStringParser is the main parser class to transform JSON into stringFields in a XContentParser
+             * It reads the JSON object and parsed to a list of string
+             */
+            XContentParser parser = JsonToStringParser.parseObject();
+
+            XContentParser.Token currentToken;
+            while ((currentToken = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                switch (currentToken) {
+                    case FIELD_NAME:
+                        fieldName = parser.currentName();
+                        break;
+                    case VALUE_STRING:
+                        String value = parser.textOrNull();
+                        parseValueAddFields(context, value, fieldName);
+                        break;
+                }
+
+            }
+
+        }
+
+    }
+
+    @Override
+    public Iterator<Mapper> iterator() {
+        List<Mapper> subIterators = new ArrayList<>();
+        if (valueFieldMapper != null) {
+            subIterators.add(valueFieldMapper);
+        }
+        if (valueAndPathFieldMapper != null) {
+            subIterators.add(valueAndPathFieldMapper);
+        }
+        if (subIterators.size() == 0) {
+            return super.iterator();
+        }
+        @SuppressWarnings("unchecked")
+        Iterator<Mapper> concat = Iterators.concat(super.iterator(), subIterators.iterator());
+        return concat;
+    }
+
+    /**
+     * parseValueAddFields method will store data to Lucene.
+     * the JsonToStringXContentParser returns XContentParser with 3 string fields
+     * fieldName, fieldName._value, fieldName._valueAndPath.
+     * parseValueAddFields recognized string by the stringfield name,
+     * fieldName will be store through the parent FlatObjectFieldMapper,which contains all the keys
+     * fieldName._value will be store through the valueFieldMapper, which contains the values of the Json Object
+     * fieldName._valueAndPath will be store through the valueAndPathFieldMapper, which contains the "path=values" format
+     */
+    private void parseValueAddFields(ParseContext context, String value, String fieldName) throws IOException {
+
+        NamedAnalyzer normalizer = fieldType().normalizer();
+        if (normalizer != null) {
+            value = normalizeValue(normalizer, name(), value);
+        }
+
+        String[] valueTypeList = fieldName.split("\\._");
+        String valueType = "._" + valueTypeList[valueTypeList.length - 1];
+
+        if (fieldType.indexOptions() != IndexOptions.NONE || fieldType.stored()) {
+            // convert to utf8 only once before feeding postings/dv/stored fields
+
+            final BytesRef binaryValue = new BytesRef(fieldType().name() + DOT_SYMBOL + value);
+            Field field = new FlatObjectField(fieldType().name(), binaryValue, fieldType);
+
+            if (fieldType().hasDocValues() == false && fieldType.omitNorms()) {
+                createFieldNamesField(context);
+            }
+            if (fieldName.equals(fieldType().name())) {
+                context.doc().add(field);
+            }
+            if (valueType.equals(VALUE_SUFFIX)) {
+                if (valueFieldMapper != null) {
+                    valueFieldMapper.addField(context, value);
+                }
+            }
+            if (valueType.equals(VALUE_AND_PATH_SUFFIX)) {
+                if (valueAndPathFieldMapper != null) {
+                    valueAndPathFieldMapper.addField(context, value);
+                }
+            }
+
+            if (fieldType().hasDocValues()) {
+                if (fieldName.equals(fieldType().name())) {
+                    context.doc().add(new SortedSetDocValuesField(fieldType().name(), binaryValue));
+                }
+                if (valueType.equals(VALUE_SUFFIX)) {
+                    if (valueFieldMapper != null) {
+                        context.doc().add(new SortedSetDocValuesField(fieldType().name() + VALUE_SUFFIX, binaryValue));
+                    }
+                }
+                if (valueType.equals(VALUE_AND_PATH_SUFFIX)) {
+                    if (valueAndPathFieldMapper != null) {
+                        context.doc().add(new SortedSetDocValuesField(fieldType().name() + VALUE_AND_PATH_SUFFIX, binaryValue));
+                    }
+                }
+            }
+
+        }
+
+    }
+
+    private static String normalizeValue(NamedAnalyzer normalizer, String field, String value) throws IOException {
+        String normalizerErrorMessage = "The normalization token stream is "
+            + "expected to produce exactly 1 token, but got 0 for analyzer "
+            + normalizer
+            + " and input \""
+            + value
+            + "\"";
+        try (TokenStream ts = normalizer.tokenStream(field, value)) {
+            final CharTermAttribute termAtt = ts.addAttribute(CharTermAttribute.class);
+            ts.reset();
+            if (ts.incrementToken() == false) {
+                throw new IllegalStateException(normalizerErrorMessage);
+            }
+            final String newValue = termAtt.toString();
+            if (ts.incrementToken()) {
+                throw new IllegalStateException(normalizerErrorMessage);
+            }
+            ts.end();
+            return newValue;
+        }
+    }
+
+    @Override
+    protected String contentType() {
+        return CONTENT_TYPE;
+    }
+
+    private static final class ValueAndPathFieldMapper extends FieldMapper {
+
+        protected ValueAndPathFieldMapper(FieldType fieldType, KeywordFieldMapper.KeywordFieldType mappedFieldType) {
+            super(mappedFieldType.name(), fieldType, mappedFieldType, MultiFields.empty(), CopyTo.empty());
+        }
+
+        void addField(ParseContext context, String value) {
+            final BytesRef binaryValue = new BytesRef(value);
+            if (fieldType.indexOptions() != IndexOptions.NONE || fieldType.stored()) {
+                Field field = new KeywordFieldMapper.KeywordField(fieldType().name(), binaryValue, fieldType);
+
+                context.doc().add(field);
+
+                if (fieldType().hasDocValues() == false && fieldType.omitNorms()) {
+                    createFieldNamesField(context);
+                }
+            }
+        }
+
+        @Override
+        protected void parseCreateField(ParseContext context) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        protected void mergeOptions(FieldMapper other, List<String> conflicts) {
+
+        }
+
+        @Override
+        protected String contentType() {
+            return "valueAndPath";
+        }
+
+        @Override
+        public String toString() {
+            return fieldType().toString();
+        }
+
+    }
+
+    private static final class ValueFieldMapper extends FieldMapper {
+
+        protected ValueFieldMapper(FieldType fieldType, KeywordFieldMapper.KeywordFieldType mappedFieldType) {
+            super(mappedFieldType.name(), fieldType, mappedFieldType, MultiFields.empty(), CopyTo.empty());
+        }
+
+        void addField(ParseContext context, String value) {
+            final BytesRef binaryValue = new BytesRef(value);
+            if (fieldType.indexOptions() != IndexOptions.NONE || fieldType.stored()) {
+                Field field = new KeywordFieldMapper.KeywordField(fieldType().name(), binaryValue, fieldType);
+                context.doc().add(field);
+
+                if (fieldType().hasDocValues() == false && fieldType.omitNorms()) {
+                    createFieldNamesField(context);
+                }
+            }
+        }
+
+        @Override
+        protected void parseCreateField(ParseContext context) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        protected void mergeOptions(FieldMapper other, List<String> conflicts) {
+
+        }
+
+        @Override
+        protected String contentType() {
+            return "value";
+        }
+
+        @Override
+        public String toString() {
+            return fieldType().toString();
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/mapper/GeoPointFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/GeoPointFieldMapper.java
index 123af3a1fe761..e3dab3f892949 100644
--- a/server/src/main/java/org/opensearch/index/mapper/GeoPointFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/GeoPointFieldMapper.java
@@ -65,6 +65,8 @@
  * Field Mapper for geo_point types.
  *
  * Uses lucene 6 LatLonPoint encoding
+ *
+ * @opensearch.internal
  */
 public class GeoPointFieldMapper extends AbstractPointGeometryFieldMapper<List<ParsedGeoPoint>, List<? extends GeoPoint>> {
     public static final String CONTENT_TYPE = "geo_point";
@@ -76,6 +78,11 @@ public class GeoPointFieldMapper extends AbstractPointGeometryFieldMapper<List<P
         FIELD_TYPE.freeze();
     }
 
+    /**
+     * Concrete builder for geo_point types
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends AbstractPointGeometryFieldMapper.Builder<Builder, GeoPointFieldType> {
 
         public Builder(String name) {
@@ -105,6 +112,11 @@ public GeoPointFieldMapper build(
         }
     }
 
+    /**
+     * Concrete parser for geo_point types
+     *
+     * @opensearch.internal
+     */
     public static class TypeParser extends AbstractPointGeometryFieldMapper.TypeParser<Builder> {
         @Override
         protected Builder newBuilder(String name, Map<String, Object> params) {
@@ -187,6 +199,11 @@ public GeoPointFieldType fieldType() {
         return (GeoPointFieldType) mappedFieldType;
     }
 
+    /**
+     * Concrete field type for geo_point
+     *
+     * @opensearch.internal
+     */
     public static class GeoPointFieldType extends AbstractPointGeometryFieldType<List<ParsedGeoPoint>, List<? extends GeoPoint>>
         implements
             GeoShapeQueryable {
@@ -240,6 +257,11 @@ public Query distanceFeatureQuery(Object origin, String pivot, float boost, Quer
 
     // Eclipse requires the AbstractPointGeometryFieldMapper prefix or it can't find ParsedPoint
     // See https://bugs.eclipse.org/bugs/show_bug.cgi?id=565255
+    /**
+     * A geo point parsed from geojson
+     *
+     * @opensearch.internal
+     */
     protected static class ParsedGeoPoint extends GeoPoint implements AbstractPointGeometryFieldMapper.ParsedPoint {
         @Override
         public void validate(String fieldName) {
@@ -297,6 +319,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * The indexer for geo_point
+     *
+     * @opensearch.internal
+     */
     protected static class GeoPointIndexer implements Indexer<List<ParsedGeoPoint>, List<? extends GeoPoint>> {
 
         protected final GeoPointFieldType fieldType;
diff --git a/server/src/main/java/org/opensearch/index/mapper/GeoShapeFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/GeoShapeFieldMapper.java
index e14f26404eb11..4a4b2684b5f4c 100644
--- a/server/src/main/java/org/opensearch/index/mapper/GeoShapeFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/GeoShapeFieldMapper.java
@@ -31,20 +31,28 @@
 
 package org.opensearch.index.mapper;
 
+import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.LatLonShape;
 import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.search.Query;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.geo.GeometryParser;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.geometry.Geometry;
+import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.plain.AbstractGeoShapeIndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.VectorGeoShapeQueryProcessor;
+import org.opensearch.search.aggregations.support.CoreValuesSourceType;
+import org.opensearch.search.lookup.SearchLookup;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Supplier;
 
 /**
  * FieldMapper for indexing {@link LatLonShape}s.
@@ -65,6 +73,8 @@
  * or:
  * <p>
  * "field" : "POLYGON ((100.0 0.0, 101.0 0.0, 101.0 1.0, 100.0 1.0, 100.0 0.0))
+ *
+ * @opensearch.internal
  */
 public class GeoShapeFieldMapper extends AbstractShapeGeometryFieldMapper<Geometry, Geometry> {
     public static final String CONTENT_TYPE = "geo_shape";
@@ -76,11 +86,17 @@ public class GeoShapeFieldMapper extends AbstractShapeGeometryFieldMapper<Geomet
         FIELD_TYPE.freeze();
     }
 
+    /**
+     * Concrete builder for geo_shape types
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends AbstractShapeGeometryFieldMapper.Builder<Builder, GeoShapeFieldType> {
 
         public Builder(String name) {
             super(name, FIELD_TYPE);
-            this.hasDocValues = false;
+            this.hasDocValues = true;
+            builder = this;
         }
 
         private GeoShapeFieldType buildFieldType(BuilderContext context) {
@@ -108,6 +124,11 @@ public GeoShapeFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * Concrete field type for geo_shape fields
+     *
+     * @opensearch.internal
+     */
     public static class GeoShapeFieldType extends AbstractShapeGeometryFieldType<Geometry, Geometry> implements GeoShapeQueryable {
 
         private final VectorGeoShapeQueryProcessor queryProcessor;
@@ -117,6 +138,10 @@ public GeoShapeFieldType(String name, boolean indexed, boolean stored, boolean h
             this.queryProcessor = new VectorGeoShapeQueryProcessor();
         }
 
+        public GeoShapeFieldType(String name) {
+            this(name, true, false, true, Collections.emptyMap());
+        }
+
         @Override
         public String typeName() {
             return CONTENT_TYPE;
@@ -126,8 +151,19 @@ public String typeName() {
         public Query geoShapeQuery(Geometry shape, String fieldName, ShapeRelation relation, QueryShardContext context) {
             return queryProcessor.geoShapeQuery(shape, fieldName, relation, context);
         }
+
+        @Override
+        public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
+            failIfNoDocValues();
+            return new AbstractGeoShapeIndexFieldData.Builder(name(), CoreValuesSourceType.GEO_SHAPE);
+        }
     }
 
+    /**
+     * The type parser
+     *
+     * @opensearch.internal
+     */
     public static final class TypeParser extends AbstractShapeGeometryFieldMapper.TypeParser {
 
         @Override
@@ -163,9 +199,15 @@ protected void addStoredFields(ParseContext context, Geometry geometry) {
     }
 
     @Override
-    @SuppressWarnings("rawtypes")
-    protected void addDocValuesFields(String name, Geometry geometry, List fields, ParseContext context) {
-        // we will throw a mapping exception before we get here
+    protected void addDocValuesFields(
+        final String name,
+        final Geometry geometry,
+        final List<IndexableField> indexableFields,
+        final ParseContext context
+    ) {
+        Field[] fieldsArray = new Field[indexableFields.size()];
+        fieldsArray = indexableFields.toArray(fieldsArray);
+        context.doc().add(LatLonShape.createDocValueField(name, fieldsArray));
     }
 
     @Override
@@ -202,9 +244,4 @@ public GeoShapeFieldType fieldType() {
     protected String contentType() {
         return CONTENT_TYPE;
     }
-
-    @Override
-    protected boolean docValuesByDefault() {
-        return false;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/index/mapper/GeoShapeIndexer.java b/server/src/main/java/org/opensearch/index/mapper/GeoShapeIndexer.java
index 24e458df3a626..166665382a9f4 100644
--- a/server/src/main/java/org/opensearch/index/mapper/GeoShapeIndexer.java
+++ b/server/src/main/java/org/opensearch/index/mapper/GeoShapeIndexer.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.common.geo.GeoLineDecomposer;
 import org.opensearch.common.geo.GeoPolygonDecomposer;
-import org.opensearch.common.geo.GeoShapeUtils;
 import org.opensearch.common.geo.GeoShapeType;
+import org.opensearch.common.geo.GeoShapeUtils;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.geometry.Circle;
 import org.opensearch.geometry.Geometry;
@@ -60,6 +60,8 @@
 
 /**
  * Utility class that converts geometries into Lucene-compatible form for indexing in a geo_shape field.
+ *
+ * @opensearch.internal
  */
 public class GeoShapeIndexer implements AbstractGeometryFieldMapper.Indexer<Geometry, Geometry> {
 
@@ -200,6 +202,11 @@ public List<IndexableField> indexShape(ParseContext context, Geometry shape) {
         return visitor.fields();
     }
 
+    /**
+     * The shape indexer
+     *
+     * @opensearch.internal
+     */
     private static class LuceneGeometryIndexer implements GeometryVisitor<Void, RuntimeException> {
         private List<IndexableField> fields = new ArrayList<>();
         private final String name;
diff --git a/server/src/main/java/org/opensearch/index/mapper/GeoShapeParser.java b/server/src/main/java/org/opensearch/index/mapper/GeoShapeParser.java
index 1ba1d9ee3be59..3006078473afd 100644
--- a/server/src/main/java/org/opensearch/index/mapper/GeoShapeParser.java
+++ b/server/src/main/java/org/opensearch/index/mapper/GeoShapeParser.java
@@ -35,10 +35,10 @@
 import org.opensearch.common.geo.GeometryFormat;
 import org.opensearch.common.geo.GeometryParser;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.common.xcontent.support.MapXContentParser;
+import org.opensearch.core.xcontent.MapXContentParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 
 import java.io.IOException;
@@ -46,6 +46,11 @@
 import java.text.ParseException;
 import java.util.Collections;
 
+/**
+ * Utility class that parses geo shapes
+ *
+ * @opensearch.internal
+ */
 public class GeoShapeParser extends AbstractGeometryFieldMapper.Parser<Geometry> {
     private final GeometryParser geometryParser;
 
@@ -70,7 +75,7 @@ public Object parseAndFormatObject(Object value, String format) {
                 NamedXContentRegistry.EMPTY,
                 LoggingDeprecationHandler.INSTANCE,
                 Collections.singletonMap("dummy_field", value),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             parser.nextToken(); // start object
diff --git a/server/src/main/java/org/opensearch/index/mapper/GeoShapeQueryable.java b/server/src/main/java/org/opensearch/index/mapper/GeoShapeQueryable.java
index 7fc6f3cd7c6c6..fbcba13b3676d 100644
--- a/server/src/main/java/org/opensearch/index/mapper/GeoShapeQueryable.java
+++ b/server/src/main/java/org/opensearch/index/mapper/GeoShapeQueryable.java
@@ -41,6 +41,8 @@
 /**
  * Implemented by {@link org.opensearch.index.mapper.MappedFieldType} that support
  * GeoShape queries.
+ *
+ * @opensearch.internal
  */
 public interface GeoShapeQueryable {
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/IdFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/IdFieldMapper.java
index 7ca7b9e81be96..38d25de8ff808 100644
--- a/server/src/main/java/org/opensearch/index/mapper/IdFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/IdFieldMapper.java
@@ -44,6 +44,7 @@
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
@@ -54,7 +55,6 @@
 import org.opensearch.index.fielddata.plain.PagedBytesIndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
@@ -73,6 +73,8 @@
  * A mapper for the _id field. It does nothing since _id is neither indexed nor
  * stored, but we need to keep it so that its FieldType can be used to generate
  * queries.
+ *
+ * @opensearch.internal
  */
 public class IdFieldMapper extends MetadataFieldMapper {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(IdFieldMapper.class);
@@ -85,6 +87,11 @@ public class IdFieldMapper extends MetadataFieldMapper {
 
     public static final String CONTENT_TYPE = "_id";
 
+    /**
+     * Default parameters
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final String NAME = IdFieldMapper.NAME;
 
@@ -110,6 +117,11 @@ public static class Defaults {
 
     public static final TypeParser PARSER = new FixedTypeParser(c -> new IdFieldMapper(() -> c.mapperService().isIdFieldDataEnabled()));
 
+    /**
+     * Field type for ID field
+     *
+     * @opensearch.internal
+     */
     static final class IdFieldType extends TermBasedFieldType {
 
         private final Supplier<Boolean> fieldDataEnabled;
diff --git a/server/src/main/java/org/opensearch/index/mapper/IgnoredFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/IgnoredFieldMapper.java
index 0d82b20cfaea6..0db795d99c7e0 100644
--- a/server/src/main/java/org/opensearch/index/mapper/IgnoredFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/IgnoredFieldMapper.java
@@ -44,6 +44,8 @@
 
 /**
  * A field mapper that records fields that have been ignored because they were malformed.
+ *
+ * @opensearch.internal
  */
 public final class IgnoredFieldMapper extends MetadataFieldMapper {
 
@@ -51,6 +53,11 @@ public final class IgnoredFieldMapper extends MetadataFieldMapper {
 
     public static final String CONTENT_TYPE = "_ignored";
 
+    /**
+     * Default parameters
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final String NAME = IgnoredFieldMapper.NAME;
 
@@ -67,6 +74,11 @@ public static class Defaults {
 
     public static final TypeParser PARSER = new FixedTypeParser(c -> new IgnoredFieldMapper());
 
+    /**
+     * Field type for Ignored fields
+     *
+     * @opensearch.internal
+     */
     public static final class IgnoredFieldType extends StringFieldType {
 
         public static final IgnoredFieldType INSTANCE = new IgnoredFieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/IndexFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/IndexFieldMapper.java
index ae32aa52162fe..982b0eb909443 100644
--- a/server/src/main/java/org/opensearch/index/mapper/IndexFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/IndexFieldMapper.java
@@ -34,7 +34,7 @@
 
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.plain.ConstantIndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
@@ -44,6 +44,11 @@
 import java.util.Collections;
 import java.util.function.Supplier;
 
+/**
+ * Index specific field mapper
+ *
+ * @opensearch.internal
+ */
 public class IndexFieldMapper extends MetadataFieldMapper {
 
     public static final String NAME = "_index";
@@ -52,6 +57,11 @@ public class IndexFieldMapper extends MetadataFieldMapper {
 
     public static final TypeParser PARSER = new FixedTypeParser(c -> new IndexFieldMapper());
 
+    /**
+     * Field type for Index field mapper
+     *
+     * @opensearch.internal
+     */
     static final class IndexFieldType extends ConstantFieldType {
 
         static final IndexFieldType INSTANCE = new IndexFieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/IpFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/IpFieldMapper.java
index 3ba5e1e0dfe35..2a677d8bc1352 100644
--- a/server/src/main/java/org/opensearch/index/mapper/IpFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/IpFieldMapper.java
@@ -63,7 +63,11 @@
 import java.util.function.BiFunction;
 import java.util.function.Supplier;
 
-/** A {@link FieldMapper} for ip addresses. */
+/**
+ * A {@link FieldMapper} for ip addresses.
+ *
+ * @opensearch.internal
+ */
 public class IpFieldMapper extends ParametrizedFieldMapper {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(IpFieldMapper.class);
@@ -74,6 +78,11 @@ private static IpFieldMapper toType(FieldMapper in) {
         return (IpFieldMapper) in;
     }
 
+    /**
+     * Builder
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> indexed = Parameter.indexParam(m -> toType(m).indexed, true);
@@ -151,6 +160,11 @@ public IpFieldMapper build(BuilderContext context) {
         return new Builder(n, ignoreMalformedByDefault, c.indexVersionCreated());
     });
 
+    /**
+     * Field type for IP fields
+     *
+     * @opensearch.internal
+     */
     public static final class IpFieldType extends SimpleMappedFieldType {
 
         private final InetAddress nullValue;
@@ -301,6 +315,11 @@ public static Query rangeQuery(
             return builder.apply(lower, upper);
         }
 
+        /**
+         * Field type for IP Scripted doc values
+         *
+         * @opensearch.internal
+         */
         public static final class IpScriptDocValues extends ScriptDocValues<String> {
 
             private final SortedSetDocValues in;
diff --git a/server/src/main/java/org/opensearch/index/mapper/KeywordFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/KeywordFieldMapper.java
index 4206b29e23456..92ee8067ee4a0 100644
--- a/server/src/main/java/org/opensearch/index/mapper/KeywordFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/KeywordFieldMapper.java
@@ -38,9 +38,12 @@
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.search.MultiTermQuery;
+import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.Nullable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.fielddata.IndexFieldData;
@@ -61,11 +64,18 @@
 
 /**
  * A field mapper for keywords. This mapper accepts strings and indexes them as-is.
+ *
+ * @opensearch.internal
  */
 public final class KeywordFieldMapper extends ParametrizedFieldMapper {
 
     public static final String CONTENT_TYPE = "keyword";
 
+    /**
+     * Default parameters
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final FieldType FIELD_TYPE = new FieldType();
 
@@ -77,6 +87,11 @@ public static class Defaults {
         }
     }
 
+    /**
+     * The keyword field for the field mapper
+     *
+     * @opensearch.internal
+     */
     public static class KeywordField extends Field {
 
         public KeywordField(String field, BytesRef term, FieldType ft) {
@@ -89,6 +104,11 @@ private static KeywordFieldMapper toType(FieldMapper in) {
         return (KeywordFieldMapper) in;
     }
 
+    /**
+     * The builder for the field mapper
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> indexed = Parameter.indexParam(m -> toType(m).indexed, true);
@@ -223,6 +243,11 @@ public KeywordFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n, c.getIndexAnalyzers()));
 
+    /**
+     * Field type for keyword fields
+     *
+     * @opensearch.internal
+     */
     public static final class KeywordFieldType extends StringFieldType {
 
         private final int ignoreAbove;
@@ -346,6 +371,18 @@ protected BytesRef indexedValueForSearch(Object value) {
             }
             return getTextSearchInfo().getSearchAnalyzer().normalize(name(), value.toString());
         }
+
+        @Override
+        public Query wildcardQuery(
+            String value,
+            @Nullable MultiTermQuery.RewriteMethod method,
+            boolean caseInsensitve,
+            QueryShardContext context
+        ) {
+            // keyword field types are always normalized, so ignore case sensitivity and force normalize the wildcard
+            // query text
+            return super.wildcardQuery(value, method, caseInsensitve, true, context);
+        }
     }
 
     private final boolean indexed;
diff --git a/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapper.java
index b8595647c328c..7868edabb9847 100644
--- a/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapper.java
@@ -44,8 +44,8 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Explicit;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.geo.GeometryParser;
 import org.opensearch.common.geo.ShapeRelation;
@@ -58,13 +58,13 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.index.query.LegacyGeoShapeQueryProcessor;
 import org.opensearch.index.query.QueryShardContext;
-import org.locationtech.spatial4j.shape.Shape;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -72,6 +72,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.locationtech.spatial4j.shape.Shape;
+
 /**
  * FieldMapper for indexing {@link org.locationtech.spatial4j.shape.Shape}s.
  * <p>
@@ -93,14 +95,26 @@
  * "field" : "POLYGON ((100.0 0.0, 101.0 0.0, 101.0 1.0, 100.0 1.0, 100.0 0.0))
  *
  * @deprecated use {@link GeoShapeFieldMapper}
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public class LegacyGeoShapeFieldMapper extends AbstractShapeGeometryFieldMapper<ShapeBuilder<?, ?, ?>, Shape> {
 
     public static final String CONTENT_TYPE = "geo_shape";
 
+    /**
+     * Legacy prefix tree parameters that are now deprecated
+     *
+     * @opensearch.internal
+     */
     @Deprecated
     public static class DeprecatedParameters {
+        /**
+         * Deprecated parameter names for Prefix trees
+         *
+         * @opensearch.internal
+         */
         public static class Names {
             public static final ParseField STRATEGY = new ParseField("strategy");
             public static final ParseField TREE = new ParseField("tree");
@@ -110,12 +124,22 @@ public static class Names {
             public static final ParseField POINTS_ONLY = new ParseField("points_only");
         }
 
+        /**
+         * Deprecated prefix tree types
+         *
+         * @opensearch.internal
+         */
         public static class PrefixTrees {
             public static final String LEGACY_QUADTREE = "legacyquadtree";
             public static final String QUADTREE = "quadtree";
             public static final String GEOHASH = "geohash";
         }
 
+        /**
+         * Deprecated defaults for legacy prefix trees
+         *
+         * @opensearch.internal
+         */
         public static class Defaults {
             public static final SpatialStrategy STRATEGY = SpatialStrategy.RECURSIVE;
             public static final String TREE = "quadtree";
@@ -201,6 +225,11 @@ private static void checkPrefixTreeSupport(String fieldName) {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(LegacyGeoShapeFieldMapper.class);
 
+    /**
+     * The builder for the deprecated prefix tree implementation
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends AbstractShapeGeometryFieldMapper.Builder<Builder, LegacyGeoShapeFieldMapper.GeoShapeFieldType> {
 
         DeprecatedParameters deprecatedParameters;
@@ -323,6 +352,11 @@ public LegacyGeoShapeFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * A legacy parser for prefix trees
+     *
+     * @opensearch.internal
+     */
     private static class LegacyGeoShapeParser extends Parser<ShapeBuilder<?, ?, ?>> {
         /**
          * Note that this parser is only used for formatting values.
@@ -345,6 +379,11 @@ public Object format(ShapeBuilder<?, ?, ?> value, String format) {
         }
     }
 
+    /**
+     * Field type for GeoShape fields
+     *
+     * @opensearch.internal
+     */
     public static final class GeoShapeFieldType extends AbstractShapeGeometryFieldType<ShapeBuilder<?, ?, ?>, Shape>
         implements
             GeoShapeQueryable {
@@ -483,7 +522,7 @@ public LegacyGeoShapeFieldMapper(
         CopyTo copyTo
     ) {
         super(simpleName, fieldType, mappedFieldType, ignoreMalformed, coerce, ignoreZValue, orientation, multiFields, copyTo);
-        this.indexCreatedVersion = Version.indexCreated(indexSettings);
+        this.indexCreatedVersion = IndexMetadata.indexCreated(indexSettings);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeIndexer.java b/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeIndexer.java
index d5342c2510100..5f12cb59ebe7a 100644
--- a/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeIndexer.java
+++ b/server/src/main/java/org/opensearch/index/mapper/LegacyGeoShapeIndexer.java
@@ -35,14 +35,23 @@
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.common.geo.XShapeCollection;
 import org.opensearch.common.geo.builders.ShapeBuilder;
-import org.locationtech.spatial4j.shape.Point;
-import org.locationtech.spatial4j.shape.Shape;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.locationtech.spatial4j.shape.Point;
+import org.locationtech.spatial4j.shape.Shape;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
+/**
+ * Indexer for legacy prefix trees
+ *
+ * @opensearch.internal
+ *
+ * @deprecated will be removed in the next version
+ */
+@Deprecated
 public class LegacyGeoShapeIndexer implements AbstractGeometryFieldMapper.Indexer<ShapeBuilder<?, ?, ?>, Shape> {
 
     private LegacyGeoShapeFieldMapper.GeoShapeFieldType fieldType;
diff --git a/server/src/main/java/org/opensearch/index/mapper/MappedFieldType.java b/server/src/main/java/org/opensearch/index/mapper/MappedFieldType.java
index 645115bfe26e2..58aa0bb2576e2 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MappedFieldType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MappedFieldType.java
@@ -51,6 +51,7 @@
 import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.geo.ShapeRelation;
@@ -77,6 +78,8 @@
 
 /**
  * This defines the core properties and functions to operate on a field.
+ *
+ * @opensearch.internal
  */
 public abstract class MappedFieldType {
 
@@ -114,7 +117,7 @@ public MappedFieldType(
      * @param searchLookup a {@link SearchLookup} supplier to allow for accessing other fields values in the context of runtime fields
      * @throws IllegalArgumentException if the fielddata is not supported on this type.
      * An IllegalArgumentException is needed in order to return an http error 400
-     * when this error occurs in a request. see: {@link org.opensearch.ExceptionsHelper#status}
+     * when this error occurs in a request. see: {@link ExceptionsHelper#status}
      */
     public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
         throw new IllegalArgumentException("Fielddata is not supported on field [" + name() + "] of type [" + typeName() + "]");
@@ -279,7 +282,7 @@ public Query prefixQuery(
     ) {
         throw new QueryShardException(
             context,
-            "Can only use prefix queries on keyword, text and wildcard fields - not on [" + name + "] which is of type [" + typeName() + "]"
+            "Can only use prefix queries on keyword and text fields - not on [" + name + "] which is of type [" + typeName() + "]"
         );
     }
 
@@ -288,6 +291,7 @@ public final Query wildcardQuery(String value, @Nullable MultiTermQuery.RewriteM
         return wildcardQuery(value, method, false, context);
     }
 
+    /** optionally normalize the wildcard pattern based on the value of {@code caseInsensitive} */
     public Query wildcardQuery(
         String value,
         @Nullable MultiTermQuery.RewriteMethod method,
@@ -296,11 +300,15 @@ public Query wildcardQuery(
     ) {
         throw new QueryShardException(
             context,
-            "Can only use wildcard queries on keyword, text and wildcard fields - not on ["
-                + name
-                + "] which is of type ["
-                + typeName()
-                + "]"
+            "Can only use wildcard queries on keyword and text fields - not on [" + name + "] which is of type [" + typeName() + "]"
+        );
+    }
+
+    /** always normalizes the wildcard pattern to lowercase */
+    public Query normalizedWildcardQuery(String value, @Nullable MultiTermQuery.RewriteMethod method, QueryShardContext context) {
+        throw new QueryShardException(
+            context,
+            "Can only use wildcard queries on keyword and text fields - not on [" + name + "] which is of type [" + typeName() + "]"
         );
     }
 
@@ -376,6 +384,8 @@ public IntervalsSource intervals(String query, int max_gaps, IntervalMode mode,
     /**
      * An enum used to describe the relation between the range of terms in a
      * shard when compared with a query range
+     *
+     * @opensearch.internal
      */
     public enum Relation {
         WITHIN,
@@ -402,7 +412,7 @@ public Relation isFieldWithinQuery(
 
     /** @throws IllegalArgumentException if the fielddata is not supported on this type.
      *  An IllegalArgumentException is needed in order to return an http error 400
-     *  when this error occurs in a request. see: {@link org.opensearch.ExceptionsHelper#status}
+     *  when this error occurs in a request. see: {@link ExceptionsHelper#status}
      **/
     protected final void failIfNoDocValues() {
         if (hasDocValues() == false) {
diff --git a/server/src/main/java/org/opensearch/index/mapper/Mapper.java b/server/src/main/java/org/opensearch/index/mapper/Mapper.java
index f9f16a33a0c52..59c647d38f0de 100644
--- a/server/src/main/java/org/opensearch/index/mapper/Mapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/Mapper.java
@@ -37,7 +37,7 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentFragment;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.similarity.SimilarityProvider;
@@ -48,8 +48,18 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
+/**
+ * The foundation OpenSearch mapper
+ *
+ * @opensearch.internal
+ */
 public abstract class Mapper implements ToXContentFragment, Iterable<Mapper> {
 
+    /**
+     * The builder context used in field mappings
+     *
+     * @opensearch.internal
+     */
     public static class BuilderContext {
         private final Settings indexSettings;
         private final ContentPath contentPath;
@@ -69,7 +79,7 @@ public Settings indexSettings() {
         }
 
         public Version indexCreatedVersion() {
-            return Version.indexCreated(indexSettings);
+            return IndexMetadata.indexCreated(indexSettings);
         }
 
         public Version indexCreatedVersionOrDefault(@Nullable Version defaultValue) {
@@ -81,6 +91,11 @@ public Version indexCreatedVersionOrDefault(@Nullable Version defaultValue) {
         }
     }
 
+    /**
+     * Base mapper builder
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder<T extends Builder> {
 
         public String name;
@@ -99,8 +114,18 @@ public String name() {
         public abstract Mapper build(BuilderContext context);
     }
 
+    /**
+     * Type parser for the mapper
+     *
+     * @opensearch.internal
+     */
     public interface TypeParser {
 
+        /**
+         * Parser context for the type parser
+         *
+         * @opensearch.internal
+         */
         class ParserContext {
 
             private final Function<String, SimilarityProvider> similarityLookupService;
@@ -195,6 +220,11 @@ public ParserContext createMultiFieldContext(ParserContext in) {
                 return new MultiFieldParserContext(in);
             }
 
+            /**
+             * Base mutiple field parser context
+             *
+             * @opensearch.internal
+             */
             static class MultiFieldParserContext extends ParserContext {
                 MultiFieldParserContext(ParserContext in) {
                     super(
diff --git a/server/src/main/java/org/opensearch/index/mapper/MapperException.java b/server/src/main/java/org/opensearch/index/mapper/MapperException.java
index 0276aa6431c6d..75ef3c9a56be5 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MapperException.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MapperException.java
@@ -33,10 +33,15 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown for any mapping errors
+ *
+ * @opensearch.internal
+ */
 public class MapperException extends OpenSearchException {
     public MapperException(StreamInput in) throws IOException {
         super(in);
diff --git a/server/src/main/java/org/opensearch/index/mapper/MapperParsingException.java b/server/src/main/java/org/opensearch/index/mapper/MapperParsingException.java
index dafe1e165038b..7dff82e2e3167 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MapperParsingException.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MapperParsingException.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there are any errors parsing mappings
+ *
+ * @opensearch.internal
+ */
 public class MapperParsingException extends MapperException {
 
     public MapperParsingException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/index/mapper/MapperService.java b/server/src/main/java/org/opensearch/index/mapper/MapperService.java
index a92647929ff08..25809fd3e57e8 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MapperService.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MapperService.java
@@ -35,12 +35,10 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.DelegatingAnalyzerWrapper;
-import org.opensearch.Assertions;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
@@ -48,11 +46,13 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.AbstractIndexComponent;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalysisRegistry;
@@ -87,14 +87,21 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * The core field mapping service
+ *
+ * @opensearch.internal
+ */
 public class MapperService extends AbstractIndexComponent implements Closeable {
 
     /**
      * The reason why a mapping is being merged.
+     *
+     * @opensearch.internal
      */
     public enum MergeReason {
         /**
-         * Pre-flight check before sending a mapping update to the master
+         * Pre-flight check before sending a mapping update to the cluster-manager
          */
         MAPPING_UPDATE_PREFLIGHT,
         /**
@@ -166,9 +173,6 @@ public enum MergeReason {
     );
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(MapperService.class);
-    static final String DEFAULT_MAPPING_ERROR_MESSAGE = "[_default_] mappings are not allowed on new indices and should no "
-        + "longer be used. See [https://www.elastic.co/guide/en/elasticsearch/reference/current/breaking-changes-7.0.html"
-        + "#default-mapping-not-allowed] for more information.";
 
     private final IndexAnalyzers indexAnalyzers;
 
@@ -248,7 +252,7 @@ public DocumentMapperParser documentMapperParser() {
      */
     public static Map<String, Object> parseMapping(NamedXContentRegistry xContentRegistry, String mappingSource) throws IOException {
         try (
-            XContentParser parser = XContentType.JSON.xContent()
+            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                 .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, mappingSource)
         ) {
             return parser.map();
@@ -303,7 +307,7 @@ public boolean updateMapping(final IndexMetadata currentIndexMetadata, final Ind
             }
 
             // refresh mapping can happen when the parsing/merging of the mapping from the metadata doesn't result in the same
-            // mapping, in this case, we send to the master to refresh its own version of the mappings (to conform with the
+            // mapping, in this case, we send to the cluster-manager to refresh its own version of the mappings (to conform with the
             // merge version of it, which it does when refreshing the mappings), and warn log it.
             if (documentMapper().mappingSource().equals(incomingMappingSource) == false) {
                 logger.debug(
@@ -343,7 +347,7 @@ private void assertMappingVersion(
                         + "to be the same as new mapping ["
                         + newSource
                         + "]";
-                    final CompressedXContent mapperSource = new CompressedXContent(Strings.toString(mapper));
+                    final CompressedXContent mapperSource = new CompressedXContent(Strings.toString(MediaTypeRegistry.JSON, mapper));
                     assert currentSource.equals(mapperSource) : "expected current mapping ["
                         + currentSource
                         + "] for type ["
@@ -389,7 +393,7 @@ public void merge(Map<String, Map<String, Object>> mappings, MergeReason reason)
             try {
                 mappingSourcesCompressed.put(
                     entry.getKey(),
-                    new CompressedXContent(Strings.toString(XContentFactory.jsonBuilder().map(entry.getValue())))
+                    new CompressedXContent(XContentFactory.jsonBuilder().map(entry.getValue()).toString())
                 );
             } catch (Exception e) {
                 throw new MapperParsingException("Failed to parse mapping [{}]: {}", e, entry.getKey(), e.getMessage());
@@ -400,7 +404,7 @@ public void merge(Map<String, Map<String, Object>> mappings, MergeReason reason)
     }
 
     public void merge(String type, Map<String, Object> mappings, MergeReason reason) throws IOException {
-        CompressedXContent content = new CompressedXContent(Strings.toString(XContentFactory.jsonBuilder().map(mappings)));
+        CompressedXContent content = new CompressedXContent(XContentFactory.jsonBuilder().map(mappings).toString());
         internalMerge(Collections.singletonMap(type, content), reason);
     }
 
@@ -538,7 +542,7 @@ public static boolean isMappingSourceTyped(String type, Map<String, Object> mapp
     }
 
     public static boolean isMappingSourceTyped(String type, CompressedXContent mappingSource) {
-        Map<String, Object> root = XContentHelper.convertToMap(mappingSource.compressedReference(), true, XContentType.JSON).v2();
+        Map<String, Object> root = XContentHelper.convertToMap(mappingSource.compressedReference(), true, MediaTypeRegistry.JSON).v2();
         return isMappingSourceTyped(type, root);
     }
 
@@ -576,11 +580,6 @@ public DocumentMapperForType documentMapperWithAutoCreate() {
      * Given the full name of a field, returns its {@link MappedFieldType}.
      */
     public MappedFieldType fieldType(String fullName) {
-        if (fullName.equals(TypeFieldMapper.NAME)) {
-            String type = mapper == null ? null : mapper.type();
-            return new TypeFieldMapper.TypeFieldType(type);
-        }
-
         return this.mapper == null ? null : this.mapper.fieldTypes().get(fullName);
     }
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/Mapping.java b/server/src/main/java/org/opensearch/index/mapper/Mapping.java
index 90d6c6a2ddcc0..d68d1e62e2f92 100644
--- a/server/src/main/java/org/opensearch/index/mapper/Mapping.java
+++ b/server/src/main/java/org/opensearch/index/mapper/Mapping.java
@@ -33,12 +33,11 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 
 import java.io.IOException;
@@ -54,6 +53,8 @@
 /**
  * Wrapper around everything that defines a mapping, without references to
  * utility classes like MapperService, ...
+ *
+ * @opensearch.internal
  */
 public final class Mapping implements ToXContentFragment {
 
@@ -183,7 +184,7 @@ public String toString() {
         try {
             XContentBuilder builder = XContentFactory.jsonBuilder().startObject();
             toXContent(builder, new ToXContent.MapParams(emptyMap()));
-            return Strings.toString(builder.endObject());
+            return builder.endObject().toString();
         } catch (IOException bogus) {
             throw new UncheckedIOException(bogus);
         }
diff --git a/server/src/main/java/org/opensearch/index/mapper/MappingLookup.java b/server/src/main/java/org/opensearch/index/mapper/MappingLookup.java
index 38f825e18904d..024f4b71584bf 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MappingLookup.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MappingLookup.java
@@ -33,6 +33,7 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.analysis.Analyzer;
+import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.FieldNameAnalyzer;
 
@@ -45,6 +46,11 @@
 import java.util.Map;
 import java.util.stream.Stream;
 
+/**
+ * Looks up a mapping for a field
+ *
+ * @opensearch.internal
+ */
 public final class MappingLookup implements Iterable<Mapper> {
 
     /** Full field name to mapper */
@@ -256,6 +262,15 @@ public String getNestedScope(String path) {
         return null;
     }
 
+    /**
+     * If this index contains @timestamp field with Date type, it will return true
+     * @return true or false based on above condition
+     */
+    public boolean containsTimeStampField() {
+        MappedFieldType timeSeriesFieldType = this.fieldTypeLookup.get(DataStream.TIMESERIES_FIELDNAME);
+        return timeSeriesFieldType != null && timeSeriesFieldType instanceof DateFieldMapper.DateFieldType; // has to be Date field type
+    }
+
     private static String parentObject(String field) {
         int lastDot = field.lastIndexOf('.');
         if (lastDot == -1) {
diff --git a/server/src/main/java/org/opensearch/index/mapper/MetadataFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/MetadataFieldMapper.java
index 7fca0610c046d..4f5aefdfeed55 100644
--- a/server/src/main/java/org/opensearch/index/mapper/MetadataFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/MetadataFieldMapper.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.common.Explicit;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
@@ -42,9 +42,16 @@
 
 /**
  * A mapper for a builtin field containing metadata about a document.
+ *
+ * @opensearch.internal
  */
 public abstract class MetadataFieldMapper extends ParametrizedFieldMapper {
 
+    /**
+     * Type parser for the field mapper
+     *
+     * @opensearch.internal
+     */
     public interface TypeParser extends Mapper.TypeParser {
 
         @Override
@@ -89,6 +96,8 @@ public static Parameter<Explicit<Boolean>> updateableBoolParam(
 
     /**
      * A type parser for an unconfigurable metadata field.
+     *
+     * @opensearch.internal
      */
     public static class FixedTypeParser implements TypeParser {
 
@@ -109,6 +118,11 @@ public MetadataFieldMapper getDefault(MappedFieldType defaultFieldType, ParserCo
         }
     }
 
+    /**
+     * Type parser that is configurable
+     *
+     * @opensearch.internal
+     */
     public static class ConfigurableTypeParser implements TypeParser {
 
         final Function<ParserContext, MetadataFieldMapper> defaultMapperParser;
@@ -135,6 +149,11 @@ public MetadataFieldMapper getDefault(MappedFieldType defaultFieldType, ParserCo
         }
     }
 
+    /**
+     * Base builder for internal metadata fields
+     *
+     * @opensearch.internal
+     */
     public abstract static class Builder extends ParametrizedFieldMapper.Builder {
 
         protected Builder(String name) {
diff --git a/server/src/main/java/org/opensearch/index/mapper/NestedPathFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/NestedPathFieldMapper.java
new file mode 100644
index 0000000000000..06db3fd38c062
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/mapper/NestedPathFieldMapper.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.FieldType;
+import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.Version;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.search.lookup.SearchLookup;
+
+import java.util.Collections;
+
+/**
+ * Replacement for TypesFieldMapper used in nested fields
+ *
+ * @opensearch.internal
+ */
+public class NestedPathFieldMapper extends MetadataFieldMapper {
+    // OpenSearch version 2.0 removed types; this name is used for bwc
+    public static final String LEGACY_NAME = "_type";
+    public static final String NAME = "_nested_path";
+
+    /**
+     * Default parameters for the field mapper
+     *
+     * @opensearch.internal
+     */
+    public static class Defaults {
+        public static final FieldType FIELD_TYPE = new FieldType();
+        static {
+            FIELD_TYPE.setIndexOptions(IndexOptions.DOCS);
+            FIELD_TYPE.setTokenized(false);
+            FIELD_TYPE.setStored(false);
+            FIELD_TYPE.setOmitNorms(true);
+            FIELD_TYPE.freeze();
+        }
+    }
+
+    /** private ctor; using SINGLETON to control BWC */
+    private NestedPathFieldMapper(String name) {
+        super(new NestedPathFieldType(name));
+    }
+
+    /** returns the field name */
+    public static String name(Version version) {
+        if (version.before(Version.V_2_0_0)) {
+            return LEGACY_NAME;
+        }
+        return NAME;
+    }
+
+    @Override
+    protected String contentType() {
+        return NAME;
+    }
+
+    private static final NestedPathFieldMapper LEGACY_INSTANCE = new NestedPathFieldMapper(LEGACY_NAME);
+    private static final NestedPathFieldMapper INSTANCE = new NestedPathFieldMapper(NAME);
+
+    public static final TypeParser PARSER = new FixedTypeParser(
+        c -> c.indexVersionCreated().before(Version.V_2_0_0) ? LEGACY_INSTANCE : INSTANCE
+    );
+
+    /** helper method to create a lucene field based on the opensearch version */
+    public static Field field(Version version, String path) {
+        return new Field(name(version), path, Defaults.FIELD_TYPE);
+    }
+
+    /** helper method to create a query based on the opensearch version */
+    public static Query filter(Version version, String path) {
+        return new TermQuery(new Term(name(version), new BytesRef(path)));
+    }
+
+    /**
+     * field type for the NestPath field
+     *
+     * @opensearch.internal
+     */
+    public static final class NestedPathFieldType extends StringFieldType {
+        private NestedPathFieldType(String name) {
+            super(name, true, false, false, TextSearchInfo.SIMPLE_MATCH_ONLY, Collections.emptyMap());
+        }
+
+        @Override
+        public String typeName() {
+            return NAME;
+        }
+
+        @Override
+        public Query existsQuery(QueryShardContext context) {
+            throw new UnsupportedOperationException("Cannot run exists() query against the nested field path");
+        }
+
+        @Override
+        public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchLookup, String format) {
+            throw new UnsupportedOperationException("Cannot fetch values for internal field [" + name() + "].");
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/mapper/NumberFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/NumberFieldMapper.java
index bf7b1ae70c711..204e7bc4c16ab 100644
--- a/server/src/main/java/org/opensearch/index/mapper/NumberFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/NumberFieldMapper.java
@@ -34,6 +34,7 @@
 
 import com.fasterxml.jackson.core.JsonParseException;
 import com.fasterxml.jackson.core.exc.InputCoercionException;
+
 import org.apache.lucene.document.DoublePoint;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FloatPoint;
@@ -41,10 +42,11 @@
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.StoredField;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
 import org.apache.lucene.sandbox.document.HalfFloatPoint;
-import org.apache.lucene.sandbox.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
+import org.apache.lucene.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
@@ -56,8 +58,9 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
+import org.opensearch.index.document.SortedUnsignedLongDocValuesRangeQuery;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData.NumericType;
 import org.opensearch.index.fielddata.plain.SortedNumericIndexFieldData;
@@ -66,6 +69,7 @@
 import org.opensearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.time.ZoneId;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -77,7 +81,11 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
-/** A {@link FieldMapper} for numeric types: byte, short, int, long, float and double. */
+/**
+ * A {@link FieldMapper} for numeric types: byte, short, int, long, float and double.
+ *
+ * @opensearch.internal
+ */
 public class NumberFieldMapper extends ParametrizedFieldMapper {
 
     public static final Setting<Boolean> COERCE_SETTING = Setting.boolSetting("index.mapping.coerce", true, Property.IndexScope);
@@ -86,6 +94,11 @@ private static NumberFieldMapper toType(FieldMapper in) {
         return (NumberFieldMapper) in;
     }
 
+    /**
+     * Builder for the number field mappers
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> indexed = Parameter.indexParam(m -> toType(m).indexed, true);
@@ -152,6 +165,11 @@ public NumberFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * Type of number
+     *
+     * @opensearch.internal
+     */
     public enum NumberType {
         HALF_FLOAT("half_float", NumericType.HALF_FLOAT) {
             @Override
@@ -250,6 +268,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
                 return fields;
             }
 
+            @Override
+            Number valueForSearch(String value) {
+                return Float.parseFloat(value);
+            }
+
             private void validateParsed(float value) {
                 if (!Float.isFinite(HalfFloatPoint.sortableShortToHalfFloat(HalfFloatPoint.halfFloatToSortableShort(value)))) {
                     throw new IllegalArgumentException("[half_float] supports only finite values, but got [" + value + "]");
@@ -351,6 +374,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
                 return fields;
             }
 
+            @Override
+            Number valueForSearch(String value) {
+                return Float.parseFloat(value);
+            }
+
             private void validateParsed(float value) {
                 if (!Float.isFinite(value)) {
                     throw new IllegalArgumentException("[float] supports only finite values, but got [" + value + "]");
@@ -431,6 +459,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
                 return fields;
             }
 
+            @Override
+            Number valueForSearch(String value) {
+                return Double.parseDouble(value);
+            }
+
             private void validateParsed(double value) {
                 if (!Double.isFinite(value)) {
                     throw new IllegalArgumentException("[double] supports only finite values, but got [" + value + "]");
@@ -502,6 +535,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
             Number valueForSearch(Number value) {
                 return value.byteValue();
             }
+
+            @Override
+            Number valueForSearch(String value) {
+                return Byte.parseByte(value);
+            }
         },
         SHORT("short", NumericType.SHORT) {
             @Override
@@ -564,6 +602,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
             Number valueForSearch(Number value) {
                 return value.shortValue();
             }
+
+            @Override
+            Number valueForSearch(String value) {
+                return Short.parseShort(value);
+            }
         },
         INTEGER("integer", NumericType.INT) {
             @Override
@@ -686,6 +729,11 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
                 }
                 return fields;
             }
+
+            @Override
+            Number valueForSearch(String value) {
+                return Integer.parseInt(value);
+            }
         },
         LONG("long", NumericType.LONG) {
             @Override
@@ -770,6 +818,103 @@ public List<Field> createFields(String name, Number value, boolean indexed, bool
                 }
                 return fields;
             }
+
+            @Override
+            Number valueForSearch(String value) {
+                return Long.parseLong(value);
+            }
+        },
+        UNSIGNED_LONG("unsigned_long", NumericType.UNSIGNED_LONG) {
+            @Override
+            public BigInteger parse(Object value, boolean coerce) {
+                return objectToUnsignedLong(value, coerce);
+            }
+
+            @Override
+            public Number parsePoint(byte[] value) {
+                return BigIntegerPoint.decodeDimension(value, 0);
+            }
+
+            @Override
+            public BigInteger parse(XContentParser parser, boolean coerce) throws IOException {
+                return parser.bigIntegerValue(coerce);
+            }
+
+            @Override
+            public Query termQuery(String field, Object value) {
+                if (hasDecimalPart(value)) {
+                    return Queries.newMatchNoDocsQuery("Value [" + value + "] has a decimal part");
+                }
+                BigInteger v = parse(value, true);
+                return BigIntegerPoint.newExactQuery(field, v);
+            }
+
+            @Override
+            public Query termsQuery(String field, List<Object> values) {
+                BigInteger[] v = new BigInteger[values.size()];
+                int upTo = 0;
+
+                for (int i = 0; i < values.size(); i++) {
+                    Object value = values.get(i);
+                    if (!hasDecimalPart(value)) {
+                        v[upTo++] = parse(value, true);
+                    }
+                }
+
+                if (upTo == 0) {
+                    return Queries.newMatchNoDocsQuery("All values have a decimal part");
+                }
+                if (upTo != v.length) {
+                    v = Arrays.copyOf(v, upTo);
+                }
+
+                return BigIntegerPoint.newSetQuery(field, v);
+            }
+
+            @Override
+            public Query rangeQuery(
+                String field,
+                Object lowerTerm,
+                Object upperTerm,
+                boolean includeLower,
+                boolean includeUpper,
+                boolean hasDocValues,
+                QueryShardContext context
+            ) {
+                return unsignedLongRangeQuery(lowerTerm, upperTerm, includeLower, includeUpper, (l, u) -> {
+                    Query query = BigIntegerPoint.newRangeQuery(field, l, u);
+                    if (hasDocValues) {
+                        Query dvQuery = SortedUnsignedLongDocValuesRangeQuery.newSlowRangeQuery(field, l, u);
+                        query = new IndexOrDocValuesQuery(query, dvQuery);
+                    }
+                    return query;
+                });
+            }
+
+            @Override
+            public List<Field> createFields(String name, Number value, boolean indexed, boolean docValued, boolean stored) {
+                List<Field> fields = new ArrayList<>();
+                final BigInteger v = Numbers.toUnsignedLongExact(value);
+
+                if (indexed) {
+                    fields.add(new BigIntegerPoint(name, v));
+                }
+
+                if (docValued) {
+                    fields.add(new SortedNumericDocValuesField(name, v.longValue()));
+                }
+
+                if (stored) {
+                    fields.add(new StoredField(name, v.toString()));
+                }
+
+                return fields;
+            }
+
+            @Override
+            Number valueForSearch(String value) {
+                return new BigInteger(value);
+            }
         };
 
         private final String name;
@@ -818,6 +963,8 @@ public abstract Query rangeQuery(
 
         public abstract List<Field> createFields(String name, Number value, boolean indexed, boolean docValued, boolean stored);
 
+        abstract Number valueForSearch(String value);
+
         Number valueForSearch(Number value) {
             return value;
         }
@@ -894,6 +1041,28 @@ public static long objectToLong(Object value, boolean coerce) {
             return Numbers.toLong(stringValue, coerce);
         }
 
+        /**
+         * Converts and Object to a {@code long} by checking it against known
+         * types and checking its range.
+         */
+        public static BigInteger objectToUnsignedLong(Object value, boolean coerce) {
+            if (value instanceof Long) {
+                return Numbers.toUnsignedBigInteger(((Long) value).longValue());
+            }
+
+            double doubleValue = objectToDouble(value);
+            if (doubleValue < Numbers.MIN_UNSIGNED_LONG_VALUE.doubleValue()
+                || doubleValue > Numbers.MAX_UNSIGNED_LONG_VALUE.doubleValue()) {
+                throw new IllegalArgumentException("Value [" + value + "] is out of range for an unsigned long");
+            }
+            if (!coerce && doubleValue % 1 != 0) {
+                throw new IllegalArgumentException("Value [" + value + "] has a decimal part");
+            }
+
+            String stringValue = (value instanceof BytesRef) ? ((BytesRef) value).utf8ToString() : value.toString();
+            return Numbers.toUnsignedLong(stringValue, coerce);
+        }
+
         public static Query doubleRangeQuery(
             Object lowerTerm,
             Object upperTerm,
@@ -958,8 +1127,54 @@ public static Query longRangeQuery(
             }
             return builder.apply(l, u);
         }
+
+        /**
+         * Processes query bounds into {@code long}s and delegates the
+         * provided {@code builder} to build a range query.
+         */
+        public static Query unsignedLongRangeQuery(
+            Object lowerTerm,
+            Object upperTerm,
+            boolean includeLower,
+            boolean includeUpper,
+            BiFunction<BigInteger, BigInteger, Query> builder
+        ) {
+            BigInteger l = Numbers.MIN_UNSIGNED_LONG_VALUE;
+            BigInteger u = Numbers.MAX_UNSIGNED_LONG_VALUE;
+            if (lowerTerm != null) {
+                l = objectToUnsignedLong(lowerTerm, true);
+                // if the lower bound is decimal:
+                // - if the bound is positive then we increment it:
+                // if lowerTerm=1.5 then the (inclusive) bound becomes 2
+                // - if the bound is negative then we leave it as is:
+                // if lowerTerm=-1.5 then the (inclusive) bound becomes -1 due to the call to longValue
+                boolean lowerTermHasDecimalPart = hasDecimalPart(lowerTerm);
+                if ((lowerTermHasDecimalPart == false && includeLower == false) || (lowerTermHasDecimalPart && signum(lowerTerm) > 0)) {
+                    if (l.compareTo(Numbers.MAX_UNSIGNED_LONG_VALUE) == 0) {
+                        return new MatchNoDocsQuery();
+                    }
+                    l = l.add(BigInteger.ONE);
+                }
+            }
+            if (upperTerm != null) {
+                u = objectToUnsignedLong(upperTerm, true);
+                boolean upperTermHasDecimalPart = hasDecimalPart(upperTerm);
+                if ((upperTermHasDecimalPart == false && includeUpper == false) || (upperTermHasDecimalPart && signum(upperTerm) < 0)) {
+                    if (u.compareTo(Numbers.MAX_UNSIGNED_LONG_VALUE) == 0) {
+                        return new MatchNoDocsQuery();
+                    }
+                    u = u.subtract(BigInteger.ONE);
+                }
+            }
+            return builder.apply(l, u);
+        }
     }
 
+    /**
+     * Field type for numeric fields
+     *
+     * @opensearch.internal
+     */
     public static class NumberFieldType extends SimpleMappedFieldType {
 
         private final NumberType type;
@@ -1058,7 +1273,11 @@ public Object valueForDisplay(Object value) {
             if (value == null) {
                 return null;
             }
-            return type.valueForSearch((Number) value);
+            if (value instanceof String) {
+                return type.valueForSearch((String) value);
+            } else {
+                return type.valueForSearch((Number) value);
+            }
         }
 
         @Override
@@ -1086,7 +1305,11 @@ public DocValueFormat docValueFormat(String format, ZoneId timeZone) {
                 );
             }
             if (format == null) {
-                return DocValueFormat.RAW;
+                if (type == NumberType.UNSIGNED_LONG) {
+                    return DocValueFormat.UNSIGNED_LONG;
+                } else {
+                    return DocValueFormat.RAW;
+                }
             } else {
                 return new DocValueFormat.Decimal(format);
             }
diff --git a/server/src/main/java/org/opensearch/index/mapper/ObjectMapper.java b/server/src/main/java/org/opensearch/index/mapper/ObjectMapper.java
index a9923d7c6d756..1731d80585d43 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ObjectMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ObjectMapper.java
@@ -32,19 +32,18 @@
 
 package org.opensearch.index.mapper;
 
-import org.apache.lucene.index.Term;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchParseException;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.CopyOnWriteHashMap;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 
 import java.io.IOException;
@@ -58,24 +57,44 @@
 import java.util.Locale;
 import java.util.Map;
 
+/**
+ * Field mapper for object field types
+ *
+ * @opensearch.internal
+ */
 public class ObjectMapper extends Mapper implements Cloneable {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(ObjectMapper.class);
 
     public static final String CONTENT_TYPE = "object";
     public static final String NESTED_CONTENT_TYPE = "nested";
 
+    /**
+     * Parameter defaults
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final boolean ENABLED = true;
         public static final Nested NESTED = Nested.NO;
         public static final Dynamic DYNAMIC = null; // not set, inherited from root
     }
 
+    /**
+     * Dynamic field mapping specification
+     *
+     * @opensearch.internal
+     */
     public enum Dynamic {
         TRUE,
         FALSE,
         STRICT
     }
 
+    /**
+     * Nested objects
+     *
+     * @opensearch.internal
+     */
     public static class Nested {
 
         public static final Nested NO = new Nested(false, new Explicit<>(false, false), new Explicit<>(false, false));
@@ -147,6 +166,11 @@ public void setIncludeInRoot(boolean value) {
         }
     }
 
+    /**
+     * Builder for object field mapper
+     *
+     * @opensearch.internal
+     */
     @SuppressWarnings("rawtypes")
     public static class Builder<T extends Builder> extends Mapper.Builder<T> {
 
@@ -224,6 +248,11 @@ protected ObjectMapper createMapper(
         }
     }
 
+    /**
+     * Type parser for object field mapper
+     *
+     * @opensearch.internal
+     */
     public static class TypeParser implements Mapper.TypeParser {
         @Override
         public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
@@ -352,6 +381,10 @@ protected static void parseProperties(ObjectMapper.Builder objBuilder, Map<Strin
                         throw new MapperParsingException("No handler for type [" + type + "] declared on field [" + fieldName + "]");
                     }
                     String[] fieldNameParts = fieldName.split("\\.");
+                    // field name is just ".", which is invalid
+                    if (fieldNameParts.length < 1) {
+                        throw new MapperParsingException("Invalid field name " + fieldName);
+                    }
                     String realFieldName = fieldNameParts[fieldNameParts.length - 1];
                     Mapper.Builder<?> fieldBuilder = typeParser.parse(realFieldName, propNode, parserContext);
                     for (int i = fieldNameParts.length - 2; i >= 0; --i) {
@@ -388,8 +421,7 @@ protected static void parseProperties(ObjectMapper.Builder objBuilder, Map<Strin
 
     private final Nested nested;
 
-    private final String nestedTypePathAsString;
-    private final BytesRef nestedTypePathAsBytes;
+    private final String nestedTypePath;
 
     private final Query nestedTypeFilter;
 
@@ -420,9 +452,13 @@ protected static void parseProperties(ObjectMapper.Builder objBuilder, Map<Strin
         } else {
             this.mappers = CopyOnWriteHashMap.copyOf(mappers);
         }
-        this.nestedTypePathAsString = "__" + fullPath;
-        this.nestedTypePathAsBytes = new BytesRef(nestedTypePathAsString);
-        this.nestedTypeFilter = new TermQuery(new Term(TypeFieldMapper.NAME, nestedTypePathAsBytes));
+        Version version = IndexMetadata.indexCreated(settings);
+        if (version.before(Version.V_2_0_0)) {
+            this.nestedTypePath = "__" + fullPath;
+        } else {
+            this.nestedTypePath = fullPath;
+        }
+        this.nestedTypeFilter = NestedPathFieldMapper.filter(version, nestedTypePath);
     }
 
     @Override
@@ -486,8 +522,8 @@ public String fullPath() {
         return this.fullPath;
     }
 
-    public String nestedTypePathAsString() {
-        return nestedTypePathAsString;
+    public String nestedTypePath() {
+        return nestedTypePath;
     }
 
     public final Dynamic dynamic() {
diff --git a/server/src/main/java/org/opensearch/index/mapper/ParametrizedFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/ParametrizedFieldMapper.java
index 6e0b2613cf4ff..fd57975831e88 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ParametrizedFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ParametrizedFieldMapper.java
@@ -38,8 +38,8 @@
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.mapper.Mapper.TypeParser.ParserContext;
 
@@ -70,6 +70,8 @@
  *
  * Subclasses should implement a {@link Builder} that is returned from the
  * {@link #getMergeBuilder()} method, initialised with the existing builder.
+ *
+ * @opensearch.internal
  */
 public abstract class ParametrizedFieldMapper extends FieldMapper {
 
@@ -171,6 +173,8 @@ protected interface SerializerCheck<T> {
     /**
      * A configurable parameter for a field mapper
      * @param <T> the type of the value the parameter holds
+     *
+     * @opensearch.internal
      */
     public static final class Parameter<T> implements Supplier<T> {
 
@@ -542,6 +546,11 @@ public static Parameter<Float> boostParam() {
 
     }
 
+    /**
+     * Conflicts in the field mapper
+     *
+     * @opensearch.internal
+     */
     private static final class Conflicts {
 
         private final String mapperName;
@@ -567,6 +576,8 @@ void check() {
 
     /**
      * A Builder for a ParametrizedFieldMapper
+     *
+     * @opensearch.internal
      */
     public abstract static class Builder extends Mapper.Builder<Builder> {
 
@@ -694,7 +705,7 @@ public final void parse(String name, ParserContext parserContext, Map<String, Ob
                 if (Objects.equals("boost", propName)) {
                     deprecationLogger.deprecate(
                         "boost_" + name,
-                        "Parameter [boost] on field [{}] is deprecated and will be removed in 8.0",
+                        "Parameter [boost] on field [{}] is deprecated and will be removed in 3.0",
                         name
                     );
                 }
@@ -723,6 +734,8 @@ private static boolean isDeprecatedParameter(String propName, Version indexCreat
 
     /**
      * TypeParser implementation that automatically handles parsing
+     *
+     * @opensearch.internal
      */
     public static final class TypeParser implements Mapper.TypeParser {
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/ParseContext.java b/server/src/main/java/org/opensearch/index/mapper/ParseContext.java
index 50295626393ad..b4aab0323dca9 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ParseContext.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ParseContext.java
@@ -32,33 +32,43 @@
 
 package org.opensearch.index.mapper;
 
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.ObjectObjectMap;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
+/**
+ * Holds the context at parse time
+ *
+ * @opensearch.internal
+ */
 public abstract class ParseContext implements Iterable<ParseContext.Document> {
 
-    /** Fork of {@link org.apache.lucene.document.Document} with additional functionality. */
+    /**
+     * Fork of {@link org.apache.lucene.document.Document} with additional functionality.
+     *
+     * @opensearch.internal
+     */
     public static class Document implements Iterable<IndexableField> {
 
         private final Document parent;
         private final String path;
         private final String prefix;
         private final List<IndexableField> fields;
-        private ObjectObjectMap<Object, IndexableField> keyedFields;
+        private Map<Object, IndexableField> keyedFields;
 
         private Document(String path, Document parent) {
             fields = new ArrayList<>();
@@ -114,7 +124,7 @@ public void add(IndexableField field) {
         /** Add fields so that they can later be fetched using {@link #getByKey(Object)}. */
         public void addWithKey(Object key, IndexableField field) {
             if (keyedFields == null) {
-                keyedFields = new ObjectObjectHashMap<>();
+                keyedFields = new HashMap<>();
             } else if (keyedFields.containsKey(key)) {
                 throw new IllegalStateException("Only one field can be stored per key");
             }
@@ -166,6 +176,11 @@ public BytesRef getBinaryValue(String name) {
 
     }
 
+    /**
+     * Filter parse context.
+     *
+     * @opensearch.internal
+     */
     private static class FilterParseContext extends ParseContext {
 
         private final ParseContext in;
@@ -298,8 +313,43 @@ public void addIgnoredField(String field) {
         public Collection<String> getIgnoredFields() {
             return in.getIgnoredFields();
         }
+
+        @Override
+        public void incrementFieldCurrentDepth() {
+            in.incrementFieldCurrentDepth();
+        }
+
+        @Override
+        public void decrementFieldCurrentDepth() {
+            in.decrementFieldCurrentDepth();
+        }
+
+        @Override
+        public void checkFieldDepthLimit() {
+            in.checkFieldDepthLimit();
+        }
+
+        @Override
+        public void incrementFieldArrayDepth() {
+            in.incrementFieldArrayDepth();
+        }
+
+        @Override
+        public void decrementFieldArrayDepth() {
+            in.decrementFieldArrayDepth();
+        }
+
+        @Override
+        public void checkFieldArrayDepthLimit() {
+            in.checkFieldArrayDepthLimit();
+        }
     }
 
+    /**
+     * An internal parse context
+     *
+     * @opensearch.internal
+     */
     public static class InternalParseContext extends ParseContext {
 
         private final DocumentMapper docMapper;
@@ -326,6 +376,14 @@ public static class InternalParseContext extends ParseContext {
 
         private long numNestedDocs;
 
+        private long currentFieldDepth;
+
+        private final long maxAllowedFieldDepth;
+
+        private long currentArrayDepth;
+
+        private final long maxAllowedArrayDepth;
+
         private final List<Mapper> dynamicMappers;
 
         private boolean docsReversed = false;
@@ -352,6 +410,10 @@ public InternalParseContext(
             this.dynamicMappers = new ArrayList<>();
             this.maxAllowedNumNestedDocs = indexSettings.getMappingNestedDocsLimit();
             this.numNestedDocs = 0L;
+            this.currentFieldDepth = 0L;
+            this.currentArrayDepth = 0L;
+            this.maxAllowedFieldDepth = indexSettings.getMappingDepthLimit();
+            this.maxAllowedArrayDepth = indexSettings.getMappingDepthLimit();
         }
 
         @Override
@@ -503,6 +565,60 @@ public void addIgnoredField(String field) {
         public Collection<String> getIgnoredFields() {
             return Collections.unmodifiableCollection(ignoredFields);
         }
+
+        @Override
+        public void incrementFieldCurrentDepth() {
+            this.currentFieldDepth++;
+        }
+
+        @Override
+        public void decrementFieldCurrentDepth() {
+            if (this.currentFieldDepth > 0) {
+                this.currentFieldDepth--;
+            }
+        }
+
+        @Override
+        public void checkFieldDepthLimit() {
+            if (this.currentFieldDepth > maxAllowedFieldDepth) {
+                this.currentFieldDepth = 0;
+                throw new OpenSearchParseException(
+                    "The depth of the field has exceeded the allowed limit of ["
+                        + maxAllowedFieldDepth
+                        + "]."
+                        + " This limit can be set by changing the ["
+                        + MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING.getKey()
+                        + "] index level setting."
+                );
+            }
+        }
+
+        @Override
+        public void incrementFieldArrayDepth() {
+            this.currentArrayDepth++;
+        }
+
+        @Override
+        public void decrementFieldArrayDepth() {
+            if (this.currentArrayDepth > 0) {
+                this.currentArrayDepth--;
+            }
+        }
+
+        @Override
+        public void checkFieldArrayDepthLimit() {
+            if (this.currentArrayDepth > maxAllowedArrayDepth) {
+                this.currentArrayDepth = 0;
+                throw new OpenSearchParseException(
+                    "The depth of the nested array field has exceeded the allowed limit of ["
+                        + maxAllowedArrayDepth
+                        + "]."
+                        + " This limit can be set by changing the ["
+                        + MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING.getKey()
+                        + "] index level setting."
+                );
+            }
+        }
     }
 
     /**
@@ -668,4 +784,17 @@ public final <T> T parseExternalValue(Class<T> clazz) {
      * Get dynamic mappers created while parsing.
      */
     public abstract List<Mapper> getDynamicMappers();
+
+    public abstract void incrementFieldCurrentDepth();
+
+    public abstract void decrementFieldCurrentDepth();
+
+    public abstract void checkFieldDepthLimit();
+
+    public abstract void incrementFieldArrayDepth();
+
+    public abstract void decrementFieldArrayDepth();
+
+    public abstract void checkFieldArrayDepthLimit();
+
 }
diff --git a/server/src/main/java/org/opensearch/index/mapper/ParsedDocument.java b/server/src/main/java/org/opensearch/index/mapper/ParsedDocument.java
index 6991db3306ea7..378781151d610 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ParsedDocument.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ParsedDocument.java
@@ -33,15 +33,18 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.document.Field;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.mapper.ParseContext.Document;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.index.mapper.MapperService.MergeReason;
+import org.opensearch.index.mapper.ParseContext.Document;
 
 import java.util.List;
 
 /**
  * The result of parsing a document.
+ *
+ * @opensearch.internal
  */
 public class ParsedDocument {
 
@@ -55,7 +58,7 @@ public class ParsedDocument {
     private final List<Document> documents;
 
     private BytesReference source;
-    private XContentType xContentType;
+    private MediaType mediaType;
 
     private Mapping dynamicMappingsUpdate;
 
@@ -66,7 +69,7 @@ public ParsedDocument(
         String routing,
         List<Document> documents,
         BytesReference source,
-        XContentType xContentType,
+        MediaType mediaType,
         Mapping dynamicMappingsUpdate
     ) {
         this.version = version;
@@ -76,7 +79,7 @@ public ParsedDocument(
         this.documents = documents;
         this.source = source;
         this.dynamicMappingsUpdate = dynamicMappingsUpdate;
-        this.xContentType = xContentType;
+        this.mediaType = mediaType;
     }
 
     public String id() {
@@ -120,13 +123,13 @@ public BytesReference source() {
         return this.source;
     }
 
-    public XContentType getXContentType() {
-        return this.xContentType;
+    public MediaType getMediaType() {
+        return this.mediaType;
     }
 
     public void setSource(BytesReference source, XContentType xContentType) {
         this.source = source;
-        this.xContentType = xContentType;
+        this.mediaType = xContentType;
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/index/mapper/RangeFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/RangeFieldMapper.java
index 2568009cfc0d5..3723e469d3049 100644
--- a/server/src/main/java/org/opensearch/index/mapper/RangeFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/RangeFieldMapper.java
@@ -32,11 +32,14 @@
 
 package org.opensearch.index.mapper;
 
+import org.apache.lucene.document.InvertableType;
+import org.apache.lucene.document.StoredValue;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.geo.ShapeRelation;
@@ -48,7 +51,7 @@
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.util.LocaleUtils;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.plain.BinaryIndexFieldData;
 import org.opensearch.index.query.QueryShardContext;
@@ -77,11 +80,20 @@
 import static org.opensearch.index.query.RangeQueryBuilder.LTE_FIELD;
 import static org.opensearch.index.query.RangeQueryBuilder.LT_FIELD;
 
-/** A {@link FieldMapper} for indexing numeric and date ranges, and creating queries */
+/**
+ * A {@link FieldMapper} for indexing numeric and date ranges, and creating queries
+ *
+ * @opensearch.internal
+ */
 public class RangeFieldMapper extends ParametrizedFieldMapper {
     public static final boolean DEFAULT_INCLUDE_UPPER = true;
     public static final boolean DEFAULT_INCLUDE_LOWER = true;
 
+    /**
+     * Default parameters for range fields
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final Explicit<Boolean> COERCE = new Explicit<>(true, false);
         public static final DateFormatter DATE_FORMATTER = DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER;
@@ -94,6 +106,11 @@ private static RangeFieldMapper toType(FieldMapper in) {
         return (RangeFieldMapper) in;
     }
 
+    /**
+     * Builder for range fields
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Parameter<Boolean> index = Parameter.indexParam(m -> toType(m).index, true);
@@ -127,7 +144,7 @@ public Builder(String name, RangeType type, Settings settings) {
                 type,
                 COERCE_SETTING.get(settings),
                 IGNORE_MALFORMED_SETTING.get(settings),
-                hasIndexCreated(settings) ? Version.indexCreated(settings) : null
+                hasIndexCreated(settings) ? IndexMetadata.indexCreated(settings) : null
             );
         }
 
@@ -229,6 +246,11 @@ public RangeFieldMapper build(BuilderContext context) {
         }
     }
 
+    /**
+     * Field type for range fields
+     *
+     * @opensearch.internal
+     */
     public static final class RangeFieldType extends MappedFieldType {
         protected final RangeType rangeType;
         protected final DateFormatter dateTimeFormatter;
@@ -555,7 +577,11 @@ private static Range parseIpRangeFromCidr(final XContentParser parser) throws IO
         }
     }
 
-    /** Class defining a range */
+    /**
+     * Class defining a range
+     *
+     * @opensearch.internal
+     */
     public static class Range {
         RangeType type;
         Object from;
@@ -614,6 +640,11 @@ public Object getTo() {
         }
     }
 
+    /**
+     * Doc values field for binary ranges
+     *
+     * @opensearch.internal
+     */
     static class BinaryRangesDocValuesField extends CustomDocValuesField {
 
         private final Set<Range> ranges;
@@ -638,5 +669,15 @@ public BytesRef binaryValue() {
                 throw new OpenSearchException("failed to encode ranges", e);
             }
         }
+
+        @Override
+        public StoredValue storedValue() {
+            return null;
+        }
+
+        @Override
+        public InvertableType invertableType() {
+            return InvertableType.BINARY;
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/mapper/RangeType.java b/server/src/main/java/org/opensearch/index/mapper/RangeType.java
index 5f666dece7ed2..c8cd317779c7c 100644
--- a/server/src/main/java/org/opensearch/index/mapper/RangeType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/RangeType.java
@@ -51,7 +51,7 @@
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateMathParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 
 import java.io.IOException;
@@ -66,7 +66,11 @@
 import java.util.Set;
 import java.util.function.BiFunction;
 
-/** Enum defining the type of range */
+/**
+ * Enum defining the type of range
+ *
+ * @opensearch.internal
+ */
 public enum RangeType {
     IP("ip_range", LengthType.FIXED_16) {
         @Override
@@ -978,6 +982,11 @@ public final Mapper.TypeParser parser() {
     private final NumberFieldMapper.NumberType numberType;
     public final LengthType lengthType;
 
+    /**
+     * Type of length
+     *
+     * @opensearch.internal
+     */
     public enum LengthType {
         FIXED_4 {
             @Override
diff --git a/server/src/main/java/org/opensearch/index/mapper/RootObjectMapper.java b/server/src/main/java/org/opensearch/index/mapper/RootObjectMapper.java
index b83ce6022b012..f9a7d7c72565e 100644
--- a/server/src/main/java/org/opensearch/index/mapper/RootObjectMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/RootObjectMapper.java
@@ -35,12 +35,13 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Explicit;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DynamicTemplate.XContentFieldType;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 
@@ -57,9 +58,19 @@
 import static org.opensearch.common.xcontent.support.XContentMapValues.nodeBooleanValue;
 import static org.opensearch.index.mapper.TypeParsers.parseDateTimeFormatter;
 
+/**
+ * The root object mapper for a document
+ *
+ * @opensearch.internal
+ */
 public class RootObjectMapper extends ObjectMapper {
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(RootObjectMapper.class);
 
+    /**
+     * Default parameters for root object
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final DateFormatter[] DYNAMIC_DATE_TIME_FORMATTERS = new DateFormatter[] {
             DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER,
@@ -68,6 +79,11 @@ public static class Defaults {
         public static final boolean NUMERIC_DETECTION = false;
     }
 
+    /**
+     * Builder for the root object
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ObjectMapper.Builder<Builder> {
 
         protected Explicit<DynamicTemplate[]> dynamicTemplates = new Explicit<>(new DynamicTemplate[0], false);
@@ -148,6 +164,11 @@ private static void fixRedundantIncludes(ObjectMapper objectMapper, boolean pare
         }
     }
 
+    /**
+     * Type parser for the root object
+     *
+     * @opensearch.internal
+     */
     public static class TypeParser extends ObjectMapper.TypeParser {
 
         @Override
@@ -440,7 +461,7 @@ private static void validateDynamicTemplate(Mapper.TypeParser.ParserContext pars
                 Locale.ROOT,
                 "dynamic template [%s] has invalid content [%s]",
                 dynamicTemplate.getName(),
-                Strings.toString(dynamicTemplate)
+                Strings.toString(MediaTypeRegistry.JSON, dynamicTemplate)
             );
 
             final String deprecationMessage;
diff --git a/server/src/main/java/org/opensearch/index/mapper/RoutingFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/RoutingFieldMapper.java
index e487673b5c9da..222ba70a5ce0c 100644
--- a/server/src/main/java/org/opensearch/index/mapper/RoutingFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/RoutingFieldMapper.java
@@ -42,6 +42,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Internal field mapper for _routing fields
+ *
+ * @opensearch.internal
+ */
 public class RoutingFieldMapper extends MetadataFieldMapper {
 
     public static final String NAME = "_routing";
@@ -52,6 +57,11 @@ public ParametrizedFieldMapper.Builder getMergeBuilder() {
         return new Builder().init(this);
     }
 
+    /**
+     * Default parameters for routing fields
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
 
         public static final FieldType FIELD_TYPE = new FieldType();
@@ -70,6 +80,11 @@ private static RoutingFieldMapper toType(FieldMapper in) {
         return (RoutingFieldMapper) in;
     }
 
+    /**
+     * Builder for routing fields
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends MetadataFieldMapper.Builder {
 
         final Parameter<Boolean> required = Parameter.boolParam("required", false, m -> toType(m).required, Defaults.REQUIRED);
@@ -91,6 +106,11 @@ public RoutingFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new ConfigurableTypeParser(c -> new RoutingFieldMapper(Defaults.REQUIRED), c -> new Builder());
 
+    /**
+     * Field type for routing fields
+     *
+     * @opensearch.internal
+     */
     static final class RoutingFieldType extends StringFieldType {
 
         static RoutingFieldType INSTANCE = new RoutingFieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/SeqNoFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/SeqNoFieldMapper.java
index 490e1a31ae72b..16f76f087e403 100644
--- a/server/src/main/java/org/opensearch/index/mapper/SeqNoFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/SeqNoFieldMapper.java
@@ -65,13 +65,16 @@
  * identical seq# values for two document copies. The primary term is stored as
  * a doc value field without being indexed, since it is only intended for use
  * as a key-value lookup.
-
+ *
+ * @opensearch.internal
  */
 public class SeqNoFieldMapper extends MetadataFieldMapper {
 
     /**
      * A sequence ID, which is made up of a sequence number (both the searchable
      * and doc_value version of the field) and the primary term.
+     *
+     * @opensearch.internal
      */
     public static class SequenceIDFields {
 
@@ -107,6 +110,11 @@ public static SequenceIDFields emptySeqID() {
 
     public static final TypeParser PARSER = new FixedTypeParser(c -> new SeqNoFieldMapper());
 
+    /**
+     * Field type for internal sequence numbers
+     *
+     * @opensearch.internal
+     */
     static final class SeqNoFieldType extends SimpleMappedFieldType {
 
         private static final SeqNoFieldType INSTANCE = new SeqNoFieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/SimpleMappedFieldType.java b/server/src/main/java/org/opensearch/index/mapper/SimpleMappedFieldType.java
index 44c89211f5ef0..7ea5d49e234a5 100644
--- a/server/src/main/java/org/opensearch/index/mapper/SimpleMappedFieldType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/SimpleMappedFieldType.java
@@ -42,6 +42,8 @@
 
 /**
  * {@link MappedFieldType} base impl for field types that are neither dates nor ranges.
+ *
+ * @opensearch.internal
  */
 public abstract class SimpleMappedFieldType extends MappedFieldType {
 
diff --git a/server/src/main/java/org/opensearch/index/mapper/SourceFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/SourceFieldMapper.java
index 8791c23e49051..c13a0b5cec62c 100644
--- a/server/src/main/java/org/opensearch/index/mapper/SourceFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/SourceFieldMapper.java
@@ -39,16 +39,16 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.search.lookup.SearchLookup;
@@ -60,6 +60,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Internal field mapper for storing source (and recovery source)
+ *
+ * @opensearch.internal
+ */
 public class SourceFieldMapper extends MetadataFieldMapper {
 
     public static final String NAME = "_source";
@@ -68,6 +73,11 @@ public class SourceFieldMapper extends MetadataFieldMapper {
     public static final String CONTENT_TYPE = "_source";
     private final Function<Map<String, ?>, Map<String, Object>> filter;
 
+    /**
+     * Default parameters for source fields
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final String NAME = SourceFieldMapper.NAME;
         public static final boolean ENABLED = true;
@@ -86,6 +96,11 @@ private static SourceFieldMapper toType(FieldMapper in) {
         return (SourceFieldMapper) in;
     }
 
+    /**
+     * Builder for source fields
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends MetadataFieldMapper.Builder {
 
         private final Parameter<Boolean> enabled = Parameter.boolParam("enabled", false, m -> toType(m).enabled, Defaults.ENABLED);
@@ -123,6 +138,11 @@ public SourceFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new ConfigurableTypeParser(c -> new SourceFieldMapper(), c -> new Builder());
 
+    /**
+     * Field type for source field mapper
+     *
+     * @opensearch.internal
+     */
     static final class SourceFieldType extends MappedFieldType {
 
         private SourceFieldType(boolean enabled) {
@@ -182,7 +202,7 @@ public boolean isComplete() {
     @Override
     public void preParse(ParseContext context) throws IOException {
         BytesReference originalSource = context.sourceToParse().source();
-        XContentType contentType = context.sourceToParse().getXContentType();
+        MediaType contentType = context.sourceToParse().getMediaType();
         final BytesReference adaptedSource = applyFilters(originalSource, contentType);
 
         if (adaptedSource != null) {
@@ -199,16 +219,16 @@ public void preParse(ParseContext context) throws IOException {
     }
 
     @Nullable
-    public BytesReference applyFilters(@Nullable BytesReference originalSource, @Nullable XContentType contentType) throws IOException {
+    public BytesReference applyFilters(@Nullable BytesReference originalSource, @Nullable MediaType contentType) throws IOException {
         if (enabled && originalSource != null) {
             // Percolate and tv APIs may not set the source and that is ok, because these APIs will not index any data
             if (filter != null) {
                 // we don't update the context source if we filter, we want to keep it as is...
-                Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(originalSource, true, contentType);
+                Tuple<? extends MediaType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(originalSource, true, contentType);
                 Map<String, Object> filteredSource = filter.apply(mapTuple.v2());
                 BytesStreamOutput bStream = new BytesStreamOutput();
-                XContentType actualContentType = mapTuple.v1();
-                XContentBuilder builder = XContentFactory.contentBuilder(actualContentType, bStream).map(filteredSource);
+                MediaType actualContentType = mapTuple.v1();
+                XContentBuilder builder = MediaTypeRegistry.contentBuilder(actualContentType, bStream).map(filteredSource);
                 builder.close();
                 return bStream.bytes();
             } else {
diff --git a/server/src/main/java/org/opensearch/index/mapper/SourceToParse.java b/server/src/main/java/org/opensearch/index/mapper/SourceToParse.java
index 4aa8d3117bc9c..adacd6c450f7a 100644
--- a/server/src/main/java/org/opensearch/index/mapper/SourceToParse.java
+++ b/server/src/main/java/org/opensearch/index/mapper/SourceToParse.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.index.mapper;
 
-import java.util.Objects;
-
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+
+import java.util.Objects;
 
+/**
+ * Stores the document source
+ *
+ * @opensearch.internal
+ */
 public class SourceToParse {
 
     private final BytesReference source;
@@ -49,20 +54,20 @@ public class SourceToParse {
 
     private final @Nullable String routing;
 
-    private final XContentType xContentType;
+    private final MediaType mediaType;
 
-    public SourceToParse(String index, String id, BytesReference source, XContentType xContentType, @Nullable String routing) {
+    public SourceToParse(String index, String id, BytesReference source, MediaType mediaType, @Nullable String routing) {
         this.index = Objects.requireNonNull(index);
         this.id = Objects.requireNonNull(id);
         // we always convert back to byte array, since we store it and Field only supports bytes..
         // so, we might as well do it here, and improve the performance of working with direct byte arrays
         this.source = new BytesArray(Objects.requireNonNull(source).toBytesRef());
-        this.xContentType = Objects.requireNonNull(xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
         this.routing = routing;
     }
 
-    public SourceToParse(String index, String id, BytesReference source, XContentType xContentType) {
-        this(index, id, source, xContentType, null);
+    public SourceToParse(String index, String id, BytesReference source, MediaType mediaType) {
+        this(index, id, source, mediaType, null);
     }
 
     public BytesReference source() {
@@ -81,10 +86,15 @@ public String id() {
         return this.routing;
     }
 
-    public XContentType getXContentType() {
-        return this.xContentType;
+    public MediaType getMediaType() {
+        return this.mediaType;
     }
 
+    /**
+     * Origin of the source
+     *
+     * @opensearch.internal
+     */
     public enum Origin {
         PRIMARY,
         REPLICA
diff --git a/server/src/main/java/org/opensearch/index/mapper/SourceValueFetcher.java b/server/src/main/java/org/opensearch/index/mapper/SourceValueFetcher.java
index 9467f22afa8e8..69f53ba126790 100644
--- a/server/src/main/java/org/opensearch/index/mapper/SourceValueFetcher.java
+++ b/server/src/main/java/org/opensearch/index/mapper/SourceValueFetcher.java
@@ -48,6 +48,8 @@
  * to implement value fetching.
  *
  * Field types that handle arrays directly should instead use {@link ArraySourceValueFetcher}.
+ *
+ * @opensearch.internal
  */
 public abstract class SourceValueFetcher implements ValueFetcher {
     private final Set<String> sourcePaths;
@@ -73,7 +75,7 @@ public List<Object> fetchValues(SourceLookup lookup) {
         for (String path : sourcePaths) {
             Object sourceValue = lookup.extractValue(path, nullValue);
             if (sourceValue == null) {
-                return org.opensearch.common.collect.List.of();
+                return List.of();
             }
 
             // We allow source values to contain multiple levels of arrays, such as `"field": [[1, 2]]`.
diff --git a/server/src/main/java/org/opensearch/index/mapper/StrictDynamicMappingException.java b/server/src/main/java/org/opensearch/index/mapper/StrictDynamicMappingException.java
index 6e26ad46eecdc..9127641128dad 100644
--- a/server/src/main/java/org/opensearch/index/mapper/StrictDynamicMappingException.java
+++ b/server/src/main/java/org/opensearch/index/mapper/StrictDynamicMappingException.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when mapping is set to `STRICT`
+ *
+ * @opensearch.internal
+ */
 public class StrictDynamicMappingException extends MapperParsingException {
 
     public StrictDynamicMappingException(String path, String fieldName) {
diff --git a/server/src/main/java/org/opensearch/index/mapper/StringFieldType.java b/server/src/main/java/org/opensearch/index/mapper/StringFieldType.java
index 42bd52dddf520..fbfca44c3062a 100644
--- a/server/src/main/java/org/opensearch/index/mapper/StringFieldType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/StringFieldType.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.AutomatonQuery;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
@@ -44,12 +43,12 @@
 import org.apache.lucene.search.WildcardQuery;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
+import org.apache.lucene.util.automaton.Operations;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.lucene.BytesRefs;
 import org.opensearch.common.lucene.search.AutomatonQueries;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.query.support.QueryParsers;
 
 import java.util.Map;
 import java.util.regex.Matcher;
@@ -60,7 +59,10 @@
 /** Base class for {@link MappedFieldType} implementations that use the same
  * representation for internal index terms as the external representation so
  * that partial matching queries such as prefix, wildcard and fuzzy queries
- * can be implemented. */
+ * can be implemented.
+ *
+ * @opensearch.internal
+ */
 public abstract class StringFieldType extends TermBasedFieldType {
 
     private static final Pattern WILDCARD_PATTERN = Pattern.compile("(\\\\.)|([?*]+)");
@@ -111,19 +113,13 @@ public Query prefixQuery(String value, MultiTermQuery.RewriteMethod method, bool
             );
         }
         failIfNotIndexed();
-        if (caseInsensitive) {
-            AutomatonQuery query = AutomatonQueries.caseInsensitivePrefixQuery((new Term(name(), indexedValueForSearch(value))));
-            if (method != null) {
-                query.setRewriteMethod(method);
-            }
-            return query;
-
+        if (method == null) {
+            method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
         }
-        PrefixQuery query = new PrefixQuery(new Term(name(), indexedValueForSearch(value)));
-        if (method != null) {
-            query.setRewriteMethod(method);
+        if (caseInsensitive) {
+            return AutomatonQueries.caseInsensitivePrefixQuery((new Term(name(), indexedValueForSearch(value))), method);
         }
-        return query;
+        return new PrefixQuery(new Term(name(), indexedValueForSearch(value)), method);
     }
 
     public static final String normalizeWildcardPattern(String fieldname, String value, Analyzer normalizer) {
@@ -156,8 +152,34 @@ public static final String normalizeWildcardPattern(String fieldname, String val
         return sb.toBytesRef().utf8ToString();
     }
 
+    /** optionally normalize the wildcard pattern based on the value of {@code caseInsensitive} */
     @Override
     public Query wildcardQuery(String value, MultiTermQuery.RewriteMethod method, boolean caseInsensitive, QueryShardContext context) {
+        return wildcardQuery(value, method, caseInsensitive, false, context);
+    }
+
+    /** always normalizes the wildcard pattern to lowercase */
+    @Override
+    public Query normalizedWildcardQuery(String value, MultiTermQuery.RewriteMethod method, QueryShardContext context) {
+        return wildcardQuery(value, method, false, true, context);
+    }
+
+    /**
+     * return a wildcard query
+     *
+     * @param value the pattern
+     * @param method rewrite method
+     * @param caseInsensitive should ignore case; note, only used if there is no analyzer, else we use the analyzer rules
+     * @param normalizeIfAnalyzed force normalize casing if an analyzer is used
+     * @param context the query shard context
+     */
+    public Query wildcardQuery(
+        String value,
+        MultiTermQuery.RewriteMethod method,
+        boolean caseInsensitive,
+        boolean normalizeIfAnalyzed,
+        QueryShardContext context
+    ) {
         failIfNotIndexed();
         if (context.allowExpensiveQueries() == false) {
             throw new OpenSearchException(
@@ -166,20 +188,19 @@ public Query wildcardQuery(String value, MultiTermQuery.RewriteMethod method, bo
         }
 
         Term term;
-        if (getTextSearchInfo().getSearchAnalyzer() != null) {
+        if (getTextSearchInfo().getSearchAnalyzer() != null && normalizeIfAnalyzed) {
             value = normalizeWildcardPattern(name(), value, getTextSearchInfo().getSearchAnalyzer());
             term = new Term(name(), value);
         } else {
             term = new Term(name(), indexedValueForSearch(value));
         }
         if (caseInsensitive) {
-            AutomatonQuery query = AutomatonQueries.caseInsensitiveWildcardQuery(term);
-            QueryParsers.setRewriteMethod(query, method);
-            return query;
+            return AutomatonQueries.caseInsensitiveWildcardQuery(term, method);
+        }
+        if (method == null) {
+            method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
         }
-        WildcardQuery query = new WildcardQuery(term);
-        QueryParsers.setRewriteMethod(query, method);
-        return query;
+        return new WildcardQuery(term, Operations.DEFAULT_DETERMINIZE_WORK_LIMIT, method);
     }
 
     @Override
@@ -197,11 +218,17 @@ public Query regexpQuery(
             );
         }
         failIfNotIndexed();
-        RegexpQuery query = new RegexpQuery(new Term(name(), indexedValueForSearch(value)), syntaxFlags, matchFlags, maxDeterminizedStates);
-        if (method != null) {
-            query.setRewriteMethod(method);
+        if (method == null) {
+            method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
         }
-        return query;
+        return new RegexpQuery(
+            new Term(name(), indexedValueForSearch(value)),
+            syntaxFlags,
+            matchFlags,
+            RegexpQuery.DEFAULT_PROVIDER,
+            maxDeterminizedStates,
+            method
+        );
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/mapper/TermBasedFieldType.java b/server/src/main/java/org/opensearch/index/mapper/TermBasedFieldType.java
index 77efea3c20b6c..78dae2d2c27fc 100644
--- a/server/src/main/java/org/opensearch/index/mapper/TermBasedFieldType.java
+++ b/server/src/main/java/org/opensearch/index/mapper/TermBasedFieldType.java
@@ -46,7 +46,10 @@
 import java.util.Map;
 
 /** Base {@link MappedFieldType} implementation for a field that is indexed
- *  with the inverted index. */
+ *  with the inverted index.
+ *
+ * @opensearch.internal
+ */
 public abstract class TermBasedFieldType extends SimpleMappedFieldType {
 
     public TermBasedFieldType(
diff --git a/server/src/main/java/org/opensearch/index/mapper/TextFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/TextFieldMapper.java
index 049c85dc910ed..a772b363936f3 100644
--- a/server/src/main/java/org/opensearch/index/mapper/TextFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/TextFieldMapper.java
@@ -75,9 +75,9 @@
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.AutomatonQueries;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -99,16 +99,26 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.IntPredicate;
 import java.util.function.Supplier;
 
-/** A {@link FieldMapper} for full-text fields. */
+/**
+ * A {@link FieldMapper} for full-text fields.
+ *
+ * @opensearch.internal
+ */
 public class TextFieldMapper extends ParametrizedFieldMapper {
 
     public static final String CONTENT_TYPE = "text";
     private static final int POSITION_INCREMENT_GAP_USE_ANALYZER = -1;
     private static final String FAST_PHRASE_SUFFIX = "._index_phrase";
 
+    /**
+     * Default paramters for text fields
+     *
+     * @opensearch.internal
+     */
     public static class Defaults {
         public static final double FIELDDATA_MIN_FREQUENCY = 0;
         public static final double FIELDDATA_MAX_FREQUENCY = Integer.MAX_VALUE;
@@ -134,10 +144,15 @@ public static class Defaults {
         public static final int POSITION_INCREMENT_GAP = 100;
     }
 
-    private static Builder builder(FieldMapper in) {
-        return ((TextFieldMapper) in).builder;
+    private static TextFieldMapper toType(FieldMapper in) {
+        return (TextFieldMapper) in;
     }
 
+    /**
+     * Prefix configuration
+     *
+     * @opensearch.internal
+     */
     private static final class PrefixConfig implements ToXContent {
         final int minChars;
         final int maxChars;
@@ -195,6 +210,11 @@ private static PrefixConfig parsePrefixConfig(String propName, ParserContext par
         return new PrefixConfig(minChars, maxChars);
     }
 
+    /**
+     * Frequency filter for field data
+     *
+     * @opensearch.internal
+     */
     private static final class FielddataFrequencyFilter implements ToXContent {
         final double minFreq;
         final double maxFreq;
@@ -252,48 +272,65 @@ private static FielddataFrequencyFilter parseFrequencyFilter(String name, Parser
         return new FielddataFrequencyFilter(minFrequency, maxFrequency, minSegmentSize);
     }
 
+    /**
+     * Builder for text fields
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ParametrizedFieldMapper.Builder {
 
         private final Version indexCreatedVersion;
 
-        private final Parameter<Boolean> index = Parameter.indexParam(m -> builder(m).index.getValue(), true);
-        private final Parameter<Boolean> store = Parameter.storeParam(m -> builder(m).store.getValue(), false);
+        private final Parameter<Boolean> index = Parameter.indexParam(m -> toType(m).mappedFieldType.isSearchable(), true);
+        private final Parameter<Boolean> store = Parameter.storeParam(m -> toType(m).fieldType.stored(), false);
 
-        final Parameter<SimilarityProvider> similarity = TextParams.similarity(m -> builder(m).similarity.getValue());
+        final Parameter<SimilarityProvider> similarity = TextParams.similarity(m -> toType(m).similarity);
 
-        final Parameter<String> indexOptions = TextParams.indexOptions(m -> builder(m).indexOptions.getValue());
-        final Parameter<Boolean> norms = TextParams.norms(true, m -> builder(m).norms.getValue());
-        final Parameter<String> termVectors = TextParams.termVectors(m -> builder(m).termVectors.getValue());
+        final Parameter<String> indexOptions = TextParams.indexOptions(m -> toType(m).indexOptions);
+        final Parameter<Boolean> norms = TextParams.norms(true, m -> toType(m).fieldType.omitNorms() == false);
+        final Parameter<String> termVectors = TextParams.termVectors(m -> toType(m).termVectors);
 
         final Parameter<Integer> positionIncrementGap = Parameter.intParam(
             "position_increment_gap",
             false,
-            m -> builder(m).positionIncrementGap.getValue(),
+            m -> toType(m).positionIncrementGap,
             POSITION_INCREMENT_GAP_USE_ANALYZER
         );
 
-        final Parameter<Boolean> fieldData = Parameter.boolParam("fielddata", true, m -> builder(m).fieldData.getValue(), false);
+        final Parameter<Boolean> fieldData = Parameter.boolParam(
+            "fielddata",
+            true,
+            m -> ((TextFieldType) toType(m).mappedFieldType).fielddata,
+            false
+        );
         final Parameter<FielddataFrequencyFilter> freqFilter = new Parameter<>(
             "fielddata_frequency_filter",
             true,
             () -> DEFAULT_FILTER,
             TextFieldMapper::parseFrequencyFilter,
-            m -> builder(m).freqFilter.getValue()
+            m -> toType(m).freqFilter
         );
         final Parameter<Boolean> eagerGlobalOrdinals = Parameter.boolParam(
             "eager_global_ordinals",
             true,
-            m -> builder(m).eagerGlobalOrdinals.getValue(),
+            m -> toType(m).mappedFieldType.eagerGlobalOrdinals(),
             false
         );
 
-        final Parameter<Boolean> indexPhrases = Parameter.boolParam("index_phrases", false, m -> builder(m).indexPhrases.getValue(), false);
+        final Parameter<Boolean> indexPhrases = Parameter.boolParam(
+            "index_phrases",
+            false,
+            m -> ((TextFieldType) toType(m).mappedFieldType).indexPhrases,
+            false
+        );
         final Parameter<PrefixConfig> indexPrefixes = new Parameter<>(
             "index_prefixes",
             false,
             () -> null,
             TextFieldMapper::parsePrefixConfig,
-            m -> builder(m).indexPrefixes.getValue()
+            m -> Optional.ofNullable(((TextFieldType) toType(m).mappedFieldType).prefixFieldType)
+                .map(p -> new PrefixConfig(p.minChars, p.maxChars))
+                .orElse(null)
         ).acceptsNull();
 
         private final Parameter<Float> boost = Parameter.boostParam();
@@ -452,6 +489,11 @@ public TextFieldMapper build(BuilderContext context) {
 
     public static final TypeParser PARSER = new TypeParser((n, c) -> new Builder(n, c.indexVersionCreated(), c.getIndexAnalyzers()));
 
+    /**
+     * A phrase wrapped field analyzer
+     *
+     * @opensearch.internal
+     */
     private static class PhraseWrappedAnalyzer extends AnalyzerWrapper {
 
         private final Analyzer delegate;
@@ -472,6 +514,11 @@ protected TokenStreamComponents wrapComponents(String fieldName, TokenStreamComp
         }
     }
 
+    /**
+     * A prefix wrapped analyzer
+     *
+     * @opensearch.internal
+     */
     private static class PrefixWrappedAnalyzer extends AnalyzerWrapper {
 
         private final int minChars;
@@ -497,6 +544,11 @@ protected TokenStreamComponents wrapComponents(String fieldName, TokenStreamComp
         }
     }
 
+    /**
+     * Field type for phrase fields
+     *
+     * @opensearch.internal
+     */
     static final class PhraseFieldType extends StringFieldType {
 
         final TextFieldType parent;
@@ -529,6 +581,11 @@ public Query existsQuery(QueryShardContext context) {
         }
     }
 
+    /**
+     * Field type for prefix fields
+     *
+     * @opensearch.internal
+     */
     static final class PrefixFieldType extends StringFieldType {
 
         final int minChars;
@@ -582,8 +639,7 @@ public Query prefixQuery(String value, MultiTermQuery.RewriteMethod method, bool
                 automata.add(Automata.makeAnyChar());
             }
             Automaton automaton = Operations.concatenate(automata);
-            AutomatonQuery query = new AutomatonQuery(new Term(name(), value + "*"), automaton);
-            query.setRewriteMethod(method);
+            AutomatonQuery query = AutomatonQueries.createAutomatonQuery(new Term(name(), value + "*"), automaton, method);
             return new BooleanQuery.Builder().add(query, BooleanClause.Occur.SHOULD)
                 .add(new TermQuery(new Term(parentField.name(), value)), BooleanClause.Occur.SHOULD)
                 .build();
@@ -623,6 +679,11 @@ public Query existsQuery(QueryShardContext context) {
         }
     }
 
+    /**
+     * Field mapper for phrase fields
+     *
+     * @opensearch.internal
+     */
     private static final class PhraseFieldMapper extends FieldMapper {
 
         PhraseFieldMapper(FieldType fieldType, PhraseFieldType mappedFieldType) {
@@ -645,6 +706,11 @@ protected String contentType() {
         }
     }
 
+    /**
+     * Field mapper for prefix fields
+     *
+     * @opensearch.internal
+     */
     private static final class PrefixFieldMapper extends FieldMapper {
 
         protected PrefixFieldMapper(FieldType fieldType, PrefixFieldType mappedFieldType) {
@@ -676,6 +742,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Field type for text fields
+     *
+     * @opensearch.internal
+     */
     public static class TextFieldType extends StringFieldType {
 
         private boolean fielddata;
@@ -898,10 +969,16 @@ public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, S
 
     }
 
-    private final Builder builder;
     private final FieldType fieldType;
     private final PrefixFieldMapper prefixFieldMapper;
     private final PhraseFieldMapper phraseFieldMapper;
+    private final SimilarityProvider similarity;
+    private final String indexOptions;
+    private final String termVectors;
+    private final int positionIncrementGap;
+    private final Version indexCreatedVersion;
+    private final IndexAnalyzers indexAnalyzers;
+    private final FielddataFrequencyFilter freqFilter;
 
     protected TextFieldMapper(
         String simpleName,
@@ -922,7 +999,13 @@ protected TextFieldMapper(
         this.fieldType = fieldType;
         this.prefixFieldMapper = prefixFieldMapper;
         this.phraseFieldMapper = phraseFieldMapper;
-        this.builder = builder;
+        this.similarity = builder.similarity.getValue();
+        this.indexOptions = builder.indexOptions.getValue();
+        this.termVectors = builder.termVectors.getValue();
+        this.positionIncrementGap = builder.positionIncrementGap.getValue();
+        this.indexCreatedVersion = builder.indexCreatedVersion;
+        this.indexAnalyzers = builder.analyzers.indexAnalyzers;
+        this.freqFilter = builder.freqFilter.getValue();
     }
 
     @Override
@@ -932,7 +1015,7 @@ protected TextFieldMapper clone() {
 
     @Override
     public ParametrizedFieldMapper.Builder getMergeBuilder() {
-        return new Builder(simpleName(), builder.indexCreatedVersion, builder.analyzers.indexAnalyzers).init(this);
+        return new Builder(simpleName(), this.indexCreatedVersion, this.indexAnalyzers).init(this);
     }
 
     @Override
@@ -1111,24 +1194,25 @@ public static Query createPhrasePrefixQuery(
     protected void doXContentBody(XContentBuilder builder, boolean includeDefaults, Params params) throws IOException {
         // this is a pain, but we have to do this to maintain BWC
         builder.field("type", contentType());
-        this.builder.boost.toXContent(builder, includeDefaults);
-        this.builder.index.toXContent(builder, includeDefaults);
-        this.builder.store.toXContent(builder, includeDefaults);
+        Builder mapperBuilder = (TextFieldMapper.Builder) getMergeBuilder();
+        mapperBuilder.boost.toXContent(builder, includeDefaults);
+        mapperBuilder.index.toXContent(builder, includeDefaults);
+        mapperBuilder.store.toXContent(builder, includeDefaults);
         this.multiFields.toXContent(builder, params);
         this.copyTo.toXContent(builder, params);
-        this.builder.meta.toXContent(builder, includeDefaults);
-        this.builder.indexOptions.toXContent(builder, includeDefaults);
-        this.builder.termVectors.toXContent(builder, includeDefaults);
-        this.builder.norms.toXContent(builder, includeDefaults);
-        this.builder.analyzers.indexAnalyzer.toXContent(builder, includeDefaults);
-        this.builder.analyzers.searchAnalyzer.toXContent(builder, includeDefaults);
-        this.builder.analyzers.searchQuoteAnalyzer.toXContent(builder, includeDefaults);
-        this.builder.similarity.toXContent(builder, includeDefaults);
-        this.builder.eagerGlobalOrdinals.toXContent(builder, includeDefaults);
-        this.builder.positionIncrementGap.toXContent(builder, includeDefaults);
-        this.builder.fieldData.toXContent(builder, includeDefaults);
-        this.builder.freqFilter.toXContent(builder, includeDefaults);
-        this.builder.indexPrefixes.toXContent(builder, includeDefaults);
-        this.builder.indexPhrases.toXContent(builder, includeDefaults);
+        mapperBuilder.meta.toXContent(builder, includeDefaults);
+        mapperBuilder.indexOptions.toXContent(builder, includeDefaults);
+        mapperBuilder.termVectors.toXContent(builder, includeDefaults);
+        mapperBuilder.norms.toXContent(builder, includeDefaults);
+        mapperBuilder.analyzers.indexAnalyzer.toXContent(builder, includeDefaults);
+        mapperBuilder.analyzers.searchAnalyzer.toXContent(builder, includeDefaults);
+        mapperBuilder.analyzers.searchQuoteAnalyzer.toXContent(builder, includeDefaults);
+        mapperBuilder.similarity.toXContent(builder, includeDefaults);
+        mapperBuilder.eagerGlobalOrdinals.toXContent(builder, includeDefaults);
+        mapperBuilder.positionIncrementGap.toXContent(builder, includeDefaults);
+        mapperBuilder.fieldData.toXContent(builder, includeDefaults);
+        mapperBuilder.freqFilter.toXContent(builder, includeDefaults);
+        mapperBuilder.indexPrefixes.toXContent(builder, includeDefaults);
+        mapperBuilder.indexPhrases.toXContent(builder, includeDefaults);
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/mapper/TextParams.java b/server/src/main/java/org/opensearch/index/mapper/TextParams.java
index 0f764c298d912..0f46ddb021aad 100644
--- a/server/src/main/java/org/opensearch/index/mapper/TextParams.java
+++ b/server/src/main/java/org/opensearch/index/mapper/TextParams.java
@@ -47,11 +47,18 @@
 
 /**
  * Utility functions for text mapper parameters
+ *
+ * @opensearch.internal
  */
 public final class TextParams {
 
     private TextParams() {}
 
+    /**
+     * Analyzers for text
+     *
+     * @opensearch.internal
+     */
     public static final class Analyzers {
         public final Parameter<NamedAnalyzer> indexAnalyzer;
         public final Parameter<NamedAnalyzer> searchAnalyzer;
diff --git a/server/src/main/java/org/opensearch/index/mapper/TextSearchInfo.java b/server/src/main/java/org/opensearch/index/mapper/TextSearchInfo.java
index e341711621d41..535fba6c39371 100644
--- a/server/src/main/java/org/opensearch/index/mapper/TextSearchInfo.java
+++ b/server/src/main/java/org/opensearch/index/mapper/TextSearchInfo.java
@@ -40,6 +40,8 @@
 
 /**
  * Encapsulates information about how to perform text searches over a field
+ *
+ * @opensearch.internal
  */
 public class TextSearchInfo {
 
@@ -142,6 +144,8 @@ public boolean isTokenized() {
 
     /**
      * What sort of term vectors are available
+     *
+     * @opensearch.internal
      */
     public enum TermVector {
         NONE,
diff --git a/server/src/main/java/org/opensearch/index/mapper/TypeFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/TypeFieldMapper.java
deleted file mode 100644
index 9adb1430b3df0..0000000000000
--- a/server/src/main/java/org/opensearch/index/mapper/TypeFieldMapper.java
+++ /dev/null
@@ -1,200 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.mapper;
-
-import org.apache.lucene.document.Field;
-import org.apache.lucene.document.FieldType;
-import org.apache.lucene.document.SortedSetDocValuesField;
-import org.apache.lucene.index.IndexOptions;
-import org.apache.lucene.search.MatchAllDocsQuery;
-import org.apache.lucene.search.MatchNoDocsQuery;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.geo.ShapeRelation;
-import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.regex.Regex;
-import org.opensearch.common.time.DateMathParser;
-import org.opensearch.index.fielddata.IndexFieldData;
-import org.opensearch.index.fielddata.plain.ConstantIndexFieldData;
-import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.search.aggregations.support.CoreValuesSourceType;
-import org.opensearch.search.lookup.SearchLookup;
-
-import java.time.ZoneId;
-import java.util.Collections;
-import java.util.Objects;
-import java.util.function.Supplier;
-
-public class TypeFieldMapper extends MetadataFieldMapper {
-
-    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(TypeFieldType.class);
-
-    public static final String TYPES_DEPRECATION_MESSAGE = "[types removal] Using the _type field "
-        + "in queries and aggregations is deprecated, prefer to use a field instead.";
-
-    public static void emitTypesDeprecationWarning() {
-        deprecationLogger.deprecate("query_with_types", TYPES_DEPRECATION_MESSAGE);
-    }
-
-    public static final String NAME = "_type";
-
-    public static final String CONTENT_TYPE = "_type";
-
-    public static final TypeParser PARSER = new FixedTypeParser(c -> new TypeFieldMapper());
-
-    public static class Defaults {
-
-        public static final FieldType NESTED_FIELD_TYPE = new FieldType();
-
-        static {
-            NESTED_FIELD_TYPE.setIndexOptions(IndexOptions.DOCS);
-            NESTED_FIELD_TYPE.setTokenized(false);
-            NESTED_FIELD_TYPE.setStored(false);
-            NESTED_FIELD_TYPE.setOmitNorms(true);
-            NESTED_FIELD_TYPE.freeze();
-        }
-    }
-
-    public static final class TypeFieldType extends ConstantFieldType {
-
-        private final String type;
-
-        public TypeFieldType(String type) {
-            super(NAME, Collections.emptyMap());
-            this.type = type;
-        }
-
-        @Override
-        public String typeName() {
-            return CONTENT_TYPE;
-        }
-
-        @Override
-        public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
-            emitTypesDeprecationWarning();
-            return new ConstantIndexFieldData.Builder(type, name(), CoreValuesSourceType.BYTES);
-        }
-
-        @Override
-        public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup lookup, String format) {
-            throw new UnsupportedOperationException("Cannot fetch values for internal field [" + name() + "].");
-        }
-
-        @Override
-        public Query existsQuery(QueryShardContext context) {
-            emitTypesDeprecationWarning();
-            return new MatchAllDocsQuery();
-        }
-
-        @Override
-        protected boolean matches(String pattern, boolean caseInsensitive, QueryShardContext context) {
-            emitTypesDeprecationWarning();
-            if (type == null) {
-                return false;
-            }
-            return Regex.simpleMatch(pattern, type, caseInsensitive);
-        }
-
-        @Override
-        public Query rangeQuery(
-            Object lowerTerm,
-            Object upperTerm,
-            boolean includeLower,
-            boolean includeUpper,
-            ShapeRelation relation,
-            ZoneId timeZone,
-            DateMathParser parser,
-            QueryShardContext context
-        ) {
-            emitTypesDeprecationWarning();
-            BytesRef lower = (BytesRef) lowerTerm;
-            BytesRef upper = (BytesRef) upperTerm;
-            if (includeLower) {
-                if (lower.utf8ToString().compareTo(type) > 0) {
-                    return new MatchNoDocsQuery();
-                }
-            } else {
-                if (lower.utf8ToString().compareTo(type) >= 0) {
-                    return new MatchNoDocsQuery();
-                }
-            }
-            if (includeUpper) {
-                if (upper.utf8ToString().compareTo(type) < 0) {
-                    return new MatchNoDocsQuery();
-                }
-            } else {
-                if (upper.utf8ToString().compareTo(type) <= 0) {
-                    return new MatchNoDocsQuery();
-                }
-            }
-            return new MatchAllDocsQuery();
-        }
-
-        /**
-         * Build a type filter
-         *
-         * This does not emit a deprecation warning, as it is only called when a type
-         * has been specified in a REST request and warnings will have already been
-         * emitted at the REST layer.
-         */
-        public Query typeFilter(String[] types) {
-            for (String t : types) {
-                if (Objects.equals(this.type, t)) {
-                    return new MatchAllDocsQuery();
-                }
-            }
-            return new MatchNoDocsQuery();
-        }
-    }
-
-    private TypeFieldMapper() {
-        super(new TypeFieldType(null));
-    }
-
-    @Override
-    public void preParse(ParseContext context) {
-        if (fieldType.indexOptions() == IndexOptions.NONE && !fieldType.stored()) {
-            return;
-        }
-        context.doc().add(new Field(fieldType().name(), MapperService.SINGLE_MAPPING_NAME, fieldType));
-        if (fieldType().hasDocValues()) {
-            context.doc().add(new SortedSetDocValuesField(fieldType().name(), new BytesRef(MapperService.SINGLE_MAPPING_NAME)));
-        }
-    }
-
-    @Override
-    protected String contentType() {
-        return CONTENT_TYPE;
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/index/mapper/TypeParsers.java b/server/src/main/java/org/opensearch/index/mapper/TypeParsers.java
index 7f0451cc2fa84..30fcba0ae61d3 100644
--- a/server/src/main/java/org/opensearch/index/mapper/TypeParsers.java
+++ b/server/src/main/java/org/opensearch/index/mapper/TypeParsers.java
@@ -51,6 +51,11 @@
 import static org.opensearch.common.xcontent.support.XContentMapValues.nodeFloatValue;
 import static org.opensearch.common.xcontent.support.XContentMapValues.nodeStringValue;
 
+/**
+ * Foundation type parsers
+ *
+ * @opensearch.internal
+ */
 public class TypeParsers {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(TypeParsers.class);
 
@@ -150,7 +155,7 @@ public static void parseField(
                 builder.boost(nodeFloatValue(propNode));
                 deprecationLogger.deprecate(
                     "boost_" + name,
-                    "Parameter [boost] on field [{}] is deprecated and will be removed in 8.0",
+                    "Parameter [boost] on field [{}] is deprecated and will be removed in 3.0",
                     name
                 );
                 iterator.remove();
diff --git a/server/src/main/java/org/opensearch/index/mapper/Uid.java b/server/src/main/java/org/opensearch/index/mapper/Uid.java
index fa149b9dcac46..fa6094ab4ed59 100644
--- a/server/src/main/java/org/opensearch/index/mapper/Uid.java
+++ b/server/src/main/java/org/opensearch/index/mapper/Uid.java
@@ -38,6 +38,11 @@
 import java.util.Arrays;
 import java.util.Base64;
 
+/**
+ * A documents OpenSearch id
+ *
+ * @opensearch.internal
+ */
 public final class Uid {
 
     public static final char DELIMITER = '#';
diff --git a/server/src/main/java/org/opensearch/index/mapper/ValueFetcher.java b/server/src/main/java/org/opensearch/index/mapper/ValueFetcher.java
index 99d2f33701229..d1cea3fe7f1b0 100644
--- a/server/src/main/java/org/opensearch/index/mapper/ValueFetcher.java
+++ b/server/src/main/java/org/opensearch/index/mapper/ValueFetcher.java
@@ -42,6 +42,8 @@
 /**
  * A helper class for fetching field values during the {@link FetchFieldsPhase}. Each {@link MappedFieldType}
  * is in charge of defining a value fetcher through {@link MappedFieldType#valueFetcher}.
+ *
+ * @opensearch.internal
  */
 public interface ValueFetcher {
     /**
diff --git a/server/src/main/java/org/opensearch/index/mapper/VersionFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/VersionFieldMapper.java
index e601894105b59..6cef46be86a6a 100644
--- a/server/src/main/java/org/opensearch/index/mapper/VersionFieldMapper.java
+++ b/server/src/main/java/org/opensearch/index/mapper/VersionFieldMapper.java
@@ -42,7 +42,11 @@
 
 import java.util.Collections;
 
-/** Mapper for the _version field. */
+/**
+ * Mapper for the _version field.
+ *
+ * @opensearch.internal
+ */
 public class VersionFieldMapper extends MetadataFieldMapper {
 
     public static final String NAME = "_version";
@@ -50,6 +54,11 @@ public class VersionFieldMapper extends MetadataFieldMapper {
 
     public static final TypeParser PARSER = new FixedTypeParser(c -> new VersionFieldMapper());
 
+    /**
+     * Field type for internal version field
+     *
+     * @opensearch.internal
+     */
     static final class VersionFieldType extends MappedFieldType {
 
         public static final VersionFieldType INSTANCE = new VersionFieldType();
diff --git a/server/src/main/java/org/opensearch/index/mapper/package-info.java b/server/src/main/java/org/opensearch/index/mapper/package-info.java
new file mode 100644
index 0000000000000..431f5b0f4debb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/mapper/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing OpenSearch Field Mappers */
+package org.opensearch.index.mapper;
diff --git a/server/src/main/java/org/opensearch/index/merge/MergeStats.java b/server/src/main/java/org/opensearch/index/merge/MergeStats.java
index 6ef4ed77a8269..a284cec247ff1 100644
--- a/server/src/main/java/org/opensearch/index/merge/MergeStats.java
+++ b/server/src/main/java/org/opensearch/index/merge/MergeStats.java
@@ -32,16 +32,22 @@
 
 package org.opensearch.index.merge;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.Version;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stores stats about a merge process
+ *
+ * @opensearch.internal
+ */
 public class MergeStats implements Writeable, ToXContentFragment {
 
     private long total;
@@ -60,9 +66,9 @@ public class MergeStats implements Writeable, ToXContentFragment {
 
     private long totalBytesPerSecAutoThrottle;
 
-    public MergeStats() {
+    private long unreferencedFileCleanUpsPerformed;
 
-    }
+    public MergeStats() {}
 
     public MergeStats(StreamInput in) throws IOException {
         total = in.readVLong();
@@ -76,6 +82,9 @@ public MergeStats(StreamInput in) throws IOException {
         totalStoppedTimeInMillis = in.readVLong();
         totalThrottledTimeInMillis = in.readVLong();
         totalBytesPerSecAutoThrottle = in.readVLong();
+        if (in.getVersion().onOrAfter(Version.V_2_11_0)) {
+            unreferencedFileCleanUpsPerformed = in.readOptionalVLong();
+        }
     }
 
     public void add(
@@ -128,6 +137,7 @@ public void addTotals(MergeStats mergeStats) {
         this.totalSizeInBytes += mergeStats.totalSizeInBytes;
         this.totalStoppedTimeInMillis += mergeStats.totalStoppedTimeInMillis;
         this.totalThrottledTimeInMillis += mergeStats.totalThrottledTimeInMillis;
+        addUnreferencedFileCleanUpStats(mergeStats.unreferencedFileCleanUpsPerformed);
         if (this.totalBytesPerSecAutoThrottle == Long.MAX_VALUE || mergeStats.totalBytesPerSecAutoThrottle == Long.MAX_VALUE) {
             this.totalBytesPerSecAutoThrottle = Long.MAX_VALUE;
         } else {
@@ -135,6 +145,14 @@ public void addTotals(MergeStats mergeStats) {
         }
     }
 
+    public void addUnreferencedFileCleanUpStats(long unreferencedFileCleanUpsPerformed) {
+        this.unreferencedFileCleanUpsPerformed += unreferencedFileCleanUpsPerformed;
+    }
+
+    public long getUnreferencedFileCleanUpsPerformed() {
+        return this.unreferencedFileCleanUpsPerformed;
+    }
+
     /**
      * The total number of merges executed.
      */
@@ -235,10 +253,16 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field(Fields.TOTAL_THROTTLE_BYTES_PER_SEC).value(new ByteSizeValue(totalBytesPerSecAutoThrottle).toString());
         }
         builder.field(Fields.TOTAL_THROTTLE_BYTES_PER_SEC_IN_BYTES, totalBytesPerSecAutoThrottle);
+        builder.field(Fields.UNREFERENCED_FILE_CLEANUPS_PERFORMED, unreferencedFileCleanUpsPerformed);
         builder.endObject();
         return builder;
     }
 
+    /**
+     * Fields used for merge statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String MERGES = "merges";
         static final String CURRENT = "current";
@@ -257,6 +281,7 @@ static final class Fields {
         static final String TOTAL_SIZE_IN_BYTES = "total_size_in_bytes";
         static final String TOTAL_THROTTLE_BYTES_PER_SEC_IN_BYTES = "total_auto_throttle_in_bytes";
         static final String TOTAL_THROTTLE_BYTES_PER_SEC = "total_auto_throttle";
+        static final String UNREFERENCED_FILE_CLEANUPS_PERFORMED = "unreferenced_file_cleanups_performed";
     }
 
     @Override
@@ -272,5 +297,8 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeVLong(totalStoppedTimeInMillis);
         out.writeVLong(totalThrottledTimeInMillis);
         out.writeVLong(totalBytesPerSecAutoThrottle);
+        if (out.getVersion().onOrAfter(Version.V_2_11_0)) {
+            out.writeOptionalVLong(unreferencedFileCleanUpsPerformed);
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/merge/OnGoingMerge.java b/server/src/main/java/org/opensearch/index/merge/OnGoingMerge.java
index c42d883d612e7..59edc54d2f1ca 100644
--- a/server/src/main/java/org/opensearch/index/merge/OnGoingMerge.java
+++ b/server/src/main/java/org/opensearch/index/merge/OnGoingMerge.java
@@ -39,6 +39,8 @@
 
 /**
  * Represents a single on going merge within an index.
+ *
+ * @opensearch.internal
  */
 public class OnGoingMerge {
 
diff --git a/server/src/main/java/org/opensearch/index/merge/package-info.java b/server/src/main/java/org/opensearch/index/merge/package-info.java
new file mode 100644
index 0000000000000..b184c9e5443bd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/merge/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all merge stats requests */
+package org.opensearch.index.merge;
diff --git a/server/src/main/java/org/opensearch/index/package-info.java b/server/src/main/java/org/opensearch/index/package-info.java
new file mode 100644
index 0000000000000..0f7d564e76ee5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing operations in OpenSearch */
+package org.opensearch.index;
diff --git a/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
index 9281f1767d72d..9fb857e33bfee 100644
--- a/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
@@ -34,26 +34,26 @@
 
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.client.Client;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.geo.GeoJson;
 import org.opensearch.common.geo.GeometryIO;
 import org.opensearch.common.geo.GeometryParser;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.builders.ShapeBuilder;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
@@ -64,6 +64,8 @@
 
 /**
  * Base {@link QueryBuilder} that builds a Geometry Query
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractGeometryQueryBuilder<QB extends AbstractGeometryQueryBuilder<QB>> extends AbstractQueryBuilder<QB> {
 
@@ -522,7 +524,11 @@ protected QueryBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws
         return this;
     }
 
-    /** local class that encapsulates xcontent parsed shape parameters */
+    /**
+     * local class that encapsulates xcontent parsed shape parameters
+     *
+     * @opensearch.internal
+     */
     protected abstract static class ParsedGeometryQueryParams {
         public String fieldName;
         public ShapeRelation relation;
diff --git a/server/src/main/java/org/opensearch/index/query/AbstractQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/AbstractQueryBuilder.java
index 3ab3d099f0778..6b8dd08ed0d91 100644
--- a/server/src/main/java/org/opensearch/index/query/AbstractQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/AbstractQueryBuilder.java
@@ -36,18 +36,19 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.AbstractObjectParser;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
 import org.opensearch.common.xcontent.SuggestingErrorOnUnknown;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.math.BigInteger;
@@ -62,6 +63,8 @@
 /**
  * Base class for all classes producing lucene queries.
  * Supports conversion to BytesReference and creation of lucene Query objects.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractQueryBuilder<QB extends AbstractQueryBuilder<QB>> implements QueryBuilder {
 
@@ -392,6 +395,6 @@ protected static void declareStandardFields(AbstractObjectParser<? extends Query
 
     @Override
     public final String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/BaseTermQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/BaseTermQueryBuilder.java
index 6790d6682a799..c4d9437a60c75 100644
--- a/server/src/main/java/org/opensearch/index/query/BaseTermQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/BaseTermQueryBuilder.java
@@ -33,15 +33,20 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Base class for a TermQueryBuilder
+ *
+ * @opensearch.internal
+ */
 public abstract class BaseTermQueryBuilder<QB extends BaseTermQueryBuilder<QB>> extends AbstractQueryBuilder<QB> {
 
     public static final ParseField VALUE_FIELD = new ParseField("value");
diff --git a/server/src/main/java/org/opensearch/index/query/BoolQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/BoolQueryBuilder.java
index b23231806ea1a..c44a7ef6a397c 100644
--- a/server/src/main/java/org/opensearch/index/query/BoolQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/BoolQueryBuilder.java
@@ -37,14 +37,14 @@
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -59,6 +59,8 @@
 
 /**
  * A Query that matches documents matching boolean combinations of other queries.
+ *
+ * @opensearch.internal
  */
 public class BoolQueryBuilder extends AbstractQueryBuilder<BoolQueryBuilder> {
     public static final String NAME = "bool";
@@ -425,4 +427,35 @@ private static boolean rewriteClauses(
         }
         return changed;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (mustClauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(Occur.MUST);
+            for (QueryBuilder mustClause : mustClauses) {
+                mustClause.visit(subVisitor);
+            }
+        }
+        if (shouldClauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(Occur.SHOULD);
+            for (QueryBuilder shouldClause : shouldClauses) {
+                shouldClause.visit(subVisitor);
+            }
+        }
+        if (mustNotClauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(Occur.MUST_NOT);
+            for (QueryBuilder mustNotClause : mustNotClauses) {
+                mustNotClause.visit(subVisitor);
+            }
+        }
+        if (filterClauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(Occur.FILTER);
+            for (QueryBuilder filterClause : filterClauses) {
+                filterClause.visit(subVisitor);
+            }
+        }
+
+    }
+
 }
diff --git a/server/src/main/java/org/opensearch/index/query/BoostingQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/BoostingQueryBuilder.java
index cb50bcd6a3aa7..1b52ae2f03605 100644
--- a/server/src/main/java/org/opensearch/index/query/BoostingQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/BoostingQueryBuilder.java
@@ -33,13 +33,14 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.queries.function.FunctionScoreQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
@@ -56,6 +57,8 @@
  * are simply used to lessen the scores. Documents that match the negativeQuery have their score
  * multiplied by the supplied "boost" parameter, so this should be less than 1 to achieve a
  * demoting effect
+ *
+ * @opensearch.internal
  */
 public class BoostingQueryBuilder extends AbstractQueryBuilder<BoostingQueryBuilder> {
     public static final String NAME = "boosting";
@@ -250,4 +253,15 @@ protected void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> inner
         InnerHitContextBuilder.extractInnerHits(positiveQuery, innerHits);
         InnerHitContextBuilder.extractInnerHits(negativeQuery, innerHits);
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (positiveQuery != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(positiveQuery);
+        }
+        if (negativeQuery != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.SHOULD).accept(negativeQuery);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/CommonTermsQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/CommonTermsQueryBuilder.java
index b77b512518186..652cae86da0dc 100644
--- a/server/src/main/java/org/opensearch/index/query/CommonTermsQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/CommonTermsQueryBuilder.java
@@ -40,13 +40,13 @@
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
@@ -63,6 +63,8 @@
  *
  * @deprecated Since max_optimization optimization landed in 7.0, normal MatchQuery
  *             will achieve the same result without any configuration.
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public class CommonTermsQueryBuilder extends AbstractQueryBuilder<CommonTermsQueryBuilder> {
diff --git a/server/src/main/java/org/opensearch/index/query/ConstantScoreQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/ConstantScoreQueryBuilder.java
index 5901e32249158..b2764d29da80a 100644
--- a/server/src/main/java/org/opensearch/index/query/ConstantScoreQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/ConstantScoreQueryBuilder.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.index.query;
 
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
@@ -48,6 +49,8 @@
 /**
  * A query that wraps a filter and simply returns a constant score equal to the
  * query boost for every document in the filter.
+ *
+ * @opensearch.internal
  */
 public class ConstantScoreQueryBuilder extends AbstractQueryBuilder<ConstantScoreQueryBuilder> {
     public static final String NAME = "constant_score";
@@ -181,4 +184,11 @@ protected QueryBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws
     protected void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> innerHits) {
         InnerHitContextBuilder.extractInnerHits(filterBuilder, innerHits);
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        visitor.getChildVisitor(BooleanClause.Occur.FILTER).accept(filterBuilder);
+    }
+
 }
diff --git a/server/src/main/java/org/opensearch/index/query/DateRangeIncludingNowQuery.java b/server/src/main/java/org/opensearch/index/query/DateRangeIncludingNowQuery.java
index cd4cccc966014..001d77facb829 100644
--- a/server/src/main/java/org/opensearch/index/query/DateRangeIncludingNowQuery.java
+++ b/server/src/main/java/org/opensearch/index/query/DateRangeIncludingNowQuery.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 
@@ -44,6 +44,8 @@
  * A simple wrapper class that indicates that the wrapped query has made use of NOW
  * when parsing its datemath.  Useful for preprocessors such as the percolator that
  * need to know when not to extract dates from the query.
+ *
+ * @opensearch.internal
  */
 public class DateRangeIncludingNowQuery extends Query {
 
@@ -58,7 +60,7 @@ public Query getQuery() {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
+    public Query rewrite(IndexSearcher searcher) throws IOException {
         return in;
     }
 
diff --git a/server/src/main/java/org/opensearch/index/query/DisMaxQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/DisMaxQueryBuilder.java
index f5c97fde14baa..bd8ec62f6c43e 100644
--- a/server/src/main/java/org/opensearch/index/query/DisMaxQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/DisMaxQueryBuilder.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.index.query;
 
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.DisjunctionMaxQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -53,6 +54,8 @@
  * A query that generates the union of documents produced by its sub-queries, and that scores each document
  * with the maximum score for that document as produced by any sub-query, plus a tie breaking increment for any
  * additional matching sub-queries.
+ *
+ * @opensearch.internal
  */
 public class DisMaxQueryBuilder extends AbstractQueryBuilder<DisMaxQueryBuilder> {
     public static final String NAME = "dis_max";
@@ -244,4 +247,15 @@ protected void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> inner
             InnerHitContextBuilder.extractInnerHits(query, innerHits);
         }
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (queries.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(BooleanClause.Occur.SHOULD);
+            for (QueryBuilder subQb : queries) {
+                subVisitor.accept(subQb);
+            }
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/DistanceFeatureQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/DistanceFeatureQueryBuilder.java
index 9f6322234f32d..1d9f0479c6b17 100644
--- a/server/src/main/java/org/opensearch/index/query/DistanceFeatureQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/DistanceFeatureQueryBuilder.java
@@ -33,27 +33,29 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A query to boost scores based on their proximity to the given origin
  * for date, date_nanos and geo_point field types
+ *
+ * @opensearch.internal
  */
 public class DistanceFeatureQueryBuilder extends AbstractQueryBuilder<DistanceFeatureQueryBuilder> {
     public static final String NAME = "distance_feature";
@@ -156,6 +158,11 @@ protected boolean doEquals(DistanceFeatureQueryBuilder other) {
         return this.field.equals(other.field) && Objects.equals(this.origin, other.origin) && this.pivot.equals(other.pivot);
     }
 
+    /**
+     * Origin of a distance feature query
+     *
+     * @opensearch.internal
+     */
     public static class Origin {
         private final Object origin;
 
diff --git a/server/src/main/java/org/opensearch/index/query/ExistsQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/ExistsQueryBuilder.java
index 75c54093a8bd3..7fd83d5753512 100644
--- a/server/src/main/java/org/opensearch/index/query/ExistsQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/ExistsQueryBuilder.java
@@ -32,22 +32,20 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 
@@ -58,6 +56,8 @@
 
 /**
  * Constructs a query that only match on documents that the field has a value in them.
+ *
+ * @opensearch.internal
  */
 public class ExistsQueryBuilder extends AbstractQueryBuilder<ExistsQueryBuilder> {
     public static final String NAME = "exists";
@@ -183,12 +183,6 @@ public static Query newFilter(QueryShardContext context, String fieldPattern, bo
         return new ConstantScoreQuery(boolFilterBuilder.build());
     }
 
-    private static Query newLegacyExistsQuery(QueryShardContext context, String field) {
-        MappedFieldType fieldType = context.fieldMapper(field);
-        String fieldName = fieldType != null ? fieldType.name() : field;
-        return new TermQuery(new Term(FieldNamesFieldMapper.NAME, fieldName));
-    }
-
     private static Query newFieldExistsQuery(QueryShardContext context, String field) {
         MappedFieldType fieldType = context.getMapperService().fieldType(field);
         if (fieldType == null) {
diff --git a/server/src/main/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilder.java
index 1b095c6130a7c..1162689a54689 100644
--- a/server/src/main/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilder.java
@@ -34,19 +34,25 @@
 
 import org.apache.lucene.queries.spans.FieldMaskingSpanQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Query builder for field masking span query
+ *
+ * @opensearch.internal
+ */
 public class FieldMaskingSpanQueryBuilder extends AbstractQueryBuilder<FieldMaskingSpanQueryBuilder> implements SpanQueryBuilder {
     public static final ParseField SPAN_FIELD_MASKING_FIELD = new ParseField("span_field_masking", "field_masking_span");
 
@@ -202,4 +208,10 @@ protected boolean doEquals(FieldMaskingSpanQueryBuilder other) {
     public String getWriteableName() {
         return SPAN_FIELD_MASKING_FIELD.getPreferredName();
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(queryBuilder);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/FuzzyQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/FuzzyQueryBuilder.java
index e11cb5fabfed0..a25a426792e31 100644
--- a/server/src/main/java/org/opensearch/index/query/FuzzyQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/FuzzyQueryBuilder.java
@@ -35,15 +35,15 @@
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.support.QueryParsers;
 
@@ -52,6 +52,8 @@
 
 /**
  * A Query that does fuzzy matching for a specific value.
+ *
+ * @opensearch.internal
  */
 public class FuzzyQueryBuilder extends AbstractQueryBuilder<FuzzyQueryBuilder> implements MultiTermQueryBuilder {
     public static final String NAME = "fuzzy";
diff --git a/server/src/main/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilder.java
index 879ad07ca81fd..a4b75beab26ea 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilder.java
@@ -36,17 +36,17 @@
 import org.apache.lucene.search.Query;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Numbers;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoBoundingBox;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.SpatialStrategy;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
@@ -63,6 +63,8 @@
  *
  * This query can only operate on fields of type geo_point that have latitude and longitude
  * enabled.
+ *
+ * @opensearch.internal
  * */
 public class GeoBoundingBoxQueryBuilder extends AbstractQueryBuilder<GeoBoundingBoxQueryBuilder> {
     public static final String NAME = "geo_bounding_box";
diff --git a/server/src/main/java/org/opensearch/index/query/GeoDistanceQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/GeoDistanceQueryBuilder.java
index 9fb3ef262ab63..8d126f19a204c 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoDistanceQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoDistanceQueryBuilder.java
@@ -34,19 +34,19 @@
 
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.SpatialStrategy;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Circle;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.GeoShapeFieldMapper;
@@ -60,6 +60,8 @@
 /**
  * Filter results of a query to include only those within a specific distance to some
  * geo point.
+ *
+ * @opensearch.internal
  */
 public class GeoDistanceQueryBuilder extends AbstractQueryBuilder<GeoDistanceQueryBuilder> {
     public static final String NAME = "geo_distance";
@@ -111,7 +113,7 @@ public GeoDistanceQueryBuilder(StreamInput in) throws IOException {
         fieldName = in.readString();
         distance = in.readDouble();
         validationMethod = GeoValidationMethod.readFromStream(in);
-        center = in.readGeoPoint();
+        center = new GeoPoint(in);
         geoDistance = GeoDistance.readFromStream(in);
         ignoreUnmapped = in.readBoolean();
     }
@@ -121,7 +123,7 @@ protected void doWriteTo(StreamOutput out) throws IOException {
         out.writeString(fieldName);
         out.writeDouble(distance);
         validationMethod.writeTo(out);
-        out.writeGeoPoint(center);
+        center.writeTo(out);
         geoDistance.writeTo(out);
         out.writeBoolean(ignoreUnmapped);
     }
diff --git a/server/src/main/java/org/opensearch/index/query/GeoExecType.java b/server/src/main/java/org/opensearch/index/query/GeoExecType.java
index da1c26e0abbd9..39248d4e8edb6 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoExecType.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoExecType.java
@@ -33,13 +33,17 @@
 package org.opensearch.index.query;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
-/** Specifies how a geo query should be run. */
+/**
+ * Specifies how a geo query should be run.
+ *
+ * @opensearch.internal
+ */
 public enum GeoExecType implements Writeable {
 
     MEMORY(0),
diff --git a/server/src/main/java/org/opensearch/index/query/GeoPolygonQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/GeoPolygonQueryBuilder.java
index c6a3fbded13c0..47eafa3893384 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoPolygonQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoPolygonQueryBuilder.java
@@ -38,16 +38,16 @@
 import org.apache.lucene.search.IndexOrDocValuesQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.GeoPointFieldMapper.GeoPointFieldType;
 import org.opensearch.index.mapper.MappedFieldType;
 
@@ -56,6 +56,11 @@
 import java.util.List;
 import java.util.Objects;
 
+/**
+ * Query builder for polygon queries
+ *
+ * @opensearch.internal
+ */
 public class GeoPolygonQueryBuilder extends AbstractQueryBuilder<GeoPolygonQueryBuilder> {
     public static final String NAME = "geo_polygon";
 
@@ -109,7 +114,7 @@ public GeoPolygonQueryBuilder(StreamInput in) throws IOException {
         int size = in.readVInt();
         shell = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
-            shell.add(in.readGeoPoint());
+            shell.add(new GeoPoint(in));
         }
         validationMethod = GeoValidationMethod.readFromStream(in);
         ignoreUnmapped = in.readBoolean();
@@ -120,7 +125,7 @@ protected void doWriteTo(StreamOutput out) throws IOException {
         out.writeString(fieldName);
         out.writeVInt(shell.size());
         for (GeoPoint point : shell) {
-            out.writeGeoPoint(point);
+            point.writeTo(out);
         }
         validationMethod.writeTo(out);
         out.writeBoolean(ignoreUnmapped);
diff --git a/server/src/main/java/org/opensearch/index/query/GeoShapeQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/GeoShapeQueryBuilder.java
index 161c6e64c7bf3..e029884f32531 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoShapeQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoShapeQueryBuilder.java
@@ -34,16 +34,16 @@
 
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.SpatialStrategy;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.index.mapper.GeoShapeQueryable;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -57,6 +57,8 @@
  * can be applied to any {@link MappedFieldType} that implements {@link GeoShapeQueryable}.
  *
  * GeoJson and WKT shape definitions are supported
+ *
+ * @opensearch.internal
  */
 public class GeoShapeQueryBuilder extends AbstractGeometryQueryBuilder<GeoShapeQueryBuilder> {
     public static final String NAME = "geo_shape";
@@ -229,6 +231,11 @@ protected GeoShapeQueryBuilder doRewrite(QueryRewriteContext queryRewriteContext
         return builder;
     }
 
+    /**
+     * Geoshape query parameters that have been parsed from xcontent
+     *
+     * @opensearch.internal
+     */
     private static class ParsedGeoShapeQueryParams extends ParsedGeometryQueryParams {
         SpatialStrategy strategy;
 
diff --git a/server/src/main/java/org/opensearch/index/query/GeoValidationMethod.java b/server/src/main/java/org/opensearch/index/query/GeoValidationMethod.java
index 45c90727fbb8b..559c084325abb 100644
--- a/server/src/main/java/org/opensearch/index/query/GeoValidationMethod.java
+++ b/server/src/main/java/org/opensearch/index/query/GeoValidationMethod.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
 
@@ -46,7 +46,9 @@
  *  On STRICT validation invalid coordinates cause an exception to be thrown.
  *  On IGNORE_MALFORMED invalid coordinates are being accepted.
  *  On COERCE invalid coordinates are being corrected to the most likely valid coordinate.
- * */
+ *
+ * @opensearch.internal
+ */
 public enum GeoValidationMethod implements Writeable {
     COERCE,
     IGNORE_MALFORMED,
diff --git a/server/src/main/java/org/opensearch/index/query/IdsQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/IdsQueryBuilder.java
index 724425957f75a..e2cf764128a12 100644
--- a/server/src/main/java/org/opensearch/index/query/IdsQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/IdsQueryBuilder.java
@@ -34,15 +34,15 @@
 
 import org.apache.lucene.search.Query;
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 
@@ -54,10 +54,12 @@
 import java.util.Objects;
 import java.util.Set;
 
-import static org.opensearch.common.xcontent.ObjectParser.fromList;
+import static org.opensearch.core.xcontent.ObjectParser.fromList;
 
 /**
  * A query that will return only documents matching specific ids (and a type).
+ *
+ * @opensearch.internal
  */
 public class IdsQueryBuilder extends AbstractQueryBuilder<IdsQueryBuilder> {
     public static final String NAME = "ids";
diff --git a/server/src/main/java/org/opensearch/index/query/InnerHitBuilder.java b/server/src/main/java/org/opensearch/index/query/InnerHitBuilder.java
index a1e041ba24080..d2a02c66c0bfc 100644
--- a/server/src/main/java/org/opensearch/index/query/InnerHitBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/InnerHitBuilder.java
@@ -33,16 +33,17 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder.ScriptField;
@@ -62,8 +63,11 @@
 import java.util.Objects;
 import java.util.Set;
 
-import static org.opensearch.common.xcontent.XContentParser.Token.END_OBJECT;
+import static org.opensearch.core.xcontent.XContentParser.Token.END_OBJECT;
 
+/**
+ * Query builder for inner hits
+ */
 public final class InnerHitBuilder implements Writeable, ToXContentObject {
 
     public static final ParseField NAME_FIELD = new ParseField("name");
@@ -601,6 +605,6 @@ public static InnerHitBuilder fromXContent(XContentParser parser) throws IOExcep
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/InnerHitContextBuilder.java b/server/src/main/java/org/opensearch/index/query/InnerHitContextBuilder.java
index 10efb18dc0cfa..8c4c001ffb135 100644
--- a/server/src/main/java/org/opensearch/index/query/InnerHitContextBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/InnerHitContextBuilder.java
@@ -49,6 +49,8 @@
 
 /**
  * A builder for {@link InnerHitsContext.InnerHitSubContext}
+ *
+ * @opensearch.internal
  */
 public abstract class InnerHitContextBuilder {
     protected final QueryBuilder query;
diff --git a/server/src/main/java/org/opensearch/index/query/IntervalBuilder.java b/server/src/main/java/org/opensearch/index/query/IntervalBuilder.java
index e91adc5abe27a..0e42e79f67d0c 100644
--- a/server/src/main/java/org/opensearch/index/query/IntervalBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/IntervalBuilder.java
@@ -39,12 +39,12 @@
 import org.apache.lucene.analysis.tokenattributes.PositionLengthAttribute;
 import org.apache.lucene.analysis.tokenattributes.TermToBytesRefAttribute;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.queries.intervals.IntervalMatchesIterator;
-import org.apache.lucene.search.BooleanQuery;
-import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.queries.intervals.IntervalIterator;
+import org.apache.lucene.queries.intervals.IntervalMatchesIterator;
 import org.apache.lucene.queries.intervals.Intervals;
 import org.apache.lucene.queries.intervals.IntervalsSource;
+import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.graph.GraphTokenStreamFiniteStrings;
 
@@ -57,6 +57,8 @@
 
 /**
  * Constructs an IntervalsSource based on analyzed text
+ *
+ * @opensearch.internal
  */
 public class IntervalBuilder {
 
diff --git a/server/src/main/java/org/opensearch/index/query/IntervalFilterScript.java b/server/src/main/java/org/opensearch/index/query/IntervalFilterScript.java
index 0e9ed2cc557f6..f94a8bf0f310c 100644
--- a/server/src/main/java/org/opensearch/index/query/IntervalFilterScript.java
+++ b/server/src/main/java/org/opensearch/index/query/IntervalFilterScript.java
@@ -38,9 +38,16 @@
 
 /**
  * Base class for scripts used as interval filters, see {@link IntervalsSourceProvider.IntervalFilter}
+ *
+ * @opensearch.internal
  */
 public abstract class IntervalFilterScript {
 
+    /**
+     * Internal interval
+     *
+     * @opensearch.internal
+     */
     public static class Interval {
 
         private IntervalIterator iterator;
@@ -64,6 +71,11 @@ public int getGaps() {
 
     public abstract boolean execute(Interval interval);
 
+    /**
+     * Factory to create a script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         IntervalFilterScript newInstance();
     }
diff --git a/server/src/main/java/org/opensearch/index/query/IntervalMode.java b/server/src/main/java/org/opensearch/index/query/IntervalMode.java
index f0489bf452678..454d867b41da2 100644
--- a/server/src/main/java/org/opensearch/index/query/IntervalMode.java
+++ b/server/src/main/java/org/opensearch/index/query/IntervalMode.java
@@ -9,12 +9,17 @@
 package org.opensearch.index.query;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Mode for Text and Mapped Field Types
+ *
+ * @opensearch.internal
+ */
 public enum IntervalMode implements Writeable {
     ORDERED(0),
     UNORDERED(1),
diff --git a/server/src/main/java/org/opensearch/index/query/IntervalQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/IntervalQueryBuilder.java
index 13dd60d3c2a0f..125035ea5e95a 100644
--- a/server/src/main/java/org/opensearch/index/query/IntervalQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/IntervalQueryBuilder.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.index.query;
 
+import org.apache.lucene.queries.intervals.IntervalQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.queries.intervals.IntervalQuery;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
@@ -49,6 +49,8 @@
 
 /**
  * Builder for {@link IntervalQuery}
+ *
+ * @opensearch.internal
  */
 public class IntervalQueryBuilder extends AbstractQueryBuilder<IntervalQueryBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/index/query/IntervalsSourceProvider.java b/server/src/main/java/org/opensearch/index/query/IntervalsSourceProvider.java
index b53dfc32d7006..791020c248630 100644
--- a/server/src/main/java/org/opensearch/index/query/IntervalsSourceProvider.java
+++ b/server/src/main/java/org/opensearch/index/query/IntervalsSourceProvider.java
@@ -43,19 +43,19 @@
 import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.script.Script;
@@ -67,8 +67,8 @@
 import java.util.Objects;
 import java.util.Set;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Factory class for {@link IntervalsSource}
@@ -77,6 +77,8 @@
  * to a proximity source (phrase, ordered, unordered, unordered without overlaps depending on how
  * strict the matching should be); {@link Combine}, which allows proximity queries
  * between different sub-sources; and {@link Disjunction}.
+ *
+ * @opensearch.internal
  */
 public abstract class IntervalsSourceProvider implements NamedWriteable, ToXContentFragment {
 
@@ -125,6 +127,11 @@ private static IntervalsSourceProvider parseInnerIntervals(XContentParser parser
         return isp;
     }
 
+    /**
+     * Match interval
+     *
+     * @opensearch.internal
+     */
     public static class Match extends IntervalsSourceProvider {
 
         public static final String NAME = "match";
@@ -310,6 +317,11 @@ String getUseField() {
         }
     }
 
+    /**
+     * Disjunction interval
+     *
+     * @opensearch.internal
+     */
     public static class Disjunction extends IntervalsSourceProvider {
 
         public static final String NAME = "any_of";
@@ -415,6 +427,11 @@ IntervalFilter getFilter() {
         }
     }
 
+    /**
+     * Combine interval
+     *
+     * @opensearch.internal
+     */
     public static class Combine extends IntervalsSourceProvider {
 
         public static final String NAME = "all_of";
@@ -565,6 +582,11 @@ IntervalFilter getFilter() {
         }
     }
 
+    /**
+     * Prefix interval
+     *
+     * @opensearch.internal
+     */
     public static class Prefix extends IntervalsSourceProvider {
 
         public static final String NAME = "prefix";
@@ -679,6 +701,11 @@ String getUseField() {
         }
     }
 
+    /**
+     * Regular expression interval
+     *
+     * @opensearch.internal
+     */
     public static class Regexp extends IntervalsSourceProvider {
 
         public static final String NAME = "regexp";
@@ -858,6 +885,11 @@ boolean isCaseInsensitive() {
         }
     }
 
+    /**
+     * Wildcard interval
+     *
+     * @opensearch.internal
+     */
     public static class Wildcard extends IntervalsSourceProvider {
 
         public static final String NAME = "wildcard";
@@ -1008,6 +1040,11 @@ Integer getMaxExpansions() {
         }
     }
 
+    /**
+     * Fuzzy interval
+     *
+     * @opensearch.internal
+     */
     public static class Fuzzy extends IntervalsSourceProvider {
 
         public static final String NAME = "fuzzy";
@@ -1178,6 +1215,11 @@ String getUseField() {
         }
     }
 
+    /**
+     * Script filter source
+     *
+     * @opensearch.internal
+     */
     static class ScriptFilterSource extends FilteredIntervalsSource {
 
         final IntervalFilterScript script;
@@ -1195,6 +1237,11 @@ protected boolean accept(IntervalIterator it) {
         }
     }
 
+    /**
+     * An interval filter
+     *
+     * @opensearch.internal
+     */
     public static class IntervalFilter implements ToXContentObject, Writeable {
 
         public static final String NAME = "filter";
diff --git a/server/src/main/java/org/opensearch/index/query/LegacyGeoShapeQueryProcessor.java b/server/src/main/java/org/opensearch/index/query/LegacyGeoShapeQueryProcessor.java
index d16bdb8ac6327..c3437fbf4dda6 100644
--- a/server/src/main/java/org/opensearch/index/query/LegacyGeoShapeQueryProcessor.java
+++ b/server/src/main/java/org/opensearch/index/query/LegacyGeoShapeQueryProcessor.java
@@ -67,14 +67,23 @@
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.index.mapper.AbstractShapeGeometryFieldMapper;
 import org.opensearch.index.mapper.LegacyGeoShapeFieldMapper;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.Shape;
 
 import java.util.ArrayList;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Shape;
+
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
+/**
+ * Query Processor for Legacy Geo Shape types (prefix trees)
+ *
+ * @opensearch.internal
+ *
+ * @deprecated this will be removed in a future release
+ */
+@Deprecated
 public class LegacyGeoShapeQueryProcessor {
 
     private AbstractShapeGeometryFieldMapper.AbstractShapeGeometryFieldType ft;
diff --git a/server/src/main/java/org/opensearch/index/query/MatchAllQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchAllQueryBuilder.java
index ba51ec82e4667..c62ee0ac39584 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchAllQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchAllQueryBuilder.java
@@ -33,18 +33,20 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * A query that matches on all documents.
+ *
+ * @opensearch.internal
  */
 public class MatchAllQueryBuilder extends AbstractQueryBuilder<MatchAllQueryBuilder> {
     public static final String NAME = "match_all";
diff --git a/server/src/main/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilder.java
index b6a85e2936b20..9a8d2ab104799 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilder.java
@@ -34,15 +34,15 @@
 
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.support.QueryParsers;
 import org.opensearch.index.search.MatchQuery;
 
@@ -58,6 +58,8 @@
 /**
  * The boolean prefix query analyzes the input text and creates a boolean query containing a Term query for each term, except
  * for the last term, which is used to create a prefix query
+ *
+ * @opensearch.internal
  */
 public class MatchBoolPrefixQueryBuilder extends AbstractQueryBuilder<MatchBoolPrefixQueryBuilder> {
 
@@ -173,12 +175,19 @@ public String minimumShouldMatch() {
         return this.minimumShouldMatch;
     }
 
+    @Deprecated
     /** Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO". */
     public MatchBoolPrefixQueryBuilder fuzziness(Object fuzziness) {
         this.fuzziness = Fuzziness.build(fuzziness);
         return this;
     }
 
+    /** Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO". */
+    public MatchBoolPrefixQueryBuilder fuzziness(Fuzziness fuzziness) {
+        this.fuzziness = fuzziness;
+        return this;
+    }
+
     /**  Gets the fuzziness used when evaluated to a fuzzy query type. */
     public Fuzziness fuzziness() {
         return this.fuzziness;
@@ -346,19 +355,16 @@ public static MatchBoolPrefixQueryBuilder fromXContent(XContentParser parser) th
             }
         }
 
-        MatchBoolPrefixQueryBuilder queryBuilder = new MatchBoolPrefixQueryBuilder(fieldName, value);
-        queryBuilder.analyzer(analyzer);
-        queryBuilder.operator(operator);
-        queryBuilder.minimumShouldMatch(minimumShouldMatch);
-        queryBuilder.boost(boost);
-        queryBuilder.queryName(queryName);
-        if (fuzziness != null) {
-            queryBuilder.fuzziness(fuzziness);
-        }
-        queryBuilder.prefixLength(prefixLength);
-        queryBuilder.maxExpansions(maxExpansion);
-        queryBuilder.fuzzyTranspositions(fuzzyTranspositions);
-        queryBuilder.fuzzyRewrite(fuzzyRewrite);
+        MatchBoolPrefixQueryBuilder queryBuilder = new MatchBoolPrefixQueryBuilder(fieldName, value).analyzer(analyzer)
+            .operator(operator)
+            .minimumShouldMatch(minimumShouldMatch)
+            .boost(boost)
+            .queryName(queryName)
+            .fuzziness(fuzziness)
+            .prefixLength(prefixLength)
+            .maxExpansions(maxExpansion)
+            .fuzzyTranspositions(fuzzyTranspositions)
+            .fuzzyRewrite(fuzzyRewrite);
         return queryBuilder;
     }
 
diff --git a/server/src/main/java/org/opensearch/index/query/MatchNoneQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchNoneQueryBuilder.java
index f71f1fac9094d..17e84bc785206 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchNoneQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchNoneQueryBuilder.java
@@ -33,17 +33,19 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * A query that matches no document.
+ *
+ * @opensearch.internal
  */
 public class MatchNoneQueryBuilder extends AbstractQueryBuilder<MatchNoneQueryBuilder> {
     public static final String NAME = "match_none";
diff --git a/server/src/main/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilder.java
index 3ee3c25837f37..8aa318af69222 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilder.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
 
@@ -50,6 +50,8 @@
 /**
  * Match query is a query that analyzes the text and constructs a phrase prefix
  * query as the result of the analysis.
+ *
+ * @opensearch.internal
  */
 public class MatchPhrasePrefixQueryBuilder extends AbstractQueryBuilder<MatchPhrasePrefixQueryBuilder> {
     public static final String NAME = "match_phrase_prefix";
diff --git a/server/src/main/java/org/opensearch/index/query/MatchPhraseQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchPhraseQueryBuilder.java
index 03d00841db79a..6cdf6c6600304 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchPhraseQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchPhraseQueryBuilder.java
@@ -33,13 +33,13 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
 
@@ -49,6 +49,8 @@
 /**
  * Match query is a query that analyzes the text and constructs a phrase query
  * as the result of the analysis.
+ *
+ * @opensearch.internal
  */
 public class MatchPhraseQueryBuilder extends AbstractQueryBuilder<MatchPhraseQueryBuilder> {
     public static final String NAME = "match_phrase";
diff --git a/server/src/main/java/org/opensearch/index/query/MatchQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MatchQueryBuilder.java
index 54c0f79dbac92..844d47070923b 100644
--- a/server/src/main/java/org/opensearch/index/query/MatchQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MatchQueryBuilder.java
@@ -34,15 +34,15 @@
 
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.support.QueryParsers;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
@@ -53,6 +53,8 @@
 /**
  * Match query is a query that analyzes the text and constructs a query as the
  * result of the analysis.
+ *
+ * @opensearch.internal
  */
 public class MatchQueryBuilder extends AbstractQueryBuilder<MatchQueryBuilder> {
 
@@ -206,12 +208,19 @@ public String analyzer() {
         return this.analyzer;
     }
 
+    @Deprecated
     /** Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO". */
     public MatchQueryBuilder fuzziness(Object fuzziness) {
         this.fuzziness = Fuzziness.build(fuzziness);
         return this;
     }
 
+    /** Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO". */
+    public MatchQueryBuilder fuzziness(Fuzziness fuzziness) {
+        this.fuzziness = fuzziness;
+        return this;
+    }
+
     /**  Gets the fuzziness used when evaluated to a fuzzy query type. */
     public Fuzziness fuzziness() {
         return this.fuzziness;
@@ -563,9 +572,7 @@ public static MatchQueryBuilder fromXContent(XContentParser parser) throws IOExc
         matchQuery.operator(operator);
         matchQuery.analyzer(analyzer);
         matchQuery.minimumShouldMatch(minimumShouldMatch);
-        if (fuzziness != null) {
-            matchQuery.fuzziness(fuzziness);
-        }
+        matchQuery.fuzziness(fuzziness);
         matchQuery.fuzzyRewrite(fuzzyRewrite);
         matchQuery.prefixLength(prefixLength);
         matchQuery.fuzzyTranspositions(fuzzyTranspositions);
diff --git a/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
index 1ecc88387e549..831cdb6f24147 100644
--- a/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
@@ -37,8 +37,8 @@
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.OpenSearchParseException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.termvectors.MultiTermVectorsItemResponse;
@@ -48,21 +48,23 @@
 import org.opensearch.action.termvectors.TermVectorsResponse;
 import org.opensearch.client.Client;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.search.MoreLikeThisQuery;
 import org.opensearch.common.lucene.search.XMoreLikeThis;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper.KeywordFieldType;
@@ -87,6 +89,8 @@
  * A more like this query that finds documents that are "like" the provided set of document(s).
  *
  * The documents are provided as a set of strings and/or a list of {@link Item}.
+ *
+ * @opensearch.internal
  */
 public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQueryBuilder> {
     public static final String NAME = "more_like_this";
@@ -159,6 +163,8 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
 
     /**
      * A single item to be used for a {@link MoreLikeThisQueryBuilder}.
+     *
+     * @opensearch.internal
      */
     public static final class Item implements ToXContentObject, Writeable {
         public static final Item[] EMPTY_ARRAY = new Item[0];
@@ -166,7 +172,7 @@ public static final class Item implements ToXContentObject, Writeable {
         private String index;
         private String id;
         private BytesReference doc;
-        private XContentType xContentType;
+        private MediaType mediaType;
         private String[] fields;
         private Map<String, String> perFieldAnalyzer;
         private String routing;
@@ -183,7 +189,7 @@ public Item() {}
             this.id = copy.id;
             this.routing = copy.routing;
             this.doc = copy.doc;
-            this.xContentType = copy.xContentType;
+            this.mediaType = copy.mediaType;
             this.fields = copy.fields;
             this.perFieldAnalyzer = copy.perFieldAnalyzer;
             this.version = copy.version;
@@ -216,7 +222,7 @@ public Item(@Nullable String index, XContentBuilder doc) {
             }
             this.index = index;
             this.doc = BytesReference.bytes(doc);
-            this.xContentType = doc.contentType();
+            this.mediaType = doc.contentType();
         }
 
         /**
@@ -230,7 +236,11 @@ public Item(@Nullable String index, XContentBuilder doc) {
             }
             if (in.readBoolean()) {
                 doc = (BytesReference) in.readGenericValue();
-                xContentType = in.readEnum(XContentType.class);
+                if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                    mediaType = in.readMediaType();
+                } else {
+                    mediaType = in.readEnum(XContentType.class);
+                }
             } else {
                 id = in.readString();
             }
@@ -251,7 +261,11 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(doc != null);
             if (doc != null) {
                 out.writeGenericValue(doc);
-                out.writeEnum(xContentType);
+                if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                    mediaType.writeTo(out);
+                } else {
+                    out.writeEnum((XContentType) mediaType);
+                }
             } else {
                 out.writeString(id);
             }
@@ -327,8 +341,8 @@ public Item versionType(VersionType versionType) {
             return this;
         }
 
-        XContentType xContentType() {
-            return xContentType;
+        MediaType mediaType() {
+            return mediaType;
         }
 
         /**
@@ -347,7 +361,7 @@ TermVectorsRequest toTermVectorsRequest() {
                 .termStatistics(false);
             // for artificial docs to make sure that the id has changed in the item too
             if (doc != null) {
-                termVectorsRequest.doc(doc, true, xContentType);
+                termVectorsRequest.doc(doc, true, mediaType);
                 this.id = termVectorsRequest.id();
             }
             return termVectorsRequest;
@@ -369,7 +383,7 @@ public static Item parse(XContentParser parser, Item item) throws IOException {
                         item.id = parser.text();
                     } else if (DOC.match(currentFieldName, parser.getDeprecationHandler())) {
                         item.doc = BytesReference.bytes(jsonBuilder().copyCurrentStructure(parser));
-                        item.xContentType = XContentType.JSON;
+                        item.mediaType = MediaTypeRegistry.JSON;
                     } else if (FIELDS.match(currentFieldName, parser.getDeprecationHandler())) {
                         if (token == XContentParser.Token.START_ARRAY) {
                             List<String> fields = new ArrayList<>();
@@ -415,7 +429,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             }
             if (this.doc != null) {
                 try (InputStream stream = this.doc.streamInput()) {
-                    builder.rawField(DOC.getPreferredName(), stream, xContentType);
+                    builder.rawField(DOC.getPreferredName(), stream, mediaType);
                 }
             }
             if (this.fields != null) {
@@ -442,7 +456,7 @@ public String toString() {
                 XContentBuilder builder = XContentFactory.jsonBuilder();
                 builder.prettyPrint();
                 toXContent(builder, EMPTY_PARAMS);
-                return Strings.toString(builder);
+                return builder.toString();
             } catch (Exception e) {
                 return "{ \"error\" : \"" + ExceptionsHelper.detailedMessage(e) + "\"}";
             }
diff --git a/server/src/main/java/org/opensearch/index/query/MultiMatchQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MultiMatchQueryBuilder.java
index 3a130f395539f..2f04d025a6abe 100644
--- a/server/src/main/java/org/opensearch/index/query/MultiMatchQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MultiMatchQueryBuilder.java
@@ -36,17 +36,17 @@
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.DeprecationHandler;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.support.QueryParsers;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.index.search.MultiMatchQuery;
@@ -62,6 +62,8 @@
 
 /**
  * Same as {@link MatchQueryBuilder} but supports multiple fields.
+ *
+ * @opensearch.internal
  */
 public class MultiMatchQueryBuilder extends AbstractQueryBuilder<MultiMatchQueryBuilder> {
 
@@ -115,6 +117,11 @@ public class MultiMatchQueryBuilder extends AbstractQueryBuilder<MultiMatchQuery
     private boolean autoGenerateSynonymsPhraseQuery = true;
     private boolean fuzzyTranspositions = DEFAULT_FUZZY_TRANSPOSITIONS;
 
+    /**
+     * Type of the match
+     *
+     * @opensearch.internal
+     */
     public enum Type implements Writeable {
 
         /**
@@ -397,6 +404,7 @@ public int slop() {
         return slop;
     }
 
+    @Deprecated
     /**
      * Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO".
      */
@@ -407,6 +415,14 @@ public MultiMatchQueryBuilder fuzziness(Object fuzziness) {
         return this;
     }
 
+    /**
+     * Sets the fuzziness used when evaluated to a fuzzy query type. Defaults to "AUTO".
+     */
+    public MultiMatchQueryBuilder fuzziness(Fuzziness fuzziness) {
+        this.fuzziness = fuzziness;
+        return this;
+    }
+
     public Fuzziness fuzziness() {
         return fuzziness;
     }
diff --git a/server/src/main/java/org/opensearch/index/query/MultiTermQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MultiTermQueryBuilder.java
index c88e8ce5fbfb0..b8e88da4741bb 100644
--- a/server/src/main/java/org/opensearch/index/query/MultiTermQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MultiTermQueryBuilder.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.index.query;
 
+/**
+ * Base interface for multi term queries
+ *
+ * @opensearch.internal
+ */
 public interface MultiTermQueryBuilder extends QueryBuilder {
     /**
      * Get the field name for this query.
diff --git a/server/src/main/java/org/opensearch/index/query/NestedQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/NestedQueryBuilder.java
index 52a7635d708f5..176dec5249156 100644
--- a/server/src/main/java/org/opensearch/index/query/NestedQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/NestedQueryBuilder.java
@@ -49,18 +49,18 @@
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.search.MaxScoreCollector;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ObjectMapper;
-import org.opensearch.index.search.OpenSearchToParentBlockJoinQuery;
 import org.opensearch.index.search.NestedHelper;
+import org.opensearch.index.search.OpenSearchToParentBlockJoinQuery;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.fetch.subphase.InnerHitsContext;
 import org.opensearch.search.internal.SearchContext;
@@ -74,6 +74,11 @@
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 import static org.opensearch.search.fetch.subphase.InnerHitsContext.intersect;
 
+/**
+ * Query builder for nested queries
+ *
+ * @opensearch.internal
+ */
 public class NestedQueryBuilder extends AbstractQueryBuilder<NestedQueryBuilder> {
     public static final String NAME = "nested";
     /**
@@ -306,10 +311,13 @@ protected Query doToQuery(QueryShardContext context) throws IOException {
             parentFilter = context.bitsetFilter(objectMapper.nestedTypeFilter());
         }
 
+        BitSetProducer previousParentFilter = context.getParentFilter();
         try {
+            context.setParentFilter(parentFilter);
             context.nestedScope().nextLevel(nestedObjectMapper);
             innerQuery = this.query.toQuery(context);
         } finally {
+            context.setParentFilter(previousParentFilter);
             context.nestedScope().previousLevel();
         }
 
@@ -353,6 +361,11 @@ public void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> innerHit
         }
     }
 
+    /**
+     * Context builder for nested inner hits
+     *
+     * @opensearch.internal
+     */
     static class NestedInnerHitContextBuilder extends InnerHitContextBuilder {
         private final String path;
 
@@ -391,6 +404,11 @@ protected void doBuild(SearchContext parentSearchContext, InnerHitsContext inner
         }
     }
 
+    /**
+     * Inner hits sub context
+     *
+     * @opensearch.internal
+     */
     static final class NestedInnerHitSubContext extends InnerHitsContext.InnerHitSubContext {
 
         private final ObjectMapper parentObjectMapper;
diff --git a/server/src/main/java/org/opensearch/index/query/Operator.java b/server/src/main/java/org/opensearch/index/query/Operator.java
index 3963ca97a42d4..ee8c93ce76ecb 100644
--- a/server/src/main/java/org/opensearch/index/query/Operator.java
+++ b/server/src/main/java/org/opensearch/index/query/Operator.java
@@ -33,14 +33,19 @@
 
 import org.apache.lucene.queryparser.classic.QueryParser;
 import org.apache.lucene.search.BooleanClause;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
 
 import java.io.IOException;
 import java.util.Locale;
 
+/**
+ * Boolean operators
+ *
+ * @opensearch.internal
+ */
 public enum Operator implements Writeable {
     OR,
     AND;
diff --git a/server/src/main/java/org/opensearch/index/query/ParsedQuery.java b/server/src/main/java/org/opensearch/index/query/ParsedQuery.java
index 57ed444660686..5d9f67ac365b9 100644
--- a/server/src/main/java/org/opensearch/index/query/ParsedQuery.java
+++ b/server/src/main/java/org/opensearch/index/query/ParsedQuery.java
@@ -41,6 +41,8 @@
 
 /**
  * The result of parsing a query.
+ *
+ * @opensearch.internal
  */
 public class ParsedQuery {
     private final Query query;
diff --git a/server/src/main/java/org/opensearch/index/query/PrefixQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/PrefixQueryBuilder.java
index 1d2a07c99374b..0f4d6140db2c7 100644
--- a/server/src/main/java/org/opensearch/index/query/PrefixQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/PrefixQueryBuilder.java
@@ -37,16 +37,16 @@
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ConstantFieldType;
+import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.support.QueryParsers;
 
 import java.io.IOException;
@@ -54,6 +54,8 @@
 
 /**
  * A Query that matches documents containing terms with a specified prefix.
+ *
+ * @opensearch.internal
  */
 public class PrefixQueryBuilder extends AbstractQueryBuilder<PrefixQueryBuilder> implements MultiTermQueryBuilder {
     public static final String NAME = "prefix";
diff --git a/server/src/main/java/org/opensearch/index/query/QueryBuilder.java b/server/src/main/java/org/opensearch/index/query/QueryBuilder.java
index 0ae9668192242..090f74c5be7fe 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryBuilder.java
@@ -33,11 +33,16 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 import java.io.IOException;
 
+/**
+ * Foundation class for all OpenSearch query builders
+ *
+ * @opensearch.internal
+ */
 public interface QueryBuilder extends NamedWriteable, ToXContentObject, Rewriteable<QueryBuilder> {
 
     /**
@@ -90,4 +95,13 @@ public interface QueryBuilder extends NamedWriteable, ToXContentObject, Rewritea
     default QueryBuilder rewrite(QueryRewriteContext queryShardContext) throws IOException {
         return this;
     }
+
+    /**
+     * Recurse through the QueryBuilder tree, visiting any child QueryBuilder.
+     * @param visitor a query builder visitor to be called by each query builder in the tree.
+     */
+    default void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+    };
+
 }
diff --git a/server/src/main/java/org/opensearch/index/query/QueryBuilderVisitor.java b/server/src/main/java/org/opensearch/index/query/QueryBuilderVisitor.java
new file mode 100644
index 0000000000000..af5a125f9dd95
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/QueryBuilderVisitor.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.query;
+
+import org.apache.lucene.search.BooleanClause;
+
+/**
+ * QueryBuilderVisitor is an interface to define Visitor Object to be traversed in QueryBuilder tree.
+ */
+public interface QueryBuilderVisitor {
+
+    /**
+     * Accept method is called when the visitor accepts the queryBuilder object to be traversed in the query tree.
+     * @param qb is a queryBuilder object which is accepeted by the visitor.
+     */
+    void accept(QueryBuilder qb);
+
+    /**
+     * Fetches the child sub visitor from the main QueryBuilderVisitor Object.
+     * @param occur defines the occurrence of the result fetched from the search query in the final search result.
+     * @return a child queryBuilder Visitor Object.
+     */
+    QueryBuilderVisitor getChildVisitor(BooleanClause.Occur occur);
+
+    /**
+     *  NoopQueryVisitor is a default implementation of QueryBuilderVisitor.
+     *  When a user does not want to implement QueryBuilderVisitor and have to just pass an empty object then this class will be used.
+     *
+     */
+    QueryBuilderVisitor NO_OP_VISITOR = new QueryBuilderVisitor() {
+        @Override
+        public void accept(QueryBuilder qb) {
+            // Do nothing
+        }
+
+        @Override
+        public QueryBuilderVisitor getChildVisitor(BooleanClause.Occur occur) {
+            return this;
+        }
+    };
+
+}
diff --git a/server/src/main/java/org/opensearch/index/query/QueryBuilders.java b/server/src/main/java/org/opensearch/index/query/QueryBuilders.java
index 7ea12fdc6406b..387d21830aa38 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryBuilders.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryBuilders.java
@@ -34,10 +34,10 @@
 
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.builders.ShapeBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.index.query.DistanceFeatureQueryBuilder.Origin;
 import org.opensearch.index.query.MoreLikeThisQueryBuilder.Item;
@@ -53,6 +53,8 @@
 
 /**
  * Utility class to create search queries.
+ *
+ * @opensearch.internal
  */
 public final class QueryBuilders {
 
diff --git a/server/src/main/java/org/opensearch/index/query/QueryParser.java b/server/src/main/java/org/opensearch/index/query/QueryParser.java
index e01b2bd844282..1eefb87f6e2b2 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryParser.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryParser.java
@@ -32,12 +32,15 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
- * Defines a query parser that is able to parse {@link QueryBuilder}s from {@link org.opensearch.common.xcontent.XContent}.
+ * Defines a query parser that is able to parse {@link QueryBuilder}s from {@link XContent}.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface QueryParser<QB extends QueryBuilder> {
diff --git a/server/src/main/java/org/opensearch/index/query/QueryRewriteContext.java b/server/src/main/java/org/opensearch/index/query/QueryRewriteContext.java
index 720ee077119d6..1f7805ec99cd4 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryRewriteContext.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryRewriteContext.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.client.Client;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -45,6 +45,8 @@
 
 /**
  * Context object used to rewrite {@link QueryBuilder} instances into simplified version.
+ *
+ * @opensearch.internal
  */
 public class QueryRewriteContext {
     private final NamedXContentRegistry xContentRegistry;
diff --git a/server/src/main/java/org/opensearch/index/query/QueryShardContext.java b/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
index bfc0490e507db..701484fbc8dc3 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
@@ -38,19 +38,19 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.join.BitSetProducer;
 import org.apache.lucene.search.similarities.Similarity;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.client.Client;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.IndexSortConfig;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -89,6 +89,8 @@
 
 /**
  * Context object used to create lucene queries on the shard level.
+ *
+ * @opensearch.internal
  */
 public class QueryShardContext extends QueryRewriteContext {
 
@@ -113,6 +115,7 @@ public class QueryShardContext extends QueryRewriteContext {
     private boolean mapUnmappedFieldAsString;
     private NestedScope nestedScope;
     private final ValuesSourceRegistry valuesSourceRegistry;
+    private BitSetProducer parentFilter;
 
     public QueryShardContext(
         int shardId,
@@ -620,4 +623,12 @@ public BitsetFilterCache getBitsetFilterCache() {
     public AggregationUsageService getUsageService() {
         return valuesSourceRegistry.getUsageService();
     }
+
+    public BitSetProducer getParentFilter() {
+        return parentFilter;
+    }
+
+    public void setParentFilter(BitSetProducer parentFilter) {
+        this.parentFilter = parentFilter;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/QueryShardException.java b/server/src/main/java/org/opensearch/index/query/QueryShardException.java
index 4b6c6d9aa8dd5..68a2501c501f3 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryShardException.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryShardException.java
@@ -33,15 +33,17 @@
 package org.opensearch.index.query;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Exception that is thrown when creating lucene queries on the shard
+ *
+ * @opensearch.internal
  */
 public class QueryShardException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/index/query/QueryStringQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/QueryStringQueryBuilder.java
index 7d893f54ea64c..469dc51da323a 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryStringQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryStringQueryBuilder.java
@@ -36,16 +36,16 @@
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.automaton.Operations;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.query.support.QueryParsers;
 import org.opensearch.index.search.QueryParserHelper;
@@ -66,6 +66,8 @@
  * will use the {@link #defaultField(String)} set. The second, when one or more fields are added
  * (using {@link #field(String)}), will run the parsed query against the provided fields, and combine
  * them using Dismax.
+ *
+ * @opensearch.internal
  */
 public class QueryStringQueryBuilder extends AbstractQueryBuilder<QueryStringQueryBuilder> {
 
@@ -77,6 +79,7 @@ public class QueryStringQueryBuilder extends AbstractQueryBuilder<QueryStringQue
     public static final int DEFAULT_FUZZY_PREFIX_LENGTH = FuzzyQuery.defaultPrefixLength;
     public static final int DEFAULT_FUZZY_MAX_EXPANSIONS = FuzzyQuery.defaultMaxExpansions;
     public static final int DEFAULT_PHRASE_SLOP = 0;
+    /** Default maximum edit distance. Defaults to AUTO. */
     public static final Fuzziness DEFAULT_FUZZINESS = Fuzziness.AUTO;
     public static final Operator DEFAULT_OPERATOR = Operator.OR;
     public static final MultiMatchQueryBuilder.Type DEFAULT_TYPE = MultiMatchQueryBuilder.Type.BEST_FIELDS;
@@ -414,7 +417,7 @@ public boolean enablePositionIncrements() {
      * Set the edit distance for fuzzy queries. Default is "AUTO".
      */
     public QueryStringQueryBuilder fuzziness(Fuzziness fuzziness) {
-        this.fuzziness = fuzziness == null ? DEFAULT_FUZZINESS : fuzziness;
+        this.fuzziness = fuzziness;
         return this;
     }
 
diff --git a/server/src/main/java/org/opensearch/index/query/QueryValidationException.java b/server/src/main/java/org/opensearch/index/query/QueryValidationException.java
index 8582ccbde4709..06680cabee0cd 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryValidationException.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryValidationException.java
@@ -38,6 +38,8 @@
 
 /**
  * This exception can be used to indicate various reasons why validation of a query has failed.
+ *
+ * @opensearch.internal
  */
 public class QueryValidationException extends ValidationException {
 
diff --git a/server/src/main/java/org/opensearch/index/query/RangeQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/RangeQueryBuilder.java
index 80b792d750546..0d54373112904 100644
--- a/server/src/main/java/org/opensearch/index/query/RangeQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/RangeQueryBuilder.java
@@ -35,16 +35,16 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.ShapeRelation;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateMathParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 
@@ -55,6 +55,8 @@
 
 /**
  * A Query that matches documents within an range of terms.
+ *
+ * @opensearch.internal
  */
 public class RangeQueryBuilder extends AbstractQueryBuilder<RangeQueryBuilder> implements MultiTermQueryBuilder {
     public static final String NAME = "range";
diff --git a/server/src/main/java/org/opensearch/index/query/RegexpFlag.java b/server/src/main/java/org/opensearch/index/query/RegexpFlag.java
index b1ee70a22bb17..b7e7569f67127 100644
--- a/server/src/main/java/org/opensearch/index/query/RegexpFlag.java
+++ b/server/src/main/java/org/opensearch/index/query/RegexpFlag.java
@@ -32,7 +32,7 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.util.automaton.RegExp;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 
 import java.util.Locale;
 
@@ -50,6 +50,8 @@
  *
  * @see RegexpQueryBuilder#flags(RegexpFlag...)
  * @see RegexpQueryBuilder#flags(RegexpFlag...)
+ *
+ * @opensearch.internal
  */
 public enum RegexpFlag {
 
diff --git a/server/src/main/java/org/opensearch/index/query/RegexpQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/RegexpQueryBuilder.java
index dc6546a3fd3a2..c7517dee143bb 100644
--- a/server/src/main/java/org/opensearch/index/query/RegexpQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/RegexpQueryBuilder.java
@@ -39,15 +39,15 @@
 import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.BytesRefs;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.support.QueryParsers;
@@ -57,6 +57,8 @@
 
 /**
  * A Query that does fuzzy matching for a specific value.
+ *
+ * @opensearch.internal
  */
 public class RegexpQueryBuilder extends AbstractQueryBuilder<RegexpQueryBuilder> implements MultiTermQueryBuilder {
     public static final String NAME = "regexp";
@@ -309,16 +311,17 @@ protected Query doToQuery(QueryShardContext context) throws QueryShardException,
             query = fieldType.regexpQuery(value, sanitisedSyntaxFlag, matchFlagsValue, maxDeterminizedStates, method, context);
         }
         if (query == null) {
-            RegexpQuery regexpQuery = new RegexpQuery(
+            if (method == null) {
+                method = MultiTermQuery.CONSTANT_SCORE_REWRITE;
+            }
+            query = new RegexpQuery(
                 new Term(fieldName, BytesRefs.toBytesRef(value)),
                 sanitisedSyntaxFlag,
                 matchFlagsValue,
-                maxDeterminizedStates
+                RegexpQuery.DEFAULT_PROVIDER,
+                maxDeterminizedStates,
+                method
             );
-            if (method != null) {
-                regexpQuery.setRewriteMethod(method);
-            }
-            query = regexpQuery;
         }
         return query;
     }
diff --git a/server/src/main/java/org/opensearch/index/query/Rewriteable.java b/server/src/main/java/org/opensearch/index/query/Rewriteable.java
index 826c6e71796c6..3ed779b52debf 100644
--- a/server/src/main/java/org/opensearch/index/query/Rewriteable.java
+++ b/server/src/main/java/org/opensearch/index/query/Rewriteable.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.ParsingException;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -40,6 +40,8 @@
 
 /**
  * A basic interface for rewriteable classes.
+ *
+ * @opensearch.internal
  */
 public interface Rewriteable<T> {
 
diff --git a/server/src/main/java/org/opensearch/index/query/ScriptQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/ScriptQueryBuilder.java
index 1d781060dc6bc..ded6fd0528c33 100644
--- a/server/src/main/java/org/opensearch/index/query/ScriptQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/ScriptQueryBuilder.java
@@ -45,12 +45,12 @@
 import org.apache.lucene.search.Weight;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.Functions;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.FilterScript;
 import org.opensearch.script.Script;
 
@@ -59,6 +59,11 @@
 
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
+/**
+ * Query builder for script queries
+ *
+ * @opensearch.internal
+ */
 public class ScriptQueryBuilder extends AbstractQueryBuilder<ScriptQueryBuilder> {
     public static final String NAME = "script";
 
@@ -159,6 +164,11 @@ protected Query doToQuery(QueryShardContext context) throws IOException {
         return new ScriptQuery(script, filterScript, queryName);
     }
 
+    /**
+     * Internal script query
+     *
+     * @opensearch.internal
+     */
     static class ScriptQuery extends Query {
 
         final Script script;
diff --git a/server/src/main/java/org/opensearch/index/query/SearchIndexNameMatcher.java b/server/src/main/java/org/opensearch/index/query/SearchIndexNameMatcher.java
index 8d4d06d65c412..00758309fc0f0 100644
--- a/server/src/main/java/org/opensearch/index/query/SearchIndexNameMatcher.java
+++ b/server/src/main/java/org/opensearch/index/query/SearchIndexNameMatcher.java
@@ -42,6 +42,8 @@
 
 /**
  * A predicate that checks whether an index pattern matches the current search shard target.
+ *
+ * @opensearch.internal
  */
 public class SearchIndexNameMatcher implements Predicate<String> {
     private final String indexName;
diff --git a/server/src/main/java/org/opensearch/index/query/SimpleQueryStringBuilder.java b/server/src/main/java/org/opensearch/index/query/SimpleQueryStringBuilder.java
index 0de30e42eb4d0..3cd0554af49a4 100644
--- a/server/src/main/java/org/opensearch/index/query/SimpleQueryStringBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SimpleQueryStringBuilder.java
@@ -35,15 +35,15 @@
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.search.QueryParserHelper;
 import org.opensearch.index.search.SimpleQueryStringQueryParser;
 import org.opensearch.index.search.SimpleQueryStringQueryParser.Settings;
@@ -86,6 +86,7 @@
  * {@code fields} - fields to search, defaults to _all if not set, allows
  * boosting a field with ^n
  *
+ * @opensearch.internal
  */
 public class SimpleQueryStringBuilder extends AbstractQueryBuilder<SimpleQueryStringBuilder> {
 
diff --git a/server/src/main/java/org/opensearch/index/query/SimpleQueryStringFlag.java b/server/src/main/java/org/opensearch/index/query/SimpleQueryStringFlag.java
index d6dc6cc1e4462..c989c52ca62b9 100644
--- a/server/src/main/java/org/opensearch/index/query/SimpleQueryStringFlag.java
+++ b/server/src/main/java/org/opensearch/index/query/SimpleQueryStringFlag.java
@@ -31,13 +31,15 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.search.SimpleQueryStringQueryParser;
 
 import java.util.Locale;
 
 /**
  * Flags for the XSimpleQueryString parser
+ *
+ * @opensearch.internal
  */
 public enum SimpleQueryStringFlag {
     ALL(-1),
@@ -66,7 +68,7 @@ public int value() {
     }
 
     static int resolveFlags(String flags) {
-        if (!Strings.hasLength(flags)) {
+        if (Strings.hasLength(flags) == false) {
             return ALL.value();
         }
         int magic = NONE.value();
diff --git a/server/src/main/java/org/opensearch/index/query/SpanContainingQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanContainingQueryBuilder.java
index 9168f7a29f2dc..32a19ea3e9b50 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanContainingQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanContainingQueryBuilder.java
@@ -34,13 +34,14 @@
 
 import org.apache.lucene.queries.spans.SpanContainingQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +50,8 @@
 
 /**
  * Builder for {@link org.apache.lucene.queries.spans.SpanContainingQuery}.
+ *
+ * @opensearch.internal
  */
 public class SpanContainingQueryBuilder extends AbstractQueryBuilder<SpanContainingQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_containing";
@@ -186,4 +189,11 @@ protected boolean doEquals(SpanContainingQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(big);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(little);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/SpanFirstQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanFirstQueryBuilder.java
index e3d6315b5d18c..bcbc64ddf386d 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanFirstQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanFirstQueryBuilder.java
@@ -34,19 +34,25 @@
 
 import org.apache.lucene.queries.spans.SpanFirstQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
 import static org.opensearch.index.query.SpanQueryBuilder.SpanQueryBuilderUtil.checkNoBoost;
 
+/**
+ * Query builder for span_first queries
+ *
+ * @opensearch.internal
+ */
 public class SpanFirstQueryBuilder extends AbstractQueryBuilder<SpanFirstQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_first";
 
@@ -181,4 +187,10 @@ protected boolean doEquals(SpanFirstQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(matchBuilder);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/SpanMultiTermQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanMultiTermQueryBuilder.java
index 9411ba9c59087..96d03c91964e3 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanMultiTermQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanMultiTermQueryBuilder.java
@@ -33,20 +33,21 @@
 
 import org.apache.lucene.queries.SpanMatchNoDocsQuery;
 import org.apache.lucene.queries.spans.SpanMultiTermQueryWrapper;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TopTermsRewrite;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.SpanBooleanQueryRewriteWithMaxClause;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.support.QueryParsers;
 
@@ -56,6 +57,8 @@
 /**
  * Query that allows wrapping a {@link MultiTermQueryBuilder} (one of wildcard, fuzzy, prefix, term, range or regexp query)
  * as a {@link SpanQueryBuilder} so it can be nested.
+ *
+ * @opensearch.internal
  */
 public class SpanMultiTermQueryBuilder extends AbstractQueryBuilder<SpanMultiTermQueryBuilder> implements SpanQueryBuilder {
 
@@ -211,4 +214,12 @@ protected boolean doEquals(SpanMultiTermQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (multiTermQueryBuilder != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(multiTermQueryBuilder);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/SpanNearQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanNearQueryBuilder.java
index a648eedc9f3b5..30a1c29c29126 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanNearQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanNearQueryBuilder.java
@@ -34,15 +34,17 @@
 
 import org.apache.lucene.queries.spans.SpanNearQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
@@ -57,6 +59,8 @@
  * Matches spans which are near one another. One can specify slop, the maximum number
  * of intervening unmatched positions, as well as whether matches are required to be in-order.
  * The span near query maps to Lucene {@link SpanNearQuery}.
+ *
+ * @opensearch.internal
  */
 public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_near";
@@ -296,6 +300,17 @@ public String getWriteableName() {
         return NAME;
     }
 
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (this.clauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(BooleanClause.Occur.MUST);
+            for (QueryBuilder subQb : this.clauses) {
+                subVisitor.accept(subQb);
+            }
+        }
+    }
+
     /**
      * SpanGapQueryBuilder enables gaps in a SpanNearQuery.
      * Since, SpanGapQuery is private to SpanNearQuery, SpanGapQueryBuilder cannot
@@ -304,6 +319,8 @@ public String getWriteableName() {
      * can be invoked for it.
      * This QueryBuilder is only applicable as a clause in SpanGapQueryBuilder but
      * yet to enforce this restriction.
+     *
+     * @opensearch.internal
      */
     public static class SpanGapQueryBuilder implements SpanQueryBuilder {
         public static final String NAME = "span_gap";
@@ -440,7 +457,7 @@ public final int hashCode() {
 
         @Override
         public final String toString() {
-            return Strings.toString(this, true, true);
+            return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
         }
 
         // copied from AbstractQueryBuilder
diff --git a/server/src/main/java/org/opensearch/index/query/SpanNotQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanNotQueryBuilder.java
index c43430e00de98..59ec5b9d77fc8 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanNotQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanNotQueryBuilder.java
@@ -34,19 +34,25 @@
 
 import org.apache.lucene.queries.spans.SpanNotQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
 import static org.opensearch.index.query.SpanQueryBuilder.SpanQueryBuilderUtil.checkNoBoost;
 
+/**
+ * Query builder for span_not queries
+ *
+ * @opensearch.internal
+ */
 public class SpanNotQueryBuilder extends AbstractQueryBuilder<SpanNotQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_not";
 
@@ -279,4 +285,16 @@ protected boolean doEquals(SpanNotQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (include != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(include);
+        }
+
+        if (exclude != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.MUST_NOT).accept(exclude);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/SpanOrQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanOrQueryBuilder.java
index 0a08f778cf889..fae1e318c66bd 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanOrQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanOrQueryBuilder.java
@@ -34,13 +34,14 @@
 
 import org.apache.lucene.queries.spans.SpanOrQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -52,6 +53,8 @@
 
 /**
  * Span query that matches the union of its clauses. Maps to {@link SpanOrQuery}.
+ *
+ * @opensearch.internal
  */
 public class SpanOrQueryBuilder extends AbstractQueryBuilder<SpanOrQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_or";
@@ -186,4 +189,15 @@ protected boolean doEquals(SpanOrQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (clauses.isEmpty() == false) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(BooleanClause.Occur.SHOULD);
+            for (QueryBuilder subQb : this.clauses) {
+                subVisitor.accept(subQb);
+            }
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/SpanQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanQueryBuilder.java
index ba2adadc7a77c..d785cb253ece8 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanQueryBuilder.java
@@ -32,14 +32,21 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 
 /**
  * Marker interface for a specific type of {@link QueryBuilder} that allows to build span queries.
+ *
+ * @opensearch.internal
  */
 public interface SpanQueryBuilder extends QueryBuilder {
 
+    /**
+     * Utility for span query builders
+     *
+     * @opensearch.internal
+     */
     class SpanQueryBuilderUtil {
         private SpanQueryBuilderUtil() {
             // utility class
diff --git a/server/src/main/java/org/opensearch/index/query/SpanTermQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanTermQueryBuilder.java
index 02a0f55685ca4..a6108578da06c 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanTermQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanTermQueryBuilder.java
@@ -36,11 +36,11 @@
 import org.apache.lucene.queries.spans.SpanQuery;
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
@@ -48,6 +48,8 @@
 /**
  * A Span Query that matches documents containing a term.
  * @see SpanTermQuery
+ *
+ * @opensearch.internal
  */
 public class SpanTermQueryBuilder extends BaseTermQueryBuilder<SpanTermQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_term";
diff --git a/server/src/main/java/org/opensearch/index/query/SpanWithinQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/SpanWithinQueryBuilder.java
index a8ab2a8831f55..4d5a6dde61a70 100644
--- a/server/src/main/java/org/opensearch/index/query/SpanWithinQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/SpanWithinQueryBuilder.java
@@ -34,13 +34,14 @@
 
 import org.apache.lucene.queries.spans.SpanQuery;
 import org.apache.lucene.queries.spans.SpanWithinQuery;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +50,8 @@
 
 /**
  * Builder for {@link org.apache.lucene.queries.spans.SpanWithinQuery}.
+ *
+ * @opensearch.internal
  */
 public class SpanWithinQueryBuilder extends AbstractQueryBuilder<SpanWithinQueryBuilder> implements SpanQueryBuilder {
     public static final String NAME = "span_within";
@@ -195,4 +198,11 @@ protected boolean doEquals(SpanWithinQueryBuilder other) {
     public String getWriteableName() {
         return NAME;
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(big);
+        visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(little);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/TermQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/TermQueryBuilder.java
index a600e8284e395..8a834395e2e2d 100644
--- a/server/src/main/java/org/opensearch/index/query/TermQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/TermQueryBuilder.java
@@ -36,20 +36,22 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ConstantFieldType;
+import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * A Query that matches documents containing a term.
+ *
+ * @opensearch.internal
  */
 public class TermQueryBuilder extends BaseTermQueryBuilder<TermQueryBuilder> {
     public static final String NAME = "term";
diff --git a/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
index ac29cb2cf5201..ac0ca3919ea38 100644
--- a/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
@@ -37,19 +37,19 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.client.Client;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ConstantFieldType;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -71,6 +71,8 @@
 
 /**
  * A filter for a field based on several terms matching on any of them.
+ *
+ * @opensearch.internal
  */
 public class TermsQueryBuilder extends AbstractQueryBuilder<TermsQueryBuilder> {
     public static final String NAME = "terms";
diff --git a/server/src/main/java/org/opensearch/index/query/TermsSetQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/TermsSetQueryBuilder.java
index f7dd146f9f019..e2cf7384ecac7 100644
--- a/server/src/main/java/org/opensearch/index/query/TermsSetQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/TermsSetQueryBuilder.java
@@ -42,14 +42,14 @@
 import org.apache.lucene.search.LongValuesSource;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.BytesRefs;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.script.Script;
@@ -62,6 +62,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Query builder for terms_set queries
+ *
+ * @opensearch.internal
+ */
 public final class TermsSetQueryBuilder extends AbstractQueryBuilder<TermsSetQueryBuilder> {
 
     public static final String NAME = "terms_set";
@@ -293,6 +298,11 @@ private LongValuesSource createValuesSource(QueryShardContext context) {
         return longValuesSource;
     }
 
+    /**
+     * Values Source for scripted long values
+     *
+     * @opensearch.internal
+     */
     static final class ScriptLongValueSource extends LongValuesSource {
 
         private final Script script;
@@ -361,8 +371,12 @@ public LongValuesSource rewrite(IndexSearcher searcher) throws IOException {
 
     }
 
-    // Forked from LongValuesSource.FieldValuesSource and changed getValues() method to always use sorted numeric
-    // doc values, because that is what is being used in NumberFieldMapper.
+    /**
+     * Forked from LongValuesSource.FieldValuesSource and changed getValues() method to always use sorted numeric
+     * doc values, because that is what is being used in NumberFieldMapper.
+     *
+     * @opensearch.internal
+     */
     static class FieldValuesSource extends LongValuesSource {
 
         private final String fieldName;
diff --git a/server/src/main/java/org/opensearch/index/query/VectorGeoPointShapeQueryProcessor.java b/server/src/main/java/org/opensearch/index/query/VectorGeoPointShapeQueryProcessor.java
index 08ba3dc1fe8fa..eb7923a5b5212 100644
--- a/server/src/main/java/org/opensearch/index/query/VectorGeoPointShapeQueryProcessor.java
+++ b/server/src/main/java/org/opensearch/index/query/VectorGeoPointShapeQueryProcessor.java
@@ -59,6 +59,11 @@
 
 import java.util.ArrayList;
 
+/**
+ * Query processor for lucene 6 LatLonPoint queries
+ *
+ * @opensearch.internal
+ */
 public class VectorGeoPointShapeQueryProcessor {
 
     public Query geoShapeQuery(Geometry shape, String fieldName, ShapeRelation relation, QueryShardContext context) {
diff --git a/server/src/main/java/org/opensearch/index/query/VectorGeoShapeQueryProcessor.java b/server/src/main/java/org/opensearch/index/query/VectorGeoShapeQueryProcessor.java
index 16a2968a2e7b2..e11b22e9296cf 100644
--- a/server/src/main/java/org/opensearch/index/query/VectorGeoShapeQueryProcessor.java
+++ b/server/src/main/java/org/opensearch/index/query/VectorGeoShapeQueryProcessor.java
@@ -58,6 +58,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Query processor for Lucene 6 LatLonShape queries
+ *
+ * @opensearch.internal
+ */
 public class VectorGeoShapeQueryProcessor {
 
     public Query geoShapeQuery(Geometry shape, String fieldName, ShapeRelation relation, QueryShardContext context) {
@@ -83,6 +88,11 @@ private Query getVectorQueryFromShape(Geometry queryShape, String fieldName, Sha
         );
     }
 
+    /**
+     * Geometry collector for LatLonShape indexing types
+     *
+     * @opensearch.internal
+     */
     private static class LuceneGeometryCollector implements GeometryVisitor<Void, RuntimeException> {
         private final List<LatLonGeometry> geometries = new ArrayList<>();
         private final String name;
diff --git a/server/src/main/java/org/opensearch/index/query/WildcardQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/WildcardQueryBuilder.java
index 9dab290b8bd3e..2521fcd84f56c 100644
--- a/server/src/main/java/org/opensearch/index/query/WildcardQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/WildcardQueryBuilder.java
@@ -37,16 +37,16 @@
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ConstantFieldType;
+import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.support.QueryParsers;
 
 import java.io.IOException;
@@ -59,6 +59,8 @@
  * needs to iterate over many terms. In order to prevent extremely slow WildcardQueries,
  * a Wildcard term should not start with one of the wildcards {@code *} or
  * {@code ?}.
+ *
+ * @opensearch.internal
  */
 public class WildcardQueryBuilder extends AbstractQueryBuilder<WildcardQueryBuilder> implements MultiTermQueryBuilder {
     public static final String NAME = "wildcard";
diff --git a/server/src/main/java/org/opensearch/index/query/WrapperQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/WrapperQueryBuilder.java
index 81c8e14f50912..8a322b2f9e173 100644
--- a/server/src/main/java/org/opensearch/index/query/WrapperQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/WrapperQueryBuilder.java
@@ -34,16 +34,16 @@
 
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -62,6 +62,8 @@
  *      bool.must(new TermQueryBuilder("field2","value2"));
  * </code>
  * </pre>
+ *
+ * @opensearch.internal
  */
 public class WrapperQueryBuilder extends AbstractQueryBuilder<WrapperQueryBuilder> {
     public static final String NAME = "wrapper";
@@ -173,7 +175,8 @@ protected boolean doEquals(WrapperQueryBuilder other) {
     @Override
     protected QueryBuilder doRewrite(QueryRewriteContext context) throws IOException {
         try (
-            XContentParser qSourceParser = XContentFactory.xContent(source)
+            XContentParser qSourceParser = MediaTypeRegistry.xContent(source)
+                .xContent()
                 .createParser(context.getXContentRegistry(), LoggingDeprecationHandler.INSTANCE, source)
         ) {
 
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunction.java b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunction.java
index 02d01ef470b61..5d0e05c1cdf30 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunction.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunction.java
@@ -41,6 +41,7 @@
  * function or something of the kind. This is used, for example, by
  * {@link GaussDecayFunctionBuilder}.
  *
+ * @opensearch.internal
  */
 public interface DecayFunction {
 
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionBuilder.java
index 0ee61b34cd279..cfc44d4434d3b 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionBuilder.java
@@ -36,24 +36,24 @@
 import org.apache.lucene.search.Explanation;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.LeafScoreFunction;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexGeoPointFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
@@ -72,6 +72,11 @@
 import java.io.InputStream;
 import java.util.Objects;
 
+/**
+ * Foundation builder for a decay function
+ *
+ * @opensearch.internal
+ */
 public abstract class DecayFunctionBuilder<DFB extends DecayFunctionBuilder<DFB>> extends ScoreFunctionBuilder<DFB> {
 
     protected static final String ORIGIN = "origin";
@@ -225,7 +230,8 @@ protected ScoreFunction doToFunction(QueryShardContext context) throws IOExcepti
         // EMPTY is safe because parseVariable doesn't use namedObject
         try (
             InputStream stream = functionBytes.streamInput();
-            XContentParser parser = XContentFactory.xContent(XContentHelper.xContentType(functionBytes))
+            XContentParser parser = MediaTypeRegistry.xContentType(functionBytes)
+                .xContent()
                 .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
         ) {
             scoreFunction = parseVariable(fieldName, parser, context, multiValueMode);
@@ -419,6 +425,11 @@ private AbstractDistanceScoreFunction parseDateVariable(
         );
     }
 
+    /**
+     * Score function for geo field data
+     *
+     * @opensearch.internal
+     */
     static class GeoFieldDataScoreFunction extends AbstractDistanceScoreFunction {
 
         private final GeoPoint origin;
@@ -515,6 +526,11 @@ protected int doHashCode() {
         }
     }
 
+    /**
+     * Score function for numeric data
+     *
+     * @opensearch.internal
+     */
     static class NumericFieldDataScoreFunction extends AbstractDistanceScoreFunction {
 
         private final IndexNumericFieldData fieldData;
@@ -605,7 +621,8 @@ protected boolean doEquals(ScoreFunction other) {
     /**
      * This is the base class for scoring a single field.
      *
-     * */
+     * @opensearch.internal
+     */
     public abstract static class AbstractDistanceScoreFunction extends ScoreFunction {
 
         private final double scale;
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionParser.java b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionParser.java
index c4ae707ba9212..f04d5c46740f7 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionParser.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/DecayFunctionParser.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.query.functionscore;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.SearchModule;
@@ -79,6 +79,8 @@
  * {@link DecayFunctionBuilder}, setup a PARSER field with this class, and
  * register them in {@link SearchModule#registerScoreFunctions} or {@link SearchPlugin#getScoreFunctions}
  * See {@link GaussDecayFunctionBuilder#PARSER} for an example.
+ *
+ * @opensearch.internal
  */
 public final class DecayFunctionParser<DFB extends DecayFunctionBuilder<DFB>> implements ScoreFunctionParser<DFB> {
 
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ExponentialDecayFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/ExponentialDecayFunctionBuilder.java
index b78e75762fe11..7c69e345eb307 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ExponentialDecayFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ExponentialDecayFunctionBuilder.java
@@ -34,12 +34,17 @@
 
 import org.apache.lucene.search.Explanation;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.Functions;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Foundation builder for an exponential decay
+ *
+ * @opensearch.internal
+ */
 public class ExponentialDecayFunctionBuilder extends DecayFunctionBuilder<ExponentialDecayFunctionBuilder> {
     public static final String NAME = "exp";
     public static final ScoreFunctionParser<ExponentialDecayFunctionBuilder> PARSER = new DecayFunctionParser<>(
@@ -91,6 +96,11 @@ public DecayFunction getDecayFunction() {
         return EXP_DECAY_FUNCTION;
     }
 
+    /**
+     * Exponential decay
+     *
+     * @opensearch.internal
+     */
     private static final class ExponentialDecayScoreFunction implements DecayFunction {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionBuilder.java
index 39f12409267ab..28498735cb5a4 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionBuilder.java
@@ -34,13 +34,13 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
@@ -52,6 +52,8 @@
 /**
  * Builder to construct {@code field_value_factor} functions for a function
  * score query.
+ *
+ * @opensearch.internal
  */
 public class FieldValueFactorFunctionBuilder extends ScoreFunctionBuilder<FieldValueFactorFunctionBuilder> {
     public static final String NAME = "field_value_factor";
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilder.java
index f9484e6c94ea7..139d28cb6a7df 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilder.java
@@ -35,18 +35,18 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.InnerHitContextBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
@@ -66,6 +66,8 @@
 /**
  * A query that uses a filters with a script associated with them to compute the
  * score.
+ *
+ * @opensearch.internal
  */
 public class FunctionScoreQueryBuilder extends AbstractQueryBuilder<FunctionScoreQueryBuilder> {
     public static final String NAME = "function_score";
@@ -369,6 +371,8 @@ protected Query doToQuery(QueryShardContext context) throws IOException {
     /**
      * Function to be associated with an optional filter, meaning it will be executed only for the documents
      * that match the given filter.
+     *
+     * @opensearch.internal
      */
     public static class FilterFunctionBuilder implements ToXContentObject, Writeable {
         private final QueryBuilder filter;
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/GaussDecayFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/GaussDecayFunctionBuilder.java
index ac6ae33cb4ed0..89bf383ed85dc 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/GaussDecayFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/GaussDecayFunctionBuilder.java
@@ -34,13 +34,18 @@
 
 import org.apache.lucene.search.Explanation;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.Functions;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Foundation builder for a gaussian decay
+ *
+ * @opensearch.internal
+ */
 public class GaussDecayFunctionBuilder extends DecayFunctionBuilder<GaussDecayFunctionBuilder> {
     public static final String NAME = "gauss";
     public static final ParseField FUNCTION_NAME_FIELD = new ParseField(NAME);
@@ -91,6 +96,11 @@ public DecayFunction getDecayFunction() {
         return GAUSS_DECAY_FUNCTION;
     }
 
+    /**
+     * Gaussian scoring
+     *
+     * @opensearch.internal
+     */
     private static final class GaussScoreFunction implements DecayFunction {
         @Override
         public double evaluate(double value, double scale) {
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/LinearDecayFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/LinearDecayFunctionBuilder.java
index 03102e45a41ba..9205c658c0415 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/LinearDecayFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/LinearDecayFunctionBuilder.java
@@ -34,12 +34,17 @@
 
 import org.apache.lucene.search.Explanation;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.Functions;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Foundation builder for a linear decay
+ *
+ * @opensearch.internal
+ */
 public class LinearDecayFunctionBuilder extends DecayFunctionBuilder<LinearDecayFunctionBuilder> {
     public static final String NAME = "linear";
     public static final ScoreFunctionParser<LinearDecayFunctionBuilder> PARSER = new DecayFunctionParser<>(LinearDecayFunctionBuilder::new);
@@ -89,6 +94,11 @@ public DecayFunction getDecayFunction() {
         return LINEAR_DECAY_FUNCTION;
     }
 
+    /**
+     * Linear decay
+     *
+     * @opensearch.internal
+     */
     private static final class LinearDecayScoreFunction implements DecayFunction {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/RandomScoreFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/RandomScoreFunctionBuilder.java
index 26495c93082ae..1726c44674d66 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/RandomScoreFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/RandomScoreFunctionBuilder.java
@@ -32,14 +32,14 @@
 package org.opensearch.index.query.functionscore;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.lucene.search.function.RandomScoreFunction;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
@@ -49,6 +49,8 @@
 
 /**
  * A function that computes a random score for the matched documents
+ *
+ * @opensearch.internal
  */
 public class RandomScoreFunctionBuilder extends ScoreFunctionBuilder<RandomScoreFunctionBuilder> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RandomScoreFunctionBuilder.class);
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilder.java
index 4987f260bc9b4..249c970777ab9 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilder.java
@@ -33,18 +33,23 @@
 package org.opensearch.index.query.functionscore;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
 import org.opensearch.common.lucene.search.function.WeightFactorFunction;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Foundation builder for a score function
+ *
+ * @opensearch.internal
+ */
 public abstract class ScoreFunctionBuilder<FB extends ScoreFunctionBuilder<FB>> implements ToXContentFragment, NamedWriteable {
 
     private Float weight;
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilders.java b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilders.java
index 59d02e9381d7e..db35752cd5ee7 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilders.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilders.java
@@ -40,6 +40,8 @@
 
 /**
  * Static method aliases for constructors of known {@link ScoreFunctionBuilder}s.
+ *
+ * @opensearch.internal
  */
 public class ScoreFunctionBuilders {
 
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionParser.java b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionParser.java
index e5720b94e71fa..80a9809e326f1 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionParser.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ScoreFunctionParser.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.index.query.functionscore;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 /**
  * Parses XContent into a {@link ScoreFunctionBuilder}.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface ScoreFunctionParser<FB extends ScoreFunctionBuilder<FB>> {
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreFunctionBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreFunctionBuilder.java
index 2701e5867edde..3dadaeada2e60 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreFunctionBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreFunctionBuilder.java
@@ -33,13 +33,13 @@
 package org.opensearch.index.query.functionscore;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
 import org.opensearch.common.lucene.search.function.ScriptScoreFunction;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.script.ScoreScript;
@@ -51,6 +51,8 @@
 /**
  * A function that uses a script to compute or influence the score of documents
  * that match with the inner query or filter.
+ *
+ * @opensearch.internal
  */
 public class ScriptScoreFunctionBuilder extends ScoreFunctionBuilder<ScriptScoreFunctionBuilder> {
     public static final String NAME = "script_score";
@@ -112,7 +114,7 @@ protected int doHashCode() {
     protected ScoreFunction doToFunction(QueryShardContext context) {
         try {
             ScoreScript.Factory factory = context.compile(script, ScoreScript.CONTEXT);
-            ScoreScript.LeafFactory searchScript = factory.newFactory(script.getParams(), context.lookup());
+            ScoreScript.LeafFactory searchScript = factory.newFactory(script.getParams(), context.lookup(), context.searcher());
             return new ScriptScoreFunction(
                 script,
                 searchScript,
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreQueryBuilder.java
index e2a1f2fb1f5aa..9d28d81f732df 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/ScriptScoreQueryBuilder.java
@@ -32,20 +32,22 @@
 
 package org.opensearch.index.query.functionscore;
 
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.Query;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.ScriptScoreQuery;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.InnerHitContextBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.QueryBuilderVisitor;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.ScoreScript;
@@ -55,12 +57,14 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
 /**
  * A query that computes a document score based on the provided script
+ *
+ * @opensearch.internal
  */
 public class ScriptScoreQueryBuilder extends AbstractQueryBuilder<ScriptScoreQueryBuilder> {
 
@@ -194,7 +198,7 @@ protected Query doToQuery(QueryShardContext context) throws IOException {
             );
         }
         ScoreScript.Factory factory = context.compile(script, ScoreScript.CONTEXT);
-        ScoreScript.LeafFactory scoreScriptFactory = factory.newFactory(script.getParams(), context.lookup());
+        ScoreScript.LeafFactory scoreScriptFactory = factory.newFactory(script.getParams(), context.lookup(), context.searcher());
         final QueryBuilder queryBuilder = this.query;
         Query query = queryBuilder.toQuery(context);
         return new ScriptScoreQuery(
@@ -231,4 +235,12 @@ protected void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> inner
         InnerHitContextBuilder.extractInnerHits(query(), innerHits);
     }
 
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (query != null) {
+            QueryBuilderVisitor subVisitor = visitor.getChildVisitor(BooleanClause.Occur.MUST);
+            subVisitor.accept(query);
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunction.java b/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunction.java
new file mode 100644
index 0000000000000..95fbecc53f4ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunction.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.query.functionscore;
+
+import java.io.IOException;
+
+/**
+ * An interface representing a term frequency function used to compute document scores
+ * based on specific term frequency calculations. Implementations of this interface should
+ * provide a way to execute the term frequency function for a given document ID.
+ *
+ * @opensearch.internal
+ */
+public interface TermFrequencyFunction {
+    Object execute(int docId) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunctionFactory.java b/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunctionFactory.java
new file mode 100644
index 0000000000000..9db58f0f78a30
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunctionFactory.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.query.functionscore;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.queries.function.FunctionValues;
+import org.apache.lucene.queries.function.valuesource.SumTotalTermFreqValueSource;
+import org.apache.lucene.queries.function.valuesource.TermFreqValueSource;
+import org.apache.lucene.queries.function.valuesource.TotalTermFreqValueSource;
+import org.apache.lucene.search.IndexSearcher;
+import org.opensearch.common.lucene.BytesRefs;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A factory class for creating instances of {@link TermFrequencyFunction}.
+ * This class provides methods for creating different term frequency functions based on
+ * the specified function name, field, and term. Each term frequency function is designed
+ * to compute document scores based on specific term frequency calculations.
+ *
+ * @opensearch.internal
+ */
+public class TermFrequencyFunctionFactory {
+    public static TermFrequencyFunction createFunction(
+        TermFrequencyFunctionName functionName,
+        String field,
+        String term,
+        LeafReaderContext readerContext,
+        IndexSearcher indexSearcher
+    ) throws IOException {
+        switch (functionName) {
+            case TERM_FREQ:
+                TermFreqValueSource termFreqValueSource = new TermFreqValueSource(field, term, field, BytesRefs.toBytesRef(term));
+                FunctionValues functionValues = termFreqValueSource.getValues(null, readerContext);
+                return docId -> functionValues.intVal(docId);
+            case TOTAL_TERM_FREQ:
+                TotalTermFreqValueSource totalTermFreqValueSource = new TotalTermFreqValueSource(
+                    field,
+                    term,
+                    field,
+                    BytesRefs.toBytesRef(term)
+                );
+                Map<Object, Object> ttfContext = new HashMap<>();
+                totalTermFreqValueSource.createWeight(ttfContext, indexSearcher);
+                functionValues = totalTermFreqValueSource.getValues(ttfContext, readerContext);
+                return docId -> functionValues.longVal(docId);
+            case SUM_TOTAL_TERM_FREQ:
+                SumTotalTermFreqValueSource sumTotalTermFreqValueSource = new SumTotalTermFreqValueSource(field);
+                Map<Object, Object> sttfContext = new HashMap<>();
+                sumTotalTermFreqValueSource.createWeight(sttfContext, indexSearcher);
+                functionValues = sumTotalTermFreqValueSource.getValues(sttfContext, readerContext);
+                return docId -> functionValues.longVal(docId);
+            default:
+                throw new IllegalArgumentException("Unsupported function: " + functionName);
+        }
+    }
+
+    /**
+     * An enumeration representing the names of supported term frequency functions.
+     */
+    public enum TermFrequencyFunctionName {
+        TERM_FREQ("termFreq"),
+        TOTAL_TERM_FREQ("totalTermFreq"),
+        SUM_TOTAL_TERM_FREQ("sumTotalTermFreq");
+
+        private final String termFrequencyFunctionName;
+
+        TermFrequencyFunctionName(String termFrequencyFunctionName) {
+            this.termFrequencyFunctionName = termFrequencyFunctionName;
+        }
+
+        public String getTermFrequencyFunctionName() {
+            return termFrequencyFunctionName;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/WeightBuilder.java b/server/src/main/java/org/opensearch/index/query/functionscore/WeightBuilder.java
index 333a6a3c6ee1c..254607edd44d2 100644
--- a/server/src/main/java/org/opensearch/index/query/functionscore/WeightBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/WeightBuilder.java
@@ -33,16 +33,18 @@
 package org.opensearch.index.query.functionscore;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 
 import java.io.IOException;
 
 /**
  * A query that multiplies the weight to the score.
+ *
+ * @opensearch.internal
  */
 public class WeightBuilder extends ScoreFunctionBuilder<WeightBuilder> {
     public static final String NAME = "weight";
diff --git a/server/src/main/java/org/opensearch/index/query/functionscore/package-info.java b/server/src/main/java/org/opensearch/index/query/functionscore/package-info.java
new file mode 100644
index 0000000000000..e590fd4a605d0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/functionscore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Foundation classes for implementing Function Scoring */
+package org.opensearch.index.query.functionscore;
diff --git a/server/src/main/java/org/opensearch/index/query/package-info.java b/server/src/main/java/org/opensearch/index/query/package-info.java
new file mode 100644
index 0000000000000..fe9ea6e4ba1b6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Query implementations  */
+package org.opensearch.index.query;
diff --git a/server/src/main/java/org/opensearch/index/query/support/NestedScope.java b/server/src/main/java/org/opensearch/index/query/support/NestedScope.java
index 150498191dfbe..4a09b11666c18 100644
--- a/server/src/main/java/org/opensearch/index/query/support/NestedScope.java
+++ b/server/src/main/java/org/opensearch/index/query/support/NestedScope.java
@@ -39,6 +39,8 @@
 
 /**
  * During query parsing this keeps track of the current nested level.
+ *
+ * @opensearch.internal
  */
 public final class NestedScope {
 
diff --git a/server/src/main/java/org/opensearch/index/query/support/QueryParsers.java b/server/src/main/java/org/opensearch/index/query/support/QueryParsers.java
index 851b334fc10b4..af8f7c7b4b8a7 100644
--- a/server/src/main/java/org/opensearch/index/query/support/QueryParsers.java
+++ b/server/src/main/java/org/opensearch/index/query/support/QueryParsers.java
@@ -34,9 +34,14 @@
 
 import org.apache.lucene.search.MultiTermQuery;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.DeprecationHandler;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.DeprecationHandler;
 
+/**
+ * Utility class for Query Parsers
+ *
+ * @opensearch.internal
+ */
 public final class QueryParsers {
 
     public static final ParseField CONSTANT_SCORE = new ParseField("constant_score");
diff --git a/server/src/main/java/org/opensearch/index/query/support/package-info.java b/server/src/main/java/org/opensearch/index/query/support/package-info.java
new file mode 100644
index 0000000000000..f14412c0fde3c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/query/support/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Support classes for OpenSearch Queries - todo remove this package? */
+package org.opensearch.index.query.support;
diff --git a/server/src/main/java/org/opensearch/index/recovery/RecoveryStats.java b/server/src/main/java/org/opensearch/index/recovery/RecoveryStats.java
index 4be13f3eacc5e..675f7c08c827c 100644
--- a/server/src/main/java/org/opensearch/index/recovery/RecoveryStats.java
+++ b/server/src/main/java/org/opensearch/index/recovery/RecoveryStats.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.index.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -45,6 +45,8 @@
 /**
  * Recovery related statistics, starting at the shard level and allowing aggregation to
  * indices and node level
+ *
+ * @opensearch.internal
  */
 public class RecoveryStats implements ToXContentFragment, Writeable {
 
@@ -125,6 +127,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for recovery statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String RECOVERY = "recovery";
         static final String CURRENT_AS_SOURCE = "current_as_source";
diff --git a/server/src/main/java/org/opensearch/index/recovery/RemoteStoreRestoreService.java b/server/src/main/java/org/opensearch/index/recovery/RemoteStoreRestoreService.java
new file mode 100644
index 0000000000000..94fd08b99ac58
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/recovery/RemoteStoreRestoreService.java
@@ -0,0 +1,345 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.recovery;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.Version;
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.block.ClusterBlocks;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.MetadataCreateIndexService;
+import org.opensearch.cluster.metadata.MetadataIndexUpgradeService;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.indices.ShardLimitValidator;
+import org.opensearch.repositories.IndexId;
+import org.opensearch.snapshots.RestoreInfo;
+import org.opensearch.snapshots.RestoreService;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+
+/**
+ * Service responsible for restoring index data from remote store
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreRestoreService {
+    private static final Logger logger = LogManager.getLogger(RemoteStoreRestoreService.class);
+
+    private final ClusterService clusterService;
+
+    private final AllocationService allocationService;
+
+    private final MetadataCreateIndexService createIndexService;
+
+    private final MetadataIndexUpgradeService metadataIndexUpgradeService;
+
+    private final ShardLimitValidator shardLimitValidator;
+
+    private final RemoteClusterStateService remoteClusterStateService;
+
+    public RemoteStoreRestoreService(
+        ClusterService clusterService,
+        AllocationService allocationService,
+        MetadataCreateIndexService createIndexService,
+        MetadataIndexUpgradeService metadataIndexUpgradeService,
+        ShardLimitValidator shardLimitValidator,
+        RemoteClusterStateService remoteClusterStateService
+    ) {
+        this.clusterService = clusterService;
+        this.allocationService = allocationService;
+        this.createIndexService = createIndexService;
+        this.metadataIndexUpgradeService = metadataIndexUpgradeService;
+        this.shardLimitValidator = shardLimitValidator;
+        this.remoteClusterStateService = remoteClusterStateService;
+    }
+
+    /**
+     * Restores data from remote store for indices specified in the restore request.
+     *
+     * @param request  restore request
+     * @param listener restore listener
+     */
+    public void restore(RestoreRemoteStoreRequest request, final ActionListener<RestoreService.RestoreCompletionResponse> listener) {
+        clusterService.submitStateUpdateTask("restore[remote_store]", new ClusterStateUpdateTask() {
+            String restoreUUID;
+            RestoreInfo restoreInfo = null;
+
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                RemoteRestoreResult remoteRestoreResult = restore(currentState, null, request.restoreAllShards(), request.indices());
+                restoreUUID = remoteRestoreResult.getRestoreUUID();
+                restoreInfo = remoteRestoreResult.getRestoreInfo();
+                return remoteRestoreResult.getClusterState();
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.warn("failed to restore from remote store", e);
+                listener.onFailure(e);
+            }
+
+            @Override
+            public TimeValue timeout() {
+                return request.clusterManagerNodeTimeout();
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                listener.onResponse(new RestoreService.RestoreCompletionResponse(restoreUUID, null, restoreInfo));
+            }
+        });
+    }
+
+    /**
+     * Executes remote restore
+     * @param currentState current cluster state
+     * @param restoreClusterUUID cluster UUID used to restore IndexMetadata
+     * @param restoreAllShards indicates if all shards of the index needs to be restored. This flag is ignored if remoteClusterUUID is provided
+     * @param indexNames list of indices to restore. This list is ignored if remoteClusterUUID is provided
+     * @return remote restore result
+     */
+    public RemoteRestoreResult restore(
+        ClusterState currentState,
+        @Nullable String restoreClusterUUID,
+        boolean restoreAllShards,
+        String[] indexNames
+    ) {
+        Map<String, Tuple<Boolean, IndexMetadata>> indexMetadataMap = new HashMap<>();
+        boolean metadataFromRemoteStore = (restoreClusterUUID == null
+            || restoreClusterUUID.isEmpty()
+            || restoreClusterUUID.isBlank()) == false;
+        if (metadataFromRemoteStore) {
+            try {
+                remoteClusterStateService.getLatestIndexMetadata(currentState.getClusterName().value(), restoreClusterUUID)
+                    .values()
+                    .forEach(indexMetadata -> {
+                        indexMetadataMap.put(indexMetadata.getIndex().getName(), new Tuple<>(true, indexMetadata));
+                    });
+            } catch (Exception e) {
+                throw new IllegalStateException("Unable to restore remote index metadata", e);
+            }
+        } else {
+            for (String indexName : indexNames) {
+                IndexMetadata indexMetadata = currentState.metadata().index(indexName);
+                if (indexMetadata == null) {
+                    logger.warn("Index restore is not supported for non-existent index. Skipping: {}", indexName);
+                } else {
+                    indexMetadataMap.put(indexName, new Tuple<>(false, indexMetadata));
+                }
+            }
+        }
+        validate(currentState, indexMetadataMap, restoreClusterUUID, restoreAllShards);
+        return executeRestore(currentState, indexMetadataMap, restoreAllShards);
+    }
+
+    /**
+     * Executes remote restore
+     * @param currentState current cluster state
+     * @param indexMetadataMap map of index metadata to restore
+     * @param restoreAllShards indicates if all shards of the index needs to be restored
+     * @return remote restore result
+     */
+    private RemoteRestoreResult executeRestore(
+        ClusterState currentState,
+        Map<String, Tuple<Boolean, IndexMetadata>> indexMetadataMap,
+        boolean restoreAllShards
+    ) {
+        final String restoreUUID = UUIDs.randomBase64UUID();
+        List<String> indicesToBeRestored = new ArrayList<>();
+        int totalShards = 0;
+        ClusterState.Builder builder = ClusterState.builder(currentState);
+        Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
+        ClusterBlocks.Builder blocks = ClusterBlocks.builder().blocks(currentState.blocks());
+        RoutingTable.Builder rtBuilder = RoutingTable.builder(currentState.routingTable());
+        for (Map.Entry<String, Tuple<Boolean, IndexMetadata>> indexMetadataEntry : indexMetadataMap.entrySet()) {
+            String indexName = indexMetadataEntry.getKey();
+            IndexMetadata indexMetadata = indexMetadataEntry.getValue().v2();
+            boolean metadataFromRemoteStore = indexMetadataEntry.getValue().v1();
+            IndexMetadata updatedIndexMetadata = indexMetadata;
+            if (metadataFromRemoteStore == false && restoreAllShards) {
+                updatedIndexMetadata = IndexMetadata.builder(indexMetadata)
+                    .state(IndexMetadata.State.OPEN)
+                    .version(1 + indexMetadata.getVersion())
+                    .mappingVersion(1 + indexMetadata.getMappingVersion())
+                    .settingsVersion(1 + indexMetadata.getSettingsVersion())
+                    .aliasesVersion(1 + indexMetadata.getAliasesVersion())
+                    .build();
+            }
+
+            IndexId indexId = new IndexId(indexName, updatedIndexMetadata.getIndexUUID());
+
+            Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap = new HashMap<>();
+            if (metadataFromRemoteStore == false) {
+                indexShardRoutingTableMap = currentState.routingTable()
+                    .index(indexName)
+                    .shards()
+                    .values()
+                    .stream()
+                    .collect(Collectors.toMap(IndexShardRoutingTable::shardId, Function.identity()));
+            }
+
+            RecoverySource.RemoteStoreRecoverySource recoverySource = new RecoverySource.RemoteStoreRecoverySource(
+                restoreUUID,
+                updatedIndexMetadata.getCreationVersion(),
+                indexId
+            );
+            rtBuilder.addAsRemoteStoreRestore(
+                updatedIndexMetadata,
+                recoverySource,
+                indexShardRoutingTableMap,
+                restoreAllShards || metadataFromRemoteStore
+            );
+            blocks.updateBlocks(updatedIndexMetadata);
+            mdBuilder.put(updatedIndexMetadata, true);
+            indicesToBeRestored.add(indexName);
+            totalShards += updatedIndexMetadata.getNumberOfShards();
+        }
+
+        RestoreInfo restoreInfo = new RestoreInfo("remote_store", indicesToBeRestored, totalShards, totalShards);
+
+        RoutingTable rt = rtBuilder.build();
+        ClusterState updatedState = builder.metadata(mdBuilder).blocks(blocks).routingTable(rt).build();
+        return RemoteRestoreResult.build(restoreUUID, restoreInfo, allocationService.reroute(updatedState, "restored from remote store"));
+    }
+
+    /**
+     * Performs various validations needed before executing restore
+     * @param currentState current cluster state
+     * @param indexMetadataMap map of index metadata to restore
+     * @param restoreClusterUUID cluster UUID used to restore IndexMetadata
+     * @param restoreAllShards indicates if all shards of the index needs to be restored. This flat is ignored if remoteClusterUUID is provided
+     */
+    private void validate(
+        ClusterState currentState,
+        Map<String, Tuple<Boolean, IndexMetadata>> indexMetadataMap,
+        @Nullable String restoreClusterUUID,
+        boolean restoreAllShards
+    ) throws IllegalStateException, IllegalArgumentException {
+        String errorMsg = "cannot restore index [%s] because an open index with same name/uuid already exists in the cluster.";
+
+        // Restore with current cluster UUID will fail as same indices would be present in the cluster which we are trying to
+        // restore
+        if (currentState.metadata().clusterUUID().equals(restoreClusterUUID)) {
+            throw new IllegalArgumentException("clusterUUID to restore from should be different from current cluster UUID");
+        }
+        for (Map.Entry<String, Tuple<Boolean, IndexMetadata>> indexMetadataEntry : indexMetadataMap.entrySet()) {
+            String indexName = indexMetadataEntry.getKey();
+            IndexMetadata indexMetadata = indexMetadataEntry.getValue().v2();
+            String indexUUID = indexMetadata.getIndexUUID();
+            boolean metadataFromRemoteStore = indexMetadataEntry.getValue().v1();
+            if (indexMetadata.getSettings().getAsBoolean(SETTING_REMOTE_STORE_ENABLED, false)) {
+                if (metadataFromRemoteStore) {
+                    Set<String> graveyardIndexNames = new HashSet<>();
+                    Set<String> graveyardIndexUUID = new HashSet<>();
+                    Set<String> liveClusterIndexUUIDs = currentState.metadata()
+                        .indices()
+                        .values()
+                        .stream()
+                        .map(IndexMetadata::getIndexUUID)
+                        .collect(Collectors.toSet());
+
+                    currentState.metadata().indexGraveyard().getTombstones().forEach(tombstone -> {
+                        graveyardIndexNames.add(tombstone.getIndex().getName());
+                        graveyardIndexUUID.add(tombstone.getIndex().getUUID());
+                    });
+
+                    // Since updates to graveyard are synced to remote we should neven land in a situation where remote contain index
+                    // metadata for graveyard index.
+                    assert graveyardIndexNames.contains(indexName) == false : String.format(
+                        Locale.ROOT,
+                        "Index name [%s] exists in graveyard!",
+                        indexName
+                    );
+                    assert graveyardIndexUUID.contains(indexUUID) == false : String.format(
+                        Locale.ROOT,
+                        "Index UUID [%s] exists in graveyard!",
+                        indexUUID
+                    );
+
+                    // Any indices being restored from remote cluster state should not already be part of the cluster as this causes
+                    // conflict
+                    boolean sameNameIndexExists = currentState.metadata().hasIndex(indexName);
+                    boolean sameUUIDIndexExists = liveClusterIndexUUIDs.contains(indexUUID);
+                    if (sameNameIndexExists || sameUUIDIndexExists) {
+                        String finalErrorMsg = String.format(Locale.ROOT, errorMsg, indexName);
+                        logger.info(finalErrorMsg);
+                        throw new IllegalStateException(finalErrorMsg);
+                    }
+
+                    Version minIndexCompatibilityVersion = currentState.getNodes().getMaxNodeVersion().minimumIndexCompatibilityVersion();
+                    metadataIndexUpgradeService.upgradeIndexMetadata(indexMetadata, minIndexCompatibilityVersion);
+                    boolean isHidden = IndexMetadata.INDEX_HIDDEN_SETTING.get(indexMetadata.getSettings());
+                    createIndexService.validateIndexName(indexName, currentState);
+                    createIndexService.validateDotIndex(indexName, isHidden);
+                    shardLimitValidator.validateShardLimit(indexName, indexMetadata.getSettings(), currentState);
+                } else if (restoreAllShards && IndexMetadata.State.CLOSE.equals(indexMetadata.getState()) == false) {
+                    throw new IllegalStateException(String.format(Locale.ROOT, errorMsg, indexName) + " Close the existing index.");
+                }
+            } else {
+                logger.warn("Remote store is not enabled for index: {}", indexName);
+            }
+        }
+    }
+
+    /**
+     * Result of a remote restore operation.
+     */
+    public static class RemoteRestoreResult {
+        private final ClusterState clusterState;
+        private final RestoreInfo restoreInfo;
+        private final String restoreUUID;
+
+        private RemoteRestoreResult(String restoreUUID, RestoreInfo restoreInfo, ClusterState clusterState) {
+            this.clusterState = clusterState;
+            this.restoreInfo = restoreInfo;
+            this.restoreUUID = restoreUUID;
+        }
+
+        public static RemoteRestoreResult build(String restoreUUID, RestoreInfo restoreInfo, ClusterState clusterState) {
+            return new RemoteRestoreResult(restoreUUID, restoreInfo, clusterState);
+        }
+
+        public ClusterState getClusterState() {
+            return clusterState;
+        }
+
+        public RestoreInfo getRestoreInfo() {
+            return restoreInfo;
+        }
+
+        public String getRestoreUUID() {
+            return restoreUUID;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/recovery/package-info.java b/server/src/main/java/org/opensearch/index/recovery/package-info.java
new file mode 100644
index 0000000000000..44f4291157718
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/recovery/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Recovery stats implementation */
+package org.opensearch.index.recovery;
diff --git a/server/src/main/java/org/opensearch/index/refresh/RefreshStats.java b/server/src/main/java/org/opensearch/index/refresh/RefreshStats.java
index f673ab8ae03d4..86e500b0576b9 100644
--- a/server/src/main/java/org/opensearch/index/refresh/RefreshStats.java
+++ b/server/src/main/java/org/opensearch/index/refresh/RefreshStats.java
@@ -33,16 +33,21 @@
 package org.opensearch.index.refresh;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Encapsulates stats for index refresh
+ *
+ * @opensearch.internal
+ */
 public class RefreshStats implements Writeable, ToXContentFragment {
 
     private long total;
diff --git a/server/src/main/java/org/opensearch/index/refresh/package-info.java b/server/src/main/java/org/opensearch/index/refresh/package-info.java
new file mode 100644
index 0000000000000..fdd0f5658504f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/refresh/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Refresh stats implementation */
+package org.opensearch.index.refresh;
diff --git a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequest.java b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequest.java
index 0de9a50dd1e8d..4dea9ddc71f71 100644
--- a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequest.java
+++ b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequest.java
@@ -37,13 +37,13 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.replication.ReplicationRequest;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -53,6 +53,11 @@
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.common.unit.TimeValue.timeValueMinutes;
 
+/**
+ * Base class for requesting bulk by scrolls
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractBulkByScrollRequest<Self extends AbstractBulkByScrollRequest<Self>> extends ActionRequest {
 
     public static final int MAX_DOCS_ALL_MATCHES = -1;
diff --git a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestBuilder.java b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestBuilder.java
index bb729a4e8e2cb..ccba2d6f435f1 100644
--- a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestBuilder.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequestBuilder;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.replication.ReplicationRequest;
@@ -41,6 +41,11 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.index.query.QueryBuilder;
 
+/**
+ * Base builder for bulk by scroll requests
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractBulkByScrollRequestBuilder<
     Request extends AbstractBulkByScrollRequest<Request>,
     Self extends AbstractBulkByScrollRequestBuilder<Request, Self>> extends ActionRequestBuilder<Request, BulkByScrollResponse> {
diff --git a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequest.java b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequest.java
index 27c655ee11087..9d63658f4a67c 100644
--- a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequest.java
+++ b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequest.java
@@ -34,13 +34,18 @@
 
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.script.Script;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 
+/**
+ * Base request class for bulk indexing by scroll
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractBulkIndexByScrollRequest<Self extends AbstractBulkIndexByScrollRequest<Self>> extends
     AbstractBulkByScrollRequest<Self> {
     /**
diff --git a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequestBuilder.java b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequestBuilder.java
index f26d54d3e2265..2dda25b52f6be 100644
--- a/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/AbstractBulkIndexByScrollRequestBuilder.java
@@ -37,6 +37,11 @@
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.script.Script;
 
+/**
+ * Base builder class for bulk index by scrolls
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractBulkIndexByScrollRequestBuilder<
     Request extends AbstractBulkIndexByScrollRequest<Request>,
     Self extends AbstractBulkIndexByScrollRequestBuilder<Request, Self>> extends AbstractBulkByScrollRequestBuilder<Request, Self> {
diff --git a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponse.java b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponse.java
index 6a4b55f5877e7..0f3714fb16754 100644
--- a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponse.java
+++ b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponse.java
@@ -34,21 +34,21 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.bulk.BulkItemResponse.Failure;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.index.reindex.BulkByScrollTask.Status;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
+import org.opensearch.index.reindex.BulkByScrollTask.Status;
 import org.opensearch.index.reindex.ScrollableHitSource.SearchFailure;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -58,10 +58,12 @@
 import static java.lang.Math.min;
 import static java.util.Objects.requireNonNull;
 import static org.opensearch.common.unit.TimeValue.timeValueNanos;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Response used for actions that index many documents using a scroll request.
+ *
+ * @opensearch.internal
  */
 public class BulkByScrollResponse extends ActionResponse implements ToXContentFragment {
     private TimeValue took;
diff --git a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponseBuilder.java b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponseBuilder.java
index db8d85ac5c8d9..f1a9d1322412c 100644
--- a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponseBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollResponseBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.common.unit.TimeValue;
 import org.opensearch.action.bulk.BulkItemResponse.Failure;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.index.reindex.ScrollableHitSource.SearchFailure;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.xcontent.ObjectParser;
 import org.opensearch.index.reindex.BulkByScrollTask.StatusBuilder;
+import org.opensearch.index.reindex.ScrollableHitSource.SearchFailure;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -44,6 +44,8 @@
 
 /**
  * Helps build a {@link BulkByScrollResponse}. Used by an instance of {@link ObjectParser} when parsing from XContent.
+ *
+ * @opensearch.internal
  */
 class BulkByScrollResponseBuilder extends StatusBuilder {
     private TimeValue took;
diff --git a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollTask.java b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollTask.java
index e792adb9a32f9..f33800659245f 100644
--- a/server/src/main/java/org/opensearch/index/reindex/BulkByScrollTask.java
+++ b/server/src/main/java/org/opensearch/index/reindex/BulkByScrollTask.java
@@ -34,23 +34,24 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 
 import java.io.IOException;
@@ -67,8 +68,8 @@
 import static java.lang.Math.min;
 import static java.util.Collections.emptyList;
 import static org.opensearch.common.unit.TimeValue.timeValueNanos;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Task storing information about a currently running BulkByScroll request.
@@ -82,6 +83,8 @@
  * We don't always know if this task will be a leader or worker task when it's created, because if slices is set to "auto" it may
  * be either depending on the number of shards in the source indices. We figure that out when the request is handled and set it on this
  * class with {@link #setWorkerCount(int)} or {@link #setWorker(float, Integer)}.
+ *
+ * @opensearch.internal
  */
 public class BulkByScrollTask extends CancellableTask {
 
@@ -220,6 +223,8 @@ public boolean shouldCancelChildrenOnCancellation() {
      * This class acts as a builder for {@link Status}. Once the {@link Status} object is built by calling
      * {@link #buildStatus()} it is immutable. Used by an instance of {@link ObjectParser} when parsing from
      * XContent.
+     *
+     * @opensearch.internal
      */
     public static class StatusBuilder {
         private Integer sliceId = null;
@@ -353,6 +358,8 @@ public Status buildStatus() {
      * implementations, this one has become defacto standardized because Kibana
      * parses it. As such, we should be very careful about removing things from
      * this.
+     *
+     * @opensearch.internal
      */
     public static class Status implements Task.Status, SuccessfullyProcessed {
         public static final String NAME = "bulk-by-scroll";
@@ -925,6 +932,8 @@ private long checkPositive(long value, String name) {
     /**
      * The status of a slice of the request. Successful requests store the {@link StatusOrException#status} while failing requests store a
      * {@link StatusOrException#exception}.
+     *
+     * @opensearch.internal
      */
     public static class StatusOrException implements Writeable, ToXContentObject {
         private final Status status;
@@ -1039,9 +1048,9 @@ public static StatusOrException fromXContent(XContentParser parser) throws IOExc
         @Override
         public String toString() {
             if (exception != null) {
-                return "BulkByScrollTask{error=" + Strings.toString(this) + "}";
+                return "BulkByScrollTask{error=" + Strings.toString(MediaTypeRegistry.JSON, this) + "}";
             } else {
-                return "BulkByScrollTask{status=" + Strings.toString(this) + "}";
+                return "BulkByScrollTask{status=" + Strings.toString(MediaTypeRegistry.JSON, this) + "}";
             }
         }
 
diff --git a/server/src/main/java/org/opensearch/index/reindex/ClientScrollableHitSource.java b/server/src/main/java/org/opensearch/index/reindex/ClientScrollableHitSource.java
index 6a78d16d3b385..55d018af46970 100644
--- a/server/src/main/java/org/opensearch/index/reindex/ClientScrollableHitSource.java
+++ b/server/src/main/java/org/opensearch/index/reindex/ClientScrollableHitSource.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollResponse;
@@ -45,12 +44,13 @@
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.client.Client;
 import org.opensearch.client.ParentTaskAssigningClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.RoutingFieldMapper;
 import org.opensearch.search.SearchHit;
 import org.opensearch.threadpool.ThreadPool;
@@ -62,10 +62,12 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.common.unit.TimeValue.timeValueNanos;
-import static org.opensearch.common.util.CollectionUtils.isEmpty;
+import static org.opensearch.core.common.util.CollectionUtils.isEmpty;
 
 /**
  * A scrollable source of hits from a {@linkplain Client} instance.
+ *
+ * @opensearch.internal
  */
 public class ClientScrollableHitSource extends ScrollableHitSource {
     private final ParentTaskAssigningClient client;
@@ -177,6 +179,11 @@ private Response wrapSearchResponse(SearchResponse response) {
         return new Response(response.isTimedOut(), failures, total, hits, response.getScrollId());
     }
 
+    /**
+     * A Client hit
+     *
+     * @opensearch.internal
+     */
     private static class ClientHit implements Hit {
         private final SearchHit delegate;
         private final BytesReference source;
@@ -202,8 +209,8 @@ public BytesReference getSource() {
         }
 
         @Override
-        public XContentType getXContentType() {
-            return XContentHelper.xContentType(source);
+        public MediaType getMediaType() {
+            return MediaTypeRegistry.xContentType(source);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryAction.java b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryAction.java
index eda40576b7190..5292c793e9c3c 100644
--- a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryAction.java
+++ b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action type for delete by query
+ *
+ * @opensearch.internal
+ */
 public class DeleteByQueryAction extends ActionType<BulkByScrollResponse> {
 
     public static final DeleteByQueryAction INSTANCE = new DeleteByQueryAction();
diff --git a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequest.java b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequest.java
index 4f297b89c0651..aff9ec1f20e46 100644
--- a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequest.java
+++ b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequest.java
@@ -36,11 +36,11 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 
@@ -62,6 +62,8 @@
  *     stored in the transaction logs that might not be supported in the future.</li>
  *     <li>it's results won't be visible until the index is refreshed.</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public class DeleteByQueryRequest extends AbstractBulkByScrollRequest<DeleteByQueryRequest>
     implements
diff --git a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequestBuilder.java b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequestBuilder.java
index a508536245e9b..bfc0a1b77c580 100644
--- a/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/DeleteByQueryRequestBuilder.java
@@ -37,6 +37,11 @@
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Builder for delete by query
+ *
+ * @opensearch.internal
+ */
 public class DeleteByQueryRequestBuilder extends AbstractBulkByScrollRequestBuilder<DeleteByQueryRequest, DeleteByQueryRequestBuilder> {
 
     public DeleteByQueryRequestBuilder(OpenSearchClient client, ActionType<BulkByScrollResponse> action) {
diff --git a/server/src/main/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskState.java b/server/src/main/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskState.java
index 1edc48c3b0d90..39ff9478cb13e 100644
--- a/server/src/main/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskState.java
+++ b/server/src/main/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskState.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -44,6 +44,8 @@
 
 /**
  * Tracks the state of sliced subtasks and provides unified status information for a sliced BulkByScrollRequest.
+ *
+ * @opensearch.internal
  */
 public class LeaderBulkByScrollTaskState {
 
@@ -154,6 +156,11 @@ private void recordSliceCompletionAndRespondIfAllDone(ActionListener<BulkByScrol
         }
     }
 
+    /**
+     * Result
+     *
+     * @opensearch.internal
+     */
     private static final class Result {
         final BulkByScrollResponse response;
         final int sliceId;
diff --git a/server/src/main/java/org/opensearch/index/reindex/ReindexAction.java b/server/src/main/java/org/opensearch/index/reindex/ReindexAction.java
index 6888cd1262579..e4695b34af497 100644
--- a/server/src/main/java/org/opensearch/index/reindex/ReindexAction.java
+++ b/server/src/main/java/org/opensearch/index/reindex/ReindexAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action type for reindex requests
+ *
+ * @opensearch.internal
+ */
 public class ReindexAction extends ActionType<BulkByScrollResponse> {
     public static final ReindexAction INSTANCE = new ReindexAction();
     public static final String NAME = "indices:data/write/reindex";
diff --git a/server/src/main/java/org/opensearch/index/reindex/ReindexRequest.java b/server/src/main/java/org/opensearch/index/reindex/ReindexRequest.java
index 5858b4b8108d2..03608c1b1e9af 100644
--- a/server/src/main/java/org/opensearch/index/reindex/ReindexRequest.java
+++ b/server/src/main/java/org/opensearch/index/reindex/ReindexRequest.java
@@ -36,24 +36,24 @@
 import org.opensearch.action.CompositeIndicesRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.script.Script;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -73,6 +73,8 @@
  * returning all the subrequests that it will make it tries to return a representative set of subrequests. This is best-effort for a bunch
  * of reasons, not least of which that scripts are allowed to change the destination request in drastic ways, including changing the index
  * to which documents are written.
+ *
+ * @opensearch.internal
  */
 public class ReindexRequest extends AbstractBulkIndexByScrollRequest<ReindexRequest> implements CompositeIndicesRequest, ToXContentObject {
     /**
@@ -305,7 +307,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.startObject("source");
             if (remoteInfo != null) {
                 builder.field("remote", remoteInfo);
-                builder.rawField("query", remoteInfo.getQuery().streamInput(), RemoteInfo.QUERY_CONTENT_TYPE.type());
+                builder.rawField("query", remoteInfo.getQuery().streamInput(), RemoteInfo.QUERY_CONTENT_TYPE.mediaType());
             }
             builder.array("index", getSearchRequest().indices());
             getSearchRequest().source().innerToXContent(builder, params);
@@ -354,7 +356,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                 request.getSearchRequest().indices(indices);
             }
             request.setRemoteInfo(buildRemoteInfo(source));
-            XContentBuilder builder = XContentFactory.contentBuilder(parser.contentType());
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(parser.contentType());
             builder.map(source);
             try (
                 InputStream stream = BytesReference.bytes(builder).streamInput();
diff --git a/server/src/main/java/org/opensearch/index/reindex/ReindexRequestBuilder.java b/server/src/main/java/org/opensearch/index/reindex/ReindexRequestBuilder.java
index 291acd1e8ad8d..c59b5885c25be 100644
--- a/server/src/main/java/org/opensearch/index/reindex/ReindexRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/ReindexRequestBuilder.java
@@ -39,6 +39,11 @@
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Builder for reindex requests
+ *
+ * @opensearch.internal
+ */
 public class ReindexRequestBuilder extends AbstractBulkIndexByScrollRequestBuilder<ReindexRequest, ReindexRequestBuilder> {
     private final IndexRequestBuilder destination;
 
diff --git a/server/src/main/java/org/opensearch/index/reindex/RejectAwareActionListener.java b/server/src/main/java/org/opensearch/index/reindex/RejectAwareActionListener.java
index 1e5f10ce30915..04e3d2a6c6c83 100644
--- a/server/src/main/java/org/opensearch/index/reindex/RejectAwareActionListener.java
+++ b/server/src/main/java/org/opensearch/index/reindex/RejectAwareActionListener.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.CheckedConsumer;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.function.Consumer;
 
+/**
+ * Action listener for rejections
+ *
+ * @opensearch.internal
+ */
 // public for testing
 public interface RejectAwareActionListener<T> extends ActionListener<T> {
     void onRejection(Exception e);
diff --git a/server/src/main/java/org/opensearch/index/reindex/RemoteInfo.java b/server/src/main/java/org/opensearch/index/reindex/RemoteInfo.java
index 03d0ab072a5a1..37df0a6aef85d 100644
--- a/server/src/main/java/org/opensearch/index/reindex/RemoteInfo.java
+++ b/server/src/main/java/org/opensearch/index/reindex/RemoteInfo.java
@@ -33,19 +33,19 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -57,6 +57,11 @@
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 
+/**
+ * Encapsulates informatoin for remote resources
+ *
+ * @opensearch.internal
+ */
 public class RemoteInfo implements Writeable, ToXContentObject {
     /**
      * Default {@link #socketTimeout} for requests that don't have one set.
diff --git a/server/src/main/java/org/opensearch/index/reindex/RetryListener.java b/server/src/main/java/org/opensearch/index/reindex/RetryListener.java
index a3d469ba66ebc..2b092539555e6 100644
--- a/server/src/main/java/org/opensearch/index/reindex/RetryListener.java
+++ b/server/src/main/java/org/opensearch/index/reindex/RetryListener.java
@@ -34,14 +34,19 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.Iterator;
 import java.util.function.Consumer;
 
+/**
+ * Base listener for retries
+ *
+ * @opensearch.internal
+ */
 class RetryListener implements RejectAwareActionListener<ScrollableHitSource.Response> {
     private final Logger logger;
     private final Iterator<TimeValue> retries;
diff --git a/server/src/main/java/org/opensearch/index/reindex/ScrollableHitSource.java b/server/src/main/java/org/opensearch/index/reindex/ScrollableHitSource.java
index f0c720e21a73e..8b18a2c6b086e 100644
--- a/server/src/main/java/org/opensearch/index/reindex/ScrollableHitSource.java
+++ b/server/src/main/java/org/opensearch/index/reindex/ScrollableHitSource.java
@@ -33,24 +33,25 @@
 package org.opensearch.index.reindex;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.bulk.BackoffPolicy;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchHit;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -66,6 +67,8 @@
  * A scrollable source of results. Pumps data out into the passed onResponse consumer. Same data may come out several times in case
  * of failures during searching (though not yet). Once the onResponse consumer is done, it should call AsyncResponse.isDone(time) to receive
  * more data (only receives one response at a time).
+ *
+ * @opensearch.internal
  */
 public abstract class ScrollableHitSource {
     private final AtomicReference<String> scrollId = new AtomicReference<>();
@@ -176,6 +179,11 @@ public final void setScroll(String scrollId) {
         this.scrollId.set(scrollId);
     }
 
+    /**
+     * Asynchronous response
+     *
+     * @opensearch.internal
+     */
     public interface AsyncResponse {
         /**
          * The response data made available.
@@ -191,6 +199,8 @@ public interface AsyncResponse {
 
     /**
      * Response from each scroll batch.
+     *
+     * @opensearch.internal
      */
     public static class Response {
         private final boolean timedOut;
@@ -246,6 +256,8 @@ public String getScrollId() {
     /**
      * A document returned as part of the response. Think of it like {@link SearchHit} but with all the things reindex needs in convenient
      * methods.
+     *
+     * @opensearch.internal
      */
     public interface Hit {
         /**
@@ -285,7 +297,7 @@ public interface Hit {
          * The content type of the hit source. Returns null if the source didn't come back from the search.
          */
         @Nullable
-        XContentType getXContentType();
+        MediaType getMediaType();
 
         /**
          * The routing on the hit if there is any or null if there isn't.
@@ -296,6 +308,8 @@ public interface Hit {
 
     /**
      * An implementation of {@linkplain Hit} that uses getters and setters.
+     *
+     * @opensearch.internal
      */
     public static class BasicHit implements Hit {
         private final String index;
@@ -303,7 +317,7 @@ public static class BasicHit implements Hit {
         private final long version;
 
         private BytesReference source;
-        private XContentType xContentType;
+        private MediaType mediaType;
         private String routing;
         private long seqNo;
         private long primaryTerm;
@@ -345,13 +359,13 @@ public BytesReference getSource() {
         }
 
         @Override
-        public XContentType getXContentType() {
-            return xContentType;
+        public MediaType getMediaType() {
+            return mediaType;
         }
 
-        public BasicHit setSource(BytesReference source, XContentType xContentType) {
+        public BasicHit setSource(BytesReference source, MediaType mediaType) {
             this.source = source;
-            this.xContentType = xContentType;
+            this.mediaType = mediaType;
             return this;
         }
 
@@ -376,6 +390,8 @@ public void setPrimaryTerm(long primaryTerm) {
 
     /**
      * A failure during search. Like {@link ShardSearchFailure} but useful for reindex from remote as well.
+     *
+     * @opensearch.internal
      */
     public static class SearchFailure implements Writeable, ToXContentObject {
         private final Throwable reason;
@@ -483,7 +499,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/reindex/SuccessfullyProcessed.java b/server/src/main/java/org/opensearch/index/reindex/SuccessfullyProcessed.java
index 94aa5b77f541a..343f5e2a1c52b 100644
--- a/server/src/main/java/org/opensearch/index/reindex/SuccessfullyProcessed.java
+++ b/server/src/main/java/org/opensearch/index/reindex/SuccessfullyProcessed.java
@@ -35,6 +35,8 @@
 /**
  * Implemented by {@link WorkerBulkByScrollTaskState} and {@link BulkByScrollTask.Status} to consistently implement
  * {@link #getSuccessfullyProcessed()}.
+ *
+ * @opensearch.internal
  */
 public interface SuccessfullyProcessed {
     /**
diff --git a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryAction.java b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryAction.java
index 8facce990be6f..322a552b310fb 100644
--- a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryAction.java
+++ b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryAction.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.action.ActionType;
 
+/**
+ * Action type for updating by query
+ *
+ * @opensearch.internal
+ */
 public class UpdateByQueryAction extends ActionType<BulkByScrollResponse> {
     public static final UpdateByQueryAction INSTANCE = new UpdateByQueryAction();
     public static final String NAME = "indices:data/write/update/byquery";
diff --git a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequest.java b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequest.java
index 92bcef8455e63..d47ed239c22f2 100644
--- a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequest.java
+++ b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequest.java
@@ -35,12 +35,12 @@
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 
@@ -49,6 +49,8 @@
  * CompositeIndicesRequest but in a misleading way. Rather than returning all the subrequests that it will make it tries to return a
  * representative set of subrequests. This is best-effort but better than {@linkplain ReindexRequest} because scripts can't change the
  * destination index and things.
+ *
+ * @opensearch.internal
  */
 public class UpdateByQueryRequest extends AbstractBulkIndexByScrollRequest<UpdateByQueryRequest>
     implements
diff --git a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequestBuilder.java b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequestBuilder.java
index f2184167a1eb7..1e4847157b0bb 100644
--- a/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequestBuilder.java
+++ b/server/src/main/java/org/opensearch/index/reindex/UpdateByQueryRequestBuilder.java
@@ -37,6 +37,11 @@
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.client.OpenSearchClient;
 
+/**
+ * Request builder for updating a document by query
+ *
+ * @opensearch.internal
+ */
 public class UpdateByQueryRequestBuilder extends AbstractBulkIndexByScrollRequestBuilder<
     UpdateByQueryRequest,
     UpdateByQueryRequestBuilder> {
diff --git a/server/src/main/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskState.java b/server/src/main/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskState.java
index 2846298e005e7..c9661c6e00c64 100644
--- a/server/src/main/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskState.java
+++ b/server/src/main/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskState.java
@@ -36,8 +36,8 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.RunOnce;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -53,6 +53,8 @@
 
 /**
  * Task behavior for {@link BulkByScrollTask} that does the actual work of querying and indexing
+ *
+ * @opensearch.internal
  */
 public class WorkerBulkByScrollTaskState implements SuccessfullyProcessed {
 
diff --git a/server/src/main/java/org/opensearch/index/reindex/package-info.java b/server/src/main/java/org/opensearch/index/reindex/package-info.java
new file mode 100644
index 0000000000000..b3374e4b1853d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/reindex/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Reindex implementation */
+package org.opensearch.index.reindex;
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteSegmentStats.java b/server/src/main/java/org/opensearch/index/remote/RemoteSegmentStats.java
new file mode 100644
index 0000000000000..c7863536adf20
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteSegmentStats.java
@@ -0,0 +1,340 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStats;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.shard.IndexShard;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Tracks remote store segment download and upload stats
+ * Used for displaying remote store stats in IndicesStats/NodeStats API
+ *
+ * @opensearch.internal
+ */
+public class RemoteSegmentStats implements Writeable, ToXContentFragment {
+    /**
+     * Cumulative bytes attempted to be uploaded to remote store
+     */
+    private long uploadBytesStarted;
+    /**
+     * Cumulative bytes failed to be uploaded to the remote store
+     */
+    private long uploadBytesFailed;
+    /**
+     * Cumulative bytes successfully uploaded to the remote store
+     */
+    private long uploadBytesSucceeded;
+    /**
+     * Cumulative bytes attempted to be downloaded from the remote store
+     */
+    private long downloadBytesStarted;
+    /**
+     * Cumulative bytes failed to be downloaded from the remote store
+     */
+    private long downloadBytesFailed;
+    /**
+     * Cumulative bytes successfully downloaded from the remote store
+     */
+    private long downloadBytesSucceeded;
+    /**
+     * Maximum refresh lag (in milliseconds) between local and the remote store
+     * Used to check for data freshness in the remote store
+     */
+    private long maxRefreshTimeLag;
+    /**
+     * Maximum refresh lag (in bytes) between local and the remote store
+     * Used to check for data freshness in the remote store
+     */
+    private long maxRefreshBytesLag;
+    /**
+     * Total refresh lag (in bytes) between local and the remote store
+     * Used to check for data freshness in the remote store
+     */
+    private long totalRefreshBytesLag;
+    /**
+     * Total time spent in uploading segments to remote store
+     */
+    private long totalUploadTime;
+    /**
+     * Total time spent in downloading segments from remote store
+     */
+    private long totalDownloadTime;
+
+    public RemoteSegmentStats() {}
+
+    public RemoteSegmentStats(StreamInput in) throws IOException {
+        uploadBytesStarted = in.readLong();
+        uploadBytesFailed = in.readLong();
+        uploadBytesSucceeded = in.readLong();
+        downloadBytesStarted = in.readLong();
+        downloadBytesFailed = in.readLong();
+        downloadBytesSucceeded = in.readLong();
+        maxRefreshTimeLag = in.readLong();
+        maxRefreshBytesLag = in.readLong();
+        totalRefreshBytesLag = in.readLong();
+        totalUploadTime = in.readLong();
+        totalDownloadTime = in.readLong();
+    }
+
+    /**
+     * Constructor to retrieve metrics from {@link RemoteSegmentTransferTracker.Stats} which is used in {@link RemoteStoreStats} and
+     * provides verbose index level stats of segments transferred to the remote store.
+     * <p>
+     * This method is used in {@link IndexShard} to port over a subset of metrics to be displayed in IndexStats and subsequently rolled up to NodesStats
+     *
+     * @param trackerStats: Source {@link RemoteSegmentTransferTracker.Stats} object from which metrics would be retrieved
+     */
+    public RemoteSegmentStats(RemoteSegmentTransferTracker.Stats trackerStats) {
+        this.uploadBytesStarted = trackerStats.uploadBytesStarted;
+        this.uploadBytesFailed = trackerStats.uploadBytesFailed;
+        this.uploadBytesSucceeded = trackerStats.uploadBytesSucceeded;
+        this.downloadBytesSucceeded = trackerStats.directoryFileTransferTrackerStats.transferredBytesSucceeded;
+        this.downloadBytesStarted = trackerStats.directoryFileTransferTrackerStats.transferredBytesStarted;
+        this.downloadBytesFailed = trackerStats.directoryFileTransferTrackerStats.transferredBytesFailed;
+        this.maxRefreshTimeLag = trackerStats.refreshTimeLagMs;
+        // Initializing both total and max bytes lag to the same `bytesLag`
+        // value from the tracker object
+        // Aggregations would be performed on the add method
+        this.maxRefreshBytesLag = trackerStats.bytesLag;
+        this.totalRefreshBytesLag = trackerStats.bytesLag;
+        this.totalUploadTime = trackerStats.totalUploadTimeInMs;
+        this.totalDownloadTime = trackerStats.directoryFileTransferTrackerStats.totalTransferTimeInMs;
+    }
+
+    // Getter and setters. All are visible for testing
+    // Setters are only used for testing
+    public long getUploadBytesStarted() {
+        return uploadBytesStarted;
+    }
+
+    public void addUploadBytesStarted(long uploadsStarted) {
+        this.uploadBytesStarted += uploadsStarted;
+    }
+
+    public long getUploadBytesFailed() {
+        return uploadBytesFailed;
+    }
+
+    public void addUploadBytesFailed(long uploadsFailed) {
+        this.uploadBytesFailed += uploadsFailed;
+    }
+
+    public long getUploadBytesSucceeded() {
+        return uploadBytesSucceeded;
+    }
+
+    public void addUploadBytesSucceeded(long uploadsSucceeded) {
+        this.uploadBytesSucceeded += uploadsSucceeded;
+    }
+
+    public long getDownloadBytesStarted() {
+        return downloadBytesStarted;
+    }
+
+    public void addDownloadBytesStarted(long downloadsStarted) {
+        this.downloadBytesStarted += downloadsStarted;
+    }
+
+    public long getDownloadBytesFailed() {
+        return downloadBytesFailed;
+    }
+
+    public void addDownloadBytesFailed(long downloadsFailed) {
+        this.downloadBytesFailed += downloadsFailed;
+    }
+
+    public long getDownloadBytesSucceeded() {
+        return downloadBytesSucceeded;
+    }
+
+    public void addDownloadBytesSucceeded(long downloadsSucceeded) {
+        this.downloadBytesSucceeded += downloadsSucceeded;
+    }
+
+    public long getMaxRefreshTimeLag() {
+        return maxRefreshTimeLag;
+    }
+
+    public void setMaxRefreshTimeLag(long maxRefreshTimeLag) {
+        this.maxRefreshTimeLag = Math.max(this.maxRefreshTimeLag, maxRefreshTimeLag);
+    }
+
+    public long getMaxRefreshBytesLag() {
+        return maxRefreshBytesLag;
+    }
+
+    public void addMaxRefreshBytesLag(long maxRefreshBytesLag) {
+        this.maxRefreshBytesLag = Math.max(this.maxRefreshBytesLag, maxRefreshBytesLag);
+    }
+
+    public long getTotalRefreshBytesLag() {
+        return totalRefreshBytesLag;
+    }
+
+    public void addTotalRefreshBytesLag(long totalRefreshBytesLag) {
+        this.totalRefreshBytesLag += totalRefreshBytesLag;
+    }
+
+    public long getTotalUploadTime() {
+        return totalUploadTime;
+    }
+
+    public void addTotalUploadTime(long totalUploadTime) {
+        this.totalUploadTime += totalUploadTime;
+    }
+
+    public long getTotalDownloadTime() {
+        return totalDownloadTime;
+    }
+
+    public void addTotalDownloadTime(long totalDownloadTime) {
+        this.totalDownloadTime += totalDownloadTime;
+    }
+
+    /**
+     * Adds existing stats. Used for stats roll-ups at index or node level
+     *
+     * @param existingStats: Existing {@link RemoteSegmentStats} to add
+     */
+    public void add(RemoteSegmentStats existingStats) {
+        if (existingStats != null) {
+            this.uploadBytesStarted += existingStats.getUploadBytesStarted();
+            this.uploadBytesSucceeded += existingStats.getUploadBytesSucceeded();
+            this.uploadBytesFailed += existingStats.getUploadBytesFailed();
+            this.downloadBytesStarted += existingStats.getDownloadBytesStarted();
+            this.downloadBytesFailed += existingStats.getDownloadBytesFailed();
+            this.downloadBytesSucceeded += existingStats.getDownloadBytesSucceeded();
+            this.maxRefreshTimeLag = Math.max(this.maxRefreshTimeLag, existingStats.getMaxRefreshTimeLag());
+            this.maxRefreshBytesLag = Math.max(this.maxRefreshBytesLag, existingStats.getMaxRefreshBytesLag());
+            this.totalRefreshBytesLag += existingStats.getTotalRefreshBytesLag();
+            this.totalUploadTime += existingStats.getTotalUploadTime();
+            this.totalDownloadTime += existingStats.getTotalDownloadTime();
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeLong(uploadBytesStarted);
+        out.writeLong(uploadBytesFailed);
+        out.writeLong(uploadBytesSucceeded);
+        out.writeLong(downloadBytesStarted);
+        out.writeLong(downloadBytesFailed);
+        out.writeLong(downloadBytesSucceeded);
+        out.writeLong(maxRefreshTimeLag);
+        out.writeLong(maxRefreshBytesLag);
+        out.writeLong(totalRefreshBytesLag);
+        out.writeLong(totalUploadTime);
+        out.writeLong(totalDownloadTime);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(Fields.REMOTE_STORE);
+        builder.startObject(Fields.UPLOAD);
+        buildUploadStats(builder);
+        builder.endObject();
+        builder.startObject(Fields.DOWNLOAD);
+        buildDownloadStats(builder);
+        builder.endObject();
+        builder.endObject();
+        return builder;
+    }
+
+    private void buildUploadStats(XContentBuilder builder) throws IOException {
+        builder.startObject(Fields.TOTAL_UPLOAD_SIZE);
+        builder.humanReadableField(Fields.STARTED_BYTES, Fields.STARTED, new ByteSizeValue(uploadBytesStarted));
+        builder.humanReadableField(Fields.SUCCEEDED_BYTES, Fields.SUCCEEDED, new ByteSizeValue(uploadBytesSucceeded));
+        builder.humanReadableField(Fields.FAILED_BYTES, Fields.FAILED, new ByteSizeValue(uploadBytesFailed));
+        builder.endObject();
+        builder.startObject(Fields.REFRESH_SIZE_LAG);
+        builder.humanReadableField(Fields.TOTAL_BYTES, Fields.TOTAL, new ByteSizeValue(totalRefreshBytesLag));
+        builder.humanReadableField(Fields.MAX_BYTES, Fields.MAX, new ByteSizeValue(maxRefreshBytesLag));
+        builder.endObject();
+        builder.humanReadableField(Fields.MAX_REFRESH_TIME_LAG_IN_MILLIS, Fields.MAX_REFRESH_TIME_LAG, new TimeValue(maxRefreshTimeLag));
+        builder.humanReadableField(Fields.TOTAL_TIME_SPENT_IN_MILLIS, Fields.TOTAL_TIME_SPENT, new TimeValue(totalUploadTime));
+    }
+
+    private void buildDownloadStats(XContentBuilder builder) throws IOException {
+        builder.startObject(Fields.TOTAL_DOWNLOAD_SIZE);
+        builder.humanReadableField(Fields.STARTED_BYTES, Fields.STARTED, new ByteSizeValue(downloadBytesStarted));
+        builder.humanReadableField(Fields.SUCCEEDED_BYTES, Fields.SUCCEEDED, new ByteSizeValue(downloadBytesSucceeded));
+        builder.humanReadableField(Fields.FAILED_BYTES, Fields.FAILED, new ByteSizeValue(downloadBytesFailed));
+        builder.endObject();
+        builder.humanReadableField(Fields.TOTAL_TIME_SPENT_IN_MILLIS, Fields.TOTAL_TIME_SPENT, new TimeValue(totalDownloadTime));
+    }
+
+    static final class Fields {
+        static final String REMOTE_STORE = "remote_store";
+        static final String UPLOAD = "upload";
+        static final String DOWNLOAD = "download";
+        static final String TOTAL_UPLOAD_SIZE = "total_upload_size";
+        static final String TOTAL_DOWNLOAD_SIZE = "total_download_size";
+        static final String MAX_REFRESH_TIME_LAG = "max_refresh_time_lag";
+        static final String MAX_REFRESH_TIME_LAG_IN_MILLIS = "max_refresh_time_lag_in_millis";
+        static final String REFRESH_SIZE_LAG = "refresh_size_lag";
+        static final String STARTED = "started";
+        static final String STARTED_BYTES = "started_bytes";
+        static final String FAILED = "failed";
+        static final String FAILED_BYTES = "failed_bytes";
+        static final String SUCCEEDED = "succeeded";
+        static final String SUCCEEDED_BYTES = "succeeded_bytes";
+        static final String TOTAL = "total";
+        static final String TOTAL_BYTES = "total_bytes";
+        static final String MAX = "max";
+        static final String MAX_BYTES = "max_bytes";
+        static final String TOTAL_TIME_SPENT = "total_time_spent";
+        static final String TOTAL_TIME_SPENT_IN_MILLIS = "total_time_spent_in_millis";
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        RemoteSegmentStats that = (RemoteSegmentStats) o;
+        return uploadBytesStarted == that.uploadBytesStarted
+            && uploadBytesFailed == that.uploadBytesFailed
+            && uploadBytesSucceeded == that.uploadBytesSucceeded
+            && downloadBytesStarted == that.downloadBytesStarted
+            && downloadBytesFailed == that.downloadBytesFailed
+            && downloadBytesSucceeded == that.downloadBytesSucceeded
+            && maxRefreshTimeLag == that.maxRefreshTimeLag
+            && maxRefreshBytesLag == that.maxRefreshBytesLag
+            && totalRefreshBytesLag == that.totalRefreshBytesLag
+            && totalUploadTime == that.totalUploadTime
+            && totalDownloadTime == that.totalDownloadTime;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(
+            uploadBytesStarted,
+            uploadBytesFailed,
+            uploadBytesSucceeded,
+            downloadBytesStarted,
+            downloadBytesFailed,
+            downloadBytesSucceeded,
+            maxRefreshTimeLag,
+            maxRefreshBytesLag,
+            totalRefreshBytesLag,
+            totalUploadTime,
+            totalDownloadTime
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteSegmentTransferTracker.java b/server/src/main/java/org/opensearch/index/remote/RemoteSegmentTransferTracker.java
new file mode 100644
index 0000000000000..05081180bb179
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteSegmentTransferTracker.java
@@ -0,0 +1,561 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.util.Streak;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.DirectoryFileTransferTracker;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.shard.RemoteStoreRefreshListener.EXCLUDE_FILES;
+
+/**
+ * Keeps track of remote refresh which happens in {@link org.opensearch.index.shard.RemoteStoreRefreshListener}. This consist of multiple critical metrics.
+ *
+ * @opensearch.internal
+ */
+public class RemoteSegmentTransferTracker extends RemoteTransferTracker {
+
+    private final Logger logger;
+
+    /**
+     * Every refresh is assigned a sequence number. This is the sequence number of the most recent refresh.
+     */
+    private volatile long localRefreshSeqNo;
+
+    /**
+     * The refresh time of the most recent refresh.
+     */
+    private volatile long localRefreshTimeMs;
+
+    /**
+     * The refresh time(clock) of the most recent refresh.
+     */
+    private volatile long localRefreshClockTimeMs;
+
+    /**
+     * Sequence number of the most recent remote refresh.
+     */
+    private volatile long remoteRefreshSeqNo;
+
+    /**
+     * The refresh time of most recent remote refresh.
+     */
+    private volatile long remoteRefreshTimeMs;
+
+    /**
+     * The refresh time(clock) of most recent remote refresh.
+     */
+    private volatile long remoteRefreshClockTimeMs;
+
+    /**
+     * Keeps the seq no lag computed so that we do not compute it for every request.
+     */
+    private volatile long refreshSeqNoLag;
+
+    /**
+     * Keeps the time (ms) lag computed so that we do not compute it for every request.
+     */
+    private volatile long timeMsLag;
+
+    /**
+     * Keeps track of the total bytes of segment files which were uploaded to remote store during last successful remote refresh
+     */
+    private volatile long lastSuccessfulRemoteRefreshBytes;
+
+    /**
+     * Cumulative sum of rejection counts for this shard.
+     */
+    private final AtomicLong rejectionCount = new AtomicLong();
+
+    /**
+     * Keeps track of rejection count with each rejection reason.
+     */
+    private final Map<String, AtomicLong> rejectionCountMap = ConcurrentCollections.newConcurrentMap();
+
+    /**
+     * Keeps track of segment files and their size in bytes which are part of the most recent refresh.
+     */
+    private final Map<String, Long> latestLocalFileNameLengthMap = ConcurrentCollections.newConcurrentMap();
+
+    /**
+     * This contains the files from the last successful remote refresh and ongoing uploads. This gets reset to just the
+     * last successful remote refresh state on successful remote refresh.
+     */
+    private final Set<String> latestUploadedFiles = ConcurrentCollections.newConcurrentSet();
+
+    /**
+     * Keeps the bytes lag computed so that we do not compute it for every request.
+     */
+    private volatile long bytesLag;
+
+    /**
+     * Holds count of consecutive failures until last success. Gets reset to zero if there is a success.
+     */
+    private final Streak failures = new Streak();
+
+    /**
+     * {@link org.opensearch.index.store.Store.StoreDirectory} level file transfer tracker, used to show download stats
+     */
+    private final DirectoryFileTransferTracker directoryFileTransferTracker;
+
+    public RemoteSegmentTransferTracker(
+        ShardId shardId,
+        DirectoryFileTransferTracker directoryFileTransferTracker,
+        int movingAverageWindowSize
+    ) {
+        super(shardId, movingAverageWindowSize);
+
+        logger = Loggers.getLogger(getClass(), shardId);
+        // Both the local refresh time and remote refresh time are set with current time to give consistent view of time lag when it arises.
+        long currentClockTimeMs = System.currentTimeMillis();
+        long currentTimeMs = System.nanoTime() / 1_000_000L;
+        localRefreshTimeMs = currentTimeMs;
+        remoteRefreshTimeMs = currentTimeMs;
+        localRefreshClockTimeMs = currentClockTimeMs;
+        remoteRefreshClockTimeMs = currentClockTimeMs;
+        this.directoryFileTransferTracker = directoryFileTransferTracker;
+    }
+
+    @Override
+    public void incrementTotalUploadsFailed() {
+        super.incrementTotalUploadsFailed();
+        failures.record(true);
+    }
+
+    @Override
+    public void incrementTotalUploadsSucceeded() {
+        super.incrementTotalUploadsSucceeded();
+        failures.record(false);
+    }
+
+    public long getLocalRefreshSeqNo() {
+        return localRefreshSeqNo;
+    }
+
+    // Visible for testing
+    void updateLocalRefreshSeqNo(long localRefreshSeqNo) {
+        assert localRefreshSeqNo >= this.localRefreshSeqNo : "newLocalRefreshSeqNo="
+            + localRefreshSeqNo
+            + " < "
+            + "currentLocalRefreshSeqNo="
+            + this.localRefreshSeqNo;
+        this.localRefreshSeqNo = localRefreshSeqNo;
+        computeRefreshSeqNoLag();
+    }
+
+    public long getLocalRefreshTimeMs() {
+        return localRefreshTimeMs;
+    }
+
+    public long getLocalRefreshClockTimeMs() {
+        return localRefreshClockTimeMs;
+    }
+
+    /**
+     * Updates the last refresh time and refresh seq no which is seen by local store.
+     */
+    public void updateLocalRefreshTimeAndSeqNo() {
+        updateLocalRefreshClockTimeMs(System.currentTimeMillis());
+        updateLocalRefreshTimeMs(System.nanoTime() / 1_000_000L);
+        updateLocalRefreshSeqNo(getLocalRefreshSeqNo() + 1);
+    }
+
+    // Visible for testing
+    void updateLocalRefreshTimeMs(long localRefreshTimeMs) {
+        assert localRefreshTimeMs >= this.localRefreshTimeMs : "newLocalRefreshTimeMs="
+            + localRefreshTimeMs
+            + " < "
+            + "currentLocalRefreshTimeMs="
+            + this.localRefreshTimeMs;
+        this.localRefreshTimeMs = localRefreshTimeMs;
+        computeTimeMsLag();
+    }
+
+    private void updateLocalRefreshClockTimeMs(long localRefreshClockTimeMs) {
+        this.localRefreshClockTimeMs = localRefreshClockTimeMs;
+    }
+
+    long getRemoteRefreshSeqNo() {
+        return remoteRefreshSeqNo;
+    }
+
+    public void updateRemoteRefreshSeqNo(long remoteRefreshSeqNo) {
+        assert remoteRefreshSeqNo >= this.remoteRefreshSeqNo : "newRemoteRefreshSeqNo="
+            + remoteRefreshSeqNo
+            + " < "
+            + "currentRemoteRefreshSeqNo="
+            + this.remoteRefreshSeqNo;
+        this.remoteRefreshSeqNo = remoteRefreshSeqNo;
+        computeRefreshSeqNoLag();
+    }
+
+    long getRemoteRefreshTimeMs() {
+        return remoteRefreshTimeMs;
+    }
+
+    long getRemoteRefreshClockTimeMs() {
+        return remoteRefreshClockTimeMs;
+    }
+
+    public void updateRemoteRefreshTimeMs(long remoteRefreshTimeMs) {
+        assert remoteRefreshTimeMs >= this.remoteRefreshTimeMs : "newRemoteRefreshTimeMs="
+            + remoteRefreshTimeMs
+            + " < "
+            + "currentRemoteRefreshTimeMs="
+            + this.remoteRefreshTimeMs;
+        this.remoteRefreshTimeMs = remoteRefreshTimeMs;
+        computeTimeMsLag();
+    }
+
+    public void updateRemoteRefreshClockTimeMs(long remoteRefreshClockTimeMs) {
+        this.remoteRefreshClockTimeMs = remoteRefreshClockTimeMs;
+    }
+
+    private void computeRefreshSeqNoLag() {
+        refreshSeqNoLag = localRefreshSeqNo - remoteRefreshSeqNo;
+    }
+
+    public long getRefreshSeqNoLag() {
+        return refreshSeqNoLag;
+    }
+
+    private void computeTimeMsLag() {
+        timeMsLag = localRefreshTimeMs - remoteRefreshTimeMs;
+    }
+
+    public long getTimeMsLag() {
+        return timeMsLag;
+    }
+
+    public long getBytesLag() {
+        return bytesLag;
+    }
+
+    public long getInflightUploadBytes() {
+        return uploadBytesStarted.get() - uploadBytesFailed.get() - uploadBytesSucceeded.get();
+    }
+
+    public long getInflightUploads() {
+        return totalUploadsStarted.get() - totalUploadsFailed.get() - totalUploadsSucceeded.get();
+    }
+
+    public long getRejectionCount() {
+        return rejectionCount.get();
+    }
+
+    void incrementRejectionCount() {
+        rejectionCount.incrementAndGet();
+    }
+
+    void incrementRejectionCount(String rejectionReason) {
+        rejectionCountMap.computeIfAbsent(rejectionReason, k -> new AtomicLong()).incrementAndGet();
+        incrementRejectionCount();
+    }
+
+    long getRejectionCount(String rejectionReason) {
+        return rejectionCountMap.get(rejectionReason).get();
+    }
+
+    public Map<String, Long> getLatestLocalFileNameLengthMap() {
+        return Collections.unmodifiableMap(latestLocalFileNameLengthMap);
+    }
+
+    /**
+     * Updates the latestLocalFileNameLengthMap by adding file name and it's size to the map. The method is given a function as an argument which is used for determining the file size (length in bytes). This method is also provided the collection of segment files which are the latest refresh local segment files. This method also removes the stale segment files from the map that are not part of the input segment files.
+     *
+     * @param segmentFiles     list of local refreshed segment files
+     * @param fileSizeFunction function is used to determine the file size in bytes
+     */
+    public void updateLatestLocalFileNameLengthMap(
+        Collection<String> segmentFiles,
+        CheckedFunction<String, Long, IOException> fileSizeFunction
+    ) {
+        logger.debug(
+            "segmentFilesPostRefresh={} latestLocalFileNamesBeforeMapUpdate={}",
+            segmentFiles,
+            latestLocalFileNameLengthMap.keySet()
+        );
+        // Update the map
+        segmentFiles.stream()
+            .filter(file -> EXCLUDE_FILES.contains(file) == false)
+            .filter(file -> latestLocalFileNameLengthMap.containsKey(file) == false || latestLocalFileNameLengthMap.get(file) == 0)
+            .forEach(file -> {
+                long fileSize = 0;
+                try {
+                    fileSize = fileSizeFunction.apply(file);
+                } catch (IOException e) {
+                    logger.warn(new ParameterizedMessage("Exception while reading the fileLength of file={}", file), e);
+                }
+                latestLocalFileNameLengthMap.put(file, fileSize);
+            });
+        Set<String> fileSet = new HashSet<>(segmentFiles);
+        // Remove keys from the fileSizeMap that do not exist in the latest segment files
+        latestLocalFileNameLengthMap.entrySet().removeIf(entry -> fileSet.contains(entry.getKey()) == false);
+        computeBytesLag();
+    }
+
+    public void addToLatestUploadedFiles(String file) {
+        this.latestUploadedFiles.add(file);
+        computeBytesLag();
+    }
+
+    public void setLatestUploadedFiles(Set<String> files) {
+        this.latestUploadedFiles.clear();
+        this.latestUploadedFiles.addAll(files);
+        computeBytesLag();
+    }
+
+    private void computeBytesLag() {
+        if (latestLocalFileNameLengthMap.isEmpty()) {
+            return;
+        }
+        Set<String> filesNotYetUploaded = latestLocalFileNameLengthMap.keySet()
+            .stream()
+            .filter(f -> !latestUploadedFiles.contains(f))
+            .collect(Collectors.toSet());
+        this.bytesLag = filesNotYetUploaded.stream().map(latestLocalFileNameLengthMap::get).mapToLong(Long::longValue).sum();
+    }
+
+    int getConsecutiveFailureCount() {
+        return failures.length();
+    }
+
+    public DirectoryFileTransferTracker getDirectoryFileTransferTracker() {
+        return directoryFileTransferTracker;
+    }
+
+    public RemoteSegmentTransferTracker.Stats stats() {
+        return new RemoteSegmentTransferTracker.Stats(
+            shardId,
+            localRefreshClockTimeMs,
+            remoteRefreshClockTimeMs,
+            timeMsLag,
+            localRefreshSeqNo,
+            remoteRefreshSeqNo,
+            uploadBytesStarted.get(),
+            uploadBytesSucceeded.get(),
+            uploadBytesFailed.get(),
+            totalUploadsStarted.get(),
+            totalUploadsSucceeded.get(),
+            totalUploadsFailed.get(),
+            rejectionCount.get(),
+            failures.length(),
+            lastSuccessfulRemoteRefreshBytes,
+            uploadBytesMovingAverageReference.get().getAverage(),
+            uploadBytesPerSecMovingAverageReference.get().getAverage(),
+            uploadTimeMsMovingAverageReference.get().getAverage(),
+            getBytesLag(),
+            totalUploadTimeInMillis.get(),
+            directoryFileTransferTracker.stats()
+        );
+    }
+
+    /**
+     * Represents the tracker's state as seen in the stats API.
+     *
+     * @opensearch.internal
+     */
+    public static class Stats implements Writeable {
+
+        public final ShardId shardId;
+        public final long localRefreshClockTimeMs;
+        public final long remoteRefreshClockTimeMs;
+        public final long refreshTimeLagMs;
+        public final long localRefreshNumber;
+        public final long remoteRefreshNumber;
+        public final long uploadBytesStarted;
+        public final long uploadBytesFailed;
+        public final long uploadBytesSucceeded;
+        public final long totalUploadsStarted;
+        public final long totalUploadsFailed;
+        public final long totalUploadsSucceeded;
+        public final long rejectionCount;
+        public final long consecutiveFailuresCount;
+        public final long lastSuccessfulRemoteRefreshBytes;
+        public final double uploadBytesMovingAverage;
+        public final double uploadBytesPerSecMovingAverage;
+        public final long totalUploadTimeInMs;
+        public final double uploadTimeMovingAverage;
+        public final long bytesLag;
+        public final DirectoryFileTransferTracker.Stats directoryFileTransferTrackerStats;
+
+        public Stats(
+            ShardId shardId,
+            long localRefreshClockTimeMs,
+            long remoteRefreshClockTimeMs,
+            long refreshTimeLagMs,
+            long localRefreshNumber,
+            long remoteRefreshNumber,
+            long uploadBytesStarted,
+            long uploadBytesSucceeded,
+            long uploadBytesFailed,
+            long totalUploadsStarted,
+            long totalUploadsSucceeded,
+            long totalUploadsFailed,
+            long rejectionCount,
+            long consecutiveFailuresCount,
+            long lastSuccessfulRemoteRefreshBytes,
+            double uploadBytesMovingAverage,
+            double uploadBytesPerSecMovingAverage,
+            double uploadTimeMovingAverage,
+            long bytesLag,
+            long totalUploadTimeInMs,
+            DirectoryFileTransferTracker.Stats directoryFileTransferTrackerStats
+        ) {
+            this.shardId = shardId;
+            this.localRefreshClockTimeMs = localRefreshClockTimeMs;
+            this.remoteRefreshClockTimeMs = remoteRefreshClockTimeMs;
+            this.refreshTimeLagMs = refreshTimeLagMs;
+            this.localRefreshNumber = localRefreshNumber;
+            this.remoteRefreshNumber = remoteRefreshNumber;
+            this.uploadBytesStarted = uploadBytesStarted;
+            this.uploadBytesFailed = uploadBytesFailed;
+            this.uploadBytesSucceeded = uploadBytesSucceeded;
+            this.totalUploadsStarted = totalUploadsStarted;
+            this.totalUploadsFailed = totalUploadsFailed;
+            this.totalUploadsSucceeded = totalUploadsSucceeded;
+            this.rejectionCount = rejectionCount;
+            this.consecutiveFailuresCount = consecutiveFailuresCount;
+            this.lastSuccessfulRemoteRefreshBytes = lastSuccessfulRemoteRefreshBytes;
+            this.uploadBytesMovingAverage = uploadBytesMovingAverage;
+            this.uploadBytesPerSecMovingAverage = uploadBytesPerSecMovingAverage;
+            this.uploadTimeMovingAverage = uploadTimeMovingAverage;
+            this.bytesLag = bytesLag;
+            this.totalUploadTimeInMs = totalUploadTimeInMs;
+            this.directoryFileTransferTrackerStats = directoryFileTransferTrackerStats;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            try {
+                this.shardId = new ShardId(in);
+                this.localRefreshClockTimeMs = in.readLong();
+                this.remoteRefreshClockTimeMs = in.readLong();
+                this.refreshTimeLagMs = in.readLong();
+                this.localRefreshNumber = in.readLong();
+                this.remoteRefreshNumber = in.readLong();
+                this.uploadBytesStarted = in.readLong();
+                this.uploadBytesFailed = in.readLong();
+                this.uploadBytesSucceeded = in.readLong();
+                this.totalUploadsStarted = in.readLong();
+                this.totalUploadsFailed = in.readLong();
+                this.totalUploadsSucceeded = in.readLong();
+                this.rejectionCount = in.readLong();
+                this.consecutiveFailuresCount = in.readLong();
+                this.lastSuccessfulRemoteRefreshBytes = in.readLong();
+                this.uploadBytesMovingAverage = in.readDouble();
+                this.uploadBytesPerSecMovingAverage = in.readDouble();
+                this.uploadTimeMovingAverage = in.readDouble();
+                this.bytesLag = in.readLong();
+                this.totalUploadTimeInMs = in.readLong();
+                this.directoryFileTransferTrackerStats = in.readOptionalWriteable(DirectoryFileTransferTracker.Stats::new);
+            } catch (IOException e) {
+                throw e;
+            }
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            shardId.writeTo(out);
+            out.writeLong(localRefreshClockTimeMs);
+            out.writeLong(remoteRefreshClockTimeMs);
+            out.writeLong(refreshTimeLagMs);
+            out.writeLong(localRefreshNumber);
+            out.writeLong(remoteRefreshNumber);
+            out.writeLong(uploadBytesStarted);
+            out.writeLong(uploadBytesFailed);
+            out.writeLong(uploadBytesSucceeded);
+            out.writeLong(totalUploadsStarted);
+            out.writeLong(totalUploadsFailed);
+            out.writeLong(totalUploadsSucceeded);
+            out.writeLong(rejectionCount);
+            out.writeLong(consecutiveFailuresCount);
+            out.writeLong(lastSuccessfulRemoteRefreshBytes);
+            out.writeDouble(uploadBytesMovingAverage);
+            out.writeDouble(uploadBytesPerSecMovingAverage);
+            out.writeDouble(uploadTimeMovingAverage);
+            out.writeLong(bytesLag);
+            out.writeLong(totalUploadTimeInMs);
+            out.writeOptionalWriteable(directoryFileTransferTrackerStats);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            Stats other = (Stats) obj;
+
+            return this.shardId.toString().equals(other.shardId.toString())
+                && this.localRefreshClockTimeMs == other.localRefreshClockTimeMs
+                && this.remoteRefreshClockTimeMs == other.remoteRefreshClockTimeMs
+                && this.refreshTimeLagMs == other.refreshTimeLagMs
+                && this.localRefreshNumber == other.localRefreshNumber
+                && this.remoteRefreshNumber == other.remoteRefreshNumber
+                && this.uploadBytesStarted == other.uploadBytesStarted
+                && this.uploadBytesFailed == other.uploadBytesFailed
+                && this.uploadBytesSucceeded == other.uploadBytesSucceeded
+                && this.totalUploadsStarted == other.totalUploadsStarted
+                && this.totalUploadsFailed == other.totalUploadsFailed
+                && this.totalUploadsSucceeded == other.totalUploadsSucceeded
+                && this.rejectionCount == other.rejectionCount
+                && this.consecutiveFailuresCount == other.consecutiveFailuresCount
+                && this.lastSuccessfulRemoteRefreshBytes == other.lastSuccessfulRemoteRefreshBytes
+                && Double.compare(this.uploadBytesMovingAverage, other.uploadBytesMovingAverage) == 0
+                && Double.compare(this.uploadBytesPerSecMovingAverage, other.uploadBytesPerSecMovingAverage) == 0
+                && Double.compare(this.uploadTimeMovingAverage, other.uploadTimeMovingAverage) == 0
+                && this.bytesLag == other.bytesLag
+                && this.totalUploadTimeInMs == other.totalUploadTimeInMs
+                && this.directoryFileTransferTrackerStats.equals(other.directoryFileTransferTrackerStats);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(
+                shardId,
+                localRefreshClockTimeMs,
+                remoteRefreshClockTimeMs,
+                refreshTimeLagMs,
+                localRefreshNumber,
+                remoteRefreshNumber,
+                uploadBytesStarted,
+                uploadBytesFailed,
+                uploadBytesSucceeded,
+                totalUploadsStarted,
+                totalUploadsFailed,
+                totalUploadsSucceeded,
+                rejectionCount,
+                consecutiveFailuresCount,
+                lastSuccessfulRemoteRefreshBytes,
+                uploadBytesMovingAverage,
+                uploadBytesPerSecMovingAverage,
+                uploadTimeMovingAverage,
+                bytesLag,
+                totalUploadTimeInMs,
+                directoryFileTransferTrackerStats
+            );
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureService.java b/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureService.java
new file mode 100644
index 0000000000000..2920b33921869
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureService.java
@@ -0,0 +1,249 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Service used to validate if the incoming indexing request should be rejected based on the {@link RemoteSegmentTransferTracker}.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStorePressureService {
+
+    private static final Logger logger = LogManager.getLogger(RemoteStorePressureService.class);
+
+    /**
+     * Remote refresh segment pressure settings which is used for creation of the backpressure tracker and as well as rejection.
+     */
+    private final RemoteStorePressureSettings pressureSettings;
+
+    private final List<LagValidator> lagValidators;
+
+    private final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    @Inject
+    public RemoteStorePressureService(
+        ClusterService clusterService,
+        Settings settings,
+        RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
+    ) {
+        pressureSettings = new RemoteStorePressureSettings(clusterService, settings, this);
+        lagValidators = Arrays.asList(
+            new ConsecutiveFailureValidator(pressureSettings),
+            new BytesLagValidator(pressureSettings),
+            new TimeLagValidator(pressureSettings)
+        );
+        this.remoteStoreStatsTrackerFactory = remoteStoreStatsTrackerFactory;
+    }
+
+    /**
+     * Check if remote refresh segments backpressure is enabled. This is backed by a cluster level setting.
+     *
+     * @return true if enabled, else false.
+     */
+    public boolean isSegmentsUploadBackpressureEnabled() {
+        return pressureSettings.isRemoteRefreshSegmentPressureEnabled();
+    }
+
+    /**
+     * Validates if segments are lagging more than the limits. If yes, it would lead to rejections of the requests.
+     *
+     * @param shardId shardId for which the validation needs to be done.
+     */
+    public void validateSegmentsUploadLag(ShardId shardId) {
+        RemoteSegmentTransferTracker remoteSegmentTransferTracker = remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId);
+        // condition 1 - This will be null for non-remote backed indexes
+        // condition 2 - This will be zero if the remote store is
+        if (remoteSegmentTransferTracker == null || remoteSegmentTransferTracker.getRefreshSeqNoLag() == 0) {
+            return;
+        }
+
+        for (LagValidator lagValidator : lagValidators) {
+            if (lagValidator.validate(remoteSegmentTransferTracker, shardId) == false) {
+                remoteSegmentTransferTracker.incrementRejectionCount(lagValidator.name());
+                throw new OpenSearchRejectedExecutionException(lagValidator.rejectionMessage(remoteSegmentTransferTracker, shardId));
+            }
+        }
+    }
+
+    /**
+     * Abstract class for validating if lag is acceptable or not.
+     *
+     * @opensearch.internal
+     */
+    private static abstract class LagValidator {
+
+        final RemoteStorePressureSettings pressureSettings;
+
+        private LagValidator(RemoteStorePressureSettings pressureSettings) {
+            this.pressureSettings = pressureSettings;
+        }
+
+        /**
+         * Validates the lag and returns value accordingly.
+         *
+         * @param pressureTracker tracker which holds information about the shard.
+         * @param shardId         shard id of the {@code IndexShard} currently being validated.
+         * @return true if successfully validated that lag is acceptable.
+         */
+        abstract boolean validate(RemoteSegmentTransferTracker pressureTracker, ShardId shardId);
+
+        /**
+         * Returns the name of the lag validator.
+         *
+         * @return the name using class name.
+         */
+        abstract String name();
+
+        abstract String rejectionMessage(RemoteSegmentTransferTracker pressureTracker, ShardId shardId);
+    }
+
+    /**
+     * Check if the remote store is lagging more than the upload bytes average multiplied by a variance factor
+     *
+     * @opensearch.internal
+     */
+    private static class BytesLagValidator extends LagValidator {
+
+        private static final String NAME = "bytes_lag";
+
+        private BytesLagValidator(RemoteStorePressureSettings pressureSettings) {
+            super(pressureSettings);
+        }
+
+        @Override
+        public boolean validate(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            if (pressureTracker.getRefreshSeqNoLag() <= 1) {
+                return true;
+            }
+            if (pressureTracker.isUploadBytesMovingAverageReady() == false) {
+                logger.trace("upload bytes moving average is not ready");
+                return true;
+            }
+            double dynamicBytesLagThreshold = pressureTracker.getUploadBytesMovingAverage() * pressureSettings.getBytesLagVarianceFactor();
+            long bytesLag = pressureTracker.getBytesLag();
+            return bytesLag <= dynamicBytesLagThreshold;
+        }
+
+        @Override
+        public String rejectionMessage(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            double dynamicBytesLagThreshold = pressureTracker.getUploadBytesMovingAverage() * pressureSettings.getBytesLagVarianceFactor();
+            return String.format(
+                Locale.ROOT,
+                "rejected execution on primary shard:%s due to remote segments lagging behind local segments."
+                    + "bytes_lag:%s dynamic_bytes_lag_threshold:%s",
+                shardId,
+                pressureTracker.getBytesLag(),
+                dynamicBytesLagThreshold
+            );
+        }
+
+        @Override
+        String name() {
+            return NAME;
+        }
+    }
+
+    /**
+     * Check if the remote store is lagging more than the upload time average multiplied by a variance factor
+     *
+     * @opensearch.internal
+     */
+    private static class TimeLagValidator extends LagValidator {
+
+        private static final String NAME = "time_lag";
+
+        private TimeLagValidator(RemoteStorePressureSettings pressureSettings) {
+            super(pressureSettings);
+        }
+
+        @Override
+        public boolean validate(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            if (pressureTracker.getRefreshSeqNoLag() <= 1) {
+                return true;
+            }
+            if (pressureTracker.isUploadTimeMovingAverageReady() == false) {
+                logger.trace("upload time moving average is not ready");
+                return true;
+            }
+            long timeLag = pressureTracker.getTimeMsLag();
+            double dynamicTimeLagThreshold = pressureTracker.getUploadTimeMovingAverage() * pressureSettings
+                .getUploadTimeLagVarianceFactor();
+            return timeLag <= dynamicTimeLagThreshold;
+        }
+
+        @Override
+        public String rejectionMessage(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            double dynamicTimeLagThreshold = pressureTracker.getUploadTimeMovingAverage() * pressureSettings
+                .getUploadTimeLagVarianceFactor();
+            return String.format(
+                Locale.ROOT,
+                "rejected execution on primary shard:%s due to remote segments lagging behind local segments."
+                    + "time_lag:%s ms dynamic_time_lag_threshold:%s ms",
+                shardId,
+                pressureTracker.getTimeMsLag(),
+                dynamicTimeLagThreshold
+            );
+        }
+
+        @Override
+        String name() {
+            return NAME;
+        }
+    }
+
+    /**
+     * Check if consecutive failure limit has been breached
+     *
+     * @opensearch.internal
+     */
+    private static class ConsecutiveFailureValidator extends LagValidator {
+
+        private static final String NAME = "consecutive_failures_lag";
+
+        private ConsecutiveFailureValidator(RemoteStorePressureSettings pressureSettings) {
+            super(pressureSettings);
+        }
+
+        @Override
+        public boolean validate(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            int failureStreakCount = pressureTracker.getConsecutiveFailureCount();
+            int minConsecutiveFailureThreshold = pressureSettings.getMinConsecutiveFailuresLimit();
+            return failureStreakCount <= minConsecutiveFailureThreshold;
+        }
+
+        @Override
+        public String rejectionMessage(RemoteSegmentTransferTracker pressureTracker, ShardId shardId) {
+            return String.format(
+                Locale.ROOT,
+                "rejected execution on primary shard:%s due to remote segments lagging behind local segments."
+                    + "failure_streak_count:%s min_consecutive_failure_threshold:%s",
+                shardId,
+                pressureTracker.getConsecutiveFailureCount(),
+                pressureSettings.getMinConsecutiveFailuresLimit()
+            );
+        }
+
+        @Override
+        String name() {
+            return NAME;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureSettings.java b/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureSettings.java
new file mode 100644
index 0000000000000..e66aa3444c214
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteStorePressureSettings.java
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+
+/**
+ * Settings related to back pressure on account of segments upload failures / lags.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStorePressureSettings {
+
+    static class Defaults {
+        private static final double BYTES_LAG_VARIANCE_FACTOR = 10.0;
+        private static final double UPLOAD_TIME_LAG_VARIANCE_FACTOR = 10.0;
+        private static final double VARIANCE_FACTOR_MIN_VALUE = 1.0;
+        private static final int MIN_CONSECUTIVE_FAILURES_LIMIT = 5;
+        private static final int MIN_CONSECUTIVE_FAILURES_LIMIT_MIN_VALUE = 1;
+    }
+
+    public static final Setting<Boolean> REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED = Setting.boolSetting(
+        "remote_store.segment.pressure.enabled",
+        true,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Double> BYTES_LAG_VARIANCE_FACTOR = Setting.doubleSetting(
+        "remote_store.segment.pressure.bytes_lag.variance_factor",
+        Defaults.BYTES_LAG_VARIANCE_FACTOR,
+        Defaults.VARIANCE_FACTOR_MIN_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Double> UPLOAD_TIME_LAG_VARIANCE_FACTOR = Setting.doubleSetting(
+        "remote_store.segment.pressure.time_lag.variance_factor",
+        Defaults.UPLOAD_TIME_LAG_VARIANCE_FACTOR,
+        Defaults.VARIANCE_FACTOR_MIN_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Integer> MIN_CONSECUTIVE_FAILURES_LIMIT = Setting.intSetting(
+        "remote_store.segment.pressure.consecutive_failures.limit",
+        Defaults.MIN_CONSECUTIVE_FAILURES_LIMIT,
+        Defaults.MIN_CONSECUTIVE_FAILURES_LIMIT_MIN_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private volatile boolean remoteRefreshSegmentPressureEnabled;
+
+    private volatile long minRefreshSeqNoLagLimit;
+
+    private volatile double bytesLagVarianceFactor;
+
+    private volatile double uploadTimeLagVarianceFactor;
+
+    private volatile int minConsecutiveFailuresLimit;
+
+    public RemoteStorePressureSettings(
+        ClusterService clusterService,
+        Settings settings,
+        RemoteStorePressureService remoteStorePressureService
+    ) {
+        ClusterSettings clusterSettings = clusterService.getClusterSettings();
+
+        this.remoteRefreshSegmentPressureEnabled = REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED, this::setRemoteRefreshSegmentPressureEnabled);
+
+        this.bytesLagVarianceFactor = BYTES_LAG_VARIANCE_FACTOR.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(BYTES_LAG_VARIANCE_FACTOR, this::setBytesLagVarianceFactor);
+
+        this.uploadTimeLagVarianceFactor = UPLOAD_TIME_LAG_VARIANCE_FACTOR.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(UPLOAD_TIME_LAG_VARIANCE_FACTOR, this::setUploadTimeLagVarianceFactor);
+
+        this.minConsecutiveFailuresLimit = MIN_CONSECUTIVE_FAILURES_LIMIT.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MIN_CONSECUTIVE_FAILURES_LIMIT, this::setMinConsecutiveFailuresLimit);
+    }
+
+    boolean isRemoteRefreshSegmentPressureEnabled() {
+        return remoteRefreshSegmentPressureEnabled;
+    }
+
+    private void setRemoteRefreshSegmentPressureEnabled(boolean remoteRefreshSegmentPressureEnabled) {
+        this.remoteRefreshSegmentPressureEnabled = remoteRefreshSegmentPressureEnabled;
+    }
+
+    long getMinRefreshSeqNoLagLimit() {
+        return minRefreshSeqNoLagLimit;
+    }
+
+    private void setMinRefreshSeqNoLagLimit(long minRefreshSeqNoLagLimit) {
+        this.minRefreshSeqNoLagLimit = minRefreshSeqNoLagLimit;
+    }
+
+    double getBytesLagVarianceFactor() {
+        return bytesLagVarianceFactor;
+    }
+
+    private void setBytesLagVarianceFactor(double bytesLagVarianceFactor) {
+        this.bytesLagVarianceFactor = bytesLagVarianceFactor;
+    }
+
+    double getUploadTimeLagVarianceFactor() {
+        return uploadTimeLagVarianceFactor;
+    }
+
+    private void setUploadTimeLagVarianceFactor(double uploadTimeLagVarianceFactor) {
+        this.uploadTimeLagVarianceFactor = uploadTimeLagVarianceFactor;
+    }
+
+    int getMinConsecutiveFailuresLimit() {
+        return minConsecutiveFailuresLimit;
+    }
+
+    private void setMinConsecutiveFailuresLimit(int minConsecutiveFailuresLimit) {
+        this.minConsecutiveFailuresLimit = minConsecutiveFailuresLimit;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactory.java b/server/src/main/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactory.java
new file mode 100644
index 0000000000000..6058fcc7345d2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactory.java
@@ -0,0 +1,115 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexEventListener;
+import org.opensearch.index.shard.IndexShard;
+
+import java.util.Map;
+
+/**
+ * Factory to manage stats trackers for Remote Store operations
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreStatsTrackerFactory implements IndexEventListener {
+    static class Defaults {
+        static final int MOVING_AVERAGE_WINDOW_SIZE = 20;
+        static final int MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE = 5;
+    }
+
+    public static final Setting<Integer> MOVING_AVERAGE_WINDOW_SIZE = Setting.intSetting(
+        "remote_store.moving_average_window_size",
+        Defaults.MOVING_AVERAGE_WINDOW_SIZE,
+        Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private static final Logger logger = LogManager.getLogger(RemoteStoreStatsTrackerFactory.class);
+
+    /**
+     * Number of data points to consider for a moving average statistic
+     */
+    private volatile int movingAverageWindowSize;
+
+    /**
+     * Keeps map of remote-backed index shards and their corresponding stats tracker.
+     */
+    private final Map<ShardId, RemoteSegmentTransferTracker> remoteSegmentTrackerMap = ConcurrentCollections.newConcurrentMap();
+
+    /**
+     * Keeps map of remote-backed index shards and their corresponding stats tracker.
+     */
+    private final Map<ShardId, RemoteTranslogTransferTracker> remoteTranslogTrackerMap = ConcurrentCollections.newConcurrentMap();
+
+    public RemoteStoreStatsTrackerFactory(ClusterService clusterService, Settings settings) {
+        ClusterSettings clusterSettings = clusterService.getClusterSettings();
+
+        this.movingAverageWindowSize = MOVING_AVERAGE_WINDOW_SIZE.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(MOVING_AVERAGE_WINDOW_SIZE, this::updateMovingAverageWindowSize);
+    }
+
+    @Override
+    public void afterIndexShardCreated(IndexShard indexShard) {
+        if (indexShard.indexSettings().isRemoteStoreEnabled() == false) {
+            return;
+        }
+        ShardId shardId = indexShard.shardId();
+        remoteSegmentTrackerMap.put(
+            shardId,
+            new RemoteSegmentTransferTracker(shardId, indexShard.store().getDirectoryFileTransferTracker(), movingAverageWindowSize)
+        );
+        logger.trace("Created RemoteSegmentTransferTracker for shardId={}", shardId);
+        remoteTranslogTrackerMap.put(shardId, new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize));
+        logger.trace("Created RemoteTranslogTransferTracker for shardId={}", shardId);
+    }
+
+    @Override
+    public void afterIndexShardClosed(ShardId shardId, IndexShard indexShard, Settings indexSettings) {
+        RemoteSegmentTransferTracker remoteSegmentTransferTracker = remoteSegmentTrackerMap.remove(shardId);
+        if (remoteSegmentTransferTracker != null) {
+            logger.trace("Deleted RemoteSegmentTransferTracker for shardId={}", shardId);
+        }
+
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = remoteTranslogTrackerMap.remove(shardId);
+        if (remoteTranslogTransferTracker != null) {
+            logger.trace("Deleted RemoteTranslogTransferTracker for shardId={}", shardId);
+        }
+    }
+
+    private void updateMovingAverageWindowSize(int updatedSize) {
+        remoteSegmentTrackerMap.values().forEach(tracker -> tracker.updateMovingAverageWindowSize(updatedSize));
+        remoteTranslogTrackerMap.values().forEach(tracker -> tracker.updateMovingAverageWindowSize(updatedSize));
+
+        // Update movingAverageWindowSize only if the trackers were successfully updated
+        movingAverageWindowSize = updatedSize;
+    }
+
+    public RemoteSegmentTransferTracker getRemoteSegmentTransferTracker(ShardId shardId) {
+        return remoteSegmentTrackerMap.get(shardId);
+    }
+
+    public RemoteTranslogTransferTracker getRemoteTranslogTransferTracker(ShardId shardId) {
+        return remoteTranslogTrackerMap.get(shardId);
+    }
+
+    // visible for testing
+    int getMovingAverageWindowSize() {
+        return movingAverageWindowSize;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java b/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java
new file mode 100644
index 0000000000000..0ca9e0209c5ec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java
@@ -0,0 +1,105 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.common.collect.Tuple;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * Utils for remote store
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreUtils {
+    public static final int LONG_MAX_LENGTH = String.valueOf(Long.MAX_VALUE).length();
+
+    /**
+     * This method subtracts given numbers from Long.MAX_VALUE and returns a string representation of the result.
+     * The resultant string is guaranteed to be of the same length that of Long.MAX_VALUE. If shorter, we add left padding
+     * of 0s to the string.
+     * @param num number to get the inverted long string for
+     * @return String value of Long.MAX_VALUE - num
+     */
+    public static String invertLong(long num) {
+        if (num < 0) {
+            throw new IllegalArgumentException("Negative long values are not allowed");
+        }
+        String invertedLong = String.valueOf(Long.MAX_VALUE - num);
+        char[] characterArray = new char[LONG_MAX_LENGTH - invertedLong.length()];
+        Arrays.fill(characterArray, '0');
+
+        return new String(characterArray) + invertedLong;
+    }
+
+    /**
+     * This method converts the given string into long and subtracts it from Long.MAX_VALUE
+     * @param str long in string format to be inverted
+     * @return long value of the invert result
+     */
+    public static long invertLong(String str) {
+        long num = Long.parseLong(str);
+        if (num < 0) {
+            throw new IllegalArgumentException("Strings representing negative long values are not allowed");
+        }
+        return Long.MAX_VALUE - num;
+    }
+
+    /**
+     * Extracts the segment name from the provided segment file name
+     * @param filename Segment file name to parse
+     * @return Name of the segment that the segment file belongs to
+     */
+    public static String getSegmentName(String filename) {
+        // Segment file names follow patterns like "_0.cfe" or "_0_1_Lucene90_0.dvm".
+        // Here, the segment name is "_0", which is the set of characters
+        // starting with "_" until the next "_" or first ".".
+        int endIdx = filename.indexOf('_', 1);
+        if (endIdx == -1) {
+            endIdx = filename.indexOf('.');
+        }
+
+        if (endIdx == -1) {
+            throw new IllegalArgumentException("Unable to infer segment name for segment file " + filename);
+        }
+
+        return filename.substring(0, endIdx);
+    }
+
+    /**
+     *
+     * @param mdFiles List of segment/translog metadata files
+     * @param fn Function to extract PrimaryTerm_Generation and Node Id from metadata file name .
+     *          fn returns null if node id is not part of the file name
+     */
+    static public void verifyNoMultipleWriters(List<String> mdFiles, Function<String, Tuple<String, String>> fn) {
+        Map<String, String> nodesByPrimaryTermAndGen = new HashMap<>();
+        mdFiles.forEach(mdFile -> {
+            Tuple<String, String> nodeIdByPrimaryTermAndGen = fn.apply(mdFile);
+            if (nodeIdByPrimaryTermAndGen != null) {
+                if (nodesByPrimaryTermAndGen.containsKey(nodeIdByPrimaryTermAndGen.v1())
+                    && (!nodesByPrimaryTermAndGen.get(nodeIdByPrimaryTermAndGen.v1()).equals(nodeIdByPrimaryTermAndGen.v2()))) {
+                    throw new IllegalStateException(
+                        "Multiple metadata files from different nodes"
+                            + nodeIdByPrimaryTermAndGen.v1()
+                            + " and "
+                            + nodeIdByPrimaryTermAndGen.v2()
+                            + "having same primary term and generations detected"
+                    );
+                }
+                nodesByPrimaryTermAndGen.put(nodeIdByPrimaryTermAndGen.v1(), nodeIdByPrimaryTermAndGen.v2());
+            }
+        });
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteTransferTracker.java b/server/src/main/java/org/opensearch/index/remote/RemoteTransferTracker.java
new file mode 100644
index 0000000000000..cbae4931b7001
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteTransferTracker.java
@@ -0,0 +1,269 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.common.util.MovingAverage;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Base class for remote store stats trackers
+ *
+ * @opensearch.internal
+ */
+public abstract class RemoteTransferTracker {
+    /**
+     * The shard that this tracker is associated with
+     */
+    protected final ShardId shardId;
+
+    /**
+     * Total time spent on Remote Store uploads.
+     */
+    protected final AtomicLong totalUploadTimeInMillis;
+
+    /**
+     * Total number of Remote Store uploads that have been started.
+     */
+    protected final AtomicLong totalUploadsStarted;
+
+    /**
+     * Total number of Remote Store uploads that have failed.
+     */
+    protected final AtomicLong totalUploadsFailed;
+
+    /**
+     * Total number of Remote Store that have been successful.
+     */
+    protected final AtomicLong totalUploadsSucceeded;
+
+    /**
+     * Total number of byte uploads to Remote Store that have been started.
+     */
+    protected final AtomicLong uploadBytesStarted;
+
+    /**
+     * Total number of byte uploads to Remote Store that have failed.
+     */
+    protected final AtomicLong uploadBytesFailed;
+
+    /**
+     * Total number of byte uploads to Remote Store that have been successful.
+     */
+    protected final AtomicLong uploadBytesSucceeded;
+
+    /**
+     * Provides moving average over the last N total size in bytes of files uploaded as part of Remote Store upload.
+     * N is window size. Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    protected final AtomicReference<MovingAverage> uploadBytesMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    protected final Object uploadBytesMutex;
+
+    /**
+     * Provides moving average over the last N upload speed (in bytes/s) of files uploaded as part of Remote Store upload.
+     * N is window size. Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    protected final AtomicReference<MovingAverage> uploadBytesPerSecMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    protected final Object uploadBytesPerSecMutex;
+
+    /**
+     * Provides moving average over the last N overall upload time (in nanos) as part of Remote Store upload. N is window size.
+     * Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    protected final AtomicReference<MovingAverage> uploadTimeMsMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    protected final Object uploadTimeMsMutex;
+
+    public RemoteTransferTracker(ShardId shardId, int movingAverageWindowSize) {
+        this.shardId = shardId;
+        totalUploadTimeInMillis = new AtomicLong(0);
+        totalUploadsStarted = new AtomicLong(0);
+        totalUploadsFailed = new AtomicLong(0);
+        totalUploadsSucceeded = new AtomicLong(0);
+        uploadBytesStarted = new AtomicLong(0);
+        uploadBytesFailed = new AtomicLong(0);
+        uploadBytesSucceeded = new AtomicLong(0);
+        uploadBytesMutex = new Object();
+        uploadBytesMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+        uploadBytesPerSecMutex = new Object();
+        uploadBytesPerSecMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+        uploadTimeMsMutex = new Object();
+        uploadTimeMsMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+    }
+
+    ShardId getShardId() {
+        return shardId;
+    }
+
+    public long getTotalUploadTimeInMillis() {
+        return totalUploadTimeInMillis.get();
+    }
+
+    public void addUploadTimeInMillis(long duration) {
+        totalUploadTimeInMillis.addAndGet(duration);
+    }
+
+    public long getTotalUploadsStarted() {
+        return totalUploadsStarted.get();
+    }
+
+    public long getTotalUploadsFailed() {
+        return totalUploadsFailed.get();
+    }
+
+    public long getTotalUploadsSucceeded() {
+        return totalUploadsSucceeded.get();
+    }
+
+    public void incrementTotalUploadsStarted() {
+        totalUploadsStarted.addAndGet(1);
+    }
+
+    public void incrementTotalUploadsFailed() {
+        checkTotal(totalUploadsStarted.get(), totalUploadsFailed.get(), totalUploadsSucceeded.get(), 1);
+        totalUploadsFailed.addAndGet(1);
+    }
+
+    public void incrementTotalUploadsSucceeded() {
+        checkTotal(totalUploadsStarted.get(), totalUploadsFailed.get(), totalUploadsSucceeded.get(), 1);
+        totalUploadsSucceeded.addAndGet(1);
+    }
+
+    public long getUploadBytesStarted() {
+        return uploadBytesStarted.get();
+    }
+
+    public long getUploadBytesFailed() {
+        return uploadBytesFailed.get();
+    }
+
+    public long getUploadBytesSucceeded() {
+        return uploadBytesSucceeded.get();
+    }
+
+    public void addUploadBytesStarted(long count) {
+        uploadBytesStarted.addAndGet(count);
+    }
+
+    public void addUploadBytesFailed(long count) {
+        checkTotal(uploadBytesStarted.get(), uploadBytesFailed.get(), uploadBytesSucceeded.get(), count);
+        uploadBytesFailed.addAndGet(count);
+    }
+
+    public void addUploadBytesSucceeded(long count) {
+        checkTotal(uploadBytesStarted.get(), uploadBytesFailed.get(), uploadBytesSucceeded.get(), count);
+        uploadBytesSucceeded.addAndGet(count);
+    }
+
+    boolean isUploadBytesMovingAverageReady() {
+        return uploadBytesMovingAverageReference.get().isReady();
+    }
+
+    double getUploadBytesMovingAverage() {
+        return uploadBytesMovingAverageReference.get().getAverage();
+    }
+
+    public void updateUploadBytesMovingAverage(long count) {
+        updateMovingAverage(count, uploadBytesMutex, uploadBytesMovingAverageReference);
+    }
+
+    boolean isUploadBytesPerSecMovingAverageReady() {
+        return uploadBytesPerSecMovingAverageReference.get().isReady();
+    }
+
+    double getUploadBytesPerSecMovingAverage() {
+        return uploadBytesPerSecMovingAverageReference.get().getAverage();
+    }
+
+    public void updateUploadBytesPerSecMovingAverage(long speed) {
+        updateMovingAverage(speed, uploadBytesPerSecMutex, uploadBytesPerSecMovingAverageReference);
+    }
+
+    boolean isUploadTimeMovingAverageReady() {
+        return uploadTimeMsMovingAverageReference.get().isReady();
+    }
+
+    double getUploadTimeMovingAverage() {
+        return uploadTimeMsMovingAverageReference.get().getAverage();
+    }
+
+    public void updateUploadTimeMovingAverage(long duration) {
+        updateMovingAverage(duration, uploadTimeMsMutex, uploadTimeMsMovingAverageReference);
+    }
+
+    /**
+     * Records a new data point for a moving average stat
+     *
+     * @param value The new data point to be added
+     * @param mutex The mutex to use for the update
+     * @param movingAverageReference The atomic reference to be updated
+     */
+    protected void updateMovingAverage(long value, Object mutex, AtomicReference<MovingAverage> movingAverageReference) {
+        synchronized (mutex) {
+            movingAverageReference.get().record(value);
+        }
+    }
+
+    /**
+     * Updates the window size for data collection. This also resets any data collected so far.
+     *
+     * @param updatedSize The updated size
+     */
+    void updateMovingAverageWindowSize(int updatedSize) {
+        updateMovingAverageWindowSize(updatedSize, uploadBytesMutex, uploadBytesMovingAverageReference);
+        updateMovingAverageWindowSize(updatedSize, uploadBytesPerSecMutex, uploadBytesPerSecMovingAverageReference);
+        updateMovingAverageWindowSize(updatedSize, uploadTimeMsMutex, uploadTimeMsMovingAverageReference);
+    }
+
+    /**
+     * Updates the window size for data collection. This also resets any data collected so far.
+     *
+     * @param updatedSize The updated size
+     * @param mutex The mutex to use for the update
+     * @param movingAverageReference The atomic reference to be updated
+     */
+    protected void updateMovingAverageWindowSize(int updatedSize, Object mutex, AtomicReference<MovingAverage> movingAverageReference) {
+        synchronized (mutex) {
+            movingAverageReference.set(movingAverageReference.get().copyWithSize(updatedSize));
+        }
+    }
+
+    /**
+     * Validates that the sum of successful operations, failed operations, and the number of operations to add (irrespective of failed/successful) does not exceed the number of operations originally started
+     * @param startedCount Number of operations started
+     * @param failedCount Number of operations failed
+     * @param succeededCount Number of operations successful
+     * @param countToAdd Number of operations to add
+     */
+    private void checkTotal(long startedCount, long failedCount, long succeededCount, long countToAdd) {
+        long delta = startedCount - (failedCount + succeededCount + countToAdd);
+        assert delta >= 0 : "Sum of failure count ("
+            + failedCount
+            + "), success count ("
+            + succeededCount
+            + "), and count to add ("
+            + countToAdd
+            + ") cannot exceed started count ("
+            + startedCount
+            + ")";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteTranslogTransferTracker.java b/server/src/main/java/org/opensearch/index/remote/RemoteTranslogTransferTracker.java
new file mode 100644
index 0000000000000..1a9896540212e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteTranslogTransferTracker.java
@@ -0,0 +1,488 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.common.util.MovingAverage;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.io.IOException;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Stores Remote Translog Store-related stats for a given IndexShard.
+ *
+ * @opensearch.internal
+ */
+public class RemoteTranslogTransferTracker extends RemoteTransferTracker {
+    /**
+     * Epoch timestamp of the last successful Remote Translog Store upload.
+     */
+    private final AtomicLong lastSuccessfulUploadTimestamp;
+
+    /**
+     * Epoch timestamp of the last successful Remote Translog Store download.
+     */
+    private final AtomicLong lastSuccessfulDownloadTimestamp;
+
+    /**
+     * Total number of Remote Translog Store downloads that have been successful.
+     */
+    private final AtomicLong totalDownloadsSucceeded;
+
+    /**
+     * Total number of byte downloads to Remote Translog Store that have been successful.
+     */
+    private final AtomicLong downloadBytesSucceeded;
+
+    /**
+     * Total time spent on Remote Translog Store downloads.
+     */
+    private final AtomicLong totalDownloadTimeInMillis;
+
+    /**
+     * Provides moving average over the last N total size in bytes of translog files downloaded as part of Remote Translog Store download.
+     * N is window size. Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    private final AtomicReference<MovingAverage> downloadBytesMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    private final Object downloadBytesMutex;
+
+    /**
+     * Provides moving average over the last N download speed (in bytes/s) of translog files downloaded as part of Remote Translog Store download.
+     * N is window size. Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    private final AtomicReference<MovingAverage> downloadBytesPerSecMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    private final Object downloadBytesPerSecMutex;
+
+    /**
+     * Provides moving average over the last N overall download time (in nanos) as part of Remote Translog Store download. N is window size.
+     * Wrapped with {@code AtomicReference} for dynamic changes in window size.
+     */
+    private final AtomicReference<MovingAverage> downloadTimeMsMovingAverageReference;
+
+    /**
+     * This lock object is used for making sure we do not miss any data.
+     */
+    private final Object downloadTimeMsMutex;
+
+    public RemoteTranslogTransferTracker(ShardId shardId, int movingAverageWindowSize) {
+        super(shardId, movingAverageWindowSize);
+
+        lastSuccessfulUploadTimestamp = new AtomicLong(0);
+        lastSuccessfulDownloadTimestamp = new AtomicLong(0);
+        totalDownloadsSucceeded = new AtomicLong(0);
+        downloadBytesSucceeded = new AtomicLong(0);
+        totalDownloadTimeInMillis = new AtomicLong(0);
+        downloadBytesMutex = new Object();
+        downloadBytesMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+        downloadBytesPerSecMutex = new Object();
+        downloadBytesPerSecMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+        downloadTimeMsMutex = new Object();
+        downloadTimeMsMovingAverageReference = new AtomicReference<>(new MovingAverage(movingAverageWindowSize));
+    }
+
+    public long getLastSuccessfulUploadTimestamp() {
+        return lastSuccessfulUploadTimestamp.get();
+    }
+
+    public void setLastSuccessfulUploadTimestamp(long lastSuccessfulUploadTimestamp) {
+        this.lastSuccessfulUploadTimestamp.set(lastSuccessfulUploadTimestamp);
+    }
+
+    /**
+     * Updates the window size for data collection. This also resets any data collected so far.
+     *
+     * @param updatedSize the updated size
+     */
+    void updateMovingAverageWindowSize(int updatedSize) {
+        super.updateMovingAverageWindowSize(updatedSize);
+        updateMovingAverageWindowSize(updatedSize, downloadBytesMutex, downloadBytesMovingAverageReference);
+        updateMovingAverageWindowSize(updatedSize, downloadBytesPerSecMutex, downloadBytesPerSecMovingAverageReference);
+        updateMovingAverageWindowSize(updatedSize, downloadTimeMsMutex, downloadTimeMsMovingAverageReference);
+    }
+
+    public long getTotalDownloadsSucceeded() {
+        return totalDownloadsSucceeded.get();
+    }
+
+    void incrementDownloadsSucceeded() {
+        totalDownloadsSucceeded.addAndGet(1);
+    }
+
+    public long getDownloadBytesSucceeded() {
+        return downloadBytesSucceeded.get();
+    }
+
+    public void addDownloadBytesSucceeded(long count) {
+        downloadBytesSucceeded.addAndGet(count);
+    }
+
+    public long getTotalDownloadTimeInMillis() {
+        return totalDownloadTimeInMillis.get();
+    }
+
+    public void addDownloadTimeInMillis(long duration) {
+        totalDownloadTimeInMillis.addAndGet(duration);
+    }
+
+    public long getLastSuccessfulDownloadTimestamp() {
+        return lastSuccessfulDownloadTimestamp.get();
+    }
+
+    void setLastSuccessfulDownloadTimestamp(long lastSuccessfulDownloadTimestamp) {
+        this.lastSuccessfulDownloadTimestamp.set(lastSuccessfulDownloadTimestamp);
+    }
+
+    boolean isDownloadBytesMovingAverageReady() {
+        return downloadBytesMovingAverageReference.get().isReady();
+    }
+
+    double getDownloadBytesMovingAverage() {
+        return downloadBytesMovingAverageReference.get().getAverage();
+    }
+
+    void updateDownloadBytesMovingAverage(long count) {
+        updateMovingAverage(count, downloadBytesMutex, downloadBytesMovingAverageReference);
+    }
+
+    boolean isDownloadBytesPerSecMovingAverageReady() {
+        return downloadBytesPerSecMovingAverageReference.get().isReady();
+    }
+
+    double getDownloadBytesPerSecMovingAverage() {
+        return downloadBytesPerSecMovingAverageReference.get().getAverage();
+    }
+
+    void updateDownloadBytesPerSecMovingAverage(long speed) {
+        updateMovingAverage(speed, downloadBytesPerSecMutex, downloadBytesPerSecMovingAverageReference);
+    }
+
+    boolean isDownloadTimeMovingAverageReady() {
+        return downloadTimeMsMovingAverageReference.get().isReady();
+    }
+
+    double getDownloadTimeMovingAverage() {
+        return downloadTimeMsMovingAverageReference.get().getAverage();
+    }
+
+    void updateDownloadTimeMovingAverage(long duration) {
+        updateMovingAverage(duration, downloadTimeMsMutex, downloadTimeMsMovingAverageReference);
+    }
+
+    /**
+     * Record stats related to a download from Remote Translog Store
+     * @param prevDownloadBytesSucceeded Number of downloadBytesSucceeded in this tracker before the download was started
+     * @param prevDownloadTimeInMillis Amount of downloadTimeInMillis in this tracker before the download was started
+     */
+    public void recordDownloadStats(long prevDownloadBytesSucceeded, long prevDownloadTimeInMillis) {
+        setLastSuccessfulDownloadTimestamp(System.currentTimeMillis());
+        incrementDownloadsSucceeded();
+        long bytesDownloaded = getDownloadBytesSucceeded() - prevDownloadBytesSucceeded;
+        updateDownloadBytesMovingAverage(bytesDownloaded);
+        long durationInMillis = getTotalDownloadTimeInMillis() - prevDownloadTimeInMillis;
+        updateDownloadTimeMovingAverage(durationInMillis);
+        if (durationInMillis > 0) {
+            updateDownloadBytesPerSecMovingAverage(bytesDownloaded * 1_000L / durationInMillis);
+        }
+    }
+
+    /**
+     * Gets the tracker's state as seen in the stats API
+     * @return Stats object with the tracker's stats
+     */
+    public RemoteTranslogTransferTracker.Stats stats() {
+        return new RemoteTranslogTransferTracker.Stats(
+            shardId,
+            lastSuccessfulUploadTimestamp.get(),
+            totalUploadsStarted.get(),
+            totalUploadsSucceeded.get(),
+            totalUploadsFailed.get(),
+            uploadBytesStarted.get(),
+            uploadBytesSucceeded.get(),
+            uploadBytesFailed.get(),
+            totalUploadTimeInMillis.get(),
+            uploadBytesMovingAverageReference.get().getAverage(),
+            uploadBytesPerSecMovingAverageReference.get().getAverage(),
+            uploadTimeMsMovingAverageReference.get().getAverage(),
+            lastSuccessfulDownloadTimestamp.get(),
+            totalDownloadsSucceeded.get(),
+            downloadBytesSucceeded.get(),
+            totalDownloadTimeInMillis.get(),
+            downloadBytesMovingAverageReference.get().getAverage(),
+            downloadBytesPerSecMovingAverageReference.get().getAverage(),
+            downloadTimeMsMovingAverageReference.get().getAverage()
+        );
+    }
+
+    /**
+     * Represents the tracker's state as seen in the stats API.
+     *
+     * @opensearch.internal
+     */
+    public static class Stats implements Writeable {
+
+        final ShardId shardId;
+
+        /**
+         * Epoch timestamp of the last successful Remote Translog Store upload.
+         */
+        public final long lastSuccessfulUploadTimestamp;
+
+        /**
+         * Total number of Remote Translog Store uploads that have been started.
+         */
+        public final long totalUploadsStarted;
+
+        /**
+         * Total number of Remote Translog Store uploads that have failed.
+         */
+        public final long totalUploadsFailed;
+
+        /**
+         * Total number of Remote Translog Store that have been successful.
+         */
+        public final long totalUploadsSucceeded;
+
+        /**
+         * Total number of byte uploads to Remote Translog Store that have been started.
+         */
+        public final long uploadBytesStarted;
+
+        /**
+         * Total number of byte uploads to Remote Translog Store that have failed.
+         */
+        public final long uploadBytesFailed;
+
+        /**
+         * Total number of byte uploads to Remote Translog Store that have been successful.
+         */
+        public final long uploadBytesSucceeded;
+
+        /**
+         * Total time spent on Remote Translog Store uploads.
+         */
+        public final long totalUploadTimeInMillis;
+
+        /**
+         * Size of a Remote Translog Store upload in bytes.
+         */
+        public final double uploadBytesMovingAverage;
+
+        /**
+         * Speed of a Remote Translog Store upload in bytes-per-second.
+         */
+        public final double uploadBytesPerSecMovingAverage;
+
+        /**
+         *  Time taken by a Remote Translog Store upload.
+         */
+        public final double uploadTimeMovingAverage;
+
+        /**
+         * Epoch timestamp of the last successful Remote Translog Store download.
+         */
+        public final long lastSuccessfulDownloadTimestamp;
+
+        /**
+         * Total number of Remote Translog Store downloads that have been successful.
+         */
+        public final long totalDownloadsSucceeded;
+
+        /**
+         * Total number of byte downloads from Remote Translog Store that have been successful.
+         */
+        public final long downloadBytesSucceeded;
+
+        /**
+         * Total time spent on Remote Translog Store downloads.
+         */
+        public final long totalDownloadTimeInMillis;
+
+        /**
+         * Size of a Remote Translog Store download in bytes.
+         */
+        public final double downloadBytesMovingAverage;
+
+        /**
+         * Speed of a Remote Translog Store download in bytes-per-second.
+         */
+        public final double downloadBytesPerSecMovingAverage;
+
+        /**
+         *  Time taken by a Remote Translog Store download.
+         */
+        public final double downloadTimeMovingAverage;
+
+        public Stats(
+            ShardId shardId,
+            long lastSuccessfulUploadTimestamp,
+            long totalUploadsStarted,
+            long totalUploadsSucceeded,
+            long totalUploadsFailed,
+            long uploadBytesStarted,
+            long uploadBytesSucceeded,
+            long uploadBytesFailed,
+            long totalUploadTimeInMillis,
+            double uploadBytesMovingAverage,
+            double uploadBytesPerSecMovingAverage,
+            double uploadTimeMovingAverage,
+            long lastSuccessfulDownloadTimestamp,
+            long totalDownloadsSucceeded,
+            long downloadBytesSucceeded,
+            long totalDownloadTimeInMillis,
+            double downloadBytesMovingAverage,
+            double downloadBytesPerSecMovingAverage,
+            double downloadTimeMovingAverage
+        ) {
+            this.shardId = shardId;
+
+            this.lastSuccessfulUploadTimestamp = lastSuccessfulUploadTimestamp;
+            this.totalUploadsStarted = totalUploadsStarted;
+            this.totalUploadsFailed = totalUploadsFailed;
+            this.totalUploadsSucceeded = totalUploadsSucceeded;
+            this.uploadBytesStarted = uploadBytesStarted;
+            this.uploadBytesFailed = uploadBytesFailed;
+            this.uploadBytesSucceeded = uploadBytesSucceeded;
+            this.totalUploadTimeInMillis = totalUploadTimeInMillis;
+            this.uploadBytesMovingAverage = uploadBytesMovingAverage;
+            this.uploadBytesPerSecMovingAverage = uploadBytesPerSecMovingAverage;
+            this.uploadTimeMovingAverage = uploadTimeMovingAverage;
+
+            this.lastSuccessfulDownloadTimestamp = lastSuccessfulDownloadTimestamp;
+            this.totalDownloadsSucceeded = totalDownloadsSucceeded;
+            this.downloadBytesSucceeded = downloadBytesSucceeded;
+            this.totalDownloadTimeInMillis = totalDownloadTimeInMillis;
+            this.downloadBytesMovingAverage = downloadBytesMovingAverage;
+            this.downloadBytesPerSecMovingAverage = downloadBytesPerSecMovingAverage;
+            this.downloadTimeMovingAverage = downloadTimeMovingAverage;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            this.shardId = new ShardId(in);
+
+            this.lastSuccessfulUploadTimestamp = in.readVLong();
+            this.totalUploadsStarted = in.readVLong();
+            this.totalUploadsFailed = in.readVLong();
+            this.totalUploadsSucceeded = in.readVLong();
+            this.uploadBytesStarted = in.readVLong();
+            this.uploadBytesFailed = in.readVLong();
+            this.uploadBytesSucceeded = in.readVLong();
+            this.totalUploadTimeInMillis = in.readVLong();
+            this.uploadBytesMovingAverage = in.readDouble();
+            this.uploadBytesPerSecMovingAverage = in.readDouble();
+            this.uploadTimeMovingAverage = in.readDouble();
+
+            this.lastSuccessfulDownloadTimestamp = in.readVLong();
+            this.totalDownloadsSucceeded = in.readVLong();
+            this.downloadBytesSucceeded = in.readVLong();
+            this.totalDownloadTimeInMillis = in.readVLong();
+            this.downloadBytesMovingAverage = in.readDouble();
+            this.downloadBytesPerSecMovingAverage = in.readDouble();
+            this.downloadTimeMovingAverage = in.readDouble();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            shardId.writeTo(out);
+
+            out.writeVLong(lastSuccessfulUploadTimestamp);
+            out.writeVLong(totalUploadsStarted);
+            out.writeVLong(totalUploadsFailed);
+            out.writeVLong(totalUploadsSucceeded);
+            out.writeVLong(uploadBytesStarted);
+            out.writeVLong(uploadBytesFailed);
+            out.writeVLong(uploadBytesSucceeded);
+            out.writeVLong(totalUploadTimeInMillis);
+            out.writeDouble(uploadBytesMovingAverage);
+            out.writeDouble(uploadBytesPerSecMovingAverage);
+            out.writeDouble(uploadTimeMovingAverage);
+
+            out.writeVLong(lastSuccessfulDownloadTimestamp);
+            out.writeVLong(totalDownloadsSucceeded);
+            out.writeVLong(downloadBytesSucceeded);
+            out.writeVLong(totalDownloadTimeInMillis);
+            out.writeDouble(downloadBytesMovingAverage);
+            out.writeDouble(downloadBytesPerSecMovingAverage);
+            out.writeDouble(downloadTimeMovingAverage);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            RemoteTranslogTransferTracker.Stats other = (RemoteTranslogTransferTracker.Stats) obj;
+
+            return this.shardId.equals(other.shardId)
+                && this.lastSuccessfulUploadTimestamp == other.lastSuccessfulUploadTimestamp
+                && this.totalUploadsStarted == other.totalUploadsStarted
+                && this.totalUploadsFailed == other.totalUploadsFailed
+                && this.totalUploadsSucceeded == other.totalUploadsSucceeded
+                && this.uploadBytesStarted == other.uploadBytesStarted
+                && this.uploadBytesFailed == other.uploadBytesFailed
+                && this.uploadBytesSucceeded == other.uploadBytesSucceeded
+                && this.totalUploadTimeInMillis == other.totalUploadTimeInMillis
+                && Double.compare(this.uploadBytesMovingAverage, other.uploadBytesMovingAverage) == 0
+                && Double.compare(this.uploadBytesPerSecMovingAverage, other.uploadBytesPerSecMovingAverage) == 0
+                && Double.compare(this.uploadTimeMovingAverage, other.uploadTimeMovingAverage) == 0
+                && this.lastSuccessfulDownloadTimestamp == other.lastSuccessfulDownloadTimestamp
+                && this.totalDownloadsSucceeded == other.totalDownloadsSucceeded
+                && this.downloadBytesSucceeded == other.downloadBytesSucceeded
+                && this.totalDownloadTimeInMillis == other.totalDownloadTimeInMillis
+                && Double.compare(this.downloadBytesMovingAverage, other.downloadBytesMovingAverage) == 0
+                && Double.compare(this.downloadBytesPerSecMovingAverage, other.downloadBytesPerSecMovingAverage) == 0
+                && Double.compare(this.downloadTimeMovingAverage, other.downloadTimeMovingAverage) == 0;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(
+                shardId.toString(),
+                lastSuccessfulUploadTimestamp,
+                totalUploadsStarted,
+                totalUploadsFailed,
+                totalUploadsSucceeded,
+                uploadBytesStarted,
+                uploadBytesFailed,
+                uploadBytesSucceeded,
+                totalUploadTimeInMillis,
+                uploadBytesMovingAverage,
+                uploadBytesPerSecMovingAverage,
+                uploadTimeMovingAverage,
+                lastSuccessfulDownloadTimestamp,
+                totalDownloadsSucceeded,
+                downloadBytesSucceeded,
+                totalDownloadTimeInMillis,
+                downloadBytesMovingAverage,
+                downloadBytesPerSecMovingAverage,
+                downloadTimeMovingAverage
+            );
+        }
+    }
+
+    /**
+     * Validates if the stats in this tracker and the stats contained in the given stats object are same or not
+     * @param other Stats object to compare this tracker against
+     * @return true if stats are same and false otherwise
+     */
+    boolean hasSameStatsAs(RemoteTranslogTransferTracker.Stats other) {
+        return this.stats().equals(other);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/remote/package-info.java b/server/src/main/java/org/opensearch/index/remote/package-info.java
new file mode 100644
index 0000000000000..a3aa969316372
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/remote/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes related to remote segments and translogs */
+package org.opensearch.index.remote;
diff --git a/server/src/main/java/org/opensearch/index/search/MatchQuery.java b/server/src/main/java/org/opensearch/index/search/MatchQuery.java
index 485715c430b3f..ade4fb1e69586 100644
--- a/server/src/main/java/org/opensearch/index/search/MatchQuery.java
+++ b/server/src/main/java/org/opensearch/index/search/MatchQuery.java
@@ -58,13 +58,13 @@
 import org.apache.lucene.util.QueryBuilder;
 import org.apache.lucene.util.graph.GraphTokenStreamFiniteStrings;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.lucene.search.SpanBooleanQueryRewriteWithMaxClause;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.TextFieldMapper;
@@ -82,8 +82,18 @@
 import static org.opensearch.common.lucene.search.Queries.newLenientFieldQuery;
 import static org.opensearch.common.lucene.search.Queries.newUnmappedFieldQuery;
 
+/**
+ * Foundation match query
+ *
+ * @opensearch.internal
+ */
 public class MatchQuery {
 
+    /**
+     * Type of the match
+     *
+     * @opensearch.internal
+     */
     public enum Type implements Writeable {
         /**
          * The text is analyzed and terms are added to a boolean query.
@@ -124,6 +134,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Query with zero terms
+     *
+     * @opensearch.internal
+     */
     public enum ZeroTermsQuery implements Writeable {
         NONE(0),
         ALL(1),
@@ -652,9 +667,9 @@ private void add(BooleanQuery.Builder q, String field, List<Term> current, Boole
             } else {
                 // We don't apply prefix on synonyms
                 final TermAndBoost[] termAndBoosts = current.stream()
-                    .map(t -> new TermAndBoost(t, BoostAttribute.DEFAULT_BOOST))
+                    .map(t -> new TermAndBoost(t.bytes(), BoostAttribute.DEFAULT_BOOST))
                     .toArray(TermAndBoost[]::new);
-                q.add(newSynonymQuery(termAndBoosts), operator);
+                q.add(newSynonymQuery(field, termAndBoosts), operator);
             }
         }
 
@@ -738,6 +753,14 @@ private Query analyzeGraphBoolean(String field, TokenStream source, BooleanClaus
                 lastState = end;
                 final Query queryPos;
                 boolean usePrefix = isPrefix && end == -1;
+                /**
+                 * check if the GraphTokenStreamFiniteStrings graph is empty
+                 * return empty BooleanQuery result
+                 */
+                Iterator<TokenStream> graphIt = graph.getFiniteStrings();
+                if (!graphIt.hasNext()) {
+                    return builder.build();
+                }
                 if (graph.hasSidePath(start)) {
                     final Iterator<TokenStream> it = graph.getFiniteStrings(start, end);
                     Iterator<Query> queries = new Iterator<Query>() {
@@ -767,9 +790,9 @@ public Query next() {
                     } else {
                         // We don't apply prefix on synonyms
                         final TermAndBoost[] termAndBoosts = Arrays.stream(terms)
-                            .map(t -> new TermAndBoost(t, BoostAttribute.DEFAULT_BOOST))
+                            .map(t -> new TermAndBoost(t.bytes(), BoostAttribute.DEFAULT_BOOST))
                             .toArray(TermAndBoost[]::new);
-                        queryPos = newSynonymQuery(termAndBoosts);
+                        queryPos = newSynonymQuery(field, termAndBoosts);
                     }
                 }
                 if (queryPos != null) {
diff --git a/server/src/main/java/org/opensearch/index/search/MultiMatchQuery.java b/server/src/main/java/org/opensearch/index/search/MultiMatchQuery.java
index f924c698c0f22..241f05af2c512 100644
--- a/server/src/main/java/org/opensearch/index/search/MultiMatchQuery.java
+++ b/server/src/main/java/org/opensearch/index/search/MultiMatchQuery.java
@@ -58,6 +58,11 @@
 
 import static org.opensearch.common.lucene.search.Queries.newLenientFieldQuery;
 
+/**
+ * Foundation multi match query
+ *
+ * @opensearch.internal
+ */
 public class MultiMatchQuery extends MatchQuery {
 
     private Float groupTieBreaker = null;
@@ -213,10 +218,10 @@ private class BlendedQueryBuilder extends MatchQueryBuilder {
         }
 
         @Override
-        protected Query newSynonymQuery(TermAndBoost[] terms) {
+        protected Query newSynonymQuery(String field, TermAndBoost[] terms) {
             BytesRef[] values = new BytesRef[terms.length];
             for (int i = 0; i < terms.length; i++) {
-                values[i] = terms[i].term.bytes();
+                values[i] = terms[i].term;
             }
             return blendTerms(context, values, commonTermsCutoff, tieBreaker, lenient, blendedFields);
         }
@@ -340,6 +345,11 @@ static Query blendTerms(
         }
     }
 
+    /**
+     * Holder for a field and it's boost value
+     *
+     * @opensearch.internal
+     */
     static final class FieldAndBoost {
         final MappedFieldType fieldType;
         final float boost;
diff --git a/server/src/main/java/org/opensearch/index/search/NestedHelper.java b/server/src/main/java/org/opensearch/index/search/NestedHelper.java
index 487dc2bddde6b..50e7e41b95be7 100644
--- a/server/src/main/java/org/opensearch/index/search/NestedHelper.java
+++ b/server/src/main/java/org/opensearch/index/search/NestedHelper.java
@@ -34,6 +34,7 @@
 
 import org.apache.lucene.index.PrefixCodedTerms;
 import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
@@ -44,12 +45,14 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.search.BooleanClause.Occur;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ObjectMapper;
 
 /** Utility class to filter parent and children clauses when building nested
- * queries. */
+ * queries.
+ *
+ * @opensearch.internal
+ */
 public final class NestedHelper {
 
     private final MapperService mapperService;
diff --git a/server/src/main/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQuery.java b/server/src/main/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQuery.java
index 66f66be43b0ca..cd28d8b6ef04e 100644
--- a/server/src/main/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQuery.java
+++ b/server/src/main/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQuery.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.search;
 
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
@@ -45,7 +44,11 @@
 import java.io.IOException;
 import java.util.Objects;
 
-/** A {@link ToParentBlockJoinQuery} that allows to retrieve its nested path. */
+/**
+ * A {@link ToParentBlockJoinQuery} that allows to retrieve its nested path.
+ *
+ * @opensearch.internal
+ */
 public final class OpenSearchToParentBlockJoinQuery extends Query {
 
     private final ToParentBlockJoinQuery query;
@@ -78,8 +81,8 @@ public ScoreMode getScoreMode() {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
-        Query innerRewrite = query.rewrite(reader);
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        Query innerRewrite = query.rewrite(searcher);
         if (innerRewrite != query) {
             // Right now ToParentBlockJoinQuery always rewrites to a ToParentBlockJoinQuery
             // so the else block will never be used. It is useful in the case that
@@ -93,7 +96,7 @@ public Query rewrite(IndexReader reader) throws IOException {
                 return innerRewrite;
             }
         }
-        return super.rewrite(reader);
+        return super.rewrite(searcher);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/search/QueryParserHelper.java b/server/src/main/java/org/opensearch/index/search/QueryParserHelper.java
index 68c61bd9acc54..5e9839385ce20 100644
--- a/server/src/main/java/org/opensearch/index/search/QueryParserHelper.java
+++ b/server/src/main/java/org/opensearch/index/search/QueryParserHelper.java
@@ -48,6 +48,8 @@
 
 /**
  * Helpers to extract and expand field names and boosts
+ *
+ * @opensearch.internal
  */
 public final class QueryParserHelper {
     private QueryParserHelper() {}
diff --git a/server/src/main/java/org/opensearch/index/search/QueryStringQueryParser.java b/server/src/main/java/org/opensearch/index/search/QueryStringQueryParser.java
index e9437f5704851..7d6cbc0064535 100644
--- a/server/src/main/java/org/opensearch/index/search/QueryStringQueryParser.java
+++ b/server/src/main/java/org/opensearch/index/search/QueryStringQueryParser.java
@@ -56,11 +56,10 @@
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.WildcardQuery;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DateFieldMapper.DateFieldType;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
@@ -70,7 +69,6 @@
 import org.opensearch.index.query.ExistsQueryBuilder;
 import org.opensearch.index.query.MultiMatchQueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.query.support.QueryParsers;
 
 import java.io.IOException;
 import java.time.ZoneId;
@@ -91,6 +89,8 @@
  * queries based on the mapping information.
  * This class uses {@link MultiMatchQuery} to build the text query around operators and {@link XQueryParser}
  * to assemble the result logically.
+ *
+ * @opensearch.internal
  */
 public class QueryStringQueryParser extends XQueryParser {
     private static final String EXISTS_FIELD = "_exists_";
@@ -110,7 +110,7 @@ public class QueryStringQueryParser extends XQueryParser {
     private ZoneId timeZone;
     private Fuzziness fuzziness = Fuzziness.AUTO;
     private int fuzzyMaxExpansions = FuzzyQuery.defaultMaxExpansions;
-    private MultiTermQuery.RewriteMethod fuzzyRewriteMethod;
+    private MultiTermQuery.RewriteMethod fuzzyRewriteMethod = MultiTermQuery.CONSTANT_SCORE_REWRITE;
     private boolean fuzzyTranspositions = FuzzyQuery.defaultTranspositions;
 
     /**
@@ -527,9 +527,11 @@ private Query getFuzzyQuerySingle(String field, String termStr, float minSimilar
     @Override
     protected Query newFuzzyQuery(Term term, float minimumSimilarity, int prefixLength) {
         int numEdits = Fuzziness.build(minimumSimilarity).asDistance(term.text());
-        FuzzyQuery query = new FuzzyQuery(term, numEdits, prefixLength, fuzzyMaxExpansions, fuzzyTranspositions);
-        QueryParsers.setRewriteMethod(query, fuzzyRewriteMethod);
-        return query;
+        if (fuzzyRewriteMethod != null) {
+            return new FuzzyQuery(term, numEdits, prefixLength, fuzzyMaxExpansions, fuzzyTranspositions, fuzzyRewriteMethod);
+        } else {
+            return new FuzzyQuery(term, numEdits, prefixLength, fuzzyMaxExpansions, fuzzyTranspositions);
+        }
     }
 
     @Override
@@ -562,7 +564,7 @@ private Query getPrefixQuerySingle(String field, String termStr) throws ParseExc
             if (currentFieldType == null || currentFieldType.getTextSearchInfo() == TextSearchInfo.NONE) {
                 return newUnmappedFieldQuery(field);
             }
-            setAnalyzer(forceAnalyzer == null ? queryBuilder.context.getSearchAnalyzer(currentFieldType) : forceAnalyzer);
+            setAnalyzer(getSearchAnalyzer(currentFieldType));
             Query query = null;
             if (currentFieldType.getTextSearchInfo().isTokenized() == false) {
                 query = currentFieldType.prefixQuery(termStr, getMultiTermRewriteMethod(), context);
@@ -727,7 +729,8 @@ private Query getWildcardQuerySingle(String field, String termStr) throws ParseE
             if (getAllowLeadingWildcard() == false && (termStr.startsWith("*") || termStr.startsWith("?"))) {
                 throw new ParseException("'*' or '?' not allowed as first character in WildcardQuery");
             }
-            return currentFieldType.wildcardQuery(termStr, getMultiTermRewriteMethod(), context);
+            // query string query is always normalized
+            return currentFieldType.normalizedWildcardQuery(termStr, getMultiTermRewriteMethod(), context);
         } catch (RuntimeException e) {
             if (lenient) {
                 return newLenientFieldQuery(field, e);
@@ -738,6 +741,13 @@ private Query getWildcardQuerySingle(String field, String termStr) throws ParseE
         }
     }
 
+    private Analyzer getSearchAnalyzer(MappedFieldType currentFieldType) {
+        if (forceAnalyzer == null) {
+            return queryBuilder.context.getSearchAnalyzer(currentFieldType);
+        }
+        return forceAnalyzer;
+    }
+
     @Override
     protected Query getRegexpQuery(String field, String termStr) throws ParseException {
         final int maxAllowedRegexLength = context.getIndexSettings().getMaxRegexLength();
@@ -778,11 +788,8 @@ private Query getRegexpQuerySingle(String field, String termStr) throws ParseExc
             if (currentFieldType == null) {
                 return newUnmappedFieldQuery(field);
             }
-            if (forceAnalyzer != null) {
-                setAnalyzer(forceAnalyzer);
-                return super.getRegexpQuery(field, termStr);
-            }
-            return currentFieldType.regexpQuery(termStr, RegExp.ALL, 0, getDeterminizeWorkLimit(), getMultiTermRewriteMethod(), context);
+            setAnalyzer(getSearchAnalyzer(currentFieldType));
+            return super.getRegexpQuery(field, termStr);
         } catch (RuntimeException e) {
             if (lenient) {
                 return newLenientFieldQuery(field, e);
diff --git a/server/src/main/java/org/opensearch/index/search/SimpleQueryStringQueryParser.java b/server/src/main/java/org/opensearch/index/search/SimpleQueryStringQueryParser.java
index f4f68634d0df5..ce43aaf14c982 100644
--- a/server/src/main/java/org/opensearch/index/search/SimpleQueryStringQueryParser.java
+++ b/server/src/main/java/org/opensearch/index/search/SimpleQueryStringQueryParser.java
@@ -66,6 +66,8 @@
 /**
  * Wrapper class for Lucene's SimpleQueryStringQueryParser that allows us to redefine
  * different types of queries.
+ *
+ * @opensearch.internal
  */
 public class SimpleQueryStringQueryParser extends SimpleQueryParser {
 
@@ -308,6 +310,8 @@ private Query newPossiblyAnalyzedQuery(String field, String termStr, Analyzer an
     /**
      * Class encapsulating the settings for the SimpleQueryString query, with
      * their default values
+     *
+     * @opensearch.internal
      */
     public static class Settings {
         /** Specifies whether lenient query parsing should be used. */
diff --git a/server/src/main/java/org/opensearch/index/search/comparators/UnsignedLongComparator.java b/server/src/main/java/org/opensearch/index/search/comparators/UnsignedLongComparator.java
new file mode 100644
index 0000000000000..78b4a5f04c955
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/search/comparators/UnsignedLongComparator.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.search.comparators;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
+import org.apache.lucene.search.LeafFieldComparator;
+import org.apache.lucene.search.comparators.NumericComparator;
+import org.opensearch.common.Numbers;
+
+import java.io.IOException;
+import java.math.BigInteger;
+
+/** The comparator for unsigned long numeric type */
+public class UnsignedLongComparator extends NumericComparator<BigInteger> {
+    private final BigInteger[] values;
+    protected BigInteger topValue;
+    protected BigInteger bottom;
+
+    public UnsignedLongComparator(int numHits, String field, BigInteger missingValue, boolean reverse, boolean enableSkipping) {
+        super(field, missingValue != null ? missingValue : Numbers.MIN_UNSIGNED_LONG_VALUE, reverse, enableSkipping, BigIntegerPoint.BYTES);
+        values = new BigInteger[numHits];
+    }
+
+    @Override
+    public int compare(int slot1, int slot2) {
+        return values[slot1].compareTo(values[slot2]);
+    }
+
+    @Override
+    public void setTopValue(BigInteger value) {
+        super.setTopValue(value);
+        topValue = value;
+    }
+
+    @Override
+    public BigInteger value(int slot) {
+        return values[slot];
+    }
+
+    @Override
+    public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
+        return new UnsignedLongLeafComparator(context);
+    }
+
+    /** Leaf comparator for {@link UnsignedLongComparator} that provides skipping functionality */
+    public class UnsignedLongLeafComparator extends NumericLeafComparator {
+
+        public UnsignedLongLeafComparator(LeafReaderContext context) throws IOException {
+            super(context);
+        }
+
+        private BigInteger getValueForDoc(int doc) throws IOException {
+            if (docValues.advanceExact(doc)) {
+                return Numbers.toUnsignedBigInteger(docValues.longValue());
+            } else {
+                return missingValue;
+            }
+        }
+
+        @Override
+        public void setBottom(int slot) throws IOException {
+            bottom = values[slot];
+            super.setBottom(slot);
+        }
+
+        @Override
+        public int compareBottom(int doc) throws IOException {
+            return bottom.compareTo(getValueForDoc(doc));
+        }
+
+        @Override
+        public int compareTop(int doc) throws IOException {
+            return topValue.compareTo(getValueForDoc(doc));
+        }
+
+        @Override
+        public void copy(int slot, int doc) throws IOException {
+            values[slot] = getValueForDoc(doc);
+            super.copy(slot, doc);
+        }
+
+        @Override
+        protected boolean isMissingValueCompetitive() {
+            int result = missingValue.compareTo(bottom);
+            // in reverse (desc) sort missingValue is competitive when it's greater or equal to bottom,
+            // in asc sort missingValue is competitive when it's smaller or equal to bottom
+            return reverse ? (result >= 0) : (result <= 0);
+        }
+
+        @Override
+        protected void encodeBottom(byte[] packedValue) {
+            BigIntegerPoint.encodeDimension(bottom, packedValue, 0);
+        }
+
+        @Override
+        protected void encodeTop(byte[] packedValue) {
+            BigIntegerPoint.encodeDimension(topValue, packedValue, 0);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/search/comparators/package-info.java b/server/src/main/java/org/opensearch/index/search/comparators/package-info.java
new file mode 100644
index 0000000000000..000dc9f71132b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/search/comparators/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Additional comparators for numeric types */
+package org.opensearch.index.search.comparators;
diff --git a/server/src/main/java/org/opensearch/index/search/package-info.java b/server/src/main/java/org/opensearch/index/search/package-info.java
new file mode 100644
index 0000000000000..a421f5372264f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/search/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Utility classes for building OpenSearch queries */
+package org.opensearch.index.search;
diff --git a/server/src/main/java/org/opensearch/index/search/stats/SearchStats.java b/server/src/main/java/org/opensearch/index/search/stats/SearchStats.java
index d55c2924eccf6..1f9144b28f286 100644
--- a/server/src/main/java/org/opensearch/index/search/stats/SearchStats.java
+++ b/server/src/main/java/org/opensearch/index/search/stats/SearchStats.java
@@ -32,29 +32,118 @@
 
 package org.opensearch.index.search.stats;
 
+import org.opensearch.Version;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchRequestStats;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Encapsulates stats for search time
+ *
+ * @opensearch.internal
+ */
 public class SearchStats implements Writeable, ToXContentFragment {
 
+    /**
+     * Holds statistic values for a particular phase.
+     *
+     * @opensearch.internal
+     */
+    public static class PhaseStatsLongHolder implements Writeable {
+
+        long current;
+        long total;
+        long timeInMillis;
+
+        public long getCurrent() {
+            return current;
+        }
+
+        public long getTotal() {
+            return total;
+        }
+
+        public long getTimeInMillis() {
+            return timeInMillis;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeVLong(current);
+            out.writeVLong(total);
+            out.writeVLong(timeInMillis);
+        }
+
+        PhaseStatsLongHolder() {
+            this(0, 0, 0);
+        }
+
+        PhaseStatsLongHolder(long current, long total, long timeInMillis) {
+            this.current = current;
+            this.total = total;
+            this.timeInMillis = timeInMillis;
+        }
+
+        PhaseStatsLongHolder(StreamInput in) throws IOException {
+            this.current = in.readVLong();
+            this.total = in.readVLong();
+            this.timeInMillis = in.readVLong();
+        }
+
+    }
+
+    /**
+     * Holds requests stats for different phases.
+     *
+     * @opensearch.internal
+     */
+    public static class RequestStatsLongHolder {
+
+        Map<String, PhaseStatsLongHolder> requestStatsHolder = new HashMap<>();
+
+        public Map<String, PhaseStatsLongHolder> getRequestStatsHolder() {
+            return requestStatsHolder;
+        }
+
+        RequestStatsLongHolder() {
+            for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+                requestStatsHolder.put(searchPhaseName.getName(), new PhaseStatsLongHolder());
+            }
+        }
+    }
+
+    /**
+     * Holder of statistics values
+     *
+     * @opensearch.internal
+     */
+
     public static class Stats implements Writeable, ToXContentFragment {
 
         private long queryCount;
         private long queryTimeInMillis;
         private long queryCurrent;
 
+        private long concurrentQueryCount;
+        private long concurrentQueryTimeInMillis;
+        private long concurrentQueryCurrent;
+        private long queryConcurrency;
+
         private long fetchCount;
         private long fetchTimeInMillis;
         private long fetchCurrent;
@@ -67,6 +156,17 @@ public static class Stats implements Writeable, ToXContentFragment {
         private long suggestTimeInMillis;
         private long suggestCurrent;
 
+        private long pitCount;
+        private long pitTimeInMillis;
+        private long pitCurrent;
+
+        @Nullable
+        private RequestStatsLongHolder requestStatsLongHolder;
+
+        public RequestStatsLongHolder getRequestStatsLongHolder() {
+            return requestStatsLongHolder;
+        }
+
         private Stats() {
             // for internal use, initializes all counts to 0
         }
@@ -75,20 +175,33 @@ public Stats(
             long queryCount,
             long queryTimeInMillis,
             long queryCurrent,
+            long concurrentQueryCount,
+            long concurrentQueryTimeInMillis,
+            long concurrentQueryCurrent,
+            long queryConcurrency,
             long fetchCount,
             long fetchTimeInMillis,
             long fetchCurrent,
             long scrollCount,
             long scrollTimeInMillis,
             long scrollCurrent,
+            long pitCount,
+            long pitTimeInMillis,
+            long pitCurrent,
             long suggestCount,
             long suggestTimeInMillis,
             long suggestCurrent
         ) {
+            this.requestStatsLongHolder = new RequestStatsLongHolder();
             this.queryCount = queryCount;
             this.queryTimeInMillis = queryTimeInMillis;
             this.queryCurrent = queryCurrent;
 
+            this.concurrentQueryCount = concurrentQueryCount;
+            this.concurrentQueryTimeInMillis = concurrentQueryTimeInMillis;
+            this.concurrentQueryCurrent = concurrentQueryCurrent;
+            this.queryConcurrency = queryConcurrency;
+
             this.fetchCount = fetchCount;
             this.fetchTimeInMillis = fetchTimeInMillis;
             this.fetchCurrent = fetchCurrent;
@@ -100,6 +213,10 @@ public Stats(
             this.suggestCount = suggestCount;
             this.suggestTimeInMillis = suggestTimeInMillis;
             this.suggestCurrent = suggestCurrent;
+
+            this.pitCount = pitCount;
+            this.pitTimeInMillis = pitTimeInMillis;
+            this.pitCurrent = pitCurrent;
         }
 
         private Stats(StreamInput in) throws IOException {
@@ -118,6 +235,23 @@ private Stats(StreamInput in) throws IOException {
             suggestCount = in.readVLong();
             suggestTimeInMillis = in.readVLong();
             suggestCurrent = in.readVLong();
+
+            if (in.getVersion().onOrAfter(Version.V_2_4_0)) {
+                pitCount = in.readVLong();
+                pitTimeInMillis = in.readVLong();
+                pitCurrent = in.readVLong();
+            }
+
+            if (in.getVersion().onOrAfter(Version.V_2_11_0)) {
+                this.requestStatsLongHolder = new RequestStatsLongHolder();
+                requestStatsLongHolder.requestStatsHolder = in.readMap(StreamInput::readString, PhaseStatsLongHolder::new);
+            }
+            if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+                concurrentQueryCount = in.readVLong();
+                concurrentQueryTimeInMillis = in.readVLong();
+                concurrentQueryCurrent = in.readVLong();
+                queryConcurrency = in.readVLong();
+            }
         }
 
         public void add(Stats stats) {
@@ -125,6 +259,11 @@ public void add(Stats stats) {
             queryTimeInMillis += stats.queryTimeInMillis;
             queryCurrent += stats.queryCurrent;
 
+            concurrentQueryCount += stats.concurrentQueryCount;
+            concurrentQueryTimeInMillis += stats.concurrentQueryTimeInMillis;
+            concurrentQueryCurrent += stats.concurrentQueryCurrent;
+            queryConcurrency += stats.queryConcurrency;
+
             fetchCount += stats.fetchCount;
             fetchTimeInMillis += stats.fetchTimeInMillis;
             fetchCurrent += stats.fetchCurrent;
@@ -136,12 +275,19 @@ public void add(Stats stats) {
             suggestCount += stats.suggestCount;
             suggestTimeInMillis += stats.suggestTimeInMillis;
             suggestCurrent += stats.suggestCurrent;
+
+            pitCount += stats.pitCount;
+            pitTimeInMillis += stats.pitTimeInMillis;
+            pitCurrent += stats.pitCurrent;
         }
 
         public void addForClosingShard(Stats stats) {
             queryCount += stats.queryCount;
             queryTimeInMillis += stats.queryTimeInMillis;
 
+            concurrentQueryCount += stats.concurrentQueryCount;
+            concurrentQueryTimeInMillis += stats.concurrentQueryTimeInMillis;
+
             fetchCount += stats.fetchCount;
             fetchTimeInMillis += stats.fetchTimeInMillis;
 
@@ -152,6 +298,11 @@ public void addForClosingShard(Stats stats) {
 
             suggestCount += stats.suggestCount;
             suggestTimeInMillis += stats.suggestTimeInMillis;
+
+            pitCount += stats.pitCount;
+            pitTimeInMillis += stats.pitTimeInMillis;
+            pitCurrent += stats.pitCurrent;
+            queryConcurrency += stats.queryConcurrency;
         }
 
         public long getQueryCount() {
@@ -170,6 +321,30 @@ public long getQueryCurrent() {
             return queryCurrent;
         }
 
+        public long getConcurrentQueryCount() {
+            return concurrentQueryCount;
+        }
+
+        public TimeValue getConcurrentQueryTime() {
+            return new TimeValue(concurrentQueryTimeInMillis);
+        }
+
+        public double getConcurrentAvgSliceCount() {
+            if (concurrentQueryCount == 0) {
+                return 0;
+            } else {
+                return queryConcurrency / (double) concurrentQueryCount;
+            }
+        }
+
+        public long getConcurrentQueryTimeInMillis() {
+            return concurrentQueryTimeInMillis;
+        }
+
+        public long getConcurrentQueryCurrent() {
+            return concurrentQueryCurrent;
+        }
+
         public long getFetchCount() {
             return fetchCount;
         }
@@ -202,6 +377,22 @@ public long getScrollCurrent() {
             return scrollCurrent;
         }
 
+        public long getPitCount() {
+            return pitCount;
+        }
+
+        public TimeValue getPitTime() {
+            return new TimeValue(pitTimeInMillis);
+        }
+
+        public long getPitTimeInMillis() {
+            return pitTimeInMillis;
+        }
+
+        public long getPitCurrent() {
+            return pitCurrent;
+        }
+
         public long getSuggestCount() {
             return suggestCount;
         }
@@ -239,6 +430,30 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeVLong(suggestCount);
             out.writeVLong(suggestTimeInMillis);
             out.writeVLong(suggestCurrent);
+
+            if (out.getVersion().onOrAfter(Version.V_2_4_0)) {
+                out.writeVLong(pitCount);
+                out.writeVLong(pitTimeInMillis);
+                out.writeVLong(pitCurrent);
+            }
+
+            if (out.getVersion().onOrAfter(Version.V_2_11_0)) {
+                if (requestStatsLongHolder == null) {
+                    requestStatsLongHolder = new RequestStatsLongHolder();
+                }
+                out.writeMap(
+                    requestStatsLongHolder.getRequestStatsHolder(),
+                    StreamOutput::writeString,
+                    (stream, stats) -> stats.writeTo(stream)
+                );
+            }
+
+            if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+                out.writeVLong(concurrentQueryCount);
+                out.writeVLong(concurrentQueryTimeInMillis);
+                out.writeVLong(concurrentQueryCurrent);
+                out.writeVLong(queryConcurrency);
+            }
         }
 
         @Override
@@ -247,6 +462,13 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.humanReadableField(Fields.QUERY_TIME_IN_MILLIS, Fields.QUERY_TIME, getQueryTime());
             builder.field(Fields.QUERY_CURRENT, queryCurrent);
 
+            if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+                builder.field(Fields.CONCURRENT_QUERY_TOTAL, concurrentQueryCount);
+                builder.humanReadableField(Fields.CONCURRENT_QUERY_TIME_IN_MILLIS, Fields.CONCURRENT_QUERY_TIME, getConcurrentQueryTime());
+                builder.field(Fields.CONCURRENT_QUERY_CURRENT, concurrentQueryCurrent);
+                builder.field(Fields.CONCURRENT_AVG_SLICE_COUNT, getConcurrentAvgSliceCount());
+            }
+
             builder.field(Fields.FETCH_TOTAL, fetchCount);
             builder.humanReadableField(Fields.FETCH_TIME_IN_MILLIS, Fields.FETCH_TIME, getFetchTime());
             builder.field(Fields.FETCH_CURRENT, fetchCurrent);
@@ -255,10 +477,30 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.humanReadableField(Fields.SCROLL_TIME_IN_MILLIS, Fields.SCROLL_TIME, getScrollTime());
             builder.field(Fields.SCROLL_CURRENT, scrollCurrent);
 
+            builder.field(Fields.PIT_TOTAL, pitCount);
+            builder.humanReadableField(Fields.PIT_TIME_IN_MILLIS, Fields.PIT_TIME, getPitTime());
+            builder.field(Fields.PIT_CURRENT, pitCurrent);
+
             builder.field(Fields.SUGGEST_TOTAL, suggestCount);
             builder.humanReadableField(Fields.SUGGEST_TIME_IN_MILLIS, Fields.SUGGEST_TIME, getSuggestTime());
             builder.field(Fields.SUGGEST_CURRENT, suggestCurrent);
 
+            if (requestStatsLongHolder != null) {
+                builder.startObject(Fields.REQUEST);
+
+                for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+                    PhaseStatsLongHolder statsLongHolder = requestStatsLongHolder.requestStatsHolder.get(searchPhaseName.getName());
+                    if (statsLongHolder == null) {
+                        continue;
+                    }
+                    builder.startObject(searchPhaseName.getName());
+                    builder.humanReadableField(Fields.TIME_IN_MILLIS, Fields.TIME, new TimeValue(statsLongHolder.timeInMillis));
+                    builder.field(Fields.CURRENT, statsLongHolder.current);
+                    builder.field(Fields.TOTAL, statsLongHolder.total);
+                    builder.endObject();
+                }
+                builder.endObject();
+            }
             return builder;
         }
     }
@@ -273,6 +515,24 @@ public SearchStats() {
         totalStats = new Stats();
     }
 
+    // Set the different Request Stats fields in here
+    public void setSearchRequestStats(SearchRequestStats searchRequestStats) {
+        if (totalStats.requestStatsLongHolder == null) {
+            totalStats.requestStatsLongHolder = new RequestStatsLongHolder();
+        }
+
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            totalStats.requestStatsLongHolder.requestStatsHolder.put(
+                searchPhaseName.getName(),
+                new PhaseStatsLongHolder(
+                    searchRequestStats.getPhaseCurrent(searchPhaseName),
+                    searchRequestStats.getPhaseTotal(searchPhaseName),
+                    searchRequestStats.getPhaseMetric(searchPhaseName)
+                )
+            );
+        }
+    }
+
     public SearchStats(Stats totalStats, long openContexts, @Nullable Map<String, Stats> groupStats) {
         this.totalStats = totalStats;
         this.openContexts = openContexts;
@@ -351,9 +611,14 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
+    /**
+     * Fields for search statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String SEARCH = "search";
         static final String OPEN_CONTEXTS = "open_contexts";
@@ -362,6 +627,11 @@ static final class Fields {
         static final String QUERY_TIME = "query_time";
         static final String QUERY_TIME_IN_MILLIS = "query_time_in_millis";
         static final String QUERY_CURRENT = "query_current";
+        static final String CONCURRENT_QUERY_TOTAL = "concurrent_query_total";
+        static final String CONCURRENT_QUERY_TIME = "concurrent_query_time";
+        static final String CONCURRENT_QUERY_TIME_IN_MILLIS = "concurrent_query_time_in_millis";
+        static final String CONCURRENT_QUERY_CURRENT = "concurrent_query_current";
+        static final String CONCURRENT_AVG_SLICE_COUNT = "concurrent_avg_slice_count";
         static final String FETCH_TOTAL = "fetch_total";
         static final String FETCH_TIME = "fetch_time";
         static final String FETCH_TIME_IN_MILLIS = "fetch_time_in_millis";
@@ -370,10 +640,20 @@ static final class Fields {
         static final String SCROLL_TIME = "scroll_time";
         static final String SCROLL_TIME_IN_MILLIS = "scroll_time_in_millis";
         static final String SCROLL_CURRENT = "scroll_current";
+        static final String PIT_TOTAL = "point_in_time_total";
+        static final String PIT_TIME = "point_in_time_time";
+        static final String PIT_TIME_IN_MILLIS = "point_in_time_time_in_millis";
+        static final String PIT_CURRENT = "point_in_time_current";
         static final String SUGGEST_TOTAL = "suggest_total";
         static final String SUGGEST_TIME = "suggest_time";
         static final String SUGGEST_TIME_IN_MILLIS = "suggest_time_in_millis";
         static final String SUGGEST_CURRENT = "suggest_current";
+        static final String REQUEST = "request";
+        static final String TIME_IN_MILLIS = "time_in_millis";
+        static final String TIME = "time";
+        static final String CURRENT = "current";
+        static final String TOTAL = "total";
+
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/search/stats/ShardSearchStats.java b/server/src/main/java/org/opensearch/index/search/stats/ShardSearchStats.java
index 917ea99432da7..99e3f8465c5db 100644
--- a/server/src/main/java/org/opensearch/index/search/stats/ShardSearchStats.java
+++ b/server/src/main/java/org/opensearch/index/search/stats/ShardSearchStats.java
@@ -36,7 +36,7 @@
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.index.shard.SearchOperationListener;
 import org.opensearch.search.internal.ReaderContext;
 import org.opensearch.search.internal.SearchContext;
@@ -48,6 +48,11 @@
 
 import static java.util.Collections.emptyMap;
 
+/**
+ * Shard level search stats
+ *
+ * @opensearch.internal
+ */
 public final class ShardSearchStats implements SearchOperationListener {
 
     private final StatsHolder totalStats = new StatsHolder();
@@ -86,6 +91,9 @@ public void onPreQueryPhase(SearchContext searchContext) {
                 statsHolder.suggestCurrent.inc();
             } else {
                 statsHolder.queryCurrent.inc();
+                if (searchContext.shouldUseConcurrentSearch()) {
+                    statsHolder.concurrentQueryCurrent.inc();
+                }
             }
         });
     }
@@ -99,6 +107,10 @@ public void onFailedQueryPhase(SearchContext searchContext) {
             } else {
                 statsHolder.queryCurrent.dec();
                 assert statsHolder.queryCurrent.count() >= 0;
+                if (searchContext.shouldUseConcurrentSearch()) {
+                    statsHolder.concurrentQueryCurrent.dec();
+                    assert statsHolder.concurrentQueryCurrent.count() >= 0;
+                }
             }
         });
     }
@@ -114,6 +126,13 @@ public void onQueryPhase(SearchContext searchContext, long tookInNanos) {
                 statsHolder.queryMetric.inc(tookInNanos);
                 statsHolder.queryCurrent.dec();
                 assert statsHolder.queryCurrent.count() >= 0;
+                if (searchContext.shouldUseConcurrentSearch()) {
+                    statsHolder.concurrentQueryMetric.inc(tookInNanos);
+                    statsHolder.concurrentQueryCurrent.dec();
+                    assert statsHolder.concurrentQueryCurrent.count() >= 0;
+                    assert searchContext.searcher().getSlices() != null;
+                    statsHolder.queryConcurrencyMetric.inc(searchContext.searcher().getSlices().length);
+                }
             }
         });
     }
@@ -182,8 +201,27 @@ public void onFreeScrollContext(ReaderContext readerContext) {
         totalStats.scrollMetric.inc(TimeUnit.NANOSECONDS.toMicros(System.nanoTime() - readerContext.getStartTimeInNano()));
     }
 
+    @Override
+    public void onNewPitContext(ReaderContext readerContext) {
+        totalStats.pitCurrent.inc();
+    }
+
+    @Override
+    public void onFreePitContext(ReaderContext readerContext) {
+        totalStats.pitCurrent.dec();
+        assert totalStats.pitCurrent.count() >= 0;
+        totalStats.pitMetric.inc(TimeUnit.NANOSECONDS.toMicros(System.nanoTime() - readerContext.getStartTimeInNano()));
+    }
+
+    /**
+     * Holder of statistics values
+     *
+     * @opensearch.internal
+     */
     static final class StatsHolder {
         final MeanMetric queryMetric = new MeanMetric();
+        final MeanMetric concurrentQueryMetric = new MeanMetric();
+        final CounterMetric queryConcurrencyMetric = new CounterMetric();
         final MeanMetric fetchMetric = new MeanMetric();
         /* We store scroll statistics in microseconds because with nanoseconds we run the risk of overflowing the total stats if there are
          * many scrolls. For example, on a system with 2^24 scrolls that have been executed, each executing for 2^10 seconds, then using
@@ -193,10 +231,13 @@ static final class StatsHolder {
          * for one-thousand times as long (i.e., scrolls that execute for almost twelve days on average).
          */
         final MeanMetric scrollMetric = new MeanMetric();
+        final MeanMetric pitMetric = new MeanMetric();
         final MeanMetric suggestMetric = new MeanMetric();
         final CounterMetric queryCurrent = new CounterMetric();
+        final CounterMetric concurrentQueryCurrent = new CounterMetric();
         final CounterMetric fetchCurrent = new CounterMetric();
         final CounterMetric scrollCurrent = new CounterMetric();
+        final CounterMetric pitCurrent = new CounterMetric();
         final CounterMetric suggestCurrent = new CounterMetric();
 
         SearchStats.Stats stats() {
@@ -204,12 +245,19 @@ SearchStats.Stats stats() {
                 queryMetric.count(),
                 TimeUnit.NANOSECONDS.toMillis(queryMetric.sum()),
                 queryCurrent.count(),
+                concurrentQueryMetric.count(),
+                TimeUnit.NANOSECONDS.toMillis(concurrentQueryMetric.sum()),
+                concurrentQueryCurrent.count(),
+                queryConcurrencyMetric.count(),
                 fetchMetric.count(),
                 TimeUnit.NANOSECONDS.toMillis(fetchMetric.sum()),
                 fetchCurrent.count(),
                 scrollMetric.count(),
                 TimeUnit.MICROSECONDS.toMillis(scrollMetric.sum()),
                 scrollCurrent.count(),
+                pitMetric.count(),
+                TimeUnit.MICROSECONDS.toMillis(pitMetric.sum()),
+                pitCurrent.count(),
                 suggestMetric.count(),
                 TimeUnit.NANOSECONDS.toMillis(suggestMetric.sum()),
                 suggestCurrent.count()
diff --git a/server/src/main/java/org/opensearch/index/search/stats/package-info.java b/server/src/main/java/org/opensearch/index/search/stats/package-info.java
new file mode 100644
index 0000000000000..9b664d5619ce0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/search/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes for obtaining search statistics */
+package org.opensearch.index.search.stats;
diff --git a/server/src/main/java/org/opensearch/index/seqno/CountedBitSet.java b/server/src/main/java/org/opensearch/index/seqno/CountedBitSet.java
index 1bccfc4047fad..2f40b0bc8b0c6 100644
--- a/server/src/main/java/org/opensearch/index/seqno/CountedBitSet.java
+++ b/server/src/main/java/org/opensearch/index/seqno/CountedBitSet.java
@@ -39,6 +39,8 @@
  * A {@link CountedBitSet} wraps a {@link FixedBitSet} but automatically releases the internal bitset
  * when all bits are set to reduce memory usage. This structure can work well for sequence numbers as
  * these numbers are likely to form contiguous ranges (eg. filling all bits).
+ *
+ * @opensearch.internal
  */
 public final class CountedBitSet {
     static final long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(CountedBitSet.class);
diff --git a/server/src/main/java/org/opensearch/index/seqno/GlobalCheckpointSyncAction.java b/server/src/main/java/org/opensearch/index/seqno/GlobalCheckpointSyncAction.java
index a46a0c0d70a4d..ca1dfe2d5ad01 100644
--- a/server/src/main/java/org/opensearch/index/seqno/GlobalCheckpointSyncAction.java
+++ b/server/src/main/java/org/opensearch/index/seqno/GlobalCheckpointSyncAction.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ReplicationRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
@@ -43,12 +42,13 @@
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
@@ -60,6 +60,8 @@
  * Background global checkpoint sync action initiated when a shard goes inactive. This is needed because while we send the global checkpoint
  * on every replication operation, after the last operation completes the global checkpoint could advance but without a follow-up operation
  * the global checkpoint will never be synced to the replicas.
+ *
+ * @opensearch.internal
  */
 public class GlobalCheckpointSyncAction extends TransportReplicationAction<
     GlobalCheckpointSyncAction.Request,
@@ -132,11 +134,17 @@ protected void shardOperationOnReplica(Request shardRequest, IndexShard replica,
 
     private void maybeSyncTranslog(final IndexShard indexShard) throws IOException {
         if (indexShard.getTranslogDurability() == Translog.Durability.REQUEST
-            && indexShard.getLastSyncedGlobalCheckpoint() < indexShard.getLastKnownGlobalCheckpoint()) {
+            && indexShard.getLastSyncedGlobalCheckpoint() < indexShard.getLastKnownGlobalCheckpoint()
+            && indexShard.isRemoteTranslogEnabled() == false) {
             indexShard.sync();
         }
     }
 
+    /**
+     * Request for checkpoint sync action
+     *
+     * @opensearch.internal
+     */
     public static final class Request extends ReplicationRequest<Request> {
 
         private Request(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/index/seqno/LocalCheckpointTracker.java b/server/src/main/java/org/opensearch/index/seqno/LocalCheckpointTracker.java
index 7aab597f8816c..5069e1f7d6ccd 100644
--- a/server/src/main/java/org/opensearch/index/seqno/LocalCheckpointTracker.java
+++ b/server/src/main/java/org/opensearch/index/seqno/LocalCheckpointTracker.java
@@ -32,14 +32,17 @@
 
 package org.opensearch.index.seqno;
 
-import com.carrotsearch.hppc.LongObjectHashMap;
 import org.opensearch.common.SuppressForbidden;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * This class generates sequences numbers and keeps track of the so-called "local checkpoint" which is the highest number for which all
  * previous sequence numbers have been processed (inclusive).
+ *
+ * @opensearch.internal
  */
 public class LocalCheckpointTracker {
 
@@ -53,13 +56,13 @@ public class LocalCheckpointTracker {
      * A collection of bit sets representing processed sequence numbers. Each sequence number is mapped to a bit set by dividing by the
      * bit set size.
      */
-    final LongObjectHashMap<CountedBitSet> processedSeqNo = new LongObjectHashMap<>();
+    final Map<Long, CountedBitSet> processedSeqNo = new HashMap<>();
 
     /**
      * A collection of bit sets representing durably persisted sequence numbers. Each sequence number is mapped to a bit set by dividing by
      * the bit set size.
      */
-    final LongObjectHashMap<CountedBitSet> persistedSeqNo = new LongObjectHashMap<>();
+    final Map<Long, CountedBitSet> persistedSeqNo = new HashMap<>();
 
     /**
      * The current local checkpoint, i.e., all sequence numbers no more than this number have been processed.
@@ -134,7 +137,25 @@ public synchronized void markSeqNoAsPersisted(final long seqNo) {
         markSeqNo(seqNo, persistedCheckpoint, persistedSeqNo);
     }
 
-    private void markSeqNo(final long seqNo, final AtomicLong checkPoint, final LongObjectHashMap<CountedBitSet> bitSetMap) {
+    /**
+     * Updates the processed sequence checkpoint to the given value.
+     *
+     * This method is only used for segment replication since indexing doesn't
+     * take place on the replica allowing us to avoid the check that all sequence numbers
+     * are consecutively processed.
+     *
+     * @param seqNo the sequence number to mark as processed
+     */
+    public synchronized void fastForwardProcessedSeqNo(final long seqNo) {
+        advanceMaxSeqNo(seqNo);
+        final long currentProcessedCheckpoint = processedCheckpoint.get();
+        if (seqNo <= currentProcessedCheckpoint) {
+            return;
+        }
+        processedCheckpoint.compareAndSet(currentProcessedCheckpoint, seqNo);
+    }
+
+    private void markSeqNo(final long seqNo, final AtomicLong checkPoint, final Map<Long, CountedBitSet> bitSetMap) {
         assert Thread.holdsLock(this);
         // make sure we track highest seen sequence number
         advanceMaxSeqNo(seqNo);
@@ -228,7 +249,7 @@ public boolean hasProcessed(final long seqNo) {
      * following the current checkpoint is processed.
      */
     @SuppressForbidden(reason = "Object#notifyAll")
-    private void updateCheckpoint(AtomicLong checkPoint, LongObjectHashMap<CountedBitSet> bitSetMap) {
+    private void updateCheckpoint(AtomicLong checkPoint, final Map<Long, CountedBitSet> bitSetMap) {
         assert Thread.holdsLock(this);
         assert getBitSetForSeqNo(bitSetMap, checkPoint.get() + 1).get(seqNoToBitSetOffset(checkPoint.get() + 1))
             : "updateCheckpoint is called but the bit following the checkpoint is not set";
@@ -274,23 +295,15 @@ private static long getBitSetKey(final long seqNo) {
         return seqNo / BIT_SET_SIZE;
     }
 
-    private CountedBitSet getBitSetForSeqNo(final LongObjectHashMap<CountedBitSet> bitSetMap, final long seqNo) {
+    private CountedBitSet getBitSetForSeqNo(final Map<Long, CountedBitSet> bitSetMap, final long seqNo) {
         assert Thread.holdsLock(this);
         final long bitSetKey = getBitSetKey(seqNo);
-        final int index = bitSetMap.indexOf(bitSetKey);
-        final CountedBitSet bitSet;
-        if (bitSetMap.indexExists(index)) {
-            bitSet = bitSetMap.indexGet(index);
-        } else {
-            bitSet = new CountedBitSet(BIT_SET_SIZE);
-            bitSetMap.indexInsert(index, bitSetKey, bitSet);
-        }
-        return bitSet;
+        return bitSetMap.computeIfAbsent(bitSetKey, k -> new CountedBitSet(BIT_SET_SIZE));
     }
 
     /**
      * Obtain the position in the bit set corresponding to the provided sequence number. The bit set corresponding to the sequence number
-     * can be obtained via {@link #getBitSetForSeqNo(LongObjectHashMap, long)}.
+     * can be obtained via {@link #getBitSetForSeqNo(Map, long)}.
      *
      * @param seqNo the sequence number to obtain the position for
      * @return the position in the bit set corresponding to the provided sequence number
diff --git a/server/src/main/java/org/opensearch/index/seqno/ReplicationTracker.java b/server/src/main/java/org/opensearch/index/seqno/ReplicationTracker.java
index 52e858bfdaa92..0e7475de67b59 100644
--- a/server/src/main/java/org/opensearch/index/seqno/ReplicationTracker.java
+++ b/server/src/main/java/org/opensearch/index/seqno/ReplicationTracker.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.index.seqno;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
-import com.carrotsearch.hppc.ObjectLongMap;
+import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -45,17 +43,24 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.gateway.WriteStateException;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.SegmentReplicationShardStats;
 import org.opensearch.index.engine.SafeCommitInfo;
 import org.opensearch.index.shard.AbstractIndexShardComponent;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.SegmentReplicationLagTimer;
 
 import java.io.IOException;
 import java.nio.file.Path;
@@ -68,6 +73,7 @@
 import java.util.Objects;
 import java.util.OptionalLong;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -84,12 +90,14 @@
  * This class is responsible for tracking the replication group with its progress and safety markers (local and global checkpoints).
  *
  * The global checkpoint is the highest sequence number for which all lower (or equal) sequence number have been processed
- * on all shards that are currently active. Since shards count as "active" when the master starts
+ * on all shards that are currently active. Since shards count as "active" when the cluster-manager starts
  * them, and before this primary shard has been notified of this fact, we also include shards that have completed recovery. These shards
  * have received all old operations via the recovery mechanism and are kept up to date by the various replications actions. The set of
  * shards that are taken into account for the global checkpoint calculation are called the "in-sync shards".
  * <p>
  * The global checkpoint is maintained by the primary shard and is replicated to all the replicas (via {@link GlobalCheckpointSyncAction}).
+ *
+ * @opensearch.internal
  */
 public class ReplicationTracker extends AbstractIndexShardComponent implements LongSupplier {
 
@@ -133,11 +141,11 @@ public class ReplicationTracker extends AbstractIndexShardComponent implements L
      * to eagerly. As consequence, some of the methods in this class are not allowed to be called while a handoff is in progress,
      * in particular {@link #markAllocationIdAsInSync}.
      *
-     * A notable exception to this is the method {@link #updateFromMaster}, which is still allowed to be called during a relocation handoff.
+     * A notable exception to this is the method {@link #updateFromClusterManager}, which is still allowed to be called during a relocation handoff.
      * The reason for this is that the handoff might fail and can be aborted (using {@link #abortRelocationHandoff}), in which case
      * it is important that the global checkpoint tracker does not miss any state updates that might happened during the handoff attempt.
      * This means, however, that the global checkpoint can still advance after the primary relocation handoff has been initiated, but only
-     * because the master could have failed some of the in-sync shard copies and marked them as stale. That is ok though, as this
+     * because the cluster-manager could have failed some of the in-sync shard copies and marked them as stale. That is ok though, as this
      * information is conveyed through cluster state updates, and the new primary relocation target will also eventually learn about those.
      */
     boolean handoffInProgress;
@@ -241,6 +249,8 @@ public class ReplicationTracker extends AbstractIndexShardComponent implements L
 
     private final Consumer<ReplicationGroup> onReplicationGroupUpdated;
 
+    private volatile ReplicationCheckpoint latestReplicationCheckpoint;
+
     /**
      * Get all retention leases tracked on this shard.
      *
@@ -620,7 +630,9 @@ public synchronized void renewPeerRecoveryRetentionLeases() {
                      * If this shard copy is tracked then we got here here via a rolling upgrade from an older version that doesn't
                      * create peer recovery retention leases for every shard copy.
                      */
-                    assert checkpoints.get(shardRouting.allocationId().getId()).tracked == false
+                    assert (checkpoints.get(shardRouting.allocationId().getId()).tracked
+                        && checkpoints.get(shardRouting.allocationId().getId()).replicated == false)
+                        || checkpoints.get(shardRouting.allocationId().getId()).tracked == false
                         || hasAllPeerRecoveryRetentionLeases == false;
                     return false;
                 }
@@ -660,6 +672,11 @@ public synchronized void renewPeerRecoveryRetentionLeases() {
         assert invariant();
     }
 
+    /**
+     * The state of the lucene checkpoint
+     *
+     * @opensearch.internal
+     */
     public static class CheckpointState implements Writeable {
 
         /**
@@ -673,20 +690,46 @@ public static class CheckpointState implements Writeable {
          */
         long globalCheckpoint;
         /**
-         * whether this shard is treated as in-sync and thus contributes to the global checkpoint calculation
+         * When a shard is in-sync, it is capable of being promoted as the primary during a failover. An in-sync shard
+         * contributes to global checkpoint calculation on the primary iff {@link CheckpointState#replicated} is true.
          */
         boolean inSync;
 
         /**
-         * whether this shard is tracked in the replication group, i.e., should receive document updates from the primary.
+         * whether this shard is tracked in the replication group and has localTranslog, i.e., should receive document updates
+         * from the primary. Tracked shards with localTranslog would have corresponding retention leases on the primary shard's
+         * {@link ReplicationTracker}.
          */
         boolean tracked;
 
-        public CheckpointState(long localCheckpoint, long globalCheckpoint, boolean inSync, boolean tracked) {
+        /**
+         * Whether the replication requests to the primary are replicated to the concerned shard or not.
+         */
+        boolean replicated;
+
+        /**
+         * The currently searchable replication checkpoint.
+         */
+        ReplicationCheckpoint visibleReplicationCheckpoint;
+
+        /**
+         * Map of ReplicationCheckpoints to ReplicationTimers.  Timers are added as new checkpoints are published, and removed when
+         * the replica is caught up.
+         */
+        Map<ReplicationCheckpoint, SegmentReplicationLagTimer> checkpointTimers;
+
+        /**
+         * The time it took to complete the most recent replication event.
+         */
+        long lastCompletedReplicationLag;
+
+        public CheckpointState(long localCheckpoint, long globalCheckpoint, boolean inSync, boolean tracked, boolean replicated) {
             this.localCheckpoint = localCheckpoint;
             this.globalCheckpoint = globalCheckpoint;
             this.inSync = inSync;
             this.tracked = tracked;
+            this.replicated = replicated;
+            this.checkpointTimers = ConcurrentCollections.newConcurrentMap();
         }
 
         public CheckpointState(StreamInput in) throws IOException {
@@ -694,6 +737,11 @@ public CheckpointState(StreamInput in) throws IOException {
             this.globalCheckpoint = in.readZLong();
             this.inSync = in.readBoolean();
             this.tracked = in.readBoolean();
+            if (in.getVersion().onOrAfter(Version.V_2_5_0)) {
+                this.replicated = in.readBoolean();
+            } else {
+                this.replicated = true;
+            }
         }
 
         @Override
@@ -702,13 +750,16 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeZLong(globalCheckpoint);
             out.writeBoolean(inSync);
             out.writeBoolean(tracked);
+            if (out.getVersion().onOrAfter(Version.V_2_5_0)) {
+                out.writeBoolean(replicated);
+            }
         }
 
         /**
          * Returns a full copy of this object
          */
         public CheckpointState copy() {
-            return new CheckpointState(localCheckpoint, globalCheckpoint, inSync, tracked);
+            return new CheckpointState(localCheckpoint, globalCheckpoint, inSync, tracked, replicated);
         }
 
         public long getLocalCheckpoint() {
@@ -730,6 +781,8 @@ public String toString() {
                 + inSync
                 + ", tracked="
                 + tracked
+                + ", replicated="
+                + replicated
                 + '}';
         }
 
@@ -743,7 +796,8 @@ public boolean equals(Object o) {
             if (localCheckpoint != that.localCheckpoint) return false;
             if (globalCheckpoint != that.globalCheckpoint) return false;
             if (inSync != that.inSync) return false;
-            return tracked == that.tracked;
+            if (tracked != that.tracked) return false;
+            return replicated == that.replicated;
         }
 
         @Override
@@ -752,6 +806,7 @@ public int hashCode() {
             result = 31 * result + Long.hashCode(globalCheckpoint);
             result = 31 * result + Boolean.hashCode(inSync);
             result = 31 * result + Boolean.hashCode(tracked);
+            result = 31 * result + Boolean.hashCode(replicated);
             return result;
         }
     }
@@ -761,13 +816,13 @@ public int hashCode() {
      *
      * @return a map from allocation ID to the local knowledge of the persisted global checkpoint for that allocation ID
      */
-    public synchronized ObjectLongMap<String> getInSyncGlobalCheckpoints() {
+    public synchronized Map<String, Long> getInSyncGlobalCheckpoints() {
         assert primaryMode;
         assert handoffInProgress == false;
-        final ObjectLongMap<String> globalCheckpoints = new ObjectLongHashMap<>(checkpoints.size()); // upper bound on the size
+        final Map<String, Long> globalCheckpoints = new HashMap<>(checkpoints.size()); // upper bound on the size
         checkpoints.entrySet()
             .stream()
-            .filter(e -> e.getValue().inSync)
+            .filter(e -> e.getValue().inSync && e.getValue().replicated)
             .forEach(e -> globalCheckpoints.put(e.getKey(), e.getValue().globalCheckpoint));
         return globalCheckpoints;
     }
@@ -826,6 +881,9 @@ private boolean invariant() {
         // the current shard is marked as in-sync when the global checkpoint tracker operates in primary mode
         assert !primaryMode || checkpoints.get(shardAllocationId).inSync;
 
+        // the current shard is marked as tracked when the global checkpoint tracker operates in primary mode
+        assert !primaryMode || checkpoints.get(shardAllocationId).tracked;
+
         // the routing table and replication group is set when the global checkpoint tracker operates in primary mode
         assert !primaryMode || (routingTable != null && replicationGroup != null) : "primary mode but routing table is "
             + routingTable
@@ -895,7 +953,8 @@ private boolean invariant() {
         if (primaryMode && indexSettings.isSoftDeleteEnabled() && hasAllPeerRecoveryRetentionLeases) {
             // all tracked shard copies have a corresponding peer-recovery retention lease
             for (final ShardRouting shardRouting : routingTable.assignedShards()) {
-                if (checkpoints.get(shardRouting.allocationId().getId()).tracked) {
+                final CheckpointState cps = checkpoints.get(shardRouting.allocationId().getId());
+                if (cps.tracked && cps.replicated) {
                     assert retentionLeases.contains(getPeerRecoveryRetentionLeaseId(shardRouting))
                         : "no retention lease for tracked shard [" + shardRouting + "] in " + retentionLeases;
                     assert PEER_RECOVERY_RETENTION_LEASE_SOURCE.equals(
@@ -919,7 +978,11 @@ private static long inSyncCheckpointStates(
         Function<LongStream, OptionalLong> reducer
     ) {
         final OptionalLong value = reducer.apply(
-            checkpoints.values().stream().filter(cps -> cps.inSync).mapToLong(function).filter(v -> v != SequenceNumbers.UNASSIGNED_SEQ_NO)
+            checkpoints.values()
+                .stream()
+                .filter(cps -> cps.inSync && cps.replicated)
+                .mapToLong(function)
+                .filter(v -> v != SequenceNumbers.UNASSIGNED_SEQ_NO)
         );
         return value.isPresent() ? value.getAsLong() : SequenceNumbers.UNASSIGNED_SEQ_NO;
     }
@@ -995,6 +1058,7 @@ public ReplicationTracker(
         this.fileBasedRecoveryThreshold = IndexSettings.FILE_BASED_RECOVERY_THRESHOLD_SETTING.get(indexSettings.getSettings());
         this.safeCommitInfoSupplier = safeCommitInfoSupplier;
         this.onReplicationGroupUpdated = onReplicationGroupUpdated;
+        this.latestReplicationCheckpoint = indexSettings.isSegRepEnabled() ? ReplicationCheckpoint.empty(shardId) : null;
         assert Version.V_EMPTY.equals(indexSettings.getIndexVersionCreated()) == false;
         assert invariant();
     }
@@ -1023,6 +1087,11 @@ private ReplicationGroup calculateReplicationGroup() {
         } else {
             newVersion = replicationGroup.getVersion() + 1;
         }
+
+        assert indexSettings().isRemoteTranslogStoreEnabled()
+            || checkpoints.entrySet().stream().filter(e -> e.getValue().tracked).allMatch(e -> e.getValue().replicated)
+            : "In absence of remote translog store, all tracked shards must have replication mode as LOGICAL_REPLICATION";
+
         return new ReplicationGroup(
             routingTable,
             checkpoints.entrySet().stream().filter(e -> e.getValue().inSync).map(Map.Entry::getKey).collect(Collectors.toSet()),
@@ -1094,6 +1163,159 @@ public synchronized void updateGlobalCheckpointForShard(final String allocationI
         assert invariant();
     }
 
+    /**
+     * Update the local knowledge of the visible checkpoint for the specified allocation ID.
+     *
+     * This method will also stop timers for each shard and compute replication lag metrics.
+     *
+     * @param allocationId     the allocation ID to update the global checkpoint for
+     * @param visibleCheckpoint the visible checkpoint
+     */
+    public synchronized void updateVisibleCheckpointForShard(final String allocationId, final ReplicationCheckpoint visibleCheckpoint) {
+        assert indexSettings.isSegRepEnabled();
+        assert primaryMode;
+        assert handoffInProgress == false;
+        assert invariant();
+        final CheckpointState cps = checkpoints.get(allocationId);
+        assert !this.shardAllocationId.equals(allocationId);
+        // Ignore if the cps is null (i.e. replica shard not in active state).
+        if (cps == null) {
+            logger.warn("Ignoring the checkpoint update for allocation ID {} as its not being tracked by primary", allocationId);
+            return;
+        }
+        if (cps.checkpointTimers.isEmpty() == false) {
+            // stop any timers for checkpoints up to the received cp and remove from cps.checkpointTimers.
+            // Compute the max lag from the set of completed timers.
+            final AtomicLong lastFinished = new AtomicLong(0L);
+            cps.checkpointTimers.entrySet().removeIf((entry) -> {
+                boolean result = entry.getKey().isAheadOf(visibleCheckpoint) == false;
+                if (result) {
+                    final SegmentReplicationLagTimer timer = entry.getValue();
+                    timer.stop();
+                    lastFinished.set(Math.max(lastFinished.get(), timer.totalElapsedTime()));
+                }
+                return result;
+            });
+            cps.lastCompletedReplicationLag = lastFinished.get();
+        }
+        logger.trace(
+            () -> new ParameterizedMessage(
+                "updated local knowledge for [{}] on the primary of the visible checkpoint from [{}] to [{}], active timers {}",
+                allocationId,
+                cps.visibleReplicationCheckpoint,
+                visibleCheckpoint,
+                cps.checkpointTimers.keySet()
+            )
+        );
+        cps.visibleReplicationCheckpoint = visibleCheckpoint;
+        assert invariant();
+    }
+
+    /**
+     * After a new checkpoint is published, create a timer for each replica to the checkpoint.
+     * @param checkpoint {@link ReplicationCheckpoint}
+     */
+    public synchronized void setLatestReplicationCheckpoint(ReplicationCheckpoint checkpoint) {
+        assert indexSettings.isSegRepEnabled();
+        if (checkpoint.equals(latestReplicationCheckpoint) == false) {
+            this.latestReplicationCheckpoint = checkpoint;
+        }
+        if (primaryMode) {
+            createReplicationLagTimers();
+        }
+    }
+
+    public ReplicationCheckpoint getLatestReplicationCheckpoint() {
+        return this.latestReplicationCheckpoint;
+    }
+
+    private void createReplicationLagTimers() {
+        for (Map.Entry<String, CheckpointState> entry : checkpoints.entrySet()) {
+            final String allocationId = entry.getKey();
+            if (allocationId.equals(this.shardAllocationId) == false) {
+                final CheckpointState cps = entry.getValue();
+                // if the shard is in checkpoints but is unavailable or out of sync we will not track its replication state.
+                // it is possible for a shard to be in-sync but not yet removed from the checkpoints collection after a failover event.
+                if (cps.inSync
+                    && replicationGroup.getUnavailableInSyncShards().contains(allocationId) == false
+                    && latestReplicationCheckpoint.isAheadOf(cps.visibleReplicationCheckpoint)) {
+                    cps.checkpointTimers.computeIfAbsent(latestReplicationCheckpoint, ignored -> new SegmentReplicationLagTimer());
+                    logger.trace(
+                        () -> new ParameterizedMessage(
+                            "updated last published checkpoint for {} at visible cp {} to {} - timers [{}]",
+                            allocationId,
+                            cps.visibleReplicationCheckpoint,
+                            latestReplicationCheckpoint,
+                            cps.checkpointTimers.keySet()
+                        )
+                    );
+                }
+            }
+        }
+    }
+
+    /**
+     * After a new checkpoint is published, start a timer per replica for the checkpoint.
+     * @param checkpoint {@link ReplicationCheckpoint}
+     */
+    public synchronized void startReplicationLagTimers(ReplicationCheckpoint checkpoint) {
+        assert indexSettings.isSegRepEnabled();
+        if (checkpoint.equals(latestReplicationCheckpoint) == false) {
+            this.latestReplicationCheckpoint = checkpoint;
+        }
+        if (primaryMode) {
+            checkpoints.entrySet().stream().filter(e -> !e.getKey().equals(this.shardAllocationId)).forEach(e -> {
+                String allocationId = e.getKey();
+                final CheckpointState cps = e.getValue();
+                if (cps.inSync
+                    && replicationGroup.getUnavailableInSyncShards().contains(allocationId) == false
+                    && latestReplicationCheckpoint.isAheadOf(cps.visibleReplicationCheckpoint)
+                    && cps.checkpointTimers.containsKey(latestReplicationCheckpoint)) {
+                    cps.checkpointTimers.get(latestReplicationCheckpoint).start();
+                }
+            });
+        }
+    }
+
+    /**
+     * Fetch stats on segment replication.
+     * @return {@link Tuple} V1 - TimeValue in ms - mean replication lag for this primary to its entire group,
+     * V2 - Set of {@link SegmentReplicationShardStats} per shard in this primary's replication group.
+     */
+    public synchronized Set<SegmentReplicationShardStats> getSegmentReplicationStats() {
+        assert indexSettings.isSegRepEnabled();
+        if (primaryMode) {
+            return this.checkpoints.entrySet()
+                .stream()
+                // filter out this shard's allocation id, any shards that are out of sync or unavailable (shard marked in-sync but has not
+                // been assigned to a node).
+                .filter(
+                    entry -> entry.getKey().equals(this.shardAllocationId) == false
+                        && entry.getValue().inSync
+                        && replicationGroup.getUnavailableInSyncShards().contains(entry.getKey()) == false
+                )
+                .map(entry -> buildShardStats(entry.getKey(), entry.getValue()))
+                .collect(Collectors.toUnmodifiableSet());
+        }
+        return Collections.emptySet();
+    }
+
+    private SegmentReplicationShardStats buildShardStats(final String allocationId, final CheckpointState cps) {
+        final Store.RecoveryDiff diff = Store.segmentReplicationDiff(
+            latestReplicationCheckpoint.getMetadataMap(),
+            cps.visibleReplicationCheckpoint != null ? cps.visibleReplicationCheckpoint.getMetadataMap() : Collections.emptyMap()
+        );
+        final long bytesBehind = diff.missing.stream().mapToLong(StoreFileMetadata::length).sum();
+        return new SegmentReplicationShardStats(
+            allocationId,
+            cps.checkpointTimers.size(),
+            bytesBehind,
+            cps.checkpointTimers.values().stream().mapToLong(SegmentReplicationLagTimer::time).max().orElse(0),
+            cps.checkpointTimers.values().stream().mapToLong(SegmentReplicationLagTimer::totalElapsedTime).max().orElse(0),
+            cps.lastCompletedReplicationLag
+        );
+    }
+
     /**
      * Initializes the global checkpoint tracker in primary mode (see {@link #primaryMode}. Called on primary activation or promotion.
      */
@@ -1117,10 +1339,11 @@ public synchronized void activatePrimaryMode(final long localCheckpoint) {
     }
 
     /**
-     * Creates a peer recovery retention lease for this shard, if one does not already exist and this shard is the sole shard copy in the
-     * replication group. If one does not already exist and yet there are other shard copies in this group then we must have just done
-     * a rolling upgrade from a version before {@link LegacyESVersion#V_7_4_0}, in which case the missing leases should be created
-     * asynchronously by the caller using {@link ReplicationTracker#createMissingPeerRecoveryRetentionLeases(ActionListener)}.
+     * Creates a peer recovery retention lease for this shard, if one does not already exist and this shard is the sole
+     * shard copy with local translog in the replication group. If one does not already exist and yet there are other
+     * shard copies in this group then we must have just done a rolling upgrade from a version before {@code LegacyESVersion#V_7_4_0},
+     * in which case the missing leases should be created asynchronously by the caller using
+     * {@link ReplicationTracker#createMissingPeerRecoveryRetentionLeases(ActionListener)}.
      */
     private void addPeerRecoveryRetentionLeaseForSolePrimary() {
         assert primaryMode;
@@ -1129,7 +1352,8 @@ private void addPeerRecoveryRetentionLeaseForSolePrimary() {
         final ShardRouting primaryShard = routingTable.primaryShard();
         final String leaseId = getPeerRecoveryRetentionLeaseId(primaryShard);
         if (retentionLeases.get(leaseId) == null) {
-            if (replicationGroup.getReplicationTargets().equals(Collections.singletonList(primaryShard))) {
+            if (replicationGroup.getReplicationTargets().equals(Collections.singletonList(primaryShard))
+                || indexSettings().isRemoteTranslogStoreEnabled()) {
                 assert primaryShard.allocationId().getId().equals(shardAllocationId) : routingTable.assignedShards()
                     + " vs "
                     + shardAllocationId;
@@ -1165,25 +1389,25 @@ private void addPeerRecoveryRetentionLeaseForSolePrimary() {
 
     /**
      * Notifies the tracker of the current allocation IDs in the cluster state.
-     * @param applyingClusterStateVersion the cluster state version being applied when updating the allocation IDs from the master
+     * @param applyingClusterStateVersion the cluster state version being applied when updating the allocation IDs from the cluster-manager
      * @param inSyncAllocationIds         the allocation IDs of the currently in-sync shard copies
      * @param routingTable                the shard routing table
      */
-    public synchronized void updateFromMaster(
+    public synchronized void updateFromClusterManager(
         final long applyingClusterStateVersion,
         final Set<String> inSyncAllocationIds,
         final IndexShardRoutingTable routingTable
     ) {
         assert invariant();
         if (applyingClusterStateVersion > appliedClusterStateVersion) {
-            // check that the master does not fabricate new in-sync entries out of thin air once we are in primary mode
+            // check that the cluster-manager does not fabricate new in-sync entries out of thin air once we are in primary mode
             assert !primaryMode
                 || inSyncAllocationIds.stream().allMatch(inSyncId -> checkpoints.containsKey(inSyncId) && checkpoints.get(inSyncId).inSync)
-                : "update from master in primary mode contains in-sync ids "
+                : "update from cluster-manager in primary mode contains in-sync ids "
                     + inSyncAllocationIds
                     + " that have no matching entries in "
                     + checkpoints;
-            // remove entries which don't exist on master
+            // remove entries which don't exist on cluster-manager
             Set<String> initializingAllocationIds = routingTable.getAllInitializingShards()
                 .stream()
                 .map(ShardRouting::allocationId)
@@ -1192,17 +1416,32 @@ public synchronized void updateFromMaster(
             boolean removedEntries = checkpoints.keySet()
                 .removeIf(aid -> !inSyncAllocationIds.contains(aid) && !initializingAllocationIds.contains(aid));
 
+            final ShardRouting primary = routingTable.primaryShard();
+            final String primaryAllocationId = primary.allocationId().getId();
+            final String primaryTargetAllocationId = primary.relocating()
+                ? primary.getTargetRelocatingShard().allocationId().getId()
+                : null;
+
             if (primaryMode) {
                 // add new initializingIds that are missing locally. These are fresh shard copies - and not in-sync
                 for (String initializingId : initializingAllocationIds) {
                     if (checkpoints.containsKey(initializingId) == false) {
                         final boolean inSync = inSyncAllocationIds.contains(initializingId);
-                        assert inSync == false : "update from master in primary mode has "
+                        assert inSync == false : "update from cluster-manager in primary mode has "
                             + initializingId
                             + " as in-sync but it does not exist locally";
                         final long localCheckpoint = SequenceNumbers.UNASSIGNED_SEQ_NO;
                         final long globalCheckpoint = localCheckpoint;
-                        checkpoints.put(initializingId, new CheckpointState(localCheckpoint, globalCheckpoint, inSync, inSync));
+                        checkpoints.put(
+                            initializingId,
+                            new CheckpointState(
+                                localCheckpoint,
+                                globalCheckpoint,
+                                inSync,
+                                inSync,
+                                isReplicated(initializingId, primaryAllocationId, primaryTargetAllocationId)
+                            )
+                        );
                     }
                 }
                 if (removedEntries) {
@@ -1212,12 +1451,30 @@ public synchronized void updateFromMaster(
                 for (String initializingId : initializingAllocationIds) {
                     final long localCheckpoint = SequenceNumbers.UNASSIGNED_SEQ_NO;
                     final long globalCheckpoint = localCheckpoint;
-                    checkpoints.put(initializingId, new CheckpointState(localCheckpoint, globalCheckpoint, false, false));
+                    checkpoints.put(
+                        initializingId,
+                        new CheckpointState(
+                            localCheckpoint,
+                            globalCheckpoint,
+                            false,
+                            false,
+                            isReplicated(initializingId, primaryAllocationId, primaryTargetAllocationId)
+                        )
+                    );
                 }
                 for (String inSyncId : inSyncAllocationIds) {
                     final long localCheckpoint = SequenceNumbers.UNASSIGNED_SEQ_NO;
                     final long globalCheckpoint = localCheckpoint;
-                    checkpoints.put(inSyncId, new CheckpointState(localCheckpoint, globalCheckpoint, true, true));
+                    checkpoints.put(
+                        inSyncId,
+                        new CheckpointState(
+                            localCheckpoint,
+                            globalCheckpoint,
+                            true,
+                            true,
+                            isReplicated(inSyncId, primaryAllocationId, primaryTargetAllocationId)
+                        )
+                    );
                 }
             }
             appliedClusterStateVersion = applyingClusterStateVersion;
@@ -1232,6 +1489,42 @@ public synchronized void updateFromMaster(
         assert invariant();
     }
 
+    /**
+     * Returns whether the requests are replicated considering the remote translog existence, current/primary/primary target allocation ids.
+     *
+     * @param allocationId              given allocation id
+     * @param primaryAllocationId       primary allocation id
+     * @param primaryTargetAllocationId primary target allocation id
+     * @return the replication mode.
+     */
+    private boolean isReplicated(String allocationId, String primaryAllocationId, String primaryTargetAllocationId) {
+        // If remote translog is enabled, then returns replication mode checking current allocation id against the
+        // primary and primary target allocation id.
+        // If remote translog is enabled, then returns true if given allocation id matches the primary or it's relocation target allocation
+        // id.
+        if (indexSettings().isRemoteTranslogStoreEnabled()) {
+            return (allocationId.equals(primaryAllocationId) || allocationId.equals(primaryTargetAllocationId));
+        }
+        // For other case which is local translog, return true as the requests are replicated to all shards in the replication group.
+        return true;
+    }
+
+    /**
+     * Notifies the tracker of the current allocation IDs in the cluster state.
+     * @param applyingClusterStateVersion the cluster state version being applied when updating the allocation IDs from the cluster-manager
+     * @param inSyncAllocationIds         the allocation IDs of the currently in-sync shard copies
+     * @param routingTable                the shard routing table
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #updateFromClusterManager(long, Set, IndexShardRoutingTable)}
+     */
+    @Deprecated
+    public synchronized void updateFromMaster(
+        final long applyingClusterStateVersion,
+        final Set<String> inSyncAllocationIds,
+        final IndexShardRoutingTable routingTable
+    ) {
+        updateFromClusterManager(applyingClusterStateVersion, inSyncAllocationIds, routingTable);
+    }
+
     /**
      * Called when the recovery process for a shard has opened the engine on the target shard. Ensures that the right data structures
      * have been set up locally to track local checkpoint information for the shard and that the shard is added to the replication group.
@@ -1277,13 +1570,14 @@ public synchronized void markAllocationIdAsInSync(final String allocationId, fin
         updateLocalCheckpoint(allocationId, cps, localCheckpoint);
         // if it was already in-sync (because of a previously failed recovery attempt), global checkpoint must have been
         // stuck from advancing
-        assert !cps.inSync || (cps.localCheckpoint >= getGlobalCheckpoint()) : "shard copy "
+        assert !cps.inSync || cps.localCheckpoint >= getGlobalCheckpoint() || cps.replicated == false : "shard copy "
             + allocationId
             + " that's already in-sync should have a local checkpoint "
             + cps.localCheckpoint
             + " that's above the global checkpoint "
-            + getGlobalCheckpoint();
-        if (cps.localCheckpoint < getGlobalCheckpoint()) {
+            + getGlobalCheckpoint()
+            + " or it's not replicated";
+        if (cps.replicated && cps.localCheckpoint < getGlobalCheckpoint()) {
             pendingInSync.add(allocationId);
             try {
                 while (true) {
@@ -1354,7 +1648,7 @@ public synchronized void updateLocalCheckpoint(final String allocationId, final
             logger.trace("marked [{}] as in-sync", allocationId);
             notifyAllWaiters();
         }
-        if (increasedLocalCheckpoint && pending == false) {
+        if (cps.replicated && increasedLocalCheckpoint && pending == false) {
             updateGlobalCheckpointOnPrimary();
         }
         assert invariant();
@@ -1374,7 +1668,7 @@ private static long computeGlobalCheckpoint(
             return fallback;
         }
         for (final CheckpointState cps : localCheckpoints) {
-            if (cps.inSync) {
+            if (cps.inSync && cps.replicated) {
                 if (cps.localCheckpoint == SequenceNumbers.UNASSIGNED_SEQ_NO) {
                     // unassigned in-sync replica
                     return fallback;
@@ -1475,7 +1769,7 @@ public synchronized void activateWithPrimaryContext(PrimaryContext primaryContex
             assert indexSettings.getIndexVersionCreated().before(LegacyESVersion.V_7_3_0);
             throw new IllegalStateException("primary context [" + primaryContext + "] does not contain " + shardAllocationId);
         }
-        final Runnable runAfter = getMasterUpdateOperationFromCurrentState();
+        final Runnable runAfter = getClusterManagerUpdateOperationFromCurrentState();
         primaryMode = true;
         // capture current state to possibly replay missed cluster state update
         appliedClusterStateVersion = primaryContext.clusterStateVersion();
@@ -1541,7 +1835,7 @@ public synchronized void createMissingPeerRecoveryRetentionLeases(ActionListener
         }
     }
 
-    private Runnable getMasterUpdateOperationFromCurrentState() {
+    private Runnable getClusterManagerUpdateOperationFromCurrentState() {
         assert primaryMode == false;
         final long lastAppliedClusterStateVersion = appliedClusterStateVersion;
         final Set<String> inSyncAllocationIds = new HashSet<>();
@@ -1551,7 +1845,7 @@ private Runnable getMasterUpdateOperationFromCurrentState() {
             }
         });
         final IndexShardRoutingTable lastAppliedRoutingTable = routingTable;
-        return () -> updateFromMaster(lastAppliedClusterStateVersion, inSyncAllocationIds, lastAppliedRoutingTable);
+        return () -> updateFromClusterManager(lastAppliedClusterStateVersion, inSyncAllocationIds, lastAppliedRoutingTable);
     }
 
     /**
@@ -1592,6 +1886,8 @@ private synchronized void waitForLocalCheckpointToAdvance() throws InterruptedEx
     /**
      * Represents the sequence number component of the primary context. This is the knowledge on the primary of the in-sync and initializing
      * shards and their local checkpoints.
+     *
+     * @opensearch.internal
      */
     public static class PrimaryContext implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLease.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLease.java
index f9ab4c4e3ff1f..216b654f6ce6a 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLease.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLease.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +50,8 @@
  * that all operations with sequence number at least that retaining sequence number will be retained during merge operations (which could
  * otherwise merge away operations that have been soft deleted). Each retention lease contains a unique identifier, the retaining sequence
  * number, the timestamp of when the lease was created or renewed, and the source of the retention lease (e.g., "ccr").
+ *
+ * @opensearch.internal
  */
 public final class RetentionLease implements ToXContentObject, Writeable {
 
@@ -189,8 +192,8 @@ public boolean isFragment() {
     }
 
     /**
-     * Parses a retention lease from {@link org.opensearch.common.xcontent.XContent}. This method assumes that the retention lease was
-     * converted to {@link org.opensearch.common.xcontent.XContent} via {@link #toXContent(XContentBuilder, Params)}.
+     * Parses a retention lease from {@link XContent}. This method assumes that the retention lease was
+     * converted to {@link XContent} via {@link #toXContent(XContentBuilder, Params)}.
      *
      * @param parser the parser
      * @return a retention lease
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseActions.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseActions.java
index 37c32e1c4409c..db8b06489f2ae 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseActions.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseActions.java
@@ -32,9 +32,7 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
@@ -44,13 +42,15 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -64,11 +64,18 @@
  * responded with success. Additionally, note the use of
  * {@link TransportSingleShardAction#asyncShardOperation(SingleShardRequest, ShardId, ActionListener)} to handle the case when acquiring
  * permits goes asynchronous because acquiring permits is blocked
+ *
+ * @opensearch.internal
  */
 public class RetentionLeaseActions {
 
     public static final long RETAIN_ALL = -1;
 
+    /**
+     * Base class for transport retention lease actions
+     *
+     * @opensearch.internal
+     */
     abstract static class TransportRetentionLeaseAction<T extends Request<T>> extends TransportSingleShardAction<T, Response> {
 
         private final IndicesService indicesService;
@@ -132,6 +139,11 @@ protected boolean resolveIndex(final T request) {
 
     }
 
+    /**
+     * Add retention lease action
+     *
+     * @opensearch.internal
+     */
     public static class Add extends ActionType<Response> {
 
         public static final Add INSTANCE = new Add();
@@ -141,6 +153,11 @@ private Add() {
             super(ACTION_NAME, Response::new);
         }
 
+        /**
+         * Internal transport action
+         *
+         * @opensearch.internal
+         */
         public static class TransportAction extends TransportRetentionLeaseAction<AddRequest> {
 
             @Inject
@@ -182,6 +199,11 @@ protected Writeable.Reader<Response> getResponseReader() {
         }
     }
 
+    /**
+     * Renew the retention lease
+     *
+     * @opensearch.internal
+     */
     public static class Renew extends ActionType<Response> {
 
         public static final Renew INSTANCE = new Renew();
@@ -191,6 +213,11 @@ private Renew() {
             super(ACTION_NAME, Response::new);
         }
 
+        /**
+         * Internal transport action for renew
+         *
+         * @opensearch.internal
+         */
         public static class TransportAction extends TransportRetentionLeaseAction<RenewRequest> {
 
             @Inject
@@ -223,6 +250,11 @@ void doRetentionLeaseAction(final IndexShard indexShard, final RenewRequest requ
         }
     }
 
+    /**
+     * Remove retention lease action
+     *
+     * @opensearch.internal
+     */
     public static class Remove extends ActionType<Response> {
 
         public static final Remove INSTANCE = new Remove();
@@ -232,6 +264,11 @@ private Remove() {
             super(ACTION_NAME, Response::new);
         }
 
+        /**
+         * Internal transport action for remove
+         *
+         * @opensearch.internal
+         */
         public static class TransportAction extends TransportRetentionLeaseAction<RemoveRequest> {
 
             @Inject
@@ -263,6 +300,11 @@ void doRetentionLeaseAction(final IndexShard indexShard, final RemoveRequest req
         }
     }
 
+    /**
+     * Base request
+     *
+     * @opensearch.internal
+     */
     private abstract static class Request<T extends SingleShardRequest<T>> extends SingleShardRequest<T> {
 
         private final ShardId shardId;
@@ -303,6 +345,11 @@ public void writeTo(final StreamOutput out) throws IOException {
 
     }
 
+    /**
+     * Base add or renew request
+     *
+     * @opensearch.internal
+     */
     private abstract static class AddOrRenewRequest<T extends SingleShardRequest<T>> extends Request<T> {
 
         private final long retainingSequenceNumber;
@@ -341,6 +388,11 @@ public void writeTo(final StreamOutput out) throws IOException {
 
     }
 
+    /**
+     * Add retention lease request
+     *
+     * @opensearch.internal
+     */
     public static class AddRequest extends AddOrRenewRequest<AddRequest> {
 
         AddRequest(StreamInput in) throws IOException {
@@ -353,6 +405,11 @@ public AddRequest(final ShardId shardId, final String id, final long retainingSe
 
     }
 
+    /**
+     * Renew Request action
+     *
+     * @opensearch.internal
+     */
     public static class RenewRequest extends AddOrRenewRequest<RenewRequest> {
 
         RenewRequest(StreamInput in) throws IOException {
@@ -365,6 +422,11 @@ public RenewRequest(final ShardId shardId, final String id, final long retaining
 
     }
 
+    /**
+     * Remove request
+     *
+     * @opensearch.internal
+     */
     public static class RemoveRequest extends Request<RemoveRequest> {
 
         RemoveRequest(StreamInput in) throws IOException {
@@ -377,6 +439,11 @@ public RemoveRequest(final ShardId shardId, final String id) {
 
     }
 
+    /**
+     * The response
+     *
+     * @opensearch.internal
+     */
     public static class Response extends ActionResponse {
 
         public Response() {}
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseAlreadyExistsException.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseAlreadyExistsException.java
index 20761621d6c16..122b8279b08f9 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseAlreadyExistsException.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseAlreadyExistsException.java
@@ -33,11 +33,16 @@
 package org.opensearch.index.seqno;
 
 import org.opensearch.ResourceAlreadyExistsException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Exception thrown if a retention lease already exists
+ *
+ * @opensearch.internal
+ */
 public class RetentionLeaseAlreadyExistsException extends ResourceAlreadyExistsException {
 
     public RetentionLeaseAlreadyExistsException(final String id) {
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncAction.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncAction.java
index 014ffedb81e3f..5fa0a1a6459e7 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncAction.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncAction.java
@@ -37,7 +37,6 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.replication.ReplicationRequest;
@@ -47,18 +46,19 @@
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportResponseHandler;
@@ -73,6 +73,8 @@
  * that if a replica misses a background retention lease sync then that shard will not be marked as stale. We have some tolerance for a
  * shard copy missing renewals of retention leases since the background sync interval is much smaller than the expected lifetime of
  * retention leases.
+ *
+ * @opensearch.internal
  */
 public class RetentionLeaseBackgroundSyncAction extends TransportReplicationAction<
     RetentionLeaseBackgroundSyncAction.Request,
@@ -196,6 +198,11 @@ protected void shardOperationOnReplica(Request request, IndexShard replica, Acti
         });
     }
 
+    /**
+     * Request for retention lease bground sync action
+     *
+     * @opensearch.internal
+     */
     public static final class Request extends ReplicationRequest<Request> {
 
         private RetentionLeases retentionLeases;
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseInvalidRetainingSeqNoException.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseInvalidRetainingSeqNoException.java
index 5231c7260a292..66af085974fa6 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseInvalidRetainingSeqNoException.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseInvalidRetainingSeqNoException.java
@@ -33,10 +33,15 @@
 package org.opensearch.index.seqno;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when an invalid sequence number is retained
+ *
+ * @opensearch.internal
+ */
 public class RetentionLeaseInvalidRetainingSeqNoException extends OpenSearchException {
 
     RetentionLeaseInvalidRetainingSeqNoException(
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseNotFoundException.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseNotFoundException.java
index 1f77206bf998c..3a1a6e1d0025b 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseNotFoundException.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseNotFoundException.java
@@ -33,11 +33,16 @@
 package org.opensearch.index.seqno;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Exception thrown when a retention lease is not found
+ *
+ * @opensearch.internal
+ */
 public class RetentionLeaseNotFoundException extends ResourceNotFoundException {
 
     public RetentionLeaseNotFoundException(final String id) {
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseStats.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseStats.java
index 77749915958be..512ef9bf4f0a5 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseStats.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseStats.java
@@ -32,17 +32,20 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Represents retention lease stats.
+ *
+ * @opensearch.internal
  */
 public final class RetentionLeaseStats implements ToXContentFragment, Writeable {
 
@@ -90,11 +93,11 @@ public void writeTo(final StreamOutput out) throws IOException {
     }
 
     /**
-     * Converts the retention lease stats to {@link org.opensearch.common.xcontent.XContent} using the specified builder and pararms.
+     * Converts the retention lease stats to {@link XContent} using the specified builder and pararms.
      *
      * @param builder the builder
      * @param params  the params
-     * @return the builder that this retention lease collection was converted to {@link org.opensearch.common.xcontent.XContent} into
+     * @return the builder that this retention lease collection was converted to {@link XContent} into
      * @throws IOException if an I/O exception occurs writing to the builder
      */
     @Override
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncAction.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncAction.java
index 55bd01df0979a..f74fc7eefe65c 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncAction.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncAction.java
@@ -37,7 +37,6 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.WriteResponse;
@@ -49,19 +48,20 @@
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportResponseHandler;
@@ -74,6 +74,8 @@
 /**
  * Write action responsible for syncing retention leases to replicas. This action is deliberately a write action so that if a replica misses
  * a retention lease sync then that shard will be marked as stale.
+ *
+ * @opensearch.internal
  */
 public class RetentionLeaseSyncAction extends TransportWriteAction<
     RetentionLeaseSyncAction.Request,
@@ -209,6 +211,11 @@ public ClusterBlockLevel indexBlockLevel() {
         return null;
     }
 
+    /**
+     * Request for retention lease sync action
+     *
+     * @opensearch.internal
+     */
     public static final class Request extends ReplicatedWriteRequest<Request> {
 
         private RetentionLeases retentionLeases;
@@ -258,6 +265,11 @@ public String toString() {
 
     }
 
+    /**
+     * Response for retention lease sync action
+     *
+     * @opensearch.internal
+     */
     public static final class Response extends ReplicationResponse implements WriteResponse {
 
         public Response() {}
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncer.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncer.java
index a8f48b0d431a5..cefab995847b7 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncer.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeaseSyncer.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Objects;
 
+/**
+ * Syncs retention leases
+ *
+ * @opensearch.internal
+ */
 public class RetentionLeaseSyncer {
     private final SyncAction syncAction;
     private final BackgroundSyncAction backgroundSyncAction;
@@ -75,6 +80,8 @@ public void backgroundSync(ShardId shardId, String primaryAllocationId, long pri
     /**
      * Represents an action that is invoked to sync retention leases to replica shards after a retention lease is added
      * or removed on the primary. The specified listener is invoked when the syncing completes with success or failure.
+     *
+     * @opensearch.internal
      */
     public interface SyncAction {
         void sync(
@@ -89,6 +96,8 @@ void sync(
     /**
      * Represents an action that is invoked periodically to sync retention leases to replica shards after some retention
      * lease has been renewed or expired.
+     *
+     * @opensearch.internal
      */
     public interface BackgroundSyncAction {
         void backgroundSync(ShardId shardId, String primaryAllocationId, long primaryTerm, RetentionLeases retentionLeases);
diff --git a/server/src/main/java/org/opensearch/index/seqno/RetentionLeases.java b/server/src/main/java/org/opensearch/index/seqno/RetentionLeases.java
index e5fef4dcffc5a..74c4ddb6ebdb5 100644
--- a/server/src/main/java/org/opensearch/index/seqno/RetentionLeases.java
+++ b/server/src/main/java/org/opensearch/index/seqno/RetentionLeases.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.MetadataStateFormat;
 
 import java.io.IOException;
@@ -55,6 +56,8 @@
 /**
  * Represents a versioned collection of retention leases. We version the collection of retention leases to ensure that sync requests that
  * arrive out of order on the replica, using the version to ensure that older sync requests are rejected.
+ *
+ * @opensearch.internal
  */
 public class RetentionLeases implements ToXContentFragment, Writeable {
 
@@ -221,8 +224,8 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
     }
 
     /**
-     * Parses a retention leases collection from {@link org.opensearch.common.xcontent.XContent}. This method assumes that the retention
-     * leases were converted to {@link org.opensearch.common.xcontent.XContent} via {@link #toXContent(XContentBuilder, Params)}.
+     * Parses a retention leases collection from {@link XContent}. This method assumes that the retention
+     * leases were converted to {@link XContent} via {@link #toXContent(XContentBuilder, Params)}.
      *
      * @param parser the parser
      * @return a retention leases collection
diff --git a/server/src/main/java/org/opensearch/index/seqno/SeqNoStats.java b/server/src/main/java/org/opensearch/index/seqno/SeqNoStats.java
index 0f26377568e17..be7888ada2801 100644
--- a/server/src/main/java/org/opensearch/index/seqno/SeqNoStats.java
+++ b/server/src/main/java/org/opensearch/index/seqno/SeqNoStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Sequence number statistics
+ *
+ * @opensearch.internal
+ */
 public class SeqNoStats implements ToXContentFragment, Writeable {
 
     private static final String SEQ_NO = "seq_no";
diff --git a/server/src/main/java/org/opensearch/index/seqno/SequenceNumbers.java b/server/src/main/java/org/opensearch/index/seqno/SequenceNumbers.java
index 3da32efe4d027..210976ffba58a 100644
--- a/server/src/main/java/org/opensearch/index/seqno/SequenceNumbers.java
+++ b/server/src/main/java/org/opensearch/index/seqno/SequenceNumbers.java
@@ -36,6 +36,8 @@
 
 /**
  * A utility class for handling sequence numbers.
+ *
+ * @opensearch.internal
  */
 public class SequenceNumbers {
 
@@ -127,6 +129,11 @@ public static long max(final long maxSeqNo, final long seqNo) {
         }
     }
 
+    /**
+     * Commit information
+     *
+     * @opensearch.internal
+     */
     public static final class CommitInfo {
         public final long maxSeqNo;
         public final long localCheckpoint;
diff --git a/server/src/main/java/org/opensearch/index/seqno/package-info.java b/server/src/main/java/org/opensearch/index/seqno/package-info.java
new file mode 100644
index 0000000000000..495cde64a67ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/seqno/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Sequence number and retention lease implementation */
+package org.opensearch.index.seqno;
diff --git a/server/src/main/java/org/opensearch/index/shard/AbstractIndexShardComponent.java b/server/src/main/java/org/opensearch/index/shard/AbstractIndexShardComponent.java
index 24f0f7aa7b730..5e973ff9acb8f 100644
--- a/server/src/main/java/org/opensearch/index/shard/AbstractIndexShardComponent.java
+++ b/server/src/main/java/org/opensearch/index/shard/AbstractIndexShardComponent.java
@@ -34,8 +34,14 @@
 
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.logging.Loggers;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base index shard class
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractIndexShardComponent implements IndexShardComponent {
 
     protected final Logger logger;
diff --git a/server/src/main/java/org/opensearch/index/shard/CheckpointRefreshListener.java b/server/src/main/java/org/opensearch/index/shard/CheckpointRefreshListener.java
new file mode 100644
index 0000000000000..85d744e58265f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/shard/CheckpointRefreshListener.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.search.ReferenceManager;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+
+import java.io.IOException;
+
+/**
+ * A {@link ReferenceManager.RefreshListener} that publishes a checkpoint to be consumed by replicas.
+ * This class is only used with Segment Replication enabled.
+ *
+ * @opensearch.internal
+ */
+public class CheckpointRefreshListener extends CloseableRetryableRefreshListener {
+
+    protected static Logger logger = LogManager.getLogger(CheckpointRefreshListener.class);
+
+    private final IndexShard shard;
+    private final SegmentReplicationCheckpointPublisher publisher;
+
+    public CheckpointRefreshListener(IndexShard shard, SegmentReplicationCheckpointPublisher publisher) {
+        this.shard = shard;
+        this.publisher = publisher;
+    }
+
+    @Override
+    public void beforeRefresh() throws IOException {
+        // Do nothing
+    }
+
+    @Override
+    protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+        if (didRefresh
+            && shard.state() == IndexShardState.STARTED
+            && shard.getReplicationTracker().isPrimaryMode()
+            && !shard.indexSettings.isSegRepWithRemoteEnabled()) {
+            publisher.publish(shard, shard.getLatestReplicationCheckpoint());
+        }
+        return true;
+    }
+
+    @Override
+    protected Logger getLogger() {
+        return logger;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/shard/CloseableRetryableRefreshListener.java b/server/src/main/java/org/opensearch/index/shard/CloseableRetryableRefreshListener.java
new file mode 100644
index 0000000000000..3ee74e5267718
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/shard/CloseableRetryableRefreshListener.java
@@ -0,0 +1,213 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.search.ReferenceManager;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Objects;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * RefreshListener that runs afterRefresh method if and only if there is a permit available. Once the listener
+ * is closed, all the permits are acquired and there are no available permits to afterRefresh. This abstract class provides
+ * necessary abstract methods to schedule retry.
+ */
+public abstract class CloseableRetryableRefreshListener implements ReferenceManager.RefreshListener, Closeable {
+
+    /**
+     * Total permits = 1 ensures that there is only single instance of runAfterRefreshWithPermit that is running at a time.
+     * In case there are use cases where concurrency is required, the total permit variable can be put inside the ctor.
+     */
+    private static final int TOTAL_PERMITS = 1;
+
+    private final AtomicBoolean closed = new AtomicBoolean(false);
+
+    private final Semaphore semaphore = new Semaphore(TOTAL_PERMITS);
+
+    private final ThreadPool threadPool;
+
+    /**
+     * This boolean is used to ensure that there is only 1 retry scheduled/running at any time.
+     */
+    private final AtomicBoolean retryScheduled = new AtomicBoolean(false);
+
+    public CloseableRetryableRefreshListener() {
+        this.threadPool = null;
+    }
+
+    public CloseableRetryableRefreshListener(ThreadPool threadPool) {
+        assert Objects.nonNull(threadPool);
+        this.threadPool = threadPool;
+    }
+
+    @Override
+    public final void afterRefresh(boolean didRefresh) throws IOException {
+        if (closed.get()) {
+            return;
+        }
+        runAfterRefreshExactlyOnce(didRefresh);
+        runAfterRefreshWithPermit(didRefresh, () -> {});
+    }
+
+    /**
+     * The code in this method is executed exactly once. This is done for running non-idempotent function which needs to be
+     * executed immediately when afterRefresh method is invoked.
+     *
+     * @param didRefresh if the refresh did open a new reference then didRefresh will be true
+     */
+    protected void runAfterRefreshExactlyOnce(boolean didRefresh) {
+        // No-op: The implementor would be providing the code
+    }
+
+    /**
+     * The implementor has the option to override the retry thread pool name. This will be used for scheduling the retries.
+     * The method would be invoked each time when a retry is required. By default, it uses the same threadpool for retry.
+     *
+     * @return the name of the retry thread pool.
+     */
+    protected String getRetryThreadPoolName() {
+        return ThreadPool.Names.SAME;
+    }
+
+    /**
+     * By default, the retry interval is returned as 1s. The implementor has the option to override the retry interval.
+     * This is used for scheduling the next retry. The method would be invoked each time when a retry is required. The
+     * implementor can choose any retry strategy and return the next retry interval accordingly.
+     *
+     * @return the interval for the next retry.
+     */
+    protected TimeValue getNextRetryInterval() {
+        return TimeValue.timeValueSeconds(1);
+    }
+
+    /**
+     * This method is used to schedule retry which internally calls the performAfterRefresh method under the available permits.
+     *
+     * @param interval            interval after which the retry would be invoked
+     * @param retryThreadPoolName the thread pool name to be used for retry
+     * @param didRefresh          if didRefresh is true
+     */
+    private void scheduleRetry(TimeValue interval, String retryThreadPoolName, boolean didRefresh) {
+        // If the underlying listener has closed, then we do not allow even the retry to be scheduled
+        if (closed.get() || isRetryEnabled() == false) {
+            getLogger().debug("skip retry on closed={} isRetryEnabled={}", closed.get(), isRetryEnabled());
+            return;
+        }
+
+        assert Objects.nonNull(interval) && ThreadPool.THREAD_POOL_TYPES.containsKey(retryThreadPoolName);
+
+        // If the retryScheduled is already true, then we return from here itself. If not, then we proceed with scheduling
+        // the retry.
+        if (retryScheduled.getAndSet(true)) {
+            getLogger().debug("skip retry on retryScheduled=true");
+            return;
+        }
+
+        boolean scheduled = false;
+        try {
+            this.threadPool.schedule(
+                () -> runAfterRefreshWithPermit(didRefresh, () -> retryScheduled.set(false)),
+                interval,
+                retryThreadPoolName
+            );
+            scheduled = true;
+            getLogger().info("Scheduled retry with didRefresh={}", didRefresh);
+        } finally {
+            if (scheduled == false) {
+                retryScheduled.set(false);
+            }
+        }
+    }
+
+    /**
+     * This returns if the retry is enabled or not. By default, the retries are not enabled.
+     * @return true if retry is enabled.
+     */
+    protected boolean isRetryEnabled() {
+        return false;
+    }
+
+    /**
+     * Runs the performAfterRefresh method under permit. If there are no permits available, then it is no-op. It also hits
+     * the scheduleRetry method with the result value of the performAfterRefresh method invocation.
+     * The synchronised block ensures that if there is a retry or afterRefresh waiting, then it waits until the previous
+     * execution finishes.
+     */
+    private synchronized void runAfterRefreshWithPermit(boolean didRefresh, Runnable runFinally) {
+        if (closed.get()) {
+            return;
+        }
+        boolean successful;
+        boolean permitAcquired = semaphore.tryAcquire();
+        try {
+            successful = permitAcquired && performAfterRefreshWithPermit(didRefresh);
+        } finally {
+            if (permitAcquired) {
+                semaphore.release();
+            }
+            runFinally.run();
+        }
+        scheduleRetry(successful, didRefresh);
+    }
+
+    /**
+     * Schedules the retry based on the {@code afterRefreshSuccessful} value.
+     *
+     * @param afterRefreshSuccessful is sent true if the performAfterRefresh(..) is successful.
+     * @param didRefresh             if the refresh did open a new reference then didRefresh will be true
+     */
+    private void scheduleRetry(boolean afterRefreshSuccessful, boolean didRefresh) {
+        if (afterRefreshSuccessful == false) {
+            scheduleRetry(getNextRetryInterval(), getRetryThreadPoolName(), didRefresh);
+        }
+    }
+
+    /**
+     * This method needs to be overridden and be provided with what needs to be run on after refresh with permits.
+     *
+     * @param didRefresh true if the refresh opened a new reference
+     * @return true if a retry is needed else false.
+     */
+    protected abstract boolean performAfterRefreshWithPermit(boolean didRefresh);
+
+    @Override
+    public final void close() throws IOException {
+        try {
+            if (semaphore.tryAcquire(TOTAL_PERMITS, 10, TimeUnit.MINUTES)) {
+                boolean result = closed.compareAndSet(false, true);
+                assert result && semaphore.availablePermits() == 0;
+                getLogger().info("All permits are acquired and refresh listener is closed");
+            } else {
+                throw new TimeoutException("timeout while closing gated refresh listener");
+            }
+        } catch (InterruptedException | TimeoutException e) {
+            throw new RuntimeException("Failed to close the closeable retryable listener", e);
+        }
+    }
+
+    protected abstract Logger getLogger();
+
+    // Visible for testing
+    /**
+     * Returns if the retry is scheduled or not.
+     *
+     * @return boolean as mentioned above.
+     */
+    boolean getRetryScheduledStatus() {
+        return retryScheduled.get();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/shard/DocsStats.java b/server/src/main/java/org/opensearch/index/shard/DocsStats.java
index e9d41ceff09e8..83cc69752db2f 100644
--- a/server/src/main/java/org/opensearch/index/shard/DocsStats.java
+++ b/server/src/main/java/org/opensearch/index/shard/DocsStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.store.StoreStats;
 
 import java.io.IOException;
 
+/**
+ * Document statistics
+ *
+ * @opensearch.internal
+ */
 public class DocsStats implements Writeable, ToXContentFragment {
 
     private long count = 0;
@@ -116,6 +121,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for document statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String DOCS = "docs";
         static final String COUNT = "count";
diff --git a/server/src/main/java/org/opensearch/index/shard/GlobalCheckpointListeners.java b/server/src/main/java/org/opensearch/index/shard/GlobalCheckpointListeners.java
index 3c8ed8ea7492a..3948baa5d5164 100644
--- a/server/src/main/java/org/opensearch/index/shard/GlobalCheckpointListeners.java
+++ b/server/src/main/java/org/opensearch/index/shard/GlobalCheckpointListeners.java
@@ -34,10 +34,11 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.Assertions;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -58,11 +59,15 @@
 /**
  * Represents a collection of global checkpoint listeners. This collection can be added to, and all listeners present at the time of an
  * update will be notified together. All listeners will be notified when the shard is closed.
+ *
+ * @opensearch.internal
  */
 public class GlobalCheckpointListeners implements Closeable {
 
     /**
      * A global checkpoint listener consisting of a callback that is notified when the global checkpoint is updated or the shard is closed.
+     *
+     * @opensearch.internal
      */
     public interface GlobalCheckpointListener {
 
diff --git a/server/src/main/java/org/opensearch/index/shard/IllegalIndexShardStateException.java b/server/src/main/java/org/opensearch/index/shard/IllegalIndexShardStateException.java
index a6cd831291e37..47ed149913914 100644
--- a/server/src/main/java/org/opensearch/index/shard/IllegalIndexShardStateException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IllegalIndexShardStateException.java
@@ -33,12 +33,18 @@
 package org.opensearch.index.shard;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when an index shard is in an illegal state
+ *
+ * @opensearch.internal
+ */
 public class IllegalIndexShardStateException extends OpenSearchException {
 
     private final IndexShardState currentState;
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexEventListener.java b/server/src/main/java/org/opensearch/index/shard/IndexEventListener.java
index 69f283a53ca79..d1cb396f55d0f 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexEventListener.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexEventListener.java
@@ -34,7 +34,8 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
@@ -49,6 +50,8 @@
  * local state via their arguments. Yet, if an instance is shared across indices they might be called concurrently and should not
  * modify local state without sufficient synchronization.
  * </p>
+ *
+ * @opensearch.internal
  */
 public interface IndexEventListener {
 
@@ -161,7 +164,7 @@ default void beforeIndexShardDeleted(ShardId shardId, Settings indexSettings) {}
     default void afterIndexShardDeleted(ShardId shardId, Settings indexSettings) {}
 
     /**
-     * Called on the Master node only before the {@link IndexService} instances is created to simulate an index creation.
+     * Called on the cluster-manager node only before the {@link IndexService} instances is created to simulate an index creation.
      * This happens right before the index and it's metadata is registered in the cluster state
      */
     default void beforeIndexAddedToCluster(Index index, Settings indexSettings) {}
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexSettingProvider.java b/server/src/main/java/org/opensearch/index/shard/IndexSettingProvider.java
index 7d1e77214640b..861a325c45d4b 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexSettingProvider.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexSettingProvider.java
@@ -32,12 +32,16 @@
 
 package org.opensearch.index.shard;
 
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.Settings;
 
 /**
  * An {@link IndexSettingProvider} is a provider for index level settings that can be set
  * explicitly as a default value (so they show up as "set" for newly created indices)
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface IndexSettingProvider {
     /**
      * Returns explicitly set default index {@link Settings} for the given index. This should not
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShard.java b/server/src/main/java/org/opensearch/index/shard/IndexShard.java
index f2630ad05b488..abc4f3dcd5c3d 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShard.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShard.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.index.shard;
 
-import com.carrotsearch.hppc.ObjectLongMap;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.index.CheckIndex;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.Term;
@@ -48,30 +49,37 @@
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.UsageTrackingQueryCachingPolicy;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.util.SetOnce;
+import org.apache.lucene.store.BufferedChecksumIndexInput;
+import org.apache.lucene.store.ChecksumIndexInput;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.util.ThreadInterruptedException;
-import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequest;
 import org.opensearch.action.admin.indices.upgrade.post.UpgradeRequest;
+import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.replication.PendingReplicationActions;
 import org.opensearch.action.support.replication.ReplicationResponse;
+import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.io.stream.BytesStreamOutput;
@@ -82,21 +90,29 @@
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.AsyncIOProcessor;
+import org.opensearch.common.util.concurrent.BufferedAsyncIOProcessor;
 import org.opensearch.common.util.concurrent.RunOnce;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.gateway.WriteStateException;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.ReplicationStats;
+import org.opensearch.index.SegmentReplicationShardStats;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.cache.IndexCache;
 import org.opensearch.index.cache.bitset.ShardBitsetFilterCache;
@@ -109,6 +125,8 @@
 import org.opensearch.index.engine.EngineConfigFactory;
 import org.opensearch.index.engine.EngineException;
 import org.opensearch.index.engine.EngineFactory;
+import org.opensearch.index.engine.InternalEngine;
+import org.opensearch.index.engine.NRTReplicationEngine;
 import org.opensearch.index.engine.ReadOnlyEngine;
 import org.opensearch.index.engine.RefreshFailedEngineException;
 import org.opensearch.index.engine.SafeCommitInfo;
@@ -131,6 +149,8 @@
 import org.opensearch.index.merge.MergeStats;
 import org.opensearch.index.recovery.RecoveryStats;
 import org.opensearch.index.refresh.RefreshStats;
+import org.opensearch.index.remote.RemoteSegmentStats;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.search.stats.SearchStats;
 import org.opensearch.index.search.stats.ShardSearchStats;
 import org.opensearch.index.seqno.ReplicationTracker;
@@ -142,34 +162,46 @@
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.PrimaryReplicaSyncer.ResyncTask;
 import org.opensearch.index.similarity.SimilarityService;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.Store.MetadataSnapshot;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.store.StoreStats;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.index.translog.RemoteBlobStoreInternalTranslogFactory;
+import org.opensearch.index.translog.RemoteFsTranslog;
+import org.opensearch.index.translog.RemoteTranslogStats;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.index.warmer.ShardIndexWarmerService;
 import org.opensearch.index.warmer.WarmerStats;
 import org.opensearch.indices.IndexingMemoryController;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryFailedException;
+import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.suggest.completion.CompletionStats;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.nio.channels.ClosedByInterruptException;
+import java.nio.channels.FileChannel;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -189,6 +221,7 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.LongSupplier;
@@ -197,8 +230,17 @@
 import java.util.stream.StreamSupport;
 
 import static org.opensearch.index.seqno.RetentionLeaseActions.RETAIN_ALL;
+import static org.opensearch.index.seqno.SequenceNumbers.LOCAL_CHECKPOINT_KEY;
+import static org.opensearch.index.seqno.SequenceNumbers.MAX_SEQ_NO;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
+import static org.opensearch.index.translog.Translog.Durability;
+import static org.opensearch.index.translog.Translog.TRANSLOG_UUID_KEY;
 
+/**
+ * An OpenSearch index shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShard extends AbstractIndexShardComponent implements IndicesClusterStateService.Shard {
 
     private final ThreadPool threadPool;
@@ -229,6 +271,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
     private final GlobalCheckpointListeners globalCheckpointListeners;
     private final PendingReplicationActions pendingReplicationActions;
     private final ReplicationTracker replicationTracker;
+    private final SegmentReplicationCheckpointPublisher checkpointPublisher;
 
     protected volatile ShardRouting shardRouting;
     protected volatile IndexShardState state;
@@ -294,6 +337,14 @@ Runnable getGlobalCheckpointSyncer() {
     private final RefreshPendingLocationListener refreshPendingLocationListener;
     private volatile boolean useRetentionLeasesInPeerRecovery;
 
+    private final Store remoteStore;
+    private final BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier;
+    private final boolean isTimeSeriesIndex;
+    private final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    private final List<ReferenceManager.RefreshListener> internalRefreshListener = new ArrayList<>();
+    private final RemoteSegmentStoreDirectoryFactory remoteSegmentStoreDirectoryFactory;
+
     public IndexShard(
         final ShardRouting shardRouting,
         final IndexSettings indexSettings,
@@ -314,13 +365,23 @@ public IndexShard(
         final List<IndexingOperationListener> listeners,
         final Runnable globalCheckpointSyncer,
         final RetentionLeaseSyncer retentionLeaseSyncer,
-        final CircuitBreakerService circuitBreakerService
+        final CircuitBreakerService circuitBreakerService,
+        final BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier,
+        @Nullable final SegmentReplicationCheckpointPublisher checkpointPublisher,
+        @Nullable final Store remoteStore,
+        final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory,
+        final Supplier<TimeValue> clusterRemoteTranslogBufferIntervalSupplier,
+        final String nodeId,
+        // Wiring a directory factory here breaks some intended abstractions, but this remote directory
+        // factory is used not as a Lucene directory but instead to copy files from a remote store when
+        // restoring a shallow snapshot.
+        @Nullable final RemoteSegmentStoreDirectoryFactory remoteSegmentStoreDirectoryFactory
     ) throws IOException {
         super(shardRouting.shardId(), indexSettings);
         assert shardRouting.initializing();
         this.shardRouting = shardRouting;
         final Settings settings = indexSettings.getSettings();
-        this.codecService = new CodecService(mapperService, logger);
+        this.codecService = new CodecService(mapperService, indexSettings, logger);
         this.warmer = warmer;
         this.similarityService = similarityService;
         Objects.requireNonNull(store, "Store must be provided to the index shard");
@@ -330,7 +391,13 @@ public IndexShard(
         this.indexSortSupplier = indexSortSupplier;
         this.indexEventListener = indexEventListener;
         this.threadPool = threadPool;
-        this.translogSyncProcessor = createTranslogSyncProcessor(logger, threadPool.getThreadContext(), this::getEngine);
+        this.translogSyncProcessor = createTranslogSyncProcessor(
+            logger,
+            threadPool,
+            this::getEngine,
+            indexSettings.isRemoteTranslogStoreEnabled(),
+            () -> getRemoteTranslogUploadBufferInterval(clusterRemoteTranslogBufferIntervalSupplier)
+        );
         this.mapperService = mapperService;
         this.indexCache = indexCache;
         this.internalIndexingStats = new InternalIndexingStats();
@@ -354,7 +421,7 @@ public IndexShard(
         logger.debug("state: [CREATED]");
 
         this.checkIndexOnStartup = indexSettings.getValue(IndexSettings.INDEX_CHECK_ON_STARTUP);
-        this.translogConfig = new TranslogConfig(shardId, shardPath().resolveTranslog(), indexSettings, bigArrays);
+        this.translogConfig = new TranslogConfig(shardId, shardPath().resolveTranslog(), indexSettings, bigArrays, nodeId);
         final String aId = shardRouting.allocationId().getId();
         final long primaryTerm = indexSettings.getIndexMetadata().primaryTerm(shardId.id());
         this.pendingPrimaryTerm = primaryTerm;
@@ -397,6 +464,14 @@ public boolean shouldCache(Query query) {
         persistMetadata(path, indexSettings, shardRouting, null, logger);
         this.useRetentionLeasesInPeerRecovery = replicationTracker.hasAllPeerRecoveryRetentionLeases();
         this.refreshPendingLocationListener = new RefreshPendingLocationListener();
+        this.checkpointPublisher = checkpointPublisher;
+        this.remoteStore = remoteStore;
+        this.translogFactorySupplier = translogFactorySupplier;
+        this.isTimeSeriesIndex = (mapperService == null || mapperService.documentMapper() == null)
+            ? false
+            : mapperService.documentMapper().mappers().containsTimeStampField();
+        this.remoteStoreStatsTrackerFactory = remoteStoreStatsTrackerFactory;
+        this.remoteSegmentStoreDirectoryFactory = remoteSegmentStoreDirectoryFactory;
     }
 
     public ThreadPool getThreadPool() {
@@ -407,6 +482,10 @@ public Store store() {
         return this.store;
     }
 
+    public Store remoteStore() {
+        return this.remoteStore;
+    }
+
     /**
      * Return the sort order of this index, or null if the index has no sort.
      */
@@ -446,6 +525,13 @@ public boolean isSystem() {
         return indexSettings.getIndexMetadata().isSystem();
     }
 
+    /**
+     * Returns the name of the default codec in codecService
+     */
+    public String getDefaultCodecName() {
+        return codecService.codec(CodecService.DEFAULT_CODEC).getName();
+    }
+
     /**
      * USE THIS METHOD WITH CARE!
      * Returns the primary term the index shard is supposed to be on. In case of primary promotion or when a replica learns about
@@ -474,6 +560,15 @@ public QueryCachingPolicy getQueryCachingPolicy() {
         return cachingPolicy;
     }
 
+    /** Only used for testing **/
+    protected RemoteStoreStatsTrackerFactory getRemoteStoreStatsTrackerFactory() {
+        return remoteStoreStatsTrackerFactory;
+    }
+
+    public String getNodeId() {
+        return translogConfig.getNodeId();
+    }
+
     @Override
     public void updateShardState(
         final ShardRouting newRouting,
@@ -508,7 +603,7 @@ public void updateShardState(
             }
 
             if (newRouting.primary()) {
-                replicationTracker.updateFromMaster(applyingClusterStateVersion, inSyncAllocationIds, routingTable);
+                replicationTracker.updateFromClusterManager(applyingClusterStateVersion, inSyncAllocationIds, routingTable);
             }
 
             if (state == IndexShardState.POST_RECOVERY && newRouting.active()) {
@@ -516,9 +611,15 @@ public void updateShardState(
                 assert currentRouting.isRelocationTarget() == false
                     || currentRouting.primary() == false
                     || replicationTracker.isPrimaryMode()
-                    : "a primary relocation is completed by the master, but primary mode is not active " + currentRouting;
+                    : "a primary relocation is completed by the cluster-managerr, but primary mode is not active " + currentRouting;
 
                 changeState(IndexShardState.STARTED, "global state is [" + newRouting.state() + "]");
+
+                // Flush here after relocation of primary, so that replica get all changes from new primary rather than waiting for more
+                // docs to get indexed.
+                if (indexSettings.isSegRepEnabled()) {
+                    flush(new FlushRequest().waitIfOngoing(true).force(true));
+                }
             } else if (currentRouting.primary()
                 && currentRouting.relocating()
                 && replicationTracker.isRelocated()
@@ -539,7 +640,7 @@ public void updateShardState(
             if (newRouting.primary()) {
                 if (newPrimaryTerm == pendingPrimaryTerm) {
                     if (currentRouting.initializing() && currentRouting.isRelocationTarget() == false && newRouting.active()) {
-                        // the master started a recovering primary, activate primary mode.
+                        // the cluster-manager started a recovering primary, activate primary mode.
                         replicationTracker.activatePrimaryMode(getLocalCheckpoint());
                         ensurePeerRecoveryRetentionLeasesExist();
                     }
@@ -549,10 +650,10 @@ public void updateShardState(
                      * in one state causing it's term to be incremented. Note that if both current shard state and new
                      * shard state are initializing, we could replace the current shard and reinitialize it. It is however
                      * possible that this shard is being started. This can happen if:
-                     * 1) Shard is post recovery and sends shard started to the master
+                     * 1) Shard is post recovery and sends shard started to the cluster-manager
                      * 2) Node gets disconnected and rejoins
-                     * 3) Master assigns the shard back to the node
-                     * 4) Master processes the shard started and starts the shard
+                     * 3) Cluster-manager assigns the shard back to the node
+                     * 4) Cluster-manager processes the shard started and starts the shard
                      * 5) The node process the cluster state where the shard is both started and primary term is incremented.
                      *
                      * We could fail the shard in that case, but this will cause it to be removed from the insync allocations list
@@ -596,7 +697,23 @@ public void updateShardState(
                             + newRouting;
                         assert getOperationPrimaryTerm() == newPrimaryTerm;
                         try {
+                            if (indexSettings.isSegRepEnabled()) {
+                                // this Shard's engine was read only, we need to update its engine before restoring local history from xlog.
+                                assert newRouting.primary() && currentRouting.primary() == false;
+                                resetEngineToGlobalCheckpoint();
+                                // It is possible an engine can open with a SegmentInfos on a higher gen but the reader does not refresh to
+                                // trigger our refresh listener.
+                                // Force update the checkpoint post engine reset.
+                                updateReplicationCheckpoint();
+                            }
+
                             replicationTracker.activatePrimaryMode(getLocalCheckpoint());
+                            if (indexSettings.isSegRepEnabled()) {
+                                // force publish a checkpoint once in primary mode so that replicas not caught up to previous primary
+                                // are brought up to date.
+                                checkpointPublisher.publish(this, getLatestReplicationCheckpoint());
+                            }
+
                             ensurePeerRecoveryRetentionLeasesExist();
                             /*
                              * If this shard was serving as a replica shard when another shard was promoted to primary then
@@ -652,7 +769,7 @@ public void onFailure(Exception e) {
             this.shardRouting = newRouting;
 
             assert this.shardRouting.primary() == false || this.shardRouting.started() == false || // note that we use started and not
-                                                                                                   // active to avoid relocating shards
+            // active to avoid relocating shards
                 this.indexShardOperationPermits.isBlocked() || // if permits are blocked, we are still transitioning
                 this.replicationTracker.isPrimaryMode() : "a started primary with non-pending operation term must be in primary mode "
                     + this.shardRouting;
@@ -705,23 +822,45 @@ public IndexShardState markAsRecovering(String reason, RecoveryState recoverySta
     private final AtomicBoolean primaryReplicaResyncInProgress = new AtomicBoolean();
 
     /**
-     * Completes the relocation. Operations are blocked and current operations are drained before changing state to relocated. The provided
-     * {@link Runnable} is executed after all operations are successfully blocked.
+     * Completes the relocation. Operations are blocked and current operations are drained before changing state to
+     * relocated. After all operations are successfully blocked, performSegRep is executed followed by target relocation
+     * handoff.
      *
-     * @param consumer a {@link Runnable} that is executed after operations are blocked
+     * @param performSegRep a {@link Runnable} that is executed after operations are blocked
+     * @param consumer a {@link Runnable} that is executed after performSegRep
      * @throws IllegalIndexShardStateException if the shard is not relocating due to concurrent cancellation
      * @throws IllegalStateException           if the relocation target is no longer part of the replication group
      * @throws InterruptedException            if blocking operations is interrupted
      */
-    public void relocated(final String targetAllocationId, final Consumer<ReplicationTracker.PrimaryContext> consumer)
-        throws IllegalIndexShardStateException, IllegalStateException, InterruptedException {
+    public void relocated(
+        final String targetAllocationId,
+        final Consumer<ReplicationTracker.PrimaryContext> consumer,
+        final Runnable performSegRep
+    ) throws IllegalIndexShardStateException, IllegalStateException, InterruptedException {
         assert shardRouting.primary() : "only primaries can be marked as relocated: " + shardRouting;
         try (Releasable forceRefreshes = refreshListeners.forceRefreshes()) {
             indexShardOperationPermits.blockOperations(30, TimeUnit.MINUTES, () -> {
                 forceRefreshes.close();
+
+                boolean syncTranslog = isRemoteTranslogEnabled() && Durability.ASYNC == indexSettings.getTranslogDurability();
+                // Since all the index permits are acquired at this point, the translog buffer will not change.
+                // It is safe to perform sync of translogs now as this will ensure for remote-backed indexes, the
+                // translogs has been uploaded to the remote store.
+                if (syncTranslog) {
+                    maybeSync();
+                }
+
+                // Ensures all in-flight remote store operations drain, before we perform the handoff.
+                internalRefreshListener.stream()
+                    .filter(refreshListener -> refreshListener instanceof Closeable)
+                    .map(refreshListener -> (Closeable) refreshListener)
+                    .close();
+
                 // no shard operation permits are being held here, move state from started to relocated
                 assert indexShardOperationPermits.getActiveOperationsCount() == OPERATIONS_BLOCKED
                     : "in-flight operations in progress while moving shard state to relocated";
+
+                performSegRep.run();
                 /*
                  * We should not invoke the runnable under the mutex as the expected implementation is to handoff the primary context via a
                  * network operation. Doing this under the mutex can implicitly block the cluster state update thread on network operations.
@@ -732,7 +871,8 @@ public void relocated(final String targetAllocationId, final Consumer<Replicatio
                     consumer.accept(primaryContext);
                     synchronized (mutex) {
                         verifyRelocatingState();
-                        replicationTracker.completeRelocationHandoff(); // make changes to primaryMode and relocated flag only under mutex
+                        replicationTracker.completeRelocationHandoff(); // make changes to primaryMode and relocated flag only under
+                        // mutex
                     }
                 } catch (final Exception e) {
                     try {
@@ -752,12 +892,22 @@ public void relocated(final String targetAllocationId, final Consumer<Replicatio
         }
     }
 
+    private void maybeSync() {
+        try {
+            if (isSyncNeeded()) {
+                sync();
+            }
+        } catch (IOException e) {
+            logger.warn("failed to sync translog", e);
+        }
+    }
+
     private void verifyRelocatingState() {
         if (state != IndexShardState.STARTED) {
             throw new IndexShardNotStartedException(shardId, state);
         }
         /*
-         * If the master cancelled recovery, the target will be removed and the recovery will be cancelled. However, it is still possible
+         * If the cluster-manager cancelled recovery, the target will be removed and the recovery will be cancelled. However, it is still possible
          * that we concurrently end up here and therefore have to protect that we do not mark the shard as relocated when its shard routing
          * says otherwise.
          */
@@ -817,11 +967,13 @@ public Engine.IndexResult applyIndexOperationOnPrimary(
             autoGeneratedTimestamp,
             isRetry,
             Engine.Operation.Origin.PRIMARY,
-            sourceToParse
+            sourceToParse,
+            null
         );
     }
 
     public Engine.IndexResult applyIndexOperationOnReplica(
+        String id,
         long seqNo,
         long opPrimaryTerm,
         long version,
@@ -840,7 +992,8 @@ public Engine.IndexResult applyIndexOperationOnReplica(
             autoGeneratedTimeStamp,
             isRetry,
             Engine.Operation.Origin.REPLICA,
-            sourceToParse
+            sourceToParse,
+            id
         );
     }
 
@@ -855,8 +1008,29 @@ private Engine.IndexResult applyIndexOperation(
         long autoGeneratedTimeStamp,
         boolean isRetry,
         Engine.Operation.Origin origin,
-        SourceToParse sourceToParse
+        SourceToParse sourceToParse,
+        String id
     ) throws IOException {
+
+        // For Segment Replication enabled replica shards we can be skip parsing the documents as we directly copy segments from primary
+        // shard.
+        if (indexSettings.isSegRepEnabled() && routingEntry().primary() == false) {
+            Engine.Index index = new Engine.Index(
+                new Term(IdFieldMapper.NAME, Uid.encodeId(id)),
+                new ParsedDocument(null, null, id, null, null, sourceToParse.source(), sourceToParse.getMediaType(), null),
+                seqNo,
+                opPrimaryTerm,
+                version,
+                null,
+                Engine.Operation.Origin.REPLICA,
+                System.nanoTime(),
+                autoGeneratedTimeStamp,
+                isRetry,
+                UNASSIGNED_SEQ_NO,
+                0
+            );
+            return getEngine().index(index);
+        }
         assert opPrimaryTerm <= getOperationPrimaryTerm() : "op term [ "
             + opPrimaryTerm
             + " ] > shard term ["
@@ -1039,6 +1213,21 @@ public Engine.DeleteResult applyDeleteOperationOnPrimary(
     }
 
     public Engine.DeleteResult applyDeleteOperationOnReplica(long seqNo, long opPrimaryTerm, long version, String id) throws IOException {
+        if (indexSettings.isSegRepEnabled()) {
+            final Engine.Delete delete = new Engine.Delete(
+                id,
+                new Term(IdFieldMapper.NAME, Uid.encodeId(id)),
+                seqNo,
+                opPrimaryTerm,
+                version,
+                null,
+                Engine.Operation.Origin.REPLICA,
+                System.nanoTime(),
+                UNASSIGNED_SEQ_NO,
+                0
+            );
+            return getEngine().delete(delete);
+        }
         return applyDeleteOperation(
             getEngine(),
             seqNo,
@@ -1210,12 +1399,23 @@ public MergeStats mergeStats() {
         if (engine == null) {
             return new MergeStats();
         }
-        return engine.getMergeStats();
+        final MergeStats mergeStats = engine.getMergeStats();
+        mergeStats.addUnreferencedFileCleanUpStats(engine.unreferencedFileCleanUpsPerformed());
+        return mergeStats;
     }
 
     public SegmentsStats segmentStats(boolean includeSegmentFileSizes, boolean includeUnloadedSegments) {
         SegmentsStats segmentsStats = getEngine().segmentsStats(includeSegmentFileSizes, includeUnloadedSegments);
         segmentsStats.addBitsetMemoryInBytes(shardBitsetFilterCache.getMemorySizeInBytes());
+        // Populate remote_store stats only if the index is remote store backed
+        if (indexSettings.isRemoteStoreEnabled()) {
+            segmentsStats.addRemoteSegmentStats(
+                new RemoteSegmentStats(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId).stats())
+            );
+        }
+        if (indexSettings.isSegRepEnabled()) {
+            segmentsStats.addReplicationStats(getReplicationStats());
+        }
         return segmentsStats;
     }
 
@@ -1228,7 +1428,15 @@ public FieldDataStats fieldDataStats(String... fields) {
     }
 
     public TranslogStats translogStats() {
-        return getEngine().getTranslogStats();
+        TranslogStats translogStats = getEngine().getTranslogStats();
+        // Populate remote_store stats only if the index is remote store backed
+        if (indexSettings.isRemoteStoreEnabled()) {
+            translogStats.addRemoteTranslogStats(
+                new RemoteTranslogStats(remoteStoreStatsTrackerFactory.getRemoteTranslogTransferTracker(shardId).stats())
+            );
+        }
+
+        return translogStats;
     }
 
     public CompletionStats completionStats(String... fields) {
@@ -1343,6 +1551,50 @@ public GatedCloseable<IndexCommit> acquireLastIndexCommit(boolean flushFirst) th
         }
     }
 
+    public GatedCloseable<IndexCommit> acquireLastIndexCommitAndRefresh(boolean flushFirst) throws EngineException {
+        GatedCloseable<IndexCommit> indexCommit = acquireLastIndexCommit(flushFirst);
+        getEngine().refresh("Snapshot for Remote Store based Shard");
+        return indexCommit;
+    }
+
+    /**
+     *
+     * @param snapshotId Snapshot UUID.
+     * @param primaryTerm current primary term.
+     * @param generation Snapshot Commit Generation.
+     * @throws IOException if there is some failure in acquiring lock in remote store.
+     */
+    public void acquireLockOnCommitData(String snapshotId, long primaryTerm, long generation) throws IOException {
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory = getRemoteDirectory();
+        remoteSegmentStoreDirectory.acquireLock(primaryTerm, generation, snapshotId);
+    }
+
+    /**
+     *
+     * @param snapshotId Snapshot UUID.
+     * @param primaryTerm current primary term.
+     * @param generation Snapshot Commit Generation.
+     * @throws IOException if there is some failure in releasing lock in remote store.
+     */
+    public void releaseLockOnCommitData(String snapshotId, long primaryTerm, long generation) throws IOException {
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory = getRemoteDirectory();
+        remoteSegmentStoreDirectory.releaseLock(primaryTerm, generation, snapshotId);
+    }
+
+    public Optional<NRTReplicationEngine> getReplicationEngine() {
+        if (getEngine() instanceof NRTReplicationEngine) {
+            return Optional.of((NRTReplicationEngine) getEngine());
+        } else {
+            return Optional.empty();
+        }
+    }
+
+    public void finalizeReplication(SegmentInfos infos) throws IOException {
+        if (getReplicationEngine().isPresent()) {
+            getReplicationEngine().get().updateSegments(infos);
+        }
+    }
+
     /**
      * Snapshots the most recent safe index commit from the currently running engine.
      * All index files referenced by this index commit won't be freed until the commit/snapshot is closed.
@@ -1357,6 +1609,138 @@ public GatedCloseable<IndexCommit> acquireSafeIndexCommit() throws EngineExcepti
         }
     }
 
+    /**
+     * Compute and return the latest ReplicationCheckpoint for a particular shard.
+     * @return EMPTY checkpoint before the engine is opened and null for non-segrep enabled indices
+     */
+    public ReplicationCheckpoint getLatestReplicationCheckpoint() {
+        return replicationTracker.getLatestReplicationCheckpoint();
+    }
+
+    /**
+     * Compute and return the latest ReplicationCheckpoint for a shard and a GatedCloseable containing the corresponding SegmentInfos.
+     * The segments referenced by the SegmentInfos will remain on disk until the GatedCloseable is closed.
+     *
+     * Primary shards compute the seqNo used in the replication checkpoint from the fetched SegmentInfos.
+     * Replica shards compute the seqNo from its latest processed checkpoint, which only increases when refreshing on new segments.
+     *
+     * @return A {@link Tuple} containing SegmentInfos wrapped in a {@link GatedCloseable} and the {@link ReplicationCheckpoint} computed from the infos.
+     *
+     */
+    public Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> getLatestSegmentInfosAndCheckpoint() {
+        assert indexSettings.isSegRepEnabled();
+
+        Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> nullSegmentInfosEmptyCheckpoint = new Tuple<>(
+            new GatedCloseable<>(null, () -> {}),
+            getLatestReplicationCheckpoint()
+        );
+
+        if (getEngineOrNull() == null) {
+            return nullSegmentInfosEmptyCheckpoint;
+        }
+        // do not close the snapshot - caller will close it.
+        GatedCloseable<SegmentInfos> snapshot = null;
+        try {
+            snapshot = getSegmentInfosSnapshot();
+            if (snapshot.get() != null) {
+                SegmentInfos segmentInfos = snapshot.get();
+                final Map<String, StoreFileMetadata> metadataMap = store.getSegmentMetadataMap(segmentInfos);
+                return new Tuple<>(
+                    snapshot,
+                    new ReplicationCheckpoint(
+                        this.shardId,
+                        getOperationPrimaryTerm(),
+                        segmentInfos.getGeneration(),
+                        segmentInfos.getVersion(),
+                        metadataMap.values().stream().mapToLong(StoreFileMetadata::length).sum(),
+                        getEngine().config().getCodec().getName(),
+                        metadataMap
+                    )
+                );
+            }
+        } catch (IOException | AlreadyClosedException e) {
+            logger.error("Error Fetching SegmentInfos and latest checkpoint", e);
+            if (snapshot != null) {
+                try {
+                    snapshot.close();
+                } catch (IOException ex) {
+                    throw new OpenSearchException("Error Closing SegmentInfos Snapshot", e);
+                }
+            }
+        }
+        return nullSegmentInfosEmptyCheckpoint;
+    }
+
+    /**
+     * Checks if this target shard should start a round of segment replication.
+     * @return - True if the shard is able to perform segment replication.
+     */
+    public boolean isSegmentReplicationAllowed() {
+        if (indexSettings.isSegRepEnabled() == false) {
+            logger.trace("Attempting to perform segment replication when it is not enabled on the index");
+            return false;
+        }
+        if (getReplicationTracker().isPrimaryMode()) {
+            logger.trace("Shard is in primary mode and cannot perform segment replication as a replica.");
+            return false;
+        }
+        if (this.routingEntry().primary()) {
+            logger.trace("Shard routing is marked primary thus cannot perform segment replication as replica");
+            return false;
+        }
+        if (state().equals(IndexShardState.STARTED) == false
+            && (state() == IndexShardState.POST_RECOVERY && shardRouting.state() == ShardRoutingState.INITIALIZING) == false) {
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "Shard is not started or recovering {} {} and cannot perform segment replication as a replica",
+                    state(),
+                    shardRouting.state()
+                )
+            );
+            return false;
+        }
+        if (getReplicationEngine().isEmpty()) {
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "Shard does not have the correct engine type to perform segment replication {}.",
+                    getEngine().getClass()
+                )
+            );
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Checks if checkpoint should be processed
+     *
+     * @param requestCheckpoint       received checkpoint that is checked for processing
+     * @return true if checkpoint should be processed
+     */
+    public final boolean shouldProcessCheckpoint(ReplicationCheckpoint requestCheckpoint) {
+        if (isSegmentReplicationAllowed() == false) {
+            return false;
+        }
+        ReplicationCheckpoint localCheckpoint = getLatestReplicationCheckpoint();
+        if (localCheckpoint.isAheadOf(requestCheckpoint)) {
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "Ignoring new replication checkpoint - Shard is already on checkpoint {} that is ahead of {}",
+                    localCheckpoint,
+                    requestCheckpoint
+                )
+            );
+            return false;
+        }
+        if (localCheckpoint.equals(requestCheckpoint)) {
+            logger.trace(
+                () -> new ParameterizedMessage("Ignoring new replication checkpoint - Shard is already on checkpoint {}", requestCheckpoint)
+            );
+            return false;
+        }
+        return true;
+    }
+
     /**
      * gets a {@link Store.MetadataSnapshot} for the current directory. This method is safe to call in all lifecycle of the index shard,
      * without having to worry about the current state of the engine and concurrent flushes.
@@ -1393,6 +1777,19 @@ public Store.MetadataSnapshot snapshotStoreMetadata() throws IOException {
         }
     }
 
+    /**
+     * Fetch a map of StoreFileMetadata for each segment from the latest SegmentInfos.
+     * This is used to compute diffs for segment replication.
+     *
+     * @return - Map of Segment Filename to its {@link StoreFileMetadata}
+     * @throws IOException - When there is an error loading metadata from the store.
+     */
+    public Map<String, StoreFileMetadata> getSegmentMetadataMap() throws IOException {
+        try (final GatedCloseable<SegmentInfos> snapshot = getSegmentInfosSnapshot()) {
+            return store.getSegmentMetadataMap(snapshot.get());
+        }
+    }
+
     /**
      * Fails the shard and marks the shard store as corrupted if
      * <code>e</code> is caused by index corruption
@@ -1498,6 +1895,29 @@ static Engine.Searcher wrapSearcher(
         }
     }
 
+    public void onCheckpointPublished(ReplicationCheckpoint checkpoint) {
+        replicationTracker.startReplicationLagTimers(checkpoint);
+    }
+
+    /**
+     * Used with segment replication during relocation handoff, this method updates current read only engine to global
+     * checkpoint followed by changing to writeable engine
+     *
+     * @throws IOException if communication failed
+     * @throws InterruptedException if calling thread is interrupted
+     * @throws TimeoutException if timed out waiting for in-flight operations to finish
+     *
+     * @opensearch.internal
+     */
+    public void resetToWriteableEngine() throws IOException, InterruptedException, TimeoutException {
+        indexShardOperationPermits.blockOperations(30, TimeUnit.MINUTES, () -> { resetEngineToGlobalCheckpoint(); });
+    }
+
+    /**
+     * Wrapper for a non-closing reader
+     *
+     * @opensearch.internal
+     */
     private static final class NonClosingReaderWrapper extends FilterDirectoryReader {
 
         private NonClosingReaderWrapper(DirectoryReader in) throws IOException {
@@ -1526,7 +1946,7 @@ public CacheHelper getReaderCacheHelper() {
 
     }
 
-    public void close(String reason, boolean flushEngine) throws IOException {
+    public void close(String reason, boolean flushEngine, boolean deleted) throws IOException {
         synchronized (engineMutex) {
             try {
                 synchronized (mutex) {
@@ -1542,12 +1962,32 @@ public void close(String reason, boolean flushEngine) throws IOException {
                     // playing safe here and close the engine even if the above succeeds - close can be called multiple times
                     // Also closing refreshListeners to prevent us from accumulating any more listeners
                     IOUtils.close(engine, globalCheckpointListeners, refreshListeners, pendingReplicationActions);
+
+                    if (deleted && engine != null && isPrimaryMode() && isRemoteTranslogEnabled()) {
+                        // Translog Clean up
+                        if (engine instanceof InternalEngine) {
+                            ((InternalEngine) engine).translogManager().onDelete();
+                        }
+                    }
+
                     indexShardOperationPermits.close();
                 }
             }
         }
     }
 
+    /*
+    ToDo : Fix this https://github.com/opensearch-project/OpenSearch/issues/8003
+     */
+    private RemoteSegmentStoreDirectory getRemoteDirectory() {
+        assert indexSettings.isRemoteStoreEnabled();
+        assert remoteStore.directory() instanceof FilterDirectory : "Store.directory is not an instance of FilterDirectory";
+        FilterDirectory remoteStoreDirectory = (FilterDirectory) remoteStore.directory();
+        FilterDirectory byteSizeCachingStoreDirectory = (FilterDirectory) remoteStoreDirectory.getDelegate();
+        final Directory remoteDirectory = byteSizeCachingStoreDirectory.getDelegate();
+        return ((RemoteSegmentStoreDirectory) remoteDirectory);
+    }
+
     public void preRecovery() {
         final IndexShardState currentState = this.state; // single volatile read
         if (currentState == IndexShardState.CLOSED) {
@@ -1594,17 +2034,12 @@ public void prepareForIndexRecovery() {
      * @return a sequence number that an operation-based peer recovery can start with.
      * This is the first operation after the local checkpoint of the safe commit if exists.
      */
-    public long recoverLocallyUpToGlobalCheckpoint() {
-        assert Thread.holdsLock(mutex) == false : "recover locally under mutex";
-        if (state != IndexShardState.RECOVERING) {
-            throw new IndexShardNotRecoveringException(shardId, state);
-        }
-        recoveryState.validateCurrentStage(RecoveryState.Stage.INDEX);
-        assert routingEntry().recoverySource().getType() == RecoverySource.Type.PEER : "not a peer recovery [" + routingEntry() + "]";
+    private long recoverLocallyUpToGlobalCheckpoint() {
+        validateLocalRecoveryState();
         final Optional<SequenceNumbers.CommitInfo> safeCommit;
         final long globalCheckpoint;
         try {
-            final String translogUUID = store.readLastCommittedSegmentsInfo().getUserData().get(Translog.TRANSLOG_UUID_KEY);
+            final String translogUUID = store.readLastCommittedSegmentsInfo().getUserData().get(TRANSLOG_UUID_KEY);
             globalCheckpoint = Translog.readGlobalCheckpoint(translogConfig.getTranslogPath(), translogUUID);
             safeCommit = store.findSafeIndexCommit(globalCheckpoint);
         } catch (org.apache.lucene.index.IndexNotFoundException e) {
@@ -1682,6 +2117,54 @@ public long recoverLocallyUpToGlobalCheckpoint() {
         }
     }
 
+    public long recoverLocallyAndFetchStartSeqNo(boolean localTranslog) {
+        if (localTranslog) {
+            return recoverLocallyUpToGlobalCheckpoint();
+        } else {
+            return recoverLocallyUptoLastCommit();
+        }
+    }
+
+    /**
+     * The method figures out the sequence number basis the last commit.
+     *
+     * @return the starting sequence number from which the recovery should start.
+     */
+    private long recoverLocallyUptoLastCommit() {
+        assert isRemoteTranslogEnabled() : "Remote translog store is not enabled";
+        long seqNo;
+        validateLocalRecoveryState();
+
+        try {
+            seqNo = Long.parseLong(store.readLastCommittedSegmentsInfo().getUserData().get(MAX_SEQ_NO));
+        } catch (org.apache.lucene.index.IndexNotFoundException e) {
+            logger.error("skip local recovery as no index commit found");
+            return UNASSIGNED_SEQ_NO;
+        } catch (Exception e) {
+            logger.error("skip local recovery as failed to find the safe commit", e);
+            return UNASSIGNED_SEQ_NO;
+        }
+
+        try {
+            maybeCheckIndex();
+            recoveryState.setStage(RecoveryState.Stage.TRANSLOG);
+            recoveryState.getTranslog().totalLocal(0);
+        } catch (Exception e) {
+            logger.error("check index failed during fetch seqNo", e);
+            return UNASSIGNED_SEQ_NO;
+        }
+        return seqNo;
+    }
+
+    private void validateLocalRecoveryState() {
+        assert Thread.holdsLock(mutex) == false : "recover locally under mutex";
+        if (state != IndexShardState.RECOVERING) {
+            throw new IndexShardNotRecoveringException(shardId, state);
+        }
+        recoveryState.validateCurrentStage(RecoveryState.Stage.INDEX);
+        assert routingEntry().recoverySource().getType() == RecoverySource.Type.PEER : "not a peer recovery [" + routingEntry() + "]";
+    }
+
     public void trimOperationOfPreviousPrimaryTerms(long aboveSeqNo) {
         getEngine().trimOperationsFromTranslog(getOperationPrimaryTerm(), aboveSeqNo);
     }
@@ -1738,9 +2221,10 @@ private Engine.Result applyTranslogOperation(Engine engine, Translog.Operation o
                         shardId.getIndexName(),
                         index.id(),
                         index.source(),
-                        XContentHelper.xContentType(index.source()),
+                        MediaTypeRegistry.xContentType(index.source()),
                         index.routing()
-                    )
+                    ),
+                    index.id()
                 );
                 break;
             case DELETE:
@@ -1809,7 +2293,7 @@ private void loadGlobalCheckpointToReplicationTracker() throws IOException {
         // we have to set it before we open an engine and recover from the translog because
         // acquiring a snapshot from the translog causes a sync which causes the global checkpoint to be pulled in,
         // and an engine can be forced to close in ctor which also causes the global checkpoint to be pulled in.
-        final String translogUUID = store.readLastCommittedSegmentsInfo().getUserData().get(Translog.TRANSLOG_UUID_KEY);
+        final String translogUUID = store.readLastCommittedSegmentsInfo().getUserData().get(TRANSLOG_UUID_KEY);
         final long globalCheckpoint = Translog.readGlobalCheckpoint(translogConfig.getTranslogPath(), translogUUID);
         replicationTracker.updateGlobalCheckpointOnReplica(globalCheckpoint, "read from translog checkpoint");
     }
@@ -1833,7 +2317,12 @@ public void openEngineAndRecoverFromTranslog() throws IOException {
                 translogRecoveryStats::incrementRecoveredOperations
             );
         };
-        loadGlobalCheckpointToReplicationTracker();
+
+        // Do not load the global checkpoint if this is a remote snapshot index
+        if (indexSettings.isRemoteSnapshot() == false) {
+            loadGlobalCheckpointToReplicationTracker();
+        }
+
         innerOpenEngineAndTranslog(replicationTracker);
         getEngine().recoverFromTranslog(translogRecoveryRunner, Long.MAX_VALUE);
     }
@@ -1850,7 +2339,25 @@ public void openEngineAndSkipTranslogRecovery() throws IOException {
         getEngine().skipTranslogRecovery();
     }
 
+    public void openEngineAndSkipTranslogRecoveryFromSnapshot() throws IOException {
+        assert routingEntry().recoverySource().getType() == RecoverySource.Type.SNAPSHOT : "not a snapshot recovery ["
+            + routingEntry()
+            + "]";
+        recoveryState.validateCurrentStage(RecoveryState.Stage.INDEX);
+        maybeCheckIndex();
+        recoveryState.setStage(RecoveryState.Stage.TRANSLOG);
+        recoveryState.validateCurrentStage(RecoveryState.Stage.TRANSLOG);
+        loadGlobalCheckpointToReplicationTracker();
+        innerOpenEngineAndTranslog(replicationTracker, false);
+        getEngine().skipTranslogRecovery();
+    }
+
     private void innerOpenEngineAndTranslog(LongSupplier globalCheckpointSupplier) throws IOException {
+        innerOpenEngineAndTranslog(globalCheckpointSupplier, true);
+    }
+
+    private void innerOpenEngineAndTranslog(LongSupplier globalCheckpointSupplier, boolean syncFromRemote) throws IOException {
+        syncFromRemote = syncFromRemote && indexSettings.isRemoteSnapshot() == false;
         assert Thread.holdsLock(mutex) == false : "opening engine under mutex";
         if (state != IndexShardState.RECOVERING) {
             throw new IndexShardNotRecoveringException(shardId, state);
@@ -1869,10 +2376,49 @@ private void innerOpenEngineAndTranslog(LongSupplier globalCheckpointSupplier) t
         synchronized (engineMutex) {
             assert currentEngineReference.get() == null : "engine is running";
             verifyNotClosed();
+            if (indexSettings.isRemoteStoreEnabled()) {
+                // Download missing segments from remote segment store.
+                if (syncFromRemote) {
+                    syncSegmentsFromRemoteSegmentStore(false);
+                }
+                if (shardRouting.primary()) {
+                    if (syncFromRemote) {
+                        syncRemoteTranslogAndUpdateGlobalCheckpoint();
+                    } else {
+                        // we will enter this block when we do not want to recover from remote translog.
+                        // currently only during snapshot restore, we are coming into this block.
+                        // here, as while initiliazing remote translog we cannot skip downloading translog files,
+                        // so before that step, we are deleting the translog files present in remote store.
+                        deleteTranslogFilesFromRemoteTranslog();
+                    }
+                } else if (syncFromRemote) {
+                    // For replicas, when we download segments from remote segment store, we need to make sure that local
+                    // translog is having the same UUID that is referred by the segments. If they are different, engine open
+                    // fails with TranslogCorruptedException. It is safe to create empty translog for remote store enabled
+                    // indices as replica would only need to read translog in failover scenario and we always fetch data
+                    // from remote translog at the time of failover.
+                    final SegmentInfos lastCommittedSegmentInfos = store().readLastCommittedSegmentsInfo();
+                    final String translogUUID = lastCommittedSegmentInfos.userData.get(TRANSLOG_UUID_KEY);
+                    final long checkpoint = Long.parseLong(lastCommittedSegmentInfos.userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
+                    Translog.createEmptyTranslog(
+                        shardPath().resolveTranslog(),
+                        shardId(),
+                        checkpoint,
+                        getPendingPrimaryTerm(),
+                        translogUUID,
+                        FileChannel::open
+                    );
+                }
+            }
             // we must create a new engine under mutex (see IndexShard#snapshotStoreMetadata).
             final Engine newEngine = engineFactory.newReadWriteEngine(config);
             onNewEngine(newEngine);
             currentEngineReference.set(newEngine);
+
+            if (indexSettings.isSegRepEnabled()) {
+                // set initial replication checkpoints into tracker.
+                updateReplicationCheckpoint();
+            }
             // We set active because we are now writing operations to the engine; this way,
             // we can flush if we go idle after some time and become inactive.
             active.set(true);
@@ -1885,9 +2431,9 @@ private void innerOpenEngineAndTranslog(LongSupplier globalCheckpointSupplier) t
     }
 
     private boolean assertSequenceNumbersInCommit() throws IOException {
-        final Map<String, String> userData = SegmentInfos.readLatestCommit(store.directory()).getUserData();
+        final Map<String, String> userData = fetchUserData();
         assert userData.containsKey(SequenceNumbers.LOCAL_CHECKPOINT_KEY) : "commit point doesn't contains a local checkpoint";
-        assert userData.containsKey(SequenceNumbers.MAX_SEQ_NO) : "commit point doesn't contains a maximum sequence number";
+        assert userData.containsKey(MAX_SEQ_NO) : "commit point doesn't contains a maximum sequence number";
         assert userData.containsKey(Engine.HISTORY_UUID_KEY) : "commit point doesn't contains a history uuid";
         assert userData.get(Engine.HISTORY_UUID_KEY).equals(getHistoryUUID()) : "commit point history uuid ["
             + userData.get(Engine.HISTORY_UUID_KEY)
@@ -1900,6 +2446,14 @@ private boolean assertSequenceNumbersInCommit() throws IOException {
         return true;
     }
 
+    private Map<String, String> fetchUserData() throws IOException {
+        if (indexSettings.isRemoteSnapshot() && indexSettings.getExtendedCompatibilitySnapshotVersion() != null) {
+            return Lucene.readSegmentInfos(store.directory(), indexSettings.getExtendedCompatibilitySnapshotVersion()).getUserData();
+        } else {
+            return SegmentInfos.readLatestCommit(store.directory()).getUserData();
+        }
+    }
+
     private void onNewEngine(Engine newEngine) {
         assert Thread.holdsLock(engineMutex);
         refreshListeners.setCurrentRefreshLocationSupplier(newEngine::getTranslogLastWriteLocation);
@@ -2021,6 +2575,11 @@ private boolean assertPrimaryMode() {
         return true;
     }
 
+    // Returns true if shard routing is primary & replication tracker is in primary mode.
+    public boolean isPrimaryMode() {
+        return shardRouting.primary() && replicationTracker.isPrimaryMode();
+    }
+
     private boolean assertReplicationTarget() {
         assert replicationTracker.isPrimaryMode() == false : "shard " + shardRouting + " in primary mode cannot be a replication target";
         return true;
@@ -2140,6 +2699,28 @@ public void recoverFromStore(ActionListener<Boolean> listener) {
         storeRecovery.recoverFromStore(this, listener);
     }
 
+    public void restoreFromRemoteStore(ActionListener<Boolean> listener) {
+        assert shardRouting.primary() : "recover from store only makes sense if the shard is a primary shard";
+        StoreRecovery storeRecovery = new StoreRecovery(shardId, logger);
+        storeRecovery.recoverFromRemoteStore(this, listener);
+    }
+
+    public void restoreFromSnapshotAndRemoteStore(
+        Repository repository,
+        RemoteSegmentStoreDirectoryFactory remoteSegmentStoreDirectoryFactory,
+        ActionListener<Boolean> listener
+    ) {
+        try {
+            assert shardRouting.primary() : "recover from store only makes sense if the shard is a primary shard";
+            assert recoveryState.getRecoverySource().getType() == RecoverySource.Type.SNAPSHOT : "invalid recovery type: "
+                + recoveryState.getRecoverySource();
+            StoreRecovery storeRecovery = new StoreRecovery(shardId, logger);
+            storeRecovery.recoverFromSnapshotAndRemoteStore(this, repository, remoteSegmentStoreDirectoryFactory, listener);
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
     public void restoreFromRepository(Repository repository, ActionListener<Boolean> listener) {
         try {
             assert shardRouting.primary() : "recover from store only makes sense if the shard is a primary shard";
@@ -2233,13 +2814,25 @@ public Closeable acquireHistoryRetentionLock() {
     /**
      * Creates a new history snapshot for reading operations since
      * the provided starting seqno (inclusive) and ending seqno (inclusive)
-     * The returned snapshot can be retrieved from either Lucene index or translog files.
+     * The returned snapshot is retrieved from a Lucene index.
      */
     public Translog.Snapshot getHistoryOperations(String reason, long startingSeqNo, long endSeqNo, boolean accurateCount)
         throws IOException {
         return getEngine().newChangesSnapshot(reason, startingSeqNo, endSeqNo, true, accurateCount);
     }
 
+    /**
+     * Creates a new history snapshot from the translog file instead of the lucene index
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     *
+     * Use {@link IndexShard#getHistoryOperations(String, long, long, boolean)} instead
+     */
+    @Deprecated
+    public Translog.Snapshot getHistoryOperationsFromTranslogFile(String reason, long startingSeqNo, long endSeqNo) throws IOException {
+        return getEngine().newChangesSnapshotFromTranslogFile(reason, startingSeqNo, endSeqNo, true);
+    }
+
     /**
      * Checks if we have a completed history of operations since the given starting seqno (inclusive).
      * This method should be called after acquiring the retention lock; See {@link #acquireHistoryRetentionLock()}
@@ -2378,6 +2971,43 @@ public void updateGlobalCheckpointForShard(final String allocationId, final long
         replicationTracker.updateGlobalCheckpointForShard(allocationId, globalCheckpoint);
     }
 
+    /**
+     * Update the local knowledge of the visible global checkpoint for the specified allocation ID.
+     *
+     * @param allocationId     the allocation ID to update the global checkpoint for
+     * @param visibleCheckpoint the visible checkpoint
+     */
+    public void updateVisibleCheckpointForShard(final String allocationId, final ReplicationCheckpoint visibleCheckpoint) {
+        // Update target replication checkpoint only when in active primary mode
+        if (this.isPrimaryMode()) {
+            verifyNotClosed();
+            replicationTracker.updateVisibleCheckpointForShard(allocationId, visibleCheckpoint);
+        }
+    }
+
+    /**
+     * Fetch stats on segment replication.
+     * @return {@link Tuple} V1 - TimeValue in ms - mean replication lag for this primary to its entire group,
+     * V2 - Set of {@link SegmentReplicationShardStats} per shard in this primary's replication group.
+     */
+    public Set<SegmentReplicationShardStats> getReplicationStatsForTrackedReplicas() {
+        return replicationTracker.getSegmentReplicationStats();
+    }
+
+    public ReplicationStats getReplicationStats() {
+        if (indexSettings.isSegRepEnabled() && routingEntry().primary()) {
+            final Set<SegmentReplicationShardStats> stats = getReplicationStatsForTrackedReplicas();
+            long maxBytesBehind = stats.stream().mapToLong(SegmentReplicationShardStats::getBytesBehindCount).max().orElse(0L);
+            long totalBytesBehind = stats.stream().mapToLong(SegmentReplicationShardStats::getBytesBehindCount).sum();
+            long maxReplicationLag = stats.stream()
+                .mapToLong(SegmentReplicationShardStats::getCurrentReplicationTimeMillis)
+                .max()
+                .orElse(0L);
+            return new ReplicationStats(maxBytesBehind, totalBytesBehind, maxReplicationLag);
+        }
+        return new ReplicationStats();
+    }
+
     /**
      * Add a global checkpoint listener. If the global checkpoint is equal to or above the global checkpoint the listener is waiting for,
      * then the listener will be notified immediately via an executor (so possibly not on the current thread). If the specified timeout
@@ -2602,6 +3232,19 @@ public long getLocalCheckpoint() {
         return getEngine().getPersistedLocalCheckpoint();
     }
 
+    /**
+     * Fetch the latest checkpoint that has been processed but not necessarily persisted. This should be used only when Segment Replication is enabled.
+     * Also see {@link #getLocalCheckpoint()}.
+     */
+    public long getProcessedLocalCheckpoint() {
+        // Returns checkpoint only if the current engine is an instance of NRTReplicationEngine or InternalEngine
+        return getReplicationEngine().map(NRTReplicationEngine::getProcessedLocalCheckpoint).orElseGet(() -> {
+            final Engine engine = getEngine();
+            assert engine instanceof InternalEngine;
+            return ((InternalEngine) engine).getProcessedLocalCheckpoint();
+        });
+    }
+
     /**
      * Returns the global checkpoint for the shard.
      *
@@ -2623,7 +3266,7 @@ public long getLastSyncedGlobalCheckpoint() {
      *
      * @return a map from allocation ID to the local knowledge of the global checkpoint for that allocation ID
      */
-    public ObjectLongMap<String> getInSyncGlobalCheckpoints() {
+    public Map<String, Long> getInSyncGlobalCheckpoints() {
         assert assertPrimaryMode();
         verifyNotClosed();
         return replicationTracker.getInSyncGlobalCheckpoints();
@@ -2642,9 +3285,9 @@ public void maybeSyncGlobalCheckpoint(final String reason) {
         assert assertPrimaryMode();
         // only sync if there are no operations in flight, or when using async durability
         final SeqNoStats stats = getEngine().getSeqNoStats(replicationTracker.getGlobalCheckpoint());
-        final boolean asyncDurability = indexSettings().getTranslogDurability() == Translog.Durability.ASYNC;
+        final boolean asyncDurability = indexSettings().getTranslogDurability() == Durability.ASYNC;
         if (stats.getMaxSeqNo() == stats.getGlobalCheckpoint() || asyncDurability) {
-            final ObjectLongMap<String> globalCheckpoints = getInSyncGlobalCheckpoints();
+            final Map<String, Long> globalCheckpoints = getInSyncGlobalCheckpoints();
             final long globalCheckpoint = replicationTracker.getGlobalCheckpoint();
             // async durability means that the local checkpoint might lag (as it is only advanced on fsync)
             // periodically ask for the newest local checkpoint by syncing the global checkpoint, so that ultimately the global
@@ -2654,7 +3297,7 @@ public void maybeSyncGlobalCheckpoint(final String reason) {
             final boolean syncNeeded = (asyncDurability
                 && (stats.getGlobalCheckpoint() < stats.getMaxSeqNo() || replicationTracker.pendingInSync()))
                 // check if the persisted global checkpoint
-                || StreamSupport.stream(globalCheckpoints.values().spliterator(), false).anyMatch(v -> v.value < globalCheckpoint);
+                || StreamSupport.stream(globalCheckpoints.values().spliterator(), false).anyMatch(v -> v < globalCheckpoint);
             // only sync if index is not closed and there is a shard lagging the primary
             if (syncNeeded && indexSettings.getIndexMetadata().getState() == IndexMetadata.State.OPEN) {
                 logger.trace("syncing global checkpoint for [{}]", reason);
@@ -2708,9 +3351,11 @@ public void updateGlobalCheckpointOnReplica(final long globalCheckpoint, final S
              * calculations of the global checkpoint. However, we can not assert that we are in the translog stage of recovery here as
              * while the global checkpoint update may have emanated from the primary when we were in that state, we could subsequently move
              * to recovery finalization, or even finished recovery before the update arrives here.
+             * When remote translog is enabled for an index, replication operation is limited to primary term validation and does not
+             * update local checkpoint at replica, so the local checkpoint at replica can be less than globalCheckpoint.
              */
-            assert state() != IndexShardState.POST_RECOVERY && state() != IndexShardState.STARTED
-                : "supposedly in-sync shard copy received a global checkpoint ["
+            assert (state() != IndexShardState.POST_RECOVERY && state() != IndexShardState.STARTED)
+                || indexSettings.isRemoteTranslogStoreEnabled() : "supposedly in-sync shard copy received a global checkpoint ["
                     + globalCheckpoint
                     + "] "
                     + "that is higher than its local checkpoint ["
@@ -2735,7 +3380,7 @@ public void activateWithPrimaryContext(final ReplicationTracker.PrimaryContext p
             + routingEntry()
             + "]";
         assert getLocalCheckpoint() == primaryContext.getCheckpointStates().get(routingEntry().allocationId().getId()).getLocalCheckpoint()
-            || indexSettings().getTranslogDurability() == Translog.Durability.ASYNC : "local checkpoint ["
+            || indexSettings().getTranslogDurability() == Durability.ASYNC : "local checkpoint ["
                 + getLocalCheckpoint()
                 + "] does not match checkpoint from primary context ["
                 + primaryContext
@@ -2866,7 +3511,7 @@ protected Engine getEngineOrNull() {
     public void startRecovery(
         RecoveryState recoveryState,
         PeerRecoveryTargetService recoveryTargetService,
-        PeerRecoveryTargetService.RecoveryListener recoveryListener,
+        RecoveryListener recoveryListener,
         RepositoriesService repositoriesService,
         Consumer<MappingMetadata> mappingUpdateConsumer,
         IndicesService indicesService
@@ -2887,29 +3532,47 @@ public void startRecovery(
         // }
         // }}
         // }
+        logger.debug("startRecovery type={}", recoveryState.getRecoverySource().getType());
         assert recoveryState.getRecoverySource().equals(shardRouting.recoverySource());
         switch (recoveryState.getRecoverySource().getType()) {
             case EMPTY_STORE:
             case EXISTING_STORE:
                 executeRecovery("from store", recoveryState, recoveryListener, this::recoverFromStore);
                 break;
+            case REMOTE_STORE:
+                executeRecovery("from remote store", recoveryState, recoveryListener, l -> restoreFromRemoteStore(l));
+                break;
             case PEER:
                 try {
                     markAsRecovering("from " + recoveryState.getSourceNode(), recoveryState);
                     recoveryTargetService.startRecovery(this, recoveryState.getSourceNode(), recoveryListener);
                 } catch (Exception e) {
                     failShard("corrupted preexisting index", e);
-                    recoveryListener.onRecoveryFailure(recoveryState, new RecoveryFailedException(recoveryState, null, e), true);
+                    recoveryListener.onFailure(recoveryState, new RecoveryFailedException(recoveryState, null, e), true);
                 }
                 break;
             case SNAPSHOT:
-                final String repo = ((SnapshotRecoverySource) recoveryState.getRecoverySource()).snapshot().getRepository();
-                executeRecovery(
-                    "from snapshot",
-                    recoveryState,
-                    recoveryListener,
-                    l -> restoreFromRepository(repositoriesService.repository(repo), l)
-                );
+                final SnapshotRecoverySource recoverySource = (SnapshotRecoverySource) recoveryState.getRecoverySource();
+                if (recoverySource.isSearchableSnapshot()) {
+                    executeRecovery("from snapshot (remote)", recoveryState, recoveryListener, this::recoverFromStore);
+                } else if (recoverySource.remoteStoreIndexShallowCopy()) {
+                    final String repo = recoverySource.snapshot().getRepository();
+                    executeRecovery(
+                        "from snapshot and remote store",
+                        recoveryState,
+                        recoveryListener,
+                        l -> restoreFromSnapshotAndRemoteStore(repositoriesService.repository(repo), remoteSegmentStoreDirectoryFactory, l)
+                    );
+                    // indicesService.indexService(shardRouting.shardId().getIndex()).addMetadataListener();
+                } else {
+                    final String repo = recoverySource.snapshot().getRepository();
+                    executeRecovery(
+                        "from snapshot",
+                        recoveryState,
+                        recoveryListener,
+                        l -> restoreFromRepository(repositoriesService.repository(repo), l)
+                    );
+                }
                 break;
             case LOCAL_SHARDS:
                 final IndexMetadata indexMetadata = indexSettings().getIndexMetadata();
@@ -2974,15 +3637,15 @@ public void startRecovery(
     private void executeRecovery(
         String reason,
         RecoveryState recoveryState,
-        PeerRecoveryTargetService.RecoveryListener recoveryListener,
+        RecoveryListener recoveryListener,
         CheckedConsumer<ActionListener<Boolean>, Exception> action
     ) {
         markAsRecovering(reason, recoveryState); // mark the shard as recovering on the cluster state thread
         threadPool.generic().execute(ActionRunnable.wrap(ActionListener.wrap(r -> {
             if (r) {
-                recoveryListener.onRecoveryDone(recoveryState);
+                recoveryListener.onDone(recoveryState);
             }
-        }, e -> recoveryListener.onRecoveryFailure(recoveryState, new RecoveryFailedException(recoveryState, null, e), true)), action));
+        }, e -> recoveryListener.onFailure(recoveryState, new RecoveryFailedException(recoveryState, null, e), true)), action));
     }
 
     /**
@@ -3070,10 +3733,15 @@ private static void persistMetadata(
                 writeReason = "routing changed from " + currentRouting + " to " + newRouting;
             }
             logger.trace("{} writing shard state, reason [{}]", shardId, writeReason);
+
+            final ShardStateMetadata.IndexDataLocation indexDataLocation = IndexSettings.SEARCHABLE_SNAPSHOT_REPOSITORY.exists(
+                indexSettings.getSettings()
+            ) ? ShardStateMetadata.IndexDataLocation.REMOTE : ShardStateMetadata.IndexDataLocation.LOCAL;
             final ShardStateMetadata newShardStateMetadata = new ShardStateMetadata(
                 newRouting.primary(),
                 indexSettings.getUUID(),
-                newRouting.allocationId()
+                newRouting.allocationId(),
+                indexDataLocation
             );
             ShardStateMetadata.FORMAT.writeAndCleanup(newShardStateMetadata, shardPath.getShardStatePath());
         } else {
@@ -3085,7 +3753,7 @@ private DocumentMapperForType docMapper() {
         return mapperService.documentMapperWithAutoCreate();
     }
 
-    private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) {
+    private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) throws IOException {
         final Sort indexSort = indexSortSupplier.get();
         final Engine.Warmer warmer = reader -> {
             assert Thread.holdsLock(mutex) == false : "warming engine under mutex";
@@ -3095,13 +3763,40 @@ private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) {
             }
         };
 
+        internalRefreshListener.clear();
+        internalRefreshListener.add(new RefreshMetricUpdater(refreshMetric));
+        if (indexSettings.isSegRepEnabled()) {
+            internalRefreshListener.add(new ReplicationCheckpointUpdater());
+        }
+        if (this.checkpointPublisher != null && shardRouting.primary() && indexSettings.isSegRepLocalEnabled()) {
+            internalRefreshListener.add(new CheckpointRefreshListener(this, this.checkpointPublisher));
+        }
+
+        if (isRemoteStoreEnabled()) {
+            internalRefreshListener.add(
+                new RemoteStoreRefreshListener(
+                    this,
+                    this.checkpointPublisher,
+                    remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId())
+                )
+            );
+        }
+
+        /**
+         * With segment replication enabled for primary relocation, recover replica shard initially as read only and
+         * change to a writeable engine during relocation handoff after a round of segment replication.
+         */
+        boolean isReadOnlyReplica = indexSettings.isSegRepEnabled()
+            && (shardRouting.primary() == false
+                || (shardRouting.isRelocationTarget() && recoveryState.getStage() != RecoveryState.Stage.FINALIZE));
+
         return this.engineConfigFactory.newEngineConfig(
             shardId,
             threadPool,
             indexSettings,
             warmer,
             store,
-            indexSettings.getMergePolicy(),
+            indexSettings.getMergePolicy(isTimeSeriesIndex),
             mapperService != null ? mapperService.indexAnalyzer() : null,
             similarityService.similarity(mapperService),
             engineConfigFactory.newCodecServiceOrDefault(indexSettings, mapperService, logger, codecService),
@@ -3111,16 +3806,44 @@ private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) {
             translogConfig,
             IndexingMemoryController.SHARD_INACTIVE_TIME_SETTING.get(indexSettings.getSettings()),
             Arrays.asList(refreshListeners, refreshPendingLocationListener),
-            Collections.singletonList(new RefreshMetricUpdater(refreshMetric)),
+            internalRefreshListener,
             indexSort,
             circuitBreakerService,
             globalCheckpointSupplier,
             replicationTracker::getRetentionLeases,
             () -> getOperationPrimaryTerm(),
-            tombstoneDocSupplier()
+            tombstoneDocSupplier(),
+            isReadOnlyReplica,
+            replicationTracker::isPrimaryMode,
+            translogFactorySupplier.apply(indexSettings, shardRouting),
+            isTimeSeriesDescSortOptimizationEnabled() ? DataStream.TIMESERIES_LEAF_SORTER : null // DESC @timestamp default order for
+            // timeseries
         );
     }
 
+    private boolean isRemoteStoreEnabled() {
+        return (remoteStore != null && shardRouting.primary());
+    }
+
+    public boolean isRemoteTranslogEnabled() {
+        return indexSettings() != null && indexSettings().isRemoteTranslogStoreEnabled();
+    }
+
+    /**
+     * @return true if segment reverse search optimization is enabled for time series based workload.
+     */
+    public boolean isTimeSeriesDescSortOptimizationEnabled() {
+        // Do not change segment order in case of index sort.
+        return isTimeSeriesIndex && getIndexSort() == null;
+    }
+
+    /**
+     * @return True if settings indicate this shard is backed by a remote snapshot, false otherwise.
+     */
+    public boolean isRemoteSnapshot() {
+        return indexSettings != null && indexSettings.isRemoteSnapshot();
+    }
+
     /**
      * Acquire a primary operation permit whenever the shard is ready for indexing. If a permit is directly available, the provided
      * ActionListener will be called on the calling thread. During relocation hand-off, permit acquisition can be delayed. The provided
@@ -3398,7 +4121,7 @@ private void innerAcquireReplicaOperationPermit(
                     final IndexShardState shardState = state();
                     // only roll translog and update primary term if shard has made it past recovery
                     // Having a new primary term here means that the old primary failed and that there is a new primary, which again
-                    // means that the master will fail this shard as all initializing shards are failed when a primary is selected
+                    // means that the cluster-manager will fail this shard as all initializing shards are failed when a primary is selected
                     // We abort early here to prevent an ongoing recovery from the failed primary to mess with the global / local checkpoint
                     if (shardState != IndexShardState.POST_RECOVERY && shardState != IndexShardState.STARTED) {
                         throw new IndexShardNotStartedException(shardId, shardState);
@@ -3414,7 +4137,9 @@ private void innerAcquireReplicaOperationPermit(
                             currentGlobalCheckpoint,
                             maxSeqNo
                         );
-                        if (currentGlobalCheckpoint < maxSeqNo) {
+                        // With Segment Replication enabled, we never want to reset a replica's engine unless
+                        // it is promoted to primary.
+                        if (currentGlobalCheckpoint < maxSeqNo && indexSettings.isSegRepEnabled() == false) {
                             resetEngineToGlobalCheckpoint();
                         } else {
                             getEngine().rollTranslogGeneration();
@@ -3464,21 +4189,43 @@ public List<String> getActiveOperations() {
 
     private static AsyncIOProcessor<Translog.Location> createTranslogSyncProcessor(
         Logger logger,
-        ThreadContext threadContext,
-        Supplier<Engine> engineSupplier
+        ThreadPool threadPool,
+        Supplier<Engine> engineSupplier,
+        boolean bufferAsyncIoProcessor,
+        Supplier<TimeValue> bufferIntervalSupplier
     ) {
-        return new AsyncIOProcessor<Translog.Location>(logger, 1024, threadContext) {
+        assert bufferAsyncIoProcessor == false || Objects.nonNull(bufferIntervalSupplier)
+            : "If bufferAsyncIoProcessor is true, then the bufferIntervalSupplier needs to be non null";
+        ThreadContext threadContext = threadPool.getThreadContext();
+        CheckedConsumer<List<Tuple<Translog.Location, Consumer<Exception>>>, IOException> writeConsumer = candidates -> {
+            try {
+                engineSupplier.get().ensureTranslogSynced(candidates.stream().map(Tuple::v1));
+            } catch (AlreadyClosedException ex) {
+                // that's fine since we already synced everything on engine close - this also is conform with the methods
+                // documentation
+            } catch (IOException ex) { // if this fails we are in deep shit - fail the request
+                logger.debug("failed to sync translog", ex);
+                throw ex;
+            }
+        };
+
+        if (bufferAsyncIoProcessor) {
+            return new BufferedAsyncIOProcessor<>(logger, 102400, threadContext, threadPool, bufferIntervalSupplier) {
+                @Override
+                protected void write(List<Tuple<Translog.Location, Consumer<Exception>>> candidates) throws IOException {
+                    writeConsumer.accept(candidates);
+                }
+
+                @Override
+                protected String getBufferProcessThreadPoolName() {
+                    return ThreadPool.Names.TRANSLOG_SYNC;
+                }
+            };
+        }
+        return new AsyncIOProcessor<>(logger, 1024, threadContext) {
             @Override
             protected void write(List<Tuple<Translog.Location, Consumer<Exception>>> candidates) throws IOException {
-                try {
-                    engineSupplier.get().ensureTranslogSynced(candidates.stream().map(Tuple::v1));
-                } catch (AlreadyClosedException ex) {
-                    // that's fine since we already synced everything on engine close - this also is conform with the methods
-                    // documentation
-                } catch (IOException ex) { // if this fails we are in deep shit - fail the request
-                    logger.debug("failed to sync translog", ex);
-                    throw ex;
-                }
+                writeConsumer.accept(candidates);
             }
         };
     }
@@ -3512,7 +4259,7 @@ public boolean isSyncNeeded() {
     /**
      * Returns the current translog durability mode
      */
-    public Translog.Durability getTranslogDurability() {
+    public Durability getTranslogDurability() {
         return indexSettings.getTranslogDurability();
     }
 
@@ -3603,6 +4350,8 @@ private RefreshListeners buildRefreshListeners() {
      * Simple struct encapsulating a shard failure
      *
      * @see IndexShard#addShardFailureCallback(Consumer)
+     *
+     * @opensearch.internal
      */
     public static final class ShardFailure {
         public final ShardRouting routing;
@@ -3640,6 +4389,7 @@ public boolean scheduledRefresh() {
         boolean listenerNeedsRefresh = refreshListeners.refreshNeeded();
         if (isReadAllowed() && (listenerNeedsRefresh || getEngine().refreshNeeded())) {
             if (listenerNeedsRefresh == false // if we have a listener that is waiting for a refresh we need to force it
+                && isSearchIdleSupported()
                 && isSearchIdle()
                 && indexSettings.isExplicitRefresh() == false
                 && active.get()) { // it must be active otherwise we might not free up segment memory once the shard became inactive
@@ -3669,6 +4419,19 @@ public final boolean isSearchIdle() {
         return (threadPool.relativeTimeInMillis() - lastSearcherAccess.get()) >= indexSettings.getSearchIdleAfter().getMillis();
     }
 
+    /**
+     *
+     * Returns true if this shard supports search idle.
+     *
+     * Indices using Segment Replication will ignore search idle unless there are no replicas.
+     * Primary shards push out new segments only
+     * after a refresh, so we don't want to wait for a search to trigger that cycle. Replicas will only refresh after receiving
+     * a new set of segments.
+     */
+    public final boolean isSearchIdleSupported() {
+        return indexSettings.isSegRepEnabled() == false || indexSettings.getNumberOfReplicas() == 0;
+    }
+
     /**
      * Returns the last timestamp the searcher was accessed. This is a relative timestamp in milliseconds.
      */
@@ -3760,7 +4523,8 @@ public void addRefreshListener(Translog.Location location, Consumer<Boolean> lis
                 readAllowed = isReadAllowed();
             }
         }
-        if (readAllowed) {
+        // NRT Replicas will not accept refresh listeners.
+        if (readAllowed && isSegmentReplicationAllowed() == false) {
             refreshListeners.addOrNotify(location, listener);
         } else {
             // we're not yet ready fo ready for reads, just ignore refresh cycles
@@ -3768,6 +4532,11 @@ public void addRefreshListener(Translog.Location location, Consumer<Boolean> lis
         }
     }
 
+    /**
+     * Metrics updater for a refresh
+     *
+     * @opensearch.internal
+     */
     private static class RefreshMetricUpdater implements ReferenceManager.RefreshListener {
 
         private final MeanMetric refreshMetric;
@@ -3804,6 +4573,33 @@ public void afterRefresh(boolean didRefresh) throws IOException {
         }
     }
 
+    /**
+     * Refresh listener to update the Shard's ReplicationCheckpoint post refresh.
+     */
+    private class ReplicationCheckpointUpdater implements ReferenceManager.RefreshListener {
+        @Override
+        public void beforeRefresh() throws IOException {}
+
+        @Override
+        public void afterRefresh(boolean didRefresh) throws IOException {
+            if (didRefresh) {
+                // We're only starting to track the replication checkpoint. The timers for replication are started when
+                // the checkpoint is published. This is done so that the timers do not include the time spent by primary
+                // in uploading the segments to remote store.
+                updateReplicationCheckpoint();
+            }
+        }
+    }
+
+    private void updateReplicationCheckpoint() {
+        final Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> tuple = getLatestSegmentInfosAndCheckpoint();
+        try (final GatedCloseable<SegmentInfos> ignored = tuple.v1()) {
+            replicationTracker.setLatestReplicationCheckpoint(tuple.v2());
+        } catch (IOException e) {
+            throw new OpenSearchException("Error Closing SegmentInfos Snapshot", e);
+        }
+    }
+
     private EngineConfig.TombstoneDocSupplier tombstoneDocSupplier() {
         final RootObjectMapper.Builder noopRootMapper = new RootObjectMapper.Builder("__noop");
         final DocumentMapper noopDocumentMapper = mapperService != null
@@ -3872,6 +4668,16 @@ public GatedCloseable<IndexCommit> acquireSafeIndexCommit() {
                     }
                 }
 
+                @Override
+                public GatedCloseable<SegmentInfos> getSegmentInfosSnapshot() {
+                    synchronized (engineMutex) {
+                        if (newEngineReference.get() == null) {
+                            throw new AlreadyClosedException("engine was closed");
+                        }
+                        return newEngineReference.get().getSegmentInfosSnapshot();
+                    }
+                }
+
                 @Override
                 public void close() throws IOException {
                     assert Thread.holdsLock(engineMutex);
@@ -3885,6 +4691,12 @@ public void close() throws IOException {
                 }
             };
             IOUtils.close(currentEngineReference.getAndSet(readOnlyEngine));
+            if (indexSettings.isRemoteStoreEnabled()) {
+                syncSegmentsFromRemoteSegmentStore(false);
+            }
+            if (indexSettings.isRemoteTranslogStoreEnabled() && shardRouting.primary()) {
+                syncRemoteTranslogAndUpdateGlobalCheckpoint();
+            }
             newEngineReference.set(engineFactory.newReadWriteEngine(newEngineConfig(replicationTracker)));
             onNewEngine(newEngineReference.get());
         }
@@ -3896,7 +4708,13 @@ public void close() throws IOException {
                 // TODO: add a dedicate recovery stats for the reset translog
             }
         );
-        newEngineReference.get().recoverFromTranslog(translogRunner, globalCheckpoint);
+
+        // When the new engine is created, translogs are synced from remote store onto local. Since remote store is the source
+        // of truth for translog, we play all translogs that exists locally. Otherwise, the recoverUpto happens upto global checkpoint.
+        // We also replay all local translog ops with Segment replication, because on engine swap our local translog may
+        // hold more ops than the global checkpoint.
+        long recoverUpto = this.isRemoteTranslogEnabled() || indexSettings().isSegRepEnabled() ? Long.MAX_VALUE : globalCheckpoint;
+        newEngineReference.get().recoverFromTranslog(translogRunner, recoverUpto);
         newEngineReference.get().refresh("reset_engine");
         synchronized (engineMutex) {
             verifyNotClosed();
@@ -3910,6 +4728,250 @@ public void close() throws IOException {
         onSettingsChanged();
     }
 
+    private void syncRemoteTranslogAndUpdateGlobalCheckpoint() throws IOException {
+        syncTranslogFilesFromRemoteTranslog();
+        loadGlobalCheckpointToReplicationTracker();
+    }
+
+    public void deleteTranslogFilesFromRemoteTranslog() throws IOException {
+        TranslogFactory translogFactory = translogFactorySupplier.apply(indexSettings, shardRouting);
+        assert translogFactory instanceof RemoteBlobStoreInternalTranslogFactory;
+        Repository repository = ((RemoteBlobStoreInternalTranslogFactory) translogFactory).getRepository();
+        RemoteFsTranslog.cleanup(repository, shardId, getThreadPool());
+    }
+
+    public void syncTranslogFilesFromRemoteTranslog() throws IOException {
+        TranslogFactory translogFactory = translogFactorySupplier.apply(indexSettings, shardRouting);
+        assert translogFactory instanceof RemoteBlobStoreInternalTranslogFactory;
+        Repository repository = ((RemoteBlobStoreInternalTranslogFactory) translogFactory).getRepository();
+        RemoteFsTranslog.download(repository, shardId, getThreadPool(), shardPath().resolveTranslog(), logger);
+    }
+
+    /**
+     * Downloads segments from remote segment store
+     * @param overrideLocal flag to override local segment files with those in remote store.
+     * @throws IOException if exception occurs while reading segments from remote store.
+     */
+    public void syncSegmentsFromRemoteSegmentStore(boolean overrideLocal) throws IOException {
+        syncSegmentsFromRemoteSegmentStore(overrideLocal, () -> {});
+    }
+
+    /**
+     * Downloads segments from remote segment store along with updating the access time of the recovery target.
+     * @param overrideLocal flag to override local segment files with those in remote store.
+     * @param onFileSync runnable that updates the access time when run.
+     * @throws IOException if exception occurs while reading segments from remote store.
+     */
+    public void syncSegmentsFromRemoteSegmentStore(boolean overrideLocal, final Runnable onFileSync) throws IOException {
+        assert indexSettings.isRemoteStoreEnabled();
+        logger.trace("Downloading segments from remote segment store");
+        RemoteSegmentStoreDirectory remoteDirectory = getRemoteDirectory();
+        // We need to call RemoteSegmentStoreDirectory.init() in order to get latest metadata of the files that
+        // are uploaded to the remote segment store.
+        RemoteSegmentMetadata remoteSegmentMetadata = remoteDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = remoteDirectory
+            .getSegmentsUploadedToRemoteStore()
+            .entrySet()
+            .stream()
+            .filter(entry -> entry.getKey().startsWith(IndexFileNames.SEGMENTS) == false)
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        store.incRef();
+        remoteStore.incRef();
+        try {
+            final Directory storeDirectory;
+            if (recoveryState.getStage() == RecoveryState.Stage.INDEX) {
+                storeDirectory = new StoreRecovery.StatsDirectoryWrapper(store.directory(), recoveryState.getIndex());
+                for (String file : uploadedSegments.keySet()) {
+                    long checksum = Long.parseLong(uploadedSegments.get(file).getChecksum());
+                    if (overrideLocal || localDirectoryContains(storeDirectory, file, checksum) == false) {
+                        recoveryState.getIndex().addFileDetail(file, uploadedSegments.get(file).getLength(), false);
+                    } else {
+                        recoveryState.getIndex().addFileDetail(file, uploadedSegments.get(file).getLength(), true);
+                    }
+                }
+            } else {
+                storeDirectory = store.directory();
+            }
+            copySegmentFiles(storeDirectory, remoteDirectory, null, uploadedSegments, overrideLocal, onFileSync);
+
+            if (remoteSegmentMetadata != null) {
+                final SegmentInfos infosSnapshot = store.buildSegmentInfos(
+                    remoteSegmentMetadata.getSegmentInfosBytes(),
+                    remoteSegmentMetadata.getGeneration()
+                );
+                long processedLocalCheckpoint = Long.parseLong(infosSnapshot.getUserData().get(LOCAL_CHECKPOINT_KEY));
+                // delete any other commits, we want to start the engine only from a new commit made with the downloaded infos bytes.
+                // Extra segments will be wiped on engine open.
+                for (String file : List.of(store.directory().listAll())) {
+                    if (file.startsWith(IndexFileNames.SEGMENTS)) {
+                        store.deleteQuiet(file);
+                    }
+                }
+                assert Arrays.stream(store.directory().listAll()).filter(f -> f.startsWith(IndexFileNames.SEGMENTS)).findAny().isEmpty()
+                    : "There should not be any segments file in the dir";
+                store.commitSegmentInfos(infosSnapshot, processedLocalCheckpoint, processedLocalCheckpoint);
+            }
+        } catch (IOException e) {
+            throw new IndexShardRecoveryException(shardId, "Exception while copying segment files from remote segment store", e);
+        } finally {
+            store.decRef();
+            remoteStore.decRef();
+        }
+    }
+
+    /**
+     * Downloads segments from given remote segment store for a specific commit.
+     * @param overrideLocal flag to override local segment files with those in remote store
+     * @param sourceRemoteDirectory RemoteSegmentDirectory Instance from which we need to sync segments
+     * @param primaryTerm Primary Term for shard at the time of commit operation for which we are syncing segments
+     * @param commitGeneration commit generation at the time of commit operation for which we are syncing segments
+     * @throws IOException if exception occurs while reading segments from remote store
+     */
+    public void syncSegmentsFromGivenRemoteSegmentStore(
+        boolean overrideLocal,
+        RemoteSegmentStoreDirectory sourceRemoteDirectory,
+        long primaryTerm,
+        long commitGeneration
+    ) throws IOException {
+        logger.trace("Downloading segments from given remote segment store");
+        RemoteSegmentStoreDirectory remoteDirectory = null;
+        if (remoteStore != null) {
+            remoteDirectory = getRemoteDirectory();
+            remoteDirectory.init();
+            remoteStore.incRef();
+        }
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = sourceRemoteDirectory
+            .initializeToSpecificCommit(primaryTerm, commitGeneration)
+            .getMetadata();
+        final Directory storeDirectory = store.directory();
+        store.incRef();
+
+        try {
+            String segmentsNFile = copySegmentFiles(
+                storeDirectory,
+                sourceRemoteDirectory,
+                remoteDirectory,
+                uploadedSegments,
+                overrideLocal,
+                () -> {}
+            );
+            if (segmentsNFile != null) {
+                try (
+                    ChecksumIndexInput indexInput = new BufferedChecksumIndexInput(
+                        storeDirectory.openInput(segmentsNFile, IOContext.DEFAULT)
+                    )
+                ) {
+                    SegmentInfos infosSnapshot = SegmentInfos.readCommit(store.directory(), indexInput, commitGeneration);
+                    long processedLocalCheckpoint = Long.parseLong(infosSnapshot.getUserData().get(LOCAL_CHECKPOINT_KEY));
+                    if (remoteStore != null) {
+                        store.commitSegmentInfos(infosSnapshot, processedLocalCheckpoint, processedLocalCheckpoint);
+                    } else {
+                        store.directory().sync(infosSnapshot.files(true));
+                        store.directory().syncMetaData();
+                    }
+                }
+            }
+        } catch (IOException e) {
+            throw new IndexShardRecoveryException(shardId, "Exception while copying segment files from remote segment store", e);
+        } finally {
+            store.decRef();
+            if (remoteStore != null) {
+                remoteStore.decRef();
+            }
+        }
+    }
+
+    private String copySegmentFiles(
+        Directory storeDirectory,
+        RemoteSegmentStoreDirectory sourceRemoteDirectory,
+        RemoteSegmentStoreDirectory targetRemoteDirectory,
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments,
+        boolean overrideLocal,
+        final Runnable onFileSync
+    ) throws IOException {
+        Set<String> toDownloadSegments = new HashSet<>();
+        Set<String> skippedSegments = new HashSet<>();
+        String segmentNFile = null;
+
+        try {
+            if (overrideLocal) {
+                for (String file : storeDirectory.listAll()) {
+                    storeDirectory.deleteFile(file);
+                }
+            }
+
+            for (String file : uploadedSegments.keySet()) {
+                long checksum = Long.parseLong(uploadedSegments.get(file).getChecksum());
+                if (overrideLocal || localDirectoryContains(storeDirectory, file, checksum) == false) {
+                    toDownloadSegments.add(file);
+                } else {
+                    skippedSegments.add(file);
+                }
+
+                if (file.startsWith(IndexFileNames.SEGMENTS)) {
+                    assert segmentNFile == null : "There should be only one SegmentInfosSnapshot file";
+                    segmentNFile = file;
+                }
+            }
+
+            if (toDownloadSegments.isEmpty() == false) {
+                try {
+                    downloadSegments(storeDirectory, sourceRemoteDirectory, targetRemoteDirectory, toDownloadSegments, onFileSync);
+                } catch (Exception e) {
+                    throw new IOException("Error occurred when downloading segments from remote store", e);
+                }
+            }
+        } finally {
+            logger.trace("Downloaded segments here: {}", toDownloadSegments);
+            logger.trace("Skipped download for segments here: {}", skippedSegments);
+        }
+
+        return segmentNFile;
+    }
+
+    private void downloadSegments(
+        Directory storeDirectory,
+        RemoteSegmentStoreDirectory sourceRemoteDirectory,
+        RemoteSegmentStoreDirectory targetRemoteDirectory,
+        Set<String> toDownloadSegments,
+        final Runnable onFileSync
+    ) throws IOException {
+        final Path indexPath = store.shardPath() == null ? null : store.shardPath().resolveIndex();
+        for (String segment : toDownloadSegments) {
+            final PlainActionFuture<String> segmentListener = PlainActionFuture.newFuture();
+            sourceRemoteDirectory.copyTo(segment, storeDirectory, indexPath, segmentListener);
+            segmentListener.actionGet();
+            onFileSync.run();
+            if (targetRemoteDirectory != null) {
+                targetRemoteDirectory.copyFrom(storeDirectory, segment, segment, IOContext.DEFAULT);
+            }
+        }
+    }
+
+    private boolean localDirectoryContains(Directory localDirectory, String file, long checksum) {
+        try (IndexInput indexInput = localDirectory.openInput(file, IOContext.DEFAULT)) {
+            if (checksum == CodecUtil.retrieveChecksum(indexInput)) {
+                return true;
+            } else {
+                logger.warn("Checksum mismatch between local and remote segment file: {}, will override local file", file);
+                // If there is a checksum mismatch and we are not serving reads it is safe to go ahead and delete the file now.
+                // Outside of engine resets this method will be invoked during recovery so this is safe.
+                if (isReadAllowed() == false) {
+                    localDirectory.deleteFile(file);
+                } else {
+                    // segment conflict with remote store while the shard is serving reads.
+                    failShard("Local copy of segment " + file + " has a different checksum than the version in remote store", null);
+                }
+            }
+        } catch (NoSuchFileException | FileNotFoundException e) {
+            logger.debug("File {} does not exist in local FS, downloading from remote store", file);
+        } catch (IOException e) {
+            logger.warn("Exception while reading checksum of file: {}, this can happen if file is corrupted", file);
+        }
+        return false;
+    }
+
     /**
      * Returns the maximum sequence number of either update or delete operations have been processed in this shard
      * or the sequence number from {@link #advanceMaxSeqNoOfUpdatesOrDeletes(long)}. An index request is considered
@@ -3954,4 +5016,27 @@ public void verifyShardBeforeIndexClosing() throws IllegalStateException {
     RetentionLeaseSyncer getRetentionLeaseSyncer() {
         return retentionLeaseSyncer;
     }
+
+    /**
+     * Fetch the latest SegmentInfos held by the shard's underlying Engine, wrapped
+     * by a a {@link GatedCloseable} to ensure files are not deleted/merged away.
+     *
+     * @throws EngineException - When segment infos cannot be safely retrieved
+     */
+    public GatedCloseable<SegmentInfos> getSegmentInfosSnapshot() {
+        return getEngine().getSegmentInfosSnapshot();
+    }
+
+    private TimeValue getRemoteTranslogUploadBufferInterval(Supplier<TimeValue> clusterRemoteTranslogBufferIntervalSupplier) {
+        assert Objects.nonNull(clusterRemoteTranslogBufferIntervalSupplier) : "remote translog buffer interval supplier is null";
+        if (indexSettings().isRemoteTranslogBufferIntervalExplicit()) {
+            return indexSettings().getRemoteTranslogUploadBufferInterval();
+        }
+        return clusterRemoteTranslogBufferIntervalSupplier.get();
+    }
+
+    // Exclusively for testing, please do not use it elsewhere.
+    public AsyncIOProcessor<Translog.Location> getTranslogSyncProcessor() {
+        return translogSyncProcessor;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardClosedException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardClosedException.java
index a7f58ddfb84d0..8b4c9a188e00c 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardClosedException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardClosedException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if trying to operate on a closed Index Shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShardClosedException extends IllegalIndexShardStateException {
     public IndexShardClosedException(ShardId shardId) {
         super(shardId, IndexShardState.CLOSED, "Closed");
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardComponent.java b/server/src/main/java/org/opensearch/index/shard/IndexShardComponent.java
index 9f8ae26ca3110..cf9602ebd76d7 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardComponent.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardComponent.java
@@ -32,8 +32,14 @@
 
 package org.opensearch.index.shard;
 
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 
+/**
+ * Base interface for an IndexShard
+ *
+ * @opensearch.internal
+ */
 public interface IndexShardComponent {
 
     ShardId shardId();
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardNotRecoveringException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardNotRecoveringException.java
index 9245119f9bf23..75af4ef53e638 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardNotRecoveringException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardNotRecoveringException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an index shard is not recovering
+ *
+ * @opensearch.internal
+ */
 public class IndexShardNotRecoveringException extends IllegalIndexShardStateException {
 
     public IndexShardNotRecoveringException(ShardId shardId, IndexShardState currentState) {
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardNotStartedException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardNotStartedException.java
index b4be8cc08a6b6..7f37ae2a00873 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardNotStartedException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardNotStartedException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when trying to operate on an Index Shard that hasn't been started
+ *
+ * @opensearch.internal
+ */
 public class IndexShardNotStartedException extends IllegalIndexShardStateException {
 
     public IndexShardNotStartedException(ShardId shardId, IndexShardState currentState) {
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardOperationPermits.java b/server/src/main/java/org/opensearch/index/shard/IndexShardOperationPermits.java
index 9474a7dc99bb9..da51530586893 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardOperationPermits.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardOperationPermits.java
@@ -32,9 +32,7 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.support.ContextPreservingActionListener;
 import org.opensearch.common.CheckedRunnable;
@@ -43,7 +41,10 @@
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.RunOnce;
 import org.opensearch.common.util.concurrent.ThreadContext.StoredContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -64,6 +65,8 @@
  * between terms) we immediately delay all operations to a queue, obtain all available permits, and wait for outstanding operations to drain
  * and return their permits. Delayed operations will acquire permits and be completed after the operation that blocked all operations has
  * completed.
+ *
+ * @opensearch.internal
  */
 final class IndexShardOperationPermits implements Closeable {
 
@@ -359,6 +362,11 @@ List<String> getActiveOperations() {
             .collect(Collectors.toList());
     }
 
+    /**
+     * Represents a delayed operation
+     *
+     * @opensearch.internal
+     */
     private static class DelayedOperation {
         private final ActionListener<Releasable> listener;
         private final String debugInfo;
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveringException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveringException.java
index 7a71dcdf207ca..9372ff222d6f0 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveringException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveringException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when there is an error recovering an Index Shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShardRecoveringException extends IllegalIndexShardStateException {
 
     public IndexShardRecoveringException(ShardId shardId) {
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveryException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveryException.java
index 1c0d51828c6dd..0d8947b5bebb6 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveryException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardRecoveryException.java
@@ -33,10 +33,16 @@
 package org.opensearch.index.shard;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown when there is an error on recovery of Index Shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShardRecoveryException extends OpenSearchException {
     public IndexShardRecoveryException(ShardId shardId, String msg, Throwable cause) {
         super(msg, cause);
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardRelocatedException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardRelocatedException.java
index fbe0306bbc006..5176b23edcf82 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardRelocatedException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardRelocatedException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is an error relocating an index shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShardRelocatedException extends IllegalIndexShardStateException {
 
     public IndexShardRelocatedException(ShardId shardId) {
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardStartedException.java b/server/src/main/java/org/opensearch/index/shard/IndexShardStartedException.java
index 3582341b92a55..a724952e37707 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardStartedException.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardStartedException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is an error starting an index shard
+ *
+ * @opensearch.internal
+ */
 public class IndexShardStartedException extends IllegalIndexShardStateException {
 
     public IndexShardStartedException(ShardId shardId) {
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShardState.java b/server/src/main/java/org/opensearch/index/shard/IndexShardState.java
index 526dcdad87063..dc6f2fc3a86d9 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShardState.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShardState.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.index.shard;
 
+/**
+ * Index Shard States
+ *
+ * @opensearch.internal
+ */
 public enum IndexShardState {
     CREATED((byte) 0),
     RECOVERING((byte) 1),
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexingOperationListener.java b/server/src/main/java/org/opensearch/index/shard/IndexingOperationListener.java
index aff44203cca22..ccc4cd336cff7 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexingOperationListener.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexingOperationListener.java
@@ -33,12 +33,15 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 
 import java.util.List;
 
 /**
  * An indexing listener for indexing, delete, events.
+ *
+ * @opensearch.internal
  */
 public interface IndexingOperationListener {
 
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexingStats.java b/server/src/main/java/org/opensearch/index/shard/IndexingStats.java
index bdc5373e0b9b3..89cbc59403faf 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexingStats.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexingStats.java
@@ -33,22 +33,117 @@
 package org.opensearch.index.shard;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
 
+/**
+ * Tracks indexing statistics
+ *
+ * @opensearch.internal
+ */
 public class IndexingStats implements Writeable, ToXContentFragment {
 
+    /**
+     * Internal statistics for indexing
+     *
+     * @opensearch.internal
+     */
     public static class Stats implements Writeable, ToXContentFragment {
 
+        /**
+         * Tracks item level rest category class codes during indexing
+         *
+         * @opensearch.internal
+         */
+        public static class DocStatusStats implements Writeable, ToXContentFragment {
+
+            final AtomicLong[] docStatusCounter;
+
+            public DocStatusStats() {
+                docStatusCounter = new AtomicLong[5];
+                for (int i = 0; i < docStatusCounter.length; ++i) {
+                    docStatusCounter[i] = new AtomicLong(0);
+                }
+            }
+
+            public DocStatusStats(StreamInput in) throws IOException {
+                docStatusCounter = in.readArray(i -> new AtomicLong(i.readLong()), AtomicLong[]::new);
+
+                assert docStatusCounter.length == 5 : "Length of incoming array should be 5! Got " + docStatusCounter.length;
+            }
+
+            /**
+             * Increment counter for status
+             *
+             * @param status {@link RestStatus}
+             */
+            public void inc(final RestStatus status) {
+                add(status, 1L);
+            }
+
+            /**
+             * Increment counter for status by count
+             *
+             * @param status {@link RestStatus}
+             * @param delta The value to add
+             */
+            void add(final RestStatus status, final long delta) {
+                docStatusCounter[status.getStatusFamilyCode() - 1].addAndGet(delta);
+            }
+
+            /**
+             * Accumulate stats from the passed Object
+             *
+             * @param stats Instance storing {@link DocStatusStats}
+             */
+            public void add(final DocStatusStats stats) {
+                if (null == stats) {
+                    return;
+                }
+
+                for (int i = 0; i < docStatusCounter.length; ++i) {
+                    docStatusCounter[i].addAndGet(stats.docStatusCounter[i].longValue());
+                }
+            }
+
+            public AtomicLong[] getDocStatusCounter() {
+                return docStatusCounter;
+            }
+
+            @Override
+            public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+                builder.startObject(Fields.DOC_STATUS);
+
+                for (int i = 0; i < docStatusCounter.length; ++i) {
+                    long value = docStatusCounter[i].longValue();
+
+                    if (value > 0) {
+                        String key = i + 1 + "xx";
+                        builder.field(key, value);
+                    }
+                }
+
+                return builder.endObject();
+            }
+
+            @Override
+            public void writeTo(StreamOutput out) throws IOException {
+                out.writeArray((o, v) -> o.writeLong(v.longValue()), docStatusCounter);
+            }
+
+        }
+
         private long indexCount;
         private long indexTimeInMillis;
         private long indexCurrent;
@@ -59,8 +154,11 @@ public static class Stats implements Writeable, ToXContentFragment {
         private long noopUpdateCount;
         private long throttleTimeInMillis;
         private boolean isThrottled;
+        private final DocStatusStats docStatusStats;
 
-        Stats() {}
+        Stats() {
+            docStatusStats = new DocStatusStats();
+        }
 
         public Stats(StreamInput in) throws IOException {
             indexCount = in.readVLong();
@@ -73,6 +171,12 @@ public Stats(StreamInput in) throws IOException {
             noopUpdateCount = in.readVLong();
             isThrottled = in.readBoolean();
             throttleTimeInMillis = in.readLong();
+
+            if (in.getVersion().onOrAfter(Version.V_2_11_0)) {
+                docStatusStats = in.readOptionalWriteable(DocStatusStats::new);
+            } else {
+                docStatusStats = null;
+            }
         }
 
         public Stats(
@@ -85,7 +189,8 @@ public Stats(
             long deleteCurrent,
             long noopUpdateCount,
             boolean isThrottled,
-            long throttleTimeInMillis
+            long throttleTimeInMillis,
+            DocStatusStats docStatusStats
         ) {
             this.indexCount = indexCount;
             this.indexTimeInMillis = indexTimeInMillis;
@@ -97,6 +202,7 @@ public Stats(
             this.noopUpdateCount = noopUpdateCount;
             this.isThrottled = isThrottled;
             this.throttleTimeInMillis = throttleTimeInMillis;
+            this.docStatusStats = docStatusStats;
         }
 
         public void add(Stats stats) {
@@ -111,8 +217,10 @@ public void add(Stats stats) {
 
             noopUpdateCount += stats.noopUpdateCount;
             throttleTimeInMillis += stats.throttleTimeInMillis;
-            if (isThrottled != stats.isThrottled) {
-                isThrottled = true; // When combining if one is throttled set result to throttled.
+            isThrottled |= stats.isThrottled; // When combining if one is throttled set result to throttled.
+
+            if (getDocStatusStats() != null) {
+                getDocStatusStats().add(stats.getDocStatusStats());
             }
         }
 
@@ -183,6 +291,10 @@ public long getNoopUpdateCount() {
             return noopUpdateCount;
         }
 
+        public DocStatusStats getDocStatusStats() {
+            return docStatusStats;
+        }
+
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             out.writeVLong(indexCount);
@@ -196,6 +308,9 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(isThrottled);
             out.writeLong(throttleTimeInMillis);
 
+            if (out.getVersion().onOrAfter(Version.V_2_11_0)) {
+                out.writeOptionalWriteable(docStatusStats);
+            }
         }
 
         @Override
@@ -213,8 +328,14 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
             builder.field(Fields.IS_THROTTLED, isThrottled);
             builder.humanReadableField(Fields.THROTTLED_TIME_IN_MILLIS, Fields.THROTTLED_TIME, getThrottleTime());
+
+            if (getDocStatusStats() != null) {
+                getDocStatusStats().toXContent(builder, params);
+            }
+
             return builder;
         }
+
     }
 
     private final Stats totalStats;
@@ -264,7 +385,12 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
         return builder;
     }
 
-    static final class Fields {
+    /**
+     * Fields for indexing statistics
+     *
+     * @opensearch.internal
+     */
+    private static final class Fields {
         static final String INDEXING = "indexing";
         static final String INDEX_TOTAL = "index_total";
         static final String INDEX_TIME = "index_time";
@@ -279,6 +405,7 @@ static final class Fields {
         static final String IS_THROTTLED = "is_throttled";
         static final String THROTTLED_TIME_IN_MILLIS = "throttle_time_in_millis";
         static final String THROTTLED_TIME = "throttle_time";
+        static final String DOC_STATUS = "doc_status";
     }
 
     @Override
@@ -288,4 +415,5 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(false);
         }
     }
+
 }
diff --git a/server/src/main/java/org/opensearch/index/shard/InternalIndexingStats.java b/server/src/main/java/org/opensearch/index/shard/InternalIndexingStats.java
index 76d64ab918163..55b65bb4be6d8 100644
--- a/server/src/main/java/org/opensearch/index/shard/InternalIndexingStats.java
+++ b/server/src/main/java/org/opensearch/index/shard/InternalIndexingStats.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 
 import java.util.concurrent.TimeUnit;
@@ -41,6 +42,8 @@
 /**
  * Internal class that maintains relevant indexing statistics / metrics.
  * @see IndexShard
+ *
+ * @opensearch.internal
  */
 final class InternalIndexingStats implements IndexingOperationListener {
     private final StatsHolder totalStats = new StatsHolder();
@@ -127,6 +130,11 @@ void noopUpdate() {
         totalStats.noopUpdates.inc();
     }
 
+    /**
+     * Holder for base indexing statistics
+     *
+     * @opensearch.internal
+     */
     static class StatsHolder {
         private final MeanMetric indexMetric = new MeanMetric();
         private final MeanMetric deleteMetric = new MeanMetric();
@@ -146,7 +154,8 @@ IndexingStats.Stats stats(boolean isThrottled, long currentThrottleMillis) {
                 deleteCurrent.count(),
                 noopUpdates.count(),
                 isThrottled,
-                TimeUnit.MILLISECONDS.toMillis(currentThrottleMillis)
+                TimeUnit.MILLISECONDS.toMillis(currentThrottleMillis),
+                new IndexingStats.Stats.DocStatusStats()
             );
         }
     }
diff --git a/server/src/main/java/org/opensearch/index/shard/LocalShardSnapshot.java b/server/src/main/java/org/opensearch/index/shard/LocalShardSnapshot.java
index 98556db3ae138..ee96b31a3a727 100644
--- a/server/src/main/java/org/opensearch/index/shard/LocalShardSnapshot.java
+++ b/server/src/main/java/org/opensearch/index/shard/LocalShardSnapshot.java
@@ -41,7 +41,7 @@
 import org.apache.lucene.store.NoLockFactory;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.concurrent.GatedCloseable;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.store.Store;
 
@@ -51,6 +51,11 @@
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+/**
+ * A shard snapshot stored locally
+ *
+ * @opensearch.internal
+ */
 final class LocalShardSnapshot implements Closeable {
     private final IndexShard shard;
     private final Store store;
diff --git a/server/src/main/java/org/opensearch/index/shard/OpenSearchMergePolicy.java b/server/src/main/java/org/opensearch/index/shard/OpenSearchMergePolicy.java
index 28ae3f0b30679..258a283c63476 100644
--- a/server/src/main/java/org/opensearch/index/shard/OpenSearchMergePolicy.java
+++ b/server/src/main/java/org/opensearch/index/shard/OpenSearchMergePolicy.java
@@ -56,6 +56,8 @@
  * <p>
  * For now, this {@link MergePolicy} takes care of moving versions that used to
  * be stored as payloads to numeric doc values.
+ *
+ * @opensearch.internal
  */
 public final class OpenSearchMergePolicy extends FilterMergePolicy {
 
diff --git a/server/src/main/java/org/opensearch/index/shard/PrimaryReplicaSyncer.java b/server/src/main/java/org/opensearch/index/shard/PrimaryReplicaSyncer.java
index 726d2925177fa..875eda5473806 100644
--- a/server/src/main/java/org/opensearch/index/shard/PrimaryReplicaSyncer.java
+++ b/server/src/main/java/org/opensearch/index/shard/PrimaryReplicaSyncer.java
@@ -33,26 +33,27 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.resync.ResyncReplicationRequest;
 import org.opensearch.action.resync.ResyncReplicationResponse;
 import org.opensearch.action.resync.TransportResyncReplicationAction;
-import org.opensearch.common.Strings;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.transport.TransportService;
 
@@ -65,6 +66,11 @@
 
 import static java.util.Objects.requireNonNull;
 
+/**
+ * Syncer for Primary replica
+ *
+ * @opensearch.internal
+ */
 public class PrimaryReplicaSyncer {
 
     private static final Logger logger = LogManager.getLogger(PrimaryReplicaSyncer.class);
@@ -220,6 +226,11 @@ public void onFailure(Exception e) {
         }
     }
 
+    /**
+     * Synchronous action
+     *
+     * @opensearch.internal
+     */
     public interface SyncAction {
         void sync(
             ResyncReplicationRequest request,
@@ -230,6 +241,11 @@ void sync(
         );
     }
 
+    /**
+     * Sends a snapshot
+     *
+     * @opensearch.internal
+     */
     static class SnapshotSender extends AbstractRunnable implements ActionListener<ResyncReplicationResponse> {
         private final Logger logger;
         private final SyncAction syncAction;
@@ -343,6 +359,11 @@ protected void doRun() throws Exception {
         }
     }
 
+    /**
+     * Request to resync primary and replica
+     *
+     * @opensearch.internal
+     */
     public static class ResyncRequest extends ActionRequest {
 
         private final ShardId shardId;
@@ -374,6 +395,11 @@ public ActionRequestValidationException validate() {
         }
     }
 
+    /**
+     * Task to resync primary and replica
+     *
+     * @opensearch.internal
+     */
     public static class ResyncTask extends Task {
         private volatile String phase = "starting";
         private volatile int totalOperations;
@@ -436,6 +462,11 @@ public ResyncTask.Status getStatus() {
             return new ResyncTask.Status(phase, totalOperations, resyncedOperations, skippedOperations);
         }
 
+        /**
+         * Status for primary replica syncer
+         *
+         * @opensearch.internal
+         */
         public static class Status implements Task.Status {
             public static final String NAME = "resync";
 
@@ -484,7 +515,7 @@ public void writeTo(StreamOutput out) throws IOException {
 
             @Override
             public String toString() {
-                return Strings.toString(this);
+                return Strings.toString(MediaTypeRegistry.JSON, this);
             }
 
             @Override
diff --git a/server/src/main/java/org/opensearch/index/shard/PrimaryShardClosedException.java b/server/src/main/java/org/opensearch/index/shard/PrimaryShardClosedException.java
new file mode 100644
index 0000000000000..bcede4d6a9124
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/shard/PrimaryShardClosedException.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.index.shard;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.io.IOException;
+
+/**
+ * Exception to indicate failures are caused due to the closure of the primary
+ * shard.
+ *
+ * @opensearch.internal
+ */
+public class PrimaryShardClosedException extends IndexShardClosedException {
+    public PrimaryShardClosedException(ShardId shardId) {
+        super(shardId, "Primary closed");
+    }
+
+    public PrimaryShardClosedException(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/shard/RefreshListeners.java b/server/src/main/java/org/opensearch/index/shard/RefreshListeners.java
index 570b882e1fcab..7dbbcbb2d7d20 100644
--- a/server/src/main/java/org/opensearch/index/shard/RefreshListeners.java
+++ b/server/src/main/java/org/opensearch/index/shard/RefreshListeners.java
@@ -56,6 +56,8 @@
  * {@link IndexShard} but kept here so it can be tested without standing up the entire thing.
  *
  * When {@link Closeable#close()}d it will no longer accept listeners and flush any existing listeners.
+ *
+ * @opensearch.internal
  */
 public final class RefreshListeners implements ReferenceManager.RefreshListener, Closeable {
     private final IntSupplier getMaxRefreshListeners;
diff --git a/server/src/main/java/org/opensearch/index/shard/RemoteStoreRefreshListener.java b/server/src/main/java/org/opensearch/index/shard/RemoteStoreRefreshListener.java
new file mode 100644
index 0000000000000..577a55affd032
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/shard/RemoteStoreRefreshListener.java
@@ -0,0 +1,487 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.bulk.BackoffPolicy;
+import org.opensearch.action.support.GroupedActionListener;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.UploadListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.engine.EngineException;
+import org.opensearch.index.engine.InternalEngine;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.seqno.SequenceNumbers.LOCAL_CHECKPOINT_KEY;
+
+/**
+ * RefreshListener implementation to upload newly created segment files to the remote store
+ *
+ * @opensearch.internal
+ */
+public final class RemoteStoreRefreshListener extends CloseableRetryableRefreshListener {
+
+    private final Logger logger;
+
+    /**
+     * The initial retry interval at which the retry job gets scheduled after a failure.
+     */
+    private static final int REMOTE_REFRESH_RETRY_BASE_INTERVAL_MILLIS = 1_000;
+
+    /**
+     * In an exponential back off setup, the maximum retry interval after the retry interval increases exponentially.
+     */
+    private static final int REMOTE_REFRESH_RETRY_MAX_INTERVAL_MILLIS = 10_000;
+
+    private static final int INVALID_PRIMARY_TERM = -1;
+
+    /**
+     * Exponential back off policy with max retry interval.
+     */
+    private static final BackoffPolicy EXPONENTIAL_BACKOFF_POLICY = BackoffPolicy.exponentialEqualJitterBackoff(
+        REMOTE_REFRESH_RETRY_BASE_INTERVAL_MILLIS,
+        REMOTE_REFRESH_RETRY_MAX_INTERVAL_MILLIS
+    );
+
+    public static final Set<String> EXCLUDE_FILES = Set.of("write.lock");
+    // Visible for testing
+    public static final int LAST_N_METADATA_FILES_TO_KEEP = 10;
+
+    private final IndexShard indexShard;
+    private final Directory storeDirectory;
+    private final RemoteSegmentStoreDirectory remoteDirectory;
+    private final RemoteSegmentTransferTracker segmentTracker;
+    private final Map<String, String> localSegmentChecksumMap;
+    private long primaryTerm;
+    private volatile Iterator<TimeValue> backoffDelayIterator;
+    private final SegmentReplicationCheckpointPublisher checkpointPublisher;
+
+    public RemoteStoreRefreshListener(
+        IndexShard indexShard,
+        SegmentReplicationCheckpointPublisher checkpointPublisher,
+        RemoteSegmentTransferTracker segmentTracker
+    ) {
+        super(indexShard.getThreadPool());
+        logger = Loggers.getLogger(getClass(), indexShard.shardId());
+        this.indexShard = indexShard;
+        this.storeDirectory = indexShard.store().directory();
+        this.remoteDirectory = (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) indexShard.remoteStore().directory())
+            .getDelegate()).getDelegate();
+        localSegmentChecksumMap = new HashMap<>();
+        RemoteSegmentMetadata remoteSegmentMetadata = null;
+        if (indexShard.routingEntry().primary()) {
+            try {
+                remoteSegmentMetadata = this.remoteDirectory.init();
+            } catch (IOException e) {
+                logger.error("Exception while initialising RemoteSegmentStoreDirectory", e);
+            }
+        }
+        // initializing primary term with the primary term of latest metadata in remote store.
+        // if no metadata is present, this value will be initialized with -1.
+        this.primaryTerm = remoteSegmentMetadata != null ? remoteSegmentMetadata.getPrimaryTerm() : INVALID_PRIMARY_TERM;
+        this.segmentTracker = segmentTracker;
+        resetBackOffDelayIterator();
+        this.checkpointPublisher = checkpointPublisher;
+    }
+
+    @Override
+    public void beforeRefresh() throws IOException {}
+
+    @Override
+    protected void runAfterRefreshExactlyOnce(boolean didRefresh) {
+        if (shouldSync(didRefresh)) {
+            segmentTracker.updateLocalRefreshTimeAndSeqNo();
+            try {
+                if (this.primaryTerm != indexShard.getOperationPrimaryTerm()) {
+                    logger.debug("primaryTerm update from={} to={}", primaryTerm, indexShard.getOperationPrimaryTerm());
+                    this.primaryTerm = indexShard.getOperationPrimaryTerm();
+                    this.remoteDirectory.init();
+                }
+                try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = indexShard.getSegmentInfosSnapshot()) {
+                    Collection<String> localSegmentsPostRefresh = segmentInfosGatedCloseable.get().files(true);
+                    updateLocalSizeMapAndTracker(localSegmentsPostRefresh);
+                }
+            } catch (Throwable t) {
+                logger.error("Exception in runAfterRefreshExactlyOnce() method", t);
+            }
+        }
+    }
+
+    /**
+     * Upload new segment files created as part of the last refresh to the remote segment store.
+     * This method also uploads remote_segments_metadata file which contains metadata of each segment file uploaded.
+     *
+     * @param didRefresh true if the refresh opened a new reference
+     * @return true if the method runs successfully.
+     */
+    @Override
+    protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+        boolean successful;
+        if (shouldSync(didRefresh)) {
+            successful = syncSegments();
+        } else {
+            successful = true;
+        }
+        return successful;
+    }
+
+    private boolean shouldSync(boolean didRefresh) {
+        // The third condition exists for uploading the zero state segments where the refresh has not changed the reader reference, but it
+        // is important to upload the zero state segments so that the restore does not break.
+        return this.primaryTerm != indexShard.getOperationPrimaryTerm()
+            || didRefresh
+            || remoteDirectory.getSegmentsUploadedToRemoteStore().isEmpty();
+    }
+
+    private boolean syncSegments() {
+        if (indexShard.getReplicationTracker().isPrimaryMode() == false || indexShard.state() == IndexShardState.CLOSED) {
+            logger.debug(
+                "Skipped syncing segments with primaryMode={} indexShardState={}",
+                indexShard.getReplicationTracker().isPrimaryMode(),
+                indexShard.state()
+            );
+            // Following check is required to enable retry and make sure that we do not lose this refresh event
+            // When primary shard is restored from remote store, the recovery happens first followed by changing
+            // primaryMode to true. Due to this, the refresh that is triggered post replay of translog will not go through
+            // if following condition does not exist. The segments created as part of translog replay will not be present
+            // in the remote store.
+            return indexShard.state() != IndexShardState.STARTED || !(indexShard.getEngine() instanceof InternalEngine);
+        }
+        ReplicationCheckpoint checkpoint = indexShard.getLatestReplicationCheckpoint();
+        beforeSegmentsSync();
+        long refreshTimeMs = segmentTracker.getLocalRefreshTimeMs(), refreshClockTimeMs = segmentTracker.getLocalRefreshClockTimeMs();
+        long refreshSeqNo = segmentTracker.getLocalRefreshSeqNo();
+        long bytesBeforeUpload = segmentTracker.getUploadBytesSucceeded(), startTimeInNS = System.nanoTime();
+        final AtomicBoolean successful = new AtomicBoolean(false);
+
+        try {
+            try {
+                // if a new segments_N file is present in local that is not uploaded to remote store yet, it
+                // is considered as a first refresh post commit. A cleanup of stale commit files is triggered.
+                // This is done to avoid delete post each refresh.
+                if (isRefreshAfterCommit()) {
+                    remoteDirectory.deleteStaleSegmentsAsync(LAST_N_METADATA_FILES_TO_KEEP);
+                }
+
+                try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = indexShard.getSegmentInfosSnapshot()) {
+                    SegmentInfos segmentInfos = segmentInfosGatedCloseable.get();
+                    assert segmentInfos.getGeneration() == checkpoint.getSegmentsGen() : "SegmentInfos generation: "
+                        + segmentInfos.getGeneration()
+                        + " does not match metadata generation: "
+                        + checkpoint.getSegmentsGen();
+                    // Capture replication checkpoint before uploading the segments as upload can take some time and checkpoint can
+                    // move.
+                    long lastRefreshedCheckpoint = ((InternalEngine) indexShard.getEngine()).lastRefreshedCheckpoint();
+                    Collection<String> localSegmentsPostRefresh = segmentInfos.files(true);
+
+                    // Create a map of file name to size and update the refresh segment tracker
+                    updateLocalSizeMapAndTracker(localSegmentsPostRefresh);
+                    CountDownLatch latch = new CountDownLatch(1);
+                    ActionListener<Void> segmentUploadsCompletedListener = new LatchedActionListener<>(new ActionListener<>() {
+                        @Override
+                        public void onResponse(Void unused) {
+                            try {
+                                logger.debug("New segments upload successful");
+                                // Start metadata file upload
+                                uploadMetadata(localSegmentsPostRefresh, segmentInfos, checkpoint);
+                                logger.debug("Metadata upload successful");
+                                clearStaleFilesFromLocalSegmentChecksumMap(localSegmentsPostRefresh);
+                                onSuccessfulSegmentsSync(
+                                    refreshTimeMs,
+                                    refreshClockTimeMs,
+                                    refreshSeqNo,
+                                    lastRefreshedCheckpoint,
+                                    checkpoint
+                                );
+                                // At this point since we have uploaded new segments, segment infos and segment metadata file,
+                                // along with marking minSeqNoToKeep, upload has succeeded completely.
+                                successful.set(true);
+                            } catch (Exception e) {
+                                // We don't want to fail refresh if upload of new segments fails. The missed segments will be re-tried
+                                // as part of exponential back-off retry logic. This should not affect durability of the indexed data
+                                // with remote trans-log integration.
+                                logger.warn("Exception in post new segment upload actions", e);
+                            }
+                        }
+
+                        @Override
+                        public void onFailure(Exception e) {
+                            logger.warn("Exception while uploading new segments to the remote segment store", e);
+                        }
+                    }, latch);
+
+                    // Start the segments files upload
+                    uploadNewSegments(localSegmentsPostRefresh, segmentUploadsCompletedListener);
+                    latch.await();
+                } catch (EngineException e) {
+                    logger.warn("Exception while reading SegmentInfosSnapshot", e);
+                }
+            } catch (IOException e) {
+                // We don't want to fail refresh if upload of new segments fails. The missed segments will be re-tried
+                // as part of exponential back-off retry logic. This should not affect durability of the indexed data
+                // with remote trans-log integration.
+                logger.warn("Exception while uploading new segments to the remote segment store", e);
+            }
+        } catch (Throwable t) {
+            logger.error("Exception in RemoteStoreRefreshListener.afterRefresh()", t);
+        }
+        updateFinalStatusInSegmentTracker(successful.get(), bytesBeforeUpload, startTimeInNS);
+        // If there are failures in uploading segments, then we should retry as search idle can lead to
+        // refresh not occurring until write happens.
+        logger.debug("syncSegments runStatus={}", successful.get());
+        return successful.get();
+    }
+
+    /**
+     * Clears the stale files from the latest local segment checksum map.
+     *
+     * @param localSegmentsPostRefresh list of segment files present post refresh
+     */
+    private void clearStaleFilesFromLocalSegmentChecksumMap(Collection<String> localSegmentsPostRefresh) {
+        localSegmentChecksumMap.keySet()
+            .stream()
+            .filter(file -> !localSegmentsPostRefresh.contains(file))
+            .collect(Collectors.toSet())
+            .forEach(localSegmentChecksumMap::remove);
+    }
+
+    private void beforeSegmentsSync() {
+        // Start tracking total uploads started
+        segmentTracker.incrementTotalUploadsStarted();
+    }
+
+    private void onSuccessfulSegmentsSync(
+        long refreshTimeMs,
+        long refreshClockTimeMs,
+        long refreshSeqNo,
+        long lastRefreshedCheckpoint,
+        ReplicationCheckpoint checkpoint
+    ) {
+        // Update latest uploaded segment files name in segment tracker
+        segmentTracker.setLatestUploadedFiles(segmentTracker.getLatestLocalFileNameLengthMap().keySet());
+        // Update the remote refresh time and refresh seq no
+        updateRemoteRefreshTimeAndSeqNo(refreshTimeMs, refreshClockTimeMs, refreshSeqNo);
+        // Reset the backoffDelayIterator for the future failures
+        resetBackOffDelayIterator();
+        // Set the minimum sequence number for keeping translog
+        ((InternalEngine) indexShard.getEngine()).translogManager().setMinSeqNoToKeep(lastRefreshedCheckpoint + 1);
+        // Publishing the new checkpoint which is used for remote store + segrep indexes
+        checkpointPublisher.publish(indexShard, checkpoint);
+        logger.debug("onSuccessfulSegmentsSync lastRefreshedCheckpoint={} checkpoint={}", lastRefreshedCheckpoint, checkpoint);
+    }
+
+    /**
+     * Resets the backoff delay iterator so that the next set of failures starts with the base delay and goes upto max delay.
+     */
+    private void resetBackOffDelayIterator() {
+        backoffDelayIterator = EXPONENTIAL_BACKOFF_POLICY.iterator();
+    }
+
+    @Override
+    protected TimeValue getNextRetryInterval() {
+        return backoffDelayIterator.next();
+    }
+
+    @Override
+    protected String getRetryThreadPoolName() {
+        return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+    }
+
+    private boolean isRefreshAfterCommit() throws IOException {
+        String lastCommittedLocalSegmentFileName = SegmentInfos.getLastCommitSegmentsFileName(storeDirectory);
+        return (lastCommittedLocalSegmentFileName != null
+            && !remoteDirectory.containsFile(lastCommittedLocalSegmentFileName, getChecksumOfLocalFile(lastCommittedLocalSegmentFileName)));
+    }
+
+    void uploadMetadata(Collection<String> localSegmentsPostRefresh, SegmentInfos segmentInfos, ReplicationCheckpoint replicationCheckpoint)
+        throws IOException {
+        final long maxSeqNo = ((InternalEngine) indexShard.getEngine()).currentOngoingRefreshCheckpoint();
+        SegmentInfos segmentInfosSnapshot = segmentInfos.clone();
+        Map<String, String> userData = segmentInfosSnapshot.getUserData();
+        userData.put(LOCAL_CHECKPOINT_KEY, String.valueOf(maxSeqNo));
+        userData.put(SequenceNumbers.MAX_SEQ_NO, Long.toString(maxSeqNo));
+        segmentInfosSnapshot.setUserData(userData, false);
+
+        Translog.TranslogGeneration translogGeneration = ((InternalEngine) indexShard.getEngine()).translogManager()
+            .getTranslogGeneration();
+        if (translogGeneration == null) {
+            throw new UnsupportedOperationException("Encountered null TranslogGeneration while uploading metadata to remote segment store");
+        } else {
+            long translogFileGeneration = translogGeneration.translogFileGeneration;
+            remoteDirectory.uploadMetadata(
+                localSegmentsPostRefresh,
+                segmentInfosSnapshot,
+                storeDirectory,
+                translogFileGeneration,
+                replicationCheckpoint,
+                indexShard.getNodeId()
+            );
+        }
+    }
+
+    private void uploadNewSegments(Collection<String> localSegmentsPostRefresh, ActionListener<Void> listener) {
+        Collection<String> filteredFiles = localSegmentsPostRefresh.stream().filter(file -> !skipUpload(file)).collect(Collectors.toList());
+        if (filteredFiles.size() == 0) {
+            logger.debug("No new segments to upload in uploadNewSegments");
+            listener.onResponse(null);
+            return;
+        }
+
+        logger.debug("Effective new segments files to upload {}", filteredFiles);
+        ActionListener<Collection<Void>> mappedListener = ActionListener.map(listener, resp -> null);
+        GroupedActionListener<Void> batchUploadListener = new GroupedActionListener<>(mappedListener, filteredFiles.size());
+
+        for (String src : filteredFiles) {
+            // Initializing listener here to ensure that the stats increment operations are thread-safe
+            UploadListener statsListener = createUploadListener();
+            ActionListener<Void> aggregatedListener = ActionListener.wrap(resp -> {
+                statsListener.onSuccess(src);
+                batchUploadListener.onResponse(resp);
+            }, ex -> {
+                logger.warn(() -> new ParameterizedMessage("Exception: [{}] while uploading segment files", ex), ex);
+                if (ex instanceof CorruptIndexException) {
+                    indexShard.failShard(ex.getMessage(), ex);
+                }
+                statsListener.onFailure(src);
+                batchUploadListener.onFailure(ex);
+            });
+            statsListener.beforeUpload(src);
+            remoteDirectory.copyFrom(storeDirectory, src, IOContext.DEFAULT, aggregatedListener);
+        }
+    }
+
+    /**
+     * Whether to upload a file or not depending on whether file is in excluded list or has been already uploaded.
+     *
+     * @param file that needs to be uploaded.
+     * @return true if the upload has to be skipped for the file.
+     */
+    private boolean skipUpload(String file) {
+        try {
+            // Exclude files that are already uploaded and the exclude files to come up with the list of files to be uploaded.
+            return EXCLUDE_FILES.contains(file) || remoteDirectory.containsFile(file, getChecksumOfLocalFile(file));
+        } catch (IOException e) {
+            logger.error(
+                "Exception while reading checksum of local segment file: {}, ignoring the exception and re-uploading the file",
+                file
+            );
+        }
+        return false;
+    }
+
+    private String getChecksumOfLocalFile(String file) throws IOException {
+        if (!localSegmentChecksumMap.containsKey(file)) {
+            try (IndexInput indexInput = storeDirectory.openInput(file, IOContext.DEFAULT)) {
+                String checksum = Long.toString(CodecUtil.retrieveChecksum(indexInput));
+                localSegmentChecksumMap.put(file, checksum);
+            }
+        }
+        return localSegmentChecksumMap.get(file);
+    }
+
+    /**
+     * Updates the last refresh time and refresh seq no which is seen by remote store.
+     */
+    private void updateRemoteRefreshTimeAndSeqNo(long refreshTimeMs, long refreshClockTimeMs, long refreshSeqNo) {
+        segmentTracker.updateRemoteRefreshClockTimeMs(refreshClockTimeMs);
+        segmentTracker.updateRemoteRefreshTimeMs(refreshTimeMs);
+        segmentTracker.updateRemoteRefreshSeqNo(refreshSeqNo);
+    }
+
+    /**
+     * Updates map of file name to size of the input segment files in the segment tracker. Uses {@code storeDirectory.fileLength(file)} to get the size.
+     *
+     * @param segmentFiles list of segment files that are part of the most recent local refresh.
+     */
+    private void updateLocalSizeMapAndTracker(Collection<String> segmentFiles) {
+        segmentTracker.updateLatestLocalFileNameLengthMap(segmentFiles, storeDirectory::fileLength);
+    }
+
+    private void updateFinalStatusInSegmentTracker(boolean uploadStatus, long bytesBeforeUpload, long startTimeInNS) {
+        if (uploadStatus) {
+            long bytesUploaded = segmentTracker.getUploadBytesSucceeded() - bytesBeforeUpload;
+            long timeTakenInMS = TimeValue.nsecToMSec(System.nanoTime() - startTimeInNS);
+            segmentTracker.incrementTotalUploadsSucceeded();
+            segmentTracker.updateUploadBytesMovingAverage(bytesUploaded);
+            segmentTracker.updateUploadBytesPerSecMovingAverage((bytesUploaded * 1_000L) / Math.max(1, timeTakenInMS));
+            segmentTracker.updateUploadTimeMovingAverage(timeTakenInMS);
+        } else {
+            segmentTracker.incrementTotalUploadsFailed();
+        }
+    }
+
+    /**
+     * Creates an {@link UploadListener} containing the stats population logic which would be triggered before and after segment upload events
+     */
+    private UploadListener createUploadListener() {
+        return new UploadListener() {
+            private long uploadStartTime = 0;
+
+            @Override
+            public void beforeUpload(String file) {
+                // Start tracking the upload bytes started
+                segmentTracker.addUploadBytesStarted(segmentTracker.getLatestLocalFileNameLengthMap().get(file));
+                uploadStartTime = System.currentTimeMillis();
+            }
+
+            @Override
+            public void onSuccess(String file) {
+                // Track upload success
+                segmentTracker.addUploadBytesSucceeded(segmentTracker.getLatestLocalFileNameLengthMap().get(file));
+                segmentTracker.addToLatestUploadedFiles(file);
+                segmentTracker.addUploadTimeInMillis(Math.max(1, System.currentTimeMillis() - uploadStartTime));
+            }
+
+            @Override
+            public void onFailure(String file) {
+                // Track upload failure
+                segmentTracker.addUploadBytesFailed(segmentTracker.getLatestLocalFileNameLengthMap().get(file));
+                segmentTracker.addUploadTimeInMillis(Math.max(1, System.currentTimeMillis() - uploadStartTime));
+            }
+        };
+    }
+
+    @Override
+    protected Logger getLogger() {
+        return logger;
+    }
+
+    @Override
+    protected boolean isRetryEnabled() {
+        return true;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedLuceneSegmentsAction.java b/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedLuceneSegmentsAction.java
index 621f1fcec28f2..93ef2c4abf09d 100644
--- a/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedLuceneSegmentsAction.java
+++ b/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedLuceneSegmentsAction.java
@@ -43,6 +43,8 @@
 
 /**
  * Removes corrupted Lucene index segments
+ *
+ * @opensearch.internal
  */
 public class RemoveCorruptedLuceneSegmentsAction {
 
diff --git a/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommand.java b/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommand.java
index a6ecc803affbb..a56d61194bf45 100644
--- a/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommand.java
+++ b/server/src/main/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommand.java
@@ -54,18 +54,20 @@
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
 import org.opensearch.gateway.PersistedClusterStateService;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.SequenceNumbers;
@@ -84,6 +86,11 @@
 import java.util.Objects;
 import java.util.stream.StreamSupport;
 
+/**
+ * Command for removing a corruped shard
+ *
+ * @opensearch.internal
+ */
 public class RemoveCorruptedShardDataCommand extends OpenSearchNodeCommand {
 
     private static final Logger logger = LogManager.getLogger(RemoveCorruptedShardDataCommand.class);
@@ -138,8 +145,6 @@ protected void findAndProcessShardPath(
 
         final IndexMetadata indexMetadata;
         final int shardId;
-        final int fromNodeId;
-        final int toNodeId;
 
         if (options.has(folderOption)) {
             final Path path = getPath(folderOption.value(options)).getParent();
@@ -160,10 +165,7 @@ protected void findAndProcessShardPath(
                 && NodeEnvironment.NODES_FOLDER.equals(shardParentParent.getParent().getParent().getFileName().toString()) // `nodes` check
             ) {
                 shardId = Integer.parseInt(shardIdFileName);
-                fromNodeId = Integer.parseInt(nodeIdFileName);
-                toNodeId = fromNodeId + 1;
                 indexMetadata = StreamSupport.stream(clusterState.metadata().indices().values().spliterator(), false)
-                    .map(imd -> imd.value)
                     .filter(imd -> imd.getIndexUUID().equals(indexUUIDFolderName))
                     .findFirst()
                     .orElse(null);
@@ -186,6 +188,11 @@ protected void findAndProcessShardPath(
         }
 
         final IndexSettings indexSettings = new IndexSettings(indexMetadata, settings);
+        if (indexSettings.isRemoteTranslogStoreEnabled()) {
+            // ToDo : Need to revisit corrupt shard recovery strategy for remote store enabled indices
+            throw new OpenSearchException("tool doesn't work for remote translog enabled indices");
+        }
+
         final Index index = indexMetadata.getIndex();
         final ShardId shId = new ShardId(index, shardId);
 
@@ -238,11 +245,9 @@ protected void dropCorruptMarkerFiles(Terminal terminal, Path path, Directory di
             );
         }
         String[] files = directory.listAll();
-        boolean found = false;
         for (String file : files) {
             if (file.startsWith(Store.CORRUPTED_MARKER_NAME_PREFIX)) {
                 directory.deleteFile(file);
-
                 terminal.println("Deleted corrupt marker " + file + " from " + path);
             }
         }
@@ -479,7 +484,8 @@ private void newAllocationId(ShardPath shardPath, Terminal terminal) throws IOEx
         final ShardStateMetadata newShardStateMetadata = new ShardStateMetadata(
             shardStateMetadata.primary,
             shardStateMetadata.indexUUID,
-            newAllocationId
+            newAllocationId,
+            ShardStateMetadata.IndexDataLocation.LOCAL
         );
 
         ShardStateMetadata.FORMAT.writeAndCleanup(newShardStateMetadata, shardStatePath);
@@ -508,7 +514,7 @@ private void printRerouteCommand(ShardPath shardPath, Terminal terminal, boolean
         );
 
         terminal.println("");
-        terminal.println("POST /_cluster/reroute\n" + Strings.toString(commands, true, true));
+        terminal.println("POST /_cluster/reroute\n" + Strings.toString(MediaTypeRegistry.JSON, commands, true, true));
         terminal.println("");
         terminal.println("You must accept the possibility of data loss by changing the `accept_data_loss` parameter to `true`.");
         terminal.println("");
@@ -523,6 +529,11 @@ private Path getNodePath(ShardPath shardPath) {
         return nodePath;
     }
 
+    /**
+     * Status of the shard cleaning operation
+     *
+     * @opensearch.internal
+     */
     public enum CleanStatus {
         CLEAN("clean"),
         CLEAN_WITH_CORRUPTED_MARKER("marked corrupted, but no corruption detected"),
diff --git a/server/src/main/java/org/opensearch/index/shard/ReplicationGroup.java b/server/src/main/java/org/opensearch/index/shard/ReplicationGroup.java
index fc52d09361281..6d19e9f500411 100644
--- a/server/src/main/java/org/opensearch/index/shard/ReplicationGroup.java
+++ b/server/src/main/java/org/opensearch/index/shard/ReplicationGroup.java
@@ -42,6 +42,8 @@
 
 /**
  * Replication group for a shard. Used by a primary shard to coordinate replication and recoveries.
+ *
+ * @opensearch.internal
  */
 public class ReplicationGroup {
     private final IndexShardRoutingTable routingTable;
diff --git a/server/src/main/java/org/opensearch/index/shard/SearchOperationListener.java b/server/src/main/java/org/opensearch/index/shard/SearchOperationListener.java
index da4b3a141dfc5..e9206731058db 100644
--- a/server/src/main/java/org/opensearch/index/shard/SearchOperationListener.java
+++ b/server/src/main/java/org/opensearch/index/shard/SearchOperationListener.java
@@ -33,7 +33,6 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.search.internal.ReaderContext;
 import org.opensearch.search.internal.SearchContext;
@@ -43,6 +42,8 @@
 
 /**
  * An listener for search, fetch and context events.
+ *
+ * @opensearch.internal
  */
 public interface SearchOperationListener {
 
@@ -129,6 +130,19 @@ default void onFreeScrollContext(ReaderContext readerContext) {}
      */
     default void validateReaderContext(ReaderContext readerContext, TransportRequest transportRequest) {}
 
+    /**
+     * Executed when a new Point-In-Time {@link ReaderContext} was created
+     * @param readerContext the created reader context
+     */
+    default void onNewPitContext(ReaderContext readerContext) {}
+
+    /**
+     * Executed when a Point-In-Time search {@link SearchContext} is freed.
+     * This happens on deletion of a Point-In-Time or on it's keep-alive is expiring.
+     * @param readerContext the freed search context
+     */
+    default void onFreePitContext(ReaderContext readerContext) {}
+
     /**
      * A Composite listener that multiplexes calls to each of the listeners methods.
      */
@@ -263,5 +277,36 @@ public void validateReaderContext(ReaderContext readerContext, TransportRequest
             }
             ExceptionsHelper.reThrowIfNotNull(exception);
         }
+
+        /**
+         * Executed when a new Point-In-Time {@link ReaderContext} was created
+         * @param readerContext the created reader context
+         */
+        @Override
+        public void onNewPitContext(ReaderContext readerContext) {
+            for (SearchOperationListener listener : listeners) {
+                try {
+                    listener.onNewPitContext(readerContext);
+                } catch (Exception e) {
+                    logger.warn("onNewPitContext listener failed", e);
+                }
+            }
+        }
+
+        /**
+         * Executed when a Point-In-Time search {@link SearchContext} is freed.
+         * This happens on deletion of a Point-In-Time or on it's keep-alive is expiring.
+         * @param readerContext the freed search context
+         */
+        @Override
+        public void onFreePitContext(ReaderContext readerContext) {
+            for (SearchOperationListener listener : listeners) {
+                try {
+                    listener.onFreePitContext(readerContext);
+                } catch (Exception e) {
+                    logger.warn("onFreePitContext listener failed", e);
+                }
+            }
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardId.java b/server/src/main/java/org/opensearch/index/shard/ShardId.java
deleted file mode 100644
index a4ff927c5a5dc..0000000000000
--- a/server/src/main/java/org/opensearch/index/shard/ShardId.java
+++ /dev/null
@@ -1,148 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.shard;
-
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
-
-import java.io.IOException;
-
-/**
- * Allows for shard level components to be injected with the shard id.
- */
-public class ShardId implements Comparable<ShardId>, ToXContentFragment, Writeable {
-
-    private final Index index;
-    private final int shardId;
-    private final int hashCode;
-
-    public ShardId(Index index, int shardId) {
-        this.index = index;
-        this.shardId = shardId;
-        this.hashCode = computeHashCode();
-    }
-
-    public ShardId(String index, String indexUUID, int shardId) {
-        this(new Index(index, indexUUID), shardId);
-    }
-
-    public ShardId(StreamInput in) throws IOException {
-        index = new Index(in);
-        shardId = in.readVInt();
-        hashCode = computeHashCode();
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        index.writeTo(out);
-        out.writeVInt(shardId);
-    }
-
-    public Index getIndex() {
-        return index;
-    }
-
-    public String getIndexName() {
-        return index.getName();
-    }
-
-    public int id() {
-        return this.shardId;
-    }
-
-    public int getId() {
-        return id();
-    }
-
-    @Override
-    public String toString() {
-        return "[" + index.getName() + "][" + shardId + "]";
-    }
-
-    /**
-     * Parse the string representation of this shardId back to an object.
-     * We lose index uuid information here, but since we use toString in
-     * rest responses, this is the best we can do to reconstruct the object
-     * on the client side.
-     */
-    public static ShardId fromString(String shardIdString) {
-        int splitPosition = shardIdString.indexOf("][");
-        if (splitPosition <= 0 || shardIdString.charAt(0) != '[' || shardIdString.charAt(shardIdString.length() - 1) != ']') {
-            throw new IllegalArgumentException("Unexpected shardId string format, expected [indexName][shardId] but got " + shardIdString);
-        }
-        String indexName = shardIdString.substring(1, splitPosition);
-        int shardId = Integer.parseInt(shardIdString.substring(splitPosition + 2, shardIdString.length() - 1));
-        return new ShardId(new Index(indexName, IndexMetadata.INDEX_UUID_NA_VALUE), shardId);
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-        ShardId shardId1 = (ShardId) o;
-        return shardId == shardId1.shardId && index.equals(shardId1.index);
-    }
-
-    @Override
-    public int hashCode() {
-        return hashCode;
-    }
-
-    private int computeHashCode() {
-        int result = index != null ? index.hashCode() : 0;
-        result = 31 * result + shardId;
-        return result;
-    }
-
-    @Override
-    public int compareTo(ShardId o) {
-        if (o.getId() == shardId) {
-            int compare = index.getName().compareTo(o.getIndex().getName());
-            if (compare != 0) {
-                return compare;
-            }
-            return index.getUUID().compareTo(o.getIndex().getUUID());
-        }
-        return Integer.compare(shardId, o.getId());
-    }
-
-    @Override
-    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        return builder.value(toString());
-    }
-}
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardNotFoundException.java b/server/src/main/java/org/opensearch/index/shard/ShardNotFoundException.java
index 8346b841007d9..c68c89b96cb4f 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardNotFoundException.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardNotFoundException.java
@@ -33,10 +33,16 @@
 package org.opensearch.index.shard;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a shard is not found
+ *
+ * @opensearch.internal
+ */
 public class ShardNotFoundException extends ResourceNotFoundException {
     public ShardNotFoundException(ShardId shardId) {
         this(shardId, null);
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardNotInPrimaryModeException.java b/server/src/main/java/org/opensearch/index/shard/ShardNotInPrimaryModeException.java
index a82f1ba5c77d0..412dee8a7abcf 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardNotInPrimaryModeException.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardNotInPrimaryModeException.java
@@ -32,10 +32,16 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a shard is not in primary mode
+ *
+ * @opensearch.internal
+ */
 public class ShardNotInPrimaryModeException extends IllegalIndexShardStateException {
 
     public ShardNotInPrimaryModeException(final ShardId shardId, final IndexShardState currentState) {
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardPath.java b/server/src/main/java/org/opensearch/index/shard/ShardPath.java
index 39f86ea362bb1..b7bb4283eca32 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardPath.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardPath.java
@@ -33,9 +33,10 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.util.Strings;
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
 import org.opensearch.index.IndexSettings;
@@ -50,6 +51,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Path for a shard
+ *
+ * @opensearch.internal
+ */
 public final class ShardPath {
     public static final String INDEX_FOLDER_NAME = "index";
     public static final String TRANSLOG_FOLDER_NAME = "translog";
@@ -125,6 +131,16 @@ public boolean isCustomDataPath() {
         return isCustomDataPath;
     }
 
+    /**
+     * Returns the shard path to be stored within the cache on the search capable node.
+     */
+    public static ShardPath loadFileCachePath(NodeEnvironment env, ShardId shardId) {
+        NodeEnvironment.NodePath path = env.fileCacheNodePath();
+        final Path dataPath = env.resolveFileCacheLocation(path.fileCachePath, shardId);
+        final Path statePath = path.resolve(shardId);
+        return new ShardPath(true, dataPath, statePath, shardId);
+    }
+
     /**
      * This method walks through the nodes shard paths to find the data and state path for the given shard. If multiple
      * directories with a valid shard state exist the one with the highest version will be used.
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardSplittingQuery.java b/server/src/main/java/org/opensearch/index/shard/ShardSplittingQuery.java
index 16d76ece840a2..219ead931797a 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardSplittingQuery.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardSplittingQuery.java
@@ -72,6 +72,8 @@
  * A query that selects all docs that do NOT belong in the current shards this query is executed on.
  * It can be used to split a shard into N shards marking every document that doesn't belong into the shard
  * as deleted. See {@link org.apache.lucene.index.IndexWriter#deleteDocuments(Query...)}
+ *
+ * @opensearch.internal
  */
 final class ShardSplittingQuery extends Query {
     private final IndexMetadata indexMetadata;
@@ -284,7 +286,7 @@ public Status needsField(FieldInfo fieldInfo) throws IOException {
         boolean matches(int doc) throws IOException {
             routing = id = null;
             leftToVisit = 2;
-            leafReader.document(doc, this);
+            leafReader.storedFields().document(doc, this);
             assert id != null : "docID must not be null - we might have hit a nested document";
             int targetShardId = OperationRouting.generateShardId(indexMetadata, id, routing);
             return targetShardId != shardId;
@@ -294,6 +296,8 @@ boolean matches(int doc) throws IOException {
     /**
      * This two phase iterator visits every live doc and selects all docs that don't belong into this
      * shard based on their id and routing value. This is only used in a routing partitioned index.
+     *
+     * @opensearch.internal
      */
     private static final class RoutingPartitionedDocIdSetIterator extends TwoPhaseIterator {
         private final Visitor visitor;
@@ -316,6 +320,8 @@ public float matchCost() {
 
     /**
      * This TwoPhaseIterator marks all nested docs of matching parents as matches as well.
+     *
+     * @opensearch.internal
      */
     private static final class NestedRoutingPartitionedDocIdSetIterator extends TwoPhaseIterator {
         private final Visitor visitor;
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardStateMetadata.java b/server/src/main/java/org/opensearch/index/shard/ShardStateMetadata.java
index 194c1e58277a8..9c0134fa79551 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardStateMetadata.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardStateMetadata.java
@@ -35,9 +35,9 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.CorruptStateException;
 import org.opensearch.gateway.MetadataStateFormat;
 
@@ -45,23 +45,50 @@
 import java.io.OutputStream;
 import java.util.Objects;
 
+/**
+ * Metadata string a shard state
+ *
+ * @opensearch.internal
+ */
 public final class ShardStateMetadata {
 
     private static final String SHARD_STATE_FILE_PREFIX = "state-";
     private static final String PRIMARY_KEY = "primary";
     private static final String INDEX_UUID_KEY = "index_uuid";
     private static final String ALLOCATION_ID_KEY = "allocation_id";
+    private static final String INDEX_DATA_LOCATION_KEY = "index_data_location";
+
+    /**
+     * Enumeration of types of data locations for an index
+     */
+    public enum IndexDataLocation {
+        /**
+         * Indicates index data is on the local disk
+         */
+        LOCAL,
+        /**
+         * Indicates index data is remote, such as for a searchable snapshot
+         * index
+         */
+        REMOTE
+    }
 
     public final String indexUUID;
     public final boolean primary;
     @Nullable
     public final AllocationId allocationId; // can be null if we read from legacy format (see fromXContent and MultiDataPathUpgrader)
+    public final IndexDataLocation indexDataLocation;
 
     public ShardStateMetadata(boolean primary, String indexUUID, AllocationId allocationId) {
+        this(primary, indexUUID, allocationId, IndexDataLocation.LOCAL);
+    }
+
+    public ShardStateMetadata(boolean primary, String indexUUID, AllocationId allocationId, IndexDataLocation indexDataLocation) {
         assert indexUUID != null;
         this.primary = primary;
         this.indexUUID = indexUUID;
         this.allocationId = allocationId;
+        this.indexDataLocation = Objects.requireNonNull(indexDataLocation);
     }
 
     @Override
@@ -84,6 +111,9 @@ public boolean equals(Object o) {
         if (Objects.equals(allocationId, that.allocationId) == false) {
             return false;
         }
+        if (Objects.equals(indexDataLocation, that.indexDataLocation) == false) {
+            return false;
+        }
 
         return true;
     }
@@ -93,17 +123,16 @@ public int hashCode() {
         int result = indexUUID.hashCode();
         result = 31 * result + (allocationId != null ? allocationId.hashCode() : 0);
         result = 31 * result + (primary ? 1 : 0);
+        result = 31 * result + indexDataLocation.hashCode();
         return result;
     }
 
     @Override
     public String toString() {
-        return "primary [" + primary + "], allocation [" + allocationId + "]";
+        return "primary [" + primary + "], allocation [" + allocationId + "], index data location [" + indexDataLocation + "]";
     }
 
-    public static final MetadataStateFormat<ShardStateMetadata> FORMAT = new MetadataStateFormat<ShardStateMetadata>(
-        SHARD_STATE_FILE_PREFIX
-    ) {
+    public static final MetadataStateFormat<ShardStateMetadata> FORMAT = new MetadataStateFormat<>(SHARD_STATE_FILE_PREFIX) {
 
         @Override
         protected XContentBuilder newXContentBuilder(XContentType type, OutputStream stream) throws IOException {
@@ -119,6 +148,11 @@ public void toXContent(XContentBuilder builder, ShardStateMetadata shardStateMet
             if (shardStateMetadata.allocationId != null) {
                 builder.field(ALLOCATION_ID_KEY, shardStateMetadata.allocationId);
             }
+            // Omit the index data location field if it is LOCAL (the implicit default)
+            // to maintain compatibility for local indices
+            if (shardStateMetadata.indexDataLocation != IndexDataLocation.LOCAL) {
+                builder.field(INDEX_DATA_LOCATION_KEY, shardStateMetadata.indexDataLocation);
+            }
         }
 
         @Override
@@ -131,6 +165,7 @@ public ShardStateMetadata fromXContent(XContentParser parser) throws IOException
             String currentFieldName = null;
             String indexUUID = IndexMetadata.INDEX_UUID_NA_VALUE;
             AllocationId allocationId = null;
+            IndexDataLocation indexDataLocation = IndexDataLocation.LOCAL;
             while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                 if (token == XContentParser.Token.FIELD_NAME) {
                     currentFieldName = parser.currentName();
@@ -139,6 +174,13 @@ public ShardStateMetadata fromXContent(XContentParser parser) throws IOException
                         primary = parser.booleanValue();
                     } else if (INDEX_UUID_KEY.equals(currentFieldName)) {
                         indexUUID = parser.text();
+                    } else if (INDEX_DATA_LOCATION_KEY.equals(currentFieldName)) {
+                        final String stringValue = parser.text();
+                        try {
+                            indexDataLocation = IndexDataLocation.valueOf(stringValue);
+                        } catch (IllegalArgumentException e) {
+                            throw new CorruptStateException("unexpected value for data location [" + stringValue + "]");
+                        }
                     } else {
                         throw new CorruptStateException("unexpected field in shard state [" + currentFieldName + "]");
                     }
@@ -155,7 +197,7 @@ public ShardStateMetadata fromXContent(XContentParser parser) throws IOException
             if (primary == null) {
                 throw new CorruptStateException("missing value for [primary] in shard state");
             }
-            return new ShardStateMetadata(primary, indexUUID, allocationId);
+            return new ShardStateMetadata(primary, indexUUID, allocationId, indexDataLocation);
         }
     };
 }
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardToolCli.java b/server/src/main/java/org/opensearch/index/shard/ShardToolCli.java
index 0234e85fbf0db..1b4eb5a3f8c39 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardToolCli.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardToolCli.java
@@ -36,6 +36,8 @@
 
 /**
  * Class encapsulating and dispatching commands from the {@code opensearch-shard} command line tool
+ *
+ * @opensearch.internal
  */
 public class ShardToolCli extends LoggingAwareMultiCommand {
 
diff --git a/server/src/main/java/org/opensearch/index/shard/ShardUtils.java b/server/src/main/java/org/opensearch/index/shard/ShardUtils.java
index a9cbd2c3f23f9..8e5688b26f93d 100644
--- a/server/src/main/java/org/opensearch/index/shard/ShardUtils.java
+++ b/server/src/main/java/org/opensearch/index/shard/ShardUtils.java
@@ -37,7 +37,13 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.lucene.index.OpenSearchLeafReader;
+import org.opensearch.core.index.shard.ShardId;
 
+/**
+ * Utility class for shard operations
+ *
+ * @opensearch.internal
+ */
 public final class ShardUtils {
 
     private ShardUtils() {}
diff --git a/server/src/main/java/org/opensearch/index/shard/StoreRecovery.java b/server/src/main/java/org/opensearch/index/shard/StoreRecovery.java
index 387f77a839d35..762aab51469d0 100644
--- a/server/src/main/java/org/opensearch/index/shard/StoreRecovery.java
+++ b/server/src/main/java/org/opensearch/index/shard/StoreRecovery.java
@@ -43,7 +43,6 @@
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
@@ -51,21 +50,32 @@
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.snapshots.IndexShardRestoreFailedException;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.Checkpoint;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.TranslogHeader;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.Repository;
 
 import java.io.IOException;
+import java.nio.channels.FileChannel;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
@@ -75,10 +85,13 @@
 import java.util.stream.Collectors;
 
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
+import static org.opensearch.index.translog.Translog.CHECKPOINT_FILE_NAME;
 
 /**
  * This package private utility class encapsulates the logic to recover an index shard from either an existing index on
  * disk or from a snapshot in a repository.
+ *
+ * @opensearch.internal
  */
 final class StoreRecovery {
 
@@ -101,9 +114,6 @@ final class StoreRecovery {
      */
     void recoverFromStore(final IndexShard indexShard, ActionListener<Boolean> listener) {
         if (canRecover(indexShard)) {
-            RecoverySource.Type recoveryType = indexShard.recoveryState().getRecoverySource().getType();
-            assert recoveryType == RecoverySource.Type.EMPTY_STORE || recoveryType == RecoverySource.Type.EXISTING_STORE
-                : "expected store recovery type but was: " + recoveryType;
             ActionListener.completeWith(recoveryListener(indexShard, listener), () -> {
                 logger.debug("starting recovery from store ...");
                 internalRecoverFromStore(indexShard);
@@ -114,6 +124,20 @@ void recoverFromStore(final IndexShard indexShard, ActionListener<Boolean> liste
         }
     }
 
+    void recoverFromRemoteStore(final IndexShard indexShard, ActionListener<Boolean> listener) {
+        if (canRecover(indexShard)) {
+            RecoverySource.Type recoveryType = indexShard.recoveryState().getRecoverySource().getType();
+            assert recoveryType == RecoverySource.Type.REMOTE_STORE : "expected remote store recovery type but was: " + recoveryType;
+            ActionListener.completeWith(recoveryListener(indexShard, listener), () -> {
+                logger.debug("starting recovery from remote store ...");
+                recoverFromRemoteStore(indexShard);
+                return true;
+            });
+        } else {
+            listener.onResponse(false);
+        }
+    }
+
     void recoverFromLocalShards(
         Consumer<MappingMetadata> mappingUpdateConsumer,
         IndexShard indexShard,
@@ -176,7 +200,7 @@ void recoverFromLocalShards(
     }
 
     void addIndices(
-        final RecoveryState.Index indexRecoveryStats,
+        final ReplicationLuceneIndex indexRecoveryStats,
         final Directory target,
         final Sort indexSort,
         final Directory[] sources,
@@ -229,11 +253,13 @@ void addIndices(
 
     /**
      * Directory wrapper that records copy process for recovery statistics
+     *
+     * @opensearch.internal
      */
     static final class StatsDirectoryWrapper extends FilterDirectory {
-        private final RecoveryState.Index index;
+        private final ReplicationLuceneIndex index;
 
-        StatsDirectoryWrapper(Directory in, RecoveryState.Index indexRecoveryStats) {
+        StatsDirectoryWrapper(Directory in, ReplicationLuceneIndex indexRecoveryStats) {
             super(in);
             this.index = indexRecoveryStats;
         }
@@ -248,7 +274,9 @@ public void copyFrom(Directory from, String src, String dest, IOContext context)
             in.copyFrom(new FilterDirectory(from) {
                 @Override
                 public IndexInput openInput(String name, IOContext context) throws IOException {
-                    index.addFileDetail(dest, l, false);
+                    if (index.getFileDetails(dest) == null) {
+                        index.addFileDetail(dest, l, false);
+                    }
                     copies.set(true);
                     final IndexInput input = in.openInput(name, context);
                     return new IndexInput("StatsDirectoryWrapper(" + input.toString() + ")") {
@@ -291,7 +319,7 @@ public void readBytes(byte[] b, int offset, int len) throws IOException {
                     };
                 }
             }, src, dest, context);
-            if (copies.get() == false) {
+            if (copies.get() == false && index.getFileDetails(dest) == null) {
                 index.addFileDetail(dest, l, true); // hardlinked - we treat it as reused since the file was already somewhat there
             } else {
                 assert index.getFileDetails(dest) != null : "File [" + dest + "] has no file details";
@@ -329,6 +357,71 @@ void recoverFromRepository(final IndexShard indexShard, Repository repository, A
         }
     }
 
+    void recoverFromSnapshotAndRemoteStore(
+        final IndexShard indexShard,
+        Repository repository,
+        RemoteSegmentStoreDirectoryFactory directoryFactory,
+        ActionListener<Boolean> listener
+    ) {
+        try {
+            if (canRecover(indexShard)) {
+                indexShard.preRecovery();
+                RecoverySource.Type recoveryType = indexShard.recoveryState().getRecoverySource().getType();
+                assert recoveryType == RecoverySource.Type.SNAPSHOT : "expected snapshot recovery type: " + recoveryType;
+                SnapshotRecoverySource recoverySource = (SnapshotRecoverySource) indexShard.recoveryState().getRecoverySource();
+                final RecoveryState.Translog translogState = indexShard.recoveryState().getTranslog();
+                translogState.totalOperations(0);
+                translogState.totalOperationsOnStart(0);
+                indexShard.prepareForIndexRecovery();
+
+                RemoteStoreShardShallowCopySnapshot shallowCopyShardMetadata = repository.getRemoteStoreShallowCopyShardMetadata(
+                    recoverySource.snapshot().getSnapshotId(),
+                    recoverySource.index(),
+                    shardId
+                );
+
+                long primaryTerm = shallowCopyShardMetadata.getPrimaryTerm();
+                long commitGeneration = shallowCopyShardMetadata.getCommitGeneration();
+                String indexUUID = shallowCopyShardMetadata.getIndexUUID();
+                String remoteStoreRepository = ((SnapshotRecoverySource) indexShard.recoveryState().getRecoverySource())
+                    .sourceRemoteStoreRepository();
+                if (remoteStoreRepository == null) {
+                    remoteStoreRepository = shallowCopyShardMetadata.getRemoteStoreRepository();
+                }
+
+                RemoteSegmentStoreDirectory sourceRemoteDirectory = (RemoteSegmentStoreDirectory) directoryFactory.newDirectory(
+                    remoteStoreRepository,
+                    indexUUID,
+                    shardId
+                );
+                indexShard.syncSegmentsFromGivenRemoteSegmentStore(true, sourceRemoteDirectory, primaryTerm, commitGeneration);
+                final Store store = indexShard.store();
+                if (indexShard.indexSettings.isRemoteTranslogStoreEnabled() == false) {
+                    bootstrap(indexShard, store);
+                } else {
+                    bootstrapForSnapshot(indexShard, store);
+                }
+                assert indexShard.shardRouting.primary() : "only primary shards can recover from store";
+                writeEmptyRetentionLeasesFile(indexShard);
+                indexShard.recoveryState().getIndex().setFileDetailsComplete();
+                if (indexShard.indexSettings.isRemoteStoreEnabled()) {
+                    indexShard.openEngineAndSkipTranslogRecoveryFromSnapshot();
+                } else {
+                    indexShard.openEngineAndRecoverFromTranslog();
+                }
+                indexShard.getEngine().fillSeqNoGaps(indexShard.getPendingPrimaryTerm());
+                indexShard.finalizeRecovery();
+                indexShard.postRecovery("restore done");
+
+                listener.onResponse(true);
+            } else {
+                listener.onResponse(false);
+            }
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
     private boolean canRecover(IndexShard indexShard) {
         if (indexShard.state() == IndexShardState.CLOSED) {
             // got closed on us, just ignore this recovery
@@ -354,7 +447,7 @@ private ActionListener<Boolean> recoveryListener(IndexShard indexShard, ActionLi
                     + "]";
 
                 if (logger.isTraceEnabled()) {
-                    RecoveryState.Index index = recoveryState.getIndex();
+                    ReplicationLuceneIndex index = recoveryState.getIndex();
                     StringBuilder sb = new StringBuilder();
                     sb.append("    index    : files           [")
                         .append(index.totalFileCount())
@@ -419,6 +512,51 @@ private ActionListener<Boolean> recoveryListener(IndexShard indexShard, ActionLi
         });
     }
 
+    private void recoverFromRemoteStore(IndexShard indexShard) throws IndexShardRecoveryException {
+        final Store remoteStore = indexShard.remoteStore();
+        if (remoteStore == null) {
+            throw new IndexShardRecoveryException(
+                indexShard.shardId(),
+                "Remote store is not enabled for this index",
+                new IllegalArgumentException()
+            );
+        }
+        indexShard.preRecovery();
+        indexShard.prepareForIndexRecovery();
+        final Store store = indexShard.store();
+        store.incRef();
+        remoteStore.incRef();
+        try {
+            // Download segments from remote segment store
+            indexShard.syncSegmentsFromRemoteSegmentStore(true);
+            indexShard.syncTranslogFilesFromRemoteTranslog();
+
+            // On index creation, the only segment file that is created is segments_N. We can safely discard this file
+            // as there is no data associated with this shard as part of segments.
+            if (store.directory().listAll().length <= 1) {
+                Path location = indexShard.shardPath().resolveTranslog();
+                Checkpoint checkpoint = Checkpoint.read(location.resolve(CHECKPOINT_FILE_NAME));
+                final Path translogFile = location.resolve(Translog.getFilename(checkpoint.getGeneration()));
+                try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
+                    TranslogHeader translogHeader = TranslogHeader.read(translogFile, channel);
+                    store.createEmpty(indexShard.indexSettings().getIndexVersionCreated().luceneVersion, translogHeader.getTranslogUUID());
+                }
+            }
+
+            assert indexShard.shardRouting.primary() : "only primary shards can recover from store";
+            indexShard.recoveryState().getIndex().setFileDetailsComplete();
+            indexShard.openEngineAndRecoverFromTranslog();
+            indexShard.getEngine().fillSeqNoGaps(indexShard.getPendingPrimaryTerm());
+            indexShard.finalizeRecovery();
+            indexShard.postRecovery("post recovery from remote_store");
+        } catch (IOException | IndexShardRecoveryException e) {
+            throw new IndexShardRecoveryException(indexShard.shardId, "Exception while recovering from remote store", e);
+        } finally {
+            store.decRef();
+            remoteStore.decRef();
+        }
+    }
+
     /**
      * Recovers the state of the shard from the store.
      */
@@ -471,7 +609,7 @@ private void internalRecoverFromStore(IndexShard indexShard) throws IndexShardRe
                     writeEmptyRetentionLeasesFile(indexShard);
                 }
                 // since we recover from local, just fill the files and size
-                final RecoveryState.Index index = recoveryState.getIndex();
+                final ReplicationLuceneIndex index = recoveryState.getIndex();
                 try {
                     if (si != null) {
                         addRecoveredFileDetails(si, store, index);
@@ -509,7 +647,7 @@ private static void writeEmptyRetentionLeasesFile(IndexShard indexShard) throws
         assert indexShard.loadRetentionLeases().leases().isEmpty();
     }
 
-    private void addRecoveredFileDetails(SegmentInfos si, Store store, RecoveryState.Index index) throws IOException {
+    private void addRecoveredFileDetails(SegmentInfos si, Store store, ReplicationLuceneIndex index) throws IOException {
         final Directory directory = store.directory();
         for (String name : Lucene.files(si)) {
             long length = directory.fileLength(name);
@@ -538,10 +676,18 @@ private void restore(
         }
         final ActionListener<Void> restoreListener = ActionListener.wrap(v -> {
             final Store store = indexShard.store();
-            bootstrap(indexShard, store);
+            if (indexShard.indexSettings.isRemoteTranslogStoreEnabled() == false) {
+                bootstrap(indexShard, store);
+            } else {
+                bootstrapForSnapshot(indexShard, store);
+            }
             assert indexShard.shardRouting.primary() : "only primary shards can recover from store";
             writeEmptyRetentionLeasesFile(indexShard);
-            indexShard.openEngineAndRecoverFromTranslog();
+            if (indexShard.indexSettings.isRemoteStoreEnabled()) {
+                indexShard.openEngineAndSkipTranslogRecoveryFromSnapshot();
+            } else {
+                indexShard.openEngineAndRecoverFromTranslog();
+            }
             indexShard.getEngine().fillSeqNoGaps(indexShard.getPendingPrimaryTerm());
             indexShard.finalizeRecovery();
             indexShard.postRecovery("restore done");
@@ -561,7 +707,7 @@ private void restore(
             final StepListener<IndexId> indexIdListener = new StepListener<>();
             // If the index UUID was not found in the recovery source we will have to load RepositoryData and resolve it by index name
             if (indexId.getId().equals(IndexMetadata.INDEX_UUID_NA_VALUE)) {
-                // BwC path, running against an old version master that did not add the IndexId to the recovery source
+                // BwC path, running against an old version cluster-manager that did not add the IndexId to the recovery source
                 repository.getRepositoryData(
                     ActionListener.map(indexIdListener, repositoryData -> repositoryData.resolveIndexId(indexId.getName()))
                 );
@@ -585,6 +731,21 @@ private void restore(
         }
     }
 
+    private void bootstrapForSnapshot(final IndexShard indexShard, final Store store) throws IOException {
+        store.bootstrapNewHistory();
+        final SegmentInfos segmentInfos = store.readLastCommittedSegmentsInfo();
+        final long localCheckpoint = Long.parseLong(segmentInfos.userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
+        String translogUUID = store.readLastCommittedSegmentsInfo().getUserData().get(Translog.TRANSLOG_UUID_KEY);
+        Translog.createEmptyTranslog(
+            indexShard.shardPath().resolveTranslog(),
+            shardId,
+            localCheckpoint,
+            indexShard.getPendingPrimaryTerm(),
+            translogUUID,
+            FileChannel::open
+        );
+    }
+
     private void bootstrap(final IndexShard indexShard, final Store store) throws IOException {
         store.bootstrapNewHistory();
         final SegmentInfos segmentInfos = store.readLastCommittedSegmentsInfo();
diff --git a/server/src/main/java/org/opensearch/index/shard/package-info.java b/server/src/main/java/org/opensearch/index/shard/package-info.java
new file mode 100644
index 0000000000000..4b36049f27a55
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/shard/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing classes to implement an Index Shard */
+package org.opensearch.index.shard;
diff --git a/server/src/main/java/org/opensearch/index/similarity/NonNegativeScoresSimilarity.java b/server/src/main/java/org/opensearch/index/similarity/NonNegativeScoresSimilarity.java
index 420f81b755987..9d8be5703a6b7 100644
--- a/server/src/main/java/org/opensearch/index/similarity/NonNegativeScoresSimilarity.java
+++ b/server/src/main/java/org/opensearch/index/similarity/NonNegativeScoresSimilarity.java
@@ -42,6 +42,8 @@
  * A {@link Similarity} that rejects negative scores. This class exists so that users get
  * an error instead of silently corrupt top hits. It should be applied to any custom or
  * scripted similarity.
+ *
+ * @opensearch.internal
  */
 // public for testing
 public final class NonNegativeScoresSimilarity extends Similarity {
diff --git a/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarity.java b/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarity.java
index 27be5658448d1..5b39c03b7276a 100644
--- a/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarity.java
+++ b/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarity.java
@@ -43,6 +43,8 @@
 
 /**
  * A {@link Similarity} implementation that allows scores to be scripted.
+ *
+ * @opensearch.internal
  */
 public final class ScriptedSimilarity extends Similarity {
 
@@ -161,7 +163,11 @@ public Explanation explain(Explanation freq, long norm) {
         }
     }
 
-    /** Scoring factors that come from the query. */
+    /**
+     * Scoring factors that come from the query.
+     *
+     * @opensearch.internal
+     */
     public static class Query {
         private final float boost;
 
@@ -175,7 +181,11 @@ public float getBoost() {
         }
     }
 
-    /** Statistics that are specific to a given field. */
+    /**
+     * Statistics that are specific to a given field.
+     *
+     * @opensearch.internal
+     */
     public static class Field {
         private final long docCount;
         private final long sumDocFreq;
@@ -205,7 +215,11 @@ public long getSumTotalTermFreq() {
         }
     }
 
-    /** Statistics that are specific to a given term. */
+    /**
+     * Statistics that are specific to a given term.
+     *
+     * @opensearch.internal
+     */
     public static class Term {
         private final long docFreq;
         private final long totalTermFreq;
@@ -226,7 +240,11 @@ public long getTotalTermFreq() {
         }
     }
 
-    /** Statistics that are specific to a document. */
+    /**
+     * Statistics that are specific to a document.
+     *
+     * @opensearch.internal
+     */
     public static class Doc {
         private float freq;
         private long norm;
diff --git a/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarityProvider.java b/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarityProvider.java
index c84293d06b0f7..ab1c0341ef3dc 100644
--- a/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarityProvider.java
+++ b/server/src/main/java/org/opensearch/index/similarity/ScriptedSimilarityProvider.java
@@ -41,7 +41,11 @@
 import org.opensearch.script.SimilarityScript;
 import org.opensearch.script.SimilarityWeightScript;
 
-/** Provider of scripted similarities. */
+/**
+ * Provider of scripted similarities.
+ *
+ * @opensearch.internal
+ */
 final class ScriptedSimilarityProvider implements TriFunction<Settings, Version, ScriptService, Similarity> {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/similarity/SimilarityProvider.java b/server/src/main/java/org/opensearch/index/similarity/SimilarityProvider.java
index 9a4444e9ac0f6..ad64f3a55228f 100644
--- a/server/src/main/java/org/opensearch/index/similarity/SimilarityProvider.java
+++ b/server/src/main/java/org/opensearch/index/similarity/SimilarityProvider.java
@@ -38,6 +38,8 @@
 
 /**
  * Wrapper around a {@link Similarity} and its name.
+ *
+ * @opensearch.internal
  */
 public final class SimilarityProvider {
 
diff --git a/server/src/main/java/org/opensearch/index/similarity/SimilarityProviders.java b/server/src/main/java/org/opensearch/index/similarity/SimilarityProviders.java
index 3617c9607a3ab..1e3ec368df411 100644
--- a/server/src/main/java/org/opensearch/index/similarity/SimilarityProviders.java
+++ b/server/src/main/java/org/opensearch/index/similarity/SimilarityProviders.java
@@ -76,6 +76,11 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * A provider for similarity computations
+ *
+ * @opensearch.internal
+ */
 final class SimilarityProviders {
 
     private SimilarityProviders() {} // no instantiation
diff --git a/server/src/main/java/org/opensearch/index/similarity/SimilarityService.java b/server/src/main/java/org/opensearch/index/similarity/SimilarityService.java
index bb82d53de815a..d575ec508acb6 100644
--- a/server/src/main/java/org/opensearch/index/similarity/SimilarityService.java
+++ b/server/src/main/java/org/opensearch/index/similarity/SimilarityService.java
@@ -62,6 +62,11 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
+/**
+ * Service for similarity computations
+ *
+ * @opensearch.internal
+ */
 public final class SimilarityService extends AbstractIndexComponent {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(SimilarityService.class);
     public static final String DEFAULT_SIMILARITY = "BM25";
@@ -203,6 +208,11 @@ Similarity getDefaultSimilarity() {
         return defaultSimilarity;
     }
 
+    /**
+     * Similarity per field
+     *
+     * @opensearch.internal
+     */
     static class PerFieldSimilarity extends PerFieldSimilarityWrapper {
 
         private final Similarity defaultSimilarity;
diff --git a/server/src/main/java/org/opensearch/index/similarity/package-info.java b/server/src/main/java/org/opensearch/index/similarity/package-info.java
new file mode 100644
index 0000000000000..384dcf63f0298
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/similarity/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing the OpenSearch SimilarityService and Providers */
+package org.opensearch.index.similarity;
diff --git a/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreException.java b/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreException.java
index 7dbc3ff60dd74..1cb31f215f4a5 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreException.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreException.java
@@ -33,13 +33,15 @@
 package org.opensearch.index.snapshots;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Generic shard restore exception
+ *
+ * @opensearch.internal
  */
 public class IndexShardRestoreException extends OpenSearchException {
     public IndexShardRestoreException(ShardId shardId, String msg) {
diff --git a/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreFailedException.java b/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreFailedException.java
index 3850f853cc914..50bf5a2e6aeef 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreFailedException.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/IndexShardRestoreFailedException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.index.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
 /**
  * Thrown when restore of a shard fails
+ *
+ * @opensearch.internal
  */
 public class IndexShardRestoreFailedException extends IndexShardRestoreException {
     public IndexShardRestoreFailedException(ShardId shardId, String msg) {
diff --git a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotStatus.java b/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotStatus.java
index fa7da12c18adf..d48da6f462502 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotStatus.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/IndexShardSnapshotStatus.java
@@ -37,11 +37,15 @@
 
 /**
  * Represent shard snapshot status
+ *
+ * @opensearch.internal
  */
 public class IndexShardSnapshotStatus {
 
     /**
      * Snapshot stage
+     *
+     * @opensearch.internal
      */
     public enum Stage {
         /**
@@ -243,6 +247,8 @@ public static IndexShardSnapshotStatus newDone(
 
     /**
      * Returns an immutable state of {@link IndexShardSnapshotStatus} at a given point in time.
+     *
+     * @opensearch.internal
      */
     public static class Copy {
 
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshot.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshot.java
index 516fc19da1c8f..2b718fb055e14 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshot.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshot.java
@@ -35,15 +35,16 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Version;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
+import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.index.store.StoreFileMetadata;
 
 import java.io.IOException;
@@ -54,11 +55,15 @@
 
 /**
  * Shard snapshot metadata
+ *
+ * @opensearch.internal
  */
-public class BlobStoreIndexShardSnapshot implements ToXContentFragment {
+public class BlobStoreIndexShardSnapshot implements ToXContentFragment, IndexShardSnapshot {
 
     /**
      * Information about snapshotted file
+     *
+     * @opensearch.internal
      */
     public static class FileInfo {
 
@@ -588,4 +593,17 @@ public static BlobStoreIndexShardSnapshot fromXContent(XContentParser parser) th
             incrementalSize
         );
     }
+
+    @Override
+    public IndexShardSnapshotStatus getIndexShardSnapshotStatus() {
+        return IndexShardSnapshotStatus.newDone(
+            startTime,
+            time,
+            incrementalFileCount,
+            totalFileCount(),
+            incrementalSize,
+            totalSize(),
+            null
+        ); // Not adding a real generation here as it doesn't matter to callers
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshots.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshots.java
index 87d04e2e01bd2..710f73b3b1fa6 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshots.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/BlobStoreIndexShardSnapshots.java
@@ -33,11 +33,11 @@
 package org.opensearch.index.snapshots.blobstore;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot.FileInfo;
 
 import java.io.IOException;
@@ -55,6 +55,8 @@
  * <p>
  * This class is used to find files that were already snapshotted and clear out files that no longer referenced by any
  * snapshots.
+ *
+ * @opensearch.internal
  */
 public class BlobStoreIndexShardSnapshots implements Iterable<SnapshotFiles>, ToXContentFragment {
 
@@ -176,11 +178,21 @@ public Iterator<SnapshotFiles> iterator() {
         return shardSnapshots.iterator();
     }
 
+    /**
+     * Fields for blob store index shard snapshot
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String FILES = "files";
         static final String SNAPSHOTS = "snapshots";
     }
 
+    /**
+     * Parse fields for blob store index shard snapshots
+     *
+     * @opensearch.internal
+     */
     static final class ParseFields {
         static final ParseField FILES = new ParseField("files");
         static final ParseField SHARD_STATE_ID = new ParseField("shard_state_id");
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/IndexShardSnapshot.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/IndexShardSnapshot.java
new file mode 100644
index 0000000000000..e79b9069ef16a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/IndexShardSnapshot.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.snapshots.blobstore;
+
+import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+
+/**
+ * Base interface for shard snapshot status
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface IndexShardSnapshot {
+    IndexShardSnapshotStatus getIndexShardSnapshotStatus();
+}
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/RateLimitingInputStream.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/RateLimitingInputStream.java
index 6b5ce49289ac7..ee601f96ecee1 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/blobstore/RateLimitingInputStream.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/RateLimitingInputStream.java
@@ -33,6 +33,7 @@
 package org.opensearch.index.snapshots.blobstore;
 
 import org.apache.lucene.store.RateLimiter;
+import org.opensearch.common.StreamLimiter;
 
 import java.io.FilterInputStream;
 import java.io.IOException;
@@ -41,43 +42,22 @@
 
 /**
  * Rate limiting wrapper for InputStream
+ *
+ * @opensearch.internal
  */
 public class RateLimitingInputStream extends FilterInputStream {
 
-    private final Supplier<RateLimiter> rateLimiterSupplier;
-
-    private final Listener listener;
-
-    private long bytesSinceLastRateLimit;
-
-    public interface Listener {
-        void onPause(long nanos);
-    }
+    private final StreamLimiter streamLimiter;
 
-    public RateLimitingInputStream(InputStream delegate, Supplier<RateLimiter> rateLimiterSupplier, Listener listener) {
+    public RateLimitingInputStream(InputStream delegate, Supplier<RateLimiter> rateLimiterSupplier, StreamLimiter.Listener listener) {
         super(delegate);
-        this.rateLimiterSupplier = rateLimiterSupplier;
-        this.listener = listener;
-    }
-
-    private void maybePause(int bytes) throws IOException {
-        bytesSinceLastRateLimit += bytes;
-        final RateLimiter rateLimiter = rateLimiterSupplier.get();
-        if (rateLimiter != null) {
-            if (bytesSinceLastRateLimit >= rateLimiter.getMinPauseCheckBytes()) {
-                long pause = rateLimiter.pause(bytesSinceLastRateLimit);
-                bytesSinceLastRateLimit = 0;
-                if (pause > 0) {
-                    listener.onPause(pause);
-                }
-            }
-        }
+        this.streamLimiter = new StreamLimiter(rateLimiterSupplier, listener);
     }
 
     @Override
     public int read() throws IOException {
         int b = super.read();
-        maybePause(1);
+        streamLimiter.maybePause(1);
         return b;
     }
 
@@ -85,7 +65,7 @@ public int read() throws IOException {
     public int read(byte[] b, int off, int len) throws IOException {
         int n = super.read(b, off, len);
         if (n > 0) {
-            maybePause(n);
+            streamLimiter.maybePause(n);
         }
         return n;
     }
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshot.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshot.java
new file mode 100644
index 0000000000000..eefc1469a06a0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshot.java
@@ -0,0 +1,450 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.snapshots.blobstore;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Remote Store based Shard snapshot metadata
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreShardShallowCopySnapshot implements ToXContentFragment, IndexShardSnapshot {
+
+    private final String snapshot;
+    private final String version;
+    private final long indexVersion;
+    private final long startTime;
+    private final long time;
+    private final int totalFileCount;
+    private final long totalSize;
+    private final long primaryTerm;
+    private final long commitGeneration;
+    private final String remoteStoreRepository;
+    private final String repositoryBasePath;
+    private final String indexUUID;
+    private final List<String> fileNames;
+
+    static final String DEFAULT_VERSION = "1";
+    static final String NAME = "name";
+    static final String VERSION = "version";
+    static final String INDEX_VERSION = "index_version";
+    static final String START_TIME = "start_time";
+    static final String TIME = "time";
+
+    static final String INDEX_UUID = "index_uuid";
+
+    static final String REMOTE_STORE_REPOSITORY = "remote_store_repository";
+    static final String REPOSITORY_BASE_PATH = "remote_store_repository_base_path";
+    static final String FILE_NAMES = "file_names";
+
+    static final String PRIMARY_TERM = "primary_term";
+
+    static final String COMMIT_GENERATION = "commit_generation";
+
+    static final String TOTAL_FILE_COUNT = "number_of_files";
+    static final String TOTAL_SIZE = "total_size";
+
+    private static final ParseField PARSE_NAME = new ParseField(NAME);
+    private static final ParseField PARSE_VERSION = new ParseField(VERSION);
+    private static final ParseField PARSE_PRIMARY_TERM = new ParseField(PRIMARY_TERM);
+    private static final ParseField PARSE_COMMIT_GENERATION = new ParseField(COMMIT_GENERATION);
+    private static final ParseField PARSE_INDEX_VERSION = new ParseField(INDEX_VERSION, "index-version");
+    private static final ParseField PARSE_START_TIME = new ParseField(START_TIME);
+    private static final ParseField PARSE_TIME = new ParseField(TIME);
+    private static final ParseField PARSE_TOTAL_FILE_COUNT = new ParseField(TOTAL_FILE_COUNT);
+    private static final ParseField PARSE_TOTAL_SIZE = new ParseField(TOTAL_SIZE);
+    private static final ParseField PARSE_INDEX_UUID = new ParseField(INDEX_UUID);
+    private static final ParseField PARSE_REMOTE_STORE_REPOSITORY = new ParseField(REMOTE_STORE_REPOSITORY);
+    private static final ParseField PARSE_REPOSITORY_BASE_PATH = new ParseField(REPOSITORY_BASE_PATH);
+    private static final ParseField PARSE_FILE_NAMES = new ParseField(FILE_NAMES);
+
+    /**
+     * Serializes shard snapshot metadata info into JSON
+     *
+     * @param builder  XContent builder
+     * @param params   parameters
+     */
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field(VERSION, version);
+        builder.field(NAME, snapshot);
+        builder.field(INDEX_VERSION, indexVersion);
+        builder.field(START_TIME, startTime);
+        builder.field(TIME, time);
+        builder.field(TOTAL_FILE_COUNT, totalFileCount);
+        builder.field(TOTAL_SIZE, totalSize);
+        builder.field(INDEX_UUID, indexUUID);
+        builder.field(REMOTE_STORE_REPOSITORY, remoteStoreRepository);
+        builder.field(COMMIT_GENERATION, commitGeneration);
+        builder.field(PRIMARY_TERM, primaryTerm);
+        builder.field(REPOSITORY_BASE_PATH, repositoryBasePath);
+        builder.startArray(FILE_NAMES);
+        for (String fileName : fileNames) {
+            builder.value(fileName);
+        }
+        builder.endArray();
+        return builder;
+    }
+
+    public RemoteStoreShardShallowCopySnapshot(
+        String snapshot,
+        long indexVersion,
+        long primaryTerm,
+        long commitGeneration,
+        long startTime,
+        long time,
+        int totalFileCount,
+        long totalSize,
+        String indexUUID,
+        String remoteStoreRepository,
+        String repositoryBasePath,
+        List<String> fileNames
+    ) {
+        this.version = DEFAULT_VERSION;
+        verifyParameters(
+            version,
+            snapshot,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath
+        );
+        this.snapshot = snapshot;
+        this.indexVersion = indexVersion;
+        this.primaryTerm = primaryTerm;
+        this.commitGeneration = commitGeneration;
+        this.startTime = startTime;
+        this.time = time;
+        this.totalFileCount = totalFileCount;
+        this.totalSize = totalSize;
+        this.indexUUID = indexUUID;
+        this.remoteStoreRepository = remoteStoreRepository;
+        this.repositoryBasePath = repositoryBasePath;
+        this.fileNames = fileNames;
+    }
+
+    private RemoteStoreShardShallowCopySnapshot(
+        String version,
+        String snapshot,
+        long indexVersion,
+        long primaryTerm,
+        long commitGeneration,
+        long startTime,
+        long time,
+        int totalFileCount,
+        long totalSize,
+        String indexUUID,
+        String remoteStoreRepository,
+        String repositoryBasePath,
+        List<String> fileNames
+    ) {
+        verifyParameters(
+            version,
+            snapshot,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath
+        );
+        this.version = version;
+        this.snapshot = snapshot;
+        this.indexVersion = indexVersion;
+        this.primaryTerm = primaryTerm;
+        this.commitGeneration = commitGeneration;
+        this.startTime = startTime;
+        this.time = time;
+        this.totalFileCount = totalFileCount;
+        this.totalSize = totalSize;
+        this.indexUUID = indexUUID;
+        this.remoteStoreRepository = remoteStoreRepository;
+        this.repositoryBasePath = repositoryBasePath;
+        this.fileNames = fileNames;
+    }
+
+    /**
+     * Parses shard snapshot metadata
+     *
+     * @param parser parser
+     * @return shard snapshot metadata
+     */
+    public static RemoteStoreShardShallowCopySnapshot fromXContent(XContentParser parser) throws IOException {
+        String snapshot = null;
+        String version = null;
+        long indexVersion = -1;
+        long startTime = 0;
+        long time = 0;
+        int totalFileCount = 0;
+        long totalSize = 0;
+        String indexUUID = null;
+        String remoteStoreRepository = null;
+        String repositoryBasePath = null;
+        long primaryTerm = -1;
+        long commitGeneration = -1;
+        List<String> fileNames = new ArrayList<>();
+
+        if (parser.currentToken() == null) { // fresh parser? move to the first token
+            parser.nextToken();
+        }
+        XContentParser.Token token;
+        String currentFieldName = parser.currentName();
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                currentFieldName = parser.currentName();
+            } else if (token.isValue()) {
+                if (PARSE_NAME.match(currentFieldName, parser.getDeprecationHandler())) {
+                    snapshot = parser.text();
+                } else if (PARSE_VERSION.match(currentFieldName, parser.getDeprecationHandler())) {
+                    version = parser.text();
+                } else if (PARSE_INDEX_VERSION.match(currentFieldName, parser.getDeprecationHandler())) {
+                    indexVersion = parser.longValue();
+                } else if (PARSE_PRIMARY_TERM.match(currentFieldName, parser.getDeprecationHandler())) {
+                    primaryTerm = parser.longValue();
+                } else if (PARSE_COMMIT_GENERATION.match(currentFieldName, parser.getDeprecationHandler())) {
+                    commitGeneration = parser.longValue();
+                } else if (PARSE_START_TIME.match(currentFieldName, parser.getDeprecationHandler())) {
+                    startTime = parser.longValue();
+                } else if (PARSE_TIME.match(currentFieldName, parser.getDeprecationHandler())) {
+                    time = parser.longValue();
+                } else if (PARSE_TOTAL_FILE_COUNT.match(currentFieldName, parser.getDeprecationHandler())) {
+                    totalFileCount = parser.intValue();
+                } else if (PARSE_TOTAL_SIZE.match(currentFieldName, parser.getDeprecationHandler())) {
+                    totalSize = parser.longValue();
+                } else if (PARSE_INDEX_UUID.match(currentFieldName, parser.getDeprecationHandler())) {
+                    indexUUID = parser.text();
+                } else if (PARSE_REMOTE_STORE_REPOSITORY.match(currentFieldName, parser.getDeprecationHandler())) {
+                    remoteStoreRepository = parser.text();
+                } else if (PARSE_REPOSITORY_BASE_PATH.match(currentFieldName, parser.getDeprecationHandler())) {
+                    repositoryBasePath = parser.text();
+                } else {
+                    throw new OpenSearchParseException("unknown parameter [{}]", currentFieldName);
+                }
+            } else if (token == XContentParser.Token.START_ARRAY) {
+                if (PARSE_FILE_NAMES.match(currentFieldName, parser.getDeprecationHandler())) {
+                    while ((parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        fileNames.add(parser.text());
+                    }
+                } else {
+                    parser.skipChildren();
+                }
+            } else {
+                parser.skipChildren();
+            }
+        }
+
+        return new RemoteStoreShardShallowCopySnapshot(
+            version,
+            snapshot,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            startTime,
+            time,
+            totalFileCount,
+            totalSize,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath,
+            fileNames
+        );
+    }
+
+    /**
+     * Returns shard primary Term during snapshot creation
+     *
+     * @return primary Term
+     */
+    public long getPrimaryTerm() {
+        return primaryTerm;
+    }
+
+    /**
+     * Returns snapshot commit generation
+     *
+     * @return commit Generation
+     */
+    public long getCommitGeneration() {
+        return commitGeneration;
+    }
+
+    /**
+     * Returns Index UUID
+     *
+     * @return index UUID
+     */
+    public String getIndexUUID() {
+        return indexUUID;
+    }
+
+    /**
+     * Returns Remote Store Repository Name
+     *
+     * @return remote store Repository Name
+     */
+    public String getRemoteStoreRepository() {
+        return remoteStoreRepository;
+    }
+
+    /**
+     * Returns Remote Store Repository Base Path
+     *
+     * @return repository base path
+     */
+    public String getRepositoryBasePath() {
+        return repositoryBasePath;
+    }
+
+    /**
+     * Returns snapshot name
+     *
+     * @return snapshot name
+     */
+    public String snapshot() {
+        return snapshot;
+    }
+
+    /**
+     * Returns list of files in the shard
+     *
+     * @return list of files
+     */
+
+    /**
+     * Returns snapshot start time
+     */
+    public long startTime() {
+        return startTime;
+    }
+
+    /**
+     * Returns snapshot running time
+     */
+    public long time() {
+        return time;
+    }
+
+    /**
+     * Returns incremental of files that were snapshotted
+     */
+    public int incrementalFileCount() {
+        return 0;
+    }
+
+    /**
+     * Returns total number of files that are referenced by this snapshot
+     */
+    public int totalFileCount() {
+        return totalFileCount;
+    }
+
+    /**
+     * Returns incremental of files size that were snapshotted
+     */
+    public long incrementalSize() {
+        return 0;
+    }
+
+    /**
+     * Returns total size of all files that where snapshotted
+     */
+    public long totalSize() {
+        return totalSize;
+    }
+
+    private void verifyParameters(
+        String version,
+        String snapshot,
+        long indexVersion,
+        long primaryTerm,
+        long commitGeneration,
+        String indexUUID,
+        String remoteStoreRepository,
+        String repositoryBasePath
+    ) {
+        String exceptionStr = null;
+        if (version == null) {
+            exceptionStr = "Invalid Version Provided";
+        }
+        if (snapshot == null) {
+            exceptionStr = "Invalid/Missing Snapshot Name";
+        }
+        if (indexVersion < 0) {
+            exceptionStr = "Invalid Index Version";
+        }
+        if (primaryTerm < 0) {
+            exceptionStr = "Invalid Primary Term";
+        }
+        if (commitGeneration < 0) {
+            exceptionStr = "Invalid Commit Generation";
+        }
+        if (indexUUID == null) {
+            exceptionStr = "Invalid/Missing Index UUID";
+        }
+        if (remoteStoreRepository == null) {
+            exceptionStr = "Invalid/Missing Remote Store Repository";
+        }
+        if (repositoryBasePath == null) {
+            exceptionStr = "Invalid/Missing Repository Base Path";
+        }
+        if (exceptionStr != null) {
+            throw new IllegalArgumentException(exceptionStr);
+        }
+    }
+
+    /**
+     * Creates a new instance which has a different name and zero incremental file counts but is identical to this instance in terms of the files
+     * it references.
+     *
+     * @param targetSnapshotName target snapshot name
+     * @param startTime          time the clone operation on the repository was started
+     * @param time               time it took to create the clone
+     */
+    public RemoteStoreShardShallowCopySnapshot asClone(String targetSnapshotName, long startTime, long time) {
+        return new RemoteStoreShardShallowCopySnapshot(
+            targetSnapshotName,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            startTime,
+            time,
+            totalFileCount,
+            totalSize,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath,
+            fileNames
+        );
+    }
+
+    @Override
+    public IndexShardSnapshotStatus getIndexShardSnapshotStatus() {
+        return IndexShardSnapshotStatus.newDone(
+            startTime,
+            time,
+            incrementalFileCount(),
+            totalFileCount,
+            incrementalSize(),
+            totalSize,
+            null
+        ); // Not adding a real generation here as it doesn't matter to callers
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/SlicedInputStream.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/SlicedInputStream.java
index c5b227341fbe5..298b101a86299 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/blobstore/SlicedInputStream.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/SlicedInputStream.java
@@ -31,10 +31,11 @@
 
 package org.opensearch.index.snapshots.blobstore;
 
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Objects;
 
 /**
  *  A {@link SlicedInputStream} is a logical
@@ -43,6 +44,8 @@
  * of all logical sub-streams ahead of time. Instead, {@link #openSlice(int)} is called
  * if a new slice is required. Each slice is closed once it's been fully consumed or if
  * close is called before.
+ *
+ * @opensearch.internal
  */
 public abstract class SlicedInputStream extends InputStream {
     private int slice = 0;
@@ -98,6 +101,11 @@ public final int read() throws IOException {
 
     @Override
     public final int read(byte[] buffer, int offset, int length) throws IOException {
+        Objects.checkFromIndexSize(offset, length, buffer.length);
+        if (length == 0) {
+            return 0;
+        }
+
         final InputStream stream = currentStream();
         if (stream == null) {
             return -1;
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/SnapshotFiles.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/SnapshotFiles.java
index 81075472c00da..9ac002f2bc60c 100644
--- a/server/src/main/java/org/opensearch/index/snapshots/blobstore/SnapshotFiles.java
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/SnapshotFiles.java
@@ -41,6 +41,8 @@
 
 /**
  * Contains a list of files participating in a snapshot
+ *
+ * @opensearch.internal
  */
 public class SnapshotFiles {
 
diff --git a/server/src/main/java/org/opensearch/index/snapshots/blobstore/package-info.java b/server/src/main/java/org/opensearch/index/snapshots/blobstore/package-info.java
new file mode 100644
index 0000000000000..0d1eb6f5942ea
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/snapshots/blobstore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes implementing blob store for snapshot / restore */
+package org.opensearch.index.snapshots.blobstore;
diff --git a/server/src/main/java/org/opensearch/index/snapshots/package-info.java b/server/src/main/java/org/opensearch/index/snapshots/package-info.java
new file mode 100644
index 0000000000000..7cebfe5152d48
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/snapshots/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Foundation classes for snapshot / restore */
+package org.opensearch.index.snapshots;
diff --git a/server/src/main/java/org/opensearch/index/stats/IndexingPressurePerShardStats.java b/server/src/main/java/org/opensearch/index/stats/IndexingPressurePerShardStats.java
index 1786b02c38643..d69ae02fa8e34 100644
--- a/server/src/main/java/org/opensearch/index/stats/IndexingPressurePerShardStats.java
+++ b/server/src/main/java/org/opensearch/index/stats/IndexingPressurePerShardStats.java
@@ -8,17 +8,22 @@
 
 package org.opensearch.index.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.ShardIndexingPressureTracker;
 
 import java.io.IOException;
 
+/**
+ * Per shard indexing pressure statistics
+ *
+ * @opensearch.internal
+ */
 public class IndexingPressurePerShardStats implements Writeable, ToXContentFragment {
 
     private final String shardId;
diff --git a/server/src/main/java/org/opensearch/index/stats/IndexingPressureStats.java b/server/src/main/java/org/opensearch/index/stats/IndexingPressureStats.java
index fd13b170e3fc2..03fade6ded668 100644
--- a/server/src/main/java/org/opensearch/index/stats/IndexingPressureStats.java
+++ b/server/src/main/java/org/opensearch/index/stats/IndexingPressureStats.java
@@ -33,15 +33,20 @@
 package org.opensearch.index.stats;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Base indexing pressure statistics
+ *
+ * @opensearch.internal
+ */
 public class IndexingPressureStats implements Writeable, ToXContentFragment {
 
     private final long totalCombinedCoordinatingAndPrimaryBytes;
diff --git a/server/src/main/java/org/opensearch/index/stats/ShardIndexingPressureStats.java b/server/src/main/java/org/opensearch/index/stats/ShardIndexingPressureStats.java
index 7e928e0e4c094..b7071d883bb4c 100644
--- a/server/src/main/java/org/opensearch/index/stats/ShardIndexingPressureStats.java
+++ b/server/src/main/java/org/opensearch/index/stats/ShardIndexingPressureStats.java
@@ -8,18 +8,23 @@
 
 package org.opensearch.index.stats;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Cumulative shard indexing pressure stats
+ *
+ * @opensearch.internal
+ */
 public class ShardIndexingPressureStats implements Writeable, ToXContentFragment {
 
     private final Map<ShardId, IndexingPressurePerShardStats> shardIndexingPressureStore;
diff --git a/server/src/main/java/org/opensearch/index/stats/package-info.java b/server/src/main/java/org/opensearch/index/stats/package-info.java
new file mode 100644
index 0000000000000..f431a013b82b1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/stats/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Classes responsible for handing ShardIndexingPressure statistics */
+package org.opensearch.index.stats;
diff --git a/server/src/main/java/org/opensearch/index/store/ByteSizeCachingDirectory.java b/server/src/main/java/org/opensearch/index/store/ByteSizeCachingDirectory.java
index f9af1847dfff6..9fe72c0da1062 100644
--- a/server/src/main/java/org/opensearch/index/store/ByteSizeCachingDirectory.java
+++ b/server/src/main/java/org/opensearch/index/store/ByteSizeCachingDirectory.java
@@ -47,8 +47,18 @@
 import java.nio.file.NoSuchFileException;
 import java.util.Set;
 
+/**
+ * Caching directory sized in bytes
+ *
+ * @opensearch.internal
+ */
 final class ByteSizeCachingDirectory extends FilterDirectory {
 
+    /**
+     * Internal caching size and modulo count
+     *
+     * @opensearch.internal
+     */
     private static class SizeAndModCount {
         final long size;
         final long modCount;
diff --git a/server/src/main/java/org/opensearch/index/store/DirectoryFileTransferTracker.java b/server/src/main/java/org/opensearch/index/store/DirectoryFileTransferTracker.java
new file mode 100644
index 0000000000000..7ad48cb56a33b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/DirectoryFileTransferTracker.java
@@ -0,0 +1,254 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.Directory;
+import org.opensearch.common.util.MovingAverage;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Tracks the amount of bytes transferred between two {@link Directory} instances
+ *
+ * @opensearch.internal
+ */
+public class DirectoryFileTransferTracker {
+    /**
+     * Cumulative size of files (in bytes) attempted to be transferred over from the source {@link Directory}
+     */
+    private final AtomicLong transferredBytesStarted = new AtomicLong();
+
+    /**
+     * Cumulative size of files (in bytes) successfully transferred over from the source {@link Directory}
+     */
+    private final AtomicLong transferredBytesFailed = new AtomicLong();
+
+    /**
+     * Cumulative size of files (in bytes) failed in transfer over from the source {@link Directory}
+     */
+    private final AtomicLong transferredBytesSucceeded = new AtomicLong();
+
+    /**
+     * Time in milliseconds for the last successful transfer from the source {@link Directory}
+     */
+    private final AtomicLong lastTransferTimestampMs = new AtomicLong();
+
+    /**
+     * Cumulative time in milliseconds spent in successful transfers from the source {@link Directory}
+     */
+    private final AtomicLong totalTransferTimeInMs = new AtomicLong();
+
+    /**
+     * Provides moving average over the last N total size in bytes of files transferred from the source {@link Directory}.
+     * N is window size
+     */
+    private final AtomicReference<MovingAverage> transferredBytesMovingAverageReference;
+
+    private final AtomicLong lastSuccessfulTransferInBytes = new AtomicLong();
+
+    /**
+     * Provides moving average over the last N transfer speed (in bytes/s) of segment files transferred from the source {@link Directory}.
+     * N is window size
+     */
+    private final AtomicReference<MovingAverage> transferredBytesPerSecMovingAverageReference;
+
+    private final int DIRECTORY_FILES_TRANSFER_DEFAULT_WINDOW_SIZE = 20;
+
+    // Getters and Setters, all are visible for testing
+    public long getTransferredBytesStarted() {
+        return transferredBytesStarted.get();
+    }
+
+    public void addTransferredBytesStarted(long size) {
+        transferredBytesStarted.getAndAdd(size);
+    }
+
+    public long getTransferredBytesFailed() {
+        return transferredBytesFailed.get();
+    }
+
+    public void addTransferredBytesFailed(long size, long startTimeInMs) {
+        transferredBytesFailed.getAndAdd(size);
+        addTotalTransferTimeInMs(Math.max(1, System.currentTimeMillis() - startTimeInMs));
+    }
+
+    public long getTransferredBytesSucceeded() {
+        return transferredBytesSucceeded.get();
+    }
+
+    public void addTransferredBytesSucceeded(long size, long startTimeInMs) {
+        transferredBytesSucceeded.getAndAdd(size);
+        updateSuccessfulTransferSize(size);
+        long currentTimeInMs = System.currentTimeMillis();
+        updateLastTransferTimestampMs(currentTimeInMs);
+        long timeTakenInMS = Math.max(1, currentTimeInMs - startTimeInMs);
+        addTotalTransferTimeInMs(timeTakenInMS);
+        addTransferredBytesPerSec((size * 1_000L) / timeTakenInMS);
+    }
+
+    public boolean isTransferredBytesPerSecAverageReady() {
+        return transferredBytesPerSecMovingAverageReference.get().isReady();
+    }
+
+    public double getTransferredBytesPerSecAverage() {
+        return transferredBytesPerSecMovingAverageReference.get().getAverage();
+    }
+
+    public void addTransferredBytesPerSec(long bytesPerSec) {
+        this.transferredBytesPerSecMovingAverageReference.get().record(bytesPerSec);
+    }
+
+    public boolean isTransferredBytesAverageReady() {
+        return transferredBytesMovingAverageReference.get().isReady();
+    }
+
+    public double getTransferredBytesAverage() {
+        return transferredBytesMovingAverageReference.get().getAverage();
+    }
+
+    public void updateLastSuccessfulTransferInBytes(long size) {
+        lastSuccessfulTransferInBytes.set(size);
+    }
+
+    public void updateSuccessfulTransferSize(long size) {
+        updateLastSuccessfulTransferInBytes(size);
+        this.transferredBytesMovingAverageReference.get().record(size);
+    }
+
+    public long getLastTransferTimestampMs() {
+        return lastTransferTimestampMs.get();
+    }
+
+    public void updateLastTransferTimestampMs(long downloadTimestampInMs) {
+        this.lastTransferTimestampMs.set(downloadTimestampInMs);
+    }
+
+    public void addTotalTransferTimeInMs(long totalTransferTimeInMs) {
+        this.totalTransferTimeInMs.addAndGet(totalTransferTimeInMs);
+    }
+
+    public long getTotalTransferTimeInMs() {
+        return totalTransferTimeInMs.get();
+    }
+
+    public DirectoryFileTransferTracker() {
+        transferredBytesMovingAverageReference = new AtomicReference<>(new MovingAverage(DIRECTORY_FILES_TRANSFER_DEFAULT_WINDOW_SIZE));
+        transferredBytesPerSecMovingAverageReference = new AtomicReference<>(
+            new MovingAverage(DIRECTORY_FILES_TRANSFER_DEFAULT_WINDOW_SIZE)
+        );
+    }
+
+    public DirectoryFileTransferTracker.Stats stats() {
+        return new Stats(
+            transferredBytesStarted.get(),
+            transferredBytesFailed.get(),
+            transferredBytesSucceeded.get(),
+            lastTransferTimestampMs.get(),
+            totalTransferTimeInMs.get(),
+            transferredBytesMovingAverageReference.get().getAverage(),
+            lastSuccessfulTransferInBytes.get(),
+            transferredBytesPerSecMovingAverageReference.get().getAverage()
+        );
+    }
+
+    /**
+     * Represents the tracker's stats presentable to an API.
+     *
+     * @opensearch.internal
+     */
+    public static class Stats implements Writeable {
+        public final long transferredBytesStarted;
+        public final long transferredBytesFailed;
+        public final long transferredBytesSucceeded;
+        public final long lastTransferTimestampMs;
+        public final long totalTransferTimeInMs;
+        public final double transferredBytesMovingAverage;
+        public final long lastSuccessfulTransferInBytes;
+        public final double transferredBytesPerSecMovingAverage;
+
+        public Stats(
+            long transferredBytesStarted,
+            long transferredBytesFailed,
+            long downloadBytesSucceeded,
+            long lastTransferTimestampMs,
+            long totalTransferTimeInMs,
+            double transferredBytesMovingAverage,
+            long lastSuccessfulTransferInBytes,
+            double transferredBytesPerSecMovingAverage
+        ) {
+            this.transferredBytesStarted = transferredBytesStarted;
+            this.transferredBytesFailed = transferredBytesFailed;
+            this.transferredBytesSucceeded = downloadBytesSucceeded;
+            this.lastTransferTimestampMs = lastTransferTimestampMs;
+            this.totalTransferTimeInMs = totalTransferTimeInMs;
+            this.transferredBytesMovingAverage = transferredBytesMovingAverage;
+            this.lastSuccessfulTransferInBytes = lastSuccessfulTransferInBytes;
+            this.transferredBytesPerSecMovingAverage = transferredBytesPerSecMovingAverage;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            this.transferredBytesStarted = in.readLong();
+            this.transferredBytesFailed = in.readLong();
+            this.transferredBytesSucceeded = in.readLong();
+            this.lastTransferTimestampMs = in.readLong();
+            this.totalTransferTimeInMs = in.readLong();
+            this.transferredBytesMovingAverage = in.readDouble();
+            this.lastSuccessfulTransferInBytes = in.readLong();
+            this.transferredBytesPerSecMovingAverage = in.readDouble();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeLong(transferredBytesStarted);
+            out.writeLong(transferredBytesFailed);
+            out.writeLong(transferredBytesSucceeded);
+            out.writeLong(lastTransferTimestampMs);
+            out.writeLong(totalTransferTimeInMs);
+            out.writeDouble(transferredBytesMovingAverage);
+            out.writeLong(lastSuccessfulTransferInBytes);
+            out.writeDouble(transferredBytesPerSecMovingAverage);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (obj == null || getClass() != obj.getClass()) return false;
+            Stats stats = (Stats) obj;
+
+            return transferredBytesStarted == stats.transferredBytesStarted
+                && transferredBytesFailed == stats.transferredBytesFailed
+                && transferredBytesSucceeded == stats.transferredBytesSucceeded
+                && lastTransferTimestampMs == stats.lastTransferTimestampMs
+                && totalTransferTimeInMs == stats.totalTransferTimeInMs
+                && Double.compare(stats.transferredBytesMovingAverage, transferredBytesMovingAverage) == 0
+                && lastSuccessfulTransferInBytes == stats.lastSuccessfulTransferInBytes
+                && Double.compare(stats.transferredBytesPerSecMovingAverage, transferredBytesPerSecMovingAverage) == 0;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(
+                transferredBytesStarted,
+                transferredBytesFailed,
+                transferredBytesSucceeded,
+                lastTransferTimestampMs,
+                totalTransferTimeInMs,
+                transferredBytesMovingAverage,
+                lastSuccessfulTransferInBytes,
+                transferredBytesPerSecMovingAverage
+            );
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/FsDirectoryFactory.java b/server/src/main/java/org/opensearch/index/store/FsDirectoryFactory.java
index 2539968b20b0e..a46b641d1423f 100644
--- a/server/src/main/java/org/opensearch/index/store/FsDirectoryFactory.java
+++ b/server/src/main/java/org/opensearch/index/store/FsDirectoryFactory.java
@@ -45,7 +45,8 @@
 import org.apache.lucene.store.SimpleFSLockFactory;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.ShardPath;
@@ -56,7 +57,14 @@
 import java.nio.file.Path;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+/**
+ * Factory for a filesystem directory
+ *
+ * @opensearch.internal
+ */
 public class FsDirectoryFactory implements IndexStorePlugin.DirectoryFactory {
 
     public static final Setting<LockFactory> INDEX_LOCK_FACTOR_SETTING = new Setting<>("index.store.fs.fs_lock", "native", (s) -> {
@@ -92,9 +100,24 @@ protected Directory newFSDirectory(Path location, LockFactory lockFactory, Index
             case HYBRIDFS:
                 // Use Lucene defaults
                 final FSDirectory primaryDirectory = FSDirectory.open(location, lockFactory);
+                final Set<String> nioExtensions;
+                final Set<String> mmapExtensions = Set.copyOf(indexSettings.getValue(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS));
+                if (mmapExtensions.equals(
+                    new HashSet(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getDefault(Settings.EMPTY))
+                ) == false) {
+                    // If the mmap extension setting was defined, then compute nio extensions by subtracting out the
+                    // mmap extensions from the set of all extensions.
+                    nioExtensions = Stream.concat(
+                        IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS.getDefault(Settings.EMPTY).stream(),
+                        IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getDefault(Settings.EMPTY).stream()
+                    ).filter(e -> mmapExtensions.contains(e) == false).collect(Collectors.toUnmodifiableSet());
+                } else {
+                    // Otherwise, get the list of nio extensions from the nio setting
+                    nioExtensions = Set.copyOf(indexSettings.getValue(IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS));
+                }
                 if (primaryDirectory instanceof MMapDirectory) {
                     MMapDirectory mMapDirectory = (MMapDirectory) primaryDirectory;
-                    return new HybridDirectory(lockFactory, setPreload(mMapDirectory, lockFactory, preLoadExtensions));
+                    return new HybridDirectory(lockFactory, setPreload(mMapDirectory, lockFactory, preLoadExtensions), nioExtensions);
                 } else {
                     return primaryDirectory;
                 }
@@ -130,12 +153,19 @@ public static boolean isHybridFs(Directory directory) {
         return unwrap instanceof HybridDirectory;
     }
 
+    /**
+     * A hybrid directory implementation
+     *
+     * @opensearch.internal
+     */
     static final class HybridDirectory extends NIOFSDirectory {
         private final MMapDirectory delegate;
+        private final Set<String> nioExtensions;
 
-        HybridDirectory(LockFactory lockFactory, MMapDirectory delegate) throws IOException {
+        HybridDirectory(LockFactory lockFactory, MMapDirectory delegate, Set<String> nioExtensions) throws IOException {
             super(delegate.getDirectory(), lockFactory);
             this.delegate = delegate;
+            this.nioExtensions = nioExtensions;
         }
 
         @Override
@@ -154,48 +184,26 @@ public IndexInput openInput(String name, IOContext context) throws IOException {
             }
         }
 
+        boolean useDelegate(String name) {
+            final String extension = FileSwitchDirectory.getExtension(name);
+            return nioExtensions.contains(extension) == false;
+        }
+
         @Override
         public void close() throws IOException {
             IOUtils.close(super::close, delegate);
         }
 
-        boolean useDelegate(String name) {
-            String extension = FileSwitchDirectory.getExtension(name);
-            switch (extension) {
-                // Norms, doc values and term dictionaries are typically performance-sensitive and hot in the page
-                // cache, so we use mmap, which provides better performance.
-                case "nvd":
-                case "dvd":
-                case "tim":
-                    // We want to open the terms index and KD-tree index off-heap to save memory, but this only performs
-                    // well if using mmap.
-                case "tip":
-                    // dim files only apply up to lucene 8.x indices. It can be removed once we are in lucene 10
-                case "dim":
-                case "kdd":
-                case "kdi":
-                    // Compound files are tricky because they store all the information for the segment. Benchmarks
-                    // suggested that not mapping them hurts performance.
-                case "cfs":
-                    // MMapDirectory has special logic to read long[] arrays in little-endian order that helps speed
-                    // up the decoding of postings. The same logic applies to positions (.pos) of offsets (.pay) but we
-                    // are not mmaping them as queries that leverage positions are more costly and the decoding of postings
-                    // tends to be less a bottleneck.
-                case "doc":
-                    return true;
-                // Other files are either less performance-sensitive (e.g. stored field index, norms metadata)
-                // or are large and have a random access pattern and mmap leads to page cache trashing
-                // (e.g. stored fields and term vectors).
-                default:
-                    return false;
-            }
-        }
-
         MMapDirectory getDelegate() {
             return delegate;
         }
     }
 
+    /**
+     * Pre loaded mmap directory
+     *
+     * @opensearch.internal
+     */
     // TODO it would be nice to share code between PreLoadMMapDirectory and HybridDirectory but due to the nesting aspect of
     // directories here makes it tricky. It would be nice to allow MMAPDirectory to pre-load on a per IndexInput basis.
     static final class PreLoadMMapDirectory extends MMapDirectory {
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteBufferedIndexOutput.java b/server/src/main/java/org/opensearch/index/store/RemoteBufferedIndexOutput.java
new file mode 100644
index 0000000000000..ad44a3bf75678
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteBufferedIndexOutput.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.DataInput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Class for output to a file in a {@link RemoteBufferedOutputDirectory}. This is right now used only for writing locks
+ * in remote store. in the future, we can use it for other operations as well.
+ * The current limitation of this is we keep all the file content in memory till we call close(),
+ * So this class should be used to write small files (in MBs).
+ * TODO: extend the class to continously write to the store if content size in buffer gets higher than a specific size.
+ * @see RemoteBufferedOutputDirectory
+ *
+ * @opensearch.internal
+ */
+public class RemoteBufferedIndexOutput extends RemoteIndexOutput {
+    private final BytesStreamOutput out;
+    private final OutputStreamIndexOutput indexOutputBuffer;
+    // visible for testing
+    static final int BUFFER_SIZE = 4096;
+
+    public RemoteBufferedIndexOutput(String name, BlobContainer blobContainer, int bufferSize) {
+        super(name, blobContainer);
+        out = new BytesStreamOutput();
+        indexOutputBuffer = new OutputStreamIndexOutput(name, name, out, bufferSize);
+    }
+
+    public RemoteBufferedIndexOutput(String name, BlobContainer blobContainer) {
+        this(name, blobContainer, BUFFER_SIZE);
+    }
+
+    // Visible for testing
+    RemoteBufferedIndexOutput(String name, BlobContainer blobContainer, BytesStreamOutput out, OutputStreamIndexOutput indexOutputBuffer) {
+        super(name, blobContainer);
+        this.out = out;
+        this.indexOutputBuffer = indexOutputBuffer;
+    }
+
+    @Override
+    public void copyBytes(DataInput input, long numBytes) throws IOException {
+        indexOutputBuffer.copyBytes(input, numBytes);
+    }
+
+    /**
+     * when we trigger close() to close the stream, we will first flush the buffer to output stream and then write all
+     * data to blob container and close the output stream.
+     *
+     */
+    @Override
+    public void close() throws IOException {
+
+        try (final BytesStreamOutput outStream = out; InputStream stream = out.bytes().streamInput()) {
+            indexOutputBuffer.close();
+            blobContainer.writeBlob(getName(), stream, out.bytes().length(), false);
+        }
+
+    }
+
+    /**
+     * This method will write Bytes to the stream we are maintaining.
+     *
+     */
+    @Override
+    public void writeByte(byte b) throws IOException {
+        indexOutputBuffer.writeByte(b);
+    }
+
+    /**
+     * This method will write a byte array to the stream we are maintaining.
+     *
+     */
+    @Override
+    public void writeBytes(byte[] byteArray, int offset, int length) throws IOException {
+        indexOutputBuffer.writeBytes(byteArray, offset, length);
+    }
+
+    /**
+     * This method will return the file pointer to the current position in the stream.
+     *
+     */
+    @Override
+    public long getFilePointer() {
+        return indexOutputBuffer.getFilePointer();
+    }
+
+    /**
+     * This method will return checksum
+     *
+     */
+    @Override
+    public long getChecksum() throws IOException {
+        return indexOutputBuffer.getChecksum();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteBufferedOutputDirectory.java b/server/src/main/java/org/opensearch/index/store/RemoteBufferedOutputDirectory.java
new file mode 100644
index 0000000000000..b430ae2a6bc9c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteBufferedOutputDirectory.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.common.blobstore.BlobContainer;
+
+/**
+ * A {@code RemoteBufferedOutputDirectory} is an extension of RemoteDirectory which also provides an abstraction layer
+ * for storing a list of files to a remote store.
+ * Additionally, with this implementation, creation of new files is also allowed.
+ * A remoteDirectory contains only files (no sub-folder hierarchy).
+ *
+ * @opensearch.internal
+ */
+public class RemoteBufferedOutputDirectory extends RemoteDirectory {
+    public RemoteBufferedOutputDirectory(BlobContainer blobContainer) {
+        super(blobContainer);
+    }
+
+    @Override
+    public IndexOutput createOutput(String name, IOContext context) {
+        return new RemoteBufferedIndexOutput(name, this.blobContainer);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteDirectory.java b/server/src/main/java/org/opensearch/index/store/RemoteDirectory.java
new file mode 100644
index 0000000000000..eb75c39532d71
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteDirectory.java
@@ -0,0 +1,420 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.Lock;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.exception.CorruptFileException;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.RemoteTransferContainer;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeIndexInputStream;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeInputStream;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.store.exception.ChecksumCombinationException;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.NoSuchFileException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.UnaryOperator;
+import java.util.stream.Collectors;
+
+import static org.opensearch.common.blobstore.transfer.RemoteTransferContainer.checksumOfChecksum;
+
+/**
+ * A {@code RemoteDirectory} provides an abstraction layer for storing a list of files to a remote store.
+ * A remoteDirectory contains only files (no sub-folder hierarchy). This class does not support all the methods in
+ * the Directory interface. Currently, it contains implementation of methods which are used to copy files to/from
+ * the remote store. Implementation of remaining methods will be added as remote store is integrated with
+ * replication, peer recovery etc.
+ *
+ * @opensearch.internal
+ */
+public class RemoteDirectory extends Directory {
+
+    protected final BlobContainer blobContainer;
+    private static final Logger logger = LogManager.getLogger(RemoteDirectory.class);
+
+    private final UnaryOperator<OffsetRangeInputStream> uploadRateLimiter;
+
+    private final UnaryOperator<InputStream> downloadRateLimiter;
+
+    /**
+     * Number of bytes in the segment file to store checksum
+     */
+    private static final int SEGMENT_CHECKSUM_BYTES = 8;
+
+    public BlobContainer getBlobContainer() {
+        return blobContainer;
+    }
+
+    public RemoteDirectory(BlobContainer blobContainer) {
+        this(blobContainer, UnaryOperator.identity(), UnaryOperator.identity());
+    }
+
+    public RemoteDirectory(
+        BlobContainer blobContainer,
+        UnaryOperator<OffsetRangeInputStream> uploadRateLimiter,
+        UnaryOperator<InputStream> downloadRateLimiter
+    ) {
+        this.blobContainer = blobContainer;
+        this.uploadRateLimiter = uploadRateLimiter;
+        this.downloadRateLimiter = downloadRateLimiter;
+    }
+
+    /**
+     * Returns names of all files stored in this directory. The output must be in sorted (UTF-16,
+     * java's {@link String#compareTo}) order.
+     */
+    @Override
+    public String[] listAll() throws IOException {
+        return blobContainer.listBlobs().keySet().stream().sorted().toArray(String[]::new);
+    }
+
+    /**
+     * Returns names of files with given prefix in this directory.
+     * @param filenamePrefix The prefix to match against file names in the directory
+     * @return A list of the matching filenames in the directory
+     * @throws IOException if there were any failures in reading from the blob container
+     */
+    public Collection<String> listFilesByPrefix(String filenamePrefix) throws IOException {
+        return blobContainer.listBlobsByPrefix(filenamePrefix).keySet();
+    }
+
+    public List<String> listFilesByPrefixInLexicographicOrder(String filenamePrefix, int limit) throws IOException {
+        List<String> sortedBlobList = new ArrayList<>();
+        AtomicReference<Exception> exception = new AtomicReference<>();
+        final CountDownLatch latch = new CountDownLatch(1);
+        LatchedActionListener<List<BlobMetadata>> actionListener = new LatchedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(List<BlobMetadata> blobMetadata) {
+                sortedBlobList.addAll(blobMetadata.stream().map(BlobMetadata::name).collect(Collectors.toList()));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exception.set(e);
+            }
+        }, latch);
+
+        try {
+            blobContainer.listBlobsByPrefixInSortedOrder(
+                filenamePrefix,
+                limit,
+                BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC,
+                actionListener
+            );
+            latch.await();
+        } catch (InterruptedException e) {
+            throw new IOException("Exception in listFilesByPrefixInLexicographicOrder with prefix: " + filenamePrefix, e);
+        }
+        if (exception.get() != null) {
+            throw new IOException(exception.get());
+        } else {
+            return sortedBlobList;
+        }
+    }
+
+    /**
+     * Returns stream emitted from by blob object. Should be used with a closeable block.
+     *
+     * @param fileName Name of file
+     * @return Stream from the blob object
+     * @throws IOException if fetch of stream fails with IO error
+     */
+    public InputStream getBlobStream(String fileName) throws IOException {
+        return blobContainer.readBlob(fileName);
+    }
+
+    /**
+     * Removes an existing file in the directory.
+     *
+     * <p>This method will not throw an exception when the file doesn't exist and simply ignores this case.
+     * This is a deviation from the {@code Directory} interface where it is expected to throw either
+     * {@link NoSuchFileException} or {@link FileNotFoundException} if {@code name} points to a non-existing file.
+     *
+     * @param name the name of an existing file.
+     * @throws IOException if the file exists but could not be deleted.
+     */
+    @Override
+    public void deleteFile(String name) throws IOException {
+        // ToDo: Add a check for file existence
+        blobContainer.deleteBlobsIgnoringIfNotExists(Collections.singletonList(name));
+    }
+
+    /**
+     * Creates and returns a new instance of {@link RemoteIndexOutput} which will be used to copy files to the remote
+     * store.
+     *
+     * <p> In the {@link Directory} interface, it is expected to throw {@link java.nio.file.FileAlreadyExistsException}
+     * if the file already exists in the remote store. As this method does not open a file, it does not throw the
+     * exception.
+     *
+     * @param name the name of the file to copy to remote store.
+     */
+    @Override
+    public IndexOutput createOutput(String name, IOContext context) {
+        return new RemoteIndexOutput(name, blobContainer);
+    }
+
+    /**
+     * Opens a stream for reading an existing file and returns {@link RemoteIndexInput} enclosing the stream.
+     *
+     * @param name the name of an existing file.
+     * @throws IOException in case of I/O error
+     * @throws NoSuchFileException if the file does not exist
+     */
+    @Override
+    public IndexInput openInput(String name, IOContext context) throws IOException {
+        InputStream inputStream = null;
+        try {
+            inputStream = blobContainer.readBlob(name);
+            return new RemoteIndexInput(name, downloadRateLimiter.apply(inputStream), fileLength(name));
+        } catch (Exception e) {
+            // Incase the RemoteIndexInput creation fails, close the input stream to avoid file handler leak.
+            if (inputStream != null) {
+                try {
+                    inputStream.close();
+                } catch (Exception closeEx) {
+                    e.addSuppressed(closeEx);
+                }
+            }
+            logger.error("Exception while reading blob for file: " + name + " for path " + blobContainer.path());
+            throw e;
+        }
+    }
+
+    /**
+     * Closes the remote directory. Currently, it is a no-op.
+     * If remote directory maintains a state in future, we need to clean it before closing the directory
+     */
+    @Override
+    public void close() throws IOException {
+        // Do nothing
+    }
+
+    /**
+     * Returns the byte length of a file in the directory.
+     *
+     * @param name the name of an existing file.
+     * @throws IOException in case of I/O error
+     * @throws NoSuchFileException if the file does not exist
+     */
+    @Override
+    public long fileLength(String name) throws IOException {
+        // ToDo: Instead of calling remote store each time, keep a cache with segment metadata
+        Map<String, BlobMetadata> metadata = blobContainer.listBlobsByPrefix(name);
+        if (metadata.containsKey(name)) {
+            return metadata.get(name).length();
+        }
+        throw new NoSuchFileException(name);
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * Once soft deleting is supported segment files in the remote store, this method will provide details of
+     * number of files marked as deleted but not actually deleted from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public Set<String> getPendingDeletions() throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * Temporary IndexOutput is not required while working with Remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public IndexOutput createTempOutput(String prefix, String suffix, IOContext context) {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * Segment upload to the remote store will be permanent and does not require a separate sync API.
+     * This may change in the future if segment upload to remote store happens via cache and we need sync API to write
+     * the cache contents to the store permanently.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void sync(Collection<String> names) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * Once metadata to be stored with each shard is finalized, syncMetaData method will be used to sync the directory
+     * metadata to the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void syncMetaData() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * As this method is used by IndexWriter to publish commits, the implementation of this method is required when
+     * IndexWriter is backed by RemoteDirectory.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void rename(String source, String dest) throws IOException {
+        throw new UnsupportedOperationException();
+
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the directory unmodified.
+     * Once locking segment files in remote store is supported, implementation of this method is required with
+     * remote store specific LockFactory.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public Lock obtainLock(String name) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    public void delete() throws IOException {
+        blobContainer.delete();
+    }
+
+    public boolean copyFrom(
+        Directory from,
+        String src,
+        String remoteFileName,
+        IOContext context,
+        Runnable postUploadRunner,
+        ActionListener<Void> listener
+    ) {
+        if (blobContainer instanceof AsyncMultiStreamBlobContainer) {
+            try {
+                uploadBlob(from, src, remoteFileName, context, postUploadRunner, listener);
+            } catch (Exception e) {
+                listener.onFailure(e);
+            }
+            return true;
+        }
+        return false;
+    }
+
+    protected UnaryOperator<InputStream> getDownloadRateLimiter() {
+        return downloadRateLimiter;
+    }
+
+    private void uploadBlob(
+        Directory from,
+        String src,
+        String remoteFileName,
+        IOContext ioContext,
+        Runnable postUploadRunner,
+        ActionListener<Void> listener
+    ) throws Exception {
+        long expectedChecksum = calculateChecksumOfChecksum(from, src);
+        long contentLength;
+        try (IndexInput indexInput = from.openInput(src, ioContext)) {
+            contentLength = indexInput.length();
+        }
+        boolean remoteIntegrityEnabled = false;
+        if (getBlobContainer() instanceof AsyncMultiStreamBlobContainer) {
+            remoteIntegrityEnabled = ((AsyncMultiStreamBlobContainer) getBlobContainer()).remoteIntegrityCheckSupported();
+        }
+        RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+            src,
+            remoteFileName,
+            contentLength,
+            true,
+            WritePriority.NORMAL,
+            (size, position) -> uploadRateLimiter.apply(new OffsetRangeIndexInputStream(from.openInput(src, ioContext), size, position)),
+            expectedChecksum,
+            remoteIntegrityEnabled
+        );
+        ActionListener<Void> completionListener = ActionListener.wrap(resp -> {
+            try {
+                postUploadRunner.run();
+                listener.onResponse(null);
+            } catch (Exception e) {
+                logger.error(() -> new ParameterizedMessage("Exception in segment postUpload for file [{}]", src), e);
+                listener.onFailure(e);
+            }
+        }, ex -> {
+            logger.error(() -> new ParameterizedMessage("Failed to upload blob {}", src), ex);
+            IOException corruptIndexException = ExceptionsHelper.unwrapCorruption(ex);
+            if (corruptIndexException != null) {
+                listener.onFailure(corruptIndexException);
+                return;
+            }
+            Throwable throwable = ExceptionsHelper.unwrap(ex, CorruptFileException.class);
+            if (throwable != null) {
+                CorruptFileException corruptFileException = (CorruptFileException) throwable;
+                listener.onFailure(new CorruptIndexException(corruptFileException.getMessage(), corruptFileException.getFileName()));
+                return;
+            }
+            listener.onFailure(ex);
+        });
+
+        completionListener = ActionListener.runBefore(completionListener, () -> {
+            try {
+                remoteTransferContainer.close();
+            } catch (Exception e) {
+                logger.warn("Error occurred while closing streams", e);
+            }
+        });
+
+        WriteContext writeContext = remoteTransferContainer.createWriteContext();
+        ((AsyncMultiStreamBlobContainer) blobContainer).asyncBlobUpload(writeContext, completionListener);
+    }
+
+    private long calculateChecksumOfChecksum(Directory directory, String file) throws IOException {
+        try (IndexInput indexInput = directory.openInput(file, IOContext.DEFAULT)) {
+            try {
+                return checksumOfChecksum(indexInput, SEGMENT_CHECKSUM_BYTES);
+            } catch (Exception e) {
+                throw new ChecksumCombinationException(
+                    "Potentially corrupted file: Checksum combination failed while combining stored checksum "
+                        + "and calculated checksum of stored checksum in segment file: "
+                        + file
+                        + ", directory: "
+                        + directory,
+                    file,
+                    e
+                );
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteIndexInput.java b/server/src/main/java/org/opensearch/index/store/RemoteIndexInput.java
new file mode 100644
index 0000000000000..2c809563ca961
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteIndexInput.java
@@ -0,0 +1,103 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.IndexInput;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Class for input from a file in a {@link RemoteDirectory}. Used for all input operations from the remote store.
+ * Currently, only methods from {@link IndexInput} that are required for reading a file from remote store are
+ * implemented. Remaining methods will be implemented as we open up remote store for other use cases like replication,
+ * peer recovery etc.
+ * ToDo: Extend ChecksumIndexInput
+ * @see RemoteDirectory
+ *
+ * @opensearch.internal
+ */
+public class RemoteIndexInput extends IndexInput {
+
+    private final InputStream inputStream;
+    private final long size;
+    private long filePointer;
+
+    public RemoteIndexInput(String name, InputStream inputStream, long size) {
+        super(name);
+        this.inputStream = inputStream;
+        this.size = size;
+        this.filePointer = 0;
+    }
+
+    @Override
+    public byte readByte() throws IOException {
+        byte[] buffer = new byte[1];
+        int numberOfBytesRead = inputStream.read(buffer);
+        if (numberOfBytesRead != -1) {
+            filePointer += numberOfBytesRead;
+        }
+        return buffer[0];
+    }
+
+    @Override
+    public void readBytes(byte[] b, int offset, int len) throws IOException {
+        int bytesRead = inputStream.read(b, offset, len);
+        if (bytesRead == len) {
+            filePointer += bytesRead;
+        } else {
+            while (bytesRead > 0 && bytesRead < len) {
+                filePointer += bytesRead;
+                len -= bytesRead;
+                offset += bytesRead;
+                bytesRead = inputStream.read(b, offset, len);
+            }
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        inputStream.close();
+    }
+
+    @Override
+    public long length() {
+        return size;
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexInput unmodified.
+     * This method is not implemented as it is not used for the file transfer to/from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void seek(long pos) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Returns the current position in this file in terms of number of bytes read so far.
+     */
+    @Override
+    public long getFilePointer() {
+        return filePointer;
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexInput unmodified.
+     * This method is not implemented as it is not used for the file transfer to/from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public IndexInput slice(String sliceDescription, long offset, long length) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteIndexOutput.java b/server/src/main/java/org/opensearch/index/store/RemoteIndexOutput.java
new file mode 100644
index 0000000000000..11ea223f529f2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteIndexOutput.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.DataInput;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.lucene.store.InputStreamIndexInput;
+
+import java.io.IOException;
+
+/**
+ * Class for output to a file in a {@link RemoteDirectory}. Used for all output operations to the remote store.
+ * Currently, only methods from {@link IndexOutput} that are required for uploading a segment file to remote store are
+ * implemented. Remaining methods will be implemented as we open up remote store for other use cases like replication,
+ * peer recovery etc.
+ * ToDo: Extend ChecksumIndexInput
+ * @see RemoteDirectory
+ *
+ * @opensearch.internal
+ */
+public class RemoteIndexOutput extends IndexOutput {
+
+    protected final BlobContainer blobContainer;
+
+    public RemoteIndexOutput(String name, BlobContainer blobContainer) {
+        super(name, name);
+        this.blobContainer = blobContainer;
+    }
+
+    @Override
+    public void copyBytes(DataInput input, long numBytes) throws IOException {
+        assert input instanceof IndexInput : "input should be instance of IndexInput";
+        blobContainer.writeBlob(getName(), new InputStreamIndexInput((IndexInput) input, numBytes), numBytes, false);
+    }
+
+    /**
+     * This is a no-op. Once segment file upload to the remote store is complete, we don't need to explicitly close
+     * the stream. It is taken care by internal APIs of client of the remote store.
+     */
+    @Override
+    public void close() throws IOException {
+        // do nothing
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexOutput unmodified.
+     * This method is not implemented as it is not used for the file transfer to/from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void writeByte(byte b) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexOutput unmodified.
+     * This method is not implemented as it is not used for the file transfer to/from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public void writeBytes(byte[] byteArray, int offset, int length) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexOutput unmodified.
+     * This method is not implemented as it is not used for the file transfer to/from the remote store.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public long getFilePointer() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Guaranteed to throw an exception and leave the RemoteIndexOutput unmodified.
+     * This method is not implemented as it is not directly used for the file transfer to/from the remote store.
+     * But the checksum is important to verify integrity of the data and that means implementing this method will
+     * be required for the segment upload as well.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    @Override
+    public long getChecksum() throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectory.java b/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectory.java
new file mode 100644
index 0000000000000..a97b22360716c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectory.java
@@ -0,0 +1,919 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.SegmentCommitInfo;
+import org.apache.lucene.index.SegmentInfo;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.ByteBuffersDataOutput;
+import org.apache.lucene.store.ByteBuffersIndexOutput;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.util.Version;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.stream.read.listener.ReadContextListener;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.io.VersionedCodecStreamWrapper;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.index.store.lockmanager.FileLockInfo;
+import org.opensearch.index.store.lockmanager.RemoteStoreCommitLevelLockManager;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManager;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadataHandler;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+/**
+ * A RemoteDirectory extension for remote segment store. We need to make sure we don't overwrite a segment file once uploaded.
+ * In order to prevent segment overwrite which can occur due to two primary nodes for the same shard at the same time,
+ * a unique suffix is added to the uploaded segment file. This class keeps track of filename of segments stored
+ * in remote segment store vs filename in local filesystem and provides the consistent Directory interface so that
+ * caller will be accessing segment files in the same way as {@code FSDirectory}. Apart from storing actual segment files,
+ * remote segment store also keeps track of refresh checkpoints as metadata in a separate path which is handled by
+ * another instance of {@code RemoteDirectory}.
+ *
+ * @opensearch.internal
+ */
+public final class RemoteSegmentStoreDirectory extends FilterDirectory implements RemoteStoreCommitLevelLockManager {
+
+    /**
+     * Each segment file is uploaded with unique suffix.
+     * For example, _0.cfe in local filesystem will be uploaded to remote segment store as _0.cfe__gX7bNIIBrs0AUNsR2yEG
+     */
+    public static final String SEGMENT_NAME_UUID_SEPARATOR = "__";
+
+    /**
+     * remoteDataDirectory is used to store segment files at path: cluster_UUID/index_UUID/shardId/segments/data
+     */
+    private final RemoteDirectory remoteDataDirectory;
+    /**
+     * remoteMetadataDirectory is used to store metadata files at path: cluster_UUID/index_UUID/shardId/segments/metadata
+     */
+    private final RemoteDirectory remoteMetadataDirectory;
+
+    private final RemoteStoreLockManager mdLockManager;
+
+    private final ThreadPool threadPool;
+
+    private final RecoverySettings recoverySettings;
+
+    /**
+     * Keeps track of local segment filename to uploaded filename along with other attributes like checksum.
+     * This map acts as a cache layer for uploaded segment filenames which helps avoid calling listAll() each time.
+     * It is important to initialize this map on creation of RemoteSegmentStoreDirectory and update it on each upload and delete.
+     */
+    private Map<String, UploadedSegmentMetadata> segmentsUploadedToRemoteStore;
+
+    private static final VersionedCodecStreamWrapper<RemoteSegmentMetadata> metadataStreamWrapper = new VersionedCodecStreamWrapper<>(
+        new RemoteSegmentMetadataHandler(),
+        RemoteSegmentMetadata.CURRENT_VERSION,
+        RemoteSegmentMetadata.METADATA_CODEC
+    );
+
+    private static final Logger staticLogger = LogManager.getLogger(RemoteSegmentStoreDirectory.class);
+
+    private final Logger logger;
+
+    /**
+     * AtomicBoolean that ensures only one staleCommitDeletion activity is scheduled at a time.
+     * Visible for testing
+     */
+    protected final AtomicBoolean canDeleteStaleCommits = new AtomicBoolean(true);
+
+    private final AtomicLong metadataUploadCounter = new AtomicLong(0);
+
+    public static final int METADATA_FILES_TO_FETCH = 10;
+
+    public RemoteSegmentStoreDirectory(
+        RemoteDirectory remoteDataDirectory,
+        RemoteDirectory remoteMetadataDirectory,
+        RemoteStoreLockManager mdLockManager,
+        ThreadPool threadPool,
+        ShardId shardId,
+        RecoverySettings recoverySettings
+    ) throws IOException {
+        super(remoteDataDirectory);
+        this.remoteDataDirectory = remoteDataDirectory;
+        this.remoteMetadataDirectory = remoteMetadataDirectory;
+        this.mdLockManager = mdLockManager;
+        this.threadPool = threadPool;
+        this.recoverySettings = recoverySettings;
+        this.logger = Loggers.getLogger(getClass(), shardId);
+        init();
+    }
+
+    /**
+     * Initializes the cache which keeps track of all the segment files uploaded to the remote segment store.
+     * As this cache is specific to an instance of RemoteSegmentStoreDirectory, it is possible that cache becomes stale
+     * if another instance of RemoteSegmentStoreDirectory is used to upload/delete segment files.
+     * It is caller's responsibility to call init() again to ensure that cache is properly updated.
+     *
+     * @throws IOException if there were any failures in reading the metadata file
+     */
+    public RemoteSegmentMetadata init() throws IOException {
+        logger.debug("Start initialisation of remote segment metadata");
+        RemoteSegmentMetadata remoteSegmentMetadata = readLatestMetadataFile();
+        if (remoteSegmentMetadata != null) {
+            this.segmentsUploadedToRemoteStore = new ConcurrentHashMap<>(remoteSegmentMetadata.getMetadata());
+        } else {
+            this.segmentsUploadedToRemoteStore = new ConcurrentHashMap<>();
+        }
+        logger.debug("Initialisation of remote segment metadata completed");
+        return remoteSegmentMetadata;
+    }
+
+    /**
+     * Initializes the cache to a specific commit which keeps track of all the segment files uploaded to the
+     * remote segment store.
+     * this is currently used to restore snapshots, where we want to copy segment files from a given commit.
+     * TODO: check if we can return read only RemoteSegmentStoreDirectory object from here.
+     *
+     * @throws IOException if there were any failures in reading the metadata file
+     */
+    public RemoteSegmentMetadata initializeToSpecificCommit(long primaryTerm, long commitGeneration) throws IOException {
+        String metadataFile = getMetadataFileForCommit(primaryTerm, commitGeneration);
+        RemoteSegmentMetadata remoteSegmentMetadata = readMetadataFile(metadataFile);
+        if (remoteSegmentMetadata != null) {
+            this.segmentsUploadedToRemoteStore = new ConcurrentHashMap<>(remoteSegmentMetadata.getMetadata());
+        } else {
+            this.segmentsUploadedToRemoteStore = new ConcurrentHashMap<>();
+        }
+        return remoteSegmentMetadata;
+    }
+
+    /**
+     * Read the latest metadata file to get the list of segments uploaded to the remote segment store.
+     * We upload a metadata file per refresh, but it is not unique per refresh. Refresh metadata file is unique for a given commit.
+     * The format of refresh metadata filename is: refresh_metadata__PrimaryTerm__Generation__UUID
+     * Refresh metadata files keep track of active segments for the shard at the time of refresh.
+     * In order to get the list of segment files uploaded to the remote segment store, we need to read the latest metadata file.
+     * Each metadata file contains a map where
+     * Key is - Segment local filename and
+     * Value is - local filename::uploaded filename::checksum
+     *
+     * @return Map of segment filename to uploaded filename with checksum
+     * @throws IOException if there were any failures in reading the metadata file
+     */
+    public RemoteSegmentMetadata readLatestMetadataFile() throws IOException {
+        RemoteSegmentMetadata remoteSegmentMetadata = null;
+
+        List<String> metadataFiles = remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+            MetadataFilenameUtils.METADATA_PREFIX,
+            METADATA_FILES_TO_FETCH
+        );
+
+        RemoteStoreUtils.verifyNoMultipleWriters(metadataFiles, MetadataFilenameUtils::getNodeIdByPrimaryTermAndGen);
+
+        if (metadataFiles.isEmpty() == false) {
+            String latestMetadataFile = metadataFiles.get(0);
+            logger.trace("Reading latest Metadata file {}", latestMetadataFile);
+            remoteSegmentMetadata = readMetadataFile(latestMetadataFile);
+        } else {
+            logger.trace("No metadata file found, this can happen for new index with no data uploaded to remote segment store");
+        }
+
+        return remoteSegmentMetadata;
+    }
+
+    private RemoteSegmentMetadata readMetadataFile(String metadataFilename) throws IOException {
+        try (InputStream inputStream = remoteMetadataDirectory.getBlobStream(metadataFilename)) {
+            byte[] metadataBytes = inputStream.readAllBytes();
+            return metadataStreamWrapper.readStream(new ByteArrayIndexInput(metadataFilename, metadataBytes));
+        }
+    }
+
+    /**
+     * Metadata of a segment that is uploaded to remote segment store.
+     */
+    public static class UploadedSegmentMetadata {
+        // Visible for testing
+        static final String SEPARATOR = "::";
+
+        private final String originalFilename;
+        private final String uploadedFilename;
+        private final String checksum;
+        private final long length;
+
+        /**
+         * The Lucene major version that wrote the original segment files.
+         * As part of the Lucene version compatibility check, this version information stored in the metadata
+         * will be used to skip downloading the segment files unnecessarily
+         * if they were written by an incompatible Lucene version.
+         */
+        private int writtenByMajor;
+
+        UploadedSegmentMetadata(String originalFilename, String uploadedFilename, String checksum, long length) {
+            this.originalFilename = originalFilename;
+            this.uploadedFilename = uploadedFilename;
+            this.checksum = checksum;
+            this.length = length;
+        }
+
+        @Override
+        public String toString() {
+            return String.join(
+                SEPARATOR,
+                originalFilename,
+                uploadedFilename,
+                checksum,
+                String.valueOf(length),
+                String.valueOf(writtenByMajor)
+            );
+        }
+
+        public String getChecksum() {
+            return this.checksum;
+        }
+
+        public long getLength() {
+            return this.length;
+        }
+
+        public static UploadedSegmentMetadata fromString(String uploadedFilename) {
+            String[] values = uploadedFilename.split(SEPARATOR);
+            UploadedSegmentMetadata metadata = new UploadedSegmentMetadata(values[0], values[1], values[2], Long.parseLong(values[3]));
+            if (values.length < 5) {
+                staticLogger.error("Lucene version is missing for UploadedSegmentMetadata: " + uploadedFilename);
+            }
+
+            metadata.setWrittenByMajor(Integer.parseInt(values[4]));
+
+            return metadata;
+        }
+
+        public String getOriginalFilename() {
+            return originalFilename;
+        }
+
+        public void setWrittenByMajor(int writtenByMajor) {
+            if (writtenByMajor <= Version.LATEST.major && writtenByMajor >= Version.MIN_SUPPORTED_MAJOR) {
+                this.writtenByMajor = writtenByMajor;
+            } else {
+                throw new IllegalArgumentException(
+                    "Lucene major version supplied ("
+                        + writtenByMajor
+                        + ") is incorrect. Should be between Version.LATEST ("
+                        + Version.LATEST.major
+                        + ") and Version.MIN_SUPPORTED_MAJOR ("
+                        + Version.MIN_SUPPORTED_MAJOR
+                        + ")."
+                );
+            }
+        }
+    }
+
+    /**
+     * Contains utility methods that provide various parts of metadata filename along with comparator
+     * Each metadata filename is of format: PREFIX__PrimaryTerm__Generation__UUID
+     */
+    public static class MetadataFilenameUtils {
+        public static final String SEPARATOR = "__";
+        public static final String METADATA_PREFIX = "metadata";
+
+        static String getMetadataFilePrefixForCommit(long primaryTerm, long generation) {
+            return String.join(
+                SEPARATOR,
+                METADATA_PREFIX,
+                RemoteStoreUtils.invertLong(primaryTerm),
+                RemoteStoreUtils.invertLong(generation)
+            );
+        }
+
+        // Visible for testing
+        public static String getMetadataFilename(
+            long primaryTerm,
+            long generation,
+            long translogGeneration,
+            long uploadCounter,
+            int metadataVersion,
+            String nodeId
+        ) {
+            return String.join(
+                SEPARATOR,
+                METADATA_PREFIX,
+                RemoteStoreUtils.invertLong(primaryTerm),
+                RemoteStoreUtils.invertLong(generation),
+                RemoteStoreUtils.invertLong(translogGeneration),
+                RemoteStoreUtils.invertLong(uploadCounter),
+                nodeId,
+                RemoteStoreUtils.invertLong(System.currentTimeMillis()),
+                String.valueOf(metadataVersion)
+            );
+        }
+
+        // Visible for testing
+        static long getPrimaryTerm(String[] filenameTokens) {
+            return RemoteStoreUtils.invertLong(filenameTokens[1]);
+        }
+
+        // Visible for testing
+        static long getGeneration(String[] filenameTokens) {
+            return RemoteStoreUtils.invertLong(filenameTokens[2]);
+        }
+
+        public static Tuple<String, String> getNodeIdByPrimaryTermAndGen(String filename) {
+            String[] tokens = filename.split(SEPARATOR);
+            if (tokens.length < 8) {
+                // For versions < 2.11, we don't have node id.
+                return null;
+            }
+            String primaryTermAndGen = String.join(SEPARATOR, tokens[1], tokens[2], tokens[3]);
+
+            String nodeId = tokens[5];
+            return new Tuple<>(primaryTermAndGen, nodeId);
+        }
+
+    }
+
+    /**
+     * Returns list of all the segment files uploaded to remote segment store till the last refresh checkpoint.
+     * Any segment file that is uploaded without corresponding metadata file will not be visible as part of listAll().
+     * We chose not to return cache entries for listAll as cache can have entries for stale segments as well.
+     * Even if we plan to delete stale segments from remote segment store, it will be a periodic operation.
+     *
+     * @return segment filenames stored in remote segment store
+     * @throws IOException if there were any failures in reading the metadata file
+     */
+    @Override
+    public String[] listAll() throws IOException {
+        return readLatestMetadataFile().getMetadata().keySet().toArray(new String[0]);
+    }
+
+    /**
+     * Delete segment file from remote segment store.
+     *
+     * @param name the name of an existing segment file in local filesystem.
+     * @throws IOException if the file exists but could not be deleted.
+     */
+    @Override
+    public void deleteFile(String name) throws IOException {
+        String remoteFilename = getExistingRemoteFilename(name);
+        if (remoteFilename != null) {
+            remoteDataDirectory.deleteFile(remoteFilename);
+            segmentsUploadedToRemoteStore.remove(name);
+        }
+    }
+
+    /**
+     * Returns the byte length of a segment file in the remote segment store.
+     *
+     * @param name the name of an existing segment file in local filesystem.
+     * @throws IOException         in case of I/O error
+     * @throws NoSuchFileException if the file does not exist in the cache or remote segment store
+     */
+    @Override
+    public long fileLength(String name) throws IOException {
+        if (segmentsUploadedToRemoteStore.containsKey(name)) {
+            return segmentsUploadedToRemoteStore.get(name).getLength();
+        }
+        String remoteFilename = getExistingRemoteFilename(name);
+        if (remoteFilename != null) {
+            return remoteDataDirectory.fileLength(remoteFilename);
+        } else {
+            throw new NoSuchFileException(name);
+        }
+    }
+
+    /**
+     * Creates and returns a new instance of {@link RemoteIndexOutput} which will be used to copy files to the remote
+     * segment store.
+     *
+     * @param name the name of the file to create.
+     * @throws IOException in case of I/O error
+     */
+    @Override
+    public IndexOutput createOutput(String name, IOContext context) throws IOException {
+        return remoteDataDirectory.createOutput(getNewRemoteSegmentFilename(name), context);
+    }
+
+    /**
+     * Opens a stream for reading an existing file and returns {@link RemoteIndexInput} enclosing the stream.
+     *
+     * @param name the name of an existing file.
+     * @throws IOException         in case of I/O error
+     * @throws NoSuchFileException if the file does not exist either in cache or remote segment store
+     */
+    @Override
+    public IndexInput openInput(String name, IOContext context) throws IOException {
+        String remoteFilename = getExistingRemoteFilename(name);
+        if (remoteFilename != null) {
+            return remoteDataDirectory.openInput(remoteFilename, context);
+        } else {
+            throw new NoSuchFileException(name);
+        }
+    }
+
+    /**
+     * Copies a file from the source directory to a remote based on multi-stream upload support.
+     * If vendor plugin supports uploading multiple parts in parallel, <code>BlobContainer#writeBlobByStreams</code>
+     * will be used, else, the legacy {@link RemoteSegmentStoreDirectory#copyFrom(Directory, String, String, IOContext)}
+     * will be called.
+     *
+     * @param from     The directory for the file to be uploaded
+     * @param src      File to be uploaded
+     * @param context  IOContext to be used to open IndexInput of file during remote upload
+     * @param listener Listener to handle upload callback events
+     */
+    public void copyFrom(Directory from, String src, IOContext context, ActionListener<Void> listener) {
+        try {
+            final String remoteFileName = getNewRemoteSegmentFilename(src);
+            boolean uploaded = remoteDataDirectory.copyFrom(from, src, remoteFileName, context, () -> {
+                try {
+                    postUpload(from, src, remoteFileName, getChecksumOfLocalFile(from, src));
+                } catch (IOException e) {
+                    throw new RuntimeException("Exception in segment postUpload for file " + src, e);
+                }
+            }, listener);
+            if (uploaded == false) {
+                copyFrom(from, src, src, context);
+                listener.onResponse(null);
+            }
+        } catch (Exception e) {
+            logger.warn(() -> new ParameterizedMessage("Exception while uploading file {} to the remote segment store", src), e);
+            listener.onFailure(e);
+        }
+    }
+
+    /**
+     * Copies an existing {@code source} file from this directory to a non-existent file (also
+     * named {@code source}) in either {@code destinationDirectory} or {@code destinationPath}.
+     * If the blob container backing this directory supports multipart downloads, the {@code source}
+     * file will be downloaded (potentially in multiple concurrent parts) directly to
+     * {@code destinationPath}. This method will return immediately and {@code fileCompletionListener}
+     * will be notified upon completion.
+     * <p>
+     * If multipart downloads are not supported, then {@code source} file will be copied to a file named
+     * {@code source} in a single part to {@code destinationDirectory}. The download will happen on the
+     * calling thread and {@code fileCompletionListener} will be notified synchronously before this
+     * method returns.
+     *
+     * @param source The source file name
+     * @param destinationDirectory The destination directory (if multipart is not supported)
+     * @param destinationPath The destination path (if multipart is supported)
+     * @param fileCompletionListener The listener to notify of completion
+     */
+    public void copyTo(String source, Directory destinationDirectory, Path destinationPath, ActionListener<String> fileCompletionListener) {
+        final String blobName = getExistingRemoteFilename(source);
+        if (destinationPath != null && remoteDataDirectory.getBlobContainer() instanceof AsyncMultiStreamBlobContainer) {
+            final AsyncMultiStreamBlobContainer blobContainer = (AsyncMultiStreamBlobContainer) remoteDataDirectory.getBlobContainer();
+            final Path destinationFilePath = destinationPath.resolve(source);
+            final ReadContextListener readContextListener = new ReadContextListener(
+                blobName,
+                destinationFilePath,
+                fileCompletionListener,
+                threadPool,
+                remoteDataDirectory.getDownloadRateLimiter(),
+                recoverySettings.getMaxConcurrentRemoteStoreStreams()
+            );
+            blobContainer.readBlobAsync(blobName, readContextListener);
+        } else {
+            // Fallback to older mechanism of downloading the file
+            try {
+                destinationDirectory.copyFrom(this, source, source, IOContext.DEFAULT);
+                fileCompletionListener.onResponse(source);
+            } catch (IOException e) {
+                fileCompletionListener.onFailure(e);
+            }
+        }
+    }
+
+    /**
+     * This acquires a lock on a given commit by creating a lock file in lock directory using {@code FileLockInfo}
+     *
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation  Commit Generation
+     * @param acquirerId  Lock Acquirer ID which wants to acquire lock on the commit.
+     * @throws IOException         will be thrown in case i) listing file failed or ii) Writing the lock file failed.
+     * @throws NoSuchFileException when metadata file is not present for given commit point.
+     */
+    @Override
+    public void acquireLock(long primaryTerm, long generation, String acquirerId) throws IOException {
+        String metadataFile = getMetadataFileForCommit(primaryTerm, generation);
+        mdLockManager.acquire(FileLockInfo.getLockInfoBuilder().withFileToLock(metadataFile).withAcquirerId(acquirerId).build());
+    }
+
+    /**
+     * Releases a lock which was acquired on given segment commit.
+     *
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation  Commit Generation
+     * @param acquirerId  Acquirer ID for which lock needs to be released.
+     * @throws IOException         will be thrown in case i) listing lock files failed or ii) deleting the lock file failed.
+     * @throws NoSuchFileException when metadata file is not present for given commit point.
+     */
+    @Override
+    public void releaseLock(long primaryTerm, long generation, String acquirerId) throws IOException {
+        String metadataFile = getMetadataFileForCommit(primaryTerm, generation);
+        mdLockManager.release(FileLockInfo.getLockInfoBuilder().withFileToLock(metadataFile).withAcquirerId(acquirerId).build());
+    }
+
+    /**
+     * Checks if a specific commit have any corresponding lock file.
+     *
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation  Commit Generation
+     * @return True if there is at least one lock for given primary term and generation.
+     * @throws IOException         will be thrown in case listing lock files failed.
+     * @throws NoSuchFileException when metadata file is not present for given commit point.
+     */
+    @Override
+    public Boolean isLockAcquired(long primaryTerm, long generation) throws IOException {
+        String metadataFile = getMetadataFileForCommit(primaryTerm, generation);
+        return isLockAcquired(metadataFile);
+    }
+
+    // Visible for testing
+    Boolean isLockAcquired(String metadataFile) throws IOException {
+        return mdLockManager.isAcquired(FileLockInfo.getLockInfoBuilder().withFileToLock(metadataFile).build());
+    }
+
+    // Visible for testing
+    String getMetadataFileForCommit(long primaryTerm, long generation) throws IOException {
+        List<String> metadataFiles = remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+            MetadataFilenameUtils.getMetadataFilePrefixForCommit(primaryTerm, generation),
+            1
+        );
+
+        if (metadataFiles.isEmpty()) {
+            throw new NoSuchFileException(
+                "Metadata file is not present for given primary term " + primaryTerm + " and generation " + generation
+            );
+        }
+        if (metadataFiles.size() != 1) {
+            throw new IllegalStateException(
+                "there should be only one metadata file for given primary term "
+                    + primaryTerm
+                    + "and generation "
+                    + generation
+                    + " but found "
+                    + metadataFiles.size()
+            );
+        }
+        return metadataFiles.get(0);
+    }
+
+    private void postUpload(Directory from, String src, String remoteFilename, String checksum) throws IOException {
+        UploadedSegmentMetadata segmentMetadata = new UploadedSegmentMetadata(src, remoteFilename, checksum, from.fileLength(src));
+        segmentsUploadedToRemoteStore.put(src, segmentMetadata);
+    }
+
+    /**
+     * Copies an existing src file from directory from to a non-existent file dest in this directory.
+     * Once the segment is uploaded to remote segment store, update the cache accordingly.
+     */
+    @Override
+    public void copyFrom(Directory from, String src, String dest, IOContext context) throws IOException {
+        String remoteFilename = getNewRemoteSegmentFilename(dest);
+        remoteDataDirectory.copyFrom(from, src, remoteFilename, context);
+        postUpload(from, src, remoteFilename, getChecksumOfLocalFile(from, src));
+    }
+
+    /**
+     * Checks if the file exists in the uploadedSegments cache and the checksum matches.
+     * It is important to match the checksum as the same segment filename can be used for different
+     * segments due to a concurrency issue.
+     *
+     * @param localFilename filename of segment stored in local filesystem
+     * @param checksum      checksum of the segment file
+     * @return true if file exists in cache and checksum matches.
+     */
+    public boolean containsFile(String localFilename, String checksum) {
+        return segmentsUploadedToRemoteStore.containsKey(localFilename)
+            && segmentsUploadedToRemoteStore.get(localFilename).checksum.equals(checksum);
+    }
+
+    /**
+     * Upload metadata file
+     *
+     * @param segmentFiles         segment files that are part of the shard at the time of the latest refresh
+     * @param segmentInfosSnapshot SegmentInfos bytes to store as part of metadata file
+     * @param storeDirectory instance of local directory to temporarily create metadata file before upload
+     * @param translogGeneration translog generation
+     * @param replicationCheckpoint ReplicationCheckpoint of primary shard
+     * @param nodeId node id
+     * @throws IOException in case of I/O error while uploading the metadata file
+     */
+    public void uploadMetadata(
+        Collection<String> segmentFiles,
+        SegmentInfos segmentInfosSnapshot,
+        Directory storeDirectory,
+        long translogGeneration,
+        ReplicationCheckpoint replicationCheckpoint,
+        String nodeId
+    ) throws IOException {
+        synchronized (this) {
+            String metadataFilename = MetadataFilenameUtils.getMetadataFilename(
+                replicationCheckpoint.getPrimaryTerm(),
+                segmentInfosSnapshot.getGeneration(),
+                translogGeneration,
+                metadataUploadCounter.incrementAndGet(),
+                RemoteSegmentMetadata.CURRENT_VERSION,
+                nodeId
+            );
+            try {
+                try (IndexOutput indexOutput = storeDirectory.createOutput(metadataFilename, IOContext.DEFAULT)) {
+                    Map<String, Integer> segmentToLuceneVersion = getSegmentToLuceneVersion(segmentFiles, segmentInfosSnapshot);
+                    Map<String, String> uploadedSegments = new HashMap<>();
+                    for (String file : segmentFiles) {
+                        if (segmentsUploadedToRemoteStore.containsKey(file)) {
+                            UploadedSegmentMetadata metadata = segmentsUploadedToRemoteStore.get(file);
+                            metadata.setWrittenByMajor(segmentToLuceneVersion.get(metadata.originalFilename));
+                            uploadedSegments.put(file, metadata.toString());
+                        } else {
+                            throw new NoSuchFileException(file);
+                        }
+                    }
+
+                    ByteBuffersDataOutput byteBuffersIndexOutput = new ByteBuffersDataOutput();
+                    segmentInfosSnapshot.write(
+                        new ByteBuffersIndexOutput(byteBuffersIndexOutput, "Snapshot of SegmentInfos", "SegmentInfos")
+                    );
+                    byte[] segmentInfoSnapshotByteArray = byteBuffersIndexOutput.toArrayCopy();
+
+                    metadataStreamWrapper.writeStream(
+                        indexOutput,
+                        new RemoteSegmentMetadata(
+                            RemoteSegmentMetadata.fromMapOfStrings(uploadedSegments),
+                            segmentInfoSnapshotByteArray,
+                            replicationCheckpoint
+                        )
+                    );
+                }
+                storeDirectory.sync(Collections.singleton(metadataFilename));
+                remoteMetadataDirectory.copyFrom(storeDirectory, metadataFilename, metadataFilename, IOContext.DEFAULT);
+            } finally {
+                tryAndDeleteLocalFile(metadataFilename, storeDirectory);
+            }
+        }
+    }
+
+    /**
+     * Parses the provided SegmentInfos to retrieve a mapping of the provided segment files to
+     * the respective Lucene major version that wrote the segments
+     *
+     * @param segmentFiles         List of segment files for which the Lucene major version is needed
+     * @param segmentInfosSnapshot SegmentInfos instance to parse
+     * @return Map of the segment file to its Lucene major version
+     */
+    private Map<String, Integer> getSegmentToLuceneVersion(Collection<String> segmentFiles, SegmentInfos segmentInfosSnapshot) {
+        Map<String, Integer> segmentToLuceneVersion = new HashMap<>();
+        for (SegmentCommitInfo segmentCommitInfo : segmentInfosSnapshot) {
+            SegmentInfo info = segmentCommitInfo.info;
+            Set<String> segFiles = info.files();
+            for (String file : segFiles) {
+                segmentToLuceneVersion.put(file, info.getVersion().major);
+            }
+        }
+
+        for (String file : segmentFiles) {
+            if (segmentToLuceneVersion.containsKey(file) == false) {
+                if (file.equals(segmentInfosSnapshot.getSegmentsFileName())) {
+                    segmentToLuceneVersion.put(file, segmentInfosSnapshot.getCommitLuceneVersion().major);
+                } else {
+                    // Fallback to the Lucene major version of the respective segment's .si file
+                    String segmentInfoFileName = RemoteStoreUtils.getSegmentName(file) + ".si";
+                    segmentToLuceneVersion.put(file, segmentToLuceneVersion.get(segmentInfoFileName));
+                }
+            }
+        }
+
+        return segmentToLuceneVersion;
+    }
+
+    /**
+     * Try to delete file from local store. Fails silently on failures
+     *
+     * @param filename: name of the file to be deleted
+     */
+    private void tryAndDeleteLocalFile(String filename, Directory directory) {
+        try {
+            logger.debug("Deleting file: " + filename);
+            directory.deleteFile(filename);
+        } catch (NoSuchFileException | FileNotFoundException e) {
+            logger.trace("Exception while deleting. Missing file : " + filename, e);
+        } catch (IOException e) {
+            logger.warn("Exception while deleting: " + filename, e);
+        }
+    }
+
+    private String getChecksumOfLocalFile(Directory directory, String file) throws IOException {
+        try (IndexInput indexInput = directory.openInput(file, IOContext.DEFAULT)) {
+            return Long.toString(CodecUtil.retrieveChecksum(indexInput));
+        }
+    }
+
+    private String getExistingRemoteFilename(String localFilename) {
+        if (segmentsUploadedToRemoteStore.containsKey(localFilename)) {
+            return segmentsUploadedToRemoteStore.get(localFilename).uploadedFilename;
+        } else {
+            return null;
+        }
+    }
+
+    private String getNewRemoteSegmentFilename(String localFilename) {
+        return localFilename + SEGMENT_NAME_UUID_SEPARATOR + UUIDs.base64UUID();
+    }
+
+    private String getLocalSegmentFilename(String remoteFilename) {
+        return remoteFilename.split(SEGMENT_NAME_UUID_SEPARATOR)[0];
+    }
+
+    // Visible for testing
+    public Map<String, UploadedSegmentMetadata> getSegmentsUploadedToRemoteStore() {
+        return Collections.unmodifiableMap(this.segmentsUploadedToRemoteStore);
+    }
+
+    /**
+     * Delete stale segment and metadata files
+     * One metadata file is kept per commit (refresh updates the same file). To read segments uploaded to remote store,
+     * we just need to read the latest metadata file. All the stale metadata files can be safely deleted.
+     *
+     * @param lastNMetadataFilesToKeep number of metadata files to keep
+     * @throws IOException in case of I/O error while reading from / writing to remote segment store
+     */
+    public void deleteStaleSegments(int lastNMetadataFilesToKeep) throws IOException {
+        List<String> sortedMetadataFileList = remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+            MetadataFilenameUtils.METADATA_PREFIX,
+            Integer.MAX_VALUE
+        );
+        if (sortedMetadataFileList.size() <= lastNMetadataFilesToKeep) {
+            logger.debug(
+                "Number of commits in remote segment store={}, lastNMetadataFilesToKeep={}",
+                sortedMetadataFileList.size(),
+                lastNMetadataFilesToKeep
+            );
+            return;
+        }
+
+        List<String> metadataFilesEligibleToDelete = sortedMetadataFileList.subList(
+            lastNMetadataFilesToKeep,
+            sortedMetadataFileList.size()
+        );
+        List<String> metadataFilesToBeDeleted = metadataFilesEligibleToDelete.stream().filter(metadataFile -> {
+            try {
+                return !isLockAcquired(metadataFile);
+            } catch (IOException e) {
+                logger.error(
+                    "skipping metadata file ("
+                        + metadataFile
+                        + ") deletion for this run,"
+                        + " as checking lock for metadata is failing with error: "
+                        + e
+                );
+                return false;
+            }
+        }).collect(Collectors.toList());
+
+        sortedMetadataFileList.removeAll(metadataFilesToBeDeleted);
+        logger.debug(
+            "metadataFilesEligibleToDelete={} metadataFilesToBeDeleted={}",
+            metadataFilesEligibleToDelete,
+            metadataFilesEligibleToDelete
+        );
+
+        Map<String, UploadedSegmentMetadata> activeSegmentFilesMetadataMap = new HashMap<>();
+        Set<String> activeSegmentRemoteFilenames = new HashSet<>();
+        for (String metadataFile : sortedMetadataFileList) {
+            Map<String, UploadedSegmentMetadata> segmentMetadataMap = readMetadataFile(metadataFile).getMetadata();
+            activeSegmentFilesMetadataMap.putAll(segmentMetadataMap);
+            activeSegmentRemoteFilenames.addAll(
+                segmentMetadataMap.values().stream().map(metadata -> metadata.uploadedFilename).collect(Collectors.toSet())
+            );
+        }
+        for (String metadataFile : metadataFilesToBeDeleted) {
+            Map<String, UploadedSegmentMetadata> staleSegmentFilesMetadataMap = readMetadataFile(metadataFile).getMetadata();
+            Set<String> staleSegmentRemoteFilenames = staleSegmentFilesMetadataMap.values()
+                .stream()
+                .map(metadata -> metadata.uploadedFilename)
+                .collect(Collectors.toSet());
+            AtomicBoolean deletionSuccessful = new AtomicBoolean(true);
+            List<String> nonActiveDeletedSegmentFiles = new ArrayList<>();
+            staleSegmentRemoteFilenames.stream().filter(file -> !activeSegmentRemoteFilenames.contains(file)).forEach(file -> {
+                try {
+                    remoteDataDirectory.deleteFile(file);
+                    nonActiveDeletedSegmentFiles.add(file);
+                    if (!activeSegmentFilesMetadataMap.containsKey(getLocalSegmentFilename(file))) {
+                        segmentsUploadedToRemoteStore.remove(getLocalSegmentFilename(file));
+                    }
+                } catch (NoSuchFileException e) {
+                    logger.info("Segment file {} corresponding to metadata file {} does not exist in remote", file, metadataFile);
+                } catch (IOException e) {
+                    deletionSuccessful.set(false);
+                    logger.info(
+                        "Exception while deleting segment file {} corresponding to metadata file {}. Deletion will be re-tried",
+                        file,
+                        metadataFile
+                    );
+                }
+            });
+            logger.debug("nonActiveDeletedSegmentFiles={}", nonActiveDeletedSegmentFiles);
+            if (deletionSuccessful.get()) {
+                logger.debug("Deleting stale metadata file {} from remote segment store", metadataFile);
+                remoteMetadataDirectory.deleteFile(metadataFile);
+            }
+        }
+    }
+
+    public void deleteStaleSegmentsAsync(int lastNMetadataFilesToKeep) {
+        deleteStaleSegmentsAsync(lastNMetadataFilesToKeep, ActionListener.wrap(r -> {}, e -> {}));
+    }
+
+    /**
+     * Delete stale segment and metadata files asynchronously.
+     * This method calls {@link RemoteSegmentStoreDirectory#deleteStaleSegments(int)} in an async manner.
+     *
+     * @param lastNMetadataFilesToKeep number of metadata files to keep
+     */
+    public void deleteStaleSegmentsAsync(int lastNMetadataFilesToKeep, ActionListener<Void> listener) {
+        if (canDeleteStaleCommits.compareAndSet(true, false)) {
+            try {
+                threadPool.executor(ThreadPool.Names.REMOTE_PURGE).execute(() -> {
+                    try {
+                        deleteStaleSegments(lastNMetadataFilesToKeep);
+                        listener.onResponse(null);
+                    } catch (Exception e) {
+                        logger.error(
+                            "Exception while deleting stale commits from remote segment store, will retry delete post next commit",
+                            e
+                        );
+                        listener.onFailure(e);
+                    } finally {
+                        canDeleteStaleCommits.set(true);
+                    }
+                });
+            } catch (Exception e) {
+                logger.error("Exception occurred while scheduling deleteStaleCommits", e);
+                canDeleteStaleCommits.set(true);
+                listener.onFailure(e);
+            }
+        }
+    }
+
+    /*
+    Tries to delete shard level directory if it is empty
+    Return true if it deleted it successfully
+     */
+    private boolean deleteIfEmpty() throws IOException {
+        Collection<String> metadataFiles = remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+            MetadataFilenameUtils.METADATA_PREFIX,
+            1
+        );
+        if (metadataFiles.size() != 0) {
+            logger.info("Remote directory still has files, not deleting the path");
+            return false;
+        }
+
+        try {
+            remoteDataDirectory.delete();
+            remoteMetadataDirectory.delete();
+            mdLockManager.delete();
+        } catch (Exception e) {
+            logger.error("Exception occurred while deleting directory", e);
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void close() throws IOException {
+        deleteStaleSegmentsAsync(0, ActionListener.wrap(r -> deleteIfEmpty(), e -> logger.error("Failed to cleanup remote directory")));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactory.java b/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactory.java
new file mode 100644
index 0000000000000..cc55380894ecd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactory.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.Directory;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManager;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.plugins.IndexStorePlugin;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.function.Supplier;
+
+/**
+ * Factory for a remote store directory
+ *
+ * @opensearch.internal
+ */
+public class RemoteSegmentStoreDirectoryFactory implements IndexStorePlugin.DirectoryFactory {
+    private static final String SEGMENTS = "segments";
+
+    private final Supplier<RepositoriesService> repositoriesService;
+    private final RecoverySettings recoverySettings;
+
+    private final ThreadPool threadPool;
+
+    public RemoteSegmentStoreDirectoryFactory(
+        Supplier<RepositoriesService> repositoriesService,
+        ThreadPool threadPool,
+        RecoverySettings recoverySettings
+    ) {
+        this.repositoriesService = repositoriesService;
+        this.threadPool = threadPool;
+        this.recoverySettings = recoverySettings;
+    }
+
+    @Override
+    public Directory newDirectory(IndexSettings indexSettings, ShardPath path) throws IOException {
+        String repositoryName = indexSettings.getRemoteStoreRepository();
+        String indexUUID = indexSettings.getIndex().getUUID();
+        return newDirectory(repositoryName, indexUUID, path.getShardId());
+    }
+
+    public Directory newDirectory(String repositoryName, String indexUUID, ShardId shardId) throws IOException {
+        try (Repository repository = repositoriesService.get().repository(repositoryName)) {
+            assert repository instanceof BlobStoreRepository : "repository should be instance of BlobStoreRepository";
+            BlobStoreRepository blobStoreRepository = ((BlobStoreRepository) repository);
+            BlobPath commonBlobPath = blobStoreRepository.basePath();
+            commonBlobPath = commonBlobPath.add(indexUUID).add(String.valueOf(shardId.id())).add(SEGMENTS);
+
+            RemoteDirectory dataDirectory = new RemoteDirectory(
+                blobStoreRepository.blobStore().blobContainer(commonBlobPath.add("data")),
+                blobStoreRepository::maybeRateLimitRemoteUploadTransfers,
+                blobStoreRepository::maybeRateLimitRemoteDownloadTransfers
+            );
+            RemoteDirectory metadataDirectory = new RemoteDirectory(
+                blobStoreRepository.blobStore().blobContainer(commonBlobPath.add("metadata"))
+            );
+            RemoteStoreLockManager mdLockManager = RemoteStoreLockManagerFactory.newLockManager(
+                repositoriesService.get(),
+                repositoryName,
+                indexUUID,
+                String.valueOf(shardId.id())
+            );
+
+            return new RemoteSegmentStoreDirectory(dataDirectory, metadataDirectory, mdLockManager, threadPool, shardId, recoverySettings);
+        } catch (RepositoryMissingException e) {
+            throw new IllegalArgumentException("Repository should be created before creating index with remote_store enabled setting", e);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/Store.java b/server/src/main/java/org/opensearch/index/store/Store.java
index f4a94023a8ac8..285241ba89996 100644
--- a/server/src/main/java/org/opensearch/index/store/Store.java
+++ b/server/src/main/java/org/opensearch/index/store/Store.java
@@ -50,6 +50,7 @@
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.BufferedChecksum;
+import org.apache.lucene.store.BufferedChecksumIndexInput;
 import org.apache.lucene.store.ByteArrayDataInput;
 import org.apache.lucene.store.ChecksumIndexInput;
 import org.apache.lucene.store.Directory;
@@ -65,12 +66,8 @@
 import org.apache.lucene.util.Version;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.Streams;
+import org.opensearch.common.annotation.InternalApi;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
@@ -80,8 +77,13 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRefCounted;
 import org.opensearch.common.util.concurrent.RefCounted;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.iterable.Iterables;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
 import org.opensearch.env.ShardLockObtainFailedException;
@@ -91,7 +93,7 @@
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.AbstractIndexShardComponent;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.translog.Translog;
 
 import java.io.Closeable;
@@ -109,8 +111,8 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.Optional;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
@@ -120,6 +122,8 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
+import static org.opensearch.index.seqno.SequenceNumbers.LOCAL_CHECKPOINT_KEY;
+import static org.opensearch.index.store.Store.MetadataSnapshot.loadMetadata;
 
 /**
  * A Store provides plain access to files written by an opensearch index shard. Each shard
@@ -140,6 +144,8 @@
  *          store.decRef();
  *      }
  * </pre>
+ *
+ * @opensearch.internal
  */
 public class Store extends AbstractIndexShardComponent implements Closeable, RefCounted {
     /**
@@ -175,6 +181,10 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
     private final ReentrantReadWriteLock metadataLock = new ReentrantReadWriteLock();
     private final ShardLock shardLock;
     private final OnClose onClose;
+    private final ShardPath shardPath;
+
+    // used to ref count files when a new Reader is opened for PIT/Scroll queries
+    // prevents segment files deletion until the PIT/Scroll expires or is discarded
 
     private final AbstractRefCounted refCounter = new AbstractRefCounted("store") {
         @Override
@@ -185,10 +195,17 @@ protected void closeInternal() {
     };
 
     public Store(ShardId shardId, IndexSettings indexSettings, Directory directory, ShardLock shardLock) {
-        this(shardId, indexSettings, directory, shardLock, OnClose.EMPTY);
+        this(shardId, indexSettings, directory, shardLock, OnClose.EMPTY, null);
     }
 
-    public Store(ShardId shardId, IndexSettings indexSettings, Directory directory, ShardLock shardLock, OnClose onClose) {
+    public Store(
+        ShardId shardId,
+        IndexSettings indexSettings,
+        Directory directory,
+        ShardLock shardLock,
+        OnClose onClose,
+        ShardPath shardPath
+    ) {
         super(shardId, indexSettings);
         final TimeValue refreshInterval = indexSettings.getValue(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING);
         logger.debug("store stats are refreshed with refresh_interval [{}]", refreshInterval);
@@ -196,7 +213,7 @@ public Store(ShardId shardId, IndexSettings indexSettings, Directory directory,
         this.directory = new StoreDirectory(sizeCachingDir, Loggers.getLogger("index.store.deletes", shardId));
         this.shardLock = shardLock;
         this.onClose = onClose;
-
+        this.shardPath = shardPath;
         assert onClose != null;
         assert shardLock != null;
         assert shardLock.getShardId().equals(shardId);
@@ -207,6 +224,11 @@ public Directory directory() {
         return directory;
     }
 
+    @InternalApi
+    public ShardPath shardPath() {
+        return shardPath;
+    }
+
     /**
      * Returns the last committed segments info for this store
      *
@@ -215,7 +237,11 @@ public Directory directory() {
     public SegmentInfos readLastCommittedSegmentsInfo() throws IOException {
         failIfCorrupted();
         try {
-            return readSegmentsInfo(null, directory());
+            if (indexSettings.isRemoteSnapshot() && indexSettings.getExtendedCompatibilitySnapshotVersion() != null) {
+                return readSegmentInfosExtendedCompatibility(directory(), indexSettings.getExtendedCompatibilitySnapshotVersion());
+            } else {
+                return readSegmentsInfo(null, directory());
+            }
         } catch (CorruptIndexException | IndexFormatTooOldException | IndexFormatTooNewException ex) {
             markStoreCorrupted(ex);
             throw ex;
@@ -223,7 +249,9 @@ public SegmentInfos readLastCommittedSegmentsInfo() throws IOException {
     }
 
     /**
-     * Returns the segments info for the given commit or for the latest commit if the given commit is <code>null</code>
+     * Returns the segments info for the given commit or for the latest commit if the given commit is <code>null</code>.
+     * This method will throw an exception if the index is older than the standard backwards compatibility
+     * policy ( current major - 1). See also {@link #readSegmentInfosExtendedCompatibility(Directory, org.opensearch.Version)}.
      *
      * @throws IOException if the index is corrupted or the segments file is not present
      */
@@ -239,7 +267,27 @@ private static SegmentInfos readSegmentsInfo(IndexCommit commit, Directory direc
         } catch (Exception ex) {
             throw new CorruptIndexException("Hit unexpected exception while reading segment infos", "commit(" + commit + ")", ex);
         }
+    }
 
+    /**
+     * Returns the segments info for the latest commit in the given directory. Unlike
+     * {@link #readSegmentsInfo(IndexCommit, Directory)}, this method supports reading
+     * older Lucene indices on a best-effort basis.
+     *
+     * @throws IOException if the index is corrupted or the segments file is not present
+     */
+    private static SegmentInfos readSegmentInfosExtendedCompatibility(Directory directory, org.opensearch.Version minimumVersion)
+        throws IOException {
+        try {
+            return Lucene.readSegmentInfos(directory, minimumVersion);
+        } catch (EOFException eof) {
+            // TODO this should be caught by lucene - EOF is almost certainly an index corruption
+            throw new CorruptIndexException("Read past EOF while reading segment infos", "<latest-commit>", eof);
+        } catch (IOException exception) {
+            throw exception; // IOExceptions like too many open files are not necessarily a corruption - just bubble it up
+        } catch (Exception ex) {
+            throw new CorruptIndexException("Hit unexpected exception while reading segment infos", "<latest-commit>", ex);
+        }
     }
 
     final void ensureOpen() {
@@ -272,6 +320,13 @@ public MetadataSnapshot getMetadata(IndexCommit commit) throws IOException {
         return getMetadata(commit, false);
     }
 
+    /**
+     * Convenience wrapper around the {@link #getMetadata(IndexCommit)} method for null input.
+     */
+    public MetadataSnapshot getMetadata() throws IOException {
+        return getMetadata(null, false);
+    }
+
     /**
      * Returns a new MetadataSnapshot for the given commit. If the given commit is <code>null</code>
      * the latest commit point is used.
@@ -313,6 +368,62 @@ public MetadataSnapshot getMetadata(IndexCommit commit, boolean lockDirectory) t
         }
     }
 
+    /**
+     * Returns a new {@link MetadataSnapshot} for the given {@link SegmentInfos} object.
+     * In contrast to {@link #getMetadata(IndexCommit)}, this method is useful for scenarios
+     * where we need to construct a MetadataSnapshot from an in-memory SegmentInfos object that
+     * may not have a IndexCommit associated with it, such as with segment replication.
+     */
+    public MetadataSnapshot getMetadata(SegmentInfos segmentInfos) throws IOException {
+        return new MetadataSnapshot(segmentInfos, directory, logger);
+    }
+
+    /**
+     * Segment Replication method - Fetch a map of StoreFileMetadata for segments, ignoring Segment_N files.
+     * @param segmentInfos {@link SegmentInfos} from which to compute metadata.
+     * @return {@link Map} map file name to {@link StoreFileMetadata}.
+     */
+    public Map<String, StoreFileMetadata> getSegmentMetadataMap(SegmentInfos segmentInfos) throws IOException {
+        assert indexSettings.isSegRepEnabled();
+        return loadMetadata(segmentInfos, directory, logger, true).fileMetadata;
+    }
+
+    /**
+     * Segment Replication method
+     * Returns a diff between the Maps of StoreFileMetadata that can be used for getting list of files to copy over to a replica for segment replication. The returned diff will hold a list of files that are:
+     * <ul>
+     * <li>identical: they exist in both maps and they can be considered the same ie. they don't need to be recovered</li>
+     * <li>different: they exist in both maps but their they are not identical</li>
+     * <li>missing: files that exist in the source but not in the target</li>
+     * </ul>
+     */
+    public static RecoveryDiff segmentReplicationDiff(Map<String, StoreFileMetadata> source, Map<String, StoreFileMetadata> target) {
+        final List<StoreFileMetadata> identical = new ArrayList<>();
+        final List<StoreFileMetadata> different = new ArrayList<>();
+        final List<StoreFileMetadata> missing = new ArrayList<>();
+        for (StoreFileMetadata value : source.values()) {
+            if (value.name().startsWith(IndexFileNames.SEGMENTS)) {
+                continue;
+            }
+            if (target.containsKey(value.name()) == false) {
+                missing.add(value);
+            } else {
+                final StoreFileMetadata fileMetadata = target.get(value.name());
+                // match segments using checksum
+                if (fileMetadata.checksum().equals(value.checksum())) {
+                    identical.add(value);
+                } else {
+                    different.add(value);
+                }
+            }
+        }
+        return new RecoveryDiff(
+            Collections.unmodifiableList(identical),
+            Collections.unmodifiableList(different),
+            Collections.unmodifiableList(missing)
+        );
+    }
+
     /**
      * Renames all the given files from the key of the map to the
      * value of the map. All successfully renamed files are removed from the map in-place.
@@ -475,7 +586,7 @@ public static MetadataSnapshot readMetadataSnapshot(
             Directory dir = new NIOFSDirectory(indexLocation)
         ) {
             failIfCorrupted(dir);
-            return new MetadataSnapshot(null, dir, logger);
+            return new MetadataSnapshot((IndexCommit) null, dir, logger);
         } catch (IndexNotFoundException ex) {
             // that's fine - happens all the time no need to log
         } catch (FileNotFoundException | NoSuchFileException ex) {
@@ -680,13 +791,37 @@ public void cleanupAndVerify(String reason, MetadataSnapshot sourceMetadata) thr
                 }
             }
             directory.syncMetaData();
-            final Store.MetadataSnapshot metadataOrEmpty = getMetadata(null);
+            final Store.MetadataSnapshot metadataOrEmpty = getMetadata();
             verifyAfterCleanup(sourceMetadata, metadataOrEmpty);
         } finally {
             metadataLock.writeLock().unlock();
         }
     }
 
+    /**
+     * Segment replication method
+     *
+     * This method takes the segment info bytes to build SegmentInfos. It inc'refs files pointed by passed in SegmentInfos
+     * bytes to ensure they are not deleted.
+     *
+     * @param infosBytes bytes[] of SegmentInfos supposed to be sent over by primary excluding segment_N file
+     * @param segmentsGen segment generation number
+     * @throws IOException Exception while reading store and building segment infos
+     */
+    public SegmentInfos buildSegmentInfos(byte[] infosBytes, long segmentsGen) throws IOException {
+        try (final ChecksumIndexInput input = toIndexInput(infosBytes)) {
+            return SegmentInfos.readCommit(directory, input, segmentsGen);
+        }
+    }
+
+    /**
+     * This method formats byte[] containing the primary's SegmentInfos into lucene's {@link ChecksumIndexInput} that can be
+     * passed to SegmentInfos.readCommit
+     */
+    private ChecksumIndexInput toIndexInput(byte[] input) {
+        return new BufferedChecksumIndexInput(new ByteArrayIndexInput("Snapshot of SegmentInfos", input));
+    }
+
     // pkg private for testing
     final void verifyAfterCleanup(MetadataSnapshot sourceMetadata, MetadataSnapshot targetMetadata) {
         final RecoveryDiff recoveryDiff = targetMetadata.recoveryDiff(sourceMetadata);
@@ -734,13 +869,56 @@ public void beforeClose() {
         shardLock.setDetails("closing shard");
     }
 
-    static final class StoreDirectory extends FilterDirectory {
+    /**
+     * This method should only be used with Segment Replication.
+     * Perform a commit from a live {@link SegmentInfos}.  Replica engines with segrep do not have an IndexWriter and Lucene does not currently
+     * have the ability to create a writer directly from a SegmentInfos object.  To promote the replica as a primary and avoid reindexing, we must first commit
+     * on the replica so that it can be opened with a writeable engine. Further, InternalEngine currently invokes `trimUnsafeCommits` which reverts the engine to a previous safeCommit where the max seqNo is less than or equal
+     * to the current global checkpoint. It is likely that the replica has a maxSeqNo that is higher than the global cp and a new commit will be wiped.
+     *
+     * To get around these limitations, this method first creates an IndexCommit directly from SegmentInfos, it then
+     * uses an appending IW to create an IndexCommit from the commit created on SegmentInfos.
+     * This ensures that 1. All files in the new commit are fsynced and 2. Deletes older commit points so the only commit to start from is our new commit.
+     *
+     * @param latestSegmentInfos {@link SegmentInfos} The latest active infos
+     * @param maxSeqNo The engine's current maxSeqNo
+     * @param processedCheckpoint The engine's current processed checkpoint.
+     * @throws IOException when there is an IO error committing.
+     */
+    public void commitSegmentInfos(SegmentInfos latestSegmentInfos, long maxSeqNo, long processedCheckpoint) throws IOException {
+        assert indexSettings.isSegRepEnabled();
+        metadataLock.writeLock().lock();
+        try {
+            final Map<String, String> userData = new HashMap<>(latestSegmentInfos.getUserData());
+            userData.put(LOCAL_CHECKPOINT_KEY, String.valueOf(processedCheckpoint));
+            userData.put(SequenceNumbers.MAX_SEQ_NO, Long.toString(maxSeqNo));
+            latestSegmentInfos.setUserData(userData, false);
+            latestSegmentInfos.commit(directory());
+            directory.sync(latestSegmentInfos.files(true));
+            directory.syncMetaData();
+        } finally {
+            metadataLock.writeLock().unlock();
+        }
+    }
+
+    public DirectoryFileTransferTracker getDirectoryFileTransferTracker() {
+        return directory.getDirectoryFileTransferTracker();
+    }
 
+    /**
+     * A store directory
+     *
+     * @opensearch.internal
+     */
+    static final class StoreDirectory extends FilterDirectory {
         private final Logger deletesLogger;
 
+        public final DirectoryFileTransferTracker directoryFileTransferTracker;
+
         StoreDirectory(ByteSizeCachingDirectory delegateDirectory, Logger deletesLogger) {
             super(delegateDirectory);
             this.deletesLogger = deletesLogger;
+            this.directoryFileTransferTracker = new DirectoryFileTransferTracker();
         }
 
         /** Estimate the cumulative size of all files in this directory in bytes. */
@@ -778,6 +956,52 @@ public Set<String> getPendingDeletions() throws IOException {
             // to be removed once fixed in FilterDirectory.
             return unwrap(this).getPendingDeletions();
         }
+
+        public DirectoryFileTransferTracker getDirectoryFileTransferTracker() {
+            return directoryFileTransferTracker;
+        }
+
+        @Override
+        public void copyFrom(Directory from, String src, String dest, IOContext context) throws IOException {
+            long fileSize = from.fileLength(src);
+            beforeDownload(fileSize);
+            boolean success = false;
+            long startTime = System.currentTimeMillis();
+            try {
+                super.copyFrom(from, src, dest, context);
+                success = true;
+                afterDownload(fileSize, startTime);
+            } finally {
+                if (!success) {
+                    downloadFailed(fileSize, startTime);
+                }
+            }
+        }
+
+        /**
+         * Updates the amount of bytes attempted for download
+         */
+        private void beforeDownload(long fileSize) {
+            directoryFileTransferTracker.addTransferredBytesStarted(fileSize);
+        }
+
+        /**
+         * Updates
+         * - The amount of bytes that has been successfully downloaded from the source store
+         * - The last successful download completion timestamp
+         * - The last successfully downloaded file
+         * - Download speed (in bytes/sec)
+         */
+        private void afterDownload(long fileSize, long startTimeInMs) {
+            directoryFileTransferTracker.addTransferredBytesSucceeded(fileSize, startTimeInMs);
+        }
+
+        /**
+         * Updates the amount of bytes failed in download
+         */
+        private void downloadFailed(long fileSize, long startTimeInMs) {
+            directoryFileTransferTracker.addTransferredBytesFailed(fileSize, startTimeInMs);
+        }
     }
 
     /**
@@ -790,6 +1014,8 @@ public Set<String> getPendingDeletions() throws IOException {
      * change concurrently for safety reasons.
      *
      * @see StoreFileMetadata
+     *
+     * @opensearch.internal
      */
     public static final class MetadataSnapshot implements Iterable<StoreFileMetadata>, Writeable {
         private final Map<String, StoreFileMetadata> metadata;
@@ -813,7 +1039,14 @@ public MetadataSnapshot(Map<String, StoreFileMetadata> metadata, Map<String, Str
         }
 
         MetadataSnapshot(IndexCommit commit, Directory directory, Logger logger) throws IOException {
-            LoadedMetadata loadedMetadata = loadMetadata(commit, directory, logger);
+            this(loadMetadata(commit, directory, logger));
+        }
+
+        MetadataSnapshot(SegmentInfos segmentInfos, Directory directory, Logger logger) throws IOException {
+            this(loadMetadata(segmentInfos, directory, logger));
+        }
+
+        private MetadataSnapshot(LoadedMetadata loadedMetadata) {
             metadata = loadedMetadata.fileMetadata;
             commitUserData = loadedMetadata.userData;
             numDocs = loadedMetadata.numDocs;
@@ -863,6 +1096,11 @@ public long getNumDocs() {
             return numDocs;
         }
 
+        /**
+         * Metadata that is currently loaded
+         *
+         * @opensearch.internal
+         */
         static class LoadedMetadata {
             final Map<String, StoreFileMetadata> fileMetadata;
             final Map<String, String> userData;
@@ -876,40 +1114,9 @@ static class LoadedMetadata {
         }
 
         static LoadedMetadata loadMetadata(IndexCommit commit, Directory directory, Logger logger) throws IOException {
-            long numDocs;
-            Map<String, StoreFileMetadata> builder = new HashMap<>();
-            Map<String, String> commitUserDataBuilder = new HashMap<>();
             try {
                 final SegmentInfos segmentCommitInfos = Store.readSegmentsInfo(commit, directory);
-                numDocs = Lucene.getNumDocs(segmentCommitInfos);
-                commitUserDataBuilder.putAll(segmentCommitInfos.getUserData());
-                // we don't know which version was used to write so we take the max version.
-                Version maxVersion = segmentCommitInfos.getMinSegmentLuceneVersion();
-                for (SegmentCommitInfo info : segmentCommitInfos) {
-                    final Version version = info.info.getVersion();
-                    if (version == null) {
-                        // version is written since 3.1+: we should have already hit IndexFormatTooOld.
-                        throw new IllegalArgumentException("expected valid version value: " + info.info.toString());
-                    }
-                    if (version.onOrAfter(maxVersion)) {
-                        maxVersion = version;
-                    }
-                    for (String file : info.files()) {
-                        checksumFromLuceneFile(
-                            directory,
-                            file,
-                            builder,
-                            logger,
-                            version,
-                            SEGMENT_INFO_EXTENSION.equals(IndexFileNames.getExtension(file))
-                        );
-                    }
-                }
-                if (maxVersion == null) {
-                    maxVersion = org.opensearch.Version.CURRENT.minimumIndexCompatibilityVersion().luceneVersion;
-                }
-                final String segmentsFile = segmentCommitInfos.getSegmentsFileName();
-                checksumFromLuceneFile(directory, segmentsFile, builder, logger, maxVersion, true);
+                return loadMetadata(segmentCommitInfos, directory, logger);
             } catch (CorruptIndexException | IndexNotFoundException | IndexFormatTooOldException | IndexFormatTooNewException ex) {
                 // we either know the index is corrupted or it's just not there
                 throw ex;
@@ -935,6 +1142,52 @@ static LoadedMetadata loadMetadata(IndexCommit commit, Directory directory, Logg
                 }
                 throw ex;
             }
+        }
+
+        static LoadedMetadata loadMetadata(SegmentInfos segmentInfos, Directory directory, Logger logger) throws IOException {
+            return loadMetadata(segmentInfos, directory, logger, false);
+        }
+
+        static LoadedMetadata loadMetadata(SegmentInfos segmentInfos, Directory directory, Logger logger, boolean ignoreSegmentsFile)
+            throws IOException {
+            long numDocs = Lucene.getNumDocs(segmentInfos);
+            Map<String, String> commitUserDataBuilder = new HashMap<>();
+            commitUserDataBuilder.putAll(segmentInfos.getUserData());
+            Map<String, StoreFileMetadata> builder = new HashMap<>();
+            // we don't know which version was used to write so we take the max version.
+            Version maxVersion = segmentInfos.getMinSegmentLuceneVersion();
+            for (SegmentCommitInfo info : segmentInfos) {
+                final Version version = info.info.getVersion();
+                if (version == null) {
+                    // version is written since 3.1+: we should have already hit IndexFormatTooOld.
+                    throw new IllegalArgumentException("expected valid version value: " + info.info.toString());
+                }
+                // With segment replication enabled, we compute metadata snapshots from the latest in memory infos.
+                // In this case we will have SegmentInfos objects fetched from the primary's reader
+                // where the minSegmentLuceneVersion can be null even though there are segments.
+                // This is because the SegmentInfos object is not read from a commit/IndexInput, which sets
+                // minSegmentLuceneVersion.
+                if (maxVersion == null || version.onOrAfter(maxVersion)) {
+                    maxVersion = version;
+                }
+                for (String file : info.files()) {
+                    checksumFromLuceneFile(
+                        directory,
+                        file,
+                        builder,
+                        logger,
+                        version,
+                        SEGMENT_INFO_EXTENSION.equals(IndexFileNames.getExtension(file))
+                    );
+                }
+            }
+            if (maxVersion == null) {
+                maxVersion = org.opensearch.Version.CURRENT.minimumIndexCompatibilityVersion().luceneVersion;
+            }
+            if (ignoreSegmentsFile == false) {
+                final String segmentsFile = segmentInfos.getSegmentsFileName();
+                checksumFromLuceneFile(directory, segmentsFile, builder, logger, maxVersion, true);
+            }
             return new LoadedMetadata(unmodifiableMap(builder), unmodifiableMap(commitUserDataBuilder), numDocs);
         }
 
@@ -988,7 +1241,7 @@ public static void hashFile(BytesRefBuilder fileHash, InputStream in, long size)
             final int len = (int) Math.min(1024 * 1024, size); // for safety we limit this to 1MB
             fileHash.grow(len);
             fileHash.setLength(len);
-            final int readBytes = Streams.readFully(in, fileHash.bytes(), 0, len);
+            final int readBytes = in.readNBytes(fileHash.bytes(), 0, len);
             assert readBytes == len : Integer.toString(readBytes) + " != " + Integer.toString(len);
             assert fileHash.length() == len : Integer.toString(fileHash.length()) + " != " + Integer.toString(len);
         }
@@ -1010,6 +1263,29 @@ public Map<String, StoreFileMetadata> asMap() {
         private static final String LIV_FILE_EXTENSION = "liv"; // lucene 5 delete file
         private static final String SEGMENT_INFO_EXTENSION = "si";
 
+        /**
+         * Helper method used to group store files according to segment and commit.
+         *
+         * @see MetadataSnapshot#recoveryDiff(MetadataSnapshot)
+         */
+        private Iterable<List<StoreFileMetadata>> getGroupedFilesIterable() {
+            final Map<String, List<StoreFileMetadata>> perSegment = new HashMap<>();
+            final List<StoreFileMetadata> perCommitStoreFiles = new ArrayList<>();
+            for (StoreFileMetadata meta : this) {
+                final String segmentId = IndexFileNames.parseSegmentName(meta.name());
+                final String extension = IndexFileNames.getExtension(meta.name());
+                if (IndexFileNames.SEGMENTS.equals(segmentId)
+                    || DEL_FILE_EXTENSION.equals(extension)
+                    || LIV_FILE_EXTENSION.equals(extension)) {
+                    // only treat del files as per-commit files fnm files are generational but only for upgradable DV
+                    perCommitStoreFiles.add(meta);
+                } else {
+                    perSegment.computeIfAbsent(segmentId, k -> new ArrayList<>()).add(meta);
+                }
+            }
+            return Iterables.concat(perSegment.values(), Collections.singleton(perCommitStoreFiles));
+        }
+
         /**
          * Returns a diff between the two snapshots that can be used for recovery. The given snapshot is treated as the
          * recovery target and this snapshot as the source. The returned diff will hold a list of files that are:
@@ -1047,23 +1323,8 @@ public RecoveryDiff recoveryDiff(MetadataSnapshot recoveryTargetSnapshot) {
             final List<StoreFileMetadata> identical = new ArrayList<>();
             final List<StoreFileMetadata> different = new ArrayList<>();
             final List<StoreFileMetadata> missing = new ArrayList<>();
-            final Map<String, List<StoreFileMetadata>> perSegment = new HashMap<>();
-            final List<StoreFileMetadata> perCommitStoreFiles = new ArrayList<>();
-
-            for (StoreFileMetadata meta : this) {
-                final String segmentId = IndexFileNames.parseSegmentName(meta.name());
-                final String extension = IndexFileNames.getExtension(meta.name());
-                if (IndexFileNames.SEGMENTS.equals(segmentId)
-                    || DEL_FILE_EXTENSION.equals(extension)
-                    || LIV_FILE_EXTENSION.equals(extension)) {
-                    // only treat del files as per-commit files fnm files are generational but only for upgradable DV
-                    perCommitStoreFiles.add(meta);
-                } else {
-                    perSegment.computeIfAbsent(segmentId, k -> new ArrayList<>()).add(meta);
-                }
-            }
             final ArrayList<StoreFileMetadata> identicalFiles = new ArrayList<>();
-            for (List<StoreFileMetadata> segmentFiles : Iterables.concat(perSegment.values(), Collections.singleton(perCommitStoreFiles))) {
+            for (List<StoreFileMetadata> segmentFiles : getGroupedFilesIterable()) {
                 identicalFiles.clear();
                 boolean consistent = true;
                 for (StoreFileMetadata meta : segmentFiles) {
@@ -1160,6 +1421,8 @@ public String getSyncId() {
      * A class representing the diff between a recovery source and recovery target
      *
      * @see MetadataSnapshot#recoveryDiff(org.opensearch.index.store.Store.MetadataSnapshot)
+     *
+     * @opensearch.internal
      */
     public static final class RecoveryDiff {
         /**
@@ -1209,7 +1472,12 @@ public static String digestToString(long digest) {
         return Long.toString(digest, Character.MAX_RADIX);
     }
 
-    static class LuceneVerifyingIndexOutput extends VerifyingIndexOutput {
+    /**
+     * Class to verify the lucene index output
+     *
+     * @opensearch.internal
+     */
+    public static class LuceneVerifyingIndexOutput extends VerifyingIndexOutput {
 
         private final StoreFileMetadata metadata;
         private long writtenBytes;
@@ -1217,7 +1485,7 @@ static class LuceneVerifyingIndexOutput extends VerifyingIndexOutput {
         private String actualChecksum;
         private final byte[] footerChecksum = new byte[8]; // this holds the actual footer checksum data written by to this output
 
-        LuceneVerifyingIndexOutput(StoreFileMetadata metadata, IndexOutput out) {
+        public LuceneVerifyingIndexOutput(StoreFileMetadata metadata, IndexOutput out) {
             super(out);
             this.metadata = metadata;
             checksumPosition = metadata.length() - 8; // the last 8 bytes are the checksum - we store it in footerChecksum
@@ -1307,6 +1575,8 @@ public void writeBytes(byte[] b, int offset, int length) throws IOException {
      * This class supports random access (it is possible to seek backward and forward) in order to accommodate retry
      * mechanism that is used in some repository plugins (S3 for example). However, the checksum is only calculated on
      * the first read. All consecutive reads of the same data are not used to calculate the checksum.
+     *
+     * @opensearch.internal
      */
     static class VerifyingIndexInput extends ChecksumIndexInput {
         private final IndexInput input;
@@ -1479,6 +1749,8 @@ public void markStoreCorrupted(IOException exception) throws IOException {
 
     /**
      * A listener that is executed once the store is closed and all references to it are released
+     *
+     * @opensearch.internal
      */
     public interface OnClose extends Consumer<ShardLock> {
         OnClose EMPTY = new OnClose() {
@@ -1491,13 +1763,13 @@ public void accept(ShardLock Lock) {}
         };
     }
 
-    /**
-     * creates an empty lucene index and a corresponding empty translog. Any existing data will be deleted.
-     */
-    public void createEmpty(Version luceneVersion) throws IOException {
+    public void createEmpty(Version luceneVersion, String translogUUID) throws IOException {
         metadataLock.writeLock().lock();
         try (IndexWriter writer = newEmptyIndexWriter(directory, luceneVersion)) {
             final Map<String, String> map = new HashMap<>();
+            if (translogUUID != null) {
+                map.put(Translog.TRANSLOG_UUID_KEY, translogUUID);
+            }
             map.put(Engine.HISTORY_UUID_KEY, UUIDs.randomBase64UUID());
             map.put(SequenceNumbers.LOCAL_CHECKPOINT_KEY, Long.toString(SequenceNumbers.NO_OPS_PERFORMED));
             map.put(SequenceNumbers.MAX_SEQ_NO, Long.toString(SequenceNumbers.NO_OPS_PERFORMED));
@@ -1508,6 +1780,13 @@ public void createEmpty(Version luceneVersion) throws IOException {
         }
     }
 
+    /**
+     * creates an empty lucene index and a corresponding empty translog. Any existing data will be deleted.
+     */
+    public void createEmpty(Version luceneVersion) throws IOException {
+        createEmpty(luceneVersion, null);
+    }
+
     /**
      * Marks an existing lucene index with a new history uuid.
      * This is used to make sure no existing shard will recovery from this index using ops based recovery.
diff --git a/server/src/main/java/org/opensearch/index/store/StoreFileMetadata.java b/server/src/main/java/org/opensearch/index/store/StoreFileMetadata.java
index ea8704fe0f06f..f8c4df50afc8f 100644
--- a/server/src/main/java/org/opensearch/index/store/StoreFileMetadata.java
+++ b/server/src/main/java/org/opensearch/index/store/StoreFileMetadata.java
@@ -35,15 +35,20 @@
 import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.text.ParseException;
 import java.util.Objects;
 
+/**
+ * Metadata for the store file
+ *
+ * @opensearch.internal
+ */
 public class StoreFileMetadata implements Writeable {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/index/store/StoreStats.java b/server/src/main/java/org/opensearch/index/store/StoreStats.java
index 7122fa853676b..f6c99c8c3aa78 100644
--- a/server/src/main/java/org/opensearch/index/store/StoreStats.java
+++ b/server/src/main/java/org/opensearch/index/store/StoreStats.java
@@ -34,15 +34,20 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Statistics about an OpenSearch Store
+ *
+ * @opensearch.internal
+ */
 public class StoreStats implements Writeable, ToXContentFragment {
 
     /**
@@ -133,6 +138,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for store statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String STORE = "store";
         static final String SIZE = "size";
diff --git a/server/src/main/java/org/opensearch/index/store/VerifyingIndexOutput.java b/server/src/main/java/org/opensearch/index/store/VerifyingIndexOutput.java
index 7c005d5abd175..507f7149319fe 100644
--- a/server/src/main/java/org/opensearch/index/store/VerifyingIndexOutput.java
+++ b/server/src/main/java/org/opensearch/index/store/VerifyingIndexOutput.java
@@ -40,6 +40,8 @@
 /**
  * abstract class for verifying what was written.
  * subclasses override {@link #writeByte(byte)} and {@link #writeBytes(byte[], int, int)}
+ *
+ * @opensearch.internal
  */
 // do NOT optimize this class for performance
 public abstract class VerifyingIndexOutput extends FilterIndexOutput {
diff --git a/server/src/main/java/org/opensearch/index/store/exception/ChecksumCombinationException.java b/server/src/main/java/org/opensearch/index/store/exception/ChecksumCombinationException.java
new file mode 100644
index 0000000000000..d8e1739fbaa9d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/exception/ChecksumCombinationException.java
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.exception;
+
+import org.apache.lucene.index.CorruptIndexException;
+
+/**
+ * Exception is raised when combination of two CRC checksums fail.
+ *
+ * @opensearch.internal
+ */
+public class ChecksumCombinationException extends CorruptIndexException {
+    public ChecksumCombinationException(String msg, String resourceDescription) {
+        super(msg, resourceDescription);
+    }
+
+    public ChecksumCombinationException(String msg, String resourceDescription, Throwable cause) {
+        super(msg, resourceDescription, cause);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/exception/package-info.java b/server/src/main/java/org/opensearch/index/store/exception/package-info.java
new file mode 100644
index 0000000000000..b93ce9ffd6201
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/exception/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Contains exceptions thrown during segment file uploads */
+package org.opensearch.index.store.exception;
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/FileLockInfo.java b/server/src/main/java/org/opensearch/index/store/lockmanager/FileLockInfo.java
new file mode 100644
index 0000000000000..24f42743e1a04
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/FileLockInfo.java
@@ -0,0 +1,138 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import java.nio.file.NoSuchFileException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * A Class that defines Info about Remote Store File Lock.
+ * This is used to provide Remote Store Lock Information and some utility methods for the Lock file.
+ * @opensearch.internal
+ */
+public class FileLockInfo implements LockInfo {
+    private String fileToLock;
+    private String acquirerId;
+
+    public String getAcquirerId() {
+        return acquirerId;
+    }
+
+    public String getFileToLock() {
+        return fileToLock;
+    }
+
+    private void setFileToLock(String fileName) {
+        this.fileToLock = fileName;
+    }
+
+    private void setAcquirerId(String acquirerId) {
+        this.acquirerId = acquirerId;
+    }
+
+    @Override
+    public String generateLockName() {
+        validateRequiredParameters(this);
+        return LockFileUtils.generateLockName(fileToLock, acquirerId);
+    }
+
+    String getLockPrefix() {
+        if (fileToLock == null || fileToLock.isBlank()) {
+            throw new IllegalArgumentException("File to Lock should be provided");
+        }
+        return fileToLock + RemoteStoreLockManagerUtils.SEPARATOR;
+    }
+
+    String getLockForAcquirer(String[] lockFiles) throws NoSuchFileException {
+        if (acquirerId == null || acquirerId.isBlank()) {
+            throw new IllegalArgumentException("Acquirer ID should be provided");
+        }
+        List<String> locksForAcquirer = Arrays.stream(lockFiles)
+            .filter(lockFile -> acquirerId.equals(LockFileUtils.getAcquirerIdFromLock(lockFile)))
+            .collect(Collectors.toList());
+
+        if (locksForAcquirer.isEmpty()) {
+            throw new NoSuchFileException("No lock file found for the acquirer: " + acquirerId);
+        }
+        if (locksForAcquirer.size() != 1) {
+            throw new IllegalStateException("Expected single lock file but found [" + locksForAcquirer.size() + "] lock files");
+        }
+        return locksForAcquirer.get(0);
+    }
+
+    public static LockInfoBuilder getLockInfoBuilder() {
+        return new LockInfoBuilder();
+    }
+
+    private static void validateRequiredParameters(FileLockInfo fileLockInfo) {
+        if (fileLockInfo.getAcquirerId() == null || fileLockInfo.getAcquirerId().isBlank()) {
+            throw new IllegalArgumentException("Acquirer ID should be provided");
+        }
+        if (fileLockInfo.getFileToLock() == null || fileLockInfo.getFileToLock().isBlank()) {
+            throw new IllegalArgumentException("File to Lock should be provided");
+        }
+    }
+
+    static class LockFileUtils {
+        static String generateLockName(String fileToLock, String acquirerId) {
+            return String.join(RemoteStoreLockManagerUtils.SEPARATOR, fileToLock, acquirerId)
+                + RemoteStoreLockManagerUtils.LOCK_FILE_EXTENSION;
+        }
+
+        public static String getFileToLockNameFromLock(String lockName) {
+            String[] lockNameTokens = lockName.split(RemoteStoreLockManagerUtils.SEPARATOR);
+
+            if (lockNameTokens.length != 2) {
+                throw new IllegalArgumentException("Provided Lock Name " + lockName + " is not Valid.");
+            }
+            return lockNameTokens[0];
+        }
+
+        public static String getAcquirerIdFromLock(String lockName) {
+            String[] lockNameTokens = lockName.split(RemoteStoreLockManagerUtils.SEPARATOR);
+
+            if (lockNameTokens.length != 2) {
+                throw new IllegalArgumentException("Provided Lock Name " + lockName + " is not Valid.");
+            }
+            return lockNameTokens[1].replace(RemoteStoreLockManagerUtils.LOCK_FILE_EXTENSION, "");
+        }
+    }
+
+    /**
+     * A Builder Class to build an Instance of {@code FileLockInfo}
+     * @opensearch.internal
+     */
+    public static class LockInfoBuilder implements LockInfo.LockInfoBuilder {
+        private final FileLockInfo lockFileInfo;
+
+        LockInfoBuilder() {
+            this.lockFileInfo = new FileLockInfo();
+        }
+
+        public LockInfoBuilder withFileToLock(String fileToLock) {
+            lockFileInfo.setFileToLock(fileToLock);
+            return this;
+        }
+
+        public LockInfoBuilder withAcquirerId(String acquirerId) {
+            lockFileInfo.setAcquirerId(acquirerId);
+            return this;
+        }
+
+        @Override
+        public FileLockInfo build() {
+            if (lockFileInfo.fileToLock == null && lockFileInfo.acquirerId == null) {
+                throw new IllegalStateException("Either File to Lock or AcquirerId should be provided to instantiate FileLockInfo");
+            }
+            return lockFileInfo;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/LockInfo.java b/server/src/main/java/org/opensearch/index/store/lockmanager/LockInfo.java
new file mode 100644
index 0000000000000..1470969540d36
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/LockInfo.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+/**
+ * An Interface that defines Remote Store Lock Information.
+ * Individual Implemented Classes of this interface can decide how the lock should look like and its contents.
+ * @opensearch.internal
+ */
+public interface LockInfo {
+    /**
+     * A function which generates the lock name on the basis of given information.
+     * @return the name of the lock.
+     */
+    String generateLockName();
+
+    /**
+     * An Interface that defines a Lock Info Builder.
+     */
+    public static interface LockInfoBuilder {
+        /**
+         * Method to build Lock Info Instance.
+         */
+        public LockInfo build();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreCommitLevelLockManager.java b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreCommitLevelLockManager.java
new file mode 100644
index 0000000000000..20b6ded9f2401
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreCommitLevelLockManager.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import java.io.IOException;
+
+/**
+ * An Interface that defines Commit Level Lock in Remote Store. We can lock the segment files corresponding to a given
+ * primaryTerm and Commit Generation.
+ *
+ * @opensearch.internal
+ */
+public interface RemoteStoreCommitLevelLockManager {
+    /**
+     *
+     * This method will be used to acquire lock on segment files of a specific commit.
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation Commit Generation
+     * @param acquirerId Resource ID which wants to acquire lock on the commit.
+     * @throws IOException in case there is a problem in acquiring lock on a commit.
+     */
+    void acquireLock(long primaryTerm, long generation, String acquirerId) throws IOException;
+
+    /**
+     * This method will be used to release lock on segment files of a specific commit, which got acquired by given
+     * resource.
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation Commit Generation
+     * @param acquirerId Resource ID for which lock needs to be released.
+     * @throws IOException in case there is a problem in releasing lock on a commit.
+     */
+    void releaseLock(long primaryTerm, long generation, String acquirerId) throws IOException;
+
+    /**
+     * This method will be used to check if a specific commit have any lock acquired on it or not.
+     * @param primaryTerm Primary Term of index at the time of commit.
+     * @param generation Commit Generation
+     * @return true if given commit is locked, else false.
+     * @throws IOException in case there is a problem in checking if a commit is locked or not.
+     */
+    Boolean isLockAcquired(long primaryTerm, long generation) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManager.java b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManager.java
new file mode 100644
index 0000000000000..9eb066d9e955e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManager.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import java.io.IOException;
+
+/**
+ * An Interface that defines Remote Store Lock Manager.
+ * This will provide the functionality to acquire lock, release lock or to check if a lock is acquired on a specific
+ * file in remote store.
+ * @opensearch.internal
+ */
+public interface RemoteStoreLockManager {
+    /**
+     *
+     * @param lockInfo lock info instance for which we need to acquire lock.
+     * @throws IOException throws exception in case there is a problem with acquiring lock.
+     */
+    void acquire(LockInfo lockInfo) throws IOException;
+
+    /**
+     *
+     * @param lockInfo lock info instance for which lock need to be removed.
+     * @throws IOException throws exception in case there is a problem in releasing lock.
+     */
+    void release(LockInfo lockInfo) throws IOException;
+
+    /**
+     *
+     * @param lockInfo lock info instance for which we need to check if lock is acquired.
+     * @return whether a lock is acquired on the given lock info.
+     * @throws IOException throws exception in case there is a problem in checking if a given file is locked or not.
+     */
+    Boolean isAcquired(LockInfo lockInfo) throws IOException;
+
+    /**
+     * Acquires lock on the file mentioned in originalLockInfo for acquirer mentioned in clonedLockInfo.
+     * There can occur a race condition where the original file is deleted before we can use it to acquire lock for the new acquirer. Until we have a
+     * fix on LockManager side, Implementors must ensure thread safety for this operation.
+     * @param originalLockInfo lock info instance for original lock.
+     * @param clonedLockInfo lock info instance for which lock needs to be cloned.
+     * @throws IOException throws IOException if originalResource itself do not have any lock.
+     */
+    void cloneLock(LockInfo originalLockInfo, LockInfo clonedLockInfo) throws IOException;
+
+    /*
+    Deletes all lock related files and directories
+     */
+    void delete() throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactory.java b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactory.java
new file mode 100644
index 0000000000000..1a306f3261094
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactory.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+
+import java.io.IOException;
+import java.util.function.Supplier;
+
+/**
+ * Factory for remote store lock manager
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreLockManagerFactory {
+    private static final String SEGMENTS = "segments";
+    private static final String LOCK_FILES = "lock_files";
+    private final Supplier<RepositoriesService> repositoriesService;
+
+    public RemoteStoreLockManagerFactory(Supplier<RepositoriesService> repositoriesService) {
+        this.repositoriesService = repositoriesService;
+    }
+
+    public RemoteStoreLockManager newLockManager(String repositoryName, String indexUUID, String shardId) throws IOException {
+        return newLockManager(repositoriesService.get(), repositoryName, indexUUID, shardId);
+    }
+
+    public static RemoteStoreMetadataLockManager newLockManager(
+        RepositoriesService repositoriesService,
+        String repositoryName,
+        String indexUUID,
+        String shardId
+    ) throws IOException {
+        try (Repository repository = repositoriesService.repository(repositoryName)) {
+            assert repository instanceof BlobStoreRepository : "repository should be instance of BlobStoreRepository";
+            BlobPath shardLevelBlobPath = ((BlobStoreRepository) repository).basePath().add(indexUUID).add(shardId).add(SEGMENTS);
+            RemoteBufferedOutputDirectory shardMDLockDirectory = createRemoteBufferedOutputDirectory(
+                repository,
+                shardLevelBlobPath,
+                LOCK_FILES
+            );
+
+            return new RemoteStoreMetadataLockManager(shardMDLockDirectory);
+        } catch (RepositoryMissingException e) {
+            throw new IllegalArgumentException("Repository should be present to acquire/release lock", e);
+        }
+    }
+
+    // TODO: remove this once we add poller in place to trigger remote store cleanup
+    // see: https://github.com/opensearch-project/OpenSearch/issues/8469
+    public Supplier<RepositoriesService> getRepositoriesService() {
+        return repositoriesService;
+    }
+
+    private static RemoteBufferedOutputDirectory createRemoteBufferedOutputDirectory(
+        Repository repository,
+        BlobPath commonBlobPath,
+        String extention
+    ) {
+        BlobPath extendedPath = commonBlobPath.add(extention);
+        BlobContainer dataBlobContainer = ((BlobStoreRepository) repository).blobStore().blobContainer(extendedPath);
+        return new RemoteBufferedOutputDirectory(dataBlobContainer);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerUtils.java b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerUtils.java
new file mode 100644
index 0000000000000..452dfc329d88b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerUtils.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+/**
+ * Utility class for remote store lock manager,
+ * right now only have constants defined, we can add methods as well here in the future.
+ * @opensearch.internal
+ */
+public class RemoteStoreLockManagerUtils {
+    static final String FILE_TO_LOCK_NAME = "file_to_lock";
+    static final String SEPARATOR = "___";
+    static final String LOCK_FILE_EXTENSION = ".lock";
+    static final String ACQUIRER_ID = "acquirer_id";
+    public static final String NO_TTL = "-1";
+    static final String LOCK_EXPIRY_TIME = "lock_expiry_time";
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManager.java b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManager.java
new file mode 100644
index 0000000000000..fd7906729e314
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManager.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+
+import java.io.IOException;
+import java.nio.file.NoSuchFileException;
+import java.util.Collection;
+import java.util.Objects;
+
+/**
+ * A Class that implements Remote Store Lock Manager by creating lock files for the remote store files that needs to
+ * be locked.
+ * It uses {@code LockFileInfo} instance to get the information about the lock file on which operations need to
+ * be executed.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreMetadataLockManager implements RemoteStoreLockManager {
+    private static final Logger logger = LogManager.getLogger(RemoteStoreMetadataLockManager.class);
+    private final RemoteBufferedOutputDirectory lockDirectory;
+
+    public RemoteStoreMetadataLockManager(RemoteBufferedOutputDirectory lockDirectory) {
+        this.lockDirectory = lockDirectory;
+    }
+
+    /**
+     * Acquires lock on the file mentioned in LockInfo Instance.
+     * @param lockInfo File Lock Info instance for which we need to acquire lock.
+     * @throws IOException in case there is some failure while acquiring lock.
+     */
+    @Override
+    public void acquire(LockInfo lockInfo) throws IOException {
+        assert lockInfo instanceof FileLockInfo : "lockInfo should be instance of FileLockInfo";
+        IndexOutput indexOutput = lockDirectory.createOutput(lockInfo.generateLockName(), IOContext.DEFAULT);
+        indexOutput.close();
+    }
+
+    /**
+     * Releases Locks acquired by a given acquirer which is passed in LockInfo Instance.
+     * If the lock file doesn't exist for the acquirer, release will be a no-op.
+     * Right now this method is only used to release locks for a given acquirer,
+     * This can be extended in future to handle other cases as well, like:
+     * - release lock for given fileToLock and AcquirerId
+     * - release all locks for given fileToLock
+     * @param lockInfo File Lock Info instance for which lock need to be removed.
+     * @throws IOException in case there is some failure in releasing locks.
+     */
+    @Override
+    public void release(LockInfo lockInfo) throws IOException {
+        assert lockInfo instanceof FileLockInfo : "lockInfo should be instance of FileLockInfo";
+        String[] lockFiles = lockDirectory.listAll();
+        try {
+            String lockToRelease = ((FileLockInfo) lockInfo).getLockForAcquirer(lockFiles);
+            lockDirectory.deleteFile(lockToRelease);
+        } catch (NoSuchFileException e) {
+            // Ignoring if the file to be deleted is not present.
+            logger.info("No lock file found for acquirerId: {}", ((FileLockInfo) lockInfo).getAcquirerId());
+        }
+    }
+
+    /**
+     * Checks whether a given file have any lock on it or not.
+     * @param lockInfo File Lock Info instance for which we need to check if lock is acquired.
+     * @return true if lock is acquired on a file, else false.
+     * @throws IOException in case there is some failure in checking locks for a file.
+     */
+    @Override
+    public Boolean isAcquired(LockInfo lockInfo) throws IOException {
+        assert lockInfo instanceof FileLockInfo : "lockInfo should be instance of FileLockInfo";
+        Collection<String> lockFiles = lockDirectory.listFilesByPrefix(((FileLockInfo) lockInfo).getLockPrefix());
+        return !lockFiles.isEmpty();
+    }
+
+    /**
+     * Acquires lock on the file mentioned in originalLockInfo for acquirer mentioned in clonedLockInfo.
+     * Snapshot layer enforces thread safety by having checks in place to ensure that the source snapshot is not being deleted before proceeding
+     * with the clone operation. Hence, the original lock file would always be present while acquiring the lock for cloned snapshot.
+     * @param originalLockInfo lock info instance for original lock.
+     * @param clonedLockInfo lock info instance for which lock needs to be cloned.
+     * @throws IOException throws IOException if originalResource itself do not have any lock.
+     */
+    @Override
+    public void cloneLock(LockInfo originalLockInfo, LockInfo clonedLockInfo) throws IOException {
+        assert originalLockInfo instanceof FileLockInfo : "originalLockInfo should be instance of FileLockInfo";
+        assert clonedLockInfo instanceof FileLockInfo : "clonedLockInfo should be instance of FileLockInfo";
+        String originalResourceId = Objects.requireNonNull(((FileLockInfo) originalLockInfo).getAcquirerId());
+        String clonedResourceId = Objects.requireNonNull(((FileLockInfo) clonedLockInfo).getAcquirerId());
+        assert originalResourceId != null && clonedResourceId != null : "provided resourceIds should not be null";
+        String[] lockFiles = lockDirectory.listAll();
+        String lockNameForAcquirer = ((FileLockInfo) originalLockInfo).getLockForAcquirer(lockFiles);
+        String fileToLockName = FileLockInfo.LockFileUtils.getFileToLockNameFromLock(lockNameForAcquirer);
+        acquire(FileLockInfo.getLockInfoBuilder().withFileToLock(fileToLockName).withAcquirerId(clonedResourceId).build());
+    }
+
+    public void delete() throws IOException {
+        lockDirectory.delete();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/lockmanager/package-info.java b/server/src/main/java/org/opensearch/index/store/lockmanager/package-info.java
new file mode 100644
index 0000000000000..d68edd02696be
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/lockmanager/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing classes for remote segment store md lock manager
+ */
+package org.opensearch.index.store.lockmanager;
diff --git a/server/src/main/java/org/opensearch/index/store/package-info.java b/server/src/main/java/org/opensearch/index/store/package-info.java
new file mode 100644
index 0000000000000..cec95f35dba06
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/package-info.java
@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing classes to access files written by an index shard.
+ * see {@link org.opensearch.index.store.Store} for details
+ */
+package org.opensearch.index.store;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectory.java b/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectory.java
new file mode 100644
index 0000000000000..f0f2edd9ae6b8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectory.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.directory;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FSDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.Lock;
+import org.apache.lucene.store.NoLockFactory;
+import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
+import org.opensearch.index.store.remote.file.OnDemandBlockSnapshotIndexInput;
+import org.opensearch.index.store.remote.utils.TransferManager;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * a Directory implementation that can read directly from index snapshot stored remotely in a blob store repository.
+ * This implementation is following this design https://github.com/opensearch-project/OpenSearch/issues/4033
+ *
+ * @opensearch.internal
+ */
+public final class RemoteSnapshotDirectory extends Directory {
+
+    public static final Version SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION = LegacyESVersion.fromId(6000099);
+
+    private static final String VIRTUAL_FILE_PREFIX = BlobStoreRepository.VIRTUAL_DATA_BLOB_PREFIX;
+
+    private final Map<String, BlobStoreIndexShardSnapshot.FileInfo> fileInfoMap;
+    private final FSDirectory localStoreDir;
+    private final TransferManager transferManager;
+
+    public RemoteSnapshotDirectory(BlobStoreIndexShardSnapshot snapshot, FSDirectory localStoreDir, TransferManager transferManager) {
+        this.fileInfoMap = snapshot.indexFiles()
+            .stream()
+            .collect(Collectors.toMap(BlobStoreIndexShardSnapshot.FileInfo::physicalName, f -> f));
+        this.localStoreDir = localStoreDir;
+        this.transferManager = transferManager;
+    }
+
+    @Override
+    public String[] listAll() throws IOException {
+        return fileInfoMap.keySet().toArray(new String[0]);
+    }
+
+    @Override
+    public void deleteFile(String name) throws IOException {}
+
+    @Override
+    public IndexOutput createOutput(String name, IOContext context) {
+        return NoopIndexOutput.INSTANCE;
+    }
+
+    @Override
+    public IndexInput openInput(String name, IOContext context) throws IOException {
+        final BlobStoreIndexShardSnapshot.FileInfo fileInfo = fileInfoMap.get(name);
+
+        if (fileInfo.name().startsWith(VIRTUAL_FILE_PREFIX)) {
+            return new ByteArrayIndexInput(fileInfo.physicalName(), fileInfo.metadata().hash().bytes);
+        }
+        return new OnDemandBlockSnapshotIndexInput(fileInfo, localStoreDir, transferManager);
+    }
+
+    @Override
+    public void close() throws IOException {
+        localStoreDir.close();
+    }
+
+    @Override
+    public long fileLength(String name) throws IOException {
+        return fileInfoMap.get(name).length();
+    }
+
+    @Override
+    public Set<String> getPendingDeletions() throws IOException {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public IndexOutput createTempOutput(String prefix, String suffix, IOContext context) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void sync(Collection<String> names) throws IOException {}
+
+    @Override
+    public void syncMetaData() {}
+
+    @Override
+    public void rename(String source, String dest) throws IOException {}
+
+    @Override
+    public Lock obtainLock(String name) throws IOException {
+        return NoLockFactory.INSTANCE.obtainLock(null, null);
+    }
+
+    static class NoopIndexOutput extends IndexOutput {
+
+        final static NoopIndexOutput INSTANCE = new NoopIndexOutput();
+
+        NoopIndexOutput() {
+            super("noop", "noop");
+        }
+
+        @Override
+        public void close() throws IOException {
+
+        }
+
+        @Override
+        public long getFilePointer() {
+            return 0;
+        }
+
+        @Override
+        public long getChecksum() throws IOException {
+            return 0;
+        }
+
+        @Override
+        public void writeByte(byte b) throws IOException {
+
+        }
+
+        @Override
+        public void writeBytes(byte[] b, int offset, int length) throws IOException {
+
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectoryFactory.java b/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectoryFactory.java
new file mode 100644
index 0000000000000..7cfa738e75e52
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/directory/RemoteSnapshotDirectoryFactory.java
@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.directory;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FSDirectory;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
+import org.opensearch.index.snapshots.blobstore.IndexShardSnapshot;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.utils.TransferManager;
+import org.opensearch.plugins.IndexStorePlugin;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.snapshots.SnapshotId;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.function.Supplier;
+
+/**
+ * Factory for a Directory implementation that can read directly from index
+ * data stored remotely in a blob store repository.
+ *
+ * @opensearch.internal
+ */
+public final class RemoteSnapshotDirectoryFactory implements IndexStorePlugin.DirectoryFactory {
+    public static final String LOCAL_STORE_LOCATION = "RemoteLocalStore";
+
+    private final Supplier<RepositoriesService> repositoriesService;
+    private final ThreadPool threadPool;
+
+    private final FileCache remoteStoreFileCache;
+
+    public RemoteSnapshotDirectoryFactory(
+        Supplier<RepositoriesService> repositoriesService,
+        ThreadPool threadPool,
+        FileCache remoteStoreFileCache
+    ) {
+        this.repositoriesService = repositoriesService;
+        this.threadPool = threadPool;
+        this.remoteStoreFileCache = remoteStoreFileCache;
+    }
+
+    @Override
+    public Directory newDirectory(IndexSettings indexSettings, ShardPath localShardPath) throws IOException {
+        final String repositoryName = IndexSettings.SEARCHABLE_SNAPSHOT_REPOSITORY.get(indexSettings.getSettings());
+        final Repository repository = repositoriesService.get().repository(repositoryName);
+        assert repository instanceof BlobStoreRepository : "repository should be instance of BlobStoreRepository";
+        final BlobStoreRepository blobStoreRepository = (BlobStoreRepository) repository;
+        try {
+            return createRemoteSnapshotDirectoryFromSnapshot(indexSettings, localShardPath, blobStoreRepository).get();
+        } catch (InterruptedException | ExecutionException e) {
+            throw new IllegalStateException(e);
+        }
+    }
+
+    private Future<RemoteSnapshotDirectory> createRemoteSnapshotDirectoryFromSnapshot(
+        IndexSettings indexSettings,
+        ShardPath localShardPath,
+        BlobStoreRepository blobStoreRepository
+    ) throws IOException {
+        final BlobPath blobPath = blobStoreRepository.basePath()
+            .add("indices")
+            .add(IndexSettings.SEARCHABLE_SNAPSHOT_INDEX_ID.get(indexSettings.getSettings()))
+            .add(Integer.toString(localShardPath.getShardId().getId()));
+        final SnapshotId snapshotId = new SnapshotId(
+            IndexSettings.SEARCHABLE_SNAPSHOT_ID_NAME.get(indexSettings.getSettings()),
+            IndexSettings.SEARCHABLE_SNAPSHOT_ID_UUID.get(indexSettings.getSettings())
+        );
+        Path localStorePath = localShardPath.getDataPath().resolve(LOCAL_STORE_LOCATION);
+        FSDirectory localStoreDir = FSDirectory.open(Files.createDirectories(localStorePath));
+        // make sure directory is flushed to persistent storage
+        localStoreDir.syncMetaData();
+        // this trick is needed to bypass assertions in BlobStoreRepository::assertAllowableThreadPools in case of node restart and a remote
+        // index restore is invoked
+        return threadPool.executor(ThreadPool.Names.SNAPSHOT).submit(() -> {
+            final BlobContainer blobContainer = blobStoreRepository.blobStore().blobContainer(blobPath);
+            final IndexShardSnapshot indexShardSnapshot = blobStoreRepository.loadShardSnapshot(blobContainer, snapshotId);
+            assert indexShardSnapshot instanceof BlobStoreIndexShardSnapshot
+                : "indexShardSnapshot should be an instance of BlobStoreIndexShardSnapshot";
+            final BlobStoreIndexShardSnapshot snapshot = (BlobStoreIndexShardSnapshot) indexShardSnapshot;
+            TransferManager transferManager = new TransferManager(blobContainer, remoteStoreFileCache);
+            return new RemoteSnapshotDirectory(snapshot, localStoreDir, transferManager);
+        });
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/directory/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/directory/package-info.java
new file mode 100644
index 0000000000000..02c53943ecef8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/directory/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing classes to create remoted snapshot directories
+ */
+package org.opensearch.index.store.remote.directory;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInput.java b/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInput.java
new file mode 100644
index 0000000000000..7319a5324777a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInput.java
@@ -0,0 +1,466 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.file;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.RandomAccessInput;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+
+import java.io.Closeable;
+import java.io.EOFException;
+import java.io.IOException;
+import java.lang.ref.Cleaner;
+import java.util.Objects;
+
+/**
+ * Class acts as a virtual file mechanism for the accessed files and only fetches the required blocks of the actual file.
+ * Original/Main IndexInput file will be split using {@link OnDemandBlockIndexInput.Builder#DEFAULT_BLOCK_SIZE_SHIFT}. This class has all the
+ * logic of how and when to fetch specific block of the main file. Each block is identified by {@link OnDemandBlockIndexInput#currentBlockId}.
+ * <br>
+ * This class delegate the responsibility of actually fetching the block when demanded to its subclasses using
+ * {@link OnDemandBlockIndexInput#fetchBlock(int)}.
+ *
+ * Like {@link IndexInput}, this class may only be used from one thread as it is not thread safe.
+ * However, a cleaning action may run from another thread triggered by the {@link Cleaner}, but
+ * this is okay because at that point the {@link OnDemandBlockIndexInput} instance is phantom
+ * reachable and therefore not able to be accessed by any other thread.
+ *
+ * @opensearch.internal
+ */
+abstract class OnDemandBlockIndexInput extends IndexInput implements RandomAccessInput {
+    private static final Logger logger = LogManager.getLogger(OnDemandBlockIndexInput.class);
+
+    public static final String CLEANER_THREAD_NAME_PREFIX = "index-input-cleaner";
+
+    /**
+     * A single static Cleaner instance to ensure any unclosed clone of an
+     * IndexInput is closed. This instance creates a single daemon thread on
+     * which it performs the cleaning actions. For an already-closed IndexInput,
+     * the cleaning action is a no-op. For an open IndexInput, the close action
+     * will decrement a reference count.
+     */
+    private static final Cleaner CLEANER = Cleaner.create(OpenSearchExecutors.daemonThreadFactory(CLEANER_THREAD_NAME_PREFIX));
+
+    /**
+     * Start offset of the virtual file : non-zero in the slice case
+     */
+    protected final long offset;
+    /**
+     * Length of the virtual file, smaller than actual file size if it's a slice
+     */
+    protected final long length;
+
+    /**
+     * Whether this index input is a clone or otherwise the root file before slicing
+     */
+    protected final boolean isClone;
+
+    /**
+     * Variables used for block calculation and fetching. blockSize must be a
+     * power of two, and is defined as 2^blockShiftSize. blockMask is defined
+     * as blockSize - 1 and is used to calculate the offset within a block.
+     */
+    protected final int blockSizeShift;
+    protected final int blockSize;
+    protected final int blockMask;
+
+    /**
+     * ID of the current block
+     */
+    private int currentBlockId;
+
+    private final BlockHolder blockHolder = new BlockHolder();
+
+    OnDemandBlockIndexInput(Builder builder) {
+        super(builder.resourceDescription);
+        this.isClone = builder.isClone;
+        this.offset = builder.offset;
+        this.length = builder.length;
+        this.blockSizeShift = builder.blockSizeShift;
+        this.blockSize = builder.blockSize;
+        this.blockMask = builder.blockMask;
+        CLEANER.register(this, blockHolder);
+    }
+
+    /**
+     * Builds the actual sliced IndexInput (may apply extra offset in subclasses).
+     **/
+    protected abstract OnDemandBlockIndexInput buildSlice(String sliceDescription, long offset, long length);
+
+    /**
+     * Given a blockId, fetch it's IndexInput which might be partial/split/cloned one
+     * @param blockId to fetch for
+     * @return fetched IndexInput
+     */
+    protected abstract IndexInput fetchBlock(int blockId) throws IOException;
+
+    @Override
+    public abstract OnDemandBlockIndexInput clone();
+
+    @Override
+    public IndexInput slice(String sliceDescription, long offset, long length) throws IOException {
+        if (offset < 0 || length < 0 || offset + length > this.length()) {
+            throw new IllegalArgumentException(
+                "slice() "
+                    + sliceDescription
+                    + " out of bounds: offset="
+                    + offset
+                    + ",length="
+                    + length
+                    + ",fileLength="
+                    + this.length()
+                    + ": "
+                    + this
+            );
+        }
+
+        // The slice is seeked to the beginning.
+        return buildSlice(sliceDescription, offset, length);
+    }
+
+    @Override
+    public void close() throws IOException {
+        blockHolder.close();
+        currentBlockId = 0;
+    }
+
+    @Override
+    public long getFilePointer() {
+        if (blockHolder.block == null) return 0L;
+        return currentBlockStart() + currentBlockPosition() - offset;
+    }
+
+    @Override
+    public long length() {
+        return length;
+    }
+
+    @Override
+    public byte readByte() throws IOException {
+        if (blockHolder.block == null) {
+            // seek to the beginning
+            seek(0);
+        } else if (currentBlockPosition() >= blockSize) {
+            int blockId = currentBlockId + 1;
+            demandBlock(blockId);
+        }
+        return blockHolder.block.readByte();
+    }
+
+    @Override
+    public short readShort() throws IOException {
+        if (blockHolder.block != null && Short.BYTES <= (blockSize - currentBlockPosition())) {
+            return blockHolder.block.readShort();
+        } else {
+            return super.readShort();
+        }
+    }
+
+    @Override
+    public int readInt() throws IOException {
+        if (blockHolder.block != null && Integer.BYTES <= (blockSize - currentBlockPosition())) {
+            return blockHolder.block.readInt();
+        } else {
+            return super.readInt();
+        }
+    }
+
+    @Override
+    public long readLong() throws IOException {
+        if (blockHolder.block != null && Long.BYTES <= (blockSize - currentBlockPosition())) {
+            return blockHolder.block.readLong();
+        } else {
+            return super.readLong();
+        }
+    }
+
+    @Override
+    public final int readVInt() throws IOException {
+        if (blockHolder.block != null && 5 <= (blockSize - currentBlockPosition())) {
+            return blockHolder.block.readVInt();
+        } else {
+            return super.readVInt();
+        }
+    }
+
+    @Override
+    public final long readVLong() throws IOException {
+        if (blockHolder.block != null && 9 <= (blockSize - currentBlockPosition())) {
+            return blockHolder.block.readVLong();
+        } else {
+            return super.readVLong();
+        }
+    }
+
+    @Override
+    public void seek(long pos) throws IOException {
+        if (pos > length()) {
+            throw new EOFException("read past EOF: pos=" + pos + " vs length=" + length() + ": " + this);
+        }
+
+        seekInternal(pos + offset);
+    }
+
+    @Override
+    public final byte readByte(long pos) throws IOException {
+        // adjust the pos if it's sliced
+        pos = pos + offset;
+        if (blockHolder.block != null && isInCurrentBlockRange(pos)) {
+            // the block contains the byte
+            return ((RandomAccessInput) blockHolder.block).readByte(getBlockOffset(pos));
+        } else {
+            // the block does not have the byte, seek to the pos first
+            seekInternal(pos);
+            // then read the byte
+            return blockHolder.block.readByte();
+        }
+    }
+
+    @Override
+    public short readShort(long pos) throws IOException {
+        // adjust the pos if it's sliced
+        pos = pos + offset;
+        if (blockHolder.block != null && isInCurrentBlockRange(pos, Short.BYTES)) {
+            // the block contains enough data to satisfy this request
+            return ((RandomAccessInput) blockHolder.block).readShort(getBlockOffset(pos));
+        } else {
+            // the block does not have enough data, seek to the pos first
+            seekInternal(pos);
+            // then read the data
+            return super.readShort();
+        }
+    }
+
+    @Override
+    public int readInt(long pos) throws IOException {
+        // adjust the pos if it's sliced
+        pos = pos + offset;
+        if (blockHolder.block != null && isInCurrentBlockRange(pos, Integer.BYTES)) {
+            // the block contains enough data to satisfy this request
+            return ((RandomAccessInput) blockHolder.block).readInt(getBlockOffset(pos));
+        } else {
+            // the block does not have enough data, seek to the pos first
+            seekInternal(pos);
+            // then read the data
+            return super.readInt();
+        }
+    }
+
+    @Override
+    public long readLong(long pos) throws IOException {
+        // adjust the pos if it's sliced
+        pos = pos + offset;
+        if (blockHolder.block != null && isInCurrentBlockRange(pos, Long.BYTES)) {
+            // the block contains enough data to satisfy this request
+            return ((RandomAccessInput) blockHolder.block).readLong(getBlockOffset(pos));
+        } else {
+            // the block does not have enough data, seek to the pos first
+            seekInternal(pos);
+            // then read the data
+            return super.readLong();
+        }
+    }
+
+    @Override
+    public final void readBytes(byte[] b, int offset, int len) throws IOException {
+        if (blockHolder.block == null) {
+            // lazy seek to the beginning
+            seek(0);
+        }
+
+        int available = blockSize - currentBlockPosition();
+        if (len <= available) {
+            // the block contains enough data to satisfy this request
+            blockHolder.block.readBytes(b, offset, len);
+        } else {
+            // the block does not have enough data. First serve all we've got.
+            if (available > 0) {
+                blockHolder.block.readBytes(b, offset, available);
+                offset += available;
+                len -= available;
+            }
+
+            // and now, read the remaining 'len' bytes:
+            // len > blocksize example: FST <init>
+            while (len > 0) {
+                int blockId = currentBlockId + 1;
+                int toRead = Math.min(len, blockSize);
+                demandBlock(blockId);
+                blockHolder.block.readBytes(b, offset, toRead);
+                offset += toRead;
+                len -= toRead;
+            }
+        }
+
+    }
+
+    /**
+     * Seek to a block position, download the block if it's necessary
+     * NOTE: the pos should be an adjusted position for slices
+     */
+    private void seekInternal(long pos) throws IOException {
+        if (blockHolder.block == null || !isInCurrentBlockRange(pos)) {
+            demandBlock(getBlock(pos));
+        }
+        blockHolder.block.seek(getBlockOffset(pos));
+    }
+
+    /**
+     * Check if pos in current block range
+     * NOTE: the pos should be an adjusted position for slices
+     */
+    private boolean isInCurrentBlockRange(long pos) {
+        long offset = pos - currentBlockStart();
+        return offset >= 0 && offset < blockSize;
+    }
+
+    /**
+     * Check if [pos, pos + len) in current block range
+     * NOTE: the pos should be an adjusted position for slices
+     */
+    private boolean isInCurrentBlockRange(long pos, int len) {
+        long offset = pos - currentBlockStart();
+        return offset >= 0 && (offset + len) <= blockSize;
+    }
+
+    private void demandBlock(int blockId) throws IOException {
+        if (blockHolder.block != null && currentBlockId == blockId) return;
+
+        // close the current block before jumping to the new block
+        blockHolder.close();
+
+        blockHolder.set(fetchBlock(blockId));
+        currentBlockId = blockId;
+    }
+
+    protected void cloneBlock(OnDemandBlockIndexInput other) {
+        if (other.blockHolder.block != null) {
+            this.blockHolder.set(other.blockHolder.block.clone());
+            this.currentBlockId = other.currentBlockId;
+        }
+    }
+
+    protected int getBlock(long pos) {
+        return (int) (pos >>> blockSizeShift);
+    }
+
+    protected int getBlockOffset(long pos) {
+        return (int) (pos & blockMask);
+    }
+
+    protected long getBlockStart(int blockId) {
+        return (long) blockId << blockSizeShift;
+    }
+
+    protected long currentBlockStart() {
+        return getBlockStart(currentBlockId);
+    }
+
+    protected int currentBlockPosition() {
+        return (int) blockHolder.block.getFilePointer();
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static class Builder {
+        // Block size shift (default value is 23 == 2^23 == 8MiB)
+        public static final int DEFAULT_BLOCK_SIZE_SHIFT = 23;
+        public static final int DEFAULT_BLOCK_SIZE = 1 << DEFAULT_BLOCK_SIZE_SHIFT;;
+
+        private String resourceDescription;
+        private boolean isClone;
+        private long offset;
+        private long length;
+        private int blockSizeShift = DEFAULT_BLOCK_SIZE_SHIFT;
+        private int blockSize = 1 << blockSizeShift;
+        private int blockMask = blockSize - 1;
+
+        private Builder() {}
+
+        public Builder resourceDescription(String resourceDescription) {
+            this.resourceDescription = resourceDescription;
+            return this;
+        }
+
+        public Builder isClone(boolean clone) {
+            isClone = clone;
+            return this;
+        }
+
+        public Builder offset(long offset) {
+            this.offset = offset;
+            return this;
+        }
+
+        public Builder length(long length) {
+            this.length = length;
+            return this;
+        }
+
+        Builder blockSizeShift(int blockSizeShift) {
+            assert blockSizeShift < 31 : "blockSizeShift must be < 31";
+            this.blockSizeShift = blockSizeShift;
+            this.blockSize = 1 << blockSizeShift;
+            this.blockMask = blockSize - 1;
+            return this;
+        }
+    }
+
+    /**
+     * Simple class to hold the currently open IndexInput backing an instance
+     * of an {@link OnDemandBlockIndexInput}. Lucene may clone one of these
+     * instances, and per the contract[1], the clones will never be closed.
+     * However, closing the instances is critical for our reference counting.
+     * Therefore, we are using the {@link Cleaner} mechanism from the JDK to
+     * close these clones when they become phantom reachable. The clean action
+     * must not hold a reference to the {@link OnDemandBlockIndexInput} itself
+     * (otherwise it would never become phantom reachable!) so we need a wrapper
+     * instance to hold the current underlying IndexInput, while allowing it to
+     * be changed out with different instances as {@link OnDemandBlockIndexInput}
+     * reads through the data.
+     *
+     * This class implements {@link Runnable} so that it can be passed directly
+     * to the cleaner to run its close action.
+     *
+     * [1]: https://github.com/apache/lucene/blob/8340b01c3cc229f33584ce2178b07b8984daa6a9/lucene/core/src/java/org/apache/lucene/store/IndexInput.java#L32-L33
+     */
+    private static class BlockHolder implements Closeable, Runnable {
+        private volatile IndexInput block;
+
+        private void set(IndexInput block) {
+            if (this.block != null) {
+                throw new IllegalStateException("Previous block was not closed!");
+            }
+            this.block = Objects.requireNonNull(block);
+        }
+
+        @Override
+        public void close() throws IOException {
+            if (block != null) {
+                block.close();
+                block = null;
+            }
+        }
+
+        @Override
+        public void run() {
+            try {
+                close();
+            } catch (IOException e) {
+                // Exceptions thrown in the cleaning action are ignored,
+                // so log and swallow the exception here
+                logger.info("Exception thrown while closing block owned by phantom reachable instance", e);
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInput.java b/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInput.java
new file mode 100644
index 0000000000000..b3f8ee9c1817e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInput.java
@@ -0,0 +1,161 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.file;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.FSDirectory;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot.FileInfo;
+import org.opensearch.index.store.remote.utils.BlobFetchRequest;
+import org.opensearch.index.store.remote.utils.TransferManager;
+
+import java.io.IOException;
+
+/**
+ * This is an implementation of {@link OnDemandBlockIndexInput} where this class provides the main IndexInput using shard snapshot files.
+ * <br>
+ * This class rely on {@link TransferManager} to really fetch the snapshot files from the remote blob store and maybe cache them
+ *
+ * @opensearch.internal
+ */
+public class OnDemandBlockSnapshotIndexInput extends OnDemandBlockIndexInput {
+    private static final Logger logger = LogManager.getLogger(OnDemandBlockSnapshotIndexInput.class);
+
+    /**
+     * Where this class fetches IndexInput parts from
+     */
+    final TransferManager transferManager;
+
+    /**
+     * FileInfo contains snapshot metadata references for this IndexInput
+     */
+    protected final FileInfo fileInfo;
+
+    /**
+     * Underlying lucene directory to open blocks and for caching
+     */
+    protected final FSDirectory directory;
+    /**
+     * File Name
+     */
+    protected final String fileName;
+
+    /**
+     * part size  in bytes
+     */
+    protected final long partSize;
+
+    /**
+     * Size of the file, larger than length if it's a slice
+     */
+    protected final long originalFileSize;
+
+    public OnDemandBlockSnapshotIndexInput(FileInfo fileInfo, FSDirectory directory, TransferManager transferManager) {
+        this(
+            "BlockedSnapshotIndexInput(path=\""
+                + directory.getDirectory().toString()
+                + "/"
+                + fileInfo.physicalName()
+                + "\", "
+                + "offset="
+                + 0
+                + ", length= "
+                + fileInfo.length()
+                + ")",
+            fileInfo,
+            0L,
+            fileInfo.length(),
+            false,
+            directory,
+            transferManager
+        );
+    }
+
+    public OnDemandBlockSnapshotIndexInput(
+        String resourceDescription,
+        FileInfo fileInfo,
+        long offset,
+        long length,
+        boolean isClone,
+        FSDirectory directory,
+        TransferManager transferManager
+    ) {
+        this(
+            OnDemandBlockIndexInput.builder().resourceDescription(resourceDescription).isClone(isClone).offset(offset).length(length),
+            fileInfo,
+            directory,
+            transferManager
+        );
+    }
+
+    OnDemandBlockSnapshotIndexInput(
+        OnDemandBlockIndexInput.Builder builder,
+        FileInfo fileInfo,
+        FSDirectory directory,
+        TransferManager transferManager
+    ) {
+        super(builder);
+        this.transferManager = transferManager;
+        this.fileInfo = fileInfo;
+        this.partSize = fileInfo.partSize().getBytes();
+        this.fileName = fileInfo.physicalName();
+        this.directory = directory;
+        this.originalFileSize = fileInfo.length();
+    }
+
+    @Override
+    protected OnDemandBlockSnapshotIndexInput buildSlice(String sliceDescription, long offset, long length) {
+        return new OnDemandBlockSnapshotIndexInput(
+            OnDemandBlockIndexInput.builder()
+                .blockSizeShift(blockSizeShift)
+                .isClone(true)
+                .offset(this.offset + offset)
+                .length(length)
+                .resourceDescription(sliceDescription),
+            fileInfo,
+            directory,
+            transferManager
+        );
+    }
+
+    @Override
+    protected IndexInput fetchBlock(int blockId) throws IOException {
+        final String blockFileName = fileName + "." + blockId;
+
+        final long blockStart = getBlockStart(blockId);
+        final long blockEnd = blockStart + getActualBlockSize(blockId);
+        final int part = (int) (blockStart / partSize);
+        final long partStart = part * partSize;
+
+        final long position = blockStart - partStart;
+        final long length = blockEnd - blockStart;
+
+        BlobFetchRequest blobFetchRequest = BlobFetchRequest.builder()
+            .position(position)
+            .length(length)
+            .blobName(fileInfo.partName(part))
+            .directory(directory)
+            .fileName(blockFileName)
+            .build();
+        return transferManager.fetchBlob(blobFetchRequest);
+    }
+
+    @Override
+    public OnDemandBlockSnapshotIndexInput clone() {
+        OnDemandBlockSnapshotIndexInput clone = buildSlice("clone", 0L, this.length);
+        // ensures that clones may be positioned at the same point as the blocked file they were cloned from
+        clone.cloneBlock(this);
+        return clone;
+    }
+
+    protected long getActualBlockSize(int blockId) {
+        return (blockId != getBlock(originalFileSize - 1)) ? blockSize : getBlockOffset(originalFileSize - 1) + 1;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/file/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/file/package-info.java
new file mode 100644
index 0000000000000..469df9a2f893f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/file/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing classes to abstract IndexInput as on demand blocked (partitioned) files and as a remote blob store backed
+ */
+package org.opensearch.index.store.remote.file;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/CachedIndexInput.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/CachedIndexInput.java
new file mode 100644
index 0000000000000..a29598dbee505
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/CachedIndexInput.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+
+import java.io.IOException;
+
+/**
+ * Interface for an entry in the {@link FileCache} that can return an
+ * {@link IndexInput}. Exactly how the IndexInput is created is determined by
+ * the implementations.
+ *
+ * @opensearch.internal
+ */
+public interface CachedIndexInput extends AutoCloseable {
+    /**
+     * Gets the {@link IndexInput} this cache entry represents.
+     * @return The IndexInput
+     * @throws IOException if any I/O error occurs
+     */
+    IndexInput getIndexInput() throws IOException;
+
+    /**
+     * @return length in bytes
+     */
+    long length();
+
+    /**
+     * @return true if the entry is closed, false otherwise
+     */
+    boolean isClosed();
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCache.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCache.java
new file mode 100644
index 0000000000000..dbbbbecbc6afd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCache.java
@@ -0,0 +1,259 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.index.store.remote.utils.cache.CacheUsage;
+import org.opensearch.index.store.remote.utils.cache.RefCountedCache;
+import org.opensearch.index.store.remote.utils.cache.SegmentedCache;
+import org.opensearch.index.store.remote.utils.cache.stats.CacheStats;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Predicate;
+
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory.LOCAL_STORE_LOCATION;
+
+/**
+ * File Cache (FC) is introduced to solve the problem that the local disk cannot hold
+ * the entire dataset on remote store. It maintains a node level view of index files with priorities,
+ * caching only those index files needed by queries. The file with the lowest priority
+ * (Least Recently Used) in the FC is replaced first.
+ *
+ * <p>The two main interfaces of FC are put and get. When a new file index input is added
+ * to the file cache, the file will be added at cache head, which means it has the highest
+ * priority.
+ * <p> The get function does not add file to cache, but it promotes the priority
+ * of a given file (since it makes it the most recently used).
+ *
+ * <p>Once file cache reaches its capacity, it starts evictions. Eviction removes the file
+ * items from cache tail and triggers a callback to clean up the file from disk. The
+ * cleanup process also includes closing file’s descriptor.
+ *
+ * @opensearch.internal
+ */
+public class FileCache implements RefCountedCache<Path, CachedIndexInput> {
+    private final SegmentedCache<Path, CachedIndexInput> theCache;
+
+    private final CircuitBreaker circuitBreaker;
+
+    /**
+     * Defines a limit of how much total remote data can be referenced as a ratio of the size of the disk reserved for
+     * the file cache. For example, if 100GB disk space is configured for use as a file cache and the
+     * remote_data_ratio of 5 is defined, then a total of 500GB of remote data can be loaded as searchable snapshots.
+     * This is designed to be a safeguard to prevent oversubscribing a cluster.
+     * Specify a value of zero for no limit, which is the default for compatibility reasons.
+     */
+    public static final Setting<Double> DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING = Setting.doubleSetting(
+        "cluster.filecache.remote_data_ratio",
+        0.0,
+        0.0,
+        Setting.Property.NodeScope,
+        Setting.Property.Dynamic
+    );
+
+    public FileCache(SegmentedCache<Path, CachedIndexInput> cache, CircuitBreaker circuitBreaker) {
+        this.theCache = cache;
+        this.circuitBreaker = circuitBreaker;
+    }
+
+    public long capacity() {
+        return theCache.capacity();
+    }
+
+    @Override
+    public CachedIndexInput put(Path filePath, CachedIndexInput indexInput) {
+        CachedIndexInput cachedIndexInput = theCache.put(filePath, indexInput);
+        checkParentBreaker(filePath);
+        return cachedIndexInput;
+    }
+
+    @Override
+    public CachedIndexInput compute(
+        Path key,
+        BiFunction<? super Path, ? super CachedIndexInput, ? extends CachedIndexInput> remappingFunction
+    ) {
+        CachedIndexInput cachedIndexInput = theCache.compute(key, remappingFunction);
+        checkParentBreaker(key);
+        return cachedIndexInput;
+    }
+
+    /**
+     * Given a file path, gets the corresponding file index input from FileCache.
+     * This API also updates the priority for the given file
+     *
+     * @param filePath given file path
+     * @return corresponding file index input from FileCache.
+     */
+    public CachedIndexInput get(Path filePath) {
+        return theCache.get(filePath);
+    }
+
+    /**
+     * Given a file path, remove the file from cache.
+     * Even if the file is pinned or it's still in use, the reclaim
+     * still take effect.
+     *
+     * @param filePath given file path
+     */
+    public void remove(final Path filePath) {
+        theCache.remove(filePath);
+    }
+
+    @Override
+    public void clear() {
+        theCache.clear();
+    }
+
+    @Override
+    public long size() {
+        return theCache.size();
+    }
+
+    @Override
+    public void incRef(Path key) {
+        theCache.incRef(key);
+    }
+
+    @Override
+    public void decRef(Path key) {
+        theCache.decRef(key);
+    }
+
+    @Override
+    public long prune() {
+        return theCache.prune();
+    }
+
+    @Override
+    public long prune(Predicate<Path> keyPredicate) {
+        return theCache.prune(keyPredicate);
+    }
+
+    @Override
+    public CacheUsage usage() {
+        return theCache.usage();
+    }
+
+    @Override
+    public CacheStats stats() {
+        return theCache.stats();
+    }
+
+    /**
+     * Ensures that the PARENT breaker is not tripped when an entry is added to the cache
+     * @param filePath the path key for which entry is added
+     */
+    private void checkParentBreaker(Path filePath) {
+        try {
+            circuitBreaker.addEstimateBytesAndMaybeBreak(0, "filecache_entry");
+        } catch (CircuitBreakingException ex) {
+            theCache.remove(filePath);
+            throw new CircuitBreakingException(
+                "Unable to create file cache entries",
+                ex.getBytesWanted(),
+                ex.getByteLimit(),
+                ex.getDurability()
+            );
+        }
+    }
+
+    /**
+     * Restores the file cache instance performing a folder scan of the
+     * {@link org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory#LOCAL_STORE_LOCATION}
+     * directory within the provided file cache path.
+     */
+    public void restoreFromDirectory(List<Path> fileCacheDataPaths) {
+        fileCacheDataPaths.stream()
+            .filter(Files::isDirectory)
+            .map(path -> path.resolve(LOCAL_STORE_LOCATION))
+            .filter(Files::isDirectory)
+            .flatMap(dir -> {
+                try {
+                    return Files.list(dir);
+                } catch (IOException e) {
+                    throw new UncheckedIOException(
+                        "Unable to process file cache directory. Please clear the file cache for node startup.",
+                        e
+                    );
+                }
+            })
+            .filter(Files::isRegularFile)
+            .forEach(path -> {
+                try {
+                    put(path.toAbsolutePath(), new RestoredCachedIndexInput(Files.size(path)));
+                    decRef(path.toAbsolutePath());
+                } catch (IOException e) {
+                    throw new UncheckedIOException(
+                        "Unable to retrieve cache file details. Please clear the file cache for node startup.",
+                        e
+                    );
+                }
+            });
+    }
+
+    /**
+     * Returns the current {@link FileCacheStats}
+     */
+    public FileCacheStats fileCacheStats() {
+        CacheStats stats = stats();
+        CacheUsage usage = usage();
+        return new FileCacheStats(
+            System.currentTimeMillis(),
+            usage.activeUsage(),
+            capacity(),
+            usage.usage(),
+            stats.evictionWeight(),
+            stats.hitCount(),
+            stats.missCount()
+        );
+    }
+
+    /**
+     * Placeholder for the existing file blocks that are in the disk-based
+     * local cache at node startup time. We can't open a file handle to these
+     * blocks at this point, so we store this placeholder object in the cache.
+     * If a block is needed, then these entries will be replaced with a proper
+     * entry that will open the actual file handle to create the IndexInput.
+     * These entries are eligible for eviction so if nothing needs to reference
+     * them they will be deleted when the disk-based local cache fills up.
+     */
+    private static class RestoredCachedIndexInput implements CachedIndexInput {
+        private final long length;
+
+        private RestoredCachedIndexInput(long length) {
+            this.length = length;
+        }
+
+        @Override
+        public IndexInput getIndexInput() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public long length() {
+            return length;
+        }
+
+        @Override
+        public boolean isClosed() {
+            return true;
+        }
+
+        @Override
+        public void close() throws Exception {}
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheCleaner.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheCleaner.java
new file mode 100644
index 0000000000000..fb89e651e7616
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheCleaner.java
@@ -0,0 +1,108 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.IndexEventListener;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.indices.cluster.IndicesClusterStateService;
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory.LOCAL_STORE_LOCATION;
+
+/**
+ * IndexEventListener to clean up file cache when the index is deleted. The cached entries will be eligible
+ * for eviction when the shard is deleted, but this listener deterministically removes entries from memory and
+ * from disk at the time of shard deletion as opposed to waiting for the cache to need to perform eviction.
+ *
+ * @opensearch.internal
+ */
+public class FileCacheCleaner implements IndexEventListener {
+    private static final Logger log = LogManager.getLogger(FileCacheCleaner.class);
+
+    private final NodeEnvironment nodeEnvironment;
+    private final FileCache fileCache;
+
+    public FileCacheCleaner(NodeEnvironment nodeEnvironment, FileCache fileCache) {
+        this.nodeEnvironment = nodeEnvironment;
+        this.fileCache = fileCache;
+    }
+
+    /**
+     * before shard deleted and after shard closed, cleans up the corresponding index file path entries from FC.
+     * @param shardId  The shard id
+     * @param settings the shards index settings
+     */
+    @Override
+    public void beforeIndexShardDeleted(ShardId shardId, Settings settings) {
+        try {
+            if (isRemoteSnapshot(settings)) {
+                final ShardPath shardPath = ShardPath.loadFileCachePath(nodeEnvironment, shardId);
+                final Path localStorePath = shardPath.getDataPath().resolve(LOCAL_STORE_LOCATION);
+                try (DirectoryStream<Path> ds = Files.newDirectoryStream(localStorePath)) {
+                    for (Path subPath : ds) {
+                        fileCache.remove(subPath.toRealPath());
+                    }
+                }
+            }
+        } catch (IOException ioe) {
+            log.error(() -> new ParameterizedMessage("Error removing items from cache during shard deletion {}", shardId), ioe);
+        }
+    }
+
+    @Override
+    public void afterIndexShardDeleted(ShardId shardId, Settings settings) {
+        if (isRemoteSnapshot(settings)) {
+            final Path path = ShardPath.loadFileCachePath(nodeEnvironment, shardId).getDataPath();
+            try {
+                if (Files.exists(path)) {
+                    IOUtils.rm(path);
+                }
+            } catch (IOException e) {
+                log.error(() -> new ParameterizedMessage("Failed to delete cache path for shard {}", shardId), e);
+            }
+        }
+    }
+
+    @Override
+    public void afterIndexRemoved(
+        Index index,
+        IndexSettings indexSettings,
+        IndicesClusterStateService.AllocatedIndices.IndexRemovalReason reason
+    ) {
+        if (isRemoteSnapshot(indexSettings.getSettings())
+            && reason == IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.DELETED) {
+            final Path indexCachePath = nodeEnvironment.fileCacheNodePath().fileCachePath.resolve(index.getUUID());
+            if (Files.exists(indexCachePath)) {
+                try {
+                    IOUtils.rm(indexCachePath);
+                } catch (IOException e) {
+                    log.error(() -> new ParameterizedMessage("Failed to delete cache path for index {}", index), e);
+                }
+            }
+        }
+    }
+
+    private static boolean isRemoteSnapshot(Settings settings) {
+        return IndexModule.Type.REMOTE_SNAPSHOT.match(settings.get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey()));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheFactory.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheFactory.java
new file mode 100644
index 0000000000000..9fe67dc67020a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheFactory.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.opensearch.common.cache.RemovalReason;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.index.store.remote.utils.cache.SegmentedCache;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.opensearch.ExceptionsHelper.catchAsRuntimeException;
+
+/**
+ * File Cache (FC) is introduced to solve the problem that the local disk cannot hold
+ * the entire dataset on remote store. It maintains a node level view of index files with priorities,
+ * caching only those index files needed by queries. The file with the lowest priority
+ * (Least Recently Used) in the FC is replaced first.
+ *
+ * <p>The two main interfaces of FC are put and get. When a new file index input is added
+ * to the file cache, the file will be added at cache head, which means it has the highest
+ * priority.
+ * <p> The get function does not add file to cache, but it promotes the priority
+ * of a given file (since it makes it the most recently used).
+ *
+ * <p>Once file cache reaches its capacity, it starts evictions. Eviction removes the file
+ * items from cache tail and triggers a callback to clean up the file from disk. The
+ * cleanup process also includes closing file’s descriptor.
+ *
+ * @opensearch.internal
+ */
+public class FileCacheFactory {
+
+    public static FileCache createConcurrentLRUFileCache(long capacity, CircuitBreaker circuitBreaker) {
+        return new FileCache(createDefaultBuilder().capacity(capacity).build(), circuitBreaker);
+    }
+
+    public static FileCache createConcurrentLRUFileCache(long capacity, int concurrencyLevel, CircuitBreaker circuitBreaker) {
+        return new FileCache(createDefaultBuilder().capacity(capacity).concurrencyLevel(concurrencyLevel).build(), circuitBreaker);
+    }
+
+    private static SegmentedCache.Builder<Path, CachedIndexInput> createDefaultBuilder() {
+        return SegmentedCache.<Path, CachedIndexInput>builder()
+            // use length in bytes as the weight of the file item
+            .weigher(CachedIndexInput::length)
+            .listener((removalNotification) -> {
+                RemovalReason removalReason = removalNotification.getRemovalReason();
+                CachedIndexInput value = removalNotification.getValue();
+                Path key = removalNotification.getKey();
+                if (removalReason != RemovalReason.REPLACED) {
+                    catchAsRuntimeException(value::close);
+                    catchAsRuntimeException(() -> Files.deleteIfExists(key));
+                }
+            });
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheStats.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheStats.java
new file mode 100644
index 0000000000000..ebb6202c86ec9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheStats.java
@@ -0,0 +1,148 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Statistics on file cache
+ *
+ * @opensearch.internal
+ */
+public class FileCacheStats implements Writeable, ToXContentFragment {
+
+    private final long timestamp;
+    private final long active;
+    private final long total;
+    private final long used;
+    private final long evicted;
+    private final long hits;
+    private final long misses;
+
+    public FileCacheStats(
+        final long timestamp,
+        final long active,
+        final long total,
+        final long used,
+        final long evicted,
+        final long hits,
+        final long misses
+    ) {
+        this.timestamp = timestamp;
+        this.active = active;
+        this.total = total;
+        this.used = used;
+        this.evicted = evicted;
+        this.hits = hits;
+        this.misses = misses;
+    }
+
+    public FileCacheStats(final StreamInput in) throws IOException {
+        this.timestamp = in.readLong();
+        this.active = in.readLong();
+        this.total = in.readLong();
+        this.used = in.readLong();
+        this.evicted = in.readLong();
+        this.hits = in.readLong();
+        this.misses = in.readLong();
+    }
+
+    public static short calculatePercentage(long used, long max) {
+        return max <= 0 ? 0 : (short) (Math.round((100d * used) / max));
+    }
+
+    @Override
+    public void writeTo(final StreamOutput out) throws IOException {
+        out.writeLong(timestamp);
+        out.writeLong(active);
+        out.writeLong(total);
+        out.writeLong(used);
+        out.writeLong(evicted);
+        out.writeLong(hits);
+        out.writeLong(misses);
+    }
+
+    public long getTimestamp() {
+        return timestamp;
+    }
+
+    public ByteSizeValue getTotal() {
+        return new ByteSizeValue(total);
+    }
+
+    public ByteSizeValue getActive() {
+        return new ByteSizeValue(active);
+    }
+
+    public short getActivePercent() {
+        return calculatePercentage(active, used);
+    }
+
+    public ByteSizeValue getUsed() {
+        return new ByteSizeValue(used);
+    }
+
+    public short getUsedPercent() {
+        return calculatePercentage(getUsed().getBytes(), total);
+    }
+
+    public ByteSizeValue getEvicted() {
+        return new ByteSizeValue(evicted);
+    }
+
+    public long getCacheHits() {
+        return hits;
+    }
+
+    public long getCacheMisses() {
+        return misses;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(Fields.FILE_CACHE);
+        builder.field(Fields.TIMESTAMP, getTimestamp());
+        builder.humanReadableField(Fields.ACTIVE_IN_BYTES, Fields.ACTIVE, getActive());
+        builder.humanReadableField(Fields.TOTAL_IN_BYTES, Fields.TOTAL, getTotal());
+        builder.humanReadableField(Fields.USED_IN_BYTES, Fields.USED, getUsed());
+        builder.humanReadableField(Fields.EVICTIONS_IN_BYTES, Fields.EVICTIONS, getEvicted());
+        builder.field(Fields.ACTIVE_PERCENT, getActivePercent());
+        builder.field(Fields.USED_PERCENT, getUsedPercent());
+        builder.field(Fields.HIT_COUNT, getCacheHits());
+        builder.field(Fields.MISS_COUNT, getCacheMisses());
+        builder.endObject();
+        return builder;
+    }
+
+    static final class Fields {
+        static final String FILE_CACHE = "file_cache";
+        static final String TIMESTAMP = "timestamp";
+        static final String ACTIVE = "active";
+        static final String ACTIVE_IN_BYTES = "active_in_bytes";
+        static final String USED = "used";
+        static final String USED_IN_BYTES = "used_in_bytes";
+        static final String EVICTIONS = "evictions";
+        static final String EVICTIONS_IN_BYTES = "evictions_in_bytes";
+        static final String TOTAL = "total";
+        static final String TOTAL_IN_BYTES = "total_in_bytes";
+
+        static final String ACTIVE_PERCENT = "active_percent";
+        static final String USED_PERCENT = "used_percent";
+
+        static final String HIT_COUNT = "hit_count";
+        static final String MISS_COUNT = "miss_count";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCachedIndexInput.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCachedIndexInput.java
new file mode 100644
index 0000000000000..7d7c40be3a833
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/FileCachedIndexInput.java
@@ -0,0 +1,154 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.RandomAccessInput;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+/**
+ * Reference Counted IndexInput. The first FileCachedIndexInput for a file/block is called origin.
+ * origin never references to itself, so the RC = 0 when origin is created.
+ * Every time there is a clone to the origin, RC + 1.
+ * Every time a clone is closed, RC - 1.
+ * When there is an eviction in FileCache, it only cleanups those origins with RC = 0.
+ *
+ * @opensearch.internal
+ */
+public class FileCachedIndexInput extends IndexInput implements RandomAccessInput {
+
+    protected final FileCache cache;
+
+    /**
+     * on disk file path of this index input
+     */
+    protected Path filePath;
+
+    /**
+     * underlying lucene index input which this IndexInput
+     * delegate all its read functions to.
+     */
+    protected IndexInput luceneIndexInput;
+
+    /** indicates if this IndexInput instance is a clone or not */
+    private final boolean isClone;
+
+    private volatile boolean closed = false;
+
+    public FileCachedIndexInput(FileCache cache, Path filePath, IndexInput underlyingIndexInput) {
+        this(cache, filePath, underlyingIndexInput, false);
+    }
+
+    FileCachedIndexInput(FileCache cache, Path filePath, IndexInput underlyingIndexInput, boolean isClone) {
+        super("FileCachedIndexInput (path=" + filePath.toString() + ")");
+        this.cache = cache;
+        this.filePath = filePath;
+        this.luceneIndexInput = underlyingIndexInput;
+        this.isClone = isClone;
+    }
+
+    @Override
+    public long getFilePointer() {
+        return luceneIndexInput.getFilePointer();
+    }
+
+    @Override
+    public void seek(long pos) throws IOException {
+        luceneIndexInput.seek(pos);
+    }
+
+    @Override
+    public long length() {
+        return luceneIndexInput.length();
+    }
+
+    @Override
+    public byte readByte() throws IOException {
+        return luceneIndexInput.readByte();
+    }
+
+    @Override
+    public short readShort() throws IOException {
+        return luceneIndexInput.readShort();
+    }
+
+    @Override
+    public int readInt() throws IOException {
+        return luceneIndexInput.readInt();
+    }
+
+    @Override
+    public long readLong() throws IOException {
+        return luceneIndexInput.readLong();
+    }
+
+    @Override
+    public final int readVInt() throws IOException {
+        return luceneIndexInput.readVInt();
+    }
+
+    @Override
+    public final long readVLong() throws IOException {
+        return luceneIndexInput.readVLong();
+    }
+
+    @Override
+    public void readBytes(byte[] b, int offset, int len) throws IOException {
+        luceneIndexInput.readBytes(b, offset, len);
+    }
+
+    @Override
+    public byte readByte(long pos) throws IOException {
+        return ((RandomAccessInput) luceneIndexInput).readByte(pos);
+    }
+
+    @Override
+    public short readShort(long pos) throws IOException {
+        return ((RandomAccessInput) luceneIndexInput).readShort(pos);
+    }
+
+    @Override
+    public int readInt(long pos) throws IOException {
+        return ((RandomAccessInput) luceneIndexInput).readInt(pos);
+    }
+
+    @Override
+    public long readLong(long pos) throws IOException {
+        return ((RandomAccessInput) luceneIndexInput).readLong(pos);
+    }
+
+    @Override
+    public FileCachedIndexInput clone() {
+        cache.incRef(filePath);
+        return new FileCachedIndexInput(cache, filePath, luceneIndexInput.clone(), true);
+    }
+
+    @Override
+    public IndexInput slice(String sliceDescription, long offset, long length) throws IOException {
+        // never reach here!
+        throw new UnsupportedOperationException("FileCachedIndexInput couldn't be sliced.");
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (!closed) {
+            // if the underlying lucene index input is a clone,
+            // the following line won't close/unmap the file.
+            luceneIndexInput.close();
+            luceneIndexInput = null;
+            // origin never reference it itself, only clone needs decRef here
+            if (isClone) {
+                cache.decRef(filePath);
+            }
+            closed = true;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/filecache/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/filecache/package-info.java
new file mode 100644
index 0000000000000..1644ce387c21f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/filecache/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains class used for File System Caching for remote store
+ */
+package org.opensearch.index.store.remote.filecache;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadata.java b/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadata.java
new file mode 100644
index 0000000000000..1cec20ec3f6cc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadata.java
@@ -0,0 +1,165 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.metadata;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.util.Version;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * Metadata object for Remote Segment
+ *
+ * @opensearch.internal
+ */
+public class RemoteSegmentMetadata {
+    /**
+     * Latest supported version of metadata
+     */
+    public static final int CURRENT_VERSION = 1;
+    /**
+     * Metadata codec
+     */
+    public static final String METADATA_CODEC = "segment_md";
+
+    /**
+     * Data structure holding metadata content
+     */
+    private final Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> metadata;
+
+    private final byte[] segmentInfosBytes;
+
+    private final ReplicationCheckpoint replicationCheckpoint;
+
+    public RemoteSegmentMetadata(
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> metadata,
+        byte[] segmentInfosBytes,
+        ReplicationCheckpoint replicationCheckpoint
+    ) {
+        this.metadata = metadata;
+        this.segmentInfosBytes = segmentInfosBytes;
+        this.replicationCheckpoint = replicationCheckpoint;
+    }
+
+    /**
+     * Exposes underlying metadata content data structure.
+     * @return {@code metadata}
+     */
+    public Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> getMetadata() {
+        return this.metadata;
+    }
+
+    public byte[] getSegmentInfosBytes() {
+        return segmentInfosBytes;
+    }
+
+    public long getGeneration() {
+        return replicationCheckpoint.getSegmentsGen();
+    }
+
+    public long getPrimaryTerm() {
+        return replicationCheckpoint.getPrimaryTerm();
+    }
+
+    public ReplicationCheckpoint getReplicationCheckpoint() {
+        return replicationCheckpoint;
+    }
+
+    /**
+     * Generate {@code Map<String, String>} from {@link RemoteSegmentMetadata}
+     * @return {@code Map<String, String>}
+     */
+    public Map<String, String> toMapOfStrings() {
+        return this.metadata.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, entry -> entry.getValue().toString()));
+    }
+
+    /**
+     * Generate {@link RemoteSegmentMetadata} from {@code segmentMetadata}
+     * @param segmentMetadata metadata content in the form of {@code Map<String, String>}
+     * @return {@link RemoteSegmentMetadata}
+     */
+    public static Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> fromMapOfStrings(Map<String, String> segmentMetadata) {
+        return segmentMetadata.entrySet()
+            .stream()
+            .collect(
+                Collectors.toMap(
+                    Map.Entry::getKey,
+                    entry -> RemoteSegmentStoreDirectory.UploadedSegmentMetadata.fromString(entry.getValue())
+                )
+            );
+    }
+
+    public void write(IndexOutput out) throws IOException {
+        out.writeMapOfStrings(toMapOfStrings());
+        writeCheckpointToIndexOutput(replicationCheckpoint, out);
+        out.writeLong(segmentInfosBytes.length);
+        out.writeBytes(segmentInfosBytes, segmentInfosBytes.length);
+    }
+
+    public static RemoteSegmentMetadata read(IndexInput indexInput) throws IOException {
+        Map<String, String> metadata = indexInput.readMapOfStrings();
+        final Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegmentMetadataMap = RemoteSegmentMetadata
+            .fromMapOfStrings(metadata);
+        ReplicationCheckpoint replicationCheckpoint = readCheckpointFromIndexInput(indexInput, uploadedSegmentMetadataMap);
+        int byteArraySize = (int) indexInput.readLong();
+        byte[] segmentInfosBytes = new byte[byteArraySize];
+        indexInput.readBytes(segmentInfosBytes, 0, byteArraySize);
+        return new RemoteSegmentMetadata(uploadedSegmentMetadataMap, segmentInfosBytes, replicationCheckpoint);
+    }
+
+    public static void writeCheckpointToIndexOutput(ReplicationCheckpoint replicationCheckpoint, IndexOutput out) throws IOException {
+        ShardId shardId = replicationCheckpoint.getShardId();
+        // Write ShardId
+        out.writeString(shardId.getIndex().getName());
+        out.writeString(shardId.getIndex().getUUID());
+        out.writeVInt(shardId.getId());
+        // Write remaining checkpoint fields
+        out.writeLong(replicationCheckpoint.getPrimaryTerm());
+        out.writeLong(replicationCheckpoint.getSegmentsGen());
+        out.writeLong(replicationCheckpoint.getSegmentInfosVersion());
+        out.writeLong(replicationCheckpoint.getLength());
+        out.writeString(replicationCheckpoint.getCodec());
+    }
+
+    private static ReplicationCheckpoint readCheckpointFromIndexInput(
+        IndexInput in,
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegmentMetadataMap
+    ) throws IOException {
+        return new ReplicationCheckpoint(
+            new ShardId(new Index(in.readString(), in.readString()), in.readVInt()),
+            in.readLong(),
+            in.readLong(),
+            in.readLong(),
+            in.readLong(),
+            in.readString(),
+            toStoreFileMetadata(uploadedSegmentMetadataMap)
+        );
+    }
+
+    private static Map<String, StoreFileMetadata> toStoreFileMetadata(
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> metadata
+    ) {
+        return metadata.entrySet()
+            .stream()
+            // TODO: Version here should be read from UploadedSegmentMetadata.
+            .map(
+                entry -> new StoreFileMetadata(entry.getKey(), entry.getValue().getLength(), entry.getValue().getChecksum(), Version.LATEST)
+            )
+            .collect(Collectors.toMap(StoreFileMetadata::name, Function.identity()));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandler.java b/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandler.java
new file mode 100644
index 0000000000000..3077d8c76ddae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandler.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.metadata;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.common.io.IndexIOStreamHandler;
+
+import java.io.IOException;
+
+/**
+ * Handler for {@link RemoteSegmentMetadata}
+ *
+ * @opensearch.internal
+ */
+public class RemoteSegmentMetadataHandler implements IndexIOStreamHandler<RemoteSegmentMetadata> {
+    /**
+     * Reads metadata content from metadata file input stream and parsed into {@link RemoteSegmentMetadata}
+     * @param indexInput metadata file input stream with {@link IndexInput#getFilePointer()} pointing to metadata content
+     * @return {@link RemoteSegmentMetadata}
+     */
+    @Override
+    public RemoteSegmentMetadata readContent(IndexInput indexInput) throws IOException {
+        return RemoteSegmentMetadata.read(indexInput);
+    }
+
+    /**
+     * Writes metadata to file output stream
+     * @param indexOutput metadata file input stream
+     * @param content {@link RemoteSegmentMetadata} from which metadata content would be generated
+     */
+    @Override
+    public void writeContent(IndexOutput indexOutput, RemoteSegmentMetadata content) throws IOException {
+        content.write(indexOutput);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/metadata/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/metadata/package-info.java
new file mode 100644
index 0000000000000..da0444af4c246
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/metadata/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing metadata constructs for Remote Segment store
+ */
+package org.opensearch.index.store.remote.metadata;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/package-info.java
new file mode 100644
index 0000000000000..69e01748a5231
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing classes to abstract access to index input as an on-demand block files and as remote stored files
+ */
+package org.opensearch.index.store.remote;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/BlobFetchRequest.java b/server/src/main/java/org/opensearch/index/store/remote/utils/BlobFetchRequest.java
new file mode 100644
index 0000000000000..d0508e9c6f4c7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/BlobFetchRequest.java
@@ -0,0 +1,136 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FSDirectory;
+
+import java.nio.file.Path;
+
+/**
+ * The specification to fetch specific block from blob store
+ *
+ * @opensearch.internal
+ */
+public class BlobFetchRequest {
+
+    private final long position;
+
+    private final long length;
+
+    private final String blobName;
+
+    private final Path filePath;
+
+    private final Directory directory;
+
+    private final String fileName;
+
+    private BlobFetchRequest(Builder builder) {
+        this.position = builder.position;
+        this.length = builder.length;
+        this.blobName = builder.blobName;
+        this.fileName = builder.fileName;
+        this.filePath = builder.directory.getDirectory().resolve(fileName);
+        this.directory = builder.directory;
+    }
+
+    public long getPosition() {
+        return position;
+    }
+
+    public long getLength() {
+        return length;
+    }
+
+    public String getBlobName() {
+        return blobName;
+    }
+
+    public Path getFilePath() {
+        return filePath;
+    }
+
+    public Directory getDirectory() {
+        return directory;
+    }
+
+    public String getFileName() {
+        return fileName;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public String toString() {
+        return "BlobFetchRequest{"
+            + "position="
+            + position
+            + ", length="
+            + length
+            + ", blobName='"
+            + blobName
+            + '\''
+            + ", filePath="
+            + filePath
+            + ", directory="
+            + directory
+            + ", fileName='"
+            + fileName
+            + '\''
+            + '}';
+    }
+
+    /**
+     * Builder for BlobFetchRequest
+     */
+    public static final class Builder {
+        private long position;
+        private long length;
+        private String blobName;
+        private FSDirectory directory;
+        private String fileName;
+
+        private Builder() {}
+
+        public Builder position(long position) {
+            this.position = position;
+            return this;
+        }
+
+        public Builder length(long length) {
+            if (length <= 0) {
+                throw new IllegalArgumentException("Length for blob fetch request needs to be non-negative");
+            }
+            this.length = length;
+            return this;
+        }
+
+        public Builder blobName(String blobName) {
+            this.blobName = blobName;
+            return this;
+        }
+
+        public Builder directory(FSDirectory directory) {
+            this.directory = directory;
+            return this;
+        }
+
+        public Builder fileName(String fileName) {
+            this.fileName = fileName;
+            return this;
+        }
+
+        public BlobFetchRequest build() {
+            return new BlobFetchRequest(this);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/TransferManager.java b/server/src/main/java/org/opensearch/index/store/remote/utils/TransferManager.java
new file mode 100644
index 0000000000000..c9469283ee921
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/TransferManager.java
@@ -0,0 +1,178 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.index.store.remote.filecache.CachedIndexInput;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCachedIndexInput;
+
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * This acts as entry point to fetch {@link BlobFetchRequest} and return actual {@link IndexInput}. Utilizes the BlobContainer interface to
+ * read snapshot files located within a repository. This basically adapts BlobContainer snapshots files into IndexInput
+ *
+ * @opensearch.internal
+ */
+public class TransferManager {
+    private static final Logger logger = LogManager.getLogger(TransferManager.class);
+
+    private final BlobContainer blobContainer;
+    private final FileCache fileCache;
+
+    public TransferManager(final BlobContainer blobContainer, final FileCache fileCache) {
+        this.blobContainer = blobContainer;
+        this.fileCache = fileCache;
+    }
+
+    /**
+     * Given a blobFetchRequest, return it's corresponding IndexInput.
+     * @param blobFetchRequest to fetch
+     * @return future of IndexInput augmented with internal caching maintenance tasks
+     */
+    public IndexInput fetchBlob(BlobFetchRequest blobFetchRequest) throws IOException {
+        final Path key = blobFetchRequest.getFilePath();
+
+        final CachedIndexInput cacheEntry = fileCache.compute(key, (path, cachedIndexInput) -> {
+            if (cachedIndexInput == null || cachedIndexInput.isClosed()) {
+                // Doesn't exist or is closed, either way create a new one
+                return new DelayedCreationCachedIndexInput(fileCache, blobContainer, blobFetchRequest);
+            } else {
+                // already in the cache and ready to be used (open)
+                return cachedIndexInput;
+            }
+        });
+
+        // Cache entry was either retrieved from the cache or newly added, either
+        // way the reference count has been incremented by one. We can only
+        // decrement this reference _after_ creating the clone to be returned.
+        try {
+            return cacheEntry.getIndexInput().clone();
+        } finally {
+            fileCache.decRef(key);
+        }
+    }
+
+    private static FileCachedIndexInput createIndexInput(FileCache fileCache, BlobContainer blobContainer, BlobFetchRequest request) {
+        // We need to do a privileged action here in order to fetch from remote
+        // and write to the local file cache in case this is invoked as a side
+        // effect of a plugin (such as a scripted search) that doesn't have the
+        // necessary permissions.
+        return AccessController.doPrivileged((PrivilegedAction<FileCachedIndexInput>) () -> {
+            try {
+                if (Files.exists(request.getFilePath()) == false) {
+                    try (
+                        InputStream snapshotFileInputStream = blobContainer.readBlob(
+                            request.getBlobName(),
+                            request.getPosition(),
+                            request.getLength()
+                        );
+                        OutputStream fileOutputStream = Files.newOutputStream(request.getFilePath());
+                        OutputStream localFileOutputStream = new BufferedOutputStream(fileOutputStream)
+                    ) {
+                        snapshotFileInputStream.transferTo(localFileOutputStream);
+                    }
+                }
+                final IndexInput luceneIndexInput = request.getDirectory().openInput(request.getFileName(), IOContext.READ);
+                return new FileCachedIndexInput(fileCache, request.getFilePath(), luceneIndexInput);
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+        });
+    }
+
+    /**
+     * Implementation of CachedIndexInput the defers creation of the underlying
+     * IndexInput until the first invocation of {@link #getIndexInput()}. This
+     * class is thread safe, and concurrent calls to {@link #getIndexInput()} will
+     * result in blocking until the initial thread completes the creation of the
+     * IndexInput.
+     */
+    private static class DelayedCreationCachedIndexInput implements CachedIndexInput {
+        private final FileCache fileCache;
+        private final BlobContainer blobContainer;
+        private final BlobFetchRequest request;
+        private final CompletableFuture<IndexInput> result = new CompletableFuture<>();
+        private final AtomicBoolean isStarted = new AtomicBoolean(false);
+        private final AtomicBoolean isClosed = new AtomicBoolean(false);
+
+        private DelayedCreationCachedIndexInput(FileCache fileCache, BlobContainer blobContainer, BlobFetchRequest request) {
+            this.fileCache = fileCache;
+            this.blobContainer = blobContainer;
+            this.request = request;
+        }
+
+        @Override
+        public IndexInput getIndexInput() throws IOException {
+            if (isClosed.get()) {
+                throw new IllegalStateException("Already closed");
+            }
+            if (isStarted.getAndSet(true) == false) {
+                // We're the first one here, need to download the block
+                try {
+                    result.complete(createIndexInput(fileCache, blobContainer, request));
+                } catch (Exception e) {
+                    result.completeExceptionally(e);
+                    fileCache.remove(request.getFilePath());
+                }
+            }
+            try {
+                return result.join();
+            } catch (CompletionException e) {
+                if (e.getCause() instanceof UncheckedIOException) {
+                    throw ((UncheckedIOException) e.getCause()).getCause();
+                } else if (e.getCause() instanceof RuntimeException) {
+                    throw (RuntimeException) e.getCause();
+                }
+                throw e;
+            }
+        }
+
+        @Override
+        public long length() {
+            return request.getLength();
+        }
+
+        @Override
+        public boolean isClosed() {
+            return isClosed.get();
+        }
+
+        @Override
+        public void close() throws Exception {
+            if (isClosed.getAndSet(true) == false) {
+                result.whenComplete((indexInput, error) -> {
+                    if (indexInput != null) {
+                        try {
+                            indexInput.close();
+                        } catch (IOException e) {
+                            logger.warn("Error closing IndexInput", e);
+                        }
+                    }
+                });
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/CacheUsage.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/CacheUsage.java
new file mode 100644
index 0000000000000..1cb9242926046
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/CacheUsage.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+/**
+ * Usage metrics for {@link RefCountedCache}
+ *
+ * @opensearch.internal
+ */
+public class CacheUsage {
+    /**
+     * Cache usage of the system
+     */
+    private final long usage;
+
+    /**
+     * Cache usage by entries which are referenced
+     */
+    private final long activeUsage;
+
+    public CacheUsage(long usage, long activeUsage) {
+        this.usage = usage;
+        this.activeUsage = activeUsage;
+    }
+
+    public long usage() {
+        return usage;
+    }
+
+    public long activeUsage() {
+        return activeUsage;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/LRUCache.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/LRUCache.java
new file mode 100644
index 0000000000000..03d03711f914a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/LRUCache.java
@@ -0,0 +1,366 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+import org.opensearch.common.cache.RemovalListener;
+import org.opensearch.common.cache.RemovalNotification;
+import org.opensearch.common.cache.RemovalReason;
+import org.opensearch.common.cache.Weigher;
+import org.opensearch.index.store.remote.utils.cache.stats.CacheStats;
+import org.opensearch.index.store.remote.utils.cache.stats.DefaultStatsCounter;
+import org.opensearch.index.store.remote.utils.cache.stats.StatsCounter;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Objects;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiFunction;
+import java.util.function.Predicate;
+
+/**
+ * LRU implementation of {@link RefCountedCache}. As long as {@link Node#refCount} greater than 0 then node is not eligible for eviction.
+ * So this is best effort lazy cache to maintain capacity. <br>
+ * For more context why in-house cache implementation exist look at
+ * <a href="https://github.com/opensearch-project/OpenSearch/issues/4964#issuecomment-1421689586">this comment</a> and
+ * <a href="https://github.com/opensearch-project/OpenSearch/issues/6225">this ticket for future plans</a>
+ * <br>
+ * This cache implementation meets these requirements:
+ * <ul>
+ * <li>This cache has max capacity and this cache will best-effort maintain it's size to not exceed defined capacity</li>
+ * <li>Cache capacity is computed as the sum of all {@link Weigher#weightOf(Object)}</li>
+ * <li>Supports RemovalListener</li>
+ * <li>Cache maintains it's capacity using LRU Eviction while ignoring entries with {@link Node#refCount} greater than 0 from eviction</li>
+ * </ul>
+ * @see RefCountedCache
+ *
+ * @opensearch.internal
+ */
+class LRUCache<K, V> implements RefCountedCache<K, V> {
+    private final long capacity;
+
+    private final HashMap<K, Node<K, V>> data;
+
+    /** the LRU list */
+    private final LinkedHashMap<K, Node<K, V>> lru;
+
+    private final RemovalListener<K, V> listener;
+
+    private final Weigher<V> weigher;
+
+    private final StatsCounter<K> statsCounter;
+
+    private final ReentrantLock lock;
+
+    /**
+     * this tracks cache usage on the system (as long as cache entry is in the cache)
+     */
+    private long usage;
+
+    /**
+     * this tracks cache usage only by entries which are being referred ({@link Node#refCount > 0})
+     */
+    private long activeUsage;
+
+    static class Node<K, V> {
+        final K key;
+
+        V value;
+
+        long weight;
+
+        int refCount;
+
+        Node(K key, V value, long weight) {
+            this.key = key;
+            this.value = value;
+            this.weight = weight;
+            this.refCount = 0;
+        }
+
+        public boolean evictable() {
+            return (refCount == 0);
+        }
+    }
+
+    public LRUCache(long capacity, RemovalListener<K, V> listener, Weigher<V> weigher) {
+        this.capacity = capacity;
+        this.listener = listener;
+        this.weigher = weigher;
+        this.data = new HashMap<>();
+        this.lru = new LinkedHashMap<>();
+        this.lock = new ReentrantLock();
+        this.statsCounter = new DefaultStatsCounter<>();
+
+    }
+
+    @Override
+    public V get(K key) {
+        Objects.requireNonNull(key);
+        lock.lock();
+        try {
+            Node<K, V> node = data.get(key);
+            // miss
+            if (node == null) {
+                statsCounter.recordMisses(key, 1);
+                return null;
+            }
+            // hit
+            incRef(key);
+            statsCounter.recordHits(key, 1);
+            return node.value;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public V put(K key, V value) {
+        Objects.requireNonNull(key);
+        Objects.requireNonNull(value);
+
+        lock.lock();
+        try {
+            Node<K, V> node = data.get(key);
+            if (node != null) {
+                final V oldValue = node.value;
+                replaceNode(node, value);
+                return oldValue;
+            } else {
+                addNode(key, value);
+                return null;
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+        Objects.requireNonNull(key);
+        Objects.requireNonNull(remappingFunction);
+        lock.lock();
+        try {
+            final Node<K, V> node = data.get(key);
+            if (node == null) {
+                final V newValue = remappingFunction.apply(key, null);
+                if (newValue == null) {
+                    // Remapping function asked for removal, but nothing to remove
+                    return null;
+                } else {
+                    addNode(key, newValue);
+                    statsCounter.recordMisses(key, 1);
+                    return newValue;
+                }
+            } else {
+                final V newValue = remappingFunction.apply(key, node.value);
+                if (newValue == null) {
+                    removeNode(key);
+                    return null;
+                } else {
+                    statsCounter.recordHits(key, 1);
+                    replaceNode(node, newValue);
+                    return newValue;
+                }
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public void remove(K key) {
+        Objects.requireNonNull(key);
+        lock.lock();
+        try {
+            removeNode(key);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public void clear() {
+        lock.lock();
+        try {
+            usage = 0L;
+            activeUsage = 0L;
+            lru.clear();
+            for (Node<K, V> node : data.values()) {
+                data.remove(node.key);
+                statsCounter.recordRemoval(node.weight);
+                listener.onRemoval(new RemovalNotification<>(node.key, node.value, RemovalReason.EXPLICIT));
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public long size() {
+        return data.size();
+    }
+
+    @Override
+    public void incRef(K key) {
+        Objects.requireNonNull(key);
+        lock.lock();
+        try {
+            Node<K, V> node = data.get(key);
+            if (node != null) {
+                if (node.refCount == 0) {
+                    // if it was inactive, we should add the weight to active usage from now
+                    activeUsage += node.weight;
+                }
+
+                if (node.evictable()) {
+                    // since it become active, we should remove it from eviction list
+                    lru.remove(node.key);
+                }
+
+                node.refCount++;
+            }
+
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public void decRef(K key) {
+        Objects.requireNonNull(key);
+        lock.lock();
+        try {
+            Node<K, V> node = data.get(key);
+            if (node != null && node.refCount > 0) {
+                node.refCount--;
+
+                if (node.evictable()) {
+                    // if it becomes evictable, we should add it to eviction list
+                    lru.put(node.key, node);
+                }
+
+                if (node.refCount == 0) {
+                    // if it was active, we should remove its weight from active usage
+                    activeUsage -= node.weight;
+                }
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public long prune(Predicate<K> keyPredicate) {
+        long sum = 0L;
+        lock.lock();
+        try {
+            final Iterator<Node<K, V>> iterator = lru.values().iterator();
+            while (iterator.hasNext()) {
+                final Node<K, V> node = iterator.next();
+                if (keyPredicate != null && !keyPredicate.test(node.key)) {
+                    continue;
+                }
+                iterator.remove();
+                data.remove(node.key, node);
+                sum += node.weight;
+                statsCounter.recordRemoval(node.weight);
+                listener.onRemoval(new RemovalNotification<>(node.key, node.value, RemovalReason.EXPLICIT));
+            }
+            usage -= sum;
+        } finally {
+            lock.unlock();
+        }
+        return sum;
+    }
+
+    @Override
+    public CacheUsage usage() {
+        lock.lock();
+        try {
+            return new CacheUsage(usage, activeUsage);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    @Override
+    public CacheStats stats() {
+        lock.lock();
+        try {
+            return statsCounter.snapshot();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private void addNode(K key, V value) {
+        final long weight = weigher.weightOf(value);
+        Node<K, V> newNode = new Node<>(key, value, weight);
+        data.put(key, newNode);
+        usage += weight;
+        incRef(key);
+        evict();
+    }
+
+    private void replaceNode(Node<K, V> node, V newValue) {
+        if (node.value != newValue) { // replace if new value is not the same instance as existing value
+            final V oldValue = node.value;
+            final long oldWeight = node.weight;
+            final long newWeight = weigher.weightOf(newValue);
+            // update the value and weight
+            node.value = newValue;
+            node.weight = newWeight;
+            // update usage
+            final long weightDiff = newWeight - oldWeight;
+            if (node.refCount > 0) {
+                activeUsage += weightDiff;
+            }
+            usage += weightDiff;
+            statsCounter.recordReplacement();
+            listener.onRemoval(new RemovalNotification<>(node.key, oldValue, RemovalReason.REPLACED));
+        }
+        incRef(node.key);
+        evict();
+    }
+
+    private void removeNode(K key) {
+        Node<K, V> node = data.remove(key);
+        if (node != null) {
+            if (node.refCount > 0) {
+                activeUsage -= node.weight;
+            }
+            usage -= node.weight;
+            if (node.evictable()) {
+                lru.remove(node.key);
+            }
+            statsCounter.recordRemoval(node.weight);
+            listener.onRemoval(new RemovalNotification<>(node.key, node.value, RemovalReason.EXPLICIT));
+        }
+    }
+
+    private boolean hasOverflowed() {
+        return usage >= capacity;
+    }
+
+    private void evict() {
+        // Attempts to evict entries from the cache if it exceeds the maximum
+        // capacity.
+        final Iterator<Node<K, V>> iterator = lru.values().iterator();
+        while (hasOverflowed() && iterator.hasNext()) {
+            final Node<K, V> node = iterator.next();
+            iterator.remove();
+            // Notify the listener only if the entry was evicted
+            data.remove(node.key, node);
+            usage -= node.weight;
+            statsCounter.recordEviction(node.weight);
+            listener.onRemoval(new RemovalNotification<>(node.key, node.value, RemovalReason.CAPACITY));
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/RefCountedCache.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/RefCountedCache.java
new file mode 100644
index 0000000000000..e6b5a5f945d83
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/RefCountedCache.java
@@ -0,0 +1,113 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+import org.opensearch.index.store.remote.utils.cache.stats.CacheStats;
+
+import java.util.function.BiFunction;
+import java.util.function.Predicate;
+
+/**
+ * Custom Cache which support typical cache operations (put, get, ...) and it support reference counting per individual key which might
+ * change eviction behavior
+ * @param <K> type of the key
+ * @param <V> type of the value
+ *
+ * @opensearch.internal
+ */
+public interface RefCountedCache<K, V> {
+
+    /**
+     * Returns the value associated with {@code key} in this cache, or {@code null} if there is no
+     * cached value for {@code key}. Retrieving an item automatically increases its reference
+     * count.
+     */
+    V get(K key);
+
+    /**
+     * Associates {@code value} with {@code key} in this cache. If the cache previously contained a
+     * value associated with {@code key}, the old value is replaced by {@code value}.
+     */
+    V put(K key, V value);
+
+    /**
+     * If the specified key is already associated with a value, attempts to update its value using the given mapping
+     * function and enters the new value. If the mapping function returns null the item is removed from the
+     * cache, regardless of its reference count. If the mapping function returns non-null the value is updated.
+     * The new entry will have the reference count of the previous entry plus one, as this method automatically
+     * increases the reference count by one when it returns the newly mapped value.
+     * <p>
+     * If the specified key is NOT already associated with a value, then the value of the remapping function
+     * will be associated with the given key, and its reference count will be set to one. If the remapping function
+     * returns null then nothing is done.
+     * <p>
+     * The remappingFunction method for a given key will be invoked at most once.
+     */
+    V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction);
+
+    /**
+     * Discards any cached value for key {@code key}, regardless of reference count.
+     */
+    void remove(K key);
+
+    /**
+     * Discards all entries in the cache, regardless of reference count.
+     */
+    void clear();
+
+    /**
+     * Returns the approximate number of entries in this cache.
+     */
+    long size();
+
+    /**
+     * increment references count for key {@code key}.
+     */
+    void incRef(K key);
+
+    /**
+     * decrement references count for key {@code key}.
+     */
+    void decRef(K key);
+
+    /**
+     * Removes all cache entries with a reference count of zero, regardless of current capacity.
+     *
+     * @return The total weight of all removed entries.
+     */
+    default long prune() {
+        return prune(key -> true);
+    }
+
+    /**
+     * Removes the cache entries which match the predicate criteria for the key
+     * and have a reference count of zero, regardless of current capacity.
+     *
+     * @return The total weight of all removed entries.
+     */
+    long prune(Predicate<K> keyPredicate);
+
+    /**
+     * Returns the weighted usage of this cache.
+     *
+     * @return the combined weight of the values in this cache
+     */
+    CacheUsage usage();
+
+    /**
+     * Returns a current snapshot of this cache's cumulative statistics. All statistics are
+     * initialized to zero, and are monotonically increasing over the lifetime of the cache.
+     * <p>
+     * Due to the performance penalty of maintaining statistics, some implementations may not record
+     * the usage history immediately or at all.
+     *
+     * @return the current snapshot of the statistics of this cache
+     */
+    CacheStats stats();
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/SegmentedCache.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/SegmentedCache.java
new file mode 100644
index 0000000000000..d3eb03df37e1b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/SegmentedCache.java
@@ -0,0 +1,325 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+import org.opensearch.common.cache.RemovalListener;
+import org.opensearch.common.cache.RemovalNotification;
+import org.opensearch.common.cache.Weigher;
+import org.opensearch.index.store.remote.utils.cache.stats.CacheStats;
+
+import java.util.Objects;
+import java.util.function.BiFunction;
+import java.util.function.Predicate;
+
+/**
+ * Segmented {@link LRUCache} to offer concurrent access with less contention.
+ * @param <K> type of the key
+ * @param <V> type of th value
+ *
+ * @opensearch.internal
+ */
+public class SegmentedCache<K, V> implements RefCountedCache<K, V> {
+
+    private static final int HASH_BITS = 0x7fffffff;
+
+    private static final int ceilingNextPowerOfTwo(int x) {
+        // From Hacker's Delight, Chapter 3, Harry S. Warren Jr.
+        return 1 << (Integer.SIZE - Integer.numberOfLeadingZeros(x - 1));
+    }
+
+    private final long capacity;
+
+    private final long perSegmentCapacity;
+    /**
+     * The array of bins. Size is always a power of two.
+     */
+    private final RefCountedCache<K, V>[] table;
+
+    /**
+     * Mask value for indexing into segments.
+     */
+    private final int segmentMask;
+
+    private final Weigher<V> weigher;
+
+    public SegmentedCache(Builder<K, V> builder) {
+        this.capacity = builder.capacity;
+        final int segments = ceilingNextPowerOfTwo(builder.concurrencyLevel);
+        this.segmentMask = segments - 1;
+        this.table = newSegmentArray(segments);
+        this.perSegmentCapacity = (capacity + (segments - 1)) / segments;
+        this.weigher = builder.weigher;
+        for (int i = 0; i < table.length; i++) {
+            table[i] = new LRUCache<>(perSegmentCapacity, builder.listener, builder.weigher);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    final RefCountedCache<K, V>[] newSegmentArray(int size) {
+        return new RefCountedCache[size];
+    }
+
+    RefCountedCache<K, V> segmentFor(K key) {
+        int h = key.hashCode();
+        // Based on this answer https://stackoverflow.com/a/12996028
+        h = ((h >>> 16) ^ h) * 0x45d9f3b;
+        h = ((h >>> 16) ^ h) * 0x45d9f3b;
+        h = (h >>> 16) ^ h;
+        return table[h & HASH_BITS & segmentMask];
+    }
+
+    public long capacity() {
+        return capacity;
+    }
+
+    @Override
+    public V get(K key) {
+        if (key == null) throw new NullPointerException();
+        return segmentFor(key).get(key);
+    }
+
+    @Override
+    public V put(K key, V value) {
+        if (key == null || value == null) throw new NullPointerException();
+        return segmentFor(key).put(key, value);
+    }
+
+    @Override
+    public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+        if (key == null || remappingFunction == null) throw new NullPointerException();
+        return segmentFor(key).compute(key, remappingFunction);
+    }
+
+    @Override
+    public void remove(K key) {
+        if (key == null) throw new NullPointerException();
+        segmentFor(key).remove(key);
+    }
+
+    @Override
+    public void clear() {
+        for (RefCountedCache<K, V> cache : table) {
+            cache.clear();
+        }
+    }
+
+    @Override
+    public long size() {
+        long size = 0;
+        for (RefCountedCache<K, V> cache : table) {
+            size += cache.size();
+        }
+        return size;
+    }
+
+    @Override
+    public void incRef(K key) {
+        if (key == null) throw new NullPointerException();
+        segmentFor(key).incRef(key);
+    }
+
+    @Override
+    public void decRef(K key) {
+        if (key == null) throw new NullPointerException();
+        segmentFor(key).decRef(key);
+    }
+
+    @Override
+    public long prune() {
+        long sum = 0L;
+        for (RefCountedCache<K, V> cache : table) {
+            sum += cache.prune();
+        }
+        return sum;
+    }
+
+    @Override
+    public long prune(Predicate<K> keyPredicate) {
+        long sum = 0L;
+        for (RefCountedCache<K, V> cache : table) {
+            sum += cache.prune(keyPredicate);
+        }
+        return sum;
+    }
+
+    @Override
+    public CacheUsage usage() {
+        long usage = 0L;
+        long activeUsage = 0L;
+        for (RefCountedCache<K, V> cache : table) {
+            CacheUsage c = cache.usage();
+            usage += c.usage();
+            activeUsage += c.activeUsage();
+        }
+        return new CacheUsage(usage, activeUsage);
+    }
+
+    @Override
+    public CacheStats stats() {
+        long hitCount = 0L;
+        long missCount = 0L;
+        long removeCount = 0L;
+        long removeWeight = 0L;
+        long replaceCount = 0L;
+        long evictionCount = 0L;
+        long evictionWeight = 0L;
+
+        for (RefCountedCache<K, V> cache : table) {
+            CacheStats c = cache.stats();
+            hitCount += c.hitCount();
+            missCount += c.missCount();
+            removeCount += c.removeCount();
+            removeWeight += c.removeWeight();
+            replaceCount += c.replaceCount();
+            evictionCount += c.evictionCount();
+            evictionWeight += c.evictionWeight();
+        }
+        return new CacheStats(hitCount, missCount, removeCount, removeWeight, replaceCount, evictionCount, evictionWeight);
+    }
+
+    enum SingletonWeigher implements Weigher<Object> {
+        INSTANCE;
+
+        @Override
+        public long weightOf(Object value) {
+            return 1;
+        }
+    }
+
+    /**
+     * A listener that ignores all notifications.
+     */
+    enum DiscardingListener implements RemovalListener<Object, Object> {
+        INSTANCE;
+
+        @Override
+        public void onRemoval(RemovalNotification<Object, Object> notification) {
+
+        }
+    }
+
+    /**
+     * @return the capacity per internal segment
+     */
+    public long getPerSegmentCapacity() {
+        return perSegmentCapacity;
+    }
+
+    /**
+     * @return the weigher used for IndexInput
+     */
+    public Weigher<V> getWeigher() {
+        return weigher;
+    }
+
+    /**
+     * A builder that creates {@link SegmentedCache} instances. It
+     * provides a flexible approach for constructing customized instances with
+     * a named parameter syntax.
+     */
+    public static final class Builder<K, V> {
+
+        static final int DEFAULT_CONCURRENCY_LEVEL = Runtime.getRuntime().availableProcessors();
+
+        RemovalListener<K, V> listener;
+        Weigher<V> weigher;
+
+        int concurrencyLevel;
+
+        long capacity;
+
+        @SuppressWarnings("unchecked")
+        Builder() {
+            capacity = -1;
+            weigher = (Weigher<V>) SingletonWeigher.INSTANCE;
+            concurrencyLevel = DEFAULT_CONCURRENCY_LEVEL;
+            listener = (RemovalListener<K, V>) DiscardingListener.INSTANCE;
+        }
+
+        /**
+         * Specifies the maximum weighted capacity to coerce the map to and may
+         * exceed it temporarily.
+         *
+         * @param capacity the weighted threshold to bound the map by
+         * @throws IllegalArgumentException if the maximumWeightedCapacity is
+         *                                  negative
+         */
+        public Builder<K, V> capacity(long capacity) {
+            checkArgument(capacity >= 0, "capacity has to be greater or equal to 0");
+            this.capacity = capacity;
+            return this;
+        }
+
+        /**
+         * Specifies the estimated number of concurrently updating threads. The
+         * implementation performs internal sizing to try to accommodate this many
+         * threads (default Runtime.getRuntime().availableProcessors()).
+         *
+         * @param concurrencyLevel the estimated number of concurrently updating
+         *                         threads
+         * @throws IllegalArgumentException if the concurrencyLevel is less than or
+         *                                  equal to zero
+         */
+        public Builder<K, V> concurrencyLevel(int concurrencyLevel) {
+            checkArgument(concurrencyLevel > 0, "concurrencyLevel has to be greater than 0");
+            this.concurrencyLevel = concurrencyLevel;
+            return this;
+        }
+
+        /**
+         * Specifies an optional listener that is registered for notification when
+         * an entry is removed.
+         *
+         * @param listener the object to forward removed entries to
+         * @throws NullPointerException if the listener is null
+         */
+        public Builder<K, V> listener(RemovalListener<K, V> listener) {
+            Objects.requireNonNull(listener);
+            this.listener = listener;
+            return this;
+        }
+
+        /**
+         * Specifies an algorithm to determine how many the units of capacity a
+         * value consumes. The default algorithm bounds the map by the number of
+         * key-value pairs by giving each entry a weight of 1.
+         *
+         * @param weigher the algorithm to determine a value's weight
+         * @throws NullPointerException if the weigher is null
+         */
+        public Builder<K, V> weigher(Weigher<V> weigher) {
+            Objects.requireNonNull(weigher);
+            this.weigher = weigher;
+            return this;
+        }
+
+        /**
+         * Ensures that the argument expression is true.
+         */
+        private static void checkArgument(boolean expression, String message) {
+            if (!expression) {
+                throw new IllegalArgumentException(message);
+            }
+        }
+
+        /**
+         * Creates a new {@link SegmentedCache} instance.
+         *
+         * @throws IllegalStateException if the maximum weighted capacity was
+         *                               not set
+         */
+        public SegmentedCache<K, V> build() {
+            return new SegmentedCache<>(this);
+        }
+    }
+
+    public static <K, V> Builder<K, V> builder() {
+        return new Builder<>();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/package-info.java
new file mode 100644
index 0000000000000..95025a5c40690
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/package-info.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Reference counted cache which is a cache which takes into consideration reference count per cache entry and it's eviction policy
+ * depends on current reference count. <br>
+ * For more context why in-house cache implementation exist look at
+ * <a href="https://github.com/opensearch-project/OpenSearch/issues/4964#issuecomment-1421689586">this comment</a> and
+ * <a href="https://github.com/opensearch-project/OpenSearch/issues/6225">this ticket for future plans</a>
+ */
+package org.opensearch.index.store.remote.utils.cache;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/CacheStats.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/CacheStats.java
new file mode 100644
index 0000000000000..f0a7154effb1d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/CacheStats.java
@@ -0,0 +1,225 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache.stats;
+
+import org.opensearch.index.store.remote.utils.cache.RefCountedCache;
+
+import java.util.Objects;
+
+/**
+ * Statistics about the performance of a {@link RefCountedCache}.
+ *
+ * @opensearch.internal
+ */
+public final class CacheStats {
+    private final long hitCount;
+    private final long missCount;
+    private final long removeCount;
+    private final long removeWeight;
+    private final long replaceCount;
+    private final long evictionCount;
+    private final long evictionWeight;
+
+    /**
+     * Constructs a new {@code CacheStats} instance.
+     * <p>
+     * Many parameters of the same type in a row is a bad thing, but this class is not constructed
+     * by end users and is too fine-grained for a builder.
+     *
+     * @param hitCount       the number of cache hits
+     * @param missCount      the number of cache misses*
+     * @param removeCount    the number of entries removed from the cache
+     * @param removeWeight   the sum of weights of entries removed from the cache
+     * @param replaceCount   the number of entries replaced explicitly from the cache
+     * @param evictionCount  the number of entries evicted from the cache
+     * @param evictionWeight the sum of weights of entries evicted from the cache
+     */
+    public CacheStats(
+        long hitCount,
+        long missCount,
+        long removeCount,
+        long removeWeight,
+        long replaceCount,
+        long evictionCount,
+        long evictionWeight
+    ) {
+        if ((hitCount < 0)
+            || (missCount < 0)
+            || (removeCount < 0)
+            || (removeWeight < 0)
+            || (replaceCount < 0)
+            || (evictionCount < 0)
+            || (evictionWeight < 0)) {
+            throw new IllegalArgumentException();
+        }
+        this.hitCount = hitCount;
+        this.missCount = missCount;
+        this.removeCount = removeCount;
+        this.removeWeight = removeWeight;
+        this.replaceCount = replaceCount;
+        this.evictionCount = evictionCount;
+        this.evictionWeight = evictionWeight;
+    }
+
+    /**
+     * Returns the number of times {@link RefCountedCache} lookup methods have returned either a cached or
+     * uncached value. This is defined as {@code hitCount + missCount}.
+     *
+     * @return the {@code hitCount + missCount}
+     */
+    public long requestCount() {
+        return hitCount + missCount;
+    }
+
+    /**
+     * Returns the number of times {@link RefCountedCache} lookup methods have returned a cached value.
+     *
+     * @return the number of times {@link RefCountedCache} lookup methods have returned a cached value
+     */
+    public long hitCount() {
+        return hitCount;
+    }
+
+    /**
+     * Returns the ratio of cache requests which were hits. This is defined as
+     * {@code hitCount / requestCount}, or {@code 1.0} when {@code requestCount == 0}. Note that
+     * {@code hitRate + missRate =~ 1.0}.
+     *
+     * @return the ratio of cache requests which were hits
+     */
+    public double hitRate() {
+        long requestCount = requestCount();
+        return (requestCount == 0) ? 1.0 : (double) hitCount / requestCount;
+    }
+
+    /**
+     * Returns the number of times {@link RefCountedCache} lookup methods have returned an uncached (newly
+     * loaded) value, or null. Multiple concurrent calls to {@link RefCountedCache} lookup methods on an absent
+     * value can result in multiple misses, all returning the results of a single cache load
+     * operation.
+     *
+     * @return the number of times {@link RefCountedCache} lookup methods have returned an uncached (newly
+     * loaded) value, or null
+     */
+    public long missCount() {
+        return missCount;
+    }
+
+    /**
+     * Returns the ratio of cache requests which were misses. This is defined as
+     * {@code missCount / requestCount}, or {@code 0.0} when {@code requestCount == 0}.
+     * Note that {@code hitRate + missRate =~ 1.0}. Cache misses include all requests which
+     * weren't cache hits, including requests which resulted in either successful or failed loading
+     * attempts, and requests which waited for other threads to finish loading. It is thus the case
+     * that {@code missCount &gt;= loadSuccessCount + loadFailureCount}. Multiple
+     * concurrent misses for the same key will result in a single load operation.
+     *
+     * @return the ratio of cache requests which were misses
+     */
+    public double missRate() {
+        long requestCount = requestCount();
+        return (requestCount == 0) ? 0.0 : (double) missCount / requestCount;
+    }
+
+    /**
+     * Returns the number of times an entry has been removed explicitly.
+     *
+     * @return the number of times an entry has been removed
+     */
+    public long removeCount() {
+        return removeCount;
+    }
+
+    /**
+     * Returns the sum of weights of explicitly removed entries.
+     *
+     * @return the sum of weights of explicitly removed entries
+     */
+    public long removeWeight() {
+        return removeWeight;
+    }
+
+    /**
+     * Returns the number of times an entry has been replaced.
+     *
+     * @return the number of times an entry has been replaced
+     */
+    public long replaceCount() {
+        return replaceCount;
+    }
+
+    /**
+     * Returns the number of times an entry has been evicted. This count does not include manual
+     * {@linkplain RefCountedCache#remove removals}.
+     *
+     * @return the number of times an entry has been evicted
+     */
+    public long evictionCount() {
+        return evictionCount;
+    }
+
+    /**
+     * Returns the sum of weights of evicted entries. This total does not include manual
+     * {@linkplain RefCountedCache#remove removals}.
+     *
+     * @return the sum of weights of evicted entities
+     */
+    public long evictionWeight() {
+        return evictionWeight;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(hitCount, missCount, removeCount, removeWeight, replaceCount, evictionCount, evictionWeight);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        } else if (!(o instanceof CacheStats)) {
+            return false;
+        }
+        CacheStats other = (CacheStats) o;
+        return hitCount == other.hitCount
+            && missCount == other.missCount
+            && removeCount == other.removeCount
+            && removeWeight == other.removeWeight
+            && replaceCount == other.replaceCount
+            && evictionCount == other.evictionCount
+            && evictionWeight == other.evictionWeight;
+    }
+
+    @Override
+    public String toString() {
+        return getClass().getSimpleName()
+            + '{'
+            + "hitCount="
+            + hitCount
+            + ", "
+            + "missCount="
+            + missCount
+            + ", "
+            + "removeCount="
+            + removeCount
+            + ", "
+            + "removeWeight="
+            + removeWeight
+            + ", "
+            + "replaceCount="
+            + replaceCount
+            + ", "
+            + "evictionCount="
+            + evictionCount
+            + ", "
+            + "evictionWeight="
+            + evictionWeight
+            + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/DefaultStatsCounter.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/DefaultStatsCounter.java
new file mode 100644
index 0000000000000..60fe5223ef37e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/DefaultStatsCounter.java
@@ -0,0 +1,71 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache.stats;
+
+/**
+ * A non thread-safe {@link StatsCounter} implementation.
+ *
+ * @opensearch.internal
+ */
+public class DefaultStatsCounter<K> implements StatsCounter<K> {
+    private long hitCount;
+    private long missCount;
+    private long removeCount;
+    private long removeWeight;
+    private long replaceCount;
+    private long evictionCount;
+    private long evictionWeight;
+
+    public DefaultStatsCounter() {
+        this.hitCount = 0L;
+        this.missCount = 0L;
+        this.removeCount = 0L;
+        this.removeWeight = 0L;
+        this.replaceCount = 0L;
+        this.evictionCount = 0L;
+        this.evictionWeight = 0L;
+    }
+
+    @Override
+    public void recordHits(K key, int count) {
+        hitCount += count;
+    }
+
+    @Override
+    public void recordMisses(K key, int count) {
+        missCount += count;
+    }
+
+    @Override
+    public void recordRemoval(long weight) {
+        removeCount++;
+        removeWeight += weight;
+    }
+
+    @Override
+    public void recordReplacement() {
+        replaceCount++;
+    }
+
+    @Override
+    public void recordEviction(long weight) {
+        evictionCount++;
+        evictionWeight += weight;
+    }
+
+    @Override
+    public CacheStats snapshot() {
+        return new CacheStats(hitCount, missCount, removeCount, removeWeight, replaceCount, evictionCount, evictionWeight);
+    }
+
+    @Override
+    public String toString() {
+        return snapshot().toString();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/StatsCounter.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/StatsCounter.java
new file mode 100644
index 0000000000000..b096bb8d652ae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/StatsCounter.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache.stats;
+
+import org.opensearch.index.store.remote.utils.cache.RefCountedCache;
+
+import java.util.function.BiFunction;
+
+/**
+ * Accumulates statistics during the operation of a {@link RefCountedCache} for presentation by
+ * {@link RefCountedCache#stats}. This is solely intended for consumption by {@code Cache} implementors.
+ *
+ * @opensearch.internal
+ */
+public interface StatsCounter<K> {
+
+    /**
+     * Records cache hits. This should be called when a cache request returns a cached value.
+     *
+     * @param count the number of hits to record
+     */
+    void recordHits(K key, int count);
+
+    /**
+     * Records cache misses. This should be called when a cache request returns a value that was not
+     * found in the cache. This method should be called by the loading thread, as well as by threads
+     * blocking on the load. Multiple concurrent calls to {@link RefCountedCache} lookup methods with the same
+     * key on an absent value should result in a single call to either {@code recordLoadSuccess} or
+     * {@code recordLoadFailure} and multiple calls to this method, despite all being served by the
+     * results of a single load operation.
+     *
+     * @param count the number of misses to record
+     */
+    void recordMisses(K key, int count);
+
+    /**
+     * Records the explicit removal of an entry from the cache. This should only been called when an entry is
+     * removed as a result of manual
+     * {@link RefCountedCache#remove(Object)}
+     * {@link RefCountedCache#compute(Object, BiFunction)}
+     *
+     * @param weight the weight of the removed entry
+     */
+    void recordRemoval(long weight);
+
+    /**
+     * Records the replacement of an entry from the cache. This should only been called when an entry is
+     * replaced as a result of manual
+     * {@link RefCountedCache#put(Object, Object)}
+     * {@link RefCountedCache#compute(Object, BiFunction)}
+     */
+    void recordReplacement();
+
+    /**
+     * Records the eviction of an entry from the cache. This should only been called when an entry is
+     * evicted due to the cache's eviction strategy, and not as a result of manual
+     * {@link RefCountedCache#remove(Object)}  removals}.
+     *
+     * @param weight the weight of the evicted entry
+     */
+    void recordEviction(long weight);
+
+    /**
+     * Returns a snapshot of this counter's values. Note that this may be an inconsistent view, as it
+     * may be interleaved with update operations.
+     *
+     * @return a snapshot of this counter's values
+     */
+
+    CacheStats snapshot();
+}
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/package-info.java
new file mode 100644
index 0000000000000..9710ce4c59e81
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/cache/stats/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Cache stats for reference counted cache
+ */
+package org.opensearch.index.store.remote.utils.cache.stats;
diff --git a/server/src/main/java/org/opensearch/index/store/remote/utils/package-info.java b/server/src/main/java/org/opensearch/index/store/remote/utils/package-info.java
new file mode 100644
index 0000000000000..2b59166fed313
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/store/remote/utils/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Package containing utils used in remote store
+ */
+package org.opensearch.index.store.remote.utils;
diff --git a/server/src/main/java/org/opensearch/index/termvectors/TermVectorsService.java b/server/src/main/java/org/opensearch/index/termvectors/TermVectorsService.java
index 3467a86c86c86..7b7da6531aff3 100644
--- a/server/src/main/java/org/opensearch/index/termvectors/TermVectorsService.java
+++ b/server/src/main/java/org/opensearch/index/termvectors/TermVectorsService.java
@@ -39,6 +39,7 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.MultiTerms;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermVectors;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.memory.MemoryIndex;
 import org.opensearch.OpenSearchException;
@@ -46,13 +47,13 @@
 import org.opensearch.action.termvectors.TermVectorsRequest;
 import org.opensearch.action.termvectors.TermVectorsResponse;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndVersion;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.mapper.DocumentMapperForType;
@@ -83,6 +84,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.LongSupplier;
 
+/**
+ * Service for Term Vectors
+ *
+ * @opensearch.internal
+ */
 public class TermVectorsService {
 
     private TermVectorsService() {}
@@ -122,7 +128,8 @@ static TermVectorsResponse getTermVectors(IndexShard indexShard, TermVectorsRequ
             /* or from an existing document */
             else if (docIdAndVersion != null) {
                 // fields with stored term vectors
-                termVectorsByField = docIdAndVersion.reader.getTermVectors(docIdAndVersion.docId);
+                TermVectors termVectors = docIdAndVersion.reader.termVectors();
+                termVectorsByField = termVectors.get(docIdAndVersion.docId);
                 Set<String> selectedFields = request.selectedFields();
                 // generate tvs for fields where analyzer is overridden
                 if (selectedFields == null && request.perFieldAnalyzer() != null) {
@@ -317,7 +324,8 @@ private static Fields generateTermVectors(
             }
         }
         /* and read vectors from it */
-        return index.createSearcher().getIndexReader().getTermVectors(0);
+        TermVectors termVectors = index.createSearcher().getIndexReader().termVectors();
+        return termVectors.get(0);
     }
 
     private static Fields generateTermVectorsFromDoc(IndexShard indexShard, TermVectorsRequest request) throws IOException {
@@ -385,13 +393,13 @@ private static ParsedDocument parseDocument(
         IndexShard indexShard,
         String index,
         BytesReference doc,
-        XContentType xContentType,
+        MediaType mediaType,
         String routing
     ) {
         MapperService mapperService = indexShard.mapperService();
         DocumentMapperForType docMapper = mapperService.documentMapperWithAutoCreate();
         ParsedDocument parsedDocument = docMapper.getDocumentMapper()
-            .parse(new SourceToParse(index, "_id_for_tv_api", doc, xContentType, routing));
+            .parse(new SourceToParse(index, "_id_for_tv_api", doc, mediaType, routing));
         if (docMapper.getMapping() != null) {
             parsedDocument.addDynamicMappingsUpdate(docMapper.getMapping());
         }
@@ -418,7 +426,11 @@ private static Fields mergeFields(Fields fields1, Fields fields2) throws IOExcep
         return parallelFields;
     }
 
-    // Poached from Lucene ParallelLeafReader
+    /**
+     * Poached from Lucene ParallelLeafReader
+     *
+     * @opensearch.internal
+     */
     private static final class ParallelFields extends Fields {
         final Map<String, Terms> fields = new TreeMap<>();
 
diff --git a/server/src/main/java/org/opensearch/index/termvectors/package-info.java b/server/src/main/java/org/opensearch/index/termvectors/package-info.java
new file mode 100644
index 0000000000000..9c5ab1da547f6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/termvectors/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** TermVectorsService package */
+package org.opensearch.index.termvectors;
diff --git a/server/src/main/java/org/opensearch/index/translog/BaseTranslogReader.java b/server/src/main/java/org/opensearch/index/translog/BaseTranslogReader.java
index 138ad9a221096..ea817c4b0932a 100644
--- a/server/src/main/java/org/opensearch/index/translog/BaseTranslogReader.java
+++ b/server/src/main/java/org/opensearch/index/translog/BaseTranslogReader.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.translog;
 
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.index.seqno.SequenceNumbers;
 
 import java.io.IOException;
@@ -43,6 +43,8 @@
 
 /**
  * A base class for all classes that allows reading ops from translog files
+ *
+ * @opensearch.internal
  */
 public abstract class BaseTranslogReader implements Comparable<BaseTranslogReader> {
 
diff --git a/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamInput.java b/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamInput.java
index e93ba670ffd45..8c9ccc3b487df 100644
--- a/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamInput.java
+++ b/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamInput.java
@@ -33,9 +33,10 @@
 package org.opensearch.index.translog;
 
 import org.apache.lucene.store.BufferedChecksum;
-import org.opensearch.common.io.stream.FilterStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.FilterStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
+import java.io.EOFException;
 import java.io.IOException;
 import java.util.zip.CRC32;
 import java.util.zip.Checksum;
@@ -43,6 +44,8 @@
 /**
  * Similar to Lucene's BufferedChecksumIndexInput, however this wraps a
  * {@link StreamInput} so anything read will update the checksum
+ *
+ * @opensearch.internal
  */
 public final class BufferedChecksumStreamInput extends FilterStreamInput {
     private static final int SKIP_BUFFER_SIZE = 1024;
@@ -115,7 +118,11 @@ public void reset() throws IOException {
 
     @Override
     public int read() throws IOException {
-        return readByte() & 0xFF;
+        try {
+            return readByte() & 0xFF;
+        } catch (EOFException e) {
+            return -1;
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamOutput.java b/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamOutput.java
index 9d2375df7a9d7..eaf9ac0893f1b 100644
--- a/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamOutput.java
+++ b/server/src/main/java/org/opensearch/index/translog/BufferedChecksumStreamOutput.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.translog;
 
 import org.apache.lucene.store.BufferedChecksum;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.zip.CRC32;
@@ -42,6 +42,8 @@
 /**
  * Similar to Lucene's BufferedChecksumIndexOutput, however this wraps a
  * {@link StreamOutput} so anything written will update the checksum
+ *
+ * @opensearch.internal
  */
 public final class BufferedChecksumStreamOutput extends StreamOutput {
     private final StreamOutput out;
diff --git a/server/src/main/java/org/opensearch/index/translog/ChannelFactory.java b/server/src/main/java/org/opensearch/index/translog/ChannelFactory.java
index 46eef80c95ff9..f86b9dea0a5f7 100644
--- a/server/src/main/java/org/opensearch/index/translog/ChannelFactory.java
+++ b/server/src/main/java/org/opensearch/index/translog/ChannelFactory.java
@@ -39,6 +39,8 @@
 
 /**
  * only for testing until we have a disk-full FileSystem
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface ChannelFactory {
diff --git a/server/src/main/java/org/opensearch/index/translog/Checkpoint.java b/server/src/main/java/org/opensearch/index/translog/Checkpoint.java
index 0cff884cabfaa..a9f905f52bc3a 100644
--- a/server/src/main/java/org/opensearch/index/translog/Checkpoint.java
+++ b/server/src/main/java/org/opensearch/index/translog/Checkpoint.java
@@ -54,7 +54,12 @@
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
 
-final class Checkpoint {
+/**
+ * A checkpoint for OpenSearch operations
+ *
+ * @opensearch.internal
+ */
+final public class Checkpoint {
 
     final long offset;
     final int numOps;
@@ -218,15 +223,17 @@ public static void write(ChannelFactory factory, Path checkpointFile, Checkpoint
         }
     }
 
-    public static void write(FileChannel fileChannel, Path checkpointFile, Checkpoint checkpoint) throws IOException {
+    public static void write(FileChannel fileChannel, Path checkpointFile, Checkpoint checkpoint, boolean fsync) throws IOException {
         byte[] bytes = createCheckpointBytes(checkpointFile, checkpoint);
         Channels.writeToChannel(bytes, fileChannel, 0);
-        // no need to force metadata, file size stays the same and we did the full fsync
-        // when we first created the file, so the directory entry doesn't change as well
-        fileChannel.force(false);
+        if (fsync == true) {
+            // no need to force metadata, file size stays the same and we did the full fsync
+            // when we first created the file, so the directory entry doesn't change as well
+            fileChannel.force(false);
+        }
     }
 
-    private static byte[] createCheckpointBytes(Path checkpointFile, Checkpoint checkpoint) throws IOException {
+    public static byte[] createCheckpointBytes(Path checkpointFile, Checkpoint checkpoint) throws IOException {
         final ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream(V4_FILE_SIZE) {
             @Override
             public synchronized byte[] toByteArray() {
@@ -257,6 +264,14 @@ public synchronized byte[] toByteArray() {
         return byteOutputStream.toByteArray();
     }
 
+    public long getMinTranslogGeneration() {
+        return minTranslogGeneration;
+    }
+
+    public long getGeneration() {
+        return generation;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
diff --git a/server/src/main/java/org/opensearch/index/translog/DefaultTranslogDeletionPolicy.java b/server/src/main/java/org/opensearch/index/translog/DefaultTranslogDeletionPolicy.java
index 1346a16910d58..efc762ef00d52 100644
--- a/server/src/main/java/org/opensearch/index/translog/DefaultTranslogDeletionPolicy.java
+++ b/server/src/main/java/org/opensearch/index/translog/DefaultTranslogDeletionPolicy.java
@@ -16,6 +16,8 @@
  * via the {@link org.opensearch.plugins.EnginePlugin#getCustomTranslogDeletionPolicyFactory()}.
  *
  * The default policy uses total number, size in bytes and maximum age for files.
+ *
+ * @opensearch.internal
  */
 
 public class DefaultTranslogDeletionPolicy extends TranslogDeletionPolicy {
diff --git a/server/src/main/java/org/opensearch/index/translog/InternalTranslogFactory.java b/server/src/main/java/org/opensearch/index/translog/InternalTranslogFactory.java
new file mode 100644
index 0000000000000..d7be1250c0b5b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/InternalTranslogFactory.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import java.io.IOException;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+
+/**
+ * Translog Factory for the local on-disk {@link Translog}
+ *
+ * @opensearch.internal
+ */
+public class InternalTranslogFactory implements TranslogFactory {
+
+    @Override
+    public Translog newTranslog(
+        TranslogConfig translogConfig,
+        String translogUUID,
+        TranslogDeletionPolicy translogDeletionPolicy,
+        LongSupplier globalCheckpointSupplier,
+        LongSupplier primaryTermSupplier,
+        LongConsumer persistedSequenceNumberConsumer,
+        BooleanSupplier primaryModeSupplier
+    ) throws IOException {
+
+        return new LocalTranslog(
+            translogConfig,
+            translogUUID,
+            translogDeletionPolicy,
+            globalCheckpointSupplier,
+            primaryTermSupplier,
+            persistedSequenceNumberConsumer
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/InternalTranslogManager.java b/server/src/main/java/org/opensearch/index/translog/InternalTranslogManager.java
new file mode 100644
index 0000000000000..8c6bff591c1ec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/InternalTranslogManager.java
@@ -0,0 +1,460 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.engine.LifecycleAware;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.translog.listener.TranslogEventListener;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+/**
+ * The {@link TranslogManager} implementation capable of orchestrating all read/write {@link Translog} operations while
+ * interfacing with the {@link org.opensearch.index.engine.InternalEngine}
+ *
+ * @opensearch.internal
+ */
+public class InternalTranslogManager implements TranslogManager, Closeable {
+
+    private final ReleasableLock readLock;
+    private final LifecycleAware engineLifeCycleAware;
+    private final ShardId shardId;
+    private final Translog translog;
+    private final AtomicBoolean pendingTranslogRecovery = new AtomicBoolean(false);
+    private final TranslogEventListener translogEventListener;
+    private final Supplier<LocalCheckpointTracker> localCheckpointTrackerSupplier;
+    private final Logger logger;
+
+    public AtomicBoolean getPendingTranslogRecovery() {
+        return pendingTranslogRecovery;
+    }
+
+    public InternalTranslogManager(
+        TranslogConfig translogConfig,
+        LongSupplier primaryTermSupplier,
+        LongSupplier globalCheckpointSupplier,
+        TranslogDeletionPolicy translogDeletionPolicy,
+        ShardId shardId,
+        ReleasableLock readLock,
+        Supplier<LocalCheckpointTracker> localCheckpointTrackerSupplier,
+        String translogUUID,
+        TranslogEventListener translogEventListener,
+        LifecycleAware engineLifeCycleAware,
+        TranslogFactory translogFactory,
+        BooleanSupplier primaryModeSupplier
+    ) throws IOException {
+        this.shardId = shardId;
+        this.readLock = readLock;
+        this.engineLifeCycleAware = engineLifeCycleAware;
+        this.translogEventListener = translogEventListener;
+        this.localCheckpointTrackerSupplier = localCheckpointTrackerSupplier;
+        Translog translog = openTranslog(translogConfig, primaryTermSupplier, translogDeletionPolicy, globalCheckpointSupplier, seqNo -> {
+            final LocalCheckpointTracker tracker = localCheckpointTrackerSupplier.get();
+            assert tracker != null || getTranslog(true).isOpen() == false;
+            if (tracker != null) {
+                tracker.markSeqNoAsPersisted(seqNo);
+            }
+        }, translogUUID, translogFactory, primaryModeSupplier);
+        assert translog.getGeneration() != null;
+        this.translog = translog;
+        assert pendingTranslogRecovery.get() == false : "translog recovery can't be pending before we set it";
+        // don't allow commits until we are done with recovering
+        pendingTranslogRecovery.set(true);
+        this.logger = Loggers.getLogger(getClass(), shardId);
+    }
+
+    /**
+     * Rolls the translog generation and cleans unneeded.
+     */
+    @Override
+    public void rollTranslogGeneration() throws TranslogException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            engineLifeCycleAware.ensureOpen();
+            translog.rollGeneration();
+            translog.trimUnreferencedReaders();
+        } catch (AlreadyClosedException e) {
+            translogEventListener.onFailure("translog roll generation failed", e);
+            throw e;
+        } catch (Exception e) {
+            try {
+                translogEventListener.onFailure("translog roll generation failed", e);
+            } catch (Exception inner) {
+                e.addSuppressed(inner);
+            }
+            throw new TranslogException(shardId, "failed to roll translog", e);
+        }
+    }
+
+    /**
+     * Performs recovery from the transaction log up to {@code recoverUpToSeqNo} (inclusive).
+     * This operation will close the engine if the recovery fails.
+     *  @param translogRecoveryRunner the translog recovery runner
+     * @param recoverUpToSeqNo       the upper bound, inclusive, of sequence number to be recovered
+     * @return the total number of operations recovered
+     */
+    @Override
+    public int recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long localCheckpoint, long recoverUpToSeqNo)
+        throws IOException {
+        int opsRecovered = 0;
+        translogEventListener.onBeginTranslogRecovery();
+        try (ReleasableLock ignored = readLock.acquire()) {
+            engineLifeCycleAware.ensureOpen();
+            if (pendingTranslogRecovery.get() == false) {
+                throw new IllegalStateException("Engine has already been recovered");
+            }
+            try {
+                opsRecovered = recoverFromTranslogInternal(translogRecoveryRunner, localCheckpoint, recoverUpToSeqNo);
+            } catch (Exception e) {
+                try {
+                    pendingTranslogRecovery.set(true); // just play safe and never allow commits on this see #ensureCanFlush
+                    translogEventListener.onFailure("failed to recover from translog", e);
+                } catch (Exception inner) {
+                    e.addSuppressed(inner);
+                }
+                throw e;
+            }
+        }
+        return opsRecovered;
+    }
+
+    private int recoverFromTranslogInternal(TranslogRecoveryRunner translogRecoveryRunner, long localCheckpoint, long recoverUpToSeqNo) {
+        final int opsRecovered;
+        if (localCheckpoint < recoverUpToSeqNo) {
+            try (Translog.Snapshot snapshot = translog.newSnapshot(localCheckpoint + 1, recoverUpToSeqNo)) {
+                opsRecovered = translogRecoveryRunner.run(snapshot);
+            } catch (Exception e) {
+                throw new TranslogException(shardId, "failed to recover from translog", e);
+            }
+        } else {
+            opsRecovered = 0;
+        }
+        // flush if we recovered something or if we have references to older translogs
+        // note: if opsRecovered == 0 and we have older translogs it means they are corrupted or 0 length.
+        assert pendingTranslogRecovery.get() : "translogRecovery is not pending but should be";
+        pendingTranslogRecovery.set(false); // we are good - now we can commit
+        logger.trace(
+            () -> new ParameterizedMessage(
+                "flushing post recovery from translog: ops recovered [{}], current translog generation [{}]",
+                opsRecovered,
+                translog.currentFileGeneration()
+            )
+        );
+        translogEventListener.onAfterTranslogRecovery();
+        return opsRecovered;
+    }
+
+    /**
+     * Checks if the underlying storage sync is required.
+     */
+    @Override
+    public boolean isTranslogSyncNeeded() {
+        return getTranslog(true).syncNeeded();
+    }
+
+    /**
+     * Ensures that all locations in the given stream have been written to the underlying storage.
+     */
+    @Override
+    public boolean ensureTranslogSynced(Stream<Translog.Location> locations) throws IOException {
+        final boolean synced = translog.ensureSynced(locations);
+        if (synced) {
+            translogEventListener.onAfterTranslogSync();
+        }
+        return synced;
+    }
+
+    /**
+     * Syncs the translog and invokes the listener
+     * @throws IOException the exception on sync failure
+     */
+    @Override
+    public void syncTranslog() throws IOException {
+        translog.sync();
+        translogEventListener.onAfterTranslogSync();
+    }
+
+    @Override
+    public TranslogStats getTranslogStats() {
+        return getTranslog(true).stats();
+    }
+
+    /**
+     * Returns the last location that the translog of this engine has written into.
+     */
+    @Override
+    public Translog.Location getTranslogLastWriteLocation() {
+        return getTranslog(true).getLastWriteLocation();
+    }
+
+    /**
+     * checks and removes translog files that no longer need to be retained. See
+     * {@link org.opensearch.index.translog.TranslogDeletionPolicy} for details
+     */
+    @Override
+    public void trimUnreferencedTranslogFiles() throws TranslogException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            engineLifeCycleAware.ensureOpen();
+            translog.trimUnreferencedReaders();
+        } catch (AlreadyClosedException e) {
+            translogEventListener.onFailure("translog trimming unreferenced translog failed", e);
+            throw e;
+        } catch (Exception e) {
+            try {
+                translogEventListener.onFailure("translog trimming unreferenced translog failed", e);
+            } catch (Exception inner) {
+                e.addSuppressed(inner);
+            }
+            throw new TranslogException(shardId, "failed to trim unreferenced translog translog", e);
+        }
+    }
+
+    /**
+     * Tests whether or not the translog generation should be rolled to a new generation.
+     * This test is based on the size of the current generation compared to the configured generation threshold size.
+     *
+     * @return {@code true} if the current generation should be rolled to a new generation
+     */
+    @Override
+    public boolean shouldRollTranslogGeneration() {
+        return getTranslog(true).shouldRollGeneration();
+    }
+
+    /**
+     * Trims translog for terms below <code>belowTerm</code> and seq# above <code>aboveSeqNo</code>
+     * @see Translog#trimOperations(long, long)
+     */
+    @Override
+    public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws TranslogException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            engineLifeCycleAware.ensureOpen();
+            translog.trimOperations(belowTerm, aboveSeqNo);
+        } catch (AlreadyClosedException e) {
+            translogEventListener.onFailure("translog operations trimming failed", e);
+            throw e;
+        } catch (Exception e) {
+            try {
+                translogEventListener.onFailure("translog operations trimming failed", e);
+            } catch (Exception inner) {
+                e.addSuppressed(inner);
+            }
+            throw new TranslogException(shardId, "failed to trim translog operations", e);
+        }
+    }
+
+    /**
+     * This method replays translog to restore the Lucene index which might be reverted previously.
+     * This ensures that all acknowledged writes are restored correctly when this engine is promoted.
+     *
+     * @return the number of translog operations have been recovered
+     */
+    @Override
+    public int restoreLocalHistoryFromTranslog(long processedCheckpoint, TranslogRecoveryRunner translogRecoveryRunner) throws IOException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            engineLifeCycleAware.ensureOpen();
+            try (Translog.Snapshot snapshot = getTranslog(true).newSnapshot(processedCheckpoint + 1, Long.MAX_VALUE)) {
+                return translogRecoveryRunner.run(snapshot);
+            }
+        }
+    }
+
+    /**
+     * Ensures that the flushes can succeed if there are no pending translog recovery
+     */
+    @Override
+    public void ensureCanFlush() {
+        // translog recovery happens after the engine is fully constructed.
+        // If we are in this stage we have to prevent flushes from this
+        // engine otherwise we might loose documents if the flush succeeds
+        // and the translog recovery fails when we "commit" the translog on flush.
+        if (pendingTranslogRecovery.get()) {
+            throw new IllegalStateException(shardId.toString() + " flushes are disabled - pending translog recovery");
+        }
+    }
+
+    @Override
+    public void setMinSeqNoToKeep(long seqNo) {
+        translog.setMinSeqNoToKeep(seqNo);
+    }
+
+    public void onDelete() {
+        translog.onDelete();
+    }
+
+    @Override
+    public Translog.TranslogGeneration getTranslogGeneration() {
+        return translog.getGeneration();
+    }
+
+    /**
+     * Reads operations from the translog
+     * @param location location of translog
+     * @return the translog operation
+     * @throws IOException throws an IO exception
+     */
+    @Override
+    public Translog.Operation readOperation(Translog.Location location) throws IOException {
+        return translog.readOperation(location);
+    }
+
+    /**
+     * Adds an operation to the translog
+     * @param operation operation to add to translog
+     * @return the location in the translog
+     * @throws IOException throws an IO exception
+     */
+    @Override
+    public Translog.Location add(Translog.Operation operation) throws IOException {
+        return translog.add(operation);
+    }
+
+    /**
+     * Do not replay translog operations, but make the engine be ready.
+     */
+    @Override
+    public void skipTranslogRecovery() {
+        assert pendingTranslogRecovery.get() : "translogRecovery is not pending but should be";
+        pendingTranslogRecovery.set(false); // we are good - now we can commit
+    }
+
+    // visible for testing
+    // TODO refactor tests to remove public access to translog
+    public Translog getTranslog() {
+        return translog;
+    }
+
+    private Translog getTranslog(boolean ensureOpen) {
+        if (ensureOpen) {
+            this.engineLifeCycleAware.ensureOpen();
+        }
+        return translog;
+    }
+
+    protected Translog openTranslog(
+        TranslogConfig translogConfig,
+        LongSupplier primaryTermSupplier,
+        TranslogDeletionPolicy translogDeletionPolicy,
+        LongSupplier globalCheckpointSupplier,
+        LongConsumer persistedSequenceNumberConsumer,
+        String translogUUID,
+        TranslogFactory translogFactory,
+        BooleanSupplier primaryModeSupplier
+    ) throws IOException {
+        return translogFactory.newTranslog(
+            translogConfig,
+            translogUUID,
+            translogDeletionPolicy,
+            globalCheckpointSupplier,
+            primaryTermSupplier,
+            persistedSequenceNumberConsumer,
+            primaryModeSupplier
+        );
+    }
+
+    /**
+     * Retrieves last synced global checkpoint
+     * @return last synced global checkpoint
+     */
+    public long getLastSyncedGlobalCheckpoint() {
+        return translog.getLastSyncedGlobalCheckpoint();
+    }
+
+    /**
+     * Retrieves the max seq no
+     * @return max seq no
+     */
+    public long getMaxSeqNo() {
+        return translog.getMaxSeqNo();
+    }
+
+    /**
+     * Trims unreferenced translog generations by asking {@link TranslogDeletionPolicy} for the minimum
+     * required generation
+     */
+    public void trimUnreferencedReaders() throws IOException {
+        translog.trimUnreferencedReaders();
+    }
+
+    /**
+     * Retrieves the translog deletion policy
+     * @return TranslogDeletionPolicy
+     */
+    public TranslogDeletionPolicy getDeletionPolicy() {
+        return translog.getDeletionPolicy();
+    }
+
+    /**
+     * Retrieves the underlying translog tragic exception
+     * @return the tragic exception
+     */
+    public Exception getTragicExceptionIfClosed() {
+        return translog.isOpen() == false ? translog.getTragicException() : null;
+    }
+
+    /**
+     * Retrieves the translog unique identifier
+     * @return the uuid of the translog
+     */
+    public String getTranslogUUID() {
+        return translog.getTranslogUUID();
+    }
+
+    /**
+     *
+     * @param localCheckpointOfLastCommit local checkpoint reference of last commit to translog
+     * @param flushThreshold threshold to flush to translog
+     * @return if the translog should be flushed
+     */
+    public boolean shouldPeriodicallyFlush(long localCheckpointOfLastCommit, long flushThreshold) {
+        final long translogGenerationOfLastCommit = translog.getMinGenerationForSeqNo(
+            localCheckpointOfLastCommit + 1
+        ).translogFileGeneration;
+        if (translog.sizeInBytesByMinGen(translogGenerationOfLastCommit) < flushThreshold) {
+            return false;
+        }
+        /*
+         * We flush to reduce the size of uncommitted translog but strictly speaking the uncommitted size won't always be
+         * below the flush-threshold after a flush. To avoid getting into an endless loop of flushing, we only enable the
+         * periodically flush condition if this condition is disabled after a flush. The condition will change if the new
+         * commit points to the later generation the last commit's(eg. gen-of-last-commit < gen-of-new-commit)[1].
+         *
+         * When the local checkpoint equals to max_seqno, and translog-gen of the last commit equals to translog-gen of
+         * the new commit, we know that the last generation must contain operations because its size is above the flush
+         * threshold and the flush-threshold is guaranteed to be higher than an empty translog by the setting validation.
+         * This guarantees that the new commit will point to the newly rolled generation. In fact, this scenario only
+         * happens when the generation-threshold is close to or above the flush-threshold; otherwise we have rolled
+         * generations as the generation-threshold was reached, then the first condition (eg. [1]) is already satisfied.
+         *
+         * This method is to maintain translog only, thus IndexWriter#hasUncommittedChanges condition is not considered.
+         */
+        final long translogGenerationOfNewCommit = translog.getMinGenerationForSeqNo(
+            localCheckpointTrackerSupplier.get().getProcessedCheckpoint() + 1
+        ).translogFileGeneration;
+        return translogGenerationOfLastCommit < translogGenerationOfNewCommit
+            || localCheckpointTrackerSupplier.get().getProcessedCheckpoint() == localCheckpointTrackerSupplier.get().getMaxSeqNo();
+    }
+
+    @Override
+    public void close() throws IOException {
+        IOUtils.closeWhileHandlingException(translog);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/LocalTranslog.java b/server/src/main/java/org/opensearch/index/translog/LocalTranslog.java
new file mode 100644
index 0000000000000..22dba3973cfc1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/LocalTranslog.java
@@ -0,0 +1,160 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.common.util.io.IOUtils;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+
+/**
+ * A {@link Translog} implementation that creates translog files in local filesystem.
+ * @opensearch.internal
+ */
+public class LocalTranslog extends Translog {
+
+    /**
+     * Creates a new Translog instance. This method will create a new transaction log unless the given {@link TranslogGeneration} is
+     * {@code null}. If the generation is {@code null} this method is destructive and will delete all files in the translog path given. If
+     * the generation is not {@code null}, this method tries to open the given translog generation. The generation is treated as the last
+     * generation referenced from already committed data. This means all operations that have not yet been committed should be in the
+     * translog file referenced by this generation. The translog creation will fail if this generation can't be opened.
+     *
+     * @param config                   the configuration of this translog
+     * @param translogUUID             the translog uuid to open, null for a new translog
+     * @param deletionPolicy           an instance of {@link TranslogDeletionPolicy} that controls when a translog file can be safely
+     *                                 deleted
+     * @param globalCheckpointSupplier a supplier for the global checkpoint
+     * @param primaryTermSupplier      a supplier for the latest value of primary term of the owning index shard. The latest term value is
+     *                                 examined and stored in the header whenever a new generation is rolled. It's guaranteed from outside
+     *                                 that a new generation is rolled when the term is increased. This guarantee allows to us to validate
+     *                                 and reject operation whose term is higher than the primary term stored in the translog header.
+     * @param persistedSequenceNumberConsumer a callback that's called whenever an operation with a given sequence number is successfully
+     *                                        persisted.
+     */
+    public LocalTranslog(
+        final TranslogConfig config,
+        final String translogUUID,
+        TranslogDeletionPolicy deletionPolicy,
+        final LongSupplier globalCheckpointSupplier,
+        final LongSupplier primaryTermSupplier,
+        final LongConsumer persistedSequenceNumberConsumer
+    ) throws IOException {
+        super(config, translogUUID, deletionPolicy, globalCheckpointSupplier, primaryTermSupplier, persistedSequenceNumberConsumer);
+        try {
+            final Checkpoint checkpoint = readCheckpoint(location);
+            final Path nextTranslogFile = location.resolve(getFilename(checkpoint.generation + 1));
+            final Path currentCheckpointFile = location.resolve(getCommitCheckpointFileName(checkpoint.generation));
+            // this is special handling for error condition when we create a new writer but we fail to bake
+            // the newly written file (generation+1) into the checkpoint. This is still a valid state
+            // we just need to cleanup before we continue
+            // we hit this before and then blindly deleted the new generation even though we managed to bake it in and then hit this:
+            // https://discuss.elastic.co/t/cannot-recover-index-because-of-missing-tanslog-files/38336 as an example
+            //
+            // For this to happen we must have already copied the translog.ckp file into translog-gen.ckp so we first check if that
+            // file exists. If not we don't even try to clean it up and wait until we fail creating it
+            assert Files.exists(nextTranslogFile) == false || Files.size(nextTranslogFile) <= TranslogHeader.headerSizeInBytes(translogUUID)
+                : "unexpected translog file: [" + nextTranslogFile + "]";
+            if (Files.exists(currentCheckpointFile) // current checkpoint is already copied
+                && Files.deleteIfExists(nextTranslogFile)) { // delete it and log a warning
+                logger.warn(
+                    "deleted previously created, but not yet committed, next generation [{}]. This can happen due to a"
+                        + " tragic exception when creating a new generation",
+                    nextTranslogFile.getFileName()
+                );
+            }
+            this.readers.addAll(recoverFromFiles(checkpoint));
+            if (readers.isEmpty()) {
+                throw new IllegalStateException("at least one reader must be recovered");
+            }
+            boolean success = false;
+            current = null;
+            try {
+                current = createWriter(
+                    checkpoint.generation + 1,
+                    getMinFileGeneration(),
+                    checkpoint.globalCheckpoint,
+                    persistedSequenceNumberConsumer
+                );
+                success = true;
+            } finally {
+                // we have to close all the recovered ones otherwise we leak file handles here
+                // for instance if we have a lot of tlog and we can't create the writer we keep on holding
+                // on to all the uncommitted tlog files if we don't close
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(readers);
+                }
+            }
+        } catch (Exception e) {
+            // close the opened translog files if we fail to create a new translog...
+            IOUtils.closeWhileHandlingException(current);
+            IOUtils.closeWhileHandlingException(readers);
+            throw e;
+        }
+    }
+
+    /**
+     * Ensures that the given location has be synced / written to the underlying storage.
+     *
+     * @return Returns <code>true</code> iff this call caused an actual sync operation otherwise <code>false</code>
+     */
+    @Override
+    public boolean ensureSynced(Location location) throws IOException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            if (location.generation == current.getGeneration()) { // if we have a new one it's already synced
+                ensureOpen();
+                return current.syncUpTo(location.translogLocation + location.size);
+            }
+        } catch (final Exception ex) {
+            closeOnTragicEvent(ex);
+            throw ex;
+        }
+        return false;
+    }
+
+    /**
+     * return stats
+     */
+    @Override
+    public TranslogStats stats() {
+        // acquire lock to make the two numbers roughly consistent (no file change half way)
+        try (ReleasableLock lock = readLock.acquire()) {
+            long uncommittedGen = getMinGenerationForSeqNo(deletionPolicy.getLocalCheckpointOfSafeCommit() + 1).translogFileGeneration;
+            return new TranslogStats(
+                totalOperations(),
+                sizeInBytes(),
+                totalOperationsByMinGen(uncommittedGen),
+                sizeInBytesByMinGen(uncommittedGen),
+                earliestLastModifiedAge()
+            );
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        assert Translog.calledFromOutsideOrViaTragedyClose()
+            : "Translog.close method is called from inside Translog, but not via closeOnTragicEvent method";
+        if (closed.compareAndSet(false, true)) {
+            try (ReleasableLock lock = writeLock.acquire()) {
+                try {
+                    current.sync();
+                } finally {
+                    closeFilesIfNoPendingRetentionLocks();
+                }
+            } finally {
+                logger.debug("translog closed");
+            }
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/MultiSnapshot.java b/server/src/main/java/org/opensearch/index/translog/MultiSnapshot.java
index 9a2fd009f4216..941283afe5908 100644
--- a/server/src/main/java/org/opensearch/index/translog/MultiSnapshot.java
+++ b/server/src/main/java/org/opensearch/index/translog/MultiSnapshot.java
@@ -32,16 +32,19 @@
 
 package org.opensearch.index.translog;
 
-import com.carrotsearch.hppc.LongObjectHashMap;
 import org.opensearch.index.seqno.CountedBitSet;
 import org.opensearch.index.seqno.SequenceNumbers;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * A snapshot composed out of multiple snapshots
+ *
+ * @opensearch.internal
  */
 final class MultiSnapshot implements Translog.Snapshot {
 
@@ -96,9 +99,14 @@ public void close() throws IOException {
         onClose.close();
     }
 
+    /**
+     * Sequence number set
+     *
+     * @opensearch.internal
+     */
     static final class SeqNoSet {
         static final short BIT_SET_SIZE = 1024;
-        private final LongObjectHashMap<CountedBitSet> bitSets = new LongObjectHashMap<>();
+        private final Map<Long, CountedBitSet> bitSets = new HashMap<>();
 
         /**
          * Marks this sequence number and returns {@code true} if it is seen before.
diff --git a/server/src/main/java/org/opensearch/index/translog/NoOpTranslogManager.java b/server/src/main/java/org/opensearch/index/translog/NoOpTranslogManager.java
new file mode 100644
index 0000000000000..a4ac59690d014
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/NoOpTranslogManager.java
@@ -0,0 +1,125 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.io.IOException;
+import java.util.stream.Stream;
+
+/**
+ * The no-op implementation of {@link TranslogManager} that doesn't perform any operation
+ *
+ * @opensearch.internal
+ */
+public class NoOpTranslogManager implements TranslogManager {
+
+    private final Translog.Snapshot emptyTranslogSnapshot;
+    private final ReleasableLock readLock;
+    private final Runnable ensureOpen;
+    private final ShardId shardId;
+    private final TranslogStats translogStats;
+
+    public NoOpTranslogManager(
+        ShardId shardId,
+        ReleasableLock readLock,
+        Runnable ensureOpen,
+        TranslogStats translogStats,
+        Translog.Snapshot emptyTranslogSnapshot
+    ) throws IOException {
+        this.emptyTranslogSnapshot = emptyTranslogSnapshot;
+        this.readLock = readLock;
+        this.shardId = shardId;
+        this.ensureOpen = ensureOpen;
+        this.translogStats = translogStats;
+    }
+
+    @Override
+    public void rollTranslogGeneration() throws TranslogException {}
+
+    @Override
+    public int recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long localCheckpoint, long recoverUpToSeqNo)
+        throws IOException {
+        try (ReleasableLock ignored = readLock.acquire()) {
+            ensureOpen.run();
+            try (Translog.Snapshot snapshot = emptyTranslogSnapshot) {
+                translogRecoveryRunner.run(snapshot);
+            } catch (final Exception e) {
+                throw new TranslogException(shardId, "failed to recover from empty translog snapshot", e);
+            }
+        }
+        return emptyTranslogSnapshot.totalOperations();
+    }
+
+    @Override
+    public boolean isTranslogSyncNeeded() {
+        return false;
+    }
+
+    @Override
+    public boolean ensureTranslogSynced(Stream<Translog.Location> locations) {
+        return false;
+    }
+
+    @Override
+    public void syncTranslog() throws IOException {}
+
+    @Override
+    public TranslogStats getTranslogStats() {
+        return translogStats;
+    }
+
+    @Override
+    public Translog.Location getTranslogLastWriteLocation() {
+        return new Translog.Location(0, 0, 0);
+    }
+
+    @Override
+    public void trimUnreferencedTranslogFiles() throws TranslogException {}
+
+    @Override
+    public boolean shouldRollTranslogGeneration() {
+        return false;
+    }
+
+    @Override
+    public void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws TranslogException {}
+
+    @Override
+    public void ensureCanFlush() {}
+
+    @Override
+    public void setMinSeqNoToKeep(long seqNo) {}
+
+    @Override
+    public int restoreLocalHistoryFromTranslog(long processedCheckpoint, TranslogRecoveryRunner translogRecoveryRunner) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public void skipTranslogRecovery() {}
+
+    @Override
+    public Translog.Operation readOperation(Translog.Location location) throws IOException {
+        return null;
+    }
+
+    @Override
+    public Translog.Location add(Translog.Operation operation) throws IOException {
+        return new Translog.Location(0, 0, 0);
+    }
+
+    public void onDelete() {}
+
+    @Override
+    public Translog.TranslogGeneration getTranslogGeneration() {
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/RemoteBlobStoreInternalTranslogFactory.java b/server/src/main/java/org/opensearch/index/translog/RemoteBlobStoreInternalTranslogFactory.java
new file mode 100644
index 0000000000000..1e2cb388e690e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/RemoteBlobStoreInternalTranslogFactory.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+import java.util.function.Supplier;
+
+/**
+ * Translog Factory for the remotefs  translog {@link RemoteFsTranslog}
+ *
+ * @opensearch.internal
+ */
+public class RemoteBlobStoreInternalTranslogFactory implements TranslogFactory {
+
+    private final Repository repository;
+
+    private final ThreadPool threadPool;
+
+    private final RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+
+    public RemoteBlobStoreInternalTranslogFactory(
+        Supplier<RepositoriesService> repositoriesServiceSupplier,
+        ThreadPool threadPool,
+        String repositoryName,
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker
+    ) {
+        Repository repository;
+        try {
+            repository = repositoriesServiceSupplier.get().repository(repositoryName);
+        } catch (RepositoryMissingException ex) {
+            throw new IllegalArgumentException("Repository should be created before creating index with remote_store enabled setting", ex);
+        }
+        this.repository = repository;
+        this.threadPool = threadPool;
+        this.remoteTranslogTransferTracker = remoteTranslogTransferTracker;
+    }
+
+    @Override
+    public Translog newTranslog(
+        TranslogConfig config,
+        String translogUUID,
+        TranslogDeletionPolicy deletionPolicy,
+        LongSupplier globalCheckpointSupplier,
+        LongSupplier primaryTermSupplier,
+        LongConsumer persistedSequenceNumberConsumer,
+        BooleanSupplier primaryModeSupplier
+    ) throws IOException {
+
+        assert repository instanceof BlobStoreRepository : "repository should be instance of BlobStoreRepository";
+        BlobStoreRepository blobStoreRepository = ((BlobStoreRepository) repository);
+        return new RemoteFsTranslog(
+            config,
+            translogUUID,
+            deletionPolicy,
+            globalCheckpointSupplier,
+            primaryTermSupplier,
+            persistedSequenceNumberConsumer,
+            blobStoreRepository,
+            threadPool,
+            primaryModeSupplier,
+            remoteTranslogTransferTracker
+        );
+    }
+
+    public Repository getRepository() {
+        return repository;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/RemoteFsTranslog.java b/server/src/main/java/org/opensearch/index/translog/RemoteFsTranslog.java
new file mode 100644
index 0000000000000..29c825fd383c5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/RemoteFsTranslog.java
@@ -0,0 +1,547 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.translog.transfer.BlobStoreTransferService;
+import org.opensearch.index.translog.transfer.FileTransferTracker;
+import org.opensearch.index.translog.transfer.TransferSnapshot;
+import org.opensearch.index.translog.transfer.TranslogCheckpointTransferSnapshot;
+import org.opensearch.index.translog.transfer.TranslogTransferManager;
+import org.opensearch.index.translog.transfer.TranslogTransferMetadata;
+import org.opensearch.index.translog.transfer.listener.TranslogTransferListener;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.Semaphore;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+
+/**
+ * A Translog implementation which syncs local FS with a remote store
+ * The current impl uploads translog , ckp and metadata to remote store
+ * for every sync, post syncing to disk. Post that, a new generation is
+ * created.
+ *
+ * @opensearch.internal
+ */
+public class RemoteFsTranslog extends Translog {
+
+    private final Logger logger;
+    private final BlobStoreRepository blobStoreRepository;
+    private final TranslogTransferManager translogTransferManager;
+    private final FileTransferTracker fileTransferTracker;
+    private final BooleanSupplier primaryModeSupplier;
+    private final RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+    private volatile long maxRemoteTranslogGenerationUploaded;
+
+    private volatile long minSeqNoToKeep;
+
+    // min generation referred by last uploaded translog
+    private volatile long minRemoteGenReferenced;
+
+    // clean up translog folder uploaded by previous primaries once
+    private final SetOnce<Boolean> olderPrimaryCleaned = new SetOnce<>();
+
+    private static final int REMOTE_DELETION_PERMITS = 2;
+    private static final int DOWNLOAD_RETRIES = 2;
+    public static final String TRANSLOG = "translog";
+
+    // Semaphore used to allow only single remote generation to happen at a time
+    private final Semaphore remoteGenerationDeletionPermits = new Semaphore(REMOTE_DELETION_PERMITS);
+
+    public RemoteFsTranslog(
+        TranslogConfig config,
+        String translogUUID,
+        TranslogDeletionPolicy deletionPolicy,
+        LongSupplier globalCheckpointSupplier,
+        LongSupplier primaryTermSupplier,
+        LongConsumer persistedSequenceNumberConsumer,
+        BlobStoreRepository blobStoreRepository,
+        ThreadPool threadPool,
+        BooleanSupplier primaryModeSupplier,
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker
+    ) throws IOException {
+        super(config, translogUUID, deletionPolicy, globalCheckpointSupplier, primaryTermSupplier, persistedSequenceNumberConsumer);
+        logger = Loggers.getLogger(getClass(), shardId);
+        this.blobStoreRepository = blobStoreRepository;
+        this.primaryModeSupplier = primaryModeSupplier;
+        this.remoteTranslogTransferTracker = remoteTranslogTransferTracker;
+        fileTransferTracker = new FileTransferTracker(shardId, remoteTranslogTransferTracker);
+        this.translogTransferManager = buildTranslogTransferManager(
+            blobStoreRepository,
+            threadPool,
+            shardId,
+            fileTransferTracker,
+            remoteTranslogTransferTracker
+        );
+        try {
+            download(translogTransferManager, location, logger);
+            Checkpoint checkpoint = readCheckpoint(location);
+            this.readers.addAll(recoverFromFiles(checkpoint));
+            if (readers.isEmpty()) {
+                String errorMsg = String.format(Locale.ROOT, "%s at least one reader must be recovered", shardId);
+                logger.error(errorMsg);
+                throw new IllegalStateException(errorMsg);
+            }
+            boolean success = false;
+            current = null;
+            try {
+                current = createWriter(
+                    checkpoint.generation + 1,
+                    getMinFileGeneration(),
+                    checkpoint.globalCheckpoint,
+                    persistedSequenceNumberConsumer
+                );
+                success = true;
+            } finally {
+                // we have to close all the recovered ones otherwise we leak file handles here
+                // for instance if we have a lot of tlog and we can't create the writer we keep
+                // on holding
+                // on to all the uncommitted tlog files if we don't close
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(readers);
+                }
+            }
+        } catch (Exception e) {
+            // close the opened translog files if we fail to create a new translog...
+            IOUtils.closeWhileHandlingException(current);
+            IOUtils.closeWhileHandlingException(readers);
+            throw e;
+        }
+    }
+
+    // visible for testing
+    RemoteTranslogTransferTracker getRemoteTranslogTracker() {
+        return remoteTranslogTransferTracker;
+    }
+
+    public static void download(Repository repository, ShardId shardId, ThreadPool threadPool, Path location, Logger logger)
+        throws IOException {
+        assert repository instanceof BlobStoreRepository : String.format(
+            Locale.ROOT,
+            "%s repository should be instance of BlobStoreRepository",
+            shardId
+        );
+        BlobStoreRepository blobStoreRepository = (BlobStoreRepository) repository;
+        // We use a dummy stats tracker to ensure the flow doesn't break.
+        // TODO: To be revisited as part of https://github.com/opensearch-project/OpenSearch/issues/7567
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = new RemoteTranslogTransferTracker(shardId, 1000);
+        FileTransferTracker fileTransferTracker = new FileTransferTracker(shardId, remoteTranslogTransferTracker);
+        TranslogTransferManager translogTransferManager = buildTranslogTransferManager(
+            blobStoreRepository,
+            threadPool,
+            shardId,
+            fileTransferTracker,
+            remoteTranslogTransferTracker
+        );
+        RemoteFsTranslog.download(translogTransferManager, location, logger);
+    }
+
+    static void download(TranslogTransferManager translogTransferManager, Path location, Logger logger) throws IOException {
+        /*
+        In Primary to Primary relocation , there can be concurrent upload and download of translog.
+        While translog files are getting downloaded by new primary, it might hence be deleted by the primary
+        Hence we retry if tlog/ckp files are not found .
+
+        This doesn't happen in last download , where it is ensured that older primary has stopped modifying tlog data.
+         */
+        IOException ex = null;
+        for (int i = 0; i <= DOWNLOAD_RETRIES; i++) {
+            try {
+                downloadOnce(translogTransferManager, location, logger);
+                return;
+            } catch (FileNotFoundException | NoSuchFileException e) {
+                // continue till download retries
+                ex = e;
+            }
+        }
+        logger.debug("Exhausted all download retries during translog/checkpoint file download");
+        throw ex;
+    }
+
+    static private void downloadOnce(TranslogTransferManager translogTransferManager, Path location, Logger logger) throws IOException {
+        logger.debug("Downloading translog files from remote");
+        RemoteTranslogTransferTracker statsTracker = translogTransferManager.getRemoteTranslogTransferTracker();
+        long prevDownloadBytesSucceeded = statsTracker.getDownloadBytesSucceeded();
+        long prevDownloadTimeInMillis = statsTracker.getTotalDownloadTimeInMillis();
+        TranslogTransferMetadata translogMetadata = translogTransferManager.readMetadata();
+        if (translogMetadata != null) {
+            if (Files.notExists(location)) {
+                Files.createDirectories(location);
+            }
+
+            // Delete translog files on local before downloading from remote
+            for (Path file : FileSystemUtils.files(location)) {
+                Files.delete(file);
+            }
+
+            Map<String, String> generationToPrimaryTermMapper = translogMetadata.getGenerationToPrimaryTermMapper();
+            for (long i = translogMetadata.getGeneration(); i >= translogMetadata.getMinTranslogGeneration(); i--) {
+                String generation = Long.toString(i);
+                translogTransferManager.downloadTranslog(generationToPrimaryTermMapper.get(generation), generation, location);
+            }
+            logger.info(
+                "Downloaded translog and checkpoint files from={} to={}",
+                translogMetadata.getMinTranslogGeneration(),
+                translogMetadata.getGeneration()
+            );
+
+            statsTracker.recordDownloadStats(prevDownloadBytesSucceeded, prevDownloadTimeInMillis);
+
+            // We copy the latest generation .ckp file to translog.ckp so that flows that depend on
+            // existence of translog.ckp file work in the same way
+            Files.copy(
+                location.resolve(Translog.getCommitCheckpointFileName(translogMetadata.getGeneration())),
+                location.resolve(Translog.CHECKPOINT_FILE_NAME)
+            );
+        }
+        logger.debug("downloadOnce execution completed");
+    }
+
+    public static TranslogTransferManager buildTranslogTransferManager(
+        BlobStoreRepository blobStoreRepository,
+        ThreadPool threadPool,
+        ShardId shardId,
+        FileTransferTracker fileTransferTracker,
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker
+    ) {
+        return new TranslogTransferManager(
+            shardId,
+            new BlobStoreTransferService(blobStoreRepository.blobStore(), threadPool),
+            blobStoreRepository.basePath().add(shardId.getIndex().getUUID()).add(String.valueOf(shardId.id())).add(TRANSLOG),
+            fileTransferTracker,
+            remoteTranslogTransferTracker
+        );
+    }
+
+    @Override
+    public boolean ensureSynced(Location location) throws IOException {
+        assert location.generation <= current.getGeneration();
+        if (location.generation == current.getGeneration()) {
+            ensureOpen();
+            return prepareAndUpload(primaryTermSupplier.getAsLong(), location.generation);
+        }
+        return false;
+    }
+
+    @Override
+    public void rollGeneration() throws IOException {
+        syncBeforeRollGeneration();
+        if (current.totalOperations() == 0 && primaryTermSupplier.getAsLong() == current.getPrimaryTerm()) {
+            return;
+        }
+        prepareAndUpload(primaryTermSupplier.getAsLong(), null);
+    }
+
+    private boolean prepareAndUpload(Long primaryTerm, Long generation) throws IOException {
+        try (Releasable ignored = writeLock.acquire()) {
+            if (generation == null || generation == current.getGeneration()) {
+                try {
+                    final TranslogReader reader = current.closeIntoReader();
+                    readers.add(reader);
+                    copyCheckpointTo(location.resolve(getCommitCheckpointFileName(current.getGeneration())));
+                    if (closed.get() == false) {
+                        logger.trace("Creating new writer for gen: [{}]", current.getGeneration() + 1);
+                        current = createWriter(current.getGeneration() + 1);
+                    }
+                    assert writeLock.isHeldByCurrentThread() : "Write lock must be held before we acquire the read lock";
+                    // Here we are downgrading the write lock by acquiring the read lock and releasing the write lock
+                    // This ensures that other threads can still acquire the read locks while also protecting the
+                    // readers and writer to not be mutated any further.
+                    readLock.acquire();
+                } catch (final Exception e) {
+                    tragedy.setTragicException(e);
+                    closeOnTragicEvent(e);
+                    throw e;
+                }
+            } else if (generation < current.getGeneration()) {
+                return false;
+            }
+        }
+
+        assert readLock.isHeldByCurrentThread() == true;
+        try (Releasable ignored = readLock; Releasable ignoredGenLock = deletionPolicy.acquireTranslogGen(getMinFileGeneration())) {
+            // Do we need remote writes in sync fashion ?
+            // If we don't , we should swallow FileAlreadyExistsException while writing to remote store
+            // and also verify for same during primary-primary relocation
+            // Writing remote in sync fashion doesn't hurt as global ckp update
+            // is not updated in remote translog except in primary to primary recovery.
+            if (generation == null) {
+                if (closed.get() == false) {
+                    return upload(primaryTerm, current.getGeneration() - 1);
+                } else {
+                    return upload(primaryTerm, current.getGeneration());
+                }
+            } else {
+                return upload(primaryTerm, generation);
+            }
+        }
+    }
+
+    private boolean upload(Long primaryTerm, Long generation) throws IOException {
+        // During primary relocation (primary-primary peer recovery), both the old and the new primary have engine
+        // created with the RemoteFsTranslog. Both primaries are equipped to upload the translogs. The primary mode check
+        // below ensures that the real primary only is uploading. Before the primary mode is set as true for the new
+        // primary, the engine is reset to InternalEngine which also initialises the RemoteFsTranslog which in turns
+        // downloads all the translogs from remote store and does a flush before the relocation finishes.
+        if (primaryModeSupplier.getAsBoolean() == false) {
+            logger.debug("skipped uploading translog for {} {}", primaryTerm, generation);
+            // NO-OP
+            return true;
+        }
+        logger.trace("uploading translog for {} {}", primaryTerm, generation);
+        try (
+            TranslogCheckpointTransferSnapshot transferSnapshotProvider = new TranslogCheckpointTransferSnapshot.Builder(
+                primaryTerm,
+                generation,
+                location,
+                readers,
+                Translog::getCommitCheckpointFileName,
+                config.getNodeId()
+            ).build()
+        ) {
+            return translogTransferManager.transferSnapshot(
+                transferSnapshotProvider,
+                new RemoteFsTranslogTransferListener(generation, primaryTerm)
+            );
+        }
+
+    }
+
+    // Visible for testing
+    public Set<String> allUploaded() {
+        return fileTransferTracker.allUploaded();
+    }
+
+    private boolean syncToDisk() throws IOException {
+        try (ReleasableLock lock = readLock.acquire()) {
+            return current.sync();
+        } catch (final Exception ex) {
+            closeOnTragicEvent(ex);
+            throw ex;
+        }
+    }
+
+    @Override
+    public void sync() throws IOException {
+        if (syncToDisk() || syncNeeded()) {
+            prepareAndUpload(primaryTermSupplier.getAsLong(), null);
+        }
+    }
+
+    /**
+     * Returns <code>true</code> if an fsync and/or remote transfer is required to ensure durability of the translogs operations or it's metadata.
+     */
+    public boolean syncNeeded() {
+        try (ReleasableLock lock = readLock.acquire()) {
+            return current.syncNeeded()
+                || (maxRemoteTranslogGenerationUploaded + 1 < this.currentFileGeneration() && current.totalOperations() == 0);
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        assert Translog.calledFromOutsideOrViaTragedyClose() : shardId
+            + "Translog.close method is called from inside Translog, but not via closeOnTragicEvent method";
+        if (closed.compareAndSet(false, true)) {
+            try (ReleasableLock lock = writeLock.acquire()) {
+                sync();
+            } finally {
+                logger.debug("translog closed");
+                closeFilesIfNoPendingRetentionLocks();
+            }
+        }
+    }
+
+    protected long getMinReferencedGen() throws IOException {
+        assert readLock.isHeldByCurrentThread() || writeLock.isHeldByCurrentThread();
+        long minReferencedGen = Math.min(
+            deletionPolicy.minTranslogGenRequired(readers, current),
+            minGenerationForSeqNo(minSeqNoToKeep, current, readers)
+        );
+
+        assert minReferencedGen >= getMinFileGeneration() : shardId
+            + " deletion policy requires a minReferenceGen of ["
+            + minReferencedGen
+            + "] but the lowest gen available is ["
+            + getMinFileGeneration()
+            + "]";
+        assert minReferencedGen <= currentFileGeneration() : shardId
+            + " deletion policy requires a minReferenceGen of ["
+            + minReferencedGen
+            + "] which is higher than the current generation ["
+            + currentFileGeneration()
+            + "]";
+        return minReferencedGen;
+    }
+
+    protected void setMinSeqNoToKeep(long seqNo) {
+        if (seqNo < this.minSeqNoToKeep) {
+            throw new IllegalArgumentException(
+                shardId + " min seq number required can't go backwards: " + "current [" + this.minSeqNoToKeep + "] new [" + seqNo + "]"
+            );
+        }
+        this.minSeqNoToKeep = seqNo;
+    }
+
+    @Override
+    public void trimUnreferencedReaders() throws IOException {
+        // clean up local translog files and updates readers
+        super.trimUnreferencedReaders();
+
+        // Since remote generation deletion is async, this ensures that only one generation deletion happens at a time.
+        // Remote generations involves 2 async operations - 1) Delete translog generation files 2) Delete metadata files
+        // We try to acquire 2 permits and if we can not, we return from here itself.
+        if (remoteGenerationDeletionPermits.tryAcquire(REMOTE_DELETION_PERMITS) == false) {
+            return;
+        }
+
+        // cleans up remote translog files not referenced in latest uploaded metadata.
+        // This enables us to restore translog from the metadata in case of failover or relocation.
+        Set<Long> generationsToDelete = new HashSet<>();
+        for (long generation = minRemoteGenReferenced - 1; generation >= 0; generation--) {
+            if (fileTransferTracker.uploaded(Translog.getFilename(generation)) == false) {
+                break;
+            }
+            generationsToDelete.add(generation);
+        }
+        if (generationsToDelete.isEmpty() == false) {
+            deleteRemoteGeneration(generationsToDelete);
+            translogTransferManager.deleteStaleTranslogMetadataFilesAsync(remoteGenerationDeletionPermits::release);
+            deleteStaleRemotePrimaryTerms();
+        } else {
+            remoteGenerationDeletionPermits.release(REMOTE_DELETION_PERMITS);
+        }
+    }
+
+    /**
+     * Deletes remote translog and metadata files asynchronously corresponding to the generations.
+     * @param generations generations to be deleted.
+     */
+    private void deleteRemoteGeneration(Set<Long> generations) {
+        translogTransferManager.deleteGenerationAsync(
+            primaryTermSupplier.getAsLong(),
+            generations,
+            remoteGenerationDeletionPermits::release
+        );
+    }
+
+    /**
+     * This method must be called only after there are valid generations to delete in trimUnreferencedReaders as it ensures
+     * implicitly that minimum primary term in latest translog metadata in remote store is the current primary term.
+     * <br>
+     * This will also delete all stale translog metadata files from remote except the latest basis the metadata file comparator.
+     */
+    private void deleteStaleRemotePrimaryTerms() {
+        // The deletion of older translog files in remote store is on best-effort basis, there is a possibility that there
+        // are older files that are no longer needed and should be cleaned up. In here, we delete all files that are part
+        // of older primary term.
+        if (olderPrimaryCleaned.trySet(Boolean.TRUE)) {
+            if (readers.isEmpty()) {
+                logger.trace("Translog reader list is empty, returning from deleteStaleRemotePrimaryTerms");
+                return;
+            }
+            // First we delete all stale primary terms folders from remote store
+            long minimumReferencedPrimaryTerm = readers.stream().map(BaseTranslogReader::getPrimaryTerm).min(Long::compare).get();
+            translogTransferManager.deletePrimaryTermsAsync(minimumReferencedPrimaryTerm);
+        }
+    }
+
+    public static void cleanup(Repository repository, ShardId shardId, ThreadPool threadPool) throws IOException {
+        assert repository instanceof BlobStoreRepository : "repository should be instance of BlobStoreRepository";
+        BlobStoreRepository blobStoreRepository = (BlobStoreRepository) repository;
+        // We use a dummy stats tracker to ensure the flow doesn't break.
+        // TODO: To be revisited as part of https://github.com/opensearch-project/OpenSearch/issues/7567
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = new RemoteTranslogTransferTracker(shardId, 1000);
+        FileTransferTracker fileTransferTracker = new FileTransferTracker(shardId, remoteTranslogTransferTracker);
+        TranslogTransferManager translogTransferManager = buildTranslogTransferManager(
+            blobStoreRepository,
+            threadPool,
+            shardId,
+            fileTransferTracker,
+            remoteTranslogTransferTracker
+        );
+        // clean up all remote translog files
+        translogTransferManager.deleteTranslogFiles();
+    }
+
+    protected void onDelete() {
+        if (primaryModeSupplier.getAsBoolean() == false) {
+            logger.trace("skipped delete translog");
+            // NO-OP
+            return;
+        }
+        // clean up all remote translog files
+        translogTransferManager.delete();
+    }
+
+    // Visible for testing
+    boolean isRemoteGenerationDeletionPermitsAvailable() {
+        return remoteGenerationDeletionPermits.availablePermits() == REMOTE_DELETION_PERMITS;
+    }
+
+    /**
+     * TranslogTransferListener implementation for RemoteFsTranslog
+     *
+     * @opensearch.internal
+     */
+    private class RemoteFsTranslogTransferListener implements TranslogTransferListener {
+
+        /**
+         * Generation for the translog
+         */
+        private final Long generation;
+
+        /**
+         * Primary Term for the translog
+         */
+        private final Long primaryTerm;
+
+        RemoteFsTranslogTransferListener(Long generation, Long primaryTerm) {
+            this.generation = generation;
+            this.primaryTerm = primaryTerm;
+        }
+
+        @Override
+        public void onUploadComplete(TransferSnapshot transferSnapshot) throws IOException {
+            maxRemoteTranslogGenerationUploaded = generation;
+            minRemoteGenReferenced = getMinFileGeneration();
+            logger.trace("uploaded translog for {} {} ", primaryTerm, generation);
+        }
+
+        @Override
+        public void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) throws IOException {
+            if (ex instanceof IOException) {
+                throw (IOException) ex;
+            } else {
+                throw (RuntimeException) ex;
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/RemoteTranslogStats.java b/server/src/main/java/org/opensearch/index/translog/RemoteTranslogStats.java
new file mode 100644
index 0000000000000..966f8ebc2875a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/RemoteTranslogStats.java
@@ -0,0 +1,192 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStats;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Encapsulates the stats related to Remote Translog Store operations
+ *
+ * @opensearch.internal
+ */
+public class RemoteTranslogStats implements ToXContentFragment, Writeable {
+    /**
+     * Total number of Remote Translog Store uploads that have been started
+     */
+    private long totalUploadsStarted;
+
+    /**
+     * Total number of Remote Translog Store uploads that have failed.
+     */
+    private long totalUploadsFailed;
+
+    /**
+     * Total number of Remote Translog Store uploads that have been successful.
+     */
+    private long totalUploadsSucceeded;
+
+    /**
+     * Total number of byte uploads to Remote Translog Store that have been started.
+     */
+    private long uploadBytesStarted;
+
+    /**
+     * Total number of byte uploads to Remote Translog Store that have failed.
+     */
+    private long uploadBytesFailed;
+
+    /**
+     * Total number of byte uploads to Remote Translog Store that have been successful.
+     */
+    private long uploadBytesSucceeded;
+
+    static final String REMOTE_STORE = "remote_store";
+
+    public RemoteTranslogStats() {}
+
+    public RemoteTranslogStats(StreamInput in) throws IOException {
+        this.totalUploadsStarted = in.readVLong();
+        this.totalUploadsFailed = in.readVLong();
+        this.totalUploadsSucceeded = in.readVLong();
+        this.uploadBytesStarted = in.readVLong();
+        this.uploadBytesFailed = in.readVLong();
+        this.uploadBytesSucceeded = in.readVLong();
+    }
+
+    public RemoteTranslogStats(RemoteTranslogTransferTracker.Stats transferTrackerStats) {
+        this.totalUploadsStarted = transferTrackerStats.totalUploadsStarted;
+        this.totalUploadsFailed = transferTrackerStats.totalUploadsFailed;
+        this.totalUploadsSucceeded = transferTrackerStats.totalUploadsSucceeded;
+        this.uploadBytesStarted = transferTrackerStats.uploadBytesStarted;
+        this.uploadBytesFailed = transferTrackerStats.uploadBytesFailed;
+        this.uploadBytesSucceeded = transferTrackerStats.uploadBytesSucceeded;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(totalUploadsStarted);
+        out.writeVLong(totalUploadsFailed);
+        out.writeVLong(totalUploadsSucceeded);
+        out.writeVLong(uploadBytesStarted);
+        out.writeVLong(uploadBytesFailed);
+        out.writeVLong(uploadBytesSucceeded);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        RemoteTranslogStats other = (RemoteTranslogStats) obj;
+
+        return this.totalUploadsStarted == other.totalUploadsStarted
+            && this.totalUploadsFailed == other.totalUploadsFailed
+            && this.totalUploadsSucceeded == other.totalUploadsSucceeded
+            && this.uploadBytesStarted == other.uploadBytesStarted
+            && this.uploadBytesFailed == other.uploadBytesFailed
+            && this.uploadBytesSucceeded == other.uploadBytesSucceeded;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(
+            totalUploadsStarted,
+            totalUploadsFailed,
+            totalUploadsSucceeded,
+            uploadBytesStarted,
+            uploadBytesFailed,
+            uploadBytesSucceeded
+        );
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(REMOTE_STORE);
+
+        builder.startObject(RemoteStoreStats.SubFields.UPLOAD);
+        addRemoteTranslogUploadStatsXContent(builder);
+        builder.endObject(); // translog.remote_store.upload
+
+        builder.endObject(); // translog.remote_store
+
+        return builder;
+    }
+
+    public long getTotalUploadsStarted() {
+        return totalUploadsStarted;
+    }
+
+    public long getTotalUploadsFailed() {
+        return totalUploadsFailed;
+    }
+
+    public long getTotalUploadsSucceeded() {
+        return totalUploadsSucceeded;
+    }
+
+    public long getUploadBytesStarted() {
+        return uploadBytesStarted;
+    }
+
+    public long getUploadBytesFailed() {
+        return uploadBytesFailed;
+    }
+
+    public long getUploadBytesSucceeded() {
+        return uploadBytesSucceeded;
+    }
+
+    public void add(RemoteTranslogStats other) {
+        if (other == null) {
+            return;
+        }
+
+        this.totalUploadsStarted += other.totalUploadsStarted;
+        this.totalUploadsFailed += other.totalUploadsFailed;
+        this.totalUploadsSucceeded += other.totalUploadsSucceeded;
+        this.uploadBytesStarted += other.uploadBytesStarted;
+        this.uploadBytesFailed += other.uploadBytesFailed;
+        this.uploadBytesSucceeded += other.uploadBytesSucceeded;
+    }
+
+    void addRemoteTranslogUploadStatsXContent(XContentBuilder builder) throws IOException {
+        builder.startObject(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS);
+        builder.field(RemoteStoreStats.SubFields.STARTED, totalUploadsStarted)
+            .field(RemoteStoreStats.SubFields.FAILED, totalUploadsFailed)
+            .field(RemoteStoreStats.SubFields.SUCCEEDED, totalUploadsSucceeded);
+        builder.endObject();
+
+        builder.startObject(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE);
+        builder.humanReadableField(
+            RemoteStoreStats.SubFields.STARTED_BYTES,
+            RemoteStoreStats.SubFields.STARTED,
+            new ByteSizeValue(uploadBytesStarted)
+        );
+        builder.humanReadableField(
+            RemoteStoreStats.SubFields.FAILED_BYTES,
+            RemoteStoreStats.SubFields.FAILED,
+            new ByteSizeValue(uploadBytesFailed)
+        );
+        builder.humanReadableField(
+            RemoteStoreStats.SubFields.SUCCEEDED_BYTES,
+            RemoteStoreStats.SubFields.SUCCEEDED,
+            new ByteSizeValue(uploadBytesSucceeded)
+        );
+        builder.endObject();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/TragicExceptionHolder.java b/server/src/main/java/org/opensearch/index/translog/TragicExceptionHolder.java
index 6a8fdc4a3d7a3..818d840cb11fd 100644
--- a/server/src/main/java/org/opensearch/index/translog/TragicExceptionHolder.java
+++ b/server/src/main/java/org/opensearch/index/translog/TragicExceptionHolder.java
@@ -37,6 +37,11 @@
 
 import java.util.concurrent.atomic.AtomicReference;
 
+/**
+ * Exception thrown if there are any massive OpenSearch failures
+ *
+ * @opensearch.internal
+ */
 public class TragicExceptionHolder {
     private final AtomicReference<Exception> tragedy = new AtomicReference<>();
 
diff --git a/server/src/main/java/org/opensearch/index/translog/Translog.java b/server/src/main/java/org/opensearch/index/translog/Translog.java
index 25d84efbee38f..baa3737d576de 100644
--- a/server/src/main/java/org/opensearch/index/translog/Translog.java
+++ b/server/src/main/java/org/opensearch/index/translog/Translog.java
@@ -36,19 +36,20 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.Engine;
@@ -59,7 +60,6 @@
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.AbstractIndexShardComponent;
 import org.opensearch.index.shard.IndexShardComponent;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.Closeable;
 import java.io.EOFException;
@@ -109,8 +109,10 @@
  * which is an fsynced copy of its last {@code translog.ckp} such that in disaster recovery last fsynced offsets, number of
  * operation etc. are still preserved.
  * </p>
+ *
+ * @opensearch.internal
  */
-public class Translog extends AbstractIndexShardComponent implements IndexShardComponent, Closeable {
+public abstract class Translog extends AbstractIndexShardComponent implements IndexShardComponent, Closeable {
 
     /*
      * TODO
@@ -132,21 +134,21 @@ public class Translog extends AbstractIndexShardComponent implements IndexShardC
     public static final int DEFAULT_HEADER_SIZE_IN_BYTES = TranslogHeader.headerSizeInBytes(UUIDs.randomBase64UUID());
 
     // the list of translog readers is guaranteed to be in order of translog generation
-    private final List<TranslogReader> readers = new ArrayList<>();
-    private final BigArrays bigArrays;
+    protected final List<TranslogReader> readers = new ArrayList<>();
+    protected final BigArrays bigArrays;
     protected final ReleasableLock readLock;
     protected final ReleasableLock writeLock;
-    private final Path location;
-    private TranslogWriter current;
+    protected final Path location;
+    protected TranslogWriter current;
 
     protected final TragicExceptionHolder tragedy = new TragicExceptionHolder();
-    private final AtomicBoolean closed = new AtomicBoolean();
-    private final TranslogConfig config;
-    private final LongSupplier globalCheckpointSupplier;
-    private final LongSupplier primaryTermSupplier;
-    private final String translogUUID;
-    private final TranslogDeletionPolicy deletionPolicy;
-    private final LongConsumer persistedSequenceNumberConsumer;
+    protected final AtomicBoolean closed = new AtomicBoolean();
+    protected final TranslogConfig config;
+    protected final LongSupplier globalCheckpointSupplier;
+    protected final LongSupplier primaryTermSupplier;
+    protected final String translogUUID;
+    protected final TranslogDeletionPolicy deletionPolicy;
+    protected final LongConsumer persistedSequenceNumberConsumer;
 
     /**
      * Creates a new Translog instance. This method will create a new transaction log unless the given {@link TranslogGeneration} is
@@ -188,61 +190,10 @@ public Translog(
         writeLock = new ReleasableLock(rwl.writeLock());
         this.location = config.getTranslogPath();
         Files.createDirectories(this.location);
-
-        try {
-            final Checkpoint checkpoint = readCheckpoint(location);
-            final Path nextTranslogFile = location.resolve(getFilename(checkpoint.generation + 1));
-            final Path currentCheckpointFile = location.resolve(getCommitCheckpointFileName(checkpoint.generation));
-            // this is special handling for error condition when we create a new writer but we fail to bake
-            // the newly written file (generation+1) into the checkpoint. This is still a valid state
-            // we just need to cleanup before we continue
-            // we hit this before and then blindly deleted the new generation even though we managed to bake it in and then hit this:
-            // https://discuss.elastic.co/t/cannot-recover-index-because-of-missing-tanslog-files/38336 as an example
-            //
-            // For this to happen we must have already copied the translog.ckp file into translog-gen.ckp so we first check if that
-            // file exists. If not we don't even try to clean it up and wait until we fail creating it
-            assert Files.exists(nextTranslogFile) == false || Files.size(nextTranslogFile) <= TranslogHeader.headerSizeInBytes(translogUUID)
-                : "unexpected translog file: [" + nextTranslogFile + "]";
-            if (Files.exists(currentCheckpointFile) // current checkpoint is already copied
-                && Files.deleteIfExists(nextTranslogFile)) { // delete it and log a warning
-                logger.warn(
-                    "deleted previously created, but not yet committed, next generation [{}]. This can happen due to a"
-                        + " tragic exception when creating a new generation",
-                    nextTranslogFile.getFileName()
-                );
-            }
-            this.readers.addAll(recoverFromFiles(checkpoint));
-            if (readers.isEmpty()) {
-                throw new IllegalStateException("at least one reader must be recovered");
-            }
-            boolean success = false;
-            current = null;
-            try {
-                current = createWriter(
-                    checkpoint.generation + 1,
-                    getMinFileGeneration(),
-                    checkpoint.globalCheckpoint,
-                    persistedSequenceNumberConsumer
-                );
-                success = true;
-            } finally {
-                // we have to close all the recovered ones otherwise we leak file handles here
-                // for instance if we have a lot of tlog and we can't create the writer we keep on holding
-                // on to all the uncommitted tlog files if we don't close
-                if (success == false) {
-                    IOUtils.closeWhileHandlingException(readers);
-                }
-            }
-        } catch (Exception e) {
-            // close the opened translog files if we fail to create a new translog...
-            IOUtils.closeWhileHandlingException(current);
-            IOUtils.closeWhileHandlingException(readers);
-            throw e;
-        }
     }
 
     /** recover all translog files found on disk */
-    private ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws IOException {
+    protected ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws IOException {
         boolean success = false;
         ArrayList<TranslogReader> foundTranslogs = new ArrayList<>();
         try (ReleasableLock ignored = writeLock.acquire()) {
@@ -253,7 +204,7 @@ private ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws
             // the generation id we found in the lucene commit. This gives for better error messages if the wrong
             // translog was found.
             for (long i = checkpoint.generation; i >= minGenerationToRecoverFrom; i--) {
-                Path committedTranslogFile = location.resolve(getFilename(i));
+                Path committedTranslogFile = location.resolve(Translog.getFilename(i));
                 if (Files.exists(committedTranslogFile) == false) {
                     throw new TranslogCorruptedException(
                         committedTranslogFile.toString(),
@@ -268,7 +219,7 @@ private ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws
                 }
                 final Checkpoint readerCheckpoint = i == checkpoint.generation
                     ? checkpoint
-                    : Checkpoint.read(location.resolve(getCommitCheckpointFileName(i)));
+                    : Checkpoint.read(location.resolve(Translog.getCommitCheckpointFileName(i)));
                 final TranslogReader reader = openReader(committedTranslogFile, readerCheckpoint);
                 assert reader.getPrimaryTerm() <= primaryTermSupplier.getAsLong() : "Primary terms go backwards; current term ["
                     + primaryTermSupplier.getAsLong()
@@ -285,11 +236,11 @@ private ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws
             // when we clean up files, we first update the checkpoint with a new minReferencedTranslog and then delete them;
             // if we crash just at the wrong moment, it may be that we leave one unreferenced file behind so we delete it if there
             IOUtils.deleteFilesIgnoringExceptions(
-                location.resolve(getFilename(minGenerationToRecoverFrom - 1)),
-                location.resolve(getCommitCheckpointFileName(minGenerationToRecoverFrom - 1))
+                location.resolve(Translog.getFilename(minGenerationToRecoverFrom - 1)),
+                location.resolve(Translog.getCommitCheckpointFileName(minGenerationToRecoverFrom - 1))
             );
 
-            Path commitCheckpoint = location.resolve(getCommitCheckpointFileName(checkpoint.generation));
+            Path commitCheckpoint = location.resolve(Translog.getCommitCheckpointFileName(checkpoint.generation));
             if (Files.exists(commitCheckpoint)) {
                 Checkpoint checkpointFromDisk = Checkpoint.read(commitCheckpoint);
                 if (checkpoint.equals(checkpointFromDisk) == false) {
@@ -315,7 +266,7 @@ private ArrayList<TranslogReader> recoverFromFiles(Checkpoint checkpoint) throws
         return foundTranslogs;
     }
 
-    private void copyCheckpointTo(Path targetPath) throws IOException {
+    protected void copyCheckpointTo(Path targetPath) throws IOException {
         // a temp file to copy checkpoint to - note it must be in on the same FS otherwise atomic move won't work
         final Path tempFile = Files.createTempFile(location, TRANSLOG_FILE_PREFIX, CHECKPOINT_SUFFIX);
         boolean tempFileRenamed = false;
@@ -381,7 +332,7 @@ public boolean isOpen() {
         return closed.get() == false;
     }
 
-    private static boolean calledFromOutsideOrViaTragedyClose() {
+    protected static boolean calledFromOutsideOrViaTragedyClose() {
         List<StackTraceElement> frames = Stream.of(Thread.currentThread().getStackTrace()).skip(3). // skip getStackTrace, current method
                                                                                                     // and close method frames
             limit(10). // limit depth of analysis to 10 frames, it should be enough to catch closing with, e.g. IOUtils
@@ -571,7 +522,8 @@ TranslogWriter createWriter(
                 primaryTermSupplier.getAsLong(),
                 tragedy,
                 persistedSequenceNumberConsumer,
-                bigArrays
+                bigArrays,
+                indexSettings.isRemoteTranslogStoreEnabled()
             );
         } catch (final IOException e) {
             throw new TranslogException(shardId, "failed to create new translog file", e);
@@ -815,7 +767,7 @@ public static String getFilename(long generation) {
         return TRANSLOG_FILE_PREFIX + generation + TRANSLOG_FILE_SUFFIX;
     }
 
-    static String getCommitCheckpointFileName(long generation) {
+    public static String getCommitCheckpointFileName(long generation) {
         return TRANSLOG_FILE_PREFIX + generation + CHECKPOINT_SUFFIX;
     }
 
@@ -866,18 +818,7 @@ public void trimOperations(long belowTerm, long aboveSeqNo) throws IOException {
      *
      * @return Returns <code>true</code> iff this call caused an actual sync operation otherwise <code>false</code>
      */
-    public boolean ensureSynced(Location location) throws IOException {
-        try (ReleasableLock lock = readLock.acquire()) {
-            if (location.generation == current.getGeneration()) { // if we have a new one it's already synced
-                ensureOpen();
-                return current.syncUpTo(location.translogLocation + location.size);
-            }
-        } catch (final Exception ex) {
-            closeOnTragicEvent(ex);
-            throw ex;
-        }
-        return false;
-    }
+    public abstract boolean ensureSynced(Location location) throws IOException;
 
     /**
      * Ensures that all locations in the given stream have been synced / written to the underlying storage.
@@ -950,6 +891,11 @@ public TranslogDeletionPolicy getDeletionPolicy() {
         return deletionPolicy;
     }
 
+    /**
+     * Location in the translot
+     *
+     * @opensearch.internal
+     */
     public static class Location implements Comparable<Location> {
 
         public final long generation;
@@ -1006,6 +952,8 @@ public int hashCode() {
 
     /**
      * A snapshot of the transaction log, allows to iterate over all the transaction log operations.
+     *
+     * @opensearch.internal
      */
     public interface Snapshot extends Closeable {
 
@@ -1033,6 +981,8 @@ default int skippedOperations() {
      * between {@code fromSeqNo} (inclusive) and {@code toSeqNo} (inclusive). This filtered snapshot
      * shares the same underlying resources with the {@code delegate} snapshot, therefore we should not
      * use the {@code delegate} after passing it to this filtered snapshot.
+     *
+     * @opensearch.internal
      */
     private static final class SeqNoFilterSnapshot implements Snapshot {
         private final Snapshot delegate;
@@ -1088,8 +1038,15 @@ public void close() throws IOException {
     /**
      * A generic interface representing an operation performed on the transaction log.
      * Each is associated with a type.
+     *
+     * @opensearch.internal
      */
     public interface Operation {
+        /**
+         * The type of operation
+         *
+         * @opensearch.internal
+         */
         enum Type {
             @Deprecated
             CREATE((byte) 1),
@@ -1177,6 +1134,11 @@ static void writeOperation(final StreamOutput output, final Operation operation)
 
     }
 
+    /**
+     * The source in the translog
+     *
+     * @opensearch.internal
+     */
     public static class Source {
 
         public final BytesReference source;
@@ -1189,6 +1151,11 @@ public Source(BytesReference source, String routing) {
 
     }
 
+    /**
+     * Indexing operation
+     *
+     * @opensearch.internal
+     */
     public static class Index implements Operation {
 
         public static final int FORMAT_6_0 = 8; // since 6.0.0
@@ -1376,6 +1343,11 @@ public long getAutoGeneratedIdTimestamp() {
 
     }
 
+    /**
+     * Delete operation
+     *
+     * @opensearch.internal
+     */
     public static class Delete implements Operation {
 
         private static final int FORMAT_6_0 = 4; // 6.0 - *
@@ -1507,6 +1479,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Translog no op
+     *
+     * @opensearch.internal
+     */
     public static class NoOp implements Operation {
 
         private final long seqNo;
@@ -1586,6 +1563,11 @@ public String toString() {
         }
     }
 
+    /**
+     * How to sync the translog
+     *
+     * @opensearch.internal
+     */
     public enum Durability {
 
         /**
@@ -1703,7 +1685,7 @@ public TranslogGeneration getMinGenerationForSeqNo(final long seqNo) {
         }
     }
 
-    private static long minGenerationForSeqNo(long seqNo, TranslogWriter writer, List<TranslogReader> readers) {
+    static long minGenerationForSeqNo(long seqNo, TranslogWriter writer, List<TranslogReader> readers) {
         long minGen = writer.generation;
         for (final TranslogReader reader : readers) {
             if (seqNo <= reader.getCheckpoint().maxEffectiveSeqNo()) {
@@ -1800,7 +1782,7 @@ public void trimUnreferencedReaders() throws IOException {
         }
     }
 
-    private long getMinReferencedGen() throws IOException {
+    protected long getMinReferencedGen() throws IOException {
         assert readLock.isHeldByCurrentThread() || writeLock.isHeldByCurrentThread();
         long minReferencedGen = Math.min(
             deletionPolicy.minTranslogGenRequired(readers, current),
@@ -1819,6 +1801,14 @@ private long getMinReferencedGen() throws IOException {
         return minReferencedGen;
     }
 
+    /*
+    Min Seq number required in translog to restore the complete data .
+    This might be required when segments are persisted via other mechanism than flush.
+     */
+    protected void setMinSeqNoToKeep(long seqNo) {}
+
+    protected void onDelete() {}
+
     /**
      * deletes all files associated with a reader. package-private to be able to simulate node failures at this point
      */
@@ -1842,6 +1832,8 @@ void closeFilesIfNoPendingRetentionLocks() throws IOException {
 
     /**
      * References a transaction log generation
+     *
+     * @opensearch.internal
      */
     public static final class TranslogGeneration {
         public final String translogUUID;
@@ -1865,7 +1857,7 @@ long getFirstOperationPosition() { // for testing
         return current.getFirstOperationOffset();
     }
 
-    private void ensureOpen() {
+    protected void ensureOpen() {
         if (closed.get()) {
             throw new AlreadyClosedException("translog is already closed", tragedy.get());
         }
@@ -2027,12 +2019,17 @@ public static String createEmptyTranslog(
             EMPTY_TRANSLOG_BUFFER_SIZE,
             minTranslogGeneration,
             initialGlobalCheckpoint,
-            () -> { throw new UnsupportedOperationException(); },
+            () -> {
+                throw new UnsupportedOperationException();
+            },
             () -> { throw new UnsupportedOperationException(); },
             primaryTerm,
             new TragicExceptionHolder(),
-            seqNo -> { throw new UnsupportedOperationException(); },
-            BigArrays.NON_RECYCLING_INSTANCE
+            seqNo -> {
+                throw new UnsupportedOperationException();
+            },
+            BigArrays.NON_RECYCLING_INSTANCE,
+            null
         );
         writer.close();
         return uuid;
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogCheckedContainer.java b/server/src/main/java/org/opensearch/index/translog/TranslogCheckedContainer.java
new file mode 100644
index 0000000000000..7e2a38559166f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogCheckedContainer.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.util.concurrent.ReleasableLock;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.zip.CRC32;
+import java.util.zip.Checksum;
+
+/**
+ * TranslogCheckedContainer is used to store, update and retrieve checksums for translog files.
+ *
+ * @opensearch.internal
+ */
+public class TranslogCheckedContainer {
+
+    private final Checksum checksum;
+    private final AtomicLong contentLength;
+    private final ReleasableLock updateLock = new ReleasableLock(new ReentrantLock());
+
+    /**
+     * Create TranslogCheckedContainer from provided bytes
+     *
+     * @param bytes The byte array to read from
+     */
+    public TranslogCheckedContainer(byte[] bytes) {
+        this.checksum = new CRC32();
+        this.contentLength = new AtomicLong();
+        updateFromBytes(bytes, 0, bytes.length);
+    }
+
+    /**
+     * Updates checksum from bytes array
+     *
+     * @param bytes  Input bytes to update checksum from
+     * @param offset Position in bytesReference to buffer bytes from
+     * @param len    Length of bytes to be buffered
+     */
+    public void updateFromBytes(byte[] bytes, int offset, int len) {
+        try (ReleasableLock ignored = updateLock.acquire()) {
+            checksum.update(bytes, offset, len);
+            updateContentLength(len);
+        }
+    }
+
+    private void updateContentLength(long delta) {
+        assert updateLock.isHeldByCurrentThread();
+        contentLength.addAndGet(delta);
+    }
+
+    /**
+     * @return checksum value of bytes which have been supplied to container so far.
+     */
+    public long getChecksum() {
+        return checksum.getValue();
+    }
+
+    /**
+     * @return Content length of bytes which have been supplied to container so far.
+     */
+    public long getContentLength() {
+        return contentLength.get();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogConfig.java b/server/src/main/java/org/opensearch/index/translog/TranslogConfig.java
index b2928c8340870..6e75ebd847b5e 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogConfig.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogConfig.java
@@ -32,18 +32,20 @@
 
 package org.opensearch.index.translog;
 
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 
 import java.nio.file.Path;
 
-/*
+/**
  * Holds all the configuration that is used to create a {@link Translog}.
  * Once {@link Translog} has been created with this object, changes to this
  * object will affect the {@link Translog} instance.
+ *
+ * @opensearch.internal
  */
 public final class TranslogConfig {
 
@@ -54,6 +56,7 @@ public final class TranslogConfig {
     private final ShardId shardId;
     private final Path translogPath;
     private final ByteSizeValue bufferSize;
+    private final String nodeId;
 
     /**
      * Creates a new TranslogConfig instance
@@ -62,16 +65,24 @@ public final class TranslogConfig {
      * @param indexSettings the index settings used to set internal variables
      * @param bigArrays a bigArrays instance used for temporarily allocating write operations
      */
-    public TranslogConfig(ShardId shardId, Path translogPath, IndexSettings indexSettings, BigArrays bigArrays) {
-        this(shardId, translogPath, indexSettings, bigArrays, DEFAULT_BUFFER_SIZE);
+    public TranslogConfig(ShardId shardId, Path translogPath, IndexSettings indexSettings, BigArrays bigArrays, String nodeId) {
+        this(shardId, translogPath, indexSettings, bigArrays, DEFAULT_BUFFER_SIZE, nodeId);
     }
 
-    TranslogConfig(ShardId shardId, Path translogPath, IndexSettings indexSettings, BigArrays bigArrays, ByteSizeValue bufferSize) {
+    TranslogConfig(
+        ShardId shardId,
+        Path translogPath,
+        IndexSettings indexSettings,
+        BigArrays bigArrays,
+        ByteSizeValue bufferSize,
+        String nodeId
+    ) {
         this.bufferSize = bufferSize;
         this.indexSettings = indexSettings;
         this.shardId = shardId;
         this.translogPath = translogPath;
         this.bigArrays = bigArrays;
+        this.nodeId = nodeId;
     }
 
     /**
@@ -108,4 +119,8 @@ public Path getTranslogPath() {
     public ByteSizeValue getBufferSize() {
         return bufferSize;
     }
+
+    public String getNodeId() {
+        return nodeId;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogCorruptedException.java b/server/src/main/java/org/opensearch/index/translog/TranslogCorruptedException.java
index 62159179eea13..4cc7844b1ced0 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogCorruptedException.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogCorruptedException.java
@@ -33,10 +33,15 @@
 package org.opensearch.index.translog;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if the translog is corrupted
+ *
+ * @opensearch.internal
+ */
 public class TranslogCorruptedException extends OpenSearchException {
     public TranslogCorruptedException(String source, String details) {
         super(corruptedMessage(source, details));
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicy.java b/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicy.java
index 62f2703becca7..99784b77c61f5 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicy.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicy.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.translog;
 
 import org.apache.lucene.util.Counter;
-import org.opensearch.Assertions;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.Assertions;
 import org.opensearch.index.seqno.SequenceNumbers;
 
 import java.io.IOException;
@@ -44,6 +44,11 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+/**
+ * Defines a translog deletion policy
+ *
+ * @opensearch.internal
+ */
 public abstract class TranslogDeletionPolicy {
 
     private final Map<Object, RuntimeException> openTranslogRef;
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicyFactory.java b/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicyFactory.java
index e964308a537ab..8f40fdc90368f 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicyFactory.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogDeletionPolicyFactory.java
@@ -13,6 +13,11 @@
 
 import java.util.function.Supplier;
 
+/**
+ * Factory to instantiate a translog deletion policy
+ *
+ * @opensearch.api
+ */
 @FunctionalInterface
 public interface TranslogDeletionPolicyFactory {
     TranslogDeletionPolicy create(IndexSettings settings, Supplier<RetentionLeases> supplier);
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogException.java b/server/src/main/java/org/opensearch/index/translog/TranslogException.java
index a162ab0fa019b..d7a8d649543d6 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogException.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogException.java
@@ -33,11 +33,16 @@
 package org.opensearch.index.translog;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there are any failures in the translog
+ *
+ * @opensearch.internal
+ */
 public class TranslogException extends OpenSearchException {
 
     public TranslogException(ShardId shardId, String msg) {
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogFactory.java b/server/src/main/java/org/opensearch/index/translog/TranslogFactory.java
new file mode 100644
index 0000000000000..ab8e2b7752e66
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogFactory.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import java.io.IOException;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+
+/**
+ * Translog Factory to enable creation of various local on-disk
+ * and remote store flavors of {@link Translog}
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface TranslogFactory {
+
+    Translog newTranslog(
+        final TranslogConfig config,
+        final String translogUUID,
+        final TranslogDeletionPolicy deletionPolicy,
+        final LongSupplier globalCheckpointSupplier,
+        final LongSupplier primaryTermSupplier,
+        final LongConsumer persistedSequenceNumberConsumer,
+        final BooleanSupplier primaryModeSupplier
+    ) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogHeader.java b/server/src/main/java/org/opensearch/index/translog/TranslogHeader.java
index c6158ecc942b6..7b5be9505f27a 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogHeader.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogHeader.java
@@ -40,12 +40,13 @@
 import org.apache.lucene.store.OutputStreamDataOutput;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.io.Channels;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.EOFException;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.channels.FileChannel;
 import java.nio.file.Path;
 
@@ -53,8 +54,10 @@
 
 /**
  * Each translog file is started with a translog header then followed by translog operations.
+ *
+ * @opensearch.internal
  */
-final class TranslogHeader {
+public final class TranslogHeader {
     public static final String TRANSLOG_CODEC = "translog";
 
     public static final int VERSION_CHECKSUMS = 1; // pre-2.0 - unsupported
@@ -134,9 +137,30 @@ static int readHeaderVersion(final Path path, final FileChannel channel, final S
     }
 
     /**
-     * Read a translog header from the given path and file channel
+     * Read a translog header from the given path and file channel and compare the given UUID
      */
     static TranslogHeader read(final String translogUUID, final Path path, final FileChannel channel) throws IOException {
+        TranslogHeader translogHeader = read(path, channel);
+        // verify UUID only after checksum, to ensure that UUID is not corrupted
+        final BytesRef expectedUUID = new BytesRef(translogUUID);
+        final BytesRef actualUUID = new BytesRef(translogHeader.translogUUID);
+        if (actualUUID.bytesEquals(expectedUUID) == false) {
+            throw new TranslogCorruptedException(
+                path.toString(),
+                "expected shard UUID "
+                    + translogUUID
+                    + " but got: "
+                    + translogHeader.translogUUID
+                    + " this translog file belongs to a different translog"
+            );
+        }
+        return translogHeader;
+    }
+
+    /**
+     * Read a translog header from the given path and file channel and compare the given UUID
+     */
+    public static TranslogHeader read(final Path path, final FileChannel channel) throws IOException {
         try {
             // This input is intentionally not closed because closing it will close the FileChannel.
             final BufferedChecksumStreamInput in = new BufferedChecksumStreamInput(
@@ -176,16 +200,7 @@ static TranslogHeader read(final String translogUUID, final Path path, final Fil
                 + channel.position()
                 + "]";
 
-            // verify UUID only after checksum, to ensure that UUID is not corrupted
-            final BytesRef expectedUUID = new BytesRef(translogUUID);
-            if (uuid.bytesEquals(expectedUUID) == false) {
-                throw new TranslogCorruptedException(
-                    path.toString(),
-                    "expected shard UUID " + expectedUUID + " but got: " + uuid + " this translog file belongs to a different translog"
-                );
-            }
-
-            return new TranslogHeader(translogUUID, primaryTerm, headerSizeInBytes);
+            return new TranslogHeader(uuid.utf8ToString(), primaryTerm, headerSizeInBytes);
         } catch (EOFException e) {
             throw new TranslogCorruptedException(path.toString(), "translog header truncated", e);
         }
@@ -211,12 +226,10 @@ private static void tryReportOldVersionError(final Path path, final FileChannel
     /**
      * Writes this header with the latest format into the file channel
      */
-    void write(final FileChannel channel) throws IOException {
+    void write(final OutputStream outputStream) throws IOException {
         // This output is intentionally not closed because closing it will close the FileChannel.
         @SuppressWarnings({ "IOResourceOpenedButNotSafelyClosed", "resource" })
-        final BufferedChecksumStreamOutput out = new BufferedChecksumStreamOutput(
-            new OutputStreamStreamOutput(java.nio.channels.Channels.newOutputStream(channel))
-        );
+        final BufferedChecksumStreamOutput out = new BufferedChecksumStreamOutput(new OutputStreamStreamOutput(outputStream));
         CodecUtil.writeHeader(new OutputStreamDataOutput(out), TRANSLOG_CODEC, CURRENT_VERSION);
         // Write uuid
         final BytesRef uuid = new BytesRef(translogUUID);
@@ -227,7 +240,14 @@ void write(final FileChannel channel) throws IOException {
         // Checksum header
         out.writeInt((int) out.getChecksum());
         out.flush();
-        channel.force(true);
+    }
+
+    void write(final FileChannel channel, boolean fsync) throws IOException {
+        OutputStream outputStream = java.nio.channels.Channels.newOutputStream(channel);
+        write(outputStream);
+        if (fsync == true) {
+            channel.force(true);
+        }
         assert channel.position() == headerSizeInBytes : "Header is not fully written; header size ["
             + headerSizeInBytes
             + "], channel position ["
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogManager.java b/server/src/main/java/org/opensearch/index/translog/TranslogManager.java
new file mode 100644
index 0000000000000..303e84dc2b228
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogManager.java
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import java.io.IOException;
+import java.util.stream.Stream;
+
+/**
+ * The interface that orchestrates Translog operations and manages the {@link Translog} and interfaces with the Engine
+ *
+ * @opensearch.internal
+ */
+public interface TranslogManager {
+
+    /**
+     * Rolls the translog generation and cleans unneeded.
+     */
+    void rollTranslogGeneration() throws TranslogException;
+
+    /**
+     * Performs recovery from the transaction log up to {@code recoverUpToSeqNo} (inclusive).
+     * This operation will close the engine if the recovery fails.
+     *
+     * @param translogRecoveryRunner the translog recovery runner
+     * @param recoverUpToSeqNo       the upper bound, inclusive, of sequence number to be recovered
+     * @return ops recovered
+     */
+    int recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long localCheckpoint, long recoverUpToSeqNo) throws IOException;
+
+    /**
+     * Checks if the underlying storage sync is required.
+     */
+    boolean isTranslogSyncNeeded();
+
+    /**
+     * Ensures that all locations in the given stream have been written to the underlying storage.
+     */
+    boolean ensureTranslogSynced(Stream<Translog.Location> locations) throws IOException;
+
+    /**
+     * Syncs translog to disk
+     * @throws IOException the exception while performing the sync operation
+     */
+    void syncTranslog() throws IOException;
+
+    /**
+     * Translog operation stats
+     * @return the translog stats
+     */
+    TranslogStats getTranslogStats();
+
+    /**
+     * Returns the last location that the translog of this engine has written into.
+     */
+    Translog.Location getTranslogLastWriteLocation();
+
+    /**
+     * checks and removes translog files that no longer need to be retained. See
+     * {@link org.opensearch.index.translog.TranslogDeletionPolicy} for details
+     */
+    void trimUnreferencedTranslogFiles() throws TranslogException;
+
+    /**
+     * Tests whether or not the translog generation should be rolled to a new generation.
+     * This test is based on the size of the current generation compared to the configured generation threshold size.
+     *
+     * @return {@code true} if the current generation should be rolled to a new generation
+     */
+    boolean shouldRollTranslogGeneration();
+
+    /**
+     * Trims translog for terms below <code>belowTerm</code> and seq# above <code>aboveSeqNo</code>
+     *
+     * @see Translog#trimOperations(long, long)
+     */
+    void trimOperationsFromTranslog(long belowTerm, long aboveSeqNo) throws TranslogException;
+
+    /**
+     * This method replays translog to restore the Lucene index which might be reverted previously.
+     * This ensures that all acknowledged writes are restored correctly when this engine is promoted.
+     *
+     * @return the number of translog operations have been recovered
+     */
+    int restoreLocalHistoryFromTranslog(long processedCheckpoint, TranslogRecoveryRunner translogRecoveryRunner) throws IOException;
+
+    /**
+     * Do not replay translog operations, but make the engine be ready.
+     */
+    void skipTranslogRecovery();
+
+    /**
+     * Reads operations for the translog
+     * @param location the location in the translog
+     * @return the translog operation
+     * @throws IOException throws an IO exception when reading the file fails
+     */
+    Translog.Operation readOperation(Translog.Location location) throws IOException;
+
+    /**
+     * Adds an operation to the translog
+     * @param operation to add to translog
+     * @return the location in the translog
+     * @throws IOException throws an IO exception if adding an operation fails
+     */
+    Translog.Location add(Translog.Operation operation) throws IOException;
+
+    /**
+     * Checks if the translog has a pending recovery
+     */
+    void ensureCanFlush();
+
+    /**
+     *
+     * @param seqNo : operations greater or equal to seqNo should be persisted
+     * This might be required when segments are persisted via other mechanism than flush.
+     */
+    void setMinSeqNoToKeep(long seqNo);
+
+    /*
+    Clean up if any needed on deletion of index
+     */
+    void onDelete();
+
+    Translog.TranslogGeneration getTranslogGeneration();
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogReader.java b/server/src/main/java/org/opensearch/index/translog/TranslogReader.java
index 3c47ce2207e4b..9ea3328587645 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogReader.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogReader.java
@@ -33,8 +33,9 @@
 package org.opensearch.index.translog;
 
 import org.apache.lucene.store.AlreadyClosedException;
+import org.opensearch.common.Nullable;
 import org.opensearch.common.io.Channels;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.seqno.SequenceNumbers;
 
 import java.io.Closeable;
@@ -50,6 +51,8 @@
 
 /**
  * an immutable translog filereader
+ *
+ * @opensearch.internal
  */
 public class TranslogReader extends BaseTranslogReader implements Closeable {
     protected final long length;
@@ -57,6 +60,11 @@ public class TranslogReader extends BaseTranslogReader implements Closeable {
     private final Checkpoint checkpoint;
     protected final AtomicBoolean closed = new AtomicBoolean(false);
 
+    @Nullable
+    private final Long translogChecksum;
+    @Nullable
+    private final Long checkpointChecksum;
+
     /**
      * Create a translog writer against the specified translog file channel.
      *
@@ -65,11 +73,34 @@ public class TranslogReader extends BaseTranslogReader implements Closeable {
      * @param path       the path to the translog
      * @param header     the header of the translog file
      */
-    TranslogReader(final Checkpoint checkpoint, final FileChannel channel, final Path path, final TranslogHeader header) {
+    TranslogReader(
+        final Checkpoint checkpoint,
+        final FileChannel channel,
+        final Path path,
+        final TranslogHeader header,
+        final Long translogChecksum
+    ) throws IOException {
         super(checkpoint.generation, channel, path, header);
         this.length = checkpoint.offset;
         this.totalOperations = checkpoint.numOps;
         this.checkpoint = checkpoint;
+        this.translogChecksum = translogChecksum;
+        this.checkpointChecksum = (translogChecksum != null) ? calculateCheckpointChecksum(checkpoint, path) : null;
+    }
+
+    private static Long calculateCheckpointChecksum(Checkpoint checkpoint, Path path) throws IOException {
+        TranslogCheckedContainer checkpointCheckedContainer = new TranslogCheckedContainer(
+            Checkpoint.createCheckpointBytes(path.getParent().resolve(Translog.CHECKPOINT_FILE_NAME), checkpoint)
+        );
+        return checkpointCheckedContainer.getChecksum();
+    }
+
+    public Long getTranslogChecksum() {
+        return translogChecksum;
+    }
+
+    public Long getCheckpointChecksum() {
+        return checkpointChecksum;
     }
 
     /**
@@ -85,7 +116,7 @@ public class TranslogReader extends BaseTranslogReader implements Closeable {
     public static TranslogReader open(final FileChannel channel, final Path path, final Checkpoint checkpoint, final String translogUUID)
         throws IOException {
         final TranslogHeader header = TranslogHeader.read(translogUUID, path, channel);
-        return new TranslogReader(checkpoint, channel, path, header);
+        return new TranslogReader(checkpoint, channel, path, header, null);
     }
 
     /**
@@ -113,9 +144,9 @@ TranslogReader closeIntoTrimmedReader(long aboveSeqNo, ChannelFactory channelFac
 
                     IOUtils.fsync(checkpointFile.getParent(), true);
 
-                    newReader = new TranslogReader(newCheckpoint, channel, path, header);
+                    newReader = new TranslogReader(newCheckpoint, channel, path, header, translogChecksum);
                 } else {
-                    newReader = new TranslogReader(checkpoint, channel, path, header);
+                    newReader = new TranslogReader(checkpoint, channel, path, header, translogChecksum);
                 }
                 toCloseOnFailure = null;
                 return newReader;
@@ -136,7 +167,7 @@ public int totalOperations() {
     }
 
     @Override
-    final Checkpoint getCheckpoint() {
+    final public Checkpoint getCheckpoint() {
         return checkpoint;
     }
 
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogRecoveryRunner.java b/server/src/main/java/org/opensearch/index/translog/TranslogRecoveryRunner.java
new file mode 100644
index 0000000000000..91c9a95b07d58
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogRecoveryRunner.java
@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import java.io.IOException;
+
+/**
+ * The interface that defines how {@link Translog.Snapshot} will get replayed into the Engine
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface TranslogRecoveryRunner {
+
+    /**
+     * Recovers a translog snapshot
+     * @param snapshot the snapshot of translog operations
+     * @return recoveredOps
+     * @throws IOException exception while recovering operations
+     */
+    int run(Translog.Snapshot snapshot) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogSnapshot.java b/server/src/main/java/org/opensearch/index/translog/TranslogSnapshot.java
index c9b1383bb0206..89718156cbbe8 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogSnapshot.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogSnapshot.java
@@ -38,6 +38,11 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 
+/**
+ * A snapshot of translog operations
+ *
+ * @opensearch.internal
+ */
 final class TranslogSnapshot extends BaseTranslogReader {
 
     private final int totalOperations;
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogStats.java b/server/src/main/java/org/opensearch/index/translog/TranslogStats.java
index 427802140d927..a4699cea671a0 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogStats.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogStats.java
@@ -31,25 +31,39 @@
 
 package org.opensearch.index.translog;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.Version;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Translog statistics
+ *
+ * @opensearch.internal
+ */
 public class TranslogStats implements Writeable, ToXContentFragment {
-
+    private static final String TRANSLOG = "translog";
     private long translogSizeInBytes;
     private int numberOfOperations;
     private long uncommittedSizeInBytes;
     private int uncommittedOperations;
     private long earliestLastModifiedAge;
 
-    public TranslogStats() {}
+    /**
+     * Stats related to the Remote Translog Store operations
+     */
+    private final RemoteTranslogStats remoteTranslogStats;
+
+    public TranslogStats() {
+        remoteTranslogStats = new RemoteTranslogStats();
+    }
 
     public TranslogStats(StreamInput in) throws IOException {
         numberOfOperations = in.readVInt();
@@ -57,6 +71,9 @@ public TranslogStats(StreamInput in) throws IOException {
         uncommittedOperations = in.readVInt();
         uncommittedSizeInBytes = in.readVLong();
         earliestLastModifiedAge = in.readVLong();
+        remoteTranslogStats = in.getVersion().onOrAfter(Version.V_2_10_0)
+            ? in.readOptionalWriteable(RemoteTranslogStats::new)
+            : new RemoteTranslogStats();
     }
 
     public TranslogStats(
@@ -81,27 +98,37 @@ public TranslogStats(
         if (earliestLastModifiedAge < 0) {
             throw new IllegalArgumentException("earliestLastModifiedAge must be >= 0");
         }
+
         this.numberOfOperations = numberOfOperations;
         this.translogSizeInBytes = translogSizeInBytes;
         this.uncommittedSizeInBytes = uncommittedSizeInBytes;
         this.uncommittedOperations = uncommittedOperations;
         this.earliestLastModifiedAge = earliestLastModifiedAge;
+        this.remoteTranslogStats = new RemoteTranslogStats();
+    }
+
+    public void addRemoteTranslogStats(RemoteTranslogStats remoteTranslogStats) {
+        if (this.remoteTranslogStats != null) {
+            this.remoteTranslogStats.add(remoteTranslogStats);
+        }
     }
 
-    public void add(TranslogStats translogStats) {
-        if (translogStats == null) {
+    public void add(TranslogStats other) {
+        if (other == null) {
             return;
         }
 
-        this.numberOfOperations += translogStats.numberOfOperations;
-        this.translogSizeInBytes += translogStats.translogSizeInBytes;
-        this.uncommittedOperations += translogStats.uncommittedOperations;
-        this.uncommittedSizeInBytes += translogStats.uncommittedSizeInBytes;
+        this.numberOfOperations += other.numberOfOperations;
+        this.translogSizeInBytes += other.translogSizeInBytes;
+        this.uncommittedOperations += other.uncommittedOperations;
+        this.uncommittedSizeInBytes += other.uncommittedSizeInBytes;
         if (this.earliestLastModifiedAge == 0) {
-            this.earliestLastModifiedAge = translogStats.earliestLastModifiedAge;
+            this.earliestLastModifiedAge = other.earliestLastModifiedAge;
         } else {
-            this.earliestLastModifiedAge = Math.min(this.earliestLastModifiedAge, translogStats.earliestLastModifiedAge);
+            this.earliestLastModifiedAge = Math.min(this.earliestLastModifiedAge, other.earliestLastModifiedAge);
         }
+
+        addRemoteTranslogStats(other.remoteTranslogStats);
     }
 
     public long getTranslogSizeInBytes() {
@@ -126,21 +153,26 @@ public long getEarliestLastModifiedAge() {
         return earliestLastModifiedAge;
     }
 
+    public RemoteTranslogStats getRemoteTranslogStats() {
+        return remoteTranslogStats;
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        builder.startObject("translog");
-        builder.field("operations", numberOfOperations);
-        builder.humanReadableField("size_in_bytes", "size", new ByteSizeValue(translogSizeInBytes));
-        builder.field("uncommitted_operations", uncommittedOperations);
-        builder.humanReadableField("uncommitted_size_in_bytes", "uncommitted_size", new ByteSizeValue(uncommittedSizeInBytes));
-        builder.field("earliest_last_modified_age", earliestLastModifiedAge);
+        builder.startObject(TRANSLOG);
+        addLocalTranslogStatsXContent(builder);
+        if (remoteTranslogStats != null) {
+            builder = remoteTranslogStats.toXContent(builder, params);
+        }
+
         builder.endObject();
+
         return builder;
     }
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     @Override
@@ -150,5 +182,16 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeVInt(uncommittedOperations);
         out.writeVLong(uncommittedSizeInBytes);
         out.writeVLong(earliestLastModifiedAge);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalWriteable(remoteTranslogStats);
+        }
+    }
+
+    private void addLocalTranslogStatsXContent(XContentBuilder builder) throws IOException {
+        builder.field("operations", numberOfOperations);
+        builder.humanReadableField("size_in_bytes", "size", new ByteSizeValue(translogSizeInBytes));
+        builder.field("uncommitted_operations", uncommittedOperations);
+        builder.humanReadableField("uncommitted_size_in_bytes", "uncommitted_size", new ByteSizeValue(uncommittedSizeInBytes));
+        builder.field("earliest_last_modified_age", earliestLastModifiedAge);
     }
 }
diff --git a/server/src/main/java/org/opensearch/index/translog/TranslogWriter.java b/server/src/main/java/org/opensearch/index/translog/TranslogWriter.java
index 66241f7b6847f..a5f0607431a8b 100644
--- a/server/src/main/java/org/opensearch/index/translog/TranslogWriter.java
+++ b/server/src/main/java/org/opensearch/index/translog/TranslogWriter.java
@@ -32,35 +32,37 @@
 
 package org.opensearch.index.translog;
 
-import com.carrotsearch.hppc.LongArrayList;
-import com.carrotsearch.hppc.procedures.LongProcedure;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.Assertions;
+import org.opensearch.common.Nullable;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Channels;
 import org.opensearch.common.io.DiskIoBufferPool;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
 import org.opensearch.common.lease.Releasables;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 
+import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -68,6 +70,11 @@
 import java.util.function.LongConsumer;
 import java.util.function.LongSupplier;
 
+/**
+ * Writer that writes operations to the translog
+ *
+ * @opensearch.internal
+ */
 public class TranslogWriter extends BaseTranslogReader implements Closeable {
 
     private final ShardId shardId;
@@ -98,13 +105,18 @@ public class TranslogWriter extends BaseTranslogReader implements Closeable {
     // lock order synchronized(syncLock) -> try(Releasable lock = writeLock.acquire()) -> synchronized(this)
     private final Object syncLock = new Object();
 
-    private LongArrayList nonFsyncedSequenceNumbers = new LongArrayList(64);
+    private List<Long> nonFsyncedSequenceNumbers = new ArrayList<>(64);
     private final int forceWriteThreshold;
     private volatile long bufferedBytes;
     private ReleasableBytesStreamOutput buffer;
 
     private final Map<Long, Tuple<BytesReference, Exception>> seenSequenceNumbers;
 
+    @Nullable
+    private final TranslogCheckedContainer translogCheckedContainer;
+
+    private final Boolean remoteTranslogEnabled;
+
     private TranslogWriter(
         final ShardId shardId,
         final Checkpoint initialCheckpoint,
@@ -118,7 +130,9 @@ private TranslogWriter(
         TranslogHeader header,
         final TragicExceptionHolder tragedy,
         final LongConsumer persistedSequenceNumberConsumer,
-        final BigArrays bigArrays
+        final BigArrays bigArrays,
+        TranslogCheckedContainer translogCheckedContainer,
+        Boolean remoteTranslogEnabled
     ) throws IOException {
         super(initialCheckpoint.generation, channel, path, header);
         assert initialCheckpoint.offset == channel.position() : "initial checkpoint offset ["
@@ -143,6 +157,8 @@ private TranslogWriter(
         this.bigArrays = bigArrays;
         this.seenSequenceNumbers = Assertions.ENABLED ? new HashMap<>() : null;
         this.tragedy = tragedy;
+        this.translogCheckedContainer = translogCheckedContainer;
+        this.remoteTranslogEnabled = remoteTranslogEnabled;
     }
 
     public static TranslogWriter create(
@@ -159,7 +175,8 @@ public static TranslogWriter create(
         final long primaryTerm,
         TragicExceptionHolder tragedy,
         final LongConsumer persistedSequenceNumberConsumer,
-        final BigArrays bigArrays
+        final BigArrays bigArrays,
+        Boolean remoteTranslogEnabled
     ) throws IOException {
         final Path checkpointFile = file.getParent().resolve(Translog.CHECKPOINT_FILE_NAME);
 
@@ -168,19 +185,25 @@ public static TranslogWriter create(
         try {
             checkpointChannel = channelFactory.open(checkpointFile, StandardOpenOption.WRITE);
             final TranslogHeader header = new TranslogHeader(translogUUID, primaryTerm);
-            header.write(channel);
+            header.write(channel, !Boolean.TRUE.equals(remoteTranslogEnabled));
+            TranslogCheckedContainer translogCheckedContainer = null;
+            if (Boolean.TRUE.equals(remoteTranslogEnabled)) {
+                ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+                header.write(byteArrayOutputStream);
+                translogCheckedContainer = new TranslogCheckedContainer(byteArrayOutputStream.toByteArray());
+            }
             final Checkpoint checkpoint = Checkpoint.emptyTranslogCheckpoint(
                 header.sizeInBytes(),
                 fileGeneration,
                 initialGlobalCheckpoint,
                 initialMinTranslogGen
             );
-            writeCheckpoint(checkpointChannel, checkpointFile, checkpoint);
+            writeCheckpoint(checkpointChannel, checkpointFile, checkpoint, remoteTranslogEnabled);
             final LongSupplier writerGlobalCheckpointSupplier;
             if (Assertions.ENABLED) {
                 writerGlobalCheckpointSupplier = () -> {
                     long gcp = globalCheckpointSupplier.getAsLong();
-                    assert gcp >= initialGlobalCheckpoint : "global checkpoint ["
+                    assert gcp >= initialGlobalCheckpoint || (remoteTranslogEnabled == Boolean.TRUE) : "global checkpoint ["
                         + gcp
                         + "] lower than initial gcp ["
                         + initialGlobalCheckpoint
@@ -203,7 +226,9 @@ public static TranslogWriter create(
                 header,
                 tragedy,
                 persistedSequenceNumberConsumer,
-                bigArrays
+                bigArrays,
+                translogCheckedContainer,
+                remoteTranslogEnabled
             );
         } catch (Exception exception) {
             // if we fail to bake the file-generation into the checkpoint we stick with the file and once we recover and that
@@ -354,9 +379,10 @@ synchronized boolean assertNoSeqAbove(long belowTerm, long aboveSeqNo) {
      *
      * Note: any exception during the sync process will be interpreted as a tragic exception and the writer will be closed before
      * raising the exception.
+     * @return  <code>true</code> if this call caused an actual sync operation
      */
-    public void sync() throws IOException {
-        syncUpTo(Long.MAX_VALUE);
+    public boolean sync() throws IOException {
+        return syncUpTo(Long.MAX_VALUE);
     }
 
     /**
@@ -426,7 +452,13 @@ public TranslogReader closeIntoReader() throws IOException {
                             closeWithTragicEvent(ex);
                             throw ex;
                         }
-                        return new TranslogReader(getLastSyncedCheckpoint(), channel, path, header);
+                        return new TranslogReader(
+                            getLastSyncedCheckpoint(),
+                            channel,
+                            path,
+                            header,
+                            (translogCheckedContainer != null) ? translogCheckedContainer.getChecksum() : null
+                        );
                     } else {
                         throw new AlreadyClosedException(
                             "translog [" + getGeneration() + "] is already closed (path [" + path + "]",
@@ -479,7 +511,7 @@ final boolean syncUpTo(long offset) throws IOException {
                     // double checked locking - we don't want to fsync unless we have to and now that we have
                     // the lock we should check again since if this code is busy we might have fsynced enough already
                     final Checkpoint checkpointToSync;
-                    final LongArrayList flushedSequenceNumbers;
+                    final List<Long> flushedSequenceNumbers;
                     final ReleasableBytesReference toWrite;
                     try (ReleasableLock toClose = writeLock.acquire()) {
                         synchronized (this) {
@@ -487,7 +519,7 @@ final boolean syncUpTo(long offset) throws IOException {
                             checkpointToSync = getCheckpoint();
                             toWrite = pollOpsToWrite();
                             flushedSequenceNumbers = nonFsyncedSequenceNumbers;
-                            nonFsyncedSequenceNumbers = new LongArrayList(64);
+                            nonFsyncedSequenceNumbers = new ArrayList<>(64);
                         }
 
                         try {
@@ -501,13 +533,15 @@ final boolean syncUpTo(long offset) throws IOException {
                     // now do the actual fsync outside of the synchronized block such that
                     // we can continue writing to the buffer etc.
                     try {
-                        channel.force(false);
-                        writeCheckpoint(checkpointChannel, checkpointPath, checkpointToSync);
+                        if (!Boolean.TRUE.equals(remoteTranslogEnabled)) {
+                            channel.force(false);
+                        }
+                        writeCheckpoint(checkpointChannel, checkpointPath, checkpointToSync, remoteTranslogEnabled);
                     } catch (final Exception ex) {
                         closeWithTragicEvent(ex);
                         throw ex;
                     }
-                    flushedSequenceNumbers.forEach((LongProcedure) persistedSequenceNumberConsumer::accept);
+                    flushedSequenceNumbers.forEach(persistedSequenceNumberConsumer::accept);
                     assert lastSyncedCheckpoint.offset <= checkpointToSync.offset : "illegal state: "
                         + lastSyncedCheckpoint.offset
                         + " <= "
@@ -557,6 +591,9 @@ private void writeAndReleaseOps(ReleasableBytesReference toWrite) throws IOExcep
                 while (currentBytesConsumed != current.length) {
                     int nBytesToWrite = Math.min(current.length - currentBytesConsumed, ioBuffer.remaining());
                     ioBuffer.put(current.bytes, current.offset + currentBytesConsumed, nBytesToWrite);
+                    if (translogCheckedContainer != null) {
+                        translogCheckedContainer.updateFromBytes(current.bytes, current.offset + currentBytesConsumed, nBytesToWrite);
+                    }
                     currentBytesConsumed += nBytesToWrite;
                     if (ioBuffer.hasRemaining() == false) {
                         ioBuffer.flip();
@@ -596,9 +633,13 @@ protected void readBytes(ByteBuffer targetBuffer, long position) throws IOExcept
         Channels.readFromFileChannelWithEofException(channel, position, targetBuffer);
     }
 
-    private static void writeCheckpoint(final FileChannel fileChannel, final Path checkpointFile, final Checkpoint checkpoint)
-        throws IOException {
-        Checkpoint.write(fileChannel, checkpointFile, checkpoint);
+    private static void writeCheckpoint(
+        final FileChannel fileChannel,
+        final Path checkpointFile,
+        final Checkpoint checkpoint,
+        final Boolean remoteTranslogEnabled
+    ) throws IOException {
+        Checkpoint.write(fileChannel, checkpointFile, checkpoint, !Boolean.TRUE.equals(remoteTranslogEnabled));
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/index/translog/TruncateTranslogAction.java b/server/src/main/java/org/opensearch/index/translog/TruncateTranslogAction.java
index 7d30fe2e2ffe3..25fcdc614172a 100644
--- a/server/src/main/java/org/opensearch/index/translog/TruncateTranslogAction.java
+++ b/server/src/main/java/org/opensearch/index/translog/TruncateTranslogAction.java
@@ -45,8 +45,8 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.seqno.SequenceNumbers;
@@ -67,6 +67,11 @@
 import java.util.Set;
 import java.util.TreeSet;
 
+/**
+ * Action event when translog is truncated
+ *
+ * @opensearch.internal
+ */
 public class TruncateTranslogAction {
 
     protected static final Logger logger = LogManager.getLogger(TruncateTranslogAction.class);
@@ -189,7 +194,8 @@ private boolean isTranslogClean(ShardPath shardPath, ClusterState clusterState,
                 shardPath.getShardId(),
                 translogPath,
                 indexSettings,
-                BigArrays.NON_RECYCLING_INSTANCE
+                BigArrays.NON_RECYCLING_INSTANCE,
+                ""
             );
             long primaryTerm = indexSettings.getIndexMetadata().primaryTerm(shardPath.getShardId().id());
             // We open translog to check for corruption, do not clean anything.
@@ -208,7 +214,7 @@ public long minTranslogGenRequired(List<TranslogReader> readers, TranslogWriter
                 }
             };
             try (
-                Translog translog = new Translog(
+                Translog translog = new LocalTranslog(
                     translogConfig,
                     translogUUID,
                     retainAllTranslogPolicy,
@@ -253,7 +259,7 @@ private static void writeEmptyCheckpoint(Path filename, int translogLength, long
     private static int writeEmptyTranslog(Path filename, String translogUUID) throws IOException {
         try (FileChannel fc = FileChannel.open(filename, StandardOpenOption.WRITE, StandardOpenOption.CREATE_NEW)) {
             TranslogHeader header = new TranslogHeader(translogUUID, SequenceNumbers.UNASSIGNED_PRIMARY_TERM);
-            header.write(fc);
+            header.write(fc, true);
             return header.sizeInBytes();
         }
     }
diff --git a/server/src/main/java/org/opensearch/index/translog/TruncatedTranslogException.java b/server/src/main/java/org/opensearch/index/translog/TruncatedTranslogException.java
index 8ae7a65727537..1b7f38e03817e 100644
--- a/server/src/main/java/org/opensearch/index/translog/TruncatedTranslogException.java
+++ b/server/src/main/java/org/opensearch/index/translog/TruncatedTranslogException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.index.translog;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is an error truncating the translog
+ *
+ * @opensearch.internal
+ */
 public class TruncatedTranslogException extends TranslogCorruptedException {
 
     public TruncatedTranslogException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/index/translog/WriteOnlyTranslogManager.java b/server/src/main/java/org/opensearch/index/translog/WriteOnlyTranslogManager.java
new file mode 100644
index 0000000000000..1b3892306920c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/WriteOnlyTranslogManager.java
@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.engine.LifecycleAware;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.translog.listener.TranslogEventListener;
+
+import java.io.IOException;
+import java.util.function.BooleanSupplier;
+import java.util.function.LongSupplier;
+import java.util.function.Supplier;
+
+/***
+ * The implementation of {@link TranslogManager} that only orchestrates writes to the underlying {@link Translog}
+ *
+ * @opensearch.internal
+ */
+public class WriteOnlyTranslogManager extends InternalTranslogManager {
+
+    public WriteOnlyTranslogManager(
+        TranslogConfig translogConfig,
+        LongSupplier primaryTermSupplier,
+        LongSupplier globalCheckpointSupplier,
+        TranslogDeletionPolicy translogDeletionPolicy,
+        ShardId shardId,
+        ReleasableLock readLock,
+        Supplier<LocalCheckpointTracker> localCheckpointTrackerSupplier,
+        String translogUUID,
+        TranslogEventListener translogEventListener,
+        LifecycleAware engineLifecycleAware,
+        TranslogFactory translogFactory,
+        BooleanSupplier primaryModeSupplier
+    ) throws IOException {
+        super(
+            translogConfig,
+            primaryTermSupplier,
+            globalCheckpointSupplier,
+            translogDeletionPolicy,
+            shardId,
+            readLock,
+            localCheckpointTrackerSupplier,
+            translogUUID,
+            translogEventListener,
+            engineLifecycleAware,
+            translogFactory,
+            primaryModeSupplier
+        );
+    }
+
+    @Override
+    public int restoreLocalHistoryFromTranslog(long processedCheckpoint, TranslogRecoveryRunner translogRecoveryRunner) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public int recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long localCheckpoint, long recoverUpToSeqNo)
+        throws IOException {
+        throw new UnsupportedOperationException("Read only replicas do not have an IndexWriter and cannot recover from a translog.");
+    }
+
+    @Override
+    public void skipTranslogRecovery() {
+        // Do nothing.
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/listener/CompositeTranslogEventListener.java b/server/src/main/java/org/opensearch/index/translog/listener/CompositeTranslogEventListener.java
new file mode 100644
index 0000000000000..9216616d5e9ab
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/listener/CompositeTranslogEventListener.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.listener;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.translog.TranslogException;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * The listener that multiplexes other {@link TranslogEventListener}
+ *
+ * @opensearch.internal
+ */
+public final class CompositeTranslogEventListener implements TranslogEventListener {
+
+    private final List<TranslogEventListener> listeners;
+    private final ShardId shardId;
+    private final Logger logger = LogManager.getLogger(CompositeTranslogEventListener.class);
+
+    public CompositeTranslogEventListener(Collection<TranslogEventListener> listeners, ShardId shardId) {
+        this.shardId = shardId;
+        for (TranslogEventListener listener : listeners) {
+            if (listener == null) {
+                throw new IllegalArgumentException("listeners must be non-null");
+            }
+        }
+        this.listeners = Collections.unmodifiableList(new ArrayList<>(listeners));
+    }
+
+    @Override
+    public void onAfterTranslogSync() {
+        List<Exception> exceptionList = new ArrayList<>(listeners.size());
+        for (TranslogEventListener listener : listeners) {
+            try {
+                listener.onAfterTranslogSync();
+            } catch (Exception ex) {
+                logger.warn(() -> new ParameterizedMessage("failed to invoke onTranslogSync listener"), ex);
+                exceptionList.add(ex);
+            }
+        }
+        maybeThrowTranslogExceptionAndSuppress(exceptionList);
+    }
+
+    @Override
+    public void onAfterTranslogRecovery() {
+        List<Exception> exceptionList = new ArrayList<>(listeners.size());
+        for (TranslogEventListener listener : listeners) {
+            try {
+                listener.onAfterTranslogRecovery();
+            } catch (Exception ex) {
+                logger.warn(() -> new ParameterizedMessage("failed to invoke onTranslogRecovery listener"), ex);
+                exceptionList.add(ex);
+            }
+        }
+        maybeThrowTranslogExceptionAndSuppress(exceptionList);
+    }
+
+    @Override
+    public void onBeginTranslogRecovery() {
+        List<Exception> exceptionList = new ArrayList<>(listeners.size());
+        for (TranslogEventListener listener : listeners) {
+            try {
+                listener.onBeginTranslogRecovery();
+            } catch (Exception ex) {
+                logger.warn(() -> new ParameterizedMessage("failed to invoke onBeginTranslogRecovery listener"), ex);
+                exceptionList.add(ex);
+            }
+        }
+        maybeThrowTranslogExceptionAndSuppress(exceptionList);
+    }
+
+    @Override
+    public void onFailure(String reason, Exception e) {
+        List<Exception> exceptionList = new ArrayList<>(listeners.size());
+        for (TranslogEventListener listener : listeners) {
+            try {
+                listener.onFailure(reason, e);
+            } catch (Exception ex) {
+                logger.warn(() -> new ParameterizedMessage("failed to invoke onFailure listener"), ex);
+                exceptionList.add(ex);
+            }
+        }
+        maybeThrowTranslogExceptionAndSuppress(exceptionList);
+    }
+
+    private <T extends Throwable> void maybeThrowTranslogExceptionAndSuppress(List<T> exceptions) {
+        T main = null;
+        for (T ex : exceptions) {
+            main = ExceptionsHelper.useOrSuppress(main, ex);
+        }
+        if (main != null) {
+            throw new TranslogException(shardId, "Error while executing translog event listener", main);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/listener/TranslogEventListener.java b/server/src/main/java/org/opensearch/index/translog/listener/TranslogEventListener.java
new file mode 100644
index 0000000000000..664cdd6c60985
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/listener/TranslogEventListener.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.listener;
+
+/**
+ * The listener that gets fired on events related to {@link org.opensearch.index.translog.TranslogManager}
+ *
+ * @opensearch.internal
+ */
+public interface TranslogEventListener {
+
+    TranslogEventListener NOOP_TRANSLOG_EVENT_LISTENER = new TranslogEventListener() {
+    };
+
+    /**
+     * Invoked after translog sync operations
+     */
+    default void onAfterTranslogSync() {}
+
+    /**
+     * Invoked after recovering operations from translog
+     */
+    default void onAfterTranslogRecovery() {}
+
+    /**
+     * Invoked before recovering operations from translog
+     */
+    default void onBeginTranslogRecovery() {}
+
+    /**
+     * Invoked when translog operations run into any other failure
+     * @param reason the failure reason
+     * @param ex the failure exception
+     */
+    default void onFailure(String reason, Exception ex) {}
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/listener/package-info.java b/server/src/main/java/org/opensearch/index/translog/listener/package-info.java
new file mode 100644
index 0000000000000..bfb2415881c10
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/listener/package-info.java
@@ -0,0 +1,11 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+/**
+ * Provides mechanism to listen into translog operations
+ */
+package org.opensearch.index.translog.listener;
diff --git a/server/src/main/java/org/opensearch/index/translog/package-info.java b/server/src/main/java/org/opensearch/index/translog/package-info.java
new file mode 100644
index 0000000000000..ba824031420ed
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all translog operations */
+package org.opensearch.index.translog;
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/BlobStoreTransferService.java b/server/src/main/java/org/opensearch/index/translog/transfer/BlobStoreTransferService.java
new file mode 100644
index 0000000000000..82dd6301ef79f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/BlobStoreTransferService.java
@@ -0,0 +1,236 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.ActionRunnable;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.RemoteTransferContainer;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeFileInputStream;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.translog.ChannelFactory;
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.channels.FileChannel;
+import java.nio.file.StandardOpenOption;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+import static org.opensearch.common.blobstore.BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC;
+
+/**
+ * Service that handles remote transfer of translog and checkpoint files
+ *
+ * @opensearch.internal
+ */
+public class BlobStoreTransferService implements TransferService {
+
+    private final BlobStore blobStore;
+    private final ThreadPool threadPool;
+
+    private static final Logger logger = LogManager.getLogger(BlobStoreTransferService.class);
+
+    public BlobStoreTransferService(BlobStore blobStore, ThreadPool threadPool) {
+        this.blobStore = blobStore;
+        this.threadPool = threadPool;
+    }
+
+    @Override
+    public void uploadBlob(
+        String threadPoolName,
+        final TransferFileSnapshot fileSnapshot,
+        Iterable<String> remoteTransferPath,
+        ActionListener<TransferFileSnapshot> listener,
+        WritePriority writePriority
+    ) {
+        assert remoteTransferPath instanceof BlobPath;
+        BlobPath blobPath = (BlobPath) remoteTransferPath;
+        threadPool.executor(threadPoolName).execute(ActionRunnable.wrap(listener, l -> {
+            try {
+                uploadBlob(fileSnapshot, blobPath, writePriority);
+                l.onResponse(fileSnapshot);
+            } catch (Exception e) {
+                logger.error(() -> new ParameterizedMessage("Failed to upload blob {}", fileSnapshot.getName()), e);
+                l.onFailure(new FileTransferException(fileSnapshot, e));
+            }
+        }));
+    }
+
+    @Override
+    public void uploadBlob(final TransferFileSnapshot fileSnapshot, Iterable<String> remoteTransferPath, WritePriority writePriority)
+        throws IOException {
+        BlobPath blobPath = (BlobPath) remoteTransferPath;
+        try (InputStream inputStream = fileSnapshot.inputStream()) {
+            blobStore.blobContainer(blobPath).writeBlobAtomic(fileSnapshot.getName(), inputStream, fileSnapshot.getContentLength(), true);
+        }
+    }
+
+    @Override
+    public void uploadBlobs(
+        Set<TransferFileSnapshot> fileSnapshots,
+        final Map<Long, BlobPath> blobPaths,
+        ActionListener<TransferFileSnapshot> listener,
+        WritePriority writePriority
+    ) {
+        fileSnapshots.forEach(fileSnapshot -> {
+            BlobPath blobPath = blobPaths.get(fileSnapshot.getPrimaryTerm());
+            if (!(blobStore.blobContainer(blobPath) instanceof AsyncMultiStreamBlobContainer)) {
+                uploadBlob(ThreadPool.Names.TRANSLOG_TRANSFER, fileSnapshot, blobPath, listener, writePriority);
+            } else {
+                uploadBlob(fileSnapshot, listener, blobPath, writePriority);
+            }
+        });
+
+    }
+
+    private void uploadBlob(
+        TransferFileSnapshot fileSnapshot,
+        ActionListener<TransferFileSnapshot> listener,
+        BlobPath blobPath,
+        WritePriority writePriority
+    ) {
+
+        try {
+            ChannelFactory channelFactory = FileChannel::open;
+            long contentLength;
+            try (FileChannel channel = channelFactory.open(fileSnapshot.getPath(), StandardOpenOption.READ)) {
+                contentLength = channel.size();
+            }
+            boolean remoteIntegrityEnabled = false;
+            BlobContainer blobContainer = blobStore.blobContainer(blobPath);
+            if (blobContainer instanceof AsyncMultiStreamBlobContainer) {
+                remoteIntegrityEnabled = ((AsyncMultiStreamBlobContainer) blobContainer).remoteIntegrityCheckSupported();
+            }
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                fileSnapshot.getName(),
+                fileSnapshot.getName(),
+                contentLength,
+                true,
+                writePriority,
+                (size, position) -> new OffsetRangeFileInputStream(fileSnapshot.getPath(), size, position),
+                Objects.requireNonNull(fileSnapshot.getChecksum()),
+                remoteIntegrityEnabled
+            );
+            ActionListener<Void> completionListener = ActionListener.wrap(resp -> listener.onResponse(fileSnapshot), ex -> {
+                logger.error(() -> new ParameterizedMessage("Failed to upload blob {}", fileSnapshot.getName()), ex);
+                listener.onFailure(new FileTransferException(fileSnapshot, ex));
+            });
+
+            completionListener = ActionListener.runBefore(completionListener, () -> {
+                try {
+                    remoteTransferContainer.close();
+                } catch (Exception e) {
+                    logger.warn("Error occurred while closing streams", e);
+                }
+            });
+
+            WriteContext writeContext = remoteTransferContainer.createWriteContext();
+            ((AsyncMultiStreamBlobContainer) blobStore.blobContainer(blobPath)).asyncBlobUpload(writeContext, completionListener);
+
+        } catch (Exception e) {
+            logger.error(() -> new ParameterizedMessage("Failed to upload blob {}", fileSnapshot.getName()), e);
+            listener.onFailure(new FileTransferException(fileSnapshot, e));
+        } finally {
+            try {
+                fileSnapshot.close();
+            } catch (IOException e) {
+                logger.warn("Error while closing TransferFileSnapshot", e);
+            }
+        }
+
+    }
+
+    @Override
+    public InputStream downloadBlob(Iterable<String> path, String fileName) throws IOException {
+        return blobStore.blobContainer((BlobPath) path).readBlob(fileName);
+    }
+
+    @Override
+    public void deleteBlobs(Iterable<String> path, List<String> fileNames) throws IOException {
+        blobStore.blobContainer((BlobPath) path).deleteBlobsIgnoringIfNotExists(fileNames);
+    }
+
+    @Override
+    public void deleteBlobsAsync(String threadpoolName, Iterable<String> path, List<String> fileNames, ActionListener<Void> listener) {
+        threadPool.executor(threadpoolName).execute(() -> {
+            try {
+                deleteBlobs(path, fileNames);
+                listener.onResponse(null);
+            } catch (IOException e) {
+                listener.onFailure(e);
+            }
+        });
+    }
+
+    @Override
+    public void delete(Iterable<String> path) throws IOException {
+        blobStore.blobContainer((BlobPath) path).delete();
+    }
+
+    @Override
+    public void deleteAsync(String threadpoolName, Iterable<String> path, ActionListener<Void> listener) {
+        threadPool.executor(threadpoolName).execute(() -> {
+            try {
+                delete(path);
+                listener.onResponse(null);
+            } catch (IOException e) {
+                listener.onFailure(e);
+            }
+        });
+    }
+
+    @Override
+    public Set<String> listAll(Iterable<String> path) throws IOException {
+        return blobStore.blobContainer((BlobPath) path).listBlobs().keySet();
+    }
+
+    @Override
+    public Set<String> listFolders(Iterable<String> path) throws IOException {
+        return blobStore.blobContainer((BlobPath) path).children().keySet();
+    }
+
+    @Override
+    public void listFoldersAsync(String threadpoolName, Iterable<String> path, ActionListener<Set<String>> listener) {
+        threadPool.executor(threadpoolName).execute(() -> {
+            try {
+                listener.onResponse(listFolders(path));
+            } catch (IOException e) {
+                listener.onFailure(e);
+            }
+        });
+    }
+
+    public void listAllInSortedOrder(Iterable<String> path, String filenamePrefix, int limit, ActionListener<List<BlobMetadata>> listener) {
+        blobStore.blobContainer((BlobPath) path).listBlobsByPrefixInSortedOrder(filenamePrefix, limit, LEXICOGRAPHIC, listener);
+    }
+
+    public void listAllInSortedOrderAsync(
+        String threadpoolName,
+        Iterable<String> path,
+        String filenamePrefix,
+        int limit,
+        ActionListener<List<BlobMetadata>> listener
+    ) {
+        threadPool.executor(threadpoolName).execute(() -> { listAllInSortedOrder(path, filenamePrefix, limit, listener); });
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/FileSnapshot.java b/server/src/main/java/org/opensearch/index/translog/transfer/FileSnapshot.java
new file mode 100644
index 0000000000000..dcec94edd694f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/FileSnapshot.java
@@ -0,0 +1,226 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.lucene.store.InputStreamIndexInput;
+import org.opensearch.common.util.io.IOUtils;
+
+import java.io.BufferedInputStream;
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.channels.Channels;
+import java.nio.channels.FileChannel;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.Arrays;
+import java.util.Objects;
+
+/**
+ * Snapshot of a single file that gets transferred
+ *
+ * @opensearch.internal
+ */
+public class FileSnapshot implements Closeable {
+
+    private final String name;
+    @Nullable
+    private final FileChannel fileChannel;
+    @Nullable
+    private Path path;
+    @Nullable
+    private byte[] content;
+
+    private FileSnapshot(Path path) throws IOException {
+        Objects.requireNonNull(path);
+        this.name = path.getFileName().toString();
+        this.path = path;
+        this.fileChannel = FileChannel.open(path, StandardOpenOption.READ);
+    }
+
+    private FileSnapshot(String name, byte[] content) {
+        Objects.requireNonNull(name);
+        this.name = name;
+        this.content = content;
+        this.fileChannel = null;
+    }
+
+    public Path getPath() {
+        return path;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public long getContentLength() throws IOException {
+        return fileChannel == null ? content.length : fileChannel.size();
+    }
+
+    public InputStream inputStream() throws IOException {
+        return fileChannel != null
+            ? new BufferedInputStream(Channels.newInputStream(fileChannel))
+            : new InputStreamIndexInput(new ByteArrayIndexInput(this.name, content), content.length);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, content, path);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        FileSnapshot other = (FileSnapshot) o;
+        return Objects.equals(this.name, other.name) && Arrays.equals(this.content, other.content) && Objects.equals(this.path, other.path);
+    }
+
+    @Override
+    public String toString() {
+        return new StringBuilder("FileInfo [").append(" name = ")
+            .append(name)
+            .append(", path = ")
+            .append(path.toUri())
+            .append("]")
+            .toString();
+    }
+
+    @Override
+    public void close() throws IOException {
+        IOUtils.close(fileChannel);
+    }
+
+    /**
+     * Snapshot of a single file with primary term that gets transferred
+     *
+     * @opensearch.internal
+     */
+    public static class TransferFileSnapshot extends FileSnapshot {
+
+        private final long primaryTerm;
+        private Long checksum;
+
+        public TransferFileSnapshot(Path path, long primaryTerm, Long checksum) throws IOException {
+            super(path);
+            this.primaryTerm = primaryTerm;
+            this.checksum = checksum;
+        }
+
+        public TransferFileSnapshot(String name, byte[] content, long primaryTerm) throws IOException {
+            super(name, content);
+            this.primaryTerm = primaryTerm;
+        }
+
+        public Long getChecksum() {
+            return checksum;
+        }
+
+        public long getPrimaryTerm() {
+            return primaryTerm;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(primaryTerm, super.hashCode());
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (super.equals(o)) {
+                if (this == o) return true;
+                if (getClass() != o.getClass()) return false;
+                TransferFileSnapshot other = (TransferFileSnapshot) o;
+                return Objects.equals(this.primaryTerm, other.primaryTerm);
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Snapshot of a single .tlg file that gets transferred
+     *
+     * @opensearch.internal
+     */
+    public static final class TranslogFileSnapshot extends TransferFileSnapshot {
+
+        private final long generation;
+
+        public TranslogFileSnapshot(long primaryTerm, long generation, Path path, Long checksum) throws IOException {
+            super(path, primaryTerm, checksum);
+            this.generation = generation;
+        }
+
+        public long getGeneration() {
+            return generation;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(generation, super.hashCode());
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (super.equals(o)) {
+                if (this == o) return true;
+                if (getClass() != o.getClass()) return false;
+                TranslogFileSnapshot other = (TranslogFileSnapshot) o;
+                return Objects.equals(this.generation, other.generation);
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Snapshot of a single .ckp file that gets transferred
+     *
+     * @opensearch.internal
+     */
+    public static final class CheckpointFileSnapshot extends TransferFileSnapshot {
+
+        private final long generation;
+
+        private final long minTranslogGeneration;
+
+        public CheckpointFileSnapshot(long primaryTerm, long generation, long minTranslogGeneration, Path path, Long checksum)
+            throws IOException {
+            super(path, primaryTerm, checksum);
+            this.minTranslogGeneration = minTranslogGeneration;
+            this.generation = generation;
+        }
+
+        public long getGeneration() {
+            return generation;
+        }
+
+        public long getMinTranslogGeneration() {
+            return minTranslogGeneration;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(generation, minTranslogGeneration, super.hashCode());
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (super.equals(o)) {
+                if (this == o) return true;
+                if (getClass() != o.getClass()) return false;
+                CheckpointFileSnapshot other = (CheckpointFileSnapshot) o;
+                return Objects.equals(this.minTranslogGeneration, other.minTranslogGeneration)
+                    && Objects.equals(this.generation, other.generation);
+            }
+            return false;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferException.java b/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferException.java
new file mode 100644
index 0000000000000..89a4135d2409b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferException.java
@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+
+/**
+ * Exception when a single file transfer encounters a failure
+ *
+ * @opensearch.internal
+ */
+public class FileTransferException extends RuntimeException {
+
+    private final TransferFileSnapshot fileSnapshot;
+
+    public FileTransferException(TransferFileSnapshot fileSnapshot, Throwable cause) {
+        super(cause);
+        this.fileSnapshot = fileSnapshot;
+    }
+
+    public TransferFileSnapshot getFileSnapshot() {
+        return fileSnapshot;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferTracker.java b/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferTracker.java
new file mode 100644
index 0000000000000..9c2304f809f46
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/FileTransferTracker.java
@@ -0,0 +1,138 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import org.opensearch.index.translog.transfer.listener.FileTransferListener;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
+
+/**
+ * FileTransferTracker keeps track of translog files uploaded to the remote translog
+ */
+public class FileTransferTracker implements FileTransferListener {
+
+    private final ConcurrentHashMap<String, TransferState> fileTransferTracker;
+    private final ShardId shardId;
+    private final RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+    private Map<String, Long> bytesForTlogCkpFileToUpload;
+    private long fileTransferStartTime = -1;
+
+    public FileTransferTracker(ShardId shardId, RemoteTranslogTransferTracker remoteTranslogTransferTracker) {
+        this.shardId = shardId;
+        this.fileTransferTracker = new ConcurrentHashMap<>();
+        this.remoteTranslogTransferTracker = remoteTranslogTransferTracker;
+    }
+
+    void recordFileTransferStartTime(long uploadStartTime) {
+        // Recording the start time more than once for a sync is invalid
+        if (fileTransferStartTime == -1) {
+            fileTransferStartTime = uploadStartTime;
+        }
+    }
+
+    void recordBytesForFiles(Set<TransferFileSnapshot> toUpload) {
+        bytesForTlogCkpFileToUpload = new HashMap<>();
+        toUpload.forEach(file -> {
+            try {
+                bytesForTlogCkpFileToUpload.put(file.getName(), file.getContentLength());
+            } catch (IOException ignored) {
+                bytesForTlogCkpFileToUpload.put(file.getName(), 0L);
+            }
+        });
+    }
+
+    long getTotalBytesToUpload() {
+        return bytesForTlogCkpFileToUpload.values().stream().reduce(0L, Long::sum);
+    }
+
+    @Override
+    public void onSuccess(TransferFileSnapshot fileSnapshot) {
+        long durationInMillis = (System.nanoTime() - fileTransferStartTime) / 1_000_000L;
+        remoteTranslogTransferTracker.addUploadTimeInMillis(durationInMillis);
+        remoteTranslogTransferTracker.addUploadBytesSucceeded(bytesForTlogCkpFileToUpload.get(fileSnapshot.getName()));
+        add(fileSnapshot.getName(), TransferState.SUCCESS);
+    }
+
+    void add(String file, boolean success) {
+        TransferState targetState = success ? TransferState.SUCCESS : TransferState.FAILED;
+        add(file, targetState);
+    }
+
+    private void add(String file, TransferState targetState) {
+        fileTransferTracker.compute(file, (k, v) -> {
+            if (v == null || v.validateNextState(targetState)) {
+                return targetState;
+            }
+            throw new IllegalStateException("Unexpected transfer state " + v + "while setting target to" + targetState);
+        });
+    }
+
+    @Override
+    public void onFailure(TransferFileSnapshot fileSnapshot, Exception e) {
+        long durationInMillis = (System.nanoTime() - fileTransferStartTime) / 1_000_000L;
+        remoteTranslogTransferTracker.addUploadTimeInMillis(durationInMillis);
+        remoteTranslogTransferTracker.addUploadBytesFailed(bytesForTlogCkpFileToUpload.get(fileSnapshot.getName()));
+        add(fileSnapshot.getName(), TransferState.FAILED);
+    }
+
+    public void delete(List<String> names) {
+        for (String name : names) {
+            fileTransferTracker.remove(name);
+        }
+    }
+
+    public boolean uploaded(String file) {
+        return fileTransferTracker.get(file) == TransferState.SUCCESS;
+    }
+
+    public Set<TransferFileSnapshot> exclusionFilter(Set<TransferFileSnapshot> original) {
+        return original.stream()
+            .filter(fileSnapshot -> fileTransferTracker.get(fileSnapshot.getName()) != TransferState.SUCCESS)
+            .collect(Collectors.toSet());
+    }
+
+    public Set<String> allUploaded() {
+        Set<String> successFileTransferTracker = new HashSet<>();
+        fileTransferTracker.forEach((k, v) -> {
+            if (v == TransferState.SUCCESS) {
+                successFileTransferTracker.add(k);
+            }
+        });
+        return successFileTransferTracker;
+    }
+
+    /**
+     * Represents the state of the upload operation
+     */
+    private enum TransferState {
+        SUCCESS,
+        FAILED;
+
+        public boolean validateNextState(TransferState target) {
+            switch (this) {
+                case FAILED:
+                    return true;
+                case SUCCESS:
+                    return Objects.equals(SUCCESS, target);
+            }
+            return false;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TransferService.java b/server/src/main/java/org/opensearch/index/translog/transfer/TransferService.java
new file mode 100644
index 0000000000000..cfe833dde87eb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TransferService.java
@@ -0,0 +1,138 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Interface for the translog transfer service responsible for interacting with a remote store
+ *
+ * @opensearch.internal
+ */
+public interface TransferService {
+
+    /**
+     * Uploads the {@link TransferFileSnapshot} async, once the upload is complete the callback is invoked
+     * @param threadPoolName threadpool type which will be used to upload blobs asynchronously
+     * @param fileSnapshot the file snapshot to upload
+     * @param remotePath the remote path where upload should be made
+     * @param listener the callback to be invoked once upload completes successfully/fails
+     */
+    void uploadBlob(
+        String threadPoolName,
+        final TransferFileSnapshot fileSnapshot,
+        Iterable<String> remotePath,
+        ActionListener<TransferFileSnapshot> listener,
+        WritePriority writePriority
+    );
+
+    /**
+     * Uploads multiple {@link TransferFileSnapshot}, once the upload is complete the callback is invoked
+     * @param fileSnapshots the file snapshots to upload
+     * @param blobPaths Primary term to {@link BlobPath} map
+     * @param listener the callback to be invoked once uploads complete successfully/fail
+     */
+    void uploadBlobs(
+        Set<TransferFileSnapshot> fileSnapshots,
+        final Map<Long, BlobPath> blobPaths,
+        ActionListener<TransferFileSnapshot> listener,
+        WritePriority writePriority
+    ) throws Exception;
+
+    /**
+     * Uploads the {@link TransferFileSnapshot} blob
+     * @param fileSnapshot the file snapshot to upload
+     * @param remotePath the remote path where upload should be made
+     * @param writePriority Priority by which content needs to be written.
+     * @throws IOException the exception while transferring the data
+     */
+    void uploadBlob(final TransferFileSnapshot fileSnapshot, Iterable<String> remotePath, WritePriority writePriority) throws IOException;
+
+    void deleteBlobs(Iterable<String> path, List<String> fileNames) throws IOException;
+
+    /**
+     * Deletes the list of files in async and uses the listener to propagate success or failure.
+     * @param threadpoolName threadpool type which will be used to perform the deletion asynchronously.
+     * @param path the path where the deletion would occur on remote store.
+     * @param fileNames list of all files that are to be deleted within the path.
+     * @param listener the callback to be invoked once delete completes successfully/fails.
+     */
+    void deleteBlobsAsync(String threadpoolName, Iterable<String> path, List<String> fileNames, ActionListener<Void> listener);
+
+    /**
+     *  Deletes all contents with-in a path.
+     * @param path the path in remote which needs to be deleted completely.
+     * @throws IOException the exception while transferring the data.
+     */
+    void delete(Iterable<String> path) throws IOException;
+
+    /**
+     * Deletes all contents with-in a path and invokes the listener on success or failure.
+     *
+     * @param threadpoolName threadpool type which will be used to perform the deletion asynchronously.
+     * @param path           path in remote store.
+     * @param listener       the callback to be invoked once delete completes successfully/fails.
+     */
+    void deleteAsync(String threadpoolName, Iterable<String> path, ActionListener<Void> listener);
+
+    /**
+     * Lists the files
+     * @param path : the path to list
+     * @return : the lists of files
+     * @throws IOException the exception while listing the path
+     */
+    Set<String> listAll(Iterable<String> path) throws IOException;
+
+    /**
+     * Lists the folders inside the path.
+     * @param path : the path
+     * @return list of folders inside the path
+     * @throws IOException the exception while listing folders inside the path
+     */
+    Set<String> listFolders(Iterable<String> path) throws IOException;
+
+    /**
+     * Invokes the listener with the list of folders inside the path. For exception, invokes the {@code listener.onFailure}.
+     *
+     * @param threadpoolName threadpool type which will be used to perform the deletion asynchronously.
+     * @param path           path in remote store
+     * @param listener       the callback to be invoked once list folders succeeds or fails.
+     */
+    void listFoldersAsync(String threadpoolName, Iterable<String> path, ActionListener<Set<String>> listener);
+
+    /**
+     *
+     * @param path  the remote path from where download should be made
+     * @param fileName the name of the file
+     * @return inputstream of the remote file
+     * @throws IOException the exception while reading the data
+     */
+    InputStream downloadBlob(Iterable<String> path, String fileName) throws IOException;
+
+    void listAllInSortedOrder(Iterable<String> path, String filenamePrefix, int limit, ActionListener<List<BlobMetadata>> listener);
+
+    void listAllInSortedOrderAsync(
+        String threadpoolName,
+        Iterable<String> path,
+        String filenamePrefix,
+        int limit,
+        ActionListener<List<BlobMetadata>> listener
+    );
+
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TransferSnapshot.java b/server/src/main/java/org/opensearch/index/translog/transfer/TransferSnapshot.java
new file mode 100644
index 0000000000000..ef34fd31a296b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TransferSnapshot.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.index.translog.transfer.FileSnapshot.CheckpointFileSnapshot;
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import org.opensearch.index.translog.transfer.FileSnapshot.TranslogFileSnapshot;
+
+import java.util.Set;
+
+/**
+ * The snapshot of the generational translog and checkpoint files and it's corresponding metadata that is transferred
+ * to the {@link TransferService}
+ *
+ * @opensearch.internal
+ */
+public interface TransferSnapshot {
+
+    /**
+     * The snapshot of the checkpoint generational files
+     * @return the set of {@link CheckpointFileSnapshot}
+     */
+    Set<TransferFileSnapshot> getCheckpointFileSnapshots();
+
+    /**
+     * The snapshot of the translog generational files
+     * @return the set of {@link TranslogFileSnapshot}
+     */
+    Set<TransferFileSnapshot> getTranslogFileSnapshots();
+
+    /**
+     * The translog transfer metadata of this {@link TransferSnapshot}
+     * @return the translog transfer metadata
+     */
+    TranslogTransferMetadata getTranslogTransferMetadata();
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogCheckpointTransferSnapshot.java b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogCheckpointTransferSnapshot.java
new file mode 100644
index 0000000000000..fb78731246a07
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogCheckpointTransferSnapshot.java
@@ -0,0 +1,191 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.index.translog.TranslogReader;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.LongStream;
+
+import static org.opensearch.index.translog.transfer.FileSnapshot.CheckpointFileSnapshot;
+import static org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import static org.opensearch.index.translog.transfer.FileSnapshot.TranslogFileSnapshot;
+
+/**
+ * Implementation for a {@link TransferSnapshot} which builds the snapshot from the translog and checkpoint files present on the local-disk
+ *
+ * @opensearch.internal
+ */
+public class TranslogCheckpointTransferSnapshot implements TransferSnapshot, Closeable {
+
+    private final Set<Tuple<TranslogFileSnapshot, CheckpointFileSnapshot>> translogCheckpointFileInfoTupleSet;
+    private final int size;
+    private final long generation;
+    private final long primaryTerm;
+    private long minTranslogGeneration;
+
+    private String nodeId;
+
+    TranslogCheckpointTransferSnapshot(long primaryTerm, long generation, int size, String nodeId) {
+        translogCheckpointFileInfoTupleSet = new HashSet<>(size);
+        this.size = size;
+        this.generation = generation;
+        this.primaryTerm = primaryTerm;
+        this.nodeId = nodeId;
+    }
+
+    private void add(TranslogFileSnapshot translogFileSnapshot, CheckpointFileSnapshot checkPointFileSnapshot) {
+        translogCheckpointFileInfoTupleSet.add(Tuple.tuple(translogFileSnapshot, checkPointFileSnapshot));
+        assert translogFileSnapshot.getGeneration() == checkPointFileSnapshot.getGeneration();
+    }
+
+    private void setMinTranslogGeneration(long minTranslogGeneration) {
+        this.minTranslogGeneration = minTranslogGeneration;
+    }
+
+    @Override
+    public Set<TransferFileSnapshot> getTranslogFileSnapshots() {
+        return translogCheckpointFileInfoTupleSet.stream().map(Tuple::v1).collect(Collectors.toSet());
+    }
+
+    @Override
+    public TranslogTransferMetadata getTranslogTransferMetadata() {
+        return new TranslogTransferMetadata(
+            primaryTerm,
+            generation,
+            minTranslogGeneration,
+            translogCheckpointFileInfoTupleSet.size() * 2,
+            nodeId
+        );
+    }
+
+    @Override
+    public Set<TransferFileSnapshot> getCheckpointFileSnapshots() {
+        return translogCheckpointFileInfoTupleSet.stream().map(Tuple::v2).collect(Collectors.toSet());
+    }
+
+    public void close() throws IOException {
+        List<Exception> exceptionList = new ArrayList<>();
+        Set<FileSnapshot.TransferFileSnapshot> fileSnapshots = getTranslogFileSnapshots();
+        fileSnapshots.addAll(getCheckpointFileSnapshots());
+
+        for (FileSnapshot fileSnapshot : fileSnapshots) {
+            try {
+                fileSnapshot.close();
+            } catch (IOException e) {
+                exceptionList.add(e);
+            }
+        }
+
+        if (!exceptionList.isEmpty()) {
+            IOException ex = new IOException("IO Exception while closing file snapshots");
+            exceptionList.forEach(ex::addSuppressed);
+            throw ex;
+        }
+    }
+
+    @Override
+    public String toString() {
+        return new StringBuilder("TranslogTransferSnapshot [").append(" primary term = ")
+            .append(primaryTerm)
+            .append(", generation = ")
+            .append(generation)
+            .append(" ]")
+            .toString();
+    }
+
+    /**
+     * Builder for {@link TranslogCheckpointTransferSnapshot}
+     */
+    public static class Builder {
+        private final long primaryTerm;
+        private final long generation;
+        private final List<TranslogReader> readers;
+        private final Function<Long, String> checkpointGenFileNameMapper;
+        private final Path location;
+        private final String nodeId;
+
+        public Builder(
+            long primaryTerm,
+            long generation,
+            Path location,
+            List<TranslogReader> readers,
+            Function<Long, String> checkpointGenFileNameMapper,
+            String nodeId
+        ) {
+            this.primaryTerm = primaryTerm;
+            this.generation = generation;
+            this.readers = readers;
+            this.checkpointGenFileNameMapper = checkpointGenFileNameMapper;
+            this.location = location;
+            this.nodeId = nodeId;
+        }
+
+        public TranslogCheckpointTransferSnapshot build() throws IOException {
+            final List<Long> generations = new LinkedList<>();
+            long highestGeneration = Long.MIN_VALUE;
+            long highestGenPrimaryTerm = Long.MIN_VALUE;
+            long lowestGeneration = Long.MAX_VALUE;
+            long highestGenMinTranslogGeneration = Long.MIN_VALUE;
+            TranslogCheckpointTransferSnapshot translogTransferSnapshot = new TranslogCheckpointTransferSnapshot(
+                primaryTerm,
+                generation,
+                readers.size(),
+                nodeId
+            );
+            for (TranslogReader reader : readers) {
+                final long readerGeneration = reader.getGeneration();
+                final long readerPrimaryTerm = reader.getPrimaryTerm();
+                final long minTranslogGeneration = reader.getCheckpoint().getMinTranslogGeneration();
+                final long checkpointGeneration = reader.getCheckpoint().getGeneration();
+                Path translogPath = reader.path();
+                Path checkpointPath = location.resolve(checkpointGenFileNameMapper.apply(readerGeneration));
+                generations.add(readerGeneration);
+                translogTransferSnapshot.add(
+                    new TranslogFileSnapshot(readerPrimaryTerm, readerGeneration, translogPath, reader.getTranslogChecksum()),
+                    new CheckpointFileSnapshot(
+                        readerPrimaryTerm,
+                        checkpointGeneration,
+                        minTranslogGeneration,
+                        checkpointPath,
+                        reader.getCheckpointChecksum()
+                    )
+                );
+                if (readerGeneration > highestGeneration) {
+                    highestGeneration = readerGeneration;
+                    highestGenMinTranslogGeneration = minTranslogGeneration;
+                    highestGenPrimaryTerm = readerPrimaryTerm;
+                }
+                lowestGeneration = Math.min(lowestGeneration, readerGeneration);
+            }
+            translogTransferSnapshot.setMinTranslogGeneration(highestGenMinTranslogGeneration);
+
+            assert this.primaryTerm == highestGenPrimaryTerm : "inconsistent primary term";
+            assert this.generation == highestGeneration : " inconsistent generation ";
+            final long finalHighestGeneration = highestGeneration;
+            assert LongStream.iterate(lowestGeneration, i -> i + 1)
+                .limit(highestGeneration)
+                .filter(l -> (l <= finalHighestGeneration))
+                .boxed()
+                .collect(Collectors.toList())
+                .equals(generations.stream().sorted().collect(Collectors.toList())) == true : "generation gaps found";
+            return translogTransferSnapshot;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferManager.java b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferManager.java
new file mode 100644
index 0000000000000..d988b8a6254ff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferManager.java
@@ -0,0 +1,578 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.io.VersionedCodecStreamWrapper;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.transfer.listener.TranslogTransferListener;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import static org.opensearch.index.translog.transfer.FileSnapshot.TranslogFileSnapshot;
+
+/**
+ * The class responsible for orchestrating the transfer of a {@link TransferSnapshot} via a {@link TransferService}
+ *
+ * @opensearch.internal
+ */
+public class TranslogTransferManager {
+
+    private final ShardId shardId;
+    private final TransferService transferService;
+    private final BlobPath remoteDataTransferPath;
+    private final BlobPath remoteMetadataTransferPath;
+    private final BlobPath remoteBaseTransferPath;
+    private final FileTransferTracker fileTransferTracker;
+    private final RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+
+    private static final long TRANSFER_TIMEOUT_IN_MILLIS = 30000;
+
+    private static final int METADATA_FILES_TO_FETCH = 10;
+
+    private final Logger logger;
+    private final static String METADATA_DIR = "metadata";
+    private final static String DATA_DIR = "data";
+
+    private static final VersionedCodecStreamWrapper<TranslogTransferMetadata> metadataStreamWrapper = new VersionedCodecStreamWrapper<>(
+        new TranslogTransferMetadataHandler(),
+        TranslogTransferMetadata.CURRENT_VERSION,
+        TranslogTransferMetadata.METADATA_CODEC
+    );
+
+    public TranslogTransferManager(
+        ShardId shardId,
+        TransferService transferService,
+        BlobPath remoteBaseTransferPath,
+        FileTransferTracker fileTransferTracker,
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker
+    ) {
+        this.shardId = shardId;
+        this.transferService = transferService;
+        this.remoteBaseTransferPath = remoteBaseTransferPath;
+        this.remoteDataTransferPath = remoteBaseTransferPath.add(DATA_DIR);
+        this.remoteMetadataTransferPath = remoteBaseTransferPath.add(METADATA_DIR);
+        this.fileTransferTracker = fileTransferTracker;
+        this.logger = Loggers.getLogger(getClass(), shardId);
+        this.remoteTranslogTransferTracker = remoteTranslogTransferTracker;
+    }
+
+    public RemoteTranslogTransferTracker getRemoteTranslogTransferTracker() {
+        return remoteTranslogTransferTracker;
+    }
+
+    public ShardId getShardId() {
+        return this.shardId;
+    }
+
+    public boolean transferSnapshot(TransferSnapshot transferSnapshot, TranslogTransferListener translogTransferListener)
+        throws IOException {
+        List<Exception> exceptionList = new ArrayList<>(transferSnapshot.getTranslogTransferMetadata().getCount());
+        Set<TransferFileSnapshot> toUpload = new HashSet<>(transferSnapshot.getTranslogTransferMetadata().getCount());
+        long metadataBytesToUpload;
+        long metadataUploadStartTime;
+        long uploadStartTime;
+        long prevUploadBytesSucceeded = remoteTranslogTransferTracker.getUploadBytesSucceeded();
+        long prevUploadTimeInMillis = remoteTranslogTransferTracker.getTotalUploadTimeInMillis();
+
+        try {
+            toUpload.addAll(fileTransferTracker.exclusionFilter(transferSnapshot.getTranslogFileSnapshots()));
+            toUpload.addAll(fileTransferTracker.exclusionFilter((transferSnapshot.getCheckpointFileSnapshots())));
+            if (toUpload.isEmpty()) {
+                logger.trace("Nothing to upload for transfer");
+                return true;
+            }
+
+            fileTransferTracker.recordBytesForFiles(toUpload);
+            captureStatsBeforeUpload();
+            final CountDownLatch latch = new CountDownLatch(toUpload.size());
+            LatchedActionListener<TransferFileSnapshot> latchedActionListener = new LatchedActionListener<>(
+                ActionListener.wrap(fileTransferTracker::onSuccess, ex -> {
+                    assert ex instanceof FileTransferException;
+                    logger.error(
+                        () -> new ParameterizedMessage(
+                            "Exception during transfer for file {}",
+                            ((FileTransferException) ex).getFileSnapshot().getName()
+                        ),
+                        ex
+                    );
+                    FileTransferException e = (FileTransferException) ex;
+                    TransferFileSnapshot file = e.getFileSnapshot();
+                    fileTransferTracker.onFailure(file, ex);
+                    exceptionList.add(ex);
+                }),
+                latch
+            );
+            Map<Long, BlobPath> blobPathMap = new HashMap<>();
+            toUpload.forEach(
+                fileSnapshot -> blobPathMap.put(
+                    fileSnapshot.getPrimaryTerm(),
+                    remoteDataTransferPath.add(String.valueOf(fileSnapshot.getPrimaryTerm()))
+                )
+            );
+
+            uploadStartTime = System.nanoTime();
+            // TODO: Ideally each file's upload start time should be when it is actually picked for upload
+            // https://github.com/opensearch-project/OpenSearch/issues/9729
+            fileTransferTracker.recordFileTransferStartTime(uploadStartTime);
+            transferService.uploadBlobs(toUpload, blobPathMap, latchedActionListener, WritePriority.HIGH);
+
+            try {
+                if (latch.await(TRANSFER_TIMEOUT_IN_MILLIS, TimeUnit.MILLISECONDS) == false) {
+                    Exception ex = new TimeoutException("Timed out waiting for transfer of snapshot " + transferSnapshot + " to complete");
+                    exceptionList.forEach(ex::addSuppressed);
+                    throw ex;
+                }
+            } catch (InterruptedException ex) {
+                exceptionList.forEach(ex::addSuppressed);
+                Thread.currentThread().interrupt();
+                throw ex;
+            }
+            if (exceptionList.isEmpty()) {
+                TransferFileSnapshot tlogMetadata = prepareMetadata(transferSnapshot);
+                metadataBytesToUpload = tlogMetadata.getContentLength();
+                remoteTranslogTransferTracker.addUploadBytesStarted(metadataBytesToUpload);
+                metadataUploadStartTime = System.nanoTime();
+                try {
+                    transferService.uploadBlob(tlogMetadata, remoteMetadataTransferPath, WritePriority.HIGH);
+                } catch (Exception exception) {
+                    remoteTranslogTransferTracker.addUploadTimeInMillis((System.nanoTime() - metadataUploadStartTime) / 1_000_000L);
+                    remoteTranslogTransferTracker.addUploadBytesFailed(metadataBytesToUpload);
+                    // outer catch handles capturing stats on upload failure
+                    throw exception;
+                }
+
+                remoteTranslogTransferTracker.addUploadTimeInMillis((System.nanoTime() - metadataUploadStartTime) / 1_000_000L);
+                remoteTranslogTransferTracker.addUploadBytesSucceeded(metadataBytesToUpload);
+                captureStatsOnUploadSuccess(prevUploadBytesSucceeded, prevUploadTimeInMillis);
+                translogTransferListener.onUploadComplete(transferSnapshot);
+                return true;
+            } else {
+                Exception ex = new IOException("Failed to upload " + exceptionList.size() + " files during transfer");
+                exceptionList.forEach(ex::addSuppressed);
+                throw ex;
+            }
+        } catch (Exception ex) {
+            logger.error(() -> new ParameterizedMessage("Transfer failed for snapshot {}", transferSnapshot), ex);
+            captureStatsOnUploadFailure();
+            translogTransferListener.onUploadFailed(transferSnapshot, ex);
+            return false;
+        }
+    }
+
+    /**
+     * Adds relevant stats to the tracker when an upload is started
+     */
+    private void captureStatsBeforeUpload() {
+        remoteTranslogTransferTracker.incrementTotalUploadsStarted();
+        // TODO: Ideally each file's byte uploads started should be when it is actually picked for upload
+        // https://github.com/opensearch-project/OpenSearch/issues/9729
+        remoteTranslogTransferTracker.addUploadBytesStarted(fileTransferTracker.getTotalBytesToUpload());
+    }
+
+    /**
+     * Adds relevant stats to the tracker when an upload is successfully completed
+     */
+    private void captureStatsOnUploadSuccess(long prevUploadBytesSucceeded, long prevUploadTimeInMillis) {
+        remoteTranslogTransferTracker.setLastSuccessfulUploadTimestamp(System.currentTimeMillis());
+        remoteTranslogTransferTracker.incrementTotalUploadsSucceeded();
+        long totalUploadedBytes = remoteTranslogTransferTracker.getUploadBytesSucceeded() - prevUploadBytesSucceeded;
+        remoteTranslogTransferTracker.updateUploadBytesMovingAverage(totalUploadedBytes);
+        long uploadDurationInMillis = remoteTranslogTransferTracker.getTotalUploadTimeInMillis() - prevUploadTimeInMillis;
+        remoteTranslogTransferTracker.updateUploadTimeMovingAverage(uploadDurationInMillis);
+        if (uploadDurationInMillis > 0) {
+            remoteTranslogTransferTracker.updateUploadBytesPerSecMovingAverage((totalUploadedBytes * 1_000L) / uploadDurationInMillis);
+        }
+    }
+
+    /**
+     * Adds relevant stats to the tracker when an upload has failed
+     */
+    private void captureStatsOnUploadFailure() {
+        remoteTranslogTransferTracker.incrementTotalUploadsFailed();
+    }
+
+    public boolean downloadTranslog(String primaryTerm, String generation, Path location) throws IOException {
+        logger.trace(
+            "Downloading translog files with: Primary Term = {}, Generation = {}, Location = {}",
+            primaryTerm,
+            generation,
+            location
+        );
+        // Download Checkpoint file from remote to local FS
+        String ckpFileName = Translog.getCommitCheckpointFileName(Long.parseLong(generation));
+        downloadToFS(ckpFileName, location, primaryTerm);
+        // Download translog file from remote to local FS
+        String translogFilename = Translog.getFilename(Long.parseLong(generation));
+        downloadToFS(translogFilename, location, primaryTerm);
+        return true;
+    }
+
+    private void downloadToFS(String fileName, Path location, String primaryTerm) throws IOException {
+        Path filePath = location.resolve(fileName);
+        // Here, we always override the existing file if present.
+        // We need to change this logic when we introduce incremental download
+        if (Files.exists(filePath)) {
+            Files.delete(filePath);
+        }
+
+        boolean downloadStatus = false;
+        long bytesToRead = 0, downloadStartTime = System.nanoTime();
+        try (InputStream inputStream = transferService.downloadBlob(remoteDataTransferPath.add(primaryTerm), fileName)) {
+            // Capture number of bytes for stats before reading
+            bytesToRead = inputStream.available();
+            Files.copy(inputStream, filePath);
+            downloadStatus = true;
+        } finally {
+            remoteTranslogTransferTracker.addDownloadTimeInMillis((System.nanoTime() - downloadStartTime) / 1_000_000L);
+            if (downloadStatus) {
+                remoteTranslogTransferTracker.addDownloadBytesSucceeded(bytesToRead);
+            }
+        }
+
+        // Mark in FileTransferTracker so that the same files are not uploaded at the time of translog sync
+        fileTransferTracker.add(fileName, true);
+    }
+
+    public TranslogTransferMetadata readMetadata() throws IOException {
+        SetOnce<TranslogTransferMetadata> metadataSetOnce = new SetOnce<>();
+        SetOnce<IOException> exceptionSetOnce = new SetOnce<>();
+        final CountDownLatch latch = new CountDownLatch(1);
+        LatchedActionListener<List<BlobMetadata>> latchedActionListener = new LatchedActionListener<>(
+            ActionListener.wrap(blobMetadataList -> {
+                if (blobMetadataList.isEmpty()) return;
+                RemoteStoreUtils.verifyNoMultipleWriters(
+                    blobMetadataList.stream().map(BlobMetadata::name).collect(Collectors.toList()),
+                    TranslogTransferMetadata::getNodeIdByPrimaryTermAndGen
+                );
+                String filename = blobMetadataList.get(0).name();
+                boolean downloadStatus = false;
+                long downloadStartTime = System.nanoTime(), bytesToRead = 0;
+                try (InputStream inputStream = transferService.downloadBlob(remoteMetadataTransferPath, filename)) {
+                    // Capture number of bytes for stats before reading
+                    bytesToRead = inputStream.available();
+                    IndexInput indexInput = new ByteArrayIndexInput("metadata file", inputStream.readAllBytes());
+                    metadataSetOnce.set(metadataStreamWrapper.readStream(indexInput));
+                    downloadStatus = true;
+                } catch (IOException e) {
+                    logger.error(() -> new ParameterizedMessage("Exception while reading metadata file: {}", filename), e);
+                    exceptionSetOnce.set(e);
+                } finally {
+                    remoteTranslogTransferTracker.addDownloadTimeInMillis((System.nanoTime() - downloadStartTime) / 1_000_000L);
+                    logger.debug("translogMetadataDownloadStatus={}", downloadStatus);
+                    if (downloadStatus) {
+                        remoteTranslogTransferTracker.addDownloadBytesSucceeded(bytesToRead);
+                    }
+                }
+            }, e -> {
+                if (e instanceof RuntimeException) {
+                    throw (RuntimeException) e;
+                }
+                logger.error(() -> new ParameterizedMessage("Exception while listing metadata files"), e);
+                exceptionSetOnce.set((IOException) e);
+            }),
+            latch
+        );
+
+        try {
+            transferService.listAllInSortedOrder(
+                remoteMetadataTransferPath,
+                TranslogTransferMetadata.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH,
+                latchedActionListener
+            );
+            latch.await();
+        } catch (InterruptedException e) {
+            throw new IOException("Exception while reading/downloading metadafile", e);
+        }
+
+        if (exceptionSetOnce.get() != null) {
+            throw exceptionSetOnce.get();
+        }
+
+        return metadataSetOnce.get();
+    }
+
+    private TransferFileSnapshot prepareMetadata(TransferSnapshot transferSnapshot) throws IOException {
+        Map<String, String> generationPrimaryTermMap = transferSnapshot.getTranslogFileSnapshots().stream().map(s -> {
+            assert s instanceof TranslogFileSnapshot;
+            return (TranslogFileSnapshot) s;
+        })
+            .collect(
+                Collectors.toMap(
+                    snapshot -> String.valueOf(snapshot.getGeneration()),
+                    snapshot -> String.valueOf(snapshot.getPrimaryTerm())
+                )
+            );
+        TranslogTransferMetadata translogTransferMetadata = transferSnapshot.getTranslogTransferMetadata();
+        translogTransferMetadata.setGenerationToPrimaryTermMapper(new HashMap<>(generationPrimaryTermMap));
+
+        return new TransferFileSnapshot(
+            translogTransferMetadata.getFileName(),
+            getMetadataBytes(translogTransferMetadata),
+            translogTransferMetadata.getPrimaryTerm()
+        );
+    }
+
+    /**
+     * Get the metadata bytes for a {@link TranslogTransferMetadata} object
+     *
+     * @param metadata The object to be parsed
+     * @return Byte representation for the given metadata
+     */
+    public byte[] getMetadataBytes(TranslogTransferMetadata metadata) throws IOException {
+        byte[] metadataBytes;
+
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            try (
+                OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput(
+                    "translog transfer metadata " + metadata.getPrimaryTerm(),
+                    metadata.getFileName(),
+                    output,
+                    TranslogTransferMetadata.BUFFER_SIZE
+                )
+            ) {
+                metadataStreamWrapper.writeStream(indexOutput, metadata);
+            }
+            metadataBytes = BytesReference.toBytes(output.bytes());
+        }
+
+        return metadataBytes;
+    }
+
+    /**
+     * This method handles deletion of multiple generations for a single primary term. The deletion happens for translog
+     * and metadata files.
+     *
+     * @param primaryTerm primary term where the generations will be deleted.
+     * @param generations set of generation to delete.
+     * @param onCompletion runnable to run on completion of deletion regardless of success/failure.
+     */
+    public void deleteGenerationAsync(long primaryTerm, Set<Long> generations, Runnable onCompletion) {
+        List<String> translogFiles = new ArrayList<>();
+        generations.forEach(generation -> {
+            // Add .ckp and .tlog file to translog file list which is located in basePath/<primaryTerm>
+            String ckpFileName = Translog.getCommitCheckpointFileName(generation);
+            String translogFileName = Translog.getFilename(generation);
+            translogFiles.addAll(List.of(ckpFileName, translogFileName));
+        });
+        // Delete the translog and checkpoint files asynchronously
+        deleteTranslogFilesAsync(primaryTerm, translogFiles, onCompletion);
+    }
+
+    /**
+     * Deletes all primary terms from remote store that are more than the given {@code minPrimaryTermToKeep}. The caller
+     * of the method must ensure that the value is lesser than equal to the minimum primary term referenced by the remote
+     * translog metadata.
+     *
+     * @param minPrimaryTermToKeep all primary terms below this primary term are deleted.
+     */
+    public void deletePrimaryTermsAsync(long minPrimaryTermToKeep) {
+        logger.info("Deleting primary terms from remote store lesser than {}", minPrimaryTermToKeep);
+        transferService.listFoldersAsync(ThreadPool.Names.REMOTE_PURGE, remoteDataTransferPath, new ActionListener<>() {
+            @Override
+            public void onResponse(Set<String> folders) {
+                Set<Long> primaryTermsInRemote = folders.stream().filter(folderName -> {
+                    try {
+                        Long.parseLong(folderName);
+                        return true;
+                    } catch (Exception ignored) {
+                        // NO-OP
+                    }
+                    return false;
+                }).map(Long::parseLong).collect(Collectors.toSet());
+                Set<Long> primaryTermsToDelete = primaryTermsInRemote.stream()
+                    .filter(term -> term < minPrimaryTermToKeep)
+                    .collect(Collectors.toSet());
+                primaryTermsToDelete.forEach(term -> deletePrimaryTermAsync(term));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Exception occurred while getting primary terms from remote store", e);
+            }
+        });
+    }
+
+    /**
+     * Handles deletion of all translog files associated with a primary term.
+     *
+     * @param primaryTerm primary term.
+     */
+    private void deletePrimaryTermAsync(long primaryTerm) {
+        transferService.deleteAsync(
+            ThreadPool.Names.REMOTE_PURGE,
+            remoteDataTransferPath.add(String.valueOf(primaryTerm)),
+            new ActionListener<>() {
+                @Override
+                public void onResponse(Void unused) {
+                    logger.info("Deleted primary term {}", primaryTerm);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(new ParameterizedMessage("Exception occurred while deleting primary term {}", primaryTerm), e);
+                }
+            }
+        );
+    }
+
+    public void delete() {
+        // cleans up all the translog contents in async fashion
+        transferService.deleteAsync(ThreadPool.Names.REMOTE_PURGE, remoteBaseTransferPath, new ActionListener<>() {
+            @Override
+            public void onResponse(Void unused) {
+                logger.info("Deleted all remote translog data");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Exception occurred while cleaning translog", e);
+            }
+        });
+    }
+
+    public void deleteStaleTranslogMetadataFilesAsync(Runnable onCompletion) {
+        try {
+            transferService.listAllInSortedOrderAsync(
+                ThreadPool.Names.REMOTE_PURGE,
+                remoteMetadataTransferPath,
+                TranslogTransferMetadata.METADATA_PREFIX,
+                Integer.MAX_VALUE,
+                new ActionListener<>() {
+                    @Override
+                    public void onResponse(List<BlobMetadata> blobMetadata) {
+                        List<String> sortedMetadataFiles = blobMetadata.stream().map(BlobMetadata::name).collect(Collectors.toList());
+                        if (sortedMetadataFiles.size() <= 1) {
+                            logger.trace("Remote Metadata file count is {}, so skipping deletion", sortedMetadataFiles.size());
+                            onCompletion.run();
+                            return;
+                        }
+                        List<String> metadataFilesToDelete = sortedMetadataFiles.subList(1, sortedMetadataFiles.size());
+                        logger.trace("Deleting remote translog metadata files {}", metadataFilesToDelete);
+                        deleteMetadataFilesAsync(metadataFilesToDelete, onCompletion);
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        logger.error("Exception occurred while listing translog metadata files from remote store", e);
+                        onCompletion.run();
+                    }
+                }
+            );
+        } catch (Exception e) {
+            logger.error("Exception occurred while listing translog metadata files from remote store", e);
+            onCompletion.run();
+        }
+    }
+
+    public void deleteTranslogFiles() throws IOException {
+        transferService.delete(remoteMetadataTransferPath);
+        transferService.delete(remoteDataTransferPath);
+    }
+
+    /**
+     * Deletes list of translog files asynchronously using the {@code REMOTE_PURGE} threadpool.
+     *
+     * @param primaryTerm primary term of translog files.
+     * @param files       list of translog files to be deleted.
+     * @param onCompletion runnable to run on completion of deletion regardless of success/failure.
+     */
+    private void deleteTranslogFilesAsync(long primaryTerm, List<String> files, Runnable onCompletion) {
+        try {
+            transferService.deleteBlobsAsync(
+                ThreadPool.Names.REMOTE_PURGE,
+                remoteDataTransferPath.add(String.valueOf(primaryTerm)),
+                files,
+                new ActionListener<>() {
+                    @Override
+                    public void onResponse(Void unused) {
+                        fileTransferTracker.delete(files);
+                        logger.trace("Deleted translogs for primaryTerm={} files={}", primaryTerm, files);
+                        onCompletion.run();
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        onCompletion.run();
+                        logger.error(
+                            () -> new ParameterizedMessage(
+                                "Exception occurred while deleting translog for primaryTerm={} files={}",
+                                primaryTerm,
+                                files
+                            ),
+                            e
+                        );
+                    }
+                }
+            );
+        } catch (Exception e) {
+            onCompletion.run();
+            throw e;
+        }
+    }
+
+    /**
+     * Deletes metadata files asynchronously using the {@code REMOTE_PURGE} threadpool. On success or failure, runs {@code onCompletion}.
+     *
+     * @param files list of metadata files to be deleted.
+     * @param onCompletion runnable to run on completion of deletion regardless of success/failure.
+     */
+    private void deleteMetadataFilesAsync(List<String> files, Runnable onCompletion) {
+        try {
+            transferService.deleteBlobsAsync(ThreadPool.Names.REMOTE_PURGE, remoteMetadataTransferPath, files, new ActionListener<>() {
+                @Override
+                public void onResponse(Void unused) {
+                    onCompletion.run();
+                    logger.trace("Deleted remote translog metadata files {}", files);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    onCompletion.run();
+                    logger.error(new ParameterizedMessage("Exception occurred while deleting remote translog metadata files {}", files), e);
+                }
+            });
+        } catch (Exception e) {
+            onCompletion.run();
+            throw e;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java
new file mode 100644
index 0000000000000..07ec9160db1e3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java
@@ -0,0 +1,142 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.index.remote.RemoteStoreUtils;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * The metadata associated with every transfer {@link TransferSnapshot}. The metadata is uploaded at the end of the
+ * tranlog and generational checkpoint uploads to mark the latest generation and the translog/checkpoint files that are
+ * still referenced by the last checkpoint.
+ *
+ * @opensearch.internal
+ */
+public class TranslogTransferMetadata {
+
+    private final long primaryTerm;
+
+    private final long generation;
+
+    private final long minTranslogGeneration;
+
+    private final int count;
+
+    private final SetOnce<Map<String, String>> generationToPrimaryTermMapper = new SetOnce<>();
+
+    public static final String METADATA_SEPARATOR = "__";
+
+    public static final String METADATA_PREFIX = "metadata";
+
+    static final int BUFFER_SIZE = 4096;
+
+    static final int CURRENT_VERSION = 1;
+
+    static final String METADATA_CODEC = "md";
+
+    private final long createdAt;
+
+    private final String nodeId;
+
+    public TranslogTransferMetadata(long primaryTerm, long generation, long minTranslogGeneration, int count, String nodeId) {
+        this.primaryTerm = primaryTerm;
+        this.generation = generation;
+        this.minTranslogGeneration = minTranslogGeneration;
+        this.count = count;
+        this.createdAt = System.currentTimeMillis();
+        this.nodeId = nodeId;
+    }
+
+    /*
+    Used only at the time of download . Since details are read from content , nodeId is not available
+     */
+    public TranslogTransferMetadata(long primaryTerm, long generation, long minTranslogGeneration, int count) {
+        this(primaryTerm, generation, minTranslogGeneration, count, "");
+    }
+
+    public long getPrimaryTerm() {
+        return primaryTerm;
+    }
+
+    public long getGeneration() {
+        return generation;
+    }
+
+    public long getMinTranslogGeneration() {
+        return minTranslogGeneration;
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    public void setGenerationToPrimaryTermMapper(Map<String, String> generationToPrimaryTermMap) {
+        generationToPrimaryTermMapper.set(generationToPrimaryTermMap);
+    }
+
+    public Map<String, String> getGenerationToPrimaryTermMapper() {
+        return generationToPrimaryTermMapper.get();
+    }
+
+    /*
+    This should be used only at the time of creation.
+     */
+    public String getFileName() {
+        return String.join(
+            METADATA_SEPARATOR,
+            Arrays.asList(
+                METADATA_PREFIX,
+                RemoteStoreUtils.invertLong(primaryTerm),
+                RemoteStoreUtils.invertLong(generation),
+                RemoteStoreUtils.invertLong(createdAt),
+                nodeId,
+                String.valueOf(CURRENT_VERSION)
+            )
+        );
+    }
+
+    public static Tuple<Tuple<Long, Long>, String> getNodeIdByPrimaryTermAndGeneration(String filename) {
+        String[] tokens = filename.split(METADATA_SEPARATOR);
+        if (tokens.length < 6) {
+            // For versions < 2.11, we don't have node id
+            return null;
+        }
+        return new Tuple<>(new Tuple<>(RemoteStoreUtils.invertLong(tokens[1]), RemoteStoreUtils.invertLong(tokens[2])), tokens[4]);
+    }
+
+    public static Tuple<String, String> getNodeIdByPrimaryTermAndGen(String filename) {
+        String[] tokens = filename.split(METADATA_SEPARATOR);
+        if (tokens.length < 6) {
+            // For versions < 2.11, we don't have node id.
+            return null;
+        }
+        String primaryTermAndGen = String.join(METADATA_SEPARATOR, tokens[1], tokens[2]);
+
+        String nodeId = tokens[4];
+        return new Tuple<>(primaryTermAndGen, nodeId);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(primaryTerm, generation);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        TranslogTransferMetadata other = (TranslogTransferMetadata) o;
+        return Objects.equals(this.primaryTerm, other.primaryTerm) && Objects.equals(this.generation, other.generation);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandler.java b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandler.java
new file mode 100644
index 0000000000000..cea7ef8a4e6dd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandler.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.common.io.IndexIOStreamHandler;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Handler for {@link TranslogTransferMetadata}
+ *
+ * @opensearch.internal
+ */
+public class TranslogTransferMetadataHandler implements IndexIOStreamHandler<TranslogTransferMetadata> {
+
+    /**
+     * Implements logic to read content from file input stream {@code indexInput} and parse into {@link TranslogTransferMetadata}
+     *
+     * @param indexInput file input stream
+     * @return content parsed to {@link TranslogTransferMetadata}
+     */
+    @Override
+    public TranslogTransferMetadata readContent(IndexInput indexInput) throws IOException {
+        long primaryTerm = indexInput.readLong();
+        long generation = indexInput.readLong();
+        long minTranslogGeneration = indexInput.readLong();
+        Map<String, String> generationToPrimaryTermMapper = indexInput.readMapOfStrings();
+
+        int count = generationToPrimaryTermMapper.size();
+        TranslogTransferMetadata metadata = new TranslogTransferMetadata(primaryTerm, generation, minTranslogGeneration, count);
+        metadata.setGenerationToPrimaryTermMapper(generationToPrimaryTermMapper);
+
+        return metadata;
+    }
+
+    /**
+     * Implements logic to write content from {@code content} to file output stream {@code indexOutput}
+     *
+     * @param indexOutput file input stream
+     * @param content metadata content to be written
+     */
+    @Override
+    public void writeContent(IndexOutput indexOutput, TranslogTransferMetadata content) throws IOException {
+        indexOutput.writeLong(content.getPrimaryTerm());
+        indexOutput.writeLong(content.getGeneration());
+        indexOutput.writeLong(content.getMinTranslogGeneration());
+        if (content.getGenerationToPrimaryTermMapper() != null) {
+            indexOutput.writeMapOfStrings(content.getGenerationToPrimaryTermMapper());
+        } else {
+            indexOutput.writeMapOfStrings(new HashMap<>());
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/listener/FileTransferListener.java b/server/src/main/java/org/opensearch/index/translog/transfer/listener/FileTransferListener.java
new file mode 100644
index 0000000000000..af78cb50b63c6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/listener/FileTransferListener.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer.listener;
+
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+
+/**
+ * The listener to be invoked on the completion or failure of a {@link TransferFileSnapshot} or deletion of file
+ *
+ * @opensearch.internal
+ */
+public interface FileTransferListener {
+
+    /**
+     * Invoked when the transfer of a single {@link TransferFileSnapshot} succeeds
+     * @param fileSnapshot the corresponding file snapshot
+     */
+    void onSuccess(TransferFileSnapshot fileSnapshot);
+
+    /**
+     * Invoked when the transfer of a single {@link TransferFileSnapshot} fails
+     * @param fileSnapshot the corresponding file snapshot
+     * @param e the exception while processing the {@link TransferFileSnapshot}
+     */
+    void onFailure(TransferFileSnapshot fileSnapshot, Exception e);
+
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/listener/TranslogTransferListener.java b/server/src/main/java/org/opensearch/index/translog/transfer/listener/TranslogTransferListener.java
new file mode 100644
index 0000000000000..132d1adf916da
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/listener/TranslogTransferListener.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer.listener;
+
+import org.opensearch.index.translog.transfer.TransferSnapshot;
+
+import java.io.IOException;
+
+/**
+ * The listener to be invoked on the completion or failure of a {@link TransferSnapshot}
+ *
+ * @opensearch.internal
+ */
+public interface TranslogTransferListener {
+    /**
+     * Invoked when the transfer of {@link TransferSnapshot} succeeds
+     * @param transferSnapshot the transfer snapshot
+     * @throws IOException the exception during the transfer of data
+     */
+    void onUploadComplete(TransferSnapshot transferSnapshot) throws IOException;
+
+    /**
+     * Invoked when the transfer of {@link TransferSnapshot} fails
+     * @param transferSnapshot the transfer snapshot
+     * @param ex the exception while processing the {@link TransferSnapshot}
+     * @throws IOException the exception during the transfer of data
+     */
+    void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/listener/package-info.java b/server/src/main/java/org/opensearch/index/translog/transfer/listener/package-info.java
new file mode 100644
index 0000000000000..edb7f453515b1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/listener/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all translog operations */
+package org.opensearch.index.translog.transfer.listener;
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/package-info.java b/server/src/main/java/org/opensearch/index/translog/transfer/package-info.java
new file mode 100644
index 0000000000000..2ac96b01b0673
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all translog operations */
+package org.opensearch.index.translog.transfer;
diff --git a/server/src/main/java/org/opensearch/index/warmer/ShardIndexWarmerService.java b/server/src/main/java/org/opensearch/index/warmer/ShardIndexWarmerService.java
index 225400818f200..cadff0d3838f9 100644
--- a/server/src/main/java/org/opensearch/index/warmer/ShardIndexWarmerService.java
+++ b/server/src/main/java/org/opensearch/index/warmer/ShardIndexWarmerService.java
@@ -35,12 +35,17 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.metrics.MeanMetric;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.AbstractIndexShardComponent;
-import org.opensearch.index.shard.ShardId;
 
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Warms the index into the cache
+ *
+ * @opensearch.internal
+ */
 public class ShardIndexWarmerService extends AbstractIndexShardComponent {
 
     private final CounterMetric current = new CounterMetric();
diff --git a/server/src/main/java/org/opensearch/index/warmer/WarmerStats.java b/server/src/main/java/org/opensearch/index/warmer/WarmerStats.java
index 0d4241aa534ec..375dcc029fa70 100644
--- a/server/src/main/java/org/opensearch/index/warmer/WarmerStats.java
+++ b/server/src/main/java/org/opensearch/index/warmer/WarmerStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.index.warmer;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats collected about the warmer
+ *
+ * @opensearch.internal
+ */
 public class WarmerStats implements Writeable, ToXContentFragment {
 
     private long current;
@@ -115,6 +120,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields for warmer statistics
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String WARMER = "warmer";
         static final String CURRENT = "current";
diff --git a/server/src/main/java/org/opensearch/index/warmer/package-info.java b/server/src/main/java/org/opensearch/index/warmer/package-info.java
new file mode 100644
index 0000000000000..b3635b6ea286a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/index/warmer/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Core classes responsible for handling all indexing warming operations */
+package org.opensearch.index.warmer;
diff --git a/server/src/main/java/org/opensearch/indices/AbstractIndexShardCacheEntity.java b/server/src/main/java/org/opensearch/indices/AbstractIndexShardCacheEntity.java
index 4717867a5245d..bb1201cb910a9 100644
--- a/server/src/main/java/org/opensearch/indices/AbstractIndexShardCacheEntity.java
+++ b/server/src/main/java/org/opensearch/indices/AbstractIndexShardCacheEntity.java
@@ -32,13 +32,16 @@
 
 package org.opensearch.indices;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.cache.RemovalNotification;
+import org.opensearch.common.cache.RemovalReason;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.cache.request.ShardRequestCache;
 import org.opensearch.index.shard.IndexShard;
 
 /**
  * Abstract base class for the an {@link IndexShard} level {@linkplain IndicesRequestCache.CacheEntity}.
+ *
+ * @opensearch.internal
  */
 abstract class AbstractIndexShardCacheEntity implements IndicesRequestCache.CacheEntity {
 
@@ -64,10 +67,6 @@ public final void onMiss() {
 
     @Override
     public final void onRemoval(RemovalNotification<IndicesRequestCache.Key, BytesReference> notification) {
-        stats().onRemoval(
-            notification.getKey(),
-            notification.getValue(),
-            notification.getRemovalReason() == RemovalNotification.RemovalReason.EVICTED
-        );
+        stats().onRemoval(notification.getKey(), notification.getValue(), notification.getRemovalReason() == RemovalReason.EVICTED);
     }
 }
diff --git a/server/src/main/java/org/opensearch/indices/AliasFilterParsingException.java b/server/src/main/java/org/opensearch/indices/AliasFilterParsingException.java
index 0a2c292ab7765..1f8fc5f1dd7d0 100644
--- a/server/src/main/java/org/opensearch/indices/AliasFilterParsingException.java
+++ b/server/src/main/java/org/opensearch/indices/AliasFilterParsingException.java
@@ -33,11 +33,16 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown for parsing alias filters
+ *
+ * @opensearch.internal
+ */
 public class AliasFilterParsingException extends OpenSearchException {
 
     public AliasFilterParsingException(Index index, String name, String desc, Throwable ex) {
diff --git a/server/src/main/java/org/opensearch/indices/IndexClosedException.java b/server/src/main/java/org/opensearch/indices/IndexClosedException.java
index aa2971e598e06..cf5c46f9294b3 100644
--- a/server/src/main/java/org/opensearch/indices/IndexClosedException.java
+++ b/server/src/main/java/org/opensearch/indices/IndexClosedException.java
@@ -33,14 +33,16 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Exception indicating that one or more requested indices are closed.
+ *
+ * @opensearch.internal
  */
 public class IndexClosedException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/indices/IndexCreationException.java b/server/src/main/java/org/opensearch/indices/IndexCreationException.java
index fde1ad623fa12..cd604176441ef 100644
--- a/server/src/main/java/org/opensearch/indices/IndexCreationException.java
+++ b/server/src/main/java/org/opensearch/indices/IndexCreationException.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if there is an error creating an index
+ *
+ * @opensearch.internal
+ */
 public class IndexCreationException extends OpenSearchException implements OpenSearchWrapperException {
 
     public IndexCreationException(String index, Throwable cause) {
diff --git a/server/src/main/java/org/opensearch/indices/IndexPrimaryShardNotAllocatedException.java b/server/src/main/java/org/opensearch/indices/IndexPrimaryShardNotAllocatedException.java
index 2e680e6d0aa77..68bd3202231f8 100644
--- a/server/src/main/java/org/opensearch/indices/IndexPrimaryShardNotAllocatedException.java
+++ b/server/src/main/java/org/opensearch/indices/IndexPrimaryShardNotAllocatedException.java
@@ -33,15 +33,17 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Thrown when some action cannot be performed because the primary shard of
  * some shard group in an index has not been allocated post api action.
+ *
+ * @opensearch.internal
  */
 public class IndexPrimaryShardNotAllocatedException extends OpenSearchException {
     public IndexPrimaryShardNotAllocatedException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/indices/IndexTemplateMissingException.java b/server/src/main/java/org/opensearch/indices/IndexTemplateMissingException.java
index fde9ef3712cf0..fc55c9d82eddd 100644
--- a/server/src/main/java/org/opensearch/indices/IndexTemplateMissingException.java
+++ b/server/src/main/java/org/opensearch/indices/IndexTemplateMissingException.java
@@ -32,12 +32,17 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an index template is missing
+ *
+ * @opensearch.internal
+ */
 public class IndexTemplateMissingException extends OpenSearchException {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/indices/IndexingMemoryController.java b/server/src/main/java/org/opensearch/indices/IndexingMemoryController.java
index 1917a224e5410..93b75218fd1c6 100644
--- a/server/src/main/java/org/opensearch/indices/IndexingMemoryController.java
+++ b/server/src/main/java/org/opensearch/indices/IndexingMemoryController.java
@@ -39,15 +39,15 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.IndexingOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.threadpool.Scheduler.Cancellable;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
@@ -62,6 +62,11 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantLock;
 
+/**
+ * Memory controller for indexing operations
+ *
+ * @opensearch.internal
+ */
 public class IndexingMemoryController implements IndexingOperationListener, Closeable {
 
     private static final Logger logger = LogManager.getLogger(IndexingMemoryController.class);
@@ -255,6 +260,11 @@ private void recordOperationBytes(Engine.Operation operation, Engine.Result resu
         }
     }
 
+    /**
+     * The bytes used by a shard and a reference to the shard
+     *
+     * @opensearch.internal
+     */
     private static final class ShardAndBytesUsed implements Comparable<ShardAndBytesUsed> {
         final long bytesUsed;
         final IndexShard shard;
diff --git a/server/src/main/java/org/opensearch/indices/IndicesModule.java b/server/src/main/java/org/opensearch/indices/IndicesModule.java
index e685ea52aa5ca..5c2137ec742a4 100644
--- a/server/src/main/java/org/opensearch/indices/IndicesModule.java
+++ b/server/src/main/java/org/opensearch/indices/IndicesModule.java
@@ -37,18 +37,21 @@
 import org.opensearch.action.admin.indices.rollover.MaxDocsCondition;
 import org.opensearch.action.admin.indices.rollover.MaxSizeCondition;
 import org.opensearch.action.resync.TransportResyncReplicationAction;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.inject.AbstractModule;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.index.SegmentReplicationPressureService;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.BooleanFieldMapper;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.DataStreamFieldMapper;
 import org.opensearch.index.mapper.DateFieldMapper;
+import org.opensearch.index.mapper.DocCountFieldMapper;
 import org.opensearch.index.mapper.FieldAliasMapper;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
+import org.opensearch.index.mapper.FlatObjectFieldMapper;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
@@ -57,6 +60,7 @@
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MetadataFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.mapper.RangeType;
@@ -64,15 +68,16 @@
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.SourceFieldMapper;
 import org.opensearch.index.mapper.TextFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.VersionFieldMapper;
+import org.opensearch.index.remote.RemoteStorePressureService;
+import org.opensearch.index.seqno.GlobalCheckpointSyncAction;
 import org.opensearch.index.seqno.RetentionLeaseBackgroundSyncAction;
 import org.opensearch.index.seqno.RetentionLeaseSyncAction;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
-import org.opensearch.index.seqno.GlobalCheckpointSyncAction;
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.mapper.MapperRegistry;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.indices.store.IndicesStore;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
 import org.opensearch.plugins.MapperPlugin;
@@ -89,6 +94,8 @@
 
 /**
  * Configures classes and services that are shared by indices on each node.
+ *
+ * @opensearch.internal
  */
 public class IndicesModule extends AbstractModule {
     private final List<Entry> namedWritables = new ArrayList<>();
@@ -157,6 +164,7 @@ public static Map<String, Mapper.TypeParser> getMappers(List<MapperPlugin> mappe
         mappers.put(CompletionFieldMapper.CONTENT_TYPE, CompletionFieldMapper.PARSER);
         mappers.put(FieldAliasMapper.CONTENT_TYPE, new FieldAliasMapper.TypeParser());
         mappers.put(GeoPointFieldMapper.CONTENT_TYPE, new GeoPointFieldMapper.TypeParser());
+        mappers.put(FlatObjectFieldMapper.CONTENT_TYPE, FlatObjectFieldMapper.PARSER);
 
         for (MapperPlugin mapperPlugin : mapperPlugins) {
             for (Map.Entry<String, Mapper.TypeParser> entry : mapperPlugin.getMappers().entrySet()) {
@@ -185,9 +193,10 @@ private static Map<String, MetadataFieldMapper.TypeParser> initBuiltInMetadataMa
         builtInMetadataMappers.put(IndexFieldMapper.NAME, IndexFieldMapper.PARSER);
         builtInMetadataMappers.put(DataStreamFieldMapper.NAME, DataStreamFieldMapper.PARSER);
         builtInMetadataMappers.put(SourceFieldMapper.NAME, SourceFieldMapper.PARSER);
-        builtInMetadataMappers.put(TypeFieldMapper.NAME, TypeFieldMapper.PARSER);
+        builtInMetadataMappers.put(NestedPathFieldMapper.NAME, NestedPathFieldMapper.PARSER);
         builtInMetadataMappers.put(VersionFieldMapper.NAME, VersionFieldMapper.PARSER);
         builtInMetadataMappers.put(SeqNoFieldMapper.NAME, SeqNoFieldMapper.PARSER);
+        builtInMetadataMappers.put(DocCountFieldMapper.NAME, DocCountFieldMapper.PARSER);
         // _field_names must be added last so that it has a chance to see all the other mappers
         builtInMetadataMappers.put(FieldNamesFieldMapper.NAME, FieldNamesFieldMapper.PARSER);
         return Collections.unmodifiableMap(builtInMetadataMappers);
@@ -276,6 +285,9 @@ protected void configure() {
         bind(RetentionLeaseSyncAction.class).asEagerSingleton();
         bind(RetentionLeaseBackgroundSyncAction.class).asEagerSingleton();
         bind(RetentionLeaseSyncer.class).asEagerSingleton();
+        bind(SegmentReplicationCheckpointPublisher.class).asEagerSingleton();
+        bind(SegmentReplicationPressureService.class).asEagerSingleton();
+        bind(RemoteStorePressureService.class).asEagerSingleton();
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/indices/IndicesQueryCache.java b/server/src/main/java/org/opensearch/indices/IndicesQueryCache.java
index 2cbb83fde278d..228723045d8cc 100644
--- a/server/src/main/java/org/opensearch/indices/IndicesQueryCache.java
+++ b/server/src/main/java/org/opensearch/indices/IndicesQueryCache.java
@@ -48,9 +48,9 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.cache.query.QueryCacheStats;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -62,6 +62,11 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Predicate;
 
+/**
+ * The query cache for indices
+ *
+ * @opensearch.internal
+ */
 public class IndicesQueryCache implements QueryCache, Closeable {
 
     private static final Logger logger = LogManager.getLogger(IndicesQueryCache.class);
@@ -123,13 +128,17 @@ public QueryCacheStats getStats(ShardId shard) {
 
         // We also have some shared ram usage that we try to distribute to
         // proportionally to their number of cache entries of each shard
-        long totalSize = 0;
-        for (QueryCacheStats s : stats.values()) {
-            totalSize += s.getCacheSize();
+        if (stats.isEmpty()) {
+            shardStats.add(new QueryCacheStats(sharedRamBytesUsed, 0, 0, 0, 0));
+        } else {
+            long totalSize = 0;
+            for (QueryCacheStats s : stats.values()) {
+                totalSize += s.getCacheSize();
+            }
+            final double weight = totalSize == 0 ? 1d / stats.size() : ((double) shardStats.getCacheSize()) / totalSize;
+            final long additionalRamBytesUsed = Math.round(weight * sharedRamBytesUsed);
+            shardStats.add(new QueryCacheStats(additionalRamBytesUsed, 0, 0, 0, 0));
         }
-        final double weight = totalSize == 0 ? 1d / stats.size() : ((double) shardStats.getCacheSize()) / totalSize;
-        final long additionalRamBytesUsed = Math.round(weight * sharedRamBytesUsed);
-        shardStats.add(new QueryCacheStats(additionalRamBytesUsed, 0, 0, 0, 0));
         return shardStats;
     }
 
@@ -211,6 +220,11 @@ public void close() {
         cache.clear();
     }
 
+    /**
+     * Statistics for the indices query cache
+     *
+     * @opensearch.internal
+     */
     private static class Stats implements Cloneable {
 
         final ShardId shardId;
@@ -246,6 +260,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Statistics and Counts
+     *
+     * @opensearch.internal
+     */
     private static class StatsAndCount {
         volatile int count;
         final Stats stats;
diff --git a/server/src/main/java/org/opensearch/indices/IndicesRequestCache.java b/server/src/main/java/org/opensearch/indices/IndicesRequestCache.java
index d82ec0afc2c98..629cea102a8b2 100644
--- a/server/src/main/java/org/opensearch/indices/IndicesRequestCache.java
+++ b/server/src/main/java/org/opensearch/indices/IndicesRequestCache.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.indices;
 
-import com.carrotsearch.hppc.ObjectHashSet;
-import com.carrotsearch.hppc.ObjectSet;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.DirectoryReader;
@@ -41,7 +39,6 @@
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.cache.Cache;
 import org.opensearch.common.cache.CacheBuilder;
 import org.opensearch.common.cache.CacheLoader;
@@ -51,14 +48,16 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Objects;
 import java.util.Set;
@@ -76,6 +75,8 @@
  * <p>
  * There are still several TODOs left in this class, some easily addressable, some more complex, but the support
  * is functional.
+ *
+ * @opensearch.internal
  */
 public final class IndicesRequestCache implements RemovalListener<IndicesRequestCache.Key, BytesReference>, Closeable {
 
@@ -174,6 +175,11 @@ void invalidate(CacheEntity cacheEntity, DirectoryReader reader, BytesReference
         cache.invalidate(new Key(cacheEntity, reader.getReaderCacheHelper().getKey(), cacheKey));
     }
 
+    /**
+     * Loader for the request cache
+     *
+     * @opensearch.internal
+     */
     private static class Loader implements CacheLoader<Key, BytesReference> {
 
         private final CacheEntity entity;
@@ -236,6 +242,11 @@ interface CacheEntity extends Accountable {
         void onRemoval(RemovalNotification<Key, BytesReference> notification);
     }
 
+    /**
+     * Unique key for the cache
+     *
+     * @opensearch.internal
+     */
     static class Key implements Accountable {
         private static final long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(Key.class);
 
@@ -318,8 +329,8 @@ public int hashCode() {
     }
 
     synchronized void cleanCache() {
-        final ObjectSet<CleanupKey> currentKeysToClean = new ObjectHashSet<>();
-        final ObjectSet<Object> currentFullClean = new ObjectHashSet<>();
+        final Set<CleanupKey> currentKeysToClean = new HashSet<>();
+        final Set<Object> currentFullClean = new HashSet<>();
         currentKeysToClean.clear();
         currentFullClean.clear();
         for (Iterator<CleanupKey> iterator = keysToClean.iterator(); iterator.hasNext();) {
diff --git a/server/src/main/java/org/opensearch/indices/IndicesService.java b/server/src/main/java/org/opensearch/indices/IndicesService.java
index 5caafb0ce60d4..45af7d2b39989 100644
--- a/server/src/main/java/org/opensearch/indices/IndicesService.java
+++ b/server/src/main/java/org/opensearch/indices/IndicesService.java
@@ -49,6 +49,7 @@
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags.Flag;
 import org.opensearch.action.admin.indices.stats.IndexShardStats;
 import org.opensearch.action.admin.indices.stats.ShardStats;
+import org.opensearch.action.search.SearchRequestStats;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
@@ -62,42 +63,43 @@
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.AbstractRefCounted;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.iterable.Iterables;
 import org.opensearch.common.util.set.Sets;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
 import org.opensearch.env.ShardLockObtainFailedException;
 import org.opensearch.gateway.MetaStateService;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
@@ -109,7 +111,9 @@
 import org.opensearch.index.engine.EngineConfigFactory;
 import org.opensearch.index.engine.EngineFactory;
 import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
 import org.opensearch.index.engine.NoOpEngine;
+import org.opensearch.index.engine.ReadOnlyEngine;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.flush.FlushStats;
 import org.opensearch.index.get.GetStats;
@@ -120,6 +124,7 @@
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.recovery.RecoveryStats;
 import org.opensearch.index.refresh.RefreshStats;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.search.stats.SearchStats;
 import org.opensearch.index.seqno.RetentionLeaseStats;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
@@ -130,13 +135,20 @@
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.IndexingOperationListener;
 import org.opensearch.index.shard.IndexingStats;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.index.shard.IndexingStats.Stats.DocStatusStats;
+import org.opensearch.index.store.remote.filecache.FileCacheCleaner;
+import org.opensearch.index.translog.InternalTranslogFactory;
+import org.opensearch.index.translog.RemoteBlobStoreInternalTranslogFactory;
+import org.opensearch.index.translog.TranslogFactory;
+import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
+import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.node.Node;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.plugins.PluginsService;
@@ -172,23 +184,30 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.LongSupplier;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
 import static org.opensearch.common.collect.MapBuilder.newMapBuilder;
-import static org.opensearch.common.util.CollectionUtils.arrayAsArrayList;
 import static org.opensearch.common.util.concurrent.OpenSearchExecutors.daemonThreadFactory;
+import static org.opensearch.core.common.util.CollectionUtils.arrayAsArrayList;
 import static org.opensearch.index.IndexService.IndexCreationContext.CREATE_INDEX;
 import static org.opensearch.index.IndexService.IndexCreationContext.METADATA_VERIFICATION;
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
+/**
+ * Main OpenSearch indices service
+ *
+ * @opensearch.internal
+ */
 public class IndicesService extends AbstractLifecycleComponent
     implements
         IndicesClusterStateService.AllocatedIndices<IndexShard, IndexService>,
@@ -214,6 +233,73 @@ public class IndicesService extends AbstractLifecycleComponent
         Setting.Property.NodeScope
     );
 
+    /**
+     * Used to specify SEGMENT replication type as the default replication strategy for all indices in a cluster. By default, this is false.
+     */
+    public static final String CLUSTER_SETTING_REPLICATION_TYPE = "cluster.indices.replication.strategy";
+
+    public static final Setting<ReplicationType> CLUSTER_REPLICATION_TYPE_SETTING = new Setting<>(
+        CLUSTER_SETTING_REPLICATION_TYPE,
+        ReplicationType.DOCUMENT.toString(),
+        ReplicationType::parseString,
+        Property.NodeScope,
+        Property.Final
+    );
+
+    /**
+     * Used to specify the default translog buffer interval for remote store backed indexes.
+     */
+    public static final Setting<TimeValue> CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING = Setting.timeSetting(
+        "cluster.remote_store.translog.buffer_interval",
+        IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+        IndexSettings.MINIMUM_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+        Property.NodeScope,
+        Property.Dynamic
+    );
+
+    /**
+     * This setting is used to set the refresh interval when the {@code index.refresh_interval} index setting is not
+     * provided during index creation or when the existing {@code index.refresh_interval} index setting is set as null.
+     * This comes handy when the user wants to set a default refresh interval across all indexes created in a cluster
+     * which is different from 1s and also at the same time have searchIdle feature supported. The setting can only be
+     * as low as the {@code cluster.minimum.index.refresh_interval}.
+     */
+    public static final Setting<TimeValue> CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING = Setting.timeSetting(
+        "cluster.default.index.refresh_interval",
+        IndexSettings.DEFAULT_REFRESH_INTERVAL,
+        IndexSettings.MINIMUM_REFRESH_INTERVAL,
+        new ClusterDefaultRefreshIntervalValidator(),
+        Property.NodeScope,
+        Property.Dynamic
+    );
+
+    /**
+     * This setting is used to set the minimum refresh interval applicable for all indexes in a cluster. The
+     * {@code cluster.default.index.refresh_interval} setting value needs to be higher than this setting's value. Index
+     * creation will fail if the index setting {@code index.refresh_interval} is supplied with a value lower than the
+     * cluster minimum refresh interval.
+     */
+    public static final Setting<TimeValue> CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING = Setting.timeSetting(
+        "cluster.minimum.index.refresh_interval",
+        IndexSettings.MINIMUM_REFRESH_INTERVAL,
+        IndexSettings.MINIMUM_REFRESH_INTERVAL,
+        new ClusterMinimumRefreshIntervalValidator(),
+        Property.NodeScope,
+        Property.Dynamic
+    );
+
+    /**
+     * This setting is used to restrict creation or updation of index where the `index.translog.durability` index setting
+     * is set as ASYNC if enabled. If disabled, any of the durability mode can be used and switched at any later time from
+     * one to another.
+     */
+    public static final Setting<Boolean> CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING = Setting.boolSetting(
+        "cluster.remote_store.index.restrict.async-durability",
+        false,
+        Property.NodeScope,
+        Property.Final
+    );
+
     /**
      * The node's settings.
      */
@@ -257,6 +343,13 @@ public class IndicesService extends AbstractLifecycleComponent
     private final Set<Index> danglingIndicesToWrite = Sets.newConcurrentHashSet();
     private final boolean nodeWriteDanglingIndicesInfo;
     private final ValuesSourceRegistry valuesSourceRegistry;
+    private final IndexStorePlugin.DirectoryFactory remoteDirectoryFactory;
+    private final BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier;
+    private volatile TimeValue clusterDefaultRefreshInterval;
+    private volatile TimeValue clusterRemoteTranslogBufferInterval;
+    private final FileCacheCleaner fileCacheCleaner;
+
+    private final SearchRequestStats searchRequestStats;
 
     @Override
     protected void doStart() {
@@ -284,7 +377,12 @@ public IndicesService(
         Collection<Function<IndexSettings, Optional<EngineFactory>>> engineFactoryProviders,
         Map<String, IndexStorePlugin.DirectoryFactory> directoryFactories,
         ValuesSourceRegistry valuesSourceRegistry,
-        Map<String, IndexStorePlugin.RecoveryStateFactory> recoveryStateFactories
+        Map<String, IndexStorePlugin.RecoveryStateFactory> recoveryStateFactories,
+        IndexStorePlugin.DirectoryFactory remoteDirectoryFactory,
+        Supplier<RepositoriesService> repositoriesServiceSupplier,
+        FileCacheCleaner fileCacheCleaner,
+        SearchRequestStats searchRequestStats,
+        @Nullable RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
     ) {
         this.settings = settings;
         this.threadPool = threadPool;
@@ -328,15 +426,9 @@ public void onRemoval(ShardId shardId, String fieldName, boolean wasEvicted, lon
         this.metaStateService = metaStateService;
         this.engineFactoryProviders = engineFactoryProviders;
 
-        // do not allow any plugin-provided index store type to conflict with a built-in type
-        for (final String indexStoreType : directoryFactories.keySet()) {
-            if (IndexModule.isBuiltinType(indexStoreType)) {
-                throw new IllegalStateException("registered index store type [" + indexStoreType + "] conflicts with a built-in type");
-            }
-        }
-
         this.directoryFactories = directoryFactories;
         this.recoveryStateFactories = recoveryStateFactories;
+        this.fileCacheCleaner = fileCacheCleaner;
         // doClose() is called when shutting down a node, yet there might still be ongoing requests
         // that we need to wait for before closing some resources such as the caches. In order to
         // avoid closing these resources while ongoing requests are still being processed, we use a
@@ -378,6 +470,49 @@ protected void closeInternal() {
 
         this.allowExpensiveQueries = ALLOW_EXPENSIVE_QUERIES.get(clusterService.getSettings());
         clusterService.getClusterSettings().addSettingsUpdateConsumer(ALLOW_EXPENSIVE_QUERIES, this::setAllowExpensiveQueries);
+        this.remoteDirectoryFactory = remoteDirectoryFactory;
+        this.translogFactorySupplier = getTranslogFactorySupplier(repositoriesServiceSupplier, threadPool, remoteStoreStatsTrackerFactory);
+        this.searchRequestStats = searchRequestStats;
+        this.clusterDefaultRefreshInterval = CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.get(clusterService.getSettings());
+        clusterService.getClusterSettings()
+            .addSettingsUpdateConsumer(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING, this::onRefreshIntervalUpdate);
+        this.clusterRemoteTranslogBufferInterval = CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(clusterService.getSettings());
+        clusterService.getClusterSettings()
+            .addSettingsUpdateConsumer(CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING, this::setClusterRemoteTranslogBufferInterval);
+    }
+
+    /**
+     * The changes to dynamic cluster setting {@code cluster.default.index.refresh_interval} needs to be updated. This
+     * method gets called whenever the setting changes. We set the instance variable with the updated value as this is
+     * also a supplier to all IndexService that have been created on the node. We also notify the change to all
+     * IndexService instances that are created on this node.
+     *
+     * @param clusterDefaultRefreshInterval the updated cluster default refresh interval.
+     */
+    private void onRefreshIntervalUpdate(TimeValue clusterDefaultRefreshInterval) {
+        this.clusterDefaultRefreshInterval = clusterDefaultRefreshInterval;
+        for (Map.Entry<String, IndexService> entry : indices.entrySet()) {
+            IndexService indexService = entry.getValue();
+            indexService.onRefreshIntervalChange();
+        }
+    }
+
+    private static BiFunction<IndexSettings, ShardRouting, TranslogFactory> getTranslogFactorySupplier(
+        Supplier<RepositoriesService> repositoriesServiceSupplier,
+        ThreadPool threadPool,
+        RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
+    ) {
+        return (indexSettings, shardRouting) -> {
+            if (indexSettings.isRemoteTranslogStoreEnabled() && shardRouting.primary()) {
+                return new RemoteBlobStoreInternalTranslogFactory(
+                    repositoriesServiceSupplier,
+                    threadPool,
+                    indexSettings.getRemoteStoreTranslogRepository(),
+                    remoteStoreStatsTrackerFactory.getRemoteTranslogTransferTracker(shardRouting.shardId())
+                );
+            }
+            return new InternalTranslogFactory();
+        };
     }
 
     private static final String DANGLING_INDICES_UPDATE_THREAD_NAME = "DanglingIndices#updateTask";
@@ -461,7 +596,7 @@ public NodeIndicesStats stats(CommonStatsFlags flags) {
             }
         }
 
-        return new NodeIndicesStats(commonStats, statsByShard(this, flags));
+        return new NodeIndicesStats(commonStats, statsByShard(this, flags), searchRequestStats);
     }
 
     Map<Index, List<IndexShardStats>> statsByShard(final IndicesService indicesService, final CommonStatsFlags flags) {
@@ -608,6 +743,7 @@ public void onStoreClosed(ShardId shardId) {
         };
         finalListeners.add(onStoreClose);
         finalListeners.add(oldShardsStats);
+        finalListeners.add(fileCacheCleaner);
         final IndexService indexService = createIndexService(
             CREATE_INDEX,
             indexMetadata,
@@ -737,7 +873,11 @@ private synchronized IndexService createIndexService(
             indicesFieldDataCache,
             namedWriteableRegistry,
             this::isIdFieldDataEnabled,
-            valuesSourceRegistry
+            valuesSourceRegistry,
+            remoteDirectoryFactory,
+            translogFactorySupplier,
+            this::getClusterDefaultRefreshInterval,
+            this::getClusterRemoteTranslogBufferInterval
         );
     }
 
@@ -757,6 +897,12 @@ private EngineFactory getEngineFactory(final IndexSettings idxSettings) {
             .filter(maybe -> Objects.requireNonNull(maybe).isPresent())
             .collect(Collectors.toList());
         if (engineFactories.isEmpty()) {
+            if (idxSettings.isRemoteSnapshot()) {
+                return config -> new ReadOnlyEngine(config, new SeqNoStats(0, 0, 0), new TranslogStats(), true, Function.identity(), false);
+            }
+            if (idxSettings.isSegRepEnabled()) {
+                return new NRTReplicationEngineFactory();
+            }
             return new InternalEngineFactory();
         } else if (engineFactories.size() == 1) {
             assert engineFactories.get(0).isPresent();
@@ -833,21 +979,29 @@ public synchronized void verifyIndexMetadata(IndexMetadata metadata, IndexMetada
     @Override
     public IndexShard createShard(
         final ShardRouting shardRouting,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
         final PeerRecoveryTargetService recoveryTargetService,
-        final PeerRecoveryTargetService.RecoveryListener recoveryListener,
+        final RecoveryListener recoveryListener,
         final RepositoriesService repositoriesService,
         final Consumer<IndexShard.ShardFailure> onShardFailure,
         final Consumer<ShardId> globalCheckpointSyncer,
         final RetentionLeaseSyncer retentionLeaseSyncer,
         final DiscoveryNode targetNode,
-        final DiscoveryNode sourceNode
+        final DiscoveryNode sourceNode,
+        final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
     ) throws IOException {
         Objects.requireNonNull(retentionLeaseSyncer);
         ensureChangesAllowed();
         IndexService indexService = indexService(shardRouting.index());
         assert indexService != null;
         RecoveryState recoveryState = indexService.createRecoveryState(shardRouting, targetNode, sourceNode);
-        IndexShard indexShard = indexService.createShard(shardRouting, globalCheckpointSyncer, retentionLeaseSyncer);
+        IndexShard indexShard = indexService.createShard(
+            shardRouting,
+            globalCheckpointSyncer,
+            retentionLeaseSyncer,
+            checkpointPublisher,
+            remoteStoreStatsTrackerFactory
+        );
         indexShard.addShardFailureCallback(onShardFailure);
         indexShard.startRecovery(recoveryState, recoveryTargetService, recoveryListener, repositoriesService, mapping -> {
             assert recoveryState.getRecoverySource().getType() == RecoverySource.Type.LOCAL_SHARDS
@@ -856,7 +1010,7 @@ public IndexShard createShard(
                 .indices()
                 .preparePutMapping()
                 .setConcreteIndex(shardRouting.index()) // concrete index - no name clash, it uses uuid
-                .setSource(mapping.source().string(), XContentType.JSON)
+                .setSource(mapping.source().string(), MediaTypeRegistry.JSON)
                 .get();
         }, this);
         return indexShard;
@@ -908,6 +1062,20 @@ public IndicesQueryCache getIndicesQueryCache() {
         return indicesQueryCache;
     }
 
+    /**
+     * Accumulate stats from the passed Object
+     *
+     * @param stats Instance storing {@link DocStatusStats}
+     */
+    public void addDocStatusStats(final DocStatusStats stats) {
+        oldShardsStats.indexingStats.getTotal().getDocStatusStats().add(stats);
+    }
+
+    /**
+     * Statistics for old shards
+     *
+     * @opensearch.internal
+     */
     static class OldShardsStats implements IndexEventListener {
 
         final SearchStats searchStats = new SearchStats();
@@ -1231,6 +1399,11 @@ private void addPendingDelete(Index index, PendingDelete pendingDelete) {
         }
     }
 
+    /**
+     * A pending delete
+     *
+     * @opensearch.internal
+     */
     private static final class PendingDelete implements Comparable<PendingDelete> {
         final Index index;
         final int shardId;
@@ -1381,6 +1554,8 @@ public AnalysisRegistry getAnalysis() {
      * periodically. In this case it is the field data cache, because a cache that
      * has an entry invalidated may not clean up the entry if it is not read from
      * or written to after invalidation.
+     *
+     * @opensearch.internal
      */
     private static final class CacheCleaner implements Runnable, Releasable {
 
@@ -1569,6 +1744,11 @@ private BytesReference cacheShardLevelResult(
         return indicesRequestCache.getOrCompute(cacheEntity, supplier, reader, cacheKey);
     }
 
+    /**
+     * An item in the index shard cache
+     *
+     * @opensearch.internal
+     */
     static final class IndexShardCacheEntity extends AbstractIndexShardCacheEntity {
         private static final long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(IndexShardCacheEntity.class);
         private final IndexShard indexShard;
@@ -1616,7 +1796,7 @@ public AliasFilter buildAliasFilter(ClusterState state, String index, Set<String
         CheckedFunction<BytesReference, QueryBuilder, IOException> filterParser = bytes -> {
             try (
                 InputStream inputStream = bytes.streamInput();
-                XContentParser parser = XContentFactory.xContentType(inputStream)
+                XContentParser parser = MediaTypeRegistry.xContentType(inputStream)
                     .xContent()
                     .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, inputStream)
             ) {
@@ -1748,4 +1928,85 @@ public boolean allPendingDanglingIndicesWritten() {
         return nodeWriteDanglingIndicesInfo == false
             || (danglingIndicesToWrite.isEmpty() && danglingIndicesThreadPoolExecutor.getActiveCount() == 0);
     }
+
+    /**
+     * Validates the cluster default index refresh interval.
+     *
+     * @opensearch.internal
+     */
+    private static final class ClusterDefaultRefreshIntervalValidator implements Setting.Validator<TimeValue> {
+
+        @Override
+        public void validate(TimeValue value) {
+
+        }
+
+        @Override
+        public void validate(final TimeValue defaultRefreshInterval, final Map<Setting<?>, Object> settings) {
+            final TimeValue minimumRefreshInterval = (TimeValue) settings.get(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING);
+            validateRefreshIntervalSettings(minimumRefreshInterval, defaultRefreshInterval);
+        }
+
+        @Override
+        public Iterator<Setting<?>> settings() {
+            final List<Setting<?>> settings = List.of(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING);
+            return settings.iterator();
+        }
+    }
+
+    /**
+     * Validates the cluster minimum index refresh interval.
+     *
+     * @opensearch.internal
+     */
+    private static final class ClusterMinimumRefreshIntervalValidator implements Setting.Validator<TimeValue> {
+
+        @Override
+        public void validate(TimeValue value) {
+
+        }
+
+        @Override
+        public void validate(final TimeValue minimumRefreshInterval, final Map<Setting<?>, Object> settings) {
+            final TimeValue defaultRefreshInterval = (TimeValue) settings.get(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING);
+            validateRefreshIntervalSettings(minimumRefreshInterval, defaultRefreshInterval);
+        }
+
+        @Override
+        public Iterator<Setting<?>> settings() {
+            final List<Setting<?>> settings = List.of(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING);
+            return settings.iterator();
+        }
+    }
+
+    /**
+     * Validates that the cluster minimum refresh interval is not more than the cluster default refresh interval.
+     *
+     * @param minimumRefreshInterval value of cluster minimum index refresh interval setting
+     * @param defaultRefreshInterval value of cluster default index refresh interval setting
+     */
+    private static void validateRefreshIntervalSettings(TimeValue minimumRefreshInterval, TimeValue defaultRefreshInterval) {
+        if (minimumRefreshInterval.compareTo(defaultRefreshInterval) > 0) {
+            throw new IllegalArgumentException(
+                "cluster minimum index refresh interval ["
+                    + minimumRefreshInterval
+                    + "] more than cluster default index refresh interval ["
+                    + defaultRefreshInterval
+                    + "]"
+            );
+        }
+    }
+
+    private TimeValue getClusterDefaultRefreshInterval() {
+        return this.clusterDefaultRefreshInterval;
+    }
+
+    // Exclusively for testing, please do not use it elsewhere.
+    public TimeValue getClusterRemoteTranslogBufferInterval() {
+        return clusterRemoteTranslogBufferInterval;
+    }
+
+    private void setClusterRemoteTranslogBufferInterval(TimeValue clusterRemoteTranslogBufferInterval) {
+        this.clusterRemoteTranslogBufferInterval = clusterRemoteTranslogBufferInterval;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/indices/InvalidAliasNameException.java b/server/src/main/java/org/opensearch/indices/InvalidAliasNameException.java
index 3658ffe8e588b..4ccb778c7010f 100644
--- a/server/src/main/java/org/opensearch/indices/InvalidAliasNameException.java
+++ b/server/src/main/java/org/opensearch/indices/InvalidAliasNameException.java
@@ -33,12 +33,17 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an alias name is invalid
+ *
+ * @opensearch.internal
+ */
 public class InvalidAliasNameException extends OpenSearchException {
 
     public InvalidAliasNameException(Index index, String name, String desc) {
diff --git a/server/src/main/java/org/opensearch/indices/InvalidIndexNameException.java b/server/src/main/java/org/opensearch/indices/InvalidIndexNameException.java
index b9df6569ebbf3..0d26a927bade5 100644
--- a/server/src/main/java/org/opensearch/indices/InvalidIndexNameException.java
+++ b/server/src/main/java/org/opensearch/indices/InvalidIndexNameException.java
@@ -33,12 +33,17 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an index name is invalid
+ *
+ * @opensearch.internal
+ */
 public class InvalidIndexNameException extends OpenSearchException {
 
     public InvalidIndexNameException(String name, String desc) {
diff --git a/server/src/main/java/org/opensearch/indices/InvalidIndexTemplateException.java b/server/src/main/java/org/opensearch/indices/InvalidIndexTemplateException.java
index 3ecbfe1e70edd..e5cce1a9c4487 100644
--- a/server/src/main/java/org/opensearch/indices/InvalidIndexTemplateException.java
+++ b/server/src/main/java/org/opensearch/indices/InvalidIndexTemplateException.java
@@ -32,12 +32,17 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if an index template is invalid
+ *
+ * @opensearch.internal
+ */
 public class InvalidIndexTemplateException extends OpenSearchException {
 
     private final String name;
diff --git a/server/src/main/java/org/opensearch/indices/InvalidTypeNameException.java b/server/src/main/java/org/opensearch/indices/InvalidTypeNameException.java
index d240cf6f83ff7..2cb1ce74d857d 100644
--- a/server/src/main/java/org/opensearch/indices/InvalidTypeNameException.java
+++ b/server/src/main/java/org/opensearch/indices/InvalidTypeNameException.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.indices;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.mapper.MapperException;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a type is invalid
+ *
+ * @opensearch.internal
+ */
 public class InvalidTypeNameException extends MapperException {
 
     public InvalidTypeNameException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/indices/NodeIndicesStats.java b/server/src/main/java/org/opensearch/indices/NodeIndicesStats.java
index 8e89894cbc78e..8a7aaba2726f4 100644
--- a/server/src/main/java/org/opensearch/indices/NodeIndicesStats.java
+++ b/server/src/main/java/org/opensearch/indices/NodeIndicesStats.java
@@ -35,13 +35,14 @@
 import org.opensearch.action.admin.indices.stats.CommonStats;
 import org.opensearch.action.admin.indices.stats.IndexShardStats;
 import org.opensearch.action.admin.indices.stats.ShardStats;
+import org.opensearch.action.search.SearchRequestStats;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.cache.request.RequestCacheStats;
 import org.opensearch.index.engine.SegmentsStats;
@@ -67,9 +68,10 @@
 
 /**
  * Global information on indices stats running on a specific node.
+ *
+ * @opensearch.internal
  */
 public class NodeIndicesStats implements Writeable, ToXContentFragment {
-
     private CommonStats stats;
     private Map<Index, List<IndexShardStats>> statsByShard;
 
@@ -90,7 +92,7 @@ public NodeIndicesStats(StreamInput in) throws IOException {
         }
     }
 
-    public NodeIndicesStats(CommonStats oldStats, Map<Index, List<IndexShardStats>> statsByShard) {
+    public NodeIndicesStats(CommonStats oldStats, Map<Index, List<IndexShardStats>> statsByShard, SearchRequestStats searchRequestStats) {
         // this.stats = stats;
         this.statsByShard = statsByShard;
 
@@ -103,6 +105,9 @@ public NodeIndicesStats(CommonStats oldStats, Map<Index, List<IndexShardStats>>
                 }
             }
         }
+        if (this.stats.search != null) {
+            this.stats.search.setSearchRequestStats(searchRequestStats);
+        }
     }
 
     @Nullable
@@ -269,6 +274,11 @@ public List<IndexShardStats> getShardStats(Index index) {
         }
     }
 
+    /**
+     * Fields used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String INDICES = "indices";
     }
diff --git a/server/src/main/java/org/opensearch/indices/RunUnderPrimaryPermit.java b/server/src/main/java/org/opensearch/indices/RunUnderPrimaryPermit.java
new file mode 100644
index 0000000000000..683bb51f64c1d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/RunUnderPrimaryPermit.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardRelocatedException;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Execute a Runnable after acquiring the primary's operation permit.
+ *
+ * @opensearch.internal
+ */
+public final class RunUnderPrimaryPermit {
+
+    public static void run(
+        CancellableThreads.Interruptible runnable,
+        String reason,
+        IndexShard primary,
+        CancellableThreads cancellableThreads,
+        Logger logger
+    ) {
+        cancellableThreads.execute(() -> {
+            CompletableFuture<Releasable> permit = new CompletableFuture<>();
+            final ActionListener<Releasable> onAcquired = new ActionListener<>() {
+                @Override
+                public void onResponse(Releasable releasable) {
+                    if (permit.complete(releasable) == false) {
+                        releasable.close();
+                    }
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    permit.completeExceptionally(e);
+                }
+            };
+            primary.acquirePrimaryOperationPermit(onAcquired, ThreadPool.Names.SAME, reason);
+            try (Releasable ignored = FutureUtils.get(permit)) {
+                // check that the IndexShard still has the primary authority. This needs to be checked under operation permit to prevent
+                // races, as IndexShard will switch its authority only when it holds all operation permits, see IndexShard.relocated()
+                if (primary.isRelocatedPrimary()) {
+                    throw new IndexShardRelocatedException(primary.shardId());
+                }
+                runnable.run();
+            } finally {
+                // just in case we got an exception (likely interrupted) while waiting for the get
+                permit.whenComplete((r, e) -> {
+                    if (r != null) {
+                        r.close();
+                    }
+                    if (e != null) {
+                        logger.trace("suppressing exception on completion (it was already bubbled up or the operation was aborted)", e);
+                    }
+                });
+            }
+        });
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/ShardLimitValidator.java b/server/src/main/java/org/opensearch/indices/ShardLimitValidator.java
index 3ed0dbee59e71..d9a64781c3f46 100644
--- a/server/src/main/java/org/opensearch/indices/ShardLimitValidator.java
+++ b/server/src/main/java/org/opensearch/indices/ShardLimitValidator.java
@@ -33,14 +33,19 @@
 package org.opensearch.indices;
 
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.ValidationException;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -53,26 +58,61 @@
  * NOTE: This is the limit applied at *shard creation time*. If you are looking for the limit applied at *allocation* time, which is
  * controlled by a different setting,
  * see {@link org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider}.
+ *
+ * @opensearch.internal
  */
 public class ShardLimitValidator {
+
+    public static final String SETTING_MAX_SHARDS_PER_CLUSTER_KEY = "cluster.routing.allocation.total_shards_limit";
     public static final Setting<Integer> SETTING_CLUSTER_MAX_SHARDS_PER_NODE = Setting.intSetting(
         "cluster.max_shards_per_node",
         1000,
         1,
+        new MaxShardPerNodeLimitValidator(),
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Integer> SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER = Setting.intSetting(
+        SETTING_MAX_SHARDS_PER_CLUSTER_KEY,
+        -1,
+        -1,
+        new MaxShardPerClusterLimitValidator(),
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Boolean> SETTING_CLUSTER_IGNORE_DOT_INDEXES = Setting.boolSetting(
+        "cluster.ignore_dot_indexes",
+        false,
         Setting.Property.Dynamic,
         Setting.Property.NodeScope
     );
+
     protected final AtomicInteger shardLimitPerNode = new AtomicInteger();
+    protected final AtomicInteger shardLimitPerCluster = new AtomicInteger();
+    private final SystemIndices systemIndices;
+    private volatile boolean ignoreDotIndexes;
 
-    public ShardLimitValidator(final Settings settings, ClusterService clusterService) {
+    public ShardLimitValidator(final Settings settings, ClusterService clusterService, SystemIndices systemIndices) {
         this.shardLimitPerNode.set(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.get(settings));
+        this.shardLimitPerCluster.set(SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER.get(settings));
+        this.ignoreDotIndexes = SETTING_CLUSTER_IGNORE_DOT_INDEXES.get(settings);
         clusterService.getClusterSettings().addSettingsUpdateConsumer(SETTING_CLUSTER_MAX_SHARDS_PER_NODE, this::setShardLimitPerNode);
+        clusterService.getClusterSettings()
+            .addSettingsUpdateConsumer(SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER, this::setShardLimitPerCluster);
+        clusterService.getClusterSettings().addSettingsUpdateConsumer(SETTING_CLUSTER_IGNORE_DOT_INDEXES, this::setIgnoreDotIndexes);
+        this.systemIndices = systemIndices;
     }
 
     private void setShardLimitPerNode(int newValue) {
         this.shardLimitPerNode.set(newValue);
     }
 
+    private void setShardLimitPerCluster(int newValue) {
+        this.shardLimitPerCluster.set(newValue);
+    }
+
     /**
      * Gets the currently configured value of the {@link ShardLimitValidator#SETTING_CLUSTER_MAX_SHARDS_PER_NODE} setting.
      * @return the current value of the setting
@@ -81,14 +121,39 @@ public int getShardLimitPerNode() {
         return shardLimitPerNode.get();
     }
 
+    /**
+     * Gets the currently configured value of the {@link ShardLimitValidator#SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER} setting.
+     * @return the current value of the setting.
+     */
+    public int getShardLimitPerCluster() {
+        return shardLimitPerCluster.get();
+    }
+
+    private void setIgnoreDotIndexes(boolean newValue) {
+        this.ignoreDotIndexes = newValue;
+    }
+
     /**
      * Checks whether an index can be created without going over the cluster shard limit.
+     * Validate shard limit only for non system indices as it is not hard limit anyways.
+     * Further also validates if the cluster.ignore_dot_indexes is set to true.
+     * If so then it does not validate any index which starts with '.' except data-stream index.
      *
+     * @param indexName      the name of the index being created
      * @param settings       the settings of the index to be created
      * @param state          the current cluster state
      * @throws ValidationException if creating this index would put the cluster over the cluster shard limit
      */
-    public void validateShardLimit(final Settings settings, final ClusterState state) {
+    public void validateShardLimit(final String indexName, final Settings settings, final ClusterState state) {
+        /*
+        Validate shard limit only for non system indices as it is not hard limit anyways.
+        Further also validates if the cluster.ignore_dot_indexes is set to true.
+        If so then it does not validate any index which starts with '.'.
+        */
+        if (shouldIndexBeIgnored(indexName)) {
+            return;
+        }
+
         final int numberOfShards = INDEX_NUMBER_OF_SHARDS_SETTING.get(settings);
         final int numberOfReplicas = IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.get(settings);
         final int shardsToCreate = numberOfShards * (1 + numberOfReplicas);
@@ -103,7 +168,9 @@ public void validateShardLimit(final Settings settings, final ClusterState state
 
     /**
      * Validates whether a list of indices can be opened without going over the cluster shard limit.  Only counts indices which are
-     * currently closed and will be opened, ignores indices which are already open.
+     * currently closed and will be opened, ignores indices which are already open. Adding to this it validates the
+     * shard limit only for non system indices and if the cluster.ignore_dot_indexes property is set to true
+     * then the indexes starting with '.' are ignored except the data-stream indexes.
      *
      * @param currentState The current cluster state.
      * @param indicesToOpen The indices which are to be opened.
@@ -111,6 +178,13 @@ public void validateShardLimit(final Settings settings, final ClusterState state
      */
     public void validateShardLimit(ClusterState currentState, Index[] indicesToOpen) {
         int shardsToOpen = Arrays.stream(indicesToOpen)
+            /*
+            Validate shard limit only for non system indices as it is not hard limit anyways.
+            Further also validates if the cluster.ignore_dot_indexes is set to true.
+            If so then it does not validate any index which starts with '.'
+            however data-stream indexes are still validated.
+            */
+            .filter(index -> !shouldIndexBeIgnored(index.getName()))
             .filter(index -> currentState.metadata().index(index).getState().equals(IndexMetadata.State.CLOSE))
             .mapToInt(index -> getTotalShardCount(currentState, index))
             .sum();
@@ -128,6 +202,37 @@ private static int getTotalShardCount(ClusterState state, Index index) {
         return indexMetadata.getNumberOfShards() * (1 + indexMetadata.getNumberOfReplicas());
     }
 
+    /**
+     * Returns true if the index should be ignored during validation.
+     * Index is ignored if it is a system index or if cluster.ignore_dot_indexes is set to true
+     * then indexes which are starting with dot and are not data stream index are ignored.
+     *
+     * @param indexName  The index which needs to be validated.
+     */
+    private boolean shouldIndexBeIgnored(String indexName) {
+        if (this.ignoreDotIndexes) {
+            return validateDotIndex(indexName) && !isDataStreamIndex(indexName);
+        } else return systemIndices.validateSystemIndex(indexName);
+    }
+
+    /**
+     * Returns true if the index name starts with '.' else false.
+     *
+     * @param indexName  The index which needs to be validated.
+     */
+    private boolean validateDotIndex(String indexName) {
+        return indexName.charAt(0) == '.';
+    }
+
+    /**
+     * Returns true if the index is dataStreamIndex false otherwise.
+     *
+     * @param indexName  The index which needs to be validated.
+     */
+    private boolean isDataStreamIndex(String indexName) {
+        return indexName.startsWith(DataStream.BACKING_INDEX_PREFIX);
+    }
+
     /**
      * Checks to see if an operation can be performed without taking the cluster over the cluster-wide shard limit.
      * Returns an error message if appropriate, or an empty {@link Optional} otherwise.
@@ -138,11 +243,16 @@ private static int getTotalShardCount(ClusterState state, Index index) {
      * an operation. If empty, a sign that the operation is valid.
      */
     public Optional<String> checkShardLimit(int newShards, ClusterState state) {
-        return checkShardLimit(newShards, state, getShardLimitPerNode());
+        return checkShardLimit(newShards, state, getShardLimitPerNode(), getShardLimitPerCluster());
     }
 
     // package-private for testing
-    static Optional<String> checkShardLimit(int newShards, ClusterState state, int maxShardsPerNodeSetting) {
+    static Optional<String> checkShardLimit(
+        int newShards,
+        ClusterState state,
+        int maxShardsPerNodeSetting,
+        int maxShardsPerClusterSetting
+    ) {
         int nodeCount = state.getNodes().getDataNodes().size();
 
         // Only enforce the shard limit if we have at least one data node, so that we don't block
@@ -150,10 +260,15 @@ static Optional<String> checkShardLimit(int newShards, ClusterState state, int m
         if (nodeCount == 0 || newShards < 0) {
             return Optional.empty();
         }
-        int maxShardsPerNode = maxShardsPerNodeSetting;
-        int maxShardsInCluster = maxShardsPerNode * nodeCount;
-        int currentOpenShards = state.getMetadata().getTotalOpenIndexShards();
 
+        int maxShardsInCluster = maxShardsPerClusterSetting;
+        if (maxShardsInCluster == -1) {
+            maxShardsInCluster = maxShardsPerNodeSetting * nodeCount;
+        } else {
+            maxShardsInCluster = Math.min(maxShardsInCluster, maxShardsPerNodeSetting * nodeCount);
+        }
+
+        int currentOpenShards = state.getMetadata().getTotalOpenIndexShards();
         if ((currentOpenShards + newShards) > maxShardsInCluster) {
             String errorMessage = "this action would add ["
                 + newShards
@@ -166,4 +281,54 @@ static Optional<String> checkShardLimit(int newShards, ClusterState state, int m
         }
         return Optional.empty();
     }
+
+    /**
+     * Validates the MaxShadPerCluster threshold.
+     */
+    static final class MaxShardPerClusterLimitValidator implements Setting.Validator<Integer> {
+
+        @Override
+        public void validate(Integer value) {}
+
+        @Override
+        public void validate(Integer maxShardPerCluster, Map<Setting<?>, Object> settings) {
+            final int maxShardPerNode = (int) settings.get(SETTING_CLUSTER_MAX_SHARDS_PER_NODE);
+            doValidate(maxShardPerCluster, maxShardPerNode);
+        }
+
+        @Override
+        public Iterator<Setting<?>> settings() {
+            final List<Setting<?>> settings = Collections.singletonList(SETTING_CLUSTER_MAX_SHARDS_PER_NODE);
+            return settings.iterator();
+        }
+    }
+
+    /**
+     * Validates the MaxShadPerNode threshold.
+     */
+    static final class MaxShardPerNodeLimitValidator implements Setting.Validator<Integer> {
+
+        @Override
+        public void validate(Integer value) {}
+
+        @Override
+        public void validate(Integer maxShardPerNode, Map<Setting<?>, Object> settings) {
+            final int maxShardPerCluster = (int) settings.get(SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER);
+            doValidate(maxShardPerCluster, maxShardPerNode);
+        }
+
+        @Override
+        public Iterator<Setting<?>> settings() {
+            final List<Setting<?>> settings = Collections.singletonList(SETTING_CLUSTER_MAX_SHARDS_PER_CLUSTER);
+            return settings.iterator();
+        }
+    }
+
+    private static void doValidate(final int maxShardPerCluster, final int maxShardPerNode) {
+        if (maxShardPerCluster != -1 && maxShardPerCluster < maxShardPerNode) {
+            throw new IllegalArgumentException(
+                "MaxShardPerCluster " + maxShardPerCluster + " should be greater than or equal to MaxShardPerNode " + maxShardPerNode
+            );
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/indices/SystemIndexDescriptor.java b/server/src/main/java/org/opensearch/indices/SystemIndexDescriptor.java
index 9e41fe8943474..f3592a3561d3a 100644
--- a/server/src/main/java/org/opensearch/indices/SystemIndexDescriptor.java
+++ b/server/src/main/java/org/opensearch/indices/SystemIndexDescriptor.java
@@ -39,6 +39,8 @@
 
 /**
  * Describes a system index. Provides the information required to create and maintain the system index.
+ *
+ * @opensearch.internal
  */
 public class SystemIndexDescriptor {
     private final String indexPattern;
diff --git a/server/src/main/java/org/opensearch/indices/SystemIndices.java b/server/src/main/java/org/opensearch/indices/SystemIndices.java
index fc34645b4326f..a85e938c61b7a 100644
--- a/server/src/main/java/org/opensearch/indices/SystemIndices.java
+++ b/server/src/main/java/org/opensearch/indices/SystemIndices.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.indices;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.CharacterRunAutomaton;
@@ -40,7 +42,7 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.tasks.TaskResultsService;
 
 import java.util.Collection;
@@ -61,8 +63,12 @@
  * This class holds the {@link SystemIndexDescriptor} objects that represent system indices the
  * node knows about. Methods for determining if an index should be a system index are also provided
  * to reduce the locations within the code that need to deal with {@link SystemIndexDescriptor}s.
+ *
+ * @opensearch.internal
  */
 public class SystemIndices {
+    private static final Logger logger = LogManager.getLogger(SystemIndices.class);
+
     private static final Map<String, Collection<SystemIndexDescriptor>> SERVER_SYSTEM_INDEX_DESCRIPTORS = singletonMap(
         TaskResultsService.class.getName(),
         singletonList(new SystemIndexDescriptor(TASK_INDEX + "*", "Task Result Index"))
@@ -135,6 +141,27 @@ public boolean isSystemIndex(String indexName) {
         }
     }
 
+    /**
+     * Validates (if this index has a dot-prefixed name) and it is system index.
+     * @param index The name of the index in question
+     */
+    public boolean validateSystemIndex(String index) {
+        if (index.charAt(0) == '.') {
+            SystemIndexDescriptor matchingDescriptor = findMatchingDescriptor(index);
+            if (matchingDescriptor != null) {
+                logger.trace(
+                    "index [{}] is a system index because it matches index pattern [{}] with description [{}]",
+                    index,
+                    matchingDescriptor.getIndexPattern(),
+                    matchingDescriptor.getDescription()
+                );
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     private static CharacterRunAutomaton buildCharacterRunAutomaton(Collection<SystemIndexDescriptor> descriptors) {
         Optional<Automaton> automaton = descriptors.stream()
             .map(descriptor -> Regex.simpleMatchToAutomaton(descriptor.getIndexPattern()))
diff --git a/server/src/main/java/org/opensearch/indices/TermsLookup.java b/server/src/main/java/org/opensearch/indices/TermsLookup.java
index bf6c024fa130e..37533c0809d7a 100644
--- a/server/src/main/java/org/opensearch/indices/TermsLookup.java
+++ b/server/src/main/java/org/opensearch/indices/TermsLookup.java
@@ -33,24 +33,26 @@
 package org.opensearch.indices;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.TermsQueryBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * Encapsulates the parameters needed to fetch terms.
+ *
+ * @opensearch.internal
  */
 public class TermsLookup implements Writeable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/indices/TypeMissingException.java b/server/src/main/java/org/opensearch/indices/TypeMissingException.java
index 3392979fdbc0d..c74572f6900c7 100644
--- a/server/src/main/java/org/opensearch/indices/TypeMissingException.java
+++ b/server/src/main/java/org/opensearch/indices/TypeMissingException.java
@@ -33,13 +33,21 @@
 package org.opensearch.indices;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Arrays;
 
+/**
+ * Exception thrown if a document type is missing
+ *
+ * @opensearch.internal
+ *
+ * @deprecated Types are removed
+ */
+@Deprecated
 public class TypeMissingException extends OpenSearchException {
 
     public TypeMissingException(Index index, String... types) {
diff --git a/server/src/main/java/org/opensearch/indices/analysis/AnalysisModule.java b/server/src/main/java/org/opensearch/indices/analysis/AnalysisModule.java
index 5d43bfa8876c8..cc87c982a684d 100644
--- a/server/src/main/java/org/opensearch/indices/analysis/AnalysisModule.java
+++ b/server/src/main/java/org/opensearch/indices/analysis/AnalysisModule.java
@@ -74,6 +74,8 @@
 
 /**
  * Sets up {@link AnalysisRegistry}.
+ *
+ * @opensearch.internal
  */
 public final class AnalysisModule {
     static {
diff --git a/server/src/main/java/org/opensearch/indices/analysis/HunspellService.java b/server/src/main/java/org/opensearch/indices/analysis/HunspellService.java
index 08f8b18920eb9..09cdccf4b04cb 100644
--- a/server/src/main/java/org/opensearch/indices/analysis/HunspellService.java
+++ b/server/src/main/java/org/opensearch/indices/analysis/HunspellService.java
@@ -38,11 +38,11 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.NIOFSDirectory;
 import org.opensearch.OpenSearchException;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.env.Environment;
 
 import java.io.IOException;
@@ -87,6 +87,8 @@
  * </code></pre>
  *
  * @see org.opensearch.index.analysis.HunspellTokenFilterFactory
+ *
+ * @opensearch.internal
  */
 public class HunspellService {
 
@@ -121,7 +123,8 @@ public HunspellService(final Settings settings, final Environment env, final Map
             try {
                 return loadDictionary(locale, settings, env);
             } catch (Exception e) {
-                throw new IllegalStateException("failed to load hunspell dictionary for locale: " + locale, e);
+                logger.error("Failed to load hunspell dictionary for locale: " + locale, e);
+                throw new IllegalStateException("Failed to load hunspell dictionary for locale: " + locale);
             }
         };
         if (!HUNSPELL_LAZY_LOAD.get(settings)) {
diff --git a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltAnalyzers.java b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltAnalyzers.java
index 640100bbcc082..fad9c7d6c61cc 100644
--- a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltAnalyzers.java
+++ b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltAnalyzers.java
@@ -45,6 +45,11 @@
 
 import java.util.Locale;
 
+/**
+ * Pre built analyzers
+ *
+ * @opensearch.internal
+ */
 public enum PreBuiltAnalyzers {
 
     STANDARD(CachingStrategy.OPENSEARCH) {
diff --git a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltCacheFactory.java b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltCacheFactory.java
index f53c1b5568584..601bd79a24746 100644
--- a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltCacheFactory.java
+++ b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltCacheFactory.java
@@ -39,6 +39,11 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * A factory for the pre-built cache
+ *
+ * @opensearch.internal
+ */
 public class PreBuiltCacheFactory {
 
     /**
@@ -55,6 +60,11 @@ public enum CachingStrategy {
         OPENSEARCH
     }
 
+    /**
+     * The prebuilt cache
+     *
+     * @opensearch.internal
+     */
     public interface PreBuiltCache<T> {
 
         T get(Version version);
@@ -81,6 +91,8 @@ public static <T> PreBuiltCache<T> getCache(CachingStrategy cachingStrategy) {
 
     /**
      * This is a pretty simple cache, it only contains one version
+     *
+     * @opensearch.internal
      */
     private static class PreBuiltCacheStrategyOne<T> implements PreBuiltCache<T> {
 
@@ -104,6 +116,8 @@ public Collection<T> values() {
 
     /**
      * This cache contains one version for each opensearch version object
+     *
+     * @opensearch.internal
      */
     private static class PreBuiltCacheStrategyOpenSearch<T> implements PreBuiltCache<T> {
 
@@ -127,6 +141,8 @@ public Collection<T> values() {
 
     /**
      * This cache uses the lucene version for caching
+     *
+     * @opensearch.internal
      */
     private static class PreBuiltCacheStrategyLucene<T> implements PreBuiltCache<T> {
 
diff --git a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltTokenizers.java b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltTokenizers.java
index 3499e63501efd..c68f8fe6c3ba5 100644
--- a/server/src/main/java/org/opensearch/indices/analysis/PreBuiltTokenizers.java
+++ b/server/src/main/java/org/opensearch/indices/analysis/PreBuiltTokenizers.java
@@ -37,6 +37,11 @@
 import org.opensearch.index.analysis.TokenFilterFactory;
 import org.opensearch.indices.analysis.PreBuiltCacheFactory.CachingStrategy;
 
+/**
+ * Pre-built tokenizers for analysis
+ *
+ * @opensearch.internal
+ */
 public enum PreBuiltTokenizers {
 
     STANDARD(CachingStrategy.ONE) {
diff --git a/server/src/main/java/org/opensearch/indices/analysis/package-info.java b/server/src/main/java/org/opensearch/indices/analysis/package-info.java
new file mode 100644
index 0000000000000..3f4103298b04e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/analysis/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Analysis Module package. */
+package org.opensearch.indices.analysis;
diff --git a/server/src/main/java/org/opensearch/indices/breaker/AllCircuitBreakerStats.java b/server/src/main/java/org/opensearch/indices/breaker/AllCircuitBreakerStats.java
deleted file mode 100644
index 4c737774fc42e..0000000000000
--- a/server/src/main/java/org/opensearch/indices/breaker/AllCircuitBreakerStats.java
+++ /dev/null
@@ -1,91 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.breaker;
-
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-
-import java.io.IOException;
-
-/**
- * Stats class encapsulating all of the different circuit breaker stats
- */
-public class AllCircuitBreakerStats implements Writeable, ToXContentFragment {
-
-    private final CircuitBreakerStats[] allStats;
-
-    public AllCircuitBreakerStats(CircuitBreakerStats[] allStats) {
-        this.allStats = allStats;
-    }
-
-    public AllCircuitBreakerStats(StreamInput in) throws IOException {
-        allStats = in.readArray(CircuitBreakerStats::new, CircuitBreakerStats[]::new);
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeArray(allStats);
-    }
-
-    public CircuitBreakerStats[] getAllStats() {
-        return this.allStats;
-    }
-
-    public CircuitBreakerStats getStats(String name) {
-        for (CircuitBreakerStats stats : allStats) {
-            if (stats.getName().equals(name)) {
-                return stats;
-            }
-        }
-        return null;
-    }
-
-    @Override
-    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        builder.startObject(Fields.BREAKERS);
-        for (CircuitBreakerStats stats : allStats) {
-            if (stats != null) {
-                stats.toXContent(builder, params);
-            }
-        }
-        builder.endObject();
-        return builder;
-    }
-
-    static final class Fields {
-        static final String BREAKERS = "breakers";
-    }
-}
diff --git a/server/src/main/java/org/opensearch/indices/breaker/BreakerSettings.java b/server/src/main/java/org/opensearch/indices/breaker/BreakerSettings.java
index 97c851e036778..e1ed346bfcb17 100644
--- a/server/src/main/java/org/opensearch/indices/breaker/BreakerSettings.java
+++ b/server/src/main/java/org/opensearch/indices/breaker/BreakerSettings.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.indices.breaker;
 
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 /**
  * Settings for a {@link CircuitBreaker}
+ *
+ * @opensearch.internal
  */
 public final class BreakerSettings {
 
diff --git a/server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerStats.java b/server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerStats.java
deleted file mode 100644
index 4c67e4ce21a33..0000000000000
--- a/server/src/main/java/org/opensearch/indices/breaker/CircuitBreakerStats.java
+++ /dev/null
@@ -1,141 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.breaker;
-
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-
-import java.io.IOException;
-import java.util.Locale;
-
-/**
- * Class encapsulating stats about the circuit breaker
- */
-public class CircuitBreakerStats implements Writeable, ToXContentObject {
-
-    private final String name;
-    private final long limit;
-    private final long estimated;
-    private final long trippedCount;
-    private final double overhead;
-
-    public CircuitBreakerStats(String name, long limit, long estimated, double overhead, long trippedCount) {
-        this.name = name;
-        this.limit = limit;
-        this.estimated = estimated;
-        this.trippedCount = trippedCount;
-        this.overhead = overhead;
-    }
-
-    public CircuitBreakerStats(StreamInput in) throws IOException {
-        this.limit = in.readLong();
-        this.estimated = in.readLong();
-        this.overhead = in.readDouble();
-        this.trippedCount = in.readLong();
-        this.name = in.readString();
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeLong(limit);
-        out.writeLong(estimated);
-        out.writeDouble(overhead);
-        out.writeLong(trippedCount);
-        out.writeString(name);
-    }
-
-    public String getName() {
-        return this.name;
-    }
-
-    public long getLimit() {
-        return this.limit;
-    }
-
-    public long getEstimated() {
-        return this.estimated;
-    }
-
-    public long getTrippedCount() {
-        return this.trippedCount;
-    }
-
-    public double getOverhead() {
-        return this.overhead;
-    }
-
-    @Override
-    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        builder.startObject(name.toLowerCase(Locale.ROOT));
-        builder.field(Fields.LIMIT, limit);
-        builder.field(Fields.LIMIT_HUMAN, new ByteSizeValue(limit));
-        builder.field(Fields.ESTIMATED, estimated);
-        builder.field(Fields.ESTIMATED_HUMAN, new ByteSizeValue(estimated));
-        builder.field(Fields.OVERHEAD, overhead);
-        builder.field(Fields.TRIPPED_COUNT, trippedCount);
-        builder.endObject();
-        return builder;
-    }
-
-    @Override
-    public String toString() {
-        return "["
-            + this.name
-            + ",limit="
-            + this.limit
-            + "/"
-            + new ByteSizeValue(this.limit)
-            + ",estimated="
-            + this.estimated
-            + "/"
-            + new ByteSizeValue(this.estimated)
-            + ",overhead="
-            + this.overhead
-            + ",tripped="
-            + this.trippedCount
-            + "]";
-    }
-
-    static final class Fields {
-        static final String LIMIT = "limit_size_in_bytes";
-        static final String LIMIT_HUMAN = "limit_size";
-        static final String ESTIMATED = "estimated_size_in_bytes";
-        static final String ESTIMATED_HUMAN = "estimated_size";
-        static final String OVERHEAD = "overhead";
-        static final String TRIPPED_COUNT = "tripped";
-    }
-}
diff --git a/server/src/main/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerService.java b/server/src/main/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerService.java
index ec5d1edf3c448..a5aceead1062f 100644
--- a/server/src/main/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerService.java
+++ b/server/src/main/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerService.java
@@ -37,17 +37,20 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.breaker.ChildMemoryCircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.AllCircuitBreakerStats;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.CircuitBreakerStats;
 import org.opensearch.monitor.jvm.GcNames;
 import org.opensearch.monitor.jvm.JvmInfo;
 
@@ -71,6 +74,8 @@
 /**
  * CircuitBreakerService that attempts to redistribute space between breakers
  * if tripped
+ *
+ * @opensearch.internal
  */
 public class HierarchyCircuitBreakerService extends CircuitBreakerService {
     private static final Logger logger = LogManager.getLogger(HierarchyCircuitBreakerService.class);
@@ -339,6 +344,11 @@ public CircuitBreakerStats stats(String name) {
         );
     }
 
+    /**
+     * Tracks memory usage
+     *
+     * @opensearch.internal
+     */
     static class MemoryUsage {
         final long baseUsage;
         final long totalUsage;
@@ -503,6 +513,11 @@ interface OverLimitStrategy {
         MemoryUsage overLimit(MemoryUsage memoryUsed);
     }
 
+    /**
+     * Kicks in G1GC if heap gets too high
+     *
+     * @opensearch.internal
+     */
     static class G1OverLimitStrategy implements OverLimitStrategy {
         private final long g1RegionSize;
         private final LongSupplier currentMemoryUsageSupplier;
@@ -547,8 +562,19 @@ static long fallbackRegionSize(JvmInfo jvmInfo) {
             // https://hg.openjdk.java.net/jdk/jdk/file/e7d0ec2d06e8/src/hotspot/share/gc/g1/heapRegion.cpp#l67
             // based on this JDK "bug":
             // https://bugs.openjdk.java.net/browse/JDK-8241670
-            long averageHeapSize = (jvmInfo.getMem().getHeapMax().getBytes() + JvmInfo.jvmInfo().getMem().getHeapMax().getBytes()) / 2;
-            long regionSize = Long.highestOneBit(averageHeapSize / 2048);
+            // JDK-17 updates:
+            // https://github.com/openjdk/jdk17u/blob/master/src/hotspot/share/gc/g1/heapRegionBounds.hpp
+            // https://github.com/openjdk/jdk17u/blob/master/src/hotspot/share/gc/g1/heapRegion.cpp#L67
+            long regionSizeUnrounded = Math.min(
+                Math.max(JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() / 2048, ByteSizeUnit.MB.toBytes(1)),
+                ByteSizeUnit.MB.toBytes(32)
+            );
+
+            long regionSize = Long.highestOneBit(regionSizeUnrounded);
+            if (regionSize != regionSizeUnrounded) {
+                regionSize <<= 1; /* next power of 2 */
+            }
+
             if (regionSize < ByteSizeUnit.MB.toBytes(1)) {
                 regionSize = ByteSizeUnit.MB.toBytes(1);
             } else if (regionSize > ByteSizeUnit.MB.toBytes(32)) {
diff --git a/server/src/main/java/org/opensearch/indices/breaker/NoneCircuitBreakerService.java b/server/src/main/java/org/opensearch/indices/breaker/NoneCircuitBreakerService.java
deleted file mode 100644
index ef77598b20009..0000000000000
--- a/server/src/main/java/org/opensearch/indices/breaker/NoneCircuitBreakerService.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.breaker;
-
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
-
-/**
- * Class that returns a breaker that never breaks
- */
-public class NoneCircuitBreakerService extends CircuitBreakerService {
-
-    private final CircuitBreaker breaker = new NoopCircuitBreaker(CircuitBreaker.FIELDDATA);
-
-    public NoneCircuitBreakerService() {
-        super();
-    }
-
-    @Override
-    public CircuitBreaker getBreaker(String name) {
-        return breaker;
-    }
-
-    @Override
-    public AllCircuitBreakerStats stats() {
-        return new AllCircuitBreakerStats(new CircuitBreakerStats[] { stats(CircuitBreaker.FIELDDATA) });
-    }
-
-    @Override
-    public CircuitBreakerStats stats(String name) {
-        return new CircuitBreakerStats(CircuitBreaker.FIELDDATA, -1, -1, 0, 0);
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/indices/breaker/package-info.java b/server/src/main/java/org/opensearch/indices/breaker/package-info.java
new file mode 100644
index 0000000000000..9e455c0a54c15
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/breaker/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** CircuitBreaker Service package. */
+package org.opensearch.indices.breaker;
diff --git a/server/src/main/java/org/opensearch/indices/cluster/IndicesClusterStateService.java b/server/src/main/java/org/opensearch/indices/cluster/IndicesClusterStateService.java
index 9463b51ca3792..8a666c6b260b1 100644
--- a/server/src/main/java/org/opensearch/indices/cluster/IndicesClusterStateService.java
+++ b/server/src/main/java/org/opensearch/indices/cluster/IndicesClusterStateService.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ResourceAlreadyExistsException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateApplier;
@@ -52,18 +51,21 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.ShardLockObtainFailedException;
 import org.opensearch.gateway.GatewayService;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexComponent;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.seqno.GlobalCheckpointSyncAction;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
@@ -73,13 +75,16 @@
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
 import org.opensearch.index.shard.PrimaryReplicaSyncer.ResyncTask;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.recovery.PeerRecoverySourceService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
-import org.opensearch.indices.recovery.RecoveryFailedException;
+import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.SegmentReplicationSourceService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.ReplicationState;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.search.SearchService;
 import org.opensearch.snapshots.SnapshotShardsService;
@@ -88,6 +93,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -100,12 +106,18 @@
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
 import static org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.CLOSED;
 import static org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.DELETED;
 import static org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.FAILURE;
 import static org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.NO_LONGER_ASSIGNED;
 import static org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.REOPENED;
 
+/**
+ * Service to update the cluster state for multiple indices
+ *
+ * @opensearch.internal
+ */
 public class IndicesClusterStateService extends AbstractLifecycleComponent implements ClusterStateApplier {
     private static final Logger logger = LogManager.getLogger(IndicesClusterStateService.class);
 
@@ -127,11 +139,17 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent imple
     private final FailedShardHandler failedShardHandler = new FailedShardHandler();
 
     private final boolean sendRefreshMapping;
-    private final List<IndexEventListener> buildInIndexListener;
+    private final List<IndexEventListener> builtInIndexListener;
     private final PrimaryReplicaSyncer primaryReplicaSyncer;
     private final Consumer<ShardId> globalCheckpointSyncer;
     private final RetentionLeaseSyncer retentionLeaseSyncer;
 
+    private final SegmentReplicationTargetService segmentReplicationTargetService;
+
+    private final SegmentReplicationCheckpointPublisher checkpointPublisher;
+
+    private final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
     @Inject
     public IndicesClusterStateService(
         final Settings settings,
@@ -139,6 +157,8 @@ public IndicesClusterStateService(
         final ClusterService clusterService,
         final ThreadPool threadPool,
         final PeerRecoveryTargetService recoveryTargetService,
+        final SegmentReplicationTargetService segmentReplicationTargetService,
+        final SegmentReplicationSourceService segmentReplicationSourceService,
         final ShardStateAction shardStateAction,
         final NodeMappingRefreshAction nodeMappingRefreshAction,
         final RepositoriesService repositoriesService,
@@ -147,13 +167,18 @@ public IndicesClusterStateService(
         final SnapshotShardsService snapshotShardsService,
         final PrimaryReplicaSyncer primaryReplicaSyncer,
         final GlobalCheckpointSyncAction globalCheckpointSyncAction,
-        final RetentionLeaseSyncer retentionLeaseSyncer
+        final RetentionLeaseSyncer retentionLeaseSyncer,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
+        final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
     ) {
         this(
             settings,
             indicesService,
             clusterService,
             threadPool,
+            checkpointPublisher,
+            segmentReplicationTargetService,
+            segmentReplicationSourceService,
             recoveryTargetService,
             shardStateAction,
             nodeMappingRefreshAction,
@@ -163,7 +188,8 @@ public IndicesClusterStateService(
             snapshotShardsService,
             primaryReplicaSyncer,
             globalCheckpointSyncAction::updateGlobalCheckpointForShard,
-            retentionLeaseSyncer
+            retentionLeaseSyncer,
+            remoteStoreStatsTrackerFactory
         );
     }
 
@@ -173,6 +199,9 @@ public IndicesClusterStateService(
         final AllocatedIndices<? extends Shard, ? extends AllocatedIndex<? extends Shard>> indicesService,
         final ClusterService clusterService,
         final ThreadPool threadPool,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
+        final SegmentReplicationTargetService segmentReplicationTargetService,
+        final SegmentReplicationSourceService segmentReplicationSourceService,
         final PeerRecoveryTargetService recoveryTargetService,
         final ShardStateAction shardStateAction,
         final NodeMappingRefreshAction nodeMappingRefreshAction,
@@ -182,10 +211,20 @@ public IndicesClusterStateService(
         final SnapshotShardsService snapshotShardsService,
         final PrimaryReplicaSyncer primaryReplicaSyncer,
         final Consumer<ShardId> globalCheckpointSyncer,
-        final RetentionLeaseSyncer retentionLeaseSyncer
+        final RetentionLeaseSyncer retentionLeaseSyncer,
+        final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
     ) {
         this.settings = settings;
-        this.buildInIndexListener = Arrays.asList(peerRecoverySourceService, recoveryTargetService, searchService, snapshotShardsService);
+        this.checkpointPublisher = checkpointPublisher;
+
+        final List<IndexEventListener> indexEventListeners = new ArrayList<>(
+            Arrays.asList(peerRecoverySourceService, recoveryTargetService, searchService, snapshotShardsService)
+        );
+        indexEventListeners.add(segmentReplicationTargetService);
+        indexEventListeners.add(segmentReplicationSourceService);
+        indexEventListeners.add(remoteStoreStatsTrackerFactory);
+        this.segmentReplicationTargetService = segmentReplicationTargetService;
+        this.builtInIndexListener = Collections.unmodifiableList(indexEventListeners);
         this.indicesService = indicesService;
         this.clusterService = clusterService;
         this.threadPool = threadPool;
@@ -197,19 +236,20 @@ public IndicesClusterStateService(
         this.globalCheckpointSyncer = globalCheckpointSyncer;
         this.retentionLeaseSyncer = Objects.requireNonNull(retentionLeaseSyncer);
         this.sendRefreshMapping = settings.getAsBoolean("indices.cluster.send_refresh_mapping", true);
+        this.remoteStoreStatsTrackerFactory = remoteStoreStatsTrackerFactory;
     }
 
     @Override
     protected void doStart() {
         // Doesn't make sense to manage shards on non-master and non-data nodes
-        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isClusterManagerNode(settings)) {
             clusterService.addHighPriorityApplier(this);
         }
     }
 
     @Override
     protected void doStop() {
-        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isClusterManagerNode(settings)) {
             clusterService.removeApplier(this);
         }
     }
@@ -226,7 +266,7 @@ public synchronized void applyClusterState(final ClusterChangedEvent event) {
         final ClusterState state = event.state();
 
         // we need to clean the shards and indices we have on this node, since we
-        // are going to recover them again once state persistence is disabled (no master / not recovered)
+        // are going to recover them again once state persistence is disabled (no cluster-manager / not recovered)
         // TODO: feels hacky, a block disables state persistence, and then we clean the allocated shards, maybe another flag in blocks?
         if (state.blocks().disableStatePersistence()) {
             for (AllocatedIndex<? extends Shard> indexService : indicesService) {
@@ -244,7 +284,7 @@ public synchronized void applyClusterState(final ClusterChangedEvent event) {
 
         failMissingShards(state);
 
-        removeShards(state);   // removes any local shards that doesn't match what the master expects
+        removeShards(state);   // removes any local shards that doesn't match what the cluster-manager expects
 
         updateIndices(event); // can also fail shards, but these are then guaranteed to be in failedShardsCache
 
@@ -267,17 +307,21 @@ private void updateFailedShardsCache(final ClusterState state) {
             return;
         }
 
-        DiscoveryNode masterNode = state.nodes().getMasterNode();
+        DiscoveryNode clusterManagerNode = state.nodes().getClusterManagerNode();
 
-        // remove items from cache which are not in our routing table anymore and resend failures that have not executed on master yet
+        // remove items from cache which are not in our routing table anymore and
+        // resend failures that have not executed on cluster-manager yet
         for (Iterator<Map.Entry<ShardId, ShardRouting>> iterator = failedShardsCache.entrySet().iterator(); iterator.hasNext();) {
             ShardRouting failedShardRouting = iterator.next().getValue();
             ShardRouting matchedRouting = localRoutingNode.getByShardId(failedShardRouting.shardId());
             if (matchedRouting == null || matchedRouting.isSameAllocation(failedShardRouting) == false) {
                 iterator.remove();
             } else {
-                if (masterNode != null) { // TODO: can we remove this? Is resending shard failures the responsibility of shardStateAction?
-                    String message = "master " + masterNode + " has not removed previously failed shard. resending shard failure";
+                // TODO: can we remove this? Is resending shard failures the responsibility of shardStateAction?
+                if (clusterManagerNode != null) {
+                    String message = "cluster-manager "
+                        + clusterManagerNode
+                        + " has not removed previously failed shard. resending shard failure";
                     logger.trace("[{}] re-sending failed shard [{}], reason [{}]", matchedRouting.shardId(), matchedRouting, message);
                     shardStateAction.localShardFailed(matchedRouting, message, null, SHARD_STATE_ACTION_LISTENER, state);
                 }
@@ -401,7 +445,7 @@ private void removeIndices(final ClusterChangedEvent event) {
     }
 
     /**
-     * Notifies master about shards that don't exist but are supposed to be active on this node.
+     * Notifies cluster-manager about shards that don't exist but are supposed to be active on this node.
      *
      * @param state new cluster state
      */
@@ -415,7 +459,7 @@ private void failMissingShards(final ClusterState state) {
             if (shardRouting.initializing() == false
                 && failedShardsCache.containsKey(shardId) == false
                 && indicesService.getShardOrNull(shardId) == null) {
-                // the master thinks we are active, but we don't have this shard at all, mark it as failed
+                // the cluster-manager thinks we are active, but we don't have this shard at all, mark it as failed
                 sendFailShard(
                     shardRouting,
                     "master marked shard as active, but shard has not been created, mark shard as failed",
@@ -497,10 +541,22 @@ private void createIndices(final ClusterState state) {
 
             AllocatedIndex<? extends Shard> indexService = null;
             try {
-                indexService = indicesService.createIndex(indexMetadata, buildInIndexListener, true);
+                List<IndexEventListener> updatedIndexEventListeners = new ArrayList<>(builtInIndexListener);
+                if (entry.getValue().size() > 0
+                    && entry.getValue().get(0).recoverySource().getType() == Type.SNAPSHOT
+                    && indexMetadata.getSettings().getAsBoolean(SETTING_REMOTE_STORE_ENABLED, false)) {
+                    final IndexEventListener refreshListenerAfterSnapshotRestore = new IndexEventListener() {
+                        @Override
+                        public void afterIndexShardStarted(IndexShard indexShard) {
+                            indexShard.refresh("refresh to upload metadata to remote store");
+                        }
+                    };
+                    updatedIndexEventListeners.add(refreshListenerAfterSnapshotRestore);
+                }
+                indexService = indicesService.createIndex(indexMetadata, updatedIndexEventListeners, true);
                 if (indexService.updateMapping(null, indexMetadata) && sendRefreshMapping) {
                     nodeMappingRefreshAction.nodeMappingRefresh(
-                        state.nodes().getMasterNode(),
+                        state.nodes().getClusterManagerNode(),
                         new NodeMappingRefreshAction.NodeMappingRefreshRequest(
                             indexMetadata.getIndex().getName(),
                             indexMetadata.getIndexUUID(),
@@ -547,7 +603,7 @@ private void updateIndices(ClusterChangedEvent event) {
                     reason = "mapping update failed";
                     if (indexService.updateMapping(currentIndexMetadata, newIndexMetadata) && sendRefreshMapping) {
                         nodeMappingRefreshAction.nodeMappingRefresh(
-                            state.nodes().getMasterNode(),
+                            state.nodes().getClusterManagerNode(),
                             new NodeMappingRefreshAction.NodeMappingRefreshRequest(
                                 newIndexMetadata.getIndex().getName(),
                                 newIndexMetadata.getIndexUUID(),
@@ -614,14 +670,16 @@ private void createShard(DiscoveryNodes nodes, RoutingTable routingTable, ShardR
             logger.debug("{} creating shard with primary term [{}]", shardRouting.shardId(), primaryTerm);
             indicesService.createShard(
                 shardRouting,
+                checkpointPublisher,
                 recoveryTargetService,
-                new RecoveryListener(shardRouting, primaryTerm),
+                new RecoveryListener(shardRouting, primaryTerm, this),
                 repositoriesService,
                 failedShardHandler,
                 globalCheckpointSyncer,
                 retentionLeaseSyncer,
                 nodes.getLocalNode(),
-                sourceNode
+                sourceNode,
+                remoteStoreStatsTrackerFactory
             );
         } catch (Exception e) {
             failAndRemoveShard(shardRouting, true, "failed to create shard", e, state);
@@ -664,23 +722,23 @@ private void updateShard(
 
         final IndexShardState state = shard.state();
         if (shardRouting.initializing() && (state == IndexShardState.STARTED || state == IndexShardState.POST_RECOVERY)) {
-            // the master thinks we are initializing, but we are already started or on POST_RECOVERY and waiting
-            // for master to confirm a shard started message (either master failover, or a cluster event before
-            // we managed to tell the master we started), mark us as started
+            // the cluster-manager thinks we are initializing, but we are already started or on POST_RECOVERY and waiting
+            // for cluster-manager to confirm a shard started message (either cluster-manager failover, or a cluster event before
+            // we managed to tell the cluster-manager we started), mark us as started
             if (logger.isTraceEnabled()) {
                 logger.trace(
-                    "{} master marked shard as initializing, but shard has state [{}], resending shard started to {}",
+                    "{} cluster-manager marked shard as initializing, but shard has state [{}], resending shard started to {}",
                     shardRouting.shardId(),
                     state,
-                    nodes.getMasterNode()
+                    nodes.getClusterManagerNode()
                 );
             }
-            if (nodes.getMasterNode() != null) {
+            if (nodes.getClusterManagerNode() != null) {
                 shardStateAction.shardStarted(
                     shardRouting,
                     primaryTerm,
-                    "master "
-                        + nodes.getMasterNode()
+                    "cluster-manager "
+                        + nodes.getClusterManagerNode()
                         + " marked shard as initializing, but shard state is ["
                         + state
                         + "], mark shard as started",
@@ -730,39 +788,16 @@ private static DiscoveryNode findSourceNodeForPeerRecovery(
         return sourceNode;
     }
 
-    private class RecoveryListener implements PeerRecoveryTargetService.RecoveryListener {
-
-        /**
-         * ShardRouting with which the shard was created
-         */
-        private final ShardRouting shardRouting;
-
-        /**
-         * Primary term with which the shard was created
-         */
-        private final long primaryTerm;
-
-        private RecoveryListener(final ShardRouting shardRouting, final long primaryTerm) {
-            this.shardRouting = shardRouting;
-            this.primaryTerm = primaryTerm;
-        }
-
-        @Override
-        public void onRecoveryDone(final RecoveryState state) {
-            shardStateAction.shardStarted(shardRouting, primaryTerm, "after " + state.getRecoverySource(), SHARD_STATE_ACTION_LISTENER);
-        }
-
-        @Override
-        public void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure) {
-            handleRecoveryFailure(shardRouting, sendShardFailure, e);
-        }
-    }
-
     // package-private for testing
-    synchronized void handleRecoveryFailure(ShardRouting shardRouting, boolean sendShardFailure, Exception failure) {
+    public synchronized void handleRecoveryFailure(ShardRouting shardRouting, boolean sendShardFailure, Exception failure) {
         failAndRemoveShard(shardRouting, sendShardFailure, "failed recovery", failure, clusterService.state());
     }
 
+    public void handleRecoveryDone(ReplicationState state, ShardRouting shardRouting, long primaryTerm) {
+        RecoveryState recoveryState = (RecoveryState) state;
+        shardStateAction.shardStarted(shardRouting, primaryTerm, "after " + recoveryState.getRecoverySource(), SHARD_STATE_ACTION_LISTENER);
+    }
+
     private void failAndRemoveShard(
         ShardRouting shardRouting,
         boolean sendShardFailure,
@@ -837,6 +872,11 @@ public void accept(final IndexShard.ShardFailure shardFailure) {
         }
     }
 
+    /**
+     * A shard
+     *
+     * @opensearch.internal
+     */
     public interface Shard {
 
         /**
@@ -864,7 +904,7 @@ public interface Shard {
          * - Updates and persists the new routing value.
          * - Updates the primary term if this shard is a primary.
          * - Updates the allocation ids that are tracked by the shard if it is a primary.
-         *   See {@link ReplicationTracker#updateFromMaster(long, Set, IndexShardRoutingTable)} for details.
+         *   See {@link ReplicationTracker#updateFromClusterManager(long, Set, IndexShardRoutingTable)} for details.
          *
          * @param shardRouting                the new routing entry
          * @param primaryTerm                 the new primary term
@@ -885,6 +925,11 @@ void updateShardState(
         ) throws IOException;
     }
 
+    /**
+     * An allocated index
+     *
+     * @opensearch.internal
+     */
     public interface AllocatedIndex<T extends Shard> extends Iterable<T>, IndexComponent {
 
         /**
@@ -917,6 +962,11 @@ public interface AllocatedIndex<T extends Shard> extends Iterable<T>, IndexCompo
         void removeShard(int shardId, String message);
     }
 
+    /**
+     * Allocated indices
+     *
+     * @opensearch.internal
+     */
     public interface AllocatedIndices<T extends Shard, U extends AllocatedIndex<T>> extends Iterable<U> {
 
         /**
@@ -974,19 +1024,22 @@ U createIndex(IndexMetadata indexMetadata, List<IndexEventListener> builtInIndex
          * @param retentionLeaseSyncer   a callback when this shard syncs retention leases
          * @param targetNode             the node where this shard will be recovered
          * @param sourceNode             the source node to recover this shard from (it might be null)
+         * @param remoteStoreStatsTrackerFactory factory for remote store stats trackers
          * @return a new shard
          * @throws IOException if an I/O exception occurs when creating the shard
          */
         T createShard(
             ShardRouting shardRouting,
+            SegmentReplicationCheckpointPublisher checkpointPublisher,
             PeerRecoveryTargetService recoveryTargetService,
-            PeerRecoveryTargetService.RecoveryListener recoveryListener,
+            RecoveryListener recoveryListener,
             RepositoriesService repositoriesService,
             Consumer<IndexShard.ShardFailure> onShardFailure,
             Consumer<ShardId> globalCheckpointSyncer,
             RetentionLeaseSyncer retentionLeaseSyncer,
             DiscoveryNode targetNode,
-            @Nullable DiscoveryNode sourceNode
+            @Nullable DiscoveryNode sourceNode,
+            RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
         ) throws IOException;
 
         /**
@@ -1003,6 +1056,11 @@ default T getShardOrNull(ShardId shardId) {
         void processPendingDeletes(Index index, IndexSettings indexSettings, TimeValue timeValue) throws IOException, InterruptedException,
             ShardLockObtainFailedException;
 
+        /**
+         * Why the index was removed
+         *
+         * @opensearch.internal
+         */
         enum IndexRemovalReason {
             /**
              * Shard of this index were previously assigned to this node but all shards have been relocated.
diff --git a/server/src/main/java/org/opensearch/indices/cluster/package-info.java b/server/src/main/java/org/opensearch/indices/cluster/package-info.java
new file mode 100644
index 0000000000000..9d42103a9af41
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/cluster/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Indices ClusterState Service package. */
+package org.opensearch.indices.cluster;
diff --git a/server/src/main/java/org/opensearch/indices/fielddata/cache/IndicesFieldDataCache.java b/server/src/main/java/org/opensearch/indices/fielddata/cache/IndicesFieldDataCache.java
index a632175e0a609..e2fac15f44604 100644
--- a/server/src/main/java/org/opensearch/indices/fielddata/cache/IndicesFieldDataCache.java
+++ b/server/src/main/java/org/opensearch/indices/fielddata/cache/IndicesFieldDataCache.java
@@ -32,38 +32,43 @@
 
 package org.opensearch.indices.fielddata.cache;
 
-import java.util.Collections;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.IndexReader.CacheKey;
+import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.util.Accountable;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.cache.Cache;
 import org.opensearch.common.cache.CacheBuilder;
 import org.opensearch.common.cache.RemovalListener;
 import org.opensearch.common.cache.RemovalNotification;
+import org.opensearch.common.cache.RemovalReason;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.index.Index;
-import org.opensearch.index.fielddata.LeafFieldData;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.shard.ShardUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.function.ToLongBiFunction;
 
+/**
+ * The field data cache for multiple indices
+ *
+ * @opensearch.internal
+ */
 public class IndicesFieldDataCache implements RemovalListener<IndicesFieldDataCache.Key, Accountable>, Releasable {
 
     private static final Logger logger = LogManager.getLogger(IndicesFieldDataCache.class);
@@ -110,7 +115,7 @@ public void onRemoval(RemovalNotification<Key, Accountable> notification) {
                 listener.onRemoval(
                     key.shardId,
                     indexCache.fieldName,
-                    notification.getRemovalReason() == RemovalNotification.RemovalReason.EVICTED,
+                    notification.getRemovalReason() == RemovalReason.EVICTED,
                     value.ramBytesUsed()
                 );
             } catch (Exception e) {
@@ -120,6 +125,11 @@ public void onRemoval(RemovalNotification<Key, Accountable> notification) {
         }
     }
 
+    /**
+     * Computes a weight based on ramBytesUsed
+     *
+     * @opensearch.internal
+     */
     public static class FieldDataWeigher implements ToLongBiFunction<Key, Accountable> {
         @Override
         public long applyAsLong(Key key, Accountable ramUsage) {
@@ -130,6 +140,8 @@ public long applyAsLong(Key key, Accountable ramUsage) {
 
     /**
      * A specific cache instance for the relevant parameters of it (index, fieldNames, fieldType).
+     *
+     * @opensearch.internal
      */
     static class IndexFieldCache implements IndexFieldDataCache, IndexReader.ClosedListener {
         private final Logger logger;
@@ -237,6 +249,11 @@ public void clear(String fieldName) {
         }
     }
 
+    /**
+     * Key for the indices field data cache
+     *
+     * @opensearch.internal
+     */
     public static class Key {
         public final IndexFieldCache indexCache;
         public final IndexReader.CacheKey readerKey;
diff --git a/server/src/main/java/org/opensearch/indices/fielddata/cache/package-info.java b/server/src/main/java/org/opensearch/indices/fielddata/cache/package-info.java
new file mode 100644
index 0000000000000..fc52c884edeb7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/fielddata/cache/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** FieldData Cache package. */
+package org.opensearch.indices.fielddata.cache;
diff --git a/server/src/main/java/org/opensearch/indices/fielddata/package-info.java b/server/src/main/java/org/opensearch/indices/fielddata/package-info.java
new file mode 100644
index 0000000000000..465badca28de7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/fielddata/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Indices FieldData package. */
+package org.opensearch.indices.fielddata;
diff --git a/server/src/main/java/org/opensearch/indices/mapper/MapperRegistry.java b/server/src/main/java/org/opensearch/indices/mapper/MapperRegistry.java
index d37f82c7a484f..3a1d7b1ebb1e3 100644
--- a/server/src/main/java/org/opensearch/indices/mapper/MapperRegistry.java
+++ b/server/src/main/java/org/opensearch/indices/mapper/MapperRegistry.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.indices.mapper;
 
-import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.index.mapper.AllFieldMapper;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MetadataFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.plugins.MapperPlugin;
 
 import java.util.Collections;
@@ -47,12 +46,14 @@
 
 /**
  * A registry for all field mappers.
+ *
+ * @opensearch.internal
  */
 public final class MapperRegistry {
 
     private final Map<String, Mapper.TypeParser> mapperParsers;
     private final Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsers;
-    private final Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsers6x;
+    private final Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsersPre20;
     private final Function<String, Predicate<String>> fieldFilter;
 
     public MapperRegistry(
@@ -62,11 +63,9 @@ public MapperRegistry(
     ) {
         this.mapperParsers = Collections.unmodifiableMap(new LinkedHashMap<>(mapperParsers));
         this.metadataMapperParsers = Collections.unmodifiableMap(new LinkedHashMap<>(metadataMapperParsers));
-        // add the _all field mapper for indices created in 6x
-        Map<String, MetadataFieldMapper.TypeParser> metadata6x = new LinkedHashMap<>();
-        metadata6x.put(AllFieldMapper.NAME, AllFieldMapper.PARSER);
-        metadata6x.putAll(metadataMapperParsers);
-        this.metadataMapperParsers6x = Collections.unmodifiableMap(metadata6x);
+        Map<String, MetadataFieldMapper.TypeParser> tempPre20 = new LinkedHashMap<>(metadataMapperParsers);
+        tempPre20.remove(NestedPathFieldMapper.NAME);
+        this.metadataMapperParsersPre20 = Collections.unmodifiableMap(tempPre20);
         this.fieldFilter = fieldFilter;
     }
 
@@ -83,7 +82,7 @@ public Map<String, Mapper.TypeParser> getMapperParsers() {
      * returned map uses the name of the field as a key.
      */
     public Map<String, MetadataFieldMapper.TypeParser> getMetadataMapperParsers(Version indexCreatedVersion) {
-        return indexCreatedVersion.onOrAfter(LegacyESVersion.V_7_0_0) ? metadataMapperParsers : metadataMapperParsers6x;
+        return indexCreatedVersion.onOrAfter(Version.V_2_0_0) ? metadataMapperParsers : metadataMapperParsersPre20;
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/indices/mapper/package-info.java b/server/src/main/java/org/opensearch/indices/mapper/package-info.java
new file mode 100644
index 0000000000000..85c2927ae4c03
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/mapper/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Field Mapper Registry package. */
+package org.opensearch.indices.mapper;
diff --git a/server/src/main/java/org/opensearch/indices/package-info.java b/server/src/main/java/org/opensearch/indices/package-info.java
new file mode 100644
index 0000000000000..0f2ea1e1a9848
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Indices Module package. */
+package org.opensearch.indices;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/DelayRecoveryException.java b/server/src/main/java/org/opensearch/indices/recovery/DelayRecoveryException.java
index 994634cb43413..687bed05f0bef 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/DelayRecoveryException.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/DelayRecoveryException.java
@@ -33,14 +33,14 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * An exception marking that this recovery attempt should be ignored (since probably, we already recovered).
  *
- *
+ * @opensearch.internal
  */
 public class DelayRecoveryException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/FileChunkRequest.java b/server/src/main/java/org/opensearch/indices/recovery/FileChunkRequest.java
new file mode 100644
index 0000000000000..cc95d18604cff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/FileChunkRequest.java
@@ -0,0 +1,163 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.apache.lucene.util.Version;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.StoreFileMetadata;
+
+import java.io.IOException;
+
+/**
+ * Request containing a file chunk.
+ *
+ * @opensearch.internal
+ */
+public final class FileChunkRequest extends RecoveryTransportRequest {
+    private final boolean lastChunk;
+    private final long recoveryId;
+    private final ShardId shardId;
+    private final long position;
+    private final BytesReference content;
+    private final StoreFileMetadata metadata;
+    private final long sourceThrottleTimeInNanos;
+
+    private final int totalTranslogOps;
+
+    public FileChunkRequest(StreamInput in) throws IOException {
+        super(in);
+        recoveryId = in.readLong();
+        shardId = new ShardId(in);
+        String name = in.readString();
+        position = in.readVLong();
+        long length = in.readVLong();
+        String checksum = in.readString();
+        content = in.readBytesReference();
+        Version writtenBy = Lucene.parseVersionLenient(in.readString(), null);
+        assert writtenBy != null;
+        metadata = new StoreFileMetadata(name, length, checksum, writtenBy);
+        lastChunk = in.readBoolean();
+        totalTranslogOps = in.readVInt();
+        sourceThrottleTimeInNanos = in.readLong();
+    }
+
+    public FileChunkRequest(
+        long recoveryId,
+        final long requestSeqNo,
+        ShardId shardId,
+        StoreFileMetadata metadata,
+        long position,
+        BytesReference content,
+        boolean lastChunk,
+        int totalTranslogOps,
+        long sourceThrottleTimeInNanos
+    ) {
+        super(requestSeqNo);
+        this.recoveryId = recoveryId;
+        this.shardId = shardId;
+        this.metadata = metadata;
+        this.position = position;
+        this.content = content;
+        this.lastChunk = lastChunk;
+        this.totalTranslogOps = totalTranslogOps;
+        this.sourceThrottleTimeInNanos = sourceThrottleTimeInNanos;
+    }
+
+    public long recoveryId() {
+        return this.recoveryId;
+    }
+
+    public ShardId shardId() {
+        return shardId;
+    }
+
+    public String name() {
+        return metadata.name();
+    }
+
+    public long position() {
+        return position;
+    }
+
+    public long length() {
+        return metadata.length();
+    }
+
+    public BytesReference content() {
+        return content;
+    }
+
+    public int totalTranslogOps() {
+        return totalTranslogOps;
+    }
+
+    public long sourceThrottleTimeInNanos() {
+        return sourceThrottleTimeInNanos;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeLong(recoveryId);
+        shardId.writeTo(out);
+        out.writeString(metadata.name());
+        out.writeVLong(position);
+        out.writeVLong(metadata.length());
+        out.writeString(metadata.checksum());
+        out.writeBytesReference(content);
+        out.writeString(metadata.writtenBy().toString());
+        out.writeBoolean(lastChunk);
+        out.writeVInt(totalTranslogOps);
+        out.writeLong(sourceThrottleTimeInNanos);
+    }
+
+    @Override
+    public String toString() {
+        return shardId + ": name='" + name() + '\'' + ", position=" + position + ", length=" + length();
+    }
+
+    public StoreFileMetadata metadata() {
+        return metadata;
+    }
+
+    /**
+     * Returns <code>true</code> if this chunk is the last chunk in the stream.
+     */
+    public boolean lastChunk() {
+        return lastChunk;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/FileChunkWriter.java b/server/src/main/java/org/opensearch/indices/recovery/FileChunkWriter.java
new file mode 100644
index 0000000000000..a1ae6af8e15e9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/FileChunkWriter.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.store.StoreFileMetadata;
+
+/**
+ * Writes a partial file chunk to the target store.
+ *
+ * @opensearch.internal
+ */
+@FunctionalInterface
+public interface FileChunkWriter {
+
+    void writeFileChunk(
+        StoreFileMetadata fileMetadata,
+        long position,
+        BytesReference content,
+        boolean lastChunk,
+        int totalTranslogOps,
+        ActionListener<Void> listener
+    );
+
+    default void cancel() {}
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/ForceSyncRequest.java b/server/src/main/java/org/opensearch/indices/recovery/ForceSyncRequest.java
new file mode 100644
index 0000000000000..09b13b2e5451d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/ForceSyncRequest.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+
+import java.io.IOException;
+
+/**
+ * Request to force a round of segment replication on primary target
+ *
+ * @opensearch.internal
+ */
+public class ForceSyncRequest extends RecoveryTransportRequest {
+    private final long recoveryId;
+    private final ShardId shardId;
+
+    public ForceSyncRequest(long requestSeqNo, long recoveryId, ShardId shardId) {
+        super(requestSeqNo);
+        this.recoveryId = recoveryId;
+        this.shardId = shardId;
+    }
+
+    public ForceSyncRequest(StreamInput in) throws IOException {
+        super(in);
+        this.recoveryId = in.readLong();
+        this.shardId = new ShardId(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeLong(recoveryId);
+        shardId.writeTo(out);
+    }
+
+    public long getRecoveryId() {
+        return recoveryId;
+    }
+
+    public ShardId getShardId() {
+        return shardId;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java b/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java
new file mode 100644
index 0000000000000..ac6b2e6b77d18
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java
@@ -0,0 +1,233 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.apache.lucene.index.IndexCommit;
+import org.opensearch.action.StepListener;
+import org.opensearch.action.support.ThreadedActionListener;
+import org.opensearch.action.support.replication.ReplicationResponse;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.engine.RecoveryEngineException;
+import org.opensearch.index.seqno.ReplicationTracker;
+import org.opensearch.index.seqno.RetentionLease;
+import org.opensearch.index.seqno.RetentionLeaseNotFoundException;
+import org.opensearch.index.seqno.RetentionLeases;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.RunUnderPrimaryPermit;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transports;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.function.Consumer;
+
+/**
+ * This handler is used for node-to-node peer recovery when the recovery target is a replica/ or a relocating primary
+ * shard with translog backed by local store.
+ *
+ * @opensearch.internal
+ */
+public class LocalStorePeerRecoverySourceHandler extends RecoverySourceHandler {
+
+    public LocalStorePeerRecoverySourceHandler(
+        IndexShard shard,
+        RecoveryTargetHandler recoveryTarget,
+        ThreadPool threadPool,
+        StartRecoveryRequest request,
+        int fileChunkSizeInBytes,
+        int maxConcurrentFileChunks,
+        int maxConcurrentOperations
+    ) {
+        super(shard, recoveryTarget, threadPool, request, fileChunkSizeInBytes, maxConcurrentFileChunks, maxConcurrentOperations);
+    }
+
+    @Override
+    protected void innerRecoveryToTarget(ActionListener<RecoveryResponse> listener, Consumer<Exception> onFailure) throws IOException {
+        final SetOnce<RetentionLease> retentionLeaseRef = new SetOnce<>();
+
+        RunUnderPrimaryPermit.run(() -> {
+            final IndexShardRoutingTable routingTable = shard.getReplicationGroup().getRoutingTable();
+            ShardRouting targetShardRouting = routingTable.getByAllocationId(request.targetAllocationId());
+            if (targetShardRouting == null) {
+                logger.debug(
+                    "delaying recovery of {} as it is not listed as assigned to target node {}",
+                    request.shardId(),
+                    request.targetNode()
+                );
+                throw new DelayRecoveryException("source node does not have the shard listed in its state as allocated on the node");
+            }
+            assert targetShardRouting.initializing() : "expected recovery target to be initializing but was " + targetShardRouting;
+            retentionLeaseRef.set(shard.getRetentionLeases().get(ReplicationTracker.getPeerRecoveryRetentionLeaseId(targetShardRouting)));
+        }, shardId + " validating recovery target [" + request.targetAllocationId() + "] registered ", shard, cancellableThreads, logger);
+        final Closeable retentionLock = shard.acquireHistoryRetentionLock();
+        resources.add(retentionLock);
+        final long startingSeqNo;
+        final boolean isSequenceNumberBasedRecovery = request.startingSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO
+            && isTargetSameHistory()
+            && shard.hasCompleteHistoryOperations(PEER_RECOVERY_NAME, request.startingSeqNo())
+            && ((retentionLeaseRef.get() == null && shard.useRetentionLeasesInPeerRecovery() == false)
+                || (retentionLeaseRef.get() != null && retentionLeaseRef.get().retainingSequenceNumber() <= request.startingSeqNo()));
+        // NB check hasCompleteHistoryOperations when computing isSequenceNumberBasedRecovery, even if there is a retention lease,
+        // because when doing a rolling upgrade from earlier than 7.4 we may create some leases that are initially unsatisfied. It's
+        // possible there are other cases where we cannot satisfy all leases, because that's not a property we currently expect to hold.
+        // Also it's pretty cheap when soft deletes are enabled, and it'd be a disaster if we tried a sequence-number-based recovery
+        // without having a complete history.
+
+        if (isSequenceNumberBasedRecovery && retentionLeaseRef.get() != null) {
+            // all the history we need is retained by an existing retention lease, so we do not need a separate retention lock
+            retentionLock.close();
+            logger.trace("history is retained by {}", retentionLeaseRef.get());
+        } else {
+            // all the history we need is retained by the retention lock, obtained before calling shard.hasCompleteHistoryOperations()
+            // and before acquiring the safe commit we'll be using, so we can be certain that all operations after the safe commit's
+            // local checkpoint will be retained for the duration of this recovery.
+            logger.trace("history is retained by retention lock");
+        }
+
+        final StepListener<SendFileResult> sendFileStep = new StepListener<>();
+        final StepListener<TimeValue> prepareEngineStep = new StepListener<>();
+        final StepListener<SendSnapshotResult> sendSnapshotStep = new StepListener<>();
+
+        if (isSequenceNumberBasedRecovery) {
+            logger.trace("performing sequence numbers based recovery. starting at [{}]", request.startingSeqNo());
+            startingSeqNo = request.startingSeqNo();
+            if (retentionLeaseRef.get() == null) {
+                createRetentionLease(startingSeqNo, ActionListener.map(sendFileStep, ignored -> SendFileResult.EMPTY));
+            } else {
+                sendFileStep.onResponse(SendFileResult.EMPTY);
+            }
+        } else {
+            final GatedCloseable<IndexCommit> wrappedSafeCommit;
+            try {
+                wrappedSafeCommit = acquireSafeCommit(shard);
+                resources.add(wrappedSafeCommit);
+            } catch (final Exception e) {
+                throw new RecoveryEngineException(shard.shardId(), 1, "snapshot failed", e);
+            }
+
+            // Try and copy enough operations to the recovering peer so that if it is promoted to primary then it has a chance of being
+            // able to recover other replicas using operations-based recoveries. If we are not using retention leases then we
+            // conservatively copy all available operations. If we are using retention leases then "enough operations" is just the
+            // operations from the local checkpoint of the safe commit onwards, because when using soft deletes the safe commit retains
+            // at least as much history as anything else. The safe commit will often contain all the history retained by the current set
+            // of retention leases, but this is not guaranteed: an earlier peer recovery from a different primary might have created a
+            // retention lease for some history that this primary already discarded, since we discard history when the global checkpoint
+            // advances and not when creating a new safe commit. In any case this is a best-effort thing since future recoveries can
+            // always fall back to file-based ones, and only really presents a problem if this primary fails before things have settled
+            // down.
+            startingSeqNo = Long.parseLong(wrappedSafeCommit.get().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)) + 1L;
+            logger.trace("performing file-based recovery followed by history replay starting at [{}]", startingSeqNo);
+
+            try {
+                final int estimateNumOps = countNumberOfHistoryOperations(startingSeqNo);
+                final Releasable releaseStore = acquireStore(shard.store());
+                resources.add(releaseStore);
+                onSendFileStepComplete(sendFileStep, wrappedSafeCommit, releaseStore);
+
+                final StepListener<ReplicationResponse> deleteRetentionLeaseStep = new StepListener<>();
+                RunUnderPrimaryPermit.run(() -> {
+                    try {
+                        // If the target previously had a copy of this shard then a file-based recovery might move its global
+                        // checkpoint backwards. We must therefore remove any existing retention lease so that we can create a
+                        // new one later on in the recovery.
+                        shard.removePeerRecoveryRetentionLease(
+                            request.targetNode().getId(),
+                            new ThreadedActionListener<>(
+                                logger,
+                                shard.getThreadPool(),
+                                ThreadPool.Names.GENERIC,
+                                deleteRetentionLeaseStep,
+                                false
+                            )
+                        );
+                    } catch (RetentionLeaseNotFoundException e) {
+                        logger.debug("no peer-recovery retention lease for " + request.targetAllocationId());
+                        deleteRetentionLeaseStep.onResponse(null);
+                    }
+                }, shardId + " removing retention lease for [" + request.targetAllocationId() + "]", shard, cancellableThreads, logger);
+
+                deleteRetentionLeaseStep.whenComplete(ignored -> {
+                    logger.debug("deleteRetentionLeaseStep completed");
+                    assert Transports.assertNotTransportThread(this + "[phase1]");
+                    phase1(wrappedSafeCommit.get(), startingSeqNo, () -> estimateNumOps, sendFileStep, false);
+                }, onFailure);
+
+            } catch (final Exception e) {
+                throw new RecoveryEngineException(shard.shardId(), 1, "sendFileStep failed", e);
+            }
+        }
+        assert startingSeqNo >= 0 : "startingSeqNo must be non negative. got: " + startingSeqNo;
+
+        sendFileStep.whenComplete(r -> {
+            logger.debug("sendFileStep completed");
+            assert Transports.assertNotTransportThread(this + "[prepareTargetForTranslog]");
+            // For a sequence based recovery, the target can keep its local translog
+            prepareTargetForTranslog(countNumberOfHistoryOperations(startingSeqNo), prepareEngineStep);
+        }, onFailure);
+
+        prepareEngineStep.whenComplete(prepareEngineTime -> {
+            logger.debug("prepareEngineStep completed");
+            assert Transports.assertNotTransportThread(this + "[phase2]");
+            /*
+             * add shard to replication group (shard will receive replication requests from this point on) now that engine is open.
+             * This means that any document indexed into the primary after this will be replicated to this replica as well
+             * make sure to do this before sampling the max sequence number in the next step, to ensure that we send
+             * all documents up to maxSeqNo in phase2.
+             */
+            RunUnderPrimaryPermit.run(
+                () -> shard.initiateTracking(request.targetAllocationId()),
+                shardId + " initiating tracking of " + request.targetAllocationId(),
+                shard,
+                cancellableThreads,
+                logger
+            );
+
+            final long endingSeqNo = shard.seqNoStats().getMaxSeqNo();
+            if (logger.isTraceEnabled()) {
+                logger.trace("snapshot translog for recovery; current size is [{}]", countNumberOfHistoryOperations(startingSeqNo));
+            }
+            final Translog.Snapshot phase2Snapshot = shard.newChangesSnapshot(
+                PEER_RECOVERY_NAME,
+                startingSeqNo,
+                Long.MAX_VALUE,
+                false,
+                true
+            );
+            resources.add(phase2Snapshot);
+            retentionLock.close();
+
+            // we have to capture the max_seen_auto_id_timestamp and the max_seq_no_of_updates to make sure that these values
+            // are at least as high as the corresponding values on the primary when any of these operations were executed on it.
+            final long maxSeenAutoIdTimestamp = shard.getMaxSeenAutoIdTimestamp();
+            final long maxSeqNoOfUpdatesOrDeletes = shard.getMaxSeqNoOfUpdatesOrDeletes();
+            final RetentionLeases retentionLeases = shard.getRetentionLeases();
+            final long mappingVersionOnPrimary = shard.indexSettings().getIndexMetadata().getMappingVersion();
+            phase2(
+                startingSeqNo,
+                endingSeqNo,
+                phase2Snapshot,
+                maxSeenAutoIdTimestamp,
+                maxSeqNoOfUpdatesOrDeletes,
+                retentionLeases,
+                mappingVersionOnPrimary,
+                sendSnapshotStep
+            );
+
+        }, onFailure);
+        finalizeStepAndCompleteFuture(startingSeqNo, sendSnapshotStep, sendFileStep, prepareEngineStep, onFailure);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/MultiChunkTransfer.java b/server/src/main/java/org/opensearch/indices/recovery/MultiChunkTransfer.java
index 78983c9ab5cf8..e277160637366 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/MultiChunkTransfer.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/MultiChunkTransfer.java
@@ -34,12 +34,12 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.Assertions;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.util.concurrent.AsyncIOProcessor;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.seqno.LocalCheckpointTracker;
 
 import java.io.Closeable;
@@ -68,6 +68,8 @@
  * greater than {@code maxConcurrentFileChunks}), the sending/requesting thread will abort its execution. That process will be resumed by
  * one of the networking threads which receive/handle the responses of the current pending file chunk requests. This process will continue
  * until all chunk requests are sent/responded.
+ *
+ * @opensearch.internal
  */
 public abstract class MultiChunkTransfer<Source, Request extends MultiChunkTransfer.ChunkRequest> implements Closeable {
     private Status status = Status.PROCESSING;
@@ -209,6 +211,11 @@ protected void onNewResource(Source resource) throws IOException {
 
     protected abstract void handleError(Source resource, Exception e) throws Exception;
 
+    /**
+     * A file chunk item as the response
+     *
+     * @opensearch.internal
+     */
     private static class FileChunkResponseItem<Source> {
         final long requestSeqId;
         final Source source;
@@ -221,6 +228,11 @@ private static class FileChunkResponseItem<Source> {
         }
     }
 
+    /**
+     * A chunk request
+     *
+     * @opensearch.internal
+     */
     public interface ChunkRequest {
         /**
          * @return {@code true} if this chunk request is the last chunk of the current file
diff --git a/server/src/main/java/org/opensearch/indices/recovery/MultiFileWriter.java b/server/src/main/java/org/opensearch/indices/recovery/MultiFileWriter.java
index f0295fdd2fbef..29ee097d36cac 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/MultiFileWriter.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/MultiFileWriter.java
@@ -37,13 +37,14 @@
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.concurrent.AbstractRefCounted;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.transport.Transports;
 
 import java.io.IOException;
@@ -56,9 +57,14 @@
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+/**
+ * A multi file writer utility for recovery
+ *
+ * @opensearch.internal
+ */
 public class MultiFileWriter extends AbstractRefCounted implements Releasable {
 
-    public MultiFileWriter(Store store, RecoveryState.Index indexState, String tempFilePrefix, Logger logger, Runnable ensureOpen) {
+    public MultiFileWriter(Store store, ReplicationLuceneIndex indexState, String tempFilePrefix, Logger logger, Runnable ensureOpen) {
         super("multi_file_writer");
         this.store = store;
         this.indexState = indexState;
@@ -71,7 +77,7 @@ public MultiFileWriter(Store store, RecoveryState.Index indexState, String tempF
     private final AtomicBoolean closed = new AtomicBoolean(false);
     private final Logger logger;
     private final Store store;
-    private final RecoveryState.Index indexState;
+    private final ReplicationLuceneIndex indexState;
     private final String tempFilePrefix;
 
     private final ConcurrentMap<String, IndexOutput> openIndexOutputs = ConcurrentCollections.newConcurrentMap();
@@ -91,6 +97,10 @@ String getTempNameForFile(String origFile) {
         return tempFilePrefix + origFile;
     }
 
+    public Map<String, String> getTempFileNames() {
+        return tempFileNames;
+    }
+
     public IndexOutput getOpenIndexOutput(String key) {
         ensureOpen.run();
         return openIndexOutputs.get(key);
@@ -150,7 +160,10 @@ private void innerWriteFileChunk(StoreFileMetadata fileMetadata, long position,
                 + temporaryFileName
                 + "] in "
                 + Arrays.toString(store.directory().listAll());
-            store.directory().sync(Collections.singleton(temporaryFileName));
+            // With Segment Replication, we will fsync after a full commit has been received.
+            if (store.indexSettings().isSegRepEnabled() == false) {
+                store.directory().sync(Collections.singleton(temporaryFileName));
+            }
             IndexOutput remove = removeOpenIndexOutputs(name);
             assert remove == null || remove == indexOutput; // remove maybe null if we got finished
         }
@@ -193,6 +206,11 @@ public void renameAllTempFiles() throws IOException {
         store.renameTempFilesSafe(tempFileNames);
     }
 
+    /**
+     * A file chunk
+     *
+     * @opensearch.internal
+     */
     static final class FileChunk {
         final StoreFileMetadata md;
         final BytesReference content;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryNotFound.java b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryNotFound.java
index 30a0f8053b109..ed6246ec73fed 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryNotFound.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryNotFound.java
@@ -33,11 +33,16 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if peer recovery is not found
+ *
+ * @opensearch.internal
+ */
 public class PeerRecoveryNotFound extends ResourceNotFoundException {
 
     public PeerRecoveryNotFound(final long recoveryId, final ShardId shardId, final String targetAllocationId) {
diff --git a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoverySourceService.java b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoverySourceService.java
index 5e9db2e1d67f3..6c7632a8a408d 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoverySourceService.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoverySourceService.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ChannelActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterChangedEvent;
@@ -46,14 +45,15 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.inject.Inject;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -72,11 +72,18 @@
 /**
  * The source recovery accepts recovery requests from other peer shards and start the recovery process from this
  * source shard to the target shard.
+ *
+ * @opensearch.internal
  */
 public class PeerRecoverySourceService extends AbstractLifecycleComponent implements IndexEventListener, ClusterStateListener {
 
     private static final Logger logger = LogManager.getLogger(PeerRecoverySourceService.class);
 
+    /**
+     * The internal actions
+     *
+     * @opensearch.internal
+     */
     public static class Actions {
         public static final String START_RECOVERY = "internal:index/shard/recovery/start_recovery";
         public static final String REESTABLISH_RECOVERY = "internal:index/shard/recovery/reestablish_recovery";
@@ -371,15 +378,7 @@ private Tuple<RecoverySourceHandler, RemoteRecoveryTargetHandler> createRecovery
                     recoverySettings,
                     throttleTime -> shard.recoveryStats().addThrottleTime(throttleTime)
                 );
-                handler = new RecoverySourceHandler(
-                    shard,
-                    recoveryTarget,
-                    shard.getThreadPool(),
-                    request,
-                    Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
-                    recoverySettings.getMaxConcurrentFileChunks(),
-                    recoverySettings.getMaxConcurrentOperations()
-                );
+                handler = RecoverySourceHandlerFactory.create(shard, recoveryTarget, request, recoverySettings);
                 return Tuple.tuple(handler, recoveryTarget);
             }
         }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryTargetService.java b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryTargetService.java
index d7c3421b1de93..e59766d0274f1 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryTargetService.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/PeerRecoveryTargetService.java
@@ -36,40 +36,39 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.store.RateLimiter;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
-import org.opensearch.action.support.ChannelActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.engine.RecoveryEngineException;
 import org.opensearch.index.mapper.MapperException;
-import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IllegalIndexShardStateException;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogCorruptedException;
-import org.opensearch.indices.recovery.RecoveriesCollection.RecoveryRef;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationCollection.ReplicationRef;
+import org.opensearch.indices.replication.common.ReplicationTimer;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ConnectTransportException;
@@ -77,7 +76,6 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -93,11 +91,18 @@
  * <p>
  * Note, it can be safely assumed that there will only be a single recovery per shard (index+id) and
  * not several of them (since we don't allocate several shard replicas to the same node).
+ *
+ * @opensearch.internal
  */
 public class PeerRecoveryTargetService implements IndexEventListener {
 
     private static final Logger logger = LogManager.getLogger(PeerRecoveryTargetService.class);
 
+    /**
+     * The internal actions
+     *
+     * @opensearch.internal
+     */
     public static class Actions {
         public static final String FILES_INFO = "internal:index/shard/recovery/filesInfo";
         public static final String FILE_CHUNK = "internal:index/shard/recovery/file_chunk";
@@ -115,7 +120,7 @@ public static class Actions {
     private final RecoverySettings recoverySettings;
     private final ClusterService clusterService;
 
-    private final RecoveriesCollection onGoingRecoveries;
+    private final ReplicationCollection<RecoveryTarget> onGoingRecoveries;
 
     public PeerRecoveryTargetService(
         ThreadPool threadPool,
@@ -127,7 +132,7 @@ public PeerRecoveryTargetService(
         this.transportService = transportService;
         this.recoverySettings = recoverySettings;
         this.clusterService = clusterService;
-        this.onGoingRecoveries = new RecoveriesCollection(logger, threadPool);
+        this.onGoingRecoveries = new ReplicationCollection<>(logger, threadPool);
 
         transportService.registerRequestHandler(
             Actions.FILES_INFO,
@@ -138,7 +143,7 @@ public PeerRecoveryTargetService(
         transportService.registerRequestHandler(
             Actions.FILE_CHUNK,
             ThreadPool.Names.GENERIC,
-            RecoveryFileChunkRequest::new,
+            FileChunkRequest::new,
             new FileChunkTransportRequestHandler()
         );
         transportService.registerRequestHandler(
@@ -176,13 +181,16 @@ public PeerRecoveryTargetService(
     @Override
     public void beforeIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {
         if (indexShard != null) {
-            onGoingRecoveries.cancelRecoveriesForShard(shardId, "shard closed");
+            onGoingRecoveries.cancelForShard(shardId, "shard closed");
         }
     }
 
     public void startRecovery(final IndexShard indexShard, final DiscoveryNode sourceNode, final RecoveryListener listener) {
         // create a new recovery status, and process...
-        final long recoveryId = onGoingRecoveries.startRecovery(indexShard, sourceNode, listener, recoverySettings.activityTimeout());
+        final long recoveryId = onGoingRecoveries.start(
+            new RecoveryTarget(indexShard, sourceNode, listener),
+            recoverySettings.activityTimeout()
+        );
         // we fork off quickly here and go async but this is called from the cluster state applier thread too and that can cause
         // assertions to trip if we executed it on the same thread hence we fork off to the generic threadpool.
         threadPool.generic().execute(new RecoveryRunner(recoveryId));
@@ -199,9 +207,9 @@ protected void retryRecovery(final long recoveryId, final String reason, TimeVal
     }
 
     private void retryRecovery(final long recoveryId, final TimeValue retryAfter, final TimeValue activityTimeout) {
-        RecoveryTarget newTarget = onGoingRecoveries.resetRecovery(recoveryId, activityTimeout);
+        RecoveryTarget newTarget = onGoingRecoveries.reset(recoveryId, activityTimeout);
         if (newTarget != null) {
-            threadPool.scheduleUnlessShuttingDown(retryAfter, ThreadPool.Names.GENERIC, new RecoveryRunner(newTarget.recoveryId()));
+            threadPool.scheduleUnlessShuttingDown(retryAfter, ThreadPool.Names.GENERIC, new RecoveryRunner(newTarget.getId()));
         }
     }
 
@@ -211,12 +219,18 @@ protected void reestablishRecovery(final StartRecoveryRequest request, final Str
         threadPool.scheduleUnlessShuttingDown(retryAfter, ThreadPool.Names.GENERIC, new RecoveryRunner(recoveryId, request));
     }
 
+    /**
+     * Initiates recovery of the replica. TODO - Need to revisit it with PRRL and later. @see
+     * <a href="https://github.com/opensearch-project/OpenSearch/issues/4502">github issue</a> on it.
+     * @param recoveryId recovery id
+     * @param preExistingRequest start recovery request
+     */
     private void doRecovery(final long recoveryId, final StartRecoveryRequest preExistingRequest) {
         final String actionName;
         final TransportRequest requestToSend;
         final StartRecoveryRequest startRequest;
-        final RecoveryState.Timer timer;
-        try (RecoveryRef recoveryRef = onGoingRecoveries.getRecovery(recoveryId)) {
+        final ReplicationTimer timer;
+        try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.get(recoveryId)) {
             if (recoveryRef == null) {
                 logger.trace("not running recovery with id [{}] - can not find it (probably finished)", recoveryId);
                 return;
@@ -230,28 +244,41 @@ private void doRecovery(final long recoveryId, final StartRecoveryRequest preExi
                     assert recoveryTarget.sourceNode() != null : "can not do a recovery without a source node";
                     logger.trace("{} preparing shard for peer recovery", recoveryTarget.shardId());
                     indexShard.prepareForIndexRecovery();
-                    final long startingSeqNo = indexShard.recoverLocallyUpToGlobalCheckpoint();
+                    final boolean hasRemoteSegmentStore = indexShard.indexSettings().isRemoteStoreEnabled();
+                    if (hasRemoteSegmentStore) {
+                        indexShard.syncSegmentsFromRemoteSegmentStore(false, recoveryTarget::setLastAccessTime);
+                    }
+                    final boolean hasRemoteTranslog = recoveryTarget.state().getPrimary() == false && indexShard.isRemoteTranslogEnabled();
+                    final boolean hasNoTranslog = indexShard.indexSettings().isRemoteSnapshot();
+                    final boolean verifyTranslog = (hasRemoteTranslog || hasNoTranslog || hasRemoteSegmentStore) == false;
+                    final long startingSeqNo = indexShard.recoverLocallyAndFetchStartSeqNo(!hasRemoteTranslog);
                     assert startingSeqNo == UNASSIGNED_SEQ_NO || recoveryTarget.state().getStage() == RecoveryState.Stage.TRANSLOG
                         : "unexpected recovery stage [" + recoveryTarget.state().getStage() + "] starting seqno [ " + startingSeqNo + "]";
-                    startRequest = getStartRecoveryRequest(logger, clusterService.localNode(), recoveryTarget, startingSeqNo);
+                    startRequest = getStartRecoveryRequest(
+                        logger,
+                        clusterService.localNode(),
+                        recoveryTarget,
+                        startingSeqNo,
+                        verifyTranslog
+                    );
                     requestToSend = startRequest;
                     actionName = PeerRecoverySourceService.Actions.START_RECOVERY;
                 } catch (final Exception e) {
                     // this will be logged as warning later on...
-                    logger.trace("unexpected error while preparing shard for peer recovery, failing recovery", e);
-                    onGoingRecoveries.failRecovery(
+                    logger.debug("unexpected error while preparing shard for peer recovery, failing recovery", e);
+                    onGoingRecoveries.fail(
                         recoveryId,
                         new RecoveryFailedException(recoveryTarget.state(), "failed to prepare shard for recovery", e),
                         true
                     );
                     return;
                 }
-                logger.trace("{} starting recovery from {}", startRequest.shardId(), startRequest.sourceNode());
+                logger.debug("{} starting recovery from {}", startRequest.shardId(), startRequest.sourceNode());
             } else {
                 startRequest = preExistingRequest;
                 requestToSend = new ReestablishRecoveryRequest(recoveryId, startRequest.shardId(), startRequest.targetAllocationId());
                 actionName = PeerRecoverySourceService.Actions.REESTABLISH_RECOVERY;
-                logger.trace("{} reestablishing recovery from {}", startRequest.shardId(), startRequest.sourceNode());
+                logger.debug("{} reestablishing recovery from {}", startRequest.shardId(), startRequest.sourceNode());
             }
         }
         transportService.sendRequest(
@@ -262,21 +289,32 @@ private void doRecovery(final long recoveryId, final StartRecoveryRequest preExi
         );
     }
 
+    public static StartRecoveryRequest getStartRecoveryRequest(
+        Logger logger,
+        DiscoveryNode localNode,
+        RecoveryTarget recoveryTarget,
+        long startingSeqNo
+    ) {
+        return getStartRecoveryRequest(logger, localNode, recoveryTarget, startingSeqNo, true);
+    }
+
     /**
      * Prepare the start recovery request.
      *
-     * @param logger         the logger
-     * @param localNode      the local node of the recovery target
-     * @param recoveryTarget the target of the recovery
-     * @param startingSeqNo  a sequence number that an operation-based peer recovery can start with.
-     *                       This is the first operation after the local checkpoint of the safe commit if exists.
+     * @param logger           the logger
+     * @param localNode        the local node of the recovery target
+     * @param recoveryTarget   the target of the recovery
+     * @param startingSeqNo    a sequence number that an operation-based peer recovery can start with.
+     *                         This is the first operation after the local checkpoint of the safe commit if exists.
+     * @param verifyTranslog should the recovery request validate translog consistency with snapshot store metadata.
      * @return a start recovery request
      */
     public static StartRecoveryRequest getStartRecoveryRequest(
         Logger logger,
         DiscoveryNode localNode,
         RecoveryTarget recoveryTarget,
-        long startingSeqNo
+        long startingSeqNo,
+        boolean verifyTranslog
     ) {
         final StartRecoveryRequest request;
         logger.trace("{} collecting local files for [{}]", recoveryTarget.shardId(), recoveryTarget.sourceNode());
@@ -284,22 +322,25 @@ public static StartRecoveryRequest getStartRecoveryRequest(
         Store.MetadataSnapshot metadataSnapshot;
         try {
             metadataSnapshot = recoveryTarget.indexShard().snapshotStoreMetadata();
-            // Make sure that the current translog is consistent with the Lucene index; otherwise, we have to throw away the Lucene index.
-            try {
-                final String expectedTranslogUUID = metadataSnapshot.getCommitUserData().get(Translog.TRANSLOG_UUID_KEY);
-                final long globalCheckpoint = Translog.readGlobalCheckpoint(recoveryTarget.translogLocation(), expectedTranslogUUID);
-                assert globalCheckpoint + 1 >= startingSeqNo : "invalid startingSeqNo " + startingSeqNo + " >= " + globalCheckpoint;
-            } catch (IOException | TranslogCorruptedException e) {
-                logger.warn(
-                    new ParameterizedMessage(
-                        "error while reading global checkpoint from translog, "
-                            + "resetting the starting sequence number from {} to unassigned and recovering as if there are none",
-                        startingSeqNo
-                    ),
-                    e
-                );
-                metadataSnapshot = Store.MetadataSnapshot.EMPTY;
-                startingSeqNo = UNASSIGNED_SEQ_NO;
+            if (verifyTranslog) {
+                // Make sure that the current translog is consistent with the Lucene index; otherwise, we have to throw away the Lucene
+                // index.
+                try {
+                    final String expectedTranslogUUID = metadataSnapshot.getCommitUserData().get(Translog.TRANSLOG_UUID_KEY);
+                    final long globalCheckpoint = Translog.readGlobalCheckpoint(recoveryTarget.translogLocation(), expectedTranslogUUID);
+                    assert globalCheckpoint + 1 >= startingSeqNo : "invalid startingSeqNo " + startingSeqNo + " >= " + globalCheckpoint;
+                } catch (IOException | TranslogCorruptedException e) {
+                    logger.warn(
+                        new ParameterizedMessage(
+                            "error while reading global checkpoint from translog, "
+                                + "resetting the starting sequence number from {} to unassigned and recovering as if there are none",
+                            startingSeqNo
+                        ),
+                        e
+                    );
+                    metadataSnapshot = Store.MetadataSnapshot.EMPTY;
+                    startingSeqNo = UNASSIGNED_SEQ_NO;
+                }
             }
         } catch (final org.apache.lucene.index.IndexNotFoundException e) {
             // happens on an empty folder. no need to log
@@ -330,29 +371,24 @@ public static StartRecoveryRequest getStartRecoveryRequest(
             localNode,
             metadataSnapshot,
             recoveryTarget.state().getPrimary(),
-            recoveryTarget.recoveryId(),
+            recoveryTarget.getId(),
             startingSeqNo
         );
         return request;
     }
 
-    public interface RecoveryListener {
-        void onRecoveryDone(RecoveryState state);
-
-        void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure);
-    }
-
     class PrepareForTranslogOperationsRequestHandler implements TransportRequestHandler<RecoveryPrepareForTranslogOperationsRequest> {
 
         @Override
         public void messageReceived(RecoveryPrepareForTranslogOperationsRequest request, TransportChannel channel, Task task) {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
-                final ActionListener<Void> listener = createOrFinishListener(recoveryRef, channel, Actions.PREPARE_TRANSLOG, request);
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
+                final RecoveryTarget recoveryTarget = recoveryRef.get();
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(channel, Actions.PREPARE_TRANSLOG, request);
                 if (listener == null) {
                     return;
                 }
 
-                recoveryRef.get().prepareForTranslogOperations(request.totalTranslogOps(), listener);
+                recoveryTarget.prepareForTranslogOperations(request.totalTranslogOps(), listener);
             }
         }
     }
@@ -361,13 +397,14 @@ class FinalizeRecoveryRequestHandler implements TransportRequestHandler<Recovery
 
         @Override
         public void messageReceived(RecoveryFinalizeRecoveryRequest request, TransportChannel channel, Task task) throws Exception {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
-                final ActionListener<Void> listener = createOrFinishListener(recoveryRef, channel, Actions.FINALIZE, request);
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
+                final RecoveryTarget recoveryTarget = recoveryRef.get();
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(channel, Actions.FINALIZE, request);
                 if (listener == null) {
                     return;
                 }
 
-                recoveryRef.get().finalizeRecovery(request.globalCheckpoint(), request.trimAboveSeqNo(), listener);
+                recoveryTarget.finalizeRecovery(request.globalCheckpoint(), request.trimAboveSeqNo(), listener);
             }
         }
     }
@@ -377,7 +414,7 @@ class HandoffPrimaryContextRequestHandler implements TransportRequestHandler<Rec
         @Override
         public void messageReceived(final RecoveryHandoffPrimaryContextRequest request, final TransportChannel channel, Task task)
             throws Exception {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
                 recoveryRef.get().handoffPrimaryContext(request.primaryContext());
             }
             channel.sendResponse(TransportResponse.Empty.INSTANCE);
@@ -390,10 +427,9 @@ class TranslogOperationsRequestHandler implements TransportRequestHandler<Recove
         @Override
         public void messageReceived(final RecoveryTranslogOperationsRequest request, final TransportChannel channel, Task task)
             throws IOException {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
                 final RecoveryTarget recoveryTarget = recoveryRef.get();
-                final ActionListener<Void> listener = createOrFinishListener(
-                    recoveryRef,
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(
                     channel,
                     Actions.TRANSLOG_OPS,
                     request,
@@ -410,7 +446,7 @@ public void messageReceived(final RecoveryTranslogOperationsRequest request, fin
         private void performTranslogOps(
             final RecoveryTranslogOperationsRequest request,
             final ActionListener<Void> listener,
-            final RecoveryRef recoveryRef
+            final ReplicationRef<RecoveryTarget> recoveryRef
         ) {
             final RecoveryTarget recoveryTarget = recoveryRef.get();
 
@@ -425,7 +461,12 @@ private void performTranslogOps(
                     @Override
                     public void onNewClusterState(ClusterState state) {
                         threadPool.generic().execute(ActionRunnable.wrap(listener, l -> {
-                            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
+                            try (
+                                ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(
+                                    request.recoveryId(),
+                                    request.shardId()
+                                )
+                            ) {
                                 performTranslogOps(request, listener, recoveryRef);
                             }
                         }));
@@ -471,21 +512,21 @@ class FilesInfoRequestHandler implements TransportRequestHandler<RecoveryFilesIn
 
         @Override
         public void messageReceived(RecoveryFilesInfoRequest request, TransportChannel channel, Task task) throws Exception {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
-                final ActionListener<Void> listener = createOrFinishListener(recoveryRef, channel, Actions.FILES_INFO, request);
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
+                final RecoveryTarget recoveryTarget = recoveryRef.get();
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(channel, Actions.FILES_INFO, request);
                 if (listener == null) {
                     return;
                 }
 
-                recoveryRef.get()
-                    .receiveFileInfo(
-                        request.phase1FileNames,
-                        request.phase1FileSizes,
-                        request.phase1ExistingFileNames,
-                        request.phase1ExistingFileSizes,
-                        request.totalTranslogOps,
-                        listener
-                    );
+                recoveryTarget.receiveFileInfo(
+                    request.phase1FileNames,
+                    request.phase1FileSizes,
+                    request.phase1ExistingFileNames,
+                    request.phase1ExistingFileSizes,
+                    request.totalTranslogOps,
+                    listener
+                );
             }
         }
     }
@@ -494,91 +535,38 @@ class CleanFilesRequestHandler implements TransportRequestHandler<RecoveryCleanF
 
         @Override
         public void messageReceived(RecoveryCleanFilesRequest request, TransportChannel channel, Task task) throws Exception {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
-                final ActionListener<Void> listener = createOrFinishListener(recoveryRef, channel, Actions.CLEAN_FILES, request);
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
+                final RecoveryTarget recoveryTarget = recoveryRef.get();
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(channel, Actions.CLEAN_FILES, request);
                 if (listener == null) {
                     return;
                 }
 
-                recoveryRef.get()
-                    .cleanFiles(request.totalTranslogOps(), request.getGlobalCheckpoint(), request.sourceMetaSnapshot(), listener);
+                recoveryTarget.cleanFiles(
+                    request.totalTranslogOps(),
+                    request.getGlobalCheckpoint(),
+                    request.sourceMetaSnapshot(),
+                    listener
+                );
             }
         }
     }
 
-    class FileChunkTransportRequestHandler implements TransportRequestHandler<RecoveryFileChunkRequest> {
+    class FileChunkTransportRequestHandler implements TransportRequestHandler<FileChunkRequest> {
 
         // How many bytes we've copied since we last called RateLimiter.pause
         final AtomicLong bytesSinceLastPause = new AtomicLong();
 
         @Override
-        public void messageReceived(final RecoveryFileChunkRequest request, TransportChannel channel, Task task) throws Exception {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecoverySafe(request.recoveryId(), request.shardId())) {
+        public void messageReceived(final FileChunkRequest request, TransportChannel channel, Task task) throws Exception {
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.getSafe(request.recoveryId(), request.shardId())) {
                 final RecoveryTarget recoveryTarget = recoveryRef.get();
-                final ActionListener<Void> listener = createOrFinishListener(recoveryRef, channel, Actions.FILE_CHUNK, request);
-                if (listener == null) {
-                    return;
-                }
-
-                final RecoveryState.Index indexState = recoveryTarget.state().getIndex();
-                if (request.sourceThrottleTimeInNanos() != RecoveryState.Index.UNKNOWN) {
-                    indexState.addSourceThrottling(request.sourceThrottleTimeInNanos());
-                }
-
-                RateLimiter rateLimiter = recoverySettings.rateLimiter();
-                if (rateLimiter != null) {
-                    long bytes = bytesSinceLastPause.addAndGet(request.content().length());
-                    if (bytes > rateLimiter.getMinPauseCheckBytes()) {
-                        // Time to pause
-                        bytesSinceLastPause.addAndGet(-bytes);
-                        long throttleTimeInNanos = rateLimiter.pause(bytes);
-                        indexState.addTargetThrottling(throttleTimeInNanos);
-                        recoveryTarget.indexShard().recoveryStats().addThrottleTime(throttleTimeInNanos);
-                    }
-                }
-                recoveryTarget.writeFileChunk(
-                    request.metadata(),
-                    request.position(),
-                    request.content(),
-                    request.lastChunk(),
-                    request.totalTranslogOps(),
-                    listener
-                );
+                final ActionListener<Void> listener = recoveryTarget.createOrFinishListener(channel, Actions.FILE_CHUNK, request);
+                recoveryTarget.handleFileChunk(request, recoveryTarget, bytesSinceLastPause, recoverySettings.rateLimiter(), listener);
             }
         }
     }
 
-    private ActionListener<Void> createOrFinishListener(
-        final RecoveryRef recoveryRef,
-        final TransportChannel channel,
-        final String action,
-        final RecoveryTransportRequest request
-    ) {
-        return createOrFinishListener(recoveryRef, channel, action, request, nullVal -> TransportResponse.Empty.INSTANCE);
-    }
-
-    private ActionListener<Void> createOrFinishListener(
-        final RecoveryRef recoveryRef,
-        final TransportChannel channel,
-        final String action,
-        final RecoveryTransportRequest request,
-        final CheckedFunction<Void, TransportResponse, Exception> responseFn
-    ) {
-        final RecoveryTarget recoveryTarget = recoveryRef.get();
-        final ActionListener<TransportResponse> channelListener = new ChannelActionListener<>(channel, action, request);
-        final ActionListener<Void> voidListener = ActionListener.map(channelListener, responseFn);
-
-        final long requestSeqNo = request.requestSeqNo();
-        final ActionListener<Void> listener;
-        if (requestSeqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
-            listener = recoveryTarget.markRequestReceivedAndCreateListener(requestSeqNo, voidListener);
-        } else {
-            listener = voidListener;
-        }
-
-        return listener;
-    }
-
     class RecoveryRunner extends AbstractRunnable {
 
         final long recoveryId;
@@ -595,10 +583,10 @@ class RecoveryRunner extends AbstractRunnable {
 
         @Override
         public void onFailure(Exception e) {
-            try (RecoveryRef recoveryRef = onGoingRecoveries.getRecovery(recoveryId)) {
+            try (ReplicationRef<RecoveryTarget> recoveryRef = onGoingRecoveries.get(recoveryId)) {
                 if (recoveryRef != null) {
                     logger.error(() -> new ParameterizedMessage("unexpected error during recovery [{}], failing shard", recoveryId), e);
-                    onGoingRecoveries.failRecovery(
+                    onGoingRecoveries.fail(
                         recoveryId,
                         new RecoveryFailedException(recoveryRef.get().state(), "unexpected error", e),
                         true // be safe
@@ -622,9 +610,9 @@ private class RecoveryResponseHandler implements TransportResponseHandler<Recove
 
         private final long recoveryId;
         private final StartRecoveryRequest request;
-        private final RecoveryState.Timer timer;
+        private final ReplicationTimer timer;
 
-        private RecoveryResponseHandler(final StartRecoveryRequest request, final RecoveryState.Timer timer) {
+        private RecoveryResponseHandler(final StartRecoveryRequest request, final ReplicationTimer timer) {
             this.recoveryId = request.recoveryId();
             this.request = request;
             this.timer = timer;
@@ -634,7 +622,7 @@ private RecoveryResponseHandler(final StartRecoveryRequest request, final Recove
         public void handleResponse(RecoveryResponse recoveryResponse) {
             final TimeValue recoveryTime = new TimeValue(timer.time());
             // do this through ongoing recoveries to remove it from the collection
-            onGoingRecoveries.markRecoveryAsDone(recoveryId);
+            onGoingRecoveries.markAsDone(recoveryId);
             if (logger.isTraceEnabled()) {
                 StringBuilder sb = new StringBuilder();
                 sb.append('[')
@@ -695,11 +683,7 @@ private void onException(Exception e) {
             Throwable cause = ExceptionsHelper.unwrapCause(e);
             if (cause instanceof CancellableThreads.ExecutionCancelledException) {
                 // this can also come from the source wrapped in a RemoteTransportException
-                onGoingRecoveries.failRecovery(
-                    recoveryId,
-                    new RecoveryFailedException(request, "source has canceled the recovery", cause),
-                    false
-                );
+                onGoingRecoveries.fail(recoveryId, new RecoveryFailedException(request, "source has canceled the recovery", cause), false);
                 return;
             }
             if (cause instanceof RecoveryEngineException) {
@@ -752,11 +736,11 @@ private void onException(Exception e) {
             }
 
             if (cause instanceof AlreadyClosedException) {
-                onGoingRecoveries.failRecovery(recoveryId, new RecoveryFailedException(request, "source shard is closed", cause), false);
+                onGoingRecoveries.fail(recoveryId, new RecoveryFailedException(request, "source shard is closed", cause), false);
                 return;
             }
 
-            onGoingRecoveries.failRecovery(recoveryId, new RecoveryFailedException(request, e), true);
+            onGoingRecoveries.fail(recoveryId, new RecoveryFailedException(request, e), true);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoverFilesRecoveryException.java b/server/src/main/java/org/opensearch/indices/recovery/RecoverFilesRecoveryException.java
index d3ac3319bf2f0..12e628b9b7e7d 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoverFilesRecoveryException.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoverFilesRecoveryException.java
@@ -34,14 +34,19 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Exception thrown if there is an error recovering files
+ *
+ * @opensearch.internal
+ */
 public class RecoverFilesRecoveryException extends OpenSearchException implements OpenSearchWrapperException {
 
     private final int numberOfFiles;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveriesCollection.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveriesCollection.java
deleted file mode 100644
index 3c197a8e33eb6..0000000000000
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveriesCollection.java
+++ /dev/null
@@ -1,328 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.recovery;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.concurrent.GatedAutoCloseable;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.threadpool.ThreadPool;
-
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
-import java.util.concurrent.ConcurrentMap;
-
-/**
- * This class holds a collection of all on going recoveries on the current node (i.e., the node is the target node
- * of those recoveries). The class is used to guarantee concurrent semantics such that once a recoveries was done/cancelled/failed
- * no other thread will be able to find it. Last, the {@link RecoveryRef} inner class verifies that recovery temporary files
- * and store will only be cleared once on going usage is finished.
- */
-public class RecoveriesCollection {
-
-    /** This is the single source of truth for ongoing recoveries. If it's not here, it was canceled or done */
-    private final ConcurrentMap<Long, RecoveryTarget> onGoingRecoveries = ConcurrentCollections.newConcurrentMap();
-
-    private final Logger logger;
-    private final ThreadPool threadPool;
-
-    public RecoveriesCollection(Logger logger, ThreadPool threadPool) {
-        this.logger = logger;
-        this.threadPool = threadPool;
-    }
-
-    /**
-     * Starts are new recovery for the given shard, source node and state
-     *
-     * @return the id of the new recovery.
-     */
-    public long startRecovery(
-        IndexShard indexShard,
-        DiscoveryNode sourceNode,
-        PeerRecoveryTargetService.RecoveryListener listener,
-        TimeValue activityTimeout
-    ) {
-        RecoveryTarget recoveryTarget = new RecoveryTarget(indexShard, sourceNode, listener);
-        startRecoveryInternal(recoveryTarget, activityTimeout);
-        return recoveryTarget.recoveryId();
-    }
-
-    private void startRecoveryInternal(RecoveryTarget recoveryTarget, TimeValue activityTimeout) {
-        RecoveryTarget existingTarget = onGoingRecoveries.putIfAbsent(recoveryTarget.recoveryId(), recoveryTarget);
-        assert existingTarget == null : "found two RecoveryStatus instances with the same id";
-        logger.trace(
-            "{} started recovery from {}, id [{}]",
-            recoveryTarget.shardId(),
-            recoveryTarget.sourceNode(),
-            recoveryTarget.recoveryId()
-        );
-        threadPool.schedule(
-            new RecoveryMonitor(recoveryTarget.recoveryId(), recoveryTarget.lastAccessTime(), activityTimeout),
-            activityTimeout,
-            ThreadPool.Names.GENERIC
-        );
-    }
-
-    /**
-     * Resets the recovery and performs a recovery restart on the currently recovering index shard
-     *
-     * @see IndexShard#performRecoveryRestart()
-     * @return newly created RecoveryTarget
-     */
-    public RecoveryTarget resetRecovery(final long recoveryId, final TimeValue activityTimeout) {
-        RecoveryTarget oldRecoveryTarget = null;
-        final RecoveryTarget newRecoveryTarget;
-
-        try {
-            synchronized (onGoingRecoveries) {
-                // swap recovery targets in a synchronized block to ensure that the newly added recovery target is picked up by
-                // cancelRecoveriesForShard whenever the old recovery target is picked up
-                oldRecoveryTarget = onGoingRecoveries.remove(recoveryId);
-                if (oldRecoveryTarget == null) {
-                    return null;
-                }
-
-                newRecoveryTarget = oldRecoveryTarget.retryCopy();
-                startRecoveryInternal(newRecoveryTarget, activityTimeout);
-            }
-
-            // Closes the current recovery target
-            boolean successfulReset = oldRecoveryTarget.resetRecovery(newRecoveryTarget.cancellableThreads());
-            if (successfulReset) {
-                logger.trace(
-                    "{} restarted recovery from {}, id [{}], previous id [{}]",
-                    newRecoveryTarget.shardId(),
-                    newRecoveryTarget.sourceNode(),
-                    newRecoveryTarget.recoveryId(),
-                    oldRecoveryTarget.recoveryId()
-                );
-                return newRecoveryTarget;
-            } else {
-                logger.trace(
-                    "{} recovery could not be reset as it is already cancelled, recovery from {}, id [{}], previous id [{}]",
-                    newRecoveryTarget.shardId(),
-                    newRecoveryTarget.sourceNode(),
-                    newRecoveryTarget.recoveryId(),
-                    oldRecoveryTarget.recoveryId()
-                );
-                cancelRecovery(newRecoveryTarget.recoveryId(), "recovery cancelled during reset");
-                return null;
-            }
-        } catch (Exception e) {
-            // fail shard to be safe
-            oldRecoveryTarget.notifyListener(new RecoveryFailedException(oldRecoveryTarget.state(), "failed to retry recovery", e), true);
-            return null;
-        }
-    }
-
-    public RecoveryTarget getRecoveryTarget(long id) {
-        return onGoingRecoveries.get(id);
-    }
-
-    /**
-     * gets the {@link RecoveryTarget } for a given id. The RecoveryStatus returned has it's ref count already incremented
-     * to make sure it's safe to use. However, you must call {@link RecoveryTarget#decRef()} when you are done with it, typically
-     * by using this method in a try-with-resources clause.
-     * <p>
-     * Returns null if recovery is not found
-     */
-    public RecoveryRef getRecovery(long id) {
-        RecoveryTarget status = onGoingRecoveries.get(id);
-        if (status != null && status.tryIncRef()) {
-            return new RecoveryRef(status);
-        }
-        return null;
-    }
-
-    /** Similar to {@link #getRecovery(long)} but throws an exception if no recovery is found */
-    public RecoveryRef getRecoverySafe(long id, ShardId shardId) {
-        RecoveryRef recoveryRef = getRecovery(id);
-        if (recoveryRef == null) {
-            throw new IndexShardClosedException(shardId);
-        }
-        assert recoveryRef.get().shardId().equals(shardId);
-        return recoveryRef;
-    }
-
-    /** cancel the recovery with the given id (if found) and remove it from the recovery collection */
-    public boolean cancelRecovery(long id, String reason) {
-        RecoveryTarget removed = onGoingRecoveries.remove(id);
-        boolean cancelled = false;
-        if (removed != null) {
-            logger.trace(
-                "{} canceled recovery from {}, id [{}] (reason [{}])",
-                removed.shardId(),
-                removed.sourceNode(),
-                removed.recoveryId(),
-                reason
-            );
-            removed.cancel(reason);
-            cancelled = true;
-        }
-        return cancelled;
-    }
-
-    /**
-     * fail the recovery with the given id (if found) and remove it from the recovery collection
-     *
-     * @param id               id of the recovery to fail
-     * @param e                exception with reason for the failure
-     * @param sendShardFailure true a shard failed message should be sent to the master
-     */
-    public void failRecovery(long id, RecoveryFailedException e, boolean sendShardFailure) {
-        RecoveryTarget removed = onGoingRecoveries.remove(id);
-        if (removed != null) {
-            logger.trace(
-                "{} failing recovery from {}, id [{}]. Send shard failure: [{}]",
-                removed.shardId(),
-                removed.sourceNode(),
-                removed.recoveryId(),
-                sendShardFailure
-            );
-            removed.fail(e, sendShardFailure);
-        }
-    }
-
-    /** mark the recovery with the given id as done (if found) */
-    public void markRecoveryAsDone(long id) {
-        RecoveryTarget removed = onGoingRecoveries.remove(id);
-        if (removed != null) {
-            logger.trace("{} marking recovery from {} as done, id [{}]", removed.shardId(), removed.sourceNode(), removed.recoveryId());
-            removed.markAsDone();
-        }
-    }
-
-    /** the number of ongoing recoveries */
-    public int size() {
-        return onGoingRecoveries.size();
-    }
-
-    /**
-     * cancel all ongoing recoveries for the given shard
-     *
-     * @param reason       reason for cancellation
-     * @param shardId      shardId for which to cancel recoveries
-     * @return true if a recovery was cancelled
-     */
-    public boolean cancelRecoveriesForShard(ShardId shardId, String reason) {
-        boolean cancelled = false;
-        List<RecoveryTarget> matchedRecoveries = new ArrayList<>();
-        synchronized (onGoingRecoveries) {
-            for (Iterator<RecoveryTarget> it = onGoingRecoveries.values().iterator(); it.hasNext();) {
-                RecoveryTarget status = it.next();
-                if (status.shardId().equals(shardId)) {
-                    matchedRecoveries.add(status);
-                    it.remove();
-                }
-            }
-        }
-        for (RecoveryTarget removed : matchedRecoveries) {
-            logger.trace(
-                "{} canceled recovery from {}, id [{}] (reason [{}])",
-                removed.shardId(),
-                removed.sourceNode(),
-                removed.recoveryId(),
-                reason
-            );
-            removed.cancel(reason);
-            cancelled = true;
-        }
-        return cancelled;
-    }
-
-    /**
-     * a reference to {@link RecoveryTarget}, which implements {@link AutoCloseable}. closing the reference
-     * causes {@link RecoveryTarget#decRef()} to be called. This makes sure that the underlying resources
-     * will not be freed until {@link RecoveryRef#close()} is called.
-     */
-    public static class RecoveryRef extends GatedAutoCloseable<RecoveryTarget> {
-
-        /**
-         * Important: {@link RecoveryTarget#tryIncRef()} should
-         * be *successfully* called on status before
-         */
-        public RecoveryRef(RecoveryTarget status) {
-            super(status, status::decRef);
-            status.setLastAccessTime();
-        }
-    }
-
-    private class RecoveryMonitor extends AbstractRunnable {
-        private final long recoveryId;
-        private final TimeValue checkInterval;
-
-        private volatile long lastSeenAccessTime;
-
-        private RecoveryMonitor(long recoveryId, long lastSeenAccessTime, TimeValue checkInterval) {
-            this.recoveryId = recoveryId;
-            this.checkInterval = checkInterval;
-            this.lastSeenAccessTime = lastSeenAccessTime;
-        }
-
-        @Override
-        public void onFailure(Exception e) {
-            logger.error(() -> new ParameterizedMessage("unexpected error while monitoring recovery [{}]", recoveryId), e);
-        }
-
-        @Override
-        protected void doRun() throws Exception {
-            RecoveryTarget status = onGoingRecoveries.get(recoveryId);
-            if (status == null) {
-                logger.trace("[monitor] no status found for [{}], shutting down", recoveryId);
-                return;
-            }
-            long accessTime = status.lastAccessTime();
-            if (accessTime == lastSeenAccessTime) {
-                String message = "no activity after [" + checkInterval + "]";
-                failRecovery(
-                    recoveryId,
-                    new RecoveryFailedException(status.state(), message, new OpenSearchTimeoutException(message)),
-                    true // to be safe, we don't know what go stuck
-                );
-                return;
-            }
-            lastSeenAccessTime = accessTime;
-            logger.trace("[monitor] rescheduling check for [{}]. last access time is [{}]", recoveryId, lastSeenAccessTime);
-            threadPool.schedule(this, checkInterval, ThreadPool.Names.GENERIC);
-        }
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryCleanFilesRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryCleanFilesRequest.java
index 974bba9673d43..048f0b7cc1f20 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryCleanFilesRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryCleanFilesRequest.java
@@ -33,14 +33,19 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 
 import java.io.IOException;
 
+/**
+ * Request to clean up recovery files
+ *
+ * @opensearch.internal
+ */
 public class RecoveryCleanFilesRequest extends RecoveryTransportRequest {
 
     private final long recoveryId;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFailedException.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFailedException.java
index 5293286269659..73916d0238419 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFailedException.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFailedException.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
 
 import java.io.IOException;
 
-public class RecoveryFailedException extends OpenSearchException {
+/**
+ * Exception thrown if recovery fails
+ *
+ * @opensearch.internal
+ */
+public class RecoveryFailedException extends ReplicationFailedException {
 
     public RecoveryFailedException(StartRecoveryRequest request, Throwable cause) {
         this(request, null, cause);
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFileChunkRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFileChunkRequest.java
deleted file mode 100644
index 2a0357547048a..0000000000000
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFileChunkRequest.java
+++ /dev/null
@@ -1,158 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.recovery;
-
-import org.apache.lucene.util.Version;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.lucene.Lucene;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.store.StoreFileMetadata;
-
-import java.io.IOException;
-
-public final class RecoveryFileChunkRequest extends RecoveryTransportRequest {
-    private final boolean lastChunk;
-    private final long recoveryId;
-    private final ShardId shardId;
-    private final long position;
-    private final BytesReference content;
-    private final StoreFileMetadata metadata;
-    private final long sourceThrottleTimeInNanos;
-
-    private final int totalTranslogOps;
-
-    public RecoveryFileChunkRequest(StreamInput in) throws IOException {
-        super(in);
-        recoveryId = in.readLong();
-        shardId = new ShardId(in);
-        String name = in.readString();
-        position = in.readVLong();
-        long length = in.readVLong();
-        String checksum = in.readString();
-        content = in.readBytesReference();
-        Version writtenBy = Lucene.parseVersionLenient(in.readString(), null);
-        assert writtenBy != null;
-        metadata = new StoreFileMetadata(name, length, checksum, writtenBy);
-        lastChunk = in.readBoolean();
-        totalTranslogOps = in.readVInt();
-        sourceThrottleTimeInNanos = in.readLong();
-    }
-
-    public RecoveryFileChunkRequest(
-        long recoveryId,
-        final long requestSeqNo,
-        ShardId shardId,
-        StoreFileMetadata metadata,
-        long position,
-        BytesReference content,
-        boolean lastChunk,
-        int totalTranslogOps,
-        long sourceThrottleTimeInNanos
-    ) {
-        super(requestSeqNo);
-        this.recoveryId = recoveryId;
-        this.shardId = shardId;
-        this.metadata = metadata;
-        this.position = position;
-        this.content = content;
-        this.lastChunk = lastChunk;
-        this.totalTranslogOps = totalTranslogOps;
-        this.sourceThrottleTimeInNanos = sourceThrottleTimeInNanos;
-    }
-
-    public long recoveryId() {
-        return this.recoveryId;
-    }
-
-    public ShardId shardId() {
-        return shardId;
-    }
-
-    public String name() {
-        return metadata.name();
-    }
-
-    public long position() {
-        return position;
-    }
-
-    public long length() {
-        return metadata.length();
-    }
-
-    public BytesReference content() {
-        return content;
-    }
-
-    public int totalTranslogOps() {
-        return totalTranslogOps;
-    }
-
-    public long sourceThrottleTimeInNanos() {
-        return sourceThrottleTimeInNanos;
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        super.writeTo(out);
-        out.writeLong(recoveryId);
-        shardId.writeTo(out);
-        out.writeString(metadata.name());
-        out.writeVLong(position);
-        out.writeVLong(metadata.length());
-        out.writeString(metadata.checksum());
-        out.writeBytesReference(content);
-        out.writeString(metadata.writtenBy().toString());
-        out.writeBoolean(lastChunk);
-        out.writeVInt(totalTranslogOps);
-        out.writeLong(sourceThrottleTimeInNanos);
-    }
-
-    @Override
-    public String toString() {
-        return shardId + ": name='" + name() + '\'' + ", position=" + position + ", length=" + length();
-    }
-
-    public StoreFileMetadata metadata() {
-        return metadata;
-    }
-
-    /**
-     * Returns <code>true</code> if this chunk is the last chunk in the stream.
-     */
-    public boolean lastChunk() {
-        return lastChunk;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFilesInfoRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFilesInfoRequest.java
index 6c1b29e155dd0..d0fefe3d51f33 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFilesInfoRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFilesInfoRequest.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Request for recovery file information
+ *
+ * @opensearch.internal
+ */
 public class RecoveryFilesInfoRequest extends RecoveryTransportRequest {
 
     private long recoveryId;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFinalizeRecoveryRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFinalizeRecoveryRequest.java
index f3ef74e1fdf59..069cd0670f7ba 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryFinalizeRecoveryRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryFinalizeRecoveryRequest.java
@@ -33,13 +33,18 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Request to finalize recovery
+ *
+ * @opensearch.internal
+ */
 final class RecoveryFinalizeRecoveryRequest extends RecoveryTransportRequest {
 
     private final long recoveryId;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryHandoffPrimaryContextRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryHandoffPrimaryContextRequest.java
index 048de6edade73..c7fad7b12f10b 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryHandoffPrimaryContextRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryHandoffPrimaryContextRequest.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.ReplicationTracker;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
 /**
  * The request object to handoff the primary context to the relocation target.
+ *
+ * @opensearch.internal
  */
 class RecoveryHandoffPrimaryContextRequest extends TransportRequest {
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryListener.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryListener.java
new file mode 100644
index 0000000000000..c8c2fbfc896eb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryListener.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.indices.cluster.IndicesClusterStateService;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+
+/**
+ * Listener that runs on changes in Recovery state
+ *
+ * @opensearch.internal
+ */
+public class RecoveryListener implements ReplicationListener {
+
+    /**
+     * ShardRouting with which the shard was created
+     */
+    private final ShardRouting shardRouting;
+
+    /**
+     * Primary term with which the shard was created
+     */
+    private final long primaryTerm;
+
+    private final IndicesClusterStateService indicesClusterStateService;
+
+    public RecoveryListener(
+        final ShardRouting shardRouting,
+        final long primaryTerm,
+        IndicesClusterStateService indicesClusterStateService
+    ) {
+        this.shardRouting = shardRouting;
+        this.primaryTerm = primaryTerm;
+        this.indicesClusterStateService = indicesClusterStateService;
+    }
+
+    @Override
+    public void onDone(ReplicationState state) {
+        indicesClusterStateService.handleRecoveryDone(state, shardRouting, primaryTerm);
+    }
+
+    @Override
+    public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+        indicesClusterStateService.handleRecoveryFailure(shardRouting, sendShardFailure, e);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryPrepareForTranslogOperationsRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryPrepareForTranslogOperationsRequest.java
index 579643bd62763..8c861337031ab 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryPrepareForTranslogOperationsRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryPrepareForTranslogOperationsRequest.java
@@ -33,12 +33,17 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 
+/**
+ * Request to prepare cluster for translog operations
+ *
+ * @opensearch.internal
+ */
 class RecoveryPrepareForTranslogOperationsRequest extends RecoveryTransportRequest {
 
     private final long recoveryId;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryRequestTracker.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryRequestTracker.java
deleted file mode 100644
index 048a8019d2cda..0000000000000
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryRequestTracker.java
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.recovery;
-
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.Nullable;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.ListenableFuture;
-import org.opensearch.index.seqno.LocalCheckpointTracker;
-
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-
-import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
-
-public class RecoveryRequestTracker {
-
-    private final Map<Long, ListenableFuture<Void>> ongoingRequests = Collections.synchronizedMap(new HashMap<>());
-    private final LocalCheckpointTracker checkpointTracker = new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED);
-
-    /**
-     * This method will mark that a request with a unique sequence number has been received. If this is the
-     * first time the unique request has been received, this method will return a listener to be completed.
-     * The caller should then perform the requested action and complete the returned listener.
-     *
-     *
-     * If the unique request has already been received, this method will either complete the provided listener
-     * or attach that listener to the listener returned in the first call. In this case, the method will
-     * return null and the caller should not perform the requested action as a prior caller is already
-     * performing the action.
-     */
-    @Nullable
-    public synchronized ActionListener<Void> markReceivedAndCreateListener(long requestSeqNo, ActionListener<Void> listener) {
-        if (checkpointTracker.hasProcessed(requestSeqNo)) {
-            final ListenableFuture<Void> existingFuture = ongoingRequests.get(requestSeqNo);
-            if (existingFuture != null) {
-                existingFuture.addListener(listener, OpenSearchExecutors.newDirectExecutorService());
-            } else {
-                listener.onResponse(null);
-            }
-            return null;
-        } else {
-            checkpointTracker.markSeqNoAsProcessed(requestSeqNo);
-            final ListenableFuture<Void> future = new ListenableFuture<>();
-            ongoingRequests.put(requestSeqNo, future);
-            future.addListener(new ActionListener<Void>() {
-                @Override
-                public void onResponse(Void v) {
-                    ongoingRequests.remove(requestSeqNo);
-                    listener.onResponse(v);
-                }
-
-                @Override
-                public void onFailure(Exception e) {
-                    // We do not remove the future to cache the error for retried requests
-                    listener.onFailure(e);
-                }
-            }, OpenSearchExecutors.newDirectExecutorService());
-            return future;
-        }
-    }
-}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryResponse.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryResponse.java
index f316606dcb9a9..c1203a9f4939f 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryResponse.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryResponse.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Response for recovery operations
+ *
+ * @opensearch.internal
+ */
 public final class RecoveryResponse extends TransportResponse {
 
     final List<String> phase1FileNames;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoverySettings.java b/server/src/main/java/org/opensearch/indices/recovery/RecoverySettings.java
index 127127f5feace..ed9755bf824ea 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoverySettings.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoverySettings.java
@@ -40,10 +40,15 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
+/**
+ * Settings for the recovery mechanism
+ *
+ * @opensearch.internal
+ */
 public class RecoverySettings {
 
     private static final Logger logger = LogManager.getLogger(RecoverySettings.class);
@@ -79,6 +84,17 @@ public class RecoverySettings {
         Property.NodeScope
     );
 
+    /**
+     * Controls the maximum number of streams that can be started concurrently when downloading from the remote store.
+     */
+    public static final Setting<Integer> INDICES_RECOVERY_MAX_CONCURRENT_REMOTE_STORE_STREAMS_SETTING = Setting.intSetting(
+        "indices.recovery.max_concurrent_remote_store_streams",
+        20,
+        1,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     /**
      * how long to wait before retrying after issues cause by cluster state syncing between nodes
      * i.e., local node is not yet known on remote node, remote shard not yet started etc.
@@ -144,6 +160,7 @@ public class RecoverySettings {
     private volatile ByteSizeValue maxBytesPerSec;
     private volatile int maxConcurrentFileChunks;
     private volatile int maxConcurrentOperations;
+    private volatile int maxConcurrentRemoteStoreStreams;
     private volatile SimpleRateLimiter rateLimiter;
     private volatile TimeValue retryDelayStateSync;
     private volatile TimeValue retryDelayNetwork;
@@ -158,8 +175,9 @@ public RecoverySettings(Settings settings, ClusterSettings clusterSettings) {
         this.retryDelayStateSync = INDICES_RECOVERY_RETRY_DELAY_STATE_SYNC_SETTING.get(settings);
         this.maxConcurrentFileChunks = INDICES_RECOVERY_MAX_CONCURRENT_FILE_CHUNKS_SETTING.get(settings);
         this.maxConcurrentOperations = INDICES_RECOVERY_MAX_CONCURRENT_OPERATIONS_SETTING.get(settings);
+        this.maxConcurrentRemoteStoreStreams = INDICES_RECOVERY_MAX_CONCURRENT_REMOTE_STORE_STREAMS_SETTING.get(settings);
         // doesn't have to be fast as nodes are reconnected every 10s by default (see InternalClusterService.ReconnectToNodes)
-        // and we want to give the master time to remove a faulty node
+        // and we want to give the cluster-manager time to remove a faulty node
         this.retryDelayNetwork = INDICES_RECOVERY_RETRY_DELAY_NETWORK_SETTING.get(settings);
 
         this.internalActionTimeout = INDICES_RECOVERY_INTERNAL_ACTION_TIMEOUT_SETTING.get(settings);
@@ -179,6 +197,10 @@ public RecoverySettings(Settings settings, ClusterSettings clusterSettings) {
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING, this::setMaxBytesPerSec);
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_MAX_CONCURRENT_FILE_CHUNKS_SETTING, this::setMaxConcurrentFileChunks);
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_MAX_CONCURRENT_OPERATIONS_SETTING, this::setMaxConcurrentOperations);
+        clusterSettings.addSettingsUpdateConsumer(
+            INDICES_RECOVERY_MAX_CONCURRENT_REMOTE_STORE_STREAMS_SETTING,
+            this::setMaxConcurrentRemoteStoreStreams
+        );
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_RETRY_DELAY_STATE_SYNC_SETTING, this::setRetryDelayStateSync);
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_RETRY_DELAY_NETWORK_SETTING, this::setRetryDelayNetwork);
         clusterSettings.addSettingsUpdateConsumer(INDICES_RECOVERY_INTERNAL_ACTION_TIMEOUT_SETTING, this::setInternalActionTimeout);
@@ -274,4 +296,12 @@ public int getMaxConcurrentOperations() {
     private void setMaxConcurrentOperations(int maxConcurrentOperations) {
         this.maxConcurrentOperations = maxConcurrentOperations;
     }
+
+    public int getMaxConcurrentRemoteStoreStreams() {
+        return this.maxConcurrentRemoteStoreStreams;
+    }
+
+    private void setMaxConcurrentRemoteStoreStreams(int maxConcurrentRemoteStoreStreams) {
+        this.maxConcurrentRemoteStoreStreams = maxConcurrentRemoteStoreStreams;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandler.java b/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandler.java
index 77596f50a8a5e..7d7e2f6114129 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandler.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandler.java
@@ -33,70 +33,55 @@
 package org.opensearch.indices.recovery;
 
 import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexFormatTooNewException;
 import org.apache.lucene.index.IndexFormatTooOldException;
-import org.apache.lucene.store.IOContext;
-import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.store.RateLimiter;
 import org.apache.lucene.util.ArrayUtil;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.ThreadedActionListener;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.StopWatch;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.logging.Loggers;
-import org.opensearch.common.lucene.store.InputStreamIndexInput;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.concurrent.FutureUtils;
 import org.opensearch.common.util.concurrent.ListenableFuture;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.engine.RecoveryEngineException;
-import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLease;
 import org.opensearch.index.seqno.RetentionLeaseNotFoundException;
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.IndexShardRelocatedException;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.RunUnderPrimaryPermit;
+import org.opensearch.indices.replication.SegmentFileTransferHandler;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.RemoteTransportException;
 import org.opensearch.transport.Transports;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
-import java.util.Deque;
 import java.util.List;
 import java.util.Locale;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ConcurrentLinkedDeque;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -109,32 +94,34 @@
  * RecoverySourceHandler handles the three phases of shard recovery, which is
  * everything relating to copying the segment files as well as sending translog
  * operations across the wire once the segments have been copied.
- *
+ * <p>
  * Note: There is always one source handler per recovery that handles all the
  * file and translog transfer. This handler is completely isolated from other recoveries
  * while the {@link RateLimiter} passed via {@link RecoverySettings} is shared across recoveries
  * originating from this nodes to throttle the number bytes send during file transfer. The transaction log
  * phase bypasses the rate limiter entirely.
+ *
+ * @opensearch.internal
  */
-public class RecoverySourceHandler {
+public abstract class RecoverySourceHandler {
 
     protected final Logger logger;
     // Shard that is going to be recovered (the "source")
-    private final IndexShard shard;
-    private final int shardId;
+    protected final IndexShard shard;
+    protected final int shardId;
     // Request containing source and target node information
-    private final StartRecoveryRequest request;
+    protected final StartRecoveryRequest request;
     private final int chunkSizeInBytes;
     private final RecoveryTargetHandler recoveryTarget;
-    private final int maxConcurrentFileChunks;
     private final int maxConcurrentOperations;
     private final ThreadPool threadPool;
-    private final CancellableThreads cancellableThreads = new CancellableThreads();
-    private final List<Closeable> resources = new CopyOnWriteArrayList<>();
-    private final ListenableFuture<RecoveryResponse> future = new ListenableFuture<>();
+    protected final CancellableThreads cancellableThreads = new CancellableThreads();
+    protected final List<Closeable> resources = new CopyOnWriteArrayList<>();
+    protected final ListenableFuture<RecoveryResponse> future = new ListenableFuture<>();
     public static final String PEER_RECOVERY_NAME = "peer-recovery";
+    private final SegmentFileTransferHandler transferHandler;
 
-    public RecoverySourceHandler(
+    RecoverySourceHandler(
         IndexShard shard,
         RecoveryTargetHandler recoveryTarget,
         ThreadPool threadPool,
@@ -143,15 +130,24 @@ public RecoverySourceHandler(
         int maxConcurrentFileChunks,
         int maxConcurrentOperations
     ) {
+        this.logger = Loggers.getLogger(RecoverySourceHandler.class, request.shardId(), "recover to " + request.targetNode().getName());
+        this.transferHandler = new SegmentFileTransferHandler(
+            shard,
+            request.targetNode(),
+            recoveryTarget,
+            logger,
+            threadPool,
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
         this.shard = shard;
-        this.recoveryTarget = recoveryTarget;
         this.threadPool = threadPool;
         this.request = request;
+        this.recoveryTarget = recoveryTarget;
         this.shardId = this.request.shardId().id();
-        this.logger = Loggers.getLogger(getClass(), request.shardId(), "recover to " + request.targetNode().getName());
         this.chunkSizeInBytes = fileChunkSizeInBytes;
         // if the target is on an old version, it won't be able to handle out-of-order file chunks.
-        this.maxConcurrentFileChunks = maxConcurrentFileChunks;
         this.maxConcurrentOperations = maxConcurrentOperations;
     }
 
@@ -184,226 +180,77 @@ public void recoverToTarget(ActionListener<RecoveryResponse> listener) {
                 throw e;
             });
             final Consumer<Exception> onFailure = e -> {
-                assert Transports.assertNotTransportThread(RecoverySourceHandler.this + "[onFailure]");
+                assert Transports.assertNotTransportThread(this + "[onFailure]");
                 IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
             };
+            innerRecoveryToTarget(listener, onFailure);
+        } catch (Exception e) {
+            IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
+        }
+    }
 
-            final SetOnce<RetentionLease> retentionLeaseRef = new SetOnce<>();
+    protected abstract void innerRecoveryToTarget(ActionListener<RecoveryResponse> listener, Consumer<Exception> onFailure)
+        throws IOException;
 
-            runUnderPrimaryPermit(() -> {
-                final IndexShardRoutingTable routingTable = shard.getReplicationGroup().getRoutingTable();
-                ShardRouting targetShardRouting = routingTable.getByAllocationId(request.targetAllocationId());
-                if (targetShardRouting == null) {
-                    logger.debug(
-                        "delaying recovery of {} as it is not listed as assigned to target node {}",
-                        request.shardId(),
-                        request.targetNode()
-                    );
-                    throw new DelayRecoveryException("source node does not have the shard listed in its state as allocated on the node");
-                }
-                assert targetShardRouting.initializing() : "expected recovery target to be initializing but was " + targetShardRouting;
-                retentionLeaseRef.set(
-                    shard.getRetentionLeases().get(ReplicationTracker.getPeerRecoveryRetentionLeaseId(targetShardRouting))
-                );
-            },
-                shardId + " validating recovery target [" + request.targetAllocationId() + "] registered ",
-                shard,
-                cancellableThreads,
-                logger
+    protected void finalizeStepAndCompleteFuture(
+        long startingSeqNo,
+        StepListener<SendSnapshotResult> sendSnapshotStep,
+        StepListener<SendFileResult> sendFileStep,
+        StepListener<TimeValue> prepareEngineStep,
+        Consumer<Exception> onFailure
+    ) {
+        final StepListener<Void> finalizeStep = new StepListener<>();
+        // Recovery target can trim all operations >= startingSeqNo as we have sent all these operations in the phase 2
+        final long trimAboveSeqNo = startingSeqNo - 1;
+        sendSnapshotStep.whenComplete(r -> {
+            logger.debug("sendSnapshotStep completed");
+            finalizeRecovery(r.targetLocalCheckpoint, trimAboveSeqNo, finalizeStep);
+        }, onFailure);
+
+        finalizeStep.whenComplete(r -> {
+            logger.debug("finalizeStep completed");
+            final long phase1ThrottlingWaitTime = 0L; // TODO: return the actual throttle time
+            final SendSnapshotResult sendSnapshotResult = sendSnapshotStep.result();
+            final SendFileResult sendFileResult = sendFileStep.result();
+            final RecoveryResponse response = new RecoveryResponse(
+                sendFileResult.phase1FileNames,
+                sendFileResult.phase1FileSizes,
+                sendFileResult.phase1ExistingFileNames,
+                sendFileResult.phase1ExistingFileSizes,
+                sendFileResult.totalSize,
+                sendFileResult.existingTotalSize,
+                sendFileResult.took.millis(),
+                phase1ThrottlingWaitTime,
+                prepareEngineStep.result().millis(),
+                sendSnapshotResult.sentOperations,
+                sendSnapshotResult.tookTime.millis()
             );
-            final Closeable retentionLock = shard.acquireHistoryRetentionLock();
-            resources.add(retentionLock);
-            final long startingSeqNo;
-            final boolean isSequenceNumberBasedRecovery = request.startingSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO
-                && isTargetSameHistory()
-                && shard.hasCompleteHistoryOperations(PEER_RECOVERY_NAME, request.startingSeqNo())
-                && ((retentionLeaseRef.get() == null && shard.useRetentionLeasesInPeerRecovery() == false)
-                    || (retentionLeaseRef.get() != null && retentionLeaseRef.get().retainingSequenceNumber() <= request.startingSeqNo()));
-            // NB check hasCompleteHistoryOperations when computing isSequenceNumberBasedRecovery, even if there is a retention lease,
-            // because when doing a rolling upgrade from earlier than 7.4 we may create some leases that are initially unsatisfied. It's
-            // possible there are other cases where we cannot satisfy all leases, because that's not a property we currently expect to hold.
-            // Also it's pretty cheap when soft deletes are enabled, and it'd be a disaster if we tried a sequence-number-based recovery
-            // without having a complete history.
-
-            if (isSequenceNumberBasedRecovery && retentionLeaseRef.get() != null) {
-                // all the history we need is retained by an existing retention lease, so we do not need a separate retention lock
-                retentionLock.close();
-                logger.trace("history is retained by {}", retentionLeaseRef.get());
-            } else {
-                // all the history we need is retained by the retention lock, obtained before calling shard.hasCompleteHistoryOperations()
-                // and before acquiring the safe commit we'll be using, so we can be certain that all operations after the safe commit's
-                // local checkpoint will be retained for the duration of this recovery.
-                logger.trace("history is retained by retention lock");
+            try {
+                future.onResponse(response);
+            } finally {
+                IOUtils.close(resources);
             }
+        }, onFailure);
+    }
 
-            final StepListener<SendFileResult> sendFileStep = new StepListener<>();
-            final StepListener<TimeValue> prepareEngineStep = new StepListener<>();
-            final StepListener<SendSnapshotResult> sendSnapshotStep = new StepListener<>();
-            final StepListener<Void> finalizeStep = new StepListener<>();
-
-            if (isSequenceNumberBasedRecovery) {
-                logger.trace("performing sequence numbers based recovery. starting at [{}]", request.startingSeqNo());
-                startingSeqNo = request.startingSeqNo();
-                if (retentionLeaseRef.get() == null) {
-                    createRetentionLease(startingSeqNo, ActionListener.map(sendFileStep, ignored -> SendFileResult.EMPTY));
-                } else {
-                    sendFileStep.onResponse(SendFileResult.EMPTY);
-                }
-            } else {
-                final GatedCloseable<IndexCommit> wrappedSafeCommit;
-                try {
-                    wrappedSafeCommit = acquireSafeCommit(shard);
-                    resources.add(wrappedSafeCommit);
-                } catch (final Exception e) {
-                    throw new RecoveryEngineException(shard.shardId(), 1, "snapshot failed", e);
-                }
-
-                // Try and copy enough operations to the recovering peer so that if it is promoted to primary then it has a chance of being
-                // able to recover other replicas using operations-based recoveries. If we are not using retention leases then we
-                // conservatively copy all available operations. If we are using retention leases then "enough operations" is just the
-                // operations from the local checkpoint of the safe commit onwards, because when using soft deletes the safe commit retains
-                // at least as much history as anything else. The safe commit will often contain all the history retained by the current set
-                // of retention leases, but this is not guaranteed: an earlier peer recovery from a different primary might have created a
-                // retention lease for some history that this primary already discarded, since we discard history when the global checkpoint
-                // advances and not when creating a new safe commit. In any case this is a best-effort thing since future recoveries can
-                // always fall back to file-based ones, and only really presents a problem if this primary fails before things have settled
-                // down.
-                startingSeqNo = Long.parseLong(wrappedSafeCommit.get().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)) + 1L;
-                logger.trace("performing file-based recovery followed by history replay starting at [{}]", startingSeqNo);
-
-                try {
-                    final int estimateNumOps = countNumberOfHistoryOperations(startingSeqNo);
-                    final Releasable releaseStore = acquireStore(shard.store());
-                    resources.add(releaseStore);
-                    sendFileStep.whenComplete(r -> IOUtils.close(wrappedSafeCommit, releaseStore), e -> {
-                        try {
-                            IOUtils.close(wrappedSafeCommit, releaseStore);
-                        } catch (final IOException ex) {
-                            logger.warn("releasing snapshot caused exception", ex);
-                        }
-                    });
-
-                    final StepListener<ReplicationResponse> deleteRetentionLeaseStep = new StepListener<>();
-                    runUnderPrimaryPermit(() -> {
-                        try {
-                            // If the target previously had a copy of this shard then a file-based recovery might move its global
-                            // checkpoint backwards. We must therefore remove any existing retention lease so that we can create a
-                            // new one later on in the recovery.
-                            shard.removePeerRecoveryRetentionLease(
-                                request.targetNode().getId(),
-                                new ThreadedActionListener<>(
-                                    logger,
-                                    shard.getThreadPool(),
-                                    ThreadPool.Names.GENERIC,
-                                    deleteRetentionLeaseStep,
-                                    false
-                                )
-                            );
-                        } catch (RetentionLeaseNotFoundException e) {
-                            logger.debug("no peer-recovery retention lease for " + request.targetAllocationId());
-                            deleteRetentionLeaseStep.onResponse(null);
-                        }
-                    }, shardId + " removing retention lease for [" + request.targetAllocationId() + "]", shard, cancellableThreads, logger);
-
-                    deleteRetentionLeaseStep.whenComplete(ignored -> {
-                        assert Transports.assertNotTransportThread(RecoverySourceHandler.this + "[phase1]");
-                        phase1(wrappedSafeCommit.get(), startingSeqNo, () -> estimateNumOps, sendFileStep);
-                    }, onFailure);
-
-                } catch (final Exception e) {
-                    throw new RecoveryEngineException(shard.shardId(), 1, "sendFileStep failed", e);
-                }
+    protected void onSendFileStepComplete(
+        StepListener<SendFileResult> sendFileStep,
+        GatedCloseable<IndexCommit> wrappedSafeCommit,
+        Releasable releaseStore
+    ) {
+        sendFileStep.whenComplete(r -> {
+            logger.debug("sendFileStep completed");
+            IOUtils.close(wrappedSafeCommit, releaseStore);
+        }, e -> {
+            try {
+                IOUtils.close(wrappedSafeCommit, releaseStore);
+            } catch (final IOException ex) {
+                logger.warn("releasing snapshot caused exception", ex);
             }
-            assert startingSeqNo >= 0 : "startingSeqNo must be non negative. got: " + startingSeqNo;
-
-            sendFileStep.whenComplete(r -> {
-                assert Transports.assertNotTransportThread(RecoverySourceHandler.this + "[prepareTargetForTranslog]");
-                // For a sequence based recovery, the target can keep its local translog
-                prepareTargetForTranslog(countNumberOfHistoryOperations(startingSeqNo), prepareEngineStep);
-            }, onFailure);
-
-            prepareEngineStep.whenComplete(prepareEngineTime -> {
-                assert Transports.assertNotTransportThread(RecoverySourceHandler.this + "[phase2]");
-                /*
-                 * add shard to replication group (shard will receive replication requests from this point on) now that engine is open.
-                 * This means that any document indexed into the primary after this will be replicated to this replica as well
-                 * make sure to do this before sampling the max sequence number in the next step, to ensure that we send
-                 * all documents up to maxSeqNo in phase2.
-                 */
-                runUnderPrimaryPermit(
-                    () -> shard.initiateTracking(request.targetAllocationId()),
-                    shardId + " initiating tracking of " + request.targetAllocationId(),
-                    shard,
-                    cancellableThreads,
-                    logger
-                );
-
-                final long endingSeqNo = shard.seqNoStats().getMaxSeqNo();
-                if (logger.isTraceEnabled()) {
-                    logger.trace("snapshot translog for recovery; current size is [{}]", countNumberOfHistoryOperations(startingSeqNo));
-                }
-                final Translog.Snapshot phase2Snapshot = shard.newChangesSnapshot(
-                    PEER_RECOVERY_NAME,
-                    startingSeqNo,
-                    Long.MAX_VALUE,
-                    false,
-                    true
-                );
-                resources.add(phase2Snapshot);
-                retentionLock.close();
-
-                // we have to capture the max_seen_auto_id_timestamp and the max_seq_no_of_updates to make sure that these values
-                // are at least as high as the corresponding values on the primary when any of these operations were executed on it.
-                final long maxSeenAutoIdTimestamp = shard.getMaxSeenAutoIdTimestamp();
-                final long maxSeqNoOfUpdatesOrDeletes = shard.getMaxSeqNoOfUpdatesOrDeletes();
-                final RetentionLeases retentionLeases = shard.getRetentionLeases();
-                final long mappingVersionOnPrimary = shard.indexSettings().getIndexMetadata().getMappingVersion();
-                phase2(
-                    startingSeqNo,
-                    endingSeqNo,
-                    phase2Snapshot,
-                    maxSeenAutoIdTimestamp,
-                    maxSeqNoOfUpdatesOrDeletes,
-                    retentionLeases,
-                    mappingVersionOnPrimary,
-                    sendSnapshotStep
-                );
-
-            }, onFailure);
-
-            // Recovery target can trim all operations >= startingSeqNo as we have sent all these operations in the phase 2
-            final long trimAboveSeqNo = startingSeqNo - 1;
-            sendSnapshotStep.whenComplete(r -> finalizeRecovery(r.targetLocalCheckpoint, trimAboveSeqNo, finalizeStep), onFailure);
-
-            finalizeStep.whenComplete(r -> {
-                final long phase1ThrottlingWaitTime = 0L; // TODO: return the actual throttle time
-                final SendSnapshotResult sendSnapshotResult = sendSnapshotStep.result();
-                final SendFileResult sendFileResult = sendFileStep.result();
-                final RecoveryResponse response = new RecoveryResponse(
-                    sendFileResult.phase1FileNames,
-                    sendFileResult.phase1FileSizes,
-                    sendFileResult.phase1ExistingFileNames,
-                    sendFileResult.phase1ExistingFileSizes,
-                    sendFileResult.totalSize,
-                    sendFileResult.existingTotalSize,
-                    sendFileResult.took.millis(),
-                    phase1ThrottlingWaitTime,
-                    prepareEngineStep.result().millis(),
-                    sendSnapshotResult.sentOperations,
-                    sendSnapshotResult.tookTime.millis()
-                );
-                try {
-                    future.onResponse(response);
-                } finally {
-                    IOUtils.close(resources);
-                }
-            }, onFailure);
-        } catch (Exception e) {
-            IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
-        }
+        });
     }
 
-    private boolean isTargetSameHistory() {
+    protected boolean isTargetSameHistory() {
         final String targetHistoryUUID = request.metadataSnapshot().getHistoryUUID();
         assert targetHistoryUUID != null : "incoming target history missing";
         return targetHistoryUUID.equals(shard.getHistoryUUID());
@@ -411,62 +258,19 @@ private boolean isTargetSameHistory() {
 
     /**
      * Counts the number of history operations from the starting sequence number
-     * @param startingSeqNo   the starting sequence number to count; included
-     * @return                number of history operations
+     *
+     * @param startingSeqNo the starting sequence number to count; included
+     * @return number of history operations
      */
-    private int countNumberOfHistoryOperations(long startingSeqNo) throws IOException {
+    protected int countNumberOfHistoryOperations(long startingSeqNo) throws IOException {
         return shard.countNumberOfHistoryOperations(PEER_RECOVERY_NAME, startingSeqNo, Long.MAX_VALUE);
     }
 
-    static void runUnderPrimaryPermit(
-        CancellableThreads.Interruptible runnable,
-        String reason,
-        IndexShard primary,
-        CancellableThreads cancellableThreads,
-        Logger logger
-    ) {
-        cancellableThreads.execute(() -> {
-            CompletableFuture<Releasable> permit = new CompletableFuture<>();
-            final ActionListener<Releasable> onAcquired = new ActionListener<Releasable>() {
-                @Override
-                public void onResponse(Releasable releasable) {
-                    if (permit.complete(releasable) == false) {
-                        releasable.close();
-                    }
-                }
-
-                @Override
-                public void onFailure(Exception e) {
-                    permit.completeExceptionally(e);
-                }
-            };
-            primary.acquirePrimaryOperationPermit(onAcquired, ThreadPool.Names.SAME, reason);
-            try (Releasable ignored = FutureUtils.get(permit)) {
-                // check that the IndexShard still has the primary authority. This needs to be checked under operation permit to prevent
-                // races, as IndexShard will switch its authority only when it holds all operation permits, see IndexShard.relocated()
-                if (primary.isRelocatedPrimary()) {
-                    throw new IndexShardRelocatedException(primary.shardId());
-                }
-                runnable.run();
-            } finally {
-                // just in case we got an exception (likely interrupted) while waiting for the get
-                permit.whenComplete((r, e) -> {
-                    if (r != null) {
-                        r.close();
-                    }
-                    if (e != null) {
-                        logger.trace("suppressing exception on completion (it was already bubbled up or the operation was aborted)", e);
-                    }
-                });
-            }
-        });
-    }
-
     /**
      * Increases the store reference and returns a {@link Releasable} that will decrease the store reference using the generic thread pool.
      * We must never release the store using an interruptible thread as we can risk invalidating the node lock.
      */
-    private Releasable acquireStore(Store store) {
+    protected Releasable acquireStore(Store store) {
         store.incRef();
         return Releasables.releaseOnce(() -> runWithGenericThreadPool(store::decRef));
     }
@@ -476,7 +280,7 @@ private Releasable acquireStore(Store store) {
      * with the file systems due to interrupt (see {@link org.apache.lucene.store.NIOFSDirectory} javadocs for more detail).
      * This method acquires a safe commit and wraps it to make sure that it will be released using the generic thread pool.
      */
-    private GatedCloseable<IndexCommit> acquireSafeCommit(IndexShard shard) {
+    protected GatedCloseable<IndexCommit> acquireSafeCommit(IndexShard shard) {
         final GatedCloseable<IndexCommit> wrappedSafeCommit = shard.acquireSafeIndexCommit();
         final AtomicBoolean closed = new AtomicBoolean(false);
         return new GatedCloseable<>(wrappedSafeCommit.get(), () -> {
@@ -496,6 +300,11 @@ private void runWithGenericThreadPool(CheckedRunnable<Exception> task) {
         FutureUtils.get(future);
     }
 
+    /**
+     * A send file result
+     *
+     * @opensearch.internal
+     */
     static final class SendFileResult {
         final List<String> phase1FileNames;
         final List<Long> phase1FileSizes;
@@ -545,7 +354,13 @@ static final class SendFileResult {
      * segments that are missing. Only segments that have the same size and
      * checksum can be reused
      */
-    void phase1(IndexCommit snapshot, long startingSeqNo, IntSupplier translogOps, ActionListener<SendFileResult> listener) {
+    void phase1(
+        IndexCommit snapshot,
+        long startingSeqNo,
+        IntSupplier translogOps,
+        ActionListener<SendFileResult> listener,
+        boolean skipCreateRetentionLeaseStep
+    ) {
         cancellableThreads.checkForCancel();
         final Store store = shard.store();
         try {
@@ -638,12 +453,23 @@ void phase1(IndexCommit snapshot, long startingSeqNo, IntSupplier translogOps, A
                     sendFileInfoStep
                 );
 
-                sendFileInfoStep.whenComplete(
-                    r -> sendFiles(store, phase1Files.toArray(new StoreFileMetadata[0]), translogOps, sendFilesStep),
-                    listener::onFailure
-                );
+                sendFileInfoStep.whenComplete(r -> {
+                    logger.debug("sendFileInfoStep completed");
+                    sendFiles(store, phase1Files.toArray(new StoreFileMetadata[0]), translogOps, sendFilesStep);
+                }, listener::onFailure);
 
-                sendFilesStep.whenComplete(r -> createRetentionLease(startingSeqNo, createRetentionLeaseStep), listener::onFailure);
+                // When doing peer recovery of remote store enabled replica, retention leases are not required.
+                if (skipCreateRetentionLeaseStep) {
+                    sendFilesStep.whenComplete(r -> {
+                        logger.debug("sendFilesStep completed");
+                        createRetentionLeaseStep.onResponse(null);
+                    }, listener::onFailure);
+                } else {
+                    sendFilesStep.whenComplete(r -> {
+                        logger.debug("sendFilesStep completed");
+                        createRetentionLease(startingSeqNo, createRetentionLeaseStep);
+                    }, listener::onFailure);
+                }
 
                 createRetentionLeaseStep.whenComplete(retentionLease -> {
                     final long lastKnownGlobalCheckpoint = shard.getLastKnownGlobalCheckpoint();
@@ -659,6 +485,7 @@ void phase1(IndexCommit snapshot, long startingSeqNo, IntSupplier translogOps, A
                 final long totalSize = totalSizeInBytes;
                 final long existingTotalSize = existingTotalSizeInBytes;
                 cleanFilesStep.whenComplete(r -> {
+                    logger.debug("cleanFilesStep completed");
                     final TimeValue took = stopWatch.totalTime();
                     logger.trace("recovery [phase1]: took [{}]", took);
                     listener.onResponse(
@@ -701,8 +528,19 @@ void phase1(IndexCommit snapshot, long startingSeqNo, IntSupplier translogOps, A
         }
     }
 
+    void sendFiles(Store store, StoreFileMetadata[] files, IntSupplier translogOps, ActionListener<Void> listener) {
+        final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = transferHandler.createTransfer(
+            store,
+            files,
+            translogOps,
+            listener
+        );
+        resources.add(transfer);
+        transfer.start();
+    }
+
     void createRetentionLease(final long startingSeqNo, ActionListener<RetentionLease> listener) {
-        runUnderPrimaryPermit(() -> {
+        RunUnderPrimaryPermit.run(() -> {
             // Clone the peer recovery retention lease belonging to the source shard. We are retaining history between the the local
             // checkpoint of the safe commit we're creating and this lease's retained seqno with the retention lock, and by cloning an
             // existing lease we (approximately) know that all our peers are also retaining history as requested by the cloned lease. If
@@ -718,7 +556,10 @@ void createRetentionLease(final long startingSeqNo, ActionListener<RetentionLeas
                     new ThreadedActionListener<>(logger, shard.getThreadPool(), ThreadPool.Names.GENERIC, cloneRetentionLeaseStep, false)
                 );
                 logger.trace("cloned primary's retention lease as [{}]", clonedLease);
-                cloneRetentionLeaseStep.whenComplete(rr -> listener.onResponse(clonedLease), listener::onFailure);
+                cloneRetentionLeaseStep.whenComplete(rr -> {
+                    logger.debug("cloneRetentionLeaseStep completed");
+                    listener.onResponse(clonedLease);
+                }, listener::onFailure);
             } catch (RetentionLeaseNotFoundException e) {
                 // it's possible that the primary has no retention lease yet if we are doing a rolling upgrade from a version before
                 // 7.4, and in that case we just create a lease using the local checkpoint of the safe commit which we're using for
@@ -732,7 +573,10 @@ void createRetentionLease(final long startingSeqNo, ActionListener<RetentionLeas
                     estimatedGlobalCheckpoint,
                     new ThreadedActionListener<>(logger, shard.getThreadPool(), ThreadPool.Names.GENERIC, addRetentionLeaseStep, false)
                 );
-                addRetentionLeaseStep.whenComplete(rr -> listener.onResponse(newLease), listener::onFailure);
+                addRetentionLeaseStep.whenComplete(rr -> {
+                    logger.debug("addRetentionLeaseStep completed");
+                    listener.onResponse(newLease);
+                }, listener::onFailure);
                 logger.trace("created retention lease with estimated checkpoint of [{}]", estimatedGlobalCheckpoint);
             }
         }, shardId + " establishing retention lease for [" + request.targetAllocationId() + "]", shard, cancellableThreads, logger);
@@ -851,6 +695,11 @@ void phase2(
         sender.start();
     }
 
+    /**
+     * An operation chunk request
+     *
+     * @opensearch.internal
+     */
     private static class OperationChunkRequest implements MultiChunkTransfer.ChunkRequest {
         final List<Translog.Operation> operations;
         final boolean lastChunk;
@@ -971,7 +820,7 @@ void finalizeRecovery(long targetLocalCheckpoint, long trimAboveSeqNo, ActionLis
          * marking the shard as in-sync. If the relocation handoff holds all the permits then after the handoff completes and we acquire
          * the permit then the state of the shard will be relocated and this recovery will fail.
          */
-        runUnderPrimaryPermit(
+        RunUnderPrimaryPermit.run(
             () -> shard.markAllocationIdAsInSync(request.targetAllocationId(), targetLocalCheckpoint),
             shardId + " marking " + request.targetAllocationId() + " as in sync",
             shard,
@@ -983,7 +832,8 @@ void finalizeRecovery(long targetLocalCheckpoint, long trimAboveSeqNo, ActionLis
         cancellableThreads.checkForCancel();
         recoveryTarget.finalizeRecovery(globalCheckpoint, trimAboveSeqNo, finalizeListener);
         finalizeListener.whenComplete(r -> {
-            runUnderPrimaryPermit(
+            logger.debug("finalizeListenerStep completed");
+            RunUnderPrimaryPermit.run(
                 () -> shard.updateGlobalCheckpointForShard(request.targetAllocationId(), globalCheckpoint),
                 shardId + " updating " + request.targetAllocationId() + "'s global checkpoint",
                 shard,
@@ -993,20 +843,35 @@ void finalizeRecovery(long targetLocalCheckpoint, long trimAboveSeqNo, ActionLis
 
             if (request.isPrimaryRelocation()) {
                 logger.trace("performing relocation hand-off");
+                final Runnable forceSegRepRunnable = shard.indexSettings().isSegRepEnabled()
+                    ? recoveryTarget::forceSegmentFileSync
+                    : () -> {};
                 // TODO: make relocated async
                 // this acquires all IndexShard operation permits and will thus delay new recoveries until it is done
-                cancellableThreads.execute(() -> shard.relocated(request.targetAllocationId(), recoveryTarget::handoffPrimaryContext));
+                cancellableThreads.execute(
+                    () -> shard.relocated(request.targetAllocationId(), recoveryTarget::handoffPrimaryContext, forceSegRepRunnable)
+                );
                 /*
                  * if the recovery process fails after disabling primary mode on the source shard, both relocation source and
                  * target are failed (see {@link IndexShard#updateRoutingEntry}).
                  */
+            } else {
+                // Force round of segment replication to update its checkpoint to primary's
+                if (shard.indexSettings().isSegRepEnabled()) {
+                    cancellableThreads.execute(recoveryTarget::forceSegmentFileSync);
+                }
             }
             stopWatch.stop();
-            logger.trace("finalizing recovery took [{}]", stopWatch.totalTime());
+            logger.info("finalizing recovery took [{}]", stopWatch.totalTime());
             listener.onResponse(null);
         }, listener::onFailure);
     }
 
+    /**
+     * A result for a send snapshot
+     *
+     * @opensearch.internal
+     */
     static final class SendSnapshotResult {
         final long targetLocalCheckpoint;
         final int sentOperations;
@@ -1039,116 +904,6 @@ public String toString() {
             + '}';
     }
 
-    private static class FileChunk implements MultiChunkTransfer.ChunkRequest, Releasable {
-        final StoreFileMetadata md;
-        final BytesReference content;
-        final long position;
-        final boolean lastChunk;
-        final Releasable onClose;
-
-        FileChunk(StoreFileMetadata md, BytesReference content, long position, boolean lastChunk, Releasable onClose) {
-            this.md = md;
-            this.content = content;
-            this.position = position;
-            this.lastChunk = lastChunk;
-            this.onClose = onClose;
-        }
-
-        @Override
-        public boolean lastChunk() {
-            return lastChunk;
-        }
-
-        @Override
-        public void close() {
-            onClose.close();
-        }
-    }
-
-    void sendFiles(Store store, StoreFileMetadata[] files, IntSupplier translogOps, ActionListener<Void> listener) {
-        ArrayUtil.timSort(files, Comparator.comparingLong(StoreFileMetadata::length)); // send smallest first
-
-        final MultiChunkTransfer<StoreFileMetadata, FileChunk> multiFileSender = new MultiChunkTransfer<StoreFileMetadata, FileChunk>(
-            logger,
-            threadPool.getThreadContext(),
-            listener,
-            maxConcurrentFileChunks,
-            Arrays.asList(files)
-        ) {
-
-            final Deque<byte[]> buffers = new ConcurrentLinkedDeque<>();
-            InputStreamIndexInput currentInput = null;
-            long offset = 0;
-
-            @Override
-            protected void onNewResource(StoreFileMetadata md) throws IOException {
-                offset = 0;
-                IOUtils.close(currentInput, () -> currentInput = null);
-                final IndexInput indexInput = store.directory().openInput(md.name(), IOContext.READONCE);
-                currentInput = new InputStreamIndexInput(indexInput, md.length()) {
-                    @Override
-                    public void close() throws IOException {
-                        IOUtils.close(indexInput, super::close); // InputStreamIndexInput's close is a noop
-                    }
-                };
-            }
-
-            private byte[] acquireBuffer() {
-                final byte[] buffer = buffers.pollFirst();
-                if (buffer != null) {
-                    return buffer;
-                }
-                return new byte[chunkSizeInBytes];
-            }
-
-            @Override
-            protected FileChunk nextChunkRequest(StoreFileMetadata md) throws IOException {
-                assert Transports.assertNotTransportThread("read file chunk");
-                cancellableThreads.checkForCancel();
-                final byte[] buffer = acquireBuffer();
-                final int bytesRead = currentInput.read(buffer);
-                if (bytesRead == -1) {
-                    throw new CorruptIndexException("file truncated; length=" + md.length() + " offset=" + offset, md.name());
-                }
-                final boolean lastChunk = offset + bytesRead == md.length();
-                final FileChunk chunk = new FileChunk(
-                    md,
-                    new BytesArray(buffer, 0, bytesRead),
-                    offset,
-                    lastChunk,
-                    () -> buffers.addFirst(buffer)
-                );
-                offset += bytesRead;
-                return chunk;
-            }
-
-            @Override
-            protected void executeChunkRequest(FileChunk request, ActionListener<Void> listener) {
-                cancellableThreads.checkForCancel();
-                recoveryTarget.writeFileChunk(
-                    request.md,
-                    request.position,
-                    request.content,
-                    request.lastChunk,
-                    translogOps.getAsInt(),
-                    ActionListener.runBefore(listener, request::close)
-                );
-            }
-
-            @Override
-            protected void handleError(StoreFileMetadata md, Exception e) throws Exception {
-                handleErrorOnSendFiles(store, e, new StoreFileMetadata[] { md });
-            }
-
-            @Override
-            public void close() throws IOException {
-                IOUtils.close(currentInput, () -> currentInput = null);
-            }
-        };
-        resources.add(multiFileSender);
-        multiFileSender.start();
-    }
-
     private void cleanFiles(
         Store store,
         Store.MetadataSnapshot sourceMetadata,
@@ -1172,52 +927,9 @@ private void cleanFiles(
             ActionListener.delegateResponse(listener, (l, e) -> ActionListener.completeWith(l, () -> {
                 StoreFileMetadata[] mds = StreamSupport.stream(sourceMetadata.spliterator(), false).toArray(StoreFileMetadata[]::new);
                 ArrayUtil.timSort(mds, Comparator.comparingLong(StoreFileMetadata::length)); // check small files first
-                handleErrorOnSendFiles(store, e, mds);
+                transferHandler.handleErrorOnSendFiles(store, e, mds);
                 throw e;
             }))
         );
     }
-
-    private void handleErrorOnSendFiles(Store store, Exception e, StoreFileMetadata[] mds) throws Exception {
-        final IOException corruptIndexException = ExceptionsHelper.unwrapCorruption(e);
-        assert Transports.assertNotTransportThread(RecoverySourceHandler.this + "[handle error on send/clean files]");
-        if (corruptIndexException != null) {
-            Exception localException = null;
-            for (StoreFileMetadata md : mds) {
-                cancellableThreads.checkForCancel();
-                logger.debug("checking integrity for file {} after remove corruption exception", md);
-                if (store.checkIntegrityNoException(md) == false) { // we are corrupted on the primary -- fail!
-                    logger.warn("{} Corrupted file detected {} checksum mismatch", shardId, md);
-                    if (localException == null) {
-                        localException = corruptIndexException;
-                    }
-                    failEngine(corruptIndexException);
-                }
-            }
-            if (localException != null) {
-                throw localException;
-            } else { // corruption has happened on the way to replica
-                RemoteTransportException remoteException = new RemoteTransportException(
-                    "File corruption occurred on recovery but checksums are ok",
-                    null
-                );
-                remoteException.addSuppressed(e);
-                logger.warn(
-                    () -> new ParameterizedMessage(
-                        "{} Remote file corruption on node {}, recovering {}. local checksum OK",
-                        shardId,
-                        request.targetNode(),
-                        mds
-                    ),
-                    corruptIndexException
-                );
-                throw remoteException;
-            }
-        }
-        throw e;
-    }
-
-    protected void failEngine(IOException cause) {
-        shard.failShard("recovery", cause);
-    }
 }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandlerFactory.java b/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandlerFactory.java
new file mode 100644
index 0000000000000..ea13ca18bbfca
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoverySourceHandlerFactory.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.index.shard.IndexShard;
+
+/**
+ * Factory that supplies {@link RecoverySourceHandler}.
+ *
+ * @opensearch.internal
+ */
+public class RecoverySourceHandlerFactory {
+
+    public static RecoverySourceHandler create(
+        IndexShard shard,
+        RecoveryTargetHandler recoveryTarget,
+        StartRecoveryRequest request,
+        RecoverySettings recoverySettings
+    ) {
+        boolean isReplicaRecoveryWithRemoteTranslog = request.isPrimaryRelocation() == false && shard.isRemoteTranslogEnabled();
+        if (isReplicaRecoveryWithRemoteTranslog) {
+            return new RemoteStorePeerRecoverySourceHandler(
+                shard,
+                recoveryTarget,
+                shard.getThreadPool(),
+                request,
+                Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+                recoverySettings.getMaxConcurrentFileChunks(),
+                recoverySettings.getMaxConcurrentOperations()
+            );
+        } else {
+            return new LocalStorePeerRecoverySourceHandler(
+                shard,
+                recoveryTarget,
+                shard.getThreadPool(),
+                request,
+                Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+                recoverySettings.getMaxConcurrentFileChunks(),
+                recoverySettings.getMaxConcurrentOperations()
+            );
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryState.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryState.java
index d89d59e2f2c1b..cd6b1af709fb7 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryState.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryState.java
@@ -37,34 +37,33 @@
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.store.StoreStats;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationTimer;
 
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
 import java.util.Locale;
-import java.util.Map;
 
 /**
  * Keeps track of state related to shard recovery.
+ *
+ * @opensearch.internal
  */
-public class RecoveryState implements ToXContentFragment, Writeable {
+public class RecoveryState implements ReplicationState, ToXContentFragment, Writeable {
 
+    /**
+     * The stage of the recovery state
+     *
+     * @opensearch.internal
+     */
     public enum Stage {
         INIT((byte) 0),
 
@@ -119,10 +118,10 @@ public static Stage fromId(byte id) {
 
     private Stage stage;
 
-    private final Index index;
+    private final ReplicationLuceneIndex index;
     private final Translog translog;
     private final VerifyIndex verifyIndex;
-    private final Timer timer;
+    private final ReplicationTimer timer;
 
     private RecoverySource recoverySource;
     private ShardId shardId;
@@ -132,10 +131,15 @@ public static Stage fromId(byte id) {
     private boolean primary;
 
     public RecoveryState(ShardRouting shardRouting, DiscoveryNode targetNode, @Nullable DiscoveryNode sourceNode) {
-        this(shardRouting, targetNode, sourceNode, new Index());
+        this(shardRouting, targetNode, sourceNode, new ReplicationLuceneIndex());
     }
 
-    public RecoveryState(ShardRouting shardRouting, DiscoveryNode targetNode, @Nullable DiscoveryNode sourceNode, Index index) {
+    public RecoveryState(
+        ShardRouting shardRouting,
+        DiscoveryNode targetNode,
+        @Nullable DiscoveryNode sourceNode,
+        ReplicationLuceneIndex index
+    ) {
         assert shardRouting.initializing() : "only allow initializing shard routing to be recovered: " + shardRouting;
         RecoverySource recoverySource = shardRouting.recoverySource();
         assert (recoverySource.getType() == RecoverySource.Type.PEER) == (sourceNode != null)
@@ -149,18 +153,18 @@ public RecoveryState(ShardRouting shardRouting, DiscoveryNode targetNode, @Nulla
         this.index = index;
         translog = new Translog();
         verifyIndex = new VerifyIndex();
-        timer = new Timer();
+        timer = new ReplicationTimer();
         timer.start();
     }
 
     public RecoveryState(StreamInput in) throws IOException {
-        timer = new Timer(in);
+        timer = new ReplicationTimer(in);
         stage = Stage.fromId(in.readByte());
         shardId = new ShardId(in);
         recoverySource = RecoverySource.readFrom(in);
         targetNode = new DiscoveryNode(in);
         sourceNode = in.readOptionalWriteable(DiscoveryNode::new);
-        index = new Index(in);
+        index = new ReplicationLuceneIndex(in);
         translog = new Translog(in);
         verifyIndex = new VerifyIndex(in);
         primary = in.readBoolean();
@@ -244,7 +248,7 @@ public synchronized RecoveryState setStage(Stage stage) {
         return this;
     }
 
-    public Index getIndex() {
+    public ReplicationLuceneIndex getIndex() {
         return index;
     }
 
@@ -256,7 +260,8 @@ public Translog getTranslog() {
         return translog;
     }
 
-    public Timer getTimer() {
+    @Override
+    public ReplicationTimer getTimer() {
         return timer;
     }
 
@@ -280,10 +285,6 @@ public boolean getPrimary() {
         return primary;
     }
 
-    public static RecoveryState readRecoveryState(StreamInput in) throws IOException {
-        return new RecoveryState(in);
-    }
-
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
 
@@ -291,9 +292,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.field(Fields.TYPE, recoverySource.getType());
         builder.field(Fields.STAGE, stage.toString());
         builder.field(Fields.PRIMARY, primary);
-        builder.timeField(Fields.START_TIME_IN_MILLIS, Fields.START_TIME, timer.startTime);
-        if (timer.stopTime > 0) {
-            builder.timeField(Fields.STOP_TIME_IN_MILLIS, Fields.STOP_TIME, timer.stopTime);
+        builder.timeField(Fields.START_TIME_IN_MILLIS, Fields.START_TIME, timer.startTime());
+        if (timer.stopTime() > 0) {
+            builder.timeField(Fields.STOP_TIME_IN_MILLIS, Fields.STOP_TIME, timer.stopTime());
         }
         builder.humanReadableField(Fields.TOTAL_TIME_IN_MILLIS, Fields.TOTAL_TIME, new TimeValue(timer.time()));
 
@@ -334,6 +335,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Fields used in the recovery state
+     *
+     * @opensearch.internal
+     */
     static final class Fields {
         static final String ID = "id";
         static final String TYPE = "type";
@@ -356,97 +362,18 @@ static final class Fields {
         static final String TOTAL_ON_START = "total_on_start";
         static final String VERIFY_INDEX = "verify_index";
         static final String RECOVERED = "recovered";
-        static final String RECOVERED_IN_BYTES = "recovered_in_bytes";
         static final String CHECK_INDEX_TIME = "check_index_time";
         static final String CHECK_INDEX_TIME_IN_MILLIS = "check_index_time_in_millis";
-        static final String LENGTH = "length";
-        static final String LENGTH_IN_BYTES = "length_in_bytes";
-        static final String FILES = "files";
         static final String TOTAL = "total";
-        static final String TOTAL_IN_BYTES = "total_in_bytes";
-        static final String REUSED = "reused";
-        static final String REUSED_IN_BYTES = "reused_in_bytes";
         static final String PERCENT = "percent";
-        static final String DETAILS = "details";
-        static final String SIZE = "size";
-        static final String SOURCE_THROTTLE_TIME = "source_throttle_time";
-        static final String SOURCE_THROTTLE_TIME_IN_MILLIS = "source_throttle_time_in_millis";
-        static final String TARGET_THROTTLE_TIME = "target_throttle_time";
-        static final String TARGET_THROTTLE_TIME_IN_MILLIS = "target_throttle_time_in_millis";
-    }
-
-    public static class Timer implements Writeable {
-        protected long startTime = 0;
-        protected long startNanoTime = 0;
-        protected long time = -1;
-        protected long stopTime = 0;
-
-        public Timer() {}
-
-        public Timer(StreamInput in) throws IOException {
-            startTime = in.readVLong();
-            startNanoTime = in.readVLong();
-            stopTime = in.readVLong();
-            time = in.readVLong();
-        }
-
-        @Override
-        public synchronized void writeTo(StreamOutput out) throws IOException {
-            out.writeVLong(startTime);
-            out.writeVLong(startNanoTime);
-            out.writeVLong(stopTime);
-            // write a snapshot of current time, which is not per se the time field
-            out.writeVLong(time());
-        }
-
-        public synchronized void start() {
-            assert startTime == 0 : "already started";
-            startTime = System.currentTimeMillis();
-            startNanoTime = System.nanoTime();
-        }
-
-        /** Returns start time in millis */
-        public synchronized long startTime() {
-            return startTime;
-        }
-
-        /** Returns elapsed time in millis, or 0 if timer was not started */
-        public synchronized long time() {
-            if (startNanoTime == 0) {
-                return 0;
-            }
-            if (time >= 0) {
-                return time;
-            }
-            return Math.max(0, TimeValue.nsecToMSec(System.nanoTime() - startNanoTime));
-        }
-
-        /** Returns stop time in millis */
-        public synchronized long stopTime() {
-            return stopTime;
-        }
-
-        public synchronized void stop() {
-            assert stopTime == 0 : "already stopped";
-            stopTime = Math.max(System.currentTimeMillis(), startTime);
-            time = TimeValue.nsecToMSec(System.nanoTime() - startNanoTime);
-            assert time >= 0;
-        }
-
-        public synchronized void reset() {
-            startTime = 0;
-            startNanoTime = 0;
-            time = -1;
-            stopTime = 0;
-        }
-
-        // for tests
-        public long getStartNanoTime() {
-            return startNanoTime;
-        }
     }
 
-    public static class VerifyIndex extends Timer implements ToXContentFragment, Writeable {
+    /**
+     * Verifys the lucene index
+     *
+     * @opensearch.internal
+     */
+    public static class VerifyIndex extends ReplicationTimer implements ToXContentFragment, Writeable {
         private volatile long checkIndexTime;
 
         public VerifyIndex() {}
@@ -483,7 +410,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
-    public static class Translog extends Timer implements ToXContentFragment, Writeable {
+    /**
+     * The translog
+     *
+     * @opensearch.internal
+     */
+    public static class Translog extends ReplicationTimer implements ToXContentFragment, Writeable {
         public static final int UNKNOWN = -1;
 
         private int recovered;
@@ -628,466 +560,4 @@ public synchronized XContentBuilder toXContent(XContentBuilder builder, Params p
         }
     }
 
-    public static class FileDetail implements ToXContentObject, Writeable {
-        private String name;
-        private long length;
-        private long recovered;
-        private boolean reused;
-
-        public FileDetail(String name, long length, boolean reused) {
-            assert name != null;
-            this.name = name;
-            this.length = length;
-            this.reused = reused;
-        }
-
-        public FileDetail(StreamInput in) throws IOException {
-            name = in.readString();
-            length = in.readVLong();
-            recovered = in.readVLong();
-            reused = in.readBoolean();
-        }
-
-        @Override
-        public void writeTo(StreamOutput out) throws IOException {
-            out.writeString(name);
-            out.writeVLong(length);
-            out.writeVLong(recovered);
-            out.writeBoolean(reused);
-        }
-
-        void addRecoveredBytes(long bytes) {
-            assert reused == false : "file is marked as reused, can't update recovered bytes";
-            assert bytes >= 0 : "can't recovered negative bytes. got [" + bytes + "]";
-            recovered += bytes;
-        }
-
-        /**
-         * file name *
-         */
-        public String name() {
-            return name;
-        }
-
-        /**
-         * file length *
-         */
-        public long length() {
-            return length;
-        }
-
-        /**
-         * number of bytes recovered for this file (so far). 0 if the file is reused *
-         */
-        public long recovered() {
-            return recovered;
-        }
-
-        /**
-         * returns true if the file is reused from a local copy
-         */
-        public boolean reused() {
-            return reused;
-        }
-
-        boolean fullyRecovered() {
-            return reused == false && length == recovered;
-        }
-
-        @Override
-        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            builder.startObject();
-            builder.field(Fields.NAME, name);
-            builder.humanReadableField(Fields.LENGTH_IN_BYTES, Fields.LENGTH, new ByteSizeValue(length));
-            builder.field(Fields.REUSED, reused);
-            builder.humanReadableField(Fields.RECOVERED_IN_BYTES, Fields.RECOVERED, new ByteSizeValue(recovered));
-            builder.endObject();
-            return builder;
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            if (obj instanceof FileDetail) {
-                FileDetail other = (FileDetail) obj;
-                return name.equals(other.name) && length == other.length() && reused == other.reused() && recovered == other.recovered();
-            }
-            return false;
-        }
-
-        @Override
-        public int hashCode() {
-            int result = name.hashCode();
-            result = 31 * result + Long.hashCode(length);
-            result = 31 * result + Long.hashCode(recovered);
-            result = 31 * result + (reused ? 1 : 0);
-            return result;
-        }
-
-        @Override
-        public String toString() {
-            return "file (name [" + name + "], reused [" + reused + "], length [" + length + "], recovered [" + recovered + "])";
-        }
-    }
-
-    public static class RecoveryFilesDetails implements ToXContentFragment, Writeable {
-        protected final Map<String, FileDetail> fileDetails = new HashMap<>();
-        protected boolean complete;
-
-        public RecoveryFilesDetails() {}
-
-        RecoveryFilesDetails(StreamInput in) throws IOException {
-            int size = in.readVInt();
-            for (int i = 0; i < size; i++) {
-                FileDetail file = new FileDetail(in);
-                fileDetails.put(file.name, file);
-            }
-            if (in.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
-                complete = in.readBoolean();
-            } else {
-                // This flag is used by disk-based allocation to decide whether the remaining bytes measurement is accurate or not; if not
-                // then it falls back on an estimate. There's only a very short window in which the file details are present but incomplete
-                // so this is a reasonable approximation, and the stats reported to the disk-based allocator don't hit this code path
-                // anyway since they always use IndexShard#getRecoveryState which is never transported over the wire.
-                complete = fileDetails.isEmpty() == false;
-            }
-        }
-
-        @Override
-        public void writeTo(StreamOutput out) throws IOException {
-            final FileDetail[] files = values().toArray(new FileDetail[0]);
-            out.writeVInt(files.length);
-            for (FileDetail file : files) {
-                file.writeTo(out);
-            }
-            if (out.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
-                out.writeBoolean(complete);
-            }
-        }
-
-        @Override
-        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            if (params.paramAsBoolean("detailed", false)) {
-                builder.startArray(Fields.DETAILS);
-                for (FileDetail file : values()) {
-                    file.toXContent(builder, params);
-                }
-                builder.endArray();
-            }
-
-            return builder;
-        }
-
-        public void addFileDetails(String name, long length, boolean reused) {
-            assert complete == false : "addFileDetail for [" + name + "] when file details are already complete";
-            FileDetail existing = fileDetails.put(name, new FileDetail(name, length, reused));
-            assert existing == null : "file [" + name + "] is already reported";
-        }
-
-        public void addRecoveredBytesToFile(String name, long bytes) {
-            FileDetail file = fileDetails.get(name);
-            assert file != null : "file [" + name + "] hasn't been reported";
-            file.addRecoveredBytes(bytes);
-        }
-
-        public FileDetail get(String name) {
-            return fileDetails.get(name);
-        }
-
-        public void setComplete() {
-            complete = true;
-        }
-
-        public int size() {
-            return fileDetails.size();
-        }
-
-        public boolean isEmpty() {
-            return fileDetails.isEmpty();
-        }
-
-        public void clear() {
-            fileDetails.clear();
-            complete = false;
-        }
-
-        public Collection<FileDetail> values() {
-            return fileDetails.values();
-        }
-
-        public boolean isComplete() {
-            return complete;
-        }
-    }
-
-    public static class Index extends Timer implements ToXContentFragment, Writeable {
-        private final RecoveryFilesDetails fileDetails;
-
-        public static final long UNKNOWN = -1L;
-
-        private long sourceThrottlingInNanos = UNKNOWN;
-        private long targetThrottleTimeInNanos = UNKNOWN;
-
-        public Index() {
-            this(new RecoveryFilesDetails());
-        }
-
-        public Index(RecoveryFilesDetails recoveryFilesDetails) {
-            this.fileDetails = recoveryFilesDetails;
-        }
-
-        public Index(StreamInput in) throws IOException {
-            super(in);
-            fileDetails = new RecoveryFilesDetails(in);
-            sourceThrottlingInNanos = in.readLong();
-            targetThrottleTimeInNanos = in.readLong();
-        }
-
-        @Override
-        public synchronized void writeTo(StreamOutput out) throws IOException {
-            super.writeTo(out);
-            fileDetails.writeTo(out);
-            out.writeLong(sourceThrottlingInNanos);
-            out.writeLong(targetThrottleTimeInNanos);
-        }
-
-        public synchronized List<FileDetail> fileDetails() {
-            return Collections.unmodifiableList(new ArrayList<>(fileDetails.values()));
-        }
-
-        public synchronized void reset() {
-            super.reset();
-            fileDetails.clear();
-            sourceThrottlingInNanos = UNKNOWN;
-            targetThrottleTimeInNanos = UNKNOWN;
-        }
-
-        public synchronized void addFileDetail(String name, long length, boolean reused) {
-            fileDetails.addFileDetails(name, length, reused);
-        }
-
-        public synchronized void setFileDetailsComplete() {
-            fileDetails.setComplete();
-        }
-
-        public synchronized void addRecoveredBytesToFile(String name, long bytes) {
-            fileDetails.addRecoveredBytesToFile(name, bytes);
-        }
-
-        public synchronized void addSourceThrottling(long timeInNanos) {
-            if (sourceThrottlingInNanos == UNKNOWN) {
-                sourceThrottlingInNanos = timeInNanos;
-            } else {
-                sourceThrottlingInNanos += timeInNanos;
-            }
-        }
-
-        public synchronized void addTargetThrottling(long timeInNanos) {
-            if (targetThrottleTimeInNanos == UNKNOWN) {
-                targetThrottleTimeInNanos = timeInNanos;
-            } else {
-                targetThrottleTimeInNanos += timeInNanos;
-            }
-        }
-
-        public synchronized TimeValue sourceThrottling() {
-            return TimeValue.timeValueNanos(sourceThrottlingInNanos);
-        }
-
-        public synchronized TimeValue targetThrottling() {
-            return TimeValue.timeValueNanos(targetThrottleTimeInNanos);
-        }
-
-        /**
-         * total number of files that are part of this recovery, both re-used and recovered
-         */
-        public synchronized int totalFileCount() {
-            return fileDetails.size();
-        }
-
-        /**
-         * total number of files to be recovered (potentially not yet done)
-         */
-        public synchronized int totalRecoverFiles() {
-            int total = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused() == false) {
-                    total++;
-                }
-            }
-            return total;
-        }
-
-        /**
-         * number of file that were recovered (excluding on ongoing files)
-         */
-        public synchronized int recoveredFileCount() {
-            int count = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.fullyRecovered()) {
-                    count++;
-                }
-            }
-            return count;
-        }
-
-        /**
-         * percent of recovered (i.e., not reused) files out of the total files to be recovered
-         */
-        public synchronized float recoveredFilesPercent() {
-            int total = 0;
-            int recovered = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused() == false) {
-                    total++;
-                    if (file.fullyRecovered()) {
-                        recovered++;
-                    }
-                }
-            }
-            if (total == 0 && fileDetails.size() == 0) {      // indicates we are still in init phase
-                return 0.0f;
-            }
-            if (total == recovered) {
-                return 100.0f;
-            } else {
-                float result = 100.0f * (recovered / (float) total);
-                return result;
-            }
-        }
-
-        /**
-         * total number of bytes in th shard
-         */
-        public synchronized long totalBytes() {
-            long total = 0;
-            for (FileDetail file : fileDetails.values()) {
-                total += file.length();
-            }
-            return total;
-        }
-
-        /**
-         * total number of bytes recovered so far, including both existing and reused
-         */
-        public synchronized long recoveredBytes() {
-            long recovered = 0;
-            for (FileDetail file : fileDetails.values()) {
-                recovered += file.recovered();
-            }
-            return recovered;
-        }
-
-        /**
-         * total bytes of files to be recovered (potentially not yet done)
-         */
-        public synchronized long totalRecoverBytes() {
-            long total = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused() == false) {
-                    total += file.length();
-                }
-            }
-            return total;
-        }
-
-        /**
-         * @return number of bytes still to recover, i.e. {@link Index#totalRecoverBytes()} minus {@link Index#recoveredBytes()}, or
-         * {@code -1} if the full set of files to recover is not yet known
-         */
-        public synchronized long bytesStillToRecover() {
-            if (fileDetails.isComplete() == false) {
-                return -1L;
-            }
-            long total = 0L;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused() == false) {
-                    total += file.length() - file.recovered();
-                }
-            }
-            return total;
-        }
-
-        /**
-         * percent of bytes recovered out of total files bytes *to be* recovered
-         */
-        public synchronized float recoveredBytesPercent() {
-            long total = 0;
-            long recovered = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused() == false) {
-                    total += file.length();
-                    recovered += file.recovered();
-                }
-            }
-            if (total == 0 && fileDetails.size() == 0) {
-                // indicates we are still in init phase
-                return 0.0f;
-            }
-            if (total == recovered) {
-                return 100.0f;
-            } else {
-                return 100.0f * recovered / total;
-            }
-        }
-
-        public synchronized int reusedFileCount() {
-            int reused = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused()) {
-                    reused++;
-                }
-            }
-            return reused;
-        }
-
-        public synchronized long reusedBytes() {
-            long reused = 0;
-            for (FileDetail file : fileDetails.values()) {
-                if (file.reused()) {
-                    reused += file.length();
-                }
-            }
-            return reused;
-        }
-
-        @Override
-        public synchronized XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            // stream size first, as it matters more and the files section can be long
-            builder.startObject(Fields.SIZE);
-            builder.humanReadableField(Fields.TOTAL_IN_BYTES, Fields.TOTAL, new ByteSizeValue(totalBytes()));
-            builder.humanReadableField(Fields.REUSED_IN_BYTES, Fields.REUSED, new ByteSizeValue(reusedBytes()));
-            builder.humanReadableField(Fields.RECOVERED_IN_BYTES, Fields.RECOVERED, new ByteSizeValue(recoveredBytes()));
-            builder.field(Fields.PERCENT, String.format(Locale.ROOT, "%1.1f%%", recoveredBytesPercent()));
-            builder.endObject();
-
-            builder.startObject(Fields.FILES);
-            builder.field(Fields.TOTAL, totalFileCount());
-            builder.field(Fields.REUSED, reusedFileCount());
-            builder.field(Fields.RECOVERED, recoveredFileCount());
-            builder.field(Fields.PERCENT, String.format(Locale.ROOT, "%1.1f%%", recoveredFilesPercent()));
-            fileDetails.toXContent(builder, params);
-            builder.endObject();
-            builder.humanReadableField(Fields.TOTAL_TIME_IN_MILLIS, Fields.TOTAL_TIME, new TimeValue(time()));
-            builder.humanReadableField(Fields.SOURCE_THROTTLE_TIME_IN_MILLIS, Fields.SOURCE_THROTTLE_TIME, sourceThrottling());
-            builder.humanReadableField(Fields.TARGET_THROTTLE_TIME_IN_MILLIS, Fields.TARGET_THROTTLE_TIME, targetThrottling());
-            return builder;
-        }
-
-        @Override
-        public synchronized String toString() {
-            try {
-                XContentBuilder builder = XContentFactory.jsonBuilder().prettyPrint();
-                builder.startObject();
-                toXContent(builder, EMPTY_PARAMS);
-                builder.endObject();
-                return Strings.toString(builder);
-            } catch (IOException e) {
-                return "{ \"error\" : \"" + e.getMessage() + "\"}";
-            }
-        }
-
-        public synchronized FileDetail getFileDetails(String dest) {
-            return fileDetails.get(dest);
-        }
-    }
 }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTarget.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTarget.java
index 394b093059385..b7ae3a8f18cf4 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTarget.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTarget.java
@@ -32,22 +32,18 @@
 
 package org.opensearch.indices.recovery;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
 import org.apache.lucene.index.IndexFormatTooOldException;
-import org.opensearch.Assertions;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.util.CancellableThreads;
-import org.opensearch.common.util.concurrent.AbstractRefCounted;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.mapper.MapperException;
 import org.opensearch.index.seqno.ReplicationTracker;
@@ -56,45 +52,35 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardNotRecoveringException;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationTarget;
 
 import java.io.IOException;
+import java.nio.channels.FileChannel;
 import java.nio.file.Path;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicLong;
+
+import static org.opensearch.index.translog.Translog.TRANSLOG_UUID_KEY;
 
 /**
  * Represents a recovery where the current node is the target node of the recovery. To track recoveries in a central place, instances of
- * this class are created through {@link RecoveriesCollection}.
+ * this class are created through {@link ReplicationCollection}.
+ *
+ * @opensearch.internal
  */
-public class RecoveryTarget extends AbstractRefCounted implements RecoveryTargetHandler {
-
-    private final Logger logger;
-
-    private static final AtomicLong idGenerator = new AtomicLong();
+public class RecoveryTarget extends ReplicationTarget implements RecoveryTargetHandler {
 
     private static final String RECOVERY_PREFIX = "recovery.";
 
-    private final ShardId shardId;
-    private final long recoveryId;
-    private final IndexShard indexShard;
     private final DiscoveryNode sourceNode;
-    private final MultiFileWriter multiFileWriter;
-    private final RecoveryRequestTracker requestTracker = new RecoveryRequestTracker();
-    private final Store store;
-    private final PeerRecoveryTargetService.RecoveryListener listener;
-
-    private final AtomicBoolean finished = new AtomicBoolean();
-
-    private final CancellableThreads cancellableThreads;
-
-    // last time this status was accessed
-    private volatile long lastAccessTime = System.nanoTime();
+    protected final MultiFileWriter multiFileWriter;
 
     // latch that can be used to blockingly wait for RecoveryTarget to be closed
     private final CountDownLatch closedLatch = new CountDownLatch(1);
@@ -106,27 +92,12 @@ public class RecoveryTarget extends AbstractRefCounted implements RecoveryTarget
      * @param sourceNode                        source node of the recovery where we recover from
      * @param listener                          called when recovery is completed/failed
      */
-    public RecoveryTarget(IndexShard indexShard, DiscoveryNode sourceNode, PeerRecoveryTargetService.RecoveryListener listener) {
-        super("recovery_status");
-        this.cancellableThreads = new CancellableThreads();
-        this.recoveryId = idGenerator.incrementAndGet();
-        this.listener = listener;
-        this.logger = Loggers.getLogger(getClass(), indexShard.shardId());
-        this.indexShard = indexShard;
+    public RecoveryTarget(IndexShard indexShard, DiscoveryNode sourceNode, ReplicationListener listener) {
+        super("recovery_status", indexShard, indexShard.recoveryState().getIndex(), listener);
         this.sourceNode = sourceNode;
-        this.shardId = indexShard.shardId();
-        final String tempFilePrefix = RECOVERY_PREFIX + UUIDs.randomBase64UUID() + ".";
-        this.multiFileWriter = new MultiFileWriter(
-            indexShard.store(),
-            indexShard.recoveryState().getIndex(),
-            tempFilePrefix,
-            logger,
-            this::ensureRefCount
-        );
-        this.store = indexShard.store();
-        // make sure the store is not released until we are done.
-        store.incRef();
         indexShard.recoveryStats().incCurrentAsTarget();
+        final String tempFilePrefix = getPrefix() + UUIDs.randomBase64UUID() + ".";
+        this.multiFileWriter = new MultiFileWriter(indexShard.store(), stateIndex, tempFilePrefix, logger, this::ensureRefCount);
     }
 
     /**
@@ -138,21 +109,8 @@ public RecoveryTarget retryCopy() {
         return new RecoveryTarget(indexShard, sourceNode, listener);
     }
 
-    public ActionListener<Void> markRequestReceivedAndCreateListener(long requestSeqNo, ActionListener<Void> listener) {
-        return requestTracker.markReceivedAndCreateListener(requestSeqNo, listener);
-    }
-
-    public long recoveryId() {
-        return recoveryId;
-    }
-
-    public ShardId shardId() {
-        return shardId;
-    }
-
-    public IndexShard indexShard() {
-        ensureRefCount();
-        return indexShard;
+    public String source() {
+        return sourceNode.toString();
     }
 
     public DiscoveryNode sourceNode() {
@@ -167,29 +125,24 @@ public CancellableThreads cancellableThreads() {
         return cancellableThreads;
     }
 
-    /** return the last time this RecoveryStatus was used (based on System.nanoTime() */
-    public long lastAccessTime() {
-        return lastAccessTime;
-    }
-
-    /** sets the lasAccessTime flag to now */
-    public void setLastAccessTime() {
-        lastAccessTime = System.nanoTime();
+    public String description() {
+        return "recovery from " + source();
     }
 
-    public Store store() {
-        ensureRefCount();
-        return store;
+    @Override
+    public void notifyListener(ReplicationFailedException e, boolean sendShardFailure) {
+        listener.onFailure(state(), new RecoveryFailedException(state(), e.getMessage(), e), sendShardFailure);
     }
 
     /**
      * Closes the current recovery target and waits up to a certain timeout for resources to be freed.
      * Returns true if resetting the recovery was successful, false if the recovery target is already cancelled / failed or marked as done.
      */
-    boolean resetRecovery(CancellableThreads newTargetCancellableThreads) throws IOException {
+    public boolean reset(CancellableThreads newTargetCancellableThreads) throws IOException {
+        final long recoveryId = getId();
         if (finished.compareAndSet(false, true)) {
             try {
-                logger.debug("reset of recovery with shard {} and id [{}]", shardId, recoveryId);
+                logger.debug("reset of recovery with shard {} and id [{}]", shardId(), recoveryId);
             } finally {
                 // release the initial reference. recovery files will be cleaned as soon as ref count goes to zero, potentially now.
                 decRef();
@@ -199,7 +152,7 @@ boolean resetRecovery(CancellableThreads newTargetCancellableThreads) throws IOE
             } catch (CancellableThreads.ExecutionCancelledException e) {
                 logger.trace(
                     "new recovery target cancelled for shard {} while waiting on old recovery target with id [{}] to close",
-                    shardId,
+                    shardId(),
                     recoveryId
                 );
                 return false;
@@ -242,25 +195,10 @@ public void cancel(String reason) {
      * fail the recovery and call listener
      *
      * @param e                exception that encapsulating the failure
-     * @param sendShardFailure indicates whether to notify the master of the shard failure
+     * @param sendShardFailure indicates whether to notify the cluster-manager of the shard failure
      */
     public void fail(RecoveryFailedException e, boolean sendShardFailure) {
-        if (finished.compareAndSet(false, true)) {
-            try {
-                notifyListener(e, sendShardFailure);
-            } finally {
-                try {
-                    cancellableThreads.cancel("failed recovery [" + ExceptionsHelper.stackTrace(e) + "]");
-                } finally {
-                    // release the initial reference. recovery files will be cleaned as soon as ref count goes to zero, potentially now
-                    decRef();
-                }
-            }
-        }
-    }
-
-    public void notifyListener(RecoveryFailedException e, boolean sendShardFailure) {
-        listener.onRecoveryFailure(state(), e, sendShardFailure);
+        super.fail(e, sendShardFailure);
     }
 
     /** mark the current recovery as done */
@@ -275,7 +213,7 @@ public void markAsDone() {
                 // release the initial reference. recovery files will be cleaned as soon as ref count goes to zero, potentially now
                 decRef();
             }
-            listener.onRecoveryDone(state());
+            listener.onDone(state());
         }
     }
 
@@ -284,7 +222,6 @@ protected void closeInternal() {
         try {
             multiFileWriter.close();
         } finally {
-            // free store. increment happens in constructor
             store.decRef();
             indexShard.recoveryStats().decCurrentAsTarget();
             closedLatch.countDown();
@@ -293,15 +230,20 @@ protected void closeInternal() {
 
     @Override
     public String toString() {
-        return shardId + " [" + recoveryId + "]";
+        return shardId() + " [" + getId() + "]";
     }
 
-    private void ensureRefCount() {
-        if (refCount() <= 0) {
-            throw new OpenSearchException(
-                "RecoveryStatus is used but it's refcount is 0. Probably a mismatch between incRef/decRef " + "calls"
-            );
-        }
+    @Override
+    protected String getPrefix() {
+        return RECOVERY_PREFIX;
+    }
+
+    @Override
+    protected void onDone() {
+        assert multiFileWriter.tempFileNames.isEmpty() : "not all temporary files are renamed";
+        // this might still throw an exception ie. if the shard is CLOSED due to some other event.
+        // it's safer to decrement the reference in a try finally here.
+        indexShard.postRecovery("peer recovery done");
     }
 
     /*** Implementation of {@link RecoveryTargetHandler } */
@@ -316,6 +258,11 @@ public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Vo
         });
     }
 
+    @Override
+    public void forceSegmentFileSync() {
+        throw new UnsupportedOperationException("Method not supported on target!");
+    }
+
     @Override
     public void finalizeRecovery(final long globalCheckpoint, final long trimAboveSeqNo, ActionListener<Void> listener) {
         ActionListener.completeWith(listener, () -> {
@@ -371,7 +318,7 @@ public void indexTranslogOperations(
             translog.totalOperations(totalTranslogOps);
             assert indexShard().recoveryState() == state();
             if (indexShard().state() != IndexShardState.RECOVERING) {
-                throw new IndexShardNotRecoveringException(shardId, indexShard().state());
+                throw new IndexShardNotRecoveringException(shardId(), indexShard().state());
             }
             /*
              * The maxSeenAutoIdTimestampOnPrimary received from the primary is at least the highest auto_id_timestamp from any operation
@@ -423,7 +370,7 @@ public void receiveFileInfo(
         ActionListener.completeWith(listener, () -> {
             indexShard.resetRecoveryStage();
             indexShard.prepareForIndexRecovery();
-            final RecoveryState.Index index = state().getIndex();
+            final ReplicationLuceneIndex index = state().getIndex();
             for (int i = 0; i < phase1ExistingFileNames.size(); i++) {
                 index.addFileDetail(phase1ExistingFileNames.get(i), phase1ExistingFileSizes.get(i), true);
             }
@@ -454,13 +401,31 @@ public void cleanFiles(
             store.incRef();
             try {
                 store.cleanupAndVerify("recovery CleanFilesRequestHandler", sourceMetadata);
-                final String translogUUID = Translog.createEmptyTranslog(
-                    indexShard.shardPath().resolveTranslog(),
-                    globalCheckpoint,
-                    shardId,
-                    indexShard.getPendingPrimaryTerm()
-                );
-                store.associateIndexWithNewTranslog(translogUUID);
+
+                // Replicas for segment replication or remote snapshot indices do not create
+                // their own commit points and therefore do not modify the commit user data
+                // in their store. In these cases, reuse the primary's translog UUID.
+                final boolean reuseTranslogUUID = indexShard.indexSettings().isSegRepEnabled()
+                    || indexShard.indexSettings().isRemoteSnapshot();
+                if (reuseTranslogUUID) {
+                    final String translogUUID = store.getMetadata().getCommitUserData().get(TRANSLOG_UUID_KEY);
+                    Translog.createEmptyTranslog(
+                        indexShard.shardPath().resolveTranslog(),
+                        shardId(),
+                        globalCheckpoint,
+                        indexShard.getPendingPrimaryTerm(),
+                        translogUUID,
+                        FileChannel::open
+                    );
+                } else {
+                    final String translogUUID = Translog.createEmptyTranslog(
+                        indexShard.shardPath().resolveTranslog(),
+                        globalCheckpoint,
+                        shardId(),
+                        indexShard.getPendingPrimaryTerm()
+                    );
+                    store.associateIndexWithNewTranslog(translogUUID);
+                }
 
                 if (indexShard.getRetentionLeases().leases().isEmpty()) {
                     // if empty, may be a fresh IndexShard, so write an empty leases file to disk
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTargetHandler.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTargetHandler.java
index 1acef9a8592e4..ac28dabf815a5 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTargetHandler.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTargetHandler.java
@@ -31,17 +31,20 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.store.Store;
-import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.translog.Translog;
 
 import java.util.List;
 
-public interface RecoveryTargetHandler {
+/**
+ * Handler for the recovery target
+ *
+ * @opensearch.internal
+ */
+public interface RecoveryTargetHandler extends FileChunkWriter {
 
     /**
      * Prepares the target to receive translog operations, after all file have been copied
@@ -50,6 +53,14 @@ public interface RecoveryTargetHandler {
      */
     void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Void> listener);
 
+    /**
+     * Used with Segment replication only
+     *
+     * This function is used to force a sync target primary node with source (old primary). This is to avoid segment files
+     * conflict with replicas when target is promoted as primary.
+     */
+    void forceSegmentFileSync();
+
     /**
      * The finalize request refreshes the engine now that new segments are available, enables garbage collection of tombstone files, updates
      * the global checkpoint.
@@ -118,15 +129,5 @@ void receiveFileInfo(
      */
     void cleanFiles(int totalTranslogOps, long globalCheckpoint, Store.MetadataSnapshot sourceMetadata, ActionListener<Void> listener);
 
-    /** writes a partial file chunk to the target store */
-    void writeFileChunk(
-        StoreFileMetadata fileMetadata,
-        long position,
-        BytesReference content,
-        boolean lastChunk,
-        int totalTranslogOps,
-        ActionListener<Void> listener
-    );
-
     default void cancel() {}
 }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsRequest.java
index 94ac53f77a1d1..7fc3c08e8eef7 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsRequest.java
@@ -33,15 +33,20 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Request for recovery translog operations
+ *
+ * @opensearch.internal
+ */
 public class RecoveryTranslogOperationsRequest extends RecoveryTransportRequest {
 
     private final long recoveryId;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsResponse.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsResponse.java
index da2f224501816..9ea9f1d48a494 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsResponse.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTranslogOperationsResponse.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
+/**
+ * Response for recovery translog operations
+ *
+ * @opensearch.internal
+ */
 final class RecoveryTranslogOperationsResponse extends TransportResponse {
     final long localCheckpoint;
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTransportRequest.java b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTransportRequest.java
index 0ebc8c3d8550d..72fba90b5fe3b 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RecoveryTransportRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RecoveryTransportRequest.java
@@ -33,13 +33,18 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Transport request for recovery
+ *
+ * @opensearch.internal
+ */
 public abstract class RecoveryTransportRequest extends TransportRequest {
 
     private final long requestSeqNo;
diff --git a/server/src/main/java/org/opensearch/indices/recovery/ReestablishRecoveryRequest.java b/server/src/main/java/org/opensearch/indices/recovery/ReestablishRecoveryRequest.java
index bbf3f19ceb563..cdada2b458723 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/ReestablishRecoveryRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/ReestablishRecoveryRequest.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.indices.recovery;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
 /**
  * Represents a request for starting a peer recovery.
+ *
+ * @opensearch.internal
  */
 public class ReestablishRecoveryRequest extends TransportRequest {
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RemoteRecoveryTargetHandler.java b/server/src/main/java/org/opensearch/indices/recovery/RemoteRecoveryTargetHandler.java
index 35727baa83939..36beabc4a9026 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/RemoteRecoveryTargetHandler.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/RemoteRecoveryTargetHandler.java
@@ -34,63 +34,47 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.store.RateLimiter;
-import org.opensearch.LegacyESVersion;
-import org.opensearch.OpenSearchException;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionListenerResponseHandler;
-import org.opensearch.action.support.RetryableAction;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CancellableThreads;
-import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.indices.replication.RemoteSegmentFileChunkWriter;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
 import org.opensearch.transport.EmptyTransportResponseHandler;
-import org.opensearch.transport.RemoteTransportException;
-import org.opensearch.transport.SendRequestTransportException;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
-import java.io.IOException;
 import java.util.List;
-import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
 
+/**
+ * Target handler for remote recovery
+ *
+ * @opensearch.internal
+ */
 public class RemoteRecoveryTargetHandler implements RecoveryTargetHandler {
 
     private static final Logger logger = LogManager.getLogger(RemoteRecoveryTargetHandler.class);
 
     private final TransportService transportService;
-    private final ThreadPool threadPool;
     private final long recoveryId;
     private final ShardId shardId;
     private final DiscoveryNode targetNode;
     private final RecoverySettings recoverySettings;
-    private final Map<Object, RetryableAction<?>> onGoingRetryableActions = ConcurrentCollections.newConcurrentMap();
 
     private final TransportRequestOptions translogOpsRequestOptions;
-    private final TransportRequestOptions fileChunkRequestOptions;
 
-    private final AtomicLong bytesSinceLastPause = new AtomicLong();
     private final AtomicLong requestSeqNoGenerator = new AtomicLong(0);
-
-    private final Consumer<Long> onSourceThrottle;
-    private final boolean retriesSupported;
-    private volatile boolean isCancelled = false;
+    private final RetryableTransportClient retryableTransportClient;
+    private final RemoteSegmentFileChunkWriter fileChunkWriter;
 
     public RemoteRecoveryTargetHandler(
         long recoveryId,
@@ -101,21 +85,32 @@ public RemoteRecoveryTargetHandler(
         Consumer<Long> onSourceThrottle
     ) {
         this.transportService = transportService;
-        this.threadPool = transportService.getThreadPool();
+        // It is safe to pass the retry timeout value here because RemoteRecoveryTargetHandler
+        // created per recovery. Any change to RecoverySettings will be applied on the next
+        // recovery.
+        this.retryableTransportClient = new RetryableTransportClient(
+            transportService,
+            targetNode,
+            recoverySettings.internalActionRetryTimeout(),
+            logger
+        );
         this.recoveryId = recoveryId;
         this.shardId = shardId;
         this.targetNode = targetNode;
         this.recoverySettings = recoverySettings;
-        this.onSourceThrottle = onSourceThrottle;
         this.translogOpsRequestOptions = TransportRequestOptions.builder()
             .withType(TransportRequestOptions.Type.RECOVERY)
             .withTimeout(recoverySettings.internalActionLongTimeout())
             .build();
-        this.fileChunkRequestOptions = TransportRequestOptions.builder()
-            .withType(TransportRequestOptions.Type.RECOVERY)
-            .withTimeout(recoverySettings.internalActionTimeout())
-            .build();
-        this.retriesSupported = targetNode.getVersion().onOrAfter(LegacyESVersion.V_7_9_0);
+        this.fileChunkWriter = new RemoteSegmentFileChunkWriter(
+            recoveryId,
+            recoverySettings,
+            retryableTransportClient,
+            shardId,
+            PeerRecoveryTargetService.Actions.FILE_CHUNK,
+            requestSeqNoGenerator,
+            onSourceThrottle
+        );
     }
 
     public DiscoveryNode targetNode() {
@@ -132,12 +127,9 @@ public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Vo
             shardId,
             totalTranslogOps
         );
-        final TransportRequestOptions options = TransportRequestOptions.builder()
-            .withTimeout(recoverySettings.internalActionTimeout())
-            .build();
         final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
         final ActionListener<TransportResponse.Empty> responseListener = ActionListener.map(listener, r -> null);
-        executeRetryableAction(action, request, options, responseListener, reader);
+        retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
     }
 
     @Override
@@ -151,12 +143,9 @@ public void finalizeRecovery(final long globalCheckpoint, final long trimAboveSe
             globalCheckpoint,
             trimAboveSeqNo
         );
-        final TransportRequestOptions options = TransportRequestOptions.builder()
-            .withTimeout(recoverySettings.internalActionLongTimeout())
-            .build();
         final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
         final ActionListener<TransportResponse.Empty> responseListener = ActionListener.map(listener, r -> null);
-        executeRetryableAction(action, request, options, responseListener, reader);
+        retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
     }
 
     @Override
@@ -195,7 +184,25 @@ public void indexTranslogOperations(
         );
         final Writeable.Reader<RecoveryTranslogOperationsResponse> reader = RecoveryTranslogOperationsResponse::new;
         final ActionListener<RecoveryTranslogOperationsResponse> responseListener = ActionListener.map(listener, r -> r.localCheckpoint);
-        executeRetryableAction(action, request, translogOpsRequestOptions, responseListener, reader);
+        retryableTransportClient.executeRetryableAction(action, request, translogOpsRequestOptions, responseListener, reader);
+    }
+
+    /**
+     * Used with Segment replication only
+     *
+     * This function is used to force a sync target primary node with source (old primary). This is to avoid segment files
+     * conflict with replicas when target is promoted as primary.
+     */
+    @Override
+    public void forceSegmentFileSync() {
+        final long requestSeqNo = requestSeqNoGenerator.getAndIncrement();
+        transportService.submitRequest(
+            targetNode,
+            SegmentReplicationTargetService.Actions.FORCE_SYNC,
+            new ForceSyncRequest(requestSeqNo, recoveryId, shardId),
+            TransportRequestOptions.builder().withTimeout(recoverySettings.internalActionLongTimeout()).build(),
+            EmptyTransportResponseHandler.INSTANCE_SAME
+        ).txGet();
     }
 
     @Override
@@ -219,12 +226,9 @@ public void receiveFileInfo(
             phase1ExistingFileSizes,
             totalTranslogOps
         );
-        final TransportRequestOptions options = TransportRequestOptions.builder()
-            .withTimeout(recoverySettings.internalActionTimeout())
-            .build();
         final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
         final ActionListener<TransportResponse.Empty> responseListener = ActionListener.map(listener, r -> null);
-        executeRetryableAction(action, request, options, responseListener, reader);
+        retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
     }
 
     @Override
@@ -244,12 +248,14 @@ public void cleanFiles(
             totalTranslogOps,
             globalCheckpoint
         );
-        final TransportRequestOptions options = TransportRequestOptions.builder()
-            .withTimeout(recoverySettings.internalActionTimeout())
-            .build();
         final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
         final ActionListener<TransportResponse.Empty> responseListener = ActionListener.map(listener, r -> null);
-        executeRetryableAction(action, request, options, responseListener, reader);
+        retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
+    }
+
+    @Override
+    public void cancel() {
+        retryableTransportClient.cancel();
     }
 
     @Override
@@ -261,111 +267,6 @@ public void writeFileChunk(
         int totalTranslogOps,
         ActionListener<Void> listener
     ) {
-        // Pause using the rate limiter, if desired, to throttle the recovery
-        final long throttleTimeInNanos;
-        // always fetch the ratelimiter - it might be updated in real-time on the recovery settings
-        final RateLimiter rl = recoverySettings.rateLimiter();
-        if (rl != null) {
-            long bytes = bytesSinceLastPause.addAndGet(content.length());
-            if (bytes > rl.getMinPauseCheckBytes()) {
-                // Time to pause
-                bytesSinceLastPause.addAndGet(-bytes);
-                try {
-                    throttleTimeInNanos = rl.pause(bytes);
-                    onSourceThrottle.accept(throttleTimeInNanos);
-                } catch (IOException e) {
-                    throw new OpenSearchException("failed to pause recovery", e);
-                }
-            } else {
-                throttleTimeInNanos = 0;
-            }
-        } else {
-            throttleTimeInNanos = 0;
-        }
-
-        final String action = PeerRecoveryTargetService.Actions.FILE_CHUNK;
-        final long requestSeqNo = requestSeqNoGenerator.getAndIncrement();
-        /* we send estimateTotalOperations with every request since we collect stats on the target and that way we can
-         * see how many translog ops we accumulate while copying files across the network. A future optimization
-         * would be in to restart file copy again (new deltas) if we have too many translog ops are piling up.
-         */
-        final RecoveryFileChunkRequest request = new RecoveryFileChunkRequest(
-            recoveryId,
-            requestSeqNo,
-            shardId,
-            fileMetadata,
-            position,
-            content,
-            lastChunk,
-            totalTranslogOps,
-            throttleTimeInNanos
-        );
-        final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
-        executeRetryableAction(action, request, fileChunkRequestOptions, ActionListener.map(listener, r -> null), reader);
-    }
-
-    @Override
-    public void cancel() {
-        isCancelled = true;
-        if (onGoingRetryableActions.isEmpty()) {
-            return;
-        }
-        final RuntimeException exception = new CancellableThreads.ExecutionCancelledException("recovery was cancelled");
-        // Dispatch to generic as cancellation calls can come on the cluster state applier thread
-        threadPool.generic().execute(() -> {
-            for (RetryableAction<?> action : onGoingRetryableActions.values()) {
-                action.cancel(exception);
-            }
-            onGoingRetryableActions.clear();
-        });
-    }
-
-    private <T extends TransportResponse> void executeRetryableAction(
-        String action,
-        RecoveryTransportRequest request,
-        TransportRequestOptions options,
-        ActionListener<T> actionListener,
-        Writeable.Reader<T> reader
-    ) {
-        final Object key = new Object();
-        final ActionListener<T> removeListener = ActionListener.runBefore(actionListener, () -> onGoingRetryableActions.remove(key));
-        final TimeValue initialDelay = TimeValue.timeValueMillis(200);
-        final TimeValue timeout = recoverySettings.internalActionRetryTimeout();
-        final RetryableAction<T> retryableAction = new RetryableAction<T>(logger, threadPool, initialDelay, timeout, removeListener) {
-
-            @Override
-            public void tryAction(ActionListener<T> listener) {
-                transportService.sendRequest(
-                    targetNode,
-                    action,
-                    request,
-                    options,
-                    new ActionListenerResponseHandler<>(listener, reader, ThreadPool.Names.GENERIC)
-                );
-            }
-
-            @Override
-            public boolean shouldRetry(Exception e) {
-                return retriesSupported && retryableException(e);
-            }
-        };
-        onGoingRetryableActions.put(key, retryableAction);
-        retryableAction.run();
-        if (isCancelled) {
-            retryableAction.cancel(new CancellableThreads.ExecutionCancelledException("recovery was cancelled"));
-        }
-    }
-
-    private static boolean retryableException(Exception e) {
-        if (e instanceof ConnectTransportException) {
-            return true;
-        } else if (e instanceof SendRequestTransportException) {
-            final Throwable cause = ExceptionsHelper.unwrapCause(e);
-            return cause instanceof ConnectTransportException;
-        } else if (e instanceof RemoteTransportException) {
-            final Throwable cause = ExceptionsHelper.unwrapCause(e);
-            return cause instanceof CircuitBreakingException || cause instanceof OpenSearchRejectedExecutionException;
-        }
-        return false;
+        fileChunkWriter.writeFileChunk(fileMetadata, position, content, lastChunk, totalTranslogOps, listener);
     }
 }
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandler.java b/server/src/main/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandler.java
new file mode 100644
index 0000000000000..66c7a3b48f28f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandler.java
@@ -0,0 +1,105 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.apache.lucene.index.IndexCommit;
+import org.opensearch.action.StepListener;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.engine.RecoveryEngineException;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.RunUnderPrimaryPermit;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transports;
+
+import java.io.IOException;
+import java.util.function.Consumer;
+
+/**
+ * This handler is used when peer recovery target is a remote store enabled replica.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStorePeerRecoverySourceHandler extends RecoverySourceHandler {
+
+    public RemoteStorePeerRecoverySourceHandler(
+        IndexShard shard,
+        RecoveryTargetHandler recoveryTarget,
+        ThreadPool threadPool,
+        StartRecoveryRequest request,
+        int fileChunkSizeInBytes,
+        int maxConcurrentFileChunks,
+        int maxConcurrentOperations
+    ) {
+        super(shard, recoveryTarget, threadPool, request, fileChunkSizeInBytes, maxConcurrentFileChunks, maxConcurrentOperations);
+    }
+
+    @Override
+    protected void innerRecoveryToTarget(ActionListener<RecoveryResponse> listener, Consumer<Exception> onFailure) throws IOException {
+        // A replica of an index with remote translog does not require the translogs locally and keeps receiving the
+        // updated segments file on refresh, flushes, and merges. In recovery, here, only file-based recovery is performed
+        // and there is no translog replay done.
+
+        final StepListener<SendFileResult> sendFileStep = new StepListener<>();
+        final StepListener<TimeValue> prepareEngineStep = new StepListener<>();
+        final StepListener<SendSnapshotResult> sendSnapshotStep = new StepListener<>();
+
+        // It is always file based recovery while recovering replicas which are not relocating primary where the
+        // underlying indices are backed by remote store for storing segments and translog
+
+        final GatedCloseable<IndexCommit> wrappedSafeCommit;
+        try {
+            wrappedSafeCommit = acquireSafeCommit(shard);
+            resources.add(wrappedSafeCommit);
+        } catch (final Exception e) {
+            throw new RecoveryEngineException(shard.shardId(), 1, "snapshot failed", e);
+        }
+
+        final long startingSeqNo = Long.parseLong(wrappedSafeCommit.get().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)) + 1L;
+        logger.trace("performing file-based recovery followed by history replay starting at [{}]", startingSeqNo);
+
+        try {
+            final Releasable releaseStore = acquireStore(shard.store());
+            resources.add(releaseStore);
+            onSendFileStepComplete(sendFileStep, wrappedSafeCommit, releaseStore);
+
+            assert Transports.assertNotTransportThread(this + "[phase1]");
+            phase1(wrappedSafeCommit.get(), startingSeqNo, () -> 0, sendFileStep, true);
+        } catch (final Exception e) {
+            throw new RecoveryEngineException(shard.shardId(), 1, "sendFileStep failed", e);
+        }
+        assert startingSeqNo >= 0 : "startingSeqNo must be non negative. got: " + startingSeqNo;
+
+        sendFileStep.whenComplete(r -> {
+            logger.debug("sendFileStep completed");
+            assert Transports.assertNotTransportThread(this + "[prepareTargetForTranslog]");
+            // For a sequence based recovery, the target can keep its local translog
+            prepareTargetForTranslog(0, prepareEngineStep);
+        }, onFailure);
+
+        prepareEngineStep.whenComplete(prepareEngineTime -> {
+            logger.debug("prepareEngineStep completed");
+            assert Transports.assertNotTransportThread(this + "[phase2]");
+            RunUnderPrimaryPermit.run(
+                () -> shard.initiateTracking(request.targetAllocationId()),
+                shardId + " initiating tracking of " + request.targetAllocationId(),
+                shard,
+                cancellableThreads,
+                logger
+            );
+            final long endingSeqNo = shard.seqNoStats().getMaxSeqNo();
+            sendSnapshotStep.onResponse(new SendSnapshotResult(endingSeqNo, 0, TimeValue.ZERO));
+        }, onFailure);
+
+        finalizeStepAndCompleteFuture(startingSeqNo, sendSnapshotStep, sendFileStep, prepareEngineStep, onFailure);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/RetryableTransportClient.java b/server/src/main/java/org/opensearch/indices/recovery/RetryableTransportClient.java
new file mode 100644
index 0000000000000..42317d10cc530
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/RetryableTransportClient.java
@@ -0,0 +1,139 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.LegacyESVersion;
+import org.opensearch.action.ActionListenerResponseHandler;
+import org.opensearch.action.support.RetryableAction;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.transport.RemoteTransportException;
+import org.opensearch.transport.SendRequestTransportException;
+import org.opensearch.transport.TransportRequest;
+import org.opensearch.transport.TransportRequestOptions;
+import org.opensearch.transport.TransportService;
+
+import java.util.Map;
+
+/**
+ * Client that implements retry functionality for transport layer requests.
+ *
+ * @opensearch.internal
+ */
+public final class RetryableTransportClient {
+
+    private final ThreadPool threadPool;
+    private final Map<Object, RetryableAction<?>> onGoingRetryableActions = ConcurrentCollections.newConcurrentMap();
+    private volatile boolean isCancelled = false;
+    private final TransportService transportService;
+    private final TimeValue retryTimeout;
+    private final DiscoveryNode targetNode;
+
+    private final Logger logger;
+
+    public RetryableTransportClient(TransportService transportService, DiscoveryNode targetNode, TimeValue retryTimeout, Logger logger) {
+        this.threadPool = transportService.getThreadPool();
+        this.transportService = transportService;
+        this.retryTimeout = retryTimeout;
+        this.targetNode = targetNode;
+        this.logger = logger;
+    }
+
+    /**
+     * Execute a retryable action.
+     * @param action {@link String} Action Name.
+     * @param request {@link TransportRequest} Transport request to execute.
+     * @param actionListener {@link ActionListener} Listener to complete
+     * @param reader {@link Writeable.Reader} Reader to read the response stream.
+     * @param <T> {@link TransportResponse} type.
+     */
+    public <T extends TransportResponse> void executeRetryableAction(
+        String action,
+        TransportRequest request,
+        ActionListener<T> actionListener,
+        Writeable.Reader<T> reader
+    ) {
+        final TransportRequestOptions options = TransportRequestOptions.builder().withTimeout(retryTimeout).build();
+        executeRetryableAction(action, request, options, actionListener, reader);
+    }
+
+    public <T extends TransportResponse> void executeRetryableAction(
+        String action,
+        TransportRequest request,
+        TransportRequestOptions options,
+        ActionListener<T> actionListener,
+        Writeable.Reader<T> reader
+    ) {
+        final Object key = new Object();
+        final ActionListener<T> removeListener = ActionListener.runBefore(actionListener, () -> onGoingRetryableActions.remove(key));
+        final TimeValue initialDelay = TimeValue.timeValueMillis(200);
+        final RetryableAction<T> retryableAction = new RetryableAction<T>(logger, threadPool, initialDelay, retryTimeout, removeListener) {
+
+            @Override
+            public void tryAction(ActionListener<T> listener) {
+                transportService.sendRequest(
+                    targetNode,
+                    action,
+                    request,
+                    options,
+                    new ActionListenerResponseHandler<>(listener, reader, ThreadPool.Names.GENERIC)
+                );
+            }
+
+            @Override
+            public boolean shouldRetry(Exception e) {
+                return targetNode.getVersion().onOrAfter(LegacyESVersion.V_7_9_0) && retryableException(e);
+            }
+        };
+        onGoingRetryableActions.put(key, retryableAction);
+        retryableAction.run();
+        if (isCancelled) {
+            retryableAction.cancel(new CancellableThreads.ExecutionCancelledException("retryable action was cancelled"));
+        }
+    }
+
+    public void cancel() {
+        isCancelled = true;
+        if (onGoingRetryableActions.isEmpty()) {
+            return;
+        }
+        final RuntimeException exception = new CancellableThreads.ExecutionCancelledException("retryable action was cancelled");
+        // Dispatch to generic as cancellation calls can come on the cluster state applier thread
+        threadPool.generic().execute(() -> {
+            for (RetryableAction<?> action : onGoingRetryableActions.values()) {
+                action.cancel(exception);
+            }
+            onGoingRetryableActions.clear();
+        });
+    }
+
+    private static boolean retryableException(Exception e) {
+        if (e instanceof ConnectTransportException) {
+            return true;
+        } else if (e instanceof SendRequestTransportException) {
+            final Throwable cause = ExceptionsHelper.unwrapCause(e);
+            return cause instanceof ConnectTransportException;
+        } else if (e instanceof RemoteTransportException) {
+            final Throwable cause = ExceptionsHelper.unwrapCause(e);
+            return cause instanceof CircuitBreakingException || cause instanceof OpenSearchRejectedExecutionException;
+        }
+        return false;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/recovery/StartRecoveryRequest.java b/server/src/main/java/org/opensearch/indices/recovery/StartRecoveryRequest.java
index f2efae2fbe798..91802448abcae 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/StartRecoveryRequest.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/StartRecoveryRequest.java
@@ -33,10 +33,10 @@
 package org.opensearch.indices.recovery;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.transport.TransportRequest;
 
@@ -44,6 +44,8 @@
 
 /**
  * Represents a request for starting a peer recovery.
+ *
+ * @opensearch.internal
  */
 public class StartRecoveryRequest extends TransportRequest {
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/package-info.java b/server/src/main/java/org/opensearch/indices/recovery/package-info.java
new file mode 100644
index 0000000000000..3c850b2a84122
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/recovery/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Peer Recovery Package. */
+package org.opensearch.indices.recovery;
diff --git a/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoRequest.java b/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoRequest.java
new file mode 100644
index 0000000000000..6120b5302eb35
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoRequest.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.SegmentReplicationTransportRequest;
+
+import java.io.IOException;
+
+/**
+ * Request object for fetching segment metadata for a {@link ReplicationCheckpoint} from
+ * a {@link SegmentReplicationSource}. This object is created by the target node and sent
+ * to the source node.
+ *
+ * @opensearch.internal
+ */
+public class CheckpointInfoRequest extends SegmentReplicationTransportRequest {
+
+    private final ReplicationCheckpoint checkpoint;
+
+    public CheckpointInfoRequest(StreamInput in) throws IOException {
+        super(in);
+        checkpoint = new ReplicationCheckpoint(in);
+    }
+
+    public CheckpointInfoRequest(
+        long replicationId,
+        String targetAllocationId,
+        DiscoveryNode targetNode,
+        ReplicationCheckpoint checkpoint
+    ) {
+        super(replicationId, targetAllocationId, targetNode);
+        this.checkpoint = checkpoint;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        checkpoint.writeTo(out);
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return checkpoint;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoResponse.java b/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoResponse.java
new file mode 100644
index 0000000000000..9fd3b7f3afb80
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/CheckpointInfoResponse.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Response returned from a {@link SegmentReplicationSource} that includes the file metadata, and SegmentInfos
+ * associated with a particular {@link ReplicationCheckpoint}. The {@link SegmentReplicationSource} may determine that
+ * the requested {@link ReplicationCheckpoint} is behind and return a different {@link ReplicationCheckpoint} in this response.
+ *
+ * @opensearch.internal
+ */
+public class CheckpointInfoResponse extends TransportResponse {
+
+    private final ReplicationCheckpoint checkpoint;
+    private final Map<String, StoreFileMetadata> metadataMap;
+    private final byte[] infosBytes;
+
+    public CheckpointInfoResponse(
+        final ReplicationCheckpoint checkpoint,
+        final Map<String, StoreFileMetadata> metadataMap,
+        final byte[] infosBytes
+    ) {
+        this.checkpoint = checkpoint;
+        this.metadataMap = metadataMap;
+        this.infosBytes = infosBytes;
+    }
+
+    public CheckpointInfoResponse(StreamInput in) throws IOException {
+        this.checkpoint = new ReplicationCheckpoint(in);
+        this.metadataMap = in.readMap(StreamInput::readString, StoreFileMetadata::new);
+        this.infosBytes = in.readByteArray();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        checkpoint.writeTo(out);
+        out.writeMap(metadataMap, StreamOutput::writeString, (valueOut, fc) -> fc.writeTo(valueOut));
+        out.writeByteArray(infosBytes);
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return checkpoint;
+    }
+
+    public Map<String, StoreFileMetadata> getMetadataMap() {
+        return metadataMap;
+    }
+
+    public byte[] getInfosBytes() {
+        return infosBytes;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesRequest.java b/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesRequest.java
new file mode 100644
index 0000000000000..9fd90837cb1a5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesRequest.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.SegmentReplicationTransportRequest;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * Request object for fetching a list of segment files metadata from a {@link SegmentReplicationSource}.
+ * This object is created by the target node and sent to the source node.
+ *
+ * @opensearch.internal
+ */
+public class GetSegmentFilesRequest extends SegmentReplicationTransportRequest {
+
+    private final List<StoreFileMetadata> filesToFetch;
+    private final ReplicationCheckpoint checkpoint;
+
+    public GetSegmentFilesRequest(StreamInput in) throws IOException {
+        super(in);
+        this.filesToFetch = in.readList(StoreFileMetadata::new);
+        this.checkpoint = new ReplicationCheckpoint(in);
+    }
+
+    public GetSegmentFilesRequest(
+        long replicationId,
+        String targetAllocationId,
+        DiscoveryNode targetNode,
+        List<StoreFileMetadata> filesToFetch,
+        ReplicationCheckpoint checkpoint
+    ) {
+        super(replicationId, targetAllocationId, targetNode);
+        this.filesToFetch = filesToFetch;
+        this.checkpoint = checkpoint;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeList(filesToFetch);
+        checkpoint.writeTo(out);
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return checkpoint;
+    }
+
+    public List<StoreFileMetadata> getFilesToFetch() {
+        return filesToFetch;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesResponse.java b/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesResponse.java
new file mode 100644
index 0000000000000..234c053b27b25
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/GetSegmentFilesResponse.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.store.StoreFileMetadata;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * Response from a {@link SegmentReplicationSource} indicating that a replication event has completed.
+ *
+ * @opensearch.internal
+ */
+public class GetSegmentFilesResponse extends TransportResponse {
+
+    List<StoreFileMetadata> files;
+
+    public GetSegmentFilesResponse(List<StoreFileMetadata> files) {
+        this.files = files;
+    }
+
+    public GetSegmentFilesResponse(StreamInput out) throws IOException {
+        out.readList(StoreFileMetadata::new);
+    }
+
+    public List<StoreFileMetadata> getFiles() {
+        return files;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeCollection(files);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/OngoingSegmentReplications.java b/server/src/main/java/org/opensearch/indices/replication/OngoingSegmentReplications.java
new file mode 100644
index 0000000000000..268894b1c0af3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/OngoingSegmentReplications.java
@@ -0,0 +1,294 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.OpenSearchException;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.CopyState;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+/**
+ * Manages references to ongoing segrep events on a node.
+ * Each replica will have a new {@link SegmentReplicationSourceHandler} created when starting replication.
+ * CopyStates will be cached for reuse between replicas and only released when all replicas have finished copying segments.
+ *
+ * @opensearch.internal
+ */
+class OngoingSegmentReplications {
+
+    private static final Logger logger = LogManager.getLogger(OngoingSegmentReplications.class);
+    private final RecoverySettings recoverySettings;
+    private final IndicesService indicesService;
+    private final Map<ReplicationCheckpoint, CopyState> copyStateMap;
+    private final Map<String, SegmentReplicationSourceHandler> allocationIdToHandlers;
+
+    /**
+     * Constructor.
+     *
+     * @param indicesService   {@link IndicesService}
+     * @param recoverySettings {@link RecoverySettings}
+     */
+    OngoingSegmentReplications(IndicesService indicesService, RecoverySettings recoverySettings) {
+        this.indicesService = indicesService;
+        this.recoverySettings = recoverySettings;
+        this.copyStateMap = Collections.synchronizedMap(new HashMap<>());
+        this.allocationIdToHandlers = ConcurrentCollections.newConcurrentMap();
+    }
+
+    /**
+     * Operations on the {@link #copyStateMap} member.
+     */
+
+    /**
+     * A synchronized method that checks {@link #copyStateMap} for the given {@link ReplicationCheckpoint} key
+     * and returns the cached value if one is present. If the key is not present, a {@link CopyState}
+     * object is constructed and stored in the map before being returned.
+     */
+    synchronized CopyState getCachedCopyState(ReplicationCheckpoint checkpoint) throws IOException {
+        if (isInCopyStateMap(checkpoint)) {
+            final CopyState copyState = fetchFromCopyStateMap(checkpoint);
+            // we incref the copyState for every replica that is using this checkpoint.
+            // decref will happen when copy completes.
+            copyState.incRef();
+            return copyState;
+        } else {
+            // From the checkpoint's shard ID, fetch the IndexShard
+            ShardId shardId = checkpoint.getShardId();
+            final IndexService indexService = indicesService.indexServiceSafe(shardId.getIndex());
+            final IndexShard indexShard = indexService.getShard(shardId.id());
+            // build the CopyState object and cache it before returning
+            final CopyState copyState = new CopyState(checkpoint, indexShard);
+
+            /**
+             * Use the checkpoint from the request as the key in the map, rather than
+             * the checkpoint from the created CopyState. This maximizes cache hits
+             * if replication targets make a request with an older checkpoint.
+             * Replication targets are expected to fetch the checkpoint in the response
+             * CopyState to bring themselves up to date.
+             */
+            addToCopyStateMap(checkpoint, copyState);
+            return copyState;
+        }
+    }
+
+    /**
+     * Start sending files to the replica.
+     *
+     * @param request  {@link GetSegmentFilesRequest}
+     * @param listener {@link ActionListener} that resolves when sending files is complete.
+     */
+    void startSegmentCopy(GetSegmentFilesRequest request, ActionListener<GetSegmentFilesResponse> listener) {
+        final SegmentReplicationSourceHandler handler = allocationIdToHandlers.get(request.getTargetAllocationId());
+        if (handler != null) {
+            if (handler.isReplicating()) {
+                throw new OpenSearchException(
+                    "Replication to shard {}, on node {} has already started",
+                    request.getCheckpoint().getShardId(),
+                    request.getTargetNode()
+                );
+            }
+            // update the given listener to release the CopyState before it resolves.
+            final ActionListener<GetSegmentFilesResponse> wrappedListener = ActionListener.runBefore(listener, () -> {
+                final SegmentReplicationSourceHandler sourceHandler = allocationIdToHandlers.remove(request.getTargetAllocationId());
+                if (sourceHandler != null) {
+                    removeCopyState(sourceHandler.getCopyState());
+                }
+            });
+            handler.sendFiles(request, wrappedListener);
+        } else {
+            listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+        }
+    }
+
+    /**
+     * Prepare for a Replication event. This method constructs a {@link CopyState} holding files to be sent off of the current
+     * node's store.  This state is intended to be sent back to Replicas before copy is initiated so the replica can perform a diff against its
+     * local store.  It will then build a handler to orchestrate the segment copy that will be stored locally and started on a subsequent request from replicas
+     * with the list of required files.
+     *
+     * @param request         {@link CheckpointInfoRequest}
+     * @param fileChunkWriter {@link FileChunkWriter} writer to handle sending files over the transport layer.
+     * @return {@link CopyState} the built CopyState for this replication event.
+     * @throws IOException - When there is an IO error building CopyState.
+     */
+    CopyState prepareForReplication(CheckpointInfoRequest request, FileChunkWriter fileChunkWriter) throws IOException {
+        final CopyState copyState = getCachedCopyState(request.getCheckpoint());
+        final SegmentReplicationSourceHandler newHandler = createTargetHandler(
+            request.getTargetNode(),
+            copyState,
+            request.getTargetAllocationId(),
+            fileChunkWriter
+        );
+        final SegmentReplicationSourceHandler existingHandler = allocationIdToHandlers.putIfAbsent(
+            request.getTargetAllocationId(),
+            newHandler
+        );
+        // If we are already replicating to this allocation Id, cancel the old and replace with a new execution.
+        // This will clear the old handler & referenced copy state holding an incref'd indexCommit.
+        if (existingHandler != null) {
+            logger.warn("Override handler for allocation id {}", request.getTargetAllocationId());
+            cancelHandlers(handler -> handler.getAllocationId().equals(request.getTargetAllocationId()), "cancel due to retry");
+            assert allocationIdToHandlers.containsKey(request.getTargetAllocationId()) == false;
+            allocationIdToHandlers.put(request.getTargetAllocationId(), newHandler);
+        }
+        assert allocationIdToHandlers.containsKey(request.getTargetAllocationId());
+        return copyState;
+    }
+
+    /**
+     * Cancel all Replication events for the given shard, intended to be called when a primary is shutting down.
+     *
+     * @param shard  {@link IndexShard}
+     * @param reason {@link String} - Reason for the cancel
+     */
+    synchronized void cancel(IndexShard shard, String reason) {
+        cancelHandlers(handler -> handler.getCopyState().getShard().shardId().equals(shard.shardId()), reason);
+    }
+
+    /**
+     * Cancel all Replication events for the given allocation ID, intended to be called when a primary is shutting down.
+     *
+     * @param allocationId {@link String} - Allocation ID.
+     * @param reason       {@link String} - Reason for the cancel
+     */
+    synchronized void cancel(String allocationId, String reason) {
+        final SegmentReplicationSourceHandler handler = allocationIdToHandlers.remove(allocationId);
+        if (handler != null) {
+            handler.cancel(reason);
+            removeCopyState(handler.getCopyState());
+        }
+    }
+
+    /**
+     * Cancel any ongoing replications for a given {@link DiscoveryNode}
+     *
+     * @param node {@link DiscoveryNode} node for which to cancel replication events.
+     */
+    void cancelReplication(DiscoveryNode node) {
+        cancelHandlers(handler -> handler.getTargetNode().equals(node), "Node left");
+    }
+
+    /**
+     * Checks if the {@link #copyStateMap} has the input {@link ReplicationCheckpoint}
+     * as a key by invoking {@link Map#containsKey(Object)}.
+     */
+    boolean isInCopyStateMap(ReplicationCheckpoint replicationCheckpoint) {
+        return copyStateMap.containsKey(replicationCheckpoint);
+    }
+
+    int size() {
+        return allocationIdToHandlers.size();
+    }
+
+    // Visible for tests.
+    Map<String, SegmentReplicationSourceHandler> getHandlers() {
+        return allocationIdToHandlers;
+    }
+
+    int cachedCopyStateSize() {
+        return copyStateMap.size();
+    }
+
+    private SegmentReplicationSourceHandler createTargetHandler(
+        DiscoveryNode node,
+        CopyState copyState,
+        String allocationId,
+        FileChunkWriter fileChunkWriter
+    ) {
+        return new SegmentReplicationSourceHandler(
+            node,
+            fileChunkWriter,
+            copyState.getShard().getThreadPool(),
+            copyState,
+            allocationId,
+            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+            recoverySettings.getMaxConcurrentFileChunks()
+        );
+    }
+
+    /**
+     * Adds the input {@link CopyState} object to {@link #copyStateMap}.
+     * The key is the CopyState's {@link ReplicationCheckpoint} object.
+     */
+    private void addToCopyStateMap(ReplicationCheckpoint checkpoint, CopyState copyState) {
+        copyStateMap.putIfAbsent(checkpoint, copyState);
+    }
+
+    /**
+     * Given a {@link ReplicationCheckpoint}, return the corresponding
+     * {@link CopyState} object, if any, from {@link #copyStateMap}.
+     */
+    private CopyState fetchFromCopyStateMap(ReplicationCheckpoint replicationCheckpoint) {
+        return copyStateMap.get(replicationCheckpoint);
+    }
+
+    /**
+     * Remove a CopyState. Intended to be called after a replication event completes.
+     * This method will remove a copyState from the copyStateMap only if its refCount hits 0.
+     *
+     * @param copyState {@link CopyState}
+     */
+    private synchronized void removeCopyState(CopyState copyState) {
+        if (copyState.decRef() == true) {
+            copyStateMap.remove(copyState.getRequestedReplicationCheckpoint());
+        }
+    }
+
+    /**
+     * Remove handlers from allocationIdToHandlers map based on a filter predicate.
+     * This will also decref the handler's CopyState reference.
+     */
+    private void cancelHandlers(Predicate<? super SegmentReplicationSourceHandler> predicate, String reason) {
+        final List<String> allocationIds = allocationIdToHandlers.values()
+            .stream()
+            .filter(predicate)
+            .map(SegmentReplicationSourceHandler::getAllocationId)
+            .collect(Collectors.toList());
+        if (allocationIds.size() == 0) {
+            return;
+        }
+        logger.warn(() -> new ParameterizedMessage("Cancelling replications for allocationIds {}", allocationIds));
+        for (String allocationId : allocationIds) {
+            cancel(allocationId, reason);
+        }
+    }
+
+    /**
+     * Clear copystate and target handlers for any non insync allocationIds.
+     * @param shardId {@link ShardId}
+     * @param inSyncAllocationIds {@link List} of in-sync allocation Ids.
+     */
+    public void clearOutOfSyncIds(ShardId shardId, Set<String> inSyncAllocationIds) {
+        cancelHandlers(
+            (handler) -> handler.getCopyState().getShard().shardId().equals(shardId)
+                && inSyncAllocationIds.contains(handler.getAllocationId()) == false,
+            "Shard is no longer in-sync with the primary"
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/PrimaryShardReplicationSource.java b/server/src/main/java/org/opensearch/indices/replication/PrimaryShardReplicationSource.java
new file mode 100644
index 0000000000000..9dcd16c53e6f3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/PrimaryShardReplicationSource.java
@@ -0,0 +1,110 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RetryableTransportClient;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.transport.TransportRequestOptions;
+import org.opensearch.transport.TransportService;
+
+import java.util.List;
+
+import static org.opensearch.indices.replication.SegmentReplicationSourceService.Actions.GET_CHECKPOINT_INFO;
+import static org.opensearch.indices.replication.SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES;
+
+/**
+ * Implementation of a {@link SegmentReplicationSource} where the source is a primary node.
+ * This code executes on the target node.
+ *
+ * @opensearch.internal
+ */
+public class PrimaryShardReplicationSource implements SegmentReplicationSource {
+
+    private static final Logger logger = LogManager.getLogger(PrimaryShardReplicationSource.class);
+
+    private final RetryableTransportClient transportClient;
+
+    private final DiscoveryNode sourceNode;
+    private final DiscoveryNode targetNode;
+    private final String targetAllocationId;
+    private final RecoverySettings recoverySettings;
+
+    public PrimaryShardReplicationSource(
+        DiscoveryNode targetNode,
+        String targetAllocationId,
+        TransportService transportService,
+        RecoverySettings recoverySettings,
+        DiscoveryNode sourceNode
+    ) {
+        this.targetAllocationId = targetAllocationId;
+        this.transportClient = new RetryableTransportClient(
+            transportService,
+            sourceNode,
+            recoverySettings.internalActionRetryTimeout(),
+            logger
+        );
+        this.sourceNode = sourceNode;
+        this.targetNode = targetNode;
+        this.recoverySettings = recoverySettings;
+    }
+
+    @Override
+    public void getCheckpointMetadata(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        ActionListener<CheckpointInfoResponse> listener
+    ) {
+        final Writeable.Reader<CheckpointInfoResponse> reader = CheckpointInfoResponse::new;
+        final ActionListener<CheckpointInfoResponse> responseListener = ActionListener.map(listener, r -> r);
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(replicationId, targetAllocationId, targetNode, checkpoint);
+        transportClient.executeRetryableAction(GET_CHECKPOINT_INFO, request, responseListener, reader);
+    }
+
+    @Override
+    public void getSegmentFiles(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        List<StoreFileMetadata> filesToFetch,
+        IndexShard indexShard,
+        ActionListener<GetSegmentFilesResponse> listener
+    ) {
+        final Writeable.Reader<GetSegmentFilesResponse> reader = GetSegmentFilesResponse::new;
+        final ActionListener<GetSegmentFilesResponse> responseListener = ActionListener.map(listener, r -> r);
+        final GetSegmentFilesRequest request = new GetSegmentFilesRequest(
+            replicationId,
+            targetAllocationId,
+            targetNode,
+            filesToFetch,
+            checkpoint
+        );
+        final TransportRequestOptions options = TransportRequestOptions.builder()
+            .withTimeout(recoverySettings.internalActionLongTimeout())
+            .build();
+        transportClient.executeRetryableAction(GET_SEGMENT_FILES, request, options, responseListener, reader);
+    }
+
+    @Override
+    public String getDescription() {
+        return sourceNode.getName();
+    }
+
+    @Override
+    public void cancel() {
+        transportClient.cancel();
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/RemoteSegmentFileChunkWriter.java b/server/src/main/java/org/opensearch/indices/replication/RemoteSegmentFileChunkWriter.java
new file mode 100644
index 0000000000000..b52fe66816098
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/RemoteSegmentFileChunkWriter.java
@@ -0,0 +1,130 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.store.RateLimiter;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.FileChunkRequest;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RetryableTransportClient;
+import org.opensearch.transport.TransportRequestOptions;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Consumer;
+
+/**
+ * This class handles sending file chunks over the transport layer to a target shard.
+ *
+ * @opensearch.internal
+ */
+public final class RemoteSegmentFileChunkWriter implements FileChunkWriter {
+
+    private final AtomicLong requestSeqNoGenerator;
+    private final RetryableTransportClient retryableTransportClient;
+    private final ShardId shardId;
+    private final RecoverySettings recoverySettings;
+    private final long replicationId;
+    private final AtomicLong bytesSinceLastPause = new AtomicLong();
+    private final TransportRequestOptions fileChunkRequestOptions;
+    private final Consumer<Long> onSourceThrottle;
+    private final String action;
+
+    public RemoteSegmentFileChunkWriter(
+        long replicationId,
+        RecoverySettings recoverySettings,
+        RetryableTransportClient retryableTransportClient,
+        ShardId shardId,
+        String action,
+        AtomicLong requestSeqNoGenerator,
+        Consumer<Long> onSourceThrottle
+    ) {
+        this.replicationId = replicationId;
+        this.recoverySettings = recoverySettings;
+        this.retryableTransportClient = retryableTransportClient;
+        this.shardId = shardId;
+        this.requestSeqNoGenerator = requestSeqNoGenerator;
+        this.onSourceThrottle = onSourceThrottle;
+        this.fileChunkRequestOptions = TransportRequestOptions.builder()
+            .withType(TransportRequestOptions.Type.RECOVERY)
+            .withTimeout(recoverySettings.internalActionTimeout())
+            .build();
+
+        this.action = action;
+    }
+
+    @Override
+    public void writeFileChunk(
+        StoreFileMetadata fileMetadata,
+        long position,
+        BytesReference content,
+        boolean lastChunk,
+        int totalTranslogOps,
+        ActionListener<Void> listener
+    ) {
+        // Pause using the rate limiter, if desired, to throttle the recovery
+        final long throttleTimeInNanos;
+        // always fetch the ratelimiter - it might be updated in real-time on the recovery settings
+        final RateLimiter rl = recoverySettings.rateLimiter();
+        if (rl != null) {
+            long bytes = bytesSinceLastPause.addAndGet(content.length());
+            if (bytes > rl.getMinPauseCheckBytes()) {
+                // Time to pause
+                bytesSinceLastPause.addAndGet(-bytes);
+                try {
+                    throttleTimeInNanos = rl.pause(bytes);
+                    onSourceThrottle.accept(throttleTimeInNanos);
+                } catch (IOException e) {
+                    throw new OpenSearchException("failed to pause recovery", e);
+                }
+            } else {
+                throttleTimeInNanos = 0;
+            }
+        } else {
+            throttleTimeInNanos = 0;
+        }
+
+        final long requestSeqNo = requestSeqNoGenerator.getAndIncrement();
+        /* we send estimateTotalOperations with every request since we collect stats on the target and that way we can
+         * see how many translog ops we accumulate while copying files across the network. A future optimization
+         * would be in to restart file copy again (new deltas) if we have too many translog ops are piling up.
+         */
+        final FileChunkRequest request = new FileChunkRequest(
+            replicationId,
+            requestSeqNo,
+            shardId,
+            fileMetadata,
+            position,
+            content,
+            lastChunk,
+            totalTranslogOps,
+            throttleTimeInNanos
+        );
+        final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
+        retryableTransportClient.executeRetryableAction(
+            action,
+            request,
+            fileChunkRequestOptions,
+            ActionListener.map(listener, r -> null),
+            reader
+        );
+    }
+
+    @Override
+    public void cancel() {
+        retryableTransportClient.cancel();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/RemoteStoreReplicationSource.java b/server/src/main/java/org/opensearch/indices/replication/RemoteStoreReplicationSource.java
new file mode 100644
index 0000000000000..e17c5293c38ac
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/RemoteStoreReplicationSource.java
@@ -0,0 +1,156 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.util.Version;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardState;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Implementation of a {@link SegmentReplicationSource} where the source is remote store.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreReplicationSource implements SegmentReplicationSource {
+
+    private static final Logger logger = LogManager.getLogger(RemoteStoreReplicationSource.class);
+
+    private final IndexShard indexShard;
+    private final RemoteSegmentStoreDirectory remoteDirectory;
+
+    public RemoteStoreReplicationSource(IndexShard indexShard) {
+        this.indexShard = indexShard;
+        FilterDirectory remoteStoreDirectory = (FilterDirectory) indexShard.remoteStore().directory();
+        FilterDirectory byteSizeCachingStoreDirectory = (FilterDirectory) remoteStoreDirectory.getDelegate();
+        this.remoteDirectory = (RemoteSegmentStoreDirectory) byteSizeCachingStoreDirectory.getDelegate();
+    }
+
+    @Override
+    public void getCheckpointMetadata(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        ActionListener<CheckpointInfoResponse> listener
+    ) {
+        Map<String, StoreFileMetadata> metadataMap;
+        // TODO: Need to figure out a way to pass this information for segment metadata via remote store.
+        try (final GatedCloseable<SegmentInfos> segmentInfosSnapshot = indexShard.getSegmentInfosSnapshot()) {
+            final Version version = segmentInfosSnapshot.get().getCommitLuceneVersion();
+            RemoteSegmentMetadata mdFile = remoteDirectory.init();
+            // During initial recovery flow, the remote store might not
+            // have metadata as primary hasn't uploaded anything yet.
+            if (mdFile == null && indexShard.state().equals(IndexShardState.STARTED) == false) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, Collections.emptyMap(), null));
+                return;
+            }
+            assert mdFile != null : "Remote metadata file can't be null if shard is active " + indexShard.state();
+            metadataMap = mdFile.getMetadata()
+                .entrySet()
+                .stream()
+                .collect(
+                    Collectors.toMap(
+                        e -> e.getKey(),
+                        e -> new StoreFileMetadata(
+                            e.getValue().getOriginalFilename(),
+                            e.getValue().getLength(),
+                            Store.digestToString(Long.valueOf(e.getValue().getChecksum())),
+                            version,
+                            null
+                        )
+                    )
+                );
+            listener.onResponse(new CheckpointInfoResponse(mdFile.getReplicationCheckpoint(), metadataMap, mdFile.getSegmentInfosBytes()));
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
+    @Override
+    public void getSegmentFiles(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        List<StoreFileMetadata> filesToFetch,
+        IndexShard indexShard,
+        ActionListener<GetSegmentFilesResponse> listener
+    ) {
+        try {
+            if (filesToFetch.isEmpty()) {
+                listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+                return;
+            }
+            logger.debug("Downloading segment files from remote store {}", filesToFetch);
+
+            RemoteSegmentMetadata remoteSegmentMetadata = remoteDirectory.readLatestMetadataFile();
+            List<StoreFileMetadata> toDownloadSegments = new ArrayList<>();
+            Collection<String> directoryFiles = List.of(indexShard.store().directory().listAll());
+            if (remoteSegmentMetadata != null) {
+                try {
+                    indexShard.store().incRef();
+                    indexShard.remoteStore().incRef();
+                    final Directory storeDirectory = indexShard.store().directory();
+                    final ShardPath shardPath = indexShard.shardPath();
+                    for (StoreFileMetadata fileMetadata : filesToFetch) {
+                        String file = fileMetadata.name();
+                        assert directoryFiles.contains(file) == false : "Local store already contains the file " + file;
+                        toDownloadSegments.add(fileMetadata);
+                    }
+                    downloadSegments(storeDirectory, remoteDirectory, toDownloadSegments, shardPath, listener);
+                    logger.debug("Downloaded segment files from remote store {}", toDownloadSegments);
+                } finally {
+                    indexShard.store().decRef();
+                    indexShard.remoteStore().decRef();
+                }
+            }
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
+    private void downloadSegments(
+        Directory storeDirectory,
+        RemoteSegmentStoreDirectory remoteStoreDirectory,
+        List<StoreFileMetadata> toDownloadSegments,
+        ShardPath shardPath,
+        ActionListener<GetSegmentFilesResponse> completionListener
+    ) {
+        final Path indexPath = shardPath == null ? null : shardPath.resolveIndex();
+        for (StoreFileMetadata storeFileMetadata : toDownloadSegments) {
+            final PlainActionFuture<String> segmentListener = PlainActionFuture.newFuture();
+            remoteStoreDirectory.copyTo(storeFileMetadata.name(), storeDirectory, indexPath, segmentListener);
+            segmentListener.actionGet();
+        }
+        completionListener.onResponse(new GetSegmentFilesResponse(toDownloadSegments));
+    }
+
+    @Override
+    public String getDescription() {
+        return "RemoteStoreReplicationSource";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentFileTransferHandler.java b/server/src/main/java/org/opensearch/indices/replication/SegmentFileTransferHandler.java
new file mode 100644
index 0000000000000..a70700b64eb6e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentFileTransferHandler.java
@@ -0,0 +1,239 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.util.ArrayUtil;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lucene.store.InputStreamIndexInput;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.MultiChunkTransfer;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.RemoteTransportException;
+import org.opensearch.transport.Transports;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Deque;
+import java.util.concurrent.ConcurrentLinkedDeque;
+import java.util.function.IntSupplier;
+
+/**
+ * SegmentFileSender handles building and starting a {@link MultiChunkTransfer} to orchestrate sending chunks to a given targetNode.
+ * This class delegates to a {@link FileChunkWriter} to handle the transport of chunks.
+ *
+ * @opensearch.internal
+ * // TODO: make this package-private after combining recovery and replication into single package.
+ */
+public final class SegmentFileTransferHandler {
+
+    private final Logger logger;
+    private final IndexShard shard;
+    private final FileChunkWriter chunkWriter;
+    private final ThreadPool threadPool;
+    private final int chunkSizeInBytes;
+    private final int maxConcurrentFileChunks;
+    private final DiscoveryNode targetNode;
+    private final CancellableThreads cancellableThreads;
+
+    public SegmentFileTransferHandler(
+        IndexShard shard,
+        DiscoveryNode targetNode,
+        FileChunkWriter chunkWriter,
+        Logger logger,
+        ThreadPool threadPool,
+        CancellableThreads cancellableThreads,
+        int fileChunkSizeInBytes,
+        int maxConcurrentFileChunks
+    ) {
+        this.shard = shard;
+        this.targetNode = targetNode;
+        this.chunkWriter = chunkWriter;
+        this.logger = logger;
+        this.threadPool = threadPool;
+        this.cancellableThreads = cancellableThreads;
+        this.chunkSizeInBytes = fileChunkSizeInBytes;
+        // if the target is on an old version, it won't be able to handle out-of-order file chunks.
+        this.maxConcurrentFileChunks = maxConcurrentFileChunks;
+    }
+
+    /**
+     * Returns a closeable {@link MultiChunkTransfer} to initiate sending a list of files.
+     * Callers are responsible for starting the transfer and closing the resource.
+     * @param store {@link Store}
+     * @param files {@link StoreFileMetadata[]}
+     * @param translogOps {@link IntSupplier}
+     * @param listener {@link ActionListener}
+     * @return {@link MultiChunkTransfer}
+     */
+    public MultiChunkTransfer<StoreFileMetadata, FileChunk> createTransfer(
+        Store store,
+        StoreFileMetadata[] files,
+        IntSupplier translogOps,
+        ActionListener<Void> listener
+    ) {
+        ArrayUtil.timSort(files, Comparator.comparingLong(StoreFileMetadata::length)); // send smallest first
+        return new MultiChunkTransfer<>(logger, threadPool.getThreadContext(), listener, maxConcurrentFileChunks, Arrays.asList(files)) {
+
+            final Deque<byte[]> buffers = new ConcurrentLinkedDeque<>();
+            InputStreamIndexInput currentInput = null;
+            long offset = 0;
+
+            @Override
+            protected void onNewResource(StoreFileMetadata md) throws IOException {
+                offset = 0;
+                IOUtils.close(currentInput, () -> currentInput = null);
+                final IndexInput indexInput = store.directory().openInput(md.name(), IOContext.READONCE);
+                currentInput = new InputStreamIndexInput(indexInput, md.length()) {
+                    @Override
+                    public void close() throws IOException {
+                        IOUtils.close(indexInput, super::close); // InputStreamIndexInput's close is a noop
+                    }
+                };
+            }
+
+            private byte[] acquireBuffer() {
+                final byte[] buffer = buffers.pollFirst();
+                if (buffer != null) {
+                    return buffer;
+                }
+                return new byte[chunkSizeInBytes];
+            }
+
+            @Override
+            protected FileChunk nextChunkRequest(StoreFileMetadata md) throws IOException {
+                assert Transports.assertNotTransportThread("read file chunk");
+                cancellableThreads.checkForCancel();
+                final byte[] buffer = acquireBuffer();
+                final int bytesRead = currentInput.read(buffer);
+                if (bytesRead == -1) {
+                    throw new CorruptIndexException("file truncated; length=" + md.length() + " offset=" + offset, md.name());
+                }
+                final boolean lastChunk = offset + bytesRead == md.length();
+                final FileChunk chunk = new FileChunk(
+                    md,
+                    new BytesArray(buffer, 0, bytesRead),
+                    offset,
+                    lastChunk,
+                    () -> buffers.addFirst(buffer)
+                );
+                offset += bytesRead;
+                return chunk;
+            }
+
+            @Override
+            protected void executeChunkRequest(FileChunk request, ActionListener<Void> listener1) {
+                cancellableThreads.checkForCancel();
+                chunkWriter.writeFileChunk(
+                    request.md,
+                    request.position,
+                    request.content,
+                    request.lastChunk,
+                    translogOps.getAsInt(),
+                    ActionListener.runBefore(listener1, request::close)
+                );
+            }
+
+            @Override
+            protected void handleError(StoreFileMetadata md, Exception e) throws Exception {
+                handleErrorOnSendFiles(store, e, new StoreFileMetadata[] { md });
+            }
+
+            @Override
+            public void close() throws IOException {
+                IOUtils.close(currentInput, () -> currentInput = null);
+            }
+        };
+    }
+
+    public void handleErrorOnSendFiles(Store store, Exception e, StoreFileMetadata[] mds) throws Exception {
+        final IOException corruptIndexException = ExceptionsHelper.unwrapCorruption(e);
+        assert Transports.assertNotTransportThread(this + "[handle error on send/clean files]");
+        if (corruptIndexException != null) {
+            Exception localException = null;
+            for (StoreFileMetadata md : mds) {
+                cancellableThreads.checkForCancel();
+                logger.debug("checking integrity for file {} after remove corruption exception", md);
+                if (store.checkIntegrityNoException(md) == false) { // we are corrupted on the primary -- fail!
+                    logger.warn("{} Corrupted file detected {} checksum mismatch", shard.shardId(), md);
+                    if (localException == null) {
+                        localException = corruptIndexException;
+                    }
+                    shard.failShard("error sending files", corruptIndexException);
+                }
+            }
+            if (localException != null) {
+                throw localException;
+            } else { // corruption has happened on the way to replica
+                RemoteTransportException remoteException = new RemoteTransportException(
+                    "File corruption occurred on recovery but checksums are ok",
+                    null
+                );
+                remoteException.addSuppressed(e);
+                logger.warn(
+                    () -> new ParameterizedMessage(
+                        "{} Remote file corruption on node {}, recovering {}. local checksum OK",
+                        shard.shardId(),
+                        targetNode,
+                        mds
+                    ),
+                    corruptIndexException
+                );
+                throw remoteException;
+            }
+        }
+        throw e;
+    }
+
+    /**
+     * A file chunk from the recovery source
+     *
+     * @opensearch.internal
+     */
+    public static final class FileChunk implements MultiChunkTransfer.ChunkRequest, Releasable {
+        final StoreFileMetadata md;
+        final BytesReference content;
+        final long position;
+        final boolean lastChunk;
+        final Releasable onClose;
+
+        FileChunk(StoreFileMetadata md, BytesReference content, long position, boolean lastChunk, Releasable onClose) {
+            this.md = md;
+            this.content = content;
+            this.position = position;
+            this.lastChunk = lastChunk;
+            this.onClose = onClose;
+        }
+
+        @Override
+        public boolean lastChunk() {
+            return lastChunk;
+        }
+
+        @Override
+        public void close() {
+            onClose.close();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSource.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSource.java
new file mode 100644
index 0000000000000..6676b5b667e42
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSource.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.common.util.CancellableThreads.ExecutionCancelledException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.util.List;
+
+/**
+ * Represents the source of a replication event.
+ *
+ * @opensearch.internal
+ */
+public interface SegmentReplicationSource {
+
+    /**
+     * Get Metadata for a ReplicationCheckpoint.
+     *
+     * @param replicationId {@link long} - ID of the replication event.
+     * @param checkpoint    {@link ReplicationCheckpoint} Checkpoint to fetch metadata for.
+     * @param listener      {@link ActionListener} listener that completes with a {@link CheckpointInfoResponse}.
+     */
+    void getCheckpointMetadata(long replicationId, ReplicationCheckpoint checkpoint, ActionListener<CheckpointInfoResponse> listener);
+
+    /**
+     * Fetch the requested segment files.  Passes a listener that completes when files are stored locally.
+     *
+     * @param replicationId {@link long} - ID of the replication event.
+     * @param checkpoint    {@link ReplicationCheckpoint} Checkpoint to fetch metadata for.
+     * @param filesToFetch  {@link List} List of files to fetch.
+     * @param indexShard    {@link IndexShard} Reference to the IndexShard.
+     * @param listener      {@link ActionListener} Listener that completes with the list of files copied.
+     */
+    void getSegmentFiles(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        List<StoreFileMetadata> filesToFetch,
+        IndexShard indexShard,
+        ActionListener<GetSegmentFilesResponse> listener
+    );
+
+    /**
+     * Get the source description
+     */
+    String getDescription();
+
+    /**
+     * Cancel any ongoing requests, should resolve any ongoing listeners with onFailure with a {@link ExecutionCancelledException}.
+     */
+    default void cancel() {}
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceFactory.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceFactory.java
new file mode 100644
index 0000000000000..852003c9f3e4d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceFactory.java
@@ -0,0 +1,58 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.transport.TransportService;
+
+/**
+ * Factory to build {@link SegmentReplicationSource} used by {@link SegmentReplicationTargetService}.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationSourceFactory {
+
+    private final TransportService transportService;
+    private final RecoverySettings recoverySettings;
+    private final ClusterService clusterService;
+
+    public SegmentReplicationSourceFactory(
+        TransportService transportService,
+        RecoverySettings recoverySettings,
+        ClusterService clusterService
+    ) {
+        this.transportService = transportService;
+        this.recoverySettings = recoverySettings;
+        this.clusterService = clusterService;
+    }
+
+    public SegmentReplicationSource get(IndexShard shard) {
+        if (shard.indexSettings().isSegRepWithRemoteEnabled()) {
+            return new RemoteStoreReplicationSource(shard);
+        } else {
+            return new PrimaryShardReplicationSource(
+                shard.recoveryState().getTargetNode(),
+                shard.routingEntry().allocationId().getId(),
+                transportService,
+                recoverySettings,
+                getPrimaryNode(shard.shardId())
+            );
+        }
+    }
+
+    private DiscoveryNode getPrimaryNode(ShardId shardId) {
+        ShardRouting primaryShard = clusterService.state().routingTable().shardRoutingTable(shardId).primaryShard();
+        return clusterService.state().nodes().get(primaryShard.currentNodeId());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceHandler.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceHandler.java
new file mode 100644
index 0000000000000..e2c47b0fb3159
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceHandler.java
@@ -0,0 +1,212 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.Logger;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.StepListener;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.ListenableFuture;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.DelayRecoveryException;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.MultiChunkTransfer;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationTimer;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transports;
+
+import java.io.Closeable;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
+
+/**
+ * Orchestrates sending requested segment files to a target shard.
+ *
+ * @opensearch.internal
+ */
+class SegmentReplicationSourceHandler {
+
+    private final IndexShard shard;
+    private final CopyState copyState;
+    private final SegmentFileTransferHandler segmentFileTransferHandler;
+    private final CancellableThreads cancellableThreads = new CancellableThreads();
+    private final ListenableFuture<GetSegmentFilesResponse> future = new ListenableFuture<>();
+    private final List<Closeable> resources = new CopyOnWriteArrayList<>();
+    private final Logger logger;
+    private final AtomicBoolean isReplicating = new AtomicBoolean();
+    private final DiscoveryNode targetNode;
+    private final String allocationId;
+
+    private final FileChunkWriter writer;
+
+    /**
+     * Constructor.
+     *
+     * @param targetNode              - {@link DiscoveryNode} target node where files should be sent.
+     * @param writer                  {@link FileChunkWriter} implementation that sends file chunks over the transport layer.
+     * @param threadPool              {@link ThreadPool} Thread pool.
+     * @param copyState               {@link CopyState} CopyState holding segment file metadata.
+     * @param fileChunkSizeInBytes    {@link Integer}
+     * @param maxConcurrentFileChunks {@link Integer}
+     */
+    SegmentReplicationSourceHandler(
+        DiscoveryNode targetNode,
+        FileChunkWriter writer,
+        ThreadPool threadPool,
+        CopyState copyState,
+        String allocationId,
+        int fileChunkSizeInBytes,
+        int maxConcurrentFileChunks
+    ) {
+        this.targetNode = targetNode;
+        this.shard = copyState.getShard();
+        this.logger = Loggers.getLogger(
+            SegmentReplicationSourceHandler.class,
+            copyState.getShard().shardId(),
+            "sending segments to " + targetNode.getName()
+        );
+        this.segmentFileTransferHandler = new SegmentFileTransferHandler(
+            copyState.getShard(),
+            targetNode,
+            writer,
+            logger,
+            threadPool,
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
+        this.allocationId = allocationId;
+        this.copyState = copyState;
+        this.writer = writer;
+    }
+
+    /**
+     * Sends Segment files from the local node to the given target.
+     *
+     * @param request  {@link GetSegmentFilesRequest} request object containing list of files to be sent.
+     * @param listener {@link ActionListener} that completes with the list of files sent.
+     */
+    public synchronized void sendFiles(GetSegmentFilesRequest request, ActionListener<GetSegmentFilesResponse> listener) {
+        // Short circuit when no files to transfer
+        if (request.getFilesToFetch().isEmpty()) {
+            // before completion, alert the primary of the replica's state.
+            shard.updateVisibleCheckpointForShard(request.getTargetAllocationId(), copyState.getCheckpoint());
+            listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+            return;
+        }
+
+        final ReplicationTimer timer = new ReplicationTimer();
+        if (isReplicating.compareAndSet(false, true) == false) {
+            throw new OpenSearchException("Replication to {} is already running.", shard.shardId());
+        }
+        future.addListener(listener, OpenSearchExecutors.newDirectExecutorService());
+        final Closeable releaseResources = () -> IOUtils.close(resources);
+        try {
+            timer.start();
+            cancellableThreads.setOnCancel((reason, beforeCancelEx) -> {
+                final RuntimeException e = new CancellableThreads.ExecutionCancelledException(
+                    "replication was canceled reason [" + reason + "]"
+                );
+                if (beforeCancelEx != null) {
+                    e.addSuppressed(beforeCancelEx);
+                }
+                IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
+                throw e;
+            });
+            final Consumer<Exception> onFailure = e -> {
+                assert Transports.assertNotTransportThread(SegmentReplicationSourceHandler.this + "[onFailure]");
+                IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
+                timer.stop();
+                logger.trace(
+                    "[replication id {}] Source node failed to send files to target node [{}], timing: {}",
+                    request.getReplicationId(),
+                    request.getTargetNode().getId(),
+                    timer.time()
+                );
+            };
+            cancellableThreads.checkForCancel();
+            final IndexShardRoutingTable routingTable = shard.getReplicationGroup().getRoutingTable();
+            ShardRouting targetShardRouting = routingTable.getByAllocationId(request.getTargetAllocationId());
+            if (targetShardRouting == null) {
+                logger.debug("delaying replication of {} as it is not listed as assigned to target node {}", shard.shardId(), targetNode);
+                throw new DelayRecoveryException("source node does not have the shard listed in its state as allocated on the node");
+            }
+
+            final StepListener<Void> sendFileStep = new StepListener<>();
+            Set<String> storeFiles = new HashSet<>(Arrays.asList(shard.store().directory().listAll()));
+            final StoreFileMetadata[] storeFileMetadata = request.getFilesToFetch()
+                .stream()
+                .filter(file -> storeFiles.contains(file.name()))
+                .toArray(StoreFileMetadata[]::new);
+
+            final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = segmentFileTransferHandler
+                .createTransfer(shard.store(), storeFileMetadata, () -> 0, sendFileStep);
+            resources.add(transfer);
+            cancellableThreads.checkForCancel();
+            transfer.start();
+
+            sendFileStep.whenComplete(r -> {
+                try {
+                    shard.updateVisibleCheckpointForShard(allocationId, copyState.getCheckpoint());
+                    future.onResponse(new GetSegmentFilesResponse(List.of(storeFileMetadata)));
+                    timer.stop();
+                } finally {
+                    IOUtils.close(resources);
+                    logger.trace(
+                        "[replication id {}] Source node completed sending files to target node [{}], timing: {}",
+                        request.getReplicationId(),
+                        request.getTargetNode().getId(),
+                        timer.time()
+                    );
+                }
+            }, onFailure);
+        } catch (Exception e) {
+            IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
+        }
+    }
+
+    /**
+     * Cancels the replication and interrupts all eligible threads.
+     */
+    public void cancel(String reason) {
+        writer.cancel();
+        cancellableThreads.cancel(reason);
+    }
+
+    CopyState getCopyState() {
+        return copyState;
+    }
+
+    public boolean isReplicating() {
+        return isReplicating.get();
+    }
+
+    public DiscoveryNode getTargetNode() {
+        return targetNode;
+    }
+
+    public String getAllocationId() {
+        return allocationId;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceService.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceService.java
new file mode 100644
index 0000000000000..4062f9702fb3a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceService.java
@@ -0,0 +1,239 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.action.support.ChannelActionListener;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterStateListener;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.shard.IndexEventListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RetryableTransportClient;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationTimer;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportChannel;
+import org.opensearch.transport.TransportRequestHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Service class that handles segment replication requests from replica shards.
+ * Typically, the "source" is a primary shard. This code executes on the source node.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationSourceService extends AbstractLifecycleComponent implements ClusterStateListener, IndexEventListener {
+
+    private static final Logger logger = LogManager.getLogger(SegmentReplicationSourceService.class);
+    private final RecoverySettings recoverySettings;
+    private final TransportService transportService;
+    private final IndicesService indicesService;
+
+    /**
+     * Internal actions used by the segment replication source service on the primary shard
+     *
+     * @opensearch.internal
+     */
+    public static class Actions {
+
+        public static final String GET_CHECKPOINT_INFO = "internal:index/shard/replication/get_checkpoint_info";
+        public static final String GET_SEGMENT_FILES = "internal:index/shard/replication/get_segment_files";
+        public static final String UPDATE_VISIBLE_CHECKPOINT = "internal:index/shard/replication/update_visible_checkpoint";
+    }
+
+    private final OngoingSegmentReplications ongoingSegmentReplications;
+
+    protected SegmentReplicationSourceService(
+        IndicesService indicesService,
+        TransportService transportService,
+        RecoverySettings recoverySettings,
+        OngoingSegmentReplications ongoingSegmentReplications
+    ) {
+        this.transportService = transportService;
+        this.indicesService = indicesService;
+        this.recoverySettings = recoverySettings;
+        this.ongoingSegmentReplications = ongoingSegmentReplications;
+        transportService.registerRequestHandler(
+            Actions.GET_CHECKPOINT_INFO,
+            ThreadPool.Names.GENERIC,
+            CheckpointInfoRequest::new,
+            new CheckpointInfoRequestHandler()
+        );
+        transportService.registerRequestHandler(
+            Actions.GET_SEGMENT_FILES,
+            ThreadPool.Names.GENERIC,
+            GetSegmentFilesRequest::new,
+            new GetSegmentFilesRequestHandler()
+        );
+        transportService.registerRequestHandler(
+            Actions.UPDATE_VISIBLE_CHECKPOINT,
+            ThreadPool.Names.GENERIC,
+            UpdateVisibleCheckpointRequest::new,
+            new UpdateVisibleCheckpointRequestHandler()
+        );
+    }
+
+    public SegmentReplicationSourceService(
+        IndicesService indicesService,
+        TransportService transportService,
+        RecoverySettings recoverySettings
+    ) {
+        this(indicesService, transportService, recoverySettings, new OngoingSegmentReplications(indicesService, recoverySettings));
+    }
+
+    private class CheckpointInfoRequestHandler implements TransportRequestHandler<CheckpointInfoRequest> {
+        @Override
+        public void messageReceived(CheckpointInfoRequest request, TransportChannel channel, Task task) throws Exception {
+            final ReplicationTimer timer = new ReplicationTimer();
+            timer.start();
+            final RemoteSegmentFileChunkWriter segmentSegmentFileChunkWriter = new RemoteSegmentFileChunkWriter(
+                request.getReplicationId(),
+                recoverySettings,
+                new RetryableTransportClient(
+                    transportService,
+                    request.getTargetNode(),
+                    recoverySettings.internalActionRetryTimeout(),
+                    logger
+                ),
+                request.getCheckpoint().getShardId(),
+                SegmentReplicationTargetService.Actions.FILE_CHUNK,
+                new AtomicLong(0),
+                (throttleTime) -> {}
+            );
+            final CopyState copyState = ongoingSegmentReplications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+            channel.sendResponse(
+                new CheckpointInfoResponse(copyState.getCheckpoint(), copyState.getMetadataMap(), copyState.getInfosBytes())
+            );
+            timer.stop();
+            logger.trace(
+                new ParameterizedMessage(
+                    "[replication id {}] Source node sent checkpoint info [{}] to target node [{}], timing: {}",
+                    request.getReplicationId(),
+                    copyState.getCheckpoint(),
+                    request.getTargetNode().getId(),
+                    timer.time()
+                )
+            );
+        }
+    }
+
+    private class GetSegmentFilesRequestHandler implements TransportRequestHandler<GetSegmentFilesRequest> {
+        @Override
+        public void messageReceived(GetSegmentFilesRequest request, TransportChannel channel, Task task) throws Exception {
+            ongoingSegmentReplications.startSegmentCopy(request, new ChannelActionListener<>(channel, Actions.GET_SEGMENT_FILES, request));
+        }
+    }
+
+    private class UpdateVisibleCheckpointRequestHandler implements TransportRequestHandler<UpdateVisibleCheckpointRequest> {
+        @Override
+        public void messageReceived(UpdateVisibleCheckpointRequest request, TransportChannel channel, Task task) throws Exception {
+            try {
+                IndexService indexService = indicesService.indexServiceSafe(request.getPrimaryShardId().getIndex());
+                IndexShard indexShard = indexService.getShard(request.getPrimaryShardId().id());
+                indexShard.updateVisibleCheckpointForShard(request.getTargetAllocationId(), request.getCheckpoint());
+                channel.sendResponse(TransportResponse.Empty.INSTANCE);
+            } catch (Exception e) {
+                channel.sendResponse(e);
+            }
+        }
+    }
+
+    @Override
+    public void clusterChanged(ClusterChangedEvent event) {
+        if (event.nodesRemoved()) {
+            for (DiscoveryNode removedNode : event.nodesDelta().removedNodes()) {
+                ongoingSegmentReplications.cancelReplication(removedNode);
+            }
+        }
+        // if a replica for one of the primary shards on this node has closed,
+        // we need to ensure its state has cleared up in ongoing replications.
+        if (event.routingTableChanged()) {
+            for (IndexService indexService : indicesService) {
+                if (indexService.getIndexSettings().isSegRepEnabled()) {
+                    for (IndexShard indexShard : indexService) {
+                        if (indexShard.routingEntry().primary()) {
+                            final IndexMetadata indexMetadata = indexService.getIndexSettings().getIndexMetadata();
+                            final Set<String> inSyncAllocationIds = new HashSet<>(
+                                indexMetadata.inSyncAllocationIds(indexShard.shardId().id())
+                            );
+                            if (indexShard.isPrimaryMode()) {
+                                final Set<String> shardTrackerInSyncIds = indexShard.getReplicationGroup().getInSyncAllocationIds();
+                                inSyncAllocationIds.addAll(shardTrackerInSyncIds);
+                            }
+                            ongoingSegmentReplications.clearOutOfSyncIds(indexShard.shardId(), inSyncAllocationIds);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
+    protected void doStart() {
+        final ClusterService clusterService = indicesService.clusterService();
+        if (DiscoveryNode.isDataNode(clusterService.getSettings())) {
+            clusterService.addListener(this);
+        }
+    }
+
+    @Override
+    protected void doStop() {
+        final ClusterService clusterService = indicesService.clusterService();
+        if (DiscoveryNode.isDataNode(clusterService.getSettings())) {
+            indicesService.clusterService().removeListener(this);
+        }
+    }
+
+    @Override
+    protected void doClose() throws IOException {
+
+    }
+
+    /**
+     *
+     * Cancels any replications on this node to a replica shard that is about to be closed.
+     */
+    @Override
+    public void beforeIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {
+        if (indexShard != null && indexShard.indexSettings().isSegRepEnabled()) {
+            ongoingSegmentReplications.cancel(indexShard, "shard is closed");
+        }
+    }
+
+    /**
+     * Cancels any replications on this node to a replica that has been promoted as primary.
+     */
+    @Override
+    public void shardRoutingChanged(IndexShard indexShard, @Nullable ShardRouting oldRouting, ShardRouting newRouting) {
+        if (indexShard != null && indexShard.indexSettings().isSegRepEnabled() && oldRouting.primary() == false && newRouting.primary()) {
+            ongoingSegmentReplications.cancel(indexShard.routingEntry().allocationId().getId(), "Relocating primary shard.");
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationState.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationState.java
new file mode 100644
index 0000000000000..9b5b1f4a1468e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationState.java
@@ -0,0 +1,311 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationTimer;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * ReplicationState implementation to track Segment Replication events.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationState implements ReplicationState, ToXContentFragment, Writeable {
+
+    /**
+     * The stage of the recovery state
+     *
+     * @opensearch.internal
+     */
+    public enum Stage {
+        DONE((byte) 0),
+        INIT((byte) 1),
+        REPLICATING((byte) 2),
+        GET_CHECKPOINT_INFO((byte) 3),
+        FILE_DIFF((byte) 4),
+        GET_FILES((byte) 5),
+        FINALIZE_REPLICATION((byte) 6);
+
+        private static final Stage[] STAGES = new Stage[Stage.values().length];
+
+        static {
+            for (Stage stage : Stage.values()) {
+                assert stage.id() < STAGES.length && stage.id() >= 0;
+                STAGES[stage.id] = stage;
+            }
+        }
+
+        private final byte id;
+
+        Stage(byte id) {
+            this.id = id;
+        }
+
+        public byte id() {
+            return id;
+        }
+
+        public static Stage fromId(byte id) {
+            if (id < 0 || id >= STAGES.length) {
+                throw new IllegalArgumentException("No mapping for id [" + id + "]");
+            }
+            return STAGES[id];
+        }
+    }
+
+    private Stage stage;
+    private ReplicationLuceneIndex index;
+
+    private final ReplicationTimer overallTimer;
+    private final Map<String, Long> timingData;
+    private final ReplicationTimer stageTimer;
+    private long replicationId;
+    private final ShardRouting shardRouting;
+    private String sourceDescription;
+    private DiscoveryNode targetNode;
+
+    public ShardRouting getShardRouting() {
+        return shardRouting;
+    }
+
+    @Override
+    public ReplicationLuceneIndex getIndex() {
+        return index;
+    }
+
+    public long getReplicationId() {
+        return replicationId;
+    }
+
+    @Override
+    public ReplicationTimer getTimer() {
+        return overallTimer;
+    }
+
+    public Stage getStage() {
+        return this.stage;
+    }
+
+    public String getSourceDescription() {
+
+        return sourceDescription;
+    }
+
+    public DiscoveryNode getTargetNode() {
+        return targetNode;
+    }
+
+    public Map<String, Long> getTimingData() {
+        return timingData;
+    }
+
+    public TimeValue getReplicatingStageTime() {
+        long time = timingData.getOrDefault(Stage.REPLICATING.toString(), 0L);
+        return new TimeValue(time);
+    }
+
+    public TimeValue getGetCheckpointInfoStageTime() {
+        long time = timingData.getOrDefault(Stage.GET_CHECKPOINT_INFO.toString(), 0L);
+        return new TimeValue(time);
+    }
+
+    public TimeValue getFileDiffStageTime() {
+        long time = timingData.getOrDefault(Stage.FILE_DIFF.toString(), 0L);
+        return new TimeValue(time);
+    }
+
+    public TimeValue getGetFileStageTime() {
+        long time = timingData.getOrDefault(Stage.GET_FILES.toString(), 0L);
+        return new TimeValue(time);
+    }
+
+    public TimeValue getFinalizeReplicationStageTime() {
+        long time = timingData.getOrDefault(Stage.FINALIZE_REPLICATION.toString(), 0L);
+        return new TimeValue(time);
+    }
+
+    public SegmentReplicationState(
+        ShardRouting shardRouting,
+        ReplicationLuceneIndex index,
+        long replicationId,
+        String sourceDescription,
+        DiscoveryNode targetNode
+    ) {
+        this.index = index;
+        this.shardRouting = shardRouting;
+        this.replicationId = replicationId;
+        this.sourceDescription = sourceDescription;
+        this.targetNode = targetNode;
+        // Timing data will have as many entries as stages, plus one
+        timingData = new ConcurrentHashMap<>(Stage.values().length + 1);
+        overallTimer = new ReplicationTimer();
+        stageTimer = new ReplicationTimer();
+        setStage(Stage.INIT);
+        stageTimer.start();
+    }
+
+    public SegmentReplicationState(StreamInput in) throws IOException {
+        index = new ReplicationLuceneIndex(in);
+        shardRouting = new ShardRouting(in);
+        stage = in.readEnum(Stage.class);
+        replicationId = in.readLong();
+        overallTimer = new ReplicationTimer(in);
+        stageTimer = new ReplicationTimer(in);
+        timingData = in.readMap(StreamInput::readString, StreamInput::readLong);
+        sourceDescription = in.readString();
+        targetNode = new DiscoveryNode(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        index.writeTo(out);
+        shardRouting.writeTo(out);
+        out.writeEnum(stage);
+        out.writeLong(replicationId);
+        overallTimer.writeTo(out);
+        stageTimer.writeTo(out);
+
+        // Copy of timingData is created to avoid concurrent modification of timingData map.
+        Map<String, Long> timingDataCopy = new HashMap<>();
+        for (Map.Entry<String, Long> entry : timingData.entrySet()) {
+            timingDataCopy.put(entry.getKey(), entry.getValue());
+        }
+        out.writeMap(timingDataCopy, StreamOutput::writeString, StreamOutput::writeLong);
+        out.writeString(sourceDescription);
+        targetNode.writeTo(out);
+    }
+
+    protected void validateAndSetStage(Stage expected, Stage next) {
+        if (stage != expected) {
+            assert false : "can't move replication to stage [" + next + "]. current stage: [" + stage + "] (expected [" + expected + "])";
+            throw new IllegalStateException(
+                "can't move replication to stage [" + next + "]. current stage: [" + stage + "] (expected [" + expected + "])"
+            );
+        }
+        stopTimersAndSetStage(next);
+    }
+
+    private void stopTimersAndSetStage(Stage next) {
+        // save the timing data for the current step
+        stageTimer.stop();
+        timingData.put(stage.name(), stageTimer.time());
+        // restart the step timer
+        stageTimer.reset();
+        stageTimer.start();
+        stage = next;
+    }
+
+    public void setStage(Stage stage) {
+        switch (stage) {
+            case INIT:
+                this.stage = Stage.INIT;
+                break;
+            case REPLICATING:
+                validateAndSetStage(Stage.INIT, stage);
+                // only start the overall timer once we've started replication
+                overallTimer.start();
+                break;
+            case GET_CHECKPOINT_INFO:
+                validateAndSetStage(Stage.REPLICATING, stage);
+                break;
+            case FILE_DIFF:
+                validateAndSetStage(Stage.GET_CHECKPOINT_INFO, stage);
+                break;
+            case GET_FILES:
+                validateAndSetStage(Stage.FILE_DIFF, stage);
+                break;
+            case FINALIZE_REPLICATION:
+                validateAndSetStage(Stage.GET_FILES, stage);
+                break;
+            case DONE:
+                validateAndSetStage(Stage.FINALIZE_REPLICATION, stage);
+                // add the overall timing data
+                overallTimer.stop();
+                timingData.put("OVERALL", overallTimer.time());
+                break;
+            default:
+                throw new IllegalArgumentException("unknown SegmentReplicationState.Stage [" + stage + "]");
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+
+        builder.field(Fields.INDEX_NAME, shardRouting.index().getName());
+        builder.field(Fields.ID, shardRouting.shardId().id());
+        builder.field(Fields.STAGE, getStage());
+        builder.timeField(Fields.START_TIME_IN_MILLIS, Fields.START_TIME, getTimer().startTime());
+        if (getTimer().stopTime() > 0) {
+            builder.timeField(Fields.STOP_TIME_IN_MILLIS, Fields.STOP_TIME, getTimer().stopTime());
+        }
+        builder.humanReadableField(Fields.TOTAL_TIME_IN_MILLIS, Fields.TOTAL_TIME, new TimeValue(getTimer().time()));
+        builder.field(Fields.SOURCE, getSourceDescription());
+
+        builder.startObject(Fields.TARGET);
+        builder.field(Fields.ID, targetNode.getId());
+        builder.field(Fields.HOST, targetNode.getHostName());
+        builder.field(Fields.TRANSPORT_ADDRESS, targetNode.getAddress().toString());
+        builder.field(Fields.IP, targetNode.getHostAddress());
+        builder.field(Fields.NAME, targetNode.getName());
+        builder.endObject();
+
+        builder.startObject(SegmentReplicationState.Fields.INDEX);
+        index.toXContent(builder, params);
+        builder.endObject();
+
+        builder.field(Fields.REPLICATING_STAGE, getReplicatingStageTime());
+        builder.field(Fields.GET_CHECKPOINT_INFO_STAGE, getGetCheckpointInfoStageTime());
+        builder.field(Fields.FILE_DIFF_STAGE, getFileDiffStageTime());
+        builder.field(Fields.GET_FILES_STAGE, getGetFileStageTime());
+        builder.field(Fields.FINALIZE_REPLICATION_STAGE, getFinalizeReplicationStageTime());
+
+        return builder;
+    }
+
+    static final class Fields {
+        static final String ID = "id";
+        static final String STAGE = "stage";
+        static final String START_TIME = "start_time";
+        static final String START_TIME_IN_MILLIS = "start_time_in_millis";
+        static final String STOP_TIME = "stop_time";
+        static final String STOP_TIME_IN_MILLIS = "stop_time_in_millis";
+        static final String TOTAL_TIME = "total_time";
+        static final String TOTAL_TIME_IN_MILLIS = "total_time_in_millis";
+        static final String SOURCE = "source";
+        static final String HOST = "host";
+        static final String TRANSPORT_ADDRESS = "transport_address";
+        static final String IP = "ip";
+        static final String NAME = "name";
+        static final String TARGET = "target";
+
+        static final String INDEX = "index";
+
+        static final String INDEX_NAME = "index_name";
+        static final String REPLICATING_STAGE = "replicating_stage";
+        static final String GET_CHECKPOINT_INFO_STAGE = "get_checkpoint_info_stage";
+        static final String FILE_DIFF_STAGE = "file_diff_stage";
+        static final String GET_FILES_STAGE = "get_files_stage";
+        static final String FINALIZE_REPLICATION_STAGE = "finalize_replication_stage";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTarget.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTarget.java
new file mode 100644
index 0000000000000..5ae480b7d63a4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTarget.java
@@ -0,0 +1,308 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.IndexFormatTooNewException;
+import org.apache.lucene.index.IndexFormatTooOldException;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.OpenSearchCorruptionException;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.StepListener;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.MultiFileWriter;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationTarget;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.List;
+import java.util.Locale;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Represents the target of a replication event.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationTarget extends ReplicationTarget {
+
+    private final ReplicationCheckpoint checkpoint;
+    private final SegmentReplicationSource source;
+    private final SegmentReplicationState state;
+    protected final MultiFileWriter multiFileWriter;
+
+    public final static String REPLICATION_PREFIX = "replication.";
+
+    public SegmentReplicationTarget(
+        IndexShard indexShard,
+        ReplicationCheckpoint checkpoint,
+        SegmentReplicationSource source,
+        ReplicationListener listener
+    ) {
+        super("replication_target", indexShard, new ReplicationLuceneIndex(), listener);
+        this.checkpoint = checkpoint;
+        this.source = source;
+        this.state = new SegmentReplicationState(
+            indexShard.routingEntry(),
+            stateIndex,
+            getId(),
+            source.getDescription(),
+            indexShard.recoveryState().getTargetNode()
+        );
+        this.multiFileWriter = new MultiFileWriter(indexShard.store(), stateIndex, getPrefix(), logger, this::ensureRefCount);
+    }
+
+    @Override
+    protected void closeInternal() {
+        try {
+            multiFileWriter.close();
+        } finally {
+            super.closeInternal();
+        }
+    }
+
+    @Override
+    protected String getPrefix() {
+        return REPLICATION_PREFIX + UUIDs.randomBase64UUID() + ".";
+    }
+
+    @Override
+    protected void onDone() {
+        state.setStage(SegmentReplicationState.Stage.DONE);
+    }
+
+    @Override
+    public SegmentReplicationState state() {
+        return state;
+    }
+
+    public SegmentReplicationTarget retryCopy() {
+        return new SegmentReplicationTarget(indexShard, checkpoint, source, listener);
+    }
+
+    @Override
+    public String description() {
+        return String.format(
+            Locale.ROOT,
+            "Id:[%d] Checkpoint [%s] Shard:[%s] Source:[%s]",
+            getId(),
+            getCheckpoint(),
+            shardId(),
+            source.getDescription()
+        );
+    }
+
+    @Override
+    public void notifyListener(ReplicationFailedException e, boolean sendShardFailure) {
+        listener.onFailure(state(), e, sendShardFailure);
+    }
+
+    @Override
+    public boolean reset(CancellableThreads newTargetCancellableThreads) throws IOException {
+        // TODO
+        return false;
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return this.checkpoint;
+    }
+
+    @Override
+    public void writeFileChunk(
+        StoreFileMetadata metadata,
+        long position,
+        BytesReference content,
+        boolean lastChunk,
+        int totalTranslogOps,
+        ActionListener<Void> listener
+    ) {
+        try {
+            multiFileWriter.writeFileChunk(metadata, position, content, lastChunk);
+            listener.onResponse(null);
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
+    /**
+     * Start the Replication event.
+     *
+     * @param listener {@link ActionListener} listener.
+     */
+    public void startReplication(ActionListener<Void> listener) {
+        cancellableThreads.setOnCancel((reason, beforeCancelEx) -> {
+            throw new CancellableThreads.ExecutionCancelledException("replication was canceled reason [" + reason + "]");
+        });
+        // TODO: Remove this useless state.
+        state.setStage(SegmentReplicationState.Stage.REPLICATING);
+        final StepListener<CheckpointInfoResponse> checkpointInfoListener = new StepListener<>();
+        final StepListener<GetSegmentFilesResponse> getFilesListener = new StepListener<>();
+
+        logger.trace(new ParameterizedMessage("Starting Replication Target: {}", description()));
+        // Get list of files to copy from this checkpoint.
+        state.setStage(SegmentReplicationState.Stage.GET_CHECKPOINT_INFO);
+        cancellableThreads.checkForCancel();
+        source.getCheckpointMetadata(getId(), checkpoint, checkpointInfoListener);
+
+        checkpointInfoListener.whenComplete(checkpointInfo -> {
+            final List<StoreFileMetadata> filesToFetch = getFiles(checkpointInfo);
+            state.setStage(SegmentReplicationState.Stage.GET_FILES);
+            cancellableThreads.checkForCancel();
+            source.getSegmentFiles(getId(), checkpointInfo.getCheckpoint(), filesToFetch, indexShard, getFilesListener);
+        }, listener::onFailure);
+
+        getFilesListener.whenComplete(response -> {
+            finalizeReplication(checkpointInfoListener.result());
+            listener.onResponse(null);
+        }, listener::onFailure);
+    }
+
+    private List<StoreFileMetadata> getFiles(CheckpointInfoResponse checkpointInfo) throws IOException {
+        cancellableThreads.checkForCancel();
+        state.setStage(SegmentReplicationState.Stage.FILE_DIFF);
+        final Store.RecoveryDiff diff = Store.segmentReplicationDiff(checkpointInfo.getMetadataMap(), indexShard.getSegmentMetadataMap());
+        // local files
+        final Set<String> localFiles = Set.of(indexShard.store().directory().listAll());
+        // set of local files that can be reused
+        final Set<String> reuseFiles = diff.missing.stream()
+            .filter(storeFileMetadata -> localFiles.contains(storeFileMetadata.name()))
+            .filter(this::validateLocalChecksum)
+            .map(StoreFileMetadata::name)
+            .collect(Collectors.toSet());
+
+        final List<StoreFileMetadata> missingFiles = diff.missing.stream()
+            .filter(md -> reuseFiles.contains(md.name()) == false)
+            .collect(Collectors.toList());
+
+        logger.trace(
+            () -> new ParameterizedMessage(
+                "Replication diff for checkpoint {} {} {}",
+                checkpointInfo.getCheckpoint(),
+                missingFiles,
+                diff.different
+            )
+        );
+        /*
+         * Segments are immutable. So if the replica has any segments with the same name that differ from the one in the incoming
+         * snapshot from source that means the local copy of the segment has been corrupted/changed in some way and we throw an
+         * IllegalStateException to fail the shard
+         */
+        if (diff.different.isEmpty() == false) {
+            throw new OpenSearchCorruptionException(
+                new ParameterizedMessage(
+                    "Shard {} has local copies of segments that differ from the primary {}",
+                    indexShard.shardId(),
+                    diff.different
+                ).getFormattedMessage()
+            );
+        }
+
+        for (StoreFileMetadata file : missingFiles) {
+            state.getIndex().addFileDetail(file.name(), file.length(), false);
+        }
+        return missingFiles;
+    }
+
+    private boolean validateLocalChecksum(StoreFileMetadata file) {
+        try (IndexInput indexInput = indexShard.store().directory().openInput(file.name(), IOContext.DEFAULT)) {
+            String checksum = Store.digestToString(CodecUtil.retrieveChecksum(indexInput));
+            if (file.checksum().equals(checksum)) {
+                return true;
+            } else {
+                // clear local copy with mismatch. Safe because file is not referenced by active reader.
+                store.deleteQuiet(file.name());
+                return false;
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException("Error reading " + file, e);
+        }
+    }
+
+    private void finalizeReplication(CheckpointInfoResponse checkpointInfoResponse) throws OpenSearchCorruptionException {
+        cancellableThreads.checkForCancel();
+        state.setStage(SegmentReplicationState.Stage.FINALIZE_REPLICATION);
+        // Handle empty SegmentInfos bytes for recovering replicas
+        if (checkpointInfoResponse.getInfosBytes() == null) {
+            return;
+        }
+        Store store = null;
+        try {
+            store = store();
+            store.incRef();
+            multiFileWriter.renameAllTempFiles();
+            final SegmentInfos infos = store.buildSegmentInfos(
+                checkpointInfoResponse.getInfosBytes(),
+                checkpointInfoResponse.getCheckpoint().getSegmentsGen()
+            );
+            indexShard.finalizeReplication(infos);
+        } catch (CorruptIndexException | IndexFormatTooNewException | IndexFormatTooOldException ex) {
+            // this is a fatal exception at this stage.
+            // this means we transferred files from the remote that have not be checksummed and they are
+            // broken. We have to clean up this shard entirely, remove all files and bubble it up to the
+            // source shard since this index might be broken there as well? The Source can handle this and checks
+            // its content on disk if possible.
+            try {
+                try {
+                    store.removeCorruptionMarker();
+                } finally {
+                    Lucene.cleanLuceneIndex(store.directory()); // clean up and delete all files
+                }
+            } catch (Exception e) {
+                logger.debug("Failed to clean lucene index", e);
+                ex.addSuppressed(e);
+            }
+            throw new OpenSearchCorruptionException(ex);
+        } catch (AlreadyClosedException ex) {
+            // In this case the shard is closed at some point while updating the reader.
+            // This can happen when the engine is closed in a separate thread.
+            logger.warn("Shard is already closed, closing replication");
+        } catch (OpenSearchException ex) {
+            /*
+             Ignore closed replication target as it can happen due to index shard closed event in a separate thread.
+             In such scenario, ignore the exception
+             */
+            assert cancellableThreads.isCancelled() : "Replication target closed but segment replication not cancelled";
+        } catch (Exception ex) {
+            throw new OpenSearchCorruptionException(ex);
+        } finally {
+            if (store != null) {
+                store.decRef();
+            }
+        }
+    }
+
+    /**
+     * Trigger a cancellation, this method will not close the target a subsequent call to #fail is required from target service.
+     */
+    @Override
+    public void cancel(String reason) {
+        if (finished.get() == false) {
+            logger.trace(new ParameterizedMessage("Cancelling replication for target {}", description()));
+            cancellableThreads.cancel(reason);
+            source.cancel();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTargetService.java b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTargetService.java
new file mode 100644
index 0000000000000..ffc4ab86661db
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTargetService.java
@@ -0,0 +1,625 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchCorruptionException;
+import org.opensearch.action.support.ChannelActionListener;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.shard.IndexEventListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardState;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.FileChunkRequest;
+import org.opensearch.indices.recovery.ForceSyncRequest;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RetryableTransportClient;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationCollection.ReplicationRef;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportChannel;
+import org.opensearch.transport.TransportRequestHandler;
+import org.opensearch.transport.TransportRequestOptions;
+import org.opensearch.transport.TransportService;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.opensearch.indices.replication.SegmentReplicationSourceService.Actions.UPDATE_VISIBLE_CHECKPOINT;
+
+/**
+ * Service class that orchestrates replication events on replicas.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationTargetService implements IndexEventListener {
+
+    private static final Logger logger = LogManager.getLogger(SegmentReplicationTargetService.class);
+
+    private final ThreadPool threadPool;
+    private final RecoverySettings recoverySettings;
+
+    private final ReplicationCollection<SegmentReplicationTarget> onGoingReplications;
+
+    private final Map<ShardId, SegmentReplicationTarget> completedReplications = ConcurrentCollections.newConcurrentMap();
+
+    private final SegmentReplicationSourceFactory sourceFactory;
+
+    protected final Map<ShardId, ReplicationCheckpoint> latestReceivedCheckpoint = ConcurrentCollections.newConcurrentMap();
+
+    private final IndicesService indicesService;
+    private final ClusterService clusterService;
+    private final TransportService transportService;
+
+    public ReplicationRef<SegmentReplicationTarget> get(long replicationId) {
+        return onGoingReplications.get(replicationId);
+    }
+
+    /**
+     * The internal actions
+     *
+     * @opensearch.internal
+     */
+    public static class Actions {
+        public static final String FILE_CHUNK = "internal:index/shard/replication/file_chunk";
+        public static final String FORCE_SYNC = "internal:index/shard/replication/segments_sync";
+    }
+
+    public SegmentReplicationTargetService(
+        final ThreadPool threadPool,
+        final RecoverySettings recoverySettings,
+        final TransportService transportService,
+        final SegmentReplicationSourceFactory sourceFactory,
+        final IndicesService indicesService,
+        final ClusterService clusterService
+    ) {
+        this(
+            threadPool,
+            recoverySettings,
+            transportService,
+            sourceFactory,
+            indicesService,
+            clusterService,
+            new ReplicationCollection<>(logger, threadPool)
+        );
+    }
+
+    public SegmentReplicationTargetService(
+        final ThreadPool threadPool,
+        final RecoverySettings recoverySettings,
+        final TransportService transportService,
+        final SegmentReplicationSourceFactory sourceFactory,
+        final IndicesService indicesService,
+        final ClusterService clusterService,
+        final ReplicationCollection<SegmentReplicationTarget> ongoingSegmentReplications
+    ) {
+        this.threadPool = threadPool;
+        this.recoverySettings = recoverySettings;
+        this.onGoingReplications = ongoingSegmentReplications;
+        this.sourceFactory = sourceFactory;
+        this.indicesService = indicesService;
+        this.clusterService = clusterService;
+        this.transportService = transportService;
+
+        transportService.registerRequestHandler(
+            Actions.FILE_CHUNK,
+            ThreadPool.Names.GENERIC,
+            FileChunkRequest::new,
+            new FileChunkTransportRequestHandler()
+        );
+        transportService.registerRequestHandler(
+            Actions.FORCE_SYNC,
+            ThreadPool.Names.GENERIC,
+            ForceSyncRequest::new,
+            new ForceSyncTransportRequestHandler()
+        );
+    }
+
+    /**
+     * Cancel any replications on this node for a replica that is about to be closed.
+     */
+    @Override
+    public void beforeIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {
+        if (indexShard != null && indexShard.indexSettings().isSegRepEnabled()) {
+            onGoingReplications.requestCancel(indexShard.shardId(), "Shard closing");
+            latestReceivedCheckpoint.remove(shardId);
+        }
+    }
+
+    /**
+     * Replay any received checkpoint while replica was recovering.  This does not need to happen
+     * for primary relocations because they recover from translog.
+     */
+    @Override
+    public void afterIndexShardStarted(IndexShard indexShard) {
+        if (indexShard.indexSettings().isSegRepEnabled() && indexShard.routingEntry().primary() == false) {
+            processLatestReceivedCheckpoint(indexShard, Thread.currentThread());
+        }
+    }
+
+    /**
+     * Cancel any replications on this node for a replica that has just been promoted as the new primary.
+     */
+    @Override
+    public void shardRoutingChanged(IndexShard indexShard, @Nullable ShardRouting oldRouting, ShardRouting newRouting) {
+        if (oldRouting != null && indexShard.indexSettings().isSegRepEnabled() && oldRouting.primary() == false && newRouting.primary()) {
+            onGoingReplications.requestCancel(indexShard.shardId(), "Shard has been promoted to primary");
+            latestReceivedCheckpoint.remove(indexShard.shardId());
+        }
+    }
+
+    /**
+     * returns SegmentReplicationState of on-going segment replication events.
+     */
+    @Nullable
+    public SegmentReplicationState getOngoingEventSegmentReplicationState(ShardId shardId) {
+        return Optional.ofNullable(onGoingReplications.getOngoingReplicationTarget(shardId))
+            .map(SegmentReplicationTarget::state)
+            .orElse(null);
+    }
+
+    /**
+     * returns SegmentReplicationState of latest completed segment replication events.
+     */
+    @Nullable
+    public SegmentReplicationState getlatestCompletedEventSegmentReplicationState(ShardId shardId) {
+        return Optional.ofNullable(completedReplications.get(shardId)).map(SegmentReplicationTarget::state).orElse(null);
+    }
+
+    /**
+     * returns SegmentReplicationState of on-going if present or completed segment replication events.
+     */
+    @Nullable
+    public SegmentReplicationState getSegmentReplicationState(ShardId shardId) {
+        return Optional.ofNullable(getOngoingEventSegmentReplicationState(shardId))
+            .orElseGet(() -> getlatestCompletedEventSegmentReplicationState(shardId));
+    }
+
+    /**
+     * Invoked when a new checkpoint is received from a primary shard.
+     * It checks if a new checkpoint should be processed or not and starts replication if needed.
+     *
+     * @param receivedCheckpoint received checkpoint that is checked for processing
+     * @param replicaShard       replica shard on which checkpoint is received
+     */
+    public synchronized void onNewCheckpoint(final ReplicationCheckpoint receivedCheckpoint, final IndexShard replicaShard) {
+        logger.debug(() -> new ParameterizedMessage("Replica received new replication checkpoint from primary [{}]", receivedCheckpoint));
+        // if the shard is in any state
+        if (replicaShard.state().equals(IndexShardState.CLOSED)) {
+            // ignore if shard is closed
+            logger.trace(() -> "Ignoring checkpoint, Shard is closed");
+            return;
+        }
+        updateLatestReceivedCheckpoint(receivedCheckpoint, replicaShard);
+        // Checks if replica shard is in the correct STARTED state to process checkpoints (avoids parallel replication events taking place)
+        // This check ensures we do not try to process a received checkpoint while the shard is still recovering, yet we stored the latest
+        // checkpoint to be replayed once the shard is Active.
+        if (replicaShard.state().equals(IndexShardState.STARTED) == true) {
+            // Checks if received checkpoint is already present and ahead then it replaces old received checkpoint
+            SegmentReplicationTarget ongoingReplicationTarget = onGoingReplications.getOngoingReplicationTarget(replicaShard.shardId());
+            if (ongoingReplicationTarget != null) {
+                if (ongoingReplicationTarget.getCheckpoint().getPrimaryTerm() < receivedCheckpoint.getPrimaryTerm()) {
+                    logger.debug(
+                        () -> new ParameterizedMessage(
+                            "Cancelling ongoing replication {} from old primary with primary term {}",
+                            ongoingReplicationTarget.description(),
+                            ongoingReplicationTarget.getCheckpoint().getPrimaryTerm()
+                        )
+                    );
+                    ongoingReplicationTarget.cancel("Cancelling stuck target after new primary");
+                } else {
+                    logger.debug(
+                        () -> new ParameterizedMessage(
+                            "Ignoring new replication checkpoint - shard is currently replicating to checkpoint {}",
+                            ongoingReplicationTarget.getCheckpoint()
+                        )
+                    );
+                    return;
+                }
+            }
+            final Thread thread = Thread.currentThread();
+            if (replicaShard.shouldProcessCheckpoint(receivedCheckpoint)) {
+                startReplication(replicaShard, receivedCheckpoint, new SegmentReplicationListener() {
+                    @Override
+                    public void onReplicationDone(SegmentReplicationState state) {
+                        logger.debug(
+                            () -> new ParameterizedMessage(
+                                "[shardId {}] [replication id {}] Replication complete to {}, timing data: {}",
+                                replicaShard.shardId().getId(),
+                                state.getReplicationId(),
+                                replicaShard.getLatestReplicationCheckpoint(),
+                                state.getTimingData()
+                            )
+                        );
+
+                        // update visible checkpoint to primary
+                        updateVisibleCheckpoint(state.getReplicationId(), replicaShard);
+
+                        // if we received a checkpoint during the copy event that is ahead of this
+                        // try and process it.
+                        processLatestReceivedCheckpoint(replicaShard, thread);
+                    }
+
+                    @Override
+                    public void onReplicationFailure(
+                        SegmentReplicationState state,
+                        ReplicationFailedException e,
+                        boolean sendShardFailure
+                    ) {
+                        logReplicationFailure(state, e, replicaShard);
+                        if (sendShardFailure == true) {
+                            failShard(e, replicaShard);
+                        } else {
+                            processLatestReceivedCheckpoint(replicaShard, thread);
+                        }
+                    }
+                });
+            }
+        } else {
+            logger.trace(
+                () -> new ParameterizedMessage("Ignoring checkpoint, shard not started {} {}", receivedCheckpoint, replicaShard.state())
+            );
+        }
+    }
+
+    private void logReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, IndexShard replicaShard) {
+        // only log as error if error is not a cancellation.
+        if (ExceptionsHelper.unwrap(e, CancellableThreads.ExecutionCancelledException.class) == null) {
+            logger.error(
+                () -> new ParameterizedMessage(
+                    "[shardId {}] [replication id {}] Replication failed, timing data: {}",
+                    replicaShard.shardId(),
+                    state.getReplicationId(),
+                    state.getTimingData()
+                ),
+                e
+            );
+        } else {
+            logger.debug(
+                () -> new ParameterizedMessage(
+                    "[shardId {}] [replication id {}] Replication cancelled",
+                    replicaShard.shardId(),
+                    state.getReplicationId()
+                ),
+                e
+            );
+        }
+    }
+
+    protected void updateVisibleCheckpoint(long replicationId, IndexShard replicaShard) {
+        // Update replication checkpoint on source via transport call only supported for remote store integration. For node-
+        // node communication, checkpoint update is piggy-backed to GET_SEGMENT_FILES transport call
+        if (replicaShard.indexSettings().isRemoteStoreEnabled() == false) {
+            return;
+        }
+        ShardRouting primaryShard = clusterService.state().routingTable().shardRoutingTable(replicaShard.shardId()).primaryShard();
+
+        final UpdateVisibleCheckpointRequest request = new UpdateVisibleCheckpointRequest(
+            replicationId,
+            replicaShard.routingEntry().allocationId().getId(),
+            primaryShard.shardId(),
+            getPrimaryNode(primaryShard),
+            replicaShard.getLatestReplicationCheckpoint()
+        );
+
+        final TransportRequestOptions options = TransportRequestOptions.builder()
+            .withTimeout(recoverySettings.internalActionTimeout())
+            .build();
+        logger.trace(
+            () -> new ParameterizedMessage(
+                "Updating Primary shard that replica {}-{} is synced to checkpoint {}",
+                replicaShard.shardId(),
+                replicaShard.routingEntry().allocationId(),
+                request.getCheckpoint()
+            )
+        );
+        RetryableTransportClient transportClient = new RetryableTransportClient(
+            transportService,
+            getPrimaryNode(primaryShard),
+            recoverySettings.internalActionRetryTimeout(),
+            logger
+        );
+        final ActionListener<Void> listener = new ActionListener<>() {
+            @Override
+            public void onResponse(Void unused) {
+                logger.trace(
+                    () -> new ParameterizedMessage(
+                        "Successfully updated replication checkpoint {} for replica {}",
+                        replicaShard.shardId(),
+                        request.getCheckpoint()
+                    )
+                );
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error(
+                    () -> new ParameterizedMessage(
+                        "Failed to update visible checkpoint for replica {}, {}:",
+                        replicaShard.shardId(),
+                        request.getCheckpoint()
+                    ),
+                    e
+                );
+            }
+        };
+
+        transportClient.executeRetryableAction(
+            UPDATE_VISIBLE_CHECKPOINT,
+            request,
+            options,
+            ActionListener.map(listener, r -> null),
+            in -> TransportResponse.Empty.INSTANCE
+        );
+    }
+
+    private DiscoveryNode getPrimaryNode(ShardRouting primaryShard) {
+        return clusterService.state().nodes().get(primaryShard.currentNodeId());
+    }
+
+    // visible to tests
+    protected boolean processLatestReceivedCheckpoint(IndexShard replicaShard, Thread thread) {
+        final ReplicationCheckpoint latestPublishedCheckpoint = latestReceivedCheckpoint.get(replicaShard.shardId());
+        if (latestPublishedCheckpoint != null && latestPublishedCheckpoint.isAheadOf(replicaShard.getLatestReplicationCheckpoint())) {
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "Processing latest received checkpoint for shard {} {}",
+                    replicaShard.shardId(),
+                    latestPublishedCheckpoint
+                )
+            );
+            Runnable runnable = () -> onNewCheckpoint(latestReceivedCheckpoint.get(replicaShard.shardId()), replicaShard);
+            // Checks if we are using same thread and forks if necessary.
+            if (thread == Thread.currentThread()) {
+                threadPool.generic().execute(runnable);
+            } else {
+                runnable.run();
+            }
+            return true;
+        }
+        return false;
+    }
+
+    // visible to tests
+    protected void updateLatestReceivedCheckpoint(ReplicationCheckpoint receivedCheckpoint, IndexShard replicaShard) {
+        if (latestReceivedCheckpoint.get(replicaShard.shardId()) != null) {
+            if (receivedCheckpoint.isAheadOf(latestReceivedCheckpoint.get(replicaShard.shardId()))) {
+                latestReceivedCheckpoint.replace(replicaShard.shardId(), receivedCheckpoint);
+            }
+        } else {
+            latestReceivedCheckpoint.put(replicaShard.shardId(), receivedCheckpoint);
+        }
+    }
+
+    /**
+     * Start a round of replication and sync to at least the given checkpoint.
+     * @param indexShard - {@link IndexShard} replica shard
+     * @param checkpoint - {@link ReplicationCheckpoint} checkpoint to sync to
+     * @param listener - {@link ReplicationListener}
+     * @return {@link SegmentReplicationTarget} target event orchestrating the event.
+     */
+    public SegmentReplicationTarget startReplication(
+        final IndexShard indexShard,
+        final ReplicationCheckpoint checkpoint,
+        final SegmentReplicationListener listener
+    ) {
+        final SegmentReplicationTarget target = new SegmentReplicationTarget(
+            indexShard,
+            checkpoint,
+            sourceFactory.get(indexShard),
+            listener
+        );
+        startReplication(target);
+        return target;
+    }
+
+    // pkg-private for integration tests
+    void startReplication(final SegmentReplicationTarget target) {
+        final long replicationId;
+        try {
+            replicationId = onGoingReplications.startSafe(target, recoverySettings.activityTimeout());
+        } catch (ReplicationFailedException e) {
+            // replication already running for shard.
+            target.fail(e, false);
+            return;
+        }
+        logger.trace(() -> new ParameterizedMessage("Added new replication to collection {}", target.description()));
+        threadPool.generic().execute(new ReplicationRunner(replicationId));
+    }
+
+    /**
+     * Listener that runs on changes in Replication state
+     *
+     * @opensearch.internal
+     */
+    public interface SegmentReplicationListener extends ReplicationListener {
+
+        @Override
+        default void onDone(ReplicationState state) {
+            onReplicationDone((SegmentReplicationState) state);
+        }
+
+        @Override
+        default void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+            onReplicationFailure((SegmentReplicationState) state, e, sendShardFailure);
+        }
+
+        void onReplicationDone(SegmentReplicationState state);
+
+        void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure);
+    }
+
+    /**
+     * Runnable implementation to trigger a replication event.
+     */
+    private class ReplicationRunner extends AbstractRunnable {
+
+        final long replicationId;
+
+        public ReplicationRunner(long replicationId) {
+            this.replicationId = replicationId;
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            try (final ReplicationRef<SegmentReplicationTarget> ref = onGoingReplications.get(replicationId)) {
+                logger.error(() -> new ParameterizedMessage("Error during segment replication, {}", ref.get().description()), e);
+            }
+            onGoingReplications.fail(replicationId, new ReplicationFailedException("Unexpected Error during replication", e), false);
+        }
+
+        @Override
+        public void doRun() {
+            start(replicationId);
+        }
+    }
+
+    private void start(final long replicationId) {
+        final SegmentReplicationTarget target;
+        try (ReplicationRef<SegmentReplicationTarget> replicationRef = onGoingReplications.get(replicationId)) {
+            // This check is for handling edge cases where the reference is removed before the ReplicationRunner is started by the
+            // threadpool.
+            if (replicationRef == null) {
+                return;
+            }
+            target = replicationRef.get();
+        }
+        target.startReplication(new ActionListener<>() {
+            @Override
+            public void onResponse(Void o) {
+                logger.debug(() -> new ParameterizedMessage("Finished replicating {} marking as done.", target.description()));
+                onGoingReplications.markAsDone(replicationId);
+                if (target.state().getIndex().recoveredFileCount() != 0 && target.state().getIndex().recoveredBytes() != 0) {
+                    completedReplications.put(target.shardId(), target);
+                }
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.debug("Replication failed {}", target.description());
+                if (e instanceof OpenSearchCorruptionException) {
+                    onGoingReplications.fail(replicationId, new ReplicationFailedException("Store corruption during replication", e), true);
+                    return;
+                }
+                onGoingReplications.fail(replicationId, new ReplicationFailedException("Segment Replication failed", e), false);
+            }
+        });
+    }
+
+    private class FileChunkTransportRequestHandler implements TransportRequestHandler<FileChunkRequest> {
+
+        // How many bytes we've copied since we last called RateLimiter.pause
+        final AtomicLong bytesSinceLastPause = new AtomicLong();
+
+        @Override
+        public void messageReceived(final FileChunkRequest request, TransportChannel channel, Task task) throws Exception {
+            try (ReplicationRef<SegmentReplicationTarget> ref = onGoingReplications.getSafe(request.recoveryId(), request.shardId())) {
+                final SegmentReplicationTarget target = ref.get();
+                final ActionListener<Void> listener = target.createOrFinishListener(channel, Actions.FILE_CHUNK, request);
+                target.handleFileChunk(request, target, bytesSinceLastPause, recoverySettings.rateLimiter(), listener);
+            }
+        }
+    }
+
+    /**
+     * Force sync transport handler forces round of segment replication. Caller should verify necessary checks before
+     * calling this handler.
+     */
+    private class ForceSyncTransportRequestHandler implements TransportRequestHandler<ForceSyncRequest> {
+        @Override
+        public void messageReceived(final ForceSyncRequest request, TransportChannel channel, Task task) throws Exception {
+            forceReplication(request, new ChannelActionListener<>(channel, Actions.FORCE_SYNC, request));
+        }
+    }
+
+    private void forceReplication(ForceSyncRequest request, ActionListener<TransportResponse> listener) {
+        final ShardId shardId = request.getShardId();
+        assert indicesService != null;
+        final IndexShard indexShard = indicesService.getShardOrNull(shardId);
+        // Proceed with round of segment replication only when it is allowed
+        if (indexShard == null || indexShard.getReplicationEngine().isEmpty()) {
+            listener.onResponse(TransportResponse.Empty.INSTANCE);
+        } else {
+            // We are skipping any validation for an incoming checkpoint, use the shard's latest checkpoint in the target.
+            startReplication(
+                indexShard,
+                indexShard.getLatestReplicationCheckpoint(),
+                new SegmentReplicationTargetService.SegmentReplicationListener() {
+                    @Override
+                    public void onReplicationDone(SegmentReplicationState state) {
+                        try {
+                            logger.trace(
+                                () -> new ParameterizedMessage(
+                                    "[shardId {}] [replication id {}] Force replication Sync complete to {}, timing data: {}",
+                                    shardId,
+                                    state.getReplicationId(),
+                                    indexShard.getLatestReplicationCheckpoint(),
+                                    state.getTimingData()
+                                )
+                            );
+                            // Promote engine type for primary target
+                            if (indexShard.recoveryState().getPrimary() == true) {
+                                indexShard.resetToWriteableEngine();
+                            } else {
+                                // Update the replica's checkpoint on primary's replication tracker.
+                                updateVisibleCheckpoint(state.getReplicationId(), indexShard);
+                            }
+                            listener.onResponse(TransportResponse.Empty.INSTANCE);
+                        } catch (Exception e) {
+                            logger.error("Error while marking replication completed", e);
+                            listener.onFailure(e);
+                        }
+                    }
+
+                    @Override
+                    public void onReplicationFailure(
+                        SegmentReplicationState state,
+                        ReplicationFailedException e,
+                        boolean sendShardFailure
+                    ) {
+                        logReplicationFailure(state, e, indexShard);
+                        if (sendShardFailure) {
+                            failShard(e, indexShard);
+                        }
+                        listener.onFailure(e);
+                    }
+                }
+            );
+        }
+    }
+
+    private void failShard(ReplicationFailedException e, IndexShard indexShard) {
+        try {
+            indexShard.failShard("unrecoverable replication failure", e);
+        } catch (Exception inner) {
+            logger.error("Error attempting to fail shard", inner);
+            e.addSuppressed(inner);
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/UpdateVisibleCheckpointRequest.java b/server/src/main/java/org/opensearch/indices/replication/UpdateVisibleCheckpointRequest.java
new file mode 100644
index 0000000000000..118643f1928f2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/UpdateVisibleCheckpointRequest.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.SegmentReplicationTransportRequest;
+
+import java.io.IOException;
+
+/**
+ * Request object for updating the replica's checkpoint on primary for tracking.
+ *
+ * @opensearch.internal
+ */
+public class UpdateVisibleCheckpointRequest extends SegmentReplicationTransportRequest {
+
+    private final ReplicationCheckpoint checkpoint;
+    private final ShardId primaryShardId;
+
+    public UpdateVisibleCheckpointRequest(StreamInput in) throws IOException {
+        super(in);
+        checkpoint = new ReplicationCheckpoint(in);
+        primaryShardId = new ShardId(in);
+    }
+
+    public UpdateVisibleCheckpointRequest(
+        long replicationId,
+        String targetAllocationId,
+        ShardId primaryShardId,
+        DiscoveryNode targetNode,
+        ReplicationCheckpoint checkpoint
+    ) {
+        super(replicationId, targetAllocationId, targetNode);
+        this.checkpoint = checkpoint;
+        this.primaryShardId = primaryShardId;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        checkpoint.writeTo(out);
+        primaryShardId.writeTo(out);
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return checkpoint;
+    }
+
+    public ShardId getPrimaryShardId() {
+        return primaryShardId;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointAction.java b/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointAction.java
new file mode 100644
index 0000000000000..11b01965c4af5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointAction.java
@@ -0,0 +1,207 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.checkpoint;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.action.support.replication.ReplicationResponse;
+import org.opensearch.action.support.replication.ReplicationTask;
+import org.opensearch.action.support.replication.TransportReplicationAction;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardClosedException;
+import org.opensearch.index.shard.ShardNotInPrimaryModeException;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.common.ReplicationTimer;
+import org.opensearch.node.NodeClosedException;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Replication action responsible for publishing checkpoint to a replica shard.
+ *
+ * @opensearch.internal
+ */
+
+public class PublishCheckpointAction extends TransportReplicationAction<
+    PublishCheckpointRequest,
+    PublishCheckpointRequest,
+    ReplicationResponse> {
+
+    public static final String ACTION_NAME = "indices:admin/publishCheckpoint";
+    protected static Logger logger = LogManager.getLogger(PublishCheckpointAction.class);
+
+    private final SegmentReplicationTargetService replicationService;
+
+    @Inject
+    public PublishCheckpointAction(
+        Settings settings,
+        TransportService transportService,
+        ClusterService clusterService,
+        IndicesService indicesService,
+        ThreadPool threadPool,
+        ShardStateAction shardStateAction,
+        ActionFilters actionFilters,
+        SegmentReplicationTargetService targetService
+    ) {
+        super(
+            settings,
+            ACTION_NAME,
+            transportService,
+            clusterService,
+            indicesService,
+            threadPool,
+            shardStateAction,
+            actionFilters,
+            PublishCheckpointRequest::new,
+            PublishCheckpointRequest::new,
+            ThreadPool.Names.REFRESH
+        );
+        this.replicationService = targetService;
+    }
+
+    @Override
+    protected ReplicationResponse newResponseInstance(StreamInput in) throws IOException {
+        return new ReplicationResponse(in);
+    }
+
+    @Override
+    protected void doExecute(Task task, PublishCheckpointRequest request, ActionListener<ReplicationResponse> listener) {
+        assert false : "use PublishCheckpointAction#publish";
+    }
+
+    @Override
+    public ReplicationMode getReplicationMode(IndexShard indexShard) {
+        if (indexShard.isRemoteTranslogEnabled()) {
+            return ReplicationMode.FULL_REPLICATION;
+        }
+        return super.getReplicationMode(indexShard);
+    }
+
+    /**
+     * Publish checkpoint request to shard
+     */
+    final void publish(IndexShard indexShard, ReplicationCheckpoint checkpoint) {
+        String primaryAllocationId = indexShard.routingEntry().allocationId().getId();
+        long primaryTerm = indexShard.getPendingPrimaryTerm();
+        final ThreadContext threadContext = threadPool.getThreadContext();
+        try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
+            // we have to execute under the system context so that if security is enabled the sync is authorized
+            threadContext.markAsSystemContext();
+            PublishCheckpointRequest request = new PublishCheckpointRequest(checkpoint);
+            final ReplicationTask task = (ReplicationTask) taskManager.register("transport", "segrep_publish_checkpoint", request);
+            final ReplicationTimer timer = new ReplicationTimer();
+            timer.start();
+            transportService.sendChildRequest(
+                indexShard.recoveryState().getTargetNode(),
+                transportPrimaryAction,
+                new ConcreteShardRequest<>(request, primaryAllocationId, primaryTerm),
+                task,
+                transportOptions,
+                new TransportResponseHandler<ReplicationResponse>() {
+                    @Override
+                    public ReplicationResponse read(StreamInput in) throws IOException {
+                        return newResponseInstance(in);
+                    }
+
+                    @Override
+                    public String executor() {
+                        return ThreadPool.Names.SAME;
+                    }
+
+                    @Override
+                    public void handleResponse(ReplicationResponse response) {
+                        timer.stop();
+                        logger.debug(
+                            () -> new ParameterizedMessage(
+                                "[shardId {}] Completed publishing checkpoint [{}], timing: {}",
+                                indexShard.shardId().getId(),
+                                checkpoint,
+                                timer.time()
+                            )
+                        );
+                        task.setPhase("finished");
+                        taskManager.unregister(task);
+                    }
+
+                    @Override
+                    public void handleException(TransportException e) {
+                        timer.stop();
+                        logger.debug("[shardId {}] Failed to publish checkpoint, timing: {}", indexShard.shardId().getId(), timer.time());
+                        task.setPhase("finished");
+                        taskManager.unregister(task);
+                        if (ExceptionsHelper.unwrap(
+                            e,
+                            NodeClosedException.class,
+                            IndexNotFoundException.class,
+                            AlreadyClosedException.class,
+                            IndexShardClosedException.class,
+                            ShardNotInPrimaryModeException.class
+                        ) != null) {
+                            // Node is shutting down or the index was deleted or the shard is closed
+                            return;
+                        }
+                        logger.warn(
+                            new ParameterizedMessage("{} segment replication checkpoint publishing failed", indexShard.shardId()),
+                            e
+                        );
+                    }
+                }
+            );
+            logger.trace(
+                () -> new ParameterizedMessage(
+                    "[shardId {}] Publishing replication checkpoint [{}]",
+                    checkpoint.getShardId().getId(),
+                    checkpoint
+                )
+            );
+        }
+    }
+
+    @Override
+    protected void shardOperationOnPrimary(
+        PublishCheckpointRequest request,
+        IndexShard primary,
+        ActionListener<PrimaryResult<PublishCheckpointRequest, ReplicationResponse>> listener
+    ) {
+        ActionListener.completeWith(listener, () -> new PrimaryResult<>(request, new ReplicationResponse()));
+    }
+
+    @Override
+    protected void shardOperationOnReplica(PublishCheckpointRequest request, IndexShard replica, ActionListener<ReplicaResult> listener) {
+        Objects.requireNonNull(request);
+        Objects.requireNonNull(replica);
+        ActionListener.completeWith(listener, () -> {
+            logger.trace(() -> new ParameterizedMessage("Checkpoint {} received on replica {}", request, replica.shardId()));
+            if (request.getCheckpoint().getShardId().equals(replica.shardId())) {
+                replicationService.onNewCheckpoint(request.getCheckpoint(), replica);
+            }
+            return new ReplicaResult();
+        });
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointRequest.java b/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointRequest.java
new file mode 100644
index 0000000000000..f9ad5733bee62
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointRequest.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.checkpoint;
+
+import org.opensearch.action.support.replication.ReplicationRequest;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Replication request responsible for publishing checkpoint request to a replica shard.
+ *
+ * @opensearch.internal
+ */
+public class PublishCheckpointRequest extends ReplicationRequest<PublishCheckpointRequest> {
+
+    private final ReplicationCheckpoint checkpoint;
+
+    public PublishCheckpointRequest(ReplicationCheckpoint checkpoint) {
+        super(checkpoint.getShardId());
+        this.checkpoint = checkpoint;
+    }
+
+    public PublishCheckpointRequest(StreamInput in) throws IOException {
+        super(in);
+        this.checkpoint = new ReplicationCheckpoint(in);
+    }
+
+    /**
+     * Returns Replication Checkpoint
+     */
+    public ReplicationCheckpoint getCheckpoint() {
+        return checkpoint;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        checkpoint.writeTo(out);
+    }
+
+    @Override
+    public String toString() {
+        return "PublishCheckpointRequest{" + "checkpoint=" + checkpoint + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/checkpoint/ReplicationCheckpoint.java b/server/src/main/java/org/opensearch/indices/replication/checkpoint/ReplicationCheckpoint.java
new file mode 100644
index 0000000000000..521522803c726
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/checkpoint/ReplicationCheckpoint.java
@@ -0,0 +1,215 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.checkpoint;
+
+import org.opensearch.Version;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.store.StoreFileMetadata;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Represents a Replication Checkpoint which is sent to a replica shard.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationCheckpoint implements Writeable, Comparable<ReplicationCheckpoint> {
+
+    private final ShardId shardId;
+    private final long primaryTerm;
+    private final long segmentsGen;
+    private final long segmentInfosVersion;
+    private final long length;
+    private final String codec;
+    private final Map<String, StoreFileMetadata> metadataMap;
+
+    public static ReplicationCheckpoint empty(ShardId shardId) {
+        return empty(shardId, "");
+    }
+
+    public static ReplicationCheckpoint empty(ShardId shardId, String codec) {
+        return new ReplicationCheckpoint(shardId, codec);
+    }
+
+    private ReplicationCheckpoint(ShardId shardId, String codec) {
+        this.shardId = shardId;
+        primaryTerm = SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
+        segmentsGen = SequenceNumbers.NO_OPS_PERFORMED;
+        segmentInfosVersion = SequenceNumbers.NO_OPS_PERFORMED;
+        length = 0L;
+        this.codec = codec;
+        this.metadataMap = Collections.emptyMap();
+    }
+
+    public ReplicationCheckpoint(ShardId shardId, long primaryTerm, long segmentsGen, long segmentInfosVersion, String codec) {
+        this(shardId, primaryTerm, segmentsGen, segmentInfosVersion, 0L, codec, Collections.emptyMap());
+    }
+
+    public ReplicationCheckpoint(
+        ShardId shardId,
+        long primaryTerm,
+        long segmentsGen,
+        long segmentInfosVersion,
+        long length,
+        String codec,
+        Map<String, StoreFileMetadata> metadataMap
+    ) {
+        this.shardId = shardId;
+        this.primaryTerm = primaryTerm;
+        this.segmentsGen = segmentsGen;
+        this.segmentInfosVersion = segmentInfosVersion;
+        this.length = length;
+        this.codec = codec;
+        this.metadataMap = metadataMap;
+    }
+
+    public ReplicationCheckpoint(StreamInput in) throws IOException {
+        shardId = new ShardId(in);
+        primaryTerm = in.readLong();
+        segmentsGen = in.readLong();
+        segmentInfosVersion = in.readLong();
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            length = in.readLong();
+            codec = in.readString();
+        } else {
+            length = 0L;
+            codec = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            this.metadataMap = in.readMap(StreamInput::readString, StoreFileMetadata::new);
+        } else {
+            this.metadataMap = Collections.emptyMap();
+        }
+    }
+
+    /**
+     * The primary term of this Replication Checkpoint.
+     *
+     * @return the primary term
+     */
+    public long getPrimaryTerm() {
+        return primaryTerm;
+    }
+
+    /**
+     * @return the Segments Gen number
+     */
+    public long getSegmentsGen() {
+        return segmentsGen;
+    }
+
+    /**
+     * @return the Segment Info version
+     */
+    public long getSegmentInfosVersion() {
+        return segmentInfosVersion;
+    }
+
+    /**
+     * Shard Id of primary shard.
+     *
+     * @return the Shard Id
+     */
+    public ShardId getShardId() {
+        return shardId;
+    }
+
+    /**
+     * @return The size in bytes of this checkpoint.
+     */
+    public long getLength() {
+        return length;
+    }
+
+    /**
+     * Latest supported codec version
+     *
+         * @return the codec name
+     */
+    public String getCodec() {
+        return codec;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        shardId.writeTo(out);
+        out.writeLong(primaryTerm);
+        out.writeLong(segmentsGen);
+        out.writeLong(segmentInfosVersion);
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeLong(length);
+            out.writeString(codec);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeMap(metadataMap, StreamOutput::writeString, (valueOut, fc) -> fc.writeTo(valueOut));
+        }
+    }
+
+    @Override
+    public int compareTo(ReplicationCheckpoint other) {
+        return this.isAheadOf(other) ? -1 : 1;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ReplicationCheckpoint that = (ReplicationCheckpoint) o;
+        return primaryTerm == that.primaryTerm
+            && segmentsGen == that.segmentsGen
+            && segmentInfosVersion == that.segmentInfosVersion
+            && Objects.equals(shardId, that.shardId)
+            && codec.equals(that.codec);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(shardId, primaryTerm, segmentsGen);
+    }
+
+    /**
+     * Checks if current replication checkpoint is AheadOf `other` replication checkpoint point by first comparing
+     * primaryTerm followed by segmentInfosVersion. Returns true when `other` is null.
+     */
+    public boolean isAheadOf(@Nullable ReplicationCheckpoint other) {
+        return other == null
+            || primaryTerm > other.getPrimaryTerm()
+            || (primaryTerm == other.getPrimaryTerm() && segmentInfosVersion > other.getSegmentInfosVersion());
+    }
+
+    public Map<String, StoreFileMetadata> getMetadataMap() {
+        return metadataMap;
+    }
+
+    @Override
+    public String toString() {
+        return "ReplicationCheckpoint{"
+            + "shardId="
+            + shardId
+            + ", primaryTerm="
+            + primaryTerm
+            + ", segmentsGen="
+            + segmentsGen
+            + ", version="
+            + segmentInfosVersion
+            + ", size="
+            + length
+            + ", codec="
+            + codec
+            + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/checkpoint/SegmentReplicationCheckpointPublisher.java b/server/src/main/java/org/opensearch/indices/replication/checkpoint/SegmentReplicationCheckpointPublisher.java
new file mode 100644
index 0000000000000..b4bcdc92e539a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/checkpoint/SegmentReplicationCheckpointPublisher.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.checkpoint;
+
+import org.opensearch.common.inject.Inject;
+import org.opensearch.index.shard.IndexShard;
+
+import java.util.Objects;
+
+/**
+ * Publish Segment Replication Checkpoint.
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationCheckpointPublisher {
+
+    private final PublishAction publishAction;
+
+    // This Component is behind feature flag so we are manually binding this in IndicesModule.
+    @Inject
+    public SegmentReplicationCheckpointPublisher(PublishCheckpointAction publishAction) {
+        this(publishAction::publish);
+    }
+
+    public SegmentReplicationCheckpointPublisher(PublishAction publishAction) {
+        this.publishAction = Objects.requireNonNull(publishAction);
+    }
+
+    public void publish(IndexShard indexShard, ReplicationCheckpoint checkpoint) {
+        publishAction.publish(indexShard, checkpoint);
+        indexShard.onCheckpointPublished(checkpoint);
+    }
+
+    /**
+     * Represents an action that is invoked to publish segment replication checkpoint to replica shard
+     */
+    public interface PublishAction {
+        void publish(IndexShard indexShard, ReplicationCheckpoint checkpoint);
+    }
+
+    /**
+     * NoOp Checkpoint publisher
+     */
+    public static final SegmentReplicationCheckpointPublisher EMPTY = new SegmentReplicationCheckpointPublisher(
+        (indexShard, checkpoint) -> {}
+    );
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/checkpoint/package-info.java b/server/src/main/java/org/opensearch/indices/replication/checkpoint/package-info.java
new file mode 100644
index 0000000000000..a30154ea9206a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/checkpoint/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package containing classes to implement a replication checkpoint */
+package org.opensearch.indices.replication.checkpoint;
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/CopyState.java b/server/src/main/java/org/opensearch/indices/replication/common/CopyState.java
new file mode 100644
index 0000000000000..3b7ae2af80ca0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/CopyState.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.ByteBuffersDataOutput;
+import org.apache.lucene.store.ByteBuffersIndexOutput;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.util.concurrent.AbstractRefCounted;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Map;
+
+/**
+ * An Opensearch-specific version of Lucene's CopyState class that
+ * holds incRef'd file level details for one point-in-time segment infos.
+ *
+ * @opensearch.internal
+ */
+public class CopyState extends AbstractRefCounted {
+
+    private final GatedCloseable<SegmentInfos> segmentInfosRef;
+    /** ReplicationCheckpoint requested */
+    private final ReplicationCheckpoint requestedReplicationCheckpoint;
+    /** Actual ReplicationCheckpoint returned by the shard */
+    private final ReplicationCheckpoint replicationCheckpoint;
+    private final Map<String, StoreFileMetadata> metadataMap;
+    private final byte[] infosBytes;
+    private final IndexShard shard;
+
+    public CopyState(ReplicationCheckpoint requestedReplicationCheckpoint, IndexShard shard) throws IOException {
+        super("CopyState-" + shard.shardId());
+        this.requestedReplicationCheckpoint = requestedReplicationCheckpoint;
+        this.shard = shard;
+        final Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> latestSegmentInfosAndCheckpoint = shard
+            .getLatestSegmentInfosAndCheckpoint();
+        this.segmentInfosRef = latestSegmentInfosAndCheckpoint.v1();
+        this.replicationCheckpoint = latestSegmentInfosAndCheckpoint.v2();
+        SegmentInfos segmentInfos = this.segmentInfosRef.get();
+        this.metadataMap = shard.store().getSegmentMetadataMap(segmentInfos);
+
+        ByteBuffersDataOutput buffer = new ByteBuffersDataOutput();
+        // resource description and name are not used, but resource description cannot be null
+        try (ByteBuffersIndexOutput indexOutput = new ByteBuffersIndexOutput(buffer, "", null)) {
+            segmentInfos.write(indexOutput);
+        }
+        this.infosBytes = buffer.toArrayCopy();
+    }
+
+    @Override
+    protected void closeInternal() {
+        try {
+            segmentInfosRef.close();
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    public ReplicationCheckpoint getCheckpoint() {
+        return replicationCheckpoint;
+    }
+
+    public Map<String, StoreFileMetadata> getMetadataMap() {
+        return metadataMap;
+    }
+
+    public byte[] getInfosBytes() {
+        return infosBytes;
+    }
+
+    public IndexShard getShard() {
+        return shard;
+    }
+
+    public ReplicationCheckpoint getRequestedReplicationCheckpoint() {
+        return requestedReplicationCheckpoint;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationCollection.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationCollection.java
new file mode 100644
index 0000000000000..4950b5da2915f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationCollection.java
@@ -0,0 +1,347 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.concurrent.AutoCloseableRefCounted;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardClosedException;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.ConcurrentMap;
+import java.util.stream.Collectors;
+
+/**
+ * This class holds a collection of all on going replication events on the current node (i.e., the node is the target node
+ * of those events). The class is used to guarantee concurrent semantics such that once an event was done/cancelled/failed
+ * no other thread will be able to find it. Last, the {@link ReplicationRef} inner class verifies that temporary files
+ * and store will only be cleared once on going usage is finished.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationCollection<T extends ReplicationTarget> {
+
+    /** This is the single source of truth for ongoing target events. If it's not here, it was canceled or done */
+    private final ConcurrentMap<Long, T> onGoingTargetEvents = ConcurrentCollections.newConcurrentMap();
+
+    private final Logger logger;
+    private final ThreadPool threadPool;
+
+    public ReplicationCollection(Logger logger, ThreadPool threadPool) {
+        this.logger = logger;
+        this.threadPool = threadPool;
+    }
+
+    /**
+     * Starts a new target event for a given shard, fails the given target if this shard is already replicating.
+     * @param target ReplicationTarget to start
+     * @param activityTimeout timeout for entire replication event
+     * @return The replication id
+     */
+    public long startSafe(T target, TimeValue activityTimeout) {
+        synchronized (onGoingTargetEvents) {
+            final boolean isPresent = onGoingTargetEvents.values()
+                .stream()
+                .map(ReplicationTarget::shardId)
+                .anyMatch(t -> t.equals(target.shardId()));
+            if (isPresent) {
+                throw new ReplicationFailedException("Shard " + target.shardId() + " is already replicating");
+            } else {
+                return start(target, activityTimeout);
+            }
+        }
+    }
+
+    /**
+     * Starts a new target event for the given shard, source node and state
+     *
+     * @return the id of the new target event.
+     */
+    public long start(T target, TimeValue activityTimeout) {
+        startInternal(target, activityTimeout);
+        return target.getId();
+    }
+
+    private void startInternal(T target, TimeValue activityTimeout) {
+        T existingTarget = onGoingTargetEvents.putIfAbsent(target.getId(), target);
+        assert existingTarget == null : "found two Target instances with the same id";
+        logger.trace("started {}", target.description());
+        threadPool.schedule(
+            new ReplicationMonitor(target.getId(), target.lastAccessTime(), activityTimeout),
+            activityTimeout,
+            ThreadPool.Names.GENERIC
+        );
+    }
+
+    /**
+     * Resets the target event and performs a restart on the current index shard
+     *
+     * @see IndexShard#performRecoveryRestart()
+     * @return newly created Target
+     */
+    @SuppressWarnings(value = "unchecked")
+    public T reset(final long id, final TimeValue activityTimeout) {
+        T oldTarget = null;
+        final T newTarget;
+
+        try {
+            synchronized (onGoingTargetEvents) {
+                // swap targets in a synchronized block to ensure that the newly added target is picked up by
+                // cancelForShard whenever the old target is picked up
+                oldTarget = onGoingTargetEvents.remove(id);
+                if (oldTarget == null) {
+                    return null;
+                }
+
+                newTarget = (T) oldTarget.retryCopy();
+                startInternal(newTarget, activityTimeout);
+            }
+
+            // Closes the current target
+            boolean successfulReset = oldTarget.reset(newTarget.cancellableThreads());
+            if (successfulReset) {
+                logger.trace("restarted {}, previous id [{}]", newTarget.description(), oldTarget.getId());
+                return newTarget;
+            } else {
+                logger.trace(
+                    "{} could not be reset as it is already cancelled, previous id [{}]",
+                    newTarget.description(),
+                    oldTarget.getId()
+                );
+                cancel(newTarget.getId(), "cancelled during reset");
+                return null;
+            }
+        } catch (Exception e) {
+            // fail shard to be safe
+            assert oldTarget != null;
+            oldTarget.notifyListener(new ReplicationFailedException("Unable to reset target", e), true);
+            return null;
+        }
+    }
+
+    public T getTarget(long id) {
+        return onGoingTargetEvents.get(id);
+    }
+
+    /**
+     * gets the {@link ReplicationTarget } for a given id. The ShardTarget returned has it's ref count already incremented
+     * to make sure it's safe to use. However, you must call {@link ReplicationTarget#decRef()} when you are done with it, typically
+     * by using this method in a try-with-resources clause.
+     * <p>
+     * Returns null if target event is not found
+     */
+    public ReplicationRef<T> get(long id) {
+        T status = onGoingTargetEvents.get(id);
+        if (status != null && status.tryIncRef()) {
+            return new ReplicationRef<T>(status);
+        }
+        return null;
+    }
+
+    /** Similar to {@link #get(long)} but throws an exception if no target is found */
+    public ReplicationRef<T> getSafe(long id, ShardId shardId) {
+        ReplicationRef<T> ref = get(id);
+        if (ref == null) {
+            throw new IndexShardClosedException(shardId);
+        }
+        assert ref.get().indexShard().shardId().equals(shardId);
+        return ref;
+    }
+
+    /** cancel the target with the given id (if found) and remove it from the target collection */
+    public boolean cancel(long id, String reason) {
+        T removed = onGoingTargetEvents.remove(id);
+        boolean cancelled = false;
+        if (removed != null) {
+            logger.trace("canceled {} (reason [{}])", removed.description(), reason);
+            removed.cancel(reason);
+            cancelled = true;
+        }
+        return cancelled;
+    }
+
+    /**
+     * fail the target with the given id (if found) and remove it from the target collection
+     *
+     * @param id               id of the target to fail
+     * @param e                exception with reason for the failure
+     * @param sendShardFailure true a shard failed message should be sent to the master
+     */
+    public void fail(long id, ReplicationFailedException e, boolean sendShardFailure) {
+        T removed = onGoingTargetEvents.remove(id);
+        if (removed != null) {
+            logger.trace("failing {}. Send shard failure: [{}]", removed.description(), sendShardFailure);
+            removed.fail(e, sendShardFailure);
+        }
+    }
+
+    /** mark the target with the given id as done (if found) */
+    public void markAsDone(long id) {
+        T removed = onGoingTargetEvents.remove(id);
+        if (removed != null) {
+            logger.trace("Marking {} as done", removed.description());
+            removed.markAsDone();
+        }
+    }
+
+    /** the number of ongoing target events */
+    public int size() {
+        return onGoingTargetEvents.size();
+    }
+
+    /**
+     * cancel all ongoing targets for the given shard
+     *
+     * @param reason       reason for cancellation
+     * @param shardId      shardId for which to cancel targets
+     * @return true if a target was cancelled
+     */
+    public boolean cancelForShard(ShardId shardId, String reason) {
+        boolean cancelled = false;
+        List<T> matchedTargets = new ArrayList<>();
+        synchronized (onGoingTargetEvents) {
+            for (Iterator<T> it = onGoingTargetEvents.values().iterator(); it.hasNext();) {
+                T status = it.next();
+                if (status.indexShard().shardId().equals(shardId)) {
+                    matchedTargets.add(status);
+                    it.remove();
+                }
+            }
+        }
+        for (T removed : matchedTargets) {
+            logger.trace("canceled {} (reason [{}])", removed.description(), reason);
+            removed.cancel(reason);
+            cancelled = true;
+        }
+        return cancelled;
+    }
+
+    /**
+     * Trigger cancel on the target but do not remove it from the collection.
+     * This is intended to be called to ensure replication events are removed from the collection
+     * only when the target has closed.
+     *
+     * @param shardId {@link ShardId} shard events to cancel
+     * @param reason {@link String} reason for cancellation
+     */
+    public void requestCancel(ShardId shardId, String reason) {
+        for (T value : onGoingTargetEvents.values()) {
+            if (value.shardId().equals(shardId)) {
+                value.cancel(reason);
+            }
+        }
+    }
+
+    /**
+     * Get target for shard
+     *
+     * @param shardId      shardId
+     * @return ReplicationTarget for input shardId
+     */
+    public T getOngoingReplicationTarget(ShardId shardId) {
+        final List<T> replicationTargetList = onGoingTargetEvents.values()
+            .stream()
+            .filter(t -> t.indexShard.shardId().equals(shardId))
+            .collect(Collectors.toList());
+        assert replicationTargetList.size() <= 1 : "More than one on-going replication targets";
+        return replicationTargetList.size() > 0 ? replicationTargetList.get(0) : null;
+    }
+
+    /**
+     * a reference to {@link ReplicationTarget}, which implements {@link AutoCloseable}. closing the reference
+     * causes {@link ReplicationTarget#decRef()} to be called. This makes sure that the underlying resources
+     * will not be freed until {@link ReplicationRef#close()} is called.
+     *
+     * @opensearch.internal
+     */
+    public static class ReplicationRef<T extends ReplicationTarget> extends AutoCloseableRefCounted<T> {
+
+        /**
+         * Important: {@link ReplicationTarget#tryIncRef()} should
+         * be *successfully* called on status before
+         */
+        public ReplicationRef(T status) {
+            super(status);
+            status.setLastAccessTime();
+        }
+    }
+
+    private class ReplicationMonitor extends AbstractRunnable {
+        private final long id;
+        private final TimeValue checkInterval;
+
+        private volatile long lastSeenAccessTime;
+
+        private ReplicationMonitor(long id, long lastSeenAccessTime, TimeValue checkInterval) {
+            this.id = id;
+            this.checkInterval = checkInterval;
+            this.lastSeenAccessTime = lastSeenAccessTime;
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            logger.error(() -> new ParameterizedMessage("unexpected error while monitoring [{}]", id), e);
+        }
+
+        @Override
+        protected void doRun() throws Exception {
+            T status = onGoingTargetEvents.get(id);
+            if (status == null) {
+                logger.trace("[monitor] no status found for [{}], shutting down", id);
+                return;
+            }
+            long accessTime = status.lastAccessTime();
+            if (accessTime == lastSeenAccessTime) {
+                String message = "no activity after [" + checkInterval + "]";
+                fail(
+                    id,
+                    new ReplicationFailedException(message),
+                    true // to be safe, we don't know what go stuck
+                );
+                return;
+            }
+            lastSeenAccessTime = accessTime;
+            logger.trace("[monitor] rescheduling check for [{}]. last access time is [{}]", id, lastSeenAccessTime);
+            threadPool.schedule(this, checkInterval, ThreadPool.Names.GENERIC);
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationFailedException.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationFailedException.java
new file mode 100644
index 0000000000000..47c327baba303
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationFailedException.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+
+import java.io.IOException;
+
+/**
+ * Exception thrown if replication fails
+ *
+ * @opensearch.internal
+ */
+public class ReplicationFailedException extends OpenSearchException {
+
+    public ReplicationFailedException(IndexShard shard, Throwable cause) {
+        this(shard, null, cause);
+    }
+
+    public ReplicationFailedException(IndexShard shard, @Nullable String extraInfo, Throwable cause) {
+        this(shard.shardId(), extraInfo, cause);
+    }
+
+    public ReplicationFailedException(ShardId shardId, @Nullable String extraInfo, Throwable cause) {
+        super(shardId + ": Replication failed on " + (extraInfo == null ? "" : " (" + extraInfo + ")"), cause);
+    }
+
+    public ReplicationFailedException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    public ReplicationFailedException(Exception e) {
+        super(e);
+    }
+
+    public ReplicationFailedException(String msg) {
+        super(msg);
+    }
+
+    public ReplicationFailedException(String msg, Throwable cause) {
+        super(msg, cause);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationListener.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationListener.java
new file mode 100644
index 0000000000000..1d3c48d084f60
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationListener.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+/**
+ * Interface for listeners that run when there's a change in {@link ReplicationState}
+ *
+ * @opensearch.internal
+ */
+public interface ReplicationListener {
+
+    void onDone(ReplicationState state);
+
+    void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure);
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationLuceneIndex.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationLuceneIndex.java
new file mode 100644
index 0000000000000..02be9d04a95a6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationLuceneIndex.java
@@ -0,0 +1,529 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.store.StoreStats;
+import org.opensearch.indices.recovery.RecoveryState;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+/**
+ * Represents the Lucene Index (set of files on a single shard) involved
+ * in the replication process.
+ *
+ * @opensearch.internal
+ */
+public final class ReplicationLuceneIndex extends ReplicationTimer implements ToXContentFragment, Writeable {
+    private final FilesDetails filesDetails;
+
+    public static final long UNKNOWN = -1L;
+
+    private long sourceThrottlingInNanos = UNKNOWN;
+    private long targetThrottleTimeInNanos = UNKNOWN;
+
+    public ReplicationLuceneIndex() {
+        this(new FilesDetails());
+    }
+
+    public ReplicationLuceneIndex(FilesDetails filesDetails) {
+        this.filesDetails = filesDetails;
+    }
+
+    public ReplicationLuceneIndex(StreamInput in) throws IOException {
+        super(in);
+        filesDetails = new FilesDetails(in);
+        sourceThrottlingInNanos = in.readLong();
+        targetThrottleTimeInNanos = in.readLong();
+    }
+
+    @Override
+    public synchronized void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        filesDetails.writeTo(out);
+        out.writeLong(sourceThrottlingInNanos);
+        out.writeLong(targetThrottleTimeInNanos);
+    }
+
+    public synchronized List<FileMetadata> fileDetails() {
+        return Collections.unmodifiableList(new ArrayList<>(filesDetails.values()));
+    }
+
+    public synchronized void reset() {
+        super.reset();
+        filesDetails.clear();
+        sourceThrottlingInNanos = UNKNOWN;
+        targetThrottleTimeInNanos = UNKNOWN;
+    }
+
+    public synchronized void addFileDetail(String name, long length, boolean reused) {
+        filesDetails.addFileDetails(name, length, reused);
+    }
+
+    public synchronized void setFileDetailsComplete() {
+        filesDetails.setComplete();
+    }
+
+    public synchronized void addRecoveredBytesToFile(String name, long bytes) {
+        filesDetails.addRecoveredBytesToFile(name, bytes);
+    }
+
+    public synchronized void addSourceThrottling(long timeInNanos) {
+        if (sourceThrottlingInNanos == UNKNOWN) {
+            sourceThrottlingInNanos = timeInNanos;
+        } else {
+            sourceThrottlingInNanos += timeInNanos;
+        }
+    }
+
+    public synchronized void addTargetThrottling(long timeInNanos) {
+        if (targetThrottleTimeInNanos == UNKNOWN) {
+            targetThrottleTimeInNanos = timeInNanos;
+        } else {
+            targetThrottleTimeInNanos += timeInNanos;
+        }
+    }
+
+    public synchronized TimeValue sourceThrottling() {
+        return TimeValue.timeValueNanos(sourceThrottlingInNanos);
+    }
+
+    public synchronized TimeValue targetThrottling() {
+        return TimeValue.timeValueNanos(targetThrottleTimeInNanos);
+    }
+
+    /**
+     * total number of files that are part of this recovery, both re-used and recovered
+     */
+    public synchronized int totalFileCount() {
+        return filesDetails.size();
+    }
+
+    /**
+     * total number of files to be recovered (potentially not yet done)
+     */
+    public synchronized int totalRecoverFiles() {
+        int total = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused() == false) {
+                total++;
+            }
+        }
+        return total;
+    }
+
+    /**
+     * number of file that were recovered (excluding on ongoing files)
+     */
+    public synchronized int recoveredFileCount() {
+        int count = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.fullyRecovered()) {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    /**
+     * percent of recovered (i.e., not reused) files out of the total files to be recovered
+     */
+    public synchronized float recoveredFilesPercent() {
+        int total = 0;
+        int recovered = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused() == false) {
+                total++;
+                if (file.fullyRecovered()) {
+                    recovered++;
+                }
+            }
+        }
+        if (total == 0 && filesDetails.size() == 0) {      // indicates we are still in init phase
+            return 0.0f;
+        }
+        if (total == recovered) {
+            return 100.0f;
+        } else {
+            float result = 100.0f * (recovered / (float) total);
+            return result;
+        }
+    }
+
+    /**
+     * total number of bytes in th shard
+     */
+    public synchronized long totalBytes() {
+        long total = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            total += file.length();
+        }
+        return total;
+    }
+
+    /**
+     * total number of bytes recovered so far, including both existing and reused
+     */
+    public synchronized long recoveredBytes() {
+        long recovered = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            recovered += file.recovered();
+        }
+        return recovered;
+    }
+
+    /**
+     * total bytes of files to be recovered (potentially not yet done)
+     */
+    public synchronized long totalRecoverBytes() {
+        long total = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused() == false) {
+                total += file.length();
+            }
+        }
+        return total;
+    }
+
+    /**
+     * @return number of bytes still to recover, i.e. {@link ReplicationLuceneIndex#totalRecoverBytes()} minus {@link ReplicationLuceneIndex#recoveredBytes()}, or
+     * {@code -1} if the full set of files to recover is not yet known
+     */
+    public synchronized long bytesStillToRecover() {
+        if (filesDetails.isComplete() == false) {
+            return -1L;
+        }
+        long total = 0L;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused() == false) {
+                total += file.length() - file.recovered();
+            }
+        }
+        return total;
+    }
+
+    /**
+     * percent of bytes recovered out of total files bytes *to be* recovered
+     */
+    public synchronized float recoveredBytesPercent() {
+        long total = 0;
+        long recovered = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused() == false) {
+                total += file.length();
+                recovered += file.recovered();
+            }
+        }
+        if (total == 0 && filesDetails.size() == 0) {
+            // indicates we are still in init phase
+            return 0.0f;
+        }
+        if (total == recovered) {
+            return 100.0f;
+        } else {
+            return 100.0f * recovered / total;
+        }
+    }
+
+    public synchronized int reusedFileCount() {
+        int reused = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused()) {
+                reused++;
+            }
+        }
+        return reused;
+    }
+
+    public synchronized long reusedBytes() {
+        long reused = 0;
+        for (FileMetadata file : filesDetails.values()) {
+            if (file.reused()) {
+                reused += file.length();
+            }
+        }
+        return reused;
+    }
+
+    @Override
+    public synchronized XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        // stream size first, as it matters more and the files section can be long
+        builder.startObject(Fields.SIZE);
+        builder.humanReadableField(Fields.TOTAL_IN_BYTES, Fields.TOTAL, new ByteSizeValue(totalBytes()));
+        builder.humanReadableField(Fields.REUSED_IN_BYTES, Fields.REUSED, new ByteSizeValue(reusedBytes()));
+        builder.humanReadableField(Fields.RECOVERED_IN_BYTES, Fields.RECOVERED, new ByteSizeValue(recoveredBytes()));
+        builder.field(Fields.PERCENT, String.format(Locale.ROOT, "%1.1f%%", recoveredBytesPercent()));
+        builder.endObject();
+
+        builder.startObject(Fields.FILES);
+        builder.field(Fields.TOTAL, totalFileCount());
+        builder.field(Fields.REUSED, reusedFileCount());
+        builder.field(Fields.RECOVERED, recoveredFileCount());
+        builder.field(Fields.PERCENT, String.format(Locale.ROOT, "%1.1f%%", recoveredFilesPercent()));
+        filesDetails.toXContent(builder, params);
+        builder.endObject();
+        builder.humanReadableField(Fields.TOTAL_TIME_IN_MILLIS, Fields.TOTAL_TIME, new TimeValue(time()));
+        builder.humanReadableField(Fields.SOURCE_THROTTLE_TIME_IN_MILLIS, Fields.SOURCE_THROTTLE_TIME, sourceThrottling());
+        builder.humanReadableField(Fields.TARGET_THROTTLE_TIME_IN_MILLIS, Fields.TARGET_THROTTLE_TIME, targetThrottling());
+        return builder;
+    }
+
+    @Override
+    public synchronized String toString() {
+        try {
+            XContentBuilder builder = XContentFactory.jsonBuilder().prettyPrint();
+            builder.startObject();
+            toXContent(builder, EMPTY_PARAMS);
+            builder.endObject();
+            return builder.toString();
+        } catch (IOException e) {
+            return "{ \"error\" : \"" + e.getMessage() + "\"}";
+        }
+    }
+
+    public synchronized FileMetadata getFileDetails(String dest) {
+        return filesDetails.get(dest);
+    }
+
+    private static final class FilesDetails implements ToXContentFragment, Writeable {
+        protected final Map<String, FileMetadata> fileMetadataMap = new HashMap<>();
+        protected boolean complete;
+
+        public FilesDetails() {}
+
+        FilesDetails(StreamInput in) throws IOException {
+            int size = in.readVInt();
+            for (int i = 0; i < size; i++) {
+                FileMetadata file = new FileMetadata(in);
+                fileMetadataMap.put(file.name, file);
+            }
+            if (in.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
+                complete = in.readBoolean();
+            } else {
+                // This flag is used by disk-based allocation to decide whether the remaining bytes measurement is accurate or not; if not
+                // then it falls back on an estimate. There's only a very short window in which the file details are present but incomplete
+                // so this is a reasonable approximation, and the stats reported to the disk-based allocator don't hit this code path
+                // anyway since they always use IndexShard#getRecoveryState which is never transported over the wire.
+                complete = fileMetadataMap.isEmpty() == false;
+            }
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            final FileMetadata[] files = values().toArray(new FileMetadata[0]);
+            out.writeVInt(files.length);
+            for (FileMetadata file : files) {
+                file.writeTo(out);
+            }
+            if (out.getVersion().onOrAfter(StoreStats.RESERVED_BYTES_VERSION)) {
+                out.writeBoolean(complete);
+            }
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            if (params.paramAsBoolean("detailed", false)) {
+                builder.startArray(Fields.DETAILS);
+                for (FileMetadata file : values()) {
+                    file.toXContent(builder, params);
+                }
+                builder.endArray();
+            }
+
+            return builder;
+        }
+
+        public void addFileDetails(String name, long length, boolean reused) {
+            assert complete == false : "addFileDetail for [" + name + "] when file details are already complete";
+            FileMetadata existing = fileMetadataMap.put(name, new FileMetadata(name, length, reused));
+            assert existing == null : "file [" + name + "] is already reported";
+        }
+
+        public void addRecoveredBytesToFile(String name, long bytes) {
+            FileMetadata file = fileMetadataMap.get(name);
+            assert file != null : "file [" + name + "] hasn't been reported";
+            file.addRecoveredBytes(bytes);
+        }
+
+        public FileMetadata get(String name) {
+            return fileMetadataMap.get(name);
+        }
+
+        public void setComplete() {
+            complete = true;
+        }
+
+        public int size() {
+            return fileMetadataMap.size();
+        }
+
+        public boolean isEmpty() {
+            return fileMetadataMap.isEmpty();
+        }
+
+        public void clear() {
+            fileMetadataMap.clear();
+            complete = false;
+        }
+
+        public Collection<FileMetadata> values() {
+            return fileMetadataMap.values();
+        }
+
+        public boolean isComplete() {
+            return complete;
+        }
+    }
+
+    /**
+     * Metadata about a file
+     *
+     * @opensearch.internal
+     */
+    public static final class FileMetadata implements ToXContentObject, Writeable {
+        private String name;
+        private long length;
+        private long recovered;
+        private boolean reused;
+
+        public FileMetadata(String name, long length, boolean reused) {
+            assert name != null;
+            this.name = name;
+            this.length = length;
+            this.reused = reused;
+        }
+
+        public FileMetadata(StreamInput in) throws IOException {
+            name = in.readString();
+            length = in.readVLong();
+            recovered = in.readVLong();
+            reused = in.readBoolean();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(name);
+            out.writeVLong(length);
+            out.writeVLong(recovered);
+            out.writeBoolean(reused);
+        }
+
+        public void addRecoveredBytes(long bytes) {
+            assert reused == false : "file is marked as reused, can't update recovered bytes";
+            assert bytes >= 0 : "can't recovered negative bytes. got [" + bytes + "]";
+            recovered += bytes;
+        }
+
+        /**
+         * file name
+         */
+        public String name() {
+            return name;
+        }
+
+        /**
+         * file length
+         */
+        public long length() {
+            return length;
+        }
+
+        /**
+         * number of bytes recovered for this file (so far). 0 if the file is reused
+         */
+        public long recovered() {
+            return recovered;
+        }
+
+        /**
+         * returns true if the file is reused from a local copy
+         */
+        public boolean reused() {
+            return reused;
+        }
+
+        public boolean fullyRecovered() {
+            return reused == false && length == recovered;
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            builder.field(Fields.NAME, name);
+            builder.humanReadableField(Fields.LENGTH_IN_BYTES, Fields.LENGTH, new ByteSizeValue(length));
+            builder.field(Fields.REUSED, reused);
+            builder.humanReadableField(Fields.RECOVERED_IN_BYTES, Fields.RECOVERED, new ByteSizeValue(recovered));
+            builder.endObject();
+            return builder;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof FileMetadata) {
+                FileMetadata other = (FileMetadata) obj;
+                return name.equals(other.name) && length == other.length() && reused == other.reused() && recovered == other.recovered();
+            }
+            return false;
+        }
+
+        @Override
+        public int hashCode() {
+            int result = name.hashCode();
+            result = 31 * result + Long.hashCode(length);
+            result = 31 * result + Long.hashCode(recovered);
+            result = 31 * result + (reused ? 1 : 0);
+            return result;
+        }
+
+        @Override
+        public String toString() {
+            return "file (name [" + name + "], reused [" + reused + "], length [" + length + "], recovered [" + recovered + "])";
+        }
+    }
+
+    /**
+     * Duplicates many of Field names in {@link RecoveryState}
+     */
+    static final class Fields {
+        static final String TOTAL_TIME = "total_time";
+        static final String TOTAL_TIME_IN_MILLIS = "total_time_in_millis";
+        static final String NAME = "name";
+        static final String RECOVERED = "recovered";
+        static final String RECOVERED_IN_BYTES = "recovered_in_bytes";
+        static final String LENGTH = "length";
+        static final String LENGTH_IN_BYTES = "length_in_bytes";
+        static final String FILES = "files";
+        static final String TOTAL = "total";
+        static final String TOTAL_IN_BYTES = "total_in_bytes";
+        static final String REUSED = "reused";
+        static final String REUSED_IN_BYTES = "reused_in_bytes";
+        static final String PERCENT = "percent";
+        static final String DETAILS = "details";
+        static final String SIZE = "size";
+        static final String SOURCE_THROTTLE_TIME = "source_throttle_time";
+        static final String SOURCE_THROTTLE_TIME_IN_MILLIS = "source_throttle_time_in_millis";
+        static final String TARGET_THROTTLE_TIME = "target_throttle_time";
+        static final String TARGET_THROTTLE_TIME_IN_MILLIS = "target_throttle_time_in_millis";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationRequestTracker.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationRequestTracker.java
new file mode 100644
index 0000000000000..39649727e31d7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationRequestTracker.java
@@ -0,0 +1,98 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.common.Nullable;
+import org.opensearch.common.util.concurrent.ListenableFuture;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
+
+/**
+ * Tracks replication requests
+ *
+ * @opensearch.internal
+ */
+public class ReplicationRequestTracker {
+
+    private final Map<Long, ListenableFuture<Void>> ongoingRequests = Collections.synchronizedMap(new HashMap<>());
+    private final LocalCheckpointTracker checkpointTracker = new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED);
+
+    /**
+     * This method will mark that a request with a unique sequence number has been received. If this is the
+     * first time the unique request has been received, this method will return a listener to be completed.
+     * The caller should then perform the requested action and complete the returned listener.
+     *
+     *
+     * If the unique request has already been received, this method will either complete the provided listener
+     * or attach that listener to the listener returned in the first call. In this case, the method will
+     * return null and the caller should not perform the requested action as a prior caller is already
+     * performing the action.
+     */
+    @Nullable
+    public synchronized ActionListener<Void> markReceivedAndCreateListener(long requestSeqNo, ActionListener<Void> listener) {
+        if (checkpointTracker.hasProcessed(requestSeqNo)) {
+            final ListenableFuture<Void> existingFuture = ongoingRequests.get(requestSeqNo);
+            if (existingFuture != null) {
+                existingFuture.addListener(listener, OpenSearchExecutors.newDirectExecutorService());
+            } else {
+                listener.onResponse(null);
+            }
+            return null;
+        } else {
+            checkpointTracker.markSeqNoAsProcessed(requestSeqNo);
+            final ListenableFuture<Void> future = new ListenableFuture<>();
+            ongoingRequests.put(requestSeqNo, future);
+            future.addListener(new ActionListener<Void>() {
+                @Override
+                public void onResponse(Void v) {
+                    ongoingRequests.remove(requestSeqNo);
+                    listener.onResponse(v);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    // We do not remove the future to cache the error for retried requests
+                    listener.onFailure(e);
+                }
+            }, OpenSearchExecutors.newDirectExecutorService());
+            return future;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationState.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationState.java
new file mode 100644
index 0000000000000..029fcb6a3b690
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationState.java
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+/**
+ * Represents a state object used to track copying of segments from an external source
+ *
+ * @opensearch.internal
+ */
+public interface ReplicationState {
+    ReplicationLuceneIndex getIndex();
+
+    ReplicationTimer getTimer();
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTarget.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTarget.java
new file mode 100644
index 0000000000000..4606d878052f7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTarget.java
@@ -0,0 +1,283 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.RateLimiter;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.support.ChannelActionListener;
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.AbstractRefCounted;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.FileChunkRequest;
+import org.opensearch.indices.recovery.RecoveryTransportRequest;
+import org.opensearch.transport.TransportChannel;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Represents the target of a replication operation performed on a shard
+ *
+ * @opensearch.internal
+ */
+public abstract class ReplicationTarget extends AbstractRefCounted {
+
+    private static final AtomicLong ID_GENERATOR = new AtomicLong();
+
+    // last time the target/status was accessed
+    private volatile long lastAccessTime = System.nanoTime();
+    private final ReplicationRequestTracker requestTracker = new ReplicationRequestTracker();
+    private final long id;
+
+    protected final AtomicBoolean finished = new AtomicBoolean();
+    protected final IndexShard indexShard;
+    protected final Store store;
+    protected final ReplicationListener listener;
+    protected final Logger logger;
+    protected final CancellableThreads cancellableThreads;
+    protected final ReplicationLuceneIndex stateIndex;
+
+    protected abstract String getPrefix();
+
+    protected abstract void onDone();
+
+    protected void onCancel(String reason) {
+        cancellableThreads.cancel(reason);
+    }
+
+    public abstract ReplicationState state();
+
+    public abstract ReplicationTarget retryCopy();
+
+    public abstract String description();
+
+    public ReplicationListener getListener() {
+        return listener;
+    }
+
+    public CancellableThreads cancellableThreads() {
+        return cancellableThreads;
+    }
+
+    public abstract void notifyListener(ReplicationFailedException e, boolean sendShardFailure);
+
+    public ReplicationTarget(String name, IndexShard indexShard, ReplicationLuceneIndex stateIndex, ReplicationListener listener) {
+        super(name);
+        this.logger = Loggers.getLogger(getClass(), indexShard.shardId());
+        this.listener = listener;
+        this.id = ID_GENERATOR.incrementAndGet();
+        this.stateIndex = stateIndex;
+        this.indexShard = indexShard;
+        this.store = indexShard.store();
+        // make sure the store is not released until we are done.
+        this.cancellableThreads = new CancellableThreads();
+        store.incRef();
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public abstract boolean reset(CancellableThreads newTargetCancellableThreads) throws IOException;
+
+    /**
+     * return the last time this ReplicationStatus was used (based on System.nanoTime()
+     */
+    public long lastAccessTime() {
+        return lastAccessTime;
+    }
+
+    /**
+     * sets the lasAccessTime flag to now
+     */
+    public void setLastAccessTime() {
+        lastAccessTime = System.nanoTime();
+    }
+
+    @Nullable
+    public ActionListener<Void> markRequestReceivedAndCreateListener(long requestSeqNo, ActionListener<Void> listener) {
+        return requestTracker.markReceivedAndCreateListener(requestSeqNo, listener);
+    }
+
+    public IndexShard indexShard() {
+        ensureRefCount();
+        return indexShard;
+    }
+
+    public Store store() {
+        ensureRefCount();
+        return store;
+    }
+
+    public ShardId shardId() {
+        return indexShard.shardId();
+    }
+
+    /**
+     * mark the current replication as done
+     */
+    public void markAsDone() {
+        if (finished.compareAndSet(false, true)) {
+            try {
+                onDone();
+            } finally {
+                // release the initial reference. replication files will be cleaned as soon as ref count goes to zero, potentially now
+                decRef();
+            }
+            listener.onDone(state());
+        }
+    }
+
+    /**
+     * cancel the replication. calling this method will clean temporary files and release the store
+     * unless this object is in use (in which case it will be cleaned once all ongoing users call
+     * {@link #decRef()}
+     */
+    public void cancel(String reason) {
+        if (finished.compareAndSet(false, true)) {
+            try {
+                logger.debug("replication cancelled (reason: [{}])", reason);
+                onCancel(reason);
+            } finally {
+                // release the initial reference. replication files will be cleaned as soon as ref count goes to zero, potentially now
+                decRef();
+            }
+        }
+    }
+
+    /**
+     * fail the replication and call listener
+     *
+     * @param e                exception that encapsulates the failure
+     * @param sendShardFailure indicates whether to notify the master of the shard failure
+     */
+    public void fail(ReplicationFailedException e, boolean sendShardFailure) {
+        if (finished.compareAndSet(false, true)) {
+            try {
+                logger.debug("marking target " + description() + " as failed", e);
+                notifyListener(e, sendShardFailure);
+            } finally {
+                try {
+                    cancellableThreads.cancel("failed" + description() + "[" + ExceptionsHelper.stackTrace(e) + "]");
+                } finally {
+                    // release the initial reference. replication files will be cleaned as soon as ref count goes to zero, potentially now
+                    decRef();
+                }
+            }
+        }
+    }
+
+    protected void ensureRefCount() {
+        if (refCount() <= 0) {
+            throw new OpenSearchException(
+                "ReplicationTarget is used but it's refcount is 0. Probably a mismatch between incRef/decRef calls"
+            );
+        }
+    }
+
+    @Nullable
+    public ActionListener<Void> createOrFinishListener(
+        final TransportChannel channel,
+        final String action,
+        final RecoveryTransportRequest request
+    ) {
+        return createOrFinishListener(channel, action, request, nullVal -> TransportResponse.Empty.INSTANCE);
+    }
+
+    @Nullable
+    public ActionListener<Void> createOrFinishListener(
+        final TransportChannel channel,
+        final String action,
+        final RecoveryTransportRequest request,
+        final CheckedFunction<Void, TransportResponse, Exception> responseFn
+    ) {
+        final ActionListener<TransportResponse> channelListener = new ChannelActionListener<>(channel, action, request);
+        final ActionListener<Void> voidListener = ActionListener.map(channelListener, responseFn);
+
+        final long requestSeqNo = request.requestSeqNo();
+        final ActionListener<Void> listener;
+        if (requestSeqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
+            listener = markRequestReceivedAndCreateListener(requestSeqNo, voidListener);
+        } else {
+            listener = voidListener;
+        }
+
+        return listener;
+    }
+
+    /**
+     * Handle a FileChunkRequest for a {@link ReplicationTarget}.
+     *
+     * @param request {@link FileChunkRequest} Request containing the file chunk.
+     * @param bytesSinceLastPause {@link AtomicLong} Bytes since the last pause.
+     * @param rateLimiter {@link RateLimiter} Rate limiter.
+     * @param listener {@link ActionListener} listener that completes when the chunk has been written.
+     * @throws IOException When there is an issue pausing the rate limiter.
+     */
+    public void handleFileChunk(
+        final FileChunkRequest request,
+        final ReplicationTarget replicationTarget,
+        final AtomicLong bytesSinceLastPause,
+        final RateLimiter rateLimiter,
+        final ActionListener<Void> listener
+    ) throws IOException {
+
+        if (listener == null) {
+            return;
+        }
+        final ReplicationLuceneIndex indexState = replicationTarget.state().getIndex();
+        if (request.sourceThrottleTimeInNanos() != ReplicationLuceneIndex.UNKNOWN) {
+            indexState.addSourceThrottling(request.sourceThrottleTimeInNanos());
+        }
+        if (rateLimiter != null) {
+            long bytes = bytesSinceLastPause.addAndGet(request.content().length());
+            if (bytes > rateLimiter.getMinPauseCheckBytes()) {
+                // Time to pause
+                bytesSinceLastPause.addAndGet(-bytes);
+                long throttleTimeInNanos = rateLimiter.pause(bytes);
+                indexState.addTargetThrottling(throttleTimeInNanos);
+                replicationTarget.indexShard().recoveryStats().addThrottleTime(throttleTimeInNanos);
+            }
+        }
+        writeFileChunk(
+            request.metadata(),
+            request.position(),
+            request.content(),
+            request.lastChunk(),
+            request.totalTranslogOps(),
+            listener
+        );
+    }
+
+    public abstract void writeFileChunk(
+        StoreFileMetadata metadata,
+        long position,
+        BytesReference content,
+        boolean lastChunk,
+        int totalTranslogOps,
+        ActionListener<Void> listener
+    );
+
+    protected void closeInternal() {
+        store.decRef();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTimer.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTimer.java
new file mode 100644
index 0000000000000..aeb9ef29f4a52
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationTimer.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+
+/**
+ * A serializable timer that is used to measure the time taken for
+ * file replication operations like recovery.
+ *
+ * @opensearch.internal
+ */
+public class ReplicationTimer implements Writeable {
+    private long startTime = 0;
+    private long startNanoTime = 0;
+    private long time = -1;
+    private long stopTime = 0;
+
+    public ReplicationTimer() {}
+
+    public ReplicationTimer(StreamInput in) throws IOException {
+        startTime = in.readVLong();
+        startNanoTime = in.readVLong();
+        stopTime = in.readVLong();
+        time = in.readVLong();
+    }
+
+    @Override
+    public synchronized void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(startTime);
+        out.writeVLong(startNanoTime);
+        out.writeVLong(stopTime);
+        // write a snapshot of current time, which is not per se the time field
+        out.writeVLong(time());
+    }
+
+    public synchronized void start() {
+        assert startTime == 0 : "already started";
+        startTime = System.currentTimeMillis();
+        startNanoTime = System.nanoTime();
+    }
+
+    /**
+     * Returns start time in millis
+     */
+    public synchronized long startTime() {
+        return startTime;
+    }
+
+    /**
+     * Returns elapsed time in millis, or 0 if timer was not started
+     */
+    public synchronized long time() {
+        if (startNanoTime == 0) {
+            return 0;
+        }
+        if (time >= 0) {
+            return time;
+        }
+        return Math.max(0, TimeValue.nsecToMSec(System.nanoTime() - startNanoTime));
+    }
+
+    /**
+     * Returns stop time in millis
+     */
+    public synchronized long stopTime() {
+        return stopTime;
+    }
+
+    public synchronized void stop() {
+        assert stopTime == 0 : "already stopped";
+        stopTime = Math.max(System.currentTimeMillis(), startTime);
+        time = TimeValue.nsecToMSec(System.nanoTime() - startNanoTime);
+        assert time >= 0;
+    }
+
+    public synchronized void reset() {
+        startTime = 0;
+        startNanoTime = 0;
+        time = -1;
+        stopTime = 0;
+    }
+
+    // only used in tests
+    public long getStartNanoTime() {
+        return startNanoTime;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/ReplicationType.java b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationType.java
new file mode 100644
index 0000000000000..ac4840e390c0b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/ReplicationType.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+/**
+ * Enumerates the types of replication strategies supported by OpenSearch.
+ * For more information, see https://github.com/opensearch-project/OpenSearch/issues/1694
+ *
+ * @opensearch.internal
+ */
+public enum ReplicationType {
+
+    DOCUMENT,
+    SEGMENT;
+
+    public static ReplicationType parseString(String replicationType) {
+        try {
+            return ReplicationType.valueOf(replicationType);
+        } catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException("Could not parse ReplicationStrategy for [" + replicationType + "]");
+        } catch (NullPointerException npe) {
+            // return a default value for null input
+            return DOCUMENT;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationLagTimer.java b/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationLagTimer.java
new file mode 100644
index 0000000000000..c97edba72da0d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationLagTimer.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+
+import java.io.IOException;
+
+/**
+ * Wrapper class for Replication Timer which also tracks time elapsed since the timer was created.
+ * Currently, this is being used to calculate
+ * 1. Replication Lag: Total time taken by replica to sync after primary refreshed.
+ * 2. Replication event time: Total time taken by replica to sync after primary published the checkpoint
+ *                     (excludes the time spent by primary for uploading the segments to remote store).
+ *
+ * @opensearch.internal
+ */
+public class SegmentReplicationLagTimer extends ReplicationTimer {
+    private long creationTime;
+
+    public SegmentReplicationLagTimer() {
+        super();
+        creationTime = System.nanoTime();
+    }
+
+    public SegmentReplicationLagTimer(StreamInput in) throws IOException {
+        super(in);
+        creationTime = in.readVLong();
+    }
+
+    @Override
+    public synchronized void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeVLong(creationTime);
+    }
+
+    public long totalElapsedTime() {
+        return TimeValue.nsecToMSec(Math.max(System.nanoTime() - creationTime, 0));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationTransportRequest.java b/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationTransportRequest.java
new file mode 100644
index 0000000000000..667009d2b7479
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/SegmentReplicationTransportRequest.java
@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+
+/**
+ * Abstract base class for transport-layer requests related to segment replication.
+ *
+ * @opensearch.internal
+ */
+public abstract class SegmentReplicationTransportRequest extends TransportRequest {
+
+    private final long replicationId;
+    private final String targetAllocationId;
+    private final DiscoveryNode targetNode;
+
+    protected SegmentReplicationTransportRequest(long replicationId, String targetAllocationId, DiscoveryNode targetNode) {
+        this.replicationId = replicationId;
+        this.targetAllocationId = targetAllocationId;
+        this.targetNode = targetNode;
+    }
+
+    protected SegmentReplicationTransportRequest(StreamInput in) throws IOException {
+        super(in);
+        this.replicationId = in.readLong();
+        this.targetAllocationId = in.readString();
+        this.targetNode = new DiscoveryNode(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeLong(this.replicationId);
+        out.writeString(this.targetAllocationId);
+        targetNode.writeTo(out);
+    }
+
+    public long getReplicationId() {
+        return replicationId;
+    }
+
+    public String getTargetAllocationId() {
+        return targetAllocationId;
+    }
+
+    public DiscoveryNode getTargetNode() {
+        return targetNode;
+    }
+
+    @Override
+    public String toString() {
+        return "SegmentReplicationTransportRequest{"
+            + "replicationId="
+            + replicationId
+            + ", targetAllocationId='"
+            + targetAllocationId
+            + '\''
+            + ", targetNode="
+            + targetNode
+            + '}';
+    }
+}
diff --git a/server/src/main/java/org/opensearch/indices/replication/common/package-info.java b/server/src/main/java/org/opensearch/indices/replication/common/package-info.java
new file mode 100644
index 0000000000000..77a8422f83829
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/common/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Foundation classes for Replication Implementation. */
+package org.opensearch.indices.replication.common;
diff --git a/server/src/main/java/org/opensearch/indices/replication/package-info.java b/server/src/main/java/org/opensearch/indices/replication/package-info.java
new file mode 100644
index 0000000000000..270f8b820f7b3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/replication/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Document vs Segment Replication classes. */
+package org.opensearch.indices.replication;
diff --git a/server/src/main/java/org/opensearch/indices/store/IndicesStore.java b/server/src/main/java/org/opensearch/indices/store/IndicesStore.java
index ef10bae987bb1..1efaca09204da 100644
--- a/server/src/main/java/org/opensearch/indices/store/IndicesStore.java
+++ b/server/src/main/java/org/opensearch/indices/store/IndicesStore.java
@@ -50,18 +50,19 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
@@ -69,7 +70,6 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -83,6 +83,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Store for multiple indexes
+ *
+ * @opensearch.internal
+ */
 public class IndicesStore implements ClusterStateListener, Closeable {
 
     private static final Logger logger = LogManager.getLogger(IndicesStore.class);
@@ -447,6 +452,11 @@ private IndexShard getShard(ShardActiveRequest request) {
 
     }
 
+    /**
+     * A shard active request
+     *
+     * @opensearch.internal
+     */
     private static class ShardActiveRequest extends TransportRequest {
         protected TimeValue timeout = null;
         private ClusterName clusterName;
@@ -478,6 +488,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * The shard active response
+     *
+     * @opensearch.internal
+     */
     private static class ShardActiveResponse extends TransportResponse {
 
         private final boolean shardActive;
diff --git a/server/src/main/java/org/opensearch/indices/store/TransportNodesListShardStoreMetadata.java b/server/src/main/java/org/opensearch/indices/store/TransportNodesListShardStoreMetadata.java
index d385b2e6aa74e..d456985757177 100644
--- a/server/src/main/java/org/opensearch/indices/store/TransportNodesListShardStoreMetadata.java
+++ b/server/src/main/java/org/opensearch/indices/store/TransportNodesListShardStoreMetadata.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.support.ActionFilters;
@@ -50,11 +49,13 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.gateway.AsyncShardFetch;
 import org.opensearch.index.IndexService;
@@ -62,7 +63,6 @@
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLease;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
@@ -77,6 +77,11 @@
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Metadata for shard stores from a list of transport nodes
+ *
+ * @opensearch.internal
+ */
 public class TransportNodesListShardStoreMetadata extends TransportNodesAction<
     TransportNodesListShardStoreMetadata.Request,
     TransportNodesListShardStoreMetadata.NodesStoreFilesMetadata,
@@ -203,8 +208,8 @@ private StoreFilesMetadata listStoreMetadata(NodeRequest request) throws IOExcep
                 return new StoreFilesMetadata(shardId, Store.MetadataSnapshot.EMPTY, Collections.emptyList());
             }
             // note that this may fail if it can't get access to the shard lock. Since we check above there is an active shard, this means:
-            // 1) a shard is being constructed, which means the master will not use a copy of this replica
-            // 2) A shard is shutting down and has not cleared it's content within lock timeout. In this case the master may not
+            // 1) a shard is being constructed, which means the cluster-manager will not use a copy of this replica
+            // 2) A shard is shutting down and has not cleared it's content within lock timeout. In this case the cluster-manager may not
             // reuse local resources.
             final Store.MetadataSnapshot metadataSnapshot = Store.readMetadataSnapshot(
                 shardPath.resolveIndex(),
@@ -225,6 +230,11 @@ private StoreFilesMetadata listStoreMetadata(NodeRequest request) throws IOExcep
         }
     }
 
+    /**
+     * Metadata for store files
+     *
+     * @opensearch.internal
+     */
     public static class StoreFilesMetadata implements Iterable<StoreFileMetadata>, Writeable {
         private final ShardId shardId;
         private final Store.MetadataSnapshot metadataSnapshot;
@@ -318,6 +328,11 @@ public String toString() {
         }
     }
 
+    /**
+     * The request
+     *
+     * @opensearch.internal
+     */
     public static class Request extends BaseNodesRequest<Request> {
 
         private final ShardId shardId;
@@ -364,6 +379,11 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
+    /**
+     * Metadata for the nodes store files
+     *
+     * @opensearch.internal
+     */
     public static class NodesStoreFilesMetadata extends BaseNodesResponse<NodeStoreFilesMetadata> {
 
         public NodesStoreFilesMetadata(StreamInput in) throws IOException {
@@ -385,6 +405,11 @@ protected void writeNodesTo(StreamOutput out, List<NodeStoreFilesMetadata> nodes
         }
     }
 
+    /**
+     * The node request
+     *
+     * @opensearch.internal
+     */
     public static class NodeRequest extends BaseNodeRequest {
 
         private final ShardId shardId;
@@ -431,6 +456,11 @@ public String getCustomDataPath() {
         }
     }
 
+    /**
+     * The metadata for the node store files
+     *
+     * @opensearch.internal
+     */
     public static class NodeStoreFilesMetadata extends BaseNodeResponse {
 
         private StoreFilesMetadata storeFilesMetadata;
diff --git a/server/src/main/java/org/opensearch/indices/store/package-info.java b/server/src/main/java/org/opensearch/indices/store/package-info.java
new file mode 100644
index 0000000000000..47b19d6d40141
--- /dev/null
+++ b/server/src/main/java/org/opensearch/indices/store/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base package for index store. */
+package org.opensearch.indices.store;
diff --git a/server/src/main/java/org/opensearch/ingest/AbstractProcessor.java b/server/src/main/java/org/opensearch/ingest/AbstractProcessor.java
index a9547f9edeb86..6c22d1b7d21c0 100644
--- a/server/src/main/java/org/opensearch/ingest/AbstractProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/AbstractProcessor.java
@@ -35,6 +35,8 @@
 /**
  * An Abstract Processor that holds tag and description information
  * about the processor.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractProcessor implements Processor {
     protected final String tag;
diff --git a/server/src/main/java/org/opensearch/ingest/CompoundProcessor.java b/server/src/main/java/org/opensearch/ingest/CompoundProcessor.java
index 0857cdd7f9f19..a5f4870029e87 100644
--- a/server/src/main/java/org/opensearch/ingest/CompoundProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/CompoundProcessor.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.metrics.OperationMetrics;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -48,6 +49,8 @@
 /**
  * A Processor that executes a list of other "processors". It executes a separate list of
  * "onFailureProcessors" when any of the processors throw an {@link Exception}.
+ *
+ * @opensearch.internal
  */
 public class CompoundProcessor implements Processor {
     public static final String ON_FAILURE_MESSAGE_FIELD = "on_failure_message";
@@ -58,7 +61,7 @@ public class CompoundProcessor implements Processor {
     private final boolean ignoreFailure;
     private final List<Processor> processors;
     private final List<Processor> onFailureProcessors;
-    private final List<Tuple<Processor, IngestMetric>> processorsWithMetrics;
+    private final List<Tuple<Processor, OperationMetrics>> processorsWithMetrics;
     private final LongSupplier relativeTimeProvider;
 
     CompoundProcessor(LongSupplier relativeTimeProvider, Processor... processor) {
@@ -85,10 +88,10 @@ public CompoundProcessor(boolean ignoreFailure, List<Processor> processors, List
         this.onFailureProcessors = onFailureProcessors;
         this.relativeTimeProvider = relativeTimeProvider;
         this.processorsWithMetrics = new ArrayList<>(processors.size());
-        processors.forEach(p -> processorsWithMetrics.add(new Tuple<>(p, new IngestMetric())));
+        processors.forEach(p -> processorsWithMetrics.add(new Tuple<>(p, new OperationMetrics())));
     }
 
-    List<Tuple<Processor, IngestMetric>> getProcessorsWithMetrics() {
+    List<Tuple<Processor, OperationMetrics>> getProcessorsWithMetrics() {
         return processorsWithMetrics;
     }
 
@@ -153,17 +156,17 @@ void innerExecute(int currentProcessor, IngestDocument ingestDocument, BiConsume
             return;
         }
 
-        Tuple<Processor, IngestMetric> processorWithMetric = processorsWithMetrics.get(currentProcessor);
+        Tuple<Processor, OperationMetrics> processorWithMetric = processorsWithMetrics.get(currentProcessor);
         final Processor processor = processorWithMetric.v1();
-        final IngestMetric metric = processorWithMetric.v2();
+        final OperationMetrics metric = processorWithMetric.v2();
         final long startTimeInNanos = relativeTimeProvider.getAsLong();
-        metric.preIngest();
+        metric.before();
         processor.execute(ingestDocument, (result, e) -> {
             long ingestTimeInMillis = TimeUnit.NANOSECONDS.toMillis(relativeTimeProvider.getAsLong() - startTimeInNanos);
-            metric.postIngest(ingestTimeInMillis);
+            metric.after(ingestTimeInMillis);
 
             if (e != null) {
-                metric.ingestFailed();
+                metric.failed();
                 if (ignoreFailure) {
                     innerExecute(currentProcessor + 1, ingestDocument, handler);
                 } else {
diff --git a/server/src/main/java/org/opensearch/ingest/ConditionalProcessor.java b/server/src/main/java/org/opensearch/ingest/ConditionalProcessor.java
index dcb249d75afc6..8bf489805f7ca 100644
--- a/server/src/main/java/org/opensearch/ingest/ConditionalProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/ConditionalProcessor.java
@@ -32,8 +32,7 @@
 
 package org.opensearch.ingest;
 
-import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.script.DynamicMap;
+import org.opensearch.common.metrics.OperationMetrics;
 import org.opensearch.script.IngestConditionalScript;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptException;
@@ -51,29 +50,24 @@
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
-import java.util.function.Function;
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
 
 import static org.opensearch.ingest.ConfigurationUtils.newConfigurationException;
 
+/**
+ * Ingest processor based on specific conditions
+ *
+ * @opensearch.internal
+ */
 public class ConditionalProcessor extends AbstractProcessor implements WrappingProcessor {
 
-    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> FUNCTIONS = org.opensearch.common.collect.Map.of("_type", value -> {
-        deprecationLogger.deprecate(
-            "conditional-processor__type",
-            "[types removal] Looking up doc types [_type] in scripts is deprecated."
-        );
-        return value;
-    });
-
     static final String TYPE = "conditional";
 
     private final Script condition;
     private final ScriptService scriptService;
     private final Processor processor;
-    private final IngestMetric metric;
+    private final OperationMetrics metric;
     private final LongSupplier relativeTimeProvider;
     private final IngestConditionalScript precompiledConditionScript;
 
@@ -93,7 +87,7 @@ public class ConditionalProcessor extends AbstractProcessor implements WrappingP
         this.condition = script;
         this.scriptService = scriptService;
         this.processor = processor;
-        this.metric = new IngestMetric();
+        this.metric = new OperationMetrics();
         this.relativeTimeProvider = relativeTimeProvider;
 
         try {
@@ -121,12 +115,12 @@ public void execute(IngestDocument ingestDocument, BiConsumer<IngestDocument, Ex
 
         if (matches) {
             final long startTimeInNanos = relativeTimeProvider.getAsLong();
-            metric.preIngest();
+            metric.before();
             processor.execute(ingestDocument, (result, e) -> {
                 long ingestTimeInMillis = TimeUnit.NANOSECONDS.toMillis(relativeTimeProvider.getAsLong() - startTimeInNanos);
-                metric.postIngest(ingestTimeInMillis);
+                metric.after(ingestTimeInMillis);
                 if (e != null) {
-                    metric.ingestFailed();
+                    metric.failed();
                     handler.accept(null, e);
                 } else {
                     handler.accept(result, null);
@@ -148,14 +142,14 @@ boolean evaluate(IngestDocument ingestDocument) {
             IngestConditionalScript.Factory factory = scriptService.compile(condition, IngestConditionalScript.CONTEXT);
             script = factory.newInstance(condition.getParams());
         }
-        return script.execute(new UnmodifiableIngestData(new DynamicMap(ingestDocument.getSourceAndMetadata(), FUNCTIONS)));
+        return script.execute(new UnmodifiableIngestData(ingestDocument.getSourceAndMetadata()));
     }
 
     public Processor getInnerProcessor() {
         return processor;
     }
 
-    IngestMetric getMetric() {
+    OperationMetrics getMetric() {
         return metric;
     }
 
diff --git a/server/src/main/java/org/opensearch/ingest/ConfigurationUtils.java b/server/src/main/java/org/opensearch/ingest/ConfigurationUtils.java
index 2f8516181b5e3..f97388a8262ff 100644
--- a/server/src/main/java/org/opensearch/ingest/ConfigurationUtils.java
+++ b/server/src/main/java/org/opensearch/ingest/ConfigurationUtils.java
@@ -32,23 +32,24 @@
 
 package org.opensearch.ingest;
 
-import java.io.IOException;
-import java.io.InputStream;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.Nullable;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.ScriptType;
 import org.opensearch.script.TemplateScript;
 
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -58,10 +59,16 @@
 
 import static org.opensearch.script.Script.DEFAULT_TEMPLATE_LANG;
 
+/**
+ * Utility class for ingest processor configurations
+ *
+ * @opensearch.internal
+ */
 public final class ConfigurationUtils {
 
     public static final String TAG_KEY = "tag";
     public static final String DESCRIPTION_KEY = "description";
+    public static final String IGNORE_FAILURE_KEY = "ignore_failure";
 
     private ConfigurationUtils() {}
 
@@ -189,7 +196,7 @@ public static String readOptionalStringOrIntProperty(
         return readStringOrInt(processorType, processorTag, propertyName, value);
     }
 
-    public static Boolean readBooleanProperty(
+    public static boolean readBooleanProperty(
         String processorType,
         String processorTag,
         Map<String, Object> configuration,
@@ -209,7 +216,7 @@ private static Boolean readBoolean(String processorType, String processorTag, St
             return null;
         }
         if (value instanceof Boolean) {
-            return (Boolean) value;
+            return (boolean) value;
         }
         throw newConfigurationException(
             processorType,
@@ -504,9 +511,11 @@ public static Processor readProcessor(
         Map<String, Processor.Factory> processorFactories,
         ScriptService scriptService,
         String type,
-        Object config
+        @Nullable Object config
     ) throws Exception {
-        if (config instanceof Map) {
+        if (config == null) {
+            throw newConfigurationException(type, null, null, "the config of processor [" + type + "] cannot be null");
+        } else if (config instanceof Map) {
             return readProcessor(processorFactories, scriptService, type, (Map<String, Object>) config);
         } else if (config instanceof String && "script".equals(type)) {
             Map<String, Object> normalizedScript = new HashMap<>(1);
@@ -521,14 +530,18 @@ public static Processor readProcessor(
         Map<String, Processor.Factory> processorFactories,
         ScriptService scriptService,
         String type,
-        Map<String, Object> config
+        @Nullable Map<String, Object> config
     ) throws Exception {
+        if (config == null) {
+            throw newConfigurationException(type, null, null, "expect the config of processor [" + type + "] to be map, but is null");
+        }
         String tag = ConfigurationUtils.readOptionalStringProperty(null, null, config, TAG_KEY);
         String description = ConfigurationUtils.readOptionalStringProperty(null, tag, config, DESCRIPTION_KEY);
+        boolean ignoreFailure = ConfigurationUtils.readBooleanProperty(null, null, config, IGNORE_FAILURE_KEY, false);
         Script conditionalScript = extractConditional(config);
         Processor.Factory factory = processorFactories.get(type);
+
         if (factory != null) {
-            boolean ignoreFailure = ConfigurationUtils.readBooleanProperty(null, null, config, "ignore_failure", false);
             List<Map<String, Object>> onFailureProcessorConfigs = ConfigurationUtils.readOptionalList(
                 null,
                 null,
@@ -571,7 +584,7 @@ private static Script extractConditional(Map<String, Object> config) throws IOEx
             try (
                 XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(normalizeScript(scriptSource));
                 InputStream stream = BytesReference.bytes(builder).streamInput();
-                XContentParser parser = XContentType.JSON.xContent()
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
             ) {
                 return Script.parse(parser);
diff --git a/server/src/main/java/org/opensearch/ingest/DropProcessor.java b/server/src/main/java/org/opensearch/ingest/DropProcessor.java
index 8a9662a31d7c9..44aee29c7b4a6 100644
--- a/server/src/main/java/org/opensearch/ingest/DropProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/DropProcessor.java
@@ -37,6 +37,8 @@
 /**
  * Drop processor only returns {@code null} for the execution result to indicate that any document
  * executed by it should not be indexed.
+ *
+ * @opensearch.internal
  */
 public final class DropProcessor extends AbstractProcessor {
 
@@ -56,6 +58,11 @@ public String getType() {
         return TYPE;
     }
 
+    /**
+     * A factory for the processor.
+     *
+     * @opensearch.internal
+     */
     public static final class Factory implements Processor.Factory {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/ingest/IngestDocument.java b/server/src/main/java/org/opensearch/ingest/IngestDocument.java
index b18946486f8c6..e0de0a9488ad9 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestDocument.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestDocument.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.ingest;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IndexFieldMapper;
@@ -59,6 +59,8 @@
 
 /**
  * Represents a single document being captured before indexing and holds the source and metadata (like id, type and index).
+ *
+ * @opensearch.internal
  */
 public final class IngestDocument {
 
@@ -843,6 +845,11 @@ public String toString() {
         return "IngestDocument{" + " sourceAndMetadata=" + sourceAndMetadata + ", ingestMetadata=" + ingestMetadata + '}';
     }
 
+    /**
+     * The ingest metadata.
+     *
+     * @opensearch.internal
+     */
     public enum Metadata {
         INDEX(IndexFieldMapper.NAME),
         ID(IdFieldMapper.NAME),
diff --git a/server/src/main/java/org/opensearch/ingest/IngestInfo.java b/server/src/main/java/org/opensearch/ingest/IngestInfo.java
index e8d4e0dc0a73e..ca359edb1715a 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestInfo.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestInfo.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.ingest;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.List;
@@ -43,6 +43,11 @@
 import java.util.Set;
 import java.util.TreeSet;
 
+/**
+ * Information about an ingest event
+ *
+ * @opensearch.internal
+ */
 public class IngestInfo implements ReportingService.Info {
 
     private final Set<ProcessorInfo> processors;
diff --git a/server/src/main/java/org/opensearch/ingest/IngestMetadata.java b/server/src/main/java/org/opensearch/ingest/IngestMetadata.java
index 36fea51e2e2f2..9518a2135be89 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestMetadata.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestMetadata.java
@@ -37,12 +37,12 @@
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.NamedDiff;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,6 +54,8 @@
 
 /**
  * Holds the ingest pipelines that are available in the cluster
+ *
+ * @opensearch.internal
  */
 public final class IngestMetadata implements Metadata.Custom {
 
diff --git a/server/src/main/java/org/opensearch/ingest/IngestMetric.java b/server/src/main/java/org/opensearch/ingest/IngestMetric.java
deleted file mode 100644
index aac8c810f772a..0000000000000
--- a/server/src/main/java/org/opensearch/ingest/IngestMetric.java
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.ingest;
-
-import org.opensearch.common.metrics.CounterMetric;
-import org.opensearch.common.metrics.MeanMetric;
-
-import java.util.concurrent.atomic.AtomicLong;
-
-/**
- * <p>Metrics to measure ingest actions.
- * <p>This counts measure documents and timings for a given scope.
- * The scope is determined by the calling code. For example you can use this class to count all documents across all pipeline,
- * or you can use this class to count documents for a given pipeline or a specific processor.
- * This class does not make assumptions about it's given scope.
- */
-class IngestMetric {
-
-    /**
-     * The time it takes to complete the measured item.
-     */
-    private final MeanMetric ingestTime = new MeanMetric();
-    /**
-     * The current count of things being measure. Should most likely ever be 0 or 1.
-     * Useful when aggregating multiple metrics to see how many things are in flight.
-     */
-    private final AtomicLong ingestCurrent = new AtomicLong();
-    /**
-     * The ever increasing count of things being measured
-     */
-    private final CounterMetric ingestCount = new CounterMetric();
-    /**
-     * The only increasing count of failures
-     */
-    private final CounterMetric ingestFailed = new CounterMetric();
-
-    /**
-     * Call this prior to the ingest action.
-     */
-    void preIngest() {
-        ingestCurrent.incrementAndGet();
-    }
-
-    /**
-     * Call this after the performing the ingest action, even if the action failed.
-     * @param ingestTimeInMillis The time it took to perform the action.
-     */
-    void postIngest(long ingestTimeInMillis) {
-        ingestCurrent.decrementAndGet();
-        ingestTime.inc(ingestTimeInMillis);
-        ingestCount.inc();
-    }
-
-    /**
-     * Call this if the ingest action failed.
-     */
-    void ingestFailed() {
-        ingestFailed.inc();
-    }
-
-    /**
-     * <p>Add two sets of metrics together.
-     * <p><strong>Note -</strong> this method does <strong>not</strong> add the current count values.
-     * The current count value is ephemeral and requires a increase/decrease operation pairs to keep the value correct.
-     *
-     * @param metrics The metric to add.
-     */
-    void add(IngestMetric metrics) {
-        ingestCount.inc(metrics.ingestCount.count());
-        ingestTime.inc(metrics.ingestTime.sum());
-        ingestFailed.inc(metrics.ingestFailed.count());
-    }
-
-    /**
-     * Creates a serializable representation for these metrics.
-     */
-    IngestStats.Stats createStats() {
-        return new IngestStats.Stats(ingestCount.count(), ingestTime.sum(), ingestCurrent.get(), ingestFailed.count());
-    }
-}
diff --git a/server/src/main/java/org/opensearch/ingest/IngestProcessorException.java b/server/src/main/java/org/opensearch/ingest/IngestProcessorException.java
index 72e1cde5cac69..c7920d73b87aa 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestProcessorException.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestProcessorException.java
@@ -34,13 +34,15 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A dedicated wrapper for exceptions encountered executing an ingest processor. The wrapper is needed as we currently only unwrap causes
  * for instances of {@link OpenSearchWrapperException}.
+ *
+ * @opensearch.internal
  */
 public class IngestProcessorException extends OpenSearchException implements OpenSearchWrapperException {
 
diff --git a/server/src/main/java/org/opensearch/ingest/IngestService.java b/server/src/main/java/org/opensearch/ingest/IngestService.java
index cbd5fa71b27de..91003e963e302 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestService.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestService.java
@@ -35,10 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.OpenSearchParseException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.bulk.TransportBulkAction;
 import org.opensearch.action.index.IndexRequest;
@@ -56,19 +55,23 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.metrics.OperationMetrics;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.service.ReportingService;
 import org.opensearch.env.Environment;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.analysis.AnalysisRegistry;
-import org.opensearch.node.ReportingService;
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ThreadPool;
@@ -92,6 +95,8 @@
 
 /**
  * Holder class for several ingest related services.
+ *
+ * @opensearch.internal
  */
 public class IngestService implements ClusterStateApplier, ReportingService<IngestInfo> {
 
@@ -110,8 +115,10 @@ public class IngestService implements ClusterStateApplier, ReportingService<Inge
     // are loaded, so in the cluster state we just save the pipeline config and here we keep the actual pipelines around.
     private volatile Map<String, PipelineHolder> pipelines = Collections.emptyMap();
     private final ThreadPool threadPool;
-    private final IngestMetric totalMetrics = new IngestMetric();
+    private final OperationMetrics totalMetrics = new OperationMetrics();
     private final List<Consumer<ClusterState>> ingestClusterStateListeners = new CopyOnWriteArrayList<>();
+    private final ClusterManagerTaskThrottler.ThrottlingKey putPipelineTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deletePipelineTaskKey;
     private volatile ClusterState state;
 
     public IngestService(
@@ -139,8 +146,11 @@ public IngestService(
                 threadPool.generic()::execute
             )
         );
-
         this.threadPool = threadPool;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        putPipelineTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.PUT_PIPELINE_KEY, true);
+        deletePipelineTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_PIPELINE_KEY, true);
     }
 
     private static Map<String, Processor.Factory> processorFactories(List<IngestPlugin> ingestPlugins, Processor.Parameters parameters) {
@@ -289,6 +299,11 @@ protected AcknowledgedResponse newResponse(boolean acknowledged) {
                 public ClusterState execute(ClusterState currentState) {
                     return innerDelete(request, currentState);
                 }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return deletePipelineTaskKey;
+                }
             }
         );
     }
@@ -383,6 +398,11 @@ protected AcknowledgedResponse newResponse(boolean acknowledged) {
                 public ClusterState execute(ClusterState currentState) {
                     return innerPut(request, currentState);
                 }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return putPipelineTaskKey;
+                }
             }
         );
     }
@@ -421,17 +441,17 @@ Map<String, PipelineHolder> pipelines() {
      * Recursive method to obtain all of the non-failure processors for given compoundProcessor. Since conditionals are implemented as
      * wrappers to the actual processor, always prefer the actual processor's metric over the conditional processor's metric.
      * @param compoundProcessor The compound processor to start walking the non-failure processors
-     * @param processorMetrics The list of {@link Processor} {@link IngestMetric} tuples.
+     * @param processorMetrics The list of {@link Processor} {@link OperationMetrics} tuples.
      * @return the processorMetrics for all non-failure processor that belong to the original compoundProcessor
      */
-    private static List<Tuple<Processor, IngestMetric>> getProcessorMetrics(
+    private static List<Tuple<Processor, OperationMetrics>> getProcessorMetrics(
         CompoundProcessor compoundProcessor,
-        List<Tuple<Processor, IngestMetric>> processorMetrics
+        List<Tuple<Processor, OperationMetrics>> processorMetrics
     ) {
         // only surface the top level non-failure processors, on-failure processor times will be included in the top level non-failure
-        for (Tuple<Processor, IngestMetric> processorWithMetric : compoundProcessor.getProcessorsWithMetrics()) {
+        for (Tuple<Processor, OperationMetrics> processorWithMetric : compoundProcessor.getProcessorsWithMetrics()) {
             Processor processor = processorWithMetric.v1();
-            IngestMetric metric = processorWithMetric.v2();
+            OperationMetrics metric = processorWithMetric.v2();
             if (processor instanceof CompoundProcessor) {
                 getProcessorMetrics((CompoundProcessor) processor, processorMetrics);
             } else {
@@ -454,7 +474,7 @@ public static ClusterState innerPut(PutPipelineRequest request, ClusterState cur
             pipelines = new HashMap<>();
         }
 
-        pipelines.put(request.getId(), new PipelineConfiguration(request.getId(), request.getSource(), request.getXContentType()));
+        pipelines.put(request.getId(), new PipelineConfiguration(request.getId(), request.getSource(), request.getMediaType()));
         ClusterState.Builder newState = ClusterState.builder(currentState);
         newState.metadata(
             Metadata.builder(currentState.getMetadata()).putCustom(IngestMetadata.TYPE, new IngestMetadata(pipelines)).build()
@@ -467,7 +487,7 @@ void validatePipeline(Map<DiscoveryNode, IngestInfo> ingestInfos, PutPipelineReq
             throw new IllegalStateException("Ingest info is empty");
         }
 
-        Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2();
+        Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getMediaType()).v2();
         Pipeline pipeline = Pipeline.create(request.getId(), pipelineConfig, processorFactories, scriptService);
         List<Exception> exceptions = new ArrayList<>();
         for (Processor processor : pipeline.flattenAllProcessors()) {
@@ -595,7 +615,7 @@ private void executePipelines(
 
                     if (Objects.equals(originalIndex, newIndex) == false) {
                         if (hasFinalPipeline && it.hasNext() == false) {
-                            totalMetrics.ingestFailed();
+                            totalMetrics.failed();
                             onFailure.accept(
                                 slot,
                                 new IllegalStateException("final pipeline [" + pipelineId + "] can't change the target index")
@@ -661,11 +681,11 @@ public IngestStats stats() {
             Pipeline pipeline = holder.pipeline;
             CompoundProcessor rootProcessor = pipeline.getCompoundProcessor();
             statsBuilder.addPipelineMetrics(id, pipeline.getMetrics());
-            List<Tuple<Processor, IngestMetric>> processorMetrics = new ArrayList<>();
+            List<Tuple<Processor, OperationMetrics>> processorMetrics = new ArrayList<>();
             getProcessorMetrics(rootProcessor, processorMetrics);
             processorMetrics.forEach(t -> {
                 Processor processor = t.v1();
-                IngestMetric processorMetric = t.v2();
+                OperationMetrics processorMetric = t.v2();
                 statsBuilder.addProcessorMetrics(id, getProcessorName(processor), processor.getType(), processorMetric);
             });
         });
@@ -720,7 +740,7 @@ private void innerExecute(
         long startTimeInNanos = System.nanoTime();
         // the pipeline specific stat holder may not exist and that is fine:
         // (e.g. the pipeline may have been removed while we're ingesting a document
-        totalMetrics.preIngest();
+        totalMetrics.before();
         String index = indexRequest.index();
         String id = indexRequest.id();
         String routing = indexRequest.routing();
@@ -730,9 +750,9 @@ private void innerExecute(
         IngestDocument ingestDocument = new IngestDocument(index, id, routing, version, versionType, sourceAsMap);
         ingestDocument.executePipeline(pipeline, (result, e) -> {
             long ingestTimeInMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTimeInNanos);
-            totalMetrics.postIngest(ingestTimeInMillis);
+            totalMetrics.after(ingestTimeInMillis);
             if (e != null) {
-                totalMetrics.ingestFailed();
+                totalMetrics.failed();
                 handler.accept(e);
             } else if (result == null) {
                 itemDroppedHandler.accept(slot);
@@ -816,22 +836,22 @@ void innerUpdatePipelines(IngestMetadata newIngestMetadata) {
                 }
                 Pipeline oldPipeline = previous.pipeline;
                 newPipeline.getMetrics().add(oldPipeline.getMetrics());
-                List<Tuple<Processor, IngestMetric>> oldPerProcessMetrics = new ArrayList<>();
-                List<Tuple<Processor, IngestMetric>> newPerProcessMetrics = new ArrayList<>();
+                List<Tuple<Processor, OperationMetrics>> oldPerProcessMetrics = new ArrayList<>();
+                List<Tuple<Processor, OperationMetrics>> newPerProcessMetrics = new ArrayList<>();
                 getProcessorMetrics(oldPipeline.getCompoundProcessor(), oldPerProcessMetrics);
                 getProcessorMetrics(newPipeline.getCompoundProcessor(), newPerProcessMetrics);
                 // Best attempt to populate new processor metrics using a parallel array of the old metrics. This is not ideal since
                 // the per processor metrics may get reset when the arrays don't match. However, to get to an ideal model, unique and
                 // consistent id's per processor and/or semantic equals for each processor will be needed.
                 if (newPerProcessMetrics.size() == oldPerProcessMetrics.size()) {
-                    Iterator<Tuple<Processor, IngestMetric>> oldMetricsIterator = oldPerProcessMetrics.iterator();
-                    for (Tuple<Processor, IngestMetric> compositeMetric : newPerProcessMetrics) {
+                    Iterator<Tuple<Processor, OperationMetrics>> oldMetricsIterator = oldPerProcessMetrics.iterator();
+                    for (Tuple<Processor, OperationMetrics> compositeMetric : newPerProcessMetrics) {
                         String type = compositeMetric.v1().getType();
-                        IngestMetric metric = compositeMetric.v2();
+                        OperationMetrics metric = compositeMetric.v2();
                         if (oldMetricsIterator.hasNext()) {
-                            Tuple<Processor, IngestMetric> oldCompositeMetric = oldMetricsIterator.next();
+                            Tuple<Processor, OperationMetrics> oldCompositeMetric = oldMetricsIterator.next();
                             String oldType = oldCompositeMetric.v1().getType();
-                            IngestMetric oldMetric = oldCompositeMetric.v2();
+                            OperationMetrics oldMetric = oldCompositeMetric.v2();
                             if (type.equals(oldType)) {
                                 metric.add(oldMetric);
                             }
diff --git a/server/src/main/java/org/opensearch/ingest/IngestStats.java b/server/src/main/java/org/opensearch/ingest/IngestStats.java
index c1b08cb7e62f9..ff4cfeb7b3aac 100644
--- a/server/src/main/java/org/opensearch/ingest/IngestStats.java
+++ b/server/src/main/java/org/opensearch/ingest/IngestStats.java
@@ -33,12 +33,13 @@
 package org.opensearch.ingest;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.metrics.OperationMetrics;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,10 +48,14 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.concurrent.TimeUnit;
 
+/**
+ * OperationStats for an ingest processor pipeline
+ *
+ * @opensearch.internal
+ */
 public class IngestStats implements Writeable, ToXContentFragment {
-    private final Stats totalStats;
+    private final OperationStats totalStats;
     private final List<PipelineStat> pipelineStats;
     private final Map<String, List<ProcessorStat>> processorStats;
 
@@ -60,7 +65,7 @@ public class IngestStats implements Writeable, ToXContentFragment {
      * @param pipelineStats - The stats for a given ingest pipeline.
      * @param processorStats - The per-processor stats for a given pipeline. A map keyed by the pipeline identifier.
      */
-    public IngestStats(Stats totalStats, List<PipelineStat> pipelineStats, Map<String, List<ProcessorStat>> processorStats) {
+    public IngestStats(OperationStats totalStats, List<PipelineStat> pipelineStats, Map<String, List<ProcessorStat>> processorStats) {
         this.totalStats = totalStats;
         this.pipelineStats = pipelineStats;
         this.processorStats = processorStats;
@@ -70,13 +75,13 @@ public IngestStats(Stats totalStats, List<PipelineStat> pipelineStats, Map<Strin
      * Read from a stream.
      */
     public IngestStats(StreamInput in) throws IOException {
-        this.totalStats = new Stats(in);
+        this.totalStats = new OperationStats(in);
         int size = in.readVInt();
         this.pipelineStats = new ArrayList<>(size);
         this.processorStats = new HashMap<>(size);
         for (int i = 0; i < size; i++) {
             String pipelineId = in.readString();
-            Stats pipelineStat = new Stats(in);
+            OperationStats pipelineStat = new OperationStats(in);
             this.pipelineStats.add(new PipelineStat(pipelineId, pipelineStat));
             int processorsSize = in.readVInt();
             List<ProcessorStat> processorStatsPerPipeline = new ArrayList<>(processorsSize);
@@ -86,7 +91,7 @@ public IngestStats(StreamInput in) throws IOException {
                 if (in.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
                     processorType = in.readString();
                 }
-                Stats processorStat = new Stats(in);
+                OperationStats processorStat = new OperationStats(in);
                 processorStatsPerPipeline.add(new ProcessorStat(processorName, processorType, processorStat));
             }
             this.processorStats.put(pipelineId, processorStatsPerPipeline);
@@ -148,7 +153,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
-    public Stats getTotalStats() {
+    public OperationStats getTotalStats() {
         return totalStats;
     }
 
@@ -175,111 +180,25 @@ public int hashCode() {
         return Objects.hash(totalStats, pipelineStats, processorStats);
     }
 
-    public static class Stats implements Writeable, ToXContentFragment {
-
-        private final long ingestCount;
-        private final long ingestTimeInMillis;
-        private final long ingestCurrent;
-        private final long ingestFailedCount;
-
-        public Stats(long ingestCount, long ingestTimeInMillis, long ingestCurrent, long ingestFailedCount) {
-            this.ingestCount = ingestCount;
-            this.ingestTimeInMillis = ingestTimeInMillis;
-            this.ingestCurrent = ingestCurrent;
-            this.ingestFailedCount = ingestFailedCount;
-        }
-
-        /**
-         * Read from a stream.
-         */
-        public Stats(StreamInput in) throws IOException {
-            ingestCount = in.readVLong();
-            ingestTimeInMillis = in.readVLong();
-            ingestCurrent = in.readVLong();
-            ingestFailedCount = in.readVLong();
-        }
-
-        @Override
-        public void writeTo(StreamOutput out) throws IOException {
-            out.writeVLong(ingestCount);
-            out.writeVLong(ingestTimeInMillis);
-            out.writeVLong(ingestCurrent);
-            out.writeVLong(ingestFailedCount);
-        }
-
-        /**
-         * @return The total number of executed ingest preprocessing operations.
-         */
-        public long getIngestCount() {
-            return ingestCount;
-        }
-
-        /**
-         * @return The total time spent of ingest preprocessing in millis.
-         */
-        public long getIngestTimeInMillis() {
-            return ingestTimeInMillis;
-        }
-
-        /**
-         * @return The total number of ingest preprocessing operations currently executing.
-         */
-        public long getIngestCurrent() {
-            return ingestCurrent;
-        }
-
-        /**
-         * @return The total number of ingest preprocessing operations that have failed.
-         */
-        public long getIngestFailedCount() {
-            return ingestFailedCount;
-        }
-
-        @Override
-        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            builder.field("count", ingestCount);
-            builder.humanReadableField("time_in_millis", "time", new TimeValue(ingestTimeInMillis, TimeUnit.MILLISECONDS));
-            builder.field("current", ingestCurrent);
-            builder.field("failed", ingestFailedCount);
-            return builder;
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (this == o) return true;
-            if (o == null || getClass() != o.getClass()) return false;
-            IngestStats.Stats that = (IngestStats.Stats) o;
-            return Objects.equals(ingestCount, that.ingestCount)
-                && Objects.equals(ingestTimeInMillis, that.ingestTimeInMillis)
-                && Objects.equals(ingestFailedCount, that.ingestFailedCount)
-                && Objects.equals(ingestCurrent, that.ingestCurrent);
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(ingestCount, ingestTimeInMillis, ingestFailedCount, ingestCurrent);
-        }
-    }
-
     /**
-     * Easy conversion from scoped {@link IngestMetric} objects to a serializable Stats objects
+     * Easy conversion from scoped {@link OperationMetrics} objects to a serializable OperationStats objects
      */
     static class Builder {
-        private Stats totalStats;
+        private OperationStats totalStats;
         private List<PipelineStat> pipelineStats = new ArrayList<>();
         private Map<String, List<ProcessorStat>> processorStats = new HashMap<>();
 
-        Builder addTotalMetrics(IngestMetric totalMetric) {
+        Builder addTotalMetrics(OperationMetrics totalMetric) {
             this.totalStats = totalMetric.createStats();
             return this;
         }
 
-        Builder addPipelineMetrics(String pipelineId, IngestMetric pipelineMetric) {
+        Builder addPipelineMetrics(String pipelineId, OperationMetrics pipelineMetric) {
             this.pipelineStats.add(new PipelineStat(pipelineId, pipelineMetric.createStats()));
             return this;
         }
 
-        Builder addProcessorMetrics(String pipelineId, String processorName, String processorType, IngestMetric metric) {
+        Builder addProcessorMetrics(String pipelineId, String processorName, String processorType, OperationMetrics metric) {
             this.processorStats.computeIfAbsent(pipelineId, k -> new ArrayList<>())
                 .add(new ProcessorStat(processorName, processorType, metric.createStats()));
             return this;
@@ -295,9 +214,9 @@ IngestStats build() {
      */
     public static class PipelineStat {
         private final String pipelineId;
-        private final Stats stats;
+        private final OperationStats stats;
 
-        public PipelineStat(String pipelineId, Stats stats) {
+        public PipelineStat(String pipelineId, OperationStats stats) {
             this.pipelineId = pipelineId;
             this.stats = stats;
         }
@@ -306,7 +225,7 @@ public String getPipelineId() {
             return pipelineId;
         }
 
-        public Stats getStats() {
+        public OperationStats getStats() {
             return stats;
         }
 
@@ -330,9 +249,9 @@ public int hashCode() {
     public static class ProcessorStat {
         private final String name;
         private final String type;
-        private final Stats stats;
+        private final OperationStats stats;
 
-        public ProcessorStat(String name, String type, Stats stats) {
+        public ProcessorStat(String name, String type, OperationStats stats) {
             this.name = name;
             this.type = type;
             this.stats = stats;
@@ -346,7 +265,7 @@ public String getType() {
             return type;
         }
 
-        public Stats getStats() {
+        public OperationStats getStats() {
             return stats;
         }
 
diff --git a/server/src/main/java/org/opensearch/ingest/Pipeline.java b/server/src/main/java/org/opensearch/ingest/Pipeline.java
index 7447213257c24..37643e48ed2be 100644
--- a/server/src/main/java/org/opensearch/ingest/Pipeline.java
+++ b/server/src/main/java/org/opensearch/ingest/Pipeline.java
@@ -34,6 +34,8 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.metrics.OperationMetrics;
+import org.opensearch.script.ScriptService;
 
 import java.util.Arrays;
 import java.util.Collections;
@@ -43,10 +45,10 @@
 import java.util.function.BiConsumer;
 import java.util.function.LongSupplier;
 
-import org.opensearch.script.ScriptService;
-
 /**
  * A pipeline is a list of {@link Processor} instances grouped under a unique id.
+ *
+ * @opensearch.internal
  */
 public final class Pipeline {
 
@@ -61,7 +63,7 @@ public final class Pipeline {
     @Nullable
     private final Integer version;
     private final CompoundProcessor compoundProcessor;
-    private final IngestMetric metrics;
+    private final OperationMetrics metrics;
     private final LongSupplier relativeTimeProvider;
 
     public Pipeline(String id, @Nullable String description, @Nullable Integer version, CompoundProcessor compoundProcessor) {
@@ -80,7 +82,7 @@ public Pipeline(String id, @Nullable String description, @Nullable Integer versi
         this.description = description;
         this.compoundProcessor = compoundProcessor;
         this.version = version;
-        this.metrics = new IngestMetric();
+        this.metrics = new OperationMetrics();
         this.relativeTimeProvider = relativeTimeProvider;
     }
 
@@ -127,12 +129,12 @@ public static Pipeline create(
      */
     public void execute(IngestDocument ingestDocument, BiConsumer<IngestDocument, Exception> handler) {
         final long startTimeInNanos = relativeTimeProvider.getAsLong();
-        metrics.preIngest();
+        metrics.before();
         compoundProcessor.execute(ingestDocument, (result, e) -> {
             long ingestTimeInMillis = TimeUnit.NANOSECONDS.toMillis(relativeTimeProvider.getAsLong() - startTimeInNanos);
-            metrics.postIngest(ingestTimeInMillis);
+            metrics.after(ingestTimeInMillis);
             if (e != null) {
-                metrics.ingestFailed();
+                metrics.failed();
             }
             handler.accept(result, e);
         });
@@ -196,7 +198,7 @@ public List<Processor> flattenAllProcessors() {
     /**
      * The metrics associated with this pipeline.
      */
-    public IngestMetric getMetrics() {
+    public OperationMetrics getMetrics() {
         return metrics;
     }
 }
diff --git a/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java b/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
index 0e58cea3c9904..d59d9d6da5717 100644
--- a/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
+++ b/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
@@ -32,19 +32,22 @@
 
 package org.opensearch.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
@@ -52,6 +55,8 @@
 
 /**
  * Encapsulates a pipeline's id and configuration as a blob
+ *
+ * @opensearch.internal
  */
 public final class PipelineConfiguration extends AbstractDiffable<PipelineConfiguration> implements ToXContentObject {
 
@@ -74,19 +79,22 @@ private static class Builder {
 
         private String id;
         private BytesReference config;
-        private XContentType xContentType;
+        private MediaType mediaType;
 
         void setId(String id) {
             this.id = id;
         }
 
-        void setConfig(BytesReference config, XContentType xContentType) {
+        void setConfig(BytesReference config, MediaType mediaType) {
+            if (mediaType instanceof XContentType == false) {
+                throw new IllegalArgumentException("PipelineConfiguration does not support media type [" + mediaType.getClass() + "]");
+            }
             this.config = config;
-            this.xContentType = xContentType;
+            this.mediaType = mediaType;
         }
 
         PipelineConfiguration build() {
-            return new PipelineConfiguration(id, config, xContentType);
+            return new PipelineConfiguration(id, config, mediaType);
         }
     }
 
@@ -95,12 +103,12 @@ PipelineConfiguration build() {
     // and the way the map of maps config is read requires a deep copy (it removes instead of gets entries to check for unused options)
     // also the get pipeline api just directly returns this to the caller
     private final BytesReference config;
-    private final XContentType xContentType;
+    private final MediaType mediaType;
 
-    public PipelineConfiguration(String id, BytesReference config, XContentType xContentType) {
+    public PipelineConfiguration(String id, BytesReference config, MediaType mediaType) {
         this.id = Objects.requireNonNull(id);
         this.config = Objects.requireNonNull(config);
-        this.xContentType = Objects.requireNonNull(xContentType);
+        this.mediaType = Objects.requireNonNull(mediaType);
     }
 
     public String getId() {
@@ -108,12 +116,12 @@ public String getId() {
     }
 
     public Map<String, Object> getConfigAsMap() {
-        return XContentHelper.convertToMap(config, true, xContentType).v2();
+        return XContentHelper.convertToMap(config, true, mediaType).v2();
     }
 
     // pkg-private for tests
-    XContentType getXContentType() {
-        return xContentType;
+    MediaType getMediaType() {
+        return mediaType;
     }
 
     // pkg-private for tests
@@ -131,7 +139,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     }
 
     public static PipelineConfiguration readFrom(StreamInput in) throws IOException {
-        return new PipelineConfiguration(in.readString(), in.readBytesReference(), in.readEnum(XContentType.class));
+        return new PipelineConfiguration(
+            in.readString(),
+            in.readBytesReference(),
+            in.getVersion().onOrAfter(Version.V_2_10_0) ? in.readMediaType() : in.readEnum(XContentType.class)
+        );
     }
 
     public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IOException {
@@ -140,14 +152,18 @@ public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IO
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(id);
         out.writeBytesReference(config);
-        out.writeEnum(xContentType);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/ingest/PipelineProcessor.java b/server/src/main/java/org/opensearch/ingest/PipelineProcessor.java
index 5bb651e84bc0b..300b9824b277a 100644
--- a/server/src/main/java/org/opensearch/ingest/PipelineProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/PipelineProcessor.java
@@ -37,6 +37,11 @@
 import java.util.Map;
 import java.util.function.BiConsumer;
 
+/**
+ * Processes an ingest pipeline
+ *
+ * @opensearch.internal
+ */
 public class PipelineProcessor extends AbstractProcessor {
 
     public static final String TYPE = "pipeline";
@@ -86,6 +91,11 @@ TemplateScript.Factory getPipelineTemplate() {
         return pipelineTemplate;
     }
 
+    /**
+     * Factory for the processor.
+     *
+     * @opensearch.internal
+     */
     public static final class Factory implements Processor.Factory {
 
         private final IngestService ingestService;
diff --git a/server/src/main/java/org/opensearch/ingest/Processor.java b/server/src/main/java/org/opensearch/ingest/Processor.java
index 84fa0e9496bd7..e0f196dfcb115 100644
--- a/server/src/main/java/org/opensearch/ingest/Processor.java
+++ b/server/src/main/java/org/opensearch/ingest/Processor.java
@@ -50,6 +50,8 @@
  * Whether changes are made and what exactly is modified is up to the implementation.
  *
  * Processors may get called concurrently and thus need to be thread-safe.
+ *
+ * @opensearch.internal
  */
 public interface Processor {
 
diff --git a/server/src/main/java/org/opensearch/ingest/ProcessorInfo.java b/server/src/main/java/org/opensearch/ingest/ProcessorInfo.java
index b4ea371f8e3ba..276e0ac234a8e 100644
--- a/server/src/main/java/org/opensearch/ingest/ProcessorInfo.java
+++ b/server/src/main/java/org/opensearch/ingest/ProcessorInfo.java
@@ -32,15 +32,19 @@
 
 package org.opensearch.ingest;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent.Params;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Information about an ingest processor
+ *
+ * @opensearch.internal
+ */
 public class ProcessorInfo implements Writeable, ToXContentObject, Comparable<ProcessorInfo> {
 
     private final String type;
diff --git a/server/src/main/java/org/opensearch/ingest/TrackingResultProcessor.java b/server/src/main/java/org/opensearch/ingest/TrackingResultProcessor.java
index efcb3b8d9840f..0362922617eee 100644
--- a/server/src/main/java/org/opensearch/ingest/TrackingResultProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/TrackingResultProcessor.java
@@ -44,6 +44,8 @@
 
 /**
  * Processor to be used within Simulate API to keep track of processors executed in pipeline.
+ *
+ * @opensearch.internal
  */
 public final class TrackingResultProcessor implements Processor {
 
diff --git a/server/src/main/java/org/opensearch/ingest/ValueSource.java b/server/src/main/java/org/opensearch/ingest/ValueSource.java
index c5936b0fa4a1a..0ef7c3373596d 100644
--- a/server/src/main/java/org/opensearch/ingest/ValueSource.java
+++ b/server/src/main/java/org/opensearch/ingest/ValueSource.java
@@ -49,6 +49,8 @@
 
 /**
  * Holds a value. If the value is requested a copy is made and optionally template snippets are resolved too.
+ *
+ * @opensearch.internal
  */
 public interface ValueSource {
 
@@ -99,6 +101,11 @@ static ValueSource wrap(Object value, ScriptService scriptService) {
         }
     }
 
+    /**
+     * A map value source.
+     *
+     * @opensearch.internal
+     */
     final class MapValue implements ValueSource {
 
         private final Map<ValueSource, ValueSource> map;
@@ -132,6 +139,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * A list value source.
+     *
+     * @opensearch.internal
+     */
     final class ListValue implements ValueSource {
 
         private final List<ValueSource> values;
@@ -165,6 +177,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * An object value source.
+     *
+     * @opensearch.internal
+     */
     final class ObjectValue implements ValueSource {
 
         private final Object value;
@@ -193,6 +210,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * A byte value source.
+     *
+     * @opensearch.internal
+     */
     final class ByteValue implements ValueSource {
 
         private final byte[] value;
@@ -222,6 +244,11 @@ public int hashCode() {
 
     }
 
+    /**
+     * A templated value.
+     *
+     * @opensearch.internal
+     */
     final class TemplatedValue implements ValueSource {
 
         private final TemplateScript.Factory template;
diff --git a/server/src/main/java/org/opensearch/ingest/WrappingProcessor.java b/server/src/main/java/org/opensearch/ingest/WrappingProcessor.java
index 33db293b510eb..b40ff7be3eb24 100644
--- a/server/src/main/java/org/opensearch/ingest/WrappingProcessor.java
+++ b/server/src/main/java/org/opensearch/ingest/WrappingProcessor.java
@@ -35,6 +35,8 @@
 /**
  * A srapping processor is one that encapsulates an inner processor, or a processor that the wrapped processor enacts upon. All processors
  * that contain an "inner" processor should implement this interface, such that the actual processor can be obtained.
+ *
+ * @opensearch.internal
  */
 public interface WrappingProcessor extends Processor {
 
diff --git a/server/src/main/java/org/opensearch/ingest/package-info.java b/server/src/main/java/org/opensearch/ingest/package-info.java
new file mode 100644
index 0000000000000..513d288495520
--- /dev/null
+++ b/server/src/main/java/org/opensearch/ingest/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Ingest Processor base package. */
+package org.opensearch.ingest;
diff --git a/server/src/main/java/org/opensearch/lucene/package-info.java b/server/src/main/java/org/opensearch/lucene/package-info.java
new file mode 100644
index 0000000000000..b56e64b670cbd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/lucene/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Package for OpenSearch Lucene Extensions. */
+package org.opensearch.lucene;
diff --git a/server/src/main/java/org/opensearch/lucene/queries/MinDocQuery.java b/server/src/main/java/org/opensearch/lucene/queries/MinDocQuery.java
index a7dbadb32ccf2..5c904d8a7770d 100644
--- a/server/src/main/java/org/opensearch/lucene/queries/MinDocQuery.java
+++ b/server/src/main/java/org/opensearch/lucene/queries/MinDocQuery.java
@@ -48,7 +48,10 @@
 import java.util.Objects;
 
 /** A {@link Query} that only matches documents that are greater than or equal
- *  to a configured doc ID. */
+ *  to a configured doc ID.
+ *
+ *  @opensearch.internal
+ */
 public final class MinDocQuery extends Query {
 
     // Matching documents depend on the sequence of segments that the index reader
@@ -83,7 +86,8 @@ public boolean equals(Object obj) {
     }
 
     @Override
-    public Query rewrite(IndexReader reader) throws IOException {
+    public Query rewrite(IndexSearcher searcher) throws IOException {
+        final IndexReader reader = searcher.getIndexReader();
         if (Objects.equals(reader.getContext().id(), readerId) == false) {
             return new MinDocQuery(minDoc, reader.getContext().id());
         }
diff --git a/server/src/main/java/org/opensearch/lucene/queries/SearchAfterSortedDocQuery.java b/server/src/main/java/org/opensearch/lucene/queries/SearchAfterSortedDocQuery.java
index 70cc73d2108cc..e417a2eaa7cf4 100644
--- a/server/src/main/java/org/opensearch/lucene/queries/SearchAfterSortedDocQuery.java
+++ b/server/src/main/java/org/opensearch/lucene/queries/SearchAfterSortedDocQuery.java
@@ -56,6 +56,7 @@
 /**
  * A {@link Query} that only matches documents that are greater than the provided {@link FieldDoc}.
  * This works only if the index is sorted according to the given search {@link Sort}.
+ * @opensearch.internal
  */
 public class SearchAfterSortedDocQuery extends Query {
     private final Sort sort;
diff --git a/server/src/main/java/org/opensearch/lucene/queries/package-info.java b/server/src/main/java/org/opensearch/lucene/queries/package-info.java
new file mode 100644
index 0000000000000..4fee9a059b80b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/lucene/queries/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OpenSearch specific lucene query implementations. */
+package org.opensearch.lucene.queries;
diff --git a/server/src/main/java/org/opensearch/monitor/MonitorService.java b/server/src/main/java/org/opensearch/monitor/MonitorService.java
index 85a96a16ab912..ad02b18366b98 100644
--- a/server/src/main/java/org/opensearch/monitor/MonitorService.java
+++ b/server/src/main/java/org/opensearch/monitor/MonitorService.java
@@ -32,9 +32,10 @@
 
 package org.opensearch.monitor;
 
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.store.remote.filecache.FileCache;
 import org.opensearch.monitor.fs.FsService;
 import org.opensearch.monitor.jvm.JvmGcMonitorService;
 import org.opensearch.monitor.jvm.JvmService;
@@ -44,6 +45,11 @@
 
 import java.io.IOException;
 
+/**
+ * The resource monitoring service
+ *
+ * @opensearch.internal
+ */
 public class MonitorService extends AbstractLifecycleComponent {
 
     private final JvmGcMonitorService jvmGcMonitorService;
@@ -52,12 +58,13 @@ public class MonitorService extends AbstractLifecycleComponent {
     private final JvmService jvmService;
     private final FsService fsService;
 
-    public MonitorService(Settings settings, NodeEnvironment nodeEnvironment, ThreadPool threadPool) throws IOException {
+    public MonitorService(Settings settings, NodeEnvironment nodeEnvironment, ThreadPool threadPool, FileCache fileCache)
+        throws IOException {
         this.jvmGcMonitorService = new JvmGcMonitorService(settings, threadPool);
         this.osService = new OsService(settings);
         this.processService = new ProcessService(settings);
         this.jvmService = new JvmService(settings);
-        this.fsService = new FsService(settings, nodeEnvironment);
+        this.fsService = new FsService(settings, nodeEnvironment, fileCache);
     }
 
     public OsService osService() {
diff --git a/server/src/main/java/org/opensearch/monitor/NodeHealthService.java b/server/src/main/java/org/opensearch/monitor/NodeHealthService.java
index e9e8cf33dcbd5..54d64e8c83b28 100644
--- a/server/src/main/java/org/opensearch/monitor/NodeHealthService.java
+++ b/server/src/main/java/org/opensearch/monitor/NodeHealthService.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.monitor;
 
+/**
+ * The service for monitoring node health
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface NodeHealthService {
 
diff --git a/server/src/main/java/org/opensearch/monitor/Probes.java b/server/src/main/java/org/opensearch/monitor/Probes.java
index 12f0e67be32c5..08f9eb7c2c376 100644
--- a/server/src/main/java/org/opensearch/monitor/Probes.java
+++ b/server/src/main/java/org/opensearch/monitor/Probes.java
@@ -35,6 +35,11 @@
 import java.lang.management.OperatingSystemMXBean;
 import java.lang.reflect.Method;
 
+/**
+ * Probes the various resources
+ *
+ * @opensearch.internal
+ */
 public class Probes {
     public static short getLoadAndScaleToPercent(Method method, OperatingSystemMXBean osMxBean) {
         if (method != null) {
diff --git a/server/src/main/java/org/opensearch/monitor/StatusInfo.java b/server/src/main/java/org/opensearch/monitor/StatusInfo.java
index b1d8528e8822f..d6f8aa060385d 100644
--- a/server/src/main/java/org/opensearch/monitor/StatusInfo.java
+++ b/server/src/main/java/org/opensearch/monitor/StatusInfo.java
@@ -35,9 +35,16 @@
 /**
  * Class that represents the Health status for a node as determined by {@link NodeHealthService} and provides additional
  * info explaining the reasons
+ *
+ * @opensearch.internal
  */
 public class StatusInfo {
 
+    /**
+     * The status.
+     *
+     * @opensearch.internal
+     */
     public enum Status {
         HEALTHY,
         UNHEALTHY
diff --git a/server/src/main/java/org/opensearch/monitor/fs/FsHealthService.java b/server/src/main/java/org/opensearch/monitor/fs/FsHealthService.java
index a1f526a3a1bd8..4b0a79783885f 100644
--- a/server/src/main/java/org/opensearch/monitor/fs/FsHealthService.java
+++ b/server/src/main/java/org/opensearch/monitor/fs/FsHealthService.java
@@ -35,15 +35,14 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
@@ -68,6 +67,8 @@
 /**
  * Runs periodically and attempts to create a temp file to see if the filesystem is writable. If not then it marks the
  * path as unhealthy.
+ *
+ * @opensearch.internal
  */
 public class FsHealthService extends AbstractLifecycleComponent implements NodeHealthService {
 
diff --git a/server/src/main/java/org/opensearch/monitor/fs/FsInfo.java b/server/src/main/java/org/opensearch/monitor/fs/FsInfo.java
index 5a17cb05ef225..cbde61925d834 100644
--- a/server/src/main/java/org/opensearch/monitor/fs/FsInfo.java
+++ b/server/src/main/java/org/opensearch/monitor/fs/FsInfo.java
@@ -33,15 +33,16 @@
 package org.opensearch.monitor.fs;
 
 import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
 import org.opensearch.cluster.DiskUsage;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -49,8 +50,18 @@
 import java.util.Iterator;
 import java.util.Set;
 
+/**
+ * FileSystem information
+ *
+ * @opensearch.internal
+ */
 public class FsInfo implements Iterable<FsInfo.Path>, Writeable, ToXContentFragment {
 
+    /**
+     * Path for the file system
+     *
+     * @opensearch.internal
+     */
     public static class Path implements Writeable, ToXContentObject {
 
         String path;
@@ -62,6 +73,8 @@ public static class Path implements Writeable, ToXContentObject {
         long total = -1;
         long free = -1;
         long available = -1;
+        long fileCacheReserved = -1;
+        long fileCacheUtilized = 0;
 
         public Path() {}
 
@@ -83,6 +96,10 @@ public Path(StreamInput in) throws IOException {
             total = in.readLong();
             free = in.readLong();
             available = in.readLong();
+            if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+                fileCacheReserved = in.readLong();
+                fileCacheUtilized = in.readLong();
+            }
         }
 
         @Override
@@ -93,6 +110,10 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(total);
             out.writeLong(free);
             out.writeLong(available);
+            if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+                out.writeLong(fileCacheReserved);
+                out.writeLong(fileCacheUtilized);
+            }
         }
 
         public String getPath() {
@@ -119,6 +140,14 @@ public ByteSizeValue getAvailable() {
             return new ByteSizeValue(available);
         }
 
+        public ByteSizeValue getFileCacheReserved() {
+            return new ByteSizeValue(fileCacheReserved);
+        }
+
+        public ByteSizeValue getFileCacheUtilized() {
+            return new ByteSizeValue(fileCacheUtilized);
+        }
+
         private long addLong(long current, long other) {
             if (current == -1 && other == -1) {
                 return 0;
@@ -135,6 +164,8 @@ private long addLong(long current, long other) {
         public void add(Path path) {
             total = FsProbe.adjustForHugeFilesystems(addLong(total, path.total));
             free = FsProbe.adjustForHugeFilesystems(addLong(free, path.free));
+            fileCacheReserved = FsProbe.adjustForHugeFilesystems(addLong(fileCacheReserved, path.fileCacheReserved));
+            fileCacheUtilized = FsProbe.adjustForHugeFilesystems(addLong(fileCacheUtilized, path.fileCacheUtilized));
             available = FsProbe.adjustForHugeFilesystems(addLong(available, path.available));
         }
 
@@ -148,6 +179,10 @@ static final class Fields {
             static final String FREE_IN_BYTES = "free_in_bytes";
             static final String AVAILABLE = "available";
             static final String AVAILABLE_IN_BYTES = "available_in_bytes";
+            static final String CACHE_RESERVED = "cache_reserved";
+            static final String CACHE_RESERVED_IN_BYTES = "cache_reserved_in_bytes";
+            static final String CACHE_UTILIZED = "cache_utilized";
+            static final String CACHE_UTILIZED_IN_BYTES = "cache_utilized_in_bytes";
         }
 
         @Override
@@ -172,12 +207,23 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             if (available != -1) {
                 builder.humanReadableField(Fields.AVAILABLE_IN_BYTES, Fields.AVAILABLE, getAvailable());
             }
+            if (fileCacheReserved != -1) {
+                builder.humanReadableField(Fields.CACHE_RESERVED_IN_BYTES, Fields.CACHE_RESERVED, getFileCacheReserved());
+            }
+            if (fileCacheReserved != 0) {
+                builder.humanReadableField(Fields.CACHE_UTILIZED, Fields.CACHE_UTILIZED_IN_BYTES, getFileCacheUtilized());
+            }
 
             builder.endObject();
             return builder;
         }
     }
 
+    /**
+     * The device status.
+     *
+     * @opensearch.internal
+     */
     public static class DeviceStats implements Writeable, ToXContentFragment {
 
         final int majorDeviceNumber;
@@ -315,6 +361,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     }
 
+    /**
+     * The I/O statistics.
+     *
+     * @opensearch.internal
+     */
     public static class IoStats implements Writeable, ToXContentFragment {
 
         private static final String OPERATIONS = "operations";
diff --git a/server/src/main/java/org/opensearch/monitor/fs/FsProbe.java b/server/src/main/java/org/opensearch/monitor/fs/FsProbe.java
index 7fd5c66895db6..f39de883536be 100644
--- a/server/src/main/java/org/opensearch/monitor/fs/FsProbe.java
+++ b/server/src/main/java/org/opensearch/monitor/fs/FsProbe.java
@@ -39,8 +39,10 @@
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.PathUtils;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeEnvironment.NodePath;
+import org.opensearch.index.store.remote.filecache.FileCache;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -51,14 +53,21 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * FileSystem probe
+ *
+ * @opensearch.internal
+ */
 public class FsProbe {
 
     private static final Logger logger = LogManager.getLogger(FsProbe.class);
 
     private final NodeEnvironment nodeEnv;
+    private final FileCache fileCache;
 
-    public FsProbe(NodeEnvironment nodeEnv) {
+    public FsProbe(NodeEnvironment nodeEnv, FileCache fileCache) {
         this.nodeEnv = nodeEnv;
+        this.fileCache = fileCache;
     }
 
     public FsInfo stats(FsInfo previous) throws IOException {
@@ -69,13 +78,18 @@ public FsInfo stats(FsInfo previous) throws IOException {
         FsInfo.Path[] paths = new FsInfo.Path[dataLocations.length];
         for (int i = 0; i < dataLocations.length; i++) {
             paths[i] = getFSInfo(dataLocations[i]);
+            if (fileCache != null && dataLocations[i].fileCacheReservedSize != ByteSizeValue.ZERO) {
+                paths[i].fileCacheReserved = adjustForHugeFilesystems(dataLocations[i].fileCacheReservedSize.getBytes());
+                paths[i].fileCacheUtilized = adjustForHugeFilesystems(fileCache.usage().usage());
+                paths[i].available -= (paths[i].fileCacheReserved - paths[i].fileCacheUtilized);
+            }
         }
         FsInfo.IoStats ioStats = null;
         if (Constants.LINUX) {
             Set<Tuple<Integer, Integer>> devicesNumbers = new HashSet<>();
-            for (int i = 0; i < dataLocations.length; i++) {
-                if (dataLocations[i].majorDeviceNumber != -1 && dataLocations[i].minorDeviceNumber != -1) {
-                    devicesNumbers.add(Tuple.tuple(dataLocations[i].majorDeviceNumber, dataLocations[i].minorDeviceNumber));
+            for (NodePath dataLocation : dataLocations) {
+                if (dataLocation.majorDeviceNumber != -1 && dataLocation.minorDeviceNumber != -1) {
+                    devicesNumbers.add(Tuple.tuple(dataLocation.majorDeviceNumber, dataLocation.minorDeviceNumber));
                 }
             }
             ioStats = ioStats(devicesNumbers, previous);
@@ -162,6 +176,7 @@ public static FsInfo.Path getFSInfo(NodePath nodePath) throws IOException {
         fsPath.total = adjustForHugeFilesystems(nodePath.fileStore.getTotalSpace());
         fsPath.free = adjustForHugeFilesystems(nodePath.fileStore.getUnallocatedSpace());
         fsPath.available = adjustForHugeFilesystems(nodePath.fileStore.getUsableSpace());
+        fsPath.fileCacheReserved = adjustForHugeFilesystems(nodePath.fileCacheReservedSize.getBytes());
         fsPath.type = nodePath.fileStore.type();
         fsPath.mount = nodePath.fileStore.toString();
         return fsPath;
diff --git a/server/src/main/java/org/opensearch/monitor/fs/FsService.java b/server/src/main/java/org/opensearch/monitor/fs/FsService.java
index 837b7dbbe4fa2..20ea4bd1448ad 100644
--- a/server/src/main/java/org/opensearch/monitor/fs/FsService.java
+++ b/server/src/main/java/org/opensearch/monitor/fs/FsService.java
@@ -40,10 +40,16 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.SingleObjectCache;
 import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.store.remote.filecache.FileCache;
 
 import java.io.IOException;
 import java.util.function.Supplier;
 
+/**
+ * FileSystem service
+ *
+ * @opensearch.internal
+ */
 public class FsService {
 
     private static final Logger logger = LogManager.getLogger(FsService.class);
@@ -64,8 +70,8 @@ public class FsService {
         Property.NodeScope
     );
 
-    public FsService(final Settings settings, final NodeEnvironment nodeEnvironment) {
-        final FsProbe probe = new FsProbe(nodeEnvironment);
+    public FsService(final Settings settings, final NodeEnvironment nodeEnvironment, FileCache fileCache) {
+        final FsProbe probe = new FsProbe(nodeEnvironment, fileCache);
         final FsInfo initialValue = stats(probe, null);
         if (ALWAYS_REFRESH_SETTING.get(settings)) {
             assert REFRESH_INTERVAL_SETTING.exists(settings) == false;
diff --git a/server/src/main/java/org/opensearch/monitor/fs/package-info.java b/server/src/main/java/org/opensearch/monitor/fs/package-info.java
new file mode 100644
index 0000000000000..bfd99560f8eb6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/monitor/fs/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** FileSystem monitoring package. For _cat APIs. */
+package org.opensearch.monitor.fs;
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/DeadlockAnalyzer.java b/server/src/main/java/org/opensearch/monitor/jvm/DeadlockAnalyzer.java
index 22705d8d163b8..12d749a2b9102 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/DeadlockAnalyzer.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/DeadlockAnalyzer.java
@@ -45,6 +45,11 @@
 import static java.util.Collections.unmodifiableMap;
 import static java.util.Collections.unmodifiableSet;
 
+/**
+ * Analyzes Operating System deadlocks
+ *
+ * @opensearch.internal
+ */
 public class DeadlockAnalyzer {
 
     private static final Deadlock NULL_RESULT[] = new Deadlock[0];
@@ -135,6 +140,11 @@ private Map<Long, ThreadInfo> createThreadInfoMap(long threadIds[]) {
         return unmodifiableMap(threadInfoMap);
     }
 
+    /**
+     * The deadlock being analyzed.
+     *
+     * @opensearch.internal
+     */
     public static class Deadlock {
         private final ThreadInfo members[];
         private final String description;
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/GcNames.java b/server/src/main/java/org/opensearch/monitor/jvm/GcNames.java
index 3b464314b7ceb..d6b77186e021c 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/GcNames.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/GcNames.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.monitor.jvm;
 
+/**
+ * Simple utility class for human readable GC names
+ *
+ * @opensearch.internal
+ */
 public class GcNames {
 
     public static final String YOUNG = "young";
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/HotThreads.java b/server/src/main/java/org/opensearch/monitor/jvm/HotThreads.java
index 8e91a7258aabd..b5963d8ebd889 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/HotThreads.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/HotThreads.java
@@ -51,6 +51,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.ToLongFunction;
 
+/**
+ * Monitors hot threads
+ *
+ * @opensearch.internal
+ */
 public class HotThreads {
 
     private static final Object mutex = new Object();
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/JvmGcMonitorService.java b/server/src/main/java/org/opensearch/monitor/jvm/JvmGcMonitorService.java
index 5020cbec36e44..6481c21ffea48 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/JvmGcMonitorService.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/JvmGcMonitorService.java
@@ -34,12 +34,12 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.monitor.jvm.JvmStats.GarbageCollector;
 import org.opensearch.threadpool.Scheduler.Cancellable;
 import org.opensearch.threadpool.ThreadPool;
@@ -54,6 +54,11 @@
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * Service to monitor garbage collection
+ *
+ * @opensearch.internal
+ */
 public class JvmGcMonitorService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(JvmGcMonitorService.class);
 
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/JvmInfo.java b/server/src/main/java/org/opensearch/monitor/jvm/JvmInfo.java
index ed6d21869acd7..447d32081cedf 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/JvmInfo.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/JvmInfo.java
@@ -37,12 +37,12 @@
 import org.opensearch.common.Booleans;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.lang.management.GarbageCollectorMXBean;
@@ -57,6 +57,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Holds information about the JVM
+ *
+ * @opensearch.internal
+ */
 public class JvmInfo implements ReportingService.Info {
 
     private static JvmInfo INSTANCE;
@@ -167,7 +172,7 @@ public class JvmInfo implements ReportingService.Info {
         }
 
         final boolean bundledJdk = Booleans.parseBoolean(System.getProperty("opensearch.bundled_jdk", Boolean.FALSE.toString()));
-        final Boolean usingBundledJdk = bundledJdk ? usingBundledJdk() : null;
+        final Boolean usingBundledJdkOrJre = bundledJdk ? usingBundledJdkOrJre() : null;
 
         INSTANCE = new JvmInfo(
             JvmPid.getPid(),
@@ -176,7 +181,7 @@ public class JvmInfo implements ReportingService.Info {
             runtimeMXBean.getVmVersion(),
             runtimeMXBean.getVmVendor(),
             bundledJdk,
-            usingBundledJdk,
+            usingBundledJdkOrJre,
             runtimeMXBean.getStartTime(),
             configuredInitialHeapSize,
             configuredMaxHeapSize,
@@ -197,7 +202,7 @@ public class JvmInfo implements ReportingService.Info {
     }
 
     @SuppressForbidden(reason = "PathUtils#get")
-    private static boolean usingBundledJdk() {
+    private static boolean usingBundledJdkOrJre() {
         /*
          * We are using the bundled JDK if java.home is the jdk sub-directory of our working directory. This is because we always set
          * the working directory of Elasticsearch to home, and the bundled JDK is in the jdk sub-directory there.
@@ -207,7 +212,8 @@ private static boolean usingBundledJdk() {
         if (Constants.MAC_OS_X) {
             return PathUtils.get(javaHome).equals(PathUtils.get(userDir).resolve("jdk.app/Contents/Home").toAbsolutePath());
         } else {
-            return PathUtils.get(javaHome).equals(PathUtils.get(userDir).resolve("jdk").toAbsolutePath());
+            return PathUtils.get(javaHome).equals(PathUtils.get(userDir).resolve("jre").toAbsolutePath())
+                || PathUtils.get(javaHome).equals(PathUtils.get(userDir).resolve("jdk").toAbsolutePath());
         }
     }
 
@@ -594,6 +600,11 @@ static final class Fields {
         static final String INPUT_ARGUMENTS = "input_arguments";
     }
 
+    /**
+     * Memory information.
+     *
+     * @opensearch.internal
+     */
     public static class Mem implements Writeable {
 
         private final long heapInit;
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/JvmPid.java b/server/src/main/java/org/opensearch/monitor/jvm/JvmPid.java
index bf9b5f6fe4f3f..928257af71aa5 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/JvmPid.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/JvmPid.java
@@ -32,31 +32,15 @@
 
 package org.opensearch.monitor.jvm;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.message.ParameterizedMessage;
-
-import java.lang.management.ManagementFactory;
-
+/**
+ * JVM Process ID
+ *
+ * @opensearch.internal
+ */
 class JvmPid {
 
-    private static final long PID;
-
     static long getPid() {
-        return PID;
-    }
-
-    static {
-        PID = initializePid();
-    }
-
-    private static long initializePid() {
-        final String name = ManagementFactory.getRuntimeMXBean().getName();
-        try {
-            return Long.parseLong(name.split("@")[0]);
-        } catch (final NumberFormatException e) {
-            LogManager.getLogger(JvmPid.class).debug(new ParameterizedMessage("failed parsing PID from [{}]", name), e);
-            return -1;
-        }
+        return ProcessHandle.current().pid();
     }
 
 }
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/JvmService.java b/server/src/main/java/org/opensearch/monitor/jvm/JvmService.java
index edf8e47317114..548a5fb3650c1 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/JvmService.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/JvmService.java
@@ -38,8 +38,13 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.service.ReportingService;
 
+/**
+ * Service for monitoring the JVM
+ *
+ * @opensearch.internal
+ */
 public class JvmService implements ReportingService<JvmInfo> {
 
     private static final Logger logger = LogManager.getLogger(JvmService.class);
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/JvmStats.java b/server/src/main/java/org/opensearch/monitor/jvm/JvmStats.java
index e8fa037f3a4d7..651ef650d14fb 100644
--- a/server/src/main/java/org/opensearch/monitor/jvm/JvmStats.java
+++ b/server/src/main/java/org/opensearch/monitor/jvm/JvmStats.java
@@ -33,13 +33,13 @@
 package org.opensearch.monitor.jvm;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.lang.management.BufferPoolMXBean;
@@ -58,6 +58,11 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Holds JVM statistics
+ *
+ * @opensearch.internal
+ */
 public class JvmStats implements Writeable, ToXContentFragment {
 
     private static final RuntimeMXBean runtimeMXBean;
@@ -366,6 +371,11 @@ static final class Fields {
         static final String TOTAL_UNLOADED_COUNT = "total_unloaded_count";
     }
 
+    /**
+     * Garbage collector references.
+     *
+     * @opensearch.internal
+     */
     public static class GarbageCollectors implements Writeable, Iterable<GarbageCollector> {
 
         private final GarbageCollector[] collectors;
@@ -393,6 +403,11 @@ public Iterator<GarbageCollector> iterator() {
         }
     }
 
+    /**
+     * The garbage collector.
+     *
+     * @opensearch.internal
+     */
     public static class GarbageCollector implements Writeable {
 
         private final String name;
@@ -431,6 +446,11 @@ public TimeValue getCollectionTime() {
         }
     }
 
+    /**
+     * Thread information.
+     *
+     * @opensearch.internal
+     */
     public static class Threads implements Writeable {
 
         private final int count;
@@ -465,6 +485,8 @@ public int getPeakCount() {
      * Stores the memory usage after the Java virtual machine
      * most recently expended effort in recycling unused objects
      * in particular memory pool.
+     *
+     * @opensearch.internal
      */
     public static class MemoryPoolGcStats implements Writeable {
 
@@ -503,6 +525,11 @@ public short getUsagePercent() {
         }
     }
 
+    /**
+     * A memory pool.
+     *
+     * @opensearch.internal
+     */
     public static class MemoryPool implements Writeable {
 
         private final String name;
@@ -574,6 +601,11 @@ public MemoryPoolGcStats getLastGcStats() {
         }
     }
 
+    /**
+     * Memory data.
+     *
+     * @opensearch.internal
+     */
     public static class Mem implements Writeable, Iterable<MemoryPool> {
 
         private final long heapCommitted;
@@ -650,6 +682,11 @@ public ByteSizeValue getNonHeapUsed() {
         }
     }
 
+    /**
+     * A buffer pool.
+     *
+     * @opensearch.internal
+     */
     public static class BufferPool implements Writeable {
 
         private final String name;
@@ -696,6 +733,11 @@ public ByteSizeValue getUsed() {
         }
     }
 
+    /**
+     * Class information.
+     *
+     * @opensearch.internal
+     */
     public static class Classes implements Writeable {
 
         private final long loadedClassCount;
diff --git a/server/src/main/java/org/opensearch/monitor/jvm/package-info.java b/server/src/main/java/org/opensearch/monitor/jvm/package-info.java
new file mode 100644
index 0000000000000..bff07e3886af2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/monitor/jvm/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** JVM Monitoring base package. For _cat APIs. */
+package org.opensearch.monitor.jvm;
diff --git a/server/src/main/java/org/opensearch/monitor/os/OsInfo.java b/server/src/main/java/org/opensearch/monitor/os/OsInfo.java
index 2dacb88b4b254..98bad3f406405 100644
--- a/server/src/main/java/org/opensearch/monitor/os/OsInfo.java
+++ b/server/src/main/java/org/opensearch/monitor/os/OsInfo.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.monitor.os;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Holds Operating System Information
+ *
+ * @opensearch.internal
+ */
 public class OsInfo implements ReportingService.Info {
 
     private final long refreshInterval;
diff --git a/server/src/main/java/org/opensearch/monitor/os/OsProbe.java b/server/src/main/java/org/opensearch/monitor/os/OsProbe.java
index eda86c49539dd..98229941252ba 100644
--- a/server/src/main/java/org/opensearch/monitor/os/OsProbe.java
+++ b/server/src/main/java/org/opensearch/monitor/os/OsProbe.java
@@ -74,6 +74,8 @@
  * - An error case retrieving these values from a linux kernel
  * - A non-standard libc implementation not implementing the required values
  * For a more exhaustive explanation, see https://github.com/elastic/elasticsearch/pull/42725
+ *
+ * @opensearch.internal
  */
 public class OsProbe {
 
diff --git a/server/src/main/java/org/opensearch/monitor/os/OsService.java b/server/src/main/java/org/opensearch/monitor/os/OsService.java
index 344a5ccf5f849..5ae2f4f990252 100644
--- a/server/src/main/java/org/opensearch/monitor/os/OsService.java
+++ b/server/src/main/java/org/opensearch/monitor/os/OsService.java
@@ -40,10 +40,15 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.SingleObjectCache;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.service.ReportingService;
 
 import java.io.IOException;
 
+/**
+ * Service for the Operating System
+ *
+ * @opensearch.internal
+ */
 public class OsService implements ReportingService<OsInfo> {
 
     private static final Logger logger = LogManager.getLogger(OsService.class);
diff --git a/server/src/main/java/org/opensearch/monitor/os/OsStats.java b/server/src/main/java/org/opensearch/monitor/os/OsStats.java
index cc9dec8d2727b..697b86c6ba55c 100644
--- a/server/src/main/java/org/opensearch/monitor/os/OsStats.java
+++ b/server/src/main/java/org/opensearch/monitor/os/OsStats.java
@@ -34,17 +34,22 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Objects;
 
+/**
+ * Holds stats for the Operating System
+ *
+ * @opensearch.internal
+ */
 public class OsStats implements Writeable, ToXContentFragment {
 
     private final long timestamp;
@@ -135,6 +140,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * CPU Information.
+     *
+     * @opensearch.internal
+     */
     public static class Cpu implements Writeable, ToXContentFragment {
 
         private final short percent;
@@ -195,6 +205,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * Swap information.
+     *
+     * @opensearch.internal
+     */
     public static class Swap implements Writeable, ToXContentFragment {
 
         private static final Logger logger = LogManager.getLogger(Swap.class);
@@ -258,6 +273,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         }
     }
 
+    /**
+     * OS Memory information.
+     *
+     * @opensearch.internal
+     */
     public static class Mem implements Writeable, ToXContentFragment {
 
         private static final Logger logger = LogManager.getLogger(Mem.class);
@@ -332,6 +352,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     /**
      * Encapsulates basic cgroup statistics.
+     *
+     * @opensearch.internal
      */
     public static class Cgroup implements Writeable, ToXContentFragment {
 
@@ -523,6 +545,8 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
 
         /**
          * Encapsulates CPU time statistics.
+         *
+         * @opensearch.internal
          */
         public static class CpuStat implements Writeable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/monitor/os/package-info.java b/server/src/main/java/org/opensearch/monitor/os/package-info.java
new file mode 100644
index 0000000000000..73a912ead3fd5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/monitor/os/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** OperatingSystem monitoring base package. For _cat APIs. */
+package org.opensearch.monitor.os;
diff --git a/server/src/main/java/org/opensearch/monitor/process/ProcessInfo.java b/server/src/main/java/org/opensearch/monitor/process/ProcessInfo.java
index 073309b61926a..d2090e897e851 100644
--- a/server/src/main/java/org/opensearch/monitor/process/ProcessInfo.java
+++ b/server/src/main/java/org/opensearch/monitor/process/ProcessInfo.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.monitor.process;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Holds information for monitoring the process
+ *
+ * @opensearch.internal
+ */
 public class ProcessInfo implements ReportingService.Info {
 
     private final long refreshInterval;
diff --git a/server/src/main/java/org/opensearch/monitor/process/ProcessProbe.java b/server/src/main/java/org/opensearch/monitor/process/ProcessProbe.java
index 09faae6bcaefa..c2f83003d2c04 100644
--- a/server/src/main/java/org/opensearch/monitor/process/ProcessProbe.java
+++ b/server/src/main/java/org/opensearch/monitor/process/ProcessProbe.java
@@ -41,6 +41,11 @@
 
 import static org.opensearch.monitor.jvm.JvmInfo.jvmInfo;
 
+/**
+ * Probes the process
+ *
+ * @opensearch.internal
+ */
 public class ProcessProbe {
 
     private static final OperatingSystemMXBean osMxBean = ManagementFactory.getOperatingSystemMXBean();
diff --git a/server/src/main/java/org/opensearch/monitor/process/ProcessService.java b/server/src/main/java/org/opensearch/monitor/process/ProcessService.java
index c60d4435b46b0..c659724edf24f 100644
--- a/server/src/main/java/org/opensearch/monitor/process/ProcessService.java
+++ b/server/src/main/java/org/opensearch/monitor/process/ProcessService.java
@@ -39,8 +39,13 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.SingleObjectCache;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.service.ReportingService;
 
+/**
+ * The service for the process
+ *
+ * @opensearch.internal
+ */
 public final class ProcessService implements ReportingService<ProcessInfo> {
 
     private static final Logger logger = LogManager.getLogger(ProcessService.class);
diff --git a/server/src/main/java/org/opensearch/monitor/process/ProcessStats.java b/server/src/main/java/org/opensearch/monitor/process/ProcessStats.java
index 6fce06ac5a93d..a931f5efdaed2 100644
--- a/server/src/main/java/org/opensearch/monitor/process/ProcessStats.java
+++ b/server/src/main/java/org/opensearch/monitor/process/ProcessStats.java
@@ -32,17 +32,21 @@
 
 package org.opensearch.monitor.process;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent.Params;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Holds stats for the process
+ *
+ * @opensearch.internal
+ */
 public class ProcessStats implements Writeable, ToXContentFragment {
 
     private final long timestamp;
@@ -133,6 +137,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Process memory information.
+     *
+     * @opensearch.internal
+     */
     public static class Mem implements Writeable {
 
         private final long totalVirtual;
@@ -155,6 +164,11 @@ public ByteSizeValue getTotalVirtual() {
         }
     }
 
+    /**
+     * Process CPU information.
+     *
+     * @opensearch.internal
+     */
     public static class Cpu implements Writeable {
 
         private final short percent;
diff --git a/server/src/main/java/org/opensearch/monitor/process/package-info.java b/server/src/main/java/org/opensearch/monitor/process/package-info.java
new file mode 100644
index 0000000000000..c99241bf534ba
--- /dev/null
+++ b/server/src/main/java/org/opensearch/monitor/process/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Process monitoring base package. For _cat APIs. */
+package org.opensearch.monitor.process;
diff --git a/server/src/main/java/org/opensearch/node/AdaptiveSelectionStats.java b/server/src/main/java/org/opensearch/node/AdaptiveSelectionStats.java
index 5102d78523abe..0241f5f6191d4 100644
--- a/server/src/main/java/org/opensearch/node/AdaptiveSelectionStats.java
+++ b/server/src/main/java/org/opensearch/node/AdaptiveSelectionStats.java
@@ -32,14 +32,13 @@
 
 package org.opensearch.node;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent.Params;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -52,6 +51,8 @@
  * Class representing statistics about adaptive replica selection. This includes
  * EWMA of queue size, service time, and response time, as well as outgoing
  * searches to each node and the "rank" based on the ARS formula.
+ *
+ * @opensearch.internal
  */
 public class AdaptiveSelectionStats implements Writeable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/node/InternalSettingsPreparer.java b/server/src/main/java/org/opensearch/node/InternalSettingsPreparer.java
index 0879b498ac41c..ed1375bf7f474 100644
--- a/server/src/main/java/org/opensearch/node/InternalSettingsPreparer.java
+++ b/server/src/main/java/org/opensearch/node/InternalSettingsPreparer.java
@@ -32,6 +32,12 @@
 
 package org.opensearch.node;
 
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsException;
+import org.opensearch.env.Environment;
+
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -39,15 +45,14 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Supplier;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
-import org.opensearch.Version;
-import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.settings.SettingsException;
-import org.opensearch.env.Environment;
-
+/**
+ * Prepares internal settings
+ *
+ * @opensearch.internal
+ */
 public class InternalSettingsPreparer {
 
     private static final String SECRET_PROMPT_VALUE = "${prompt.secret}";
diff --git a/server/src/main/java/org/opensearch/node/Node.java b/server/src/main/java/org/opensearch/node/Node.java
index 6368e097f6a14..4cd7caae29da0 100644
--- a/server/src/main/java/org/opensearch/node/Node.java
+++ b/server/src/main/java/org/opensearch/node/Node.java
@@ -35,19 +35,18 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.index.IndexingPressureService;
-import org.opensearch.watcher.ResourceWatcherService;
-import org.opensearch.Assertions;
 import org.opensearch.Build;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
 import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.snapshots.status.TransportNodesSnapshotsStatus;
 import org.opensearch.action.search.SearchExecutionStatsCollector;
 import org.opensearch.action.search.SearchPhaseController;
+import org.opensearch.action.search.SearchRequestStats;
 import org.opensearch.action.search.SearchTransportService;
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.action.update.UpdateHelper;
@@ -63,6 +62,7 @@
 import org.opensearch.cluster.InternalClusterInfoService;
 import org.opensearch.cluster.NodeConnectionsService;
 import org.opensearch.cluster.action.index.MappingUpdatedAction;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
 import org.opensearch.cluster.metadata.AliasValidator;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.cluster.metadata.Metadata;
@@ -75,18 +75,18 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.routing.BatchedRerouteService;
 import org.opensearch.cluster.routing.RerouteService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.DiskThresholdMonitor;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.StopWatch;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleComponent;
 import org.opensearch.common.inject.Injector;
 import org.opensearch.common.inject.Key;
 import org.opensearch.common.inject.Module;
 import org.opensearch.common.inject.ModulesBuilder;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.logging.HeaderWarning;
 import org.opensearch.common.logging.NodeAndClusterIdStateListener;
@@ -99,29 +99,51 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.SettingUpgrader;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsException;
 import org.opensearch.common.settings.SettingsModule;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.crypto.CryptoHandlerRegistry;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.extensions.NoopExtensionsManager;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.gateway.GatewayModule;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.gateway.MetaStateService;
 import org.opensearch.gateway.PersistedClusterStateService;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
 import org.opensearch.http.HttpServerTransport;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.analysis.AnalysisRegistry;
 import org.opensearch.index.engine.EngineFactory;
+import org.opensearch.index.recovery.RemoteStoreRestoreService;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheCleaner;
+import org.opensearch.index.store.remote.filecache.FileCacheFactory;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
@@ -129,18 +151,22 @@
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.indices.breaker.BreakerSettings;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.recovery.PeerRecoverySourceService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationSourceService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
 import org.opensearch.indices.store.IndicesStore;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.monitor.MonitorService;
 import org.opensearch.monitor.fs.FsHealthService;
+import org.opensearch.monitor.fs.FsInfo;
+import org.opensearch.monitor.fs.FsProbe;
 import org.opensearch.monitor.jvm.JvmInfo;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.persistent.PersistentTasksClusterService;
 import org.opensearch.persistent.PersistentTasksExecutor;
 import org.opensearch.persistent.PersistentTasksExecutorRegistry;
@@ -149,8 +175,12 @@
 import org.opensearch.plugins.AnalysisPlugin;
 import org.opensearch.plugins.CircuitBreakerPlugin;
 import org.opensearch.plugins.ClusterPlugin;
+import org.opensearch.plugins.CryptoKeyProviderPlugin;
+import org.opensearch.plugins.CryptoPlugin;
 import org.opensearch.plugins.DiscoveryPlugin;
 import org.opensearch.plugins.EnginePlugin;
+import org.opensearch.plugins.ExtensionAwarePlugin;
+import org.opensearch.plugins.IdentityPlugin;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.plugins.MapperPlugin;
@@ -161,8 +191,10 @@
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.plugins.RepositoryPlugin;
 import org.opensearch.plugins.ScriptPlugin;
+import org.opensearch.plugins.SearchPipelinePlugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.plugins.SystemIndexPlugin;
+import org.opensearch.plugins.TelemetryPlugin;
 import org.opensearch.repositories.RepositoriesModule;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.rest.RestController;
@@ -170,10 +202,14 @@
 import org.opensearch.script.ScriptEngine;
 import org.opensearch.script.ScriptModule;
 import org.opensearch.script.ScriptService;
+import org.opensearch.search.SearchBootstrapSettings;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.aggregations.support.AggregationUsageService;
+import org.opensearch.search.backpressure.SearchBackpressureService;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
 import org.opensearch.search.fetch.FetchPhase;
+import org.opensearch.search.pipeline.SearchPipelineService;
 import org.opensearch.search.query.QueryPhase;
 import org.opensearch.snapshots.InternalSnapshotsInfoService;
 import org.opensearch.snapshots.RestoreService;
@@ -181,17 +217,32 @@
 import org.opensearch.snapshots.SnapshotsInfoService;
 import org.opensearch.snapshots.SnapshotsService;
 import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellationMonitoringService;
+import org.opensearch.tasks.TaskCancellationMonitoringSettings;
 import org.opensearch.tasks.TaskCancellationService;
+import org.opensearch.tasks.TaskResourceTrackingService;
 import org.opensearch.tasks.TaskResultsService;
+import org.opensearch.tasks.consumer.TopNSearchTasksLogger;
+import org.opensearch.telemetry.TelemetryModule;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.metrics.MetricsRegistry;
+import org.opensearch.telemetry.metrics.MetricsRegistryFactory;
+import org.opensearch.telemetry.metrics.NoopMetricsRegistryFactory;
+import org.opensearch.telemetry.tracing.NoopTracerFactory;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.TracerFactory;
 import org.opensearch.threadpool.ExecutorBuilder;
+import org.opensearch.threadpool.RunnableTaskExecutionListener;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterService;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportService;
 import org.opensearch.usage.UsageService;
+import org.opensearch.watcher.ResourceWatcherService;
 
 import javax.net.ssl.SNIHostName;
+
 import java.io.BufferedWriter;
 import java.io.Closeable;
 import java.io.IOException;
@@ -205,6 +256,8 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -213,17 +266,24 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 import java.util.function.UnaryOperator;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static java.util.stream.Collectors.toList;
+import static org.opensearch.common.util.FeatureFlags.TELEMETRY;
+import static org.opensearch.env.NodeEnvironment.collectFileCacheDataPath;
 import static org.opensearch.index.ShardIndexingPressureSettings.SHARD_INDEXING_PRESSURE_ENABLED_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreAttributePresent;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreClusterStateEnabled;
 
 /**
  * A node represent a node within a cluster ({@code cluster.name}). The {@link #client()} can be used
  * in order to use a {@link Client} to perform actions/operations against the cluster.
+ *
+ * @opensearch.internal
  */
 public class Node implements Closeable {
     public static final Setting<Boolean> WRITE_PORTS_FILE_SETTING = Setting.boolSetting("node.portsfile", false, Property.NodeScope);
@@ -293,8 +353,19 @@ public class Node implements Closeable {
         }
     }, Setting.Property.NodeScope);
 
+    public static final Setting<ByteSizeValue> NODE_SEARCH_CACHE_SIZE_SETTING = Setting.byteSizeSetting(
+        "node.search.cache.size",
+        ByteSizeValue.ZERO,
+        Property.NodeScope
+    );
+
     private static final String CLIENT_TYPE = "node";
 
+    /**
+     * The discovery settings for the node.
+     *
+     * @opensearch.internal
+     */
     public static class DiscoverySettings {
         public static final Setting<TimeValue> INITIAL_STATE_TIMEOUT_SETTING = Setting.positiveTimeSetting(
             "discovery.initial_state_timeout",
@@ -319,11 +390,18 @@ public static class DiscoverySettings {
     private final Environment environment;
     private final NodeEnvironment nodeEnvironment;
     private final PluginsService pluginsService;
+    private final ExtensionsManager extensionsManager;
     private final NodeClient client;
     private final Collection<LifecycleComponent> pluginLifecycleComponents;
     private final LocalNodeFactory localNodeFactory;
     private final NodeService nodeService;
+    private final Tracer tracer;
+
+    private final MetricsRegistry metricsRegistry;
     final NamedWriteableRegistry namedWriteableRegistry;
+    private final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener;
+    private FileCache fileCache;
+    private final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
 
     public Node(Environment environment) {
         this(environment, Collections.emptyList(), true);
@@ -348,11 +426,7 @@ protected Node(
             Settings tmpSettings = Settings.builder()
                 .put(initialEnvironment.settings())
                 .put(Client.CLIENT_TYPE_SETTING_S.getKey(), CLIENT_TYPE)
-                .build();
-
-            // Enabling shard indexing backpressure node-attribute
-            tmpSettings = Settings.builder()
-                .put(tmpSettings)
+                // Enabling shard indexing backpressure node-attribute
                 .put(NODE_ATTRIBUTES.getKey() + SHARD_INDEXING_PRESSURE_ENABLED_ATTRIBUTE_KEY, "true")
                 .build();
 
@@ -373,7 +447,7 @@ protected Node(
                 Constants.JVM_VERSION
             );
             if (jvmInfo.getBundledJdk()) {
-                logger.info("JVM home [{}], using bundled JDK [{}]", System.getProperty("java.home"), jvmInfo.getUsingBundledJdk());
+                logger.info("JVM home [{}], using bundled JDK/JRE [{}]", System.getProperty("java.home"), jvmInfo.getUsingBundledJdk());
             } else {
                 logger.info("JVM home [{}]", System.getProperty("java.home"));
                 deprecationLogger.deprecate(
@@ -406,8 +480,33 @@ protected Node(
                 initialEnvironment.pluginsFile(),
                 classpathPlugins
             );
+
             final Settings settings = pluginsService.updatedSettings();
 
+            // Ensure to initialize Feature Flags via the settings from opensearch.yml
+            FeatureFlags.initializeFeatureFlags(settings);
+            SearchBootstrapSettings.initialize(settings);
+
+            final List<IdentityPlugin> identityPlugins = new ArrayList<>();
+            if (FeatureFlags.isEnabled(FeatureFlags.IDENTITY)) {
+                // If identity is enabled load plugins implementing the extension point
+                logger.info("Identity on so found plugins implementing: " + pluginsService.filterPlugins(IdentityPlugin.class).toString());
+                identityPlugins.addAll(pluginsService.filterPlugins(IdentityPlugin.class));
+            }
+
+            final IdentityService identityService = new IdentityService(settings, identityPlugins);
+
+            if (FeatureFlags.isEnabled(FeatureFlags.EXTENSIONS)) {
+                final List<ExtensionAwarePlugin> extensionAwarePlugins = pluginsService.filterPlugins(ExtensionAwarePlugin.class);
+                Set<Setting<?>> additionalSettings = new HashSet<>();
+                for (ExtensionAwarePlugin extAwarePlugin : extensionAwarePlugins) {
+                    additionalSettings.addAll(extAwarePlugin.getExtensionSettings());
+                }
+                this.extensionsManager = new ExtensionsManager(additionalSettings);
+            } else {
+                this.extensionsManager = new NoopExtensionsManager();
+            }
+
             final Set<DiscoveryNodeRole> additionalRoles = pluginsService.filterPlugins(Plugin.class)
                 .stream()
                 .map(Plugin::getRoles)
@@ -415,6 +514,8 @@ protected Node(
                 .collect(Collectors.toSet());
             DiscoveryNode.setAdditionalRoles(additionalRoles);
 
+            DiscoveryNode.setDeprecatedMasterRole();
+
             /*
              * Create the environment based on the finalized view of the settings. This is to ensure that components get the same setting
              * values, no matter they ask for them from.
@@ -433,11 +534,15 @@ protected Node(
                     .collect(Collectors.toCollection(LinkedHashSet::new))
             );
             resourcesToClose.add(nodeEnvironment);
-            localNodeFactory = new LocalNodeFactory(settings, nodeEnvironment.nodeId());
 
             final List<ExecutorBuilder<?>> executorBuilders = pluginsService.getExecutorBuilders(settings);
 
-            final ThreadPool threadPool = new ThreadPool(settings, executorBuilders.toArray(new ExecutorBuilder[0]));
+            runnableTaskListener = new AtomicReference<>();
+            final ThreadPool threadPool = new ThreadPool(settings, runnableTaskListener, executorBuilders.toArray(new ExecutorBuilder[0]));
+
+            final SetOnce<RepositoriesService> repositoriesServiceReference = new SetOnce<>();
+            final RemoteStoreNodeService remoteStoreNodeService = new RemoteStoreNodeService(repositoriesServiceReference::get, threadPool);
+            localNodeFactory = new LocalNodeFactory(settings, nodeEnvironment.nodeId(), remoteStoreNodeService);
             resourcesToClose.add(() -> ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS));
             final ResourceWatcherService resourceWatcherService = new ResourceWatcherService(settings, threadPool);
             resourcesToClose.add(resourceWatcherService);
@@ -491,6 +596,24 @@ protected Node(
                     new ConsistentSettingsService(settings, clusterService, consistentSettings).newHashPublisher()
                 );
             }
+
+            TracerFactory tracerFactory;
+            MetricsRegistryFactory metricsRegistryFactory;
+            if (FeatureFlags.isEnabled(TELEMETRY)) {
+                final TelemetrySettings telemetrySettings = new TelemetrySettings(settings, clusterService.getClusterSettings());
+                List<TelemetryPlugin> telemetryPlugins = pluginsService.filterPlugins(TelemetryPlugin.class);
+                TelemetryModule telemetryModule = new TelemetryModule(telemetryPlugins, telemetrySettings);
+                tracerFactory = new TracerFactory(telemetrySettings, telemetryModule.getTelemetry(), threadPool.getThreadContext());
+                metricsRegistryFactory = new MetricsRegistryFactory(telemetrySettings, telemetryModule.getTelemetry());
+            } else {
+                tracerFactory = new NoopTracerFactory();
+                metricsRegistryFactory = new NoopMetricsRegistryFactory();
+            }
+
+            tracer = tracerFactory.getTracer();
+            metricsRegistry = metricsRegistryFactory.getMetricsRegistry();
+            resourcesToClose.add(tracer::close);
+            resourcesToClose.add(metricsRegistry::close);
             final IngestService ingestService = new IngestService(
                 clusterService,
                 threadPool,
@@ -500,7 +623,7 @@ protected Node(
                 pluginsService.filterPlugins(IngestPlugin.class),
                 client
             );
-            final SetOnce<RepositoriesService> repositoriesServiceReference = new SetOnce<>();
+
             final ClusterInfoService clusterInfoService = newClusterInfoService(settings, clusterService, threadPool, client);
             final UsageService usageService = new UsageService();
 
@@ -509,7 +632,6 @@ protected Node(
             for (Module pluginModule : pluginsService.createGuiceModules()) {
                 modules.add(pluginModule);
             }
-            final MonitorService monitorService = new MonitorService(settings, nodeEnvironment, threadPool);
             final FsHealthService fsHealthService = new FsHealthService(
                 settings,
                 clusterService.getClusterSettings(),
@@ -545,6 +667,11 @@ protected Node(
                 pluginCircuitBreakers,
                 settingsModule.getClusterSettings()
             );
+            // File cache will be initialized by the node once circuit breakers are in place.
+            initializeFileCache(settings, circuitBreakerService.getBreaker(CircuitBreaker.REQUEST));
+            final FileCacheCleaner fileCacheCleaner = new FileCacheCleaner(nodeEnvironment, fileCache);
+            final MonitorService monitorService = new MonitorService(settings, nodeEnvironment, threadPool, fileCache);
+
             pluginsService.filterPlugins(CircuitBreakerPlugin.class).forEach(plugin -> {
                 CircuitBreaker breaker = circuitBreakerService.getBreaker(plugin.getCircuitBreaker(settings).getName());
                 plugin.setCircuitBreaker(breaker);
@@ -580,6 +707,19 @@ protected Node(
                 clusterService.getClusterSettings(),
                 threadPool::relativeTimeInMillis
             );
+            final RemoteClusterStateService remoteClusterStateService;
+            if (isRemoteStoreClusterStateEnabled(settings)) {
+                remoteClusterStateService = new RemoteClusterStateService(
+                    nodeEnvironment.nodeId(),
+                    repositoriesServiceReference::get,
+                    settings,
+                    clusterService.getClusterSettings(),
+                    threadPool::preciseRelativeTimeInNanos,
+                    threadPool
+                );
+            } else {
+                remoteClusterStateService = null;
+            }
 
             // collect engine factory providers from plugins
             final Collection<EnginePlugin> enginePlugins = pluginsService.filterPlugins(EnginePlugin.class);
@@ -587,11 +727,26 @@ protected Node(
                 .map(plugin -> (Function<IndexSettings, Optional<EngineFactory>>) plugin::getEngineFactory)
                 .collect(Collectors.toList());
 
-            final Map<String, IndexStorePlugin.DirectoryFactory> indexStoreFactories = pluginsService.filterPlugins(IndexStorePlugin.class)
+            final Map<String, IndexStorePlugin.DirectoryFactory> builtInDirectoryFactories = IndexModule.createBuiltInDirectoryFactories(
+                repositoriesServiceReference::get,
+                threadPool,
+                fileCache
+            );
+
+            final Map<String, IndexStorePlugin.DirectoryFactory> directoryFactories = new HashMap<>();
+            pluginsService.filterPlugins(IndexStorePlugin.class)
                 .stream()
                 .map(IndexStorePlugin::getDirectoryFactories)
                 .flatMap(m -> m.entrySet().stream())
-                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))
+                .forEach((k, v) -> {
+                    // do not allow any plugin-provided index store type to conflict with a built-in type
+                    if (builtInDirectoryFactories.containsKey(k)) {
+                        throw new IllegalStateException("registered index store type [" + k + "] conflicts with a built-in type");
+                    }
+                    directoryFactories.put(k, v);
+                });
+            directoryFactories.putAll(builtInDirectoryFactories);
 
             final Map<String, IndexStorePlugin.RecoveryStateFactory> recoveryStateFactories = pluginsService.filterPlugins(
                 IndexStorePlugin.class
@@ -614,6 +769,17 @@ protected Node(
             rerouteServiceReference.set(rerouteService);
             clusterService.setRerouteService(rerouteService);
 
+            final RecoverySettings recoverySettings = new RecoverySettings(settings, settingsModule.getClusterSettings());
+
+            final IndexStorePlugin.DirectoryFactory remoteDirectoryFactory = new RemoteSegmentStoreDirectoryFactory(
+                repositoriesServiceReference::get,
+                threadPool,
+                recoverySettings
+            );
+
+            final SearchRequestStats searchRequestStats = new SearchRequestStats();
+
+            remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, settings);
             final IndicesService indicesService = new IndicesService(
                 settings,
                 pluginsService,
@@ -632,14 +798,23 @@ protected Node(
                 client,
                 metaStateService,
                 engineFactoryProviders,
-                indexStoreFactories,
+                Map.copyOf(directoryFactories),
                 searchModule.getValuesSourceRegistry(),
-                recoveryStateFactories
+                recoveryStateFactories,
+                remoteDirectoryFactory,
+                repositoriesServiceReference::get,
+                fileCacheCleaner,
+                searchRequestStats,
+                remoteStoreStatsTrackerFactory
             );
 
             final AliasValidator aliasValidator = new AliasValidator();
 
-            final ShardLimitValidator shardLimitValidator = new ShardLimitValidator(settings, clusterService);
+            final ShardLimitValidator shardLimitValidator = new ShardLimitValidator(settings, clusterService, systemIndices);
+            final AwarenessReplicaBalance awarenessReplicaBalance = new AwarenessReplicaBalance(
+                settings,
+                clusterService.getClusterSettings()
+            );
             final MetadataCreateIndexService metadataCreateIndexService = new MetadataCreateIndexService(
                 settings,
                 clusterService,
@@ -652,7 +827,8 @@ protected Node(
                 threadPool,
                 xContentRegistry,
                 systemIndices,
-                forbidPrivateIndexSettings
+                forbidPrivateIndexSettings,
+                awarenessReplicaBalance
             );
             pluginsService.filterPlugins(Plugin.class)
                 .forEach(
@@ -695,11 +871,14 @@ protected Node(
                 client,
                 circuitBreakerService,
                 usageService,
-                systemIndices
+                systemIndices,
+                identityService,
+                extensionsManager
             );
             modules.add(actionModule);
 
             final RestController restController = actionModule.getRestController();
+
             final NetworkModule networkModule = new NetworkModule(
                 settings,
                 pluginsService.filterPlugins(NetworkPlugin.class),
@@ -711,7 +890,8 @@ protected Node(
                 xContentRegistry,
                 networkService,
                 restController,
-                clusterService.getClusterSettings()
+                clusterService.getClusterSettings(),
+                tracer
             );
             Collection<UnaryOperator<Map<String, IndexTemplateMetadata>>> indexTemplateMetadataUpgraders = pluginsService.filterPlugins(
                 Plugin.class
@@ -725,7 +905,7 @@ protected Node(
                 systemIndices,
                 scriptService
             );
-            if (DiscoveryNode.isMasterNode(settings)) {
+            if (DiscoveryNode.isClusterManagerNode(settings)) {
                 clusterService.addListener(new SystemIndexMetadataUpgradeService(systemIndices, clusterService));
             }
             new TemplateUpgradeService(client, clusterService, threadPool, indexTemplateMetadataUpgraders);
@@ -741,8 +921,20 @@ protected Node(
                 networkModule.getTransportInterceptor(),
                 localNodeFactory,
                 settingsModule.getClusterSettings(),
-                taskHeaders
+                taskHeaders,
+                tracer
             );
+            TopNSearchTasksLogger taskConsumer = new TopNSearchTasksLogger(settings, settingsModule.getClusterSettings());
+            transportService.getTaskManager().registerTaskResourceConsumer(taskConsumer);
+            this.extensionsManager.initializeServicesAndRestHandler(
+                actionModule,
+                settingsModule,
+                transportService,
+                clusterService,
+                environment.settings(),
+                client
+            );
+            final PersistedStateRegistry persistedStateRegistry = new PersistedStateRegistry();
             final GatewayMetaState gatewayMetaState = new GatewayMetaState();
             final ResponseCollectorService responseCollectorService = new ResponseCollectorService(clusterService);
             final SearchTransportService searchTransportService = new SearchTransportService(
@@ -755,7 +947,24 @@ protected Node(
             // development. Then we can deprecate Getter and Setter for IndexingPressureService in ClusterService (#478).
             clusterService.setIndexingPressureService(indexingPressureService);
 
-            final RecoverySettings recoverySettings = new RecoverySettings(settings, settingsModule.getClusterSettings());
+            final TaskResourceTrackingService taskResourceTrackingService = new TaskResourceTrackingService(
+                settings,
+                clusterService.getClusterSettings(),
+                threadPool
+            );
+
+            final SearchBackpressureSettings searchBackpressureSettings = new SearchBackpressureSettings(
+                settings,
+                clusterService.getClusterSettings()
+            );
+
+            final SearchBackpressureService searchBackpressureService = new SearchBackpressureService(
+                searchBackpressureSettings,
+                taskResourceTrackingService,
+                threadPool,
+                transportService.getTaskManager()
+            );
+
             RepositoriesModule repositoriesModule = new RepositoriesModule(
                 this.environment,
                 pluginsService.filterPlugins(RepositoryPlugin.class),
@@ -765,6 +974,11 @@ protected Node(
                 xContentRegistry,
                 recoverySettings
             );
+            CryptoHandlerRegistry.initRegistry(
+                pluginsService.filterPlugins(CryptoPlugin.class),
+                pluginsService.filterPlugins(CryptoKeyProviderPlugin.class),
+                settings
+            );
             RepositoriesService repositoryService = repositoriesModule.getRepositoryService();
             repositoriesServiceReference.set(repositoryService);
             SnapshotsService snapshotsService = new SnapshotsService(
@@ -795,8 +1009,18 @@ protected Node(
                 clusterModule.getAllocationService(),
                 metadataCreateIndexService,
                 metadataIndexUpgradeService,
-                clusterService.getClusterSettings(),
-                shardLimitValidator
+                shardLimitValidator,
+                indicesService,
+                clusterInfoService::getClusterInfo
+            );
+
+            RemoteStoreRestoreService remoteStoreRestoreService = new RemoteStoreRestoreService(
+                clusterService,
+                clusterModule.getAllocationService(),
+                metadataCreateIndexService,
+                metadataIndexUpgradeService,
+                shardLimitValidator,
+                remoteClusterStateService
             );
 
             final DiskThresholdMonitor diskThresholdMonitor = new DiskThresholdMonitor(
@@ -815,7 +1039,7 @@ protected Node(
                 transportService,
                 namedWriteableRegistry,
                 networkService,
-                clusterService.getMasterService(),
+                clusterService.getClusterManagerService(),
                 clusterService.getClusterApplierService(),
                 clusterService.getClusterSettings(),
                 pluginsService.filterPlugins(DiscoveryPlugin.class),
@@ -823,7 +1047,29 @@ protected Node(
                 environment.configFile(),
                 gatewayMetaState,
                 rerouteService,
-                fsHealthService
+                fsHealthService,
+                persistedStateRegistry,
+                remoteStoreNodeService
+            );
+            final SearchPipelineService searchPipelineService = new SearchPipelineService(
+                clusterService,
+                threadPool,
+                this.environment,
+                scriptService,
+                analysisModule.getAnalysisRegistry(),
+                xContentRegistry,
+                namedWriteableRegistry,
+                pluginsService.filterPlugins(SearchPipelinePlugin.class),
+                client
+            );
+            final TaskCancellationMonitoringSettings taskCancellationMonitoringSettings = new TaskCancellationMonitoringSettings(
+                settings,
+                clusterService.getClusterSettings()
+            );
+            final TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+                threadPool,
+                transportService.getTaskManager(),
+                taskCancellationMonitoringSettings
             );
             this.nodeService = new NodeService(
                 settings,
@@ -842,7 +1088,11 @@ protected Node(
                 responseCollectorService,
                 searchTransportService,
                 indexingPressureService,
-                searchModule.getValuesSourceRegistry().getUsageService()
+                searchModule.getValuesSourceRegistry().getUsageService(),
+                searchBackpressureService,
+                searchPipelineService,
+                fileCache,
+                taskCancellationMonitoringService
             );
 
             final SearchService searchService = newSearchService(
@@ -890,6 +1140,7 @@ protected Node(
                 b.bind(Client.class).toInstance(client);
                 b.bind(NodeClient.class).toInstance(client);
                 b.bind(Environment.class).toInstance(this.environment);
+                b.bind(ExtensionsManager.class).toInstance(this.extensionsManager);
                 b.bind(ThreadPool.class).toInstance(threadPool);
                 b.bind(NodeEnvironment.class).toInstance(nodeEnvironment);
                 b.bind(ResourceWatcherService.class).toInstance(resourceWatcherService);
@@ -899,7 +1150,10 @@ protected Node(
                 b.bind(ScriptService.class).toInstance(scriptService);
                 b.bind(AnalysisRegistry.class).toInstance(analysisModule.getAnalysisRegistry());
                 b.bind(IngestService.class).toInstance(ingestService);
+                b.bind(SearchPipelineService.class).toInstance(searchPipelineService);
                 b.bind(IndexingPressureService.class).toInstance(indexingPressureService);
+                b.bind(TaskResourceTrackingService.class).toInstance(taskResourceTrackingService);
+                b.bind(SearchBackpressureService.class).toInstance(searchBackpressureService);
                 b.bind(UsageService.class).toInstance(usageService);
                 b.bind(AggregationUsageService.class).toInstance(searchModule.getValuesSourceRegistry().getUsageService());
                 b.bind(NamedWriteableRegistry.class).toInstance(namedWriteableRegistry);
@@ -907,8 +1161,10 @@ protected Node(
                 b.bind(MetaStateService.class).toInstance(metaStateService);
                 b.bind(PersistedClusterStateService.class).toInstance(lucenePersistedStateFactory);
                 b.bind(IndicesService.class).toInstance(indicesService);
+                b.bind(RemoteStoreStatsTrackerFactory.class).toInstance(remoteStoreStatsTrackerFactory);
                 b.bind(AliasValidator.class).toInstance(aliasValidator);
                 b.bind(MetadataCreateIndexService.class).toInstance(metadataCreateIndexService);
+                b.bind(AwarenessReplicaBalance.class).toInstance(awarenessReplicaBalance);
                 b.bind(MetadataCreateDataStreamService.class).toInstance(metadataCreateDataStreamService);
                 b.bind(SearchService.class).toInstance(searchService);
                 b.bind(SearchTransportService.class).toInstance(searchTransportService);
@@ -929,6 +1185,19 @@ protected Node(
                         .toInstance(new PeerRecoverySourceService(transportService, indicesService, recoverySettings));
                     b.bind(PeerRecoveryTargetService.class)
                         .toInstance(new PeerRecoveryTargetService(threadPool, transportService, recoverySettings, clusterService));
+                    b.bind(SegmentReplicationTargetService.class)
+                        .toInstance(
+                            new SegmentReplicationTargetService(
+                                threadPool,
+                                recoverySettings,
+                                transportService,
+                                new SegmentReplicationSourceFactory(transportService, recoverySettings, clusterService),
+                                indicesService,
+                                clusterService
+                            )
+                        );
+                    b.bind(SegmentReplicationSourceService.class)
+                        .toInstance(new SegmentReplicationSourceService(indicesService, transportService, recoverySettings));
                 }
                 b.bind(HttpServerTransport.class).toInstance(httpServerTransport);
                 pluginComponents.stream().forEach(p -> b.bind((Class) p.getClass()).toInstance(p));
@@ -940,10 +1209,17 @@ protected Node(
                 b.bind(SnapshotShardsService.class).toInstance(snapshotShardsService);
                 b.bind(TransportNodesSnapshotsStatus.class).toInstance(nodesSnapshotsStatus);
                 b.bind(RestoreService.class).toInstance(restoreService);
+                b.bind(RemoteStoreRestoreService.class).toInstance(remoteStoreRestoreService);
                 b.bind(RerouteService.class).toInstance(rerouteService);
                 b.bind(ShardLimitValidator.class).toInstance(shardLimitValidator);
                 b.bind(FsHealthService.class).toInstance(fsHealthService);
                 b.bind(SystemIndices.class).toInstance(systemIndices);
+                b.bind(IdentityService.class).toInstance(identityService);
+                b.bind(Tracer.class).toInstance(tracer);
+                b.bind(SearchRequestStats.class).toInstance(searchRequestStats);
+                b.bind(MetricsRegistry.class).toInstance(metricsRegistry);
+                b.bind(RemoteClusterStateService.class).toProvider(() -> remoteClusterStateService);
+                b.bind(PersistedStateRegistry.class).toInstance(persistedStateRegistry);
             });
             injector = modules.createInjector();
 
@@ -964,8 +1240,15 @@ protected Node(
             resourcesToClose.addAll(pluginLifecycleComponents);
             resourcesToClose.add(injector.getInstance(PeerRecoverySourceService.class));
             this.pluginLifecycleComponents = Collections.unmodifiableList(pluginLifecycleComponents);
-            client.initialize(injector.getInstance(new Key<Map<ActionType, TransportAction>>() {
-            }), () -> clusterService.localNode().getId(), transportService.getRemoteClusterService(), namedWriteableRegistry);
+            DynamicActionRegistry dynamicActionRegistry = actionModule.getDynamicActionRegistry();
+            dynamicActionRegistry.registerUnmodifiableActionMap(injector.getInstance(new Key<Map<ActionType, TransportAction>>() {
+            }));
+            client.initialize(
+                dynamicActionRegistry,
+                () -> clusterService.localNode().getId(),
+                transportService.getRemoteClusterService(),
+                namedWriteableRegistry
+            );
             this.namedWriteableRegistry = namedWriteableRegistry;
 
             logger.debug("initializing HTTP handlers ...");
@@ -989,9 +1272,10 @@ protected TransportService newTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
-        return new TransportService(settings, transport, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders);
+        return new TransportService(settings, transport, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders, tracer);
     }
 
     protected void processRecoverySettings(ClusterSettings clusterSettings, RecoverySettings recoverySettings) {
@@ -1046,6 +1330,8 @@ public Node start() throws NodeValidationException {
         injector.getInstance(SearchService.class).start();
         injector.getInstance(FsHealthService.class).start();
         nodeService.getMonitorService().start();
+        nodeService.getSearchBackpressureService().start();
+        nodeService.getTaskCancellationMonitoringService().start();
 
         final ClusterService clusterService = injector.getInstance(ClusterService.class);
 
@@ -1055,18 +1341,28 @@ public Node start() throws NodeValidationException {
 
         injector.getInstance(GatewayService.class).start();
         Discovery discovery = injector.getInstance(Discovery.class);
-        clusterService.getMasterService().setClusterStatePublisher(discovery::publish);
+        clusterService.getClusterManagerService().setClusterStatePublisher(discovery::publish);
 
         // Start the transport service now so the publish address will be added to the local disco node in ClusterService
         TransportService transportService = injector.getInstance(TransportService.class);
         transportService.getTaskManager().setTaskResultsService(injector.getInstance(TaskResultsService.class));
         transportService.getTaskManager().setTaskCancellationService(new TaskCancellationService(transportService));
+
+        TaskResourceTrackingService taskResourceTrackingService = injector.getInstance(TaskResourceTrackingService.class);
+        transportService.getTaskManager().setTaskResourceTrackingService(taskResourceTrackingService);
+        runnableTaskListener.set(taskResourceTrackingService);
+
         transportService.start();
         assert localNodeFactory.getNode() != null;
         assert transportService.getLocalNode().equals(localNodeFactory.getNode())
             : "transportService has a different local node than the factory provided";
         injector.getInstance(PeerRecoverySourceService.class).start();
+        injector.getInstance(SegmentReplicationSourceService.class).start();
 
+        final RemoteClusterStateService remoteClusterStateService = injector.getInstance(RemoteClusterStateService.class);
+        if (remoteClusterStateService != null) {
+            remoteClusterStateService.start();
+        }
         // Load (and maybe upgrade) the metadata stored on disk
         final GatewayMetaState gatewayMetaState = injector.getInstance(GatewayMetaState.class);
         gatewayMetaState.start(
@@ -1076,7 +1372,10 @@ public Node start() throws NodeValidationException {
             injector.getInstance(MetaStateService.class),
             injector.getInstance(MetadataIndexUpgradeService.class),
             injector.getInstance(MetadataUpgrader.class),
-            injector.getInstance(PersistedClusterStateService.class)
+            injector.getInstance(PersistedClusterStateService.class),
+            injector.getInstance(RemoteClusterStateService.class),
+            injector.getInstance(PersistedStateRegistry.class),
+            injector.getInstance(RemoteStoreRestoreService.class)
         );
         if (Assertions.ENABLED) {
             try {
@@ -1119,7 +1418,7 @@ public Node start() throws NodeValidationException {
             ClusterState clusterState = clusterService.state();
             ClusterStateObserver observer = new ClusterStateObserver(clusterState, clusterService, null, logger, thread.getThreadContext());
 
-            if (clusterState.nodes().getMasterNodeId() == null) {
+            if (clusterState.nodes().getClusterManagerNodeId() == null) {
                 logger.debug("waiting to join the cluster. timeout [{}]", initialStateTimeout);
                 final CountDownLatch latch = new CountDownLatch(1);
                 observer.waitForNextChange(new ClusterStateObserver.Listener() {
@@ -1138,7 +1437,7 @@ public void onTimeout(TimeValue timeout) {
                         logger.warn("timed out while waiting for initial discovery state - timeout: {}", initialStateTimeout);
                         latch.countDown();
                     }
-                }, state -> state.nodes().getMasterNodeId() != null, initialStateTimeout);
+                }, state -> state.nodes().getClusterManagerNodeId() != null, initialStateTimeout);
 
                 try {
                     latch.await();
@@ -1159,7 +1458,7 @@ public void onTimeout(TimeValue timeout) {
 
         logger.info("started");
 
-        pluginsService.filterPlugins(ClusterPlugin.class).forEach(ClusterPlugin::onNodeStarted);
+        pluginsService.filterPlugins(ClusterPlugin.class).forEach(plugin -> plugin.onNodeStarted(clusterService.localNode()));
 
         return this;
     }
@@ -1186,16 +1485,18 @@ private Node stop() {
         // stop any changes happening as a result of cluster state changes
         injector.getInstance(IndicesClusterStateService.class).stop();
         // close discovery early to not react to pings anymore.
-        // This can confuse other nodes and delay things - mostly if we're the master and we're running tests.
+        // This can confuse other nodes and delay things - mostly if we're the cluster manager and we're running tests.
         injector.getInstance(Discovery.class).stop();
         // we close indices first, so operations won't be allowed on it
         injector.getInstance(ClusterService.class).stop();
         injector.getInstance(NodeConnectionsService.class).stop();
         injector.getInstance(FsHealthService.class).stop();
         nodeService.getMonitorService().stop();
+        nodeService.getSearchBackpressureService().stop();
         injector.getInstance(GatewayService.class).stop();
         injector.getInstance(SearchService.class).stop();
         injector.getInstance(TransportService.class).stop();
+        nodeService.getTaskCancellationMonitoringService().stop();
 
         pluginLifecycleComponents.forEach(LifecycleComponent::stop);
         // we should stop this last since it waits for resources to get released
@@ -1241,6 +1542,7 @@ public synchronized void close() throws IOException {
         // close filter/fielddata caches after indices
         toClose.add(injector.getInstance(IndicesStore.class));
         toClose.add(injector.getInstance(PeerRecoverySourceService.class));
+        toClose.add(injector.getInstance(SegmentReplicationSourceService.class));
         toClose.add(() -> stopWatch.stop().start("cluster"));
         toClose.add(injector.getInstance(ClusterService.class));
         toClose.add(() -> stopWatch.stop().start("node_connections_service"));
@@ -1249,6 +1551,7 @@ public synchronized void close() throws IOException {
         toClose.add(injector.getInstance(Discovery.class));
         toClose.add(() -> stopWatch.stop().start("monitor"));
         toClose.add(nodeService.getMonitorService());
+        toClose.add(nodeService.getSearchBackpressureService());
         toClose.add(() -> stopWatch.stop().start("fsHealth"));
         toClose.add(injector.getInstance(FsHealthService.class));
         toClose.add(() -> stopWatch.stop().start("gateway"));
@@ -1257,6 +1560,7 @@ public synchronized void close() throws IOException {
         toClose.add(injector.getInstance(SearchService.class));
         toClose.add(() -> stopWatch.stop().start("transport"));
         toClose.add(injector.getInstance(TransportService.class));
+        toClose.add(nodeService.getTaskCancellationMonitoringService());
 
         for (LifecycleComponent plugin : pluginLifecycleComponents) {
             toClose.add(() -> stopWatch.stop().start("plugin(" + plugin.getClass().getName() + ")"));
@@ -1279,6 +1583,10 @@ public synchronized void close() throws IOException {
         toClose.add(() -> stopWatch.stop().start("node_environment"));
         toClose.add(injector.getInstance(NodeEnvironment.class));
         toClose.add(stopWatch::stop);
+        if (FeatureFlags.isEnabled(TELEMETRY)) {
+            toClose.add(injector.getInstance(Tracer.class));
+            toClose.add(injector.getInstance(MetricsRegistry.class));
+        }
 
         if (logger.isTraceEnabled()) {
             toClose.add(() -> logger.trace("Close times for each service:\n{}", stopWatch.prettyPrint()));
@@ -1461,8 +1769,8 @@ protected ClusterInfoService newClusterInfoService(
         NodeClient client
     ) {
         final InternalClusterInfoService service = new InternalClusterInfoService(settings, clusterService, threadPool, client);
-        if (DiscoveryNode.isMasterNode(settings)) {
-            // listen for state changes (this node starts/stops being the elected master, or new nodes are added)
+        if (DiscoveryNode.isClusterManagerNode(settings)) {
+            // listen for state changes (this node starts/stops being the elected cluster manager, or new nodes are added)
             clusterService.addListener(service);
         }
         return service;
@@ -1477,15 +1785,28 @@ private static class LocalNodeFactory implements Function<BoundTransportAddress,
         private final SetOnce<DiscoveryNode> localNode = new SetOnce<>();
         private final String persistentNodeId;
         private final Settings settings;
+        private final RemoteStoreNodeService remoteStoreNodeService;
 
-        private LocalNodeFactory(Settings settings, String persistentNodeId) {
+        private LocalNodeFactory(Settings settings, String persistentNodeId, RemoteStoreNodeService remoteStoreNodeService) {
             this.persistentNodeId = persistentNodeId;
             this.settings = settings;
+            this.remoteStoreNodeService = remoteStoreNodeService;
         }
 
         @Override
         public DiscoveryNode apply(BoundTransportAddress boundTransportAddress) {
-            localNode.set(DiscoveryNode.createLocal(settings, boundTransportAddress.publishAddress(), persistentNodeId));
+            if (isRemoteStoreAttributePresent(settings)) {
+                localNode.set(
+                    DiscoveryNode.createRemoteNodeLocal(
+                        settings,
+                        boundTransportAddress.publishAddress(),
+                        persistentNodeId,
+                        remoteStoreNodeService
+                    )
+                );
+            } else {
+                localNode.set(DiscoveryNode.createLocal(settings, boundTransportAddress.publishAddress(), persistentNodeId));
+            }
             return localNode.get();
         }
 
@@ -1494,4 +1815,49 @@ DiscoveryNode getNode() {
             return localNode.get();
         }
     }
+
+    /**
+     * Initializes the search cache with a defined capacity.
+     * The capacity of the cache is based on user configuration for {@link Node#NODE_SEARCH_CACHE_SIZE_SETTING}.
+     * If the user doesn't configure the cache size, it fails if the node is a data + search node.
+     * Else it configures the size to 80% of available capacity for a dedicated search node, if not explicitly defined.
+     */
+    private void initializeFileCache(Settings settings, CircuitBreaker circuitBreaker) throws IOException {
+        if (DiscoveryNode.isSearchNode(settings)) {
+            NodeEnvironment.NodePath fileCacheNodePath = nodeEnvironment.fileCacheNodePath();
+            long capacity = NODE_SEARCH_CACHE_SIZE_SETTING.get(settings).getBytes();
+            FsInfo.Path info = ExceptionsHelper.catchAsRuntimeException(() -> FsProbe.getFSInfo(fileCacheNodePath));
+            long availableCapacity = info.getAvailable().getBytes();
+
+            // Initialize default values for cache if NODE_SEARCH_CACHE_SIZE_SETTING is not set.
+            if (capacity == 0) {
+                // If node is not a dedicated search node without configuration, prevent cache initialization
+                if (DiscoveryNode.getRolesFromSettings(settings).stream().anyMatch(role -> !DiscoveryNodeRole.SEARCH_ROLE.equals(role))) {
+                    throw new SettingsException(
+                        "Unable to initialize the "
+                            + DiscoveryNodeRole.SEARCH_ROLE.roleName()
+                            + "-"
+                            + DiscoveryNodeRole.DATA_ROLE.roleName()
+                            + " node: Missing value for configuration "
+                            + NODE_SEARCH_CACHE_SIZE_SETTING.getKey()
+                    );
+                } else {
+                    capacity = 80 * availableCapacity / 100;
+                }
+            }
+            capacity = Math.min(capacity, availableCapacity);
+            fileCacheNodePath.fileCacheReservedSize = new ByteSizeValue(capacity, ByteSizeUnit.BYTES);
+            this.fileCache = FileCacheFactory.createConcurrentLRUFileCache(capacity, circuitBreaker);
+            List<Path> fileCacheDataPaths = collectFileCacheDataPath(fileCacheNodePath);
+            this.fileCache.restoreFromDirectory(fileCacheDataPaths);
+        }
+    }
+
+    /**
+     * Returns the {@link FileCache} instance for remote search node
+     * Note: Visible for testing
+     */
+    public FileCache fileCache() {
+        return this.fileCache;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/node/NodeClosedException.java b/server/src/main/java/org/opensearch/node/NodeClosedException.java
index f2b15cf301525..d9e8dbe8466e4 100644
--- a/server/src/main/java/org/opensearch/node/NodeClosedException.java
+++ b/server/src/main/java/org/opensearch/node/NodeClosedException.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * An exception indicating that node is closed.
  *
- *
+ * @opensearch.internal
  */
 public class NodeClosedException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/node/NodeRoleSettings.java b/server/src/main/java/org/opensearch/node/NodeRoleSettings.java
index d690cfa4caa69..6caf859ee6bd3 100644
--- a/server/src/main/java/org/opensearch/node/NodeRoleSettings.java
+++ b/server/src/main/java/org/opensearch/node/NodeRoleSettings.java
@@ -40,6 +40,11 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * Settings for a node role
+ *
+ * @opensearch.internal
+ */
 public class NodeRoleSettings {
 
     public static final Setting<List<DiscoveryNodeRole>> NODE_ROLES_SETTING = Setting.listSetting(
diff --git a/server/src/main/java/org/opensearch/node/NodeService.java b/server/src/main/java/org/opensearch/node/NodeService.java
index cf79b1e1ebe22..2688b894cb9a7 100644
--- a/server/src/main/java/org/opensearch/node/NodeService.java
+++ b/server/src/main/java/org/opensearch/node/NodeService.java
@@ -32,27 +32,32 @@
 
 package org.opensearch.node;
 
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.Build;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.search.SearchTransportService;
+import org.opensearch.cluster.routing.WeightedRoutingStats;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.index.IndexingPressureService;
+import org.opensearch.index.store.remote.filecache.FileCache;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.monitor.MonitorService;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.aggregations.support.AggregationUsageService;
+import org.opensearch.search.backpressure.SearchBackpressureService;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.tasks.TaskCancellationMonitoringService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -60,6 +65,11 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Services exposed to nodes
+ *
+ * @opensearch.internal
+ */
 public class NodeService implements Closeable {
     private final Settings settings;
     private final ThreadPool threadPool;
@@ -76,8 +86,12 @@ public class NodeService implements Closeable {
     private final SearchTransportService searchTransportService;
     private final IndexingPressureService indexingPressureService;
     private final AggregationUsageService aggregationUsageService;
-
+    private final SearchBackpressureService searchBackpressureService;
+    private final SearchPipelineService searchPipelineService;
+    private final ClusterService clusterService;
     private final Discovery discovery;
+    private final FileCache fileCache;
+    private final TaskCancellationMonitoringService taskCancellationMonitoringService;
 
     NodeService(
         Settings settings,
@@ -96,7 +110,11 @@ public class NodeService implements Closeable {
         ResponseCollectorService responseCollectorService,
         SearchTransportService searchTransportService,
         IndexingPressureService indexingPressureService,
-        AggregationUsageService aggregationUsageService
+        AggregationUsageService aggregationUsageService,
+        SearchBackpressureService searchBackpressureService,
+        SearchPipelineService searchPipelineService,
+        FileCache fileCache,
+        TaskCancellationMonitoringService taskCancellationMonitoringService
     ) {
         this.settings = settings;
         this.threadPool = threadPool;
@@ -114,7 +132,13 @@ public class NodeService implements Closeable {
         this.searchTransportService = searchTransportService;
         this.indexingPressureService = indexingPressureService;
         this.aggregationUsageService = aggregationUsageService;
+        this.searchBackpressureService = searchBackpressureService;
+        this.searchPipelineService = searchPipelineService;
+        this.clusterService = clusterService;
+        this.fileCache = fileCache;
+        this.taskCancellationMonitoringService = taskCancellationMonitoringService;
         clusterService.addStateApplier(ingestService);
+        clusterService.addStateApplier(searchPipelineService);
     }
 
     public NodeInfo info(
@@ -128,24 +152,47 @@ public NodeInfo info(
         boolean plugin,
         boolean ingest,
         boolean aggs,
-        boolean indices
+        boolean indices,
+        boolean searchPipeline
     ) {
-        return new NodeInfo(
-            Version.CURRENT,
-            Build.CURRENT,
-            transportService.getLocalNode(),
-            settings ? settingsFilter.filter(this.settings) : null,
-            os ? monitorService.osService().info() : null,
-            process ? monitorService.processService().info() : null,
-            jvm ? monitorService.jvmService().info() : null,
-            threadPool ? this.threadPool.info() : null,
-            transport ? transportService.info() : null,
-            http ? (httpServerTransport == null ? null : httpServerTransport.info()) : null,
-            plugin ? (pluginService == null ? null : pluginService.info()) : null,
-            ingest ? (ingestService == null ? null : ingestService.info()) : null,
-            aggs ? (aggregationUsageService == null ? null : aggregationUsageService.info()) : null,
-            indices ? indicesService.getTotalIndexingBufferBytes() : null
-        );
+        NodeInfo.Builder builder = NodeInfo.builder(Version.CURRENT, Build.CURRENT, transportService.getLocalNode());
+        if (settings) {
+            builder.setSettings(settingsFilter.filter(this.settings));
+        }
+        if (os) {
+            builder.setOs(monitorService.osService().info());
+        }
+        if (process) {
+            builder.setProcess(monitorService.processService().info());
+        }
+        if (jvm) {
+            builder.setJvm(monitorService.jvmService().info());
+        }
+        if (threadPool) {
+            builder.setThreadPool(this.threadPool.info());
+        }
+        if (transport) {
+            builder.setTransport(transportService.info());
+        }
+        if (http && httpServerTransport != null) {
+            builder.setHttp(httpServerTransport.info());
+        }
+        if (plugin && pluginService != null) {
+            builder.setPlugins(pluginService.info());
+        }
+        if (ingest && ingestService != null) {
+            builder.setIngest(ingestService.info());
+        }
+        if (aggs && aggregationUsageService != null) {
+            builder.setAggsInfo(aggregationUsageService.info());
+        }
+        if (indices) {
+            builder.setTotalIndexingBuffer(indicesService.getTotalIndexingBufferBytes());
+        }
+        if (searchPipeline && searchPipelineService != null) {
+            builder.setSearchPipelineInfo(searchPipelineService.info());
+        }
+        return builder.build();
     }
 
     public NodeStats stats(
@@ -164,7 +211,13 @@ public NodeStats stats(
         boolean adaptiveSelection,
         boolean scriptCache,
         boolean indexingPressure,
-        boolean shardIndexingPressure
+        boolean shardIndexingPressure,
+        boolean searchBackpressure,
+        boolean clusterManagerThrottling,
+        boolean weightedRoutingStats,
+        boolean fileCacheStats,
+        boolean taskCancellation,
+        boolean searchPipelineStats
     ) {
         // for indices stats we want to include previous allocated shards stats as well (it will
         // only be applied to the sensible ones to use, like refresh/merge/flush/indexing stats)
@@ -186,7 +239,13 @@ public NodeStats stats(
             adaptiveSelection ? responseCollectorService.getAdaptiveStats(searchTransportService.getPendingSearchRequests()) : null,
             scriptCache ? scriptService.cacheStats() : null,
             indexingPressure ? this.indexingPressureService.nodeStats() : null,
-            shardIndexingPressure ? this.indexingPressureService.shardStats(indices) : null
+            shardIndexingPressure ? this.indexingPressureService.shardStats(indices) : null,
+            searchBackpressure ? this.searchBackpressureService.nodeStats() : null,
+            clusterManagerThrottling ? this.clusterService.getClusterManagerService().getThrottlingStats() : null,
+            weightedRoutingStats ? WeightedRoutingStats.getInstance() : null,
+            fileCacheStats && fileCache != null ? fileCache.fileCacheStats() : null,
+            taskCancellation ? this.taskCancellationMonitoringService.stats() : null,
+            searchPipelineStats ? this.searchPipelineService.stats() : null
         );
     }
 
@@ -198,6 +257,14 @@ public MonitorService getMonitorService() {
         return monitorService;
     }
 
+    public SearchBackpressureService getSearchBackpressureService() {
+        return searchBackpressureService;
+    }
+
+    public TaskCancellationMonitoringService getTaskCancellationMonitoringService() {
+        return taskCancellationMonitoringService;
+    }
+
     @Override
     public void close() throws IOException {
         IOUtils.close(indicesService);
diff --git a/server/src/main/java/org/opensearch/node/NodeValidationException.java b/server/src/main/java/org/opensearch/node/NodeValidationException.java
index a50c52176ea02..b316288b7cf06 100644
--- a/server/src/main/java/org/opensearch/node/NodeValidationException.java
+++ b/server/src/main/java/org/opensearch/node/NodeValidationException.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.node;
 
-import org.opensearch.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.BoundTransportAddress;
 
 import java.util.List;
 
@@ -41,6 +41,8 @@
  * begins accepting network requests in
  * {@link Node#validateNodeBeforeAcceptingRequests(org.opensearch.bootstrap.BootstrapContext, BoundTransportAddress, List)}.
  * This exception is a checked exception that is declared as thrown from this method for the purpose of bubbling up to the user.
+ *
+ * @opensearch.internal
  */
 public class NodeValidationException extends Exception {
 
diff --git a/server/src/main/java/org/opensearch/node/ResponseCollectorService.java b/server/src/main/java/org/opensearch/node/ResponseCollectorService.java
index 869d84bc6e6b4..3451e50d27b5d 100644
--- a/server/src/main/java/org/opensearch/node/ResponseCollectorService.java
+++ b/server/src/main/java/org/opensearch/node/ResponseCollectorService.java
@@ -37,10 +37,10 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.ExponentiallyWeightedMovingAverage;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -53,6 +53,8 @@
  * Collects statistics about queue size, response time, and service time of
  * tasks executed on each node, making the EWMA of the values available to the
  * coordinating node.
+ *
+ * @opensearch.internal
  */
 public final class ResponseCollectorService implements ClusterStateListener {
 
diff --git a/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeAttribute.java b/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeAttribute.java
new file mode 100644
index 0000000000000..7b2a6c34d3db6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeAttribute.java
@@ -0,0 +1,192 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.node.remotestore;
+
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.node.Node;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * This is an abstraction for validating and storing information specific to remote backed storage nodes.
+ *
+ * @opensearch.internal
+ */
+public class RemoteStoreNodeAttribute {
+
+    public static final String REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX = "remote_store";
+    public static final String REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY = "remote_store.segment.repository";
+    public static final String REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY = "remote_store.translog.repository";
+    public static final String REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY = "remote_store.state.repository";
+    public static final String REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT = "remote_store.repository.%s.type";
+    public static final String REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT = "remote_store.repository.%s."
+        + CryptoMetadata.CRYPTO_METADATA_KEY;
+    public static final String REMOTE_STORE_REPOSITORY_CRYPTO_SETTINGS_PREFIX = REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT
+        + "."
+        + CryptoMetadata.SETTINGS_KEY;
+    public static final String REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX = "remote_store.repository.%s.settings.";
+    private final RepositoriesMetadata repositoriesMetadata;
+
+    /**
+     * Creates a new {@link RemoteStoreNodeAttribute}
+     */
+    public RemoteStoreNodeAttribute(DiscoveryNode node) {
+        this.repositoriesMetadata = buildRepositoriesMetadata(node);
+    }
+
+    private String validateAttributeNonNull(DiscoveryNode node, String attributeKey) {
+        String attributeValue = node.getAttributes().get(attributeKey);
+        if (attributeValue == null || attributeValue.isEmpty()) {
+            throw new IllegalStateException("joining node [" + node + "] doesn't have the node attribute [" + attributeKey + "]");
+        }
+
+        return attributeValue;
+    }
+
+    private CryptoMetadata buildCryptoMetadata(DiscoveryNode node, String repositoryName) {
+        String metadataKey = String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT, repositoryName);
+        boolean isRepoEncrypted = node.getAttributes().keySet().stream().anyMatch(key -> key.startsWith(metadataKey));
+        if (isRepoEncrypted == false) {
+            return null;
+        }
+
+        String keyProviderName = validateAttributeNonNull(node, metadataKey + "." + CryptoMetadata.KEY_PROVIDER_NAME_KEY);
+        String keyProviderType = validateAttributeNonNull(node, metadataKey + "." + CryptoMetadata.KEY_PROVIDER_TYPE_KEY);
+
+        String settingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_CRYPTO_SETTINGS_PREFIX,
+            repositoryName
+        );
+
+        Map<String, String> settingsMap = node.getAttributes()
+            .keySet()
+            .stream()
+            .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+            .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix + ".", ""), key -> node.getAttributes().get(key)));
+
+        Settings.Builder settings = Settings.builder();
+        settingsMap.forEach(settings::put);
+
+        return new CryptoMetadata(keyProviderName, keyProviderType, settings.build());
+    }
+
+    private Map<String, String> validateSettingsAttributesNonNull(DiscoveryNode node, String repositoryName) {
+        String settingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            repositoryName
+        );
+        Map<String, String> settingsMap = node.getAttributes()
+            .keySet()
+            .stream()
+            .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+            .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix, ""), key -> validateAttributeNonNull(node, key)));
+
+        if (settingsMap.isEmpty()) {
+            throw new IllegalStateException(
+                "joining node [" + node + "] doesn't have settings attribute for [" + repositoryName + "] repository"
+            );
+        }
+
+        return settingsMap;
+    }
+
+    private RepositoryMetadata buildRepositoryMetadata(DiscoveryNode node, String name) {
+        String type = validateAttributeNonNull(
+            node,
+            String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, name)
+        );
+        Map<String, String> settingsMap = validateSettingsAttributesNonNull(node, name);
+
+        Settings.Builder settings = Settings.builder();
+        settingsMap.forEach(settings::put);
+
+        CryptoMetadata cryptoMetadata = buildCryptoMetadata(node, name);
+
+        // Repository metadata built here will always be for a system repository.
+        settings.put(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING.getKey(), true);
+
+        return new RepositoryMetadata(name, type, settings.build(), cryptoMetadata);
+    }
+
+    private RepositoriesMetadata buildRepositoriesMetadata(DiscoveryNode node) {
+        List<RepositoryMetadata> repositoryMetadataList = new ArrayList<>();
+        Set<String> repositoryNames = new HashSet<>();
+
+        repositoryNames.add(validateAttributeNonNull(node, REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY));
+        repositoryNames.add(validateAttributeNonNull(node, REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY));
+        repositoryNames.add(validateAttributeNonNull(node, REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY));
+
+        for (String repositoryName : repositoryNames) {
+            repositoryMetadataList.add(buildRepositoryMetadata(node, repositoryName));
+        }
+
+        return new RepositoriesMetadata(repositoryMetadataList);
+    }
+
+    public static boolean isRemoteStoreAttributePresent(Settings settings) {
+        return settings.getByPrefix(Node.NODE_ATTRIBUTES.getKey() + REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX).isEmpty() == false;
+    }
+
+    public static boolean isRemoteStoreClusterStateEnabled(Settings settings) {
+        return RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.get(settings) && isRemoteStoreAttributePresent(settings);
+    }
+
+    public RepositoriesMetadata getRepositoriesMetadata() {
+        return this.repositoriesMetadata;
+    }
+
+    @Override
+    public int hashCode() {
+        // The hashCode is generated by computing the hash of all the repositoryMetadata present in
+        // repositoriesMetadata without generation. Below is the modified list hashCode generation logic.
+
+        int hashCode = 1;
+        Iterator iterator = this.repositoriesMetadata.repositories().iterator();
+        while (iterator.hasNext()) {
+            RepositoryMetadata repositoryMetadata = (RepositoryMetadata) iterator.next();
+            hashCode = 31 * hashCode + (repositoryMetadata == null
+                ? 0
+                : Objects.hash(repositoryMetadata.name(), repositoryMetadata.type(), repositoryMetadata.settings()));
+        }
+        return hashCode;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        RemoteStoreNodeAttribute that = (RemoteStoreNodeAttribute) o;
+
+        return this.getRepositoriesMetadata().equalsIgnoreGenerations(that.getRepositoriesMetadata());
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append('{').append(this.repositoriesMetadata).append('}');
+        return super.toString();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeService.java b/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeService.java
new file mode 100644
index 0000000000000..ca2413a057a6b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeService.java
@@ -0,0 +1,169 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.node.remotestore;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.RepositoryException;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * Contains all the method needed for a remote store backed node lifecycle.
+ */
+public class RemoteStoreNodeService {
+
+    private static final Logger logger = LogManager.getLogger(RemoteStoreNodeService.class);
+    private final Supplier<RepositoriesService> repositoriesService;
+    private final ThreadPool threadPool;
+    public static final Setting<CompatibilityMode> REMOTE_STORE_COMPATIBILITY_MODE_SETTING = new Setting<>(
+        "remote_store.compatibility_mode",
+        CompatibilityMode.STRICT.name(),
+        CompatibilityMode::parseString,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Node join compatibility mode introduced with remote backed storage.
+     *
+     * @opensearch.internal
+     */
+    public enum CompatibilityMode {
+        STRICT("strict");
+
+        public final String mode;
+
+        CompatibilityMode(String mode) {
+            this.mode = mode;
+        }
+
+        public static CompatibilityMode parseString(String compatibilityMode) {
+            try {
+                return CompatibilityMode.valueOf(compatibilityMode.toUpperCase(Locale.ROOT));
+            } catch (IllegalArgumentException e) {
+                throw new IllegalArgumentException(
+                    "["
+                        + compatibilityMode
+                        + "] compatibility mode is not supported. "
+                        + "supported modes are ["
+                        + CompatibilityMode.values().toString()
+                        + "]"
+                );
+            }
+        }
+    }
+
+    public RemoteStoreNodeService(Supplier<RepositoriesService> repositoriesService, ThreadPool threadPool) {
+        this.repositoriesService = repositoriesService;
+        this.threadPool = threadPool;
+    }
+
+    /**
+     * Creates a repository during a node startup and performs verification by invoking verify method against
+     * mentioned repository. This verification will happen on a local node to validate if the node is able to connect
+     * to the repository with appropriate permissions.
+     * If the creation or verification fails this will close all the repositories this method created and throw
+     * exception.
+     */
+    public void createAndVerifyRepositories(DiscoveryNode localNode) {
+        RemoteStoreNodeAttribute nodeAttribute = new RemoteStoreNodeAttribute(localNode);
+        RepositoriesService reposService = repositoriesService.get();
+        Map<String, Repository> repositories = new HashMap<>();
+        for (RepositoryMetadata repositoryMetadata : nodeAttribute.getRepositoriesMetadata().repositories()) {
+            String repositoryName = repositoryMetadata.name();
+            Repository repository;
+            RepositoriesService.validate(repositoryName);
+
+            // Create Repository
+            repository = reposService.createRepository(repositoryMetadata);
+            logger.info(
+                "remote backed storage repository with name [{}] and type [{}] created",
+                repository.getMetadata().name(),
+                repository.getMetadata().type()
+            );
+
+            // Verify Repository
+            String verificationToken = repository.startVerification();
+            repository.verify(verificationToken, localNode);
+            repository.endVerification(verificationToken);
+            logger.info(() -> new ParameterizedMessage("successfully verified [{}] repository", repositoryName));
+            repositories.put(repositoryName, repository);
+        }
+        // Updating the repositories map in RepositoriesService
+        reposService.updateRepositoriesMap(repositories);
+    }
+
+    /**
+     * Updates repositories metadata in the cluster state if not already present. If a repository metadata for a
+     * repository is already present in the cluster state and if it's different then the joining remote store backed
+     * node repository metadata an exception will be thrown and the node will not be allowed to join the cluster.
+     */
+    public RepositoriesMetadata updateRepositoriesMetadata(DiscoveryNode joiningNode, RepositoriesMetadata existingRepositories) {
+        if (joiningNode.isRemoteStoreNode()) {
+            List<RepositoryMetadata> updatedRepositoryMetadataList = new ArrayList<>();
+            List<RepositoryMetadata> newRepositoryMetadataList = new RemoteStoreNodeAttribute(joiningNode).getRepositoriesMetadata()
+                .repositories();
+
+            if (existingRepositories == null) {
+                return new RepositoriesMetadata(newRepositoryMetadataList);
+            } else {
+                updatedRepositoryMetadataList.addAll(existingRepositories.repositories());
+            }
+
+            for (RepositoryMetadata newRepositoryMetadata : newRepositoryMetadataList) {
+                boolean repositoryAlreadyPresent = false;
+                for (RepositoryMetadata existingRepositoryMetadata : existingRepositories.repositories()) {
+                    if (newRepositoryMetadata.name().equals(existingRepositoryMetadata.name())) {
+                        try {
+                            // This will help in handling two scenarios -
+                            // 1. When a fresh cluster is formed and a node tries to join the cluster, the repository
+                            // metadata constructed from the node attributes of the joining node will be validated
+                            // against the repository information provided by existing nodes in cluster state.
+                            // 2. It's possible to update repository settings except the restricted ones post the
+                            // creation of a system repository and if a node drops we will need to allow it to join
+                            // even if the non-restricted system repository settings are now different.
+                            repositoriesService.get().ensureValidSystemRepositoryUpdate(newRepositoryMetadata, existingRepositoryMetadata);
+                            newRepositoryMetadata = existingRepositoryMetadata;
+                            repositoryAlreadyPresent = true;
+                            break;
+                        } catch (RepositoryException e) {
+                            throw new IllegalStateException(
+                                "new repository metadata ["
+                                    + newRepositoryMetadata
+                                    + "] supplied by joining node is different from existing repository metadata ["
+                                    + existingRepositoryMetadata
+                                    + "]."
+                            );
+                        }
+                    }
+                }
+                if (repositoryAlreadyPresent == false) {
+                    updatedRepositoryMetadataList.add(newRepositoryMetadata);
+                }
+            }
+            return new RepositoriesMetadata(updatedRepositoryMetadataList);
+        } else {
+            return existingRepositories;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/node/remotestore/package-info.java b/server/src/main/java/org/opensearch/node/remotestore/package-info.java
new file mode 100644
index 0000000000000..e2592aa5fcc29
--- /dev/null
+++ b/server/src/main/java/org/opensearch/node/remotestore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Restore remote store transport handler. */
+package org.opensearch.node.remotestore;
diff --git a/server/src/main/java/org/opensearch/persistent/AllocatedPersistentTask.java b/server/src/main/java/org/opensearch/persistent/AllocatedPersistentTask.java
index 48397a1b1e8df..1e20a3b1d5275 100644
--- a/server/src/main/java/org/opensearch/persistent/AllocatedPersistentTask.java
+++ b/server/src/main/java/org/opensearch/persistent/AllocatedPersistentTask.java
@@ -34,12 +34,12 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.CancellableTask;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
 
 import java.util.Map;
@@ -48,6 +48,8 @@
 
 /**
  * Represents a executor node operation that corresponds to a persistent task
+ *
+ * @opensearch.internal
  */
 public class AllocatedPersistentTask extends CancellableTask {
 
@@ -204,6 +206,11 @@ public void onFailure(Exception e) {
         }
     }
 
+    /**
+     * The state of the task.
+     *
+     * @opensearch.internal
+     */
     public enum State {
         STARTED,  // the task is currently running
         PENDING_CANCEL, // the task is cancelled on master, cancelling it locally
diff --git a/server/src/main/java/org/opensearch/persistent/CompletionPersistentTaskAction.java b/server/src/main/java/org/opensearch/persistent/CompletionPersistentTaskAction.java
index 4aa9b8d7eb781..e43a67ea82fdd 100644
--- a/server/src/main/java/org/opensearch/persistent/CompletionPersistentTaskAction.java
+++ b/server/src/main/java/org/opensearch/persistent/CompletionPersistentTaskAction.java
@@ -31,13 +31,12 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -45,8 +44,9 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -58,6 +58,8 @@
 /**
  * ActionType that is used by executor node to indicate that the persistent action finished or failed on the node and needs to be
  * removed from the cluster state in case of successful completion or restarted on some other node in case of failure.
+ *
+ * @opensearch.internal
  */
 public class CompletionPersistentTaskAction extends ActionType<PersistentTaskResponse> {
 
@@ -68,7 +70,12 @@ private CompletionPersistentTaskAction() {
         super(NAME, PersistentTaskResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * The request.
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String taskId;
 
@@ -127,17 +134,24 @@ public int hashCode() {
         }
     }
 
-    public static class RequestBuilder extends MasterNodeOperationRequestBuilder<
-        CompletionPersistentTaskAction.Request,
-        PersistentTaskResponse,
-        CompletionPersistentTaskAction.RequestBuilder> {
+    /**
+     * The request bulder.
+     *
+     * @opensearch.internal
+     */
+    public static class RequestBuilder extends ClusterManagerNodeOperationRequestBuilder<Request, PersistentTaskResponse, RequestBuilder> {
 
         protected RequestBuilder(OpenSearchClient client, CompletionPersistentTaskAction action) {
             super(client, action, new Request());
         }
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, PersistentTaskResponse> {
+    /**
+     * The transport action.
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, PersistentTaskResponse> {
 
         private final PersistentTasksClusterService persistentTasksClusterService;
 
@@ -179,7 +193,7 @@ protected ClusterBlockException checkBlock(Request request, ClusterState state)
         }
 
         @Override
-        protected final void masterOperation(
+        protected final void clusterManagerOperation(
             final Request request,
             ClusterState state,
             final ActionListener<PersistentTaskResponse> listener
diff --git a/server/src/main/java/org/opensearch/persistent/NodePersistentTasksExecutor.java b/server/src/main/java/org/opensearch/persistent/NodePersistentTasksExecutor.java
index d62a6dd669a6c..209df1e1f498d 100644
--- a/server/src/main/java/org/opensearch/persistent/NodePersistentTasksExecutor.java
+++ b/server/src/main/java/org/opensearch/persistent/NodePersistentTasksExecutor.java
@@ -39,6 +39,8 @@
  * This component is responsible for execution of persistent tasks.
  *
  * It abstracts away the execution of tasks and greatly simplifies testing of PersistentTasksNodeService
+ *
+ * @opensearch.internal
  */
 public class NodePersistentTasksExecutor {
 
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTaskParams.java b/server/src/main/java/org/opensearch/persistent/PersistentTaskParams.java
index e10d70688a912..b71d7f61d0106 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTaskParams.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTaskParams.java
@@ -33,11 +33,13 @@
 package org.opensearch.persistent;
 
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.common.io.stream.VersionedNamedWriteable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.VersionedNamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 /**
  * Parameters used to start persistent task
+ *
+ * @opensearch.internal
  */
 public interface PersistentTaskParams extends VersionedNamedWriteable, ToXContentObject, ClusterState.FeatureAware {
 
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTaskResponse.java b/server/src/main/java/org/opensearch/persistent/PersistentTaskResponse.java
index cc09d3d0b39d7..c52b5574ecf5e 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTaskResponse.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTaskResponse.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 
 import java.io.IOException;
@@ -41,6 +41,8 @@
 
 /**
  * Response upon a successful start or an persistent task
+ *
+ * @opensearch.internal
  */
 public class PersistentTaskResponse extends ActionResponse {
     private PersistentTask<?> task;
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTaskState.java b/server/src/main/java/org/opensearch/persistent/PersistentTaskState.java
index 3b57ce92e8634..954c5c3e1938c 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTaskState.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTaskState.java
@@ -31,11 +31,13 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 /**
  * {@link PersistentTaskState} represents the state of the persistent tasks, as it
  * is persisted in the cluster state.
+ *
+ * @opensearch.internal
  */
 public interface PersistentTaskState extends ToXContentObject, NamedWriteable {}
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksClusterService.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksClusterService.java
index 00a5f335338c4..89bb23930b063 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksClusterService.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksClusterService.java
@@ -36,20 +36,22 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractAsyncTask;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.persistent.decider.AssignmentDecision;
@@ -60,7 +62,9 @@
 import java.util.Objects;
 
 /**
- * Component that runs only on the master node and is responsible for assigning running tasks to nodes
+ * Component that runs only on the cluster-manager node and is responsible for assigning running tasks to nodes
+ *
+ * @opensearch.internal
  */
 public class PersistentTasksClusterService implements ClusterStateListener, Closeable {
 
@@ -79,6 +83,10 @@ public class PersistentTasksClusterService implements ClusterStateListener, Clos
     private final EnableAssignmentDecider decider;
     private final ThreadPool threadPool;
     private final PeriodicRechecker periodicRechecker;
+    private final ClusterManagerTaskThrottler.ThrottlingKey createPersistentTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey finishPersistentTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey removePersistentTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey updatePersistentTaskKey;
 
     public PersistentTasksClusterService(
         Settings settings,
@@ -91,11 +99,17 @@ public PersistentTasksClusterService(
         this.decider = new EnableAssignmentDecider(settings, clusterService.getClusterSettings());
         this.threadPool = threadPool;
         this.periodicRechecker = new PeriodicRechecker(CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING.get(settings));
-        if (DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isClusterManagerNode(settings)) {
             clusterService.addListener(this);
         }
         clusterService.getClusterSettings()
             .addSettingsUpdateConsumer(CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING, this::setRecheckInterval);
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        createPersistentTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_PERSISTENT_TASK_KEY, true);
+        finishPersistentTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.FINISH_PERSISTENT_TASK_KEY, true);
+        removePersistentTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.REMOVE_PERSISTENT_TASK_KEY, true);
+        updatePersistentTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.UPDATE_TASK_STATE_KEY, true);
     }
 
     // visible for testing only
@@ -114,7 +128,7 @@ public void close() {
     }
 
     /**
-     * Creates a new persistent task on master node
+     * Creates a new persistent task on cluster-manager node
      *
      * @param taskId     the task's id
      * @param taskName   the task's name
@@ -142,6 +156,11 @@ public ClusterState execute(ClusterState currentState) {
                 return update(currentState, builder.addTask(taskId, taskName, taskParams, assignment));
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return createPersistentTaskKey;
+            }
+
             @Override
             public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
@@ -201,6 +220,11 @@ public ClusterState execute(ClusterState currentState) {
                 }
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return finishPersistentTaskKey;
+            }
+
             @Override
             public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
@@ -232,6 +256,11 @@ public ClusterState execute(ClusterState currentState) {
                 }
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return removePersistentTaskKey;
+            }
+
             @Override
             public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
@@ -275,6 +304,11 @@ public ClusterState execute(ClusterState currentState) {
                 }
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return updatePersistentTaskKey;
+            }
+
             @Override
             public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
@@ -354,7 +388,7 @@ private <Params extends PersistentTaskParams> Assignment createAssignment(
 
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
-        if (event.localNodeMaster()) {
+        if (event.localNodeClusterManager()) {
             if (shouldReassignPersistentTasks(event)) {
                 // We want to avoid a periodic check duplicating this work
                 periodicRechecker.cancel();
@@ -379,7 +413,7 @@ public ClusterState execute(ClusterState currentState) {
             @Override
             public void onFailure(String source, Exception e) {
                 logger.warn("failed to reassign persistent tasks", e);
-                if (e instanceof NotMasterException == false) {
+                if (e instanceof NotClusterManagerException == false) {
                     // There must be a task that's worth rechecking because there was one
                     // that caused this method to be called and the method failed to assign it,
                     // but only do this if the node is still the master
@@ -398,7 +432,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
 
     /**
      * Returns true if the cluster state change(s) require to reassign some persistent tasks. It can happen in the following
-     * situations: a node left or is added, the routing table changed, the master node changed, the metadata changed or the
+     * situations: a node left or is added, the routing table changed, the cluster-manager node changed, the metadata changed or the
      * persistent tasks changed.
      */
     boolean shouldReassignPersistentTasks(final ClusterChangedEvent event) {
@@ -407,7 +441,7 @@ boolean shouldReassignPersistentTasks(final ClusterChangedEvent event) {
             return false;
         }
 
-        boolean masterChanged = event.previousState().nodes().isLocalNodeElectedMaster() == false;
+        boolean masterChanged = event.previousState().nodes().isLocalNodeElectedClusterManager() == false;
 
         if (persistentTasksChanged(event)
             || event.nodesChanged()
@@ -516,7 +550,7 @@ protected boolean mustReschedule() {
 
         @Override
         public void runInternal() {
-            if (clusterService.localNode().isMasterNode()) {
+            if (clusterService.localNode().isClusterManagerNode()) {
                 final ClusterState state = clusterService.state();
                 logger.trace("periodic persistent task assignment check running for cluster state {}", state.getVersion());
                 if (isAnyTaskUnassigned(state.getMetadata().custom(PersistentTasksCustomMetadata.TYPE))) {
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksCustomMetadata.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksCustomMetadata.java
index d39e96e9da9e3..c83362ac2d5ab 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksCustomMetadata.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksCustomMetadata.java
@@ -40,18 +40,19 @@
 import org.opensearch.cluster.NamedDiff;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -67,10 +68,12 @@
 import java.util.stream.Collectors;
 
 import static org.opensearch.cluster.metadata.Metadata.ALL_CONTEXTS;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * A cluster state record that contains a list of all running persistent tasks
+ *
+ * @opensearch.internal
  */
 public final class PersistentTasksCustomMetadata extends AbstractNamedDiffable<Metadata.Custom> implements Metadata.Custom {
 
@@ -208,7 +211,7 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     public long getNumberOfTasksOnNode(String nodeId, String taskName) {
@@ -274,6 +277,12 @@ public static ClusterState disassociateDeadNodes(ClusterState clusterState) {
         return ClusterState.builder(clusterState).metadata(metadataBuilder).build();
     }
 
+    /**
+     * The assignment.
+     *
+     * @opensearch.internal
+     */
+
     public static class Assignment {
         @Nullable
         private final String executorNode;
@@ -420,7 +429,7 @@ public int hashCode() {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
         public String getId() {
@@ -596,6 +605,11 @@ public static Builder builder(PersistentTasksCustomMetadata tasks) {
         return new Builder(tasks);
     }
 
+    /**
+     * The task builder.
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private final Map<String, PersistentTask<?>> tasks = new HashMap<>();
         private long lastAllocationId;
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutor.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutor.java
index 0c6e3bb590506..ab2e50d5fb42b 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutor.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutor.java
@@ -35,9 +35,9 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
-import org.opensearch.tasks.TaskId;
 
 import java.util.Map;
 import java.util.function.Predicate;
@@ -45,6 +45,8 @@
 /**
  * An executor of tasks that can survive restart of requesting or executing node.
  * These tasks are using cluster state rather than only transport service to send requests and responses.
+ *
+ * @opensearch.internal
  */
 public abstract class PersistentTasksExecutor<Params extends PersistentTaskParams> {
 
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutorRegistry.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutorRegistry.java
index 3f9bd06ead44b..8de183faa0464 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutorRegistry.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksExecutorRegistry.java
@@ -38,6 +38,8 @@
 
 /**
  * Components that registers all persistent task executors
+ *
+ * @opensearch.internal
  */
 public class PersistentTasksExecutorRegistry {
 
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksNodeService.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksNodeService.java
index 4a12208d675e9..602be47476ad2 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksNodeService.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksNodeService.java
@@ -34,19 +34,20 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateListener;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskAwareRequest;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
 
 import java.io.IOException;
@@ -61,6 +62,8 @@
 /**
  * This component is responsible for coordination of execution of persistent tasks on individual nodes. It runs on all
  * nodes in the cluster and monitors cluster state changes to detect started commands.
+ *
+ * @opensearch.internal
  */
 public class PersistentTasksNodeService implements ClusterStateListener {
 
@@ -87,7 +90,7 @@ public PersistentTasksNodeService(
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
         if (event.state().blocks().hasGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK)) {
-            // wait until the gateway has recovered from disk, otherwise if the only master restarts
+            // wait until the gateway has recovered from disk, otherwise if the only cluster-manager restarts
             // we start cancelling all local tasks before cluster has a chance to recover.
             return;
         }
@@ -103,18 +106,18 @@ public void clusterChanged(ClusterChangedEvent event) {
         // NULL STARTED Remove locally, Mark as PENDING_CANCEL, Cancel
         // NULL COMPLETED Remove locally
 
-        // Master states:
+        // Cluster-manager states:
         // NULL - doesn't exist in the cluster state
         // STARTED - exist in the cluster state
 
         // Local state:
         // NULL - we don't have task registered locally in runningTasks
-        // STARTED - registered in TaskManager, requires master notification when finishes
-        // PENDING_CANCEL - registered in TaskManager, doesn't require master notification when finishes
-        // COMPLETED - not registered in TaskManager, notified, waiting for master to remove it from CS so we can remove locally
+        // STARTED - registered in TaskManager, requires cluster-manager notification when finishes
+        // PENDING_CANCEL - registered in TaskManager, doesn't require cluster-manager notification when finishes
+        // COMPLETED - not registered in TaskManager, notified, waiting for cluster-manager to remove it from CS so we can remove locally
 
         // When task finishes if it is marked as STARTED or PENDING_CANCEL it is marked as COMPLETED and unregistered,
-        // If the task was STARTED, the master notification is also triggered (this is handled by unregisterTask() method, which is
+        // If the task was STARTED, the cluster-manager notification is also triggered (this is handled by unregisterTask() method, which is
         // triggered by PersistentTaskListener
 
         if (Objects.equals(tasks, previousTasks) == false || event.nodesChanged()) {
@@ -162,7 +165,7 @@ public void clusterChanged(ClusterChangedEvent event) {
                     );
                     runningTasks.remove(id);
                 } else {
-                    // task is running locally, but master doesn't know about it - that means that the persistent task was removed
+                    // task is running locally, but cluster-manager doesn't know about it - that means that the persistent task was removed
                     // cancel the task without notifying master
                     logger.trace(
                         "Found unregistered persistent task [{}] with id [{}] and allocation id [{}] - cancelling",
@@ -286,7 +289,7 @@ public void onFailure(Exception notificationException) {
     }
 
     /**
-     * Unregisters and then cancels the locally running task using the task manager. No notification to master will be send upon
+     * Unregisters and then cancels the locally running task using the task manager. No notification to cluster-manager will be send upon
      * cancellation.
      */
     private void cancelTask(Long allocationId) {
@@ -322,6 +325,11 @@ public void onFailure(Exception e) {
         }
     }
 
+    /**
+     * The executor status.
+     *
+     * @opensearch.internal
+     */
     public static class Status implements Task.Status {
 
         public static final String NAME = "persistent_executor";
@@ -356,7 +364,7 @@ public void writeTo(StreamOutput out) throws IOException {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/persistent/PersistentTasksService.java b/server/src/main/java/org/opensearch/persistent/PersistentTasksService.java
index a52b623a7a843..53ef6590df192 100644
--- a/server/src/main/java/org/opensearch/persistent/PersistentTasksService.java
+++ b/server/src/main/java/org/opensearch/persistent/PersistentTasksService.java
@@ -33,9 +33,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
 import org.opensearch.client.Client;
@@ -45,17 +44,20 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.function.Predicate;
 
 /**
  * This service is used by persistent tasks and allocated persistent tasks to communicate changes
- * to the master node so that the master can update the cluster state and can track of the states
+ * to the cluster-manager node so that the cluster-manager can update the cluster state and can track of the states
  * of the persistent tasks.
+ *
+ * @opensearch.internal
  */
 public class PersistentTasksService {
 
@@ -74,7 +76,7 @@ public PersistentTasksService(ClusterService clusterService, ThreadPool threadPo
     }
 
     /**
-     * Notifies the master node to create new persistent task and to assign it to a node.
+     * Notifies the cluster-manager node to create new persistent task and to assign it to a node.
      */
     public <Params extends PersistentTaskParams> void sendStartRequest(
         final String taskId,
@@ -89,7 +91,7 @@ public <Params extends PersistentTaskParams> void sendStartRequest(
     }
 
     /**
-     * Notifies the master node about the completion of a persistent task.
+     * Notifies the cluster-manager node about the completion of a persistent task.
      * <p>
      * When {@code failure} is {@code null}, the persistent task is considered as successfully completed.
      */
@@ -118,7 +120,7 @@ void sendCancelRequest(final long taskId, final String reason, final ActionListe
     }
 
     /**
-     * Notifies the master node that the state of a persistent task has changed.
+     * Notifies the cluster-manager node that the state of a persistent task has changed.
      * <p>
      * Persistent task implementers shouldn't call this method directly and use
      * {@link AllocatedPersistentTask#updatePersistentTaskState} instead
@@ -138,7 +140,7 @@ void sendUpdateStateRequest(
     }
 
     /**
-     * Notifies the master node to remove a persistent task from the cluster state
+     * Notifies the cluster-manager node to remove a persistent task from the cluster state
      */
     public void sendRemoveRequest(final String taskId, final ActionListener<PersistentTask<?>> listener) {
         RemovePersistentTaskAction.Request request = new RemovePersistentTaskAction.Request(taskId);
@@ -243,6 +245,11 @@ public void onTimeout(TimeValue timeout) {
         }
     }
 
+    /**
+     * Interface for a class that waits and listens for a persistent task.
+     *
+     * @opensearch.internal
+     */
     public interface WaitForPersistentTaskListener<P extends PersistentTaskParams> extends ActionListener<PersistentTask<P>> {
         default void onTimeout(TimeValue timeout) {
             onFailure(new IllegalStateException("Timed out when waiting for persistent task after " + timeout));
diff --git a/server/src/main/java/org/opensearch/persistent/RemovePersistentTaskAction.java b/server/src/main/java/org/opensearch/persistent/RemovePersistentTaskAction.java
index d35d5fbf70f0a..45fe8917095c3 100644
--- a/server/src/main/java/org/opensearch/persistent/RemovePersistentTaskAction.java
+++ b/server/src/main/java/org/opensearch/persistent/RemovePersistentTaskAction.java
@@ -31,13 +31,12 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -45,14 +44,20 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Transport action to remove a persistent task
+ *
+ * @opensearch.internal
+ */
 public class RemovePersistentTaskAction extends ActionType<PersistentTaskResponse> {
 
     public static final RemovePersistentTaskAction INSTANCE = new RemovePersistentTaskAction();
@@ -62,7 +67,12 @@ private RemovePersistentTaskAction() {
         super(NAME, PersistentTaskResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * The request.
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String taskId;
 
@@ -106,10 +116,12 @@ public int hashCode() {
         }
     }
 
-    public static class RequestBuilder extends MasterNodeOperationRequestBuilder<
-        RemovePersistentTaskAction.Request,
-        PersistentTaskResponse,
-        RemovePersistentTaskAction.RequestBuilder> {
+    /**
+     * The request builder.
+     *
+     * @opensearch.internal
+     */
+    public static class RequestBuilder extends ClusterManagerNodeOperationRequestBuilder<Request, PersistentTaskResponse, RequestBuilder> {
 
         protected RequestBuilder(OpenSearchClient client, RemovePersistentTaskAction action) {
             super(client, action, new Request());
@@ -122,7 +134,12 @@ public final RequestBuilder setTaskId(String taskId) {
 
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, PersistentTaskResponse> {
+    /**
+     * The transport action.
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, PersistentTaskResponse> {
 
         private final PersistentTasksClusterService persistentTasksClusterService;
 
@@ -164,7 +181,7 @@ protected ClusterBlockException checkBlock(Request request, ClusterState state)
         }
 
         @Override
-        protected final void masterOperation(
+        protected final void clusterManagerOperation(
             final Request request,
             ClusterState state,
             final ActionListener<PersistentTaskResponse> listener
diff --git a/server/src/main/java/org/opensearch/persistent/StartPersistentTaskAction.java b/server/src/main/java/org/opensearch/persistent/StartPersistentTaskAction.java
index b5d7885f1e313..c839fb72c4d05 100644
--- a/server/src/main/java/org/opensearch/persistent/StartPersistentTaskAction.java
+++ b/server/src/main/java/org/opensearch/persistent/StartPersistentTaskAction.java
@@ -31,13 +31,12 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -46,8 +45,9 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -58,6 +58,8 @@
 
 /**
  *  This action can be used to add the record for the persistent action to the cluster state.
+ *
+ *  @opensearch.internal
  */
 public class StartPersistentTaskAction extends ActionType<PersistentTaskResponse> {
 
@@ -68,7 +70,12 @@ private StartPersistentTaskAction() {
         super(NAME, PersistentTaskResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * Request for the action.
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String taskId;
 
@@ -161,10 +168,12 @@ public void setParams(PersistentTaskParams params) {
 
     }
 
-    public static class RequestBuilder extends MasterNodeOperationRequestBuilder<
-        StartPersistentTaskAction.Request,
-        PersistentTaskResponse,
-        StartPersistentTaskAction.RequestBuilder> {
+    /**
+     * The request builder.
+     *
+     * @opensearch.internal
+     */
+    public static class RequestBuilder extends ClusterManagerNodeOperationRequestBuilder<Request, PersistentTaskResponse, RequestBuilder> {
 
         protected RequestBuilder(OpenSearchClient client, StartPersistentTaskAction action) {
             super(client, action, new Request());
@@ -187,7 +196,12 @@ public RequestBuilder setRequest(PersistentTaskParams params) {
 
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, PersistentTaskResponse> {
+    /**
+     * The transport action.
+     *
+     * @opensearch.internal
+     */
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, PersistentTaskResponse> {
 
         private final PersistentTasksClusterService persistentTasksClusterService;
 
@@ -240,7 +254,7 @@ protected ClusterBlockException checkBlock(Request request, ClusterState state)
         }
 
         @Override
-        protected final void masterOperation(
+        protected final void clusterManagerOperation(
             final Request request,
             ClusterState state,
             final ActionListener<PersistentTaskResponse> listener
diff --git a/server/src/main/java/org/opensearch/persistent/UpdatePersistentTaskStatusAction.java b/server/src/main/java/org/opensearch/persistent/UpdatePersistentTaskStatusAction.java
index b72e8c963dc43..030b3d231cdd3 100644
--- a/server/src/main/java/org/opensearch/persistent/UpdatePersistentTaskStatusAction.java
+++ b/server/src/main/java/org/opensearch/persistent/UpdatePersistentTaskStatusAction.java
@@ -31,13 +31,12 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.MasterNodeOperationRequestBuilder;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeOperationRequestBuilder;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -45,8 +44,9 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -55,6 +55,11 @@
 
 import static org.opensearch.action.ValidateActions.addValidationError;
 
+/**
+ * Transport action for updating persistent tasks
+ *
+ * @opensearch.internal
+ */
 public class UpdatePersistentTaskStatusAction extends ActionType<PersistentTaskResponse> {
 
     public static final UpdatePersistentTaskStatusAction INSTANCE = new UpdatePersistentTaskStatusAction();
@@ -64,7 +69,12 @@ private UpdatePersistentTaskStatusAction() {
         super(NAME, PersistentTaskResponse::new);
     }
 
-    public static class Request extends MasterNodeRequest<Request> {
+    /**
+     * The action request.
+     *
+     * @opensearch.internal
+     */
+    public static class Request extends ClusterManagerNodeRequest<Request> {
 
         private String taskId;
         private long allocationId = -1L;
@@ -133,10 +143,12 @@ public int hashCode() {
         }
     }
 
-    public static class RequestBuilder extends MasterNodeOperationRequestBuilder<
-        UpdatePersistentTaskStatusAction.Request,
-        PersistentTaskResponse,
-        UpdatePersistentTaskStatusAction.RequestBuilder> {
+    /**
+     * The request builder.
+     *
+     * @opensearch.internal
+     */
+    public static class RequestBuilder extends ClusterManagerNodeOperationRequestBuilder<Request, PersistentTaskResponse, RequestBuilder> {
 
         protected RequestBuilder(OpenSearchClient client, UpdatePersistentTaskStatusAction action) {
             super(client, action, new Request());
@@ -153,7 +165,13 @@ public final RequestBuilder setState(PersistentTaskState state) {
         }
     }
 
-    public static class TransportAction extends TransportMasterNodeAction<Request, PersistentTaskResponse> {
+    /**
+     * The transport action.
+     *
+     * @opensearch.internal
+     */
+
+    public static class TransportAction extends TransportClusterManagerNodeAction<Request, PersistentTaskResponse> {
 
         private final PersistentTasksClusterService persistentTasksClusterService;
 
@@ -195,7 +213,7 @@ protected ClusterBlockException checkBlock(Request request, ClusterState state)
         }
 
         @Override
-        protected final void masterOperation(
+        protected final void clusterManagerOperation(
             final Request request,
             final ClusterState state,
             final ActionListener<PersistentTaskResponse> listener
diff --git a/server/src/main/java/org/opensearch/persistent/decider/AssignmentDecision.java b/server/src/main/java/org/opensearch/persistent/decider/AssignmentDecision.java
index 45d4e643f624b..7b5840324b921 100644
--- a/server/src/main/java/org/opensearch/persistent/decider/AssignmentDecision.java
+++ b/server/src/main/java/org/opensearch/persistent/decider/AssignmentDecision.java
@@ -39,6 +39,8 @@
  * assigning a persistent task to a node of the cluster.
  *
  * @see EnableAssignmentDecider
+ *
+ * @opensearch.internal
  */
 public final class AssignmentDecision {
 
@@ -65,6 +67,11 @@ public String toString() {
         return "assignment decision [type=" + type + ", reason=" + reason + "]";
     }
 
+    /**
+     * The decision.
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         NO(0),
         YES(1);
diff --git a/server/src/main/java/org/opensearch/persistent/decider/EnableAssignmentDecider.java b/server/src/main/java/org/opensearch/persistent/decider/EnableAssignmentDecider.java
index 795fb3b77b9fb..4c306dca758e7 100644
--- a/server/src/main/java/org/opensearch/persistent/decider/EnableAssignmentDecider.java
+++ b/server/src/main/java/org/opensearch/persistent/decider/EnableAssignmentDecider.java
@@ -51,6 +51,8 @@
  * </ul>
  *
  * @see Allocation
+ *
+ * @opensearch.internal
  */
 public class EnableAssignmentDecider {
 
diff --git a/server/src/main/java/org/opensearch/persistent/decider/package-info.java b/server/src/main/java/org/opensearch/persistent/decider/package-info.java
new file mode 100644
index 0000000000000..83f96dc23db19
--- /dev/null
+++ b/server/src/main/java/org/opensearch/persistent/decider/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Persistant Task Decider package. */
+package org.opensearch.persistent.decider;
diff --git a/server/src/main/java/org/opensearch/persistent/package-info.java b/server/src/main/java/org/opensearch/persistent/package-info.java
index 00260b56d2ddb..3eff441642c90 100644
--- a/server/src/main/java/org/opensearch/persistent/package-info.java
+++ b/server/src/main/java/org/opensearch/persistent/package-info.java
@@ -32,12 +32,12 @@
  * In order to be resilient to node restarts, the persistent tasks are using the cluster state instead of a transport service to send
  * requests and responses. The execution is done in six phases:
  * <p>
- * 1. The coordinating node sends an ordinary transport request to the master node to start a new persistent task. This task is handled
+ * 1. The coordinating node sends an ordinary transport request to the cluster-manager node to start a new persistent task. This task is handled
  * by the {@link org.opensearch.persistent.PersistentTasksService}, which is using
  * {@link org.opensearch.persistent.PersistentTasksClusterService} to update cluster state with the record about running persistent
  * task.
  * <p>
- * 2. The master node updates the {@link org.opensearch.persistent.PersistentTasksCustomMetadata} in the cluster state to indicate
+ * 2. The cluster-manager node updates the {@link org.opensearch.persistent.PersistentTasksCustomMetadata} in the cluster state to indicate
  * that there is a new persistent task running in the system.
  * <p>
  * 3. The {@link org.opensearch.persistent.PersistentTasksNodeService} running on every node in the cluster monitors changes in
diff --git a/server/src/main/java/org/opensearch/plugins/ActionPlugin.java b/server/src/main/java/org/opensearch/plugins/ActionPlugin.java
index 31f5159120337..fadf17ef48622 100644
--- a/server/src/main/java/org/opensearch/plugins/ActionPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/ActionPlugin.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.plugins;
 
-import org.opensearch.action.ActionType;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.RequestValidators;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
@@ -43,12 +42,13 @@
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.RestController;
 import org.opensearch.rest.RestHandler;
 import org.opensearch.rest.RestHeaderDefinition;
@@ -72,6 +72,8 @@
  *               new ActionHandler<>(RethrottleAction.INSTANCE, TransportRethrottleAction.class));
  *   }
  * }</pre>
+ *
+ * @opensearch.api
  */
 public interface ActionPlugin {
     /**
@@ -150,6 +152,11 @@ default UnaryOperator<RestHandler> getRestHandlerWrapper(ThreadContext threadCon
         return null;
     }
 
+    /**
+     *  Class responsible for handing Transport Actions
+     *
+     * @opensearch.internal
+     */
     final class ActionHandler<Request extends ActionRequest, Response extends ActionResponse> {
         private final ActionType<Response> action;
         private final Class<? extends TransportAction<Request, Response>> transportAction;
diff --git a/server/src/main/java/org/opensearch/plugins/AnalysisPlugin.java b/server/src/main/java/org/opensearch/plugins/AnalysisPlugin.java
index 8022129df3699..53dcc916b244f 100644
--- a/server/src/main/java/org/opensearch/plugins/AnalysisPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/AnalysisPlugin.java
@@ -72,6 +72,8 @@
  * OpenSearch doesn't have any automatic mechanism to share these components between indexes. If any component is heavy enough to warrant
  * such sharing then it is the Plugin's responsibility to do it in their {@link AnalysisProvider} implementation. We recommend against doing
  * this unless absolutely necessary because it can be difficult to get the caching right given things like behavior changes across versions.
+ *
+ * @opensearch.api
  */
 public interface AnalysisPlugin {
     /**
diff --git a/server/src/main/java/org/opensearch/plugins/CircuitBreakerPlugin.java b/server/src/main/java/org/opensearch/plugins/CircuitBreakerPlugin.java
index 01aaddf96a70d..7e7345811246f 100644
--- a/server/src/main/java/org/opensearch/plugins/CircuitBreakerPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/CircuitBreakerPlugin.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.plugins;
 
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.breaker.BreakerSettings;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 
 /**
  * An extension point for {@link Plugin} implementations to add custom circuit breakers
+ *
+ * @opensearch.api
  */
 public interface CircuitBreakerPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/ClusterPlugin.java b/server/src/main/java/org/opensearch/plugins/ClusterPlugin.java
index 54a94d540ce32..c2e147b86d17f 100644
--- a/server/src/main/java/org/opensearch/plugins/ClusterPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/ClusterPlugin.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.plugins;
 
+import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.ExistingShardsAllocator;
 import org.opensearch.cluster.routing.allocation.allocator.ShardsAllocator;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDecider;
@@ -45,6 +46,8 @@
 
 /**
  * An extension point for {@link Plugin} implementations to customer behavior of cluster management.
+ *
+ * @opensearch.api
  */
 public interface ClusterPlugin {
 
@@ -84,7 +87,19 @@ default Map<String, ExistingShardsAllocator> getExistingShardsAllocators() {
 
     /**
      * Called when the node is started
+     *
+     * DEPRECATED: Use {@link #onNodeStarted(DiscoveryNode)} for newer implementations.
      */
+    @Deprecated
     default void onNodeStarted() {}
 
+    /**
+     * Called when node is started. DiscoveryNode argument is passed to allow referring localNode value inside plugin
+     *
+     * @param localNode local Node info
+     */
+    default void onNodeStarted(DiscoveryNode localNode) {
+        onNodeStarted();
+    }
+
 }
diff --git a/server/src/main/java/org/opensearch/plugins/CryptoKeyProviderPlugin.java b/server/src/main/java/org/opensearch/plugins/CryptoKeyProviderPlugin.java
new file mode 100644
index 0000000000000..47dc75c7c908a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/CryptoKeyProviderPlugin.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.crypto.MasterKeyProvider;
+
+/**
+ * Crypto plugin to provide support for custom key providers.
+ * @opensearch.api
+ */
+@ExperimentalApi
+public interface CryptoKeyProviderPlugin {
+
+    /**
+     * Every call to this method should return a new key provider.
+     * @param cryptoMetadata These are crypto settings needed for creation of a new key provider.
+     * @return master key provider.
+     */
+    MasterKeyProvider createKeyProvider(CryptoMetadata cryptoMetadata);
+
+    /**
+     * One crypto plugin extension implementation refers to a unique key provider type.
+     * @return key provider type
+     */
+    String type();
+}
diff --git a/server/src/main/java/org/opensearch/plugins/CryptoPlugin.java b/server/src/main/java/org/opensearch/plugins/CryptoPlugin.java
new file mode 100644
index 0000000000000..ad348d07e23d3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/CryptoPlugin.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.MasterKeyProvider;
+
+/**
+ * Crypto plugin to provide encryption and decryption support.
+ * @opensearch.api
+ */
+@ExperimentalApi
+public interface CryptoPlugin<T, U> {
+
+    /**
+     * To create a crypto handler for handling encryption and decryption ops.
+     * @param keyProvider key provider instance to provide keys used in encrypting data.
+     * @param keyProviderName Name of key provider to distinguish between multiple instances created with different
+     *                        configurations of same keyProviderType.
+     * @param keyProviderType Unique type of key provider to distinguish between different key provider implementations.
+     * @param onClose Closes key provider or other clean up operations on close.
+     * @return crypto handler instance.
+     */
+    CryptoHandler<T, U> getOrCreateCryptoHandler(
+        MasterKeyProvider keyProvider,
+        String keyProviderName,
+        String keyProviderType,
+        Runnable onClose
+    );
+}
diff --git a/server/src/main/java/org/opensearch/plugins/DiscoveryPlugin.java b/server/src/main/java/org/opensearch/plugins/DiscoveryPlugin.java
index 764e249474d9b..bca72942bd70e 100644
--- a/server/src/main/java/org/opensearch/plugins/DiscoveryPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/DiscoveryPlugin.java
@@ -37,6 +37,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.transport.TransportService;
 
@@ -57,6 +58,8 @@
  *     }
  * }
  * </pre>
+ *
+ * @opensearch.api
  */
 public interface DiscoveryPlugin {
 
@@ -84,7 +87,7 @@ default NetworkService.CustomNameResolver getCustomNameResolver(Settings setting
      * (see {@link org.opensearch.discovery.DiscoveryModule#DISCOVERY_SEED_PROVIDERS_SETTING}), and
      * the value is a supplier to construct the host provider when it is selected for use.
      *
-     * @param transportService Use to form the {@link org.opensearch.common.transport.TransportAddress} portion
+     * @param transportService Use to form the {@link TransportAddress} portion
      *                         of a {@link org.opensearch.cluster.node.DiscoveryNode}
      * @param networkService Use to find the publish host address of the current node
      */
diff --git a/server/src/main/java/org/opensearch/plugins/EnginePlugin.java b/server/src/main/java/org/opensearch/plugins/EnginePlugin.java
index 31844dbdaec2b..92ae2ff9cd661 100644
--- a/server/src/main/java/org/opensearch/plugins/EnginePlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/EnginePlugin.java
@@ -45,6 +45,8 @@
 
 /**
  * A plugin that provides alternative engine implementations.
+ *
+ * @opensearch.api
  */
 public interface EnginePlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/ExtensiblePlugin.java b/server/src/main/java/org/opensearch/plugins/ExtensiblePlugin.java
index 9cab282910599..4dd4010383934 100644
--- a/server/src/main/java/org/opensearch/plugins/ExtensiblePlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/ExtensiblePlugin.java
@@ -39,9 +39,16 @@
  *
  * This class provides a callback for extensible plugins to be informed of other plugins
  * which extend them.
+ *
+ * @opensearch.api
  */
 public interface ExtensiblePlugin {
 
+    /**
+     * Extension point for external plugins to be extendable
+     *
+     * @opensearch.api
+     */
     interface ExtensionLoader {
         /**
          * Load extensions of the type from all extending plugins. The concrete extensions must have either a no-arg constructor
diff --git a/server/src/main/java/org/opensearch/plugins/ExtensionAwarePlugin.java b/server/src/main/java/org/opensearch/plugins/ExtensionAwarePlugin.java
new file mode 100644
index 0000000000000..c8426bc964287
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/ExtensionAwarePlugin.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.common.settings.Setting;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Plugin that provides extra settings for extensions
+ *
+ * @opensearch.experimental
+ */
+public interface ExtensionAwarePlugin {
+
+    /**
+     * Returns a list of additional {@link Setting} definitions that this plugin adds for extensions
+     */
+    default List<Setting<?>> getExtensionSettings() {
+        return Collections.emptyList();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/plugins/IdentityPlugin.java b/server/src/main/java/org/opensearch/plugins/IdentityPlugin.java
new file mode 100644
index 0000000000000..00f3f8aff585c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/IdentityPlugin.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.TokenManager;
+
+/**
+ * Plugin that provides identity and access control for OpenSearch
+ *
+ * @opensearch.experimental
+ */
+public interface IdentityPlugin {
+
+    /**
+     * Get the current subject
+     *
+     * Should never return null
+     * */
+    public Subject getSubject();
+
+    /**
+     * Get the Identity Plugin's token manager implementation
+     *
+     * Should never return null
+     */
+    public TokenManager getTokenManager();
+}
diff --git a/server/src/main/java/org/opensearch/plugins/IndexStorePlugin.java b/server/src/main/java/org/opensearch/plugins/IndexStorePlugin.java
index 0a6e6a9ff3b67..2f549fec54759 100644
--- a/server/src/main/java/org/opensearch/plugins/IndexStorePlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/IndexStorePlugin.java
@@ -46,6 +46,8 @@
 
 /**
  * A plugin that provides alternative directory implementations.
+ *
+ * @opensearch.api
  */
 public interface IndexStorePlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/IngestPlugin.java b/server/src/main/java/org/opensearch/plugins/IngestPlugin.java
index d04a3c3add88c..dfc11aa8eea55 100644
--- a/server/src/main/java/org/opensearch/plugins/IngestPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/IngestPlugin.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.plugins;
 
+import org.opensearch.ingest.Processor;
+
 import java.util.Collections;
 import java.util.Map;
 
-import org.opensearch.ingest.Processor;
-
 /**
  * An extension point for {@link Plugin} implementations to add custom ingest processors
+ *
+ * @opensearch.api
  */
 public interface IngestPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/MapperPlugin.java b/server/src/main/java/org/opensearch/plugins/MapperPlugin.java
index d31aafb863dc6..ff6daf1b720f6 100644
--- a/server/src/main/java/org/opensearch/plugins/MapperPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/MapperPlugin.java
@@ -42,6 +42,8 @@
 
 /**
  * An extension point for {@link Plugin} implementations to add custom mappers
+ *
+ * @opensearch.api
  */
 public interface MapperPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/MetadataUpgrader.java b/server/src/main/java/org/opensearch/plugins/MetadataUpgrader.java
index 997fc88e5dbd9..37419b08f4b1e 100644
--- a/server/src/main/java/org/opensearch/plugins/MetadataUpgrader.java
+++ b/server/src/main/java/org/opensearch/plugins/MetadataUpgrader.java
@@ -42,6 +42,8 @@
 
 /**
  * Upgrades {@link Metadata} on startup on behalf of installed {@link Plugin}s
+ *
+ * @opensearch.api
  */
 public class MetadataUpgrader {
     public final UnaryOperator<Map<String, IndexTemplateMetadata>> indexTemplateMetadataUpgraders;
diff --git a/server/src/main/java/org/opensearch/plugins/NetworkPlugin.java b/server/src/main/java/org/opensearch/plugins/NetworkPlugin.java
index b53718fccf42a..07df40bafe6a1 100644
--- a/server/src/main/java/org/opensearch/plugins/NetworkPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/NetworkPlugin.java
@@ -31,27 +31,30 @@
 
 package org.opensearch.plugins;
 
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.function.Supplier;
-
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpServerTransport;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportInterceptor;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Supplier;
+
 /**
  * Plugin for extending network and transport related classes
+ *
+ * @opensearch.api
  */
 public interface NetworkPlugin {
 
@@ -80,7 +83,8 @@ default Map<String, Supplier<Transport>> getTransports(
         PageCacheRecycler pageCacheRecycler,
         CircuitBreakerService circuitBreakerService,
         NamedWriteableRegistry namedWriteableRegistry,
-        NetworkService networkService
+        NetworkService networkService,
+        Tracer tracer
     ) {
         return Collections.emptyMap();
     }
@@ -98,7 +102,8 @@ default Map<String, Supplier<HttpServerTransport>> getHttpTransports(
         NamedXContentRegistry xContentRegistry,
         NetworkService networkService,
         HttpServerTransport.Dispatcher dispatcher,
-        ClusterSettings clusterSettings
+        ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         return Collections.emptyMap();
     }
diff --git a/server/src/main/java/org/opensearch/plugins/PersistentTaskPlugin.java b/server/src/main/java/org/opensearch/plugins/PersistentTaskPlugin.java
index 61cb519f0546d..5eb200f47422d 100644
--- a/server/src/main/java/org/opensearch/plugins/PersistentTaskPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/PersistentTaskPlugin.java
@@ -43,6 +43,8 @@
 
 /**
  * Plugin for registering persistent tasks executors.
+ *
+ * @opensearch.api
  */
 public interface PersistentTaskPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/Platforms.java b/server/src/main/java/org/opensearch/plugins/Platforms.java
index e9c767ed00880..86a442d593b47 100644
--- a/server/src/main/java/org/opensearch/plugins/Platforms.java
+++ b/server/src/main/java/org/opensearch/plugins/Platforms.java
@@ -39,6 +39,8 @@
 
 /**
  * Encapsulates platform-dependent methods for handling native components of plugins.
+ *
+ * @opensearch.api
  */
 public class Platforms {
 
diff --git a/server/src/main/java/org/opensearch/plugins/Plugin.java b/server/src/main/java/org/opensearch/plugins/Plugin.java
index 9a7dcbd6a78f6..0743cd3807eff 100644
--- a/server/src/main/java/org/opensearch/plugins/Plugin.java
+++ b/server/src/main/java/org/opensearch/plugins/Plugin.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.plugins;
 
-import org.opensearch.watcher.ResourceWatcherService;
 import org.opensearch.bootstrap.BootstrapCheck;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
@@ -41,15 +40,16 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.component.LifecycleComponent;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.inject.Module;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.SettingUpgrader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexModule;
@@ -58,6 +58,7 @@
 import org.opensearch.script.ScriptService;
 import org.opensearch.threadpool.ExecutorBuilder;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.watcher.ResourceWatcherService;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -86,7 +87,10 @@
  * <li>{@link SearchPlugin}
  * <li>{@link ReloadablePlugin}
  * </ul>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public abstract class Plugin implements Closeable {
 
     /**
diff --git a/server/src/main/java/org/opensearch/plugins/PluginInfo.java b/server/src/main/java/org/opensearch/plugins/PluginInfo.java
index c4867f7a07dc4..25276c39c9b08 100644
--- a/server/src/main/java/org/opensearch/plugins/PluginInfo.java
+++ b/server/src/main/java/org/opensearch/plugins/PluginInfo.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.Version;
 import org.opensearch.bootstrap.JarHell;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -56,6 +56,8 @@
 
 /**
  * An in-memory representation of the plugin descriptor.
+ *
+ * @opensearch.api
  */
 public class PluginInfo implements Writeable, ToXContentObject {
 
@@ -152,7 +154,7 @@ public PluginInfo(final StreamInput in) throws IOException {
         this.name = in.readString();
         this.description = in.readString();
         this.version = in.readString();
-        this.opensearchVersion = Version.readVersion(in);
+        this.opensearchVersion = in.readVersion();
         this.javaVersion = in.readString();
         this.classname = in.readString();
         if (in.getVersion().onOrAfter(Version.V_1_1_0)) {
@@ -169,7 +171,7 @@ public void writeTo(final StreamOutput out) throws IOException {
         out.writeString(name);
         out.writeString(description);
         out.writeString(version);
-        Version.writeVersion(opensearchVersion, out);
+        out.writeVersion(opensearchVersion);
         out.writeString(javaVersion);
         out.writeString(classname);
         if (out.getVersion().onOrAfter(Version.V_1_1_0)) {
diff --git a/server/src/main/java/org/opensearch/plugins/PluginLoaderIndirection.java b/server/src/main/java/org/opensearch/plugins/PluginLoaderIndirection.java
index e62f46038e8ef..199784d1f7630 100644
--- a/server/src/main/java/org/opensearch/plugins/PluginLoaderIndirection.java
+++ b/server/src/main/java/org/opensearch/plugins/PluginLoaderIndirection.java
@@ -37,6 +37,8 @@
 /**
  * This class exists solely as an intermediate layer to avoid causing PluginsService
  * to load ExtendedPluginsClassLoader when used in the transport client.
+ *
+ * @opensearch.api
  */
 class PluginLoaderIndirection {
 
diff --git a/server/src/main/java/org/opensearch/plugins/PluginSecurity.java b/server/src/main/java/org/opensearch/plugins/PluginSecurity.java
index 6665d8088c4ff..e7d92016d4082 100644
--- a/server/src/main/java/org/opensearch/plugins/PluginSecurity.java
+++ b/server/src/main/java/org/opensearch/plugins/PluginSecurity.java
@@ -36,7 +36,7 @@
 import org.opensearch.cli.Terminal;
 import org.opensearch.cli.Terminal.Verbosity;
 import org.opensearch.cli.UserException;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -54,6 +54,11 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * Security Policy for Plugins
+ *
+ * @opensearch.api
+ */
 class PluginSecurity {
 
     /**
diff --git a/server/src/main/java/org/opensearch/plugins/PluginsService.java b/server/src/main/java/org/opensearch/plugins/PluginsService.java
index 4ef2dc4617de9..47195a0264750 100644
--- a/server/src/main/java/org/opensearch/plugins/PluginsService.java
+++ b/server/src/main/java/org/opensearch/plugins/PluginsService.java
@@ -43,15 +43,15 @@
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.info.PluginsAndModules;
 import org.opensearch.bootstrap.JarHell;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.component.LifecycleComponent;
 import org.opensearch.common.inject.Module;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.service.ReportingService;
 import org.opensearch.index.IndexModule;
-import org.opensearch.node.ReportingService;
 import org.opensearch.threadpool.ExecutorBuilder;
 import org.opensearch.transport.TransportSettings;
 
@@ -81,8 +81,13 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.io.FileSystemUtils.isAccessibleDirectory;
+import static org.opensearch.core.util.FileSystemUtils.isAccessibleDirectory;
 
+/**
+ * Service responsible for loading plugins and modules (internal and external)
+ *
+ * @opensearch.internal
+ */
 public class PluginsService implements ReportingService<PluginsAndModules> {
 
     private static final Logger logger = LogManager.getLogger(PluginsService.class);
@@ -300,6 +305,7 @@ public Collection<Class<? extends LifecycleComponent>> getGuiceServiceClasses()
     }
 
     public void onIndexModule(IndexModule indexModule) {
+        logger.info("PluginService:onIndexModule index:" + indexModule.getIndex());
         for (Tuple<PluginInfo, Plugin> plugin : plugins) {
             plugin.v2().onIndexModule(indexModule);
         }
diff --git a/server/src/main/java/org/opensearch/plugins/ReloadablePlugin.java b/server/src/main/java/org/opensearch/plugins/ReloadablePlugin.java
index 6b9194129dd5f..7a0854f2c89b9 100644
--- a/server/src/main/java/org/opensearch/plugins/ReloadablePlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/ReloadablePlugin.java
@@ -40,6 +40,8 @@
  * is reloaded it might rebuild any internal members. Plugins usually implement
  * this interface in order to reread the values of {@code SecureSetting}s and
  * then rebuild any dependent internal members.
+ *
+ * @opensearch.api
  */
 public interface ReloadablePlugin {
     /**
diff --git a/server/src/main/java/org/opensearch/plugins/RepositoryPlugin.java b/server/src/main/java/org/opensearch/plugins/RepositoryPlugin.java
index 2c52961bb5f32..189ba3cfc16ab 100644
--- a/server/src/main/java/org/opensearch/plugins/RepositoryPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/RepositoryPlugin.java
@@ -33,7 +33,7 @@
 package org.opensearch.plugins;
 
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.Repository;
@@ -43,6 +43,8 @@
 
 /**
  * An extension point for {@link Plugin} implementations to add custom snapshot repositories.
+ *
+ * @opensearch.api
  */
 public interface RepositoryPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/ScriptPlugin.java b/server/src/main/java/org/opensearch/plugins/ScriptPlugin.java
index 85f75f9940591..51f4ab3128cee 100644
--- a/server/src/main/java/org/opensearch/plugins/ScriptPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/ScriptPlugin.java
@@ -31,17 +31,19 @@
 
 package org.opensearch.plugins;
 
+import org.opensearch.common.settings.Settings;
+import org.opensearch.script.ScriptContext;
+import org.opensearch.script.ScriptEngine;
+
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
-import org.opensearch.common.settings.Settings;
-import org.opensearch.script.ScriptContext;
-import org.opensearch.script.ScriptEngine;
-
 /**
  * An additional extension point for {@link Plugin}s that extends OpenSearch's scripting functionality.
+ *
+ * @opensearch.api
  */
 public interface ScriptPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/SearchPipelinePlugin.java b/server/src/main/java/org/opensearch/plugins/SearchPipelinePlugin.java
new file mode 100644
index 0000000000000..d2ef2b65c5944
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/SearchPipelinePlugin.java
@@ -0,0 +1,139 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.client.Client;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.index.analysis.AnalysisRegistry;
+import org.opensearch.script.ScriptService;
+import org.opensearch.search.pipeline.Processor;
+import org.opensearch.search.pipeline.SearchPhaseResultsProcessor;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.search.pipeline.SearchRequestProcessor;
+import org.opensearch.search.pipeline.SearchResponseProcessor;
+import org.opensearch.threadpool.Scheduler;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.function.BiFunction;
+import java.util.function.Consumer;
+import java.util.function.LongSupplier;
+
+/**
+ * An extension point for {@link Plugin} implementation to add custom search pipeline processors.
+ *
+ * @opensearch.api
+ */
+public interface SearchPipelinePlugin {
+    /**
+     * Returns additional search pipeline request processor types added by this plugin.
+     *
+     * The key of the returned {@link Map} is the unique name for the processor which is specified
+     * in pipeline configurations, and the value is a {@link org.opensearch.search.pipeline.Processor.Factory}
+     * to create the processor from a given pipeline configuration.
+     */
+    default Map<String, Processor.Factory<SearchRequestProcessor>> getRequestProcessors(Parameters parameters) {
+        return Collections.emptyMap();
+    }
+
+    /**
+     * Returns additional search pipeline response processor types added by this plugin.
+     *
+     * The key of the returned {@link Map} is the unique name for the processor which is specified
+     * in pipeline configurations, and the value is a {@link org.opensearch.search.pipeline.Processor.Factory}
+     * to create the processor from a given pipeline configuration.
+     */
+    default Map<String, Processor.Factory<SearchResponseProcessor>> getResponseProcessors(Parameters parameters) {
+        return Collections.emptyMap();
+    }
+
+    /**
+     * Returns additional search pipeline search phase results processor types added by this plugin.
+     *
+     * The key of the returned {@link Map} is the unique name for the processor which is specified
+     * in pipeline configurations, and the value is a {@link org.opensearch.search.pipeline.Processor.Factory}
+     * to create the processor from a given pipeline configuration.
+     */
+    default Map<String, Processor.Factory<SearchPhaseResultsProcessor>> getSearchPhaseResultsProcessors(Parameters parameters) {
+        return Collections.emptyMap();
+    }
+
+    /**
+     * Infrastructure class that holds services that can be used by processor factories to create processor instances
+     * and that gets passed around to all {@link SearchPipelinePlugin}s.
+     */
+    class Parameters {
+
+        /**
+         * Useful to provide access to the node's environment like config directory to processor factories.
+         */
+        public final Environment env;
+
+        /**
+         * Provides processors script support.
+         */
+        public final ScriptService scriptService;
+
+        /**
+         * Provide analyzer support
+         */
+        public final AnalysisRegistry analysisRegistry;
+
+        /**
+         * Allows processors to read headers set by {@link org.opensearch.action.support.ActionFilter}
+         * instances that have run while handling the current search.
+         */
+        public final ThreadContext threadContext;
+
+        public final LongSupplier relativeTimeSupplier;
+
+        public final SearchPipelineService searchPipelineService;
+
+        public final Consumer<Runnable> genericExecutor;
+
+        public final NamedXContentRegistry namedXContentRegistry;
+
+        /**
+         * Provides scheduler support
+         */
+        public final BiFunction<Long, Runnable, Scheduler.ScheduledCancellable> scheduler;
+
+        /**
+         * Provides access to the node's cluster client
+         */
+        public final Client client;
+
+        public Parameters(
+            Environment env,
+            ScriptService scriptService,
+            AnalysisRegistry analysisRegistry,
+            ThreadContext threadContext,
+            LongSupplier relativeTimeSupplier,
+            BiFunction<Long, Runnable, Scheduler.ScheduledCancellable> scheduler,
+            SearchPipelineService searchPipelineService,
+            Client client,
+            Consumer<Runnable> genericExecutor,
+            NamedXContentRegistry namedXContentRegistry
+        ) {
+            this.env = env;
+            this.scriptService = scriptService;
+            this.threadContext = threadContext;
+            this.analysisRegistry = analysisRegistry;
+            this.relativeTimeSupplier = relativeTimeSupplier;
+            this.scheduler = scheduler;
+            this.searchPipelineService = searchPipelineService;
+            this.client = client;
+            this.genericExecutor = genericExecutor;
+            this.namedXContentRegistry = namedXContentRegistry;
+        }
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/plugins/SearchPlugin.java b/server/src/main/java/org/opensearch/plugins/SearchPlugin.java
index f650a1ce5512f..a252c46645097 100644
--- a/server/src/main/java/org/opensearch/plugins/SearchPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/SearchPlugin.java
@@ -36,15 +36,15 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.Sort;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.search.function.ScoreFunction;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryParser;
 import org.opensearch.index.query.functionscore.ScoreFunctionBuilder;
@@ -55,6 +55,9 @@
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.PipelineAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregation;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregationParsingFunction;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceBuilder;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTerms;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 import org.opensearch.search.aggregations.pipeline.MovAvgModel;
@@ -87,6 +90,8 @@
 
 /**
  * Plugin for extending search time behavior.
+ *
+ * @opensearch.api
  */
 public interface SearchPlugin {
     /**
@@ -170,6 +175,15 @@ default List<Consumer<ValuesSourceRegistry.Builder>> getAggregationExtentions()
         return emptyList();
     }
 
+    /**
+     * Allows plugins to register new Aggregation in the {@link CompositeAggregation}.
+     *
+     * @return A {@link List} of {@link CompositeAggregationSpec}
+     */
+    default List<CompositeAggregationSpec> getCompositeAggregations() {
+        return emptyList();
+    }
+
     /**
      * The new {@link PipelineAggregator}s added by this plugin.
      */
@@ -530,6 +544,76 @@ public AggregationSpec setAggregatorRegistrar(Consumer<ValuesSourceRegistry.Buil
         }
     }
 
+    /**
+     * Specification for including an aggregation as a part of Composite Aggregation.
+     */
+    class CompositeAggregationSpec {
+        private final Consumer<ValuesSourceRegistry.Builder> aggregatorRegistrar;
+        private final Class<?> valueSourceBuilderClass;
+        @Deprecated
+        /** This is added for backward compatibility, you don't need to set it, as we use aggregationType instead of
+         * byte code
+         */
+        private Byte byteCode;
+        private final CompositeAggregationParsingFunction parsingFunction;
+        private final String aggregationType;
+        private final Writeable.Reader<? extends CompositeValuesSourceBuilder<?>> reader;
+
+        /**
+         * Specification for registering an aggregation in Composite Aggregation
+         *
+         * @param aggregatorRegistrar function to register the
+         * {@link org.opensearch.search.aggregations.support.ValuesSource} to aggregator mappings for Composite
+         *                            aggregation
+         * @param valueSourceBuilderClass ValueSourceBuilder class name which is building the aggregation
+         * @param byteCode byte code which is used in serialisation and de-serialisation to indentify which
+         *                 aggregation builder to use
+         * @param reader Typically, a reference to a constructor that takes a {@link StreamInput}, which is
+         *               registered with the aggregation
+         * @param parsingFunction a reference function which will be used to parse the Aggregation input.
+         * @param aggregationType a {@link String} defined in the AggregationBuilder as type.
+         */
+        public CompositeAggregationSpec(
+            final Consumer<ValuesSourceRegistry.Builder> aggregatorRegistrar,
+            final Class<? extends CompositeValuesSourceBuilder<?>> valueSourceBuilderClass,
+            final Byte byteCode,
+            final Writeable.Reader<? extends CompositeValuesSourceBuilder<?>> reader,
+            final CompositeAggregationParsingFunction parsingFunction,
+            final String aggregationType
+        ) {
+            this.aggregatorRegistrar = aggregatorRegistrar;
+            this.valueSourceBuilderClass = valueSourceBuilderClass;
+            this.byteCode = byteCode;
+            this.parsingFunction = parsingFunction;
+            this.aggregationType = aggregationType;
+            this.reader = reader;
+        }
+
+        public Consumer<ValuesSourceRegistry.Builder> getAggregatorRegistrar() {
+            return aggregatorRegistrar;
+        }
+
+        public Class<?> getValueSourceBuilderClass() {
+            return valueSourceBuilderClass;
+        }
+
+        public Byte getByteCode() {
+            return byteCode;
+        }
+
+        public CompositeAggregationParsingFunction getParsingFunction() {
+            return parsingFunction;
+        }
+
+        public String getAggregationType() {
+            return aggregationType;
+        }
+
+        public Writeable.Reader<? extends CompositeValuesSourceBuilder<?>> getReader() {
+            return reader;
+        }
+    }
+
     /**
      * Specification for a {@link PipelineAggregator}.
      */
diff --git a/server/src/main/java/org/opensearch/plugins/SystemIndexPlugin.java b/server/src/main/java/org/opensearch/plugins/SystemIndexPlugin.java
index b7ff72fd231a6..4937a5ed091dc 100644
--- a/server/src/main/java/org/opensearch/plugins/SystemIndexPlugin.java
+++ b/server/src/main/java/org/opensearch/plugins/SystemIndexPlugin.java
@@ -41,6 +41,8 @@
 /**
  * Plugin for defining system indices. Extends {@link ActionPlugin} because system indices must be accessed via APIs
  * added by the plugin that owns the system index, rather than standard APIs.
+ *
+ * @opensearch.api
  */
 public interface SystemIndexPlugin extends ActionPlugin {
 
diff --git a/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java b/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java
new file mode 100644
index 0000000000000..3fc28713b63d5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+
+import java.util.Optional;
+
+/**
+ * Plugin for extending telemetry related classes
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public interface TelemetryPlugin {
+
+    Optional<Telemetry> getTelemetry(TelemetrySettings telemetrySettings);
+
+    String getName();
+
+}
diff --git a/server/src/main/java/org/opensearch/plugins/spi/NamedXContentProvider.java b/server/src/main/java/org/opensearch/plugins/spi/NamedXContentProvider.java
index ddbf88965f716..334ae5ad18ae5 100644
--- a/server/src/main/java/org/opensearch/plugins/spi/NamedXContentProvider.java
+++ b/server/src/main/java/org/opensearch/plugins/spi/NamedXContentProvider.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.plugins.spi;
 
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 
 import java.util.List;
 
 /**
  * Provides named XContent parsers.
+ *
+ * @opensearch.api
  */
 public interface NamedXContentProvider {
 
diff --git a/server/src/main/java/org/opensearch/repositories/FilterRepository.java b/server/src/main/java/org/opensearch/repositories/FilterRepository.java
index 09f3b0ae223d5..0c5cdf24526cb 100644
--- a/server/src/main/java/org/opensearch/repositories/FilterRepository.java
+++ b/server/src/main/java/org/opensearch/repositories/FilterRepository.java
@@ -33,19 +33,21 @@
 
 import org.apache.lucene.index.IndexCommit;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
@@ -57,6 +59,11 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+/**
+ * Repository that is filtered
+ *
+ * @opensearch.internal
+ */
 public class FilterRepository implements Repository {
 
     private final Repository in;
@@ -136,6 +143,16 @@ public long getRestoreThrottleTimeInNanos() {
         return in.getRestoreThrottleTimeInNanos();
     }
 
+    @Override
+    public long getRemoteUploadThrottleTimeInNanos() {
+        return in.getRemoteUploadThrottleTimeInNanos();
+    }
+
+    @Override
+    public long getRemoteDownloadThrottleTimeInNanos() {
+        return in.getRemoteDownloadThrottleTimeInNanos();
+    }
+
     @Override
     public String startVerification() {
         return in.startVerification();
@@ -156,6 +173,11 @@ public boolean isReadOnly() {
         return in.isReadOnly();
     }
 
+    @Override
+    public boolean isSystemRepository() {
+        return in.isSystemRepository();
+    }
+
     @Override
     public void snapshotShard(
         Store store,
@@ -183,6 +205,31 @@ public void snapshotShard(
         );
     }
 
+    @Override
+    public void snapshotRemoteStoreIndexShard(
+        Store store,
+        SnapshotId snapshotId,
+        IndexId indexId,
+        IndexCommit snapshotIndexCommit,
+        String shardStateIdentifier,
+        IndexShardSnapshotStatus snapshotStatus,
+        long primaryTerm,
+        long startTime,
+        ActionListener<String> listener
+    ) {
+        in.snapshotRemoteStoreIndexShard(
+            store,
+            snapshotId,
+            indexId,
+            snapshotIndexCommit,
+            shardStateIdentifier,
+            snapshotStatus,
+            primaryTerm,
+            startTime,
+            listener
+        );
+    }
+
     @Override
     public void restoreShard(
         Store store,
@@ -195,6 +242,15 @@ public void restoreShard(
         in.restoreShard(store, snapshotId, indexId, snapshotShardId, recoveryState, listener);
     }
 
+    @Override
+    public RemoteStoreShardShallowCopySnapshot getRemoteStoreShallowCopyShardMetadata(
+        SnapshotId snapshotId,
+        IndexId indexId,
+        ShardId snapshotShardId
+    ) {
+        return in.getRemoteStoreShallowCopyShardMetadata(snapshotId, indexId, snapshotShardId);
+    }
+
     @Override
     public IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, IndexId indexId, ShardId shardId) {
         return in.getShardSnapshotStatus(snapshotId, indexId, shardId);
@@ -214,6 +270,18 @@ public void executeConsistentStateUpdate(
         in.executeConsistentStateUpdate(createUpdateTask, source, onFailure);
     }
 
+    @Override
+    public void cloneRemoteStoreIndexShardSnapshot(
+        SnapshotId source,
+        SnapshotId target,
+        RepositoryShardId shardId,
+        String shardGeneration,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<String> listener
+    ) {
+        in.cloneRemoteStoreIndexShardSnapshot(source, target, shardId, shardGeneration, remoteStoreLockManagerFactory, listener);
+    }
+
     @Override
     public void cloneShardSnapshot(
         SnapshotId source,
diff --git a/server/src/main/java/org/opensearch/repositories/IndexId.java b/server/src/main/java/org/opensearch/repositories/IndexId.java
index 02cf745a455e9..0b0644ce932e5 100644
--- a/server/src/main/java/org/opensearch/repositories/IndexId.java
+++ b/server/src/main/java/org/opensearch/repositories/IndexId.java
@@ -32,19 +32,21 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Represents a single snapshotted index in the repository.
+ *
+ * @opensearch.internal
  */
 public final class IndexId implements Writeable, ToXContentObject {
     protected static final String NAME = "name";
diff --git a/server/src/main/java/org/opensearch/repositories/IndexMetaDataGenerations.java b/server/src/main/java/org/opensearch/repositories/IndexMetaDataGenerations.java
index 4ea0217c5870f..afabf4ebfdb58 100644
--- a/server/src/main/java/org/opensearch/repositories/IndexMetaDataGenerations.java
+++ b/server/src/main/java/org/opensearch/repositories/IndexMetaDataGenerations.java
@@ -49,6 +49,8 @@
  * {@link org.opensearch.repositories.blobstore.BlobStoreRepository#finalizeSnapshot} the identifier for an instance of
  * {@link IndexMetadata} should be computed and then used to check if it already exists in the repository via
  * {@link #getIndexMetaBlobId(String)}.
+ *
+ * @opensearch.internal
  */
 public final class IndexMetaDataGenerations {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoriesModule.java b/server/src/main/java/org/opensearch/repositories/RepositoriesModule.java
index 228c62c353355..cc4d3c006d84c 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoriesModule.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoriesModule.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.RepositoryPlugin;
@@ -49,6 +49,8 @@
 
 /**
  * Sets up classes for Snapshot/Restore.
+ *
+ * @opensearch.internal
  */
 public final class RepositoriesModule {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoriesService.java b/server/src/main/java/org/opensearch/repositories/RepositoriesService.java
index e7c5804f458a0..72266c053a1ae 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoriesService.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoriesService.java
@@ -35,8 +35,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
+import org.opensearch.Version;
 import org.opensearch.action.ActionRunnable;
+import org.opensearch.action.admin.cluster.crypto.CryptoSettings;
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryRequest;
 import org.opensearch.action.admin.cluster.repositories.put.PutRepositoryRequest;
 import org.opensearch.cluster.AckedClusterStateUpdateTask;
@@ -48,20 +49,25 @@
 import org.opensearch.cluster.SnapshotDeletionsInProgress;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
+import org.opensearch.cluster.metadata.CryptoMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 import org.opensearch.repositories.blobstore.MeteredBlobStoreRepository;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -77,9 +83,15 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY;
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.SYSTEM_REPOSITORY_SETTING;
+
 /**
  * Service responsible for maintaining and providing access to snapshot repositories on nodes.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class RepositoriesService extends AbstractLifecycleComponent implements ClusterStateApplier {
 
     private static final Logger logger = LogManager.getLogger(RepositoriesService.class);
@@ -109,6 +121,8 @@ public class RepositoriesService extends AbstractLifecycleComponent implements C
     private final Map<String, Repository> internalRepositories = ConcurrentCollections.newConcurrentMap();
     private volatile Map<String, Repository> repositories = Collections.emptyMap();
     private final RepositoriesStatsArchive repositoriesStatsArchive;
+    private final ClusterManagerTaskThrottler.ThrottlingKey putRepositoryTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deleteRepositoryTaskKey;
 
     public RepositoriesService(
         Settings settings,
@@ -124,7 +138,7 @@ public RepositoriesService(
         this.threadPool = threadPool;
         // Doesn't make sense to maintain repositories on non-master and non-data nodes
         // Nothing happens there anyway
-        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isDataNode(settings) || DiscoveryNode.isClusterManagerNode(settings)) {
             if (isDedicatedVotingOnlyNode(DiscoveryNode.getRolesFromSettings(settings)) == false) {
                 clusterService.addHighPriorityApplier(this);
             }
@@ -135,22 +149,34 @@ public RepositoriesService(
             REPOSITORIES_STATS_ARCHIVE_MAX_ARCHIVED_STATS.get(settings),
             threadPool::relativeTimeInMillis
         );
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        putRepositoryTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.PUT_REPOSITORY_KEY, true);
+        deleteRepositoryTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_REPOSITORY_KEY, true);
     }
 
     /**
-     * Registers new repository in the cluster
+     * Registers new repository or updates an existing repository in the cluster
      * <p>
-     * This method can be only called on the master node. It tries to create a new repository on the master
+     * This method can be only called on the cluster-manager node. It tries to create a new repository on the master
      * and if it was successful it adds new repository to cluster metadata.
      *
      * @param request  register repository request
      * @param listener register repository listener
      */
-    public void registerRepository(final PutRepositoryRequest request, final ActionListener<ClusterStateUpdateResponse> listener) {
+    public void registerOrUpdateRepository(final PutRepositoryRequest request, final ActionListener<ClusterStateUpdateResponse> listener) {
         assert lifecycle.started() : "Trying to register new repository but service is in state [" + lifecycle.state() + "]";
 
-        final RepositoryMetadata newRepositoryMetadata = new RepositoryMetadata(request.name(), request.type(), request.settings());
+        final RepositoryMetadata newRepositoryMetadata = new RepositoryMetadata(
+            request.name(),
+            request.type(),
+            request.settings(),
+            CryptoMetadata.fromRequest(request.cryptoSettings())
+        );
         validate(request.name());
+        validateRepositoryMetadataSettings(clusterService, request.name(), request.settings());
+        if (newRepositoryMetadata.cryptoMetadata() != null) {
+            validate(newRepositoryMetadata.cryptoMetadata().keyProviderName());
+        }
 
         final ActionListener<ClusterStateUpdateResponse> registrationListener;
         if (request.verify()) {
@@ -172,7 +198,7 @@ public void registerRepository(final PutRepositoryRequest request, final ActionL
             registrationListener = listener;
         }
 
-        // Trying to create the new repository on master to make sure it works
+        // Trying to create the new repository on cluster-manager to make sure it works
         try {
             closeRepository(createRepository(newRepositoryMetadata, typesRegistry));
         } catch (Exception e) {
@@ -197,27 +223,58 @@ public ClusterState execute(ClusterState currentState) {
                     if (repositories == null) {
                         logger.info("put repository [{}]", request.name());
                         repositories = new RepositoriesMetadata(
-                            Collections.singletonList(new RepositoryMetadata(request.name(), request.type(), request.settings()))
+                            Collections.singletonList(
+                                new RepositoryMetadata(
+                                    request.name(),
+                                    request.type(),
+                                    request.settings(),
+                                    CryptoMetadata.fromRequest(request.cryptoSettings())
+                                )
+                            )
                         );
                     } else {
                         boolean found = false;
                         List<RepositoryMetadata> repositoriesMetadata = new ArrayList<>(repositories.repositories().size() + 1);
 
                         for (RepositoryMetadata repositoryMetadata : repositories.repositories()) {
-                            if (repositoryMetadata.name().equals(newRepositoryMetadata.name())) {
-                                if (newRepositoryMetadata.equalsIgnoreGenerations(repositoryMetadata)) {
+                            RepositoryMetadata updatedRepositoryMetadata = newRepositoryMetadata;
+                            if (isSystemRepositorySettingPresent(repositoryMetadata.settings())) {
+                                Settings updatedSettings = Settings.builder()
+                                    .put(newRepositoryMetadata.settings())
+                                    .put(SYSTEM_REPOSITORY_SETTING.getKey(), true)
+                                    .build();
+                                updatedRepositoryMetadata = new RepositoryMetadata(
+                                    newRepositoryMetadata.name(),
+                                    newRepositoryMetadata.type(),
+                                    updatedSettings,
+                                    newRepositoryMetadata.cryptoMetadata()
+                                );
+                            }
+                            if (repositoryMetadata.name().equals(updatedRepositoryMetadata.name())) {
+                                if (updatedRepositoryMetadata.equalsIgnoreGenerations(repositoryMetadata)) {
                                     // Previous version is the same as this one no update is needed.
                                     return currentState;
                                 }
+                                ensureCryptoSettingsAreSame(repositoryMetadata, request);
                                 found = true;
-                                repositoriesMetadata.add(newRepositoryMetadata);
+                                if (isSystemRepositorySettingPresent(repositoryMetadata.settings())) {
+                                    ensureValidSystemRepositoryUpdate(updatedRepositoryMetadata, repositoryMetadata);
+                                }
+                                repositoriesMetadata.add(updatedRepositoryMetadata);
                             } else {
                                 repositoriesMetadata.add(repositoryMetadata);
                             }
                         }
                         if (!found) {
                             logger.info("put repository [{}]", request.name());
-                            repositoriesMetadata.add(new RepositoryMetadata(request.name(), request.type(), request.settings()));
+                            repositoriesMetadata.add(
+                                new RepositoryMetadata(
+                                    request.name(),
+                                    request.type(),
+                                    request.settings(),
+                                    CryptoMetadata.fromRequest(request.cryptoSettings())
+                                )
+                            );
                         } else {
                             logger.info("update repository [{}]", request.name());
                         }
@@ -227,6 +284,11 @@ public ClusterState execute(ClusterState currentState) {
                     return ClusterState.builder(currentState).metadata(mdBuilder).build();
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return putRepositoryTaskKey;
+                }
+
                 @Override
                 public void onFailure(String source, Exception e) {
                     logger.warn(() -> new ParameterizedMessage("failed to create repository [{}]", request.name()), e);
@@ -235,8 +297,8 @@ public void onFailure(String source, Exception e) {
 
                 @Override
                 public boolean mustAck(DiscoveryNode discoveryNode) {
-                    // repository is created on both master and data nodes
-                    return discoveryNode.isMasterNode() || discoveryNode.isDataNode();
+                    // repository is created on both cluster-manager and data nodes
+                    return discoveryNode.isClusterManagerNode() || discoveryNode.isDataNode();
                 }
             }
         );
@@ -245,7 +307,7 @@ public boolean mustAck(DiscoveryNode discoveryNode) {
     /**
      * Unregisters repository in the cluster
      * <p>
-     * This method can be only called on the master node. It removes repository information from cluster metadata.
+     * This method can be only called on the cluster-manager node. It removes repository information from cluster metadata.
      *
      * @param request  unregister repository request
      * @param listener unregister repository listener
@@ -270,6 +332,7 @@ public ClusterState execute(ClusterState currentState) {
                         for (RepositoryMetadata repositoryMetadata : repositories.repositories()) {
                             if (Regex.simpleMatch(request.name(), repositoryMetadata.name())) {
                                 ensureRepositoryNotInUse(currentState, repositoryMetadata.name());
+                                ensureNotSystemRepository(repositoryMetadata);
                                 logger.info("delete repository [{}]", repositoryMetadata.name());
                                 changed = true;
                             } else {
@@ -288,10 +351,15 @@ public ClusterState execute(ClusterState currentState) {
                     throw new RepositoryMissingException(request.name());
                 }
 
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return deleteRepositoryTaskKey;
+                }
+
                 @Override
                 public boolean mustAck(DiscoveryNode discoveryNode) {
-                    // repository was created on both master and data nodes
-                    return discoveryNode.isMasterNode() || discoveryNode.isDataNode();
+                    // repository was created on both cluster-manager and data nodes
+                    return discoveryNode.isClusterManagerNode() || discoveryNode.isDataNode();
                 }
             }
         );
@@ -369,7 +437,13 @@ public void applyClusterState(ClusterChangedEvent event) {
             // Check if repositories got changed
             if ((oldMetadata == null && newMetadata == null) || (oldMetadata != null && oldMetadata.equalsIgnoreGenerations(newMetadata))) {
                 for (Repository repo : repositories.values()) {
-                    repo.updateState(state);
+                    // Update State should only be invoked for repository which are already in cluster state. This
+                    // check needs to be added as system repositories can be populated before cluster state has the
+                    // repository metadata.
+                    RepositoriesMetadata stateRepositoriesMetadata = state.metadata().custom(RepositoriesMetadata.TYPE);
+                    if (stateRepositoriesMetadata != null && stateRepositoriesMetadata.repository(repo.getMetadata().name()) != null) {
+                        repo.updateState(state);
+                    }
                 }
                 return;
             }
@@ -400,24 +474,49 @@ public void applyClusterState(ClusterChangedEvent event) {
                         if (previousMetadata.type().equals(repositoryMetadata.type()) == false
                             || previousMetadata.settings().equals(repositoryMetadata.settings()) == false) {
                             // Previous version is different from the version in settings
-                            logger.debug("updating repository [{}]", repositoryMetadata.name());
-                            closeRepository(repository);
-                            archiveRepositoryStats(repository, state.version());
-                            repository = null;
-                            try {
-                                repository = createRepository(repositoryMetadata, typesRegistry);
-                            } catch (RepositoryException ex) {
-                                // TODO: this catch is bogus, it means the old repo is already closed,
-                                // but we have nothing to replace it
-                                logger.warn(
-                                    () -> new ParameterizedMessage("failed to change repository [{}]", repositoryMetadata.name()),
-                                    ex
+                            if (repository.isSystemRepository() && repository.isReloadable()) {
+                                logger.debug(
+                                    "updating repository [{}] in-place to use new metadata [{}]",
+                                    repositoryMetadata.name(),
+                                    repositoryMetadata
                                 );
+                                repository.validateMetadata(repositoryMetadata);
+                                repository.reload(repositoryMetadata);
+                            } else {
+                                logger.debug("updating repository [{}]", repositoryMetadata.name());
+                                closeRepository(repository);
+                                archiveRepositoryStats(repository, state.version());
+                                repository = null;
+                                try {
+                                    repository = createRepository(repositoryMetadata, typesRegistry);
+                                } catch (RepositoryException ex) {
+                                    // TODO: this catch is bogus, it means the old repo is already closed,
+                                    // but we have nothing to replace it
+                                    logger.warn(
+                                        () -> new ParameterizedMessage("failed to change repository [{}]", repositoryMetadata.name()),
+                                        ex
+                                    );
+                                }
                             }
                         }
                     } else {
                         try {
-                            repository = createRepository(repositoryMetadata, typesRegistry);
+                            // System repositories are already created and verified and hence during cluster state
+                            // update we should avoid creating it again. Once the cluster state is update with the
+                            // repository metadata the repository metadata update will land in the above if block.
+                            if (repositories.containsKey(repositoryMetadata.name()) == false) {
+                                repository = createRepository(repositoryMetadata, typesRegistry);
+                            } else {
+                                // Validate the repository metadata which was created during bootstrap is same as the
+                                // one present in incoming cluster state.
+                                repository = repositories.get(repositoryMetadata.name());
+                                if (repositoryMetadata.equalsIgnoreGenerations(repository.getMetadata()) == false) {
+                                    throw new RepositoryException(
+                                        repositoryMetadata.name(),
+                                        "repository was already " + "registered with different metadata during bootstrap than cluster state"
+                                    );
+                                }
+                            }
                         } catch (RepositoryException ex) {
                             logger.warn(() -> new ParameterizedMessage("failed to create repository [{}]", repositoryMetadata.name()), ex);
                         }
@@ -457,7 +556,7 @@ public void getRepositoryData(final String repositoryName, final ActionListener<
     /**
      * Returns registered repository
      * <p>
-     * This method is called only on the master node
+     * This method is called only on the cluster-manager node
      *
      * @param repositoryName repository name
      * @return registered repository
@@ -536,7 +635,7 @@ public void unregisterInternalRepository(String name) {
     }
 
     /** Closes the given repository. */
-    private void closeRepository(Repository repository) {
+    public void closeRepository(Repository repository) {
         logger.debug("closing repository [{}][{}]", repository.getMetadata().type(), repository.getMetadata().name());
         repository.close();
     }
@@ -550,6 +649,13 @@ private void archiveRepositoryStats(Repository repository, long clusterStateVers
         }
     }
 
+    /**
+     * Creates repository holder. This method starts the non-internal repository
+     */
+    public Repository createRepository(RepositoryMetadata repositoryMetadata) {
+        return this.createRepository(repositoryMetadata, typesRegistry);
+    }
+
     /**
      * Creates repository holder. This method starts the repository
      */
@@ -574,15 +680,44 @@ private Repository createRepository(RepositoryMetadata repositoryMetadata, Map<S
         }
     }
 
-    private static void validate(final String repositoryName) {
-        if (Strings.hasLength(repositoryName) == false) {
-            throw new RepositoryException(repositoryName, "cannot be empty");
+    public static void validate(final String identifier) {
+        if (org.opensearch.core.common.Strings.hasLength(identifier) == false) {
+            throw new RepositoryException(identifier, "cannot be empty");
+        }
+        if (identifier.contains("#")) {
+            throw new RepositoryException(identifier, "must not contain '#'");
         }
-        if (repositoryName.contains("#")) {
-            throw new RepositoryException(repositoryName, "must not contain '#'");
+        if (Strings.validFileName(identifier) == false) {
+            throw new RepositoryException(identifier, "must not contain the following characters " + Strings.INVALID_FILENAME_CHARS);
+        }
+    }
+
+    public static void validateRepositoryMetadataSettings(
+        ClusterService clusterService,
+        final String repositoryName,
+        final Settings repositoryMetadataSettings
+    ) {
+        // We can add more validations here for repository settings in the future.
+        Version minVersionInCluster = clusterService.state().getNodes().getMinNodeVersion();
+        if (REMOTE_STORE_INDEX_SHALLOW_COPY.get(repositoryMetadataSettings) && !minVersionInCluster.onOrAfter(Version.V_2_9_0)) {
+            throw new RepositoryException(
+                repositoryName,
+                "setting "
+                    + REMOTE_STORE_INDEX_SHALLOW_COPY.getKey()
+                    + " cannot be enabled as some of the nodes in cluster are on version older than "
+                    + Version.V_2_9_0
+                    + ". Minimum node version in cluster is: "
+                    + minVersionInCluster
+            );
         }
-        if (Strings.validFileName(repositoryName) == false) {
-            throw new RepositoryException(repositoryName, "must not contain the following characters " + Strings.INVALID_FILENAME_CHARS);
+        // Validation to not allow users to create system repository via put repository call.
+        if (isSystemRepositorySettingPresent(repositoryMetadataSettings)) {
+            throw new RepositoryException(
+                repositoryName,
+                "setting "
+                    + SYSTEM_REPOSITORY_SETTING.getKey()
+                    + " cannot provide system repository setting; this setting is managed by OpenSearch"
+            );
         }
     }
 
@@ -592,6 +727,23 @@ private static void ensureRepositoryNotInUse(ClusterState clusterState, String r
         }
     }
 
+    private static void ensureCryptoSettingsAreSame(RepositoryMetadata repositoryMetadata, PutRepositoryRequest request) {
+        if (repositoryMetadata.cryptoMetadata() == null && request.cryptoSettings() == null) {
+            return;
+        }
+        if (repositoryMetadata.cryptoMetadata() == null || request.cryptoSettings() == null) {
+            throw new IllegalArgumentException("Crypto settings changes found in the repository update request. This is not allowed");
+        }
+
+        CryptoMetadata cryptoMetadata = repositoryMetadata.cryptoMetadata();
+        CryptoSettings cryptoSettings = request.cryptoSettings();
+        if (!cryptoMetadata.keyProviderName().equals(cryptoSettings.getKeyProviderName())
+            || !cryptoMetadata.keyProviderType().equals(cryptoSettings.getKeyProviderType())
+            || !cryptoMetadata.settings().toString().equals(cryptoSettings.getSettings().toString())) {
+            throw new IllegalArgumentException("Changes in crypto settings found in the repository update request. This is not allowed");
+        }
+    }
+
     /**
      * Checks if a repository is currently in use by one of the snapshots
      *
@@ -630,6 +782,76 @@ private static boolean isRepositoryInUse(ClusterState clusterState, String repos
         return false;
     }
 
+    /**
+     * This method will be used to update the repositories map.
+     */
+    public void updateRepositoriesMap(Map<String, Repository> repos) {
+        if (repositories.isEmpty()) {
+            repositories = repos;
+        } else {
+            throw new IllegalArgumentException("can't overwrite as repositories are already present");
+        }
+    }
+
+    private static void ensureNotSystemRepository(RepositoryMetadata repositoryMetadata) {
+        if (isSystemRepositorySettingPresent(repositoryMetadata.settings())) {
+            throw new RepositoryException(repositoryMetadata.name(), "cannot delete a system repository");
+        }
+    }
+
+    private static boolean isSystemRepositorySettingPresent(Settings repositoryMetadataSettings) {
+        return SYSTEM_REPOSITORY_SETTING.get(repositoryMetadataSettings);
+    }
+
+    private static boolean isValueEqual(String key, String newValue, String currentValue) {
+        if (newValue == null && currentValue == null) {
+            return true;
+        }
+        if (newValue == null) {
+            throw new IllegalArgumentException("[" + key + "] cannot be empty, " + "current value [" + currentValue + "]");
+        }
+        if (newValue.equals(currentValue) == false) {
+            throw new IllegalArgumentException(
+                "trying to modify an unmodifiable attribute "
+                    + key
+                    + " of system repository from "
+                    + "current value ["
+                    + currentValue
+                    + "] to new value ["
+                    + newValue
+                    + "]"
+            );
+        }
+        return true;
+    }
+
+    public void ensureValidSystemRepositoryUpdate(RepositoryMetadata newRepositoryMetadata, RepositoryMetadata currentRepositoryMetadata) {
+        if (isSystemRepositorySettingPresent(currentRepositoryMetadata.settings())) {
+            try {
+                isValueEqual("type", newRepositoryMetadata.type(), currentRepositoryMetadata.type());
+
+                Repository repository = repositories.get(currentRepositoryMetadata.name());
+                Settings newRepositoryMetadataSettings = newRepositoryMetadata.settings();
+                Settings currentRepositoryMetadataSettings = currentRepositoryMetadata.settings();
+
+                List<String> restrictedSettings = repository.getRestrictedSystemRepositorySettings()
+                    .stream()
+                    .map(setting -> setting.getKey())
+                    .collect(Collectors.toList());
+
+                for (String restrictedSettingKey : restrictedSettings) {
+                    isValueEqual(
+                        restrictedSettingKey,
+                        newRepositoryMetadataSettings.get(restrictedSettingKey),
+                        currentRepositoryMetadataSettings.get(restrictedSettingKey)
+                    );
+                }
+            } catch (IllegalArgumentException e) {
+                throw new RepositoryException(currentRepositoryMetadata.name(), e.getMessage());
+            }
+        }
+    }
+
     @Override
     protected void doStart() {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoriesStatsArchive.java b/server/src/main/java/org/opensearch/repositories/RepositoriesStatsArchive.java
index f5c600b5ff444..b8f100706f81e 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoriesStatsArchive.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoriesStatsArchive.java
@@ -44,6 +44,11 @@
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
 
+/**
+ * Archive of repository stats
+ *
+ * @opensearch.internal
+ */
 public final class RepositoriesStatsArchive {
     private static final Logger logger = LogManager.getLogger(RepositoriesStatsArchive.class);
 
diff --git a/server/src/main/java/org/opensearch/repositories/Repository.java b/server/src/main/java/org/opensearch/repositories/Repository.java
index c8907393824c2..6781b72d4b8d7 100644
--- a/server/src/main/java/org/opensearch/repositories/Repository.java
+++ b/server/src/main/java/org/opensearch/repositories/Repository.java
@@ -33,7 +33,6 @@
 
 import org.apache.lucene.index.IndexCommit;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.SnapshotsInProgress;
@@ -42,17 +41,22 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.component.LifecycleComponent;
+import org.opensearch.common.lifecycle.LifecycleComponent;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
@@ -68,8 +72,10 @@
  * <ul>
  * <li>Data nodes call {@link Repository#snapshotShard}
  * for each shard</li>
- * <li>When all shard calls return master calls {@link #finalizeSnapshot} with possible list of failures</li>
+ * <li>When all shard calls return cluster-manager calls {@link #finalizeSnapshot} with possible list of failures</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public interface Repository extends LifecycleComponent {
 
@@ -134,7 +140,7 @@ default Repository create(RepositoryMetadata metadata, Function<String, Reposito
      * @param indices    list of indices to be snapshotted
      * @param metadata   cluster metadata
      *
-     * @deprecated this method is only used when taking snapshots in a mixed version cluster where a master node older than
+     * @deprecated this method is only used when taking snapshots in a mixed version cluster where a cluster-manager node older than
      *             {@link org.opensearch.snapshots.SnapshotsService#NO_REPO_INITIALIZE_VERSION} is present.
      */
     @Deprecated
@@ -143,7 +149,7 @@ default Repository create(RepositoryMetadata metadata, Function<String, Reposito
     /**
      * Finalizes snapshotting process
      * <p>
-     * This method is called on master after all shards are snapshotted.
+     * This method is called on cluster-manager after all shards are snapshotted.
      *
      * @param shardGenerations      updated shard generations
      * @param repositoryStateId     the unique id identifying the state of the repository when the snapshot began
@@ -179,6 +185,25 @@ void deleteSnapshots(
         ActionListener<RepositoryData> listener
     );
 
+    /**
+     * Deletes snapshots and releases respective lock files from remote store repository.
+     *
+     * @param snapshotIds                   snapshot ids
+     * @param repositoryStateId             the unique id identifying the state of the repository when the snapshot deletion began
+     * @param repositoryMetaVersion         version of the updated repository metadata to write
+     * @param remoteStoreLockManagerFactory RemoteStoreLockManagerFactory to be used for cleaning up remote store lock files
+     * @param listener                      completion listener
+     */
+    default void deleteSnapshotsAndReleaseLockFiles(
+        Collection<SnapshotId> snapshotIds,
+        long repositoryStateId,
+        Version repositoryMetaVersion,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<RepositoryData> listener
+    ) {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Returns snapshot throttle time in nanoseconds
      */
@@ -189,6 +214,16 @@ void deleteSnapshots(
      */
     long getRestoreThrottleTimeInNanos();
 
+    /**
+     * Returns restore throttle time in nanoseconds
+     */
+    long getRemoteUploadThrottleTimeInNanos();
+
+    /**
+     * Returns restore throttle time in nanoseconds
+     */
+    long getRemoteDownloadThrottleTimeInNanos();
+
     /**
      * Returns stats on the repository usage
      */
@@ -197,7 +232,7 @@ default RepositoryStats stats() {
     }
 
     /**
-     * Verifies repository on the master node and returns the verification token.
+     * Verifies repository on the cluster-manager node and returns the verification token.
      * <p>
      * If the verification token is not null, it's passed to all data nodes for verification. If it's null - no
      * additional verification is required
@@ -228,6 +263,13 @@ default RepositoryStats stats() {
      */
     boolean isReadOnly();
 
+    /**
+     * Returns true if the repository is managed by the system directly and doesn't allow managing the lifetime of the
+     * repository through external APIs
+     * @return true if the repository is system managed
+     */
+    boolean isSystemRepository();
+
     /**
      * Creates a snapshot of the shard based on the index commit point.
      * <p>
@@ -236,18 +278,18 @@ default RepositoryStats stats() {
      * <p>
      * As snapshot process progresses, implementation of this method should update {@link IndexShardSnapshotStatus} object and check
      * {@link IndexShardSnapshotStatus#isAborted()} to see if the snapshot process should be aborted.
-     * @param store                 store to be snapshotted
-     * @param mapperService         the shards mapper service
-     * @param snapshotId            snapshot id
-     * @param indexId               id for the index being snapshotted
-     * @param snapshotIndexCommit   commit point
-     * @param shardStateIdentifier  a unique identifier of the state of the shard that is stored with the shard's snapshot and used
-     *                              to detect if the shard has changed between snapshots. If {@code null} is passed as the identifier
-     *                              snapshotting will be done by inspecting the physical files referenced by {@code snapshotIndexCommit}
-     * @param snapshotStatus        snapshot status
-     * @param repositoryMetaVersion version of the updated repository metadata to write
-     * @param userMetadata          user metadata of the snapshot found in {@link SnapshotsInProgress.Entry#userMetadata()}
-     * @param listener              listener invoked on completion
+     * @param store                    store to be snapshotted
+     * @param mapperService            the shards mapper service
+     * @param snapshotId               snapshot id
+     * @param indexId                  id for the index being snapshotted
+     * @param snapshotIndexCommit      commit point
+     * @param shardStateIdentifier     a unique identifier of the state of the shard that is stored with the shard's snapshot and used
+     *                                 to detect if the shard has changed between snapshots. If {@code null} is passed as the identifier
+     *                                 snapshotting will be done by inspecting the physical files referenced by {@code snapshotIndexCommit}
+     * @param snapshotStatus           snapshot status
+     * @param repositoryMetaVersion    version of the updated repository metadata to write
+     * @param userMetadata             user metadata of the snapshot found in {@link SnapshotsInProgress.Entry#userMetadata()}
+     * @param listener                 listener invoked on completion
      */
     void snapshotShard(
         Store store,
@@ -262,6 +304,40 @@ void snapshotShard(
         ActionListener<String> listener
     );
 
+    /**
+     * Adds a reference of remote store data for a index commit point.
+     * <p>
+     * The index commit point can be obtained by using {@link org.opensearch.index.engine.Engine#acquireLastIndexCommit} method.
+     * Repository implementations shouldn't release the snapshot index commit point. It is done by the method caller.
+     * <p>
+     * As snapshot process progresses, implementation of this method should update {@link IndexShardSnapshotStatus} object and check
+     * {@link IndexShardSnapshotStatus#isAborted()} to see if the snapshot process should be aborted.
+     * @param store                    store to be snapshotted
+     * @param snapshotId               snapshot id
+     * @param indexId                  id for the index being snapshotted
+     * @param snapshotIndexCommit      commit point
+     * @param shardStateIdentifier     a unique identifier of the state of the shard that is stored with the shard's snapshot and used
+     *                                 to detect if the shard has changed between snapshots. If {@code null} is passed as the identifier
+     *                                 snapshotting will be done by inspecting the physical files referenced by {@code snapshotIndexCommit}
+     * @param snapshotStatus           snapshot status
+     * @param primaryTerm              current Primary Term
+     * @param startTime                start time of the snapshot commit, this will be used as the start time for snapshot.
+     * @param listener                 listener invoked on completion
+     */
+    default void snapshotRemoteStoreIndexShard(
+        Store store,
+        SnapshotId snapshotId,
+        IndexId indexId,
+        IndexCommit snapshotIndexCommit,
+        @Nullable String shardStateIdentifier,
+        IndexShardSnapshotStatus snapshotStatus,
+        long primaryTerm,
+        long startTime,
+        ActionListener<String> listener
+    ) {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Restores snapshot of the shard.
      * <p>
@@ -282,6 +358,30 @@ void restoreShard(
         ActionListener<Void> listener
     );
 
+    /**
+     * Returns the list of restricted system repository settings that cannot be mutated post repository creation.
+     * @return list of settings
+     */
+    default List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        return Collections.emptyList();
+    }
+
+    /**
+     * Returns Snapshot Shard Metadata for remote store interop enabled snapshot.
+     * <p>
+     * The index can be renamed on restore, hence different {@code shardId} and {@code snapshotShardId} are supplied.
+     * @param snapshotId      snapshot id
+     * @param indexId         id of the index in the repository from which the restore is occurring
+     * @param snapshotShardId shard id (in the snapshot)
+     */
+    default RemoteStoreShardShallowCopySnapshot getRemoteStoreShallowCopyShardMetadata(
+        SnapshotId snapshotId,
+        IndexId indexId,
+        ShardId snapshotShardId
+    ) {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Retrieve shard snapshot status for the stored snapshot
      *
@@ -336,6 +436,27 @@ void cloneShardSnapshot(
         ActionListener<String> listener
     );
 
+    /**
+     * Clones a remote store index shard snapshot.
+     *
+     * @param source                        source snapshot
+     * @param target                        target snapshot
+     * @param shardId                       shard id
+     * @param shardGeneration               shard generation in repo
+     * @param remoteStoreLockManagerFactory remoteStoreLockManagerFactory for cloning metadata lock file
+     * @param listener                      listener to complete with new shard generation once clone has completed
+     */
+    default void cloneRemoteStoreIndexShardSnapshot(
+        SnapshotId source,
+        SnapshotId target,
+        RepositoryShardId shardId,
+        @Nullable String shardGeneration,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<String> listener
+    ) {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Hook that allows a repository to filter the user supplied snapshot metadata in {@link SnapshotsInProgress.Entry#userMetadata()}
      * during snapshot initialization.
@@ -343,4 +464,22 @@ void cloneShardSnapshot(
     default Map<String, Object> adaptUserMetadata(Map<String, Object> userMetadata) {
         return userMetadata;
     }
+
+    /**
+     * Checks if the repository can be reloaded inplace or not
+     * @return true if the repository can be reloaded inplace, false otherwise
+     */
+    default boolean isReloadable() {
+        return false;
+    }
+
+    /**
+     * Reload the repository inplace
+     */
+    default void reload(RepositoryMetadata repositoryMetadata) {}
+
+    /**
+     * Validate the repository metadata
+     */
+    default void validateMetadata(RepositoryMetadata repositoryMetadata) {}
 }
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryCleanupResult.java b/server/src/main/java/org/opensearch/repositories/RepositoryCleanupResult.java
index 7851274a48fbe..f09aae195f0e5 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryCleanupResult.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryCleanupResult.java
@@ -31,18 +31,24 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.DeleteResult;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Result of a repository cleanup action
+ *
+ * @opensearch.internal
+ */
 public final class RepositoryCleanupResult implements Writeable, ToXContentObject {
 
     public static final ObjectParser<RepositoryCleanupResult, Void> PARSER = new ObjectParser<>(
@@ -99,6 +105,6 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryData.java b/server/src/main/java/org/opensearch/repositories/RepositoryData.java
index 7857df512cd75..4e527da4b4717 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryData.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryData.java
@@ -37,9 +37,9 @@
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotState;
 import org.opensearch.snapshots.SnapshotsService;
@@ -60,6 +60,8 @@
 /**
  * A class that represents the data in a repository, as captured in the
  * repository's index blob.
+ *
+ * @opensearch.internal
  */
 public final class RepositoryData {
 
@@ -598,9 +600,11 @@ public XContentBuilder snapshotsToXContent(final XContentBuilder builder, final
         }
         builder.endObject();
         if (shouldWriteIndexGens) {
-            builder.field(MIN_VERSION, SnapshotsService.INDEX_GEN_IN_REPO_DATA_VERSION.toString());
+            if (repoMetaVersion.before(Version.V_2_4_0)) {
+                builder.field(MIN_VERSION, SnapshotsService.INDEX_GEN_IN_REPO_DATA_VERSION.toString());
+            }
             builder.field(INDEX_METADATA_IDENTIFIERS, indexMetaDataGenerations.identifiers);
-        } else if (shouldWriteShardGens) {
+        } else if (shouldWriteShardGens && repoMetaVersion.before(Version.V_2_4_0)) {
             // Add min version field to make it impossible for older OpenSearch versions to deserialize this object
             builder.field(MIN_VERSION, SnapshotsService.SHARD_GEN_IN_REPO_DATA_VERSION.toString());
         }
@@ -643,10 +647,14 @@ public static RepositoryData snapshotsFromXContent(XContentParser parser, long g
                     XContentParserUtils.ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
                     indexMetaIdentifiers = parser.mapStrings();
                     break;
-                case MIN_VERSION:
-                    XContentParserUtils.ensureExpectedToken(XContentParser.Token.VALUE_STRING, parser.nextToken(), parser);
-                    final Version version = Version.fromString(parser.text());
-                    assert SnapshotsService.useShardGenerations(version);
+                case MIN_VERSION: // todo: remove in 3.0
+                    if (Version.CURRENT.major < 3) {
+                        XContentParserUtils.ensureExpectedToken(XContentParser.Token.VALUE_STRING, parser.nextToken(), parser);
+                        final Version version = Version.fromString(parser.text());
+                        assert SnapshotsService.useShardGenerations(version);
+                    } else {
+                        throw new OpenSearchParseException("Field [{}] was removed in version 2.4.0 and no longer supported.", MIN_VERSION);
+                    }
                     break;
                 default:
                     XContentParserUtils.throwUnknownField(field, parser.getTokenLocation());
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryException.java b/server/src/main/java/org/opensearch/repositories/RepositoryException.java
index 8196fa24f2a92..a3e8cc9c3744e 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryException.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryException.java
@@ -33,13 +33,15 @@
 package org.opensearch.repositories;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Generic repository exception
+ *
+ * @opensearch.internal
  */
 public class RepositoryException extends OpenSearchException {
     private final String repository;
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryInfo.java b/server/src/main/java/org/opensearch/repositories/RepositoryInfo.java
index 5266cfa28bd0e..8aa86fc46d591 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryInfo.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryInfo.java
@@ -33,17 +33,23 @@
 package org.opensearch.repositories;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Information about a repository
+ *
+ * @opensearch.internal
+ */
 public final class RepositoryInfo implements Writeable, ToXContentFragment {
     public final String ephemeralId;
     public final String name;
@@ -138,6 +144,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryMissingException.java b/server/src/main/java/org/opensearch/repositories/RepositoryMissingException.java
index 5a0b59e50e62f..c39e03e5bb656 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryMissingException.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryMissingException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Repository missing exception
+ *
+ * @opensearch.internal
  */
 public class RepositoryMissingException extends RepositoryException {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryOperation.java b/server/src/main/java/org/opensearch/repositories/RepositoryOperation.java
index 5e11d3e2f400e..ec8dcd5ca91a3 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryOperation.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryOperation.java
@@ -33,6 +33,8 @@
 
 /**
  * Coordinates of an operation that modifies a repository, assuming that repository at a specific generation.
+ *
+ * @opensearch.internal
  */
 public interface RepositoryOperation {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryShardId.java b/server/src/main/java/org/opensearch/repositories/RepositoryShardId.java
index cd4e180215db0..4799f36156a73 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryShardId.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryShardId.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Represents a shard snapshot in a repository.
+ *
+ * @opensearch.internal
  */
 public final class RepositoryShardId implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryStats.java b/server/src/main/java/org/opensearch/repositories/RepositoryStats.java
index c832b86eb69a4..efd5d6f8560b6 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryStats.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryStats.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Stats about a repository
+ *
+ * @opensearch.internal
+ */
 public class RepositoryStats implements Writeable {
 
     public static final RepositoryStats EMPTY_STATS = new RepositoryStats(Collections.emptyMap());
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryStatsSnapshot.java b/server/src/main/java/org/opensearch/repositories/RepositoryStatsSnapshot.java
index c7824e29bc953..2b061cd2c2cc9 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryStatsSnapshot.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryStatsSnapshot.java
@@ -32,16 +32,22 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Stats snapshot about a repository
+ *
+ * @opensearch.internal
+ */
 public final class RepositoryStatsSnapshot implements Writeable, ToXContentObject {
     public static final long UNKNOWN_CLUSTER_VERSION = -1;
     private final RepositoryInfo repositoryInfo;
@@ -119,6 +125,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/repositories/RepositoryVerificationException.java b/server/src/main/java/org/opensearch/repositories/RepositoryVerificationException.java
index 949c1b7e25ff9..485635b3b618c 100644
--- a/server/src/main/java/org/opensearch/repositories/RepositoryVerificationException.java
+++ b/server/src/main/java/org/opensearch/repositories/RepositoryVerificationException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.repositories;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Repository verification exception
+ *
+ * @opensearch.internal
  */
 public class RepositoryVerificationException extends RepositoryException {
 
diff --git a/server/src/main/java/org/opensearch/repositories/ShardGenerations.java b/server/src/main/java/org/opensearch/repositories/ShardGenerations.java
index 28cca3fe26646..27eac4dfdd8c1 100644
--- a/server/src/main/java/org/opensearch/repositories/ShardGenerations.java
+++ b/server/src/main/java/org/opensearch/repositories/ShardGenerations.java
@@ -47,6 +47,11 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+/**
+ * Generations of shards for snapshots
+ *
+ * @opensearch.internal
+ */
 public final class ShardGenerations {
 
     public static final ShardGenerations EMPTY = new ShardGenerations(Collections.emptyMap());
@@ -190,6 +195,11 @@ public static Builder builder() {
         return new Builder();
     }
 
+    /**
+     * Builder for the shard generations.
+     *
+     * @opensearch.internal
+     */
     public static final class Builder {
 
         private final Map<IndexId, Map<Integer, String>> generations = new HashMap<>();
diff --git a/server/src/main/java/org/opensearch/repositories/VerificationFailure.java b/server/src/main/java/org/opensearch/repositories/VerificationFailure.java
index d285f3418eea5..51f0caed04903 100644
--- a/server/src/main/java/org/opensearch/repositories/VerificationFailure.java
+++ b/server/src/main/java/org/opensearch/repositories/VerificationFailure.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.repositories;
 
+/**
+ * Exception thrown when a repository fails verification
+ *
+ * @opensearch.internal
+ */
 public class VerificationFailure {
 
     private String nodeId;
diff --git a/server/src/main/java/org/opensearch/repositories/VerifyNodeRepositoryAction.java b/server/src/main/java/org/opensearch/repositories/VerifyNodeRepositoryAction.java
index 70bc4b9590385..96f9081e23c77 100644
--- a/server/src/main/java/org/opensearch/repositories/VerifyNodeRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/repositories/VerifyNodeRepositoryAction.java
@@ -32,17 +32,16 @@
 
 package org.opensearch.repositories;
 
-import com.carrotsearch.hppc.ObjectContainer;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.EmptyTransportResponseHandler;
@@ -50,15 +49,20 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicInteger;
 
+/**
+ * Action to verify a node repository
+ *
+ * @opensearch.internal
+ */
 public class VerifyNodeRepositoryAction {
 
     private static final Logger logger = LogManager.getLogger(VerifyNodeRepositoryAction.class);
@@ -91,10 +95,9 @@ public void verify(String repository, String verificationToken, final ActionList
         final DiscoveryNodes discoNodes = clusterService.state().nodes();
         final DiscoveryNode localNode = discoNodes.getLocalNode();
 
-        final ObjectContainer<DiscoveryNode> masterAndDataNodes = discoNodes.getMasterAndDataNodes().values();
+        final Collection<DiscoveryNode> masterAndDataNodes = discoNodes.getClusterManagerAndDataNodes().values();
         final List<DiscoveryNode> nodes = new ArrayList<>();
-        for (ObjectCursor<DiscoveryNode> cursor : masterAndDataNodes) {
-            DiscoveryNode node = cursor.value;
+        for (final DiscoveryNode node : masterAndDataNodes) {
             if (RepositoriesService.isDedicatedVotingOnlyNode(node.getRoles()) == false) {
                 nodes.add(node);
             }
@@ -156,6 +159,11 @@ private void doVerify(String repositoryName, String verificationToken, Discovery
         repository.verify(verificationToken, localNode);
     }
 
+    /**
+     * Request to verify a node repository.
+     *
+     * @opensearch.internal
+     */
     public static class VerifyNodeRepositoryRequest extends TransportRequest {
 
         private String repository;
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java b/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
index 7d6cdef76198f..20d9455cdf9e9 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
@@ -45,10 +45,8 @@
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.RateLimiter;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.GroupedActionListener;
@@ -63,52 +61,68 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Numbers;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.blobstore.DeleteResult;
+import org.opensearch.common.blobstore.EncryptedBlobStore;
 import org.opensearch.common.blobstore.fs.FsBlobContainer;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeInputStream;
+import org.opensearch.common.blobstore.transfer.stream.RateLimitingOffsetRangeInputStream;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.compress.CompressorFactory;
-import org.opensearch.common.compress.NotXContentException;
+import org.opensearch.common.compress.DeflateCompressor;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.store.InputStreamIndexInput;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.compress.NotXContentException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException;
+import org.opensearch.core.util.BytesRefUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardRestoreFailedException;
-import org.opensearch.index.snapshots.IndexShardSnapshotFailedException;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
 import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshots;
+import org.opensearch.index.snapshots.blobstore.IndexShardSnapshot;
 import org.opensearch.index.snapshots.blobstore.RateLimitingInputStream;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
 import org.opensearch.index.snapshots.blobstore.SlicedInputStream;
 import org.opensearch.index.snapshots.blobstore.SnapshotFiles;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.lockmanager.FileLockInfo;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManager;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.repositories.IndexId;
@@ -136,9 +150,11 @@
 import java.io.InputStream;
 import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
@@ -147,6 +163,7 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Consumer;
@@ -166,6 +183,8 @@
  * </p>
  * For in depth documentation on how exactly implementations of this class interact with the snapshot functionality please refer to the
  * documentation of the package {@link org.opensearch.repositories.blobstore}.
+ *
+ * @opensearch.internal
  */
 public abstract class BlobStoreRepository extends AbstractLifecycleComponent implements Repository {
     private static final Logger logger = LogManager.getLogger(BlobStoreRepository.class);
@@ -176,6 +195,8 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     public static final String SNAPSHOT_PREFIX = "snap-";
 
+    public static final String SHALLOW_SNAPSHOT_PREFIX = "shallow-snap-";
+
     public static final String INDEX_FILE_PREFIX = "index-";
 
     public static final String INDEX_LATEST_BLOB = "index.latest";
@@ -188,6 +209,8 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     public static final String SNAPSHOT_NAME_FORMAT = SNAPSHOT_PREFIX + "%s.dat";
 
+    public static final String SHALLOW_SNAPSHOT_NAME_FORMAT = SHALLOW_SNAPSHOT_PREFIX + "%s.dat";
+
     private static final String SNAPSHOT_INDEX_PREFIX = "index-";
 
     private static final String SNAPSHOT_INDEX_NAME_FORMAT = SNAPSHOT_INDEX_PREFIX + "%s";
@@ -200,7 +223,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
      * {@link BlobStoreIndexShardSnapshots}. This is the case for files for which {@link StoreFileMetadata#hashEqualsContents()} is
      * {@code true}.
      */
-    private static final String VIRTUAL_DATA_BLOB_PREFIX = "v__";
+    public static final String VIRTUAL_DATA_BLOB_PREFIX = "v__";
 
     /**
      * When set to {@code true}, {@link #bestEffortConsistency} will be set to {@code true} and concurrent modifications of the repository
@@ -233,26 +256,72 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         Setting.Property.NodeScope
     );
 
+    public static final Setting<Boolean> REMOTE_STORE_INDEX_SHALLOW_COPY = Setting.boolSetting("remote_store_index_shallow_copy", false);
+
+    /**
+     * Setting to set batch size of stale snapshot shard blobs that will be deleted by snapshot workers as part of snapshot deletion.
+     * For optimal performance the value of the setting should be equal to or close to repository's max # of keys that can be deleted in single operation
+     * Most cloud storage support upto 1000 key(s) deletion in single operation, thus keeping default value to be 1000.
+     */
+    public static final Setting<Integer> MAX_SNAPSHOT_SHARD_BLOB_DELETE_BATCH_SIZE = Setting.intSetting(
+        "max_snapshot_shard_blob_delete_batch_size",
+        1000, // the default maximum batch size of stale snapshot shard blobs deletion
+        Setting.Property.NodeScope
+    );
+
+    public static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", false, Setting.Property.NodeScope);
+
+    public static final Setting<Compressor> COMPRESSION_TYPE_SETTING = new Setting<>(
+        "compression_type",
+        DeflateCompressor.NAME.toLowerCase(Locale.ROOT),
+        s -> CompressorRegistry.getCompressor(s.toUpperCase(Locale.ROOT)),
+        Setting.Property.NodeScope
+    );
+
     /**
      * Setting to disable writing the {@code index.latest} blob which enables the contents of this repository to be used with a
      * url-repository.
      */
     public static final Setting<Boolean> SUPPORT_URL_REPO = Setting.boolSetting("support_url_repo", true, Setting.Property.NodeScope);
 
-    protected final boolean supportURLRepo;
+    /***
+     * Setting to set repository as readonly
+     */
+    public static final Setting<Boolean> READONLY_SETTING = Setting.boolSetting("readonly", false, Setting.Property.NodeScope);
+
+    /***
+     * Setting to set repository as system repository
+     */
+    public static final Setting<Boolean> SYSTEM_REPOSITORY_SETTING = Setting.boolSetting(
+        "system_repository",
+        false,
+        Setting.Property.NodeScope
+    );
+
+    protected volatile boolean supportURLRepo;
+
+    private volatile int maxShardBlobDeleteBatch;
+
+    private volatile Compressor compressor;
 
-    private final boolean compress;
+    private volatile boolean cacheRepositoryData;
 
-    private final boolean cacheRepositoryData;
+    private volatile RateLimiter snapshotRateLimiter;
 
-    private final RateLimiter snapshotRateLimiter;
+    private volatile RateLimiter restoreRateLimiter;
 
-    private final RateLimiter restoreRateLimiter;
+    private volatile RateLimiter remoteUploadRateLimiter;
+
+    private volatile RateLimiter remoteDownloadRateLimiter;
 
     private final CounterMetric snapshotRateLimitingTimeInNanos = new CounterMetric();
 
     private final CounterMetric restoreRateLimitingTimeInNanos = new CounterMetric();
 
+    private final CounterMetric remoteDownloadRateLimitingTimeInNanos = new CounterMetric();
+
+    private final CounterMetric remoteUploadRateLimitingTimeInNanos = new CounterMetric();
+
     public static final ChecksumBlobStoreFormat<Metadata> GLOBAL_METADATA_FORMAT = new ChecksumBlobStoreFormat<>(
         "metadata",
         METADATA_NAME_FORMAT,
@@ -279,13 +348,18 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         BlobStoreIndexShardSnapshot::fromXContent
     );
 
+    public static final ChecksumBlobStoreFormat<RemoteStoreShardShallowCopySnapshot> REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT =
+        new ChecksumBlobStoreFormat<>(SNAPSHOT_CODEC, SHALLOW_SNAPSHOT_NAME_FORMAT, RemoteStoreShardShallowCopySnapshot::fromXContent);
+
     public static final ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshots> INDEX_SHARD_SNAPSHOTS_FORMAT = new ChecksumBlobStoreFormat<>(
         "snapshots",
         SNAPSHOT_INDEX_NAME_FORMAT,
         BlobStoreIndexShardSnapshots::fromXContent
     );
 
-    private final boolean readOnly;
+    private volatile boolean readOnly;
+
+    private final boolean isSystemRepository;
 
     private final Object lock = new Object();
 
@@ -293,7 +367,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     private final SetOnce<BlobStore> blobStore = new SetOnce<>();
 
-    private final ClusterService clusterService;
+    protected final ClusterService clusterService;
 
     private final RecoverySettings recoverySettings;
 
@@ -318,7 +392,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
      *     <li>All repositories that are read-only, i.e. for which {@link #isReadOnly()} returns {@code true} because there are no
      *     guarantees that another cluster is not writing to the repository at the same time</li>
      *     <li>The node finds itself in a mixed-version cluster containing nodes older than
-     *     {@link RepositoryMetadata#REPO_GEN_IN_CS_VERSION} where the master node does not update the value of
+     *     {@link RepositoryMetadata#REPO_GEN_IN_CS_VERSION} where the cluster-manager node does not update the value of
      *     {@link RepositoryMetadata#generation()} when writing a new {@code index-N} blob</li>
      *     <li>The value of {@link RepositoryMetadata#generation()} for this repository is {@link RepositoryData#UNKNOWN_REPO_GEN}
      *     indicating that no consistent repository generation is tracked in the cluster state yet.</li>
@@ -330,32 +404,54 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
     /**
      * IO buffer size hint for reading and writing to the underlying blob store.
      */
-    protected final int bufferSize;
+    protected volatile int bufferSize;
 
     /**
      * Constructs new BlobStoreRepository
-     * @param metadata   The metadata for this repository including name and settings
+     * @param repositoryMetadata   The metadata for this repository including name and settings
      * @param clusterService ClusterService
      */
     protected BlobStoreRepository(
-        final RepositoryMetadata metadata,
-        final boolean compress,
+        final RepositoryMetadata repositoryMetadata,
         final NamedXContentRegistry namedXContentRegistry,
         final ClusterService clusterService,
         final RecoverySettings recoverySettings
     ) {
-        this.compress = compress;
-        this.metadata = metadata;
+        // Read RepositoryMetadata as the first step
+        readRepositoryMetadata(repositoryMetadata);
+
+        isSystemRepository = SYSTEM_REPOSITORY_SETTING.get(metadata.settings());
         this.namedXContentRegistry = namedXContentRegistry;
         this.threadPool = clusterService.getClusterApplierService().threadPool();
         this.clusterService = clusterService;
         this.recoverySettings = recoverySettings;
-        this.supportURLRepo = SUPPORT_URL_REPO.get(metadata.settings());
+    }
+
+    @Override
+    public void reload(RepositoryMetadata repositoryMetadata) {
+        readRepositoryMetadata(repositoryMetadata);
+    }
+
+    /**
+     * Reloads the values derived from the Repository Metadata
+     *
+     * @param repositoryMetadata RepositoryMetadata instance to derive the values from
+     */
+    private void readRepositoryMetadata(RepositoryMetadata repositoryMetadata) {
+        this.metadata = repositoryMetadata;
+
+        supportURLRepo = SUPPORT_URL_REPO.get(metadata.settings());
         snapshotRateLimiter = getRateLimiter(metadata.settings(), "max_snapshot_bytes_per_sec", new ByteSizeValue(40, ByteSizeUnit.MB));
         restoreRateLimiter = getRateLimiter(metadata.settings(), "max_restore_bytes_per_sec", ByteSizeValue.ZERO);
-        readOnly = metadata.settings().getAsBoolean("readonly", false);
+        remoteUploadRateLimiter = getRateLimiter(metadata.settings(), "max_remote_upload_bytes_per_sec", ByteSizeValue.ZERO);
+        remoteDownloadRateLimiter = getRateLimiter(metadata.settings(), "max_remote_download_bytes_per_sec", ByteSizeValue.ZERO);
+        readOnly = READONLY_SETTING.get(metadata.settings());
         cacheRepositoryData = CACHE_REPOSITORY_DATA.get(metadata.settings());
         bufferSize = Math.toIntExact(BUFFER_SIZE_SETTING.get(metadata.settings()).getBytes());
+        maxShardBlobDeleteBatch = MAX_SNAPSHOT_SHARD_BLOB_DELETE_BATCH_SIZE.get(metadata.settings());
+        compressor = COMPRESS_SETTING.get(metadata.settings())
+            ? COMPRESSION_TYPE_SETTING.get(metadata.settings())
+            : CompressorRegistry.none();
     }
 
     @Override
@@ -437,6 +533,11 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                 public TimeValue timeout() {
                     return updateTask.timeout();
                 }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return updateTask.getClusterManagerThrottlingKey();
+                }
             });
         }, onFailure));
     }
@@ -459,8 +560,8 @@ public void cloneShardSnapshot(
         executor.execute(ActionRunnable.supply(listener, () -> {
             final long startTime = threadPool.absoluteTimeInMillis();
             final BlobContainer shardContainer = shardContainer(index, shardNum);
-            final BlobStoreIndexShardSnapshots existingSnapshots;
             final String newGen;
+            final BlobStoreIndexShardSnapshots existingSnapshots;
             final String existingShardGen;
             if (shardGeneration == null) {
                 Tuple<BlobStoreIndexShardSnapshots, Long> tuple = buildBlobStoreIndexShardSnapshots(
@@ -513,24 +614,77 @@ public void cloneShardSnapshot(
                         + "]. A snapshot by that name already exists for this shard."
                 );
             }
-            final BlobStoreIndexShardSnapshot sourceMeta = loadShardSnapshot(shardContainer, source);
+            // We don't need to check if there exists a shallow snapshot with the same name as we have the check before starting the clone
+            // operation ensuring that the snapshot name is available by checking the repository data. Also, the new clone snapshot would
+            // have a different UUID and hence a new unique snap-N file will be created.
+            IndexShardSnapshot indexShardSnapshot = loadShardSnapshot(shardContainer, source);
+            assert indexShardSnapshot instanceof BlobStoreIndexShardSnapshot
+                : "indexShardSnapshot should be an instance of BlobStoreIndexShardSnapshot";
+            final BlobStoreIndexShardSnapshot sourceMeta = (BlobStoreIndexShardSnapshot) indexShardSnapshot;
             logger.trace("[{}] [{}] writing shard snapshot file for clone", shardId, target);
             INDEX_SHARD_SNAPSHOT_FORMAT.write(
                 sourceMeta.asClone(target.getName(), startTime, threadPool.absoluteTimeInMillis() - startTime),
                 shardContainer,
                 target.getUUID(),
-                compress
+                compressor
             );
             INDEX_SHARD_SNAPSHOTS_FORMAT.write(
                 existingSnapshots.withClone(source.getName(), target.getName()),
                 shardContainer,
                 newGen,
-                compress
+                compressor
             );
             return newGen;
         }));
     }
 
+    @Override
+    public void cloneRemoteStoreIndexShardSnapshot(
+        SnapshotId source,
+        SnapshotId target,
+        RepositoryShardId shardId,
+        @Nullable String shardGeneration,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<String> listener
+    ) {
+        if (isReadOnly()) {
+            listener.onFailure(new RepositoryException(metadata.name(), "cannot clone shard snapshot on a readonly repository"));
+            return;
+        }
+        final IndexId index = shardId.index();
+        final int shardNum = shardId.shardId();
+        final Executor executor = threadPool.executor(ThreadPool.Names.SNAPSHOT);
+        executor.execute(ActionRunnable.supply(listener, () -> {
+            final long startTime = threadPool.relativeTimeInMillis();
+            final BlobContainer shardContainer = shardContainer(index, shardNum);
+            // We don't need to check if there exists a shallow/full copy snapshot with the same name as we have the check before starting
+            // the clone operation ensuring that the snapshot name is available by checking the repository data. Also, the new clone shallow
+            // snapshot would have a different UUID and hence a new unique shallow-snap-N file will be created.
+            IndexShardSnapshot indexShardSnapshot = loadShardSnapshot(shardContainer, source);
+            assert indexShardSnapshot instanceof RemoteStoreShardShallowCopySnapshot
+                : "indexShardSnapshot should be an instance of RemoteStoreShardShallowCopySnapshot";
+            RemoteStoreShardShallowCopySnapshot remStoreBasedShardMetadata = (RemoteStoreShardShallowCopySnapshot) indexShardSnapshot;
+            String indexUUID = remStoreBasedShardMetadata.getIndexUUID();
+            String remoteStoreRepository = remStoreBasedShardMetadata.getRemoteStoreRepository();
+            RemoteStoreLockManager remoteStoreMetadataLockManger = remoteStoreLockManagerFactory.newLockManager(
+                remoteStoreRepository,
+                indexUUID,
+                String.valueOf(shardId.shardId())
+            );
+            remoteStoreMetadataLockManger.cloneLock(
+                FileLockInfo.getLockInfoBuilder().withAcquirerId(source.getUUID()).build(),
+                FileLockInfo.getLockInfoBuilder().withAcquirerId(target.getUUID()).build()
+            );
+            REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.write(
+                remStoreBasedShardMetadata.asClone(target.getName(), startTime, threadPool.absoluteTimeInMillis() - startTime),
+                shardContainer,
+                target.getUUID(),
+                compressor
+            );
+            return shardGeneration;
+        }));
+    }
+
     // Inspects all cluster state elements that contain a hint about what the current repository generation is and updates
     // #latestKnownRepoGen if a newer than currently known generation is found
     @Override
@@ -628,8 +782,6 @@ protected BlobContainer blobContainer() {
      * Public for testing.
      */
     public BlobStore blobStore() {
-        assertSnapshotOrGenericThread();
-
         BlobStore store = blobStore.get();
         if (store == null) {
             synchronized (lock) {
@@ -640,6 +792,9 @@ public BlobStore blobStore() {
                     }
                     try {
                         store = createBlobStore();
+                        if (metadata.cryptoMetadata() != null) {
+                            store = new EncryptedBlobStore(store, metadata.cryptoMetadata());
+                        }
                     } catch (RepositoryException e) {
                         throw e;
                     } catch (Exception e) {
@@ -668,7 +823,7 @@ public BlobStore blobStore() {
      * @return true if compression is needed
      */
     protected final boolean isCompress() {
-        return compress;
+        return compressor != CompressorRegistry.none();
     }
 
     /**
@@ -687,6 +842,14 @@ public RepositoryMetadata getMetadata() {
         return metadata;
     }
 
+    public NamedXContentRegistry getNamedXContentRegistry() {
+        return namedXContentRegistry;
+    }
+
+    public Compressor getCompressor() {
+        return compressor;
+    }
+
     @Override
     public RepositoryStats stats() {
         final BlobStore store = blobStore.get();
@@ -700,22 +863,27 @@ public RepositoryStats stats() {
     public void initializeSnapshot(SnapshotId snapshotId, List<IndexId> indices, Metadata clusterMetadata) {
         try {
             // Write Global Metadata
-            GLOBAL_METADATA_FORMAT.write(clusterMetadata, blobContainer(), snapshotId.getUUID(), compress);
+            GLOBAL_METADATA_FORMAT.write(clusterMetadata, blobContainer(), snapshotId.getUUID(), compressor);
 
             // write the index metadata for each index in the snapshot
             for (IndexId index : indices) {
-                INDEX_METADATA_FORMAT.write(clusterMetadata.index(index.getName()), indexContainer(index), snapshotId.getUUID(), compress);
+                INDEX_METADATA_FORMAT.write(
+                    clusterMetadata.index(index.getName()),
+                    indexContainer(index),
+                    snapshotId.getUUID(),
+                    compressor
+                );
             }
         } catch (IOException ex) {
             throw new SnapshotCreationException(metadata.name(), snapshotId, ex);
         }
     }
 
-    @Override
-    public void deleteSnapshots(
+    public void deleteSnapshotsAndReleaseLockFiles(
         Collection<SnapshotId> snapshotIds,
         long repositoryStateId,
         Version repositoryMetaVersion,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<RepositoryData> listener
     ) {
         if (isReadOnly()) {
@@ -726,8 +894,8 @@ public void deleteSnapshots(
                 protected void doRun() throws Exception {
                     final Map<String, BlobMetadata> rootBlobs = blobContainer().listBlobs();
                     final RepositoryData repositoryData = safeRepositoryData(repositoryStateId, rootBlobs);
-                    // Cache the indices that were found before writing out the new index-N blob so that a stuck master will never
-                    // delete an index that was created by another master node after writing this index-N blob.
+                    // Cache the indices that were found before writing out the new index-N blob so that a stuck cluster-manager will never
+                    // delete an index that was created by another cluster-manager node after writing this index-N blob.
                     final Map<String, BlobContainer> foundIndices = blobStore().blobContainer(indicesPath()).children();
                     doDeleteShardSnapshots(
                         snapshotIds,
@@ -736,6 +904,7 @@ protected void doRun() throws Exception {
                         rootBlobs,
                         repositoryData,
                         repositoryMetaVersion,
+                        remoteStoreLockManagerFactory,
                         listener
                     );
                 }
@@ -748,6 +917,22 @@ public void onFailure(Exception e) {
         }
     }
 
+    @Override
+    public void deleteSnapshots(
+        Collection<SnapshotId> snapshotIds,
+        long repositoryStateId,
+        Version repositoryMetaVersion,
+        ActionListener<RepositoryData> listener
+    ) {
+        deleteSnapshotsAndReleaseLockFiles(
+            snapshotIds,
+            repositoryStateId,
+            repositoryMetaVersion,
+            null, // Passing null since no remote store lock files need to be cleaned up.
+            listener
+        );
+    }
+
     /**
      * Loads {@link RepositoryData} ensuring that it is consistent with the given {@code rootBlobs} as well of the assumed generation.
      *
@@ -797,16 +982,18 @@ private RepositoryData safeRepositoryData(long repositoryStateId, Map<String, Bl
 
     /**
      * After updating the {@link RepositoryData} each of the shards directories is individually first moved to the next shard generation
-     * and then has all now unreferenced blobs in it deleted.
+     * and then has all now unreferenced blobs in it deleted. If remoteStoreLockManagerFactory is not null, remotestore lock files are
+     * released when deleting the respective shallow-snap-UUID blobs.
      *
-     * @param snapshotIds       SnapshotIds to delete
-     * @param repositoryStateId Expected repository state id
-     * @param foundIndices      All indices folders found in the repository before executing any writes to the repository during this
-     *                          delete operation
-     * @param rootBlobs         All blobs found at the root of the repository before executing any writes to the repository during this
-     *                          delete operation
-     * @param repositoryData    RepositoryData found the in the repository before executing this delete
-     * @param listener          Listener to invoke once finished
+     * @param snapshotIds                   SnapshotIds to delete
+     * @param repositoryStateId             Expected repository state id
+     * @param foundIndices                  All indices folders found in the repository before executing any writes to the repository during this
+     *                                      delete operation
+     * @param rootBlobs                     All blobs found at the root of the repository before executing any writes to the repository during this
+     *                                      delete operation
+     * @param repositoryData                RepositoryData found the in the repository before executing this delete
+     * @param remoteStoreLockManagerFactory RemoteStoreLockManagerFactory to be used for cleaning up remote store lock files
+     * @param listener                      Listener to invoke once finished
      */
     private void doDeleteShardSnapshots(
         Collection<SnapshotId> snapshotIds,
@@ -815,13 +1002,19 @@ private void doDeleteShardSnapshots(
         Map<String, BlobMetadata> rootBlobs,
         RepositoryData repositoryData,
         Version repoMetaVersion,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<RepositoryData> listener
     ) {
-
         if (SnapshotsService.useShardGenerations(repoMetaVersion)) {
             // First write the new shard state metadata (with the removed snapshot) and compute deletion targets
             final StepListener<Collection<ShardSnapshotMetaDeleteResult>> writeShardMetaDataAndComputeDeletesStep = new StepListener<>();
-            writeUpdatedShardMetaDataAndComputeDeletes(snapshotIds, repositoryData, true, writeShardMetaDataAndComputeDeletesStep);
+            writeUpdatedShardMetaDataAndComputeDeletes(
+                snapshotIds,
+                repositoryData,
+                true,
+                remoteStoreLockManagerFactory,
+                writeShardMetaDataAndComputeDeletesStep
+            );
             // Once we have put the new shard-level metadata into place, we can update the repository metadata as follows:
             // 1. Remove the snapshots from the list of existing snapshots
             // 2. Update the index shard generations of all updated shard folders
@@ -851,11 +1044,19 @@ private void doDeleteShardSnapshots(
                     ActionListener.wrap(() -> listener.onResponse(updatedRepoData)),
                     2
                 );
-                cleanupUnlinkedRootAndIndicesBlobs(snapshotIds, foundIndices, rootBlobs, updatedRepoData, afterCleanupsListener);
+                cleanupUnlinkedRootAndIndicesBlobs(
+                    snapshotIds,
+                    foundIndices,
+                    rootBlobs,
+                    updatedRepoData,
+                    remoteStoreLockManagerFactory,
+                    afterCleanupsListener
+                );
                 asyncCleanupUnlinkedShardLevelBlobs(
                     repositoryData,
                     snapshotIds,
                     writeShardMetaDataAndComputeDeletesStep.result(),
+                    remoteStoreLockManagerFactory,
                     afterCleanupsListener
                 );
             }, listener::onFailure);
@@ -868,11 +1069,30 @@ private void doDeleteShardSnapshots(
                     ActionListener.wrap(() -> listener.onResponse(newRepoData)),
                     2
                 );
-                cleanupUnlinkedRootAndIndicesBlobs(snapshotIds, foundIndices, rootBlobs, newRepoData, afterCleanupsListener);
+                cleanupUnlinkedRootAndIndicesBlobs(
+                    snapshotIds,
+                    foundIndices,
+                    rootBlobs,
+                    newRepoData,
+                    remoteStoreLockManagerFactory,
+                    afterCleanupsListener
+                );
                 final StepListener<Collection<ShardSnapshotMetaDeleteResult>> writeMetaAndComputeDeletesStep = new StepListener<>();
-                writeUpdatedShardMetaDataAndComputeDeletes(snapshotIds, repositoryData, false, writeMetaAndComputeDeletesStep);
+                writeUpdatedShardMetaDataAndComputeDeletes(
+                    snapshotIds,
+                    repositoryData,
+                    false,
+                    remoteStoreLockManagerFactory,
+                    writeMetaAndComputeDeletesStep
+                );
                 writeMetaAndComputeDeletesStep.whenComplete(
-                    deleteResults -> asyncCleanupUnlinkedShardLevelBlobs(repositoryData, snapshotIds, deleteResults, afterCleanupsListener),
+                    deleteResults -> asyncCleanupUnlinkedShardLevelBlobs(
+                        repositoryData,
+                        snapshotIds,
+                        deleteResults,
+                        remoteStoreLockManagerFactory,
+                        afterCleanupsListener
+                    ),
                     afterCleanupsListener::onFailure
                 );
             }, listener::onFailure));
@@ -884,15 +1104,24 @@ private void cleanupUnlinkedRootAndIndicesBlobs(
         Map<String, BlobContainer> foundIndices,
         Map<String, BlobMetadata> rootBlobs,
         RepositoryData updatedRepoData,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<Void> listener
     ) {
-        cleanupStaleBlobs(deletedSnapshots, foundIndices, rootBlobs, updatedRepoData, ActionListener.map(listener, ignored -> null));
+        cleanupStaleBlobs(
+            deletedSnapshots,
+            foundIndices,
+            rootBlobs,
+            updatedRepoData,
+            remoteStoreLockManagerFactory,
+            ActionListener.map(listener, ignored -> null)
+        );
     }
 
     private void asyncCleanupUnlinkedShardLevelBlobs(
         RepositoryData oldRepositoryData,
         Collection<SnapshotId> snapshotIds,
         Collection<ShardSnapshotMetaDeleteResult> deleteResults,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<Void> listener
     ) {
         final List<String> filesToDelete = resolveFilesToDelete(oldRepositoryData, snapshotIds, deleteResults);
@@ -900,15 +1129,112 @@ private void asyncCleanupUnlinkedShardLevelBlobs(
             listener.onResponse(null);
             return;
         }
-        threadPool.executor(ThreadPool.Names.SNAPSHOT).execute(ActionRunnable.wrap(listener, l -> {
-            try {
-                deleteFromContainer(blobContainer(), filesToDelete);
-                l.onResponse(null);
-            } catch (Exception e) {
-                logger.warn(() -> new ParameterizedMessage("{} Failed to delete some blobs during snapshot delete", snapshotIds), e);
-                throw e;
+
+        try {
+            AtomicInteger counter = new AtomicInteger();
+            Collection<List<String>> subList = filesToDelete.stream()
+                .collect(Collectors.groupingBy(it -> counter.getAndIncrement() / maxShardBlobDeleteBatch))
+                .values();
+            final BlockingQueue<List<String>> staleFilesToDeleteInBatch = new LinkedBlockingQueue<>(subList);
+
+            final GroupedActionListener<Void> groupedListener = new GroupedActionListener<>(
+                ActionListener.wrap(r -> { listener.onResponse(null); }, listener::onFailure),
+                staleFilesToDeleteInBatch.size()
+            );
+
+            // Start as many workers as fit into the snapshot pool at once at the most
+            final int workers = Math.min(threadPool.info(ThreadPool.Names.SNAPSHOT).getMax(), staleFilesToDeleteInBatch.size());
+            for (int i = 0; i < workers; ++i) {
+                executeStaleShardDelete(staleFilesToDeleteInBatch, remoteStoreLockManagerFactory, groupedListener);
             }
-        }));
+
+        } catch (Exception e) {
+            // TODO: We shouldn't be blanket catching and suppressing all exceptions here and instead handle them safely upstream.
+            // Currently this catch exists as a stop gap solution to tackle unexpected runtime exceptions from implementations
+            // bubbling up and breaking the snapshot functionality.
+            assert false : e;
+            logger.warn(new ParameterizedMessage("[{}] Exception during cleanup of stale shard blobs", snapshotIds), e);
+            listener.onFailure(e);
+        }
+    }
+
+    // When remoteStoreLockManagerFactory is non-null, while deleting the files, lock files are also released before deletion of respective
+    // shallow-snap-UUID files. And if it is null, we just delete the stale shard blobs.
+    private void executeStaleShardDelete(
+        BlockingQueue<List<String>> staleFilesToDeleteInBatch,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        GroupedActionListener<Void> listener
+    ) throws InterruptedException {
+        List<String> filesToDelete = staleFilesToDeleteInBatch.poll(0L, TimeUnit.MILLISECONDS);
+        if (filesToDelete != null) {
+            threadPool.executor(ThreadPool.Names.SNAPSHOT).execute(ActionRunnable.wrap(listener, l -> {
+                try {
+                    if (remoteStoreLockManagerFactory != null) {
+                        for (String fileToDelete : filesToDelete) {
+                            if (fileToDelete.contains(SHALLOW_SNAPSHOT_PREFIX)) {
+                                String[] fileToDeletePath = fileToDelete.split("/");
+                                String indexId = fileToDeletePath[1];
+                                String shardId = fileToDeletePath[2];
+                                String shallowSnapBlob = fileToDeletePath[3];
+                                String snapshotUUID = shallowSnapBlob.substring(
+                                    SHALLOW_SNAPSHOT_PREFIX.length(),
+                                    shallowSnapBlob.length() - ".dat".length()
+                                );
+                                BlobContainer shardContainer = blobStore().blobContainer(indicesPath().add(indexId).add(shardId));
+                                RemoteStoreShardShallowCopySnapshot remoteStoreShardShallowCopySnapshot =
+                                    REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.read(
+                                        shardContainer,
+                                        snapshotUUID,
+                                        namedXContentRegistry
+                                    );
+                                String indexUUID = remoteStoreShardShallowCopySnapshot.getIndexUUID();
+                                String remoteStoreRepoForIndex = remoteStoreShardShallowCopySnapshot.getRemoteStoreRepository();
+                                // Releasing lock file before deleting the shallow-snap-UUID file because in case of any failure while
+                                // releasing the lock file, we would still have the shallow-snap-UUID file and that would be used during
+                                // next delete operation for releasing this lock file
+                                RemoteStoreLockManager remoteStoreMetadataLockManager = remoteStoreLockManagerFactory.newLockManager(
+                                    remoteStoreRepoForIndex,
+                                    indexUUID,
+                                    shardId
+                                );
+                                remoteStoreMetadataLockManager.release(
+                                    FileLockInfo.getLockInfoBuilder().withAcquirerId(snapshotUUID).build()
+                                );
+                                if (!isIndexPresent(clusterService, indexUUID)) {
+                                    // this is a temporary solution where snapshot deletion triggers remote store side
+                                    // cleanup if index is already deleted. We will add a poller in future to take
+                                    // care of remote store side cleanup.
+                                    // see https://github.com/opensearch-project/OpenSearch/issues/8469
+                                    new RemoteSegmentStoreDirectoryFactory(
+                                        remoteStoreLockManagerFactory.getRepositoriesService(),
+                                        threadPool,
+                                        recoverySettings
+                                    ).newDirectory(
+                                        remoteStoreRepoForIndex,
+                                        indexUUID,
+                                        new ShardId(Index.UNKNOWN_INDEX_NAME, indexUUID, Integer.valueOf(shardId))
+                                    ).close();
+                                }
+                            }
+                        }
+                    }
+                    // Deleting the shard blobs
+                    deleteFromContainer(blobContainer(), filesToDelete);
+                    l.onResponse(null);
+                } catch (Exception e) {
+                    logger.warn(
+                        () -> new ParameterizedMessage(
+                            "[{}] Failed to delete following blobs during snapshot delete : {}",
+                            metadata.name(),
+                            filesToDelete
+                        ),
+                        e
+                    );
+                    l.onFailure(e);
+                }
+                executeStaleShardDelete(staleFilesToDeleteInBatch, remoteStoreLockManagerFactory, listener);
+            }));
+        }
     }
 
     // updates the shard state metadata for shards of a snapshot that is to be deleted. Also computes the files to be cleaned up.
@@ -916,6 +1242,7 @@ private void writeUpdatedShardMetaDataAndComputeDeletes(
         Collection<SnapshotId> snapshotIds,
         RepositoryData oldRepositoryData,
         boolean useUUIDs,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<Collection<ShardSnapshotMetaDeleteResult>> onAllShardsCompleted
     ) {
 
@@ -988,17 +1315,30 @@ protected void doRun() throws Exception {
                             final Set<String> blobs = shardContainer.listBlobs().keySet();
                             final BlobStoreIndexShardSnapshots blobStoreIndexShardSnapshots;
                             final long newGen;
-                            if (useUUIDs) {
-                                newGen = -1L;
-                                blobStoreIndexShardSnapshots = buildBlobStoreIndexShardSnapshots(
-                                    blobs,
-                                    shardContainer,
-                                    oldRepositoryData.shardGenerations().getShardGen(indexId, finalShardId)
-                                ).v1();
+
+                            // Index-N file would be present if snapshots other than shallow snapshots are present for this shard
+                            if (blobs.stream()
+                                .filter(blob -> blob.startsWith(SNAPSHOT_INDEX_PREFIX))
+                                .collect(Collectors.toSet())
+                                .size() > 0) {
+                                if (useUUIDs) {
+                                    newGen = -1L;
+                                    blobStoreIndexShardSnapshots = buildBlobStoreIndexShardSnapshots(
+                                        blobs,
+                                        shardContainer,
+                                        oldRepositoryData.shardGenerations().getShardGen(indexId, finalShardId)
+                                    ).v1();
+                                } else {
+                                    Tuple<BlobStoreIndexShardSnapshots, Long> tuple = buildBlobStoreIndexShardSnapshots(
+                                        blobs,
+                                        shardContainer
+                                    );
+                                    newGen = tuple.v2() + 1;
+                                    blobStoreIndexShardSnapshots = tuple.v1();
+                                }
                             } else {
-                                Tuple<BlobStoreIndexShardSnapshots, Long> tuple = buildBlobStoreIndexShardSnapshots(blobs, shardContainer);
-                                newGen = tuple.v2() + 1;
-                                blobStoreIndexShardSnapshots = tuple.v1();
+                                newGen = -1L;
+                                blobStoreIndexShardSnapshots = BlobStoreIndexShardSnapshots.EMPTY;
                             }
                             allShardsListener.onResponse(
                                 deleteFromShardSnapshotMeta(
@@ -1009,7 +1349,8 @@ protected void doRun() throws Exception {
                                     shardContainer,
                                     blobs,
                                     blobStoreIndexShardSnapshots,
-                                    newGen
+                                    newGen,
+                                    remoteStoreLockManagerFactory
                                 )
                             );
                         }
@@ -1060,20 +1401,23 @@ private List<String> resolveFilesToDelete(
     /**
      * Cleans up stale blobs directly under the repository root as well as all indices paths that aren't referenced by any existing
      * snapshots. This method is only to be called directly after a new {@link RepositoryData} was written to the repository and with
-     * parameters {@code foundIndices}, {@code rootBlobs}
+     * parameters {@code foundIndices}, {@code rootBlobs}. If remoteStoreLockManagerFactory is not null, remote store lock files are
+     * released when deleting the respective shallow-snap-UUID blobs.
      *
-     * @param deletedSnapshots if this method is called as part of a delete operation, the snapshot ids just deleted or empty if called as
-     *                         part of a repository cleanup
-     * @param foundIndices     all indices blob containers found in the repository before {@code newRepoData} was written
-     * @param rootBlobs        all blobs found directly under the repository root
-     * @param newRepoData      new repository data that was just written
-     * @param listener         listener to invoke with the combined {@link DeleteResult} of all blobs removed in this operation
+     * @param deletedSnapshots              if this method is called as part of a delete operation, the snapshot ids just deleted or empty if called as
+     *                                      part of a repository cleanup
+     * @param foundIndices                  all indices blob containers found in the repository before {@code newRepoData} was written
+     * @param rootBlobs                     all blobs found directly under the repository root
+     * @param newRepoData                   new repository data that was just written
+     * @param remoteStoreLockManagerFactory RemoteStoreLockManagerFactory to be used for cleaning up remote store lock files.
+     * @param listener                      listener to invoke with the combined {@link DeleteResult} of all blobs removed in this operation
      */
     private void cleanupStaleBlobs(
         Collection<SnapshotId> deletedSnapshots,
         Map<String, BlobContainer> foundIndices,
         Map<String, BlobMetadata> rootBlobs,
         RepositoryData newRepoData,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         ActionListener<DeleteResult> listener
     ) {
         final GroupedActionListener<DeleteResult> groupedListener = new GroupedActionListener<>(ActionListener.wrap(deleteResults -> {
@@ -1099,24 +1443,31 @@ private void cleanupStaleBlobs(
         if (foundIndices.keySet().equals(survivingIndexIds)) {
             groupedListener.onResponse(DeleteResult.ZERO);
         } else {
-            cleanupStaleIndices(foundIndices, survivingIndexIds, groupedListener);
+            cleanupStaleIndices(foundIndices, survivingIndexIds, remoteStoreLockManagerFactory, groupedListener);
         }
     }
 
     /**
      * Runs cleanup actions on the repository. Increments the repository state id by one before executing any modifications on the
-     * repository.
+     * repository. If remoteStoreLockManagerFactory is not null, remote store lock files are released when deleting the respective
+     * shallow-snap-UUID blobs.
      * TODO: Add shard level cleanups
      * TODO: Add unreferenced index metadata cleanup
      * <ul>
      *     <li>Deleting stale indices {@link #cleanupStaleIndices}</li>
      *     <li>Deleting unreferenced root level blobs {@link #cleanupStaleRootFiles}</li>
      * </ul>
-     * @param repositoryStateId     Current repository state id
-     * @param repositoryMetaVersion version of the updated repository metadata to write
-     * @param listener              Listener to complete when done
+     * @param repositoryStateId             Current repository state id
+     * @param repositoryMetaVersion         version of the updated repository metadata to write
+     * @param remoteStoreLockManagerFactory RemoteStoreLockManagerFactory to be used for cleaning up remote store lock files.
+     * @param listener                      Listener to complete when done
      */
-    public void cleanup(long repositoryStateId, Version repositoryMetaVersion, ActionListener<RepositoryCleanupResult> listener) {
+    public void cleanup(
+        long repositoryStateId,
+        Version repositoryMetaVersion,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<RepositoryCleanupResult> listener
+    ) {
         try {
             if (isReadOnly()) {
                 throw new RepositoryException(metadata.name(), "cannot run cleanup on readonly repository");
@@ -1146,6 +1497,7 @@ public void cleanup(long repositoryStateId, Version repositoryMetaVersion, Actio
                             foundIndices,
                             rootBlobs,
                             repositoryData,
+                            remoteStoreLockManagerFactory,
                             ActionListener.map(listener, RepositoryCleanupResult::new)
                         ),
                         listener::onFailure
@@ -1237,6 +1589,7 @@ private List<String> cleanupStaleRootFiles(
     private void cleanupStaleIndices(
         Map<String, BlobContainer> foundIndices,
         Set<String> survivingIndexIds,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         GroupedActionListener<DeleteResult> listener
     ) {
         final GroupedActionListener<DeleteResult> groupedListener = new GroupedActionListener<>(ActionListener.wrap(deleteResults -> {
@@ -1261,7 +1614,7 @@ private void cleanupStaleIndices(
                 foundIndices.size() - survivingIndexIds.size()
             );
             for (int i = 0; i < workers; ++i) {
-                executeOneStaleIndexDelete(staleIndicesToDelete, groupedListener);
+                executeOneStaleIndexDelete(staleIndicesToDelete, remoteStoreLockManagerFactory, groupedListener);
             }
         } catch (Exception e) {
             // TODO: We shouldn't be blanket catching and suppressing all exceptions here and instead handle them safely upstream.
@@ -1272,8 +1625,18 @@ private void cleanupStaleIndices(
         }
     }
 
+    private static boolean isIndexPresent(ClusterService clusterService, String indexUUID) {
+        for (final IndexMetadata indexMetadata : clusterService.state().metadata().getIndices().values()) {
+            if (indexUUID.equals(indexMetadata.getIndexUUID())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     private void executeOneStaleIndexDelete(
         BlockingQueue<Map.Entry<String, BlobContainer>> staleIndicesToDelete,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
         GroupedActionListener<DeleteResult> listener
     ) throws InterruptedException {
         Map.Entry<String, BlobContainer> indexEntry = staleIndicesToDelete.poll(0L, TimeUnit.MILLISECONDS);
@@ -1283,6 +1646,52 @@ private void executeOneStaleIndexDelete(
                 DeleteResult deleteResult = DeleteResult.ZERO;
                 try {
                     logger.debug("[{}] Found stale index [{}]. Cleaning it up", metadata.name(), indexSnId);
+                    if (remoteStoreLockManagerFactory != null) {
+                        Map<String, BlobContainer> shardBlobs = indexEntry.getValue().children();
+                        if (!shardBlobs.isEmpty()) {
+                            for (Map.Entry<String, BlobContainer> shardBlob : shardBlobs.entrySet()) {
+                                Map<String, BlobMetadata> shardLevelBlobs = shardBlob.getValue().listBlobs();
+                                for (Map.Entry<String, BlobMetadata> shardLevelBlob : shardLevelBlobs.entrySet()) {
+                                    String blob = shardLevelBlob.getKey();
+                                    String snapshotUUID = blob.substring(SHALLOW_SNAPSHOT_PREFIX.length(), blob.length() - ".dat".length());
+                                    if (blob.startsWith(SHALLOW_SNAPSHOT_PREFIX) && blob.endsWith(".dat")) {
+                                        RemoteStoreShardShallowCopySnapshot remoteStoreShardShallowCopySnapshot =
+                                            REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.read(
+                                                shardBlob.getValue(),
+                                                snapshotUUID,
+                                                namedXContentRegistry
+                                            );
+                                        String indexUUID = remoteStoreShardShallowCopySnapshot.getIndexUUID();
+                                        String remoteStoreRepoForIndex = remoteStoreShardShallowCopySnapshot.getRemoteStoreRepository();
+                                        // Releasing lock files before deleting the shallow-snap-UUID file because in case of any failure
+                                        // while releasing the lock file, we would still have the corresponding shallow-snap-UUID file
+                                        // and that would be used during next delete operation for releasing this stale lock file
+                                        RemoteStoreLockManager remoteStoreMetadataLockManager = remoteStoreLockManagerFactory
+                                            .newLockManager(remoteStoreRepoForIndex, indexUUID, shardBlob.getKey());
+                                        remoteStoreMetadataLockManager.release(
+                                            FileLockInfo.getLockInfoBuilder().withAcquirerId(snapshotUUID).build()
+                                        );
+                                        if (!isIndexPresent(clusterService, indexUUID)) {
+                                            // this is a temporary solution where snapshot deletion triggers remote store side
+                                            // cleanup if index is already deleted. We will add a poller in future to take
+                                            // care of remote store side cleanup.
+                                            // see https://github.com/opensearch-project/OpenSearch/issues/8469
+                                            new RemoteSegmentStoreDirectoryFactory(
+                                                remoteStoreLockManagerFactory.getRepositoriesService(),
+                                                threadPool,
+                                                recoverySettings
+                                            ).newDirectory(
+                                                remoteStoreRepoForIndex,
+                                                indexUUID,
+                                                new ShardId(Index.UNKNOWN_INDEX_NAME, indexUUID, Integer.valueOf(shardBlob.getKey()))
+                                            ).close();
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                    // Deleting the index folder
                     deleteResult = indexEntry.getValue().delete();
                     logger.debug("[{}] Cleaned up stale index [{}]", metadata.name(), indexSnId);
                 } catch (IOException e) {
@@ -1300,7 +1709,7 @@ private void executeOneStaleIndexDelete(
                     logger.warn(new ParameterizedMessage("[{}] Exception during single stale index delete", metadata.name()), e);
                 }
 
-                executeOneStaleIndexDelete(staleIndicesToDelete, listener);
+                executeOneStaleIndexDelete(staleIndicesToDelete, remoteStoreLockManagerFactory, listener);
                 return deleteResult;
             }));
         }
@@ -1371,9 +1780,9 @@ public void finalizeSnapshot(
                 );
             }, onUpdateFailure), 2 + indices.size());
 
-            // We ignore all FileAlreadyExistsException when writing metadata since otherwise a master failover while in this method will
-            // mean that no snap-${uuid}.dat blob is ever written for this snapshot. This is safe because any updated version of the
-            // index or global metadata will be compatible with the segments written in this snapshot as well.
+            // We ignore all FileAlreadyExistsException when writing metadata since otherwise a cluster-manager failover
+            // while in this method will mean that no snap-${uuid}.dat blob is ever written for this snapshot. This is safe because
+            // any updated version of the index or global metadata will be compatible with the segments written in this snapshot as well.
             // Failing on an already existing index-${repoGeneration} below ensures that the index.latest blob is not updated in a way
             // that decrements the generation it points at
 
@@ -1381,7 +1790,7 @@ public void finalizeSnapshot(
             executor.execute(
                 ActionRunnable.run(
                     allMetaListener,
-                    () -> GLOBAL_METADATA_FORMAT.write(clusterMetadata, blobContainer(), snapshotId.getUUID(), compress)
+                    () -> GLOBAL_METADATA_FORMAT.write(clusterMetadata, blobContainer(), snapshotId.getUUID(), compressor)
                 )
             );
 
@@ -1395,7 +1804,7 @@ public void finalizeSnapshot(
                         if (metaUUID == null) {
                             // We don't yet have this version of the metadata so we write it
                             metaUUID = UUIDs.base64UUID();
-                            INDEX_METADATA_FORMAT.write(indexMetaData, indexContainer(index), metaUUID, compress);
+                            INDEX_METADATA_FORMAT.write(indexMetaData, indexContainer(index), metaUUID, compressor);
                             indexMetaIdentifiers.put(identifiers, metaUUID);
                         }
                         indexMetas.put(index, identifiers);
@@ -1404,7 +1813,7 @@ public void finalizeSnapshot(
                             clusterMetadata.index(index.getName()),
                             indexContainer(index),
                             snapshotId.getUUID(),
-                            compress
+                            compressor
                         );
                     }
                 }));
@@ -1412,7 +1821,7 @@ public void finalizeSnapshot(
             executor.execute(
                 ActionRunnable.run(
                     allMetaListener,
-                    () -> SNAPSHOT_FORMAT.write(snapshotInfo, blobContainer(), snapshotId.getUUID(), compress)
+                    () -> SNAPSHOT_FORMAT.write(snapshotInfo, blobContainer(), snapshotId.getUUID(), compressor)
                 )
             );
         }, onUpdateFailure);
@@ -1521,6 +1930,16 @@ public long getRestoreThrottleTimeInNanos() {
         return restoreRateLimitingTimeInNanos.count();
     }
 
+    @Override
+    public long getRemoteUploadThrottleTimeInNanos() {
+        return remoteUploadRateLimitingTimeInNanos.count();
+    }
+
+    @Override
+    public long getRemoteDownloadThrottleTimeInNanos() {
+        return remoteDownloadRateLimitingTimeInNanos.count();
+    }
+
     protected void assertSnapshotOrGenericThread() {
         assert Thread.currentThread().getName().contains('[' + ThreadPool.Names.SNAPSHOT + ']')
             || Thread.currentThread().getName().contains('[' + ThreadPool.Names.GENERIC + ']') : "Expected current thread ["
@@ -1540,13 +1959,19 @@ public String startVerification() {
                 byte[] testBytes = Strings.toUTF8Bytes(seed);
                 BlobContainer testContainer = blobStore().blobContainer(basePath().add(testBlobPrefix(seed)));
                 BytesArray bytes = new BytesArray(testBytes);
-                try (InputStream stream = bytes.streamInput()) {
-                    testContainer.writeBlobAtomic("master.dat", stream, bytes.length(), true);
+                if (isSystemRepository == false) {
+                    try (InputStream stream = bytes.streamInput()) {
+                        testContainer.writeBlobAtomic("master.dat", stream, bytes.length(), true);
+                    }
                 }
                 return seed;
             }
         } catch (Exception exp) {
-            throw new RepositoryVerificationException(metadata.name(), "path " + basePath() + " is not accessible on master node", exp);
+            throw new RepositoryVerificationException(
+                metadata.name(),
+                "path " + basePath() + " is not accessible on cluster-manager node",
+                exp
+            );
         }
     }
 
@@ -1688,7 +2113,7 @@ private void cacheRepositoryData(BytesReference updated, long generation) {
         if (cacheRepositoryData && bestEffortConsistency == false) {
             final BytesReference serialized;
             try {
-                serialized = CompressorFactory.COMPRESSOR.compress(updated);
+                serialized = CompressorRegistry.defaultCompressor().compress(updated);
                 final int len = serialized.length();
                 if (len > ByteSizeUnit.KB.toBytes(500)) {
                     logger.debug(
@@ -1724,9 +2149,9 @@ private void cacheRepositoryData(BytesReference updated, long generation) {
     }
 
     private RepositoryData repositoryDataFromCachedEntry(Tuple<Long, BytesReference> cacheEntry) throws IOException {
-        try (InputStream input = CompressorFactory.COMPRESSOR.threadLocalInputStream(cacheEntry.v2().streamInput())) {
+        try (InputStream input = CompressorRegistry.defaultCompressor().threadLocalInputStream(cacheEntry.v2().streamInput())) {
             return RepositoryData.snapshotsFromXContent(
-                XContentType.JSON.xContent().createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, input),
+                MediaTypeRegistry.JSON.xContent().createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, input),
                 cacheEntry.v1(),
                 false
             );
@@ -1815,12 +2240,12 @@ private RepositoryData getRepositoryData(long indexGen) {
             return RepositoryData.EMPTY;
         }
         try {
-            final String snapshotsIndexBlobName = INDEX_FILE_PREFIX + Long.toString(indexGen);
+            final String snapshotsIndexBlobName = INDEX_FILE_PREFIX + indexGen;
 
             // EMPTY is safe here because RepositoryData#fromXContent calls namedObject
             try (
                 InputStream blob = blobContainer().readBlob(snapshotsIndexBlobName);
-                XContentParser parser = XContentType.JSON.xContent()
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, blob)
             ) {
                 return RepositoryData.snapshotsFromXContent(parser, indexGen, true);
@@ -1847,6 +2272,11 @@ public boolean isReadOnly() {
         return readOnly;
     }
 
+    @Override
+    public boolean isSystemRepository() {
+        return isSystemRepository;
+    }
+
     /**
      * Writing a new index generation is a three step process.
      * First, the {@link RepositoryMetadata} entry for this repository is set into a pending state by incrementing its
@@ -2236,7 +2666,7 @@ long latestIndexBlobId() throws IOException {
 
     // package private for testing
     long readSnapshotIndexLatestBlob() throws IOException {
-        return Numbers.bytesToLong(Streams.readFully(blobContainer().readBlob(INDEX_LATEST_BLOB)).toBytesRef());
+        return BytesRefUtils.bytesToLong(Streams.readFully(blobContainer().readBlob(INDEX_LATEST_BLOB)).toBytesRef());
     }
 
     private long listBlobsToGetLatestIndexId() throws IOException {
@@ -2269,6 +2699,85 @@ private void writeAtomic(BlobContainer container, final String blobName, final B
         }
     }
 
+    @Override
+    public void snapshotRemoteStoreIndexShard(
+        Store store,
+        SnapshotId snapshotId,
+        IndexId indexId,
+        IndexCommit snapshotIndexCommit,
+        String shardStateIdentifier,
+        IndexShardSnapshotStatus snapshotStatus,
+        long primaryTerm,
+        long startTime,
+        ActionListener<String> listener
+    ) {
+        if (isReadOnly()) {
+            listener.onFailure(new RepositoryException(metadata.name(), "cannot snapshot shard on a readonly repository"));
+            return;
+        }
+        final ShardId shardId = store.shardId();
+        try {
+            final String generation = snapshotStatus.generation();
+            logger.info("[{}] [{}] snapshot to [{}] [{}] ...", shardId, snapshotId, metadata.name(), generation);
+            final BlobContainer shardContainer = shardContainer(indexId, shardId);
+
+            long indexTotalFileSize = 0;
+            // local store is being used here to fetch the files metadata instead of remote store as currently
+            // remote store is mirroring the local store.
+            List<String> fileNames = new ArrayList<>(snapshotIndexCommit.getFileNames());
+            Store.MetadataSnapshot commitSnapshotMetadata = store.getMetadata(snapshotIndexCommit);
+            for (String fileName : fileNames) {
+                indexTotalFileSize += commitSnapshotMetadata.get(fileName).length();
+            }
+            int indexTotalNumberOfFiles = fileNames.size();
+
+            snapshotStatus.moveToStarted(
+                startTime,
+                0, // incremental File Count is zero as we are storing the data as part of remote store.
+                indexTotalNumberOfFiles,
+                0, // incremental File Size is zero as we are storing the data as part of remote store.
+                indexTotalFileSize
+            );
+
+            final IndexShardSnapshotStatus.Copy lastSnapshotStatus = snapshotStatus.moveToFinalize(snapshotIndexCommit.getGeneration());
+
+            // now create and write the commit point
+            logger.trace("[{}] [{}] writing shard snapshot file", shardId, snapshotId);
+            try {
+                REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.write(
+                    new RemoteStoreShardShallowCopySnapshot(
+                        snapshotId.getName(),
+                        lastSnapshotStatus.getIndexVersion(),
+                        primaryTerm,
+                        snapshotIndexCommit.getGeneration(),
+                        lastSnapshotStatus.getStartTime(),
+                        threadPool.absoluteTimeInMillis() - lastSnapshotStatus.getStartTime(),
+                        indexTotalNumberOfFiles,
+                        indexTotalFileSize,
+                        store.indexSettings().getUUID(),
+                        store.indexSettings().getRemoteStoreRepository(),
+                        this.basePath().toString(),
+                        fileNames
+                    ),
+                    shardContainer,
+                    snapshotId.getUUID(),
+                    compressor
+                );
+            } catch (IOException e) {
+                throw new IndexShardSnapshotFailedException(
+                    shardId,
+                    "Failed to write commit point for snapshot " + snapshotId.getName() + "(" + snapshotId.getUUID() + ")",
+                    e
+                );
+            }
+            snapshotStatus.moveToDone(threadPool.absoluteTimeInMillis(), generation);
+            listener.onResponse(generation);
+
+        } catch (Exception e) {
+            listener.onFailure(e);
+        }
+    }
+
     @Override
     public void snapshotShard(
         Store store,
@@ -2422,7 +2931,7 @@ public void snapshotShard(
                 // reference a generation that has not had all its files fully upload.
                 indexGeneration = UUIDs.randomBase64UUID();
                 try {
-                    INDEX_SHARD_SNAPSHOTS_FORMAT.write(updatedBlobStoreIndexShardSnapshots, shardContainer, indexGeneration, compress);
+                    INDEX_SHARD_SNAPSHOTS_FORMAT.write(updatedBlobStoreIndexShardSnapshots, shardContainer, indexGeneration, compressor);
                 } catch (IOException e) {
                     throw new IndexShardSnapshotFailedException(
                         shardId,
@@ -2500,7 +3009,7 @@ public void snapshotShard(
                         ),
                         shardContainer,
                         snapshotId.getUUID(),
-                        compress
+                        compressor
                     );
                 } catch (IOException e) {
                     throw new IndexShardSnapshotFailedException(shardId, "Failed to write commit point", e);
@@ -2588,7 +3097,10 @@ public void restoreShard(
         final Executor executor = threadPool.executor(ThreadPool.Names.SNAPSHOT);
         final BlobContainer container = shardContainer(indexId, snapshotShardId);
         executor.execute(ActionRunnable.wrap(restoreListener, l -> {
-            final BlobStoreIndexShardSnapshot snapshot = loadShardSnapshot(container, snapshotId);
+            IndexShardSnapshot indexShardSnapshot = loadShardSnapshot(container, snapshotId);
+            assert indexShardSnapshot instanceof BlobStoreIndexShardSnapshot
+                : "indexShardSnapshot should be an instance of BlobStoreIndexShardSnapshot";
+            final BlobStoreIndexShardSnapshot snapshot = (BlobStoreIndexShardSnapshot) indexShardSnapshot;
             final SnapshotFiles snapshotFiles = new SnapshotFiles(snapshot.snapshot(), snapshot.indexFiles(), null);
             new FileRestoreContext(metadata.name(), shardId, snapshotId, recoveryState) {
                 @Override
@@ -2714,39 +3226,106 @@ private static ActionListener<Void> fileQueueListener(
         });
     }
 
-    private static InputStream maybeRateLimit(InputStream stream, Supplier<RateLimiter> rateLimiterSupplier, CounterMetric metric) {
-        return new RateLimitingInputStream(stream, rateLimiterSupplier, metric::inc);
+    private static void mayBeLogRateLimits(BlobStoreTransferContext context, RateLimiter rateLimiter, long time) {
+        logger.debug(
+            () -> new ParameterizedMessage(
+                "Rate limited blob store transfer, context [{}], for duration [{} ms] for configured rate [{} MBps]",
+                context,
+                TimeValue.timeValueNanos(time).millis(),
+                rateLimiter.getMBPerSec()
+            )
+        );
+    }
+
+    private static InputStream maybeRateLimit(
+        InputStream stream,
+        Supplier<RateLimiter> rateLimiterSupplier,
+        CounterMetric metric,
+        BlobStoreTransferContext context
+    ) {
+        return new RateLimitingInputStream(stream, rateLimiterSupplier, (t) -> {
+            mayBeLogRateLimits(context, rateLimiterSupplier.get(), t);
+            metric.inc(t);
+        });
+    }
+
+    private static OffsetRangeInputStream maybeRateLimitRemoteTransfers(
+        OffsetRangeInputStream offsetRangeInputStream,
+        Supplier<RateLimiter> rateLimiterSupplier,
+        CounterMetric metric,
+        BlobStoreTransferContext context
+    ) {
+        return new RateLimitingOffsetRangeInputStream(offsetRangeInputStream, rateLimiterSupplier, (t) -> {
+            mayBeLogRateLimits(context, rateLimiterSupplier.get(), t);
+            metric.inc(t);
+        });
     }
 
     public InputStream maybeRateLimitRestores(InputStream stream) {
         return maybeRateLimit(
-            maybeRateLimit(stream, () -> restoreRateLimiter, restoreRateLimitingTimeInNanos),
+            maybeRateLimit(stream, () -> restoreRateLimiter, restoreRateLimitingTimeInNanos, BlobStoreTransferContext.SNAPSHOT_RESTORE),
+            recoverySettings::rateLimiter,
+            restoreRateLimitingTimeInNanos,
+            BlobStoreTransferContext.SNAPSHOT_RESTORE
+        );
+    }
+
+    public OffsetRangeInputStream maybeRateLimitRemoteUploadTransfers(OffsetRangeInputStream offsetRangeInputStream) {
+        return maybeRateLimitRemoteTransfers(
+            offsetRangeInputStream,
+            () -> remoteUploadRateLimiter,
+            remoteUploadRateLimitingTimeInNanos,
+            BlobStoreTransferContext.REMOTE_UPLOAD
+        );
+    }
+
+    public InputStream maybeRateLimitRemoteDownloadTransfers(InputStream inputStream) {
+        return maybeRateLimit(
+            maybeRateLimit(
+                inputStream,
+                () -> remoteDownloadRateLimiter,
+                remoteDownloadRateLimitingTimeInNanos,
+                BlobStoreTransferContext.REMOTE_DOWNLOAD
+            ),
             recoverySettings::rateLimiter,
-            restoreRateLimitingTimeInNanos
+            remoteDownloadRateLimitingTimeInNanos,
+            BlobStoreTransferContext.REMOTE_DOWNLOAD
         );
     }
 
     public InputStream maybeRateLimitSnapshots(InputStream stream) {
-        return maybeRateLimit(stream, () -> snapshotRateLimiter, snapshotRateLimitingTimeInNanos);
+        return maybeRateLimit(stream, () -> snapshotRateLimiter, snapshotRateLimitingTimeInNanos, BlobStoreTransferContext.SNAPSHOT);
+    }
+
+    @Override
+    public List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        return Arrays.asList(SYSTEM_REPOSITORY_SETTING, READONLY_SETTING, REMOTE_STORE_INDEX_SHALLOW_COPY);
+    }
+
+    @Override
+    public RemoteStoreShardShallowCopySnapshot getRemoteStoreShallowCopyShardMetadata(
+        SnapshotId snapshotId,
+        IndexId indexId,
+        ShardId snapshotShardId
+    ) {
+        final BlobContainer container = shardContainer(indexId, snapshotShardId);
+        IndexShardSnapshot indexShardSnapshot = loadShardSnapshot(container, snapshotId);
+        assert indexShardSnapshot instanceof RemoteStoreShardShallowCopySnapshot
+            : "indexShardSnapshot should be an instance of RemoteStoreShardShallowCopySnapshot";
+        return (RemoteStoreShardShallowCopySnapshot) indexShardSnapshot;
     }
 
     @Override
     public IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, IndexId indexId, ShardId shardId) {
-        BlobStoreIndexShardSnapshot snapshot = loadShardSnapshot(shardContainer(indexId, shardId), snapshotId);
-        return IndexShardSnapshotStatus.newDone(
-            snapshot.startTime(),
-            snapshot.time(),
-            snapshot.incrementalFileCount(),
-            snapshot.totalFileCount(),
-            snapshot.incrementalSize(),
-            snapshot.totalSize(),
-            null
-        ); // Not adding a real generation here as it doesn't matter to callers
+        IndexShardSnapshot snapshot = loadShardSnapshot(shardContainer(indexId, shardId), snapshotId);
+        return snapshot.getIndexShardSnapshotStatus();
     }
 
     @Override
     public void verify(String seed, DiscoveryNode localNode) {
-        assertSnapshotOrGenericThread();
+        if (isSystemRepository == false) {
+            assertSnapshotOrGenericThread();
+        }
         if (isReadOnly()) {
             try {
                 latestIndexBlobId();
@@ -2771,30 +3350,33 @@ public void verify(String seed, DiscoveryNode localNode) {
                     exp
                 );
             }
-            try (InputStream masterDat = testBlobContainer.readBlob("master.dat")) {
-                final String seedRead = Streams.readFully(masterDat).utf8ToString();
-                if (seedRead.equals(seed) == false) {
+
+            if (isSystemRepository == false) {
+                try (InputStream masterDat = testBlobContainer.readBlob("master.dat")) {
+                    final String seedRead = Streams.readFully(masterDat).utf8ToString();
+                    if (seedRead.equals(seed) == false) {
+                        throw new RepositoryVerificationException(
+                            metadata.name(),
+                            "Seed read from master.dat was [" + seedRead + "] but expected seed [" + seed + "]"
+                        );
+                    }
+                } catch (NoSuchFileException e) {
                     throw new RepositoryVerificationException(
                         metadata.name(),
-                        "Seed read from master.dat was [" + seedRead + "] but expected seed [" + seed + "]"
+                        "a file written by cluster-manager to the store ["
+                            + blobStore()
+                            + "] cannot be accessed on the node ["
+                            + localNode
+                            + "]. "
+                            + "This might indicate that the store ["
+                            + blobStore()
+                            + "] is not shared between this node and the cluster-manager node or "
+                            + "that permissions on the store don't allow reading files written by the cluster-manager node",
+                        e
                     );
+                } catch (Exception e) {
+                    throw new RepositoryVerificationException(metadata.name(), "Failed to verify repository", e);
                 }
-            } catch (NoSuchFileException e) {
-                throw new RepositoryVerificationException(
-                    metadata.name(),
-                    "a file written by master to the store ["
-                        + blobStore()
-                        + "] cannot be accessed on the node ["
-                        + localNode
-                        + "]. "
-                        + "This might indicate that the store ["
-                        + blobStore()
-                        + "] is not shared between this node and the master node or "
-                        + "that permissions on the store don't allow reading files written by the master node",
-                    e
-                );
-            } catch (Exception e) {
-                throw new RepositoryVerificationException(metadata.name(), "Failed to verify repository", e);
             }
         }
     }
@@ -2818,7 +3400,8 @@ private ShardSnapshotMetaDeleteResult deleteFromShardSnapshotMeta(
         BlobContainer shardContainer,
         Set<String> blobs,
         BlobStoreIndexShardSnapshots snapshots,
-        long indexGeneration
+        long indexGeneration,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory
     ) {
         // Build a list of snapshots that should be preserved
         List<SnapshotFiles> newSnapshotsList = new ArrayList<>();
@@ -2830,23 +3413,37 @@ private ShardSnapshotMetaDeleteResult deleteFromShardSnapshotMeta(
         }
         String writtenGeneration = null;
         try {
-            if (newSnapshotsList.isEmpty()) {
+            // Using survivingSnapshots instead of newSnapshotsList as shallow snapshots can be present which won't be part of
+            // newSnapshotsList
+            if (survivingSnapshots.isEmpty()) {
+                // No shallow copy or full copy snapshot is surviving.
                 return new ShardSnapshotMetaDeleteResult(indexId, snapshotShardId, ShardGenerations.DELETED_SHARD_GEN, blobs);
             } else {
-                final BlobStoreIndexShardSnapshots updatedSnapshots = new BlobStoreIndexShardSnapshots(newSnapshotsList);
-                if (indexGeneration < 0L) {
-                    writtenGeneration = UUIDs.randomBase64UUID();
-                    INDEX_SHARD_SNAPSHOTS_FORMAT.write(updatedSnapshots, shardContainer, writtenGeneration, compress);
+                final BlobStoreIndexShardSnapshots updatedSnapshots;
+                // If we have surviving non shallow snapshots, update index- file.
+                if (newSnapshotsList.size() > 0) {
+                    // Some full copy snapshots are surviving.
+                    updatedSnapshots = new BlobStoreIndexShardSnapshots(newSnapshotsList);
+                    if (indexGeneration < 0L) {
+                        writtenGeneration = UUIDs.randomBase64UUID();
+                        INDEX_SHARD_SNAPSHOTS_FORMAT.write(updatedSnapshots, shardContainer, writtenGeneration, compressor);
+                    } else {
+                        writtenGeneration = String.valueOf(indexGeneration);
+                        writeShardIndexBlobAtomic(shardContainer, indexGeneration, updatedSnapshots);
+                    }
                 } else {
-                    writtenGeneration = String.valueOf(indexGeneration);
-                    writeShardIndexBlobAtomic(shardContainer, indexGeneration, updatedSnapshots);
+                    // Some shallow copy snapshots are surviving. In this case, since no full copy snapshots are present, we use
+                    // EMPTY BlobStoreIndexShardSnapshots for updatedSnapshots which is used in unusedBlobs to compute stale files,
+                    // and use DELETED_SHARD_GEN since index-N file would not be present anymore.
+                    updatedSnapshots = BlobStoreIndexShardSnapshots.EMPTY;
+                    writtenGeneration = ShardGenerations.DELETED_SHARD_GEN;
                 }
                 final Set<String> survivingSnapshotUUIDs = survivingSnapshots.stream().map(SnapshotId::getUUID).collect(Collectors.toSet());
                 return new ShardSnapshotMetaDeleteResult(
                     indexId,
                     snapshotShardId,
                     writtenGeneration,
-                    unusedBlobs(blobs, survivingSnapshotUUIDs, updatedSnapshots)
+                    unusedBlobs(blobs, survivingSnapshotUUIDs, updatedSnapshots, remoteStoreLockManagerFactory)
                 );
             }
         } catch (IOException e) {
@@ -2876,15 +3473,17 @@ private void writeShardIndexBlobAtomic(
             () -> new ParameterizedMessage("[{}] Writing shard index [{}] to [{}]", metadata.name(), indexGeneration, shardContainer.path())
         );
         final String blobName = INDEX_SHARD_SNAPSHOTS_FORMAT.blobName(String.valueOf(indexGeneration));
-        writeAtomic(shardContainer, blobName, INDEX_SHARD_SNAPSHOTS_FORMAT.serialize(updatedSnapshots, blobName, compress), true);
+        writeAtomic(shardContainer, blobName, INDEX_SHARD_SNAPSHOTS_FORMAT.serialize(updatedSnapshots, blobName, compressor), true);
     }
 
     // Unused blobs are all previous index-, data- and meta-blobs and that are not referenced by the new index- as well as all
-    // temporary blobs
+    // temporary blobs. If remoteStoreLockManagerFactory is non-null, the shallow-snap- files that do not belong to any of the
+    // surviving snapshots are also added for cleanup.
     private static List<String> unusedBlobs(
         Set<String> blobs,
         Set<String> survivingSnapshotUUIDs,
-        BlobStoreIndexShardSnapshots updatedSnapshots
+        BlobStoreIndexShardSnapshots updatedSnapshots,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory
     ) {
         return blobs.stream()
             .filter(
@@ -2894,6 +3493,13 @@ private static List<String> unusedBlobs(
                         && survivingSnapshotUUIDs.contains(
                             blob.substring(SNAPSHOT_PREFIX.length(), blob.length() - ".dat".length())
                         ) == false)
+                    || (remoteStoreLockManagerFactory != null
+                        ? (blob.startsWith(SHALLOW_SNAPSHOT_PREFIX)
+                            && blob.endsWith(".dat")
+                            && survivingSnapshotUUIDs.contains(
+                                blob.substring(SHALLOW_SNAPSHOT_PREFIX.length(), blob.length() - ".dat".length())
+                            ) == false)
+                        : false)
                     || (blob.startsWith(UPLOADED_DATA_BLOB_PREFIX) && updatedSnapshots.findNameFile(canonicalName(blob)) == null)
                     || FsBlobContainer.isTempBlobName(blob)
             )
@@ -2903,11 +3509,15 @@ private static List<String> unusedBlobs(
     /**
      * Loads information about shard snapshot
      */
-    public BlobStoreIndexShardSnapshot loadShardSnapshot(BlobContainer shardContainer, SnapshotId snapshotId) {
+    public IndexShardSnapshot loadShardSnapshot(BlobContainer shardContainer, SnapshotId snapshotId) {
         try {
-            return INDEX_SHARD_SNAPSHOT_FORMAT.read(shardContainer, snapshotId.getUUID(), namedXContentRegistry);
-        } catch (NoSuchFileException ex) {
-            throw new SnapshotMissingException(metadata.name(), snapshotId, ex);
+            if (shardContainer.blobExists(INDEX_SHARD_SNAPSHOT_FORMAT.blobName(snapshotId.getUUID()))) {
+                return INDEX_SHARD_SNAPSHOT_FORMAT.read(shardContainer, snapshotId.getUUID(), namedXContentRegistry);
+            } else if (shardContainer.blobExists(REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.blobName(snapshotId.getUUID()))) {
+                return REMOTE_STORE_SHARD_SHALLOW_COPY_SNAPSHOT_FORMAT.read(shardContainer, snapshotId.getUUID(), namedXContentRegistry);
+            } else {
+                throw new SnapshotMissingException(metadata.name(), snapshotId.getName());
+            }
         } catch (IOException ex) {
             throw new SnapshotException(
                 metadata.name(),
@@ -3057,4 +3667,22 @@ private static final class ShardSnapshotMetaDeleteResult {
             this.blobsToDelete = blobsToDelete;
         }
     }
+
+    enum BlobStoreTransferContext {
+        REMOTE_UPLOAD("remote_upload"),
+        REMOTE_DOWNLOAD("remote_download"),
+        SNAPSHOT("snapshot"),
+        SNAPSHOT_RESTORE("snapshot_restore");
+
+        private final String name;
+
+        BlobStoreTransferContext(String name) {
+            this.name = name;
+        }
+
+        @Override
+        public String toString() {
+            return name;
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/ChecksumBlobStoreFormat.java b/server/src/main/java/org/opensearch/repositories/blobstore/ChecksumBlobStoreFormat.java
index 467cfecfb9016..7e1960171043a 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/ChecksumBlobStoreFormat.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/ChecksumBlobStoreFormat.java
@@ -42,22 +42,28 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
 import org.opensearch.common.blobstore.BlobContainer;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.RemoteTransferContainer;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeIndexInputStream;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lucene.store.ByteArrayIndexInput;
 import org.opensearch.common.lucene.store.IndexOutputOutputStream;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.gateway.CorruptStateException;
+import org.opensearch.index.store.exception.ChecksumCombinationException;
 import org.opensearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
@@ -67,8 +73,12 @@
 import java.util.Locale;
 import java.util.Map;
 
+import static org.opensearch.common.blobstore.transfer.RemoteTransferContainer.checksumOfChecksum;
+
 /**
  * Snapshot metadata file format used in v2.0 and above
+ *
+ * @opensearch.internal
  */
 public final class ChecksumBlobStoreFormat<T extends ToXContent> {
 
@@ -157,15 +167,70 @@ public T deserialize(String blobName, NamedXContentRegistry namedXContentRegistr
      * @param obj                 object to be serialized
      * @param blobContainer       blob container
      * @param name                blob name
-     * @param compress            whether to use compression
+     * @param compressor          whether to use compression
      */
-    public void write(T obj, BlobContainer blobContainer, String name, boolean compress) throws IOException {
+    public void write(final T obj, final BlobContainer blobContainer, final String name, final Compressor compressor) throws IOException {
         final String blobName = blobName(name);
-        final BytesReference bytes = serialize(obj, blobName, compress);
+        final BytesReference bytes = serialize(obj, blobName, compressor);
         blobContainer.writeBlob(blobName, bytes.streamInput(), bytes.length(), false);
     }
 
-    public BytesReference serialize(final T obj, final String blobName, final boolean compress) throws IOException {
+    /**
+     * Writes blob with resolving the blob name using {@link #blobName} method.
+     * Leverages the multipart upload if supported by the blobContainer.
+     *
+     * @param obj                 object to be serialized
+     * @param blobContainer       blob container
+     * @param name                blob name
+     * @param compressor          whether to use compression
+     * @param listener            listener to listen to write result
+     */
+    public void writeAsync(
+        final T obj,
+        final BlobContainer blobContainer,
+        final String name,
+        final Compressor compressor,
+        ActionListener<Void> listener
+    ) throws IOException {
+        if (blobContainer instanceof AsyncMultiStreamBlobContainer == false) {
+            write(obj, blobContainer, name, compressor);
+            listener.onResponse(null);
+            return;
+        }
+        final String blobName = blobName(name);
+        final BytesReference bytes = serialize(obj, blobName, compressor);
+        final String resourceDescription = "ChecksumBlobStoreFormat.writeAsync(blob=\"" + blobName + "\")";
+        try (IndexInput input = new ByteArrayIndexInput(resourceDescription, BytesReference.toBytes(bytes))) {
+            long expectedChecksum;
+            try {
+                expectedChecksum = checksumOfChecksum(input.clone(), 8);
+            } catch (Exception e) {
+                throw new ChecksumCombinationException(
+                    "Potentially corrupted file: Checksum combination failed while combining stored checksum "
+                        + "and calculated checksum of stored checksum",
+                    resourceDescription,
+                    e
+                );
+            }
+
+            try (
+                RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                    blobName,
+                    blobName,
+                    bytes.length(),
+                    true,
+                    WritePriority.HIGH,
+                    (size, position) -> new OffsetRangeIndexInputStream(input, size, position),
+                    expectedChecksum,
+                    ((AsyncMultiStreamBlobContainer) blobContainer).remoteIntegrityCheckSupported()
+                )
+            ) {
+                ((AsyncMultiStreamBlobContainer) blobContainer).asyncBlobUpload(remoteTransferContainer.createWriteContext(), listener);
+            }
+        }
+    }
+
+    public BytesReference serialize(final T obj, final String blobName, final Compressor compressor) throws IOException {
         try (BytesStreamOutput outputStream = new BytesStreamOutput()) {
             try (
                 OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput(
@@ -183,9 +248,9 @@ public void close() throws IOException {
                         // in order to write the footer we need to prevent closing the actual index input.
                     }
                 };
-                    XContentBuilder builder = XContentFactory.contentBuilder(
+                    XContentBuilder builder = MediaTypeRegistry.contentBuilder(
                         XContentType.SMILE,
-                        compress ? CompressorFactory.COMPRESSOR.threadLocalOutputStream(indexOutputOutputStream) : indexOutputOutputStream
+                        compressor.threadLocalOutputStream(indexOutputOutputStream)
                     )
                 ) {
                     builder.startObject();
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/FileRestoreContext.java b/server/src/main/java/org/opensearch/repositories/blobstore/FileRestoreContext.java
index 28c75e51dc407..7e6e3a0ad3b79 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/FileRestoreContext.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/FileRestoreContext.java
@@ -34,15 +34,16 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.util.iterable.Iterables;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardRestoreFailedException;
 import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
 import org.opensearch.index.snapshots.blobstore.SnapshotFiles;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.remote.directory.RemoteSnapshotDirectory;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.snapshots.SnapshotId;
 
@@ -61,6 +62,8 @@
  * restore from some form of a snapshot. It will setup a new store, identify files that need to be copied
  * for the source, and perform the copies. Implementers must implement the functionality of opening the
  * underlying file streams for snapshotted lucene file.
+ *
+ * @opensearch.internal
  */
 public abstract class FileRestoreContext {
 
@@ -196,6 +199,10 @@ public void restore(SnapshotFiles snapshotFiles, Store store, ActionListener<Voi
     }
 
     private void afterRestore(SnapshotFiles snapshotFiles, Store store, StoreFileMetadata restoredSegmentsFile) {
+        // no cleanup needed for searchable snapshots
+        if (store.directory() instanceof RemoteSnapshotDirectory) {
+            return;
+        }
         // read the snapshot data persisted
         try {
             Lucene.pruneUnreferencedFiles(restoredSegmentsFile.name(), store.directory());
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/MeteredBlobStoreRepository.java b/server/src/main/java/org/opensearch/repositories/blobstore/MeteredBlobStoreRepository.java
index a3ebda3982aa9..d4921f4e6d2e7 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/MeteredBlobStoreRepository.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/MeteredBlobStoreRepository.java
@@ -35,7 +35,7 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.RepositoryInfo;
 import org.opensearch.repositories.RepositoryStatsSnapshot;
@@ -43,18 +43,22 @@
 
 import java.util.Map;
 
+/**
+ * A blob store repository that is metered
+ *
+ * @opensearch.internal
+ */
 public abstract class MeteredBlobStoreRepository extends BlobStoreRepository {
     private final RepositoryInfo repositoryInfo;
 
     public MeteredBlobStoreRepository(
         RepositoryMetadata metadata,
-        boolean compress,
         NamedXContentRegistry namedXContentRegistry,
         ClusterService clusterService,
         RecoverySettings recoverySettings,
         Map<String, String> location
     ) {
-        super(metadata, compress, namedXContentRegistry, clusterService, recoverySettings);
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings);
         ThreadPool threadPool = clusterService.getClusterApplierService().threadPool();
         this.repositoryInfo = new RepositoryInfo(
             UUIDs.randomBase64UUID(),
@@ -65,6 +69,14 @@ public MeteredBlobStoreRepository(
         );
     }
 
+    @Override
+    public void reload(RepositoryMetadata repositoryMetadata) {
+        super.reload(repositoryMetadata);
+
+        // Not adding any additional reload logic here is intentional as the constructor only
+        // initializes the repositoryInfo from the repo metadata, which cannot be changed.
+    }
+
     public RepositoryStatsSnapshot statsSnapshot() {
         return new RepositoryStatsSnapshot(repositoryInfo, stats(), RepositoryStatsSnapshot.UNKNOWN_CLUSTER_VERSION, false);
     }
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/package-info.java b/server/src/main/java/org/opensearch/repositories/blobstore/package-info.java
index 92ae4b69c45bc..aacd386cd4bd7 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/package-info.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/package-info.java
@@ -38,8 +38,8 @@
  * any {@code BlobStoreRepository} implementation must provide via its implementation of
  * {@link org.opensearch.repositories.blobstore.BlobStoreRepository#getBlobContainer()}.</p>
  *
- * <p>The blob store is written to and read from by master-eligible nodes and data nodes. All metadata related to a snapshot's
- * scope and health is written by the master node.</p>
+ * <p>The blob store is written to and read from by cluster-manager-eligible nodes and data nodes. All metadata related to a snapshot's
+ * scope and health is written by the cluster-manager node.</p>
  * <p>The data-nodes on the other hand, write the data for each individual shard but do not write any blobs outside of shard directories for
  * shards that they hold the primary of. For each shard, the data-node holding the shard's primary writes the actual data in form of
  * the shard's segment files to the repository as well as metadata about all the segment files that the repository stores for the shard.</p>
@@ -131,19 +131,19 @@
  * <h2>Writing Updated RepositoryData to the Repository</h2>
  *
  * <p>Writing an updated {@link org.opensearch.repositories.RepositoryData} to a blob store repository is an operation that uses
- * the cluster state to ensure that a specific {@code index-N} blob is never accidentally overwritten in a master failover scenario.
+ * the cluster state to ensure that a specific {@code index-N} blob is never accidentally overwritten in a cluster-manager failover scenario.
  * The specific steps to writing a new {@code index-N} blob and thus making changes from a snapshot-create or delete operation visible
- * to read operations on the repository are as follows and all run on the master node:</p>
+ * to read operations on the repository are as follows and all run on the cluster-manager node:</p>
  *
  * <ol>
  * <li>Write an updated value of {@link org.opensearch.cluster.metadata.RepositoryMetadata} for the repository that has the same
  * {@link org.opensearch.cluster.metadata.RepositoryMetadata#generation()} as the existing entry and has a value of
  * {@link org.opensearch.cluster.metadata.RepositoryMetadata#pendingGeneration()} one greater than the {@code pendingGeneration} of the
  * existing entry.</li>
- * <li>On the same master node, after the cluster state has been updated in the first step, write the new {@code index-N} blob and
+ * <li>On the same cluster-manager node, after the cluster state has been updated in the first step, write the new {@code index-N} blob and
  * also update the contents of the {@code index.latest} blob. Note that updating the index.latest blob is done on a best effort
- * basis and that there is a chance for a stuck master-node to overwrite the contents of the {@code index.latest} blob after a newer
- * {@code index-N} has been written by another master node. This is acceptable since the contents of {@code index.latest} are not used
+ * basis and that there is a chance for a stuck cluster-manager node to overwrite the contents of the {@code index.latest} blob after a newer
+ * {@code index-N} has been written by another cluster-manager node. This is acceptable since the contents of {@code index.latest} are not used
  * during normal operation of the repository and must only be correct for purposes of mounting the contents of a
  * {@link org.opensearch.repositories.blobstore.BlobStoreRepository} as a read-only url repository.</li>
  * <li>After the write has finished, set the value of {@code RepositoriesState.State#generation} to the value used for
@@ -152,7 +152,7 @@
  * last valid {@code index-N} blob in the repository.</li>
  * </ol>
  *
- * <p>If either of the last two steps in the above fails or master fails over to a new node at any point, then a subsequent operation
+ * <p>If either of the last two steps in the above fails or cluster-manager fails over to a new node at any point, then a subsequent operation
  * trying to write a new {@code index-N} blob will never use the same value of {@code N} used by a previous attempt. It will always start
  * over at the first of the above three steps, incrementing the {@code pendingGeneration} generation before attempting a write, thus
  * ensuring no overwriting of a {@code index-N} blob ever to occur. The use of the cluster state to track the latest repository generation
@@ -208,7 +208,7 @@
  *
  * <h3>Finalizing the Snapshot</h3>
  *
- * <p>After all primaries have finished writing the necessary segment files to the blob store in the previous step, the master node moves on
+ * <p>After all primaries have finished writing the necessary segment files to the blob store in the previous step, the cluster-manager node moves on
  * to finalizing the snapshot by invoking {@link org.opensearch.repositories.Repository#finalizeSnapshot}. This method executes the
  * following actions in order:</p>
  * <ol>
@@ -222,7 +222,7 @@
  *
  * <h2>Deleting a Snapshot</h2>
  *
- * <p>Deleting a snapshot is an operation that is exclusively executed on the master node that runs through the following sequence of
+ * <p>Deleting a snapshot is an operation that is exclusively executed on the cluster-manager node that runs through the following sequence of
  * action when {@link org.opensearch.repositories.blobstore.BlobStoreRepository#deleteSnapshots} is invoked:</p>
  *
  * <ol>
diff --git a/server/src/main/java/org/opensearch/repositories/fs/FsRepository.java b/server/src/main/java/org/opensearch/repositories/fs/FsRepository.java
index e57246265bb66..4a9a91336ec1d 100644
--- a/server/src/main/java/org/opensearch/repositories/fs/FsRepository.java
+++ b/server/src/main/java/org/opensearch/repositories/fs/FsRepository.java
@@ -41,14 +41,17 @@
 import org.opensearch.common.blobstore.fs.FsBlobStore;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.RepositoryException;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.function.Function;
 
 /**
@@ -60,8 +63,9 @@
  * <dt>{@code concurrent_streams}</dt><dd>Number of concurrent read/write stream (per repository on each node). Defaults to 5.</dd>
  * <dt>{@code chunk_size}</dt><dd>Large file can be divided into chunks. This parameter specifies the chunk size.
  *      Defaults to not chucked.</dd>
- * <dt>{@code compress}</dt><dd>If set to true metadata files will be stored compressed. Defaults to false.</dd>
  * </dl>
+ *
+ * @opensearch.internal
  */
 public class FsRepository extends BlobStoreRepository {
     private static final Logger logger = LogManager.getLogger(FsRepository.class);
@@ -89,18 +93,20 @@ public class FsRepository extends BlobStoreRepository {
         new ByteSizeValue(Long.MAX_VALUE),
         Property.NodeScope
     );
-    public static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", false, Property.NodeScope);
     public static final Setting<Boolean> REPOSITORIES_COMPRESS_SETTING = Setting.boolSetting(
         "repositories.fs.compress",
         false,
         Property.NodeScope,
         Property.Deprecated
     );
-    private final Environment environment;
 
-    private ByteSizeValue chunkSize;
+    public static final Setting<String> BASE_PATH_SETTING = Setting.simpleString("base_path");
+
+    protected final Environment environment;
 
-    private final BlobPath basePath;
+    protected ByteSizeValue chunkSize;
+
+    protected BlobPath basePath;
 
     /**
      * Constructs a shared file system repository.
@@ -112,13 +118,32 @@ public FsRepository(
         ClusterService clusterService,
         RecoverySettings recoverySettings
     ) {
-        super(metadata, calculateCompress(metadata, environment), namedXContentRegistry, clusterService, recoverySettings);
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings);
         this.environment = environment;
+        validateLocation();
+        readMetadata();
+    }
+
+    protected void readMetadata() {
+        if (CHUNK_SIZE_SETTING.exists(metadata.settings())) {
+            this.chunkSize = CHUNK_SIZE_SETTING.get(metadata.settings());
+        } else {
+            this.chunkSize = REPOSITORIES_CHUNK_SIZE_SETTING.get(environment.settings());
+        }
+        final String basePath = BASE_PATH_SETTING.get(metadata.settings());
+        if (Strings.hasLength(basePath)) {
+            this.basePath = new BlobPath().add(basePath);
+        } else {
+            this.basePath = BlobPath.cleanPath();
+        }
+    }
+
+    protected void validateLocation() {
         String location = REPOSITORIES_LOCATION_SETTING.get(metadata.settings());
         if (location.isEmpty()) {
             logger.warn(
                 "the repository location is missing, it should point to a shared file system location"
-                    + " that is available on all master and data nodes"
+                    + " that is available on all cluster-manager and data nodes"
             );
             throw new RepositoryException(metadata.name(), "missing location");
         }
@@ -146,19 +171,6 @@ public FsRepository(
                 );
             }
         }
-
-        if (CHUNK_SIZE_SETTING.exists(metadata.settings())) {
-            this.chunkSize = CHUNK_SIZE_SETTING.get(metadata.settings());
-        } else {
-            this.chunkSize = REPOSITORIES_CHUNK_SIZE_SETTING.get(environment.settings());
-        }
-        this.basePath = BlobPath.cleanPath();
-    }
-
-    private static boolean calculateCompress(RepositoryMetadata metadata, Environment environment) {
-        return COMPRESS_SETTING.exists(metadata.settings())
-            ? COMPRESS_SETTING.get(metadata.settings())
-            : REPOSITORIES_COMPRESS_SETTING.get(environment.settings());
     }
 
     @Override
@@ -177,4 +189,12 @@ protected ByteSizeValue chunkSize() {
     public BlobPath basePath() {
         return basePath;
     }
+
+    @Override
+    public List<Setting<?>> getRestrictedSystemRepositorySettings() {
+        List<Setting<?>> restrictedSettings = new ArrayList<>();
+        restrictedSettings.addAll(super.getRestrictedSystemRepositorySettings());
+        restrictedSettings.add(LOCATION_SETTING);
+        return restrictedSettings;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/repositories/fs/ReloadableFsRepository.java b/server/src/main/java/org/opensearch/repositories/fs/ReloadableFsRepository.java
new file mode 100644
index 0000000000000..c06c805a39396
--- /dev/null
+++ b/server/src/main/java/org/opensearch/repositories/fs/ReloadableFsRepository.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.fs;
+
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.indices.recovery.RecoverySettings;
+
+/**
+ * Extension of {@link FsRepository} that can be reloaded inplace
+ *
+ * @opensearch.internal
+ */
+public class ReloadableFsRepository extends FsRepository {
+    /**
+     * Constructs a shared file system repository that is reloadable in-place.
+     */
+    public ReloadableFsRepository(
+        RepositoryMetadata metadata,
+        Environment environment,
+        NamedXContentRegistry namedXContentRegistry,
+        ClusterService clusterService,
+        RecoverySettings recoverySettings
+    ) {
+        super(metadata, environment, namedXContentRegistry, clusterService, recoverySettings);
+    }
+
+    @Override
+    public boolean isReloadable() {
+        return true;
+    }
+
+    @Override
+    public void reload(RepositoryMetadata repositoryMetadata) {
+        if (isReloadable() == false) {
+            return;
+        }
+
+        super.reload(repositoryMetadata);
+        validateLocation();
+        readMetadata();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/repositories/fs/package-info.java b/server/src/main/java/org/opensearch/repositories/fs/package-info.java
new file mode 100644
index 0000000000000..2f3f9aedad933
--- /dev/null
+++ b/server/src/main/java/org/opensearch/repositories/fs/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** FileSystem snapshot repository store package. */
+package org.opensearch.repositories.fs;
diff --git a/server/src/main/java/org/opensearch/rest/AbstractRestChannel.java b/server/src/main/java/org/opensearch/rest/AbstractRestChannel.java
index 536972aa5a5d7..11a116e8c858d 100644
--- a/server/src/main/java/org/opensearch/rest/AbstractRestChannel.java
+++ b/server/src/main/java/org/opensearch/rest/AbstractRestChannel.java
@@ -32,12 +32,12 @@
 package org.opensearch.rest;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -47,6 +47,11 @@
 
 import static java.util.stream.Collectors.toSet;
 
+/**
+ * Base REST channel
+ *
+ * @opensearch.api
+ */
 public abstract class AbstractRestChannel implements RestChannel {
 
     private static final Predicate<String> INCLUDE_FILTER = f -> f.charAt(0) != '-';
@@ -58,6 +63,7 @@ public abstract class AbstractRestChannel implements RestChannel {
     private final String filterPath;
     private final boolean pretty;
     private final boolean human;
+    private final String acceptHeader;
 
     private BytesStreamOutput bytesOut;
 
@@ -71,7 +77,8 @@ public abstract class AbstractRestChannel implements RestChannel {
     protected AbstractRestChannel(RestRequest request, boolean detailedErrorsEnabled) {
         this.request = request;
         this.detailedErrorsEnabled = detailedErrorsEnabled;
-        this.format = request.param("format", request.header("Accept"));
+        this.format = request.param("format");
+        this.acceptHeader = request.header("Accept");
         this.filterPath = request.param("filter_path", null);
         this.pretty = request.paramAsBoolean("pretty", false);
         this.human = request.paramAsBoolean("human", false);
@@ -79,40 +86,41 @@ protected AbstractRestChannel(RestRequest request, boolean detailedErrorsEnabled
 
     @Override
     public XContentBuilder newBuilder() throws IOException {
-        return newBuilder(request.getXContentType(), true);
+        return newBuilder(request.getMediaType(), true);
     }
 
     @Override
     public XContentBuilder newErrorBuilder() throws IOException {
         // Disable filtering when building error responses
-        return newBuilder(request.getXContentType(), false);
+        return newBuilder(request.getMediaType(), false);
     }
 
     /**
      * Creates a new {@link XContentBuilder} for a response to be sent using this channel. The builder's type is determined by the following
-     * logic. If the request has a format parameter that will be used to attempt to map to an {@link XContentType}. If there is no format
-     * parameter, the HTTP Accept header is checked to see if it can be matched to a {@link XContentType}. If this first attempt to map
+     * logic. If the request has a format parameter that will be used to attempt to map to an {@link MediaType}. If there is no format
+     * parameter, the HTTP Accept header is checked to see if it can be matched to a {@link MediaType}. If this first attempt to map
      * fails, the request content type will be used if the value is not {@code null}; if the value is {@code null} the output format falls
      * back to JSON.
      */
     @Override
-    public XContentBuilder newBuilder(@Nullable XContentType requestContentType, boolean useFiltering) throws IOException {
+    public XContentBuilder newBuilder(@Nullable MediaType requestContentType, boolean useFiltering) throws IOException {
         return newBuilder(requestContentType, null, useFiltering);
     }
 
     /**
      * Creates a new {@link XContentBuilder} for a response to be sent using this channel. The builder's type can be sent as a parameter,
-     * through {@code responseContentType} or it can fallback to {@link #newBuilder(XContentType, boolean)} logic if the sent type value
+     * through {@code responseContentType} or it can fallback to {@link #newBuilder(MediaType, boolean)} logic if the sent type value
      * is {@code null}.
      */
     @Override
-    public XContentBuilder newBuilder(
-        @Nullable XContentType requestContentType,
-        @Nullable XContentType responseContentType,
-        boolean useFiltering
-    ) throws IOException {
+    public XContentBuilder newBuilder(@Nullable MediaType requestContentType, @Nullable MediaType responseContentType, boolean useFiltering)
+        throws IOException {
         if (responseContentType == null) {
-            responseContentType = XContentType.fromMediaTypeOrFormat(format);
+            // TODO should format vs acceptHeader always be the same, do we allow overriding?
+            responseContentType = MediaType.fromFormat(format);
+            if (responseContentType == null) {
+                responseContentType = MediaType.fromMediaType(acceptHeader);
+            }
         }
         // try to determine the response content type from the media type or the format query string parameter, with the format parameter
         // taking precedence over the Accept header
@@ -123,7 +131,7 @@ public XContentBuilder newBuilder(
                 responseContentType = requestContentType;
             } else {
                 // default to JSON output when all else fails
-                responseContentType = XContentType.JSON;
+                responseContentType = MediaTypeRegistry.getDefaultMediaType();
             }
         }
 
@@ -136,12 +144,7 @@ public XContentBuilder newBuilder(
         }
 
         OutputStream unclosableOutputStream = Streams.flushOnCloseStream(bytesOutput());
-        XContentBuilder builder = new XContentBuilder(
-            XContentFactory.xContent(responseContentType),
-            unclosableOutputStream,
-            includes,
-            excludes
-        );
+        XContentBuilder builder = new XContentBuilder(responseContentType.xContent(), unclosableOutputStream, includes, excludes);
         if (pretty) {
             builder.prettyPrint().lfAtEnd();
         }
diff --git a/server/src/main/java/org/opensearch/rest/BaseRestHandler.java b/server/src/main/java/org/opensearch/rest/BaseRestHandler.java
index 4ee209111bdcb..58fa989b0b760 100644
--- a/server/src/main/java/org/opensearch/rest/BaseRestHandler.java
+++ b/server/src/main/java/org/opensearch/rest/BaseRestHandler.java
@@ -36,13 +36,18 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.spell.LevenshteinDistance;
 import org.apache.lucene.util.CollectionUtil;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.rest.action.admin.cluster.RestNodesUsageAction;
+import org.opensearch.tasks.Task;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -64,6 +69,8 @@
  * the transport requests executed by the associated client. While the context is fully copied over, not all the headers
  * are copied, but a selected few. It is possible to control what headers are copied over by returning them in
  * {@link ActionPlugin#getRestHeaders()}.
+ *
+ * @opensearch.api
  */
 public abstract class BaseRestHandler implements RestHandler {
 
@@ -121,7 +128,7 @@ public final void handleRequest(RestRequest request, RestChannel channel, NodeCl
         action.accept(channel);
     }
 
-    protected final String unrecognized(
+    public static String unrecognizedStrings(
         final RestRequest request,
         final Set<String> invalids,
         final Set<String> candidates,
@@ -166,6 +173,24 @@ protected final String unrecognized(
         return message.toString();
     }
 
+    /**
+     * Returns a String message of the detail of any unrecognized error occurred. The string is intended for use in error messages to be returned to the user.
+     *
+     * @param request The request that caused the exception
+     * @param invalids Strings from the request which were unable to be understood.
+     * @param candidates A set of words that are most likely to be the valid strings determined invalid, to be suggested to the user.
+     * @param detail The parameter contains the details of the exception.
+     * @return a String that contains the message.
+     */
+    protected final String unrecognized(
+        final RestRequest request,
+        final Set<String> invalids,
+        final Set<String> candidates,
+        final String detail
+    ) {
+        return unrecognizedStrings(request, invalids, candidates, detail);
+    }
+
     /**
      * REST requests are handled by preparing a channel consumer that represents the execution of
      * the request against a channel.
@@ -200,6 +225,31 @@ protected Set<String> responseParams() {
         return Collections.emptySet();
     }
 
+    protected static final String DUPLICATE_PARAMETER_ERROR_MESSAGE =
+        "Please only use one of the request parameters [master_timeout, cluster_manager_timeout].";
+
+    /**
+     * Parse the deprecated request parameter 'master_timeout', and add deprecated log if the parameter is used.
+     * It also validates whether the two parameters 'master_timeout' and 'cluster_manager_timeout' are not assigned together.
+     * Deprecation log is not emitted intentionally, because 'master_timeout' is remained in High-Level-REST-Client to keep compatibility with server 1.x.
+     * The method is temporarily added in 2.0 during applying inclusive language. Remove the method along with the parameter 'master_timeout'.
+     * @param mnr the action request
+     * @param request the REST request to handle
+     */
+    public static void parseDeprecatedMasterTimeoutParameter(ClusterManagerNodeRequest mnr, RestRequest request) {
+        if (request.hasParam("master_timeout")) {
+            if (request.hasParam("cluster_manager_timeout")) {
+                throw new OpenSearchParseException(DUPLICATE_PARAMETER_ERROR_MESSAGE);
+            }
+            mnr.clusterManagerNodeTimeout(request.paramAsTime("master_timeout", mnr.clusterManagerNodeTimeout()));
+        }
+    }
+
+    /**
+     * A wrapper for the base handler.
+     *
+     * @opensearch.internal
+     */
     public static class Wrapper extends BaseRestHandler {
 
         protected final BaseRestHandler delegate;
@@ -258,4 +308,18 @@ public boolean allowSystemIndexAccessByDefault() {
             return delegate.allowSystemIndexAccessByDefault();
         }
     }
+
+    /**
+     * Return a task immediately when executing some long-running operations asynchronously, like reindex, resize, open, force merge
+     */
+    public RestChannelConsumer sendTask(String nodeId, Task task) {
+        return channel -> {
+            try (XContentBuilder builder = channel.newBuilder()) {
+                builder.startObject();
+                builder.field("task", nodeId + ":" + task.getId());
+                builder.endObject();
+                channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
+            }
+        };
+    }
 }
diff --git a/server/src/main/java/org/opensearch/rest/BytesRestResponse.java b/server/src/main/java/org/opensearch/rest/BytesRestResponse.java
index 7d2b49f3f0171..c8a4e566e8e4d 100644
--- a/server/src/main/java/org/opensearch/rest/BytesRestResponse.java
+++ b/server/src/main/java/org/opensearch/rest/BytesRestResponse.java
@@ -36,22 +36,26 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchStatusException;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
 import static java.util.Collections.singletonMap;
-import static org.opensearch.OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE;
-import static org.opensearch.OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * REST response in bytes
+ *
+ * @opensearch.api
+ */
 public class BytesRestResponse extends RestResponse {
 
     public static final String TEXT_CONTENT_TYPE = "text/plain; charset=UTF-8";
@@ -107,7 +111,10 @@ public BytesRestResponse(RestChannel channel, Exception e) throws IOException {
 
     public BytesRestResponse(RestChannel channel, RestStatus status, Exception e) throws IOException {
         ToXContent.Params params = paramsFromRequest(channel.request());
-        if (params.paramAsBoolean(REST_EXCEPTION_SKIP_STACK_TRACE, REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT) && e != null) {
+        if (params.paramAsBoolean(
+            OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE,
+            OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT
+        ) && e != null) {
             // log exception only if it is not returned in the response
             Supplier<?> messageSupplier = () -> new ParameterizedMessage(
                 "path: {}, params: {}",
@@ -148,8 +155,9 @@ public RestStatus status() {
 
     private ToXContent.Params paramsFromRequest(RestRequest restRequest) {
         ToXContent.Params params = restRequest;
-        if (params.paramAsBoolean("error_trace", !REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT) && false == skipStackTrace()) {
-            params = new ToXContent.DelegatingMapParams(singletonMap(REST_EXCEPTION_SKIP_STACK_TRACE, "false"), params);
+        if (params.paramAsBoolean("error_trace", OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE_DEFAULT == false)
+            && false == skipStackTrace()) {
+            params = new ToXContent.DelegatingMapParams(singletonMap(OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE, "false"), params);
         }
         return params;
     }
diff --git a/server/src/main/java/org/opensearch/rest/DeprecationRestHandler.java b/server/src/main/java/org/opensearch/rest/DeprecationRestHandler.java
index 85a7f0f0281c5..0cdb08a11b45e 100644
--- a/server/src/main/java/org/opensearch/rest/DeprecationRestHandler.java
+++ b/server/src/main/java/org/opensearch/rest/DeprecationRestHandler.java
@@ -32,14 +32,16 @@
 package org.opensearch.rest;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 
 import java.util.Objects;
 
 /**
  * {@code DeprecationRestHandler} provides a proxy for any existing {@link RestHandler} so that usage of the handler can be
  * logged using the {@link DeprecationLogger}.
+ *
+ * @opensearch.api
  */
 public class DeprecationRestHandler implements RestHandler {
 
diff --git a/server/src/main/java/org/opensearch/rest/MethodHandlers.java b/server/src/main/java/org/opensearch/rest/MethodHandlers.java
index d8f5488dc2ee3..8c29bf2e66036 100644
--- a/server/src/main/java/org/opensearch/rest/MethodHandlers.java
+++ b/server/src/main/java/org/opensearch/rest/MethodHandlers.java
@@ -40,6 +40,8 @@
 
 /**
  * Encapsulate multiple handlers for the same path, allowing different handlers for different HTTP verbs.
+ *
+ * @opensearch.api
  */
 final class MethodHandlers {
 
diff --git a/server/src/main/java/org/opensearch/rest/NamedRoute.java b/server/src/main/java/org/opensearch/rest/NamedRoute.java
new file mode 100644
index 0000000000000..109f688a4924e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/NamedRoute.java
@@ -0,0 +1,189 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.transport.TransportService;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.function.Function;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * A named Route
+ *
+ * @opensearch.internal
+ */
+public class NamedRoute extends RestHandler.Route {
+
+    private static final String VALID_ACTION_NAME_PATTERN = "^[a-zA-Z0-9:/*_]*$";
+    static final int MAX_LENGTH_OF_ACTION_NAME = 250;
+
+    private final String uniqueName;
+    private final Set<String> actionNames;
+
+    private Function<RestRequest, RestResponse> handler;
+
+    /**
+     * Builder class for constructing instances of {@link NamedRoute}.
+     */
+    public static class Builder {
+        private RestRequest.Method method;
+        private String path;
+        private String uniqueName;
+        private final Set<String> legacyActionNames = new HashSet<>();
+        private Function<RestRequest, RestResponse> handler;
+
+        /**
+         * Sets the REST method for the route.
+         *
+         * @param method the REST method for the route
+         * @return the builder instance
+         */
+        public Builder method(RestRequest.Method method) {
+            requireNonNull(method, "REST method must not be null.");
+            this.method = method;
+            return this;
+        }
+
+        /**
+         * Sets the URL path for the route.
+         *
+         * @param path the URL path for the route
+         * @return the builder instance
+         */
+        public Builder path(String path) {
+            requireNonNull(path, "REST path must not be null.");
+            this.path = path;
+            return this;
+        }
+
+        /**
+         * Sets the name for the route.
+         *
+         * @param name the name for the route
+         * @return the builder instance
+         */
+        public Builder uniqueName(String name) {
+            requireNonNull(name, "REST route name must not be null.");
+            this.uniqueName = name;
+            return this;
+        }
+
+        /**
+         * Sets the legacy action names for the route.
+         *
+         * @param legacyActionNames the legacy action names for the route
+         * @return the builder instance
+         */
+        public Builder legacyActionNames(Set<String> legacyActionNames) {
+            this.legacyActionNames.addAll(validateLegacyActionNames(legacyActionNames));
+            return this;
+        }
+
+        /**
+         * Sets the handler for this route
+         *
+         * @param handler the handler for this route
+         * @return the builder instance
+         */
+        public Builder handler(Function<RestRequest, RestResponse> handler) {
+            requireNonNull(handler, "Route handler must not be null.");
+            this.handler = handler;
+            return this;
+        }
+
+        /**
+         * Builds a new instance of {@link NamedRoute} based on the provided parameters.
+         *
+         * @return a new instance of {@link NamedRoute}
+         * @throws OpenSearchException if the route name is invalid
+         */
+        public NamedRoute build() {
+            checkIfFieldsAreSet();
+            return new NamedRoute(this);
+        }
+
+        /**
+         * Checks if all builder fields are set before creating a new NamedRoute object
+         */
+        private void checkIfFieldsAreSet() {
+            if (method == null || path == null || uniqueName == null) {
+                throw new IllegalStateException("REST method, path and uniqueName are required.");
+            }
+        }
+
+        private Set<String> validateLegacyActionNames(Set<String> legacyActionNames) {
+            if (legacyActionNames == null) {
+                return new HashSet<>();
+            }
+            for (String actionName : legacyActionNames) {
+                if (!TransportService.isValidActionName(actionName)) {
+                    throw new OpenSearchException(
+                        "Invalid action name [" + actionName + "]. It must start with one of: " + TransportService.VALID_ACTION_PREFIXES
+                    );
+                }
+            }
+            return legacyActionNames;
+        }
+
+    }
+
+    private NamedRoute(Builder builder) {
+        super(builder.method, builder.path);
+        if (!isValidRouteName(builder.uniqueName)) {
+            throw new OpenSearchException(
+                "Invalid route name specified. The route name may include the following characters"
+                    + " 'a-z', 'A-Z', '0-9', ':', '/', '*', '_' and be less than "
+                    + MAX_LENGTH_OF_ACTION_NAME
+                    + " characters"
+            );
+        }
+        this.uniqueName = builder.uniqueName;
+        this.actionNames = Set.copyOf(builder.legacyActionNames);
+        this.handler = builder.handler;
+    }
+
+    public boolean isValidRouteName(String routeName) {
+        return routeName != null
+            && !routeName.isBlank()
+            && routeName.length() <= MAX_LENGTH_OF_ACTION_NAME
+            && routeName.matches(VALID_ACTION_NAME_PATTERN);
+    }
+
+    /**
+     * The name of the Route. Must be unique across Route.
+     */
+    public String name() {
+        return this.uniqueName;
+    }
+
+    /**
+     * The legacy transport Action name to match against this route to support authorization in REST layer.
+     * MUST be unique across all Routes
+     */
+    public Set<String> actionNames() {
+        return this.actionNames;
+    }
+
+    /**
+     * The handler associated with this route
+     * @return the handler associated with this route
+     */
+    public Function<RestRequest, RestResponse> handler() {
+        return handler;
+    }
+
+    @Override
+    public String toString() {
+        return "NamedRoute [method=" + method + ", path=" + path + ", name=" + uniqueName + ", actionNames=" + actionNames + "]";
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/RestChannel.java b/server/src/main/java/org/opensearch/rest/RestChannel.java
index e3108b6ca4b20..b8ce3e92e0098 100644
--- a/server/src/main/java/org/opensearch/rest/RestChannel.java
+++ b/server/src/main/java/org/opensearch/rest/RestChannel.java
@@ -34,13 +34,15 @@
 
 import org.opensearch.common.Nullable;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
 /**
  * A channel used to construct bytes / builder based outputs, and send responses.
+ *
+ * @opensearch.api
  */
 public interface RestChannel {
 
@@ -48,9 +50,9 @@ public interface RestChannel {
 
     XContentBuilder newErrorBuilder() throws IOException;
 
-    XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException;
+    XContentBuilder newBuilder(@Nullable MediaType mediaType, boolean useFiltering) throws IOException;
 
-    XContentBuilder newBuilder(@Nullable XContentType xContentType, @Nullable XContentType responseContentType, boolean useFiltering)
+    XContentBuilder newBuilder(@Nullable MediaType mediaType, @Nullable MediaType responseContentType, boolean useFiltering)
         throws IOException;
 
     BytesStreamOutput bytesOutput();
diff --git a/server/src/main/java/org/opensearch/rest/RestController.java b/server/src/main/java/org/opensearch/rest/RestController.java
index f2030eb83a581..ac30f999d0da7 100644
--- a/server/src/main/java/org/opensearch/rest/RestController.java
+++ b/server/src/main/java/org/opensearch/rest/RestController.java
@@ -38,24 +38,33 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.path.PathTrie;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.io.Streams;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.http.HttpServerTransport;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.identity.Subject;
+import org.opensearch.identity.tokens.AuthToken;
+import org.opensearch.identity.tokens.RestTokenExtractor;
 import org.opensearch.usage.UsageService;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.net.URI;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -68,13 +77,18 @@
 import java.util.stream.Collectors;
 
 import static org.opensearch.cluster.metadata.IndexNameExpressionResolver.SYSTEM_INDEX_ACCESS_CONTROL_HEADER_KEY;
+import static org.opensearch.core.rest.RestStatus.BAD_REQUEST;
+import static org.opensearch.core.rest.RestStatus.INTERNAL_SERVER_ERROR;
+import static org.opensearch.core.rest.RestStatus.METHOD_NOT_ALLOWED;
+import static org.opensearch.core.rest.RestStatus.NOT_ACCEPTABLE;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.BytesRestResponse.TEXT_CONTENT_TYPE;
-import static org.opensearch.rest.RestStatus.BAD_REQUEST;
-import static org.opensearch.rest.RestStatus.INTERNAL_SERVER_ERROR;
-import static org.opensearch.rest.RestStatus.METHOD_NOT_ALLOWED;
-import static org.opensearch.rest.RestStatus.NOT_ACCEPTABLE;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * OpenSearch REST controller
+ *
+ * @opensearch.api
+ */
 public class RestController implements HttpServerTransport.Dispatcher {
 
     private static final Logger logger = LogManager.getLogger(RestController.class);
@@ -104,13 +118,15 @@ public class RestController implements HttpServerTransport.Dispatcher {
     /** Rest headers that are copied to internal requests made during a rest request. */
     private final Set<RestHeaderDefinition> headersToCopy;
     private final UsageService usageService;
+    private final IdentityService identityService;
 
     public RestController(
         Set<RestHeaderDefinition> headersToCopy,
         UnaryOperator<RestHandler> handlerWrapper,
         NodeClient client,
         CircuitBreakerService circuitBreakerService,
-        UsageService usageService
+        UsageService usageService,
+        IdentityService identityService
     ) {
         this.headersToCopy = headersToCopy;
         this.usageService = usageService;
@@ -120,6 +136,7 @@ public RestController(
         this.handlerWrapper = handlerWrapper;
         this.client = client;
         this.circuitBreakerService = circuitBreakerService;
+        this.identityService = identityService;
         registerHandlerNoWrap(
             RestRequest.Method.GET,
             "/favicon.ico",
@@ -267,17 +284,17 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
     private void dispatchRequest(RestRequest request, RestChannel channel, RestHandler handler) throws Exception {
         final int contentLength = request.content().length();
         if (contentLength > 0) {
-            final XContentType xContentType = request.getXContentType();
-            if (xContentType == null) {
+            final MediaType mediaType = request.getMediaType();
+            if (mediaType == null) {
                 sendContentTypeErrorMessage(request.getAllHeaderValues("Content-Type"), channel);
                 return;
             }
-            if (handler.supportsContentStream() && xContentType != XContentType.JSON && xContentType != XContentType.SMILE) {
+            if (handler.supportsContentStream() && mediaType != MediaTypeRegistry.JSON && mediaType != XContentType.SMILE) {
                 channel.sendResponse(
                     BytesRestResponse.createSimpleErrorResponse(
                         channel,
                         RestStatus.NOT_ACCEPTABLE,
-                        "Content-Type [" + xContentType + "] does not support stream parsing. Use JSON or SMILE instead"
+                        "Content-Type [" + mediaType + "] does not support stream parsing. Use JSON or SMILE instead"
                     )
                 );
                 return;
@@ -389,6 +406,11 @@ private void tryAllHandlers(final RestRequest request, final RestChannel channel
                         return;
                     }
                 } else {
+                    if (FeatureFlags.isEnabled(FeatureFlags.IDENTITY)) {
+                        if (!handleAuthenticateUser(request, channel)) {
+                            return;
+                        }
+                    }
                     dispatchRequest(request, channel, handler);
                     return;
                 }
@@ -442,7 +464,9 @@ private void handleUnsupportedHttpMethod(
                 msg.append("Incorrect HTTP method for uri [").append(uri);
                 msg.append("] and method [").append(method).append("]");
             } else {
-                msg.append(exception.getMessage());
+                // Not using the error message directly from 'exception.getMessage()' to avoid unescaped HTML special characters,
+                // in case false-positive cross site scripting vulnerability is detected by common security scanners.
+                msg.append("Unexpected HTTP method");
             }
             if (validMethodSet.isEmpty() == false) {
                 msg.append(", allowed: ").append(validMethodSet);
@@ -483,13 +507,55 @@ private void handleBadRequest(String uri, RestRequest.Method method, RestChannel
         try (XContentBuilder builder = channel.newErrorBuilder()) {
             builder.startObject();
             {
-                builder.field("error", "no handler found for uri [" + uri + "] and method [" + method + "]");
+                try {
+                    // Validate input URI to filter out HTML special characters in the error message,
+                    // in case false-positive cross site scripting vulnerability is detected by common security scanners.
+                    uri = new URI(uri).getPath();
+                    builder.field("error", "no handler found for uri [" + uri + "] and method [" + method + "]");
+                } catch (Exception e) {
+                    builder.field("error", "invalid uri has been requested");
+                }
             }
             builder.endObject();
             channel.sendResponse(new BytesRestResponse(BAD_REQUEST, builder));
         }
     }
 
+    /**
+     * Attempts to extract auth token and login.
+     *
+     * @returns false if there was an error and the request should not continue being dispatched
+     * */
+    private boolean handleAuthenticateUser(final RestRequest request, final RestChannel channel) {
+        try {
+            final AuthToken token = RestTokenExtractor.extractToken(request);
+            // If no token was found, continue executing the request
+            if (token == null) {
+                // Authentication did not fail so return true. Authorization is handled at the action level.
+                return true;
+            }
+            final Subject currentSubject = identityService.getSubject();
+            currentSubject.authenticate(token);
+            logger.debug("Logged in as user " + currentSubject);
+        } catch (final Exception e) {
+            try {
+                final BytesRestResponse bytesRestResponse = BytesRestResponse.createSimpleErrorResponse(
+                    channel,
+                    RestStatus.UNAUTHORIZED,
+                    e.getMessage()
+                );
+                channel.sendResponse(bytesRestResponse);
+            } catch (final Exception ex) {
+                final BytesRestResponse bytesRestResponse = new BytesRestResponse(RestStatus.UNAUTHORIZED, ex.getMessage());
+                channel.sendResponse(bytesRestResponse);
+            }
+            return false;
+        }
+
+        // Authentication did not fail so return true. Authorization is handled at the action level.
+        return true;
+    }
+
     /**
      * Get the valid set of HTTP methods for a REST request.
      */
@@ -528,14 +594,13 @@ public XContentBuilder newErrorBuilder() throws IOException {
         }
 
         @Override
-        public XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException {
-            return delegate.newBuilder(xContentType, useFiltering);
+        public XContentBuilder newBuilder(@Nullable MediaType mediaType, boolean useFiltering) throws IOException {
+            return delegate.newBuilder(mediaType, useFiltering);
         }
 
         @Override
-        public XContentBuilder newBuilder(XContentType xContentType, XContentType responseContentType, boolean useFiltering)
-            throws IOException {
-            return delegate.newBuilder(xContentType, responseContentType, useFiltering);
+        public XContentBuilder newBuilder(MediaType mediaType, MediaType responseContentType, boolean useFiltering) throws IOException {
+            return delegate.newBuilder(mediaType, responseContentType, useFiltering);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/rest/RestHandler.java b/server/src/main/java/org/opensearch/rest/RestHandler.java
index 9afa2d94b2044..7832649e8ad32 100644
--- a/server/src/main/java/org/opensearch/rest/RestHandler.java
+++ b/server/src/main/java/org/opensearch/rest/RestHandler.java
@@ -33,7 +33,7 @@
 package org.opensearch.rest;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContent;
+import org.opensearch.core.xcontent.XContent;
 import org.opensearch.rest.RestRequest.Method;
 
 import java.util.Collections;
@@ -43,6 +43,8 @@
 
 /**
  * Handler for REST requests
+ *
+ * @opensearch.api
  */
 @FunctionalInterface
 public interface RestHandler {
@@ -117,6 +119,11 @@ static RestHandler wrapper(RestHandler delegate) {
         return new Wrapper(delegate);
     }
 
+    /**
+     * Wrapper for a handler.
+     *
+     * @opensearch.internal
+     */
     class Wrapper implements RestHandler {
         private final RestHandler delegate;
 
@@ -170,10 +177,15 @@ public boolean allowSystemIndexAccessByDefault() {
         }
     }
 
+    /**
+     * Route for the request.
+     *
+     * @opensearch.internal
+     */
     class Route {
 
-        private final String path;
-        private final Method method;
+        protected final String path;
+        protected final Method method;
 
         public Route(Method method, String path) {
             this.path = path;
@@ -184,9 +196,37 @@ public String getPath() {
             return path;
         }
 
+        public String getPathWithPathParamsReplaced() {
+            return path.replaceAll("(?<=\\{).*?(?=\\})", "path_param");
+        }
+
         public Method getMethod() {
             return method;
         }
+
+        @Override
+        public int hashCode() {
+            String routeStr = "Route [method=" + method + ", path=" + getPathWithPathParamsReplaced() + "]";
+            return routeStr.hashCode();
+        }
+
+        @Override
+        public String toString() {
+            return "Route [method=" + method + ", path=" + path + "]";
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            Route that = (Route) o;
+            return Objects.equals(method, that.method)
+                && Objects.equals(getPathWithPathParamsReplaced(), that.getPathWithPathParamsReplaced());
+        }
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/rest/RestHeaderDefinition.java b/server/src/main/java/org/opensearch/rest/RestHeaderDefinition.java
index 7e7b851a42d6e..9bea8055077fe 100644
--- a/server/src/main/java/org/opensearch/rest/RestHeaderDefinition.java
+++ b/server/src/main/java/org/opensearch/rest/RestHeaderDefinition.java
@@ -35,6 +35,8 @@
 /**
  * A definition for an http header that should be copied to the {@link org.opensearch.common.util.concurrent.ThreadContext} when
  * reading the request on the rest layer.
+ *
+ * @opensearch.api
  */
 public final class RestHeaderDefinition {
     private final String name;
diff --git a/server/src/main/java/org/opensearch/rest/RestRequest.java b/server/src/main/java/org/opensearch/rest/RestRequest.java
index e04d8faa8af39..f64774686c89d 100644
--- a/server/src/main/java/org/opensearch/rest/RestRequest.java
+++ b/server/src/main/java/org/opensearch/rest/RestRequest.java
@@ -32,29 +32,28 @@
 
 package org.opensearch.rest;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpRequest;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -65,9 +64,14 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.unit.ByteSizeValue.parseBytesSizeValue;
 import static org.opensearch.common.unit.TimeValue.parseTimeValue;
+import static org.opensearch.core.common.unit.ByteSizeValue.parseBytesSizeValue;
 
+/**
+ * REST Request
+ *
+ * @opensearch.api
+ */
 public class RestRequest implements ToXContent.Params {
 
     // tchar pattern as defined by RFC7230 section 3.2.6
@@ -80,7 +84,7 @@ public class RestRequest implements ToXContent.Params {
     private final Map<String, List<String>> headers;
     private final String rawPath;
     private final Set<String> consumedParams = new HashSet<>();
-    private final SetOnce<XContentType> xContentType = new SetOnce<>();
+    private final SetOnce<MediaType> mediaType = new SetOnce<>();
     private final HttpChannel httpChannel;
 
     private HttpRequest httpRequest;
@@ -113,14 +117,14 @@ private RestRequest(
         HttpChannel httpChannel,
         long requestId
     ) {
-        final XContentType xContentType;
+        final MediaType mediaType;
         try {
-            xContentType = parseContentType(headers.get("Content-Type"));
+            mediaType = parseContentType(headers.get("Content-Type"));
         } catch (final IllegalArgumentException e) {
             throw new ContentTypeHeaderException(e);
         }
-        if (xContentType != null) {
-            this.xContentType.set(xContentType);
+        if (mediaType != null) {
+            this.mediaType.set(mediaType);
         }
         this.xContentRegistry = xContentRegistry;
         this.httpRequest = httpRequest;
@@ -224,6 +228,11 @@ public static RestRequest requestWithoutParameters(
         );
     }
 
+    /**
+     * The method used.
+     *
+     * @opensearch.internal
+     */
     public enum Method {
         GET,
         POST,
@@ -286,7 +295,7 @@ protected BytesReference content(final boolean contentConsumed) {
     public final BytesReference requiredContent() {
         if (hasContent() == false) {
             throw new OpenSearchParseException("request body is required");
-        } else if (xContentType.get() == null) {
+        } else if (mediaType.get() == null) {
             throw new IllegalStateException("unknown content type");
         }
         return content();
@@ -327,12 +336,12 @@ public final long getRequestId() {
     }
 
     /**
-     * The {@link XContentType} that was parsed from the {@code Content-Type} header. This value will be {@code null} in the case of
+     * The {@link MediaType} that was parsed from the {@code Content-Type} header. This value will be {@code null} in the case of
      * a request without a valid {@code Content-Type} header, a request without content ({@link #hasContent()}, or a plain text request
      */
     @Nullable
-    public final XContentType getXContentType() {
-        return xContentType.get();
+    public final MediaType getMediaType() {
+        return mediaType.get();
     }
 
     public HttpChannel getHttpChannel() {
@@ -373,7 +382,7 @@ public Map<String, String> params() {
      *
      * @return the list of currently consumed parameters.
      */
-    List<String> consumedParams() {
+    public List<String> consumedParams() {
         return new ArrayList<>(consumedParams);
     }
 
@@ -477,7 +486,7 @@ public NamedXContentRegistry getXContentRegistry() {
      */
     public final XContentParser contentParser() throws IOException {
         BytesReference content = requiredContent(); // will throw exception if body or content type missing
-        return xContentType.get().xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, content.streamInput());
+        return mediaType.get().xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, content.streamInput());
     }
 
     /**
@@ -505,7 +514,7 @@ public final boolean hasContentOrSourceParam() {
      * if you need to handle the absence request content gracefully.
      */
     public final XContentParser contentOrSourceParamParser() throws IOException {
-        Tuple<XContentType, BytesReference> tuple = contentOrSourceParam();
+        Tuple<MediaType, BytesReference> tuple = contentOrSourceParam();
         return tuple.v1().xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, tuple.v2().streamInput());
     }
 
@@ -516,12 +525,12 @@ public final XContentParser contentOrSourceParamParser() throws IOException {
      */
     public final void withContentOrSourceParamParserOrNull(CheckedConsumer<XContentParser, IOException> withParser) throws IOException {
         if (hasContentOrSourceParam()) {
-            Tuple<XContentType, BytesReference> tuple = contentOrSourceParam();
+            Tuple<MediaType, BytesReference> tuple = contentOrSourceParam();
             BytesReference content = tuple.v2();
-            XContentType xContentType = tuple.v1();
+            MediaType mediaType = tuple.v1();
             try (
                 InputStream stream = content.streamInput();
-                XContentParser parser = xContentType.xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, stream)
+                XContentParser parser = mediaType.xContent().createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, stream)
             ) {
                 withParser.accept(parser);
             }
@@ -534,11 +543,11 @@ public final void withContentOrSourceParamParserOrNull(CheckedConsumer<XContentP
      * Get the content of the request or the contents of the {@code source} param or throw an exception if both are missing.
      * Prefer {@link #contentOrSourceParamParser()} or {@link #withContentOrSourceParamParserOrNull(CheckedConsumer)} if you need a parser.
      */
-    public final Tuple<XContentType, BytesReference> contentOrSourceParam() {
+    public final Tuple<MediaType, BytesReference> contentOrSourceParam() {
         if (hasContentOrSourceParam() == false) {
             throw new OpenSearchParseException("request body or source parameter is required");
         } else if (hasContent()) {
-            return new Tuple<>(xContentType.get(), requiredContent());
+            return new Tuple<>(mediaType.get(), requiredContent());
         }
         String source = param("source");
         String typeParam = param("source_content_type");
@@ -546,18 +555,18 @@ public final Tuple<XContentType, BytesReference> contentOrSourceParam() {
             throw new IllegalStateException("source and source_content_type parameters are required");
         }
         BytesArray bytes = new BytesArray(source);
-        final XContentType xContentType = parseContentType(Collections.singletonList(typeParam));
-        if (xContentType == null) {
+        final MediaType mediaType = parseContentType(Collections.singletonList(typeParam));
+        if (mediaType == null) {
             throw new IllegalStateException("Unknown value for source_content_type [" + typeParam + "]");
         }
-        return new Tuple<>(xContentType, bytes);
+        return new Tuple<>(mediaType, bytes);
     }
 
     /**
      * Parses the given content type string for the media type. This method currently ignores parameters.
      */
     // TODO stop ignoring parameters such as charset...
-    public static XContentType parseContentType(List<String> header) {
+    public static MediaType parseContentType(List<String> header) {
         if (header == null || header.isEmpty()) {
             return null;
         } else if (header.size() > 1) {
@@ -571,7 +580,7 @@ public static XContentType parseContentType(List<String> header) {
             if (splitMediaType.length == 2
                 && TCHAR_PATTERN.matcher(splitMediaType[0]).matches()
                 && TCHAR_PATTERN.matcher(splitMediaType[1].trim()).matches()) {
-                return XContentType.fromMediaType(elements[0]);
+                return MediaType.fromMediaType(elements[0]);
             } else {
                 throw new IllegalArgumentException("invalid Content-Type header [" + rawContentType + "]");
             }
@@ -580,31 +589,10 @@ public static XContentType parseContentType(List<String> header) {
     }
 
     /**
-     * The method is only used to validate whether the values of the 2 request parameters "master_timeout" and "cluster_manager_timeout" is the same value or not.
-     * If the 2 values are not the same, throw an {@link OpenSearchParseException}.
-     * @param keys Names of the request parameters.
-     * @deprecated The method will be removed along with the request parameter "master_timeout".
+     * Thrown if there is an error in the content type header.
+     *
+     * @opensearch.internal
      */
-    @Deprecated
-    public void validateParamValuesAreEqual(String... keys) {
-        // Track the last seen value and ensure that every subsequent value matches it.
-        // The value to be tracked is the non-empty values of the parameters with the key.
-        String lastSeenValue = null;
-        for (String key : keys) {
-            String value = param(key);
-            if (!Strings.isNullOrEmpty(value)) {
-                if (lastSeenValue == null || value.equals(lastSeenValue)) {
-                    lastSeenValue = value;
-                } else {
-                    throw new OpenSearchParseException(
-                        "The values of the request parameters: {} are required to be equal, otherwise please only assign value to one of the request parameters.",
-                        Arrays.toString(keys)
-                    );
-                }
-            }
-        }
-    }
-
     public static class ContentTypeHeaderException extends RuntimeException {
 
         ContentTypeHeaderException(final IllegalArgumentException cause) {
@@ -613,6 +601,11 @@ public static class ContentTypeHeaderException extends RuntimeException {
 
     }
 
+    /**
+     * Thrown if there is a bad parameter.
+     *
+     * @opensearch.internal
+     */
     public static class BadParameterException extends RuntimeException {
 
         BadParameterException(final IllegalArgumentException cause) {
diff --git a/server/src/main/java/org/opensearch/rest/RestRequestFilter.java b/server/src/main/java/org/opensearch/rest/RestRequestFilter.java
index 9b17dd4432552..7987138df9bc5 100644
--- a/server/src/main/java/org/opensearch/rest/RestRequestFilter.java
+++ b/server/src/main/java/org/opensearch/rest/RestRequestFilter.java
@@ -33,13 +33,13 @@
 package org.opensearch.rest;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
@@ -48,6 +48,8 @@
 /**
  * Identifies an object that supplies a filter for the content of a {@link RestRequest}. This interface should be implemented by a
  * {@link org.opensearch.rest.RestHandler} that expects there will be sensitive content in the body of the request such as a password
+ *
+ * @opensearch.api
  */
 public interface RestRequestFilter {
 
diff --git a/server/src/main/java/org/opensearch/rest/RestResponse.java b/server/src/main/java/org/opensearch/rest/RestResponse.java
index 80d80cec3b30b..2eff746e8508c 100644
--- a/server/src/main/java/org/opensearch/rest/RestResponse.java
+++ b/server/src/main/java/org/opensearch/rest/RestResponse.java
@@ -33,7 +33,9 @@
 package org.opensearch.rest;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -42,6 +44,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * OpenSearch REST response
+ *
+ * @opensearch.api
+ */
 public abstract class RestResponse {
 
     private Map<String, List<String>> customHeaders;
@@ -52,7 +59,7 @@ public abstract class RestResponse {
     public abstract String contentType();
 
     /**
-     * The response content. Note, if the content is {@link org.opensearch.common.lease.Releasable} it
+     * The response content. Note, if the content is {@link Releasable} it
      * should automatically be released when done by the channel sending it.
      */
     public abstract BytesReference content();
diff --git a/server/src/main/java/org/opensearch/rest/RestUtils.java b/server/src/main/java/org/opensearch/rest/RestUtils.java
index 913910cead210..c165fccf70789 100644
--- a/server/src/main/java/org/opensearch/rest/RestUtils.java
+++ b/server/src/main/java/org/opensearch/rest/RestUtils.java
@@ -33,8 +33,8 @@
 package org.opensearch.rest;
 
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
 import org.opensearch.common.path.PathTrie;
+import org.opensearch.core.common.Strings;
 
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.regex.Pattern;
 
+/**
+ * REST utility class
+ *
+ * @opensearch.api
+ */
 public class RestUtils {
 
     /**
diff --git a/server/src/main/java/org/opensearch/rest/action/RestActionListener.java b/server/src/main/java/org/opensearch/rest/action/RestActionListener.java
index d0e897ea811e0..846265b19e726 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestActionListener.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestActionListener.java
@@ -34,7 +34,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 
@@ -43,6 +43,8 @@
 /**
  * An action listener that requires {@link #processResponse(Object)} to be implemented
  * and will automatically handle failures.
+ *
+ * @opensearch.api
  */
 public abstract class RestActionListener<Response> implements ActionListener<Response> {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/RestActions.java b/server/src/main/java/org/opensearch/rest/action/RestActions.java
index 7c5aaf4e763c3..b074a4bf4e01d 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestActions.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestActions.java
@@ -34,18 +34,19 @@
 
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.FailedNodeException;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.action.support.nodes.BaseNodeResponse;
 import org.opensearch.action.support.nodes.BaseNodesResponse;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContent.Params;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContent.Params;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.Operator;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -54,13 +55,17 @@
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.List;
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * REST actions
+ *
+ * @opensearch.api
+ */
 public class RestActions {
 
     public static final ParseField _SHARDS_FIELD = new ParseField("_shards");
diff --git a/server/src/main/java/org/opensearch/rest/action/RestBuilderListener.java b/server/src/main/java/org/opensearch/rest/action/RestBuilderListener.java
index 03e70388660de..89a2b80946b23 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestBuilderListener.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestBuilderListener.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.rest.action;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestResponse;
 
 /**
  * A REST action listener that builds an {@link XContentBuilder} based response.
+ *
+ * @opensearch.api
  */
 public abstract class RestBuilderListener<Response> extends RestResponseListener<Response> {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/RestCancellableNodeClient.java b/server/src/main/java/org/opensearch/rest/action/RestCancellableNodeClient.java
index 046fb060733bf..339482af1dd74 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestCancellableNodeClient.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestCancellableNodeClient.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.rest.action;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.client.Client;
 import org.opensearch.client.FilterClient;
 import org.opensearch.client.OriginSettingClient;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -58,6 +58,8 @@
 /**
  * A {@linkplain Client} that cancels tasks executed locally when the provided {@link HttpChannel}
  * is closed before completion.
+ *
+ * @opensearch.api
  */
 public class RestCancellableNodeClient extends FilterClient {
     private static final Map<HttpChannel, CloseListener> httpChannels = new ConcurrentHashMap<>();
diff --git a/server/src/main/java/org/opensearch/rest/action/RestFieldCapabilitiesAction.java b/server/src/main/java/org/opensearch/rest/action/RestFieldCapabilitiesAction.java
index dea8e80687ed3..7020c7cab10df 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestFieldCapabilitiesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestFieldCapabilitiesAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.fieldcaps.FieldCapabilitiesRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 
@@ -47,6 +47,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to get field capabilities
+ *
+ * @opensearch.api
+ */
 public class RestFieldCapabilitiesAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/RestMainAction.java b/server/src/main/java/org/opensearch/rest/action/RestMainAction.java
index a3a37ba7699d8..1554ed7c1ef64 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestMainAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestMainAction.java
@@ -36,12 +36,12 @@
 import org.opensearch.action.main.MainRequest;
 import org.opensearch.action.main.MainResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,6 +51,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
 
+/**
+ * Main OpenSearch Transport action
+ *
+ * @opensearch.api
+ */
 public class RestMainAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/RestResponseListener.java b/server/src/main/java/org/opensearch/rest/action/RestResponseListener.java
index 63d5400041265..4dd1aa912dd40 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestResponseListener.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestResponseListener.java
@@ -38,6 +38,8 @@
 /**
  * A REST enabled action listener that has a basic onFailure implementation, and requires
  * sub classes to only implement {@link #buildResponse(Object)}.
+ *
+ * @opensearch.api
  */
 public abstract class RestResponseListener<Response> extends RestActionListener<Response> {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/RestStatusToXContentListener.java b/server/src/main/java/org/opensearch/rest/action/RestStatusToXContentListener.java
index ade2ed6c3bd65..ae6795dd89b7b 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestStatusToXContentListener.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestStatusToXContentListener.java
@@ -32,16 +32,18 @@
 package org.opensearch.rest.action;
 
 import org.opensearch.common.xcontent.StatusToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.util.function.Function;
 
 /**
  * Content listener that extracts that {@link RestStatus} from the response.
+ *
+ * @opensearch.api
  */
 public class RestStatusToXContentListener<Response extends StatusToXContentObject> extends RestToXContentListener<Response> {
     private final Function<Response, String> extractLocation;
diff --git a/server/src/main/java/org/opensearch/rest/action/RestToXContentListener.java b/server/src/main/java/org/opensearch/rest/action/RestToXContentListener.java
index 8ea55a4ccf493..883f197807187 100644
--- a/server/src/main/java/org/opensearch/rest/action/RestToXContentListener.java
+++ b/server/src/main/java/org/opensearch/rest/action/RestToXContentListener.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.rest.action;
 
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 /**
  * A REST based action listener that assumes the response is of type {@link ToXContent} and automatically
  * builds an XContent based response (wrapping the toXContent in startObject/endObject).
+ *
+ * @opensearch.api
  */
 public class RestToXContentListener<Response extends ToXContentObject> extends RestResponseListener<Response> {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionAction.java
index c5f9d168a725c..9addbcca27258 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionAction.java
@@ -37,8 +37,8 @@
 import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsAction;
 import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,6 +49,11 @@
 
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to add voting config exclusions
+ *
+ * @opensearch.api
+ */
 public class RestAddVotingConfigExclusionAction extends BaseRestHandler {
     private static final TimeValue DEFAULT_TIMEOUT = TimeValue.timeValueSeconds(30L);
     private static final Logger logger = LogManager.getLogger(RestAddVotingConfigExclusionAction.class);
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCancelTasksAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCancelTasksAction.java
index 5415ad260b9e8..061ee022c1984 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCancelTasksAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCancelTasksAction.java
@@ -35,10 +35,10 @@
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.List;
@@ -49,6 +49,11 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.action.admin.cluster.RestListTasksAction.listTasksResponseListener;
 
+/**
+ * Transport action to cancel tasks
+ *
+ * @opensearch.api
+ */
 public class RestCancelTasksAction extends BaseRestHandler {
     private final Supplier<DiscoveryNodes> nodesInCluster;
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCleanupRepositoryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCleanupRepositoryAction.java
index 2371581cefccb..a1d343a628173 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCleanupRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCleanupRepositoryAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.repositories.cleanup.CleanupRepositoryRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,9 +48,13 @@
 
 /**
  * Cleans up a repository
+ *
+ * @opensearch.api
  */
 public class RestCleanupRepositoryAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestCleanupRepositoryAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(POST, "/_snapshot/{repository}/_cleanup"));
@@ -64,7 +69,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         CleanupRepositoryRequest cleanupRepositoryRequest = cleanupRepositoryRequest(request.param("repository"));
         cleanupRepositoryRequest.timeout(request.paramAsTime("timeout", cleanupRepositoryRequest.timeout()));
-        cleanupRepositoryRequest.masterNodeTimeout(request.paramAsTime("master_timeout", cleanupRepositoryRequest.masterNodeTimeout()));
+        cleanupRepositoryRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", cleanupRepositoryRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(cleanupRepositoryRequest, request);
         return channel -> client.admin().cluster().cleanupRepository(cleanupRepositoryRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClearVotingConfigExclusionsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClearVotingConfigExclusionsAction.java
index 73a5a0c321b28..aa8a4879da5ca 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClearVotingConfigExclusionsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClearVotingConfigExclusionsAction.java
@@ -45,6 +45,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to clear voting config exclusions
+ *
+ * @opensearch.api
+ */
 public class RestClearVotingConfigExclusionsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCloneSnapshotAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCloneSnapshotAction.java
index 5c10c96c17227..865b5f070965e 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCloneSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCloneSnapshotAction.java
@@ -35,6 +35,7 @@
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.support.XContentMapValues;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -49,9 +50,13 @@
 
 /**
  * Clones indices from one snapshot into another snapshot in the same repository
+ *
+ * @opensearch.api
  */
 public class RestCloneSnapshotAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestCloneSnapshotAction.class);
+
     @Override
     public List<Route> routes() {
         return Collections.singletonList(new Route(PUT, "/_snapshot/{repository}/{snapshot}/_clone/{target_snapshot}"));
@@ -71,7 +76,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             request.param("target_snapshot"),
             XContentMapValues.nodeStringArrayValue(source.getOrDefault("indices", Collections.emptyList()))
         );
-        cloneSnapshotRequest.masterNodeTimeout(request.paramAsTime("master_timeout", cloneSnapshotRequest.masterNodeTimeout()));
+        cloneSnapshotRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", cloneSnapshotRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(cloneSnapshotRequest, request);
         cloneSnapshotRequest.indicesOptions(IndicesOptions.fromMap(source, cloneSnapshotRequest.indicesOptions()));
         return channel -> client.admin().cluster().cloneSnapshot(cloneSnapshotRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterAllocationExplainAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterAllocationExplainAction.java
index b059e75870e87..f373d141a3c28 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterAllocationExplainAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterAllocationExplainAction.java
@@ -35,14 +35,14 @@
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainRequest;
 import org.opensearch.action.admin.cluster.allocation.ClusterAllocationExplainResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.io.IOException;
@@ -55,6 +55,8 @@
 
 /**
  * Class handling cluster allocation explanation at the REST level
+ *
+ * @opensearch.api
  */
 public class RestClusterAllocationExplainAction extends BaseRestHandler {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingAction.java
new file mode 100644
index 0000000000000..d9dedf8d14506
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingAction.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.DELETE;
+
+/**
+ * Delete Weighted Round Robin based shard routing weights
+ *
+ * @opensearch.api
+ *
+ */
+public class RestClusterDeleteWeightedRoutingAction extends BaseRestHandler {
+
+    private static final Logger logger = LogManager.getLogger(RestClusterDeleteWeightedRoutingAction.class);
+
+    @Override
+    public List<Route> routes() {
+        return unmodifiableList(
+            asList(
+                new Route(DELETE, "/_cluster/routing/awareness/weights"),
+                new Route(DELETE, "/_cluster/routing/awareness/{attribute}/weights")
+            )
+        );
+    }
+
+    @Override
+    public String getName() {
+        return "delete_weighted_routing_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        ClusterDeleteWeightedRoutingRequest clusterDeleteWeightedRoutingRequest = createRequest(request);
+        return channel -> client.admin()
+            .cluster()
+            .deleteWeightedRouting(clusterDeleteWeightedRoutingRequest, new RestToXContentListener<>(channel));
+    }
+
+    public static ClusterDeleteWeightedRoutingRequest createRequest(RestRequest request) throws IOException {
+        ClusterDeleteWeightedRoutingRequest deleteWeightedRoutingRequest = Requests.deleteWeightedRoutingRequest(
+            request.param("attribute")
+        );
+        request.applyContentParser(p -> deleteWeightedRoutingRequest.source(p.mapStrings()));
+        return deleteWeightedRoutingRequest;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetSettingsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetSettingsAction.java
index 003f1bec11d87..b01db973b74ae 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetSettingsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetSettingsAction.java
@@ -38,16 +38,17 @@
 import org.opensearch.client.Requests;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.io.IOException;
@@ -57,8 +58,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get settings
+ *
+ * @opensearch.api
+ */
 public class RestClusterGetSettingsAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterGetSettingsAction.class);
+
     private final Settings settings;
     private final ClusterSettings clusterSettings;
     private final SettingsFilter settingsFilter;
@@ -84,7 +92,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         ClusterStateRequest clusterStateRequest = Requests.clusterStateRequest().routingTable(false).nodes(false);
         final boolean renderDefaults = request.paramAsBoolean("include_defaults", false);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestBuilderListener<ClusterStateResponse>(channel) {
             @Override
             public RestResponse buildResponse(ClusterStateResponse response, XContentBuilder builder) throws Exception {
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetWeightedRoutingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetWeightedRoutingAction.java
new file mode 100644
index 0000000000000..7c9d1190f0b1d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterGetWeightedRoutingAction.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * Fetch Weighted Round Robin based shard routing weights
+ *
+ * @opensearch.api
+ *
+ */
+public class RestClusterGetWeightedRoutingAction extends BaseRestHandler {
+
+    private static final Logger logger = LogManager.getLogger(RestClusterGetWeightedRoutingAction.class);
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(GET, "/_cluster/routing/awareness/{attribute}/weights"));
+    }
+
+    @Override
+    public String getName() {
+        return "get_weighted_routing_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        ClusterGetWeightedRoutingRequest getWeightedRoutingRequest = Requests.getWeightedRoutingRequest(request.param("attribute"));
+        getWeightedRoutingRequest.local(request.paramAsBoolean("local", getWeightedRoutingRequest.local()));
+        return channel -> client.admin().cluster().getWeightedRouting(getWeightedRoutingRequest, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthAction.java
index 8b782e4399e73..6a6f6937ff18a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthAction.java
@@ -38,7 +38,8 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestStatusToXContentListener;
@@ -54,8 +55,15 @@
 import static org.opensearch.client.Requests.clusterHealthRequest;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get cluster health
+ *
+ * @opensearch.api
+ */
 public class RestClusterHealthAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterHealthAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cluster/health"), new Route(GET, "/_cluster/health/{index}")));
@@ -81,8 +89,22 @@ public static ClusterHealthRequest fromRequest(final RestRequest request) {
         final ClusterHealthRequest clusterHealthRequest = clusterHealthRequest(Strings.splitStringByCommaToArray(request.param("index")));
         clusterHealthRequest.indicesOptions(IndicesOptions.fromRequest(request, clusterHealthRequest.indicesOptions()));
         clusterHealthRequest.local(request.paramAsBoolean("local", clusterHealthRequest.local()));
-        clusterHealthRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterHealthRequest.masterNodeTimeout()));
+        clusterHealthRequest.ensureNodeWeighedIn(
+            request.paramAsBoolean("ensure_node_weighed_in", clusterHealthRequest.ensureNodeWeighedIn())
+        );
+        clusterHealthRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterHealthRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterHealthRequest, request);
         clusterHealthRequest.timeout(request.paramAsTime("timeout", clusterHealthRequest.timeout()));
+        String awarenessAttribute = request.param("awareness_attribute");
+        if (awarenessAttribute != null) {
+            clusterHealthRequest.setAwarenessAttribute(awarenessAttribute);
+        }
+        String level = request.param("level");
+        if (level != null) {
+            clusterHealthRequest.setLevel(level);
+        }
         String waitForStatus = request.param("wait_for_status");
         if (waitForStatus != null) {
             clusterHealthRequest.waitForStatus(ClusterHealthStatus.valueOf(waitForStatus.toUpperCase(Locale.ROOT)));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterPutWeightedRoutingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterPutWeightedRoutingAction.java
new file mode 100644
index 0000000000000..5f845b7a66c1f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterPutWeightedRoutingAction.java
@@ -0,0 +1,58 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.PUT;
+
+/**
+ * Update Weighted Round Robin based shard routing weights
+ *
+ * @opensearch.api
+ *
+ */
+public class RestClusterPutWeightedRoutingAction extends BaseRestHandler {
+
+    private static final Logger logger = LogManager.getLogger(RestClusterPutWeightedRoutingAction.class);
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(PUT, "/_cluster/routing/awareness/{attribute}/weights"));
+    }
+
+    @Override
+    public String getName() {
+        return "put_weighted_routing_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        ClusterPutWeightedRoutingRequest putWeightedRoutingRequest = createRequest(request);
+        return channel -> client.admin().cluster().putWeightedRouting(putWeightedRoutingRequest, new RestToXContentListener<>(channel));
+    }
+
+    public static ClusterPutWeightedRoutingRequest createRequest(RestRequest request) throws IOException {
+        ClusterPutWeightedRoutingRequest putWeightedRoutingRequest = Requests.putWeightedRoutingRequest(request.param("attribute"));
+        request.applyContentParser(p -> putWeightedRoutingRequest.source(p.mapOrdered()));
+        return putWeightedRoutingRequest;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterRerouteAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterRerouteAction.java
index f519da109ba09..91ec49e99bdf3 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterRerouteAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterRerouteAction.java
@@ -37,13 +37,13 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -58,6 +58,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to reroute documents
+ *
+ * @opensearch.api
+ */
 public class RestClusterRerouteAction extends BaseRestHandler {
     private static final ObjectParser<ClusterRerouteRequest, Void> PARSER = new ObjectParser<>("cluster_reroute");
     static {
@@ -80,10 +85,10 @@ public RestClusterRerouteAction(SettingsFilter settingsFilter) {
     }
 
     // TODO: Remove the DeprecationLogger after removing MASTER_ROLE.
-    // It's used to log deprecation when request parameter 'metric' contains 'master_node'.
+    // It's used to log deprecation when request parameter 'metric' contains 'master_node', or request parameter 'master_timeout' is used.
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterRerouteAction.class);
     private static final String DEPRECATED_MESSAGE_MASTER_NODE =
-        "Deprecated value [master_node] used for parameter [metric]. To promote inclusive language, please use [cluster_manager_node] instead. It will be unsupported in a future major version.";
+        "Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.";
 
     @Override
     public List<Route> routes() {
@@ -143,7 +148,10 @@ public static ClusterRerouteRequest createRequest(RestRequest request) throws IO
         clusterRerouteRequest.explain(request.paramAsBoolean("explain", clusterRerouteRequest.explain()));
         clusterRerouteRequest.timeout(request.paramAsTime("timeout", clusterRerouteRequest.timeout()));
         clusterRerouteRequest.setRetryFailed(request.paramAsBoolean("retry_failed", clusterRerouteRequest.isRetryFailed()));
-        clusterRerouteRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterRerouteRequest.masterNodeTimeout()));
+        clusterRerouteRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterRerouteRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterRerouteRequest, request);
         request.applyContentParser(parser -> PARSER.parse(parser, clusterRerouteRequest, null));
         return clusterRerouteRequest;
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterSearchShardsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterSearchShardsAction.java
index 20cd11e0308fe..3555576433104 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterSearchShardsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterSearchShardsAction.java
@@ -36,7 +36,7 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.Requests;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,6 +49,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to search shards
+ *
+ * @opensearch.api
+ */
 public class RestClusterSearchShardsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStateAction.java
index 32aa055c18300..8950ae04388d5 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStateAction.java
@@ -39,17 +39,17 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.io.IOException;
@@ -64,6 +64,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get cluster state
+ *
+ * @opensearch.api
+ */
 public class RestClusterStateAction extends BaseRestHandler {
 
     private final SettingsFilter settingsFilter;
@@ -73,10 +78,10 @@ public RestClusterStateAction(SettingsFilter settingsFilter) {
     }
 
     // TODO: Remove the DeprecationLogger after removing MASTER_ROLE.
-    // It's used to log deprecation when request parameter 'metric' contains 'master_node'.
+    // It's used to log deprecation when request parameter 'metric' contains 'master_node', or request parameter 'master_timeout' is used.
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterStateAction.class);
     private static final String DEPRECATED_MESSAGE_MASTER_NODE =
-        "Deprecated value [master_node] used for parameter [metric]. To promote inclusive language, please use [cluster_manager_node] instead. It will be unsupported in a future major version.";
+        "Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.";
 
     @Override
     public String getName() {
@@ -104,7 +109,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         final ClusterStateRequest clusterStateRequest = Requests.clusterStateRequest();
         clusterStateRequest.indicesOptions(IndicesOptions.fromRequest(request, clusterStateRequest.indicesOptions()));
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
         if (request.hasParam("wait_for_metadata_version")) {
             clusterStateRequest.waitForMetadataVersion(request.paramAsLong("wait_for_metadata_version", 0));
         }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStatsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStatsAction.java
index 9bbabcdba146b..0766e838210fa 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStatsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStatsAction.java
@@ -45,6 +45,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get cluster stats
+ *
+ * @opensearch.api
+ */
 public class RestClusterStatsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterUpdateSettingsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterUpdateSettingsAction.java
index bbe1bba70926f..fa3066acda93b 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterUpdateSettingsAction.java
@@ -35,8 +35,9 @@
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.client.Requests;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,8 +50,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to update cluster settings
+ *
+ * @opensearch.api
+ */
 public class RestClusterUpdateSettingsAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterUpdateSettingsAction.class);
+
     private static final String PERSISTENT = "persistent";
     private static final String TRANSIENT = "transient";
 
@@ -68,9 +76,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         final ClusterUpdateSettingsRequest clusterUpdateSettingsRequest = Requests.clusterUpdateSettingsRequest();
         clusterUpdateSettingsRequest.timeout(request.paramAsTime("timeout", clusterUpdateSettingsRequest.timeout()));
-        clusterUpdateSettingsRequest.masterNodeTimeout(
-            request.paramAsTime("master_timeout", clusterUpdateSettingsRequest.masterNodeTimeout())
+        clusterUpdateSettingsRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterUpdateSettingsRequest.clusterManagerNodeTimeout())
         );
+        parseDeprecatedMasterTimeoutParameter(clusterUpdateSettingsRequest, request);
         Map<String, Object> source;
         try (XContentParser parser = request.contentParser()) {
             source = parser.map();
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCreateSnapshotAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCreateSnapshotAction.java
index c53f1d0cd5637..5eb5d5bd7fbd5 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCreateSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestCreateSnapshotAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,9 +50,13 @@
 
 /**
  * Creates a new snapshot
+ *
+ * @opensearch.api
  */
 public class RestCreateSnapshotAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestCreateSnapshotAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -68,7 +73,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         CreateSnapshotRequest createSnapshotRequest = createSnapshotRequest(request.param("repository"), request.param("snapshot"));
         request.applyContentParser(p -> createSnapshotRequest.source(p.mapOrdered()));
-        createSnapshotRequest.masterNodeTimeout(request.paramAsTime("master_timeout", createSnapshotRequest.masterNodeTimeout()));
+        createSnapshotRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", createSnapshotRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(createSnapshotRequest, request);
         createSnapshotRequest.waitForCompletion(request.paramAsBoolean("wait_for_completion", false));
         return channel -> client.admin().cluster().createSnapshot(createSnapshotRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDecommissionAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDecommissionAction.java
new file mode 100644
index 0000000000000..c041974165eb6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDecommissionAction.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.PUT;
+
+/**
+ * Registers decommission action
+ *
+ * @opensearch.api
+ */
+public class RestDecommissionAction extends BaseRestHandler {
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(PUT, "/_cluster/decommission/awareness/{awareness_attribute_name}/{awareness_attribute_value}"));
+    }
+
+    @Override
+    public String getName() {
+        return "decommission_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        DecommissionRequest decommissionRequest = createRequest(request);
+        return channel -> client.admin().cluster().decommission(decommissionRequest, new RestToXContentListener<>(channel));
+    }
+
+    DecommissionRequest createRequest(RestRequest request) throws IOException {
+        DecommissionRequest decommissionRequest = Requests.decommissionRequest();
+        String attributeName = request.param("awareness_attribute_name");
+        String attributeValue = request.param("awareness_attribute_value");
+        // Check if we have no delay set.
+        boolean noDelay = request.paramAsBoolean("no_delay", false);
+        decommissionRequest.setNoDelay(noDelay);
+
+        if (request.hasParam("delay_timeout")) {
+            TimeValue delayTimeout = request.paramAsTime("delay_timeout", DecommissionRequest.DEFAULT_NODE_DRAINING_TIMEOUT);
+            decommissionRequest.setDelayTimeout(delayTimeout);
+        }
+        return decommissionRequest.setDecommissionAttribute(new DecommissionAttribute(attributeName, attributeValue));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateAction.java
new file mode 100644
index 0000000000000..9fd7ae2248c30
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateAction.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.DELETE;
+
+/**
+ * Clears the decommission metadata.
+ *
+ * @opensearch.api
+ */
+public class RestDeleteDecommissionStateAction extends BaseRestHandler {
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(DELETE, "/_cluster/decommission/awareness"));
+    }
+
+    @Override
+    public String getName() {
+        return "delete_decommission_state_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        DeleteDecommissionStateRequest deleteDecommissionStateRequest = createRequest();
+        return channel -> client.admin()
+            .cluster()
+            .deleteDecommissionState(deleteDecommissionStateRequest, new RestToXContentListener<>(channel));
+    }
+
+    DeleteDecommissionStateRequest createRequest() {
+        return Requests.deleteDecommissionStateRequest();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteRepositoryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteRepositoryAction.java
index 4f8771b5db171..d8e13c8b470e2 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteRepositoryAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,9 +48,13 @@
 
 /**
  * Unregisters a repository
+ *
+ * @opensearch.api
  */
 public class RestDeleteRepositoryAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteRepositoryAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_snapshot/{repository}"));
@@ -64,7 +69,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         DeleteRepositoryRequest deleteRepositoryRequest = deleteRepositoryRequest(request.param("repository"));
         deleteRepositoryRequest.timeout(request.paramAsTime("timeout", deleteRepositoryRequest.timeout()));
-        deleteRepositoryRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteRepositoryRequest.masterNodeTimeout()));
+        deleteRepositoryRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", deleteRepositoryRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(deleteRepositoryRequest, request);
         return channel -> client.admin().cluster().deleteRepository(deleteRepositoryRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteSnapshotAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteSnapshotAction.java
index 57b651215bc4f..31528dbe6ccf0 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteSnapshotAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,9 +49,13 @@
 
 /**
  * Deletes a snapshot
+ *
+ * @opensearch.api
  */
 public class RestDeleteSnapshotAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteSnapshotAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_snapshot/{repository}/{snapshot}"));
@@ -67,7 +72,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             request.param("repository"),
             Strings.splitStringByCommaToArray(request.param("snapshot"))
         );
-        deleteSnapshotRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteSnapshotRequest.masterNodeTimeout()));
+        deleteSnapshotRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", deleteSnapshotRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(deleteSnapshotRequest, request);
         return channel -> client.admin().cluster().deleteSnapshot(deleteSnapshotRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteStoredScriptAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteStoredScriptAction.java
index 8703899d5ed14..51e11eaded7bd 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestDeleteStoredScriptAction.java
@@ -33,6 +33,7 @@
 
 import org.opensearch.action.admin.cluster.storedscripts.DeleteStoredScriptRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -43,8 +44,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete stored script
+ *
+ * @opensearch.api
+ */
 public class RestDeleteStoredScriptAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteStoredScriptAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_scripts/{id}"));
@@ -60,7 +68,10 @@ public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client
         String id = request.param("id");
         DeleteStoredScriptRequest deleteStoredScriptRequest = new DeleteStoredScriptRequest(id);
         deleteStoredScriptRequest.timeout(request.paramAsTime("timeout", deleteStoredScriptRequest.timeout()));
-        deleteStoredScriptRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteStoredScriptRequest.masterNodeTimeout()));
+        deleteStoredScriptRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", deleteStoredScriptRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(deleteStoredScriptRequest, request);
 
         return channel -> client.admin().cluster().deleteStoredScript(deleteStoredScriptRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetDecommissionStateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetDecommissionStateAction.java
new file mode 100644
index 0000000000000..5d72adbd6ae08
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetDecommissionStateAction.java
@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.get.GetDecommissionStateRequest;
+import org.opensearch.client.Requests;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * Returns decommissioned attribute information
+ *
+ * @opensearch.api
+ */
+public class RestGetDecommissionStateAction extends BaseRestHandler {
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(GET, "/_cluster/decommission/awareness/{awareness_attribute_name}/_status"));
+    }
+
+    @Override
+    public String getName() {
+        return "get_decommission_state_action";
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
+        GetDecommissionStateRequest getDecommissionStateRequest = Requests.getDecommissionStateRequest();
+        String attributeName = request.param("awareness_attribute_name");
+        getDecommissionStateRequest.attributeName(attributeName);
+        return channel -> client.admin().cluster().getDecommissionState(getDecommissionStateRequest, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetRepositoriesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetRepositoriesAction.java
index 2a359fa08eb59..a9c2d18645af2 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetRepositoriesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetRepositoriesAction.java
@@ -34,9 +34,10 @@
 
 import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -52,9 +53,13 @@
 
 /**
  * Returns repository information
+ *
+ * @opensearch.api
  */
 public class RestGetRepositoriesAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetRepositoriesAction.class);
+
     private final SettingsFilter settingsFilter;
 
     public RestGetRepositoriesAction(SettingsFilter settingsFilter) {
@@ -75,7 +80,10 @@ public List<Route> routes() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         final String[] repositories = request.paramAsStringArray("repository", Strings.EMPTY_ARRAY);
         GetRepositoriesRequest getRepositoriesRequest = getRepositoryRequest(repositories);
-        getRepositoriesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getRepositoriesRequest.masterNodeTimeout()));
+        getRepositoriesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getRepositoriesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getRepositoriesRequest, request);
         getRepositoriesRequest.local(request.paramAsBoolean("local", getRepositoriesRequest.local()));
         settingsFilter.addFilterSettingParams(request);
         return channel -> client.admin().cluster().getRepositories(getRepositoriesRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptContextAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptContextAction.java
index bc619b31a1d6a..5111397316b4c 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptContextAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptContextAction.java
@@ -45,6 +45,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get script context
+ *
+ * @opensearch.api
+ */
 public class RestGetScriptContextAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptLanguageAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptLanguageAction.java
index 4066781e8bb89..eacb9052ccab0 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptLanguageAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetScriptLanguageAction.java
@@ -45,6 +45,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get script language
+ *
+ * @opensearch.api
+ */
 public class RestGetScriptLanguageAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetSnapshotsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetSnapshotsAction.java
index 383369ce595c5..72733475e0cdd 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetSnapshotsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetSnapshotsAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,9 +49,13 @@
 
 /**
  * Returns information about snapshot
+ *
+ * @opensearch.api
  */
 public class RestGetSnapshotsAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetSnapshotsAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_snapshot/{repository}/{snapshot}"));
@@ -69,7 +74,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         GetSnapshotsRequest getSnapshotsRequest = getSnapshotsRequest(repository).snapshots(snapshots);
         getSnapshotsRequest.ignoreUnavailable(request.paramAsBoolean("ignore_unavailable", getSnapshotsRequest.ignoreUnavailable()));
         getSnapshotsRequest.verbose(request.paramAsBoolean("verbose", getSnapshotsRequest.verbose()));
-        getSnapshotsRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getSnapshotsRequest.masterNodeTimeout()));
+        getSnapshotsRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getSnapshotsRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getSnapshotsRequest, request);
         return channel -> client.admin().cluster().getSnapshots(getSnapshotsRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetStoredScriptAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetStoredScriptAction.java
index b75fb7693f865..acfadc2a5478a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetStoredScriptAction.java
@@ -33,6 +33,7 @@
 
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestStatusToXContentListener;
@@ -43,8 +44,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get stored script
+ *
+ * @opensearch.api
+ */
 public class RestGetStoredScriptAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetStoredScriptAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_scripts/{id}"));
@@ -59,7 +67,8 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, NodeClient client) throws IOException {
         String id = request.param("id");
         GetStoredScriptRequest getRequest = new GetStoredScriptRequest(id);
-        getRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getRequest.masterNodeTimeout()));
+        getRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", getRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(getRequest, request);
         return channel -> client.admin().cluster().getStoredScript(getRequest, new RestStatusToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetTaskAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetTaskAction.java
index 39ed666e71696..57a23e38a409f 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetTaskAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestGetTaskAction.java
@@ -35,10 +35,10 @@
 import org.opensearch.action.admin.cluster.node.tasks.get.GetTaskRequest;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.List;
@@ -46,6 +46,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get task
+ *
+ * @opensearch.api
+ */
 public class RestGetTaskAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestListTasksAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestListTasksAction.java
index 058a822ab5f42..ec094aa693cc9 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestListTasksAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestListTasksAction.java
@@ -32,23 +32,23 @@
 
 package org.opensearch.rest.action.admin.cluster;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 import org.opensearch.rest.action.RestToXContentListener;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 import java.util.List;
@@ -57,6 +57,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to list tasks
+ *
+ * @opensearch.api
+ */
 public class RestListTasksAction extends BaseRestHandler {
 
     private final Supplier<DiscoveryNodes> nodesInCluster;
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesHotThreadsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesHotThreadsAction.java
index 880791d2fb7e2..f505f5cdf787a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesHotThreadsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesHotThreadsAction.java
@@ -36,13 +36,13 @@
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsRequest;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestResponseListener;
 
 import java.io.IOException;
@@ -53,6 +53,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get hot threads
+ *
+ * @opensearch.api
+ */
 public class RestNodesHotThreadsAction extends BaseRestHandler {
 
     private static final String formatDeprecatedMessageWithoutNodeID = "[%s] is a deprecated endpoint. "
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoAction.java
index dbb3ef68226f6..3b83bf9d6f68c 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoAction.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.action.admin.cluster.node.info.NodesInfoRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestActions.NodesResponseRestListener;
@@ -50,6 +50,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get node info
+ *
+ * @opensearch.api
+ */
 public class RestNodesInfoAction extends BaseRestHandler {
     static final Set<String> ALLOWED_METRICS = NodesInfoRequest.Metric.allMetrics();
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesStatsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesStatsAction.java
index 3c66b0740536f..66b9afda06eb6 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesStatsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesStatsAction.java
@@ -36,7 +36,7 @@
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags.Flag;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestActions.NodesResponseRestListener;
@@ -55,6 +55,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get nodes stats
+ *
+ * @opensearch.api
+ */
 public class RestNodesStatsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesUsageAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesUsageAction.java
index f873a963ace30..6704bc975eb0b 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesUsageAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestNodesUsageAction.java
@@ -35,13 +35,13 @@
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageRequest;
 import org.opensearch.action.admin.cluster.node.usage.NodesUsageResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestActions;
 import org.opensearch.rest.action.RestBuilderListener;
 
@@ -54,6 +54,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get nodes usage
+ *
+ * @opensearch.api
+ */
 public class RestNodesUsageAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPendingClusterTasksAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPendingClusterTasksAction.java
index de80054a9afb2..a3d24bcb6e890 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPendingClusterTasksAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPendingClusterTasksAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.tasks.PendingClusterTasksRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -44,8 +45,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get pending cluster tasks
+ *
+ * @opensearch.api
+ */
 public class RestPendingClusterTasksAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPendingClusterTasksAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_cluster/pending_tasks"));
@@ -59,7 +67,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         PendingClusterTasksRequest pendingClusterTasksRequest = new PendingClusterTasksRequest();
-        pendingClusterTasksRequest.masterNodeTimeout(request.paramAsTime("master_timeout", pendingClusterTasksRequest.masterNodeTimeout()));
+        pendingClusterTasksRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", pendingClusterTasksRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(pendingClusterTasksRequest, request);
         pendingClusterTasksRequest.local(request.paramAsBoolean("local", pendingClusterTasksRequest.local()));
         return channel -> client.admin().cluster().pendingClusterTasks(pendingClusterTasksRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutRepositoryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutRepositoryAction.java
index afc4a142b689a..5ebeb668b2bec 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutRepositoryAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.admin.cluster.repositories.put.PutRepositoryRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -50,9 +51,13 @@
 
 /**
  * Registers repositories
+ *
+ * @opensearch.api
  */
 public class RestPutRepositoryAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutRepositoryAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(POST, "/_snapshot/{repository}"), new Route(PUT, "/_snapshot/{repository}")));
@@ -70,7 +75,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             putRepositoryRequest.source(parser.mapOrdered());
         }
         putRepositoryRequest.verify(request.paramAsBoolean("verify", true));
-        putRepositoryRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRepositoryRequest.masterNodeTimeout()));
+        putRepositoryRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", putRepositoryRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(putRepositoryRequest, request);
         putRepositoryRequest.timeout(request.paramAsTime("timeout", putRepositoryRequest.timeout()));
         return channel -> client.admin().cluster().putRepository(putRepositoryRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutStoredScriptAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
index f4fe21b8adbe0..e97c97d2f7989 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
@@ -33,8 +33,9 @@
 
 import org.opensearch.action.admin.cluster.storedscripts.PutStoredScriptRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,8 +49,15 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put stored script
+ *
+ * @opensearch.api
+ */
 public class RestPutStoredScriptAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutStoredScriptAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -72,11 +80,12 @@ public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client
         String id = request.param("id");
         String context = request.param("context");
         BytesReference content = request.requiredContent();
-        XContentType xContentType = request.getXContentType();
-        StoredScriptSource source = StoredScriptSource.parse(content, xContentType);
+        MediaType mediaType = request.getMediaType();
+        StoredScriptSource source = StoredScriptSource.parse(content, mediaType);
 
-        PutStoredScriptRequest putRequest = new PutStoredScriptRequest(id, context, content, request.getXContentType(), source);
-        putRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRequest.masterNodeTimeout()));
+        PutStoredScriptRequest putRequest = new PutStoredScriptRequest(id, context, content, request.getMediaType(), source);
+        putRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", putRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(putRequest, request);
         putRequest.timeout(request.paramAsTime("timeout", putRequest.timeout()));
         return channel -> client.admin().cluster().putStoredScript(putRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsAction.java
index 2d5db335ef939..ad08b373f5562 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsAction.java
@@ -36,17 +36,17 @@
 import org.opensearch.action.admin.cluster.node.reload.NodesReloadSecureSettingsRequestBuilder;
 import org.opensearch.action.admin.cluster.node.reload.NodesReloadSecureSettingsResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.settings.SecureString;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestRequestFilter;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestActions;
 import org.opensearch.rest.action.RestBuilderListener;
 
@@ -59,6 +59,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to reload secure settings
+ *
+ * @opensearch.api
+ */
 public final class RestReloadSecureSettingsAction extends BaseRestHandler implements RestRequestFilter {
 
     static final ObjectParser<NodesReloadSecureSettingsRequest, String> PARSER = new ObjectParser<>(
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteClusterInfoAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteClusterInfoAction.java
index ea6b0cd79eac9..28edba4db387d 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteClusterInfoAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteClusterInfoAction.java
@@ -44,6 +44,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get remote cluster information
+ *
+ * @opensearch.api
+ */
 public final class RestRemoteClusterInfoAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteStoreStatsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteStoreStatsAction.java
new file mode 100644
index 0000000000000..9fc2b4ab19bf1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRemoteStoreStatsAction.java
@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * Rest action for fetching remote store stats
+ *
+ * @opensearch.internal
+ */
+public class RestRemoteStoreStatsAction extends BaseRestHandler {
+
+    @Override
+    public List<Route> routes() {
+        return unmodifiableList(
+            asList(new Route(GET, "/_remotestore/stats/{index}"), new Route(GET, "/_remotestore/stats/{index}/{shard_id}"))
+        );
+    }
+
+    @Override
+    public String getName() {
+        return "remote_store_stats";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        String index = request.param("index");
+        String shardId = request.param("shard_id");
+        boolean local = Objects.equals(request.param("local"), "true");
+        RemoteStoreStatsRequest remoteStoreStatsRequest = new RemoteStoreStatsRequest();
+        if (index != null) {
+            remoteStoreStatsRequest.indices(index);
+        }
+        if (shardId != null) {
+            remoteStoreStatsRequest.shards(shardId);
+        }
+        remoteStoreStatsRequest.local(local);
+        return channel -> client.admin().cluster().remoteStoreStats(remoteStoreStatsRequest, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreRemoteStoreAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreRemoteStoreAction.java
new file mode 100644
index 0000000000000..414c82b4a470f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreRemoteStoreAction.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.remotestore.restore.RestoreRemoteStoreRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.POST;
+
+/**
+ * Restores data from remote store
+ *
+ * @opensearch.api
+ */
+public final class RestRestoreRemoteStoreAction extends BaseRestHandler {
+
+    @Override
+    public List<Route> routes() {
+        return singletonList(new Route(POST, "/_remotestore/_restore"));
+    }
+
+    @Override
+    public String getName() {
+        return "restore_remote_store_action";
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
+        RestoreRemoteStoreRequest restoreRemoteStoreRequest = new RestoreRemoteStoreRequest();
+        restoreRemoteStoreRequest.masterNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", restoreRemoteStoreRequest.masterNodeTimeout())
+        );
+        restoreRemoteStoreRequest.waitForCompletion(request.paramAsBoolean("wait_for_completion", false));
+        restoreRemoteStoreRequest.restoreAllShards(request.paramAsBoolean("restore_all_shards", false));
+        request.applyContentParser(p -> restoreRemoteStoreRequest.source(p.mapOrdered()));
+        return channel -> client.admin().cluster().restoreRemoteStore(restoreRemoteStoreRequest, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreSnapshotAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreSnapshotAction.java
index 4f6032d58b633..0fd27939dd1b6 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestRestoreSnapshotAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,9 +48,13 @@
 
 /**
  * Restores a snapshot
+ *
+ * @opensearch.api
  */
 public class RestRestoreSnapshotAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestRestoreSnapshotAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(POST, "/_snapshot/{repository}/{snapshot}/_restore"));
@@ -63,7 +68,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         RestoreSnapshotRequest restoreSnapshotRequest = restoreSnapshotRequest(request.param("repository"), request.param("snapshot"));
-        restoreSnapshotRequest.masterNodeTimeout(request.paramAsTime("master_timeout", restoreSnapshotRequest.masterNodeTimeout()));
+        restoreSnapshotRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", restoreSnapshotRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(restoreSnapshotRequest, request);
         restoreSnapshotRequest.waitForCompletion(request.paramAsBoolean("wait_for_completion", false));
         request.applyContentParser(p -> restoreSnapshotRequest.source(p.mapOrdered()));
         return channel -> client.admin().cluster().restoreSnapshot(restoreSnapshotRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestSnapshotsStatusAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestSnapshotsStatusAction.java
index a0db762a68c19..b2d4fff14a7f1 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestSnapshotsStatusAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestSnapshotsStatusAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.admin.cluster.snapshots.status.SnapshotsStatusRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,9 +50,13 @@
 
 /**
  * Returns status of currently running snapshot
+ *
+ * @opensearch.api
  */
 public class RestSnapshotsStatusAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestSnapshotsStatusAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -78,7 +83,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         SnapshotsStatusRequest snapshotsStatusRequest = snapshotsStatusRequest(repository).snapshots(snapshots);
         snapshotsStatusRequest.ignoreUnavailable(request.paramAsBoolean("ignore_unavailable", snapshotsStatusRequest.ignoreUnavailable()));
 
-        snapshotsStatusRequest.masterNodeTimeout(request.paramAsTime("master_timeout", snapshotsStatusRequest.masterNodeTimeout()));
+        snapshotsStatusRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", snapshotsStatusRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(snapshotsStatusRequest, request);
         return channel -> client.admin().cluster().snapshotsStatus(snapshotsStatusRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestVerifyRepositoryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestVerifyRepositoryAction.java
index 735325a69c2ed..f95688e6c5444 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestVerifyRepositoryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/RestVerifyRepositoryAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.cluster.repositories.verify.VerifyRepositoryRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -45,8 +46,15 @@
 import static org.opensearch.client.Requests.verifyRepositoryRequest;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to verify a repository
+ *
+ * @opensearch.api
+ */
 public class RestVerifyRepositoryAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestVerifyRepositoryAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(POST, "/_snapshot/{repository}/_verify"));
@@ -60,7 +68,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         VerifyRepositoryRequest verifyRepositoryRequest = verifyRepositoryRequest(request.param("repository"));
-        verifyRepositoryRequest.masterNodeTimeout(request.paramAsTime("master_timeout", verifyRepositoryRequest.masterNodeTimeout()));
+        verifyRepositoryRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", verifyRepositoryRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(verifyRepositoryRequest, request);
         verifyRepositoryRequest.timeout(request.paramAsTime("timeout", verifyRepositoryRequest.timeout()));
         return channel -> client.admin().cluster().verifyRepository(verifyRepositoryRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestDeleteDanglingIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestDeleteDanglingIndexAction.java
index 8024d97743cc8..47269ad376108 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestDeleteDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestDeleteDanglingIndexAction.java
@@ -35,20 +35,28 @@
 import org.opensearch.action.admin.indices.dangling.delete.DeleteDanglingIndexRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
 import java.util.List;
 
 import static java.util.Collections.singletonList;
+import static org.opensearch.core.rest.RestStatus.ACCEPTED;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
-import static org.opensearch.rest.RestStatus.ACCEPTED;
 
+/**
+ * Transport action to delete dangling index
+ *
+ * @opensearch.api
+ */
 public class RestDeleteDanglingIndexAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteDanglingIndexAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_dangling/{index_uuid}"));
@@ -67,7 +75,8 @@ public RestChannelConsumer prepareRequest(final RestRequest request, NodeClient
         );
 
         deleteRequest.timeout(request.paramAsTime("timeout", deleteRequest.timeout()));
-        deleteRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteRequest.masterNodeTimeout()));
+        deleteRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", deleteRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(deleteRequest, request);
 
         return channel -> client.admin()
             .cluster()
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestImportDanglingIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestImportDanglingIndexAction.java
index b7ba7361c2980..f81fc40d87a46 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestImportDanglingIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestImportDanglingIndexAction.java
@@ -32,22 +32,30 @@
 
 package org.opensearch.rest.action.admin.cluster.dangling;
 
-import static java.util.Collections.singletonList;
-import static org.opensearch.rest.RestRequest.Method.POST;
-import static org.opensearch.rest.RestStatus.ACCEPTED;
-
-import java.io.IOException;
-import java.util.List;
-
 import org.opensearch.action.admin.indices.dangling.import_index.ImportDanglingIndexRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.core.rest.RestStatus.ACCEPTED;
+import static org.opensearch.rest.RestRequest.Method.POST;
+
+/**
+ * Transport action to import dangling index
+ *
+ * @opensearch.api
+ */
 public class RestImportDanglingIndexAction extends BaseRestHandler {
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestImportDanglingIndexAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(POST, "/_dangling/{index_uuid}"));
@@ -66,7 +74,8 @@ public RestChannelConsumer prepareRequest(final RestRequest request, NodeClient
         );
 
         importRequest.timeout(request.paramAsTime("timeout", importRequest.timeout()));
-        importRequest.masterNodeTimeout(request.paramAsTime("master_timeout", importRequest.masterNodeTimeout()));
+        importRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", importRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(importRequest, request);
 
         return channel -> client.admin()
             .cluster()
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestListDanglingIndicesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestListDanglingIndicesAction.java
index 13b13ac29ce01..c7c18fdf3f021 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestListDanglingIndicesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/cluster/dangling/RestListDanglingIndicesAction.java
@@ -44,6 +44,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to list dangling index
+ *
+ * @opensearch.api
+ */
 public class RestListDanglingIndicesAction extends BaseRestHandler {
     @Override
     public List<Route> routes() {
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/AliasesNotFoundException.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/AliasesNotFoundException.java
index dc86cb360783c..e85df8451c836 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/AliasesNotFoundException.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/AliasesNotFoundException.java
@@ -32,11 +32,16 @@
 package org.opensearch.rest.action.admin.indices;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.Arrays;
 
+/**
+ * Exception thrown if an alias is not found
+ *
+ * @opensearch.api
+ */
 public class AliasesNotFoundException extends ResourceNotFoundException {
 
     public AliasesNotFoundException(String... names) {
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAddIndexBlockAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAddIndexBlockAction.java
index 89faeb1b7c7d9..04327d4324d52 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAddIndexBlockAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAddIndexBlockAction.java
@@ -36,7 +36,8 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,8 +48,15 @@
 
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to add index block
+ *
+ * @opensearch.api
+ */
 public class RestAddIndexBlockAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestAddIndexBlockAction.class);
+
     @Override
     public List<Route> routes() {
         return Collections.singletonList(new Route(PUT, "/{index}/_block/{block}"));
@@ -65,7 +73,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             IndexMetadata.APIBlock.fromName(request.param("block")),
             Strings.splitStringByCommaToArray(request.param("index"))
         );
-        addIndexBlockRequest.masterNodeTimeout(request.paramAsTime("master_timeout", addIndexBlockRequest.masterNodeTimeout()));
+        addIndexBlockRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", addIndexBlockRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(addIndexBlockRequest, request);
         addIndexBlockRequest.timeout(request.paramAsTime("timeout", addIndexBlockRequest.timeout()));
         addIndexBlockRequest.indicesOptions(IndicesOptions.fromRequest(request, addIndexBlockRequest.indicesOptions()));
         return channel -> client.admin().indices().addBlock(addIndexBlockRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAnalyzeAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAnalyzeAction.java
index f5b8ad7bb1864..0c64cc6ad9ec7 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAnalyzeAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestAnalyzeAction.java
@@ -33,8 +33,8 @@
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,8 +47,18 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to analyze an action
+ *
+ * @opensearch.api
+ */
 public class RestAnalyzeAction extends BaseRestHandler {
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     public static class Fields {
         public static final ParseField ANALYZER = new ParseField("analyzer");
         public static final ParseField TEXT = new ParseField("text");
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestClearIndicesCacheAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestClearIndicesCacheAction.java
index 603786c99a256..616a6ffd63433 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestClearIndicesCacheAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestClearIndicesCacheAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.cache.clear.ClearIndicesCacheRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,6 +47,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to clear indices cache
+ *
+ * @opensearch.api
+ */
 public class RestClearIndicesCacheAction extends BaseRestHandler {
 
     @Override
@@ -78,6 +83,7 @@ public static ClearIndicesCacheRequest fromRequest(final RestRequest request, Cl
         clearIndicesCacheRequest.queryCache(request.paramAsBoolean("query", clearIndicesCacheRequest.queryCache()));
         clearIndicesCacheRequest.requestCache(request.paramAsBoolean("request", clearIndicesCacheRequest.requestCache()));
         clearIndicesCacheRequest.fieldDataCache(request.paramAsBoolean("fielddata", clearIndicesCacheRequest.fieldDataCache()));
+        clearIndicesCacheRequest.fileCache(request.paramAsBoolean("file", clearIndicesCacheRequest.fileCache()));
         clearIndicesCacheRequest.fields(request.paramAsStringArray("fields", clearIndicesCacheRequest.fields()));
         return clearIndicesCacheRequest;
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCloseIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCloseIndexAction.java
index 8da0ec3c5a349..465fff02b22d2 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCloseIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCloseIndexAction.java
@@ -36,7 +36,8 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,8 +49,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to close index
+ *
+ * @opensearch.api
+ */
 public class RestCloseIndexAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestCloseIndexAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(POST, "/_close"), new Route(POST, "/{index}/_close")));
@@ -63,7 +71,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         CloseIndexRequest closeIndexRequest = new CloseIndexRequest(Strings.splitStringByCommaToArray(request.param("index")));
-        closeIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", closeIndexRequest.masterNodeTimeout()));
+        closeIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", closeIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(closeIndexRequest, request);
         closeIndexRequest.timeout(request.paramAsTime("timeout", closeIndexRequest.timeout()));
         closeIndexRequest.indicesOptions(IndicesOptions.fromRequest(request, closeIndexRequest.indicesOptions()));
         String waitForActiveShards = request.param("wait_for_active_shards");
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateDataStreamAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateDataStreamAction.java
index 92662bb78e255..a65665b99138e 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateDataStreamAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateDataStreamAction.java
@@ -41,6 +41,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Transport action to create a data stream
+ *
+ * @opensearch.api
+ */
 public class RestCreateDataStreamAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateIndexAction.java
index 5b628bc094c41..c44513453d5d2 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestCreateIndexAction.java
@@ -35,6 +35,7 @@
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.index.mapper.MapperService;
@@ -51,8 +52,15 @@
 import static java.util.Collections.singletonMap;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to create an index
+ *
+ * @opensearch.api
+ */
 public class RestCreateIndexAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestIndexPutAliasAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(PUT, "/{index}"));
@@ -68,13 +76,16 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         CreateIndexRequest createIndexRequest = new CreateIndexRequest(request.param("index"));
 
         if (request.hasContent()) {
-            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getXContentType()).v2();
+            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getMediaType()).v2();
             sourceAsMap = prepareMappings(sourceAsMap);
             createIndexRequest.source(sourceAsMap, LoggingDeprecationHandler.INSTANCE);
         }
 
         createIndexRequest.timeout(request.paramAsTime("timeout", createIndexRequest.timeout()));
-        createIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", createIndexRequest.masterNodeTimeout()));
+        createIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", createIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(createIndexRequest, request);
         createIndexRequest.waitForActiveShards(ActiveShardCount.parseString(request.param("wait_for_active_shards")));
         return channel -> client.admin().indices().create(createIndexRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDataStreamsStatsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDataStreamsStatsAction.java
index 2c7f27c5515a9..e3e549fa2c587 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDataStreamsStatsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDataStreamsStatsAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.datastream.DataStreamsStatsAction;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -44,6 +44,11 @@
 import java.util.Arrays;
 import java.util.List;
 
+/**
+ * Transport action to get data stream stats
+ *
+ * @opensearch.api
+ */
 public class RestDataStreamsStatsAction extends BaseRestHandler {
     @Override
     public String getName() {
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComponentTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComponentTemplateAction.java
index e4f0347192dbe..410ce6267a365 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComponentTemplateAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.indices.template.delete.DeleteComponentTemplateAction;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -44,8 +45,15 @@
 
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete component template
+ *
+ * @opensearch.api
+ */
 public class RestDeleteComponentTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteComponentTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Collections.singletonList(new Route(DELETE, "/_component_template/{name}"));
@@ -60,7 +68,8 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
 
         DeleteComponentTemplateAction.Request deleteReq = new DeleteComponentTemplateAction.Request(request.param("name"));
-        deleteReq.masterNodeTimeout(request.paramAsTime("master_timeout", deleteReq.masterNodeTimeout()));
+        deleteReq.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", deleteReq.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(deleteReq, request);
 
         return channel -> client.execute(DeleteComponentTemplateAction.INSTANCE, deleteReq, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComposableIndexTemplateAction.java
index f5832b4167852..84adfdde644ac 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteComposableIndexTemplateAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.admin.indices.template.delete.DeleteComposableIndexTemplateAction;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -44,8 +45,15 @@
 
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete composable index template
+ *
+ * @opensearch.api
+ */
 public class RestDeleteComposableIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteComposableIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Collections.singletonList(new Route(DELETE, "/_index_template/{name}"));
@@ -60,7 +68,8 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
 
         DeleteComposableIndexTemplateAction.Request deleteReq = new DeleteComposableIndexTemplateAction.Request(request.param("name"));
-        deleteReq.masterNodeTimeout(request.paramAsTime("master_timeout", deleteReq.masterNodeTimeout()));
+        deleteReq.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", deleteReq.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(deleteReq, request);
 
         return channel -> client.execute(DeleteComposableIndexTemplateAction.INSTANCE, deleteReq, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteDataStreamAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteDataStreamAction.java
index 40e1add973b82..cebebc63fde29 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteDataStreamAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteDataStreamAction.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.action.admin.indices.datastream.DeleteDataStreamAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -42,6 +42,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Transport action to delete data stream
+ *
+ * @opensearch.api
+ */
 public class RestDeleteDataStreamAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexAction.java
index e8b5caf8f234a..6c422f55918a2 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexAction.java
@@ -35,7 +35,8 @@
 import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,8 +48,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete index
+ *
+ * @opensearch.api
+ */
 public class RestDeleteIndexAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteIndexAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(DELETE, "/"), new Route(DELETE, "/{index}")));
@@ -63,7 +71,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest(Strings.splitStringByCommaToArray(request.param("index")));
         deleteIndexRequest.timeout(request.paramAsTime("timeout", deleteIndexRequest.timeout()));
-        deleteIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteIndexRequest.masterNodeTimeout()));
+        deleteIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", deleteIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(deleteIndexRequest, request);
         deleteIndexRequest.indicesOptions(IndicesOptions.fromRequest(request, deleteIndexRequest.indicesOptions()));
         return channel -> client.admin().indices().delete(deleteIndexRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexTemplateAction.java
index 51040082c2c47..db3b523ade671 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestDeleteIndexTemplateAction.java
@@ -33,6 +33,7 @@
 
 import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -43,8 +44,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete index template
+ *
+ * @opensearch.api
+ */
 public class RestDeleteIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeleteIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_template/{name}"));
@@ -58,7 +66,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         DeleteIndexTemplateRequest deleteIndexTemplateRequest = new DeleteIndexTemplateRequest(request.param("name"));
-        deleteIndexTemplateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", deleteIndexTemplateRequest.masterNodeTimeout()));
+        deleteIndexTemplateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", deleteIndexTemplateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(deleteIndexTemplateRequest, request);
         return channel -> client.admin().indices().deleteTemplate(deleteIndexTemplateRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestFlushAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestFlushAction.java
index 9fd88c0f4558d..59daaef33e4de 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestFlushAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestFlushAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,6 +48,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to flush
+ *
+ * @opensearch.api
+ */
 public class RestFlushAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestForceMergeAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestForceMergeAction.java
index 6e2699228012e..06f1d5f46f90b 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestForceMergeAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestForceMergeAction.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.rest.action.admin.indices;
 
+import org.opensearch.action.admin.indices.forcemerge.ForceMergeAction;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
+import org.opensearch.tasks.LoggingTaskListener;
 
 import java.io.IOException;
 import java.util.List;
@@ -48,6 +50,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to force merge
+ *
+ * @opensearch.api
+ */
 public class RestForceMergeAction extends BaseRestHandler {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestForceMergeAction.class);
@@ -75,7 +82,16 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
                 "setting only_expunge_deletes and max_num_segments at the same time is deprecated and will be rejected in a future version"
             );
         }
-        return channel -> client.admin().indices().forceMerge(mergeRequest, new RestToXContentListener<>(channel));
+        if (request.paramAsBoolean("wait_for_completion", true)) {
+            return channel -> client.admin().indices().forceMerge(mergeRequest, new RestToXContentListener<>(channel));
+        } else {
+            // running force merge asynchronously, return a task immediately and store the task's result when it completes
+            mergeRequest.setShouldStoreResult(true);
+            return sendTask(
+                client.getLocalNodeId(),
+                client.executeLocally(ForceMergeAction.INSTANCE, mergeRequest, LoggingTaskListener.instance())
+            );
+        }
     }
 
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetAliasesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetAliasesAction.java
index 4ff519e81f9cd..9225504c7d906 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetAliasesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetAliasesAction.java
@@ -32,29 +32,28 @@
 
 package org.opensearch.rest.action.admin.indices;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.io.IOException;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
@@ -66,6 +65,8 @@
 
 /**
  * The REST handler for get alias and head alias APIs.
+ *
+ * @opensearch.api
  */
 public class RestGetAliasesAction extends BaseRestHandler {
 
@@ -93,16 +94,16 @@ public String getName() {
     static RestResponse buildRestResponse(
         boolean aliasesExplicitlyRequested,
         String[] requestedAliases,
-        ImmutableOpenMap<String, List<AliasMetadata>> responseAliasMap,
+        final Map<String, List<AliasMetadata>> responseAliasMap,
         XContentBuilder builder
     ) throws Exception {
         final Set<String> indicesToDisplay = new HashSet<>();
         final Set<String> returnedAliasNames = new HashSet<>();
-        for (final ObjectObjectCursor<String, List<AliasMetadata>> cursor : responseAliasMap) {
-            for (final AliasMetadata aliasMetadata : cursor.value) {
+        for (final Map.Entry<String, List<AliasMetadata>> cursor : responseAliasMap.entrySet()) {
+            for (final AliasMetadata aliasMetadata : cursor.getValue()) {
                 if (aliasesExplicitlyRequested) {
                     // only display indices that have aliases
-                    indicesToDisplay.add(cursor.key);
+                    indicesToDisplay.add(cursor.getKey());
                 }
                 returnedAliasNames.add(aliasMetadata.alias());
             }
@@ -163,13 +164,13 @@ static RestResponse buildRestResponse(
                 builder.field("status", status.getStatus());
             }
 
-            for (final ObjectObjectCursor<String, List<AliasMetadata>> entry : responseAliasMap) {
-                if (aliasesExplicitlyRequested == false || (aliasesExplicitlyRequested && indicesToDisplay.contains(entry.key))) {
-                    builder.startObject(entry.key);
+            for (final Map.Entry<String, List<AliasMetadata>> entry : responseAliasMap.entrySet()) {
+                if (aliasesExplicitlyRequested == false || (aliasesExplicitlyRequested && indicesToDisplay.contains(entry.getKey()))) {
+                    builder.startObject(entry.getKey());
                     {
                         builder.startObject("aliases");
                         {
-                            for (final AliasMetadata alias : entry.value) {
+                            for (final AliasMetadata alias : entry.getValue()) {
                                 AliasMetadata.Builder.toXContent(alias, builder, ToXContent.EMPTY_PARAMS);
                             }
                         }
@@ -187,7 +188,7 @@ static RestResponse buildRestResponse(
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         // The TransportGetAliasesAction was improved do the same post processing as is happening here.
         // We can't remove this logic yet to support mixed clusters. We should be able to remove this logic here
-        // in when 8.0 becomes the new version in the master branch.
+        // in when 8.0 becomes the new version in the main branch.
 
         final boolean namesProvided = request.hasParam("name");
         final String[] aliases = request.paramAsStringArrayOrEmptyIfAll("name");
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComponentTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComponentTemplateAction.java
index 8a85a66eef635..c0fec9888d3b8 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComponentTemplateAction.java
@@ -34,10 +34,11 @@
 
 import org.opensearch.action.admin.indices.template.get.GetComponentTemplateAction;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
@@ -45,13 +46,20 @@
 import java.util.List;
 import java.util.Set;
 
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * Transport action to get component template
+ *
+ * @opensearch.api
+ */
 public class RestGetComponentTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetComponentTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Arrays.asList(
@@ -72,7 +80,8 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         final GetComponentTemplateAction.Request getRequest = new GetComponentTemplateAction.Request(request.param("name"));
 
         getRequest.local(request.paramAsBoolean("local", getRequest.local()));
-        getRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getRequest.masterNodeTimeout()));
+        getRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", getRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(getRequest, request);
 
         final boolean implicitAll = getRequest.name() == null;
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComposableIndexTemplateAction.java
index 684198c6799f0..3a66eef8be39f 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetComposableIndexTemplateAction.java
@@ -34,10 +34,11 @@
 
 import org.opensearch.action.admin.indices.template.get.GetComposableIndexTemplateAction;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
@@ -45,13 +46,20 @@
 import java.util.List;
 import java.util.Set;
 
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * Transport action to get composable index template
+ *
+ * @opensearch.api
+ */
 public class RestGetComposableIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetComposableIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Arrays.asList(
@@ -71,7 +79,8 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         final GetComposableIndexTemplateAction.Request getRequest = new GetComposableIndexTemplateAction.Request(request.param("name"));
 
         getRequest.local(request.paramAsBoolean("local", getRequest.local()));
-        getRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getRequest.masterNodeTimeout()));
+        getRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", getRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(getRequest, request);
 
         final boolean implicitAll = getRequest.name() == null;
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetDataStreamsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetDataStreamsAction.java
index 539ad671e5fd3..2c7a8398a34c6 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetDataStreamsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetDataStreamsAction.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.action.admin.indices.datastream.GetDataStreamAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport action to get data streams
+ *
+ * @opensearch.api
+ */
 public class RestGetDataStreamsAction extends BaseRestHandler {
 
     @Override
@@ -50,10 +55,7 @@ public String getName() {
 
     @Override
     public List<Route> routes() {
-        return org.opensearch.common.collect.List.of(
-            new Route(RestRequest.Method.GET, "/_data_stream"),
-            new Route(RestRequest.Method.GET, "/_data_stream/{name}")
-        );
+        return List.of(new Route(RestRequest.Method.GET, "/_data_stream"), new Route(RestRequest.Method.GET, "/_data_stream/{name}"));
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetFieldMappingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetFieldMappingAction.java
index c35f417795377..0aa1fbbfc7540 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetFieldMappingAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetFieldMappingAction.java
@@ -39,14 +39,14 @@
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsResponse.FieldMappingMetadata;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 
 import java.io.IOException;
@@ -55,10 +55,15 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * Transport action to get field mapping
+ *
+ * @opensearch.api
+ */
 public class RestGetFieldMappingAction extends BaseRestHandler {
     private static final Logger logger = LogManager.getLogger(RestGetFieldMappingAction.class);
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(logger.getName());
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndexTemplateAction.java
index 71e7ed098cf8d..05dcbd82b4952 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndexTemplateAction.java
@@ -35,11 +35,12 @@
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesRequest;
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
@@ -48,16 +49,20 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
 
 /**
  * The REST handler for get template and head template APIs.
+ *
+ * @opensearch.api
  */
 public class RestGetIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -76,7 +81,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
 
         final GetIndexTemplatesRequest getIndexTemplatesRequest = new GetIndexTemplatesRequest(names);
         getIndexTemplatesRequest.local(request.paramAsBoolean("local", getIndexTemplatesRequest.local()));
-        getIndexTemplatesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getIndexTemplatesRequest.masterNodeTimeout()));
+        getIndexTemplatesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getIndexTemplatesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getIndexTemplatesRequest, request);
 
         final boolean implicitAll = getIndexTemplatesRequest.names().length == 0;
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndicesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndicesAction.java
index 37c8162c6d31b..7c62d125ef43a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndicesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetIndicesAction.java
@@ -35,8 +35,9 @@
 import org.opensearch.action.admin.indices.get.GetIndexRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -52,9 +53,13 @@
 
 /**
  * The REST handler for get index and head index APIs.
+ *
+ * @opensearch.api
  */
 public class RestGetIndicesAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetIndicesAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/{index}"), new Route(HEAD, "/{index}")));
@@ -72,7 +77,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         getIndexRequest.indices(indices);
         getIndexRequest.indicesOptions(IndicesOptions.fromRequest(request, getIndexRequest.indicesOptions()));
         getIndexRequest.local(request.paramAsBoolean("local", getIndexRequest.local()));
-        getIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getIndexRequest.masterNodeTimeout()));
+        getIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getIndexRequest, request);
         getIndexRequest.humanReadable(request.paramAsBoolean("human", false));
         getIndexRequest.includeDefaults(request.paramAsBoolean("include_defaults", false));
         return channel -> client.admin().indices().getIndex(getIndexRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetMappingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetMappingAction.java
index f4f33905408e7..5f3828d9ebd30 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetMappingAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetMappingAction.java
@@ -32,20 +32,21 @@
 
 package org.opensearch.rest.action.admin.indices;
 
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsRequest;
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestActionListener;
 import org.opensearch.rest.action.RestBuilderListener;
 import org.opensearch.threadpool.ThreadPool;
@@ -57,6 +58,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get mapping
+ *
+ * @opensearch.api
+ */
 public class RestGetMappingAction extends BaseRestHandler {
 
     private final ThreadPool threadPool;
@@ -89,8 +95,16 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         final GetMappingsRequest getMappingsRequest = new GetMappingsRequest();
         getMappingsRequest.indices(indices);
         getMappingsRequest.indicesOptions(IndicesOptions.fromRequest(request, getMappingsRequest.indicesOptions()));
-        final TimeValue timeout = request.paramAsTime("master_timeout", getMappingsRequest.masterNodeTimeout());
-        getMappingsRequest.masterNodeTimeout(timeout);
+        TimeValue clusterManagerTimeout = request.paramAsTime("cluster_manager_timeout", getMappingsRequest.clusterManagerNodeTimeout());
+        // Remove the if condition and statements inside after removing MASTER_ROLE.
+        if (request.hasParam("master_timeout")) {
+            if (request.hasParam("cluster_manager_timeout")) {
+                throw new OpenSearchParseException(DUPLICATE_PARAMETER_ERROR_MESSAGE);
+            }
+            clusterManagerTimeout = request.paramAsTime("master_timeout", getMappingsRequest.clusterManagerNodeTimeout());
+        }
+        final TimeValue timeout = clusterManagerTimeout;
+        getMappingsRequest.clusterManagerNodeTimeout(timeout);
         getMappingsRequest.local(request.paramAsBoolean("local", getMappingsRequest.local()));
         return channel -> client.admin().indices().getMappings(getMappingsRequest, new RestActionListener<GetMappingsResponse>(channel) {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetSettingsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetSettingsAction.java
index 589bdfdbe79dd..827d315173881 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetSettingsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestGetSettingsAction.java
@@ -35,7 +35,8 @@
 import org.opensearch.action.admin.indices.settings.get.GetSettingsRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,8 +48,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get settings
+ *
+ * @opensearch.api
+ */
 public class RestGetSettingsAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetSettingsAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -79,7 +87,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             .includeDefaults(renderDefaults)
             .names(names);
         getSettingsRequest.local(request.paramAsBoolean("local", getSettingsRequest.local()));
-        getSettingsRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getSettingsRequest.masterNodeTimeout()));
+        getSettingsRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getSettingsRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getSettingsRequest, request);
         return channel -> client.admin().indices().getSettings(getSettingsRequest, new RestToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexDeleteAliasesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexDeleteAliasesAction.java
index 6a8098dfaf633..830a3db599df7 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexDeleteAliasesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexDeleteAliasesAction.java
@@ -34,7 +34,8 @@
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -46,8 +47,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete index aliases
+ *
+ * @opensearch.api
+ */
 public class RestIndexDeleteAliasesAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestIndexPutAliasAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(DELETE, "/{index}/_alias/{name}"), new Route(DELETE, "/{index}/_aliases/{name}")));
@@ -65,7 +73,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         IndicesAliasesRequest indicesAliasesRequest = new IndicesAliasesRequest();
         indicesAliasesRequest.timeout(request.paramAsTime("timeout", indicesAliasesRequest.timeout()));
         indicesAliasesRequest.addAliasAction(AliasActions.remove().indices(indices).aliases(aliases));
-        indicesAliasesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", indicesAliasesRequest.masterNodeTimeout()));
+        indicesAliasesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", indicesAliasesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(indicesAliasesRequest, request);
 
         return channel -> client.admin().indices().aliases(indicesAliasesRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexPutAliasAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexPutAliasAction.java
index cc31dc1117946..9253763c53fb8 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexPutAliasAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndexPutAliasAction.java
@@ -34,8 +34,9 @@
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,8 +50,15 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put alias(es)
+ *
+ * @opensearch.api
+ */
 public class RestIndexPutAliasAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestIndexPutAliasAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -124,7 +132,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
 
         IndicesAliasesRequest indicesAliasesRequest = new IndicesAliasesRequest();
         indicesAliasesRequest.timeout(request.paramAsTime("timeout", indicesAliasesRequest.timeout()));
-        indicesAliasesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", indicesAliasesRequest.masterNodeTimeout()));
+        indicesAliasesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", indicesAliasesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(indicesAliasesRequest, request);
 
         IndicesAliasesRequest.AliasActions aliasAction = AliasActions.add().indices(indices).alias(alias);
         if (routing != null) {
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesAliasesAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesAliasesAction.java
index 138343a2e7335..b37126b9f2a8a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesAliasesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesAliasesAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -45,8 +46,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to list alias(es)
+ *
+ * @opensearch.api
+ */
 public class RestIndicesAliasesAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestIndicesAliasesAction.class);
+
     @Override
     public String getName() {
         return "indices_aliases_action";
@@ -60,7 +68,10 @@ public List<Route> routes() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         IndicesAliasesRequest indicesAliasesRequest = new IndicesAliasesRequest();
-        indicesAliasesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", indicesAliasesRequest.masterNodeTimeout()));
+        indicesAliasesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", indicesAliasesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(indicesAliasesRequest, request);
         indicesAliasesRequest.timeout(request.paramAsTime("timeout", indicesAliasesRequest.timeout()));
         try (XContentParser parser = request.contentParser()) {
             IndicesAliasesRequest.PARSER.parse(parser, indicesAliasesRequest, null);
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesSegmentsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesSegmentsAction.java
index c635c8928bafd..f263158abcb7b 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesSegmentsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesSegmentsAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.segments.IndicesSegmentsRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,6 +47,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get segment information
+ *
+ * @opensearch.api
+ */
 public class RestIndicesSegmentsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesShardStoresAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesShardStoresAction.java
index 6030fad4e8501..4e9d1397ef11a 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesShardStoresAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesShardStoresAction.java
@@ -37,8 +37,8 @@
 import org.opensearch.action.admin.indices.shards.IndicesShardStoresResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
@@ -50,11 +50,13 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
-import static org.opensearch.rest.RestStatus.OK;
 
 /**
  * Rest action for {@link IndicesShardStoresAction}
+ *
+ * @opensearch.api
  */
 public class RestIndicesShardStoresAction extends BaseRestHandler {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesStatsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesStatsAction.java
index eabe14a7614ac..d370fa074aaed 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesStatsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestIndicesStatsAction.java
@@ -37,7 +37,7 @@
 import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -56,6 +56,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get indices stats
+ *
+ * @opensearch.api
+ */
 public class RestIndicesStatsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestOpenIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestOpenIndexAction.java
index 4b6450c35233f..34c1f0b725ec3 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestOpenIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestOpenIndexAction.java
@@ -32,24 +32,36 @@
 
 package org.opensearch.rest.action.admin.indices;
 
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.indices.open.OpenIndexAction;
 import org.opensearch.action.admin.indices.open.OpenIndexRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
+import org.opensearch.tasks.LoggingTaskListener;
 
 import java.io.IOException;
 import java.util.List;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.action.support.master.AcknowledgedRequest.DEFAULT_TASK_EXECUTION_TIMEOUT;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to open an index
+ *
+ * @opensearch.api
+ */
 public class RestOpenIndexAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestOpenIndexAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(POST, "/_open"), new Route(POST, "/{index}/_open")));
@@ -64,12 +76,38 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         OpenIndexRequest openIndexRequest = new OpenIndexRequest(Strings.splitStringByCommaToArray(request.param("index")));
         openIndexRequest.timeout(request.paramAsTime("timeout", openIndexRequest.timeout()));
-        openIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", openIndexRequest.masterNodeTimeout()));
+        openIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", openIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(openIndexRequest, request);
         openIndexRequest.indicesOptions(IndicesOptions.fromRequest(request, openIndexRequest.indicesOptions()));
         String waitForActiveShards = request.param("wait_for_active_shards");
         if (waitForActiveShards != null) {
             openIndexRequest.waitForActiveShards(ActiveShardCount.parseString(waitForActiveShards));
         }
-        return channel -> client.admin().indices().open(openIndexRequest, new RestToXContentListener<>(channel));
+        if (request.paramAsBoolean("wait_for_completion", true)) {
+            return channel -> client.admin().indices().open(openIndexRequest, new RestToXContentListener<>(channel));
+        } else {
+            // Running opening index asynchronously, return a task immediately and store the task's result when it completes
+            openIndexRequest.setShouldStoreResult(true);
+            /*
+             * Replace the ack timeout by task_execution_timeout so that the task can take a longer time to execute but not finish in 30s
+             * by default, task_execution_timeout defaults to 1h.
+             */
+            openIndexRequest.timeout(request.paramAsTime("task_execution_timeout", DEFAULT_TASK_EXECUTION_TIMEOUT));
+            /*
+             * Add some validation before so the user can get some error immediately. The
+             * task can't totally validate until it starts but this is better than nothing.
+             */
+            ActionRequestValidationException validationException = openIndexRequest.validate();
+            if (validationException != null) {
+                throw validationException;
+            }
+            return sendTask(
+                client.getLocalNodeId(),
+                client.executeLocally(OpenIndexAction.INSTANCE, openIndexRequest, LoggingTaskListener.instance())
+            );
+        }
+
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComponentTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComponentTemplateAction.java
index ab02eef51a072..15f4ba36694fd 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComponentTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComponentTemplateAction.java
@@ -35,6 +35,7 @@
 import org.opensearch.action.admin.indices.template.put.PutComponentTemplateAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.ComponentTemplate;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -46,8 +47,15 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put component template
+ *
+ * @opensearch.api
+ */
 public class RestPutComponentTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutComponentTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Arrays.asList(new Route(POST, "/_component_template/{name}"), new Route(PUT, "/_component_template/{name}"));
@@ -62,7 +70,8 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
 
         PutComponentTemplateAction.Request putRequest = new PutComponentTemplateAction.Request(request.param("name"));
-        putRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRequest.masterNodeTimeout()));
+        putRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", putRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(putRequest, request);
         putRequest.create(request.paramAsBoolean("create", false));
         putRequest.cause(request.param("cause", "api"));
         putRequest.componentTemplate(ComponentTemplate.parse(request.contentParser()));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComposableIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComposableIndexTemplateAction.java
index 790aad33008b9..5ba0d90681b29 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComposableIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutComposableIndexTemplateAction.java
@@ -35,6 +35,7 @@
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -46,8 +47,15 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put composable index templates
+ *
+ * @opensearch.api
+ */
 public class RestPutComposableIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutComposableIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Arrays.asList(new Route(POST, "/_index_template/{name}"), new Route(PUT, "/_index_template/{name}"));
@@ -62,7 +70,8 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
 
         PutComposableIndexTemplateAction.Request putRequest = new PutComposableIndexTemplateAction.Request(request.param("name"));
-        putRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRequest.masterNodeTimeout()));
+        putRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", putRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(putRequest, request);
         putRequest.create(request.paramAsBoolean("create", false));
         putRequest.cause(request.param("cause", "api"));
         putRequest.indexTemplate(ComposableIndexTemplate.parse(request.contentParser()));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
index f17ac495b494b..785f75085f184 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.action.admin.indices.template.put.PutIndexTemplateRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -52,6 +52,11 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put index template
+ *
+ * @opensearch.api
+ */
 public class RestPutIndexTemplateAction extends BaseRestHandler {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutIndexTemplateAction.class);
 
@@ -78,11 +83,12 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             putRequest.patterns(Arrays.asList(request.paramAsStringArray("index_patterns", Strings.EMPTY_ARRAY)));
         }
         putRequest.order(request.paramAsInt("order", putRequest.order()));
-        putRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRequest.masterNodeTimeout()));
+        putRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", putRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(putRequest, request);
         putRequest.create(request.paramAsBoolean("create", false));
         putRequest.cause(request.param("cause", ""));
 
-        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getXContentType()).v2();
+        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getMediaType()).v2();
         sourceAsMap = RestCreateIndexAction.prepareMappings(sourceAsMap);
         putRequest.source(sourceAsMap);
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutMappingAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutMappingAction.java
index f65dea1ebe3d2..1e646cee7232e 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutMappingAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestPutMappingAction.java
@@ -35,8 +35,9 @@
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -52,8 +53,15 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put mapping
+ *
+ * @opensearch.api
+ */
 public class RestPutMappingAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutMappingAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(
@@ -75,7 +83,7 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
 
         PutMappingRequest putMappingRequest = putMappingRequest(Strings.splitStringByCommaToArray(request.param("index")));
-        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getXContentType()).v2();
+        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(request.requiredContent(), false, request.getMediaType()).v2();
 
         if (MapperService.isMappingSourceTyped(MapperService.SINGLE_MAPPING_NAME, sourceAsMap)) {
             throw new IllegalArgumentException("Types cannot be provided in put mapping requests");
@@ -83,7 +91,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
 
         putMappingRequest.source(sourceAsMap);
         putMappingRequest.timeout(request.paramAsTime("timeout", putMappingRequest.timeout()));
-        putMappingRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putMappingRequest.masterNodeTimeout()));
+        putMappingRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", putMappingRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(putMappingRequest, request);
         putMappingRequest.indicesOptions(IndicesOptions.fromRequest(request, putMappingRequest.indicesOptions()));
         putMappingRequest.writeIndexOnly(request.paramAsBoolean("write_index_only", false));
         return channel -> client.admin().indices().putMapping(putMappingRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRecoveryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRecoveryAction.java
index 75e3bcc97c68e..768e31d854200 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRecoveryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRecoveryAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.recovery.RecoveryRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,6 +49,8 @@
 
 /**
  * REST handler to report on index recoveries.
+ *
+ * @opensearch.api
  */
 public class RestRecoveryAction extends BaseRestHandler {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRefreshAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRefreshAction.java
index 28acfce57e3f3..d16587312a6b7 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRefreshAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRefreshAction.java
@@ -36,10 +36,10 @@
 import org.opensearch.action.admin.indices.refresh.RefreshResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
@@ -50,6 +50,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to refresh
+ *
+ * @opensearch.api
+ */
 public class RestRefreshAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResizeHandler.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResizeHandler.java
index a0d479890f2d0..897df9d5e9025 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResizeHandler.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResizeHandler.java
@@ -35,6 +35,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.indices.shrink.ResizeAction;
 import org.opensearch.action.admin.indices.shrink.ResizeRequest;
 import org.opensearch.action.admin.indices.shrink.ResizeType;
 import org.opensearch.action.support.ActiveShardCount;
@@ -44,15 +46,22 @@
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
+import org.opensearch.tasks.LoggingTaskListener;
 
 import java.io.IOException;
 import java.util.List;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.action.support.master.AcknowledgedRequest.DEFAULT_TASK_EXECUTION_TIMEOUT;
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport handler to resize indices
+ *
+ * @opensearch.api
+ */
 public abstract class RestResizeHandler extends BaseRestHandler {
     private static final Logger logger = LogManager.getLogger(RestResizeHandler.class);
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(logger.getName());
@@ -85,17 +94,47 @@ public final RestChannelConsumer prepareRequest(final RestRequest request, final
             }
             deprecationLogger.deprecate(
                 "resize_deprecated_parameter",
-                "parameter [copy_settings] is deprecated and will be removed in 8.0.0"
+                "parameter [copy_settings] is deprecated and will be removed in 3.0.0"
             );
         }
         resizeRequest.setCopySettings(copySettings);
         request.applyContentParser(resizeRequest::fromXContent);
         resizeRequest.timeout(request.paramAsTime("timeout", resizeRequest.timeout()));
-        resizeRequest.masterNodeTimeout(request.paramAsTime("master_timeout", resizeRequest.masterNodeTimeout()));
+        resizeRequest.getTargetIndexRequest().timeout(resizeRequest.timeout());
+        resizeRequest.clusterManagerNodeTimeout(request.paramAsTime("cluster_manager_timeout", resizeRequest.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(resizeRequest, request);
+        resizeRequest.getTargetIndexRequest().clusterManagerNodeTimeout(resizeRequest.clusterManagerNodeTimeout());
         resizeRequest.setWaitForActiveShards(ActiveShardCount.parseString(request.param("wait_for_active_shards")));
-        return channel -> client.admin().indices().resizeIndex(resizeRequest, new RestToXContentListener<>(channel));
+        if (request.paramAsBoolean("wait_for_completion", true)) {
+            return channel -> client.admin().indices().resizeIndex(resizeRequest, new RestToXContentListener<>(channel));
+        } else {
+            // running resizing index asynchronously, return a task immediately and store the task's result when it completes
+            resizeRequest.setShouldStoreResult(true);
+            /*
+             * Replace the ack timeout by task_execution_timeout so that the task can take a longer time to execute but not finish in 30s
+             * by default, task_execution_timeout defaults to 1h.
+             */
+            resizeRequest.getTargetIndexRequest().timeout(request.paramAsTime("task_execution_timeout", DEFAULT_TASK_EXECUTION_TIMEOUT));
+            /*
+             * Add some validation before so the user can get some error immediately. The
+             * task can't totally validate until it starts but this is better than nothing.
+             */
+            ActionRequestValidationException validationException = resizeRequest.validate();
+            if (validationException != null) {
+                throw validationException;
+            }
+            return sendTask(
+                client.getLocalNodeId(),
+                client.executeLocally(ResizeAction.INSTANCE, resizeRequest, LoggingTaskListener.instance())
+            );
+        }
     }
 
+    /**
+     * Shrink index action.
+     *
+     * @opensearch.internal
+     */
     public static class RestShrinkIndexAction extends RestResizeHandler {
 
         @Override
@@ -115,6 +154,11 @@ protected ResizeType getResizeType() {
 
     }
 
+    /**
+     * Split index action.
+     *
+     * @opensearch.internal
+     */
     public static class RestSplitIndexAction extends RestResizeHandler {
 
         @Override
@@ -134,6 +178,11 @@ protected ResizeType getResizeType() {
 
     }
 
+    /**
+     * Clone index action.
+     *
+     * @opensearch.internal
+     */
     public static class RestCloneIndexAction extends RestResizeHandler {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResolveIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResolveIndexAction.java
index c4d96ca74492d..2feca44c95a85 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResolveIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestResolveIndexAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -43,6 +43,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Transport action to resolve index
+ *
+ * @opensearch.api
+ */
 public class RestResolveIndexAction extends BaseRestHandler {
 
     @Override
@@ -52,7 +57,7 @@ public String getName() {
 
     @Override
     public List<Route> routes() {
-        return org.opensearch.common.collect.List.of(new Route(RestRequest.Method.GET, "/_resolve/index/{name}"));
+        return List.of(new Route(RestRequest.Method.GET, "/_resolve/index/{name}"));
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRolloverIndexAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRolloverIndexAction.java
index 08b84cc6fe6cc..4f84e235a098c 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRolloverIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestRolloverIndexAction.java
@@ -47,6 +47,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to rollover index
+ *
+ * @opensearch.api
+ */
 public class RestRolloverIndexAction extends BaseRestHandler {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestRolloverIndexAction.class);
@@ -72,7 +77,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         request.applyContentParser(parser -> rolloverIndexRequest.fromXContent(parser));
         rolloverIndexRequest.dryRun(request.paramAsBoolean("dry_run", false));
         rolloverIndexRequest.timeout(request.paramAsTime("timeout", rolloverIndexRequest.timeout()));
-        rolloverIndexRequest.masterNodeTimeout(request.paramAsTime("master_timeout", rolloverIndexRequest.masterNodeTimeout()));
+        rolloverIndexRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", rolloverIndexRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(rolloverIndexRequest, request);
         rolloverIndexRequest.getCreateIndexRequest()
             .waitForActiveShards(ActiveShardCount.parseString(request.param("wait_for_active_shards")));
         return channel -> client.admin().indices().rolloverIndex(rolloverIndexRequest, new RestToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateIndexTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateIndexTemplateAction.java
index 596b96c28be41..edb3f12f339ba 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateIndexTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateIndexTemplateAction.java
@@ -37,6 +37,7 @@
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -46,11 +47,18 @@
 
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to simulate an index template
+ *
+ * @opensearch.api
+ */
 public class RestSimulateIndexTemplateAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestSimulateIndexTemplateAction.class);
+
     @Override
     public List<Route> routes() {
-        return org.opensearch.common.collect.List.of(new Route(POST, "/_index_template/_simulate_index/{name}"));
+        return List.of(new Route(POST, "/_index_template/_simulate_index/{name}"));
     }
 
     @Override
@@ -61,9 +69,10 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         SimulateIndexTemplateRequest simulateIndexTemplateRequest = new SimulateIndexTemplateRequest(request.param("name"));
-        simulateIndexTemplateRequest.masterNodeTimeout(
-            request.paramAsTime("master_timeout", simulateIndexTemplateRequest.masterNodeTimeout())
+        simulateIndexTemplateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", simulateIndexTemplateRequest.clusterManagerNodeTimeout())
         );
+        parseDeprecatedMasterTimeoutParameter(simulateIndexTemplateRequest, request);
         if (request.hasContent()) {
             PutComposableIndexTemplateAction.Request indexTemplateRequest = new PutComposableIndexTemplateAction.Request(
                 "simulating_template"
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateTemplateAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateTemplateAction.java
index c3f0958f62718..b1dda09928dca 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateTemplateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSimulateTemplateAction.java
@@ -36,6 +36,7 @@
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -46,7 +47,14 @@
 
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to simulate a template
+ *
+ * @opensearch.api
+ */
 public class RestSimulateTemplateAction extends BaseRestHandler {
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestSimulateTemplateAction.class);
+
     @Override
     public List<Route> routes() {
         return Arrays.asList(new Route(POST, "/_index_template/_simulate"), new Route(POST, "/_index_template/_simulate/{name}"));
@@ -58,7 +66,7 @@ public String getName() {
     }
 
     @Override
-    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+    public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
         SimulateTemplateAction.Request simulateRequest = new SimulateTemplateAction.Request();
         simulateRequest.templateName(request.param("name"));
         if (request.hasContent()) {
@@ -71,7 +79,10 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
 
             simulateRequest.indexTemplateRequest(indexTemplateRequest);
         }
-        simulateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", simulateRequest.masterNodeTimeout()));
+        simulateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", simulateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(simulateRequest, request);
 
         return channel -> client.execute(SimulateTemplateAction.INSTANCE, simulateRequest, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSyncedFlushAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSyncedFlushAction.java
index 726fd69dc29c1..3b7c254b21aae 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSyncedFlushAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestSyncedFlushAction.java
@@ -36,15 +36,15 @@
 import org.opensearch.action.admin.indices.flush.FlushResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
@@ -55,6 +55,14 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to execute a synced flush
+ *
+ * @opensearch.api
+ *
+ * @deprecated remove since synced flush is removed
+ */
+@Deprecated
 public class RestSyncedFlushAction extends BaseRestHandler {
 
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(RestSyncedFlushAction.class);
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpdateSettingsAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpdateSettingsAction.java
index 8356901dbc7ab..b229fa2eccb2c 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpdateSettingsAction.java
@@ -35,8 +35,9 @@
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -50,8 +51,15 @@
 import static org.opensearch.client.Requests.updateSettingsRequest;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to update settings
+ *
+ * @opensearch.api
+ */
 public class RestUpdateSettingsAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestUpdateSettingsAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(PUT, "/{index}/_settings"), new Route(PUT, "/_settings")));
@@ -67,7 +75,10 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         UpdateSettingsRequest updateSettingsRequest = updateSettingsRequest(Strings.splitStringByCommaToArray(request.param("index")));
         updateSettingsRequest.timeout(request.paramAsTime("timeout", updateSettingsRequest.timeout()));
         updateSettingsRequest.setPreserveExisting(request.paramAsBoolean("preserve_existing", updateSettingsRequest.isPreserveExisting()));
-        updateSettingsRequest.masterNodeTimeout(request.paramAsTime("master_timeout", updateSettingsRequest.masterNodeTimeout()));
+        updateSettingsRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", updateSettingsRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(updateSettingsRequest, request);
         updateSettingsRequest.indicesOptions(IndicesOptions.fromRequest(request, updateSettingsRequest.indicesOptions()));
         updateSettingsRequest.fromXContent(request.contentParser());
 
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeAction.java
index ba9dc76517852..4f53fde259454 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.upgrade.post.UpgradeRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,6 +47,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to upgrade an index
+ *
+ * @opensearch.api
+ */
 public class RestUpgradeAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeStatusAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeStatusAction.java
index d5582fa5c4414..79c8ada440df6 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeStatusAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestUpgradeStatusAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.admin.indices.upgrade.get.UpgradeStatusRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,6 +47,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get an upgrade status
+ *
+ * @opensearch.api
+ */
 public class RestUpgradeStatusAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestValidateQueryAction.java b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestValidateQueryAction.java
index bf300d5395b79..7aebcb6e6301b 100644
--- a/server/src/main/java/org/opensearch/rest/action/admin/indices/RestValidateQueryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/admin/indices/RestValidateQueryAction.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
@@ -52,10 +52,15 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * Transport action to validate a query
+ *
+ * @opensearch.api
+ */
 public class RestValidateQueryAction extends BaseRestHandler {
     @Override
     public List<Route> routes() {
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/AbstractCatAction.java b/server/src/main/java/org/opensearch/rest/action/cat/AbstractCatAction.java
index d82a32cfc2c5d..6f4e060363bfb 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/AbstractCatAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/AbstractCatAction.java
@@ -35,11 +35,11 @@
 import org.opensearch.common.Table;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.UTF8StreamWriter;
-import org.opensearch.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -50,6 +50,11 @@
 import static org.opensearch.rest.action.cat.RestTable.buildHelpWidths;
 import static org.opensearch.rest.action.cat.RestTable.pad;
 
+/**
+ * Base Transport action class for _cat API
+ *
+ * @opensearch.api
+ */
 public abstract class AbstractCatAction extends BaseRestHandler {
 
     protected abstract RestChannelConsumer doCatRequest(RestRequest request, NodeClient client);
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestAliasAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestAliasAction.java
index 78e0134fe0bda..4600dddbb361d 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestAliasAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestAliasAction.java
@@ -31,24 +31,29 @@
 
 package org.opensearch.rest.action.cat;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestResponseListener;
 
 import java.util.List;
+import java.util.Map;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to list aliases
+ *
+ * @opensearch.api
+ */
 public class RestAliasAction extends AbstractCatAction {
 
     @Override
@@ -106,9 +111,9 @@ protected Table getTableWithHeader(RestRequest request) {
     private Table buildTable(RestRequest request, GetAliasesResponse response) {
         Table table = getTableWithHeader(request);
 
-        for (ObjectObjectCursor<String, List<AliasMetadata>> cursor : response.getAliases()) {
-            String indexName = cursor.key;
-            for (AliasMetadata aliasMetadata : cursor.value) {
+        for (final Map.Entry<String, List<AliasMetadata>> cursor : response.getAliases().entrySet()) {
+            String indexName = cursor.getKey();
+            for (AliasMetadata aliasMetadata : cursor.getValue()) {
                 table.startRow();
                 table.addCell(aliasMetadata.alias());
                 table.addCell(indexName);
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestAllocationAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestAllocationAction.java
index a74d64d1530c5..46e303c9667fc 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestAllocationAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestAllocationAction.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.rest.action.cat;
 
-import com.carrotsearch.hppc.ObjectIntScatterMap;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -42,22 +41,32 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestActionListener;
 import org.opensearch.rest.action.RestResponseListener;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to list shard allocations
+ *
+ * @opensearch.api
+ */
 public class RestAllocationAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestAllocationAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/allocation"), new Route(GET, "/_cat/allocation/{nodes}")));
@@ -79,7 +88,10 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear().routingTable(true);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
             @Override
@@ -120,7 +132,7 @@ protected Table getTableWithHeader(final RestRequest request) {
     }
 
     private Table buildTable(RestRequest request, final ClusterStateResponse state, final NodesStatsResponse stats) {
-        final ObjectIntScatterMap<String> allocs = new ObjectIntScatterMap<>();
+        final Map<String, Integer> allocs = new HashMap<>();
 
         for (ShardRouting shard : state.getState().routingTable().allShards()) {
             String nodeId = "UNASSIGNED";
@@ -129,7 +141,7 @@ private Table buildTable(RestRequest request, final ClusterStateResponse state,
                 nodeId = shard.currentNodeId();
             }
 
-            allocs.addTo(nodeId, 1);
+            allocs.merge(nodeId, 1, Integer::sum);
         }
 
         Table table = getTableWithHeader(request);
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestCatAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestCatAction.java
index 2aaccdbdf6bf5..b6e1b0e99fa2c 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestCatAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestCatAction.java
@@ -33,10 +33,10 @@
 package org.opensearch.rest.action.cat;
 
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.List;
@@ -44,6 +44,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Base _cat API endpoint
+ *
+ * @opensearch.api
+ */
 public class RestCatAction extends BaseRestHandler {
 
     private static final String CAT = "=^.^=";
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestCatRecoveryAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestCatRecoveryAction.java
index 2dd7a2fddbf58..4f95e10ae3622 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestCatRecoveryAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestCatRecoveryAction.java
@@ -39,10 +39,10 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentOpenSearchExtension;
+import org.opensearch.core.common.Strings;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -60,6 +60,8 @@
  * RestRecoveryAction provides information about the status of replica recovery
  * in a string format, designed to be used at the command line. An Index can
  * be specified to limit output to a particular index or indices.
+ *
+ * @opensearch.api
  */
 public class RestCatRecoveryAction extends AbstractCatAction {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationAction.java
new file mode 100644
index 0000000000000..cba42156deead
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationAction.java
@@ -0,0 +1,202 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.cat;
+
+import org.apache.lucene.util.CollectionUtil;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsRequest;
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.Table;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.xcontent.XContentOpenSearchExtension;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestResponse;
+import org.opensearch.rest.action.RestResponseListener;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * RestCatSegmentReplicationAction provides information about the status of replica's segment replication event
+ * in a string format, designed to be used at the command line. An Index can
+ * be specified to limit output to a particular index or indices.
+ *
+ * @opensearch.api
+ */
+public class RestCatSegmentReplicationAction extends AbstractCatAction {
+    @Override
+    public List<RestHandler.Route> routes() {
+        return unmodifiableList(
+            asList(new RestHandler.Route(GET, "/_cat/segment_replication"), new RestHandler.Route(GET, "/_cat/segment_replication/{index}"))
+        );
+    }
+
+    @Override
+    public String getName() {
+        return "cat_segment_replication_action";
+    }
+
+    @Override
+    protected void documentation(StringBuilder sb) {
+        sb.append("/_cat/segment_replication\n");
+        sb.append("/_cat/segment_replication/{index}\n");
+    }
+
+    @Override
+    public BaseRestHandler.RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
+        final SegmentReplicationStatsRequest segmentReplicationStatsRequest = new SegmentReplicationStatsRequest(
+            Strings.splitStringByCommaToArray(request.param("index"))
+        );
+        segmentReplicationStatsRequest.timeout(request.param("timeout"));
+        segmentReplicationStatsRequest.detailed(request.paramAsBoolean("detailed", false));
+        segmentReplicationStatsRequest.shards(Strings.splitStringByCommaToArray(request.param("shards")));
+        segmentReplicationStatsRequest.activeOnly(request.paramAsBoolean("active_only", false));
+        segmentReplicationStatsRequest.indicesOptions(IndicesOptions.fromRequest(request, segmentReplicationStatsRequest.indicesOptions()));
+
+        return channel -> client.admin()
+            .indices()
+            .segmentReplicationStats(segmentReplicationStatsRequest, new RestResponseListener<>(channel) {
+                @Override
+                public RestResponse buildResponse(final SegmentReplicationStatsResponse response) throws Exception {
+                    return RestTable.buildResponse(buildSegmentReplicationTable(request, response), channel);
+                }
+            });
+    }
+
+    @Override
+    protected Table getTableWithHeader(RestRequest request) {
+
+        boolean detailed = false;
+        if (request != null) {
+            detailed = Boolean.parseBoolean(request.param("detailed"));
+        }
+
+        Table t = new Table();
+        t.startHeaders()
+            .addCell("shardId", "alias:s;desc: shard Id")
+            .addCell("target_node", "alias:tnode;desc:target node name")
+            .addCell("target_host", "alias:thost;desc:target host")
+            .addCell("checkpoints_behind", "alias:cpb;desc:checkpoints behind primary")
+            .addCell("bytes_behind", "alias:bb;desc:bytes behind primary")
+            .addCell("current_lag", "alias:clag;desc:ongoing time elapsed waiting for replica to catch up to primary")
+            .addCell("last_completed_lag", "alias:lcl;desc:time taken for replica to catch up to latest primary refresh")
+            .addCell("rejected_requests", "alias:rr;desc:count of rejected requests for the replication group");
+        if (detailed) {
+            t.addCell("stage", "alias:st;desc:segment replication event stage")
+                .addCell("time", "alias:t,ti;desc:current replication event time")
+                .addCell("files_fetched", "alias:ff;desc:files fetched")
+                .addCell("files_percent", "alias:fp;desc:percent of files fetched")
+                .addCell("bytes_fetched", "alias:bf;desc:bytes fetched")
+                .addCell("bytes_percent", "alias:bp;desc:percent of bytes fetched")
+                .addCell("start_time", "alias:start;desc:segment replication start time")
+                .addCell("stop_time", "alias:stop;desc:segment replication stop time")
+                .addCell("files", "alias:f;desc:number of files to fetch")
+                .addCell("files_total", "alias:tf;desc:total number of files")
+                .addCell("bytes", "alias:b;desc:number of bytes to fetch")
+                .addCell("bytes_total", "alias:tb;desc:total number of bytes")
+                .addCell("replicating_stage_time_taken", "alias:rstt;desc:time taken in replicating stage")
+                .addCell("get_checkpoint_info_stage_time_taken", "alias:gcistt;desc:time taken in get checkpoint info stage")
+                .addCell("file_diff_stage_time_taken", "alias:fdstt;desc:time taken in file diff stage")
+                .addCell("get_files_stage_time_taken", "alias:gfstt;desc:time taken in get files stage")
+                .addCell("finalize_replication_stage_time_taken", "alias:frstt;desc:time taken in finalize replication stage");
+        }
+        t.endHeaders();
+        return t;
+    }
+
+    /**
+     * buildSegmentReplicationTable will build a table of SegmentReplication information suitable
+     * for displaying at the command line.
+     *
+     * @param request  A Rest request
+     * @param response A SegmentReplication status response
+     * @return A table containing index, shardId, node, target size, fetched size and percentage for each fetching replica
+     */
+    public Table buildSegmentReplicationTable(RestRequest request, SegmentReplicationStatsResponse response) {
+        boolean detailed = false;
+        if (request != null) {
+            detailed = Boolean.parseBoolean(request.param("detailed"));
+        }
+        Table t = getTableWithHeader(request);
+
+        for (Map.Entry<String, List<SegmentReplicationPerGroupStats>> entry : response.getReplicationStats().entrySet()) {
+            final List<SegmentReplicationPerGroupStats> replicationPerGroupStats = entry.getValue();
+
+            if (replicationPerGroupStats.isEmpty()) {
+                continue;
+            }
+
+            // Sort ascending by shard id for readability
+            CollectionUtil.introSort(replicationPerGroupStats, (o1, o2) -> {
+                int id1 = o1.getShardId().id();
+                int id2 = o2.getShardId().id();
+                return Integer.compare(id1, id2);
+            });
+
+            for (SegmentReplicationPerGroupStats perGroupStats : replicationPerGroupStats) {
+
+                final Set<SegmentReplicationShardStats> replicaShardStats = perGroupStats.getReplicaStats();
+
+                for (SegmentReplicationShardStats shardStats : replicaShardStats) {
+                    final SegmentReplicationState state = shardStats.getCurrentReplicationState();
+                    if (state == null) {
+                        continue;
+                    }
+
+                    t.startRow();
+                    t.addCell(perGroupStats.getShardId());
+                    // these nulls should never happen, here for safety.
+                    t.addCell(state.getTargetNode().getName());
+                    t.addCell(state.getTargetNode().getHostName());
+                    t.addCell(shardStats.getCheckpointsBehindCount());
+                    t.addCell(new ByteSizeValue(shardStats.getBytesBehindCount()));
+                    t.addCell(new TimeValue(shardStats.getCurrentReplicationLagMillis()));
+                    t.addCell(new TimeValue(shardStats.getLastCompletedReplicationTimeMillis()));
+                    t.addCell(perGroupStats.getRejectedRequestCount());
+                    if (detailed) {
+                        t.addCell(state.getStage().toString().toLowerCase(Locale.ROOT));
+                        t.addCell(new TimeValue(state.getTimer().time()));
+                        t.addCell(state.getIndex().recoveredFileCount());
+                        t.addCell(String.format(Locale.ROOT, "%1.1f%%", state.getIndex().recoveredFilesPercent()));
+                        t.addCell(state.getIndex().recoveredBytes());
+                        t.addCell(String.format(Locale.ROOT, "%1.1f%%", state.getIndex().recoveredBytesPercent()));
+                        t.addCell(XContentOpenSearchExtension.DEFAULT_DATE_PRINTER.print(state.getTimer().startTime()));
+                        t.addCell(XContentOpenSearchExtension.DEFAULT_DATE_PRINTER.print(state.getTimer().stopTime()));
+                        t.addCell(state.getIndex().totalRecoverFiles());
+                        t.addCell(state.getIndex().totalFileCount());
+                        t.addCell(new ByteSizeValue(state.getIndex().totalRecoverBytes()));
+                        t.addCell(new ByteSizeValue(state.getIndex().totalBytes()));
+                        t.addCell(state.getReplicatingStageTime());
+                        t.addCell(state.getGetCheckpointInfoStageTime());
+                        t.addCell(state.getFileDiffStageTime());
+                        t.addCell(state.getGetFileStageTime());
+                        t.addCell(state.getFinalizeReplicationStageTime());
+                    }
+                    t.endRow();
+                }
+            }
+        }
+
+        return t;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestClusterManagerAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestClusterManagerAction.java
new file mode 100644
index 0000000000000..ac57ba16abcf8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestClusterManagerAction.java
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.rest.action.cat;
+
+import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestResponse;
+import org.opensearch.rest.action.RestResponseListener;
+
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * _cat API action to list cluster_manager information
+ *
+ * @opensearch.api
+ */
+public class RestClusterManagerAction extends AbstractCatAction {
+
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterManagerAction.class);
+
+    @Override
+    public List<ReplacedRoute> replacedRoutes() {
+        // The deprecated path will be removed in a future major version.
+        return singletonList(new ReplacedRoute(GET, "/_cat/cluster_manager", "/_cat/master"));
+    }
+
+    @Override
+    public String getName() {
+        return "cat_cluster_manager_action";
+    }
+
+    @Override
+    protected void documentation(StringBuilder sb) {
+        sb.append("/_cat/cluster_manager\n");
+    }
+
+    @Override
+    public RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
+        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
+        clusterStateRequest.clear().nodes(true);
+        clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
+
+        return channel -> client.admin().cluster().state(clusterStateRequest, new RestResponseListener<ClusterStateResponse>(channel) {
+            @Override
+            public RestResponse buildResponse(final ClusterStateResponse clusterStateResponse) throws Exception {
+                return RestTable.buildResponse(buildTable(request, clusterStateResponse), channel);
+            }
+        });
+    }
+
+    @Override
+    public boolean canTripCircuitBreaker() {
+        return false;
+    }
+
+    @Override
+    protected Table getTableWithHeader(final RestRequest request) {
+        Table table = new Table();
+        table.startHeaders()
+            .addCell("id", "desc:node id")
+            .addCell("host", "alias:h;desc:host name")
+            .addCell("ip", "desc:ip address ")
+            .addCell("node", "alias:n;desc:node name")
+            .endHeaders();
+        return table;
+    }
+
+    private Table buildTable(RestRequest request, ClusterStateResponse state) {
+        Table table = getTableWithHeader(request);
+        DiscoveryNodes nodes = state.getState().nodes();
+
+        table.startRow();
+        DiscoveryNode clusterManager = nodes.get(nodes.getClusterManagerNodeId());
+        if (clusterManager == null) {
+            table.addCell("-");
+            table.addCell("-");
+            table.addCell("-");
+            table.addCell("-");
+        } else {
+            table.addCell(clusterManager.getId());
+            table.addCell(clusterManager.getHostName());
+            table.addCell(clusterManager.getHostAddress());
+            table.addCell(clusterManager.getName());
+        }
+        table.endRow();
+
+        return table;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestCountAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestCountAction.java
index 033c9a278cabc..9c054ffe1bcc7 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestCountAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestCountAction.java
@@ -37,8 +37,8 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -53,6 +53,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to count documents in an index
+ *
+ * @opensearch.api
+ */
 public class RestCountAction extends AbstractCatAction {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestFielddataAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestFielddataAction.java
index 02de5f7301425..04bbdeeadc4c4 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestFielddataAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestFielddataAction.java
@@ -32,13 +32,12 @@
 
 package org.opensearch.rest.action.cat;
 
-import com.carrotsearch.hppc.cursors.ObjectLongCursor;
 import org.opensearch.action.admin.cluster.node.stats.NodeStats;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.Table;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestResponseListener;
@@ -51,6 +50,8 @@
 
 /**
  * Cat API class to display information about the size of fielddata fields per node
+ *
+ * @opensearch.api
  */
 public class RestFielddataAction extends AbstractCatAction {
 
@@ -105,14 +106,14 @@ private Table buildTable(final RestRequest request, final NodesStatsResponse nod
 
         for (NodeStats nodeStats : nodeStatses.getNodes()) {
             if (nodeStats.getIndices().getFieldData().getFields() != null) {
-                for (ObjectLongCursor<String> cursor : nodeStats.getIndices().getFieldData().getFields()) {
+                for (var cursor : nodeStats.getIndices().getFieldData().getFields()) {
                     table.startRow();
                     table.addCell(nodeStats.getNode().getId());
                     table.addCell(nodeStats.getNode().getHostName());
                     table.addCell(nodeStats.getNode().getHostAddress());
                     table.addCell(nodeStats.getNode().getName());
-                    table.addCell(cursor.key);
-                    table.addCell(new ByteSizeValue(cursor.value));
+                    table.addCell(cursor.getKey());
+                    table.addCell(new ByteSizeValue(cursor.getValue()));
                     table.endRow();
                 }
             }
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestHealthAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestHealthAction.java
index c05b0b9c77129..b4d336f4c10c0 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestHealthAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestHealthAction.java
@@ -46,6 +46,11 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get cluster health
+ *
+ * @opensearch.api
+ */
 public class RestHealthAction extends AbstractCatAction {
 
     @Override
@@ -114,7 +119,7 @@ private Table buildTable(final ClusterHealthResponse health, final RestRequest r
         t.addCell(health.getStatus().name().toLowerCase(Locale.ROOT));
         t.addCell(health.getNumberOfNodes());
         t.addCell(health.getNumberOfDataNodes());
-        t.addCell(health.hasDiscoveredMaster());
+        t.addCell(health.hasDiscoveredClusterManager());
         t.addCell(health.getActiveShards());
         t.addCell(health.getActivePrimaryShards());
         t.addCell(health.getRelocatingShards());
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestIndicesAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestIndicesAction.java
index 2c0eef6a8fdb8..dea4f02aef5bd 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestIndicesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestIndicesAction.java
@@ -32,8 +32,7 @@
 
 package org.opensearch.rest.action.cat;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
@@ -50,11 +49,14 @@
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.health.ClusterIndexHealth;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -70,15 +72,21 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.Spliterators;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
-import static org.opensearch.action.support.master.MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT;
+import static org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to list indices
+ *
+ * @opensearch.api
+ */
 public class RestIndicesAction extends AbstractCatAction {
 
     private static final DateFormatter STRICT_DATE_TIME_FORMATTER = DateFormatter.forPattern("strict_date_time");
@@ -109,7 +117,15 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final String[] indices = Strings.splitStringByCommaToArray(request.param("index"));
         final IndicesOptions indicesOptions = IndicesOptions.fromRequest(request, IndicesOptions.strictExpand());
         final boolean local = request.paramAsBoolean("local", false);
-        final TimeValue masterNodeTimeout = request.paramAsTime("master_timeout", DEFAULT_MASTER_NODE_TIMEOUT);
+        TimeValue clusterManagerTimeout = request.paramAsTime("cluster_manager_timeout", DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT);
+        // Remove the if condition and statements inside after removing MASTER_ROLE.
+        if (request.hasParam("master_timeout")) {
+            if (request.hasParam("cluster_manager_timeout")) {
+                throw new OpenSearchParseException(DUPLICATE_PARAMETER_ERROR_MESSAGE);
+            }
+            clusterManagerTimeout = request.paramAsTime("master_timeout", DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT);
+        }
+        final TimeValue clusterManagerNodeTimeout = clusterManagerTimeout;
         final boolean includeUnloadedSegments = request.paramAsBoolean("include_unloaded_segments", false);
 
         return channel -> {
@@ -120,56 +136,66 @@ public RestResponse buildResponse(final Table table) throws Exception {
                 }
             });
 
-            sendGetSettingsRequest(indices, indicesOptions, local, masterNodeTimeout, client, new ActionListener<GetSettingsResponse>() {
-                @Override
-                public void onResponse(final GetSettingsResponse getSettingsResponse) {
-                    final GroupedActionListener<ActionResponse> groupedListener = createGroupedListener(request, 4, listener);
-                    groupedListener.onResponse(getSettingsResponse);
-
-                    // The list of indices that will be returned is determined by the indices returned from the Get Settings call.
-                    // All the other requests just provide additional detail, and wildcards may be resolved differently depending on the
-                    // type of request in the presence of security plugins (looking at you, ClusterHealthRequest), so
-                    // force the IndicesOptions for all the sub-requests to be as inclusive as possible.
-                    final IndicesOptions subRequestIndicesOptions = IndicesOptions.lenientExpandHidden();
-
-                    // Indices that were successfully resolved during the get settings request might be deleted when the subsequent cluster
-                    // state, cluster health and indices stats requests execute. We have to distinguish two cases:
-                    // 1) the deleted index was explicitly passed as parameter to the /_cat/indices request. In this case we want the
-                    // subsequent requests to fail.
-                    // 2) the deleted index was resolved as part of a wildcard or _all. In this case, we want the subsequent requests not to
-                    // fail on the deleted index (as we want to ignore wildcards that cannot be resolved).
-                    // This behavior can be ensured by letting the cluster state, cluster health and indices stats requests re-resolve the
-                    // index names with the same indices options that we used for the initial cluster state request (strictExpand).
-                    sendIndicesStatsRequest(
-                        indices,
-                        subRequestIndicesOptions,
-                        includeUnloadedSegments,
-                        client,
-                        ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
-                    );
-                    sendClusterStateRequest(
-                        indices,
-                        subRequestIndicesOptions,
-                        local,
-                        masterNodeTimeout,
-                        client,
-                        ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
-                    );
-                    sendClusterHealthRequest(
-                        indices,
-                        subRequestIndicesOptions,
-                        local,
-                        masterNodeTimeout,
-                        client,
-                        ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
-                    );
-                }
-
-                @Override
-                public void onFailure(final Exception e) {
-                    listener.onFailure(e);
+            sendGetSettingsRequest(
+                indices,
+                indicesOptions,
+                local,
+                clusterManagerNodeTimeout,
+                client,
+                new ActionListener<GetSettingsResponse>() {
+                    @Override
+                    public void onResponse(final GetSettingsResponse getSettingsResponse) {
+                        final GroupedActionListener<ActionResponse> groupedListener = createGroupedListener(request, 4, listener);
+                        groupedListener.onResponse(getSettingsResponse);
+
+                        // The list of indices that will be returned is determined by the indices returned from the Get Settings call.
+                        // All the other requests just provide additional detail, and wildcards may be resolved differently depending on the
+                        // type of request in the presence of security plugins (looking at you, ClusterHealthRequest), so
+                        // force the IndicesOptions for all the sub-requests to be as inclusive as possible.
+                        final IndicesOptions subRequestIndicesOptions = IndicesOptions.lenientExpandHidden();
+
+                        // Indices that were successfully resolved during the get settings request might be deleted when the subsequent
+                        // cluster
+                        // state, cluster health and indices stats requests execute. We have to distinguish two cases:
+                        // 1) the deleted index was explicitly passed as parameter to the /_cat/indices request. In this case we want the
+                        // subsequent requests to fail.
+                        // 2) the deleted index was resolved as part of a wildcard or _all. In this case, we want the subsequent requests
+                        // not to
+                        // fail on the deleted index (as we want to ignore wildcards that cannot be resolved).
+                        // This behavior can be ensured by letting the cluster state, cluster health and indices stats requests re-resolve
+                        // the
+                        // index names with the same indices options that we used for the initial cluster state request (strictExpand).
+                        sendIndicesStatsRequest(
+                            indices,
+                            subRequestIndicesOptions,
+                            includeUnloadedSegments,
+                            client,
+                            ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
+                        );
+                        sendClusterStateRequest(
+                            indices,
+                            subRequestIndicesOptions,
+                            local,
+                            clusterManagerNodeTimeout,
+                            client,
+                            ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
+                        );
+                        sendClusterHealthRequest(
+                            indices,
+                            subRequestIndicesOptions,
+                            local,
+                            clusterManagerNodeTimeout,
+                            client,
+                            ActionListener.wrap(groupedListener::onResponse, groupedListener::onFailure)
+                        );
+                    }
+
+                    @Override
+                    public void onFailure(final Exception e) {
+                        listener.onFailure(e);
+                    }
                 }
-            });
+            );
         };
     }
 
@@ -185,7 +211,7 @@ private void sendGetSettingsRequest(
         final String[] indices,
         final IndicesOptions indicesOptions,
         final boolean local,
-        final TimeValue masterNodeTimeout,
+        final TimeValue clusterManagerNodeTimeout,
         final NodeClient client,
         final ActionListener<GetSettingsResponse> listener
     ) {
@@ -193,7 +219,7 @@ private void sendGetSettingsRequest(
         request.indices(indices);
         request.indicesOptions(indicesOptions);
         request.local(local);
-        request.masterNodeTimeout(masterNodeTimeout);
+        request.clusterManagerNodeTimeout(clusterManagerNodeTimeout);
         request.names(IndexSettings.INDEX_SEARCH_THROTTLED.getKey());
 
         client.admin().indices().getSettings(request, listener);
@@ -203,7 +229,7 @@ private void sendClusterStateRequest(
         final String[] indices,
         final IndicesOptions indicesOptions,
         final boolean local,
-        final TimeValue masterNodeTimeout,
+        final TimeValue clusterManagerNodeTimeout,
         final NodeClient client,
         final ActionListener<ClusterStateResponse> listener
     ) {
@@ -212,7 +238,7 @@ private void sendClusterStateRequest(
         request.indices(indices);
         request.indicesOptions(indicesOptions);
         request.local(local);
-        request.masterNodeTimeout(masterNodeTimeout);
+        request.clusterManagerNodeTimeout(clusterManagerNodeTimeout);
 
         client.admin().cluster().state(request, listener);
     }
@@ -221,7 +247,7 @@ private void sendClusterHealthRequest(
         final String[] indices,
         final IndicesOptions indicesOptions,
         final boolean local,
-        final TimeValue masterNodeTimeout,
+        final TimeValue clusterManagerNodeTimeout,
         final NodeClient client,
         final ActionListener<ClusterHealthResponse> listener
     ) {
@@ -230,7 +256,7 @@ private void sendClusterHealthRequest(
         request.indices(indices);
         request.indicesOptions(indicesOptions);
         request.local(local);
-        request.masterNodeTimeout(masterNodeTimeout);
+        request.clusterManagerNodeTimeout(clusterManagerNodeTimeout);
 
         client.admin().cluster().health(request, listener);
     }
@@ -262,8 +288,10 @@ private GroupedActionListener<ActionResponse> createGroupedListener(
             public void onResponse(final Collection<ActionResponse> responses) {
                 try {
                     GetSettingsResponse settingsResponse = extractResponse(responses, GetSettingsResponse.class);
-                    Map<String, Settings> indicesSettings = StreamSupport.stream(settingsResponse.getIndexToSettings().spliterator(), false)
-                        .collect(Collectors.toMap(cursor -> cursor.key, cursor -> cursor.value));
+                    Map<String, Settings> indicesSettings = StreamSupport.stream(
+                        Spliterators.spliterator(settingsResponse.getIndexToSettings().entrySet(), 0),
+                        false
+                    ).collect(Collectors.toMap(cursor -> cursor.getKey(), cursor -> cursor.getValue()));
 
                     ClusterStateResponse stateResponse = extractResponse(responses, ClusterStateResponse.class);
                     Map<String, IndexMetadata> indicesStates = StreamSupport.stream(
@@ -547,6 +575,31 @@ protected Table getTableWithHeader(final RestRequest request) {
             "sibling:pri;alias:sqto,searchQueryTotal;default:false;text-align:right;desc:total query phase ops"
         );
         table.addCell("pri.search.query_total", "default:false;text-align:right;desc:total query phase ops");
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            table.addCell(
+                "search.concurrent_query_current",
+                "sibling:pri;alias:scqc,searchConcurrentQueryCurrent;default:false;text-align:right;desc:current concurrent query phase ops"
+            );
+            table.addCell("pri.search.concurrent_query_current", "default:false;text-align:right;desc:current concurrent query phase ops");
+
+            table.addCell(
+                "search.concurrent_query_time",
+                "sibling:pri;alias:scqti,searchConcurrentQueryTime;default:false;text-align:right;desc:time spent in concurrent query phase"
+            );
+            table.addCell("pri.search.concurrent_query_time", "default:false;text-align:right;desc:time spent in concurrent query phase");
+
+            table.addCell(
+                "search.concurrent_query_total",
+                "sibling:pri;alias:scqto,searchConcurrentQueryTotal;default:false;text-align:right;desc:total query phase ops"
+            );
+            table.addCell("pri.search.concurrent_query_total", "default:false;text-align:right;desc:total query phase ops");
+
+            table.addCell(
+                "search.concurrent_avg_slice_count",
+                "sibling:pri;alias:casc,searchConcurrentAvgSliceCount;default:false;text-align:right;desc:average query concurrency"
+            );
+            table.addCell("pri.search.concurrent_avg_slice_count", "default:false;text-align:right;desc:average query concurrency");
+        }
 
         table.addCell(
             "search.scroll_current",
@@ -566,6 +619,24 @@ protected Table getTableWithHeader(final RestRequest request) {
         );
         table.addCell("pri.search.scroll_total", "default:false;text-align:right;desc:completed scroll contexts");
 
+        table.addCell(
+            "search.point_in_time_current",
+            "sibling:pri;alias:scc,searchPointInTimeCurrent;default:false;text-align:right;desc:open point in time contexts"
+        );
+        table.addCell("pri.search.point_in_time_current", "default:false;text-align:right;desc:open point in time contexts");
+
+        table.addCell(
+            "search.point_in_time_time",
+            "sibling:pri;alias:scti,searchPointInTimeTime;default:false;text-align:right;desc:time point in time contexts held open"
+        );
+        table.addCell("pri.search.point_in_time_time", "default:false;text-align:right;desc:time point in time contexts held open");
+
+        table.addCell(
+            "search.point_in_time_total",
+            "sibling:pri;alias:scto,searchPointInTimeTotal;default:false;text-align:right;desc:completed point in time contexts"
+        );
+        table.addCell("pri.search.point_in_time_total", "default:false;text-align:right;desc:completed point in time contexts");
+
         table.addCell("segments.count", "sibling:pri;alias:sc,segmentsCount;default:false;text-align:right;desc:number of segments");
         table.addCell("pri.segments.count", "default:false;text-align:right;desc:number of segments");
 
@@ -838,6 +909,20 @@ Table buildTable(
             table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getQueryCount());
             table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getQueryCount());
 
+            if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+                table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getConcurrentQueryCurrent());
+                table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getConcurrentQueryCurrent());
+
+                table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getConcurrentQueryTime());
+                table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getConcurrentQueryTime());
+
+                table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getConcurrentQueryCount());
+                table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getConcurrentQueryCount());
+
+                table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getConcurrentAvgSliceCount());
+                table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getConcurrentAvgSliceCount());
+            }
+
             table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getScrollCurrent());
             table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getScrollCurrent());
 
@@ -847,6 +932,15 @@ Table buildTable(
             table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getScrollCount());
             table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getScrollCount());
 
+            table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getPitCurrent());
+            table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getPitCurrent());
+
+            table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getPitTime());
+            table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getPitTime());
+
+            table.addCell(totalStats.getSearch() == null ? null : totalStats.getSearch().getTotal().getPitCount());
+            table.addCell(primaryStats.getSearch() == null ? null : primaryStats.getSearch().getTotal().getPitCount());
+
             table.addCell(totalStats.getSegments() == null ? null : totalStats.getSegments().getCount());
             table.addCell(primaryStats.getSegments() == null ? null : primaryStats.getSegments().getCount());
 
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestMasterAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestMasterAction.java
index 1219b419122c6..7a3e2c7b92ef2 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestMasterAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestMasterAction.java
@@ -6,116 +6,15 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.rest.action.cat;
 
-import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
-import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
-import org.opensearch.client.node.NodeClient;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Table;
-import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.action.RestResponseListener;
-
-import java.util.List;
-
-import static java.util.Collections.singletonList;
-import static org.opensearch.rest.RestRequest.Method.GET;
-
-public class RestMasterAction extends AbstractCatAction {
-
-    @Override
-    public List<ReplacedRoute> replacedRoutes() {
-        // The deprecated path will be removed in a future major version.
-        return singletonList(new ReplacedRoute(GET, "/_cat/cluster_manager", "/_cat/master"));
-    }
-
-    @Override
-    public String getName() {
-        return "cat_cluster_manager_action";
-    }
-
-    @Override
-    protected void documentation(StringBuilder sb) {
-        sb.append("/_cat/cluster_manager\n");
-    }
-
-    @Override
-    public RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
-        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
-        clusterStateRequest.clear().nodes(true);
-        clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
-
-        return channel -> client.admin().cluster().state(clusterStateRequest, new RestResponseListener<ClusterStateResponse>(channel) {
-            @Override
-            public RestResponse buildResponse(final ClusterStateResponse clusterStateResponse) throws Exception {
-                return RestTable.buildResponse(buildTable(request, clusterStateResponse), channel);
-            }
-        });
-    }
-
-    @Override
-    public boolean canTripCircuitBreaker() {
-        return false;
-    }
-
-    @Override
-    protected Table getTableWithHeader(final RestRequest request) {
-        Table table = new Table();
-        table.startHeaders()
-            .addCell("id", "desc:node id")
-            .addCell("host", "alias:h;desc:host name")
-            .addCell("ip", "desc:ip address ")
-            .addCell("node", "alias:n;desc:node name")
-            .endHeaders();
-        return table;
-    }
-
-    private Table buildTable(RestRequest request, ClusterStateResponse state) {
-        Table table = getTableWithHeader(request);
-        DiscoveryNodes nodes = state.getState().nodes();
-
-        table.startRow();
-        DiscoveryNode master = nodes.get(nodes.getMasterNodeId());
-        if (master == null) {
-            table.addCell("-");
-            table.addCell("-");
-            table.addCell("-");
-            table.addCell("-");
-        } else {
-            table.addCell(master.getId());
-            table.addCell(master.getHostName());
-            table.addCell(master.getHostAddress());
-            table.addCell(master.getName());
-        }
-        table.endRow();
+/**
+ * _cat API action to list cluster_manager information
+ *
+ * @opensearch.api
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link RestClusterManagerAction}
+ */
+@Deprecated
+public class RestMasterAction extends RestClusterManagerAction {
 
-        return table;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestNodeAttrsAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestNodeAttrsAction.java
index d6fc27a2713db..eca2ca1be166c 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestNodeAttrsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestNodeAttrsAction.java
@@ -40,8 +40,9 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.monitor.process.ProcessInfo;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -54,8 +55,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get node attributes
+ *
+ * @opensearch.api
+ */
 public class RestNodeAttrsAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestNodeAttrsAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_cat/nodeattrs"));
@@ -76,7 +84,10 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear().nodes(true);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
             @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestNodesAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestNodesAction.java
index abc4b48b01cff..bf8b27f378311 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestNodesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestNodesAction.java
@@ -44,12 +44,13 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.network.NetworkAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.cache.request.RequestCacheStats;
@@ -82,12 +83,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get node information
+ *
+ * @opensearch.api
+ */
 public class RestNodesAction extends AbstractCatAction {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestNodesAction.class);
     static final String LOCAL_DEPRECATED_MESSAGE = "Deprecated parameter [local] used. This parameter does not cause this API to act "
         + "locally, and should not be used. It will be unsupported in version 8.0.";
-    static final String MASTER_TIMEOUT_DEPRECATED_MESSAGE =
-        "Deprecated parameter [master_timeout] used. To promote inclusive language, please use [cluster_manager_timeout] instead. It will be unsupported in a future major version.";
 
     @Override
     public List<Route> routes() {
@@ -112,7 +116,9 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
             deprecationLogger.deprecate("cat_nodes_local_parameter", LOCAL_DEPRECATED_MESSAGE);
         }
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("cluster_manager_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
         parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
         final boolean fullId = request.paramAsBoolean("full_id", false);
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
@@ -192,10 +198,12 @@ protected Table getTableWithHeader(final RestRequest request) {
         table.addCell("load_5m", "alias:l;text-align:right;desc:5m load avg");
         table.addCell("load_15m", "alias:l;text-align:right;desc:15m load avg");
         table.addCell("uptime", "default:false;alias:u;text-align:right;desc:node uptime");
+        // TODO: Deprecate "node.role", use "node.roles" which shows full node role names
         table.addCell(
             "node.role",
             "alias:r,role,nodeRole;desc:m:master eligible node, d:data node, i:ingest node, -:coordinating node only"
         );
+        table.addCell("node.roles", "alias:rs,all roles;desc: -:coordinating node only");
         // TODO: Remove the header alias 'master', after removing MASTER_ROLE. It's added for compatibility when using parameter 'h=master'.
         table.addCell("cluster_manager", "alias:cm,m,master;desc:*:current cluster manager");
         table.addCell("name", "alias:n;desc:node name");
@@ -296,6 +304,24 @@ protected Table getTableWithHeader(final RestRequest request) {
         table.addCell("search.query_current", "alias:sqc,searchQueryCurrent;default:false;text-align:right;desc:current query phase ops");
         table.addCell("search.query_time", "alias:sqti,searchQueryTime;default:false;text-align:right;desc:time spent in query phase");
         table.addCell("search.query_total", "alias:sqto,searchQueryTotal;default:false;text-align:right;desc:total query phase ops");
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            table.addCell(
+                "search.concurrent_query_current",
+                "alias:scqc,searchConcurrentQueryCurrent;default:false;text-align:right;desc:current concurrent query phase ops"
+            );
+            table.addCell(
+                "search.concurrent_query_time",
+                "alias:scqti,searchConcurrentQueryTime;default:false;text-align:right;desc:time spent in concurrent query phase"
+            );
+            table.addCell(
+                "search.concurrent_query_total",
+                "alias:scqto,searchConcurrentQueryTotal;default:false;text-align:right;desc:total concurrent query phase ops"
+            );
+            table.addCell(
+                "search.concurrent_avg_slice_count",
+                "alias:casc,searchConcurrentAvgSliceCount;default:false;text-align:right;desc:average query concurrency"
+            );
+        }
         table.addCell("search.scroll_current", "alias:scc,searchScrollCurrent;default:false;text-align:right;desc:open scroll contexts");
         table.addCell(
             "search.scroll_time",
@@ -303,6 +329,19 @@ protected Table getTableWithHeader(final RestRequest request) {
         );
         table.addCell("search.scroll_total", "alias:scto,searchScrollTotal;default:false;text-align:right;desc:completed scroll contexts");
 
+        table.addCell(
+            "search.point_in_time_current",
+            "alias:scc,searchPointInTimeCurrent;default:false;text-align:right;desc:open point in time contexts"
+        );
+        table.addCell(
+            "search.point_in_time_time",
+            "alias:scti,searchPointInTimeTime;default:false;text-align:right;desc:time point in time contexts held open"
+        );
+        table.addCell(
+            "search.point_in_time_total",
+            "alias:scto,searchPointInTimeTotal;default:false;text-align:right;desc:completed point in time contexts"
+        );
+
         table.addCell("segments.count", "alias:sc,segmentsCount;default:false;text-align:right;desc:number of segments");
         table.addCell("segments.memory", "alias:sm,segmentsMemory;default:false;text-align:right;desc:memory used by segments");
         table.addCell(
@@ -336,7 +375,7 @@ Table buildTable(
     ) {
 
         DiscoveryNodes nodes = state.getState().nodes();
-        String masterId = nodes.getMasterNodeId();
+        String clusterManagerId = nodes.getClusterManagerNodeId();
         Table table = getTableWithHeader(req);
 
         for (DiscoveryNode node : nodes) {
@@ -420,13 +459,23 @@ Table buildTable(
             table.addCell(jvmStats == null ? null : jvmStats.getUptime());
 
             final String roles;
+            final String allRoles;
             if (node.getRoles().isEmpty()) {
                 roles = "-";
+                allRoles = "-";
             } else {
-                roles = node.getRoles().stream().map(DiscoveryNodeRole::roleNameAbbreviation).sorted().collect(Collectors.joining());
+                List<DiscoveryNodeRole> knownNodeRoles = node.getRoles()
+                    .stream()
+                    .filter(DiscoveryNodeRole::isKnownRole)
+                    .collect(Collectors.toList());
+                roles = knownNodeRoles.size() > 0
+                    ? knownNodeRoles.stream().map(DiscoveryNodeRole::roleNameAbbreviation).sorted().collect(Collectors.joining())
+                    : "-";
+                allRoles = node.getRoles().stream().map(DiscoveryNodeRole::roleName).sorted().collect(Collectors.joining(","));
             }
             table.addCell(roles);
-            table.addCell(masterId == null ? "x" : masterId.equals(node.getId()) ? "*" : "-");
+            table.addCell(allRoles);
+            table.addCell(clusterManagerId == null ? "x" : clusterManagerId.equals(node.getId()) ? "*" : "-");
             table.addCell(node.getName());
 
             CompletionStats completionStats = indicesStats == null ? null : stats.getIndices().getCompletion();
@@ -499,9 +548,18 @@ Table buildTable(
             table.addCell(searchStats == null ? null : searchStats.getTotal().getQueryCurrent());
             table.addCell(searchStats == null ? null : searchStats.getTotal().getQueryTime());
             table.addCell(searchStats == null ? null : searchStats.getTotal().getQueryCount());
+            if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+                table.addCell(searchStats == null ? null : searchStats.getTotal().getConcurrentQueryCurrent());
+                table.addCell(searchStats == null ? null : searchStats.getTotal().getConcurrentQueryTime());
+                table.addCell(searchStats == null ? null : searchStats.getTotal().getConcurrentQueryCount());
+                table.addCell(searchStats == null ? null : searchStats.getTotal().getConcurrentAvgSliceCount());
+            }
             table.addCell(searchStats == null ? null : searchStats.getTotal().getScrollCurrent());
             table.addCell(searchStats == null ? null : searchStats.getTotal().getScrollTime());
             table.addCell(searchStats == null ? null : searchStats.getTotal().getScrollCount());
+            table.addCell(searchStats == null ? null : searchStats.getTotal().getPitCurrent());
+            table.addCell(searchStats == null ? null : searchStats.getTotal().getPitTime());
+            table.addCell(searchStats == null ? null : searchStats.getTotal().getPitCount());
 
             SegmentsStats segmentsStats = indicesStats == null ? null : indicesStats.getSegments();
             table.addCell(segmentsStats == null ? null : segmentsStats.getCount());
@@ -529,20 +587,4 @@ Table buildTable(
     private short calculatePercentage(long used, long max) {
         return max <= 0 ? 0 : (short) ((100d * used) / max);
     }
-
-    /**
-     * Parse the deprecated request parameter 'master_timeout', and add deprecated log if the parameter is used.
-     * It also validates whether the value of 'master_timeout' is the same with 'cluster_manager_timeout'.
-     * Remove the method along with MASTER_ROLE.
-     * @deprecated As of 2.0, because promoting inclusive language.
-     */
-    @Deprecated
-    private void parseDeprecatedMasterTimeoutParameter(ClusterStateRequest clusterStateRequest, RestRequest request) {
-        final String deprecatedTimeoutParam = "master_timeout";
-        if (request.hasParam(deprecatedTimeoutParam)) {
-            deprecationLogger.deprecate("cat_nodes_master_timeout_parameter", MASTER_TIMEOUT_DEPRECATED_MESSAGE);
-            request.validateParamValuesAreEqual(deprecatedTimeoutParam, "cluster_manager_timeout");
-            clusterStateRequest.masterNodeTimeout(request.paramAsTime(deprecatedTimeoutParam, clusterStateRequest.masterNodeTimeout()));
-        }
-    }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestPendingClusterTasksAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestPendingClusterTasksAction.java
index dbc1b21fcf0ab..d30b9bccc7b49 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestPendingClusterTasksAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestPendingClusterTasksAction.java
@@ -37,6 +37,7 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.service.PendingClusterTask;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestResponseListener;
@@ -46,8 +47,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get pending cluster tasks
+ *
+ * @opensearch.api
+ */
 public class RestPendingClusterTasksAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPendingClusterTasksAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_cat/pending_tasks"));
@@ -66,7 +74,10 @@ protected void documentation(StringBuilder sb) {
     @Override
     public RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
         PendingClusterTasksRequest pendingClusterTasksRequest = new PendingClusterTasksRequest();
-        pendingClusterTasksRequest.masterNodeTimeout(request.paramAsTime("master_timeout", pendingClusterTasksRequest.masterNodeTimeout()));
+        pendingClusterTasksRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", pendingClusterTasksRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(pendingClusterTasksRequest, request);
         pendingClusterTasksRequest.local(request.paramAsBoolean("local", pendingClusterTasksRequest.local()));
         return channel -> client.admin()
             .cluster()
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestPitSegmentsAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestPitSegmentsAction.java
new file mode 100644
index 0000000000000..5fc6c961b4637
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestPitSegmentsAction.java
@@ -0,0 +1,155 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.cat;
+
+import org.opensearch.action.admin.indices.segments.IndexSegments;
+import org.opensearch.action.admin.indices.segments.IndexShardSegments;
+import org.opensearch.action.admin.indices.segments.IndicesSegmentResponse;
+import org.opensearch.action.admin.indices.segments.PitSegmentsAction;
+import org.opensearch.action.admin.indices.segments.PitSegmentsRequest;
+import org.opensearch.action.admin.indices.segments.ShardSegments;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.Table;
+import org.opensearch.index.engine.Segment;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestResponse;
+import org.opensearch.rest.action.RestResponseListener;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * Rest action for pit segments
+ */
+public class RestPitSegmentsAction extends AbstractCatAction {
+    private final Supplier<DiscoveryNodes> nodesInCluster;
+
+    public RestPitSegmentsAction(Supplier<DiscoveryNodes> nodesInCluster) {
+        super();
+        this.nodesInCluster = nodesInCluster;
+    }
+
+    @Override
+    public List<RestHandler.Route> routes() {
+        return unmodifiableList(asList(new Route(GET, "/_cat/pit_segments/_all"), new Route(GET, "/_cat/pit_segments")));
+    }
+
+    @Override
+    public String getName() {
+        return "cat_pit_segments_action";
+    }
+
+    @Override
+    public boolean allowSystemIndexAccessByDefault() {
+        return true;
+    }
+
+    @Override
+    protected BaseRestHandler.RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
+        String allPitIdsQualifier = "_all";
+        final PitSegmentsRequest pitSegmentsRequest;
+        if (request.path().contains(allPitIdsQualifier)) {
+            pitSegmentsRequest = new PitSegmentsRequest(allPitIdsQualifier);
+        } else {
+            pitSegmentsRequest = new PitSegmentsRequest();
+            try {
+                request.withContentOrSourceParamParserOrNull((xContentParser -> {
+                    if (xContentParser != null) {
+                        pitSegmentsRequest.fromXContent(xContentParser);
+                    }
+                }));
+            } catch (IOException e) {
+                throw new IllegalArgumentException("Failed to parse request body", e);
+            }
+        }
+        return channel -> client.execute(PitSegmentsAction.INSTANCE, pitSegmentsRequest, new RestResponseListener<>(channel) {
+            @Override
+            public RestResponse buildResponse(final IndicesSegmentResponse indicesSegmentResponse) throws Exception {
+                final Map<String, IndexSegments> indicesSegments = indicesSegmentResponse.getIndices();
+                Table tab = buildTable(request, indicesSegments);
+                return RestTable.buildResponse(tab, channel);
+            }
+        });
+    }
+
+    @Override
+    protected void documentation(StringBuilder sb) {
+        sb.append("/_cat/pit_segments\n");
+        sb.append("/_cat/pit_segments/{pit_id}\n");
+    }
+
+    @Override
+    protected Table getTableWithHeader(RestRequest request) {
+        Table table = new Table();
+        table.startHeaders();
+        table.addCell("index", "default:true;alias:i,idx;desc:index name");
+        table.addCell("shard", "default:true;alias:s,sh;desc:shard name");
+        table.addCell("prirep", "alias:p,pr,primaryOrReplica;default:true;desc:primary or replica");
+        table.addCell("ip", "default:true;desc:ip of node where it lives");
+        table.addCell("id", "default:false;desc:unique id of node where it lives");
+        table.addCell("segment", "default:true;alias:seg;desc:segment name");
+        table.addCell("generation", "default:true;alias:g,gen;text-align:right;desc:segment generation");
+        table.addCell("docs.count", "default:true;alias:dc,docsCount;text-align:right;desc:number of docs in segment");
+        table.addCell("docs.deleted", "default:true;alias:dd,docsDeleted;text-align:right;desc:number of deleted docs in segment");
+        table.addCell("size", "default:true;alias:si;text-align:right;desc:segment size in bytes");
+        table.addCell("size.memory", "default:true;alias:sm,sizeMemory;text-align:right;desc:segment memory in bytes");
+        table.addCell("committed", "default:true;alias:ic,isCommitted;desc:is segment committed");
+        table.addCell("searchable", "default:true;alias:is,isSearchable;desc:is segment searched");
+        table.addCell("version", "default:true;alias:v,ver;desc:version");
+        table.addCell("compound", "default:true;alias:ico,isCompound;desc:is segment compound");
+        table.endHeaders();
+        return table;
+    }
+
+    private Table buildTable(final RestRequest request, Map<String, IndexSegments> indicesSegments) {
+        Table table = getTableWithHeader(request);
+
+        DiscoveryNodes nodes = this.nodesInCluster.get();
+
+        for (IndexSegments indexSegments : indicesSegments.values()) {
+            Map<Integer, IndexShardSegments> shards = indexSegments.getShards();
+            for (IndexShardSegments indexShardSegments : shards.values()) {
+                ShardSegments[] shardSegments = indexShardSegments.getShards();
+                for (ShardSegments shardSegment : shardSegments) {
+                    List<Segment> segments = shardSegment.getSegments();
+                    for (Segment segment : segments) {
+                        table.startRow();
+                        table.addCell(shardSegment.getShardRouting().getIndexName());
+                        table.addCell(shardSegment.getShardRouting().getId());
+                        table.addCell(shardSegment.getShardRouting().primary() ? "p" : "r");
+                        table.addCell(nodes.get(shardSegment.getShardRouting().currentNodeId()).getHostAddress());
+                        table.addCell(shardSegment.getShardRouting().currentNodeId());
+                        table.addCell(segment.getName());
+                        table.addCell(segment.getGeneration());
+                        table.addCell(segment.getNumDocs());
+                        table.addCell(segment.getDeletedDocs());
+                        table.addCell(segment.getSize());
+                        table.addCell(0L);
+                        table.addCell(segment.isCommitted());
+                        table.addCell(segment.isSearch());
+                        table.addCell(segment.getVersion());
+                        table.addCell(segment.isCompound());
+                        table.endRow();
+
+                    }
+                }
+            }
+        }
+        return table;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestPluginsAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestPluginsAction.java
index 79cac0f906c74..03a497574d9b3 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestPluginsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestPluginsAction.java
@@ -42,6 +42,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.plugins.PluginInfo;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -53,8 +54,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get plugin information
+ *
+ * @opensearch.api
+ */
 public class RestPluginsAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPluginsAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_cat/plugins"));
@@ -75,7 +83,10 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear().nodes(true);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
             @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestRepositoriesAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestRepositoriesAction.java
index fec3996506fca..c04c31b1580a6 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestRepositoriesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestRepositoriesAction.java
@@ -37,6 +37,7 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestResponseListener;
@@ -48,19 +49,26 @@
 
 /**
  * Cat API class to display information about snapshot repositories
+ *
+ * @opensearch.api
  */
 public class RestRepositoriesAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestRepositoriesAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(GET, "/_cat/repositories"));
     }
 
     @Override
-    protected RestChannelConsumer doCatRequest(RestRequest request, NodeClient client) {
+    public RestChannelConsumer doCatRequest(RestRequest request, NodeClient client) {
         GetRepositoriesRequest getRepositoriesRequest = new GetRepositoriesRequest();
         getRepositoriesRequest.local(request.paramAsBoolean("local", getRepositoriesRequest.local()));
-        getRepositoriesRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getRepositoriesRequest.masterNodeTimeout()));
+        getRepositoriesRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getRepositoriesRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getRepositoriesRequest, request);
 
         return channel -> client.admin()
             .cluster()
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestSegmentsAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestSegmentsAction.java
index 8d9d1937bdf56..68087d77fd326 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestSegmentsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestSegmentsAction.java
@@ -41,8 +41,9 @@
 import org.opensearch.action.admin.indices.segments.ShardSegments;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.engine.Segment;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -56,8 +57,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get segments information
+ *
+ * @opensearch.api
+ */
 public class RestSegmentsAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestSegmentsAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/segments"), new Route(GET, "/_cat/segments/{index}")));
@@ -74,12 +82,15 @@ public boolean allowSystemIndexAccessByDefault() {
     }
 
     @Override
-    protected RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
+    public RestChannelConsumer doCatRequest(final RestRequest request, final NodeClient client) {
         final String[] indices = Strings.splitStringByCommaToArray(request.param("index"));
 
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
         clusterStateRequest.clear().nodes(true).routingTable(true).indices(indices);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestShardsAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestShardsAction.java
index f9aa1a5554e9e..06b31270f7c65 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestShardsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestShardsAction.java
@@ -41,9 +41,11 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.engine.Engine;
@@ -73,8 +75,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get shard information
+ *
+ * @opensearch.api
+ */
 public class RestShardsAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestShardsAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/shards"), new Route(GET, "/_cat/shards/{index}")));
@@ -101,7 +110,10 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final String[] indices = Strings.splitStringByCommaToArray(request.param("index"));
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
         clusterStateRequest.clear().nodes(true).routingTable(true).indices(indices);
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
             @Override
@@ -208,12 +220,42 @@ protected Table getTableWithHeader(final RestRequest request) {
         table.addCell("search.query_current", "alias:sqc,searchQueryCurrent;default:false;text-align:right;desc:current query phase ops");
         table.addCell("search.query_time", "alias:sqti,searchQueryTime;default:false;text-align:right;desc:time spent in query phase");
         table.addCell("search.query_total", "alias:sqto,searchQueryTotal;default:false;text-align:right;desc:total query phase ops");
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            table.addCell(
+                "search.concurrent_query_current",
+                "alias:scqc,searchConcurrentQueryCurrent;default:false;text-align:right;desc:current concurrent query phase ops"
+            );
+            table.addCell(
+                "search.concurrent_query_time",
+                "alias:scqti,searchConcurrentQueryTime;default:false;text-align:right;desc:time spent in concurrent query phase"
+            );
+            table.addCell(
+                "search.concurrent_query_total",
+                "alias:scqto,searchConcurrentQueryTotal;default:false;text-align:right;desc:total concurrent query phase ops"
+            );
+            table.addCell(
+                "search.concurrent_avg_slice_count",
+                "alias:casc,searchConcurrentAvgSliceCount;default:false;text-align:right;desc:average query concurrency"
+            );
+        }
         table.addCell("search.scroll_current", "alias:scc,searchScrollCurrent;default:false;text-align:right;desc:open scroll contexts");
         table.addCell(
             "search.scroll_time",
             "alias:scti,searchScrollTime;default:false;text-align:right;desc:time scroll contexts held open"
         );
         table.addCell("search.scroll_total", "alias:scto,searchScrollTotal;default:false;text-align:right;desc:completed scroll contexts");
+        table.addCell(
+            "search.point_in_time_current",
+            "alias:spc,searchPointInTimeCurrent;default:false;text-align:right;desc:open point in time contexts"
+        );
+        table.addCell(
+            "search.point_in_time_time",
+            "alias:spti,searchPointInTimeTime;default:false;text-align:right;desc:time point in time contexts held open"
+        );
+        table.addCell(
+            "search.point_in_time_total",
+            "alias:spto,searchPointInTimeTotal;default:false;text-align:right;desc:completed point in time contexts"
+        );
 
         table.addCell("segments.count", "alias:sc,segmentsCount;default:false;text-align:right;desc:number of segments");
         table.addCell("segments.memory", "alias:sm,segmentsMemory;default:false;text-align:right;desc:memory used by segments");
@@ -376,9 +418,19 @@ Table buildTable(RestRequest request, ClusterStateResponse state, IndicesStatsRe
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getQueryCurrent()));
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getQueryTime()));
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getQueryCount()));
+            if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+                table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getConcurrentQueryCurrent()));
+                table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getConcurrentQueryTime()));
+                table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getConcurrentQueryCount()));
+                table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getConcurrentAvgSliceCount()));
+
+            }
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getScrollCurrent()));
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getScrollTime()));
             table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getScrollCount()));
+            table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getPitCurrent()));
+            table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getPitTime()));
+            table.addCell(getOrNull(commonStats, CommonStats::getSearch, i -> i.getTotal().getPitCount()));
 
             table.addCell(getOrNull(commonStats, CommonStats::getSegments, SegmentsStats::getCount));
             table.addCell(getOrNull(commonStats, CommonStats::getSegments, SegmentsStats::getZeroMemory));
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestSnapshotAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestSnapshotAction.java
index 55e20bc59aeac..8e97c753f6e44 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestSnapshotAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestSnapshotAction.java
@@ -36,6 +36,7 @@
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.rest.RestRequest;
@@ -55,9 +56,13 @@
 
 /**
  * Cat API class to display information about snapshots
+ *
+ * @opensearch.api
  */
 public class RestSnapshotAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestSnapshotAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/snapshots"), new Route(GET, "/_cat/snapshots/{repository}")));
@@ -69,13 +74,16 @@ public String getName() {
     }
 
     @Override
-    protected RestChannelConsumer doCatRequest(final RestRequest request, NodeClient client) {
+    public RestChannelConsumer doCatRequest(final RestRequest request, NodeClient client) {
         GetSnapshotsRequest getSnapshotsRequest = new GetSnapshotsRequest().repository(request.param("repository"))
             .snapshots(new String[] { GetSnapshotsRequest.ALL_SNAPSHOTS });
 
         getSnapshotsRequest.ignoreUnavailable(request.paramAsBoolean("ignore_unavailable", getSnapshotsRequest.ignoreUnavailable()));
 
-        getSnapshotsRequest.masterNodeTimeout(request.paramAsTime("master_timeout", getSnapshotsRequest.masterNodeTimeout()));
+        getSnapshotsRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", getSnapshotsRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(getSnapshotsRequest, request);
 
         return channel -> client.admin()
             .cluster()
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestTable.java b/server/src/main/java/org/opensearch/rest/action/cat/RestTable.java
index 69977cb73645a..4f1090b163ee6 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestTable.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestTable.java
@@ -33,22 +33,22 @@
 package org.opensearch.rest.action.cat;
 
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.UTF8StreamWriter;
-import org.opensearch.common.io.stream.BytesStream;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.SizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -60,17 +60,29 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * a REST table
+ *
+ * @opensearch.api
+ */
 public class RestTable {
 
     public static RestResponse buildResponse(Table table, RestChannel channel) throws Exception {
         RestRequest request = channel.request();
-        XContentType xContentType = XContentType.fromMediaTypeOrFormat(request.param("format", request.header("Accept")));
-        if (xContentType != null) {
+        MediaType mediaType = getXContentType(request);
+        if (mediaType != null) {
             return buildXContentBuilder(table, channel);
         }
         return buildTextPlainResponse(table, channel);
     }
 
+    private static MediaType getXContentType(RestRequest request) {
+        if (request.hasParam("format")) {
+            return MediaType.fromFormat(request.param("format"));
+        }
+        return MediaType.fromMediaType(request.header("Accept"));
+    }
+
     public static RestResponse buildXContentBuilder(Table table, RestChannel channel) throws Exception {
         RestRequest request = channel.request();
         XContentBuilder builder = channel.newBuilder();
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestTasksAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestTasksAction.java
index b87205593ce87..560b88787ae09 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestTasksAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestTasksAction.java
@@ -38,10 +38,10 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.Table;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.rest.action.RestResponseListener;
@@ -62,6 +62,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.action.admin.cluster.RestListTasksAction.generateListTasksRequest;
 
+/**
+ * _cat API action to get tasks information
+ *
+ * @opensearch.api
+ */
 public class RestTasksAction extends AbstractCatAction {
     private final Supplier<DiscoveryNodes> nodesInCluster;
 
@@ -137,6 +142,7 @@ protected Table getTableWithHeader(final RestRequest request) {
         // Task detailed info
         if (detailed) {
             table.addCell("description", "default:true;alias:desc;desc:task action");
+            table.addCell("resource_stats", "default:false;desc:resource consumption info of the task");
         }
         table.endHeaders();
         return table;
@@ -173,6 +179,7 @@ private void buildRow(Table table, boolean fullId, boolean detailed, DiscoveryNo
 
         if (detailed) {
             table.addCell(taskInfo.getDescription());
+            table.addCell(taskInfo.getResourceStats());
         }
         table.endRow();
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestTemplatesAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestTemplatesAction.java
index fcead3a34e8a9..d1b52cf2e4a5e 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestTemplatesAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestTemplatesAction.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.rest.action.cat;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
+import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -52,8 +52,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get template information
+ *
+ * @opensearch.api
+ */
 public class RestTemplatesAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestTemplatesAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/templates"), new Route(GET, "/_cat/templates/{name}")));
@@ -70,12 +77,15 @@ protected void documentation(StringBuilder sb) {
     }
 
     @Override
-    protected RestChannelConsumer doCatRequest(final RestRequest request, NodeClient client) {
+    public RestChannelConsumer doCatRequest(final RestRequest request, NodeClient client) {
         final String matchPattern = request.hasParam("name") ? request.param("name") : null;
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear().metadata(true);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestResponseListener<ClusterStateResponse>(channel) {
             @Override
@@ -101,8 +111,7 @@ protected Table getTableWithHeader(RestRequest request) {
     private Table buildTable(RestRequest request, ClusterStateResponse clusterStateResponse, String patternString) {
         Table table = getTableWithHeader(request);
         Metadata metadata = clusterStateResponse.getState().metadata();
-        for (ObjectObjectCursor<String, IndexTemplateMetadata> entry : metadata.templates()) {
-            IndexTemplateMetadata indexData = entry.value;
+        for (final IndexTemplateMetadata indexData : metadata.templates().values()) {
             if (patternString == null || Regex.simpleMatch(patternString, indexData.name())) {
                 table.startRow();
                 table.addCell(indexData.name());
diff --git a/server/src/main/java/org/opensearch/rest/action/cat/RestThreadPoolAction.java b/server/src/main/java/org/opensearch/rest/action/cat/RestThreadPoolAction.java
index 1198fe0bdcba3..7a6ff856fd2e9 100644
--- a/server/src/main/java/org/opensearch/rest/action/cat/RestThreadPoolAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/cat/RestThreadPoolAction.java
@@ -44,6 +44,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Table;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.monitor.process.ProcessInfo;
 import org.opensearch.rest.RestRequest;
@@ -66,8 +67,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * _cat API action to get threadpool information
+ *
+ * @opensearch.api
+ */
 public class RestThreadPoolAction extends AbstractCatAction {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestThreadPoolAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cat/thread_pool"), new Route(GET, "/_cat/thread_pool/{thread_pool_patterns}")));
@@ -89,7 +97,10 @@ public RestChannelConsumer doCatRequest(final RestRequest request, final NodeCli
         final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
         clusterStateRequest.clear().nodes(true);
         clusterStateRequest.local(request.paramAsBoolean("local", clusterStateRequest.local()));
-        clusterStateRequest.masterNodeTimeout(request.paramAsTime("master_timeout", clusterStateRequest.masterNodeTimeout()));
+        clusterStateRequest.clusterManagerNodeTimeout(
+            request.paramAsTime("cluster_manager_timeout", clusterStateRequest.clusterManagerNodeTimeout())
+        );
+        parseDeprecatedMasterTimeoutParameter(clusterStateRequest, request);
 
         return channel -> client.admin().cluster().state(clusterStateRequest, new RestActionListener<ClusterStateResponse>(channel) {
             @Override
@@ -152,6 +163,10 @@ protected Table getTableWithHeader(final RestRequest request) {
         table.addCell("rejected", "alias:r;default:true;text-align:right;desc:number of rejected tasks");
         table.addCell("largest", "alias:l;default:false;text-align:right;desc:highest number of seen active threads");
         table.addCell("completed", "alias:c;default:false;text-align:right;desc:number of completed tasks");
+        table.addCell(
+            "total_wait_time",
+            "alias:twt;default:false;text-align:right;desc:total time tasks spent waiting in thread_pool queue"
+        );
         table.addCell("core", "alias:cr;default:false;text-align:right;desc:core number of threads in a scaling thread pool");
         table.addCell("max", "alias:mx;default:false;text-align:right;desc:maximum number of threads in a scaling thread pool");
         table.addCell("size", "alias:sz;default:false;text-align:right;desc:number of threads in a fixed thread pool");
@@ -256,6 +271,7 @@ private Table buildTable(RestRequest req, ClusterStateResponse state, NodesInfoR
                 table.addCell(poolStats == null ? null : poolStats.getRejected());
                 table.addCell(poolStats == null ? null : poolStats.getLargest());
                 table.addCell(poolStats == null ? null : poolStats.getCompleted());
+                table.addCell(poolStats == null ? null : poolStats.getWaitTime());
                 table.addCell(core);
                 table.addCell(max);
                 table.addCell(size);
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestBulkAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestBulkAction.java
index c140514e3c92c..b046146707885 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestBulkAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestBulkAction.java
@@ -60,6 +60,8 @@
  * { "create" : { "_index" : "test", "_id" : "1" }
  * { "type1" : { "field1" : "value1" } }
  * </pre>
+ *
+ * @opensearch.api
  */
 public class RestBulkAction extends BaseRestHandler {
 
@@ -103,7 +105,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             defaultPipeline,
             defaultRequireAlias,
             allowExplicitIndex,
-            request.getXContentType()
+            request.getMediaType()
         );
 
         return channel -> client.bulk(bulkRequest, new RestStatusToXContentListener<>(channel));
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestDeleteAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestDeleteAction.java
index f9f5933a44c95..6b882369a883a 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestDeleteAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestDeleteAction.java
@@ -48,6 +48,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete a document
+ *
+ * @opensearch.api
+ */
 public class RestDeleteAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestGetAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestGetAction.java
index a0ec48ee55451..136a34789f4da 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestGetAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestGetAction.java
@@ -35,11 +35,11 @@
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.VersionType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestActions;
 import org.opensearch.rest.action.RestToXContentListener;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
@@ -49,11 +49,16 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
-import static org.opensearch.rest.RestStatus.OK;
 
+/**
+ * Transport action to get a document
+ *
+ * @opensearch.api
+ */
 public class RestGetAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestGetSourceAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestGetSourceAction.java
index 801ab85039d2d..9bbe081a44204 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestGetSourceAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestGetSourceAction.java
@@ -37,9 +37,9 @@
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
@@ -54,12 +54,14 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableList;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.HEAD;
-import static org.opensearch.rest.RestStatus.OK;
 
 /**
  * The REST handler for get source and head source APIs.
+ *
+ * @opensearch.api
  */
 public class RestGetSourceAction extends BaseRestHandler {
 
@@ -106,10 +108,10 @@ static class RestGetSourceResponseListener extends RestResponseListener<GetRespo
         public RestResponse buildResponse(final GetResponse response) throws Exception {
             checkResource(response);
 
-            final XContentBuilder builder = channel.newBuilder(request.getXContentType(), false);
+            final XContentBuilder builder = channel.newBuilder(request.getMediaType(), false);
             final BytesReference source = response.getSourceInternal();
             try (InputStream stream = source.streamInput()) {
-                builder.rawValue(stream, XContentHelper.xContentType(source));
+                builder.rawValue(stream, MediaTypeRegistry.xContentType(source));
             }
             return new BytesRestResponse(OK, builder);
         }
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestIndexAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestIndexAction.java
index 75f3967c32ba7..54448ef5c110c 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestIndexAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestIndexAction.java
@@ -54,6 +54,11 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to index a document
+ *
+ * @opensearch.api
+ */
 public class RestIndexAction extends BaseRestHandler {
 
     @Override
@@ -66,6 +71,11 @@ public String getName() {
         return "document_index_action";
     }
 
+    /**
+     * Create handler action.
+     *
+     * @opensearch.internal
+     */
     public static final class CreateHandler extends RestIndexAction {
 
         @Override
@@ -92,6 +102,11 @@ void validateOpType(String opType) {
         }
     }
 
+    /**
+     * The auto id handler.
+     *
+     * @opensearch.internal
+     */
     public static final class AutoIdHandler extends RestIndexAction {
 
         private final Supplier<DiscoveryNodes> nodesInCluster;
@@ -127,7 +142,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         indexRequest.id(request.param("id"));
         indexRequest.routing(request.param("routing"));
         indexRequest.setPipeline(request.param("pipeline"));
-        indexRequest.source(request.requiredContent(), request.getXContentType());
+        indexRequest.source(request.requiredContent(), request.getMediaType());
         indexRequest.timeout(request.paramAsTime("timeout", IndexRequest.DEFAULT_TIMEOUT));
         indexRequest.setRefreshPolicy(request.param("refresh"));
         indexRequest.version(RestActions.parseVersion(request));
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestMultiGetAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestMultiGetAction.java
index 6713bddfd837d..3190a016b613a 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestMultiGetAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestMultiGetAction.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -50,6 +50,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to perform a multi get
+ *
+ * @opensearch.api
+ */
 public class RestMultiGetAction extends BaseRestHandler {
     private final boolean allowExplicitIndex;
 
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestMultiTermVectorsAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestMultiTermVectorsAction.java
index 66b0c004b9fb4..67618ed8e5c2b 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestMultiTermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestMultiTermVectorsAction.java
@@ -35,7 +35,7 @@
 import org.opensearch.action.termvectors.MultiTermVectorsRequest;
 import org.opensearch.action.termvectors.TermVectorsRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -48,6 +48,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to get a multi term vector
+ *
+ * @opensearch.api
+ */
 public class RestMultiTermVectorsAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestTermVectorsAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestTermVectorsAction.java
index 727b90474082e..b7b75104adaad 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestTermVectorsAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestTermVectorsAction.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.termvectors.TermVectorsRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -55,6 +55,8 @@
 /**
  * This class parses the json request and translates it into a
  * TermVectorsRequest.
+ *
+ * @opensearch.api
  */
 public class RestTermVectorsAction extends BaseRestHandler {
     public static final String TYPES_DEPRECATION_MESSAGE = "[types removal] " + "Specifying types in term vector requests is deprecated.";
diff --git a/server/src/main/java/org/opensearch/rest/action/document/RestUpdateAction.java b/server/src/main/java/org/opensearch/rest/action/document/RestUpdateAction.java
index 832d8da4a8fdd..b3683e7b49fd7 100644
--- a/server/src/main/java/org/opensearch/rest/action/document/RestUpdateAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/document/RestUpdateAction.java
@@ -52,6 +52,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to update a document
+ *
+ * @opensearch.api
+ */
 public class RestUpdateAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/ingest/RestDeletePipelineAction.java b/server/src/main/java/org/opensearch/rest/action/ingest/RestDeletePipelineAction.java
index 179736b4b1816..21252e29ef5f6 100644
--- a/server/src/main/java/org/opensearch/rest/action/ingest/RestDeletePipelineAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/ingest/RestDeletePipelineAction.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.action.ingest.DeletePipelineRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -44,7 +45,14 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to delete an ingest pipeline
+ *
+ * @opensearch.api
+ */
 public class RestDeletePipelineAction extends BaseRestHandler {
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestDeletePipelineAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(DELETE, "/_ingest/pipeline/{id}"));
@@ -58,7 +66,8 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         DeletePipelineRequest request = new DeletePipelineRequest(restRequest.param("id"));
-        request.masterNodeTimeout(restRequest.paramAsTime("master_timeout", request.masterNodeTimeout()));
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
         request.timeout(restRequest.paramAsTime("timeout", request.timeout()));
         return channel -> client.admin().cluster().deletePipeline(request, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/ingest/RestGetPipelineAction.java b/server/src/main/java/org/opensearch/rest/action/ingest/RestGetPipelineAction.java
index cf86541ca8cd9..c6bdece0a7534 100644
--- a/server/src/main/java/org/opensearch/rest/action/ingest/RestGetPipelineAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/ingest/RestGetPipelineAction.java
@@ -34,7 +34,8 @@
 
 import org.opensearch.action.ingest.GetPipelineRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestStatusToXContentListener;
@@ -46,8 +47,15 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.GET;
 
+/**
+ * Transport action to get an ingest pipeline
+ *
+ * @opensearch.api
+ */
 public class RestGetPipelineAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestGetPipelineAction.class);
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_ingest/pipeline"), new Route(GET, "/_ingest/pipeline/{id}")));
@@ -61,7 +69,8 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         GetPipelineRequest request = new GetPipelineRequest(Strings.splitStringByCommaToArray(restRequest.param("id")));
-        request.masterNodeTimeout(restRequest.paramAsTime("master_timeout", request.masterNodeTimeout()));
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
         return channel -> client.admin().cluster().getPipeline(request, new RestStatusToXContentListener<>(channel));
     }
 }
diff --git a/server/src/main/java/org/opensearch/rest/action/ingest/RestPutPipelineAction.java b/server/src/main/java/org/opensearch/rest/action/ingest/RestPutPipelineAction.java
index 09f40c962dda7..13c5ee7a17644 100644
--- a/server/src/main/java/org/opensearch/rest/action/ingest/RestPutPipelineAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/ingest/RestPutPipelineAction.java
@@ -34,9 +34,10 @@
 
 import org.opensearch.action.ingest.PutPipelineRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -47,8 +48,15 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.rest.RestRequest.Method.PUT;
 
+/**
+ * Transport action to put a pipeline
+ *
+ * @opensearch.api
+ */
 public class RestPutPipelineAction extends BaseRestHandler {
 
+    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestPutPipelineAction.class);
+
     @Override
     public List<Route> routes() {
         return singletonList(new Route(PUT, "/_ingest/pipeline/{id}"));
@@ -61,9 +69,10 @@ public String getName() {
 
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
-        Tuple<XContentType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
+        Tuple<MediaType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
         PutPipelineRequest request = new PutPipelineRequest(restRequest.param("id"), sourceTuple.v2(), sourceTuple.v1());
-        request.masterNodeTimeout(restRequest.paramAsTime("master_timeout", request.masterNodeTimeout()));
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
         request.timeout(restRequest.paramAsTime("timeout", request.timeout()));
         return channel -> client.admin().cluster().putPipeline(request, new RestToXContentListener<>(channel));
     }
diff --git a/server/src/main/java/org/opensearch/rest/action/ingest/RestSimulatePipelineAction.java b/server/src/main/java/org/opensearch/rest/action/ingest/RestSimulatePipelineAction.java
index 1f8d9edce6eab..8a5aa539d02fa 100644
--- a/server/src/main/java/org/opensearch/rest/action/ingest/RestSimulatePipelineAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/ingest/RestSimulatePipelineAction.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.action.ingest.SimulatePipelineRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestToXContentListener;
@@ -49,6 +49,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to simulate an ingest pipeline
+ *
+ * @opensearch.api
+ */
 public class RestSimulatePipelineAction extends BaseRestHandler {
 
     @Override
@@ -70,7 +75,7 @@ public String getName() {
 
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
-        Tuple<XContentType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
+        Tuple<MediaType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
         SimulatePipelineRequest request = new SimulatePipelineRequest(sourceTuple.v2(), sourceTuple.v1());
         request.setId(restRequest.param("id"));
         request.setVerbose(restRequest.paramAsBoolean("verbose", false));
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestClearScrollAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestClearScrollAction.java
index 6bdbb47033859..04cfaacef5e76 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestClearScrollAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestClearScrollAction.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestStatusToXContentListener;
@@ -46,6 +46,11 @@
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.rest.RestRequest.Method.DELETE;
 
+/**
+ * Transport action to clear a scroll
+ *
+ * @opensearch.api
+ */
 public class RestClearScrollAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestCountAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestCountAction.java
index 6cb00633de441..acedd5a884596 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestCountAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestCountAction.java
@@ -36,8 +36,8 @@
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
@@ -57,6 +57,11 @@
 import static org.opensearch.rest.action.RestActions.buildBroadcastShardsHeader;
 import static org.opensearch.search.internal.SearchContext.DEFAULT_TERMINATE_AFTER;
 
+/**
+ * Transport action to count documents
+ *
+ * @opensearch.api
+ */
 public class RestCountAction extends BaseRestHandler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestCreatePitAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestCreatePitAction.java
new file mode 100644
index 0000000000000..2134087fc627b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestCreatePitAction.java
@@ -0,0 +1,57 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestStatusToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.POST;
+
+/**
+ * Rest action for creating PIT context
+ */
+public class RestCreatePitAction extends BaseRestHandler {
+    public static String ALLOW_PARTIAL_PIT_CREATION = "allow_partial_pit_creation";
+    public static String KEEP_ALIVE = "keep_alive";
+
+    @Override
+    public String getName() {
+        return "create_pit_action";
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        boolean allowPartialPitCreation = request.paramAsBoolean(ALLOW_PARTIAL_PIT_CREATION, true);
+        String[] indices = Strings.splitStringByCommaToArray(request.param("index"));
+        TimeValue keepAlive = request.paramAsTime(KEEP_ALIVE, null);
+        CreatePitRequest createPitRequest = new CreatePitRequest(keepAlive, allowPartialPitCreation, indices);
+        createPitRequest.setIndicesOptions(IndicesOptions.fromRequest(request, createPitRequest.indicesOptions()));
+        createPitRequest.setPreference(request.param("preference"));
+        createPitRequest.setRouting(request.param("routing"));
+
+        return channel -> client.createPit(createPitRequest, new RestStatusToXContentListener<>(channel));
+    }
+
+    @Override
+    public List<Route> routes() {
+        return unmodifiableList(asList(new Route(POST, "/{index}/_search/point_in_time")));
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestDeletePitAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestDeletePitAction.java
new file mode 100644
index 0000000000000..b19a7505741cc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestDeletePitAction.java
@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestStatusToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.DELETE;
+
+/**
+ * Rest action for deleting PIT contexts
+ */
+public class RestDeletePitAction extends BaseRestHandler {
+    @Override
+    public String getName() {
+        return "delete_pit_action";
+    }
+
+    @Override
+    public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        String allPitIdsQualifier = "_all";
+        final DeletePitRequest deletePITRequest;
+        if (request.path().contains(allPitIdsQualifier)) {
+            deletePITRequest = new DeletePitRequest(asList(allPitIdsQualifier));
+        } else {
+            deletePITRequest = new DeletePitRequest();
+            request.withContentOrSourceParamParserOrNull((xContentParser -> {
+                if (xContentParser != null) {
+                    try {
+                        deletePITRequest.fromXContent(xContentParser);
+                    } catch (IOException e) {
+                        throw new IllegalArgumentException("Failed to parse request body", e);
+                    }
+                }
+            }));
+        }
+        return channel -> client.deletePits(deletePITRequest, new RestStatusToXContentListener<DeletePitResponse>(channel));
+    }
+
+    @Override
+    public List<Route> routes() {
+        return unmodifiableList(asList(new Route(DELETE, "/_search/point_in_time"), new Route(DELETE, "/_search/point_in_time/_all")));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestDeleteSearchPipelineAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestDeleteSearchPipelineAction.java
new file mode 100644
index 0000000000000..ad669ed28d27f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestDeleteSearchPipelineAction.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.opensearch.rest.RestRequest.Method.DELETE;
+
+/**
+ * REST action to delete a search pipeline
+ *
+ *  @opensearch.internal
+ */
+public class RestDeleteSearchPipelineAction extends BaseRestHandler {
+    @Override
+    public String getName() {
+        return "search_delete_pipeline_action";
+    }
+
+    @Override
+    public List<Route> routes() {
+        return List.of(new Route(DELETE, "/_search/pipeline/{id}"));
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
+        DeleteSearchPipelineRequest request = new DeleteSearchPipelineRequest(restRequest.param("id"));
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
+        request.timeout(restRequest.paramAsTime("timeout", request.timeout()));
+        return channel -> client.admin().cluster().deleteSearchPipeline(request, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestExplainAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestExplainAction.java
index 2b73e145cf5ca..f63b54c0443d7 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestExplainAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestExplainAction.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.explain.ExplainRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -52,6 +52,8 @@
 
 /**
  * Rest action for computing a score explanation for specific documents.
+ *
+ * @opensearch.api
  */
 public class RestExplainAction extends BaseRestHandler {
 
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestGetAllPitsAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestGetAllPitsAction.java
new file mode 100644
index 0000000000000..809d65519c4f5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestGetAllPitsAction.java
@@ -0,0 +1,90 @@
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.GetAllPitNodesRequest;
+import org.opensearch.action.search.GetAllPitNodesResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestResponse;
+import org.opensearch.rest.action.RestBuilderListener;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Supplier;
+
+import static java.util.Collections.unmodifiableList;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * Rest action for retrieving all active PIT IDs across all nodes
+ */
+public class RestGetAllPitsAction extends BaseRestHandler {
+
+    private final Supplier<DiscoveryNodes> nodesInCluster;
+
+    public RestGetAllPitsAction(Supplier<DiscoveryNodes> nodesInCluster) {
+        super();
+        this.nodesInCluster = nodesInCluster;
+    }
+
+    @Override
+    public String getName() {
+        return "get_all_pit_action";
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+        final List<DiscoveryNode> nodes = new ArrayList<>();
+        for (DiscoveryNode node : nodesInCluster.get()) {
+            nodes.add(node);
+        }
+        DiscoveryNode[] disNodesArr = nodes.toArray(new DiscoveryNode[nodes.size()]);
+        GetAllPitNodesRequest getAllPitNodesRequest = new GetAllPitNodesRequest(disNodesArr);
+        return channel -> client.getAllPits(getAllPitNodesRequest, new RestBuilderListener<GetAllPitNodesResponse>(channel) {
+            @Override
+            public RestResponse buildResponse(final GetAllPitNodesResponse getAllPITNodesResponse, XContentBuilder builder)
+                throws Exception {
+                builder.startObject();
+                if (getAllPITNodesResponse.hasFailures()) {
+                    builder.startArray("failures");
+                    for (int idx = 0; idx < getAllPITNodesResponse.failures().size(); idx++) {
+                        builder.startObject();
+                        builder.field(
+                            getAllPITNodesResponse.failures().get(idx).nodeId(),
+                            getAllPITNodesResponse.failures().get(idx).getDetailedMessage()
+                        );
+                        builder.endObject();
+                    }
+                    builder.endArray();
+                }
+                builder.field("pits", getAllPITNodesResponse.getPitInfos());
+                builder.endObject();
+                if (getAllPITNodesResponse.hasFailures() && getAllPITNodesResponse.getPitInfos().isEmpty()) {
+                    return new BytesRestResponse(RestStatus.INTERNAL_SERVER_ERROR, builder);
+                }
+                return new BytesRestResponse(RestStatus.OK, builder);
+            }
+        });
+    }
+
+    @Override
+    public List<Route> routes() {
+        return unmodifiableList(Collections.singletonList(new Route(GET, "/_search/point_in_time/_all")));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestGetSearchPipelineAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestGetSearchPipelineAction.java
new file mode 100644
index 0000000000000..f377988d457b3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestGetSearchPipelineAction.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.GetSearchPipelineRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.common.Strings;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestStatusToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+/**
+ * REST action to retrieve search pipelines
+ *
+ *  @opensearch.internal
+ */
+public class RestGetSearchPipelineAction extends BaseRestHandler {
+    @Override
+    public String getName() {
+        return "search_get_pipeline_action";
+    }
+
+    @Override
+    public List<Route> routes() {
+        return List.of(new Route(GET, "/_search/pipeline"), new Route(GET, "/_search/pipeline/{id}"));
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
+        GetSearchPipelineRequest request = new GetSearchPipelineRequest(Strings.splitStringByCommaToArray(restRequest.param("id")));
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
+        return channel -> client.admin().cluster().getSearchPipeline(request, new RestStatusToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestMultiSearchAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestMultiSearchAction.java
index 8262f8199a704..4b11670450727 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestMultiSearchAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestMultiSearchAction.java
@@ -38,16 +38,16 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.CheckedBiConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestCancellableNodeClient;
@@ -66,6 +66,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to perform a multi search
+ *
+ * @opensearch.api
+ */
 public class RestMultiSearchAction extends BaseRestHandler {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestMultiSearchAction.class);
 
@@ -185,7 +190,7 @@ public static void parseMultiLineRequest(
         boolean ccsMinimizeRoundtrips = request.paramAsBoolean("ccs_minimize_roundtrips", true);
         String routing = request.param("routing");
 
-        final Tuple<XContentType, BytesReference> sourceTuple = request.contentOrSourceParam();
+        final Tuple<MediaType, BytesReference> sourceTuple = request.contentOrSourceParam();
         final XContent xContent = sourceTuple.v1().xContent();
         final BytesReference data = sourceTuple.v2();
         MultiSearchRequest.readMultiLineFormat(
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestPutSearchPipelineAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestPutSearchPipelineAction.java
new file mode 100644
index 0000000000000..463d5068d35ff
--- /dev/null
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestPutSearchPipelineAction.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.search;
+
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.RestToXContentListener;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.opensearch.rest.RestRequest.Method.PUT;
+
+/**
+ * REST action to put a search pipeline
+ *
+ * @opensearch.internal
+ */
+public class RestPutSearchPipelineAction extends BaseRestHandler {
+    @Override
+    public String getName() {
+        return "search_put_pipeline_action";
+    }
+
+    @Override
+    public List<Route> routes() {
+        return List.of(new Route(PUT, "/_search/pipeline/{id}"));
+    }
+
+    @Override
+    protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
+        Tuple<MediaType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
+        PutSearchPipelineRequest request = new PutSearchPipelineRequest(restRequest.param("id"), sourceTuple.v2(), sourceTuple.v1());
+        request.clusterManagerNodeTimeout(restRequest.paramAsTime("cluster_manager_timeout", request.clusterManagerNodeTimeout()));
+        parseDeprecatedMasterTimeoutParameter(request, restRequest);
+        request.timeout(restRequest.paramAsTime("timeout", request.timeout()));
+        return channel -> client.admin().cluster().putSearchPipeline(request, new RestToXContentListener<>(channel));
+    }
+}
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestSearchAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestSearchAction.java
index b84200407462f..ebfd082d974fd 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestSearchAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestSearchAction.java
@@ -40,9 +40,9 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
@@ -74,6 +74,11 @@
 import static org.opensearch.rest.RestRequest.Method.POST;
 import static org.opensearch.search.suggest.SuggestBuilders.termSuggestion;
 
+/**
+ * Transport action to perform a search
+ *
+ * @opensearch.api
+ */
 public class RestSearchAction extends BaseRestHandler {
     /**
      * Indicates whether hits.total should be rendered as an integer or an object
@@ -195,6 +200,7 @@ public static void parseSearchRequest(
         searchRequest.routing(request.param("routing"));
         searchRequest.preference(request.param("preference"));
         searchRequest.indicesOptions(IndicesOptions.fromRequest(request, searchRequest.indicesOptions()));
+        searchRequest.pipeline(request.param("search_pipeline"));
 
         checkRestTotalHits(request, searchRequest);
 
diff --git a/server/src/main/java/org/opensearch/rest/action/search/RestSearchScrollAction.java b/server/src/main/java/org/opensearch/rest/action/search/RestSearchScrollAction.java
index bb725c35e8799..28dc5f64763c2 100644
--- a/server/src/main/java/org/opensearch/rest/action/search/RestSearchScrollAction.java
+++ b/server/src/main/java/org/opensearch/rest/action/search/RestSearchScrollAction.java
@@ -50,6 +50,11 @@
 import static org.opensearch.rest.RestRequest.Method.GET;
 import static org.opensearch.rest.RestRequest.Method.POST;
 
+/**
+ * Transport action to perform a search scroll
+ *
+ * @opensearch.api
+ */
 public class RestSearchScrollAction extends BaseRestHandler {
     private static final Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TOTAL_HITS_AS_INT_PARAM);
 
diff --git a/server/src/main/java/org/opensearch/script/AbstractSortScript.java b/server/src/main/java/org/opensearch/script/AbstractSortScript.java
index d1a1b321b0ace..ac39be1074efa 100644
--- a/server/src/main/java/org/opensearch/script/AbstractSortScript.java
+++ b/server/src/main/java/org/opensearch/script/AbstractSortScript.java
@@ -46,10 +46,15 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Base sort script
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractSortScript implements ScorerAware {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
         deprecationLogger.deprecate(
             "sort-script_doc",
             "Accessing variable [doc] via [params.doc] from within an sort-script " + "is deprecated in favor of directly accessing [doc]."
diff --git a/server/src/main/java/org/opensearch/script/AggregationScript.java b/server/src/main/java/org/opensearch/script/AggregationScript.java
index c45541ff93658..ef300e9473d3e 100644
--- a/server/src/main/java/org/opensearch/script/AggregationScript.java
+++ b/server/src/main/java/org/opensearch/script/AggregationScript.java
@@ -46,6 +46,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Scripts for aggregations
+ *
+ * @opensearch.internal
+ */
 public abstract class AggregationScript implements ScorerAware {
 
     public static final String[] PARAMETERS = {};
@@ -53,7 +58,7 @@ public abstract class AggregationScript implements ScorerAware {
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("aggs", Factory.class);
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
         deprecationLogger.deprecate(
             "aggregation-script_doc",
             "Accessing variable [doc] via [params.doc] from within an aggregation-script "
@@ -162,6 +167,8 @@ public double runAsDouble() {
 
     /**
      * A factory to construct {@link AggregationScript} instances.
+     *
+     * @opensearch.internal
      */
     public interface LeafFactory {
         AggregationScript newInstance(LeafReaderContext ctx) throws IOException;
@@ -174,6 +181,8 @@ public interface LeafFactory {
 
     /**
      * A factory to construct stateful {@link AggregationScript} factories for a specific index.
+     *
+     * @opensearch.internal
      */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
diff --git a/server/src/main/java/org/opensearch/script/BucketAggregationScript.java b/server/src/main/java/org/opensearch/script/BucketAggregationScript.java
index b87cf85075d9e..55614e7fd7b9e 100644
--- a/server/src/main/java/org/opensearch/script/BucketAggregationScript.java
+++ b/server/src/main/java/org/opensearch/script/BucketAggregationScript.java
@@ -36,6 +36,8 @@
 
 /**
  * A script used in bucket aggregations that returns a {@code double} value.
+ *
+ * @opensearch.internal
  */
 public abstract class BucketAggregationScript {
 
@@ -61,6 +63,11 @@ public Map<String, Object> getParams() {
 
     public abstract Number execute();
 
+    /**
+     * Factory for bucket agg script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         BucketAggregationScript newInstance(Map<String, Object> params);
     }
diff --git a/server/src/main/java/org/opensearch/script/BucketAggregationSelectorScript.java b/server/src/main/java/org/opensearch/script/BucketAggregationSelectorScript.java
index 45c2df8a8394a..bc4ffbd57ebaa 100644
--- a/server/src/main/java/org/opensearch/script/BucketAggregationSelectorScript.java
+++ b/server/src/main/java/org/opensearch/script/BucketAggregationSelectorScript.java
@@ -36,6 +36,8 @@
 
 /**
  * A script used in bucket aggregations that returns a {@code boolean} value.
+ *
+ * @opensearch.internal
  */
 public abstract class BucketAggregationSelectorScript {
 
@@ -61,6 +63,11 @@ public Map<String, Object> getParams() {
 
     public abstract boolean execute();
 
+    /**
+     * Factory for bucket agg selector script
+     *
+     * @opensearch.internal
+     */
     public interface Factory {
         BucketAggregationSelectorScript newInstance(Map<String, Object> params);
     }
diff --git a/server/src/main/java/org/opensearch/script/ClassPermission.java b/server/src/main/java/org/opensearch/script/ClassPermission.java
index 0d3166403d5d1..9be8ecbc7c33e 100644
--- a/server/src/main/java/org/opensearch/script/ClassPermission.java
+++ b/server/src/main/java/org/opensearch/script/ClassPermission.java
@@ -85,6 +85,8 @@
  *   <li>{@link org.joda.time.ReadableDateTime}</li>
  *   <li>{@link org.joda.time.ReadableInstant}</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public final class ClassPermission extends BasicPermission {
     public static final String STANDARD = "<<STANDARD>>";
diff --git a/server/src/main/java/org/opensearch/script/DynamicMap.java b/server/src/main/java/org/opensearch/script/DynamicMap.java
index 4be4c8575ddae..985d454b0f87c 100644
--- a/server/src/main/java/org/opensearch/script/DynamicMap.java
+++ b/server/src/main/java/org/opensearch/script/DynamicMap.java
@@ -42,6 +42,8 @@
  * functions is provided for the overridden values where the function
  * is applied to the existing value when one exists for the
  * corresponding key.
+ *
+ * @opensearch.internal
  */
 public final class DynamicMap implements Map<String, Object> {
 
diff --git a/server/src/main/java/org/opensearch/script/ExplainableScoreScript.java b/server/src/main/java/org/opensearch/script/ExplainableScoreScript.java
index 6ea3a322449e5..fa6755953c8bd 100644
--- a/server/src/main/java/org/opensearch/script/ExplainableScoreScript.java
+++ b/server/src/main/java/org/opensearch/script/ExplainableScoreScript.java
@@ -41,6 +41,8 @@
  * To be implemented by {@link ScoreScript} which can provided an {@link Explanation} of the score
  * This is currently not used inside opensearch but it is used, see for example here:
  * https://github.com/elastic/elasticsearch/issues/8561
+ *
+ * @opensearch.internal
  */
 public interface ExplainableScoreScript {
 
diff --git a/server/src/main/java/org/opensearch/script/FieldScript.java b/server/src/main/java/org/opensearch/script/FieldScript.java
index aba3980facc93..82b5c9a088a2c 100644
--- a/server/src/main/java/org/opensearch/script/FieldScript.java
+++ b/server/src/main/java/org/opensearch/script/FieldScript.java
@@ -46,13 +46,15 @@
 
 /**
  * A script to produce dynamic values for return fields.
+ *
+ * @opensearch.internal
  */
 public abstract class FieldScript {
 
     public static final String[] PARAMETERS = {};
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
         deprecationLogger.deprecate(
             "field-script_doc",
             "Accessing variable [doc] via [params.doc] from within an field-script " + "is deprecated in favor of directly accessing [doc]."
@@ -108,11 +110,20 @@ public void setDocument(int docid) {
         leafLookup.setDocument(docid);
     }
 
-    /** A factory to construct {@link FieldScript} instances. */
+    /**
+     * A factory to construct {@link FieldScript} instances.
+     *
+     * @opensearch.internal
+     */
     public interface LeafFactory {
         FieldScript newInstance(LeafReaderContext ctx) throws IOException;
     }
 
+    /**
+     * Factory for field script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
     }
diff --git a/server/src/main/java/org/opensearch/script/FilterScript.java b/server/src/main/java/org/opensearch/script/FilterScript.java
index ffdf643606cb8..caba1c1e7d34a 100644
--- a/server/src/main/java/org/opensearch/script/FilterScript.java
+++ b/server/src/main/java/org/opensearch/script/FilterScript.java
@@ -42,6 +42,8 @@
 /**
  * A script implementation of a query filter.
  * See {@link org.opensearch.index.query.ScriptQueryBuilder}.
+ *
+ * @opensearch.internal
  */
 public abstract class FilterScript {
 
@@ -77,12 +79,20 @@ public void setDocument(int docid) {
         leafLookup.setDocument(docid);
     }
 
-    /** A factory to construct {@link FilterScript} instances. */
+    /**
+     * A factory to construct {@link FilterScript} instances.
+     *
+     * @opensearch.internal
+     */
     public interface LeafFactory {
         FilterScript newInstance(LeafReaderContext ctx) throws IOException;
     }
 
-    /** A factory to construct stateful {@link FilterScript} factories for a specific index. */
+    /**
+     * A factory to construct stateful {@link FilterScript} factories for a specific index.
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
     }
diff --git a/server/src/main/java/org/opensearch/script/GeneralScriptException.java b/server/src/main/java/org/opensearch/script/GeneralScriptException.java
index 86398bff990e7..ffc0c4d27d841 100644
--- a/server/src/main/java/org/opensearch/script/GeneralScriptException.java
+++ b/server/src/main/java/org/opensearch/script/GeneralScriptException.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
@@ -47,6 +47,8 @@
  * @deprecated Use ScriptException for exceptions from the scripting engine,
  *             otherwise use a more appropriate exception (e.g. if thrown
  *             from various abstractions)
+ *
+ * @opensearch.internal
  */
 @Deprecated
 public class GeneralScriptException extends OpenSearchException implements OpenSearchWrapperException {
diff --git a/server/src/main/java/org/opensearch/script/IngestConditionalScript.java b/server/src/main/java/org/opensearch/script/IngestConditionalScript.java
index c41fae1f759e8..2136a55cb69e8 100644
--- a/server/src/main/java/org/opensearch/script/IngestConditionalScript.java
+++ b/server/src/main/java/org/opensearch/script/IngestConditionalScript.java
@@ -38,6 +38,8 @@
 
 /**
  * A script used by {@link org.opensearch.ingest.ConditionalProcessor}.
+ *
+ * @opensearch.internal
  */
 public abstract class IngestConditionalScript {
 
@@ -66,6 +68,11 @@ public Map<String, Object> getParams() {
 
     public abstract boolean execute(Map<String, Object> ctx);
 
+    /**
+     * Factory for ingest condition script
+     *
+     * @opensearch.internal
+     */
     public interface Factory {
         IngestConditionalScript newInstance(Map<String, Object> params);
     }
diff --git a/server/src/main/java/org/opensearch/script/IngestScript.java b/server/src/main/java/org/opensearch/script/IngestScript.java
index 65a7bc1f3e52c..b427e09308573 100644
--- a/server/src/main/java/org/opensearch/script/IngestScript.java
+++ b/server/src/main/java/org/opensearch/script/IngestScript.java
@@ -38,6 +38,8 @@
 
 /**
  * A script used by the Ingest Script Processor.
+ *
+ * @opensearch.internal
  */
 public abstract class IngestScript {
 
@@ -66,6 +68,11 @@ public Map<String, Object> getParams() {
 
     public abstract void execute(Map<String, Object> ctx);
 
+    /**
+     * Factory for ingest script
+     *
+     * @opensearch.internal
+     */
     public interface Factory {
         IngestScript newInstance(Map<String, Object> params);
     }
diff --git a/server/src/main/java/org/opensearch/script/JodaCompatibleZonedDateTime.java b/server/src/main/java/org/opensearch/script/JodaCompatibleZonedDateTime.java
index a92d7c4cf45f7..7376f850c0b20 100644
--- a/server/src/main/java/org/opensearch/script/JodaCompatibleZonedDateTime.java
+++ b/server/src/main/java/org/opensearch/script/JodaCompatibleZonedDateTime.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.script;
 
-import org.joda.time.DateTime;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.SuppressLoggerChecks;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.common.time.DateUtils;
+import org.joda.time.DateTime;
 
 import java.security.AccessController;
 import java.security.PrivilegedAction;
@@ -69,6 +69,8 @@
 
 /**
  * A wrapper around ZonedDateTime that exposes joda methods for backcompat.
+ *
+ * @opensearch.internal
  */
 public class JodaCompatibleZonedDateTime
     implements
diff --git a/server/src/main/java/org/opensearch/script/NumberSortScript.java b/server/src/main/java/org/opensearch/script/NumberSortScript.java
index 4ce1cee6fed17..8d0eddc93842b 100644
--- a/server/src/main/java/org/opensearch/script/NumberSortScript.java
+++ b/server/src/main/java/org/opensearch/script/NumberSortScript.java
@@ -31,11 +31,17 @@
 
 package org.opensearch.script;
 
-import java.io.IOException;
-import java.util.Map;
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.search.lookup.SearchLookup;
 
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Script for number sorts
+ *
+ * @opensearch.internal
+ */
 public abstract class NumberSortScript extends AbstractSortScript {
 
     public static final String[] PARAMETERS = {};
@@ -54,6 +60,8 @@ protected NumberSortScript() {
 
     /**
      * A factory to construct {@link NumberSortScript} instances.
+     *
+     * @opensearch.internal
      */
     public interface LeafFactory {
         NumberSortScript newInstance(LeafReaderContext ctx) throws IOException;
@@ -66,6 +74,8 @@ public interface LeafFactory {
 
     /**
      * A factory to construct stateful {@link NumberSortScript} factories for a specific index.
+     *
+     * @opensearch.internal
      */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
diff --git a/server/src/main/java/org/opensearch/script/ScoreScript.java b/server/src/main/java/org/opensearch/script/ScoreScript.java
index 1f690faf2f68b..70de636a655f2 100644
--- a/server/src/main/java/org/opensearch/script/ScoreScript.java
+++ b/server/src/main/java/org/opensearch/script/ScoreScript.java
@@ -33,11 +33,14 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Explanation;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Scorable;
 import org.opensearch.Version;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.index.fielddata.ScriptDocValues;
+import org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName;
 import org.opensearch.search.lookup.LeafSearchLookup;
+import org.opensearch.search.lookup.LeafTermFrequencyLookup;
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.search.lookup.SourceLookup;
 
@@ -50,10 +53,16 @@
 
 /**
  * A script used for adjusting the score on a per document basis.
+ *
+ * @opensearch.internal
  */
 public abstract class ScoreScript {
 
-    /** A helper to take in an explanation from a script and turn it into an {@link org.apache.lucene.search.Explanation}  */
+    /**
+     * A helper to take in an explanation from a script and turn it into an {@link org.apache.lucene.search.Explanation}
+     *
+     * @opensearch.internal
+     */
     public static class ExplanationHolder {
         private String description;
 
@@ -78,7 +87,7 @@ public Explanation get(double score, Explanation subQueryExplanation) {
     }
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
         deprecationLogger.deprecate(
             "score-script_doc",
             "Accessing variable [doc] via [params.doc] from within an score-script " + "is deprecated in favor of directly accessing [doc]."
@@ -101,6 +110,9 @@ public Explanation get(double score, Explanation subQueryExplanation) {
     /** A leaf lookup for the bound segment this script will operate on. */
     private final LeafSearchLookup leafLookup;
 
+    /** A leaf term frequency lookup for the bound segment this script will operate on. */
+    private final LeafTermFrequencyLookup leafTermFrequencyLookup;
+
     private DoubleSupplier scoreSupplier = () -> 0.0;
 
     private final int docBase;
@@ -109,16 +121,18 @@ public Explanation get(double score, Explanation subQueryExplanation) {
     private String indexName = null;
     private Version indexVersion = null;
 
-    public ScoreScript(Map<String, Object> params, SearchLookup lookup, LeafReaderContext leafContext) {
+    public ScoreScript(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher, LeafReaderContext leafContext) {
         // null check needed b/c of expression engine subclass
         if (lookup == null) {
             assert params == null;
             assert leafContext == null;
             this.params = null;
             this.leafLookup = null;
+            this.leafTermFrequencyLookup = null;
             this.docBase = 0;
         } else {
             this.leafLookup = lookup.getLeafSearchLookup(leafContext);
+            this.leafTermFrequencyLookup = new LeafTermFrequencyLookup(indexSearcher, leafLookup);
             params = new HashMap<>(params);
             params.putAll(leafLookup.asMap());
             this.params = new DynamicMap(params, PARAMS_FUNCTIONS);
@@ -138,6 +152,10 @@ public Map<String, ScriptDocValues<?>> getDoc() {
         return leafLookup.doc();
     }
 
+    public Object getTermFrequency(TermFrequencyFunctionName functionName, String field, String val) throws IOException {
+        return leafTermFrequencyLookup.getTermFrequency(functionName, field, val, docId);
+    }
+
     /** Set the current document to run the script on next. */
     public void setDocument(int docid) {
         this.docId = docid;
@@ -240,7 +258,11 @@ public void _setIndexVersion(Version indexVersion) {
         this.indexVersion = indexVersion;
     }
 
-    /** A factory to construct {@link ScoreScript} instances. */
+    /**
+     * A factory to construct {@link ScoreScript} instances.
+     *
+     * @opensearch.internal
+     */
     public interface LeafFactory {
 
         /**
@@ -251,10 +273,14 @@ public interface LeafFactory {
         ScoreScript newInstance(LeafReaderContext ctx) throws IOException;
     }
 
-    /** A factory to construct stateful {@link ScoreScript} factories for a specific index. */
+    /**
+     * A factory to construct stateful {@link ScoreScript} factories for a specific index.
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
 
-        ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
+        ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher);
 
     }
 
diff --git a/server/src/main/java/org/opensearch/script/ScoreScriptUtils.java b/server/src/main/java/org/opensearch/script/ScoreScriptUtils.java
index ed9d4e6c4f8a7..141e4e21b647a 100644
--- a/server/src/main/java/org/opensearch/script/ScoreScriptUtils.java
+++ b/server/src/main/java/org/opensearch/script/ScoreScriptUtils.java
@@ -46,8 +46,16 @@
 
 import java.time.ZoneId;
 
-import static com.carrotsearch.hppc.BitMixer.mix32;
+import static org.opensearch.common.util.BitMixer.mix32;
+import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.SUM_TOTAL_TERM_FREQ;
+import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.TERM_FREQ;
+import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.TOTAL_TERM_FREQ;
 
+/**
+ * Utilities for scoring scripts
+ *
+ * @opensearch.internal
+ */
 public final class ScoreScriptUtils {
 
     /****** STATIC FUNCTIONS that can be used by users for score calculations **/
@@ -64,7 +72,74 @@ public static double sigmoid(double value, double k, double a) {
         return Math.pow(value, a) / (Math.pow(k, a) + Math.pow(value, a));
     }
 
-    // random score based on the documents' values of the given field
+    /**
+     * Retrieves the term frequency within a field for a specific term.
+     *
+     * @opensearch.internal
+     */
+    public static final class TermFreq {
+        private final ScoreScript scoreScript;
+
+        public TermFreq(ScoreScript scoreScript) {
+            this.scoreScript = scoreScript;
+        }
+
+        public int termFreq(String field, String term) {
+            try {
+                return (int) scoreScript.getTermFrequency(TERM_FREQ, field, term);
+            } catch (Exception e) {
+                throw ExceptionsHelper.convertToOpenSearchException(e);
+            }
+        }
+    }
+
+    /**
+     * Retrieves the total term frequency within a field for a specific term.
+     *
+     * @opensearch.internal
+     */
+    public static final class TotalTermFreq {
+        private final ScoreScript scoreScript;
+
+        public TotalTermFreq(ScoreScript scoreScript) {
+            this.scoreScript = scoreScript;
+        }
+
+        public long totalTermFreq(String field, String term) {
+            try {
+                return (long) scoreScript.getTermFrequency(TOTAL_TERM_FREQ, field, term);
+            } catch (Exception e) {
+                throw ExceptionsHelper.convertToOpenSearchException(e);
+            }
+        }
+    }
+
+    /**
+     * Retrieves the sum of total term frequencies within a field.
+     *
+     * @opensearch.internal
+     */
+    public static final class SumTotalTermFreq {
+        private final ScoreScript scoreScript;
+
+        public SumTotalTermFreq(ScoreScript scoreScript) {
+            this.scoreScript = scoreScript;
+        }
+
+        public long sumTotalTermFreq(String field) {
+            try {
+                return (long) scoreScript.getTermFrequency(SUM_TOTAL_TERM_FREQ, field, null);
+            } catch (Exception e) {
+                throw ExceptionsHelper.convertToOpenSearchException(e);
+            }
+        }
+    }
+
+    /**
+     * random score based on the documents' values of the given field
+     *
+     * @opensearch.internal
+     */
     public static final class RandomScoreField {
         private final ScoreScript scoreScript;
         private final ScriptDocValues docValues;
@@ -90,7 +165,11 @@ public double randomScore() {
         }
     }
 
-    // random score based on the internal Lucene document Ids
+    /**
+     * random score based on the internal Lucene document Ids
+     *
+     * @opensearch.internal
+     */
     public static final class RandomScoreDoc {
         private final ScoreScript scoreScript;
         private final int saltedSeed;
@@ -108,7 +187,11 @@ public double randomScore() {
         }
     }
 
-    // **** Decay functions on geo field
+    /**
+     * **** Decay functions on geo field
+     *
+     * @opensearch.internal
+     */
     public static final class DecayGeoLinear {
         // cached variables calculated once per script execution
         double originLat;
@@ -132,6 +215,11 @@ public double decayGeoLinear(GeoPoint docValue) {
         }
     }
 
+    /**
+     * Exponential geo decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayGeoExp {
         double originLat;
         double originLon;
@@ -154,6 +242,11 @@ public double decayGeoExp(GeoPoint docValue) {
         }
     }
 
+    /**
+     * Gaussian geo decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayGeoGauss {
         double originLat;
         double originLon;
@@ -178,6 +271,11 @@ public double decayGeoGauss(GeoPoint docValue) {
 
     // **** Decay functions on numeric field
 
+    /**
+     * Linear numeric decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayNumericLinear {
         double origin;
         double offset;
@@ -195,6 +293,11 @@ public double decayNumericLinear(double docValue) {
         }
     }
 
+    /**
+     * Exponential numeric decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayNumericExp {
         double origin;
         double offset;
@@ -212,6 +315,11 @@ public double decayNumericExp(double docValue) {
         }
     }
 
+    /**
+     * Gaussian numeric decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayNumericGauss {
         double origin;
         double offset;
@@ -240,6 +348,11 @@ public double decayNumericGauss(double docValue) {
     private static final ZoneId defaultZoneId = ZoneId.of("UTC");
     private static final DateMathParser dateParser = DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.toDateMathParser();
 
+    /**
+     * Linear date decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayDateLinear {
         long origin;
         long offset;
@@ -263,6 +376,11 @@ public double decayDateLinear(JodaCompatibleZonedDateTime docValueDate) {
         }
     }
 
+    /**
+     * Exponential date decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayDateExp {
         long origin;
         long offset;
@@ -285,6 +403,11 @@ public double decayDateExp(JodaCompatibleZonedDateTime docValueDate) {
         }
     }
 
+    /**
+     * Gaussian date decay
+     *
+     * @opensearch.internal
+     */
     public static final class DecayDateGauss {
         long origin;
         long offset;
diff --git a/server/src/main/java/org/opensearch/script/Script.java b/server/src/main/java/org/opensearch/script/Script.java
index 561324e24bd07..a611e71c3bf3f 100644
--- a/server/src/main/java/org/opensearch/script/Script.java
+++ b/server/src/main/java/org/opensearch/script/Script.java
@@ -33,28 +33,29 @@
 package org.opensearch.script;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.AbstractObjectParser;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -95,7 +96,10 @@
  *                                use an empty {@link Map} to specify no params
  * </ul>
  * </ul>
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class Script implements ToXContentObject, Writeable {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(Script.class);
@@ -179,8 +183,8 @@ private void setInline(XContentParser parser) {
                 if (parser.currentToken() == Token.START_OBJECT) {
                     // this is really for search templates, that need to be converted to json format
                     XContentBuilder builder = XContentFactory.jsonBuilder();
-                    idOrCode = Strings.toString(builder.copyCurrentStructure(parser));
-                    options.put(CONTENT_TYPE_OPTION, XContentType.JSON.mediaType());
+                    idOrCode = builder.copyCurrentStructure(parser).toString();
+                    options.put(CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType());
                 } else {
                     idOrCode = parser.text();
                 }
diff --git a/server/src/main/java/org/opensearch/script/ScriptCache.java b/server/src/main/java/org/opensearch/script/ScriptCache.java
index 71476ce55d661..3c50fc12dcacb 100644
--- a/server/src/main/java/org/opensearch/script/ScriptCache.java
+++ b/server/src/main/java/org/opensearch/script/ScriptCache.java
@@ -34,14 +34,14 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.cache.Cache;
 import org.opensearch.common.cache.CacheBuilder;
 import org.opensearch.common.cache.RemovalListener;
 import org.opensearch.common.cache.RemovalNotification;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
 
 import java.util.Map;
 import java.util.Objects;
@@ -50,6 +50,8 @@
 
 /**
  * Script cache and compilation rate limiter.
+ *
+ * @opensearch.internal
  */
 public class ScriptCache {
 
@@ -262,6 +264,11 @@ private TokenBucketState(long lastInlineCompileTime, double availableTokens, boo
         }
     }
 
+    /**
+     * Tracking compilation rate
+     *
+     * @opensearch.internal
+     */
     public static class CompilationRate {
         public final int count;
         public final TimeValue time;
diff --git a/server/src/main/java/org/opensearch/script/ScriptCacheStats.java b/server/src/main/java/org/opensearch/script/ScriptCacheStats.java
index 97bf6aa443b0d..be7a1c9542a60 100644
--- a/server/src/main/java/org/opensearch/script/ScriptCacheStats.java
+++ b/server/src/main/java/org/opensearch/script/ScriptCacheStats.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -45,7 +45,14 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
-// This class is deprecated in favor of ScriptStats and ScriptContextStats.  It is removed in 8.
+/**
+ * Stats for script caching
+ *
+ * @opensearch.internal
+ *
+ * @deprecated This class is deprecated in favor of ScriptStats and ScriptContextStats.  It is removed in OpenSearch 2.0.
+ */
+@Deprecated
 public class ScriptCacheStats implements Writeable, ToXContentFragment {
     private final Map<String, ScriptStats> context;
     private final ScriptStats general;
diff --git a/server/src/main/java/org/opensearch/script/ScriptContext.java b/server/src/main/java/org/opensearch/script/ScriptContext.java
index 299528494f7dc..71ced303b062e 100644
--- a/server/src/main/java/org/opensearch/script/ScriptContext.java
+++ b/server/src/main/java/org/opensearch/script/ScriptContext.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.script;
 
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.unit.TimeValue;
 
@@ -69,7 +70,10 @@
  * For example, to check if a variable {@code doc} is used, a method {@code boolean needsDoc()} should be added.
  * If the variable name starts with an underscore, for example, {@code _score}, the needs method would
  * be {@code boolean needs_score()}.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public final class ScriptContext<FactoryType> {
 
     /** A unique identifier for this context. */
diff --git a/server/src/main/java/org/opensearch/script/ScriptContextInfo.java b/server/src/main/java/org/opensearch/script/ScriptContextInfo.java
index 360ef93868722..d3a64c207e0ce 100644
--- a/server/src/main/java/org/opensearch/script/ScriptContextInfo.java
+++ b/server/src/main/java/org/opensearch/script/ScriptContextInfo.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.lang.reflect.Field;
@@ -55,8 +55,13 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Information about a script context
+ *
+ * @opensearch.internal
+ */
 public class ScriptContextInfo implements ToXContentObject, Writeable {
     public final String name;
     public final ScriptMethodInfo execute;
@@ -194,6 +199,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder.endArray().endObject();
     }
 
+    /**
+     * Script method information
+     *
+     * @opensearch.internal
+     */
     public static class ScriptMethodInfo implements ToXContentObject, Writeable {
         public final String name, returnType;
         public final List<ParameterInfo> parameters;
@@ -272,6 +282,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             return builder.endArray().endObject();
         }
 
+        /**
+         * Parameter information
+         *
+         * @opensearch.internal
+         */
         public static class ParameterInfo implements ToXContentObject, Writeable {
             public final String type, name;
 
diff --git a/server/src/main/java/org/opensearch/script/ScriptContextStats.java b/server/src/main/java/org/opensearch/script/ScriptContextStats.java
index 345b5193a29d7..16f4a7e313326 100644
--- a/server/src/main/java/org/opensearch/script/ScriptContextStats.java
+++ b/server/src/main/java/org/opensearch/script/ScriptContextStats.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Stats for a script context
+ *
+ * @opensearch.internal
+ */
 public class ScriptContextStats implements Writeable, ToXContentFragment, Comparable<ScriptContextStats> {
     private final String context;
     private final long compilations;
diff --git a/server/src/main/java/org/opensearch/script/ScriptEngine.java b/server/src/main/java/org/opensearch/script/ScriptEngine.java
index 35cc0a55237e4..560727bc8fa97 100644
--- a/server/src/main/java/org/opensearch/script/ScriptEngine.java
+++ b/server/src/main/java/org/opensearch/script/ScriptEngine.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.script;
 
+import org.opensearch.common.annotation.PublicApi;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Map;
@@ -39,7 +41,10 @@
 
 /**
  * A script language implementation.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public interface ScriptEngine extends Closeable {
 
     /**
diff --git a/server/src/main/java/org/opensearch/script/ScriptException.java b/server/src/main/java/org/opensearch/script/ScriptException.java
index d053d3567610e..1eef8868b675c 100644
--- a/server/src/main/java/org/opensearch/script/ScriptException.java
+++ b/server/src/main/java/org/opensearch/script/ScriptException.java
@@ -34,13 +34,12 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -59,6 +58,8 @@
  *   <li>{@code script}: Identifier for which script failed.
  *   <li>{@code lang}: Scripting engine language, such as "painless"
  * </ul>
+ *
+ * @opensearch.internal
  */
 @SuppressWarnings("serial")
 public class ScriptException extends OpenSearchException {
@@ -175,7 +176,7 @@ public String toJsonString() {
             json.startObject();
             toXContent(json, ToXContent.EMPTY_PARAMS);
             json.endObject();
-            return Strings.toString(json);
+            return json.toString();
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
@@ -186,6 +187,11 @@ public RestStatus status() {
         return RestStatus.BAD_REQUEST;
     }
 
+    /**
+     * Position data
+     *
+     * @opensearch.internal
+     */
     public static class Position {
         public final int offset;
         public final int start;
diff --git a/server/src/main/java/org/opensearch/script/ScriptFactory.java b/server/src/main/java/org/opensearch/script/ScriptFactory.java
index 6366d5dbc9287..96cba8aa66a2c 100644
--- a/server/src/main/java/org/opensearch/script/ScriptFactory.java
+++ b/server/src/main/java/org/opensearch/script/ScriptFactory.java
@@ -34,6 +34,8 @@
 
 /**
  * Contains utility methods for compiled scripts without impacting concrete script signatures
+ *
+ * @opensearch.internal
  */
 public interface ScriptFactory {
     /** Returns {@code true} if the result of the script will be deterministic, {@code false} otherwise. */
diff --git a/server/src/main/java/org/opensearch/script/ScriptLanguagesInfo.java b/server/src/main/java/org/opensearch/script/ScriptLanguagesInfo.java
index acc26530211c0..ef64959f99a3c 100644
--- a/server/src/main/java/org/opensearch/script/ScriptLanguagesInfo.java
+++ b/server/src/main/java/org/opensearch/script/ScriptLanguagesInfo.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -51,7 +51,7 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * The allowable types, languages and their corresponding contexts.  When serialized there is a top level <code>types_allowed</code> list,
@@ -90,6 +90,8 @@
  *   ]
  * }
  * </code>
+ *
+ * @opensearch.internal
  */
 public class ScriptLanguagesInfo implements ToXContentObject, Writeable {
     private static final ParseField TYPES_ALLOWED = new ParseField("types_allowed");
diff --git a/server/src/main/java/org/opensearch/script/ScriptMetadata.java b/server/src/main/java/org/opensearch/script/ScriptMetadata.java
index 4fde74adbdf41..5f529fccd213c 100644
--- a/server/src/main/java/org/opensearch/script/ScriptMetadata.java
+++ b/server/src/main/java/org/opensearch/script/ScriptMetadata.java
@@ -38,15 +38,15 @@
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.NamedDiff;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -57,6 +57,8 @@
 /**
  * {@link ScriptMetadata} is used to store user-defined scripts
  * as part of the {@link ClusterState} using only an id as the key.
+ *
+ * @opensearch.internal
  */
 public final class ScriptMetadata implements Metadata.Custom, Writeable, ToXContentFragment {
 
@@ -70,6 +72,8 @@ public final class ScriptMetadata implements Metadata.Custom, Writeable, ToXCont
      * the {@link ClusterState}.  Scripts can be added or deleted, then built
      * to generate a new {@link Map} of scripts that will be used to update
      * the current {@link ClusterState}.
+     *
+     * @opensearch.internal
      */
     public static final class Builder {
 
diff --git a/server/src/main/java/org/opensearch/script/ScriptMetrics.java b/server/src/main/java/org/opensearch/script/ScriptMetrics.java
index 2a7ccd0a781f0..fd54c757fd017 100644
--- a/server/src/main/java/org/opensearch/script/ScriptMetrics.java
+++ b/server/src/main/java/org/opensearch/script/ScriptMetrics.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.metrics.CounterMetric;
 
+/**
+ * Metrics for scripts
+ *
+ * @opensearch.internal
+ */
 public class ScriptMetrics {
     final CounterMetric compilationsMetric = new CounterMetric();
     final CounterMetric cacheEvictionsMetric = new CounterMetric();
diff --git a/server/src/main/java/org/opensearch/script/ScriptModule.java b/server/src/main/java/org/opensearch/script/ScriptModule.java
index 5ccf16bf38457..a192e9553016b 100644
--- a/server/src/main/java/org/opensearch/script/ScriptModule.java
+++ b/server/src/main/java/org/opensearch/script/ScriptModule.java
@@ -48,6 +48,8 @@
 
 /**
  * Manages building {@link ScriptService}.
+ *
+ * @opensearch.internal
  */
 public class ScriptModule {
 
@@ -66,6 +68,7 @@ public class ScriptModule {
             SignificantTermsHeuristicScoreScript.CONTEXT,
             IngestScript.CONTEXT,
             IngestConditionalScript.CONTEXT,
+            SearchScript.CONTEXT,
             FilterScript.CONTEXT,
             SimilarityScript.CONTEXT,
             SimilarityWeightScript.CONTEXT,
diff --git a/server/src/main/java/org/opensearch/script/ScriptService.java b/server/src/main/java/org/opensearch/script/ScriptService.java
index 7be41dcd242f0..d3c8861dbc5d7 100644
--- a/server/src/main/java/org/opensearch/script/ScriptService.java
+++ b/server/src/main/java/org/opensearch/script/ScriptService.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.storedscripts.DeleteStoredScriptRequest;
 import org.opensearch.action.admin.cluster.storedscripts.GetStoredScriptRequest;
 import org.opensearch.action.admin.cluster.storedscripts.PutStoredScriptRequest;
@@ -45,14 +44,17 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -71,6 +73,12 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * Service for scripting
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class ScriptService implements Closeable, ClusterStateApplier {
 
     private static final Logger logger = LogManager.getLogger(ScriptService.class);
@@ -540,6 +548,7 @@ protected StoredScriptSource getScriptFromClusterState(String id) {
     public void putStoredScript(
         ClusterService clusterService,
         PutStoredScriptRequest request,
+        ClusterManagerTaskThrottler.ThrottlingKey putStoreTaskKey,
         ActionListener<AcknowledgedResponse> listener
     ) {
         if (request.content().length() > maxSizeInBytes) {
@@ -599,6 +608,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
 
                     return ClusterState.builder(currentState).metadata(mdb).build();
                 }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return putStoreTaskKey;
+                }
             }
         );
     }
@@ -606,6 +620,7 @@ public ClusterState execute(ClusterState currentState) throws Exception {
     public void deleteStoredScript(
         ClusterService clusterService,
         DeleteStoredScriptRequest request,
+        ClusterManagerTaskThrottler.ThrottlingKey deleteScriptTaskKey,
         ActionListener<AcknowledgedResponse> listener
     ) {
         clusterService.submitStateUpdateTask(
@@ -625,6 +640,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
 
                     return ClusterState.builder(currentState).metadata(mdb).build();
                 }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return deleteScriptTaskKey;
+                }
             }
         );
     }
diff --git a/server/src/main/java/org/opensearch/script/ScriptStats.java b/server/src/main/java/org/opensearch/script/ScriptStats.java
index 31ce0683b36d8..e029f2383292e 100644
--- a/server/src/main/java/org/opensearch/script/ScriptStats.java
+++ b/server/src/main/java/org/opensearch/script/ScriptStats.java
@@ -33,11 +33,11 @@
 package org.opensearch.script;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -46,6 +46,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Stats for scripts
+ *
+ * @opensearch.internal
+ */
 public class ScriptStats implements Writeable, ToXContentFragment {
     private final List<ScriptContextStats> contextStats;
     private final long compilations;
diff --git a/server/src/main/java/org/opensearch/script/ScriptType.java b/server/src/main/java/org/opensearch/script/ScriptType.java
index 29a6cceef5561..c39edcbcb12c4 100644
--- a/server/src/main/java/org/opensearch/script/ScriptType.java
+++ b/server/src/main/java/org/opensearch/script/ScriptType.java
@@ -32,10 +32,11 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.PublicApi;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -44,7 +45,10 @@
  * ScriptType represents the way a script is stored and retrieved from the {@link ScriptService}.
  * It's also used to by {@link ScriptService} to determine whether or not a {@link Script} is
  * allowed to be executed based on both default and user-defined settings.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public enum ScriptType implements Writeable {
 
     /**
diff --git a/server/src/main/java/org/opensearch/script/ScriptedMetricAggContexts.java b/server/src/main/java/org/opensearch/script/ScriptedMetricAggContexts.java
index 1f187f7f0e8f5..2f61fd75471ad 100644
--- a/server/src/main/java/org/opensearch/script/ScriptedMetricAggContexts.java
+++ b/server/src/main/java/org/opensearch/script/ScriptedMetricAggContexts.java
@@ -47,8 +47,18 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Contexts for scripted metric aggregations
+ *
+ * @opensearch.internal
+ */
 public class ScriptedMetricAggContexts {
 
+    /**
+     * Base initialization script
+     *
+     * @opensearch.internal
+     */
     public abstract static class InitScript {
         private final Map<String, Object> params;
         private final Map<String, Object> state;
@@ -68,6 +78,11 @@ public Object getState() {
 
         public abstract void execute();
 
+        /**
+         * Factory for a scripted metric agg context
+         *
+         * @opensearch.internal
+         */
         public interface Factory extends ScriptFactory {
             InitScript newInstance(Map<String, Object> params, Map<String, Object> state);
         }
@@ -76,10 +91,15 @@ public interface Factory extends ScriptFactory {
         public static ScriptContext<Factory> CONTEXT = new ScriptContext<>("aggs_init", Factory.class);
     }
 
+    /**
+     * Base map script
+     *
+     * @opensearch.internal
+     */
     public abstract static class MapScript {
 
         private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-        private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+        private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
             deprecationLogger.deprecate(
                 "map-script_doc",
                 "Accessing variable [doc] via [params.doc] from within an scripted metric agg map script "
@@ -157,10 +177,20 @@ public double get_score() {
 
         public abstract void execute();
 
+        /**
+         * Factory for a scripted metric agg context
+         *
+         * @opensearch.internal
+         */
         public interface LeafFactory {
             MapScript newInstance(LeafReaderContext ctx);
         }
 
+        /**
+         * Factory for a scripted metric agg factory
+         *
+         * @opensearch.internal
+         */
         public interface Factory extends ScriptFactory {
             LeafFactory newFactory(Map<String, Object> params, Map<String, Object> state, SearchLookup lookup);
         }
@@ -169,6 +199,11 @@ public interface Factory extends ScriptFactory {
         public static ScriptContext<Factory> CONTEXT = new ScriptContext<>("aggs_map", Factory.class);
     }
 
+    /**
+     * Base combination script
+     *
+     * @opensearch.internal
+     */
     public abstract static class CombineScript {
         private final Map<String, Object> params;
         private final Map<String, Object> state;
@@ -188,6 +223,11 @@ public Map<String, Object> getState() {
 
         public abstract Object execute();
 
+        /**
+         * Factory for a scripted metric agg context
+         *
+         * @opensearch.internal
+         */
         public interface Factory extends ScriptFactory {
             CombineScript newInstance(Map<String, Object> params, Map<String, Object> state);
         }
@@ -196,6 +236,11 @@ public interface Factory extends ScriptFactory {
         public static ScriptContext<Factory> CONTEXT = new ScriptContext<>("aggs_combine", Factory.class);
     }
 
+    /**
+     * Base reduce script
+     *
+     * @opensearch.internal
+     */
     public abstract static class ReduceScript {
         private final Map<String, Object> params;
         private final List<Object> states;
@@ -215,6 +260,11 @@ public List<Object> getStates() {
 
         public abstract Object execute();
 
+        /**
+         * Factory for a scripted metric agg context
+         *
+         * @opensearch.internal
+         */
         public interface Factory extends ScriptFactory {
             ReduceScript newInstance(Map<String, Object> params, List<Object> states);
         }
diff --git a/server/src/main/java/org/opensearch/script/SearchScript.java b/server/src/main/java/org/opensearch/script/SearchScript.java
new file mode 100644
index 0000000000000..f40cc8ef080a4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/script/SearchScript.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.script;
+
+import org.opensearch.common.unit.TimeValue;
+
+import java.util.Map;
+
+/**
+ * A script used by the Search Script Processor.
+ *
+ * @opensearch.internal
+ */
+public abstract class SearchScript {
+
+    public static final String[] PARAMETERS = { "ctx" };
+
+    /** The context used to compile {@link SearchScript} factories. */
+    public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>(
+        "search",
+        Factory.class,
+        200,
+        TimeValue.timeValueMillis(0),
+        ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple()
+    );
+
+    /** The generic runtime parameters for the script. */
+    private final Map<String, Object> params;
+
+    public SearchScript(Map<String, Object> params) {
+        this.params = params;
+    }
+
+    /** Return the parameters for this script. */
+    public Map<String, Object> getParams() {
+        return params;
+    }
+
+    public abstract void execute(Map<String, Object> ctx);
+
+    /**
+     * Factory for search script
+     *
+     * @opensearch.internal
+     */
+    public interface Factory {
+        SearchScript newInstance(Map<String, Object> params);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/script/SignificantTermsHeuristicScoreScript.java b/server/src/main/java/org/opensearch/script/SignificantTermsHeuristicScoreScript.java
index 8227c673b9d97..3165dbc0641bb 100644
--- a/server/src/main/java/org/opensearch/script/SignificantTermsHeuristicScoreScript.java
+++ b/server/src/main/java/org/opensearch/script/SignificantTermsHeuristicScoreScript.java
@@ -36,6 +36,8 @@
 
 /**
  * A script used in significant terms heuristic scoring.
+ *
+ * @opensearch.internal
  */
 public abstract class SignificantTermsHeuristicScoreScript {
 
@@ -45,6 +47,11 @@ public abstract class SignificantTermsHeuristicScoreScript {
 
     public abstract double execute(Map<String, Object> params);
 
+    /**
+     * Factory for a significant terms heuristic score script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         SignificantTermsHeuristicScoreScript newInstance();
     }
diff --git a/server/src/main/java/org/opensearch/script/SimilarityScript.java b/server/src/main/java/org/opensearch/script/SimilarityScript.java
index 1683b8ad43bdf..9b0987598b0de 100644
--- a/server/src/main/java/org/opensearch/script/SimilarityScript.java
+++ b/server/src/main/java/org/opensearch/script/SimilarityScript.java
@@ -34,7 +34,11 @@
 
 import org.opensearch.index.similarity.ScriptedSimilarity;
 
-/** A script that is used to build {@link ScriptedSimilarity} instances. */
+/**
+ * A script that is used to build {@link ScriptedSimilarity} instances.
+ *
+ * @opensearch.internal
+ */
 public abstract class SimilarityScript {
 
     /** Compute the score.
@@ -52,6 +56,11 @@ public abstract double execute(
         ScriptedSimilarity.Doc doc
     );
 
+    /**
+     * Factory for a similarity script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         SimilarityScript newInstance();
     }
diff --git a/server/src/main/java/org/opensearch/script/SimilarityWeightScript.java b/server/src/main/java/org/opensearch/script/SimilarityWeightScript.java
index 33f2e76f24f2f..cb355728ae894 100644
--- a/server/src/main/java/org/opensearch/script/SimilarityWeightScript.java
+++ b/server/src/main/java/org/opensearch/script/SimilarityWeightScript.java
@@ -34,7 +34,11 @@
 
 import org.opensearch.index.similarity.ScriptedSimilarity;
 
-/** A script that is used to compute scoring factors that are the same for all documents. */
+/**
+ * A script that is used to compute scoring factors that are the same for all documents.
+ *
+ * @opensearch.internal
+ */
 public abstract class SimilarityWeightScript {
 
     /** Compute the weight.
@@ -44,6 +48,11 @@ public abstract class SimilarityWeightScript {
      */
     public abstract double execute(ScriptedSimilarity.Query query, ScriptedSimilarity.Field field, ScriptedSimilarity.Term term);
 
+    /**
+     * Factory for a similarity weight script
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         SimilarityWeightScript newInstance();
     }
diff --git a/server/src/main/java/org/opensearch/script/StoredScriptSource.java b/server/src/main/java/org/opensearch/script/StoredScriptSource.java
index a14d1db7259eb..0ff44b3af890a 100644
--- a/server/src/main/java/org/opensearch/script/StoredScriptSource.java
+++ b/server/src/main/java/org/opensearch/script/StoredScriptSource.java
@@ -35,24 +35,23 @@
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.Diff;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -65,6 +64,8 @@
 /**
  * {@link StoredScriptSource} represents user-defined parameters for a script
  * saved in the {@link ClusterState}.
+ *
+ * @opensearch.internal
  */
 public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> implements Writeable, ToXContentObject {
 
@@ -121,9 +122,9 @@ private void setSource(XContentParser parser) {
             try {
                 if (parser.currentToken() == Token.START_OBJECT) {
                     // this is really for search templates, that need to be converted to json format
-                    XContentBuilder builder = XContentFactory.jsonBuilder();
-                    source = Strings.toString(builder.copyCurrentStructure(parser));
-                    options.put(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType());
+                    XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
+                    source = builder.copyCurrentStructure(parser).toString();
+                    options.put(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType());
                 } else {
                     source = parser.text();
                 }
@@ -195,71 +196,72 @@ private StoredScriptSource build(boolean ignoreEmpty) {
 
     /**
      * This will parse XContent into a {@link StoredScriptSource}.  The following formats can be parsed:
-     *
+     * <p>
      * The simple script format with no compiler options or user-defined params:
-     *
+     * <p>
      * Example:
      * {@code
      * {"script": "return Math.log(doc.popularity) * 100;"}
      * }
-     *
+     * <p>
      * The above format requires the lang to be specified using the deprecated stored script namespace
      * (as a url parameter during a put request).  See {@link ScriptMetadata} for more information about
      * the stored script namespaces.
-     *
+     * <p>
      * The complex script format using the new stored script namespace
      * where lang and source are required but options is optional:
-     *
+     * <p>
      * {@code
      * {
-     *     "script" : {
-     *         "lang" : "<lang>",
-     *         "source" : "<source>",
-     *         "options" : {
-     *             "option0" : "<option0>",
-     *             "option1" : "<option1>",
-     *             ...
-     *         }
-     *     }
+     * "script" : {
+     * "lang" : "<lang>",
+     * "source" : "<source>",
+     * "options" : {
+     * "option0" : "<option0>",
+     * "option1" : "<option1>",
+     * ...
      * }
      * }
-     *
+     * }
+     * }
+     * <p>
      * Example:
      * {@code
      * {
-     *     "script": {
-     *         "lang" : "painless",
-     *         "source" : "return Math.log(doc.popularity) * params.multiplier"
-     *     }
+     * "script": {
+     * "lang" : "painless",
+     * "source" : "return Math.log(doc.popularity) * params.multiplier"
      * }
      * }
-     *
+     * }
+     * <p>
      * The use of "source" may also be substituted with "code" for backcompat with 5.3 to 5.5 format. For example:
-     *
+     * <p>
      * {@code
      * {
-     *     "script" : {
-     *         "lang" : "<lang>",
-     *         "code" : "<source>",
-     *         "options" : {
-     *             "option0" : "<option0>",
-     *             "option1" : "<option1>",
-     *             ...
-     *         }
-     *     }
+     * "script" : {
+     * "lang" : "<lang>",
+     * "code" : "<source>",
+     * "options" : {
+     * "option0" : "<option0>",
+     * "option1" : "<option1>",
+     * ...
      * }
      * }
-     *
+     * }
+     * }
+     * <p>
      * Note that the "source" parameter can also handle template parsing including from
      * a complex JSON object.
      *
-     * @param content The content from the request to be parsed as described above.
-     * @return        The parsed {@link StoredScriptSource}.
+     * @param content   The content from the request to be parsed as described above.
+     * @param mediaType The media type of the request
+     * @return The parsed {@link StoredScriptSource}.
      */
-    public static StoredScriptSource parse(BytesReference content, XContentType xContentType) {
+    public static StoredScriptSource parse(BytesReference content, MediaType mediaType) {
         try (
             InputStream stream = content.streamInput();
-            XContentParser parser = xContentType.xContent()
+            XContentParser parser = mediaType.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
         ) {
             Token token = parser.nextToken();
diff --git a/server/src/main/java/org/opensearch/script/StringSortScript.java b/server/src/main/java/org/opensearch/script/StringSortScript.java
index c518543588b3a..4491f318d841a 100644
--- a/server/src/main/java/org/opensearch/script/StringSortScript.java
+++ b/server/src/main/java/org/opensearch/script/StringSortScript.java
@@ -31,11 +31,17 @@
 
 package org.opensearch.script;
 
-import java.io.IOException;
-import java.util.Map;
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.search.lookup.SearchLookup;
 
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * Script for sorting strings
+ *
+ * @opensearch.internal
+ */
 public abstract class StringSortScript extends AbstractSortScript {
 
     public static final String[] PARAMETERS = {};
@@ -50,6 +56,8 @@ public StringSortScript(Map<String, Object> params, SearchLookup lookup, LeafRea
 
     /**
      * A factory to construct {@link StringSortScript} instances.
+     *
+     * @opensearch.internal
      */
     public interface LeafFactory {
         StringSortScript newInstance(LeafReaderContext ctx) throws IOException;
@@ -57,6 +65,8 @@ public interface LeafFactory {
 
     /**
      * A factory to construct stateful {@link StringSortScript} factories for a specific index.
+     *
+     * @opensearch.internal
      */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
diff --git a/server/src/main/java/org/opensearch/script/TemplateScript.java b/server/src/main/java/org/opensearch/script/TemplateScript.java
index 2e13599af044c..769999baba98d 100644
--- a/server/src/main/java/org/opensearch/script/TemplateScript.java
+++ b/server/src/main/java/org/opensearch/script/TemplateScript.java
@@ -36,6 +36,8 @@
 
 /**
  * A string template rendered as a script.
+ *
+ * @opensearch.internal
  */
 public abstract class TemplateScript {
 
@@ -55,6 +57,11 @@ public Map<String, Object> getParams() {
     /** Run a template and return the resulting string, encoded in utf8 bytes. */
     public abstract String execute();
 
+    /**
+     * Factory for a template script
+     *
+     * @opensearch.internal
+     */
     public interface Factory {
         TemplateScript newInstance(Map<String, Object> params);
     }
diff --git a/server/src/main/java/org/opensearch/script/TermsSetQueryScript.java b/server/src/main/java/org/opensearch/script/TermsSetQueryScript.java
index 200779cab2de0..99fa2d584ebfd 100644
--- a/server/src/main/java/org/opensearch/script/TermsSetQueryScript.java
+++ b/server/src/main/java/org/opensearch/script/TermsSetQueryScript.java
@@ -43,6 +43,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Script for terms set query
+ *
+ * @opensearch.internal
+ */
 public abstract class TermsSetQueryScript {
 
     public static final String[] PARAMETERS = {};
@@ -50,7 +55,7 @@ public abstract class TermsSetQueryScript {
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("terms_set", Factory.class);
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("doc", value -> {
+    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = Map.of("doc", value -> {
         deprecationLogger.deprecate(
             "terms-set-query-script_doc",
             "Accessing variable [doc] via [params.doc] from within an terms-set-query-script "
@@ -120,6 +125,8 @@ public long runAsLong() {
 
     /**
      * A factory to construct {@link TermsSetQueryScript} instances.
+     *
+     * @opensearch.internal
      */
     public interface LeafFactory {
         TermsSetQueryScript newInstance(LeafReaderContext ctx) throws IOException;
@@ -127,6 +134,8 @@ public interface LeafFactory {
 
     /**
      * A factory to construct stateful {@link TermsSetQueryScript} factories for a specific index.
+     *
+     * @opensearch.internal
      */
     public interface Factory extends ScriptFactory {
         LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup);
diff --git a/server/src/main/java/org/opensearch/script/UpdateScript.java b/server/src/main/java/org/opensearch/script/UpdateScript.java
index aef8049bbeb0b..86697e9ae550e 100644
--- a/server/src/main/java/org/opensearch/script/UpdateScript.java
+++ b/server/src/main/java/org/opensearch/script/UpdateScript.java
@@ -32,22 +32,15 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.logging.DeprecationLogger;
-
 import java.util.Map;
-import java.util.function.Function;
 
 /**
  * An update script.
+ *
+ * @opensearch.internal
  */
 public abstract class UpdateScript {
 
-    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(DynamicMap.class);
-    private static final Map<String, Function<Object, Object>> PARAMS_FUNCTIONS = org.opensearch.common.collect.Map.of("_type", value -> {
-        deprecationLogger.deprecate("update-script", "[types removal] Looking up doc types [_type] in scripts is deprecated.");
-        return value;
-    });
-
     public static final String[] PARAMETERS = {};
 
     /** The context used to compile {@link UpdateScript} factories. */
@@ -61,7 +54,7 @@ public abstract class UpdateScript {
 
     public UpdateScript(Map<String, Object> params, Map<String, Object> ctx) {
         this.params = params;
-        this.ctx = new DynamicMap(ctx, PARAMS_FUNCTIONS);
+        this.ctx = ctx;
     }
 
     /** Return the parameters for this script. */
@@ -76,6 +69,11 @@ public Map<String, Object> getCtx() {
 
     public abstract void execute();
 
+    /**
+     * Factory for an update script
+     *
+     * @opensearch.internal
+     */
     public interface Factory {
         UpdateScript newInstance(Map<String, Object> params, Map<String, Object> ctx);
     }
diff --git a/server/src/main/java/org/opensearch/search/DefaultSearchContext.java b/server/src/main/java/org/opensearch/search/DefaultSearchContext.java
index bfe8eed05ea9b..59108b70a09af 100644
--- a/server/src/main/java/org/opensearch/search/DefaultSearchContext.java
+++ b/server/src/main/java/org/opensearch/search/DefaultSearchContext.java
@@ -36,6 +36,7 @@
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
@@ -44,10 +45,13 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
@@ -62,7 +66,10 @@
 import org.opensearch.index.search.NestedHelper;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.similarity.SimilarityService;
+import org.opensearch.search.aggregations.BucketCollectorProcessor;
+import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.SearchContextAggregations;
+import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.collapse.CollapseContext;
 import org.opensearch.search.dfs.DfsSearchResult;
 import org.opensearch.search.fetch.FetchPhase;
@@ -74,6 +81,7 @@
 import org.opensearch.search.fetch.subphase.ScriptFieldsContext;
 import org.opensearch.search.fetch.subphase.highlight.SearchHighlightContext;
 import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.PitReaderContext;
 import org.opensearch.search.internal.ReaderContext;
 import org.opensearch.search.internal.ScrollContext;
 import org.opensearch.search.internal.SearchContext;
@@ -82,6 +90,7 @@
 import org.opensearch.search.profile.Profilers;
 import org.opensearch.search.query.QueryPhaseExecutionException;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.query.ReduceableSearchResult;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.slice.SliceBuilder;
 import org.opensearch.search.sort.SortAndFormats;
@@ -95,8 +104,16 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Executor;
+import java.util.function.Function;
 import java.util.function.LongSupplier;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
+
+/**
+ * The main search context used during search phase
+ *
+ * @opensearch.internal
+ */
 final class DefaultSearchContext extends SearchContext {
 
     private final ReaderContext readerContext;
@@ -161,11 +178,14 @@ final class DefaultSearchContext extends SearchContext {
     private SuggestionSearchContext suggest;
     private List<RescoreContext> rescore;
     private Profilers profilers;
-
+    private BucketCollectorProcessor bucketCollectorProcessor = NO_OP_BUCKET_COLLECTOR_PROCESSOR;
     private final Map<String, SearchExtBuilder> searchExtBuilders = new HashMap<>();
-    private final Map<Class<?>, Collector> queryCollectors = new HashMap<>();
+    private final Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers = new HashMap<>();
     private final QueryShardContext queryShardContext;
     private final FetchPhase fetchPhase;
+    private final Function<SearchSourceBuilder, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder;
+    private final boolean concurrentSearchSettingsEnabled;
+    private final SetOnce<Boolean> requestShouldUseConcurrentSearch = new SetOnce<>();
 
     DefaultSearchContext(
         ReaderContext readerContext,
@@ -179,7 +199,8 @@ final class DefaultSearchContext extends SearchContext {
         boolean lowLevelCancellation,
         Version minNodeVersion,
         boolean validate,
-        Executor executor
+        Executor executor,
+        Function<SearchSourceBuilder, InternalAggregation.ReduceContextBuilder> requestToAggReduceContextBuilder
     ) throws IOException {
         this.readerContext = readerContext;
         this.request = request;
@@ -195,13 +216,15 @@ final class DefaultSearchContext extends SearchContext {
         this.indexShard = readerContext.indexShard();
         this.clusterService = clusterService;
         this.engineSearcher = readerContext.acquireSearcher("search");
+        this.concurrentSearchSettingsEnabled = evaluateConcurrentSegmentSearchSettings(executor);
         this.searcher = new ContextIndexSearcher(
             engineSearcher.getIndexReader(),
             engineSearcher.getSimilarity(),
             engineSearcher.getQueryCache(),
             engineSearcher.getQueryCachingPolicy(),
             lowLevelCancellation,
-            executor
+            concurrentSearchSettingsEnabled ? executor : null,
+            this
         );
         this.relativeTimeSupplier = relativeTimeSupplier;
         this.timeout = timeout;
@@ -215,6 +238,7 @@ final class DefaultSearchContext extends SearchContext {
         );
         queryBoost = request.indexBoost();
         this.lowLevelCancellation = lowLevelCancellation;
+        this.requestToAggReduceContextBuilder = requestToAggReduceContextBuilder;
     }
 
     @Override
@@ -280,7 +304,7 @@ public void preProcess(boolean rewrite) {
             }
         }
 
-        if (sliceBuilder != null) {
+        if (sliceBuilder != null && scrollContext() != null) {
             int sliceLimit = indexService.getIndexSettings().getMaxSlicesPerScroll();
             int numSlices = sliceBuilder.getMax();
             if (numSlices > sliceLimit) {
@@ -297,6 +321,22 @@ public void preProcess(boolean rewrite) {
             }
         }
 
+        if (sliceBuilder != null && readerContext != null && readerContext instanceof PitReaderContext) {
+            int sliceLimit = indexService.getIndexSettings().getMaxSlicesPerPit();
+            int numSlices = sliceBuilder.getMax();
+            if (numSlices > sliceLimit) {
+                throw new OpenSearchRejectedExecutionException(
+                    "The number of slices ["
+                        + numSlices
+                        + "] is too large. It must "
+                        + "be less than ["
+                        + sliceLimit
+                        + "]. This limit can be set by changing the ["
+                        + IndexSettings.MAX_SLICES_PER_PIT.getKey()
+                        + "] index level setting."
+                );
+            }
+        }
         // initialize the filtering alias based on the provided filters
         try {
             final QueryBuilder queryBuilder = request.getAliasFilter().getQueryBuilder();
@@ -823,8 +863,8 @@ public long getRelativeTimeInMillis() {
     }
 
     @Override
-    public Map<Class<?>, Collector> queryCollectors() {
-        return queryCollectors;
+    public Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers() {
+        return queryCollectorManagers;
     }
 
     @Override
@@ -837,6 +877,32 @@ public Profilers getProfilers() {
         return profilers;
     }
 
+    /**
+     * Returns concurrent segment search status for the search context. This should only be used after request parsing, during which requestShouldUseConcurrentSearch will be set.
+     */
+    @Override
+    public boolean shouldUseConcurrentSearch() {
+        assert requestShouldUseConcurrentSearch.get() != null : "requestShouldUseConcurrentSearch must be set";
+        return concurrentSearchSettingsEnabled && Boolean.TRUE.equals(requestShouldUseConcurrentSearch.get());
+    }
+
+    /**
+     * Evaluate if parsed request supports concurrent segment search
+     */
+    public void evaluateRequestShouldUseConcurrentSearch() {
+        if (sort != null && sort.isSortOnTimeSeriesField()) {
+            requestShouldUseConcurrentSearch.set(false);
+        } else if (aggregations() != null
+            && aggregations().factories() != null
+            && !aggregations().factories().allFactoriesSupportConcurrentSearch()) {
+                requestShouldUseConcurrentSearch.set(false);
+            } else if (terminateAfter != DEFAULT_TERMINATE_AFTER) {
+                requestShouldUseConcurrentSearch.set(false);
+            } else {
+                requestShouldUseConcurrentSearch.set(true);
+            }
+    }
+
     public void setProfilers(Profilers profilers) {
         this.profilers = profilers;
     }
@@ -860,4 +926,49 @@ public boolean isCancelled() {
     public ReaderContext readerContext() {
         return readerContext;
     }
+
+    @Override
+    public InternalAggregation.ReduceContext partialOnShard() {
+        InternalAggregation.ReduceContext rc = requestToAggReduceContextBuilder.apply(request.source()).forPartialReduction();
+        rc.setSliceLevel(shouldUseConcurrentSearch());
+        return rc;
+    }
+
+    @Override
+    public void setBucketCollectorProcessor(BucketCollectorProcessor bucketCollectorProcessor) {
+        this.bucketCollectorProcessor = bucketCollectorProcessor;
+    }
+
+    @Override
+    public BucketCollectorProcessor bucketCollectorProcessor() {
+        return bucketCollectorProcessor;
+    }
+
+    /**
+     * Evaluate based on cluster and index settings if concurrent segment search should be used for this request context
+     * @return true: use concurrent search
+     *         false: otherwise
+     */
+    private boolean evaluateConcurrentSegmentSearchSettings(Executor concurrentSearchExecutor) {
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)
+            && (clusterService != null)
+            && (concurrentSearchExecutor != null)) {
+            return indexService.getIndexSettings()
+                .getSettings()
+                .getAsBoolean(
+                    IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(),
+                    clusterService.getClusterSettings().get(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING)
+                );
+        } else {
+            return false;
+        }
+    }
+
+    @Override
+    public boolean shouldUseTimeSeriesDescSortOptimization() {
+        return indexShard.isTimeSeriesDescSortOptimizationEnabled()
+            && sort != null
+            && sort.isSortOnTimeSeriesField()
+            && sort.sort.getSort()[0].getReverse() == false;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/DocValueFormat.java b/server/src/main/java/org/opensearch/search/DocValueFormat.java
index 9536e72c04b7b..febb270ea917c 100644
--- a/server/src/main/java/org/opensearch/search/DocValueFormat.java
+++ b/server/src/main/java/org/opensearch/search/DocValueFormat.java
@@ -35,9 +35,7 @@
 import org.apache.lucene.document.InetAddressPoint;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.joda.Joda;
 import org.opensearch.common.joda.JodaDateFormatter;
 import org.opensearch.common.network.InetAddresses;
@@ -45,9 +43,12 @@
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.time.DateUtils;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.index.mapper.DateFieldMapper;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 
 import java.io.IOException;
 import java.math.BigInteger;
@@ -63,7 +64,11 @@
 import java.util.Objects;
 import java.util.function.LongSupplier;
 
-/** A formatter for values as returned by the fielddata/doc-values APIs. */
+/**
+ * A formatter for values as returned by the fielddata/doc-values APIs.
+ *
+ * @opensearch.internal
+ */
 public interface DocValueFormat extends NamedWriteable {
     long MASK_2_63 = 0x8000000000000000L;
     BigInteger BIGINTEGER_2_64_MINUS_ONE = BigInteger.ONE.shiftLeft(64).subtract(BigInteger.ONE); // 2^64 -1
@@ -82,6 +87,13 @@ default Object format(double value) {
         throw new UnsupportedOperationException();
     }
 
+    /** Format a unsigned long value. This is used by terms and histogram aggregations
+     *  to format keys for fields that use unsigned longs as a doc value representation
+     *  such as the {@code unsigned_long} field. */
+    default BigInteger format(BigInteger value) {
+        throw new UnsupportedOperationException();
+    }
+
     /** Format a binary value. This is used by terms aggregations to format
      *  keys for fields that use binary doc value representations such as the
      *  {@code keyword} and {@code ip} fields. */
@@ -95,6 +107,12 @@ default long parseLong(String value, boolean roundUp, LongSupplier now) {
         throw new UnsupportedOperationException();
     }
 
+    /** Parse a value that was formatted with {@link #format(long)} back to the
+     *  original unsigned long value. */
+    default BigInteger parseUnsignedLong(String value, boolean roundUp, LongSupplier now) {
+        throw new UnsupportedOperationException();
+    }
+
     /** Parse a value that was formatted with {@link #format(double)} back to
      *  the original double value. */
     default double parseDouble(String value, boolean roundUp, LongSupplier now) {
@@ -127,6 +145,15 @@ public Double format(double value) {
             return value;
         }
 
+        /**
+         * Double docValues of the unsigned_long field type are already in the formatted representation,
+         * so we don't need to do anything here
+         */
+        @Override
+        public BigInteger format(BigInteger value) {
+            return value;
+        }
+
         @Override
         public String format(BytesRef value) {
             return value.utf8ToString();
@@ -197,6 +224,11 @@ static DocValueFormat withNanosecondResolution(final DocValueFormat format) {
         }
     }
 
+    /**
+     * Date time doc value format
+     *
+     * @opensearch.internal
+     */
     final class DateTime implements DocValueFormat {
 
         public static final String NAME = "date_time";
@@ -293,6 +325,27 @@ public double parseDouble(String value, boolean roundUp, LongSupplier now) {
         public String toString() {
             return "DocValueFormat.DateTime(" + formatter + ", " + timeZone + ", " + resolution + ")";
         }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            DateTime that = (DateTime) o;
+
+            return Objects.equals(formatter, that.formatter)
+                && Objects.equals(timeZone, that.timeZone)
+                && Objects.equals(resolution, that.resolution);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(formatter, timeZone, resolution);
+        }
     }
 
     DocValueFormat GEOHASH = new DocValueFormat() {
@@ -402,6 +455,11 @@ public String toString() {
         }
     };
 
+    /**
+     * Decimal doc value format
+     *
+     * @opensearch.internal
+     */
     final class Decimal implements DocValueFormat {
 
         public static final String NAME = "decimal";
@@ -434,6 +492,15 @@ public String format(long value) {
             return format.format(value);
         }
 
+        /**
+         * Double docValues of the unsigned_long field type are already in the formatted representation,
+         * so we don't need to do anything here
+         */
+        @Override
+        public BigInteger format(BigInteger value) {
+            return value;
+        }
+
         @Override
         public String format(double value) {
             /*
@@ -535,6 +602,14 @@ public long parseLong(String value, boolean roundUp, LongSupplier now) {
             return parsedValue ^ MASK_2_63;
         }
 
+        /**
+         * Formats the unsigned long to the shifted long format
+         */
+        @Override
+        public BigInteger parseUnsignedLong(String value, boolean roundUp, LongSupplier now) {
+            return Numbers.toUnsignedLong(value, roundUp);
+        }
+
         /**
          * Formats a raw docValue that is stored in the shifted long format to the unsigned long representation.
          */
@@ -564,4 +639,71 @@ public double parseDouble(String value, boolean roundUp, LongSupplier now) {
             return Double.parseDouble(value);
         }
     };
+
+    /**
+     * DocValues format for unsigned 64 bit long values,
+     * that are stored as signed 64 bit long values.
+     */
+    DocValueFormat UNSIGNED_LONG = new DocValueFormat() {
+
+        @Override
+        public String getWriteableName() {
+            return "unsigned_long";
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) {}
+
+        @Override
+        public String toString() {
+            return "unsigned_long";
+        }
+
+        /**
+         * Formats the unsigned long to the shifted long format
+         */
+        @Override
+        public long parseLong(String value, boolean roundUp, LongSupplier now) {
+            return Long.parseUnsignedLong(value);
+        }
+
+        /**
+         * Formats the unsigned long to the shifted long format
+         */
+        @Override
+        public BigInteger parseUnsignedLong(String value, boolean roundUp, LongSupplier now) {
+            return Numbers.toUnsignedLong(value, roundUp);
+        }
+
+        /**
+         * Formats a raw docValue that is stored in the shifted long format to the unsigned long representation.
+         */
+        @Override
+        public Object format(long value) {
+            return Numbers.toUnsignedBigInteger(value);
+        }
+
+        /**
+         * Double docValues of the unsigned_long field type are already in the formatted representation,
+         * so we don't need to do anything here
+         */
+        @Override
+        public BigInteger format(BigInteger value) {
+            return value;
+        }
+
+        /**
+         * Double docValues of the unsigned_long field type are already in the formatted representation,
+         * so we don't need to do anything here
+         */
+        @Override
+        public Double format(double value) {
+            return value;
+        }
+
+        @Override
+        public double parseDouble(String value, boolean roundUp, LongSupplier now) {
+            return Double.parseDouble(value);
+        }
+    };
 }
diff --git a/server/src/main/java/org/opensearch/search/GenericSearchExtBuilder.java b/server/src/main/java/org/opensearch/search/GenericSearchExtBuilder.java
new file mode 100644
index 0000000000000..35e68f78774e3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/GenericSearchExtBuilder.java
@@ -0,0 +1,165 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.search;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * This is a catch-all SearchExtBuilder implementation that is used when an appropriate SearchExtBuilder
+ * is not found during SearchResponse's fromXContent operation.
+ */
+public final class GenericSearchExtBuilder extends SearchExtBuilder {
+
+    public final static ParseField EXT_BUILDER_NAME = new ParseField("generic_ext");
+
+    private final Object genericObj;
+    private final ValueType valueType;
+
+    enum ValueType {
+        SIMPLE(0),
+        MAP(1),
+        LIST(2);
+
+        private final int value;
+
+        ValueType(int value) {
+            this.value = value;
+        }
+
+        public int getValue() {
+            return value;
+        }
+
+        static ValueType fromInt(int value) {
+            switch (value) {
+                case 0:
+                    return SIMPLE;
+                case 1:
+                    return MAP;
+                case 2:
+                    return LIST;
+                default:
+                    throw new IllegalArgumentException("Unsupported value: " + value);
+            }
+        }
+    }
+
+    public GenericSearchExtBuilder(Object genericObj, ValueType valueType) {
+        this.genericObj = genericObj;
+        this.valueType = valueType;
+    }
+
+    public GenericSearchExtBuilder(StreamInput in) throws IOException {
+        valueType = ValueType.fromInt(in.readInt());
+        switch (valueType) {
+            case SIMPLE:
+                genericObj = in.readGenericValue();
+                break;
+            case MAP:
+                genericObj = in.readMap();
+                break;
+            case LIST:
+                genericObj = in.readList(r -> r.readGenericValue());
+                break;
+            default:
+                throw new IllegalStateException("Unable to construct GenericSearchExtBuilder from incoming stream.");
+        }
+    }
+
+    public static GenericSearchExtBuilder fromXContent(XContentParser parser) throws IOException {
+        // Look at the parser's next token.
+        // If it's START_OBJECT, parse as map, if it's START_ARRAY, parse as list, else
+        // parse as simpleVal
+        XContentParser.Token token = parser.currentToken();
+        ValueType valueType;
+        Object genericObj;
+        if (token == XContentParser.Token.START_OBJECT) {
+            genericObj = parser.map();
+            valueType = ValueType.MAP;
+        } else if (token == XContentParser.Token.START_ARRAY) {
+            genericObj = parser.list();
+            valueType = ValueType.LIST;
+        } else if (token.isValue()) {
+            genericObj = parser.objectText();
+            valueType = ValueType.SIMPLE;
+        } else {
+            throw new XContentParseException("Unknown token: " + token);
+        }
+
+        return new GenericSearchExtBuilder(genericObj, valueType);
+    }
+
+    @Override
+    public String getWriteableName() {
+        return EXT_BUILDER_NAME.getPreferredName();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeInt(valueType.getValue());
+        switch (valueType) {
+            case SIMPLE:
+                out.writeGenericValue(genericObj);
+                break;
+            case MAP:
+                out.writeMap((Map<String, Object>) genericObj);
+                break;
+            case LIST:
+                out.writeCollection((List<Object>) genericObj, StreamOutput::writeGenericValue);
+                break;
+            default:
+                throw new IllegalStateException("Unknown valueType: " + valueType);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        switch (valueType) {
+            case SIMPLE:
+                return builder.field(EXT_BUILDER_NAME.getPreferredName(), genericObj);
+            case MAP:
+                return builder.field(EXT_BUILDER_NAME.getPreferredName(), (Map<String, Object>) genericObj);
+            case LIST:
+                return builder.field(EXT_BUILDER_NAME.getPreferredName(), (List<Object>) genericObj);
+            default:
+                return null;
+        }
+    }
+
+    // We need this for the equals method.
+    Object getValue() {
+        return genericObj;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.valueType, this.genericObj);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof GenericSearchExtBuilder)) {
+            return false;
+        }
+        return Objects.equals(getValue(), ((GenericSearchExtBuilder) obj).getValue())
+            && Objects.equals(valueType, ((GenericSearchExtBuilder) obj).valueType);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/MultiValueMode.java b/server/src/main/java/org/opensearch/search/MultiValueMode.java
index bc09d972054a5..0fbd41f062710 100644
--- a/server/src/main/java/org/opensearch/search/MultiValueMode.java
+++ b/server/src/main/java/org/opensearch/search/MultiValueMode.java
@@ -42,9 +42,9 @@
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.fielddata.AbstractBinaryDocValues;
 import org.opensearch.index.fielddata.AbstractNumericDocValues;
 import org.opensearch.index.fielddata.AbstractSortedDocValues;
@@ -58,6 +58,8 @@
 
 /**
  * Defines what values to pick in the case a document contains multiple values for a particular field.
+ *
+ * @opensearch.internal
  */
 public enum MultiValueMode implements Writeable {
     /**
diff --git a/server/src/main/java/org/opensearch/search/RescoreDocIds.java b/server/src/main/java/org/opensearch/search/RescoreDocIds.java
index bf19d25975393..880f34a924f2a 100644
--- a/server/src/main/java/org/opensearch/search/RescoreDocIds.java
+++ b/server/src/main/java/org/opensearch/search/RescoreDocIds.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -45,6 +45,8 @@
  * Since {@link org.opensearch.search.internal.SearchContext} no longer hold the states of search, the top K results
  * (i.e., documents that will be rescored by query rescorers) need to be serialized/ deserialized between search phases.
  * A {@link RescoreDocIds} encapsulates the top K results for each rescorer by its ordinal index.
+ *
+ * @opensearch.internal
  */
 public final class RescoreDocIds implements Writeable {
     public static final RescoreDocIds EMPTY = new RescoreDocIds(Collections.emptyMap());
diff --git a/server/src/main/java/org/opensearch/search/Scroll.java b/server/src/main/java/org/opensearch/search/Scroll.java
index f46078ae82d26..8003316a57e5e 100644
--- a/server/src/main/java/org/opensearch/search/Scroll.java
+++ b/server/src/main/java/org/opensearch/search/Scroll.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -44,7 +44,7 @@
  * A scroll enables scrolling of search request. It holds a {@link #keepAlive()} time that
  * will control how long to keep the scrolling resources open.
  *
- *
+ * @opensearch.internal
  */
 public final class Scroll implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/search/SearchBootstrapSettings.java b/server/src/main/java/org/opensearch/search/SearchBootstrapSettings.java
new file mode 100644
index 0000000000000..7d167838a77c3
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/SearchBootstrapSettings.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search;
+
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+
+/**
+ * Keeps track of all the search related node level settings which can be accessed via static methods
+ *
+ * @opensearch.internal
+ */
+public class SearchBootstrapSettings {
+    // settings to configure maximum slice created per search request using OS custom slice computation mechanism. Default lucene
+    // mechanism will not be used if this setting is set with value > 0
+    public static final String CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY = "search.concurrent.max_slice_count";
+    public static final int CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE = 0;
+
+    // value == 0 means lucene slice computation will be used
+    // this setting will be updated to dynamic setting as part of https://github.com/opensearch-project/OpenSearch/issues/8870
+    public static final Setting<Integer> CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING = Setting.intSetting(
+        CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY,
+        CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE,
+        CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE,
+        Setting.Property.NodeScope
+    );
+    private static Settings settings;
+
+    public static void initialize(Settings openSearchSettings) {
+        settings = openSearchSettings;
+    }
+
+    public static int getTargetMaxSlice() {
+        return (settings != null)
+            ? settings.getAsInt(
+                CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY,
+                CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE
+            )
+            : CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/SearchContextMissingException.java b/server/src/main/java/org/opensearch/search/SearchContextMissingException.java
index 1e96077a6730e..93bbe7e9ce64f 100644
--- a/server/src/main/java/org/opensearch/search/SearchContextMissingException.java
+++ b/server/src/main/java/org/opensearch/search/SearchContextMissingException.java
@@ -33,13 +33,18 @@
 package org.opensearch.search;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.search.internal.ShardSearchContextId;
 
 import java.io.IOException;
 
+/**
+ * Error thrown if no search context is available
+ *
+ * @opensearch.internal
+ */
 public class SearchContextMissingException extends OpenSearchException {
 
     private final ShardSearchContextId contextId;
diff --git a/server/src/main/java/org/opensearch/search/SearchContextSourcePrinter.java b/server/src/main/java/org/opensearch/search/SearchContextSourcePrinter.java
index 8f226ab86378f..c673eb512347c 100644
--- a/server/src/main/java/org/opensearch/search/SearchContextSourcePrinter.java
+++ b/server/src/main/java/org/opensearch/search/SearchContextSourcePrinter.java
@@ -35,6 +35,11 @@
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.tasks.Task;
 
+/**
+ * Prints the search context source
+ *
+ * @opensearch.internal
+ */
 public class SearchContextSourcePrinter {
     private final SearchContext searchContext;
 
diff --git a/server/src/main/java/org/opensearch/search/SearchException.java b/server/src/main/java/org/opensearch/search/SearchException.java
index afe99cb62a67b..657e39d663513 100644
--- a/server/src/main/java/org/opensearch/search/SearchException.java
+++ b/server/src/main/java/org/opensearch/search/SearchException.java
@@ -34,11 +34,16 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Error thrown if there is a problem during search
+ *
+ * @opensearch.internal
+ */
 public class SearchException extends OpenSearchException implements OpenSearchWrapperException {
 
     private final SearchShardTarget shardTarget;
diff --git a/server/src/main/java/org/opensearch/search/SearchExtBuilder.java b/server/src/main/java/org/opensearch/search/SearchExtBuilder.java
index ad1c4b47f1ac1..4d86c6c2e2277 100644
--- a/server/src/main/java/org/opensearch/search/SearchExtBuilder.java
+++ b/server/src/main/java/org/opensearch/search/SearchExtBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.search;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.plugins.SearchPlugin.SearchExtSpec;
 
@@ -55,6 +55,8 @@
  * of the {@link SearchExtSpec}.
  *
  * @see SearchExtSpec
+ *
+ * @opensearch.internal
  */
 public abstract class SearchExtBuilder implements NamedWriteable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/SearchHit.java b/server/src/main/java/org/opensearch/search/SearchHit.java
index daae83e408530..fab9c1b773d0b 100644
--- a/server/src/main/java/org/opensearch/search/SearchHit.java
+++ b/server/src/main/java/org/opensearch/search/SearchHit.java
@@ -38,30 +38,32 @@
 import org.opensearch.Version;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.SourceFieldMapper;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.fetch.subphase.highlight.HighlightField;
 import org.opensearch.search.lookup.SourceLookup;
 import org.opensearch.transport.RemoteClusterAware;
@@ -81,15 +83,17 @@
 import static java.util.Collections.unmodifiableMap;
 import static org.opensearch.common.lucene.Lucene.readExplanation;
 import static org.opensearch.common.lucene.Lucene.writeExplanation;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureFieldName;
 
 /**
  * A single search hit.
  *
  * @see SearchHits
+ *
+ * @opensearch.internal
  */
 public final class SearchHit implements Writeable, ToXContentObject, Iterable<DocumentField> {
 
@@ -396,7 +400,7 @@ public BytesReference getSourceRef() {
         }
 
         try {
-            this.source = CompressorFactory.uncompressIfNeeded(this.source);
+            this.source = CompressorRegistry.uncompressIfNeeded(this.source);
             return this.source;
         } catch (IOException e) {
             throw new OpenSearchParseException("failed to decompress source", e);
@@ -477,6 +481,10 @@ public void setDocumentField(String fieldName, DocumentField field) {
         this.documentFields.put(fieldName, field);
     }
 
+    public DocumentField removeDocumentField(String fieldName) {
+        return documentFields.remove(fieldName);
+    }
+
     /**
      * A map of hit fields (from field name to hit fields) if additional fields
      * were required to be loaded.
@@ -588,6 +596,11 @@ public void setInnerHits(Map<String, SearchHits> innerHits) {
         this.innerHits = innerHits;
     }
 
+    /**
+     * Fields in a search hit used for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     public static class Fields {
         static final String _INDEX = "_index";
         static final String _ID = "_id";
@@ -732,7 +745,7 @@ public XContentBuilder toInnerXContent(XContentBuilder builder, Params params) t
      * is that this way we can reuse the parser when parsing xContent from
      * {@link org.opensearch.search.suggest.completion.CompletionSuggestion.Entry.Option} which unfortunately inlines
      * the output of
-     * {@link #toInnerXContent(XContentBuilder, org.opensearch.common.xcontent.ToXContent.Params)}
+     * {@link #toInnerXContent(XContentBuilder, ToXContent.Params)}
      * of the included search hit. The output of the map is used to create the
      * actual SearchHit instance via {@link #createFromMap(Map)}
      */
@@ -998,6 +1011,8 @@ public int hashCode() {
 
     /**
      * Encapsulates the nested identity of a hit.
+     *
+     * @opensearch.internal
      */
     public static final class NestedIdentity implements Writeable, ToXContentFragment {
 
@@ -1115,6 +1130,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/SearchHits.java b/server/src/main/java/org/opensearch/search/SearchHits.java
index 8abbaa6c9e6c2..1d497840bd12b 100644
--- a/server/src/main/java/org/opensearch/search/SearchHits.java
+++ b/server/src/main/java/org/opensearch/search/SearchHits.java
@@ -36,13 +36,13 @@
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.TotalHits.Relation;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.search.RestSearchAction;
 
 import java.io.IOException;
@@ -52,8 +52,13 @@
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Encapsulates the results of a search operation
+ *
+ * @opensearch.internal
+ */
 public final class SearchHits implements Writeable, ToXContentFragment, Iterable<SearchHit> {
     public static SearchHits empty() {
         return empty(true);
@@ -196,6 +201,11 @@ public Iterator<SearchHit> iterator() {
         return Arrays.stream(getHits()).iterator();
     }
 
+    /**
+     * Fields for parsing and toXContent
+     *
+     * @opensearch.internal
+     */
     public static final class Fields {
         public static final String HITS = "hits";
         public static final String TOTAL = "total";
diff --git a/server/src/main/java/org/opensearch/search/SearchModule.java b/server/src/main/java/org/opensearch/search/SearchModule.java
index dc5309b50abb8..65b4ba3f94987 100644
--- a/server/src/main/java/org/opensearch/search/SearchModule.java
+++ b/server/src/main/java/org/opensearch/search/SearchModule.java
@@ -35,17 +35,18 @@
 import org.apache.lucene.search.BooleanQuery;
 import org.opensearch.common.NamedRegistry;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.ShapesAvailability;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.ParseFieldRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.BoostingQueryBuilder;
 import org.opensearch.index.query.CommonTermsQueryBuilder;
@@ -126,10 +127,6 @@
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilter;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilters;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.InternalGeoHashGrid;
-import org.opensearch.search.aggregations.bucket.geogrid.InternalGeoTileGrid;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.global.InternalGlobal;
 import org.opensearch.search.aggregations.bucket.histogram.AutoDateHistogramAggregationBuilder;
@@ -159,8 +156,11 @@
 import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.sampler.UnmappedSampler;
 import org.opensearch.search.aggregations.bucket.terms.DoubleTerms;
+import org.opensearch.search.aggregations.bucket.terms.InternalMultiTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongTerms;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationFactory;
 import org.opensearch.search.aggregations.bucket.terms.RareTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.SignificantLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantStringTerms;
@@ -172,6 +172,7 @@
 import org.opensearch.search.aggregations.bucket.terms.UnmappedRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.UnmappedSignificantTerms;
 import org.opensearch.search.aggregations.bucket.terms.UnmappedTerms;
+import org.opensearch.search.aggregations.bucket.terms.UnsignedLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.ChiSquare;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.GND;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.JLHScore;
@@ -182,12 +183,10 @@
 import org.opensearch.search.aggregations.metrics.AvgAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.CardinalityAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.ExtendedStatsAggregationBuilder;
-import org.opensearch.search.aggregations.metrics.GeoBoundsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.GeoCentroidAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.InternalAvg;
 import org.opensearch.search.aggregations.metrics.InternalCardinality;
 import org.opensearch.search.aggregations.metrics.InternalExtendedStats;
-import org.opensearch.search.aggregations.metrics.InternalGeoBounds;
 import org.opensearch.search.aggregations.metrics.InternalGeoCentroid;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentiles;
@@ -276,6 +275,7 @@
 import org.opensearch.search.fetch.subphase.highlight.UnifiedHighlighter;
 import org.opensearch.search.query.QueryPhase;
 import org.opensearch.search.query.QueryPhaseSearcher;
+import org.opensearch.search.query.QueryPhaseSearcherWrapper;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.search.rescore.RescorerBuilder;
 import org.opensearch.search.sort.FieldSortBuilder;
@@ -311,9 +311,12 @@
 import static java.util.Collections.unmodifiableMap;
 import static java.util.Objects.requireNonNull;
 import static org.opensearch.index.query.CommonTermsQueryBuilder.COMMON_TERMS_QUERY_DEPRECATION_MSG;
+import static org.opensearch.threadpool.ThreadPool.Names.INDEX_SEARCHER;
 
 /**
  * Sets up things that can be done at search time like queries, aggregations, and suggesters.
+ *
+ * @opensearch.internal
  */
 public class SearchModule {
     public static final Setting<Integer> INDICES_MAX_CLAUSE_COUNT_SETTING = Setting.intSetting(
@@ -537,6 +540,7 @@ private ValuesSourceRegistry registerAggregations(List<SearchPlugin> plugins) {
                 .addResultReader(UnmappedTerms.NAME, UnmappedTerms::new)
                 .addResultReader(LongTerms.NAME, LongTerms::new)
                 .addResultReader(DoubleTerms.NAME, DoubleTerms::new)
+                .addResultReader(UnsignedLongTerms.NAME, UnsignedLongTerms::new)
                 .setAggregatorRegistrar(TermsAggregationBuilder::registerAggregators),
             builder
         );
@@ -625,22 +629,6 @@ private ValuesSourceRegistry registerAggregations(List<SearchPlugin> plugins) {
             ).addResultReader(InternalGeoDistance::new).setAggregatorRegistrar(GeoDistanceAggregationBuilder::registerAggregators),
             builder
         );
-        registerAggregation(
-            new AggregationSpec(
-                GeoHashGridAggregationBuilder.NAME,
-                GeoHashGridAggregationBuilder::new,
-                GeoHashGridAggregationBuilder.PARSER
-            ).addResultReader(InternalGeoHashGrid::new).setAggregatorRegistrar(GeoHashGridAggregationBuilder::registerAggregators),
-            builder
-        );
-        registerAggregation(
-            new AggregationSpec(
-                GeoTileGridAggregationBuilder.NAME,
-                GeoTileGridAggregationBuilder::new,
-                GeoTileGridAggregationBuilder.PARSER
-            ).addResultReader(InternalGeoTileGrid::new).setAggregatorRegistrar(GeoTileGridAggregationBuilder::registerAggregators),
-            builder
-        );
         registerAggregation(
             new AggregationSpec(NestedAggregationBuilder.NAME, NestedAggregationBuilder::new, NestedAggregationBuilder::parse)
                 .addResultReader(InternalNested::new),
@@ -659,12 +647,6 @@ private ValuesSourceRegistry registerAggregations(List<SearchPlugin> plugins) {
                 .addResultReader(InternalTopHits::new),
             builder
         );
-        registerAggregation(
-            new AggregationSpec(GeoBoundsAggregationBuilder.NAME, GeoBoundsAggregationBuilder::new, GeoBoundsAggregationBuilder.PARSER)
-                .addResultReader(InternalGeoBounds::new)
-                .setAggregatorRegistrar(GeoBoundsAggregationBuilder::registerAggregators),
-            builder
-        );
         registerAggregation(
             new AggregationSpec(
                 GeoCentroidAggregationBuilder.NAME,
@@ -684,7 +666,13 @@ private ValuesSourceRegistry registerAggregations(List<SearchPlugin> plugins) {
         registerAggregation(
             new AggregationSpec(CompositeAggregationBuilder.NAME, CompositeAggregationBuilder::new, CompositeAggregationBuilder.PARSER)
                 .addResultReader(InternalComposite::new)
-                .setAggregatorRegistrar(CompositeAggregationBuilder::registerAggregators),
+                .setAggregatorRegistrar(reg -> CompositeAggregationBuilder.registerAggregators(reg, plugins)),
+            builder
+        );
+        registerAggregation(
+            new AggregationSpec(MultiTermsAggregationBuilder.NAME, MultiTermsAggregationBuilder::new, MultiTermsAggregationBuilder.PARSER)
+                .addResultReader(InternalMultiTerms::new)
+                .setAggregatorRegistrar(MultiTermsAggregationFactory::registerAggregators),
             builder
         );
         registerFromPlugin(plugins, SearchPlugin::getAggregations, (agg) -> this.registerAggregation(agg, builder));
@@ -1044,6 +1032,7 @@ private void registerValueFormats() {
         registerValueFormat(DocValueFormat.RAW.getWriteableName(), in -> DocValueFormat.RAW);
         registerValueFormat(DocValueFormat.BINARY.getWriteableName(), in -> DocValueFormat.BINARY);
         registerValueFormat(DocValueFormat.UNSIGNED_LONG_SHIFTED.getWriteableName(), in -> DocValueFormat.UNSIGNED_LONG_SHIFTED);
+        registerValueFormat(DocValueFormat.UNSIGNED_LONG.getWriteableName(), in -> DocValueFormat.UNSIGNED_LONG);
     }
 
     /**
@@ -1305,6 +1294,9 @@ private QueryPhaseSearcher registerQueryPhaseSearcher(List<SearchPlugin> plugins
             }
         }
 
+        if (searcher == null) {
+            searcher = new QueryPhaseSearcherWrapper();
+        }
         return searcher;
     }
 
@@ -1323,6 +1315,9 @@ private SearchPlugin.ExecutorServiceProvider registerIndexSearcherExecutorProvid
             }
         }
 
+        if (provider == null && FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            provider = (ThreadPool threadPool) -> threadPool.executor(INDEX_SEARCHER);
+        }
         return provider;
     }
 
@@ -1331,10 +1326,10 @@ public FetchPhase getFetchPhase() {
     }
 
     public QueryPhase getQueryPhase() {
-        return (queryPhaseSearcher == null) ? new QueryPhase() : new QueryPhase(queryPhaseSearcher);
+        return new QueryPhase(queryPhaseSearcher);
     }
 
     public @Nullable ExecutorService getIndexSearcherExecutor(ThreadPool pool) {
-        return (indexSearcherExecutorProvider == null) ? null : indexSearcherExecutorProvider.getExecutor(pool);
+        return (indexSearcherExecutorProvider != null) ? indexSearcherExecutorProvider.getExecutor(pool) : null;
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/SearchParseException.java b/server/src/main/java/org/opensearch/search/SearchParseException.java
index 65d16f2b4aa41..389df1001d0c9 100644
--- a/server/src/main/java/org/opensearch/search/SearchParseException.java
+++ b/server/src/main/java/org/opensearch/search/SearchParseException.java
@@ -33,14 +33,19 @@
 package org.opensearch.search;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
 
 import java.io.IOException;
 
+/**
+ * Main error thrown if there is a problem during parsing a query
+ *
+ * @opensearch.internal
+ */
 public class SearchParseException extends SearchException {
 
     public static final int UNKNOWN_POSITION = -1;
diff --git a/server/src/main/java/org/opensearch/search/SearchPhaseResult.java b/server/src/main/java/org/opensearch/search/SearchPhaseResult.java
index 86472e74d6658..9eda278a40268 100644
--- a/server/src/main/java/org/opensearch/search/SearchPhaseResult.java
+++ b/server/src/main/java/org/opensearch/search/SearchPhaseResult.java
@@ -33,13 +33,13 @@
 package org.opensearch.search;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.search.fetch.FetchSearchResult;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.query.QuerySearchResult;
-import org.opensearch.transport.TransportResponse;
 
 import java.io.IOException;
 
@@ -50,6 +50,8 @@
  * request ID is particularly important since it is used to reference and maintain a context
  * across search phases to ensure the same point in time snapshot is used for querying and
  * fetching etc.
+ *
+ * @opensearch.internal
  */
 public abstract class SearchPhaseResult extends TransportResponse {
 
diff --git a/server/src/main/java/org/opensearch/search/SearchService.java b/server/src/main/java/org/opensearch/search/SearchService.java
index 5a5f223d33e60..a9e7dcdbc8a7c 100644
--- a/server/src/main/java/org/opensearch/search/SearchService.java
+++ b/server/src/main/java/org/opensearch/search/SearchService.java
@@ -38,35 +38,42 @@
 import org.apache.lucene.search.TopDocs;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.DeletePitInfo;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.ListPitInfo;
+import org.opensearch.action.search.PitSearchContextIdForNode;
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.action.search.SearchType;
+import org.opensearch.action.search.UpdatePitContextRequest;
+import org.opensearch.action.search.UpdatePitContextResponse;
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedSupplier;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.ConcurrentMapLong;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
@@ -81,9 +88,7 @@
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.SearchOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
 import org.opensearch.node.ResponseCollectorService;
 import org.opensearch.script.FieldScript;
@@ -111,6 +116,7 @@
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
 import org.opensearch.search.internal.LegacyReaderContext;
+import org.opensearch.search.internal.PitReaderContext;
 import org.opensearch.search.internal.ReaderContext;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.internal.ShardSearchContextId;
@@ -127,6 +133,7 @@
 import org.opensearch.search.sort.MinAndMax;
 import org.opensearch.search.sort.SortAndFormats;
 import org.opensearch.search.sort.SortBuilder;
+import org.opensearch.search.sort.SortOrder;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.completion.CompletionSuggestion;
 import org.opensearch.threadpool.Scheduler.Cancellable;
@@ -135,10 +142,12 @@
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
@@ -151,6 +160,11 @@
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.common.unit.TimeValue.timeValueMinutes;
 
+/**
+ * The main search service
+ *
+ * @opensearch.internal
+ */
 public class SearchService extends AbstractLifecycleComponent implements IndexEventListener {
     private static final Logger logger = LogManager.getLogger(SearchService.class);
 
@@ -161,6 +175,15 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
         Property.NodeScope,
         Property.Dynamic
     );
+    /**
+     * This setting will help validate the max keep alive that can be set during creation or extension for a PIT reader context
+     */
+    public static final Setting<TimeValue> MAX_PIT_KEEPALIVE_SETTING = Setting.positiveTimeSetting(
+        "point_in_time.max_keep_alive",
+        timeValueHours(24),
+        Property.NodeScope,
+        Property.Dynamic
+    );
     public static final Setting<TimeValue> MAX_KEEPALIVE_SETTING = Setting.positiveTimeSetting(
         "search.max_keep_alive",
         timeValueHours(24),
@@ -213,6 +236,26 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
         Property.NodeScope
     );
 
+    /**
+     * This setting defines the maximum number of active PIT reader contexts in the node , since each PIT context
+     * has a resource cost attached to it. This setting is less than scroll since users are
+     * encouraged to share the PIT details.
+     */
+    public static final Setting<Integer> MAX_OPEN_PIT_CONTEXT = Setting.intSetting(
+        "search.max_open_pit_context",
+        300,
+        0,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
+    public static final Setting<Boolean> CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING = Setting.boolSetting(
+        "search.concurrent_segment_search.enabled",
+        true,
+        Property.Dynamic,
+        Property.NodeScope
+    );
+
     public static final int DEFAULT_SIZE = 10;
     public static final int DEFAULT_FROM = 0;
 
@@ -238,6 +281,8 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
 
     private volatile long maxKeepAlive;
 
+    private volatile long maxPitKeepAlive;
+
     private volatile TimeValue defaultSearchTimeout;
 
     private volatile boolean defaultAllowPartialSearchResults;
@@ -246,6 +291,8 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
 
     private volatile int maxOpenScrollContext;
 
+    private volatile int maxOpenPitContext;
+
     private final Cancellable keepAliveReaper;
 
     private final AtomicLong idGenerator = new AtomicLong();
@@ -255,6 +302,7 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
     private final MultiBucketConsumerService multiBucketConsumerService;
 
     private final AtomicInteger openScrollContexts = new AtomicInteger();
+    private final AtomicInteger openPitContexts = new AtomicInteger();
     private final String sessionId = UUIDs.randomBase64UUID();
     private final Executor indexSearcherExecutor;
 
@@ -285,9 +333,16 @@ public SearchService(
             circuitBreakerService.getBreaker(CircuitBreaker.REQUEST)
         );
         this.indexSearcherExecutor = indexSearcherExecutor;
-
         TimeValue keepAliveInterval = KEEPALIVE_INTERVAL_SETTING.get(settings);
         setKeepAlives(DEFAULT_KEEPALIVE_SETTING.get(settings), MAX_KEEPALIVE_SETTING.get(settings));
+        setPitKeepAlives(DEFAULT_KEEPALIVE_SETTING.get(settings), MAX_PIT_KEEPALIVE_SETTING.get(settings));
+        clusterService.getClusterSettings()
+            .addSettingsUpdateConsumer(
+                DEFAULT_KEEPALIVE_SETTING,
+                MAX_PIT_KEEPALIVE_SETTING,
+                this::setPitKeepAlives,
+                this::validatePitKeepAlives
+            );
 
         clusterService.getClusterSettings()
             .addSettingsUpdateConsumer(DEFAULT_KEEPALIVE_SETTING, MAX_KEEPALIVE_SETTING, this::setKeepAlives, this::validateKeepAlives);
@@ -304,6 +359,9 @@ public SearchService(
         maxOpenScrollContext = MAX_OPEN_SCROLL_CONTEXT.get(settings);
         clusterService.getClusterSettings().addSettingsUpdateConsumer(MAX_OPEN_SCROLL_CONTEXT, this::setMaxOpenScrollContext);
 
+        maxOpenPitContext = MAX_OPEN_PIT_CONTEXT.get(settings);
+        clusterService.getClusterSettings().addSettingsUpdateConsumer(MAX_OPEN_PIT_CONTEXT, this::setMaxOpenPitContext);
+
         lowLevelCancellation = LOW_LEVEL_CANCELLATION_SETTING.get(settings);
         clusterService.getClusterSettings().addSettingsUpdateConsumer(LOW_LEVEL_CANCELLATION_SETTING, this::setLowLevelCancellation);
     }
@@ -326,12 +384,38 @@ private void validateKeepAlives(TimeValue defaultKeepAlive, TimeValue maxKeepAli
         }
     }
 
+    /**
+     * Default keep alive search setting should be less than max PIT keep alive
+     */
+    private void validatePitKeepAlives(TimeValue defaultKeepAlive, TimeValue maxPitKeepAlive) {
+        if (defaultKeepAlive.millis() > maxPitKeepAlive.millis()) {
+            throw new IllegalArgumentException(
+                "Default keep alive setting for request ["
+                    + DEFAULT_KEEPALIVE_SETTING.getKey()
+                    + "]"
+                    + " should be smaller than max keep alive for PIT ["
+                    + MAX_PIT_KEEPALIVE_SETTING.getKey()
+                    + "], "
+                    + "was ("
+                    + defaultKeepAlive
+                    + " > "
+                    + maxPitKeepAlive
+                    + ")"
+            );
+        }
+    }
+
     private void setKeepAlives(TimeValue defaultKeepAlive, TimeValue maxKeepAlive) {
         validateKeepAlives(defaultKeepAlive, maxKeepAlive);
         this.defaultKeepAlive = defaultKeepAlive.millis();
         this.maxKeepAlive = maxKeepAlive.millis();
     }
 
+    private void setPitKeepAlives(TimeValue defaultKeepAlive, TimeValue maxPitKeepAlive) {
+        validatePitKeepAlives(defaultKeepAlive, maxPitKeepAlive);
+        this.maxPitKeepAlive = maxPitKeepAlive.millis();
+    }
+
     private void setDefaultSearchTimeout(TimeValue defaultSearchTimeout) {
         this.defaultSearchTimeout = defaultSearchTimeout;
     }
@@ -348,6 +432,10 @@ private void setMaxOpenScrollContext(int maxOpenScrollContext) {
         this.maxOpenScrollContext = maxOpenScrollContext;
     }
 
+    private void setMaxOpenPitContext(int maxOpenPitContext) {
+        this.maxOpenPitContext = maxOpenPitContext;
+    }
+
     private void setLowLevelCancellation(Boolean lowLevelCancellation) {
         this.lowLevelCancellation = lowLevelCancellation;
     }
@@ -788,32 +876,101 @@ final ReaderContext createAndPutReaderContext(
      * Opens the reader context for given shardId. The newly opened reader context will be keep
      * until the {@code keepAlive} elapsed unless it is manually released.
      */
-    public void openReaderContext(ShardId shardId, TimeValue keepAlive, ActionListener<ShardSearchContextId> listener) {
-        checkKeepAliveLimit(keepAlive.millis());
+    public void createPitReaderContext(ShardId shardId, TimeValue keepAlive, ActionListener<ShardSearchContextId> listener) {
+        checkPitKeepAliveLimit(keepAlive.millis());
         final IndexService indexService = indicesService.indexServiceSafe(shardId.getIndex());
         final IndexShard shard = indexService.getShard(shardId.id());
         final SearchOperationListener searchOperationListener = shard.getSearchOperationListener();
         shard.awaitShardSearchActive(ignored -> {
             Engine.SearcherSupplier searcherSupplier = null;
             ReaderContext readerContext = null;
+            Releasable decreasePitContexts = openPitContexts::decrementAndGet;
             try {
+                if (openPitContexts.incrementAndGet() > maxOpenPitContext) {
+                    throw new OpenSearchRejectedExecutionException(
+                        "Trying to create too many Point In Time contexts. Must be less than or equal to: ["
+                            + maxOpenPitContext
+                            + "]. "
+                            + "This limit can be set by changing the ["
+                            + MAX_OPEN_PIT_CONTEXT.getKey()
+                            + "] setting."
+                    );
+                }
                 searcherSupplier = shard.acquireSearcherSupplier();
                 final ShardSearchContextId id = new ShardSearchContextId(sessionId, idGenerator.incrementAndGet());
-                readerContext = new ReaderContext(id, indexService, shard, searcherSupplier, keepAlive.millis(), false);
+                readerContext = new PitReaderContext(id, indexService, shard, searcherSupplier, keepAlive.millis(), false);
                 final ReaderContext finalReaderContext = readerContext;
                 searcherSupplier = null; // transfer ownership to reader context
+
                 searchOperationListener.onNewReaderContext(readerContext);
-                readerContext.addOnClose(() -> searchOperationListener.onFreeReaderContext(finalReaderContext));
+                searchOperationListener.onNewPitContext(finalReaderContext);
+
+                readerContext.addOnClose(() -> {
+                    searchOperationListener.onFreeReaderContext(finalReaderContext);
+                    searchOperationListener.onFreePitContext(finalReaderContext);
+                });
+                readerContext.addOnClose(decreasePitContexts);
+                // add the newly created pit reader context to active readers
                 putReaderContext(readerContext);
                 readerContext = null;
                 listener.onResponse(finalReaderContext.id());
             } catch (Exception exc) {
+                Releasables.closeWhileHandlingException(decreasePitContexts);
                 Releasables.closeWhileHandlingException(searcherSupplier, readerContext);
                 listener.onFailure(exc);
             }
         });
     }
 
+    /**
+     * Update PIT reader with pit id, keep alive and created time etc
+     */
+    public void updatePitIdAndKeepAlive(UpdatePitContextRequest request, ActionListener<UpdatePitContextResponse> listener) {
+        checkPitKeepAliveLimit(request.getKeepAlive());
+        PitReaderContext readerContext = getPitReaderContext(request.getSearchContextId());
+        if (readerContext == null) {
+            throw new SearchContextMissingException(request.getSearchContextId());
+        }
+        Releasable updatePit = null;
+        try {
+            updatePit = readerContext.updatePitIdAndKeepAlive(request.getKeepAlive(), request.getPitId(), request.getCreationTime());
+            listener.onResponse(new UpdatePitContextResponse(request.getPitId(), request.getCreationTime(), request.getKeepAlive()));
+        } catch (Exception e) {
+            freeReaderContext(readerContext.id());
+            listener.onFailure(e);
+        } finally {
+            if (updatePit != null) {
+                updatePit.close();
+            }
+        }
+    }
+
+    /**
+     * Returns pit reader context based on ID
+     */
+    public PitReaderContext getPitReaderContext(ShardSearchContextId id) {
+        ReaderContext context = activeReaders.get(id.getId());
+        if (context instanceof PitReaderContext) {
+            return (PitReaderContext) context;
+        }
+        return null;
+    }
+
+    /**
+     * This method returns all active PIT reader contexts
+     */
+    public List<ListPitInfo> getAllPITReaderContexts() {
+        final List<ListPitInfo> pitContextsInfo = new ArrayList<>();
+        for (ReaderContext ctx : activeReaders.values()) {
+            if (ctx instanceof PitReaderContext) {
+                final PitReaderContext context = (PitReaderContext) ctx;
+                ListPitInfo pitInfo = new ListPitInfo(context.getPitId(), context.getCreationTime(), context.getKeepAlive());
+                pitContextsInfo.add(pitInfo);
+            }
+        }
+        return pitContextsInfo;
+    }
+
     final SearchContext createContext(
         ReaderContext readerContext,
         ShardSearchRequest request,
@@ -889,7 +1046,8 @@ private DefaultSearchContext createSearchContext(ReaderContext reader, ShardSear
                 lowLevelCancellation,
                 clusterService.state().nodes().getMinNodeVersion(),
                 validate,
-                indexSearcherExecutor
+                indexSearcherExecutor,
+                this::aggReduceContextBuilder
             );
             // we clone the query shard context here just for rewriting otherwise we
             // might end up with incorrect state since we are using now() or script services
@@ -935,11 +1093,50 @@ public void freeAllScrollContexts() {
         }
     }
 
+    /**
+     * Free reader contexts if found
+     * @return response with list of PIT IDs deleted and if operation is successful
+     */
+    public DeletePitResponse freeReaderContextsIfFound(List<PitSearchContextIdForNode> contextIds) {
+        List<DeletePitInfo> deleteResults = new ArrayList<>();
+        for (PitSearchContextIdForNode contextId : contextIds) {
+            try {
+                if (getReaderContext(contextId.getSearchContextIdForNode().getSearchContextId()) != null) {
+                    try (ReaderContext context = removeReaderContext(contextId.getSearchContextIdForNode().getSearchContextId().getId())) {
+                        PitReaderContext pitReaderContext = (PitReaderContext) context;
+                        if (context == null) {
+                            DeletePitInfo deletePitInfo = new DeletePitInfo(true, contextId.getPitId());
+                            deleteResults.add(deletePitInfo);
+                            continue;
+                        }
+                        String pitId = pitReaderContext.getPitId();
+                        boolean success = context != null;
+                        DeletePitInfo deletePitInfo = new DeletePitInfo(success, pitId);
+                        deleteResults.add(deletePitInfo);
+                    }
+                } else {
+                    // For search context missing cases, mark the operation as succeeded
+                    DeletePitInfo deletePitInfo = new DeletePitInfo(true, contextId.getPitId());
+                    deleteResults.add(deletePitInfo);
+                }
+            } catch (SearchContextMissingException e) {
+                // For search context missing cases, mark the operation as succeeded
+                DeletePitInfo deletePitInfo = new DeletePitInfo(true, contextId.getPitId());
+                deleteResults.add(deletePitInfo);
+            }
+        }
+        return new DeletePitResponse(deleteResults);
+    }
+
     private long getKeepAlive(ShardSearchRequest request) {
         if (request.scroll() != null) {
             return getScrollKeepAlive(request.scroll());
         } else if (request.keepAlive() != null) {
-            checkKeepAliveLimit(request.keepAlive().millis());
+            if (getReaderContext(request.readerId()) instanceof PitReaderContext) {
+                checkPitKeepAliveLimit(request.keepAlive().millis());
+            } else {
+                checkKeepAliveLimit(request.keepAlive().millis());
+            }
             return request.keepAlive().getMillis();
         } else {
             return request.readerId() == null ? defaultKeepAlive : -1;
@@ -970,6 +1167,25 @@ private void checkKeepAliveLimit(long keepAlive) {
         }
     }
 
+    /**
+     * check if request keep alive is greater than max keep alive
+     */
+    private void checkPitKeepAliveLimit(long keepAlive) {
+        if (keepAlive > maxPitKeepAlive) {
+            throw new IllegalArgumentException(
+                "Keep alive for request ("
+                    + TimeValue.timeValueMillis(keepAlive)
+                    + ") is too large. "
+                    + "It must be less than ("
+                    + TimeValue.timeValueMillis(maxPitKeepAlive)
+                    + "). "
+                    + "This limit can be set by changing the ["
+                    + MAX_PIT_KEEPALIVE_SETTING.getKey()
+                    + "] cluster level setting."
+            );
+        }
+    }
+
     private <T> ActionListener<T> wrapFailureListener(ActionListener<T> listener, ReaderContext context, Releasable releasable) {
         return new ActionListener<T>() {
             @Override
@@ -1009,6 +1225,7 @@ private void processFailure(ReaderContext context, Exception exc) {
     private void parseSource(DefaultSearchContext context, SearchSourceBuilder source, boolean includeAggregations) {
         // nothing to parse...
         if (source == null) {
+            context.evaluateRequestShouldUseConcurrentSearch();
             return;
         }
         SearchShardTarget shardTarget = context.shardTarget();
@@ -1055,9 +1272,6 @@ private void parseSource(DefaultSearchContext context, SearchSourceBuilder sourc
         if (source.minScore() != null) {
             context.minimumScore(source.minScore());
         }
-        if (source.profile()) {
-            context.setProfilers(new Profilers(context.searcher()));
-        }
         if (source.timeout() != null) {
             context.timeout(source.timeout());
         }
@@ -1160,8 +1374,8 @@ private void parseSource(DefaultSearchContext context, SearchSourceBuilder sourc
         }
 
         if (source.slice() != null) {
-            if (context.scrollContext() == null) {
-                throw new SearchException(shardTarget, "`slice` cannot be used outside of a scroll context");
+            if (context.scrollContext() == null && !(context.readerContext() instanceof PitReaderContext)) {
+                throw new SearchException(shardTarget, "`slice` cannot be used outside of a scroll context or PIT context");
             }
             context.sliceBuilder(source.slice());
         }
@@ -1191,6 +1405,10 @@ private void parseSource(DefaultSearchContext context, SearchSourceBuilder sourc
             final CollapseContext collapseContext = source.collapse().build(queryShardContext);
             context.collapse(collapseContext);
         }
+        context.evaluateRequestShouldUseConcurrentSearch();
+        if (source.profile()) {
+            context.setProfilers(new Profilers(context.searcher(), context.shouldUseConcurrentSearch()));
+        }
     }
 
     /**
@@ -1319,7 +1537,7 @@ private CanMatchResponse canMatch(ShardSearchRequest request, boolean checkRefre
                 final boolean aliasFilterCanMatch = request.getAliasFilter().getQueryBuilder() instanceof MatchNoneQueryBuilder == false;
                 FieldSortBuilder sortBuilder = FieldSortBuilder.getPrimaryFieldSortOrNull(request.source());
                 MinAndMax<?> minMax = sortBuilder != null ? FieldSortBuilder.getMinMaxOrNull(context, sortBuilder) : null;
-                final boolean canMatch;
+                boolean canMatch;
                 if (canRewriteToMatchNone(request.source())) {
                     QueryBuilder queryBuilder = request.source().query();
                     canMatch = aliasFilterCanMatch && queryBuilder instanceof MatchNoneQueryBuilder == false;
@@ -1327,11 +1545,58 @@ private CanMatchResponse canMatch(ShardSearchRequest request, boolean checkRefre
                     // null query means match_all
                     canMatch = aliasFilterCanMatch;
                 }
+                final FieldDoc searchAfterFieldDoc = getSearchAfterFieldDoc(request, context);
+                final Integer trackTotalHitsUpto = request.source() == null ? null : request.source().trackTotalHitsUpTo();
+                canMatch = canMatch && canMatchSearchAfter(searchAfterFieldDoc, minMax, sortBuilder, trackTotalHitsUpto);
+
                 return new CanMatchResponse(canMatch || hasRefreshPending, minMax);
             }
         }
     }
 
+    public static boolean canMatchSearchAfter(
+        FieldDoc searchAfter,
+        MinAndMax<?> minMax,
+        FieldSortBuilder primarySortField,
+        Integer trackTotalHitsUpto
+    ) {
+        // Check for sort.missing == null, since in case of missing values sort queries, if segment/shard's min/max
+        // is out of search_after range, it still should be printed and hence we should not skip segment/shard.
+        // Skipping search on shard/segment entirely can cause mismatch on total_tracking_hits, hence skip only if
+        // track_total_hits is false.
+        if (searchAfter != null
+            && minMax != null
+            && primarySortField != null
+            && primarySortField.missing() == null
+            && Objects.equals(trackTotalHitsUpto, SearchContext.TRACK_TOTAL_HITS_DISABLED)) {
+            final Object searchAfterPrimary = searchAfter.fields[0];
+            if (primarySortField.order() == SortOrder.DESC) {
+                if (minMax.compareMin(searchAfterPrimary) > 0) {
+                    // In Desc order, if segment/shard minimum is gt search_after, the segment/shard won't be competitive
+                    return false;
+                }
+            } else {
+                if (minMax.compareMax(searchAfterPrimary) < 0) {
+                    // In ASC order, if segment/shard maximum is lt search_after, the segment/shard won't be competitive
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private static FieldDoc getSearchAfterFieldDoc(ShardSearchRequest request, QueryShardContext context) throws IOException {
+        if (context != null && request != null && request.source() != null && request.source().sorts() != null) {
+            final List<SortBuilder<?>> sorts = request.source().sorts();
+            final Object[] searchAfter = request.source().searchAfter();
+            final Optional<SortAndFormats> sortOpt = SortBuilder.buildSort(sorts, context);
+            if (sortOpt.isPresent() && !CollectionUtils.isEmpty(searchAfter)) {
+                return SearchAfterBuilder.buildFieldDoc(sortOpt.get(), searchAfter);
+            }
+        }
+        return null;
+    }
+
     /**
      * Returns true iff the given search source builder can be early terminated by rewriting to a match none query. Or in other words
      * if the execution of the search request can be early terminated without executing it. This is for instance not possible if
@@ -1380,22 +1645,22 @@ public IndicesService getIndicesService() {
 
     /**
      * Returns a builder for {@link InternalAggregation.ReduceContext}. This
-     * builder retains a reference to the provided {@link SearchRequest}.
+     * builder retains a reference to the provided {@link SearchSourceBuilder}.
      */
-    public InternalAggregation.ReduceContextBuilder aggReduceContextBuilder(SearchRequest request) {
+    public InternalAggregation.ReduceContextBuilder aggReduceContextBuilder(SearchSourceBuilder searchSourceBuilder) {
         return new InternalAggregation.ReduceContextBuilder() {
             @Override
             public InternalAggregation.ReduceContext forPartialReduction() {
                 return InternalAggregation.ReduceContext.forPartialReduction(
                     bigArrays,
                     scriptService,
-                    () -> requestToPipelineTree(request)
+                    () -> requestToPipelineTree(searchSourceBuilder)
                 );
             }
 
             @Override
             public ReduceContext forFinalReduction() {
-                PipelineTree pipelineTree = requestToPipelineTree(request);
+                PipelineTree pipelineTree = requestToPipelineTree(searchSourceBuilder);
                 return InternalAggregation.ReduceContext.forFinalReduction(
                     bigArrays,
                     scriptService,
@@ -1406,13 +1671,18 @@ public ReduceContext forFinalReduction() {
         };
     }
 
-    private static PipelineTree requestToPipelineTree(SearchRequest request) {
-        if (request.source() == null || request.source().aggregations() == null) {
+    private static PipelineTree requestToPipelineTree(SearchSourceBuilder searchSourceBuilder) {
+        if (searchSourceBuilder == null || searchSourceBuilder.aggregations() == null) {
             return PipelineTree.EMPTY;
         }
-        return request.source().aggregations().buildPipelineTree();
+        return searchSourceBuilder.aggregations().buildPipelineTree();
     }
 
+    /**
+     * Search phase result that can match a response
+     *
+     * @opensearch.internal
+     */
     public static final class CanMatchResponse extends SearchPhaseResult {
         private final boolean canMatch;
         private final MinAndMax<?> estimatedMinAndMax;
diff --git a/server/src/main/java/org/opensearch/search/SearchShardTarget.java b/server/src/main/java/org/opensearch/search/SearchShardTarget.java
index 32e5400576ad9..882ba8e069c2e 100644
--- a/server/src/main/java/org/opensearch/search/SearchShardTarget.java
+++ b/server/src/main/java/org/opensearch/search/SearchShardTarget.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.transport.RemoteClusterAware;
 
 import java.io.IOException;
@@ -46,6 +46,8 @@
 
 /**
  * The target that the search request was executed on.
+ *
+ * @opensearch.internal
  */
 public final class SearchShardTarget implements Writeable, Comparable<SearchShardTarget> {
 
diff --git a/server/src/main/java/org/opensearch/search/SearchSortValues.java b/server/src/main/java/org/opensearch/search/SearchSortValues.java
index aa234685b9407..c1f6b45ded7a5 100644
--- a/server/src/main/java/org/opensearch/search/SearchSortValues.java
+++ b/server/src/main/java/org/opensearch/search/SearchSortValues.java
@@ -33,20 +33,25 @@
 package org.opensearch.search;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.SearchHit.Fields;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Objects;
 
+/**
+ * Values to sort during search
+ *
+ * @opensearch.internal
+ */
 public class SearchSortValues implements ToXContentFragment, Writeable {
 
     private static final Object[] EMPTY_ARRAY = new Object[0];
@@ -74,6 +79,8 @@ public SearchSortValues(Object[] rawSortValues, DocValueFormat[] sortValueFormat
                 this.formattedSortValues[i] = sortValueFormats[i].format((BytesRef) sortValue);
             } else if ((sortValue instanceof Long) && (sortValueFormats[i] == DocValueFormat.UNSIGNED_LONG_SHIFTED)) {
                 this.formattedSortValues[i] = sortValueFormats[i].format((Long) sortValue);
+            } else if ((sortValue instanceof Long) && (sortValueFormats[i] == DocValueFormat.UNSIGNED_LONG)) {
+                this.formattedSortValues[i] = sortValueFormats[i].format((Long) sortValue);
             } else {
                 this.formattedSortValues[i] = sortValue;
             }
diff --git a/server/src/main/java/org/opensearch/search/SearchSortValuesAndFormats.java b/server/src/main/java/org/opensearch/search/SearchSortValuesAndFormats.java
index 74bc2bd50f62a..c2e9ea2a35a3e 100644
--- a/server/src/main/java/org/opensearch/search/SearchSortValuesAndFormats.java
+++ b/server/src/main/java/org/opensearch/search/SearchSortValuesAndFormats.java
@@ -33,14 +33,20 @@
 package org.opensearch.search;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Arrays;
 
+/**
+ * Doc value and formats to sort during search
+ *
+ * @opensearch.internal
+ */
 public class SearchSortValuesAndFormats implements Writeable {
     private final Object[] rawSortValues;
     private final Object[] formattedSortValues;
@@ -57,6 +63,8 @@ public SearchSortValuesAndFormats(Object[] rawSortValues, DocValueFormat[] sortV
                 this.formattedSortValues[i] = sortValueFormats[i].format((BytesRef) sortValue);
             } else if (sortValue instanceof Long) {
                 this.formattedSortValues[i] = sortValueFormats[i].format((long) sortValue);
+            } else if (sortValue instanceof BigInteger) {
+                this.formattedSortValues[i] = sortValueFormats[i].format((BigInteger) sortValue);
             } else if (sortValue instanceof Double) {
                 this.formattedSortValues[i] = sortValueFormats[i].format((double) sortValue);
             } else if (sortValue instanceof Float || sortValue instanceof Integer) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AbstractAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/AbstractAggregationBuilder.java
index 8b5bbc9f28d8f..d3f17a58874bc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AbstractAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AbstractAggregationBuilder.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 
 import java.io.IOException;
@@ -43,6 +43,8 @@
 
 /**
  * Base implementation of a {@link AggregationBuilder}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractAggregationBuilder<AB extends AbstractAggregationBuilder<AB>> extends AggregationBuilder {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/Aggregation.java b/server/src/main/java/org/opensearch/search/aggregations/Aggregation.java
index 6c4a4ce8dd664..b723e14a84cbe 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/Aggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/Aggregation.java
@@ -31,14 +31,16 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
 
 import java.util.Map;
 
 /**
  * An aggregation. Extends {@link ToXContent} as it makes it easier to print out its content.
+ *
+ * @opensearch.internal
  */
 public interface Aggregation extends ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilder.java
index 1e372aff17cd4..0d4d4bd7d67b2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilder.java
@@ -31,11 +31,12 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.Rewriteable;
@@ -48,6 +49,8 @@
 
 /**
  * A factory that knows how to create an {@link Aggregator} of a specific type.
+ *
+ * @opensearch.internal
  */
 public abstract class AggregationBuilder
     implements
@@ -164,6 +167,8 @@ public PipelineTree buildPipelineTree() {
      * <p>
      * Unlike {@link CardinalityUpperBound} which is <strong>total</strong>
      * instead of <strong>per parent bucket</strong>.
+     *
+     * @opensearch.internal
      */
     public enum BucketCardinality {
         NONE,
@@ -177,13 +182,17 @@ public enum BucketCardinality {
      */
     public abstract BucketCardinality bucketCardinality();
 
-    /** Common xcontent fields shared among aggregator builders */
+    /**
+     * Common xcontent fields shared among aggregator builders
+     *
+     * @opensearch.internal
+     */
     public static final class CommonFields extends ParseField.CommonFields {
         public static final ParseField VALUE_TYPE = new ParseField("value_type");
     }
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilders.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilders.java
index 99a1107675edf..9886e423bbc76 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilders.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationBuilders.java
@@ -43,10 +43,6 @@
 import org.opensearch.search.aggregations.bucket.filter.Filters;
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregator.KeyedFilter;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.InternalGeoHashGrid;
-import org.opensearch.search.aggregations.bucket.geogrid.InternalGeoTileGrid;
 import org.opensearch.search.aggregations.bucket.global.Global;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramAggregationBuilder;
@@ -66,6 +62,7 @@
 import org.opensearch.search.aggregations.bucket.sampler.DiversifiedAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.sampler.Sampler;
 import org.opensearch.search.aggregations.bucket.sampler.SamplerAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTextAggregationBuilder;
@@ -77,8 +74,6 @@
 import org.opensearch.search.aggregations.metrics.CardinalityAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.ExtendedStats;
 import org.opensearch.search.aggregations.metrics.ExtendedStatsAggregationBuilder;
-import org.opensearch.search.aggregations.metrics.GeoBounds;
-import org.opensearch.search.aggregations.metrics.GeoBoundsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.GeoCentroid;
 import org.opensearch.search.aggregations.metrics.GeoCentroidAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.Max;
@@ -108,6 +103,8 @@
 
 /**
  * Utility class to create aggregations.
+ *
+ * @opensearch.internal
  */
 public class AggregationBuilders {
 
@@ -260,20 +257,6 @@ public static HistogramAggregationBuilder histogram(String name) {
         return new HistogramAggregationBuilder(name);
     }
 
-    /**
-     * Create a new {@link InternalGeoHashGrid} aggregation with the given name.
-     */
-    public static GeoHashGridAggregationBuilder geohashGrid(String name) {
-        return new GeoHashGridAggregationBuilder(name);
-    }
-
-    /**
-     * Create a new {@link InternalGeoTileGrid} aggregation with the given name.
-     */
-    public static GeoTileGridAggregationBuilder geotileGrid(String name) {
-        return new GeoTileGridAggregationBuilder(name);
-    }
-
     /**
      * Create a new {@link SignificantTerms} aggregation with the given name.
      */
@@ -361,13 +344,6 @@ public static TopHitsAggregationBuilder topHits(String name) {
         return new TopHitsAggregationBuilder(name);
     }
 
-    /**
-     * Create a new {@link GeoBounds} aggregation with the given name.
-     */
-    public static GeoBoundsAggregationBuilder geoBounds(String name) {
-        return new GeoBoundsAggregationBuilder(name);
-    }
-
     /**
      * Create a new {@link GeoCentroid} aggregation with the given name.
      */
@@ -388,4 +364,11 @@ public static ScriptedMetricAggregationBuilder scriptedMetric(String name) {
     public static CompositeAggregationBuilder composite(String name, List<CompositeValuesSourceBuilder<?>> sources) {
         return new CompositeAggregationBuilder(name, sources);
     }
+
+    /**
+     * Create a new {@link MultiTermsAggregationBuilder} aggregation with the given name.
+     */
+    public static MultiTermsAggregationBuilder multiTerms(String name) {
+        return new MultiTermsAggregationBuilder(name);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationCollectorManager.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationCollectorManager.java
new file mode 100644
index 0000000000000..d48efc2391cdc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationCollectorManager.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Common {@link CollectorManager} used by both concurrent and non-concurrent aggregation path and also for global and non-global
+ * aggregation operators
+ *
+ * @opensearch.internal
+ */
+public abstract class AggregationCollectorManager implements CollectorManager<Collector, ReduceableSearchResult> {
+    protected final SearchContext context;
+    private final CheckedFunction<SearchContext, List<Aggregator>, IOException> aggProvider;
+    private final String collectorReason;
+
+    AggregationCollectorManager(
+        SearchContext context,
+        CheckedFunction<SearchContext, List<Aggregator>, IOException> aggProvider,
+        String collectorReason
+    ) {
+        this.context = context;
+        this.aggProvider = aggProvider;
+        this.collectorReason = collectorReason;
+    }
+
+    @Override
+    public Collector newCollector() throws IOException {
+        final Collector collector = createCollector(aggProvider.apply(context));
+        // For Aggregations we should not have a NO_OP_Collector
+        assert collector != BucketCollector.NO_OP_COLLECTOR;
+        return collector;
+    }
+
+    public String getCollectorReason() {
+        return collectorReason;
+    }
+
+    public abstract String getCollectorName();
+
+    @Override
+    public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+        final List<Aggregator> aggregators = context.bucketCollectorProcessor().toAggregators(collectors);
+        final List<InternalAggregation> internals = new ArrayList<>(aggregators.size());
+        context.aggregations().resetBucketMultiConsumer();
+        for (Aggregator aggregator : aggregators) {
+            try {
+                // post collection is called in ContextIndexSearcher after search on leaves are completed
+                internals.add(aggregator.buildTopLevel());
+            } catch (IOException e) {
+                throw new AggregationExecutionException("Failed to build aggregation [" + aggregator.name() + "]", e);
+            }
+        }
+
+        // PipelineTreeSource is serialized to the coordinators on older OpenSearch versions for bwc but is deprecated in latest release
+        // To handle that we need to add it in the InternalAggregations object sent in QuerySearchResult.
+        final InternalAggregations internalAggregations = new InternalAggregations(
+            internals,
+            context.request().source().aggregations()::buildPipelineTree
+        );
+        return buildAggregationResult(internalAggregations);
+    }
+
+    protected AggregationReduceableSearchResult buildAggregationResult(InternalAggregations internalAggregations) {
+        return new AggregationReduceableSearchResult(internalAggregations);
+    }
+
+    static Collector createCollector(List<Aggregator> collectors) throws IOException {
+        Collector collector = MultiBucketCollector.wrap(collectors);
+        ((BucketCollector) collector).preCollection();
+        return collector;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationExecutionException.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationExecutionException.java
index 5bb65bc33fcde..c211b9cf5f344 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregationExecutionException.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationExecutionException.java
@@ -32,12 +32,14 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown when failing to execute an aggregation
+ *
+ * @opensearch.internal
  */
 public class AggregationExecutionException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationInitializationException.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationInitializationException.java
index c73cd7670b3fd..1159023cb6be2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregationInitializationException.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationInitializationException.java
@@ -32,12 +32,14 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown when failing to execute an aggregation
+ *
+ * @opensearch.internal
  */
 public class AggregationInitializationException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationPhase.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationPhase.java
deleted file mode 100644
index be62b33adb356..0000000000000
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregationPhase.java
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations;
-
-import org.apache.lucene.search.Collector;
-import org.apache.lucene.search.Query;
-import org.opensearch.common.inject.Inject;
-import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.search.aggregations.bucket.global.GlobalAggregator;
-import org.opensearch.search.internal.SearchContext;
-import org.opensearch.search.profile.query.CollectorResult;
-import org.opensearch.search.profile.query.InternalProfileCollector;
-import org.opensearch.search.query.QueryPhaseExecutionException;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
-/**
- * Aggregation phase of a search request, used to collect aggregations
- */
-public class AggregationPhase {
-
-    @Inject
-    public AggregationPhase() {}
-
-    public void preProcess(SearchContext context) {
-        if (context.aggregations() != null) {
-            List<Aggregator> collectors = new ArrayList<>();
-            Aggregator[] aggregators;
-            try {
-                AggregatorFactories factories = context.aggregations().factories();
-                aggregators = factories.createTopLevelAggregators(context);
-                for (int i = 0; i < aggregators.length; i++) {
-                    if (aggregators[i] instanceof GlobalAggregator == false) {
-                        collectors.add(aggregators[i]);
-                    }
-                }
-                context.aggregations().aggregators(aggregators);
-                if (!collectors.isEmpty()) {
-                    Collector collector = MultiBucketCollector.wrap(collectors);
-                    ((BucketCollector) collector).preCollection();
-                    if (context.getProfilers() != null) {
-                        collector = new InternalProfileCollector(
-                            collector,
-                            CollectorResult.REASON_AGGREGATION,
-                            // TODO: report on child aggs as well
-                            Collections.emptyList()
-                        );
-                    }
-                    context.queryCollectors().put(AggregationPhase.class, collector);
-                }
-            } catch (IOException e) {
-                throw new AggregationInitializationException("Could not initialize aggregators", e);
-            }
-        }
-    }
-
-    public void execute(SearchContext context) {
-        if (context.aggregations() == null) {
-            context.queryResult().aggregations(null);
-            return;
-        }
-
-        if (context.queryResult().hasAggs()) {
-            // no need to compute the aggs twice, they should be computed on a per context basis
-            return;
-        }
-
-        Aggregator[] aggregators = context.aggregations().aggregators();
-        List<Aggregator> globals = new ArrayList<>();
-        for (int i = 0; i < aggregators.length; i++) {
-            if (aggregators[i] instanceof GlobalAggregator) {
-                globals.add(aggregators[i]);
-            }
-        }
-
-        // optimize the global collector based execution
-        if (!globals.isEmpty()) {
-            BucketCollector globalsCollector = MultiBucketCollector.wrap(globals);
-            Query query = context.buildFilteredQuery(Queries.newMatchAllQuery());
-
-            try {
-                final Collector collector;
-                if (context.getProfilers() == null) {
-                    collector = globalsCollector;
-                } else {
-                    InternalProfileCollector profileCollector = new InternalProfileCollector(
-                        globalsCollector,
-                        CollectorResult.REASON_AGGREGATION_GLOBAL,
-                        // TODO: report on sub collectors
-                        Collections.emptyList()
-                    );
-                    collector = profileCollector;
-                    // start a new profile with this collector
-                    context.getProfilers().addQueryProfiler().setCollector(profileCollector);
-                }
-                globalsCollector.preCollection();
-                context.searcher().search(query, collector);
-            } catch (Exception e) {
-                throw new QueryPhaseExecutionException(context.shardTarget(), "Failed to execute global aggregators", e);
-            }
-        }
-
-        List<InternalAggregation> aggregations = new ArrayList<>(aggregators.length);
-        context.aggregations().resetBucketMultiConsumer();
-        for (Aggregator aggregator : context.aggregations().aggregators()) {
-            try {
-                aggregator.postCollection();
-                aggregations.add(aggregator.buildTopLevel());
-            } catch (IOException e) {
-                throw new AggregationExecutionException("Failed to build aggregation [" + aggregator.name() + "]", e);
-            }
-        }
-        context.queryResult()
-            .aggregations(new InternalAggregations(aggregations, context.request().source().aggregations()::buildPipelineTree));
-
-        // disable aggregations so that they don't run on next pages in case of scrolling
-        context.aggregations(null);
-        context.queryCollectors().remove(AggregationPhase.class);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationProcessor.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationProcessor.java
new file mode 100644
index 0000000000000..5b3e2f2542dc2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationProcessor.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.opensearch.search.internal.SearchContext;
+
+/**
+ * Interface to define different stages of aggregation processing before and after document collection
+ */
+public interface AggregationProcessor {
+
+    /**
+     * Callback invoked before collection of documents are done
+     * @param context {@link SearchContext} for the request
+     */
+    void preProcess(SearchContext context);
+
+    /**
+     * Callback invoked after collection of documents are done
+     * @param context {@link SearchContext} for the request
+     */
+    void postProcess(SearchContext context);
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregationReduceableSearchResult.java b/server/src/main/java/org/opensearch/search/aggregations/AggregationReduceableSearchResult.java
new file mode 100644
index 0000000000000..27c08f1221f6d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregationReduceableSearchResult.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+
+/**
+ * {@link ReduceableSearchResult} returned by the {@link AggregationCollectorManager} which merges the aggregation with the one present in
+ * query results
+ */
+public class AggregationReduceableSearchResult implements ReduceableSearchResult {
+    private final InternalAggregations aggregations;
+
+    public AggregationReduceableSearchResult(InternalAggregations aggregations) {
+        this.aggregations = aggregations;
+    }
+
+    @Override
+    public void reduce(QuerySearchResult result) throws IOException {
+        if (!result.hasAggs()) {
+            result.aggregations(aggregations);
+        } else {
+            // the aggregations result from reduce of either global or non-global aggs is present so lets combine it with other aggs
+            // as well
+            final InternalAggregations existingAggregations = result.aggregations().expand();
+            final InternalAggregations finalReducedAggregations = InternalAggregations.merge(existingAggregations, aggregations);
+            result.aggregations(finalReducedAggregations);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java b/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
index 9360f03304cf2..b75ec7fe531a8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
@@ -31,11 +31,11 @@
 
 package org.opensearch.search.aggregations;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -49,10 +49,12 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.common.xcontent.XContentParserUtils.parseTypedKeysObject;
+import static org.opensearch.core.xcontent.XContentParserUtils.parseTypedKeysObject;
 
 /**
  * Represents a set of {@link Aggregation}s
+ *
+ * @opensearch.internal
  */
 public class Aggregations implements Iterable<Aggregation>, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/Aggregator.java b/server/src/main/java/org/opensearch/search/aggregations/Aggregator.java
index b38dfe123fdf4..b2ac0fdef04ef 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/Aggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/Aggregator.java
@@ -33,14 +33,14 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasable;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.support.AggregationPath;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.sort.SortOrder;
@@ -54,6 +54,8 @@
  * <p>
  * Be <strong>careful</strong> when adding methods to this class. If possible
  * make sure they have sensible default implementations.
+ *
+ * @opensearch.internal
  */
 public abstract class Aggregator extends BucketCollector implements Releasable {
 
@@ -61,6 +63,8 @@ public abstract class Aggregator extends BucketCollector implements Releasable {
      * Parses the aggregation request and creates the appropriate aggregator factory for it.
      *
      * @see AggregationBuilder
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface Parser {
@@ -155,6 +159,8 @@ public BucketComparator bucketComparator(String key, SortOrder order) {
 
     /**
      * Compare two buckets by their ordinal.
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface BucketComparator {
@@ -202,7 +208,11 @@ public final InternalAggregation buildTopLevel() throws IOException {
      */
     public void collectDebugInfo(BiConsumer<String, Object> add) {}
 
-    /** Aggregation mode for sub aggregations. */
+    /**
+     * Aggregation mode for sub aggregations.
+     *
+     * @opensearch.internal
+     */
     public enum SubAggCollectionMode implements Writeable {
 
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregatorBase.java b/server/src/main/java/org/opensearch/search/aggregations/AggregatorBase.java
index 09af84bc81144..392c65ce27aea 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregatorBase.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregatorBase.java
@@ -34,9 +34,9 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.ScoreMode;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.aggregations.support.ValuesSourceConfig;
 import org.opensearch.search.internal.SearchContext;
@@ -52,6 +52,8 @@
 
 /**
  * Base implementation for concrete aggregators.
+ *
+ * @opensearch.internal
  */
 public abstract class AggregatorBase extends Aggregator {
 
@@ -198,7 +200,7 @@ public Map<String, Object> metadata() {
 
     @Override
     public final LeafBucketCollector getLeafCollector(LeafReaderContext ctx) throws IOException {
-        preGetSubLeafCollectors();
+        preGetSubLeafCollectors(ctx);
         final LeafBucketCollector sub = collectableSubAggregators.getLeafCollector(ctx);
         return getLeafCollector(ctx, sub);
     }
@@ -207,7 +209,7 @@ public final LeafBucketCollector getLeafCollector(LeafReaderContext ctx) throws
      * Can be overridden by aggregator implementations that like the perform an operation before the leaf collectors
      * of children aggregators are instantiated for the next segment.
      */
-    protected void preGetSubLeafCollectors() throws IOException {}
+    protected void preGetSubLeafCollectors(LeafReaderContext ctx) throws IOException {}
 
     /**
      * Can be overridden by aggregator implementation to be called back when the collection phase starts.
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactories.java b/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactories.java
index 1dde4c782c9dc..9b8ebe0b4e5e4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactories.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactories.java
@@ -32,21 +32,23 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
 import org.opensearch.common.xcontent.SuggestingErrorOnUnknown;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.Rewriteable;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.global.GlobalAggregatorFactory;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator.PipelineTree;
@@ -58,6 +60,7 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -69,6 +72,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.function.Predicate;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -77,6 +81,8 @@
 
 /**
  * An immutable collection of {@link AggregatorFactories}.
+ *
+ * @opensearch.internal
  */
 public class AggregatorFactories {
     public static final Pattern VALID_AGG_NAME = Pattern.compile("[^\\[\\]>]+");
@@ -229,11 +235,18 @@ private static AggregatorFactories.Builder parseAggregators(XContentParser parse
             }
         }
 
-        return factories;
+        return factories.count() > 0 ? factories : null;
     }
 
     public static final AggregatorFactories EMPTY = new AggregatorFactories(new AggregatorFactory[0]);
 
+    private static final Predicate<AggregatorFactory> GLOBAL_AGGREGATOR_FACTORY_PREDICATE = new Predicate<>() {
+        @Override
+        public boolean test(AggregatorFactory o) {
+            return o instanceof GlobalAggregatorFactory;
+        }
+    };
+
     private AggregatorFactory[] factories;
 
     public static Builder builder() {
@@ -244,6 +257,15 @@ private AggregatorFactories(AggregatorFactory[] factories) {
         this.factories = factories;
     }
 
+    public boolean allFactoriesSupportConcurrentSearch() {
+        for (AggregatorFactory factory : factories) {
+            if (factory.supportsConcurrentSegmentSearch() == false || factory.evaluateChildFactories() == false) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     /**
      * Create all aggregators so that they can be consumed with multiple
      * buckets.
@@ -265,24 +287,48 @@ public Aggregator[] createSubAggregators(SearchContext searchContext, Aggregator
         return aggregators;
     }
 
-    public Aggregator[] createTopLevelAggregators(SearchContext searchContext) throws IOException {
+    public List<Aggregator> createTopLevelAggregators(SearchContext searchContext) throws IOException {
+        return createTopLevelAggregators(searchContext, (aggregatorFactory) -> true);
+    }
+
+    public List<Aggregator> createTopLevelGlobalAggregators(SearchContext searchContext) throws IOException {
+        return createTopLevelAggregators(searchContext, GLOBAL_AGGREGATOR_FACTORY_PREDICATE);
+    }
+
+    public List<Aggregator> createTopLevelNonGlobalAggregators(SearchContext searchContext) throws IOException {
+        return createTopLevelAggregators(searchContext, GLOBAL_AGGREGATOR_FACTORY_PREDICATE.negate());
+    }
+
+    private List<Aggregator> createTopLevelAggregators(SearchContext searchContext, Predicate<AggregatorFactory> factoryFilter)
+        throws IOException {
         // These aggregators are going to be used with a single bucket ordinal, no need to wrap the PER_BUCKET ones
-        Aggregator[] aggregators = new Aggregator[factories.length];
+        List<Aggregator> aggregators = new ArrayList<>();
         for (int i = 0; i < factories.length; i++) {
             /*
              * Top level aggs only collect from owningBucketOrd 0 which is
              * *exactly* what CardinalityUpperBound.ONE *means*.
              */
-            Aggregator factory = factories[i].create(searchContext, null, CardinalityUpperBound.ONE);
-            Profilers profilers = factory.context().getProfilers();
-            if (profilers != null) {
-                factory = new ProfilingAggregator(factory, profilers.getAggregationProfiler());
+            Aggregator factory;
+            if (factoryFilter.test(factories[i])) {
+                factory = factories[i].create(searchContext, null, CardinalityUpperBound.ONE);
+                Profilers profilers = factory.context().getProfilers();
+                if (profilers != null) {
+                    factory = new ProfilingAggregator(factory, profilers.getAggregationProfiler());
+                }
+                aggregators.add(factory);
             }
-            aggregators[i] = factory;
         }
         return aggregators;
     }
 
+    public boolean hasNonGlobalAggregator() {
+        return Arrays.stream(factories).anyMatch(GLOBAL_AGGREGATOR_FACTORY_PREDICATE.negate());
+    }
+
+    public boolean hasGlobalAggregator() {
+        return Arrays.stream(factories).anyMatch(GLOBAL_AGGREGATOR_FACTORY_PREDICATE);
+    }
+
     /**
      * @return the number of sub-aggregator factories
      */
@@ -293,6 +339,8 @@ public int countAggregators() {
     /**
      * A mutable collection of {@link AggregationBuilder}s and
      * {@link PipelineAggregationBuilder}s.
+     *
+     * @opensearch.internal
      */
     public static class Builder implements Writeable, ToXContentObject {
         private final Set<String> names = new HashSet<>();
@@ -552,7 +600,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
         @Override
         public String toString() {
-            return Strings.toString(this, true, true);
+            return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
         }
 
         @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactory.java
index 65f44c8a34669..759d043743978 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/AggregatorFactory.java
@@ -40,6 +40,11 @@
 
 import static org.opensearch.search.aggregations.support.AggregationUsageService.OTHER_SUBTYPE;
 
+/**
+ * Base factory to instantiate an internal aggregator
+ *
+ * @opensearch.internal
+ */
 public abstract class AggregatorFactory {
     protected final String name;
     protected final AggregatorFactory parent;
@@ -109,4 +114,15 @@ public AggregatorFactory getParent() {
     public String getStatsSubtype() {
         return OTHER_SUBTYPE;
     }
+
+    /**
+     * Implementation should override this method and return true if the Aggregator created by the factory works with concurrent segment search execution model
+     */
+    protected boolean supportsConcurrentSegmentSearch() {
+        return false;
+    }
+
+    public boolean evaluateChildFactories() {
+        return factories.allFactoriesSupportConcurrentSearch();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/BaseAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/BaseAggregationBuilder.java
index 24b34c2c111c0..fe9f14c8a15a6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/BaseAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/BaseAggregationBuilder.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
 
 import java.util.Map;
@@ -40,6 +40,8 @@
 /**
  * Interface shared by {@link AggregationBuilder} and {@link PipelineAggregationBuilder} so they can conveniently share the same namespace
  * for {@link XContentParser#namedObject(Class, String, Object)}.
+ *
+ * @opensearch.internal
  */
 public interface BaseAggregationBuilder {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/BucketCollector.java b/server/src/main/java/org/opensearch/search/aggregations/BucketCollector.java
index e84f4d19e8080..5db683252a033 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/BucketCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/BucketCollector.java
@@ -40,6 +40,8 @@
 
 /**
  * A Collector that can collect data in separate buckets.
+ *
+ * @opensearch.internal
  */
 public abstract class BucketCollector implements Collector {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/BucketCollectorProcessor.java b/server/src/main/java/org/opensearch/search/aggregations/BucketCollectorProcessor.java
new file mode 100644
index 0000000000000..352ecf8bc94ad
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/BucketCollectorProcessor.java
@@ -0,0 +1,105 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.MultiCollector;
+import org.opensearch.common.lucene.MinimumScoreCollector;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.InternalProfileCollector;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * Processor to perform collector level processing specific to {@link BucketCollector} in different stages like: a) PostCollection
+ * after search on each leaf is completed and b) process the collectors to perform reduce after collection is completed
+ */
+public class BucketCollectorProcessor {
+
+    /**
+     * Performs {@link BucketCollector#postCollection()} on all the {@link BucketCollector} in the given {@link Collector} collector tree
+     * after the collection of documents on a leaf is completed. This method will be called by different slice threads on its own collector
+     * tree instance in case of concurrent segment search such that postCollection happens on the same slice thread which initialize and
+     * perform collection of the documents for a leaf segment. For sequential search case, there is always a single search thread which
+     * performs both collection and postCollection on {@link BucketCollector}.
+     * <p>
+     * This was originally done in {@link org.opensearch.search.aggregations.AggregationProcessor#postProcess(SearchContext)}. But with
+     * concurrent segment search path this needs to be performed here. There are AssertingCodecs in lucene which validates that the
+     * DocValues created for a field is always used by the same thread for a request. In concurrent segment search case, the DocValues
+     * gets initialized on different threads for different segments (or slices). Whereas the postProcess happens as part of reduce phase
+     * and is performed on the separate thread which is from search threadpool and not from slice threadpool. So two different threads
+     * performs the access on the DocValues causing the AssertingCodec to fail. From functionality perspective, there is no issue as
+     * DocValues for each segment is always accessed by a single thread at a time but those threads may be different (e.g. slice thread
+     * during collection and then search thread during reduce)
+     * </p>
+     * <p>
+     * NOTE: We can evaluate and deprecate this postCollection processing once lucene release the changes described in the
+     * <a href="https://github.com/apache/lucene/issues/12375">issue-12375</a>. With this new change we should be able to implement
+     * {@link BucketCollector#postCollection()} functionality using the lucene interface directly such that postCollection gets called
+     * from the slice thread by lucene itself
+     * </p>
+     * @param collectorTree collector tree used by calling thread
+     */
+    public void processPostCollection(Collector collectorTree) throws IOException {
+        final Queue<Collector> collectors = new LinkedList<>();
+        collectors.offer(collectorTree);
+        while (!collectors.isEmpty()) {
+            Collector currentCollector = collectors.poll();
+            if (currentCollector instanceof InternalProfileCollector) {
+                collectors.offer(((InternalProfileCollector) currentCollector).getCollector());
+            } else if (currentCollector instanceof MinimumScoreCollector) {
+                collectors.offer(((MinimumScoreCollector) currentCollector).getCollector());
+            } else if (currentCollector instanceof MultiCollector) {
+                for (Collector innerCollector : ((MultiCollector) currentCollector).getCollectors()) {
+                    collectors.offer(innerCollector);
+                }
+            } else if (currentCollector instanceof BucketCollector) {
+                ((BucketCollector) currentCollector).postCollection();
+            }
+        }
+    }
+
+    /**
+     * Unwraps the input collection of {@link Collector} to get the list of the {@link Aggregator} used by different slice threads. The
+     * input is expected to contain the collectors related to Aggregations only as that is passed to {@link AggregationCollectorManager}
+     * during the reduce phase. This list of {@link Aggregator} is used to create {@link InternalAggregation} and optionally perform
+     * reduce at shard level before returning response to coordinator
+     * @param collectors collection of aggregation collectors to reduce
+     * @return list of unwrapped {@link Aggregator}
+     */
+    public List<Aggregator> toAggregators(Collection<Collector> collectors) {
+        List<Aggregator> aggregators = new ArrayList<>();
+
+        final Deque<Collector> allCollectors = new LinkedList<>(collectors);
+        while (!allCollectors.isEmpty()) {
+            final Collector currentCollector = allCollectors.pop();
+            if (currentCollector instanceof Aggregator) {
+                aggregators.add((Aggregator) currentCollector);
+            } else if (currentCollector instanceof InternalProfileCollector) {
+                if (((InternalProfileCollector) currentCollector).getCollector() instanceof Aggregator) {
+                    aggregators.add((Aggregator) ((InternalProfileCollector) currentCollector).getCollector());
+                } else if (((InternalProfileCollector) currentCollector).getCollector() instanceof MultiBucketCollector) {
+                    allCollectors.addAll(
+                        Arrays.asList(((MultiBucketCollector) ((InternalProfileCollector) currentCollector).getCollector()).getCollectors())
+                    );
+                }
+            } else if (currentCollector instanceof MultiBucketCollector) {
+                allCollectors.addAll(Arrays.asList(((MultiBucketCollector) currentCollector).getCollectors()));
+            }
+        }
+        return aggregators;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/BucketOrder.java b/server/src/main/java/org/opensearch/search/aggregations/BucketOrder.java
index 423c143e6aaea..56f3820a60348 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/BucketOrder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/BucketOrder.java
@@ -31,10 +31,11 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation.Bucket;
 import org.opensearch.search.aggregations.support.AggregationPath;
 
@@ -49,6 +50,8 @@
  * "complete" buckets using {@link #comparator()} or against a combination
  * of the buckets internals with its ordinal with
  * {@link #partiallyBuiltBucketComparator(ToLongFunction, Aggregator)}.
+ *
+ * @opensearch.internal
  */
 public abstract class BucketOrder implements ToXContentObject, Writeable {
     /**
@@ -169,6 +172,6 @@ public void writeTo(StreamOutput out) throws IOException {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/CardinalityUpperBound.java b/server/src/main/java/org/opensearch/search/aggregations/CardinalityUpperBound.java
index 984c8a0872903..15beeac82930a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/CardinalityUpperBound.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/CardinalityUpperBound.java
@@ -41,6 +41,8 @@
 /**
  * Upper bound of how many {@code owningBucketOrds} that an {@link Aggregator}
  * will have to collect into.
+ *
+ * @opensearch.internal
  */
 public abstract class CardinalityUpperBound {
     /**
@@ -111,6 +113,8 @@ private CardinalityUpperBound() {
 
     /**
      * Cardinality estimate with a known upper bound.
+     *
+     * @opensearch.internal
      */
     private static class KnownCardinalityUpperBound extends CardinalityUpperBound {
         private final int estimate;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/ConcurrentAggregationProcessor.java b/server/src/main/java/org/opensearch/search/aggregations/ConcurrentAggregationProcessor.java
new file mode 100644
index 0000000000000..fbeb583984ac5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/ConcurrentAggregationProcessor.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.Query;
+import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.InternalProfileCollectorManager;
+import org.opensearch.search.profile.query.InternalProfileComponent;
+import org.opensearch.search.query.QueryPhaseExecutionException;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+import java.util.Collections;
+
+/**
+ * {@link AggregationProcessor} implementation to be used with {@link org.opensearch.search.query.ConcurrentQueryPhaseSearcher}. It takes
+ * care of performing shard level reduce on Aggregation results collected as part of concurrent execution among slices. This is done to
+ * avoid the increase in aggregation result sets returned by each shard to coordinator where final reduce happens for results received from
+ * all the shards
+ */
+public class ConcurrentAggregationProcessor implements AggregationProcessor {
+
+    private final BucketCollectorProcessor bucketCollectorProcessor = new BucketCollectorProcessor();
+
+    @Override
+    public void preProcess(SearchContext context) {
+        try {
+            if (context.aggregations() != null) {
+                // update the bucket collector process as there is aggregation in the request
+                context.setBucketCollectorProcessor(bucketCollectorProcessor);
+                if (context.aggregations().factories().hasNonGlobalAggregator()) {
+                    context.queryCollectorManagers().put(NonGlobalAggCollectorManager.class, new NonGlobalAggCollectorManager(context));
+                }
+                // initialize global aggregators as well, such that any failure to initialize can be caught before executing the request
+                if (context.aggregations().factories().hasGlobalAggregator()) {
+                    context.queryCollectorManagers().put(GlobalAggCollectorManager.class, new GlobalAggCollectorManager(context));
+                }
+            }
+        } catch (IOException ex) {
+            throw new AggregationInitializationException("Could not initialize aggregators", ex);
+        }
+    }
+
+    @Override
+    public void postProcess(SearchContext context) {
+        if (context.aggregations() == null) {
+            context.queryResult().aggregations(null);
+            return;
+        }
+
+        // for concurrent case we will perform only global aggregation in post process as QueryResult is already populated with results of
+        // processing the non-global aggregation
+        CollectorManager<? extends Collector, ReduceableSearchResult> globalCollectorManager = context.queryCollectorManagers()
+            .get(GlobalAggCollectorManager.class);
+        try {
+            if (globalCollectorManager != null) {
+                Query query = context.buildFilteredQuery(Queries.newMatchAllQuery());
+                if (context.getProfilers() != null) {
+                    globalCollectorManager = new InternalProfileCollectorManager(
+                        globalCollectorManager,
+                        ((AggregationCollectorManager) globalCollectorManager).getCollectorReason(),
+                        Collections.emptyList()
+                    );
+                    context.getProfilers().addQueryProfiler().setCollector((InternalProfileComponent) globalCollectorManager);
+                }
+                final ReduceableSearchResult result = context.searcher().search(query, globalCollectorManager);
+                result.reduce(context.queryResult());
+            }
+        } catch (Exception e) {
+            throw new QueryPhaseExecutionException(context.shardTarget(), "Failed to execute global aggregators", e);
+        }
+
+        // disable aggregations so that they don't run on next pages in case of scrolling
+        context.aggregations(null);
+        context.queryCollectorManagers().remove(NonGlobalAggCollectorManager.class);
+        context.queryCollectorManagers().remove(GlobalAggCollectorManager.class);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/DefaultAggregationProcessor.java b/server/src/main/java/org/opensearch/search/aggregations/DefaultAggregationProcessor.java
new file mode 100644
index 0000000000000..c674f4b9b673a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/DefaultAggregationProcessor.java
@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Query;
+import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.InternalProfileCollector;
+import org.opensearch.search.query.QueryPhaseExecutionException;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * {@link AggregationProcessor} implementation which is used with {@link org.opensearch.search.query.QueryPhase.DefaultQueryPhaseSearcher}.
+ * This is the default implementation which works when collection for aggregations happen in sequential manner. It doesn't perform any
+ * reduce on the collected documents at shard level
+ */
+public class DefaultAggregationProcessor implements AggregationProcessor {
+
+    private final BucketCollectorProcessor bucketCollectorProcessor = new BucketCollectorProcessor();
+
+    @Override
+    public void preProcess(SearchContext context) {
+        try {
+            if (context.aggregations() != null) {
+                // update the bucket collector process as there is aggregation in the request
+                context.setBucketCollectorProcessor(bucketCollectorProcessor);
+                if (context.aggregations().factories().hasNonGlobalAggregator()) {
+                    context.queryCollectorManagers()
+                        .put(NonGlobalAggCollectorManager.class, new NonGlobalAggCollectorManagerWithSingleCollector(context));
+                }
+                // initialize global aggregators as well, such that any failure to initialize can be caught before executing the request
+                if (context.aggregations().factories().hasGlobalAggregator()) {
+                    context.queryCollectorManagers()
+                        .put(GlobalAggCollectorManager.class, new GlobalAggCollectorManagerWithSingleCollector(context));
+                }
+            }
+        } catch (IOException ex) {
+            throw new AggregationInitializationException("Could not initialize aggregators", ex);
+        }
+    }
+
+    @Override
+    public void postProcess(SearchContext context) {
+        if (context.aggregations() == null) {
+            context.queryResult().aggregations(null);
+            return;
+        }
+
+        if (context.queryResult().hasAggs()) {
+            // no need to compute the aggs twice, they should be computed on a per context basis
+            return;
+        }
+
+        final AggregationCollectorManager nonGlobalCollectorManager = (AggregationCollectorManager) context.queryCollectorManagers()
+            .get(NonGlobalAggCollectorManager.class);
+        final AggregationCollectorManager globalCollectorManager = (AggregationCollectorManager) context.queryCollectorManagers()
+            .get(GlobalAggCollectorManager.class);
+        try {
+            if (nonGlobalCollectorManager != null) {
+                nonGlobalCollectorManager.reduce(List.of()).reduce(context.queryResult());
+            }
+
+            try {
+                if (globalCollectorManager != null) {
+                    Query query = context.buildFilteredQuery(Queries.newMatchAllQuery());
+                    if (context.getProfilers() != null) {
+                        context.getProfilers()
+                            .addQueryProfiler()
+                            .setCollector(
+                                new InternalProfileCollector(
+                                    globalCollectorManager.newCollector(),
+                                    globalCollectorManager.getCollectorReason(),
+                                    Collections.emptyList()
+                                )
+                            );
+                    }
+                    context.searcher().search(query, globalCollectorManager.newCollector());
+                    globalCollectorManager.reduce(List.of()).reduce(context.queryResult());
+                }
+            } catch (Exception e) {
+                throw new QueryPhaseExecutionException(context.shardTarget(), "Failed to execute global aggregators", e);
+            }
+        } catch (IOException ex) {
+            throw new QueryPhaseExecutionException(context.shardTarget(), "Post processing failed for aggregators", ex);
+        }
+
+        // disable aggregations so that they don't run on next pages in case of scrolling
+        context.aggregations(null);
+        context.queryCollectorManagers().remove(NonGlobalAggCollectorManager.class);
+        context.queryCollectorManagers().remove(GlobalAggCollectorManager.class);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManager.java b/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManager.java
new file mode 100644
index 0000000000000..711e87d6f4fdb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManager.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.CollectorResult;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Objects;
+
+/**
+ * {@link CollectorManager} to take care of global aggregation operators in case of concurrent segment search
+ */
+public class GlobalAggCollectorManager extends AggregationCollectorManager {
+
+    private Collector collector;
+    private final String collectorName;
+
+    public GlobalAggCollectorManager(SearchContext context) throws IOException {
+        super(context, context.aggregations().factories()::createTopLevelGlobalAggregators, CollectorResult.REASON_AGGREGATION_GLOBAL);
+        collector = Objects.requireNonNull(super.newCollector(), "collector instance is null");
+        collectorName = collector.toString();
+    }
+
+    @Override
+    public Collector newCollector() throws IOException {
+        if (collector != null) {
+            final Collector toReturn = collector;
+            collector = null;
+            return toReturn;
+        } else {
+            return super.newCollector();
+        }
+    }
+
+    @Override
+    protected AggregationReduceableSearchResult buildAggregationResult(InternalAggregations internalAggregations) {
+        // Reduce the aggregations across slices before sending to the coordinator. We will perform shard level reduce as long as any slices
+        // were created so that we can apply shard level bucket count thresholds in the reduce phase.
+        return new AggregationReduceableSearchResult(
+            // using topLevelReduce here as PipelineTreeSource needs to be sent to coordinator in older release of OpenSearch. The actual
+            // evaluation of pipeline aggregation though happens on the coordinator during final reduction phase
+            InternalAggregations.topLevelReduce(Collections.singletonList(internalAggregations), context.partialOnShard())
+        );
+    }
+
+    @Override
+    public String getCollectorName() {
+        return collectorName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManagerWithSingleCollector.java b/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManagerWithSingleCollector.java
new file mode 100644
index 0000000000000..973749c0d5189
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/GlobalAggCollectorManagerWithSingleCollector.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.CollectorResult;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * {@link CollectorManager} to take care of global aggregation operators in case of non-concurrent segment search. This CollectorManager
+ * returns the same collector instance (i.e. created in constructor of super class) on each newCollector call
+ */
+public class GlobalAggCollectorManagerWithSingleCollector extends AggregationCollectorManager {
+
+    private final Collector collector;
+    private final String collectorName;
+
+    public GlobalAggCollectorManagerWithSingleCollector(SearchContext context) throws IOException {
+        super(context, context.aggregations().factories()::createTopLevelGlobalAggregators, CollectorResult.REASON_AGGREGATION_GLOBAL);
+        collector = Objects.requireNonNull(super.newCollector(), "collector instance is null");
+        collectorName = collector.toString();
+    }
+
+    @Override
+    public Collector newCollector() throws IOException {
+        return collector;
+    }
+
+    @Override
+    public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+        assert collectors.isEmpty() : "Reduce on GlobalAggregationCollectorManagerWithCollector called with non-empty collectors";
+        return super.reduce(List.of(collector));
+    }
+
+    @Override
+    public String getCollectorName() {
+        return collectorName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/HasAggregations.java b/server/src/main/java/org/opensearch/search/aggregations/HasAggregations.java
index 92b4d3f69bb6f..6d3c599eee05c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/HasAggregations.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/HasAggregations.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.search.aggregations;
 
+/**
+ * Base interface for buckets that have sub aggs
+ *
+ * @opensearch.internal
+ */
 public interface HasAggregations {
 
     Aggregations getAggregations();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/InternalAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/InternalAggregation.java
index 7c403bcb9dbbf..211d3b7f9c1f6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/InternalAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/InternalAggregation.java
@@ -32,14 +32,17 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.script.ScriptService;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator.PipelineTree;
 import org.opensearch.search.aggregations.support.AggregationPath;
@@ -58,10 +61,14 @@
 
 /**
  * An internal implementation of {@link Aggregation}. Serves as a base class for all aggregation implementations.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalAggregation implements Aggregation, NamedWriteable {
     /**
      * Builds {@link ReduceContext}.
+     *
+     * @opensearch.internal
      */
     public interface ReduceContextBuilder {
         /**
@@ -75,11 +82,18 @@ public interface ReduceContextBuilder {
         ReduceContext forFinalReduction();
     }
 
+    /**
+     * The reduce context
+     *
+     * @opensearch.internal
+     */
     public static class ReduceContext {
         private final BigArrays bigArrays;
         private final ScriptService scriptService;
         private final IntConsumer multiBucketConsumer;
         private final PipelineTree pipelineTreeRoot;
+
+        private boolean isSliceLevel;
         /**
          * Supplies the pipelines when the result of the reduce is serialized
          * to node versions that need pipeline aggregators to be serialized
@@ -129,6 +143,7 @@ private ReduceContext(
             this.multiBucketConsumer = multiBucketConsumer;
             this.pipelineTreeRoot = pipelineTreeRoot;
             this.pipelineTreeForBwcSerialization = pipelineTreeForBwcSerialization;
+            this.isSliceLevel = false;
         }
 
         /**
@@ -140,6 +155,26 @@ public boolean isFinalReduce() {
             return pipelineTreeRoot != null;
         }
 
+        public void setSliceLevel(boolean sliceLevel) {
+            this.isSliceLevel = sliceLevel;
+        }
+
+        public boolean isSliceLevel() {
+            return this.isSliceLevel;
+        }
+
+        /**
+         * For slice level partial reduce we will apply shard level `shard_size` and `shard_min_doc_count` limits
+         * whereas for coordinator level partial reduce it will use top level `size` and `min_doc_count`
+         */
+        public LocalBucketCountThresholds asLocalBucketCountThresholds(TermsAggregator.BucketCountThresholds bucketCountThresholds) {
+            if (isSliceLevel()) {
+                return new LocalBucketCountThresholds(bucketCountThresholds.getShardMinDocCount(), bucketCountThresholds.getShardSize());
+            } else {
+                return new LocalBucketCountThresholds(bucketCountThresholds.getMinDocCount(), bucketCountThresholds.getRequiredSize());
+            }
+        }
+
         public BigArrays bigArrays() {
             return bigArrays;
         }
@@ -399,7 +434,7 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/InternalAggregations.java b/server/src/main/java/org/opensearch/search/aggregations/InternalAggregations.java
index 371a2b04ae019..12a859e7c33e4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/InternalAggregations.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/InternalAggregations.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator.PipelineTree;
@@ -59,6 +59,8 @@
 
 /**
  * An internal implementation of {@link Aggregations}.
+ *
+ * @opensearch.internal
  */
 public final class InternalAggregations extends Aggregations implements Writeable {
 
@@ -99,6 +101,18 @@ public InternalAggregations(List<InternalAggregation> aggregations, Supplier<Pip
         this.pipelineTreeForBwcSerialization = pipelineTreeSource;
     }
 
+    /**
+     * Constructs a node in the aggregation tree. This constructor is used to add pipelineTreeSource in new InternalAggregations object with
+     * provided list of InternalAggregation from passed in InternalAggregations.
+     *
+     * @param pipelineTreeSource must be null inside the tree or after final reduction. Should reference the
+     *                           search request otherwise so we can properly serialize the response to
+     *                           versions of OpenSearch that require the pipelines to be serialized.
+     */
+    public InternalAggregations(InternalAggregations aggregations, Supplier<PipelineAggregator.PipelineTree> pipelineTreeSource) {
+        this(aggregations.getInternalAggregations(), pipelineTreeSource);
+    }
+
     public static InternalAggregations from(List<InternalAggregation> aggregations) {
         if (aggregations.isEmpty()) {
             return EMPTY;
@@ -302,6 +316,20 @@ public long getSerializedSize() {
         }
     }
 
+    public static InternalAggregations merge(InternalAggregations first, InternalAggregations second) {
+        final List<InternalAggregation> fromFirst = first.getInternalAggregations();
+        final List<InternalAggregation> fromSecond = second.getInternalAggregations();
+        final List<InternalAggregation> mergedAggregation = new ArrayList<>(fromFirst.size() + fromSecond.size());
+        mergedAggregation.addAll(fromFirst);
+        mergedAggregation.addAll(fromSecond);
+        return new InternalAggregations(mergedAggregation, first.getPipelineTreeForBwcSerialization());
+    }
+
+    /**
+     * A counting stream output
+     *
+     * @opensearch.internal
+     */
     private static class CountingStreamOutput extends StreamOutput {
         long size = 0;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/InternalMultiBucketAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/InternalMultiBucketAggregation.java
index 983f2cbe21ae1..1d9df65fee92d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/InternalMultiBucketAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/InternalMultiBucketAggregation.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 import org.opensearch.search.aggregations.bucket.SingleBucketAggregation;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator.PipelineTree;
@@ -45,6 +45,11 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+/**
+ * Base class for internal aggregations that are comprised of multiple buckets
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalMultiBucketAggregation<
     A extends InternalMultiBucketAggregation,
     B extends InternalMultiBucketAggregation.InternalBucket> extends InternalAggregation implements MultiBucketsAggregation {
@@ -218,6 +223,11 @@ private List<B> reducePipelineBuckets(ReduceContext reduceContext, PipelineTree
         return reducedBuckets;
     }
 
+    /**
+     * An internal buck for the internal multibucket agg
+     *
+     * @opensearch.internal
+     */
     public abstract static class InternalBucket implements Bucket, Writeable {
 
         public Object getProperty(String containingAggName, List<String> path) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/InternalOrder.java b/server/src/main/java/org/opensearch/search/aggregations/InternalOrder.java
index 923650fbeac3f..13d0abd0176df 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/InternalOrder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/InternalOrder.java
@@ -31,14 +31,14 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.util.Comparators;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.Aggregator.BucketComparator;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation.Bucket;
 import org.opensearch.search.aggregations.support.AggregationPath;
@@ -58,11 +58,15 @@
 
 /**
  * Implementations for {@link Bucket} ordering strategies.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalOrder extends BucketOrder {
     // TODO merge the contents of this file into BucketOrder. The way it is now is relic.
     /**
      * {@link Bucket} ordering strategy to sort by a sub-aggregation.
+     *
+     * @opensearch.internal
      */
     public static class Aggregation extends InternalOrder {
         static final byte ID = 0;
@@ -131,6 +135,8 @@ public boolean equals(Object obj) {
 
     /**
      * {@link Bucket} ordering strategy to sort by multiple criteria.
+     *
+     * @opensearch.internal
      */
     public static class CompoundOrder extends BucketOrder {
 
@@ -242,6 +248,8 @@ public boolean equals(Object obj) {
      * {@link BucketOrder} implementation for simple, fixed orders like
      * {@link InternalOrder#COUNT_ASC}. Complex implementations should not
      * use this.
+     *
+     * @opensearch.internal
      */
     private static class SimpleOrder extends InternalOrder {
         private final byte id;
@@ -403,6 +411,8 @@ private static boolean isOrder(BucketOrder order, BucketOrder expected) {
 
     /**
      * Contains logic for reading/writing {@link BucketOrder} from/to streams.
+     *
+     * @opensearch.internal
      */
     public static class Streams {
 
@@ -491,6 +501,8 @@ public static void writeHistogramOrder(BucketOrder order, StreamOutput out, bool
 
     /**
      * Contains logic for parsing a {@link BucketOrder} from a {@link XContentParser}.
+     *
+     * @opensearch.internal
      */
     public static class Parser {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/InvalidAggregationPathException.java b/server/src/main/java/org/opensearch/search/aggregations/InvalidAggregationPathException.java
index 011206ddd049d..08ea0553affd1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/InvalidAggregationPathException.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/InvalidAggregationPathException.java
@@ -33,10 +33,15 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Error thrown when an invalid agg is called
+ *
+ * @opensearch.internal
+ */
 public class InvalidAggregationPathException extends OpenSearchException {
 
     public InvalidAggregationPathException(String msg) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/KeyComparable.java b/server/src/main/java/org/opensearch/search/aggregations/KeyComparable.java
index 1e64ad8992a27..5acf32183a810 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/KeyComparable.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/KeyComparable.java
@@ -39,6 +39,8 @@
  *
  * @param <T> {@link Bucket} of the same type that also implements {@link KeyComparable}.
  * @see BucketOrder#key(boolean)
+ *
+ * @opensearch.internal
  */
 public interface KeyComparable<T extends Bucket & KeyComparable<T>> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollector.java b/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollector.java
index 0d29469f12d97..6694ba3e0a34d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollector.java
@@ -42,6 +42,8 @@
 
 /**
  * Per-leaf bucket collector.
+ *
+ * @opensearch.internal
  */
 public abstract class LeafBucketCollector implements LeafCollector {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollectorBase.java b/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollectorBase.java
index 2da9f4307c40a..5b5f2b7a6f8cb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollectorBase.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/LeafBucketCollectorBase.java
@@ -41,6 +41,8 @@
  * A {@link LeafBucketCollector} that delegates all calls to the sub leaf
  * aggregator and sets the scorer on its source of values if it implements
  * {@link ScorerAware}.
+ *
+ * @opensearch.internal
  */
 public class LeafBucketCollectorBase extends LeafBucketCollector {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/MultiBucketCollector.java b/server/src/main/java/org/opensearch/search/aggregations/MultiBucketCollector.java
index 6bb044b1d7ea8..8aad9db0248f1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/MultiBucketCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/MultiBucketCollector.java
@@ -51,6 +51,8 @@
  * {@link BucketCollector}s. It is similar to the {@link MultiCollector} except that the
  * {@link #wrap} method filters out the {@link BucketCollector#NO_OP_COLLECTOR}s and not
  * the null ones.
+ *
+ * @opensearch.internal
  */
 public class MultiBucketCollector extends BucketCollector {
 
@@ -119,6 +121,10 @@ private MultiBucketCollector(BucketCollector... collectors) {
         this.cacheScores = numNeedsScores >= 2;
     }
 
+    public BucketCollector[] getCollectors() {
+        return collectors;
+    }
+
     @Override
     public ScoreMode scoreMode() {
         ScoreMode scoreMode = null;
@@ -174,6 +180,11 @@ public LeafBucketCollector getLeafCollector(LeafReaderContext context) throws IO
         }
     }
 
+    /**
+     * A multi leaf bucket collector
+     *
+     * @opensearch.internal
+     */
     private static class MultiLeafBucketCollector extends LeafBucketCollector {
 
         private final boolean cacheScores;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/MultiBucketConsumerService.java b/server/src/main/java/org/opensearch/search/aggregations/MultiBucketConsumerService.java
index ce9527e812db5..5bd36d0255b91 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/MultiBucketConsumerService.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/MultiBucketConsumerService.java
@@ -32,16 +32,18 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.bucket.BucketsAggregator;
 
 import java.io.IOException;
+import java.util.concurrent.atomic.LongAdder;
 import java.util.function.IntConsumer;
 
 /**
@@ -49,6 +51,8 @@
  * The consumer is used by {@link BucketsAggregator} and {@link InternalMultiBucketAggregation} to limit the number of buckets created
  * in {@link Aggregator#buildAggregations} and {@link InternalAggregation#reduce}.
  * The limit can be set by changing the `search.max_buckets` cluster setting and defaults to 65535.
+ *
+ * @opensearch.internal
  */
 public class MultiBucketConsumerService {
     public static final int DEFAULT_MAX_BUCKETS = 65535;
@@ -74,6 +78,11 @@ private void setMaxBucket(int maxBucket) {
         this.maxBucket = maxBucket;
     }
 
+    /**
+     * Thrown when there are too many buckets
+     *
+     * @opensearch.internal
+     */
     public static class TooManyBucketsException extends AggregationExecutionException {
         private final int maxBuckets;
 
@@ -113,18 +122,43 @@ protected void metadataToXContent(XContentBuilder builder, Params params) throws
      * when the sum of the provided values is above the limit (`search.max_buckets`).
      * It is used by aggregators to limit the number of bucket creation during
      * {@link Aggregator#buildAggregations} and {@link InternalAggregation#reduce}.
+     *
+     * @opensearch.internal
      */
     public static class MultiBucketConsumer implements IntConsumer {
         private final int limit;
         private final CircuitBreaker breaker;
 
-        // aggregations execute in a single thread so no atomic here
+        // aggregations execute in a single thread for both sequential
+        // and concurrent search, so no atomic here
         private int count;
-        private int callCount = 0;
+
+        // will be updated by multiple threads in concurrent search
+        // hence making it as LongAdder
+        private final LongAdder callCount;
+        private volatile boolean circuitBreakerTripped;
+        private final int availProcessors;
 
         public MultiBucketConsumer(int limit, CircuitBreaker breaker) {
             this.limit = limit;
             this.breaker = breaker;
+            callCount = new LongAdder();
+            availProcessors = Runtime.getRuntime().availableProcessors();
+        }
+
+        // only visible for testing
+        protected MultiBucketConsumer(
+            int limit,
+            CircuitBreaker breaker,
+            LongAdder callCount,
+            boolean circuitBreakerTripped,
+            int availProcessors
+        ) {
+            this.limit = limit;
+            this.breaker = breaker;
+            this.callCount = callCount;
+            this.circuitBreakerTripped = circuitBreakerTripped;
+            this.availProcessors = availProcessors;
         }
 
         @Override
@@ -144,10 +178,27 @@ public void accept(int value) {
                     );
                 }
             }
-            // check parent circuit breaker every 1024 calls
-            callCount++;
-            if ((callCount & 0x3FF) == 0) {
-                breaker.addEstimateBytesAndMaybeBreak(0, "allocated_buckets");
+            callCount.increment();
+            // tripping the circuit breaker for other threads in case of concurrent search
+            // if the circuit breaker has tripped for one of the threads already, more info
+            // can be found on: https://github.com/opensearch-project/OpenSearch/issues/7785
+            if (circuitBreakerTripped) {
+                throw new CircuitBreakingException(
+                    "Circuit breaker for this consumer has already been tripped by previous invocations. "
+                        + "This can happen in case of concurrent segment search when multiple threads are "
+                        + "executing the request and one of the thread has already tripped the circuit breaker",
+                    breaker.getDurability()
+                );
+            }
+            // check parent circuit breaker every 1024 to (1024 + available processors) calls
+            long sum = callCount.sum();
+            if ((sum >= 1024) && (sum & 0x3FF) <= availProcessors) {
+                try {
+                    breaker.addEstimateBytesAndMaybeBreak(0, "allocated_buckets");
+                } catch (CircuitBreakingException e) {
+                    circuitBreakerTripped = true;
+                    throw e;
+                }
             }
         }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/NonCollectingAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/NonCollectingAggregator.java
index 92a37b726469b..34d1d48d8ce21 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/NonCollectingAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/NonCollectingAggregator.java
@@ -41,6 +41,8 @@
 /**
  * An aggregator that is not collected, this can typically be used when running an aggregation over a field that doesn't have
  * a mapping.
+ *
+ * @opensearch.internal
  */
 public abstract class NonCollectingAggregator extends AggregatorBase {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManager.java b/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManager.java
new file mode 100644
index 0000000000000..d90a6d8bf2cc9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManager.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.CollectorResult;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Objects;
+
+/**
+ * {@link CollectorManager} to take care of non-global aggregation operators in case of concurrent segment search
+ */
+public class NonGlobalAggCollectorManager extends AggregationCollectorManager {
+
+    private Collector collector;
+    private final String collectorName;
+
+    public NonGlobalAggCollectorManager(SearchContext context) throws IOException {
+        super(context, context.aggregations().factories()::createTopLevelNonGlobalAggregators, CollectorResult.REASON_AGGREGATION);
+        collector = Objects.requireNonNull(super.newCollector(), "collector instance is null");
+        collectorName = collector.toString();
+    }
+
+    @Override
+    public Collector newCollector() throws IOException {
+        if (collector != null) {
+            final Collector toReturn = collector;
+            collector = null;
+            return toReturn;
+        } else {
+            return super.newCollector();
+        }
+    }
+
+    @Override
+    protected AggregationReduceableSearchResult buildAggregationResult(InternalAggregations internalAggregations) {
+        // Reduce the aggregations across slices before sending to the coordinator. We will perform shard level reduce as long as any slices
+        // were created so that we can apply shard level bucket count thresholds in the reduce phase.
+        return new AggregationReduceableSearchResult(
+            // using topLevelReduce here as PipelineTreeSource needs to be sent to coordinator in older release of OpenSearch. The actual
+            // evaluation of pipeline aggregation though happens on the coordinator during final reduction phase
+            InternalAggregations.topLevelReduce(Collections.singletonList(internalAggregations), context.partialOnShard())
+        );
+    }
+
+    @Override
+    public String getCollectorName() {
+        return collectorName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManagerWithSingleCollector.java b/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManagerWithSingleCollector.java
new file mode 100644
index 0000000000000..a6eb00f2d70f7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/NonGlobalAggCollectorManagerWithSingleCollector.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.CollectorResult;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * {@link CollectorManager} to take care of non-global aggregation operators in case of non-concurrent segment search. This
+ * CollectorManager returns the same collector instance (i.e. created in constructor of super class) on each newCollector call
+ */
+public class NonGlobalAggCollectorManagerWithSingleCollector extends AggregationCollectorManager {
+
+    private final Collector collector;
+    private final String collectorName;
+
+    public NonGlobalAggCollectorManagerWithSingleCollector(SearchContext context) throws IOException {
+        super(context, context.aggregations().factories()::createTopLevelNonGlobalAggregators, CollectorResult.REASON_AGGREGATION);
+        collector = Objects.requireNonNull(super.newCollector(), "collector instance is null");
+        collectorName = collector.toString();
+    }
+
+    @Override
+    public Collector newCollector() throws IOException {
+        return collector;
+    }
+
+    @Override
+    public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+        assert collectors.isEmpty() : "Reduce on NonGlobalAggregationCollectorManagerWithCollector called with non-empty collectors";
+        return super.reduce(List.of(collector));
+    }
+
+    @Override
+    public String getCollectorName() {
+        return collectorName;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/ParsedAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/ParsedAggregation.java
index 64d2779dceb61..e173704d36ce7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/ParsedAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/ParsedAggregation.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.xcontent.AbstractObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -46,6 +46,8 @@
 /**
  * An implementation of {@link Aggregation} that is parsed from a REST response.
  * Serves as a base class for all aggregation implementations that are parsed from REST.
+ *
+ * @opensearch.internal
  */
 public abstract class ParsedAggregation implements Aggregation, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/ParsedMultiBucketAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/ParsedMultiBucketAggregation.java
index 67310bc2a5ae2..5cbe0c9f3eeee 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/ParsedMultiBucketAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/ParsedMultiBucketAggregation.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 
 import java.io.IOException;
@@ -45,8 +45,13 @@
 import java.util.List;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * A multi-bucket agg that has been parsed
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedMultiBucketAggregation<B extends ParsedMultiBucketAggregation.Bucket> extends ParsedAggregation
     implements
         MultiBucketsAggregation {
@@ -94,6 +99,11 @@ protected static void declareMultiBucketAggregationFields(
         }, CommonFields.BUCKETS, ObjectParser.ValueType.OBJECT_ARRAY);
     }
 
+    /**
+     * A parsed bucket
+     *
+     * @opensearch.internal
+     */
     public abstract static class ParsedBucket implements MultiBucketsAggregation.Bucket {
 
         private Aggregations aggregations;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregationBuilder.java
index 3652f46350985..9754498841159 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregationBuilder.java
@@ -33,9 +33,10 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.ValidateActions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.Rewriteable;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
@@ -52,6 +53,8 @@
 /**
  * A factory that knows how to create an {@link PipelineAggregator} of a
  * specific type.
+ *
+ * @opensearch.internal
  */
 public abstract class PipelineAggregationBuilder
     implements
@@ -95,6 +98,11 @@ public final String[] getBucketsPaths() {
      */
     protected abstract void validate(ValidationContext context);
 
+    /**
+     * The context used for validation
+     *
+     * @opensearch.internal
+     */
     public abstract static class ValidationContext {
         /**
          * Build the context for the root of the aggregation tree.
@@ -120,6 +128,11 @@ private ValidationContext(ActionRequestValidationException validationFailuresSoF
             this.e = validationFailuresSoFar;
         }
 
+        /**
+         * The root of the tree
+         *
+         * @opensearch.internal
+         */
         private static class ForTreeRoot extends ValidationContext {
             private final Collection<AggregationBuilder> siblingAggregations;
             private final Collection<PipelineAggregationBuilder> siblingPipelineAggregations;
@@ -160,6 +173,11 @@ public void validateParentAggSequentiallyOrdered(String type, String name) {
             }
         }
 
+        /**
+         * The internal tree node
+         *
+         * @opensearch.internal
+         */
         private static class ForInsideTree extends ValidationContext {
             private final AggregationBuilder parent;
 
@@ -270,7 +288,7 @@ public PipelineAggregationBuilder subAggregations(Builder subFactories) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregatorBuilders.java b/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregatorBuilders.java
index 3e8d3325fd604..b025860b9e65b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregatorBuilders.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/PipelineAggregatorBuilders.java
@@ -53,6 +53,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Builder utility class for pipeline aggs
+ *
+ * @opensearch.internal
+ */
 public final class PipelineAggregatorBuilders {
 
     private PipelineAggregatorBuilders() {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/SearchContextAggregations.java b/server/src/main/java/org/opensearch/search/aggregations/SearchContextAggregations.java
index 229f6bf118f61..16339713dc83e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/SearchContextAggregations.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/SearchContextAggregations.java
@@ -35,12 +35,12 @@
 
 /**
  * The aggregation context that is part of the search context.
+ *
+ * @opensearch.internal
  */
 public class SearchContextAggregations {
-
     private final AggregatorFactories factories;
     private final MultiBucketConsumer multiBucketConsumer;
-    private Aggregator[] aggregators;
 
     /**
      * Creates a new aggregation context with the parsed aggregator factories
@@ -54,19 +54,6 @@ public AggregatorFactories factories() {
         return factories;
     }
 
-    public Aggregator[] aggregators() {
-        return aggregators;
-    }
-
-    /**
-     * Registers all the created aggregators (top level aggregators) for the search execution context.
-     *
-     * @param aggregators The top level aggregators of the search execution.
-     */
-    public void aggregators(Aggregator[] aggregators) {
-        this.aggregators = aggregators;
-    }
-
     /**
      * Returns a consumer for multi bucket aggregation that checks the total number of buckets
      * created in the response
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollector.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollector.java
index 48e674d977231..2e7c4659bcb00 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollector.java
@@ -61,8 +61,15 @@
  * matches and then is able to replay a given subset of buckets which represent
  * the survivors from a pruning process performed by the aggregator that owns
  * this collector.
+ *
+ * @opensearch.internal
  */
 public class BestBucketsDeferringCollector extends DeferringBucketCollector {
+    /**
+     * Entry in the bucket collector
+     *
+     * @opensearch.internal
+     */
     static class Entry {
         final LeafReaderContext context;
         final PackedLongValues docDeltas;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketUtils.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketUtils.java
index 6dd064a501087..9a4f19910b36c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketUtils.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketUtils.java
@@ -33,6 +33,8 @@
 
 /**
  * Helper functions for common Bucketing functions
+ *
+ * @opensearch.internal
  */
 public final class BucketUtils {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketsAggregator.java
index f18f6fb83816d..67af0b13eed3b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/BucketsAggregator.java
@@ -31,9 +31,10 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.IntArray;
+import org.opensearch.common.util.LongArray;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorBase;
@@ -61,11 +62,17 @@
 import java.util.function.LongUnaryOperator;
 import java.util.function.ToLongFunction;
 
+/**
+ * Base class to collect all docs into buckets
+ *
+ * @opensearch.internal
+ */
 public abstract class BucketsAggregator extends AggregatorBase {
 
     private final BigArrays bigArrays;
     private final IntConsumer multiBucketConsumer;
-    private IntArray docCounts;
+    private LongArray docCounts;
+    protected final DocCountProvider docCountProvider;
 
     public BucketsAggregator(
         String name,
@@ -82,7 +89,8 @@ public BucketsAggregator(
         } else {
             multiBucketConsumer = (count) -> {};
         }
-        docCounts = bigArrays.newIntArray(1, true);
+        docCounts = bigArrays.newLongArray(1, true);
+        docCountProvider = new DocCountProvider();
     }
 
     /**
@@ -111,7 +119,8 @@ public final void collectBucket(LeafBucketCollector subCollector, int doc, long
      * Same as {@link #collectBucket(LeafBucketCollector, int, long)}, but doesn't check if the docCounts needs to be re-sized.
      */
     public final void collectExistingBucket(LeafBucketCollector subCollector, int doc, long bucketOrd) throws IOException {
-        if (docCounts.increment(bucketOrd, 1) == 1) {
+        long docCount = docCountProvider.getDocCount(doc);
+        if (docCounts.increment(bucketOrd, docCount) == docCount) {
             // We calculate the final number of buckets only during the reduce phase. But we still need to
             // trigger bucket consumer from time to time in order to give it a chance to check available memory and break
             // the execution if we are running out. To achieve that we are passing 0 as a bucket count.
@@ -142,11 +151,11 @@ public final void mergeBuckets(long[] mergeMap, long newNumBuckets) {
      * merge the actual ordinals and doc ID deltas.
      */
     public final void mergeBuckets(long newNumBuckets, LongUnaryOperator mergeMap) {
-        try (IntArray oldDocCounts = docCounts) {
-            docCounts = bigArrays.newIntArray(newNumBuckets, true);
+        try (LongArray oldDocCounts = docCounts) {
+            docCounts = bigArrays.newLongArray(newNumBuckets, true);
             docCounts.fill(0, newNumBuckets, 0);
             for (long i = 0; i < oldDocCounts.size(); i++) {
-                int docCount = oldDocCounts.get(i);
+                long docCount = oldDocCounts.get(i);
 
                 if (docCount == 0) continue;
 
@@ -159,14 +168,14 @@ public final void mergeBuckets(long newNumBuckets, LongUnaryOperator mergeMap) {
         }
     }
 
-    public IntArray getDocCounts() {
+    public LongArray getDocCounts() {
         return docCounts;
     }
 
     /**
      * Utility method to increment the doc counts of the given bucket (identified by the bucket ordinal)
      */
-    public final void incrementBucketDocCount(long bucketOrd, int inc) {
+    public final void incrementBucketDocCount(long bucketOrd, long inc) {
         docCounts = bigArrays.grow(docCounts, bucketOrd + 1);
         docCounts.increment(bucketOrd, inc);
     }
@@ -174,7 +183,7 @@ public final void incrementBucketDocCount(long bucketOrd, int inc) {
     /**
      * Utility method to return the number of documents that fell in the given bucket (identified by the bucket ordinal)
      */
-    public final int bucketDocCount(long bucketOrd) {
+    public final long bucketDocCount(long bucketOrd) {
         if (bucketOrd >= docCounts.size()) {
             // This may happen eg. if no document in the highest buckets is accepted by a sub aggregator.
             // For example, if there is a long terms agg on 3 terms 1,2,3 with a sub filter aggregator and if no document with 3 as a value
@@ -325,9 +334,14 @@ protected final <B> InternalAggregation[] buildAggregationsForFixedBucketCount(
         return results;
     }
 
+    /**
+     * A bucket builder for a fixed count
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     protected interface BucketBuilderForFixedCount<B> {
-        B build(int offsetInOwningOrd, int docCount, InternalAggregations subAggregationResults);
+        B build(int offsetInOwningOrd, long docCount, InternalAggregations subAggregationResults);
     }
 
     /**
@@ -350,6 +364,11 @@ protected final InternalAggregation[] buildAggregationsForSingleBucket(long[] ow
         return results;
     }
 
+    /**
+     * A single bucket result builder
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     protected interface SingleBucketResultBuilder {
         InternalAggregation build(long owningBucketOrd, InternalAggregations subAggregationResults);
@@ -410,11 +429,21 @@ protected final <B> InternalAggregation[] buildAggregationsForVariableBuckets(
         return results;
     }
 
+    /**
+     * A bucket builder for a variable
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     protected interface BucketBuilderForVariable<B> {
-        B build(long bucketValue, int docCount, InternalAggregations subAggregationResults);
+        B build(long bucketValue, long docCount, InternalAggregations subAggregationResults);
     }
 
+    /**
+     * A result builder for a bucket variable
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     protected interface ResultBuilderForVariable<B> {
         InternalAggregation build(long owninigBucketOrd, List<B> buckets);
@@ -441,7 +470,7 @@ public BucketComparator bucketComparator(String key, SortOrder order) {
             return super.bucketComparator(key, order);
         }
         if (key == null || "doc_count".equals(key)) {
-            return (lhs, rhs) -> order.reverseMul() * Integer.compare(bucketDocCount(lhs), bucketDocCount(rhs));
+            return (lhs, rhs) -> order.reverseMul() * Long.compare(bucketDocCount(lhs), bucketDocCount(rhs));
         }
         throw new IllegalArgumentException(
             "Ordering on a single-bucket aggregation can only be done on its doc_count. "
@@ -453,6 +482,13 @@ public BucketComparator bucketComparator(String key, SortOrder order) {
         );
     }
 
+    @Override
+    protected void preGetSubLeafCollectors(LeafReaderContext ctx) throws IOException {
+        super.preGetSubLeafCollectors(ctx);
+        // Set LeafReaderContext to the doc_count provider
+        docCountProvider.setLeafReaderContext(ctx);
+    }
+
     public static boolean descendsFromGlobalAggregator(Aggregator parent) {
         while (parent != null) {
             if (parent.getClass() == GlobalAggregator.class) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferableBucketAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferableBucketAggregator.java
index 8efbad76b82cd..5f2dc58236341 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferableBucketAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferableBucketAggregator.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
-import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.BucketCollector;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.MultiBucketCollector;
 import org.opensearch.search.internal.SearchContext;
 
@@ -45,6 +45,11 @@
 import java.util.Map;
 import java.util.function.BiConsumer;
 
+/**
+ * Aggregator that defers collecting docs based on some metric
+ *
+ * @opensearch.internal
+ */
 public abstract class DeferableBucketAggregator extends BucketsAggregator {
     /**
      * Wrapper that records collections. Non-null if any aggregations have
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferringBucketCollector.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferringBucketCollector.java
index 8bb5074acbaad..cfac1046c77b4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferringBucketCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/DeferringBucketCollector.java
@@ -48,6 +48,8 @@
 /**
  * A {@link BucketCollector} that records collected doc IDs and buckets and
  * allows to replay a subset of the collected buckets.
+ *
+ * @opensearch.internal
  */
 public abstract class DeferringBucketCollector extends BucketCollector {
 
@@ -70,6 +72,11 @@ public Aggregator wrap(final Aggregator in) {
         return new WrappedAggregator(in);
     }
 
+    /**
+     * A wrapped aggregator
+     *
+     * @opensearch.internal
+     */
     protected class WrappedAggregator extends Aggregator {
         private Aggregator in;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/DocCountProvider.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/DocCountProvider.java
new file mode 100644
index 0000000000000..30fe16ec4eb0e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/DocCountProvider.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.aggregations.bucket;
+
+import org.apache.lucene.index.DocValues;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NumericDocValues;
+import org.opensearch.index.mapper.DocCountFieldMapper;
+
+import java.io.IOException;
+
+/**
+ * An implementation of a doc_count provider that reads the value
+ * of the _doc_count field in the document. If a document does not have a
+ * _doc_count field the implementation will return 1 as the default value.
+ */
+public class DocCountProvider {
+
+    private NumericDocValues docCountValues;
+
+    public long getDocCount(int doc) throws IOException {
+        if (docCountValues != null && docCountValues.advanceExact(doc)) {
+            return docCountValues.longValue();
+        } else {
+            return 1L;
+        }
+    }
+
+    public void setLeafReaderContext(LeafReaderContext ctx) throws IOException {
+        docCountValues = DocValues.getNumeric(ctx.reader(), DocCountFieldMapper.NAME);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtils.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/GeoTileUtils.java
similarity index 81%
rename from server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtils.java
rename to server/src/main/java/org/opensearch/search/aggregations/bucket/GeoTileUtils.java
index d520cc995bbfb..de74055bb94f3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtils.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/GeoTileUtils.java
@@ -29,19 +29,22 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.bucket.geogrid;
+package org.opensearch.search.aggregations.bucket;
 
 import org.apache.lucene.geo.GeoEncodingUtils;
 import org.apache.lucene.util.SloppyMath;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.geo.GeoShapeDocValue;
 import org.opensearch.common.util.OpenSearchSloppyMath;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Rectangle;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 
 import static org.opensearch.common.geo.GeoUtils.normalizeLat;
@@ -54,6 +57,8 @@
  *   bits 58..63 -- zoom (0..29)
  *   bits 29..57 -- X tile index (0..2^zoom)
  *   bits  0..28 -- Y tile index (0..2^zoom)
+ *
+ * @opensearch.internal
  */
 public final class GeoTileUtils {
 
@@ -102,7 +107,7 @@ private GeoTileUtils() {}
      * @param parser {@link XContentParser} to parse the value from
      * @return int representing precision
      */
-    static int parsePrecision(XContentParser parser) throws IOException, OpenSearchParseException {
+    public static int parsePrecision(XContentParser parser) throws IOException, OpenSearchParseException {
         final Object node = parser.currentToken().equals(XContentParser.Token.VALUE_NUMBER)
             ? Integer.valueOf(parser.intValue())
             : parser.text();
@@ -247,10 +252,17 @@ public static String stringEncode(long hash) {
         return "" + res[0] + "/" + res[1] + "/" + res[2];
     }
 
+    /**
+     * Encode lon/lat to the geotile based string format which is "zoom/x/y"
+     */
+    public static String stringEncode(double longitude, double latitude, int precision) {
+        return stringEncode(longEncode(longitude, latitude, precision));
+    }
+
     /**
      * Decode long hash as a GeoPoint (center of the tile)
      */
-    static GeoPoint hashToGeoPoint(long hash) {
+    public static GeoPoint hashToGeoPoint(long hash) {
         int[] res = parseHash(hash);
         return zxyToGeoPoint(res[0], res[1], res[2]);
     }
@@ -258,7 +270,7 @@ static GeoPoint hashToGeoPoint(long hash) {
     /**
      * Decode a string bucket key in "zoom/x/y" format to a GeoPoint (center of the tile)
      */
-    static GeoPoint keyToGeoPoint(String hashAsString) {
+    public static GeoPoint keyToGeoPoint(String hashAsString) {
         int[] hashAsInts = parseHash(hashAsString);
         return zxyToGeoPoint(hashAsInts[0], hashAsInts[1], hashAsInts[2]);
     }
@@ -276,6 +288,40 @@ public static Rectangle toBoundingBox(String hash) {
         return toBoundingBox(hashAsInts[1], hashAsInts[2], hashAsInts[0]);
     }
 
+    /**
+     * The function encodes the shape provided as {@link GeoShapeDocValue} to a {@link List} of {@link Long} values
+     * (representing the GeoTiles) which are intersecting with the shapes at a given precision.
+     *
+     * @param geoShapeDocValue {@link GeoShapeDocValue}
+     * @param precision int
+     * @return {@link List} of {@link Long}
+     */
+    public static List<Long> encodeShape(final GeoShapeDocValue geoShapeDocValue, final int precision) {
+        final GeoShapeDocValue.BoundingRectangle boundingRectangle = geoShapeDocValue.getBoundingRectangle();
+        // generate all the grid long values that this shape intersects.
+        final long totalTilesAtPrecision = 1L << checkPrecisionRange(precision);
+        int maxXTile = getXTile(boundingRectangle.getMaxX(), totalTilesAtPrecision);
+        int minXTile = getXTile(boundingRectangle.getMinX(), totalTilesAtPrecision);
+        // as tuples in tiles are x,y and y(lat) increases from north to south in tiles, so for minYTile we need to
+        // take maxY and for maxYTile we need to take minY.
+        int minYTile = getYTile(boundingRectangle.getMaxY(), totalTilesAtPrecision);
+        int maxYTile = getYTile(boundingRectangle.getMinY(), totalTilesAtPrecision);
+        final List<Long> encodedValues = new ArrayList<>();
+        for (int x = minXTile; x <= maxXTile; x++) {
+            for (int y = minYTile; y <= maxYTile; y++) {
+                // Convert the precision, x , y to encoded value.
+                long encodedValue = longEncodeTiles(precision, x, y);
+                // Convert encoded value to rectangle
+                final Rectangle tileRectangle = toBoundingBox(encodedValue);
+                // check to see if the GeoShape is intersecting with the rectangle.
+                if (geoShapeDocValue.isIntersectingRectangle(tileRectangle)) {
+                    encodedValues.add(encodedValue);
+                }
+            }
+        }
+        return encodedValues;
+    }
+
     public static Rectangle toBoundingBox(int xTile, int yTile, int precision) {
         final double tiles = validateZXY(precision, xTile, yTile);
         final double minN = Math.PI - (2.0 * Math.PI * (yTile + 1)) / tiles;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/InternalSingleBucketAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/InternalSingleBucketAggregation.java
index bba1e526f6985..03fade2edb392 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/InternalSingleBucketAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/InternalSingleBucketAggregation.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -51,6 +51,8 @@
 
 /**
  * A base class for all the single bucket aggregations.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalSingleBucketAggregation extends InternalAggregation implements SingleBucketAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/IteratorAndCurrent.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/IteratorAndCurrent.java
index e0e14640d83f7..470fc0bc05389 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/IteratorAndCurrent.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/IteratorAndCurrent.java
@@ -36,6 +36,11 @@
 
 import java.util.Iterator;
 
+/**
+ * Utility class for keeping track of a current item in an iterator
+ *
+ * @opensearch.internal
+ */
 public class IteratorAndCurrent<B extends InternalMultiBucketAggregation.InternalBucket> implements Iterator<B> {
     private final Iterator<B> iterator;
     private B current;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/LocalBucketCountThresholds.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/LocalBucketCountThresholds.java
new file mode 100644
index 0000000000000..98dc07cec49ab
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/LocalBucketCountThresholds.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket;
+
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
+
+/**
+ * BucketCountThresholds type that holds the local (either shard level or request level) bucket count thresholds in minDocCount and requireSize fields.
+ * Similar to {@link TermsAggregator.BucketCountThresholds} however only provides getters for the local members and no setters.
+ *
+ * @opensearch.internal
+ */
+public class LocalBucketCountThresholds {
+
+    private final long minDocCount;
+    private final int requiredSize;
+
+    public LocalBucketCountThresholds(long localminDocCount, int localRequiredSize) {
+        this.minDocCount = localminDocCount;
+        this.requiredSize = localRequiredSize;
+    }
+
+    public int getRequiredSize() {
+        return requiredSize;
+    }
+
+    public long getMinDocCount() {
+        return minDocCount;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollector.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollector.java
index 4edb13dbba676..8d35c1edc8cb0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollector.java
@@ -45,6 +45,8 @@
  * matches and then is able to replay a given subset of buckets. Exposes
  * mergeBuckets, which can be invoked by the aggregator when increasing the
  * rounding interval.
+ *
+ * @opensearch.internal
  */
 public class MergingBucketsDeferringCollector extends BestBucketsDeferringCollector {
     public MergingBucketsDeferringCollector(SearchContext context, boolean isGlobal) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/MultiBucketsAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/MultiBucketsAggregation.java
index 437fc8a372d1c..0182282c986a7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/MultiBucketsAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/MultiBucketsAggregation.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.HasAggregations;
@@ -41,6 +41,8 @@
 
 /**
  * An aggregation that returns multiple buckets
+ *
+ * @opensearch.internal
  */
 public interface MultiBucketsAggregation extends Aggregation {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/ParsedSingleBucketAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/ParsedSingleBucketAggregation.java
index ddbbb3ed4f830..6f946dc50b9b4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/ParsedSingleBucketAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/ParsedSingleBucketAggregation.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedAggregation;
@@ -43,10 +43,12 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A base class for all the single bucket aggregations.
+ *
+ * @opensearch.internal
  */
 public abstract class ParsedSingleBucketAggregation extends ParsedAggregation implements SingleBucketAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregation.java
index b6e5acc39fee1..af0babcc1c22f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregation.java
@@ -38,6 +38,8 @@
 
 /**
  * A single bucket aggregation
+ *
+ * @opensearch.internal
  */
 public interface SingleBucketAggregation extends Aggregation, HasAggregations {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregator.java
index b6b51f707ceba..268e5f2aaf90d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/SingleBucketAggregator.java
@@ -33,5 +33,7 @@
 
 /**
  * A bucket aggregator that doesn't create new buckets.
+ *
+ * @opensearch.internal
  */
 public interface SingleBucketAggregator {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrix.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrix.java
index 4bf071aa23bf9..5cb8af37323e5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrix.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrix.java
@@ -40,6 +40,8 @@
  * A multi bucket aggregation where the buckets are defined by a set of filters
  * (a bucket is produced per filter plus a bucket for each non-empty filter
  * intersection so A, B and A&amp;B).
+ *
+ * @opensearch.internal
  */
 public interface AdjacencyMatrix extends MultiBucketsAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregationBuilder.java
index 640cceacb197d..743d0023364fa 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.bucket.adjacency;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
@@ -59,6 +59,11 @@
 import java.util.Map.Entry;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for adjacency_matrix agg
+ *
+ * @opensearch.internal
+ */
 public class AdjacencyMatrixAggregationBuilder extends AbstractAggregationBuilder<AdjacencyMatrixAggregationBuilder> {
     public static final String NAME = "adjacency_matrix";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregator.java
index b1054a01448f5..ef1795f425240 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregator.java
@@ -35,15 +35,15 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.Bits;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -66,11 +66,17 @@
 /**
  * Aggregation for adjacency matrices.
  *
+ * @opensearch.internal
  */
 public class AdjacencyMatrixAggregator extends BucketsAggregator {
 
     public static final ParseField FILTERS_FIELD = new ParseField("filters");
 
+    /**
+     * A keyed filter
+     *
+     * @opensearch.internal
+     */
     protected static class KeyedFilter implements Writeable, ToXContentFragment {
         private final String key;
         private final QueryBuilder filter;
@@ -222,7 +228,7 @@ public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws I
             List<InternalAdjacencyMatrix.InternalBucket> buckets = new ArrayList<>(filters.length);
             for (int i = 0; i < keys.length; i++) {
                 long bucketOrd = bucketOrd(owningBucketOrds[owningBucketOrdIdx], i);
-                int docCount = bucketDocCount(bucketOrd);
+                long docCount = bucketDocCount(bucketOrd);
                 // Empty buckets are not returned because this aggregation will commonly be used under a
                 // a date-histogram where we will look for transactions over time and can expect many
                 // empty buckets.
@@ -239,7 +245,7 @@ public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws I
             for (int i = 0; i < keys.length; i++) {
                 for (int j = i + 1; j < keys.length; j++) {
                     long bucketOrd = bucketOrd(owningBucketOrds[owningBucketOrdIdx], pos);
-                    int docCount = bucketDocCount(bucketOrd);
+                    long docCount = bucketDocCount(bucketOrd);
                     // Empty buckets are not returned due to potential for very sparse matrices
                     if (docCount > 0) {
                         String intersectKey = keys[i] + separator + keys[j];
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregatorFactory.java
index 7fffcff7b5db2..99ffb563ba2a8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/AdjacencyMatrixAggregatorFactory.java
@@ -48,6 +48,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for adjacency_matrix agg
+ *
+ * @opensearch.internal
+ */
 public class AdjacencyMatrixAggregatorFactory extends AggregatorFactory {
 
     private final String[] keys;
@@ -86,4 +91,8 @@ public Aggregator createInternal(
         return new AdjacencyMatrixAggregator(name, factories, separator, keys, weights, searchContext, parent, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/InternalAdjacencyMatrix.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/InternalAdjacencyMatrix.java
index 99a62621946e4..d96b1f00e488e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/InternalAdjacencyMatrix.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/InternalAdjacencyMatrix.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.adjacency;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
@@ -48,9 +48,20 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Internal class used to represent an adjacency matrix as a collection of buckets
+ *
+ * @opensearch.internal
+ */
 public class InternalAdjacencyMatrix extends InternalMultiBucketAggregation<InternalAdjacencyMatrix, InternalAdjacencyMatrix.InternalBucket>
     implements
         AdjacencyMatrix {
+
+    /**
+     * An internal bucket of the adjacency matrix
+     *
+     * @opensearch.internal
+     */
     public static class InternalBucket extends InternalMultiBucketAggregation.InternalBucket implements AdjacencyMatrix.Bucket {
 
         private final String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/ParsedAdjacencyMatrix.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/ParsedAdjacencyMatrix.java
index 27e0bf40ca017..e06dc6b01848e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/ParsedAdjacencyMatrix.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/ParsedAdjacencyMatrix.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.adjacency;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
@@ -41,6 +41,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Internal class used to hold a parsed adjacency matrix as a collection of buckets
+ *
+ * @opensearch.internal
+ */
 public class ParsedAdjacencyMatrix extends ParsedMultiBucketAggregation<ParsedAdjacencyMatrix.ParsedBucket> implements AdjacencyMatrix {
 
     private Map<String, ParsedBucket> bucketMap;
@@ -85,6 +90,11 @@ public static ParsedAdjacencyMatrix fromXContent(XContentParser parser, String n
         return aggregation;
     }
 
+    /**
+     * A parsed bucket
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements AdjacencyMatrix.Bucket {
 
         private String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/package-info.java
new file mode 100644
index 0000000000000..93eed08c5dd2d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/adjacency/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Adjacency Aggregation package. */
+package org.opensearch.search.aggregations.bucket.adjacency;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/BinaryValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/BinaryValuesSource.java
index 44a29e2251b13..54fd261f88c35 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/BinaryValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/BinaryValuesSource.java
@@ -55,6 +55,8 @@
 
 /**
  * A {@link SingleDimensionValuesSource} for binary source ({@link BytesRef}).
+ *
+ * @opensearch.internal
  */
 class BinaryValuesSource extends SingleDimensionValuesSource<BytesRef> {
     private final LongConsumer breakerConsumer;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregation.java
index e245aefcbbcc4..6295b2cec2e16 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregation.java
@@ -32,14 +32,24 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation creates a composite of multiple aggs
+ *
+ * @opensearch.internal
+ */
 public interface CompositeAggregation extends MultiBucketsAggregation {
+    /**
+     * Bucket in a composite agg
+     *
+     * @opensearch.internal
+     */
     interface Bucket extends MultiBucketsAggregation.Bucket {
         Map<String, Object> getKey();
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilder.java
index 0dfc1de3503e8..5e8791441d83a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilder.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -47,14 +49,22 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.function.Consumer;
+import java.util.function.Function;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Aggregation Builder for composite agg
+ *
+ * @opensearch.internal
+ */
 public class CompositeAggregationBuilder extends AbstractAggregationBuilder<CompositeAggregationBuilder> {
     public static final String NAME = "composite";
 
@@ -77,14 +87,55 @@ public class CompositeAggregationBuilder extends AbstractAggregationBuilder<Comp
         PARSER.declareObject(CompositeAggregationBuilder::aggregateAfter, (p, context) -> p.map(), AFTER_FIELD_NAME);
     }
 
-    public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
+    static final Map<Class<?>, Byte> BUILDER_CLASS_TO_BYTE_CODE = new HashMap<>();
+    static final Map<String, CompositeAggregationParsingFunction> BUILDER_TYPE_TO_PARSER = new HashMap<>();
+    static final Map<Integer, Writeable.Reader<? extends CompositeValuesSourceBuilder<?>>> BYTE_CODE_TO_COMPOSITE_VALUE_SOURCE_READER =
+        new HashMap<>();
+    static final Map<
+        String,
+        Writeable.Reader<? extends CompositeValuesSourceBuilder<?>>> AGGREGATION_TYPE_TO_COMPOSITE_VALUE_SOURCE_READER = new HashMap<>();
+    static final Map<Class<?>, String> BUILDER_CLASS_TO_AGGREGATION_TYPE = new HashMap<>();
+
+    public static void registerAggregators(ValuesSourceRegistry.Builder builder, final List<SearchPlugin> plugins) {
         DateHistogramValuesSourceBuilder.register(builder);
         HistogramValuesSourceBuilder.register(builder);
-        GeoTileGridValuesSourceBuilder.register(builder);
         TermsValuesSourceBuilder.register(builder);
+        // Register All other aggregations that wants to be part of Composite Aggregation which are provided in
+        // Plugins along with their parsers and serialisation codes
+        registerCompositeAggregatorsPlugins(plugins, SearchPlugin::getCompositeAggregations, (compositeAggregationSpec) -> {
+            compositeAggregationSpec.getAggregatorRegistrar().accept(builder);
+            BUILDER_TYPE_TO_PARSER.put(compositeAggregationSpec.getAggregationType(), compositeAggregationSpec.getParsingFunction());
+            // This is added for backward compatibility, so that we can move away from byte code in the serialisation
+            if (compositeAggregationSpec.getByteCode() != null) {
+                BYTE_CODE_TO_COMPOSITE_VALUE_SOURCE_READER.put(
+                    (int) compositeAggregationSpec.getByteCode(),
+                    compositeAggregationSpec.getReader()
+                );
+                BUILDER_CLASS_TO_BYTE_CODE.put(
+                    compositeAggregationSpec.getValueSourceBuilderClass(),
+                    compositeAggregationSpec.getByteCode()
+                );
+            }
+            AGGREGATION_TYPE_TO_COMPOSITE_VALUE_SOURCE_READER.put(
+                compositeAggregationSpec.getAggregationType(),
+                compositeAggregationSpec.getReader()
+            );
+            BUILDER_CLASS_TO_AGGREGATION_TYPE.put(
+                compositeAggregationSpec.getValueSourceBuilderClass(),
+                compositeAggregationSpec.getAggregationType()
+            );
+        });
         builder.registerUsage(NAME);
     }
 
+    private static void registerCompositeAggregatorsPlugins(
+        final List<SearchPlugin> plugins,
+        final Function<SearchPlugin, List<SearchPlugin.CompositeAggregationSpec>> producer,
+        final Consumer<SearchPlugin.CompositeAggregationSpec> consumer
+    ) {
+        plugins.forEach(searchPlugin -> producer.apply(searchPlugin).forEach(consumer));
+    }
+
     private List<CompositeValuesSourceBuilder<?>> sources;
     private Map<String, Object> after;
     private int size = 10;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationFactory.java
index d7383285ddd1c..2ff79fb623def 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationFactory.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for composite agg
+ *
+ * @opensearch.internal
+ */
 class CompositeAggregationFactory extends AggregatorFactory {
     private final int size;
     private final CompositeValuesSourceConfig[] sources;
@@ -72,4 +77,9 @@ protected Aggregator createInternal(
     ) throws IOException {
         return new CompositeAggregator(name, factories, searchContext, parent, metadata, size, sources, afterKey);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationParsingFunction.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationParsingFunction.java
new file mode 100644
index 0000000000000..622e1d9b8cf64
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationParsingFunction.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.composite;
+
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+
+/**
+ * A functional interface which encapsulates the parsing function to be called for the aggregation which is
+ * also registered as CompositeAggregation.
+ */
+@FunctionalInterface
+public interface CompositeAggregationParsingFunction {
+    CompositeValuesSourceBuilder<?> parse(final String name, final XContentParser parser) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregator.java
index 6af887201d994..f2a4d5cd46127 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregator.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.index.NumericDocValues;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
-import org.opensearch.lucene.queries.SearchAfterSortedDocQuery;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.CollectionTerminatedException;
@@ -59,6 +58,7 @@
 import org.apache.lucene.util.RoaringDocIdSet;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.index.IndexSortConfig;
+import org.opensearch.lucene.queries.SearchAfterSortedDocQuery;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -86,6 +86,11 @@
 
 import static org.opensearch.search.aggregations.MultiBucketConsumerService.MAX_BUCKET_SETTING;
 
+/**
+ * Main aggregator that aggregates docs from mulitple aggregations
+ *
+ * @opensearch.internal
+ */
 final class CompositeAggregator extends BucketsAggregator {
     private final int size;
     private final List<String> sourceNames;
@@ -191,7 +196,7 @@ public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws I
             int slot = queue.pop();
             CompositeKey key = queue.toCompositeKey(slot);
             InternalAggregations aggs = subAggsForBuckets[slot];
-            int docCount = queue.getDocCount(slot);
+            long docCount = queue.getDocCount(slot);
             buckets[queue.size()] = new InternalComposite.InternalBucket(
                 sourceNames,
                 formats,
@@ -499,7 +504,8 @@ private LeafBucketCollector getFirstPassCollector(RoaringDocIdSet.Builder builde
             @Override
             public void collect(int doc, long bucket) throws IOException {
                 try {
-                    if (queue.addIfCompetitive(indexSortPrefix)) {
+                    long docCount = docCountProvider.getDocCount(doc);
+                    if (queue.addIfCompetitive(indexSortPrefix, docCount)) {
                         if (builder != null && lastDoc != doc) {
                             builder.add(doc);
                             lastDoc = doc;
@@ -572,6 +578,11 @@ public void collect(int doc, long zeroBucket) throws IOException {
         };
     }
 
+    /**
+     * An entry in the composite aggregator
+     *
+     * @opensearch.internal
+     */
     private static class Entry {
         final LeafReaderContext context;
         final DocIdSet docIdSet;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeKey.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeKey.java
index cb2801e625bfb..5ddeb22d33a6f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeKey.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeKey.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Arrays;
 
 /**
  * A key that is composed of multiple {@link Comparable} values.
+ *
+ * @opensearch.internal
  */
 class CompositeKey implements Writeable {
     private final Comparable[] values;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueue.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueue.java
index a7963532235ec..6ee1682a7b196 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueue.java
@@ -38,7 +38,7 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.IntArray;
+import org.opensearch.common.util.LongArray;
 import org.opensearch.search.aggregations.LeafBucketCollector;
 
 import java.io.IOException;
@@ -47,6 +47,8 @@
 
 /**
  * A specialized {@link PriorityQueue} implementation for composite buckets.
+ *
+ * @opensearch.internal
  */
 final class CompositeValuesCollectorQueue extends PriorityQueue<Integer> implements Releasable {
     private class Slot {
@@ -78,7 +80,7 @@ public int hashCode() {
     private final Map<Slot, Integer> map;
     private final SingleDimensionValuesSource<?>[] arrays;
 
-    private IntArray docCounts;
+    private LongArray docCounts;
     private boolean afterKeyIsSet = false;
 
     /**
@@ -101,7 +103,7 @@ public int hashCode() {
                 sources[i].setAfter(afterKey.get(i));
             }
         }
-        this.docCounts = bigArrays.newIntArray(1, false);
+        this.docCounts = bigArrays.newLongArray(1, false);
     }
 
     @Override
@@ -141,19 +143,19 @@ Comparable getUpperValueLeadSource() throws IOException {
     /**
      * Returns the document count in <code>slot</code>.
      */
-    int getDocCount(int slot) {
+    long getDocCount(int slot) {
         return docCounts.get(slot);
     }
 
     /**
      * Copies the current value in <code>slot</code>.
      */
-    private void copyCurrent(int slot) {
+    private void copyCurrent(int slot, long value) {
         for (int i = 0; i < arrays.length; i++) {
             arrays[i].copyCurrent(slot);
         }
         docCounts = bigArrays.grow(docCounts, slot + 1);
-        docCounts.set(slot, 1);
+        docCounts.set(slot, value);
     }
 
     /**
@@ -263,8 +265,8 @@ LeafBucketCollector getLeafCollector(Comparable forceLeadSourceValue, LeafReader
      * Check if the current candidate should be added in the queue.
      * @return <code>true</code> if the candidate is competitive (added or already in the queue).
      */
-    boolean addIfCompetitive() {
-        return addIfCompetitive(0);
+    boolean addIfCompetitive(long inc) {
+        return addIfCompetitive(0, inc);
     }
 
     /**
@@ -277,12 +279,12 @@ boolean addIfCompetitive() {
      *
      * @throws CollectionTerminatedException if the current collection can be terminated early due to index sorting.
      */
-    boolean addIfCompetitive(int indexSortSourcePrefix) {
+    boolean addIfCompetitive(int indexSortSourcePrefix, long inc) {
         // checks if the candidate key is competitive
         Integer topSlot = compareCurrent();
         if (topSlot != null) {
             // this key is already in the top N, skip it
-            docCounts.increment(topSlot, 1);
+            docCounts.increment(topSlot, inc);
             return true;
         }
         if (afterKeyIsSet) {
@@ -323,7 +325,7 @@ boolean addIfCompetitive(int indexSortSourcePrefix) {
             newSlot = size();
         }
         // move the candidate key to its new slot
-        copyCurrent(newSlot);
+        copyCurrent(newSlot, inc);
         map.put(new Slot(newSlot), newSlot);
         add(newSlot);
         return true;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceBuilder.java
index 9ac43c812e41c..89a85866d6873 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations.bucket.composite;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
@@ -55,6 +55,8 @@
 
 /**
  * A {@link ValuesSource} builder for {@link CompositeAggregationBuilder}
+ *
+ * @opensearch.internal
  */
 public abstract class CompositeValuesSourceBuilder<AB extends CompositeValuesSourceBuilder<AB>> implements Writeable, ToXContentFragment {
 
@@ -67,11 +69,11 @@ public abstract class CompositeValuesSourceBuilder<AB extends CompositeValuesSou
     private SortOrder order = SortOrder.ASC;
     private String format = null;
 
-    CompositeValuesSourceBuilder(String name) {
+    public CompositeValuesSourceBuilder(String name) {
         this.name = name;
     }
 
-    CompositeValuesSourceBuilder(StreamInput in) throws IOException {
+    public CompositeValuesSourceBuilder(StreamInput in) throws IOException {
         this.name = in.readString();
         this.field = in.readOptionalString();
         if (in.readBoolean()) {
@@ -165,7 +167,7 @@ public String name() {
         return name;
     }
 
-    abstract String type();
+    protected abstract String type();
 
     /**
      * Sets the field to use for this source
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceConfig.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceConfig.java
index bcde67023b1ff..788a4ddc15374 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceConfig.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceConfig.java
@@ -43,8 +43,18 @@
 
 import java.util.function.LongConsumer;
 
+/**
+ * Field configuration class for composite values
+ *
+ * @opensearch.internal
+ */
 public class CompositeValuesSourceConfig {
 
+    /**
+     * A single dimension provider
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface SingleDimensionValuesSourceProvider {
         SingleDimensionValuesSource<?> createValuesSource(
@@ -78,7 +88,7 @@ SingleDimensionValuesSource<?> createValuesSource(
      * @param missingBucket If <code>true</code> an explicit <code>null</code> bucket will represent documents with missing values.
      * @param hasScript <code>true</code> if the source contains a script that can change the value.
      */
-    CompositeValuesSourceConfig(
+    public CompositeValuesSourceConfig(
         String name,
         @Nullable MappedFieldType fieldType,
         ValuesSource vs,
@@ -103,21 +113,21 @@ SingleDimensionValuesSource<?> createValuesSource(
     /**
      * Returns the name associated with this configuration.
      */
-    String name() {
+    protected String name() {
         return name;
     }
 
     /**
      * Returns the {@link MappedFieldType} for this config.
      */
-    MappedFieldType fieldType() {
+    public MappedFieldType fieldType() {
         return fieldType;
     }
 
     /**
      * Returns the {@link ValuesSource} for this configuration.
      */
-    ValuesSource valuesSource() {
+    public ValuesSource valuesSource() {
         return vs;
     }
 
@@ -125,35 +135,35 @@ ValuesSource valuesSource() {
      * The {@link DocValueFormat} to use for formatting the keys.
      * {@link DocValueFormat#RAW} means no formatting.
      */
-    DocValueFormat format() {
+    public DocValueFormat format() {
         return format;
     }
 
     /**
      * If true, an explicit `null bucket represents documents with missing values.
      */
-    boolean missingBucket() {
+    public boolean missingBucket() {
         return missingBucket;
     }
 
     /**
      * Return the {@link MissingOrder} for the config.
      */
-    MissingOrder missingOrder() {
+    public MissingOrder missingOrder() {
         return missingOrder;
     }
 
     /**
      * Returns true if the source contains a script that can change the value.
      */
-    boolean hasScript() {
+    protected boolean hasScript() {
         return hasScript;
     }
 
     /**
      * The sort order for the values source (e.g. -1 for descending and 1 for ascending).
      */
-    int reverseMul() {
+    public int reverseMul() {
         assert reverseMul == -1 || reverseMul == 1;
         return reverseMul;
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceParserHelper.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceParserHelper.java
index c1e64f57c10cc..4d496dd12fca7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceParserHelper.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesSourceParserHelper.java
@@ -33,26 +33,40 @@
 package org.opensearch.search.aggregations.bucket.composite;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.AbstractObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent.Params;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent.Params;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 import org.opensearch.search.aggregations.support.ValueType;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder.AGGREGATION_TYPE_TO_COMPOSITE_VALUE_SOURCE_READER;
+import static org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder.BUILDER_CLASS_TO_AGGREGATION_TYPE;
+import static org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder.BUILDER_CLASS_TO_BYTE_CODE;
+import static org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder.BUILDER_TYPE_TO_PARSER;
+import static org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder.BYTE_CODE_TO_COMPOSITE_VALUE_SOURCE_READER;
 
+/**
+ * Helper class for obtaining values source parsers for different aggs
+ *
+ * @opensearch.internal
+ */
 public class CompositeValuesSourceParserHelper {
 
-    static <VB extends CompositeValuesSourceBuilder<VB>, T> void declareValuesSourceFields(AbstractObjectParser<VB, T> objectParser) {
+    private static final int AGGREGATION_TYPE_REFERENCE = Byte.MAX_VALUE;
+
+    public static <VB extends CompositeValuesSourceBuilder<VB>, T> void declareValuesSourceFields(
+        AbstractObjectParser<VB, T> objectParser
+    ) {
         objectParser.declareField(VB::field, XContentParser::text, new ParseField("field"), ObjectParser.ValueType.STRING);
         objectParser.declareBoolean(VB::missingBucket, new ParseField("missing_bucket"));
         objectParser.declareString(VB::missingOrder, new ParseField(MissingOrder.NAME));
@@ -73,28 +87,45 @@ static <VB extends CompositeValuesSourceBuilder<VB>, T> void declareValuesSource
     }
 
     public static void writeTo(CompositeValuesSourceBuilder<?> builder, StreamOutput out) throws IOException {
-        final byte code;
+        int code = Byte.MIN_VALUE;
+        String aggregationType = null;
         if (builder.getClass() == TermsValuesSourceBuilder.class) {
             code = 0;
         } else if (builder.getClass() == DateHistogramValuesSourceBuilder.class) {
             code = 1;
         } else if (builder.getClass() == HistogramValuesSourceBuilder.class) {
             code = 2;
-        } else if (builder.getClass() == GeoTileGridValuesSourceBuilder.class) {
-            if (out.getVersion().before(LegacyESVersion.V_7_5_0)) {
-                throw new IOException(
-                    "Attempting to serialize ["
-                        + builder.getClass().getSimpleName()
-                        + "] to a node with unsupported version ["
-                        + out.getVersion()
-                        + "]"
-                );
-            }
-            code = 3;
         } else {
-            throw new IOException("invalid builder type: " + builder.getClass().getSimpleName());
+            if (!BUILDER_CLASS_TO_BYTE_CODE.containsKey(builder.getClass())
+                && !BUILDER_CLASS_TO_AGGREGATION_TYPE.containsKey(builder.getClass())) {
+                throw new IOException("invalid builder type: " + builder.getClass().getSimpleName());
+            }
+            aggregationType = BUILDER_CLASS_TO_AGGREGATION_TYPE.get(builder.getClass());
+            if (BUILDER_CLASS_TO_BYTE_CODE.containsKey(builder.getClass())) {
+                code = BUILDER_CLASS_TO_BYTE_CODE.get(builder.getClass());
+                if (code == 3 && out.getVersion().before(LegacyESVersion.V_7_5_0)) {
+                    throw new IOException(
+                        "Attempting to serialize ["
+                            + builder.getClass().getSimpleName()
+                            + "] to a node with unsupported version ["
+                            + out.getVersion()
+                            + "]"
+                    );
+                }
+            }
+        }
+
+        if (code != Byte.MIN_VALUE) {
+            out.writeByte((byte) code);
+        } else if (!BUILDER_CLASS_TO_BYTE_CODE.containsKey(builder.getClass())) {
+            /*
+             * This is added for backward compatibility when 1 data node is using the new code which is using the
+             * aggregation type and another is using the only byte code in the serialisation.
+             */
+            out.writeByte((byte) AGGREGATION_TYPE_REFERENCE);
+            assert aggregationType != null;
+            out.writeString(aggregationType);
         }
-        out.writeByte(code);
         builder.writeTo(out);
     }
 
@@ -107,10 +138,17 @@ public static CompositeValuesSourceBuilder<?> readFrom(StreamInput in) throws IO
                 return new DateHistogramValuesSourceBuilder(in);
             case 2:
                 return new HistogramValuesSourceBuilder(in);
-            case 3:
-                return new GeoTileGridValuesSourceBuilder(in);
+            case AGGREGATION_TYPE_REFERENCE:
+                final String aggregationType = in.readString();
+                if (!AGGREGATION_TYPE_TO_COMPOSITE_VALUE_SOURCE_READER.containsKey(aggregationType)) {
+                    throw new IOException("Invalid aggregation type " + aggregationType);
+                }
+                return (CompositeValuesSourceBuilder<?>) AGGREGATION_TYPE_TO_COMPOSITE_VALUE_SOURCE_READER.get(aggregationType).read(in);
             default:
-                throw new IOException("Invalid code " + code);
+                if (!BYTE_CODE_TO_COMPOSITE_VALUE_SOURCE_READER.containsKey(code)) {
+                    throw new IOException("Invalid code " + code);
+                }
+                return (CompositeValuesSourceBuilder<?>) BYTE_CODE_TO_COMPOSITE_VALUE_SOURCE_READER.get(code).read(in);
         }
     }
 
@@ -138,11 +176,11 @@ public static CompositeValuesSourceBuilder<?> fromXContent(XContentParser parser
             case HistogramValuesSourceBuilder.TYPE:
                 builder = HistogramValuesSourceBuilder.parse(name, parser);
                 break;
-            case GeoTileGridValuesSourceBuilder.TYPE:
-                builder = GeoTileGridValuesSourceBuilder.parse(name, parser);
-                break;
             default:
-                throw new ParsingException(parser.getTokenLocation(), "invalid source type: " + type);
+                if (!BUILDER_TYPE_TO_PARSER.containsKey(type)) {
+                    throw new ParsingException(parser.getTokenLocation(), "invalid source type: " + type);
+                }
+                builder = BUILDER_TYPE_TO_PARSER.get(type).parse(name, parser);
         }
         parser.nextToken();
         parser.nextToken();
@@ -158,4 +196,5 @@ public static XContentBuilder toXContent(CompositeValuesSourceBuilder<?> source,
         builder.endObject();
         return builder;
     }
+
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DateHistogramValuesSourceBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DateHistogramValuesSourceBuilder.java
index acab1790bfa21..567f7758eb9a4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DateHistogramValuesSourceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DateHistogramValuesSourceBuilder.java
@@ -34,15 +34,15 @@
 
 import org.apache.lucene.index.IndexReader;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
@@ -63,16 +63,24 @@
 import java.io.IOException;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
+import java.util.List;
 import java.util.Objects;
 import java.util.function.LongConsumer;
 
 /**
  * A {@link CompositeValuesSourceBuilder} that builds a {@link RoundingValuesSource} from a {@link Script} or
  * a field name using the provided interval.
+ *
+ * @opensearch.internal
  */
 public class DateHistogramValuesSourceBuilder extends CompositeValuesSourceBuilder<DateHistogramValuesSourceBuilder>
     implements
         DateIntervalConsumer {
+    /**
+     * Supplier for a composite date histogram
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface DateHistogramCompositeSupplier {
         CompositeValuesSourceConfig apply(
@@ -289,7 +297,7 @@ public DateHistogramValuesSourceBuilder offset(long offset) {
     public static void register(ValuesSourceRegistry.Builder builder) {
         builder.register(
             REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC),
+            List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC),
             (valuesSourceConfig, rounding, name, hasScript, format, missingBucket, missingOrder, order) -> {
                 ValuesSource.Numeric numeric = (ValuesSource.Numeric) valuesSourceConfig.getValuesSource();
                 // TODO once composite is plugged in to the values source registry or at least understands Date values source types use it
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DoubleValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DoubleValuesSource.java
index fb94ff194b950..970f07b6a9d74 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DoubleValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/DoubleValuesSource.java
@@ -50,6 +50,8 @@
 
 /**
  * A {@link SingleDimensionValuesSource} for doubles.
+ *
+ * @opensearch.internal
  */
 class DoubleValuesSource extends SingleDimensionValuesSource<Double> {
     private final CheckedFunction<LeafReaderContext, SortedNumericDoubleValues, IOException> docValuesFunc;
@@ -150,11 +152,9 @@ void setAfter(Comparable value) {
         } else if (value instanceof Number) {
             afterValue = ((Number) value).doubleValue();
         } else {
-            afterValue = format.parseDouble(
-                value.toString(),
-                false,
-                () -> { throw new IllegalArgumentException("now() is not supported in [after] key"); }
-            );
+            afterValue = format.parseDouble(value.toString(), false, () -> {
+                throw new IllegalArgumentException("now() is not supported in [after] key");
+            });
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GlobalOrdinalValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GlobalOrdinalValuesSource.java
index b4db4d8dd2a36..3e5c53d470f79 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GlobalOrdinalValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/GlobalOrdinalValuesSource.java
@@ -54,6 +54,8 @@
 
 /**
  * A {@link SingleDimensionValuesSource} for global ordinals.
+ *
+ * @opensearch.internal
  */
 class GlobalOrdinalValuesSource extends SingleDimensionValuesSource<BytesRef> {
     private final CheckedFunction<LeafReaderContext, SortedSetDocValues, IOException> docValuesFunc;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSource.java
index 59625bc3300e5..dbbc81a5a11ab 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSource.java
@@ -40,6 +40,11 @@
 
 import java.io.IOException;
 
+/**
+ * The values source for histogram agg
+ *
+ * @opensearch.internal
+ */
 class HistogramValuesSource extends ValuesSource.Numeric {
     private final Numeric vs;
     private final double interval;
@@ -58,6 +63,11 @@ public boolean isFloatingPoint() {
         return true;
     }
 
+    @Override
+    public boolean isBigInteger() {
+        return false;
+    }
+
     @Override
     public SortedNumericDoubleValues doubleValues(LeafReaderContext context) throws IOException {
         SortedNumericDoubleValues values = vs.doubleValues(context);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSourceBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSourceBuilder.java
index 1f1ed3b6254ba..208b8e12fe948 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSourceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/HistogramValuesSourceBuilder.java
@@ -33,12 +33,12 @@
 package org.opensearch.search.aggregations.bucket.composite;
 
 import org.apache.lucene.index.IndexReader;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.bucket.histogram.Histogram;
@@ -51,14 +51,22 @@
 import org.opensearch.search.sort.SortOrder;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Objects;
 import java.util.function.LongConsumer;
 
 /**
  * A {@link CompositeValuesSourceBuilder} that builds a {@link HistogramValuesSource} from another numeric values source
  * using the provided interval.
+ *
+ * @opensearch.internal
  */
 public class HistogramValuesSourceBuilder extends CompositeValuesSourceBuilder<HistogramValuesSourceBuilder> {
+    /**
+     * Composite histogram supplier
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface HistogramCompositeSupplier {
         CompositeValuesSourceConfig apply(
@@ -93,7 +101,7 @@ static HistogramValuesSourceBuilder parse(String name, XContentParser parser) th
     public static void register(ValuesSourceRegistry.Builder builder) {
         builder.register(
             REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC),
+            List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC),
             (valuesSourceConfig, interval, name, hasScript, format, missingBucket, missingOrder, order) -> {
                 ValuesSource.Numeric numeric = (ValuesSource.Numeric) valuesSourceConfig.getValuesSource();
                 final HistogramValuesSource vs = new HistogramValuesSource(numeric, interval);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/InternalComposite.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/InternalComposite.java
index c102095d93184..6591c9c054224 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/InternalComposite.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/InternalComposite.java
@@ -35,9 +35,9 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -58,6 +58,11 @@
 import java.util.PriorityQueue;
 import java.util.Set;
 
+/**
+ * Internal coordination class for composite aggs
+ *
+ * @opensearch.internal
+ */
 public class InternalComposite extends InternalMultiBucketAggregation<InternalComposite, InternalComposite.InternalBucket>
     implements
         CompositeAggregation {
@@ -312,6 +317,11 @@ public int hashCode() {
         return Objects.hash(super.hashCode(), size, buckets, afterKey, Arrays.hashCode(reverseMuls), Arrays.hashCode(missingOrders));
     }
 
+    /**
+     * The bucket iterator
+     *
+     * @opensearch.internal
+     */
     private static class BucketIterator implements Comparable<BucketIterator> {
         final Iterator<InternalBucket> it;
         InternalBucket current;
@@ -330,6 +340,11 @@ InternalBucket next() {
         }
     }
 
+    /**
+     * Internal bucket for the internal composite agg
+     *
+     * @opensearch.internal
+     */
     public static class InternalBucket extends InternalMultiBucketAggregation.InternalBucket
         implements
             CompositeAggregation.Bucket,
@@ -511,6 +526,11 @@ static Object formatObject(Object obj, DocValueFormat format) {
         return obj;
     }
 
+    /**
+     * An array map used for the internal composite agg
+     *
+     * @opensearch.internal
+     */
     static class ArrayMap extends AbstractMap<String, Object> implements Comparable<ArrayMap> {
         final List<String> keys;
         final Comparable[] values;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/LongValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/LongValuesSource.java
index 0ce147a138a96..48e080c1576dd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/LongValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/LongValuesSource.java
@@ -63,8 +63,10 @@
 
 /**
  * A {@link SingleDimensionValuesSource} for longs.
+ *
+ * @opensearch.internal
  */
-class LongValuesSource extends SingleDimensionValuesSource<Long> {
+public class LongValuesSource extends SingleDimensionValuesSource<Long> {
     private final BigArrays bigArrays;
     private final CheckedFunction<LeafReaderContext, SortedNumericDocValues, IOException> docValuesFunc;
     private final LongUnaryOperator rounding;
@@ -74,7 +76,7 @@ class LongValuesSource extends SingleDimensionValuesSource<Long> {
     private long currentValue;
     private boolean missingCurrentValue;
 
-    LongValuesSource(
+    public LongValuesSource(
         BigArrays bigArrays,
         MappedFieldType fieldType,
         CheckedFunction<LeafReaderContext, SortedNumericDocValues, IOException> docValuesFunc,
@@ -163,16 +165,14 @@ private int compareValues(long v1, long v2) {
     }
 
     @Override
-    void setAfter(Comparable value) {
+    protected void setAfter(Comparable value) {
         if (missingBucket && value == null) {
             afterValue = null;
         } else {
             // parse the value from a string in case it is a date or a formatted unsigned long.
-            afterValue = format.parseLong(
-                value.toString(),
-                false,
-                () -> { throw new IllegalArgumentException("now() is not supported in [after] key"); }
-            );
+            afterValue = format.parseLong(value.toString(), false, () -> {
+                throw new IllegalArgumentException("now() is not supported in [after] key");
+            });
         }
     }
 
@@ -219,7 +219,7 @@ public void collect(int doc, long bucket) throws IOException {
         };
     }
 
-    private static Query extractQuery(Query query) {
+    static Query extractQuery(Query query) {
         if (query instanceof BoostQuery) {
             return extractQuery(((BoostQuery) query).getQuery());
         } else if (query instanceof IndexOrDocValuesQuery) {
@@ -234,7 +234,7 @@ private static Query extractQuery(Query query) {
     /**
      * Returns true if we can use <code>query</code> with a {@link SortedDocsProducer} on <code>fieldName</code>.
      */
-    private static boolean checkMatchAllOrRangeQuery(Query query, String fieldName) {
+    static boolean checkMatchAllOrRangeQuery(Query query, String fieldName) {
         if (query == null) {
             return true;
         } else if (query.getClass() == MatchAllDocsQuery.class) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/ParsedComposite.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/ParsedComposite.java
index 5cbda5dca130a..8382b191025fe 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/ParsedComposite.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/ParsedComposite.java
@@ -32,16 +32,21 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * A composite result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedComposite extends ParsedMultiBucketAggregation<ParsedComposite.ParsedBucket> implements CompositeAggregation {
     private static final ObjectParser<ParsedComposite, Void> PARSER = new ObjectParser<>(
         ParsedComposite.class.getSimpleName(),
@@ -101,6 +106,11 @@ protected XContentBuilder doXContentBody(XContentBuilder builder, Params params)
         return CompositeAggregation.toXContentFragment(this, builder, params);
     }
 
+    /**
+     * Parsed bucket for the parsed composite agg
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements CompositeAggregation.Bucket {
         private Map<String, Object> key;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/PointsSortedDocsProducer.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/PointsSortedDocsProducer.java
index 8dbb902b96186..3d6730203b6ae 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/PointsSortedDocsProducer.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/PointsSortedDocsProducer.java
@@ -45,6 +45,8 @@
 
 /**
  * A {@link SortedDocsProducer} that can sort documents based on numerics indexed in the provided field.
+ *
+ * @opensearch.internal
  */
 class PointsSortedDocsProducer extends SortedDocsProducer {
     private final ToLongFunction<byte[]> bucketFunction;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/RoundingValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/RoundingValuesSource.java
index fc0dfe9a5a098..89315724ff9ed 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/RoundingValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/RoundingValuesSource.java
@@ -44,6 +44,8 @@
 /**
  * A wrapper for {@link ValuesSource.Numeric} that uses {@link Rounding} to transform the long values
  * produced by the underlying source.
+ *
+ * @opensearch.internal
  */
 class RoundingValuesSource extends ValuesSource.Numeric {
     private final ValuesSource.Numeric vs;
@@ -64,6 +66,11 @@ public boolean isFloatingPoint() {
         return false;
     }
 
+    @Override
+    public boolean isBigInteger() {
+        return false;
+    }
+
     public long round(long value) {
         return rounding.round(value);
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSource.java
index 94b108e863e3d..fe0801d6d230e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSource.java
@@ -50,8 +50,10 @@
 
 /**
  * A source that can record and compare values of similar type.
+ *
+ * @opensearch.internal
  */
-abstract class SingleDimensionValuesSource<T extends Comparable<T>> implements Releasable {
+public abstract class SingleDimensionValuesSource<T extends Comparable<T>> implements Releasable {
     protected final BigArrays bigArrays;
     protected final DocValueFormat format;
     @Nullable
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SortedDocsProducer.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SortedDocsProducer.java
index 9fe92c5f8d7fa..bd0a4f13ddf08 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SortedDocsProducer.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/SortedDocsProducer.java
@@ -40,6 +40,7 @@
 import org.apache.lucene.util.DocIdSetBuilder;
 import org.opensearch.common.Nullable;
 import org.opensearch.search.aggregations.LeafBucketCollector;
+import org.opensearch.search.aggregations.bucket.DocCountProvider;
 
 import java.io.IOException;
 
@@ -47,6 +48,8 @@
  * A producer that visits composite buckets in the order of the value indexed in the leading source of the composite
  * definition. It can be used to control which documents should be collected to produce the top composite buckets
  * without visiting all documents in an index.
+ *
+ * @opensearch.internal
  */
 abstract class SortedDocsProducer {
     protected final String field;
@@ -72,6 +75,8 @@ protected boolean processBucket(
     ) throws IOException {
         final int[] topCompositeCollected = new int[1];
         final boolean[] hasCollected = new boolean[1];
+        final DocCountProvider docCountProvider = new DocCountProvider();
+        docCountProvider.setLeafReaderContext(context);
         final LeafBucketCollector queueCollector = new LeafBucketCollector() {
             int lastDoc = -1;
 
@@ -84,7 +89,8 @@ protected boolean processBucket(
             @Override
             public void collect(int doc, long bucket) throws IOException {
                 hasCollected[0] = true;
-                if (queue.addIfCompetitive()) {
+                long docCount = docCountProvider.getDocCount(doc);
+                if (queue.addIfCompetitive(docCount)) {
                     topCompositeCollected[0]++;
                     if (adder != null && doc != lastDoc) {
                         if (remainingBits == 0) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsSortedDocsProducer.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsSortedDocsProducer.java
index c977ba3c7ecdb..89e7f4fae1321 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsSortedDocsProducer.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsSortedDocsProducer.java
@@ -45,6 +45,8 @@
 
 /**
  * A {@link SortedDocsProducer} that can sort documents based on terms indexed in the provided field.
+ *
+ * @opensearch.internal
  */
 class TermsSortedDocsProducer extends SortedDocsProducer {
     TermsSortedDocsProducer(String field) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsValuesSourceBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsValuesSourceBuilder.java
index c871e8d0c7d5b..f82e0efc4c31e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsValuesSourceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/TermsValuesSourceBuilder.java
@@ -34,12 +34,12 @@
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.search.DocValueFormat;
@@ -52,15 +52,22 @@
 import org.opensearch.search.sort.SortOrder;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.function.LongConsumer;
 import java.util.function.LongUnaryOperator;
 
 /**
  * A {@link CompositeValuesSourceBuilder} that builds a {@link ValuesSource} from a {@link Script} or
  * a field name.
+ *
+ * @opensearch.internal
  */
 public class TermsValuesSourceBuilder extends CompositeValuesSourceBuilder<TermsValuesSourceBuilder> {
-
+    /**
+     * Composite supplier for terms
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface TermsCompositeSupplier {
         CompositeValuesSourceConfig apply(
@@ -112,7 +119,7 @@ public String type() {
     static void register(ValuesSourceRegistry.Builder builder) {
         builder.register(
             REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.DATE, CoreValuesSourceType.NUMERIC, CoreValuesSourceType.BOOLEAN),
             (valuesSourceConfig, name, hasScript, format, missingBucket, missingOrder, order) -> {
                 final DocValueFormat docValueFormat;
                 if (format == null && valuesSourceConfig.valueSourceType() == CoreValuesSourceType.DATE) {
@@ -150,6 +157,17 @@ static void register(ValuesSourceRegistry.Builder builder) {
                                 compositeValuesSourceConfig.reverseMul()
                             );
 
+                        } else if (vs.isBigInteger()) {
+                            return new UnsignedLongValuesSource(
+                                bigArrays,
+                                compositeValuesSourceConfig.fieldType(),
+                                vs::longValues,
+                                compositeValuesSourceConfig.format(),
+                                compositeValuesSourceConfig.missingBucket(),
+                                compositeValuesSourceConfig.missingOrder(),
+                                size,
+                                compositeValuesSourceConfig.reverseMul()
+                            );
                         } else {
                             final LongUnaryOperator rounding;
                             rounding = LongUnaryOperator.identity();
@@ -174,7 +192,7 @@ static void register(ValuesSourceRegistry.Builder builder) {
 
         builder.register(
             REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.BYTES, CoreValuesSourceType.IP),
+            List.of(CoreValuesSourceType.BYTES, CoreValuesSourceType.IP),
             (valuesSourceConfig, name, hasScript, format, missingBucket, missingOrder, order) -> new CompositeValuesSourceConfig(
                 name,
                 valuesSourceConfig.fieldType(),
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongPointsSortedDocsProducer.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongPointsSortedDocsProducer.java
new file mode 100644
index 0000000000000..f391eb4f51169
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongPointsSortedDocsProducer.java
@@ -0,0 +1,186 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.composite;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.PointValues;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
+import org.apache.lucene.search.CollectionTerminatedException;
+import org.apache.lucene.search.DocIdSet;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.util.DocIdSetBuilder;
+import org.opensearch.common.Numbers;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.Arrays;
+
+/**
+ * A {@link SortedDocsProducer} that can sort documents based on numerics indexed for unsigned long field.
+ *
+ * @opensearch.internal
+ */
+class UnsignedLongPointsSortedDocsProducer extends SortedDocsProducer {
+    private final byte[] lowerPointQuery;
+    private final byte[] upperPointQuery;
+
+    UnsignedLongPointsSortedDocsProducer(String field, byte[] lowerPointQuery, byte[] upperPointQuery) {
+        super(field);
+        this.lowerPointQuery = lowerPointQuery;
+        this.upperPointQuery = upperPointQuery;
+    }
+
+    @Override
+    DocIdSet processLeaf(Query query, CompositeValuesCollectorQueue queue, LeafReaderContext context, boolean fillDocIdSet)
+        throws IOException {
+        final PointValues values = context.reader().getPointValues(field);
+        if (values == null) {
+            // no value for the field
+            return DocIdSet.EMPTY;
+        }
+        BigInteger lowerBucket = Numbers.MIN_UNSIGNED_LONG_VALUE;
+        Comparable<?> lowerValue = queue.getLowerValueLeadSource();
+        if (lowerValue != null) {
+            if (lowerValue.getClass() != BigInteger.class) {
+                throw new IllegalStateException("expected BigInteger, got " + lowerValue.getClass());
+            }
+            lowerBucket = (BigInteger) lowerValue;
+        }
+
+        BigInteger upperBucket = Numbers.MAX_UNSIGNED_LONG_VALUE;
+        Comparable<?> upperValue = queue.getUpperValueLeadSource();
+        if (upperValue != null) {
+            if (upperValue.getClass() != BigInteger.class) {
+                throw new IllegalStateException("expected BigInteger, got " + upperValue.getClass());
+            }
+            upperBucket = (BigInteger) upperValue;
+        }
+        DocIdSetBuilder builder = fillDocIdSet ? new DocIdSetBuilder(context.reader().maxDoc(), values, field) : null;
+        Visitor visitor = new Visitor(
+            context,
+            queue,
+            builder,
+            values.getBytesPerDimension(),
+            lowerBucket.longValue(),
+            upperBucket.longValue()
+        );
+        try {
+            values.intersect(visitor);
+            visitor.flush();
+        } catch (CollectionTerminatedException exc) {}
+        return fillDocIdSet ? builder.build() : DocIdSet.EMPTY;
+    }
+
+    private class Visitor implements PointValues.IntersectVisitor {
+        final LeafReaderContext context;
+        final CompositeValuesCollectorQueue queue;
+        final DocIdSetBuilder builder;
+        final int maxDoc;
+        final int bytesPerDim;
+        final long lowerBucket;
+        final long upperBucket;
+
+        DocIdSetBuilder bucketDocsBuilder;
+        DocIdSetBuilder.BulkAdder adder;
+        int remaining;
+        long lastBucket;
+        boolean first = true;
+
+        Visitor(
+            LeafReaderContext context,
+            CompositeValuesCollectorQueue queue,
+            DocIdSetBuilder builder,
+            int bytesPerDim,
+            long lowerBucket,
+            long upperBucket
+        ) {
+            this.context = context;
+            this.maxDoc = context.reader().maxDoc();
+            this.queue = queue;
+            this.builder = builder;
+            this.lowerBucket = lowerBucket;
+            this.upperBucket = upperBucket;
+            this.bucketDocsBuilder = new DocIdSetBuilder(maxDoc);
+            this.bytesPerDim = bytesPerDim;
+        }
+
+        @Override
+        public void grow(int count) {
+            remaining = count;
+            adder = bucketDocsBuilder.grow(count);
+        }
+
+        @Override
+        public void visit(int docID) throws IOException {
+            throw new IllegalStateException("should never be called");
+        }
+
+        @Override
+        public void visit(int docID, byte[] packedValue) throws IOException {
+            if (compare(packedValue, packedValue) != PointValues.Relation.CELL_CROSSES_QUERY) {
+                remaining--;
+                return;
+            }
+
+            long bucket = BigIntegerPoint.decodeDimension(packedValue, 0).longValue();
+            if (first == false && Long.compareUnsigned(bucket, lastBucket) != 0) {
+                final DocIdSet docIdSet = bucketDocsBuilder.build();
+                if (processBucket(queue, context, docIdSet.iterator(), lastBucket, builder) &&
+                // lower bucket is inclusive
+                    Long.compareUnsigned(lowerBucket, lastBucket) != 0) {
+                    // this bucket does not have any competitive composite buckets,
+                    // we can early terminate the collection because the remaining buckets are guaranteed
+                    // to be greater than this bucket.
+                    throw new CollectionTerminatedException();
+                }
+                bucketDocsBuilder = new DocIdSetBuilder(maxDoc);
+                assert remaining > 0;
+                adder = bucketDocsBuilder.grow(remaining);
+            }
+            lastBucket = bucket;
+            first = false;
+            adder.add(docID);
+            remaining--;
+        }
+
+        @Override
+        public PointValues.Relation compare(byte[] minPackedValue, byte[] maxPackedValue) {
+            if ((upperPointQuery != null && Arrays.compareUnsigned(minPackedValue, 0, bytesPerDim, upperPointQuery, 0, bytesPerDim) > 0)
+                || (lowerPointQuery != null
+                    && Arrays.compareUnsigned(maxPackedValue, 0, bytesPerDim, lowerPointQuery, 0, bytesPerDim) < 0)) {
+                // does not match the query
+                return PointValues.Relation.CELL_OUTSIDE_QUERY;
+            }
+
+            // check the current bounds
+            if (Long.compareUnsigned(lowerBucket, Numbers.MIN_UNSIGNED_LONG_VALUE_AS_LONG) != 0) {
+                long maxBucket = BigIntegerPoint.decodeDimension(maxPackedValue, 0).longValue();
+                if (Long.compareUnsigned(maxBucket, lowerBucket) < 0) {
+                    return PointValues.Relation.CELL_OUTSIDE_QUERY;
+                }
+            }
+
+            if (Long.compareUnsigned(upperBucket, Numbers.MAX_UNSIGNED_LONG_VALUE_AS_LONG) != 0) {
+                long minBucket = BigIntegerPoint.decodeDimension(minPackedValue, 0).longValue();
+                if (Long.compareUnsigned(minBucket, upperBucket) > 0) {
+                    return PointValues.Relation.CELL_OUTSIDE_QUERY;
+                }
+            }
+            return PointValues.Relation.CELL_CROSSES_QUERY;
+        }
+
+        public void flush() throws IOException {
+            if (first == false) {
+                final DocIdSet docIdSet = bucketDocsBuilder.build();
+                processBucket(queue, context, docIdSet.iterator(), lastBucket, builder);
+                bucketDocsBuilder = null;
+            }
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongValuesSource.java
new file mode 100644
index 0000000000000..797b61f46240e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongValuesSource.java
@@ -0,0 +1,220 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.composite;
+
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.search.PointRangeQuery;
+import org.apache.lucene.search.Query;
+import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.Numbers;
+import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.BitArray;
+import org.opensearch.common.util.LongArray;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.LeafBucketCollector;
+import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.Objects;
+
+/**
+ * A {@link SingleDimensionValuesSource} for unsigned longs.
+ *
+ * @opensearch.internal
+ */
+public class UnsignedLongValuesSource extends SingleDimensionValuesSource<BigInteger> {
+    private final BigArrays bigArrays;
+    private final CheckedFunction<LeafReaderContext, SortedNumericDocValues, IOException> docValuesFunc;
+
+    private BitArray bits;
+    private LongArray values;
+    private long currentValue;
+    private boolean missingCurrentValue;
+
+    public UnsignedLongValuesSource(
+        BigArrays bigArrays,
+        MappedFieldType fieldType,
+        CheckedFunction<LeafReaderContext, SortedNumericDocValues, IOException> docValuesFunc,
+        DocValueFormat format,
+        boolean missingBucket,
+        MissingOrder missingOrder,
+        int size,
+        int reverseMul
+    ) {
+        super(bigArrays, format, fieldType, missingBucket, missingOrder, size, reverseMul);
+        this.bigArrays = bigArrays;
+        this.docValuesFunc = docValuesFunc;
+        this.bits = missingBucket ? new BitArray(Math.min(size, 100), bigArrays) : null;
+        this.values = bigArrays.newLongArray(Math.min(size, 100), false);
+    }
+
+    @Override
+    void copyCurrent(int slot) {
+        values = bigArrays.grow(values, slot + 1);
+        if (missingBucket && missingCurrentValue) {
+            bits.clear(slot);
+        } else {
+            assert missingCurrentValue == false;
+            if (missingBucket) {
+                bits.set(slot);
+            }
+            values.set(slot, currentValue);
+        }
+    }
+
+    @Override
+    int compare(int from, int to) {
+        if (missingBucket) {
+            int result = missingOrder.compare(() -> bits.get(from) == false, () -> bits.get(to) == false, reverseMul);
+            if (MissingOrder.unknownOrder(result) == false) {
+                return result;
+            }
+        }
+        return compareValues(values.get(from), values.get(to));
+    }
+
+    @Override
+    int compareCurrent(int slot) {
+        if (missingBucket) {
+            int result = missingOrder.compare(() -> missingCurrentValue, () -> bits.get(slot) == false, reverseMul);
+            if (MissingOrder.unknownOrder(result) == false) {
+                return result;
+            }
+        }
+        return compareValues(currentValue, values.get(slot));
+    }
+
+    @Override
+    int compareCurrentWithAfter() {
+        if (missingBucket) {
+            int result = missingOrder.compare(() -> missingCurrentValue, () -> Objects.isNull(afterValue), reverseMul);
+            if (MissingOrder.unknownOrder(result) == false) {
+                return result;
+            }
+        }
+        return compareValues(currentValue, afterValue.longValue());
+    }
+
+    @Override
+    int hashCode(int slot) {
+        if (missingBucket && bits.get(slot) == false) {
+            return 0;
+        } else {
+            return Long.hashCode(values.get(slot));
+        }
+    }
+
+    @Override
+    int hashCodeCurrent() {
+        if (missingCurrentValue) {
+            return 0;
+        } else {
+            return Long.hashCode(currentValue);
+        }
+    }
+
+    @Override
+    protected void setAfter(Comparable value) {
+        if (missingBucket && value == null) {
+            afterValue = null;
+        } else {
+            // parse the value from a string in case it is a date or a formatted unsigned long.
+            afterValue = format.parseUnsignedLong(value.toString(), false, () -> {
+                throw new IllegalArgumentException("now() is not supported in [after] key");
+            });
+        }
+    }
+
+    @Override
+    BigInteger toComparable(int slot) {
+        if (missingBucket && bits.get(slot) == false) {
+            return null;
+        }
+        return Numbers.toUnsignedBigInteger(values.get(slot));
+    }
+
+    @Override
+    LeafBucketCollector getLeafCollector(LeafReaderContext context, LeafBucketCollector next) throws IOException {
+        final SortedNumericDocValues dvs = docValuesFunc.apply(context);
+        return new LeafBucketCollector() {
+            @Override
+            public void collect(int doc, long bucket) throws IOException {
+                if (dvs.advanceExact(doc)) {
+                    int num = dvs.docValueCount();
+                    for (int i = 0; i < num; i++) {
+                        currentValue = dvs.nextValue();
+                        missingCurrentValue = false;
+                        next.collect(doc, bucket);
+                    }
+                } else if (missingBucket) {
+                    missingCurrentValue = true;
+                    next.collect(doc, bucket);
+                }
+            }
+        };
+    }
+
+    @Override
+    LeafBucketCollector getLeafCollector(Comparable value, LeafReaderContext context, LeafBucketCollector next) {
+        // We still accept long here (not BigInteger)
+        if (value.getClass() != Long.class) {
+            throw new IllegalArgumentException("Expected Long, got " + value.getClass());
+        }
+        currentValue = (Long) value;
+        return new LeafBucketCollector() {
+            @Override
+            public void collect(int doc, long bucket) throws IOException {
+                next.collect(doc, bucket);
+            }
+        };
+    }
+
+    @Override
+    public void close() {
+        Releasables.close(values, bits);
+    }
+
+    private int compareValues(long v1, long v2) {
+        return Long.compareUnsigned(v1, v2) * reverseMul;
+    }
+
+    @Override
+    SortedDocsProducer createSortedDocsProducerOrNull(IndexReader reader, Query query) {
+        query = LongValuesSource.extractQuery(query);
+        if (checkIfSortedDocsIsApplicable(reader, fieldType) == false
+            || LongValuesSource.checkMatchAllOrRangeQuery(query, fieldType.name()) == false) {
+            return null;
+        }
+        final byte[] lowerPoint;
+        final byte[] upperPoint;
+        if (query instanceof PointRangeQuery) {
+            final PointRangeQuery rangeQuery = (PointRangeQuery) query;
+            lowerPoint = rangeQuery.getLowerPoint();
+            upperPoint = rangeQuery.getUpperPoint();
+        } else {
+            lowerPoint = null;
+            upperPoint = null;
+        }
+
+        if (fieldType instanceof NumberFieldMapper.NumberFieldType) {
+            NumberFieldMapper.NumberFieldType ft = (NumberFieldMapper.NumberFieldType) fieldType;
+            if (ft.typeName() == "unsigned_long") {
+                return new UnsignedLongPointsSortedDocsProducer(fieldType.name(), lowerPoint, upperPoint);
+            }
+        }
+
+        return null;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/package-info.java
new file mode 100644
index 0000000000000..33a87b342d74d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/composite/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Composite Aggregation package. */
+package org.opensearch.search.aggregations.bucket.composite;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filter.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filter.java
index 44ccea1204fdb..213e76f19c535 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filter.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filter.java
@@ -35,5 +35,7 @@
 
 /**
  * A {@code filter} aggregation. Defines a single bucket that holds all documents that match a specific filter.
+ *
+ * @opensearch.internal
  */
 public interface Filter extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregationBuilder.java
index 58c47fa3e5c5b..586283fca6b63 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -51,6 +51,11 @@
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * Aggregation Builder for filter agg
+ *
+ * @opensearch.internal
+ */
 public class FilterAggregationBuilder extends AbstractAggregationBuilder<FilterAggregationBuilder> {
     public static final String NAME = "filter";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregator.java
index 28bfb6071332c..0f73d3453b658 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregator.java
@@ -51,6 +51,8 @@
 
 /**
  * Aggregate all docs that match a filter.
+ *
+ * @opensearch.internal
  */
 public class FilterAggregator extends BucketsAggregator implements SingleBucketAggregator {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorFactory.java
index 07823f19e34b5..55c841f5b9c04 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorFactory.java
@@ -48,6 +48,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for filter agg
+ *
+ * @opensearch.internal
+ */
 public class FilterAggregatorFactory extends AggregatorFactory {
 
     private Weight weight;
@@ -96,4 +101,8 @@ public Aggregator createInternal(
         return new FilterAggregator(name, () -> this.getWeight(), factories, searchContext, parent, cardinality, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filters.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filters.java
index b70cbd2586ebc..25153eb86d1d8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filters.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/Filters.java
@@ -39,6 +39,8 @@
 /**
  * A multi bucket aggregation where the buckets are defined by a set of filters (a bucket per filter). Each bucket
  * will collect all documents matching its filter.
+ *
+ * @opensearch.internal
  */
 public interface Filters extends MultiBucketsAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
index a1a5d53bf2b30..125cbf5d533c7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -59,6 +59,11 @@
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * Aggregation Builder for filters agg
+ *
+ * @opensearch.internal
+ */
 public class FiltersAggregationBuilder extends AbstractAggregationBuilder<FiltersAggregationBuilder> {
     public static final String NAME = "filters";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregator.java
index e13a3c7557685..7b86d0ed15cf8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregator.java
@@ -35,13 +35,13 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.Bits;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -60,12 +60,22 @@
 import java.util.Objects;
 import java.util.function.Supplier;
 
+/**
+ * Aggregate all docs that match multiple filters.
+ *
+ * @opensearch.internal
+ */
 public class FiltersAggregator extends BucketsAggregator {
 
     public static final ParseField FILTERS_FIELD = new ParseField("filters");
     public static final ParseField OTHER_BUCKET_FIELD = new ParseField("other_bucket");
     public static final ParseField OTHER_BUCKET_KEY_FIELD = new ParseField("other_bucket_key");
 
+    /**
+     * Keyed filter for the filters agg
+     *
+     * @opensearch.internal
+     */
     public static class KeyedFilter implements Writeable, ToXContentFragment {
         private final String key;
         private final QueryBuilder filter;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorFactory.java
index 50125c4cc50b0..35d968b789a21 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorFactory.java
@@ -49,11 +49,16 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for filters agg
+ *
+ * @opensearch.internal
+ */
 public class FiltersAggregatorFactory extends AggregatorFactory {
 
     private final String[] keys;
     private final Query[] filters;
-    private Weight[] weights;
+    private volatile Weight[] weights;
     private final boolean keyed;
     private final boolean otherBucket;
     private final String otherBucketKey;
@@ -88,19 +93,33 @@ public FiltersAggregatorFactory(
      * created if the aggregation collects documents reducing the overhead of
      * the aggregation in the case where no documents are collected.
      *
-     * Note that as aggregations are initialsed and executed in a serial manner,
-     * no concurrency considerations are necessary here.
+     * Note: With concurrent segment search use case, multiple aggregation collectors executing
+     * on different threads will try to fetch the weights. To handle the race condition there is
+     * a synchronization block
      */
     public Weight[] getWeights(SearchContext searchContext) {
-        if (weights == null) {
-            try {
-                IndexSearcher contextSearcher = searchContext.searcher();
-                weights = new Weight[filters.length];
-                for (int i = 0; i < filters.length; ++i) {
-                    this.weights[i] = contextSearcher.createWeight(contextSearcher.rewrite(filters[i]), ScoreMode.COMPLETE_NO_SCORES, 1);
+        if (weights != null) {
+            return weights;
+        }
+
+        // This will happen only for the first segment access in the slices. After that for other segments
+        // weights will be non-null and returned from above
+        synchronized (this) {
+            if (weights == null) {
+                try {
+                    final Weight[] filterWeights = new Weight[filters.length];
+                    IndexSearcher contextSearcher = searchContext.searcher();
+                    for (int i = 0; i < filters.length; ++i) {
+                        filterWeights[i] = contextSearcher.createWeight(
+                            contextSearcher.rewrite(filters[i]),
+                            ScoreMode.COMPLETE_NO_SCORES,
+                            1
+                        );
+                    }
+                    weights = filterWeights;
+                } catch (IOException e) {
+                    throw new AggregationInitializationException("Failed to initialze filters for aggregation [" + name() + "]", e);
                 }
-            } catch (IOException e) {
-                throw new AggregationInitializationException("Failed to initialse filters for aggregation [" + name() + "]", e);
             }
         }
         return weights;
@@ -127,4 +146,8 @@ public Aggregator createInternal(
         );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilter.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilter.java
index fc408366a8333..61fe979be7910 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilter.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilter.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Implementation of filter agg
+ *
+ * @opensearch.internal
+ */
 public class InternalFilter extends InternalSingleBucketAggregation implements Filter {
     InternalFilter(String name, long docCount, InternalAggregations subAggregations, Map<String, Object> metadata) {
         super(name, docCount, subAggregations, metadata);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilters.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilters.java
index 3989400bb4958..104dab01d90fe 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilters.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/InternalFilters.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -47,7 +47,17 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of filters agg
+ *
+ * @opensearch.internal
+ */
 public class InternalFilters extends InternalMultiBucketAggregation<InternalFilters, InternalFilters.InternalBucket> implements Filters {
+    /**
+     * Internal bucket for an internal filters agg
+     *
+     * @opensearch.internal
+     */
     public static class InternalBucket extends InternalMultiBucketAggregation.InternalBucket implements Filters.Bucket {
 
         private final boolean keyed;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilter.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilter.java
index 1d922949d9983..984dbaf3b3602 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilter.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilter.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A filter agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedFilter extends ParsedSingleBucketAggregation implements Filter {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilters.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilters.java
index bcecac0ac0350..71e7f0ecbb730 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilters.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/ParsedFilters.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.filter;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -46,8 +46,13 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * A filters agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedFilters extends ParsedMultiBucketAggregation<ParsedFilters.ParsedBucket> implements Filters {
 
     private Map<String, ParsedBucket> bucketMap;
@@ -101,6 +106,11 @@ public static ParsedFilters fromXContent(XContentParser parser, String name) thr
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for the parsed filters agg
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Filters.Bucket {
 
         private String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/package-info.java
new file mode 100644
index 0000000000000..112f2f3221858
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/filter/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** filter Aggregation package. */
+package org.opensearch.search.aggregations.bucket.filter;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/Global.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/Global.java
index 4a5a484ea7565..9481d134adcb5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/Global.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/Global.java
@@ -35,5 +35,7 @@
 
 /**
  * A {@code global} aggregation. Defines a single bucket the holds all the documents in the search context.
+ *
+ * @opensearch.internal
  */
 public interface Global extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregationBuilder.java
index ad3498043c538..5404dfe91f9d1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.global;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -45,6 +45,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for global agg
+ *
+ * @opensearch.internal
+ */
 public class GlobalAggregationBuilder extends AbstractAggregationBuilder<GlobalAggregationBuilder> {
     public static GlobalAggregationBuilder parse(XContentParser parser, String aggregationName) throws IOException {
         parser.nextToken();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregator.java
index 7b3c9399225ae..96cf8f8f7664a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregator.java
@@ -44,6 +44,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs from the global search scope.
+ *
+ * @opensearch.internal
+ */
 public class GlobalAggregator extends BucketsAggregator implements SingleBucketAggregator {
 
     public GlobalAggregator(String name, AggregatorFactories subFactories, SearchContext aggregationContext, Map<String, Object> metadata)
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregatorFactory.java
index 102e1befb0822..47de1fcda29c9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/GlobalAggregatorFactory.java
@@ -43,6 +43,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for global agg
+ *
+ * @opensearch.internal
+ */
 public class GlobalAggregatorFactory extends AggregatorFactory {
 
     public GlobalAggregatorFactory(
@@ -77,4 +82,9 @@ public Aggregator createInternal(
         }
         return new GlobalAggregator(name, factories, searchContext, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/InternalGlobal.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/InternalGlobal.java
index 20f49e4ce00df..feed446b23e21 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/InternalGlobal.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/InternalGlobal.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.bucket.global;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
@@ -41,6 +41,8 @@
 /**
  * A global scope get (the document set on which we aggregate is all documents in the search context (ie. index + type)
  * regardless the query.
+ *
+ * @opensearch.internal
  */
 public class InternalGlobal extends InternalSingleBucketAggregation implements Global {
     InternalGlobal(String name, long docCount, InternalAggregations aggregations, Map<String, Object> metadata) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/ParsedGlobal.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/ParsedGlobal.java
index 2e97e76ad3e28..2e8f07dd1f19a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/ParsedGlobal.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/ParsedGlobal.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.global;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A global agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGlobal extends ParsedSingleBucketAggregation implements Global {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/global/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/package-info.java
new file mode 100644
index 0000000000000..b278c91af36ea
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/global/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Global Aggregation package. */
+package org.opensearch.search.aggregations.bucket.global;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AbstractHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AbstractHistogramAggregator.java
index adf3d973a2621..d3a4a51e5b6f2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AbstractHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AbstractHistogramAggregator.java
@@ -55,6 +55,8 @@
 /**
  * Base class for functionality shared between aggregators for this
  * {@code histogram} aggregation.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractHistogramAggregator extends BucketsAggregator {
     protected final DocValueFormat formatter;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregationBuilder.java
index a9f5339ad4fdb..d4d26de15615b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregationBuilder.java
@@ -33,14 +33,14 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
@@ -60,6 +60,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for auto_gate_histogram agg
+ *
+ * @opensearch.internal
+ */
 public class AutoDateHistogramAggregationBuilder extends ValuesSourceAggregationBuilder<AutoDateHistogramAggregationBuilder> {
 
     public static final String NAME = "auto_date_histogram";
@@ -281,6 +286,11 @@ public boolean equals(Object obj) {
         return Objects.equals(numBuckets, other.numBuckets) && Objects.equals(minimumIntervalExpression, other.minimumIntervalExpression);
     }
 
+    /**
+     * Round off information
+     *
+     * @opensearch.internal
+     */
     public static class RoundingInfo implements Writeable {
         final Rounding rounding;
         final int[] innerIntervals;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregator.java
index 76812334ff235..d7f89225524c0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregator.java
@@ -38,9 +38,9 @@
 import org.opensearch.common.Rounding;
 import org.opensearch.common.Rounding.Prepared;
 import org.opensearch.common.lease.Releasables;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.IntArray;
 import org.opensearch.common.util.LongArray;
+import org.opensearch.core.common.util.ByteArray;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -76,6 +76,8 @@
  * standpoint but the simpler implementation is between 7% and 15% faster
  * when you can use it. This is an important aggregation and we need that
  * performance.
+ *
+ * @opensearch.internal
  */
 abstract class AutoDateHistogramAggregator extends DeferableBucketAggregator {
     static AutoDateHistogramAggregator build(
@@ -241,6 +243,8 @@ protected final void merge(long[] mergeMap, long newNumBuckets) {
      * rebucket roughly {@code O(log number_of_hits_collected_so_far)} because
      * the "shape" of the roundings is <strong>roughly</strong>
      * logarithmically increasing.
+     *
+     * @opensearch.internal
      */
     private static class FromSingle extends AutoDateHistogramAggregator {
         private int roundingIdx;
@@ -404,6 +408,8 @@ protected void doClose() {
      * rounding all of the keys for {@code owningBucketOrd} that we're going to
      * collect and picking the rounding based on a real, accurate count and the
      * min and max.
+     *
+     * @opensearch.internal
      */
     private static class FromMany extends AutoDateHistogramAggregator {
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorFactory.java
index 3cb2a3a7d0962..059b88c9475ed 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorFactory.java
@@ -50,6 +50,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Aggregation Factory for auto_date_histogram
+ *
+ * @opensearch.internal
+ */
 public final class AutoDateHistogramAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -119,4 +124,9 @@ protected Aggregator createUnmapped(SearchContext searchContext, Aggregator pare
             metadata
         );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorSupplier.java
index fe48c4ba95307..a9b62019bdeb5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorSupplier.java
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Aggregator supplier interface for auto_date_histogram agg
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface AutoDateHistogramAggregatorSupplier {
     Aggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationBuilder.java
index c416f6657b9ea..210a605627def 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationBuilder.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -65,6 +65,8 @@
 
 /**
  * A builder for histograms on date fields.
+ *
+ * @opensearch.internal
  */
 public class DateHistogramAggregationBuilder extends ValuesSourceAggregationBuilder<DateHistogramAggregationBuilder>
     implements
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationSupplier.java
index dab69e86e4173..146eeedfbe933 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregationSupplier.java
@@ -44,6 +44,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for date_histogram agg
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface DateHistogramAggregationSupplier {
     Aggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregator.java
index d243c46a7a136..8233c3d995dda 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregator.java
@@ -41,8 +41,8 @@
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
-import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.LeafBucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollectorBase;
@@ -62,6 +62,8 @@
  * {@link Rounding}.
  *
  * @see Rounding
+ *
+ * @opensearch.internal
  */
 class DateHistogramAggregator extends BucketsAggregator implements SizedBucketAggregator {
 
@@ -160,34 +162,29 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
 
     @Override
     public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
-        return buildAggregationsForVariableBuckets(
-            owningBucketOrds,
-            bucketOrds,
-            (bucketValue, docCount, subAggregationResults) -> {
-                return new InternalDateHistogram.Bucket(bucketValue, docCount, keyed, formatter, subAggregationResults);
-            },
-            (owningBucketOrd, buckets) -> {
-                // the contract of the histogram aggregation is that shards must return buckets ordered by key in ascending order
-                CollectionUtil.introSort(buckets, BucketOrder.key(true).comparator());
-
-                // value source will be null for unmapped fields
-                // Important: use `rounding` here, not `shardRounding`
-                InternalDateHistogram.EmptyBucketInfo emptyBucketInfo = minDocCount == 0
-                    ? new InternalDateHistogram.EmptyBucketInfo(rounding.withoutOffset(), buildEmptySubAggregations(), extendedBounds)
-                    : null;
-                return new InternalDateHistogram(
-                    name,
-                    buckets,
-                    order,
-                    minDocCount,
-                    rounding.offset(),
-                    emptyBucketInfo,
-                    formatter,
-                    keyed,
-                    metadata()
-                );
-            }
-        );
+        return buildAggregationsForVariableBuckets(owningBucketOrds, bucketOrds, (bucketValue, docCount, subAggregationResults) -> {
+            return new InternalDateHistogram.Bucket(bucketValue, docCount, keyed, formatter, subAggregationResults);
+        }, (owningBucketOrd, buckets) -> {
+            // the contract of the histogram aggregation is that shards must return buckets ordered by key in ascending order
+            CollectionUtil.introSort(buckets, BucketOrder.key(true).comparator());
+
+            // value source will be null for unmapped fields
+            // Important: use `rounding` here, not `shardRounding`
+            InternalDateHistogram.EmptyBucketInfo emptyBucketInfo = minDocCount == 0
+                ? new InternalDateHistogram.EmptyBucketInfo(rounding.withoutOffset(), buildEmptySubAggregations(), extendedBounds)
+                : null;
+            return new InternalDateHistogram(
+                name,
+                buckets,
+                order,
+                minDocCount,
+                rounding.offset(),
+                emptyBucketInfo,
+                formatter,
+                keyed,
+                metadata()
+            );
+        });
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorFactory.java
index 900262aaa10a2..807ec1ab4e4b7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorFactory.java
@@ -33,7 +33,6 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.common.Rounding;
-import org.opensearch.common.collect.List;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -47,8 +46,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for date_histogram agg
+ *
+ * @opensearch.internal
+ */
 public final class DateHistogramAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -143,4 +148,9 @@ protected Aggregator createUnmapped(SearchContext searchContext, Aggregator pare
             metadata
         );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramInterval.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramInterval.java
index f3d3a56785931..8f8e71f3cd685 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramInterval.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramInterval.java
@@ -33,19 +33,21 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.common.Rounding;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * The interval the date histogram is based on.
+ *
+ * @opensearch.internal
  */
 public class DateHistogramInterval implements Writeable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalConsumer.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalConsumer.java
index 79581fd31375c..a2c63cf25c0c2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalConsumer.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalConsumer.java
@@ -37,6 +37,8 @@
  *
  * Provides definitions for the new fixed and calendar intervals, and deprecated
  * defintions for the old interval/dateHisto interval parameters
+ *
+ * @opensearch.internal
  */
 public interface DateIntervalConsumer<T> {
     @Deprecated
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
index fb1287ac1716c..a7faacbf517aa 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
@@ -33,19 +33,19 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.Rounding;
 import org.opensearch.common.Rounding.DateTimeUnit;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.time.ZoneId;
@@ -64,6 +64,8 @@
  * After the deprecated parameters are removed, this class can be simplified greatly.  The legacy options
  * will be removed, and the mutual-exclusion checks can be done in the setters directly removing the need
  * for the enum and the complicated "state machine" logic
+ *
+ * @opensearch.internal
  */
 public class DateIntervalWrapper implements ToXContentFragment, Writeable {
     private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(DateHistogramAggregationBuilder.class);
@@ -73,6 +75,11 @@ public class DateIntervalWrapper implements ToXContentFragment, Writeable {
     private static final ParseField FIXED_INTERVAL_FIELD = new ParseField("fixed_interval");
     private static final ParseField CALENDAR_INTERVAL_FIELD = new ParseField("calendar_interval");
 
+    /**
+     * The type of interval
+     *
+     * @opensearch.internal
+     */
     public enum IntervalTypeEnum implements Writeable {
         NONE,
         FIXED,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregator.java
index d81ac0ae44ac8..f70a5bb537300 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregator.java
@@ -69,6 +69,8 @@
  * {@link Rounding}.
  *
  * @see Rounding
+ *
+ * @opensearch.internal
  */
 class DateRangeHistogramAggregator extends BucketsAggregator {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBounds.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBounds.java
index a822976517910..69c70ed1bf7fd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBounds.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBounds.java
@@ -32,26 +32,28 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.InstantiatingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.InstantiatingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Represent hard_bounds and extended_bounds in histogram aggregations.
  *
  * This class is similar to {@link LongBounds} used in date histograms, but is using longs to store data. LongBounds and DoubleBounds are
  * not used interchangeably and therefore don't share any common interfaces except for serialization.
+ *
+ * @opensearch.internal
  */
 
 public class DoubleBounds implements ToXContentFragment, Writeable {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/Histogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/Histogram.java
index 85c53243f41a4..c19eadebf7954 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/Histogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/Histogram.java
@@ -31,13 +31,15 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 
 import java.util.List;
 
 /**
  * A {@code histogram} aggregation. Defines multiple buckets, each representing an interval in a histogram.
+ *
+ * @opensearch.internal
  */
 public interface Histogram extends MultiBucketsAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregationBuilder.java
index 1ca2988a3e7c0..83f223c094632 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregationBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -60,6 +60,8 @@
 /**
  * A builder for histograms on numeric fields.  This builder can operate on either base numeric fields, or numeric range fields.  IP range
  * fields are unsupported, and will throw at the factory layer.
+ *
+ * @opensearch.internal
  */
 public class HistogramAggregationBuilder extends ValuesSourceAggregationBuilder<HistogramAggregationBuilder> {
     public static final String NAME = "histogram";
@@ -225,12 +227,12 @@ public HistogramAggregationBuilder offset(double offset) {
 
     /** Get the current minimum bound that is set on this builder. */
     public double minBound() {
-        return extendedBounds.getMin();
+        return DoubleBounds.getEffectiveMin(extendedBounds);
     }
 
     /** Get the current maximum bound that is set on this builder. */
     public double maxBound() {
-        return extendedBounds.getMax();
+        return DoubleBounds.getEffectiveMax(extendedBounds);
     }
 
     protected DoubleBounds extendedBounds() {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorFactory.java
index 4978998e0824b..7506dcde23641 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorFactory.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.collect.List;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -46,11 +45,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
 /**
  * Constructs the per-shard aggregator instance for histogram aggregation.  Selects the numeric or range field implementation based on the
  * field type.
+ *
+ * @opensearch.internal
  */
 public final class HistogramAggregatorFactory extends ValuesSourceAggregatorFactory {
 
@@ -147,4 +149,9 @@ protected Aggregator createUnmapped(SearchContext searchContext, Aggregator pare
             metadata
         );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorSupplier.java
index 68af0b10c122d..4462605209775 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramAggregatorSupplier.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for histogram aggs
+ *
+ * @opensearch.internal
+ */
 public interface HistogramAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramFactory.java
index d5566f540b5d2..4488b5bd2206e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/HistogramFactory.java
@@ -38,7 +38,11 @@
 
 import java.util.List;
 
-/** Implemented by histogram aggregations and used by pipeline aggregations to insert buckets. */
+/**
+ * Implemented by histogram aggregations and used by pipeline aggregations to insert buckets.
+ *
+ * @opensearch.internal
+ */
 // public so that pipeline aggs can use this API: can we fix it?
 public interface HistogramFactory {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalAutoDateHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalAutoDateHistogram.java
index 83cd22934ab87..0866d26526761 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalAutoDateHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalAutoDateHistogram.java
@@ -33,9 +33,9 @@
 
 import org.apache.lucene.util.PriorityQueue;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -59,11 +59,18 @@
 
 /**
  * Implementation of {@link Histogram}.
+ *
+ * @opensearch.internal
  */
 public final class InternalAutoDateHistogram extends InternalMultiBucketAggregation<
     InternalAutoDateHistogram,
     InternalAutoDateHistogram.Bucket> implements Histogram, HistogramFactory {
 
+    /**
+     * Bucket for the internal auto date histogram agg
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Histogram.Bucket, KeyComparable<Bucket> {
 
         final long key;
@@ -155,6 +162,11 @@ public DocValueFormat getFormatter() {
         }
     }
 
+    /**
+     * Information about the bucket
+     *
+     * @opensearch.internal
+     */
     static class BucketInfo {
 
         final RoundingInfo[] roundingInfos;
@@ -420,6 +432,11 @@ protected Bucket reduceBucket(List<Bucket> buckets, ReduceContext context) {
         return new InternalAutoDateHistogram.Bucket(buckets.get(0).key, docCount, format, aggs);
     }
 
+    /**
+     * The result from a bucket reduce
+     *
+     * @opensearch.internal
+     */
     private static class BucketReduceResult {
         final List<Bucket> buckets;
         final int roundingIdx;
@@ -465,10 +482,7 @@ private BucketReduceResult addEmptyBuckets(BucketReduceResult current, ReduceCon
 
         Bucket lastBucket = null;
         ListIterator<Bucket> iter = list.listIterator();
-        InternalAggregations reducedEmptySubAggs = InternalAggregations.reduce(
-            org.opensearch.common.collect.List.of(bucketInfo.emptySubAggregations),
-            reduceContext
-        );
+        InternalAggregations reducedEmptySubAggs = InternalAggregations.reduce(List.of(bucketInfo.emptySubAggregations), reduceContext);
 
         // Add the empty buckets within the data,
         // e.g. if the data series is [1,2,3,7] there're 3 empty buckets that will be created for 4,5,6
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalDateHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalDateHistogram.java
index 9f26242e203a9..e0b6010c6c3e8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalDateHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalDateHistogram.java
@@ -34,9 +34,9 @@
 import org.apache.lucene.util.CollectionUtil;
 import org.apache.lucene.util.PriorityQueue;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -60,12 +60,19 @@
 
 /**
  * Implementation of {@link Histogram}.
+ *
+ * @opensearch.internal
  */
 public final class InternalDateHistogram extends InternalMultiBucketAggregation<InternalDateHistogram, InternalDateHistogram.Bucket>
     implements
         Histogram,
         HistogramFactory {
 
+    /**
+     * Bucket for an internal date histogram agg
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Histogram.Bucket, KeyComparable<Bucket> {
 
         final long key;
@@ -168,6 +175,11 @@ public boolean getKeyed() {
         }
     }
 
+    /**
+     * Information about an empty bucket
+     *
+     * @opensearch.internal
+     */
     static class EmptyBucketInfo {
 
         final Rounding rounding;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalHistogram.java
index 98e1aadd8c100..a27c689127ac9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalHistogram.java
@@ -33,9 +33,9 @@
 
 import org.apache.lucene.util.CollectionUtil;
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -57,11 +57,18 @@
 
 /**
  * Implementation of {@link Histogram}.
+ *
+ * @opensearch.internal
  */
 public final class InternalHistogram extends InternalMultiBucketAggregation<InternalHistogram, InternalHistogram.Bucket>
     implements
         Histogram,
         HistogramFactory {
+    /**
+     * Bucket for an internal histogram agg
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Histogram.Bucket, KeyComparable<Bucket> {
 
         final double key;
@@ -164,6 +171,11 @@ public boolean getKeyed() {
         }
     }
 
+    /**
+     * Information about an empty bucket
+     *
+     * @opensearch.internal
+     */
     public static class EmptyBucketInfo {
 
         final double interval, offset, minBound, maxBound;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogram.java
index 5a103771356d3..52f689eb7c229 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogram.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -53,12 +53,27 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregator supplier interface for an internal variable width histogram agg
+ *
+ * @opensearch.internal
+ */
 public class InternalVariableWidthHistogram extends InternalMultiBucketAggregation<
     InternalVariableWidthHistogram,
     InternalVariableWidthHistogram.Bucket> implements Histogram, HistogramFactory {
 
+    /**
+     * Bucket for an internal variable width histogram
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Histogram.Bucket, KeyComparable<Bucket> {
 
+        /**
+         * Bounds of the bucket
+         *
+         * @opensearch.internal
+         */
         public static class BucketBounds {
             public double min;
             public double max;
@@ -214,6 +229,11 @@ public DocValueFormat getFormatter() {
         }
     }
 
+    /**
+     * Information about an empty bucket
+     *
+     * @opensearch.internal
+     */
     static class EmptyBucketInfo {
 
         final InternalAggregations subAggregations;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/LongBounds.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/LongBounds.java
index 5e8087ef53e0e..e138824e7fce8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/LongBounds.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/LongBounds.java
@@ -33,30 +33,32 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Represent hard_bounds and extended_bounds in date-histogram aggregations.
  *
  * This class is similar to {@link DoubleBounds} used in histograms, but is using longs to store data. LongBounds and DoubleBounds are
  *  * not used interchangeably and therefore don't share any common interfaces except for serialization.
+ *
+ *  @opensearch.internal
  */
 public class LongBounds implements ToXContentFragment, Writeable {
     static final ParseField MIN_FIELD = new ParseField("min");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregator.java
index e6cddafc086a7..1cd44be431964 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregator.java
@@ -53,6 +53,8 @@
  * {@code offset} and {@code value}, it returns the highest number that can be
  * written as {@code interval * x + offset} and yet is less than or equal to
  * {@code value}.
+ *
+ * @opensearch.internal
  */
 public class NumericHistogramAggregator extends AbstractHistogramAggregator {
     private final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedAutoDateHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedAutoDateHistogram.java
index 671f2700ace36..cb27517d4e98b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedAutoDateHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedAutoDateHistogram.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
@@ -43,6 +43,11 @@
 import java.time.ZoneOffset;
 import java.util.List;
 
+/**
+ * A auto date histogram result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedAutoDateHistogram extends ParsedMultiBucketAggregation<ParsedAutoDateHistogram.ParsedBucket> implements Histogram {
 
     @Override
@@ -92,6 +97,11 @@ protected XContentBuilder doXContentBody(XContentBuilder builder, Params params)
         return builder;
     }
 
+    /**
+     * A parsed bucket for a parsed auto date histogram agg
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Histogram.Bucket {
 
         private Long key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedDateHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedDateHistogram.java
index efb681130ee66..def4081fb0f36 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedDateHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedDateHistogram.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
@@ -42,6 +42,11 @@
 import java.time.ZoneOffset;
 import java.util.List;
 
+/**
+ * A date histogram result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedDateHistogram extends ParsedMultiBucketAggregation<ParsedDateHistogram.ParsedBucket> implements Histogram {
 
     @Override
@@ -73,6 +78,11 @@ public static ParsedDateHistogram fromXContent(XContentParser parser, String nam
         return aggregation;
     }
 
+    /**
+     * Parsed Bucket for a parsed date histogram
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Histogram.Bucket {
 
         private Long key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedHistogram.java
index 354c95efa98f9..e9fe68ae2f614 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedHistogram.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
 
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * A histogram result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedHistogram extends ParsedMultiBucketAggregation<ParsedHistogram.ParsedBucket> implements Histogram {
 
     @Override
@@ -70,6 +75,11 @@ public static ParsedHistogram fromXContent(XContentParser parser, String name) t
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a parsed histogram
+     *
+     * @opensearch.internal
+     */
     static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Histogram.Bucket {
 
         private Double key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedVariableWidthHistogram.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedVariableWidthHistogram.java
index 727e34d3e7608..8b59f8af722ff 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedVariableWidthHistogram.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/ParsedVariableWidthHistogram.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -44,8 +44,13 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * A variable width histogram result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedVariableWidthHistogram extends ParsedMultiBucketAggregation<ParsedVariableWidthHistogram.ParsedBucket>
     implements
         Histogram {
@@ -79,6 +84,11 @@ public static ParsedVariableWidthHistogram fromXContent(XContentParser parser, S
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a parsed variable width histogram
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Histogram.Bucket {
         private Double key;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregator.java
index 919815c988fcc..fe77033f5a287 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregator.java
@@ -51,6 +51,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs that match a given range
+ *
+ * @opensearch.internal
+ */
 public class RangeHistogramAggregator extends AbstractHistogramAggregator {
     private final ValuesSource.Range valuesSource;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregator.java
index 21b085e297322..cfa154a6e9018 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregator.java
@@ -36,6 +36,8 @@
 
 /**
  * An aggregator capable of reporting bucket sizes in milliseconds. Used by RateAggregator for calendar-based buckets.
+ *
+ * @opensearch.internal
  */
 public interface SizedBucketAggregator {
     double bucketSize(long bucket, Rounding.DateTimeUnit unit);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregatorBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregatorBuilder.java
index 9edb76443f9a4..a87de32d0e18b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregatorBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/SizedBucketAggregatorBuilder.java
@@ -36,6 +36,8 @@
 
 /**
  * An aggregator capable of reporting bucket sizes in milliseconds. Used by RateAggregator for calendar-based buckets.
+ *
+ * @opensearch.internal
  */
 public interface SizedBucketAggregatorBuilder {
     double calendarDivider(TimeUnit timeUnit);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregationBuilder.java
index 169d219e76c42..94d88906b45ad 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -55,6 +55,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for variable_width_histogram agg
+ *
+ * @opensearch.internal
+ */
 public class VariableWidthHistogramAggregationBuilder extends ValuesSourceAggregationBuilder<VariableWidthHistogramAggregationBuilder> {
 
     public static final String NAME = "variable_width_histogram";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregator.java
index 2dc9d50e10015..11ff7dbc407cb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregator.java
@@ -66,6 +66,11 @@
 import java.util.function.Function;
 import java.util.function.LongUnaryOperator;
 
+/**
+ * Aggregate all docs that match variable width buckets.
+ *
+ * @opensearch.internal
+ */
 public class VariableWidthHistogramAggregator extends DeferableBucketAggregator {
 
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorFactory.java
index 644c41cc6f534..b846bf72ef4c5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for variable_width_histogram
+ *
+ * @opensearch.internal
+ */
 public class VariableWidthHistogramAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -111,4 +116,9 @@ protected Aggregator createUnmapped(SearchContext searchContext, Aggregator pare
             metadata
         );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorSupplier.java
index 80936ef0c27dc..153d7f1df7b41 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorSupplier.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for variable_width_histogram agg
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface VariableWidthHistogramAggregatorSupplier {
     Aggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/InternalMissing.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/InternalMissing.java
index a9aeda3f941cf..be71bbdeb2c04 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/InternalMissing.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/InternalMissing.java
@@ -31,13 +31,18 @@
 
 package org.opensearch.search.aggregations.bucket.missing;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Missing single bucket agg
+ *
+ * @opensearch.internal
+ */
 public class InternalMissing extends InternalSingleBucketAggregation implements Missing {
     InternalMissing(String name, long docCount, InternalAggregations aggregations, Map<String, Object> metadata) {
         super(name, docCount, aggregations, metadata);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/Missing.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/Missing.java
index 3f2a4197680e8..9918ae1f4b384 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/Missing.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/Missing.java
@@ -35,5 +35,7 @@
 
 /**
  * A {@code missing} aggregation. Defines a single bucket of all documents that are missing a specific field.
+ *
+ * @opensearch.internal
  */
 public interface Missing extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregationBuilder.java
index 75a74a02d3d4d..77e01d4e32093 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregationBuilder.java
@@ -33,10 +33,10 @@
 package org.opensearch.search.aggregations.bucket.missing;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -51,6 +51,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for missing agg
+ *
+ * @opensearch.internal
+ */
 public class MissingAggregationBuilder extends ValuesSourceAggregationBuilder<MissingAggregationBuilder> {
     public static final String NAME = "missing";
     public static final ValuesSourceRegistry.RegistryKey<MissingAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregator.java
index f189c3cf5e111..5f7b4b5a91e44 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregator.java
@@ -48,6 +48,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs that are missing a value.
+ *
+ * @opensearch.internal
+ */
 public class MissingAggregator extends BucketsAggregator implements SingleBucketAggregator {
 
     private final ValuesSource valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorFactory.java
index 37b3f784e8715..3032d695a3ee2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for missing agg
+ *
+ * @opensearch.internal
+ */
 public class MissingAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -80,4 +85,9 @@ protected MissingAggregator doCreateInternal(
             .getAggregator(MissingAggregationBuilder.REGISTRY_KEY, config)
             .build(name, factories, config, searchContext, parent, cardinality, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorSupplier.java
index 6b273514bb649..f9d99b1c7223a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorSupplier.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for missing agg
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface MissingAggregatorSupplier {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingOrder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingOrder.java
index 06086f507f665..dcdc838f31eec 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingOrder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/MissingOrder.java
@@ -9,15 +9,17 @@
 package org.opensearch.search.aggregations.bucket.missing;
 
 import org.opensearch.common.inject.Provider;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 
 /**
  * Composite Aggregation Missing bucket order.
+ *
+ * @opensearch.internal
  */
 public enum MissingOrder implements Writeable {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/ParsedMissing.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/ParsedMissing.java
index 1a4a88e69754f..b4dc431aaec6f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/ParsedMissing.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/ParsedMissing.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.missing;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A missing agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedMissing extends ParsedSingleBucketAggregation implements Missing {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/package-info.java
new file mode 100644
index 0000000000000..9e10d8fe090d7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/missing/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Missing Aggregation package. */
+package org.opensearch.search.aggregations.bucket.missing;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalNested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalNested.java
index a90134ebb8756..f4cdbf19f37cf 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalNested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalNested.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
@@ -40,6 +40,8 @@
 
 /**
  * Result of the {@link NestedAggregator}.
+ *
+ * @opensearch.internal
  */
 public class InternalNested extends InternalSingleBucketAggregation implements Nested {
     InternalNested(String name, long docCount, InternalAggregations aggregations, Map<String, Object> metadata) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalReverseNested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalReverseNested.java
index 1754a856b7a26..5852d8b1cd0dd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalReverseNested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/InternalReverseNested.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
@@ -40,6 +40,8 @@
 
 /**
  * Result of the {@link ReverseNestedAggregator}.
+ *
+ * @opensearch.internal
  */
 public class InternalReverseNested extends InternalSingleBucketAggregation implements ReverseNested {
     public InternalReverseNested(String name, long docCount, InternalAggregations aggregations, Map<String, Object> metadata) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/Nested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/Nested.java
index 9e3775bb095a9..e5d52e9e01e5b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/Nested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/Nested.java
@@ -35,5 +35,7 @@
 
 /**
  * A {@code nested} aggregation. Defines a single bucket that holds all the nested documents of a specific path.
+ *
+ * @opensearch.internal
  */
 public interface Nested extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregationBuilder.java
index 385ce67ffefa7..0d98fdbf15f78 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
@@ -49,6 +49,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for nested agg
+ *
+ * @opensearch.internal
+ */
 public class NestedAggregationBuilder extends AbstractAggregationBuilder<NestedAggregationBuilder> {
     public static final String NAME = "nested";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregator.java
index a003f1380253b..cfa1d32a52501 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregator.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import com.carrotsearch.hppc.LongArrayList;
 import org.apache.lucene.index.IndexReaderContext;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.ReaderUtil;
@@ -44,8 +43,8 @@
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.search.join.BitSetProducer;
 import org.apache.lucene.util.BitSet;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -58,8 +57,15 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs that match a nested path
+ *
+ * @opensearch.internal
+ */
 public class NestedAggregator extends BucketsAggregator implements SingleBucketAggregator {
 
     static final ParseField PATH_FIELD = new ParseField("path");
@@ -125,7 +131,8 @@ public void collect(int parentDoc, long bucket) throws IOException {
     }
 
     @Override
-    protected void preGetSubLeafCollectors() throws IOException {
+    protected void preGetSubLeafCollectors(LeafReaderContext ctx) throws IOException {
+        super.preGetSubLeafCollectors(ctx);
         processBufferedDocs();
     }
 
@@ -163,7 +170,7 @@ class BufferingNestedLeafBucketCollector extends LeafBucketCollectorBase {
         final BitSet parentDocs;
         final LeafBucketCollector sub;
         final DocIdSetIterator childDocs;
-        final LongArrayList bucketBuffer = new LongArrayList();
+        final List<Long> bucketBuffer = new ArrayList<>();
 
         Scorable scorer;
         int currentParentDoc = -1;
@@ -215,16 +222,19 @@ void processBufferedChildBuckets() throws IOException {
 
             for (; childDocId < currentParentDoc; childDocId = childDocs.nextDoc()) {
                 cachedScorer.doc = childDocId;
-                final long[] buffer = bucketBuffer.buffer;
-                final int size = bucketBuffer.size();
-                for (int i = 0; i < size; i++) {
-                    collectBucket(sub, childDocId, buffer[i]);
+                for (var bucket : bucketBuffer) {
+                    collectBucket(sub, childDocId, bucket);
                 }
             }
             bucketBuffer.clear();
         }
     }
 
+    /**
+     * A cached scorable doc
+     *
+     * @opensearch.internal
+     */
     private static class CachedScorable extends Scorable {
         int doc;
         float score;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorFactory.java
index 0102d1724351c..a43d41882e475 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorFactory.java
@@ -45,6 +45,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for nested agg
+ *
+ * @opensearch.internal
+ */
 public class NestedAggregatorFactory extends AggregatorFactory {
 
     private final ObjectMapper parentObjectMapper;
@@ -77,6 +82,11 @@ public Aggregator createInternal(
         return new NestedAggregator(name, factories, parentObjectMapper, childObjectMapper, searchContext, parent, cardinality, metadata);
     }
 
+    /**
+     * Unmapped class for nested agg
+     *
+     * @opensearch.internal
+     */
     private static final class Unmapped extends NonCollectingAggregator {
 
         Unmapped(String name, SearchContext context, Aggregator parent, AggregatorFactories factories, Map<String, Object> metadata)
@@ -90,4 +100,8 @@ public InternalAggregation buildEmptyAggregation() {
         }
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedNested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedNested.java
index 01e7593ecb95c..7ba1f6f2d97b5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedNested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedNested.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A nested agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedNested extends ParsedSingleBucketAggregation implements Nested {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedReverseNested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedReverseNested.java
index 66a789f4c35d2..2f79e742d18e3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedReverseNested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ParsedReverseNested.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A reverse nested agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedReverseNested extends ParsedSingleBucketAggregation implements ReverseNested {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNested.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNested.java
index 871c185d50210..1bc2383573e6c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNested.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNested.java
@@ -36,5 +36,7 @@
 
 /**
  * A {@code reverse nested} aggregation. Defines a single bucket that holds all the parent documents for a specific nested path.
+ *
+ * @opensearch.internal
  */
 public interface ReverseNested extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregationBuilder.java
index 72854b36f2167..e798ec9402cb9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.support.NestedScope;
@@ -50,6 +50,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for reverse_nested agg
+ *
+ * @opensearch.internal
+ */
 public class ReverseNestedAggregationBuilder extends AbstractAggregationBuilder<ReverseNestedAggregationBuilder> {
     public static final String NAME = "reverse_nested";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregator.java
index 689304215e9c7..2ba5bdc164247 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregator.java
@@ -31,14 +31,13 @@
 
 package org.opensearch.search.aggregations.bucket.nested;
 
-import com.carrotsearch.hppc.LongIntHashMap;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.join.BitSetProducer;
 import org.apache.lucene.util.BitSet;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -51,8 +50,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Aggregates documents that match a nested path.
+ *
+ * @opensearch.internal
+ */
 public class ReverseNestedAggregator extends BucketsAggregator implements SingleBucketAggregator {
 
     static final ParseField PATH_FIELD = new ParseField("path");
@@ -86,7 +91,7 @@ protected LeafBucketCollector getLeafCollector(LeafReaderContext ctx, final Leaf
         if (parentDocs == null) {
             return LeafBucketCollector.NO_OP_COLLECTOR;
         }
-        final LongIntHashMap bucketOrdToLastCollectedParentDoc = new LongIntHashMap(32);
+        final Map<Long, Integer> bucketOrdToLastCollectedParentDoc = new HashMap<>(32);
         return new LeafBucketCollectorBase(sub, null) {
             @Override
             public void collect(int childDoc, long bucket) throws IOException {
@@ -94,16 +99,15 @@ public void collect(int childDoc, long bucket) throws IOException {
                 final int parentDoc = parentDocs.nextSetBit(childDoc);
                 assert childDoc <= parentDoc && parentDoc != DocIdSetIterator.NO_MORE_DOCS;
 
-                int keySlot = bucketOrdToLastCollectedParentDoc.indexOf(bucket);
-                if (bucketOrdToLastCollectedParentDoc.indexExists(keySlot)) {
-                    int lastCollectedParentDoc = bucketOrdToLastCollectedParentDoc.indexGet(keySlot);
+                Integer lastCollectedParentDoc = bucketOrdToLastCollectedParentDoc.get(bucket);
+                if (lastCollectedParentDoc != null) {
                     if (parentDoc > lastCollectedParentDoc) {
                         collectBucket(sub, parentDoc, bucket);
-                        bucketOrdToLastCollectedParentDoc.indexReplace(keySlot, parentDoc);
+                        bucketOrdToLastCollectedParentDoc.put(bucket, parentDoc);
                     }
                 } else {
                     collectBucket(sub, parentDoc, bucket);
-                    bucketOrdToLastCollectedParentDoc.indexInsert(keySlot, bucket, parentDoc);
+                    bucketOrdToLastCollectedParentDoc.put(bucket, parentDoc);
                 }
             }
         };
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorFactory.java
index 202645c8638ab..816f05052b6a2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorFactory.java
@@ -45,6 +45,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for reverse_nested agg
+ *
+ * @opensearch.internal
+ */
 public class ReverseNestedAggregatorFactory extends AggregatorFactory {
 
     private final boolean unmapped;
@@ -78,6 +83,16 @@ public Aggregator createInternal(
         }
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
+    /**
+     * Unmapped class for reverse nested agg
+     *
+     * @opensearch.internal
+     */
     private static final class Unmapped extends NonCollectingAggregator {
 
         Unmapped(String name, SearchContext context, Aggregator parent, AggregatorFactories factories, Map<String, Object> metadata)
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/package-info.java
new file mode 100644
index 0000000000000..1eceaa248afb6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/nested/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Nested Aggregation package. */
+package org.opensearch.search.aggregations.bucket.nested;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info b/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info
deleted file mode 100644
index a2cb4a9493c56..0000000000000
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- * Aggregations module
- */
-package org.opensearch.search.aggregations.bucket;
-
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info.java
new file mode 100644
index 0000000000000..52b88548dacdd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Aggregations module
+ */
+package org.opensearch.search.aggregations.bucket;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeAggregatorFactory.java
index 973ef10881e68..41f2768eb7544 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeAggregatorFactory.java
@@ -47,8 +47,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Base Aggregation Factory for range aggs
+ *
+ * @opensearch.internal
+ */
 public class AbstractRangeAggregatorFactory<R extends Range> extends ValuesSourceAggregatorFactory {
 
     private final InternalRange.Factory<?, ?> rangeFactory;
@@ -62,7 +68,7 @@ public static void registerAggregators(
     ) {
         builder.register(
             registryKey,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             RangeAggregator::new,
             true
         );
@@ -116,4 +122,9 @@ protected Aggregator doCreateInternal(
                 metadata
             );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeBuilder.java
index 083d80bba4efe..df44f5130cc85 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/AbstractRangeBuilder.java
@@ -33,10 +33,10 @@
 package org.opensearch.search.aggregations.bucket.range;
 
 import org.apache.lucene.util.InPlaceMergeSorter;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.bucket.range.RangeAggregator.Range;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
@@ -49,6 +49,11 @@
 import java.util.Objects;
 import java.util.function.Function;
 
+/**
+ * Base Aggregation Builder for range aggs
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractRangeBuilder<AB extends AbstractRangeBuilder<AB, R>, R extends Range> extends ValuesSourceAggregationBuilder<
     AB> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregator.java
index c4b4728db5364..a48649af99be3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregator.java
@@ -55,9 +55,18 @@
 
 import static java.util.Collections.emptyList;
 
-/** A range aggregator for values that are stored in SORTED_SET doc values. */
+/**
+ * A range aggregator for values that are stored in SORTED_SET doc values.
+ *
+ * @opensearch.internal
+ */
 public final class BinaryRangeAggregator extends BucketsAggregator {
 
+    /**
+     * Range for the binary range agg
+     *
+     * @opensearch.internal
+     */
     public static class Range {
 
         final String key;
@@ -140,6 +149,11 @@ protected void doCollect(LeafBucketCollector sub, int doc, long bucket) throws I
         }
     }
 
+    /**
+     * Leaf collector for the sorted set range
+     *
+     * @opensearch.internal
+     */
     abstract static class SortedSetRangeLeafCollector extends LeafBucketCollectorBase {
 
         final long[] froms, tos, maxTos;
@@ -246,6 +260,11 @@ private int collect(int doc, long ord, long bucket, int lowBound) throws IOExcep
         protected abstract void doCollect(LeafBucketCollector sub, int doc, long bucket) throws IOException;
     }
 
+    /**
+     * Base class for a sorted binary range leaf collector
+     *
+     * @opensearch.internal
+     */
     abstract static class SortedBinaryRangeLeafCollector extends LeafBucketCollectorBase {
 
         final Range[] ranges;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorFactory.java
index d1cadb9b9ec99..fc4b4273df703 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for binary_range
+ *
+ * @opensearch.internal
+ */
 public class BinaryRangeAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -98,4 +103,8 @@ protected Aggregator doCreateInternal(
             .build(name, factories, config.getValuesSource(), config.format(), ranges, keyed, searchContext, parent, cardinality, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregationBuilder.java
index bf0d012be55bb..7668aa78b4bc0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregationBuilder.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -49,6 +49,11 @@
 import java.time.ZonedDateTime;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for date_range agg
+ *
+ * @opensearch.internal
+ */
 public class DateRangeAggregationBuilder extends AbstractRangeBuilder<DateRangeAggregationBuilder, RangeAggregator.Range> {
     public static final String NAME = "date_range";
     public static final ValuesSourceRegistry.RegistryKey<RangeAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorFactory.java
index c9d9eb39ff9ba..dcf6b84164991 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorFactory.java
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for date_range agg
+ *
+ * @opensearch.internal
+ */
 public class DateRangeAggregatorFactory extends AbstractRangeAggregatorFactory<RangeAggregator.Range> {
 
     public DateRangeAggregatorFactory(
@@ -67,4 +72,8 @@ public DateRangeAggregatorFactory(
         );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregationBuilder.java
index 8e332cfd4a63a..e681c714cffbe 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregationBuilder.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
@@ -65,6 +65,11 @@
 import static org.opensearch.search.aggregations.bucket.range.RangeAggregator.Range.KEY_FIELD;
 import static org.opensearch.search.aggregations.bucket.range.RangeAggregator.Range.TO_FIELD;
 
+/**
+ * Aggregation Builder for geo_distance agg
+ *
+ * @opensearch.internal
+ */
 public class GeoDistanceAggregationBuilder extends ValuesSourceAggregationBuilder<GeoDistanceAggregationBuilder> {
     public static final String NAME = "geo_distance";
     public static final ValuesSourceRegistry.RegistryKey<GeoDistanceAggregatorSupplier> REGISTRY_KEY =
@@ -116,6 +121,11 @@ public static AggregationBuilder parse(String aggregationName, XContentParser pa
         return builder;
     }
 
+    /**
+     * Range for a geo distance agg
+     *
+     * @opensearch.internal
+     */
     public static class Range extends RangeAggregator.Range {
         public Range(String key, Double from, Double to) {
             super(key(key, from, to), from == null ? 0 : from, to);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregatorSupplier.java
index 430cbf4176c55..c4a9efda18bda 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceAggregatorSupplier.java
@@ -44,6 +44,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for geo_distance agg
+ *
+ * @opensearch.internal
+ */
 public interface GeoDistanceAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceRangeAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceRangeAggregatorFactory.java
index ba054357b4af2..728f43094cf7e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceRangeAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/GeoDistanceRangeAggregatorFactory.java
@@ -57,6 +57,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for geo_distance agg
+ *
+ * @opensearch.internal
+ */
 public class GeoDistanceRangeAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -167,6 +172,16 @@ protected Aggregator doCreateInternal(
             );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
+    /**
+     * The source location for the distance calculation
+     *
+     * @opensearch.internal
+     */
     private static class DistanceSource extends ValuesSource.Numeric {
 
         private final ValuesSource.GeoPoint source;
@@ -193,6 +208,11 @@ public boolean isFloatingPoint() {
             return true;
         }
 
+        @Override
+        public boolean isBigInteger() {
+            return false;
+        }
+
         @Override
         public SortedNumericDocValues longValues(LeafReaderContext ctx) {
             throw new UnsupportedOperationException();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalBinaryRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalBinaryRange.java
index 506593113a0f8..b98747b89f450 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalBinaryRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalBinaryRange.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.bucket.range;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -52,11 +52,20 @@
 
 import static java.util.Collections.unmodifiableList;
 
-/** A range aggregation for data that is encoded in doc values using a binary representation. */
+/**
+ * A range aggregation for data that is encoded in doc values using a binary representation.
+ *
+ * @opensearch.internal
+ */
 public final class InternalBinaryRange extends InternalMultiBucketAggregation<InternalBinaryRange, InternalBinaryRange.Bucket>
     implements
         Range {
 
+    /**
+     * Bucket for a binary range agg
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Range.Bucket {
 
         private final transient DocValueFormat format;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalDateRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalDateRange.java
index 6becf1f692cb2..146aa728a88b7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalDateRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalDateRange.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -43,9 +43,19 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Implementation of date range bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalDateRange extends InternalRange<InternalDateRange.Bucket, InternalDateRange> {
     public static final Factory FACTORY = new Factory();
 
+    /**
+     * Bucket for a date range
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalRange.Bucket {
 
         public Bucket(
@@ -108,6 +118,11 @@ DocValueFormat format() {
         }
     }
 
+    /**
+     * Factory to create a date range
+     *
+     * @opensearch.internal
+     */
     public static class Factory extends InternalRange.Factory<InternalDateRange.Bucket, InternalDateRange> {
         @Override
         public ValueType getValueType() {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalGeoDistance.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalGeoDistance.java
index 6b3a19e1113e3..5d58a139b5023 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalGeoDistance.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalGeoDistance.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
@@ -42,9 +42,19 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Implementation of geo_distance bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalGeoDistance extends InternalRange<InternalGeoDistance.Bucket, InternalGeoDistance> {
     public static final Factory FACTORY = new Factory();
 
+    /**
+     * Bucket for a geo distance range
+     *
+     * @opensearch.internal
+     */
     static class Bucket extends InternalRange.Bucket {
 
         Bucket(String key, double from, double to, long docCount, InternalAggregations aggregations, boolean keyed) {
@@ -61,6 +71,11 @@ boolean keyed() {
         }
     }
 
+    /**
+     * Factory for a geo distance bucket
+     *
+     * @opensearch.internal
+     */
     public static class Factory extends InternalRange.Factory<InternalGeoDistance.Bucket, InternalGeoDistance> {
         @Override
         public ValuesSourceType getValueSourceType() {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalRange.java
index ff61a0fd87e58..2abe196416e52 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/InternalRange.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -49,11 +49,21 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of range bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalRange<B extends InternalRange.Bucket, R extends InternalRange<B, R>> extends InternalMultiBucketAggregation<R, B>
     implements
         Range {
     static final Factory FACTORY = new Factory();
 
+    /**
+     * Bucket for a range
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalMultiBucketAggregation.InternalBucket implements Range.Bucket {
 
         protected final transient boolean keyed;
@@ -206,6 +216,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * Factory for a range
+     *
+     * @opensearch.internal
+     */
     public static class Factory<B extends Bucket, R extends InternalRange<B, R>> {
         public ValuesSourceType getValueSourceType() {
             return CoreValuesSourceType.NUMERIC;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregationBuilder.java
index 1a691a074a5e2..1470712567775 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregationBuilder.java
@@ -33,17 +33,17 @@
 
 import org.apache.lucene.document.InetAddressPoint;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -65,6 +65,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for ip_range agg
+ *
+ * @opensearch.internal
+ */
 public final class IpRangeAggregationBuilder extends ValuesSourceAggregationBuilder<IpRangeAggregationBuilder> {
     public static final String NAME = "ip_range";
     public static final ValuesSourceRegistry.RegistryKey<IpRangeAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
@@ -123,6 +128,11 @@ private static Range parseRange(XContentParser parser) throws IOException {
         }
     }
 
+    /**
+     * Range for an IP range
+     *
+     * @opensearch.internal
+     */
     public static class Range implements ToXContentObject {
 
         private final String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorSupplier.java
index e3de71a9b3cda..5efe9d952911b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorSupplier.java
@@ -43,6 +43,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for ip_range agg
+ *
+ * @opensearch.internal
+ */
 public interface IpRangeAggregatorSupplier {
 
     Aggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedBinaryRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedBinaryRange.java
index 13f52759ea1a1..9b687022f5302 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedBinaryRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedBinaryRange.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -44,8 +44,13 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * A binary range agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedBinaryRange extends ParsedMultiBucketAggregation<ParsedBinaryRange.ParsedBucket> implements Range {
 
     @Override
@@ -77,6 +82,11 @@ public static ParsedBinaryRange fromXContent(XContentParser parser, String name)
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a binary range
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Range.Bucket {
 
         private String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedDateRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedDateRange.java
index a388fdd3d20be..4d777dfbcdba1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedDateRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedDateRange.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 
+/**
+ * A date range agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedDateRange extends ParsedRange {
 
     @Override
@@ -66,6 +71,11 @@ public static ParsedDateRange fromXContent(XContentParser parser, String name) t
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a date range
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedRange.ParsedBucket {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedGeoDistance.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedGeoDistance.java
index 1877a951f38b1..cddb37cfa8945 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedGeoDistance.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedGeoDistance.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A geo distance range agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedGeoDistance extends ParsedRange {
 
     @Override
@@ -63,6 +68,11 @@ public static ParsedGeoDistance fromXContent(XContentParser parser, String name)
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a geo distance
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedRange.ParsedBucket {
 
         static ParsedBucket fromXContent(final XContentParser parser, final boolean keyed) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedRange.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedRange.java
index ea7f4456bbdce..1922debd40271 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedRange.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/ParsedRange.java
@@ -33,10 +33,10 @@
 package org.opensearch.search.aggregations.bucket.range;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -46,8 +46,13 @@
 import java.util.List;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * A range agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedRange extends ParsedMultiBucketAggregation<ParsedRange.ParsedBucket> implements Range {
 
     @Override
@@ -87,6 +92,11 @@ public static ParsedRange fromXContent(XContentParser parser, String name) throw
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for a range
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Range.Bucket {
 
         protected String key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/Range.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/Range.java
index 55619acf233a3..0a979a9a1625b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/Range.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/Range.java
@@ -38,6 +38,8 @@
 /**
  * A {@code range} aggregation. Defines multiple buckets, each associated with a pre-defined value range of a field,
  * and where the value of that fields in all documents in each bucket fall in the bucket's range.
+ *
+ * @opensearch.internal
  */
 public interface Range extends MultiBucketsAggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilder.java
index c50bcc1b61493..c027587aacbd1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilder.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ObjectParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -47,6 +47,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for range agg
+ *
+ * @opensearch.internal
+ */
 public class RangeAggregationBuilder extends AbstractRangeBuilder<RangeAggregationBuilder, Range> {
     public static final String NAME = "range";
     public static final ValuesSourceRegistry.RegistryKey<RangeAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregator.java
index 9786bc63405b5..b56b817b8177b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregator.java
@@ -33,16 +33,16 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.ScoreMode;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
@@ -63,13 +63,23 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * Aggregate all docs that match given ranges.
+ *
+ * @opensearch.internal
+ */
 public class RangeAggregator extends BucketsAggregator {
 
     public static final ParseField RANGES_FIELD = new ParseField("ranges");
     public static final ParseField KEYED_FIELD = new ParseField("keyed");
 
+    /**
+     * Range for the range aggregator
+     *
+     * @opensearch.internal
+     */
     public static class Range implements Writeable, ToXContentObject {
         public static final ParseField KEY_FIELD = new ParseField("key");
         public static final ParseField FROM_FIELD = new ParseField("from");
@@ -378,6 +388,11 @@ public InternalAggregation buildEmptyAggregation() {
         return rangeFactory.create(name, buckets, format, keyed, metadata());
     }
 
+    /**
+     * Unmapped range
+     *
+     * @opensearch.internal
+     */
     public static class Unmapped<R extends RangeAggregator.Range> extends NonCollectingAggregator {
 
         private final R[] ranges;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorFactory.java
index b2a1b1046aaa2..c58b2e881803c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorFactory.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for range aggregators
+ *
+ * @opensearch.internal
+ */
 public class RangeAggregatorFactory extends AbstractRangeAggregatorFactory<RangeAggregator.Range> {
 
     public RangeAggregatorFactory(
@@ -68,4 +73,9 @@ public RangeAggregatorFactory(
             metadata
         );
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorSupplier.java
index ecc6c6cde442d..de9b979a56107 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorSupplier.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base Aggregator supplier interface for range aggs
+ *
+ * @opensearch.internal
+ */
 public interface RangeAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/range/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/package-info.java
new file mode 100644
index 0000000000000..5567c241abcae
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/range/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Range Aggregation package. */
+package org.opensearch.search.aggregations.bucket.range;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollector.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollector.java
index 42ef44e642d4e..080142185f82e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollector.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollector.java
@@ -64,6 +64,8 @@
  * {@link BestDocsDeferringCollector#createTopDocsCollector(int)} is designed to
  * be overridden and allows subclasses to choose a custom collector
  * implementation for determining the top N matches.
+ *
+ * @opensearch.internal
  */
 public class BestDocsDeferringCollector extends DeferringBucketCollector implements Releasable {
     private final List<PerSegmentCollects> entries = new ArrayList<>();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregationBuilder.java
index dc1ddddaa4721..c905d99507658 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.sampler;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for diversified_sampler agg
+ *
+ * @opensearch.internal
+ */
 public class DiversifiedAggregationBuilder extends ValuesSourceAggregationBuilder<DiversifiedAggregationBuilder> {
     public static final String NAME = "diversified_sampler";
     public static final ValuesSourceRegistry.RegistryKey<DiversifiedAggregatorSupplier> REGISTRY_KEY =
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorFactory.java
index f7b43a0da2337..5f81c76b69385 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorFactory.java
@@ -47,14 +47,20 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for diversified_sampler agg
+ *
+ * @opensearch.internal
+ */
 public class DiversifiedAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             DiversifiedAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             (
                 String name,
                 int shardSize,
@@ -153,4 +159,9 @@ public InternalAggregation buildEmptyAggregation() {
             }
         };
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorSupplier.java
index 9992a18aa13ea..8f8b4f970ee84 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedAggregatorSupplier.java
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base Aggregator supplier interface for diversified sampling aggs
+ *
+ * @opensearch.internal
+ */
 public interface DiversifiedAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedBytesHashSamplerAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedBytesHashSamplerAggregator.java
index c0b3536838430..555e45460b844 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedBytesHashSamplerAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedBytesHashSamplerAggregator.java
@@ -55,6 +55,8 @@
 /**
  * Alternative, faster implementation for converting String keys to longs but
  * with the potential for hash collisions.
+ *
+ * @opensearch.internal
  */
 public class DiversifiedBytesHashSamplerAggregator extends SamplerAggregator {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedMapSamplerAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedMapSamplerAggregator.java
index fdb00eed24c0d..cb880759887e4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedMapSamplerAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedMapSamplerAggregator.java
@@ -54,6 +54,11 @@
 import java.util.Map;
 import java.util.function.Consumer;
 
+/**
+ * Aggregate all docs that match the diversified map sample
+ *
+ * @opensearch.internal
+ */
 public class DiversifiedMapSamplerAggregator extends SamplerAggregator {
 
     private ValuesSource valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedNumericSamplerAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedNumericSamplerAggregator.java
index 8b4bed89e678c..472cc1beb82f8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedNumericSamplerAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedNumericSamplerAggregator.java
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.function.Consumer;
 
+/**
+ * Aggregate all docs that match the diversified numeric sample
+ *
+ * @opensearch.internal
+ */
 public class DiversifiedNumericSamplerAggregator extends SamplerAggregator {
 
     private ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedOrdinalsSamplerAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedOrdinalsSamplerAggregator.java
index 62caa017eddba..953a45971919c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedOrdinalsSamplerAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedOrdinalsSamplerAggregator.java
@@ -52,6 +52,11 @@
 import java.util.Map;
 import java.util.function.Consumer;
 
+/**
+ * Aggregate all docs that match the diversified ordinal sample
+ *
+ * @opensearch.internal
+ */
 public class DiversifiedOrdinalsSamplerAggregator extends SamplerAggregator {
 
     private ValuesSource.Bytes.WithOrdinals.FieldData valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/InternalSampler.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/InternalSampler.java
index 593c3c50ee19d..b05c501b55dc1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/InternalSampler.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/InternalSampler.java
@@ -31,13 +31,18 @@
 
 package org.opensearch.search.aggregations.bucket.sampler;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Implementation of sampler bucket
+ *
+ * @opensearch.internal
+ */
 public class InternalSampler extends InternalSingleBucketAggregation implements Sampler {
     public static final String NAME = "mapped_sampler";
     // InternalSampler and UnmappedSampler share the same parser name, so we use this when identifying the aggregation type
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/ParsedSampler.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/ParsedSampler.java
index 6c4fe2927d7bd..031658d0075f6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/ParsedSampler.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/ParsedSampler.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.aggregations.bucket.sampler;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
 
 import java.io.IOException;
 
+/**
+ * A sampler result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedSampler extends ParsedSingleBucketAggregation implements Sampler {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/Sampler.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/Sampler.java
index 45fbf6913fd04..a9c2a76a69b85 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/Sampler.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/Sampler.java
@@ -37,5 +37,7 @@
  * A {@code filter} aggregation that defines a single bucket to hold a sample of
  * top-matching documents. Computation of child aggregations is deferred until
  * the top-matching documents on a shard have been determined.
+ *
+ * @opensearch.internal
  */
 public interface Sampler extends SingleBucketAggregation {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregationBuilder.java
index 42aebe384f0f9..951329fa81fcc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.bucket.sampler;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -47,6 +47,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for sampler agg
+ *
+ * @opensearch.internal
+ */
 public class SamplerAggregationBuilder extends AbstractAggregationBuilder<SamplerAggregationBuilder> {
     public static final String NAME = "sampler";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregator.java
index a7855c2b400f1..23e2bc6b3e54b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregator.java
@@ -35,9 +35,9 @@
 import org.apache.lucene.misc.search.DiversifiedTopDocsCollector;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.util.RamUsageEstimator;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.core.ParseField;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -62,6 +62,8 @@
  * as the basis for generating de-dup values. Their syntax for creating bucket
  * values would be preferable to users having to recreate this logic in a
  * 'script' e.g. to turn a datetime in milliseconds into a month key value.
+ *
+ * @opensearch.internal
  */
 public class SamplerAggregator extends DeferableBucketAggregator implements SingleBucketAggregator {
 
@@ -71,6 +73,11 @@ public class SamplerAggregator extends DeferableBucketAggregator implements Sing
 
     static final long SCOREDOCKEY_SIZE = RamUsageEstimator.shallowSizeOfInstance(DiversifiedTopDocsCollector.ScoreDocKey.class);
 
+    /**
+     * The execution mode for the sampler
+     *
+     * @opensearch.internal
+     */
     public enum ExecutionMode {
 
         MAP(new ParseField("map")) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregatorFactory.java
index 35e3a618dfad3..d3db8a66ee21f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/SamplerAggregatorFactory.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for sampler agg
+ *
+ * @opensearch.internal
+ */
 public class SamplerAggregatorFactory extends AggregatorFactory {
 
     private final int shardSize;
@@ -68,4 +73,8 @@ public Aggregator createInternal(
         return new SamplerAggregator(name, shardSize, factories, searchContext, parent, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/UnmappedSampler.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/UnmappedSampler.java
index 620a6e02c2b9a..a22d20addb49d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/UnmappedSampler.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/UnmappedSampler.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.search.aggregations.bucket.sampler;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -41,6 +41,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Implementation of an unmapped sampler
+ *
+ * @opensearch.internal
+ */
 public class UnmappedSampler extends InternalSampler {
     public static final String NAME = "unmapped_sampler";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/package-info.java
new file mode 100644
index 0000000000000..8a4cc512da13a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/sampler/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Sampler Aggregation package. */
+package org.opensearch.search.aggregations.bucket.sampler;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractRareTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractRareTermsAggregator.java
index 5820652b179d2..6ca66b38408a0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractRareTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractRareTermsAggregator.java
@@ -47,6 +47,11 @@
 import java.util.Map;
 import java.util.Random;
 
+/**
+ * Base class to Aggregate all docs that contain rare terms
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractRareTermsAggregator extends DeferableBucketAggregator {
 
     static final BucketOrder ORDER = BucketOrder.compound(BucketOrder.count(true), BucketOrder.key(true)); // sort by count ascending
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractStringTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractStringTermsAggregator.java
index 9e83891067237..d06a0ed9976fc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractStringTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/AbstractStringTermsAggregator.java
@@ -46,6 +46,11 @@
 
 import static java.util.Collections.emptyList;
 
+/**
+ * Base Aggregator to collect all docs that contain significant terms
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractStringTermsAggregator extends TermsAggregator {
 
     protected final boolean showTermDocCountError;
@@ -71,15 +76,14 @@ protected StringTerms buildEmptyTermsAggregation() {
             name,
             order,
             order,
-            bucketCountThresholds.getRequiredSize(),
-            bucketCountThresholds.getMinDocCount(),
             metadata(),
             format,
             bucketCountThresholds.getShardSize(),
             showTermDocCountError,
             0,
             emptyList(),
-            0
+            0,
+            bucketCountThresholds
         );
     }
 
@@ -90,14 +94,13 @@ protected SignificantStringTerms buildEmptySignificantTermsAggregation(long subs
         int supersetSize = topReader.numDocs();
         return new SignificantStringTerms(
             name,
-            bucketCountThresholds.getRequiredSize(),
-            bucketCountThresholds.getMinDocCount(),
             metadata(),
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            emptyList()
+            emptyList(),
+            bucketCountThresholds
         );
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketPriorityQueue.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketPriorityQueue.java
index 258a6c43c49ab..29314c08cfab9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketPriorityQueue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketPriorityQueue.java
@@ -35,6 +35,11 @@
 
 import java.util.Comparator;
 
+/**
+ * Internal priority queue for computing terms aggs
+ *
+ * @opensearch.internal
+ */
 public class BucketPriorityQueue<B extends Terms.Bucket> extends PriorityQueue<B> {
 
     private final Comparator<? super B> comparator;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketSignificancePriorityQueue.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketSignificancePriorityQueue.java
index 7a112135567b9..25e016fb77c9f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketSignificancePriorityQueue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BucketSignificancePriorityQueue.java
@@ -34,6 +34,11 @@
 
 import org.apache.lucene.util.PriorityQueue;
 
+/**
+ * Priority queue for computing bucket significance
+ *
+ * @opensearch.internal
+ */
 public class BucketSignificancePriorityQueue<B extends SignificantTerms.Bucket> extends PriorityQueue<B> {
 
     public BucketSignificancePriorityQueue(int size) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrds.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrds.java
index 1cdf4f509537b..5d7c5c2976169 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrds.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrds.java
@@ -41,6 +41,8 @@
 
 /**
  * Maps {@link BytesRef} bucket keys to bucket ordinals.
+ *
+ * @opensearch.internal
  */
 public abstract class BytesKeyedBucketOrds implements Releasable {
     /**
@@ -80,6 +82,8 @@ private BytesKeyedBucketOrds() {}
 
     /**
      * An iterator for buckets inside a particular {@code owningBucketOrd}.
+     *
+     * @opensearch.internal
      */
     public interface BucketOrdsEnum {
         /**
@@ -120,12 +124,14 @@ public void readValue(BytesRef dest) {}
 
     /**
      * Implementation that only works if it is collecting from a single bucket.
+     *
+     * @opensearch.internal
      */
     private static class FromSingle extends BytesKeyedBucketOrds {
         private final BytesRefHash ords;
 
         private FromSingle(BigArrays bigArrays) {
-            ords = new BytesRefHash(1, bigArrays);
+            ords = new BytesRefHash(bigArrays);
         }
 
         @Override
@@ -175,6 +181,8 @@ public void close() {
 
     /**
      * Implementation that works properly when collecting from many buckets.
+     *
+     * @opensearch.internal
      */
     private static class FromMany extends BytesKeyedBucketOrds {
         // TODO we can almost certainly do better here by building something fit for purpose rather than trying to lego together stuff
@@ -182,7 +190,7 @@ private static class FromMany extends BytesKeyedBucketOrds {
         private final LongKeyedBucketOrds longToBucketOrds;
 
         private FromMany(BigArrays bigArrays) {
-            bytesToLong = new BytesRefHash(1, bigArrays);
+            bytesToLong = new BytesRefHash(bigArrays);
             longToBucketOrds = LongKeyedBucketOrds.build(bigArrays, CardinalityUpperBound.MANY);
         }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/DoubleTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/DoubleTerms.java
index c556dd1144b24..de02d5a938644 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/DoubleTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/DoubleTerms.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -47,10 +47,17 @@
 
 /**
  * Result of the {@link TermsAggregator} when the field is some kind of decimal number like a float, double, or distance.
+ *
+ * @opensearch.internal
  */
 public class DoubleTerms extends InternalMappedTerms<DoubleTerms, DoubleTerms.Bucket> {
     public static final String NAME = "dterms";
 
+    /**
+     * Bucket for a double terms agg
+     *
+     * @opensearch.internal
+     */
     static class Bucket extends InternalTerms.Bucket<Bucket> {
         double term;
 
@@ -123,29 +130,27 @@ public DoubleTerms(
         String name,
         BucketOrder reduceOrder,
         BucketOrder order,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         int shardSize,
         boolean showTermDocCountError,
         long otherDocCount,
         List<Bucket> buckets,
-        long docCountError
+        long docCountError,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
         super(
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -167,15 +172,14 @@ public DoubleTerms create(List<Bucket> buckets) {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -197,15 +201,14 @@ protected DoubleTerms create(String name, List<Bucket> buckets, BucketOrder redu
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             getMetadata(),
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -226,7 +229,17 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
                  */
                 promoteToDouble = true;
                 break;
-            }
+            } else if (agg instanceof UnsignedLongTerms
+                && (((UnsignedLongTerms) agg).format == DocValueFormat.RAW
+                    || ((UnsignedLongTerms) agg).format == DocValueFormat.UNSIGNED_LONG_SHIFTED
+                    || ((UnsignedLongTerms) agg).format == DocValueFormat.UNSIGNED_LONG)) {
+                        /*
+                         * this terms agg mixes unsigned longs and doubles, we must promote unsigned longs to doubles to make the internal aggs
+                         * compatible
+                         */
+                        promoteToDouble = true;
+                        break;
+                    }
         }
         if (promoteToDouble == false) {
             return super.reduce(aggregations, reduceContext);
@@ -236,6 +249,9 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
             if (agg instanceof LongTerms) {
                 DoubleTerms dTerms = LongTerms.convertLongTermsToDouble((LongTerms) agg, format);
                 newAggs.add(dTerms);
+            } else if (agg instanceof UnsignedLongTerms) {
+                DoubleTerms dTerms = UnsignedLongTerms.convertUnsignedLongTermsToDouble((UnsignedLongTerms) agg, format);
+                newAggs.add(dTerms);
             } else {
                 newAggs.add(agg);
             }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java
index 40b43d11c5b3b..5ed899408ab40 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java
@@ -40,13 +40,12 @@
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
-import org.opensearch.common.util.IntArray;
 import org.opensearch.common.util.LongArray;
 import org.opensearch.common.util.LongHash;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregator;
@@ -58,6 +57,7 @@
 import org.opensearch.search.aggregations.InternalOrder;
 import org.opensearch.search.aggregations.LeafBucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollectorBase;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
 import org.opensearch.search.aggregations.bucket.terms.SignificanceLookup.BackgroundFrequencyForBytes;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 import org.opensearch.search.aggregations.support.ValuesSource;
@@ -71,11 +71,13 @@
 import java.util.function.LongPredicate;
 import java.util.function.LongUnaryOperator;
 
-import static org.apache.lucene.index.SortedSetDocValues.NO_MORE_ORDS;
 import static org.opensearch.search.aggregations.InternalOrder.isKeyOrder;
+import static org.apache.lucene.index.SortedSetDocValues.NO_MORE_ORDS;
 
 /**
  * An aggregator of string values that relies on global ordinals in order to build buckets.
+ *
+ * @opensearch.internal
  */
 public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggregator {
     protected final ResultStrategy<?, ?, ?> resultStrategy;
@@ -88,6 +90,11 @@ public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggr
     protected int segmentsWithSingleValuedOrds = 0;
     protected int segmentsWithMultiValuedOrds = 0;
 
+    /**
+     * Lookup global ordinals
+     *
+     * @opensearch.internal
+     */
     public interface GlobalOrdLookupFunction {
         BytesRef apply(long ord) throws IOException;
     }
@@ -229,6 +236,8 @@ public void collectDebugInfo(BiConsumer<String, Object> add) {
 
     /**
      * This is used internally only, just for compare using global ordinal instead of term bytes in the PQ
+     *
+     * @opensearch.internal
      */
     static class OrdBucket extends InternalTerms.Bucket<OrdBucket> {
         long globalOrd;
@@ -282,11 +291,13 @@ protected void doClose() {
      * This is only supported for the standard {@code terms} aggregation and
      * doesn't support {@code significant_terms} so this forces
      * {@link StandardTermsResults}.
+     *
+     * @opensearch.internal
      */
     static class LowCardinality extends GlobalOrdinalsStringTermsAggregator {
 
         private LongUnaryOperator mapping;
-        private IntArray segmentDocCounts;
+        private LongArray segmentDocCounts;
 
         LowCardinality(
             String name,
@@ -321,7 +332,7 @@ static class LowCardinality extends GlobalOrdinalsStringTermsAggregator {
                 metadata
             );
             assert factories == null || factories.countAggregators() == 0;
-            this.segmentDocCounts = context.bigArrays().newIntArray(1, true);
+            this.segmentDocCounts = context.bigArrays().newLongArray(1, true);
         }
 
         @Override
@@ -345,7 +356,8 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
                             return;
                         }
                         int ord = singleValues.ordValue();
-                        segmentDocCounts.increment(ord + 1, 1);
+                        long docCount = docCountProvider.getDocCount(doc);
+                        segmentDocCounts.increment(ord + 1, docCount);
                     }
                 });
             }
@@ -358,7 +370,8 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
                         return;
                     }
                     for (long segmentOrd = segmentOrds.nextOrd(); segmentOrd != NO_MORE_ORDS; segmentOrd = segmentOrds.nextOrd()) {
-                        segmentDocCounts.increment(segmentOrd + 1, 1);
+                        long docCount = docCountProvider.getDocCount(doc);
+                        segmentDocCounts.increment(segmentOrd + 1, docCount);
                     }
                 }
             });
@@ -381,7 +394,7 @@ private void mapSegmentCountsToGlobalCounts(LongUnaryOperator mapping) throws IO
             for (long i = 1; i < segmentDocCounts.size(); i++) {
                 // We use set(...) here, because we need to reset the slow to 0.
                 // segmentDocCounts get reused over the segments and otherwise counts would be too high.
-                int inc = segmentDocCounts.set(i, 0);
+                long inc = segmentDocCounts.set(i, 0);
                 if (inc == 0) {
                     continue;
                 }
@@ -591,6 +604,7 @@ abstract class ResultStrategy<
         TB extends InternalMultiBucketAggregation.InternalBucket> implements Releasable {
 
         private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
+            LocalBucketCountThresholds localBucketCountThresholds = context.asLocalBucketCountThresholds(bucketCountThresholds);
             if (valueCount == 0) { // no context in this reader
                 InternalAggregation[] results = new InternalAggregation[owningBucketOrds.length];
                 for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
@@ -603,11 +617,11 @@ private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws
             long[] otherDocCount = new long[owningBucketOrds.length];
             for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
                 final int size;
-                if (bucketCountThresholds.getMinDocCount() == 0) {
+                if (localBucketCountThresholds.getMinDocCount() == 0) {
                     // if minDocCount == 0 then we can end up with more buckets then maxBucketOrd() returns
-                    size = (int) Math.min(valueCount, bucketCountThresholds.getShardSize());
+                    size = (int) Math.min(valueCount, localBucketCountThresholds.getRequiredSize());
                 } else {
-                    size = (int) Math.min(maxBucketOrd(), bucketCountThresholds.getShardSize());
+                    size = (int) Math.min(maxBucketOrd(), localBucketCountThresholds.getRequiredSize());
                 }
                 PriorityQueue<TB> ordered = buildPriorityQueue(size);
                 final int finalOrdIdx = ordIdx;
@@ -618,7 +632,7 @@ private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws
                     @Override
                     public void accept(long globalOrd, long bucketOrd, long docCount) throws IOException {
                         otherDocCount[finalOrdIdx] += docCount;
-                        if (docCount >= bucketCountThresholds.getShardMinDocCount()) {
+                        if (docCount >= localBucketCountThresholds.getMinDocCount()) {
                             if (spare == null) {
                                 spare = buildEmptyTemporaryBucket();
                             }
@@ -787,15 +801,14 @@ StringTerms buildResult(long owningBucketOrd, long otherDocCount, StringTerms.Bu
                 name,
                 reduceOrder,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 otherDocCount,
                 Arrays.asList(topBuckets),
-                0
+                0,
+                bucketCountThresholds
             );
         }
 
@@ -912,14 +925,13 @@ void buildSubAggs(SignificantStringTerms.Bucket[][] topBucketsPreOrd) throws IOE
         SignificantStringTerms buildResult(long owningBucketOrd, long otherDocCount, SignificantStringTerms.Bucket[] topBuckets) {
             return new SignificantStringTerms(
                 name,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 subsetSize(owningBucketOrd),
                 supersetSize,
                 significanceHeuristic,
-                Arrays.asList(topBuckets)
+                Arrays.asList(topBuckets),
+                bucketCountThresholds
             );
         }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/IncludeExclude.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/IncludeExclude.java
index e632a13b95fb7..f8061bcaca50f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/IncludeExclude.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/IncludeExclude.java
@@ -31,9 +31,6 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import com.carrotsearch.hppc.BitMixer;
-import com.carrotsearch.hppc.LongHashSet;
-import com.carrotsearch.hppc.LongSet;
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
@@ -48,13 +45,15 @@
 import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.common.util.BitMixer;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.IndexSettings;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
@@ -67,6 +66,8 @@
 /**
  * Defines the include/exclude regular expression filtering for string terms aggregation. In this filtering logic,
  * exclusion has precedence, where the {@code include} is evaluated first and then the {@code exclude}.
+ *
+ * @opensearch.internal
  */
 public class IncludeExclude implements Writeable, ToXContentFragment {
     public static final ParseField INCLUDE_FIELD = new ParseField("include");
@@ -78,6 +79,14 @@ public class IncludeExclude implements Writeable, ToXContentFragment {
     // can disagree on which terms hash to the required partition.
     private static final int HASH_PARTITIONING_SEED = 31;
 
+    /**
+     * The default length limit for a reg-ex string. The value is derived from {@link IndexSettings#MAX_REGEX_LENGTH_SETTING}.
+     * For context, see:
+     * https://github.com/opensearch-project/OpenSearch/issues/1992
+     * https://github.com/opensearch-project/OpenSearch/issues/2858
+     */
+    private static final int DEFAULT_MAX_REGEX_LENGTH = 1000;
+
     // for parsing purposes only
     // TODO: move all aggs to the same package so that this stuff could be pkg-private
     public static IncludeExclude merge(IncludeExclude include, IncludeExclude exclude) {
@@ -151,16 +160,29 @@ public static IncludeExclude parseExclude(XContentParser parser) throws IOExcept
         }
     }
 
+    /**
+     * Base filter class
+     *
+     * @opensearch.internal
+     */
     public abstract static class Filter {}
 
-    // The includeValue and excludeValue ByteRefs which are the result of the parsing
-    // process are converted into a LongFilter when used on numeric fields
-    // in the index.
+    /**
+     * The includeValue and excludeValue ByteRefs which are the result of the parsing
+     * process are converted into a LongFilter when used on numeric fields
+     * in the index.
+     *
+     * @opensearch.internal
+     */
     public abstract static class LongFilter extends Filter {
         public abstract boolean accept(long value);
-
     }
 
+    /**
+     * Long filter that is partitioned
+     *
+     * @opensearch.internal
+     */
     public class PartitionedLongFilter extends LongFilter {
         @Override
         public boolean accept(long value) {
@@ -170,16 +192,21 @@ public boolean accept(long value) {
         }
     }
 
+    /**
+     * Long filter backed by valid values
+     *
+     * @opensearch.internal
+     */
     public static class SetBackedLongFilter extends LongFilter {
-        private LongSet valids;
-        private LongSet invalids;
+        private Set<Long> valids;
+        private Set<Long> invalids;
 
         private SetBackedLongFilter(int numValids, int numInvalids) {
             if (numValids > 0) {
-                valids = new LongHashSet(numValids);
+                valids = new HashSet<>(numValids);
             }
             if (numInvalids > 0) {
-                invalids = new LongHashSet(numInvalids);
+                invalids = new HashSet<>(numInvalids);
             }
         }
 
@@ -197,7 +224,11 @@ private void addReject(long val) {
         }
     }
 
-    // Only used for the 'map' execution mode (ie. scripts)
+    /**
+     * Only used for the 'map' execution mode (ie. scripts)
+     *
+     * @opensearch.internal
+     */
     public abstract static class StringFilter extends Filter {
         public abstract boolean accept(BytesRef value);
     }
@@ -209,6 +240,11 @@ public boolean accept(BytesRef value) {
         }
     }
 
+    /**
+     * String filter backed by an automaton
+     *
+     * @opensearch.internal
+     */
     static class AutomatonBackedStringFilter extends StringFilter {
 
         private final ByteRunAutomaton runAutomaton;
@@ -226,6 +262,11 @@ public boolean accept(BytesRef value) {
         }
     }
 
+    /**
+     * String filter backed by a term list
+     *
+     * @opensearch.internal
+     */
     static class TermListBackedStringFilter extends StringFilter {
 
         private final Set<BytesRef> valids;
@@ -246,6 +287,11 @@ public boolean accept(BytesRef value) {
         }
     }
 
+    /**
+     * An ordinals filter
+     *
+     * @opensearch.internal
+     */
     public abstract static class OrdinalsFilter extends Filter {
         public abstract LongBitSet acceptedGlobalOrdinals(SortedSetDocValues globalOrdinals) throws IOException;
 
@@ -273,6 +319,11 @@ public LongBitSet acceptedGlobalOrdinals(SortedSetDocValues globalOrdinals) thro
         }
     }
 
+    /**
+     * An ordinals filter backed by an automaton
+     *
+     * @opensearch.internal
+     */
     static class AutomatonBackedOrdinalsFilter extends OrdinalsFilter {
 
         private final CompiledAutomaton compiled;
@@ -300,6 +351,11 @@ public LongBitSet acceptedGlobalOrdinals(SortedSetDocValues globalOrdinals) thro
 
     }
 
+    /**
+     * An ordinals filter backed by a terms list
+     *
+     * @opensearch.internal
+     */
     static class TermListBackedOrdinalsFilter extends OrdinalsFilter {
 
         private final SortedSet<BytesRef> includeValues;
@@ -337,19 +393,16 @@ public LongBitSet acceptedGlobalOrdinals(SortedSetDocValues globalOrdinals) thro
 
     }
 
-    private final RegExp include, exclude;
+    private final String include, exclude;
     private final SortedSet<BytesRef> includeValues, excludeValues;
     private final int incZeroBasedPartition;
     private final int incNumPartitions;
 
     /**
-     * @param include   The regular expression pattern for the terms to be included
-     * @param exclude   The regular expression pattern for the terms to be excluded
+     * @param include   The string or regular expression pattern for the terms to be included
+     * @param exclude   The string or regular expression pattern for the terms to be excluded
      */
-    public IncludeExclude(RegExp include, RegExp exclude) {
-        if (include == null && exclude == null) {
-            throw new IllegalArgumentException();
-        }
+    public IncludeExclude(String include, String exclude) {
         this.include = include;
         this.exclude = exclude;
         this.includeValues = null;
@@ -358,10 +411,6 @@ public IncludeExclude(RegExp include, RegExp exclude) {
         this.incNumPartitions = 0;
     }
 
-    public IncludeExclude(String include, String exclude) {
-        this(include == null ? null : new RegExp(include), exclude == null ? null : new RegExp(exclude));
-    }
-
     /**
      * @param includeValues   The terms to be included
      * @param excludeValues   The terms to be excluded
@@ -412,10 +461,8 @@ public IncludeExclude(StreamInput in) throws IOException {
             excludeValues = null;
             incZeroBasedPartition = 0;
             incNumPartitions = 0;
-            String includeString = in.readOptionalString();
-            include = includeString == null ? null : new RegExp(includeString);
-            String excludeString = in.readOptionalString();
-            exclude = excludeString == null ? null : new RegExp(excludeString);
+            include = in.readOptionalString();
+            exclude = in.readOptionalString();
             return;
         }
         include = null;
@@ -447,8 +494,8 @@ public void writeTo(StreamOutput out) throws IOException {
         boolean regexBased = isRegexBased();
         out.writeBoolean(regexBased);
         if (regexBased) {
-            out.writeOptionalString(include == null ? null : include.getOriginalString());
-            out.writeOptionalString(exclude == null ? null : exclude.getOriginalString());
+            out.writeOptionalString(include);
+            out.writeOptionalString(exclude);
         } else {
             boolean hasIncludes = includeValues != null;
             out.writeBoolean(hasIncludes);
@@ -506,6 +553,8 @@ private static SortedSet<BytesRef> convertToBytesRefSet(long[] values) {
 
     /**
      * Terms adapter around doc values.
+     *
+     * @opensearch.internal
      */
     private static class DocValuesTerms extends Terms {
 
@@ -584,26 +633,53 @@ public boolean isPartitionBased() {
         return incNumPartitions > 0;
     }
 
-    private Automaton toAutomaton() {
-        Automaton a = null;
+    private Automaton toAutomaton(int maxRegExLength) {
+        Automaton a;
         if (include != null) {
-            a = include.toAutomaton();
+            validateRegExpStringLength(include, maxRegExLength);
+            a = new RegExp(include).toAutomaton();
         } else if (includeValues != null) {
             a = Automata.makeStringUnion(includeValues);
         } else {
             a = Automata.makeAnyString();
         }
         if (exclude != null) {
-            a = Operations.minus(a, exclude.toAutomaton(), Operations.DEFAULT_DETERMINIZE_WORK_LIMIT);
+            validateRegExpStringLength(exclude, maxRegExLength);
+            Automaton excludeAutomaton = new RegExp(exclude).toAutomaton();
+            a = Operations.minus(a, excludeAutomaton, Operations.DEFAULT_DETERMINIZE_WORK_LIMIT);
         } else if (excludeValues != null) {
             a = Operations.minus(a, Automata.makeStringUnion(excludeValues), Operations.DEFAULT_DETERMINIZE_WORK_LIMIT);
         }
         return a;
     }
 
+    private static void validateRegExpStringLength(String source, int maxRegexLength) {
+        if (maxRegexLength > 0 && source.length() > maxRegexLength) {
+            throw new IllegalArgumentException(
+                "The length of regex ["
+                    + source.length()
+                    + "] used in the request has exceeded "
+                    + "the allowed maximum of ["
+                    + maxRegexLength
+                    + "]. "
+                    + "This maximum can be set by changing the ["
+                    + IndexSettings.MAX_REGEX_LENGTH_SETTING.getKey()
+                    + "] index level setting."
+            );
+        }
+    }
+
+    /**
+     * Wrapper method that imposes a default regex limit.
+     * See https://github.com/opensearch-project/OpenSearch/issues/2858
+     */
     public StringFilter convertToStringFilter(DocValueFormat format) {
+        return convertToStringFilter(format, DEFAULT_MAX_REGEX_LENGTH);
+    }
+
+    public StringFilter convertToStringFilter(DocValueFormat format, int maxRegexLength) {
         if (isRegexBased()) {
-            return new AutomatonBackedStringFilter(toAutomaton());
+            return new AutomatonBackedStringFilter(toAutomaton(maxRegexLength));
         }
         if (isPartitionBased()) {
             return new PartitionedStringFilter();
@@ -624,10 +700,18 @@ private static SortedSet<BytesRef> parseForDocValues(SortedSet<BytesRef> endUser
         return result;
     }
 
+    /**
+     * Wrapper method that imposes a default regex limit.
+     * See https://github.com/opensearch-project/OpenSearch/issues/2858
+     */
     public OrdinalsFilter convertToOrdinalsFilter(DocValueFormat format) {
+        return convertToOrdinalsFilter(format, DEFAULT_MAX_REGEX_LENGTH);
+    }
+
+    public OrdinalsFilter convertToOrdinalsFilter(DocValueFormat format, int maxRegexLength) {
 
         if (isRegexBased()) {
-            return new AutomatonBackedOrdinalsFilter(toAutomaton());
+            return new AutomatonBackedOrdinalsFilter(toAutomaton(maxRegexLength));
         }
         if (isPartitionBased()) {
             return new PartitionedOrdinalsFilter();
@@ -684,7 +768,7 @@ public LongFilter convertToDoubleFilter() {
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (include != null) {
-            builder.field(INCLUDE_FIELD.getPreferredName(), include.getOriginalString());
+            builder.field(INCLUDE_FIELD.getPreferredName(), include);
         } else if (includeValues != null) {
             builder.startArray(INCLUDE_FIELD.getPreferredName());
             for (BytesRef value : includeValues) {
@@ -698,7 +782,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.endObject();
         }
         if (exclude != null) {
-            builder.field(EXCLUDE_FIELD.getPreferredName(), exclude.getOriginalString());
+            builder.field(EXCLUDE_FIELD.getPreferredName(), exclude);
         } else if (excludeValues != null) {
             builder.startArray(EXCLUDE_FIELD.getPreferredName());
             for (BytesRef value : excludeValues) {
@@ -711,14 +795,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public int hashCode() {
-        return Objects.hash(
-            include == null ? null : include.getOriginalString(),
-            exclude == null ? null : exclude.getOriginalString(),
-            includeValues,
-            excludeValues,
-            incZeroBasedPartition,
-            incNumPartitions
-        );
+        return Objects.hash(include, exclude, includeValues, excludeValues, incZeroBasedPartition, incNumPartitions);
     }
 
     @Override
@@ -730,14 +807,8 @@ public boolean equals(Object obj) {
             return false;
         }
         IncludeExclude other = (IncludeExclude) obj;
-        return Objects.equals(
-            include == null ? null : include.getOriginalString(),
-            other.include == null ? null : other.include.getOriginalString()
-        )
-            && Objects.equals(
-                exclude == null ? null : exclude.getOriginalString(),
-                other.exclude == null ? null : other.exclude.getOriginalString()
-            )
+        return Objects.equals(include, other.include)
+            && Objects.equals(exclude, other.exclude)
             && Objects.equals(includeValues, other.includeValues)
             && Objects.equals(excludeValues, other.excludeValues)
             && Objects.equals(incZeroBasedPartition, other.incZeroBasedPartition)
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedRareTerms.java
index 7086fb4cba7d3..eb4b84b7eb301 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedRareTerms.java
@@ -35,10 +35,10 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.SetBackedScalingCuckooFilter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -53,6 +53,11 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * Implementation of mapped rare terms
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalMappedRareTerms<A extends InternalRareTerms<A, B>, B extends InternalRareTerms.Bucket<B>> extends
     InternalRareTerms<A, B> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedSignificantTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedSignificantTerms.java
index ab47a220a6524..a7c5427fa38cc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedSignificantTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedSignificantTerms.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 
@@ -46,6 +46,11 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * Implementation of mapped significant terms
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalMappedSignificantTerms<
     A extends InternalMappedSignificantTerms<A, B>,
     B extends InternalSignificantTerms.Bucket<B>> extends InternalSignificantTerms<A, B> {
@@ -59,16 +64,15 @@ public abstract class InternalMappedSignificantTerms<
 
     protected InternalMappedSignificantTerms(
         String name,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         long subsetSize,
         long supersetSize,
         SignificanceHeuristic significanceHeuristic,
-        List<B> buckets
+        List<B> buckets,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
-        super(name, requiredSize, minDocCount, metadata);
+        super(name, bucketCountThresholds, metadata);
         this.format = format;
         this.buckets = buckets;
         this.subsetSize = subsetSize;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedTerms.java
index 5070b6e8fefec..d542064df24d7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMappedTerms.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 
@@ -47,6 +47,8 @@
 
 /**
  * Common superclass for results of the terms aggregation on mapped fields.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalMappedTerms<A extends InternalTerms<A, B>, B extends InternalTerms.Bucket<B>> extends InternalTerms<A, B> {
     protected final DocValueFormat format;
@@ -62,17 +64,16 @@ protected InternalMappedTerms(
         String name,
         BucketOrder reduceOrder,
         BucketOrder order,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         int shardSize,
         boolean showTermDocCountError,
         long otherDocCount,
         List<B> buckets,
-        long docCountError
+        long docCountError,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
-        super(name, reduceOrder, order, requiredSize, minDocCount, metadata);
+        super(name, reduceOrder, order, bucketCountThresholds, metadata);
         this.format = format;
         this.shardSize = shardSize;
         this.showTermDocCountError = showTermDocCountError;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTerms.java
new file mode 100644
index 0000000000000..4d1cbd4ce72f1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTerms.java
@@ -0,0 +1,443 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.AggregationExecutionException;
+import org.opensearch.search.aggregations.Aggregations;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.aggregations.KeyComparable;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * Result of the {@link MultiTermsAggregator}.
+ *
+ * @opensearch.internal
+ */
+public class InternalMultiTerms extends InternalTerms<InternalMultiTerms, InternalMultiTerms.Bucket> {
+    /**
+     * Internal Multi Terms Bucket.
+     *
+     * @opensearch.internal
+     */
+    public static class Bucket extends InternalTerms.AbstractInternalBucket implements KeyComparable<Bucket> {
+
+        protected long bucketOrd;
+        /**
+         * list of terms values.
+         */
+        protected List<Object> termValues;
+        protected long docCount;
+        protected InternalAggregations aggregations;
+        protected boolean showDocCountError;
+        protected long docCountError;
+        /**
+         * A list of term's {@link DocValueFormat}.
+         */
+        protected final List<DocValueFormat> termFormats;
+
+        private static final String PIPE = "|";
+
+        /**
+         * Create default {@link Bucket}.
+         */
+        public static Bucket EMPTY(boolean showTermDocCountError, List<DocValueFormat> formats) {
+            return new Bucket(null, 0, null, showTermDocCountError, 0, formats);
+        }
+
+        public Bucket(
+            List<Object> values,
+            long docCount,
+            InternalAggregations aggregations,
+            boolean showDocCountError,
+            long docCountError,
+            List<DocValueFormat> formats
+        ) {
+            this.termValues = values;
+            this.docCount = docCount;
+            this.aggregations = aggregations;
+            this.showDocCountError = showDocCountError;
+            this.docCountError = docCountError;
+            this.termFormats = formats;
+        }
+
+        public Bucket(StreamInput in, List<DocValueFormat> formats, boolean showDocCountError) throws IOException {
+            this.termValues = in.readList(StreamInput::readGenericValue);
+            this.docCount = in.readVLong();
+            this.aggregations = InternalAggregations.readFrom(in);
+            this.showDocCountError = showDocCountError;
+            this.docCountError = -1;
+            if (showDocCountError) {
+                this.docCountError = in.readLong();
+            }
+            this.termFormats = formats;
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            builder.field(CommonFields.KEY.getPreferredName(), getKey());
+            builder.field(CommonFields.KEY_AS_STRING.getPreferredName(), getKeyAsString());
+            builder.field(CommonFields.DOC_COUNT.getPreferredName(), getDocCount());
+            if (showDocCountError) {
+                builder.field(DOC_COUNT_ERROR_UPPER_BOUND_FIELD_NAME.getPreferredName(), getDocCountError());
+            }
+            aggregations.toXContentInternal(builder, params);
+            builder.endObject();
+            return builder;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeCollection(termValues, StreamOutput::writeGenericValue);
+            out.writeVLong(docCount);
+            aggregations.writeTo(out);
+            if (showDocCountError) {
+                out.writeLong(docCountError);
+            }
+        }
+
+        @Override
+        public List<Object> getKey() {
+            List<Object> keys = new ArrayList<>(termValues.size());
+            for (int i = 0; i < termValues.size(); i++) {
+                keys.add(formatObject(termValues.get(i), termFormats.get(i)));
+            }
+            return keys;
+        }
+
+        @Override
+        public String getKeyAsString() {
+            return getKey().stream().map(Object::toString).collect(Collectors.joining(PIPE));
+        }
+
+        @Override
+        public long getDocCount() {
+            return docCount;
+        }
+
+        @Override
+        public Aggregations getAggregations() {
+            return aggregations;
+        }
+
+        @Override
+        void setDocCountError(long docCountError) {
+            this.docCountError = docCountError;
+        }
+
+        @Override
+        public void setDocCountError(Function<Long, Long> updater) {
+            this.docCountError = updater.apply(this.docCountError);
+        }
+
+        @Override
+        public boolean showDocCountError() {
+            return showDocCountError;
+        }
+
+        @Override
+        public Number getKeyAsNumber() {
+            throw new IllegalArgumentException("getKeyAsNumber is not supported by [" + MultiTermsAggregationBuilder.NAME + "]");
+        }
+
+        @Override
+        public long getDocCountError() {
+            if (!showDocCountError) {
+                throw new IllegalStateException("show_terms_doc_count_error is false");
+            }
+            return docCountError;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null || getClass() != obj.getClass()) {
+                return false;
+            }
+            Bucket other = (Bucket) obj;
+            if (showDocCountError && docCountError != other.docCountError) {
+                return false;
+            }
+            return termValues.equals(other.termValues)
+                && docCount == other.docCount
+                && aggregations.equals(other.aggregations)
+                && showDocCountError == other.showDocCountError;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(termValues, docCount, aggregations, showDocCountError, showDocCountError ? docCountError : 0);
+        }
+
+        @Override
+        public int compareKey(Bucket other) {
+            return new BucketComparator().compare(this.termValues, other.termValues);
+        }
+
+        /**
+         * Visible for testing.
+         *
+         * @opensearch.internal
+         */
+        protected static class BucketComparator implements Comparator<List<Object>> {
+            @SuppressWarnings({ "unchecked" })
+            @Override
+            public int compare(List<Object> thisObjects, List<Object> thatObjects) {
+                if (thisObjects.size() != thatObjects.size()) {
+                    throw new AggregationExecutionException(
+                        "[" + MultiTermsAggregationBuilder.NAME + "] aggregations failed due to terms" + " size is different"
+                    );
+                }
+                for (int i = 0; i < thisObjects.size(); i++) {
+                    final Object thisObject = thisObjects.get(i);
+                    final Object thatObject = thatObjects.get(i);
+                    int ret = ((Comparable) thisObject).compareTo(thatObject);
+                    if (ret != 0) {
+                        return ret;
+                    }
+                }
+                return 0;
+            }
+        }
+    }
+
+    private final int shardSize;
+    private final boolean showTermDocCountError;
+    private final long otherDocCount;
+    private final List<DocValueFormat> termFormats;
+    private final List<Bucket> buckets;
+    private Map<String, Bucket> bucketMap;
+
+    private long docCountError;
+
+    public InternalMultiTerms(
+        String name,
+        BucketOrder reduceOrder,
+        BucketOrder order,
+        Map<String, Object> metadata,
+        int shardSize,
+        boolean showTermDocCountError,
+        long otherDocCount,
+        long docCountError,
+        List<DocValueFormat> formats,
+        List<Bucket> buckets,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
+    ) {
+        super(name, reduceOrder, order, bucketCountThresholds, metadata);
+        this.shardSize = shardSize;
+        this.showTermDocCountError = showTermDocCountError;
+        this.otherDocCount = otherDocCount;
+        this.termFormats = formats;
+        this.buckets = buckets;
+        this.docCountError = docCountError;
+    }
+
+    public InternalMultiTerms(StreamInput in) throws IOException {
+        super(in);
+        this.docCountError = in.readZLong();
+        this.termFormats = in.readList(stream -> stream.readNamedWriteable(DocValueFormat.class));
+        this.shardSize = readSize(in);
+        this.showTermDocCountError = in.readBoolean();
+        this.otherDocCount = in.readVLong();
+        this.buckets = in.readList(steam -> new Bucket(steam, termFormats, showTermDocCountError));
+    }
+
+    @Override
+    public String getWriteableName() {
+        return MultiTermsAggregationBuilder.NAME;
+    }
+
+    @Override
+    public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
+        return doXContentCommon(builder, params, docCountError, otherDocCount, buckets);
+    }
+
+    @Override
+    public InternalMultiTerms create(List<Bucket> buckets) {
+        return new InternalMultiTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            docCountError,
+            termFormats,
+            buckets,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    public Bucket createBucket(InternalAggregations aggregations, Bucket prototype) {
+        return new Bucket(
+            prototype.termValues,
+            prototype.docCount,
+            aggregations,
+            prototype.showDocCountError,
+            prototype.docCountError,
+            prototype.termFormats
+        );
+    }
+
+    @Override
+    protected void writeTermTypeInfoTo(StreamOutput out) throws IOException {
+        out.writeZLong(docCountError);
+        out.writeCollection(termFormats, StreamOutput::writeNamedWriteable);
+        writeSize(shardSize, out);
+        out.writeBoolean(showTermDocCountError);
+        out.writeVLong(otherDocCount);
+        out.writeList(buckets);
+    }
+
+    @Override
+    public List<Bucket> getBuckets() {
+        return buckets;
+    }
+
+    @Override
+    public Bucket getBucketByKey(String term) {
+        if (bucketMap == null) {
+            bucketMap = buckets.stream().collect(Collectors.toMap(InternalMultiTerms.Bucket::getKeyAsString, Function.identity()));
+        }
+        return bucketMap.get(term);
+    }
+
+    @Override
+    public long getDocCountError() {
+        return docCountError;
+    }
+
+    @Override
+    public long getSumOfOtherDocCounts() {
+        return otherDocCount;
+    }
+
+    @Override
+    protected void setDocCountError(long docCountError) {
+        this.docCountError = docCountError;
+    }
+
+    @Override
+    protected int getShardSize() {
+        return shardSize;
+    }
+
+    @Override
+    protected InternalMultiTerms create(
+        String name,
+        List<Bucket> buckets,
+        BucketOrder reduceOrder,
+        long docCountError,
+        long otherDocCount
+    ) {
+        return new InternalMultiTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            docCountError,
+            termFormats,
+            buckets,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    protected Bucket[] createBucketsArray(int size) {
+        return new Bucket[size];
+    }
+
+    @Override
+    Bucket createBucket(long docCount, InternalAggregations aggs, long docCountError, Bucket prototype) {
+        return new Bucket(
+            prototype.termValues,
+            docCount,
+            aggs,
+            prototype.showDocCountError,
+            prototype.docCountError,
+            prototype.termFormats
+        );
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        if (super.equals(obj) == false) return false;
+        InternalMultiTerms that = (InternalMultiTerms) obj;
+
+        if (showTermDocCountError && docCountError != that.docCountError) {
+            return false;
+        }
+        return Objects.equals(buckets, that.buckets)
+            && Objects.equals(otherDocCount, that.otherDocCount)
+            && Objects.equals(showTermDocCountError, that.showTermDocCountError)
+            && Objects.equals(shardSize, that.shardSize)
+            && Objects.equals(docCountError, that.docCountError);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), buckets, otherDocCount, showTermDocCountError, shardSize);
+    }
+
+    /**
+     * Copy from InternalComposite
+     *
+     * Format <code>obj</code> using the provided {@link DocValueFormat}.
+     * If the format is equals to {@link DocValueFormat#RAW}, the object is returned as is
+     * for numbers and a string for {@link BytesRef}s.
+     */
+    static Object formatObject(Object obj, DocValueFormat format) {
+        if (obj == null) {
+            return null;
+        }
+        if (obj.getClass() == BytesRef.class) {
+            BytesRef value = (BytesRef) obj;
+            if (format == DocValueFormat.RAW) {
+                return value.utf8ToString();
+            } else {
+                return format.format(value);
+            }
+        } else if (obj.getClass() == Long.class) {
+            long value = (long) obj;
+            if (format == DocValueFormat.RAW) {
+                return value;
+            } else {
+                return format.format(value);
+            }
+        } else if (obj.getClass() == Double.class) {
+            double value = (double) obj;
+            if (format == DocValueFormat.RAW) {
+                return value;
+            } else {
+                return format.format(value);
+            }
+        }
+        return obj;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalRareTerms.java
index 8f51ede1bc2a7..85d96e4978450 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalRareTerms.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.SetBackedScalingCuckooFilter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -50,17 +50,29 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of rare terms
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalRareTerms<A extends InternalRareTerms<A, B>, B extends InternalRareTerms.Bucket<B>> extends
     InternalMultiBucketAggregation<A, B>
     implements
         RareTerms {
 
+    /**
+     * Bucket for a rare terms agg
+     *
+     * @opensearch.internal
+     */
     public abstract static class Bucket<B extends Bucket<B>> extends InternalMultiBucketAggregation.InternalBucket
         implements
             RareTerms.Bucket,
             KeyComparable<B> {
         /**
          * Reads a bucket. Should be a constructor reference.
+         *
+         * @opensearch.internal
          */
         @FunctionalInterface
         public interface Reader<B extends Bucket<B>> {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTerms.java
index 4122e8b26e348..03bb519ed9961 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTerms.java
@@ -31,14 +31,15 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 
 import java.io.IOException;
@@ -51,6 +52,8 @@
 
 /**
  * Result of the significant terms aggregation.
+ *
+ * @opensearch.internal
  */
 public abstract class InternalSignificantTerms<A extends InternalSignificantTerms<A, B>, B extends InternalSignificantTerms.Bucket<B>>
     extends InternalMultiBucketAggregation<A, B>
@@ -60,12 +63,19 @@ public abstract class InternalSignificantTerms<A extends InternalSignificantTerm
     public static final String SCORE = "score";
     public static final String BG_COUNT = "bg_count";
 
+    /**
+     * Bucket for a significant terms agg
+     *
+     * @opensearch.internal
+     */
     @SuppressWarnings("PMD.ConstructorCallsOverridableMethod")
     public abstract static class Bucket<B extends Bucket<B>> extends InternalMultiBucketAggregation.InternalBucket
         implements
             SignificantTerms.Bucket {
         /**
          * Reads a bucket. Should be a constructor reference.
+         *
+         * @opensearch.internal
          */
         @FunctionalInterface
         public interface Reader<B extends Bucket<B>> {
@@ -186,11 +196,17 @@ public final XContentBuilder toXContent(XContentBuilder builder, Params params)
 
     protected final int requiredSize;
     protected final long minDocCount;
+    protected final TermsAggregator.BucketCountThresholds bucketCountThresholds;
 
-    protected InternalSignificantTerms(String name, int requiredSize, long minDocCount, Map<String, Object> metadata) {
+    protected InternalSignificantTerms(
+        String name,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
+        Map<String, Object> metadata
+    ) {
         super(name, metadata);
-        this.requiredSize = requiredSize;
-        this.minDocCount = minDocCount;
+        this.requiredSize = bucketCountThresholds.getRequiredSize();
+        this.minDocCount = bucketCountThresholds.getMinDocCount();
+        this.bucketCountThresholds = bucketCountThresholds;
     }
 
     /**
@@ -200,6 +216,9 @@ protected InternalSignificantTerms(StreamInput in) throws IOException {
         super(in);
         requiredSize = readSize(in);
         minDocCount = in.readVLong();
+        // shardMinDocCount and shardSize are not used on the coordinator, so they are not deserialized. We use
+        // CoordinatorBucketCountThresholds which will throw an exception if they are accessed.
+        bucketCountThresholds = new TermsAggregator.CoordinatorBucketCountThresholds(minDocCount, -1, requiredSize, -1);
     }
 
     protected final void doWriteTo(StreamOutput out) throws IOException {
@@ -215,6 +234,7 @@ protected final void doWriteTo(StreamOutput out) throws IOException {
 
     @Override
     public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
+        LocalBucketCountThresholds localBucketCountThresholds = reduceContext.asLocalBucketCountThresholds(bucketCountThresholds);
         long globalSubsetSize = 0;
         long globalSupersetSize = 0;
         // Compute the overall result set size and the corpus size using the
@@ -223,7 +243,13 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
             @SuppressWarnings("unchecked")
             InternalSignificantTerms<A, B> terms = (InternalSignificantTerms<A, B>) aggregation;
             globalSubsetSize += terms.getSubsetSize();
-            globalSupersetSize += terms.getSupersetSize();
+            // supersetSize is a shard level count, if we sum it across slices we would produce num_slices_with_bucket * supersetSize where
+            // num_slices_with_bucket is the number of segment slices that have collected a bucket for the key
+            if (reduceContext.isSliceLevel()) {
+                globalSupersetSize = terms.getSupersetSize();
+            } else {
+                globalSupersetSize += terms.getSupersetSize();
+            }
         }
         Map<String, List<B>> buckets = new HashMap<>();
         for (InternalAggregation aggregation : aggregations) {
@@ -250,13 +276,21 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
             }
         }
         SignificanceHeuristic heuristic = getSignificanceHeuristic().rewrite(reduceContext);
-        final int size = reduceContext.isFinalReduce() == false ? buckets.size() : Math.min(requiredSize, buckets.size());
+        boolean isCoordinatorPartialReduce = reduceContext.isFinalReduce() == false && reduceContext.isSliceLevel() == false;
+        // Do not apply size threshold on coordinator partial reduce
+        final int size = !isCoordinatorPartialReduce
+            ? Math.min(localBucketCountThresholds.getRequiredSize(), buckets.size())
+            : buckets.size();
         BucketSignificancePriorityQueue<B> ordered = new BucketSignificancePriorityQueue<>(size);
         for (Map.Entry<String, List<B>> entry : buckets.entrySet()) {
             List<B> sameTermBuckets = entry.getValue();
             final B b = reduceBucket(sameTermBuckets, reduceContext);
             b.updateScore(heuristic);
-            if (((b.score > 0) && (b.subsetDf >= minDocCount)) || reduceContext.isFinalReduce() == false) {
+            // For concurrent search case we do not apply bucket count thresholds in buildAggregation and instead is done here during
+            // reduce. However, the bucket score is only evaluated at the final coordinator reduce.
+            boolean meetsThresholds = (b.subsetDf >= localBucketCountThresholds.getMinDocCount())
+                && (((b.score > 0) || reduceContext.isSliceLevel()));
+            if (isCoordinatorPartialReduce || meetsThresholds) {
                 B removed = ordered.insertWithOverflow(b);
                 if (removed == null) {
                     reduceContext.consumeBucketsAndMaybeBreak(1);
@@ -282,7 +316,13 @@ protected B reduceBucket(List<B> buckets, ReduceContext context) {
         List<InternalAggregations> aggregationsList = new ArrayList<>(buckets.size());
         for (B bucket : buckets) {
             subsetDf += bucket.subsetDf;
-            supersetDf += bucket.supersetDf;
+            // supersetDf is a shard level count, if we sum it across slices we would produce num_slices_with_bucket * supersetSize where
+            // num_slices_with_bucket is the number of segment slices that have collected a bucket for the key
+            if (context.isSliceLevel()) {
+                supersetDf = bucket.supersetDf;
+            } else {
+                supersetDf += bucket.supersetDf;
+            }
             aggregationsList.add(bucket.aggregations);
         }
         InternalAggregations aggs = InternalAggregations.reduce(aggregationsList, context);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalTerms.java
index be397bcbb2f2c..3510b0079057b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/InternalTerms.java
@@ -33,10 +33,10 @@
 
 import org.apache.lucene.util.PriorityQueue;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregations;
@@ -47,6 +47,7 @@
 import org.opensearch.search.aggregations.InternalOrder;
 import org.opensearch.search.aggregations.KeyComparable;
 import org.opensearch.search.aggregations.bucket.IteratorAndCurrent;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
 import org.opensearch.search.aggregations.bucket.MultiBucketsAggregation;
 
 import java.io.IOException;
@@ -57,11 +58,17 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.function.Function;
 
 import static org.opensearch.search.aggregations.InternalOrder.isKeyAsc;
 import static org.opensearch.search.aggregations.InternalOrder.isKeyOrder;
 
-public abstract class InternalTerms<A extends InternalTerms<A, B>, B extends InternalTerms.Bucket<B>> extends
+/**
+ * Implementation of terms
+ *
+ * @opensearch.internal
+ */
+public abstract class InternalTerms<A extends InternalTerms<A, B>, B extends InternalTerms.AbstractInternalBucket> extends
     InternalMultiBucketAggregation<A, B>
     implements
         Terms {
@@ -69,12 +76,29 @@ public abstract class InternalTerms<A extends InternalTerms<A, B>, B extends Int
     protected static final ParseField DOC_COUNT_ERROR_UPPER_BOUND_FIELD_NAME = new ParseField("doc_count_error_upper_bound");
     protected static final ParseField SUM_OF_OTHER_DOC_COUNTS = new ParseField("sum_other_doc_count");
 
-    public abstract static class Bucket<B extends Bucket<B>> extends InternalMultiBucketAggregation.InternalBucket
-        implements
-            Terms.Bucket,
-            KeyComparable<B> {
+    /**
+     * Base internal multi bucket
+     *
+     * @opensearch.internal
+     */
+    public abstract static class AbstractInternalBucket extends InternalMultiBucketAggregation.InternalBucket implements Terms.Bucket {
+        abstract void setDocCountError(long docCountError);
+
+        abstract void setDocCountError(Function<Long, Long> updater);
+
+        abstract boolean showDocCountError();
+    }
+
+    /**
+     * Base bucket class
+     *
+     * @opensearch.internal
+     */
+    public abstract static class Bucket<B extends Bucket<B>> extends AbstractInternalBucket implements KeyComparable<B> {
         /**
          * Reads a bucket. Should be a constructor reference.
+         *
+         * @opensearch.internal
          */
         @FunctionalInterface
         public interface Reader<B extends Bucket<B>> {
@@ -142,6 +166,21 @@ public long getDocCountError() {
             return docCountError;
         }
 
+        @Override
+        public void setDocCountError(long docCountError) {
+            this.docCountError = docCountError;
+        }
+
+        @Override
+        public void setDocCountError(Function<Long, Long> updater) {
+            this.docCountError = updater.apply(this.docCountError);
+        }
+
+        @Override
+        public boolean showDocCountError() {
+            return showDocCountError;
+        }
+
         @Override
         public Aggregations getAggregations() {
             return aggregations;
@@ -186,29 +225,29 @@ public int hashCode() {
     protected final BucketOrder order;
     protected final int requiredSize;
     protected final long minDocCount;
+    protected final TermsAggregator.BucketCountThresholds bucketCountThresholds;
 
     /**
      * Creates a new {@link InternalTerms}
      * @param name The name of the aggregation
      * @param reduceOrder The {@link BucketOrder} that should be used to merge shard results.
      * @param order The {@link BucketOrder} that should be used to sort the final reduce.
-     * @param requiredSize The number of top buckets.
-     * @param minDocCount The minimum number of documents allowed per bucket.
+     * @param bucketCountThresholds Object containing values for minDocCount, shardMinDocCount, size, shardSize.
      * @param metadata The metadata associated with the aggregation.
      */
     protected InternalTerms(
         String name,
         BucketOrder reduceOrder,
         BucketOrder order,
-        int requiredSize,
-        long minDocCount,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
         Map<String, Object> metadata
     ) {
         super(name, metadata);
         this.reduceOrder = reduceOrder;
         this.order = order;
-        this.requiredSize = requiredSize;
-        this.minDocCount = minDocCount;
+        this.bucketCountThresholds = bucketCountThresholds;
+        this.requiredSize = bucketCountThresholds.getRequiredSize();
+        this.minDocCount = bucketCountThresholds.getMinDocCount();
     }
 
     /**
@@ -224,6 +263,9 @@ protected InternalTerms(StreamInput in) throws IOException {
         }
         requiredSize = readSize(in);
         minDocCount = in.readVLong();
+        // shardMinDocCount and shardSize are not used on the coordinator, so they are not deserialized. We use
+        // CoordinatorBucketCountThresholds which will throw an exception if they are accessed.
+        bucketCountThresholds = new TermsAggregator.CoordinatorBucketCountThresholds(minDocCount, -1, requiredSize, getShardSize());
     }
 
     @Override
@@ -262,9 +304,11 @@ private BucketOrder getReduceOrder(List<InternalAggregation> aggregations) {
         return thisReduceOrder != null ? thisReduceOrder : order;
     }
 
-    private long getDocCountError(InternalTerms<?, ?> terms) {
+    private long getDocCountError(InternalTerms<?, ?> terms, ReduceContext reduceContext) {
         int size = terms.getBuckets().size();
-        if (size == 0 || size < terms.getShardSize() || isKeyOrder(terms.order)) {
+        // doc_count_error is always computed at the coordinator based on the buckets returned by the shards. This should be 0 during the
+        // shard level reduce as no buckets are being pruned at this stage.
+        if (reduceContext.isSliceLevel() || size == 0 || size < terms.getShardSize() || isKeyOrder(terms.order)) {
             return 0;
         } else if (InternalOrder.isCountDesc(terms.order)) {
             if (terms.getDocCountError() > 0) {
@@ -274,7 +318,7 @@ private long getDocCountError(InternalTerms<?, ?> terms) {
             } else {
                 // otherwise use the doc count of the last term in the
                 // aggregation
-                return terms.getBuckets().stream().mapToLong(Bucket::getDocCount).min().getAsLong();
+                return terms.getBuckets().stream().mapToLong(MultiBucketsAggregation.Bucket::getDocCount).min().getAsLong();
             }
         } else {
             return -1;
@@ -354,6 +398,7 @@ private List<B> reduceLegacy(List<InternalAggregation> aggregations, ReduceConte
     }
 
     public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
+        LocalBucketCountThresholds localBucketCountThresholds = reduceContext.asLocalBucketCountThresholds(bucketCountThresholds);
         long sumDocCountError = 0;
         long otherDocCount = 0;
         InternalTerms<A, B> referenceTerms = null;
@@ -376,7 +421,7 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
                 );
             }
             otherDocCount += terms.getSumOfOtherDocCounts();
-            final long thisAggDocCountError = getDocCountError(terms);
+            final long thisAggDocCountError = getDocCountError(terms, reduceContext);
             if (sumDocCountError != -1) {
                 if (thisAggDocCountError == -1) {
                     sumDocCountError = -1;
@@ -393,7 +438,7 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
                 // for the existing error calculated in a previous reduce.
                 // Note that if the error is unbounded (-1) this will be fixed
                 // later in this method.
-                bucket.docCountError -= thisAggDocCountError;
+                bucket.setDocCountError(docCountError -> docCountError - thisAggDocCountError);
             }
         }
 
@@ -413,17 +458,18 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
             reducedBuckets = reduceLegacy(aggregations, reduceContext);
         }
         final B[] list;
-        if (reduceContext.isFinalReduce()) {
-            final int size = Math.min(requiredSize, reducedBuckets.size());
+        if (reduceContext.isFinalReduce() || reduceContext.isSliceLevel()) {
+            final int size = Math.min(localBucketCountThresholds.getRequiredSize(), reducedBuckets.size());
             // final comparator
             final BucketPriorityQueue<B> ordered = new BucketPriorityQueue<>(size, order.comparator());
             for (B bucket : reducedBuckets) {
                 if (sumDocCountError == -1) {
-                    bucket.docCountError = -1;
+                    bucket.setDocCountError(-1);
                 } else {
-                    bucket.docCountError += sumDocCountError;
+                    final long finalSumDocCountError = sumDocCountError;
+                    bucket.setDocCountError(docCountError -> docCountError + finalSumDocCountError);
                 }
-                if (bucket.docCount >= minDocCount) {
+                if (bucket.getDocCount() >= localBucketCountThresholds.getMinDocCount()) {
                     B removed = ordered.insertWithOverflow(bucket);
                     if (removed != null) {
                         otherDocCount += removed.getDocCount();
@@ -442,15 +488,18 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
         } else {
             // we can prune the list on partial reduce if the aggregation is ordered by key
             // and not filtered (minDocCount == 0)
-            int size = isKeyOrder(order) && minDocCount == 0 ? Math.min(requiredSize, reducedBuckets.size()) : reducedBuckets.size();
+            int size = isKeyOrder(order) && localBucketCountThresholds.getMinDocCount() == 0
+                ? Math.min(localBucketCountThresholds.getRequiredSize(), reducedBuckets.size())
+                : reducedBuckets.size();
             list = createBucketsArray(size);
             for (int i = 0; i < size; i++) {
                 reduceContext.consumeBucketsAndMaybeBreak(1);
                 list[i] = reducedBuckets.get(i);
                 if (sumDocCountError == -1) {
-                    list[i].docCountError = -1;
+                    list[i].setDocCountError(-1);
                 } else {
-                    list[i].docCountError += sumDocCountError;
+                    final long fSumDocCountError = sumDocCountError;
+                    list[i].setDocCountError(docCountError -> docCountError + fSumDocCountError);
                 }
             }
         }
@@ -460,6 +509,11 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
         } else {
             docCountError = aggregations.size() == 1 ? 0 : sumDocCountError;
         }
+
+        // Shards must return buckets sorted by key, so we apply the sort here in shard level reduce
+        if (reduceContext.isSliceLevel()) {
+            Arrays.sort(list, thisReduceOrder.comparator());
+        }
         return create(name, Arrays.asList(list), reduceContext.isFinalReduce() ? order : thisReduceOrder, docCountError, otherDocCount);
     }
 
@@ -474,15 +528,15 @@ protected B reduceBucket(List<B> buckets, ReduceContext context) {
         long docCountError = 0;
         List<InternalAggregations> aggregationsList = new ArrayList<>(buckets.size());
         for (B bucket : buckets) {
-            docCount += bucket.docCount;
+            docCount += bucket.getDocCount();
             if (docCountError != -1) {
-                if (bucket.docCountError == -1) {
+                if (bucket.showDocCountError() == false || bucket.getDocCountError() == -1) {
                     docCountError = -1;
                 } else {
-                    docCountError += bucket.docCountError;
+                    docCountError += bucket.getDocCountError();
                 }
             }
-            aggregationsList.add(bucket.aggregations);
+            aggregationsList.add((InternalAggregations) bucket.getAggregations());
         }
         InternalAggregations aggs = InternalAggregations.reduce(aggregationsList, context);
         return createBucket(docCount, aggs, docCountError, buckets.get(0));
@@ -524,12 +578,12 @@ protected static XContentBuilder doXContentCommon(
         Params params,
         long docCountError,
         long otherDocCount,
-        List<? extends Bucket> buckets
+        List<? extends AbstractInternalBucket> buckets
     ) throws IOException {
         builder.field(DOC_COUNT_ERROR_UPPER_BOUND_FIELD_NAME.getPreferredName(), docCountError);
         builder.field(SUM_OF_OTHER_DOC_COUNTS.getPreferredName(), otherDocCount);
         builder.startArray(CommonFields.BUCKETS.getPreferredName());
-        for (Bucket bucket : buckets) {
+        for (AbstractInternalBucket bucket : buckets) {
             bucket.toXContent(builder, params);
         }
         builder.endArray();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrds.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrds.java
index 0964d8aa8adb7..dd4ddfdb0f9df 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrds.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrds.java
@@ -34,12 +34,14 @@
 
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.LongHash;
 import org.opensearch.common.util.LongLongHash;
+import org.opensearch.common.util.ReorganizingLongHash;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
 
 /**
  * Maps long bucket keys to bucket ordinals.
+ *
+ * @opensearch.internal
  */
 public abstract class LongKeyedBucketOrds implements Releasable {
     /**
@@ -98,6 +100,8 @@ private LongKeyedBucketOrds() {}
 
     /**
      * An iterator for buckets inside a particular {@code owningBucketOrd}.
+     *
+     * @opensearch.internal
      */
     public interface BucketOrdsEnum {
         /**
@@ -140,12 +144,14 @@ public long value() {
 
     /**
      * Implementation that only works if it is collecting from a single bucket.
+     *
+     * @opensearch.internal
      */
     public static class FromSingle extends LongKeyedBucketOrds {
-        private final LongHash ords;
+        private final ReorganizingLongHash ords;
 
         public FromSingle(BigArrays bigArrays) {
-            ords = new LongHash(1, bigArrays);
+            ords = new ReorganizingLongHash(bigArrays);
         }
 
         @Override
@@ -219,6 +225,8 @@ public void close() {
 
     /**
      * Implementation that works properly when collecting from many buckets.
+     *
+     * @opensearch.internal
      */
     public static class FromMany extends LongKeyedBucketOrds {
         private final LongLongHash ords;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTerms.java
index f8ea5c4231cac..a2f8af0bfe69f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTerms.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.SetBackedScalingCuckooFilter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -46,10 +46,17 @@
 
 /**
  * Result of the RareTerms aggregation when the field is some kind of whole number like a integer, long, or a date.
+ *
+ * @opensearch.internal
  */
 public class LongRareTerms extends InternalMappedRareTerms<LongRareTerms, LongRareTerms.Bucket> {
     public static final String NAME = "lrareterms";
 
+    /**
+     * Bucket for rare long valued terms
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalRareTerms.Bucket<Bucket> {
         long term;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTermsAggregator.java
index 1a44c41c1f15f..6e4cd895e7496 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongRareTermsAggregator.java
@@ -56,6 +56,8 @@
 
 /**
  * An aggregator that finds "rare" string values (e.g. terms agg that orders ascending)
+ *
+ * @opensearch.internal
  */
 public class LongRareTermsAggregator extends AbstractRareTermsAggregator {
     private final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongTerms.java
index 265fa532574be..fe78145dce3e7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/LongTerms.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -47,10 +47,17 @@
 
 /**
  * Result of the {@link TermsAggregator} when the field is some kind of whole number like a integer, long, or a date.
+ *
+ * @opensearch.internal
  */
 public class LongTerms extends InternalMappedTerms<LongTerms, LongTerms.Bucket> {
     public static final String NAME = "lterms";
 
+    /**
+     * Bucket for long terms
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalTerms.Bucket<Bucket> {
         long term;
 
@@ -135,29 +142,27 @@ public LongTerms(
         String name,
         BucketOrder reduceOrder,
         BucketOrder order,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         int shardSize,
         boolean showTermDocCountError,
         long otherDocCount,
         List<Bucket> buckets,
-        long docCountError
+        long docCountError,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
         super(
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -179,15 +184,14 @@ public LongTerms create(List<Bucket> buckets) {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -209,15 +213,14 @@ protected LongTerms create(String name, List<Bucket> buckets, BucketOrder reduce
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             getMetadata(),
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -239,6 +242,8 @@ public InternalAggregation reduce(List<InternalAggregation> aggregations, Reduce
                     rawFormat = true;
                 } else if (((LongTerms) agg).format == DocValueFormat.UNSIGNED_LONG_SHIFTED) {
                     unsignedLongFormat = true;
+                } else if (((LongTerms) agg).format == DocValueFormat.UNSIGNED_LONG) {
+                    unsignedLongFormat = true;
                 }
             }
         }
@@ -284,15 +289,14 @@ static DoubleTerms convertLongTermsToDouble(LongTerms longTerms, DocValueFormat
             longTerms.getName(),
             longTerms.reduceOrder,
             longTerms.order,
-            longTerms.requiredSize,
-            longTerms.minDocCount,
             longTerms.metadata,
             longTerms.format,
             longTerms.shardSize,
             longTerms.showTermDocCountError,
             longTerms.otherDocCount,
             newBuckets,
-            longTerms.docCountError
+            longTerms.docCountError,
+            longTerms.bucketCountThresholds
         );
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MapStringTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MapStringTermsAggregator.java
index a1c7d22bd29e0..ade23f7290f89 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MapStringTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MapStringTermsAggregator.java
@@ -50,6 +50,7 @@
 import org.opensearch.search.aggregations.InternalOrder;
 import org.opensearch.search.aggregations.LeafBucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollectorBase;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
 import org.opensearch.search.aggregations.bucket.terms.SignificanceLookup.BackgroundFrequencyForBytes;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 import org.opensearch.search.aggregations.support.ValuesSource;
@@ -68,6 +69,8 @@
 /**
  * An aggregator of string values that hashes the strings on the fly rather
  * than up front like the {@link GlobalOrdinalsStringTermsAggregator}.
+ *
+ * @opensearch.internal
  */
 public class MapStringTermsAggregator extends AbstractStringTermsAggregator {
     private final CollectorSource collectorSource;
@@ -151,6 +154,8 @@ public void doClose() {
 
     /**
      * Abstaction on top of building collectors to fetch values.
+     *
+     * @opensearch.internal
      */
     public interface CollectorSource extends Releasable {
         boolean needsScores();
@@ -164,6 +169,11 @@ LeafBucketCollector getLeafCollector(
         ) throws IOException;
     }
 
+    /**
+     * Consumer for the collector
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     public interface CollectConsumer {
         void accept(LeafBucketCollector sub, int doc, long owningBucketOrd, BytesRef bytes) throws IOException;
@@ -171,6 +181,8 @@ public interface CollectConsumer {
 
     /**
      * Fetch values from a {@link ValuesSource}.
+     *
+     * @opensearch.internal
      */
     public static class ValuesSourceCollectorSource implements CollectorSource {
         private final ValuesSource valuesSource;
@@ -233,11 +245,12 @@ abstract class ResultStrategy<R extends InternalAggregation, B extends InternalM
             Releasable {
 
         private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
+            LocalBucketCountThresholds localBucketCountThresholds = context.asLocalBucketCountThresholds(bucketCountThresholds);
             B[][] topBucketsPerOrd = buildTopBucketsPerOrd(owningBucketOrds.length);
             long[] otherDocCounts = new long[owningBucketOrds.length];
             for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
                 collectZeroDocEntriesIfNeeded(owningBucketOrds[ordIdx]);
-                int size = (int) Math.min(bucketOrds.size(), bucketCountThresholds.getShardSize());
+                int size = (int) Math.min(bucketOrds.size(), localBucketCountThresholds.getRequiredSize());
 
                 PriorityQueue<B> ordered = buildPriorityQueue(size);
                 B spare = null;
@@ -246,7 +259,7 @@ private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws
                 while (ordsEnum.next()) {
                     long docCount = bucketDocCount(ordsEnum.ord());
                     otherDocCounts[ordIdx] += docCount;
-                    if (docCount < bucketCountThresholds.getShardMinDocCount()) {
+                    if (docCount < localBucketCountThresholds.getMinDocCount()) {
                         continue;
                     }
                     if (spare == null) {
@@ -443,15 +456,14 @@ StringTerms buildResult(long owningBucketOrd, long otherDocCount, StringTerms.Bu
                 name,
                 reduceOrder,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 otherDocCount,
                 Arrays.asList(topBuckets),
-                0
+                0,
+                bucketCountThresholds
             );
         }
 
@@ -561,14 +573,13 @@ void buildSubAggs(SignificantStringTerms.Bucket[][] topBucketsPerOrd) throws IOE
         SignificantStringTerms buildResult(long owningBucketOrd, long otherDocCount, SignificantStringTerms.Bucket[] topBuckets) {
             return new SignificantStringTerms(
                 name,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 subsetSizes.get(owningBucketOrd),
                 supersetSize,
                 significanceHeuristic,
-                Arrays.asList(topBuckets)
+                Arrays.asList(topBuckets),
+                bucketCountThresholds
             );
         }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilder.java
new file mode 100644
index 0000000000000..c711b140be192
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilder.java
@@ -0,0 +1,445 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.search.aggregations.AbstractAggregationBuilder;
+import org.opensearch.search.aggregations.AggregationBuilder;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.AggregatorFactories;
+import org.opensearch.search.aggregations.AggregatorFactory;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalOrder;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import static org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder.DEFAULT_BUCKET_COUNT_THRESHOLDS;
+
+/**
+ * Multi-terms aggregation supports collecting terms from multiple fields in the same document.
+ *
+ * <p>
+ *   For example, using the multi-terms aggregation to group by two fields region, host, calculate max cpu, and sort by max cpu.
+ * </p>
+ * <pre>
+ *   GET test_000001/_search
+ *   {
+ *     "size": 0,
+ *     "aggs": {
+ *       "hot": {
+ *         "multi_terms": {
+ *           "terms": [{
+ *             "field": "region"
+ *           },{
+ *             "field": "host"
+ *           }],
+ *           "order": {"max-cpu": "desc"}
+ *         },
+ *         "aggs": {
+ *           "max-cpu": { "max": { "field": "cpu" } }
+ *         }
+ *       }
+ *     }
+ *   }
+ * </pre>
+ *
+ * <p>
+ *   The aggregation result contains
+ *     - key: a list of value extract from multiple fields in the same doc.
+ * </p>
+ * <pre>
+ *   {
+ *     "hot": {
+ *       "doc_count_error_upper_bound": 0,
+ *       "sum_other_doc_count": 0,
+ *       "buckets": [
+ *         {
+ *           "key": [
+ *             "dub",
+ *             "h1"
+ *           ],
+ *           "key_as_string": "dub|h1",
+ *           "doc_count": 2,
+ *           "max-cpu": {
+ *             "value": 90.0
+ *           }
+ *         },
+ *         {
+ *           "key": [
+ *             "dub",
+ *             "h2"
+ *           ],
+ *           "key_as_string": "dub|h2",
+ *           "doc_count": 2,
+ *           "max-cpu": {
+ *             "value": 70.0
+ *           }
+ *         }
+ *       ]
+ *     }
+ *   }
+ * </pre>
+ *
+ * <p>
+ *   <b>Notes:</b> The current implementation focuses on adding new type aggregates. Performance (latency) is not good，mainly because of
+ *   simply encoding/decoding a list of values as bucket keys.
+ * </p>
+ *
+ * @opensearch.internal
+ */
+public class MultiTermsAggregationBuilder extends AbstractAggregationBuilder<MultiTermsAggregationBuilder> {
+    public static final String NAME = "multi_terms";
+    public static final ObjectParser<MultiTermsAggregationBuilder, String> PARSER = ObjectParser.fromBuilder(
+        NAME,
+        MultiTermsAggregationBuilder::new
+    );
+
+    public static final ParseField TERMS_FIELD = new ParseField("terms");
+    public static final ParseField SHARD_SIZE_FIELD_NAME = new ParseField("shard_size");
+    public static final ParseField MIN_DOC_COUNT_FIELD_NAME = new ParseField("min_doc_count");
+    public static final ParseField SHARD_MIN_DOC_COUNT_FIELD_NAME = new ParseField("shard_min_doc_count");
+    public static final ParseField REQUIRED_SIZE_FIELD_NAME = new ParseField("size");
+    public static final ParseField SHOW_TERM_DOC_COUNT_ERROR = new ParseField("show_term_doc_count_error");
+    public static final ParseField ORDER_FIELD = new ParseField("order");
+
+    @Override
+    public String getType() {
+        return NAME;
+    }
+
+    static {
+        final ObjectParser<MultiTermsValuesSourceConfig.Builder, Void> parser = MultiTermsValuesSourceConfig.PARSER.apply(
+            true,
+            true,
+            true,
+            true
+        );
+        PARSER.declareObjectArray(MultiTermsAggregationBuilder::terms, (p, c) -> parser.parse(p, null).build(), TERMS_FIELD);
+
+        PARSER.declareBoolean(MultiTermsAggregationBuilder::showTermDocCountError, SHOW_TERM_DOC_COUNT_ERROR);
+
+        PARSER.declareInt(MultiTermsAggregationBuilder::shardSize, SHARD_SIZE_FIELD_NAME);
+
+        PARSER.declareLong(MultiTermsAggregationBuilder::minDocCount, MIN_DOC_COUNT_FIELD_NAME);
+
+        PARSER.declareLong(MultiTermsAggregationBuilder::shardMinDocCount, SHARD_MIN_DOC_COUNT_FIELD_NAME);
+
+        PARSER.declareInt(MultiTermsAggregationBuilder::size, REQUIRED_SIZE_FIELD_NAME);
+
+        PARSER.declareObjectArray(MultiTermsAggregationBuilder::order, (p, c) -> InternalOrder.Parser.parseOrderParam(p), ORDER_FIELD);
+
+        PARSER.declareField(
+            MultiTermsAggregationBuilder::collectMode,
+            (p, c) -> Aggregator.SubAggCollectionMode.parse(p.text(), LoggingDeprecationHandler.INSTANCE),
+            Aggregator.SubAggCollectionMode.KEY,
+            ObjectParser.ValueType.STRING
+        );
+    }
+
+    public static final ValuesSourceRegistry.RegistryKey<MultiTermsAggregationFactory.InternalValuesSourceSupplier> REGISTRY_KEY =
+        new ValuesSourceRegistry.RegistryKey<>(
+            MultiTermsAggregationBuilder.NAME,
+            MultiTermsAggregationFactory.InternalValuesSourceSupplier.class
+        );
+
+    private List<MultiTermsValuesSourceConfig> terms;
+
+    private BucketOrder order = BucketOrder.compound(BucketOrder.count(false)); // automatically adds tie-breaker key asc order
+    private Aggregator.SubAggCollectionMode collectMode = null;
+    private TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+        DEFAULT_BUCKET_COUNT_THRESHOLDS
+    );
+    private boolean showTermDocCountError = false;
+
+    public MultiTermsAggregationBuilder(String name) {
+        super(name);
+    }
+
+    protected MultiTermsAggregationBuilder(
+        MultiTermsAggregationBuilder clone,
+        AggregatorFactories.Builder factoriesBuilder,
+        Map<String, Object> metadata
+    ) {
+        super(clone, factoriesBuilder, metadata);
+        this.terms = new ArrayList<>(clone.terms);
+        this.order = clone.order;
+        this.collectMode = clone.collectMode;
+        this.bucketCountThresholds = new TermsAggregator.BucketCountThresholds(clone.bucketCountThresholds);
+        this.showTermDocCountError = clone.showTermDocCountError;
+    }
+
+    @Override
+    protected AggregationBuilder shallowCopy(AggregatorFactories.Builder factoriesBuilder, Map<String, Object> metadata) {
+        return new MultiTermsAggregationBuilder(this, factoriesBuilder, metadata);
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public MultiTermsAggregationBuilder(StreamInput in) throws IOException {
+        super(in);
+        terms = in.readList(MultiTermsValuesSourceConfig::new);
+        bucketCountThresholds = new TermsAggregator.BucketCountThresholds(in);
+        collectMode = in.readOptionalWriteable(Aggregator.SubAggCollectionMode::readFromStream);
+        order = InternalOrder.Streams.readOrder(in);
+        showTermDocCountError = in.readBoolean();
+    }
+
+    @Override
+    protected void doWriteTo(StreamOutput out) throws IOException {
+        out.writeList(terms);
+        bucketCountThresholds.writeTo(out);
+        out.writeOptionalWriteable(collectMode);
+        order.writeTo(out);
+        out.writeBoolean(showTermDocCountError);
+    }
+
+    @Override
+    protected AggregatorFactory doBuild(
+        QueryShardContext queryShardContext,
+        AggregatorFactory parent,
+        AggregatorFactories.Builder subfactoriesBuilder
+    ) throws IOException {
+        return new MultiTermsAggregationFactory(
+            name,
+            queryShardContext,
+            parent,
+            subfactoriesBuilder,
+            metadata,
+            terms,
+            order,
+            collectMode,
+            bucketCountThresholds,
+            showTermDocCountError
+        );
+    }
+
+    @Override
+    protected XContentBuilder internalXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (terms != null) {
+            builder.field(TERMS_FIELD.getPreferredName(), terms);
+        }
+        bucketCountThresholds.toXContent(builder, params);
+        builder.field(SHOW_TERM_DOC_COUNT_ERROR.getPreferredName(), showTermDocCountError);
+        builder.field(ORDER_FIELD.getPreferredName());
+        order.toXContent(builder, params);
+        if (collectMode != null) {
+            builder.field(Aggregator.SubAggCollectionMode.KEY.getPreferredName(), collectMode.parseField().getPreferredName());
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * Set the terms.
+     */
+    public MultiTermsAggregationBuilder terms(List<MultiTermsValuesSourceConfig> terms) {
+        if (terms == null) {
+            throw new IllegalArgumentException("[terms] must not be null. Found null terms in [" + name + "]");
+        }
+        if (terms.size() < 2) {
+            throw new IllegalArgumentException(
+                "multi term aggregation must has at least 2 terms. Found ["
+                    + terms.size()
+                    + "] in"
+                    + " ["
+                    + name
+                    + "]"
+                    + (terms.size() == 1 ? " Use terms aggregation for single term aggregation" : "")
+            );
+        }
+        this.terms = terms;
+        return this;
+    }
+
+    /**
+     * Sets the size - indicating how many term buckets should be returned
+     * (defaults to 10)
+     */
+    public MultiTermsAggregationBuilder size(int size) {
+        if (size <= 0) {
+            throw new IllegalArgumentException("[size] must be greater than 0. Found [" + size + "] in [" + name + "]");
+        }
+        bucketCountThresholds.setRequiredSize(size);
+        return this;
+    }
+
+    /**
+     * Returns the number of term buckets currently configured
+     */
+    public int size() {
+        return bucketCountThresholds.getRequiredSize();
+    }
+
+    /**
+     * Sets the shard_size - indicating the number of term buckets each shard
+     * will return to the coordinating node (the node that coordinates the
+     * search execution). The higher the shard size is, the more accurate the
+     * results are.
+     */
+    public MultiTermsAggregationBuilder shardSize(int shardSize) {
+        if (shardSize <= 0) {
+            throw new IllegalArgumentException("[shardSize] must be greater than 0. Found [" + shardSize + "] in [" + name + "]");
+        }
+        bucketCountThresholds.setShardSize(shardSize);
+        return this;
+    }
+
+    /**
+     * Returns the number of term buckets per shard that are currently configured
+     */
+    public int shardSize() {
+        return bucketCountThresholds.getShardSize();
+    }
+
+    /**
+     * Set the minimum document count terms should have in order to appear in
+     * the response.
+     */
+    public MultiTermsAggregationBuilder minDocCount(long minDocCount) {
+        if (minDocCount < 0) {
+            throw new IllegalArgumentException(
+                "[minDocCount] must be greater than or equal to 0. Found [" + minDocCount + "] in [" + name + "]"
+            );
+        }
+        bucketCountThresholds.setMinDocCount(minDocCount);
+        return this;
+    }
+
+    /**
+     * Returns the minimum document count required per term
+     */
+    public long minDocCount() {
+        return bucketCountThresholds.getMinDocCount();
+    }
+
+    /**
+     * Set the minimum document count terms should have on the shard in order to
+     * appear in the response.
+     */
+    public MultiTermsAggregationBuilder shardMinDocCount(long shardMinDocCount) {
+        if (shardMinDocCount < 0) {
+            throw new IllegalArgumentException(
+                "[shardMinDocCount] must be greater than or equal to 0. Found [" + shardMinDocCount + "] in [" + name + "]"
+            );
+        }
+        bucketCountThresholds.setShardMinDocCount(shardMinDocCount);
+        return this;
+    }
+
+    /**
+     * Returns the minimum document count required per term, per shard
+     */
+    public long shardMinDocCount() {
+        return bucketCountThresholds.getShardMinDocCount();
+    }
+
+    /** Set a new order on this builder and return the builder so that calls
+     *  can be chained. A tie-breaker may be added to avoid non-deterministic ordering. */
+    public MultiTermsAggregationBuilder order(BucketOrder order) {
+        if (order == null) {
+            throw new IllegalArgumentException("[order] must not be null: [" + name + "]");
+        }
+        if (order instanceof InternalOrder.CompoundOrder || InternalOrder.isKeyOrder(order)) {
+            this.order = order; // if order already contains a tie-breaker we are good to go
+        } else { // otherwise add a tie-breaker by using a compound order
+            this.order = BucketOrder.compound(order);
+        }
+        return this;
+    }
+
+    /**
+     * Sets the order in which the buckets will be returned. A tie-breaker may be added to avoid non-deterministic
+     * ordering.
+     */
+    public MultiTermsAggregationBuilder order(List<BucketOrder> orders) {
+        if (orders == null) {
+            throw new IllegalArgumentException("[orders] must not be null: [" + name + "]");
+        }
+        // if the list only contains one order use that to avoid inconsistent xcontent
+        order(orders.size() > 1 ? BucketOrder.compound(orders) : orders.get(0));
+        return this;
+    }
+
+    /**
+     * Gets the order in which the buckets will be returned.
+     */
+    public BucketOrder order() {
+        return order;
+    }
+
+    /**
+     * Expert: set the collection mode.
+     */
+    public MultiTermsAggregationBuilder collectMode(Aggregator.SubAggCollectionMode collectMode) {
+        if (collectMode == null) {
+            throw new IllegalArgumentException("[collectMode] must not be null: [" + name + "]");
+        }
+        this.collectMode = collectMode;
+        return this;
+    }
+
+    /**
+     * Expert: get the collection mode.
+     */
+    public Aggregator.SubAggCollectionMode collectMode() {
+        return collectMode;
+    }
+
+    /**
+     * Get whether doc count error will be return for individual terms
+     */
+    public boolean showTermDocCountError() {
+        return showTermDocCountError;
+    }
+
+    /**
+     * Set whether doc count error will be return for individual terms
+     */
+    public MultiTermsAggregationBuilder showTermDocCountError(boolean showTermDocCountError) {
+        this.showTermDocCountError = showTermDocCountError;
+        return this;
+    }
+
+    @Override
+    public BucketCardinality bucketCardinality() {
+        return BucketCardinality.MANY;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), bucketCountThresholds, collectMode, order, showTermDocCountError);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        if (super.equals(obj) == false) return false;
+        MultiTermsAggregationBuilder other = (MultiTermsAggregationBuilder) obj;
+        return Objects.equals(terms, other.terms)
+            && Objects.equals(bucketCountThresholds, other.bucketCountThresholds)
+            && Objects.equals(collectMode, other.collectMode)
+            && Objects.equals(order, other.order)
+            && Objects.equals(showTermDocCountError, other.showTermDocCountError);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationFactory.java
new file mode 100644
index 0000000000000..7134999e4aa85
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationFactory.java
@@ -0,0 +1,173 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.AggregatorFactories;
+import org.opensearch.search.aggregations.AggregatorFactory;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
+import org.opensearch.search.aggregations.InternalOrder;
+import org.opensearch.search.aggregations.bucket.BucketUtils;
+import org.opensearch.search.aggregations.support.CoreValuesSourceType;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValuesSource;
+import org.opensearch.search.aggregations.support.ValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder.REGISTRY_KEY;
+
+/**
+ * Factory of {@link MultiTermsAggregator}.
+ *
+ * @opensearch.internal
+ */
+public class MultiTermsAggregationFactory extends AggregatorFactory {
+
+    private final List<Tuple<ValuesSourceConfig, IncludeExclude>> configs;
+    private final List<DocValueFormat> formats;
+    /**
+     * Fields inherent from Terms Aggregation Factory.
+     */
+    private final BucketOrder order;
+    private final Aggregator.SubAggCollectionMode collectMode;
+    private final TermsAggregator.BucketCountThresholds bucketCountThresholds;
+    private final boolean showTermDocCountError;
+
+    public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
+        builder.register(REGISTRY_KEY, List.of(CoreValuesSourceType.BYTES, CoreValuesSourceType.IP), config -> {
+            final IncludeExclude.StringFilter filter = config.v2() == null ? null : config.v2().convertToStringFilter(config.v1().format());
+            return MultiTermsAggregator.InternalValuesSourceFactory.bytesValuesSource(config.v1().getValuesSource(), filter);
+        }, true);
+
+        builder.register(
+            REGISTRY_KEY,
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.BOOLEAN, CoreValuesSourceType.DATE),
+            config -> {
+                ValuesSourceConfig valuesSourceConfig = config.v1();
+                IncludeExclude includeExclude = config.v2();
+                ValuesSource.Numeric valuesSource = ((ValuesSource.Numeric) valuesSourceConfig.getValuesSource());
+                IncludeExclude.LongFilter longFilter = null;
+                if (valuesSource.isFloatingPoint()) {
+                    if (includeExclude != null) {
+                        longFilter = includeExclude.convertToDoubleFilter();
+                    }
+                    return MultiTermsAggregator.InternalValuesSourceFactory.doubleValueSource(valuesSource, longFilter);
+                } else if (valuesSource.isBigInteger()) {
+                    if (includeExclude != null) {
+                        longFilter = includeExclude.convertToDoubleFilter();
+                    }
+                    return MultiTermsAggregator.InternalValuesSourceFactory.unsignedLongValuesSource(valuesSource, longFilter);
+                } else {
+                    if (includeExclude != null) {
+                        longFilter = includeExclude.convertToLongFilter(valuesSourceConfig.format());
+                    }
+                    return MultiTermsAggregator.InternalValuesSourceFactory.longValuesSource(valuesSource, longFilter);
+                }
+            },
+            true
+        );
+
+        builder.registerUsage(MultiTermsAggregationBuilder.NAME);
+    }
+
+    public MultiTermsAggregationFactory(
+        String name,
+        QueryShardContext queryShardContext,
+        AggregatorFactory parent,
+        AggregatorFactories.Builder subFactoriesBuilder,
+        Map<String, Object> metadata,
+        List<MultiTermsValuesSourceConfig> multiTermConfigs,
+        BucketOrder order,
+        Aggregator.SubAggCollectionMode collectMode,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
+        boolean showTermDocCountError
+    ) throws IOException {
+        super(name, queryShardContext, parent, subFactoriesBuilder, metadata);
+        this.configs = multiTermConfigs.stream()
+            .map(
+                c -> new Tuple<ValuesSourceConfig, IncludeExclude>(
+                    ValuesSourceConfig.resolveUnregistered(
+                        queryShardContext,
+                        c.getUserValueTypeHint(),
+                        c.getFieldName(),
+                        c.getScript(),
+                        c.getMissing(),
+                        c.getTimeZone(),
+                        c.getFormat(),
+                        CoreValuesSourceType.BYTES
+                    ),
+                    c.getIncludeExclude()
+                )
+            )
+            .collect(Collectors.toList());
+        this.formats = this.configs.stream().map(c -> c.v1().format()).collect(Collectors.toList());
+        this.order = order;
+        this.collectMode = collectMode;
+        this.bucketCountThresholds = bucketCountThresholds;
+        this.showTermDocCountError = showTermDocCountError;
+    }
+
+    @Override
+    protected Aggregator createInternal(
+        SearchContext searchContext,
+        Aggregator parent,
+        CardinalityUpperBound cardinality,
+        Map<String, Object> metadata
+    ) throws IOException {
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(this.bucketCountThresholds);
+        if (InternalOrder.isKeyOrder(order) == false
+            && bucketCountThresholds.getShardSize() == TermsAggregationBuilder.DEFAULT_BUCKET_COUNT_THRESHOLDS.getShardSize()) {
+            // The user has not made a shardSize selection. Use default
+            // heuristic to avoid any wrong-ranking caused by distributed
+            // counting
+            bucketCountThresholds.setShardSize(BucketUtils.suggestShardSideQueueSize(bucketCountThresholds.getRequiredSize()));
+        }
+        bucketCountThresholds.ensureValidity();
+        return new MultiTermsAggregator(
+            name,
+            factories,
+            showTermDocCountError,
+            configs.stream()
+                .map(config -> queryShardContext.getValuesSourceRegistry().getAggregator(REGISTRY_KEY, config.v1()).build(config))
+                .collect(Collectors.toList()),
+            configs.stream().map(c -> c.v1().format()).collect(Collectors.toList()),
+            order,
+            collectMode,
+            bucketCountThresholds,
+            searchContext,
+            parent,
+            cardinality,
+            metadata
+        );
+    }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
+    /**
+     * Supplier for internal values source
+     *
+     * @opensearch.internal
+     */
+    public interface InternalValuesSourceSupplier {
+        MultiTermsAggregator.InternalValuesSource build(Tuple<ValuesSourceConfig, IncludeExclude> config);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregator.java
new file mode 100644
index 0000000000000..0482ef823818c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregator.java
@@ -0,0 +1,528 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.NumericUtils;
+import org.apache.lucene.util.PriorityQueue;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.CheckedSupplier;
+import org.opensearch.common.Numbers;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lease.Releasables;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.index.fielddata.SortedBinaryDocValues;
+import org.opensearch.index.fielddata.SortedNumericDoubleValues;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.AggregatorFactories;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.InternalOrder;
+import org.opensearch.search.aggregations.LeafBucketCollector;
+import org.opensearch.search.aggregations.bucket.DeferableBucketAggregator;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
+import org.opensearch.search.aggregations.support.AggregationPath;
+import org.opensearch.search.aggregations.support.ValuesSource;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.opensearch.search.aggregations.InternalOrder.isKeyOrder;
+import static org.opensearch.search.aggregations.bucket.terms.TermsAggregator.descendsFromNestedAggregator;
+
+/**
+ * An aggregator that aggregate with multi_terms.
+ *
+ * @opensearch.internal
+ */
+public class MultiTermsAggregator extends DeferableBucketAggregator {
+
+    private final BytesKeyedBucketOrds bucketOrds;
+    private final MultiTermsValuesSource multiTermsValue;
+    private final boolean showTermDocCountError;
+    private final List<DocValueFormat> formats;
+    private final TermsAggregator.BucketCountThresholds bucketCountThresholds;
+    private final BucketOrder order;
+    private final Comparator<InternalMultiTerms.Bucket> partiallyBuiltBucketComparator;
+    private final SubAggCollectionMode collectMode;
+    private final Set<Aggregator> aggsUsedForSorting = new HashSet<>();
+
+    public MultiTermsAggregator(
+        String name,
+        AggregatorFactories factories,
+        boolean showTermDocCountError,
+        List<InternalValuesSource> internalValuesSources,
+        List<DocValueFormat> formats,
+        BucketOrder order,
+        SubAggCollectionMode collectMode,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
+        SearchContext context,
+        Aggregator parent,
+        CardinalityUpperBound cardinality,
+        Map<String, Object> metadata
+    ) throws IOException {
+        super(name, factories, context, parent, metadata);
+        this.bucketOrds = BytesKeyedBucketOrds.build(context.bigArrays(), cardinality);
+        this.multiTermsValue = new MultiTermsValuesSource(internalValuesSources);
+        this.showTermDocCountError = showTermDocCountError;
+        this.formats = formats;
+        this.bucketCountThresholds = bucketCountThresholds;
+        this.order = order;
+        this.partiallyBuiltBucketComparator = order == null ? null : order.partiallyBuiltBucketComparator(b -> b.bucketOrd, this);
+        // Todo, copy from TermsAggregator. need to remove duplicate code.
+        if (subAggsNeedScore() && descendsFromNestedAggregator(parent)) {
+            /**
+             * Force the execution to depth_first because we need to access the score of
+             * nested documents in a sub-aggregation and we are not able to generate this score
+             * while replaying deferred documents.
+             */
+            this.collectMode = SubAggCollectionMode.DEPTH_FIRST;
+        } else {
+            this.collectMode = collectMode;
+        }
+        // Don't defer any child agg if we are dependent on it for pruning results
+        if (order instanceof InternalOrder.Aggregation) {
+            AggregationPath path = ((InternalOrder.Aggregation) order).path();
+            aggsUsedForSorting.add(path.resolveTopmostAggregator(this));
+        } else if (order instanceof InternalOrder.CompoundOrder) {
+            InternalOrder.CompoundOrder compoundOrder = (InternalOrder.CompoundOrder) order;
+            for (BucketOrder orderElement : compoundOrder.orderElements()) {
+                if (orderElement instanceof InternalOrder.Aggregation) {
+                    AggregationPath path = ((InternalOrder.Aggregation) orderElement).path();
+                    aggsUsedForSorting.add(path.resolveTopmostAggregator(this));
+                }
+            }
+        }
+    }
+
+    @Override
+    public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
+        LocalBucketCountThresholds localBucketCountThresholds = context.asLocalBucketCountThresholds(bucketCountThresholds);
+        InternalMultiTerms.Bucket[][] topBucketsPerOrd = new InternalMultiTerms.Bucket[owningBucketOrds.length][];
+        long[] otherDocCounts = new long[owningBucketOrds.length];
+        for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
+            collectZeroDocEntriesIfNeeded(owningBucketOrds[ordIdx]);
+            long bucketsInOrd = bucketOrds.bucketsInOrd(owningBucketOrds[ordIdx]);
+
+            int size = (int) Math.min(bucketsInOrd, localBucketCountThresholds.getRequiredSize());
+            PriorityQueue<InternalMultiTerms.Bucket> ordered = new BucketPriorityQueue<>(size, partiallyBuiltBucketComparator);
+            InternalMultiTerms.Bucket spare = null;
+            BytesRef dest = null;
+            BytesKeyedBucketOrds.BucketOrdsEnum ordsEnum = bucketOrds.ordsEnum(owningBucketOrds[ordIdx]);
+            CheckedSupplier<InternalMultiTerms.Bucket, IOException> emptyBucketBuilder = () -> InternalMultiTerms.Bucket.EMPTY(
+                showTermDocCountError,
+                formats
+            );
+            while (ordsEnum.next()) {
+                long docCount = bucketDocCount(ordsEnum.ord());
+                otherDocCounts[ordIdx] += docCount;
+                if (docCount < localBucketCountThresholds.getMinDocCount()) {
+                    continue;
+                }
+                if (spare == null) {
+                    spare = emptyBucketBuilder.get();
+                    dest = new BytesRef();
+                }
+
+                ordsEnum.readValue(dest);
+
+                spare.termValues = decode(dest);
+                spare.docCount = docCount;
+                spare.bucketOrd = ordsEnum.ord();
+                spare = ordered.insertWithOverflow(spare);
+            }
+
+            // Get the top buckets
+            InternalMultiTerms.Bucket[] bucketsForOrd = new InternalMultiTerms.Bucket[ordered.size()];
+            topBucketsPerOrd[ordIdx] = bucketsForOrd;
+            for (int b = ordered.size() - 1; b >= 0; --b) {
+                topBucketsPerOrd[ordIdx][b] = ordered.pop();
+                otherDocCounts[ordIdx] -= topBucketsPerOrd[ordIdx][b].getDocCount();
+            }
+        }
+
+        buildSubAggsForAllBuckets(topBucketsPerOrd, b -> b.bucketOrd, (b, aggs) -> b.aggregations = aggs);
+
+        InternalAggregation[] result = new InternalAggregation[owningBucketOrds.length];
+        for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
+            result[ordIdx] = buildResult(owningBucketOrds[ordIdx], otherDocCounts[ordIdx], topBucketsPerOrd[ordIdx]);
+        }
+        return result;
+    }
+
+    InternalMultiTerms buildResult(long owningBucketOrd, long otherDocCount, InternalMultiTerms.Bucket[] topBuckets) {
+        BucketOrder reduceOrder;
+        if (isKeyOrder(order) == false) {
+            reduceOrder = InternalOrder.key(true);
+            Arrays.sort(topBuckets, reduceOrder.comparator());
+        } else {
+            reduceOrder = order;
+        }
+        return new InternalMultiTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata(),
+            bucketCountThresholds.getShardSize(),
+            showTermDocCountError,
+            otherDocCount,
+            0,
+            formats,
+            List.of(topBuckets),
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    public InternalAggregation buildEmptyAggregation() {
+        return new InternalMultiTerms(
+            name,
+            order,
+            order,
+            metadata(),
+            bucketCountThresholds.getShardSize(),
+            showTermDocCountError,
+            0,
+            0,
+            formats,
+            Collections.emptyList(),
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    protected LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCollector sub) throws IOException {
+        MultiTermsValuesSourceCollector collector = multiTermsValue.getValues(ctx);
+        return new LeafBucketCollector() {
+            @Override
+            public void collect(int doc, long owningBucketOrd) throws IOException {
+                for (BytesRef compositeKey : collector.apply(doc)) {
+                    long bucketOrd = bucketOrds.add(owningBucketOrd, compositeKey);
+                    if (bucketOrd < 0) {
+                        bucketOrd = -1 - bucketOrd;
+                        collectExistingBucket(sub, doc, bucketOrd);
+                    } else {
+                        collectBucket(sub, doc, bucketOrd);
+                    }
+                }
+            }
+        };
+    }
+
+    @Override
+    protected void doClose() {
+        Releasables.close(bucketOrds, multiTermsValue);
+    }
+
+    private static List<Object> decode(BytesRef bytesRef) {
+        try (StreamInput input = new BytesArray(bytesRef).streamInput()) {
+            return input.readList(StreamInput::readGenericValue);
+        } catch (IOException e) {
+            throw ExceptionsHelper.convertToRuntime(e);
+        }
+    }
+
+    private boolean subAggsNeedScore() {
+        for (Aggregator subAgg : subAggregators) {
+            if (subAgg.scoreMode().needsScores()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    protected boolean shouldDefer(Aggregator aggregator) {
+        return collectMode == Aggregator.SubAggCollectionMode.BREADTH_FIRST && !aggsUsedForSorting.contains(aggregator);
+    }
+
+    private void collectZeroDocEntriesIfNeeded(long owningBucketOrd) throws IOException {
+        if (bucketCountThresholds.getMinDocCount() != 0) {
+            return;
+        }
+        if (InternalOrder.isCountDesc(order) && bucketOrds.bucketsInOrd(owningBucketOrd) >= bucketCountThresholds.getRequiredSize()) {
+            return;
+        }
+        // we need to fill-in the blanks
+        for (LeafReaderContext ctx : context.searcher().getTopReaderContext().leaves()) {
+            MultiTermsValuesSourceCollector collector = multiTermsValue.getValues(ctx);
+            // brute force
+            for (int docId = 0; docId < ctx.reader().maxDoc(); ++docId) {
+                for (BytesRef compositeKey : collector.apply(docId)) {
+                    bucketOrds.add(owningBucketOrd, compositeKey);
+                }
+            }
+        }
+    }
+
+    /**
+     * A multi_terms collector which collect values on each doc,
+     */
+    @FunctionalInterface
+    interface MultiTermsValuesSourceCollector {
+        /**
+         * Collect a list values of multi_terms on each doc.
+         * Each terms could have multi_values, so the result is the cartesian product of each term's values.
+         */
+        List<BytesRef> apply(int doc) throws IOException;
+    }
+
+    @FunctionalInterface
+    interface InternalValuesSource {
+        /**
+         * Create {@link InternalValuesSourceCollector} from existing {@link LeafReaderContext}.
+         */
+        InternalValuesSourceCollector apply(LeafReaderContext ctx) throws IOException;
+    }
+
+    /**
+     * A terms collector which collect values on each doc,
+     */
+    @FunctionalInterface
+    interface InternalValuesSourceCollector {
+        /**
+         * Collect a list values of a term on specific doc.
+         */
+        List<TermValue<?>> apply(int doc) throws IOException;
+    }
+
+    /**
+     * Represents an individual term value.
+     */
+    static class TermValue<T> implements Writeable {
+        private static final Writer<BytesRef> BYTES_REF_WRITER = StreamOutput.getWriter(BytesRef.class);
+        private static final Writer<Long> LONG_WRITER = StreamOutput.getWriter(Long.class);
+        private static final Writer<BigInteger> BIG_INTEGER_WRITER = StreamOutput.getWriter(BigInteger.class);
+        private static final Writer<Double> DOUBLE_WRITER = StreamOutput.getWriter(Double.class);
+
+        private final T value;
+        private final Writer<T> writer;
+
+        private TermValue(T value, Writer<T> writer) {
+            this.value = value;
+            this.writer = writer;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            writer.write(out, value);
+        }
+
+        public static TermValue<BytesRef> of(BytesRef value) {
+            return new TermValue<>(value, BYTES_REF_WRITER);
+        }
+
+        public static TermValue<Long> of(Long value) {
+            return new TermValue<>(value, LONG_WRITER);
+        }
+
+        public static TermValue<BigInteger> of(BigInteger value) {
+            return new TermValue<>(value, BIG_INTEGER_WRITER);
+        }
+
+        public static TermValue<Double> of(Double value) {
+            return new TermValue<>(value, DOUBLE_WRITER);
+        }
+    }
+
+    /**
+     * Multi_Term ValuesSource, it is a collection of {@link InternalValuesSource}
+     *
+     * @opensearch.internal
+     */
+    static class MultiTermsValuesSource implements Releasable {
+        private final List<InternalValuesSource> valuesSources;
+        private final BytesStreamOutput scratch = new BytesStreamOutput();
+
+        public MultiTermsValuesSource(List<InternalValuesSource> valuesSources) {
+            this.valuesSources = valuesSources;
+        }
+
+        public MultiTermsValuesSourceCollector getValues(LeafReaderContext ctx) throws IOException {
+            List<InternalValuesSourceCollector> collectors = new ArrayList<>();
+            for (InternalValuesSource valuesSource : valuesSources) {
+                collectors.add(valuesSource.apply(ctx));
+            }
+            return new MultiTermsValuesSourceCollector() {
+                @Override
+                public List<BytesRef> apply(int doc) throws IOException {
+                    List<List<TermValue<?>>> collectedValues = new ArrayList<>();
+                    for (InternalValuesSourceCollector collector : collectors) {
+                        collectedValues.add(collector.apply(doc));
+                    }
+                    List<BytesRef> result = new ArrayList<>();
+                    scratch.seek(0);
+                    scratch.writeVInt(collectors.size()); // number of fields per composite key
+                    cartesianProduct(result, scratch, collectedValues, 0);
+                    return result;
+                }
+
+                /**
+                 * Cartesian product using depth first search.
+                 *
+                 * <p>
+                 * Composite keys are encoded to a {@link BytesRef} in a format compatible with {@link StreamOutput::writeGenericValue},
+                 * but reuses the encoding of the shared prefixes from the previous levels to avoid wasteful work.
+                 */
+                private void cartesianProduct(
+                    List<BytesRef> compositeKeys,
+                    BytesStreamOutput scratch,
+                    List<List<TermValue<?>>> collectedValues,
+                    int index
+                ) throws IOException {
+                    if (collectedValues.size() == index) {
+                        compositeKeys.add(BytesRef.deepCopyOf(scratch.bytes().toBytesRef()));
+                        return;
+                    }
+
+                    long position = scratch.position();
+                    for (TermValue<?> value : collectedValues.get(index)) {
+                        value.writeTo(scratch); // encode the value
+                        cartesianProduct(compositeKeys, scratch, collectedValues, index + 1); // dfs
+                        scratch.seek(position); // backtrack
+                    }
+                }
+            };
+        }
+
+        @Override
+        public void close() {
+            scratch.close();
+        }
+    }
+
+    /**
+     * Factory for construct {@link InternalValuesSource}.
+     *
+     * @opensearch.internal
+     */
+    static class InternalValuesSourceFactory {
+        static InternalValuesSource bytesValuesSource(ValuesSource valuesSource, IncludeExclude.StringFilter includeExclude) {
+            return ctx -> {
+                SortedBinaryDocValues values = valuesSource.bytesValues(ctx);
+                return doc -> {
+                    if (false == values.advanceExact(doc)) {
+                        return Collections.emptyList();
+                    }
+                    int valuesCount = values.docValueCount();
+                    List<TermValue<?>> termValues = new ArrayList<>(valuesCount);
+
+                    // SortedBinaryDocValues don't guarantee uniqueness so we
+                    // need to take care of dups
+                    BytesRef previous = null;
+                    for (int i = 0; i < valuesCount; ++i) {
+                        BytesRef bytes = values.nextValue();
+                        if (includeExclude != null && false == includeExclude.accept(bytes)) {
+                            continue;
+                        }
+                        if (i > 0 && bytes.equals(previous)) {
+                            continue;
+                        }
+                        BytesRef copy = BytesRef.deepCopyOf(bytes);
+                        termValues.add(TermValue.of(copy));
+                        previous = copy;
+                    }
+                    return termValues;
+                };
+            };
+        }
+
+        static InternalValuesSource unsignedLongValuesSource(ValuesSource.Numeric valuesSource, IncludeExclude.LongFilter longFilter) {
+            return ctx -> {
+                SortedNumericDocValues values = valuesSource.longValues(ctx);
+                return doc -> {
+                    if (values.advanceExact(doc)) {
+                        int valuesCount = values.docValueCount();
+
+                        BigInteger previous = Numbers.MAX_UNSIGNED_LONG_VALUE;
+                        List<TermValue<?>> termValues = new ArrayList<>(valuesCount);
+                        for (int i = 0; i < valuesCount; ++i) {
+                            BigInteger val = Numbers.toUnsignedBigInteger(values.nextValue());
+                            if (previous.compareTo(val) != 0 || i == 0) {
+                                if (longFilter == null || longFilter.accept(NumericUtils.doubleToSortableLong(val.doubleValue()))) {
+                                    termValues.add(TermValue.of(val));
+                                }
+                                previous = val;
+                            }
+                        }
+                        return termValues;
+                    }
+                    return Collections.emptyList();
+                };
+            };
+        }
+
+        static InternalValuesSource longValuesSource(ValuesSource.Numeric valuesSource, IncludeExclude.LongFilter longFilter) {
+            return ctx -> {
+                SortedNumericDocValues values = valuesSource.longValues(ctx);
+                return doc -> {
+                    if (values.advanceExact(doc)) {
+                        int valuesCount = values.docValueCount();
+
+                        long previous = Long.MAX_VALUE;
+                        List<TermValue<?>> termValues = new ArrayList<>(valuesCount);
+                        for (int i = 0; i < valuesCount; ++i) {
+                            long val = values.nextValue();
+                            if (previous != val || i == 0) {
+                                if (longFilter == null || longFilter.accept(val)) {
+                                    termValues.add(TermValue.of(val));
+                                }
+                                previous = val;
+                            }
+                        }
+                        return termValues;
+                    }
+                    return Collections.emptyList();
+                };
+            };
+        }
+
+        static InternalValuesSource doubleValueSource(ValuesSource.Numeric valuesSource, IncludeExclude.LongFilter longFilter) {
+            return ctx -> {
+                SortedNumericDoubleValues values = valuesSource.doubleValues(ctx);
+                return doc -> {
+                    if (values.advanceExact(doc)) {
+                        int valuesCount = values.docValueCount();
+
+                        double previous = Double.MAX_VALUE;
+                        List<TermValue<?>> termValues = new ArrayList<>(valuesCount);
+                        for (int i = 0; i < valuesCount; ++i) {
+                            double val = values.nextValue();
+                            if (previous != val || i == 0) {
+                                if (longFilter == null || longFilter.accept(NumericUtils.doubleToSortableLong(val))) {
+                                    termValues.add(TermValue.of(val));
+                                }
+                                previous = val;
+                            }
+                        }
+                        return termValues;
+                    }
+                    return Collections.emptyList();
+                };
+            };
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregator.java
index 4ea341caa0fed..9d095bbf7dccf 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregator.java
@@ -37,7 +37,7 @@
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.util.NumericUtils;
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.collect.List;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.LongArray;
@@ -52,6 +52,7 @@
 import org.opensearch.search.aggregations.InternalOrder;
 import org.opensearch.search.aggregations.LeafBucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollectorBase;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude.LongFilter;
 import org.opensearch.search.aggregations.bucket.terms.LongKeyedBucketOrds.BucketOrdsEnum;
 import org.opensearch.search.aggregations.bucket.terms.SignificanceLookup.BackgroundFrequencyForLong;
@@ -61,7 +62,9 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Map;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
@@ -70,6 +73,11 @@
 import static java.util.Collections.emptyList;
 import static org.opensearch.search.aggregations.InternalOrder.isKeyOrder;
 
+/**
+ * Aggregate all docs that contain numeric terms
+ *
+ * @opensearch.internal
+ */
 public class NumericTermsAggregator extends TermsAggregator {
     private final ResultStrategy<?, ?> resultStrategy;
     private final ValuesSource.Numeric valuesSource;
@@ -166,13 +174,14 @@ abstract class ResultStrategy<R extends InternalAggregation, B extends InternalM
         implements
             Releasable {
         private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
+            LocalBucketCountThresholds localBucketCountThresholds = context.asLocalBucketCountThresholds(bucketCountThresholds);
             B[][] topBucketsPerOrd = buildTopBucketsPerOrd(owningBucketOrds.length);
             long[] otherDocCounts = new long[owningBucketOrds.length];
             for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
                 collectZeroDocEntriesIfNeeded(owningBucketOrds[ordIdx]);
                 long bucketsInOrd = bucketOrds.bucketsInOrd(owningBucketOrds[ordIdx]);
 
-                int size = (int) Math.min(bucketsInOrd, bucketCountThresholds.getShardSize());
+                int size = (int) Math.min(bucketsInOrd, localBucketCountThresholds.getRequiredSize());
                 PriorityQueue<B> ordered = buildPriorityQueue(size);
                 B spare = null;
                 BucketOrdsEnum ordsEnum = bucketOrds.ordsEnum(owningBucketOrds[ordIdx]);
@@ -180,7 +189,7 @@ private InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws
                 while (ordsEnum.next()) {
                     long docCount = bucketDocCount(ordsEnum.ord());
                     otherDocCounts[ordIdx] += docCount;
-                    if (docCount < bucketCountThresholds.getShardMinDocCount()) {
+                    if (docCount < localBucketCountThresholds.getMinDocCount()) {
                         continue;
                     }
                     if (spare == null) {
@@ -388,15 +397,14 @@ LongTerms buildResult(long owningBucketOrd, long otherDocCount, LongTerms.Bucket
                 name,
                 reduceOrder,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 otherDocCount,
                 List.of(topBuckets),
-                0
+                0,
+                bucketCountThresholds
             );
         }
 
@@ -406,15 +414,14 @@ LongTerms buildEmptyResult() {
                 name,
                 order,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 0,
                 emptyList(),
-                0
+                0,
+                bucketCountThresholds
             );
         }
     }
@@ -470,15 +477,14 @@ DoubleTerms buildResult(long owningBucketOrd, long otherDocCount, DoubleTerms.Bu
                 name,
                 reduceOrder,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 otherDocCount,
                 List.of(topBuckets),
-                0
+                0,
+                bucketCountThresholds
             );
         }
 
@@ -488,15 +494,93 @@ DoubleTerms buildEmptyResult() {
                 name,
                 order,
                 order,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 bucketCountThresholds.getShardSize(),
                 showTermDocCountError,
                 0,
                 emptyList(),
-                0
+                0,
+                bucketCountThresholds
+            );
+        }
+    }
+
+    class UnsignedLongTermsResults extends StandardTermsResultStrategy<UnsignedLongTerms, UnsignedLongTerms.Bucket> {
+        UnsignedLongTermsResults(boolean showTermDocCountError) {
+            super(showTermDocCountError);
+        }
+
+        @Override
+        String describe() {
+            return "unsigned_long_terms";
+        }
+
+        @Override
+        SortedNumericDocValues getValues(LeafReaderContext ctx) throws IOException {
+            return valuesSource.longValues(ctx);
+        }
+
+        @Override
+        UnsignedLongTerms.Bucket[][] buildTopBucketsPerOrd(int size) {
+            return new UnsignedLongTerms.Bucket[size][];
+        }
+
+        @Override
+        UnsignedLongTerms.Bucket[] buildBuckets(int size) {
+            return new UnsignedLongTerms.Bucket[size];
+        }
+
+        @Override
+        UnsignedLongTerms.Bucket buildEmptyBucket() {
+            return new UnsignedLongTerms.Bucket(BigInteger.ZERO, 0, null, showTermDocCountError, 0, format);
+        }
+
+        @Override
+        void updateBucket(UnsignedLongTerms.Bucket spare, BucketOrdsEnum ordsEnum, long docCount) {
+            spare.term = Numbers.toUnsignedBigInteger(ordsEnum.value());
+            spare.docCount = docCount;
+            spare.bucketOrd = ordsEnum.ord();
+        }
+
+        @Override
+        UnsignedLongTerms buildResult(long owningBucketOrd, long otherDocCount, UnsignedLongTerms.Bucket[] topBuckets) {
+            final BucketOrder reduceOrder;
+            if (isKeyOrder(order) == false) {
+                reduceOrder = InternalOrder.key(true);
+                Arrays.sort(topBuckets, reduceOrder.comparator());
+            } else {
+                reduceOrder = order;
+            }
+            return new UnsignedLongTerms(
+                name,
+                reduceOrder,
+                order,
+                metadata(),
+                format,
+                bucketCountThresholds.getShardSize(),
+                showTermDocCountError,
+                otherDocCount,
+                List.of(topBuckets),
+                0,
+                bucketCountThresholds
+            );
+        }
+
+        @Override
+        UnsignedLongTerms buildEmptyResult() {
+            return new UnsignedLongTerms(
+                name,
+                order,
+                order,
+                metadata(),
+                format,
+                bucketCountThresholds.getShardSize(),
+                showTermDocCountError,
+                0,
+                emptyList(),
+                0,
+                bucketCountThresholds
             );
         }
     }
@@ -582,17 +666,17 @@ void collectZeroDocEntriesIfNeeded(long owningBucketOrd) throws IOException {}
 
         @Override
         SignificantLongTerms buildResult(long owningBucketOrd, long otherDocCoun, SignificantLongTerms.Bucket[] topBuckets) {
-            return new SignificantLongTerms(
+            SignificantLongTerms significantLongTerms = new SignificantLongTerms(
                 name,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 subsetSizes.get(owningBucketOrd),
                 supersetSize,
                 significanceHeuristic,
-                List.of(topBuckets)
+                List.of(topBuckets),
+                bucketCountThresholds
             );
+            return significantLongTerms;
         }
 
         @Override
@@ -603,14 +687,13 @@ SignificantLongTerms buildEmptyResult() {
             int supersetSize = topReader.numDocs();
             return new SignificantLongTerms(
                 name,
-                bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(),
                 metadata(),
                 format,
                 0,
                 supersetSize,
                 significanceHeuristic,
-                emptyList()
+                emptyList(),
+                bucketCountThresholds
             );
         }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedDoubleTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedDoubleTerms.java
index 5be42312656f2..ea9942a3b7877 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedDoubleTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedDoubleTerms.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A double numeric terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedDoubleTerms extends ParsedTerms {
 
     @Override
@@ -60,6 +65,11 @@ public static ParsedDoubleTerms fromXContent(XContentParser parser, String name)
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for double terms
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedTerms.ParsedBucket {
 
         private Double key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongRareTerms.java
index e84c00519acd8..8566de9390825 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongRareTerms.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A long numeric term result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedLongRareTerms extends ParsedRareTerms {
     @Override
     public String getType() {
@@ -60,6 +65,11 @@ public static ParsedLongRareTerms fromXContent(XContentParser parser, String nam
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for rare long values
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedRareTerms.ParsedBucket {
 
         private Long key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongTerms.java
index f75d1695819a0..3e607ca8c6e85 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedLongTerms.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A long term agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedLongTerms extends ParsedTerms {
 
     @Override
@@ -60,6 +65,11 @@ public static ParsedLongTerms fromXContent(XContentParser parser, String name) t
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for long term values
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedTerms.ParsedBucket {
 
         private Long key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedMultiTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedMultiTerms.java
new file mode 100644
index 0000000000000..4254c35208cf5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedMultiTerms.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * A multi terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
+public class ParsedMultiTerms extends ParsedTerms {
+    @Override
+    public String getType() {
+        return MultiTermsAggregationBuilder.NAME;
+    }
+
+    private static final ObjectParser<ParsedMultiTerms, Void> PARSER = new ObjectParser<>(
+        ParsedMultiTerms.class.getSimpleName(),
+        true,
+        ParsedMultiTerms::new
+    );
+    static {
+        declareParsedTermsFields(PARSER, ParsedBucket::fromXContent);
+    }
+
+    public static ParsedMultiTerms fromXContent(XContentParser parser, String name) throws IOException {
+        ParsedMultiTerms aggregation = PARSER.parse(parser, null);
+        aggregation.setName(name);
+        return aggregation;
+    }
+
+    /**
+     * Parsed bucket for multi terms
+     *
+     * @opensearch.internal
+     */
+    public static class ParsedBucket extends ParsedTerms.ParsedBucket {
+
+        private List<Object> key;
+
+        @Override
+        public List<Object> getKey() {
+            return key;
+        }
+
+        @Override
+        public String getKeyAsString() {
+            String keyAsString = super.getKeyAsString();
+            if (keyAsString != null) {
+                return keyAsString;
+            }
+            if (key != null) {
+                return key.toString();
+            }
+            return null;
+        }
+
+        public Number getKeyAsNumber() {
+            throw new UnsupportedOperationException("not implemented");
+        }
+
+        @Override
+        protected XContentBuilder keyToXContent(XContentBuilder builder) throws IOException {
+            builder.field(CommonFields.KEY.getPreferredName(), key);
+            if (super.getKeyAsString() != null) {
+                builder.field(CommonFields.KEY_AS_STRING.getPreferredName(), getKeyAsString());
+            }
+            return builder;
+        }
+
+        static ParsedBucket fromXContent(XContentParser parser) throws IOException {
+            return parseTermsBucketXContent(parser, ParsedBucket::new, (p, bucket) -> { bucket.key = p.list(); });
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedRareTerms.java
index a9fcd6e0277e6..83702b2856b9a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedRareTerms.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -47,6 +47,11 @@
 import java.util.List;
 import java.util.function.Supplier;
 
+/**
+ * A rare term result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedRareTerms extends ParsedMultiBucketAggregation<ParsedRareTerms.ParsedBucket> implements RareTerms {
     @Override
     public List<? extends RareTerms.Bucket> getBuckets() {
@@ -80,6 +85,11 @@ static void declareParsedTermsFields(
         declareMultiBucketAggregationFields(objectParser, bucketParser::apply, bucketParser::apply);
     }
 
+    /**
+     * Parsed Bucket for rare term values
+     *
+     * @opensearch.internal
+     */
     public abstract static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements RareTerms.Bucket {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantLongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantLongTerms.java
index 1488588a6847a..c2f1e4759f57a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantLongTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantLongTerms.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A significant long terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedSignificantLongTerms extends ParsedSignificantTerms {
 
     @Override
@@ -58,6 +63,11 @@ public static ParsedSignificantLongTerms fromXContent(XContentParser parser, Str
         return parseSignificantTermsXContent(() -> PARSER.parse(parser, null), name);
     }
 
+    /**
+     * Parsed bucket for significant long values
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedSignificantTerms.ParsedBucket {
 
         private Long key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantStringTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantStringTerms.java
index 961e4881f1eb8..588e71a3d013a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantStringTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantStringTerms.java
@@ -33,13 +33,18 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.nio.CharBuffer;
 
+/**
+ * A significant string terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedSignificantStringTerms extends ParsedSignificantTerms {
 
     @Override
@@ -60,6 +65,11 @@ public static ParsedSignificantStringTerms fromXContent(XContentParser parser, S
         return parseSignificantTermsXContent(() -> PARSER.parse(parser, null), name);
     }
 
+    /**
+     * Parsed bucket for significant string values
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedSignificantTerms.ParsedBucket {
 
         private BytesRef key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantTerms.java
index b57635a50d2d9..2f69b20c6b911 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedSignificantTerms.java
@@ -35,11 +35,11 @@
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -52,6 +52,11 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * A significant terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedSignificantTerms extends ParsedMultiBucketAggregation<ParsedSignificantTerms.ParsedBucket>
     implements
         SignificantTerms {
@@ -123,6 +128,11 @@ static void declareParsedSignificantTermsFields(
         );
     }
 
+    /**
+     * Parsed bucket for significant values
+     *
+     * @opensearch.internal
+     */
     public abstract static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements SignificantTerms.Bucket {
 
         protected long subsetDf;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringRareTerms.java
index 65a3090bee827..c606f48953567 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringRareTerms.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
 import java.io.IOException;
 import java.nio.CharBuffer;
 
-import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-
+/**
+ * A significant rare  result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedStringRareTerms extends ParsedRareTerms {
     @Override
     public String getType() {
@@ -62,6 +67,11 @@ public static ParsedStringRareTerms fromXContent(XContentParser parser, String n
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for rare string terms
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedRareTerms.ParsedBucket {
 
         private BytesRef key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringTerms.java
index faf34c6da5fec..ce297acded3a5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedStringTerms.java
@@ -33,13 +33,18 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.nio.CharBuffer;
 
+/**
+ * A string result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedStringTerms extends ParsedTerms {
 
     @Override
@@ -62,6 +67,11 @@ public static ParsedStringTerms fromXContent(XContentParser parser, String name)
         return aggregation;
     }
 
+    /**
+     * Parsed bucket for string values
+     *
+     * @opensearch.internal
+     */
     public static class ParsedBucket extends ParsedTerms.ParsedBucket {
 
         private BytesRef key;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedTerms.java
index ce5f56c898fa6..33d9c6cfaf4b9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedTerms.java
@@ -34,10 +34,10 @@
 
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
@@ -50,6 +50,11 @@
 import static org.opensearch.search.aggregations.bucket.terms.InternalTerms.DOC_COUNT_ERROR_UPPER_BOUND_FIELD_NAME;
 import static org.opensearch.search.aggregations.bucket.terms.InternalTerms.SUM_OF_OTHER_DOC_COUNTS;
 
+/**
+ * A terms result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedTerms extends ParsedMultiBucketAggregation<ParsedTerms.ParsedBucket> implements Terms {
 
     protected long docCountErrorUpperBound;
@@ -104,6 +109,11 @@ static void declareParsedTermsFields(
         objectParser.declareLong((parsedTerms, value) -> parsedTerms.sumOtherDocCount = value, SUM_OF_OTHER_DOC_COUNTS);
     }
 
+    /**
+     * Base parsed bucket
+     *
+     * @opensearch.internal
+     */
     public abstract static class ParsedBucket extends ParsedMultiBucketAggregation.ParsedBucket implements Terms.Bucket {
 
         boolean showDocCountError = false;
@@ -139,13 +149,16 @@ static <B extends ParsedBucket> B parseTermsBucketXContent(
             XContentParser.Token token;
             String currentFieldName = parser.currentName();
             while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                // field value could be list, e.g. multi_terms aggregation.
+                if ((token.isValue() || token == XContentParser.Token.START_ARRAY)
+                    && CommonFields.KEY.getPreferredName().equals(currentFieldName)) {
+                    keyConsumer.accept(parser, bucket);
+                }
                 if (token == XContentParser.Token.FIELD_NAME) {
                     currentFieldName = parser.currentName();
                 } else if (token.isValue()) {
                     if (CommonFields.KEY_AS_STRING.getPreferredName().equals(currentFieldName)) {
                         bucket.setKeyAsString(parser.text());
-                    } else if (CommonFields.KEY.getPreferredName().equals(currentFieldName)) {
-                        keyConsumer.accept(parser, bucket);
                     } else if (CommonFields.DOC_COUNT.getPreferredName().equals(currentFieldName)) {
                         bucket.setDocCount(parser.longValue());
                     } else if (DOC_COUNT_ERROR_UPPER_BOUND_FIELD_NAME.getPreferredName().equals(currentFieldName)) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedUnsignedLongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedUnsignedLongTerms.java
new file mode 100644
index 0000000000000..e6b0e14c7a384
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/ParsedUnsignedLongTerms.java
@@ -0,0 +1,88 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.math.BigInteger;
+
+/**
+ * A long term agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
+public class ParsedUnsignedLongTerms extends ParsedTerms {
+
+    @Override
+    public String getType() {
+        return UnsignedLongTerms.NAME;
+    }
+
+    private static final ObjectParser<ParsedUnsignedLongTerms, Void> PARSER = new ObjectParser<>(
+        ParsedUnsignedLongTerms.class.getSimpleName(),
+        true,
+        ParsedUnsignedLongTerms::new
+    );
+    static {
+        declareParsedTermsFields(PARSER, ParsedBucket::fromXContent);
+    }
+
+    public static ParsedUnsignedLongTerms fromXContent(XContentParser parser, String name) throws IOException {
+        ParsedUnsignedLongTerms aggregation = PARSER.parse(parser, null);
+        aggregation.setName(name);
+        return aggregation;
+    }
+
+    /**
+     * Parsed bucket for long term values
+     *
+     * @opensearch.internal
+     */
+    public static class ParsedBucket extends ParsedTerms.ParsedBucket {
+
+        private BigInteger key;
+
+        @Override
+        public Object getKey() {
+            return key;
+        }
+
+        @Override
+        public String getKeyAsString() {
+            String keyAsString = super.getKeyAsString();
+            if (keyAsString != null) {
+                return keyAsString;
+            }
+            if (key != null) {
+                return key.toString();
+            }
+            return null;
+        }
+
+        public Number getKeyAsNumber() {
+            return key;
+        }
+
+        @Override
+        protected XContentBuilder keyToXContent(XContentBuilder builder) throws IOException {
+            builder.field(CommonFields.KEY.getPreferredName(), key);
+            if (super.getKeyAsString() != null) {
+                builder.field(CommonFields.KEY_AS_STRING.getPreferredName(), getKeyAsString());
+            }
+            return builder;
+        }
+
+        static ParsedBucket fromXContent(XContentParser parser) throws IOException {
+            return parseTermsBucketXContent(parser, ParsedBucket::new, (p, bucket) -> bucket.key = p.bigIntegerValue());
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTerms.java
index 4e9c9be2cd255..f930e199e8f1b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTerms.java
@@ -35,10 +35,17 @@
 
 import java.util.List;
 
+/**
+ * Rare terms interface
+ *
+ * @opensearch.internal
+ */
 public interface RareTerms extends MultiBucketsAggregation {
 
     /**
      * A bucket that is associated with a single term
+     *
+     * @opensearch.internal
      */
     interface Bucket extends MultiBucketsAggregation.Bucket {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregationBuilder.java
index 2b419d1a45219..dc616ca7512be 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregationBuilder.java
@@ -32,11 +32,11 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -52,6 +52,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for rare_terms agg
+ *
+ * @opensearch.internal
+ */
 public class RareTermsAggregationBuilder extends ValuesSourceAggregationBuilder<RareTermsAggregationBuilder> {
     public static final String NAME = "rare_terms";
     public static final ValuesSourceRegistry.RegistryKey<RareTermsAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorFactory.java
index 0e03f87b070e1..b5f3abe89ac59 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorFactory.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
@@ -53,6 +53,11 @@
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for rare_terms agg
+ *
+ * @opensearch.internal
+ */
 public class RareTermsAggregatorFactory extends ValuesSourceAggregatorFactory {
     private final IncludeExclude includeExclude;
     private final int maxDocCount;
@@ -232,6 +237,16 @@ protected Aggregator doCreateInternal(
             );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
+    /**
+     * Execution mode for rare terms agg
+     *
+     * @opensearch.internal
+     */
     public enum ExecutionMode {
 
         MAP(new ParseField("map")) {
@@ -250,7 +265,10 @@ Aggregator create(
                 double precision,
                 CardinalityUpperBound cardinality
             ) throws IOException {
-                final IncludeExclude.StringFilter filter = includeExclude == null ? null : includeExclude.convertToStringFilter(format);
+                int maxRegexLength = context.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+                final IncludeExclude.StringFilter filter = includeExclude == null
+                    ? null
+                    : includeExclude.convertToStringFilter(format, maxRegexLength);
                 return new StringRareTermsAggregator(
                     name,
                     factories,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorSupplier.java
index 7fe05adc7c610..5f8888e2819c2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorSupplier.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for rare_terms agg
+ *
+ * @opensearch.internal
+ */
 interface RareTermsAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificanceLookup.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificanceLookup.java
index 3911352568356..34bbac55900a8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificanceLookup.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificanceLookup.java
@@ -60,6 +60,8 @@
 
 /**
  * Looks up values used for {@link SignificanceHeuristic}s.
+ *
+ * @opensearch.internal
  */
 class SignificanceLookup {
     /**
@@ -121,7 +123,7 @@ public void close() {}
             };
         }
         return new BackgroundFrequencyForBytes() {
-            private final BytesRefHash termToPosition = new BytesRefHash(1, bigArrays);
+            private final BytesRefHash termToPosition = new BytesRefHash(bigArrays);
             private LongArray positionToFreq = bigArrays.newLongArray(1, false);
 
             @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTerms.java
index 1aebdc663737e..3da5a766fc37b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTerms.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
@@ -45,10 +45,17 @@
 
 /**
  * Result of the running the significant terms aggregation on a numeric field.
+ *
+ * @opensearch.internal
  */
 public class SignificantLongTerms extends InternalMappedSignificantTerms<SignificantLongTerms, SignificantLongTerms.Bucket> {
     public static final String NAME = "siglterms";
 
+    /**
+     * Bucket for significant long values
+     *
+     * @opensearch.internal
+     */
     static class Bucket extends InternalSignificantTerms.Bucket<Bucket> {
 
         long term;
@@ -123,16 +130,15 @@ public int hashCode() {
 
     public SignificantLongTerms(
         String name,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         long subsetSize,
         long supersetSize,
         SignificanceHeuristic significanceHeuristic,
-        List<Bucket> buckets
+        List<Bucket> buckets,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
-        super(name, requiredSize, minDocCount, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets);
+        super(name, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets, bucketCountThresholds);
     }
 
     /**
@@ -151,14 +157,13 @@ public String getWriteableName() {
     public SignificantLongTerms create(List<SignificantLongTerms.Bucket> buckets) {
         return new SignificantLongTerms(
             name,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            buckets
+            buckets,
+            bucketCountThresholds
         );
     }
 
@@ -180,14 +185,13 @@ public Bucket createBucket(InternalAggregations aggregations, SignificantLongTer
     protected SignificantLongTerms create(long subsetSize, long supersetSize, List<Bucket> buckets) {
         return new SignificantLongTerms(
             getName(),
-            requiredSize,
-            minDocCount,
             getMetadata(),
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            buckets
+            buckets,
+            bucketCountThresholds
         );
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTerms.java
index 9c0f075ea5b22..c70db6005d7cd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTerms.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
@@ -46,10 +46,17 @@
 
 /**
  * Result of the running the significant terms aggregation on a String field.
+ *
+ * @opensearch.internal
  */
 public class SignificantStringTerms extends InternalMappedSignificantTerms<SignificantStringTerms, SignificantStringTerms.Bucket> {
     public static final String NAME = "sigsterms";
 
+    /**
+     * Bucket for significant string values
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalSignificantTerms.Bucket<Bucket> {
 
         BytesRef termBytes;
@@ -128,16 +135,15 @@ public int hashCode() {
 
     public SignificantStringTerms(
         String name,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         long subsetSize,
         long supersetSize,
         SignificanceHeuristic significanceHeuristic,
-        List<Bucket> buckets
+        List<Bucket> buckets,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
-        super(name, requiredSize, minDocCount, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets);
+        super(name, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets, bucketCountThresholds);
     }
 
     /**
@@ -156,14 +162,13 @@ public String getWriteableName() {
     public SignificantStringTerms create(List<SignificantStringTerms.Bucket> buckets) {
         return new SignificantStringTerms(
             name,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            buckets
+            buckets,
+            bucketCountThresholds
         );
     }
 
@@ -185,14 +190,13 @@ public Bucket createBucket(InternalAggregations aggregations, SignificantStringT
     protected SignificantStringTerms create(long subsetSize, long supersetSize, List<Bucket> buckets) {
         return new SignificantStringTerms(
             getName(),
-            requiredSize,
-            minDocCount,
             getMetadata(),
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            buckets
+            buckets,
+            bucketCountThresholds
         );
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTerms.java
index 299a6d29f1b85..e2eeac18575b0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTerms.java
@@ -37,9 +37,16 @@
 
 /**
  * An aggregation that collects significant terms in comparison to a background set.
+ *
+ * @opensearch.internal
  */
 public interface SignificantTerms extends MultiBucketsAggregation, Iterable<SignificantTerms.Bucket> {
 
+    /**
+     * Bucket for significant terms
+     *
+     * @opensearch.internal
+     */
     interface Bucket extends MultiBucketsAggregation.Bucket {
 
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregationBuilder.java
index 3c9c5797fff7a..00d5cb0a83c55 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregationBuilder.java
@@ -32,12 +32,12 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -60,6 +60,11 @@
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * Aggregation Builder for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class SignificantTermsAggregationBuilder extends ValuesSourceAggregationBuilder<SignificantTermsAggregationBuilder> {
     public static final String NAME = "significant_terms";
     public static final ValuesSourceRegistry.RegistryKey<SignificantTermsAggregatorSupplier> REGISTRY_KEY =
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorFactory.java
index db6106d3ce9bc..f6802a58dfed2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorFactory.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
@@ -58,6 +58,11 @@
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for significant_terms agg
+ *
+ * @opensearch.internal
+ */
 public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFactory {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(SignificantTermsAggregatorFactory.class);
 
@@ -241,12 +246,7 @@ public Aggregator build(
 
     @Override
     protected Aggregator createUnmapped(SearchContext searchContext, Aggregator parent, Map<String, Object> metadata) throws IOException {
-        final InternalAggregation aggregation = new UnmappedSignificantTerms(
-            name,
-            bucketCountThresholds.getRequiredSize(),
-            bucketCountThresholds.getMinDocCount(),
-            metadata
-        );
+        final InternalAggregation aggregation = new UnmappedSignificantTerms(name, bucketCountThresholds, metadata);
         return new NonCollectingAggregator(name, searchContext, parent, factories, metadata) {
             @Override
             public InternalAggregation buildEmptyAggregation() {
@@ -306,6 +306,16 @@ protected Aggregator doCreateInternal(
         );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
+    /**
+     * The execution mode for the significant terms agg
+     *
+     * @opensearch.internal
+     */
     public enum ExecutionMode {
 
         MAP(new ParseField("map")) {
@@ -325,8 +335,10 @@ Aggregator create(
                 CardinalityUpperBound cardinality,
                 Map<String, Object> metadata
             ) throws IOException {
-
-                final IncludeExclude.StringFilter filter = includeExclude == null ? null : includeExclude.convertToStringFilter(format);
+                int maxRegexLength = aggregationContext.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+                final IncludeExclude.StringFilter filter = includeExclude == null
+                    ? null
+                    : includeExclude.convertToStringFilter(format, maxRegexLength);
                 return new MapStringTermsAggregator(
                     name,
                     factories,
@@ -364,8 +376,10 @@ Aggregator create(
                 CardinalityUpperBound cardinality,
                 Map<String, Object> metadata
             ) throws IOException {
-
-                final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter(format);
+                int maxRegexLength = aggregationContext.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+                final IncludeExclude.OrdinalsFilter filter = includeExclude == null
+                    ? null
+                    : includeExclude.convertToOrdinalsFilter(format, maxRegexLength);
                 boolean remapGlobalOrd = true;
                 if (cardinality == CardinalityUpperBound.ONE && factories == AggregatorFactories.EMPTY && includeExclude == null) {
                     /*
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorSupplier.java
index 2d07527d61ede..a1fa7ab9d061e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorSupplier.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for significant_terms agg
+ *
+ * @opensearch.internal
+ */
 interface SignificantTermsAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregationBuilder.java
index bdfcf0e27fa58..b34c54ab54618 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
@@ -55,6 +55,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for significant text agg
+ *
+ * @opensearch.internal
+ */
 public class SignificantTextAggregationBuilder extends AbstractAggregationBuilder<SignificantTextAggregationBuilder> {
     public static final String NAME = "significant_text";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorFactory.java
index 85b4282e4c55b..81366c212c86c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorFactory.java
@@ -68,6 +68,11 @@
 import java.util.Map;
 import java.util.function.LongConsumer;
 
+/**
+ * Aggregation Factory for significant_text agg
+ *
+ * @opensearch.internal
+ */
 public class SignificantTextAggregatorFactory extends AggregatorFactory {
     private static final int MEMORY_GROWTH_REPORTING_INTERVAL_BYTES = 5000;
 
@@ -137,10 +142,12 @@ protected Aggregator createInternal(
 
         // TODO - need to check with mapping that this is indeed a text field....
 
-        IncludeExclude.StringFilter incExcFilter = includeExclude == null ? null : includeExclude.convertToStringFilter(DocValueFormat.RAW);
+        int maxRegexLength = searchContext.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+        IncludeExclude.StringFilter incExcFilter = includeExclude == null
+            ? null
+            : includeExclude.convertToStringFilter(DocValueFormat.RAW, maxRegexLength);
 
         MapStringTermsAggregator.CollectorSource collectorSource = new SignificantTextCollectorSource(
-            queryShardContext.lookup().source(),
             queryShardContext.bigArrays(),
             fieldType,
             sourceFieldNames,
@@ -165,6 +172,11 @@ protected Aggregator createInternal(
         );
     }
 
+    /**
+     * Collects significant text
+     *
+     * @opensearch.internal
+     */
     private static class SignificantTextCollectorSource implements MapStringTermsAggregator.CollectorSource {
         private final SourceLookup sourceLookup;
         private final BigArrays bigArrays;
@@ -173,13 +185,14 @@ private static class SignificantTextCollectorSource implements MapStringTermsAgg
         private ObjectArray<DuplicateByteSequenceSpotter> dupSequenceSpotters;
 
         SignificantTextCollectorSource(
-            SourceLookup sourceLookup,
             BigArrays bigArrays,
             MappedFieldType fieldType,
             String[] sourceFieldNames,
             boolean filterDuplicateText
         ) {
-            this.sourceLookup = sourceLookup;
+            // Create a new SourceLookup instance per aggregator instead of use the shared one from SearchLookup. This is fine because it
+            // will only be accessed by this Aggregator instance and not anywhere else.
+            this.sourceLookup = new SourceLookup();
             this.bigArrays = bigArrays;
             this.fieldType = fieldType;
             this.sourceFieldNames = sourceFieldNames;
@@ -299,4 +312,9 @@ public void close() {
             Releasables.close(dupSequenceSpotters);
         }
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTerms.java
index 58473c715563c..e86f938ff2081 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTerms.java
@@ -32,10 +32,10 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.SetBackedScalingCuckooFilter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -45,9 +45,19 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of string rare terms
+ *
+ * @opensearch.internal
+ */
 public class StringRareTerms extends InternalMappedRareTerms<StringRareTerms, StringRareTerms.Bucket> {
     public static final String NAME = "srareterms";
 
+    /**
+     * Bucket for rare string terms
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalRareTerms.Bucket<Bucket> {
         BytesRef termBytes;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTermsAggregator.java
index b4093a73f7305..cc35fe75e5e92 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringRareTermsAggregator.java
@@ -58,6 +58,8 @@
 
 /**
  * An aggregator that finds "rare" string values (e.g. terms agg that orders ascending)
+ *
+ * @opensearch.internal
  */
 public class StringRareTermsAggregator extends AbstractRareTermsAggregator {
     private final ValuesSource.Bytes valuesSource;
@@ -133,7 +135,7 @@ public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws I
         Arrays.fill(mergeMap, -1);
         long offset = 0;
         for (int owningOrdIdx = 0; owningOrdIdx < owningBucketOrds.length; owningOrdIdx++) {
-            try (BytesRefHash bucketsInThisOwningBucketToCollect = new BytesRefHash(1, context.bigArrays())) {
+            try (BytesRefHash bucketsInThisOwningBucketToCollect = new BytesRefHash(context.bigArrays())) {
                 filters[owningOrdIdx] = newFilter();
                 List<StringRareTerms.Bucket> builtBuckets = new ArrayList<>();
                 BytesKeyedBucketOrds.BucketOrdsEnum collectedBuckets = bucketOrds.ordsEnum(owningBucketOrds[owningOrdIdx]);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringTerms.java
index 3e70428472c37..6dedc65ff14e3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/StringTerms.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -46,10 +46,17 @@
 
 /**
  * Result of the {@link TermsAggregator} when the field is a String.
+ *
+ * @opensearch.internal
  */
 public class StringTerms extends InternalMappedTerms<StringTerms, StringTerms.Bucket> {
     public static final String NAME = "sterms";
 
+    /**
+     * Bucket for string terms
+     *
+     * @opensearch.internal
+     */
     public static class Bucket extends InternalTerms.Bucket<Bucket> {
         BytesRef termBytes;
 
@@ -127,29 +134,27 @@ public StringTerms(
         String name,
         BucketOrder reduceOrder,
         BucketOrder order,
-        int requiredSize,
-        long minDocCount,
         Map<String, Object> metadata,
         DocValueFormat format,
         int shardSize,
         boolean showTermDocCountError,
         long otherDocCount,
         List<Bucket> buckets,
-        long docCountError
+        long docCountError,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
     ) {
         super(
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -171,15 +176,14 @@ public StringTerms create(List<Bucket> buckets) {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -206,15 +210,14 @@ protected StringTerms create(String name, List<Bucket> buckets, BucketOrder redu
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             getMetadata(),
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/Terms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/Terms.java
index e6cb64928c0d8..e2e07ffa6ae59 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/Terms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/Terms.java
@@ -38,11 +38,15 @@
 /**
  * A {@code terms} aggregation. Defines multiple bucket, each associated with a unique term for a specific field.
  * All documents in a bucket has the bucket's term in that field.
+ *
+ * @opensearch.internal
  */
 public interface Terms extends MultiBucketsAggregation {
 
     /**
      * A bucket that is associated with a single term
+     *
+     * @opensearch.internal
      */
     interface Bucket extends MultiBucketsAggregation.Bucket {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregationBuilder.java
index 11a51f51d53c1..390348a9fa7d1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregationBuilder.java
@@ -32,12 +32,12 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -60,6 +60,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for terms agg
+ *
+ * @opensearch.internal
+ */
 public class TermsAggregationBuilder extends ValuesSourceAggregationBuilder<TermsAggregationBuilder> {
     public static final String NAME = "terms";
     public static final ValuesSourceRegistry.RegistryKey<TermsAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregator.java
index a5ee44ffa222e..7cacf1e918380 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregator.java
@@ -33,12 +33,13 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -56,8 +57,18 @@
 import java.util.Objects;
 import java.util.Set;
 
+/**
+ * Base aggregator class to aggregate documents by terms
+ *
+ * @opensearch.internal
+ */
 public abstract class TermsAggregator extends DeferableBucketAggregator {
 
+    /**
+     * Bucket count thresholds
+     *
+     * @opensearch.internal
+     */
     public static class BucketCountThresholds implements Writeable, ToXContentFragment {
         private long minDocCount;
         private long shardMinDocCount;
@@ -185,6 +196,30 @@ public boolean equals(Object obj) {
         }
     }
 
+    /**
+     * BucketCountThresholds type that throws an exception when shardMinDocCount or shardSize are accessed. This is used for
+     * deserialization on the coordinator during reduce as shardMinDocCount and shardSize should not be accessed this way on the
+     * coordinator.
+     *
+     * @opensearch.internal
+     */
+    public static class CoordinatorBucketCountThresholds extends BucketCountThresholds {
+
+        public CoordinatorBucketCountThresholds(long minDocCount, long shardMinDocCount, int requiredSize, int shardSize) {
+            super(minDocCount, shardMinDocCount, requiredSize, shardSize);
+        }
+
+        @Override
+        public long getShardMinDocCount() {
+            throw new AggregationExecutionException("shard_min_doc_count should not be accessed via CoordinatorBucketCountThresholds");
+        }
+
+        @Override
+        public int getShardSize() {
+            throw new AggregationExecutionException("shard_size should not be accessed via CoordinatorBucketCountThresholds");
+        }
+    }
+
     protected final DocValueFormat format;
     protected final BucketCountThresholds bucketCountThresholds;
     protected final BucketOrder order;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorFactory.java
index d2272d0a63042..a4d73bfd3e634 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorFactory.java
@@ -33,7 +33,7 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.search.IndexSearcher;
-import org.opensearch.common.ParseField;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationExecutionException;
@@ -62,6 +62,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Aggregation Factory for terms agg
+ *
+ * @opensearch.internal
+ */
 public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory {
     static Boolean REMAP_GLOBAL_ORDS, COLLECT_SEGMENT_ORDS;
 
@@ -198,6 +203,11 @@ public Aggregator build(
                         longFilter = includeExclude.convertToDoubleFilter();
                     }
                     resultStrategy = agg -> agg.new DoubleTermsResults(showTermDocCountError);
+                } else if (numericValuesSource.isBigInteger()) {
+                    if (includeExclude != null) {
+                        longFilter = includeExclude.convertToDoubleFilter();
+                    }
+                    resultStrategy = agg -> agg.new UnsignedLongTermsResults(showTermDocCountError);
                 } else {
                     if (includeExclude != null) {
                         longFilter = includeExclude.convertToLongFilter(format);
@@ -255,13 +265,7 @@ public Aggregator build(
 
     @Override
     protected Aggregator createUnmapped(SearchContext searchContext, Aggregator parent, Map<String, Object> metadata) throws IOException {
-        final InternalAggregation aggregation = new UnmappedTerms(
-            name,
-            order,
-            bucketCountThresholds.getRequiredSize(),
-            bucketCountThresholds.getMinDocCount(),
-            metadata
-        );
+        final InternalAggregation aggregation = new UnmappedTerms(name, order, bucketCountThresholds, metadata);
         Aggregator agg = new NonCollectingAggregator(name, searchContext, parent, factories, metadata) {
             @Override
             public InternalAggregation buildEmptyAggregation() {
@@ -360,6 +364,11 @@ private static long getMaxOrd(ValuesSource source, IndexSearcher searcher) throw
         }
     }
 
+    /**
+     * The execution mode for the terms agg
+     *
+     * @opensearch.internal
+     */
     public enum ExecutionMode {
 
         MAP(new ParseField("map")) {
@@ -380,7 +389,10 @@ Aggregator create(
                 CardinalityUpperBound cardinality,
                 Map<String, Object> metadata
             ) throws IOException {
-                final IncludeExclude.StringFilter filter = includeExclude == null ? null : includeExclude.convertToStringFilter(format);
+                int maxRegexLength = context.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+                final IncludeExclude.StringFilter filter = includeExclude == null
+                    ? null
+                    : includeExclude.convertToStringFilter(format, maxRegexLength);
                 return new MapStringTermsAggregator(
                     name,
                     factories,
@@ -431,7 +443,7 @@ Aggregator create(
                     && ordinalsValuesSource.supportsGlobalOrdinalsMapping()
                     &&
                 // we use the static COLLECT_SEGMENT_ORDS to allow tests to force specific optimizations
-                (COLLECT_SEGMENT_ORDS != null ? COLLECT_SEGMENT_ORDS.booleanValue() : ratio <= 0.5 && maxOrd <= 2048)) {
+                    (COLLECT_SEGMENT_ORDS != null ? COLLECT_SEGMENT_ORDS.booleanValue() : ratio <= 0.5 && maxOrd <= 2048)) {
                     /*
                      * We can use the low cardinality execution mode iff this aggregator:
                      *  - has no sub-aggregator AND
@@ -458,7 +470,10 @@ Aggregator create(
                     );
 
                 }
-                final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter(format);
+                int maxRegexLength = context.getQueryShardContext().getIndexSettings().getMaxRegexLength();
+                final IncludeExclude.OrdinalsFilter filter = includeExclude == null
+                    ? null
+                    : includeExclude.convertToOrdinalsFilter(format, maxRegexLength);
                 boolean remapGlobalOrds;
                 if (cardinality == CardinalityUpperBound.ONE && REMAP_GLOBAL_ORDS != null) {
                     /*
@@ -543,4 +558,8 @@ public String toString() {
         }
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorSupplier.java
index a9b319378937d..ea1484c6b9eef 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorSupplier.java
@@ -34,14 +34,19 @@
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.AggregatorFactories;
-import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for terms agg
+ *
+ * @opensearch.internal
+ */
 interface TermsAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedRareTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedRareTerms.java
index ef759cf4e7475..f3010f87b430e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedRareTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedRareTerms.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.SetBackedScalingCuckooFilter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -48,10 +48,17 @@
 
 /**
  * Result of the RareTerms aggregation when the field is unmapped.
+ *
+ * @opensearch.internal
  */
 public class UnmappedRareTerms extends InternalRareTerms<UnmappedRareTerms, UnmappedRareTerms.Bucket> {
     public static final String NAME = "umrareterms";
 
+    /**
+     * Bucket for unmapped rare values
+     *
+     * @opensearch.internal
+     */
     protected abstract static class Bucket extends InternalRareTerms.Bucket<Bucket> {
         private Bucket(long docCount, InternalAggregations aggregations, DocValueFormat formatter) {
             super(docCount, aggregations, formatter);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedSignificantTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedSignificantTerms.java
index a99f013327a88..2c8aa8f0a0c37 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedSignificantTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedSignificantTerms.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.bucket.terms;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregations;
@@ -50,6 +50,8 @@
 
 /**
  * Result of the running the significant terms aggregation on an unmapped field.
+ *
+ * @opensearch.internal
  */
 public class UnmappedSignificantTerms extends InternalSignificantTerms<UnmappedSignificantTerms, UnmappedSignificantTerms.Bucket> {
 
@@ -58,6 +60,8 @@ public class UnmappedSignificantTerms extends InternalSignificantTerms<UnmappedS
     /**
      * Concrete type that can't be built because Java needs a concrete type so {@link InternalTerms.Bucket} can have a self type but
      * {@linkplain UnmappedTerms} doesn't ever need to build it because it never returns any buckets.
+     *
+     * @opensearch.internal
      */
     protected abstract static class Bucket extends InternalSignificantTerms.Bucket<Bucket> {
         private Bucket(
@@ -73,8 +77,12 @@ private Bucket(
         }
     }
 
-    public UnmappedSignificantTerms(String name, int requiredSize, long minDocCount, Map<String, Object> metadata) {
-        super(name, requiredSize, minDocCount, metadata);
+    public UnmappedSignificantTerms(
+        String name,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
+        Map<String, Object> metadata
+    ) {
+        super(name, bucketCountThresholds, metadata);
     }
 
     /**
@@ -101,7 +109,7 @@ public String getType() {
 
     @Override
     public UnmappedSignificantTerms create(List<Bucket> buckets) {
-        return new UnmappedSignificantTerms(name, requiredSize, minDocCount, metadata);
+        return new UnmappedSignificantTerms(name, bucketCountThresholds, metadata);
     }
 
     @Override
@@ -128,7 +136,7 @@ Bucket createBucket(
 
     @Override
     public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
-        return new UnmappedSignificantTerms(name, requiredSize, minDocCount, metadata);
+        return new UnmappedSignificantTerms(name, bucketCountThresholds, metadata);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedTerms.java
index ad499aed451d1..3d2bbb93c889a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedTerms.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnmappedTerms.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.bucket.terms;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.BucketOrder;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -48,6 +48,8 @@
 
 /**
  * Result of the {@link TermsAggregator} when the field is unmapped.
+ *
+ * @opensearch.internal
  */
 public class UnmappedTerms extends InternalTerms<UnmappedTerms, UnmappedTerms.Bucket> {
     public static final String NAME = "umterms";
@@ -55,6 +57,8 @@ public class UnmappedTerms extends InternalTerms<UnmappedTerms, UnmappedTerms.Bu
     /**
      * Concrete type that can't be built because Java needs a concrete type so {@link InternalTerms.Bucket} can have a self type but
      * {@linkplain UnmappedTerms} doesn't ever need to build it because it never returns any buckets.
+     *
+     * @opensearch.internal
      */
     protected abstract static class Bucket extends InternalTerms.Bucket<Bucket> {
         private Bucket(
@@ -68,8 +72,13 @@ private Bucket(
         }
     }
 
-    public UnmappedTerms(String name, BucketOrder order, int requiredSize, long minDocCount, Map<String, Object> metadata) {
-        super(name, order, order, requiredSize, minDocCount, metadata);
+    public UnmappedTerms(
+        String name,
+        BucketOrder order,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds,
+        Map<String, Object> metadata
+    ) {
+        super(name, order, order, bucketCountThresholds, metadata);
     }
 
     /**
@@ -96,7 +105,7 @@ public String getType() {
 
     @Override
     public UnmappedTerms create(List<Bucket> buckets) {
-        return new UnmappedTerms(name, order, requiredSize, minDocCount, metadata);
+        return new UnmappedTerms(name, order, bucketCountThresholds, metadata);
     }
 
     @Override
@@ -116,7 +125,7 @@ protected UnmappedTerms create(String name, List<Bucket> buckets, BucketOrder re
 
     @Override
     public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
-        return new UnmappedTerms(name, order, requiredSize, minDocCount, metadata);
+        return new UnmappedTerms(name, order, bucketCountThresholds, metadata);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTerms.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTerms.java
new file mode 100644
index 0000000000000..edeec00d366fd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTerms.java
@@ -0,0 +1,281 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.InternalAggregations;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Result of the {@link TermsAggregator} when the field is some kind of whole number like a integer,
+ * long, unsigned long or a date.
+ *
+ * @opensearch.internal
+ */
+public class UnsignedLongTerms extends InternalMappedTerms<UnsignedLongTerms, UnsignedLongTerms.Bucket> {
+    public static final String NAME = "ulterms";
+
+    /**
+     * Bucket for long terms
+     *
+     * @opensearch.internal
+     */
+    public static class Bucket extends InternalTerms.Bucket<Bucket> {
+        BigInteger term;
+
+        public Bucket(
+            BigInteger term,
+            long docCount,
+            InternalAggregations aggregations,
+            boolean showDocCountError,
+            long docCountError,
+            DocValueFormat format
+        ) {
+            super(docCount, aggregations, showDocCountError, docCountError, format);
+            this.term = term;
+        }
+
+        /**
+         * Read from a stream.
+         */
+        public Bucket(StreamInput in, DocValueFormat format, boolean showDocCountError) throws IOException {
+            super(in, format, showDocCountError);
+            term = in.readBigInteger();
+        }
+
+        @Override
+        protected void writeTermTo(StreamOutput out) throws IOException {
+            out.writeBigInteger(term);
+        }
+
+        @Override
+        public String getKeyAsString() {
+            return format.format(term).toString();
+        }
+
+        @Override
+        public Object getKey() {
+            if (format == DocValueFormat.UNSIGNED_LONG_SHIFTED) {
+                return format.format(term);
+            } else {
+                return term;
+            }
+        }
+
+        @Override
+        public Number getKeyAsNumber() {
+            if (format == DocValueFormat.UNSIGNED_LONG_SHIFTED) {
+                return (Number) format.format(term);
+            } else {
+                return term;
+            }
+        }
+
+        @Override
+        public int compareKey(Bucket other) {
+            return term.compareTo(other.term);
+        }
+
+        @Override
+        protected final XContentBuilder keyToXContent(XContentBuilder builder) throws IOException {
+            if (format == DocValueFormat.UNSIGNED_LONG_SHIFTED) {
+                builder.field(CommonFields.KEY.getPreferredName(), format.format(term));
+            } else {
+                builder.field(CommonFields.KEY.getPreferredName(), term);
+            }
+            if (format != DocValueFormat.RAW && format != DocValueFormat.UNSIGNED_LONG_SHIFTED && format != DocValueFormat.UNSIGNED_LONG) {
+                builder.field(CommonFields.KEY_AS_STRING.getPreferredName(), format.format(term).toString());
+            }
+            return builder;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            return super.equals(obj) && Objects.equals(term, ((Bucket) obj).term);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(super.hashCode(), term);
+        }
+    }
+
+    public UnsignedLongTerms(
+        String name,
+        BucketOrder reduceOrder,
+        BucketOrder order,
+        Map<String, Object> metadata,
+        DocValueFormat format,
+        int shardSize,
+        boolean showTermDocCountError,
+        long otherDocCount,
+        List<Bucket> buckets,
+        long docCountError,
+        TermsAggregator.BucketCountThresholds bucketCountThresholds
+    ) {
+        super(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            format,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            buckets,
+            docCountError,
+            bucketCountThresholds
+        );
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public UnsignedLongTerms(StreamInput in) throws IOException {
+        super(in, Bucket::new);
+    }
+
+    @Override
+    public String getWriteableName() {
+        return NAME;
+    }
+
+    @Override
+    public UnsignedLongTerms create(List<Bucket> buckets) {
+        return new UnsignedLongTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            format,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            buckets,
+            docCountError,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    public Bucket createBucket(InternalAggregations aggregations, Bucket prototype) {
+        return new Bucket(
+            prototype.term,
+            prototype.docCount,
+            aggregations,
+            prototype.showDocCountError,
+            prototype.docCountError,
+            prototype.format
+        );
+    }
+
+    @Override
+    protected UnsignedLongTerms create(String name, List<Bucket> buckets, BucketOrder reduceOrder, long docCountError, long otherDocCount) {
+        return new UnsignedLongTerms(
+            name,
+            reduceOrder,
+            order,
+            getMetadata(),
+            format,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            buckets,
+            docCountError,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    protected Bucket[] createBucketsArray(int size) {
+        return new Bucket[size];
+    }
+
+    @Override
+    public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
+        boolean unsignedLongFormat = false;
+        boolean rawFormat = false;
+        for (InternalAggregation agg : aggregations) {
+            if (agg instanceof DoubleTerms) {
+                return agg.reduce(aggregations, reduceContext);
+            }
+            if (agg instanceof UnsignedLongTerms) {
+                if (((UnsignedLongTerms) agg).format == DocValueFormat.RAW) {
+                    rawFormat = true;
+                } else if (((UnsignedLongTerms) agg).format == DocValueFormat.UNSIGNED_LONG_SHIFTED) {
+                    unsignedLongFormat = true;
+                } else if (((UnsignedLongTerms) agg).format == DocValueFormat.UNSIGNED_LONG) {
+                    unsignedLongFormat = true;
+                }
+            }
+        }
+        if (rawFormat && unsignedLongFormat) { // if we have mixed formats, convert results to double format
+            List<InternalAggregation> newAggs = new ArrayList<>(aggregations.size());
+            for (InternalAggregation agg : aggregations) {
+                if (agg instanceof UnsignedLongTerms) {
+                    DoubleTerms dTerms = UnsignedLongTerms.convertUnsignedLongTermsToDouble((UnsignedLongTerms) agg, format);
+                    newAggs.add(dTerms);
+                } else {
+                    newAggs.add(agg);
+                }
+            }
+            return newAggs.get(0).reduce(newAggs, reduceContext);
+        }
+        return super.reduce(aggregations, reduceContext);
+    }
+
+    @Override
+    Bucket createBucket(long docCount, InternalAggregations aggs, long docCountError, UnsignedLongTerms.Bucket prototype) {
+        return new Bucket(prototype.term, docCount, aggs, prototype.showDocCountError, docCountError, format);
+    }
+
+    /**
+     * Converts a {@link UnsignedLongTerms} into a {@link DoubleTerms}, returning the value of the specified long terms as doubles.
+     */
+    static DoubleTerms convertUnsignedLongTermsToDouble(UnsignedLongTerms unsignedLongTerms, DocValueFormat decimalFormat) {
+        List<UnsignedLongTerms.Bucket> buckets = unsignedLongTerms.getBuckets();
+        List<DoubleTerms.Bucket> newBuckets = new ArrayList<>();
+        for (Terms.Bucket bucket : buckets) {
+            newBuckets.add(
+                new DoubleTerms.Bucket(
+                    bucket.getKeyAsNumber().doubleValue(),
+                    bucket.getDocCount(),
+                    (InternalAggregations) bucket.getAggregations(),
+                    unsignedLongTerms.showTermDocCountError,
+                    unsignedLongTerms.showTermDocCountError ? bucket.getDocCountError() : 0,
+                    decimalFormat
+                )
+            );
+        }
+        return new DoubleTerms(
+            unsignedLongTerms.getName(),
+            unsignedLongTerms.reduceOrder,
+            unsignedLongTerms.order,
+            unsignedLongTerms.metadata,
+            unsignedLongTerms.format,
+            unsignedLongTerms.shardSize,
+            unsignedLongTerms.showTermDocCountError,
+            unsignedLongTerms.otherDocCount,
+            newBuckets,
+            unsignedLongTerms.docCountError,
+            unsignedLongTerms.bucketCountThresholds
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ChiSquare.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ChiSquare.java
index 3083fa2b86814..833c7328e14f4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ChiSquare.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ChiSquare.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * ChiSquare significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class ChiSquare extends NXYSignificanceHeuristic {
     public static final String NAME = "chi_square";
     public static final ConstructingObjectParser<ChiSquare, Void> PARSER = new ConstructingObjectParser<>(
@@ -103,6 +108,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder for a chi squared heuristic
+     *
+     * @opensearch.internal
+     */
     public static class ChiSquareBuilder extends NXYSignificanceHeuristic.NXYBuilder {
         public ChiSquareBuilder(boolean includeNegatives, boolean backgroundIsSuperset) {
             super(includeNegatives, backgroundIsSuperset);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/GND.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/GND.java
index 4e88ad992bde0..347013498b61f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/GND.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/GND.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * GND significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class GND extends NXYSignificanceHeuristic {
     public static final String NAME = "gnd";
     public static final ConstructingObjectParser<GND, Void> PARSER = new ConstructingObjectParser<>(NAME, args -> {
@@ -122,6 +127,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder for a GND heuristic
+     *
+     * @opensearch.internal
+     */
     public static class GNDBuilder extends NXYBuilder {
         public GNDBuilder(boolean backgroundIsSuperset) {
             super(true, backgroundIsSuperset);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/JLHScore.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/JLHScore.java
index b3cc463f71e1b..aee00a1e422c9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/JLHScore.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/JLHScore.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import java.io.IOException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import java.io.IOException;
 
+/**
+ * JLHScore heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class JLHScore extends SignificanceHeuristic {
     public static final String NAME = "jlh";
     public static final ObjectParser<JLHScore, Void> PARSER = new ObjectParser<>(NAME, JLHScore::new);
@@ -124,6 +129,11 @@ public int hashCode() {
         return getClass().hashCode();
     }
 
+    /**
+     * Builder for a JLH Score heuristic
+     *
+     * @opensearch.internal
+     */
     public static class JLHScoreBuilder implements SignificanceHeuristicBuilder {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/MutualInformation.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/MutualInformation.java
index 3114aa940f2ef..86caa6d3b5059 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/MutualInformation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/MutualInformation.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Mutual Information significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class MutualInformation extends NXYSignificanceHeuristic {
     public static final String NAME = "mutual_information";
     public static final ConstructingObjectParser<MutualInformation, Void> PARSER = new ConstructingObjectParser<>(
@@ -142,6 +147,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder for a Mutual Information heuristic
+     *
+     * @opensearch.internal
+     */
     public static class MutualInformationBuilder extends NXYBuilder {
         public MutualInformationBuilder(boolean includeNegatives, boolean backgroundIsSuperset) {
             super(includeNegatives, backgroundIsSuperset);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/NXYSignificanceHeuristic.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/NXYSignificanceHeuristic.java
index a194765209a40..a2e9262482880 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/NXYSignificanceHeuristic.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/NXYSignificanceHeuristic.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * NXY significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public abstract class NXYSignificanceHeuristic extends SignificanceHeuristic {
 
     protected static final ParseField BACKGROUND_IS_SUPERSET = new ParseField("background_is_superset");
@@ -101,6 +106,11 @@ public int hashCode() {
         return result;
     }
 
+    /**
+     * Frequencies for an NXY significance heuristic
+     *
+     * @opensearch.internal
+     */
     protected static class Frequencies {
         double N00, N01, N10, N11, N0_, N1_, N_0, N_1, N;
     }
@@ -189,6 +199,11 @@ protected static <T> Function<Object[], T> buildFromParsedArgs(BiFunction<Boolea
         };
     }
 
+    /**
+     * Builder for a NXY Significance heuristic
+     *
+     * @opensearch.internal
+     */
     protected abstract static class NXYBuilder implements SignificanceHeuristicBuilder {
         protected boolean includeNegatives = true;
         protected boolean backgroundIsSuperset = true;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/PercentageScore.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/PercentageScore.java
index fa80ba67a7b5a..52078e916ce07 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/PercentageScore.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/PercentageScore.java
@@ -33,15 +33,20 @@
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardException;
 
 import java.io.IOException;
 
+/**
+ * Percentage score significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class PercentageScore extends SignificanceHeuristic {
     public static final String NAME = "percentage";
     public static final ObjectParser<PercentageScore, Void> PARSER = new ObjectParser<>(NAME, PercentageScore::new);
@@ -104,6 +109,11 @@ public int hashCode() {
         return getClass().hashCode();
     }
 
+    /**
+     * Builder for a Percentage Score heuristic
+     *
+     * @opensearch.internal
+     */
     public static class PercentageScoreBuilder implements SignificanceHeuristicBuilder {
 
         @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ScriptHeuristic.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ScriptHeuristic.java
index eeebdabda45fb..33a09548edc83 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ScriptHeuristic.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/ScriptHeuristic.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.script.SignificantTermsHeuristicScoreScript;
@@ -46,8 +46,13 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Script significance heuristic for significant terms agg
+ *
+ * @opensearch.internal
+ */
 public class ScriptHeuristic extends SignificanceHeuristic {
     public static final String NAME = "script_heuristic";
     public static final ConstructingObjectParser<ScriptHeuristic, Void> PARSER = new ConstructingObjectParser<>(
@@ -60,8 +65,12 @@ public class ScriptHeuristic extends SignificanceHeuristic {
 
     private final Script script;
 
-    // This class holds an executable form of the script with private variables ready for execution
-    // on a single search thread.
+    /**
+     * This class holds an executable form of the script with private variables ready for execution
+     * on a single search thread.
+     *
+     * @opensearch.internal
+     */
     static class ExecutableScriptHeuristic extends ScriptHeuristic {
         private final LongAccessor subsetSizeHolder;
         private final LongAccessor supersetSizeHolder;
@@ -173,6 +182,11 @@ public boolean equals(Object obj) {
         return Objects.equals(script, other.script);
     }
 
+    /**
+     * Accesses long values
+     *
+     * @opensearch.internal
+     */
     public final class LongAccessor extends Number {
         public long value;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristic.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristic.java
index b63cc483e58aa..8b78c1c4ecb3b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristic.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristic.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentFragment;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTerms;
 
 /**
  * Heuristic for that {@link SignificantTerms} uses to pick out significant terms.
+ *
+ * @opensearch.internal
  */
 public abstract class SignificanceHeuristic implements NamedWriteable, ToXContentFragment {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristicBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristicBuilder.java
index b824652bdbe08..f3783f97a8d05 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristicBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/SignificanceHeuristicBuilder.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.search.aggregations.bucket.terms.heuristic;
 
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentFragment;
 
+/**
+ * Base builder class for significance heuristics
+ *
+ * @opensearch.internal
+ */
 public interface SignificanceHeuristicBuilder extends ToXContentFragment {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/package-info.java
new file mode 100644
index 0000000000000..2a9d4fe5de436
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/heuristic/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Heuristic package for the Terms Aggregations. */
+package org.opensearch.search.aggregations.bucket.terms.heuristic;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/package-info.java
new file mode 100644
index 0000000000000..808b7d065b01f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/bucket/terms/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Terms Aggregation package. */
+package org.opensearch.search.aggregations.bucket.terms;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractCardinalityAlgorithm.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractCardinalityAlgorithm.java
index 8851313f61e5a..a8a7b513d01e5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractCardinalityAlgorithm.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractCardinalityAlgorithm.java
@@ -34,6 +34,8 @@
 
 /**
  * Base class for cardinality related algorithms.
+ *
+ * @opensearch.internal
  */
 abstract class AbstractCardinalityAlgorithm {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHDRPercentilesAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHDRPercentilesAggregator.java
index abf63ee0b73e6..e2edfd32f7ff8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHDRPercentilesAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHDRPercentilesAggregator.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.ScoreMode;
 import org.opensearch.common.lease.Releasables;
@@ -50,6 +49,13 @@
 import java.io.IOException;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Base aggregator for HDR percentiles agg
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractHDRPercentilesAggregator extends NumericMetricsAggregator.MultiValue {
 
     private static int indexOfKey(double[] keys, double key) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLog.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLog.java
index 8008d70f664a6..6b998fc86361d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLog.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLog.java
@@ -38,6 +38,8 @@
  * https://docs.google.com/document/d/1gyjfMHy43U9OWBXxfaeG-3MjGzejW1dlpyMwEYAAWEI/view?fullscreen
  *
  * Trying to understand what this class does without having read the paper is considered adventurous.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractHyperLogLog extends AbstractCardinalityAlgorithm {
 
@@ -5950,7 +5952,11 @@ private long threshold() {
         return THRESHOLDS[p - 4];
     }
 
-    /** Iterator over a HyperLogLog register */
+    /**
+     * Iterator over a HyperLogLog register
+     *
+     * @opensearch.internal
+     */
     public interface RunLenIterator {
 
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLogPlusPlus.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLogPlusPlus.java
index 75d9dea7ef86a..4354a23b70f6b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLogPlusPlus.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractHyperLogLogPlusPlus.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -48,6 +48,8 @@
  * Base class for HLL++ algorithms.
  *
  * It contains methods for cloning and serializing the data structure.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractHyperLogLogPlusPlus extends AbstractCardinalityAlgorithm implements Releasable {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
index 0dc2803d5f6c3..6f50d791594ff 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalHDRPercentiles.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -47,6 +46,13 @@
 import java.util.Objects;
 import java.util.zip.DataFormatException;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Base implementation of HDR percentiles
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractInternalHDRPercentiles extends InternalNumericMetricsAggregation.MultiValue {
 
     protected final double[] keys;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
index 5ac87df3e139c..398d0054403ac 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractInternalTDigestPercentiles.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Base implementation of TDigest percentiles
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractInternalTDigestPercentiles extends InternalNumericMetricsAggregation.MultiValue {
 
     protected final double[] keys;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractLinearCounting.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractLinearCounting.java
index 71a97e1456fab..3f5f524c9c2f5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractLinearCounting.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractLinearCounting.java
@@ -42,6 +42,8 @@
  * Trying to understand what this class does without having read the paper is considered adventurous.
  *
  * The algorithm just keep a record of all distinct values provided encoded as an integer.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractLinearCounting extends AbstractCardinalityAlgorithm {
 
@@ -100,7 +102,11 @@ static int encodeHash(long hash, int p) {
         return (int) encoded;
     }
 
-    /** Iterator over the hash values */
+    /**
+     * Iterator over the hash values
+     *
+     * @opensearch.internal
+     */
     public interface HashesIterator {
 
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesAggregationBuilder.java
index ac0baf18dfb55..a143b6a69da58 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesAggregationBuilder.java
@@ -33,13 +33,13 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.support.ValuesSource;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
@@ -55,6 +55,8 @@
  * This provides a base class for aggregations that are building percentiles or percentiles-like functionality (e.g. percentile ranks).
  * It provides a set of common fields/functionality for setting the available algorithms (TDigest and HDRHistogram),
  * as well as algorithm-specific settings via a {@link PercentilesConfig} object
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractPercentilesAggregationBuilder<T extends AbstractPercentilesAggregationBuilder<T>> extends
     ValuesSourceAggregationBuilder.LeafOnly<ValuesSource, T> {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractTDigestPercentilesAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractTDigestPercentilesAggregator.java
index 80bfcb55f7391..8c79a80a26b9e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractTDigestPercentilesAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AbstractTDigestPercentilesAggregator.java
@@ -49,6 +49,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base aggregator for the TDigest agg
+ *
+ * @opensearch.internal
+ */
 abstract class AbstractTDigestPercentilesAggregator extends NumericMetricsAggregator.MultiValue {
 
     private static int indexOfKey(double[] keys, double key) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Avg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Avg.java
index 0c662423b2407..4deffd60f28d8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Avg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Avg.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes the average of the values in the current bucket.
+ *
+ * @opensearch.internal
  */
 public interface Avg extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregationBuilder.java
index 8fd3febc4d2a9..d66053d49b327 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for avg agg
+ *
+ * @opensearch.internal
+ */
 public class AvgAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource.Numeric, AvgAggregationBuilder> {
     public static final String NAME = "avg";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregator.java
index 24cebdf289790..e58466b56df2a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregator.java
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into an average
+ *
+ * @opensearch.internal
+ */
 class AvgAggregator extends NumericMetricsAggregator.SingleValue {
 
     final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregatorFactory.java
index 696d65ec9d8aa..0a09fae1eaebe 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/AvgAggregatorFactory.java
@@ -44,8 +44,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for avg agg
+ *
+ * @opensearch.internal
+ */
 class AvgAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     AvgAggregatorFactory(
@@ -62,7 +68,7 @@ class AvgAggregatorFactory extends ValuesSourceAggregatorFactory {
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             AvgAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             AvgAggregator::new,
             true
         );
@@ -84,4 +90,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(AvgAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Cardinality.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Cardinality.java
index 749c2554cf479..dab281aa7ec6f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Cardinality.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Cardinality.java
@@ -34,6 +34,8 @@
 
 /**
  * An aggregation that computes approximate numbers of unique terms.
+ *
+ * @opensearch.internal
  */
 public interface Cardinality extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregationBuilder.java
index 12771f06e3192..a7516a6fd6b24 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregationBuilder.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations.metrics;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -53,6 +53,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for cardinality agg
+ *
+ * @opensearch.internal
+ */
 public final class CardinalityAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<
     ValuesSource,
     CardinalityAggregationBuilder> {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregator.java
index 61cb08ba28ab0..99c4eaac4b777 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregator.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
@@ -46,6 +45,7 @@
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.BitArray;
+import org.opensearch.common.util.BitMixer;
 import org.opensearch.common.util.LongArray;
 import org.opensearch.common.util.ObjectArray;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
@@ -63,6 +63,8 @@
 
 /**
  * An aggregator that computes approximate counts of unique values.
+ *
+ * @opensearch.internal
  */
 public class CardinalityAggregator extends NumericMetricsAggregator.SingleValue {
 
@@ -109,7 +111,7 @@ private Collector pickCollector(LeafReaderContext ctx) throws IOException {
 
         if (valuesSource instanceof ValuesSource.Numeric) {
             ValuesSource.Numeric source = (ValuesSource.Numeric) valuesSource;
-            MurmurHash3Values hashValues = source.isFloatingPoint()
+            MurmurHash3Values hashValues = (source.isFloatingPoint() || source.isBigInteger())
                 ? MurmurHash3Values.hash(source.doubleValues(ctx))
                 : MurmurHash3Values.hash(source.longValues(ctx));
             numericCollectorsUsed++;
@@ -199,12 +201,22 @@ public void collectDebugInfo(BiConsumer<String, Object> add) {
         add.accept("string_hashing_collectors_used", stringHashingCollectorsUsed);
     }
 
+    /**
+     * Collector for the cardinality agg
+     *
+     * @opensearch.internal
+     */
     private abstract static class Collector extends LeafBucketCollector implements Releasable {
 
         public abstract void postCollect() throws IOException;
 
     }
 
+    /**
+     * Empty Collector for the Cardinality agg
+     *
+     * @opensearch.internal
+     */
     private static class EmptyCollector extends Collector {
 
         @Override
@@ -223,6 +235,11 @@ public void close() {
         }
     }
 
+    /**
+     * Direct Collector for the cardinality agg
+     *
+     * @opensearch.internal
+     */
     private static class DirectCollector extends Collector {
 
         private final MurmurHash3Values hashes;
@@ -255,6 +272,11 @@ public void close() {
 
     }
 
+    /**
+     * Ordinals Collector for the cardinality agg
+     *
+     * @opensearch.internal
+     */
     private static class OrdinalsCollector extends Collector {
 
         private static final long SHALLOW_FIXEDBITSET_SIZE = RamUsageEstimator.shallowSizeOfInstance(FixedBitSet.class);
@@ -343,6 +365,8 @@ public void close() {
 
     /**
      * Representation of a list of hash values. There might be dups and there is no guarantee on the order.
+     *
+     * @opensearch.internal
      */
     abstract static class MurmurHash3Values {
 
@@ -373,6 +397,11 @@ public static MurmurHash3Values hash(SortedBinaryDocValues values) {
             return new Bytes(values);
         }
 
+        /**
+         * Long hash value
+         *
+         * @opensearch.internal
+         */
         private static class Long extends MurmurHash3Values {
 
             private final SortedNumericDocValues values;
@@ -397,6 +426,11 @@ public long nextValue() throws IOException {
             }
         }
 
+        /**
+         * Double hash value
+         *
+         * @opensearch.internal
+         */
         private static class Double extends MurmurHash3Values {
 
             private final SortedNumericDoubleValues values;
@@ -421,6 +455,11 @@ public long nextValue() throws IOException {
             }
         }
 
+        /**
+         * Byte hash value
+         *
+         * @opensearch.internal
+         */
         private static class Bytes extends MurmurHash3Values {
 
             private final MurmurHash3.Hash128 hash = new MurmurHash3.Hash128();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorFactory.java
index 944cc4dc90771..980667b45324e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for cardinality agg
+ *
+ * @opensearch.internal
+ */
 class CardinalityAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final Long precisionThreshold;
@@ -84,6 +89,11 @@ protected Aggregator doCreateInternal(
             .build(name, config, precision(), searchContext, parent, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
     private int precision() {
         return precisionThreshold == null
             ? HyperLogLogPlusPlus.DEFAULT_PRECISION
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorSupplier.java
index 8ecd0fba9158a..d5cb0242762fd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorSupplier.java
@@ -39,6 +39,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for cardinality agg
+ *
+ * @opensearch.internal
+ */
 public interface CardinalityAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/CompensatedSum.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/CompensatedSum.java
index 0cf637885cfa2..151b0d5073909 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/CompensatedSum.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/CompensatedSum.java
@@ -40,6 +40,8 @@
  * truncation and rounding. These errors can lead to numerical instability.
  *
  * @see <a href="http://en.wikipedia.org/wiki/Kahan_summation_algorithm">Kahan Summation Algorithm</a>
+ *
+ * @opensearch.internal
  */
 public class CompensatedSum {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStats.java
index ed8ffc1e19e36..811a7e08caed3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStats.java
@@ -33,6 +33,8 @@
 
 /**
  * Statistics over a set of values (either aggregated over field data or scripts)
+ *
+ * @opensearch.internal
  */
 public interface ExtendedStats extends Stats {
 
@@ -116,6 +118,11 @@ public interface ExtendedStats extends Stats {
      */
     String getVarianceSamplingAsString();
 
+    /**
+     * The bounds of the extended stats
+     *
+     * @opensearch.internal
+     */
     enum Bounds {
         UPPER,
         LOWER,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregationBuilder.java
index cc01cba7c2a4a..91cce9137049d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for extended stats agg
+ *
+ * @opensearch.internal
+ */
 public class ExtendedStatsAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<
     ValuesSource.Numeric,
     ExtendedStatsAggregationBuilder> {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregator.java
index b973f2cb74213..a187e65511864 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregator.java
@@ -33,11 +33,11 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.ScoreMode;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.DoubleArray;
 import org.opensearch.common.util.LongArray;
+import org.opensearch.core.ParseField;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
@@ -51,6 +51,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into their extended statistics
+ *
+ * @opensearch.internal
+ */
 class ExtendedStatsAggregator extends NumericMetricsAggregator.MultiValue {
 
     static final ParseField SIGMA_FIELD = new ParseField("sigma");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorFactory.java
index f08d9630e8692..99b3d09517a1f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorFactory.java
@@ -47,6 +47,11 @@
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for extended_stats agg
+ *
+ * @opensearch.internal
+ */
 class ExtendedStatsAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final double sigma;
@@ -89,4 +94,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(ExtendedStatsAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, sigma, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorProvider.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorProvider.java
index ac86ebc2fc8aa..3c19c0b5867a1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorProvider.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorProvider.java
@@ -38,6 +38,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base supplier of an ExtendesStats aggregator
+ *
+ * @opensearch.internal
+ */
 public interface ExtendedStatsAggregatorProvider {
 
     Aggregator build(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregator.java
deleted file mode 100644
index 6d3b0796ac520..0000000000000
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregator.java
+++ /dev/null
@@ -1,195 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.metrics;
-
-import org.apache.lucene.index.LeafReaderContext;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.lease.Releasables;
-import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.DoubleArray;
-import org.opensearch.index.fielddata.MultiGeoPointValues;
-import org.opensearch.search.aggregations.Aggregator;
-import org.opensearch.search.aggregations.InternalAggregation;
-import org.opensearch.search.aggregations.LeafBucketCollector;
-import org.opensearch.search.aggregations.LeafBucketCollectorBase;
-import org.opensearch.search.aggregations.support.ValuesSource;
-import org.opensearch.search.aggregations.support.ValuesSourceConfig;
-import org.opensearch.search.internal.SearchContext;
-
-import java.io.IOException;
-import java.util.Map;
-
-final class GeoBoundsAggregator extends MetricsAggregator {
-
-    static final ParseField WRAP_LONGITUDE_FIELD = new ParseField("wrap_longitude");
-
-    private final ValuesSource.GeoPoint valuesSource;
-    private final boolean wrapLongitude;
-    DoubleArray tops;
-    DoubleArray bottoms;
-    DoubleArray posLefts;
-    DoubleArray posRights;
-    DoubleArray negLefts;
-    DoubleArray negRights;
-
-    GeoBoundsAggregator(
-        String name,
-        SearchContext aggregationContext,
-        Aggregator parent,
-        ValuesSourceConfig valuesSourceConfig,
-        boolean wrapLongitude,
-        Map<String, Object> metadata
-    ) throws IOException {
-        super(name, aggregationContext, parent, metadata);
-        // TODO: stop expecting nulls here
-        this.valuesSource = valuesSourceConfig.hasValues() ? (ValuesSource.GeoPoint) valuesSourceConfig.getValuesSource() : null;
-        this.wrapLongitude = wrapLongitude;
-        if (valuesSource != null) {
-            final BigArrays bigArrays = context.bigArrays();
-            tops = bigArrays.newDoubleArray(1, false);
-            tops.fill(0, tops.size(), Double.NEGATIVE_INFINITY);
-            bottoms = bigArrays.newDoubleArray(1, false);
-            bottoms.fill(0, bottoms.size(), Double.POSITIVE_INFINITY);
-            posLefts = bigArrays.newDoubleArray(1, false);
-            posLefts.fill(0, posLefts.size(), Double.POSITIVE_INFINITY);
-            posRights = bigArrays.newDoubleArray(1, false);
-            posRights.fill(0, posRights.size(), Double.NEGATIVE_INFINITY);
-            negLefts = bigArrays.newDoubleArray(1, false);
-            negLefts.fill(0, negLefts.size(), Double.POSITIVE_INFINITY);
-            negRights = bigArrays.newDoubleArray(1, false);
-            negRights.fill(0, negRights.size(), Double.NEGATIVE_INFINITY);
-        }
-    }
-
-    @Override
-    public LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCollector sub) {
-        if (valuesSource == null) {
-            return LeafBucketCollector.NO_OP_COLLECTOR;
-        }
-        final BigArrays bigArrays = context.bigArrays();
-        final MultiGeoPointValues values = valuesSource.geoPointValues(ctx);
-        return new LeafBucketCollectorBase(sub, values) {
-            @Override
-            public void collect(int doc, long bucket) throws IOException {
-                if (bucket >= tops.size()) {
-                    long from = tops.size();
-                    tops = bigArrays.grow(tops, bucket + 1);
-                    tops.fill(from, tops.size(), Double.NEGATIVE_INFINITY);
-                    bottoms = bigArrays.resize(bottoms, tops.size());
-                    bottoms.fill(from, bottoms.size(), Double.POSITIVE_INFINITY);
-                    posLefts = bigArrays.resize(posLefts, tops.size());
-                    posLefts.fill(from, posLefts.size(), Double.POSITIVE_INFINITY);
-                    posRights = bigArrays.resize(posRights, tops.size());
-                    posRights.fill(from, posRights.size(), Double.NEGATIVE_INFINITY);
-                    negLefts = bigArrays.resize(negLefts, tops.size());
-                    negLefts.fill(from, negLefts.size(), Double.POSITIVE_INFINITY);
-                    negRights = bigArrays.resize(negRights, tops.size());
-                    negRights.fill(from, negRights.size(), Double.NEGATIVE_INFINITY);
-                }
-
-                if (values.advanceExact(doc)) {
-                    final int valuesCount = values.docValueCount();
-
-                    for (int i = 0; i < valuesCount; ++i) {
-                        GeoPoint value = values.nextValue();
-                        double top = tops.get(bucket);
-                        if (value.lat() > top) {
-                            top = value.lat();
-                        }
-                        double bottom = bottoms.get(bucket);
-                        if (value.lat() < bottom) {
-                            bottom = value.lat();
-                        }
-                        double posLeft = posLefts.get(bucket);
-                        if (value.lon() >= 0 && value.lon() < posLeft) {
-                            posLeft = value.lon();
-                        }
-                        double posRight = posRights.get(bucket);
-                        if (value.lon() >= 0 && value.lon() > posRight) {
-                            posRight = value.lon();
-                        }
-                        double negLeft = negLefts.get(bucket);
-                        if (value.lon() < 0 && value.lon() < negLeft) {
-                            negLeft = value.lon();
-                        }
-                        double negRight = negRights.get(bucket);
-                        if (value.lon() < 0 && value.lon() > negRight) {
-                            negRight = value.lon();
-                        }
-                        tops.set(bucket, top);
-                        bottoms.set(bucket, bottom);
-                        posLefts.set(bucket, posLeft);
-                        posRights.set(bucket, posRight);
-                        negLefts.set(bucket, negLeft);
-                        negRights.set(bucket, negRight);
-                    }
-                }
-            }
-        };
-    }
-
-    @Override
-    public InternalAggregation buildAggregation(long owningBucketOrdinal) {
-        if (valuesSource == null) {
-            return buildEmptyAggregation();
-        }
-        double top = tops.get(owningBucketOrdinal);
-        double bottom = bottoms.get(owningBucketOrdinal);
-        double posLeft = posLefts.get(owningBucketOrdinal);
-        double posRight = posRights.get(owningBucketOrdinal);
-        double negLeft = negLefts.get(owningBucketOrdinal);
-        double negRight = negRights.get(owningBucketOrdinal);
-        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, metadata());
-    }
-
-    @Override
-    public InternalAggregation buildEmptyAggregation() {
-        return new InternalGeoBounds(
-            name,
-            Double.NEGATIVE_INFINITY,
-            Double.POSITIVE_INFINITY,
-            Double.POSITIVE_INFINITY,
-            Double.NEGATIVE_INFINITY,
-            Double.POSITIVE_INFINITY,
-            Double.NEGATIVE_INFINITY,
-            wrapLongitude,
-            metadata()
-        );
-    }
-
-    @Override
-    public void doClose() {
-        Releasables.close(tops, bottoms, posLefts, posRights, negLefts, negRights);
-    }
-}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorSupplier.java
index 38e2fc919cf5e..4fd2b7be494ea 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoBoundsAggregatorSupplier.java
@@ -39,6 +39,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for geo_bounds agg
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface GeoBoundsAggregatorSupplier {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroid.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroid.java
index 69f835e54ff0a..a5c13d15bacce 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroid.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroid.java
@@ -37,6 +37,8 @@
 
 /**
  * Interface for {@link GeoCentroidAggregator}
+ *
+ * @opensearch.internal
  */
 public interface GeoCentroid extends Aggregation {
     GeoPoint centroid();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregationBuilder.java
index dff3950fbe97b..bbbdfd60905b0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for geo_centroid agg
+ *
+ * @opensearch.internal
+ */
 public class GeoCentroidAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<
     ValuesSource.GeoPoint,
     GeoCentroidAggregationBuilder> {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregator.java
index a8e8907b61ccf..656211608433a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregator.java
@@ -52,6 +52,8 @@
 
 /**
  * A geo metric aggregator that computes a geo-centroid from a {@code geo_point} type field
+ *
+ * @opensearch.internal
  */
 final class GeoCentroidAggregator extends MetricsAggregator {
     private final ValuesSource.GeoPoint valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorFactory.java
index d8ad21d532522..a3fc91c6b62fb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for geo_centroid agg
+ *
+ * @opensearch.internal
+ */
 class GeoCentroidAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     GeoCentroidAggregatorFactory(
@@ -76,6 +81,11 @@ protected Aggregator doCreateInternal(
             .build(name, config, searchContext, parent, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(GeoCentroidAggregationBuilder.REGISTRY_KEY, CoreValuesSourceType.GEOPOINT, GeoCentroidAggregator::new, true);
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregator.java
index 959f0f82da4b8..bd1b3ae20f3f7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregator.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -41,6 +40,13 @@
 import java.io.IOException;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Aggregate all docs into an HDR percentile ranks values
+ *
+ * @opensearch.internal
+ */
 class HDRPercentileRanksAggregator extends AbstractHDRPercentilesAggregator {
 
     HDRPercentileRanksAggregator(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregator.java
index 83c6cf051cbd1..e468811af5996 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregator.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -41,6 +40,13 @@
 import java.io.IOException;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Aggregate all docs into a single HDR percentile
+ *
+ * @opensearch.internal
+ */
 class HDRPercentilesAggregator extends AbstractHDRPercentilesAggregator {
 
     HDRPercentilesAggregator(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlus.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlus.java
index 3408e8cf3bb5f..7bd1e1aa22a90 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlus.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlus.java
@@ -38,9 +38,9 @@
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.BitArray;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.ByteUtils;
 import org.opensearch.common.util.IntArray;
+import org.opensearch.core.common.util.ByteArray;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -60,6 +60,8 @@
  * to the HyperLogLog algorithm and then this is used.
  *
  * It supports storing several HyperLogLogPlusPlus structures which are identified by a bucket number.
+ *
+ * @opensearch.internal
  */
 public final class HyperLogLogPlusPlus extends AbstractHyperLogLogPlusPlus {
 
@@ -223,16 +225,20 @@ private void merge(long thisBucket, AbstractHyperLogLog.RunLenIterator runLens)
         }
     }
 
+    /**
+     * The hyper log log
+     *
+     * @opensearch.internal
+     */
     private static class HyperLogLog extends AbstractHyperLogLog implements Releasable {
         private final BigArrays bigArrays;
         private final HyperLogLogIterator iterator;
         // array for holding the runlens.
         private ByteArray runLens;
 
-
         HyperLogLog(BigArrays bigArrays, long initialBucketCount, int precision) {
             super(precision);
-            this.runLens =  bigArrays.newByteArray(initialBucketCount << precision);
+            this.runLens = bigArrays.newByteArray(initialBucketCount << precision);
             this.bigArrays = bigArrays;
             this.iterator = new HyperLogLogIterator(this, precision, m);
         }
@@ -267,6 +273,11 @@ public void close() {
         }
     }
 
+    /**
+     * Iterator for hyper log log
+     *
+     * @opensearch.internal
+     */
     private static class HyperLogLogIterator implements AbstractHyperLogLog.RunLenIterator {
 
         private final HyperLogLog hll;
@@ -302,6 +313,11 @@ public byte value() {
         }
     }
 
+    /**
+     * The plus plus
+     *
+     * @opensearch.internal
+     */
     private static class LinearCounting extends AbstractLinearCounting implements Releasable {
 
         protected final int threshold;
@@ -395,6 +411,11 @@ public void close() {
         }
     }
 
+    /**
+     * The plus plus iterator
+     *
+     * @opensearch.internal
+     */
     private static class LinearCountingIterator implements AbstractLinearCounting.HashesIterator {
 
         private final LinearCounting lc;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparse.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparse.java
index 1a7a544d26bc9..252df7358ddcd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparse.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparse.java
@@ -43,6 +43,8 @@
  *
  * This structure expects all the added values to be distinct and therefore there are no checks
  * if an element has been previously added.
+ *
+ * @opensearch.internal
  */
 final class HyperLogLogPlusPlusSparse extends AbstractHyperLogLogPlusPlus implements Releasable {
 
@@ -96,6 +98,11 @@ protected void addEncoded(long bucket, int encoded) {
         lc.addEncoded(bucket, encoded);
     }
 
+    /**
+     * The plus plus
+     *
+     * @opensearch.internal
+     */
     private static class LinearCounting extends AbstractLinearCounting implements Releasable {
 
         private final int capacity;
@@ -187,6 +194,11 @@ public void close() {
         }
     }
 
+    /**
+     * The plus plus iterator
+     *
+     * @opensearch.internal
+     */
     private static class LinearCountingIterator implements AbstractLinearCounting.HashesIterator {
 
         private final LinearCounting lc;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalAvg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalAvg.java
index ddbae8b37b33f..36c354b57d3b2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalAvg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalAvg.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of internal agg
+ *
+ * @opensearch.internal
+ */
 public class InternalAvg extends InternalNumericMetricsAggregation.SingleValue implements Avg {
     private final double sum;
     private final long count;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalCardinality.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalCardinality.java
index 234e20393fa98..7e9511ffdd379 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalCardinality.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalCardinality.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of cardinality agg
+ *
+ * @opensearch.internal
+ */
 public final class InternalCardinality extends InternalNumericMetricsAggregation.SingleValue implements Cardinality {
     private final AbstractHyperLogLogPlusPlus counts;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalExtendedStats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalExtendedStats.java
index 34d87d92dbbdb..3e4521e973aac 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalExtendedStats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalExtendedStats.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,7 +42,17 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of extended stats agg
+ *
+ * @opensearch.internal
+ */
 public class InternalExtendedStats extends InternalStats implements ExtendedStats {
+    /**
+     * The metrics for the extended stats
+     *
+     * @opensearch.internal
+     */
     enum Metrics {
 
         count,
@@ -299,6 +309,11 @@ public InternalExtendedStats reduce(List<InternalAggregation> aggregations, Redu
         );
     }
 
+    /**
+     * Fields for internal extended stats
+     *
+     * @opensearch.internal
+     */
     static class Fields {
         public static final String SUM_OF_SQRS = "sum_of_squares";
         public static final String SUM_OF_SQRS_AS_STRING = "sum_of_squares_as_string";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoCentroid.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoCentroid.java
index c043cca5d6c6f..9d401568d360e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoCentroid.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalGeoCentroid.java
@@ -34,11 +34,11 @@
 
 import org.apache.lucene.geo.GeoEncodingUtils;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 
 import java.io.IOException;
@@ -48,6 +48,8 @@
 
 /**
  * Serialization and merge logic for {@link GeoCentroidAggregator}.
+ *
+ * @opensearch.internal
  */
 public class InternalGeoCentroid extends InternalAggregation implements GeoCentroid {
     private final GeoPoint centroid;
@@ -175,6 +177,11 @@ public Object getProperty(List<String> path) {
         }
     }
 
+    /**
+     * Fields for geo centroid
+     *
+     * @opensearch.internal
+     */
     static class Fields {
         static final ParseField CENTROID = new ParseField("location");
         static final ParseField COUNT = new ParseField("count");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
index eb11d4bda33e3..5517a035fc2e1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentileRanks.java
@@ -31,14 +31,20 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Implementation of HDR percentiles ranks
+ *
+ * @opensearch.internal
+ */
 public class InternalHDRPercentileRanks extends AbstractInternalHDRPercentiles implements PercentileRanks {
     public static final String NAME = "hdr_percentile_ranks";
 
@@ -109,6 +115,11 @@ public static double percentileRank(DoubleHistogram state, double value) {
         return percentileRank;
     }
 
+    /**
+     * Terator for HDR percentile ranks agg
+     *
+     * @opensearch.internal
+     */
     public static class Iter implements Iterator<Percentile> {
 
         private final double[] values;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentiles.java
index 2ba910fee43c9..db5a7061af77f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentiles.java
@@ -31,14 +31,20 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
+/**
+ * Implementation of HDR percentiles agg
+ *
+ * @opensearch.internal
+ */
 public class InternalHDRPercentiles extends AbstractInternalHDRPercentiles implements Percentiles {
     public static final String NAME = "hdr_percentiles";
 
@@ -99,6 +105,11 @@ protected AbstractInternalHDRPercentiles createReduced(
         return new InternalHDRPercentiles(name, keys, merged, keyed, format, metadata);
     }
 
+    /**
+     * Iterator for HDR percentiles
+     *
+     * @opensearch.internal
+     */
     public static class Iter implements Iterator<Percentile> {
 
         private final double[] percents;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMax.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMax.java
index 675f82eda8add..2abb2106681ff 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMax.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMax.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of max agg
+ *
+ * @opensearch.internal
+ */
 public class InternalMax extends InternalNumericMetricsAggregation.SingleValue implements Max {
     private final double max;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMedianAbsoluteDeviation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMedianAbsoluteDeviation.java
index 9066709b8bfaa..1f9e6b0050420 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMedianAbsoluteDeviation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMedianAbsoluteDeviation.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -43,6 +43,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of median absolute deviation agg
+ *
+ * @opensearch.internal
+ */
 public class InternalMedianAbsoluteDeviation extends InternalNumericMetricsAggregation.SingleValue implements MedianAbsoluteDeviation {
 
     static double computeMedianAbsoluteDeviation(TDigestState valuesSketch) {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMin.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMin.java
index ba00bc457ff83..bda0fda82a0d7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMin.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalMin.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of min agg
+ *
+ * @opensearch.internal
+ */
 public class InternalMin extends InternalNumericMetricsAggregation.SingleValue implements Min {
     private final double min;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalNumericMetricsAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalNumericMetricsAggregation.java
index e7c43794d3963..a5508d34589ed 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalNumericMetricsAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalNumericMetricsAggregation.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.support.AggregationPath;
@@ -42,12 +42,22 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Base aggregation to aggregate all docs into a single numeric metric
+ *
+ * @opensearch.internal
+ */
 public abstract class InternalNumericMetricsAggregation extends InternalAggregation {
 
     private static final DocValueFormat DEFAULT_FORMAT = DocValueFormat.RAW;
 
     protected DocValueFormat format = DEFAULT_FORMAT;
 
+    /**
+     * A single numeric metric value
+     *
+     * @opensearch.internal
+     */
     public abstract static class SingleValue extends InternalNumericMetricsAggregation implements NumericMetricsAggregation.SingleValue {
         protected SingleValue(String name, Map<String, Object> metadata) {
             super(name, metadata);
@@ -91,6 +101,11 @@ public final double sortValue(String key) {
         }
     }
 
+    /**
+     * Multe numeric metric values
+     *
+     * @opensearch.internal
+     */
     public abstract static class MultiValue extends InternalNumericMetricsAggregation implements NumericMetricsAggregation.MultiValue {
         protected MultiValue(String name, Map<String, Object> metadata) {
             super(name, metadata);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetric.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetric.java
index a9924916de1de..318f0c9fdb22e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetric.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetric.java
@@ -33,10 +33,10 @@
 package org.opensearch.search.aggregations.metrics;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptedMetricAggContexts;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -51,6 +51,11 @@
 
 import static java.util.Collections.singletonList;
 
+/**
+ * Implementation of scripted metric agg
+ *
+ * @opensearch.internal
+ */
 public class InternalScriptedMetric extends InternalAggregation implements ScriptedMetric {
     final Script reduceScript;
     private final List<Object> aggregations;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalStats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalStats.java
index 6c6953633c799..d21e44ca8e55c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalStats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalStats.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,7 +42,17 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of stats agg
+ *
+ * @opensearch.internal
+ */
 public class InternalStats extends InternalNumericMetricsAggregation.MultiValue implements Stats {
+    /**
+     * The metrics for the internal stats
+     *
+     * @opensearch.internal
+     */
     enum Metrics {
 
         count,
@@ -190,6 +200,11 @@ public InternalStats reduce(List<InternalAggregation> aggregations, ReduceContex
         return new InternalStats(name, count, kahanSummation.value(), min, max, format, getMetadata());
     }
 
+    /**
+     * Fields for stats agg
+     *
+     * @opensearch.internal
+     */
     static class Fields {
         public static final String COUNT = "count";
         public static final String MIN = "min";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalSum.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalSum.java
index 174b697839659..51d50ca4240ca 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalSum.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalSum.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of sum agg
+ *
+ * @opensearch.internal
+ */
 public class InternalSum extends InternalNumericMetricsAggregation.SingleValue implements Sum {
     private final double sum;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
index 65d3ece0bbb40..3ff813d5ba69c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentileRanks.java
@@ -31,13 +31,18 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
 
+/**
+ * Implementation of TDigest percentiles rank agg
+ *
+ * @opensearch.internal
+ */
 public class InternalTDigestPercentileRanks extends AbstractInternalTDigestPercentiles implements PercentileRanks {
     public static final String NAME = "tdigest_percentile_ranks";
 
@@ -105,6 +110,11 @@ public static double percentileRank(TDigestState state, double value) {
         return percentileRank * 100;
     }
 
+    /**
+     * Iter for the TDigest percentile ranks agg
+     *
+     * @opensearch.internal
+     */
     public static class Iter implements Iterator<Percentile> {
 
         private final double[] values;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentiles.java
index 1988d03ca5e4b..cc1f63614f9ef 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTDigestPercentiles.java
@@ -31,13 +31,18 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
 
+/**
+ * Implementation of TDigest percentiles agg
+ *
+ * @opensearch.internal
+ */
 public class InternalTDigestPercentiles extends AbstractInternalTDigestPercentiles implements Percentiles {
     public static final String NAME = "tdigest_percentiles";
 
@@ -95,6 +100,11 @@ protected AbstractInternalTDigestPercentiles createReduced(
         return new InternalTDigestPercentiles(name, keys, merged, keyed, format, metadata);
     }
 
+    /**
+     * Iter for the TDigest percentiles agg
+     *
+     * @opensearch.internal
+     */
     public static class Iter implements Iterator<Percentile> {
 
         private final double[] percents;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTopHits.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTopHits.java
index 24e7875a6ade9..e82f49aa13600 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTopHits.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalTopHits.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits.Relation;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -53,6 +53,8 @@
 
 /**
  * Results of the {@link TopHitsAggregator}.
+ *
+ * @opensearch.internal
  */
 public class InternalTopHits extends InternalAggregation implements TopHits {
     private int from;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalValueCount.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalValueCount.java
index 7e839a6874ee1..ede89b1369ae8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalValueCount.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalValueCount.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.InternalAggregation;
 
 import java.io.IOException;
@@ -43,6 +43,8 @@
 
 /**
  * An internal implementation of {@link ValueCount}.
+ *
+ * @opensearch.internal
  */
 public class InternalValueCount extends InternalNumericMetricsAggregation.SingleValue implements ValueCount {
     private final long value;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalWeightedAvg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalWeightedAvg.java
index 6e2cf0dc6d326..57cfbcb475f83 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalWeightedAvg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/InternalWeightedAvg.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of weighted avg agg
+ *
+ * @opensearch.internal
+ */
 public class InternalWeightedAvg extends InternalNumericMetricsAggregation.SingleValue implements WeightedAvg {
     private final double sum;
     private final double weight;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Max.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Max.java
index 24a0c834b597d..5834173e10ea5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Max.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Max.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes the maximum of the values in the current bucket.
+ *
+ * @opensearch.internal
  */
 public interface Max extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregationBuilder.java
index 4cdc73a08dd20..ae16efb09d3fa 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for max agg
+ *
+ * @opensearch.internal
+ */
 public class MaxAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource.Numeric, MaxAggregationBuilder> {
     public static final String NAME = "max";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregator.java
index b755d54de0fe5..8108b8a726856 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregator.java
@@ -57,6 +57,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Aggregate all docs into a max value
+ *
+ * @opensearch.internal
+ */
 class MaxAggregator extends NumericMetricsAggregator.SingleValue {
 
     final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregatorFactory.java
index 2541f8fdf0bbb..4fe936c8b7797 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MaxAggregatorFactory.java
@@ -44,14 +44,20 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for max agg
+ *
+ * @opensearch.internal
+ */
 class MaxAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             MaxAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             MaxAggregator::new,
             true
         );
@@ -84,4 +90,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(MaxAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviation.java
index 34437b7c91621..0c989f627309d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviation.java
@@ -36,6 +36,8 @@
  * An aggregation that approximates the median absolute deviation of a numeric field
  *
  * @see <a href="https://en.wikipedia.org/wiki/Median_absolute_deviation">https://en.wikipedia.org/wiki/Median_absolute_deviation</a>
+ *
+ * @opensearch.internal
  */
 public interface MedianAbsoluteDeviation extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregationBuilder.java
index 09faa958f821c..7e59d0abc5419 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -54,6 +54,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for median_absolute_deviation agg
+ *
+ * @opensearch.internal
+ */
 public class MedianAbsoluteDeviationAggregationBuilder extends LeafOnly<ValuesSource.Numeric, MedianAbsoluteDeviationAggregationBuilder> {
 
     public static final String NAME = "median_absolute_deviation";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregator.java
index 24c26d695c715..0b4684452a8dc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregator.java
@@ -53,6 +53,11 @@
 
 import static org.opensearch.search.aggregations.metrics.InternalMedianAbsoluteDeviation.computeMedianAbsoluteDeviation;
 
+/**
+ * Aggregate all docs into a median absolute deviation
+ *
+ * @opensearch.internal
+ */
 public class MedianAbsoluteDeviationAggregator extends NumericMetricsAggregator.SingleValue {
 
     private final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorFactory.java
index e749fe4db0866..3ef3c2afc7875 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for median_absolute_deviation agg
+ *
+ * @opensearch.internal
+ */
 public class MedianAbsoluteDeviationAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final double compression;
@@ -90,4 +95,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(MedianAbsoluteDeviationAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config.getValuesSource(), config.format(), searchContext, parent, metadata, compression);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorSupplier.java
index 6ae211719217b..986e32cf438cd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorSupplier.java
@@ -39,6 +39,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for median_absolute_deviation agg
+ *
+ * @opensearch.internal
+ */
 public interface MedianAbsoluteDeviationAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricAggregatorSupplier.java
index f260da8a2638c..4e70d417c4b91 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricAggregatorSupplier.java
@@ -38,6 +38,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for metric aggs
+ *
+ * @opensearch.internal
+ */
 public interface MetricAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricInspectionHelper.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricInspectionHelper.java
index 2ed48a97bc381..47e27da5394b3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricInspectionHelper.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricInspectionHelper.java
@@ -38,6 +38,8 @@
  * helpers for some aggs that have package-private getters.  AggregationInspectionHelper delegates to these
  * helpers when needed, and consumers should prefer to use AggregationInspectionHelper instead of these
  * helpers.
+ *
+ * @opensearch.internal
  */
 public class MetricInspectionHelper {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricsAggregator.java
index f59daeb469009..0929fc60b02c9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MetricsAggregator.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base aggregator to aggregate all docs into a single metric
+ *
+ * @opensearch.internal
+ */
 public abstract class MetricsAggregator extends AggregatorBase {
     protected MetricsAggregator(String name, SearchContext context, Aggregator parent, Map<String, Object> metadata) throws IOException {
         super(name, AggregatorFactories.EMPTY, context, parent, CardinalityUpperBound.NONE, metadata);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Min.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Min.java
index dd3aea059e826..b99e08c9df86c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Min.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Min.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes the minimum of the values in the current bucket.
+ *
+ * @opensearch.internal
  */
 public interface Min extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregationBuilder.java
index 89797710a40f7..770d58c966320 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for min agg
+ *
+ * @opensearch.internal
+ */
 public class MinAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource.Numeric, MinAggregationBuilder> {
     public static final String NAME = "min";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregator.java
index 372fd936fa766..946057e42ac88 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregator.java
@@ -56,6 +56,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Aggregate all docs into a min value
+ *
+ * @opensearch.internal
+ */
 class MinAggregator extends NumericMetricsAggregator.SingleValue {
     private static final int MAX_BKD_LOOKUPS = 1024;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregatorFactory.java
index 3db64aa05bb6c..58fbe5edefd12 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/MinAggregatorFactory.java
@@ -44,14 +44,20 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for min agg
+ *
+ * @opensearch.internal
+ */
 class MinAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             MinAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             MinAggregator::new,
             true
         );
@@ -84,4 +90,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(MinAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregation.java
index acde7bc6f3d4e..d36976d8b703d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregation.java
@@ -34,8 +34,18 @@
 
 import org.opensearch.search.aggregations.Aggregation;
 
+/**
+ * Base numeric metrics aggregation class
+ *
+ * @opensearch.internal
+ */
 public interface NumericMetricsAggregation extends Aggregation {
 
+    /**
+     * A single value for the metrics agg
+     *
+     * @opensearch.internal
+     */
     interface SingleValue extends NumericMetricsAggregation {
 
         double value();
@@ -44,5 +54,10 @@ interface SingleValue extends NumericMetricsAggregation {
 
     }
 
+    /**
+     * Multi values in a numeric metrics agg
+     *
+     * @opensearch.internal
+     */
     interface MultiValue extends NumericMetricsAggregation {}
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregator.java
index 9a4c0be0b7c47..f90e5a092385f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/NumericMetricsAggregator.java
@@ -39,6 +39,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base class to aggregate all docs into a single numeric metric value.
+ *
+ * @opensearch.internal
+ */
 public abstract class NumericMetricsAggregator extends MetricsAggregator {
 
     private NumericMetricsAggregator(String name, SearchContext context, Aggregator parent, Map<String, Object> metadata)
@@ -46,6 +51,11 @@ private NumericMetricsAggregator(String name, SearchContext context, Aggregator
         super(name, context, parent, metadata);
     }
 
+    /**
+     * Single numeric metric agg value
+     *
+     * @opensearch.internal
+     */
     public abstract static class SingleValue extends NumericMetricsAggregator {
 
         protected SingleValue(String name, SearchContext context, Aggregator parent, Map<String, Object> metadata) throws IOException {
@@ -70,6 +80,11 @@ public BucketComparator bucketComparator(String key, SortOrder order) {
         }
     }
 
+    /**
+     * Multi numeric metric agg value
+     *
+     * @opensearch.internal
+     */
     public abstract static class MultiValue extends NumericMetricsAggregator {
 
         protected MultiValue(String name, SearchContext context, Aggregator parent, Map<String, Object> metadata) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedAvg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedAvg.java
index 1242f61e75ac8..d33d547285f60 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedAvg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedAvg.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * An average agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedAvg extends ParsedSingleValueNumericMetricsAggregation implements Avg {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedCardinality.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedCardinality.java
index 99bb36b900c23..a212c24f6859c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedCardinality.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedCardinality.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
 
+/**
+ * A cardinality agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedCardinality extends ParsedAggregation implements Cardinality {
 
     private long cardinalityValue;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedExtendedStats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedExtendedStats.java
index 1cc0ab59030db..8331b9be7175d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedExtendedStats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedExtendedStats.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.InternalExtendedStats.Fields;
 
 import java.io.IOException;
@@ -45,9 +45,14 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
+/**
+ * An extended stats agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedExtendedStats extends ParsedStats implements ExtendedStats {
 
     protected double sumOfSquares;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoCentroid.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoCentroid.java
index 06e099f9709ea..782470f2576e1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoCentroid.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedGeoCentroid.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.metrics;
 
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 import org.opensearch.search.aggregations.metrics.InternalGeoCentroid.Fields;
 
@@ -43,6 +43,8 @@
 
 /**
  * Serialization and merge logic for {@link GeoCentroidAggregator}.
+ *
+ * @opensearch.internal
  */
 public class ParsedGeoCentroid extends ParsedAggregation implements GeoCentroid {
     private GeoPoint centroid;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentileRanks.java
index 5faa795d8b630..2e53bc5bed4e2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentileRanks.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Iterator;
 
+/**
+ * An HDR agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedHDRPercentileRanks extends ParsedPercentileRanks {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentiles.java
index f7a4afb86be3e..d200f66dc3003 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedHDRPercentiles.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * An HDR percentiles agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedHDRPercentiles extends ParsedPercentiles implements Percentiles {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMax.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMax.java
index 2862a629ab747..b574f7a4d749e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMax.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMax.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A max agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedMax extends ParsedSingleValueNumericMetricsAggregation implements Max {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMedianAbsoluteDeviation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMedianAbsoluteDeviation.java
index 001e44736ae2a..185b2a9d59634 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMedianAbsoluteDeviation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMedianAbsoluteDeviation.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A median absolute deviation agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedMedianAbsoluteDeviation extends ParsedSingleValueNumericMetricsAggregation implements MedianAbsoluteDeviation {
 
     private static final ObjectParser<ParsedMedianAbsoluteDeviation, Void> PARSER = new ObjectParser<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMin.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMin.java
index 711a4e94b0e7a..0ff4a50c39d7e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMin.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedMin.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A min agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedMin extends ParsedSingleValueNumericMetricsAggregation implements Min {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentileRanks.java
index 71773e80405e9..be57e85962e8d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentileRanks.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+/**
+ * A percentiles agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 abstract class ParsedPercentileRanks extends ParsedPercentiles implements PercentileRanks {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentiles.java
index 06f8eba1f46ff..7da9137b35e73 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedPercentiles.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
@@ -43,6 +43,11 @@
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+/**
+ * A single percentiles agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedPercentiles extends ParsedAggregation implements Iterable<Percentile> {
 
     protected final Map<Double, Double> percentiles = new LinkedHashMap<>();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedScriptedMetric.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedScriptedMetric.java
index b7bc5a7d2c39c..760adf2b7a350 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedScriptedMetric.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedScriptedMetric.java
@@ -32,18 +32,23 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * A scripted metric result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedScriptedMetric extends ParsedAggregation implements ScriptedMetric {
     private List<Object> aggregation;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSingleValueNumericMetricsAggregation.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSingleValueNumericMetricsAggregation.java
index ae657e203fc2f..97a6e363c732c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSingleValueNumericMetricsAggregation.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSingleValueNumericMetricsAggregation.java
@@ -31,10 +31,15 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
+/**
+ * A single value numeric agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class ParsedSingleValueNumericMetricsAggregation extends ParsedAggregation
     implements
         NumericMetricsAggregation.SingleValue {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedStats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedStats.java
index 55258f1e10973..d11820ba42d12 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedStats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedStats.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 import org.opensearch.search.aggregations.metrics.InternalStats.Fields;
 
@@ -44,6 +44,11 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * A stats agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedStats extends ParsedAggregation implements Stats {
 
     protected long count;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSum.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSum.java
index 2f5d8fca16636..f7fbef7ad1cab 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSum.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedSum.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A sum agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedSum extends ParsedSingleValueNumericMetricsAggregation implements Sum {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentileRanks.java
index f1cfaf3f08848..a670e70e44aed 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentileRanks.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Iterator;
 
+/**
+ * A TDigest percentiles rank agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedTDigestPercentileRanks extends ParsedPercentileRanks {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentiles.java
index 9b6090c3de2e3..271a9698f43c2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTDigestPercentiles.java
@@ -32,11 +32,16 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A single TDigest percentiles result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedTDigestPercentiles extends ParsedPercentiles implements Percentiles {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTopHits.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTopHits.java
index 9d52e71cbfe6b..66b406a3e90ad 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTopHits.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedTopHits.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
 
+/**
+ * A top_hits agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedTopHits extends ParsedAggregation implements TopHits {
 
     private SearchHits searchHits;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedValueCount.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedValueCount.java
index 305cee740648c..97f82b8ca6ee3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedValueCount.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedValueCount.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.ParsedAggregation;
 
 import java.io.IOException;
 
+/**
+ * A value count agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedValueCount extends ParsedAggregation implements ValueCount {
 
     private long valueCount;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedWeightedAvg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedWeightedAvg.java
index 680f6274c8e21..d405884ba864f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedWeightedAvg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ParsedWeightedAvg.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A weighted average agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedWeightedAvg extends ParsedSingleValueNumericMetricsAggregation implements WeightedAvg {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentile.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentile.java
index d797e602b2d80..50ebd6f343fc2 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentile.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentile.java
@@ -34,6 +34,11 @@
 
 import java.util.Objects;
 
+/**
+ * Implementation of a percentile
+ *
+ * @opensearch.internal
+ */
 public class Percentile {
 
     private final double percent;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanks.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanks.java
index 00725b20f8015..b4a6dc39a442e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanks.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanks.java
@@ -34,6 +34,8 @@
 
 /**
  * An aggregation that computes approximate percentiles given values.
+ *
+ * @opensearch.internal
  */
 public interface PercentileRanks extends NumericMetricsAggregation.MultiValue, Iterable<Percentile> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregationBuilder.java
index 037830c63ecdf..7585844b6bbb9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -49,6 +49,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for percentile_ranks agg
+ *
+ * @opensearch.internal
+ */
 public class PercentileRanksAggregationBuilder extends AbstractPercentilesAggregationBuilder<PercentileRanksAggregationBuilder> {
     public static final String NAME = PercentileRanks.TYPE_NAME;
     public static final ValuesSourceRegistry.RegistryKey<PercentilesAggregatorSupplier> REGISTRY_KEY =
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregatorFactory.java
index 059b9dd7d0d1c..d3c18bcad1a43 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentileRanksAggregatorFactory.java
@@ -47,6 +47,11 @@
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Base Aggregation Factory for ranks aggs
+ *
+ * @opensearch.internal
+ */
 class PercentileRanksAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     private final double[] percents;
@@ -106,4 +111,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(PercentileRanksAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config.getValuesSource(), searchContext, parent, percents, percentilesConfig, keyed, config.format(), metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentiles.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentiles.java
index 5b40a2ce8f2f3..f6bf9d1f82348 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentiles.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Percentiles.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes approximate percentiles.
+ *
+ * @opensearch.internal
  */
 public interface Percentiles extends NumericMetricsAggregation.MultiValue, Iterable<Percentile> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregationBuilder.java
index 323723bb6deb1..38c6e99003828 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.util.Arrays;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for percentiles agg
+ *
+ * @opensearch.internal
+ */
 public class PercentilesAggregationBuilder extends AbstractPercentilesAggregationBuilder<PercentilesAggregationBuilder> {
     public static final String NAME = Percentiles.TYPE_NAME;
     public static final ValuesSourceRegistry.RegistryKey<PercentilesAggregatorSupplier> REGISTRY_KEY =
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorFactory.java
index 15f3010719916..148e26e038923 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorFactory.java
@@ -50,6 +50,8 @@
 /**
  * This factory is used to generate both TDigest and HDRHisto aggregators, depending
  * on the selected method
+ *
+ * @opensearch.internal
  */
 class PercentilesAggregatorFactory extends ValuesSourceAggregatorFactory {
 
@@ -101,4 +103,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(PercentilesAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config.getValuesSource(), searchContext, parent, percents, percentilesConfig, keyed, config.format(), metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorSupplier.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorSupplier.java
index d65619be5bc0e..8f6e36a3ac8e1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorSupplier.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesAggregatorSupplier.java
@@ -39,6 +39,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregator supplier interface for percentiles aggs
+ *
+ * @opensearch.internal
+ */
 public interface PercentilesAggregatorSupplier {
     Aggregator build(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesConfig.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesConfig.java
index 26ef2727832bc..58f2076b2891d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesConfig.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesConfig.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.support.ValuesSource;
@@ -50,6 +50,8 @@
  * A small config object that carries algo-specific settings.  This allows the factory to have
  * a single unified constructor for both algos, but internally switch execution
  * depending on which algo is selected
+ *
+ * @opensearch.internal
  */
 public abstract class PercentilesConfig implements ToXContent, Writeable {
     private final PercentilesMethod method;
@@ -121,6 +123,11 @@ public int hashCode() {
         return Objects.hash(method);
     }
 
+    /**
+     * The TDigest
+     *
+     * @opensearch.internal
+     */
     public static class TDigest extends PercentilesConfig {
         static final double DEFAULT_COMPRESSION = 100.0;
         private double compression;
@@ -217,6 +224,11 @@ public int hashCode() {
         }
     }
 
+    /**
+     * The HDR value
+     *
+     * @opensearch.internal
+     */
     public static class Hdr extends PercentilesConfig {
         static final int DEFAULT_NUMBER_SIG_FIGS = 3;
         private int numberOfSignificantValueDigits;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesMethod.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesMethod.java
index b167251861bc2..dfd3905392685 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesMethod.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/PercentilesMethod.java
@@ -32,16 +32,18 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
 
 import java.io.IOException;
 
 /**
  * An enum representing the methods for calculating percentiles
+ *
+ * @opensearch.internal
  */
 public enum PercentilesMethod implements Writeable {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetric.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetric.java
index 3cf6da01e0f43..487e7c9de22d6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetric.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetric.java
@@ -36,6 +36,8 @@
 
 /**
  * A metric aggregation that computes both its final and intermediate states using scripts.
+ *
+ * @opensearch.internal
  */
 public interface ScriptedMetric extends Aggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregationBuilder.java
index 4564977f09471..419837dde788e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptedMetricAggContexts;
@@ -50,8 +50,13 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
+/**
+ * Aggregation Builder for scripted_metric agg
+ *
+ * @opensearch.internal
+ */
 public class ScriptedMetricAggregationBuilder extends AbstractAggregationBuilder<ScriptedMetricAggregationBuilder> {
     public static final String NAME = "scripted_metric";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregator.java
index 8ff0e33afbcf9..8e04bbae41107 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregator.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.ScoreMode;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasables;
-import org.opensearch.common.util.CollectionUtils;
 import org.opensearch.common.util.ObjectArray;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptedMetricAggContexts;
 import org.opensearch.script.ScriptedMetricAggContexts.MapScript;
@@ -56,6 +56,11 @@
 
 import static java.util.Collections.singletonList;
 
+/**
+ * Aggregate all docs based on a value script
+ *
+ * @opensearch.internal
+ */
 class ScriptedMetricAggregator extends MetricsAggregator {
     /**
      * Estimated cost to maintain a bucket. Since this aggregator uses
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorFactory.java
index 53e865b2f04b7..58ef54ed64482 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorFactory.java
@@ -50,6 +50,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for scripted_metrics agg
+ *
+ * @opensearch.internal
+ */
 class ScriptedMetricAggregatorFactory extends AggregatorFactory {
 
     private final ScriptedMetricAggContexts.MapScript.Factory mapScript;
@@ -98,7 +103,7 @@ public Aggregator createInternal(
         CardinalityUpperBound cardinality,
         Map<String, Object> metadata
     ) throws IOException {
-        Map<String, Object> aggParams = this.aggParams == null ? org.opensearch.common.collect.Map.of() : this.aggParams;
+        Map<String, Object> aggParams = this.aggParams == null ? Map.of() : this.aggParams;
 
         Script reduceScript = deepCopyScript(this.reduceScript, searchContext, aggParams);
 
@@ -119,6 +124,11 @@ public Aggregator createInternal(
         );
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
+
     private static Script deepCopyScript(Script script, SearchContext context, Map<String, Object> aggParams) {
         if (script != null) {
             Map<String, Object> params = mergeParams(aggParams, deepCopyParams(script.getParams(), context));
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Stats.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Stats.java
index 4228996f426df..4e854196f387b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Stats.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Stats.java
@@ -33,6 +33,8 @@
 
 /**
  * Statistics over a set of values (either aggregated over field data or scripts)
+ *
+ * @opensearch.internal
  */
 public interface Stats extends NumericMetricsAggregation.MultiValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregationBuilder.java
index da38127c80d2d..99c55cfc3ceba 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for stats agg
+ *
+ * @opensearch.internal
+ */
 public class StatsAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource.Numeric, StatsAggregationBuilder> {
     public static final String NAME = "stats";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregator.java
index 069721e37531f..c52638fe4b9c6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregator.java
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into their basic descriptive statistics
+ *
+ * @opensearch.internal
+ */
 class StatsAggregator extends NumericMetricsAggregator.MultiValue {
 
     final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregatorFactory.java
index 01772df17a925..0e96e631044dd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/StatsAggregatorFactory.java
@@ -44,8 +44,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for stats agg
+ *
+ * @opensearch.internal
+ */
 class StatsAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     StatsAggregatorFactory(
@@ -62,7 +68,7 @@ class StatsAggregatorFactory extends ValuesSourceAggregatorFactory {
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             StatsAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             StatsAggregator::new,
             true
         );
@@ -84,4 +90,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(StatsAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/Sum.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/Sum.java
index cee960280e052..e58a9e504cf04 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/Sum.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/Sum.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes the sum of the values in the current bucket.
+ *
+ * @opensearch.internal
  */
 public interface Sum extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregationBuilder.java
index dee421d8bd38a..ec84a22037257 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -50,6 +50,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for sum agg
+ *
+ * @opensearch.internal
+ */
 public class SumAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource.Numeric, SumAggregationBuilder> {
     public static final String NAME = "sum";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregator.java
index 82799d8e9f3a1..4b8e882cd69bc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregator.java
@@ -49,6 +49,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a single sum value
+ *
+ * @opensearch.internal
+ */
 public class SumAggregator extends NumericMetricsAggregator.SingleValue {
 
     private final ValuesSource.Numeric valuesSource;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregatorFactory.java
index c05b438b0680f..ef9b93920ba18 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/SumAggregatorFactory.java
@@ -44,8 +44,14 @@
 import org.opensearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for sum agg
+ *
+ * @opensearch.internal
+ */
 class SumAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     SumAggregatorFactory(
@@ -62,7 +68,7 @@ class SumAggregatorFactory extends ValuesSourceAggregatorFactory {
     static void registerAggregators(ValuesSourceRegistry.Builder builder) {
         builder.register(
             SumAggregationBuilder.REGISTRY_KEY,
-            org.opensearch.common.collect.List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
+            List.of(CoreValuesSourceType.NUMERIC, CoreValuesSourceType.DATE, CoreValuesSourceType.BOOLEAN),
             SumAggregator::new,
             true
         );
@@ -84,4 +90,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(SumAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregator.java
index c61a55950b7d2..8c7b71561ed9d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregator.java
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a the TDigenst Percentile Ranks
+ *
+ * @opensearch.internal
+ */
 class TDigestPercentileRanksAggregator extends AbstractTDigestPercentilesAggregator {
 
     TDigestPercentileRanksAggregator(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregator.java
index 4c9213f35d10c..a5844858d29c4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregator.java
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a single TDigest Percentile
+ *
+ * @opensearch.internal
+ */
 class TDigestPercentilesAggregator extends AbstractTDigestPercentilesAggregator {
 
     TDigestPercentilesAggregator(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestState.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestState.java
index c6ea32d6e9620..b61bbcfe1cbbf 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestState.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TDigestState.java
@@ -31,16 +31,19 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.tdunning.math.stats.AVLTreeDigest;
-import com.tdunning.math.stats.Centroid;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 import java.util.Iterator;
 
+import com.tdunning.math.stats.AVLTreeDigest;
+import com.tdunning.math.stats.Centroid;
+
 /**
  * Extension of {@link com.tdunning.math.stats.TDigest} with custom serialization.
+ *
+ * @opensearch.internal
  */
 public class TDigestState extends AVLTreeDigest {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHits.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHits.java
index dc6b02636d627..101af7daafad6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHits.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHits.java
@@ -36,6 +36,8 @@
 
 /**
  * Accumulation of the most relevant hits for a bucket this aggregation falls into.
+ *
+ * @opensearch.internal
  */
 public interface TopHits extends Aggregation {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregationBuilder.java
index d1097aaa20612..c6e9b629d09ac 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregationBuilder.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.FieldScript;
@@ -72,6 +72,11 @@
 import java.util.Optional;
 import java.util.Set;
 
+/**
+ * Aggregation Builder for top_hits agg
+ *
+ * @opensearch.internal
+ */
 public class TopHitsAggregationBuilder extends AbstractAggregationBuilder<TopHitsAggregationBuilder> {
     public static final String NAME = "top_hits";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregator.java
index 94425501de3e2..2d78360f20bc6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregator.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.LongObjectHashMap;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.FieldDoc;
@@ -68,10 +66,21 @@
 import org.opensearch.search.sort.SortAndFormats;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into the top hits
+ *
+ * @opensearch.internal
+ */
 class TopHitsAggregator extends MetricsAggregator {
 
+    /**
+     * Collectors for top hits
+     *
+     * @opensearch.internal
+     */
     private static class Collectors {
         public final TopDocsCollector<?> topDocsCollector;
         public final MaxScoreCollector maxScoreCollector;
@@ -119,7 +128,7 @@ public LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCol
         // when post collecting then we have already replaced the leaf readers on the aggregator level have already been
         // replaced with the next leaf readers and then post collection pushes docids of the previous segment, which
         // then causes assertions to trip or incorrect top docs to be computed.
-        final LongObjectHashMap<LeafCollector> leafCollectors = new LongObjectHashMap<>(1);
+        final Map<Long, LeafCollector> leafCollectors = new HashMap<>(1);
         return new LeafBucketCollectorBase(sub, null) {
 
             Scorable scorer;
@@ -128,8 +137,8 @@ public LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCol
             public void setScorer(Scorable scorer) throws IOException {
                 this.scorer = scorer;
                 super.setScorer(scorer);
-                for (ObjectCursor<LeafCollector> cursor : leafCollectors.values()) {
-                    cursor.value.setScorer(scorer);
+                for (var collector : leafCollectors.values()) {
+                    collector.setScorer(scorer);
                 }
             }
 
@@ -160,16 +169,13 @@ public void collect(int docId, long bucket) throws IOException {
                     topDocsCollectors.put(bucket, collectors);
                 }
 
-                final LeafCollector leafCollector;
-                final int key = leafCollectors.indexOf(bucket);
-                if (key < 0) {
+                LeafCollector leafCollector = leafCollectors.get(bucket);
+                if (leafCollector == null) {
                     leafCollector = collectors.collector.getLeafCollector(ctx);
                     if (scorer != null) {
                         leafCollector.setScorer(scorer);
                     }
-                    leafCollectors.indexInsert(key, bucket, leafCollector);
-                } else {
-                    leafCollector = leafCollectors.indexGet(key);
+                    leafCollectors.put(bucket, leafCollector);
                 }
                 leafCollector.collect(docId);
             }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorFactory.java
index b9699964a611e..ba371327c6893 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorFactory.java
@@ -53,6 +53,11 @@
 import java.util.Map;
 import java.util.Optional;
 
+/**
+ * Aggregation Factory for top_hits agg
+ *
+ * @opensearch.internal
+ */
 class TopHitsAggregatorFactory extends AggregatorFactory {
 
     private final int from;
@@ -150,4 +155,8 @@ public Aggregator createInternal(
         return new TopHitsAggregator(searchContext.fetchPhase(), subSearchContext, name, searchContext, parent, metadata);
     }
 
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCount.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCount.java
index 158c29eca4cbc..8c35a6a7ac72e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCount.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCount.java
@@ -34,6 +34,8 @@
 /**
  * An get that holds the number of <strong>values</strong> that the current document set has for a specific
  * field.
+ *
+ * @opensearch.internal
  */
 public interface ValueCount extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregationBuilder.java
index 246609f518547..0258a2c87cb20 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregationBuilder.java
@@ -33,10 +33,10 @@
 package org.opensearch.search.aggregations.metrics;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorFactories;
@@ -51,6 +51,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for value_count agg
+ *
+ * @opensearch.internal
+ */
 public class ValueCountAggregationBuilder extends ValuesSourceAggregationBuilder.LeafOnly<ValuesSource, ValueCountAggregationBuilder> {
     public static final String NAME = "value_count";
     public static final ValuesSourceRegistry.RegistryKey<MetricAggregatorSupplier> REGISTRY_KEY = new ValuesSourceRegistry.RegistryKey<>(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregator.java
index 4ba2245e9779e..be98df384fc28 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregator.java
@@ -55,6 +55,8 @@
  *
  * This aggregator works in a multi-bucket mode, that is, when serves as a sub-aggregator, a single aggregator instance aggregates the
  * counts for all buckets owned by the parent aggregator)
+ *
+ * @opensearch.internal
  */
 public class ValueCountAggregator extends NumericMetricsAggregator.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorFactory.java
index 1542f25dd49c2..4a04dd2e0a932 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorFactory.java
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Factory for value_count agg
+ *
+ * @opensearch.internal
+ */
 class ValueCountAggregatorFactory extends ValuesSourceAggregatorFactory {
 
     public static void registerAggregators(ValuesSourceRegistry.Builder builder) {
@@ -79,4 +84,9 @@ protected Aggregator doCreateInternal(
             .getAggregator(ValueCountAggregationBuilder.REGISTRY_KEY, config)
             .build(name, config, searchContext, parent, metadata);
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvg.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvg.java
index 8afd013f7306e..b81520f8790ca 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvg.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvg.java
@@ -33,6 +33,8 @@
 
 /**
  * An aggregation that computes the average of the values in the current bucket.
+ *
+ * @opensearch.internal
  */
 public interface WeightedAvg extends NumericMetricsAggregation.SingleValue {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregationBuilder.java
index 6afad18ddd282..019be14f7ae82 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
@@ -58,6 +58,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for weighted_avg agg
+ *
+ * @opensearch.internal
+ */
 public class WeightedAvgAggregationBuilder extends MultiValuesSourceAggregationBuilder.LeafOnly<WeightedAvgAggregationBuilder> {
     public static final String NAME = "weighted_avg";
     public static final ParseField VALUE_FIELD = new ParseField("value");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregator.java
index 6498674e83847..d85ee651cb5e0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregator.java
@@ -52,6 +52,11 @@
 import static org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder.VALUE_FIELD;
 import static org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder.WEIGHT_FIELD;
 
+/**
+ * Aggregate all docs into a weighted average
+ *
+ * @opensearch.internal
+ */
 class WeightedAvgAggregator extends NumericMetricsAggregator.SingleValue {
 
     private final MultiValuesSource.NumericMultiValuesSource valuesSources;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorFactory.java
index add0933d40066..111245cae99e5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorFactory.java
@@ -48,6 +48,11 @@
 
 import static org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder.VALUE_FIELD;
 
+/**
+ * Aggregation Factory for weighted_avg agg
+ *
+ * @opensearch.internal
+ */
 class WeightedAvgAggregatorFactory extends MultiValuesSourceAggregatorFactory {
 
     WeightedAvgAggregatorFactory(
@@ -90,4 +95,9 @@ protected Aggregator doCreateInternal(
     public String getStatsSubtype() {
         return configs.get(VALUE_FIELD.getPreferredName()).valueSourceType().typeName();
     }
+
+    @Override
+    protected boolean supportsConcurrentSegmentSearch() {
+        return true;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AbstractPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AbstractPipelineAggregationBuilder.java
index 290e13b2ee4bc..49e8abd46bf5c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AbstractPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AbstractPipelineAggregationBuilder.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.PipelineAggregationBuilder;
 
 import java.io.IOException;
@@ -44,6 +44,8 @@
 
 /**
  * Base implementation of a {@link PipelineAggregationBuilder}.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractPipelineAggregationBuilder<PAB extends AbstractPipelineAggregationBuilder<PAB>> extends
     PipelineAggregationBuilder {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregationBuilder.java
index 619d7aa5d4407..d712582c8d96b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregationBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for avg_bucket agg
+ *
+ * @opensearch.internal
+ */
 public class AvgBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<AvgBucketPipelineAggregationBuilder> {
     public static final String NAME = "avg_bucket";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregator.java
index 5aea6e1893c04..4939741ef8d85 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/AvgBucketPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into an average bucket
+ *
+ * @opensearch.internal
+ */
 public class AvgBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private int count = 0;
     private double sum = 0;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketHelpers.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketHelpers.java
index d73b7a2330041..3015e7ce9f364 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketHelpers.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketHelpers.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentLocation;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentLocation;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
 import org.opensearch.search.aggregations.InvalidAggregationPathException;
@@ -54,6 +54,8 @@
 /**
  * A set of static helpers to simplify working with aggregation buckets, in
  * particular providing utilities that help pipeline aggregations.
+ *
+ * @opensearch.internal
  */
 public class BucketHelpers {
 
@@ -65,6 +67,8 @@ public class BucketHelpers {
      *
      * "insert_zeros": empty buckets will be filled with zeros for all metrics
      * "skip": empty buckets will simply be ignored
+     *
+     * @opensearch.internal
      */
     public enum GapPolicy implements Writeable {
         INSERT_ZEROS((byte) 0, "insert_zeros"),
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricValue.java
index 04335c2200e5b..bada4fedceca4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricValue.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.search.aggregations.metrics.NumericMetricsAggregation;
 
+/**
+ * Base class of a metric value for a bucket
+ *
+ * @opensearch.internal
+ */
 public interface BucketMetricValue extends NumericMetricsAggregation.SingleValue {
 
     String[] keys();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsParser.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsParser.java
index b6c78f63687e3..2e7bbd703b9d8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsParser.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsParser.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 
 import java.io.IOException;
@@ -45,6 +45,8 @@
 
 /**
  * A parser for parsing requests for a {@link BucketMetricsPipelineAggregator}
+ *
+ * @opensearch.internal
  */
 public abstract class BucketMetricsParser implements PipelineAggregator.Parser {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregationBuilder.java
index 239a8e61595a3..d156e5aa05e73 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregationBuilder.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -44,6 +44,11 @@
 import java.util.Objects;
 import java.util.Optional;
 
+/**
+ * Base Aggregation Builder for bucket metrics pipeline aggs
+ *
+ * @opensearch.internal
+ */
 public abstract class BucketMetricsPipelineAggregationBuilder<AF extends BucketMetricsPipelineAggregationBuilder<AF>> extends
     AbstractPipelineAggregationBuilder<AF> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregator.java
index 5f690725b29ff..804426acd5721 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketMetricsPipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.Aggregations;
@@ -50,6 +50,8 @@
 /**
  * A class of sibling pipeline aggregations which calculate metrics across the
  * buckets of a sibling aggregation
+ *
+ * @opensearch.internal
  */
 public abstract class BucketMetricsPipelineAggregator extends SiblingPipelineAggregator {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregationBuilder.java
index 9c633ddfa4093..76516bd5d8f98 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -51,11 +51,16 @@
 import java.util.Objects;
 import java.util.TreeMap;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
 
+/**
+ * Aggregation Builder for bucket_script agg
+ *
+ * @opensearch.internal
+ */
 public class BucketScriptPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<BucketScriptPipelineAggregationBuilder> {
     public static final String NAME = "bucket_script";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregator.java
index 3c100bae08a95..a903a89ea97fa 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketScriptPipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.script.BucketAggregationScript;
 import org.opensearch.script.Script;
 import org.opensearch.search.DocValueFormat;
@@ -53,6 +53,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a bucket defined by a script
+ *
+ * @opensearch.internal
+ */
 public class BucketScriptPipelineAggregator extends PipelineAggregator {
     private final DocValueFormat formatter;
     private final GapPolicy gapPolicy;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java
index b2887ffc7e7a4..c9d1e474fafa8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 
@@ -51,6 +51,11 @@
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
 
+/**
+ * Aggregation Builder for bucket_selector agg
+ *
+ * @opensearch.internal
+ */
 public class BucketSelectorPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<BucketSelectorPipelineAggregationBuilder> {
     public static final String NAME = "bucket_selector";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregator.java
index 316dee93f1c55..dc10aa008a036 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSelectorPipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.script.BucketAggregationSelectorScript;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -49,6 +49,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a selected bucket
+ *
+ * @opensearch.internal
+ */
 public class BucketSelectorPipelineAggregator extends PipelineAggregator {
     private GapPolicy gapPolicy;
     private Script script;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregationBuilder.java
index cc780829bf99e..70ac8b326f523 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregationBuilder.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.sort.FieldSortBuilder;
@@ -52,7 +52,7 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
 
 /**
@@ -60,6 +60,8 @@
  * aggregation. The bucket {@code _key}, {@code _count} or sub-aggregations may be used as sort
  * keys. Parameters {@code from} and {@code size} may also be set in order to truncate the
  * result bucket list.
+ *
+ * @opensearch.internal
  */
 public class BucketSortPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<BucketSortPipelineAggregationBuilder> {
     public static final String NAME = "bucket_sort";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregator.java
index 77058809e719e..887b3a9afbadb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/BucketSortPipelineAggregator.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
@@ -48,6 +48,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into sorted buckets
+ *
+ * @opensearch.internal
+ */
 public class BucketSortPipelineAggregator extends PipelineAggregator {
 
     private final List<FieldSortBuilder> sorts;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregationBuilder.java
index fd31bbc6d4abc..5ec5bdffe0ce9 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregationBuilder.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
@@ -43,9 +43,14 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 
+/**
+ * Aggregation Builder for cumulative_sum pipeline agg
+ *
+ * @opensearch.internal
+ */
 public class CumulativeSumPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<CumulativeSumPipelineAggregationBuilder> {
     public static final String NAME = "cumulative_sum";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregator.java
index 0903fbf858160..a7f0bf8ca25c5 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/CumulativeSumPipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
@@ -52,6 +52,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a cumulative sum bucket
+ *
+ * @opensearch.internal
+ */
 public class CumulativeSumPipelineAggregator extends PipelineAggregator {
     private final DocValueFormat formatter;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/Derivative.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/Derivative.java
index bbe87f5c27d2d..eb92a78f716dd 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/Derivative.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/Derivative.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
+/**
+ * Base class of a derivitive
+ *
+ * @opensearch.internal
+ */
 public interface Derivative extends SimpleValue {
 
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregationBuilder.java
index b5d6f3d20663c..8a4fed691ee98 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregationBuilder.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.Rounding;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for derivative agg
+ *
+ * @opensearch.internal
+ */
 public class DerivativePipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<DerivativePipelineAggregationBuilder> {
     public static final String NAME = "derivative";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregator.java
index 6312b479e32f1..c16f68b5273d1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/DerivativePipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
@@ -52,6 +52,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a derivative value
+ *
+ * @opensearch.internal
+ */
 public class DerivativePipelineAggregator extends PipelineAggregator {
     private final DocValueFormat formatter;
     private final GapPolicy gapPolicy;
@@ -115,9 +120,9 @@ public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext
                 if (xAxisUnits != null) {
                     xDiff = (thisBucketKey.doubleValue() - lastBucketKey.doubleValue()) / xAxisUnits;
                 }
-                final List<InternalAggregation> aggs = StreamSupport.stream(bucket.getAggregations().spliterator(), false)
-                    .map((p) -> { return (InternalAggregation) p; })
-                    .collect(Collectors.toList());
+                final List<InternalAggregation> aggs = StreamSupport.stream(bucket.getAggregations().spliterator(), false).map((p) -> {
+                    return (InternalAggregation) p;
+                }).collect(Collectors.toList());
                 aggs.add(new InternalDerivative(name(), gradient, xDiff, formatter, metadata()));
                 Bucket newBucket = factory.createBucket(factory.getKey(bucket), bucket.getDocCount(), InternalAggregations.from(aggs));
                 newBuckets.add(newBucket);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/EwmaModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/EwmaModel.java
index 6545db9117e2d..a63eba9355a6d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/EwmaModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/EwmaModel.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -46,6 +46,8 @@
 
 /**
  * Calculate a exponentially weighted moving average
+ *
+ * @opensearch.internal
  */
 public class EwmaModel extends MovAvgModel {
     public static final String NAME = "ewma";
@@ -151,6 +153,11 @@ public boolean equals(Object obj) {
         return Objects.equals(alpha, other.alpha);
     }
 
+    /**
+     * Builder for the EWMA model
+     *
+     * @opensearch.internal
+     */
     public static class EWMAModelBuilder implements MovAvgModelBuilder {
 
         private double alpha = DEFAULT_ALPHA;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucket.java
index 253901a40d01b..1e74c18e5f82f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucket.java
@@ -36,5 +36,7 @@
 
 /**
  * Extended Statistics over a set of buckets
+ *
+ * @opensearch.internal
  */
 public interface ExtendedStatsBucket extends ExtendedStats {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketParser.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketParser.java
index d9f7765dc515e..5083c78feca3e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketParser.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketParser.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Parses extended stats values
+ *
+ * @opensearch.internal
+ */
 public class ExtendedStatsBucketParser extends BucketMetricsParser {
     static final ParseField SIGMA = new ParseField("sigma");
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregationBuilder.java
index 1c44a7c7c1caf..165253379f146 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregationBuilder.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for extended_stats agg
+ *
+ * @opensearch.internal
+ */
 public class ExtendedStatsBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<
     ExtendedStatsBucketPipelineAggregationBuilder> {
     public static final String NAME = "extended_stats_bucket";
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregator.java
index 0c6121217dce5..ce55521684008 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketPipelineAggregator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into their extended stats
+ *
+ * @opensearch.internal
+ */
 public class ExtendedStatsBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private final double sigma;
     private double sum = 0;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltLinearModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltLinearModel.java
index 51ed0466d0b33..6ac075c5714d6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltLinearModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltLinearModel.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -45,6 +45,8 @@
 
 /**
  * Calculate a doubly exponential weighted moving average
+ *
+ * @opensearch.internal
  */
 public class HoltLinearModel extends MovAvgModel {
     public static final String NAME = "holt";
@@ -193,6 +195,11 @@ public boolean equals(Object obj) {
         return Objects.equals(alpha, other.alpha) && Objects.equals(beta, other.beta);
     }
 
+    /**
+     * Builder for the holt linear model
+     *
+     * @opensearch.internal
+     */
     public static class HoltLinearModelBuilder implements MovAvgModelBuilder {
         private double alpha = DEFAULT_ALPHA;
         private double beta = DEFAULT_BETA;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltWintersModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltWintersModel.java
index 474c91573c528..fa0f889a967f4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltWintersModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/HoltWintersModel.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -50,6 +50,8 @@
 
 /**
  * Calculate a triple exponential weighted moving average
+ *
+ * @opensearch.internal
  */
 public class HoltWintersModel extends MovAvgModel {
     public static final String NAME = "holt_winters";
@@ -61,6 +63,11 @@ public class HoltWintersModel extends MovAvgModel {
     private static final SeasonalityType DEFAULT_SEASONALITY_TYPE = SeasonalityType.ADDITIVE;
     private static final boolean DEFAULT_PAD = false;
 
+    /**
+     * The seasonality type
+     *
+     * @opensearch.internal
+     */
     public enum SeasonalityType {
         ADDITIVE((byte) 0, "add"),
         MULTIPLICATIVE((byte) 1, "mult");
@@ -390,6 +397,11 @@ public boolean equals(Object obj) {
             && Objects.equals(pad, other.pad);
     }
 
+    /**
+     * Builder for the holt winters model
+     *
+     * @opensearch.internal
+     */
     public static class HoltWintersModelBuilder implements MovAvgModelBuilder {
 
         private double alpha = DEFAULT_ALPHA;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalBucketMetricValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalBucketMetricValue.java
index 4e0566250ebd2..40ecb6830b9f4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalBucketMetricValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalBucketMetricValue.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
@@ -46,6 +46,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of a bucket metric value
+ *
+ * @opensearch.internal
+ */
 public class InternalBucketMetricValue extends InternalNumericMetricsAggregation.SingleValue implements BucketMetricValue {
     public static final String NAME = "bucket_metric_value";
     static final ParseField KEYS_FIELD = new ParseField("keys");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalDerivative.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalDerivative.java
index 81fcbe091768d..090543d0bbb9d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalDerivative.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalDerivative.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
@@ -42,6 +42,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of derivitive pipeline
+ *
+ * @opensearch.internal
+ */
 public class InternalDerivative extends InternalSimpleValue implements Derivative {
     private final double normalizationFactor;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalExtendedStatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalExtendedStatsBucket.java
index b01b7be6a9c80..5c8a77e9c760a 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalExtendedStatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalExtendedStatsBucket.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.metrics.InternalExtendedStats;
@@ -41,6 +41,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Implementation of extended stats pipeline
+ *
+ * @opensearch.internal
+ */
 public class InternalExtendedStatsBucket extends InternalExtendedStats implements ExtendedStatsBucket {
     InternalExtendedStatsBucket(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucket.java
index 4603d68325513..e24345a321b91 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucket.java
@@ -33,13 +33,13 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
-import org.opensearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
 import org.opensearch.search.aggregations.metrics.InternalMax;
+import org.opensearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
 import org.opensearch.search.aggregations.metrics.Percentile;
 
 import java.io.IOException;
@@ -50,6 +50,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of percentiles pipeline
+ *
+ * @opensearch.internal
+ */
 public class InternalPercentilesBucket extends InternalNumericMetricsAggregation.MultiValue implements PercentilesBucket {
     private double[] percentiles;
     private double[] percents;
@@ -204,6 +209,11 @@ public int hashCode() {
         return Objects.hash(super.hashCode(), Arrays.hashCode(percents), Arrays.hashCode(percentiles));
     }
 
+    /**
+     * Iterator for the percentiles agg
+     *
+     * @opensearch.internal
+     */
     public static class Iter implements Iterator<Percentile> {
 
         private final double[] percents;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalSimpleValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalSimpleValue.java
index e3f505e52b2a2..c6b1ea0e1c1e7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalSimpleValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalSimpleValue.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
@@ -44,6 +44,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Implementation of simple value pipeline
+ *
+ * @opensearch.internal
+ */
 public class InternalSimpleValue extends InternalNumericMetricsAggregation.SingleValue implements SimpleValue {
     public static final String NAME = "simple_value";
     protected final double value;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalStatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalStatsBucket.java
index 44916c80cab7e..cee433aeaab41 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalStatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/InternalStatsBucket.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.metrics.InternalStats;
@@ -41,6 +41,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Implementation of stats pipeline
+ *
+ * @opensearch.internal
+ */
 public class InternalStatsBucket extends InternalStats implements StatsBucket {
     public InternalStatsBucket(
         String name,
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/LinearModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/LinearModel.java
index 0e1ffdbedcfa8..9035beecc1d6d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/LinearModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/LinearModel.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -46,6 +46,8 @@
 /**
  * Calculate a linearly weighted moving average, such that older values are
  * linearly less important.  "Time" is determined by position in collection
+ *
+ * @opensearch.internal
  */
 public class LinearModel extends MovAvgModel {
     public static final String NAME = "linear";
@@ -111,6 +113,11 @@ public MovAvgModel parse(@Nullable Map<String, Object> settings, String pipeline
         }
     };
 
+    /**
+     * Builder for the linear model
+     *
+     * @opensearch.internal
+     */
     public static class LinearModelBuilder implements MovAvgModelBuilder {
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregationBuilder.java
index 854ea18021bf6..0b3172c74e1de 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregationBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for max_bucket agg
+ *
+ * @opensearch.internal
+ */
 public class MaxBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<MaxBucketPipelineAggregationBuilder> {
     public static final String NAME = "max_bucket";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregator.java
index 03bf1c78a8220..ba8d3878eda48 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MaxBucketPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -42,6 +42,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a max bucket
+ *
+ * @opensearch.internal
+ */
 public class MaxBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private List<String> maxBucketKeys;
     private double maxValue;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregationBuilder.java
index 96ab48b01c115..eb9ffb2e488ae 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregationBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for min_bucket
+ *
+ * @opensearch.internal
+ */
 public class MinBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<MinBucketPipelineAggregationBuilder> {
     public static final String NAME = "min_bucket";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregator.java
index 137aac02b83cf..909d6ee0d0909 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MinBucketPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -42,6 +42,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a min bucket
+ *
+ * @opensearch.internal
+ */
 public class MinBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private List<String> minBucketKeys;
     private double minValue;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModel.java
index b63fee917ce9e..ab415943ee676 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModel.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -43,6 +43,11 @@
 import java.util.Collection;
 import java.util.Map;
 
+/**
+ * Base moving average model class
+ *
+ * @opensearch.internal
+ */
 public abstract class MovAvgModel implements NamedWriteable, ToXContentFragment {
 
     /**
@@ -153,6 +158,8 @@ protected double[] emptyPredictions(int numPredictions) {
 
     /**
      * Abstract class which also provides some concrete parsing functionality.
+     *
+     * @opensearch.internal
      */
     public abstract static class AbstractModelParser {
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModelBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModelBuilder.java
index c369a127c164c..f63a64be87b5d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModelBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgModelBuilder.java
@@ -32,11 +32,13 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentFragment;
 
 /**
  * Represents the common interface that all moving average models share. Moving
  * average models are used by the MovAvg aggregation
+ *
+ * @opensearch.internal
  */
 public interface MovAvgModelBuilder extends ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregationBuilder.java
index 298720785f461..e53ac003712ea 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregationBuilder.java
@@ -32,9 +32,16 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
-import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
-import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
+import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.common.xcontent.ParseFieldRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -43,17 +50,15 @@
 import java.util.Map;
 import java.util.Objects;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.logging.DeprecationLogger;
-import org.opensearch.common.xcontent.ParseFieldRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.search.DocValueFormat;
-import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
+import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
+import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
+import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
 
+/**
+ * Aggregation Builder for moving_avg
+ *
+ * @opensearch.internal
+ */
 public class MovAvgPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<MovAvgPipelineAggregationBuilder> {
     public static final String NAME = "moving_avg";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregator.java
index d4ce4170e10b4..e306735fb4917 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovAvgPipelineAggregator.java
@@ -33,8 +33,8 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.collect.EvictingQueue;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
@@ -55,6 +55,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a moving average bucket
+ *
+ * @opensearch.internal
+ */
 public class MovAvgPipelineAggregator extends PipelineAggregator {
     private final DocValueFormat formatter;
     private final GapPolicy gapPolicy;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregationBuilder.java
index 56f7ab0c33336..bda6bdfe43bbc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregationBuilder.java
@@ -33,14 +33,14 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -50,11 +50,16 @@
 import java.util.Map;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.GAP_POLICY;
 
+/**
+ * Aggregation Builder for moving_fn
+ *
+ * @opensearch.internal
+ */
 public class MovFnPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<MovFnPipelineAggregationBuilder> {
     public static final String NAME = "moving_fn";
     private static final ParseField WINDOW = new ParseField("window");
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregator.java
index 7f1bb8965ed94..aaeddbfde3eb0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovFnPipelineAggregator.java
@@ -33,8 +33,8 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.script.Script;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -69,6 +69,8 @@
  *  - holtWintersMovAvg
  *
  *  The user can also define any arbitrary logic via their own scripting, or combine with the above methods.
+ *
+ * @opensearch.internal
  */
 public class MovFnPipelineAggregator extends PipelineAggregator {
     private final DocValueFormat formatter;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctionScript.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctionScript.java
index 23fcd8b25b342..20dd463a3cca7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctionScript.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctionScript.java
@@ -40,6 +40,8 @@
 /**
  * This class provides a custom script context for the Moving Function pipeline aggregation,
  * so that we can expose a number of pre-baked moving functions like min, max, movavg, etc
+ *
+ * @opensearch.internal
  */
 public abstract class MovingFunctionScript {
     /**
@@ -49,6 +51,11 @@ public abstract class MovingFunctionScript {
      */
     public abstract double execute(Map<String, Object> params, double[] values);
 
+    /**
+     * Factory interface
+     *
+     * @opensearch.internal
+     */
     public interface Factory extends ScriptFactory {
         MovingFunctionScript newInstance();
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctions.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctions.java
index e3a57654f94cf..bac486576f537 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctions.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/MovingFunctions.java
@@ -36,6 +36,8 @@
 
 /**
  * Provides a collection of static utility methods that can be referenced from MovingFunction script contexts
+ *
+ * @opensearch.internal
  */
 public class MovingFunctions {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedBucketMetricValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedBucketMetricValue.java
index 7ecbd64d9cff4..5d4206e49735f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedBucketMetricValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedBucketMetricValue.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.ParsedSingleValueNumericMetricsAggregation;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * A bucket metric agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedBucketMetricValue extends ParsedSingleValueNumericMetricsAggregation implements BucketMetricValue {
 
     private List<String> keys = Collections.emptyList();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedDerivative.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedDerivative.java
index 0ce2c121f0658..c1f3c3d76d36e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedDerivative.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedDerivative.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A derivative agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedDerivative extends ParsedSimpleValue implements Derivative {
 
     private double normalizedValue;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedExtendedStatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedExtendedStatsBucket.java
index 0a518a8363ab6..18a5d19b9c0da 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedExtendedStatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedExtendedStatsBucket.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.ParsedExtendedStats;
 
+/**
+ * An extended stats agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedExtendedStatsBucket extends ParsedExtendedStats implements ExtendedStatsBucket {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedPercentilesBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedPercentilesBucket.java
index fe274862c0698..e1fbb1336eb76 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedPercentilesBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedPercentilesBucket.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.ParsedPercentiles;
 import org.opensearch.search.aggregations.metrics.Percentiles;
 
 import java.io.IOException;
 import java.util.Map.Entry;
 
+/**
+ * A percentiles bucket agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedPercentilesBucket extends ParsedPercentiles implements Percentiles {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedSimpleValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedSimpleValue.java
index 30cffd8fdf48a..4c664713d26f7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedSimpleValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedSimpleValue.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.ParsedSingleValueNumericMetricsAggregation;
 
 import java.io.IOException;
 
+/**
+ * A simple value agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedSimpleValue extends ParsedSingleValueNumericMetricsAggregation implements SimpleValue {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedStatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedStatsBucket.java
index fc20befbd5c1b..141999a25c2af 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedStatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/ParsedStatsBucket.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.metrics.ParsedStats;
 
+/**
+ * A stats agg result parsed between nodes
+ *
+ * @opensearch.internal
+ */
 public class ParsedStatsBucket extends ParsedStats implements StatsBucket {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucket.java
index e335dbbaa3ddb..fadc32192a6fb 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucket.java
@@ -34,4 +34,9 @@
 
 import org.opensearch.search.aggregations.metrics.Percentiles;
 
+/**
+ * Base noop bucket implementation for percentiles
+ *
+ * @opensearch.internal
+ */
 public interface PercentilesBucket extends Percentiles {}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregationBuilder.java
index 01d30185917f1..b5f75350c1f1c 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregationBuilder.java
@@ -32,20 +32,25 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import com.carrotsearch.hppc.DoubleArrayList;
-
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Aggregation Builder for percentiles_bucket
+ *
+ * @opensearch.internal
+ */
 public class PercentilesBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<
     PercentilesBucketPipelineAggregationBuilder> {
     public static final String NAME = "percentiles_bucket";
@@ -177,11 +182,11 @@ protected PercentilesBucketPipelineAggregationBuilder buildFactory(
         protected boolean token(XContentParser parser, String field, XContentParser.Token token, Map<String, Object> params)
             throws IOException {
             if (PERCENTS_FIELD.match(field, parser.getDeprecationHandler()) && token == XContentParser.Token.START_ARRAY) {
-                DoubleArrayList percents = new DoubleArrayList(10);
+                final List<Double> percents = new ArrayList<>(10);
                 while (parser.nextToken() != XContentParser.Token.END_ARRAY) {
                     percents.add(parser.doubleValue());
                 }
-                params.put(PERCENTS_FIELD.getPreferredName(), percents.toArray());
+                params.put(PERCENTS_FIELD.getPreferredName(), percents.stream().mapToDouble(Double::doubleValue).toArray());
                 return true;
             } else if (KEYED_FIELD.match(field, parser.getDeprecationHandler()) && token == XContentParser.Token.VALUE_BOOLEAN) {
                 params.put(KEYED_FIELD.getPreferredName(), parser.booleanValue());
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregator.java
index 02cb75b37c6a7..7c31dc7c07e5b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketPipelineAggregator.java
@@ -33,8 +33,8 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -45,6 +45,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a percentiles bucket
+ *
+ * @opensearch.internal
+ */
 public class PercentilesBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
 
     private final double[] percents;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PipelineAggregator.java
index ae0a81f27bfd1..2972be6865126 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/PipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/PipelineAggregator.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
 import org.opensearch.search.aggregations.PipelineAggregationBuilder;
@@ -49,9 +49,16 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 
+/**
+ * Base aggregator for pipline aggs
+ *
+ * @opensearch.internal
+ */
 public abstract class PipelineAggregator implements NamedWriteable {
     /**
      * Parse the {@link PipelineAggregationBuilder} from a {@link XContentParser}.
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface Parser {
@@ -76,6 +83,8 @@ public interface Parser {
     /**
      * Tree of {@link PipelineAggregator}s to modify a tree of aggregations
      * after their final reduction.
+     *
+     * @opensearch.internal
      */
     public static class PipelineTree {
         /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregationBuilder.java
index 2b07442b80719..628ac1bbfb16d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 
@@ -50,6 +50,11 @@
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.BUCKETS_PATH;
 import static org.opensearch.search.aggregations.pipeline.PipelineAggregator.Parser.FORMAT;
 
+/**
+ * Aggregation Builder for serial_diff agg
+ *
+ * @opensearch.internal
+ */
 public class SerialDiffPipelineAggregationBuilder extends AbstractPipelineAggregationBuilder<SerialDiffPipelineAggregationBuilder> {
     public static final String NAME = "serial_diff";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregator.java
index eea9f76d5d091..4627185d3dcd7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SerialDiffPipelineAggregator.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.common.Nullable;
 import org.opensearch.common.collect.EvictingQueue;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
@@ -54,6 +54,11 @@
 
 import static org.opensearch.search.aggregations.pipeline.BucketHelpers.resolveBucketValue;
 
+/**
+ * Aggregate all docs into a serial diff bucket
+ *
+ * @opensearch.internal
+ */
 public class SerialDiffPipelineAggregator extends PipelineAggregator {
     private DocValueFormat formatter;
     private GapPolicy gapPolicy;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SiblingPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SiblingPipelineAggregator.java
index 2375b75d30af1..cf8fa3504710b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SiblingPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SiblingPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
@@ -42,6 +42,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a sibling bucket
+ *
+ * @opensearch.internal
+ */
 public abstract class SiblingPipelineAggregator extends PipelineAggregator {
     protected SiblingPipelineAggregator(String name, String[] bucketsPaths, Map<String, Object> metadata) {
         super(name, bucketsPaths, metadata);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleModel.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleModel.java
index b133308b61ed5..290f164d5a8db 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleModel.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleModel.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.aggregations.pipeline;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -45,6 +45,8 @@
 
 /**
  * Calculate a simple unweighted (arithmetic) moving average
+ *
+ * @opensearch.internal
  */
 public class SimpleModel extends MovAvgModel {
     public static final String NAME = "simple";
@@ -110,6 +112,11 @@ public MovAvgModel parse(@Nullable Map<String, Object> settings, String pipeline
         }
     };
 
+    /**
+     * Builder for the simple model
+     *
+     * @opensearch.internal
+     */
     public static class SimpleModelBuilder implements MovAvgModelBuilder {
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleValue.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleValue.java
index 4e3a7b65eb9b8..f062164adab8e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleValue.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimpleValue.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.search.aggregations.metrics.NumericMetricsAggregation;
 
+/**
+ * Base noop class for simple values
+ *
+ * @opensearch.internal
+ */
 public interface SimpleValue extends NumericMetricsAggregation.SingleValue {
 
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimulatedAnealingMinimizer.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimulatedAnealingMinimizer.java
index 19d06cec15f72..a61a866228161 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimulatedAnealingMinimizer.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SimulatedAnealingMinimizer.java
@@ -46,6 +46,8 @@
  * anyway.  This allows the algo to sample the problem space widely.  As iterations progress,
  * the temperature decreases and the algorithm rejects poor solutions more regularly,
  * theoretically honing in on a global minimum.
+ *
+ * @opensearch.internal
  */
 public class SimulatedAnealingMinimizer {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucket.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucket.java
index e846a7a90d6b5..6995307503256 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucket.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucket.java
@@ -36,6 +36,8 @@
 
 /**
  * Statistics over a set of buckets
+ *
+ * @opensearch.internal
  */
 public interface StatsBucket extends Stats {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregationBuilder.java
index 1cb0f844eb7ca..cc394d85b7093 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregationBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for stats_bucket agg
+ *
+ * @opensearch.internal
+ */
 public class StatsBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<StatsBucketPipelineAggregationBuilder> {
     public static final String NAME = "stats_bucket";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregator.java
index aa0f4a645fa02..dc41a884c8be8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/StatsBucketPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a stats bucket
+ *
+ * @opensearch.internal
+ */
 public class StatsBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private double sum = 0;
     private long count = 0;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregationBuilder.java
index e7cd3ae4f2a56..2bf769780dc19 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregationBuilder.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregation Builder for sum_bucket agg
+ *
+ * @opensearch.internal
+ */
 public class SumBucketPipelineAggregationBuilder extends BucketMetricsPipelineAggregationBuilder<SumBucketPipelineAggregationBuilder> {
     public static final String NAME = "sum_bucket";
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregator.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregator.java
index baf1fdecfc3ab..79340eef5a687 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregator.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/SumBucketPipelineAggregator.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
@@ -40,6 +40,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Aggregate all docs into a sum bucket
+ *
+ * @opensearch.internal
+ */
 public class SumBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
     private double sum = 0;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/pipeline/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/pipeline/package-info.java
new file mode 100644
index 0000000000000..87172ec5f4ca6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/pipeline/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Pipeline Aggregation package. */
+package org.opensearch.search.aggregations.pipeline;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInfo.java b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInfo.java
index 47ade91638017..7d920ee2e9d56 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInfo.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInfo.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -46,6 +46,11 @@
 import java.util.TreeSet;
 import java.util.concurrent.atomic.LongAdder;
 
+/**
+ * Data describing an agg
+ *
+ * @opensearch.internal
+ */
 public class AggregationInfo implements ReportingService.Info {
 
     private final Map<String, Set<String>> aggs;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInspectionHelper.java b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInspectionHelper.java
index aca4cb8c36221..25cdd76183602 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInspectionHelper.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationInspectionHelper.java
@@ -35,12 +35,11 @@
 import org.opensearch.search.aggregations.bucket.composite.InternalComposite;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilter;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilters;
-import org.opensearch.search.aggregations.bucket.geogrid.InternalGeoGrid;
 import org.opensearch.search.aggregations.bucket.global.InternalGlobal;
-import org.opensearch.search.aggregations.bucket.histogram.InternalVariableWidthHistogram;
 import org.opensearch.search.aggregations.bucket.histogram.InternalAutoDateHistogram;
 import org.opensearch.search.aggregations.bucket.histogram.InternalDateHistogram;
 import org.opensearch.search.aggregations.bucket.histogram.InternalHistogram;
+import org.opensearch.search.aggregations.bucket.histogram.InternalVariableWidthHistogram;
 import org.opensearch.search.aggregations.bucket.missing.InternalMissing;
 import org.opensearch.search.aggregations.bucket.nested.InternalNested;
 import org.opensearch.search.aggregations.bucket.nested.InternalReverseNested;
@@ -54,7 +53,6 @@
 import org.opensearch.search.aggregations.metrics.InternalAvg;
 import org.opensearch.search.aggregations.metrics.InternalCardinality;
 import org.opensearch.search.aggregations.metrics.InternalExtendedStats;
-import org.opensearch.search.aggregations.metrics.InternalGeoBounds;
 import org.opensearch.search.aggregations.metrics.InternalGeoCentroid;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentiles;
@@ -88,6 +86,8 @@
  * or because of summing to zero).  Pipeline aggs in particular are not well supported
  * by these helpers since most share InternalSimpleValue and it's not clear which pipeline
  * generated the value.
+ *
+ * @opensearch.internal
  */
 public class AggregationInspectionHelper {
     public static <A extends InternalTerms<A, B>, B extends InternalTerms.Bucket<B>> boolean hasValue(InternalTerms<A, B> agg) {
@@ -118,10 +118,6 @@ public static boolean hasValue(InternalFilter agg) {
         return agg.getDocCount() > 0;
     }
 
-    public static boolean hasValue(InternalGeoGrid<?> agg) {
-        return agg.getBuckets().stream().anyMatch(bucket -> bucket.getDocCount() > 0);
-    }
-
     public static boolean hasValue(InternalGlobal agg) {
         return agg.getDocCount() > 0;
     }
@@ -189,10 +185,6 @@ public static boolean hasValue(InternalExtendedStats agg) {
         return agg.getCount() > 0;
     }
 
-    public static boolean hasValue(InternalGeoBounds agg) {
-        return (agg.topLeft() == null && agg.bottomRight() == null) == false;
-    }
-
     public static boolean hasValue(InternalGeoCentroid agg) {
         return agg.centroid() != null && agg.count() > 0;
     }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationPath.java b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationPath.java
index 98cd9e66d9e7e..4cfd2070211d7 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationPath.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationPath.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.aggregations.Aggregator.BucketComparator;
@@ -74,6 +74,8 @@
  *     </li>
  * </ul>
  *
+ *
+ * @opensearch.internal
  */
 public class AggregationPath {
 
@@ -126,6 +128,11 @@ public static AggregationPath parse(String path) {
         return new AggregationPath(tokens);
     }
 
+    /**
+     * Element in an agg path
+     *
+     * @opensearch.internal
+     */
     public static class PathElement {
 
         private final String fullName;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationUsageService.java b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationUsageService.java
index 8b6124cd9cc1f..7685ec5ff876f 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/AggregationUsageService.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/AggregationUsageService.java
@@ -32,18 +32,28 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.service.ReportingService;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.atomic.LongAdder;
 
+/**
+ * Service to track telemetry about aggregations
+ *
+ * @opensearch.internal
+ */
 public class AggregationUsageService implements ReportingService<AggregationInfo> {
     private final Map<String, Map<String, LongAdder>> aggs;
     private final AggregationInfo info;
 
     public static final String OTHER_SUBTYPE = "other";
 
+    /**
+     * Builder for the Agg usage service to track telemetry
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private final Map<String, Map<String, LongAdder>> aggs;
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/BaseMultiValuesSourceFieldConfig.java b/server/src/main/java/org/opensearch/search/aggregations/support/BaseMultiValuesSourceFieldConfig.java
new file mode 100644
index 0000000000000..00a27d4b936c0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/BaseMultiValuesSourceFieldConfig.java
@@ -0,0 +1,225 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.support;
+
+import org.opensearch.LegacyESVersion;
+import org.opensearch.common.TriConsumer;
+import org.opensearch.common.joda.Joda;
+import org.opensearch.common.time.DateUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.script.Script;
+
+import java.io.IOException;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.util.Objects;
+
+/**
+ * A configuration that tells aggregation how to retrieve data from index
+ * in order to run a specific aggregation.
+ *
+ * @opensearch.internal
+ */
+public abstract class BaseMultiValuesSourceFieldConfig implements Writeable, ToXContentObject {
+    private final String fieldName;
+    private final Object missing;
+    private final Script script;
+    private final ZoneId timeZone;
+
+    static TriConsumer<
+        ObjectParser<? extends Builder<? extends BaseMultiValuesSourceFieldConfig, ? extends Builder<?, ?>>, Void>,
+        Boolean,
+        Boolean> PARSER = (parser, scriptable, timezoneAware) -> {
+            parser.declareString(Builder::setFieldName, ParseField.CommonFields.FIELD);
+            parser.declareField(
+                Builder::setMissing,
+                XContentParser::objectText,
+                ParseField.CommonFields.MISSING,
+                ObjectParser.ValueType.VALUE
+            );
+
+            if (scriptable) {
+                parser.declareField(
+                    Builder::setScript,
+                    (p, context) -> Script.parse(p),
+                    Script.SCRIPT_PARSE_FIELD,
+                    ObjectParser.ValueType.OBJECT_OR_STRING
+                );
+            }
+
+            if (timezoneAware) {
+                parser.declareField(Builder::setTimeZone, p -> {
+                    if (p.currentToken() == XContentParser.Token.VALUE_STRING) {
+                        return ZoneId.of(p.text());
+                    } else {
+                        return ZoneOffset.ofHours(p.intValue());
+                    }
+                }, ParseField.CommonFields.TIME_ZONE, ObjectParser.ValueType.LONG);
+            }
+        };
+
+    public BaseMultiValuesSourceFieldConfig(String fieldName, Object missing, Script script, ZoneId timeZone) {
+        this.fieldName = fieldName;
+        this.missing = missing;
+        this.script = script;
+        this.timeZone = timeZone;
+    }
+
+    public BaseMultiValuesSourceFieldConfig(StreamInput in) throws IOException {
+        if (in.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
+            this.fieldName = in.readOptionalString();
+        } else {
+            this.fieldName = in.readString();
+        }
+        this.missing = in.readGenericValue();
+        this.script = in.readOptionalWriteable(Script::new);
+        if (in.getVersion().before(LegacyESVersion.V_7_0_0)) {
+            this.timeZone = DateUtils.dateTimeZoneToZoneId(Joda.readOptionalTimeZone(in));
+        } else {
+            this.timeZone = in.readOptionalZoneId();
+        }
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        if (out.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
+            out.writeOptionalString(fieldName);
+        } else {
+            out.writeString(fieldName);
+        }
+        out.writeGenericValue(missing);
+        out.writeOptionalWriteable(script);
+        if (out.getVersion().before(LegacyESVersion.V_7_0_0)) {
+            Joda.writeOptionalTimeZone(out, DateUtils.zoneIdToDateTimeZone(timeZone));
+        } else {
+            out.writeOptionalZoneId(timeZone);
+        }
+        doWriteTo(out);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (missing != null) {
+            builder.field(ParseField.CommonFields.MISSING.getPreferredName(), missing);
+        }
+        if (script != null) {
+            builder.field(Script.SCRIPT_PARSE_FIELD.getPreferredName(), script);
+        }
+        if (fieldName != null) {
+            builder.field(ParseField.CommonFields.FIELD.getPreferredName(), fieldName);
+        }
+        if (timeZone != null) {
+            builder.field(ParseField.CommonFields.TIME_ZONE.getPreferredName(), timeZone.getId());
+        }
+        doXContentBody(builder, params);
+        builder.endObject();
+        return builder;
+    }
+
+    public Object getMissing() {
+        return missing;
+    }
+
+    public Script getScript() {
+        return script;
+    }
+
+    public ZoneId getTimeZone() {
+        return timeZone;
+    }
+
+    public String getFieldName() {
+        return fieldName;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        BaseMultiValuesSourceFieldConfig that = (BaseMultiValuesSourceFieldConfig) o;
+        return Objects.equals(fieldName, that.fieldName)
+            && Objects.equals(missing, that.missing)
+            && Objects.equals(script, that.script)
+            && Objects.equals(timeZone, that.timeZone);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(fieldName, missing, script, timeZone);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    abstract void doXContentBody(XContentBuilder builder, Params params) throws IOException;
+
+    abstract void doWriteTo(StreamOutput out) throws IOException;
+
+    /**
+     * Base builder for the multi values source field configuration
+     *
+     * @opensearch.internal
+     */
+    public abstract static class Builder<C extends BaseMultiValuesSourceFieldConfig, B extends Builder<C, B>> {
+        String fieldName;
+        Object missing = null;
+        Script script = null;
+        ZoneId timeZone = null;
+
+        public String getFieldName() {
+            return fieldName;
+        }
+
+        public B setFieldName(String fieldName) {
+            this.fieldName = fieldName;
+            return (B) this;
+        }
+
+        public Object getMissing() {
+            return missing;
+        }
+
+        public B setMissing(Object missing) {
+            this.missing = missing;
+            return (B) this;
+        }
+
+        public Script getScript() {
+            return script;
+        }
+
+        public B setScript(Script script) {
+            this.script = script;
+            return (B) this;
+        }
+
+        public ZoneId getTimeZone() {
+            return timeZone;
+        }
+
+        public B setTimeZone(ZoneId timeZone) {
+            this.timeZone = timeZone;
+            return (B) this;
+        }
+
+        abstract public C build();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/CoreValuesSourceType.java b/server/src/main/java/org/opensearch/search/aggregations/support/CoreValuesSourceType.java
index 650b554efc1ff..224f9281705e1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/CoreValuesSourceType.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/CoreValuesSourceType.java
@@ -35,13 +35,17 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.PointValues;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Rounding;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.time.DateFormatter;
+import org.opensearch.geometry.Geometry;
+import org.opensearch.geometry.utils.WellKnownText;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexGeoPointFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
+import org.opensearch.index.fielddata.plain.AbstractGeoShapeIndexFieldData;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.DateFieldMapper.DateFieldType;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -61,6 +65,8 @@
 
 /**
  * {@link CoreValuesSourceType} holds the {@link ValuesSourceType} implementations for the core aggregations package.
+ *
+ * @opensearch.internal
  */
 public enum CoreValuesSourceType implements ValuesSourceType {
 
@@ -187,6 +193,101 @@ public DocValueFormat getFormatter(String format, ZoneId tz) {
             return DocValueFormat.GEOHASH;
         }
     },
+    GEO_SHAPE() {
+        /**
+         * Called when an aggregation is operating over a known empty set (usually because the field isn't specified), this method allows for
+         * returning a no-op implementation.  All ValuesSource should implement this method.
+         *
+         * @return - Empty specialization of the base ValuesSource
+         */
+        @Override
+        public ValuesSource getEmpty() {
+            return ValuesSource.GeoShape.EMPTY;
+        }
+
+        /**
+         * Returns the type-specific sub class for a script data source. ValuesSource that do not support scripts should throw
+         * AggregationExecutionException.  Note that this method is called when a script is
+         * operating without an underlying field.  Scripts operating over fields are handled by the script argument to getField below.
+         *
+         * @param script          - The script being wrapped
+         * @param scriptValueType - The expected output type of the script
+         * @return - Script specialization of the base ValuesSource
+         */
+        @Override
+        public ValuesSource getScript(AggregationScript.LeafFactory script, ValueType scriptValueType) {
+            throw new AggregationExecutionException(
+                String.format(Locale.ROOT, "value source of type [%s] is not supported by scripts", this.value())
+            );
+        }
+
+        /**
+         * Return a ValuesSource wrapping a field for the given type. All ValuesSource must
+         * implement this method.
+         *
+         * @param fieldContext - The field being wrapped
+         * @param script       - Optional script that might be applied over the field
+         * @return - Field specialization of the base ValuesSource
+         */
+        @Override
+        public ValuesSource getField(FieldContext fieldContext, AggregationScript.LeafFactory script) {
+            if (!(fieldContext.indexFieldData() instanceof AbstractGeoShapeIndexFieldData)) {
+                throw new IllegalArgumentException(
+                    String.format(
+                        Locale.ROOT,
+                        "Expected geo_shape type on field [%s], but got [%s]",
+                        fieldContext.field(),
+                        fieldContext.fieldType().typeName()
+                    )
+                );
+            }
+            return new ValuesSource.GeoShape.FieldData((AbstractGeoShapeIndexFieldData) fieldContext.indexFieldData());
+        }
+
+        /**
+         * Apply the given missing value to an already-constructed ValuesSource. The parameter rawMissing is
+         * the value which has been supplied by the user. We support String representation only for the
+         * rawMissing for now.
+         *
+         * @param valuesSource   - The original ValuesSource
+         * @param rawMissing     - The missing value we got from the parser, typically a string or number
+         * @param docValueFormat - The format to use for further parsing the user supplied value, e.g. a date format
+         * @param now            - Used in conjunction with the formatter, should return the current time in milliseconds
+         * @return - Wrapper over the provided ValuesSource to apply the given missing value
+         */
+        @Override
+        public ValuesSource replaceMissing(ValuesSource valuesSource, Object rawMissing, DocValueFormat docValueFormat, LongSupplier now) {
+            // TODO: also support the structured formats of geo shapes
+            try {
+                final Geometry geometry = WellKnownText.INSTANCE.fromWKT((String) rawMissing);
+                return MissingValues.replaceMissing((ValuesSource.GeoShape) valuesSource, geometry);
+            } catch (Exception e) {
+                throw new OpenSearchParseException(
+                    String.format(Locale.ROOT, "Unable to parse the missing value [%s] provided in the input.", rawMissing),
+                    e
+                );
+            }
+        }
+
+        /**
+         * This method provides a hook for specifying a type-specific formatter. When ValuesSourceConfig can resolve a
+         * MappedFieldType, it prefers to get the formatter from there. Only when a field can't be
+         * resolved (which is to say script cases and unmapped field cases), it will fall back to calling this method on whatever
+         * ValuesSourceType it was able to resolve to.
+         *
+         * For geoshape field we may never hit this function till we have aggregations which are only geo_shape
+         * specific and not present on geo_points, as we use default CoreValueSource types for Geo based aggregations
+         * as GEOPOINT
+         *
+         * @param format - User supplied format string (Optional)
+         * @param tz     - User supplied time zone (Optional)
+         * @return - A formatter object, configured with the passed in settings if appropriate.
+         */
+        @Override
+        public DocValueFormat getFormatter(String format, ZoneId tz) {
+            return DocValueFormat.RAW;
+        }
+    },
     RANGE() {
         @Override
         public ValuesSource getEmpty() {
@@ -358,6 +459,8 @@ public String typeName() {
         return value();
     }
 
+    CoreValuesSourceType() {}
+
     /** List containing all members of the enumeration. */
-    public static List<ValuesSourceType> ALL_CORE = Arrays.asList(CoreValuesSourceType.values());
+    public static final List<ValuesSourceType> ALL_CORE = Arrays.asList(CoreValuesSourceType.values());
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/FieldContext.java b/server/src/main/java/org/opensearch/search/aggregations/support/FieldContext.java
index 451afb559c0ac..a6207917d52ea 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/FieldContext.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/FieldContext.java
@@ -37,6 +37,8 @@
 /**
  * Used by all field data based aggregators. This determine the context of the field data the aggregators are operating
  * in. It holds both the field names and the index field datas that are associated with them.
+ *
+ * @opensearch.internal
  */
 public class FieldContext {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MissingValues.java b/server/src/main/java/org/opensearch/search/aggregations/support/MissingValues.java
index 3bb14324058d8..da1d9961ed81b 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MissingValues.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MissingValues.java
@@ -37,8 +37,10 @@
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.geometry.Geometry;
 import org.opensearch.index.fielddata.AbstractSortedNumericDocValues;
 import org.opensearch.index.fielddata.AbstractSortedSetDocValues;
+import org.opensearch.index.fielddata.GeoShapeValue;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
@@ -49,6 +51,8 @@
 /**
  * Utility class that allows to return views of {@link ValuesSource}s that
  * replace the missing value with a configured value.
+ *
+ * @opensearch.internal
  */
 public enum MissingValues {
     ;
@@ -111,6 +115,7 @@ public String toString() {
     public static ValuesSource.Numeric replaceMissing(final ValuesSource.Numeric valuesSource, final Number missing) {
         final boolean missingIsFloat = missing.doubleValue() % 1 != 0;
         final boolean isFloatingPoint = valuesSource.isFloatingPoint() || missingIsFloat;
+        final boolean isBigInteger = valuesSource.isBigInteger() && !isFloatingPoint;
         return new ValuesSource.Numeric() {
 
             @Override
@@ -118,6 +123,11 @@ public boolean isFloatingPoint() {
                 return isFloatingPoint;
             }
 
+            @Override
+            public boolean isBigInteger() {
+                return isBigInteger;
+            }
+
             @Override
             public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOException {
                 return replaceMissing(valuesSource.bytesValues(context), new BytesRef(missing.toString()));
@@ -308,6 +318,11 @@ public boolean advanceExact(int doc) throws IOException {
                 return true;
             }
 
+            @Override
+            public int docValueCount() {
+                return values.docValueCount();
+            }
+
             @Override
             public String toString() {
                 return "anon AbstractSortedDocValues of [" + super.toString() + "]";
@@ -338,6 +353,11 @@ public long getValueCount() {
                 return 1 + values.getValueCount();
             }
 
+            @Override
+            public int docValueCount() {
+                return values.docValueCount();
+            }
+
             @Override
             public long nextOrd() throws IOException {
                 if (hasOrds) {
@@ -472,4 +492,26 @@ public String toString() {
             }
         };
     }
+
+    /**
+     * Replace the missing value provided in the param while iterating over a ValuesSource which doesn't have the
+     * value for the field.
+     *
+     * @param missing Value to be returned if doc doesn't contain the data for the field.
+     * @return {@link ValuesSource.GeoShape}
+     */
+    public static ValuesSource.GeoShape replaceMissing(final ValuesSource.GeoShape valuesSource, final Geometry missing) {
+        return new ValuesSource.GeoShape() {
+            @Override
+            public GeoShapeValue getGeoShapeValues(LeafReaderContext context) {
+                final GeoShapeValue currentValueSourceValue = valuesSource.getGeoShapeValues(context);
+                return new GeoShapeValue.MissingGeoShapeValue(currentValueSourceValue, missing);
+            }
+
+            @Override
+            public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOException {
+                return replaceMissing(valuesSource.bytesValues(context), new BytesRef(missing.toString()));
+            }
+        };
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfig.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfig.java
new file mode 100644
index 0000000000000..ab00dae80c4c5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfig.java
@@ -0,0 +1,215 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.support;
+
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.script.Script;
+import org.opensearch.search.aggregations.AggregationBuilder;
+import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
+
+import java.io.IOException;
+import java.time.ZoneId;
+import java.util.Objects;
+
+/**
+ * A configuration that used by multi_terms aggregations.
+ *
+ * @opensearch.internal
+ */
+public class MultiTermsValuesSourceConfig extends BaseMultiValuesSourceFieldConfig {
+    private final ValueType userValueTypeHint;
+    private final String format;
+    private final IncludeExclude includeExclude;
+
+    private static final String NAME = "field_config";
+    public static final ParseField FILTER = new ParseField("filter");
+
+    /**
+     * Parser supplier function
+     *
+     * @opensearch.internal
+     */
+    public interface ParserSupplier {
+        ObjectParser<MultiTermsValuesSourceConfig.Builder, Void> apply(
+            Boolean scriptable,
+            Boolean timezoneAware,
+            Boolean valueTypeHinted,
+            Boolean formatted
+        );
+    }
+
+    public static final MultiTermsValuesSourceConfig.ParserSupplier PARSER = (scriptable, timezoneAware, valueTypeHinted, formatted) -> {
+
+        ObjectParser<MultiTermsValuesSourceConfig.Builder, Void> parser = new ObjectParser<>(
+            MultiTermsValuesSourceConfig.NAME,
+            MultiTermsValuesSourceConfig.Builder::new
+        );
+
+        BaseMultiValuesSourceFieldConfig.PARSER.apply(parser, scriptable, timezoneAware);
+
+        if (valueTypeHinted) {
+            parser.declareField(
+                MultiTermsValuesSourceConfig.Builder::setUserValueTypeHint,
+                p -> ValueType.lenientParse(p.text()),
+                ValueType.VALUE_TYPE,
+                ObjectParser.ValueType.STRING
+            );
+        }
+
+        if (formatted) {
+            parser.declareField(
+                MultiTermsValuesSourceConfig.Builder::setFormat,
+                XContentParser::text,
+                ParseField.CommonFields.FORMAT,
+                ObjectParser.ValueType.STRING
+            );
+        }
+
+        parser.declareField(
+            (b, v) -> b.setIncludeExclude(IncludeExclude.merge(b.getIncludeExclude(), v)),
+            IncludeExclude::parseExclude,
+            IncludeExclude.EXCLUDE_FIELD,
+            ObjectParser.ValueType.STRING_ARRAY
+        );
+
+        return parser;
+    };
+
+    protected MultiTermsValuesSourceConfig(
+        String fieldName,
+        Object missing,
+        Script script,
+        ZoneId timeZone,
+        ValueType userValueTypeHint,
+        String format,
+        IncludeExclude includeExclude
+    ) {
+        super(fieldName, missing, script, timeZone);
+        this.userValueTypeHint = userValueTypeHint;
+        this.format = format;
+        this.includeExclude = includeExclude;
+    }
+
+    public MultiTermsValuesSourceConfig(StreamInput in) throws IOException {
+        super(in);
+        this.userValueTypeHint = in.readOptionalWriteable(ValueType::readFromStream);
+        this.format = in.readOptionalString();
+        this.includeExclude = in.readOptionalWriteable(IncludeExclude::new);
+    }
+
+    public ValueType getUserValueTypeHint() {
+        return userValueTypeHint;
+    }
+
+    public String getFormat() {
+        return format;
+    }
+
+    /**
+     * Get terms to include and exclude from the aggregation results
+     */
+    public IncludeExclude getIncludeExclude() {
+        return includeExclude;
+    }
+
+    @Override
+    public void doWriteTo(StreamOutput out) throws IOException {
+        out.writeOptionalWriteable(userValueTypeHint);
+        out.writeOptionalString(format);
+        out.writeOptionalWriteable(includeExclude);
+    }
+
+    @Override
+    public void doXContentBody(XContentBuilder builder, Params params) throws IOException {
+        if (userValueTypeHint != null) {
+            builder.field(AggregationBuilder.CommonFields.VALUE_TYPE.getPreferredName(), userValueTypeHint.getPreferredName());
+        }
+        if (format != null) {
+            builder.field(AggregationBuilder.CommonFields.FORMAT.getPreferredName(), format);
+        }
+        if (includeExclude != null) {
+            includeExclude.toXContent(builder, params);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        if (super.equals(o) == false) return false;
+
+        MultiTermsValuesSourceConfig that = (MultiTermsValuesSourceConfig) o;
+        return Objects.equals(userValueTypeHint, that.userValueTypeHint)
+            && Objects.equals(format, that.format)
+            && Objects.equals(includeExclude, that.includeExclude);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), userValueTypeHint, format, includeExclude);
+    }
+
+    /**
+     * Builder for the multi terms values source configuration
+     *
+     * @opensearch.internal
+     */
+    public static class Builder extends BaseMultiValuesSourceFieldConfig.Builder<MultiTermsValuesSourceConfig, Builder> {
+        private ValueType userValueTypeHint = null;
+        private String format;
+        private IncludeExclude includeExclude = null;
+
+        public IncludeExclude getIncludeExclude() {
+            return includeExclude;
+        }
+
+        public Builder setIncludeExclude(IncludeExclude includeExclude) {
+            this.includeExclude = includeExclude;
+            return this;
+        }
+
+        public ValueType getUserValueTypeHint() {
+            return userValueTypeHint;
+        }
+
+        public Builder setUserValueTypeHint(ValueType userValueTypeHint) {
+            this.userValueTypeHint = userValueTypeHint;
+            return this;
+        }
+
+        public String getFormat() {
+            return format;
+        }
+
+        public Builder setFormat(String format) {
+            this.format = format;
+            return this;
+        }
+
+        public MultiTermsValuesSourceConfig build() {
+            if (Strings.isNullOrEmpty(fieldName) && script == null) {
+                throw new IllegalArgumentException(
+                    "["
+                        + ParseField.CommonFields.FIELD.getPreferredName()
+                        + "] and ["
+                        + Script.SCRIPT_PARSE_FIELD.getPreferredName()
+                        + "] cannot both be null.  "
+                        + "Please specify one or the other."
+                );
+            }
+            return new MultiTermsValuesSourceConfig(fieldName, missing, script, timeZone, userValueTypeHint, format, includeExclude);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSource.java
index ecc03b046e473..0889a1c90d12d 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSource.java
@@ -43,10 +43,17 @@
 
 /**
  * Class to encapsulate a set of ValuesSource objects labeled by field name
+ *
+ * @opensearch.internal
  */
 public abstract class MultiValuesSource<VS extends ValuesSource> {
     protected Map<String, VS> values;
 
+    /**
+     * Numeric format
+     *
+     * @opensearch.internal
+     */
     public static class NumericMultiValuesSource extends MultiValuesSource<ValuesSource.Numeric> {
         public NumericMultiValuesSource(Map<String, ValuesSourceConfig> valuesSourceConfigs, QueryShardContext context) {
             values = new HashMap<>(valuesSourceConfigs.size());
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregationBuilder.java
index 72d508de1d12e..e3f914ca259f6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregationBuilder.java
@@ -32,9 +32,9 @@
 package org.opensearch.search.aggregations.support;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
@@ -53,10 +53,17 @@
  * can pull values from multiple fields).
  *
  * A limitation of this class is that all the ValuesSource's being refereenced must be of the same type.
+ *
+ * @opensearch.internal
  */
 public abstract class MultiValuesSourceAggregationBuilder<AB extends MultiValuesSourceAggregationBuilder<AB>> extends
     AbstractAggregationBuilder<AB> {
 
+    /**
+     * Base leaf only class
+     *
+     * @opensearch.internal
+     */
     public abstract static class LeafOnly<AB extends MultiValuesSourceAggregationBuilder<AB>> extends MultiValuesSourceAggregationBuilder<
         AB> {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregatorFactory.java
index 0ce8e3ea9b5a9..499fa41096de8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceAggregatorFactory.java
@@ -43,6 +43,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base class for MultiValuesSource aggregator factories
+ *
+ * @opensearch.internal
+ */
 public abstract class MultiValuesSourceAggregatorFactory extends AggregatorFactory {
 
     protected final Map<String, ValuesSourceConfig> configs;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfig.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfig.java
index 54450763148c8..e11e13f803ac4 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfig.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfig.java
@@ -33,31 +33,27 @@
 package org.opensearch.search.aggregations.support;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.time.DateUtils;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.script.Script;
 
 import java.io.IOException;
 import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.util.Objects;
 
-public class MultiValuesSourceFieldConfig implements Writeable, ToXContentObject {
-    private final String fieldName;
-    private final Object missing;
-    private final Script script;
-    private final ZoneId timeZone;
+/**
+ * Base field configuration class for multi values
+ *
+ * @opensearch.internal
+ */
+public class MultiValuesSourceFieldConfig extends BaseMultiValuesSourceFieldConfig {
     private final QueryBuilder filter;
 
     private static final String NAME = "field_config";
@@ -73,32 +69,7 @@ public class MultiValuesSourceFieldConfig implements Writeable, ToXContentObject
             MultiValuesSourceFieldConfig.Builder::new
         );
 
-        parser.declareString(MultiValuesSourceFieldConfig.Builder::setFieldName, ParseField.CommonFields.FIELD);
-        parser.declareField(
-            MultiValuesSourceFieldConfig.Builder::setMissing,
-            XContentParser::objectText,
-            ParseField.CommonFields.MISSING,
-            ObjectParser.ValueType.VALUE
-        );
-
-        if (scriptable) {
-            parser.declareField(
-                MultiValuesSourceFieldConfig.Builder::setScript,
-                (p, context) -> Script.parse(p),
-                Script.SCRIPT_PARSE_FIELD,
-                ObjectParser.ValueType.OBJECT_OR_STRING
-            );
-        }
-
-        if (timezoneAware) {
-            parser.declareField(MultiValuesSourceFieldConfig.Builder::setTimeZone, p -> {
-                if (p.currentToken() == XContentParser.Token.VALUE_STRING) {
-                    return ZoneId.of(p.text());
-                } else {
-                    return ZoneOffset.ofHours(p.intValue());
-                }
-            }, ParseField.CommonFields.TIME_ZONE, ObjectParser.ValueType.LONG);
-        }
+        BaseMultiValuesSourceFieldConfig.PARSER.apply(parser, scriptable, timezoneAware);
 
         if (filtered) {
             parser.declareField(
@@ -112,26 +83,12 @@ public class MultiValuesSourceFieldConfig implements Writeable, ToXContentObject
     };
 
     protected MultiValuesSourceFieldConfig(String fieldName, Object missing, Script script, ZoneId timeZone, QueryBuilder filter) {
-        this.fieldName = fieldName;
-        this.missing = missing;
-        this.script = script;
-        this.timeZone = timeZone;
+        super(fieldName, missing, script, timeZone);
         this.filter = filter;
     }
 
     public MultiValuesSourceFieldConfig(StreamInput in) throws IOException {
-        if (in.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
-            this.fieldName = in.readOptionalString();
-        } else {
-            this.fieldName = in.readString();
-        }
-        this.missing = in.readGenericValue();
-        this.script = in.readOptionalWriteable(Script::new);
-        if (in.getVersion().before(LegacyESVersion.V_7_0_0)) {
-            this.timeZone = DateUtils.dateTimeZoneToZoneId(in.readOptionalTimeZone());
-        } else {
-            this.timeZone = in.readOptionalZoneId();
-        }
+        super(in);
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_8_0)) {
             this.filter = in.readOptionalNamedWriteable(QueryBuilder.class);
         } else {
@@ -139,133 +96,48 @@ public MultiValuesSourceFieldConfig(StreamInput in) throws IOException {
         }
     }
 
-    public Object getMissing() {
-        return missing;
-    }
-
-    public Script getScript() {
-        return script;
-    }
-
-    public ZoneId getTimeZone() {
-        return timeZone;
-    }
-
-    public String getFieldName() {
-        return fieldName;
-    }
-
     public QueryBuilder getFilter() {
         return filter;
     }
 
     @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        if (out.getVersion().onOrAfter(LegacyESVersion.V_7_6_0)) {
-            out.writeOptionalString(fieldName);
-        } else {
-            out.writeString(fieldName);
-        }
-        out.writeGenericValue(missing);
-        out.writeOptionalWriteable(script);
-        if (out.getVersion().before(LegacyESVersion.V_7_0_0)) {
-            out.writeOptionalTimeZone(DateUtils.zoneIdToDateTimeZone(timeZone));
-        } else {
-            out.writeOptionalZoneId(timeZone);
-        }
+    public void doWriteTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_8_0)) {
             out.writeOptionalNamedWriteable(filter);
         }
     }
 
     @Override
-    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        builder.startObject();
-        if (missing != null) {
-            builder.field(ParseField.CommonFields.MISSING.getPreferredName(), missing);
-        }
-        if (script != null) {
-            builder.field(Script.SCRIPT_PARSE_FIELD.getPreferredName(), script);
-        }
-        if (fieldName != null) {
-            builder.field(ParseField.CommonFields.FIELD.getPreferredName(), fieldName);
-        }
-        if (timeZone != null) {
-            builder.field(ParseField.CommonFields.TIME_ZONE.getPreferredName(), timeZone.getId());
-        }
+    public void doXContentBody(XContentBuilder builder, Params params) throws IOException {
         if (filter != null) {
             builder.field(FILTER.getPreferredName());
             filter.toXContent(builder, params);
         }
-        builder.endObject();
-        return builder;
     }
 
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
+        if (super.equals(o) == false) return false;
+
         MultiValuesSourceFieldConfig that = (MultiValuesSourceFieldConfig) o;
-        return Objects.equals(fieldName, that.fieldName)
-            && Objects.equals(missing, that.missing)
-            && Objects.equals(script, that.script)
-            && Objects.equals(timeZone, that.timeZone)
-            && Objects.equals(filter, that.filter);
+        return Objects.equals(filter, that.filter);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(fieldName, missing, script, timeZone, filter);
+        return Objects.hash(super.hashCode(), filter);
     }
 
-    @Override
-    public String toString() {
-        return Strings.toString(this);
-    }
-
-    public static class Builder {
-        private String fieldName;
-        private Object missing = null;
-        private Script script = null;
-        private ZoneId timeZone = null;
+    /**
+     * Builder for the field config
+     *
+     * @opensearch.internal
+     */
+    public static class Builder extends BaseMultiValuesSourceFieldConfig.Builder<BaseMultiValuesSourceFieldConfig, Builder> {
         private QueryBuilder filter = null;
 
-        public String getFieldName() {
-            return fieldName;
-        }
-
-        public Builder setFieldName(String fieldName) {
-            this.fieldName = fieldName;
-            return this;
-        }
-
-        public Object getMissing() {
-            return missing;
-        }
-
-        public Builder setMissing(Object missing) {
-            this.missing = missing;
-            return this;
-        }
-
-        public Script getScript() {
-            return script;
-        }
-
-        public Builder setScript(Script script) {
-            this.script = script;
-            return this;
-        }
-
-        public ZoneId getTimeZone() {
-            return timeZone;
-        }
-
-        public Builder setTimeZone(ZoneId timeZone) {
-            this.timeZone = timeZone;
-            return this;
-        }
-
         public Builder setFilter(QueryBuilder filter) {
             this.filter = filter;
             return this;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceParseHelper.java b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceParseHelper.java
index 82054ab53af41..ce09a4738e7d0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceParseHelper.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/MultiValuesSourceParseHelper.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.AbstractObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
+/**
+ * Helper class to parse multi values sources
+ *
+ * @opensearch.internal
+ */
 public final class MultiValuesSourceParseHelper {
 
     public static <T> void declareCommon(
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValueType.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValueType.java
index 5912a01664e47..59fa2e03f0bc3 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValueType.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValueType.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.search.DocValueFormat;
 
@@ -44,6 +44,11 @@
 import java.util.Arrays;
 import java.util.List;
 
+/**
+ * Enum to signal what kind of value type is used in the aggregator
+ *
+ * @opensearch.internal
+ */
 public enum ValueType implements Writeable {
 
     STRING((byte) 1, "string", "string", CoreValuesSourceType.BYTES, DocValueFormat.RAW),
@@ -63,7 +68,8 @@ public enum ValueType implements Writeable {
     NUMERIC((byte) 7, "numeric", "numeric", CoreValuesSourceType.NUMERIC, DocValueFormat.RAW),
     GEOPOINT((byte) 8, "geo_point", "geo_point", CoreValuesSourceType.GEOPOINT, DocValueFormat.GEOHASH),
     BOOLEAN((byte) 9, "boolean", "boolean", CoreValuesSourceType.BOOLEAN, DocValueFormat.BOOLEAN),
-    RANGE((byte) 10, "range", "range", CoreValuesSourceType.RANGE, DocValueFormat.RAW);
+    RANGE((byte) 10, "range", "range", CoreValuesSourceType.RANGE, DocValueFormat.RAW),
+    UNSIGNED_LONG((byte) 11, "unsigned_long", "unsigned_long", CoreValuesSourceType.NUMERIC, DocValueFormat.UNSIGNED_LONG),;
 
     final String description;
     final ValuesSourceType valuesSourceType;
@@ -93,6 +99,7 @@ public ValuesSourceType getValuesSourceType() {
         ValueType.DOUBLE,
         ValueType.DATE,
         ValueType.LONG,
+        ValueType.UNSIGNED_LONG,
         ValueType.NUMBER,
         ValueType.NUMERIC,
         ValueType.BOOLEAN
@@ -139,6 +146,8 @@ public static ValueType lenientParse(String type) {
             case "short":
             case "byte":
                 return LONG;
+            case "unsigned_long":
+                return UNSIGNED_LONG;
             case "date":
                 return DATE;
             case "ip":
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSource.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSource.java
index a0875737f370e..67d311db964d6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSource.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSource.java
@@ -44,12 +44,14 @@
 import org.opensearch.common.Rounding;
 import org.opensearch.common.Rounding.Prepared;
 import org.opensearch.common.lucene.ScorerAware;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.index.fielddata.AbstractSortingNumericDocValues;
 import org.opensearch.index.fielddata.DocValueBits;
+import org.opensearch.index.fielddata.GeoShapeValue;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexGeoPointFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
+import org.opensearch.index.fielddata.IndexNumericFieldData.NumericType;
 import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
 import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.MultiGeoPointValues;
@@ -57,6 +59,7 @@
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.fielddata.SortingBinaryDocValues;
 import org.opensearch.index.fielddata.SortingNumericDoubleValues;
+import org.opensearch.index.fielddata.plain.AbstractGeoShapeIndexFieldData;
 import org.opensearch.index.mapper.RangeType;
 import org.opensearch.script.AggregationScript;
 import org.opensearch.search.aggregations.AggregationExecutionException;
@@ -69,6 +72,11 @@
 import java.util.function.Function;
 import java.util.function.LongUnaryOperator;
 
+/**
+ * Base class for a ValuesSource; the primitive data for an agg
+ *
+ * @opensearch.internal
+ */
 public abstract class ValuesSource {
 
     /**
@@ -98,6 +106,11 @@ public boolean hasGlobalOrdinals() {
         return false;
     }
 
+    /**
+     * Range type
+     *
+     * @opensearch.internal
+     */
     public static class Range extends ValuesSource {
         private final RangeType rangeType;
         protected final IndexFieldData<?> indexFieldData;
@@ -129,6 +142,11 @@ public RangeType rangeType() {
         }
     }
 
+    /**
+     * Bytes type
+     *
+     * @opensearch.internal
+     */
     public abstract static class Bytes extends ValuesSource {
 
         @Override
@@ -142,6 +160,11 @@ public final Function<Rounding, Rounding.Prepared> roundingPreparer(IndexReader
             throw new AggregationExecutionException("can't round a [BYTES]");
         }
 
+        /**
+         * Provides ordinals for bytes
+         *
+         * @opensearch.internal
+         */
         public abstract static class WithOrdinals extends Bytes {
 
             public static final WithOrdinals EMPTY = new WithOrdinals() {
@@ -206,6 +229,11 @@ public long globalMaxOrd(IndexSearcher indexSearcher) throws IOException {
                 }
             }
 
+            /**
+             * Field data for the bytes values source
+             *
+             * @opensearch.internal
+             */
             public static class FieldData extends WithOrdinals {
 
                 protected final IndexOrdinalsFieldData indexFieldData;
@@ -252,6 +280,11 @@ public LongUnaryOperator globalOrdinalsMapping(LeafReaderContext context) throws
             }
         }
 
+        /**
+         * Field data without ordinals
+         *
+         * @opensearch.internal
+         */
         public static class FieldData extends Bytes {
 
             protected final IndexFieldData<?> indexFieldData;
@@ -269,6 +302,8 @@ public SortedBinaryDocValues bytesValues(LeafReaderContext context) {
 
         /**
          * {@link ValuesSource} implementation for stand alone scripts returning a Bytes value
+         *
+         * @opensearch.internal
          */
         public static class Script extends Bytes {
 
@@ -292,6 +327,8 @@ public boolean needsScores() {
         // No need to implement ReaderContextAware here, the delegate already takes care of updating data structures
         /**
          * {@link ValuesSource} subclass for Bytes fields with a Value Script applied
+         *
+         * @opensearch.internal
          */
         public static class WithScript extends Bytes {
 
@@ -313,6 +350,11 @@ public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOExc
                 return new BytesValues(delegate.bytesValues(context), script.newInstance(context));
             }
 
+            /**
+             * Bytes values
+             *
+             * @opensearch.internal
+             */
             static class BytesValues extends SortingBinaryDocValues implements ScorerAware {
 
                 private final SortedBinaryDocValues bytesValues;
@@ -353,6 +395,11 @@ public boolean advanceExact(int doc) throws IOException {
         }
     }
 
+    /**
+     * Numeric values source type
+     *
+     * @opensearch.internal
+     */
     public abstract static class Numeric extends ValuesSource {
 
         public static final Numeric EMPTY = new Numeric() {
@@ -362,6 +409,11 @@ public boolean isFloatingPoint() {
                 return false;
             }
 
+            @Override
+            public boolean isBigInteger() {
+                return false;
+            }
+
             @Override
             public SortedNumericDocValues longValues(LeafReaderContext context) {
                 return DocValues.emptySortedNumeric();
@@ -382,6 +434,9 @@ public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOExc
         /** Whether the underlying data is floating-point or not. */
         public abstract boolean isFloatingPoint();
 
+        /** Whether the underlying data is big integer or not. */
+        public abstract boolean isBigInteger();
+
         /** Get the current {@link SortedNumericDocValues}. */
         public abstract SortedNumericDocValues longValues(LeafReaderContext context) throws IOException;
 
@@ -390,7 +445,7 @@ public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOExc
 
         @Override
         public DocValueBits docsWithValue(LeafReaderContext context) throws IOException {
-            if (isFloatingPoint()) {
+            if (isFloatingPoint() || isBigInteger()) {
                 final SortedNumericDoubleValues values = doubleValues(context);
                 return org.opensearch.index.fielddata.FieldData.docsWithValue(values);
             } else {
@@ -406,6 +461,8 @@ public Function<Rounding, Prepared> roundingPreparer(IndexReader reader) throws
 
         /**
          * {@link ValuesSource} subclass for Numeric fields with a Value Script applied
+         *
+         * @opensearch.internal
          */
         public static class WithScript extends Numeric {
 
@@ -422,6 +479,11 @@ public boolean isFloatingPoint() {
                 return true; // even if the underlying source produces longs, scripts can change them to doubles
             }
 
+            @Override
+            public boolean isBigInteger() {
+                return false; /* always fall back to floating point */
+            }
+
             @Override
             public boolean needsScores() {
                 return script.needs_score();
@@ -442,6 +504,11 @@ public SortedNumericDoubleValues doubleValues(LeafReaderContext context) throws
                 return new DoubleValues(delegate.doubleValues(context), script.newInstance(context));
             }
 
+            /**
+             * Long values source type
+             *
+             * @opensearch.internal
+             */
             static class LongValues extends AbstractSortingNumericDocValues implements ScorerAware {
 
                 private final SortedNumericDocValues longValues;
@@ -473,6 +540,11 @@ public boolean advanceExact(int target) throws IOException {
                 }
             }
 
+            /**
+             * Double values source type
+             *
+             * @opensearch.internal
+             */
             static class DoubleValues extends SortingNumericDoubleValues implements ScorerAware {
 
                 private final SortedNumericDoubleValues doubleValues;
@@ -505,6 +577,11 @@ public boolean advanceExact(int target) throws IOException {
             }
         }
 
+        /**
+         * Field data for numerics
+         *
+         * @opensearch.internal
+         */
         public static class FieldData extends Numeric {
 
             protected final IndexNumericFieldData indexFieldData;
@@ -518,6 +595,11 @@ public boolean isFloatingPoint() {
                 return indexFieldData.getNumericType().isFloatingPoint();
             }
 
+            @Override
+            public boolean isBigInteger() {
+                return indexFieldData.getNumericType() == NumericType.UNSIGNED_LONG;
+            }
+
             @Override
             public SortedBinaryDocValues bytesValues(LeafReaderContext context) {
                 return indexFieldData.load(context).getBytesValues();
@@ -536,6 +618,8 @@ public SortedNumericDoubleValues doubleValues(LeafReaderContext context) {
 
         /**
          * {@link ValuesSource} implementation for stand alone scripts returning a Numeric value
+         *
+         * @opensearch.internal
          */
         public static class Script extends Numeric {
             private final AggregationScript.LeafFactory script;
@@ -551,6 +635,11 @@ public boolean isFloatingPoint() {
                 return scriptValueType != null ? scriptValueType == ValueType.DOUBLE : true;
             }
 
+            @Override
+            public boolean isBigInteger() {
+                return scriptValueType != null ? scriptValueType == ValueType.UNSIGNED_LONG : false;
+            }
+
             @Override
             public SortedNumericDocValues longValues(LeafReaderContext context) throws IOException {
                 return new ScriptLongValues(script.newInstance(context));
@@ -574,6 +663,11 @@ public boolean needsScores() {
 
     }
 
+    /**
+     * Geo point values source
+     *
+     * @opensearch.internal
+     */
     public abstract static class GeoPoint extends ValuesSource {
 
         public static final GeoPoint EMPTY = new GeoPoint() {
@@ -603,6 +697,11 @@ public final Function<Rounding, Rounding.Prepared> roundingPreparer(IndexReader
 
         public abstract MultiGeoPointValues geoPointValues(LeafReaderContext context);
 
+        /**
+         * Field data for geo point values source
+         *
+         * @opensearch.internal
+         */
         public static class Fielddata extends GeoPoint {
 
             protected final IndexGeoPointFieldData indexFieldData;
@@ -621,4 +720,89 @@ public org.opensearch.index.fielddata.MultiGeoPointValues geoPointValues(LeafRea
             }
         }
     }
+
+    /**
+     * The primitive data type for doing an aggregation on the GeoShape
+     */
+    public abstract static class GeoShape extends ValuesSource {
+        public static final GeoShape EMPTY = new GeoShape() {
+            /**
+             * This provides the {@link GeoShapeValue} after reading from LeafReaderContext
+             *
+             * @param context {@link LeafReaderContext}
+             * @return {@link GeoShapeValue}
+             */
+            @Override
+            public GeoShapeValue getGeoShapeValues(LeafReaderContext context) {
+                return org.opensearch.index.fielddata.FieldData.emptyGeoShape();
+            }
+
+            /**
+             * Get the current {@link BytesValues}.
+             */
+            @Override
+            public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOException {
+                return org.opensearch.index.fielddata.FieldData.emptySortedBinary();
+            }
+        };
+
+        /**
+         * This is getting used in the {@link org.opensearch.search.aggregations.bucket.missing.MissingAggregator}
+         * @param context {@link LeafReaderContext}
+         * @return DocValueBits
+         */
+        @Override
+        public DocValueBits docsWithValue(LeafReaderContext context) {
+            final GeoShapeValue geoShapeValue = getGeoShapeValues(context);
+            return org.opensearch.index.fielddata.FieldData.docsWithValue(geoShapeValue);
+        }
+
+        @Override
+        public Function<Rounding, Prepared> roundingPreparer(IndexReader reader) {
+            throw new AggregationExecutionException("can't round a [GEO_SHAPE]");
+        }
+
+        /**
+         * This provides the {@link GeoShapeValue} after reading from LeafReaderContext
+         * @param context {@link LeafReaderContext}
+         * @return {@link GeoShapeValue}
+         */
+        public abstract GeoShapeValue getGeoShapeValues(LeafReaderContext context);
+
+        /**
+         * Field data for geo shape values source
+         *
+         * @opensearch.internal
+         */
+        public static class FieldData extends GeoShape {
+
+            protected final AbstractGeoShapeIndexFieldData indexFieldData;
+
+            public FieldData(AbstractGeoShapeIndexFieldData indexFieldData) {
+                this.indexFieldData = indexFieldData;
+            }
+
+            /**
+             * Get the current {@link BytesValues}.
+             *
+             * @param context {@link LeafReaderContext}
+             * @return SortedBinaryDocValues
+             */
+            @Override
+            public SortedBinaryDocValues bytesValues(LeafReaderContext context) throws IOException {
+                return indexFieldData.load(context).getBytesValues();
+            }
+
+            /**
+             * This provides the {@link GeoShapeValue} after reading from LeafReaderContext
+             *
+             * @param context {@link LeafReaderContext}
+             * @return {@link GeoShapeValue}
+             */
+            @Override
+            public GeoShapeValue getGeoShapeValues(LeafReaderContext context) {
+                return indexFieldData.load(context).getGeoShapeValue();
+            }
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregationBuilder.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregationBuilder.java
index 70c36be06a9ae..68448d93052b8 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregationBuilder.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregationBuilder.java
@@ -33,14 +33,15 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.joda.Joda;
 import org.opensearch.common.time.DateUtils;
-import org.opensearch.common.xcontent.AbstractObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.AbstractObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.AbstractAggregationBuilder;
@@ -54,6 +55,11 @@
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Base class for all values source agg builders
+ *
+ * @opensearch.internal
+ */
 public abstract class ValuesSourceAggregationBuilder<AB extends ValuesSourceAggregationBuilder<AB>> extends AbstractAggregationBuilder<AB> {
 
     public static <T> void declareFields(
@@ -135,6 +141,11 @@ public static <T> void declareFields(
         }
     }
 
+    /**
+     * Base leaf only
+     *
+     * @opensearch.internal
+     */
     public abstract static class LeafOnly<VS extends ValuesSource, AB extends ValuesSourceAggregationBuilder<AB>> extends
         ValuesSourceAggregationBuilder<AB> {
 
@@ -224,7 +235,7 @@ private void read(StreamInput in) throws IOException {
         format = in.readOptionalString();
         missing = in.readGenericValue();
         if (in.getVersion().before(LegacyESVersion.V_7_0_0)) {
-            timeZone = DateUtils.dateTimeZoneToZoneId(in.readOptionalTimeZone());
+            timeZone = DateUtils.dateTimeZoneToZoneId(Joda.readOptionalTimeZone(in));
         } else {
             timeZone = in.readOptionalZoneId();
         }
@@ -250,7 +261,7 @@ protected final void doWriteTo(StreamOutput out) throws IOException {
         out.writeOptionalString(format);
         out.writeGenericValue(missing);
         if (out.getVersion().before(LegacyESVersion.V_7_0_0)) {
-            out.writeOptionalTimeZone(DateUtils.zoneIdToDateTimeZone(timeZone));
+            Joda.writeOptionalTimeZone(out, DateUtils.zoneIdToDateTimeZone(timeZone));
         } else {
             out.writeOptionalZoneId(timeZone);
         }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
index 14d0aa72535fa..69a4a5d8b6703 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
@@ -42,6 +42,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Base class for all values source agg factories
+ *
+ * @opensearch.internal
+ */
 public abstract class ValuesSourceAggregatorFactory extends AggregatorFactory {
 
     protected ValuesSourceConfig config;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceConfig.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceConfig.java
index 623b88c595ce8..b5bd355bb5847 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceConfig.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceConfig.java
@@ -49,6 +49,8 @@
 /**
  * A configuration that tells aggregations how to retrieve data from the index
  * in order to run a specific aggregation.
+ *
+ * @opensearch.internal
  */
 public class ValuesSourceConfig {
 
@@ -321,7 +323,7 @@ public ValuesSourceConfig(
         if (!valid()) {
             // TODO: resolve no longer generates invalid configs. Once VSConfig is immutable, we can drop this check
             throw new IllegalStateException(
-                "value source config is invalid; must have either a field context or a script or marked as unwrapped"
+                "value source config is invalid; must have either a field context or a script or marked as unmapped"
             );
         }
         valuesSource = ConstructValuesSource(missing, format, nowSupplier);
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceRegistry.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceRegistry.java
index c1518491b09f9..0cb5a12bac4af 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceRegistry.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceRegistry.java
@@ -49,9 +49,15 @@
  * directly instantiate this class, instead get an already-configured copy from {@link QueryShardContext#getValuesSourceRegistry()}, or (in
  * the case of some test scenarios only) directly from {@link SearchModule#getValuesSourceRegistry()}
  *
+ * @opensearch.internal
  */
 public class ValuesSourceRegistry {
 
+    /**
+     * The registry key for the values source registry key
+     *
+     * @opensearch.internal
+     */
     public static final class RegistryKey<T> {
         private final String name;
         private final Class<T> supplierType;
@@ -81,6 +87,11 @@ public int hashCode() {
 
     public static final RegistryKey UNREGISTERED_KEY = new RegistryKey("unregistered", RegistryKey.class);
 
+    /**
+     * Builder for the values source registry
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private final AggregationUsageService.Builder usageServiceBuilder;
         private Map<RegistryKey<?>, List<Map.Entry<ValuesSourceType, ?>>> aggregatorRegistry = new HashMap<>();
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceType.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceType.java
index 6f7a9ec0cc955..86102e63297d1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceType.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceType.java
@@ -57,6 +57,8 @@
  * if logically the type needs a more restricted use (e.g. even though dates are stored as numbers, it doesn't make sense to pass them to
  * a sum aggregation).  When adding a new ValuesSourceType, new aggregators should be added and registered at the same time, to add support
  * for the new type to existing aggregations, as appropriate.
+ *
+ * @opensearch.internal
  */
 public interface ValuesSourceType {
     /**
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/support/package-info.java
index b31c2e1d7b5c4..dd2c16f1daa0e 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/package-info.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/package-info.java
@@ -30,8 +30,6 @@
  * GitHub history for details.
  */
 
-package org.opensearch.search.aggregations.support;
-
 /**
  * <p>
  * This package holds shared code for the aggregations framework, especially around dealing with values.
@@ -45,7 +43,7 @@
  * output). A class hierarchy defines the type of values returned by the source.  The top level sub-classes define type-specific behavior,
  * such as {@link org.opensearch.search.aggregations.support.ValuesSource.Numeric#isFloatingPoint()}.  Second level subclasses are
  * then specialized based on where they read values from, e.g. script or field cases.  There are also adapter classes like
- * {@link org.opensearch.search.aggregations.bucket.geogrid.CellIdSource} which do run-time conversion from one type to another, often
+ * org.opensearch.search.aggregations.bucket.geogrid.CellIdSource which do run-time conversion from one type to another, often
  * dependent on a user specified parameter (precision in that case).
  * </p>
  *
@@ -88,3 +86,4 @@
  * </p>
  *
  */
+package org.opensearch.search.aggregations.support;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptBytesValues.java b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptBytesValues.java
index 327437aa2baa2..349bd8e14edf6 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptBytesValues.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptBytesValues.java
@@ -33,7 +33,7 @@
 
 import org.apache.lucene.search.Scorable;
 import org.opensearch.common.lucene.ScorerAware;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
 import org.opensearch.index.fielddata.SortingBinaryDocValues;
 import org.opensearch.script.AggregationScript;
@@ -44,6 +44,8 @@
 
 /**
  * {@link SortedBinaryDocValues} implementation that reads values from a script.
+ *
+ * @opensearch.internal
  */
 public class ScriptBytesValues extends SortingBinaryDocValues implements ScorerAware {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptDoubleValues.java b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptDoubleValues.java
index ab9a36037c601..921a3bb344ae0 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptDoubleValues.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptDoubleValues.java
@@ -32,12 +32,12 @@
 package org.opensearch.search.aggregations.support.values;
 
 import org.apache.lucene.search.Scorable;
-import org.joda.time.ReadableInstant;
 import org.opensearch.common.lucene.ScorerAware;
 import org.opensearch.index.fielddata.SortingNumericDoubleValues;
 import org.opensearch.script.AggregationScript;
 import org.opensearch.script.JodaCompatibleZonedDateTime;
 import org.opensearch.search.aggregations.AggregationExecutionException;
+import org.joda.time.ReadableInstant;
 
 import java.io.IOException;
 import java.lang.reflect.Array;
@@ -46,6 +46,8 @@
 
 /**
  * {@link SortingNumericDoubleValues} implementation which is based on a script
+ *
+ * @opensearch.internal
  */
 public class ScriptDoubleValues extends SortingNumericDoubleValues implements ScorerAware {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptLongValues.java b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptLongValues.java
index 67a55383d101d..5f169898f4653 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptLongValues.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/values/ScriptLongValues.java
@@ -33,12 +33,12 @@
 
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.util.LongValues;
-import org.joda.time.ReadableInstant;
 import org.opensearch.common.lucene.ScorerAware;
 import org.opensearch.index.fielddata.AbstractSortingNumericDocValues;
 import org.opensearch.script.AggregationScript;
 import org.opensearch.script.JodaCompatibleZonedDateTime;
 import org.opensearch.search.aggregations.AggregationExecutionException;
+import org.joda.time.ReadableInstant;
 
 import java.io.IOException;
 import java.lang.reflect.Array;
@@ -48,6 +48,8 @@
 
 /**
  * {@link LongValues} implementation which is based on a script
+ *
+ * @opensearch.internal
  */
 public class ScriptLongValues extends AbstractSortingNumericDocValues implements ScorerAware {
 
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/values/package-info.java b/server/src/main/java/org/opensearch/search/aggregations/support/values/package-info.java
new file mode 100644
index 0000000000000..d39782586fc1a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/values/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Values Source for Aggregations package. */
+package org.opensearch.search.aggregations.support.values;
diff --git a/server/src/main/java/org/opensearch/search/backpressure/CancellationSettingsListener.java b/server/src/main/java/org/opensearch/search/backpressure/CancellationSettingsListener.java
new file mode 100644
index 0000000000000..f630b3b8ed987
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/CancellationSettingsListener.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+/**
+ * Listener for callbacks related to cancellation settings
+ */
+public interface CancellationSettingsListener {
+
+    void onRatioChanged(double ratio);
+
+    void onRateChanged(double rate);
+
+    void onBurstChanged(double burst);
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java
new file mode 100644
index 0000000000000..4f6c2c327509d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureService.java
@@ -0,0 +1,417 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.monitor.jvm.JvmStats;
+import org.opensearch.monitor.process.ProcessProbe;
+import org.opensearch.search.backpressure.settings.SearchBackpressureMode;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.search.backpressure.stats.SearchBackpressureStats;
+import org.opensearch.search.backpressure.stats.SearchShardTaskStats;
+import org.opensearch.search.backpressure.stats.SearchTaskStats;
+import org.opensearch.search.backpressure.trackers.CpuUsageTracker;
+import org.opensearch.search.backpressure.trackers.ElapsedTimeTracker;
+import org.opensearch.search.backpressure.trackers.HeapUsageTracker;
+import org.opensearch.search.backpressure.trackers.NodeDuressTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.SearchBackpressureTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+import org.opensearch.tasks.TaskManager;
+import org.opensearch.tasks.TaskResourceTrackingService;
+import org.opensearch.tasks.TaskResourceTrackingService.TaskCompletionListener;
+import org.opensearch.threadpool.Scheduler;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.DoubleSupplier;
+import java.util.function.LongSupplier;
+import java.util.stream.Collectors;
+
+import static org.opensearch.search.backpressure.trackers.HeapUsageTracker.isHeapTrackingSupported;
+
+/**
+ * SearchBackpressureService is responsible for monitoring and cancelling in-flight search tasks if they are
+ * breaching resource usage limits when the node is in duress.
+ *
+ * @opensearch.internal
+ */
+public class SearchBackpressureService extends AbstractLifecycleComponent implements TaskCompletionListener {
+    private static final Logger logger = LogManager.getLogger(SearchBackpressureService.class);
+
+    private volatile Scheduler.Cancellable scheduledFuture;
+
+    private final SearchBackpressureSettings settings;
+    private final TaskResourceTrackingService taskResourceTrackingService;
+    private final ThreadPool threadPool;
+    private final LongSupplier timeNanosSupplier;
+
+    private final List<NodeDuressTracker> nodeDuressTrackers;
+    private final Map<Class<? extends SearchBackpressureTask>, List<TaskResourceUsageTracker>> taskTrackers;
+
+    private final Map<Class<? extends SearchBackpressureTask>, SearchBackpressureState> searchBackpressureStates;
+    private final TaskManager taskManager;
+
+    public SearchBackpressureService(
+        SearchBackpressureSettings settings,
+        TaskResourceTrackingService taskResourceTrackingService,
+        ThreadPool threadPool,
+        TaskManager taskManager
+    ) {
+        this(
+            settings,
+            taskResourceTrackingService,
+            threadPool,
+            System::nanoTime,
+            List.of(
+                new NodeDuressTracker(
+                    () -> ProcessProbe.getInstance().getProcessCpuPercent() / 100.0 >= settings.getNodeDuressSettings().getCpuThreshold()
+                ),
+                new NodeDuressTracker(
+                    () -> JvmStats.jvmStats().getMem().getHeapUsedPercent() / 100.0 >= settings.getNodeDuressSettings().getHeapThreshold()
+                )
+            ),
+            getTrackers(
+                settings.getSearchTaskSettings()::getCpuTimeNanosThreshold,
+                settings.getSearchTaskSettings()::getHeapVarianceThreshold,
+                settings.getSearchTaskSettings()::getHeapPercentThreshold,
+                settings.getSearchTaskSettings().getHeapMovingAverageWindowSize(),
+                settings.getSearchTaskSettings()::getElapsedTimeNanosThreshold,
+                settings.getClusterSettings(),
+                SearchTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE
+            ),
+            getTrackers(
+                settings.getSearchShardTaskSettings()::getCpuTimeNanosThreshold,
+                settings.getSearchShardTaskSettings()::getHeapVarianceThreshold,
+                settings.getSearchShardTaskSettings()::getHeapPercentThreshold,
+                settings.getSearchShardTaskSettings().getHeapMovingAverageWindowSize(),
+                settings.getSearchShardTaskSettings()::getElapsedTimeNanosThreshold,
+                settings.getClusterSettings(),
+                SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE
+            ),
+            taskManager
+        );
+    }
+
+    public SearchBackpressureService(
+        SearchBackpressureSettings settings,
+        TaskResourceTrackingService taskResourceTrackingService,
+        ThreadPool threadPool,
+        LongSupplier timeNanosSupplier,
+        List<NodeDuressTracker> nodeDuressTrackers,
+        List<TaskResourceUsageTracker> searchTaskTrackers,
+        List<TaskResourceUsageTracker> searchShardTaskTrackers,
+        TaskManager taskManager
+    ) {
+        this.settings = settings;
+        this.taskResourceTrackingService = taskResourceTrackingService;
+        this.taskResourceTrackingService.addTaskCompletionListener(this);
+        this.threadPool = threadPool;
+        this.timeNanosSupplier = timeNanosSupplier;
+        this.nodeDuressTrackers = nodeDuressTrackers;
+        this.taskManager = taskManager;
+
+        this.searchBackpressureStates = Map.of(
+            SearchTask.class,
+            new SearchBackpressureState(
+                timeNanosSupplier,
+                getSettings().getSearchTaskSettings().getCancellationRateNanos(),
+                getSettings().getSearchTaskSettings().getCancellationBurst(),
+                getSettings().getSearchTaskSettings().getCancellationRatio()
+            ),
+            SearchShardTask.class,
+            new SearchBackpressureState(
+                timeNanosSupplier,
+                getSettings().getSearchShardTaskSettings().getCancellationRateNanos(),
+                getSettings().getSearchShardTaskSettings().getCancellationBurst(),
+                getSettings().getSearchShardTaskSettings().getCancellationRatio()
+            )
+        );
+        this.settings.getSearchTaskSettings().addListener(searchBackpressureStates.get(SearchTask.class));
+        this.settings.getSearchShardTaskSettings().addListener(searchBackpressureStates.get(SearchShardTask.class));
+
+        this.taskTrackers = Map.of(SearchTask.class, searchTaskTrackers, SearchShardTask.class, searchShardTaskTrackers);
+    }
+
+    void doRun() {
+        SearchBackpressureMode mode = getSettings().getMode();
+        if (mode == SearchBackpressureMode.DISABLED) {
+            return;
+        }
+
+        if (isNodeInDuress() == false) {
+            return;
+        }
+
+        List<CancellableTask> searchTasks = getTaskByType(SearchTask.class);
+        List<CancellableTask> searchShardTasks = getTaskByType(SearchShardTask.class);
+        List<CancellableTask> cancellableTasks = new ArrayList<>();
+
+        // Force-refresh usage stats of these tasks before making a cancellation decision.
+        taskResourceTrackingService.refreshResourceStats(searchTasks.toArray(new Task[0]));
+        taskResourceTrackingService.refreshResourceStats(searchShardTasks.toArray(new Task[0]));
+
+        // Check if increase in heap usage is due to SearchTasks
+        if (HeapUsageTracker.isHeapUsageDominatedBySearch(
+            searchTasks,
+            getSettings().getSearchTaskSettings().getTotalHeapPercentThreshold()
+        )) {
+            cancellableTasks.addAll(searchTasks);
+        }
+
+        // Check if increase in heap usage is due to SearchShardTasks
+        if (HeapUsageTracker.isHeapUsageDominatedBySearch(
+            searchShardTasks,
+            getSettings().getSearchShardTaskSettings().getTotalHeapPercentThreshold()
+        )) {
+            cancellableTasks.addAll(searchShardTasks);
+        }
+
+        // none of the task type is breaching the heap usage thresholds and hence we do not cancel any tasks
+        if (cancellableTasks.isEmpty()) {
+            return;
+        }
+
+        for (TaskCancellation taskCancellation : getTaskCancellations(cancellableTasks)) {
+            logger.warn(
+                "[{} mode] cancelling task [{}] due to high resource consumption [{}]",
+                mode.getName(),
+                taskCancellation.getTask().getId(),
+                taskCancellation.getReasonString()
+            );
+
+            if (mode != SearchBackpressureMode.ENFORCED) {
+                continue;
+            }
+
+            Class<? extends SearchBackpressureTask> taskType = getTaskType(taskCancellation.getTask());
+
+            // Independently remove tokens from both token buckets.
+            SearchBackpressureState searchBackpressureState = searchBackpressureStates.get(taskType);
+            boolean rateLimitReached = searchBackpressureState.getRateLimiter().request() == false;
+            boolean ratioLimitReached = searchBackpressureState.getRatioLimiter().request() == false;
+
+            // Stop cancelling tasks if there are no tokens in either of the two token buckets.
+            if (rateLimitReached && ratioLimitReached) {
+                logger.debug("task cancellation limit reached");
+                searchBackpressureState.incrementLimitReachedCount();
+                break;
+            }
+
+            taskCancellation.cancelTaskAndDescendants(taskManager);
+        }
+    }
+
+    /**
+     * Given a task, returns the type of the task
+     */
+    Class<? extends SearchBackpressureTask> getTaskType(Task task) {
+        if (task instanceof SearchTask) {
+            return SearchTask.class;
+        } else if (task instanceof SearchShardTask) {
+            return SearchShardTask.class;
+        } else {
+            throw new IllegalArgumentException("task must be instance of either SearchTask or SearchShardTask");
+        }
+    }
+
+    /**
+     * Returns true if the node is in duress consecutively for the past 'n' observations.
+     */
+    boolean isNodeInDuress() {
+        boolean isNodeInDuress = false;
+        int numSuccessiveBreaches = getSettings().getNodeDuressSettings().getNumSuccessiveBreaches();
+
+        for (NodeDuressTracker tracker : nodeDuressTrackers) {
+            if (tracker.check() >= numSuccessiveBreaches) {
+                isNodeInDuress = true;  // not breaking the loop so that each tracker's streak gets updated.
+            }
+        }
+
+        return isNodeInDuress;
+    }
+
+    /**
+     * Returns true if the increase in heap usage is due to search requests.
+     */
+
+    /**
+     * Filters and returns the list of currently running tasks of specified type.
+     */
+    <T extends CancellableTask & SearchBackpressureTask> List<CancellableTask> getTaskByType(Class<T> type) {
+        return taskResourceTrackingService.getResourceAwareTasks()
+            .values()
+            .stream()
+            .filter(type::isInstance)
+            .map(type::cast)
+            .collect(Collectors.toUnmodifiableList());
+    }
+
+    /**
+     * Returns a TaskCancellation wrapper containing the list of reasons (possibly zero), along with an overall
+     * cancellation score for the given task. Cancelling a task with a higher score has better chance of recovering the
+     * node from duress.
+     */
+    TaskCancellation getTaskCancellation(CancellableTask task) {
+        List<TaskCancellation.Reason> reasons = new ArrayList<>();
+        List<Runnable> callbacks = new ArrayList<>();
+        Class<? extends SearchBackpressureTask> taskType = getTaskType(task);
+        List<TaskResourceUsageTracker> trackers = taskTrackers.get(taskType);
+        for (TaskResourceUsageTracker tracker : trackers) {
+            Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+            if (reason.isPresent()) {
+                callbacks.add(tracker::incrementCancellations);
+                reasons.add(reason.get());
+            }
+        }
+        callbacks.add(searchBackpressureStates.get(taskType)::incrementCancellationCount);
+
+        return new TaskCancellation(task, reasons, callbacks);
+    }
+
+    /**
+     * Returns a list of TaskCancellations sorted by descending order of their cancellation scores.
+     */
+    List<TaskCancellation> getTaskCancellations(List<? extends CancellableTask> tasks) {
+        return tasks.stream()
+            .map(this::getTaskCancellation)
+            .filter(TaskCancellation::isEligibleForCancellation)
+            .sorted(Comparator.reverseOrder())
+            .collect(Collectors.toUnmodifiableList());
+    }
+
+    SearchBackpressureSettings getSettings() {
+        return settings;
+    }
+
+    SearchBackpressureState getSearchBackpressureState(Class<? extends SearchBackpressureTask> taskType) {
+        return searchBackpressureStates.get(taskType);
+    }
+
+    /**
+     * Given the threshold suppliers, returns the list of applicable trackers
+     */
+    public static List<TaskResourceUsageTracker> getTrackers(
+        LongSupplier cpuThresholdSupplier,
+        DoubleSupplier heapVarianceSupplier,
+        DoubleSupplier heapPercentThresholdSupplier,
+        int heapMovingAverageWindowSize,
+        LongSupplier ElapsedTimeNanosSupplier,
+        ClusterSettings clusterSettings,
+        Setting<Integer> windowSizeSetting
+    ) {
+        List<TaskResourceUsageTracker> trackers = new ArrayList<>();
+        trackers.add(new CpuUsageTracker(cpuThresholdSupplier));
+        if (isHeapTrackingSupported()) {
+            trackers.add(
+                new HeapUsageTracker(
+                    heapVarianceSupplier,
+                    heapPercentThresholdSupplier,
+                    heapMovingAverageWindowSize,
+                    clusterSettings,
+                    windowSizeSetting
+                )
+            );
+        } else {
+            logger.warn("heap size couldn't be determined");
+        }
+        trackers.add(new ElapsedTimeTracker(ElapsedTimeNanosSupplier, System::nanoTime));
+        return Collections.unmodifiableList(trackers);
+    }
+
+    @Override
+    public void onTaskCompleted(Task task) {
+        if (getSettings().getMode() == SearchBackpressureMode.DISABLED) {
+            return;
+        }
+
+        if (task instanceof SearchBackpressureTask == false) {
+            return;
+        }
+
+        CancellableTask cancellableTask = (CancellableTask) task;
+        Class<? extends SearchBackpressureTask> taskType = getTaskType(task);
+        if (cancellableTask.isCancelled() == false) {
+            searchBackpressureStates.get(taskType).incrementCompletionCount();
+        }
+
+        List<Exception> exceptions = new ArrayList<>();
+        List<TaskResourceUsageTracker> trackers = taskTrackers.get(taskType);
+        for (TaskResourceUsageTracker tracker : trackers) {
+            try {
+                tracker.update(task);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+    }
+
+    @Override
+    protected void doStart() {
+        scheduledFuture = threadPool.scheduleWithFixedDelay(() -> {
+            try {
+                doRun();
+            } catch (Exception e) {
+                logger.debug("failure in search search backpressure", e);
+            }
+        }, getSettings().getInterval(), ThreadPool.Names.GENERIC);
+    }
+
+    @Override
+    protected void doStop() {
+        if (scheduledFuture != null) {
+            scheduledFuture.cancel();
+        }
+    }
+
+    @Override
+    protected void doClose() throws IOException {}
+
+    public SearchBackpressureStats nodeStats() {
+        List<CancellableTask> searchTasks = getTaskByType(SearchTask.class);
+        List<CancellableTask> searchShardTasks = getTaskByType(SearchShardTask.class);
+        SearchTaskStats searchTaskStats = new SearchTaskStats(
+            searchBackpressureStates.get(SearchTask.class).getCancellationCount(),
+            searchBackpressureStates.get(SearchTask.class).getLimitReachedCount(),
+            taskTrackers.get(SearchTask.class)
+                .stream()
+                .collect(Collectors.toUnmodifiableMap(t -> TaskResourceUsageTrackerType.fromName(t.name()), t -> t.stats(searchTasks)))
+        );
+
+        SearchShardTaskStats searchShardTaskStats = new SearchShardTaskStats(
+            searchBackpressureStates.get(SearchShardTask.class).getCancellationCount(),
+            searchBackpressureStates.get(SearchShardTask.class).getLimitReachedCount(),
+            taskTrackers.get(SearchShardTask.class)
+                .stream()
+                .collect(Collectors.toUnmodifiableMap(t -> TaskResourceUsageTrackerType.fromName(t.name()), t -> t.stats(searchShardTasks)))
+        );
+
+        return new SearchBackpressureStats(searchTaskStats, searchShardTaskStats, getSettings().getMode());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureState.java b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureState.java
new file mode 100644
index 0000000000000..5f086bd498036
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/SearchBackpressureState.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+import org.opensearch.common.util.TokenBucket;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.LongSupplier;
+
+/**
+ * Tracks the current state of task completions and cancellations.
+ *
+ * @opensearch.internal
+ */
+public class SearchBackpressureState implements CancellationSettingsListener {
+    private final AtomicReference<TokenBucket> rateLimiter;
+    private final AtomicReference<TokenBucket> ratioLimiter;
+    private final LongSupplier timeNanosSupplier;
+    /**
+     * The number of successful task completions.
+     */
+    private final AtomicLong completionCount = new AtomicLong();
+    /**
+     * The number of task cancellations due to limit breaches.
+     */
+    private final AtomicLong cancellationCount = new AtomicLong();
+    /**
+     * The number of times task cancellation limit was reached.
+     */
+    private final AtomicLong limitReachedCount = new AtomicLong();
+    private volatile double cancellationBurst;
+    private volatile double cancellationRate;
+    private volatile double cancellationRatio;
+
+    SearchBackpressureState(
+        LongSupplier timeNanosSupplier,
+        double cancellationRateNanos,
+        double cancellationBurst,
+        double cancellationRatio
+    ) {
+        rateLimiter = new AtomicReference<>(new TokenBucket(timeNanosSupplier, cancellationRateNanos, cancellationBurst));
+        ratioLimiter = new AtomicReference<>(new TokenBucket(this::getCompletionCount, cancellationRatio, cancellationBurst));
+        this.timeNanosSupplier = timeNanosSupplier;
+        this.cancellationBurst = cancellationBurst;
+    }
+
+    public long getCompletionCount() {
+        return completionCount.get();
+    }
+
+    long incrementCompletionCount() {
+        return completionCount.incrementAndGet();
+    }
+
+    public long getCancellationCount() {
+        return cancellationCount.get();
+    }
+
+    long incrementCancellationCount() {
+        return cancellationCount.incrementAndGet();
+    }
+
+    public long getLimitReachedCount() {
+        return limitReachedCount.get();
+    }
+
+    long incrementLimitReachedCount() {
+        return limitReachedCount.incrementAndGet();
+    }
+
+    public TokenBucket getRateLimiter() {
+        return rateLimiter.get();
+    }
+
+    public TokenBucket getRatioLimiter() {
+        return ratioLimiter.get();
+    }
+
+    @Override
+    public void onRatioChanged(double ratio) {
+        this.cancellationRatio = ratio;
+        ratioLimiter.set(new TokenBucket(this::getCompletionCount, cancellationRatio, cancellationBurst));
+    }
+
+    @Override
+    public void onRateChanged(double rate) {
+        this.cancellationRate = rate;
+        rateLimiter.set(new TokenBucket(timeNanosSupplier, cancellationRate, cancellationBurst));
+    }
+
+    @Override
+    public void onBurstChanged(double burst) {
+        this.cancellationBurst = burst;
+        onRateChanged(cancellationRate);
+        onRatioChanged(cancellationRatio);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/package-info.java b/server/src/main/java/org/opensearch/search/backpressure/package-info.java
new file mode 100644
index 0000000000000..36d216993b2fc
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes responsible for search backpressure.
+ */
+package org.opensearch.search.backpressure;
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/NodeDuressSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/NodeDuressSettings.java
new file mode 100644
index 0000000000000..09c1e4fcef46c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/NodeDuressSettings.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+
+/**
+ * Defines the settings for a node to be considered in duress.
+ *
+ * @opensearch.internal
+ */
+public class NodeDuressSettings {
+    private static class Defaults {
+        private static final int NUM_SUCCESSIVE_BREACHES = 3;
+        private static final double CPU_THRESHOLD = 0.9;
+        private static final double HEAP_THRESHOLD = 0.7;
+    }
+
+    /**
+     * Defines the number of successive limit breaches after the node is marked "in duress".
+     */
+    private volatile int numSuccessiveBreaches;
+    public static final Setting<Integer> SETTING_NUM_SUCCESSIVE_BREACHES = Setting.intSetting(
+        "search_backpressure.node_duress.num_successive_breaches",
+        Defaults.NUM_SUCCESSIVE_BREACHES,
+        1,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the CPU usage threshold (in percentage) for a node to be considered "in duress".
+     */
+    private volatile double cpuThreshold;
+    public static final Setting<Double> SETTING_CPU_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.node_duress.cpu_threshold",
+        Defaults.CPU_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage threshold (in percentage) for a node to be considered "in duress".
+     */
+    private volatile double heapThreshold;
+    public static final Setting<Double> SETTING_HEAP_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.node_duress.heap_threshold",
+        Defaults.HEAP_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public NodeDuressSettings(Settings settings, ClusterSettings clusterSettings) {
+        numSuccessiveBreaches = SETTING_NUM_SUCCESSIVE_BREACHES.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_NUM_SUCCESSIVE_BREACHES, this::setNumSuccessiveBreaches);
+
+        cpuThreshold = SETTING_CPU_THRESHOLD.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CPU_THRESHOLD, this::setCpuThreshold);
+
+        heapThreshold = SETTING_HEAP_THRESHOLD.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_THRESHOLD, this::setHeapThreshold);
+    }
+
+    public int getNumSuccessiveBreaches() {
+        return numSuccessiveBreaches;
+    }
+
+    private void setNumSuccessiveBreaches(int numSuccessiveBreaches) {
+        this.numSuccessiveBreaches = numSuccessiveBreaches;
+    }
+
+    public double getCpuThreshold() {
+        return cpuThreshold;
+    }
+
+    private void setCpuThreshold(double cpuThreshold) {
+        this.cpuThreshold = cpuThreshold;
+    }
+
+    public double getHeapThreshold() {
+        return heapThreshold;
+    }
+
+    private void setHeapThreshold(double heapThreshold) {
+        this.heapThreshold = heapThreshold;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureMode.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureMode.java
new file mode 100644
index 0000000000000..72b58f1d3de02
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureMode.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import java.util.Locale;
+
+/**
+ * Defines the search backpressure mode.
+ */
+public enum SearchBackpressureMode {
+    /**
+     * SearchBackpressureService is completely disabled.
+     */
+    DISABLED("disabled"),
+
+    /**
+     * SearchBackpressureService only monitors the resource usage of running tasks.
+     */
+    MONITOR_ONLY("monitor_only"),
+
+    /**
+     * SearchBackpressureService monitors and rejects tasks that exceed resource usage thresholds.
+     */
+    ENFORCED("enforced");
+
+    private final String name;
+
+    SearchBackpressureMode(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public static SearchBackpressureMode fromName(String name) {
+        switch (name.toLowerCase(Locale.ROOT)) {
+            case "disabled":
+                return DISABLED;
+            case "monitor_only":
+                return MONITOR_ONLY;
+            case "enforced":
+                return ENFORCED;
+        }
+
+        throw new IllegalArgumentException("Invalid SearchBackpressureMode: " + name);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettings.java
new file mode 100644
index 0000000000000..d20e3e50d419f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettings.java
@@ -0,0 +1,155 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+
+/**
+ * Settings related to search backpressure mode and interval
+ *
+ * @opensearch.internal
+ */
+public class SearchBackpressureSettings {
+    private static class Defaults {
+        private static final long INTERVAL_MILLIS = 1000;
+        private static final String MODE = "monitor_only";
+
+        private static final double CANCELLATION_RATIO = 0.1;
+        private static final double CANCELLATION_RATE = 0.003;
+        private static final double CANCELLATION_BURST = 10.0;
+    }
+
+    /**
+     * Defines the interval (in millis) at which the SearchBackpressureService monitors and cancels tasks.
+     */
+    private final TimeValue interval;
+    public static final Setting<Long> SETTING_INTERVAL_MILLIS = Setting.longSetting(
+        "search_backpressure.interval_millis",
+        Defaults.INTERVAL_MILLIS,
+        1,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the search backpressure mode. It can be either "disabled", "monitor_only" or "enforced".
+     */
+    private volatile SearchBackpressureMode mode;
+    public static final Setting<SearchBackpressureMode> SETTING_MODE = new Setting<>(
+        "search_backpressure.mode",
+        Defaults.MODE,
+        SearchBackpressureMode::fromName,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the percentage of tasks to cancel relative to the number of successful task completions.
+     * In other words, it is the number of tokens added to the bucket on each successful task completion.
+     *
+     * The setting below is deprecated.
+     * To keep backwards compatibility, the old usage is remained, and it's also used as the fallback for the new usage.
+     */
+    public static final Setting<Double> SETTING_CANCELLATION_RATIO = Setting.doubleSetting(
+        "search_backpressure.cancellation_ratio",
+        Defaults.CANCELLATION_RATIO,
+        0.0,
+        1.0,
+        Setting.Property.Deprecated,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the number of tasks to cancel per unit time (in millis).
+     * In other words, it is the number of tokens added to the bucket each millisecond.
+     *
+     * The setting below is deprecated.
+     * To keep backwards compatibility, the old usage is remained, and it's also used as the fallback for the new usage.
+     */
+    public static final Setting<Double> SETTING_CANCELLATION_RATE = Setting.doubleSetting(
+        "search_backpressure.cancellation_rate",
+        Defaults.CANCELLATION_RATE,
+        0.0,
+        Setting.Property.Deprecated,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the maximum number of tasks that can be cancelled before being rate-limited.
+     *
+     * The setting below is deprecated.
+     * To keep backwards compatibility, the old usage is remained, and it's also used as the fallback for the new usage.
+     */
+    public static final Setting<Double> SETTING_CANCELLATION_BURST = Setting.doubleSetting(
+        "search_backpressure.cancellation_burst",
+        Defaults.CANCELLATION_BURST,
+        1.0,
+        Setting.Property.Deprecated,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private final Settings settings;
+    private final ClusterSettings clusterSettings;
+    private final NodeDuressSettings nodeDuressSettings;
+    private final SearchTaskSettings searchTaskSettings;
+    private final SearchShardTaskSettings searchShardTaskSettings;
+
+    public SearchBackpressureSettings(Settings settings, ClusterSettings clusterSettings) {
+        this.settings = settings;
+        this.clusterSettings = clusterSettings;
+        this.nodeDuressSettings = new NodeDuressSettings(settings, clusterSettings);
+        this.searchTaskSettings = new SearchTaskSettings(settings, clusterSettings);
+        this.searchShardTaskSettings = new SearchShardTaskSettings(settings, clusterSettings);
+
+        interval = new TimeValue(SETTING_INTERVAL_MILLIS.get(settings));
+
+        mode = SETTING_MODE.get(settings);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_MODE, this::setMode);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATIO, searchShardTaskSettings::setCancellationRatio);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATE, searchShardTaskSettings::setCancellationRate);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_BURST, searchShardTaskSettings::setCancellationBurst);
+    }
+
+    public Settings getSettings() {
+        return settings;
+    }
+
+    public ClusterSettings getClusterSettings() {
+        return clusterSettings;
+    }
+
+    public NodeDuressSettings getNodeDuressSettings() {
+        return nodeDuressSettings;
+    }
+
+    public SearchTaskSettings getSearchTaskSettings() {
+        return searchTaskSettings;
+    }
+
+    public SearchShardTaskSettings getSearchShardTaskSettings() {
+        return searchShardTaskSettings;
+    }
+
+    public TimeValue getInterval() {
+        return interval;
+    }
+
+    public SearchBackpressureMode getMode() {
+        return mode;
+    }
+
+    public void setMode(SearchBackpressureMode mode) {
+        this.mode = mode;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java
new file mode 100644
index 0000000000000..105023a20173f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchShardTaskSettings.java
@@ -0,0 +1,277 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.search.backpressure.CancellationSettingsListener;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+/**
+ * Defines the settings related to the cancellation of SearchShardTasks.
+ *
+ * @opensearch.internal
+ */
+public class SearchShardTaskSettings {
+    private final List<CancellationSettingsListener> listeners = new ArrayList<>();
+    private final ClusterSettings clusterSettings;
+
+    private static class Defaults {
+        private static final double CANCELLATION_RATIO = 0.1;
+        private static final double CANCELLATION_RATE = 0.003;
+        private static final double CANCELLATION_BURST = 10.0;
+        private static final double TOTAL_HEAP_PERCENT_THRESHOLD = 0.05;
+        private static final long CPU_TIME_MILLIS_THRESHOLD = 15000;
+        private static final long ELAPSED_TIME_MILLIS_THRESHOLD = 30000;
+        private static final double HEAP_PERCENT_THRESHOLD = 0.005;
+        private static final double HEAP_VARIANCE_THRESHOLD = 2.0;
+        private static final int HEAP_MOVING_AVERAGE_WINDOW_SIZE = 100;
+    }
+
+    /**
+     * Defines the percentage of SearchShardTasks to cancel relative to the number of successful SearchShardTasks completions.
+     * In other words, it is the number of tokens added to the bucket on each successful SearchShardTask completion.
+     */
+    private volatile double cancellationRatio;
+    public static final Setting<Double> SETTING_CANCELLATION_RATIO = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.cancellation_ratio",
+        SearchBackpressureSettings.SETTING_CANCELLATION_RATIO,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the number of SearchShardTasks to cancel per unit time (in millis).
+     * In other words, it is the number of tokens added to the bucket each millisecond.
+     */
+    private volatile double cancellationRate;
+    public static final Setting<Double> SETTING_CANCELLATION_RATE = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.cancellation_rate",
+        SearchBackpressureSettings.SETTING_CANCELLATION_RATE,
+        0.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the maximum number of SearchShardTasks that can be cancelled before being rate-limited.
+     */
+    private volatile double cancellationBurst;
+    public static final Setting<Double> SETTING_CANCELLATION_BURST = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.cancellation_burst",
+        SearchBackpressureSettings.SETTING_CANCELLATION_BURST,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage threshold (in percentage) for the sum of heap usages across all search shard tasks
+     * before in-flight cancellation is applied.
+     */
+    private volatile double totalHeapPercentThreshold;
+    public static final Setting<Double> SETTING_TOTAL_HEAP_PERCENT_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.total_heap_percent_threshold",
+        Defaults.TOTAL_HEAP_PERCENT_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the CPU usage threshold (in millis) for an individual search shard task before it is considered for cancellation.
+     */
+    private volatile long cpuTimeMillisThreshold;
+    public static final Setting<Long> SETTING_CPU_TIME_MILLIS_THRESHOLD = Setting.longSetting(
+        "search_backpressure.search_shard_task.cpu_time_millis_threshold",
+        Defaults.CPU_TIME_MILLIS_THRESHOLD,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the elapsed time threshold (in millis) for an individual search shard task before it is considered for cancellation.
+     */
+    private volatile long elapsedTimeMillisThreshold;
+    public static final Setting<Long> SETTING_ELAPSED_TIME_MILLIS_THRESHOLD = Setting.longSetting(
+        "search_backpressure.search_shard_task.elapsed_time_millis_threshold",
+        Defaults.ELAPSED_TIME_MILLIS_THRESHOLD,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage threshold (in percentage) for an individual search shard task before it is considered for cancellation.
+     */
+    private volatile double heapPercentThreshold;
+    public static final Setting<Double> SETTING_HEAP_PERCENT_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.heap_percent_threshold",
+        Defaults.HEAP_PERCENT_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage variance for an individual search shard task before it is considered for cancellation.
+     * A task is considered for cancellation when taskHeapUsage is greater than or equal to heapUsageMovingAverage * variance.
+     */
+    private volatile double heapVarianceThreshold;
+    public static final Setting<Double> SETTING_HEAP_VARIANCE_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_shard_task.heap_variance",
+        Defaults.HEAP_VARIANCE_THRESHOLD,
+        0.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the window size to calculate the moving average of heap usage of completed search shard tasks.
+     */
+    private volatile int heapMovingAverageWindowSize;
+    public static final Setting<Integer> SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE = Setting.intSetting(
+        "search_backpressure.search_shard_task.heap_moving_average_window_size",
+        Defaults.HEAP_MOVING_AVERAGE_WINDOW_SIZE,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public SearchShardTaskSettings(Settings settings, ClusterSettings clusterSettings) {
+        totalHeapPercentThreshold = SETTING_TOTAL_HEAP_PERCENT_THRESHOLD.get(settings);
+        this.cpuTimeMillisThreshold = SETTING_CPU_TIME_MILLIS_THRESHOLD.get(settings);
+        this.elapsedTimeMillisThreshold = SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.get(settings);
+        this.heapPercentThreshold = SETTING_HEAP_PERCENT_THRESHOLD.get(settings);
+        this.heapVarianceThreshold = SETTING_HEAP_VARIANCE_THRESHOLD.get(settings);
+        this.heapMovingAverageWindowSize = SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.get(settings);
+        this.cancellationRatio = SETTING_CANCELLATION_RATIO.get(settings);
+        this.cancellationRate = SETTING_CANCELLATION_RATE.get(settings);
+        this.cancellationBurst = SETTING_CANCELLATION_BURST.get(settings);
+        this.clusterSettings = clusterSettings;
+
+        clusterSettings.addSettingsUpdateConsumer(SETTING_TOTAL_HEAP_PERCENT_THRESHOLD, this::setTotalHeapPercentThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CPU_TIME_MILLIS_THRESHOLD, this::setCpuTimeMillisThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_ELAPSED_TIME_MILLIS_THRESHOLD, this::setElapsedTimeMillisThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_PERCENT_THRESHOLD, this::setHeapPercentThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_VARIANCE_THRESHOLD, this::setHeapVarianceThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE, this::setHeapMovingAverageWindowSize);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATIO, this::setCancellationRatio);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATE, this::setCancellationRate);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_BURST, this::setCancellationBurst);
+    }
+
+    public double getTotalHeapPercentThreshold() {
+        return totalHeapPercentThreshold;
+    }
+
+    public long getCpuTimeNanosThreshold() {
+        return TimeUnit.MILLISECONDS.toNanos(cpuTimeMillisThreshold);
+    }
+
+    public long getElapsedTimeNanosThreshold() {
+        return TimeUnit.MILLISECONDS.toNanos(elapsedTimeMillisThreshold);
+    }
+
+    public double getHeapPercentThreshold() {
+        return heapPercentThreshold;
+    }
+
+    public double getHeapVarianceThreshold() {
+        return heapVarianceThreshold;
+    }
+
+    public int getHeapMovingAverageWindowSize() {
+        return heapMovingAverageWindowSize;
+    }
+
+    public void setTotalHeapPercentThreshold(double totalHeapPercentThreshold) {
+        this.totalHeapPercentThreshold = totalHeapPercentThreshold;
+    }
+
+    public void setCpuTimeMillisThreshold(long cpuTimeMillisThreshold) {
+        this.cpuTimeMillisThreshold = cpuTimeMillisThreshold;
+    }
+
+    public void setElapsedTimeMillisThreshold(long elapsedTimeMillisThreshold) {
+        this.elapsedTimeMillisThreshold = elapsedTimeMillisThreshold;
+    }
+
+    public void setHeapPercentThreshold(double heapPercentThreshold) {
+        this.heapPercentThreshold = heapPercentThreshold;
+    }
+
+    public void setHeapVarianceThreshold(double heapVarianceThreshold) {
+        this.heapVarianceThreshold = heapVarianceThreshold;
+    }
+
+    public void setHeapMovingAverageWindowSize(int heapMovingAverageWindowSize) {
+        this.heapMovingAverageWindowSize = heapMovingAverageWindowSize;
+    }
+
+    public double getCancellationRatio() {
+        return cancellationRatio;
+    }
+
+    void setCancellationRatio(double cancellationRatio) {
+        this.cancellationRatio = cancellationRatio;
+        notifyListeners(listener -> listener.onRatioChanged(cancellationRatio));
+    }
+
+    public double getCancellationRate() {
+        return cancellationRate;
+    }
+
+    public double getCancellationRateNanos() {
+        return getCancellationRate() / TimeUnit.MILLISECONDS.toNanos(1); // rate per nanoseconds
+    }
+
+    void setCancellationRate(double cancellationRate) {
+        this.cancellationRate = cancellationRate;
+        notifyListeners(listener -> listener.onRateChanged(cancellationRate));
+    }
+
+    public double getCancellationBurst() {
+        return cancellationBurst;
+    }
+
+    void setCancellationBurst(double cancellationBurst) {
+        this.cancellationBurst = cancellationBurst;
+        notifyListeners(listener -> listener.onBurstChanged(cancellationBurst));
+    }
+
+    public void addListener(CancellationSettingsListener listener) {
+        listeners.add(listener);
+    }
+
+    private void notifyListeners(Consumer<CancellationSettingsListener> consumer) {
+        List<Exception> exceptions = new ArrayList<>();
+
+        for (CancellationSettingsListener listener : listeners) {
+            try {
+                consumer.accept(listener);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java
new file mode 100644
index 0000000000000..4b12eda9fb59d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/SearchTaskSettings.java
@@ -0,0 +1,278 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.search.backpressure.CancellationSettingsListener;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+/**
+ * Defines the settings related to the cancellation of SearchTasks.
+ *
+ * @opensearch.internal
+ */
+
+public class SearchTaskSettings {
+    private final List<CancellationSettingsListener> listeners = new ArrayList<>();
+    private final ClusterSettings clusterSettings;
+
+    private static class Defaults {
+        private static final double CANCELLATION_RATIO = 0.1;
+        private static final double CANCELLATION_RATE = 0.003;
+        private static final double CANCELLATION_BURST = 5.0;
+        private static final double TOTAL_HEAP_PERCENT_THRESHOLD = 0.05;
+        private static final long CPU_TIME_MILLIS_THRESHOLD = 30000;
+        private static final long ELAPSED_TIME_MILLIS_THRESHOLD = 45000;
+        private static final double HEAP_PERCENT_THRESHOLD = 0.02;
+        private static final double HEAP_VARIANCE_THRESHOLD = 2.0;
+        private static final int HEAP_MOVING_AVERAGE_WINDOW_SIZE = 100;
+    }
+
+    /**
+     * Defines the percentage of SearchTasks to cancel relative to the number of successful SearchTask completions.
+     * In other words, it is the number of tokens added to the bucket on each successful SearchTask completion.
+     */
+    private volatile double cancellationRatio;
+    public static final Setting<Double> SETTING_CANCELLATION_RATIO = Setting.doubleSetting(
+        "search_backpressure.search_task.cancellation_ratio",
+        Defaults.CANCELLATION_RATIO,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the number of SearchTasks to cancel per unit time (in millis).
+     * In other words, it is the number of tokens added to the bucket each millisecond.
+     */
+    private volatile double cancellationRate;
+    public static final Setting<Double> SETTING_CANCELLATION_RATE = Setting.doubleSetting(
+        "search_backpressure.search_task.cancellation_rate",
+        Defaults.CANCELLATION_RATE,
+        0.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the maximum number of SearchTasks that can be cancelled before being rate-limited.
+     */
+    private volatile double cancellationBurst;
+    public static final Setting<Double> SETTING_CANCELLATION_BURST = Setting.doubleSetting(
+        "search_backpressure.search_task.cancellation_burst",
+        Defaults.CANCELLATION_BURST,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage threshold (in percentage) for the sum of heap usages across all search tasks
+     * before in-flight cancellation is applied.
+     */
+    private volatile double totalHeapPercentThreshold;
+    public static final Setting<Double> SETTING_TOTAL_HEAP_PERCENT_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_task.total_heap_percent_threshold",
+        Defaults.TOTAL_HEAP_PERCENT_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the CPU usage threshold (in millis) for an individual search task before it is considered for cancellation.
+     */
+    private volatile long cpuTimeMillisThreshold;
+    public static final Setting<Long> SETTING_CPU_TIME_MILLIS_THRESHOLD = Setting.longSetting(
+        "search_backpressure.search_task.cpu_time_millis_threshold",
+        Defaults.CPU_TIME_MILLIS_THRESHOLD,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the elapsed time threshold (in millis) for an individual search task before it is considered for cancellation.
+     */
+    private volatile long elapsedTimeMillisThreshold;
+    public static final Setting<Long> SETTING_ELAPSED_TIME_MILLIS_THRESHOLD = Setting.longSetting(
+        "search_backpressure.search_task.elapsed_time_millis_threshold",
+        Defaults.ELAPSED_TIME_MILLIS_THRESHOLD,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage threshold (in percentage) for an individual search task before it is considered for cancellation.
+     */
+    private volatile double heapPercentThreshold;
+    public static final Setting<Double> SETTING_HEAP_PERCENT_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_task.heap_percent_threshold",
+        Defaults.HEAP_PERCENT_THRESHOLD,
+        0.0,
+        1.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the heap usage variance for an individual search task before it is considered for cancellation.
+     * A task is considered for cancellation when taskHeapUsage is greater than or equal to heapUsageMovingAverage * variance.
+     */
+    private volatile double heapVarianceThreshold;
+    public static final Setting<Double> SETTING_HEAP_VARIANCE_THRESHOLD = Setting.doubleSetting(
+        "search_backpressure.search_task.heap_variance",
+        Defaults.HEAP_VARIANCE_THRESHOLD,
+        0.0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Defines the window size to calculate the moving average of heap usage of completed search tasks.
+     */
+    private volatile int heapMovingAverageWindowSize;
+    public static final Setting<Integer> SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE = Setting.intSetting(
+        "search_backpressure.search_task.heap_moving_average_window_size",
+        Defaults.HEAP_MOVING_AVERAGE_WINDOW_SIZE,
+        0,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    public SearchTaskSettings(Settings settings, ClusterSettings clusterSettings) {
+        this.totalHeapPercentThreshold = SETTING_TOTAL_HEAP_PERCENT_THRESHOLD.get(settings);
+        this.cpuTimeMillisThreshold = SETTING_CPU_TIME_MILLIS_THRESHOLD.get(settings);
+        this.elapsedTimeMillisThreshold = SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.get(settings);
+        this.heapPercentThreshold = SETTING_HEAP_PERCENT_THRESHOLD.get(settings);
+        this.heapVarianceThreshold = SETTING_HEAP_VARIANCE_THRESHOLD.get(settings);
+        this.heapMovingAverageWindowSize = SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.get(settings);
+        this.cancellationRatio = SETTING_CANCELLATION_RATIO.get(settings);
+        this.cancellationRate = SETTING_CANCELLATION_RATE.get(settings);
+        this.cancellationBurst = SETTING_CANCELLATION_BURST.get(settings);
+        this.clusterSettings = clusterSettings;
+
+        clusterSettings.addSettingsUpdateConsumer(SETTING_TOTAL_HEAP_PERCENT_THRESHOLD, this::setTotalHeapPercentThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CPU_TIME_MILLIS_THRESHOLD, this::setCpuTimeMillisThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_ELAPSED_TIME_MILLIS_THRESHOLD, this::setElapsedTimeMillisThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_PERCENT_THRESHOLD, this::setHeapPercentThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_VARIANCE_THRESHOLD, this::setHeapVarianceThreshold);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE, this::setHeapMovingAverageWindowSize);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATIO, this::setCancellationRatio);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_RATE, this::setCancellationRate);
+        clusterSettings.addSettingsUpdateConsumer(SETTING_CANCELLATION_BURST, this::setCancellationBurst);
+    }
+
+    public double getTotalHeapPercentThreshold() {
+        return totalHeapPercentThreshold;
+    }
+
+    public long getCpuTimeNanosThreshold() {
+        return TimeUnit.MILLISECONDS.toNanos(cpuTimeMillisThreshold);
+    }
+
+    public long getElapsedTimeNanosThreshold() {
+        return TimeUnit.MILLISECONDS.toNanos(elapsedTimeMillisThreshold);
+    }
+
+    public double getHeapPercentThreshold() {
+        return heapPercentThreshold;
+    }
+
+    public double getHeapVarianceThreshold() {
+        return heapVarianceThreshold;
+    }
+
+    public int getHeapMovingAverageWindowSize() {
+        return heapMovingAverageWindowSize;
+    }
+
+    public void setTotalHeapPercentThreshold(double totalHeapPercentThreshold) {
+        this.totalHeapPercentThreshold = totalHeapPercentThreshold;
+    }
+
+    public void setCpuTimeMillisThreshold(long cpuTimeMillisThreshold) {
+        this.cpuTimeMillisThreshold = cpuTimeMillisThreshold;
+    }
+
+    public void setElapsedTimeMillisThreshold(long elapsedTimeMillisThreshold) {
+        this.elapsedTimeMillisThreshold = elapsedTimeMillisThreshold;
+    }
+
+    public void setHeapPercentThreshold(double heapPercentThreshold) {
+        this.heapPercentThreshold = heapPercentThreshold;
+    }
+
+    public void setHeapVarianceThreshold(double heapVarianceThreshold) {
+        this.heapVarianceThreshold = heapVarianceThreshold;
+    }
+
+    public void setHeapMovingAverageWindowSize(int heapMovingAverageWindowSize) {
+        this.heapMovingAverageWindowSize = heapMovingAverageWindowSize;
+    }
+
+    public double getCancellationRatio() {
+        return cancellationRatio;
+    }
+
+    private void setCancellationRatio(double cancellationRatio) {
+        this.cancellationRatio = cancellationRatio;
+        notifyListeners(listener -> listener.onRatioChanged(cancellationRatio));
+    }
+
+    public double getCancellationRate() {
+        return cancellationRate;
+    }
+
+    public double getCancellationRateNanos() {
+        return getCancellationRate() / TimeUnit.MILLISECONDS.toNanos(1); // rate per nanoseconds
+    }
+
+    private void setCancellationRate(double cancellationRate) {
+        this.cancellationRate = cancellationRate;
+        notifyListeners(listener -> listener.onRateChanged(cancellationRate));
+    }
+
+    public double getCancellationBurst() {
+        return cancellationBurst;
+    }
+
+    private void setCancellationBurst(double cancellationBurst) {
+        this.cancellationBurst = cancellationBurst;
+        notifyListeners(listener -> listener.onBurstChanged(cancellationBurst));
+    }
+
+    public void addListener(CancellationSettingsListener listener) {
+        listeners.add(listener);
+    }
+
+    private void notifyListeners(Consumer<CancellationSettingsListener> consumer) {
+        List<Exception> exceptions = new ArrayList<>();
+
+        for (CancellationSettingsListener listener : listeners) {
+            try {
+                consumer.accept(listener);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/settings/package-info.java b/server/src/main/java/org/opensearch/search/backpressure/settings/package-info.java
new file mode 100644
index 0000000000000..a853a139b096b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/settings/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains settings for search backpressure.
+ */
+package org.opensearch.search.backpressure.settings;
diff --git a/server/src/main/java/org/opensearch/search/backpressure/stats/SearchBackpressureStats.java b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchBackpressureStats.java
new file mode 100644
index 0000000000000..973ff735f82d2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchBackpressureStats.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.Version;
+import org.opensearch.common.Nullable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.backpressure.settings.SearchBackpressureMode;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Stats related to search backpressure.
+ */
+public class SearchBackpressureStats implements ToXContentFragment, Writeable {
+    private final SearchShardTaskStats searchShardTaskStats;
+    private final SearchBackpressureMode mode;
+    @Nullable
+    private final SearchTaskStats searchTaskStats;
+
+    public SearchBackpressureStats(
+        SearchTaskStats searchTaskStats,
+        SearchShardTaskStats searchShardTaskStats,
+        SearchBackpressureMode mode
+    ) {
+        this.searchShardTaskStats = searchShardTaskStats;
+        this.mode = mode;
+        this.searchTaskStats = searchTaskStats;
+    }
+
+    public SearchBackpressureStats(StreamInput in) throws IOException {
+        searchShardTaskStats = new SearchShardTaskStats(in);
+        mode = SearchBackpressureMode.fromName(in.readString());
+        if (in.getVersion().onOrAfter(Version.V_2_6_0)) {
+            searchTaskStats = in.readOptionalWriteable(SearchTaskStats::new);
+        } else {
+            searchTaskStats = null;
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject("search_backpressure");
+        if (searchTaskStats != null) {
+            builder.field("search_task", searchTaskStats);
+        }
+        builder.field("search_shard_task", searchShardTaskStats);
+        builder.field("mode", mode.getName());
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        searchShardTaskStats.writeTo(out);
+        out.writeString(mode.getName());
+        if (out.getVersion().onOrAfter(Version.V_2_6_0)) {
+            out.writeOptionalWriteable(searchTaskStats);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchBackpressureStats that = (SearchBackpressureStats) o;
+        return mode == that.mode
+            && Objects.equals(searchTaskStats, that.searchTaskStats)
+            && Objects.equals(searchShardTaskStats, that.searchShardTaskStats);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(searchTaskStats, searchShardTaskStats, mode);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/stats/SearchShardTaskStats.java b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchShardTaskStats.java
new file mode 100644
index 0000000000000..678c19d83fb96
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchShardTaskStats.java
@@ -0,0 +1,98 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.backpressure.trackers.CpuUsageTracker;
+import org.opensearch.search.backpressure.trackers.ElapsedTimeTracker;
+import org.opensearch.search.backpressure.trackers.HeapUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Stats related to cancelled SearchShardTasks.
+ */
+public class SearchShardTaskStats implements ToXContentObject, Writeable {
+    private final long cancellationCount;
+    private final long limitReachedCount;
+    private final Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats;
+
+    public SearchShardTaskStats(
+        long cancellationCount,
+        long limitReachedCount,
+        Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats
+    ) {
+        this.cancellationCount = cancellationCount;
+        this.limitReachedCount = limitReachedCount;
+        this.resourceUsageTrackerStats = resourceUsageTrackerStats;
+    }
+
+    public SearchShardTaskStats(StreamInput in) throws IOException {
+        this.cancellationCount = in.readVLong();
+        this.limitReachedCount = in.readVLong();
+
+        MapBuilder<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> builder = new MapBuilder<>();
+        builder.put(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER, in.readOptionalWriteable(CpuUsageTracker.Stats::new));
+        builder.put(TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER, in.readOptionalWriteable(HeapUsageTracker.Stats::new));
+        builder.put(TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER, in.readOptionalWriteable(ElapsedTimeTracker.Stats::new));
+        this.resourceUsageTrackerStats = builder.immutableMap();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+
+        builder.startObject("resource_tracker_stats");
+        for (Map.Entry<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> entry : resourceUsageTrackerStats.entrySet()) {
+            builder.field(entry.getKey().getName(), entry.getValue());
+        }
+        builder.endObject();
+
+        builder.startObject("cancellation_stats")
+            .field("cancellation_count", cancellationCount)
+            .field("cancellation_limit_reached_count", limitReachedCount)
+            .endObject();
+
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(cancellationCount);
+        out.writeVLong(limitReachedCount);
+
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER));
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER));
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER));
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchShardTaskStats that = (SearchShardTaskStats) o;
+        return cancellationCount == that.cancellationCount
+            && limitReachedCount == that.limitReachedCount
+            && resourceUsageTrackerStats.equals(that.resourceUsageTrackerStats);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(cancellationCount, limitReachedCount, resourceUsageTrackerStats);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/stats/SearchTaskStats.java b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchTaskStats.java
new file mode 100644
index 0000000000000..302350104bd3a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/stats/SearchTaskStats.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.backpressure.trackers.CpuUsageTracker;
+import org.opensearch.search.backpressure.trackers.ElapsedTimeTracker;
+import org.opensearch.search.backpressure.trackers.HeapUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Stats related to cancelled SearchTasks.
+ */
+
+public class SearchTaskStats implements ToXContentObject, Writeable {
+    private final long cancellationCount;
+    private final long limitReachedCount;
+    private final Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats;
+
+    public SearchTaskStats(
+        long cancellationCount,
+        long limitReachedCount,
+        Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats
+    ) {
+        this.cancellationCount = cancellationCount;
+        this.limitReachedCount = limitReachedCount;
+        this.resourceUsageTrackerStats = resourceUsageTrackerStats;
+    }
+
+    public SearchTaskStats(StreamInput in) throws IOException {
+        this.cancellationCount = in.readVLong();
+        this.limitReachedCount = in.readVLong();
+
+        MapBuilder<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> builder = new MapBuilder<>();
+        builder.put(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER, in.readOptionalWriteable(CpuUsageTracker.Stats::new));
+        builder.put(TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER, in.readOptionalWriteable(HeapUsageTracker.Stats::new));
+        builder.put(TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER, in.readOptionalWriteable(ElapsedTimeTracker.Stats::new));
+        this.resourceUsageTrackerStats = builder.immutableMap();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+
+        builder.startObject("resource_tracker_stats");
+        for (Map.Entry<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> entry : resourceUsageTrackerStats.entrySet()) {
+            builder.field(entry.getKey().getName(), entry.getValue());
+        }
+        builder.endObject();
+
+        builder.startObject("cancellation_stats")
+            .field("cancellation_count", cancellationCount)
+            .field("cancellation_limit_reached_count", limitReachedCount)
+            .endObject();
+
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(cancellationCount);
+        out.writeVLong(limitReachedCount);
+
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER));
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER));
+        out.writeOptionalWriteable(resourceUsageTrackerStats.get(TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER));
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchTaskStats that = (SearchTaskStats) o;
+        return cancellationCount == that.cancellationCount
+            && limitReachedCount == that.limitReachedCount
+            && resourceUsageTrackerStats.equals(that.resourceUsageTrackerStats);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(cancellationCount, limitReachedCount, resourceUsageTrackerStats);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/stats/package-info.java b/server/src/main/java/org/opensearch/search/backpressure/stats/package-info.java
new file mode 100644
index 0000000000000..514b274c2cf1a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/stats/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains models required for the search backpressure stats API response.
+ */
+package org.opensearch.search.backpressure.stats;
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/CpuUsageTracker.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/CpuUsageTracker.java
new file mode 100644
index 0000000000000..507953cb4a20e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/CpuUsageTracker.java
@@ -0,0 +1,120 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.util.function.LongSupplier;
+
+import static org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType.CPU_USAGE_TRACKER;
+
+/**
+ * CpuUsageTracker evaluates if the task has consumed too many CPU cycles than allowed.
+ *
+ * @opensearch.internal
+ */
+public class CpuUsageTracker extends TaskResourceUsageTracker {
+
+    private final LongSupplier thresholdSupplier;
+
+    public CpuUsageTracker(LongSupplier thresholdSupplier) {
+        this.thresholdSupplier = thresholdSupplier;
+    }
+
+    @Override
+    public String name() {
+        return CPU_USAGE_TRACKER.getName();
+    }
+
+    @Override
+    public Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task) {
+        long usage = task.getTotalResourceStats().getCpuTimeInNanos();
+        long threshold = thresholdSupplier.getAsLong();
+
+        if (usage < threshold) {
+            return Optional.empty();
+        }
+
+        return Optional.of(
+            new TaskCancellation.Reason(
+                "cpu usage exceeded ["
+                    + new TimeValue(usage, TimeUnit.NANOSECONDS)
+                    + " >= "
+                    + new TimeValue(threshold, TimeUnit.NANOSECONDS)
+                    + "]",
+                1  // TODO: fine-tune the cancellation score/weight
+            )
+        );
+    }
+
+    @Override
+    public TaskResourceUsageTracker.Stats stats(List<? extends Task> activeTasks) {
+        long currentMax = activeTasks.stream().mapToLong(t -> t.getTotalResourceStats().getCpuTimeInNanos()).max().orElse(0);
+        long currentAvg = (long) activeTasks.stream().mapToLong(t -> t.getTotalResourceStats().getCpuTimeInNanos()).average().orElse(0);
+        return new Stats(getCancellations(), currentMax, currentAvg);
+    }
+
+    /**
+     * Stats related to CpuUsageTracker.
+     */
+    public static class Stats implements TaskResourceUsageTracker.Stats {
+        private final long cancellationCount;
+        private final long currentMax;
+        private final long currentAvg;
+
+        public Stats(long cancellationCount, long currentMax, long currentAvg) {
+            this.cancellationCount = cancellationCount;
+            this.currentMax = currentMax;
+            this.currentAvg = currentAvg;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            this(in.readVLong(), in.readVLong(), in.readVLong());
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.startObject()
+                .field("cancellation_count", cancellationCount)
+                .humanReadableField("current_max_millis", "current_max", new TimeValue(currentMax, TimeUnit.NANOSECONDS))
+                .humanReadableField("current_avg_millis", "current_avg", new TimeValue(currentAvg, TimeUnit.NANOSECONDS))
+                .endObject();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeVLong(cancellationCount);
+            out.writeVLong(currentMax);
+            out.writeVLong(currentAvg);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Stats stats = (Stats) o;
+            return cancellationCount == stats.cancellationCount && currentMax == stats.currentMax && currentAvg == stats.currentAvg;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(cancellationCount, currentMax, currentAvg);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTracker.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTracker.java
new file mode 100644
index 0000000000000..f1e8abe7e3230
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTracker.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.util.function.LongSupplier;
+
+import static org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER;
+
+/**
+ * ElapsedTimeTracker evaluates if the task has been running for more time than allowed.
+ *
+ * @opensearch.internal
+ */
+public class ElapsedTimeTracker extends TaskResourceUsageTracker {
+    private final LongSupplier thresholdSupplier;
+    private final LongSupplier timeNanosSupplier;
+
+    public ElapsedTimeTracker(LongSupplier thresholdSupplier, LongSupplier timeNanosSupplier) {
+        this.thresholdSupplier = thresholdSupplier;
+        this.timeNanosSupplier = timeNanosSupplier;
+    }
+
+    @Override
+    public String name() {
+        return ELAPSED_TIME_TRACKER.getName();
+    }
+
+    @Override
+    public Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task) {
+        long usage = timeNanosSupplier.getAsLong() - task.getStartTimeNanos();
+        long threshold = thresholdSupplier.getAsLong();
+
+        if (usage < threshold) {
+            return Optional.empty();
+        }
+
+        return Optional.of(
+            new TaskCancellation.Reason(
+                "elapsed time exceeded ["
+                    + new TimeValue(usage, TimeUnit.NANOSECONDS)
+                    + " >= "
+                    + new TimeValue(threshold, TimeUnit.NANOSECONDS)
+                    + "]",
+                1  // TODO: fine-tune the cancellation score/weight
+            )
+        );
+    }
+
+    @Override
+    public TaskResourceUsageTracker.Stats stats(List<? extends Task> activeTasks) {
+        long now = timeNanosSupplier.getAsLong();
+        long currentMax = activeTasks.stream().mapToLong(t -> now - t.getStartTimeNanos()).max().orElse(0);
+        long currentAvg = (long) activeTasks.stream().mapToLong(t -> now - t.getStartTimeNanos()).average().orElse(0);
+        return new Stats(getCancellations(), currentMax, currentAvg);
+    }
+
+    /**
+     * Stats related to ElapsedTimeTracker.
+     */
+    public static class Stats implements TaskResourceUsageTracker.Stats {
+        private final long cancellationCount;
+        private final long currentMax;
+        private final long currentAvg;
+
+        public Stats(long cancellationCount, long currentMax, long currentAvg) {
+            this.cancellationCount = cancellationCount;
+            this.currentMax = currentMax;
+            this.currentAvg = currentAvg;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            this(in.readVLong(), in.readVLong(), in.readVLong());
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.startObject()
+                .field("cancellation_count", cancellationCount)
+                .humanReadableField("current_max_millis", "current_max", new TimeValue(currentMax, TimeUnit.NANOSECONDS))
+                .humanReadableField("current_avg_millis", "current_avg", new TimeValue(currentAvg, TimeUnit.NANOSECONDS))
+                .endObject();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeVLong(cancellationCount);
+            out.writeVLong(currentMax);
+            out.writeVLong(currentAvg);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Stats stats = (Stats) o;
+            return cancellationCount == stats.cancellationCount && currentMax == stats.currentMax && currentAvg == stats.currentAvg;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(cancellationCount, currentMax, currentAvg);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/HeapUsageTracker.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/HeapUsageTracker.java
new file mode 100644
index 0000000000000..56b9f947f6e37
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/HeapUsageTracker.java
@@ -0,0 +1,180 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.util.MovingAverage;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.monitor.jvm.JvmStats;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.DoubleSupplier;
+
+import static org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER;
+
+/**
+ * HeapUsageTracker evaluates if the task has consumed too much heap than allowed.
+ * It also compares the task's heap usage against a historical moving average of previously completed tasks.
+ *
+ * @opensearch.internal
+ */
+public class HeapUsageTracker extends TaskResourceUsageTracker {
+    private static final Logger logger = LogManager.getLogger(HeapUsageTracker.class);
+    private static final long HEAP_SIZE_BYTES = JvmStats.jvmStats().getMem().getHeapMax().getBytes();
+    private final DoubleSupplier heapVarianceSupplier;
+    private final DoubleSupplier heapPercentThresholdSupplier;
+    private final AtomicReference<MovingAverage> movingAverageReference;
+
+    public HeapUsageTracker(
+        DoubleSupplier heapVarianceSupplier,
+        DoubleSupplier heapPercentThresholdSupplier,
+        int heapMovingAverageWindowSize,
+        ClusterSettings clusterSettings,
+        Setting<Integer> windowSizeSetting
+    ) {
+        this.heapVarianceSupplier = heapVarianceSupplier;
+        this.heapPercentThresholdSupplier = heapPercentThresholdSupplier;
+        this.movingAverageReference = new AtomicReference<>(new MovingAverage(heapMovingAverageWindowSize));
+        clusterSettings.addSettingsUpdateConsumer(windowSizeSetting, this::updateWindowSize);
+    }
+
+    @Override
+    public String name() {
+        return HEAP_USAGE_TRACKER.getName();
+    }
+
+    @Override
+    public void update(Task task) {
+        movingAverageReference.get().record(task.getTotalResourceStats().getMemoryInBytes());
+    }
+
+    @Override
+    public Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task) {
+        MovingAverage movingAverage = movingAverageReference.get();
+
+        // There haven't been enough measurements.
+        if (movingAverage.isReady() == false) {
+            return Optional.empty();
+        }
+
+        double currentUsage = task.getTotalResourceStats().getMemoryInBytes();
+        double averageUsage = movingAverage.getAverage();
+        double variance = heapVarianceSupplier.getAsDouble();
+        double allowedUsage = averageUsage * variance;
+        double threshold = heapPercentThresholdSupplier.getAsDouble() * HEAP_SIZE_BYTES;
+
+        if (isHeapTrackingSupported() == false || currentUsage < threshold || currentUsage < allowedUsage) {
+            return Optional.empty();
+        }
+
+        return Optional.of(
+            new TaskCancellation.Reason(
+                "heap usage exceeded [" + new ByteSizeValue((long) currentUsage) + " >= " + new ByteSizeValue((long) allowedUsage) + "]",
+                (int) (currentUsage / averageUsage)  // TODO: fine-tune the cancellation score/weight
+            )
+        );
+    }
+
+    private void updateWindowSize(int heapMovingAverageWindowSize) {
+        this.movingAverageReference.set(new MovingAverage(heapMovingAverageWindowSize));
+    }
+
+    public static boolean isHeapTrackingSupported() {
+        return HEAP_SIZE_BYTES > 0;
+    }
+
+    /**
+     * Returns true if the increase in heap usage is due to search requests.
+     */
+    public static boolean isHeapUsageDominatedBySearch(List<CancellableTask> cancellableTasks, double heapPercentThreshold) {
+        long usage = cancellableTasks.stream().mapToLong(task -> task.getTotalResourceStats().getMemoryInBytes()).sum();
+        long threshold = (long) (heapPercentThreshold * HEAP_SIZE_BYTES);
+        if (isHeapTrackingSupported() && usage < threshold) {
+            logger.debug("heap usage not dominated by search requests [{}/{}]", usage, threshold);
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public TaskResourceUsageTracker.Stats stats(List<? extends Task> activeTasks) {
+        long currentMax = activeTasks.stream().mapToLong(t -> t.getTotalResourceStats().getMemoryInBytes()).max().orElse(0);
+        long currentAvg = (long) activeTasks.stream().mapToLong(t -> t.getTotalResourceStats().getMemoryInBytes()).average().orElse(0);
+        return new Stats(getCancellations(), currentMax, currentAvg, (long) movingAverageReference.get().getAverage());
+    }
+
+    /**
+     * Stats related to HeapUsageTracker.
+     */
+    public static class Stats implements TaskResourceUsageTracker.Stats {
+        private final long cancellationCount;
+        private final long currentMax;
+        private final long currentAvg;
+        private final long rollingAvg;
+
+        public Stats(long cancellationCount, long currentMax, long currentAvg, long rollingAvg) {
+            this.cancellationCount = cancellationCount;
+            this.currentMax = currentMax;
+            this.currentAvg = currentAvg;
+            this.rollingAvg = rollingAvg;
+        }
+
+        public Stats(StreamInput in) throws IOException {
+            this(in.readVLong(), in.readVLong(), in.readVLong(), in.readVLong());
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.startObject()
+                .field("cancellation_count", cancellationCount)
+                .humanReadableField("current_max_bytes", "current_max", new ByteSizeValue(currentMax))
+                .humanReadableField("current_avg_bytes", "current_avg", new ByteSizeValue(currentAvg))
+                .humanReadableField("rolling_avg_bytes", "rolling_avg", new ByteSizeValue(rollingAvg))
+                .endObject();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeVLong(cancellationCount);
+            out.writeVLong(currentMax);
+            out.writeVLong(currentAvg);
+            out.writeVLong(rollingAvg);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Stats stats = (Stats) o;
+            return cancellationCount == stats.cancellationCount
+                && currentMax == stats.currentMax
+                && currentAvg == stats.currentAvg
+                && rollingAvg == stats.rollingAvg;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(cancellationCount, currentMax, currentAvg, rollingAvg);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/NodeDuressTracker.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/NodeDuressTracker.java
new file mode 100644
index 0000000000000..8e35c724a8fef
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/NodeDuressTracker.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.common.util.Streak;
+
+import java.util.function.BooleanSupplier;
+
+/**
+ * NodeDuressTracker is used to check if the node is in duress.
+ *
+ * @opensearch.internal
+ */
+public class NodeDuressTracker {
+    /**
+     * Tracks the number of consecutive breaches.
+     */
+    private final Streak breaches = new Streak();
+
+    /**
+     * Predicate that returns true when the node is in duress.
+     */
+    private final BooleanSupplier isNodeInDuress;
+
+    public NodeDuressTracker(BooleanSupplier isNodeInDuress) {
+        this.isNodeInDuress = isNodeInDuress;
+    }
+
+    /**
+     * Evaluates the predicate and returns the number of consecutive breaches.
+     */
+    public int check() {
+        return breaches.record(isNodeInDuress.getAsBoolean());
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTracker.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTracker.java
new file mode 100644
index 0000000000000..ce15e9e9b6622
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTracker.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * TaskResourceUsageTracker is used to track completions and cancellations of search related tasks.
+ *
+ * @opensearch.internal
+ */
+public abstract class TaskResourceUsageTracker {
+    /**
+     * Counts the number of cancellations made due to this tracker.
+     */
+    private final AtomicLong cancellations = new AtomicLong();
+
+    public long incrementCancellations() {
+        return cancellations.incrementAndGet();
+    }
+
+    public long getCancellations() {
+        return cancellations.get();
+    }
+
+    /**
+     * Returns a unique name for this tracker.
+     */
+    public abstract String name();
+
+    /**
+     * Notifies the tracker to update its state when a task execution completes.
+     */
+    public void update(Task task) {}
+
+    /**
+     * Returns the cancellation reason for the given task, if it's eligible for cancellation.
+     */
+    public abstract Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task);
+
+    /**
+     * Returns the tracker's state for tasks as seen in the stats API.
+     */
+    public abstract Stats stats(List<? extends Task> activeTasks);
+
+    /**
+     * Represents the tracker's state as seen in the stats API.
+     */
+    public interface Stats extends ToXContentObject, Writeable {}
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTrackerType.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTrackerType.java
new file mode 100644
index 0000000000000..2211d28ad30c0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/TaskResourceUsageTrackerType.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+/**
+ * Defines the type of TaskResourceUsageTracker.
+ */
+public enum TaskResourceUsageTrackerType {
+    CPU_USAGE_TRACKER("cpu_usage_tracker"),
+    HEAP_USAGE_TRACKER("heap_usage_tracker"),
+    ELAPSED_TIME_TRACKER("elapsed_time_tracker");
+
+    private final String name;
+
+    TaskResourceUsageTrackerType(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public static TaskResourceUsageTrackerType fromName(String name) {
+        switch (name) {
+            case "cpu_usage_tracker":
+                return CPU_USAGE_TRACKER;
+            case "heap_usage_tracker":
+                return HEAP_USAGE_TRACKER;
+            case "elapsed_time_tracker":
+                return ELAPSED_TIME_TRACKER;
+        }
+
+        throw new IllegalArgumentException("Invalid TaskResourceUsageTrackerType: " + name);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/backpressure/trackers/package-info.java b/server/src/main/java/org/opensearch/search/backpressure/trackers/package-info.java
new file mode 100644
index 0000000000000..da0532421391e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/backpressure/trackers/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains trackers to check if resource usage limits are breached on a node or task level.
+ */
+package org.opensearch.search.backpressure.trackers;
diff --git a/server/src/main/java/org/opensearch/search/builder/PointInTimeBuilder.java b/server/src/main/java/org/opensearch/search/builder/PointInTimeBuilder.java
index 3cfd673d28c84..c50f3c75213dd 100644
--- a/server/src/main/java/org/opensearch/search/builder/PointInTimeBuilder.java
+++ b/server/src/main/java/org/opensearch/search/builder/PointInTimeBuilder.java
@@ -33,15 +33,15 @@
 package org.opensearch.search.builder;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +49,8 @@
 /**
  * A search request with a point in time will execute using the reader contexts associated with that point time
  * instead of the latest reader contexts.
+ *
+ * @opensearch.internal
  */
 public final class PointInTimeBuilder implements Writeable, ToXContentObject {
     private static final ParseField ID_FIELD = new ParseField("id");
diff --git a/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilder.java b/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilder.java
index 8c162e1fa4a33..51e596500a181 100644
--- a/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilder.java
@@ -34,22 +34,23 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.Rewriteable;
@@ -77,6 +78,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
@@ -89,6 +91,8 @@
  * {@link org.opensearch.search.builder.SearchSourceBuilder#searchSource()}.
  *
  * @see org.opensearch.action.search.SearchRequest#source(SearchSourceBuilder)
+ *
+ * @opensearch.internal
  */
 public final class SearchSourceBuilder implements Writeable, ToXContentObject, Rewriteable<SearchSourceBuilder> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(SearchSourceBuilder.class);
@@ -126,6 +130,7 @@ public final class SearchSourceBuilder implements Writeable, ToXContentObject, R
     public static final ParseField COLLAPSE = new ParseField("collapse");
     public static final ParseField SLICE = new ParseField("slice");
     public static final ParseField POINT_IN_TIME = new ParseField("pit");
+    public static final ParseField SEARCH_PIPELINE = new ParseField("search_pipeline");
 
     public static SearchSourceBuilder fromXContent(XContentParser parser) throws IOException {
         return fromXContent(parser, true);
@@ -206,6 +211,8 @@ public static HighlightBuilder highlight() {
 
     private PointInTimeBuilder pointInTimeBuilder = null;
 
+    private Map<String, Object> searchPipelineSource = null;
+
     /**
      * Constructs a new search source builder.
      */
@@ -271,6 +278,11 @@ public SearchSourceBuilder(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             pointInTimeBuilder = in.readOptionalWriteable(PointInTimeBuilder::new);
         }
+        if (in.getVersion().onOrAfter(Version.V_2_8_0)) {
+            if (in.readBoolean()) {
+                searchPipelineSource = in.readMap();
+            }
+        }
     }
 
     @Override
@@ -338,6 +350,12 @@ public void writeTo(StreamOutput out) throws IOException {
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             out.writeOptionalWriteable(pointInTimeBuilder);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_8_0)) {
+            out.writeBoolean(searchPipelineSource != null);
+            if (searchPipelineSource != null) {
+                out.writeMap(searchPipelineSource);
+            }
+        }
     }
 
     /**
@@ -996,6 +1014,21 @@ public SearchSourceBuilder pointInTimeBuilder(PointInTimeBuilder builder) {
         return this;
     }
 
+    /**
+     * @return a search pipeline defined within the search source (see {@link org.opensearch.search.pipeline.SearchPipelineService})
+     */
+    public Map<String, Object> searchPipelineSource() {
+        return searchPipelineSource;
+    }
+
+    /**
+     * Define a search pipeline to process this search request and/or its response. See {@link org.opensearch.search.pipeline.SearchPipelineService}.
+     */
+    public SearchSourceBuilder searchPipelineSource(Map<String, Object> searchPipelineSource) {
+        this.searchPipelineSource = searchPipelineSource;
+        return this;
+    }
+
     /**
      * Rewrites this search source builder into its primitive form. e.g. by
      * rewriting the QueryBuilder. If the builder did not change the identity
@@ -1233,6 +1266,8 @@ public void parseXContent(XContentParser parser, boolean checkTrailingTokens) th
                         collapse = CollapseBuilder.fromXContent(parser);
                     } else if (POINT_IN_TIME.match(currentFieldName, parser.getDeprecationHandler())) {
                         pointInTimeBuilder = PointInTimeBuilder.fromXContent(parser);
+                    } else if (SEARCH_PIPELINE.match(currentFieldName, parser.getDeprecationHandler())) {
+                        searchPipelineSource = parser.mapOrdered();
                     } else {
                         throw new ParsingException(
                             parser.getTokenLocation(),
@@ -1458,6 +1493,9 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
         if (pointInTimeBuilder != null) {
             pointInTimeBuilder.toXContent(builder, params);
         }
+        if (searchPipelineSource != null) {
+            builder.field(SEARCH_PIPELINE.getPreferredName(), searchPipelineSource);
+        }
         return builder;
     }
 
@@ -1469,6 +1507,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Boosts on an index
+     *
+     * @opensearch.internal
+     */
     public static class IndexBoost implements Writeable, ToXContentObject {
         private final String index;
         private final float boost;
@@ -1565,6 +1608,11 @@ public boolean equals(Object obj) {
 
     }
 
+    /**
+     * Script field
+     *
+     * @opensearch.internal
+     */
     public static class ScriptField implements Writeable, ToXContentFragment {
 
         private final boolean ignoreFailure;
@@ -1772,7 +1820,7 @@ public String toString() {
 
     public String toString(Params params) {
         try {
-            return XContentHelper.toXContent(this, XContentType.JSON, params, true).utf8ToString();
+            return XContentHelper.toXContent(this, MediaTypeRegistry.JSON, params, true).utf8ToString();
         } catch (IOException e) {
             throw new OpenSearchException(e);
         }
diff --git a/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilderException.java b/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilderException.java
index 700950cdf894c..83e5cf2c86958 100644
--- a/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilderException.java
+++ b/server/src/main/java/org/opensearch/search/builder/SearchSourceBuilderException.java
@@ -33,10 +33,15 @@
 package org.opensearch.search.builder;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Error thrown on source builders during search phase
+ *
+ * @opensearch.internal
+ */
 public class SearchSourceBuilderException extends OpenSearchException {
 
     public SearchSourceBuilderException(String msg) {
diff --git a/server/src/main/java/org/opensearch/search/builder/package-info.java b/server/src/main/java/org/opensearch/search/builder/package-info.java
new file mode 100644
index 0000000000000..7de5bce1f7c14
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/builder/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Search builders package. */
+package org.opensearch.search.builder;
diff --git a/server/src/main/java/org/opensearch/search/collapse/CollapseBuilder.java b/server/src/main/java/org/opensearch/search/collapse/CollapseBuilder.java
index e4064eed55f30..73802cbd7a849 100644
--- a/server/src/main/java/org/opensearch/search/collapse/CollapseBuilder.java
+++ b/server/src/main/java/org/opensearch/search/collapse/CollapseBuilder.java
@@ -31,17 +31,17 @@
 
 package org.opensearch.search.collapse;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
@@ -56,6 +56,8 @@
 
 /**
  * A builder that enables field collapsing on search request.
+ *
+ * @opensearch.internal
  */
 public class CollapseBuilder implements Writeable, ToXContentObject {
     public static final ParseField FIELD_FIELD = new ParseField("field");
diff --git a/server/src/main/java/org/opensearch/search/collapse/CollapseContext.java b/server/src/main/java/org/opensearch/search/collapse/CollapseContext.java
index 75f340de4dd16..09a612a15d762 100644
--- a/server/src/main/java/org/opensearch/search/collapse/CollapseContext.java
+++ b/server/src/main/java/org/opensearch/search/collapse/CollapseContext.java
@@ -42,6 +42,8 @@
 
 /**
  * Context used for field collapsing
+ *
+ * @opensearch.internal
  */
 public class CollapseContext {
     private final String fieldName;
diff --git a/server/src/main/java/org/opensearch/search/collapse/package-info.java b/server/src/main/java/org/opensearch/search/collapse/package-info.java
new file mode 100644
index 0000000000000..2a3c6e3a4f507
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/collapse/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Collapse package. */
+package org.opensearch.search.collapse;
diff --git a/server/src/main/java/org/opensearch/search/dfs/AggregatedDfs.java b/server/src/main/java/org/opensearch/search/dfs/AggregatedDfs.java
index 0c1cba2c84cf0..35ab0c0701b4e 100644
--- a/server/src/main/java/org/opensearch/search/dfs/AggregatedDfs.java
+++ b/server/src/main/java/org/opensearch/search/dfs/AggregatedDfs.java
@@ -32,39 +32,45 @@
 
 package org.opensearch.search.dfs;
 
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.CollectionStatistics;
 import org.apache.lucene.search.TermStatistics;
-import org.opensearch.common.collect.HppcMaps;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
+/**
+ * Compute global distributed frequency across the index
+ *
+ * @opensearch.internal
+ */
 public class AggregatedDfs implements Writeable {
 
-    private ObjectObjectHashMap<Term, TermStatistics> termStatistics;
-    private ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics;
+    private Map<Term, TermStatistics> termStatistics;
+    private Map<String, CollectionStatistics> fieldStatistics;
     private long maxDoc;
 
     public AggregatedDfs(StreamInput in) throws IOException {
         int size = in.readVInt();
-        termStatistics = HppcMaps.newMap(size);
+        final Map<Term, TermStatistics> termStatistics = new HashMap<>(size);
         for (int i = 0; i < size; i++) {
             Term term = new Term(in.readString(), in.readBytesRef());
             TermStatistics stats = new TermStatistics(in.readBytesRef(), in.readVLong(), DfsSearchResult.subOne(in.readVLong()));
             termStatistics.put(term, stats);
         }
-        fieldStatistics = DfsSearchResult.readFieldStats(in);
+        this.termStatistics = Collections.unmodifiableMap(termStatistics);
+        this.fieldStatistics = DfsSearchResult.readFieldStats(in);
         maxDoc = in.readVLong();
     }
 
     public AggregatedDfs(
-        ObjectObjectHashMap<Term, TermStatistics> termStatistics,
-        ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics,
+        final Map<Term, TermStatistics> termStatistics,
+        final Map<String, CollectionStatistics> fieldStatistics,
         long maxDoc
     ) {
         this.termStatistics = termStatistics;
@@ -72,11 +78,11 @@ public AggregatedDfs(
         this.maxDoc = maxDoc;
     }
 
-    public ObjectObjectHashMap<Term, TermStatistics> termStatistics() {
+    public Map<Term, TermStatistics> termStatistics() {
         return termStatistics;
     }
 
-    public ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics() {
+    public Map<String, CollectionStatistics> fieldStatistics() {
         return fieldStatistics;
     }
 
@@ -88,11 +94,11 @@ public long maxDoc() {
     public void writeTo(final StreamOutput out) throws IOException {
         out.writeVInt(termStatistics.size());
 
-        for (ObjectObjectCursor<Term, TermStatistics> c : termStatistics()) {
-            Term term = c.key;
+        for (final Map.Entry<Term, TermStatistics> c : termStatistics().entrySet()) {
+            Term term = c.getKey();
             out.writeString(term.field());
             out.writeBytesRef(term.bytes());
-            TermStatistics stats = c.value;
+            TermStatistics stats = c.getValue();
             out.writeBytesRef(stats.term());
             out.writeVLong(stats.docFreq());
             out.writeVLong(DfsSearchResult.addOne(stats.totalTermFreq()));
diff --git a/server/src/main/java/org/opensearch/search/dfs/DfsPhase.java b/server/src/main/java/org/opensearch/search/dfs/DfsPhase.java
index 72ccc1fd5aca8..b5f6c082a18c5 100644
--- a/server/src/main/java/org/opensearch/search/dfs/DfsPhase.java
+++ b/server/src/main/java/org/opensearch/search/dfs/DfsPhase.java
@@ -32,17 +32,15 @@
 
 package org.opensearch.search.dfs;
 
-import com.carrotsearch.hppc.ObjectObjectHashMap;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.CollectionStatistics;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.TermStatistics;
-import org.opensearch.common.collect.HppcMaps;
+import org.opensearch.core.tasks.TaskCancelledException;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.rescore.RescoreContext;
-import org.opensearch.tasks.TaskCancelledException;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -51,12 +49,14 @@
 /**
  * Dfs phase of a search request, used to make scoring 100% accurate by collecting additional info from each shard before the query phase.
  * The additional information is used to better compare the scores coming from all the shards, which depend on local factors (e.g. idf)
+ *
+ * @opensearch.internal
  */
 public class DfsPhase {
 
     public void execute(SearchContext context) {
         try {
-            ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics = HppcMaps.newNoNullKeysMap();
+            Map<String, CollectionStatistics> fieldStatistics = new HashMap<>();
             Map<Term, TermStatistics> stats = new HashMap<>();
             IndexSearcher searcher = new IndexSearcher(context.searcher().getIndexReader()) {
                 @Override
diff --git a/server/src/main/java/org/opensearch/search/dfs/DfsPhaseExecutionException.java b/server/src/main/java/org/opensearch/search/dfs/DfsPhaseExecutionException.java
index 9344672c16807..f875304cae4fd 100644
--- a/server/src/main/java/org/opensearch/search/dfs/DfsPhaseExecutionException.java
+++ b/server/src/main/java/org/opensearch/search/dfs/DfsPhaseExecutionException.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.dfs;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Thrown if there are any errors in the DFS phase
+ *
+ * @opensearch.internal
+ */
 public class DfsPhaseExecutionException extends SearchException {
 
     public DfsPhaseExecutionException(SearchShardTarget shardTarget, String msg, Throwable t) {
diff --git a/server/src/main/java/org/opensearch/search/dfs/DfsSearchResult.java b/server/src/main/java/org/opensearch/search/dfs/DfsSearchResult.java
index 48ab8aa683133..09e8af8833975 100644
--- a/server/src/main/java/org/opensearch/search/dfs/DfsSearchResult.java
+++ b/server/src/main/java/org/opensearch/search/dfs/DfsSearchResult.java
@@ -32,30 +32,35 @@
 
 package org.opensearch.search.dfs;
 
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.CollectionStatistics;
 import org.apache.lucene.search.TermStatistics;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.collect.HppcMaps;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
+/**
+ * Result from a Distributed Frequency Search phase
+ *
+ * @opensearch.internal
+ */
 public class DfsSearchResult extends SearchPhaseResult {
 
     private static final Term[] EMPTY_TERMS = new Term[0];
     private static final TermStatistics[] EMPTY_TERM_STATS = new TermStatistics[0];
     private Term[] terms;
     private TermStatistics[] termStatistics;
-    private ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics = HppcMaps.newNoNullKeysMap();
+    private Map<String, CollectionStatistics> fieldStatistics;
     private int maxDoc;
 
     public DfsSearchResult(StreamInput in) throws IOException {
@@ -71,7 +76,7 @@ public DfsSearchResult(StreamInput in) throws IOException {
             }
         }
         this.termStatistics = readTermStats(in, terms);
-        fieldStatistics = readFieldStats(in);
+        this.fieldStatistics = readFieldStats(in);
 
         maxDoc = in.readVInt();
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
@@ -100,8 +105,8 @@ public DfsSearchResult termsStatistics(Term[] terms, TermStatistics[] termStatis
         return this;
     }
 
-    public DfsSearchResult fieldStatistics(ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics) {
-        this.fieldStatistics = fieldStatistics;
+    public DfsSearchResult fieldStatistics(final Map<String, CollectionStatistics> fieldStatistics) {
+        this.fieldStatistics = Collections.unmodifiableMap(fieldStatistics);
         return this;
     }
 
@@ -113,7 +118,7 @@ public TermStatistics[] termStatistics() {
         return termStatistics;
     }
 
-    public ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics() {
+    public Map<String, CollectionStatistics> fieldStatistics() {
         return fieldStatistics;
     }
 
@@ -133,13 +138,12 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
-    public static void writeFieldStats(StreamOutput out, ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics)
-        throws IOException {
+    public static void writeFieldStats(StreamOutput out, final Map<String, CollectionStatistics> fieldStatistics) throws IOException {
         out.writeVInt(fieldStatistics.size());
 
-        for (ObjectObjectCursor<String, CollectionStatistics> c : fieldStatistics) {
-            out.writeString(c.key);
-            CollectionStatistics statistics = c.value;
+        for (final Map.Entry<String, CollectionStatistics> c : fieldStatistics.entrySet()) {
+            out.writeString(c.getKey());
+            CollectionStatistics statistics = c.getValue();
             assert statistics.maxDoc() >= 0;
             out.writeVLong(statistics.maxDoc());
             if (out.getVersion().onOrAfter(LegacyESVersion.V_7_0_0)) {
@@ -173,9 +177,9 @@ public static void writeSingleTermStats(StreamOutput out, TermStatistics termSta
         }
     }
 
-    static ObjectObjectHashMap<String, CollectionStatistics> readFieldStats(StreamInput in) throws IOException {
+    static Map<String, CollectionStatistics> readFieldStats(StreamInput in) throws IOException {
         final int numFieldStatistics = in.readVInt();
-        ObjectObjectHashMap<String, CollectionStatistics> fieldStatistics = HppcMaps.newNoNullKeysMap(numFieldStatistics);
+        final Map<String, CollectionStatistics> fieldStatistics = new HashMap<>(numFieldStatistics);
         for (int i = 0; i < numFieldStatistics; i++) {
             final String field = in.readString();
             assert field != null;
@@ -196,7 +200,7 @@ static ObjectObjectHashMap<String, CollectionStatistics> readFieldStats(StreamIn
             CollectionStatistics stats = new CollectionStatistics(field, maxDoc, docCount, sumTotalTermFreq, sumDocFreq);
             fieldStatistics.put(field, stats);
         }
-        return fieldStatistics;
+        return Collections.unmodifiableMap(fieldStatistics);
     }
 
     static TermStatistics[] readTermStats(StreamInput in, Term[] terms) throws IOException {
diff --git a/server/src/main/java/org/opensearch/search/dfs/package-info.java b/server/src/main/java/org/opensearch/search/dfs/package-info.java
new file mode 100644
index 0000000000000..1469d4d0e9dc4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/dfs/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base DFS search package. */
+package org.opensearch.search.dfs;
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchContext.java b/server/src/main/java/org/opensearch/search/fetch/FetchContext.java
index d26dbac33afea..7e36ace9e2112 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchContext.java
@@ -57,6 +57,8 @@
 
 /**
  * Encapsulates state required to execute fetch phases
+ *
+ * @opensearch.internal
  */
 public class FetchContext {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchPhase.java b/server/src/main/java/org/opensearch/search/fetch/FetchPhase.java
index e50f903b22920..09c407cfc70be 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchPhase.java
@@ -48,10 +48,12 @@
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.lucene.index.SequentialStoredFieldsLeafReader;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.fieldvisitor.CustomFieldsVisitor;
 import org.opensearch.index.fieldvisitor.FieldsVisitor;
@@ -71,7 +73,6 @@
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.search.lookup.SourceLookup;
-import org.opensearch.tasks.TaskCancelledException;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -90,6 +91,8 @@
 /**
  * Fetch phase of a search request, used to fetch the actual top matching documents to be returned to the client, identified
  * after reducing all of the matches returned by the query phase
+ *
+ * @opensearch.internal
  */
 public class FetchPhase {
     private static final Logger LOGGER = LogManager.getLogger(FetchPhase.class);
@@ -155,9 +158,9 @@ public void execute(SearchContext context) {
                         // So we do a little hack here and pretend we're going to do merges in order to
                         // get better sequential access.
                         SequentialStoredFieldsLeafReader lf = (SequentialStoredFieldsLeafReader) currentReaderContext.reader();
-                        fieldReader = lf.getSequentialStoredFieldsReader()::visitDocument;
+                        fieldReader = lf.getSequentialStoredFieldsReader()::document;
                     } else {
-                        fieldReader = currentReaderContext.reader()::document;
+                        fieldReader = currentReaderContext.reader().storedFields()::document;
                     }
                     for (FetchSubPhaseProcessor processor : processors) {
                         processor.setNextReader(currentReaderContext);
@@ -375,7 +378,7 @@ private HitContext prepareNestedHitContext(
 
         String rootId;
         Map<String, Object> rootSourceAsMap = null;
-        XContentType rootSourceContentType = null;
+        MediaType rootSourceContentType = null;
 
         int nestedDocId = nestedTopDocId - subReaderContext.docBase;
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchPhaseExecutionException.java b/server/src/main/java/org/opensearch/search/fetch/FetchPhaseExecutionException.java
index 4b9310edfef9a..ff52a57ffe7bb 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchPhaseExecutionException.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchPhaseExecutionException.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.fetch;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Thrown when there are errors during the fetch phase
+ *
+ * @opensearch.internal
+ */
 public class FetchPhaseExecutionException extends SearchException {
 
     public FetchPhaseExecutionException(SearchShardTarget shardTarget, String msg, Throwable t) {
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchSearchResult.java b/server/src/main/java/org/opensearch/search/fetch/FetchSearchResult.java
index f4d4849a5a406..a8560863d8d98 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchSearchResult.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchSearchResult.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.fetch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.SearchPhaseResult;
@@ -43,6 +43,11 @@
 
 import java.io.IOException;
 
+/**
+ * Result from a fetch
+ *
+ * @opensearch.internal
+ */
 public final class FetchSearchResult extends SearchPhaseResult {
 
     private SearchHits hits;
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchSubPhase.java b/server/src/main/java/org/opensearch/search/fetch/FetchSubPhase.java
index 3c38249d88648..fa30b2a5c7450 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchSubPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchSubPhase.java
@@ -42,9 +42,16 @@
 
 /**
  * Sub phase within the fetch phase used to fetch things *about* the documents like highlighting or matched queries.
+ *
+ * @opensearch.internal
  */
 public interface FetchSubPhase {
 
+    /**
+     * The hit context for the fetch subphase
+     *
+     * @opensearch.internal
+     */
     class HitContext {
         private final SearchHit hit;
         private final LeafReaderContext readerContext;
diff --git a/server/src/main/java/org/opensearch/search/fetch/FetchSubPhaseProcessor.java b/server/src/main/java/org/opensearch/search/fetch/FetchSubPhaseProcessor.java
index ce32cf62bec93..6288861fff695 100644
--- a/server/src/main/java/org/opensearch/search/fetch/FetchSubPhaseProcessor.java
+++ b/server/src/main/java/org/opensearch/search/fetch/FetchSubPhaseProcessor.java
@@ -39,6 +39,8 @@
 
 /**
  * Executes the logic for a {@link FetchSubPhase} against a particular leaf reader and hit
+ *
+ * @opensearch.internal
  */
 public interface FetchSubPhaseProcessor {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/QueryFetchSearchResult.java b/server/src/main/java/org/opensearch/search/fetch/QueryFetchSearchResult.java
index 5d655ce8a4f8f..ce4c59fc77489 100644
--- a/server/src/main/java/org/opensearch/search/fetch/QueryFetchSearchResult.java
+++ b/server/src/main/java/org/opensearch/search/fetch/QueryFetchSearchResult.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.fetch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.ShardSearchContextId;
@@ -41,6 +41,11 @@
 
 import java.io.IOException;
 
+/**
+ * Query fetch result
+ *
+ * @opensearch.internal
+ */
 public final class QueryFetchSearchResult extends SearchPhaseResult {
 
     private final QuerySearchResult queryResult;
diff --git a/server/src/main/java/org/opensearch/search/fetch/ScrollQueryFetchSearchResult.java b/server/src/main/java/org/opensearch/search/fetch/ScrollQueryFetchSearchResult.java
index 3156ccc11bc12..415350b4c5dc7 100644
--- a/server/src/main/java/org/opensearch/search/fetch/ScrollQueryFetchSearchResult.java
+++ b/server/src/main/java/org/opensearch/search/fetch/ScrollQueryFetchSearchResult.java
@@ -32,14 +32,19 @@
 
 package org.opensearch.search.fetch;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
 
+/**
+ * Scroll fetch result
+ *
+ * @opensearch.internal
+ */
 public final class ScrollQueryFetchSearchResult extends SearchPhaseResult {
 
     private final QueryFetchSearchResult result;
diff --git a/server/src/main/java/org/opensearch/search/fetch/ShardFetchRequest.java b/server/src/main/java/org/opensearch/search/fetch/ShardFetchRequest.java
index 65f595938a563..8e6b2a3eef527 100644
--- a/server/src/main/java/org/opensearch/search/fetch/ShardFetchRequest.java
+++ b/server/src/main/java/org/opensearch/search/fetch/ShardFetchRequest.java
@@ -32,28 +32,30 @@
 
 package org.opensearch.search.fetch;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.ScoreDoc;
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.RescoreDocIds;
 import org.opensearch.search.dfs.AggregatedDfs;
-import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
+import java.util.Collection;
 import java.util.Map;
 
 /**
  * Shard level fetch base request. Holds all the info needed to execute a fetch.
  * Used with search scroll as the original request doesn't hold indices.
+ *
+ * @opensearch.internal
  */
 public class ShardFetchRequest extends TransportRequest {
 
@@ -65,9 +67,9 @@ public class ShardFetchRequest extends TransportRequest {
 
     private ScoreDoc lastEmittedDoc;
 
-    public ShardFetchRequest(ShardSearchContextId contextId, IntArrayList list, ScoreDoc lastEmittedDoc) {
+    public ShardFetchRequest(ShardSearchContextId contextId, Collection<Integer> list, ScoreDoc lastEmittedDoc) {
         this.contextId = contextId;
-        this.docIds = list.buffer;
+        this.docIds = list.stream().mapToInt(Integer::intValue).toArray();
         this.size = list.size();
         this.lastEmittedDoc = lastEmittedDoc;
     }
diff --git a/server/src/main/java/org/opensearch/search/fetch/ShardFetchSearchRequest.java b/server/src/main/java/org/opensearch/search/fetch/ShardFetchSearchRequest.java
index aadb13c1543e1..0172bfd03ffc8 100644
--- a/server/src/main/java/org/opensearch/search/fetch/ShardFetchSearchRequest.java
+++ b/server/src/main/java/org/opensearch/search/fetch/ShardFetchSearchRequest.java
@@ -32,24 +32,26 @@
 
 package org.opensearch.search.fetch;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.apache.lucene.search.ScoreDoc;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.RescoreDocIds;
 import org.opensearch.search.dfs.AggregatedDfs;
+import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 
 import java.io.IOException;
+import java.util.List;
 
 /**
  * Shard level fetch request used with search. Holds indices taken from the original search request
  * and implements {@link org.opensearch.action.IndicesRequest}.
+ *
+ * @opensearch.internal
  */
 public class ShardFetchSearchRequest extends ShardFetchRequest implements IndicesRequest {
 
@@ -62,7 +64,7 @@ public ShardFetchSearchRequest(
         OriginalIndices originalIndices,
         ShardSearchContextId id,
         ShardSearchRequest shardSearchRequest,
-        IntArrayList list,
+        List<Integer> list,
         ScoreDoc lastEmittedDoc,
         RescoreDocIds rescoreDocIds,
         AggregatedDfs aggregatedDfs
diff --git a/server/src/main/java/org/opensearch/search/fetch/StoredFieldsContext.java b/server/src/main/java/org/opensearch/search/fetch/StoredFieldsContext.java
index 225cfad2b611c..8cf70b41009a3 100644
--- a/server/src/main/java/org/opensearch/search/fetch/StoredFieldsContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/StoredFieldsContext.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.fetch;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.RestRequest;
 
 import java.io.IOException;
@@ -50,6 +50,8 @@
 
 /**
  * Context used to fetch the {@code stored_fields}.
+ *
+ * @opensearch.internal
  */
 public class StoredFieldsContext implements Writeable {
     public static final String _NONE_ = "_none_";
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/ExplainPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/ExplainPhase.java
index 42b2d6e94de19..d34cc9bf49421 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/ExplainPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/ExplainPhase.java
@@ -42,6 +42,8 @@
 
 /**
  * Explains the scoring calculations for the top hits.
+ *
+ * @opensearch.internal
  */
 public final class ExplainPhase implements FetchSubPhase {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesContext.java
index 3bfb3365fe46e..ce5bd152cca00 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesContext.java
@@ -41,6 +41,8 @@
 
 /**
  * All the required context to pull a field from the doc values.
+ *
+ * @opensearch.internal
  */
 public class FetchDocValuesContext {
     private final List<FieldAndFormat> fields;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesPhase.java
index b44d856008407..a8ab8c0dcb8a8 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchDocValuesPhase.java
@@ -49,6 +49,8 @@
  * Fetch sub phase which pulls data from doc values.
  *
  * Specifying {@code "docvalue_fields": ["field1", "field2"]}
+ *
+ * @opensearch.internal
  */
 public final class FetchDocValuesPhase implements FetchSubPhase {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsContext.java
index 5c481ccfef2d6..3803dedae9b57 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsContext.java
@@ -35,6 +35,8 @@
 
 /**
  * The context needed to retrieve fields.
+ *
+ * @opensearch.internal
  */
 public class FetchFieldsContext {
     private final List<FieldAndFormat> fields;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsPhase.java
index 353ec3f8080d2..9988abb778bce 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchFieldsPhase.java
@@ -50,6 +50,8 @@
 /**
  * A fetch sub-phase for high-level field retrieval. Given a list of fields, it
  * retrieves the field values from _source and returns them as document fields.
+ *
+ * @opensearch.internal
  */
 public final class FetchFieldsPhase implements FetchSubPhase {
 
@@ -94,7 +96,7 @@ public void process(HitContext hitContext) throws IOException {
     private Set<String> getIgnoredFields(SearchHit hit) {
         DocumentField field = hit.field(IgnoredFieldMapper.NAME);
         if (field == null) {
-            return org.opensearch.common.collect.Set.of();
+            return Set.of();
         }
 
         Set<String> ignoredFields = new HashSet<>();
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchScorePhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchScorePhase.java
index a83c994d91c2a..3516df482d321 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchScorePhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchScorePhase.java
@@ -44,6 +44,11 @@
 
 import java.io.IOException;
 
+/**
+ * Fetches the score of a query match during search phase
+ *
+ * @opensearch.internal
+ */
 public class FetchScorePhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourceContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourceContext.java
index d8b803447c25f..37a386ad5cbd5 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourceContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourceContext.java
@@ -33,16 +33,16 @@
 package org.opensearch.search.fetch.subphase;
 
 import org.opensearch.common.Booleans;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.RestRequest;
 
 import java.io.IOException;
@@ -54,6 +54,8 @@
 
 /**
  * Context used to fetch the {@code _source}.
+ *
+ * @opensearch.internal
  */
 public class FetchSourceContext implements Writeable, ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourcePhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourcePhase.java
index 30274ac697a4d..3ea5756ea46b4 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourcePhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchSourcePhase.java
@@ -34,9 +34,9 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.fetch.FetchContext;
 import org.opensearch.search.fetch.FetchSubPhase;
@@ -46,6 +46,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Fetches the document source during search phase
+ *
+ * @opensearch.internal
+ */
 public final class FetchSourcePhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchVersionPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchVersionPhase.java
index d2d4740a32cd6..06d37531385a1 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FetchVersionPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FetchVersionPhase.java
@@ -41,6 +41,11 @@
 
 import java.io.IOException;
 
+/**
+ * Fetches the version of a term during search phase
+ *
+ * @opensearch.internal
+ */
 public final class FetchVersionPhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FieldAndFormat.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FieldAndFormat.java
index c87151170e17e..f7e4b06624c76 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FieldAndFormat.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FieldAndFormat.java
@@ -33,15 +33,15 @@
 package org.opensearch.search.fetch.subphase;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -49,6 +49,8 @@
 /**
  * Wrapper around a field name and the format that should be used to
  * display values of this field.
+ *
+ * @opensearch.internal
  */
 public final class FieldAndFormat implements Writeable, ToXContentObject {
     private static final ParseField FIELD_FIELD = new ParseField("field");
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/FieldFetcher.java b/server/src/main/java/org/opensearch/search/fetch/subphase/FieldFetcher.java
index 6790a1a79d634..e2402c03c0bd6 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/FieldFetcher.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/FieldFetcher.java
@@ -51,6 +51,8 @@
 /**
  * A helper class to {@link FetchFieldsPhase} that's initialized with a list of field patterns to fetch.
  * Then given a specific document, it can retrieve the corresponding fields from the document's source.
+ *
+ * @opensearch.internal
  */
 public class FieldFetcher {
     public static FieldFetcher create(QueryShardContext context, SearchLookup searchLookup, Collection<FieldAndFormat> fieldAndFormats) {
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsContext.java
index 22acd599d18c6..f50524244b115 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsContext.java
@@ -58,6 +58,8 @@
 
 /**
  * Context used for inner hits retrieval
+ *
+ * @opensearch.internal
  */
 public final class InnerHitsContext {
     private final Map<String, InnerHitSubContext> innerHits;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsPhase.java
index 56020d334a446..0b07dc35f13bb 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/InnerHitsPhase.java
@@ -49,6 +49,11 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Gets the inner hits of a document during search
+ *
+ * @opensearch.internal
+ */
 public final class InnerHitsPhase implements FetchSubPhase {
 
     private final FetchPhase fetchPhase;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/MatchedQueriesPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/MatchedQueriesPhase.java
index 9d69d54488734..6c589438d6b4c 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/MatchedQueriesPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/MatchedQueriesPhase.java
@@ -48,6 +48,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Fetches queries that match the document during search phase
+ *
+ * @opensearch.internal
+ */
 public final class MatchedQueriesPhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsContext.java
index e3a6c6951c405..78c35098d9cc4 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsContext.java
@@ -37,8 +37,18 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Context used for script fields
+ *
+ * @opensearch.internal
+ */
 public class ScriptFieldsContext {
 
+    /**
+     * Script field use in the script fields context
+     *
+     * @opensearch.internal
+     */
     public static class ScriptField {
         private final String name;
         private final FieldScript.LeafFactory script;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsPhase.java
index d2425abbc0997..67d1863050a7b 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/ScriptFieldsPhase.java
@@ -33,7 +33,7 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.script.FieldScript;
 import org.opensearch.search.fetch.FetchContext;
 import org.opensearch.search.fetch.FetchSubPhase;
@@ -45,6 +45,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Gets the scripted fields during search phase
+ *
+ * @opensearch.internal
+ */
 public final class ScriptFieldsPhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/SeqNoPrimaryTermPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/SeqNoPrimaryTermPhase.java
index fa02031991928..b3926cfd70e4d 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/SeqNoPrimaryTermPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/SeqNoPrimaryTermPhase.java
@@ -41,6 +41,11 @@
 
 import java.io.IOException;
 
+/**
+ * Fetches the sequence number of the primary term during search phase
+ *
+ * @opensearch.internal
+ */
 public final class SeqNoPrimaryTermPhase implements FetchSubPhase {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java
index acf065bc9c0f3..bee75dcecd528 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/AbstractHighlighterBuilder.java
@@ -34,16 +34,18 @@
 
 import org.apache.lucene.search.highlight.SimpleFragmenter;
 import org.apache.lucene.search.highlight.SimpleSpanFragmenter;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.Version;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.Rewriteable;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder.BoundaryScannerType;
@@ -56,12 +58,14 @@
 import java.util.Objects;
 import java.util.function.BiFunction;
 
-import static org.opensearch.common.xcontent.ObjectParser.fromList;
+import static org.opensearch.core.xcontent.ObjectParser.fromList;
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
 /**
  * This abstract class holds parameters shared by {@link HighlightBuilder} and {@link HighlightBuilder.Field}
  * and provides the common setters, equality, hashCode calculation and common serialization
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractHighlighterBuilder<HB extends AbstractHighlighterBuilder<?>>
     implements
@@ -90,6 +94,7 @@ public abstract class AbstractHighlighterBuilder<HB extends AbstractHighlighterB
     public static final ParseField OPTIONS_FIELD = new ParseField("options");
     public static final ParseField HIGHLIGHT_QUERY_FIELD = new ParseField("highlight_query");
     public static final ParseField MATCHED_FIELDS_FIELD = new ParseField("matched_fields");
+    public static final ParseField MAX_ANALYZER_OFFSET_FIELD = new ParseField("max_analyzer_offset");
 
     protected String[] preTags;
 
@@ -127,6 +132,8 @@ public abstract class AbstractHighlighterBuilder<HB extends AbstractHighlighterB
 
     protected Boolean requireFieldMatch;
 
+    protected Integer maxAnalyzerOffset = null;
+
     public AbstractHighlighterBuilder() {}
 
     protected AbstractHighlighterBuilder(AbstractHighlighterBuilder<?> template, QueryBuilder queryBuilder) {
@@ -148,6 +155,7 @@ protected AbstractHighlighterBuilder(AbstractHighlighterBuilder<?> template, Que
         phraseLimit = template.phraseLimit;
         options = template.options;
         requireFieldMatch = template.requireFieldMatch;
+        maxAnalyzerOffset = template.maxAnalyzerOffset;
     }
 
     /**
@@ -179,7 +187,13 @@ protected AbstractHighlighterBuilder(StreamInput in) throws IOException {
         if (in.readBoolean()) {
             options(in.readMap());
         }
+
         requireFieldMatch(in.readOptionalBoolean());
+
+        if (in.getVersion().onOrAfter(Version.V_2_2_0)) {
+            maxAnalyzerOffset(in.readOptionalVInt());
+        }
+
     }
 
     /**
@@ -221,6 +235,9 @@ public final void writeTo(StreamOutput out) throws IOException {
             out.writeMap(options);
         }
         out.writeOptionalBoolean(requireFieldMatch);
+        if (out.getVersion().onOrAfter(Version.V_2_2_0)) {
+            out.writeOptionalVInt(maxAnalyzerOffset);
+        }
         doWriteTo(out);
     }
 
@@ -540,6 +557,21 @@ public Integer phraseLimit() {
         return this.phraseLimit;
     }
 
+    /**
+     * Sets the maximum offset for the highlighter
+     * @param maxAnalyzerOffset the maximum offset that the highlighter will consider
+     * @return this for chaining
+     */
+    @SuppressWarnings("unchecked")
+    public HB maxAnalyzerOffset(Integer maxAnalyzerOffset) {
+        this.maxAnalyzerOffset = maxAnalyzerOffset;
+        return (HB) this;
+    }
+
+    public Integer maxAnalyzerOffset() {
+        return this.maxAnalyzerOffset;
+    }
+
     /**
      * Forces the highlighting to highlight fields based on the source even if fields are stored separately.
      */
@@ -621,6 +653,10 @@ void commonOptionsToXContent(XContentBuilder builder) throws IOException {
         if (phraseLimit != null) {
             builder.field(PHRASE_LIMIT_FIELD.getPreferredName(), phraseLimit);
         }
+        if (maxAnalyzerOffset != null) {
+            builder.field(MAX_ANALYZER_OFFSET_FIELD.getPreferredName(), maxAnalyzerOffset);
+        }
+
     }
 
     static <HB extends AbstractHighlighterBuilder<HB>> BiFunction<XContentParser, HB, HB> setupParser(ObjectParser<HB, Void> parser) {
@@ -640,6 +676,7 @@ static <HB extends AbstractHighlighterBuilder<HB>> BiFunction<XContentParser, HB
         parser.declareInt(HB::noMatchSize, NO_MATCH_SIZE_FIELD);
         parser.declareBoolean(HB::forceSource, FORCE_SOURCE_FIELD);
         parser.declareInt(HB::phraseLimit, PHRASE_LIMIT_FIELD);
+        parser.declareInt(HB::maxAnalyzerOffset, MAX_ANALYZER_OFFSET_FIELD);
         parser.declareObject(HB::options, (XContentParser p, Void c) -> {
             try {
                 return p.map();
@@ -736,6 +773,6 @@ public final boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/CustomQueryScorer.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/CustomQueryScorer.java
index 48db8a7f68168..d0fb0f6da53c4 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/CustomQueryScorer.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/CustomQueryScorer.java
@@ -43,6 +43,11 @@
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Internally used for custom scoring
+ *
+ * @opensearch.internal
+ */
 public final class CustomQueryScorer extends QueryScorer {
 
     public CustomQueryScorer(Query query, IndexReader reader, String field, String defaultField) {
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FastVectorHighlighter.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FastVectorHighlighter.java
index e5bfb5d2c94c1..69f86bb91cc6e 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FastVectorHighlighter.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FastVectorHighlighter.java
@@ -47,8 +47,8 @@
 import org.apache.lucene.search.vectorhighlight.SingleFragListBuilder;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.TextSearchInfo;
 import org.opensearch.search.fetch.FetchSubPhase;
@@ -64,6 +64,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Uses Lucene's Fast Vector Highlighting
+ *
+ * @opensearch.internal
+ */
 public class FastVectorHighlighter implements Highlighter {
     private static final BoundaryScanner DEFAULT_SIMPLE_BOUNDARY_SCANNER = new SimpleBoundaryScanner();
     private static final BoundaryScanner DEFAULT_SENTENCE_BOUNDARY_SCANNER = new BreakIteratorBoundaryScanner(
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FieldHighlightContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FieldHighlightContext.java
index 5d2758a04e750..2b4587fe6f40f 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FieldHighlightContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FieldHighlightContext.java
@@ -38,6 +38,11 @@
 
 import java.util.Map;
 
+/**
+ * Context used during field level highlighting
+ *
+ * @opensearch.internal
+ */
 public class FieldHighlightContext {
 
     public final String fieldName;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FragmentBuilderHelper.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FragmentBuilderHelper.java
index 1b1931c171a5a..e037ae5544a07 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FragmentBuilderHelper.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/FragmentBuilderHelper.java
@@ -49,6 +49,8 @@
 
 /**
  * Simple helper class for {@link FastVectorHighlighter} {@link FragmentsBuilder} implementations.
+ *
+ * @opensearch.internal
  */
 public final class FragmentBuilderHelper {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilder.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilder.java
index 1d998eeb578fa..cc0723ed7a432 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilder.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilder.java
@@ -34,14 +34,14 @@
 
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.vectorhighlight.SimpleBoundaryScanner;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.NamedObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.NamedObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -60,13 +60,15 @@
 import java.util.Set;
 import java.util.function.BiFunction;
 
-import static org.opensearch.common.xcontent.ObjectParser.fromList;
+import static org.opensearch.core.xcontent.ObjectParser.fromList;
 
 /**
  * A builder for search highlighting. Settings can control how large fields
  * are summarized to show only selected snippets ("fragments") containing search terms.
  *
  * @see org.opensearch.search.builder.SearchSourceBuilder#highlight()
+ *
+ * @opensearch.internal
  */
 public class HighlightBuilder extends AbstractHighlighterBuilder<HighlightBuilder> {
     /** default for whether to highlight fields based on the source even if stored separately */
@@ -397,6 +399,10 @@ private static void transferOptions(
         if (highlighterBuilder.highlightQuery != null) {
             targetOptionsBuilder.highlightQuery(highlighterBuilder.highlightQuery.toQuery(context));
         }
+        if (highlighterBuilder.maxAnalyzerOffset != null) {
+            targetOptionsBuilder.maxAnalyzerOffset(highlighterBuilder.maxAnalyzerOffset);
+        }
+
     }
 
     static Character[] convertCharArray(char[] array) {
@@ -467,6 +473,11 @@ public HighlightBuilder rewrite(QueryRewriteContext ctx) throws IOException {
 
     }
 
+    /**
+     * Field for highlight builder
+     *
+     * @opensearch.internal
+     */
     public static class Field extends AbstractHighlighterBuilder<Field> {
         static final NamedObjectParser<Field, Void> PARSER;
         static {
@@ -570,6 +581,11 @@ public Field rewrite(QueryRewriteContext ctx) throws IOException {
         }
     }
 
+    /**
+     * Order for highlight builder
+     *
+     * @opensearch.internal
+     */
     public enum Order implements Writeable {
         NONE,
         SCORE;
@@ -596,6 +612,11 @@ public String toString() {
         }
     }
 
+    /**
+     * Boundary scanner type
+     *
+     * @opensearch.internal
+     */
     public enum BoundaryScannerType implements Writeable {
         CHARS,
         WORD,
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightField.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightField.java
index 9cdcee3bfe8ae..8f10aba54b7d5 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightField.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightField.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,10 +47,12 @@
 import java.util.List;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A field highlighted with its highlighted fragments.
+ *
+ * @opensearch.internal
  */
 public class HighlightField implements ToXContentFragment, Writeable {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightPhase.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightPhase.java
index 4673477ac1772..2fc9b214e3ebb 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightPhase.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightPhase.java
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.function.Function;
 
+/**
+ * Highlight Phase of the search request.
+ *
+ * @opensearch.internal
+ */
 public class HighlightPhase implements FetchSubPhase {
 
     private final Map<String, Highlighter> highlighters;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightUtils.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightUtils.java
index 3265a339595f5..2238554a12149 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightUtils.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/HighlightUtils.java
@@ -46,6 +46,11 @@
 
 import static java.util.Collections.singleton;
 
+/**
+ * Utility class used during the highlight phase of the search request.
+ *
+ * @opensearch.internal
+ */
 public final class HighlightUtils {
 
     // U+2029 PARAGRAPH SEPARATOR (PS): each value holds a discrete passage for highlighting (unified highlighter)
@@ -67,7 +72,7 @@ public static List<Object> loadFieldValues(
     ) throws IOException {
         if (forceSource == false && fieldType.isStored()) {
             CustomFieldsVisitor fieldVisitor = new CustomFieldsVisitor(singleton(fieldType.name()), false);
-            hitContext.reader().document(hitContext.docId(), fieldVisitor);
+            hitContext.reader().storedFields().document(hitContext.docId(), fieldVisitor);
             List<Object> textsToHighlight = fieldVisitor.fields().get(fieldType.name());
             return textsToHighlight != null ? textsToHighlight : Collections.emptyList();
         }
@@ -75,6 +80,11 @@ public static List<Object> loadFieldValues(
         return fetcher.fetchValues(hitContext.sourceLookup());
     }
 
+    /**
+     * Encoders for the highlighters
+     *
+     * @opensearch.internal
+     */
     public static class Encoders {
         public static final Encoder DEFAULT = new DefaultEncoder();
         public static final Encoder HTML = new SimpleHTMLEncoder();
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/Highlighter.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/Highlighter.java
index 417b2acd5fe24..0c9bffde6c517 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/Highlighter.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/Highlighter.java
@@ -37,6 +37,8 @@
 
 /**
  * Highlights a search result.
+ *
+ * @opensearch.internal
  */
 public interface Highlighter {
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighter.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighter.java
index d2699c650d887..eb5f4f3c14eb2 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighter.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighter.java
@@ -47,7 +47,7 @@
 import org.apache.lucene.search.highlight.TextFragment;
 import org.apache.lucene.util.BytesRefHash;
 import org.apache.lucene.util.CollectionUtil;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.search.fetch.FetchContext;
@@ -61,6 +61,11 @@
 
 import static org.opensearch.search.fetch.subphase.highlight.UnifiedHighlighter.convertFieldValue;
 
+/**
+ * Standard Lucene Highlighter implementation
+ *
+ * @opensearch.internal
+ */
 public class PlainHighlighter implements Highlighter {
     private static final String CACHE_KEY = "highlight-plain";
 
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SearchHighlightContext.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SearchHighlightContext.java
index 71c18d2217faa..7464ba094b97e 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SearchHighlightContext.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SearchHighlightContext.java
@@ -43,6 +43,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Search context used during highlighting phase
+ *
+ * @opensearch.internal
+ */
 public class SearchHighlightContext {
 
     private final Map<String, Field> fields;
@@ -74,6 +79,11 @@ public boolean forceSource(Field field) {
         return _field == null ? false : _field.fieldOptions.forceSource;
     }
 
+    /**
+     * Field for the search highlight context
+     *
+     * @opensearch.internal
+     */
     public static class Field {
         private final String field;
         private final FieldOptions fieldOptions;
@@ -94,6 +104,11 @@ public FieldOptions fieldOptions() {
         }
     }
 
+    /**
+     * Field options for the search highlight context
+     *
+     * @opensearch.internal
+     */
     public static class FieldOptions {
 
         // Field options that default to null or -1 are often set to their real default in HighlighterParseElement#parse
@@ -139,6 +154,12 @@ public static class FieldOptions {
 
         private int phraseLimit = -1;
 
+        private Integer maxAnalyzerOffset = null;
+
+        public Integer maxAnalyzerOffset() {
+            return maxAnalyzerOffset;
+        }
+
         public int fragmentCharSize() {
             return fragmentCharSize;
         }
@@ -318,6 +339,15 @@ Builder phraseLimit(int phraseLimit) {
                 return this;
             }
 
+            Builder maxAnalyzerOffset(Integer maxAnalyzerOffset) {
+                // throws an execption if the value is not a positive integer
+                if (maxAnalyzerOffset != null && maxAnalyzerOffset <= 0) {
+                    throw new IllegalArgumentException("the value [" + maxAnalyzerOffset + "] of max_analyzer_offset is invalid");
+                }
+                fieldOptions.maxAnalyzerOffset = maxAnalyzerOffset;
+                return this;
+            }
+
             Builder matchedFields(Set<String> matchedFields) {
                 fieldOptions.matchedFields = matchedFields;
                 return this;
@@ -390,6 +420,9 @@ Builder merge(FieldOptions globalOptions) {
                 if (fieldOptions.phraseLimit == -1) {
                     fieldOptions.phraseLimit = globalOptions.phraseLimit;
                 }
+                if (fieldOptions.maxAnalyzerOffset == null) {
+                    fieldOptions.maxAnalyzerOffset = globalOptions.maxAnalyzerOffset;
+                }
                 return this;
             }
         }
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SimpleFragmentsBuilder.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SimpleFragmentsBuilder.java
index 47a89b4699901..89da5f6edbdcf 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SimpleFragmentsBuilder.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SimpleFragmentsBuilder.java
@@ -40,6 +40,8 @@
 /**
  * Direct Subclass of Lucene's org.apache.lucene.search.vectorhighlight.SimpleFragmentsBuilder
  * that corrects offsets for broken analysis chains.
+ *
+ * @opensearch.internal
  */
 public class SimpleFragmentsBuilder extends org.apache.lucene.search.vectorhighlight.SimpleFragmentsBuilder {
     protected final MappedFieldType fieldType;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceScoreOrderFragmentsBuilder.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceScoreOrderFragmentsBuilder.java
index c62ef40a8771a..17866b0b69798 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceScoreOrderFragmentsBuilder.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceScoreOrderFragmentsBuilder.java
@@ -44,6 +44,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Internal builder used during source score lookup
+ *
+ * @opensearch.internal
+ */
 public class SourceScoreOrderFragmentsBuilder extends ScoreOrderFragmentsBuilder {
 
     private final MappedFieldType fieldType;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceSimpleFragmentsBuilder.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceSimpleFragmentsBuilder.java
index aae0c78ed0741..838883b18f762 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceSimpleFragmentsBuilder.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/SourceSimpleFragmentsBuilder.java
@@ -41,6 +41,11 @@
 import java.io.IOException;
 import java.util.List;
 
+/**
+ * Internal builder used during simple highlighting
+ *
+ * @opensearch.internal
+ */
 public class SourceSimpleFragmentsBuilder extends SimpleFragmentsBuilder {
 
     private final SourceLookup sourceLookup;
diff --git a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/UnifiedHighlighter.java b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/UnifiedHighlighter.java
index 8e97fc3a27ffb..df85246a84d54 100644
--- a/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/UnifiedHighlighter.java
+++ b/server/src/main/java/org/opensearch/search/fetch/subphase/highlight/UnifiedHighlighter.java
@@ -32,6 +32,8 @@
 package org.opensearch.search.fetch.subphase.highlight;
 
 import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.analysis.AnalyzerWrapper;
+import org.apache.lucene.analysis.miscellaneous.LimitTokenOffsetFilter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.highlight.Encoder;
 import org.apache.lucene.search.uhighlight.BoundedBreakIteratorScanner;
@@ -44,8 +46,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.Strings;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -66,6 +68,11 @@
 
 import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 
+/**
+ * Uses lucene's unified highlighter implementation
+ *
+ * @opensearch.internal
+ */
 public class UnifiedHighlighter implements Highlighter {
     @Override
     public boolean canHighlight(MappedFieldType fieldType) {
@@ -128,13 +135,33 @@ public HighlightField highlight(FieldHighlightContext fieldContext) throws IOExc
         return new HighlightField(fieldContext.fieldName, Text.convertFromStringArray(fragments));
     }
 
+    public AnalyzerWrapper getLimitedOffsetAnalyzer(Analyzer analyzer, int limit) {
+        return new AnalyzerWrapper(analyzer.getReuseStrategy()) {
+            @Override
+            protected Analyzer getWrappedAnalyzer(String fieldName) {
+                return analyzer;
+            }
+
+            @Override
+            protected TokenStreamComponents wrapComponents(String fieldName, TokenStreamComponents components) {
+                return new TokenStreamComponents(components.getSource(), new LimitTokenOffsetFilter(components.getTokenStream(), limit));
+            }
+
+        };
+
+    }
+
     CustomUnifiedHighlighter buildHighlighter(FieldHighlightContext fieldContext) throws IOException {
         Encoder encoder = fieldContext.field.fieldOptions().encoder().equals("html")
             ? HighlightUtils.Encoders.HTML
             : HighlightUtils.Encoders.DEFAULT;
         int maxAnalyzedOffset = fieldContext.context.getIndexSettings().getHighlightMaxAnalyzedOffset();
+        Integer fieldMaxAnalyzedOffset = fieldContext.field.fieldOptions().maxAnalyzerOffset();
         int numberOfFragments = fieldContext.field.fieldOptions().numberOfFragments();
         Analyzer analyzer = getAnalyzer(fieldContext.context.mapperService().documentMapper());
+        if (fieldMaxAnalyzedOffset != null) {
+            analyzer = getLimitedOffsetAnalyzer(analyzer, fieldMaxAnalyzedOffset);
+        }
         PassageFormatter passageFormatter = getPassageFormatter(fieldContext.hitContext, fieldContext.field, encoder);
         IndexSearcher searcher = fieldContext.context.searcher();
         OffsetSource offsetSource = getOffsetSource(fieldContext.fieldType);
@@ -169,7 +196,8 @@ CustomUnifiedHighlighter buildHighlighter(FieldHighlightContext fieldContext) th
             fieldContext.field.fieldOptions().noMatchSize(),
             higlighterNumberOfFragments,
             fieldMatcher(fieldContext),
-            maxAnalyzedOffset
+            maxAnalyzedOffset,
+            fieldMaxAnalyzedOffset
         );
     }
 
diff --git a/server/src/main/java/org/opensearch/search/internal/AliasFilter.java b/server/src/main/java/org/opensearch/search/internal/AliasFilter.java
index b4864a9beddb0..c1d425078049c 100644
--- a/server/src/main/java/org/opensearch/search/internal/AliasFilter.java
+++ b/server/src/main/java/org/opensearch/search/internal/AliasFilter.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.internal;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.Rewriteable;
@@ -46,6 +46,8 @@
 
 /**
  * Represents a {@link QueryBuilder} and a list of alias names that filters the builder is composed of.
+ *
+ * @opensearch.internal
  */
 public final class AliasFilter implements Writeable, Rewriteable<AliasFilter> {
 
diff --git a/server/src/main/java/org/opensearch/search/internal/CancellableBulkScorer.java b/server/src/main/java/org/opensearch/search/internal/CancellableBulkScorer.java
index 2999f5aa5476f..585d0baba8717 100644
--- a/server/src/main/java/org/opensearch/search/internal/CancellableBulkScorer.java
+++ b/server/src/main/java/org/opensearch/search/internal/CancellableBulkScorer.java
@@ -42,6 +42,8 @@
 /**
  * A {@link BulkScorer} wrapper that runs a {@link Runnable} on a regular basis
  * so that the query can be interrupted.
+ *
+ * @opensearch.internal
  */
 final class CancellableBulkScorer extends BulkScorer {
 
diff --git a/server/src/main/java/org/opensearch/search/internal/ContextIndexSearcher.java b/server/src/main/java/org/opensearch/search/internal/ContextIndexSearcher.java
index 2cc15d4c65b96..6fb3a314efcf5 100644
--- a/server/src/main/java/org/opensearch/search/internal/ContextIndexSearcher.java
+++ b/server/src/main/java/org/opensearch/search/internal/ContextIndexSearcher.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.internal;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -65,13 +67,18 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.SearchBootstrapSettings;
+import org.opensearch.search.SearchService;
 import org.opensearch.search.dfs.AggregatedDfs;
 import org.opensearch.search.profile.ContextualProfileBreakdown;
 import org.opensearch.search.profile.Timer;
 import org.opensearch.search.profile.query.ProfileWeight;
 import org.opensearch.search.profile.query.QueryProfiler;
 import org.opensearch.search.profile.query.QueryTimingType;
+import org.opensearch.search.query.QueryPhase;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.sort.FieldSortBuilder;
+import org.opensearch.search.sort.MinAndMax;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -84,27 +91,22 @@
 
 /**
  * Context-aware extension of {@link IndexSearcher}.
+ *
+ * @opensearch.internal
  */
 public class ContextIndexSearcher extends IndexSearcher implements Releasable {
+
+    private static final Logger logger = LogManager.getLogger(ContextIndexSearcher.class);
     /**
      * The interval at which we check for search cancellation when we cannot use
      * a {@link CancellableBulkScorer}. See {@link #intersectScorerAndBitSet}.
      */
-    private static int CHECK_CANCELLED_SCORER_INTERVAL = 1 << 11;
+    private static final int CHECK_CANCELLED_SCORER_INTERVAL = 1 << 11;
 
     private AggregatedDfs aggregatedDfs;
     private QueryProfiler profiler;
     private MutableQueryTimeout cancellable;
-
-    public ContextIndexSearcher(
-        IndexReader reader,
-        Similarity similarity,
-        QueryCache queryCache,
-        QueryCachingPolicy queryCachingPolicy,
-        boolean wrapWithExitableDirectoryReader
-    ) throws IOException {
-        this(reader, similarity, queryCache, queryCachingPolicy, new MutableQueryTimeout(), wrapWithExitableDirectoryReader, null);
-    }
+    private SearchContext searchContext;
 
     public ContextIndexSearcher(
         IndexReader reader,
@@ -112,9 +114,19 @@ public ContextIndexSearcher(
         QueryCache queryCache,
         QueryCachingPolicy queryCachingPolicy,
         boolean wrapWithExitableDirectoryReader,
-        Executor executor
+        Executor executor,
+        SearchContext searchContext
     ) throws IOException {
-        this(reader, similarity, queryCache, queryCachingPolicy, new MutableQueryTimeout(), wrapWithExitableDirectoryReader, executor);
+        this(
+            reader,
+            similarity,
+            queryCache,
+            queryCachingPolicy,
+            new MutableQueryTimeout(),
+            wrapWithExitableDirectoryReader,
+            executor,
+            searchContext
+        );
     }
 
     private ContextIndexSearcher(
@@ -124,13 +136,15 @@ private ContextIndexSearcher(
         QueryCachingPolicy queryCachingPolicy,
         MutableQueryTimeout cancellable,
         boolean wrapWithExitableDirectoryReader,
-        Executor executor
+        Executor executor,
+        SearchContext searchContext
     ) throws IOException {
         super(wrapWithExitableDirectoryReader ? new ExitableDirectoryReader((DirectoryReader) reader, cancellable) : reader, executor);
         setSimilarity(similarity);
         setQueryCache(queryCache);
         setQueryCachingPolicy(queryCachingPolicy);
         this.cancellable = cancellable;
+        this.searchContext = searchContext;
     }
 
     public void setProfiler(QueryProfiler profiler) {
@@ -233,11 +247,41 @@ public void search(
         result.topDocs(new TopDocsAndMaxScore(mergedTopDocs, Float.NaN), formats);
     }
 
+    public void search(
+        Query query,
+        CollectorManager<?, TopFieldDocs> manager,
+        QuerySearchResult result,
+        DocValueFormat[] formats,
+        TotalHits totalHits
+    ) throws IOException {
+        TopFieldDocs mergedTopDocs = search(query, manager);
+        // Lucene sets shards indexes during merging of topDocs from different collectors
+        // We need to reset shard index; OpenSearch will set shard index later during reduce stage
+        for (ScoreDoc scoreDoc : mergedTopDocs.scoreDocs) {
+            scoreDoc.shardIndex = -1;
+        }
+        if (totalHits != null) { // we have already precalculated totalHits for the whole index
+            mergedTopDocs = new TopFieldDocs(totalHits, mergedTopDocs.scoreDocs, mergedTopDocs.fields);
+        }
+        result.topDocs(new TopDocsAndMaxScore(mergedTopDocs, Float.NaN), formats);
+    }
+
     @Override
     protected void search(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
-        for (LeafReaderContext ctx : leaves) { // search each subreader
-            searchLeaf(ctx, weight, collector);
+        // Time series based workload by default traverses segments in desc order i.e. latest to the oldest order.
+        // This is actually beneficial for search queries to start search on latest segments first for time series workload.
+        // That can slow down ASC order queries on timestamp workload. So to avoid that slowdown, we will reverse leaf
+        // reader order here.
+        if (searchContext.shouldUseTimeSeriesDescSortOptimization()) {
+            for (int i = leaves.size() - 1; i >= 0; i--) {
+                searchLeaf(leaves.get(i), weight, collector);
+            }
+        } else {
+            for (int i = 0; i < leaves.size(); i++) {
+                searchLeaf(leaves.get(i), weight, collector);
+            }
         }
+        searchContext.bucketCollectorProcessor().processPostCollection(collector);
     }
 
     /**
@@ -247,16 +291,28 @@ protected void search(List<LeafReaderContext> leaves, Weight weight, Collector c
      * the provided <code>ctx</code>.
      */
     private void searchLeaf(LeafReaderContext ctx, Weight weight, Collector collector) throws IOException {
-        cancellable.checkCancelled();
-        weight = wrapWeight(weight);
+
+        // Check if at all we need to call this leaf for collecting results.
+        if (canMatch(ctx) == false) {
+            return;
+        }
+
         final LeafCollector leafCollector;
         try {
+            cancellable.checkCancelled();
+            weight = wrapWeight(weight);
+            // See please https://github.com/apache/lucene/pull/964
+            collector.setWeight(weight);
             leafCollector = collector.getLeafCollector(ctx);
         } catch (CollectionTerminatedException e) {
             // there is no doc of interest in this reader context
             // continue with the following leaf
             return;
+        } catch (QueryPhase.TimeExceededException e) {
+            searchContext.setSearchTimedOut(true);
+            return;
         }
+        // catch early terminated exception and rethrow?
         Bits liveDocs = ctx.reader().getLiveDocs();
         BitSet liveDocsBitSet = getSparseBitSetOrNull(liveDocs);
         if (liveDocsBitSet == null) {
@@ -267,6 +323,9 @@ private void searchLeaf(LeafReaderContext ctx, Weight weight, Collector collecto
                 } catch (CollectionTerminatedException e) {
                     // collection was terminated prematurely
                     // continue with the following leaf
+                } catch (QueryPhase.TimeExceededException e) {
+                    searchContext.setSearchTimedOut(true);
+                    return;
                 }
             }
         } else {
@@ -283,6 +342,9 @@ private void searchLeaf(LeafReaderContext ctx, Weight weight, Collector collecto
                 } catch (CollectionTerminatedException e) {
                     // collection was terminated prematurely
                     // continue with the following leaf
+                } catch (QueryPhase.TimeExceededException e) {
+                    searchContext.setSearchTimedOut(true);
+                    return;
                 }
             }
         }
@@ -382,6 +444,18 @@ public CollectionStatistics collectionStatistics(String field) throws IOExceptio
         return collectionStatistics;
     }
 
+    /**
+     * Compute the leaf slices that will be used by concurrent segment search to spread work across threads
+     * @param leaves all the segments
+     * @return leafSlice group to be executed by different threads
+     */
+    @Override
+    protected LeafSlice[] slices(List<LeafReaderContext> leaves) {
+        // For now using the static setting to get the targetMaxSlice value. It will be updated to dynamic mechanism as part of
+        // https://github.com/opensearch-project/OpenSearch/issues/8870 when lucene changes are available
+        return slicesInternal(leaves, SearchBootstrapSettings.getTargetMaxSlice());
+    }
+
     public DirectoryReader getDirectoryReader() {
         final IndexReader reader = getIndexReader();
         assert reader instanceof DirectoryReader : "expected an instance of DirectoryReader, got " + reader.getClass();
@@ -421,7 +495,44 @@ public void clear() {
         }
     }
 
-    public boolean allowConcurrentSegmentSearch() {
-        return (getExecutor() != null);
+    private boolean canMatch(LeafReaderContext ctx) throws IOException {
+        // skip segments for search after if min/max of them doesn't qualify competitive
+        return canMatchSearchAfter(ctx);
+    }
+
+    private boolean canMatchSearchAfter(LeafReaderContext ctx) throws IOException {
+        if (searchContext.request() != null && searchContext.request().source() != null) {
+            // Only applied on primary sort field and primary search_after.
+            FieldSortBuilder primarySortField = FieldSortBuilder.getPrimaryFieldSortOrNull(searchContext.request().source());
+            if (primarySortField != null) {
+                MinAndMax<?> minMax = FieldSortBuilder.getMinMaxOrNullForSegment(
+                    this.searchContext.getQueryShardContext(),
+                    ctx,
+                    primarySortField
+                );
+                return SearchService.canMatchSearchAfter(
+                    searchContext.searchAfter(),
+                    minMax,
+                    primarySortField,
+                    searchContext.trackTotalHitsUpTo()
+                );
+            }
+        }
+        return true;
+    }
+
+    // package-private for testing
+    LeafSlice[] slicesInternal(List<LeafReaderContext> leaves, int targetMaxSlice) {
+        LeafSlice[] leafSlices;
+        if (targetMaxSlice == 0) {
+            // use the default lucene slice calculation
+            leafSlices = super.slices(leaves);
+            logger.debug("Slice count using lucene default [{}]", leafSlices.length);
+        } else {
+            // use the custom slice calculation based on targetMaxSlice
+            leafSlices = MaxTargetSliceSupplier.getSlices(leaves, targetMaxSlice);
+            logger.debug("Slice count using max target slice supplier [{}]", leafSlices.length);
+        }
+        return leafSlices;
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/internal/ExitableDirectoryReader.java b/server/src/main/java/org/opensearch/search/internal/ExitableDirectoryReader.java
index 9664fe3cb9085..83ecd11a493ef 100644
--- a/server/src/main/java/org/opensearch/search/internal/ExitableDirectoryReader.java
+++ b/server/src/main/java/org/opensearch/search/internal/ExitableDirectoryReader.java
@@ -51,6 +51,8 @@
 /**
  * Wraps an {@link IndexReader} with a {@link QueryCancellation}
  * which checks for cancelled or timed-out query.
+ *
+ * @opensearch.internal
  */
 class ExitableDirectoryReader extends FilterDirectoryReader {
 
diff --git a/server/src/main/java/org/opensearch/search/internal/FilteredSearchContext.java b/server/src/main/java/org/opensearch/search/internal/FilteredSearchContext.java
index 6d77558ec3bd0..55b1eb30a8f27 100644
--- a/server/src/main/java/org/opensearch/search/internal/FilteredSearchContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/FilteredSearchContext.java
@@ -33,6 +33,7 @@
 package org.opensearch.search.internal;
 
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.Query;
 import org.opensearch.action.search.SearchShardTask;
@@ -49,6 +50,8 @@
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchShardTarget;
+import org.opensearch.search.aggregations.BucketCollectorProcessor;
+import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.SearchContextAggregations;
 import org.opensearch.search.collapse.CollapseContext;
 import org.opensearch.search.dfs.DfsSearchResult;
@@ -61,6 +64,7 @@
 import org.opensearch.search.fetch.subphase.highlight.SearchHighlightContext;
 import org.opensearch.search.profile.Profilers;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.query.ReduceableSearchResult;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.sort.SortAndFormats;
 import org.opensearch.search.suggest.SuggestionSearchContext;
@@ -68,6 +72,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Context used during a filtered search
+ *
+ * @opensearch.internal
+ */
 public abstract class FilteredSearchContext extends SearchContext {
 
     private final SearchContext in;
@@ -492,8 +501,8 @@ public Profilers getProfilers() {
     }
 
     @Override
-    public Map<Class<?>, Collector> queryCollectors() {
-        return in.queryCollectors();
+    public Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers() {
+        return in.queryCollectorManagers();
     }
 
     @Override
@@ -535,4 +544,29 @@ public void addRescore(RescoreContext rescore) {
     public ReaderContext readerContext() {
         return in.readerContext();
     }
+
+    @Override
+    public InternalAggregation.ReduceContext partialOnShard() {
+        return in.partialOnShard();
+    }
+
+    @Override
+    public void setBucketCollectorProcessor(BucketCollectorProcessor bucketCollectorProcessor) {
+        in.setBucketCollectorProcessor(bucketCollectorProcessor);
+    }
+
+    @Override
+    public BucketCollectorProcessor bucketCollectorProcessor() {
+        return in.bucketCollectorProcessor();
+    }
+
+    @Override
+    public boolean shouldUseConcurrentSearch() {
+        return in.shouldUseConcurrentSearch();
+    }
+
+    @Override
+    public boolean shouldUseTimeSeriesDescSortOptimization() {
+        return in.shouldUseTimeSeriesDescSortOptimization();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/internal/InternalScrollSearchRequest.java b/server/src/main/java/org/opensearch/search/internal/InternalScrollSearchRequest.java
index afa4dc7be7bf2..e458f7f38eac4 100644
--- a/server/src/main/java/org/opensearch/search/internal/InternalScrollSearchRequest.java
+++ b/server/src/main/java/org/opensearch/search/internal/InternalScrollSearchRequest.java
@@ -34,16 +34,21 @@
 
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.action.search.SearchShardTask;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.Scroll;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Internal request used during scroll search
+ *
+ * @opensearch.internal
+ */
 public class InternalScrollSearchRequest extends TransportRequest {
 
     private ShardSearchContextId contextId;
diff --git a/server/src/main/java/org/opensearch/search/internal/InternalSearchResponse.java b/server/src/main/java/org/opensearch/search/internal/InternalSearchResponse.java
index 0f64adb37ab95..3af8fc3854cf1 100644
--- a/server/src/main/java/org/opensearch/search/internal/InternalSearchResponse.java
+++ b/server/src/main/java/org/opensearch/search/internal/InternalSearchResponse.java
@@ -32,20 +32,26 @@
 
 package org.opensearch.search.internal;
 
+import org.opensearch.Version;
 import org.opensearch.action.search.SearchResponseSections;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.profile.SearchProfileShardResults;
 import org.opensearch.search.suggest.Suggest;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
 
 /**
  * {@link SearchResponseSections} subclass that can be serialized over the wire.
+ *
+ * @opensearch.internal
  */
 public class InternalSearchResponse extends SearchResponseSections implements Writeable, ToXContentFragment {
     public static InternalSearchResponse empty() {
@@ -65,7 +71,20 @@ public InternalSearchResponse(
         Boolean terminatedEarly,
         int numReducePhases
     ) {
-        super(hits, aggregations, suggest, timedOut, terminatedEarly, profileResults, numReducePhases);
+        this(hits, aggregations, suggest, profileResults, timedOut, terminatedEarly, numReducePhases, Collections.emptyList());
+    }
+
+    public InternalSearchResponse(
+        SearchHits hits,
+        InternalAggregations aggregations,
+        Suggest suggest,
+        SearchProfileShardResults profileResults,
+        boolean timedOut,
+        Boolean terminatedEarly,
+        int numReducePhases,
+        List<SearchExtBuilder> searchExtBuilderList
+    ) {
+        super(hits, aggregations, suggest, timedOut, terminatedEarly, profileResults, numReducePhases, searchExtBuilderList);
     }
 
     public InternalSearchResponse(StreamInput in) throws IOException {
@@ -76,7 +95,8 @@ public InternalSearchResponse(StreamInput in) throws IOException {
             in.readBoolean(),
             in.readOptionalBoolean(),
             in.readOptionalWriteable(SearchProfileShardResults::new),
-            in.readVInt()
+            in.readVInt(),
+            readSearchExtBuildersOnOrAfter(in)
         );
     }
 
@@ -89,5 +109,16 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalBoolean(terminatedEarly);
         out.writeOptionalWriteable(profileResults);
         out.writeVInt(numReducePhases);
+        writeSearchExtBuildersOnOrAfter(out, searchExtBuilders);
+    }
+
+    private static List<SearchExtBuilder> readSearchExtBuildersOnOrAfter(StreamInput in) throws IOException {
+        return (in.getVersion().onOrAfter(Version.V_2_10_0)) ? in.readNamedWriteableList(SearchExtBuilder.class) : Collections.emptyList();
+    }
+
+    private static void writeSearchExtBuildersOnOrAfter(StreamOutput out, List<SearchExtBuilder> searchExtBuilders) throws IOException {
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeNamedWriteableList(searchExtBuilders);
+        }
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/internal/LegacyReaderContext.java b/server/src/main/java/org/opensearch/search/internal/LegacyReaderContext.java
index 7c3b36e9e55f9..05ab12d5ae809 100644
--- a/server/src/main/java/org/opensearch/search/internal/LegacyReaderContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/LegacyReaderContext.java
@@ -40,6 +40,11 @@
 
 import java.util.Objects;
 
+/**
+ * Reader context that does not hold a reference to a point in time Searcher
+ *
+ * @opensearch.internal
+ */
 public class LegacyReaderContext extends ReaderContext {
     private final ShardSearchRequest shardSearchRequest;
     private final ScrollContext scrollContext;
diff --git a/server/src/main/java/org/opensearch/search/internal/MaxTargetSliceSupplier.java b/server/src/main/java/org/opensearch/search/internal/MaxTargetSliceSupplier.java
new file mode 100644
index 0000000000000..4b20ae6e771ea
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/internal/MaxTargetSliceSupplier.java
@@ -0,0 +1,55 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.internal;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.IndexSearcher;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * Supplier to compute leaf slices based on passed in leaves and max target slice count to limit the number of computed slices. It sorts
+ * all the leaves based on document count and then assign each leaf in round-robin fashion to the target slice count slices. Based on
+ * experiment results as shared in <a href=https://github.com/opensearch-project/OpenSearch/issues/7358>issue-7358</a>
+ * we can see this mechanism helps to achieve better tail/median latency over default lucene slice computation.
+ *
+ * @opensearch.internal
+ */
+final class MaxTargetSliceSupplier {
+
+    static IndexSearcher.LeafSlice[] getSlices(List<LeafReaderContext> leaves, int targetMaxSlice) {
+        if (targetMaxSlice <= 0) {
+            throw new IllegalArgumentException("MaxTargetSliceSupplier called with unexpected slice count of " + targetMaxSlice);
+        }
+
+        // slice count should not exceed the segment count
+        int targetSliceCount = Math.min(targetMaxSlice, leaves.size());
+
+        // Make a copy so we can sort:
+        List<LeafReaderContext> sortedLeaves = new ArrayList<>(leaves);
+
+        // Sort by maxDoc, descending:
+        sortedLeaves.sort(Collections.reverseOrder(Comparator.comparingInt(l -> l.reader().maxDoc())));
+
+        final List<List<LeafReaderContext>> groupedLeaves = new ArrayList<>();
+        for (int i = 0; i < targetSliceCount; ++i) {
+            groupedLeaves.add(new ArrayList<>());
+        }
+        // distribute the slices in round-robin fashion
+        for (int idx = 0; idx < sortedLeaves.size(); ++idx) {
+            int currentGroup = idx % targetSliceCount;
+            groupedLeaves.get(currentGroup).add(sortedLeaves.get(idx));
+        }
+
+        return groupedLeaves.stream().map(IndexSearcher.LeafSlice::new).toArray(IndexSearcher.LeafSlice[]::new);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java b/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java
new file mode 100644
index 0000000000000..5c2a9f82f98e4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java
@@ -0,0 +1,94 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.internal;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lease.Releasables;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.Segment;
+import org.opensearch.index.shard.IndexShard;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * PIT reader context containing PIT specific information such as pit id, create time etc.
+ */
+public class PitReaderContext extends ReaderContext {
+
+    // Storing the encoded PIT ID as part of PIT reader context for use cases such as list pit API
+    private final SetOnce<String> pitId = new SetOnce<>();
+    // Creation time of PIT contexts which helps users to differentiate between multiple PIT reader contexts
+    private final SetOnce<Long> creationTime = new SetOnce<>();
+    /**
+     * Shard routing at the time of creation of PIT Reader Context
+     */
+    private final ShardRouting shardRouting;
+
+    /**
+     * Encapsulates segments constituting the shard at the time of creation of PIT Reader Context.
+     */
+    private final List<Segment> segments;
+
+    public PitReaderContext(
+        ShardSearchContextId id,
+        IndexService indexService,
+        IndexShard indexShard,
+        Engine.SearcherSupplier searcherSupplier,
+        long keepAliveInMillis,
+        boolean singleSession
+    ) {
+        super(id, indexService, indexShard, searcherSupplier, keepAliveInMillis, singleSession);
+        shardRouting = indexShard.routingEntry();
+        segments = indexShard.segments(true);
+    }
+
+    public String getPitId() {
+        return this.pitId.get();
+    }
+
+    public void setPitId(final String pitId) {
+        this.pitId.set(pitId);
+    }
+
+    /**
+     * Returns a releasable to indicate that the caller has stopped using this reader.
+     * The pit id can be updated and time to live of the reader usage can be extended using the provided
+     * <code>keepAliveInMillis</code>.
+     */
+    public Releasable updatePitIdAndKeepAlive(long keepAliveInMillis, String pitId, long createTime) {
+        getRefCounted().incRef();
+        tryUpdateKeepAlive(keepAliveInMillis);
+        setPitId(pitId);
+        setCreationTime(createTime);
+        return Releasables.releaseOnce(() -> {
+            updateLastAccessTime();
+            getRefCounted().decRef();
+        });
+    }
+
+    public long getCreationTime() {
+        return this.creationTime.get() == null ? 0 : this.creationTime.get();
+    }
+
+    public void setCreationTime(final long creationTime) {
+        this.creationTime.set(creationTime);
+    }
+
+    public ShardRouting getShardRouting() {
+        return shardRouting;
+    }
+
+    public List<Segment> getSegments() {
+        return Collections.unmodifiableList(segments);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/internal/ReaderContext.java b/server/src/main/java/org/opensearch/search/internal/ReaderContext.java
index 31d7a44d9bbd2..898aa2e2c6745 100644
--- a/server/src/main/java/org/opensearch/search/internal/ReaderContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/ReaderContext.java
@@ -56,6 +56,8 @@
  * in {@link org.opensearch.search.SearchService} a SearchContext can be closed concurrently due to independent events
  * ie. when an index gets removed. To prevent accessing closed IndexReader / IndexSearcher instances the SearchContext
  * can be guarded by a reference count and fail if it's been closed by an external event.
+ *
+ * @opensearch.internal
  */
 public class ReaderContext implements Releasable {
     private final ShardSearchContextId id;
@@ -103,10 +105,22 @@ public void validate(TransportRequest request) {
         indexShard.getSearchOperationListener().validateReaderContext(this, request);
     }
 
-    private long nowInMillis() {
+    protected AbstractRefCounted getRefCounted() {
+        return refCounted;
+    }
+
+    protected void updateLastAccessTime() {
+        this.lastAccessTime.updateAndGet(curr -> Math.max(curr, nowInMillis()));
+    }
+
+    protected long nowInMillis() {
         return indexShard.getThreadPool().relativeTimeInMillis();
     }
 
+    public long getKeepAlive() {
+        return keepAlive.get();
+    }
+
     @Override
     public final void close() {
         if (closed.compareAndSet(false, true)) {
@@ -138,7 +152,10 @@ public Engine.Searcher acquireSearcher(String source) {
         return searcherSupplier.acquireSearcher(source);
     }
 
-    private void tryUpdateKeepAlive(long keepAlive) {
+    /**
+     * Update keep alive if it is greater than current keep alive
+     */
+    public void tryUpdateKeepAlive(long keepAlive) {
         this.keepAlive.updateAndGet(curr -> Math.max(curr, keepAlive));
     }
 
diff --git a/server/src/main/java/org/opensearch/search/internal/ScrollContext.java b/server/src/main/java/org/opensearch/search/internal/ScrollContext.java
index 2df274d373bcb..ae4074930e0c0 100644
--- a/server/src/main/java/org/opensearch/search/internal/ScrollContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/ScrollContext.java
@@ -36,7 +36,11 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.search.Scroll;
 
-/** Wrapper around information that needs to stay around when scrolling. */
+/**
+ * Wrapper around information that needs to stay around when scrolling.
+ *
+ * @opensearch.internal
+ */
 public final class ScrollContext {
     public TotalHits totalHits = null;
     public float maxScore = Float.NaN;
diff --git a/server/src/main/java/org/opensearch/search/internal/SearchContext.java b/server/src/main/java/org/opensearch/search/internal/SearchContext.java
index 7ff0eaed4be63..b13f4f8dab2be 100644
--- a/server/src/main/java/org/opensearch/search/internal/SearchContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/SearchContext.java
@@ -32,8 +32,10 @@
 package org.opensearch.search.internal;
 
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.Nullable;
@@ -52,7 +54,12 @@
 import org.opensearch.search.RescoreDocIds;
 import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchShardTarget;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.BucketCollectorProcessor;
+import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.SearchContextAggregations;
+import org.opensearch.search.aggregations.bucket.LocalBucketCountThresholds;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.opensearch.search.collapse.CollapseContext;
 import org.opensearch.search.dfs.DfsSearchResult;
 import org.opensearch.search.fetch.FetchPhase;
@@ -66,10 +73,12 @@
 import org.opensearch.search.fetch.subphase.highlight.SearchHighlightContext;
 import org.opensearch.search.profile.Profilers;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.query.ReduceableSearchResult;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.sort.SortAndFormats;
 import org.opensearch.search.suggest.SuggestionSearchContext;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -81,6 +90,8 @@
  * This class encapsulates the state needed to execute a search. It holds a reference to the
  * shards point in time snapshot (IndexReader / ContextIndexSearcher) and allows passing on
  * state from one query / fetch phase to another.
+ *
+ * @opensearch.internal
  */
 public abstract class SearchContext implements Releasable {
 
@@ -89,10 +100,26 @@ public abstract class SearchContext implements Releasable {
     public static final int TRACK_TOTAL_HITS_DISABLED = -1;
     public static final int DEFAULT_TRACK_TOTAL_HITS_UP_TO = 10000;
 
+    // no-op bucket collector processor
+    public static final BucketCollectorProcessor NO_OP_BUCKET_COLLECTOR_PROCESSOR = new BucketCollectorProcessor() {
+        @Override
+        public void processPostCollection(Collector collectorTree) {
+            // do nothing as there is no aggregation collector
+        }
+
+        @Override
+        public List<Aggregator> toAggregators(Collection<Collector> collectors) {
+            // should not be called when there is no aggregation collector
+            throw new IllegalStateException("Unexpected toAggregators call on NO_OP_BUCKET_COLLECTOR_PROCESSOR");
+        }
+    };
+
     private final List<Releasable> releasables = new CopyOnWriteArrayList<>();
     private final AtomicBoolean closed = new AtomicBoolean(false);
     private InnerHitsContext innerHitsContext;
 
+    private volatile boolean searchTimedOut;
+
     protected SearchContext() {}
 
     public abstract void setTask(SearchShardTask task);
@@ -101,6 +128,14 @@ protected SearchContext() {}
 
     public abstract boolean isCancelled();
 
+    public boolean isSearchTimedOut() {
+        return this.searchTimedOut;
+    }
+
+    public void setSearchTimedOut(boolean searchTimedOut) {
+        this.searchTimedOut = searchTimedOut;
+    }
+
     @Override
     public final void close() {
         if (closed.compareAndSet(false, true)) {
@@ -361,6 +396,24 @@ public final void assignRescoreDocIds(RescoreDocIds rescoreDocIds) {
      */
     public abstract Profilers getProfilers();
 
+    /**
+     * Returns concurrent segment search status for the search context
+     */
+    public boolean shouldUseConcurrentSearch() {
+        return false;
+    }
+
+    /**
+     * Returns local bucket count thresholds based on concurrent segment search status
+     */
+    public LocalBucketCountThresholds asLocalBucketCountThresholds(TermsAggregator.BucketCountThresholds bucketCountThresholds) {
+        if (shouldUseConcurrentSearch()) {
+            return new LocalBucketCountThresholds(0, ArrayUtil.MAX_ARRAY_LENGTH - 1);
+        } else {
+            return new LocalBucketCountThresholds(bucketCountThresholds.getShardMinDocCount(), bucketCountThresholds.getShardSize());
+        }
+    }
+
     /**
      * Adds a releasable that will be freed when this context is closed.
      */
@@ -384,12 +437,26 @@ public final boolean hasOnlySuggest() {
 
     /**
      * Returns time in milliseconds that can be used for relative time calculations.
-     * WARN: This is not the epoch time.
+     * WARN: This is not the epoch time and can be a cached time.
      */
     public abstract long getRelativeTimeInMillis();
 
-    /** Return a view of the additional query collectors that should be run for this context. */
-    public abstract Map<Class<?>, Collector> queryCollectors();
+    /**
+     * Returns time in milliseconds that can be used for relative time calculations. this method will fall back to
+     * {@link SearchContext#getRelativeTimeInMillis()} (which might be a cached time) if useCache was set to true else it will be just be a
+     * wrapper of {@link System#nanoTime()} converted to milliseconds.
+     * @param useCache to allow using cached time if true or forcing calling {@link System#nanoTime()} if false
+     * @return Returns time in milliseconds that can be used for relative time calculations.
+     */
+    public long getRelativeTimeInMillis(boolean useCache) {
+        if (useCache) {
+            return getRelativeTimeInMillis();
+        }
+        return TimeValue.nsecToMSec(System.nanoTime());
+    }
+
+    /** Return a view of the additional query collector managers that should be run for this context. */
+    public abstract Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers();
 
     public abstract QueryShardContext getQueryShardContext();
 
@@ -411,4 +478,13 @@ public String toString() {
     }
 
     public abstract ReaderContext readerContext();
+
+    public abstract InternalAggregation.ReduceContext partialOnShard();
+
+    // processor used for bucket collectors
+    public abstract void setBucketCollectorProcessor(BucketCollectorProcessor bucketCollectorProcessor);
+
+    public abstract BucketCollectorProcessor bucketCollectorProcessor();
+
+    public abstract boolean shouldUseTimeSeriesDescSortOptimization();
 }
diff --git a/server/src/main/java/org/opensearch/search/internal/ShardSearchContextId.java b/server/src/main/java/org/opensearch/search/internal/ShardSearchContextId.java
index e9d1279915f95..b213d06a24e1b 100644
--- a/server/src/main/java/org/opensearch/search/internal/ShardSearchContextId.java
+++ b/server/src/main/java/org/opensearch/search/internal/ShardSearchContextId.java
@@ -33,13 +33,18 @@
 package org.opensearch.search.internal;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Used to support Point in Time Searching
+ *
+ * @opensearch.internal
+ */
 public final class ShardSearchContextId implements Writeable {
     private final String sessionId;
     private final long id;
diff --git a/server/src/main/java/org/opensearch/search/internal/ShardSearchRequest.java b/server/src/main/java/org/opensearch/search/internal/ShardSearchRequest.java
index f41f7fae8b786..017a02e165537 100644
--- a/server/src/main/java/org/opensearch/search/internal/ShardSearchRequest.java
+++ b/server/src/main/java/org/opensearch/search/internal/ShardSearchRequest.java
@@ -44,21 +44,22 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.Rewriteable;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.AliasFilterParsingException;
 import org.opensearch.indices.InvalidAliasNameException;
 import org.opensearch.search.Scroll;
@@ -67,11 +68,11 @@
 import org.opensearch.search.query.QuerySearchResult;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 
@@ -81,8 +82,12 @@
  * Shard level request that represents a search.
  * It provides all the methods that the {@link SearchContext} needs.
  * Provides a cache key based on its content that can be used to cache shard level response.
+ *
+ * @opensearch.internal
  */
 public class ShardSearchRequest extends TransportRequest implements IndicesRequest {
+    public static final ToXContent.Params FORMAT_PARAMS = new ToXContent.MapParams(Collections.singletonMap("pretty", "false"));
+
     private final String clusterAlias;
     private final ShardId shardId;
     private final int numberOfShards;
@@ -499,7 +504,7 @@ public String getClusterAlias() {
 
     @Override
     public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
-        return new SearchShardTask(id, type, action, getDescription(), parentTaskId, headers);
+        return new SearchShardTask(id, type, action, getDescription(), parentTaskId, headers, this::getMetadataSupplier);
     }
 
     @Override
@@ -508,6 +513,16 @@ public String getDescription() {
         return "shardId[" + shardId() + "]";
     }
 
+    public String getMetadataSupplier() {
+        StringBuilder sb = new StringBuilder();
+        if (source != null) {
+            sb.append("source[").append(source.toString(FORMAT_PARAMS)).append("]");
+        } else {
+            sb.append("source[]");
+        }
+        return sb.toString();
+    }
+
     public Rewriteable<Rewriteable> getRewriteable() {
         return new RequestRewritable(this);
     }
@@ -568,7 +583,7 @@ public static QueryBuilder parseAliasFilter(
             return null;
         }
         Index index = metadata.getIndex();
-        ImmutableOpenMap<String, AliasMetadata> aliases = metadata.getAliases();
+        final Map<String, AliasMetadata> aliases = metadata.getAliases();
         Function<AliasMetadata, QueryBuilder> parserFunction = (alias) -> {
             if (alias.filter() == null) {
                 return null;
diff --git a/server/src/main/java/org/opensearch/search/internal/SubSearchContext.java b/server/src/main/java/org/opensearch/search/internal/SubSearchContext.java
index 842c6a514f112..55315013ea8c9 100644
--- a/server/src/main/java/org/opensearch/search/internal/SubSearchContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/SubSearchContext.java
@@ -49,6 +49,11 @@
 
 import java.util.List;
 
+/**
+ * Context for a sub search phase
+ *
+ * @opensearch.internal
+ */
 public class SubSearchContext extends FilteredSearchContext {
 
     // By default return 3 hits per bucket. A higher default would make the response really large by default, since
diff --git a/server/src/main/java/org/opensearch/search/internal/package-info.java b/server/src/main/java/org/opensearch/search/internal/package-info.java
new file mode 100644
index 0000000000000..fb49927753d9c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/internal/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Search Internals package. */
+package org.opensearch.search.internal;
diff --git a/server/src/main/java/org/opensearch/search/lookup/DocLookup.java b/server/src/main/java/org/opensearch/search/lookup/DocLookup.java
index 13e86c235db57..069d9dd02ce2b 100644
--- a/server/src/main/java/org/opensearch/search/lookup/DocLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/DocLookup.java
@@ -38,6 +38,11 @@
 
 import java.util.function.Function;
 
+/**
+ * Looks up a document
+ *
+ * @opensearch.internal
+ */
 public class DocLookup {
 
     private final MapperService mapperService;
diff --git a/server/src/main/java/org/opensearch/search/lookup/FieldLookup.java b/server/src/main/java/org/opensearch/search/lookup/FieldLookup.java
index 6d5b60d016212..6219c3bfb9eaf 100644
--- a/server/src/main/java/org/opensearch/search/lookup/FieldLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/FieldLookup.java
@@ -37,6 +37,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Look up a field
+ *
+ * @opensearch.internal
+ */
 public class FieldLookup {
 
     // we can cached fieldType completely per name, since its on an index/shard level (the lookup, and it does not change within the scope
diff --git a/server/src/main/java/org/opensearch/search/lookup/FieldsLookup.java b/server/src/main/java/org/opensearch/search/lookup/FieldsLookup.java
index 9af22c65aba28..fff2f5f4c814e 100644
--- a/server/src/main/java/org/opensearch/search/lookup/FieldsLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/FieldsLookup.java
@@ -34,6 +34,11 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.index.mapper.MapperService;
 
+/**
+ * looks up multiple fields from a leaf reader
+ *
+ * @opensearch.internal
+ */
 public class FieldsLookup {
 
     private final MapperService mapperService;
diff --git a/server/src/main/java/org/opensearch/search/lookup/LeafDocLookup.java b/server/src/main/java/org/opensearch/search/lookup/LeafDocLookup.java
index 82daa94d92146..fe911ed799646 100644
--- a/server/src/main/java/org/opensearch/search/lookup/LeafDocLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/LeafDocLookup.java
@@ -33,7 +33,6 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -48,12 +47,13 @@
 import java.util.Set;
 import java.util.function.Function;
 
+/**
+ * Looks up a doc from a leaf reader
+ *
+ * @opensearch.internal
+ */
 public class LeafDocLookup implements Map<String, ScriptDocValues<?>> {
 
-    private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(LeafDocLookup.class);
-    static final String TYPES_DEPRECATION_KEY = "type-field-doc-lookup";
-    static final String TYPES_DEPRECATION_MESSAGE = "[types removal] Looking up doc types [_type] in scripts is deprecated.";
-
     private final Map<String, ScriptDocValues<?>> localCacheFieldData = new HashMap<>(4);
 
     private final MapperService mapperService;
@@ -78,10 +78,6 @@ public void setDocument(int docId) {
 
     @Override
     public ScriptDocValues<?> get(Object key) {
-        // deprecate _type
-        if ("_type".equals(key)) {
-            DEPRECATION_LOGGER.deprecate(TYPES_DEPRECATION_KEY, TYPES_DEPRECATION_MESSAGE);
-        }
         // assume its a string...
         String fieldName = key.toString();
         ScriptDocValues<?> scriptValues = localCacheFieldData.get(fieldName);
diff --git a/server/src/main/java/org/opensearch/search/lookup/LeafFieldsLookup.java b/server/src/main/java/org/opensearch/search/lookup/LeafFieldsLookup.java
index 14c5dade52c87..47bb8754a5803 100644
--- a/server/src/main/java/org/opensearch/search/lookup/LeafFieldsLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/LeafFieldsLookup.java
@@ -34,10 +34,8 @@
 import org.apache.lucene.index.LeafReader;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.index.fieldvisitor.SingleFieldsVisitor;
-import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.mapper.TypeFieldMapper;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -49,6 +47,11 @@
 
 import static java.util.Collections.singletonMap;
 
+/**
+ * looks up multiple leaf fields
+ *
+ * @opensearch.internal
+ */
 public class LeafFieldsLookup implements Map {
 
     private final MapperService mapperService;
@@ -147,22 +150,12 @@ private FieldLookup loadFieldData(String name) {
             cachedFieldData.put(name, data);
         }
         if (data.fields() == null) {
-            List<Object> values;
-            if (TypeFieldMapper.NAME.equals(data.fieldType().name())) {
-                TypeFieldMapper.emitTypesDeprecationWarning();
-                values = new ArrayList<>(1);
-                final DocumentMapper mapper = mapperService.documentMapper();
-                if (mapper != null) {
-                    values.add(mapper.type());
-                }
-            } else {
-                values = new ArrayList<Object>(2);
-                SingleFieldsVisitor visitor = new SingleFieldsVisitor(data.fieldType(), values);
-                try {
-                    reader.document(docId, visitor);
-                } catch (IOException e) {
-                    throw new OpenSearchParseException("failed to load field [{}]", e, name);
-                }
+            List<Object> values = new ArrayList<>(2);
+            SingleFieldsVisitor visitor = new SingleFieldsVisitor(data.fieldType(), values);
+            try {
+                reader.storedFields().document(docId, visitor);
+            } catch (IOException e) {
+                throw new OpenSearchParseException("failed to load field [{}]", e, name);
             }
             data.fields(singletonMap(data.fieldType().name(), values));
         }
diff --git a/server/src/main/java/org/opensearch/search/lookup/LeafSearchLookup.java b/server/src/main/java/org/opensearch/search/lookup/LeafSearchLookup.java
index 75a4d7c8d167b..1c87f26053060 100644
--- a/server/src/main/java/org/opensearch/search/lookup/LeafSearchLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/LeafSearchLookup.java
@@ -41,6 +41,8 @@
 
 /**
  * Per-segment version of {@link SearchLookup}.
+ *
+ * @opensearch.internal
  */
 public class LeafSearchLookup {
 
diff --git a/server/src/main/java/org/opensearch/search/lookup/LeafTermFrequencyLookup.java b/server/src/main/java/org/opensearch/search/lookup/LeafTermFrequencyLookup.java
new file mode 100644
index 0000000000000..d02313ada1db9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/lookup/LeafTermFrequencyLookup.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.lookup;
+
+import org.apache.lucene.search.IndexSearcher;
+import org.opensearch.index.query.functionscore.TermFrequencyFunction;
+import org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory;
+import org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+
+/**
+ * Looks up term frequency per-segment
+ *
+ * @opensearch.internal
+ */
+public class LeafTermFrequencyLookup {
+
+    private final IndexSearcher indexSearcher;
+    private final LeafSearchLookup leafLookup;
+    private final Map<String, TermFrequencyFunction> termFreqCache;
+
+    public LeafTermFrequencyLookup(IndexSearcher indexSearcher, LeafSearchLookup leafLookup) {
+        this.indexSearcher = indexSearcher;
+        this.leafLookup = leafLookup;
+        this.termFreqCache = new HashMap<>();
+    }
+
+    public Object getTermFrequency(TermFrequencyFunctionName functionName, String field, String val, int docId) throws IOException {
+        TermFrequencyFunction termFrequencyFunction = getOrCreateTermFrequencyFunction(functionName, field, val);
+        return termFrequencyFunction.execute(docId);
+    }
+
+    private TermFrequencyFunction getOrCreateTermFrequencyFunction(TermFrequencyFunctionName functionName, String field, String val)
+        throws IOException {
+        String cacheKey = (val == null)
+            ? String.format(Locale.ROOT, "%s-%s", functionName, field)
+            : String.format(Locale.ROOT, "%s-%s-%s", functionName, field, val);
+
+        if (!termFreqCache.containsKey(cacheKey)) {
+            TermFrequencyFunction termFrequencyFunction = TermFrequencyFunctionFactory.createFunction(
+                functionName,
+                field,
+                val,
+                leafLookup.ctx,
+                indexSearcher
+            );
+            termFreqCache.put(cacheKey, termFrequencyFunction);
+        }
+
+        return termFreqCache.get(cacheKey);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/lookup/SearchLookup.java b/server/src/main/java/org/opensearch/search/lookup/SearchLookup.java
index 11feb3f2f9e57..898d34dc02c01 100644
--- a/server/src/main/java/org/opensearch/search/lookup/SearchLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/SearchLookup.java
@@ -44,6 +44,11 @@
 import java.util.function.BiFunction;
 import java.util.function.Supplier;
 
+/**
+ * Orchestrator class for search phase lookups
+ *
+ * @opensearch.internal
+ */
 public class SearchLookup {
     /**
      * The maximum depth of field dependencies.
diff --git a/server/src/main/java/org/opensearch/search/lookup/SourceLookup.java b/server/src/main/java/org/opensearch/search/lookup/SourceLookup.java
index eea42bae17483..812030acb9561 100644
--- a/server/src/main/java/org/opensearch/search/lookup/SourceLookup.java
+++ b/server/src/main/java/org/opensearch/search/lookup/SourceLookup.java
@@ -36,12 +36,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.lucene.index.SequentialStoredFieldsLeafReader;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.index.fieldvisitor.FieldsVisitor;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 
@@ -54,6 +55,11 @@
 
 import static java.util.Collections.emptyMap;
 
+/**
+ * Orchestrator class for source lookups
+ *
+ * @opensearch.internal
+ */
 public class SourceLookup implements Map {
 
     private LeafReader reader;
@@ -63,13 +69,13 @@ public class SourceLookup implements Map {
 
     private BytesReference sourceAsBytes;
     private Map<String, Object> source;
-    private XContentType sourceContentType;
+    private MediaType sourceContentType;
 
     public Map<String, Object> source() {
         return source;
     }
 
-    public XContentType sourceContentType() {
+    public MediaType sourceContentType() {
         return sourceContentType;
     }
 
@@ -132,9 +138,9 @@ public void setSegmentAndDocument(LeafReaderContext context, int docId) {
                     // So we do a little hack here and pretend we're going to do merges in order to
                     // get better sequential access.
                     SequentialStoredFieldsLeafReader lf = (SequentialStoredFieldsLeafReader) context.reader();
-                    fieldReader = lf.getSequentialStoredFieldsReader()::visitDocument;
+                    fieldReader = lf.getSequentialStoredFieldsReader()::document;
                 } else {
-                    fieldReader = context.reader()::document;
+                    fieldReader = context.reader().storedFields()::document;
                 }
             } catch (IOException e) {
                 throw new UncheckedIOException(e);
@@ -149,7 +155,7 @@ public void setSource(BytesReference source) {
         this.sourceAsBytes = source;
     }
 
-    public void setSourceContentType(XContentType sourceContentType) {
+    public void setSourceContentType(MediaType sourceContentType) {
         this.sourceContentType = sourceContentType;
     }
 
diff --git a/server/src/main/java/org/opensearch/search/lookup/package-info.java b/server/src/main/java/org/opensearch/search/lookup/package-info.java
new file mode 100644
index 0000000000000..c50520ac84b62
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/lookup/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Lookup package for Fields, Docs, Source, and Leaves. */
+package org.opensearch.search.lookup;
diff --git a/server/src/main/java/org/opensearch/search/package-info.java b/server/src/main/java/org/opensearch/search/package-info.java
new file mode 100644
index 0000000000000..ee35b70defbb2
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Search package. */
+package org.opensearch.search;
diff --git a/server/src/main/java/org/opensearch/search/pipeline/AbstractProcessor.java b/server/src/main/java/org/opensearch/search/pipeline/AbstractProcessor.java
new file mode 100644
index 0000000000000..d197051c5952b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/AbstractProcessor.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+/**
+ * Base class for common processor behavior.
+ */
+public abstract class AbstractProcessor implements Processor {
+    private final String tag;
+    private final String description;
+    private final boolean ignoreFailure;
+
+    protected AbstractProcessor(String tag, String description, boolean ignoreFailure) {
+        this.tag = tag;
+        this.description = description;
+        this.ignoreFailure = ignoreFailure;
+    }
+
+    @Override
+    public String getTag() {
+        return tag;
+    }
+
+    @Override
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public boolean isIgnoreFailure() {
+        return ignoreFailure;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/Pipeline.java b/server/src/main/java/org/opensearch/search/pipeline/Pipeline.java
new file mode 100644
index 0000000000000..d4292b85b20a5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/Pipeline.java
@@ -0,0 +1,252 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseResults;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.Nullable;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.search.SearchPhaseResult;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.LongSupplier;
+
+/**
+ * Concrete representation of a search pipeline, holding multiple processors.
+ */
+class Pipeline {
+
+    public static final String REQUEST_PROCESSORS_KEY = "request_processors";
+    public static final String RESPONSE_PROCESSORS_KEY = "response_processors";
+    public static final String PHASE_PROCESSORS_KEY = "phase_results_processors";
+
+    private static final Logger logger = LogManager.getLogger(Pipeline.class);
+
+    private final String id;
+    private final String description;
+    private final Integer version;
+
+    // TODO: Refactor org.opensearch.ingest.CompoundProcessor to implement our generic Processor interface
+    // Then these can be CompoundProcessors instead of lists.
+    private final List<SearchRequestProcessor> searchRequestProcessors;
+    private final List<SearchResponseProcessor> searchResponseProcessors;
+    private final List<SearchPhaseResultsProcessor> searchPhaseResultsProcessors;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private final LongSupplier relativeTimeSupplier;
+
+    Pipeline(
+        String id,
+        @Nullable String description,
+        @Nullable Integer version,
+        List<SearchRequestProcessor> requestProcessors,
+        List<SearchResponseProcessor> responseProcessors,
+        List<SearchPhaseResultsProcessor> phaseResultsProcessors,
+        NamedWriteableRegistry namedWriteableRegistry,
+        LongSupplier relativeTimeSupplier
+    ) {
+        this.id = id;
+        this.description = description;
+        this.version = version;
+        this.searchRequestProcessors = Collections.unmodifiableList(requestProcessors);
+        this.searchResponseProcessors = Collections.unmodifiableList(responseProcessors);
+        this.searchPhaseResultsProcessors = Collections.unmodifiableList(phaseResultsProcessors);
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        this.relativeTimeSupplier = relativeTimeSupplier;
+    }
+
+    String getId() {
+        return id;
+    }
+
+    String getDescription() {
+        return description;
+    }
+
+    Integer getVersion() {
+        return version;
+    }
+
+    List<SearchRequestProcessor> getSearchRequestProcessors() {
+        return searchRequestProcessors;
+    }
+
+    List<SearchResponseProcessor> getSearchResponseProcessors() {
+        return searchResponseProcessors;
+    }
+
+    List<SearchPhaseResultsProcessor> getSearchPhaseResultsProcessors() {
+        return searchPhaseResultsProcessors;
+    }
+
+    protected void beforeTransformRequest() {}
+
+    protected void afterTransformRequest(long timeInNanos) {}
+
+    protected void onTransformRequestFailure() {}
+
+    protected void beforeRequestProcessor(Processor processor) {}
+
+    protected void afterRequestProcessor(Processor processor, long timeInNanos) {}
+
+    protected void onRequestProcessorFailed(Processor processor) {}
+
+    protected void beforeTransformResponse() {}
+
+    protected void afterTransformResponse(long timeInNanos) {}
+
+    protected void onTransformResponseFailure() {}
+
+    protected void beforeResponseProcessor(Processor processor) {}
+
+    protected void afterResponseProcessor(Processor processor, long timeInNanos) {}
+
+    protected void onResponseProcessorFailed(Processor processor) {}
+
+    SearchRequest transformRequest(SearchRequest request) throws SearchPipelineProcessingException {
+        if (searchRequestProcessors.isEmpty() == false) {
+            long pipelineStart = relativeTimeSupplier.getAsLong();
+            beforeTransformRequest();
+            try {
+                try (BytesStreamOutput bytesStreamOutput = new BytesStreamOutput()) {
+                    request.writeTo(bytesStreamOutput);
+                    try (StreamInput in = bytesStreamOutput.bytes().streamInput()) {
+                        try (StreamInput input = new NamedWriteableAwareStreamInput(in, namedWriteableRegistry)) {
+                            request = new SearchRequest(input);
+                        }
+                    }
+                }
+                for (SearchRequestProcessor processor : searchRequestProcessors) {
+                    beforeRequestProcessor(processor);
+                    long start = relativeTimeSupplier.getAsLong();
+                    try {
+                        request = processor.processRequest(request);
+                    } catch (Exception e) {
+                        onRequestProcessorFailed(processor);
+                        if (processor.isIgnoreFailure()) {
+                            logger.warn(
+                                "The exception from request processor ["
+                                    + processor.getType()
+                                    + "] in the search pipeline ["
+                                    + id
+                                    + "] was ignored",
+                                e
+                            );
+                        } else {
+                            throw e;
+                        }
+                    } finally {
+                        long took = TimeUnit.NANOSECONDS.toMillis(relativeTimeSupplier.getAsLong() - start);
+                        afterRequestProcessor(processor, took);
+                    }
+                }
+            } catch (Exception e) {
+                onTransformRequestFailure();
+                throw new SearchPipelineProcessingException(e);
+            } finally {
+                long took = TimeUnit.NANOSECONDS.toMillis(relativeTimeSupplier.getAsLong() - pipelineStart);
+                afterTransformRequest(took);
+            }
+        }
+        return request;
+    }
+
+    SearchResponse transformResponse(SearchRequest request, SearchResponse response) throws SearchPipelineProcessingException {
+        if (searchResponseProcessors.isEmpty() == false) {
+            long pipelineStart = relativeTimeSupplier.getAsLong();
+            beforeTransformResponse();
+            try {
+                for (SearchResponseProcessor processor : searchResponseProcessors) {
+                    beforeResponseProcessor(processor);
+                    long start = relativeTimeSupplier.getAsLong();
+                    try {
+                        response = processor.processResponse(request, response);
+                    } catch (Exception e) {
+                        onResponseProcessorFailed(processor);
+                        if (processor.isIgnoreFailure()) {
+                            logger.warn(
+                                "The exception from response processor ["
+                                    + processor.getType()
+                                    + "] in the search pipeline ["
+                                    + id
+                                    + "] was ignored",
+                                e
+                            );
+                        } else {
+                            throw e;
+                        }
+                    } finally {
+                        long took = TimeUnit.NANOSECONDS.toMillis(relativeTimeSupplier.getAsLong() - start);
+                        afterResponseProcessor(processor, took);
+                    }
+                }
+            } catch (Exception e) {
+                onTransformResponseFailure();
+                throw new SearchPipelineProcessingException(e);
+            } finally {
+                long took = TimeUnit.NANOSECONDS.toMillis(relativeTimeSupplier.getAsLong() - pipelineStart);
+                afterTransformResponse(took);
+            }
+        }
+        return response;
+    }
+
+    <Result extends SearchPhaseResult> void runSearchPhaseResultsTransformer(
+        SearchPhaseResults<Result> searchPhaseResult,
+        SearchPhaseContext context,
+        String currentPhase,
+        String nextPhase
+    ) throws SearchPipelineProcessingException {
+        try {
+            for (SearchPhaseResultsProcessor searchPhaseResultsProcessor : searchPhaseResultsProcessors) {
+                if (currentPhase.equals(searchPhaseResultsProcessor.getBeforePhase().getName())
+                    && nextPhase.equals(searchPhaseResultsProcessor.getAfterPhase().getName())) {
+                    try {
+                        searchPhaseResultsProcessor.process(searchPhaseResult, context);
+                    } catch (Exception e) {
+                        if (searchPhaseResultsProcessor.isIgnoreFailure()) {
+                            logger.warn(
+                                "The exception from search phase results processor ["
+                                    + searchPhaseResultsProcessor.getType()
+                                    + "] in the search pipeline ["
+                                    + id
+                                    + "] was ignored",
+                                e
+                            );
+                        } else {
+                            throw e;
+                        }
+                    }
+
+                }
+            }
+        } catch (RuntimeException e) {
+            throw new SearchPipelineProcessingException(e);
+        }
+    }
+
+    static final Pipeline NO_OP_PIPELINE = new Pipeline(
+        SearchPipelineService.NOOP_PIPELINE_ID,
+        "Pipeline that does not transform anything",
+        0,
+        Collections.emptyList(),
+        Collections.emptyList(),
+        Collections.emptyList(),
+        null,
+        () -> 0L
+    );
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java b/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java
new file mode 100644
index 0000000000000..9e5f2fa1592a4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java
@@ -0,0 +1,166 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.AbstractDiffable;
+import org.opensearch.cluster.Diff;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * TODO: Copied verbatim from {@link org.opensearch.ingest.PipelineConfiguration}.
+ *
+ * See if we can refactor into a common class. I suspect not, just because this one will hold
+ */
+public class PipelineConfiguration extends AbstractDiffable<PipelineConfiguration> implements ToXContentObject {
+    private static final ObjectParser<Builder, Void> PARSER = new ObjectParser<>(
+        "pipeline_config",
+        true,
+        PipelineConfiguration.Builder::new
+    );
+    static {
+        PARSER.declareString(PipelineConfiguration.Builder::setId, new ParseField("id"));
+        PARSER.declareField((parser, builder, aVoid) -> {
+            XContentBuilder contentBuilder = XContentBuilder.builder(parser.contentType().xContent());
+            contentBuilder.generator().copyCurrentStructure(parser);
+            builder.setConfig(BytesReference.bytes(contentBuilder), contentBuilder.contentType());
+        }, new ParseField("config"), ObjectParser.ValueType.OBJECT);
+
+    }
+
+    public static ContextParser<Void, PipelineConfiguration> getParser() {
+        return (parser, context) -> PARSER.apply(parser, null).build();
+    }
+
+    private static class Builder {
+
+        private String id;
+        private BytesReference config;
+        private MediaType mediaType;
+
+        void setId(String id) {
+            this.id = id;
+        }
+
+        void setConfig(BytesReference config, MediaType mediaType) {
+            if (mediaType instanceof XContentType == false) {
+                throw new IllegalArgumentException("PipelineConfiguration does not support media type [" + mediaType.getClass() + "]");
+            }
+            this.config = config;
+            this.mediaType = mediaType;
+        }
+
+        PipelineConfiguration build() {
+            return new PipelineConfiguration(id, config, mediaType);
+        }
+    }
+
+    private final String id;
+    // Store config as bytes reference, because the config is only used when the pipeline store reads the cluster state
+    // and the way the map of maps config is read requires a deep copy (it removes instead of gets entries to check for unused options)
+    // also the get pipeline api just directly returns this to the caller
+    private final BytesReference config;
+    private final MediaType mediaType;
+
+    public PipelineConfiguration(String id, BytesReference config, MediaType mediaType) {
+        this.id = Objects.requireNonNull(id);
+        this.config = Objects.requireNonNull(config);
+        this.mediaType = Objects.requireNonNull(mediaType);
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public Map<String, Object> getConfigAsMap() {
+        return XContentHelper.convertToMap(config, true, mediaType).v2();
+    }
+
+    // pkg-private for tests
+    MediaType getMediaType() {
+        return mediaType;
+    }
+
+    // pkg-private for tests
+    BytesReference getConfig() {
+        return config;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("id", id);
+        builder.field("config", getConfigAsMap());
+        builder.endObject();
+        return builder;
+    }
+
+    public static PipelineConfiguration readFrom(StreamInput in) throws IOException {
+        return new PipelineConfiguration(
+            in.readString(),
+            in.readBytesReference(),
+            in.getVersion().onOrAfter(Version.V_2_10_0) ? in.readMediaType() : in.readEnum(XContentType.class)
+        );
+    }
+
+    public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IOException {
+        return readDiffFrom(PipelineConfiguration::readFrom, in);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(MediaTypeRegistry.JSON, this);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(id);
+        out.writeBytesReference(config);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        PipelineConfiguration that = (PipelineConfiguration) o;
+
+        if (!id.equals(that.id)) return false;
+        return getConfigAsMap().equals(that.getConfigAsMap());
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id.hashCode();
+        result = 31 * result + getConfigAsMap().hashCode();
+        return result;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/PipelineWithMetrics.java b/server/src/main/java/org/opensearch/search/pipeline/PipelineWithMetrics.java
new file mode 100644
index 0000000000000..827941a8ea81d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/PipelineWithMetrics.java
@@ -0,0 +1,276 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.common.metrics.OperationMetrics;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.ingest.ConfigurationUtils;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.LongSupplier;
+
+import static org.opensearch.ingest.ConfigurationUtils.IGNORE_FAILURE_KEY;
+import static org.opensearch.ingest.ConfigurationUtils.TAG_KEY;
+import static org.opensearch.ingest.Pipeline.DESCRIPTION_KEY;
+import static org.opensearch.ingest.Pipeline.VERSION_KEY;
+
+/**
+ * Specialization of {@link Pipeline} that adds metrics to track executions of the pipeline and individual processors.
+ */
+class PipelineWithMetrics extends Pipeline {
+
+    private final OperationMetrics totalRequestMetrics;
+    private final OperationMetrics totalResponseMetrics;
+    private final OperationMetrics pipelineRequestMetrics = new OperationMetrics();
+    private final OperationMetrics pipelineResponseMetrics = new OperationMetrics();
+    private final Map<String, OperationMetrics> requestProcessorMetrics = new HashMap<>();
+    private final Map<String, OperationMetrics> responseProcessorMetrics = new HashMap<>();
+
+    PipelineWithMetrics(
+        String id,
+        String description,
+        Integer version,
+        List<SearchRequestProcessor> requestProcessors,
+        List<SearchResponseProcessor> responseProcessors,
+        List<SearchPhaseResultsProcessor> phaseResultsProcessors,
+        NamedWriteableRegistry namedWriteableRegistry,
+        OperationMetrics totalRequestMetrics,
+        OperationMetrics totalResponseMetrics,
+        LongSupplier relativeTimeSupplier
+    ) {
+        super(
+            id,
+            description,
+            version,
+            requestProcessors,
+            responseProcessors,
+            phaseResultsProcessors,
+            namedWriteableRegistry,
+            relativeTimeSupplier
+        );
+        this.totalRequestMetrics = totalRequestMetrics;
+        this.totalResponseMetrics = totalResponseMetrics;
+        for (Processor requestProcessor : getSearchRequestProcessors()) {
+            requestProcessorMetrics.putIfAbsent(getProcessorKey(requestProcessor), new OperationMetrics());
+        }
+        for (Processor responseProcessor : getSearchResponseProcessors()) {
+            responseProcessorMetrics.putIfAbsent(getProcessorKey(responseProcessor), new OperationMetrics());
+        }
+    }
+
+    static PipelineWithMetrics create(
+        String id,
+        Map<String, Object> config,
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorFactories,
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessorFactories,
+        Map<String, Processor.Factory<SearchPhaseResultsProcessor>> phaseResultsProcessorFactories,
+        NamedWriteableRegistry namedWriteableRegistry,
+        OperationMetrics totalRequestProcessingMetrics,
+        OperationMetrics totalResponseProcessingMetrics,
+        Processor.PipelineContext pipelineContext
+    ) throws Exception {
+        String description = ConfigurationUtils.readOptionalStringProperty(null, null, config, DESCRIPTION_KEY);
+        Integer version = ConfigurationUtils.readIntProperty(null, null, config, VERSION_KEY, null);
+        List<Map<String, Object>> requestProcessorConfigs = ConfigurationUtils.readOptionalList(null, null, config, REQUEST_PROCESSORS_KEY);
+        List<SearchRequestProcessor> requestProcessors = readProcessors(
+            requestProcessorFactories,
+            requestProcessorConfigs,
+            pipelineContext
+        );
+        List<Map<String, Object>> responseProcessorConfigs = ConfigurationUtils.readOptionalList(
+            null,
+            null,
+            config,
+            RESPONSE_PROCESSORS_KEY
+        );
+        List<SearchResponseProcessor> responseProcessors = readProcessors(
+            responseProcessorFactories,
+            responseProcessorConfigs,
+            pipelineContext
+        );
+        List<Map<String, Object>> phaseResultsProcessorConfigs = ConfigurationUtils.readOptionalList(
+            null,
+            null,
+            config,
+            PHASE_PROCESSORS_KEY
+        );
+        List<SearchPhaseResultsProcessor> phaseResultsProcessors = readProcessors(
+            phaseResultsProcessorFactories,
+            phaseResultsProcessorConfigs,
+            pipelineContext
+        );
+        if (config.isEmpty() == false) {
+            throw new OpenSearchParseException(
+                "pipeline ["
+                    + id
+                    + "] doesn't support one or more provided configuration parameters "
+                    + Arrays.toString(config.keySet().toArray())
+            );
+        }
+        return new PipelineWithMetrics(
+            id,
+            description,
+            version,
+            requestProcessors,
+            responseProcessors,
+            phaseResultsProcessors,
+            namedWriteableRegistry,
+            totalRequestProcessingMetrics,
+            totalResponseProcessingMetrics,
+            System::nanoTime
+        );
+
+    }
+
+    private static <T extends Processor> List<T> readProcessors(
+        Map<String, Processor.Factory<T>> processorFactories,
+        List<Map<String, Object>> requestProcessorConfigs,
+        Processor.PipelineContext pipelineContext
+    ) throws Exception {
+        List<T> processors = new ArrayList<>();
+        if (requestProcessorConfigs == null) {
+            return processors;
+        }
+        for (Map<String, Object> processorConfigWithKey : requestProcessorConfigs) {
+            for (Map.Entry<String, Object> entry : processorConfigWithKey.entrySet()) {
+                String type = entry.getKey();
+                if (!processorFactories.containsKey(type)) {
+                    throw new IllegalArgumentException("Invalid processor type " + type);
+                }
+                Map<String, Object> config = (Map<String, Object>) entry.getValue();
+                String tag = ConfigurationUtils.readOptionalStringProperty(null, null, config, TAG_KEY);
+                boolean ignoreFailure = ConfigurationUtils.readBooleanProperty(null, null, config, IGNORE_FAILURE_KEY, false);
+                String description = ConfigurationUtils.readOptionalStringProperty(null, tag, config, DESCRIPTION_KEY);
+                processors.add(
+                    processorFactories.get(type).create(processorFactories, tag, description, ignoreFailure, config, pipelineContext)
+                );
+                if (config.isEmpty() == false) {
+                    String processorName = type;
+                    if (tag != null) {
+                        processorName = processorName + ":" + tag;
+                    }
+                    throw new OpenSearchParseException(
+                        "processor ["
+                            + processorName
+                            + "] doesn't support one or more provided configuration parameters: "
+                            + Arrays.toString(config.keySet().toArray())
+                    );
+                }
+            }
+        }
+        return Collections.unmodifiableList(processors);
+    }
+
+    @Override
+    protected void beforeTransformRequest() {
+        super.beforeTransformRequest();
+        totalRequestMetrics.before();
+        pipelineRequestMetrics.before();
+    }
+
+    @Override
+    protected void afterTransformRequest(long timeInNanos) {
+        super.afterTransformRequest(timeInNanos);
+        totalRequestMetrics.after(timeInNanos);
+        pipelineRequestMetrics.after(timeInNanos);
+    }
+
+    @Override
+    protected void onTransformRequestFailure() {
+        super.onTransformRequestFailure();
+        totalRequestMetrics.failed();
+        pipelineRequestMetrics.failed();
+    }
+
+    protected void beforeRequestProcessor(Processor processor) {
+        requestProcessorMetrics.get(getProcessorKey(processor)).before();
+    }
+
+    protected void afterRequestProcessor(Processor processor, long timeInNanos) {
+        requestProcessorMetrics.get(getProcessorKey(processor)).after(timeInNanos);
+    }
+
+    protected void onRequestProcessorFailed(Processor processor) {
+        requestProcessorMetrics.get(getProcessorKey(processor)).failed();
+    }
+
+    protected void beforeTransformResponse() {
+        super.beforeTransformRequest();
+        totalResponseMetrics.before();
+        pipelineResponseMetrics.before();
+    }
+
+    protected void afterTransformResponse(long timeInNanos) {
+        super.afterTransformResponse(timeInNanos);
+        totalResponseMetrics.after(timeInNanos);
+        pipelineResponseMetrics.after(timeInNanos);
+    }
+
+    protected void onTransformResponseFailure() {
+        super.onTransformResponseFailure();
+        totalResponseMetrics.failed();
+        pipelineResponseMetrics.failed();
+    }
+
+    protected void beforeResponseProcessor(Processor processor) {
+        responseProcessorMetrics.get(getProcessorKey(processor)).before();
+    }
+
+    protected void afterResponseProcessor(Processor processor, long timeInNanos) {
+        responseProcessorMetrics.get(getProcessorKey(processor)).after(timeInNanos);
+    }
+
+    protected void onResponseProcessorFailed(Processor processor) {
+        responseProcessorMetrics.get(getProcessorKey(processor)).failed();
+    }
+
+    void copyMetrics(PipelineWithMetrics oldPipeline) {
+        pipelineRequestMetrics.add(oldPipeline.pipelineRequestMetrics);
+        pipelineResponseMetrics.add(oldPipeline.pipelineResponseMetrics);
+        copyProcessorMetrics(requestProcessorMetrics, oldPipeline.requestProcessorMetrics);
+        copyProcessorMetrics(responseProcessorMetrics, oldPipeline.responseProcessorMetrics);
+    }
+
+    private static <T extends Processor> void copyProcessorMetrics(
+        Map<String, OperationMetrics> newProcessorMetrics,
+        Map<String, OperationMetrics> oldProcessorMetrics
+    ) {
+        for (Map.Entry<String, OperationMetrics> oldProcessorMetric : oldProcessorMetrics.entrySet()) {
+            if (newProcessorMetrics.containsKey(oldProcessorMetric.getKey())) {
+                newProcessorMetrics.get(oldProcessorMetric.getKey()).add(oldProcessorMetric.getValue());
+            }
+        }
+    }
+
+    private static String getProcessorKey(Processor processor) {
+        String key = processor.getType();
+        if (processor.getTag() != null) {
+            return key + ":" + processor.getTag();
+        }
+        return key;
+    }
+
+    void populateStats(SearchPipelineStats.Builder statsBuilder) {
+        statsBuilder.addPipelineStats(getId(), pipelineRequestMetrics, pipelineResponseMetrics);
+        for (Processor processor : getSearchRequestProcessors()) {
+            String key = getProcessorKey(processor);
+            statsBuilder.addRequestProcessorStats(getId(), key, processor.getType(), requestProcessorMetrics.get(key));
+        }
+        for (Processor processor : getSearchResponseProcessors()) {
+            String key = getProcessorKey(processor);
+            statsBuilder.addResponseProcessorStats(getId(), key, processor.getType(), responseProcessorMetrics.get(key));
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/PipelinedRequest.java b/server/src/main/java/org/opensearch/search/pipeline/PipelinedRequest.java
new file mode 100644
index 0000000000000..5a7539808c127
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/PipelinedRequest.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseResults;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.search.SearchPhaseResult;
+
+/**
+ * Groups a search pipeline based on a request and the request after being transformed by the pipeline.
+ *
+ * @opensearch.internal
+ */
+public final class PipelinedRequest extends SearchRequest {
+    private final Pipeline pipeline;
+
+    PipelinedRequest(Pipeline pipeline, SearchRequest transformedRequest) {
+        super(transformedRequest);
+        this.pipeline = pipeline;
+    }
+
+    public SearchResponse transformResponse(SearchResponse response) {
+        return pipeline.transformResponse(this, response);
+    }
+
+    public <Result extends SearchPhaseResult> void transformSearchPhaseResults(
+        final SearchPhaseResults<Result> searchPhaseResult,
+        final SearchPhaseContext searchPhaseContext,
+        final String currentPhase,
+        final String nextPhase
+    ) {
+        pipeline.runSearchPhaseResultsTransformer(searchPhaseResult, searchPhaseContext, currentPhase, nextPhase);
+    }
+
+    // Visible for testing
+    Pipeline getPipeline() {
+        return pipeline;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/Processor.java b/server/src/main/java/org/opensearch/search/pipeline/Processor.java
new file mode 100644
index 0000000000000..fb33f46acada4
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/Processor.java
@@ -0,0 +1,105 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import java.util.Map;
+
+/**
+ * A processor implementation may modify the request or response from a search call.
+ * Whether changes are made and what exactly is modified is up to the implementation.
+ * <p>
+ * Processors may get called concurrently and thus need to be thread-safe.
+ *
+ * TODO: Refactor {@link org.opensearch.ingest.Processor} to extend this interface, and specialize to IngestProcessor.
+ *
+ * @opensearch.internal
+ */
+public interface Processor {
+    /**
+     * Processor configuration key to let the factory know the context for pipeline creation.
+     * <p>
+     * See {@link PipelineSource}.
+     */
+    String PIPELINE_SOURCE = "pipeline_source";
+
+    /**
+     * Gets the type of processor
+     */
+    String getType();
+
+    /**
+     * Gets the tag of a processor.
+     */
+    String getTag();
+
+    /**
+     * Gets the description of a processor.
+     */
+    String getDescription();
+
+    /**
+     * Gets the setting of ignoreFailure of a processor.
+     */
+    boolean isIgnoreFailure();
+
+    /**
+     * A factory that knows how to construct a processor based on a map of maps.
+     */
+    interface Factory<T extends Processor> {
+
+        /**
+         * Creates a processor based on the specified map of maps config.
+         *
+         * @param processorFactories Other processors which may be created inside this processor
+         * @param tag                The tag for the processor
+         * @param description        A short description of what this processor does
+         * @param config             The configuration for the processor
+         *                           <b>Note:</b> Implementations are responsible for removing the used configuration
+         *                           keys, so that after creation the config map should be empty.
+         * @param pipelineContext    Contextual information about the enclosing pipeline.
+         */
+        T create(
+            Map<String, Factory<T>> processorFactories,
+            String tag,
+            String description,
+            boolean ignoreFailure,
+            Map<String, Object> config,
+            PipelineContext pipelineContext
+        ) throws Exception;
+    }
+
+    /**
+     * Contextual information about the enclosing pipeline. A processor factory may change processor initialization behavior or
+     * pass this information to the created processor instance.
+     */
+    class PipelineContext {
+        private final PipelineSource pipelineSource;
+
+        public PipelineContext(PipelineSource pipelineSource) {
+            this.pipelineSource = pipelineSource;
+        }
+
+        public PipelineSource getPipelineSource() {
+            return pipelineSource;
+        }
+    }
+
+    /**
+     * A processor factory may change the processor initialization behavior based on the creation context (e.g. avoiding
+     * creating expensive resources during validation or in a request-scoped pipeline.)
+     */
+    enum PipelineSource {
+        // A named pipeline is being created or updated
+        UPDATE_PIPELINE,
+        // Pipeline is defined within a search request
+        SEARCH_REQUEST,
+        // A named pipeline is being validated before being written to cluster state
+        VALIDATE_PIPELINE
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/ProcessorInfo.java b/server/src/main/java/org/opensearch/search/pipeline/ProcessorInfo.java
new file mode 100644
index 0000000000000..0206b9b6cf716
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/ProcessorInfo.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Information about a search pipeline  processor
+ *
+ * TODO: This is copy/pasted from the ingest ProcessorInfo.
+ * Can/should we share implementation or is this just boilerplate?
+ *
+ * @opensearch.internal
+ */
+public class ProcessorInfo implements Writeable, ToXContentObject, Comparable<ProcessorInfo> {
+
+    private final String type;
+
+    public ProcessorInfo(String type) {
+        this.type = type;
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public ProcessorInfo(StreamInput input) throws IOException {
+        type = input.readString();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(this.type);
+    }
+
+    /**
+     * @return The unique processor type
+     */
+    public String getType() {
+        return type;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("type", type);
+        builder.endObject();
+        return null;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        ProcessorInfo that = (ProcessorInfo) o;
+
+        return type.equals(that.type);
+
+    }
+
+    @Override
+    public int hashCode() {
+        return type.hashCode();
+    }
+
+    @Override
+    public int compareTo(ProcessorInfo o) {
+        return type.compareTo(o.type);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPhaseResultsProcessor.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPhaseResultsProcessor.java
new file mode 100644
index 0000000000000..772dc8758bace
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPhaseResultsProcessor.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchPhaseResults;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.internal.SearchContext;
+
+/**
+ * Creates a processor that runs between Phases of the Search.
+ * @opensearch.api
+ */
+public interface SearchPhaseResultsProcessor extends Processor {
+
+    /**
+     * Processes the {@link SearchPhaseResults} obtained from a SearchPhase which will be returned to next
+     * SearchPhase.
+     * @param searchPhaseResult {@link SearchPhaseResults}
+     * @param searchPhaseContext {@link SearchContext}
+     * @param <Result> {@link SearchPhaseResult}
+     */
+    <Result extends SearchPhaseResult> void process(
+        final SearchPhaseResults<Result> searchPhaseResult,
+        final SearchPhaseContext searchPhaseContext
+    );
+
+    /**
+     * The phase which should have run before, this processor can start executing.
+     * @return {@link SearchPhaseName}
+     */
+    SearchPhaseName getBeforePhase();
+
+    /**
+     * The phase which should run after, this processor execution.
+     * @return {@link SearchPhaseName}
+     */
+    SearchPhaseName getAfterPhase();
+
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineInfo.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineInfo.java
new file mode 100644
index 0000000000000..c60638e80ddbe
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineInfo.java
@@ -0,0 +1,123 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.Version;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+/**
+ * Information about a search pipelines event
+ *
+ * @opensearch.internal
+ */
+public class SearchPipelineInfo implements ReportingService.Info {
+
+    private final Map<String, Set<ProcessorInfo>> processors = new TreeMap<>();
+
+    public SearchPipelineInfo(Map<String, List<ProcessorInfo>> processors) {
+        for (Map.Entry<String, List<ProcessorInfo>> processorsEntry : processors.entrySet()) {
+            // we use a treeset here to have a test-able / predictable order
+            this.processors.put(processorsEntry.getKey(), new TreeSet<>(processorsEntry.getValue()));
+        }
+    }
+
+    /**
+     * Read from a stream.
+     */
+    public SearchPipelineInfo(StreamInput in) throws IOException {
+        if (in.getVersion().before(Version.V_2_8_0)) {
+            // Prior to version 2.8, we had a flat list of processors. For best compatibility, assume they're valid
+            // request and response processor, since we couldn't tell the difference back then.
+            final int size = in.readVInt();
+            Set<ProcessorInfo> processorInfos = new TreeSet<>();
+            for (int i = 0; i < size; i++) {
+                processorInfos.add(new ProcessorInfo(in));
+            }
+            processors.put(Pipeline.REQUEST_PROCESSORS_KEY, processorInfos);
+            processors.put(Pipeline.RESPONSE_PROCESSORS_KEY, processorInfos);
+        } else {
+            final int numTypes = in.readVInt();
+            for (int i = 0; i < numTypes; i++) {
+                String type = in.readString();
+                int numProcessors = in.readVInt();
+                Set<ProcessorInfo> processorInfos = new TreeSet<>();
+                for (int j = 0; j < numProcessors; j++) {
+                    processorInfos.add(new ProcessorInfo(in));
+                }
+                processors.put(type, processorInfos);
+            }
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject("search_pipelines");
+        for (Map.Entry<String, Set<ProcessorInfo>> processorEntry : processors.entrySet()) {
+            builder.startArray(processorEntry.getKey());
+            for (ProcessorInfo info : processorEntry.getValue()) {
+                info.toXContent(builder, params);
+            }
+            builder.endArray();
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        if (out.getVersion().before(Version.V_2_8_0)) {
+            // Prior to version 2.8, we grouped all processors into a single list.
+            Set<ProcessorInfo> processorInfos = new TreeSet<>();
+            processorInfos.addAll(processors.getOrDefault(Pipeline.REQUEST_PROCESSORS_KEY, Collections.emptySet()));
+            processorInfos.addAll(processors.getOrDefault(Pipeline.RESPONSE_PROCESSORS_KEY, Collections.emptySet()));
+            out.writeVInt(processorInfos.size());
+            for (ProcessorInfo processorInfo : processorInfos) {
+                processorInfo.writeTo(out);
+            }
+        } else {
+            out.write(processors.size());
+            for (Map.Entry<String, Set<ProcessorInfo>> processorsEntry : processors.entrySet()) {
+                out.writeString(processorsEntry.getKey());
+                out.writeVInt(processorsEntry.getValue().size());
+                for (ProcessorInfo processorInfo : processorsEntry.getValue()) {
+                    processorInfo.writeTo(out);
+                }
+            }
+        }
+    }
+
+    public boolean containsProcessor(String processorType, String type) {
+        return processors.containsKey(processorType) && processors.get(processorType).contains(new ProcessorInfo(type));
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchPipelineInfo that = (SearchPipelineInfo) o;
+        return Objects.equals(processors, that.processors);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(processors);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineMetadata.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineMetadata.java
new file mode 100644
index 0000000000000..56f8399c22412
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineMetadata.java
@@ -0,0 +1,163 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.Diff;
+import org.opensearch.cluster.DiffableUtils;
+import org.opensearch.cluster.NamedDiff;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Represents the search pipelines that are available in the cluster
+ *
+ * @opensearch.internal
+ */
+public class SearchPipelineMetadata implements Metadata.Custom {
+    public static final String TYPE = "search_pipeline";
+
+    private static final ParseField PIPELINES_FIELD = new ParseField("pipeline");
+    private static final ObjectParser<List<PipelineConfiguration>, Void> SEARCH_PIPELINE_METADATA_PARSER = new ObjectParser<>(
+        "search_pipeline_metadata",
+        ArrayList::new
+    );
+    static {
+        SEARCH_PIPELINE_METADATA_PARSER.declareObjectArray(List::addAll, PipelineConfiguration.getParser(), PIPELINES_FIELD);
+    }
+    // Mapping from pipeline ID to each pipeline's configuration.
+    private final Map<String, PipelineConfiguration> pipelines;
+
+    public SearchPipelineMetadata(Map<String, PipelineConfiguration> pipelines) {
+        this.pipelines = Collections.unmodifiableMap(pipelines);
+    }
+
+    @Override
+    public String getWriteableName() {
+        return TYPE;
+    }
+
+    @Override
+    public Version getMinimalSupportedVersion() {
+        return Version.CURRENT.minimumCompatibilityVersion();
+    }
+
+    public Map<String, PipelineConfiguration> getPipelines() {
+        return pipelines;
+    }
+
+    public SearchPipelineMetadata(StreamInput in) throws IOException {
+        int size = in.readVInt();
+        Map<String, PipelineConfiguration> pipelines = new HashMap<>(size);
+        for (int i = 0; i < size; i++) {
+            PipelineConfiguration pipeline = PipelineConfiguration.readFrom(in);
+            pipelines.put(pipeline.getId(), pipeline);
+        }
+        this.pipelines = Collections.unmodifiableMap(pipelines);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVInt(pipelines.size());
+        for (PipelineConfiguration pipeline : pipelines.values()) {
+            pipeline.writeTo(out);
+        }
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startArray(PIPELINES_FIELD.getPreferredName());
+        for (PipelineConfiguration pipeline : pipelines.values()) {
+            pipeline.toXContent(builder, params);
+        }
+        builder.endArray();
+        return builder;
+    }
+
+    public static SearchPipelineMetadata fromXContent(XContentParser parser) throws IOException {
+        Map<String, PipelineConfiguration> pipelines = new HashMap<>();
+        List<PipelineConfiguration> configs = SEARCH_PIPELINE_METADATA_PARSER.parse(parser, null);
+        for (PipelineConfiguration pipeline : configs) {
+            pipelines.put(pipeline.getId(), pipeline);
+        }
+        return new SearchPipelineMetadata(pipelines);
+    }
+
+    @Override
+    public EnumSet<Metadata.XContentContext> context() {
+        return Metadata.ALL_CONTEXTS;
+    }
+
+    @Override
+    public Diff<Metadata.Custom> diff(Metadata.Custom previousState) {
+        return new SearchPipelineMetadataDiff((SearchPipelineMetadata) previousState, this);
+    }
+
+    public static NamedDiff<Metadata.Custom> readDiffFrom(StreamInput in) throws IOException {
+        return new SearchPipelineMetadataDiff(in);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchPipelineMetadata that = (SearchPipelineMetadata) o;
+        return pipelines.equals(that.pipelines);
+    }
+
+    @Override
+    public int hashCode() {
+        return pipelines.hashCode();
+    }
+
+    static class SearchPipelineMetadataDiff implements NamedDiff<Metadata.Custom> {
+        final Diff<Map<String, PipelineConfiguration>> pipelines;
+
+        public SearchPipelineMetadataDiff(SearchPipelineMetadata before, SearchPipelineMetadata after) {
+            this.pipelines = DiffableUtils.diff(before.pipelines, after.pipelines, DiffableUtils.getStringKeySerializer());
+        }
+
+        public SearchPipelineMetadataDiff(StreamInput in) throws IOException {
+            this.pipelines = DiffableUtils.readJdkMapDiff(
+                in,
+                DiffableUtils.getStringKeySerializer(),
+                PipelineConfiguration::readFrom,
+                PipelineConfiguration::readDiffFrom
+            );
+        }
+
+        @Override
+        public Metadata.Custom apply(Metadata.Custom part) {
+            return new SearchPipelineMetadata(pipelines.apply(((SearchPipelineMetadata) part).pipelines));
+        }
+
+        @Override
+        public String getWriteableName() {
+            return TYPE;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            pipelines.writeTo(out);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineProcessingException.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineProcessingException.java
new file mode 100644
index 0000000000000..5e175a7240fd8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineProcessingException.java
@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.OpenSearchWrapperException;
+import org.opensearch.core.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+/**
+ * A dedicated wrapper for exceptions encountered executing a search pipeline processor. The wrapper is needed as we
+ * currently only unwrap causes for instances of {@link OpenSearchWrapperException}.
+ *
+ * @opensearch.internal
+ */
+public class SearchPipelineProcessingException extends OpenSearchException implements OpenSearchWrapperException {
+    SearchPipelineProcessingException(Exception cause) {
+        super(cause);
+    }
+
+    public SearchPipelineProcessingException(StreamInput in) throws IOException {
+        super(in);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineService.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineService.java
new file mode 100644
index 0000000000000..739101519ff98
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineService.java
@@ -0,0 +1,498 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.ResourceNotFoundException;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.AckedClusterStateUpdateTask;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateApplier;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.metrics.OperationMetrics;
+import org.opensearch.common.regex.Regex;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.gateway.GatewayService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.analysis.AnalysisRegistry;
+import org.opensearch.ingest.ConfigurationUtils;
+import org.opensearch.plugins.SearchPipelinePlugin;
+import org.opensearch.script.ScriptService;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * The main entry point for search pipelines. Handles CRUD operations and exposes the API to execute search pipelines
+ * against requests and responses.
+ */
+public class SearchPipelineService implements ClusterStateApplier, ReportingService<SearchPipelineInfo> {
+
+    public static final String SEARCH_PIPELINE_ORIGIN = "search_pipeline";
+    public static final String AD_HOC_PIPELINE_ID = "_ad_hoc_pipeline";
+    public static final String NOOP_PIPELINE_ID = "_none";
+    private static final Logger logger = LogManager.getLogger(SearchPipelineService.class);
+    private final ClusterService clusterService;
+    private final ScriptService scriptService;
+    private final Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorFactories;
+    private final Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessorFactories;
+    private final Map<String, Processor.Factory<SearchPhaseResultsProcessor>> phaseInjectorProcessorFactories;
+    private volatile Map<String, PipelineHolder> pipelines = Collections.emptyMap();
+    private final ThreadPool threadPool;
+    private final List<Consumer<ClusterState>> searchPipelineClusterStateListeners = new CopyOnWriteArrayList<>();
+    private final ClusterManagerTaskThrottler.ThrottlingKey putPipelineTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deletePipelineTaskKey;
+    private final NamedWriteableRegistry namedWriteableRegistry;
+    private volatile ClusterState state;
+
+    private final OperationMetrics totalRequestProcessingMetrics = new OperationMetrics();
+    private final OperationMetrics totalResponseProcessingMetrics = new OperationMetrics();
+
+    public SearchPipelineService(
+        ClusterService clusterService,
+        ThreadPool threadPool,
+        Environment env,
+        ScriptService scriptService,
+        AnalysisRegistry analysisRegistry,
+        NamedXContentRegistry namedXContentRegistry,
+        NamedWriteableRegistry namedWriteableRegistry,
+        List<SearchPipelinePlugin> searchPipelinePlugins,
+        Client client
+    ) {
+        this.clusterService = clusterService;
+        this.scriptService = scriptService;
+        this.threadPool = threadPool;
+        this.namedWriteableRegistry = namedWriteableRegistry;
+        SearchPipelinePlugin.Parameters parameters = new SearchPipelinePlugin.Parameters(
+            env,
+            scriptService,
+            analysisRegistry,
+            threadPool.getThreadContext(),
+            threadPool::relativeTimeInMillis,
+            (delay, command) -> threadPool.schedule(command, TimeValue.timeValueMillis(delay), ThreadPool.Names.GENERIC),
+            this,
+            client,
+            threadPool.generic()::execute,
+            namedXContentRegistry
+        );
+        this.requestProcessorFactories = processorFactories(searchPipelinePlugins, p -> p.getRequestProcessors(parameters));
+        this.responseProcessorFactories = processorFactories(searchPipelinePlugins, p -> p.getResponseProcessors(parameters));
+        this.phaseInjectorProcessorFactories = processorFactories(
+            searchPipelinePlugins,
+            p -> p.getSearchPhaseResultsProcessors(parameters)
+        );
+        putPipelineTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.PUT_SEARCH_PIPELINE_KEY, true);
+        deletePipelineTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_SEARCH_PIPELINE_KEY, true);
+    }
+
+    private static <T extends Processor> Map<String, Processor.Factory<T>> processorFactories(
+        List<SearchPipelinePlugin> searchPipelinePlugins,
+        Function<SearchPipelinePlugin, Map<String, Processor.Factory<T>>> processorLoader
+    ) {
+        Map<String, Processor.Factory<T>> processorFactories = new HashMap<>();
+        for (SearchPipelinePlugin searchPipelinePlugin : searchPipelinePlugins) {
+            Map<String, Processor.Factory<T>> newProcessors = processorLoader.apply(searchPipelinePlugin);
+            for (Map.Entry<String, Processor.Factory<T>> entry : newProcessors.entrySet()) {
+                if (processorFactories.put(entry.getKey(), entry.getValue()) != null) {
+                    throw new IllegalArgumentException("Search processor [" + entry.getKey() + "] is already registered");
+                }
+            }
+        }
+        return Collections.unmodifiableMap(processorFactories);
+    }
+
+    @Override
+    public void applyClusterState(ClusterChangedEvent event) {
+        state = event.state();
+
+        if (state.blocks().hasGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK)) {
+            return;
+        }
+        searchPipelineClusterStateListeners.forEach(consumer -> consumer.accept(state));
+
+        SearchPipelineMetadata newSearchPipelineMetadata = state.getMetadata().custom(SearchPipelineMetadata.TYPE);
+        if (newSearchPipelineMetadata == null) {
+            return;
+        }
+
+        try {
+            innerUpdatePipelines(newSearchPipelineMetadata);
+        } catch (OpenSearchParseException e) {
+            logger.warn("failed to update search pipelines", e);
+        }
+    }
+
+    void innerUpdatePipelines(SearchPipelineMetadata newSearchPipelineMetadata) {
+        Map<String, PipelineHolder> existingPipelines = this.pipelines;
+
+        // Lazily initialize these variables in order to favour the most likely scenario that there are no pipeline changes:
+        Map<String, PipelineHolder> newPipelines = null;
+        List<OpenSearchParseException> exceptions = null;
+        // Iterate over pipeline configurations in metadata and constructs a new pipeline if there is no pipeline
+        // or the pipeline configuration has been modified
+
+        for (PipelineConfiguration newConfiguration : newSearchPipelineMetadata.getPipelines().values()) {
+            PipelineHolder previous = existingPipelines.get(newConfiguration.getId());
+            if (previous != null && previous.configuration.equals(newConfiguration)) {
+                continue;
+            }
+            if (newPipelines == null) {
+                newPipelines = new HashMap<>(existingPipelines);
+            }
+            try {
+                PipelineWithMetrics newPipeline = PipelineWithMetrics.create(
+                    newConfiguration.getId(),
+                    newConfiguration.getConfigAsMap(),
+                    requestProcessorFactories,
+                    responseProcessorFactories,
+                    phaseInjectorProcessorFactories,
+                    namedWriteableRegistry,
+                    totalRequestProcessingMetrics,
+                    totalResponseProcessingMetrics,
+                    new Processor.PipelineContext(Processor.PipelineSource.UPDATE_PIPELINE)
+                );
+                newPipelines.put(newConfiguration.getId(), new PipelineHolder(newConfiguration, newPipeline));
+
+                if (previous != null) {
+                    newPipeline.copyMetrics(previous.pipeline);
+                }
+            } catch (Exception e) {
+                OpenSearchParseException parseException = new OpenSearchParseException(
+                    "Error updating pipeline with id [" + newConfiguration.getId() + "]",
+                    e
+                );
+                // TODO -- replace pipeline with one that throws this exception when we try to use it
+                if (exceptions == null) {
+                    exceptions = new ArrayList<>();
+                }
+                exceptions.add(parseException);
+            }
+        }
+        // Iterate over the current active pipelines and check whether they are missing in the pipeline configuration and
+        // if so delete the pipeline from new Pipelines map:
+        for (Map.Entry<String, PipelineHolder> entry : existingPipelines.entrySet()) {
+            if (newSearchPipelineMetadata.getPipelines().get(entry.getKey()) == null) {
+                if (newPipelines == null) {
+                    newPipelines = new HashMap<>(existingPipelines);
+                }
+                newPipelines.remove(entry.getKey());
+            }
+        }
+
+        if (newPipelines != null) {
+            this.pipelines = Collections.unmodifiableMap(newPipelines);
+            if (exceptions != null) {
+                ExceptionsHelper.rethrowAndSuppress(exceptions);
+            }
+        }
+    }
+
+    public void putPipeline(
+        Map<DiscoveryNode, SearchPipelineInfo> searchPipelineInfos,
+        PutSearchPipelineRequest request,
+        ActionListener<AcknowledgedResponse> listener
+    ) throws Exception {
+        validatePipeline(searchPipelineInfos, request);
+        clusterService.submitStateUpdateTask(
+            "put-search-pipeline-" + request.getId(),
+            new AckedClusterStateUpdateTask<>(request, listener) {
+                @Override
+                public ClusterState execute(ClusterState currentState) {
+                    return innerPut(request, currentState);
+                }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return putPipelineTaskKey;
+                }
+
+                @Override
+                protected AcknowledgedResponse newResponse(boolean acknowledged) {
+                    return new AcknowledgedResponse(acknowledged);
+                }
+            }
+        );
+    }
+
+    static ClusterState innerPut(PutSearchPipelineRequest request, ClusterState currentState) {
+        SearchPipelineMetadata currentSearchPipelineMetadata = currentState.metadata().custom(SearchPipelineMetadata.TYPE);
+        Map<String, PipelineConfiguration> pipelines;
+        if (currentSearchPipelineMetadata != null) {
+            pipelines = new HashMap<>(currentSearchPipelineMetadata.getPipelines());
+        } else {
+            pipelines = new HashMap<>();
+        }
+        pipelines.put(request.getId(), new PipelineConfiguration(request.getId(), request.getSource(), request.getMediaType()));
+        ClusterState.Builder newState = ClusterState.builder(currentState);
+        newState.metadata(
+            Metadata.builder(currentState.getMetadata())
+                .putCustom(SearchPipelineMetadata.TYPE, new SearchPipelineMetadata(pipelines))
+                .build()
+        );
+        return newState.build();
+    }
+
+    void validatePipeline(Map<DiscoveryNode, SearchPipelineInfo> searchPipelineInfos, PutSearchPipelineRequest request) throws Exception {
+        if (searchPipelineInfos.isEmpty()) {
+            throw new IllegalStateException("Search pipeline info is empty");
+        }
+        Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getMediaType()).v2();
+        Pipeline pipeline = PipelineWithMetrics.create(
+            request.getId(),
+            pipelineConfig,
+            requestProcessorFactories,
+            responseProcessorFactories,
+            phaseInjectorProcessorFactories,
+            namedWriteableRegistry,
+            new OperationMetrics(), // Use ephemeral metrics for validation
+            new OperationMetrics(),
+            new Processor.PipelineContext(Processor.PipelineSource.VALIDATE_PIPELINE)
+        );
+        List<Exception> exceptions = new ArrayList<>();
+        for (SearchRequestProcessor processor : pipeline.getSearchRequestProcessors()) {
+            for (Map.Entry<DiscoveryNode, SearchPipelineInfo> entry : searchPipelineInfos.entrySet()) {
+                String type = processor.getType();
+                if (entry.getValue().containsProcessor(Pipeline.REQUEST_PROCESSORS_KEY, type) == false) {
+                    String message = "Processor type [" + processor.getType() + "] is not installed on node [" + entry.getKey() + "]";
+                    exceptions.add(ConfigurationUtils.newConfigurationException(processor.getType(), processor.getTag(), null, message));
+                }
+            }
+        }
+        for (SearchResponseProcessor processor : pipeline.getSearchResponseProcessors()) {
+            for (Map.Entry<DiscoveryNode, SearchPipelineInfo> entry : searchPipelineInfos.entrySet()) {
+                String type = processor.getType();
+                if (entry.getValue().containsProcessor(Pipeline.RESPONSE_PROCESSORS_KEY, type) == false) {
+                    String message = "Processor type [" + processor.getType() + "] is not installed on node [" + entry.getKey() + "]";
+                    exceptions.add(ConfigurationUtils.newConfigurationException(processor.getType(), processor.getTag(), null, message));
+                }
+            }
+        }
+        ExceptionsHelper.rethrowAndSuppress(exceptions);
+    }
+
+    public void deletePipeline(DeleteSearchPipelineRequest request, ActionListener<AcknowledgedResponse> listener) throws Exception {
+        clusterService.submitStateUpdateTask(
+            "delete-search-pipeline-" + request.getId(),
+            new AckedClusterStateUpdateTask<>(request, listener) {
+                @Override
+                public ClusterState execute(ClusterState currentState) {
+                    return innerDelete(request, currentState);
+                }
+
+                @Override
+                public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                    return deletePipelineTaskKey;
+                }
+
+                @Override
+                protected AcknowledgedResponse newResponse(boolean acknowledged) {
+                    return new AcknowledgedResponse(acknowledged);
+                }
+            }
+        );
+
+    }
+
+    static ClusterState innerDelete(DeleteSearchPipelineRequest request, ClusterState currentState) {
+        SearchPipelineMetadata currentMetadata = currentState.metadata().custom(SearchPipelineMetadata.TYPE);
+        if (currentMetadata == null) {
+            return currentState;
+        }
+        Map<String, PipelineConfiguration> pipelines = currentMetadata.getPipelines();
+        Set<String> toRemove = new HashSet<>();
+        for (String pipelineKey : pipelines.keySet()) {
+            if (Regex.simpleMatch(request.getId(), pipelineKey)) {
+                toRemove.add(pipelineKey);
+            }
+        }
+        if (toRemove.isEmpty()) {
+            if (Regex.isMatchAllPattern(request.getId())) {
+                // Deleting all the empty state is a no-op.
+                return currentState;
+            }
+            throw new ResourceNotFoundException("pipeline [{}] is missing", request.getId());
+        }
+        final Map<String, PipelineConfiguration> newPipelines = new HashMap<>(pipelines);
+        for (String key : toRemove) {
+            newPipelines.remove(key);
+        }
+        ClusterState.Builder newState = ClusterState.builder(currentState);
+        newState.metadata(
+            Metadata.builder(currentState.getMetadata()).putCustom(SearchPipelineMetadata.TYPE, new SearchPipelineMetadata(newPipelines))
+        );
+        return newState.build();
+    }
+
+    public PipelinedRequest resolvePipeline(SearchRequest searchRequest) {
+        Pipeline pipeline = Pipeline.NO_OP_PIPELINE;
+
+        if (searchRequest.source() != null && searchRequest.source().searchPipelineSource() != null) {
+            // Pipeline defined in search request (ad hoc pipeline).
+            if (searchRequest.pipeline() != null) {
+                throw new IllegalArgumentException(
+                    "Both named and inline search pipeline were specified. Please only specify one or the other."
+                );
+            }
+            try {
+                pipeline = PipelineWithMetrics.create(
+                    AD_HOC_PIPELINE_ID,
+                    searchRequest.source().searchPipelineSource(),
+                    requestProcessorFactories,
+                    responseProcessorFactories,
+                    phaseInjectorProcessorFactories,
+                    namedWriteableRegistry,
+                    totalRequestProcessingMetrics,
+                    totalResponseProcessingMetrics,
+                    new Processor.PipelineContext(Processor.PipelineSource.SEARCH_REQUEST)
+                );
+            } catch (Exception e) {
+                throw new SearchPipelineProcessingException(e);
+            }
+        } else {
+            String pipelineId = NOOP_PIPELINE_ID;
+            if (searchRequest.pipeline() != null) {
+                // Named pipeline specified for the request
+                pipelineId = searchRequest.pipeline();
+            } else if (state != null && searchRequest.indices() != null && searchRequest.indices().length == 1) {
+                // Check for index default pipeline
+                IndexMetadata indexMetadata = state.metadata().index(searchRequest.indices()[0]);
+                if (indexMetadata != null) {
+                    Settings indexSettings = indexMetadata.getSettings();
+                    if (IndexSettings.DEFAULT_SEARCH_PIPELINE.exists(indexSettings)) {
+                        pipelineId = IndexSettings.DEFAULT_SEARCH_PIPELINE.get(indexSettings);
+                    }
+                }
+            }
+            if (NOOP_PIPELINE_ID.equals(pipelineId) == false) {
+                PipelineHolder pipelineHolder = pipelines.get(pipelineId);
+                if (pipelineHolder == null) {
+                    throw new IllegalArgumentException("Pipeline " + pipelineId + " is not defined");
+                }
+                pipeline = pipelineHolder.pipeline;
+            }
+        }
+        SearchRequest transformedRequest = pipeline.transformRequest(searchRequest);
+        return new PipelinedRequest(pipeline, transformedRequest);
+    }
+
+    Map<String, Processor.Factory<SearchRequestProcessor>> getRequestProcessorFactories() {
+        return requestProcessorFactories;
+    }
+
+    Map<String, Processor.Factory<SearchResponseProcessor>> getResponseProcessorFactories() {
+        return responseProcessorFactories;
+    }
+
+    @Override
+    public SearchPipelineInfo info() {
+        List<ProcessorInfo> requestProcessorInfoList = requestProcessorFactories.keySet()
+            .stream()
+            .map(ProcessorInfo::new)
+            .collect(Collectors.toList());
+        List<ProcessorInfo> responseProcessorInfoList = responseProcessorFactories.keySet()
+            .stream()
+            .map(ProcessorInfo::new)
+            .collect(Collectors.toList());
+        return new SearchPipelineInfo(
+            Map.of(Pipeline.REQUEST_PROCESSORS_KEY, requestProcessorInfoList, Pipeline.RESPONSE_PROCESSORS_KEY, responseProcessorInfoList)
+        );
+    }
+
+    public SearchPipelineStats stats() {
+        SearchPipelineStats.Builder builder = new SearchPipelineStats.Builder();
+        builder.withTotalStats(totalRequestProcessingMetrics, totalResponseProcessingMetrics);
+        for (PipelineHolder pipelineHolder : pipelines.values()) {
+            PipelineWithMetrics pipeline = pipelineHolder.pipeline;
+            pipeline.populateStats(builder);
+        }
+        return builder.build();
+    }
+
+    public static List<PipelineConfiguration> getPipelines(ClusterState clusterState, String... ids) {
+        SearchPipelineMetadata metadata = clusterState.getMetadata().custom(SearchPipelineMetadata.TYPE);
+        return innerGetPipelines(metadata, ids);
+    }
+
+    static List<PipelineConfiguration> innerGetPipelines(SearchPipelineMetadata metadata, String... ids) {
+        if (metadata == null) {
+            return Collections.emptyList();
+        }
+
+        // if we didn't ask for _any_ ID, then we get them all (this is the same as if they ask for '*')
+        if (ids.length == 0) {
+            return new ArrayList<>(metadata.getPipelines().values());
+        }
+        List<PipelineConfiguration> result = new ArrayList<>(ids.length);
+        for (String id : ids) {
+            if (Regex.isSimpleMatchPattern(id)) {
+                for (Map.Entry<String, PipelineConfiguration> entry : metadata.getPipelines().entrySet()) {
+                    if (Regex.simpleMatch(id, entry.getKey())) {
+                        result.add(entry.getValue());
+                    }
+                }
+            } else {
+                PipelineConfiguration pipeline = metadata.getPipelines().get(id);
+                if (pipeline != null) {
+                    result.add(pipeline);
+                }
+            }
+        }
+        return result;
+    }
+
+    public ClusterService getClusterService() {
+        return clusterService;
+    }
+
+    Map<String, PipelineHolder> getPipelines() {
+        return pipelines;
+    }
+
+    static class PipelineHolder {
+
+        final PipelineConfiguration configuration;
+        final PipelineWithMetrics pipeline;
+
+        PipelineHolder(PipelineConfiguration configuration, PipelineWithMetrics pipeline) {
+            this.configuration = Objects.requireNonNull(configuration);
+            this.pipeline = Objects.requireNonNull(pipeline);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineStats.java b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineStats.java
new file mode 100644
index 0000000000000..68aca990f0f1e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchPipelineStats.java
@@ -0,0 +1,367 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.common.metrics.OperationMetrics;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.TreeMap;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.unmodifiableList;
+import static java.util.Collections.unmodifiableMap;
+
+/**
+ * Serializable, immutable search pipeline statistics to be returned via stats APIs.
+ *
+ * @opensearch.internal
+ */
+public class SearchPipelineStats implements Writeable, ToXContentFragment {
+
+    private final OperationStats totalRequestStats;
+    private final OperationStats totalResponseStats;
+    private final List<PerPipelineStats> perPipelineStats;
+    private final Map<String, PipelineDetailStats> perPipelineProcessorStats;
+
+    public SearchPipelineStats(
+        OperationStats totalRequestStats,
+        OperationStats totalResponseStats,
+        List<PerPipelineStats> perPipelineStats,
+        Map<String, PipelineDetailStats> perPipelineProcessorStats
+    ) {
+        this.totalRequestStats = totalRequestStats;
+        this.totalResponseStats = totalResponseStats;
+        this.perPipelineStats = perPipelineStats;
+        this.perPipelineProcessorStats = perPipelineProcessorStats;
+    }
+
+    public SearchPipelineStats(StreamInput in) throws IOException {
+        this.totalRequestStats = new OperationStats(in);
+        this.totalResponseStats = new OperationStats(in);
+        int size = in.readVInt();
+        List<PerPipelineStats> perPipelineStats = new ArrayList<>(size);
+        Map<String, PipelineDetailStats> pipelineDetailStatsMap = new TreeMap<>();
+        for (int i = 0; i < size; i++) {
+            String pipelineId = in.readString();
+            OperationStats pipelineRequestStats = new OperationStats(in);
+            OperationStats pipelineResponseStats = new OperationStats(in);
+            perPipelineStats.add(new PerPipelineStats(pipelineId, pipelineRequestStats, pipelineResponseStats));
+            int numRequestProcessors = in.readVInt();
+            List<ProcessorStats> requestProcessorStats = new ArrayList<>(numRequestProcessors);
+            for (int j = 0; j < numRequestProcessors; j++) {
+                String processorName = in.readString();
+                String processorType = in.readString();
+                OperationStats processorStats = new OperationStats(in);
+                requestProcessorStats.add(new ProcessorStats(processorName, processorType, processorStats));
+            }
+            int numResponseProcessors = in.readVInt();
+            List<ProcessorStats> responseProcessorStats = new ArrayList<>(numResponseProcessors);
+            for (int j = 0; j < numResponseProcessors; j++) {
+                String processorName = in.readString();
+                String processorType = in.readString();
+                OperationStats processorStats = new OperationStats(in);
+                responseProcessorStats.add(new ProcessorStats(processorName, processorType, processorStats));
+            }
+            pipelineDetailStatsMap.put(
+                pipelineId,
+                new PipelineDetailStats(unmodifiableList(requestProcessorStats), unmodifiableList(responseProcessorStats))
+            );
+        }
+        this.perPipelineStats = unmodifiableList(perPipelineStats);
+        this.perPipelineProcessorStats = unmodifiableMap(pipelineDetailStatsMap);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject("search_pipeline");
+        builder.startObject("total_request");
+        totalRequestStats.toXContent(builder, params);
+        builder.endObject();
+        builder.startObject("total_response");
+        totalResponseStats.toXContent(builder, params);
+        builder.endObject();
+        builder.startObject("pipelines");
+        for (PerPipelineStats pipelineStat : perPipelineStats) {
+            builder.startObject(pipelineStat.pipelineId);
+            builder.startObject("request");
+            pipelineStat.requestStats.toXContent(builder, params);
+            builder.endObject();
+            builder.startObject("response");
+            pipelineStat.responseStats.toXContent(builder, params);
+            builder.endObject();
+
+            PipelineDetailStats pipelineDetailStats = perPipelineProcessorStats.get(pipelineStat.pipelineId);
+            builder.startArray("request_processors");
+            for (ProcessorStats processorStats : pipelineDetailStats.requestProcessorStats) {
+                builder.startObject();
+                processorStats.toXContent(builder, params);
+                builder.endObject();
+            }
+            builder.endArray();
+            builder.startArray("response_processors");
+            for (ProcessorStats processorStats : pipelineDetailStats.responseProcessorStats) {
+                builder.startObject();
+                processorStats.toXContent(builder, params);
+                builder.endObject();
+            }
+            builder.endArray();
+            builder.endObject();
+        }
+        builder.endObject();
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        totalRequestStats.writeTo(out);
+        totalResponseStats.writeTo(out);
+        out.writeVInt(perPipelineStats.size());
+        for (PerPipelineStats pipelineStat : perPipelineStats) {
+            out.writeString(pipelineStat.pipelineId);
+            pipelineStat.requestStats.writeTo(out);
+            pipelineStat.responseStats.writeTo(out);
+            PipelineDetailStats pipelineDetailStats = perPipelineProcessorStats.get(pipelineStat.pipelineId);
+            out.writeVInt(pipelineDetailStats.requestProcessorStats.size());
+            for (ProcessorStats processorStats : pipelineDetailStats.requestProcessorStats) {
+                out.writeString(processorStats.processorName);
+                out.writeString(processorStats.processorType);
+                processorStats.stats.writeTo(out);
+            }
+            out.writeVInt(pipelineDetailStats.responseProcessorStats.size());
+            for (ProcessorStats processorStats : pipelineDetailStats.responseProcessorStats) {
+                out.writeString(processorStats.processorName);
+                out.writeString(processorStats.processorType);
+                processorStats.stats.writeTo(out);
+            }
+        }
+    }
+
+    static class Builder {
+        private OperationStats totalRequestStats;
+        private OperationStats totalResponseStats;
+        private final List<PerPipelineStats> perPipelineStats = new ArrayList<>();
+        private final Map<String, List<ProcessorStats>> requestProcessorStatsPerPipeline = new HashMap<>();
+        private final Map<String, List<ProcessorStats>> responseProcessorStatsPerPipeline = new HashMap<>();
+
+        Builder withTotalStats(OperationMetrics totalRequestMetrics, OperationMetrics totalResponseMetrics) {
+            this.totalRequestStats = totalRequestMetrics.createStats();
+            this.totalResponseStats = totalResponseMetrics.createStats();
+            return this;
+        }
+
+        Builder addPipelineStats(String pipelineId, OperationMetrics pipelineRequestMetrics, OperationMetrics pipelineResponseMetrics) {
+            this.perPipelineStats.add(
+                new PerPipelineStats(pipelineId, pipelineRequestMetrics.createStats(), pipelineResponseMetrics.createStats())
+            );
+            return this;
+        }
+
+        Builder addRequestProcessorStats(String pipelineId, String processorName, String processorType, OperationMetrics processorMetrics) {
+            this.requestProcessorStatsPerPipeline.computeIfAbsent(pipelineId, k -> new ArrayList<>())
+                .add(new ProcessorStats(processorName, processorType, processorMetrics.createStats()));
+            return this;
+        }
+
+        Builder addResponseProcessorStats(
+            String pipelineId,
+            String processorName,
+            String processorType,
+            OperationMetrics processorMetrics
+        ) {
+            this.responseProcessorStatsPerPipeline.computeIfAbsent(pipelineId, k -> new ArrayList<>())
+                .add(new ProcessorStats(processorName, processorType, processorMetrics.createStats()));
+            return this;
+        }
+
+        SearchPipelineStats build() {
+            Map<String, PipelineDetailStats> pipelineDetailStatsMap = new TreeMap<>();
+            for (PerPipelineStats pipelineStat : perPipelineStats) {
+                List<ProcessorStats> requestProcessorStats = requestProcessorStatsPerPipeline.getOrDefault(
+                    pipelineStat.pipelineId,
+                    emptyList()
+                );
+                List<ProcessorStats> responseProcessorStats = responseProcessorStatsPerPipeline.getOrDefault(
+                    pipelineStat.pipelineId,
+                    emptyList()
+                );
+                PipelineDetailStats pipelineDetailStats = new PipelineDetailStats(
+                    unmodifiableList(requestProcessorStats),
+                    unmodifiableList(responseProcessorStats)
+                );
+                pipelineDetailStatsMap.put(pipelineStat.pipelineId, pipelineDetailStats);
+            }
+            return new SearchPipelineStats(
+                totalRequestStats,
+                totalResponseStats,
+                unmodifiableList(perPipelineStats),
+                unmodifiableMap(pipelineDetailStatsMap)
+            );
+        }
+    }
+
+    static class PerPipelineStats {
+        private final String pipelineId;
+        private final OperationStats requestStats;
+        private final OperationStats responseStats;
+
+        public PerPipelineStats(String pipelineId, OperationStats requestStats, OperationStats responseStats) {
+            this.pipelineId = pipelineId;
+            this.requestStats = requestStats;
+            this.responseStats = responseStats;
+        }
+
+        public String getPipelineId() {
+            return pipelineId;
+        }
+
+        public OperationStats getRequestStats() {
+            return requestStats;
+        }
+
+        public OperationStats getResponseStats() {
+            return responseStats;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            PerPipelineStats that = (PerPipelineStats) o;
+            return pipelineId.equals(that.pipelineId) && requestStats.equals(that.requestStats) && responseStats.equals(that.responseStats);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(pipelineId, requestStats, responseStats);
+        }
+    }
+
+    static class PipelineDetailStats {
+        private final List<ProcessorStats> requestProcessorStats;
+        private final List<ProcessorStats> responseProcessorStats;
+
+        public PipelineDetailStats(List<ProcessorStats> requestProcessorStats, List<ProcessorStats> responseProcessorStats) {
+            this.requestProcessorStats = requestProcessorStats;
+            this.responseProcessorStats = responseProcessorStats;
+        }
+
+        public List<ProcessorStats> requestProcessorStats() {
+            return requestProcessorStats;
+        }
+
+        public List<ProcessorStats> responseProcessorStats() {
+            return responseProcessorStats;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            PipelineDetailStats that = (PipelineDetailStats) o;
+            return requestProcessorStats.equals(that.requestProcessorStats) && responseProcessorStats.equals(that.responseProcessorStats);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(requestProcessorStats, responseProcessorStats);
+        }
+    }
+
+    static class ProcessorStats implements ToXContentFragment {
+        private final String processorName; // type:tag
+        private final String processorType;
+        private final OperationStats stats;
+
+        public ProcessorStats(String processorName, String processorType, OperationStats stats) {
+            this.processorName = processorName;
+            this.processorType = processorType;
+            this.stats = stats;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            ProcessorStats that = (ProcessorStats) o;
+            return processorName.equals(that.processorName) && processorType.equals(that.processorType) && stats.equals(that.stats);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(processorName, processorType, stats);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject(processorName);
+            builder.field("type", processorType);
+            builder.startObject("stats");
+            stats.toXContent(builder, params);
+            builder.endObject();
+            builder.endObject();
+            return builder;
+        }
+
+        String getProcessorName() {
+            return processorName;
+        }
+
+        String getProcessorType() {
+            return processorType;
+        }
+
+        OperationStats getStats() {
+            return stats;
+        }
+    }
+
+    OperationStats getTotalRequestStats() {
+        return totalRequestStats;
+    }
+
+    OperationStats getTotalResponseStats() {
+        return totalResponseStats;
+    }
+
+    List<PerPipelineStats> getPipelineStats() {
+        return perPipelineStats;
+    }
+
+    Map<String, PipelineDetailStats> getPerPipelineProcessorStats() {
+        return perPipelineProcessorStats;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchPipelineStats stats = (SearchPipelineStats) o;
+        return totalRequestStats.equals(stats.totalRequestStats)
+            && totalResponseStats.equals(stats.totalResponseStats)
+            && perPipelineStats.equals(stats.perPipelineStats)
+            && perPipelineProcessorStats.equals(stats.perPipelineProcessorStats);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(totalRequestStats, totalResponseStats, perPipelineStats, perPipelineProcessorStats);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchRequestProcessor.java b/server/src/main/java/org/opensearch/search/pipeline/SearchRequestProcessor.java
new file mode 100644
index 0000000000000..c236cde1a5cc0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchRequestProcessor.java
@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.action.search.SearchRequest;
+
+/**
+ * Interface for a search pipeline processor that modifies a search request.
+ */
+public interface SearchRequestProcessor extends Processor {
+    SearchRequest processRequest(SearchRequest request) throws Exception;
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/SearchResponseProcessor.java b/server/src/main/java/org/opensearch/search/pipeline/SearchResponseProcessor.java
new file mode 100644
index 0000000000000..2f22cedb9b5c0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/SearchResponseProcessor.java
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+
+/**
+ * Interface for a search pipeline processor that modifies a search response.
+ */
+public interface SearchResponseProcessor extends Processor {
+    SearchResponse processResponse(SearchRequest request, SearchResponse response) throws Exception;
+}
diff --git a/server/src/main/java/org/opensearch/search/pipeline/package-info.java b/server/src/main/java/org/opensearch/search/pipeline/package-info.java
new file mode 100644
index 0000000000000..91573d06e8f76
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/pipeline/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Search pipelines base package. */
+package org.opensearch.search.pipeline;
diff --git a/server/src/main/java/org/opensearch/search/profile/AbstractInternalProfileTree.java b/server/src/main/java/org/opensearch/search/profile/AbstractInternalProfileTree.java
index e797f3749d52d..4d0949624ebed 100644
--- a/server/src/main/java/org/opensearch/search/profile/AbstractInternalProfileTree.java
+++ b/server/src/main/java/org/opensearch/search/profile/AbstractInternalProfileTree.java
@@ -40,6 +40,11 @@
 import java.util.Deque;
 import java.util.List;
 
+/**
+ * Base class for a profiling tree.
+ *
+ * @opensearch.internal
+ */
 public abstract class AbstractInternalProfileTree<PB extends AbstractProfileBreakdown<?>, E> {
 
     protected ArrayList<PB> breakdowns;
diff --git a/server/src/main/java/org/opensearch/search/profile/AbstractProfileBreakdown.java b/server/src/main/java/org/opensearch/search/profile/AbstractProfileBreakdown.java
index d3bbd4d59e53e..67ab062c0e3ca 100644
--- a/server/src/main/java/org/opensearch/search/profile/AbstractProfileBreakdown.java
+++ b/server/src/main/java/org/opensearch/search/profile/AbstractProfileBreakdown.java
@@ -42,14 +42,18 @@
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc).
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractProfileBreakdown<T extends Enum<T>> {
 
     /**
      * The accumulated timings for this query node
      */
-    private final Timer[] timings;
-    private final T[] timingTypes;
+    protected final Timer[] timings;
+    protected final T[] timingTypes;
+    public static final String TIMING_TYPE_COUNT_SUFFIX = "_count";
+    public static final String TIMING_TYPE_START_TIME_SUFFIX = "_start_time";
 
     /** Sole constructor. */
     public AbstractProfileBreakdown(Class<T> clazz) {
@@ -72,17 +76,10 @@ public void setTimer(T timing, Timer timer) {
      * Build a timing count breakdown for current instance
      */
     public Map<String, Long> toBreakdownMap() {
-        return buildBreakdownMap(this);
-    }
-
-    /**
-     * Build a timing count breakdown for arbitrary instance
-     */
-    protected final Map<String, Long> buildBreakdownMap(AbstractProfileBreakdown<T> breakdown) {
-        Map<String, Long> map = new HashMap<>(breakdown.timings.length * 2);
-        for (T timingType : breakdown.timingTypes) {
-            map.put(timingType.toString(), breakdown.timings[timingType.ordinal()].getApproximateTiming());
-            map.put(timingType.toString() + "_count", breakdown.timings[timingType.ordinal()].getCount());
+        Map<String, Long> map = new HashMap<>(this.timings.length * 3);
+        for (T timingType : this.timingTypes) {
+            map.put(timingType.toString(), this.timings[timingType.ordinal()].getApproximateTiming());
+            map.put(timingType + TIMING_TYPE_COUNT_SUFFIX, this.timings[timingType.ordinal()].getCount());
         }
         return Collections.unmodifiableMap(map);
     }
diff --git a/server/src/main/java/org/opensearch/search/profile/AbstractProfiler.java b/server/src/main/java/org/opensearch/search/profile/AbstractProfiler.java
index b8e8ad2924cad..4db1cb87a231d 100644
--- a/server/src/main/java/org/opensearch/search/profile/AbstractProfiler.java
+++ b/server/src/main/java/org/opensearch/search/profile/AbstractProfiler.java
@@ -34,6 +34,11 @@
 
 import java.util.List;
 
+/**
+ * Base class for a profiler
+ *
+ * @opensearch.internal
+ */
 public class AbstractProfiler<PB extends AbstractProfileBreakdown<?>, E> {
 
     protected final AbstractInternalProfileTree<PB, E> profileTree;
diff --git a/server/src/main/java/org/opensearch/search/profile/ContextualProfileBreakdown.java b/server/src/main/java/org/opensearch/search/profile/ContextualProfileBreakdown.java
index 42cb16e88b4a9..4f071f730cd45 100644
--- a/server/src/main/java/org/opensearch/search/profile/ContextualProfileBreakdown.java
+++ b/server/src/main/java/org/opensearch/search/profile/ContextualProfileBreakdown.java
@@ -11,6 +11,8 @@
 /**
  * Provide contextual profile breakdowns which are associated with freestyle context. Used when concurrent
  * search over segments is activated and each collector needs own non-shareable profile breakdown instance.
+ *
+ * @opensearch.internal
  */
 public abstract class ContextualProfileBreakdown<T extends Enum<T>> extends AbstractProfileBreakdown<T> {
     public ContextualProfileBreakdown(Class<T> clazz) {
diff --git a/server/src/main/java/org/opensearch/search/profile/NetworkTime.java b/server/src/main/java/org/opensearch/search/profile/NetworkTime.java
index 8a9c72af5dcb0..45d8c2883cb4a 100644
--- a/server/src/main/java/org/opensearch/search/profile/NetworkTime.java
+++ b/server/src/main/java/org/opensearch/search/profile/NetworkTime.java
@@ -9,12 +9,17 @@
 package org.opensearch.search.profile;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Utility class to track time of network operations
+ *
+ * @opensearch.internal
+ */
 public class NetworkTime implements Writeable {
     private long inboundNetworkTime;
     private long outboundNetworkTime;
diff --git a/server/src/main/java/org/opensearch/search/profile/ProfileResult.java b/server/src/main/java/org/opensearch/search/profile/ProfileResult.java
index ad14431797ea2..707f6eab32e07 100644
--- a/server/src/main/java/org/opensearch/search/profile/ProfileResult.java
+++ b/server/src/main/java/org/opensearch/search/profile/ProfileResult.java
@@ -33,25 +33,28 @@
 package org.opensearch.search.profile;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.Version;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.InstantiatingObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.InstantiatingObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * This class is the internal representation of a profiled Query, corresponding
@@ -61,6 +64,8 @@
  * <p>
  * Each InternalProfileResult has a List of InternalProfileResults, which will contain
  * "children" queries if applicable
+ *
+ * @opensearch.internal
  */
 public final class ProfileResult implements Writeable, ToXContentObject {
     static final ParseField TYPE = new ParseField("type");
@@ -68,7 +73,13 @@ public final class ProfileResult implements Writeable, ToXContentObject {
     static final ParseField BREAKDOWN = new ParseField("breakdown");
     static final ParseField DEBUG = new ParseField("debug");
     static final ParseField NODE_TIME = new ParseField("time");
+    static final ParseField MAX_SLICE_NODE_TIME = new ParseField("max_slice_time");
+    static final ParseField MIN_SLICE_NODE_TIME = new ParseField("min_slice_time");
+    static final ParseField AVG_SLICE_NODE_TIME = new ParseField("avg_slice_time");
     static final ParseField NODE_TIME_RAW = new ParseField("time_in_nanos");
+    static final ParseField MAX_SLICE_NODE_TIME_RAW = new ParseField("max_slice_time_in_nanos");
+    static final ParseField MIN_SLICE_NODE_TIME_RAW = new ParseField("min_slice_time_in_nanos");
+    static final ParseField AVG_SLICE_NODE_TIME_RAW = new ParseField("avg_slice_time_in_nanos");
     static final ParseField CHILDREN = new ParseField("children");
 
     private final String type;
@@ -76,6 +87,9 @@ public final class ProfileResult implements Writeable, ToXContentObject {
     private final Map<String, Long> breakdown;
     private final Map<String, Object> debug;
     private final long nodeTime;
+    private Long maxSliceNodeTime;
+    private Long minSliceNodeTime;
+    private Long avgSliceNodeTime;
     private final List<ProfileResult> children;
 
     public ProfileResult(
@@ -85,13 +99,30 @@ public ProfileResult(
         Map<String, Object> debug,
         long nodeTime,
         List<ProfileResult> children
+    ) {
+        this(type, description, breakdown, debug, nodeTime, children, null, null, null);
+    }
+
+    public ProfileResult(
+        String type,
+        String description,
+        Map<String, Long> breakdown,
+        Map<String, Object> debug,
+        long nodeTime,
+        List<ProfileResult> children,
+        Long maxSliceNodeTime,
+        Long minSliceNodeTime,
+        Long avgSliceNodeTime
     ) {
         this.type = type;
         this.description = description;
         this.breakdown = Objects.requireNonNull(breakdown, "required breakdown argument missing");
-        this.debug = debug == null ? org.opensearch.common.collect.Map.of() : debug;
-        this.children = children == null ? org.opensearch.common.collect.List.of() : children;
+        this.debug = debug == null ? Map.of() : debug;
+        this.children = children == null ? List.of() : children;
         this.nodeTime = nodeTime;
+        this.maxSliceNodeTime = maxSliceNodeTime;
+        this.minSliceNodeTime = minSliceNodeTime;
+        this.avgSliceNodeTime = avgSliceNodeTime;
     }
 
     /**
@@ -105,9 +136,18 @@ public ProfileResult(StreamInput in) throws IOException {
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_9_0)) {
             debug = in.readMap(StreamInput::readString, StreamInput::readGenericValue);
         } else {
-            debug = org.opensearch.common.collect.Map.of();
+            debug = Map.of();
         }
         children = in.readList(ProfileResult::new);
+        if (in.getVersion().onOrAfter(Version.V_2_10_0)) {
+            this.maxSliceNodeTime = in.readOptionalLong();
+            this.minSliceNodeTime = in.readOptionalLong();
+            this.avgSliceNodeTime = in.readOptionalLong();
+        } else {
+            this.maxSliceNodeTime = null;
+            this.minSliceNodeTime = null;
+            this.avgSliceNodeTime = null;
+        }
     }
 
     @Override
@@ -120,6 +160,11 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeMap(debug, StreamOutput::writeString, StreamOutput::writeGenericValue);
         }
         out.writeList(children);
+        if (out.getVersion().onOrAfter(Version.V_2_10_0)) {
+            out.writeOptionalLong(maxSliceNodeTime);
+            out.writeOptionalLong(minSliceNodeTime);
+            out.writeOptionalLong(avgSliceNodeTime);
+        }
     }
 
     /**
@@ -159,6 +204,18 @@ public long getTime() {
         return nodeTime;
     }
 
+    public Long getMaxSliceTime() {
+        return maxSliceNodeTime;
+    }
+
+    public Long getMinSliceTime() {
+        return minSliceNodeTime;
+    }
+
+    public Long getAvgSliceTime() {
+        return avgSliceNodeTime;
+    }
+
     /**
      * Returns a list of all profiled children queries
      */
@@ -173,9 +230,27 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         builder.field(DESCRIPTION.getPreferredName(), description);
         if (builder.humanReadable()) {
             builder.field(NODE_TIME.getPreferredName(), new TimeValue(getTime(), TimeUnit.NANOSECONDS).toString());
+            if (getMaxSliceTime() != null) {
+                builder.field(MAX_SLICE_NODE_TIME.getPreferredName(), new TimeValue(getMaxSliceTime(), TimeUnit.NANOSECONDS).toString());
+            }
+            if (getMinSliceTime() != null) {
+                builder.field(MIN_SLICE_NODE_TIME.getPreferredName(), new TimeValue(getMinSliceTime(), TimeUnit.NANOSECONDS).toString());
+            }
+            if (getAvgSliceTime() != null) {
+                builder.field(AVG_SLICE_NODE_TIME.getPreferredName(), new TimeValue(getAvgSliceTime(), TimeUnit.NANOSECONDS).toString());
+            }
         }
         builder.field(NODE_TIME_RAW.getPreferredName(), getTime());
-        builder.field(BREAKDOWN.getPreferredName(), breakdown);
+        if (getMaxSliceTime() != null) {
+            builder.field(MAX_SLICE_NODE_TIME_RAW.getPreferredName(), getMaxSliceTime());
+        }
+        if (getMinSliceTime() != null) {
+            builder.field(MIN_SLICE_NODE_TIME_RAW.getPreferredName(), getMinSliceTime());
+        }
+        if (getAvgSliceTime() != null) {
+            builder.field(AVG_SLICE_NODE_TIME_RAW.getPreferredName(), getAvgSliceTime());
+        }
+        createBreakdownView(builder);
         if (false == debug.isEmpty()) {
             builder.field(DEBUG.getPreferredName(), debug);
         }
@@ -191,6 +266,22 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder.endObject();
     }
 
+    private void createBreakdownView(XContentBuilder builder) throws IOException {
+        Map<String, Long> modifiedBreakdown = new LinkedHashMap<>(breakdown);
+        removeStartTimeFields(modifiedBreakdown);
+        builder.field(BREAKDOWN.getPreferredName(), modifiedBreakdown);
+    }
+
+    static void removeStartTimeFields(Map<String, Long> modifiedBreakdown) {
+        Iterator<Map.Entry<String, Long>> iterator = modifiedBreakdown.entrySet().iterator();
+        while (iterator.hasNext()) {
+            Map.Entry<String, Long> entry = iterator.next();
+            if (entry.getKey().endsWith(AbstractProfileBreakdown.TIMING_TYPE_START_TIME_SUFFIX)) {
+                iterator.remove();
+            }
+        }
+    }
+
     private static final InstantiatingObjectParser<ProfileResult, Void> PARSER;
     static {
         InstantiatingObjectParser.Builder<ProfileResult, Void> parser = InstantiatingObjectParser.builder(
@@ -204,6 +295,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         parser.declareObject(optionalConstructorArg(), (p, c) -> p.map(), DEBUG);
         parser.declareLong(constructorArg(), NODE_TIME_RAW);
         parser.declareObjectArray(optionalConstructorArg(), (p, c) -> fromXContent(p), CHILDREN);
+        parser.declareLong(optionalConstructorArg(), MAX_SLICE_NODE_TIME_RAW);
+        parser.declareLong(optionalConstructorArg(), MIN_SLICE_NODE_TIME_RAW);
+        parser.declareLong(optionalConstructorArg(), AVG_SLICE_NODE_TIME_RAW);
         PARSER = parser.build();
     }
 
diff --git a/server/src/main/java/org/opensearch/search/profile/ProfileShardResult.java b/server/src/main/java/org/opensearch/search/profile/ProfileShardResult.java
index c368225473f3d..502d8e4852588 100644
--- a/server/src/main/java/org/opensearch/search/profile/ProfileShardResult.java
+++ b/server/src/main/java/org/opensearch/search/profile/ProfileShardResult.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.profile;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.profile.aggregation.AggregationProfileShardResult;
 import org.opensearch.search.profile.query.QueryProfileShardResult;
 
@@ -43,6 +43,11 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Shard level profile results
+ *
+ * @opensearch.internal
+ */
 public class ProfileShardResult implements Writeable {
 
     private final List<QueryProfileShardResult> queryProfileResults;
diff --git a/server/src/main/java/org/opensearch/search/profile/Profilers.java b/server/src/main/java/org/opensearch/search/profile/Profilers.java
index 6b9be0167b50f..8e87c7ff4acd4 100644
--- a/server/src/main/java/org/opensearch/search/profile/Profilers.java
+++ b/server/src/main/java/org/opensearch/search/profile/Profilers.java
@@ -34,30 +34,37 @@
 
 import org.opensearch.search.internal.ContextIndexSearcher;
 import org.opensearch.search.profile.aggregation.AggregationProfiler;
+import org.opensearch.search.profile.aggregation.ConcurrentAggregationProfiler;
 import org.opensearch.search.profile.query.QueryProfiler;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-/** Wrapper around all the profilers that makes management easier. */
+/**
+ * Wrapper around all the profilers that makes management easier.
+ *
+ * @opensearch.internal
+ */
 public final class Profilers {
 
     private final ContextIndexSearcher searcher;
     private final List<QueryProfiler> queryProfilers;
     private final AggregationProfiler aggProfiler;
+    private final boolean isConcurrentSegmentSearchEnabled;
 
     /** Sole constructor. This {@link Profilers} instance will initially wrap one {@link QueryProfiler}. */
-    public Profilers(ContextIndexSearcher searcher) {
+    public Profilers(ContextIndexSearcher searcher, boolean isConcurrentSegmentSearchEnabled) {
         this.searcher = searcher;
+        this.isConcurrentSegmentSearchEnabled = isConcurrentSegmentSearchEnabled;
         this.queryProfilers = new ArrayList<>();
-        this.aggProfiler = new AggregationProfiler();
+        this.aggProfiler = isConcurrentSegmentSearchEnabled ? new ConcurrentAggregationProfiler() : new AggregationProfiler();
         addQueryProfiler();
     }
 
     /** Switch to a new profile. */
     public QueryProfiler addQueryProfiler() {
-        QueryProfiler profiler = new QueryProfiler(searcher.allowConcurrentSegmentSearch());
+        QueryProfiler profiler = new QueryProfiler(isConcurrentSegmentSearchEnabled);
         searcher.setProfiler(profiler);
         queryProfilers.add(profiler);
         return profiler;
diff --git a/server/src/main/java/org/opensearch/search/profile/SearchProfileShardResults.java b/server/src/main/java/org/opensearch/search/profile/SearchProfileShardResults.java
index 4765b7651900b..53cf1f2739e77 100644
--- a/server/src/main/java/org/opensearch/search/profile/SearchProfileShardResults.java
+++ b/server/src/main/java/org/opensearch/search/profile/SearchProfileShardResults.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.profile;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.profile.aggregation.AggregationProfileShardResult;
 import org.opensearch.search.profile.aggregation.AggregationProfiler;
@@ -52,11 +52,13 @@
 import java.util.Map;
 import java.util.TreeSet;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A container class to hold all the profile results across all shards.  Internally
  * holds a map of shard ID -&gt; Profiled results
+ *
+ * @opensearch.internal
  */
 public final class SearchProfileShardResults implements Writeable, ToXContentFragment {
     private static final String SEARCHES_FIELD = "searches";
diff --git a/server/src/main/java/org/opensearch/search/profile/Timer.java b/server/src/main/java/org/opensearch/search/profile/Timer.java
index d392110e53382..172762cabeb6a 100644
--- a/server/src/main/java/org/opensearch/search/profile/Timer.java
+++ b/server/src/main/java/org/opensearch/search/profile/Timer.java
@@ -45,11 +45,13 @@
  *    timer.stop();
  *  }
  *  </pre>
+ *
+ *  @opensearch.internal
  */
 public class Timer {
 
     private boolean doTiming;
-    private long timing, count, lastCount, start;
+    private long timing, count, lastCount, start, earliestTimerStartTime;
 
     /** pkg-private for testing */
     long nanoTime() {
@@ -69,6 +71,9 @@ public final void start() {
         doTiming = (count - lastCount) >= Math.min(lastCount >>> 8, 1024);
         if (doTiming) {
             start = nanoTime();
+            if (count == 0) {
+                earliestTimerStartTime = start;
+            }
         }
         count++;
     }
@@ -90,6 +95,14 @@ public final long getCount() {
         return count;
     }
 
+    /** Return the timer start time in nanoseconds.*/
+    public final long getEarliestTimerStartTime() {
+        if (start != 0) {
+            throw new IllegalStateException("#start call misses a matching #stop call");
+        }
+        return earliestTimerStartTime;
+    }
+
     /** Return an approximation of the total time spent between consecutive calls of #start and #stop. */
     public final long getApproximateTiming() {
         if (start != 0) {
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileBreakdown.java b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileBreakdown.java
index 4c3b22a02cc3e..d0c67915e6d8d 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileBreakdown.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileBreakdown.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.search.profile.AbstractProfileBreakdown;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -41,6 +42,8 @@
 
 /**
  * {@linkplain AbstractProfileBreakdown} customized to work with aggregations.
+ *
+ * @opensearch.internal
  */
 public class AggregationProfileBreakdown extends AbstractProfileBreakdown<AggregationTimingType> {
     private final Map<String, Object> extra = new HashMap<>();
@@ -60,4 +63,18 @@ public void addDebugInfo(String key, Object value) {
     protected Map<String, Object> toDebugMap() {
         return unmodifiableMap(extra);
     }
+
+    /**
+     * Build a timing count startTime breakdown for aggregation timing types
+     */
+    @Override
+    public Map<String, Long> toBreakdownMap() {
+        Map<String, Long> map = new HashMap<>(timings.length * 3);
+        for (AggregationTimingType timingType : timingTypes) {
+            map.put(timingType.toString(), timings[timingType.ordinal()].getApproximateTiming());
+            map.put(timingType + TIMING_TYPE_COUNT_SUFFIX, timings[timingType.ordinal()].getCount());
+            map.put(timingType + TIMING_TYPE_START_TIME_SUFFIX, timings[timingType.ordinal()].getEarliestTimerStartTime());
+        }
+        return Collections.unmodifiableMap(map);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResult.java b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResult.java
index 1638b3ee4d8c7..046e929821ab5 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResult.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResult.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.profile.aggregation;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.profile.ProfileResult;
 
 import java.io.IOException;
@@ -45,11 +45,13 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A container class to hold the profile results for a single shard in the request.
  * Contains a list of query profiles, a collector tree and a total rewrite tree.
+ *
+ * @opensearch.internal
  */
 public final class AggregationProfileShardResult implements Writeable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfiler.java b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfiler.java
index 7a1115e8b9e4c..39620c25dc5a3 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfiler.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationProfiler.java
@@ -36,35 +36,34 @@
 import org.opensearch.search.profile.AbstractProfiler;
 
 import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
 import java.util.Map;
 
+/**
+ * Main class to profile aggregations
+ *
+ * @opensearch.internal
+ */
 public class AggregationProfiler extends AbstractProfiler<AggregationProfileBreakdown, Aggregator> {
 
-    private final Map<List<String>, AggregationProfileBreakdown> profileBreakdownLookup = new HashMap<>();
+    private final Map<Aggregator, AggregationProfileBreakdown> profileBreakdownLookup = new HashMap<>();
 
     public AggregationProfiler() {
         super(new InternalAggregationProfileTree());
     }
 
+    /**
+     * This method does not need to be thread safe for concurrent search use case as well.
+     * The {@link AggregationProfileBreakdown} for each Aggregation operator is created in sync path when
+     * {@link org.opensearch.search.aggregations.BucketCollector#preCollection()} is called
+     * on the Aggregation collector instances during construction.
+     */
     @Override
     public AggregationProfileBreakdown getQueryBreakdown(Aggregator agg) {
-        List<String> path = getAggregatorPath(agg);
-        AggregationProfileBreakdown aggregationProfileBreakdown = profileBreakdownLookup.get(path);
+        AggregationProfileBreakdown aggregationProfileBreakdown = profileBreakdownLookup.get(agg);
         if (aggregationProfileBreakdown == null) {
             aggregationProfileBreakdown = super.getQueryBreakdown(agg);
-            profileBreakdownLookup.put(path, aggregationProfileBreakdown);
+            profileBreakdownLookup.put(agg, aggregationProfileBreakdown);
         }
         return aggregationProfileBreakdown;
     }
-
-    public static List<String> getAggregatorPath(Aggregator agg) {
-        LinkedList<String> path = new LinkedList<>();
-        while (agg != null) {
-            path.addFirst(agg.name());
-            agg = agg.parent();
-        }
-        return path;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationTimingType.java b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationTimingType.java
index d71ca06941fbc..8c5ea2613e926 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationTimingType.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/AggregationTimingType.java
@@ -34,6 +34,11 @@
 
 import java.util.Locale;
 
+/**
+ * Timing levels for aggregations
+ *
+ * @opensearch.internal
+ */
 public enum AggregationTimingType {
     INITIALIZE,
     BUILD_LEAF_COLLECTOR,
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfiler.java b/server/src/main/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfiler.java
new file mode 100644
index 0000000000000..deed68c535cf9
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfiler.java
@@ -0,0 +1,199 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.profile.aggregation;
+
+import org.opensearch.search.profile.AbstractProfileBreakdown;
+import org.opensearch.search.profile.ProfileResult;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Main class to profile aggregations with concurrent execution
+ *
+ * @opensearch.internal
+ */
+public class ConcurrentAggregationProfiler extends AggregationProfiler {
+
+    private static final String MAX_PREFIX = "max_";
+    private static final String MIN_PREFIX = "min_";
+    private static final String AVG_PREFIX = "avg_";
+    private static final String START_TIME_KEY = AggregationTimingType.INITIALIZE + AbstractProfileBreakdown.TIMING_TYPE_START_TIME_SUFFIX;
+    private static final String[] breakdownCountStatsTypes = { "build_leaf_collector_count", "collect_count" };
+
+    @Override
+    public List<ProfileResult> getTree() {
+        List<ProfileResult> tree = profileTree.getTree();
+        List<ProfileResult> reducedTree = new LinkedList<>();
+        Map<String, List<ProfileResult>> sliceLevelAggregationMap = getSliceLevelAggregationMap(tree);
+        for (List<ProfileResult> profileResultsAcrossSlices : sliceLevelAggregationMap.values()) {
+            reducedTree.addAll(reduceProfileResultsTree(profileResultsAcrossSlices));
+        }
+        return reducedTree;
+    }
+
+    private List<ProfileResult> reduceProfileResultsTree(List<ProfileResult> profileResultsAcrossSlices) {
+        String type = profileResultsAcrossSlices.get(0).getQueryName();
+        String description = profileResultsAcrossSlices.get(0).getLuceneDescription();
+        long maxSliceNodeEndTime = Long.MIN_VALUE;
+        long minSliceNodeStartTime = Long.MAX_VALUE;
+        long maxSliceNodeTime = Long.MIN_VALUE;
+        long minSliceNodeTime = Long.MAX_VALUE;
+        long avgSliceNodeTime = 0L;
+        Map<String, Long> breakdown = new HashMap<>();
+        Map<String, Long> timeStatsMap = new HashMap<>();
+        Map<String, Long> minSliceStartTimeMap = new HashMap<>();
+        Map<String, Long> maxSliceEndTimeMap = new HashMap<>();
+        Map<String, Long> countStatsMap = new HashMap<>();
+        Map<String, Object> debug = new HashMap<>();
+        List<ProfileResult> children = new LinkedList<>();
+
+        for (ProfileResult profileResult : profileResultsAcrossSlices) {
+            long profileNodeTime = profileResult.getTime();
+            long sliceStartTime = profileResult.getTimeBreakdown().get(START_TIME_KEY);
+
+            // Profiled total time
+            maxSliceNodeEndTime = Math.max(maxSliceNodeEndTime, sliceStartTime + profileNodeTime);
+            minSliceNodeStartTime = Math.min(minSliceNodeStartTime, sliceStartTime);
+
+            // Profiled total time stats
+            maxSliceNodeTime = Math.max(maxSliceNodeTime, profileNodeTime);
+            minSliceNodeTime = Math.min(minSliceNodeTime, profileNodeTime);
+            avgSliceNodeTime += profileNodeTime;
+
+            // Profiled breakdown time stats
+            for (AggregationTimingType timingType : AggregationTimingType.values()) {
+                buildBreakdownStatsMap(timeStatsMap, profileResult, timingType.toString());
+            }
+
+            // Profiled breakdown total time
+            for (AggregationTimingType timingType : AggregationTimingType.values()) {
+                String breakdownTimingType = timingType.toString();
+                Long startTime = profileResult.getTimeBreakdown()
+                    .get(breakdownTimingType + AbstractProfileBreakdown.TIMING_TYPE_START_TIME_SUFFIX);
+                Long endTime = startTime + profileResult.getTimeBreakdown().get(breakdownTimingType);
+                minSliceStartTimeMap.put(
+                    breakdownTimingType,
+                    Math.min(minSliceStartTimeMap.getOrDefault(breakdownTimingType, Long.MAX_VALUE), startTime)
+                );
+                maxSliceEndTimeMap.put(
+                    breakdownTimingType,
+                    Math.max(maxSliceEndTimeMap.getOrDefault(breakdownTimingType, Long.MIN_VALUE), endTime)
+                );
+            }
+
+            // Profiled breakdown count stats
+            for (String breakdownCountType : breakdownCountStatsTypes) {
+                buildBreakdownStatsMap(countStatsMap, profileResult, breakdownCountType);
+            }
+
+            // Profiled breakdown count
+            for (AggregationTimingType timingType : AggregationTimingType.values()) {
+                String breakdownType = timingType.toString();
+                String breakdownTypeCount = breakdownType + AbstractProfileBreakdown.TIMING_TYPE_COUNT_SUFFIX;
+                breakdown.put(
+                    breakdownTypeCount,
+                    breakdown.getOrDefault(breakdownTypeCount, 0L) + profileResult.getTimeBreakdown().get(breakdownTypeCount)
+                );
+            }
+
+            debug = profileResult.getDebugInfo();
+            children.addAll(profileResult.getProfiledChildren());
+        }
+        // nodeTime
+        long nodeTime = maxSliceNodeEndTime - minSliceNodeStartTime;
+        avgSliceNodeTime /= profileResultsAcrossSlices.size();
+
+        // Profiled breakdown time stats
+        for (AggregationTimingType breakdownTimingType : AggregationTimingType.values()) {
+            buildBreakdownMap(profileResultsAcrossSlices.size(), breakdown, timeStatsMap, breakdownTimingType.toString());
+        }
+
+        // Profiled breakdown total time
+        for (AggregationTimingType breakdownTimingType : AggregationTimingType.values()) {
+            String breakdownType = breakdownTimingType.toString();
+            breakdown.put(breakdownType, maxSliceEndTimeMap.get(breakdownType) - minSliceStartTimeMap.get(breakdownType));
+        }
+
+        // Profiled breakdown count stats
+        for (String breakdownCountType : breakdownCountStatsTypes) {
+            buildBreakdownMap(profileResultsAcrossSlices.size(), breakdown, countStatsMap, breakdownCountType);
+        }
+
+        // children
+        List<ProfileResult> reducedChildrenTree = new LinkedList<>();
+        if (!children.isEmpty()) {
+            Map<String, List<ProfileResult>> sliceLevelAggregationMap = getSliceLevelAggregationMap(children);
+            for (List<ProfileResult> profileResults : sliceLevelAggregationMap.values()) {
+                reducedChildrenTree.addAll(reduceProfileResultsTree(profileResults));
+            }
+        }
+
+        ProfileResult reducedResult = new ProfileResult(
+            type,
+            description,
+            breakdown,
+            debug,
+            nodeTime,
+            reducedChildrenTree,
+            maxSliceNodeTime,
+            minSliceNodeTime,
+            avgSliceNodeTime
+        );
+        return List.of(reducedResult);
+    }
+
+    static void buildBreakdownMap(int treeSize, Map<String, Long> breakdown, Map<String, Long> statsMap, String breakdownType) {
+        String maxBreakdownType = MAX_PREFIX + breakdownType;
+        String minBreakdownType = MIN_PREFIX + breakdownType;
+        String avgBreakdownType = AVG_PREFIX + breakdownType;
+        breakdown.put(maxBreakdownType, statsMap.get(maxBreakdownType));
+        breakdown.put(minBreakdownType, statsMap.get(minBreakdownType));
+        breakdown.put(avgBreakdownType, statsMap.get(avgBreakdownType) / treeSize);
+    }
+
+    static void buildBreakdownStatsMap(Map<String, Long> statsMap, ProfileResult result, String breakdownType) {
+        String maxBreakdownType = MAX_PREFIX + breakdownType;
+        String minBreakdownType = MIN_PREFIX + breakdownType;
+        String avgBreakdownType = AVG_PREFIX + breakdownType;
+        statsMap.put(
+            maxBreakdownType,
+            Math.max(statsMap.getOrDefault(maxBreakdownType, Long.MIN_VALUE), result.getTimeBreakdown().get(breakdownType))
+        );
+        statsMap.put(
+            minBreakdownType,
+            Math.min(statsMap.getOrDefault(minBreakdownType, Long.MAX_VALUE), result.getTimeBreakdown().get(breakdownType))
+        );
+        statsMap.put(avgBreakdownType, statsMap.getOrDefault(avgBreakdownType, 0L) + result.getTimeBreakdown().get(breakdownType));
+    }
+
+    /**
+     * @return a slice level aggregation map where the key is the description of the aggregation and
+     * the value is a list of ProfileResult across all slices.
+     */
+    static Map<String, List<ProfileResult>> getSliceLevelAggregationMap(List<ProfileResult> tree) {
+        Map<String, List<ProfileResult>> sliceLevelAggregationMap = new HashMap<>();
+        for (ProfileResult result : tree) {
+            String description = result.getLuceneDescription();
+            final List<ProfileResult> sliceLevelAggregationList = sliceLevelAggregationMap.computeIfAbsent(
+                description,
+                k -> new LinkedList<>()
+            );
+            sliceLevelAggregationList.add(result);
+        }
+        return sliceLevelAggregationMap;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/InternalAggregationProfileTree.java b/server/src/main/java/org/opensearch/search/profile/aggregation/InternalAggregationProfileTree.java
index 026d1aeaf9644..34716b87c7c9c 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/InternalAggregationProfileTree.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/InternalAggregationProfileTree.java
@@ -35,6 +35,11 @@
 import org.opensearch.search.aggregations.Aggregator;
 import org.opensearch.search.profile.AbstractInternalProfileTree;
 
+/**
+ * The profiling tree for different levels of agg profiling
+ *
+ * @opensearch.internal
+ */
 public class InternalAggregationProfileTree extends AbstractInternalProfileTree<AggregationProfileBreakdown, Aggregator> {
 
     @Override
@@ -57,6 +62,10 @@ protected String getTypeFromElement(Aggregator element) {
         return element.getClass().getSimpleName();
     }
 
+    /**
+     * @return is used to group aggregations with same name across slices.
+     * So the name returned here should be same across slices for an aggregation operator.
+     */
     @Override
     protected String getDescriptionFromElement(Aggregator element) {
         return element.name();
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingAggregator.java b/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingAggregator.java
index 8d1cebebf3d33..a07dba125d67e 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingAggregator.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingAggregator.java
@@ -45,6 +45,9 @@
 import java.io.IOException;
 import java.util.Iterator;
 
+/**
+ * An aggregator that aggregates the performance profiling of other aggregations
+ */
 public class ProfilingAggregator extends Aggregator {
 
     private final Aggregator delegate;
diff --git a/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingLeafBucketCollector.java b/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingLeafBucketCollector.java
index 17e451c09a5d4..56c79465c4575 100644
--- a/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingLeafBucketCollector.java
+++ b/server/src/main/java/org/opensearch/search/profile/aggregation/ProfilingLeafBucketCollector.java
@@ -38,6 +38,11 @@
 
 import java.io.IOException;
 
+/**
+ * The collector for the agg profiles
+ *
+ * @opensearch.internal
+ */
 public class ProfilingLeafBucketCollector extends LeafBucketCollector {
 
     private LeafBucketCollector delegate;
diff --git a/server/src/main/java/org/opensearch/search/profile/query/CollectorResult.java b/server/src/main/java/org/opensearch/search/profile/query/CollectorResult.java
index 1366bfd79abc9..59d35ddd1a8d0 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/CollectorResult.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/CollectorResult.java
@@ -32,27 +32,30 @@
 
 package org.opensearch.search.profile.query;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.Version;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Public interface and serialization container for profiled timings of the
  * Collectors used in the search.  Children CollectorResult's may be
  * embedded inside of a parent CollectorResult
+ *
+ * @opensearch.internal
  */
 public class CollectorResult implements ToXContentObject, Writeable {
 
@@ -64,11 +67,17 @@ public class CollectorResult implements ToXContentObject, Writeable {
     public static final String REASON_SEARCH_MULTI = "search_multi";
     public static final String REASON_AGGREGATION = "aggregation";
     public static final String REASON_AGGREGATION_GLOBAL = "aggregation_global";
+    public static final String COLLECTOR_MANAGER = "CollectorManager";
 
     private static final ParseField NAME = new ParseField("name");
     private static final ParseField REASON = new ParseField("reason");
     private static final ParseField TIME = new ParseField("time");
     private static final ParseField TIME_NANOS = new ParseField("time_in_nanos");
+    private static final ParseField REDUCE_TIME_NANOS = new ParseField("reduce_time_in_nanos");
+    private static final ParseField MAX_SLICE_TIME_NANOS = new ParseField("max_slice_time_in_nanos");
+    private static final ParseField MIN_SLICE_TIME_IN_NANOS = new ParseField("min_slice_time_in_nanos");
+    private static final ParseField AVG_SLICE_TIME_IN_NANOS = new ParseField("avg_slice_time_in_nanos");
+    private static final ParseField SLICE_COUNT = new ParseField("slice_count");
     private static final ParseField CHILDREN = new ParseField("children");
 
     /**
@@ -84,17 +93,61 @@ public class CollectorResult implements ToXContentObject, Writeable {
     /**
      * The total elapsed time for this Collector
      */
-    private final Long time;
+    private final long time;
+
+    /**
+     * The total elapsed time in reduce phase for this CollectorManager
+     */
+    private final long reduceTime;
+
+    /**
+     * The maximum slice time for this CollectorManager
+     */
+    private final long maxSliceTime;
+
+    /**
+     * The minimum slice time for this CollectorManager
+     */
+    private final long minSliceTime;
+
+    /**
+     * The average slice time for this CollectorManager
+     */
+    private final long avgSliceTime;
+
+    /**
+     * The segment slice count for this CollectorManager
+     */
+    private final int sliceCount;
 
     /**
      * A list of children collectors "embedded" inside this collector
      */
     private List<CollectorResult> children;
 
-    public CollectorResult(String collectorName, String reason, Long time, List<CollectorResult> children) {
+    public CollectorResult(String collectorName, String reason, long time, List<CollectorResult> children) {
+        this(collectorName, reason, time, 0L, time, time, time, 1, children);
+    }
+
+    public CollectorResult(
+        String collectorName,
+        String reason,
+        long time,
+        long reduceTime,
+        long maxSliceTime,
+        long minSliceTime,
+        long avgSliceTime,
+        int sliceCount,
+        List<CollectorResult> children
+    ) {
         this.collectorName = collectorName;
         this.reason = reason;
         this.time = time;
+        this.reduceTime = reduceTime;
+        this.maxSliceTime = maxSliceTime;
+        this.minSliceTime = minSliceTime;
+        this.avgSliceTime = avgSliceTime;
+        this.sliceCount = sliceCount;
         this.children = children;
     }
 
@@ -111,6 +164,19 @@ public CollectorResult(StreamInput in) throws IOException {
             CollectorResult child = new CollectorResult(in);
             this.children.add(child);
         }
+        if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+            this.reduceTime = in.readLong();
+            this.maxSliceTime = in.readLong();
+            this.minSliceTime = in.readLong();
+            this.avgSliceTime = in.readLong();
+            this.sliceCount = in.readVInt();
+        } else {
+            this.reduceTime = 0L;
+            this.maxSliceTime = this.time;
+            this.minSliceTime = this.time;
+            this.avgSliceTime = this.time;
+            this.sliceCount = 1;
+        }
     }
 
     @Override
@@ -122,31 +188,73 @@ public void writeTo(StreamOutput out) throws IOException {
         for (CollectorResult child : children) {
             child.writeTo(out);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+            out.writeLong(reduceTime);
+            out.writeLong(maxSliceTime);
+            out.writeLong(minSliceTime);
+            out.writeLong(avgSliceTime);
+            out.writeVInt(sliceCount);
+        }
     }
 
     /**
-     * @return the profiled time for this collector (inclusive of children)
+     * @return the profiled time for this collector/collector manager (inclusive of children)
      */
     public long getTime() {
         return this.time;
     }
 
     /**
-     * @return a human readable "hint" about what this collector was used for
+     * @return the profiled reduce time for this collector manager (inclusive of children)
+     */
+    public long getReduceTime() {
+        return this.reduceTime;
+    }
+
+    /**
+     * @return the profiled maximum slice time for this collector manager (inclusive of children)
+     */
+    public long getMaxSliceTime() {
+        return this.maxSliceTime;
+    }
+
+    /**
+     * @return the profiled minimum slice time for this collector manager (inclusive of children)
+     */
+    public long getMinSliceTime() {
+        return this.minSliceTime;
+    }
+
+    /**
+     * @return the profiled average slice time for this collector manager (inclusive of children)
+     */
+    public long getAvgSliceTime() {
+        return this.avgSliceTime;
+    }
+
+    /**
+     * @return the profiled segment slice count for this collector manager (inclusive of children)
+     */
+    public int getSliceCount() {
+        return this.sliceCount;
+    }
+
+    /**
+     * @return a human readable "hint" about what this collector/collector manager was used for
      */
     public String getReason() {
         return this.reason;
     }
 
     /**
-     * @return the lucene class name of the collector
+     * @return the lucene class name of the collector/collector manager
      */
     public String getName() {
         return this.collectorName;
     }
 
     /**
-     * @return a list of children collectors
+     * @return a list of children collectors/collector managers
      */
     public List<CollectorResult> getProfiledChildren() {
         return children;
@@ -161,6 +269,13 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
             builder.field(TIME.getPreferredName(), new TimeValue(getTime(), TimeUnit.NANOSECONDS).toString());
         }
         builder.field(TIME_NANOS.getPreferredName(), getTime());
+        if (getName().contains(COLLECTOR_MANAGER)) {
+            builder.field(REDUCE_TIME_NANOS.getPreferredName(), getReduceTime());
+            builder.field(MAX_SLICE_TIME_NANOS.getPreferredName(), getMaxSliceTime());
+            builder.field(MIN_SLICE_TIME_IN_NANOS.getPreferredName(), getMinSliceTime());
+            builder.field(AVG_SLICE_TIME_IN_NANOS.getPreferredName(), getAvgSliceTime());
+            builder.field(SLICE_COUNT.getPreferredName(), getSliceCount());
+        }
 
         if (!children.isEmpty()) {
             builder = builder.startArray(CHILDREN.getPreferredName());
@@ -179,6 +294,11 @@ public static CollectorResult fromXContent(XContentParser parser) throws IOExcep
         String currentFieldName = null;
         String name = null, reason = null;
         long time = -1;
+        long reduceTime = -1;
+        long maxSliceTime = -1;
+        long minSliceTime = -1;
+        long avgSliceTime = -1;
+        int sliceCount = 0;
         List<CollectorResult> children = new ArrayList<>();
         while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
             if (token == XContentParser.Token.FIELD_NAME) {
@@ -193,6 +313,16 @@ public static CollectorResult fromXContent(XContentParser parser) throws IOExcep
                     parser.text();
                 } else if (TIME_NANOS.match(currentFieldName, parser.getDeprecationHandler())) {
                     time = parser.longValue();
+                } else if (REDUCE_TIME_NANOS.match(currentFieldName, parser.getDeprecationHandler())) {
+                    reduceTime = parser.longValue();
+                } else if (MAX_SLICE_TIME_NANOS.match(currentFieldName, parser.getDeprecationHandler())) {
+                    maxSliceTime = parser.longValue();
+                } else if (MIN_SLICE_TIME_IN_NANOS.match(currentFieldName, parser.getDeprecationHandler())) {
+                    minSliceTime = parser.longValue();
+                } else if (AVG_SLICE_TIME_IN_NANOS.match(currentFieldName, parser.getDeprecationHandler())) {
+                    avgSliceTime = parser.longValue();
+                } else if (SLICE_COUNT.match(currentFieldName, parser.getDeprecationHandler())) {
+                    sliceCount = parser.intValue();
                 } else {
                     parser.skipChildren();
                 }
@@ -208,6 +338,6 @@ public static CollectorResult fromXContent(XContentParser parser) throws IOExcep
                 parser.skipChildren();
             }
         }
-        return new CollectorResult(name, reason, time, children);
+        return new CollectorResult(name, reason, time, reduceTime, maxSliceTime, minSliceTime, avgSliceTime, sliceCount, children);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/profile/query/ConcurrentQueryProfileBreakdown.java b/server/src/main/java/org/opensearch/search/profile/query/ConcurrentQueryProfileBreakdown.java
index 08f43e72d73dc..6f0c78e8b307d 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/ConcurrentQueryProfileBreakdown.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/ConcurrentQueryProfileBreakdown.java
@@ -19,6 +19,8 @@
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc). The class supports profiling the concurrent search over segments.
+ *
+ * @opensearch.internal
  */
 public final class ConcurrentQueryProfileBreakdown extends ContextualProfileBreakdown<QueryTimingType> {
     private final Map<Object, AbstractProfileBreakdown<QueryTimingType>> contexts = new ConcurrentHashMap<>();
@@ -42,10 +44,10 @@ public AbstractProfileBreakdown<QueryTimingType> context(Object context) {
 
     @Override
     public Map<String, Long> toBreakdownMap() {
-        final Map<String, Long> map = new HashMap<>(buildBreakdownMap(this));
+        final Map<String, Long> map = new HashMap<>(super.toBreakdownMap());
 
         for (final AbstractProfileBreakdown<QueryTimingType> context : contexts.values()) {
-            for (final Map.Entry<String, Long> entry : buildBreakdownMap(context).entrySet()) {
+            for (final Map.Entry<String, Long> entry : context.toBreakdownMap().entrySet()) {
                 map.merge(entry.getKey(), entry.getValue(), Long::sum);
             }
         }
diff --git a/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollector.java b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollector.java
index d6ada27cbf65f..8b860c3a58cea 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollector.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollector.java
@@ -50,6 +50,8 @@
  * - needsScores()
  *
  * InternalProfiler facilitates the linking of the Collector graph
+ *
+ * @opensearch.internal
  */
 public class InternalProfileCollector implements Collector, InternalProfileComponent {
 
@@ -85,6 +87,13 @@ public long getTime() {
         return collector.getTime();
     }
 
+    /**
+     * @return the profiled start time for this collector (inclusive of children)
+     */
+    public long getSliceStartTime() {
+        return collector.getSliceStartTime();
+    }
+
     /**
      * @return a human readable "hint" about what this collector was used for
      */
diff --git a/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollectorManager.java b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollectorManager.java
new file mode 100644
index 0000000000000..4156e442c9254
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileCollectorManager.java
@@ -0,0 +1,175 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.profile.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.search.aggregations.AggregationCollectorManager;
+import org.opensearch.search.query.EarlyTerminatingListener;
+import org.opensearch.search.query.ReduceableSearchResult;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Collector Manager for internal agg profiling
+ *
+ * @opensearch.internal
+ */
+public class InternalProfileCollectorManager
+    implements
+        ProfileCollectorManager<InternalProfileCollector, ReduceableSearchResult>,
+        EarlyTerminatingListener {
+    private final CollectorManager<? extends Collector, ReduceableSearchResult> manager;
+    private final String reason;
+    private final List<InternalProfileCollectorManager> children;
+    private long time = 0;
+    private long reduceTime = 0;
+    private long maxSliceEndTime = Long.MIN_VALUE;
+    private long minSliceStartTime = Long.MAX_VALUE;
+    private long maxSliceTime = 0;
+    private long minSliceTime = Long.MAX_VALUE;
+    private long avgSliceTime = 0;
+    private int sliceCount = 0;
+    private String collectorManagerName;
+
+    public InternalProfileCollectorManager(
+        CollectorManager<? extends Collector, ReduceableSearchResult> manager,
+        String reason,
+        List<InternalProfileCollectorManager> children
+    ) {
+        this.manager = manager;
+        this.reason = reason;
+        this.collectorManagerName = deriveCollectorManagerName(manager);
+        this.children = children;
+    }
+
+    /**
+     * Creates a human-friendly representation of the CollectorManager name.
+     *
+     * @param manager The CollectorManager to derive a name from
+     * @return  A (hopefully) prettier name
+     */
+    private String deriveCollectorManagerName(CollectorManager<? extends Collector, ReduceableSearchResult> manager) {
+        String name = manager.getClass().getSimpleName();
+        if (name.equals("")) {
+            name = manager.getClass().getEnclosingClass().getSimpleName();
+        }
+
+        // Include the user-defined agg name
+        if (manager instanceof AggregationCollectorManager) {
+            name += ": [" + ((AggregationCollectorManager) manager).getCollectorName() + "]";
+        }
+        return name;
+    }
+
+    @Override
+    public InternalProfileCollector newCollector() throws IOException {
+        return new InternalProfileCollector(manager.newCollector(), reason, children);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public ReduceableSearchResult reduce(Collection<InternalProfileCollector> collectors) throws IOException {
+        final long reduceStart = System.nanoTime();
+        try {
+            final Collection<Collector> subs = new ArrayList<>();
+
+            for (final InternalProfileCollector collector : collectors) {
+                subs.add(collector.getCollector());
+                maxSliceEndTime = Math.max(maxSliceEndTime, collector.getSliceStartTime() + collector.getTime());
+                minSliceStartTime = Math.min(minSliceStartTime, collector.getSliceStartTime());
+                maxSliceTime = Math.max(maxSliceTime, collector.getTime());
+                minSliceTime = Math.min(minSliceTime, collector.getTime());
+                avgSliceTime += collector.getTime();
+            }
+            time = maxSliceEndTime - minSliceStartTime;
+            sliceCount = collectors.size();
+            avgSliceTime = sliceCount == 0 ? 0 : avgSliceTime / sliceCount;
+
+            return ((CollectorManager<Collector, ReduceableSearchResult>) manager).reduce(subs);
+        } finally {
+            reduceTime = Math.max(1, System.nanoTime() - reduceStart);
+        }
+
+    }
+
+    @Override
+    public String getReason() {
+        return reason;
+    }
+
+    @Override
+    public long getTime() {
+        return time;
+    }
+
+    public long getReduceTime() {
+        return reduceTime;
+    }
+
+    public long getMaxSliceTime() {
+        return maxSliceTime;
+    }
+
+    public long getMinSliceTime() {
+        return minSliceTime;
+    }
+
+    public long getAvgSliceTime() {
+        return avgSliceTime;
+    }
+
+    public int getSliceCount() {
+        return sliceCount;
+    }
+
+    @Override
+    public Collection<? extends InternalProfileComponent> children() {
+        return children;
+    }
+
+    @Override
+    public String getName() {
+        return collectorManagerName;
+    }
+
+    @Override
+    public CollectorResult getCollectorTree() {
+        return doGetCollectorManagerTree(this);
+    }
+
+    static CollectorResult doGetCollectorManagerTree(InternalProfileCollectorManager collector) {
+        List<CollectorResult> childResults = new ArrayList<>(collector.children().size());
+        for (InternalProfileComponent child : collector.children()) {
+            CollectorResult result = doGetCollectorManagerTree((InternalProfileCollectorManager) child);
+            childResults.add(result);
+        }
+        return new CollectorResult(
+            collector.getName(),
+            collector.getReason(),
+            collector.getTime(),
+            collector.getReduceTime(),
+            collector.getMaxSliceTime(),
+            collector.getMinSliceTime(),
+            collector.getAvgSliceTime(),
+            collector.getSliceCount(),
+            childResults
+        );
+    }
+
+    @Override
+    public void onEarlyTermination(int maxCountHits, boolean forcedTermination) {
+        if (manager instanceof EarlyTerminatingListener) {
+            ((EarlyTerminatingListener) manager).onEarlyTermination(maxCountHits, forcedTermination);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/profile/query/InternalProfileComponent.java b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileComponent.java
index 9d0d32960a817..1752d76e27f06 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/InternalProfileComponent.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/InternalProfileComponent.java
@@ -10,6 +10,11 @@
 
 import java.util.Collection;
 
+/**
+ * Container for an agg profiling component
+ *
+ * @opensearch.internal
+ */
 public interface InternalProfileComponent {
     /**
      * @return profile component name
diff --git a/server/src/main/java/org/opensearch/search/profile/query/InternalQueryProfileTree.java b/server/src/main/java/org/opensearch/search/profile/query/InternalQueryProfileTree.java
index e72f70300e092..40c6a29384491 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/InternalQueryProfileTree.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/InternalQueryProfileTree.java
@@ -41,6 +41,8 @@
  * This class tracks the dependency tree for queries (scoring and rewriting) and
  * generates {@link QueryProfileBreakdown} for each node in the tree.  It also finalizes the tree
  * and returns a list of {@link ProfileResult} that can be serialized back to the client
+ *
+ * @opensearch.internal
  */
 final class InternalQueryProfileTree extends AbstractInternalProfileTree<ContextualProfileBreakdown<QueryTimingType>, Query> {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/ProfileCollector.java b/server/src/main/java/org/opensearch/search/profile/query/ProfileCollector.java
index 299beb01aacee..198b1586a7c58 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/ProfileCollector.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/ProfileCollector.java
@@ -42,10 +42,16 @@
 
 import java.io.IOException;
 
-/** A collector that profiles how much time is spent calling it. */
+/**
+ * A collector that profiles how much time is spent calling it.
+ *
+ * @opensearch.internal
+ */
 final class ProfileCollector extends FilterCollector {
 
     private long time;
+    private long sliceStartTime;
+    private boolean isStarted;
 
     /** Sole constructor. */
     ProfileCollector(Collector in) {
@@ -63,6 +69,10 @@ public ScoreMode scoreMode() {
         try {
             return super.scoreMode();
         } finally {
+            if (isStarted == false) {
+                sliceStartTime = start;
+                isStarted = true;
+            }
             time += Math.max(1, System.nanoTime() - start);
         }
     }
@@ -74,6 +84,10 @@ public LeafCollector getLeafCollector(LeafReaderContext context) throws IOExcept
         try {
             inLeafCollector = super.getLeafCollector(context);
         } finally {
+            if (isStarted == false) {
+                sliceStartTime = start;
+                isStarted = true;
+            }
             time += Math.max(1, System.nanoTime() - start);
         }
         return new FilterLeafCollector(inLeafCollector) {
@@ -105,4 +119,8 @@ public long getTime() {
         return time;
     }
 
+    /** Return the start time on this collector. */
+    public long getSliceStartTime() {
+        return sliceStartTime;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/profile/query/ProfileCollectorManager.java b/server/src/main/java/org/opensearch/search/profile/query/ProfileCollectorManager.java
new file mode 100644
index 0000000000000..5a8566e6dfa71
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/profile/query/ProfileCollectorManager.java
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.profile.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+
+/**
+ * Collector manager which supports profiling
+ *
+ * @opensearch.internal
+ */
+public interface ProfileCollectorManager<C extends Collector, T> extends CollectorManager<C, T>, InternalProfileComponent {}
diff --git a/server/src/main/java/org/opensearch/search/profile/query/ProfileScorer.java b/server/src/main/java/org/opensearch/search/profile/query/ProfileScorer.java
index 3c0ddee7cfcb5..319281449195b 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/ProfileScorer.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/ProfileScorer.java
@@ -45,6 +45,8 @@
 /**
  * {@link Scorer} wrapper that will compute how much time is spent on moving
  * the iterator, confirming matches and computing scores.
+ *
+ * @opensearch.internal
  */
 final class ProfileScorer extends Scorer {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/ProfileWeight.java b/server/src/main/java/org/opensearch/search/profile/query/ProfileWeight.java
index 56b69ab3fb265..12f9a7184d84a 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/ProfileWeight.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/ProfileWeight.java
@@ -48,6 +48,8 @@
  * Weight wrapper that will compute how much time it takes to build the
  * {@link Scorer} and then return a {@link Scorer} that is wrapped in
  * order to compute timings as well.
+ *
+ * @opensearch.internal
  */
 public final class ProfileWeight extends Weight {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/QueryProfileBreakdown.java b/server/src/main/java/org/opensearch/search/profile/query/QueryProfileBreakdown.java
index 3e0ee8db4df56..3514a80e39d85 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/QueryProfileBreakdown.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/QueryProfileBreakdown.java
@@ -39,6 +39,8 @@
  * A record of timings for the various operations that may happen during query execution.
  * A node's time may be composed of several internal attributes (rewriting, weighting,
  * scoring, etc).
+ *
+ * @opensearch.internal
  */
 public final class QueryProfileBreakdown extends ContextualProfileBreakdown<QueryTimingType> {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/QueryProfileShardResult.java b/server/src/main/java/org/opensearch/search/profile/query/QueryProfileShardResult.java
index 283adddaba5b7..a9f3d4aaf7885 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/QueryProfileShardResult.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/QueryProfileShardResult.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.profile.query;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.profile.ProfileResult;
 
 import java.io.IOException;
@@ -45,11 +45,13 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * A container class to hold the profile results for a single shard in the request.
  * Contains a list of query profiles, a collector tree and a total rewrite tree.
+ *
+ * @opensearch.internal
  */
 public final class QueryProfileShardResult implements Writeable, ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/QueryProfiler.java b/server/src/main/java/org/opensearch/search/profile/query/QueryProfiler.java
index e78347713353c..9527e010005c3 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/QueryProfiler.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/QueryProfiler.java
@@ -48,6 +48,8 @@
  * A Profiler is associated with every Search, not per Search-Request. E.g. a
  * request may execute two searches (query + global agg).  A Profiler just
  * represents one of those
+ *
+ * @opensearch.internal
  */
 public final class QueryProfiler extends AbstractProfiler<ContextualProfileBreakdown<QueryTimingType>, Query> {
 
diff --git a/server/src/main/java/org/opensearch/search/profile/query/QueryTimingType.java b/server/src/main/java/org/opensearch/search/profile/query/QueryTimingType.java
index 7748b76cb1611..0cc7d1315ad61 100644
--- a/server/src/main/java/org/opensearch/search/profile/query/QueryTimingType.java
+++ b/server/src/main/java/org/opensearch/search/profile/query/QueryTimingType.java
@@ -34,6 +34,11 @@
 
 import java.util.Locale;
 
+/**
+ * Different profile levels of the query
+ *
+ * @opensearch.internal
+ */
 public enum QueryTimingType {
     CREATE_WEIGHT,
     BUILD_SCORER,
diff --git a/server/src/main/java/org/opensearch/search/query/ConcurrentQueryPhaseSearcher.java b/server/src/main/java/org/opensearch/search/query/ConcurrentQueryPhaseSearcher.java
new file mode 100644
index 0000000000000..e22f766d3894c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/ConcurrentQueryPhaseSearcher.java
@@ -0,0 +1,127 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.Query;
+import org.opensearch.OpenSearchException;
+import org.opensearch.search.aggregations.AggregationProcessor;
+import org.opensearch.search.aggregations.ConcurrentAggregationProcessor;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.query.ProfileCollectorManager;
+import org.opensearch.search.query.QueryPhase.DefaultQueryPhaseSearcher;
+
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.search.query.TopDocsCollectorContext.createTopDocsCollectorContext;
+
+/**
+ * The implementation of the {@link QueryPhaseSearcher} which attempts to use concurrent
+ * search of Apache Lucene segments if it has been enabled.
+ */
+public class ConcurrentQueryPhaseSearcher extends DefaultQueryPhaseSearcher {
+    private static final Logger LOGGER = LogManager.getLogger(ConcurrentQueryPhaseSearcher.class);
+    private final AggregationProcessor aggregationProcessor = new ConcurrentAggregationProcessor();
+
+    /**
+     * Default constructor
+     */
+    public ConcurrentQueryPhaseSearcher() {}
+
+    @Override
+    protected boolean searchWithCollector(
+        SearchContext searchContext,
+        ContextIndexSearcher searcher,
+        Query query,
+        LinkedList<QueryCollectorContext> collectors,
+        boolean hasFilterCollector,
+        boolean hasTimeout
+    ) throws IOException {
+        return searchWithCollectorManager(searchContext, searcher, query, collectors, hasFilterCollector, hasTimeout);
+    }
+
+    private static boolean searchWithCollectorManager(
+        SearchContext searchContext,
+        ContextIndexSearcher searcher,
+        Query query,
+        LinkedList<QueryCollectorContext> collectorContexts,
+        boolean hasFilterCollector,
+        boolean timeoutSet
+    ) throws IOException {
+        // create the top docs collector last when the other collectors are known
+        final TopDocsCollectorContext topDocsFactory = createTopDocsCollectorContext(searchContext, hasFilterCollector);
+        // add the top docs collector, the first collector context in the chain
+        collectorContexts.addFirst(topDocsFactory);
+
+        final QuerySearchResult queryResult = searchContext.queryResult();
+        final CollectorManager<?, ReduceableSearchResult> collectorManager;
+
+        if (searchContext.getProfilers() != null) {
+            final ProfileCollectorManager<? extends Collector, ReduceableSearchResult> profileCollectorManager =
+                QueryCollectorManagerContext.createQueryCollectorManagerWithProfiler(collectorContexts);
+            searchContext.getProfilers().getCurrentQueryProfiler().setCollector(profileCollectorManager);
+            collectorManager = profileCollectorManager;
+        } else {
+            // Create collector manager tree
+            collectorManager = QueryCollectorManagerContext.createQueryCollectorManager(collectorContexts);
+        }
+
+        try {
+            final ReduceableSearchResult result = searcher.search(query, collectorManager);
+            result.reduce(queryResult);
+        } catch (RuntimeException re) {
+            rethrowCauseIfPossible(re, searchContext);
+        }
+        if (searchContext.isSearchTimedOut()) {
+            assert timeoutSet : "TimeExceededException thrown even though timeout wasn't set";
+            if (searchContext.request().allowPartialSearchResults() == false) {
+                throw new QueryPhaseExecutionException(searchContext.shardTarget(), "Time exceeded");
+            }
+            queryResult.searchTimedOut(true);
+        }
+        if (searchContext.terminateAfter() != SearchContext.DEFAULT_TERMINATE_AFTER && queryResult.terminatedEarly() == null) {
+            queryResult.terminatedEarly(false);
+        }
+
+        return topDocsFactory.shouldRescore();
+    }
+
+    @Override
+    public AggregationProcessor aggregationProcessor(SearchContext searchContext) {
+        return aggregationProcessor;
+    }
+
+    private static <T extends Exception> void rethrowCauseIfPossible(RuntimeException re, SearchContext searchContext) throws T {
+        // Rethrow exception if cause is null or if it's an instance of OpenSearchException
+        if (re.getCause() == null || re instanceof OpenSearchException) {
+            throw re;
+        }
+
+        // Unwrap the RuntimeException and ExecutionException from Lucene concurrent search method and rethrow
+        if (re.getCause() instanceof ExecutionException || re.getCause() instanceof InterruptedException) {
+            Throwable t = re.getCause();
+            if (t.getCause() != null) {
+                throw (T) t.getCause();
+            }
+        }
+
+        // Rethrow any unexpected exception types
+        throw new QueryPhaseExecutionException(
+            searchContext.shardTarget(),
+            "Failed to execute concurrent segment search thread",
+            re.getCause()
+        );
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollector.java b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollector.java
index 3ee8430522891..5b86a70d64fff 100644
--- a/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollector.java
+++ b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollector.java
@@ -43,6 +43,8 @@
 
 /**
  * A {@link Collector} that early terminates collection after <code>maxCountHits</code> docs have been collected.
+ *
+ * @opensearch.internal
  */
 public class EarlyTerminatingCollector extends FilterCollector {
     static final class EarlyTerminationException extends RuntimeException {
@@ -95,6 +97,10 @@ public void collect(int doc) throws IOException {
         };
     }
 
+    Collector getCollector() {
+        return in;
+    }
+
     /**
      * Returns true if this collector has early terminated.
      */
diff --git a/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollectorManager.java b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollectorManager.java
new file mode 100644
index 0000000000000..e8153fd384b5d
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingCollectorManager.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Manager for the EarlyTerminatingCollector
+ *
+ * @opensearch.internal
+ */
+public class EarlyTerminatingCollectorManager<C extends Collector>
+    implements
+        CollectorManager<EarlyTerminatingCollector, ReduceableSearchResult>,
+        EarlyTerminatingListener {
+
+    private final CollectorManager<C, ReduceableSearchResult> manager;
+    private final int maxCountHits;
+    private boolean forceTermination;
+
+    EarlyTerminatingCollectorManager(CollectorManager<C, ReduceableSearchResult> manager, int maxCountHits, boolean forceTermination) {
+        this.manager = manager;
+        this.maxCountHits = maxCountHits;
+        this.forceTermination = forceTermination;
+    }
+
+    @Override
+    public EarlyTerminatingCollector newCollector() throws IOException {
+        return new EarlyTerminatingCollector(manager.newCollector(), maxCountHits, false /* forced termination is not supported */);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public ReduceableSearchResult reduce(Collection<EarlyTerminatingCollector> collectors) throws IOException {
+        final List<C> innerCollectors = new ArrayList<>(collectors.size());
+
+        boolean didTerminateEarly = false;
+        for (EarlyTerminatingCollector collector : collectors) {
+            innerCollectors.add((C) collector.getCollector());
+            if (collector.hasEarlyTerminated()) {
+                didTerminateEarly = true;
+            }
+        }
+
+        if (didTerminateEarly) {
+            onEarlyTermination(maxCountHits, forceTermination);
+
+            final ReduceableSearchResult result = manager.reduce(innerCollectors);
+            return new ReduceableSearchResult() {
+                @Override
+                public void reduce(QuerySearchResult r) throws IOException {
+                    result.reduce(r);
+                    r.terminatedEarly(true);
+                }
+            };
+        }
+
+        return manager.reduce(innerCollectors);
+    }
+
+    @Override
+    public void onEarlyTermination(int maxCountHits, boolean forcedTermination) {
+        if (manager instanceof EarlyTerminatingListener) {
+            ((EarlyTerminatingListener) manager).onEarlyTermination(maxCountHits, forcedTermination);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/EarlyTerminatingListener.java b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingListener.java
new file mode 100644
index 0000000000000..340fb26923cf7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/EarlyTerminatingListener.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+/**
+ * Early termination event listener. It is used during concurrent segment search
+ * to propagate the early termination intent.
+ *
+ * @opensearch.internal
+ */
+public interface EarlyTerminatingListener {
+    /**
+     * Early termination event notification
+     * @param maxCountHits desired maximum number of hits
+     * @param forcedTermination :true" if forced termination has been requested, "false" otherwise
+     */
+    void onEarlyTermination(int maxCountHits, boolean forcedTermination);
+}
diff --git a/server/src/main/java/org/opensearch/search/query/FilteredCollectorManager.java b/server/src/main/java/org/opensearch/search/query/FilteredCollectorManager.java
new file mode 100644
index 0000000000000..96f449daf912e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/FilteredCollectorManager.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.Weight;
+import org.opensearch.common.lucene.search.FilteredCollector;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+
+/**
+ * Manager for the FilteredCollector
+ *
+ * @opensearch.internal
+ */
+class FilteredCollectorManager implements CollectorManager<FilteredCollector, ReduceableSearchResult> {
+    private final CollectorManager<? extends Collector, ReduceableSearchResult> manager;
+    private final Weight filter;
+
+    FilteredCollectorManager(CollectorManager<? extends Collector, ReduceableSearchResult> manager, Weight filter) {
+        this.manager = manager;
+        this.filter = filter;
+    }
+
+    @Override
+    public FilteredCollector newCollector() throws IOException {
+        return new FilteredCollector(manager.newCollector(), filter);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public ReduceableSearchResult reduce(Collection<FilteredCollector> collectors) throws IOException {
+        final Collection<Collector> subCollectors = new ArrayList<>();
+
+        for (final FilteredCollector collector : collectors) {
+            subCollectors.add(collector.getCollector());
+        }
+
+        return ((CollectorManager<Collector, ReduceableSearchResult>) manager).reduce(subCollectors);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/MinimumCollectorManager.java b/server/src/main/java/org/opensearch/search/query/MinimumCollectorManager.java
new file mode 100644
index 0000000000000..ed99f3dd8cc5c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/MinimumCollectorManager.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.opensearch.common.lucene.MinimumScoreCollector;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+
+/**
+ * Manager for the MinimumCollector
+ */
+class MinimumCollectorManager implements CollectorManager<MinimumScoreCollector, ReduceableSearchResult> {
+    private final CollectorManager<? extends Collector, ReduceableSearchResult> manager;
+    private final float minimumScore;
+
+    MinimumCollectorManager(CollectorManager<? extends Collector, ReduceableSearchResult> manager, float minimumScore) {
+        this.manager = manager;
+        this.minimumScore = minimumScore;
+    }
+
+    @Override
+    public MinimumScoreCollector newCollector() throws IOException {
+        return new MinimumScoreCollector(manager.newCollector(), minimumScore);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public ReduceableSearchResult reduce(Collection<MinimumScoreCollector> collectors) throws IOException {
+        final Collection<Collector> subCollectors = new ArrayList<>();
+
+        for (final MinimumScoreCollector collector : collectors) {
+            subCollectors.add(collector.getCollector());
+        }
+
+        return ((CollectorManager<Collector, ReduceableSearchResult>) manager).reduce(subCollectors);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/MultiCollectorWrapper.java b/server/src/main/java/org/opensearch/search/query/MultiCollectorWrapper.java
new file mode 100644
index 0000000000000..7c57193349b91
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/MultiCollectorWrapper.java
@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.LeafCollector;
+import org.apache.lucene.search.MultiCollector;
+import org.apache.lucene.search.ScoreMode;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Wraps MultiCollector and provide access to underlying collectors.
+ * Please check out https://github.com/apache/lucene/pull/455.
+ *
+ * @opensearch.internal
+ */
+public class MultiCollectorWrapper implements Collector {
+    private final MultiCollector delegate;
+    private final Collection<Collector> collectors;
+
+    MultiCollectorWrapper(MultiCollector delegate, Collection<Collector> collectors) {
+        this.delegate = delegate;
+        this.collectors = collectors;
+    }
+
+    @Override
+    public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
+        return delegate.getLeafCollector(context);
+    }
+
+    @Override
+    public ScoreMode scoreMode() {
+        return delegate.scoreMode();
+    }
+
+    public Collection<Collector> getCollectors() {
+        return collectors;
+    }
+
+    public static Collector wrap(Collector... collectors) {
+        final List<Collector> collectorsList = Arrays.asList(collectors);
+        final Collector collector = MultiCollector.wrap(collectorsList);
+        if (collector instanceof MultiCollector) {
+            return new MultiCollectorWrapper((MultiCollector) collector, collectorsList);
+        } else {
+            return collector;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/QueryCollectorContext.java b/server/src/main/java/org/opensearch/search/query/QueryCollectorContext.java
index d1ff855888f0b..10c070ea7dceb 100644
--- a/server/src/main/java/org/opensearch/search/query/QueryCollectorContext.java
+++ b/server/src/main/java/org/opensearch/search/query/QueryCollectorContext.java
@@ -33,6 +33,7 @@
 package org.opensearch.search.query;
 
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MultiCollector;
 import org.apache.lucene.search.Query;
@@ -41,7 +42,11 @@
 import org.apache.lucene.search.Weight;
 import org.opensearch.common.lucene.MinimumScoreCollector;
 import org.opensearch.common.lucene.search.FilteredCollector;
+import org.opensearch.search.aggregations.AggregationCollectorManager;
+import org.opensearch.search.aggregations.BucketCollector;
+import org.opensearch.search.profile.query.CollectorResult;
 import org.opensearch.search.profile.query.InternalProfileCollector;
+import org.opensearch.search.profile.query.InternalProfileCollectorManager;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,7 +59,12 @@
 import static org.opensearch.search.profile.query.CollectorResult.REASON_SEARCH_POST_FILTER;
 import static org.opensearch.search.profile.query.CollectorResult.REASON_SEARCH_TERMINATE_AFTER_COUNT;
 
-abstract class QueryCollectorContext {
+/**
+ * The context used during query collection
+ *
+ * @opensearch.internal
+ */
+public abstract class QueryCollectorContext {
     private static final Collector EMPTY_COLLECTOR = new SimpleCollector() {
         @Override
         public void collect(int doc) {}
@@ -77,6 +87,8 @@ public ScoreMode scoreMode() {
      */
     abstract Collector create(Collector in) throws IOException;
 
+    abstract CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException;
+
     /**
      * Wraps this collector with a profiler
      */
@@ -85,6 +97,18 @@ protected InternalProfileCollector createWithProfiler(InternalProfileCollector i
         return new InternalProfileCollector(collector, profilerName, in != null ? Collections.singletonList(in) : Collections.emptyList());
     }
 
+    /**
+     * Wraps this collector manager with a profiler
+     */
+    protected InternalProfileCollectorManager createWithProfiler(InternalProfileCollectorManager in) throws IOException {
+        final CollectorManager<? extends Collector, ReduceableSearchResult> manager = createManager(in);
+        return new InternalProfileCollectorManager(
+            manager,
+            profilerName,
+            in != null ? Collections.singletonList(in) : Collections.emptyList()
+        );
+    }
+
     /**
      * Post-process <code>result</code> after search execution.
      *
@@ -126,6 +150,11 @@ static QueryCollectorContext createMinScoreCollectorContext(float minScore) {
             Collector create(Collector in) {
                 return new MinimumScoreCollector(in, minScore);
             }
+
+            @Override
+            CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException {
+                return new MinimumCollectorManager(in, minScore);
+            }
         };
     }
 
@@ -139,35 +168,88 @@ Collector create(Collector in) throws IOException {
                 final Weight filterWeight = searcher.createWeight(searcher.rewrite(query), ScoreMode.COMPLETE_NO_SCORES, 1f);
                 return new FilteredCollector(in, filterWeight);
             }
+
+            @Override
+            CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException {
+                final Weight filterWeight = searcher.createWeight(searcher.rewrite(query), ScoreMode.COMPLETE_NO_SCORES, 1f);
+                return new FilteredCollectorManager(in, filterWeight);
+            }
         };
     }
 
     /**
-     * Creates a multi collector from the provided <code>subs</code>
+     * Creates a multi collector manager from the provided <code>subs</code>
      */
-    static QueryCollectorContext createMultiCollectorContext(Collection<Collector> subs) {
+    static QueryCollectorContext createMultiCollectorContext(
+        Collection<CollectorManager<? extends Collector, ReduceableSearchResult>> subs
+    ) {
         return new QueryCollectorContext(REASON_SEARCH_MULTI) {
             @Override
-            Collector create(Collector in) {
+            Collector create(Collector in) throws IOException {
                 List<Collector> subCollectors = new ArrayList<>();
                 subCollectors.add(in);
-                subCollectors.addAll(subs);
+                for (CollectorManager<? extends Collector, ReduceableSearchResult> manager : subs) {
+                    subCollectors.add(manager.newCollector());
+                }
                 return MultiCollector.wrap(subCollectors);
             }
 
             @Override
-            protected InternalProfileCollector createWithProfiler(InternalProfileCollector in) {
+            protected InternalProfileCollector createWithProfiler(InternalProfileCollector in) throws IOException {
                 final List<InternalProfileCollector> subCollectors = new ArrayList<>();
                 subCollectors.add(in);
-                if (subs.stream().anyMatch((col) -> col instanceof InternalProfileCollector == false)) {
-                    throw new IllegalArgumentException("non-profiling collector");
-                }
-                for (Collector collector : subs) {
-                    subCollectors.add((InternalProfileCollector) collector);
+
+                for (CollectorManager<? extends Collector, ReduceableSearchResult> manager : subs) {
+                    final Collector collector = manager.newCollector();
+                    if (collector instanceof BucketCollector) {
+                        subCollectors.add(
+                            new InternalProfileCollector(collector, CollectorResult.REASON_AGGREGATION, Collections.emptyList())
+                        );
+                    } else {
+                        subCollectors.add(
+                            new InternalProfileCollector(collector, CollectorResult.REASON_SEARCH_MULTI, Collections.emptyList())
+                        );
+                    }
                 }
+
                 final Collector collector = MultiCollector.wrap(subCollectors);
                 return new InternalProfileCollector(collector, REASON_SEARCH_MULTI, subCollectors);
             }
+
+            @Override
+            protected InternalProfileCollectorManager createWithProfiler(InternalProfileCollectorManager in) {
+                final List<CollectorManager<?, ReduceableSearchResult>> managers = new ArrayList<>();
+                final List<InternalProfileCollectorManager> children = new ArrayList<>();
+                managers.add(in);
+                children.add(in);
+                for (CollectorManager<? extends Collector, ReduceableSearchResult> manager : subs) {
+                    final InternalProfileCollectorManager subCollectorManager;
+                    if (manager instanceof AggregationCollectorManager) {
+                        subCollectorManager = new InternalProfileCollectorManager(
+                            manager,
+                            ((AggregationCollectorManager) manager).getCollectorReason(),
+                            Collections.emptyList()
+                        );
+                    } else {
+                        subCollectorManager = new InternalProfileCollectorManager(manager, REASON_SEARCH_MULTI, Collections.emptyList());
+                    }
+                    managers.add(subCollectorManager);
+                    children.add(subCollectorManager);
+                }
+                CollectorManager<? extends Collector, ReduceableSearchResult> multiCollectorManager = QueryCollectorManagerContext
+                    .createMultiCollectorManager(managers);
+                return new InternalProfileCollectorManager(multiCollectorManager, REASON_SEARCH_MULTI, children);
+            }
+
+            @Override
+            CollectorManager<? extends Collector, ReduceableSearchResult> createManager(
+                CollectorManager<? extends Collector, ReduceableSearchResult> in
+            ) throws IOException {
+                final List<CollectorManager<?, ReduceableSearchResult>> managers = new ArrayList<>();
+                managers.add(in);
+                managers.addAll(subs);
+                return QueryCollectorManagerContext.createMultiCollectorManager(managers);
+            }
         };
     }
 
@@ -192,6 +274,13 @@ Collector create(Collector in) {
                 this.collector = MultiCollector.wrap(subCollectors);
                 return collector;
             }
+
+            @Override
+            CollectorManager<? extends Collector, ReduceableSearchResult> createManager(
+                CollectorManager<? extends Collector, ReduceableSearchResult> in
+            ) throws IOException {
+                return new EarlyTerminatingCollectorManager<>(in, numHits, true);
+            }
         };
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/query/QueryCollectorManagerContext.java b/server/src/main/java/org/opensearch/search/query/QueryCollectorManagerContext.java
new file mode 100644
index 0000000000000..29e6244e05163
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/QueryCollectorManagerContext.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.MultiCollectorManager;
+import org.opensearch.search.profile.query.InternalProfileCollectorManager;
+import org.opensearch.search.profile.query.ProfileCollectorManager;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Context used for the query collector manager
+ *
+ * @opensearch.internal
+ */
+public abstract class QueryCollectorManagerContext {
+    private static class QueryCollectorManager implements CollectorManager<Collector, ReduceableSearchResult> {
+        private final MultiCollectorManager manager;
+
+        private QueryCollectorManager(Collection<CollectorManager<? extends Collector, ReduceableSearchResult>> managers) {
+            this.manager = new MultiCollectorManager(managers.toArray(new CollectorManager<?, ?>[0]));
+        }
+
+        @Override
+        public Collector newCollector() throws IOException {
+            return manager.newCollector();
+        }
+
+        @Override
+        public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+            final Object[] results = manager.reduce(collectors);
+
+            final ReduceableSearchResult[] transformed = new ReduceableSearchResult[results.length];
+            for (int i = 0; i < results.length; ++i) {
+                assert results[i] instanceof ReduceableSearchResult;
+                transformed[i] = (ReduceableSearchResult) results[i];
+            }
+
+            return reduceWith(transformed);
+        }
+
+        protected ReduceableSearchResult reduceWith(final ReduceableSearchResult[] results) {
+            return (QuerySearchResult result) -> {
+                for (final ReduceableSearchResult r : results) {
+                    r.reduce(result);
+                }
+            };
+        }
+    }
+
+    /**
+     * Create query {@link CollectorManager} tree using the provided query collector contexts
+     * @param collectorContexts list of {@link QueryCollectorContext}
+     * @return {@link CollectorManager} representing the manager tree for the query
+     */
+    public static CollectorManager<? extends Collector, ReduceableSearchResult> createQueryCollectorManager(
+        List<QueryCollectorContext> collectorContexts
+    ) throws IOException {
+        CollectorManager<?, ReduceableSearchResult> manager = null;
+        for (QueryCollectorContext ctx : collectorContexts) {
+            manager = ctx.createManager(manager);
+        }
+        return manager;
+    }
+
+    public static CollectorManager<? extends Collector, ReduceableSearchResult> createMultiCollectorManager(
+        List<CollectorManager<?, ReduceableSearchResult>> managers
+    ) {
+        return new QueryCollectorManager(managers);
+    }
+
+    public static ProfileCollectorManager<? extends Collector, ReduceableSearchResult> createQueryCollectorManagerWithProfiler(
+        List<QueryCollectorContext> collectors
+    ) throws IOException {
+        InternalProfileCollectorManager manager = null;
+
+        for (QueryCollectorContext ctx : collectors) {
+            manager = ctx.createWithProfiler(manager);
+        }
+
+        return manager;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/QueryPhase.java b/server/src/main/java/org/opensearch/search/query/QueryPhase.java
index 3edbc16cd613f..fa767f69d1ac6 100644
--- a/server/src/main/java/org/opensearch/search/query/QueryPhase.java
+++ b/server/src/main/java/org/opensearch/search/query/QueryPhase.java
@@ -36,14 +36,11 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.opensearch.lucene.queries.MinDocQuery;
-import org.opensearch.lucene.queries.SearchAfterSortedDocQuery;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Collector;
-import org.apache.lucene.search.ConstantScoreQuery;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.FieldDoc;
-import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.Sort;
@@ -54,26 +51,32 @@
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.concurrent.QueueResizingOpenSearchThreadPoolExecutor;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.lucene.queries.SearchAfterSortedDocQuery;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchContextSourcePrinter;
 import org.opensearch.search.SearchService;
-import org.opensearch.search.aggregations.AggregationPhase;
+import org.opensearch.search.aggregations.AggregationProcessor;
+import org.opensearch.search.aggregations.DefaultAggregationProcessor;
+import org.opensearch.search.aggregations.GlobalAggCollectorManager;
 import org.opensearch.search.internal.ContextIndexSearcher;
 import org.opensearch.search.internal.ScrollContext;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.profile.ProfileShardResult;
 import org.opensearch.search.profile.SearchProfileShardResults;
 import org.opensearch.search.profile.query.InternalProfileCollector;
-import org.opensearch.search.rescore.RescorePhase;
+import org.opensearch.search.rescore.RescoreProcessor;
 import org.opensearch.search.sort.SortAndFormats;
-import org.opensearch.search.suggest.SuggestPhase;
-import org.opensearch.tasks.TaskCancelledException;
+import org.opensearch.search.suggest.SuggestProcessor;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
 import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.ExecutorService;
+import java.util.stream.Collectors;
 
 import static org.opensearch.search.query.QueryCollectorContext.createEarlyTerminationCollectorContext;
 import static org.opensearch.search.query.QueryCollectorContext.createFilteredCollectorContext;
@@ -84,17 +87,17 @@
 /**
  * Query phase of a search request, used to run the query and get back from each shard information about the matching documents
  * (document ids and score or sort criteria) so that matches can be reduced on the coordinating node
+ *
+ * @opensearch.internal
  */
 public class QueryPhase {
     private static final Logger LOGGER = LogManager.getLogger(QueryPhase.class);
     // TODO: remove this property
     public static final boolean SYS_PROP_REWRITE_SORT = Booleans.parseBoolean(System.getProperty("opensearch.search.rewrite_sort", "true"));
     public static final QueryPhaseSearcher DEFAULT_QUERY_PHASE_SEARCHER = new DefaultQueryPhaseSearcher();
-
     private final QueryPhaseSearcher queryPhaseSearcher;
-    private final AggregationPhase aggregationPhase;
-    private final SuggestPhase suggestPhase;
-    private final RescorePhase rescorePhase;
+    private final SuggestProcessor suggestProcessor;
+    private final RescoreProcessor rescoreProcessor;
 
     public QueryPhase() {
         this(DEFAULT_QUERY_PHASE_SEARCHER);
@@ -102,9 +105,8 @@ public QueryPhase() {
 
     public QueryPhase(QueryPhaseSearcher queryPhaseSearcher) {
         this.queryPhaseSearcher = Objects.requireNonNull(queryPhaseSearcher, "QueryPhaseSearcher is required");
-        this.aggregationPhase = new AggregationPhase();
-        this.suggestPhase = new SuggestPhase();
-        this.rescorePhase = new RescorePhase();
+        this.suggestProcessor = new SuggestProcessor();
+        this.rescoreProcessor = new RescoreProcessor();
     }
 
     public void preProcess(SearchContext context) {
@@ -130,7 +132,7 @@ public void preProcess(SearchContext context) {
 
     public void execute(SearchContext searchContext) throws QueryPhaseExecutionException {
         if (searchContext.hasOnlySuggest()) {
-            suggestPhase.execute(searchContext);
+            suggestProcessor.process(searchContext);
             searchContext.queryResult()
                 .topDocs(
                     new TopDocsAndMaxScore(new TopDocs(new TotalHits(0, TotalHits.Relation.EQUAL_TO), Lucene.EMPTY_SCORE_DOCS), Float.NaN),
@@ -143,17 +145,18 @@ public void execute(SearchContext searchContext) throws QueryPhaseExecutionExcep
             LOGGER.trace("{}", new SearchContextSourcePrinter(searchContext));
         }
 
+        final AggregationProcessor aggregationProcessor = queryPhaseSearcher.aggregationProcessor(searchContext);
         // Pre-process aggregations as late as possible. In the case of a DFS_Q_T_F
         // request, preProcess is called on the DFS phase phase, this is why we pre-process them
         // here to make sure it happens during the QUERY phase
-        aggregationPhase.preProcess(searchContext);
+        aggregationProcessor.preProcess(searchContext);
         boolean rescore = executeInternal(searchContext, queryPhaseSearcher);
 
         if (rescore) { // only if we do a regular search
-            rescorePhase.execute(searchContext);
+            rescoreProcessor.process(searchContext);
         }
-        suggestPhase.execute(searchContext);
-        aggregationPhase.execute(searchContext);
+        suggestProcessor.process(searchContext);
+        aggregationProcessor.postProcess(searchContext);
 
         if (searchContext.getProfilers() != null) {
             ProfileShardResult shardResults = SearchProfileShardResults.buildShardResults(
@@ -164,6 +167,11 @@ public void execute(SearchContext searchContext) throws QueryPhaseExecutionExcep
         }
     }
 
+    // making public for testing
+    public QueryPhaseSearcher getQueryPhaseSearcher() {
+        return queryPhaseSearcher;
+    }
+
     /**
      * In a package-private method so that it can be tested without having to
      * wire everything (mapperService, etc.)
@@ -199,17 +207,7 @@ static boolean executeInternal(SearchContext searchContext, QueryPhaseSearcher q
 
                 } else {
                     final ScoreDoc after = scrollContext.lastEmittedDoc;
-                    if (returnsDocsInOrder(query, searchContext.sort())) {
-                        // now this gets interesting: since we sort in index-order, we can directly
-                        // skip to the desired doc
-                        if (after != null) {
-                            query = new BooleanQuery.Builder().add(query, BooleanClause.Occur.MUST)
-                                .add(new MinDocQuery(after.doc + 1), BooleanClause.Occur.FILTER)
-                                .build();
-                        }
-                        // ... and stop collecting after ${size} matches
-                        searchContext.terminateAfter(searchContext.size());
-                    } else if (canEarlyTerminate(reader, searchContext.sort())) {
+                    if (canEarlyTerminate(reader, searchContext.sort())) {
                         // now this gets interesting: since the search sort is a prefix of the index sort, we can directly
                         // skip to the desired doc
                         if (after != null) {
@@ -238,10 +236,19 @@ static boolean executeInternal(SearchContext searchContext, QueryPhaseSearcher q
                 // this collector can filter documents during the collection
                 hasFilterCollector = true;
             }
-            if (searchContext.queryCollectors().isEmpty() == false) {
-                // plug in additional collectors, like aggregations
-                collectors.add(createMultiCollectorContext(searchContext.queryCollectors().values()));
+
+            // plug in additional collectors, like aggregations except global aggregations
+            final List<CollectorManager<? extends Collector, ReduceableSearchResult>> managersExceptGlobalAgg = searchContext
+                .queryCollectorManagers()
+                .entrySet()
+                .stream()
+                .filter(entry -> !(entry.getKey().equals(GlobalAggCollectorManager.class)))
+                .map(Map.Entry::getValue)
+                .collect(Collectors.toList());
+            if (managersExceptGlobalAgg.isEmpty() == false) {
+                collectors.add(createMultiCollectorContext(managersExceptGlobalAgg));
             }
+
             if (searchContext.minimumScore() != null) {
                 // apply the minimum score after multi collector so we filter aggs as well
                 collectors.add(createMinScoreCollectorContext(searchContext.minimumScore()));
@@ -255,15 +262,7 @@ static boolean executeInternal(SearchContext searchContext, QueryPhaseSearcher q
 
             final Runnable timeoutRunnable;
             if (timeoutSet) {
-                final long startTime = searchContext.getRelativeTimeInMillis();
-                final long timeout = searchContext.timeout().millis();
-                final long maxTime = startTime + timeout;
-                timeoutRunnable = searcher.addQueryCancellation(() -> {
-                    final long time = searchContext.getRelativeTimeInMillis();
-                    if (time > maxTime) {
-                        throw new TimeExceededException();
-                    }
-                });
+                timeoutRunnable = searcher.addQueryCancellation(createQueryTimeoutChecker(searchContext));
             } else {
                 timeoutRunnable = null;
             }
@@ -307,6 +306,28 @@ static boolean executeInternal(SearchContext searchContext, QueryPhaseSearcher q
         }
     }
 
+    /**
+     * Create runnable which throws {@link TimeExceededException} when the runnable is called after timeout + runnable creation time
+     * exceeds currentTime
+     * @param searchContext to extract timeout from and to get relative time from
+     * @return the created runnable
+     */
+    static Runnable createQueryTimeoutChecker(final SearchContext searchContext) {
+        /* for startTime, relative non-cached precise time must be used to prevent false positive timeouts.
+        * Using cached time for startTime will fail and produce false positive timeouts when maxTime = (startTime + timeout) falls in
+        * next time cache slot(s) AND time caching lifespan > passed timeout */
+        final long startTime = searchContext.getRelativeTimeInMillis(false);
+        final long maxTime = startTime + searchContext.timeout().millis();
+        return () -> {
+            /* As long as startTime is non cached time, using cached time here might only produce false negative timeouts within the time
+            * cache life span which is acceptable */
+            final long time = searchContext.getRelativeTimeInMillis();
+            if (time > maxTime) {
+                throw new TimeExceededException();
+            }
+        };
+    }
+
     private static boolean searchWithCollector(
         SearchContext searchContext,
         ContextIndexSearcher searcher,
@@ -333,10 +354,10 @@ private static boolean searchWithCollector(
             searcher.search(query, queryCollector);
         } catch (EarlyTerminatingCollector.EarlyTerminationException e) {
             queryResult.terminatedEarly(true);
-        } catch (TimeExceededException e) {
+        }
+        if (searchContext.isSearchTimedOut()) {
             assert timeoutSet : "TimeExceededException thrown even though timeout wasn't set";
             if (searchContext.request().allowPartialSearchResults() == false) {
-                // Can't rethrow TimeExceededException because not serializable
                 throw new QueryPhaseExecutionException(searchContext.shardTarget(), "Time exceeded");
             }
             queryResult.searchTimedOut(true);
@@ -350,22 +371,6 @@ private static boolean searchWithCollector(
         return topDocsFactory.shouldRescore();
     }
 
-    /**
-     * Returns true if the provided <code>query</code> returns docs in index order (internal doc ids).
-     * @param query The query to execute
-     * @param sf The query sort
-     */
-    private static boolean returnsDocsInOrder(Query query, SortAndFormats sf) {
-        if (sf == null || Sort.RELEVANCE.equals(sf.sort)) {
-            // sort by score
-            // queries that return constant scores will return docs in index
-            // order since Lucene tie-breaks on the doc id
-            return query.getClass() == ConstantScoreQuery.class || query.getClass() == MatchAllDocsQuery.class;
-        } else {
-            return Sort.INDEXORDER.equals(sf.sort);
-        }
-    }
-
     /**
      * Returns whether collection within the provided <code>reader</code> can be early-terminated if it sorts
      * with <code>sortAndFormats</code>.
@@ -386,6 +391,8 @@ private static boolean canEarlyTerminate(IndexReader reader, SortAndFormats sort
 
     /**
      * The exception being raised when search timeout is reached.
+     *
+     * @opensearch.internal
      */
     public static class TimeExceededException extends RuntimeException {
         private static final long serialVersionUID = 1L;
@@ -393,12 +400,18 @@ public static class TimeExceededException extends RuntimeException {
 
     /**
      * Default {@link QueryPhaseSearcher} implementation which delegates to the {@link QueryPhase}.
+     *
+     * @opensearch.internal
      */
     public static class DefaultQueryPhaseSearcher implements QueryPhaseSearcher {
+        private final AggregationProcessor aggregationProcessor;
+
         /**
          * Please use {@link QueryPhase#DEFAULT_QUERY_PHASE_SEARCHER}
          */
-        protected DefaultQueryPhaseSearcher() {}
+        protected DefaultQueryPhaseSearcher() {
+            aggregationProcessor = new DefaultAggregationProcessor();
+        }
 
         @Override
         public boolean searchWith(
@@ -412,6 +425,11 @@ public boolean searchWith(
             return searchWithCollector(searchContext, searcher, query, collectors, hasFilterCollector, hasTimeout);
         }
 
+        @Override
+        public AggregationProcessor aggregationProcessor(SearchContext searchContext) {
+            return aggregationProcessor;
+        }
+
         protected boolean searchWithCollector(
             SearchContext searchContext,
             ContextIndexSearcher searcher,
diff --git a/server/src/main/java/org/opensearch/search/query/QueryPhaseExecutionException.java b/server/src/main/java/org/opensearch/search/query/QueryPhaseExecutionException.java
index 45d038393637a..43bd87183d0be 100644
--- a/server/src/main/java/org/opensearch/search/query/QueryPhaseExecutionException.java
+++ b/server/src/main/java/org/opensearch/search/query/QueryPhaseExecutionException.java
@@ -32,12 +32,17 @@
 
 package org.opensearch.search.query;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.SearchException;
 import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Thrown if there are any errors in the query phase
+ *
+ * @opensearch.internal
+ */
 public class QueryPhaseExecutionException extends SearchException {
 
     public QueryPhaseExecutionException(SearchShardTarget shardTarget, String msg, Throwable cause) {
diff --git a/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcher.java b/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcher.java
index 9a48f030fe147..4518b5e71bdf3 100644
--- a/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcher.java
+++ b/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcher.java
@@ -10,6 +10,8 @@
 
 import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.Query;
+import org.opensearch.search.aggregations.AggregationProcessor;
+import org.opensearch.search.aggregations.DefaultAggregationProcessor;
 import org.opensearch.search.internal.ContextIndexSearcher;
 import org.opensearch.search.internal.SearchContext;
 
@@ -19,6 +21,8 @@
 /**
  * The extension point which allows to plug in custom search implementation to be
  * used at {@link QueryPhase}.
+ *
+ * @opensearch.internal
  */
 public interface QueryPhaseSearcher {
     /**
@@ -38,4 +42,13 @@ boolean searchWith(
         boolean hasFilterCollector,
         boolean hasTimeout
     ) throws IOException;
+
+    /**
+     * {@link AggregationProcessor} to use to setup and post process aggregation related collectors during search request
+     * @param searchContext search context
+     * @return {@link AggregationProcessor} to use
+     */
+    default AggregationProcessor aggregationProcessor(SearchContext searchContext) {
+        return new DefaultAggregationProcessor();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcherWrapper.java b/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcherWrapper.java
new file mode 100644
index 0000000000000..631ace41090d7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/QueryPhaseSearcherWrapper.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.Query;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.search.aggregations.AggregationProcessor;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.LinkedList;
+
+/**
+ * Wrapper class for QueryPhaseSearcher that handles path selection for concurrent vs
+ * non-concurrent search query phase and aggregation processor.
+ *
+ * @opensearch.internal
+ */
+public class QueryPhaseSearcherWrapper implements QueryPhaseSearcher {
+    private static final Logger LOGGER = LogManager.getLogger(QueryPhaseSearcherWrapper.class);
+    private final QueryPhaseSearcher defaultQueryPhaseSearcher;
+    private final QueryPhaseSearcher concurrentQueryPhaseSearcher;
+
+    public QueryPhaseSearcherWrapper() {
+        this.defaultQueryPhaseSearcher = new QueryPhase.DefaultQueryPhaseSearcher();
+        this.concurrentQueryPhaseSearcher = FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)
+            ? new ConcurrentQueryPhaseSearcher()
+            : null;
+    }
+
+    /**
+     * Perform search using {@link CollectorManager}
+     *
+     * @param searchContext      search context
+     * @param searcher           context index searcher
+     * @param query              query
+     * @param hasTimeout         "true" if timeout was set, "false" otherwise
+     * @return is rescoring required or not
+     * @throws java.io.IOException IOException
+     */
+    @Override
+    public boolean searchWith(
+        SearchContext searchContext,
+        ContextIndexSearcher searcher,
+        Query query,
+        LinkedList<QueryCollectorContext> collectors,
+        boolean hasFilterCollector,
+        boolean hasTimeout
+    ) throws IOException {
+        if (searchContext.shouldUseConcurrentSearch()) {
+            LOGGER.debug("Using concurrent search over segments (experimental) for request with context id {}", searchContext.id());
+            return concurrentQueryPhaseSearcher.searchWith(searchContext, searcher, query, collectors, hasFilterCollector, hasTimeout);
+        } else {
+            LOGGER.debug("Using non-concurrent search over segments for request with context id {}", searchContext.id());
+            return defaultQueryPhaseSearcher.searchWith(searchContext, searcher, query, collectors, hasFilterCollector, hasTimeout);
+        }
+    }
+
+    /**
+     * {@link AggregationProcessor} to use to setup and post process aggregation related collectors during search request
+     * @param searchContext search context
+     * @return {@link AggregationProcessor} to use
+     */
+    @Override
+    public AggregationProcessor aggregationProcessor(SearchContext searchContext) {
+        if (searchContext.shouldUseConcurrentSearch()) {
+            LOGGER.debug(
+                "Using concurrent aggregation processor over segments (experimental) for request with context id {}",
+                searchContext.id()
+            );
+            return concurrentQueryPhaseSearcher.aggregationProcessor(searchContext);
+        } else {
+            LOGGER.debug("Using non-concurrent aggregation processor over segments for request with context id {}", searchContext.id());
+            return defaultQueryPhaseSearcher.aggregationProcessor(searchContext);
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/QuerySearchRequest.java b/server/src/main/java/org/opensearch/search/query/QuerySearchRequest.java
index 0e7cacf013993..b7cf1c4dd4e32 100644
--- a/server/src/main/java/org/opensearch/search/query/QuerySearchRequest.java
+++ b/server/src/main/java/org/opensearch/search/query/QuerySearchRequest.java
@@ -38,19 +38,24 @@
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.search.dfs.AggregatedDfs;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 import java.util.Map;
 
+/**
+ * Transport request for query search
+ *
+ * @opensearch.internal
+ */
 public class QuerySearchRequest extends TransportRequest implements IndicesRequest {
 
     private final ShardSearchContextId contextId;
@@ -118,7 +123,7 @@ public IndicesOptions indicesOptions() {
 
     @Override
     public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
-        return new SearchShardTask(id, type, action, getDescription(), parentTaskId, headers);
+        return new SearchShardTask(id, type, action, getDescription(), parentTaskId, headers, this::getMetadataSupplier);
     }
 
     public String getDescription() {
@@ -132,4 +137,7 @@ public String getDescription() {
         return sb.toString();
     }
 
+    public String getMetadataSupplier() {
+        return shardSearchRequest().getMetadataSupplier();
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/query/QuerySearchResult.java b/server/src/main/java/org/opensearch/search/query/QuerySearchResult.java
index ee506bbc6ed67..1b113e4ba7551 100644
--- a/server/src/main/java/org/opensearch/search/query/QuerySearchResult.java
+++ b/server/src/main/java/org/opensearch/search/query/QuerySearchResult.java
@@ -36,9 +36,9 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.io.stream.DelayableWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.RescoreDocIds;
 import org.opensearch.search.SearchPhaseResult;
@@ -58,6 +58,11 @@
 import static org.opensearch.common.lucene.Lucene.readTopDocs;
 import static org.opensearch.common.lucene.Lucene.writeTopDocs;
 
+/**
+ * The result of the query search
+ *
+ * @opensearch.internal
+ */
 public final class QuerySearchResult extends SearchPhaseResult {
 
     private int from;
diff --git a/server/src/main/java/org/opensearch/search/query/ReduceableSearchResult.java b/server/src/main/java/org/opensearch/search/query/ReduceableSearchResult.java
new file mode 100644
index 0000000000000..dbfaa70e1968f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/ReduceableSearchResult.java
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import java.io.IOException;
+
+/**
+ * The search result callback returned by reduce phase of the collector manager.
+ *
+ * @opensearch.internal
+ */
+public interface ReduceableSearchResult {
+    /**
+     * Apply the reduce operation to the query search results
+     * @param result query search results
+     * @throws IOException exception if reduce operation failed
+     */
+    void reduce(QuerySearchResult result) throws IOException;
+}
diff --git a/server/src/main/java/org/opensearch/search/query/ScrollQuerySearchResult.java b/server/src/main/java/org/opensearch/search/query/ScrollQuerySearchResult.java
index 278a1ee2b09d0..0cdc8749253f0 100644
--- a/server/src/main/java/org/opensearch/search/query/ScrollQuerySearchResult.java
+++ b/server/src/main/java/org/opensearch/search/query/ScrollQuerySearchResult.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.query;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 
 import java.io.IOException;
 
+/**
+ * Scrolled results from a query search request
+ *
+ * @opensearch.internal
+ */
 public final class ScrollQuerySearchResult extends SearchPhaseResult {
 
     private final QuerySearchResult result;
diff --git a/server/src/main/java/org/opensearch/search/query/TopDocsCollectorContext.java b/server/src/main/java/org/opensearch/search/query/TopDocsCollectorContext.java
index 9cf7dca3c4caf..86f6e542f97d1 100644
--- a/server/src/main/java/org/opensearch/search/query/TopDocsCollectorContext.java
+++ b/server/src/main/java/org/opensearch/search/query/TopDocsCollectorContext.java
@@ -44,6 +44,7 @@
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.FieldDoc;
@@ -80,6 +81,9 @@
 import org.opensearch.search.sort.SortAndFormats;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Objects;
 import java.util.function.Supplier;
 
@@ -88,8 +92,10 @@
 
 /**
  * A {@link QueryCollectorContext} that creates top docs collector
+ *
+ * @opensearch.internal
  */
-abstract class TopDocsCollectorContext extends QueryCollectorContext {
+public abstract class TopDocsCollectorContext extends QueryCollectorContext {
     protected final int numHits;
 
     TopDocsCollectorContext(String profilerName, int numHits) {
@@ -107,7 +113,7 @@ final int numHits() {
     /**
      * Returns true if the top docs should be re-scored after initial search
      */
-    boolean shouldRescore() {
+    public boolean shouldRescore() {
         return false;
     }
 
@@ -115,6 +121,8 @@ static class EmptyTopDocsCollectorContext extends TopDocsCollectorContext {
         private final Sort sort;
         private final Collector collector;
         private final Supplier<TotalHits> hitCountSupplier;
+        private final int trackTotalHitsUpTo;
+        private final int hitCount;
 
         /**
          * Ctr
@@ -132,16 +140,18 @@ private EmptyTopDocsCollectorContext(
         ) throws IOException {
             super(REASON_SEARCH_COUNT, 0);
             this.sort = sortAndFormats == null ? null : sortAndFormats.sort;
-            if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
+            this.trackTotalHitsUpTo = trackTotalHitsUpTo;
+            if (this.trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
                 this.collector = new EarlyTerminatingCollector(new TotalHitCountCollector(), 0, false);
                 // for bwc hit count is set to 0, it will be converted to -1 by the coordinating node
                 this.hitCountSupplier = () -> new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+                this.hitCount = Integer.MIN_VALUE;
             } else {
                 TotalHitCountCollector hitCountCollector = new TotalHitCountCollector();
                 // implicit total hit counts are valid only when there is no filter collector in the chain
-                int hitCount = hasFilterCollector ? -1 : shortcutTotalHitCount(reader, query);
-                if (hitCount == -1) {
-                    if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_ACCURATE) {
+                this.hitCount = hasFilterCollector ? -1 : shortcutTotalHitCount(reader, query);
+                if (this.hitCount == -1) {
+                    if (this.trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_ACCURATE) {
                         this.collector = hitCountCollector;
                         this.hitCountSupplier = () -> new TotalHits(hitCountCollector.getTotalHits(), TotalHits.Relation.EQUAL_TO);
                     } else {
@@ -159,6 +169,41 @@ private EmptyTopDocsCollectorContext(
             }
         }
 
+        @Override
+        CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException {
+            assert in == null;
+
+            CollectorManager<?, ReduceableSearchResult> manager = null;
+
+            if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
+                manager = new EarlyTerminatingCollectorManager<>(
+                    new TotalHitCountCollectorManager.Empty(new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO), sort),
+                    0,
+                    false
+                );
+            } else {
+                if (hitCount == -1) {
+                    if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_ACCURATE) {
+                        manager = new TotalHitCountCollectorManager(sort);
+                    } else {
+                        manager = new EarlyTerminatingCollectorManager<>(
+                            new TotalHitCountCollectorManager(sort),
+                            trackTotalHitsUpTo,
+                            false
+                        );
+                    }
+                } else {
+                    manager = new EarlyTerminatingCollectorManager<>(
+                        new TotalHitCountCollectorManager.Empty(new TotalHits(hitCount, TotalHits.Relation.EQUAL_TO), sort),
+                        0,
+                        false
+                    );
+                }
+            }
+
+            return manager;
+        }
+
         @Override
         Collector create(Collector in) {
             assert in == null;
@@ -181,7 +226,11 @@ void postProcess(QuerySearchResult result) {
     static class CollapsingTopDocsCollectorContext extends TopDocsCollectorContext {
         private final DocValueFormat[] sortFmt;
         private final CollapsingTopDocsCollector<?> topDocsCollector;
+        private final Collector collector;
         private final Supplier<Float> maxScoreSupplier;
+        private final CollapseContext collapseContext;
+        private final boolean trackMaxScore;
+        private final Sort sort;
 
         /**
          * Ctr
@@ -199,30 +248,94 @@ private CollapsingTopDocsCollectorContext(
             super(REASON_SEARCH_TOP_HITS, numHits);
             assert numHits > 0;
             assert collapseContext != null;
-            Sort sort = sortAndFormats == null ? Sort.RELEVANCE : sortAndFormats.sort;
+            this.sort = sortAndFormats == null ? Sort.RELEVANCE : sortAndFormats.sort;
             this.sortFmt = sortAndFormats == null ? new DocValueFormat[] { DocValueFormat.RAW } : sortAndFormats.formats;
+            this.collapseContext = collapseContext;
             this.topDocsCollector = collapseContext.createTopDocs(sort, numHits);
+            this.trackMaxScore = trackMaxScore;
 
-            MaxScoreCollector maxScoreCollector;
+            MaxScoreCollector maxScoreCollector = null;
             if (trackMaxScore) {
                 maxScoreCollector = new MaxScoreCollector();
                 maxScoreSupplier = maxScoreCollector::getMaxScore;
             } else {
+                maxScoreCollector = null;
                 maxScoreSupplier = () -> Float.NaN;
             }
+
+            this.collector = MultiCollector.wrap(topDocsCollector, maxScoreCollector);
         }
 
         @Override
         Collector create(Collector in) throws IOException {
             assert in == null;
-            return topDocsCollector;
+            return collector;
         }
 
         @Override
         void postProcess(QuerySearchResult result) throws IOException {
-            CollapseTopFieldDocs topDocs = topDocsCollector.getTopDocs();
+            final CollapseTopFieldDocs topDocs = topDocsCollector.getTopDocs();
             result.topDocs(new TopDocsAndMaxScore(topDocs, maxScoreSupplier.get()), sortFmt);
         }
+
+        @Override
+        CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException {
+            return new CollectorManager<Collector, ReduceableSearchResult>() {
+                @Override
+                public Collector newCollector() throws IOException {
+                    MaxScoreCollector maxScoreCollector = null;
+
+                    if (trackMaxScore) {
+                        maxScoreCollector = new MaxScoreCollector();
+                    }
+
+                    return MultiCollectorWrapper.wrap(collapseContext.createTopDocs(sort, numHits), maxScoreCollector);
+                }
+
+                @Override
+                public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+                    final Collection<Collector> subs = new ArrayList<>();
+                    for (final Collector collector : collectors) {
+                        if (collector instanceof MultiCollectorWrapper) {
+                            subs.addAll(((MultiCollectorWrapper) collector).getCollectors());
+                        } else {
+                            subs.add(collector);
+                        }
+                    }
+
+                    final Collection<CollapseTopFieldDocs> topFieldDocs = new ArrayList<CollapseTopFieldDocs>();
+                    float maxScore = Float.NaN;
+
+                    for (final Collector collector : subs) {
+                        if (collector instanceof CollapsingTopDocsCollector<?>) {
+                            topFieldDocs.add(((CollapsingTopDocsCollector<?>) collector).getTopDocs());
+                        } else if (collector instanceof MaxScoreCollector) {
+                            float score = ((MaxScoreCollector) collector).getMaxScore();
+                            if (Float.isNaN(maxScore)) {
+                                maxScore = score;
+                            } else {
+                                maxScore = Math.max(maxScore, score);
+                            }
+                        }
+                    }
+
+                    return reduceWith(topFieldDocs, maxScore);
+                }
+            };
+        }
+
+        protected ReduceableSearchResult reduceWith(final Collection<CollapseTopFieldDocs> topFieldDocs, float maxScore) {
+            return (QuerySearchResult result) -> {
+                final CollapseTopFieldDocs topDocs = CollapseTopFieldDocs.merge(
+                    sort,
+                    0,
+                    numHits,
+                    topFieldDocs.toArray(new CollapseTopFieldDocs[0]),
+                    true
+                );
+                result.topDocs(new TopDocsAndMaxScore(topDocs, maxScore), sortFmt);
+            };
+        }
     }
 
     abstract static class SimpleTopDocsCollectorContext extends TopDocsCollectorContext {
@@ -240,11 +353,38 @@ private static TopDocsCollector<?> createCollector(
             }
         }
 
+        private static CollectorManager<? extends TopDocsCollector<?>, ? extends TopDocs> createCollectorManager(
+            @Nullable SortAndFormats sortAndFormats,
+            int numHits,
+            @Nullable ScoreDoc searchAfter,
+            int hitCountThreshold
+        ) {
+            if (sortAndFormats == null) {
+                // See please https://github.com/apache/lucene/pull/450, should be fixed in 9.x
+                if (searchAfter != null) {
+                    return TopScoreDocCollector.createSharedManager(
+                        numHits,
+                        new FieldDoc(searchAfter.doc, searchAfter.score),
+                        hitCountThreshold
+                    );
+                } else {
+                    return TopScoreDocCollector.createSharedManager(numHits, null, hitCountThreshold);
+                }
+            } else {
+                return TopFieldCollector.createSharedManager(sortAndFormats.sort, numHits, (FieldDoc) searchAfter, hitCountThreshold);
+            }
+        }
+
         protected final @Nullable SortAndFormats sortAndFormats;
         private final Collector collector;
         private final Supplier<TotalHits> totalHitsSupplier;
         private final Supplier<TopDocs> topDocsSupplier;
         private final Supplier<Float> maxScoreSupplier;
+        private final ScoreDoc searchAfter;
+        private final int trackTotalHitsUpTo;
+        private final boolean trackMaxScore;
+        private final boolean hasInfMaxScore;
+        private final int hitCount;
 
         /**
          * Ctr
@@ -269,24 +409,30 @@ private SimpleTopDocsCollectorContext(
         ) throws IOException {
             super(REASON_SEARCH_TOP_HITS, numHits);
             this.sortAndFormats = sortAndFormats;
+            this.searchAfter = searchAfter;
+            this.trackTotalHitsUpTo = trackTotalHitsUpTo;
+            this.trackMaxScore = trackMaxScore;
+            this.hasInfMaxScore = hasInfMaxScore(query);
 
             final TopDocsCollector<?> topDocsCollector;
 
-            if ((sortAndFormats == null || SortField.FIELD_SCORE.equals(sortAndFormats.sort.getSort()[0])) && hasInfMaxScore(query)) {
+            if ((sortAndFormats == null || SortField.FIELD_SCORE.equals(sortAndFormats.sort.getSort()[0])) && hasInfMaxScore) {
                 // disable max score optimization since we have a mandatory clause
                 // that doesn't track the maximum score
                 topDocsCollector = createCollector(sortAndFormats, numHits, searchAfter, Integer.MAX_VALUE);
                 topDocsSupplier = new CachedSupplier<>(topDocsCollector::topDocs);
                 totalHitsSupplier = () -> topDocsSupplier.get().totalHits;
+                hitCount = Integer.MIN_VALUE;
             } else if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
                 // don't compute hit counts via the collector
                 topDocsCollector = createCollector(sortAndFormats, numHits, searchAfter, 1);
                 topDocsSupplier = new CachedSupplier<>(topDocsCollector::topDocs);
                 totalHitsSupplier = () -> new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+                hitCount = -1;
             } else {
                 // implicit total hit counts are valid only when there is no filter collector in the chain
-                final int hitCount = hasFilterCollector ? -1 : shortcutTotalHitCount(reader, query);
-                if (hitCount == -1) {
+                this.hitCount = hasFilterCollector ? -1 : shortcutTotalHitCount(reader, query);
+                if (this.hitCount == -1) {
                     topDocsCollector = createCollector(sortAndFormats, numHits, searchAfter, trackTotalHitsUpTo);
                     topDocsSupplier = new CachedSupplier<>(topDocsCollector::topDocs);
                     totalHitsSupplier = () -> topDocsSupplier.get().totalHits;
@@ -294,7 +440,7 @@ private SimpleTopDocsCollectorContext(
                     // don't compute hit counts via the collector
                     topDocsCollector = createCollector(sortAndFormats, numHits, searchAfter, 1);
                     topDocsSupplier = new CachedSupplier<>(topDocsCollector::topDocs);
-                    totalHitsSupplier = () -> new TotalHits(hitCount, TotalHits.Relation.EQUAL_TO);
+                    totalHitsSupplier = () -> new TotalHits(this.hitCount, TotalHits.Relation.EQUAL_TO);
                 }
             }
             MaxScoreCollector maxScoreCollector = null;
@@ -315,7 +461,98 @@ private SimpleTopDocsCollectorContext(
             }
 
             this.collector = MultiCollector.wrap(topDocsCollector, maxScoreCollector);
+        }
 
+        private class SimpleTopDocsCollectorManager
+            implements
+                CollectorManager<Collector, ReduceableSearchResult>,
+                EarlyTerminatingListener {
+            private Integer terminatedAfter;
+            private final CollectorManager<? extends TopDocsCollector<?>, ? extends TopDocs> manager;
+
+            private SimpleTopDocsCollectorManager() {
+                if ((sortAndFormats == null || SortField.FIELD_SCORE.equals(sortAndFormats.sort.getSort()[0])) && hasInfMaxScore) {
+                    // disable max score optimization since we have a mandatory clause
+                    // that doesn't track the maximum score
+                    manager = createCollectorManager(sortAndFormats, numHits, searchAfter, Integer.MAX_VALUE);
+                } else if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
+                    // don't compute hit counts via the collector
+                    manager = createCollectorManager(sortAndFormats, numHits, searchAfter, 1);
+                } else {
+                    // implicit total hit counts are valid only when there is no filter collector in the chain
+                    if (hitCount == -1) {
+                        manager = createCollectorManager(sortAndFormats, numHits, searchAfter, trackTotalHitsUpTo);
+                    } else {
+                        // don't compute hit counts via the collector
+                        manager = createCollectorManager(sortAndFormats, numHits, searchAfter, 1);
+                    }
+                }
+            }
+
+            @Override
+            public void onEarlyTermination(int maxCountHits, boolean forcedTermination) {
+                terminatedAfter = maxCountHits;
+            }
+
+            @Override
+            public Collector newCollector() throws IOException {
+                MaxScoreCollector maxScoreCollector = null;
+
+                if (sortAndFormats != null && trackMaxScore) {
+                    maxScoreCollector = new MaxScoreCollector();
+                }
+
+                return MultiCollectorWrapper.wrap(manager.newCollector(), maxScoreCollector);
+            }
+
+            @SuppressWarnings("unchecked")
+            @Override
+            public ReduceableSearchResult reduce(Collection<Collector> collectors) throws IOException {
+                final Collection<TopDocsCollector<?>> topDocsCollectors = new ArrayList<>();
+                final Collection<MaxScoreCollector> maxScoreCollectors = new ArrayList<>();
+
+                for (final Collector collector : collectors) {
+                    if (collector instanceof MultiCollectorWrapper) {
+                        for (final Collector sub : (((MultiCollectorWrapper) collector).getCollectors())) {
+                            if (sub instanceof TopDocsCollector<?>) {
+                                topDocsCollectors.add((TopDocsCollector<?>) sub);
+                            } else if (sub instanceof MaxScoreCollector) {
+                                maxScoreCollectors.add((MaxScoreCollector) sub);
+                            }
+                        }
+                    } else if (collector instanceof TopDocsCollector<?>) {
+                        topDocsCollectors.add((TopDocsCollector<?>) collector);
+                    } else if (collector instanceof MaxScoreCollector) {
+                        maxScoreCollectors.add((MaxScoreCollector) collector);
+                    }
+                }
+
+                float maxScore = Float.NaN;
+                for (final MaxScoreCollector collector : maxScoreCollectors) {
+                    float score = collector.getMaxScore();
+                    if (Float.isNaN(maxScore)) {
+                        maxScore = score;
+                    } else {
+                        maxScore = Math.max(maxScore, score);
+                    }
+                }
+
+                final TopDocs topDocs = ((CollectorManager<TopDocsCollector<?>, ? extends TopDocs>) manager).reduce(topDocsCollectors);
+                return reduceWith(topDocs, maxScore, terminatedAfter);
+            }
+        }
+
+        @Override
+        CollectorManager<?, ReduceableSearchResult> createManager(CollectorManager<?, ReduceableSearchResult> in) throws IOException {
+            assert in == null;
+            return new SimpleTopDocsCollectorManager();
+        }
+
+        protected ReduceableSearchResult reduceWith(final TopDocs topDocs, final float maxScore, final Integer terminatedAfter) {
+            return (QuerySearchResult result) -> {
+                final TopDocsAndMaxScore topDocsAndMaxScore = newTopDocs(topDocs, maxScore, terminatedAfter);
+                result.topDocs(topDocsAndMaxScore, sortAndFormats == null ? null : sortAndFormats.formats);
+            };
         }
 
         @Override
@@ -324,6 +561,50 @@ Collector create(Collector in) {
             return collector;
         }
 
+        TopDocsAndMaxScore newTopDocs(final TopDocs topDocs, final float maxScore, final Integer terminatedAfter) {
+            TotalHits totalHits = null;
+
+            if ((sortAndFormats == null || SortField.FIELD_SCORE.equals(sortAndFormats.sort.getSort()[0])) && hasInfMaxScore) {
+                totalHits = topDocs.totalHits;
+            } else if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
+                // don't compute hit counts via the collector
+                totalHits = new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+            } else {
+                if (hitCount == -1) {
+                    totalHits = topDocs.totalHits;
+                } else {
+                    totalHits = new TotalHits(hitCount, TotalHits.Relation.EQUAL_TO);
+                }
+            }
+
+            // Since we cannot support early forced termination, we have to simulate it by
+            // artificially reducing the number of total hits and doc scores.
+            ScoreDoc[] scoreDocs = topDocs.scoreDocs;
+            if (terminatedAfter != null) {
+                if (totalHits.value > terminatedAfter) {
+                    totalHits = new TotalHits(terminatedAfter, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+                }
+
+                if (scoreDocs != null && scoreDocs.length > terminatedAfter) {
+                    scoreDocs = Arrays.copyOf(scoreDocs, terminatedAfter);
+                }
+            }
+
+            final TopDocs newTopDocs;
+            if (topDocs instanceof TopFieldDocs) {
+                TopFieldDocs fieldDocs = (TopFieldDocs) topDocs;
+                newTopDocs = new TopFieldDocs(totalHits, scoreDocs, fieldDocs.fields);
+            } else {
+                newTopDocs = new TopDocs(totalHits, scoreDocs);
+            }
+
+            if (Float.isNaN(maxScore) && newTopDocs.scoreDocs.length > 0 && sortAndFormats == null) {
+                return new TopDocsAndMaxScore(newTopDocs, newTopDocs.scoreDocs[0].score);
+            } else {
+                return new TopDocsAndMaxScore(newTopDocs, maxScore);
+            }
+        }
+
         TopDocsAndMaxScore newTopDocs() {
             TopDocs in = topDocsSupplier.get();
             float maxScore = maxScoreSupplier.get();
@@ -373,6 +654,35 @@ private ScrollingTopDocsCollectorContext(
             this.numberOfShards = numberOfShards;
         }
 
+        @Override
+        protected ReduceableSearchResult reduceWith(final TopDocs topDocs, final float maxScore, final Integer terminatedAfter) {
+            return (QuerySearchResult result) -> {
+                final TopDocsAndMaxScore topDocsAndMaxScore = newTopDocs(topDocs, maxScore, terminatedAfter);
+
+                if (scrollContext.totalHits == null) {
+                    // first round
+                    scrollContext.totalHits = topDocsAndMaxScore.topDocs.totalHits;
+                    scrollContext.maxScore = topDocsAndMaxScore.maxScore;
+                } else {
+                    // subsequent round: the total number of hits and
+                    // the maximum score were computed on the first round
+                    topDocsAndMaxScore.topDocs.totalHits = scrollContext.totalHits;
+                    topDocsAndMaxScore.maxScore = scrollContext.maxScore;
+                }
+
+                if (numberOfShards == 1) {
+                    // if we fetch the document in the same roundtrip, we already know the last emitted doc
+                    if (topDocsAndMaxScore.topDocs.scoreDocs.length > 0) {
+                        // set the last emitted doc
+                        scrollContext.lastEmittedDoc = topDocsAndMaxScore.topDocs.scoreDocs[topDocsAndMaxScore.topDocs.scoreDocs.length
+                            - 1];
+                    }
+                }
+
+                result.topDocs(topDocsAndMaxScore, sortAndFormats == null ? null : sortAndFormats.formats);
+            };
+        }
+
         @Override
         void postProcess(QuerySearchResult result) throws IOException {
             final TopDocsAndMaxScore topDocs = newTopDocs();
@@ -457,7 +767,7 @@ static int shortcutTotalHitCount(IndexReader reader, Query query) throws IOExcep
      * Creates a {@link TopDocsCollectorContext} from the provided <code>searchContext</code>.
      * @param hasFilterCollector True if the collector chain contains at least one collector that can filters document.
      */
-    static TopDocsCollectorContext createTopDocsCollectorContext(SearchContext searchContext, boolean hasFilterCollector)
+    public static TopDocsCollectorContext createTopDocsCollectorContext(SearchContext searchContext, boolean hasFilterCollector)
         throws IOException {
         final IndexReader reader = searchContext.searcher().getIndexReader();
         final Query query = searchContext.query();
@@ -515,7 +825,7 @@ static TopDocsCollectorContext createTopDocsCollectorContext(SearchContext searc
                 hasFilterCollector
             ) {
                 @Override
-                boolean shouldRescore() {
+                public boolean shouldRescore() {
                     return rescore;
                 }
             };
diff --git a/server/src/main/java/org/opensearch/search/query/TotalHitCountCollectorManager.java b/server/src/main/java/org/opensearch/search/query/TotalHitCountCollectorManager.java
new file mode 100644
index 0000000000000..e89a4ba3bae59
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/TotalHitCountCollectorManager.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.LeafCollector;
+import org.apache.lucene.search.Scorable;
+import org.apache.lucene.search.ScoreMode;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TopFieldDocs;
+import org.apache.lucene.search.TotalHitCountCollector;
+import org.apache.lucene.search.TotalHits;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+
+import java.io.IOException;
+import java.util.Collection;
+
+/**
+ * CollectorManager for the TotalHitCountCollector
+ *
+ * @opensearch.internal
+ */
+public class TotalHitCountCollectorManager
+    implements
+        CollectorManager<TotalHitCountCollector, ReduceableSearchResult>,
+        EarlyTerminatingListener {
+
+    private static final TotalHitCountCollector EMPTY_COLLECTOR = new TotalHitCountCollector() {
+        @Override
+        public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
+            return new LeafCollector() {
+                @Override
+                public void setScorer(Scorable scorer) throws IOException {}
+
+                @Override
+                public void collect(int doc) throws IOException {}
+            };
+        }
+
+        @Override
+        public ScoreMode scoreMode() {
+            return ScoreMode.COMPLETE_NO_SCORES;
+        }
+    };
+
+    private final Sort sort;
+    private Integer terminatedAfter;
+
+    public TotalHitCountCollectorManager(final Sort sort) {
+        this.sort = sort;
+    }
+
+    @Override
+    public void onEarlyTermination(int maxCountHits, boolean forcedTermination) {
+        terminatedAfter = maxCountHits;
+    }
+
+    @Override
+    public TotalHitCountCollector newCollector() throws IOException {
+        return new TotalHitCountCollector();
+    }
+
+    @Override
+    public ReduceableSearchResult reduce(Collection<TotalHitCountCollector> collectors) throws IOException {
+        return (QuerySearchResult result) -> {
+            final TotalHits.Relation relation = (terminatedAfter != null)
+                ? TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO
+                : TotalHits.Relation.EQUAL_TO;
+
+            int totalHits = collectors.stream().mapToInt(TotalHitCountCollector::getTotalHits).sum();
+            if (terminatedAfter != null && totalHits > terminatedAfter) {
+                totalHits = terminatedAfter;
+            }
+
+            final TotalHits totalHitCount = new TotalHits(totalHits, relation);
+            final TopDocs topDocs = (sort != null)
+                ? new TopFieldDocs(totalHitCount, Lucene.EMPTY_SCORE_DOCS, sort.getSort())
+                : new TopDocs(totalHitCount, Lucene.EMPTY_SCORE_DOCS);
+
+            result.topDocs(new TopDocsAndMaxScore(topDocs, Float.NaN), null);
+        };
+    }
+
+    static class Empty implements CollectorManager<TotalHitCountCollector, ReduceableSearchResult> {
+        private final TotalHits totalHits;
+        private final Sort sort;
+
+        Empty(final TotalHits totalHits, final Sort sort) {
+            this.totalHits = totalHits;
+            this.sort = sort;
+        }
+
+        @Override
+        public TotalHitCountCollector newCollector() throws IOException {
+            return EMPTY_COLLECTOR;
+        }
+
+        @Override
+        public ReduceableSearchResult reduce(Collection<TotalHitCountCollector> collectors) throws IOException {
+            return (QuerySearchResult result) -> {
+                final TopDocs topDocs;
+
+                if (sort != null) {
+                    topDocs = new TopFieldDocs(totalHits, Lucene.EMPTY_SCORE_DOCS, sort.getSort());
+                } else {
+                    topDocs = new TopDocs(totalHits, Lucene.EMPTY_SCORE_DOCS);
+                }
+
+                result.topDocs(new TopDocsAndMaxScore(topDocs, Float.NaN), null);
+            };
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/query/package-info.java b/server/src/main/java/org/opensearch/search/query/package-info.java
new file mode 100644
index 0000000000000..f0d4b039fe192
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/query/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Query Listeners package. */
+package org.opensearch.search.query;
diff --git a/server/src/main/java/org/opensearch/search/rescore/QueryRescoreMode.java b/server/src/main/java/org/opensearch/search/rescore/QueryRescoreMode.java
index 748738b688c7f..17a20f8dab198 100644
--- a/server/src/main/java/org/opensearch/search/rescore/QueryRescoreMode.java
+++ b/server/src/main/java/org/opensearch/search/rescore/QueryRescoreMode.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.search.rescore;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 
+/**
+ * What mode the rescorer should operate in
+ *
+ * @opensearch.internal
+ */
 public enum QueryRescoreMode implements Writeable {
     Avg {
         @Override
diff --git a/server/src/main/java/org/opensearch/search/rescore/QueryRescorer.java b/server/src/main/java/org/opensearch/search/rescore/QueryRescorer.java
index a610881e39ca9..008bff18cea5b 100644
--- a/server/src/main/java/org/opensearch/search/rescore/QueryRescorer.java
+++ b/server/src/main/java/org/opensearch/search/rescore/QueryRescorer.java
@@ -47,6 +47,12 @@
 
 import static java.util.stream.Collectors.toSet;
 
+/**
+ * A concrete query rescorer used to re-rank the Top-K results of a previously
+ * executed search.
+ *
+ * @opensearch.internal
+ */
 public final class QueryRescorer implements Rescorer {
 
     public static final Rescorer INSTANCE = new QueryRescorer();
@@ -178,6 +184,11 @@ private TopDocs combine(TopDocs in, TopDocs resorted, QueryRescoreContext ctx) {
         return in;
     }
 
+    /**
+     * Context used during query rescoring
+     *
+     * @opensearch.internal
+     */
     public static class QueryRescoreContext extends RescoreContext {
         private Query query;
         private float queryWeight = 1.0f;
diff --git a/server/src/main/java/org/opensearch/search/rescore/QueryRescorerBuilder.java b/server/src/main/java/org/opensearch/search/rescore/QueryRescorerBuilder.java
index 39ca06caaab7d..aea10755d4e42 100644
--- a/server/src/main/java/org/opensearch/search/rescore/QueryRescorerBuilder.java
+++ b/server/src/main/java/org/opensearch/search/rescore/QueryRescorerBuilder.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.rescore;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -50,6 +50,11 @@
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * Builds a query rescorer object
+ *
+ * @opensearch.internal
+ */
 public class QueryRescorerBuilder extends RescorerBuilder<QueryRescorerBuilder> {
     public static final String NAME = "query";
 
diff --git a/server/src/main/java/org/opensearch/search/rescore/RescoreContext.java b/server/src/main/java/org/opensearch/search/rescore/RescoreContext.java
index 8c9b63d17e5d1..c0e4bbb874531 100644
--- a/server/src/main/java/org/opensearch/search/rescore/RescoreContext.java
+++ b/server/src/main/java/org/opensearch/search/rescore/RescoreContext.java
@@ -42,6 +42,8 @@
  * Context available to the rescore while it is running. Rescore
  * implementations should extend this with any additional resources that
  * they will need while rescoring.
+ *
+ * @opensearch.internal
  */
 public class RescoreContext {
     private final int windowSize;
diff --git a/server/src/main/java/org/opensearch/search/rescore/RescorePhase.java b/server/src/main/java/org/opensearch/search/rescore/RescorePhase.java
deleted file mode 100644
index 2f01ac265447b..0000000000000
--- a/server/src/main/java/org/opensearch/search/rescore/RescorePhase.java
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.rescore;
-
-import org.apache.lucene.search.ScoreDoc;
-import org.apache.lucene.search.TopDocs;
-import org.opensearch.OpenSearchException;
-import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
-import org.opensearch.search.internal.SearchContext;
-
-import java.io.IOException;
-
-/**
- * Rescore phase of a search request, used to run potentially expensive scoring models against the top matching documents.
- */
-public class RescorePhase {
-
-    public void execute(SearchContext context) {
-        TopDocs topDocs = context.queryResult().topDocs().topDocs;
-        if (topDocs.scoreDocs.length == 0) {
-            return;
-        }
-        try {
-            for (RescoreContext ctx : context.rescore()) {
-                topDocs = ctx.rescorer().rescore(topDocs, context.searcher(), ctx);
-                // It is the responsibility of the rescorer to sort the resulted top docs,
-                // here we only assert that this condition is met.
-                assert context.sort() == null && topDocsSortedByScore(topDocs) : "topdocs should be sorted after rescore";
-            }
-            context.queryResult()
-                .topDocs(new TopDocsAndMaxScore(topDocs, topDocs.scoreDocs[0].score), context.queryResult().sortValueFormats());
-        } catch (IOException e) {
-            throw new OpenSearchException("Rescore Phase Failed", e);
-        }
-    }
-
-    /**
-     * Returns true if the provided docs are sorted by score.
-     */
-    private boolean topDocsSortedByScore(TopDocs topDocs) {
-        if (topDocs == null || topDocs.scoreDocs == null || topDocs.scoreDocs.length < 2) {
-            return true;
-        }
-        float lastScore = topDocs.scoreDocs[0].score;
-        for (int i = 1; i < topDocs.scoreDocs.length; i++) {
-            ScoreDoc doc = topDocs.scoreDocs[i];
-            if (Float.compare(doc.score, lastScore) > 0) {
-                return false;
-            }
-            lastScore = doc.score;
-        }
-        return true;
-    }
-}
diff --git a/server/src/main/java/org/opensearch/search/rescore/RescoreProcessor.java b/server/src/main/java/org/opensearch/search/rescore/RescoreProcessor.java
new file mode 100644
index 0000000000000..de886ba9f8419
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/rescore/RescoreProcessor.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.rescore;
+
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.TopDocs;
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+import org.opensearch.search.internal.SearchContext;
+
+import java.io.IOException;
+
+/**
+ * RescoreProcessor of a search request, used to run potentially expensive scoring models against the top matching documents.
+ *
+ * @opensearch.internal
+ */
+public class RescoreProcessor {
+
+    public void process(SearchContext context) {
+        TopDocs topDocs = context.queryResult().topDocs().topDocs;
+        if (topDocs.scoreDocs.length == 0) {
+            return;
+        }
+        try {
+            for (RescoreContext ctx : context.rescore()) {
+                topDocs = ctx.rescorer().rescore(topDocs, context.searcher(), ctx);
+                // It is the responsibility of the rescorer to sort the resulted top docs,
+                // here we only assert that this condition is met.
+                assert context.sort() == null && topDocsSortedByScore(topDocs) : "topdocs should be sorted after rescore";
+            }
+            context.queryResult()
+                .topDocs(new TopDocsAndMaxScore(topDocs, topDocs.scoreDocs[0].score), context.queryResult().sortValueFormats());
+        } catch (IOException e) {
+            throw new OpenSearchException("Rescore Phase Failed", e);
+        }
+    }
+
+    /**
+     * Returns true if the provided docs are sorted by score.
+     */
+    private boolean topDocsSortedByScore(TopDocs topDocs) {
+        if (topDocs == null || topDocs.scoreDocs == null || topDocs.scoreDocs.length < 2) {
+            return true;
+        }
+        float lastScore = topDocs.scoreDocs[0].score;
+        for (int i = 1; i < topDocs.scoreDocs.length; i++) {
+            ScoreDoc doc = topDocs.scoreDocs[i];
+            if (Float.compare(doc.score, lastScore) > 0) {
+                return false;
+            }
+            lastScore = doc.score;
+        }
+        return true;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/rescore/Rescorer.java b/server/src/main/java/org/opensearch/search/rescore/Rescorer.java
index 128f0d3ae4eec..33f8e5e7b535d 100644
--- a/server/src/main/java/org/opensearch/search/rescore/Rescorer.java
+++ b/server/src/main/java/org/opensearch/search/rescore/Rescorer.java
@@ -45,6 +45,8 @@
  * Subclasses should borrow heavily from {@link QueryRescorer} because it is
  * fairly well behaved and documents that tradeoffs that it is making. There
  * is also an {@code ExampleRescorer} that is worth looking at.
+ *
+ * @opensearch.internal
  */
 public interface Rescorer {
     /**
diff --git a/server/src/main/java/org/opensearch/search/rescore/RescorerBuilder.java b/server/src/main/java/org/opensearch/search/rescore/RescorerBuilder.java
index 4eae1386aa25e..383771306ba7b 100644
--- a/server/src/main/java/org/opensearch/search/rescore/RescorerBuilder.java
+++ b/server/src/main/java/org/opensearch/search/rescore/RescorerBuilder.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.search.rescore;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.Rewriteable;
 
@@ -49,6 +50,8 @@
 
 /**
  * The abstract base builder for instances of {@link RescorerBuilder}.
+ *
+ * @opensearch.internal
  */
 public abstract class RescorerBuilder<RB extends RescorerBuilder<RB>>
     implements
@@ -167,6 +170,6 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/rescore/package-info.java b/server/src/main/java/org/opensearch/search/rescore/package-info.java
new file mode 100644
index 0000000000000..623f8ece8d24a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/rescore/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Query rescorer package. */
+package org.opensearch.search.rescore;
diff --git a/server/src/main/java/org/opensearch/search/searchafter/SearchAfterBuilder.java b/server/src/main/java/org/opensearch/search/searchafter/SearchAfterBuilder.java
index 45413ad45b1a3..a45b2bd40c03d 100644
--- a/server/src/main/java/org/opensearch/search/searchafter/SearchAfterBuilder.java
+++ b/server/src/main/java/org/opensearch/search/searchafter/SearchAfterBuilder.java
@@ -37,17 +37,16 @@
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSortField;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.sort.SortAndFormats;
@@ -59,6 +58,11 @@
 import java.util.List;
 import java.util.Objects;
 
+/**
+ * Builds a search after object
+ *
+ * @opensearch.internal
+ */
 public class SearchAfterBuilder implements ToXContentObject, Writeable {
     public static final ParseField SEARCH_AFTER = new ParseField("search_after");
     private static final Object[] EMPTY_SORT_VALUES = new Object[0];
@@ -196,9 +200,15 @@ private static Object convertValueFromSortType(String fieldName, SortField.Type
 
                 case LONG:
                     // for unsigned_long field type we want to pass search_after value through formatting
-                    if (value instanceof Number && format != DocValueFormat.UNSIGNED_LONG_SHIFTED) {
+                    if (value instanceof Number
+                        && (format != DocValueFormat.UNSIGNED_LONG_SHIFTED && format != DocValueFormat.UNSIGNED_LONG)) {
                         return ((Number) value).longValue();
+                    } else if (format == DocValueFormat.UNSIGNED_LONG_SHIFTED || format == DocValueFormat.UNSIGNED_LONG) {
+                        return format.parseUnsignedLong(value.toString(), false, () -> {
+                            throw new IllegalStateException("now() is not allowed in [search_after] key");
+                        });
                     }
+
                     return format.parseLong(
                         value.toString(),
                         false,
@@ -332,7 +342,7 @@ public String toString() {
             XContentBuilder builder = XContentFactory.jsonBuilder();
             builder.prettyPrint();
             toXContent(builder, EMPTY_PARAMS);
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (Exception e) {
             throw new OpenSearchException("Failed to build xcontent.", e);
         }
diff --git a/server/src/main/java/org/opensearch/search/searchafter/package-info.java b/server/src/main/java/org/opensearch/search/searchafter/package-info.java
new file mode 100644
index 0000000000000..a4f14a3e6cc23
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/searchafter/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base search after package. */
+package org.opensearch.search.searchafter;
diff --git a/server/src/main/java/org/opensearch/search/slice/DocValuesSliceQuery.java b/server/src/main/java/org/opensearch/search/slice/DocValuesSliceQuery.java
index 7ffe89250d313..d7d554c058c37 100644
--- a/server/src/main/java/org/opensearch/search/slice/DocValuesSliceQuery.java
+++ b/server/src/main/java/org/opensearch/search/slice/DocValuesSliceQuery.java
@@ -32,9 +32,8 @@
 
 package org.opensearch.search.slice;
 
-import com.carrotsearch.hppc.BitMixer;
-import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.DocValues;
+import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.ConstantScoreScorer;
 import org.apache.lucene.search.ConstantScoreWeight;
@@ -44,6 +43,7 @@
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.TwoPhaseIterator;
 import org.apache.lucene.search.Weight;
+import org.opensearch.common.util.BitMixer;
 
 import java.io.IOException;
 
@@ -52,6 +52,8 @@
  *
  * <b>NOTE</b>: With deterministic field values this query can be used across different readers safely.
  * If updates are accepted on the field you must ensure that the same reader is used for all `slice` queries.
+ *
+ * @opensearch.internal
  */
 public final class DocValuesSliceQuery extends SliceQuery {
     public DocValuesSliceQuery(String field, int id, int max) {
diff --git a/server/src/main/java/org/opensearch/search/slice/SliceBuilder.java b/server/src/main/java/org/opensearch/search/slice/SliceBuilder.java
index 9a9444927ae5f..71e137052f1dd 100644
--- a/server/src/main/java/org/opensearch/search/slice/SliceBuilder.java
+++ b/server/src/main/java/org/opensearch/search/slice/SliceBuilder.java
@@ -41,17 +41,18 @@
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.mapper.IdFieldMapper;
@@ -75,6 +76,8 @@
  *  (instead of {@code numShards*numSlices}).
  *  Otherwise the provided field must be a numeric and doc_values must be enabled. In that case a
  *  {@link org.opensearch.search.slice.DocValuesSliceQuery} is used to filter the results.
+ *
+ *  @opensearch.internal
  */
 public class SliceBuilder implements Writeable, ToXContentObject {
 
@@ -335,6 +338,6 @@ private GroupShardsIterator<ShardIterator> buildShardIterator(ClusterService clu
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/slice/SliceQuery.java b/server/src/main/java/org/opensearch/search/slice/SliceQuery.java
index 5b2c97e44a521..9b30b4e854de7 100644
--- a/server/src/main/java/org/opensearch/search/slice/SliceQuery.java
+++ b/server/src/main/java/org/opensearch/search/slice/SliceQuery.java
@@ -39,6 +39,8 @@
 
 /**
  * An abstract {@link Query} that defines an hash function to partition the documents in multiple slices.
+ *
+ * @opensearch.internal
  */
 public abstract class SliceQuery extends Query {
     private final String field;
diff --git a/server/src/main/java/org/opensearch/search/slice/TermsSliceQuery.java b/server/src/main/java/org/opensearch/search/slice/TermsSliceQuery.java
index 4a7b19701fecd..297020fe2fe4d 100644
--- a/server/src/main/java/org/opensearch/search/slice/TermsSliceQuery.java
+++ b/server/src/main/java/org/opensearch/search/slice/TermsSliceQuery.java
@@ -32,19 +32,19 @@
 
 package org.opensearch.search.slice;
 
-import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
-import org.apache.lucene.index.PostingsEnum;
-import org.apache.lucene.search.IndexSearcher;
-import org.apache.lucene.search.ScoreMode;
+import org.apache.lucene.search.ConstantScoreScorer;
+import org.apache.lucene.search.ConstantScoreWeight;
 import org.apache.lucene.search.DocIdSet;
 import org.apache.lucene.search.DocIdSetIterator;
-import org.apache.lucene.search.Weight;
-import org.apache.lucene.search.ConstantScoreWeight;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
-import org.apache.lucene.search.ConstantScoreScorer;
+import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.DocIdSetBuilder;
 import org.apache.lucene.util.StringHelper;
@@ -59,6 +59,8 @@
  * For each segment this filter enumerates the terms dictionary, computes the hash code for each term and fills
  * a bit set with the documents of all terms whose hash code matches the predicate.
  * <b>NOTE</b>: Documents with no value for that field are ignored.
+ *
+ * @opensearch.internal
  */
 public final class TermsSliceQuery extends SliceQuery {
     // Fixed seed for computing term hashCode
diff --git a/server/src/main/java/org/opensearch/search/slice/package-info.java b/server/src/main/java/org/opensearch/search/slice/package-info.java
new file mode 100644
index 0000000000000..b24c5ff7416a6
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/slice/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base slice query package. */
+package org.opensearch.search.slice;
diff --git a/server/src/main/java/org/opensearch/search/sort/BucketedSort.java b/server/src/main/java/org/opensearch/search/sort/BucketedSort.java
index 848b8c2d21252..3dd682eb841dc 100644
--- a/server/src/main/java/org/opensearch/search/sort/BucketedSort.java
+++ b/server/src/main/java/org/opensearch/search/sort/BucketedSort.java
@@ -37,12 +37,13 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.lucene.ScorerAware;
-import org.opensearch.common.util.BigArray;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.BitArray;
 import org.opensearch.common.util.DoubleArray;
 import org.opensearch.common.util.FloatArray;
+import org.opensearch.common.util.IntArray;
 import org.opensearch.common.util.LongArray;
+import org.opensearch.core.common.util.BigArray;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
@@ -92,10 +93,14 @@
  * (like {@link BigArrays#overSize(long)}) to get amortized linear number
  * of allocations and to play well with our paged arrays.
  * </p>
+ *
+ * @opensearch.internal
  */
 public abstract class BucketedSort implements Releasable {
     /**
      * Callbacks for storing extra data along with competitive sorts.
+     *
+     * @opensearch.internal
      */
     public interface ExtraData {
         /**
@@ -113,6 +118,11 @@ public interface ExtraData {
          */
         Loader loader(LeafReaderContext ctx) throws IOException;
 
+        /**
+         * Loader for extra data
+         *
+         * @opensearch.internal
+         */
         @FunctionalInterface
         interface Loader {
             /**
@@ -183,6 +193,8 @@ public int getBucketSize() {
     /**
      * Used with {@link BucketedSort#getValues(long, ResultBuilder)} to
      * build results from the sorting operation.
+     *
+     * @opensearch.internal
      */
     @FunctionalInterface
     public interface ResultBuilder<T> {
@@ -530,6 +542,11 @@ protected final void swap(long lhs, long rhs) {
             values.set(rhs, tmp);
         }
 
+        /**
+         * Leaf for doubles
+         *
+         * @opensearch.internal
+         */
         protected abstract class Leaf extends BucketedSort.Leaf {
             protected Leaf(LeafReaderContext ctx) {
                 super(ctx);
@@ -623,6 +640,11 @@ protected final void swap(long lhs, long rhs) {
             values.set(rhs, tmp);
         }
 
+        /**
+         * Leaf for floats
+         *
+         * @opensearch.internal
+         */
         protected abstract class Leaf extends BucketedSort.Leaf {
             protected Leaf(LeafReaderContext ctx) {
                 super(ctx);
@@ -702,6 +724,11 @@ protected final void swap(long lhs, long rhs) {
             values.set(rhs, tmp);
         }
 
+        /**
+         * Leaf for bucketed sort
+         *
+         * @opensearch.internal
+         */
         protected abstract class Leaf extends BucketedSort.Leaf {
             protected Leaf(LeafReaderContext ctx) {
                 super(ctx);
@@ -730,4 +757,178 @@ protected final boolean docBetterThan(long index) {
             }
         }
     }
+
+    /**
+     * Superclass for implementations of {@linkplain BucketedSort} for {@code int} keys.
+     */
+    public abstract static class ForInts extends BucketedSort {
+        private IntArray values = bigArrays.newIntArray(1, false);
+
+        public ForInts(BigArrays bigArrays, SortOrder sortOrder, DocValueFormat format, int bucketSize, ExtraData extra) {
+            super(bigArrays, sortOrder, format, bucketSize, extra);
+            initGatherOffsets();
+        }
+
+        @Override
+        public final boolean needsScores() {
+            return false;
+        }
+
+        @Override
+        protected final BigArray values() {
+            return values;
+        }
+
+        @Override
+        protected final void growValues(long minSize) {
+            values = bigArrays.grow(values, minSize);
+        }
+
+        @Override
+        protected final int getNextGatherOffset(long rootIndex) {
+            return values.get(rootIndex);
+        }
+
+        @Override
+        protected final void setNextGatherOffset(long rootIndex, int offset) {
+            values.set(rootIndex, offset);
+        }
+
+        @Override
+        protected final SortValue getValue(long index) {
+            return SortValue.from(values.get(index));
+        }
+
+        @Override
+        protected final boolean betterThan(long lhs, long rhs) {
+            return getOrder().reverseMul() * Integer.compare(values.get(lhs), values.get(rhs)) < 0;
+        }
+
+        @Override
+        protected final void swap(long lhs, long rhs) {
+            int tmp = values.get(lhs);
+            values.set(lhs, values.get(rhs));
+            values.set(rhs, tmp);
+        }
+
+        /**
+         * Leaf for bucketed sort
+         *
+         * @opensearch.internal
+         */
+        protected abstract class Leaf extends BucketedSort.Leaf {
+            protected Leaf(LeafReaderContext ctx) {
+                super(ctx);
+            }
+
+            /**
+             * Return the value for of this sort for the document to which
+             * we just {@link #advanceExact(int) moved}. This should be fast
+             * because it is called twice per competitive hit when in heap
+             * mode, once for {@link #docBetterThan(long)} and once
+             * for {@link #setIndexToDocValue(long)}.
+             */
+            protected abstract int docValue();
+
+            @Override
+            public final void setScorer(Scorable scorer) {}
+
+            @Override
+            protected final void setIndexToDocValue(long index) {
+                values.set(index, docValue());
+            }
+
+            @Override
+            protected final boolean docBetterThan(long index) {
+                return getOrder().reverseMul() * Integer.compare(docValue(), values.get(index)) < 0;
+            }
+        }
+    }
+
+    /**
+     * Superclass for implementations of {@linkplain BucketedSort} for {@code unsigned long} keys.
+     */
+    public abstract static class ForUnsignedLongs extends BucketedSort {
+        private LongArray values = bigArrays.newLongArray(1, false);
+
+        public ForUnsignedLongs(BigArrays bigArrays, SortOrder sortOrder, DocValueFormat format, int bucketSize, ExtraData extra) {
+            super(bigArrays, sortOrder, format, bucketSize, extra);
+            initGatherOffsets();
+        }
+
+        @Override
+        public final boolean needsScores() {
+            return false;
+        }
+
+        @Override
+        protected final BigArray values() {
+            return values;
+        }
+
+        @Override
+        protected final void growValues(long minSize) {
+            values = bigArrays.grow(values, minSize);
+        }
+
+        @Override
+        protected final int getNextGatherOffset(long rootIndex) {
+            return (int) values.get(rootIndex);
+        }
+
+        @Override
+        protected final void setNextGatherOffset(long rootIndex, int offset) {
+            values.set(rootIndex, offset);
+        }
+
+        @Override
+        protected final SortValue getValue(long index) {
+            return SortValue.fromUnsigned(values.get(index));
+        }
+
+        @Override
+        protected final boolean betterThan(long lhs, long rhs) {
+            return getOrder().reverseMul() * Long.compareUnsigned(values.get(lhs), values.get(rhs)) < 0;
+        }
+
+        @Override
+        protected final void swap(long lhs, long rhs) {
+            long tmp = values.get(lhs);
+            values.set(lhs, values.get(rhs));
+            values.set(rhs, tmp);
+        }
+
+        /**
+         * Leaf for bucketed sort
+         *
+         * @opensearch.internal
+         */
+        protected abstract class Leaf extends BucketedSort.Leaf {
+            protected Leaf(LeafReaderContext ctx) {
+                super(ctx);
+            }
+
+            /**
+             * Return the value for of this sort for the document to which
+             * we just {@link #advanceExact(int) moved}. This should be fast
+             * because it is called twice per competitive hit when in heap
+             * mode, once for {@link #docBetterThan(long)} and once
+             * for {@link #setIndexToDocValue(long)}.
+             */
+            protected abstract long docValue();
+
+            @Override
+            public final void setScorer(Scorable scorer) {}
+
+            @Override
+            protected final void setIndexToDocValue(long index) {
+                values.set(index, docValue());
+            }
+
+            @Override
+            protected final boolean docBetterThan(long index) {
+                return getOrder().reverseMul() * Long.compareUnsigned(docValue(), values.get(index)) < 0;
+            }
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/sort/FieldSortBuilder.java b/server/src/main/java/org/opensearch/search/sort/FieldSortBuilder.java
index d4a3b8651e7a1..8403a65111307 100644
--- a/server/src/main/java/org/opensearch/search/sort/FieldSortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/FieldSortBuilder.java
@@ -34,23 +34,25 @@
 
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.MultiTerms;
 import org.apache.lucene.index.PointValues;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.search.SortField;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.time.DateUtils;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSortConfig;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
@@ -70,6 +72,7 @@
 import org.opensearch.search.builder.SearchSourceBuilder;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Collections;
 import java.util.Locale;
 import java.util.Objects;
@@ -81,6 +84,8 @@
 
 /**
  * A sort builder to sort based on a document field.
+ *
+ * @opensearch.internal
  */
 public class FieldSortBuilder extends SortBuilder<FieldSortBuilder> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(FieldSortBuilder.class);
@@ -389,6 +394,8 @@ private static NumericType resolveNumericType(String value) {
                 return NumericType.DATE;
             case "date_nanos":
                 return NumericType.DATE_NANOSECONDS;
+            case "unsigned_long":
+                return NumericType.UNSIGNED_LONG;
 
             default:
                 throw new IllegalArgumentException(
@@ -604,17 +611,31 @@ public static FieldSortBuilder getPrimaryFieldSortOrNull(SearchSourceBuilder sou
     }
 
     /**
-     * Return the {@link MinAndMax} indexed value from the provided {@link FieldSortBuilder} or <code>null</code> if unknown.
+     * Return the {@link MinAndMax} indexed value for shard from the provided {@link FieldSortBuilder} or <code>null</code> if unknown.
      * The value can be extracted on non-nested indexed mapped fields of type keyword, numeric or date, other fields
      * and configurations return <code>null</code>.
      */
     public static MinAndMax<?> getMinMaxOrNull(QueryShardContext context, FieldSortBuilder sortBuilder) throws IOException {
+        return getMinMaxOrNullInternal(context.getIndexReader(), context, sortBuilder);
+    }
+
+    /**
+     * Return the {@link MinAndMax} indexed value for segment from the provided {@link FieldSortBuilder} or <code>null</code> if unknown.
+     * The value can be extracted on non-nested indexed mapped fields of type keyword, numeric or date, other fields
+     * and configurations return <code>null</code>.
+     */
+    public static MinAndMax<?> getMinMaxOrNullForSegment(QueryShardContext context, LeafReaderContext ctx, FieldSortBuilder sortBuilder)
+        throws IOException {
+        return getMinMaxOrNullInternal(ctx.reader(), context, sortBuilder);
+    }
+
+    private static MinAndMax<?> getMinMaxOrNullInternal(IndexReader reader, QueryShardContext context, FieldSortBuilder sortBuilder)
+        throws IOException {
         SortAndFormats sort = SortBuilder.buildSort(Collections.singletonList(sortBuilder), context).get();
         SortField sortField = sort.sort.getSort()[0];
         if (sortField.getField() == null) {
             return null;
         }
-        IndexReader reader = context.getIndexReader();
         MappedFieldType fieldType = context.fieldMapper(sortField.getField());
         if (reader == null || (fieldType == null || fieldType.isSearchable() == false)) {
             return null;
@@ -655,7 +676,12 @@ private static MinAndMax<?> extractNumericMinAndMax(
             Number maxPoint = numberFieldType.parsePoint(PointValues.getMaxPackedValue(reader, fieldName));
             switch (IndexSortConfig.getSortFieldType(sortField)) {
                 case LONG:
-                    return new MinAndMax<>(minPoint.longValue(), maxPoint.longValue());
+                    if (numberFieldType.numericType() == NumericType.UNSIGNED_LONG) {
+                        // The min and max are expected to be BigInteger numbers
+                        return new MinAndMax<>((BigInteger) minPoint, (BigInteger) maxPoint);
+                    } else {
+                        return new MinAndMax<>(minPoint.longValue(), maxPoint.longValue());
+                    }
                 case INT:
                     return new MinAndMax<>(minPoint.intValue(), maxPoint.intValue());
                 case DOUBLE:
@@ -742,7 +768,7 @@ public String getWriteableName() {
 
     /**
      * Creates a new {@link FieldSortBuilder} from the query held by the {@link XContentParser} in
-     * {@link org.opensearch.common.xcontent.XContent} format.
+     * {@link XContent} format.
      *
      * @param parser the input parser. The state on the parser contained in this context will be changed as a side effect of this
      *        method call
diff --git a/server/src/main/java/org/opensearch/search/sort/GeoDistanceSortBuilder.java b/server/src/main/java/org/opensearch/search/sort/GeoDistanceSortBuilder.java
index 2ab9703b45980..e5f0d7e75afd5 100644
--- a/server/src/main/java/org/opensearch/search/sort/GeoDistanceSortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/GeoDistanceSortBuilder.java
@@ -42,19 +42,20 @@
 import org.apache.lucene.search.comparators.DoubleComparator;
 import org.apache.lucene.util.BitSet;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
@@ -84,6 +85,8 @@
 
 /**
  * A geo distance based sorting on a geo point like field.
+ *
+ * @opensearch.internal
  */
 public class GeoDistanceSortBuilder extends SortBuilder<GeoDistanceSortBuilder> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(GeoDistanceSortBuilder.class);
@@ -473,7 +476,7 @@ public int hashCode() {
 
     /**
      * Creates a new {@link GeoDistanceSortBuilder} from the query held by the {@link XContentParser} in
-     * {@link org.opensearch.common.xcontent.XContent} format.
+     * {@link XContent} format.
      *
      * @param parser the input parser. The state on the parser contained in this context will be changed as a
      *                side effect of this method call
diff --git a/server/src/main/java/org/opensearch/search/sort/MinAndMax.java b/server/src/main/java/org/opensearch/search/sort/MinAndMax.java
index bae4ad1bda353..98213ec630e33 100644
--- a/server/src/main/java/org/opensearch/search/sort/MinAndMax.java
+++ b/server/src/main/java/org/opensearch/search/sort/MinAndMax.java
@@ -32,17 +32,21 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.lucene.Lucene;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.Comparator;
 import java.util.Objects;
 
 /**
  * A class that encapsulates a minimum and a maximum, that are of the same type and {@link Comparable}.
+ *
+ * @opensearch.internal
  */
 public class MinAndMax<T extends Comparable<? super T>> implements Writeable {
     private final T minValue;
@@ -91,4 +95,36 @@ public static Comparator<MinAndMax<?>> getComparator(SortOrder order) {
         }
         return Comparator.nullsLast(cmp);
     }
+
+    /**
+     * Compare given object with min
+     */
+    public int compareMin(Object object) {
+        return compare(getMin(), object);
+    }
+
+    /**
+     * Compare given object with max
+     */
+    public int compareMax(Object object) {
+        return compare(getMax(), object);
+    }
+
+    private int compare(T one, Object two) {
+        if (one instanceof Long) {
+            return Long.compare((Long) one, (Long) two);
+        } else if (one instanceof Integer) {
+            return Integer.compare((Integer) one, (Integer) two);
+        } else if (one instanceof Float) {
+            return Float.compare((Float) one, (Float) two);
+        } else if (one instanceof Double) {
+            return Double.compare((Double) one, (Double) two);
+        } else if (one instanceof BigInteger) {
+            return ((BigInteger) one).compareTo((BigInteger) two);
+        } else if (one instanceof BytesRef) {
+            return ((BytesRef) one).compareTo((BytesRef) two);
+        } else {
+            throw new UnsupportedOperationException("compare type not supported : " + one.getClass());
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/sort/NestedSortBuilder.java b/server/src/main/java/org/opensearch/search/sort/NestedSortBuilder.java
index 2463cb9294911..feabdfce4cd21 100644
--- a/server/src/main/java/org/opensearch/search/sort/NestedSortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/NestedSortBuilder.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 
@@ -47,6 +47,11 @@
 
 import static org.opensearch.search.sort.SortBuilder.parseNestedFilter;
 
+/**
+ * Builds a sort on nested objects
+ *
+ * @opensearch.internal
+ */
 public class NestedSortBuilder implements Writeable, ToXContentObject {
     public static final ParseField NESTED_FIELD = new ParseField("nested");
     public static final ParseField PATH_FIELD = new ParseField("path");
diff --git a/server/src/main/java/org/opensearch/search/sort/ScoreSortBuilder.java b/server/src/main/java/org/opensearch/search/sort/ScoreSortBuilder.java
index d0dab54bf8f68..1be49e5ca81ce 100644
--- a/server/src/main/java/org/opensearch/search/sort/ScoreSortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/ScoreSortBuilder.java
@@ -35,11 +35,12 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.SortField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.DocValueFormat;
@@ -49,6 +50,8 @@
 
 /**
  * A sort builder allowing to sort by score.
+ *
+ * @opensearch.internal
  */
 public class ScoreSortBuilder extends SortBuilder<ScoreSortBuilder> {
 
@@ -94,7 +97,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     /**
      * Creates a new {@link ScoreSortBuilder} from the query held by the {@link XContentParser} in
-     * {@link org.opensearch.common.xcontent.XContent} format.
+     * {@link XContent} format.
      *
      * @param parser the input parser. The state on the parser contained in this context will be changed as a side effect of this
      *        method call
diff --git a/server/src/main/java/org/opensearch/search/sort/ScriptSortBuilder.java b/server/src/main/java/org/opensearch/search/sort/ScriptSortBuilder.java
index 55a3f380b0e16..bb1930eb3a953 100644
--- a/server/src/main/java/org/opensearch/search/sort/ScriptSortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/ScriptSortBuilder.java
@@ -38,16 +38,17 @@
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser.ValueType;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser.ValueType;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.AbstractBinaryDocValues;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
@@ -68,15 +69,20 @@
 import org.opensearch.search.MultiValueMode;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.search.sort.FieldSortBuilder.validateMaxChildrenExistOnlyInTopLevelNestedSort;
 import static org.opensearch.search.sort.NestedSortBuilder.NESTED_FIELD;
 
 /**
  * Script sort builder allows to sort based on a custom script expression.
+ *
+ * @opensearch.internal
  */
 public class ScriptSortBuilder extends SortBuilder<ScriptSortBuilder> {
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(ScriptSortBuilder.class);
@@ -305,7 +311,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params builderParams)
 
     /**
      * Creates a new {@link ScriptSortBuilder} from the query held by the {@link XContentParser} in
-     * {@link org.opensearch.common.xcontent.XContent} format.
+     * {@link XContent} format.
      *
      * @param parser the input parser. The state on the parser contained in this context will be changed as a side effect of this
      *        method call
@@ -352,11 +358,19 @@ private IndexFieldData.XFieldComparatorSource fieldComparatorSource(QueryShardCo
                 final StringSortScript.Factory factory = context.compile(script, StringSortScript.CONTEXT);
                 final StringSortScript.LeafFactory searchScript = factory.newFactory(script.getParams(), context.lookup());
                 return new BytesRefFieldComparatorSource(null, null, valueMode, nested) {
-                    StringSortScript leafScript;
+                    // introducing a map to keep a mapping between the leaf reader context and leaf script
+                    // such that the functions of the class are thread safe in case of concurrent search
+                    final Map<LeafReaderContext, StringSortScript> leafContextSortScriptMap = new ConcurrentHashMap<>();
 
                     @Override
                     protected SortedBinaryDocValues getValues(LeafReaderContext context) throws IOException {
-                        leafScript = searchScript.newInstance(context);
+                        final StringSortScript leafScript = leafContextSortScriptMap.computeIfAbsent(context, ctx -> {
+                            try {
+                                return searchScript.newInstance(ctx);
+                            } catch (IOException e) {
+                                throw new UncheckedIOException(e);
+                            }
+                        });
                         final BinaryDocValues values = new AbstractBinaryDocValues() {
                             final BytesRefBuilder spare = new BytesRefBuilder();
 
@@ -376,8 +390,8 @@ public BytesRef binaryValue() {
                     }
 
                     @Override
-                    protected void setScorer(Scorable scorer) {
-                        leafScript.setScorer(scorer);
+                    protected void setScorer(Scorable scorer, LeafReaderContext context) {
+                        leafContextSortScriptMap.get(context).setScorer(scorer);
                     }
 
                     @Override
@@ -400,11 +414,19 @@ public BucketedSort newBucketedSort(
                 final NumberSortScript.Factory numberSortFactory = context.compile(script, NumberSortScript.CONTEXT);
                 final NumberSortScript.LeafFactory numberSortScript = numberSortFactory.newFactory(script.getParams(), context.lookup());
                 return new DoubleValuesComparatorSource(null, Double.MAX_VALUE, valueMode, nested) {
-                    NumberSortScript leafScript;
+                    // introducing a map to keep a mapping between the leaf reader context and leaf script
+                    // such that the functions of the class are thread safe in case of concurrent search
+                    final Map<LeafReaderContext, NumberSortScript> leafContextSortScriptMap = new ConcurrentHashMap<>();
 
                     @Override
                     protected SortedNumericDoubleValues getValues(LeafReaderContext context) throws IOException {
-                        leafScript = numberSortScript.newInstance(context);
+                        final NumberSortScript leafScript = leafContextSortScriptMap.computeIfAbsent(context, ctx -> {
+                            try {
+                                return numberSortScript.newInstance(ctx);
+                            } catch (IOException e) {
+                                throw new UncheckedIOException(e);
+                            }
+                        });
                         final NumericDoubleValues values = new NumericDoubleValues() {
                             @Override
                             public boolean advanceExact(int doc) throws IOException {
@@ -421,8 +443,8 @@ public double doubleValue() {
                     }
 
                     @Override
-                    protected void setScorer(Scorable scorer) {
-                        leafScript.setScorer(scorer);
+                    protected void setScorer(Scorable scorer, LeafReaderContext context) {
+                        leafContextSortScriptMap.get(context).setScorer(scorer);
                     }
                 };
             default:
@@ -458,6 +480,11 @@ public String getWriteableName() {
         return NAME;
     }
 
+    /**
+     * Sort type for scripting
+     *
+     * @opensearch.internal
+     */
     public enum ScriptSortType implements Writeable {
         /** script sort for a string value **/
         STRING,
diff --git a/server/src/main/java/org/opensearch/search/sort/SortAndFormats.java b/server/src/main/java/org/opensearch/search/sort/SortAndFormats.java
index e0abe94ff6e23..e65187e558aef 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortAndFormats.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortAndFormats.java
@@ -32,8 +32,14 @@
 package org.opensearch.search.sort;
 
 import org.apache.lucene.search.Sort;
+import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.search.DocValueFormat;
 
+/**
+ * Utility class to hold sort and doc value format instances
+ *
+ * @opensearch.internal
+ */
 public final class SortAndFormats {
 
     public final Sort sort;
@@ -47,4 +53,13 @@ public SortAndFormats(Sort sort, DocValueFormat[] formats) {
         this.formats = formats;
     }
 
+    /**
+     * @return true: if sort is on timestamp field, false: otherwise
+     */
+    public boolean isSortOnTimeSeriesField() {
+        return sort.getSort().length > 0
+            && sort.getSort()[0].getField() != null
+            && sort.getSort()[0].getField().equals(DataStream.TIMESERIES_FIELDNAME);
+    }
+
 }
diff --git a/server/src/main/java/org/opensearch/search/sort/SortBuilder.java b/server/src/main/java/org/opensearch/search/sort/SortBuilder.java
index 74a4d974c9555..4a20af63e273f 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortBuilder.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortBuilder.java
@@ -36,14 +36,15 @@
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.join.ToChildBlockJoinQuery;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
 import org.opensearch.common.lucene.search.Queries;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.mapper.ObjectMapper;
 import org.opensearch.index.query.QueryBuilder;
@@ -60,6 +61,11 @@
 
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 
+/**
+ * Base class for sort object builders
+ *
+ * @opensearch.internal
+ */
 public abstract class SortBuilder<T extends SortBuilder<T>> implements NamedWriteable, ToXContentObject, Rewriteable<SortBuilder<?>> {
 
     protected SortOrder order = SortOrder.ASC;
@@ -280,6 +286,6 @@ protected static QueryBuilder parseNestedFilter(XContentParser parser) {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/sort/SortBuilders.java b/server/src/main/java/org/opensearch/search/sort/SortBuilders.java
index dc535847257d7..209b5b160f30b 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortBuilders.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortBuilders.java
@@ -39,7 +39,7 @@
 /**
  * A set of static factory methods for {@link SortBuilder}s.
  *
- *
+ * @opensearch.internal
  */
 public class SortBuilders {
 
diff --git a/server/src/main/java/org/opensearch/search/sort/SortFieldAndFormat.java b/server/src/main/java/org/opensearch/search/sort/SortFieldAndFormat.java
index 8b0d0c1cd6775..4734e76317b01 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortFieldAndFormat.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortFieldAndFormat.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.search.sort;
 
-import java.util.Objects;
-
 import org.apache.lucene.search.SortField;
 import org.opensearch.search.DocValueFormat;
 
+import java.util.Objects;
+
+/**
+ * A holder for SortField and doc value format objects
+ *
+ * @opensearch.internal
+ */
 public final class SortFieldAndFormat {
 
     public final SortField field;
diff --git a/server/src/main/java/org/opensearch/search/sort/SortMode.java b/server/src/main/java/org/opensearch/search/sort/SortMode.java
index 6c63bfa702417..028b907ebe864 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortMode.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortMode.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -50,6 +50,8 @@
  * <li>avg - Use the average of all values as sort value. Only applicable for number based array fields.</li>
  * <li>median - Use the median of all values as sort value. Only applicable for number based array fields.</li>
  * </ul>
+ *
+ * @opensearch.internal
  */
 public enum SortMode implements Writeable {
     /** pick the lowest value **/
diff --git a/server/src/main/java/org/opensearch/search/sort/SortOrder.java b/server/src/main/java/org/opensearch/search/sort/SortOrder.java
index 290c2fdb413a5..ed83a0667c5e7 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortOrder.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortOrder.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Comparator;
@@ -43,7 +43,7 @@
 /**
  * A sorting order.
  *
- *
+ * @opensearch.internal
  */
 public enum SortOrder implements Writeable {
     /**
diff --git a/server/src/main/java/org/opensearch/search/sort/SortParser.java b/server/src/main/java/org/opensearch/search/sort/SortParser.java
index 870981c47382c..6a9d5c6093e1a 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortParser.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortParser.java
@@ -8,10 +8,15 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
+/**
+ * A base parser interface for creating sort objects based on API requests
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface SortParser<SB extends SortBuilder<SB>> {
     /**
diff --git a/server/src/main/java/org/opensearch/search/sort/SortValue.java b/server/src/main/java/org/opensearch/search/sort/SortValue.java
index 4d403afaf264e..0c46428bc02d0 100644
--- a/server/src/main/java/org/opensearch/search/sort/SortValue.java
+++ b/server/src/main/java/org/opensearch/search/sort/SortValue.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
@@ -45,6 +45,8 @@
 
 /**
  * A {@link Comparable}, {@link DocValueFormat} aware wrapper around a sort value.
+ *
+ * @opensearch.internal
  */
 public abstract class SortValue implements NamedWriteable, Comparable<SortValue> {
     /**
@@ -61,13 +63,21 @@ public static SortValue from(long l) {
         return new LongSortValue(l);
     }
 
+    /**
+     * Get a {@linkplain SortValue} for a unsigned long.
+     */
+    public static SortValue fromUnsigned(long l) {
+        return new UnsignedLongSortValue(l);
+    }
+
     /**
      * Get the list of {@linkplain NamedWriteable}s that this class needs.
      */
     public static List<NamedWriteableRegistry.Entry> namedWriteables() {
         return Arrays.asList(
             new NamedWriteableRegistry.Entry(SortValue.class, DoubleSortValue.NAME, DoubleSortValue::new),
-            new NamedWriteableRegistry.Entry(SortValue.class, LongSortValue.NAME, LongSortValue::new)
+            new NamedWriteableRegistry.Entry(SortValue.class, LongSortValue.NAME, LongSortValue::new),
+            new NamedWriteableRegistry.Entry(SortValue.class, UnsignedLongSortValue.NAME, UnsignedLongSortValue::new)
         );
     }
 
@@ -273,4 +283,73 @@ public Number numberValue() {
             return key;
         }
     }
+
+    private static class UnsignedLongSortValue extends SortValue {
+        public static final String NAME = "unsigned_long";
+
+        private final long key;
+
+        UnsignedLongSortValue(long key) {
+            this.key = key;
+        }
+
+        UnsignedLongSortValue(StreamInput in) throws IOException {
+            key = in.readLong();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeLong(key);
+        }
+
+        @Override
+        public String getWriteableName() {
+            return NAME;
+        }
+
+        @Override
+        public Object getKey() {
+            return key;
+        }
+
+        @Override
+        public String format(DocValueFormat format) {
+            return format.format(key).toString();
+        }
+
+        @Override
+        protected XContentBuilder rawToXContent(XContentBuilder builder) throws IOException {
+            return builder.value(key);
+        }
+
+        @Override
+        protected int compareToSameType(SortValue obj) {
+            UnsignedLongSortValue other = (UnsignedLongSortValue) obj;
+            return Long.compareUnsigned(key, other.key);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null || false == getClass().equals(obj.getClass())) {
+                return false;
+            }
+            UnsignedLongSortValue other = (UnsignedLongSortValue) obj;
+            return key == other.key;
+        }
+
+        @Override
+        public int hashCode() {
+            return Long.hashCode(key);
+        }
+
+        @Override
+        public String toString() {
+            return Long.toUnsignedString(key);
+        }
+
+        @Override
+        public Number numberValue() {
+            return key;
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/search/sort/SortedWiderNumericSortField.java b/server/src/main/java/org/opensearch/search/sort/SortedWiderNumericSortField.java
new file mode 100644
index 0000000000000..bded2417ba6c1
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/sort/SortedWiderNumericSortField.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.sort;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.FieldComparator;
+import org.apache.lucene.search.LeafFieldComparator;
+import org.apache.lucene.search.SortedNumericSortField;
+import org.apache.lucene.search.comparators.NumericComparator;
+
+import java.io.IOException;
+
+/**
+ * Sorted numeric field for wider sort types,
+ * to help sorting two different numeric types.
+ *
+ * @opensearch.internal
+ */
+public class SortedWiderNumericSortField extends SortedNumericSortField {
+    /**
+     * Creates a sort, possibly in reverse, specifying how the sort value from the document's set is
+     * selected.
+     *
+     * @param field    Name of field to sort by. Must not be null.
+     * @param type     Type of values
+     * @param reverse  True if natural order should be reversed.
+     */
+    public SortedWiderNumericSortField(String field, Type type, boolean reverse) {
+        super(field, type, reverse);
+    }
+
+    /**
+     * Creates and return a comparator, which always converts Numeric to double
+     * and compare to support multi type comparison between numeric values
+     * @param numHits number of top hits the queue will store
+     * @param enableSkipping true if the comparator can skip documents via {@link
+     *     LeafFieldComparator#competitiveIterator()}
+     * @return NumericComparator
+     */
+    @Override
+    public FieldComparator<?> getComparator(int numHits, boolean enableSkipping) {
+        return new NumericComparator<Number>(getField(), (Number) getMissingValue(), getReverse(), enableSkipping, Double.BYTES) {
+            @Override
+            public int compare(int slot1, int slot2) {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public Number value(int slot) {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public int compareValues(Number first, Number second) {
+                if (first == null) {
+                    if (second == null) {
+                        return 0;
+                    } else {
+                        return -1;
+                    }
+                } else if (second == null) {
+                    return 1;
+                } else {
+                    return Double.compare(first.doubleValue(), second.doubleValue());
+                }
+            }
+        };
+    }
+
+    /**
+     * The only below types would be considered for widening during merging topDocs results for sort,
+     * This will support indices having different Numeric types to be sorted together.
+     * @param type SortField.Type
+     * @return returns true if type is supported for widened numeric comparisons
+     */
+    public static boolean isTypeSupported(Type type) {
+        // Only below 4 numeric types supported as of now for widened merge
+        switch (type) {
+            case INT:
+            case LONG:
+            case FLOAT:
+            case DOUBLE:
+                return true;
+            default:
+                return false;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/search/sort/package-info.java b/server/src/main/java/org/opensearch/search/sort/package-info.java
new file mode 100644
index 0000000000000..2c83ef57a3a60
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/sort/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base sorting package. */
+package org.opensearch.search.sort;
diff --git a/server/src/main/java/org/opensearch/search/suggest/DirectSpellcheckerSettings.java b/server/src/main/java/org/opensearch/search/suggest/DirectSpellcheckerSettings.java
index 03821a90fbbec..d49953594847c 100644
--- a/server/src/main/java/org/opensearch/search/suggest/DirectSpellcheckerSettings.java
+++ b/server/src/main/java/org/opensearch/search/suggest/DirectSpellcheckerSettings.java
@@ -41,6 +41,11 @@
 
 import java.util.Comparator;
 
+/**
+ * Settings for the direct spell checker
+ *
+ * @opensearch.internal
+ */
 public class DirectSpellcheckerSettings {
 
     // NB: If this changes, make sure to change the default in TermBuilderSuggester
diff --git a/server/src/main/java/org/opensearch/search/suggest/SortBy.java b/server/src/main/java/org/opensearch/search/suggest/SortBy.java
index 39f825a98a9b7..5b2235b10317f 100644
--- a/server/src/main/java/org/opensearch/search/suggest/SortBy.java
+++ b/server/src/main/java/org/opensearch/search/suggest/SortBy.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -42,6 +42,8 @@
 
 /**
  * An enum representing the valid sorting options
+ *
+ * @opensearch.internal
  */
 public enum SortBy implements Writeable {
     /** Sort should first be based on score, then document frequency and then the term itself. */
diff --git a/server/src/main/java/org/opensearch/search/suggest/Suggest.java b/server/src/main/java/org/opensearch/search/suggest/Suggest.java
index 14ee4acdd11a9..89884fe030564 100644
--- a/server/src/main/java/org/opensearch/search/suggest/Suggest.java
+++ b/server/src/main/java/org/opensearch/search/suggest/Suggest.java
@@ -32,22 +32,23 @@
 package org.opensearch.search.suggest;
 
 import org.apache.lucene.util.CollectionUtil;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.suggest.Suggest.Suggestion.Entry;
@@ -67,10 +68,12 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 
 /**
  * Top level suggest result, containing the result for each suggestion.
+ *
+ * @opensearch.internal
  */
 public class Suggest implements Iterable<Suggest.Suggestion<? extends Entry<? extends Option>>>, Writeable, ToXContentFragment {
 
@@ -788,6 +791,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestBuilder.java b/server/src/main/java/org/opensearch/search/suggest/SuggestBuilder.java
index f0e9aabc1fcfd..0691a82299131 100644
--- a/server/src/main/java/org/opensearch/search/suggest/SuggestBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/SuggestBuilder.java
@@ -32,16 +32,17 @@
 package org.opensearch.search.suggest;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
 
@@ -57,6 +58,8 @@
  * <p>
  * Suggesting works by suggesting terms/phrases that appear in the suggest text that are similar compared
  * to the terms in provided text. These suggestions are based on several options described in this class.
+ *
+ * @opensearch.internal
  */
 public class SuggestBuilder implements Writeable, ToXContentObject {
     protected static final ParseField GLOBAL_TEXT_FIELD = new ParseField("text");
@@ -215,6 +218,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 }
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestBuilders.java b/server/src/main/java/org/opensearch/search/suggest/SuggestBuilders.java
index 7ce66862aefde..100b981b6194e 100644
--- a/server/src/main/java/org/opensearch/search/suggest/SuggestBuilders.java
+++ b/server/src/main/java/org/opensearch/search/suggest/SuggestBuilders.java
@@ -38,6 +38,8 @@
 
 /**
  * A static factory for building suggester lookup queries
+ *
+ * @opensearch.internal
  */
 public abstract class SuggestBuilders {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestPhase.java b/server/src/main/java/org/opensearch/search/suggest/SuggestPhase.java
deleted file mode 100644
index d2b2edf900b9d..0000000000000
--- a/server/src/main/java/org/opensearch/search/suggest/SuggestPhase.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.suggest;
-
-import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.OpenSearchException;
-import org.opensearch.search.internal.SearchContext;
-import org.opensearch.search.suggest.Suggest.Suggestion;
-import org.opensearch.search.suggest.Suggest.Suggestion.Entry;
-import org.opensearch.search.suggest.Suggest.Suggestion.Entry.Option;
-import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-
-/**
- * Suggest phase of a search request, used to collect suggestions
- */
-public class SuggestPhase {
-
-    public void execute(SearchContext context) {
-        final SuggestionSearchContext suggest = context.suggest();
-        if (suggest == null) {
-            return;
-        }
-        try {
-            CharsRefBuilder spare = new CharsRefBuilder();
-            final List<Suggestion<? extends Entry<? extends Option>>> suggestions = new ArrayList<>(suggest.suggestions().size());
-
-            for (Map.Entry<String, SuggestionSearchContext.SuggestionContext> entry : suggest.suggestions().entrySet()) {
-                SuggestionSearchContext.SuggestionContext suggestion = entry.getValue();
-                Suggester<SuggestionContext> suggester = suggestion.getSuggester();
-                Suggestion<? extends Entry<? extends Option>> result = suggester.execute(
-                    entry.getKey(),
-                    suggestion,
-                    context.searcher(),
-                    spare
-                );
-                if (result != null) {
-                    assert entry.getKey().equals(result.name);
-                    suggestions.add(result);
-                }
-            }
-            context.queryResult().suggest(new Suggest(suggestions));
-        } catch (IOException e) {
-            throw new OpenSearchException("I/O exception during suggest phase", e);
-        }
-    }
-
-}
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestProcessor.java b/server/src/main/java/org/opensearch/search/suggest/SuggestProcessor.java
new file mode 100644
index 0000000000000..2860959835176
--- /dev/null
+++ b/server/src/main/java/org/opensearch/search/suggest/SuggestProcessor.java
@@ -0,0 +1,83 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.suggest;
+
+import org.apache.lucene.util.CharsRefBuilder;
+import org.opensearch.OpenSearchException;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.suggest.Suggest.Suggestion;
+import org.opensearch.search.suggest.Suggest.Suggestion.Entry;
+import org.opensearch.search.suggest.Suggest.Suggestion.Entry.Option;
+import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * SuggestProcessor of a search request, used to collect suggestions
+ *
+ * @opensearch.internal
+ */
+public class SuggestProcessor {
+
+    public void process(SearchContext context) {
+        final SuggestionSearchContext suggest = context.suggest();
+        if (suggest == null) {
+            return;
+        }
+        try {
+            CharsRefBuilder spare = new CharsRefBuilder();
+            final List<Suggestion<? extends Entry<? extends Option>>> suggestions = new ArrayList<>(suggest.suggestions().size());
+
+            for (Map.Entry<String, SuggestionSearchContext.SuggestionContext> entry : suggest.suggestions().entrySet()) {
+                SuggestionSearchContext.SuggestionContext suggestion = entry.getValue();
+                Suggester<SuggestionContext> suggester = suggestion.getSuggester();
+                Suggestion<? extends Entry<? extends Option>> result = suggester.execute(
+                    entry.getKey(),
+                    suggestion,
+                    context.searcher(),
+                    spare
+                );
+                if (result != null) {
+                    assert entry.getKey().equals(result.name);
+                    suggestions.add(result);
+                }
+            }
+            context.queryResult().suggest(new Suggest(suggestions));
+        } catch (IOException e) {
+            throw new OpenSearchException("I/O exception during suggest phase", e);
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/search/suggest/Suggester.java b/server/src/main/java/org/opensearch/search/suggest/Suggester.java
index b1a12e20e4d62..29efc6c4a3a6a 100644
--- a/server/src/main/java/org/opensearch/search/suggest/Suggester.java
+++ b/server/src/main/java/org/opensearch/search/suggest/Suggester.java
@@ -37,6 +37,11 @@
 
 import java.io.IOException;
 
+/**
+ * Base class used for all suggester implementations
+ *
+ * @opensearch.internal
+ */
 public abstract class Suggester<T extends SuggestionSearchContext.SuggestionContext> {
 
     protected abstract Suggest.Suggestion<? extends Suggest.Suggestion.Entry<? extends Suggest.Suggestion.Entry.Option>> innerExecute(
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestionBuilder.java b/server/src/main/java/org/opensearch/search/suggest/SuggestionBuilder.java
index 60768cf3a0842..05574bbe06fa6 100644
--- a/server/src/main/java/org/opensearch/search/suggest/SuggestionBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/SuggestionBuilder.java
@@ -34,15 +34,15 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryShardContext;
@@ -53,6 +53,8 @@
 
 /**
  * Base class for the different suggestion implementations.
+ *
+ * @opensearch.internal
  */
 public abstract class SuggestionBuilder<T extends SuggestionBuilder<T>> implements NamedWriteable, ToXContentFragment {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/SuggestionSearchContext.java b/server/src/main/java/org/opensearch/search/suggest/SuggestionSearchContext.java
index 881bc1f091883..f0d8efc64b6b3 100644
--- a/server/src/main/java/org/opensearch/search/suggest/SuggestionSearchContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/SuggestionSearchContext.java
@@ -38,6 +38,11 @@
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+/**
+ * Context used for suggestion based search
+ *
+ * @opensearch.internal
+ */
 public class SuggestionSearchContext {
 
     private final Map<String, SuggestionContext> suggestions = new LinkedHashMap<>(4);
@@ -50,6 +55,11 @@ public Map<String, SuggestionContext> suggestions() {
         return suggestions;
     }
 
+    /**
+     * The suggestion context
+     *
+     * @opensearch.internal
+     */
     public abstract static class SuggestionContext {
 
         private BytesRef text;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionStats.java b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionStats.java
index 098e00d5f382f..b54f988218ac8 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionStats.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionStats.java
@@ -33,15 +33,20 @@
 
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats for completion suggester
+ *
+ * @opensearch.internal
+ */
 public class CompletionStats implements Writeable, ToXContentFragment {
 
     private static final String COMPLETION = "completion";
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggester.java b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggester.java
index ba6db16722125..af7b1a798a779 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggester.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggester.java
@@ -40,7 +40,7 @@
 import org.apache.lucene.search.suggest.document.TopSuggestDocs;
 import org.apache.lucene.search.suggest.document.TopSuggestDocsCollector;
 import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggester;
@@ -51,6 +51,11 @@
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * The completion suggester implementation
+ *
+ * @opensearch.internal
+ */
 public class CompletionSuggester extends Suggester<CompletionSuggestionContext> {
 
     public static final CompletionSuggester INSTANCE = new CompletionSuggester();
@@ -98,7 +103,7 @@ protected Suggest.Suggestion<? extends Suggest.Suggestion.Entry<? extends Sugges
     }
 
     private static void suggest(IndexSearcher searcher, CompletionQuery query, TopSuggestDocsCollector collector) throws IOException {
-        query = (CompletionQuery) query.rewrite(searcher.getIndexReader());
+        query = (CompletionQuery) query.rewrite(searcher);
         Weight weight = query.createWeight(searcher, collector.scoreMode(), 1f);
         for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
             BulkScorer scorer = weight.bulkScorer(context);
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestion.java b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestion.java
index 3f6a3138daa1f..96e47cf7c8000 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestion.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestion.java
@@ -34,14 +34,14 @@
 import org.apache.lucene.analysis.CharArraySet;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.util.PriorityQueue;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggest.Suggestion;
@@ -57,7 +57,7 @@
 import java.util.Objects;
 import java.util.Set;
 
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.search.SearchHit.unknownMetaFieldConsumer;
 import static org.opensearch.search.suggest.Suggest.COMPARATOR;
 
@@ -76,6 +76,7 @@
  *     ..
  * }
  *
+ * @opensearch.internal
  */
 public final class CompletionSuggestion extends Suggest.Suggestion<CompletionSuggestion.Entry> {
 
@@ -255,6 +256,11 @@ protected Entry newEntry(StreamInput in) throws IOException {
         return new Entry(in);
     }
 
+    /**
+     * Entry in the completion suggester
+     *
+     * @opensearch.internal
+     */
     public static final class Entry extends Suggest.Suggestion.Entry<CompletionSuggestion.Entry.Option> {
 
         public Entry(Text text, int offset, int length) {
@@ -286,6 +292,11 @@ public static Entry fromXContent(XContentParser parser) {
             return PARSER.apply(parser, null);
         }
 
+        /**
+         * Options for the completion suggester
+         *
+         * @opensearch.internal
+         */
         public static class Option extends Suggest.Suggestion.Entry.Option {
             private final Map<String, Set<String>> contexts;
             private final ScoreDoc doc;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionBuilder.java b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionBuilder.java
index f9b65d49015ac..6724a48c26a63 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionBuilder.java
@@ -32,20 +32,20 @@
 package org.opensearch.search.suggest.completion;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
@@ -67,10 +67,12 @@
  * for users as they type search terms. The implementation of the completion service uses FSTs that
  * are created at index-time and so must be defined in the mapping with the type "completion" before
  * indexing.
+ *
+ * @opensearch.internal
  */
 public class CompletionSuggestionBuilder extends SuggestionBuilder<CompletionSuggestionBuilder> {
 
-    private static final XContentType CONTEXT_BYTES_XCONTENT_TYPE = XContentType.JSON;
+    private static final MediaType CONTEXT_BYTES_XCONTENT_TYPE = MediaTypeRegistry.JSON;
 
     static final ParseField CONTEXTS_FIELD = new ParseField("contexts", "context");
     static final ParseField SKIP_DUPLICATES_FIELD = new ParseField("skip_duplicates");
@@ -109,7 +111,7 @@ public class CompletionSuggestionBuilder extends SuggestionBuilder<CompletionSug
         PARSER.declareInt(CompletionSuggestionBuilder.InnerBuilder::shardSize, SHARDSIZE_FIELD);
         PARSER.declareField((p, v, c) -> {
             // Copy the current structure. We will parse, once the mapping is provided
-            XContentBuilder builder = XContentFactory.contentBuilder(CONTEXT_BYTES_XCONTENT_TYPE);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(CONTEXT_BYTES_XCONTENT_TYPE);
             builder.copyCurrentStructure(p);
             v.contextBytes = BytesReference.bytes(builder);
             p.skipChildren();
@@ -214,7 +216,7 @@ public CompletionSuggestionBuilder regex(String regex, RegexOptions regexOptions
     public CompletionSuggestionBuilder contexts(Map<String, List<? extends ToXContent>> queryContexts) {
         Objects.requireNonNull(queryContexts, "contexts must not be null");
         try {
-            XContentBuilder contentBuilder = XContentFactory.contentBuilder(CONTEXT_BYTES_XCONTENT_TYPE);
+            XContentBuilder contentBuilder = MediaTypeRegistry.contentBuilder(CONTEXT_BYTES_XCONTENT_TYPE);
             contentBuilder.startObject();
             for (Map.Entry<String, List<? extends ToXContent>> contextEntry : queryContexts.entrySet()) {
                 contentBuilder.startArray(contextEntry.getKey());
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionContext.java b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionContext.java
index 1fbea11ab0b4c..f92b7f7ed82ba 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/CompletionSuggestionContext.java
@@ -44,6 +44,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Context used for the completion suggester
+ *
+ * @opensearch.internal
+ */
 public class CompletionSuggestionContext extends SuggestionSearchContext.SuggestionContext {
 
     protected CompletionSuggestionContext(QueryShardContext shardContext) {
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/FuzzyOptions.java b/server/src/main/java/org/opensearch/search/suggest/completion/FuzzyOptions.java
index 97c049af25eea..56cc8fbfbcf66 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/FuzzyOptions.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/FuzzyOptions.java
@@ -34,21 +34,23 @@
 
 import org.apache.lucene.search.suggest.document.FuzzyCompletionQuery;
 import org.apache.lucene.util.automaton.Operations;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Fuzzy options for completion suggester
+ *
+ * @opensearch.internal
  */
 public class FuzzyOptions implements ToXContentFragment, Writeable {
     static final ParseField FUZZY_OPTIONS = new ParseField("fuzzy");
@@ -218,6 +220,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     /**
      * Options for fuzzy queries
+     *
+     * @opensearch.internal
      */
     public static class Builder {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/RegexOptions.java b/server/src/main/java/org/opensearch/search/suggest/completion/RegexOptions.java
index 2cb746bbd589c..fb00d6b186314 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/RegexOptions.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/RegexOptions.java
@@ -35,20 +35,22 @@
 import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.RegexpFlag;
 
 import java.io.IOException;
 
 /**
  * Regular expression options for completion suggester
+ *
+ * @opensearch.internal
  */
 public class RegexOptions implements ToXContentFragment, Writeable {
     static final ParseField REGEX_OPTIONS = new ParseField("regex");
@@ -153,6 +155,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     /**
      * Options for regular expression queries
+     *
+     * @opensearch.internal
      */
     public static class Builder {
         private int flagsValue = RegExp.ALL;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/TopSuggestGroupDocsCollector.java b/server/src/main/java/org/opensearch/search/suggest/completion/TopSuggestGroupDocsCollector.java
index 9405bf82da186..4fbd661037aa9 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/TopSuggestGroupDocsCollector.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/TopSuggestGroupDocsCollector.java
@@ -47,6 +47,8 @@
  * This collector groups suggestions coming from the same document but matching different contexts
  * or surface form together. When different contexts or surface forms match the same suggestion form only
  * the best one per document (sorted by weight) is kept.
+ *
+ * @opensearch.internal
  **/
 class TopSuggestGroupDocsCollector extends TopSuggestDocsCollector {
     private Map<Integer, List<CharSequence>> docContexts = new HashMap<>();
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryContextMapping.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryContextMapping.java
index 8da248ac35bc4..32a73e3702b08 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryContextMapping.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryContextMapping.java
@@ -38,9 +38,9 @@
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.ParseContext;
 import org.opensearch.index.mapper.ParseContext.Document;
@@ -61,6 +61,8 @@
  * category (string) value.
  * {@link CategoryQueryContext} defines options for constructing
  * a unit of query context for this context type
+ *
+ * @opensearch.internal
  */
 public class CategoryContextMapping extends ContextMapping<CategoryQueryContext> {
 
@@ -217,6 +219,8 @@ public int hashCode() {
 
     /**
      * Builder for {@link CategoryContextMapping}
+     *
+     * @opensearch.internal
      */
     public static class Builder extends ContextBuilder<CategoryContextMapping> {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryQueryContext.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryQueryContext.java
index f85d263c01592..bdd9827256d68 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryQueryContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/CategoryQueryContext.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.suggest.completion.context;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -48,6 +48,8 @@
 
 /**
  * Defines the query context for {@link CategoryContextMapping}
+ *
+ * @opensearch.internal
  */
 public final class CategoryQueryContext implements ToXContentObject {
     public static final String NAME = "category";
@@ -149,6 +151,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder for the category query context
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private String category;
         private boolean isPrefix = false;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextBuilder.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextBuilder.java
index f2e4436c1fb0f..9fe2e885fc3fa 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextBuilder.java
@@ -34,6 +34,8 @@
 
 /**
  * Builder for {@link ContextMapping}
+ *
+ * @opensearch.internal
  */
 public abstract class ContextBuilder<E extends ContextMapping<?>> {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMapping.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMapping.java
index 497a7500f4968..61e60293f4943 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMapping.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMapping.java
@@ -34,13 +34,12 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.ParseContext;
@@ -57,6 +56,8 @@
  * filter and/or boost suggestions at query time for {@link CompletionFieldMapper}.
  *
  * Implementations have to define how contexts are parsed at query/index time
+ *
+ * @opensearch.internal
  */
 public abstract class ContextMapping<T extends ToXContent> implements ToXContentFragment {
 
@@ -65,6 +66,11 @@ public abstract class ContextMapping<T extends ToXContent> implements ToXContent
     protected final Type type;
     protected final String name;
 
+    /**
+     * Type of context mapping
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         CATEGORY,
         GEO;
@@ -181,12 +187,17 @@ public int hashCode() {
     @Override
     public String toString() {
         try {
-            return Strings.toString(toXContent(JsonXContent.contentBuilder(), ToXContent.EMPTY_PARAMS));
+            return toXContent(JsonXContent.contentBuilder(), ToXContent.EMPTY_PARAMS).toString();
         } catch (IOException e) {
             return super.toString();
         }
     }
 
+    /**
+     * The internal query context
+     *
+     * @opensearch.internal
+     */
     public static class InternalQueryContext {
         public final String context;
         public final int boost;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMappings.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMappings.java
index 76b5081607715..0f5781fefcf07 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMappings.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/ContextMappings.java
@@ -39,8 +39,8 @@
 import org.apache.lucene.util.CharsRefBuilder;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.DocumentMapperParser;
 import org.opensearch.index.mapper.ParseContext;
@@ -65,6 +65,8 @@
  * ContextMappings indexes context-enabled suggestion fields
  * and creates context queries for defined {@link ContextMapping}s
  * for a {@link CompletionFieldMapper}
+ *
+ * @opensearch.internal
  */
 public class ContextMappings implements ToXContent, Iterable<ContextMapping<?>> {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoContextMapping.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoContextMapping.java
index bb92e6aa0f130..b73061b9e520d 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoContextMapping.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoContextMapping.java
@@ -44,9 +44,9 @@
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.ParseContext;
@@ -75,6 +75,8 @@
  *
  * {@link GeoQueryContext} defines the options for constructing
  * a unit of query context for this context type
+ *
+ * @opensearch.internal
  */
 public class GeoContextMapping extends ContextMapping<GeoQueryContext> {
 
@@ -361,6 +363,11 @@ public int hashCode() {
         return Objects.hash(super.hashCode(), precision, fieldName);
     }
 
+    /**
+     * Builder for geo context mapping
+     *
+     * @opensearch.internal
+     */
     public static class Builder extends ContextBuilder<GeoContextMapping> {
 
         private int precision = DEFAULT_PRECISION;
diff --git a/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoQueryContext.java b/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoQueryContext.java
index e891cbdf72853..82c508e82964b 100644
--- a/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoQueryContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/completion/context/GeoQueryContext.java
@@ -33,13 +33,13 @@
 package org.opensearch.search.suggest.completion.context;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -54,6 +54,8 @@
 
 /**
  * Defines the query context for {@link GeoContextMapping}
+ *
+ * @opensearch.internal
  */
 public final class GeoQueryContext implements ToXContentObject {
     public static final String NAME = "geo";
@@ -175,6 +177,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * Builder for the geo context
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private GeoPoint geoPoint;
         private int boost = 1;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateGenerator.java b/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateGenerator.java
index cea00352374a8..79c21a85681db 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateGenerator.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateGenerator.java
@@ -39,6 +39,12 @@
 import java.io.IOException;
 
 //TODO public for tests
+
+/**
+ * Base class for phrase candidates
+ *
+ * @opensearch.internal
+ */
 public abstract class CandidateGenerator {
 
     public abstract boolean isKnownWord(BytesRef term) throws IOException;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateScorer.java b/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateScorer.java
index aaa50039714c8..3d094cab5802c 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateScorer.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/CandidateScorer.java
@@ -37,6 +37,11 @@
 
 import java.io.IOException;
 
+/**
+ * Scores phrase candidates
+ *
+ * @opensearch.internal
+ */
 final class CandidateScorer {
     private final WordScorer scorer;
     private final int maxNumCorrections;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/Correction.java b/server/src/main/java/org/opensearch/search/suggest/phrase/Correction.java
index 30193da7c4ee8..057d43452ce66 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/Correction.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/Correction.java
@@ -38,6 +38,12 @@
 import java.util.Arrays;
 
 //TODO public for tests
+
+/**
+ * Correction in phrase suggester
+ *
+ * @opensearch.internal
+ */
 public final class Correction implements Comparable<Correction> {
 
     public static final Correction[] EMPTY = new Correction[0];
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGenerator.java b/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGenerator.java
index b49229dc6daf0..8a6cba837d28a 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGenerator.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGenerator.java
@@ -49,7 +49,7 @@
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.CharsRef;
 import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 
 import java.io.CharArrayReader;
 import java.io.IOException;
@@ -65,6 +65,11 @@
 import static java.lang.Math.min;
 import static java.lang.Math.round;
 
+/**
+ * Generates the phrase directly from the IndexReader
+ *
+ * @opensearch.internal
+ */
 public final class DirectCandidateGenerator extends CandidateGenerator {
 
     private final DirectSpellChecker spellchecker;
@@ -273,6 +278,11 @@ int thresholdTermFrequency(int docFreq) {
         return 0;
     }
 
+    /**
+     * Token consumer for a direct candidate
+     *
+     * @opensearch.internal
+     */
     public abstract static class TokenConsumer {
         protected CharTermAttribute charTermAttr;
         protected PositionIncrementAttribute posIncAttr;
@@ -294,6 +304,11 @@ protected BytesRef fillBytesRef(BytesRefBuilder spare) {
         public void end() {}
     }
 
+    /**
+     * Candidate set of terms
+     *
+     * @opensearch.internal
+     */
     public static class CandidateSet {
         public Candidate[] candidates;
         public final Candidate originalTerm;
@@ -323,6 +338,11 @@ public void addOneCandidate(Candidate candidate) {
 
     }
 
+    /**
+     * Candidate term
+     *
+     * @opensearch.internal
+     */
     public static class Candidate implements Comparable<Candidate> {
         public static final Candidate[] EMPTY = new Candidate[0];
         public final BytesRef term;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorBuilder.java b/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorBuilder.java
index 411ec3f8ed791..2e53584384dd5 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorBuilder.java
@@ -41,13 +41,12 @@
 import org.apache.lucene.search.spell.SuggestMode;
 import org.apache.lucene.util.automaton.LevenshteinAutomata;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.search.suggest.SortBy;
 import org.opensearch.search.suggest.phrase.PhraseSuggestionBuilder.CandidateGenerator;
@@ -57,6 +56,11 @@
 import java.util.Objects;
 import java.util.function.Consumer;
 
+/**
+ * Builder for a phrase candidate directly retrieved from an IndexReader
+ *
+ * @opensearch.internal
+ */
 public final class DirectCandidateGeneratorBuilder implements CandidateGenerator {
 
     private static final String TYPE = "direct_generator";
@@ -503,7 +507,7 @@ public String toString() {
             XContentBuilder builder = XContentFactory.jsonBuilder();
             builder.prettyPrint();
             toXContent(builder, EMPTY_PARAMS);
-            return Strings.toString(builder);
+            return builder.toString();
         } catch (Exception e) {
             return "{ \"error\" : \"" + ExceptionsHelper.detailedMessage(e) + "\"}";
         }
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/Laplace.java b/server/src/main/java/org/opensearch/search/suggest/phrase/Laplace.java
index 7c37c1cdf3929..1d2d7861a3587 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/Laplace.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/Laplace.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.search.suggest.phrase.WordScorer.WordScorerFactory;
 
 import java.io.IOException;
@@ -54,6 +54,8 @@
  * href="http://en.wikipedia.org/wiki/N-gram#Smoothing_techniques">N-Gram
  * Smoothing</a> for details.
  * </p>
+ *
+ * @opensearch.internal
  */
 public final class Laplace extends SmoothingModel {
     public static final String NAME = "laplace";
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/LaplaceScorer.java b/server/src/main/java/org/opensearch/search/suggest/phrase/LaplaceScorer.java
index b61e70aee338c..7ac1d14576ea1 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/LaplaceScorer.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/LaplaceScorer.java
@@ -38,6 +38,11 @@
 
 import java.io.IOException;
 
+/**
+ * Scorer implementation based on a laplace computation
+ *
+ * @opensearch.internal
+ */
 final class LaplaceScorer extends WordScorer {
     private double alpha;
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolatingScorer.java b/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolatingScorer.java
index e6982ea586c07..e012dde78c59e 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolatingScorer.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolatingScorer.java
@@ -38,7 +38,12 @@
 
 import java.io.IOException;
 
-//TODO public for tests
+/**
+ * Linear interpolation based scoring
+ *
+ * @opensearch.internal
+ */
+// TODO public for tests
 public final class LinearInterpolatingScorer extends WordScorer {
 
     private final double unigramLambda;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolation.java b/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolation.java
index bb3e022215a31..f1dba9793ba9e 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolation.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/LinearInterpolation.java
@@ -35,13 +35,13 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.search.suggest.phrase.WordScorer.WordScorerFactory;
 
 import java.io.IOException;
@@ -54,6 +54,8 @@
  * href="http://en.wikipedia.org/wiki/N-gram#Smoothing_techniques">N-Gram
  * Smoothing</a> for details.
  * </p>
+ *
+ * @opensearch.internal
  */
 public final class LinearInterpolation extends SmoothingModel {
     public static final String NAME = "linear";
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/MultiCandidateGeneratorWrapper.java b/server/src/main/java/org/opensearch/search/suggest/phrase/MultiCandidateGeneratorWrapper.java
index d6af04eb31442..1fc26ba94264a 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/MultiCandidateGeneratorWrapper.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/MultiCandidateGeneratorWrapper.java
@@ -39,7 +39,12 @@
 import java.io.IOException;
 import java.util.Arrays;
 
-//TODO public for tests
+/**
+ * Wrapper for a multi-candidate generator
+ *
+ * @opensearch.internal
+ */
+// TODO public for tests
 public final class MultiCandidateGeneratorWrapper extends CandidateGenerator {
 
     private final CandidateGenerator[] candidateGenerator;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/NoisyChannelSpellChecker.java b/server/src/main/java/org/opensearch/search/suggest/phrase/NoisyChannelSpellChecker.java
index 67f1897f8e9df..49790c996371a 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/NoisyChannelSpellChecker.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/NoisyChannelSpellChecker.java
@@ -45,6 +45,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Spell checker based on a noisy channel
+ *
+ * @opensearch.internal
+ */
 final class NoisyChannelSpellChecker {
     public static final double REAL_WORD_LIKELIHOOD = 0.95d;
     public static final int DEFAULT_TOKEN_LIMIT = 10;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggester.java b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggester.java
index 71c2326b730cd..dd3e17ae5b42b 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggester.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggester.java
@@ -42,10 +42,10 @@
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.CharsRefBuilder;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.ParsedQuery;
 import org.opensearch.index.query.QueryBuilder;
@@ -64,6 +64,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Phrase suggestion implementation
+ *
+ * @opensearch.internal
+ */
 public final class PhraseSuggester extends Suggester<PhraseSuggestionContext> {
     private final BytesRef SEPARATOR = new BytesRef(" ");
     private static final String SUGGESTION_TEMPLATE_VAR_NAME = "suggestion";
@@ -155,7 +160,8 @@ public Suggestion<? extends Entry<? extends Option>> innerExecute(
                     QueryShardContext shardContext = suggestion.getShardContext();
                     final String querySource = scriptFactory.newInstance(vars).execute();
                     try (
-                        XContentParser parser = XContentFactory.xContent(querySource)
+                        XContentParser parser = MediaTypeRegistry.xContent(querySource)
+                            .xContent()
                             .createParser(shardContext.getXContentRegistry(), LoggingDeprecationHandler.INSTANCE, querySource)
                     ) {
                         QueryBuilder innerQueryBuilder = AbstractQueryBuilder.parseInnerQueryBuilder(parser);
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestion.java b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestion.java
index f5c4de576fdc8..b342f628aa4ac 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestion.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestion.java
@@ -32,24 +32,26 @@
 
 package org.opensearch.search.suggest.phrase;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggest.Suggestion;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Suggestion entry returned from the {@link PhraseSuggester}.
+ *
+ * @opensearch.internal
  */
 public class PhraseSuggestion extends Suggest.Suggestion<PhraseSuggestion.Entry> {
 
@@ -85,6 +87,11 @@ public static PhraseSuggestion fromXContent(XContentParser parser, String name)
         return suggestion;
     }
 
+    /**
+     * Entry in the phrase suggester
+     *
+     * @opensearch.internal
+     */
     public static class Entry extends Suggestion.Entry<PhraseSuggestion.Entry.Option> {
 
         protected double cutoffScore = Double.MIN_VALUE;
@@ -168,6 +175,11 @@ public int hashCode() {
             return Objects.hash(super.hashCode(), cutoffScore);
         }
 
+        /**
+         * Options for phrase suggestion
+         *
+         * @opensearch.internal
+         */
         public static class Option extends Suggestion.Entry.Option {
 
             public Option(Text text, Text highlighted, float score, Boolean collateMatch) {
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionBuilder.java b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionBuilder.java
index 564ec1ee7431e..e37d964cc0424 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionBuilder.java
@@ -33,16 +33,16 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.index.analysis.AnalyzerComponentsProvider;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.analysis.ShingleTokenFilterFactory;
@@ -68,6 +68,8 @@
 
 /**
  * Defines the actual suggest command for phrase suggestions ( {@code phrase}).
+ *
+ * @opensearch.internal
  */
 public class PhraseSuggestionBuilder extends SuggestionBuilder<PhraseSuggestionBuilder> {
 
@@ -770,6 +772,8 @@ protected int doHashCode() {
 
     /**
      * {@link CandidateGenerator} interface.
+     *
+     * @opensearch.internal
      */
     public interface CandidateGenerator extends Writeable, ToXContentObject {
         String getType();
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionContext.java b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionContext.java
index f62a239e388f6..f5107ff9a5d58 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/PhraseSuggestionContext.java
@@ -45,6 +45,11 @@
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Context used during phrase suggestion
+ *
+ * @opensearch.internal
+ */
 class PhraseSuggestionContext extends SuggestionContext {
     static final boolean DEFAULT_COLLATE_PRUNE = false;
     static final boolean DEFAULT_REQUIRE_UNIGRAM = true;
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/SmoothingModel.java b/server/src/main/java/org/opensearch/search/suggest/phrase/SmoothingModel.java
index 916eb451d8fd7..154413d7a6d50 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/SmoothingModel.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/SmoothingModel.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.search.suggest.phrase;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.phrase.WordScorer.WordScorerFactory;
 
 import java.io.IOException;
 
+/**
+ * Smooths the scoring calculation
+ *
+ * @opensearch.internal
+ */
 public abstract class SmoothingModel implements NamedWriteable, ToXContentFragment {
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoff.java b/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoff.java
index 1013b17f62ec2..74a1c447bfe31 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoff.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoff.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.search.suggest.phrase.WordScorer.WordScorerFactory;
 
 import java.io.IOException;
@@ -55,6 +55,8 @@
  * href="http://en.wikipedia.org/wiki/N-gram#Smoothing_techniques">N-Gram
  * Smoothing</a> for details.
  * </p>
+ *
+ * @opensearch.internal
  */
 public final class StupidBackoff extends SmoothingModel {
     /**
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoffScorer.java b/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoffScorer.java
index 96005bdb10650..35de07015b853 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoffScorer.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/StupidBackoffScorer.java
@@ -38,6 +38,11 @@
 
 import java.io.IOException;
 
+/**
+ * naive backoff scorer
+ *
+ * @opensearch.internal
+ */
 class StupidBackoffScorer extends WordScorer {
     private final double discount;
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/phrase/WordScorer.java b/server/src/main/java/org/opensearch/search/suggest/phrase/WordScorer.java
index 8b988ff4ff838..184e3828b06e5 100644
--- a/server/src/main/java/org/opensearch/search/suggest/phrase/WordScorer.java
+++ b/server/src/main/java/org/opensearch/search/suggest/phrase/WordScorer.java
@@ -44,7 +44,12 @@
 
 import java.io.IOException;
 
-//TODO public for tests
+/**
+ * Scores by words
+ *
+ * @opensearch.internal
+ */
+// TODO public for tests
 public abstract class WordScorer {
     protected final IndexReader reader;
     protected final String field;
@@ -128,6 +133,11 @@ public static BytesRef join(BytesRef separator, BytesRefBuilder result, BytesRef
         return result.get();
     }
 
+    /**
+     * Factory for a new scorer
+     *
+     * @opensearch.internal
+     */
     public interface WordScorerFactory {
         WordScorer newScorer(IndexReader reader, Terms terms, String field, double realWordLikelihood, BytesRef separator)
             throws IOException;
diff --git a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggester.java b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggester.java
index 4b480165c9b2d..0c18ae429442b 100644
--- a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggester.java
+++ b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggester.java
@@ -39,8 +39,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.search.suggest.Suggester;
 import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
 import org.opensearch.search.suggest.phrase.DirectCandidateGenerator;
@@ -49,6 +49,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * The Term Suggester implementation
+ *
+ * @opensearch.internal
+ */
 public final class TermSuggester extends Suggester<TermSuggestionContext> {
 
     public static final TermSuggester INSTANCE = new TermSuggester();
diff --git a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestion.java b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestion.java
index 86b1db3ed6ab7..c7bf7f844ccf9 100644
--- a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestion.java
+++ b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestion.java
@@ -33,14 +33,14 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.SortBy;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.Suggest.Suggestion;
@@ -50,10 +50,12 @@
 import java.util.Comparator;
 import java.util.Objects;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
  * The suggestion responses corresponding with the suggestions in the request.
+ *
+ * @opensearch.internal
  */
 public class TermSuggestion extends Suggestion<TermSuggestion.Entry> {
 
@@ -77,8 +79,12 @@ public TermSuggestion(StreamInput in) throws IOException {
         }
     }
 
-    // Same behaviour as comparators in suggest module, but for SuggestedWord
-    // Highest score first, then highest freq first, then lowest term first
+    /**
+     * Same behaviour as comparators in suggest module, but for SuggestedWord
+     * Highest score first, then highest freq first, then lowest term first
+     *
+     * @opensearch.internal
+     */
     public static class Score implements Comparator<Suggestion.Entry.Option> {
 
         @Override
@@ -92,8 +98,12 @@ public int compare(Suggestion.Entry.Option first, Suggestion.Entry.Option second
         }
     }
 
-    // Same behaviour as comparators in suggest module, but for SuggestedWord
-    // Highest freq first, then highest score first, then lowest term first
+    /**
+     * Same behaviour as comparators in suggest module, but for SuggestedWord
+     * Highest freq first, then highest score first, then lowest term first
+     *
+     * @opensearch.internal
+     */
     public static class Frequency implements Comparator<Suggestion.Entry.Option> {
 
         @Override
@@ -179,6 +189,8 @@ public int hashCode() {
 
     /**
      * Represents a part from the suggest text with suggested options.
+     *
+     * @opensearch.internal
      */
     public static class Entry extends Suggest.Suggestion.Entry<TermSuggestion.Entry.Option> {
 
@@ -213,6 +225,8 @@ public static Entry fromXContent(XContentParser parser) {
 
         /**
          * Contains the suggested text with its document frequency and score.
+         *
+         * @opensearch.internal
          */
         public static class Option extends Suggest.Suggestion.Entry.Option {
 
diff --git a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionBuilder.java b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionBuilder.java
index f9cea912a101d..5af9116be2cd0 100644
--- a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionBuilder.java
+++ b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionBuilder.java
@@ -39,12 +39,12 @@
 import org.apache.lucene.search.spell.NGramDistance;
 import org.apache.lucene.search.spell.StringDistance;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.suggest.DirectSpellcheckerSettings;
 import org.opensearch.search.suggest.SortBy;
@@ -77,6 +77,8 @@
  * Defines the actual suggest command. Each command uses the global options
  * unless defined in the suggestion itself. All options are the same as the
  * global options, but are only applicable for this suggestion.
+ *
+ * @opensearch.internal
  */
 public class TermSuggestionBuilder extends SuggestionBuilder<TermSuggestionBuilder> {
 
@@ -510,7 +512,11 @@ protected int doHashCode() {
         );
     }
 
-    /** An enum representing the valid suggest modes. */
+    /**
+     * An enum representing the valid suggest modes.
+     *
+     * @opensearch.internal
+     */
     public enum SuggestMode implements Writeable {
         /** Only suggest terms in the suggest text that aren't in the index. This is the default. */
         MISSING {
@@ -551,7 +557,11 @@ public static SuggestMode resolve(final String str) {
         public abstract org.apache.lucene.search.spell.SuggestMode toLucene();
     }
 
-    /** An enum representing the valid string edit distance algorithms for determining suggestions. */
+    /**
+     * An enum representing the valid string edit distance algorithms for determining suggestions.
+     *
+     * @opensearch.internal
+     */
     public enum StringDistanceImpl implements Writeable {
         /** This is the default and is based on <code>damerau_levenshtein</code>, but highly optimized
          * for comparing string distance for terms inside the index. */
diff --git a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionContext.java b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionContext.java
index 0079d627cdbdc..fce317989f316 100644
--- a/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionContext.java
+++ b/server/src/main/java/org/opensearch/search/suggest/term/TermSuggestionContext.java
@@ -35,6 +35,11 @@
 import org.opensearch.search.suggest.DirectSpellcheckerSettings;
 import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
 
+/**
+ * Context used during term suggestion
+ *
+ * @opensearch.internal
+ */
 final class TermSuggestionContext extends SuggestionContext {
 
     private final DirectSpellcheckerSettings settings = new DirectSpellcheckerSettings();
diff --git a/server/src/main/java/org/opensearch/snapshots/AbortedSnapshotException.java b/server/src/main/java/org/opensearch/snapshots/AbortedSnapshotException.java
index 6aa75ee49bd1e..930d9408552bc 100644
--- a/server/src/main/java/org/opensearch/snapshots/AbortedSnapshotException.java
+++ b/server/src/main/java/org/opensearch/snapshots/AbortedSnapshotException.java
@@ -31,6 +31,11 @@
 
 package org.opensearch.snapshots;
 
+/**
+ * Exception thrown when there is an aborted snapshot
+ *
+ * @opensearch.internal
+ */
 public final class AbortedSnapshotException extends RuntimeException {
     public AbortedSnapshotException() {
         super("aborted");
diff --git a/server/src/main/java/org/opensearch/snapshots/ConcurrentSnapshotExecutionException.java b/server/src/main/java/org/opensearch/snapshots/ConcurrentSnapshotExecutionException.java
index 1bdf09c32ebd2..e0b4d3bf49d2e 100644
--- a/server/src/main/java/org/opensearch/snapshots/ConcurrentSnapshotExecutionException.java
+++ b/server/src/main/java/org/opensearch/snapshots/ConcurrentSnapshotExecutionException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Thrown when a user tries to multiple conflicting snapshot/restore operations at the same time.
+ *
+ * @opensearch.internal
  */
 public class ConcurrentSnapshotExecutionException extends SnapshotException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/EmptySnapshotsInfoService.java b/server/src/main/java/org/opensearch/snapshots/EmptySnapshotsInfoService.java
index c29d39966dc9c..5d75f32cc1c30 100644
--- a/server/src/main/java/org/opensearch/snapshots/EmptySnapshotsInfoService.java
+++ b/server/src/main/java/org/opensearch/snapshots/EmptySnapshotsInfoService.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.collect.ImmutableOpenMap;
+import java.util.Map;
 
+/**
+ * Service for getting information about empty snapshots
+ *
+ * @opensearch.internal
+ */
 public class EmptySnapshotsInfoService implements SnapshotsInfoService {
     public static final EmptySnapshotsInfoService INSTANCE = new EmptySnapshotsInfoService();
 
     @Override
     public SnapshotShardSizeInfo snapshotShardSizes() {
-        return new SnapshotShardSizeInfo(ImmutableOpenMap.of());
+        return new SnapshotShardSizeInfo(Map.of());
     }
 }
diff --git a/server/src/main/java/org/opensearch/snapshots/InFlightShardSnapshotStates.java b/server/src/main/java/org/opensearch/snapshots/InFlightShardSnapshotStates.java
index 469b57562284f..30c4f9483baec 100644
--- a/server/src/main/java/org/opensearch/snapshots/InFlightShardSnapshotStates.java
+++ b/server/src/main/java/org/opensearch/snapshots/InFlightShardSnapshotStates.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.common.Nullable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoryShardId;
 import org.opensearch.repositories.ShardGenerations;
@@ -53,6 +52,8 @@
  * as well as the latest written shard generation per shard in case there is a shard generation for a shard that has
  * been cleanly written out to the repository but not yet made part of the current {@link org.opensearch.repositories.RepositoryData}
  * through a snapshot finalization.
+ *
+ * @opensearch.internal
  */
 public final class InFlightShardSnapshotStates {
 
@@ -71,14 +72,15 @@ public static InFlightShardSnapshotStates forRepo(String repoName, List<Snapshot
                 continue;
             }
             if (runningSnapshot.isClone()) {
-                for (ObjectObjectCursor<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clone : runningSnapshot.clones()) {
-                    final RepositoryShardId repoShardId = clone.key;
-                    addStateInformation(generations, busyIds, clone.value, repoShardId.shardId(), repoShardId.indexName());
+                for (final Map.Entry<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clone : runningSnapshot.clones()
+                    .entrySet()) {
+                    final RepositoryShardId repoShardId = clone.getKey();
+                    addStateInformation(generations, busyIds, clone.getValue(), repoShardId.shardId(), repoShardId.indexName());
                 }
             } else {
-                for (ObjectObjectCursor<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shard : runningSnapshot.shards()) {
-                    final ShardId sid = shard.key;
-                    addStateInformation(generations, busyIds, shard.value, sid.id(), sid.getIndexName());
+                for (final Map.Entry<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shard : runningSnapshot.shards().entrySet()) {
+                    final ShardId sid = shard.getKey();
+                    addStateInformation(generations, busyIds, shard.getValue(), sid.id(), sid.getIndexName());
                 }
             }
         }
diff --git a/server/src/main/java/org/opensearch/snapshots/InternalSnapshotsInfoService.java b/server/src/main/java/org/opensearch/snapshots/InternalSnapshotsInfoService.java
index 5b44b435042e5..3e1f231b513c6 100644
--- a/server/src/main/java/org/opensearch/snapshots/InternalSnapshotsInfoService.java
+++ b/server/src/main/java/org/opensearch/snapshots/InternalSnapshotsInfoService.java
@@ -32,11 +32,9 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateListener;
@@ -47,26 +45,33 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Queue;
 import java.util.Set;
 import java.util.function.Supplier;
 
+/**
+ * Information service for snapshots
+ *
+ * @opensearch.internal
+ */
 public class InternalSnapshotsInfoService implements ClusterStateListener, SnapshotsInfoService {
 
     public static final Setting<Integer> INTERNAL_SNAPSHOT_INFO_MAX_CONCURRENT_FETCHES_SETTING = Setting.intSetting(
@@ -89,7 +94,7 @@ public class InternalSnapshotsInfoService implements ClusterStateListener, Snaps
     private final Supplier<RerouteService> rerouteService;
 
     /** contains the snapshot shards for which the size is known **/
-    private volatile ImmutableOpenMap<SnapshotShard, Long> knownSnapshotShards;
+    private volatile Map<SnapshotShard, Long> knownSnapshotShards;
 
     private volatile boolean isMaster;
 
@@ -116,7 +121,7 @@ public InternalSnapshotsInfoService(
         this.threadPool = clusterService.getClusterApplierService().threadPool();
         this.repositoriesService = repositoriesServiceSupplier;
         this.rerouteService = rerouteServiceSupplier;
-        this.knownSnapshotShards = ImmutableOpenMap.of();
+        this.knownSnapshotShards = Map.of();
         this.unknownSnapshotShards = new LinkedHashSet<>();
         this.failedSnapshotShards = new LinkedHashSet<>();
         this.queue = new LinkedList<>();
@@ -125,7 +130,7 @@ public InternalSnapshotsInfoService(
         this.maxConcurrentFetches = INTERNAL_SNAPSHOT_INFO_MAX_CONCURRENT_FETCHES_SETTING.get(settings);
         final ClusterSettings clusterSettings = clusterService.getClusterSettings();
         clusterSettings.addSettingsUpdateConsumer(INTERNAL_SNAPSHOT_INFO_MAX_CONCURRENT_FETCHES_SETTING, this::setMaxConcurrentFetches);
-        if (DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isClusterManagerNode(settings)) {
             clusterService.addListener(this);
         }
     }
@@ -137,20 +142,20 @@ private void setMaxConcurrentFetches(Integer maxConcurrentFetches) {
     @Override
     public SnapshotShardSizeInfo snapshotShardSizes() {
         synchronized (mutex) {
-            final ImmutableOpenMap.Builder<SnapshotShard, Long> snapshotShardSizes = ImmutableOpenMap.builder(knownSnapshotShards);
+            final Map<SnapshotShard, Long> snapshotShardSizes = new HashMap<>(knownSnapshotShards);
             if (failedSnapshotShards.isEmpty() == false) {
                 for (SnapshotShard snapshotShard : failedSnapshotShards) {
                     Long previous = snapshotShardSizes.put(snapshotShard, ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE);
                     assert previous == null : "snapshot shard size already known for " + snapshotShard;
                 }
             }
-            return new SnapshotShardSizeInfo(snapshotShardSizes.build());
+            return new SnapshotShardSizeInfo(snapshotShardSizes);
         }
     }
 
     @Override
     public void clusterChanged(ClusterChangedEvent event) {
-        if (event.localNodeMaster()) {
+        if (event.localNodeClusterManager()) {
             final Set<SnapshotShard> onGoingSnapshotRecoveries = listOfSnapshotShards(event.state());
 
             int unknownShards = 0;
@@ -175,12 +180,12 @@ public void clusterChanged(ClusterChangedEvent event) {
                 fetchNextSnapshotShard();
             }
 
-        } else if (event.previousState().nodes().isLocalNodeElectedMaster()) {
-            // TODO Maybe just clear out non-ongoing snapshot recoveries is the node is master eligible, so that we don't
-            // have to repopulate the data over and over in an unstable master situation?
+        } else if (event.previousState().nodes().isLocalNodeElectedClusterManager()) {
+            // TODO Maybe just clear out non-ongoing snapshot recoveries is the node is cluster-manager eligible, so that we don't
+            // have to repopulate the data over and over in an unstable cluster-manager situation?
             synchronized (mutex) {
                 // information only needed on current master
-                knownSnapshotShards = ImmutableOpenMap.of();
+                knownSnapshotShards = Map.of();
                 failedSnapshotShards.clear();
                 isMaster = false;
                 SnapshotShard snapshotShard;
@@ -245,12 +250,10 @@ protected void doRun() throws Exception {
                 removed = unknownSnapshotShards.remove(snapshotShard);
                 assert removed : "snapshot shard to remove does not exist " + snapshotShardSize;
                 if (isMaster) {
-                    final ImmutableOpenMap.Builder<SnapshotShard, Long> newSnapshotShardSizes = ImmutableOpenMap.builder(
-                        knownSnapshotShards
-                    );
+                    final Map<SnapshotShard, Long> newSnapshotShardSizes = new HashMap<>(knownSnapshotShards);
                     updated = newSnapshotShardSizes.put(snapshotShard, snapshotShardSize) == null;
                     assert updated : "snapshot shard size already exists for " + snapshotShard;
-                    knownSnapshotShards = newSnapshotShardSizes.build();
+                    knownSnapshotShards = Collections.unmodifiableMap(newSnapshotShardSizes);
                 }
                 activeFetches -= 1;
                 assert invariant();
@@ -288,17 +291,17 @@ public void onAfter() {
 
     private void cleanUpSnapshotShardSizes(Set<SnapshotShard> requiredSnapshotShards) {
         assert Thread.holdsLock(mutex);
-        ImmutableOpenMap.Builder<SnapshotShard, Long> newSnapshotShardSizes = null;
-        for (ObjectCursor<SnapshotShard> shard : knownSnapshotShards.keys()) {
-            if (requiredSnapshotShards.contains(shard.value) == false) {
+        HashMap<SnapshotShard, Long> newSnapshotShardSizes = null;
+        for (final SnapshotShard shard : knownSnapshotShards.keySet()) {
+            if (requiredSnapshotShards.contains(shard) == false) {
                 if (newSnapshotShardSizes == null) {
-                    newSnapshotShardSizes = ImmutableOpenMap.builder(knownSnapshotShards);
+                    newSnapshotShardSizes = new HashMap<>(knownSnapshotShards);
                 }
-                newSnapshotShardSizes.remove(shard.value);
+                newSnapshotShardSizes.remove(shard);
             }
         }
         if (newSnapshotShardSizes != null) {
-            knownSnapshotShards = newSnapshotShardSizes.build();
+            knownSnapshotShards = Collections.unmodifiableMap(newSnapshotShardSizes);
         }
         failedSnapshotShards.retainAll(requiredSnapshotShards);
     }
@@ -307,16 +310,16 @@ private boolean invariant() {
         assert Thread.holdsLock(mutex);
         assert activeFetches >= 0 : "active fetches should be greater than or equal to zero but got: " + activeFetches;
         assert activeFetches <= maxConcurrentFetches : activeFetches + " <= " + maxConcurrentFetches;
-        for (ObjectCursor<SnapshotShard> cursor : knownSnapshotShards.keys()) {
-            assert unknownSnapshotShards.contains(cursor.value) == false : "cannot be known and unknown at same time: " + cursor.value;
-            assert failedSnapshotShards.contains(cursor.value) == false : "cannot be known and failed at same time: " + cursor.value;
+        for (final SnapshotShard cursor : knownSnapshotShards.keySet()) {
+            assert unknownSnapshotShards.contains(cursor) == false : "cannot be known and unknown at same time: " + cursor;
+            assert failedSnapshotShards.contains(cursor) == false : "cannot be known and failed at same time: " + cursor;
         }
         for (SnapshotShard shard : unknownSnapshotShards) {
-            assert knownSnapshotShards.keys().contains(shard) == false : "cannot be unknown and known at same time: " + shard;
+            assert knownSnapshotShards.keySet().contains(shard) == false : "cannot be unknown and known at same time: " + shard;
             assert failedSnapshotShards.contains(shard) == false : "cannot be unknown and failed at same time: " + shard;
         }
         for (SnapshotShard shard : failedSnapshotShards) {
-            assert knownSnapshotShards.keys().contains(shard) == false : "cannot be failed and known at same time: " + shard;
+            assert knownSnapshotShards.keySet().contains(shard) == false : "cannot be failed and known at same time: " + shard;
             assert unknownSnapshotShards.contains(shard) == false : "cannot be failed and unknown at same time: " + shard;
         }
         return true;
@@ -358,6 +361,12 @@ private static Set<SnapshotShard> listOfSnapshotShards(final ClusterState state)
         return Collections.unmodifiableSet(snapshotShards);
     }
 
+    /**
+     * A snapshot of a shard
+     *
+     * @opensearch.internal
+     */
+
     public static class SnapshotShard {
 
         private final Snapshot snapshot;
diff --git a/server/src/main/java/org/opensearch/snapshots/InvalidSnapshotNameException.java b/server/src/main/java/org/opensearch/snapshots/InvalidSnapshotNameException.java
index 8fe321a4fe74b..9dce7127ccf37 100644
--- a/server/src/main/java/org/opensearch/snapshots/InvalidSnapshotNameException.java
+++ b/server/src/main/java/org/opensearch/snapshots/InvalidSnapshotNameException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Thrown on the attempt to create a snapshot with invalid name
+ *
+ * @opensearch.internal
  */
 public class InvalidSnapshotNameException extends SnapshotException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/RestoreInfo.java b/server/src/main/java/org/opensearch/snapshots/RestoreInfo.java
index fbcd54fd5d6d1..5a628eb7f04a0 100644
--- a/server/src/main/java/org/opensearch/snapshots/RestoreInfo.java
+++ b/server/src/main/java/org/opensearch/snapshots/RestoreInfo.java
@@ -31,16 +31,17 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -51,6 +52,8 @@
  * Information about successfully completed restore operation.
  * <p>
  * Returned as part of {@link org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse}
+ *
+ * @opensearch.internal
  */
 public class RestoreInfo implements ToXContentObject, Writeable {
 
@@ -212,6 +215,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 }
diff --git a/server/src/main/java/org/opensearch/snapshots/RestoreService.java b/server/src/main/java/org/opensearch/snapshots/RestoreService.java
index ad5cfe6e443ff..487c1d3f5fd4c 100644
--- a/server/src/main/java/org/opensearch/snapshots/RestoreService.java
+++ b/server/src/main/java/org/opensearch/snapshots/RestoreService.java
@@ -31,20 +31,16 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.IntHashSet;
-import com.carrotsearch.hppc.IntSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterInfo;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.ClusterStateTaskConfig;
@@ -71,21 +67,29 @@
 import org.opensearch.cluster.routing.RoutingChangesObserver;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
+import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
@@ -103,6 +107,7 @@
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.unmodifiableSet;
@@ -112,9 +117,14 @@
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_INDEX_UUID;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_UPGRADED;
+import static org.opensearch.common.util.FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY;
 import static org.opensearch.common.util.set.Sets.newHashSet;
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectory.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION;
+import static org.opensearch.index.store.remote.filecache.FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING;
+import static org.opensearch.node.Node.NODE_SEARCH_CACHE_SIZE_SETTING;
 import static org.opensearch.snapshots.SnapshotUtils.filterIndices;
 
 /**
@@ -122,7 +132,7 @@
  * <p>
  * Restore operation is performed in several stages.
  * <p>
- * First {@link #restoreSnapshot(RestoreSnapshotRequest, org.opensearch.action.ActionListener)}
+ * First {@link #restoreSnapshot(RestoreSnapshotRequest, ActionListener)}
  * method reads information about snapshot and metadata from repository. In update cluster state task it checks restore
  * preconditions, restores global state if needed, creates {@link RestoreInProgress} record with list of shards that needs
  * to be restored and adds this shard to the routing table using
@@ -136,6 +146,8 @@
  * At the end of the successful restore process {@code RestoreService} calls {@link #cleanupRestoreState(ClusterChangedEvent)},
  * which removes {@link RestoreInProgress} when all shards are completed. In case of
  * restore failure a normal recovery fail-over process kicks in.
+ *
+ * @opensearch.internal
  */
 public class RestoreService implements ClusterStateApplier {
 
@@ -171,6 +183,12 @@ public class RestoreService implements ClusterStateApplier {
 
     private final ClusterSettings clusterSettings;
 
+    private final IndicesService indicesService;
+
+    private final Supplier<ClusterInfo> clusterInfoSupplier;
+
+    private final ClusterManagerTaskThrottler.ThrottlingKey restoreSnapshotTaskKey;
+
     private static final CleanRestoreStateTaskExecutor cleanRestoreStateTaskExecutor = new CleanRestoreStateTaskExecutor();
 
     public RestoreService(
@@ -179,19 +197,26 @@ public RestoreService(
         AllocationService allocationService,
         MetadataCreateIndexService createIndexService,
         MetadataIndexUpgradeService metadataIndexUpgradeService,
-        ClusterSettings clusterSettings,
-        ShardLimitValidator shardLimitValidator
+        ShardLimitValidator shardLimitValidator,
+        IndicesService indicesService,
+        Supplier<ClusterInfo> clusterInfoSupplier
     ) {
         this.clusterService = clusterService;
         this.repositoriesService = repositoriesService;
         this.allocationService = allocationService;
         this.createIndexService = createIndexService;
         this.metadataIndexUpgradeService = metadataIndexUpgradeService;
-        if (DiscoveryNode.isMasterNode(clusterService.getSettings())) {
+        if (DiscoveryNode.isClusterManagerNode(clusterService.getSettings())) {
             clusterService.addStateApplier(this);
         }
         this.clusterSettings = clusterService.getClusterSettings();
         this.shardLimitValidator = shardLimitValidator;
+        this.indicesService = indicesService;
+        this.clusterInfoSupplier = clusterInfoSupplier;
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        restoreSnapshotTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.RESTORE_SNAPSHOT_KEY, true);
+
     }
 
     /**
@@ -295,6 +320,11 @@ public void restoreSnapshot(final RestoreSnapshotRequest request, final ActionLi
                     final String restoreUUID = UUIDs.randomBase64UUID();
                     RestoreInfo restoreInfo = null;
 
+                    @Override
+                    public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                        return restoreSnapshotTaskKey;
+                    }
+
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         RestoreInProgress restoreInProgress = currentState.custom(RestoreInProgress.TYPE, RestoreInProgress.EMPTY);
@@ -327,32 +357,67 @@ public ClusterState execute(ClusterState currentState) {
                         Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
                         ClusterBlocks.Builder blocks = ClusterBlocks.builder().blocks(currentState.blocks());
                         RoutingTable.Builder rtBuilder = RoutingTable.builder(currentState.routingTable());
-                        ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards;
+                        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards;
+                        final boolean isRemoteSnapshot = IndexModule.Type.REMOTE_SNAPSHOT.match(request.storageType().toString());
                         Set<String> aliases = new HashSet<>();
+                        long totalRestorableRemoteIndexesSize = 0;
 
                         if (indices.isEmpty() == false) {
                             // We have some indices to restore
-                            ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shardsBuilder = ImmutableOpenMap
-                                .builder();
-                            final Version minIndexCompatibilityVersion = currentState.getNodes()
-                                .getMaxNodeVersion()
-                                .minimumIndexCompatibilityVersion();
+                            Map<ShardId, RestoreInProgress.ShardRestoreStatus> shardsBuilder = new HashMap<>();
+
                             for (Map.Entry<String, String> indexEntry : indices.entrySet()) {
+                                String renamedIndexName = indexEntry.getKey();
                                 String index = indexEntry.getValue();
                                 boolean partial = checkPartial(index);
-                                SnapshotRecoverySource recoverySource = new SnapshotRecoverySource(
+
+                                IndexId snapshotIndexId = repositoryData.resolveIndexId(index);
+                                IndexMetadata snapshotIndexMetadata = updateIndexSettings(
+                                    metadata.index(index),
+                                    request.indexSettings(),
+                                    request.ignoreIndexSettings()
+                                );
+                                if (isRemoteSnapshot) {
+                                    snapshotIndexMetadata = addSnapshotToIndexSettings(snapshotIndexMetadata, snapshot, snapshotIndexId);
+                                }
+                                final boolean isSearchableSnapshot = IndexModule.Type.REMOTE_SNAPSHOT.match(
+                                    snapshotIndexMetadata.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey())
+                                );
+                                final boolean isRemoteStoreShallowCopy = Boolean.TRUE.equals(
+                                    snapshotInfo.isRemoteStoreIndexShallowCopyEnabled()
+                                ) && metadata.index(index).getSettings().getAsBoolean(SETTING_REMOTE_STORE_ENABLED, false);
+                                if (isSearchableSnapshot && isRemoteStoreShallowCopy) {
+                                    throw new SnapshotRestoreException(
+                                        snapshot,
+                                        "Shallow copy snapshot cannot be restored as searchable snapshot."
+                                    );
+                                }
+                                if (isRemoteStoreShallowCopy && !currentState.getNodes().getMinNodeVersion().onOrAfter(Version.V_2_9_0)) {
+                                    throw new SnapshotRestoreException(
+                                        snapshot,
+                                        "cannot restore shallow copy snapshot for index ["
+                                            + index
+                                            + "] as some of the nodes in cluster have version less than 2.9"
+                                    );
+                                }
+                                final SnapshotRecoverySource recoverySource = new SnapshotRecoverySource(
                                     restoreUUID,
                                     snapshot,
                                     snapshotInfo.version(),
-                                    repositoryData.resolveIndexId(index)
-                                );
-                                String renamedIndexName = indexEntry.getKey();
-                                IndexMetadata snapshotIndexMetadata = metadata.index(index);
-                                snapshotIndexMetadata = updateIndexSettings(
-                                    snapshotIndexMetadata,
-                                    request.indexSettings(),
-                                    request.ignoreIndexSettings()
+                                    snapshotIndexId,
+                                    isSearchableSnapshot,
+                                    isRemoteStoreShallowCopy,
+                                    request.getSourceRemoteStoreRepository()
                                 );
+                                final Version minIndexCompatibilityVersion;
+                                if (isSearchableSnapshot && isSearchableSnapshotsExtendedCompatibilityEnabled()) {
+                                    minIndexCompatibilityVersion = SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION
+                                        .minimumIndexCompatibilityVersion();
+                                } else {
+                                    minIndexCompatibilityVersion = currentState.getNodes()
+                                        .getMaxNodeVersion()
+                                        .minimumIndexCompatibilityVersion();
+                                }
                                 try {
                                     snapshotIndexMetadata = metadataIndexUpgradeService.upgradeIndexMetadata(
                                         snapshotIndexMetadata,
@@ -367,7 +432,7 @@ public ClusterState execute(ClusterState currentState) {
                                 }
                                 // Check that the index is closed or doesn't exist
                                 IndexMetadata currentIndexMetadata = currentState.metadata().index(renamedIndexName);
-                                IntSet ignoreShards = new IntHashSet();
+                                Set<Integer> ignoreShards = new HashSet<>();
                                 final Index renamedIndex;
                                 if (currentIndexMetadata == null) {
                                     // Index doesn't exist - create it and start recovery
@@ -384,13 +449,17 @@ public ClusterState execute(ClusterState currentState) {
                                             .put(snapshotIndexMetadata.getSettings())
                                             .put(IndexMetadata.SETTING_INDEX_UUID, UUIDs.randomBase64UUID())
                                     );
-                                    shardLimitValidator.validateShardLimit(snapshotIndexMetadata.getSettings(), currentState);
+                                    shardLimitValidator.validateShardLimit(
+                                        renamedIndexName,
+                                        snapshotIndexMetadata.getSettings(),
+                                        currentState
+                                    );
                                     if (!request.includeAliases() && !snapshotIndexMetadata.getAliases().isEmpty()) {
                                         // Remove all aliases - they shouldn't be restored
                                         indexMdBuilder.removeAllAliases();
                                     } else {
-                                        for (ObjectCursor<String> alias : snapshotIndexMetadata.getAliases().keys()) {
-                                            aliases.add(alias.value);
+                                        for (final String alias : snapshotIndexMetadata.getAliases().keySet()) {
+                                            aliases.add(alias);
                                         }
                                     }
                                     IndexMetadata updatedIndexMetadata = indexMdBuilder.build();
@@ -432,12 +501,12 @@ public ClusterState execute(ClusterState currentState) {
                                             indexMdBuilder.removeAllAliases();
                                         }
                                         /// Add existing aliases
-                                        for (ObjectCursor<AliasMetadata> alias : currentIndexMetadata.getAliases().values()) {
-                                            indexMdBuilder.putAlias(alias.value);
+                                        for (final AliasMetadata alias : currentIndexMetadata.getAliases().values()) {
+                                            indexMdBuilder.putAlias(alias);
                                         }
                                     } else {
-                                        for (ObjectCursor<String> alias : snapshotIndexMetadata.getAliases().keys()) {
-                                            aliases.add(alias.value);
+                                        for (final String alias : snapshotIndexMetadata.getAliases().keySet()) {
+                                            aliases.add(alias);
                                         }
                                     }
                                     final Settings.Builder indexSettingsBuilder = Settings.builder()
@@ -459,6 +528,14 @@ public ClusterState execute(ClusterState currentState) {
                                 }
 
                                 for (int shard = 0; shard < snapshotIndexMetadata.getNumberOfShards(); shard++) {
+                                    if (isRemoteSnapshot) {
+                                        IndexShardSnapshotStatus.Copy shardStatus = repository.getShardSnapshotStatus(
+                                            snapshotInfo.snapshotId(),
+                                            snapshotIndexId,
+                                            new ShardId(metadata.index(index).getIndex(), shard)
+                                        ).asCopy();
+                                        totalRestorableRemoteIndexesSize += shardStatus.getTotalSize();
+                                    }
                                     if (!ignoreShards.contains(shard)) {
                                         shardsBuilder.put(
                                             new ShardId(renamedIndex, shard),
@@ -476,7 +553,7 @@ public ClusterState execute(ClusterState currentState) {
                                 }
                             }
 
-                            shards = shardsBuilder.build();
+                            shards = Collections.unmodifiableMap(shardsBuilder);
                             RestoreInProgress.Entry restoreEntry = new RestoreInProgress.Entry(
                                 restoreUUID,
                                 snapshot,
@@ -491,10 +568,13 @@ public ClusterState execute(ClusterState currentState) {
                                 ).build()
                             );
                         } else {
-                            shards = ImmutableOpenMap.of();
+                            shards = Map.of();
                         }
 
                         checkAliasNameConflicts(indices, aliases);
+                        if (isRemoteSnapshot) {
+                            validateSearchableSnapshotRestorable(totalRestorableRemoteIndexesSize);
+                        }
 
                         Map<String, DataStream> updatedDataStreams = new HashMap<>(currentState.metadata().dataStreams());
                         updatedDataStreams.putAll(
@@ -514,18 +594,18 @@ public ClusterState execute(ClusterState currentState) {
                             }
                             if (metadata.templates() != null) {
                                 // TODO: Should all existing templates be deleted first?
-                                for (ObjectCursor<IndexTemplateMetadata> cursor : metadata.templates().values()) {
-                                    mdBuilder.put(cursor.value);
+                                for (final IndexTemplateMetadata cursor : metadata.templates().values()) {
+                                    mdBuilder.put(cursor);
                                 }
                             }
                             if (metadata.customs() != null) {
-                                for (ObjectObjectCursor<String, Metadata.Custom> cursor : metadata.customs()) {
-                                    if (RepositoriesMetadata.TYPE.equals(cursor.key) == false
-                                        && DataStreamMetadata.TYPE.equals(cursor.key) == false) {
+                                for (final Map.Entry<String, Metadata.Custom> cursor : metadata.customs().entrySet()) {
+                                    if (RepositoriesMetadata.TYPE.equals(cursor.getKey()) == false
+                                        && DataStreamMetadata.TYPE.equals(cursor.getKey()) == false) {
                                         // Don't restore repositories while we are working with them
                                         // TODO: Should we restore them at the end?
                                         // Also, don't restore data streams here, we already added them to the metadata builder above
-                                        mdBuilder.putCustom(cursor.key, cursor.value);
+                                        mdBuilder.putCustom(cursor.getKey(), cursor.getValue());
                                     }
                                 }
                             }
@@ -561,7 +641,7 @@ private void checkAliasNameConflicts(Map<String, String> renamedIndices, Set<Str
                         }
                     }
 
-                    private void populateIgnoredShards(String index, IntSet ignoreShards) {
+                    private void populateIgnoredShards(String index, final Set<Integer> ignoreShards) {
                         for (SnapshotShardFailure failure : snapshotInfo.shardFailures()) {
                             if (index.equals(failure.index())) {
                                 ignoreShards.add(failure.shardId());
@@ -694,6 +774,45 @@ private IndexMetadata updateIndexSettings(
                         return builder.settings(settingsBuilder).build();
                     }
 
+                    private void validateSearchableSnapshotRestorable(long totalRestorableRemoteIndexesSize) {
+                        ClusterInfo clusterInfo = clusterInfoSupplier.get();
+                        double remoteDataToFileCacheRatio = DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING.get(clusterService.getSettings());
+                        Map<String, FileCacheStats> nodeFileCacheStats = clusterInfo.getNodeFileCacheStats();
+                        if (nodeFileCacheStats.isEmpty() || remoteDataToFileCacheRatio <= 0.01f) {
+                            return;
+                        }
+
+                        long totalNodeFileCacheSize = clusterInfo.getNodeFileCacheStats()
+                            .values()
+                            .stream()
+                            .map(fileCacheStats -> fileCacheStats.getTotal().getBytes())
+                            .mapToLong(Long::longValue)
+                            .sum();
+
+                        Predicate<ShardRouting> isRemoteSnapshotShard = shardRouting -> shardRouting.primary()
+                            && indicesService.indexService(shardRouting.index()).getIndexSettings().isRemoteSnapshot();
+
+                        ShardsIterator shardsIterator = clusterService.state()
+                            .routingTable()
+                            .allShardsSatisfyingPredicate(isRemoteSnapshotShard);
+
+                        long totalRestoredRemoteIndexesSize = shardsIterator.getShardRoutings()
+                            .stream()
+                            .map(clusterInfo::getShardSize)
+                            .mapToLong(Long::longValue)
+                            .sum();
+
+                        if (totalRestoredRemoteIndexesSize + totalRestorableRemoteIndexesSize > remoteDataToFileCacheRatio
+                            * totalNodeFileCacheSize) {
+                            throw new SnapshotRestoreException(
+                                snapshot,
+                                "Size of the indexes to be restored exceeds the file cache bounds. Increase the file cache capacity on the cluster nodes using "
+                                    + NODE_SEARCH_CACHE_SIZE_SETTING.getKey()
+                                    + " setting."
+                            );
+                        }
+                    }
+
                     @Override
                     public void onFailure(String source, Exception e) {
                         logger.warn(() -> new ParameterizedMessage("[{}] failed to restore snapshot", snapshotId), e);
@@ -702,7 +821,7 @@ public void onFailure(String source, Exception e) {
 
                     @Override
                     public TimeValue timeout() {
-                        return request.masterNodeTimeout();
+                        return request.clusterManagerNodeTimeout();
                     }
 
                     @Override
@@ -737,19 +856,19 @@ public static RestoreInProgress updateRestoreStateWithDeletedIndices(RestoreInPr
         boolean changesMade = false;
         RestoreInProgress.Builder builder = new RestoreInProgress.Builder();
         for (RestoreInProgress.Entry entry : oldRestore) {
-            ImmutableOpenMap.Builder<ShardId, ShardRestoreStatus> shardsBuilder = null;
-            for (ObjectObjectCursor<ShardId, ShardRestoreStatus> cursor : entry.shards()) {
-                ShardId shardId = cursor.key;
+            Map<ShardId, ShardRestoreStatus> shardsBuilder = null;
+            for (final Map.Entry<ShardId, ShardRestoreStatus> cursor : entry.shards().entrySet()) {
+                ShardId shardId = cursor.getKey();
                 if (deletedIndices.contains(shardId.getIndex())) {
                     changesMade = true;
                     if (shardsBuilder == null) {
-                        shardsBuilder = ImmutableOpenMap.builder(entry.shards());
+                        shardsBuilder = new HashMap<>(entry.shards());
                     }
                     shardsBuilder.put(shardId, new ShardRestoreStatus(null, RestoreInProgress.State.FAILURE, "index was deleted"));
                 }
             }
             if (shardsBuilder != null) {
-                ImmutableOpenMap<ShardId, ShardRestoreStatus> shards = shardsBuilder.build();
+                final Map<ShardId, ShardRestoreStatus> shards = Collections.unmodifiableMap(shardsBuilder);
                 builder.add(
                     new RestoreInProgress.Entry(
                         entry.uuid(),
@@ -770,12 +889,17 @@ public static RestoreInProgress updateRestoreStateWithDeletedIndices(RestoreInPr
         }
     }
 
+    /**
+     * Response once restore is completed.
+     *
+     * @opensearch.internal
+     */
     public static final class RestoreCompletionResponse {
         private final String uuid;
         private final Snapshot snapshot;
         private final RestoreInfo restoreInfo;
 
-        private RestoreCompletionResponse(final String uuid, final Snapshot snapshot, final RestoreInfo restoreInfo) {
+        public RestoreCompletionResponse(final String uuid, final Snapshot snapshot, final RestoreInfo restoreInfo) {
             this.uuid = uuid;
             this.snapshot = snapshot;
             this.restoreInfo = restoreInfo;
@@ -794,6 +918,11 @@ public RestoreInfo getRestoreInfo() {
         }
     }
 
+    /**
+     * Updates based on restore progress
+     *
+     * @opensearch.internal
+     */
     public static class RestoreInProgressUpdater extends RoutingChangesObserver.AbstractRoutingChangesObserver {
         // Map of RestoreUUID to a of changes to the shards' restore statuses
         private final Map<String, Map<ShardId, ShardRestoreStatus>> shardChanges = new HashMap<>();
@@ -878,9 +1007,9 @@ public RestoreInProgress applyChanges(final RestoreInProgress oldRestore) {
                 RestoreInProgress.Builder builder = new RestoreInProgress.Builder();
                 for (RestoreInProgress.Entry entry : oldRestore) {
                     Map<ShardId, ShardRestoreStatus> updates = shardChanges.get(entry.uuid());
-                    ImmutableOpenMap<ShardId, ShardRestoreStatus> shardStates = entry.shards();
+                    final Map<ShardId, ShardRestoreStatus> shardStates = entry.shards();
                     if (updates != null && updates.isEmpty() == false) {
-                        ImmutableOpenMap.Builder<ShardId, ShardRestoreStatus> shardsBuilder = ImmutableOpenMap.builder(shardStates);
+                        Map<ShardId, ShardRestoreStatus> shardsBuilder = new HashMap<>(shardStates);
                         for (Map.Entry<ShardId, ShardRestoreStatus> shard : updates.entrySet()) {
                             ShardId shardId = shard.getKey();
                             ShardRestoreStatus status = shardStates.get(shardId);
@@ -889,7 +1018,7 @@ public RestoreInProgress applyChanges(final RestoreInProgress oldRestore) {
                             }
                         }
 
-                        ImmutableOpenMap<ShardId, ShardRestoreStatus> shards = shardsBuilder.build();
+                        final Map<ShardId, ShardRestoreStatus> shards = Collections.unmodifiableMap(shardsBuilder);
                         RestoreInProgress.State newState = overallState(RestoreInProgress.State.STARTED, shards);
                         builder.add(new RestoreInProgress.Entry(entry.uuid(), entry.snapshot(), newState, entry.indices(), shards));
                     } else {
@@ -941,9 +1070,9 @@ public ClusterTasksResult<Task> execute(final ClusterState currentState, final L
             if (changed == false) {
                 return resultBuilder.build(currentState);
             }
-            ImmutableOpenMap.Builder<String, ClusterState.Custom> builder = ImmutableOpenMap.builder(currentState.getCustoms());
+            final Map<String, ClusterState.Custom> builder = new HashMap<>(currentState.getCustoms());
             builder.put(RestoreInProgress.TYPE, restoreInProgressBuilder.build());
-            ImmutableOpenMap<String, ClusterState.Custom> customs = builder.build();
+            final Map<String, ClusterState.Custom> customs = Collections.unmodifiableMap(builder);
             return resultBuilder.build(ClusterState.builder(currentState).customs(customs).build());
         }
 
@@ -953,8 +1082,8 @@ public void onFailure(final String source, final Exception e) {
         }
 
         @Override
-        public void onNoLongerMaster(String source) {
-            logger.debug("no longer master while processing restore state update [{}]", source);
+        public void onNoLongerClusterManager(String source) {
+            logger.debug("no longer cluster-manager while processing restore state update [{}]", source);
         }
 
     }
@@ -976,14 +1105,14 @@ private void cleanupRestoreState(ClusterChangedEvent event) {
 
     private static RestoreInProgress.State overallState(
         RestoreInProgress.State nonCompletedState,
-        ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards
+        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards
     ) {
         boolean hasFailed = false;
-        for (ObjectCursor<RestoreInProgress.ShardRestoreStatus> status : shards.values()) {
-            if (!status.value.state().completed()) {
+        for (RestoreInProgress.ShardRestoreStatus status : shards.values()) {
+            if (status.state().completed() == false) {
                 return nonCompletedState;
             }
-            if (status.value.state() == RestoreInProgress.State.FAILURE) {
+            if (status.state() == RestoreInProgress.State.FAILURE) {
                 hasFailed = true;
             }
         }
@@ -994,19 +1123,19 @@ private static RestoreInProgress.State overallState(
         }
     }
 
-    public static boolean completed(ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards) {
-        for (ObjectCursor<RestoreInProgress.ShardRestoreStatus> status : shards.values()) {
-            if (!status.value.state().completed()) {
+    public static boolean completed(final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards) {
+        for (final RestoreInProgress.ShardRestoreStatus status : shards.values()) {
+            if (status.state().completed() == false) {
                 return false;
             }
         }
         return true;
     }
 
-    public static int failedShards(ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards) {
+    public static int failedShards(final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards) {
         int failedShards = 0;
-        for (ObjectCursor<RestoreInProgress.ShardRestoreStatus> status : shards.values()) {
-            if (status.value.state() == RestoreInProgress.State.FAILURE) {
+        for (final RestoreInProgress.ShardRestoreStatus status : shards.values()) {
+            if (status.state() == RestoreInProgress.State.FAILURE) {
                 failedShards++;
             }
         }
@@ -1088,10 +1217,10 @@ public static boolean failed(SnapshotInfo snapshot, String index) {
     public static Set<Index> restoringIndices(final ClusterState currentState, final Set<Index> indicesToCheck) {
         final Set<Index> indices = new HashSet<>();
         for (RestoreInProgress.Entry entry : currentState.custom(RestoreInProgress.TYPE, RestoreInProgress.EMPTY)) {
-            for (ObjectObjectCursor<ShardId, RestoreInProgress.ShardRestoreStatus> shard : entry.shards()) {
-                Index index = shard.key.getIndex();
+            for (final Map.Entry<ShardId, RestoreInProgress.ShardRestoreStatus> shard : entry.shards().entrySet()) {
+                Index index = shard.getKey().getIndex();
                 if (indicesToCheck.contains(index)
-                    && shard.value.state().completed() == false
+                    && shard.getValue().state().completed() == false
                     && currentState.getMetadata().index(index) != null) {
                     indices.add(index);
                 }
@@ -1103,11 +1232,28 @@ public static Set<Index> restoringIndices(final ClusterState currentState, final
     @Override
     public void applyClusterState(ClusterChangedEvent event) {
         try {
-            if (event.localNodeMaster()) {
+            if (event.localNodeClusterManager()) {
                 cleanupRestoreState(event);
             }
         } catch (Exception t) {
             logger.warn("Failed to update restore state ", t);
         }
     }
+
+    private static IndexMetadata addSnapshotToIndexSettings(IndexMetadata metadata, Snapshot snapshot, IndexId indexId) {
+        final Settings newSettings = Settings.builder()
+            .put(metadata.getSettings())
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_REPOSITORY.getKey(), snapshot.getRepository())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_ID_UUID.getKey(), snapshot.getSnapshotId().getUUID())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_ID_NAME.getKey(), snapshot.getSnapshotId().getName())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_INDEX_ID.getKey(), indexId.getId())
+            .build();
+        return IndexMetadata.builder(metadata).settings(newSettings).build();
+    }
+
+    private static boolean isSearchableSnapshotsExtendedCompatibilityEnabled() {
+        return org.opensearch.Version.CURRENT.after(org.opensearch.Version.V_2_4_0)
+            && FeatureFlags.isEnabled(SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY);
+    }
 }
diff --git a/server/src/main/java/org/opensearch/snapshots/Snapshot.java b/server/src/main/java/org/opensearch/snapshots/Snapshot.java
index 0733ccd6be6f1..e7c92195eff08 100644
--- a/server/src/main/java/org/opensearch/snapshots/Snapshot.java
+++ b/server/src/main/java/org/opensearch/snapshots/Snapshot.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Basic information about a snapshot - a SnapshotId and the repository that the snapshot belongs to.
+ *
+ * @opensearch.internal
  */
 public final class Snapshot implements Writeable {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotCreationException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotCreationException.java
index 6857b38aaecba..a7f16637f6778 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotCreationException.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotCreationException.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown when snapshot creation fails completely
+ *
+ * @opensearch.internal
  */
 public class SnapshotCreationException extends SnapshotException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotException.java
index 641addad169bb..09d213aa2b051 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotException.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotException.java
@@ -34,13 +34,15 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * Generic snapshot exception
+ *
+ * @opensearch.internal
  */
 public class SnapshotException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotId.java b/server/src/main/java/org/opensearch/snapshots/SnapshotId.java
index cbad6ddbb92a6..aec3aebd93585 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotId.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotId.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * SnapshotId - snapshot name + snapshot UUID
+ *
+ * @opensearch.internal
  */
 public final class SnapshotId implements Comparable<SnapshotId>, Writeable, ToXContentObject {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotInProgressException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotInProgressException.java
index 4dc1c49ab3fcc..ae330a1500388 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotInProgressException.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotInProgressException.java
@@ -33,14 +33,16 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Thrown on the attempt to execute an action that requires
  * that no snapshot is in progress.
+ *
+ * @opensearch.internal
  */
 public class SnapshotInProgressException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotInUseDeletionException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotInUseDeletionException.java
new file mode 100644
index 0000000000000..11080c1c39167
--- /dev/null
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotInUseDeletionException.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.snapshots;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+
+import java.io.IOException;
+
+/**
+ * Thrown if requested snapshot/s can't be deleted
+ *
+ * @opensearch.internal
+ */
+public class SnapshotInUseDeletionException extends SnapshotException {
+
+    public SnapshotInUseDeletionException(final String repositoryName, final String snapshotName, final String msg) {
+        super(repositoryName, snapshotName, msg);
+    }
+
+    public SnapshotInUseDeletionException(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.CONFLICT;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotInfo.java b/server/src/main/java/org/opensearch/snapshots/SnapshotInfo.java
index a7c96b88469b7..cd15534ce662b 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotInfo.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotInfo.java
@@ -33,23 +33,23 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.repositories.IndexId;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -64,6 +64,8 @@
 
 /**
  * Information about a snapshot
+ *
+ * @opensearch.internal
  */
 public final class SnapshotInfo implements Comparable<SnapshotInfo>, ToXContent, Writeable {
 
@@ -96,11 +98,18 @@ public final class SnapshotInfo implements Comparable<SnapshotInfo>, ToXContent,
     private static final String TOTAL_SHARDS = "total_shards";
     private static final String SUCCESSFUL_SHARDS = "successful_shards";
     private static final String INCLUDE_GLOBAL_STATE = "include_global_state";
+
+    private static final String REMOTE_STORE_INDEX_SHALLOW_COPY = "remote_store_index_shallow_copy";
     private static final String USER_METADATA = "metadata";
 
     private static final Comparator<SnapshotInfo> COMPARATOR = Comparator.comparing(SnapshotInfo::startTime)
         .thenComparing(SnapshotInfo::snapshotId);
 
+    /**
+     * Builds snapshot information
+     *
+     * @opensearch.internal
+     */
     public static final class SnapshotInfoBuilder {
         private String snapshotName = null;
         private String snapshotUUID = null;
@@ -112,6 +121,8 @@ public static final class SnapshotInfoBuilder {
         private long endTime = 0L;
         private ShardStatsBuilder shardStatsBuilder = null;
         private Boolean includeGlobalState = null;
+
+        private Boolean remoteStoreIndexShallowCopy = null;
         private Map<String, Object> userMetadata = null;
         private int version = -1;
         private List<SnapshotShardFailure> shardFailures = null;
@@ -164,6 +175,10 @@ private void setVersion(int version) {
             this.version = version;
         }
 
+        private void setRemoteStoreIndexShallowCopy(Boolean remoteStoreIndexShallowCopy) {
+            this.remoteStoreIndexShallowCopy = remoteStoreIndexShallowCopy;
+        }
+
         private void setShardFailures(List<SnapshotShardFailure> shardFailures) {
             this.shardFailures = shardFailures;
         }
@@ -202,7 +217,8 @@ public SnapshotInfo build() {
                 successfulShards,
                 shardFailures,
                 includeGlobalState,
-                userMetadata
+                userMetadata,
+                remoteStoreIndexShallowCopy
             );
         }
     }
@@ -253,6 +269,10 @@ int getSuccessfulShards() {
         SNAPSHOT_INFO_PARSER.declareBoolean(SnapshotInfoBuilder::setIncludeGlobalState, new ParseField(INCLUDE_GLOBAL_STATE));
         SNAPSHOT_INFO_PARSER.declareObject(SnapshotInfoBuilder::setUserMetadata, (p, c) -> p.map(), new ParseField(USER_METADATA));
         SNAPSHOT_INFO_PARSER.declareInt(SnapshotInfoBuilder::setVersion, new ParseField(VERSION_ID));
+        SNAPSHOT_INFO_PARSER.declareBoolean(
+            SnapshotInfoBuilder::setRemoteStoreIndexShallowCopy,
+            new ParseField(REMOTE_STORE_INDEX_SHALLOW_COPY)
+        );
         SNAPSHOT_INFO_PARSER.declareObjectArray(
             SnapshotInfoBuilder::setShardFailures,
             SnapshotShardFailure.SNAPSHOT_SHARD_FAILURE_PARSER,
@@ -286,6 +306,9 @@ int getSuccessfulShards() {
     @Nullable
     private Boolean includeGlobalState;
 
+    @Nullable
+    private Boolean remoteStoreIndexShallowCopy;
+
     @Nullable
     private final Map<String, Object> userMetadata;
 
@@ -295,11 +318,11 @@ int getSuccessfulShards() {
     private final List<SnapshotShardFailure> shardFailures;
 
     public SnapshotInfo(SnapshotId snapshotId, List<String> indices, List<String> dataStreams, SnapshotState state) {
-        this(snapshotId, indices, dataStreams, state, null, null, 0L, 0L, 0, 0, Collections.emptyList(), null, null);
+        this(snapshotId, indices, dataStreams, state, null, null, 0L, 0L, 0, 0, Collections.emptyList(), null, null, null);
     }
 
     public SnapshotInfo(SnapshotId snapshotId, List<String> indices, List<String> dataStreams, SnapshotState state, Version version) {
-        this(snapshotId, indices, dataStreams, state, null, version, 0L, 0L, 0, 0, Collections.emptyList(), null, null);
+        this(snapshotId, indices, dataStreams, state, null, version, 0L, 0L, 0, 0, Collections.emptyList(), null, null, null);
     }
 
     public SnapshotInfo(SnapshotsInProgress.Entry entry) {
@@ -316,7 +339,8 @@ public SnapshotInfo(SnapshotsInProgress.Entry entry) {
             0,
             Collections.emptyList(),
             entry.includeGlobalState(),
-            entry.userMetadata()
+            entry.userMetadata(),
+            entry.remoteStoreIndexShallowCopy()
         );
     }
 
@@ -330,7 +354,8 @@ public SnapshotInfo(
         int totalShards,
         List<SnapshotShardFailure> shardFailures,
         Boolean includeGlobalState,
-        Map<String, Object> userMetadata
+        Map<String, Object> userMetadata,
+        Boolean remoteStoreIndexShallowCopy
     ) {
         this(
             snapshotId,
@@ -345,7 +370,8 @@ public SnapshotInfo(
             totalShards - shardFailures.size(),
             shardFailures,
             includeGlobalState,
-            userMetadata
+            userMetadata,
+            remoteStoreIndexShallowCopy
         );
     }
 
@@ -362,7 +388,8 @@ public SnapshotInfo(
         int successfulShards,
         List<SnapshotShardFailure> shardFailures,
         Boolean includeGlobalState,
-        Map<String, Object> userMetadata
+        Map<String, Object> userMetadata,
+        Boolean remoteStoreIndexShallowCopy
     ) {
         this.snapshotId = Objects.requireNonNull(snapshotId);
         this.indices = Collections.unmodifiableList(Objects.requireNonNull(indices));
@@ -377,6 +404,7 @@ public SnapshotInfo(
         this.shardFailures = Objects.requireNonNull(shardFailures);
         this.includeGlobalState = includeGlobalState;
         this.userMetadata = userMetadata;
+        this.remoteStoreIndexShallowCopy = remoteStoreIndexShallowCopy;
     }
 
     /**
@@ -392,7 +420,7 @@ public SnapshotInfo(final StreamInput in) throws IOException {
         totalShards = in.readVInt();
         successfulShards = in.readVInt();
         shardFailures = Collections.unmodifiableList(in.readList(SnapshotShardFailure::new));
-        version = in.readBoolean() ? Version.readVersion(in) : null;
+        version = in.readBoolean() ? in.readVersion() : null;
         includeGlobalState = in.readOptionalBoolean();
         if (in.getVersion().onOrAfter(METADATA_FIELD_INTRODUCED)) {
             userMetadata = in.readMap();
@@ -404,6 +432,9 @@ public SnapshotInfo(final StreamInput in) throws IOException {
         } else {
             dataStreams = Collections.emptyList();
         }
+        if (in.getVersion().onOrAfter(Version.V_2_9_0)) {
+            remoteStoreIndexShallowCopy = in.readOptionalBoolean();
+        }
     }
 
     /**
@@ -513,6 +544,11 @@ public Boolean includeGlobalState() {
         return includeGlobalState;
     }
 
+    @Nullable
+    public Boolean isRemoteStoreIndexShallowCopyEnabled() {
+        return remoteStoreIndexShallowCopy;
+    }
+
     /**
      * Returns shard failures; an empty list will be returned if there were no shard
      * failures, or if {@link #state()} returns {@code null}.
@@ -578,6 +614,8 @@ public String toString() {
             + version
             + ", shardFailures="
             + shardFailures
+            + ", isRemoteStoreInteropEnabled="
+            + remoteStoreIndexShallowCopy
             + '}';
     }
 
@@ -614,6 +652,9 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
             builder.field(VERSION_ID, version.id);
             builder.field(VERSION, version.toString());
         }
+        if (remoteStoreIndexShallowCopy != null) {
+            builder.field(REMOTE_STORE_INDEX_SHALLOW_COPY, remoteStoreIndexShallowCopy);
+        }
         builder.startArray(INDICES);
         for (String index : indices) {
             builder.value(index);
@@ -669,6 +710,9 @@ private XContentBuilder toXContentInternal(final XContentBuilder builder, final
         builder.field(UUID, snapshotId.getUUID());
         assert version != null : "version must always be known when writing a snapshot metadata blob";
         builder.field(VERSION_ID, version.id);
+        if (remoteStoreIndexShallowCopy != null) {
+            builder.field(REMOTE_STORE_INDEX_SHALLOW_COPY, remoteStoreIndexShallowCopy);
+        }
         builder.startArray(INDICES);
         for (String index : indices) {
             builder.value(index);
@@ -718,6 +762,7 @@ public static SnapshotInfo fromXContentInternal(final XContentParser parser) thr
         int totalShards = 0;
         int successfulShards = 0;
         Boolean includeGlobalState = null;
+        Boolean remoteStoreIndexShallowCopy = null;
         Map<String, Object> userMetadata = null;
         List<SnapshotShardFailure> shardFailures = Collections.emptyList();
         if (parser.currentToken() == null) { // fresh parser? move to the first token
@@ -755,6 +800,8 @@ public static SnapshotInfo fromXContentInternal(final XContentParser parser) thr
                             version = Version.fromId(parser.intValue());
                         } else if (INCLUDE_GLOBAL_STATE.equals(currentFieldName)) {
                             includeGlobalState = parser.booleanValue();
+                        } else if (REMOTE_STORE_INDEX_SHALLOW_COPY.equals(currentFieldName)) {
+                            remoteStoreIndexShallowCopy = parser.booleanValue();
                         }
                     } else if (token == XContentParser.Token.START_ARRAY) {
                         if (DATA_STREAMS.equals(currentFieldName)) {
@@ -806,7 +853,8 @@ public static SnapshotInfo fromXContentInternal(final XContentParser parser) thr
             successfulShards,
             shardFailures,
             includeGlobalState,
-            userMetadata
+            userMetadata,
+            remoteStoreIndexShallowCopy
         );
     }
 
@@ -828,7 +876,7 @@ public void writeTo(final StreamOutput out) throws IOException {
         out.writeList(shardFailures);
         if (version != null) {
             out.writeBoolean(true);
-            Version.writeVersion(version, out);
+            out.writeVersion(version);
         } else {
             out.writeBoolean(false);
         }
@@ -839,6 +887,9 @@ public void writeTo(final StreamOutput out) throws IOException {
                 out.writeStringCollection(dataStreams);
             }
         }
+        if (out.getVersion().onOrAfter(Version.V_2_9_0)) {
+            out.writeOptionalBoolean(remoteStoreIndexShallowCopy);
+        }
     }
 
     private static SnapshotState snapshotState(final String reason, final List<SnapshotShardFailure> shardFailures) {
@@ -870,7 +921,8 @@ public boolean equals(Object o) {
             && Objects.equals(includeGlobalState, that.includeGlobalState)
             && Objects.equals(version, that.version)
             && Objects.equals(shardFailures, that.shardFailures)
-            && Objects.equals(userMetadata, that.userMetadata);
+            && Objects.equals(userMetadata, that.userMetadata)
+            && Objects.equals(remoteStoreIndexShallowCopy, that.remoteStoreIndexShallowCopy);
     }
 
     @Override
@@ -889,7 +941,8 @@ public int hashCode() {
             includeGlobalState,
             version,
             shardFailures,
-            userMetadata
+            userMetadata,
+            remoteStoreIndexShallowCopy
         );
     }
 }
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotMissingException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotMissingException.java
index ac8b733526b7c..ca8f89897f333 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotMissingException.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotMissingException.java
@@ -32,13 +32,15 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
 /**
  * Thrown if requested snapshot doesn't exist
+ *
+ * @opensearch.internal
  */
 public class SnapshotMissingException extends SnapshotException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotRestoreException.java b/server/src/main/java/org/opensearch/snapshots/SnapshotRestoreException.java
index ff4d5fa53a857..c1239ecd7df51 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotRestoreException.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotRestoreException.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Snapshot restore exception
+ *
+ * @opensearch.internal
  */
 public class SnapshotRestoreException extends SnapshotException {
     public SnapshotRestoreException(final String repositoryName, final String snapshotName, final String message) {
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotShardFailure.java b/server/src/main/java/org/opensearch/snapshots/SnapshotShardFailure.java
index e0318641003f8..9d47a4edbfa22 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotShardFailure.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotShardFailure.java
@@ -33,24 +33,26 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.snapshots.IndexShardSnapshotFailedException;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Stores information about failures that occurred during shard snapshotting process
+ *
+ * @opensearch.internal
  */
 public class SnapshotShardFailure extends ShardOperationFailedException {
 
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotShardSizeInfo.java b/server/src/main/java/org/opensearch/snapshots/SnapshotShardSizeInfo.java
index 9c8a8fb76fb23..b5818c5650b3c 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotShardSizeInfo.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotShardSizeInfo.java
@@ -34,16 +34,23 @@
 
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.collect.ImmutableOpenMap;
 
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * Information about a snapshot shard size
+ *
+ * @opensearch.internal
+ */
 public class SnapshotShardSizeInfo {
 
-    public static final SnapshotShardSizeInfo EMPTY = new SnapshotShardSizeInfo(ImmutableOpenMap.of());
+    public static final SnapshotShardSizeInfo EMPTY = new SnapshotShardSizeInfo(Map.of());
 
-    private final ImmutableOpenMap<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes;
+    private final Map<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes;
 
-    public SnapshotShardSizeInfo(ImmutableOpenMap<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes) {
-        this.snapshotShardSizes = snapshotShardSizes;
+    public SnapshotShardSizeInfo(final Map<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes) {
+        this.snapshotShardSizes = Collections.unmodifiableMap(snapshotShardSizes);
     }
 
     public Long getShardSize(ShardRouting shardRouting) {
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotShardsService.java b/server/src/main/java/org/opensearch/snapshots/SnapshotShardsService.java
index b6c0b63efe3d3..d665a4aa579ad 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotShardsService.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotShardsService.java
@@ -32,13 +32,12 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.index.IndexCommit;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.SnapshotsInProgress;
@@ -48,19 +47,20 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.concurrent.GatedCloseable;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException;
+import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.snapshots.IndexShardSnapshotFailedException;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus.Stage;
 import org.opensearch.indices.IndicesService;
@@ -75,6 +75,7 @@
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.nio.file.NoSuchFileException;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -87,6 +88,8 @@
  * This service runs on data nodes and controls currently running shard snapshots on these nodes. It is responsible for
  * starting and stopping shard level snapshots.
  * See package level documentation of {@link org.opensearch.snapshots} for details.
+ *
+ * @opensearch.internal
  */
 public class SnapshotShardsService extends AbstractLifecycleComponent implements ClusterStateListener, IndexEventListener {
     private static final Logger logger = LogManager.getLogger(SnapshotShardsService.class);
@@ -103,7 +106,7 @@ public class SnapshotShardsService extends AbstractLifecycleComponent implements
 
     private final Map<Snapshot, Map<ShardId, IndexShardSnapshotStatus>> shardSnapshots = new HashMap<>();
 
-    // A map of snapshots to the shardIds that we already reported to the master as failed
+    // A map of snapshots to the shardIds that we already reported to the cluster-manager as failed
     private final TransportRequestDeduplicator<UpdateIndexShardSnapshotStatusRequest> remoteFailedRequestDeduplicator =
         new TransportRequestDeduplicator<>();
 
@@ -148,9 +151,9 @@ public void clusterChanged(ClusterChangedEvent event) {
                 }
             }
 
-            String previousMasterNodeId = event.previousState().nodes().getMasterNodeId();
-            String currentMasterNodeId = event.state().nodes().getMasterNodeId();
-            if (currentMasterNodeId != null && currentMasterNodeId.equals(previousMasterNodeId) == false) {
+            String previousClusterManagerNodeId = event.previousState().nodes().getClusterManagerNodeId();
+            String currentMasterNodeId = event.state().nodes().getClusterManagerNodeId();
+            if (currentMasterNodeId != null && currentMasterNodeId.equals(previousClusterManagerNodeId) == false) {
                 syncShardStatsOnNewMaster(event);
             }
 
@@ -225,10 +228,10 @@ private void startNewSnapshots(SnapshotsInProgress snapshotsInProgress) {
                 Map<ShardId, IndexShardSnapshotStatus> startedShards = null;
                 final Snapshot snapshot = entry.snapshot();
                 Map<ShardId, IndexShardSnapshotStatus> snapshotShards = shardSnapshots.getOrDefault(snapshot, emptyMap());
-                for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shard : entry.shards()) {
+                for (final Map.Entry<ShardId, ShardSnapshotStatus> shard : entry.shards().entrySet()) {
                     // Add all new shards to start processing on
-                    final ShardId shardId = shard.key;
-                    final ShardSnapshotStatus shardSnapshotStatus = shard.value;
+                    final ShardId shardId = shard.getKey();
+                    final ShardSnapshotStatus shardSnapshotStatus = shard.getValue();
                     if (shardSnapshotStatus.state() == ShardState.INIT
                         && localNodeId.equals(shardSnapshotStatus.nodeId())
                         && snapshotShards.containsKey(shardId) == false) {
@@ -247,13 +250,13 @@ private void startNewSnapshots(SnapshotsInProgress snapshotsInProgress) {
                 // Abort all running shards for this snapshot
                 final Snapshot snapshot = entry.snapshot();
                 Map<ShardId, IndexShardSnapshotStatus> snapshotShards = shardSnapshots.getOrDefault(snapshot, emptyMap());
-                for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shard : entry.shards()) {
-                    final IndexShardSnapshotStatus snapshotStatus = snapshotShards.get(shard.key);
+                for (final Map.Entry<ShardId, ShardSnapshotStatus> shard : entry.shards().entrySet()) {
+                    final IndexShardSnapshotStatus snapshotStatus = snapshotShards.get(shard.getKey());
                     if (snapshotStatus == null) {
                         // due to CS batching we might have missed the INIT state and straight went into ABORTED
-                        // notify master that abort has completed by moving to FAILED
-                        if (shard.value.state() == ShardState.ABORTED && localNodeId.equals(shard.value.nodeId())) {
-                            notifyFailedSnapshotShard(snapshot, shard.key, shard.value.reason());
+                        // notify cluster-manager that abort has completed by moving to FAILED
+                        if (shard.getValue().state() == ShardState.ABORTED && localNodeId.equals(shard.getValue().nodeId())) {
+                            notifyFailedSnapshotShard(snapshot, shard.getKey(), shard.getValue().reason());
                         }
                     } else {
                         snapshotStatus.abortIfNotCompleted("snapshot has been aborted");
@@ -274,47 +277,73 @@ private void startNewShards(SnapshotsInProgress.Entry entry, Map<ShardId, IndexS
                 final IndexShardSnapshotStatus snapshotStatus = shardEntry.getValue();
                 final IndexId indexId = indicesMap.get(shardId.getIndexName());
                 assert indexId != null;
-                assert SnapshotsService.useShardGenerations(entry.version())
-                    || ShardGenerations.fixShardGeneration(snapshotStatus.generation()) == null
-                    : "Found non-null, non-numeric shard generation ["
-                        + snapshotStatus.generation()
-                        + "] for snapshot with old-format compatibility";
-                snapshot(shardId, snapshot, indexId, entry.userMetadata(), snapshotStatus, entry.version(), new ActionListener<String>() {
-                    @Override
-                    public void onResponse(String newGeneration) {
-                        assert newGeneration != null;
-                        assert newGeneration.equals(snapshotStatus.generation());
-                        if (logger.isDebugEnabled()) {
-                            final IndexShardSnapshotStatus.Copy lastSnapshotStatus = snapshotStatus.asCopy();
-                            logger.debug(
-                                "snapshot [{}] completed to [{}] with [{}] at generation [{}]",
-                                snapshot,
-                                snapshot.getRepository(),
-                                lastSnapshotStatus,
-                                snapshotStatus.generation()
-                            );
-                        }
-                        notifySuccessfulSnapshotShard(snapshot, shardId, newGeneration);
-                    }
+                if (isRemoteSnapshot(shardId)) {
+                    // If the source of the data is another remote snapshot (i.e. searchable snapshot)
+                    // then no need to snapshot the shard and can immediately notify success.
+                    notifySuccessfulSnapshotShard(snapshot, shardId, snapshotStatus.generation());
+                } else {
+                    assert SnapshotsService.useShardGenerations(entry.version())
+                        || ShardGenerations.fixShardGeneration(snapshotStatus.generation()) == null
+                        : "Found non-null, non-numeric shard generation ["
+                            + snapshotStatus.generation()
+                            + "] for snapshot with old-format compatibility";
+                    snapshot(
+                        shardId,
+                        snapshot,
+                        indexId,
+                        entry.userMetadata(),
+                        snapshotStatus,
+                        entry.version(),
+                        entry.remoteStoreIndexShallowCopy(),
+                        new ActionListener<>() {
+                            @Override
+                            public void onResponse(String newGeneration) {
+                                assert newGeneration != null;
+                                assert newGeneration.equals(snapshotStatus.generation());
+                                if (logger.isDebugEnabled()) {
+                                    final IndexShardSnapshotStatus.Copy lastSnapshotStatus = snapshotStatus.asCopy();
+                                    logger.debug(
+                                        "snapshot [{}] completed to [{}] with [{}] at generation [{}]",
+                                        snapshot,
+                                        snapshot.getRepository(),
+                                        lastSnapshotStatus,
+                                        snapshotStatus.generation()
+                                    );
+                                }
+                                notifySuccessfulSnapshotShard(snapshot, shardId, newGeneration);
+                            }
 
-                    @Override
-                    public void onFailure(Exception e) {
-                        final String failure;
-                        if (e instanceof AbortedSnapshotException) {
-                            failure = "aborted";
-                            logger.debug(() -> new ParameterizedMessage("[{}][{}] aborted shard snapshot", shardId, snapshot), e);
-                        } else {
-                            failure = summarizeFailure(e);
-                            logger.warn(() -> new ParameterizedMessage("[{}][{}] failed to snapshot shard", shardId, snapshot), e);
+                            @Override
+                            public void onFailure(Exception e) {
+                                final String failure;
+                                if (e instanceof AbortedSnapshotException) {
+                                    failure = "aborted";
+                                    logger.debug(() -> new ParameterizedMessage("[{}][{}] aborted shard snapshot", shardId, snapshot), e);
+                                } else {
+                                    failure = summarizeFailure(e);
+                                    logger.warn(() -> new ParameterizedMessage("[{}][{}] failed to snapshot shard", shardId, snapshot), e);
+                                }
+                                snapshotStatus.moveToFailed(threadPool.absoluteTimeInMillis(), failure);
+                                notifyFailedSnapshotShard(snapshot, shardId, failure);
+                            }
                         }
-                        snapshotStatus.moveToFailed(threadPool.absoluteTimeInMillis(), failure);
-                        notifyFailedSnapshotShard(snapshot, shardId, failure);
-                    }
-                });
+                    );
+                }
             }
         });
     }
 
+    private boolean isRemoteSnapshot(ShardId shardId) {
+        final IndexService indexService = indicesService.indexService(shardId.getIndex());
+        if (indexService != null) {
+            final IndexShard shard = indexService.getShardOrNull(shardId.id());
+            if (shard != null) {
+                return shard.isRemoteSnapshot();
+            }
+        }
+        return false;
+    }
+
     // package private for testing
     static String summarizeFailure(Throwable t) {
         if (t.getCause() == null) {
@@ -350,6 +379,7 @@ private void snapshot(
         final Map<String, Object> userMetadata,
         final IndexShardSnapshotStatus snapshotStatus,
         Version version,
+        final boolean remoteStoreIndexShallowCopy,
         ActionListener<String> listener
     ) {
         try {
@@ -357,6 +387,12 @@ private void snapshot(
             if (indexShard.routingEntry().primary() == false) {
                 throw new IndexShardSnapshotFailedException(shardId, "snapshot should be performed only on primary");
             }
+            if (indexShard.indexSettings().isSegRepEnabled() && indexShard.isPrimaryMode() == false) {
+                throw new IndexShardSnapshotFailedException(
+                    shardId,
+                    "snapshot triggered on a new primary following failover and cannot proceed until promotion is complete"
+                );
+            }
             if (indexShard.routingEntry().relocating()) {
                 // do not snapshot when in the process of relocation of primaries so we won't get conflicts
                 throw new IndexShardSnapshotFailedException(shardId, "cannot snapshot while relocating");
@@ -371,21 +407,82 @@ private void snapshot(
             final Repository repository = repositoriesService.repository(snapshot.getRepository());
             GatedCloseable<IndexCommit> wrappedSnapshot = null;
             try {
-                // we flush first to make sure we get the latest writes snapshotted
-                wrappedSnapshot = indexShard.acquireLastIndexCommit(true);
-                final IndexCommit snapshotIndexCommit = wrappedSnapshot.get();
-                repository.snapshotShard(
-                    indexShard.store(),
-                    indexShard.mapperService(),
-                    snapshot.getSnapshotId(),
-                    indexId,
-                    wrappedSnapshot.get(),
-                    getShardStateId(indexShard, snapshotIndexCommit),
-                    snapshotStatus,
-                    version,
-                    userMetadata,
-                    ActionListener.runBefore(listener, wrappedSnapshot::close)
-                );
+                if (remoteStoreIndexShallowCopy && indexShard.indexSettings().isRemoteStoreEnabled()) {
+                    long startTime = threadPool.relativeTimeInMillis();
+                    long primaryTerm = indexShard.getOperationPrimaryTerm();
+                    // we flush first to make sure we get the latest writes snapshotted
+                    wrappedSnapshot = indexShard.acquireLastIndexCommitAndRefresh(true);
+                    IndexCommit snapshotIndexCommit = wrappedSnapshot.get();
+                    long commitGeneration = snapshotIndexCommit.getGeneration();
+                    try {
+                        indexShard.acquireLockOnCommitData(snapshot.getSnapshotId().getUUID(), primaryTerm, commitGeneration);
+                    } catch (NoSuchFileException e) {
+                        wrappedSnapshot.close();
+                        logger.warn(
+                            "Exception while acquiring lock on primaryTerm = {} and generation = {}",
+                            primaryTerm,
+                            commitGeneration
+                        );
+                        indexShard.flush(new FlushRequest(shardId.getIndexName()).force(true));
+                        wrappedSnapshot = indexShard.acquireLastIndexCommit(false);
+                        snapshotIndexCommit = wrappedSnapshot.get();
+                        commitGeneration = snapshotIndexCommit.getGeneration();
+                        indexShard.acquireLockOnCommitData(snapshot.getSnapshotId().getUUID(), primaryTerm, commitGeneration);
+                    }
+                    try {
+                        repository.snapshotRemoteStoreIndexShard(
+                            indexShard.store(),
+                            snapshot.getSnapshotId(),
+                            indexId,
+                            snapshotIndexCommit,
+                            getShardStateId(indexShard, snapshotIndexCommit),
+                            snapshotStatus,
+                            primaryTerm,
+                            startTime,
+                            ActionListener.runBefore(listener, wrappedSnapshot::close)
+                        );
+                    } catch (IndexShardSnapshotFailedException e) {
+                        logger.error(
+                            "Shallow Copy Snapshot Failed for Shard ["
+                                + indexId.getName()
+                                + "]["
+                                + shardId.getId()
+                                + "] for snapshot "
+                                + snapshot.getSnapshotId()
+                                + ", releasing acquired lock from remote store"
+                        );
+                        indexShard.releaseLockOnCommitData(snapshot.getSnapshotId().getUUID(), primaryTerm, commitGeneration);
+                        throw e;
+                    }
+                    long endTime = threadPool.relativeTimeInMillis();
+                    logger.debug(
+                        "Time taken (in milliseconds) to complete shallow copy snapshot, "
+                            + "for index "
+                            + indexId.getName()
+                            + ", shard "
+                            + shardId.getId()
+                            + " and snapshot "
+                            + snapshot.getSnapshotId()
+                            + " is "
+                            + (endTime - startTime)
+                    );
+                } else {
+                    // we flush first to make sure we get the latest writes snapshotted
+                    wrappedSnapshot = indexShard.acquireLastIndexCommit(true);
+                    final IndexCommit snapshotIndexCommit = wrappedSnapshot.get();
+                    repository.snapshotShard(
+                        indexShard.store(),
+                        indexShard.mapperService(),
+                        snapshot.getSnapshotId(),
+                        indexId,
+                        wrappedSnapshot.get(),
+                        getShardStateId(indexShard, snapshotIndexCommit),
+                        snapshotStatus,
+                        version,
+                        userMetadata,
+                        ActionListener.runBefore(listener, wrappedSnapshot::close)
+                    );
+                }
             } catch (Exception e) {
                 IOUtils.close(wrappedSnapshot);
                 throw e;
@@ -424,7 +521,7 @@ private static String getShardStateId(IndexShard indexShard, IndexCommit snapsho
     }
 
     /**
-     * Checks if any shards were processed that the new master doesn't know about
+     * Checks if any shards were processed that the new cluster-manager doesn't know about
      */
     private void syncShardStatsOnNewMaster(ClusterChangedEvent event) {
         SnapshotsInProgress snapshotsInProgress = event.state().custom(SnapshotsInProgress.TYPE);
@@ -433,35 +530,35 @@ private void syncShardStatsOnNewMaster(ClusterChangedEvent event) {
         }
 
         // Clear request deduplicator since we need to send all requests that were potentially not handled by the previous
-        // master again
+        // cluster-manager again
         remoteFailedRequestDeduplicator.clear();
         for (SnapshotsInProgress.Entry snapshot : snapshotsInProgress.entries()) {
             if (snapshot.state() == State.STARTED || snapshot.state() == State.ABORTED) {
                 Map<ShardId, IndexShardSnapshotStatus> localShards = currentSnapshotShards(snapshot.snapshot());
                 if (localShards != null) {
-                    ImmutableOpenMap<ShardId, ShardSnapshotStatus> masterShards = snapshot.shards();
+                    final Map<ShardId, ShardSnapshotStatus> masterShards = snapshot.shards();
                     for (Map.Entry<ShardId, IndexShardSnapshotStatus> localShard : localShards.entrySet()) {
                         ShardId shardId = localShard.getKey();
                         ShardSnapshotStatus masterShard = masterShards.get(shardId);
                         if (masterShard != null && masterShard.state().completed() == false) {
                             final IndexShardSnapshotStatus.Copy indexShardSnapshotStatus = localShard.getValue().asCopy();
                             final Stage stage = indexShardSnapshotStatus.getStage();
-                            // Master knows about the shard and thinks it has not completed
+                            // cluster-manager knows about the shard and thinks it has not completed
                             if (stage == Stage.DONE) {
-                                // but we think the shard is done - we need to make new master know that the shard is done
+                                // but we think the shard is done - we need to make new cluster-manager know that the shard is done
                                 logger.debug(
-                                    "[{}] new master thinks the shard [{}] is not completed but the shard is done locally, "
-                                        + "updating status on the master",
+                                    "[{}] new cluster-manager thinks the shard [{}] is not completed but the shard is done locally, "
+                                        + "updating status on the cluster-manager",
                                     snapshot.snapshot(),
                                     shardId
                                 );
                                 notifySuccessfulSnapshotShard(snapshot.snapshot(), shardId, localShard.getValue().generation());
 
                             } else if (stage == Stage.FAILURE) {
-                                // but we think the shard failed - we need to make new master know that the shard failed
+                                // but we think the shard failed - we need to make new cluster-manager know that the shard failed
                                 logger.debug(
-                                    "[{}] new master thinks the shard [{}] is not completed but the shard failed locally, "
-                                        + "updating status on master",
+                                    "[{}] new cluster-manager thinks the shard [{}] is not completed but the shard failed locally, "
+                                        + "updating status on cluster-manager",
                                     snapshot.snapshot(),
                                     shardId
                                 );
@@ -474,7 +571,7 @@ private void syncShardStatsOnNewMaster(ClusterChangedEvent event) {
         }
     }
 
-    /** Notify the master node that the given shard has been successfully snapshotted **/
+    /** Notify the cluster-manager node that the given shard has been successfully snapshotted **/
     private void notifySuccessfulSnapshotShard(final Snapshot snapshot, final ShardId shardId, String generation) {
         assert generation != null;
         sendSnapshotShardUpdate(
@@ -484,7 +581,7 @@ private void notifySuccessfulSnapshotShard(final Snapshot snapshot, final ShardI
         );
     }
 
-    /** Notify the master node that the given shard failed to be snapshotted **/
+    /** Notify the cluster-manager node that the given shard failed to be snapshotted **/
     private void notifyFailedSnapshotShard(final Snapshot snapshot, final ShardId shardId, final String failure) {
         sendSnapshotShardUpdate(
             snapshot,
@@ -493,7 +590,7 @@ private void notifyFailedSnapshotShard(final Snapshot snapshot, final ShardId sh
         );
     }
 
-    /** Updates the shard snapshot status by sending a {@link UpdateIndexShardSnapshotStatusRequest} to the master node */
+    /** Updates the shard snapshot status by sending a {@link UpdateIndexShardSnapshotStatusRequest} to the cluster-manager node */
     private void sendSnapshotShardUpdate(final Snapshot snapshot, final ShardId shardId, final ShardSnapshotStatus status) {
         remoteFailedRequestDeduplicator.executeOnce(
             new UpdateIndexShardSnapshotStatusRequest(snapshot, shardId, status),
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotState.java b/server/src/main/java/org/opensearch/snapshots/SnapshotState.java
index 75718481edce6..dd1b3ebb8404d 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotState.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotState.java
@@ -34,6 +34,8 @@
 
 /**
  * Represents the state that a snapshot can be in
+ *
+ * @opensearch.internal
  */
 public enum SnapshotState {
     /**
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotUtils.java b/server/src/main/java/org/opensearch/snapshots/SnapshotUtils.java
index 4515671a9fd10..e7338a29cafeb 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotUtils.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotUtils.java
@@ -32,19 +32,28 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.IndexSettings;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Snapshot utilities
+ *
+ * @opensearch.internal
  */
 public class SnapshotUtils {
 
@@ -60,9 +69,17 @@ public static List<String> filterIndices(List<String> availableIndices, String[]
         if (IndexNameExpressionResolver.isAllIndices(Arrays.asList(selectedIndices))) {
             return availableIndices;
         }
+
+        // Move the exclusions to end of list to ensure they are processed
+        // after explicitly selected indices are chosen.
+        final List<String> excludesAtEndSelectedIndices = Stream.concat(
+            Arrays.stream(selectedIndices).filter(s -> s.isEmpty() || s.charAt(0) != '-'),
+            Arrays.stream(selectedIndices).filter(s -> !s.isEmpty() && s.charAt(0) == '-')
+        ).collect(Collectors.toUnmodifiableList());
+
         Set<String> result = null;
-        for (int i = 0; i < selectedIndices.length; i++) {
-            String indexOrPattern = selectedIndices[i];
+        for (int i = 0; i < excludesAtEndSelectedIndices.size(); i++) {
+            String indexOrPattern = excludesAtEndSelectedIndices.get(i);
             boolean add = true;
             if (!indexOrPattern.isEmpty()) {
                 if (availableIndices.contains(indexOrPattern)) {
@@ -80,7 +97,9 @@ public static List<String> filterIndices(List<String> availableIndices, String[]
                         result = new HashSet<>();
                     }
                 } else if (indexOrPattern.charAt(0) == '-') {
-                    // if its the first, fill it with all the indices...
+                    // If the first index pattern is an exclusion, then all patterns are exclusions due to the
+                    // reordering logic above. In this case, the request is interpreted as "include all indexes except
+                    // those matching the exclusions" so we add all indices here and then remove the ones that match the exclusion patterns.
                     if (i == 0) {
                         result = new HashSet<>(availableIndices);
                     }
@@ -133,4 +152,38 @@ public static List<String> filterIndices(List<String> availableIndices, String[]
         }
         return Collections.unmodifiableList(new ArrayList<>(result));
     }
+
+    /**
+     * Validates if there are any remote snapshots backing an index
+     * @param metadata index metadata from cluster state
+     * @param snapshotIds list of snapshot Ids to be verified
+     * @param repoName repo name for which the verification is being done
+     */
+    public static void validateSnapshotsBackingAnyIndex(
+        final Map<String, IndexMetadata> metadata,
+        List<SnapshotId> snapshotIds,
+        String repoName
+    ) {
+        final Map<String, SnapshotId> uuidToSnapshotId = new HashMap<>();
+        final Set<String> snapshotsToBeNotDeleted = new HashSet<>();
+        snapshotIds.forEach(snapshotId -> uuidToSnapshotId.put(snapshotId.getUUID(), snapshotId));
+
+        for (final IndexMetadata indexMetadata : metadata.values()) {
+            String storeType = indexMetadata.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey());
+            if (IndexModule.Type.REMOTE_SNAPSHOT.match(storeType)) {
+                String snapshotId = indexMetadata.getSettings().get(IndexSettings.SEARCHABLE_SNAPSHOT_ID_UUID.getKey());
+                if (uuidToSnapshotId.get(snapshotId) != null) {
+                    snapshotsToBeNotDeleted.add(uuidToSnapshotId.get(snapshotId).getName());
+                }
+            }
+        }
+
+        if (!snapshotsToBeNotDeleted.isEmpty()) {
+            throw new SnapshotInUseDeletionException(
+                repoName,
+                snapshotsToBeNotDeleted.toString(),
+                "These remote snapshots are backing some indices and hence can't be deleted! No snapshots were deleted."
+            );
+        }
+    }
 }
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotsInfoService.java b/server/src/main/java/org/opensearch/snapshots/SnapshotsInfoService.java
index 376bd5e05742f..5f16b6e20d3af 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotsInfoService.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotsInfoService.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.snapshots;
 
+/**
+ * Base interface for shard information
+ *
+ * @opensearch.internal
+ */
 @FunctionalInterface
 public interface SnapshotsInfoService {
     SnapshotShardSizeInfo snapshotShardSizes();
diff --git a/server/src/main/java/org/opensearch/snapshots/SnapshotsService.java b/server/src/main/java/org/opensearch/snapshots/SnapshotsService.java
index 122c13337fa70..0a1ba2486cba6 100644
--- a/server/src/main/java/org/opensearch/snapshots/SnapshotsService.java
+++ b/server/src/main/java/org/opensearch/snapshots/SnapshotsService.java
@@ -32,15 +32,12 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.admin.cluster.snapshots.clone.CloneSnapshotRequest;
@@ -48,7 +45,7 @@
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.GroupedActionListener;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateApplier;
@@ -56,7 +53,7 @@
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.ClusterStateTaskListener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.RepositoryCleanupInProgress;
 import org.opensearch.cluster.RestoreInProgress;
 import org.opensearch.cluster.SnapshotDeletionsInProgress;
@@ -77,22 +74,25 @@
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterManagerTaskKeys;
+import org.opensearch.cluster.service.ClusterManagerTaskThrottler;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
@@ -132,11 +132,15 @@
 import static java.util.Collections.emptySet;
 import static java.util.Collections.unmodifiableList;
 import static org.opensearch.cluster.SnapshotsInProgress.completed;
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY;
+import static org.opensearch.snapshots.SnapshotUtils.validateSnapshotsBackingAnyIndex;
 
 /**
- * Service responsible for creating snapshots. This service runs all the steps executed on the master node during snapshot creation and
+ * Service responsible for creating snapshots. This service runs all the steps executed on the cluster-manager node during snapshot creation and
  * deletion.
  * See package level documentation of {@link org.opensearch.snapshots} for details.
+ *
+ * @opensearch.internal
  */
 public class SnapshotsService extends AbstractLifecycleComponent implements ClusterStateApplier {
 
@@ -168,6 +172,8 @@ public class SnapshotsService extends AbstractLifecycleComponent implements Clus
 
     private final RepositoriesService repositoriesService;
 
+    private final RemoteStoreLockManagerFactory remoteStoreLockManagerFactory;
+
     private final ThreadPool threadPool;
 
     private final Map<Snapshot, List<ActionListener<Tuple<RepositoryData, SnapshotInfo>>>> snapshotCompletionListeners =
@@ -196,6 +202,10 @@ public class SnapshotsService extends AbstractLifecycleComponent implements Clus
 
     private final OngoingRepositoryOperations repositoryOperations = new OngoingRepositoryOperations();
 
+    private final ClusterManagerTaskThrottler.ThrottlingKey createSnapshotTaskKey;
+    private final ClusterManagerTaskThrottler.ThrottlingKey deleteSnapshotTaskKey;
+    private static ClusterManagerTaskThrottler.ThrottlingKey updateSnapshotStateTaskKey;
+
     /**
      * Setting that specifies the maximum number of allowed concurrent snapshot create and delete operations in the
      * cluster state. The number of concurrent operations in a cluster state is defined as the sum of the sizes of
@@ -222,6 +232,7 @@ public SnapshotsService(
         this.clusterService = clusterService;
         this.indexNameExpressionResolver = indexNameExpressionResolver;
         this.repositoriesService = repositoriesService;
+        this.remoteStoreLockManagerFactory = new RemoteStoreLockManagerFactory(() -> repositoriesService);
         this.threadPool = transportService.getThreadPool();
         this.transportService = transportService;
 
@@ -233,13 +244,18 @@ public SnapshotsService(
             actionFilters,
             indexNameExpressionResolver
         );
-        if (DiscoveryNode.isMasterNode(settings)) {
+        if (DiscoveryNode.isClusterManagerNode(settings)) {
             // addLowPriorityApplier to make sure that Repository will be created before snapshot
             clusterService.addLowPriorityApplier(this);
             maxConcurrentOperations = MAX_CONCURRENT_SNAPSHOT_OPERATIONS_SETTING.get(settings);
             clusterService.getClusterSettings()
                 .addSettingsUpdateConsumer(MAX_CONCURRENT_SNAPSHOT_OPERATIONS_SETTING, i -> maxConcurrentOperations = i);
         }
+
+        // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
+        createSnapshotTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.CREATE_SNAPSHOT_KEY, true);
+        deleteSnapshotTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.DELETE_SNAPSHOT_KEY, true);
+        updateSnapshotStateTaskKey = clusterService.registerClusterManagerTask(ClusterManagerTaskKeys.UPDATE_SNAPSHOT_STATE_KEY, true);
     }
 
     /**
@@ -303,8 +319,8 @@ public ClusterState execute(ClusterState currentState) {
                 }
                 SnapshotsInProgress snapshots = currentState.custom(SnapshotsInProgress.TYPE);
                 // Fail if there are any concurrently running snapshots. The only exception to this being a snapshot in INIT state from a
-                // previous master that we can simply ignore and remove from the cluster state because we would clean it up from the
-                // cluster state anyway in #applyClusterState.
+                // previous cluster-manager that we can simply ignore and remove from the cluster state because we would clean it up from
+                // the cluster state anyway in #applyClusterState.
                 if (snapshots != null
                     && snapshots.entries()
                         .stream()
@@ -323,6 +339,7 @@ public ClusterState execute(ClusterState currentState) {
                 );
 
                 logger.trace("[{}][{}] creating snapshot for indices [{}]", repositoryName, snapshotName, indices);
+                boolean remoteStoreIndexShallowCopy = REMOTE_STORE_INDEX_SHALLOW_COPY.get(repository.getMetadata().settings());
                 newEntry = new SnapshotsInProgress.Entry(
                     new Snapshot(repositoryName, snapshotId),
                     request.includeGlobalState(),
@@ -332,9 +349,10 @@ public ClusterState execute(ClusterState currentState) {
                     dataStreams,
                     threadPool.absoluteTimeInMillis(),
                     RepositoryData.UNKNOWN_REPO_GEN,
-                    ImmutableOpenMap.of(),
+                    Map.of(),
                     userMeta,
-                    Version.CURRENT
+                    Version.CURRENT,
+                    remoteStoreIndexShallowCopy
                 );
                 initializingSnapshots.add(newEntry.snapshot());
                 snapshots = SnapshotsInProgress.of(Collections.singletonList(newEntry));
@@ -375,7 +393,7 @@ public void onFailure(final Exception e) {
 
             @Override
             public TimeValue timeout() {
-                return request.masterNodeTimeout();
+                return request.clusterManagerNodeTimeout();
             }
         });
     }
@@ -411,6 +429,7 @@ public void createSnapshot(final CreateSnapshotRequest request, final ActionList
         // retries
         final SnapshotId snapshotId = new SnapshotId(snapshotName, UUIDs.randomBase64UUID()); // new UUID for the snapshot
         Repository repository = repositoriesService.repository(request.repository());
+
         if (repository.isReadOnly()) {
             listener.onFailure(new RepositoryException(repository.getMetadata().name(), "cannot create snapshot in a readonly repository"));
             return;
@@ -452,7 +471,8 @@ public ClusterState execute(ClusterState currentState) {
                     );
                 }
                 // Fail if there are any concurrently running snapshots. The only exception to this being a snapshot in INIT state from a
-                // previous master that we can simply ignore and remove from the cluster state because we would clean it up from the
+                // previous cluster-manager that we can simply ignore and remove from the cluster state because we would clean it up from
+                // the
                 // cluster state anyway in #applyClusterState.
                 if (concurrentOperationsAllowed == false && runningSnapshots.stream().anyMatch(entry -> entry.state() != State.INIT)) {
                     throw new ConcurrentSnapshotExecutionException(repositoryName, snapshotName, " a snapshot is already running");
@@ -475,7 +495,7 @@ public ClusterState execute(ClusterState currentState) {
                     getInFlightIndexIds(runningSnapshots, repositoryName)
                 );
                 final Version version = minCompatibleVersion(currentState.nodes().getMinNodeVersion(), repositoryData, null);
-                ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards = shards(
+                final Map<ShardId, ShardSnapshotStatus> shards = shards(
                     snapshots,
                     deletionsInProgress,
                     currentState.metadata(),
@@ -487,9 +507,9 @@ public ClusterState execute(ClusterState currentState) {
                 );
                 if (request.partial() == false) {
                     Set<String> missing = new HashSet<>();
-                    for (ObjectObjectCursor<ShardId, SnapshotsInProgress.ShardSnapshotStatus> entry : shards) {
-                        if (entry.value.state() == ShardState.MISSING) {
-                            missing.add(entry.key.getIndex().getName());
+                    for (final Map.Entry<ShardId, SnapshotsInProgress.ShardSnapshotStatus> entry : shards.entrySet()) {
+                        if (entry.getValue().state() == ShardState.MISSING) {
+                            missing.add(entry.getKey().getIndex().getName());
                         }
                     }
                     if (missing.isEmpty() == false) {
@@ -499,6 +519,8 @@ public ClusterState execute(ClusterState currentState) {
                         );
                     }
                 }
+
+                boolean remoteStoreIndexShallowCopy = REMOTE_STORE_INDEX_SHALLOW_COPY.get(repository.getMetadata().settings());
                 newEntry = SnapshotsInProgress.startedEntry(
                     new Snapshot(repositoryName, snapshotId),
                     request.includeGlobalState(),
@@ -509,7 +531,8 @@ public ClusterState execute(ClusterState currentState) {
                     repositoryData.getGenId(),
                     shards,
                     userMeta,
-                    version
+                    version,
+                    remoteStoreIndexShallowCopy
                 );
                 final List<SnapshotsInProgress.Entry> newEntries = new ArrayList<>(runningSnapshots);
                 newEntries.add(newEntry);
@@ -524,6 +547,11 @@ public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return createSnapshotTaskKey;
+            }
+
             @Override
             public void clusterStateProcessed(String source, ClusterState oldState, final ClusterState newState) {
                 try {
@@ -538,7 +566,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, final Cl
 
             @Override
             public TimeValue timeout() {
-                return request.masterNodeTimeout();
+                return request.clusterManagerNodeTimeout();
             }
         }, "create_snapshot [" + snapshotName + ']', listener::onFailure);
     }
@@ -660,7 +688,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, final Cl
 
             @Override
             public TimeValue timeout() {
-                return request.masterNodeTimeout();
+                return request.clusterManagerNodeTimeout();
             }
         }, "clone_snapshot [" + request.source() + "][" + snapshotName + ']', listener::onFailure);
     }
@@ -754,7 +782,7 @@ public ClusterState execute(ClusterState currentState) {
                 final ShardGenerations shardGenerations = repoData.shardGenerations();
                 for (int i = 0; i < updatedEntries.size(); i++) {
                     if (cloneEntry.snapshot().equals(updatedEntries.get(i).snapshot())) {
-                        final ImmutableOpenMap.Builder<RepositoryShardId, ShardSnapshotStatus> clonesBuilder = ImmutableOpenMap.builder();
+                        final Map<RepositoryShardId, ShardSnapshotStatus> clonesBuilder = new HashMap<>();
                         final InFlightShardSnapshotStates inFlightShardStates = InFlightShardSnapshotStates.forRepo(
                             repoName,
                             snapshotsInProgress.entries()
@@ -776,7 +804,11 @@ public ClusterState execute(ClusterState currentState) {
                                 }
                             }
                         }
-                        updatedEntry = cloneEntry.withClones(clonesBuilder.build());
+                        updatedEntry = cloneEntry.withClones(clonesBuilder)
+                            .withRemoteStoreIndexShallowCopy(
+                                Boolean.TRUE.equals(snapshotInfoListener.result().isRemoteStoreIndexShallowCopyEnabled())
+                            );
+                        ;
                         updatedEntries.set(i, updatedEntry);
                         changed = true;
                         break;
@@ -798,16 +830,17 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                 if (updatedEntry != null) {
                     final Snapshot target = updatedEntry.snapshot();
                     final SnapshotId sourceSnapshot = updatedEntry.source();
-                    for (ObjectObjectCursor<RepositoryShardId, ShardSnapshotStatus> indexClone : updatedEntry.clones()) {
-                        final ShardSnapshotStatus shardStatusBefore = indexClone.value;
+                    for (final Map.Entry<RepositoryShardId, ShardSnapshotStatus> indexClone : updatedEntry.clones().entrySet()) {
+                        final ShardSnapshotStatus shardStatusBefore = indexClone.getValue();
                         if (shardStatusBefore.state() != ShardState.INIT) {
                             continue;
                         }
-                        final RepositoryShardId repoShardId = indexClone.key;
-                        runReadyClone(target, sourceSnapshot, shardStatusBefore, repoShardId, repository);
+                        final RepositoryShardId repoShardId = indexClone.getKey();
+                        final boolean remoteStoreIndexShallowCopy = Boolean.TRUE.equals(updatedEntry.remoteStoreIndexShallowCopy());
+                        runReadyClone(target, sourceSnapshot, shardStatusBefore, repoShardId, repository, remoteStoreIndexShallowCopy);
                     }
                 } else {
-                    // Extremely unlikely corner case of master failing over between between starting the clone and
+                    // Extremely unlikely corner case of cluster-manager failing over between between starting the clone and
                     // starting shard clones.
                     logger.warn("Did not find expected entry [{}] in the cluster state", cloneEntry);
                 }
@@ -822,60 +855,112 @@ private void runReadyClone(
         SnapshotId sourceSnapshot,
         ShardSnapshotStatus shardStatusBefore,
         RepositoryShardId repoShardId,
-        Repository repository
+        Repository repository,
+        boolean remoteStoreIndexShallowCopy
     ) {
-        final SnapshotId targetSnapshot = target.getSnapshotId();
-        final String localNodeId = clusterService.localNode().getId();
-        if (currentlyCloning.add(repoShardId)) {
-            repository.cloneShardSnapshot(
-                sourceSnapshot,
-                targetSnapshot,
-                repoShardId,
-                shardStatusBefore.generation(),
-                ActionListener.wrap(
-                    generation -> innerUpdateSnapshotState(
-                        new ShardSnapshotUpdate(target, repoShardId, new ShardSnapshotStatus(localNodeId, ShardState.SUCCESS, generation)),
-                        ActionListener.runBefore(
-                            ActionListener.wrap(
-                                v -> logger.trace(
-                                    "Marked [{}] as successfully cloned from [{}] to [{}]",
+        final Executor executor = threadPool.executor(ThreadPool.Names.SNAPSHOT);
+        executor.execute(new AbstractRunnable() {
+            @Override
+            public void onFailure(Exception e) {
+                logger.warn(
+                    "Failed to get repository data while cloning shard [{}] from [{}] to [{}]",
+                    repoShardId,
+                    sourceSnapshot,
+                    target.getSnapshotId()
+                );
+                failCloneShardAndUpdateClusterState(target, sourceSnapshot, repoShardId);
+            }
+
+            @Override
+            protected void doRun() {
+                final String localNodeId = clusterService.localNode().getId();
+                repository.getRepositoryData(ActionListener.wrap(repositoryData -> {
+                    try {
+                        final IndexMetadata indexMetadata = repository.getSnapshotIndexMetaData(
+                            repositoryData,
+                            sourceSnapshot,
+                            repoShardId.index()
+                        );
+                        final boolean cloneRemoteStoreIndexShardSnapshot = remoteStoreIndexShallowCopy
+                            && indexMetadata.getSettings().getAsBoolean(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false);
+                        final SnapshotId targetSnapshot = target.getSnapshotId();
+                        final ActionListener<String> listener = ActionListener.wrap(
+                            generation -> innerUpdateSnapshotState(
+                                new ShardSnapshotUpdate(
+                                    target,
                                     repoShardId,
-                                    sourceSnapshot,
-                                    targetSnapshot
+                                    new ShardSnapshotStatus(localNodeId, ShardState.SUCCESS, generation)
                                 ),
-                                e -> {
-                                    logger.warn("Cluster state update after successful shard clone [{}] failed", repoShardId);
-                                    failAllListenersOnMasterFailOver(e);
-                                }
+                                ActionListener.runBefore(
+                                    ActionListener.wrap(
+                                        v -> logger.trace(
+                                            "Marked [{}] as successfully cloned from [{}] to [{}]",
+                                            repoShardId,
+                                            sourceSnapshot,
+                                            targetSnapshot
+                                        ),
+                                        e -> {
+                                            logger.warn("Cluster state update after successful shard clone [{}] failed", repoShardId);
+                                            failAllListenersOnMasterFailOver(e);
+                                        }
+                                    ),
+                                    () -> currentlyCloning.remove(repoShardId)
+                                )
                             ),
-                            () -> currentlyCloning.remove(repoShardId)
-                        )
-                    ),
-                    e -> innerUpdateSnapshotState(
-                        new ShardSnapshotUpdate(
-                            target,
-                            repoShardId,
-                            new ShardSnapshotStatus(localNodeId, ShardState.FAILED, "failed to clone shard snapshot", null)
-                        ),
-                        ActionListener.runBefore(
-                            ActionListener.wrap(
-                                v -> logger.trace(
-                                    "Marked [{}] as failed clone from [{}] to [{}]",
+                            e -> {
+                                logger.warn("Exception [{}] while trying to clone shard [{}]", e, repoShardId);
+                                failCloneShardAndUpdateClusterState(target, sourceSnapshot, repoShardId);
+                            }
+                        );
+                        if (currentlyCloning.add(repoShardId)) {
+                            if (cloneRemoteStoreIndexShardSnapshot) {
+                                repository.cloneRemoteStoreIndexShardSnapshot(
+                                    sourceSnapshot,
+                                    targetSnapshot,
                                     repoShardId,
+                                    shardStatusBefore.generation(),
+                                    remoteStoreLockManagerFactory,
+                                    listener
+                                );
+                            } else {
+                                repository.cloneShardSnapshot(
                                     sourceSnapshot,
-                                    targetSnapshot
-                                ),
-                                ex -> {
-                                    logger.warn("Cluster state update after failed shard clone [{}] failed", repoShardId);
-                                    failAllListenersOnMasterFailOver(ex);
-                                }
-                            ),
-                            () -> currentlyCloning.remove(repoShardId)
-                        )
-                    )
-                )
-            );
-        }
+                                    targetSnapshot,
+                                    repoShardId,
+                                    shardStatusBefore.generation(),
+                                    listener
+                                );
+                            }
+                        }
+                    } catch (IOException e) {
+                        logger.warn("Failed to get index-metadata from repository data for index [{}]", repoShardId.index().getName());
+                        failCloneShardAndUpdateClusterState(target, sourceSnapshot, repoShardId);
+                    }
+                }, this::onFailure));
+            }
+        });
+    }
+
+    private void failCloneShardAndUpdateClusterState(Snapshot target, SnapshotId sourceSnapshot, RepositoryShardId repoShardId) {
+        // Stale blobs/lock-files will be cleaned up during delete/cleanup operation.
+        final String localNodeId = clusterService.localNode().getId();
+        innerUpdateSnapshotState(
+            new ShardSnapshotUpdate(
+                target,
+                repoShardId,
+                new ShardSnapshotStatus(localNodeId, ShardState.FAILED, "failed to clone shard snapshot", null)
+            ),
+            ActionListener.runBefore(
+                ActionListener.wrap(
+                    v -> logger.trace("Marked [{}] as failed clone from [{}] to [{}]", repoShardId, sourceSnapshot, target.getSnapshotId()),
+                    ex -> {
+                        logger.warn("Cluster state update after failed shard clone [{}] failed", repoShardId);
+                        failAllListenersOnMasterFailOver(ex);
+                    }
+                ),
+                () -> currentlyCloning.remove(repoShardId)
+            )
+        );
     }
 
     private void ensureBelowConcurrencyLimit(
@@ -986,8 +1071,10 @@ protected void doRun() {
                         );
                     }
                     if (clusterState.nodes().getMinNodeVersion().onOrAfter(NO_REPO_INITIALIZE_VERSION) == false) {
-                        // In mixed version clusters we initialize the snapshot in the repository so that in case of a master failover to an
-                        // older version master node snapshot finalization (that assumes initializeSnapshot was called) produces a valid
+                        // In mixed version clusters we initialize the snapshot in the repository so that in case of a cluster-manager
+                        // failover to an
+                        // older version cluster-manager node snapshot finalization (that assumes initializeSnapshot was called) produces a
+                        // valid
                         // snapshot.
                         repository.initializeSnapshot(
                             snapshot.snapshot().getSnapshotId(),
@@ -1010,9 +1097,10 @@ protected void doRun() {
                                 Collections.emptyList(),
                                 threadPool.absoluteTimeInMillis(),
                                 repositoryData.getGenId(),
-                                ImmutableOpenMap.of(),
+                                Map.of(),
                                 snapshot.userMetadata(),
-                                version
+                                version,
+                                snapshot.remoteStoreIndexShallowCopy()
                             ),
                             clusterState.metadata(),
                             repositoryData
@@ -1038,7 +1126,7 @@ public ClusterState execute(ClusterState currentState) {
                                 } else {
                                     final List<IndexId> indexIds = repositoryData.resolveNewIndices(indices, Collections.emptyMap());
                                     // Replace the snapshot that was just initialized
-                                    ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards = shards(
+                                    final Map<ShardId, ShardSnapshotStatus> shards = shards(
                                         snapshots,
                                         currentState.custom(SnapshotDeletionsInProgress.TYPE, SnapshotDeletionsInProgress.EMPTY),
                                         currentState.metadata(),
@@ -1115,12 +1203,15 @@ public void onFailure(String source, Exception e) {
                         }
 
                         @Override
-                        public void onNoLongerMaster(String source) {
-                            // We are not longer a master - we shouldn't try to do any cleanup
-                            // The new master will take care of it
-                            logger.warn("[{}] failed to create snapshot - no longer a master", snapshot.snapshot().getSnapshotId());
+                        public void onNoLongerClusterManager(String source) {
+                            // We are not longer a cluster-manager - we shouldn't try to do any cleanup
+                            // The new cluster-manager will take care of it
+                            logger.warn(
+                                "[{}] failed to create snapshot - no longer a cluster-manager",
+                                snapshot.snapshot().getSnapshotId()
+                            );
                             userCreateSnapshotListener.onFailure(
-                                new SnapshotException(snapshot.snapshot(), "master changed during snapshot initialization")
+                                new SnapshotException(snapshot.snapshot(), "cluster-manager changed during snapshot initialization")
                             );
                         }
 
@@ -1173,7 +1264,7 @@ public void onFailure(@Nullable Exception e) {
             userCreateSnapshotListener.onFailure(ExceptionsHelper.useOrSuppress(e, this.e));
         }
 
-        public void onNoLongerMaster() {
+        public void onNoLongerClusterManager() {
             userCreateSnapshotListener.onFailure(e);
         }
     }
@@ -1183,21 +1274,19 @@ private static ShardGenerations buildGenerations(SnapshotsInProgress.Entry snaps
         final Map<String, IndexId> indexLookup = new HashMap<>();
         snapshot.indices().forEach(idx -> indexLookup.put(idx.getName(), idx));
         if (snapshot.isClone()) {
-            snapshot.clones().forEach(c -> {
-                final IndexId indexId = indexLookup.get(c.key.indexName());
-                builder.put(indexId, c.key.shardId(), c.value.generation());
+            snapshot.clones().forEach((id, status) -> {
+                final IndexId indexId = indexLookup.get(id.indexName());
+                builder.put(indexId, id.shardId(), status.generation());
             });
         } else {
-            snapshot.shards().forEach(c -> {
-                if (metadata.index(c.key.getIndex()) == null) {
-                    assert snapshot.partial() : "Index ["
-                        + c.key.getIndex()
-                        + "] was deleted during a snapshot but snapshot was not partial.";
+            snapshot.shards().forEach((id, status) -> {
+                if (metadata.index(id.getIndex()) == null) {
+                    assert snapshot.partial() : "Index [" + id.getIndex() + "] was deleted during a snapshot but snapshot was not partial.";
                     return;
                 }
-                final IndexId indexId = indexLookup.get(c.key.getIndexName());
+                final IndexId indexId = indexLookup.get(id.getIndexName());
                 if (indexId != null) {
-                    builder.put(indexId, c.key.id(), c.value.generation());
+                    builder.put(indexId, id.id(), status.generation());
                 }
             });
         }
@@ -1238,7 +1327,7 @@ private static Metadata metadataForSnapshot(SnapshotsInProgress.Entry snapshot,
     /**
      * Returns status of the currently running snapshots
      * <p>
-     * This method is executed on master node
+     * This method is executed on cluster-manager node
      * </p>
      *
      * @param snapshotsInProgress snapshots in progress in the cluster state
@@ -1297,21 +1386,23 @@ public static List<SnapshotsInProgress.Entry> currentSnapshots(
     @Override
     public void applyClusterState(ClusterChangedEvent event) {
         try {
-            if (event.localNodeMaster()) {
-                // We don't remove old master when master flips anymore. So, we need to check for change in master
+            if (event.localNodeClusterManager()) {
+                // We don't remove old cluster-manager when cluster-manager flips anymore. So, we need to check for change in
+                // cluster-manager
                 SnapshotsInProgress snapshotsInProgress = event.state().custom(SnapshotsInProgress.TYPE, SnapshotsInProgress.EMPTY);
-                final boolean newMaster = event.previousState().nodes().isLocalNodeElectedMaster() == false;
+                final boolean newClusterManager = event.previousState().nodes().isLocalNodeElectedClusterManager() == false;
                 processExternalChanges(
-                    newMaster || removedNodesCleanupNeeded(snapshotsInProgress, event.nodesDelta().removedNodes()),
+                    newClusterManager || removedNodesCleanupNeeded(snapshotsInProgress, event.nodesDelta().removedNodes()),
                     event.routingTableChanged() && waitingShardsStartedOrUnassigned(snapshotsInProgress, event)
                 );
             } else if (snapshotCompletionListeners.isEmpty() == false) {
-                // We have snapshot listeners but are not the master any more. Fail all waiting listeners except for those that already
+                // We have snapshot listeners but are not the cluster-manager any more. Fail all waiting listeners except for those that
+                // already
                 // have their snapshots finalizing (those that are already finalizing will fail on their own from to update the cluster
                 // state).
                 for (Snapshot snapshot : new HashSet<>(snapshotCompletionListeners.keySet())) {
                     if (endingSnapshots.add(snapshot)) {
-                        failSnapshotCompletionListeners(snapshot, new SnapshotException(snapshot, "no longer master"));
+                        failSnapshotCompletionListeners(snapshot, new SnapshotException(snapshot, "no longer cluster-manager"));
                     }
                 }
             }
@@ -1326,7 +1417,7 @@ public void applyClusterState(ClusterChangedEvent event) {
     /**
      * Cleanup all snapshots found in the given cluster state that have no more work left:
      * 1. Completed snapshots
-     * 2. Snapshots in state INIT that a previous master of an older version failed to start
+     * 2. Snapshots in state INIT that a previous cluster-manager of an older version failed to start
      * 3. Snapshots in any other state that have all their shard tasks completed
      */
     private void endCompletedSnapshots(ClusterState state) {
@@ -1389,8 +1480,8 @@ private static boolean assertNoDanglingSnapshots(ClusterState state) {
         final Set<String> reposSeen = new HashSet<>();
         for (SnapshotsInProgress.Entry entry : snapshotsInProgress.entries()) {
             if (reposSeen.add(entry.repository())) {
-                for (ObjectCursor<ShardSnapshotStatus> value : entry.shards().values()) {
-                    if (value.value.equals(ShardSnapshotStatus.UNASSIGNED_QUEUED)) {
+                for (final ShardSnapshotStatus status : entry.shards().values()) {
+                    if (status.equals(ShardSnapshotStatus.UNASSIGNED_QUEUED)) {
                         assert reposWithRunningDelete.contains(entry.repository()) : "Found shard snapshot waiting to be assigned in ["
                             + entry
                             + "] but it is not blocked by any running delete";
@@ -1402,11 +1493,11 @@ private static boolean assertNoDanglingSnapshots(ClusterState state) {
     }
 
     /**
-     * Updates the state of in-progress snapshots in reaction to a change in the configuration of the cluster nodes (master fail-over or
+     * Updates the state of in-progress snapshots in reaction to a change in the configuration of the cluster nodes (cluster-manager fail-over or
      * disconnect of a data node that was executing a snapshot) or a routing change that started shards whose snapshot state is
      * {@link SnapshotsInProgress.ShardState#WAITING}.
      *
-     * @param changedNodes true iff either a master fail-over occurred or a data node that was doing snapshot work got removed from the
+     * @param changedNodes true iff either a cluster-manager fail-over occurred or a data node that was doing snapshot work got removed from the
      *                     cluster
      * @param startShards  true iff any waiting shards were started due to a routing change
      */
@@ -1459,7 +1550,7 @@ public ClusterState execute(ClusterState currentState) {
                                     changed = true;
                                 }
                             } else {
-                                ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards = processWaitingShardsAndRemovedNodes(
+                                final Map<ShardId, ShardSnapshotStatus> shards = processWaitingShardsAndRemovedNodes(
                                     snapshot.shards(),
                                     routingTable,
                                     nodes,
@@ -1554,17 +1645,17 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         );
     }
 
-    private static ImmutableOpenMap<ShardId, ShardSnapshotStatus> processWaitingShardsAndRemovedNodes(
-        ImmutableOpenMap<ShardId, ShardSnapshotStatus> snapshotShards,
+    private static Map<ShardId, ShardSnapshotStatus> processWaitingShardsAndRemovedNodes(
+        final Map<ShardId, ShardSnapshotStatus> snapshotShards,
         RoutingTable routingTable,
         DiscoveryNodes nodes,
         Map<ShardId, ShardSnapshotStatus> knownFailures
     ) {
         boolean snapshotChanged = false;
-        ImmutableOpenMap.Builder<ShardId, ShardSnapshotStatus> shards = ImmutableOpenMap.builder();
-        for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardEntry : snapshotShards) {
-            ShardSnapshotStatus shardStatus = shardEntry.value;
-            ShardId shardId = shardEntry.key;
+        final Map<ShardId, ShardSnapshotStatus> shards = new HashMap<>();
+        for (final Map.Entry<ShardId, ShardSnapshotStatus> shardEntry : snapshotShards.entrySet()) {
+            ShardSnapshotStatus shardStatus = shardEntry.getValue();
+            ShardId shardId = shardEntry.getKey();
             if (shardStatus.equals(ShardSnapshotStatus.UNASSIGNED_QUEUED)) {
                 // this shard snapshot is waiting for a previous snapshot to finish execution for this shard
                 final ShardSnapshotStatus knownFailure = knownFailures.get(shardId);
@@ -1630,7 +1721,7 @@ private static ImmutableOpenMap<ShardId, ShardSnapshotStatus> processWaitingShar
             }
         }
         if (snapshotChanged) {
-            return shards.build();
+            return Collections.unmodifiableMap(shards);
         } else {
             return null;
         }
@@ -1639,11 +1730,11 @@ private static ImmutableOpenMap<ShardId, ShardSnapshotStatus> processWaitingShar
     private static boolean waitingShardsStartedOrUnassigned(SnapshotsInProgress snapshotsInProgress, ClusterChangedEvent event) {
         for (SnapshotsInProgress.Entry entry : snapshotsInProgress.entries()) {
             if (entry.state() == State.STARTED) {
-                for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardStatus : entry.shards()) {
-                    if (shardStatus.value.state() != ShardState.WAITING) {
+                for (final Map.Entry<ShardId, ShardSnapshotStatus> shardStatus : entry.shards().entrySet()) {
+                    if (shardStatus.getValue().state() != ShardState.WAITING) {
                         continue;
                     }
-                    final ShardId shardId = shardStatus.key;
+                    final ShardId shardId = shardStatus.getKey();
                     if (event.indexRoutingTableChanged(shardId.getIndexName())) {
                         IndexRoutingTable indexShardRoutingTable = event.state().getRoutingTable().index(shardId.getIndex());
                         if (indexShardRoutingTable == null) {
@@ -1672,8 +1763,7 @@ private static boolean removedNodesCleanupNeeded(SnapshotsInProgress snapshotsIn
                 // nothing to do for already completed snapshots
                 return false;
             }
-            for (ObjectCursor<ShardSnapshotStatus> shardStatus : snapshot.shards().values()) {
-                final ShardSnapshotStatus shardSnapshotStatus = shardStatus.value;
+            for (final ShardSnapshotStatus shardSnapshotStatus : snapshot.shards().values()) {
                 if (shardSnapshotStatus.state().completed() == false && removedNodeIds.contains(shardSnapshotStatus.nodeId())) {
                     // Snapshot had an incomplete shard running on a removed node so we need to adjust that shard's snapshot status
                     return true;
@@ -1690,18 +1780,18 @@ private static boolean removedNodesCleanupNeeded(SnapshotsInProgress snapshotsIn
      * @return list of failed and closed indices
      */
     private static Tuple<Set<String>, Set<String>> indicesWithMissingShards(
-        ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards,
+        final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards,
         Metadata metadata
     ) {
         Set<String> missing = new HashSet<>();
         Set<String> closed = new HashSet<>();
-        for (ObjectObjectCursor<ShardId, SnapshotsInProgress.ShardSnapshotStatus> entry : shards) {
-            if (entry.value.state() == ShardState.MISSING) {
-                if (metadata.hasIndex(entry.key.getIndex().getName())
-                    && metadata.getIndexSafe(entry.key.getIndex()).getState() == IndexMetadata.State.CLOSE) {
-                    closed.add(entry.key.getIndex().getName());
+        for (final Map.Entry<ShardId, SnapshotsInProgress.ShardSnapshotStatus> entry : shards.entrySet()) {
+            if (entry.getValue().state() == ShardState.MISSING) {
+                if (metadata.hasIndex(entry.getKey().getIndex().getName())
+                    && metadata.getIndexSafe(entry.getKey().getIndex()).getState() == IndexMetadata.State.CLOSE) {
+                    closed.add(entry.getKey().getIndex().getName());
                 } else {
-                    missing.add(entry.key.getIndex().getName());
+                    missing.add(entry.getKey().getIndex().getName());
                 }
             }
         }
@@ -1789,9 +1879,9 @@ private void finalizeSnapshotEntry(SnapshotsInProgress.Entry entry, Metadata met
             final Snapshot snapshot = entry.snapshot();
             logger.trace("[{}] finalizing snapshot in repository, state: [{}], failure[{}]", snapshot, entry.state(), failure);
             ArrayList<SnapshotShardFailure> shardFailures = new ArrayList<>();
-            for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> shardStatus : entry.shards()) {
-                ShardId shardId = shardStatus.key;
-                ShardSnapshotStatus status = shardStatus.value;
+            for (final Map.Entry<ShardId, ShardSnapshotStatus> shardStatus : entry.shards().entrySet()) {
+                ShardId shardId = shardStatus.getKey();
+                ShardSnapshotStatus status = shardStatus.getValue();
                 final ShardState state = status.state();
                 if (state.failed()) {
                     shardFailures.add(new SnapshotShardFailure(status.nodeId(), shardId, status.reason()));
@@ -1813,7 +1903,8 @@ private void finalizeSnapshotEntry(SnapshotsInProgress.Entry entry, Metadata met
                 entry.partial() ? shardGenerations.totalShards() : entry.shards().size(),
                 shardFailures,
                 entry.includeGlobalState(),
-                entry.userMetadata()
+                entry.userMetadata(),
+                entry.remoteStoreIndexShallowCopy()
             );
             final StepListener<Metadata> metadataListener = new StepListener<>();
             final Repository repo = repositoriesService.repository(snapshot.getRepository());
@@ -1863,7 +1954,7 @@ private List<ActionListener<Tuple<RepositoryData, SnapshotInfo>>> endAndGetListe
 
     /**
      * Handles failure to finalize a snapshot. If the exception indicates that this node was unable to publish a cluster state and stopped
-     * being the master node, then fail all snapshot create and delete listeners executing on this node by delegating to
+     * being the cluster-manager node, then fail all snapshot create and delete listeners executing on this node by delegating to
      * {@link #failAllListenersOnMasterFailOver}. Otherwise, i.e. as a result of failing to write to the snapshot repository for some
      * reason, remove the snapshot's {@link SnapshotsInProgress.Entry} from the cluster state and move on with other queued snapshot
      * operations if there are any.
@@ -1874,8 +1965,8 @@ private List<ActionListener<Tuple<RepositoryData, SnapshotInfo>>> endAndGetListe
      */
     private void handleFinalizationFailure(Exception e, SnapshotsInProgress.Entry entry, RepositoryData repositoryData) {
         Snapshot snapshot = entry.snapshot();
-        if (ExceptionsHelper.unwrap(e, NotMasterException.class, FailedToCommitClusterStateException.class) != null) {
-            // Failure due to not being master any more, don't try to remove snapshot from cluster state the next master
+        if (ExceptionsHelper.unwrap(e, NotClusterManagerException.class, FailedToCommitClusterStateException.class) != null) {
+            // Failure due to not being cluster-manager any more, don't try to remove snapshot from cluster state the next cluster-manager
             // will try ending this snapshot again
             logger.debug(() -> new ParameterizedMessage("[{}] failed to update cluster state during snapshot finalization", snapshot), e);
             failSnapshotCompletionListeners(
@@ -2081,12 +2172,12 @@ public void onFailure(String source, Exception e) {
             }
 
             @Override
-            public void onNoLongerMaster(String source) {
-                failure.addSuppressed(new SnapshotException(snapshot, "no longer master"));
+            public void onNoLongerClusterManager(String source) {
+                failure.addSuppressed(new SnapshotException(snapshot, "no longer cluster-manager"));
                 failSnapshotCompletionListeners(snapshot, failure);
-                failAllListenersOnMasterFailOver(new NotMasterException(source));
+                failAllListenersOnMasterFailOver(new NotClusterManagerException(source));
                 if (listener != null) {
-                    listener.onNoLongerMaster();
+                    listener.onNoLongerClusterManager();
                 }
             }
 
@@ -2191,6 +2282,7 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                     snapshotNames,
                     repoName
                 );
+                validateSnapshotsBackingAnyIndex(currentState.getMetadata().getIndices(), snapshotIds, repoName);
                 if (snapshotEntries.isEmpty() || minNodeVersion.onOrAfter(SnapshotsService.FULL_CONCURRENCY_VERSION)) {
                     deleteFromRepoTask = createDeleteStateUpdate(snapshotIds, repoName, repositoryData, Priority.NORMAL, listener);
                     return deleteFromRepoTask.execute(currentState);
@@ -2198,7 +2290,7 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                 assert snapshotEntries.size() == 1 : "Expected just a single running snapshot but saw " + snapshotEntries;
                 final SnapshotsInProgress.Entry snapshotEntry = snapshotEntries.get(0);
                 runningSnapshot = snapshotEntry.snapshot();
-                final ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards;
+                final Map<ShardId, ShardSnapshotStatus> shards;
 
                 final State state = snapshotEntry.state();
                 final String failure;
@@ -2222,11 +2314,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                 } else {
                     boolean hasUncompletedShards = false;
                     // Cleanup in case a node gone missing and snapshot wasn't updated for some reason
-                    for (ObjectCursor<ShardSnapshotStatus> shardStatus : snapshotEntry.shards().values()) {
+                    for (final ShardSnapshotStatus shardStatus : snapshotEntry.shards().values()) {
                         // Check if we still have shard running on existing nodes
-                        if (shardStatus.value.state().completed() == false
-                            && shardStatus.value.nodeId() != null
-                            && currentState.nodes().get(shardStatus.value.nodeId()) != null) {
+                        if (shardStatus.state().completed() == false
+                            && shardStatus.nodeId() != null
+                            && currentState.nodes().get(shardStatus.nodeId()) != null) {
                             hasUncompletedShards = true;
                             break;
                         }
@@ -2249,7 +2341,7 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                         SnapshotsInProgress.of(
                             snapshots.entries()
                                 .stream()
-                                // remove init state snapshot we found from a previous master if there was one
+                                // remove init state snapshot we found from a previous cluster-manager if there was one
                                 .filter(existing -> abortedDuringInit == false || existing.equals(snapshotEntry) == false)
                                 .map(existing -> {
                                     if (existing.equals(snapshotEntry)) {
@@ -2263,6 +2355,11 @@ public ClusterState execute(ClusterState currentState) throws Exception {
                     .build();
             }
 
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return deleteSnapshotTaskKey;
+            }
+
             @Override
             public void onFailure(String source, Exception e) {
                 listener.onFailure(e);
@@ -2296,9 +2393,9 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                         createDeleteStateUpdate(outstandingDeletes, repoName, result.v1(), Priority.IMMEDIATE, listener)
                     );
                 }, e -> {
-                    if (ExceptionsHelper.unwrap(e, NotMasterException.class, FailedToCommitClusterStateException.class) != null) {
-                        logger.warn("master failover before deleted snapshot could complete", e);
-                        // Just pass the exception to the transport handler as is so it is retried on the new master
+                    if (ExceptionsHelper.unwrap(e, NotClusterManagerException.class, FailedToCommitClusterStateException.class) != null) {
+                        logger.warn("cluster-manager failover before deleted snapshot could complete", e);
+                        // Just pass the exception to the transport handler as is so it is retried on the new cluster-manager
                         listener.onFailure(e);
                     } else {
                         logger.warn("deleted snapshot failed", e);
@@ -2311,7 +2408,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
 
             @Override
             public TimeValue timeout() {
-                return request.masterNodeTimeout();
+                return request.clusterManagerNodeTimeout();
             }
         }, "delete snapshot", listener::onFailure);
     }
@@ -2588,11 +2685,11 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
      */
     private static boolean isWritingToRepository(SnapshotsInProgress.Entry entry) {
         if (entry.state().completed()) {
-            // Entry is writing to the repo because it's finalizing on master
+            // Entry is writing to the repo because it's finalizing on cluster-manager
             return true;
         }
-        for (ObjectCursor<ShardSnapshotStatus> value : entry.shards().values()) {
-            if (value.value.isActive()) {
+        for (final ShardSnapshotStatus value : entry.shards().values()) {
+            if (value.isActive()) {
                 // Entry is writing to the repo because it's writing to a shard on a data node or waiting to do so for a concrete shard
                 return true;
             }
@@ -2701,8 +2798,27 @@ private void deleteSnapshotsFromRepository(
             assert currentlyFinalizing.contains(deleteEntry.repository());
             final List<SnapshotId> snapshotIds = deleteEntry.getSnapshots();
             assert deleteEntry.state() == SnapshotDeletionsInProgress.State.STARTED : "incorrect state for entry [" + deleteEntry + "]";
-            repositoriesService.repository(deleteEntry.repository())
-                .deleteSnapshots(
+            final Repository repository = repositoriesService.repository(deleteEntry.repository());
+
+            // TODO: Relying on repository flag to decide delete flow may lead to shallow snapshot blobs not being taken up for cleanup
+            // when the repository currently have the flag disabled and we try to delete the shallow snapshots taken prior to disabling
+            // the flag. This can be improved by having the info whether there ever were any shallow snapshot present in this repository
+            // or not in RepositoryData.
+            // SEE https://github.com/opensearch-project/OpenSearch/issues/8610
+            final boolean cleanupRemoteStoreLockFiles = REMOTE_STORE_INDEX_SHALLOW_COPY.get(repository.getMetadata().settings());
+            if (cleanupRemoteStoreLockFiles) {
+                repository.deleteSnapshotsAndReleaseLockFiles(
+                    snapshotIds,
+                    repositoryData.getGenId(),
+                    minCompatibleVersion(minNodeVersion, repositoryData, snapshotIds),
+                    remoteStoreLockManagerFactory,
+                    ActionListener.wrap(updatedRepoData -> {
+                        logger.info("snapshots {} deleted", snapshotIds);
+                        removeSnapshotDeletionFromClusterState(deleteEntry, null, updatedRepoData);
+                    }, ex -> removeSnapshotDeletionFromClusterState(deleteEntry, ex, repositoryData))
+                );
+            } else {
+                repository.deleteSnapshots(
                     snapshotIds,
                     repositoryData.getGenId(),
                     minCompatibleVersion(minNodeVersion, repositoryData, snapshotIds),
@@ -2711,6 +2827,7 @@ private void deleteSnapshotsFromRepository(
                         removeSnapshotDeletionFromClusterState(deleteEntry, null, updatedRepoData);
                     }, ex -> removeSnapshotDeletionFromClusterState(deleteEntry, ex, repositoryData))
                 );
+            }
         }
     }
 
@@ -2769,19 +2886,19 @@ protected void handleListeners(List<ActionListener<Void>> deleteListeners) {
     }
 
     /**
-     * Handle snapshot or delete failure due to not being master any more so we don't try to do run additional cluster state updates.
-     * The next master will try handling the missing operations. All we can do is fail all the listeners on this master node so that
+     * Handle snapshot or delete failure due to not being cluster-manager any more so we don't try to do run additional cluster state updates.
+     * The next cluster-manager will try handling the missing operations. All we can do is fail all the listeners on this cluster-manager node so that
      * transport requests return and we don't leak listeners.
      *
-     * @param e exception that caused us to realize we are not master any longer
+     * @param e exception that caused us to realize we are not cluster-manager any longer
      */
     private void failAllListenersOnMasterFailOver(Exception e) {
-        logger.debug("Failing all snapshot operation listeners because this node is not master any longer", e);
+        logger.debug("Failing all snapshot operation listeners because this node is not cluster-manager any longer", e);
         synchronized (currentlyFinalizing) {
-            if (ExceptionsHelper.unwrap(e, NotMasterException.class, FailedToCommitClusterStateException.class) != null) {
+            if (ExceptionsHelper.unwrap(e, NotClusterManagerException.class, FailedToCommitClusterStateException.class) != null) {
                 repositoryOperations.clear();
                 for (Snapshot snapshot : new HashSet<>(snapshotCompletionListeners.keySet())) {
-                    failSnapshotCompletionListeners(snapshot, new SnapshotException(snapshot, "no longer master"));
+                    failSnapshotCompletionListeners(snapshot, new SnapshotException(snapshot, "no longer cluster-manager"));
                 }
                 final Exception wrapped = new RepositoryException("_all", "Failed to update cluster state during repository operation", e);
                 for (Iterator<List<ActionListener<Void>>> iterator = snapshotDeletionListeners.values().iterator(); iterator.hasNext();) {
@@ -2911,16 +3028,16 @@ private SnapshotsInProgress updatedSnapshotsInProgress(ClusterState currentState
 
             final String repoName = deleteEntry.repository();
             // Computing the new assignments can be quite costly, only do it once below if actually needed
-            ImmutableOpenMap<ShardId, ShardSnapshotStatus> shardAssignments = null;
+            Map<ShardId, ShardSnapshotStatus> shardAssignments = null;
             for (SnapshotsInProgress.Entry entry : snapshotsInProgress.entries()) {
                 if (entry.repository().equals(repoName)) {
                     if (entry.state().completed() == false) {
                         // Collect waiting shards that in entry that we can assign now that we are done with the deletion
                         final List<ShardId> canBeUpdated = new ArrayList<>();
-                        for (ObjectObjectCursor<ShardId, ShardSnapshotStatus> value : entry.shards()) {
-                            if (value.value.equals(ShardSnapshotStatus.UNASSIGNED_QUEUED)
-                                && reassignedShardIds.contains(value.key) == false) {
-                                canBeUpdated.add(value.key);
+                        for (final Map.Entry<ShardId, ShardSnapshotStatus> value : entry.shards().entrySet()) {
+                            if (value.getValue().equals(ShardSnapshotStatus.UNASSIGNED_QUEUED)
+                                && reassignedShardIds.contains(value.getKey()) == false) {
+                                canBeUpdated.add(value.getKey());
                             }
                         }
                         if (canBeUpdated.isEmpty()) {
@@ -2939,8 +3056,7 @@ private SnapshotsInProgress updatedSnapshotsInProgress(ClusterState currentState
                                     repoName
                                 );
                             }
-                            final ImmutableOpenMap.Builder<ShardId, ShardSnapshotStatus> updatedAssignmentsBuilder = ImmutableOpenMap
-                                .builder(entry.shards());
+                            final Map<ShardId, ShardSnapshotStatus> updatedAssignmentsBuilder = new HashMap<>(entry.shards());
                             for (ShardId shardId : canBeUpdated) {
                                 final ShardSnapshotStatus updated = shardAssignments.get(shardId);
                                 if (updated == null) {
@@ -2955,8 +3071,14 @@ private SnapshotsInProgress updatedSnapshotsInProgress(ClusterState currentState
                                     updatedAssignmentsBuilder.put(shardId, updated);
                                 }
                             }
-                            snapshotEntries.add(entry.withStartedShards(updatedAssignmentsBuilder.build()));
+                            final SnapshotsInProgress.Entry updatedEntry = entry.withShardStates(updatedAssignmentsBuilder);
+                            snapshotEntries.add(updatedEntry);
                             changed = true;
+                            // When all the required shards for a snapshot are missing, the snapshot state will be "completed"
+                            // need to finalize it.
+                            if (updatedEntry.state().completed()) {
+                                newFinalizations.add(entry);
+                            }
                         }
                     } else {
                         // Entry is already completed so we will finalize it now that the delete doesn't block us after
@@ -3030,7 +3152,7 @@ private static <T> void completeListenersIgnoringException(@Nullable List<Action
      * @param useShardGenerations whether to write {@link ShardGenerations} during the snapshot
      * @return list of shard to be included into current snapshot
      */
-    private static ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards(
+    private static Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards(
         SnapshotsInProgress snapshotsInProgress,
         @Nullable SnapshotDeletionsInProgress deletionsInProgress,
         Metadata metadata,
@@ -3040,7 +3162,7 @@ private static ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus
         RepositoryData repositoryData,
         String repoName
     ) {
-        ImmutableOpenMap.Builder<ShardId, SnapshotsInProgress.ShardSnapshotStatus> builder = ImmutableOpenMap.builder();
+        final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> builder = new HashMap<>();
         final ShardGenerations shardGenerations = repositoryData.shardGenerations();
         final InFlightShardSnapshotStates inFlightShardStates = InFlightShardSnapshotStates.forRepo(
             repoName,
@@ -3112,7 +3234,7 @@ private static ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus
             }
         }
 
-        return builder.build();
+        return Collections.unmodifiableMap(builder);
     }
 
     /**
@@ -3213,7 +3335,7 @@ public boolean assertAllListenersResolved() {
      *
      * If the inner loop finds that a shard update task applies to a given snapshot and either a shard-snapshot or shard-clone operation in
      * it then it will update the state of the snapshot entry accordingly. If that update was a noop, then the task is removed from the
-     * iteration as it was already applied before and likely just arrived on the master node again due to retries upstream.
+     * iteration as it was already applied before and likely just arrived on the cluster-manager node again due to retries upstream.
      * If the update was not a noop, then it means that the shard it applied to is now available for another snapshot or clone operation
      * to be re-assigned if there is another snapshot operation that is waiting for the shard to become available. We therefore record the
      * fact that a task was executed by adding it to a collection of executed tasks. If a subsequent execution of the outer loop finds that
@@ -3223,7 +3345,20 @@ public boolean assertAllListenersResolved() {
      *
      * Package private to allow for tests.
      */
-    static final ClusterStateTaskExecutor<ShardSnapshotUpdate> SHARD_STATE_EXECUTOR = (currentState, tasks) -> {
+    static final ClusterStateTaskExecutor<ShardSnapshotUpdate> SHARD_STATE_EXECUTOR = new ClusterStateTaskExecutor<ShardSnapshotUpdate>() {
+        @Override
+        public ClusterTasksResult<ShardSnapshotUpdate> execute(ClusterState currentState, List<ShardSnapshotUpdate> tasks)
+            throws Exception {
+            return shardStateExecutor.execute(currentState, tasks);
+        }
+
+        @Override
+        public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+            return updateSnapshotStateTaskKey;
+        }
+    };
+
+    static final ClusterStateTaskExecutor<ShardSnapshotUpdate> shardStateExecutor = (currentState, tasks) -> {
         int changedCount = 0;
         int startedCount = 0;
         final List<SnapshotsInProgress.Entry> entries = new ArrayList<>();
@@ -3239,8 +3374,8 @@ public boolean assertAllListenersResolved() {
                 entries.add(entry);
                 continue;
             }
-            ImmutableOpenMap.Builder<ShardId, ShardSnapshotStatus> shards = null;
-            ImmutableOpenMap.Builder<RepositoryShardId, ShardSnapshotStatus> clones = null;
+            Map<ShardId, ShardSnapshotStatus> shards = null;
+            Map<RepositoryShardId, ShardSnapshotStatus> clones = null;
             Map<String, IndexId> indicesLookup = null;
             // inner loop over all the shard updates that are potentially applicable to the current snapshot entry
             for (Iterator<ShardSnapshotUpdate> iterator = unconsumedTasks.iterator(); iterator.hasNext();) {
@@ -3267,7 +3402,8 @@ public boolean assertAllListenersResolved() {
                                 updateSnapshotState,
                                 entry
                             );
-                            assert false : "This should never happen, master will not submit a state update for a non-existing clone";
+                            assert false
+                                : "This should never happen, cluster-manager will not submit a state update for a non-existing clone";
                             continue;
                         }
                         if (existing.state().completed()) {
@@ -3282,7 +3418,7 @@ public boolean assertAllListenersResolved() {
                             updateSnapshotState.updatedState.state()
                         );
                         if (clones == null) {
-                            clones = ImmutableOpenMap.builder(entry.clones());
+                            clones = new HashMap<>(entry.clones());
                         }
                         changedCount++;
                         clones.put(finishedShardId, updateSnapshotState.updatedState);
@@ -3297,7 +3433,7 @@ public boolean assertAllListenersResolved() {
                                 continue;
                             }
                             if (clones == null) {
-                                clones = ImmutableOpenMap.builder(entry.clones());
+                                clones = new HashMap<>(entry.clones());
                             }
                             final ShardSnapshotStatus finishedStatus = updateSnapshotState.updatedState;
                             logger.trace(
@@ -3327,7 +3463,7 @@ public boolean assertAllListenersResolved() {
                                 continue;
                             }
                             if (shards == null) {
-                                shards = ImmutableOpenMap.builder(entry.shards());
+                                shards = new HashMap<>(entry.shards());
                             }
                             final ShardSnapshotStatus finishedStatus = updateSnapshotState.updatedState;
                             logger.trace(
@@ -3377,7 +3513,7 @@ public boolean assertAllListenersResolved() {
                             updateSnapshotState.updatedState.state()
                         );
                         if (shards == null) {
-                            shards = ImmutableOpenMap.builder(entry.shards());
+                            shards = new HashMap(entry.shards());
                         }
                         shards.put(finishedShardId, updateSnapshotState.updatedState);
                         executedTasks.add(updateSnapshotState);
@@ -3402,7 +3538,7 @@ public boolean assertAllListenersResolved() {
                                     continue;
                                 }
                                 if (clones == null) {
-                                    clones = ImmutableOpenMap.builder(entry.clones());
+                                    clones = new HashMap<>(entry.clones());
                                 }
                                 final ShardSnapshotStatus finishedStatus = updateSnapshotState.updatedState;
                                 logger.trace(
@@ -3422,7 +3558,7 @@ public boolean assertAllListenersResolved() {
                                 continue;
                             }
                             if (shards == null) {
-                                shards = ImmutableOpenMap.builder(entry.shards());
+                                shards = new HashMap<>(entry.shards());
                             }
                             final ShardSnapshotStatus finishedStatus = updateSnapshotState.updatedState;
                             logger.trace(
@@ -3444,9 +3580,9 @@ public boolean assertAllListenersResolved() {
                     + clones
                     + " as well as "
                     + shards;
-                updatedEntry = entry.withShardStates(shards.build());
+                updatedEntry = entry.withShardStates(shards);
             } else if (clones != null) {
-                updatedEntry = entry.withClones(clones.build());
+                updatedEntry = entry.withClones(clones);
             } else {
                 updatedEntry = entry;
             }
@@ -3595,14 +3731,16 @@ private void startExecutableClones(SnapshotsInProgress snapshotsInProgress, @Nul
         for (SnapshotsInProgress.Entry entry : snapshotsInProgress.entries()) {
             if (entry.isClone() && entry.state() == State.STARTED && (repoName == null || entry.repository().equals(repoName))) {
                 // this is a clone, see if new work is ready
-                for (ObjectObjectCursor<RepositoryShardId, ShardSnapshotStatus> clone : entry.clones()) {
-                    if (clone.value.state() == ShardState.INIT) {
+                for (final Map.Entry<RepositoryShardId, ShardSnapshotStatus> clone : entry.clones().entrySet()) {
+                    if (clone.getValue().state() == ShardState.INIT) {
+                        final boolean remoteStoreIndexShallowCopy = Boolean.TRUE.equals(entry.remoteStoreIndexShallowCopy());
                         runReadyClone(
                             entry.snapshot(),
                             entry.source(),
-                            clone.value,
-                            clone.key,
-                            repositoriesService.repository(entry.repository())
+                            clone.getValue(),
+                            clone.getKey(),
+                            repositoriesService.repository(entry.repository()),
+                            remoteStoreIndexShallowCopy
                         );
                     }
                 }
@@ -3610,7 +3748,7 @@ private void startExecutableClones(SnapshotsInProgress snapshotsInProgress, @Nul
         }
     }
 
-    private class UpdateSnapshotStatusAction extends TransportMasterNodeAction<
+    private class UpdateSnapshotStatusAction extends TransportClusterManagerNodeAction<
         UpdateIndexShardSnapshotStatusRequest,
         UpdateIndexShardSnapshotStatusResponse> {
         UpdateSnapshotStatusAction(
@@ -3643,7 +3781,7 @@ protected UpdateIndexShardSnapshotStatusResponse read(StreamInput in) throws IOE
         }
 
         @Override
-        protected void masterOperation(
+        protected void clusterManagerOperation(
             UpdateIndexShardSnapshotStatusRequest request,
             ClusterState state,
             ActionListener<UpdateIndexShardSnapshotStatusResponse> listener
@@ -3810,8 +3948,8 @@ synchronized void addFinalization(SnapshotsInProgress.Entry entry, Metadata meta
         }
 
         /**
-         * Clear all state associated with running snapshots. To be used on master-failover if the current node stops
-         * being master.
+         * Clear all state associated with running snapshots. To be used on cluster-manager-failover if the current node stops
+         * being cluster-manager.
          */
         synchronized void clear() {
             snapshotsToFinalize.clear();
diff --git a/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusRequest.java b/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusRequest.java
index f4f629970ccfa..6ae1e0d45cb6e 100644
--- a/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusRequest.java
+++ b/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusRequest.java
@@ -32,20 +32,22 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.support.master.MasterNodeRequest;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.cluster.SnapshotsInProgress;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.io.IOException;
 import java.util.Objects;
 
 /**
  * Internal request that is used to send changes in snapshot status to master
+ *
+ * @opensearch.internal
  */
-public class UpdateIndexShardSnapshotStatusRequest extends MasterNodeRequest<UpdateIndexShardSnapshotStatusRequest> {
+public class UpdateIndexShardSnapshotStatusRequest extends ClusterManagerNodeRequest<UpdateIndexShardSnapshotStatusRequest> {
     private final Snapshot snapshot;
     private final ShardId shardId;
     private final SnapshotsInProgress.ShardSnapshotStatus status;
@@ -62,7 +64,7 @@ public UpdateIndexShardSnapshotStatusRequest(Snapshot snapshot, ShardId shardId,
         this.shardId = shardId;
         this.status = status;
         // By default, we keep trying to post snapshot status messages to avoid snapshot processes getting stuck.
-        this.masterNodeTimeout = TimeValue.timeValueNanos(Long.MAX_VALUE);
+        this.clusterManagerNodeTimeout = TimeValue.timeValueNanos(Long.MAX_VALUE);
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusResponse.java b/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusResponse.java
index 55b299c7832c8..6bcbc932f3eff 100644
--- a/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusResponse.java
+++ b/server/src/main/java/org/opensearch/snapshots/UpdateIndexShardSnapshotStatusResponse.java
@@ -31,11 +31,16 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Response sent when updating an index shard status
+ *
+ * @opensearch.internal
+ */
 class UpdateIndexShardSnapshotStatusResponse extends ActionResponse {
 
     public static final UpdateIndexShardSnapshotStatusResponse INSTANCE = new UpdateIndexShardSnapshotStatusResponse();
diff --git a/server/src/main/java/org/opensearch/snapshots/package-info.java b/server/src/main/java/org/opensearch/snapshots/package-info.java
index 82d7a0d88ff00..a573d7a136620 100644
--- a/server/src/main/java/org/opensearch/snapshots/package-info.java
+++ b/server/src/main/java/org/opensearch/snapshots/package-info.java
@@ -30,13 +30,13 @@
  *
  * <h2>Preliminaries</h2>
  *
- * <p>There are two communication channels between all nodes and master in the snapshot functionality:</p>
+ * <p>There are two communication channels between all nodes and cluster-manager in the snapshot functionality:</p>
  * <ul>
- * <li>The master updates the cluster state by adding, removing or altering the contents of its custom entry
+ * <li>The cluster-manager updates the cluster state by adding, removing or altering the contents of its custom entry
  * {@link org.opensearch.cluster.SnapshotsInProgress}. All nodes consume the state of the {@code SnapshotsInProgress} and will start or
  * abort relevant shard snapshot tasks accordingly.</li>
  * <li>Nodes that are executing shard snapshot tasks report either success or failure of their snapshot task by submitting a
- * {@link org.opensearch.snapshots.UpdateIndexShardSnapshotStatusRequest} to the master node that will update the
+ * {@link org.opensearch.snapshots.UpdateIndexShardSnapshotStatusRequest} to the cluster-manager node that will update the
  * snapshot's entry in the cluster state accordingly.</li>
  * </ul>
  *
@@ -45,7 +45,7 @@
  * <ol>
  * <li>First the {@link org.opensearch.snapshots.SnapshotsService} determines the primary shards' assignments for all indices that are
  * being snapshotted and creates a {@code SnapshotsInProgress.Entry} with state {@code STARTED} and adds the map of
- * {@link org.opensearch.index.shard.ShardId} to {@link org.opensearch.cluster.SnapshotsInProgress.ShardSnapshotStatus} that tracks
+ * {@link org.opensearch.core.index.shard.ShardId} to {@link org.opensearch.cluster.SnapshotsInProgress.ShardSnapshotStatus} that tracks
  * the assignment of which node is to snapshot which shard. All shard snapshots are executed on the shard's primary node. Thus all shards
  * for which the primary node was found to have a healthy copy of the shard are marked as being in state {@code INIT} in this map. If the
  * primary for a shard is unassigned, it is marked as {@code MISSING} in this map. In case the primary is initializing at this point, it is
@@ -57,8 +57,8 @@
  * the {@code SnapshotShardsService} will check if any local primary shards are to be snapshotted (signaled by the shard's snapshot state
  * being {@code INIT}). For those local primary shards found in state {@code INIT}) the snapshot process of writing the shard's data files
  * to the snapshot's {@link org.opensearch.repositories.Repository} is executed. Once the snapshot execution finishes for a shard an
- * {@code UpdateIndexShardSnapshotStatusRequest} is sent to the master node signaling either status {@code SUCCESS} or {@code FAILED}.
- * The master node will then update a shard's state in the snapshots {@code SnapshotsInProgress.Entry} whenever it receives such a
+ * {@code UpdateIndexShardSnapshotStatusRequest} is sent to the cluster-manager node signaling either status {@code SUCCESS} or {@code FAILED}.
+ * The cluster-manager node will then update a shard's state in the snapshots {@code SnapshotsInProgress.Entry} whenever it receives such a
  * {@code UpdateIndexShardSnapshotStatusRequest}.</li>
  *
  * <li>If as a result of the received status update requests, all shards in the cluster state are in a completed state, i.e are marked as
@@ -82,12 +82,12 @@
  * <li>Aborting a snapshot starts by updating the state of the snapshot's {@code SnapshotsInProgress.Entry} to {@code ABORTED}.</li>
  *
  * <li>The snapshot's state change to {@code ABORTED} in cluster state is then picked up by the {@code SnapshotShardsService} on all nodes.
- * Those nodes that have shard snapshot actions for the snapshot assigned to them, will abort them and notify master about the shards
+ * Those nodes that have shard snapshot actions for the snapshot assigned to them, will abort them and notify cluster-manager about the shards
  * snapshot status accordingly. If the shard snapshot action completed or was in state {@code FINALIZE} when the abort was registered by
- * the {@code SnapshotShardsService}, then the shard's state will be reported to master as {@code SUCCESS}.
+ * the {@code SnapshotShardsService}, then the shard's state will be reported to cluster-manager as {@code SUCCESS}.
  * Otherwise, it will be reported as {@code FAILED}.</li>
  *
- * <li>Once all the shards are reported to master as either {@code SUCCESS} or {@code FAILED} the {@code SnapshotsService} on the master
+ * <li>Once all the shards are reported to cluster-manager as either {@code SUCCESS} or {@code FAILED} the {@code SnapshotsService} on the master
  * will finish the snapshot process as all shard's states are now completed and hence the snapshot can be completed as explained in point 4
  * of the snapshot creation section above.</li>
  * </ol>
@@ -109,7 +109,7 @@
  *
  * <h2>Cloning a Snapshot</h2>
  *
- * <p>Cloning part of a snapshot is a process executed entirely on the master node. On a high level, the process of cloning a snapshot is
+ * <p>Cloning part of a snapshot is a process executed entirely on the cluster-manager node. On a high level, the process of cloning a snapshot is
  * analogous to that of creating a snapshot from data in the cluster except that the source of data files is the snapshot repository
  * instead of the data nodes. It begins with cloning all shards and then finalizes the cloned snapshot the same way a normal snapshot would
  * be finalized. Concretely, it is executed as follows:</p>
@@ -132,7 +132,7 @@
  *     failures of the relevant indices.</li>
  *     <li>Once all shard counts are known and the health of all source indices data has been verified, we populate the
  *     {@code SnapshotsInProgress.Entry#clones} map for the clone operation with the the relevant shard clone tasks.</li>
- *     <li>After the clone tasks have been added to the {@code SnapshotsInProgress.Entry}, master executes them on its snapshot thread-pool
+ *     <li>After the clone tasks have been added to the {@code SnapshotsInProgress.Entry}, cluster-manager executes them on its snapshot thread-pool
  *     by invoking {@link org.opensearch.repositories.Repository#cloneShardSnapshot} for each shard that is to be cloned. Each completed
  *     shard snapshot triggers a call to the {@link org.opensearch.snapshots.SnapshotsService#SHARD_STATE_EXECUTOR} which updates the
  *     clone's {@code SnapshotsInProgress.Entry} to mark the shard clone operation completed.</li>
@@ -151,7 +151,7 @@
  *
  * If multiple snapshot creation jobs are started at the same time, the data-node operations of multiple snapshots may run in parallel
  * across different shards. If multiple snapshots want to snapshot a certain shard, then the shard snapshots for that shard will be
- * executed one by one. This is enforced by the master node setting the shard's snapshot state to
+ * executed one by one. This is enforced by the cluster-manager node setting the shard's snapshot state to
  * {@link org.opensearch.cluster.SnapshotsInProgress.ShardSnapshotStatus#UNASSIGNED_QUEUED} for all but one snapshot. The order of
  * operations on a single shard is given by the order in which the snapshots were started.
  * As soon as all shards for a given snapshot have finished, it will be finalized as explained above. Finalization will happen one snapshot
diff --git a/server/src/main/java/org/opensearch/tasks/CancellableTask.java b/server/src/main/java/org/opensearch/tasks/CancellableTask.java
index 1eef8bb47abef..22806a749c686 100644
--- a/server/src/main/java/org/opensearch/tasks/CancellableTask.java
+++ b/server/src/main/java/org/opensearch/tasks/CancellableTask.java
@@ -33,20 +33,40 @@
 package org.opensearch.tasks;
 
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.TaskId;
 
 import java.util.Map;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.opensearch.search.SearchService.NO_TIMEOUT;
 
 /**
  * A task that can be canceled
+ *
+ * @opensearch.internal
  */
 public abstract class CancellableTask extends Task {
 
-    private volatile String reason;
-    private final AtomicBoolean cancelled = new AtomicBoolean(false);
+    private static class CancelledInfo {
+        String reason;
+        /**
+         * The time this task was cancelled as a wall clock time since epoch ({@link System#currentTimeMillis()} style).
+         */
+        Long cancellationStartTime;
+        /**
+         * The time this task was cancelled as a relative time ({@link System#nanoTime()} style).
+         */
+        Long cancellationStartTimeNanos;
+
+        public CancelledInfo(String reason) {
+            this.reason = reason;
+            this.cancellationStartTime = System.currentTimeMillis();
+            this.cancellationStartTimeNanos = System.nanoTime();
+        }
+    }
+
+    private final SetOnce<CancelledInfo> cancelledInfo = new SetOnce<>();
     private final TimeValue cancelAfterTimeInterval;
 
     public CancellableTask(long id, String type, String action, String description, TaskId parentTaskId, Map<String, String> headers) {
@@ -69,20 +89,15 @@ public CancellableTask(
     /**
      * This method is called by the task manager when this task is cancelled.
      */
-    final void cancel(String reason) {
+    public void cancel(String reason) {
         assert reason != null;
-        if (cancelled.compareAndSet(false, true)) {
-            this.reason = reason;
+        if (cancelledInfo.trySet(new CancelledInfo(reason))) {
             onCancelled();
         }
     }
 
-    /**
-     * Returns true if this task should be automatically cancelled if the coordinating node that
-     * requested this task left the cluster.
-     */
-    public boolean cancelOnParentLeaving() {
-        return true;
+    public boolean isCancelled() {
+        return cancelledInfo.get() != null;
     }
 
     /**
@@ -90,24 +105,41 @@ public boolean cancelOnParentLeaving() {
      */
     public abstract boolean shouldCancelChildrenOnCancellation();
 
-    public boolean isCancelled() {
-        return cancelled.get();
-    }
-
     public TimeValue getCancellationTimeout() {
         return cancelAfterTimeInterval;
     }
 
     /**
-     * The reason the task was cancelled or null if it hasn't been cancelled.
+     * Called after the task is cancelled so that it can take any actions that it has to take.
      */
+    protected void onCancelled() {}
+
+    /**
+     * Returns true if this task should be automatically cancelled if the coordinating node that
+     * requested this task left the cluster.
+     */
+    public boolean cancelOnParentLeaving() {
+        return true;
+    }
+
     @Nullable
-    public final String getReasonCancelled() {
-        return reason;
+    public Long getCancellationStartTime() {
+        CancelledInfo info = cancelledInfo.get();
+        return (info != null) ? info.cancellationStartTime : null;
+    }
+
+    @Nullable
+    public Long getCancellationStartTimeNanos() {
+        CancelledInfo info = cancelledInfo.get();
+        return (info != null) ? info.cancellationStartTimeNanos : null;
     }
 
     /**
-     * Called after the task is cancelled so that it can take any actions that it has to take.
+     * The reason the task was cancelled or null if it hasn't been cancelled.
      */
-    protected void onCancelled() {}
+    @Nullable
+    public String getReasonCancelled() {
+        CancelledInfo info = cancelledInfo.get();
+        return (info != null) ? info.reason : null;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/tasks/LoggingTaskListener.java b/server/src/main/java/org/opensearch/tasks/LoggingTaskListener.java
index 3a0c4eb560afc..88eaae4a480f8 100644
--- a/server/src/main/java/org/opensearch/tasks/LoggingTaskListener.java
+++ b/server/src/main/java/org/opensearch/tasks/LoggingTaskListener.java
@@ -39,6 +39,8 @@
 /**
  * A TaskListener that just logs the response at the info level. Used when we
  * need a listener but aren't returning the result to the user.
+ *
+ * @opensearch.internal
  */
 public final class LoggingTaskListener<Response> implements TaskListener<Response> {
     private static final Logger logger = LogManager.getLogger(LoggingTaskListener.class);
diff --git a/server/src/main/java/org/opensearch/tasks/RawTaskStatus.java b/server/src/main/java/org/opensearch/tasks/RawTaskStatus.java
index f9b4ce23f1ae1..28950f5a713fc 100644
--- a/server/src/main/java/org/opensearch/tasks/RawTaskStatus.java
+++ b/server/src/main/java/org/opensearch/tasks/RawTaskStatus.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.tasks;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -48,6 +48,8 @@
 
 /**
  * Raw, unparsed status from the task results index.
+ *
+ * @opensearch.internal
  */
 public class RawTaskStatus implements Task.Status {
     public static final String NAME = "raw";
@@ -73,7 +75,7 @@ public void writeTo(StreamOutput out) throws IOException {
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         try (InputStream stream = status.streamInput()) {
-            return builder.rawValue(stream, XContentHelper.xContentType(status));
+            return builder.rawValue(stream, MediaTypeRegistry.xContentType(status));
         }
     }
 
@@ -84,7 +86,7 @@ public String getWriteableName() {
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     /**
diff --git a/server/src/main/java/org/opensearch/tasks/SearchBackpressureTask.java b/server/src/main/java/org/opensearch/tasks/SearchBackpressureTask.java
new file mode 100644
index 0000000000000..0cab67e35ab02
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/SearchBackpressureTask.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+/**
+ * A task related to search backpressure
+ *
+ * @opensearch.internal
+ */
+public interface SearchBackpressureTask {}
diff --git a/server/src/main/java/org/opensearch/tasks/SearchShardTaskCancellationStats.java b/server/src/main/java/org/opensearch/tasks/SearchShardTaskCancellationStats.java
new file mode 100644
index 0000000000000..e6ce092d7516e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/SearchShardTaskCancellationStats.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Holds monitoring service stats specific to search shard task.
+ */
+public class SearchShardTaskCancellationStats implements ToXContentObject, Writeable {
+
+    private final long currentLongRunningCancelledTaskCount;
+    private final long totalLongRunningCancelledTaskCount;
+
+    public SearchShardTaskCancellationStats(long currentTaskCount, long totalTaskCount) {
+        this.currentLongRunningCancelledTaskCount = currentTaskCount;
+        this.totalLongRunningCancelledTaskCount = totalTaskCount;
+    }
+
+    public SearchShardTaskCancellationStats(StreamInput in) throws IOException {
+        this.currentLongRunningCancelledTaskCount = in.readVLong();
+        this.totalLongRunningCancelledTaskCount = in.readVLong();
+    }
+
+    // package private for testing
+    protected long getCurrentLongRunningCancelledTaskCount() {
+        return this.currentLongRunningCancelledTaskCount;
+    }
+
+    // package private for testing
+    protected long getTotalLongRunningCancelledTaskCount() {
+        return this.totalLongRunningCancelledTaskCount;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field("current_count_post_cancel", currentLongRunningCancelledTaskCount);
+        builder.field("total_count_post_cancel", totalLongRunningCancelledTaskCount);
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(currentLongRunningCancelledTaskCount);
+        out.writeVLong(totalLongRunningCancelledTaskCount);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SearchShardTaskCancellationStats that = (SearchShardTaskCancellationStats) o;
+        return currentLongRunningCancelledTaskCount == that.currentLongRunningCancelledTaskCount
+            && totalLongRunningCancelledTaskCount == that.totalLongRunningCancelledTaskCount;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(currentLongRunningCancelledTaskCount, totalLongRunningCancelledTaskCount);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/Task.java b/server/src/main/java/org/opensearch/tasks/Task.java
index ad9d5c3f04411..22555bce4545c 100644
--- a/server/src/main/java/org/opensearch/tasks/Task.java
+++ b/server/src/main/java/org/opensearch/tasks/Task.java
@@ -32,25 +32,55 @@
 
 package org.opensearch.tasks;
 
-import org.opensearch.action.ActionResponse;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.core.tasks.resourcetracker.ResourceStatsType;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageInfo;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageMetric;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceStats;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.core.tasks.resourcetracker.TaskThreadUsage;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Current task information
+ *
+ * @opensearch.internal
  */
 public class Task {
 
+    private static final Logger logger = LogManager.getLogger(Task.class);
+
     /**
      * The request header to mark tasks with specific ids
      */
     public static final String X_OPAQUE_ID = "X-Opaque-Id";
 
+    private static final String TOTAL = "total";
+
+    private static final String AVERAGE = "average";
+
+    private static final String MIN = "min";
+
+    private static final String MAX = "max";
+
     private final long id;
 
     private final String type;
@@ -63,6 +93,17 @@ public class Task {
 
     private final Map<String, String> headers;
 
+    private final Map<Long, List<ThreadResourceInfo>> resourceStats;
+
+    private final List<NotifyOnceListener<Task>> resourceTrackingCompletionListeners;
+
+    /**
+     * Keeps track of the number of active resource tracking threads for this task. It is initialized to 1 to track
+     * the task's own/self thread. When this value becomes 0, all threads have been marked inactive and the resource
+     * tracking can be stopped for this task.
+     */
+    private final AtomicInteger numActiveResourceTrackingThreads = new AtomicInteger(1);
+
     /**
      * The task's start time as a wall clock time since epoch ({@link System#currentTimeMillis()} style).
      */
@@ -74,7 +115,18 @@ public class Task {
     private final long startTimeNanos;
 
     public Task(long id, String type, String action, String description, TaskId parentTask, Map<String, String> headers) {
-        this(id, type, action, description, parentTask, System.currentTimeMillis(), System.nanoTime(), headers);
+        this(
+            id,
+            type,
+            action,
+            description,
+            parentTask,
+            System.currentTimeMillis(),
+            System.nanoTime(),
+            headers,
+            new ConcurrentHashMap<>(),
+            new ArrayList<>()
+        );
     }
 
     public Task(
@@ -85,7 +137,9 @@ public Task(
         TaskId parentTask,
         long startTime,
         long startTimeNanos,
-        Map<String, String> headers
+        Map<String, String> headers,
+        ConcurrentHashMap<Long, List<ThreadResourceInfo>> resourceStats,
+        List<NotifyOnceListener<Task>> resourceTrackingCompletionListeners
     ) {
         this.id = id;
         this.type = type;
@@ -95,6 +149,8 @@ public Task(
         this.startTime = startTime;
         this.startTimeNanos = startTimeNanos;
         this.headers = headers;
+        this.resourceStats = resourceStats;
+        this.resourceTrackingCompletionListeners = resourceTrackingCompletionListeners;
     }
 
     /**
@@ -108,19 +164,56 @@ public Task(
      *            generate data?
      */
     public final TaskInfo taskInfo(String localNodeId, boolean detailed) {
+        return taskInfo(localNodeId, detailed, detailed == false);
+    }
+
+    /**
+     * Build a version of the task status you can throw over the wire and back
+     * with the option to include resource stats or not.
+     * This method is only used during creating TaskResult to avoid storing resource information into the task index.
+     *
+     * @param excludeStats should information exclude resource stats.
+     *                     By default, detailed flag is used to control including resource information.
+     *                     But inorder to avoid storing resource stats into task index as strict mapping is enforced and breaks when adding this field.
+     *                     In the future, task-index-mapping.json can be modified to add resource stats.
+     */
+    private TaskInfo taskInfo(String localNodeId, boolean detailed, boolean excludeStats) {
         String description = null;
         Task.Status status = null;
+        TaskResourceStats resourceStats = null;
         if (detailed) {
             description = getDescription();
             status = getStatus();
         }
-        return taskInfo(localNodeId, description, status);
+        if (excludeStats == false) {
+            resourceStats = new TaskResourceStats(new HashMap<>() {
+                {
+                    put(TOTAL, getTotalResourceStats());
+                    put(AVERAGE, getAverageResourceStats());
+                    put(MIN, getMinResourceStats());
+                    put(MAX, getMaxResourceStats());
+                }
+            }, getThreadUsage());
+        }
+        return taskInfo(localNodeId, description, status, resourceStats);
     }
 
     /**
-     * Build a proper {@link TaskInfo} for this task.
+     * Build a {@link TaskInfo} for this task without resource stats.
      */
     protected final TaskInfo taskInfo(String localNodeId, String description, Status status) {
+        return taskInfo(localNodeId, description, status, null);
+    }
+
+    /**
+     * Build a proper {@link TaskInfo} for this task.
+     */
+    protected final TaskInfo taskInfo(String localNodeId, String description, Status status, TaskResourceStats resourceStats) {
+        boolean cancelled = this instanceof CancellableTask && ((CancellableTask) this).isCancelled();
+        Long cancellationStartTime = null;
+        if (cancelled) {
+            cancellationStartTime = ((CancellableTask) this).getCancellationStartTime();
+        }
         return new TaskInfo(
             new TaskId(localNodeId, getId()),
             getType(),
@@ -130,9 +223,11 @@ protected final TaskInfo taskInfo(String localNodeId, String description, Status
             startTime,
             System.nanoTime() - startTimeNanos,
             this instanceof CancellableTask,
-            this instanceof CancellableTask && ((CancellableTask) this).isCancelled(),
+            cancelled,
             parentTask,
-            headers
+            headers,
+            resourceStats,
+            cancellationStartTime
         );
     }
 
@@ -195,6 +290,206 @@ public Status getStatus() {
         return null;
     }
 
+    /**
+     * Returns thread level resource consumption of the task
+     */
+    public Map<Long, List<ThreadResourceInfo>> getResourceStats() {
+        return Collections.unmodifiableMap(resourceStats);
+    }
+
+    /**
+     * Returns current total resource usage of the task.
+     * Currently, this method is only called on demand, during get and listing of tasks.
+     * In the future, these values can be cached as an optimization.
+     */
+    public TaskResourceUsage getTotalResourceStats() {
+        return new TaskResourceUsage(getTotalResourceUtilization(ResourceStats.CPU), getTotalResourceUtilization(ResourceStats.MEMORY));
+    }
+
+    /**
+     * Returns current average per-execution resource usage of the task.
+     */
+    public TaskResourceUsage getAverageResourceStats() {
+        return new TaskResourceUsage(getAverageResourceUtilization(ResourceStats.CPU), getAverageResourceUtilization(ResourceStats.MEMORY));
+    }
+
+    /**
+     * Returns current min per-execution resource usage of the task.
+     */
+    public TaskResourceUsage getMinResourceStats() {
+        return new TaskResourceUsage(getMinResourceUtilization(ResourceStats.CPU), getMinResourceUtilization(ResourceStats.MEMORY));
+    }
+
+    /**
+     * Returns current max per-execution resource usage of the task.
+     */
+    public TaskResourceUsage getMaxResourceStats() {
+        return new TaskResourceUsage(getMaxResourceUtilization(ResourceStats.CPU), getMaxResourceUtilization(ResourceStats.MEMORY));
+    }
+
+    /**
+     * Returns total resource consumption for a specific task stat.
+     */
+    public long getTotalResourceUtilization(ResourceStats stats) {
+        long totalResourceConsumption = 0L;
+        for (List<ThreadResourceInfo> threadResourceInfosList : resourceStats.values()) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfosList) {
+                final ResourceUsageInfo.ResourceStatsInfo statsInfo = threadResourceInfo.getResourceUsageInfo().getStatsInfo().get(stats);
+                if (threadResourceInfo.getStatsType().isOnlyForAnalysis() == false && statsInfo != null) {
+                    totalResourceConsumption += statsInfo.getTotalValue();
+                }
+            }
+        }
+        return totalResourceConsumption;
+    }
+
+    /**
+     * Returns average per-execution resource consumption for a specific task stat.
+     */
+    private long getAverageResourceUtilization(ResourceStats stats) {
+        long totalResourceConsumption = 0L;
+        int threadResourceInfoCount = 0;
+        for (List<ThreadResourceInfo> threadResourceInfosList : resourceStats.values()) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfosList) {
+                final ResourceUsageInfo.ResourceStatsInfo statsInfo = threadResourceInfo.getResourceUsageInfo().getStatsInfo().get(stats);
+                if (threadResourceInfo.getStatsType().isOnlyForAnalysis() == false && statsInfo != null) {
+                    totalResourceConsumption += statsInfo.getTotalValue();
+                    threadResourceInfoCount++;
+                }
+            }
+        }
+        return (threadResourceInfoCount > 0) ? totalResourceConsumption / threadResourceInfoCount : 0;
+    }
+
+    /**
+     * Returns minimum per-execution resource consumption for a specific task stat.
+     */
+    private long getMinResourceUtilization(ResourceStats stats) {
+        if (resourceStats.size() == 0) {
+            return 0L;
+        }
+        long minResourceConsumption = Long.MAX_VALUE;
+        for (List<ThreadResourceInfo> threadResourceInfosList : resourceStats.values()) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfosList) {
+                final ResourceUsageInfo.ResourceStatsInfo statsInfo = threadResourceInfo.getResourceUsageInfo().getStatsInfo().get(stats);
+                if (threadResourceInfo.getStatsType().isOnlyForAnalysis() == false && statsInfo != null) {
+                    minResourceConsumption = Math.min(minResourceConsumption, statsInfo.getTotalValue());
+                }
+            }
+        }
+        return minResourceConsumption;
+    }
+
+    /**
+     * Returns maximum per-execution resource consumption for a specific task stat.
+     */
+    private long getMaxResourceUtilization(ResourceStats stats) {
+        long maxResourceConsumption = 0L;
+        for (List<ThreadResourceInfo> threadResourceInfosList : resourceStats.values()) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfosList) {
+                final ResourceUsageInfo.ResourceStatsInfo statsInfo = threadResourceInfo.getResourceUsageInfo().getStatsInfo().get(stats);
+                if (threadResourceInfo.getStatsType().isOnlyForAnalysis() == false && statsInfo != null) {
+                    maxResourceConsumption = Math.max(maxResourceConsumption, statsInfo.getTotalValue());
+                }
+            }
+        }
+        return maxResourceConsumption;
+    }
+
+    /**
+     * Returns the total and active number of thread executions for the task.
+     */
+    public TaskThreadUsage getThreadUsage() {
+        int numThreadExecutions = 0;
+        int activeThreads = 0;
+        for (List<ThreadResourceInfo> threadResourceInfosList : resourceStats.values()) {
+            numThreadExecutions += threadResourceInfosList.size();
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfosList) {
+                if (threadResourceInfo.isActive()) {
+                    activeThreads++;
+                }
+            }
+        }
+        return new TaskThreadUsage(numThreadExecutions, activeThreads);
+    }
+
+    /**
+     * Adds thread's starting resource consumption information
+     * @param threadId ID of the thread
+     * @param statsType stats type
+     * @param resourceUsageMetrics resource consumption metrics of the thread
+     * @throws IllegalStateException matching active thread entry was found which is not expected.
+     */
+    public void startThreadResourceTracking(long threadId, ResourceStatsType statsType, ResourceUsageMetric... resourceUsageMetrics) {
+        final List<ThreadResourceInfo> threadResourceInfoList = resourceStats.computeIfAbsent(threadId, k -> new ArrayList<>());
+        // active thread entry should not be present in the list
+        for (ThreadResourceInfo threadResourceInfo : threadResourceInfoList) {
+            if (threadResourceInfo.getStatsType() == statsType && threadResourceInfo.isActive()) {
+                throw new IllegalStateException(
+                    "unexpected active thread resource entry present [" + threadId + "]:[" + threadResourceInfo + "]"
+                );
+            }
+        }
+        threadResourceInfoList.add(new ThreadResourceInfo(threadId, statsType, resourceUsageMetrics));
+        incrementResourceTrackingThreads();
+    }
+
+    /**
+     * This method is used to update the resource consumption stats so that the data isn't too stale for long-running task.
+     * If active thread entry is present in the list, the entry is updated. If one is not found, it throws an exception.
+     * @param threadId ID of the thread
+     * @param statsType stats type
+     * @param resourceUsageMetrics resource consumption metrics of the thread
+     * @throws IllegalStateException if no matching active thread entry was found.
+     */
+    public void updateThreadResourceStats(long threadId, ResourceStatsType statsType, ResourceUsageMetric... resourceUsageMetrics) {
+        final List<ThreadResourceInfo> threadResourceInfoList = resourceStats.get(threadId);
+        if (threadResourceInfoList != null) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfoList) {
+                // the active entry present in the list is updated
+                if (threadResourceInfo.getStatsType() == statsType && threadResourceInfo.isActive()) {
+                    threadResourceInfo.recordResourceUsageMetrics(resourceUsageMetrics);
+                    return;
+                }
+            }
+        }
+        throw new IllegalStateException("cannot update if active thread resource entry is not present");
+    }
+
+    /**
+     * Record the thread's final resource consumption values.
+     * If active thread entry is present in the list, the entry is updated. If one is not found, it throws an exception.
+     * @param threadId ID of the thread
+     * @param statsType stats type
+     * @param resourceUsageMetrics resource consumption metrics of the thread
+     * @throws IllegalStateException if no matching active thread entry was found.
+     */
+    public void stopThreadResourceTracking(long threadId, ResourceStatsType statsType, ResourceUsageMetric... resourceUsageMetrics) {
+        final List<ThreadResourceInfo> threadResourceInfoList = resourceStats.get(threadId);
+        if (threadResourceInfoList != null) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfoList) {
+                if (threadResourceInfo.getStatsType() == statsType && threadResourceInfo.isActive()) {
+                    threadResourceInfo.setActive(false);
+                    threadResourceInfo.recordResourceUsageMetrics(resourceUsageMetrics);
+                    decrementResourceTrackingThreads();
+                    return;
+                }
+            }
+        }
+        throw new IllegalStateException("cannot update final values if active thread resource entry is not present");
+    }
+
+    /**
+     * Individual tasks can override this if they want to support task resource tracking. We just need to make sure that
+     * the ThreadPool on which the task runs on have runnable wrapper similar to
+     * {@link org.opensearch.common.util.concurrent.OpenSearchExecutors#newAutoQueueFixed}
+     *
+     * @return true if resource tracking is supported by the task
+     */
+    public boolean supportsResourceTracking() {
+        return false;
+    }
+
     /**
      * Report of the internal status of a task. These can vary wildly from task
      * to task because each task is implemented differently but we should try
@@ -216,15 +511,74 @@ public String getHeader(String header) {
         return headers.get(header);
     }
 
-    public TaskResult result(DiscoveryNode node, Exception error) throws IOException {
-        return new TaskResult(taskInfo(node.getId(), true), error);
+    public TaskResult result(final String nodeId, Exception error) throws IOException {
+        return new TaskResult(taskInfo(nodeId, true, true), error);
     }
 
-    public TaskResult result(DiscoveryNode node, ActionResponse response) throws IOException {
+    public TaskResult result(final String nodeId, ActionResponse response) throws IOException {
         if (response instanceof ToXContent) {
-            return new TaskResult(taskInfo(node.getId(), true), (ToXContent) response);
+            return new TaskResult(taskInfo(nodeId, true, true), (ToXContent) response);
         } else {
             throw new IllegalStateException("response has to implement ToXContent to be able to store the results");
         }
     }
+
+    /**
+     * Registers a task resource tracking completion listener on this task if resource tracking is still active.
+     * Returns true on successful subscription, false otherwise.
+     */
+    public boolean addResourceTrackingCompletionListener(NotifyOnceListener<Task> listener) {
+        if (numActiveResourceTrackingThreads.get() > 0) {
+            resourceTrackingCompletionListeners.add(listener);
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Increments the number of active resource tracking threads.
+     *
+     * @return the number of active resource tracking threads.
+     */
+    public int incrementResourceTrackingThreads() {
+        return numActiveResourceTrackingThreads.incrementAndGet();
+    }
+
+    /**
+     * Decrements the number of active resource tracking threads.
+     * This method is called when threads finish execution, and also when the task is unregistered (to mark the task's
+     * own thread as complete). When the active thread count becomes zero, the onTaskResourceTrackingCompleted method
+     * is called exactly once on all registered listeners.
+     *
+     * Since a task is unregistered after the message is processed, it implies that the threads responsible to produce
+     * the response must have started prior to it (i.e. startThreadResourceTracking called before unregister).
+     * This ensures that the number of active threads doesn't drop to zero pre-maturely.
+     *
+     * Rarely, some threads may even start execution after the task is unregistered. As resource stats are piggy-backed
+     * with the response, any thread usage info captured after the task is unregistered may be irrelevant.
+     *
+     * @return the number of active resource tracking threads.
+     */
+    public int decrementResourceTrackingThreads() {
+        int count = numActiveResourceTrackingThreads.decrementAndGet();
+
+        if (count == 0) {
+            List<Exception> listenerExceptions = new ArrayList<>();
+            resourceTrackingCompletionListeners.forEach(listener -> {
+                try {
+                    listener.onResponse(this);
+                } catch (Exception e1) {
+                    try {
+                        listener.onFailure(e1);
+                    } catch (Exception e2) {
+                        listenerExceptions.add(e2);
+                    }
+                }
+            });
+            ExceptionsHelper.maybeThrowRuntimeAndSuppress(listenerExceptions);
+        }
+
+        return count;
+    }
 }
diff --git a/server/src/main/java/org/opensearch/tasks/TaskAwareRequest.java b/server/src/main/java/org/opensearch/tasks/TaskAwareRequest.java
index b10e85ae35dc6..6913f6cfc375c 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskAwareRequest.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskAwareRequest.java
@@ -32,10 +32,14 @@
 
 package org.opensearch.tasks;
 
+import org.opensearch.core.tasks.TaskId;
+
 import java.util.Map;
 
 /**
  * An interface for a request that can be used to register a task manager task
+ *
+ * @opensearch.internal
  */
 public interface TaskAwareRequest {
     /**
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancellation.java b/server/src/main/java/org/opensearch/tasks/TaskCancellation.java
new file mode 100644
index 0000000000000..9b61b2454b53c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskCancellation.java
@@ -0,0 +1,130 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.core.action.ActionListener;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * TaskCancellation represents a task eligible for cancellation.
+ * It doesn't guarantee that the task will actually get cancelled or not; that decision is left to the caller.
+ *
+ * It contains a list of cancellation reasons along with callbacks that are invoked when cancel() is called.
+ *
+ * @opensearch.internal
+ */
+public class TaskCancellation implements Comparable<TaskCancellation> {
+    private final CancellableTask task;
+    private final List<Reason> reasons;
+    private final List<Runnable> onCancelCallbacks;
+
+    public TaskCancellation(CancellableTask task, List<Reason> reasons, List<Runnable> onCancelCallbacks) {
+        this.task = task;
+        this.reasons = reasons;
+        this.onCancelCallbacks = onCancelCallbacks;
+    }
+
+    public CancellableTask getTask() {
+        return task;
+    }
+
+    public List<Reason> getReasons() {
+        return reasons;
+    }
+
+    public String getReasonString() {
+        return reasons.stream().map(Reason::getMessage).collect(Collectors.joining(", "));
+    }
+
+    /**
+     * Cancels the task and invokes all onCancelCallbacks.
+     */
+    public void cancel() {
+        if (isEligibleForCancellation() == false) {
+            return;
+        }
+
+        task.cancel(getReasonString());
+        runOnCancelCallbacks();
+    }
+
+    /**
+     *  Cancels the task and its descendants and invokes all onCancelCallbacks.
+     */
+    public void cancelTaskAndDescendants(TaskManager taskManager) {
+        if (isEligibleForCancellation() == false) {
+            return;
+        }
+
+        taskManager.cancelTaskAndDescendants(task, getReasonString(), false, ActionListener.wrap(() -> {}));
+        runOnCancelCallbacks();
+    }
+
+    /**
+     * invokes all onCancelCallbacks.
+     */
+    private void runOnCancelCallbacks() {
+        List<Exception> exceptions = new ArrayList<>();
+        for (Runnable callback : onCancelCallbacks) {
+            try {
+                callback.run();
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+    }
+
+    /**
+     * Returns the sum of all cancellation scores.
+     *
+     * A zero score indicates no reason to cancel the task.
+     * A task with a higher score suggests greater possibility of recovering the node when it is cancelled.
+     */
+    public int totalCancellationScore() {
+        return reasons.stream().mapToInt(Reason::getCancellationScore).sum();
+    }
+
+    /**
+     * A task is eligible for cancellation if it has one or more cancellation reasons, and is not already cancelled.
+     */
+    public boolean isEligibleForCancellation() {
+        return (task.isCancelled() == false) && (reasons.size() > 0);
+    }
+
+    @Override
+    public int compareTo(TaskCancellation other) {
+        return Integer.compare(totalCancellationScore(), other.totalCancellationScore());
+    }
+
+    /**
+     * Represents the cancellation reason for a task.
+     */
+    public static class Reason {
+        private final String message;
+        private final int cancellationScore;
+
+        public Reason(String message, int cancellationScore) {
+            this.message = message;
+            this.cancellationScore = cancellationScore;
+        }
+
+        public String getMessage() {
+            return message;
+        }
+
+        public int getCancellationScore() {
+            return cancellationScore;
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringService.java b/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringService.java
new file mode 100644
index 0000000000000..343d4571593a7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringService.java
@@ -0,0 +1,179 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.common.metrics.CounterMetric;
+import org.opensearch.threadpool.Scheduler;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+/**
+ * This monitoring service is responsible to track long-running(defined by a threshold) cancelled tasks as part of
+ * node stats.
+ */
+public class TaskCancellationMonitoringService extends AbstractLifecycleComponent implements TaskManager.TaskEventListeners {
+
+    private static final Logger logger = LogManager.getLogger(TaskCancellationMonitoringService.class);
+    private final static List<Class<? extends CancellableTask>> TASKS_TO_TRACK = Arrays.asList(SearchShardTask.class);
+
+    private volatile Scheduler.Cancellable scheduledFuture;
+    private final ThreadPool threadPool;
+    private final TaskManager taskManager;
+    /**
+     * This is to keep track of currently running cancelled tasks. This is needed to accurately calculate cumulative
+     * sum(from genesis) of cancelled tasks which have been running beyond a threshold and avoid double count
+     * problem.
+     * For example:
+     * A task M was cancelled at some point of time and continues to run for long. This Monitoring service sees this
+     * M for the first time and adds it as part of stats. In next iteration of monitoring service, it might see
+     * this M(if still running) again, but using below map we will not double count this task as part of our cumulative
+     * metric.
+     */
+    private final Map<Long, Boolean> cancelledTaskTracker;
+    /**
+     *  This map holds statistics for each cancellable task type.
+     */
+    private final Map<Class<? extends CancellableTask>, TaskCancellationStatsHolder> cancellationStatsHolder;
+    private final TaskCancellationMonitoringSettings taskCancellationMonitoringSettings;
+
+    public TaskCancellationMonitoringService(
+        ThreadPool threadPool,
+        TaskManager taskManager,
+        TaskCancellationMonitoringSettings taskCancellationMonitoringSettings
+    ) {
+        this.threadPool = threadPool;
+        this.taskManager = taskManager;
+        this.taskCancellationMonitoringSettings = taskCancellationMonitoringSettings;
+        this.cancelledTaskTracker = new ConcurrentHashMap<>();
+        cancellationStatsHolder = TASKS_TO_TRACK.stream()
+            .collect(Collectors.toConcurrentMap(task -> task, task -> new TaskCancellationStatsHolder()));
+        taskManager.addTaskEventListeners(this);
+    }
+
+    void doRun() {
+        if (!taskCancellationMonitoringSettings.isEnabled() || this.cancelledTaskTracker.isEmpty()) {
+            return;
+        }
+        Map<Class<? extends CancellableTask>, List<CancellableTask>> taskCancellationListByType = getCurrentRunningTasksPostCancellation();
+        taskCancellationListByType.forEach((key, value) -> {
+            long uniqueTasksRunningCount = value.stream().filter(task -> {
+                if (this.cancelledTaskTracker.containsKey(task.getId()) && !this.cancelledTaskTracker.get(task.getId())) {
+                    // Mark it as seen by the stats logic.
+                    this.cancelledTaskTracker.put(task.getId(), true);
+                    return true;
+                } else {
+                    return false;
+                }
+            }).count();
+            cancellationStatsHolder.get(key).totalLongRunningCancelledTaskCount.inc(uniqueTasksRunningCount);
+        });
+    }
+
+    @Override
+    protected void doStart() {
+        scheduledFuture = threadPool.scheduleWithFixedDelay(() -> {
+            try {
+                doRun();
+            } catch (Exception e) {
+                logger.debug("Exception occurred in Task monitoring service", e);
+            }
+        }, taskCancellationMonitoringSettings.getInterval(), ThreadPool.Names.GENERIC);
+    }
+
+    @Override
+    protected void doStop() {
+        if (scheduledFuture != null) {
+            scheduledFuture.cancel();
+        }
+    }
+
+    @Override
+    protected void doClose() throws IOException {
+
+    }
+
+    // For testing
+    protected Map<Long, Boolean> getCancelledTaskTracker() {
+        return this.cancelledTaskTracker;
+    }
+
+    /**
+     * Invoked when a task is completed. This helps us to disable monitoring service when there are no cancelled tasks
+     * running to avoid wasteful work.
+     * @param task task which got completed.
+     */
+    @Override
+    public void onTaskCompleted(Task task) {
+        if (!TASKS_TO_TRACK.contains(task.getClass())) {
+            return;
+        }
+        this.cancelledTaskTracker.entrySet().removeIf(entry -> entry.getKey() == task.getId());
+    }
+
+    /**
+     * Invoked when a task is cancelled. This is to keep track of tasks being cancelled. More importantly also helps
+     * us to enable this monitoring service only when needed.
+     * @param task task which got cancelled.
+     */
+    @Override
+    public void onTaskCancelled(CancellableTask task) {
+        if (!TASKS_TO_TRACK.contains(task.getClass())) {
+            return;
+        }
+        // Add task to tracker and mark it as not seen(false) yet by the stats logic.
+        this.cancelledTaskTracker.putIfAbsent(task.getId(), false);
+    }
+
+    public TaskCancellationStats stats() {
+        Map<Class<? extends CancellableTask>, List<CancellableTask>> currentRunningCancelledTasks =
+            getCurrentRunningTasksPostCancellation();
+        return new TaskCancellationStats(
+            new SearchShardTaskCancellationStats(
+                Optional.of(currentRunningCancelledTasks).map(mapper -> mapper.get(SearchShardTask.class)).map(List::size).orElse(0),
+                cancellationStatsHolder.get(SearchShardTask.class).totalLongRunningCancelledTaskCount.count()
+            )
+        );
+    }
+
+    private Map<Class<? extends CancellableTask>, List<CancellableTask>> getCurrentRunningTasksPostCancellation() {
+        long currentTimeInNanos = System.nanoTime();
+
+        return taskManager.getCancellableTasks()
+            .values()
+            .stream()
+            .filter(task -> TASKS_TO_TRACK.contains(task.getClass()))
+            .filter(CancellableTask::isCancelled)
+            .filter(task -> {
+                long runningTimeSinceCancellationSeconds = TimeUnit.NANOSECONDS.toSeconds(
+                    currentTimeInNanos - task.getCancellationStartTimeNanos()
+                );
+                return runningTimeSinceCancellationSeconds >= taskCancellationMonitoringSettings.getDuration().getSeconds();
+            })
+            .collect(Collectors.groupingBy(CancellableTask::getClass, Collectors.toList()));
+    }
+
+    /**
+     * Holds stats related to monitoring service
+     */
+    public static class TaskCancellationStatsHolder {
+        CounterMetric totalLongRunningCancelledTaskCount = new CounterMetric();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringSettings.java b/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringSettings.java
new file mode 100644
index 0000000000000..d4ec99873d584
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskCancellationMonitoringSettings.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Settings related to task cancellation monitoring service.
+ */
+public class TaskCancellationMonitoringSettings {
+
+    public static final long INTERVAL_MILLIS_SETTING_DEFAULT_VALUE = 5000;
+    public static final long DURATION_MILLIS_SETTING_DEFAULT_VALUE = 10000;
+    public static final boolean IS_ENABLED_SETTING_DEFAULT_VALUE = true;
+
+    /**
+     * Defines the interval(in millis) at which task cancellation service monitors and gather stats.
+     */
+    public static final Setting<Long> INTERVAL_MILLIS_SETTING = Setting.longSetting(
+        "task_cancellation.interval_millis",
+        INTERVAL_MILLIS_SETTING_DEFAULT_VALUE,
+        1,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Setting which defines the duration threshold(in millis) of current running cancelled tasks above which they
+     * are tracked as part of stats.
+     */
+    public static final Setting<Long> DURATION_MILLIS_SETTING = Setting.longSetting(
+        "task_cancellation.duration_millis",
+        DURATION_MILLIS_SETTING_DEFAULT_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Setting to enable/disable monitoring service.
+     */
+    public static final Setting<Boolean> IS_ENABLED_SETTING = Setting.boolSetting(
+        "task_cancellation.enabled",
+        IS_ENABLED_SETTING_DEFAULT_VALUE,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private final TimeValue interval;
+    private TimeValue duration;
+    private final AtomicBoolean isEnabled;
+    private final Settings settings;
+    private final ClusterSettings clusterSettings;
+
+    public TaskCancellationMonitoringSettings(Settings settings, ClusterSettings clusterSettings) {
+        this.settings = settings;
+        this.clusterSettings = clusterSettings;
+        this.interval = new TimeValue(INTERVAL_MILLIS_SETTING.get(settings));
+        this.duration = new TimeValue(DURATION_MILLIS_SETTING.get(settings));
+        this.isEnabled = new AtomicBoolean(IS_ENABLED_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(IS_ENABLED_SETTING, this::setIsEnabled);
+        clusterSettings.addSettingsUpdateConsumer(DURATION_MILLIS_SETTING, this::setDurationMillis);
+    }
+
+    public TimeValue getInterval() {
+        return this.interval;
+    }
+
+    public TimeValue getDuration() {
+        return this.duration;
+    }
+
+    public void setDurationMillis(long durationMillis) {
+        this.duration = new TimeValue(durationMillis);
+    }
+
+    public boolean isEnabled() {
+        return isEnabled.get();
+    }
+
+    public void setIsEnabled(boolean isEnabled) {
+        this.isEnabled.set(isEnabled);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancellationService.java b/server/src/main/java/org/opensearch/tasks/TaskCancellationService.java
index aebd91b0041ac..4a97513d8f81a 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskCancellationService.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskCancellationService.java
@@ -37,26 +37,32 @@
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchSecurityException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.ChannelActionListener;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.EmptyTransportResponseHandler;
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.Collection;
 import java.util.List;
 
+/**
+ * Service used to cancel a task
+ *
+ * @opensearch.internal
+ */
 public class TaskCancellationService {
     public static final String BAN_PARENT_ACTION_NAME = "internal:admin/tasks/ban";
     private static final Logger logger = LogManager.getLogger(TaskCancellationService.class);
diff --git a/server/src/main/java/org/opensearch/tasks/TaskCancellationStats.java b/server/src/main/java/org/opensearch/tasks/TaskCancellationStats.java
new file mode 100644
index 0000000000000..cca898fdd844f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskCancellationStats.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Holds stats related to task cancellation.
+ */
+public class TaskCancellationStats implements ToXContentFragment, Writeable {
+
+    private final SearchShardTaskCancellationStats searchShardTaskCancellationStats;
+
+    public TaskCancellationStats(SearchShardTaskCancellationStats searchShardTaskCancellationStats) {
+        this.searchShardTaskCancellationStats = searchShardTaskCancellationStats;
+    }
+
+    public TaskCancellationStats(StreamInput in) throws IOException {
+        searchShardTaskCancellationStats = new SearchShardTaskCancellationStats(in);
+    }
+
+    // package private for testing
+    protected SearchShardTaskCancellationStats getSearchShardTaskCancellationStats() {
+        return this.searchShardTaskCancellationStats;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject("task_cancellation");
+        builder.field("search_shard_task", searchShardTaskCancellationStats);
+        return builder.endObject();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        searchShardTaskCancellationStats.writeTo(out);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        TaskCancellationStats that = (TaskCancellationStats) o;
+        return Objects.equals(searchShardTaskCancellationStats, that.searchShardTaskCancellationStats);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(searchShardTaskCancellationStats);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/TaskInfo.java b/server/src/main/java/org/opensearch/tasks/TaskInfo.java
index cf77eaf540ee6..b51240f234e39 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskInfo.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskInfo.java
@@ -33,18 +33,21 @@
 package org.opensearch.tasks;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParserHelper;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceStats;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParserHelper;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -52,8 +55,8 @@
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Information about a currently running task.
@@ -62,6 +65,8 @@
  * references as well as mutable state. That makes it impractical to send tasks over transport channels
  * and use in APIs. Instead, immutable and writeable TaskInfo objects are used to represent
  * snapshot information about currently running tasks.
+ *
+ * @opensearch.internal
  */
 public final class TaskInfo implements Writeable, ToXContentFragment {
     private final TaskId taskId;
@@ -82,10 +87,14 @@ public final class TaskInfo implements Writeable, ToXContentFragment {
 
     private final boolean cancelled;
 
+    private final Long cancellationStartTime;
+
     private final TaskId parentTaskId;
 
     private final Map<String, String> headers;
 
+    private final TaskResourceStats resourceStats;
+
     public TaskInfo(
         TaskId taskId,
         String type,
@@ -97,7 +106,40 @@ public TaskInfo(
         boolean cancellable,
         boolean cancelled,
         TaskId parentTaskId,
-        Map<String, String> headers
+        Map<String, String> headers,
+        TaskResourceStats resourceStats
+    ) {
+        this(
+            taskId,
+            type,
+            action,
+            description,
+            status,
+            startTime,
+            runningTimeNanos,
+            cancellable,
+            cancelled,
+            parentTaskId,
+            headers,
+            resourceStats,
+            null
+        );
+    }
+
+    public TaskInfo(
+        TaskId taskId,
+        String type,
+        String action,
+        String description,
+        Task.Status status,
+        long startTime,
+        long runningTimeNanos,
+        boolean cancellable,
+        boolean cancelled,
+        TaskId parentTaskId,
+        Map<String, String> headers,
+        TaskResourceStats resourceStats,
+        Long cancellationStartTime
     ) {
         if (cancellable == false && cancelled == true) {
             throw new IllegalArgumentException("task cannot be cancelled");
@@ -113,11 +155,14 @@ public TaskInfo(
         this.cancelled = cancelled;
         this.parentTaskId = parentTaskId;
         this.headers = headers;
+        this.resourceStats = resourceStats;
+        this.cancellationStartTime = cancellationStartTime;
     }
 
     /**
      * Read from a stream.
      */
+    @SuppressWarnings("unchecked")
     public TaskInfo(StreamInput in) throws IOException {
         taskId = TaskId.readFromStream(in);
         type = in.readString();
@@ -137,6 +182,16 @@ public TaskInfo(StreamInput in) throws IOException {
         }
         parentTaskId = TaskId.readFromStream(in);
         headers = in.readMap(StreamInput::readString, StreamInput::readString);
+        if (in.getVersion().onOrAfter(Version.V_2_1_0)) {
+            resourceStats = in.readOptionalWriteable(TaskResourceStats::new);
+        } else {
+            resourceStats = null;
+        }
+        if (in.getVersion().onOrAfter(Version.V_2_8_0)) {
+            cancellationStartTime = in.readOptionalLong();
+        } else {
+            cancellationStartTime = null;
+        }
     }
 
     @Override
@@ -154,6 +209,12 @@ public void writeTo(StreamOutput out) throws IOException {
         }
         parentTaskId.writeTo(out);
         out.writeMap(headers, StreamOutput::writeString, StreamOutput::writeString);
+        if (out.getVersion().onOrAfter(Version.V_2_1_0)) {
+            out.writeOptionalWriteable(resourceStats);
+        }
+        if (out.getVersion().onOrAfter(Version.V_2_8_0)) {
+            out.writeOptionalLong(cancellationStartTime);
+        }
     }
 
     public TaskId getTaskId() {
@@ -212,6 +273,10 @@ public boolean isCancelled() {
         return cancelled;
     }
 
+    public Long getCancellationStartTime() {
+        return cancellationStartTime;
+    }
+
     /**
      * Returns the parent task id
      */
@@ -226,6 +291,13 @@ public Map<String, String> getHeaders() {
         return headers;
     }
 
+    /**
+     * Returns the task resource information
+     */
+    public TaskResourceStats getResourceStats() {
+        return resourceStats;
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.field("node", taskId.getNodeId());
@@ -253,6 +325,14 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field(attribute.getKey(), attribute.getValue());
         }
         builder.endObject();
+        if (resourceStats != null) {
+            builder.startObject("resource_stats");
+            resourceStats.toXContent(builder, params);
+            builder.endObject();
+        }
+        if (cancellationStartTime != null) {
+            builder.humanReadableField("cancellation_time_millis", "cancellation_time", new TimeValue(cancellationStartTime));
+        }
         return builder;
     }
 
@@ -278,6 +358,9 @@ public static TaskInfo fromXContent(XContentParser parser) {
             // This might happen if we are reading an old version of task info
             headers = Collections.emptyMap();
         }
+        @SuppressWarnings("unchecked")
+        TaskResourceStats resourceStats = (TaskResourceStats) a[i++];
+        Long cancellationStartTime = (Long) a[i++];
         RawTaskStatus status = statusBytes == null ? null : new RawTaskStatus(statusBytes);
         TaskId parentTaskId = parentTaskIdString == null ? TaskId.EMPTY_TASK_ID : new TaskId(parentTaskIdString);
         return new TaskInfo(
@@ -291,7 +374,9 @@ public static TaskInfo fromXContent(XContentParser parser) {
             cancellable,
             cancelled,
             parentTaskId,
-            headers
+            headers,
+            resourceStats,
+            cancellationStartTime
         );
     });
     static {
@@ -309,11 +394,13 @@ public static TaskInfo fromXContent(XContentParser parser) {
         PARSER.declareBoolean(optionalConstructorArg(), new ParseField("cancelled"));
         PARSER.declareString(optionalConstructorArg(), new ParseField("parent_task_id"));
         PARSER.declareObject(optionalConstructorArg(), (p, c) -> p.mapStrings(), new ParseField("headers"));
+        PARSER.declareObject(optionalConstructorArg(), (p, c) -> TaskResourceStats.fromXContent(p), new ParseField("resource_stats"));
+        PARSER.declareLong(optionalConstructorArg(), new ParseField("cancellation_time_millis"));
     }
 
     @Override
     public String toString() {
-        return Strings.toString(this, true, true);
+        return Strings.toString(MediaTypeRegistry.JSON, this, true, true);
     }
 
     // Implements equals and hashCode for testing
@@ -333,7 +420,9 @@ public boolean equals(Object obj) {
             && Objects.equals(cancellable, other.cancellable)
             && Objects.equals(cancelled, other.cancelled)
             && Objects.equals(status, other.status)
-            && Objects.equals(headers, other.headers);
+            && Objects.equals(headers, other.headers)
+            && Objects.equals(resourceStats, other.resourceStats)
+            && Objects.equals(cancellationStartTime, other.cancellationStartTime);
     }
 
     @Override
@@ -349,7 +438,9 @@ public int hashCode() {
             cancellable,
             cancelled,
             status,
-            headers
+            headers,
+            resourceStats,
+            cancellationStartTime
         );
     }
 }
diff --git a/server/src/main/java/org/opensearch/tasks/TaskListener.java b/server/src/main/java/org/opensearch/tasks/TaskListener.java
index e5581ad08d226..97df8eacee584 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskListener.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskListener.java
@@ -34,6 +34,8 @@
 
 /**
  * Listener for Task success or failure.
+ *
+ * @opensearch.internal
  */
 public interface TaskListener<Response> {
     /**
diff --git a/server/src/main/java/org/opensearch/tasks/TaskManager.java b/server/src/main/java/org/opensearch/tasks/TaskManager.java
index 1f6169768f245..a49968ab85e89 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskManager.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskManager.java
@@ -32,31 +32,34 @@
 
 package org.opensearch.tasks;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.ObjectIntMap;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.ConcurrentMapLong;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TcpChannel;
 
@@ -65,6 +68,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -74,14 +78,16 @@
 import java.util.concurrent.Semaphore;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Consumer;
 import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
 
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.http.HttpTransportSettings.SETTING_HTTP_MAX_HEADER_SIZE;
 
 /**
  * Task Manager service for keeping track of currently running tasks on the nodes
+ *
+ * @opensearch.internal
  */
 public class TaskManager implements ClusterStateApplier {
 
@@ -89,7 +95,18 @@ public class TaskManager implements ClusterStateApplier {
 
     private static final TimeValue WAIT_FOR_COMPLETION_POLL = timeValueMillis(100);
 
-    /** Rest headers that are copied to the task */
+    public static final String TASK_RESOURCE_CONSUMERS_ATTRIBUTES = "task_resource_consumers.enabled";
+
+    public static final Setting<Boolean> TASK_RESOURCE_CONSUMERS_ENABLED = Setting.boolSetting(
+        TASK_RESOURCE_CONSUMERS_ATTRIBUTES,
+        false,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    /**
+     * Rest headers that are copied to the task
+     */
     private final List<String> taskHeaders;
     private final ThreadPool threadPool;
 
@@ -103,6 +120,7 @@ public class TaskManager implements ClusterStateApplier {
     private final Map<TaskId, String> banedParents = new ConcurrentHashMap<>();
 
     private TaskResultsService taskResultsService;
+    private final SetOnce<TaskResourceTrackingService> taskResourceTrackingService = new SetOnce<>();
 
     private volatile DiscoveryNodes lastDiscoveryNodes = DiscoveryNodes.EMPTY_NODES;
 
@@ -110,10 +128,44 @@ public class TaskManager implements ClusterStateApplier {
     private final Map<TcpChannel, ChannelPendingTaskTracker> channelPendingTaskTrackers = ConcurrentCollections.newConcurrentMap();
     private final SetOnce<TaskCancellationService> cancellationService = new SetOnce<>();
 
+    private volatile boolean taskResourceConsumersEnabled;
+    private final Set<Consumer<Task>> taskResourceConsumer;
+    private final List<TaskEventListeners> taskEventListeners = new ArrayList<>();
+
+    public static TaskManager createTaskManagerWithClusterSettings(
+        Settings settings,
+        ClusterSettings clusterSettings,
+        ThreadPool threadPool,
+        Set<String> taskHeaders
+    ) {
+        final TaskManager taskManager = new TaskManager(settings, threadPool, taskHeaders);
+        clusterSettings.addSettingsUpdateConsumer(TASK_RESOURCE_CONSUMERS_ENABLED, taskManager::setTaskResourceConsumersEnabled);
+        return taskManager;
+    }
+
     public TaskManager(Settings settings, ThreadPool threadPool, Set<String> taskHeaders) {
         this.threadPool = threadPool;
         this.taskHeaders = new ArrayList<>(taskHeaders);
         this.maxHeaderSize = SETTING_HTTP_MAX_HEADER_SIZE.get(settings);
+        this.taskResourceConsumersEnabled = TASK_RESOURCE_CONSUMERS_ENABLED.get(settings);
+        taskResourceConsumer = new HashSet<>();
+    }
+
+    /**
+     * Listener that gets invoked during an event such as task cancellation/completion.
+     */
+    public interface TaskEventListeners {
+        default void onTaskCancelled(CancellableTask task) {}
+
+        default void onTaskCompleted(Task task) {}
+    }
+
+    public void addTaskEventListeners(TaskEventListeners taskEventListeners) {
+        this.taskEventListeners.add(taskEventListeners);
+    }
+
+    public void registerTaskResourceConsumer(Consumer<Task> consumer) {
+        taskResourceConsumer.add(consumer);
     }
 
     public void setTaskResultsService(TaskResultsService taskResultsService) {
@@ -125,6 +177,14 @@ public void setTaskCancellationService(TaskCancellationService taskCancellationS
         this.cancellationService.set(taskCancellationService);
     }
 
+    public void setTaskResourceTrackingService(TaskResourceTrackingService taskResourceTrackingService) {
+        this.taskResourceTrackingService.set(taskResourceTrackingService);
+    }
+
+    public void setTaskResourceConsumersEnabled(boolean taskResourceConsumersEnabled) {
+        this.taskResourceConsumersEnabled = taskResourceConsumersEnabled;
+    }
+
     /**
      * Registers a task without parent task
      */
@@ -150,6 +210,30 @@ public Task register(String type, String action, TaskAwareRequest request) {
             logger.trace("register {} [{}] [{}] [{}]", task.getId(), type, action, task.getDescription());
         }
 
+        if (task.supportsResourceTracking()) {
+            boolean success = task.addResourceTrackingCompletionListener(new NotifyOnceListener<>() {
+                @Override
+                protected void innerOnResponse(Task task) {
+                    // Stop tracking the task once the last thread has been marked inactive.
+                    if (taskResourceTrackingService.get() != null && task.supportsResourceTracking()) {
+                        taskResourceTrackingService.get().stopTracking(task);
+                    }
+                }
+
+                @Override
+                protected void innerOnFailure(Exception e) {
+                    ExceptionsHelper.reThrowIfNotNull(e);
+                }
+            });
+
+            if (success == false) {
+                logger.debug(
+                    "failed to register a completion listener as task resource tracking has already completed [taskId={}]",
+                    task.getId()
+                );
+            }
+        }
+
         if (task instanceof CancellableTask) {
             registerCancellableTask(task);
         } else {
@@ -189,6 +273,17 @@ private void registerCancellableTask(Task task) {
      */
     public void cancel(CancellableTask task, String reason, Runnable listener) {
         CancellableTaskHolder holder = cancellableTasks.get(task.getId());
+        List<Exception> exceptions = new ArrayList<>();
+        for (TaskEventListeners taskEventListener : taskEventListeners) {
+            try {
+                taskEventListener.onTaskCancelled(task);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+        // Throwing exception in case any of the cancellation listener results into exception.
+        // Should we just swallow such exceptions?
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
         if (holder != null) {
             logger.trace("cancelling task with id {}", task.getId());
             holder.cancel(reason, listener);
@@ -202,6 +297,29 @@ public void cancel(CancellableTask task, String reason, Runnable listener) {
      */
     public Task unregister(Task task) {
         logger.trace("unregister task for id: {}", task.getId());
+        List<Exception> exceptions = new ArrayList<>();
+        for (TaskEventListeners taskEventListener : taskEventListeners) {
+            try {
+                taskEventListener.onTaskCompleted(task);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+
+        // Decrement the task's self-thread as part of unregistration.
+        task.decrementResourceTrackingThreads();
+
+        if (taskResourceConsumersEnabled) {
+            for (Consumer<Task> taskConsumer : taskResourceConsumer) {
+                try {
+                    taskConsumer.accept(task);
+                } catch (Exception e) {
+                    logger.error("error encountered when updating the consumer", e);
+                }
+            }
+        }
+
         if (task instanceof CancellableTask) {
             CancellableTaskHolder holder = cancellableTasks.remove(task.getId());
             if (holder != null) {
@@ -248,7 +366,7 @@ public <Response extends ActionResponse> void storeResult(Task task, Exception e
         }
         final TaskResult taskResult;
         try {
-            taskResult = task.result(localNode, error);
+            taskResult = task.result(localNode.getId(), error);
         } catch (IOException ex) {
             logger.warn(() -> new ParameterizedMessage("couldn't store error {}", ExceptionsHelper.detailedMessage(error)), ex);
             listener.onFailure(ex);
@@ -281,7 +399,7 @@ public <Response extends ActionResponse> void storeResult(Task task, Response re
         }
         final TaskResult taskResult;
         try {
-            taskResult = task.result(localNode, response);
+            taskResult = task.result(localNode.getId(), response);
         } catch (IOException ex) {
             logger.warn(() -> new ParameterizedMessage("couldn't store response {}", response), ex);
             listener.onFailure(ex);
@@ -361,6 +479,7 @@ public int getBanCount() {
      * Bans all tasks with the specified parent task from execution, cancels all tasks that are currently executing.
      * <p>
      * This method is called when a parent task that has children is cancelled.
+     *
      * @return a list of pending cancellable child tasks
      */
     public List<CancellableTask> setBan(TaskId parentTaskId, String reason) {
@@ -448,11 +567,23 @@ public void waitForTaskCompletion(Task task, long untilInNanos) {
         throw new OpenSearchTimeoutException("Timed out waiting for completion of [{}]", task);
     }
 
+    /**
+     * Takes actions when a task is registered and its execution starts
+     *
+     * @param task getting executed.
+     * @return AutoCloseable to free up resources (clean up thread context) when task execution block returns
+     */
+    public ThreadContext.StoredContext taskExecutionStarted(Task task) {
+        if (taskResourceTrackingService.get() == null) return () -> {};
+
+        return taskResourceTrackingService.get().startTracking(task);
+    }
+
     private static class CancellableTaskHolder {
         private final CancellableTask task;
         private boolean finished = false;
         private List<Runnable> cancellationListeners = null;
-        private ObjectIntMap<DiscoveryNode> childTasksPerNode = null;
+        private Map<DiscoveryNode, Integer> childTasksPerNode = null;
         private boolean banChildren = false;
         private List<Runnable> childTaskCompletedListeners = null;
 
@@ -534,15 +665,15 @@ synchronized void registerChildNode(DiscoveryNode node) {
                 throw new TaskCancelledException("The parent task was cancelled, shouldn't start any child tasks");
             }
             if (childTasksPerNode == null) {
-                childTasksPerNode = new ObjectIntHashMap<>();
+                childTasksPerNode = new HashMap<>();
             }
-            childTasksPerNode.addTo(node, 1);
+            childTasksPerNode.merge(node, 1, Integer::sum);
         }
 
         void unregisterChildNode(DiscoveryNode node) {
             final List<Runnable> listeners;
             synchronized (this) {
-                if (childTasksPerNode.addTo(node, -1) == 0) {
+                if (childTasksPerNode.merge(node, -1, Integer::sum) == 0) {
                     childTasksPerNode.remove(node);
                 }
                 if (childTasksPerNode.isEmpty() && this.childTaskCompletedListeners != null) {
@@ -563,9 +694,7 @@ Set<DiscoveryNode> startBan(Runnable onChildTasksCompleted) {
                 if (childTasksPerNode == null) {
                     pendingChildNodes = Collections.emptySet();
                 } else {
-                    pendingChildNodes = StreamSupport.stream(childTasksPerNode.spliterator(), false)
-                        .map(e -> e.key)
-                        .collect(Collectors.toSet());
+                    pendingChildNodes = Set.copyOf(childTasksPerNode.keySet());
                 }
                 if (pendingChildNodes.isEmpty()) {
                     assert childTaskCompletedListeners == null;
diff --git a/server/src/main/java/org/opensearch/tasks/TaskResourceTrackingService.java b/server/src/main/java/org/opensearch/tasks/TaskResourceTrackingService.java
new file mode 100644
index 0000000000000..f32559f6314c0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskResourceTrackingService.java
@@ -0,0 +1,274 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import com.sun.management.ThreadMXBean;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.common.util.concurrent.ConcurrentMapLong;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageMetric;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
+import org.opensearch.threadpool.RunnableTaskExecutionListener;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.lang.management.ManagementFactory;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.core.tasks.resourcetracker.ResourceStatsType.WORKER_STATS;
+
+/**
+ * Service that helps track resource usage of tasks running on a node.
+ */
+@SuppressForbidden(reason = "ThreadMXBean#getThreadAllocatedBytes")
+public class TaskResourceTrackingService implements RunnableTaskExecutionListener {
+
+    private static final Logger logger = LogManager.getLogger(TaskManager.class);
+
+    public static final Setting<Boolean> TASK_RESOURCE_TRACKING_ENABLED = Setting.boolSetting(
+        "task_resource_tracking.enabled",
+        true,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+    public static final String TASK_ID = "TASK_ID";
+
+    private static final ThreadMXBean threadMXBean = (ThreadMXBean) ManagementFactory.getThreadMXBean();
+
+    private final ConcurrentMapLong<Task> resourceAwareTasks = ConcurrentCollections.newConcurrentMapLongWithAggressiveConcurrency();
+    private final List<TaskCompletionListener> taskCompletionListeners = new ArrayList<>();
+    private final ThreadPool threadPool;
+    private volatile boolean taskResourceTrackingEnabled;
+
+    @Inject
+    public TaskResourceTrackingService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
+        this.taskResourceTrackingEnabled = TASK_RESOURCE_TRACKING_ENABLED.get(settings);
+        this.threadPool = threadPool;
+        clusterSettings.addSettingsUpdateConsumer(TASK_RESOURCE_TRACKING_ENABLED, this::setTaskResourceTrackingEnabled);
+    }
+
+    public void setTaskResourceTrackingEnabled(boolean taskResourceTrackingEnabled) {
+        this.taskResourceTrackingEnabled = taskResourceTrackingEnabled;
+    }
+
+    public boolean isTaskResourceTrackingEnabled() {
+        return taskResourceTrackingEnabled;
+    }
+
+    public boolean isTaskResourceTrackingSupported() {
+        return threadMXBean.isThreadAllocatedMemorySupported() && threadMXBean.isThreadAllocatedMemoryEnabled();
+    }
+
+    /**
+     * Executes logic only if task supports resource tracking and resource tracking setting is enabled.
+     * <p>
+     * 1. Starts tracking the task in map of resourceAwareTasks.
+     * 2. Adds Task Id in thread context to make sure it's available while task is processed across multiple threads.
+     *
+     * @param task for which resources needs to be tracked
+     * @return Autocloseable stored context to restore ThreadContext to the state before this method changed it.
+     */
+    public ThreadContext.StoredContext startTracking(Task task) {
+        if (task.supportsResourceTracking() == false
+            || isTaskResourceTrackingEnabled() == false
+            || isTaskResourceTrackingSupported() == false) {
+            return () -> {};
+        }
+
+        logger.debug("Starting resource tracking for task: {}", task.getId());
+        resourceAwareTasks.put(task.getId(), task);
+        return addTaskIdToThreadContext(task);
+    }
+
+    /**
+     * Stops tracking task registered earlier for tracking.
+     * <p>
+     * It doesn't have feature enabled check to avoid any issues if setting was disable while the task was in progress.
+     * <p>
+     * It's also responsible to stop tracking the current thread's resources against this task if not already done.
+     * This happens when the thread executing the request logic itself calls the unregister method. So in this case unregister
+     * happens before runnable finishes.
+     *
+     * @param task task which has finished and doesn't need resource tracking.
+     */
+    public void stopTracking(Task task) {
+        logger.debug("Stopping resource tracking for task: {}", task.getId());
+        try {
+            if (isCurrentThreadWorkingOnTask(task)) {
+                taskExecutionFinishedOnThread(task.getId(), Thread.currentThread().getId());
+            }
+        } catch (Exception e) {
+            logger.warn("Failed while trying to mark the task execution on current thread completed.", e);
+            assert false;
+        } finally {
+            resourceAwareTasks.remove(task.getId());
+        }
+
+        List<Exception> exceptions = new ArrayList<>();
+        for (TaskCompletionListener listener : taskCompletionListeners) {
+            try {
+                listener.onTaskCompleted(task);
+            } catch (Exception e) {
+                exceptions.add(e);
+            }
+        }
+        ExceptionsHelper.maybeThrowRuntimeAndSuppress(exceptions);
+    }
+
+    /**
+     * Refreshes the resource stats for the tasks provided by looking into which threads are actively working on these
+     * and how much resources these have consumed till now.
+     *
+     * @param tasks for which resource stats needs to be refreshed.
+     */
+    public void refreshResourceStats(Task... tasks) {
+        if (isTaskResourceTrackingEnabled() == false || isTaskResourceTrackingSupported() == false) {
+            return;
+        }
+
+        for (Task task : tasks) {
+            if (task.supportsResourceTracking() && resourceAwareTasks.containsKey(task.getId())) {
+                refreshResourceStats(task);
+            }
+        }
+    }
+
+    private void refreshResourceStats(Task resourceAwareTask) {
+        try {
+            logger.debug("Refreshing resource stats for Task: {}", resourceAwareTask.getId());
+            List<Long> threadsWorkingOnTask = getThreadsWorkingOnTask(resourceAwareTask);
+            threadsWorkingOnTask.forEach(
+                threadId -> resourceAwareTask.updateThreadResourceStats(threadId, WORKER_STATS, getResourceUsageMetricsForThread(threadId))
+            );
+        } catch (IllegalStateException e) {
+            logger.debug("Resource stats already updated.");
+        }
+
+    }
+
+    /**
+     * Called when a thread starts working on a task's runnable.
+     *
+     * @param taskId   of the task for which runnable is starting
+     * @param threadId of the thread which will be executing the runnable and we need to check resource usage for this
+     *                 thread
+     */
+    @Override
+    public void taskExecutionStartedOnThread(long taskId, long threadId) {
+        try {
+            final Task task = resourceAwareTasks.get(taskId);
+            if (task != null) {
+                logger.debug("Task execution started on thread. Task: {}, Thread: {}", taskId, threadId);
+                task.startThreadResourceTracking(threadId, WORKER_STATS, getResourceUsageMetricsForThread(threadId));
+            }
+        } catch (Exception e) {
+            logger.warn(new ParameterizedMessage("Failed to mark thread execution started for task: [{}]", taskId), e);
+            assert false;
+        }
+
+    }
+
+    /**
+     * Called when a thread finishes working on a task's runnable.
+     *
+     * @param taskId   of the task for which runnable is complete
+     * @param threadId of the thread which executed the runnable and we need to check resource usage for this thread
+     */
+    @Override
+    public void taskExecutionFinishedOnThread(long taskId, long threadId) {
+        try {
+            final Task task = resourceAwareTasks.get(taskId);
+            if (task != null) {
+                logger.debug("Task execution finished on thread. Task: {}, Thread: {}", taskId, threadId);
+                task.stopThreadResourceTracking(threadId, WORKER_STATS, getResourceUsageMetricsForThread(threadId));
+            }
+        } catch (Exception e) {
+            logger.warn(new ParameterizedMessage("Failed to mark thread execution finished for task: [{}]", taskId), e);
+            assert false;
+        }
+    }
+
+    public Map<Long, Task> getResourceAwareTasks() {
+        return Collections.unmodifiableMap(resourceAwareTasks);
+    }
+
+    private ResourceUsageMetric[] getResourceUsageMetricsForThread(long threadId) {
+        ResourceUsageMetric currentMemoryUsage = new ResourceUsageMetric(
+            ResourceStats.MEMORY,
+            threadMXBean.getThreadAllocatedBytes(threadId)
+        );
+        ResourceUsageMetric currentCPUUsage = new ResourceUsageMetric(ResourceStats.CPU, threadMXBean.getThreadCpuTime(threadId));
+        return new ResourceUsageMetric[] { currentMemoryUsage, currentCPUUsage };
+    }
+
+    private boolean isCurrentThreadWorkingOnTask(Task task) {
+        long threadId = Thread.currentThread().getId();
+        List<ThreadResourceInfo> threadResourceInfos = task.getResourceStats().getOrDefault(threadId, Collections.emptyList());
+
+        for (ThreadResourceInfo threadResourceInfo : threadResourceInfos) {
+            if (threadResourceInfo.isActive()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private List<Long> getThreadsWorkingOnTask(Task task) {
+        List<Long> activeThreads = new ArrayList<>();
+        for (List<ThreadResourceInfo> threadResourceInfos : task.getResourceStats().values()) {
+            for (ThreadResourceInfo threadResourceInfo : threadResourceInfos) {
+                if (threadResourceInfo.isActive()) {
+                    activeThreads.add(threadResourceInfo.getThreadId());
+                }
+            }
+        }
+        return activeThreads;
+    }
+
+    /**
+     * Adds Task Id in the ThreadContext.
+     * <p>
+     * Stashes the existing ThreadContext and preserves all the existing ThreadContext's data in the new ThreadContext
+     * as well.
+     *
+     * @param task for which Task Id needs to be added in ThreadContext.
+     * @return StoredContext reference to restore the ThreadContext from which we created a new one.
+     * Caller can call context.restore() to get the existing ThreadContext back.
+     */
+    private ThreadContext.StoredContext addTaskIdToThreadContext(Task task) {
+        ThreadContext threadContext = threadPool.getThreadContext();
+        ThreadContext.StoredContext storedContext = threadContext.newStoredContext(true, Collections.singletonList(TASK_ID));
+        threadContext.putTransient(TASK_ID, task.getId());
+        return storedContext;
+    }
+
+    /**
+     * Listener that gets invoked when a task execution completes.
+     */
+    public interface TaskCompletionListener {
+        void onTaskCompleted(Task task);
+    }
+
+    public void addTaskCompletionListener(TaskCompletionListener listener) {
+        this.taskCompletionListeners.add(listener);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/TaskResult.java b/server/src/main/java/org/opensearch/tasks/TaskResult.java
index 8e10b2eaa1cdf..f42e833f5ca08 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskResult.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskResult.java
@@ -34,19 +34,19 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.client.Requests;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.InstantiatingObjectParser;
-import org.opensearch.common.xcontent.ObjectParserHelper;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.InstantiatingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ObjectParserHelper;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
 
 import java.io.IOException;
 import java.util.Map;
@@ -54,13 +54,16 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Objects.requireNonNull;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.common.xcontent.XContentHelper.convertToMap;
+import static org.opensearch.common.xcontent.XContentHelper.writeRawField;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 /**
  * Information about a running task or a task that stored its result. Running tasks just have a {@link #getTask()} while
  * tasks with stored result will have either a {@link #getError()} or {@link #getResponse()}.
+ *
+ * @opensearch.internal
  */
 public final class TaskResult implements Writeable, ToXContentObject {
     private final boolean completed;
@@ -179,10 +182,10 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
         task.toXContent(builder, params);
         builder.endObject();
         if (error != null) {
-            XContentHelper.writeRawField("error", error, builder, params);
+            writeRawField("error", error, builder, params);
         }
         if (response != null) {
-            XContentHelper.writeRawField("response", response, builder, params);
+            writeRawField("response", response, builder, params);
         }
         return builder;
     }
@@ -205,7 +208,7 @@ public XContentBuilder innerToXContent(XContentBuilder builder, Params params) t
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(MediaTypeRegistry.JSON, this);
     }
 
     // Implements equals and hashcode for testing
@@ -235,7 +238,7 @@ public int hashCode() {
     }
 
     private static BytesReference toXContent(Exception error) throws IOException {
-        try (XContentBuilder builder = XContentFactory.contentBuilder(Requests.INDEX_CONTENT_TYPE)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(Requests.INDEX_CONTENT_TYPE)) {
             builder.startObject();
             OpenSearchException.generateThrowableXContent(builder, ToXContent.EMPTY_PARAMS, error);
             builder.endObject();
diff --git a/server/src/main/java/org/opensearch/tasks/TaskResultsService.java b/server/src/main/java/org/opensearch/tasks/TaskResultsService.java
index e22793e057c6a..d1ee04bd5cb25 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskResultsService.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskResultsService.java
@@ -37,7 +37,6 @@
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.ResourceAlreadyExistsException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.bulk.BackoffPolicy;
@@ -53,12 +52,12 @@
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.common.util.io.Streams;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.ByteArrayOutputStream;
@@ -73,6 +72,8 @@
 
 /**
  * Service that can store task results.
+ *
+ * @opensearch.internal
  */
 public class TaskResultsService {
 
@@ -84,7 +85,7 @@ public class TaskResultsService {
 
     public static final String TASK_RESULT_MAPPING_VERSION_META_FIELD = "version";
 
-    public static final int TASK_RESULT_MAPPING_VERSION = 3; // must match version in task-index-mapping.json
+    public static final int TASK_RESULT_MAPPING_VERSION = 4; // must match version in task-index-mapping.json
 
     /**
      * The backoff policy to use when saving a task result fails. The total wait
@@ -144,7 +145,7 @@ public void onFailure(Exception e) {
                 client.admin()
                     .indices()
                     .preparePutMapping(TASK_INDEX)
-                    .setSource(taskResultIndexMapping(), XContentType.JSON)
+                    .setSource(taskResultIndexMapping(), MediaTypeRegistry.JSON)
                     .execute(ActionListener.delegateFailure(listener, (l, r) -> doStoreResult(taskResult, listener)));
             } else {
                 doStoreResult(taskResult, listener);
@@ -167,7 +168,7 @@ private int getTaskResultMappingVersion(IndexMetadata metadata) {
 
     private void doStoreResult(TaskResult taskResult, ActionListener<Void> listener) {
         IndexRequestBuilder index = client.prepareIndex(TASK_INDEX).setId(taskResult.getTask().getTaskId().toString());
-        try (XContentBuilder builder = XContentFactory.contentBuilder(Requests.INDEX_CONTENT_TYPE)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(Requests.INDEX_CONTENT_TYPE)) {
             taskResult.toXContent(builder, ToXContent.EMPTY_PARAMS);
             index.setSource(builder);
         } catch (IOException e) {
diff --git a/server/src/main/java/org/opensearch/tasks/TaskThreadContextStatePropagator.java b/server/src/main/java/org/opensearch/tasks/TaskThreadContextStatePropagator.java
new file mode 100644
index 0000000000000..ed111b34f048f
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/TaskThreadContextStatePropagator.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.common.util.concurrent.ThreadContextStatePropagator;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.tasks.TaskResourceTrackingService.TASK_ID;
+
+/**
+ * Propagates TASK_ID across thread contexts
+ */
+public class TaskThreadContextStatePropagator implements ThreadContextStatePropagator {
+    @Override
+    public Map<String, Object> transients(Map<String, Object> source) {
+        final Map<String, Object> transients = new HashMap<>();
+
+        if (source.containsKey(TASK_ID)) {
+            transients.put(TASK_ID, source.get(TASK_ID));
+        }
+
+        return transients;
+    }
+
+    @Override
+    public Map<String, String> headers(Map<String, Object> source) {
+        return Collections.emptyMap();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessage.java b/server/src/main/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessage.java
new file mode 100644
index 0000000000000..1755db3ab4ae8
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessage.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks.consumer;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.logging.OpenSearchLogMessage;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Search shard task information that will be extracted from Task and converted into
+ * format that will be logged
+ *
+ * @opensearch.internal
+ */
+public final class SearchShardTaskDetailsLogMessage extends OpenSearchLogMessage {
+    SearchShardTaskDetailsLogMessage(SearchShardTask task) {
+        super(prepareMap(task), message(task));
+    }
+
+    private static Map<String, Object> prepareMap(SearchShardTask task) {
+        Map<String, Object> messageFields = new HashMap<>();
+        messageFields.put("taskId", task.getId());
+        messageFields.put("type", task.getType());
+        messageFields.put("action", task.getAction());
+        messageFields.put("description", task.getDescription());
+        messageFields.put("start_time_millis", task.getStartTime());
+        messageFields.put("parentTaskId", task.getParentTaskId());
+        messageFields.put("resource_stats", task.getResourceStats());
+        messageFields.put("metadata", task.getTaskMetadata());
+        return messageFields;
+    }
+
+    // Message will be used in plaintext logs
+    private static String message(SearchShardTask task) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("taskId:[")
+            .append(task.getId())
+            .append("], ")
+            .append("type:[")
+            .append(task.getType())
+            .append("], ")
+            .append("action:[")
+            .append(task.getAction())
+            .append("], ")
+            .append("description:[")
+            .append(task.getDescription())
+            .append("], ")
+            .append("start_time_millis:[")
+            .append(task.getStartTime())
+            .append("], ")
+            .append("resource_stats:[")
+            .append(task.getResourceStats())
+            .append("], ")
+            .append("metadata:[")
+            .append(task.getTaskMetadata())
+            .append("]");
+        return sb.toString();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/consumer/TopNSearchTasksLogger.java b/server/src/main/java/org/opensearch/tasks/consumer/TopNSearchTasksLogger.java
new file mode 100644
index 0000000000000..6f977481852ec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/consumer/TopNSearchTasksLogger.java
@@ -0,0 +1,115 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks.consumer;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.tasks.Task;
+
+import java.util.Comparator;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.function.Consumer;
+
+/**
+ * A simple listener that logs resource information of high memory consuming search tasks
+ *
+ * @opensearch.internal
+ */
+public class TopNSearchTasksLogger implements Consumer<Task> {
+    public static final String TASK_DETAILS_LOG_PREFIX = "task.detailslog";
+    private static final String LOG_TOP_QUERIES_SIZE = "cluster.task.consumers.top_n.size";
+    private static final String LOG_TOP_QUERIES_FREQUENCY = "cluster.task.consumers.top_n.frequency";
+
+    private static final Logger SEARCH_TASK_DETAILS_LOGGER = LogManager.getLogger(TASK_DETAILS_LOG_PREFIX + ".search");
+
+    // number of memory expensive search tasks that are logged
+    public static final Setting<Integer> LOG_TOP_QUERIES_SIZE_SETTING = Setting.intSetting(
+        LOG_TOP_QUERIES_SIZE,
+        10,
+        1,
+        100,
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    // frequency in which memory expensive search tasks are logged
+    public static final Setting<TimeValue> LOG_TOP_QUERIES_FREQUENCY_SETTING = Setting.timeSetting(
+        LOG_TOP_QUERIES_FREQUENCY,
+        TimeValue.timeValueSeconds(60L),
+        TimeValue.timeValueSeconds(60L),
+        Setting.Property.Dynamic,
+        Setting.Property.NodeScope
+    );
+
+    private volatile int topQueriesSize;
+    private volatile long topQueriesLogFrequencyInNanos;
+    private final Queue<Tuple<Long, SearchShardTask>> topQueries;
+    private long lastReportedTimeInNanos = System.nanoTime();
+
+    public TopNSearchTasksLogger(Settings settings, ClusterSettings clusterSettings) {
+        this.topQueriesSize = LOG_TOP_QUERIES_SIZE_SETTING.get(settings);
+        this.topQueriesLogFrequencyInNanos = LOG_TOP_QUERIES_FREQUENCY_SETTING.get(settings).getNanos();
+        this.topQueries = new PriorityQueue<>(topQueriesSize, Comparator.comparingLong(Tuple::v1));
+        clusterSettings.addSettingsUpdateConsumer(LOG_TOP_QUERIES_SIZE_SETTING, this::setLogTopQueriesSize);
+        clusterSettings.addSettingsUpdateConsumer(LOG_TOP_QUERIES_FREQUENCY_SETTING, this::setTopQueriesLogFrequencyInNanos);
+    }
+
+    /**
+     * Called when task is unregistered and task has resource stats present.
+     */
+    @Override
+    public void accept(Task task) {
+        if (task instanceof SearchShardTask) {
+            recordSearchTask((SearchShardTask) task);
+        }
+    }
+
+    private synchronized void recordSearchTask(SearchShardTask searchTask) {
+        final long memory_in_bytes = searchTask.getTotalResourceUtilization(ResourceStats.MEMORY);
+        if (System.nanoTime() - lastReportedTimeInNanos >= topQueriesLogFrequencyInNanos) {
+            publishTopNEvents();
+            lastReportedTimeInNanos = System.nanoTime();
+        }
+        int topQSize = topQueriesSize;
+        if (topQueries.size() >= topQSize && topQueries.peek().v1() < memory_in_bytes) {
+            // evict the element
+            topQueries.poll();
+        }
+        if (topQueries.size() < topQSize) {
+            topQueries.offer(new Tuple<>(memory_in_bytes, searchTask));
+        }
+    }
+
+    private void publishTopNEvents() {
+        logTopResourceConsumingQueries();
+        topQueries.clear();
+    }
+
+    private void logTopResourceConsumingQueries() {
+        for (Tuple<Long, SearchShardTask> topQuery : topQueries) {
+            SEARCH_TASK_DETAILS_LOGGER.info(new SearchShardTaskDetailsLogMessage(topQuery.v2()));
+        }
+    }
+
+    private void setLogTopQueriesSize(int topQueriesSize) {
+        this.topQueriesSize = topQueriesSize;
+    }
+
+    void setTopQueriesLogFrequencyInNanos(TimeValue timeValue) {
+        this.topQueriesLogFrequencyInNanos = timeValue.getNanos();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/tasks/consumer/package-info.java b/server/src/main/java/org/opensearch/tasks/consumer/package-info.java
new file mode 100644
index 0000000000000..40219a1cead5b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/tasks/consumer/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Support for adding consumers to consume task related information.
+ */
+package org.opensearch.tasks.consumer;
diff --git a/server/src/main/java/org/opensearch/telemetry/TelemetryModule.java b/server/src/main/java/org/opensearch/telemetry/TelemetryModule.java
new file mode 100644
index 0000000000000..604c111b0720c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/TelemetryModule.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.plugins.TelemetryPlugin;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * A module for loading classes for telemetry
+ *
+ * @opensearch.internal
+ */
+public class TelemetryModule {
+
+    private Telemetry telemetry;
+
+    public TelemetryModule(List<TelemetryPlugin> telemetryPlugins, TelemetrySettings telemetrySettings) {
+
+        for (TelemetryPlugin telemetryPlugin : telemetryPlugins) {
+            Optional<Telemetry> telemetry = telemetryPlugin.getTelemetry(telemetrySettings);
+            if (telemetry.isPresent()) {
+                registerTelemetry(telemetry.get());
+            }
+        }
+    }
+
+    public Optional<Telemetry> getTelemetry() {
+        return Optional.ofNullable(telemetry);
+    }
+
+    private void registerTelemetry(Telemetry factory) {
+        if (telemetry == null) {
+            telemetry = factory;
+        } else {
+            throw new IllegalArgumentException("Cannot register more than one telemetry");
+        }
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java b/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java
new file mode 100644
index 0000000000000..edb20cfa9dfc5
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java
@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+
+/**
+ * Wrapper class to encapsulate tracing related settings
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public class TelemetrySettings {
+    public static final Setting<Boolean> TRACER_ENABLED_SETTING = Setting.boolSetting(
+        "telemetry.tracer.enabled",
+        false,
+        Setting.Property.NodeScope,
+        Setting.Property.Dynamic
+    );
+
+    /**
+     * Probability of sampler
+     */
+    public static final Setting<Double> TRACER_SAMPLER_PROBABILITY = Setting.doubleSetting(
+        "telemetry.tracer.sampler.probability",
+        0.01d,
+        0.00d,
+        1.00d,
+        Setting.Property.NodeScope,
+        Setting.Property.Dynamic
+    );
+
+    /**
+     * metrics publish interval in seconds.
+     */
+    public static final Setting<TimeValue> METRICS_PUBLISH_INTERVAL_SETTING = Setting.timeSetting(
+        "telemetry.otel.metrics.publish.interval",
+        TimeValue.timeValueSeconds(60),
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+
+    private volatile boolean tracingEnabled;
+    private volatile double samplingProbability;
+
+    public TelemetrySettings(Settings settings, ClusterSettings clusterSettings) {
+        this.tracingEnabled = TRACER_ENABLED_SETTING.get(settings);
+        this.samplingProbability = TRACER_SAMPLER_PROBABILITY.get(settings);
+
+        clusterSettings.addSettingsUpdateConsumer(TRACER_ENABLED_SETTING, this::setTracingEnabled);
+        clusterSettings.addSettingsUpdateConsumer(TRACER_SAMPLER_PROBABILITY, this::setSamplingProbability);
+    }
+
+    public void setTracingEnabled(boolean tracingEnabled) {
+        this.tracingEnabled = tracingEnabled;
+    }
+
+    public boolean isTracingEnabled() {
+        return tracingEnabled;
+    }
+
+    /**
+     * Set sampling ratio
+     * @param samplingProbability double
+     */
+    public void setSamplingProbability(double samplingProbability) {
+        this.samplingProbability = samplingProbability;
+    }
+
+    /**
+     * Get sampling ratio
+     */
+    public double getSamplingProbability() {
+        return samplingProbability;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistryFactory.java b/server/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistryFactory.java
new file mode 100644
index 0000000000000..c7e2229c18437
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/metrics/MetricsRegistryFactory.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.metrics.noop.NoopMetricsRegistry;
+import org.opensearch.telemetry.tracing.Tracer;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Optional;
+
+/**
+ * {@link MetricsRegistryFactory} represents a single global class that is used to access {@link MetricsRegistry}s.
+ * <p>
+ * The {@link MetricsRegistry} singleton object can be retrieved using MetricsRegistryFactory::getMetricsRegistry. The {@link MetricsRegistryFactory} object
+ * is created during class initialization and cannot subsequently be changed.
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class MetricsRegistryFactory implements Closeable {
+
+    private static final Logger logger = LogManager.getLogger(MetricsRegistryFactory.class);
+
+    private final TelemetrySettings telemetrySettings;
+    private final MetricsRegistry metricsRegistry;
+
+    public MetricsRegistryFactory(TelemetrySettings telemetrySettings, Optional<Telemetry> telemetry) {
+        this.telemetrySettings = telemetrySettings;
+        this.metricsRegistry = metricsRegistry(telemetry);
+    }
+
+    /**
+     * Returns the {@link MetricsRegistry} instance
+     *
+     * @return MetricsRegistry instance
+     */
+    public MetricsRegistry getMetricsRegistry() {
+        return metricsRegistry;
+    }
+
+    /**
+     * Closes the {@link Tracer}
+     */
+    @Override
+    public void close() {
+        try {
+            metricsRegistry.close();
+        } catch (IOException e) {
+            logger.warn("Error closing MetricsRegistry", e);
+        }
+    }
+
+    private MetricsRegistry metricsRegistry(Optional<Telemetry> telemetry) {
+        MetricsRegistry metricsRegistry = telemetry.map(Telemetry::getMetricsTelemetry)
+            .map(metricsTelemetry -> createDefaultMetricsRegistry(metricsTelemetry))
+            .orElse(NoopMetricsRegistry.INSTANCE);
+        return metricsRegistry;
+    }
+
+    private MetricsRegistry createDefaultMetricsRegistry(MetricsTelemetry metricsTelemetry) {
+        return new DefaultMetricsRegistry(metricsTelemetry);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/metrics/NoopMetricsRegistryFactory.java b/server/src/main/java/org/opensearch/telemetry/metrics/NoopMetricsRegistryFactory.java
new file mode 100644
index 0000000000000..5137cb18e2cc0
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/metrics/NoopMetricsRegistryFactory.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.metrics.noop.NoopMetricsRegistry;
+
+import java.util.Optional;
+
+/**
+ * No-op implementation of {@link MetricsRegistryFactory}
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class NoopMetricsRegistryFactory extends MetricsRegistryFactory {
+    public NoopMetricsRegistryFactory() {
+        super(null, Optional.empty());
+    }
+
+    @Override
+    public MetricsRegistry getMetricsRegistry() {
+        return NoopMetricsRegistry.INSTANCE;
+    }
+
+    @Override
+    public void close() {
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/metrics/package-info.java b/server/src/main/java/org/opensearch/telemetry/metrics/package-info.java
new file mode 100644
index 0000000000000..ad4564e1d7773
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/metrics/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for telemetry.
+ */
+package org.opensearch.telemetry.metrics;
diff --git a/server/src/main/java/org/opensearch/telemetry/package-info.java b/server/src/main/java/org/opensearch/telemetry/package-info.java
new file mode 100644
index 0000000000000..4545f0ef5990e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for telemetry.
+ */
+package org.opensearch.telemetry;
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/AttributeNames.java b/server/src/main/java/org/opensearch/telemetry/tracing/AttributeNames.java
new file mode 100644
index 0000000000000..a9514c298ef88
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/AttributeNames.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.ExperimentalApi;
+
+/**
+ * Hold the Attribute names to avoid the duplication and consistency.
+ *
+ * @opensearch.experimental
+ */
+@ExperimentalApi
+public final class AttributeNames {
+
+    /**
+     * Constructor
+     */
+    private AttributeNames() {
+
+    }
+
+    /**
+     * HTTP Protocol Version
+     */
+    public static final String HTTP_PROTOCOL_VERSION = "http.version";
+
+    /**
+     * HTTP method
+     */
+    public static final String HTTP_METHOD = "http.method";
+
+    /**
+     * HTTP Request URI.
+     */
+    public static final String HTTP_URI = "http.uri";
+
+    /**
+     * Rest Request ID.
+     */
+    public static final String REST_REQ_ID = "rest.request_id";
+
+    /**
+     * Rest Request Raw Path.
+     */
+    public static final String REST_REQ_RAW_PATH = "rest.raw_path";
+
+    /**
+     * Trace key. To be used for on demand sampling.
+     */
+    public static final String TRACE = "trace";
+
+    /**
+     * Transport Service send request target host.
+     */
+    public static final String TRANSPORT_TARGET_HOST = "target_host";
+
+    /**
+     * Transport Service send request local host.
+     */
+    public static final String TRANSPORT_HOST = "host";
+
+    /**
+     * Action Name.
+     */
+    public static final String TRANSPORT_ACTION = "action";
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/NoopTracerFactory.java b/server/src/main/java/org/opensearch/telemetry/tracing/NoopTracerFactory.java
new file mode 100644
index 0000000000000..87762f342a653
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/NoopTracerFactory.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+
+import java.util.Optional;
+
+/**
+ * No-op implementation of TracerFactory
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class NoopTracerFactory extends TracerFactory {
+    public NoopTracerFactory() {
+        super(null, Optional.empty(), null);
+    }
+
+    @Override
+    public Tracer getTracer() {
+        return NoopTracer.INSTANCE;
+    }
+
+    @Override
+    public void close() {
+
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/SpanBuilder.java b/server/src/main/java/org/opensearch/telemetry/tracing/SpanBuilder.java
new file mode 100644
index 0000000000000..d97fbd371ab2a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/SpanBuilder.java
@@ -0,0 +1,153 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.core.common.Strings;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.transport.TcpChannel;
+import org.opensearch.transport.Transport;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Utility class, helps in creating the {@link SpanCreationContext} for span.
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public final class SpanBuilder {
+
+    private static final List<String> HEADERS_TO_BE_ADDED_AS_ATTRIBUTES = Arrays.asList(AttributeNames.TRACE);
+    /**
+     * Attribute name Separator
+     */
+    private static final String SEPARATOR = " ";
+
+    /**
+     * Constructor
+     */
+    private SpanBuilder() {
+
+    }
+
+    /**
+     * Creates {@link SpanCreationContext} from the {@link HttpRequest}
+     * @param request Http request.
+     * @return context.
+     */
+    public static SpanCreationContext from(HttpRequest request) {
+        return SpanCreationContext.server().name(createSpanName(request)).attributes(buildSpanAttributes(request));
+    }
+
+    /**
+     * Creates {@link SpanCreationContext} from the {@link RestRequest}
+     * @param request Rest request
+     * @return context
+     */
+    public static SpanCreationContext from(RestRequest request) {
+        return SpanCreationContext.client().name(createSpanName(request)).attributes(buildSpanAttributes(request));
+    }
+
+    /**
+     * Creates {@link SpanCreationContext} from Transport action and connection details.
+     * @param action action.
+     * @param connection transport connection.
+     * @return context
+     */
+    public static SpanCreationContext from(String action, Transport.Connection connection) {
+        return SpanCreationContext.server().name(createSpanName(action, connection)).attributes(buildSpanAttributes(action, connection));
+    }
+
+    private static String createSpanName(HttpRequest httpRequest) {
+        return httpRequest.method().name() + SEPARATOR + httpRequest.uri();
+    }
+
+    private static Attributes buildSpanAttributes(HttpRequest httpRequest) {
+        Attributes attributes = Attributes.create()
+            .addAttribute(AttributeNames.HTTP_URI, httpRequest.uri())
+            .addAttribute(AttributeNames.HTTP_METHOD, httpRequest.method().name())
+            .addAttribute(AttributeNames.HTTP_PROTOCOL_VERSION, httpRequest.protocolVersion().name());
+        populateHeader(httpRequest, attributes);
+        return attributes;
+    }
+
+    private static void populateHeader(HttpRequest httpRequest, Attributes attributes) {
+        HEADERS_TO_BE_ADDED_AS_ATTRIBUTES.forEach(x -> {
+            if (httpRequest.getHeaders() != null
+                && httpRequest.getHeaders().get(x) != null
+                && (httpRequest.getHeaders().get(x).isEmpty() == false)) {
+                attributes.addAttribute(x, Strings.collectionToCommaDelimitedString(httpRequest.getHeaders().get(x)));
+            }
+        });
+    }
+
+    private static String createSpanName(RestRequest restRequest) {
+        String spanName = "rest_request";
+        if (restRequest != null) {
+            try {
+                String methodName = restRequest.method().name();
+                // path() does the decoding, which may give error
+                String path = restRequest.path();
+                spanName = methodName + SEPARATOR + path;
+            } catch (Exception e) {
+                // swallow the exception and keep the default name.
+            }
+        }
+        return spanName;
+    }
+
+    private static Attributes buildSpanAttributes(RestRequest restRequest) {
+        if (restRequest != null) {
+            return Attributes.create()
+                .addAttribute(AttributeNames.REST_REQ_ID, restRequest.getRequestId())
+                .addAttribute(AttributeNames.REST_REQ_RAW_PATH, restRequest.rawPath());
+        } else {
+            return Attributes.EMPTY;
+        }
+    }
+
+    private static String createSpanName(String action, Transport.Connection connection) {
+        return action + SEPARATOR + (connection.getNode() != null ? connection.getNode().getHostAddress() : null);
+    }
+
+    private static Attributes buildSpanAttributes(String action, Transport.Connection connection) {
+        Attributes attributes = Attributes.create().addAttribute(AttributeNames.TRANSPORT_ACTION, action);
+        if (connection != null && connection.getNode() != null) {
+            attributes.addAttribute(AttributeNames.TRANSPORT_TARGET_HOST, connection.getNode().getHostAddress());
+        }
+        return attributes;
+    }
+
+    /**
+     * Creates {@link SpanCreationContext} from Inbound Handler.
+     * @param action action.
+     * @param tcpChannel tcp channel.
+     * @return context
+     */
+    public static SpanCreationContext from(String action, TcpChannel tcpChannel) {
+        return SpanCreationContext.server().name(createSpanName(action, tcpChannel)).attributes(buildSpanAttributes(action, tcpChannel));
+    }
+
+    private static String createSpanName(String action, TcpChannel tcpChannel) {
+        return action + SEPARATOR + (tcpChannel.getRemoteAddress() != null
+            ? tcpChannel.getRemoteAddress().getHostString()
+            : tcpChannel.getLocalAddress().getHostString());
+    }
+
+    private static Attributes buildSpanAttributes(String action, TcpChannel tcpChannel) {
+        Attributes attributes = Attributes.create().addAttribute(AttributeNames.TRANSPORT_ACTION, action);
+        attributes.addAttribute(AttributeNames.TRANSPORT_HOST, tcpChannel.getLocalAddress().getHostString());
+        return attributes;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/ThreadContextBasedTracerContextStorage.java b/server/src/main/java/org/opensearch/telemetry/tracing/ThreadContextBasedTracerContextStorage.java
new file mode 100644
index 0000000000000..208df90f65d74
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/ThreadContextBasedTracerContextStorage.java
@@ -0,0 +1,95 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.common.util.concurrent.ThreadContextStatePropagator;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Core's ThreadContext based TracerContextStorage implementation
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class ThreadContextBasedTracerContextStorage implements TracerContextStorage<String, Span>, ThreadContextStatePropagator {
+
+    private final ThreadContext threadContext;
+
+    private final TracingTelemetry tracingTelemetry;
+
+    public ThreadContextBasedTracerContextStorage(ThreadContext threadContext, TracingTelemetry tracingTelemetry) {
+        this.threadContext = Objects.requireNonNull(threadContext);
+        this.tracingTelemetry = Objects.requireNonNull(tracingTelemetry);
+        this.threadContext.registerThreadContextStatePropagator(this);
+    }
+
+    @Override
+    public Span get(String key) {
+        return getCurrentSpan(key);
+    }
+
+    @Override
+    public void put(String key, Span span) {
+        SpanReference currentSpanRef = threadContext.getTransient(key);
+        if (currentSpanRef == null) {
+            threadContext.putTransient(key, new SpanReference(span));
+        } else {
+            currentSpanRef.setSpan(span);
+        }
+    }
+
+    @Override
+    public Map<String, Object> transients(Map<String, Object> source) {
+        final Map<String, Object> transients = new HashMap<>();
+
+        if (source.containsKey(CURRENT_SPAN)) {
+            final SpanReference current = (SpanReference) source.get(CURRENT_SPAN);
+            if (current != null) {
+                transients.put(CURRENT_SPAN, new SpanReference(current.getSpan()));
+            }
+        }
+
+        return transients;
+    }
+
+    @Override
+    public Map<String, String> headers(Map<String, Object> source) {
+        final Map<String, String> headers = new HashMap<>();
+
+        if (source.containsKey(CURRENT_SPAN)) {
+            final SpanReference current = (SpanReference) source.get(CURRENT_SPAN);
+            if (current != null && current.getSpan() != null) {
+                tracingTelemetry.getContextPropagator().inject(current.getSpan(), (key, value) -> headers.put(key, value));
+            }
+        }
+
+        return headers;
+    }
+
+    Span getCurrentSpan(String key) {
+        Optional<Span> optionalSpanFromContext = spanFromThreadContext(key);
+        return optionalSpanFromContext.orElse(spanFromHeader());
+    }
+
+    private Optional<Span> spanFromThreadContext(String key) {
+        SpanReference currentSpanRef = threadContext.getTransient(key);
+        return (currentSpanRef == null) ? Optional.empty() : Optional.ofNullable(currentSpanRef.getSpan());
+    }
+
+    private Span spanFromHeader() {
+        Optional<Span> span = tracingTelemetry.getContextPropagator().extract(threadContext.getHeaders());
+        return span.orElse(null);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/TracerFactory.java b/server/src/main/java/org/opensearch/telemetry/tracing/TracerFactory.java
new file mode 100644
index 0000000000000..1cb73e0247c3a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/TracerFactory.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Optional;
+
+/**
+ * TracerManager represents a single global class that is used to access tracers.
+ * <p>
+ * The Tracer singleton object can be retrieved using tracerManager.getTracer(). The TracerManager object
+ * is created during class initialization and cannot subsequently be changed.
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+public class TracerFactory implements Closeable {
+
+    private static final Logger logger = LogManager.getLogger(TracerFactory.class);
+
+    private final TelemetrySettings telemetrySettings;
+    private final Tracer tracer;
+
+    public TracerFactory(TelemetrySettings telemetrySettings, Optional<Telemetry> telemetry, ThreadContext threadContext) {
+        this.telemetrySettings = telemetrySettings;
+        this.tracer = tracer(telemetry, threadContext);
+    }
+
+    /**
+     * Returns the tracer instance
+     *
+     * @return tracer instance
+     */
+    public Tracer getTracer() {
+        return tracer;
+    }
+
+    /**
+     * Closes the {@link Tracer}
+     */
+    @Override
+    public void close() {
+        try {
+            tracer.close();
+        } catch (IOException e) {
+            logger.warn("Error closing tracer", e);
+        }
+    }
+
+    private Tracer tracer(Optional<Telemetry> telemetry, ThreadContext threadContext) {
+        return telemetry.map(Telemetry::getTracingTelemetry)
+            .map(tracingTelemetry -> createDefaultTracer(tracingTelemetry, threadContext))
+            .map(defaultTracer -> createWrappedTracer(defaultTracer))
+            .orElse(NoopTracer.INSTANCE);
+    }
+
+    private Tracer createDefaultTracer(TracingTelemetry tracingTelemetry, ThreadContext threadContext) {
+        TracerContextStorage<String, Span> tracerContextStorage = new ThreadContextBasedTracerContextStorage(
+            threadContext,
+            tracingTelemetry
+        );
+        return new DefaultTracer(tracingTelemetry, tracerContextStorage);
+    }
+
+    private Tracer createWrappedTracer(Tracer defaultTracer) {
+        return new WrappedTracer(telemetrySettings, defaultTracer);
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/WrappedTracer.java b/server/src/main/java/org/opensearch/telemetry/tracing/WrappedTracer.java
new file mode 100644
index 0000000000000..b2308402379ac
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/WrappedTracer.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.annotation.InternalApi;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Wrapper implementation of Tracer. This delegates call to right tracer based on the tracer settings
+ *
+ * @opensearch.internal
+ */
+@InternalApi
+final class WrappedTracer implements Tracer {
+
+    private final Tracer defaultTracer;
+    private final TelemetrySettings telemetrySettings;
+
+    /**
+     * Creates WrappedTracer instance
+     *
+     * @param telemetrySettings telemetry settings
+     * @param defaultTracer default tracer instance
+     */
+    public WrappedTracer(TelemetrySettings telemetrySettings, Tracer defaultTracer) {
+        this.defaultTracer = defaultTracer;
+        this.telemetrySettings = telemetrySettings;
+    }
+
+    @Override
+    public Span startSpan(SpanCreationContext context) {
+        return getDelegateTracer().startSpan(context);
+    }
+
+    @Override
+    public SpanContext getCurrentSpan() {
+        Tracer delegateTracer = getDelegateTracer();
+        return delegateTracer.getCurrentSpan();
+    }
+
+    @Override
+    public ScopedSpan startScopedSpan(SpanCreationContext spanCreationContext) {
+        return getDelegateTracer().startScopedSpan(spanCreationContext);
+    }
+
+    @Override
+    public SpanScope withSpanInScope(Span span) {
+        return getDelegateTracer().withSpanInScope(span);
+    }
+
+    @Override
+    public void close() throws IOException {
+        defaultTracer.close();
+    }
+
+    // visible for testing
+    Tracer getDelegateTracer() {
+        return telemetrySettings.isTracingEnabled() ? defaultTracer : NoopTracer.INSTANCE;
+    }
+
+    @Override
+    public Span startSpan(SpanCreationContext spanCreationContext, Map<String, List<String>> headers) {
+        return defaultTracer.startSpan(spanCreationContext, headers);
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableHttpChannel.java b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableHttpChannel.java
new file mode 100644
index 0000000000000..03848e8e58207
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableHttpChannel.java
@@ -0,0 +1,95 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.channels;
+
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.http.HttpChannel;
+import org.opensearch.http.HttpResponse;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.listener.TraceableActionListener;
+
+import java.net.InetSocketAddress;
+import java.util.Objects;
+
+/**
+ * Tracer wrapped {@link HttpChannel}
+ */
+public class TraceableHttpChannel implements HttpChannel {
+    private final HttpChannel delegate;
+    private final Span span;
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     *
+     * @param delegate delegate
+     * @param span     span
+     * @param tracer tracer
+     */
+    private TraceableHttpChannel(HttpChannel delegate, Span span, Tracer tracer) {
+        this.span = Objects.requireNonNull(span);
+        this.delegate = Objects.requireNonNull(delegate);
+        this.tracer = Objects.requireNonNull(tracer);
+    }
+
+    /**
+     * Factory method.
+     *
+     * @param delegate delegate
+     * @param span     span
+     * @param tracer tracer
+     * @return http channel
+     */
+    public static HttpChannel create(HttpChannel delegate, Span span, Tracer tracer) {
+        if (FeatureFlags.isEnabled(FeatureFlags.TELEMETRY) == true) {
+            return new TraceableHttpChannel(delegate, span, tracer);
+        } else {
+            return delegate;
+        }
+    }
+
+    @Override
+    public void handleException(Exception ex) {
+        span.addEvent("The HttpChannel was closed without sending the response");
+        span.setError(ex);
+        span.endSpan();
+    }
+
+    @Override
+    public void close() {
+        delegate.close();
+    }
+
+    @Override
+    public void addCloseListener(ActionListener<Void> listener) {
+        delegate.addCloseListener(listener);
+    }
+
+    @Override
+    public boolean isOpen() {
+        return delegate.isOpen();
+    }
+
+    @Override
+    public void sendResponse(HttpResponse response, ActionListener<Void> listener) {
+        delegate.sendResponse(response, TraceableActionListener.create(listener, span, tracer));
+    }
+
+    @Override
+    public InetSocketAddress getLocalAddress() {
+        return delegate.getLocalAddress();
+    }
+
+    @Override
+    public InetSocketAddress getRemoteAddress() {
+        return delegate.getRemoteAddress();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableRestChannel.java b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableRestChannel.java
new file mode 100644
index 0000000000000..d256c9d4d0e53
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableRestChannel.java
@@ -0,0 +1,106 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.channels;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.rest.RestChannel;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestResponse;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Tracer wrapped {@link RestChannel}
+ */
+public class TraceableRestChannel implements RestChannel {
+
+    private final RestChannel delegate;
+    private final Span span;
+
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     *
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     */
+    private TraceableRestChannel(RestChannel delegate, Span span, Tracer tracer) {
+        this.span = Objects.requireNonNull(span);
+        this.delegate = Objects.requireNonNull(delegate);
+        this.tracer = Objects.requireNonNull(tracer);
+    }
+
+    /**
+     * Factory method.
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     * @return rest channel
+     */
+    public static RestChannel create(RestChannel delegate, Span span, Tracer tracer) {
+        if (FeatureFlags.isEnabled(FeatureFlags.TELEMETRY) == true) {
+            return new TraceableRestChannel(delegate, span, tracer);
+        } else {
+            return delegate;
+        }
+    }
+
+    @Override
+    public XContentBuilder newBuilder() throws IOException {
+        return delegate.newBuilder();
+    }
+
+    @Override
+    public XContentBuilder newErrorBuilder() throws IOException {
+        return delegate.newErrorBuilder();
+    }
+
+    @Override
+    public XContentBuilder newBuilder(MediaType mediaType, boolean useFiltering) throws IOException {
+        return delegate.newBuilder(mediaType, useFiltering);
+    }
+
+    @Override
+    public XContentBuilder newBuilder(MediaType mediaType, MediaType responseContentType, boolean useFiltering) throws IOException {
+        return delegate.newBuilder(mediaType, responseContentType, useFiltering);
+    }
+
+    @Override
+    public BytesStreamOutput bytesOutput() {
+        return delegate.bytesOutput();
+    }
+
+    @Override
+    public RestRequest request() {
+        return delegate.request();
+    }
+
+    @Override
+    public boolean detailedErrorsEnabled() {
+        return delegate.detailedErrorsEnabled();
+    }
+
+    @Override
+    public void sendResponse(RestResponse response) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.sendResponse(response);
+        } finally {
+            span.endSpan();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableTcpTransportChannel.java b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableTcpTransportChannel.java
new file mode 100644
index 0000000000000..333e06eb037cb
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/channels/TraceableTcpTransportChannel.java
@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.channels;
+
+import org.opensearch.Version;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.transport.BaseTcpTransportChannel;
+import org.opensearch.transport.TcpTransportChannel;
+import org.opensearch.transport.TransportChannel;
+
+import java.io.IOException;
+
+/**
+ * Tracer wrapped {@link TransportChannel}
+ */
+public class TraceableTcpTransportChannel extends BaseTcpTransportChannel {
+
+    private final TransportChannel delegate;
+    private final Span span;
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     */
+    public TraceableTcpTransportChannel(TcpTransportChannel delegate, Span span, Tracer tracer) {
+        super(delegate.getChannel());
+        this.delegate = delegate;
+        this.span = span;
+        this.tracer = tracer;
+    }
+
+    /**
+     * Factory method.
+     *
+     * @param delegate delegate
+     * @param span     span
+     * @param tracer tracer
+     * @return transport channel
+     */
+    public static TransportChannel create(TcpTransportChannel delegate, final Span span, final Tracer tracer) {
+        if (FeatureFlags.isEnabled(FeatureFlags.TELEMETRY) == true) {
+            delegate.getChannel().addCloseListener(new ActionListener<Void>() {
+                @Override
+                public void onResponse(Void unused) {
+                    onFailure(null);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    span.addEvent("The TransportChannel was closed without sending the response");
+                    span.setError(e);
+                    span.endSpan();
+                }
+            });
+
+            return new TraceableTcpTransportChannel(delegate, span, tracer);
+        } else {
+            return delegate;
+        }
+    }
+
+    @Override
+    public String getProfileName() {
+        return delegate.getProfileName();
+    }
+
+    @Override
+    public String getChannelType() {
+        return delegate.getChannelType();
+    }
+
+    @Override
+    public void sendResponse(TransportResponse response) throws IOException {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.sendResponse(response);
+        } catch (final IOException ex) {
+            span.setError(ex);
+            throw ex;
+        } finally {
+            span.endSpan();
+        }
+    }
+
+    @Override
+    public void sendResponse(Exception exception) throws IOException {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.sendResponse(exception);
+        } finally {
+            span.setError(exception);
+            span.endSpan();
+        }
+    }
+
+    @Override
+    public Version getVersion() {
+        return delegate.getVersion();
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/channels/package-info.java b/server/src/main/java/org/opensearch/telemetry/tracing/channels/package-info.java
new file mode 100644
index 0000000000000..ee4b675d5dc30
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/channels/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.tracing.channels;
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/handler/TraceableTransportResponseHandler.java b/server/src/main/java/org/opensearch/telemetry/tracing/handler/TraceableTransportResponseHandler.java
new file mode 100644
index 0000000000000..538bf82a1dbec
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/handler/TraceableTransportResponseHandler.java
@@ -0,0 +1,108 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.handler;
+
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Tracer wrapped {@link TransportResponseHandler}
+ * @param <T> TransportResponse
+ */
+public class TraceableTransportResponseHandler<T extends TransportResponse> implements TransportResponseHandler<T> {
+
+    private final Span span;
+    private final TransportResponseHandler<T> delegate;
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     *
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     */
+    private TraceableTransportResponseHandler(TransportResponseHandler<T> delegate, Span span, Tracer tracer) {
+        this.delegate = Objects.requireNonNull(delegate);
+        this.span = Objects.requireNonNull(span);
+        this.tracer = Objects.requireNonNull(tracer);
+    }
+
+    /**
+     * Factory method.
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     * @return transportResponseHandler
+     */
+    public static <S extends TransportResponse> TransportResponseHandler<S> create(
+        TransportResponseHandler<S> delegate,
+        Span span,
+        Tracer tracer
+    ) {
+        if (FeatureFlags.isEnabled(FeatureFlags.TELEMETRY) == true) {
+            return new TraceableTransportResponseHandler<S>(delegate, span, tracer);
+        } else {
+            return delegate;
+        }
+    }
+
+    @Override
+    public T read(StreamInput in) throws IOException {
+        return delegate.read(in);
+    }
+
+    @Override
+    public void handleResponse(T response) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.handleResponse(response);
+        } finally {
+            span.endSpan();
+        }
+    }
+
+    @Override
+    public void handleException(TransportException exp) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.handleException(exp);
+        } finally {
+            span.setError(exp);
+            span.endSpan();
+        }
+    }
+
+    @Override
+    public String executor() {
+        return delegate.executor();
+    }
+
+    @Override
+    public String toString() {
+        return delegate.toString();
+    }
+
+    @Override
+    public void handleRejection(Exception exp) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.handleRejection(exp);
+        } finally {
+            span.setError(exp);
+            span.endSpan();
+        }
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/handler/package-info.java b/server/src/main/java/org/opensearch/telemetry/tracing/handler/package-info.java
new file mode 100644
index 0000000000000..ff9f8f57dc07c
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/handler/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.tracing.handler;
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/listener/TraceableActionListener.java b/server/src/main/java/org/opensearch/telemetry/tracing/listener/TraceableActionListener.java
new file mode 100644
index 0000000000000..3e201641a529b
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/listener/TraceableActionListener.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.listener;
+
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+
+import java.util.Objects;
+
+/**
+ * Tracer wrapped {@link ActionListener}
+ * @param <Response> response.
+ */
+public class TraceableActionListener<Response> implements ActionListener<Response> {
+
+    private final ActionListener<Response> delegate;
+    private final Span span;
+    private final Tracer tracer;
+
+    /**
+     * Constructor.
+     *
+     * @param delegate delegate
+     * @param span     span
+     * @param tracer tracer
+     */
+    private TraceableActionListener(ActionListener<Response> delegate, Span span, Tracer tracer) {
+        this.delegate = Objects.requireNonNull(delegate);
+        this.span = Objects.requireNonNull(span);
+        this.tracer = Objects.requireNonNull(tracer);
+    }
+
+    /**
+     * Factory method.
+     * @param delegate delegate
+     * @param span span
+     * @param tracer tracer
+     * @return action listener
+     */
+    public static <Response> ActionListener<Response> create(ActionListener<Response> delegate, Span span, Tracer tracer) {
+        if (FeatureFlags.isEnabled(FeatureFlags.TELEMETRY) == true) {
+            return new TraceableActionListener<Response>(delegate, span, tracer);
+        } else {
+            return delegate;
+        }
+    }
+
+    @Override
+    public void onResponse(Response response) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.onResponse(response);
+        } finally {
+            span.endSpan();
+        }
+
+    }
+
+    @Override
+    public void onFailure(Exception e) {
+        try (SpanScope scope = tracer.withSpanInScope(span)) {
+            delegate.onFailure(e);
+        } finally {
+            span.setError(e);
+            span.endSpan();
+        }
+
+    }
+}
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/listener/package-info.java b/server/src/main/java/org/opensearch/telemetry/tracing/listener/package-info.java
new file mode 100644
index 0000000000000..5dcb570c2bb2e
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/listener/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.tracing.listener;
diff --git a/server/src/main/java/org/opensearch/telemetry/tracing/package-info.java b/server/src/main/java/org/opensearch/telemetry/tracing/package-info.java
new file mode 100644
index 0000000000000..4ac1e4c212c81
--- /dev/null
+++ b/server/src/main/java/org/opensearch/telemetry/tracing/package-info.java
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * This package contains classes needed for tracing requests.
+ */
+package org.opensearch.telemetry.tracing;
diff --git a/server/src/main/java/org/opensearch/threadpool/AutoQueueAdjustingExecutorBuilder.java b/server/src/main/java/org/opensearch/threadpool/AutoQueueAdjustingExecutorBuilder.java
index 2bac5eba9fc28..883abec3f01a1 100644
--- a/server/src/main/java/org/opensearch/threadpool/AutoQueueAdjustingExecutorBuilder.java
+++ b/server/src/main/java/org/opensearch/threadpool/AutoQueueAdjustingExecutorBuilder.java
@@ -48,10 +48,13 @@
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * A builder for executors that automatically adjust the queue length as needed, depending on
  * Little's Law. See https://en.wikipedia.org/wiki/Little's_law for more information.
+ *
+ * @opensearch.internal
  */
 public final class AutoQueueAdjustingExecutorBuilder extends ExecutorBuilder<AutoQueueAdjustingExecutorBuilder.AutoExecutorSettings> {
 
@@ -61,6 +64,7 @@ public final class AutoQueueAdjustingExecutorBuilder extends ExecutorBuilder<Aut
     private final Setting<Integer> maxQueueSizeSetting;
     private final Setting<TimeValue> targetedResponseTimeSetting;
     private final Setting<Integer> frameSizeSetting;
+    private final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener;
 
     AutoQueueAdjustingExecutorBuilder(
         final Settings settings,
@@ -70,6 +74,19 @@ public final class AutoQueueAdjustingExecutorBuilder extends ExecutorBuilder<Aut
         final int minQueueSize,
         final int maxQueueSize,
         final int frameSize
+    ) {
+        this(settings, name, size, initialQueueSize, minQueueSize, maxQueueSize, frameSize, null);
+    }
+
+    AutoQueueAdjustingExecutorBuilder(
+        final Settings settings,
+        final String name,
+        final int size,
+        final int initialQueueSize,
+        final int minQueueSize,
+        final int maxQueueSize,
+        final int frameSize,
+        final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener
     ) {
         super(name);
         final String prefix = "thread_pool." + name;
@@ -184,6 +201,7 @@ public Iterator<Setting<?>> settings() {
             Setting.Property.Deprecated,
             Setting.Property.Deprecated
         );
+        this.runnableTaskListener = runnableTaskListener;
     }
 
     @Override
@@ -230,7 +248,8 @@ ThreadPool.ExecutorHolder build(final AutoExecutorSettings settings, final Threa
             frameSize,
             targetedResponseTime,
             threadFactory,
-            threadContext
+            threadContext,
+            runnableTaskListener
         );
         // TODO: in a subsequent change we hope to extend ThreadPool.Info to be more specific for the thread pool type
         final ThreadPool.Info info = new ThreadPool.Info(
diff --git a/server/src/main/java/org/opensearch/threadpool/CancellableAdapter.java b/server/src/main/java/org/opensearch/threadpool/CancellableAdapter.java
index e4133e89485bc..cb37762892599 100644
--- a/server/src/main/java/org/opensearch/threadpool/CancellableAdapter.java
+++ b/server/src/main/java/org/opensearch/threadpool/CancellableAdapter.java
@@ -36,6 +36,11 @@
 
 import java.util.concurrent.Future;
 
+/**
+ * A cancellable adapter
+ *
+ * @opensearch.internal
+ */
 class CancellableAdapter implements Scheduler.Cancellable {
     private Future<?> future;
 
diff --git a/server/src/main/java/org/opensearch/threadpool/ExecutorBuilder.java b/server/src/main/java/org/opensearch/threadpool/ExecutorBuilder.java
index b9f4e31d5766f..d26131484ba71 100644
--- a/server/src/main/java/org/opensearch/threadpool/ExecutorBuilder.java
+++ b/server/src/main/java/org/opensearch/threadpool/ExecutorBuilder.java
@@ -43,6 +43,8 @@
  * Base class for executor builders.
  *
  * @param <U> the underlying type of the executor settings
+ *
+ * @opensearch.internal
  */
 public abstract class ExecutorBuilder<U extends ExecutorBuilder.ExecutorSettings> {
 
diff --git a/server/src/main/java/org/opensearch/threadpool/FixedExecutorBuilder.java b/server/src/main/java/org/opensearch/threadpool/FixedExecutorBuilder.java
index 7eeea8e1b3f4c..bb21c234e58fe 100644
--- a/server/src/main/java/org/opensearch/threadpool/FixedExecutorBuilder.java
+++ b/server/src/main/java/org/opensearch/threadpool/FixedExecutorBuilder.java
@@ -47,6 +47,8 @@
 
 /**
  * A builder for fixed executors.
+ *
+ * @opensearch.internal
  */
 public final class FixedExecutorBuilder extends ExecutorBuilder<FixedExecutorBuilder.FixedExecutorSettings> {
 
diff --git a/server/src/main/java/org/opensearch/threadpool/RunnableTaskExecutionListener.java b/server/src/main/java/org/opensearch/threadpool/RunnableTaskExecutionListener.java
new file mode 100644
index 0000000000000..03cd66f80d044
--- /dev/null
+++ b/server/src/main/java/org/opensearch/threadpool/RunnableTaskExecutionListener.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.threadpool;
+
+/**
+ * Listener for events when a runnable execution starts or finishes on a thread and is aware of the task for which the
+ * runnable is associated to.
+ */
+public interface RunnableTaskExecutionListener {
+
+    /**
+     * Sends an update when ever a task's execution start on a thread
+     *
+     * @param taskId of task which has started
+     * @param threadId of thread which is executing the task
+     */
+    void taskExecutionStartedOnThread(long taskId, long threadId);
+
+    /**
+     *
+     * Sends an update when task execution finishes on a thread
+     *
+     * @param taskId of task which has finished
+     * @param threadId of thread which executed the task
+     */
+    void taskExecutionFinishedOnThread(long taskId, long threadId);
+}
diff --git a/server/src/main/java/org/opensearch/threadpool/ScalingExecutorBuilder.java b/server/src/main/java/org/opensearch/threadpool/ScalingExecutorBuilder.java
index 6a183b01ef1e9..2690a3cc30238 100644
--- a/server/src/main/java/org/opensearch/threadpool/ScalingExecutorBuilder.java
+++ b/server/src/main/java/org/opensearch/threadpool/ScalingExecutorBuilder.java
@@ -48,6 +48,8 @@
 
 /**
  * A builder for scaling executors.
+ *
+ * @opensearch.internal
  */
 public final class ScalingExecutorBuilder extends ExecutorBuilder<ScalingExecutorBuilder.ScalingExecutorSettings> {
 
diff --git a/server/src/main/java/org/opensearch/threadpool/ScheduledCancellableAdapter.java b/server/src/main/java/org/opensearch/threadpool/ScheduledCancellableAdapter.java
index 31672363d2eaf..7e756e827b69e 100644
--- a/server/src/main/java/org/opensearch/threadpool/ScheduledCancellableAdapter.java
+++ b/server/src/main/java/org/opensearch/threadpool/ScheduledCancellableAdapter.java
@@ -38,6 +38,11 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * A cancellable adapter that is scheduled
+ *
+ * @opensearch.internal
+ */
 class ScheduledCancellableAdapter implements Scheduler.ScheduledCancellable {
     private final ScheduledFuture<?> scheduledFuture;
 
diff --git a/server/src/main/java/org/opensearch/threadpool/Scheduler.java b/server/src/main/java/org/opensearch/threadpool/Scheduler.java
index 3f0dff48fb0f5..86c322ec89dd7 100644
--- a/server/src/main/java/org/opensearch/threadpool/Scheduler.java
+++ b/server/src/main/java/org/opensearch/threadpool/Scheduler.java
@@ -39,7 +39,7 @@
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.OpenSearchAbortPolicy;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 
 import java.util.concurrent.Delayed;
 import java.util.concurrent.Future;
@@ -53,6 +53,8 @@
 
 /**
  * Scheduler that allows to schedule one-shot and periodic commands.
+ *
+ * @opensearch.internal
  */
 public interface Scheduler {
 
diff --git a/server/src/main/java/org/opensearch/threadpool/TaskAwareRunnable.java b/server/src/main/java/org/opensearch/threadpool/TaskAwareRunnable.java
new file mode 100644
index 0000000000000..183b9b2f4cf9a
--- /dev/null
+++ b/server/src/main/java/org/opensearch/threadpool/TaskAwareRunnable.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.threadpool;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.common.util.concurrent.WrappedRunnable;
+import org.opensearch.tasks.TaskManager;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static java.lang.Thread.currentThread;
+import static org.opensearch.tasks.TaskResourceTrackingService.TASK_ID;
+
+/**
+ * Responsible for wrapping the original task's runnable and sending updates on when it starts and finishes to
+ * entities listening to the events.
+ *
+ * It's able to associate runnable with a task with the help of task Id available in thread context.
+ */
+public class TaskAwareRunnable extends AbstractRunnable implements WrappedRunnable {
+
+    private static final Logger logger = LogManager.getLogger(TaskManager.class);
+
+    private final Runnable original;
+    private final ThreadContext threadContext;
+    private final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener;
+
+    public TaskAwareRunnable(
+        final ThreadContext threadContext,
+        final Runnable original,
+        final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener
+    ) {
+        this.original = original;
+        this.threadContext = threadContext;
+        this.runnableTaskListener = runnableTaskListener;
+    }
+
+    @Override
+    public void onFailure(Exception e) {
+        ExceptionsHelper.reThrowIfNotNull(e);
+    }
+
+    @Override
+    public boolean isForceExecution() {
+        return original instanceof AbstractRunnable && ((AbstractRunnable) original).isForceExecution();
+    }
+
+    @Override
+    public void onRejection(final Exception e) {
+        if (original instanceof AbstractRunnable) {
+            ((AbstractRunnable) original).onRejection(e);
+        } else {
+            ExceptionsHelper.reThrowIfNotNull(e);
+        }
+    }
+
+    @Override
+    protected void doRun() throws Exception {
+        assert runnableTaskListener.get() != null : "Listener should be attached";
+        Long taskId = threadContext.getTransient(TASK_ID);
+        if (Objects.nonNull(taskId)) {
+            runnableTaskListener.get().taskExecutionStartedOnThread(taskId, currentThread().getId());
+        } else {
+            logger.debug("Task Id not available in thread context. Skipping update. Thread Info: {}", Thread.currentThread());
+        }
+        try {
+            original.run();
+        } finally {
+            if (Objects.nonNull(taskId)) {
+                runnableTaskListener.get().taskExecutionFinishedOnThread(taskId, currentThread().getId());
+            }
+        }
+    }
+
+    @Override
+    public Runnable unwrap() {
+        return original;
+    }
+}
diff --git a/server/src/main/java/org/opensearch/threadpool/ThreadPool.java b/server/src/main/java/org/opensearch/threadpool/ThreadPool.java
index c2530ccee5588..a09c9efbd77cf 100644
--- a/server/src/main/java/org/opensearch/threadpool/ThreadPool.java
+++ b/server/src/main/java/org/opensearch/threadpool/ThreadPool.java
@@ -36,22 +36,24 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.SizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.concurrent.XRejectedExecutionHandler;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.node.Node;
-import org.opensearch.node.ReportingService;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -68,14 +70,26 @@
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.unmodifiableMap;
 
+/**
+ * The OpenSearch threadpool class
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
 public class ThreadPool implements ReportingService<ThreadPoolInfo>, Scheduler {
 
     private static final Logger logger = LogManager.getLogger(ThreadPool.class);
 
+    /**
+     * The threadpool names.
+     *
+     * @opensearch.internal
+     */
     public static class Names {
         public static final String SAME = "same";
         public static final String GENERIC = "generic";
@@ -96,8 +110,19 @@ public static class Names {
         public static final String FETCH_SHARD_STORE = "fetch_shard_store";
         public static final String SYSTEM_READ = "system_read";
         public static final String SYSTEM_WRITE = "system_write";
+        public static final String TRANSLOG_TRANSFER = "translog_transfer";
+        public static final String TRANSLOG_SYNC = "translog_sync";
+        public static final String REMOTE_PURGE = "remote_purge";
+        public static final String REMOTE_REFRESH_RETRY = "remote_refresh_retry";
+        public static final String REMOTE_RECOVERY = "remote_recovery";
+        public static final String INDEX_SEARCHER = "index_searcher";
     }
 
+    /**
+     * The threadpool type.
+     *
+     * @opensearch.internal
+     */
     public enum ThreadPoolType {
         DIRECT("direct"),
         FIXED("fixed"),
@@ -155,6 +180,14 @@ public static ThreadPoolType fromType(String type) {
         map.put(Names.SEARCH_THROTTLED, ThreadPoolType.FIXED_AUTO_QUEUE_SIZE);
         map.put(Names.SYSTEM_READ, ThreadPoolType.FIXED);
         map.put(Names.SYSTEM_WRITE, ThreadPoolType.FIXED);
+        map.put(Names.TRANSLOG_TRANSFER, ThreadPoolType.SCALING);
+        map.put(Names.TRANSLOG_SYNC, ThreadPoolType.FIXED);
+        map.put(Names.REMOTE_PURGE, ThreadPoolType.SCALING);
+        map.put(Names.REMOTE_REFRESH_RETRY, ThreadPoolType.SCALING);
+        map.put(Names.REMOTE_RECOVERY, ThreadPoolType.SCALING);
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            map.put(Names.INDEX_SEARCHER, ThreadPoolType.FIXED_AUTO_QUEUE_SIZE);
+        }
         THREAD_POOL_TYPES = Collections.unmodifiableMap(map);
     }
 
@@ -184,6 +217,14 @@ public Collection<ExecutorBuilder> builders() {
     );
 
     public ThreadPool(final Settings settings, final ExecutorBuilder<?>... customBuilders) {
+        this(settings, null, customBuilders);
+    }
+
+    public ThreadPool(
+        final Settings settings,
+        final AtomicReference<RunnableTaskExecutionListener> runnableTaskListener,
+        final ExecutorBuilder<?>... customBuilders
+    ) {
         assert Node.NODE_NAME_SETTING.exists(settings);
 
         final Map<String, ExecutorBuilder> builders = new HashMap<>();
@@ -197,11 +238,20 @@ public ThreadPool(final Settings settings, final ExecutorBuilder<?>... customBui
         builders.put(Names.ANALYZE, new FixedExecutorBuilder(settings, Names.ANALYZE, 1, 16));
         builders.put(
             Names.SEARCH,
-            new AutoQueueAdjustingExecutorBuilder(settings, Names.SEARCH, searchThreadPoolSize(allocatedProcessors), 1000, 1000, 1000, 2000)
+            new AutoQueueAdjustingExecutorBuilder(
+                settings,
+                Names.SEARCH,
+                searchThreadPoolSize(allocatedProcessors),
+                1000,
+                1000,
+                1000,
+                2000,
+                runnableTaskListener
+            )
         );
         builders.put(
             Names.SEARCH_THROTTLED,
-            new AutoQueueAdjustingExecutorBuilder(settings, Names.SEARCH_THROTTLED, 1, 100, 100, 100, 200)
+            new AutoQueueAdjustingExecutorBuilder(settings, Names.SEARCH_THROTTLED, 1, 100, 100, 100, 200, runnableTaskListener)
         );
         builders.put(Names.MANAGEMENT, new ScalingExecutorBuilder(Names.MANAGEMENT, 1, 5, TimeValue.timeValueMinutes(5)));
         // no queue as this means clients will need to handle rejections on listener queue even if the operation succeeded
@@ -222,6 +272,35 @@ public ThreadPool(final Settings settings, final ExecutorBuilder<?>... customBui
         );
         builders.put(Names.SYSTEM_READ, new FixedExecutorBuilder(settings, Names.SYSTEM_READ, halfProcMaxAt5, 2000, false));
         builders.put(Names.SYSTEM_WRITE, new FixedExecutorBuilder(settings, Names.SYSTEM_WRITE, halfProcMaxAt5, 1000, false));
+        builders.put(
+            Names.TRANSLOG_TRANSFER,
+            new ScalingExecutorBuilder(Names.TRANSLOG_TRANSFER, 1, halfProcMaxAt10, TimeValue.timeValueMinutes(5))
+        );
+        builders.put(Names.TRANSLOG_SYNC, new FixedExecutorBuilder(settings, Names.TRANSLOG_SYNC, allocatedProcessors * 4, 10000));
+        builders.put(Names.REMOTE_PURGE, new ScalingExecutorBuilder(Names.REMOTE_PURGE, 1, halfProcMaxAt5, TimeValue.timeValueMinutes(5)));
+        builders.put(
+            Names.REMOTE_REFRESH_RETRY,
+            new ScalingExecutorBuilder(Names.REMOTE_REFRESH_RETRY, 1, halfProcMaxAt10, TimeValue.timeValueMinutes(5))
+        );
+        builders.put(
+            Names.REMOTE_RECOVERY,
+            new ScalingExecutorBuilder(Names.REMOTE_RECOVERY, 1, halfProcMaxAt10, TimeValue.timeValueMinutes(5))
+        );
+        if (FeatureFlags.isEnabled(FeatureFlags.CONCURRENT_SEGMENT_SEARCH)) {
+            builders.put(
+                Names.INDEX_SEARCHER,
+                new AutoQueueAdjustingExecutorBuilder(
+                    settings,
+                    Names.INDEX_SEARCHER,
+                    allocatedProcessors,
+                    1000,
+                    1000,
+                    1000,
+                    2000,
+                    runnableTaskListener
+                )
+            );
+        }
 
         for (final ExecutorBuilder<?> builder : customBuilders) {
             if (builders.containsKey(builder.name())) {
@@ -279,6 +358,19 @@ public long relativeTimeInNanos() {
         return cachedTimeThread.relativeTimeInNanos();
     }
 
+    /**
+     * Returns a value of nanoseconds that may be used for relative time calculations
+     * that require the highest precision possible. Performance critical code must use
+     * either {@link #relativeTimeInNanos()} or {@link #relativeTimeInMillis()} which
+     * give better performance at the cost of lower precision.
+     *
+     * This method should only be used for calculating time deltas. For an epoch based
+     * timestamp, see {@link #absoluteTimeInMillis()}.
+     */
+    public long preciseRelativeTimeInNanos() {
+        return System.nanoTime();
+    }
+
     /**
      * Returns the value of milliseconds since UNIX epoch.
      *
@@ -317,19 +409,21 @@ public ThreadPoolStats stats() {
             long rejected = -1;
             int largest = -1;
             long completed = -1;
-            if (holder.executor() instanceof ThreadPoolExecutor) {
-                ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) holder.executor();
+            long waitTimeNanos = -1;
+            if (holder.executor() instanceof OpenSearchThreadPoolExecutor) {
+                OpenSearchThreadPoolExecutor threadPoolExecutor = (OpenSearchThreadPoolExecutor) holder.executor();
                 threads = threadPoolExecutor.getPoolSize();
                 queue = threadPoolExecutor.getQueue().size();
                 active = threadPoolExecutor.getActiveCount();
                 largest = threadPoolExecutor.getLargestPoolSize();
                 completed = threadPoolExecutor.getCompletedTaskCount();
+                waitTimeNanos = threadPoolExecutor.getPoolWaitTimeNanos();
                 RejectedExecutionHandler rejectedExecutionHandler = threadPoolExecutor.getRejectedExecutionHandler();
                 if (rejectedExecutionHandler instanceof XRejectedExecutionHandler) {
                     rejected = ((XRejectedExecutionHandler) rejectedExecutionHandler).rejected();
                 }
             }
-            stats.add(new ThreadPoolStats.Stats(name, threads, queue, active, rejected, largest, completed));
+            stats.add(new ThreadPoolStats.Stats(name, threads, queue, active, rejected, largest, completed, waitTimeNanos));
         }
         return new ThreadPoolStats(stats);
     }
@@ -376,7 +470,7 @@ public ExecutorService executor(String name) {
      * @return a ScheduledFuture who's get will return when the task is has been added to its target thread pool and throw an exception if
      *         the task is canceled before it was added to its target thread pool. Once the task has been added to its target thread pool
      *         the ScheduledFuture will cannot interact with it.
-     * @throws org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException if the task cannot be scheduled for execution
+     * @throws OpenSearchRejectedExecutionException if the task cannot be scheduled for execution
      */
     @Override
     public ScheduledCancellable schedule(Runnable command, TimeValue delay, String executor) {
@@ -652,6 +746,11 @@ ExecutorService executor() {
         }
     }
 
+    /**
+     * The thread pool information.
+     *
+     * @opensearch.internal
+     */
     public static class Info implements Writeable, ToXContentFragment {
 
         private final String name;
diff --git a/server/src/main/java/org/opensearch/threadpool/ThreadPoolInfo.java b/server/src/main/java/org/opensearch/threadpool/ThreadPoolInfo.java
index 3b34734841c0d..f49ad34e70119 100644
--- a/server/src/main/java/org/opensearch/threadpool/ThreadPoolInfo.java
+++ b/server/src/main/java/org/opensearch/threadpool/ThreadPoolInfo.java
@@ -32,16 +32,21 @@
 
 package org.opensearch.threadpool;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Information about a threadpool
+ *
+ * @opensearch.internal
+ */
 public class ThreadPoolInfo implements ReportingService.Info, Iterable<ThreadPool.Info> {
 
     private final List<ThreadPool.Info> infos;
diff --git a/server/src/main/java/org/opensearch/threadpool/ThreadPoolStats.java b/server/src/main/java/org/opensearch/threadpool/ThreadPoolStats.java
index 92273e15fa280..7b4c1504d927a 100644
--- a/server/src/main/java/org/opensearch/threadpool/ThreadPoolStats.java
+++ b/server/src/main/java/org/opensearch/threadpool/ThreadPoolStats.java
@@ -32,20 +32,32 @@
 
 package org.opensearch.threadpool;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.Version;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Stats for a threadpool
+ *
+ * @opensearch.internal
+ */
 public class ThreadPoolStats implements Writeable, ToXContentFragment, Iterable<ThreadPoolStats.Stats> {
 
+    /**
+     * The statistics.
+     *
+     * @opensearch.internal
+     */
     public static class Stats implements Writeable, ToXContentFragment, Comparable<Stats> {
 
         private final String name;
@@ -55,8 +67,9 @@ public static class Stats implements Writeable, ToXContentFragment, Comparable<S
         private final long rejected;
         private final int largest;
         private final long completed;
+        private final long waitTimeNanos;
 
-        public Stats(String name, int threads, int queue, int active, long rejected, int largest, long completed) {
+        public Stats(String name, int threads, int queue, int active, long rejected, int largest, long completed, long waitTimeNanos) {
             this.name = name;
             this.threads = threads;
             this.queue = queue;
@@ -64,6 +77,7 @@ public Stats(String name, int threads, int queue, int active, long rejected, int
             this.rejected = rejected;
             this.largest = largest;
             this.completed = completed;
+            this.waitTimeNanos = waitTimeNanos;
         }
 
         public Stats(StreamInput in) throws IOException {
@@ -74,6 +88,7 @@ public Stats(StreamInput in) throws IOException {
             rejected = in.readLong();
             largest = in.readInt();
             completed = in.readLong();
+            waitTimeNanos = in.getVersion().onOrAfter(Version.V_2_11_0) ? in.readLong() : -1;
         }
 
         @Override
@@ -85,6 +100,9 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(rejected);
             out.writeInt(largest);
             out.writeLong(completed);
+            if (out.getVersion().onOrAfter(Version.V_2_11_0)) {
+                out.writeLong(waitTimeNanos);
+            }
         }
 
         public String getName() {
@@ -115,6 +133,14 @@ public long getCompleted() {
             return this.completed;
         }
 
+        public TimeValue getWaitTime() {
+            return TimeValue.timeValueNanos(waitTimeNanos);
+        }
+
+        public long getWaitTimeNanos() {
+            return waitTimeNanos;
+        }
+
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.startObject(name);
@@ -136,6 +162,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             if (completed != -1) {
                 builder.field(Fields.COMPLETED, completed);
             }
+            if (waitTimeNanos != -1) {
+                if (builder.humanReadable()) {
+                    builder.field(Fields.WAIT_TIME, getWaitTime());
+                }
+                builder.field(Fields.WAIT_TIME_NANOS, getWaitTimeNanos());
+            }
             builder.endObject();
             return builder;
         }
@@ -187,6 +219,8 @@ static final class Fields {
         static final String REJECTED = "rejected";
         static final String LARGEST = "largest";
         static final String COMPLETED = "completed";
+        static final String WAIT_TIME = "total_wait_time";
+        static final String WAIT_TIME_NANOS = "total_wait_time_in_nanos";
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/threadpool/package-info.java b/server/src/main/java/org/opensearch/threadpool/package-info.java
new file mode 100644
index 0000000000000..f1afdb705d6dd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/threadpool/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base OpenSearch ThreadPool package. */
+package org.opensearch.threadpool;
diff --git a/server/src/main/java/org/opensearch/transport/ActionNotFoundTransportException.java b/server/src/main/java/org/opensearch/transport/ActionNotFoundTransportException.java
index c9d064261cc30..11c1e99a065ac 100644
--- a/server/src/main/java/org/opensearch/transport/ActionNotFoundTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/ActionNotFoundTransportException.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * An exception indicating that a transport action was not found.
  *
- *
+ * @opensearch.internal
  */
 public class ActionNotFoundTransportException extends TransportException {
 
diff --git a/server/src/main/java/org/opensearch/transport/ActionTransportException.java b/server/src/main/java/org/opensearch/transport/ActionTransportException.java
index 387f150710645..fb5dd2c75dc75 100644
--- a/server/src/main/java/org/opensearch/transport/ActionTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/ActionTransportException.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.io.IOException;
 
 /**
  * An action invocation failure.
  *
- *
+ * @opensearch.internal
  */
 public class ActionTransportException extends TransportException {
 
diff --git a/server/src/main/java/org/opensearch/transport/BaseTcpTransportChannel.java b/server/src/main/java/org/opensearch/transport/BaseTcpTransportChannel.java
new file mode 100644
index 0000000000000..14e065d3350c7
--- /dev/null
+++ b/server/src/main/java/org/opensearch/transport/BaseTcpTransportChannel.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.transport;
+
+/**
+ * Base class TcpTransportChannel
+ */
+public abstract class BaseTcpTransportChannel implements TransportChannel {
+    private final TcpChannel channel;
+
+    /**
+     * Constructor.
+     * @param channel tcp channel
+     */
+    public BaseTcpTransportChannel(TcpChannel channel) {
+        this.channel = channel;
+    }
+
+    /**
+     * Returns {@link TcpChannel}
+     * @return TcpChannel
+     */
+    public TcpChannel getChannel() {
+        return channel;
+    }
+
+}
diff --git a/server/src/main/java/org/opensearch/transport/BindTransportException.java b/server/src/main/java/org/opensearch/transport/BindTransportException.java
index 827a45ba0161d..7ef01d2367f11 100644
--- a/server/src/main/java/org/opensearch/transport/BindTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/BindTransportException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * A transport binding failure.
+ *
+ * @opensearch.internal
+ */
 public class BindTransportException extends TransportException {
 
     public BindTransportException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/transport/BytesTransportRequest.java b/server/src/main/java/org/opensearch/transport/BytesTransportRequest.java
index 75e35a1cdcce2..3fd84432639d4 100644
--- a/server/src/main/java/org/opensearch/transport/BytesTransportRequest.java
+++ b/server/src/main/java/org/opensearch/transport/BytesTransportRequest.java
@@ -33,15 +33,17 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
 /**
  * A specialized, bytes only request, that can potentially be optimized on the network
  * layer, specifically for the same large buffer send to several nodes.
+ *
+ * @opensearch.internal
  */
 public class BytesTransportRequest extends TransportRequest {
 
diff --git a/server/src/main/java/org/opensearch/transport/CloseableConnection.java b/server/src/main/java/org/opensearch/transport/CloseableConnection.java
index 7d59279e1bac7..018575e15d8f1 100644
--- a/server/src/main/java/org/opensearch/transport/CloseableConnection.java
+++ b/server/src/main/java/org/opensearch/transport/CloseableConnection.java
@@ -32,11 +32,13 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
 
 /**
  * Abstract Transport.Connection that provides common close logic.
+ *
+ * @opensearch.internal
  */
 public abstract class CloseableConnection implements Transport.Connection {
 
diff --git a/server/src/main/java/org/opensearch/transport/ClusterConnectionManager.java b/server/src/main/java/org/opensearch/transport/ClusterConnectionManager.java
index c44b3cf11c14d..e634323d58269 100644
--- a/server/src/main/java/org/opensearch/transport/ClusterConnectionManager.java
+++ b/server/src/main/java/org/opensearch/transport/ClusterConnectionManager.java
@@ -33,15 +33,15 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRefCounted;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ListenableFuture;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.RunOnce;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.Collections;
 import java.util.Iterator;
@@ -55,6 +55,8 @@
  * This class manages node connections within a cluster. The connection is opened by the underlying transport.
  * Once the connection is opened, this class manages the connection. This includes closing the connection when
  * the connection manager is closed.
+ *
+ * @opensearch.internal
  */
 public class ClusterConnectionManager implements ConnectionManager {
 
diff --git a/server/src/main/java/org/opensearch/transport/CompressibleBytesOutputStream.java b/server/src/main/java/org/opensearch/transport/CompressibleBytesOutputStream.java
index 3d2af65127362..5cb169439a14d 100644
--- a/server/src/main/java/org/opensearch/transport/CompressibleBytesOutputStream.java
+++ b/server/src/main/java/org/opensearch/transport/CompressibleBytesOutputStream.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.io.stream.BytesStream;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.compress.CompressorRegistry;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -55,6 +55,8 @@
  *
  * {@link CompressibleBytesOutputStream#close()} will NOT close the underlying stream. The byte stream passed
  * in the constructor must be closed individually.
+ *
+ * @opensearch.internal
  */
 final class CompressibleBytesOutputStream extends StreamOutput {
 
@@ -66,7 +68,7 @@ final class CompressibleBytesOutputStream extends StreamOutput {
         this.bytesStreamOutput = bytesStreamOutput;
         this.shouldCompress = shouldCompress;
         if (shouldCompress) {
-            this.stream = CompressorFactory.COMPRESSOR.threadLocalOutputStream(Streams.flushOnCloseStream(bytesStreamOutput));
+            this.stream = CompressorRegistry.defaultCompressor().threadLocalOutputStream(Streams.flushOnCloseStream(bytesStreamOutput));
         } else {
             this.stream = bytesStreamOutput;
         }
diff --git a/server/src/main/java/org/opensearch/transport/ConnectTransportException.java b/server/src/main/java/org/opensearch/transport/ConnectTransportException.java
index 5c5ce933647c6..257cb442ffd99 100644
--- a/server/src/main/java/org/opensearch/transport/ConnectTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/ConnectTransportException.java
@@ -33,11 +33,16 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Transport connection exception
+ *
+ * @opensearch.internal
+ */
 public class ConnectTransportException extends ActionTransportException {
 
     private final DiscoveryNode node;
diff --git a/server/src/main/java/org/opensearch/transport/ConnectionManager.java b/server/src/main/java/org/opensearch/transport/ConnectionManager.java
index dfac5acfc9230..10cfc2907098f 100644
--- a/server/src/main/java/org/opensearch/transport/ConnectionManager.java
+++ b/server/src/main/java/org/opensearch/transport/ConnectionManager.java
@@ -32,13 +32,18 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.Closeable;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 
+/**
+ * Transport connection manager.
+ *
+ * @opensearch.internal
+ */
 public interface ConnectionManager extends Closeable {
 
     void addListener(TransportConnectionListener listener);
@@ -71,11 +76,21 @@ void connectToNode(
 
     ConnectionProfile getConnectionProfile();
 
+    /**
+     * Validates a connection
+     *
+     * @opensearch.internal
+     */
     @FunctionalInterface
     interface ConnectionValidator {
         void validate(Transport.Connection connection, ConnectionProfile profile, ActionListener<Void> listener);
     }
 
+    /**
+     * Connection listener for a delegating node
+     *
+     * @opensearch.internal
+     */
     final class DelegatingNodeConnectionListener implements TransportConnectionListener {
 
         private final CopyOnWriteArrayList<TransportConnectionListener> listeners = new CopyOnWriteArrayList<>();
diff --git a/server/src/main/java/org/opensearch/transport/ConnectionProfile.java b/server/src/main/java/org/opensearch/transport/ConnectionProfile.java
index 8ef42436546f1..b9764c0c53f4a 100644
--- a/server/src/main/java/org/opensearch/transport/ConnectionProfile.java
+++ b/server/src/main/java/org/opensearch/transport/ConnectionProfile.java
@@ -48,6 +48,8 @@
 /**
  * A connection profile describes how many connection are established to specific node for each of the available request types.
  * ({@link org.opensearch.transport.TransportRequestOptions.Type}). This allows to tailor a connection towards a specific usage.
+ *
+ * @opensearch.internal
  */
 public final class ConnectionProfile {
 
@@ -100,8 +102,11 @@ public static ConnectionProfile buildDefaultConnectionProfile(Settings settings)
         builder.setCompressionEnabled(TransportSettings.TRANSPORT_COMPRESS.get(settings));
         builder.addConnections(connectionsPerNodeBulk, TransportRequestOptions.Type.BULK);
         builder.addConnections(connectionsPerNodePing, TransportRequestOptions.Type.PING);
-        // if we are not master eligible we don't need a dedicated channel to publish the state
-        builder.addConnections(DiscoveryNode.isMasterNode(settings) ? connectionsPerNodeState : 0, TransportRequestOptions.Type.STATE);
+        // if we are not cluster-manager eligible we don't need a dedicated channel to publish the state
+        builder.addConnections(
+            DiscoveryNode.isClusterManagerNode(settings) ? connectionsPerNodeState : 0,
+            TransportRequestOptions.Type.STATE
+        );
         // if we are not a data-node we don't need any dedicated channels for recovery
         builder.addConnections(DiscoveryNode.isDataNode(settings) ? connectionsPerNodeRecovery : 0, TransportRequestOptions.Type.RECOVERY);
         builder.addConnections(connectionsPerNodeReg, TransportRequestOptions.Type.REG);
@@ -172,6 +177,8 @@ private ConnectionProfile(
 
     /**
      * A builder to build a new {@link ConnectionProfile}
+     *
+     * @opensearch.internal
      */
     public static class Builder {
         private final List<ConnectionTypeHandle> handles = new ArrayList<>();
diff --git a/server/src/main/java/org/opensearch/transport/EmptyTransportResponseHandler.java b/server/src/main/java/org/opensearch/transport/EmptyTransportResponseHandler.java
index b76ede361cada..1691b427ffca1 100644
--- a/server/src/main/java/org/opensearch/transport/EmptyTransportResponseHandler.java
+++ b/server/src/main/java/org/opensearch/transport/EmptyTransportResponseHandler.java
@@ -32,9 +32,15 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 
+/**
+ * Handler for empty transport response
+ *
+ * @opensearch.internal
+ */
 public class EmptyTransportResponseHandler implements TransportResponseHandler<TransportResponse.Empty> {
 
     public static final EmptyTransportResponseHandler INSTANCE_SAME = new EmptyTransportResponseHandler(ThreadPool.Names.SAME);
diff --git a/server/src/main/java/org/opensearch/transport/FutureTransportResponseHandler.java b/server/src/main/java/org/opensearch/transport/FutureTransportResponseHandler.java
index 4d8bca6d99a9a..7d01a36ea12a5 100644
--- a/server/src/main/java/org/opensearch/transport/FutureTransportResponseHandler.java
+++ b/server/src/main/java/org/opensearch/transport/FutureTransportResponseHandler.java
@@ -32,10 +32,13 @@
 
 package org.opensearch.transport;
 
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 
 /**
  * A response handler to be used when all interaction will be done through the {@link TransportFuture}.
+ *
+ * @opensearch.internal
  */
 public abstract class FutureTransportResponseHandler<T extends TransportResponse> implements TransportResponseHandler<T> {
 
diff --git a/server/src/main/java/org/opensearch/transport/Header.java b/server/src/main/java/org/opensearch/transport/Header.java
index 009a362527e9c..a179cfb35288e 100644
--- a/server/src/main/java/org/opensearch/transport/Header.java
+++ b/server/src/main/java/org/opensearch/transport/Header.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -44,6 +44,11 @@
 import java.util.Set;
 import java.util.TreeSet;
 
+/**
+ * Transport Header
+ *
+ * @opensearch.internal
+ */
 public class Header {
 
     private static final String RESPONSE_NAME = "NO_ACTION_NAME_FOR_RESPONSES";
diff --git a/server/src/main/java/org/opensearch/transport/InboundAggregator.java b/server/src/main/java/org/opensearch/transport/InboundAggregator.java
index a6e8ce6e14aa7..e894331f3b64e 100644
--- a/server/src/main/java/org/opensearch/transport/InboundAggregator.java
+++ b/server/src/main/java/org/opensearch/transport/InboundAggregator.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -48,6 +48,11 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+/**
+ * Aggregates inbound data
+ *
+ * @opensearch.internal
+ */
 public class InboundAggregator implements Releasable {
 
     private final Supplier<CircuitBreaker> circuitBreaker;
@@ -234,6 +239,11 @@ private void checkBreaker(final Header header, final int contentLength, final Br
         }
     }
 
+    /**
+     * Internal circuit breaker control
+     *
+     * @opensearch.internal
+     */
     private static class BreakerControl implements Releasable {
 
         private static final int CLOSED = -1;
diff --git a/server/src/main/java/org/opensearch/transport/InboundDecoder.java b/server/src/main/java/org/opensearch/transport/InboundDecoder.java
index bd1d384fd37da..9b94ceabb76a1 100644
--- a/server/src/main/java/org/opensearch/transport/InboundDecoder.java
+++ b/server/src/main/java/org/opensearch/transport/InboundDecoder.java
@@ -33,16 +33,21 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 import java.util.function.Consumer;
 
+/**
+ * Decodes inbound data off the wire
+ *
+ * @opensearch.internal
+ */
 public class InboundDecoder implements Releasable {
 
     static final Object PING = new Object();
@@ -217,7 +222,7 @@ static IllegalStateException ensureVersionCompatibility(Version remoteVersion, V
         // handshake. This looks odd but it's required to establish the connection correctly we check for real compatibility
         // once the connection is established
         final Version compatibilityVersion = isHandshake ? currentVersion.minimumCompatibilityVersion() : currentVersion;
-        if ((currentVersion.equals(Version.V_2_0_0) && remoteVersion.equals(Version.fromId(6079999))) == false
+        if ((currentVersion.onOrAfter(Version.V_2_0_0) && remoteVersion.equals(Version.fromId(6079999))) == false
             && remoteVersion.isCompatible(compatibilityVersion) == false) {
             final Version minCompatibilityVersion = isHandshake ? compatibilityVersion : compatibilityVersion.minimumCompatibilityVersion();
             String msg = "Received " + (isHandshake ? "handshake " : "") + "message from unsupported version: [";
diff --git a/server/src/main/java/org/opensearch/transport/InboundHandler.java b/server/src/main/java/org/opensearch/transport/InboundHandler.java
index 6aa319934b478..c14a53e799319 100644
--- a/server/src/main/java/org/opensearch/transport/InboundHandler.java
+++ b/server/src/main/java/org/opensearch/transport/InboundHandler.java
@@ -37,14 +37,20 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanBuilder;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.channels.TraceableTcpTransportChannel;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.EOFException;
@@ -52,6 +58,11 @@
 import java.net.InetSocketAddress;
 import java.nio.ByteBuffer;
 
+/**
+ * Handler for inbound data
+ *
+ * @opensearch.internal
+ */
 public class InboundHandler {
 
     private static final Logger logger = LogManager.getLogger(InboundHandler.class);
@@ -68,6 +79,8 @@ public class InboundHandler {
 
     private volatile long slowLogThresholdMs = Long.MAX_VALUE;
 
+    private final Tracer tracer;
+
     InboundHandler(
         ThreadPool threadPool,
         OutboundHandler outboundHandler,
@@ -75,7 +88,8 @@ public class InboundHandler {
         TransportHandshaker handshaker,
         TransportKeepAlive keepAlive,
         Transport.RequestHandlers requestHandlers,
-        Transport.ResponseHandlers responseHandlers
+        Transport.ResponseHandlers responseHandlers,
+        Tracer tracer
     ) {
         this.threadPool = threadPool;
         this.outboundHandler = outboundHandler;
@@ -84,6 +98,7 @@ public class InboundHandler {
         this.keepAlive = keepAlive;
         this.requestHandlers = requestHandlers;
         this.responseHandlers = responseHandlers;
+        this.tracer = tracer;
     }
 
     void setMessageListener(TransportMessageListener listener) {
@@ -102,7 +117,6 @@ void inboundMessage(TcpChannel channel, InboundMessage message) throws Exception
         final long startTime = threadPool.relativeTimeInMillis();
         channel.getChannelStats().markAccessed(startTime);
         TransportLogger.logInboundMessage(channel, message);
-
         if (message.isPing()) {
             keepAlive.receiveKeepAlive(channel);
         } else {
@@ -117,7 +131,6 @@ private void messageReceived(TcpChannel channel, InboundMessage message, long st
         final InetSocketAddress remoteAddress = channel.getRemoteAddress();
         final Header header = message.getHeader();
         assert header.needsToReadVariableHeader() == false;
-
         ThreadContext threadContext = threadPool.getThreadContext();
         try (ThreadContext.StoredContext existing = threadContext.stashContext()) {
             // Place the context with the headers from the message
@@ -159,6 +172,7 @@ private void messageReceived(TcpChannel channel, InboundMessage message, long st
                         handleResponse(requestId, remoteAddress, EMPTY_STREAM_INPUT, handler);
                     }
                 }
+
             }
         } finally {
             final long took = threadPool.relativeTimeInMillis() - startTime;
@@ -178,80 +192,89 @@ private <T extends TransportRequest> void handleRequest(TcpChannel channel, Head
         final String action = header.getActionName();
         final long requestId = header.getRequestId();
         final Version version = header.getVersion();
-        if (header.isHandshake()) {
-            messageListener.onRequestReceived(requestId, action);
-            // Cannot short circuit handshakes
-            assert message.isShortCircuit() == false;
-            final StreamInput stream = namedWriteableStream(message.openOrGetStreamInput());
-            assertRemoteVersion(stream, header.getVersion());
-            final TransportChannel transportChannel = new TcpTransportChannel(
-                outboundHandler,
-                channel,
-                action,
-                requestId,
-                version,
-                header.getFeatures(),
-                header.isCompressed(),
-                header.isHandshake(),
-                message.takeBreakerReleaseControl()
-            );
-            try {
-                handshaker.handleHandshake(transportChannel, requestId, stream);
-            } catch (Exception e) {
-                if (Version.CURRENT.isCompatible(header.getVersion())) {
-                    sendErrorResponse(action, transportChannel, e);
-                } else {
-                    logger.warn(
-                        new ParameterizedMessage(
-                            "could not send error response to handshake received on [{}] using wire format version [{}], closing channel",
-                            channel,
-                            header.getVersion()
-                        ),
-                        e
-                    );
-                    channel.close();
-                }
-            }
-        } else {
-            final TransportChannel transportChannel = new TcpTransportChannel(
-                outboundHandler,
-                channel,
-                action,
-                requestId,
-                version,
-                header.getFeatures(),
-                header.isCompressed(),
-                header.isHandshake(),
-                message.takeBreakerReleaseControl()
-            );
-            try {
+        Span span = tracer.startSpan(SpanBuilder.from(action, channel));
+        try (SpanScope spanScope = tracer.withSpanInScope(span)) {
+            if (header.isHandshake()) {
                 messageListener.onRequestReceived(requestId, action);
-                if (message.isShortCircuit()) {
-                    sendErrorResponse(action, transportChannel, message.getException());
-                } else {
-                    final StreamInput stream = namedWriteableStream(message.openOrGetStreamInput());
-                    assertRemoteVersion(stream, header.getVersion());
-                    final RequestHandlerRegistry<T> reg = requestHandlers.getHandler(action);
-                    assert reg != null;
-
-                    final T request = newRequest(requestId, action, stream, reg);
-                    request.remoteAddress(new TransportAddress(channel.getRemoteAddress()));
-                    checkStreamIsFullyConsumed(requestId, action, stream);
-
-                    final String executor = reg.getExecutor();
-                    if (ThreadPool.Names.SAME.equals(executor)) {
-                        try {
-                            reg.processMessageReceived(request, transportChannel);
-                        } catch (Exception e) {
-                            sendErrorResponse(reg.getAction(), transportChannel, e);
-                        }
+                // Cannot short circuit handshakes
+                assert message.isShortCircuit() == false;
+                final StreamInput stream = namedWriteableStream(message.openOrGetStreamInput());
+                assertRemoteVersion(stream, header.getVersion());
+                final TcpTransportChannel transportChannel = new TcpTransportChannel(
+                    outboundHandler,
+                    channel,
+                    action,
+                    requestId,
+                    version,
+                    header.getFeatures(),
+                    header.isCompressed(),
+                    header.isHandshake(),
+                    message.takeBreakerReleaseControl()
+                );
+                TransportChannel traceableTransportChannel = TraceableTcpTransportChannel.create(transportChannel, span, tracer);
+                try {
+                    handshaker.handleHandshake(traceableTransportChannel, requestId, stream);
+                } catch (Exception e) {
+                    if (Version.CURRENT.isCompatible(header.getVersion())) {
+                        sendErrorResponse(action, traceableTransportChannel, e);
                     } else {
-                        threadPool.executor(executor).execute(new RequestHandler<>(reg, request, transportChannel));
+                        logger.warn(
+                            new ParameterizedMessage(
+                                "could not send error response to handshake received on [{}] using wire format version [{}], closing channel",
+                                channel,
+                                header.getVersion()
+                            ),
+                            e
+                        );
+                        channel.close();
                     }
                 }
-            } catch (Exception e) {
-                sendErrorResponse(action, transportChannel, e);
+            } else {
+                final TcpTransportChannel transportChannel = new TcpTransportChannel(
+                    outboundHandler,
+                    channel,
+                    action,
+                    requestId,
+                    version,
+                    header.getFeatures(),
+                    header.isCompressed(),
+                    header.isHandshake(),
+                    message.takeBreakerReleaseControl()
+                );
+                TransportChannel traceableTransportChannel = TraceableTcpTransportChannel.create(transportChannel, span, tracer);
+                try {
+                    messageListener.onRequestReceived(requestId, action);
+                    if (message.isShortCircuit()) {
+                        sendErrorResponse(action, traceableTransportChannel, message.getException());
+                    } else {
+                        final StreamInput stream = namedWriteableStream(message.openOrGetStreamInput());
+                        assertRemoteVersion(stream, header.getVersion());
+                        final RequestHandlerRegistry<T> reg = requestHandlers.getHandler(action);
+                        assert reg != null;
+
+                        final T request = newRequest(requestId, action, stream, reg);
+                        request.remoteAddress(new TransportAddress(channel.getRemoteAddress()));
+                        checkStreamIsFullyConsumed(requestId, action, stream);
+
+                        final String executor = reg.getExecutor();
+                        if (ThreadPool.Names.SAME.equals(executor)) {
+                            try {
+                                reg.processMessageReceived(request, traceableTransportChannel);
+                            } catch (Exception e) {
+                                sendErrorResponse(reg.getAction(), traceableTransportChannel, e);
+                            }
+                        } else {
+                            threadPool.executor(executor).execute(new RequestHandler<>(reg, request, traceableTransportChannel));
+                        }
+                    }
+                } catch (Exception e) {
+                    sendErrorResponse(action, traceableTransportChannel, e);
+                }
             }
+        } catch (Exception e) {
+            span.setError(e);
+            span.endSpan();
+            throw e;
         }
     }
 
@@ -427,6 +450,11 @@ static void assertRemoteVersion(StreamInput in, Version version) {
         assert version.equals(in.getVersion()) : "Stream version [" + in.getVersion() + "] does not match version [" + version + "]";
     }
 
+    /**
+     * Internal request handler
+     *
+     * @opensearch.internal
+     */
     private static class RequestHandler<T extends TransportRequest> extends AbstractRunnable {
         private final RequestHandlerRegistry<T> reg;
         private final T request;
diff --git a/server/src/main/java/org/opensearch/transport/InboundMessage.java b/server/src/main/java/org/opensearch/transport/InboundMessage.java
index 7835771ec4d8e..a1ed682ff7d7f 100644
--- a/server/src/main/java/org/opensearch/transport/InboundMessage.java
+++ b/server/src/main/java/org/opensearch/transport/InboundMessage.java
@@ -33,13 +33,18 @@
 package org.opensearch.transport;
 
 import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Inbound data as a message
+ *
+ * @opensearch.internal
+ */
 public class InboundMessage implements Releasable {
 
     private final Header header;
diff --git a/server/src/main/java/org/opensearch/transport/InboundPipeline.java b/server/src/main/java/org/opensearch/transport/InboundPipeline.java
index 924b9f995eccf..dd4690e5e6abf 100644
--- a/server/src/main/java/org/opensearch/transport/InboundPipeline.java
+++ b/server/src/main/java/org/opensearch/transport/InboundPipeline.java
@@ -33,12 +33,12 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
 
 import java.io.IOException;
 import java.util.ArrayDeque;
@@ -48,6 +48,11 @@
 import java.util.function.LongSupplier;
 import java.util.function.Supplier;
 
+/**
+ * Pipeline for receiving inbound messages
+ *
+ * @opensearch.internal
+ */
 public class InboundPipeline implements Releasable {
 
     private static final ThreadLocal<ArrayList<Object>> fragmentList = ThreadLocal.withInitial(ArrayList::new);
diff --git a/server/src/main/java/org/opensearch/transport/NetworkMessage.java b/server/src/main/java/org/opensearch/transport/NetworkMessage.java
index 8dd6c740d72e4..f02d664b65929 100644
--- a/server/src/main/java/org/opensearch/transport/NetworkMessage.java
+++ b/server/src/main/java/org/opensearch/transport/NetworkMessage.java
@@ -32,12 +32,14 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.Writeable;
 
 /**
  * Represents a transport message sent over the network. Subclasses implement serialization and
  * deserialization.
+ *
+ * @opensearch.internal
  */
 public abstract class NetworkMessage {
 
diff --git a/server/src/main/java/org/opensearch/transport/NoSeedNodeLeftException.java b/server/src/main/java/org/opensearch/transport/NoSeedNodeLeftException.java
index fb3978b346275..66365b4c529cb 100644
--- a/server/src/main/java/org/opensearch/transport/NoSeedNodeLeftException.java
+++ b/server/src/main/java/org/opensearch/transport/NoSeedNodeLeftException.java
@@ -33,12 +33,14 @@
 package org.opensearch.transport;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * Thrown after failed to connect to all seed nodes of the remote cluster.
+ *
+ * @opensearch.internal
  */
 public class NoSeedNodeLeftException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/transport/NoSuchRemoteClusterException.java b/server/src/main/java/org/opensearch/transport/NoSuchRemoteClusterException.java
index 9a91d19d70f5d..ee3b11172cb30 100644
--- a/server/src/main/java/org/opensearch/transport/NoSuchRemoteClusterException.java
+++ b/server/src/main/java/org/opensearch/transport/NoSuchRemoteClusterException.java
@@ -33,13 +33,15 @@
 package org.opensearch.transport;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * An exception that remote cluster is missing or
  * connectivity to the remote connection is failing
+ *
+ * @opensearch.internal
  */
 public final class NoSuchRemoteClusterException extends ResourceNotFoundException {
 
diff --git a/server/src/main/java/org/opensearch/transport/NodeDisconnectedException.java b/server/src/main/java/org/opensearch/transport/NodeDisconnectedException.java
index d43fe105dcd43..93379e6023b44 100644
--- a/server/src/main/java/org/opensearch/transport/NodeDisconnectedException.java
+++ b/server/src/main/java/org/opensearch/transport/NodeDisconnectedException.java
@@ -33,10 +33,15 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a node disconnects
+ *
+ * @opensearch.internal
+ */
 public class NodeDisconnectedException extends ConnectTransportException {
 
     public NodeDisconnectedException(DiscoveryNode node, String action) {
diff --git a/server/src/main/java/org/opensearch/transport/NodeNotConnectedException.java b/server/src/main/java/org/opensearch/transport/NodeNotConnectedException.java
index 134c1f7c08a3c..915633273bd6e 100644
--- a/server/src/main/java/org/opensearch/transport/NodeNotConnectedException.java
+++ b/server/src/main/java/org/opensearch/transport/NodeNotConnectedException.java
@@ -33,14 +33,14 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * An exception indicating that a message is sent to a node that is not connected.
  *
- *
+ * @opensearch.internal
  */
 public class NodeNotConnectedException extends ConnectTransportException {
 
diff --git a/server/src/main/java/org/opensearch/transport/NodeShouldNotConnectException.java b/server/src/main/java/org/opensearch/transport/NodeShouldNotConnectException.java
index 263f4311b399f..24fb8e1269d56 100644
--- a/server/src/main/java/org/opensearch/transport/NodeShouldNotConnectException.java
+++ b/server/src/main/java/org/opensearch/transport/NodeShouldNotConnectException.java
@@ -33,10 +33,15 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if a node should not disconnect
+ *
+ * @opensearch.internal
+ */
 public class NodeShouldNotConnectException extends NodeNotConnectedException {
 
     public NodeShouldNotConnectException(DiscoveryNode fromNode, DiscoveryNode node) {
diff --git a/server/src/main/java/org/opensearch/transport/NotSerializableTransportException.java b/server/src/main/java/org/opensearch/transport/NotSerializableTransportException.java
index 91003dc07059e..487dc113743f8 100644
--- a/server/src/main/java/org/opensearch/transport/NotSerializableTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/NotSerializableTransportException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Exception thrown if data is not serializable
+ *
+ * @opensearch.internal
+ */
 public class NotSerializableTransportException extends TransportException {
 
     public NotSerializableTransportException(Throwable t) {
diff --git a/server/src/main/java/org/opensearch/transport/OutboundHandler.java b/server/src/main/java/org/opensearch/transport/OutboundHandler.java
index 4b9ce7eabb6ce..b83dbdd0effe4 100644
--- a/server/src/main/java/org/opensearch/transport/OutboundHandler.java
+++ b/server/src/main/java/org/opensearch/transport/OutboundHandler.java
@@ -36,25 +36,31 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.NotifyOnceListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.transport.NetworkExceptionHelper;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
 import java.util.Set;
 
+/**
+ * Outbound data handler
+ *
+ * @opensearch.internal
+ */
 final class OutboundHandler {
 
     private static final Logger logger = LogManager.getLogger(OutboundHandler.class);
@@ -207,6 +213,11 @@ void setMessageListener(TransportMessageListener listener) {
         }
     }
 
+    /**
+     * Internal message serializer
+     *
+     * @opensearch.internal
+     */
     private static class MessageSerializer implements CheckedSupplier<BytesReference, IOException>, Releasable {
 
         private final OutboundMessage message;
diff --git a/server/src/main/java/org/opensearch/transport/OutboundMessage.java b/server/src/main/java/org/opensearch/transport/OutboundMessage.java
index 51d0da2c25439..358655288f849 100644
--- a/server/src/main/java/org/opensearch/transport/OutboundMessage.java
+++ b/server/src/main/java/org/opensearch/transport/OutboundMessage.java
@@ -32,17 +32,22 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Set;
 
+/**
+ * Outbound data as a message
+ *
+ * @opensearch.internal
+ */
 abstract class OutboundMessage extends NetworkMessage {
 
     private final Writeable message;
@@ -112,6 +117,11 @@ protected BytesReference writeMessage(CompressibleBytesOutputStream stream) thro
         }
     }
 
+    /**
+     * Internal outbound message request
+     *
+     * @opensearch.internal
+     */
     static class Request extends OutboundMessage {
 
         private final String[] features;
@@ -153,6 +163,11 @@ private static byte setStatus(boolean compress, boolean isHandshake, Writeable m
         }
     }
 
+    /**
+     * Internal message response
+     *
+     * @opensearch.internal
+     */
     static class Response extends OutboundMessage {
 
         private final Set<String> features;
diff --git a/server/src/main/java/org/opensearch/transport/PlainTransportFuture.java b/server/src/main/java/org/opensearch/transport/PlainTransportFuture.java
index 097b5bd7dd573..ff9ca8b189904 100644
--- a/server/src/main/java/org/opensearch/transport/PlainTransportFuture.java
+++ b/server/src/main/java/org/opensearch/transport/PlainTransportFuture.java
@@ -34,14 +34,20 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.concurrent.BaseFuture;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
+/**
+ * Future for transporting data
+ *
+ * @opensearch.internal
+ */
 public class PlainTransportFuture<V extends TransportResponse> extends BaseFuture<V>
     implements
         TransportFuture<V>,
diff --git a/server/src/main/java/org/opensearch/transport/ProxyConnectionStrategy.java b/server/src/main/java/org/opensearch/transport/ProxyConnectionStrategy.java
index 46ae93b62ebd6..c8c11a0a48d3c 100644
--- a/server/src/main/java/org/opensearch/transport/ProxyConnectionStrategy.java
+++ b/server/src/main/java/org/opensearch/transport/ProxyConnectionStrategy.java
@@ -35,19 +35,19 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -60,6 +60,11 @@
 
 import static org.opensearch.common.settings.Setting.intSetting;
 
+/**
+ * Connect through a proxy
+ *
+ * @opensearch.internal
+ */
 public class ProxyConnectionStrategy extends RemoteConnectionStrategy {
 
     /**
@@ -339,6 +344,11 @@ private static TransportAddress resolveAddress(String address) {
         return new TransportAddress(parseConfiguredAddress(address));
     }
 
+    /**
+     * Contains information about the proxy mode
+     *
+     * @opensearch.internal
+     */
     public static class ProxyModeInfo implements RemoteConnectionInfo.ModeInfo {
 
         private final String address;
diff --git a/server/src/main/java/org/opensearch/transport/ReceiveTimeoutTransportException.java b/server/src/main/java/org/opensearch/transport/ReceiveTimeoutTransportException.java
index eb14434c951b3..a2d48373cd43d 100644
--- a/server/src/main/java/org/opensearch/transport/ReceiveTimeoutTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/ReceiveTimeoutTransportException.java
@@ -33,10 +33,15 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown when receiving a timeout
+ *
+ * @opensearch.internal
+ */
 public class ReceiveTimeoutTransportException extends ActionTransportException {
 
     public ReceiveTimeoutTransportException(DiscoveryNode node, String action, String msg) {
diff --git a/server/src/main/java/org/opensearch/transport/RemoteClusterAware.java b/server/src/main/java/org/opensearch/transport/RemoteClusterAware.java
index d8641bc6f536d..ad8f59f7af6aa 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteClusterAware.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteClusterAware.java
@@ -47,6 +47,8 @@
 
 /**
  * Base class for all services and components that need up-to-date information about the registered remote clusters
+ *
+ * @opensearch.internal
  */
 public abstract class RemoteClusterAware {
 
diff --git a/server/src/main/java/org/opensearch/transport/RemoteClusterAwareClient.java b/server/src/main/java/org/opensearch/transport/RemoteClusterAwareClient.java
index 17dfad6a1b9ac..0389c76d1ade6 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteClusterAwareClient.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteClusterAwareClient.java
@@ -31,17 +31,22 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.client.Client;
 import org.opensearch.client.support.AbstractClient;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.threadpool.ThreadPool;
 
+/**
+ * Client that is aware of remote clusters
+ *
+ * @opensearch.internal
+ */
 final class RemoteClusterAwareClient extends AbstractClient {
 
     private final TransportService service;
diff --git a/server/src/main/java/org/opensearch/transport/RemoteClusterAwareRequest.java b/server/src/main/java/org/opensearch/transport/RemoteClusterAwareRequest.java
index aa2da7ac5c288..727519f6ba9e5 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteClusterAwareRequest.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteClusterAwareRequest.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.cluster.node.DiscoveryNode;
 
+/**
+ * Request for remote clusters
+ *
+ * @opensearch.internal
+ */
 public interface RemoteClusterAwareRequest {
 
     /**
diff --git a/server/src/main/java/org/opensearch/transport/RemoteClusterConnection.java b/server/src/main/java/org/opensearch/transport/RemoteClusterConnection.java
index ff4a2cd7701f8..1599c4cb75517 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteClusterConnection.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteClusterConnection.java
@@ -31,18 +31,18 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.state.ClusterStateAction;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.action.support.ContextPreservingActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -61,6 +61,8 @@
  * In the case of a disconnection, this class will issue a re-connect task to establish at most
  * {@link SniffConnectionStrategy#REMOTE_CONNECTIONS_PER_CLUSTER} until either all eligible nodes are exhausted or the maximum number of
  * connections per cluster has been reached.
+ *
+ * @opensearch.internal
  */
 final class RemoteClusterConnection implements Closeable {
 
diff --git a/server/src/main/java/org/opensearch/transport/RemoteClusterService.java b/server/src/main/java/org/opensearch/transport/RemoteClusterService.java
index 8791a322b2c59..35691cc5f8a1e 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteClusterService.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteClusterService.java
@@ -34,22 +34,21 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.GroupedActionListener;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -63,7 +62,6 @@
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -74,6 +72,8 @@
 
 /**
  * Basic service for accessing remote clusters via gateway nodes
+ *
+ * @opensearch.internal
  */
 public final class RemoteClusterService extends RemoteClusterAware implements Closeable {
 
@@ -326,35 +326,23 @@ synchronized void updateRemoteCluster(String clusterAlias, Settings newSettings,
     }
 
     /**
-     * Connects to all remote clusters in a blocking fashion. This should be called on node startup to establish an initial connection
+     * Connects to all remote clusters in a non-blocking fashion. This should be called on node startup to establish an initial connection
      * to all configured seed nodes.
      */
-    void initializeRemoteClusters() {
-        final TimeValue timeValue = REMOTE_INITIAL_CONNECTION_TIMEOUT_SETTING.get(settings);
-        final PlainActionFuture<Collection<Void>> future = new PlainActionFuture<>();
+    void initializeRemoteClusters(ActionListener<Void> listener) {
         Set<String> enabledClusters = RemoteClusterAware.getEnabledRemoteClusters(settings);
-
         if (enabledClusters.isEmpty()) {
+            listener.onResponse(null);
             return;
         }
 
-        GroupedActionListener<Void> listener = new GroupedActionListener<>(future, enabledClusters.size());
-        for (String clusterAlias : enabledClusters) {
-            updateRemoteCluster(clusterAlias, settings, listener);
-        }
-
-        if (enabledClusters.isEmpty()) {
-            future.onResponse(null);
-        }
+        GroupedActionListener<Void> groupListener = new GroupedActionListener<>(
+            ActionListener.wrap(r -> listener.onResponse(null), listener::onFailure),
+            enabledClusters.size()
+        );
 
-        try {
-            future.get(timeValue.millis(), TimeUnit.MILLISECONDS);
-        } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-        } catch (TimeoutException ex) {
-            logger.warn("failed to connect to remote clusters within {}", timeValue.toString());
-        } catch (Exception e) {
-            throw new IllegalStateException("failed to connect to remote clusters", e);
+        for (String clusterAlias : enabledClusters) {
+            updateRemoteCluster(clusterAlias, settings, groupListener);
         }
     }
 
@@ -434,6 +422,11 @@ Collection<RemoteClusterConnection> getConnections() {
         return remoteClusters.values();
     }
 
+    /**
+     * Internal class to hold cluster alias and key and track a remote connection
+     *
+     * @opensearch.internal
+     */
     private static class RemoteConnectionEnabled<T> implements Setting.Validator<T> {
 
         private final String clusterAlias;
diff --git a/server/src/main/java/org/opensearch/transport/RemoteConnectionInfo.java b/server/src/main/java/org/opensearch/transport/RemoteConnectionInfo.java
index c23287de4e444..029b44c548b0e 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteConnectionInfo.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteConnectionInfo.java
@@ -33,13 +33,13 @@
 package org.opensearch.transport;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -54,6 +54,8 @@
 /**
  * This class encapsulates all remote cluster information to be rendered on
  * {@code _remote/info} requests.
+ *
+ * @opensearch.internal
  */
 public final class RemoteConnectionInfo implements ToXContentFragment, Writeable {
 
@@ -220,6 +222,11 @@ public int hashCode() {
         return Objects.hash(modeInfo, initialConnectionTimeout, clusterAlias, skipUnavailable);
     }
 
+    /**
+     * Mode information
+     *
+     * @opensearch.internal
+     */
     public interface ModeInfo extends ToXContentFragment, Writeable {
 
         boolean isConnected();
diff --git a/server/src/main/java/org/opensearch/transport/RemoteConnectionManager.java b/server/src/main/java/org/opensearch/transport/RemoteConnectionManager.java
index 67ca7e9c753ce..bd646f10df517 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteConnectionManager.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteConnectionManager.java
@@ -32,8 +32,8 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.action.ActionListener;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -42,6 +42,11 @@
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 
+/**
+ * Manager for connecting to remote nodes
+ *
+ * @opensearch.internal
+ */
 public class RemoteConnectionManager implements ConnectionManager {
 
     private final String clusterAlias;
diff --git a/server/src/main/java/org/opensearch/transport/RemoteConnectionStrategy.java b/server/src/main/java/org/opensearch/transport/RemoteConnectionStrategy.java
index 3903baff3a9bb..f0b37c617725e 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteConnectionStrategy.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteConnectionStrategy.java
@@ -36,16 +36,16 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ContextPreservingActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -68,6 +68,11 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+/**
+ * Strategy to connect to remote nodes
+ *
+ * @opensearch.internal
+ */
 public abstract class RemoteConnectionStrategy implements TransportConnectionListener, Closeable {
 
     enum ConnectionStrategy {
@@ -417,6 +422,11 @@ private boolean connectionProfileChanged(ConnectionProfile oldProfile, Connectio
             || Objects.equals(oldProfile.getPingInterval(), newProfile.getPingInterval()) == false;
     }
 
+    /**
+     * Internal strategy validation object
+     *
+     * @opensearch.internal
+     */
     static class StrategyValidator<T> implements Setting.Validator<T> {
 
         private final String key;
diff --git a/server/src/main/java/org/opensearch/transport/RemoteTransportException.java b/server/src/main/java/org/opensearch/transport/RemoteTransportException.java
index b07cada0edb1b..de3d6bb9d775e 100644
--- a/server/src/main/java/org/opensearch/transport/RemoteTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/RemoteTransportException.java
@@ -33,8 +33,8 @@
 package org.opensearch.transport;
 
 import org.opensearch.OpenSearchWrapperException;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
 
 import java.io.IOException;
 
@@ -42,7 +42,7 @@
  * A remote exception for an action. A wrapper exception around the actual remote cause and does not fill the
  * stack trace.
  *
- *
+ * @opensearch.internal
  */
 public class RemoteTransportException extends ActionTransportException implements OpenSearchWrapperException {
 
diff --git a/server/src/main/java/org/opensearch/transport/RequestHandlerRegistry.java b/server/src/main/java/org/opensearch/transport/RequestHandlerRegistry.java
index dcb021531f0ac..98c182c562928 100644
--- a/server/src/main/java/org/opensearch/transport/RequestHandlerRegistry.java
+++ b/server/src/main/java/org/opensearch/transport/RequestHandlerRegistry.java
@@ -32,10 +32,11 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
@@ -43,7 +44,12 @@
 
 import java.io.IOException;
 
-public class RequestHandlerRegistry<Request extends TransportRequest> {
+/**
+ * Registry for OpenSearch RequestHandlers
+ *
+ * @opensearch.internal
+ */
+public final class RequestHandlerRegistry<Request extends TransportRequest> {
 
     private final String action;
     private final TransportRequestHandler<Request> handler;
@@ -81,16 +87,18 @@ public Request newRequest(StreamInput in) throws IOException {
 
     public void processMessageReceived(Request request, TransportChannel channel) throws Exception {
         final Task task = taskManager.register(channel.getChannelType(), action, request);
+        ThreadContext.StoredContext contextToRestore = taskManager.taskExecutionStarted(task);
+
         Releasable unregisterTask = () -> taskManager.unregister(task);
         try {
-            if (channel instanceof TcpTransportChannel && task instanceof CancellableTask) {
+            if (channel instanceof BaseTcpTransportChannel && task instanceof CancellableTask) {
                 if (request instanceof ShardSearchRequest) {
                     // on receiving request, update the inbound network time to reflect time spent in transit over the network
                     ((ShardSearchRequest) request).setInboundNetworkTime(
                         Math.max(0, System.currentTimeMillis() - ((ShardSearchRequest) request).getInboundNetworkTime())
                     );
                 }
-                final TcpChannel tcpChannel = ((TcpTransportChannel) channel).getChannel();
+                final TcpChannel tcpChannel = ((BaseTcpTransportChannel) channel).getChannel();
                 final Releasable stopTracking = taskManager.startTrackingCancellableChannelTask(tcpChannel, (CancellableTask) task);
                 unregisterTask = Releasables.wrap(unregisterTask, stopTracking);
             }
@@ -99,6 +107,7 @@ public void processMessageReceived(Request request, TransportChannel channel) th
             unregisterTask = null;
         } finally {
             Releasables.close(unregisterTask);
+            contextToRestore.restore();
         }
     }
 
diff --git a/server/src/main/java/org/opensearch/transport/ResponseHandlerFailureTransportException.java b/server/src/main/java/org/opensearch/transport/ResponseHandlerFailureTransportException.java
index 984235738a45d..8eb31b3593b1b 100644
--- a/server/src/main/java/org/opensearch/transport/ResponseHandlerFailureTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/ResponseHandlerFailureTransportException.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
 /**
  * A failure to handle the response of a transaction action.
+ *
+ * @opensearch.internal
  */
 public class ResponseHandlerFailureTransportException extends TransportException {
 
diff --git a/server/src/main/java/org/opensearch/transport/SendRequestTransportException.java b/server/src/main/java/org/opensearch/transport/SendRequestTransportException.java
index 5cf079ea9872c..a70c8d3361ba2 100644
--- a/server/src/main/java/org/opensearch/transport/SendRequestTransportException.java
+++ b/server/src/main/java/org/opensearch/transport/SendRequestTransportException.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.OpenSearchWrapperException;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown when an error occurs while sending a request
+ *
+ * @opensearch.internal
+ */
 public class SendRequestTransportException extends ActionTransportException implements OpenSearchWrapperException {
 
     public SendRequestTransportException(DiscoveryNode node, String action, Throwable cause) {
diff --git a/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java b/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
index 5d2b2d3ac684f..07ba96b135189 100644
--- a/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
+++ b/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
@@ -33,9 +33,7 @@
 package org.opensearch.transport;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.admin.cluster.state.ClusterStateAction;
 import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
@@ -44,17 +42,19 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -74,6 +74,11 @@
 
 import static org.opensearch.common.settings.Setting.intSetting;
 
+/**
+ * Sniff for initial seed nodes
+ *
+ * @opensearch.internal
+ */
 public class SniffConnectionStrategy extends RemoteConnectionStrategy {
 
     /**
@@ -136,7 +141,7 @@ public class SniffConnectionStrategy extends RemoteConnectionStrategy {
     static final int CHANNELS_PER_CONNECTION = 6;
 
     private static final Predicate<DiscoveryNode> DEFAULT_NODE_PREDICATE = (node) -> Version.CURRENT.isCompatible(node.getVersion())
-        && (node.isMasterNode() == false || node.isDataNode() || node.isIngestNode());
+        && (node.isClusterManagerNode() == false || node.isDataNode() || node.isIngestNode());
 
     private final List<String> configuredSeedNodes;
     private final List<Supplier<DiscoveryNode>> seedNodes;
@@ -392,7 +397,7 @@ public ClusterStateResponse read(StreamInput in) throws IOException {
 
         @Override
         public void handleResponse(ClusterStateResponse response) {
-            handleNodes(response.getState().nodes().getNodes().valuesIt());
+            handleNodes(response.getState().nodes().getNodes().values().iterator());
         }
 
         private void handleNodes(Iterator<DiscoveryNode> nodesIter) {
@@ -556,6 +561,11 @@ private boolean proxyChanged(String oldProxy, String newProxy) {
         return Objects.equals(oldProxy, newProxy) == false;
     }
 
+    /**
+     * Information about the sniff mode
+     *
+     * @opensearch.internal
+     */
     public static class SniffModeInfo implements RemoteConnectionInfo.ModeInfo {
 
         final List<String> seedNodes;
diff --git a/server/src/main/java/org/opensearch/transport/StatsTracker.java b/server/src/main/java/org/opensearch/transport/StatsTracker.java
index a97a9c6a9374b..5548d2d558ae2 100644
--- a/server/src/main/java/org/opensearch/transport/StatsTracker.java
+++ b/server/src/main/java/org/opensearch/transport/StatsTracker.java
@@ -36,7 +36,12 @@
 
 import java.util.concurrent.atomic.LongAdder;
 
-public class StatsTracker {
+/**
+ * Tracks transport statistics
+ *
+ * @opensearch.internal
+ */
+public final class StatsTracker {
 
     private final LongAdder bytesRead = new LongAdder();
     private final LongAdder messagesReceived = new LongAdder();
diff --git a/server/src/main/java/org/opensearch/transport/TaskTransportChannel.java b/server/src/main/java/org/opensearch/transport/TaskTransportChannel.java
index 5faf12c3b991f..052611317f174 100644
--- a/server/src/main/java/org/opensearch/transport/TaskTransportChannel.java
+++ b/server/src/main/java/org/opensearch/transport/TaskTransportChannel.java
@@ -34,9 +34,15 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
+/**
+ * Transport channel for tasks
+ *
+ * @opensearch.internal
+ */
 public class TaskTransportChannel implements TransportChannel {
 
     private final TransportChannel channel;
diff --git a/server/src/main/java/org/opensearch/transport/TcpChannel.java b/server/src/main/java/org/opensearch/transport/TcpChannel.java
index 1b07c963890d6..eac137ec30f1a 100644
--- a/server/src/main/java/org/opensearch/transport/TcpChannel.java
+++ b/server/src/main/java/org/opensearch/transport/TcpChannel.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.net.InetSocketAddress;
 
@@ -43,6 +43,8 @@
  * This is a tcp channel representing a single channel connection to another node. It is the base channel
  * abstraction used by the {@link TcpTransport} and {@link TransportService}. All tcp transport
  * implementations must return channels that adhere to the required method contracts.
+ *
+ * @opensearch.internal
  */
 public interface TcpChannel extends CloseableChannel {
 
@@ -94,6 +96,11 @@ public interface TcpChannel extends CloseableChannel {
      */
     ChannelStats getChannelStats();
 
+    /**
+     * Channel statistics
+     *
+     * @opensearch.internal
+     */
     class ChannelStats {
 
         private volatile long lastAccessedTime;
diff --git a/server/src/main/java/org/opensearch/transport/TcpHeader.java b/server/src/main/java/org/opensearch/transport/TcpHeader.java
index 514ebfff6f8f6..997fa5bc52db0 100644
--- a/server/src/main/java/org/opensearch/transport/TcpHeader.java
+++ b/server/src/main/java/org/opensearch/transport/TcpHeader.java
@@ -34,10 +34,15 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
+/**
+ * Header for TCP messages
+ *
+ * @opensearch.internal
+ */
 public class TcpHeader {
 
     public static final Version VERSION_WITH_HEADER_SIZE = LegacyESVersion.V_7_6_0;
diff --git a/server/src/main/java/org/opensearch/transport/TcpServerChannel.java b/server/src/main/java/org/opensearch/transport/TcpServerChannel.java
index fa3d6499d7d62..7d61b8c7d699c 100644
--- a/server/src/main/java/org/opensearch/transport/TcpServerChannel.java
+++ b/server/src/main/java/org/opensearch/transport/TcpServerChannel.java
@@ -40,6 +40,8 @@
  * This is a tcp channel representing a server channel listening for new connections. It is the server
  * channel abstraction used by the {@link TcpTransport} and {@link TransportService}. All tcp transport
  * implementations must return server channels that adhere to the required method contracts.
+ *
+ * @opensearch.internal
  */
 public interface TcpServerChannel extends CloseableChannel {
 
diff --git a/server/src/main/java/org/opensearch/transport/TcpTransport.java b/server/src/main/java/org/opensearch/transport/TcpTransport.java
index c2a0584721148..d0e6516973382 100644
--- a/server/src/main/java/org/opensearch/transport/TcpTransport.java
+++ b/server/src/main/java/org/opensearch/transport/TcpTransport.java
@@ -31,25 +31,16 @@
 
 package org.opensearch.transport;
 
-import com.carrotsearch.hppc.IntHashSet;
-import com.carrotsearch.hppc.IntSet;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ThreadedActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.common.metrics.MeanMetric;
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.network.NetworkAddress;
@@ -57,19 +48,27 @@
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.transport.PortsRange;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.CountDown;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.node.Node;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -109,6 +108,11 @@
 import static org.opensearch.common.transport.NetworkExceptionHelper.isConnectException;
 import static org.opensearch.common.util.concurrent.ConcurrentCollections.newConcurrentMap;
 
+/**
+ * The TCP Transport layer
+ *
+ * @opensearch.internal
+ */
 public abstract class TcpTransport extends AbstractLifecycleComponent implements Transport {
     private static final Logger logger = LogManager.getLogger(TcpTransport.class);
 
@@ -156,7 +160,8 @@ public TcpTransport(
         PageCacheRecycler pageCacheRecycler,
         CircuitBreakerService circuitBreakerService,
         NamedWriteableRegistry namedWriteableRegistry,
-        NetworkService networkService
+        NetworkService networkService,
+        Tracer tracer
     ) {
         this.settings = settings;
         this.profileSettings = getProfileSettings(settings);
@@ -205,7 +210,8 @@ public TcpTransport(
             handshaker,
             keepAlive,
             requestHandlers,
-            responseHandlers
+            responseHandlers,
+            tracer
         );
     }
 
@@ -239,6 +245,11 @@ public void setSlowLogThreshold(TimeValue slowLogThreshold) {
         inboundHandler.setSlowLogThreshold(slowLogThreshold);
     }
 
+    /**
+     * List of node connection channels
+     *
+     * @opensearch.internal
+     */
     public final class NodeChannels extends CloseableConnection {
         private final Map<TransportRequestOptions.Type, ConnectionProfile.ConnectionTypeHandle> typeMapping;
         private final List<TcpChannel> channels;
@@ -514,12 +525,12 @@ static int resolvePublishPort(ProfileSettings profileSettings, List<InetSocketAd
 
         // if no matching boundAddress found, check if there is a unique port for all bound addresses
         if (publishPort < 0) {
-            final IntSet ports = new IntHashSet();
+            final Set<Integer> ports = new HashSet<>();
             for (InetSocketAddress boundAddress : boundAddresses) {
                 ports.add(boundAddress.getPort());
             }
             if (ports.size() == 1) {
-                publishPort = ports.iterator().next().value;
+                publishPort = ports.iterator().next();
             }
         }
 
@@ -867,6 +878,8 @@ private static boolean bufferStartsWith(BytesReference buffer, String method) {
     /**
      * A helper exception to mark an incoming connection as potentially being HTTP
      * so an appropriate error code can be returned
+     *
+     * @opensearch.internal
      */
     public static class HttpRequestOnTransportException extends OpenSearchException {
 
diff --git a/server/src/main/java/org/opensearch/transport/TcpTransportChannel.java b/server/src/main/java/org/opensearch/transport/TcpTransportChannel.java
index 9c91cd3df8c89..a7bedcf93e129 100644
--- a/server/src/main/java/org/opensearch/transport/TcpTransportChannel.java
+++ b/server/src/main/java/org/opensearch/transport/TcpTransportChannel.java
@@ -34,17 +34,22 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.search.query.QuerySearchResult;
 
 import java.io.IOException;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-public final class TcpTransportChannel implements TransportChannel {
+/**
+ * Channel for a TCP connection
+ *
+ * @opensearch.internal
+ */
+public final class TcpTransportChannel extends BaseTcpTransportChannel {
 
     private final AtomicBoolean released = new AtomicBoolean();
     private final OutboundHandler outboundHandler;
-    private final TcpChannel channel;
     private final String action;
     private final long requestId;
     private final Version version;
@@ -64,9 +69,9 @@ public final class TcpTransportChannel implements TransportChannel {
         boolean isHandshake,
         Releasable breakerRelease
     ) {
+        super(channel);
         this.version = version;
         this.features = features;
-        this.channel = channel;
         this.outboundHandler = outboundHandler;
         this.action = action;
         this.requestId = requestId;
@@ -77,7 +82,7 @@ public final class TcpTransportChannel implements TransportChannel {
 
     @Override
     public String getProfileName() {
-        return channel.getProfile();
+        return getChannel().getProfile();
     }
 
     @Override
@@ -87,7 +92,7 @@ public void sendResponse(TransportResponse response) throws IOException {
                 // update outbound network time with current time before sending response over network
                 ((QuerySearchResult) response).getShardSearchRequest().setOutboundNetworkTime(System.currentTimeMillis());
             }
-            outboundHandler.sendResponse(version, features, channel, requestId, action, response, compressResponse, isHandshake);
+            outboundHandler.sendResponse(version, features, getChannel(), requestId, action, response, compressResponse, isHandshake);
         } finally {
             release(false);
         }
@@ -96,7 +101,7 @@ public void sendResponse(TransportResponse response) throws IOException {
     @Override
     public void sendResponse(Exception exception) throws IOException {
         try {
-            outboundHandler.sendErrorResponse(version, features, channel, requestId, action, exception);
+            outboundHandler.sendErrorResponse(version, features, getChannel(), requestId, action, exception);
         } finally {
             release(true);
         }
@@ -125,7 +130,4 @@ public Version getVersion() {
         return version;
     }
 
-    public TcpChannel getChannel() {
-        return channel;
-    }
 }
diff --git a/server/src/main/java/org/opensearch/transport/Transport.java b/server/src/main/java/org/opensearch/transport/Transport.java
index 0946d9c8ec626..f516f64d7ee26 100644
--- a/server/src/main/java/org/opensearch/transport/Transport.java
+++ b/server/src/main/java/org/opensearch/transport/Transport.java
@@ -33,15 +33,16 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.collect.MapBuilder;
-import org.opensearch.common.component.LifecycleComponent;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.common.lifecycle.LifecycleComponent;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.ConcurrentMapLong;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -53,6 +54,11 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Predicate;
 
+/**
+ * OpenSearch Transport Interface
+ *
+ * @opensearch.internal
+ */
 public interface Transport extends LifecycleComponent {
 
     /**
@@ -263,6 +269,11 @@ public TransportResponseHandler<? extends TransportResponse> onResponseReceived(
         }
     }
 
+    /**
+     * Request handler implementations
+     *
+     * @opensearch.internal
+     */
     final class RequestHandlers {
 
         private volatile Map<String, RequestHandlerRegistry<? extends TransportRequest>> requestHandlers = Collections.emptyMap();
diff --git a/server/src/main/java/org/opensearch/transport/TransportActionProxy.java b/server/src/main/java/org/opensearch/transport/TransportActionProxy.java
index 1776ab24d465c..a61aec8a34e20 100644
--- a/server/src/main/java/org/opensearch/transport/TransportActionProxy.java
+++ b/server/src/main/java/org/opensearch/transport/TransportActionProxy.java
@@ -32,9 +32,10 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -46,11 +47,18 @@
  * TransportActionProxy allows an arbitrary action to be executed on a defined target node while the initial request is sent to a second
  * node that acts as a request proxy to the target node. This is useful if a node is not directly connected to a target node but is
  * connected to an intermediate node that establishes a transitive connection.
+ *
+ * @opensearch.internal
  */
 public final class TransportActionProxy {
 
     private TransportActionProxy() {} // no instance
 
+    /**
+     * Handler for proxy requests
+     *
+     * @opensearch.internal
+     */
     private static class ProxyRequestHandler<T extends ProxyRequest> implements TransportRequestHandler<T> {
 
         private final TransportService service;
@@ -80,6 +88,11 @@ public void messageReceived(T request, TransportChannel channel, Task task) thro
         }
     }
 
+    /**
+     * Handler for the proxy response
+     *
+     * @opensearch.internal
+     */
     private static class ProxyResponseHandler<T extends TransportResponse> implements TransportResponseHandler<T> {
 
         private final Writeable.Reader<T> reader;
@@ -119,6 +132,11 @@ public String executor() {
         }
     }
 
+    /**
+     * The proxy request
+     *
+     * @opensearch.internal
+     */
     static class ProxyRequest<T extends TransportRequest> extends TransportRequest {
         final T wrapped;
         final DiscoveryNode targetNode;
diff --git a/server/src/main/java/org/opensearch/transport/TransportChannel.java b/server/src/main/java/org/opensearch/transport/TransportChannel.java
index 92d1d07865e52..3c582127f28e8 100644
--- a/server/src/main/java/org/opensearch/transport/TransportChannel.java
+++ b/server/src/main/java/org/opensearch/transport/TransportChannel.java
@@ -36,11 +36,14 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
 /**
  * A transport channel allows to send a response to a request on the channel.
+ *
+ * @opensearch.internal
  */
 public interface TransportChannel {
 
diff --git a/server/src/main/java/org/opensearch/transport/TransportConnectionListener.java b/server/src/main/java/org/opensearch/transport/TransportConnectionListener.java
index 43bfd3f6d0be0..7acb1e9ae09e9 100644
--- a/server/src/main/java/org/opensearch/transport/TransportConnectionListener.java
+++ b/server/src/main/java/org/opensearch/transport/TransportConnectionListener.java
@@ -38,6 +38,8 @@
  * A listener interface that allows to react on transport events. All methods may be
  * executed on network threads. Consumers must fork in the case of long running or blocking
  * operations.
+ *
+ * @opensearch.internal
  */
 public interface TransportConnectionListener {
 
diff --git a/server/src/main/java/org/opensearch/transport/TransportDecompressor.java b/server/src/main/java/org/opensearch/transport/TransportDecompressor.java
index 262438ed75463..8fbc3b7ce6803 100644
--- a/server/src/main/java/org/opensearch/transport/TransportDecompressor.java
+++ b/server/src/main/java/org/opensearch/transport/TransportDecompressor.java
@@ -34,12 +34,13 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.recycler.Recycler;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.compress.CompressorRegistry;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -47,6 +48,11 @@
 import java.util.zip.DataFormatException;
 import java.util.zip.Inflater;
 
+/**
+ * Decompresses data over the transport wire
+ *
+ * @opensearch.internal
+ */
 public class TransportDecompressor implements Closeable {
 
     private final Inflater inflater;
@@ -64,7 +70,8 @@ public TransportDecompressor(PageCacheRecycler recycler) {
     public int decompress(BytesReference bytesReference) throws IOException {
         int bytesConsumed = 0;
         if (hasReadHeader == false) {
-            if (CompressorFactory.COMPRESSOR.isCompressed(bytesReference) == false) {
+            final Compressor compressor = CompressorRegistry.defaultCompressor();
+            if (compressor.isCompressed(bytesReference) == false) {
                 int maxToRead = Math.min(bytesReference.length(), 10);
                 StringBuilder sb = new StringBuilder("stream marked as compressed, but no compressor found, first [").append(maxToRead)
                     .append("] content bytes out of [")
@@ -80,7 +87,7 @@ public int decompress(BytesReference bytesReference) throws IOException {
                 throw new IllegalStateException(sb.toString());
             }
             hasReadHeader = true;
-            int headerLength = CompressorFactory.COMPRESSOR.headerLength();
+            int headerLength = compressor.headerLength();
             bytesReference = bytesReference.slice(headerLength, bytesReference.length() - headerLength);
             bytesConsumed += headerLength;
         }
@@ -130,7 +137,7 @@ public int decompress(BytesReference bytesReference) throws IOException {
     }
 
     public boolean canDecompress(int bytesAvailable) {
-        return hasReadHeader || bytesAvailable >= CompressorFactory.COMPRESSOR.headerLength();
+        return hasReadHeader || bytesAvailable >= CompressorRegistry.defaultCompressor().headerLength();
     }
 
     public boolean isEOS() {
diff --git a/server/src/main/java/org/opensearch/transport/TransportException.java b/server/src/main/java/org/opensearch/transport/TransportException.java
index 00efe52e06ed2..1522f2378bca3 100644
--- a/server/src/main/java/org/opensearch/transport/TransportException.java
+++ b/server/src/main/java/org/opensearch/transport/TransportException.java
@@ -33,10 +33,15 @@
 package org.opensearch.transport;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown for any transport errors
+ *
+ * @opensearch.internal
+ */
 public class TransportException extends OpenSearchException {
     public TransportException(Throwable cause) {
         super(cause);
diff --git a/server/src/main/java/org/opensearch/transport/TransportFuture.java b/server/src/main/java/org/opensearch/transport/TransportFuture.java
index 09759c498fc89..d2abf8c20d34e 100644
--- a/server/src/main/java/org/opensearch/transport/TransportFuture.java
+++ b/server/src/main/java/org/opensearch/transport/TransportFuture.java
@@ -35,6 +35,11 @@
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Future for transport operations
+ *
+ * @opensearch.internal
+ */
 public interface TransportFuture<V> extends Future<V> {
 
     /**
diff --git a/server/src/main/java/org/opensearch/transport/TransportHandshaker.java b/server/src/main/java/org/opensearch/transport/TransportHandshaker.java
index c85a8eebd8fbd..d0f15e08cbbc5 100644
--- a/server/src/main/java/org/opensearch/transport/TransportHandshaker.java
+++ b/server/src/main/java/org/opensearch/transport/TransportHandshaker.java
@@ -33,14 +33,15 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.EOFException;
@@ -52,6 +53,8 @@
 /**
  * Sends and receives transport-level connection handshakes. This class will send the initial handshake,
  * manage state/timeouts while the handshake is in transit, and handle the eventual response.
+ *
+ * @opensearch.internal
  */
 final class TransportHandshaker {
 
@@ -232,7 +235,7 @@ static final class HandshakeRequest extends TransportRequest {
                 version = null;
             } else {
                 try (StreamInput messageStreamInput = remainingMessage.streamInput()) {
-                    this.version = Version.readVersion(messageStreamInput);
+                    this.version = messageStreamInput.readVersion();
                 }
             }
         }
@@ -242,7 +245,7 @@ public void writeTo(StreamOutput streamOutput) throws IOException {
             super.writeTo(streamOutput);
             assert version != null;
             try (BytesStreamOutput messageStreamOutput = new BytesStreamOutput(4)) {
-                Version.writeVersion(version, messageStreamOutput);
+                messageStreamOutput.writeVersion(version);
                 BytesReference reference = messageStreamOutput.bytes();
                 streamOutput.writeBytesReference(reference);
             }
@@ -259,13 +262,13 @@ static final class HandshakeResponse extends TransportResponse {
 
         private HandshakeResponse(StreamInput in) throws IOException {
             super(in);
-            responseVersion = Version.readVersion(in);
+            responseVersion = in.readVersion();
         }
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             assert responseVersion != null;
-            Version.writeVersion(responseVersion, out);
+            out.writeVersion(responseVersion);
         }
 
         Version getResponseVersion() {
diff --git a/server/src/main/java/org/opensearch/transport/TransportInfo.java b/server/src/main/java/org/opensearch/transport/TransportInfo.java
index a65b95661bbf1..75179f7932238 100644
--- a/server/src/main/java/org/opensearch/transport/TransportInfo.java
+++ b/server/src/main/java/org/opensearch/transport/TransportInfo.java
@@ -33,14 +33,14 @@
 package org.opensearch.transport;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.node.ReportingService;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -48,6 +48,11 @@
 
 import static org.opensearch.common.Booleans.parseBoolean;
 
+/**
+ * Transport information
+ *
+ * @opensearch.internal
+ */
 public class TransportInfo implements ReportingService.Info {
 
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(TransportInfo.class);
diff --git a/server/src/main/java/org/opensearch/transport/TransportInterceptor.java b/server/src/main/java/org/opensearch/transport/TransportInterceptor.java
index ae76bd4899127..9ee2db6d39893 100644
--- a/server/src/main/java/org/opensearch/transport/TransportInterceptor.java
+++ b/server/src/main/java/org/opensearch/transport/TransportInterceptor.java
@@ -33,10 +33,13 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.transport.TransportResponse;
 
 /**
  * This interface allows plugins to intercept requests on both the sender and the receiver side.
+ *
+ * @opensearch.internal
  */
 public interface TransportInterceptor {
     /**
diff --git a/server/src/main/java/org/opensearch/transport/TransportKeepAlive.java b/server/src/main/java/org/opensearch/transport/TransportKeepAlive.java
index 1874b0f803b78..bbf4a9b668d5e 100644
--- a/server/src/main/java/org/opensearch/transport/TransportKeepAlive.java
+++ b/server/src/main/java/org/opensearch/transport/TransportKeepAlive.java
@@ -34,15 +34,15 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.AsyncBiFunction;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.component.Lifecycle;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractLifecycleRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -56,6 +56,8 @@
  * Implements the scheduling and sending of keep alive pings. Client channels send keep alive pings to the
  * server and server channels respond. Pings are only sent at the scheduled time if the channel did not send
  * and receive a message since the last ping.
+ *
+ * @opensearch.internal
  */
 final class TransportKeepAlive implements Closeable {
 
diff --git a/server/src/main/java/org/opensearch/transport/TransportLogger.java b/server/src/main/java/org/opensearch/transport/TransportLogger.java
index 6de285473c73a..1876164c52e58 100644
--- a/server/src/main/java/org/opensearch/transport/TransportLogger.java
+++ b/server/src/main/java/org/opensearch/transport/TransportLogger.java
@@ -34,15 +34,20 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.compress.CompressorRegistry;
 
 import java.io.IOException;
 
+/**
+ * Logs transport activity
+ *
+ * @opensearch.internal
+ */
 public final class TransportLogger {
 
     private static final Logger logger = LogManager.getLogger(TransportLogger.class);
@@ -180,7 +185,7 @@ private static String format(TcpChannel channel, InboundMessage message, String
     private static StreamInput decompressingStream(byte status, StreamInput streamInput) throws IOException {
         if (TransportStatus.isCompress(status) && streamInput.available() > 0) {
             try {
-                return new InputStreamStreamInput(CompressorFactory.COMPRESSOR.threadLocalInputStream(streamInput));
+                return new InputStreamStreamInput(CompressorRegistry.defaultCompressor().threadLocalInputStream(streamInput));
             } catch (IllegalArgumentException e) {
                 throw new IllegalStateException("stream marked as compressed, but is missing deflate header");
             }
diff --git a/server/src/main/java/org/opensearch/transport/TransportMessageListener.java b/server/src/main/java/org/opensearch/transport/TransportMessageListener.java
index fd5ca057ba9bb..dfcd7acce3706 100644
--- a/server/src/main/java/org/opensearch/transport/TransportMessageListener.java
+++ b/server/src/main/java/org/opensearch/transport/TransportMessageListener.java
@@ -32,7 +32,13 @@
 package org.opensearch.transport;
 
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.transport.TransportResponse;
 
+/**
+ * Listens for transport messages
+ *
+ * @opensearch.internal
+ */
 public interface TransportMessageListener {
 
     TransportMessageListener NOOP_LISTENER = new TransportMessageListener() {
diff --git a/server/src/main/java/org/opensearch/transport/TransportRequest.java b/server/src/main/java/org/opensearch/transport/TransportRequest.java
index 4dd18102e4c06..f13b460dfb0c3 100644
--- a/server/src/main/java/org/opensearch/transport/TransportRequest.java
+++ b/server/src/main/java/org/opensearch/transport/TransportRequest.java
@@ -32,14 +32,25 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportMessage;
 import org.opensearch.tasks.TaskAwareRequest;
-import org.opensearch.tasks.TaskId;
 
 import java.io.IOException;
 
+/**
+ * A transport request
+ *
+ * @opensearch.internal
+ */
 public abstract class TransportRequest extends TransportMessage implements TaskAwareRequest {
+    /**
+     * Empty transport request
+     *
+     * @opensearch.internal
+     */
     public static class Empty extends TransportRequest {
         public static final Empty INSTANCE = new Empty();
 
diff --git a/server/src/main/java/org/opensearch/transport/TransportRequestDeduplicator.java b/server/src/main/java/org/opensearch/transport/TransportRequestDeduplicator.java
index 4d33f071328c1..9746c5f5cb94e 100644
--- a/server/src/main/java/org/opensearch/transport/TransportRequestDeduplicator.java
+++ b/server/src/main/java/org/opensearch/transport/TransportRequestDeduplicator.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -44,6 +44,8 @@
  * Deduplicator for {@link TransportRequest}s that keeps track of {@link TransportRequest}s that should
  * not be sent in parallel.
  * @param <T> Transport Request Class
+ *
+ * @opensearch.internal
  */
 public final class TransportRequestDeduplicator<T extends TransportRequest> {
 
@@ -68,7 +70,7 @@ public void executeOnce(T request, ActionListener<Void> listener, BiConsumer<T,
 
     /**
      * Remove all tracked requests from this instance so that the first time {@link #executeOnce} is invoked with any request it triggers
-     * an actual request execution. Use this e.g. for requests to master that need to be sent again on master failover.
+     * an actual request execution. Use this e.g. for requests to cluster-manager that need to be sent again on cluster-manager failover.
      */
     public void clear() {
         requests.clear();
diff --git a/server/src/main/java/org/opensearch/transport/TransportRequestHandler.java b/server/src/main/java/org/opensearch/transport/TransportRequestHandler.java
index 5e6cb1e6c4007..54ee1b68fc9aa 100644
--- a/server/src/main/java/org/opensearch/transport/TransportRequestHandler.java
+++ b/server/src/main/java/org/opensearch/transport/TransportRequestHandler.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.tasks.Task;
 
+/**
+ * Handles transport requests
+ *
+ * @opensearch.internal
+ */
 public interface TransportRequestHandler<T extends TransportRequest> {
 
     void messageReceived(T request, TransportChannel channel, Task task) throws Exception;
diff --git a/server/src/main/java/org/opensearch/transport/TransportRequestOptions.java b/server/src/main/java/org/opensearch/transport/TransportRequestOptions.java
index 8b8638da6c524..fe54d8185ea5f 100644
--- a/server/src/main/java/org/opensearch/transport/TransportRequestOptions.java
+++ b/server/src/main/java/org/opensearch/transport/TransportRequestOptions.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Options for transport requests
+ *
+ * @opensearch.internal
+ */
 public class TransportRequestOptions {
 
     private final TimeValue timeout;
@@ -54,6 +59,11 @@ public Type type() {
 
     public static final TransportRequestOptions EMPTY = new TransportRequestOptions.Builder().build();
 
+    /**
+     * Type of transport request
+     *
+     * @opensearch.internal
+     */
     public enum Type {
         RECOVERY,
         BULK,
@@ -66,6 +76,11 @@ public static Builder builder() {
         return new Builder();
     }
 
+    /**
+     * Builder for transport request options
+     *
+     * @opensearch.internal
+     */
     public static class Builder {
         private TimeValue timeout;
         private Type type = Type.REG;
diff --git a/server/src/main/java/org/opensearch/transport/TransportResponseHandler.java b/server/src/main/java/org/opensearch/transport/TransportResponseHandler.java
index 8d6129b98390b..8992af18edb48 100644
--- a/server/src/main/java/org/opensearch/transport/TransportResponseHandler.java
+++ b/server/src/main/java/org/opensearch/transport/TransportResponseHandler.java
@@ -32,12 +32,18 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.function.Function;
 
+/**
+ * Handles transport responses
+ *
+ * @opensearch.internal
+ */
 public interface TransportResponseHandler<T extends TransportResponse> extends Writeable.Reader<T> {
 
     void handleResponse(T response);
@@ -46,6 +52,13 @@ public interface TransportResponseHandler<T extends TransportResponse> extends W
 
     String executor();
 
+    /**
+     * This method should be handling the rejection/failure scenarios where connection to the node is rejected or failed.
+     * It should be used to clear up the resources held by the {@link TransportResponseHandler}.
+     * @param exp exception
+     */
+    default void handleRejection(Exception exp) {}
+
     default <Q extends TransportResponse> TransportResponseHandler<Q> wrap(Function<Q, T> converter, Writeable.Reader<Q> reader) {
         final TransportResponseHandler<T> self = this;
         return new TransportResponseHandler<Q>() {
diff --git a/server/src/main/java/org/opensearch/transport/TransportSerializationException.java b/server/src/main/java/org/opensearch/transport/TransportSerializationException.java
index 964d24adc11f4..1a5f9cec28ea1 100644
--- a/server/src/main/java/org/opensearch/transport/TransportSerializationException.java
+++ b/server/src/main/java/org/opensearch/transport/TransportSerializationException.java
@@ -32,10 +32,15 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 
 import java.io.IOException;
 
+/**
+ * Thrown if there is an error serializing data for transport
+ *
+ * @opensearch.internal
+ */
 public class TransportSerializationException extends TransportException {
 
     public TransportSerializationException(StreamInput in) throws IOException {
diff --git a/server/src/main/java/org/opensearch/transport/TransportService.java b/server/src/main/java/org/opensearch/transport/TransportService.java
index ad46ed742c806..b7684d472f30a 100644
--- a/server/src/main/java/org/opensearch/transport/TransportService.java
+++ b/server/src/main/java/org/opensearch/transport/TransportService.java
@@ -36,35 +36,43 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.LegacyESVersion;
+import org.opensearch.OpenSearchServerException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.io.stream.Streamables;
 import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.service.ReportingService;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.node.NodeClosedException;
-import org.opensearch.node.ReportingService;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanBuilder;
+import org.opensearch.telemetry.tracing.SpanScope;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.handler.TraceableTransportResponseHandler;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -87,6 +95,11 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+/**
+ * The main OpenSearch transport service
+ *
+ * @opensearch.internal
+ */
 public class TransportService extends AbstractLifecycleComponent
     implements
         ReportingService<TransportInfo>,
@@ -127,11 +140,11 @@ protected boolean removeEldestEntry(Map.Entry eldest) {
     // tracer log
 
     private final Logger tracerLog;
-
     volatile String[] tracerLogInclude;
     volatile String[] tracerLogExclude;
 
     private final RemoteClusterService remoteClusterService;
+    private final Tracer tracer;
 
     /** if set will call requests sent to this id to shortcut and executed locally */
     volatile DiscoveryNode localNode = null;
@@ -159,11 +172,24 @@ public boolean isClosed() {
         public void close() {}
     };
 
+    static {
+        /**
+         * Registers server specific types as a streamables for serialization
+         * over the {@link StreamOutput} and {@link StreamInput} wire
+         */
+        Streamables.registerStreamables();
+        /** Registers OpenSearch server specific exceptions (exceptions outside of core library) */
+        OpenSearchServerException.registerExceptions();
+    }
+
+    /** does nothing. easy way to ensure class is loaded so the above static block is called to register the streamables */
+    public static void ensureClassloaded() {}
+
     /**
      * Build the service.
      *
      * @param clusterSettings if non null, the {@linkplain TransportService} will register with the {@link ClusterSettings} for settings
-    *   *    updates for {@link TransportSettings#TRACE_LOG_EXCLUDE_SETTING} and {@link TransportSettings#TRACE_LOG_INCLUDE_SETTING}.
+     *   *    updates for {@link TransportSettings#TRACE_LOG_EXCLUDE_SETTING} and {@link TransportSettings#TRACE_LOG_INCLUDE_SETTING}.
      */
     public TransportService(
         Settings settings,
@@ -172,7 +198,8 @@ public TransportService(
         TransportInterceptor transportInterceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
         this(
             settings,
@@ -182,7 +209,8 @@ public TransportService(
             localNodeFactory,
             clusterSettings,
             taskHeaders,
-            new ClusterConnectionManager(settings, transport)
+            new ClusterConnectionManager(settings, transport),
+            tracer
         );
     }
 
@@ -194,7 +222,8 @@ public TransportService(
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
         Set<String> taskHeaders,
-        ConnectionManager connectionManager
+        ConnectionManager connectionManager,
+        Tracer tracer
     ) {
         this.transport = transport;
         transport.setSlowLogThreshold(TransportSettings.SLOW_OPERATION_THRESHOLD_SETTING.get(settings));
@@ -205,10 +234,11 @@ public TransportService(
         setTracerLogInclude(TransportSettings.TRACE_LOG_INCLUDE_SETTING.get(settings));
         setTracerLogExclude(TransportSettings.TRACE_LOG_EXCLUDE_SETTING.get(settings));
         tracerLog = Loggers.getLogger(logger, ".tracer");
-        taskManager = createTaskManager(settings, threadPool, taskHeaders);
+        taskManager = createTaskManager(settings, clusterSettings, threadPool, taskHeaders);
         this.interceptor = transportInterceptor;
         this.asyncSender = interceptor.interceptSender(this::sendRequestInternal);
         this.remoteClusterClient = DiscoveryNode.isRemoteClusterClient(settings);
+        this.tracer = tracer;
         remoteClusterService = new RemoteClusterService(settings, this);
         responseHandlers = transport.getResponseHandlers();
         if (clusterSettings != null) {
@@ -241,8 +271,17 @@ public TaskManager getTaskManager() {
         return taskManager;
     }
 
-    protected TaskManager createTaskManager(Settings settings, ThreadPool threadPool, Set<String> taskHeaders) {
-        return new TaskManager(settings, threadPool, taskHeaders);
+    protected TaskManager createTaskManager(
+        Settings settings,
+        ClusterSettings clusterSettings,
+        ThreadPool threadPool,
+        Set<String> taskHeaders
+    ) {
+        if (clusterSettings != null) {
+            return TaskManager.createTaskManagerWithClusterSettings(settings, clusterSettings, threadPool, taskHeaders);
+        } else {
+            return new TaskManager(settings, threadPool, taskHeaders);
+        }
     }
 
     /**
@@ -277,7 +316,12 @@ protected void doStart() {
 
         if (remoteClusterClient) {
             // here we start to connect to the remote clusters
-            remoteClusterService.initializeRemoteClusters();
+            remoteClusterService.initializeRemoteClusters(
+                ActionListener.wrap(
+                    r -> logger.info("Remote clusters initialized successfully."),
+                    e -> logger.error("Remote clusters initialization failed partially", e)
+                )
+            );
         }
     }
 
@@ -296,6 +340,7 @@ protected void doStop() {
                 getExecutorService().execute(new AbstractRunnable() {
                     @Override
                     public void onRejection(Exception e) {
+                        holderToNotify.handler().handleRejection(e);
                         // if we get rejected during node shutdown we don't wanna bubble it up
                         logger.debug(
                             () -> new ParameterizedMessage(
@@ -308,6 +353,7 @@ public void onRejection(Exception e) {
 
                     @Override
                     public void onFailure(Exception e) {
+                        holderToNotify.handler().handleRejection(e);
                         logger.warn(
                             () -> new ParameterizedMessage(
                                 "failed to notify response handler on exception, action: {}",
@@ -386,6 +432,20 @@ public void connectToNode(DiscoveryNode node) throws ConnectTransportException {
         connectToNode(node, (ConnectionProfile) null);
     }
 
+    /**
+     * Connect to the specified node as an extension with the default connection profile
+     *
+     * @param node the node to connect to
+     */
+    public void connectToNodeAsExtension(DiscoveryNode node, String extensionUniqueId) throws ConnectTransportException {
+        connectToNodeAsExtension(node, (ConnectionProfile) null, extensionUniqueId);
+    }
+
+    // We are skipping node validation for extensibility as extensionNode and opensearchNode(LocalNode) will have different ephemeral id's
+    public void connectToExtensionNode(final DiscoveryNode node) {
+        PlainActionFuture.get(fut -> connectToExtensionNode(node, (ConnectionProfile) null, ActionListener.map(fut, x -> null)));
+    }
+
     /**
      * Connect to the specified node with the given connection profile
      *
@@ -396,6 +456,23 @@ public void connectToNode(final DiscoveryNode node, ConnectionProfile connection
         PlainActionFuture.get(fut -> connectToNode(node, connectionProfile, ActionListener.map(fut, x -> null)));
     }
 
+    /**
+     * Connect to the specified node with the given connection profile
+     *
+     * @param node the node to connect to
+     * @param connectionProfile the connection profile to use when connecting to this node
+     * @param extensionUniqueIq the id of the extension
+     */
+    public void connectToNodeAsExtension(final DiscoveryNode node, ConnectionProfile connectionProfile, String extensionUniqueIq) {
+        PlainActionFuture.get(
+            fut -> connectToNodeAsExtension(node, connectionProfile, extensionUniqueIq, ActionListener.map(fut, x -> null))
+        );
+    }
+
+    public void connectToExtensionNode(final DiscoveryNode node, ConnectionProfile connectionProfile) {
+        PlainActionFuture.get(fut -> connectToExtensionNode(node, connectionProfile, ActionListener.map(fut, x -> null)));
+    }
+
     /**
      * Connect to the specified node with the given connection profile.
      * The ActionListener will be called on the calling thread or the generic thread pool.
@@ -407,6 +484,10 @@ public void connectToNode(DiscoveryNode node, ActionListener<Void> listener) thr
         connectToNode(node, null, listener);
     }
 
+    public void connectToExtensionNode(DiscoveryNode node, ActionListener<Void> listener) throws ConnectTransportException {
+        connectToExtensionNode(node, null, listener);
+    }
+
     /**
      * Connect to the specified node with the given connection profile.
      * The ActionListener will be called on the calling thread or the generic thread pool.
@@ -423,14 +504,84 @@ public void connectToNode(final DiscoveryNode node, ConnectionProfile connection
         connectionManager.connectToNode(node, connectionProfile, connectionValidator(node), listener);
     }
 
+    /**
+     * Connect to the specified node as an extension with the given connection profile.
+     * The ActionListener will be called on the calling thread or the generic thread pool.
+     *
+     * @param node the node to connect to
+     * @param connectionProfile the connection profile to use when connecting to this node
+     * @param extensionUniqueId the id of the extension
+     * @param listener the action listener to notify
+     */
+    public void connectToNodeAsExtension(
+        final DiscoveryNode node,
+        ConnectionProfile connectionProfile,
+        String extensionUniqueId,
+        ActionListener<Void> listener
+    ) {
+        if (isLocalNode(node)) {
+            listener.onResponse(null);
+            return;
+        }
+        connectionManager.connectToNode(
+            node,
+            connectionProfile,
+            connectionValidatorForExtensionConnectingToNode(node, extensionUniqueId),
+            listener
+        );
+    }
+
+    public void connectToExtensionNode(final DiscoveryNode node, ConnectionProfile connectionProfile, ActionListener<Void> listener) {
+        if (isLocalNode(node)) {
+            listener.onResponse(null);
+            return;
+        }
+        connectionManager.connectToNode(node, connectionProfile, extensionConnectionValidator(node), listener);
+    }
+
     public ConnectionManager.ConnectionValidator connectionValidator(DiscoveryNode node) {
         return (newConnection, actualProfile, listener) -> {
             // We don't validate cluster names to allow for CCS connections.
             handshake(newConnection, actualProfile.getHandshakeTimeout().millis(), cn -> true, ActionListener.map(listener, resp -> {
                 final DiscoveryNode remote = resp.discoveryNode;
+
+                if (node.equals(remote) == false) {
+                    throw new ConnectTransportException(node, "handshake failed. unexpected remote node " + remote);
+                }
+
+                return null;
+            }));
+        };
+    }
+
+    public ConnectionManager.ConnectionValidator connectionValidatorForExtensionConnectingToNode(
+        DiscoveryNode node,
+        String extensionUniqueId
+    ) {
+        return (newConnection, actualProfile, listener) -> {
+            // We don't validate cluster names to allow for CCS connections.
+            String currentId = threadPool.getThreadContext().getHeader("extension_unique_id");
+            if (Strings.isNullOrEmpty(currentId) || !extensionUniqueId.equals(currentId)) {
+                threadPool.getThreadContext().putHeader("extension_unique_id", extensionUniqueId);
+            }
+            handshake(newConnection, actualProfile.getHandshakeTimeout().millis(), cn -> true, ActionListener.map(listener, resp -> {
+                final DiscoveryNode remote = resp.discoveryNode;
+
                 if (node.equals(remote) == false) {
                     throw new ConnectTransportException(node, "handshake failed. unexpected remote node " + remote);
                 }
+
+                return null;
+            }));
+        };
+    }
+
+    public ConnectionManager.ConnectionValidator extensionConnectionValidator(DiscoveryNode node) {
+        return (newConnection, actualProfile, listener) -> {
+            // We don't validate cluster names to allow for CCS connections.
+            handshake(newConnection, actualProfile.getHandshakeTimeout().millis(), cn -> true, ActionListener.map(listener, resp -> {
+                final DiscoveryNode remote = resp.discoveryNode;
+                logger.info("Connection validation was skipped");
                 return null;
             }));
         };
@@ -561,6 +712,11 @@ public ConnectionManager getConnectionManager() {
         return connectionManager;
     }
 
+    /**
+     * Internal Handshake request
+     *
+     * @opensearch.internal
+     */
     static class HandshakeRequest extends TransportRequest {
 
         public static final HandshakeRequest INSTANCE = new HandshakeRequest();
@@ -573,6 +729,11 @@ private HandshakeRequest() {}
 
     }
 
+    /**
+     * Internal handshake response
+     *
+     * @opensearch.internal
+     */
     public static class HandshakeResponse extends TransportResponse {
         private final DiscoveryNode discoveryNode;
         private final ClusterName clusterName;
@@ -588,7 +749,7 @@ public HandshakeResponse(StreamInput in) throws IOException {
             super(in);
             discoveryNode = in.readOptionalWriteable(DiscoveryNode::new);
             clusterName = new ClusterName(in);
-            Version tmpVersion = Version.readVersion(in);
+            Version tmpVersion = in.readVersion();
             if (in.getVersion().onOrBefore(LegacyESVersion.V_7_10_2)) {
                 tmpVersion = LegacyESVersion.V_7_10_2;
             }
@@ -600,9 +761,9 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeOptionalWriteable(discoveryNode);
             clusterName.writeTo(out);
             if (out.getVersion().before(Version.V_1_0_0)) {
-                Version.writeVersion(LegacyESVersion.V_7_10_2, out);
+                out.writeVersion(LegacyESVersion.V_7_10_2);
             } else {
-                Version.writeVersion(version, out);
+                out.writeVersion(version);
             }
         }
 
@@ -717,52 +878,60 @@ public final <T extends TransportResponse> void sendRequest(
         final TransportRequestOptions options,
         final TransportResponseHandler<T> handler
     ) {
-        try {
-            final TransportResponseHandler<T> delegate;
-            if (request.getParentTask().isSet()) {
-                // TODO: capture the connection instead so that we can cancel child tasks on the remote connections.
-                final Releasable unregisterChildNode = taskManager.registerChildNode(request.getParentTask().getId(), connection.getNode());
-                delegate = new TransportResponseHandler<T>() {
-                    @Override
-                    public void handleResponse(T response) {
-                        unregisterChildNode.close();
-                        handler.handleResponse(response);
-                    }
+        final Span span = tracer.startSpan(SpanBuilder.from(action, connection));
+        try (SpanScope spanScope = tracer.withSpanInScope(span)) {
+            TransportResponseHandler<T> traceableTransportResponseHandler = TraceableTransportResponseHandler.create(handler, span, tracer);
+            try {
+                logger.debug("Action: " + action);
+                final TransportResponseHandler<T> delegate;
+                if (request.getParentTask().isSet()) {
+                    // TODO: capture the connection instead so that we can cancel child tasks on the remote connections.
+                    final Releasable unregisterChildNode = taskManager.registerChildNode(
+                        request.getParentTask().getId(),
+                        connection.getNode()
+                    );
+                    delegate = new TransportResponseHandler<T>() {
+                        @Override
+                        public void handleResponse(T response) {
+                            unregisterChildNode.close();
+                            traceableTransportResponseHandler.handleResponse(response);
+                        }
 
-                    @Override
-                    public void handleException(TransportException exp) {
-                        unregisterChildNode.close();
-                        handler.handleException(exp);
-                    }
+                        @Override
+                        public void handleException(TransportException exp) {
+                            unregisterChildNode.close();
+                            traceableTransportResponseHandler.handleException(exp);
+                        }
 
-                    @Override
-                    public String executor() {
-                        return handler.executor();
-                    }
+                        @Override
+                        public String executor() {
+                            return traceableTransportResponseHandler.executor();
+                        }
 
-                    @Override
-                    public T read(StreamInput in) throws IOException {
-                        return handler.read(in);
-                    }
+                        @Override
+                        public T read(StreamInput in) throws IOException {
+                            return traceableTransportResponseHandler.read(in);
+                        }
 
-                    @Override
-                    public String toString() {
-                        return getClass().getName() + "/[" + action + "]:" + handler.toString();
-                    }
-                };
-            } else {
-                delegate = handler;
-            }
-            asyncSender.sendRequest(connection, action, request, options, delegate);
-        } catch (final Exception ex) {
-            // the caller might not handle this so we invoke the handler
-            final TransportException te;
-            if (ex instanceof TransportException) {
-                te = (TransportException) ex;
-            } else {
-                te = new TransportException("failure to send", ex);
+                        @Override
+                        public String toString() {
+                            return getClass().getName() + "/[" + action + "]:" + handler.toString();
+                        }
+                    };
+                } else {
+                    delegate = traceableTransportResponseHandler;
+                }
+                asyncSender.sendRequest(connection, action, request, options, delegate);
+            } catch (final Exception ex) {
+                // the caller might not handle this so we invoke the handler
+                final TransportException te;
+                if (ex instanceof TransportException) {
+                    te = (TransportException) ex;
+                } else {
+                    te = new TransportException("failure to send", ex);
+                }
+                traceableTransportResponseHandler.handleException(te);
             }
-            handler.handleException(te);
         }
     }
 
@@ -884,6 +1053,7 @@ private <T extends TransportResponse> void sendRequestInternal(
                 threadPool.executor(executor).execute(new AbstractRunnable() {
                     @Override
                     public void onRejection(Exception e) {
+                        contextToNotify.handler().handleRejection(e);
                         // if we get rejected during node shutdown we don't wanna bubble it up
                         logger.debug(
                             () -> new ParameterizedMessage(
@@ -896,6 +1066,7 @@ public void onRejection(Exception e) {
 
                     @Override
                     public void onFailure(Exception e) {
+                        contextToNotify.handler().handleRejection(e);
                         logger.warn(
                             () -> new ParameterizedMessage(
                                 "failed to notify response handler on exception, action: {}",
@@ -1280,6 +1451,11 @@ private void scheduleTimeout(TimeValue timeout) {
         }
     }
 
+    /**
+     * Holder for timeout information
+     *
+     * @opensearch.internal
+     */
     static class TimeoutInfoHolder {
 
         private final DiscoveryNode node;
@@ -1367,6 +1543,11 @@ void setTimeoutHandler(TimeoutHandler handler) {
 
     }
 
+    /**
+     * A channel for a direct response
+     *
+     * @opensearch.internal
+     */
     static class DirectResponseChannel implements TransportChannel {
         final DiscoveryNode localNode;
         private final String action;
diff --git a/server/src/main/java/org/opensearch/transport/TransportSettings.java b/server/src/main/java/org/opensearch/transport/TransportSettings.java
index cacdbce60c365..23305c58ef834 100644
--- a/server/src/main/java/org/opensearch/transport/TransportSettings.java
+++ b/server/src/main/java/org/opensearch/transport/TransportSettings.java
@@ -35,8 +35,8 @@
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 import java.util.Arrays;
 import java.util.List;
@@ -49,6 +49,11 @@
 import static org.opensearch.common.settings.Setting.listSetting;
 import static org.opensearch.common.settings.Setting.timeSetting;
 
+/**
+ * Settings for transport config
+ *
+ * @opensearch.internal
+ */
 public final class TransportSettings {
 
     public static final String DEFAULT_PROFILE = "default";
diff --git a/server/src/main/java/org/opensearch/transport/TransportStats.java b/server/src/main/java/org/opensearch/transport/TransportStats.java
index e83de2f599b37..c9f1bebade6b3 100644
--- a/server/src/main/java/org/opensearch/transport/TransportStats.java
+++ b/server/src/main/java/org/opensearch/transport/TransportStats.java
@@ -33,15 +33,20 @@
 package org.opensearch.transport;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
+/**
+ * Stats for transport activity
+ *
+ * @opensearch.internal
+ */
 public class TransportStats implements Writeable, ToXContentFragment {
 
     private final long serverOpen;
diff --git a/server/src/main/java/org/opensearch/transport/TransportStatus.java b/server/src/main/java/org/opensearch/transport/TransportStatus.java
index 2622b1d67b458..dab572949e688 100644
--- a/server/src/main/java/org/opensearch/transport/TransportStatus.java
+++ b/server/src/main/java/org/opensearch/transport/TransportStatus.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.transport;
 
+/**
+ * Status for transport activity
+ *
+ * @opensearch.internal
+ */
 public final class TransportStatus {
 
     private static final byte STATUS_REQRES = 1 << 0;
diff --git a/server/src/main/java/org/opensearch/transport/Transports.java b/server/src/main/java/org/opensearch/transport/Transports.java
index 7d9f013db5338..e6e9b7e5edb7e 100644
--- a/server/src/main/java/org/opensearch/transport/Transports.java
+++ b/server/src/main/java/org/opensearch/transport/Transports.java
@@ -38,6 +38,11 @@
 
 import java.util.Arrays;
 
+/**
+ * Utility class for transport
+ *
+ * @opensearch.internal
+ */
 public enum Transports {
     ;
 
diff --git a/server/src/main/java/org/opensearch/transport/package-info.java b/server/src/main/java/org/opensearch/transport/package-info.java
new file mode 100644
index 0000000000000..d7005c3e221aa
--- /dev/null
+++ b/server/src/main/java/org/opensearch/transport/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** All Transport Classes needed for wire communication in OpenSearch */
+package org.opensearch.transport;
diff --git a/server/src/main/java/org/opensearch/usage/UsageService.java b/server/src/main/java/org/opensearch/usage/UsageService.java
index 6f8f0076d50f8..14e25b591bda0 100644
--- a/server/src/main/java/org/opensearch/usage/UsageService.java
+++ b/server/src/main/java/org/opensearch/usage/UsageService.java
@@ -61,6 +61,8 @@
 
 /**
  * A service to monitor usage of OpenSearch features.
+ *
+ * @opensearch.internal
  */
 public class UsageService {
 
diff --git a/server/src/main/java/org/opensearch/usage/package-info.java b/server/src/main/java/org/opensearch/usage/package-info.java
new file mode 100644
index 0000000000000..708bd8af33b39
--- /dev/null
+++ b/server/src/main/java/org/opensearch/usage/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base Usage Service package for tracking OpenSearch telemetry. */
+package org.opensearch.usage;
diff --git a/server/src/main/java/org/opensearch/watcher/AbstractResourceWatcher.java b/server/src/main/java/org/opensearch/watcher/AbstractResourceWatcher.java
index 9f33bb2d4f868..dc0976b123327 100644
--- a/server/src/main/java/org/opensearch/watcher/AbstractResourceWatcher.java
+++ b/server/src/main/java/org/opensearch/watcher/AbstractResourceWatcher.java
@@ -38,6 +38,8 @@
 /**
  * Abstract resource watcher framework, which handles adding and removing listeners
  * and calling resource observer.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractResourceWatcher<Listener> implements ResourceWatcher {
     private final List<Listener> listeners = new CopyOnWriteArrayList<>();
diff --git a/server/src/main/java/org/opensearch/watcher/FileChangesListener.java b/server/src/main/java/org/opensearch/watcher/FileChangesListener.java
index a9843ad6ed879..7c6132946bbcb 100644
--- a/server/src/main/java/org/opensearch/watcher/FileChangesListener.java
+++ b/server/src/main/java/org/opensearch/watcher/FileChangesListener.java
@@ -35,6 +35,8 @@
 
 /**
  * Callback interface that file changes File Watcher is using to notify listeners about changes.
+ *
+ * @opensearch.internal
  */
 public interface FileChangesListener {
     /**
diff --git a/server/src/main/java/org/opensearch/watcher/FileWatcher.java b/server/src/main/java/org/opensearch/watcher/FileWatcher.java
index ec9fe0c1a1615..82f95d6a1622c 100644
--- a/server/src/main/java/org/opensearch/watcher/FileWatcher.java
+++ b/server/src/main/java/org/opensearch/watcher/FileWatcher.java
@@ -33,8 +33,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.util.FileSystemUtils;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -46,6 +46,8 @@
  * File resources watcher
  *
  * The file watcher checks directory and all its subdirectories for file changes and notifies its listeners accordingly
+ *
+ * @opensearch.internal
  */
 public class FileWatcher extends AbstractResourceWatcher<FileChangesListener> {
 
diff --git a/server/src/main/java/org/opensearch/watcher/ResourceWatcher.java b/server/src/main/java/org/opensearch/watcher/ResourceWatcher.java
index 43bcf601c997f..0c656c52388df 100644
--- a/server/src/main/java/org/opensearch/watcher/ResourceWatcher.java
+++ b/server/src/main/java/org/opensearch/watcher/ResourceWatcher.java
@@ -38,6 +38,8 @@
  * <p>
  * Different resource watchers can be registered with {@link ResourceWatcherService} to be called
  * periodically in order to check for changes in different external resources.
+ *
+ * @opensearch.internal
  */
 public interface ResourceWatcher {
     /**
diff --git a/server/src/main/java/org/opensearch/watcher/ResourceWatcherService.java b/server/src/main/java/org/opensearch/watcher/ResourceWatcherService.java
index 9422ef7aa60ae..9b9c00cd4252f 100644
--- a/server/src/main/java/org/opensearch/watcher/ResourceWatcherService.java
+++ b/server/src/main/java/org/opensearch/watcher/ResourceWatcherService.java
@@ -33,12 +33,13 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.Scheduler.Cancellable;
+import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
 
 import java.io.Closeable;
@@ -53,10 +54,18 @@
  * method. This service will call {@link org.opensearch.watcher.ResourceWatcher#checkAndNotify()} method of all
  * registered watcher periodically. The frequency of checks can be specified using {@code resource.reload.interval} setting, which
  * defaults to {@code 60s}. The service can be disabled by setting {@code resource.reload.enabled} setting to {@code false}.
+ *
+ * @opensearch.api
  */
+@PublicApi(since = "1.0.0")
 public class ResourceWatcherService implements Closeable {
     private static final Logger logger = LogManager.getLogger(ResourceWatcherService.class);
 
+    /**
+     * Frequency level to watch.
+     *
+     * @opensearch.internal
+     */
     public enum Frequency {
 
         /**
diff --git a/server/src/main/java/org/opensearch/watcher/WatcherHandle.java b/server/src/main/java/org/opensearch/watcher/WatcherHandle.java
index b6aa1df39e4eb..6890364cd0cd6 100644
--- a/server/src/main/java/org/opensearch/watcher/WatcherHandle.java
+++ b/server/src/main/java/org/opensearch/watcher/WatcherHandle.java
@@ -32,6 +32,11 @@
 
 package org.opensearch.watcher;
 
+/**
+ * Handle to a watcher
+ *
+ * @opensearch.internal
+ */
 public class WatcherHandle<W extends ResourceWatcher> {
 
     private final ResourceWatcherService.ResourceMonitor monitor;
diff --git a/server/src/main/java/org/opensearch/watcher/package-info.java b/server/src/main/java/org/opensearch/watcher/package-info.java
new file mode 100644
index 0000000000000..e10cd0fcb90dd
--- /dev/null
+++ b/server/src/main/java/org/opensearch/watcher/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base File / Directory Watcher package. */
+package org.opensearch.watcher;
diff --git a/server/src/main/java11/org/opensearch/monitor/jvm/JvmPid.java b/server/src/main/java11/org/opensearch/monitor/jvm/JvmPid.java
deleted file mode 100644
index 9a2fbfbd27c68..0000000000000
--- a/server/src/main/java11/org/opensearch/monitor/jvm/JvmPid.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.monitor.jvm;
-
-class JvmPid {
-
-    static long getPid() {
-        return ProcessHandle.current().pid();
-    }
-
-}
diff --git a/server/src/main/proto/extensions/ExtensionIdentityProto.proto b/server/src/main/proto/extensions/ExtensionIdentityProto.proto
new file mode 100644
index 0000000000000..16941c23b6794
--- /dev/null
+++ b/server/src/main/proto/extensions/ExtensionIdentityProto.proto
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+option java_outer_classname = "ExtensionIdentityProto";
+
+message ExtensionIdentity {
+  string uniqueId = 1;
+}
diff --git a/server/src/main/proto/extensions/ExtensionRequestProto.proto b/server/src/main/proto/extensions/ExtensionRequestProto.proto
new file mode 100644
index 0000000000000..9526e4145b281
--- /dev/null
+++ b/server/src/main/proto/extensions/ExtensionRequestProto.proto
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+import "extensions/ExtensionIdentityProto.proto";
+option java_outer_classname = "ExtensionRequestProto";
+
+enum RequestType {
+    REQUEST_EXTENSION_CLUSTER_STATE = 0;
+    REQUEST_EXTENSION_CLUSTER_SETTINGS = 1;
+    REQUEST_EXTENSION_REGISTER_REST_ACTIONS = 2;
+    REQUEST_EXTENSION_REGISTER_SETTINGS = 3;
+    REQUEST_EXTENSION_ENVIRONMENT_SETTINGS = 4;
+    REQUEST_EXTENSION_DEPENDENCY_INFORMATION = 5;
+    CREATE_COMPONENT = 6;
+    ON_INDEX_MODULE = 7;
+    GET_SETTINGS = 8;
+}
+
+message ExtensionRequest {
+  ExtensionIdentity identity = 1;
+  RequestType requestType = 2;
+}
diff --git a/server/src/main/proto/extensions/HandleTransportRequestProto.proto b/server/src/main/proto/extensions/HandleTransportRequestProto.proto
new file mode 100644
index 0000000000000..79ba80a6c2021
--- /dev/null
+++ b/server/src/main/proto/extensions/HandleTransportRequestProto.proto
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+option java_outer_classname = "ExtensionTransportMessageProto";
+
+message ExtensionTransportMessage {
+  string action = 1;
+  bytes requestBytes = 2;
+}
diff --git a/server/src/main/proto/extensions/RegisterRestActionsProto.proto b/server/src/main/proto/extensions/RegisterRestActionsProto.proto
new file mode 100644
index 0000000000000..fa5599b118a8b
--- /dev/null
+++ b/server/src/main/proto/extensions/RegisterRestActionsProto.proto
@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+import "extensions/ExtensionIdentityProto.proto";
+option java_outer_classname = "RegisterRestActionsProto";
+
+message RegisterRestActions {
+  ExtensionIdentity identity = 1;
+  repeated string restActions = 2;
+  repeated string deprecatedRestActions = 3;
+}
diff --git a/server/src/main/proto/extensions/RegisterTransportActionsProto.proto b/server/src/main/proto/extensions/RegisterTransportActionsProto.proto
new file mode 100644
index 0000000000000..a6ce252cedf88
--- /dev/null
+++ b/server/src/main/proto/extensions/RegisterTransportActionsProto.proto
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+import "extensions/ExtensionIdentityProto.proto";
+option java_outer_classname = "RegisterTransportActionsProto";
+
+message RegisterTransportActions {
+  ExtensionIdentity identity = 1;
+  repeated string transportActions = 2;
+}
diff --git a/server/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider b/server/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
new file mode 100644
index 0000000000000..8d93d45035f3f
--- /dev/null
+++ b/server/src/main/resources/META-INF/services/org.opensearch.core.compress.spi.CompressorProvider
@@ -0,0 +1,9 @@
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# The OpenSearch Contributors require contributions made to
+# this file be licensed under the Apache-2.0 license or a
+# compatible open source license.
+#
+
+org.opensearch.common.compress.spi.ServerCompressorProvider
diff --git a/server/src/main/resources/META-INF/services/org.opensearch.common.xcontent.ErrorOnUnknown b/server/src/main/resources/META-INF/services/org.opensearch.core.xcontent.ErrorOnUnknown
similarity index 100%
rename from server/src/main/resources/META-INF/services/org.opensearch.common.xcontent.ErrorOnUnknown
rename to server/src/main/resources/META-INF/services/org.opensearch.core.xcontent.ErrorOnUnknown
diff --git a/server/src/main/resources/META-INF/services/org.opensearch.common.xcontent.XContentBuilderExtension b/server/src/main/resources/META-INF/services/org.opensearch.core.xcontent.XContentBuilderExtension
similarity index 100%
rename from server/src/main/resources/META-INF/services/org.opensearch.common.xcontent.XContentBuilderExtension
rename to server/src/main/resources/META-INF/services/org.opensearch.core.xcontent.XContentBuilderExtension
diff --git a/server/src/main/resources/org/opensearch/bootstrap/jvm/deny-jvm-versions.txt b/server/src/main/resources/org/opensearch/bootstrap/jvm/deny-jvm-versions.txt
new file mode 100644
index 0000000000000..e3bfbea397570
--- /dev/null
+++ b/server/src/main/resources/org/opensearch/bootstrap/jvm/deny-jvm-versions.txt
@@ -0,0 +1,10 @@
+// Some version and version range examples are:
+// 11.0.2: <... reason ...>             version 11.0.2.
+// [11.0.2, 11.0.14): <... reason ...>  versions 11.0.2.2 (included) to 11.0.14 (not included)
+// [11.0.2, 11.0.14]: <... reason ...>  versions 11.0.2 to 11.0.14 (both included)
+// [11.0.2,): <... reason ...>          versions 11.0.2 and higher
+// [11.0.2,*): <... reason ...>          versions 11.0.2 and higher
+// (, 11.0.14]: <... reason ...>  versions up to 11.0.14 (included)
+// (*, 11.0.14]: <... reason ...>  versions up to 11.0.14 (included)
+
+[11.0.2, 11.0.14): for more details, please check https://github.com/opensearch-project/OpenSearch/issues/2791 and https://bugs.openjdk.java.net/browse/JDK-8259541
\ No newline at end of file
diff --git a/server/src/main/resources/org/opensearch/bootstrap/security.policy b/server/src/main/resources/org/opensearch/bootstrap/security.policy
index 97b73aedf24bb..77cd0ab05278e 100644
--- a/server/src/main/resources/org/opensearch/bootstrap/security.policy
+++ b/server/src/main/resources/org/opensearch/bootstrap/security.policy
@@ -79,6 +79,12 @@ grant codeBase "${codebase.jna}" {
   permission java.lang.RuntimePermission "accessDeclaredMembers";
 };
 
+
+// ZSTD compression
+grant codeBase "${codebase.zstd-jni}" {
+  permission java.lang.RuntimePermission "loadLibrary.*";
+};
+
 //// Everything else:
 
 grant {
@@ -116,10 +122,13 @@ grant {
   permission java.util.PropertyPermission "solr.data.dir", "write";
   permission java.util.PropertyPermission "solr.directoryFactory", "write";
 
-  // set by ESTestCase to improve test reproducibility
+  // set by OpenSearchTestCase to improve test reproducibility
   // TODO: set this with gradle or some other way that repros with seed?
   permission java.util.PropertyPermission "processors.override", "write";
 
+  // needed for feature flags
+  permission java.util.PropertyPermission "opensearch.experimental.feature.*", "write";
+
   // TODO: these simply trigger a noisy warning if its unable to clear the properties
   // fix that in randomizedtesting
   permission java.util.PropertyPermission "junit4.childvm.count", "write";
diff --git a/server/src/main/resources/org/opensearch/bootstrap/test-framework.policy b/server/src/main/resources/org/opensearch/bootstrap/test-framework.policy
index bcf0b704374c9..52205ee498eb3 100644
--- a/server/src/main/resources/org/opensearch/bootstrap/test-framework.policy
+++ b/server/src/main/resources/org/opensearch/bootstrap/test-framework.policy
@@ -123,6 +123,11 @@ grant codeBase "${codebase.junit-rt.jar}" {
   permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
 };
 
+grant codeBase "${codebase.idea_rt.jar}" {
+  // allows IntelliJ IDEA (2022.3.3) JUnit test runner to control number of test iterations
+  permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
+};
+
 grant codeBase "file:${gradle.dist.lib}/-" {
   // gradle test worker code needs a slew of permissions, we give full access here since gradle isn't a production
   // dependency and there's no point in exercising the security policy against it
@@ -138,4 +143,8 @@ grant codeBase "file:${gradle.worker.jar}" {
 grant {
   // since the gradle test worker jar is on the test classpath, our tests should be able to read it
   permission java.io.FilePermission "${gradle.worker.jar}", "read";
+  permission java.lang.RuntimePermission "accessDeclaredMembers";
+  permission java.lang.RuntimePermission "reflectionFactoryAccess";
+  permission java.lang.RuntimePermission "accessClassInPackage.sun.reflect";
+  permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
 };
diff --git a/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json b/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
index 54e9d39902f03..58b6b2d3bc873 100644
--- a/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
+++ b/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
@@ -1,7 +1,7 @@
 {
   "_doc" : {
     "_meta": {
-      "version": 3
+      "version": 4
     },
     "dynamic" : "strict",
     "properties" : {
diff --git a/server/src/test/java/org/opensearch/BuildTests.java b/server/src/test/java/org/opensearch/BuildTests.java
index eeb6890699fdc..f264ccb1a5c2d 100644
--- a/server/src/test/java/org/opensearch/BuildTests.java
+++ b/server/src/test/java/org/opensearch/BuildTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch;
 
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -60,9 +60,11 @@ public void testJarMetadata() throws IOException {
         URL url = Build.getOpenSearchCodeSourceLocation();
         // throws exception if does not exist, or we cannot access it
         try (InputStream ignored = FileSystemUtils.openFileURLStream(url)) {}
-        // these should never be null
+        // these should never be null or "unknown"
         assertNotNull(Build.CURRENT.date());
+        assertNotEquals(Build.CURRENT.date(), "unknown");
         assertNotNull(Build.CURRENT.hash());
+        assertNotEquals(Build.CURRENT.hash(), "unknown");
     }
 
     public void testIsProduction() {
@@ -187,7 +189,7 @@ private static class WriteableBuild implements Writeable {
         private final Build build;
 
         WriteableBuild(StreamInput in) throws IOException {
-            build = Build.readBuild(in);
+            build = in.readBuild();
         }
 
         WriteableBuild(Build build) {
@@ -196,7 +198,7 @@ private static class WriteableBuild implements Writeable {
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            Build.writeBuild(build, out);
+            out.writeBuild(build);
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/ExceptionSerializationTests.java b/server/src/test/java/org/opensearch/ExceptionSerializationTests.java
index b5859e1fb18a9..9ec2bbc4d027f 100644
--- a/server/src/test/java/org/opensearch/ExceptionSerializationTests.java
+++ b/server/src/test/java/org/opensearch/ExceptionSerializationTests.java
@@ -44,33 +44,49 @@
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.action.support.replication.ReplicationOperation;
 import org.opensearch.client.AbstractClientHeadersTestCase;
+import org.opensearch.cluster.NotMasterException;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.IndexCreateBlockException;
 import org.opensearch.cluster.coordination.CoordinationStateRejectedException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
+import org.opensearch.cluster.coordination.NodeHealthCheckFailureException;
+import org.opensearch.cluster.decommission.DecommissioningFailedException;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.IllegalShardRoutingStateException;
+import org.opensearch.cluster.routing.NodeWeighedAwayException;
+import org.opensearch.cluster.routing.PreferenceBasedSearchNotAllowedException;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
+import org.opensearch.cluster.routing.UnsupportedWeightedRoutingStateException;
+import org.opensearch.cluster.service.ClusterManagerThrottlingException;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NotSerializableExceptionWrapper;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.CancellableThreadsTests;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentLocation;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.io.stream.NotSerializableExceptionWrapper;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotException;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.crypto.CryptoRegistryException;
+import org.opensearch.discovery.MasterNotDiscoveredException;
 import org.opensearch.env.ShardLockObtainFailedException;
-import org.opensearch.index.Index;
 import org.opensearch.index.engine.RecoveryEngineException;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.index.seqno.RetentionLeaseAlreadyExistsException;
@@ -78,16 +94,15 @@
 import org.opensearch.index.seqno.RetentionLeaseNotFoundException;
 import org.opensearch.index.shard.IllegalIndexShardStateException;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.PrimaryShardClosedException;
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.indices.IndexTemplateMissingException;
 import org.opensearch.indices.InvalidIndexTemplateException;
 import org.opensearch.indices.recovery.PeerRecoveryNotFound;
 import org.opensearch.indices.recovery.RecoverFilesRecoveryException;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
 import org.opensearch.ingest.IngestProcessorException;
-import org.opensearch.cluster.coordination.NodeHealthCheckFailureException;
 import org.opensearch.repositories.RepositoryException;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.admin.indices.AliasesNotFoundException;
 import org.opensearch.search.SearchContextMissingException;
 import org.opensearch.search.SearchException;
@@ -95,10 +110,12 @@
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.aggregations.MultiBucketConsumerService;
 import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.search.pipeline.SearchPipelineProcessingException;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotException;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInProgressException;
+import org.opensearch.snapshots.SnapshotInUseDeletionException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.transport.ActionNotFoundTransportException;
@@ -147,7 +164,8 @@ public void testExceptionRegistration() throws ClassNotFoundException, IOExcepti
         final Set<Class<?>> hasDedicatedWrite = new HashSet<>();
         final Set<Class<?>> registered = new HashSet<>();
         final String path = "/org/opensearch";
-        final Path startPath = PathUtils.get(OpenSearchException.class.getProtectionDomain().getCodeSource().getLocation().toURI())
+        final Path coreLibStartPath = PathUtils.get(OpenSearchException.class.getProtectionDomain().getCodeSource().getLocation().toURI());
+        final Path startPath = PathUtils.get(OpenSearchServerException.class.getProtectionDomain().getCodeSource().getLocation().toURI())
             .resolve("org")
             .resolve("opensearch");
         final Set<String> ignore = Sets.newHashSet(
@@ -229,12 +247,22 @@ public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOEx
             }
         };
 
+        // walk the core library start path
+        Files.walkFileTree(coreLibStartPath, visitor);
+        // walk the server module start path
         Files.walkFileTree(startPath, visitor);
         final Path testStartPath = PathUtils.get(ExceptionSerializationTests.class.getResource(path).toURI());
         Files.walkFileTree(testStartPath, visitor);
         assertTrue(notRegistered.remove(TestException.class));
         assertTrue(notRegistered.remove(UnknownHeaderException.class));
-        assertTrue("Classes subclassing OpenSearchException must be registered \n" + notRegistered.toString(), notRegistered.isEmpty());
+        // Remove the deprecated exception classes from the unregistered list.
+        assertTrue(notRegistered.remove(NotMasterException.class));
+        assertTrue(notRegistered.remove(MasterNotDiscoveredException.class));
+        assertTrue(
+            "Classes subclassing OpenSearchException must be registered in OpenSearchException.OpenSearchExceptionHandle \n"
+                + notRegistered,
+            notRegistered.isEmpty()
+        );
         assertTrue(registered.removeAll(OpenSearchException.getRegisteredKeys())); // check
         assertEquals(registered.toString(), 0, registered.size());
     }
@@ -510,17 +538,25 @@ public void testFailedNodeException() throws IOException {
     }
 
     public void testClusterBlockException() throws IOException {
-        ClusterBlockException ex = serialize(new ClusterBlockException(singleton(NoMasterBlockService.NO_MASTER_BLOCK_WRITES)));
-        assertEquals("blocked by: [SERVICE_UNAVAILABLE/2/no master];", ex.getMessage());
-        assertTrue(ex.blocks().contains(NoMasterBlockService.NO_MASTER_BLOCK_WRITES));
+        ClusterBlockException ex = serialize(
+            new ClusterBlockException(singleton(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES))
+        );
+        assertEquals("blocked by: [SERVICE_UNAVAILABLE/2/no cluster-manager];", ex.getMessage());
+        assertTrue(ex.blocks().contains(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES));
         assertEquals(1, ex.blocks().size());
     }
 
     public void testNotSerializableExceptionWrapper() throws IOException {
         NotSerializableExceptionWrapper ex = serialize(new NotSerializableExceptionWrapper(new NullPointerException()));
-        assertEquals("{\"type\":\"null_pointer_exception\",\"reason\":\"null_pointer_exception: null\"}", Strings.toString(ex));
+        assertEquals(
+            "{\"type\":\"null_pointer_exception\",\"reason\":\"null_pointer_exception: null\"}",
+            Strings.toString(MediaTypeRegistry.JSON, ex)
+        );
         ex = serialize(new NotSerializableExceptionWrapper(new IllegalArgumentException("nono!")));
-        assertEquals("{\"type\":\"illegal_argument_exception\",\"reason\":\"illegal_argument_exception: nono!\"}", Strings.toString(ex));
+        assertEquals(
+            "{\"type\":\"illegal_argument_exception\",\"reason\":\"illegal_argument_exception: nono!\"}",
+            Strings.toString(MediaTypeRegistry.JSON, ex)
+        );
 
         class UnknownException extends Exception {
             UnknownException(final String message) {
@@ -691,10 +727,10 @@ public void testThatIdsAreUnique() {
 
     public void testIds() {
         Map<Integer, Class<? extends OpenSearchException>> ids = new HashMap<>();
-        ids.put(0, org.opensearch.index.snapshots.IndexShardSnapshotFailedException.class);
+        ids.put(0, IndexShardSnapshotFailedException.class);
         ids.put(1, org.opensearch.search.dfs.DfsPhaseExecutionException.class);
         ids.put(2, org.opensearch.common.util.CancellableThreads.ExecutionCancelledException.class);
-        ids.put(3, org.opensearch.discovery.MasterNotDiscoveredException.class);
+        ids.put(3, org.opensearch.discovery.ClusterManagerNotDiscoveredException.class);
         ids.put(4, org.opensearch.OpenSearchSecurityException.class);
         ids.put(5, org.opensearch.index.snapshots.IndexShardRestoreException.class);
         ids.put(6, org.opensearch.indices.IndexClosedException.class);
@@ -731,7 +767,7 @@ public void testIds() {
         ids.put(37, org.opensearch.index.mapper.MapperException.class);
         ids.put(38, org.opensearch.indices.InvalidTypeNameException.class);
         ids.put(39, org.opensearch.snapshots.SnapshotRestoreException.class);
-        ids.put(40, org.opensearch.common.ParsingException.class);
+        ids.put(40, ParsingException.class);
         ids.put(41, org.opensearch.index.shard.IndexShardClosedException.class);
         ids.put(42, org.opensearch.indices.recovery.RecoverFilesRecoveryException.class);
         ids.put(43, org.opensearch.index.translog.TruncatedTranslogException.class);
@@ -753,7 +789,7 @@ public void testIds() {
         ids.put(59, null); // was OpenSearchRejectedExecutionException, which is no longer an instance of OpenSearchException
         ids.put(60, null); // EarlyTerminationException was removed in 6.0
         ids.put(61, null); // RoutingValidationException was removed in 5.0
-        ids.put(62, org.opensearch.common.io.stream.NotSerializableExceptionWrapper.class);
+        ids.put(62, NotSerializableExceptionWrapper.class);
         ids.put(63, org.opensearch.indices.AliasFilterParsingException.class);
         ids.put(64, null); // DeleteByQueryFailedEngineException was removed in 3.0
         ids.put(65, org.opensearch.gateway.GatewayException.class);
@@ -786,7 +822,7 @@ public void testIds() {
         ids.put(95, null);
         ids.put(96, org.opensearch.snapshots.InvalidSnapshotNameException.class);
         ids.put(97, org.opensearch.index.shard.IllegalIndexShardStateException.class);
-        ids.put(98, org.opensearch.index.snapshots.IndexShardSnapshotException.class);
+        ids.put(98, IndexShardSnapshotException.class);
         ids.put(99, org.opensearch.index.shard.IndexShardNotStartedException.class);
         ids.put(100, org.opensearch.action.search.SearchPhaseExecutionException.class);
         ids.put(101, org.opensearch.transport.ActionNotFoundTransportException.class);
@@ -821,7 +857,7 @@ public void testIds() {
         ids.put(130, org.opensearch.action.NoShardAvailableActionException.class);
         ids.put(131, org.opensearch.action.UnavailableShardsException.class);
         ids.put(132, org.opensearch.index.engine.FlushFailedEngineException.class);
-        ids.put(133, org.opensearch.common.breaker.CircuitBreakingException.class);
+        ids.put(133, org.opensearch.core.common.breaker.CircuitBreakingException.class);
         ids.put(134, org.opensearch.transport.NodeNotConnectedException.class);
         ids.put(135, org.opensearch.index.mapper.StrictDynamicMappingException.class);
         ids.put(136, org.opensearch.action.support.replication.TransportReplicationAction.RetryOnReplicaException.class);
@@ -832,9 +868,9 @@ public void testIds() {
         ids.put(141, org.opensearch.index.query.QueryShardException.class);
         ids.put(142, ShardStateAction.NoLongerPrimaryShardException.class);
         ids.put(143, org.opensearch.script.ScriptException.class);
-        ids.put(144, org.opensearch.cluster.NotMasterException.class);
+        ids.put(144, org.opensearch.cluster.NotClusterManagerException.class);
         ids.put(145, org.opensearch.OpenSearchStatusException.class);
-        ids.put(146, org.opensearch.tasks.TaskCancelledException.class);
+        ids.put(146, org.opensearch.core.tasks.TaskCancelledException.class);
         ids.put(147, org.opensearch.env.ShardLockObtainFailedException.class);
         ids.put(148, null);
         ids.put(149, MultiBucketConsumerService.TooManyBucketsException.class);
@@ -849,6 +885,18 @@ public void testIds() {
         ids.put(158, PeerRecoveryNotFound.class);
         ids.put(159, NodeHealthCheckFailureException.class);
         ids.put(160, NoSeedNodeLeftException.class);
+        ids.put(161, ReplicationFailedException.class);
+        ids.put(162, PrimaryShardClosedException.class);
+        ids.put(163, DecommissioningFailedException.class);
+        ids.put(164, NodeDecommissionedException.class);
+        ids.put(165, ClusterManagerThrottlingException.class);
+        ids.put(166, SnapshotInUseDeletionException.class);
+        ids.put(167, UnsupportedWeightedRoutingStateException.class);
+        ids.put(168, PreferenceBasedSearchNotAllowedException.class);
+        ids.put(169, NodeWeighedAwayException.class);
+        ids.put(170, SearchPipelineProcessingException.class);
+        ids.put(171, CryptoRegistryException.class);
+        ids.put(10001, IndexCreateBlockException.class);
 
         Map<Class<? extends OpenSearchException>, Integer> reverse = new HashMap<>();
         for (Map.Entry<Integer, Class<? extends OpenSearchException>> entry : ids.entrySet()) {
@@ -859,6 +907,10 @@ public void testIds() {
 
         for (final Tuple<Integer, Class<? extends OpenSearchException>> tuple : OpenSearchException.classes()) {
             assertNotNull(tuple.v1());
+            assertNotNull(
+                tuple.v2().getName() + " not found in ExceptionSerializationTests.testIds. Please add it.",
+                reverse.get(tuple.v2())
+            );
             assertEquals((int) reverse.get(tuple.v2()), (int) tuple.v1());
         }
 
diff --git a/server/src/test/java/org/opensearch/ExceptionsHelperTests.java b/server/src/test/java/org/opensearch/ExceptionsHelperTests.java
index d16b2e9d291b0..e2b22ccbba768 100644
--- a/server/src/test/java/org/opensearch/ExceptionsHelperTests.java
+++ b/server/src/test/java/org/opensearch/ExceptionsHelperTests.java
@@ -33,18 +33,19 @@
 package org.opensearch;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.commons.codec.DecoderException;
 import org.apache.lucene.index.CorruptIndexException;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.QueryShardException;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.RemoteClusterAware;
@@ -113,6 +114,12 @@ public void testStatus() {
         assertThat(ExceptionsHelper.status(new OpenSearchRejectedExecutionException("rejected")), equalTo(RestStatus.TOO_MANY_REQUESTS));
     }
 
+    public void testSummaryMessage() {
+        assertThat(ExceptionsHelper.summaryMessage(new IllegalArgumentException("illegal")), equalTo("Invalid argument"));
+        assertThat(ExceptionsHelper.summaryMessage(new JsonParseException(null, "illegal")), equalTo("Failed to parse JSON"));
+        assertThat(ExceptionsHelper.summaryMessage(new OpenSearchRejectedExecutionException("rejected")), equalTo("Too many requests"));
+    }
+
     public void testGroupBy() {
         ShardOperationFailedException[] failures = new ShardOperationFailedException[] {
             createShardFailureParsingException("error", "node0", "index", 0, null),
diff --git a/server/src/test/java/org/opensearch/LegacyESVersionTests.java b/server/src/test/java/org/opensearch/LegacyESVersionTests.java
index 8fb3636dd8b2c..e4be7e422d49e 100644
--- a/server/src/test/java/org/opensearch/LegacyESVersionTests.java
+++ b/server/src/test/java/org/opensearch/LegacyESVersionTests.java
@@ -19,15 +19,15 @@
 import java.util.Map;
 import java.util.Set;
 
+import static org.opensearch.LegacyESVersion.V_7_0_0;
+import static org.opensearch.VersionTests.isCompatible;
+import static org.opensearch.test.VersionUtils.randomLegacyVersion;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.sameInstance;
-import static org.opensearch.LegacyESVersion.V_7_0_0;
-import static org.opensearch.test.VersionUtils.randomLegacyVersion;
-import static org.opensearch.VersionTests.isCompatible;
 
 /**
  * tests LegacyESVersion utilities.
@@ -63,8 +63,8 @@ public void testVersionComparison() {
 
         // compare opensearch version to LegacyESVersion
         assertThat(Version.V_1_0_0.compareMajor(LegacyESVersion.V_7_0_0), is(0));
-        assertThat(Version.V_1_0_0.compareMajor(LegacyESVersion.fromString("6.3.0")), is(1));
-        assertThat(LegacyESVersion.fromString("6.3.0").compareMajor(Version.V_1_0_0), is(-1));
+        assertThat(Version.V_2_0_0.compareMajor(LegacyESVersion.fromString("7.3.0")), is(1));
+        assertThat(LegacyESVersion.fromString("7.3.0").compareMajor(Version.V_2_0_0), is(-1));
     }
 
     public void testMin() {
@@ -114,7 +114,7 @@ public void testWrongVersionFromString() {
     }
 
     public void testVersionNoPresentInSettings() {
-        Exception e = expectThrows(IllegalStateException.class, () -> LegacyESVersion.indexCreated(Settings.builder().build()));
+        Exception e = expectThrows(IllegalStateException.class, () -> IndexMetadata.indexCreated(Settings.builder().build()));
         assertThat(e.getMessage(), containsString("[index.version.created] is not present"));
     }
 
@@ -123,7 +123,7 @@ public void testIndexCreatedVersion() {
         final LegacyESVersion version = (LegacyESVersion) LegacyESVersion.fromId(6000026);
         assertEquals(
             version,
-            LegacyESVersion.indexCreated(
+            IndexMetadata.indexCreated(
                 Settings.builder().put(IndexMetadata.SETTING_INDEX_UUID, "foo").put(IndexMetadata.SETTING_VERSION_CREATED, version).build()
             )
         );
diff --git a/server/src/test/java/org/opensearch/OpenSearchExceptionTests.java b/server/src/test/java/org/opensearch/OpenSearchExceptionTests.java
index 9f32af143ee2d..592217d9c65d0 100644
--- a/server/src/test/java/org/opensearch/OpenSearchExceptionTests.java
+++ b/server/src/test/java/org/opensearch/OpenSearchExceptionTests.java
@@ -41,31 +41,31 @@
 import org.opensearch.action.support.broadcast.BroadcastShardOperationFailedException;
 import org.opensearch.client.transport.NoNodeAvailableException;
 import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.index.shard.IndexShardRecoveringException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.repositories.RepositoryException;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.ScriptException;
 import org.opensearch.search.SearchContextMissingException;
 import org.opensearch.search.SearchParseException;
@@ -250,7 +250,7 @@ public void testDeduplicate() throws IOException {
             String expected = "{\"type\":\"search_phase_execution_exception\",\"reason\":\"all shards failed\",\"phase\":\"search\","
                 + "\"grouped\":true,\"failed_shards\":[{\"shard\":1,\"index\":\"foo\",\"node\":\"node_1\",\"reason\":"
                 + "{\"type\":\"parsing_exception\",\"reason\":\"foobar\",\"line\":1,\"col\":2}}]}";
-            assertEquals(expected, Strings.toString(builder));
+            assertEquals(expected, builder.toString());
         }
         {
             ShardSearchFailure failure = new ShardSearchFailure(
@@ -279,7 +279,7 @@ public void testDeduplicate() throws IOException {
                 + "\"reason\":{\"type\":\"parsing_exception\",\"reason\":\"foobar\",\"line\":1,\"col\":2}},{\"shard\":1,"
                 + "\"index\":\"foo1\",\"node\":\"node_1\",\"reason\":{\"type\":\"query_shard_exception\",\"reason\":\"foobar\","
                 + "\"index\":\"foo1\",\"index_uuid\":\"_na_\"}}]}";
-            assertEquals(expected, Strings.toString(builder));
+            assertEquals(expected, builder.toString());
         }
         {
             ShardSearchFailure failure = new ShardSearchFailure(
@@ -306,7 +306,7 @@ public void testDeduplicate() throws IOException {
                 + "\"phase\":\"search\",\"grouped\":true,\"failed_shards\":[{\"shard\":1,\"index\":\"foo\",\"node\":\"node_1\","
                 + "\"reason\":{\"type\":\"parsing_exception\",\"reason\":\"foobar\",\"line\":1,\"col\":2}}],"
                 + "\"caused_by\":{\"type\":\"null_pointer_exception\",\"reason\":null}}";
-            assertEquals(expected, Strings.toString(builder));
+            assertEquals(expected, builder.toString());
         }
     }
 
@@ -412,11 +412,11 @@ public void testToXContent() throws IOException {
                 Collections.singletonMap(OpenSearchException.REST_EXCEPTION_SKIP_STACK_TRACE, "false")
             );
             String actual;
-            try (XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent())) {
+            try (XContentBuilder builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent())) {
                 builder.startObject();
                 e.toXContent(builder, params);
                 builder.endObject();
-                actual = Strings.toString(builder);
+                actual = builder.toString();
             }
             assertThat(
                 actual,
@@ -449,8 +449,8 @@ public void testGenerateThrowableToXContent() throws IOException {
 
         { // test equivalence
             OpenSearchException ex = new RemoteTransportException("foobar", new FileNotFoundException("foo not found"));
-            String toXContentString = Strings.toString(ex);
-            String throwableString = Strings.toString((builder, params) -> {
+            String toXContentString = Strings.toString(MediaTypeRegistry.JSON, ex);
+            String throwableString = Strings.toString(MediaTypeRegistry.JSON, (builder, params) -> {
                 OpenSearchException.generateThrowableXContent(builder, params, ex);
                 return builder;
             });
@@ -478,7 +478,10 @@ public void testToXContentWithHeadersAndMetadata() throws IOException {
             "foo",
             new OpenSearchException(
                 "bar",
-                new OpenSearchException("baz", new ClusterBlockException(singleton(NoMasterBlockService.NO_MASTER_BLOCK_WRITES)))
+                new OpenSearchException(
+                    "baz",
+                    new ClusterBlockException(singleton(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES))
+                )
             )
         );
         e.addHeader("foo_0", "0");
@@ -499,7 +502,7 @@ public void testToXContentWithHeadersAndMetadata() throws IOException {
             + "\"reason\":\"baz\","
             + "\"caused_by\":{"
             + "\"type\":\"cluster_block_exception\","
-            + "\"reason\":\"blocked by: [SERVICE_UNAVAILABLE/2/no master];\""
+            + "\"reason\":\"blocked by: [SERVICE_UNAVAILABLE/2/no cluster-manager];\""
             + "}"
             + "}"
             + "},"
@@ -512,7 +515,7 @@ public void testToXContentWithHeadersAndMetadata() throws IOException {
         assertExceptionAsJson(e, expectedJson);
 
         OpenSearchException parsed;
-        try (XContentParser parser = createParser(XContentType.JSON.xContent(), expectedJson)) {
+        try (XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), expectedJson)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             parsed = OpenSearchException.fromXContent(parser);
             assertEquals(XContentParser.Token.END_OBJECT, parser.currentToken());
@@ -537,7 +540,7 @@ public void testToXContentWithHeadersAndMetadata() throws IOException {
         cause = (OpenSearchException) cause.getCause();
         assertEquals(
             cause.getMessage(),
-            "OpenSearch exception [type=cluster_block_exception, reason=blocked by: [SERVICE_UNAVAILABLE/2/no master];]"
+            "OpenSearch exception [type=cluster_block_exception, reason=blocked by: [SERVICE_UNAVAILABLE/2/no cluster-manager];]"
         );
     }
 
@@ -739,7 +742,7 @@ public void testThrowableToAndFromXContent() throws IOException {
         BytesReference throwableBytes = toShuffledXContent((builder, params) -> {
             OpenSearchException.generateThrowableXContent(builder, params, throwable);
             return builder;
-        }, xContent.type(), ToXContent.EMPTY_PARAMS, randomBoolean());
+        }, xContent.mediaType(), ToXContent.EMPTY_PARAMS, randomBoolean());
 
         OpenSearchException parsedException;
         try (XContentParser parser = createParser(xContent, throwableBytes)) {
@@ -771,7 +774,7 @@ public void testUnknownFailureToAndFromXContent() throws IOException {
             // Prints a null failure using generateFailureXContent()
             OpenSearchException.generateFailureXContent(builder, params, null, randomBoolean());
             return builder;
-        }, xContent.type(), ToXContent.EMPTY_PARAMS, randomBoolean());
+        }, xContent.mediaType(), ToXContent.EMPTY_PARAMS, randomBoolean());
 
         OpenSearchException parsedFailure;
         try (XContentParser parser = createParser(xContent, failureBytes)) {
@@ -795,7 +798,7 @@ public void testFailureToAndFromXContentWithNoDetails() throws IOException {
         BytesReference failureBytes = toShuffledXContent((builder, params) -> {
             OpenSearchException.generateFailureXContent(builder, params, failure, false);
             return builder;
-        }, xContent.type(), ToXContent.EMPTY_PARAMS, randomBoolean());
+        }, xContent.mediaType(), ToXContent.EMPTY_PARAMS, randomBoolean());
 
         try (XContentParser parser = createParser(xContent, failureBytes)) {
             failureBytes = BytesReference.bytes(shuffleXContent(parser, randomBoolean()));
@@ -811,12 +814,7 @@ public void testFailureToAndFromXContentWithNoDetails() throws IOException {
         }
         assertNotNull(parsedFailure);
 
-        String reason;
-        if (failure instanceof OpenSearchException) {
-            reason = failure.getClass().getSimpleName() + "[" + failure.getMessage() + "]";
-        } else {
-            reason = "No OpenSearchException found";
-        }
+        String reason = ExceptionsHelper.summaryMessage(failure);
         assertEquals(OpenSearchException.buildMessage("exception", reason, null), parsedFailure.getMessage());
         assertEquals(0, parsedFailure.getHeaders().size());
         assertEquals(0, parsedFailure.getMetadata().size());
@@ -954,7 +952,7 @@ public void testFailureToAndFromXContentWithDetails() throws IOException {
         BytesReference failureBytes = toShuffledXContent((builder, params) -> {
             OpenSearchException.generateFailureXContent(builder, params, finalFailure, true);
             return builder;
-        }, xContent.type(), ToXContent.EMPTY_PARAMS, randomBoolean());
+        }, xContent.mediaType(), ToXContent.EMPTY_PARAMS, randomBoolean());
 
         try (XContentParser parser = createParser(xContent, failureBytes)) {
             failureBytes = BytesReference.bytes(shuffleXContent(parser, randomBoolean()));
@@ -979,8 +977,8 @@ public void testFailureToAndFromXContentWithDetails() throws IOException {
      * be rendered like the REST API does when the "error_trace" parameter is set to true.
      */
     private static void assertToXContentAsJson(ToXContent e, String expectedJson) throws IOException {
-        BytesReference actual = XContentHelper.toXContent(e, XContentType.JSON, randomBoolean());
-        assertToXContentEquivalent(new BytesArray(expectedJson), actual, XContentType.JSON);
+        BytesReference actual = org.opensearch.core.xcontent.XContentHelper.toXContent(e, MediaTypeRegistry.JSON, randomBoolean());
+        assertToXContentEquivalent(new BytesArray(expectedJson), actual, MediaTypeRegistry.JSON);
     }
 
     private static void assertExceptionAsJson(Exception e, String expectedJson) throws IOException {
@@ -1032,9 +1030,10 @@ public static Tuple<Throwable, OpenSearchException> randomExceptions() {
         int type = randomIntBetween(0, 5);
         switch (type) {
             case 0:
-                actual = new ClusterBlockException(singleton(NoMasterBlockService.NO_MASTER_BLOCK_WRITES));
+                actual = new ClusterBlockException(singleton(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES));
                 expected = new OpenSearchException(
-                    "OpenSearch exception [type=cluster_block_exception, " + "reason=blocked by: [SERVICE_UNAVAILABLE/2/no master];]"
+                    "OpenSearch exception [type=cluster_block_exception, "
+                        + "reason=blocked by: [SERVICE_UNAVAILABLE/2/no cluster-manager];]"
                 );
                 break;
             case 1: // Simple opensearch exception with headers (other metadata of type number are not parsed)
diff --git a/server/src/test/java/org/opensearch/VersionTests.java b/server/src/test/java/org/opensearch/VersionTests.java
index beff71eceab0d..c20ebf7a83f3a 100644
--- a/server/src/test/java/org/opensearch/VersionTests.java
+++ b/server/src/test/java/org/opensearch/VersionTests.java
@@ -49,8 +49,8 @@
 import java.util.Map;
 import java.util.Set;
 
-import static org.opensearch.Version.V_1_3_0;
 import static org.opensearch.Version.MASK;
+import static org.opensearch.Version.V_1_3_0;
 import static org.opensearch.test.VersionUtils.allVersions;
 import static org.opensearch.test.VersionUtils.randomOpenSearchVersion;
 import static org.opensearch.test.VersionUtils.randomVersion;
@@ -175,7 +175,7 @@ public void testWrongVersionFromString() {
     }
 
     public void testVersionNoPresentInSettings() {
-        Exception e = expectThrows(IllegalStateException.class, () -> Version.indexCreated(Settings.builder().build()));
+        Exception e = expectThrows(IllegalStateException.class, () -> IndexMetadata.indexCreated(Settings.builder().build()));
         assertThat(e.getMessage(), containsString("[index.version.created] is not present"));
     }
 
@@ -184,7 +184,7 @@ public void testIndexCreatedVersion() {
         final Version version = Version.V_1_0_0;
         assertEquals(
             version,
-            Version.indexCreated(
+            IndexMetadata.indexCreated(
                 Settings.builder().put(IndexMetadata.SETTING_INDEX_UUID, "foo").put(IndexMetadata.SETTING_VERSION_CREATED, version).build()
             )
         );
@@ -245,6 +245,26 @@ public void testOpenSearchMinIndexCompatVersion() {
         assertEquals(expected.revision, actual.revision);
     }
 
+    /** test first version of opensearch compatibility that does not support legacy versions */
+    public void testOpenSearchPreLegacyRemoval() {
+        Version opensearchVersion = Version.fromString("3.0.0");
+        int opensearchMajor = opensearchVersion.major;
+        List<Version> candidates = VersionUtils.allOpenSearchVersions();
+        Version expectedMinIndexCompat = VersionUtils.getFirstVersionOfMajor(candidates, opensearchMajor - 1);
+        Version actualMinIndexCompat = opensearchVersion.minimumIndexCompatibilityVersion();
+
+        Version expectedMinCompat = VersionUtils.lastFirstReleasedMinorFromMajor(VersionUtils.allOpenSearchVersions(), opensearchMajor - 1);
+        Version actualMinCompat = opensearchVersion.minimumCompatibilityVersion();
+        // since some legacy versions still support build (alpha, beta, RC) we check major minor revision only
+        assertEquals(expectedMinIndexCompat.major, actualMinIndexCompat.major);
+        assertEquals(expectedMinIndexCompat.minor, actualMinIndexCompat.minor);
+        assertEquals(expectedMinIndexCompat.revision, actualMinIndexCompat.revision);
+
+        assertEquals(expectedMinCompat.major, actualMinCompat.major);
+        assertEquals(expectedMinCompat.minor, actualMinCompat.minor);
+        assertEquals(expectedMinCompat.revision, actualMinCompat.revision);
+    }
+
     public void testToString() {
         assertEquals("2.0.0-beta1", Version.fromString("2.0.0-beta1").toString());
         assertEquals("5.0.0-alpha1", Version.fromId(5000001).toString());
diff --git a/server/src/test/java/org/opensearch/action/ActionModuleTests.java b/server/src/test/java/org/opensearch/action/ActionModuleTests.java
index 3193a8d953763..deb0bb58a5c4d 100644
--- a/server/src/test/java/org/opensearch/action/ActionModuleTests.java
+++ b/server/src/test/java/org/opensearch/action/ActionModuleTests.java
@@ -45,9 +45,12 @@
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.settings.SettingsModule;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.ActionPlugin.ActionHandler;
-
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestController;
 import org.opensearch.rest.RestHandler;
@@ -62,7 +65,9 @@
 import org.opensearch.usage.UsageService;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 import java.util.function.Supplier;
 
 import static java.util.Collections.emptyList;
@@ -122,7 +127,7 @@ protected FakeAction() {
         );
     }
 
-    public void testSetupRestHandlerContainsKnownBuiltin() {
+    public void testSetupRestHandlerContainsKnownBuiltin() throws IOException {
         SettingsModule settings = new SettingsModule(Settings.EMPTY);
         UsageService usageService = new UsageService();
         ActionModule actionModule = new ActionModule(
@@ -136,7 +141,9 @@ public void testSetupRestHandlerContainsKnownBuiltin() {
             null,
             null,
             usageService,
-            null
+            null,
+            new IdentityService(Settings.EMPTY, new ArrayList<>()),
+            new ExtensionsManager(Set.of())
         );
         actionModule.initRestHandlers(null);
         // At this point the easiest way to confirm that a handler is loaded is to try to register another one on top of it and to fail
@@ -192,6 +199,8 @@ public String getName() {
                 null,
                 null,
                 usageService,
+                null,
+                null,
                 null
             );
             Exception e = expectThrows(IllegalArgumentException.class, () -> actionModule.initRestHandlers(null));
@@ -241,6 +250,8 @@ public List<RestHandler> getRestHandlers(
                 null,
                 null,
                 usageService,
+                null,
+                null,
                 null
             );
             actionModule.initRestHandlers(null);
diff --git a/server/src/test/java/org/opensearch/action/ActionTests.java b/server/src/test/java/org/opensearch/action/ActionTests.java
index 9ed9ecffb134d..49cf15065ff45 100644
--- a/server/src/test/java/org/opensearch/action/ActionTests.java
+++ b/server/src/test/java/org/opensearch/action/ActionTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.action;
 
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.test.OpenSearchTestCase;
 
 public class ActionTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/action/DocWriteResponseTests.java b/server/src/test/java/org/opensearch/action/DocWriteResponseTests.java
index 30dcaf8d9c1c1..f432d13b10604 100644
--- a/server/src/test/java/org/opensearch/action/DocWriteResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/DocWriteResponseTests.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.action.DocWriteResponse.Result;
 import org.opensearch.action.support.replication.ReplicationResponse.ShardInfo;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/DynamicActionRegistryTests.java b/server/src/test/java/org/opensearch/action/DynamicActionRegistryTests.java
new file mode 100644
index 0000000000000..20c2b1f17124c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/DynamicActionRegistryTests.java
@@ -0,0 +1,150 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action;
+
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.main.MainAction;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.TransportAction;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.extensions.action.ExtensionAction;
+import org.opensearch.extensions.action.ExtensionTransportAction;
+import org.opensearch.extensions.rest.RestSendToExtensionAction;
+import org.opensearch.rest.NamedRoute;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskManager;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+
+import static org.mockito.Mockito.mock;
+
+public class DynamicActionRegistryTests extends OpenSearchTestCase {
+
+    public void testDynamicActionRegistry() {
+        ActionFilters emptyFilters = new ActionFilters(Collections.emptySet());
+        Map<ActionType, TransportAction> testMap = Map.of(TestAction.INSTANCE, new TestTransportAction("test-action", emptyFilters, null));
+
+        DynamicActionRegistry dynamicActionRegistry = new DynamicActionRegistry();
+        dynamicActionRegistry.registerUnmodifiableActionMap(testMap);
+
+        // Should contain the immutable map entry
+        assertNotNull(dynamicActionRegistry.get(TestAction.INSTANCE));
+        // Should not contain anything not added
+        assertNull(dynamicActionRegistry.get(MainAction.INSTANCE));
+
+        // ExtensionsAction not yet registered
+        ExtensionAction testExtensionAction = new ExtensionAction("extensionId", "actionName");
+        ExtensionTransportAction testExtensionTransportAction = new ExtensionTransportAction("test-action", emptyFilters, null, null);
+        assertNull(dynamicActionRegistry.get(testExtensionAction));
+
+        // Register an extension action
+        // Should insert without problem
+        try {
+            dynamicActionRegistry.registerDynamicAction(testExtensionAction, testExtensionTransportAction);
+        } catch (Exception e) {
+            fail("Should not have thrown exception registering action: " + e);
+        }
+        assertEquals(testExtensionTransportAction, dynamicActionRegistry.get(testExtensionAction));
+
+        // Should fail inserting twice
+        IllegalArgumentException ex = assertThrows(
+            IllegalArgumentException.class,
+            () -> dynamicActionRegistry.registerDynamicAction(testExtensionAction, testExtensionTransportAction)
+        );
+        assertEquals("action [actionName] already registered", ex.getMessage());
+        // Should remove without problem
+        try {
+            dynamicActionRegistry.unregisterDynamicAction(testExtensionAction);
+        } catch (Exception e) {
+            fail("Should not have thrown exception unregistering action: " + e);
+        }
+        // Should have been removed
+        assertNull(dynamicActionRegistry.get(testExtensionAction));
+
+        // Should fail removing twice
+        ex = assertThrows(IllegalArgumentException.class, () -> dynamicActionRegistry.unregisterDynamicAction(testExtensionAction));
+        assertEquals("action [actionName] was not registered", ex.getMessage());
+    }
+
+    public void testDynamicActionRegistryWithNamedRoutes() {
+        RestSendToExtensionAction action = mock(RestSendToExtensionAction.class);
+        RestSendToExtensionAction action2 = mock(RestSendToExtensionAction.class);
+        NamedRoute r1 = new NamedRoute.Builder().method(RestRequest.Method.GET).path("/foo").uniqueName("foo").build();
+        NamedRoute r2 = new NamedRoute.Builder().method(RestRequest.Method.PUT).path("/bar").uniqueName("bar").build();
+
+        DynamicActionRegistry registry = new DynamicActionRegistry();
+        registry.registerDynamicRoute(r1, action);
+        registry.registerDynamicRoute(r2, action2);
+
+        assertTrue(registry.isActionRegistered("foo"));
+        assertTrue(registry.isActionRegistered("bar"));
+
+        registry.unregisterDynamicRoute(r2);
+
+        assertTrue(registry.isActionRegistered("foo"));
+        assertFalse(registry.isActionRegistered("bar"));
+    }
+
+    public void testDynamicActionRegistryWithNamedRoutesAndLegacyActionNames() {
+        RestSendToExtensionAction action = mock(RestSendToExtensionAction.class);
+        RestSendToExtensionAction action2 = mock(RestSendToExtensionAction.class);
+        NamedRoute r1 = new NamedRoute.Builder().method(RestRequest.Method.GET)
+            .path("/foo")
+            .uniqueName("foo")
+            .legacyActionNames(Set.of("cluster:admin/opensearch/abc/foo"))
+            .build();
+        NamedRoute r2 = new NamedRoute.Builder().method(RestRequest.Method.PUT)
+            .path("/bar")
+            .uniqueName("bar")
+            .legacyActionNames(Set.of("cluster:admin/opensearch/xyz/bar"))
+            .build();
+
+        DynamicActionRegistry registry = new DynamicActionRegistry();
+        registry.registerDynamicRoute(r1, action);
+        registry.registerDynamicRoute(r2, action2);
+
+        assertTrue(registry.isActionRegistered("cluster:admin/opensearch/abc/foo"));
+        assertTrue(registry.isActionRegistered("cluster:admin/opensearch/xyz/bar"));
+
+        registry.unregisterDynamicRoute(r2);
+
+        assertTrue(registry.isActionRegistered("cluster:admin/opensearch/abc/foo"));
+        assertFalse(registry.isActionRegistered("cluster:admin/opensearch/xyz/bar"));
+    }
+
+    private static final class TestAction extends ActionType<ActionResponse> {
+        public static final TestAction INSTANCE = new TestAction();
+
+        private TestAction() {
+            super("test-action", new Writeable.Reader<ActionResponse>() {
+                @Override
+                public ActionResponse read(StreamInput in) throws IOException {
+                    return null;
+                }
+            });
+        }
+    };
+
+    private static final class TestTransportAction extends TransportAction<ActionRequest, ActionResponse> {
+        protected TestTransportAction(String actionName, ActionFilters actionFilters, TaskManager taskManager) {
+            super(actionName, actionFilters, taskManager);
+        }
+
+        @Override
+        protected void doExecute(Task task, ActionRequest request, ActionListener<ActionResponse> listener) {}
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/OriginalIndicesTests.java b/server/src/test/java/org/opensearch/action/OriginalIndicesTests.java
index c7ea8230fc5a9..4598ce27d8682 100644
--- a/server/src/test/java/org/opensearch/action/OriginalIndicesTests.java
+++ b/server/src/test/java/org/opensearch/action/OriginalIndicesTests.java
@@ -36,7 +36,7 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/RenamedTimeoutRequestParameterTests.java b/server/src/test/java/org/opensearch/action/RenamedTimeoutRequestParameterTests.java
new file mode 100644
index 0000000000000..be86c2d335ea2
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/RenamedTimeoutRequestParameterTests.java
@@ -0,0 +1,629 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.action.admin.cluster.RestCleanupRepositoryAction;
+import org.opensearch.rest.action.admin.cluster.RestCloneSnapshotAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterGetSettingsAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterHealthAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterRerouteAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterStateAction;
+import org.opensearch.rest.action.admin.cluster.RestClusterUpdateSettingsAction;
+import org.opensearch.rest.action.admin.cluster.RestCreateSnapshotAction;
+import org.opensearch.rest.action.admin.cluster.RestDeleteRepositoryAction;
+import org.opensearch.rest.action.admin.cluster.RestDeleteSnapshotAction;
+import org.opensearch.rest.action.admin.cluster.RestDeleteStoredScriptAction;
+import org.opensearch.rest.action.admin.cluster.RestGetRepositoriesAction;
+import org.opensearch.rest.action.admin.cluster.RestGetSnapshotsAction;
+import org.opensearch.rest.action.admin.cluster.RestGetStoredScriptAction;
+import org.opensearch.rest.action.admin.cluster.RestPutRepositoryAction;
+import org.opensearch.rest.action.admin.cluster.RestPutStoredScriptAction;
+import org.opensearch.rest.action.admin.cluster.RestRestoreSnapshotAction;
+import org.opensearch.rest.action.admin.cluster.RestSnapshotsStatusAction;
+import org.opensearch.rest.action.admin.cluster.RestVerifyRepositoryAction;
+import org.opensearch.rest.action.admin.cluster.dangling.RestDeleteDanglingIndexAction;
+import org.opensearch.rest.action.admin.cluster.dangling.RestImportDanglingIndexAction;
+import org.opensearch.rest.action.admin.indices.RestAddIndexBlockAction;
+import org.opensearch.rest.action.admin.indices.RestCloseIndexAction;
+import org.opensearch.rest.action.admin.indices.RestCreateIndexAction;
+import org.opensearch.rest.action.admin.indices.RestDeleteComponentTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestDeleteComposableIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestDeleteIndexAction;
+import org.opensearch.rest.action.admin.indices.RestDeleteIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestGetComponentTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestGetComposableIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestGetIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestGetIndicesAction;
+import org.opensearch.rest.action.admin.indices.RestGetMappingAction;
+import org.opensearch.rest.action.admin.indices.RestGetSettingsAction;
+import org.opensearch.rest.action.admin.indices.RestIndexDeleteAliasesAction;
+import org.opensearch.rest.action.admin.indices.RestIndexPutAliasAction;
+import org.opensearch.rest.action.admin.indices.RestIndicesAliasesAction;
+import org.opensearch.rest.action.admin.indices.RestOpenIndexAction;
+import org.opensearch.rest.action.admin.indices.RestPutComponentTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestPutComposableIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestPutIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestPutMappingAction;
+import org.opensearch.rest.action.admin.indices.RestResizeHandler;
+import org.opensearch.rest.action.admin.indices.RestRolloverIndexAction;
+import org.opensearch.rest.action.admin.indices.RestSimulateIndexTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestSimulateTemplateAction;
+import org.opensearch.rest.action.admin.indices.RestUpdateSettingsAction;
+import org.opensearch.rest.action.cat.RestAllocationAction;
+import org.opensearch.rest.action.cat.RestClusterManagerAction;
+import org.opensearch.rest.action.cat.RestIndicesAction;
+import org.opensearch.rest.action.cat.RestMasterAction;
+import org.opensearch.rest.action.cat.RestNodeAttrsAction;
+import org.opensearch.rest.action.cat.RestNodesAction;
+import org.opensearch.rest.action.cat.RestPendingClusterTasksAction;
+import org.opensearch.rest.action.cat.RestPluginsAction;
+import org.opensearch.rest.action.cat.RestRepositoriesAction;
+import org.opensearch.rest.action.cat.RestSegmentsAction;
+import org.opensearch.rest.action.cat.RestShardsAction;
+import org.opensearch.rest.action.cat.RestSnapshotAction;
+import org.opensearch.rest.action.cat.RestTemplatesAction;
+import org.opensearch.rest.action.cat.RestThreadPoolAction;
+import org.opensearch.rest.action.ingest.RestDeletePipelineAction;
+import org.opensearch.rest.action.ingest.RestGetPipelineAction;
+import org.opensearch.rest.action.ingest.RestPutPipelineAction;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.rest.FakeRestRequest;
+import org.opensearch.threadpool.TestThreadPool;
+import org.junit.After;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_READ_ONLY_SETTING;
+import static org.hamcrest.Matchers.containsString;
+
+/**
+ * As of 2.0, the request parameter 'master_timeout' in all applicable REST APIs is deprecated,
+ * and alternative parameter 'cluster_manager_timeout' is added.
+ * The tests are used to validate the behavior about the renamed request parameter.
+ * Remove the test after removing MASTER_ROLE and 'master_timeout'.
+ */
+public class RenamedTimeoutRequestParameterTests extends OpenSearchTestCase {
+    private final TestThreadPool threadPool = new TestThreadPool(RenamedTimeoutRequestParameterTests.class.getName());
+    private final NodeClient client = new NodeClient(Settings.EMPTY, threadPool);
+
+    private static final String DUPLICATE_PARAMETER_ERROR_MESSAGE =
+        "Please only use one of the request parameters [master_timeout, cluster_manager_timeout].";
+
+    @After
+    public void terminateThreadPool() {
+        terminate(threadPool);
+    }
+
+    public void testNoWarningsForNewParam() {
+        BaseRestHandler.parseDeprecatedMasterTimeoutParameter(getMasterNodeRequest(), getRestRequestWithNewParam());
+    }
+
+    public void testBothParamsNotValid() {
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> BaseRestHandler.parseDeprecatedMasterTimeoutParameter(getMasterNodeRequest(), getRestRequestWithBothParams())
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatAllocation() {
+        RestAllocationAction action = new RestAllocationAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatIndices() {
+        RestIndicesAction action = new RestIndicesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatClusterManager() {
+        RestClusterManagerAction action = new RestClusterManagerAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatMaster() {
+        RestMasterAction action = new RestMasterAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatNodeattrs() {
+        RestNodeAttrsAction action = new RestNodeAttrsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatNodes() {
+        RestNodesAction action = new RestNodesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatPendingTasks() {
+        RestPendingClusterTasksAction action = new RestPendingClusterTasksAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatPlugins() {
+        RestPluginsAction action = new RestPluginsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatRepositories() {
+        RestRepositoriesAction action = new RestRepositoriesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatShards() {
+        RestShardsAction action = new RestShardsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatSnapshots() {
+        RestSnapshotAction action = new RestSnapshotAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatTemplates() {
+        RestTemplatesAction action = new RestTemplatesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatThreadPool() {
+        RestThreadPoolAction action = new RestThreadPoolAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCatSegments() {
+        RestSegmentsAction action = new RestSegmentsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterHealth() {
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> RestClusterHealthAction.fromRequest(getRestRequestWithBodyWithBothParams())
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterReroute() throws IOException {
+        final SettingsFilter filter = new SettingsFilter(Collections.singleton("foo.filtered"));
+        RestClusterRerouteAction action = new RestClusterRerouteAction(filter);
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterState() throws IOException {
+        final SettingsFilter filter = new SettingsFilter(Collections.singleton("foo.filtered"));
+        RestClusterStateAction action = new RestClusterStateAction(filter);
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterGetSettings() throws IOException {
+        final SettingsFilter filter = new SettingsFilter(Collections.singleton("foo.filtered"));
+        RestClusterGetSettingsAction action = new RestClusterGetSettingsAction(null, null, filter);
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterUpdateSettings() throws IOException {
+        RestClusterUpdateSettingsAction action = new RestClusterUpdateSettingsAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testClusterPendingTasks() {
+        RestPendingClusterTasksAction action = new RestPendingClusterTasksAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testAddIndexBlock() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        request.params().put("block", "metadata");
+        NodeClient client = new NodeClient(Settings.builder().put(INDEX_READ_ONLY_SETTING.getKey(), Boolean.FALSE).build(), threadPool);
+        RestAddIndexBlockAction action = new RestAddIndexBlockAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCloseIndex() {
+        RestCloseIndexAction action = new RestCloseIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCreateIndex() {
+        RestCreateIndexAction action = new RestCreateIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteIndex() {
+        RestDeleteIndexAction action = new RestDeleteIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetIndices() {
+        RestGetIndicesAction action = new RestGetIndicesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetMapping() {
+        RestGetMappingAction action = new RestGetMappingAction(threadPool);
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetSettings() {
+        RestGetSettingsAction action = new RestGetSettingsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testIndexDeleteAliases() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        request.params().put("name", "*");
+        request.params().put("index", "test");
+        RestIndexDeleteAliasesAction action = new RestIndexDeleteAliasesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testIndexPutAlias() {
+        RestIndexPutAliasAction action = new RestIndexPutAliasAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testIndicesAliases() {
+        RestIndicesAliasesAction action = new RestIndicesAliasesAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testOpenIndex() {
+        RestOpenIndexAction action = new RestOpenIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutMapping() {
+        RestPutMappingAction action = new RestPutMappingAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testShrinkIndex() {
+        RestResizeHandler.RestShrinkIndexAction action = new RestResizeHandler.RestShrinkIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testSplitIndex() {
+        RestResizeHandler.RestSplitIndexAction action = new RestResizeHandler.RestSplitIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCloneIndex() {
+        RestResizeHandler.RestCloneIndexAction action = new RestResizeHandler.RestCloneIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testRolloverIndex() {
+        RestRolloverIndexAction action = new RestRolloverIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testUpdateSettings() {
+        RestUpdateSettingsAction action = new RestUpdateSettingsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteDanglingIndex() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        request.params().put("index_uuid", "test");
+        RestDeleteDanglingIndexAction action = new RestDeleteDanglingIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testImportDanglingIndex() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        request.params().put("index_uuid", "test");
+        RestImportDanglingIndexAction action = new RestImportDanglingIndexAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteComponentTemplate() {
+        RestDeleteComponentTemplateAction action = new RestDeleteComponentTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteComposableIndexTemplate() {
+        RestDeleteComposableIndexTemplateAction action = new RestDeleteComposableIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteIndexTemplate() {
+        RestDeleteIndexTemplateAction action = new RestDeleteIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetComponentTemplate() {
+        RestGetComponentTemplateAction action = new RestGetComponentTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetComposableIndexTemplate() {
+        RestGetComposableIndexTemplateAction action = new RestGetComposableIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetIndexTemplate() {
+        RestGetIndexTemplateAction action = new RestGetIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutComponentTemplate() {
+        RestPutComponentTemplateAction action = new RestPutComponentTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutComposableIndexTemplate() {
+        RestPutComposableIndexTemplateAction action = new RestPutComposableIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutIndexTemplate() {
+        RestPutIndexTemplateAction action = new RestPutIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testSimulateIndexTemplate() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", randomFrom("1h", "2m"));
+        request.params().put("master_timeout", "3s");
+        request.params().put("name", "test");
+        RestSimulateIndexTemplateAction action = new RestSimulateIndexTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testSimulateTemplate() {
+        RestSimulateTemplateAction action = new RestSimulateTemplateAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCleanupRepository() {
+        RestCleanupRepositoryAction action = new RestCleanupRepositoryAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCloneSnapshot() {
+        RestCloneSnapshotAction action = new RestCloneSnapshotAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testCreateSnapshot() {
+        RestCreateSnapshotAction action = new RestCreateSnapshotAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteRepository() {
+        RestDeleteRepositoryAction action = new RestDeleteRepositoryAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteSnapshot() {
+        RestDeleteSnapshotAction action = new RestDeleteSnapshotAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetRepositories() {
+        final SettingsFilter filter = new SettingsFilter(Collections.singleton("foo.filtered"));
+        RestGetRepositoriesAction action = new RestGetRepositoriesAction(filter);
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetSnapshots() {
+        RestGetSnapshotsAction action = new RestGetSnapshotsAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutRepository() {
+        RestPutRepositoryAction action = new RestPutRepositoryAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testRestoreSnapshot() {
+        RestRestoreSnapshotAction action = new RestRestoreSnapshotAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testSnapshotsStatus() {
+        RestSnapshotsStatusAction action = new RestSnapshotsStatusAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testVerifyRepository() {
+        RestVerifyRepositoryAction action = new RestVerifyRepositoryAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeletePipeline() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        request.params().put("id", "test");
+        RestDeletePipelineAction action = new RestDeletePipelineAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetPipeline() {
+        RestGetPipelineAction action = new RestGetPipelineAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutPipeline() {
+        FakeRestRequest request = getFakeRestRequestWithBody();
+        request.params().put("cluster_manager_timeout", "2m");
+        request.params().put("master_timeout", "3s");
+        request.params().put("id", "test");
+        RestPutPipelineAction action = new RestPutPipelineAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(request, client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testDeleteStoredScript() {
+        RestDeleteStoredScriptAction action = new RestDeleteStoredScriptAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testGetStoredScript() {
+        RestGetStoredScriptAction action = new RestGetStoredScriptAction();
+        Exception e = assertThrows(OpenSearchParseException.class, () -> action.prepareRequest(getRestRequestWithBothParams(), client));
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+    }
+
+    public void testPutStoredScript() {
+        RestPutStoredScriptAction action = new RestPutStoredScriptAction();
+        Exception e = assertThrows(
+            OpenSearchParseException.class,
+            () -> action.prepareRequest(getRestRequestWithBodyWithBothParams(), client)
+        );
+        assertThat(e.getMessage(), containsString(DUPLICATE_PARAMETER_ERROR_MESSAGE));
+        assertWarnings("empty templates should no longer be used");
+    }
+
+    private ClusterManagerNodeRequest getMasterNodeRequest() {
+        return new ClusterManagerNodeRequest() {
+            @Override
+            public ActionRequestValidationException validate() {
+                return null;
+            }
+        };
+    }
+
+    private FakeRestRequest getRestRequestWithBothParams() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "1h");
+        request.params().put("master_timeout", "3s");
+        return request;
+    }
+
+    private FakeRestRequest getRestRequestWithDeprecatedParam() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("master_timeout", "3s");
+        return request;
+    }
+
+    private FakeRestRequest getRestRequestWithNewParam() {
+        FakeRestRequest request = new FakeRestRequest();
+        request.params().put("cluster_manager_timeout", "2m");
+        return request;
+    }
+
+    private FakeRestRequest getRestRequestWithBodyWithBothParams() {
+        FakeRestRequest request = getFakeRestRequestWithBody();
+        request.params().put("cluster_manager_timeout", "2m");
+        request.params().put("master_timeout", "3s");
+        return request;
+    }
+
+    private FakeRestRequest getFakeRestRequestWithBody() {
+        return new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY).withContent(new BytesArray("{}"), MediaTypeRegistry.JSON).build();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/ShardOperationFailedExceptionTests.java b/server/src/test/java/org/opensearch/action/ShardOperationFailedExceptionTests.java
index 0b926c788d35e..2844fd6c837c1 100644
--- a/server/src/test/java/org/opensearch/action/ShardOperationFailedExceptionTests.java
+++ b/server/src/test/java/org/opensearch/action/ShardOperationFailedExceptionTests.java
@@ -33,9 +33,10 @@
 package org.opensearch.action;
 
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/ShardValidateQueryRequestTests.java b/server/src/test/java/org/opensearch/action/ShardValidateQueryRequestTests.java
index 726f77b0ddf13..3528e53ae786d 100644
--- a/server/src/test/java/org/opensearch/action/ShardValidateQueryRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/ShardValidateQueryRequestTests.java
@@ -34,12 +34,12 @@
 import org.opensearch.action.admin.indices.validate.query.ShardValidateQueryRequest;
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryRequest;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.internal.AliasFilter;
diff --git a/server/src/test/java/org/opensearch/action/TaskOperationFailureTests.java b/server/src/test/java/org/opensearch/action/TaskOperationFailureTests.java
index b07e0663a0c9f..b9db1c46c3ccf 100644
--- a/server/src/test/java/org/opensearch/action/TaskOperationFailureTests.java
+++ b/server/src/test/java/org/opensearch/action/TaskOperationFailureTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainActionTests.java
index 59a4a05f0db8e..d01265edbe874 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplainActionTests.java
@@ -44,10 +44,9 @@
 import org.opensearch.cluster.routing.allocation.ShardAllocationDecision;
 import org.opensearch.cluster.routing.allocation.allocator.ShardsAllocator;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 
@@ -138,7 +137,7 @@ public ShardAllocationDecision decideShardAllocation(ShardRouting shard, Routing
                 + "\"},\"explanation\":\""
                 + explanation
                 + "\"}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanationTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanationTests.java
index e28306c13110b..21bd4333dd881 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanationTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/allocation/ClusterAllocationExplanationTests.java
@@ -43,14 +43,13 @@
 import org.opensearch.cluster.routing.allocation.MoveDecision;
 import org.opensearch.cluster.routing.allocation.ShardAllocationDecision;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static java.util.Collections.emptyMap;
@@ -109,7 +108,7 @@ public void testExplanationToXContent() throws Exception {
                 + "\",\"weight_ranking\":3},\"can_remain_on_current_node\":\"yes\",\"can_rebalance_cluster\":\"yes\","
                 + "\"can_rebalance_to_other_node\":\"no\",\"rebalance_explanation\":\"cannot rebalance as no target node exists "
                 + "that can both allocate this shard and improve the cluster balance\"}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequestTests.java
index 8da65ba13b9cb..529ed8c1b62cc 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequestTests.java
@@ -40,8 +40,8 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -163,7 +163,7 @@ public void testResolve() {
                 IllegalArgumentException.class,
                 () -> makeRequestWithNodeDescriptions("not-a-node").resolveVotingConfigExclusions(clusterState)
             ).getMessage(),
-            equalTo("add voting config exclusions request for [not-a-node] matched no master-eligible nodes")
+            equalTo("add voting config exclusions request for [not-a-node] matched no cluster-manager-eligible nodes")
         );
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
@@ -450,6 +450,64 @@ public void testResolveAndCheckMaximum() {
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
 
+    // As of 2.0, MASTER_ROLE is deprecated to promote inclusive language.
+    // Validate node with MASTER_ROLE can be resolved by resolveVotingConfigExclusions() like before.
+    // The following 3 tests assign nodes by description, id and name respectively.
+    public void testResolveByNodeDescriptionWithDeprecatedMasterRole() {
+        final DiscoveryNode localNode = new DiscoveryNode(
+            "local",
+            "local",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+        final VotingConfigExclusion localNodeExclusion = new VotingConfigExclusion(localNode);
+
+        final ClusterState clusterState = ClusterState.builder(new ClusterName("cluster"))
+            .nodes(new Builder().add(localNode).localNodeId(localNode.getId()))
+            .build();
+
+        assertThat(makeRequestWithNodeDescriptions("_local").resolveVotingConfigExclusions(clusterState), contains(localNodeExclusion));
+        allowedWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
+    }
+
+    public void testResolveByNodeIdWithDeprecatedMasterRole() {
+        final DiscoveryNode node = new DiscoveryNode(
+            "nodeName",
+            "nodeId",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+        final VotingConfigExclusion nodeExclusion = new VotingConfigExclusion(node);
+
+        final ClusterState clusterState = ClusterState.builder(new ClusterName("cluster")).nodes(new Builder().add(node)).build();
+
+        assertThat(
+            new AddVotingConfigExclusionsRequest(Strings.EMPTY_ARRAY, new String[] { "nodeId" }, Strings.EMPTY_ARRAY, TimeValue.ZERO)
+                .resolveVotingConfigExclusions(clusterState),
+            contains(nodeExclusion)
+        );
+    }
+
+    public void testResolveByNodeNameWithDeprecatedMasterRole() {
+        final DiscoveryNode node = new DiscoveryNode(
+            "nodeName",
+            "nodeId",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+        final VotingConfigExclusion nodeExclusion = new VotingConfigExclusion(node);
+
+        final ClusterState clusterState = ClusterState.builder(new ClusterName("cluster")).nodes(new Builder().add(node)).build();
+
+        assertThat(new AddVotingConfigExclusionsRequest("nodeName").resolveVotingConfigExclusions(clusterState), contains(nodeExclusion));
+    }
+
     private static AddVotingConfigExclusionsRequest makeRequestWithNodeDescriptions(String... nodeDescriptions) {
         return new AddVotingConfigExclusionsRequest(
             nodeDescriptions,
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
index a570db040a805..a015e671f4872 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
 import org.opensearch.action.support.ActionFilters;
@@ -49,12 +48,14 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -139,7 +140,8 @@ public void setupForTest() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
 
         final Settings.Builder nodeSettingsBuilder = Settings.builder();
@@ -175,7 +177,7 @@ public void setupForTest() {
                     .add(otherNode2)
                     .add(otherDataNode)
                     .localNodeId(localNode.getId())
-                    .masterNodeId(localNode.getId())
+                    .clusterManagerNodeId(localNode.getId())
             )
                 .metadata(
                     Metadata.builder()
@@ -252,7 +254,7 @@ public void testWithdrawsVotesFromNodesMatchingWildcard() throws InterruptedExce
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
 
-    public void testWithdrawsVotesFromAllMasterEligibleNodes() throws InterruptedException {
+    public void testWithdrawsVotesFromAllClusterManagerEligibleNodes() throws InterruptedException {
         final CountDownLatch countDownLatch = new CountDownLatch(2);
 
         clusterStateObserver.waitForNextChange(new AdjustConfigurationForExclusions(countDownLatch));
@@ -344,19 +346,19 @@ public void testReturnsErrorIfNoMatchingNodeDescriptions() throws InterruptedExc
         assertThat(rootCause, instanceOf(IllegalArgumentException.class));
         assertThat(
             rootCause.getMessage(),
-            equalTo("add voting config exclusions request for [not-a-node] matched no master-eligible nodes")
+            equalTo("add voting config exclusions request for [not-a-node] matched no cluster-manager-eligible nodes")
         );
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
 
-    public void testOnlyMatchesMasterEligibleNodes() throws InterruptedException {
+    public void testOnlyMatchesClusterManagerEligibleNodes() throws InterruptedException {
         final CountDownLatch countDownLatch = new CountDownLatch(1);
         final SetOnce<TransportException> exceptionHolder = new SetOnce<>();
 
         transportService.sendRequest(
             localNode,
             AddVotingConfigExclusionsAction.NAME,
-            makeRequestWithNodeDescriptions("_all", "master:false"),
+            makeRequestWithNodeDescriptions("_all", "cluster_manager:false"),
             expectError(e -> {
                 exceptionHolder.set(e);
                 countDownLatch.countDown();
@@ -368,7 +370,7 @@ public void testOnlyMatchesMasterEligibleNodes() throws InterruptedException {
         assertThat(rootCause, instanceOf(IllegalArgumentException.class));
         assertThat(
             rootCause.getMessage(),
-            equalTo("add voting config exclusions request for [_all, master:false] matched no master-eligible nodes")
+            equalTo("add voting config exclusions request for [_all, cluster_manager:false] matched no cluster-manager-eligible nodes")
         );
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
@@ -386,7 +388,9 @@ public void testExcludeAbsentNodesByNodeIds() throws InterruptedException {
                 Strings.EMPTY_ARRAY,
                 TimeValue.timeValueSeconds(30)
             ),
-            expectSuccess(e -> { countDownLatch.countDown(); })
+            expectSuccess(e -> {
+                countDownLatch.countDown();
+            })
         );
 
         assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
@@ -430,7 +434,9 @@ public void testExcludeAbsentNodesByNodeNames() throws InterruptedException {
             localNode,
             AddVotingConfigExclusionsAction.NAME,
             new AddVotingConfigExclusionsRequest("absent_node"),
-            expectSuccess(e -> { countDownLatch.countDown(); })
+            expectSuccess(e -> {
+                countDownLatch.countDown();
+            })
         );
 
         assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
@@ -692,7 +698,7 @@ private static class AdjustConfigurationForExclusions implements Listener {
 
         @Override
         public void onNewClusterState(ClusterState state) {
-            clusterService.getMasterService().submitStateUpdateTask("reconfiguration", new ClusterStateUpdateTask() {
+            clusterService.getClusterManagerService().submitStateUpdateTask("reconfiguration", new ClusterStateUpdateTask() {
                 @Override
                 public ClusterState execute(ClusterState currentState) {
                     assertThat(currentState, sameInstance(state));
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
index 604eee4763c89..10e4ab6388be4 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
 import org.opensearch.action.support.ActionFilters;
@@ -45,10 +44,12 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -111,7 +112,8 @@ public void setupForTest() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
 
         new TransportClearVotingConfigExclusionsAction(
@@ -126,7 +128,11 @@ public void setupForTest() {
         transportService.acceptIncomingRequests();
 
         final ClusterState.Builder builder = builder(new ClusterName("cluster")).nodes(
-            new Builder().add(localNode).add(otherNode1).add(otherNode2).localNodeId(localNode.getId()).masterNodeId(localNode.getId())
+            new Builder().add(localNode)
+                .add(otherNode1)
+                .add(otherNode2)
+                .localNodeId(localNode.getId())
+                .clusterManagerNodeId(localNode.getId())
         );
         builder.metadata(
             Metadata.builder()
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelperTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelperTests.java
new file mode 100644
index 0000000000000..c71d30ccac2b8
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/VotingConfigExclusionsHelperTests.java
@@ -0,0 +1,123 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.configuration;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.BeforeClass;
+
+import java.util.Set;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singleton;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.addExclusionAndGetState;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.clearExclusionsAndGetState;
+import static org.opensearch.action.admin.cluster.configuration.VotingConfigExclusionsHelper.resolveVotingConfigExclusionsAndCheckMaximum;
+
+public class VotingConfigExclusionsHelperTests extends OpenSearchTestCase {
+
+    private static DiscoveryNode localNode, otherNode1, otherNode2, otherDataNode;
+    private static CoordinationMetadata.VotingConfigExclusion localNodeExclusion, otherNode1Exclusion, otherNode2Exclusion;
+    private static ClusterState initialClusterState;
+
+    public void testAddExclusionAndGetState() {
+        ClusterState updatedState = addExclusionAndGetState(initialClusterState, Set.of(localNodeExclusion), 2);
+        assertTrue(updatedState.coordinationMetadata().getVotingConfigExclusions().contains(localNodeExclusion));
+        assertEquals(1, updatedState.coordinationMetadata().getVotingConfigExclusions().size());
+    }
+
+    public void testResolveVotingConfigExclusions() {
+        AddVotingConfigExclusionsRequest request = new AddVotingConfigExclusionsRequest(
+            Strings.EMPTY_ARRAY,
+            new String[] { "other1" },
+            Strings.EMPTY_ARRAY,
+            TimeValue.timeValueSeconds(30)
+        );
+        Set<CoordinationMetadata.VotingConfigExclusion> votingConfigExclusions = resolveVotingConfigExclusionsAndCheckMaximum(
+            request,
+            initialClusterState,
+            10
+        );
+        assertEquals(1, votingConfigExclusions.size());
+        assertTrue(votingConfigExclusions.contains(otherNode1Exclusion));
+    }
+
+    public void testResolveVotingConfigExclusionFailsWhenLimitExceeded() {
+        AddVotingConfigExclusionsRequest request = new AddVotingConfigExclusionsRequest(
+            Strings.EMPTY_ARRAY,
+            new String[] { "other1", "other2" },
+            Strings.EMPTY_ARRAY,
+            TimeValue.timeValueSeconds(30)
+        );
+        expectThrows(IllegalArgumentException.class, () -> resolveVotingConfigExclusionsAndCheckMaximum(request, initialClusterState, 1));
+    }
+
+    public void testClearExclusionAndGetState() {
+        ClusterState updatedState = addExclusionAndGetState(initialClusterState, Set.of(localNodeExclusion), 2);
+        assertTrue(updatedState.coordinationMetadata().getVotingConfigExclusions().contains(localNodeExclusion));
+        updatedState = clearExclusionsAndGetState(updatedState);
+        assertTrue(updatedState.coordinationMetadata().getVotingConfigExclusions().isEmpty());
+    }
+
+    @BeforeClass
+    public static void createBaseClusterState() {
+        localNode = makeDiscoveryNode("local");
+        localNodeExclusion = new CoordinationMetadata.VotingConfigExclusion(localNode);
+        otherNode1 = makeDiscoveryNode("other1");
+        otherNode1Exclusion = new CoordinationMetadata.VotingConfigExclusion(otherNode1);
+        otherNode2 = makeDiscoveryNode("other2");
+        otherNode2Exclusion = new CoordinationMetadata.VotingConfigExclusion(otherNode2);
+        otherDataNode = new DiscoveryNode("data", "data", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
+        final CoordinationMetadata.VotingConfiguration allNodesConfig = CoordinationMetadata.VotingConfiguration.of(
+            localNode,
+            otherNode1,
+            otherNode2
+        );
+        initialClusterState = ClusterState.builder(new ClusterName("cluster"))
+            .nodes(
+                new DiscoveryNodes.Builder().add(localNode)
+                    .add(otherNode1)
+                    .add(otherNode2)
+                    .add(otherDataNode)
+                    .localNodeId(localNode.getId())
+                    .clusterManagerNodeId(localNode.getId())
+            )
+            .metadata(
+                Metadata.builder()
+                    .coordinationMetadata(
+                        CoordinationMetadata.builder()
+                            .lastAcceptedConfiguration(allNodesConfig)
+                            .lastCommittedConfiguration(allNodesConfig)
+                            .build()
+                    )
+            )
+            .build();
+    }
+
+    private static DiscoveryNode makeDiscoveryNode(String name) {
+        return new DiscoveryNode(
+            name,
+            name,
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateRequestTests.java
new file mode 100644
index 0000000000000..f44d43597f50f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateRequestTests.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class DeleteDecommissionStateRequestTests extends OpenSearchTestCase {
+
+    public void testSerialization() throws IOException {
+        final DeleteDecommissionStateRequest originalRequest = new DeleteDecommissionStateRequest();
+
+        final DeleteDecommissionStateRequest cloneRequest;
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            originalRequest.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                cloneRequest = new DeleteDecommissionStateRequest(in);
+            }
+        }
+        assertEquals(cloneRequest.clusterManagerNodeTimeout(), originalRequest.clusterManagerNodeTimeout());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateResponseTests.java
new file mode 100644
index 0000000000000..085eda3e9d0e7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/DeleteDecommissionStateResponseTests.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class DeleteDecommissionStateResponseTests extends OpenSearchTestCase {
+
+    public void testSerialization() throws IOException {
+        final DeleteDecommissionStateResponse originalResponse = new DeleteDecommissionStateResponse(true);
+
+        final DeleteDecommissionStateResponse deserialized = copyWriteable(
+            originalResponse,
+            writableRegistry(),
+            DeleteDecommissionStateResponse::new
+        );
+        assertEquals(deserialized, originalResponse);
+
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestTests.java
new file mode 100644
index 0000000000000..973485e1917f7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateRequestTests.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class GetDecommissionStateRequestTests extends OpenSearchTestCase {
+    public void testSerialization() throws IOException {
+        String attributeName = "zone";
+        final GetDecommissionStateRequest originalRequest = new GetDecommissionStateRequest(attributeName);
+        final GetDecommissionStateRequest deserialized = copyWriteable(
+            originalRequest,
+            writableRegistry(),
+            GetDecommissionStateRequest::new
+        );
+        assertEquals(deserialized.attributeName(), originalRequest.attributeName());
+    }
+
+    public void testValidation() {
+        {
+            String attributeName = null;
+            final GetDecommissionStateRequest request = new GetDecommissionStateRequest(attributeName);
+            ActionRequestValidationException e = request.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("attribute name is missing"));
+        }
+        {
+            String attributeName = "";
+            final GetDecommissionStateRequest request = new GetDecommissionStateRequest(attributeName);
+            ActionRequestValidationException e = request.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("attribute name is missing"));
+        }
+        {
+            String attributeName = "zone";
+            final GetDecommissionStateRequest request = new GetDecommissionStateRequest(attributeName);
+            ActionRequestValidationException e = request.validate();
+            assertNull(e);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponseTests.java
new file mode 100644
index 0000000000000..86df8868bc769
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/get/GetDecommissionStateResponseTests.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.get;
+
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+
+public class GetDecommissionStateResponseTests extends AbstractXContentTestCase<GetDecommissionStateResponse> {
+    @Override
+    protected GetDecommissionStateResponse createTestInstance() {
+        DecommissionStatus status = null;
+        String attributeValue = null;
+        if (randomBoolean()) {
+            status = randomFrom(DecommissionStatus.values());
+            attributeValue = randomAlphaOfLength(10);
+        }
+        return new GetDecommissionStateResponse(attributeValue, status);
+    }
+
+    @Override
+    protected GetDecommissionStateResponse doParseInstance(XContentParser parser) throws IOException {
+        return GetDecommissionStateResponse.fromXContent(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return false;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestTests.java
new file mode 100644
index 0000000000000..8cd407b3aecf2
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionRequestTests.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class DecommissionRequestTests extends OpenSearchTestCase {
+
+    public void testSerialization() throws IOException {
+        String attributeName = "zone";
+        String attributeValue = "zone-1";
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+        final DecommissionRequest originalRequest = new DecommissionRequest(decommissionAttribute);
+
+        final DecommissionRequest deserialized = copyWriteable(originalRequest, writableRegistry(), DecommissionRequest::new);
+
+        assertEquals(deserialized.getDecommissionAttribute(), originalRequest.getDecommissionAttribute());
+        assertEquals(deserialized.getDelayTimeout(), originalRequest.getDelayTimeout());
+    }
+
+    public void testValidation() {
+        {
+            String attributeName = null;
+            String attributeValue = "test";
+            DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+
+            final DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+            ActionRequestValidationException e = request.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("attribute name is missing"));
+        }
+        {
+            String attributeName = "zone";
+            String attributeValue = "";
+            DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+
+            final DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+            ActionRequestValidationException e = request.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("attribute value is missing"));
+        }
+        {
+            String attributeName = "zone";
+            String attributeValue = "test";
+            DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+
+            final DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+            request.setNoDelay(true);
+            ActionRequestValidationException e = request.validate();
+            assertNull(e);
+            assertEquals(TimeValue.ZERO, request.getDelayTimeout());
+        }
+        {
+            String attributeName = "zone";
+            String attributeValue = "test";
+            DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+
+            final DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+            ActionRequestValidationException e = request.validate();
+            assertNull(e);
+            assertEquals(DecommissionRequest.DEFAULT_NODE_DRAINING_TIMEOUT, request.getDelayTimeout());
+        }
+        {
+            String attributeName = "zone";
+            String attributeValue = "test";
+            DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+
+            final DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+            request.setNoDelay(true);
+            request.setDelayTimeout(TimeValue.timeValueSeconds(30));
+            ActionRequestValidationException e = request.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("Invalid decommission request"));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponseTests.java
new file mode 100644
index 0000000000000..5ee5a5f3cf016
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/decommission/awareness/put/DecommissionResponseTests.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.decommission.awareness.put;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class DecommissionResponseTests extends OpenSearchTestCase {
+    public void testSerialization() throws IOException {
+        final DecommissionResponse originalRequest = new DecommissionResponse(true);
+        copyWriteable(originalRequest, writableRegistry(), DecommissionResponse::new);
+        // there are no fields so we're just checking that this doesn't throw anything
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestTests.java
index c84279a0782c3..62297960d3cb4 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthRequestTests.java
@@ -33,12 +33,13 @@
 package org.opensearch.action.admin.cluster.health;
 
 import org.opensearch.LegacyESVersion;
+import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -152,6 +153,23 @@ public void testBwcSerialization() throws Exception {
         }
     }
 
+    public void testValidation() {
+        ClusterHealthRequest clusterHealthRequest = randomRequest();
+        {
+            clusterHealthRequest.local(false);
+            clusterHealthRequest.ensureNodeWeighedIn(true);
+            ActionRequestValidationException e = clusterHealthRequest.validate();
+            assertNotNull(e);
+            assertTrue(e.getMessage().contains("not a local request to ensure local node commissioned or weighed in"));
+        }
+        {
+            clusterHealthRequest.local(true);
+            clusterHealthRequest.ensureNodeWeighedIn(false);
+            ActionRequestValidationException e = clusterHealthRequest.validate();
+            assertNull(e);
+        }
+    }
+
     private ClusterHealthRequest randomRequest() {
         ClusterHealthRequest request = new ClusterHealthRequest();
         request.waitForStatus(randomFrom(ClusterHealthStatus.values()));
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponsesTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponsesTests.java
index decad9d6f840e..189d03e48b782 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponsesTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponsesTests.java
@@ -44,21 +44,20 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.OpenSearchTestCase;
-
-import org.hamcrest.Matchers;
 import org.opensearch.test.VersionUtils;
+import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -112,11 +111,11 @@ public void testClusterHealth() throws IOException {
         assertThat(clusterHealth.getActiveShardsPercent(), is(allOf(greaterThanOrEqualTo(0.0), lessThanOrEqualTo(100.0))));
     }
 
-    public void testClusterHealthVerifyMasterNodeDiscovery() throws IOException {
+    public void testClusterHealthVerifyClusterManagerNodeDiscovery() throws IOException {
         DiscoveryNode localNode = new DiscoveryNode("node", OpenSearchTestCase.buildNewFakeTransportAddress(), Version.CURRENT);
-        // set the node information to verify master_node discovery in ClusterHealthResponse
+        // set the node information to verify cluster_manager_node discovery in ClusterHealthResponse
         ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
-            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).masterNodeId(localNode.getId()))
+            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).clusterManagerNodeId(localNode.getId()))
             .build();
         int pendingTasks = randomIntBetween(0, 200);
         int inFlight = randomIntBetween(0, 200);
@@ -132,7 +131,7 @@ public void testClusterHealthVerifyMasterNodeDiscovery() throws IOException {
             pendingTaskInQueueTime
         );
         clusterHealth = maybeSerialize(clusterHealth);
-        assertThat(clusterHealth.getClusterStateHealth().hasDiscoveredMaster(), Matchers.equalTo(true));
+        assertThat(clusterHealth.getClusterStateHealth().hasDiscoveredClusterManager(), Matchers.equalTo(true));
         assertClusterHealth(clusterHealth);
     }
 
@@ -146,7 +145,7 @@ private void assertClusterHealth(ClusterHealthResponse clusterHealth) {
         assertThat(clusterHealth.getUnassignedShards(), Matchers.equalTo(clusterStateHealth.getUnassignedShards()));
         assertThat(clusterHealth.getNumberOfNodes(), Matchers.equalTo(clusterStateHealth.getNumberOfNodes()));
         assertThat(clusterHealth.getNumberOfDataNodes(), Matchers.equalTo(clusterStateHealth.getNumberOfDataNodes()));
-        assertThat(clusterHealth.hasDiscoveredMaster(), Matchers.equalTo(clusterStateHealth.hasDiscoveredMaster()));
+        assertThat(clusterHealth.hasDiscoveredClusterManager(), Matchers.equalTo(clusterStateHealth.hasDiscoveredClusterManager()));
     }
 
     public void testVersionCompatibleSerialization() throws IOException {
@@ -194,9 +193,14 @@ public void testVersionCompatibleSerialization() throws IOException {
         out_gt_1_0.setVersion(new_version);
         clusterHealth.writeTo(out_gt_1_0);
 
+        int bytesStreamOutputCount = 1;
+        if (out_gt_1_0.getVersion().onOrAfter(Version.V_2_5_0)) {
+            bytesStreamOutputCount = 2;
+        }
+
         // The serialized output byte stream will not be same; and different by a boolean field "discovered_master"
         assertNotEquals(out_lt_1_0.size(), out_gt_1_0.size());
-        assertThat(out_gt_1_0.size() - out_lt_1_0.size(), Matchers.equalTo(1));
+        assertEquals(out_gt_1_0.size() - out_lt_1_0.size(), bytesStreamOutputCount);
 
         // Input stream constructed from Version 6_8 or less will not have field "discovered_master";
         // hence fallback to default as no value retained
@@ -222,13 +226,13 @@ ClusterHealthResponse maybeSerialize(ClusterHealthResponse clusterHealth) throws
         return clusterHealth;
     }
 
-    public void testParseFromXContentWithDiscoveredMasterField() throws IOException {
+    public void testParseFromXContentWithDiscoveredClusterManagerField() throws IOException {
         try (
             XContentParser parser = JsonXContent.jsonXContent.createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 "{\"cluster_name\":\"535799904437:7-1-3-node\",\"status\":\"green\","
-                    + "\"timed_out\":false,\"number_of_nodes\":6,\"number_of_data_nodes\":3,\"discovered_master\":false,"
+                    + "\"timed_out\":false,\"number_of_nodes\":6,\"number_of_data_nodes\":3,\"discovered_cluster_manager\":true,"
                     + "\"active_primary_shards\":4,\"active_shards\":5,\"relocating_shards\":0,\"initializing_shards\":0,"
                     + "\"unassigned_shards\":0,\"delayed_unassigned_shards\":0,\"number_of_pending_tasks\":0,"
                     + "\"number_of_in_flight_fetch\":0,\"task_max_waiting_in_queue_millis\":0,"
@@ -240,7 +244,66 @@ public void testParseFromXContentWithDiscoveredMasterField() throws IOException
             assertNotNull(clusterHealth);
             assertThat(clusterHealth.getClusterName(), Matchers.equalTo("535799904437:7-1-3-node"));
             assertThat(clusterHealth.getNumberOfNodes(), Matchers.equalTo(6));
-            assertThat(clusterHealth.hasDiscoveredMaster(), Matchers.equalTo(false));
+            assertThat(clusterHealth.hasDiscoveredClusterManager(), Matchers.equalTo(true));
+        }
+    }
+
+    public void testParseFromXContentWithoutDiscoveredClusterManagerField() throws IOException {
+        try (
+            XContentParser parser = JsonXContent.jsonXContent.createParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+                "{\"cluster_name\":\"535799904437:7-1-3-node\",\"status\":\"green\","
+                    + "\"timed_out\":false,\"number_of_nodes\":6,\"number_of_data_nodes\":3,"
+                    + "\"active_primary_shards\":4,\"active_shards\":5,\"relocating_shards\":0,\"initializing_shards\":0,"
+                    + "\"unassigned_shards\":0,\"delayed_unassigned_shards\":0,\"number_of_pending_tasks\":0,"
+                    + "\"number_of_in_flight_fetch\":0,\"task_max_waiting_in_queue_millis\":0,"
+                    + "\"active_shards_percent_as_number\":100}"
+            )
+        ) {
+            ClusterHealthResponse clusterHealth = ClusterHealthResponse.fromXContent(parser);
+            assertNotNull(clusterHealth);
+            assertThat(clusterHealth.getClusterName(), Matchers.equalTo("535799904437:7-1-3-node"));
+            assertThat(clusterHealth.getNumberOfNodes(), Matchers.equalTo(6));
+            assertThat(clusterHealth.hasDiscoveredClusterManager(), Matchers.equalTo(false));
+        }
+    }
+
+    /**
+     * Validate the ClusterHealthResponse can be parsed from JsonXContent that contains the deprecated "discovered_master" field.
+     * As of 2.0, to support inclusive language, "discovered_master" field will be replaced by "discovered_cluster_manager".
+     */
+    public void testParseFromXContentWithDeprecatedDiscoveredMasterField() throws IOException {
+        try (
+            XContentParser parser = JsonXContent.jsonXContent.createParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+                "{\"cluster_name\":\"opensearch-cluster\",\"status\":\"green\",\"timed_out\":false,"
+                    + "\"number_of_nodes\":6,\"number_of_data_nodes\":3,\"discovered_cluster_manager\":true,\"discovered_master\":true,"
+                    + "\"active_primary_shards\":4,\"active_shards\":5,\"relocating_shards\":0,\"initializing_shards\":0,"
+                    + "\"unassigned_shards\":0,\"delayed_unassigned_shards\":0,\"number_of_pending_tasks\":0,"
+                    + "\"number_of_in_flight_fetch\":0,\"task_max_waiting_in_queue_millis\":0,"
+                    + "\"active_shards_percent_as_number\":100}"
+            )
+        ) {
+            ClusterHealthResponse clusterHealth = ClusterHealthResponse.fromXContent(parser);
+            assertThat(clusterHealth.hasDiscoveredClusterManager(), Matchers.equalTo(true));
+        }
+
+        try (
+            XContentParser parser = JsonXContent.jsonXContent.createParser(
+                NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+                "{\"cluster_name\":\"opensearch-cluster\",\"status\":\"green\","
+                    + "\"timed_out\":false,\"number_of_nodes\":6,\"number_of_data_nodes\":3,\"discovered_master\":true,"
+                    + "\"active_primary_shards\":4,\"active_shards\":5,\"relocating_shards\":0,\"initializing_shards\":0,"
+                    + "\"unassigned_shards\":0,\"delayed_unassigned_shards\":0,\"number_of_pending_tasks\":0,"
+                    + "\"number_of_in_flight_fetch\":0,\"task_max_waiting_in_queue_millis\":0,"
+                    + "\"active_shards_percent_as_number\":100}"
+            )
+        ) {
+            ClusterHealthResponse clusterHealth = ClusterHealthResponse.fromXContent(parser);
+            assertThat(clusterHealth.hasDiscoveredClusterManager(), Matchers.equalTo(true));
         }
     }
 
@@ -390,7 +453,7 @@ protected ClusterHealthResponse mutateInstance(ClusterHealthResponse instance) {
                     state.getUnassignedShards(),
                     state.getNumberOfNodes(),
                     state.getNumberOfDataNodes(),
-                    state.hasDiscoveredMaster(),
+                    state.hasDiscoveredClusterManager(),
                     state.getActiveShardsPercent(),
                     state.getStatus(),
                     state.getIndices()
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthActionTests.java
index 0b7fe4c8b1dfc..e62dc9b400e13 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/health/TransportClusterHealthActionTests.java
@@ -44,8 +44,8 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodeInfoTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodeInfoTests.java
index 6710276dad0e9..cfd6fcec4bdc6 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodeInfoTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodeInfoTests.java
@@ -71,6 +71,7 @@ public void testGetInfo() {
             null,
             null,
             null,
+            null,
             null
         );
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestTests.java
index 4d7982b063071..412b546e134b7 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/info/NodesInfoRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.cluster.node.info;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashSet;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodeStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodeStatsTests.java
index 380f8ce581e53..e3f16463a5328 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodeStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodeStatsTests.java
@@ -32,15 +32,27 @@
 
 package org.opensearch.action.admin.cluster.node.stats;
 
+import org.opensearch.action.admin.indices.stats.CommonStats;
+import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
+import org.opensearch.action.search.SearchRequestStats;
+import org.opensearch.cluster.coordination.PendingClusterStateStats;
+import org.opensearch.cluster.coordination.PublishClusterStateStats;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.WeightedRoutingStats;
+import org.opensearch.cluster.service.ClusterManagerThrottlingStats;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.AllCircuitBreakerStats;
+import org.opensearch.core.indices.breaker.CircuitBreakerStats;
 import org.opensearch.discovery.DiscoveryStats;
-import org.opensearch.cluster.coordination.PendingClusterStateStats;
-import org.opensearch.cluster.coordination.PublishClusterStateStats;
 import org.opensearch.http.HttpStats;
-import org.opensearch.indices.breaker.AllCircuitBreakerStats;
-import org.opensearch.indices.breaker.CircuitBreakerStats;
+import org.opensearch.index.ReplicationStats;
+import org.opensearch.index.remote.RemoteSegmentStats;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.translog.RemoteTranslogStats;
+import org.opensearch.indices.NodeIndicesStats;
 import org.opensearch.ingest.IngestStats;
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.monitor.jvm.JvmStats;
@@ -73,7 +85,7 @@
 
 public class NodeStatsTests extends OpenSearchTestCase {
     public void testSerialization() throws IOException {
-        NodeStats nodeStats = createNodeStats();
+        NodeStats nodeStats = createNodeStats(true);
         try (BytesStreamOutput out = new BytesStreamOutput()) {
             nodeStats.writeTo(out);
             try (StreamInput in = out.bytes().streamInput()) {
@@ -336,40 +348,31 @@ public void testSerialization() throws IOException {
                 if (ingestStats == null) {
                     assertNull(deserializedIngestStats);
                 } else {
-                    IngestStats.Stats totalStats = ingestStats.getTotalStats();
-                    assertEquals(totalStats.getIngestCount(), deserializedIngestStats.getTotalStats().getIngestCount());
-                    assertEquals(totalStats.getIngestCurrent(), deserializedIngestStats.getTotalStats().getIngestCurrent());
-                    assertEquals(totalStats.getIngestFailedCount(), deserializedIngestStats.getTotalStats().getIngestFailedCount());
-                    assertEquals(totalStats.getIngestTimeInMillis(), deserializedIngestStats.getTotalStats().getIngestTimeInMillis());
+                    OperationStats totalStats = ingestStats.getTotalStats();
+                    assertEquals(totalStats.getCount(), deserializedIngestStats.getTotalStats().getCount());
+                    assertEquals(totalStats.getCurrent(), deserializedIngestStats.getTotalStats().getCurrent());
+                    assertEquals(totalStats.getFailedCount(), deserializedIngestStats.getTotalStats().getFailedCount());
+                    assertEquals(totalStats.getTotalTimeInMillis(), deserializedIngestStats.getTotalStats().getTotalTimeInMillis());
                     assertEquals(ingestStats.getPipelineStats().size(), deserializedIngestStats.getPipelineStats().size());
                     for (IngestStats.PipelineStat pipelineStat : ingestStats.getPipelineStats()) {
                         String pipelineId = pipelineStat.getPipelineId();
-                        IngestStats.Stats deserializedPipelineStats = getPipelineStats(
-                            deserializedIngestStats.getPipelineStats(),
-                            pipelineId
-                        );
-                        assertEquals(pipelineStat.getStats().getIngestFailedCount(), deserializedPipelineStats.getIngestFailedCount());
-                        assertEquals(pipelineStat.getStats().getIngestTimeInMillis(), deserializedPipelineStats.getIngestTimeInMillis());
-                        assertEquals(pipelineStat.getStats().getIngestCurrent(), deserializedPipelineStats.getIngestCurrent());
-                        assertEquals(pipelineStat.getStats().getIngestCount(), deserializedPipelineStats.getIngestCount());
+                        OperationStats deserializedPipelineStats = getPipelineStats(deserializedIngestStats.getPipelineStats(), pipelineId);
+                        assertEquals(pipelineStat.getStats().getFailedCount(), deserializedPipelineStats.getFailedCount());
+                        assertEquals(pipelineStat.getStats().getTotalTimeInMillis(), deserializedPipelineStats.getTotalTimeInMillis());
+                        assertEquals(pipelineStat.getStats().getCurrent(), deserializedPipelineStats.getCurrent());
+                        assertEquals(pipelineStat.getStats().getCount(), deserializedPipelineStats.getCount());
                         List<IngestStats.ProcessorStat> processorStats = ingestStats.getProcessorStats().get(pipelineId);
                         // intentionally validating identical order
                         Iterator<IngestStats.ProcessorStat> it = deserializedIngestStats.getProcessorStats().get(pipelineId).iterator();
                         for (IngestStats.ProcessorStat processorStat : processorStats) {
                             IngestStats.ProcessorStat deserializedProcessorStat = it.next();
+                            assertEquals(processorStat.getStats().getFailedCount(), deserializedProcessorStat.getStats().getFailedCount());
                             assertEquals(
-                                processorStat.getStats().getIngestFailedCount(),
-                                deserializedProcessorStat.getStats().getIngestFailedCount()
-                            );
-                            assertEquals(
-                                processorStat.getStats().getIngestTimeInMillis(),
-                                deserializedProcessorStat.getStats().getIngestTimeInMillis()
-                            );
-                            assertEquals(
-                                processorStat.getStats().getIngestCurrent(),
-                                deserializedProcessorStat.getStats().getIngestCurrent()
+                                processorStat.getStats().getTotalTimeInMillis(),
+                                deserializedProcessorStat.getStats().getTotalTimeInMillis()
                             );
-                            assertEquals(processorStat.getStats().getIngestCount(), deserializedProcessorStat.getStats().getIngestCount());
+                            assertEquals(processorStat.getStats().getCurrent(), deserializedProcessorStat.getStats().getCurrent());
+                            assertEquals(processorStat.getStats().getCount(), deserializedProcessorStat.getStats().getCount());
                         }
                         assertFalse(it.hasNext());
                     }
@@ -418,11 +421,74 @@ public void testSerialization() throws IOException {
                     assertEquals(limited, sum.getCompilationLimitTriggered());
                     assertEquals(compilations, sum.getCompilations());
                 }
+                ClusterManagerThrottlingStats clusterManagerThrottlingStats = nodeStats.getClusterManagerThrottlingStats();
+                ClusterManagerThrottlingStats deserializedClusterManagerThrottlingStats = deserializedNodeStats
+                    .getClusterManagerThrottlingStats();
+                if (clusterManagerThrottlingStats == null) {
+                    assertNull(deserializedClusterManagerThrottlingStats);
+                } else {
+                    assertEquals(
+                        clusterManagerThrottlingStats.getTotalThrottledTaskCount(),
+                        deserializedClusterManagerThrottlingStats.getTotalThrottledTaskCount()
+                    );
+                    assertEquals(
+                        clusterManagerThrottlingStats.getThrottlingCount("test-task"),
+                        deserializedClusterManagerThrottlingStats.getThrottlingCount("test-task")
+                    );
+                }
+
+                WeightedRoutingStats weightedRoutingStats = nodeStats.getWeightedRoutingStats();
+                WeightedRoutingStats deserializedWeightedRoutingStats = deserializedNodeStats.getWeightedRoutingStats();
+                if (weightedRoutingStats == null) {
+                    assertNull(deserializedWeightedRoutingStats);
+                } else {
+                    assertEquals(weightedRoutingStats.getFailOpenCount(), deserializedWeightedRoutingStats.getFailOpenCount());
+
+                }
+
+                NodeIndicesStats nodeIndicesStats = nodeStats.getIndices();
+                NodeIndicesStats deserializedNodeIndicesStats = deserializedNodeStats.getIndices();
+                if (nodeIndicesStats == null) {
+                    assertNull(deserializedNodeIndicesStats);
+                } else {
+                    RemoteSegmentStats remoteSegmentStats = nodeIndicesStats.getSegments().getRemoteSegmentStats();
+                    RemoteSegmentStats deserializedRemoteSegmentStats = deserializedNodeIndicesStats.getSegments().getRemoteSegmentStats();
+                    assertEquals(remoteSegmentStats.getDownloadBytesStarted(), deserializedRemoteSegmentStats.getDownloadBytesStarted());
+                    assertEquals(
+                        remoteSegmentStats.getDownloadBytesSucceeded(),
+                        deserializedRemoteSegmentStats.getDownloadBytesSucceeded()
+                    );
+                    assertEquals(remoteSegmentStats.getDownloadBytesFailed(), deserializedRemoteSegmentStats.getDownloadBytesFailed());
+                    assertEquals(remoteSegmentStats.getUploadBytesStarted(), deserializedRemoteSegmentStats.getUploadBytesStarted());
+                    assertEquals(remoteSegmentStats.getUploadBytesSucceeded(), deserializedRemoteSegmentStats.getUploadBytesSucceeded());
+                    assertEquals(remoteSegmentStats.getUploadBytesFailed(), deserializedRemoteSegmentStats.getUploadBytesFailed());
+                    assertEquals(remoteSegmentStats.getMaxRefreshTimeLag(), deserializedRemoteSegmentStats.getMaxRefreshTimeLag());
+                    assertEquals(remoteSegmentStats.getMaxRefreshBytesLag(), deserializedRemoteSegmentStats.getMaxRefreshBytesLag());
+                    assertEquals(remoteSegmentStats.getTotalRefreshBytesLag(), deserializedRemoteSegmentStats.getTotalRefreshBytesLag());
+                    assertEquals(remoteSegmentStats.getTotalUploadTime(), deserializedRemoteSegmentStats.getTotalUploadTime());
+                    assertEquals(remoteSegmentStats.getTotalDownloadTime(), deserializedRemoteSegmentStats.getTotalDownloadTime());
+
+                    RemoteTranslogStats remoteTranslogStats = nodeIndicesStats.getTranslog().getRemoteTranslogStats();
+                    RemoteTranslogStats deserializedRemoteTranslogStats = deserializedNodeIndicesStats.getTranslog()
+                        .getRemoteTranslogStats();
+                    assertEquals(remoteTranslogStats, deserializedRemoteTranslogStats);
+
+                    ReplicationStats replicationStats = nodeIndicesStats.getSegments().getReplicationStats();
+
+                    ReplicationStats deserializedReplicationStats = deserializedNodeIndicesStats.getSegments().getReplicationStats();
+                    assertEquals(replicationStats.getMaxBytesBehind(), deserializedReplicationStats.getMaxBytesBehind());
+                    assertEquals(replicationStats.getTotalBytesBehind(), deserializedReplicationStats.getTotalBytesBehind());
+                    assertEquals(replicationStats.getMaxReplicationLag(), deserializedReplicationStats.getMaxReplicationLag());
+                }
             }
         }
     }
 
     public static NodeStats createNodeStats() {
+        return createNodeStats(false);
+    }
+
+    public static NodeStats createNodeStats(boolean remoteStoreStats) {
         DiscoveryNode node = new DiscoveryNode(
             "test_node",
             buildNewFakeTransportAddress(),
@@ -537,7 +603,8 @@ public static NodeStats createNodeStats() {
                         randomIntBetween(1, 1000),
                         randomNonNegativeLong(),
                         randomIntBetween(1, 1000),
-                        randomIntBetween(1, 1000)
+                        randomIntBetween(1, 1000),
+                        randomIntBetween(-1, 10)
                     )
                 );
             }
@@ -624,7 +691,7 @@ public static NodeStats createNodeStats() {
             : null;
         IngestStats ingestStats = null;
         if (frequently()) {
-            IngestStats.Stats totalStats = new IngestStats.Stats(
+            OperationStats totalStats = new OperationStats(
                 randomNonNegativeLong(),
                 randomNonNegativeLong(),
                 randomNonNegativeLong(),
@@ -639,7 +706,7 @@ public static NodeStats createNodeStats() {
                 ingestPipelineStats.add(
                     new IngestStats.PipelineStat(
                         pipelineId,
-                        new IngestStats.Stats(
+                        new OperationStats(
                             randomNonNegativeLong(),
                             randomNonNegativeLong(),
                             randomNonNegativeLong(),
@@ -650,7 +717,7 @@ public static NodeStats createNodeStats() {
 
                 List<IngestStats.ProcessorStat> processorPerPipeline = new ArrayList<>(numProcessors);
                 for (int j = 0; j < numProcessors; j++) {
-                    IngestStats.Stats processorStats = new IngestStats.Stats(
+                    OperationStats processorStats = new OperationStats(
                         randomNonNegativeLong(),
                         randomNonNegativeLong(),
                         randomNonNegativeLong(),
@@ -689,12 +756,25 @@ public static NodeStats createNodeStats() {
             }
             adaptiveSelectionStats = new AdaptiveSelectionStats(nodeConnections, nodeStats);
         }
+        ClusterManagerThrottlingStats clusterManagerThrottlingStats = null;
+        if (frequently()) {
+            clusterManagerThrottlingStats = new ClusterManagerThrottlingStats();
+            clusterManagerThrottlingStats.onThrottle("test-task", randomInt());
+        }
         ScriptCacheStats scriptCacheStats = scriptStats != null ? scriptStats.toScriptCacheStats() : null;
-        // TODO NodeIndicesStats are not tested here, way too complicated to create, also they need to be migrated to Writeable yet
+
+        WeightedRoutingStats weightedRoutingStats = null;
+        weightedRoutingStats = WeightedRoutingStats.getInstance();
+        weightedRoutingStats.updateFailOpenCount();
+
+        NodeIndicesStats indicesStats = getNodeIndicesStats(remoteStoreStats);
+
+        // TODO: Only remote_store based aspects of NodeIndicesStats are being tested here.
+        // It is possible to test other metrics in NodeIndicesStats as well since it extends Writeable now
         return new NodeStats(
             node,
             randomNonNegativeLong(),
-            null,
+            indicesStats,
             osStats,
             processStats,
             jvmStats,
@@ -709,11 +789,65 @@ public static NodeStats createNodeStats() {
             adaptiveSelectionStats,
             scriptCacheStats,
             null,
+            null,
+            null,
+            clusterManagerThrottlingStats,
+            weightedRoutingStats,
+            null,
+            null,
             null
         );
     }
 
-    private IngestStats.Stats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
+    private static NodeIndicesStats getNodeIndicesStats(boolean remoteStoreStats) {
+        NodeIndicesStats indicesStats = null;
+        if (remoteStoreStats) {
+            indicesStats = new NodeIndicesStats(new CommonStats(CommonStatsFlags.ALL), new HashMap<>(), new SearchRequestStats());
+            RemoteSegmentStats remoteSegmentStats = indicesStats.getSegments().getRemoteSegmentStats();
+            remoteSegmentStats.addUploadBytesStarted(10L);
+            remoteSegmentStats.addUploadBytesSucceeded(10L);
+            remoteSegmentStats.addUploadBytesFailed(1L);
+            remoteSegmentStats.addDownloadBytesStarted(10L);
+            remoteSegmentStats.addDownloadBytesSucceeded(10L);
+            remoteSegmentStats.addDownloadBytesFailed(1L);
+            remoteSegmentStats.addTotalRefreshBytesLag(5L);
+            remoteSegmentStats.addMaxRefreshBytesLag(2L);
+            remoteSegmentStats.setMaxRefreshTimeLag(2L);
+            remoteSegmentStats.addTotalUploadTime(20L);
+            remoteSegmentStats.addTotalDownloadTime(20L);
+
+            RemoteTranslogStats remoteTranslogStats = indicesStats.getTranslog().getRemoteTranslogStats();
+            RemoteTranslogStats otherRemoteTranslogStats = new RemoteTranslogStats(getRandomRemoteTranslogTransferTrackerStats());
+            remoteTranslogStats.add(otherRemoteTranslogStats);
+        }
+        return indicesStats;
+    }
+
+    private static RemoteTranslogTransferTracker.Stats getRandomRemoteTranslogTransferTrackerStats() {
+        return new RemoteTranslogTransferTracker.Stats(
+            new ShardId("test-idx", "test-idx", randomIntBetween(1, 10)),
+            0L,
+            randomLongBetween(100, 500),
+            randomLongBetween(50, 100),
+            randomLongBetween(100, 200),
+            randomLongBetween(10000, 50000),
+            randomLongBetween(5000, 10000),
+            randomLongBetween(10000, 20000),
+            0L,
+            0D,
+            0D,
+            0D,
+            0L,
+            0L,
+            0L,
+            0L,
+            0D,
+            0D,
+            0D
+        );
+    }
+
+    private OperationStats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
         return pipelineStats.stream().filter(p1 -> p1.getPipelineId().equals(id)).findFirst().map(p2 -> p2.getStats()).orElse(null);
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestTests.java
index f61c3c7676b54..fe9ddf6935948 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/stats/NodesStatsRequestTests.java
@@ -34,8 +34,9 @@
 
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
+
 import java.util.HashSet;
 import java.util.Set;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksTests.java
index d3be6170526fc..6bedcc5ec6feb 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksTests.java
@@ -33,7 +33,8 @@
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
-import org.opensearch.action.ActionListener;
+
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksAction;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
@@ -45,17 +46,19 @@
 import org.opensearch.action.support.replication.ClusterStateCreationUtils;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskCancelledException;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -474,12 +477,12 @@ public void onFailure(Exception e) {
             for (int i = 1; i < testNodes.length; i++) {
                 discoveryNodes[i - 1] = testNodes[i].discoveryNode();
             }
-            DiscoveryNode master = discoveryNodes[0];
+            DiscoveryNode clusterManager = discoveryNodes[0];
             for (int i = 1; i < testNodes.length; i++) {
                 // Notify only nodes that should remain in the cluster
                 setState(
                     testNodes[i].clusterService,
-                    ClusterStateCreationUtils.state(testNodes[i].discoveryNode(), master, discoveryNodes)
+                    ClusterStateCreationUtils.state(testNodes[i].discoveryNode(), clusterManager, discoveryNodes)
                 );
             }
             if (randomBoolean()) {
@@ -563,6 +566,19 @@ public void testNonExistingTaskCancellation() throws Exception {
     public void testCancelConcurrently() throws Exception {
         setupTestNodes(Settings.EMPTY);
         final TaskManager taskManager = testNodes[0].transportService.getTaskManager();
+        AtomicBoolean onTaskCancelled = new AtomicBoolean();
+        AtomicBoolean onTaskCompleted = new AtomicBoolean();
+        taskManager.addTaskEventListeners(new TaskManager.TaskEventListeners() {
+            @Override
+            public void onTaskCancelled(CancellableTask task) {
+                onTaskCancelled.set(true);
+            }
+
+            @Override
+            public void onTaskCompleted(Task task) {
+                onTaskCompleted.set(true);
+            }
+        });
         int numTasks = randomIntBetween(1, 10);
         List<CancellableTask> tasks = new ArrayList<>(numTasks);
         for (int i = 0; i < numTasks; i++) {
@@ -577,11 +593,13 @@ public void testCancelConcurrently() throws Exception {
             threads[i] = new Thread(() -> {
                 phaser.arriveAndAwaitAdvance();
                 taskManager.cancel(cancellingTask, "test", () -> assertTrue(notified.compareAndSet(idx, 0, 1)));
+                assertTrue(onTaskCancelled.get());
             });
             threads[i].start();
         }
         phaser.arriveAndAwaitAdvance();
         taskManager.unregister(cancellingTask);
+        assertTrue(onTaskCompleted.get());
         for (int i = 0; i < threads.length; i++) {
             threads[i].join();
             assertThat(notified.get(i), equalTo(1));
@@ -591,6 +609,21 @@ public void testCancelConcurrently() throws Exception {
         assertTrue(called.get());
     }
 
+    public void testCancelWithCancellationListenerThrowingException() {
+        setupTestNodes(Settings.EMPTY);
+        final TaskManager taskManager = testNodes[0].transportService.getTaskManager();
+        taskManager.addTaskEventListeners(new TaskManager.TaskEventListeners() {
+            @Override
+            public void onTaskCancelled(CancellableTask task) {
+                throw new OpenSearchException("Exception");
+            }
+        });
+        CancellableTask cancellableTask = (CancellableTask) taskManager.register("type-0", "action-0", new CancellableNodeRequest());
+        AtomicBoolean taskCompleted = new AtomicBoolean();
+        assertThrows(OpenSearchException.class, () -> taskManager.cancel(cancellableTask, "test", () -> taskCompleted.set(true)));
+        assertFalse(taskCompleted.get());
+    }
+
     private static void debugDelay(String name) {
         // Introduce an additional pseudo random repeatable race conditions
         String delayName = RandomizedContext.current().getRunnerSeedAsString() + ":" + name;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/RecordingTaskManagerListener.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/RecordingTaskManagerListener.java
index 7756eb12bb3f4..8102059a030a3 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/RecordingTaskManagerListener.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/RecordingTaskManagerListener.java
@@ -34,6 +34,8 @@
 
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.tasks.MockTaskManagerListener;
@@ -41,6 +43,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
 /**
@@ -52,6 +55,7 @@ public class RecordingTaskManagerListener implements MockTaskManagerListener {
     private String localNodeId;
 
     private List<Tuple<Boolean, TaskInfo>> events = new ArrayList<>();
+    private List<Tuple<TaskId, Map<Long, List<ThreadResourceInfo>>>> threadStats = new ArrayList<>();
 
     public RecordingTaskManagerListener(String localNodeId, String... actionMasks) {
         this.actionMasks = actionMasks;
@@ -68,17 +72,26 @@ public synchronized void onTaskRegistered(Task task) {
     @Override
     public synchronized void onTaskUnregistered(Task task) {
         if (Regex.simpleMatch(actionMasks, task.getAction())) {
-            events.add(new Tuple<>(false, task.taskInfo(localNodeId, true)));
+            TaskInfo taskInfo = task.taskInfo(localNodeId, true);
+            events.add(new Tuple<>(false, taskInfo));
+            threadStats.add(new Tuple<>(taskInfo.getTaskId(), task.getResourceStats()));
         }
     }
 
     @Override
     public void waitForTaskCompletion(Task task) {}
 
+    @Override
+    public void taskExecutionStarted(Task task, Boolean closeableInvoked) {}
+
     public synchronized List<Tuple<Boolean, TaskInfo>> getEvents() {
         return Collections.unmodifiableList(new ArrayList<>(events));
     }
 
+    public synchronized List<Tuple<TaskId, Map<Long, List<ThreadResourceInfo>>>> getThreadStats() {
+        return List.copyOf(threadStats);
+    }
+
     public synchronized List<TaskInfo> getRegistrationEvents() {
         List<TaskInfo> events = this.events.stream().filter(Tuple::v1).map(Tuple::v2).collect(Collectors.toList());
         return Collections.unmodifiableList(events);
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/ResourceAwareTasksTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/ResourceAwareTasksTests.java
new file mode 100644
index 0000000000000..9891cde243fbb
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/ResourceAwareTasksTests.java
@@ -0,0 +1,691 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.node.tasks;
+
+import com.sun.management.ThreadMXBean;
+
+import org.apache.lucene.util.Constants;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
+import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
+import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
+import org.opensearch.action.support.ActionTestUtils;
+import org.opensearch.action.support.nodes.BaseNodeRequest;
+import org.opensearch.action.support.nodes.BaseNodesRequest;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.NotifyOnceListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskInfo;
+import org.opensearch.test.tasks.MockTaskManager;
+import org.opensearch.test.tasks.MockTaskManagerListener;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.BiConsumer;
+
+import static org.opensearch.tasks.TaskResourceTrackingService.TASK_ID;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+
+@SuppressForbidden(reason = "ThreadMXBean#getThreadAllocatedBytes")
+public class ResourceAwareTasksTests extends TaskManagerTestCase {
+
+    private static final ThreadMXBean threadMXBean = (ThreadMXBean) ManagementFactory.getThreadMXBean();
+
+    public static class ResourceAwareNodeRequest extends BaseNodeRequest {
+        protected String requestName;
+
+        public ResourceAwareNodeRequest() {
+            super();
+        }
+
+        public ResourceAwareNodeRequest(StreamInput in) throws IOException {
+            super(in);
+            requestName = in.readString();
+        }
+
+        public ResourceAwareNodeRequest(NodesRequest request) {
+            requestName = request.requestName;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(requestName);
+        }
+
+        @Override
+        public String getDescription() {
+            return "ResourceAwareNodeRequest[" + requestName + "]";
+        }
+
+        @Override
+        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+            return new CancellableTask(id, type, action, getDescription(), parentTaskId, headers) {
+                @Override
+                public boolean shouldCancelChildrenOnCancellation() {
+                    return false;
+                }
+
+                @Override
+                public boolean supportsResourceTracking() {
+                    return true;
+                }
+            };
+        }
+    }
+
+    public static class NodesRequest extends BaseNodesRequest<NodesRequest> {
+        private final String requestName;
+
+        private NodesRequest(StreamInput in) throws IOException {
+            super(in);
+            requestName = in.readString();
+        }
+
+        public NodesRequest(String requestName, String... nodesIds) {
+            super(nodesIds);
+            this.requestName = requestName;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(requestName);
+        }
+
+        @Override
+        public String getDescription() {
+            return "NodesRequest[" + requestName + "]";
+        }
+
+        @Override
+        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+            return new CancellableTask(id, type, action, getDescription(), parentTaskId, headers) {
+                @Override
+                public boolean shouldCancelChildrenOnCancellation() {
+                    return true;
+                }
+            };
+        }
+    }
+
+    /**
+     * Simulates a task which executes work on search executor.
+     */
+    class ResourceAwareNodesAction extends AbstractTestNodesAction<NodesRequest, ResourceAwareNodeRequest> {
+        private final TaskTestContext taskTestContext;
+        private final boolean blockForCancellation;
+
+        ResourceAwareNodesAction(
+            String actionName,
+            ThreadPool threadPool,
+            ClusterService clusterService,
+            TransportService transportService,
+            boolean shouldBlock,
+            TaskTestContext taskTestContext
+        ) {
+            super(actionName, threadPool, clusterService, transportService, NodesRequest::new, ResourceAwareNodeRequest::new);
+            this.taskTestContext = taskTestContext;
+            this.blockForCancellation = shouldBlock;
+        }
+
+        @Override
+        protected ResourceAwareNodeRequest newNodeRequest(NodesRequest request) {
+            return new ResourceAwareNodeRequest(request);
+        }
+
+        @Override
+        protected NodeResponse nodeOperation(ResourceAwareNodeRequest request, Task task) {
+            assert task.supportsResourceTracking();
+
+            AtomicLong threadId = new AtomicLong();
+            Future<?> result = threadPool.executor(ThreadPool.Names.SEARCH).submit(new AbstractRunnable() {
+                @Override
+                public void onFailure(Exception e) {
+                    ExceptionsHelper.reThrowIfNotNull(e);
+                }
+
+                @Override
+                @SuppressForbidden(reason = "ThreadMXBean#getThreadAllocatedBytes")
+                protected void doRun() {
+                    taskTestContext.memoryConsumptionWhenExecutionStarts = threadMXBean.getThreadAllocatedBytes(
+                        Thread.currentThread().getId()
+                    );
+                    threadId.set(Thread.currentThread().getId());
+
+                    // operationStartValidator will be called just before the task execution.
+                    if (taskTestContext.operationStartValidator != null) {
+                        taskTestContext.operationStartValidator.accept(task, threadId.get());
+                    }
+
+                    // operationFinishedValidator will be called just after all task threads are marked inactive and
+                    // the task is unregistered.
+                    if (taskTestContext.operationFinishedValidator != null) {
+                        boolean success = task.addResourceTrackingCompletionListener(new NotifyOnceListener<>() {
+                            @Override
+                            protected void innerOnResponse(Task task) {
+                                taskTestContext.operationFinishedValidator.accept(task, threadId.get());
+                            }
+
+                            @Override
+                            protected void innerOnFailure(Exception e) {
+                                ExceptionsHelper.reThrowIfNotNull(e);
+                            }
+                        });
+
+                        if (success == false) {
+                            fail("failed to register a completion listener as task resource tracking has already completed");
+                        }
+                    }
+
+                    Object[] allocation1 = new Object[1000000]; // 4MB
+
+                    if (blockForCancellation) {
+                        // Simulate a job that takes forever to finish
+                        // Using periodic checks method to identify that the task was cancelled
+                        try {
+                            boolean taskCancelled = waitUntil(((CancellableTask) task)::isCancelled);
+                            if (taskCancelled) {
+                                throw new TaskCancelledException("Task Cancelled");
+                            } else {
+                                fail("It should have thrown an exception");
+                            }
+                        } catch (InterruptedException ex) {
+                            Thread.currentThread().interrupt();
+                        }
+
+                    }
+
+                    Object[] allocation2 = new Object[1000000]; // 4MB
+                }
+            });
+
+            try {
+                result.get();
+            } catch (InterruptedException | ExecutionException e) {
+                throw new RuntimeException(e.getCause());
+            }
+
+            return new NodeResponse(clusterService.localNode());
+        }
+
+        @Override
+        protected NodeResponse nodeOperation(ResourceAwareNodeRequest request) {
+            throw new UnsupportedOperationException("the task parameter is required");
+        }
+    }
+
+    private TaskTestContext startResourceAwareNodesAction(
+        TestNode node,
+        boolean blockForCancellation,
+        TaskTestContext taskTestContext,
+        ActionListener<NodesResponse> listener
+    ) {
+        NodesRequest request = new NodesRequest("Test Request", node.getNodeId());
+
+        taskTestContext.requestCompleteLatch = new CountDownLatch(1);
+
+        ResourceAwareNodesAction action = new ResourceAwareNodesAction(
+            "internal:resourceAction",
+            threadPool,
+            node.clusterService,
+            node.transportService,
+            blockForCancellation,
+            taskTestContext
+        );
+        taskTestContext.mainTask = action.execute(request, listener);
+        return taskTestContext;
+    }
+
+    private static class TaskTestContext {
+        private Task mainTask;
+        private CountDownLatch requestCompleteLatch;
+        private BiConsumer<Task, Long> operationStartValidator;
+        private BiConsumer<Task, Long> operationFinishedValidator;
+        private long memoryConsumptionWhenExecutionStarts;
+    }
+
+    public void testBasicTaskResourceTracking() throws Exception {
+        setup(true, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> {
+            // One thread is currently working on task but not finished
+            assertEquals(1, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertTrue(task.getResourceStats().get(threadId).get(0).isActive());
+            assertEquals(0, task.getTotalResourceStats().getCpuTimeInNanos());
+            assertEquals(0, task.getTotalResourceStats().getMemoryInBytes());
+            assertEquals(0, task.getAverageResourceStats().getMemoryInBytes());
+            assertEquals(0, task.getAverageResourceStats().getCpuTimeInNanos());
+            assertEquals(0, task.getMinResourceStats().getMemoryInBytes());
+            assertEquals(0, task.getMinResourceStats().getCpuTimeInNanos());
+            assertEquals(0, task.getMaxResourceStats().getMemoryInBytes());
+            assertEquals(0, task.getMaxResourceStats().getCpuTimeInNanos());
+            assertEquals(1, task.getThreadUsage().getThreadExecutions());
+            assertEquals(1, task.getThreadUsage().getActiveThreads());
+        };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> {
+            // Thread has finished working on the task's runnable
+            assertEquals(0, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertFalse(task.getResourceStats().get(threadId).get(0).isActive());
+            assertEquals(1, task.getThreadUsage().getThreadExecutions());
+            assertEquals(0, task.getThreadUsage().getActiveThreads());
+
+            long expectedArrayAllocationOverhead = 2 * 4000000; // Task's memory overhead due to array allocations
+            long actualTaskMemoryOverhead = task.getTotalResourceStats().getMemoryInBytes();
+
+            assertMemoryUsageWithinLimits(
+                actualTaskMemoryOverhead - taskTestContext.memoryConsumptionWhenExecutionStarts,
+                expectedArrayAllocationOverhead
+            );
+            assertCPUTime(task.getTotalResourceStats().getCpuTimeInNanos());
+            // In basic single threaded case min == max == average == total
+            assertEquals(task.getTotalResourceStats().getCpuTimeInNanos(), task.getAverageResourceStats().getCpuTimeInNanos());
+            assertEquals(task.getTotalResourceStats().getCpuTimeInNanos(), task.getMinResourceStats().getCpuTimeInNanos());
+            assertEquals(task.getTotalResourceStats().getCpuTimeInNanos(), task.getMaxResourceStats().getCpuTimeInNanos());
+            assertEquals(task.getTotalResourceStats().getMemoryInBytes(), task.getAverageResourceStats().getMemoryInBytes());
+            assertEquals(task.getTotalResourceStats().getMemoryInBytes(), task.getMinResourceStats().getMemoryInBytes());
+            assertEquals(task.getTotalResourceStats().getMemoryInBytes(), task.getMaxResourceStats().getMemoryInBytes());
+        };
+
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertTasksRequestFinishedSuccessfully(responseReference.get(), throwableReference.get());
+    }
+
+    public void testTaskResourceTrackingDuringTaskCancellation() throws Exception {
+        setup(true, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> {
+            // One thread is currently working on task but not finished
+            assertEquals(1, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertTrue(task.getResourceStats().get(threadId).get(0).isActive());
+            assertEquals(0, task.getTotalResourceStats().getCpuTimeInNanos());
+            assertEquals(0, task.getTotalResourceStats().getMemoryInBytes());
+        };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> {
+            // Thread has finished working on the task's runnable
+            assertEquals(0, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertFalse(task.getResourceStats().get(threadId).get(0).isActive());
+
+            // allocations are completed before the task is cancelled
+            long expectedArrayAllocationOverhead = 4000000; // Task's memory overhead due to array allocations
+            long taskCancellationOverhead = 30000; // Task cancellation overhead ~ 30Kb
+            long actualTaskMemoryOverhead = task.getTotalResourceStats().getMemoryInBytes();
+
+            long expectedOverhead = expectedArrayAllocationOverhead + taskCancellationOverhead;
+            assertMemoryUsageWithinLimits(
+                actualTaskMemoryOverhead - taskTestContext.memoryConsumptionWhenExecutionStarts,
+                expectedOverhead
+            );
+            assertCPUTime(task.getTotalResourceStats().getCpuTimeInNanos());
+        };
+
+        startResourceAwareNodesAction(testNodes[0], true, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Cancel main task
+        CancelTasksRequest request = new CancelTasksRequest();
+        request.setReason("Cancelling request to verify Task resource tracking behaviour");
+        request.setTaskId(new TaskId(testNodes[0].getNodeId(), taskTestContext.mainTask.getId()));
+        ActionTestUtils.executeBlocking(testNodes[0].transportCancelTasksAction, request);
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertEquals(0, resourceTasks.size());
+        assertNull(throwableReference.get());
+        assertNotNull(responseReference.get());
+        assertEquals(1, responseReference.get().failureCount());
+        assertEquals(TaskCancelledException.class, findActualException(responseReference.get().failures().get(0)).getClass());
+    }
+
+    public void testTaskResourceTrackingDisabled() throws Exception {
+        setup(false, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> { assertEquals(0, resourceTasks.size()); };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> { assertEquals(0, resourceTasks.size()); };
+
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertTasksRequestFinishedSuccessfully(responseReference.get(), throwableReference.get());
+    }
+
+    public void testTaskResourceTrackingDisabledWhileTaskInProgress() throws Exception {
+        setup(true, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> {
+            // One thread is currently working on task but not finished
+            assertEquals(1, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertTrue(task.getResourceStats().get(threadId).get(0).isActive());
+            assertEquals(0, task.getTotalResourceStats().getCpuTimeInNanos());
+            assertEquals(0, task.getTotalResourceStats().getMemoryInBytes());
+
+            testNodes[0].taskResourceTrackingService.setTaskResourceTrackingEnabled(false);
+        };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> {
+            // Thread has finished working on the task's runnable
+            assertEquals(0, resourceTasks.size());
+            assertEquals(1, task.getResourceStats().size());
+            assertEquals(1, task.getResourceStats().get(threadId).size());
+            assertFalse(task.getResourceStats().get(threadId).get(0).isActive());
+
+            long expectedArrayAllocationOverhead = 2 * 4000000; // Task's memory overhead due to array allocations
+            long actualTaskMemoryOverhead = task.getTotalResourceStats().getMemoryInBytes();
+
+            assertMemoryUsageWithinLimits(
+                actualTaskMemoryOverhead - taskTestContext.memoryConsumptionWhenExecutionStarts,
+                expectedArrayAllocationOverhead
+            );
+            assertCPUTime(task.getTotalResourceStats().getCpuTimeInNanos());
+        };
+
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertTasksRequestFinishedSuccessfully(responseReference.get(), throwableReference.get());
+    }
+
+    public void testTaskResourceTrackingEnabledWhileTaskInProgress() throws Exception {
+        setup(false, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> {
+            assertEquals(0, resourceTasks.size());
+
+            testNodes[0].taskResourceTrackingService.setTaskResourceTrackingEnabled(true);
+        };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> { assertEquals(0, resourceTasks.size()); };
+
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertTasksRequestFinishedSuccessfully(responseReference.get(), throwableReference.get());
+    }
+
+    public void testOnDemandRefreshWhileFetchingTasks() throws InterruptedException {
+        setup(true, false);
+
+        final AtomicReference<Throwable> throwableReference = new AtomicReference<>();
+        final AtomicReference<NodesResponse> responseReference = new AtomicReference<>();
+
+        TaskTestContext taskTestContext = new TaskTestContext();
+
+        Map<Long, Task> resourceTasks = testNodes[0].taskResourceTrackingService.getResourceAwareTasks();
+
+        taskTestContext.operationStartValidator = (task, threadId) -> {
+            ListTasksResponse listTasksResponse = ActionTestUtils.executeBlocking(
+                testNodes[0].transportListTasksAction,
+                new ListTasksRequest().setActions("internal:resourceAction*").setDetailed(true)
+            );
+
+            TaskInfo taskInfo = listTasksResponse.getTasks().get(1);
+
+            assertNotNull(taskInfo.getResourceStats());
+            assertNotNull(taskInfo.getResourceStats().getResourceUsageInfo());
+            assertTrue(taskInfo.getResourceStats().getResourceUsageInfo().get("total") instanceof TaskResourceUsage);
+            TaskResourceUsage taskResourceUsage = (TaskResourceUsage) taskInfo.getResourceStats().getResourceUsageInfo().get("total");
+            assertCPUTime(taskResourceUsage.getCpuTimeInNanos());
+            assertTrue(taskResourceUsage.getMemoryInBytes() > 0);
+        };
+
+        taskTestContext.operationFinishedValidator = (task, threadId) -> { assertEquals(0, resourceTasks.size()); };
+
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                responseReference.set(listTasksResponse);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throwableReference.set(e);
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        // Waiting for whole request to complete and return successfully till client
+        taskTestContext.requestCompleteLatch.await();
+
+        assertTasksRequestFinishedSuccessfully(responseReference.get(), throwableReference.get());
+    }
+
+    public void testTaskIdPersistsInThreadContext() throws InterruptedException {
+        setup(true, true);
+
+        final List<Long> taskIdsAddedToThreadContext = new ArrayList<>();
+        final List<Long> taskIdsRemovedFromThreadContext = new ArrayList<>();
+        AtomicLong actualTaskIdInThreadContext = new AtomicLong(-1);
+        AtomicLong expectedTaskIdInThreadContext = new AtomicLong(-2);
+
+        ((MockTaskManager) testNodes[0].transportService.getTaskManager()).addListener(new MockTaskManagerListener() {
+            @Override
+            public void waitForTaskCompletion(Task task) {}
+
+            @Override
+            public void taskExecutionStarted(Task task, Boolean closeableInvoked) {
+                if (closeableInvoked) {
+                    taskIdsRemovedFromThreadContext.add(task.getId());
+                } else {
+                    taskIdsAddedToThreadContext.add(task.getId());
+                }
+            }
+
+            @Override
+            public void onTaskRegistered(Task task) {}
+
+            @Override
+            public void onTaskUnregistered(Task task) {
+                if (task.getAction().equals("internal:resourceAction[n]")) {
+                    expectedTaskIdInThreadContext.set(task.getId());
+                    actualTaskIdInThreadContext.set(threadPool.getThreadContext().getTransient(TASK_ID));
+                }
+            }
+        });
+
+        TaskTestContext taskTestContext = new TaskTestContext();
+        startResourceAwareNodesAction(testNodes[0], false, taskTestContext, new ActionListener<NodesResponse>() {
+            @Override
+            public void onResponse(NodesResponse listTasksResponse) {
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                taskTestContext.requestCompleteLatch.countDown();
+            }
+        });
+
+        taskTestContext.requestCompleteLatch.await();
+
+        // It is possible for the MockTaskManagerListener to be called after the response is sent already.
+        // Wait enough time for taskId to be added to taskIdsRemovedFromThreadContext before performing validations.
+        waitUntil(() -> taskIdsAddedToThreadContext.size() == taskIdsRemovedFromThreadContext.size(), 5, TimeUnit.SECONDS);
+
+        assertEquals(expectedTaskIdInThreadContext.get(), actualTaskIdInThreadContext.get());
+        assertThat(taskIdsAddedToThreadContext, containsInAnyOrder(taskIdsRemovedFromThreadContext.toArray()));
+    }
+
+    private void setup(boolean resourceTrackingEnabled, boolean useMockTaskManager) {
+        Settings settings = Settings.builder()
+            .put("task_resource_tracking.enabled", resourceTrackingEnabled)
+            .put(MockTaskManager.USE_MOCK_TASK_MANAGER_SETTING.getKey(), useMockTaskManager)
+            .build();
+        setupTestNodes(settings);
+        connectNodes(testNodes[0]);
+
+        runnableTaskListener.set(testNodes[0].taskResourceTrackingService);
+    }
+
+    private Throwable findActualException(Exception e) {
+        Throwable throwable = e.getCause();
+        while (throwable.getCause() != null) {
+            throwable = throwable.getCause();
+        }
+        return throwable;
+    }
+
+    private void assertTasksRequestFinishedSuccessfully(NodesResponse nodesResponse, Throwable throwable) {
+        assertNull(throwable);
+        assertNotNull(nodesResponse);
+        assertEquals(0, nodesResponse.failureCount());
+    }
+
+    private void assertMemoryUsageWithinLimits(long actual, long expected) {
+        // 5% buffer up to 500 KB to account for classloading overhead.
+        long maxOverhead = Math.min(500000, expected * 5 / 100);
+        assertThat(actual, lessThanOrEqualTo(expected + maxOverhead));
+    }
+
+    private void assertCPUTime(long cpuTimeInNanos) {
+        // Windows registers a cpu tick at a default of ~15ms which is slightly slower than other OSs.
+        // The work done within the runnable in this test often completes in under that time and returns a 0 value from
+        // ThreadMXBean.getThreadCpuTime. To reduce flakiness in this test accept 0 as a value on Windows.
+        if (Constants.WINDOWS) {
+            assertTrue("Cpu should be non negative on windows", cpuTimeInNanos >= 0);
+        } else {
+            assertTrue("Cpu should have a positive value", cpuTimeInNanos > 0);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
index c8411b31e0709..8ee41e43a5bed 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.TransportCancelTasksAction;
@@ -47,20 +46,25 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.tasks.TaskCancellationService;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.tasks.TaskResourceTrackingService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.tasks.MockTaskManager;
+import org.opensearch.threadpool.RunnableTaskExecutionListener;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -74,6 +78,7 @@
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 
 import static java.util.Collections.emptyMap;
@@ -89,10 +94,12 @@ public abstract class TaskManagerTestCase extends OpenSearchTestCase {
     protected ThreadPool threadPool;
     protected TestNode[] testNodes;
     protected int nodesCount;
+    protected AtomicReference<RunnableTaskExecutionListener> runnableTaskListener;
 
     @Before
     public void setupThreadPool() {
-        threadPool = new TestThreadPool(TransportTasksActionTests.class.getSimpleName());
+        runnableTaskListener = new AtomicReference<>();
+        threadPool = new TestThreadPool(TransportTasksActionTests.class.getSimpleName(), runnableTaskListener);
     }
 
     public void setupTestNodes(Settings settings) {
@@ -204,20 +211,27 @@ public TestNode(String name, ThreadPool threadPool, Settings settings) {
                     new NetworkService(Collections.emptyList()),
                     PageCacheRecycler.NON_RECYCLING_INSTANCE,
                     new NamedWriteableRegistry(ClusterModule.getNamedWriteables()),
-                    new NoneCircuitBreakerService()
+                    new NoneCircuitBreakerService(),
+                    NoopTracer.INSTANCE
                 ),
                 threadPool,
                 TransportService.NOOP_TRANSPORT_INTERCEPTOR,
                 boundTransportAddressDiscoveryNodeFunction,
                 null,
-                Collections.emptySet()
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
             ) {
                 @Override
-                protected TaskManager createTaskManager(Settings settings, ThreadPool threadPool, Set<String> taskHeaders) {
+                protected TaskManager createTaskManager(
+                    Settings settings,
+                    ClusterSettings clusterSettings,
+                    ThreadPool threadPool,
+                    Set<String> taskHeaders
+                ) {
                     if (MockTaskManager.USE_MOCK_TASK_MANAGER_SETTING.get(settings)) {
                         return new MockTaskManager(settings, threadPool, taskHeaders);
                     } else {
-                        return super.createTaskManager(settings, threadPool, taskHeaders);
+                        return super.createTaskManager(settings, clusterSettings, threadPool, taskHeaders);
                     }
                 }
             };
@@ -225,14 +239,22 @@ protected TaskManager createTaskManager(Settings settings, ThreadPool threadPool
             transportService.start();
             clusterService = createClusterService(threadPool, discoveryNode.get());
             clusterService.addStateApplier(transportService.getTaskManager());
+            taskResourceTrackingService = new TaskResourceTrackingService(settings, clusterService.getClusterSettings(), threadPool);
+            transportService.getTaskManager().setTaskResourceTrackingService(taskResourceTrackingService);
             ActionFilters actionFilters = new ActionFilters(emptySet());
-            transportListTasksAction = new TransportListTasksAction(clusterService, transportService, actionFilters);
+            transportListTasksAction = new TransportListTasksAction(
+                clusterService,
+                transportService,
+                actionFilters,
+                taskResourceTrackingService
+            );
             transportCancelTasksAction = new TransportCancelTasksAction(clusterService, transportService, actionFilters);
             transportService.acceptIncomingRequests();
         }
 
         public final ClusterService clusterService;
         public final TransportService transportService;
+        public final TaskResourceTrackingService taskResourceTrackingService;
         private final SetOnce<DiscoveryNode> discoveryNode = new SetOnce<>();
         public final TransportListTasksAction transportListTasksAction;
         public final TransportCancelTasksAction transportCancelTasksAction;
@@ -257,9 +279,9 @@ public static void connectNodes(TestNode... nodes) {
         for (int i = 0; i < nodes.length; i++) {
             discoveryNodes[i] = nodes[i].discoveryNode();
         }
-        DiscoveryNode master = discoveryNodes[0];
+        DiscoveryNode clusterManager = discoveryNodes[0];
         for (TestNode node : nodes) {
-            setState(node.clusterService, ClusterStateCreationUtils.state(node.discoveryNode(), master, discoveryNodes));
+            setState(node.clusterService, ClusterStateCreationUtils.state(node.discoveryNode(), clusterManager, discoveryNodes));
         }
         for (TestNode nodeA : nodes) {
             for (TestNode nodeB : nodes) {
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskTests.java
index 5f8d5992c9f2f..34387b0fc7b7d 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskTests.java
@@ -31,9 +31,14 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.action.search.SearchAction;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.core.tasks.resourcetracker.ResourceStatsType;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageMetric;
+import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -41,6 +46,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import static org.opensearch.tasks.TaskInfoTests.randomResourceStats;
+
 public class TaskTests extends OpenSearchTestCase {
 
     public void testTaskInfoToString() {
@@ -61,7 +68,8 @@ public void testTaskInfoToString() {
             cancellable,
             cancelled,
             TaskId.EMPTY_TASK_ID,
-            Collections.singletonMap("foo", "bar")
+            Collections.singletonMap("foo", "bar"),
+            randomResourceStats(randomBoolean())
         );
         String taskInfoString = taskInfo.toString();
         Map<String, Object> map = XContentHelper.convertToMap(new BytesArray(taskInfoString.getBytes(StandardCharsets.UTF_8)), true).v2();
@@ -81,6 +89,7 @@ public void testCancellableOptionWhenCancelledTrue() {
         long taskId = randomIntBetween(0, 100000);
         long startTime = randomNonNegativeLong();
         long runningTime = randomNonNegativeLong();
+        long cancellationStartTime = randomNonNegativeLong();
         boolean cancellable = true;
         boolean cancelled = true;
         TaskInfo taskInfo = new TaskInfo(
@@ -94,12 +103,15 @@ public void testCancellableOptionWhenCancelledTrue() {
             cancellable,
             cancelled,
             TaskId.EMPTY_TASK_ID,
-            Collections.singletonMap("foo", "bar")
+            Collections.singletonMap("foo", "bar"),
+            randomResourceStats(randomBoolean()),
+            cancellationStartTime
         );
         String taskInfoString = taskInfo.toString();
         Map<String, Object> map = XContentHelper.convertToMap(new BytesArray(taskInfoString.getBytes(StandardCharsets.UTF_8)), true).v2();
         assertEquals(map.get("cancellable"), cancellable);
         assertEquals(map.get("cancelled"), cancelled);
+        assertEquals(map.get("cancellation_time_millis"), cancellationStartTime);
     }
 
     public void testCancellableOptionWhenCancelledFalse() {
@@ -120,7 +132,8 @@ public void testCancellableOptionWhenCancelledFalse() {
             cancellable,
             cancelled,
             TaskId.EMPTY_TASK_ID,
-            Collections.singletonMap("foo", "bar")
+            Collections.singletonMap("foo", "bar"),
+            randomResourceStats(randomBoolean())
         );
         String taskInfoString = taskInfo.toString();
         Map<String, Object> map = XContentHelper.convertToMap(new BytesArray(taskInfoString.getBytes(StandardCharsets.UTF_8)), true).v2();
@@ -148,9 +161,79 @@ public void testNonCancellableOption() {
                 cancellable,
                 cancelled,
                 TaskId.EMPTY_TASK_ID,
-                Collections.singletonMap("foo", "bar")
+                Collections.singletonMap("foo", "bar"),
+                randomResourceStats(randomBoolean())
             )
         );
         assertEquals(e.getMessage(), "task cannot be cancelled");
     }
+
+    public void testTaskResourceStats() {
+        final Task task = new Task(
+            randomLong(),
+            "transport",
+            SearchAction.NAME,
+            "description",
+            new TaskId(randomLong() + ":" + randomLong()),
+            Collections.emptyMap()
+        );
+
+        long totalMemory = 0L;
+        long totalCPU = 0L;
+
+        // reporting resource consumption events and checking total consumption values
+        for (int i = 0; i < randomIntBetween(2, 10); i++) {
+            long initial_memory = randomLongBetween(1, 100);
+            long initial_cpu = randomLongBetween(1, 100);
+
+            ResourceUsageMetric[] initialTaskResourceMetrics = new ResourceUsageMetric[] {
+                new ResourceUsageMetric(ResourceStats.MEMORY, initial_memory),
+                new ResourceUsageMetric(ResourceStats.CPU, initial_cpu) };
+            task.startThreadResourceTracking(i, ResourceStatsType.WORKER_STATS, initialTaskResourceMetrics);
+
+            long memory = initial_memory + randomLongBetween(1, 10000);
+            long cpu = initial_cpu + randomLongBetween(1, 10000);
+
+            totalMemory += memory - initial_memory;
+            totalCPU += cpu - initial_cpu;
+
+            ResourceUsageMetric[] taskResourceMetrics = new ResourceUsageMetric[] {
+                new ResourceUsageMetric(ResourceStats.MEMORY, memory),
+                new ResourceUsageMetric(ResourceStats.CPU, cpu) };
+            task.updateThreadResourceStats(i, ResourceStatsType.WORKER_STATS, taskResourceMetrics);
+            task.stopThreadResourceTracking(i, ResourceStatsType.WORKER_STATS);
+        }
+        assertEquals(task.getTotalResourceStats().getMemoryInBytes(), totalMemory);
+        assertEquals(task.getTotalResourceStats().getCpuTimeInNanos(), totalCPU);
+        // Basic sanity testing that min < average < max < total
+        assertTrue(task.getMinResourceStats().getMemoryInBytes() < task.getAverageResourceStats().getMemoryInBytes());
+        assertTrue(task.getAverageResourceStats().getMemoryInBytes() < task.getMaxResourceStats().getMemoryInBytes());
+        assertTrue(task.getMaxResourceStats().getMemoryInBytes() < task.getTotalResourceStats().getMemoryInBytes());
+
+        // updating should throw an IllegalStateException when active entry is not present.
+        try {
+            task.updateThreadResourceStats(randomInt(), ResourceStatsType.WORKER_STATS);
+            fail("update should not be successful as active entry is not present!");
+        } catch (IllegalStateException e) {
+            // pass
+        }
+
+        // re-adding a thread entry that is already present, should throw an exception
+        int threadId = randomInt();
+        task.startThreadResourceTracking(threadId, ResourceStatsType.WORKER_STATS, new ResourceUsageMetric(ResourceStats.MEMORY, 100));
+        try {
+            task.startThreadResourceTracking(threadId, ResourceStatsType.WORKER_STATS);
+            fail("add/start should not be successful as active entry is already present!");
+        } catch (IllegalStateException e) {
+            // pass
+        }
+
+        // existing active entry is present only for memory, update cannot be called with cpu values.
+        try {
+            task.updateThreadResourceStats(threadId, ResourceStatsType.WORKER_STATS, new ResourceUsageMetric(ResourceStats.CPU, 200));
+            fail("update should not be successful as entry for CPU is not present!");
+        } catch (IllegalStateException e) {
+            // pass
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TestTaskPlugin.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TestTaskPlugin.java
index 3bb1957c69fb4..73067cba22b9a 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TestTaskPlugin.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TestTaskPlugin.java
@@ -32,13 +32,11 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestBuilder;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.IndicesRequest;
-import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.ActionType;
+import org.opensearch.action.FailedNodeException;
+import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.nodes.BaseNodeRequest;
@@ -54,28 +52,30 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.ActionPlugin;
-import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.NetworkPlugin;
+import org.opensearch.plugins.Plugin;
 import org.opensearch.tasks.CancellableTask;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportService;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
index 7590bf88eeca0..e99207891beee 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
@@ -31,8 +31,6 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
@@ -51,19 +49,20 @@
 import org.opensearch.action.support.tasks.TransportTasksAction;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskInfo;
 import org.opensearch.test.tasks.MockTaskManager;
 import org.opensearch.threadpool.ThreadPool;
@@ -343,7 +342,7 @@ public void onFailure(Exception e) {
             "local tasks [{}]",
             localTasks.values()
                 .stream()
-                .map(t -> Strings.toString(t.taskInfo(testNodes[0].getNodeId(), true)))
+                .map(t -> Strings.toString(MediaTypeRegistry.JSON, t.taskInfo(testNodes[0].getNodeId(), true)))
                 .collect(Collectors.joining(","))
         );
         assertEquals(2, localTasks.size()); // all node tasks + 1 coordinating task
@@ -761,7 +760,7 @@ public void testTasksToXContentGrouping() throws Exception {
     }
 
     private Map<String, Object> serialize(ListTasksResponse response, boolean byParents) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
         builder.startObject();
         if (byParents) {
             DiscoveryNodes nodes = testNodes[0].clusterService.state().nodes();
@@ -771,7 +770,7 @@ private Map<String, Object> serialize(ListTasksResponse response, boolean byPare
         }
         builder.endObject();
         builder.flush();
-        logger.info(Strings.toString(builder));
+        logger.info(builder.toString());
         return XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType()).v2();
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestTests.java
index 4c8f525541681..8a6cc2a8cc396 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/cancel/CancelTasksRequestTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.node.tasks.cancel;
 
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequestTests.java
new file mode 100644
index 0000000000000..7fff55f1d1259
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreRequestTests.java
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class RestoreRemoteStoreRequestTests extends AbstractWireSerializingTestCase<RestoreRemoteStoreRequest> {
+    private RestoreRemoteStoreRequest randomState(RestoreRemoteStoreRequest instance) {
+        if (randomBoolean()) {
+            List<String> indices = new ArrayList<>();
+            int count = randomInt(3) + 1;
+
+            for (int i = 0; i < count; ++i) {
+                indices.add(randomAlphaOfLength(randomInt(3) + 2));
+            }
+
+            instance.indices(indices);
+        }
+
+        instance.waitForCompletion(randomBoolean());
+        instance.restoreAllShards(randomBoolean());
+
+        if (randomBoolean()) {
+            instance.masterNodeTimeout(randomTimeValue());
+        }
+
+        return instance;
+    }
+
+    @Override
+    protected RestoreRemoteStoreRequest createTestInstance() {
+        return randomState(new RestoreRemoteStoreRequest());
+    }
+
+    @Override
+    protected Writeable.Reader<RestoreRemoteStoreRequest> instanceReader() {
+        return RestoreRemoteStoreRequest::new;
+    }
+
+    @Override
+    protected RestoreRemoteStoreRequest mutateInstance(RestoreRemoteStoreRequest instance) throws IOException {
+        RestoreRemoteStoreRequest copy = copyInstance(instance);
+        // ensure that at least one property is different
+        List<String> indices = new ArrayList<>(List.of(instance.indices()));
+        indices.add("copied");
+        copy.indices(indices);
+        return randomState(copy);
+    }
+
+    public void testSource() throws IOException {
+        RestoreRemoteStoreRequest original = createTestInstance();
+        XContentBuilder builder = original.toXContent(XContentFactory.jsonBuilder(), new ToXContent.MapParams(Collections.emptyMap()));
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
+            .createParser(NamedXContentRegistry.EMPTY, null, BytesReference.bytes(builder).streamInput());
+        Map<String, Object> map = parser.mapOrdered();
+
+        RestoreRemoteStoreRequest processed = new RestoreRemoteStoreRequest();
+        processed.masterNodeTimeout(original.masterNodeTimeout());
+        processed.waitForCompletion(original.waitForCompletion());
+        processed.restoreAllShards(original.restoreAllShards());
+        processed.source(map);
+
+        assertEquals(original, processed);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponseTests.java
new file mode 100644
index 0000000000000..995d20af3e339
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/restore/RestoreRemoteStoreResponseTests.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.restore;
+
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.snapshots.RestoreInfo;
+import org.opensearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+public class RestoreRemoteStoreResponseTests extends AbstractXContentTestCase<RestoreRemoteStoreResponse> {
+
+    @Override
+    protected RestoreRemoteStoreResponse createTestInstance() {
+        if (randomBoolean()) {
+            String name = "remote_store";
+            List<String> indices = new ArrayList<>();
+            indices.add("test0");
+            indices.add("test1");
+            int totalShards = randomIntBetween(1, 1000);
+            int successfulShards = randomIntBetween(0, totalShards);
+            return new RestoreRemoteStoreResponse(new RestoreInfo(name, indices, totalShards, successfulShards));
+        } else {
+            return new RestoreRemoteStoreResponse((RestoreInfo) null);
+        }
+    }
+
+    @Override
+    protected RestoreRemoteStoreResponse doParseInstance(XContentParser parser) throws IOException {
+        return RestoreRemoteStoreResponse.fromXContent(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return true;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestTests.java
new file mode 100644
index 0000000000000..8a32f36e8fd10
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsRequestTests.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class RemoteStoreStatsRequestTests extends OpenSearchTestCase {
+
+    public void testAddIndexName() throws Exception {
+        RemoteStoreStatsRequest request = new RemoteStoreStatsRequest();
+        request.indices("random-index-name");
+        RemoteStoreStatsRequest deserializedRequest = roundTripRequest(request);
+        assertRequestsEqual(request, deserializedRequest);
+    }
+
+    public void testAddShardId() throws Exception {
+        RemoteStoreStatsRequest request = new RemoteStoreStatsRequest();
+        request.indices("random-index-name");
+        request.shards("0");
+        RemoteStoreStatsRequest deserializedRequest = roundTripRequest(request);
+        assertRequestsEqual(request, deserializedRequest);
+    }
+
+    public void testAddLocalShardsOnly() throws Exception {
+        RemoteStoreStatsRequest request = new RemoteStoreStatsRequest();
+        request.indices("random-index-name");
+        request.local(true);
+        RemoteStoreStatsRequest deserializedRequest = roundTripRequest(request);
+        assertRequestsEqual(request, deserializedRequest);
+    }
+
+    public void testAddShardIdAndLocalShardsOnly() throws Exception {
+        RemoteStoreStatsRequest request = new RemoteStoreStatsRequest();
+        request.indices("random-index-name");
+        request.shards("0");
+        request.local(true);
+        RemoteStoreStatsRequest deserializedRequest = roundTripRequest(request);
+        assertRequestsEqual(request, deserializedRequest);
+    }
+
+    /**
+     * Serialize and deserialize a request.
+     * @param request A request to serialize.
+     * @return The deserialized, "round-tripped" request.
+     */
+    private static RemoteStoreStatsRequest roundTripRequest(RemoteStoreStatsRequest request) throws Exception {
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                return new RemoteStoreStatsRequest(in);
+            }
+        }
+    }
+
+    private static void assertRequestsEqual(RemoteStoreStatsRequest request1, RemoteStoreStatsRequest request2) {
+        assertThat(request1.indices(), equalTo(request2.indices()));
+        assertThat(request1.shards(), equalTo(request2.shards()));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponseTests.java
new file mode 100644
index 0000000000000..8cc0982c86233
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsResponseTests.java
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.Map;
+
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.compareStatsResponse;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createEmptyTranslogStats;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createShardRouting;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForNewPrimary;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForNewReplica;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForRemoteStoreRestoredPrimary;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createTranslogStats;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
+
+public class RemoteStoreStatsResponseTests extends OpenSearchTestCase {
+    private ThreadPool threadPool;
+    private ShardId shardId;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("remote_store_stats_test");
+        shardId = new ShardId("index", "uuid", 0);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testSerializationForPrimary() throws Exception {
+        RemoteSegmentTransferTracker.Stats mockSegmentTrackerStats = createStatsForNewPrimary(shardId);
+        RemoteTranslogTransferTracker.Stats mockTranslogTrackerStats = createTranslogStats(shardId);
+        ShardRouting primaryShardRouting = createShardRouting(shardId, true);
+        RemoteStoreStats primaryShardStats = new RemoteStoreStats(mockSegmentTrackerStats, mockTranslogTrackerStats, primaryShardRouting);
+        RemoteStoreStatsResponse statsResponse = new RemoteStoreStatsResponse(
+            new RemoteStoreStats[] { primaryShardStats },
+            1,
+            1,
+            0,
+            new ArrayList<DefaultShardOperationFailedException>()
+        );
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        statsResponse.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonResponseObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType())
+            .v2();
+        Map<String, Object> metadataShardsObject = (Map<String, Object>) jsonResponseObject.get("_shards");
+        assertEquals(metadataShardsObject.get("total"), 1);
+        assertEquals(metadataShardsObject.get("successful"), 1);
+        assertEquals(metadataShardsObject.get("failed"), 0);
+        Map<String, Object> indicesObject = (Map<String, Object>) jsonResponseObject.get("indices");
+        assertTrue(indicesObject.containsKey("index"));
+        Map<String, Object> shardsObject = (Map) ((Map) indicesObject.get("index")).get("shards");
+        ArrayList<Map<String, Object>> perShardNumberObject = (ArrayList<Map<String, Object>>) shardsObject.get("0");
+        assertEquals(perShardNumberObject.size(), 1);
+        Map<String, Object> perShardCopyObject = perShardNumberObject.get(0);
+        compareStatsResponse(perShardCopyObject, mockSegmentTrackerStats, mockTranslogTrackerStats, primaryShardRouting);
+    }
+
+    public void testSerializationForBothPrimaryAndReplica() throws Exception {
+        RemoteSegmentTransferTracker.Stats mockPrimarySegmentTrackerStats = createStatsForNewPrimary(shardId);
+        RemoteSegmentTransferTracker.Stats mockReplicaSegmentTrackerStats = createStatsForNewReplica(shardId);
+        RemoteTranslogTransferTracker.Stats mockPrimaryTranslogTrackerStats = createTranslogStats(shardId);
+        RemoteTranslogTransferTracker.Stats mockReplicaTranslogTrackerStats = createEmptyTranslogStats(shardId);
+        ShardRouting primaryShardRouting = createShardRouting(shardId, true);
+        ShardRouting replicaShardRouting = createShardRouting(shardId, false);
+        RemoteStoreStats primaryShardStats = new RemoteStoreStats(
+            mockPrimarySegmentTrackerStats,
+            mockPrimaryTranslogTrackerStats,
+            primaryShardRouting
+        );
+        RemoteStoreStats replicaShardStats = new RemoteStoreStats(
+            mockReplicaSegmentTrackerStats,
+            mockReplicaTranslogTrackerStats,
+            replicaShardRouting
+        );
+        RemoteStoreStatsResponse statsResponse = new RemoteStoreStatsResponse(
+            new RemoteStoreStats[] { primaryShardStats, replicaShardStats },
+            2,
+            2,
+            0,
+            new ArrayList<DefaultShardOperationFailedException>()
+        );
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        statsResponse.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonResponseObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType())
+            .v2();
+        Map<String, Object> metadataShardsObject = (Map<String, Object>) jsonResponseObject.get("_shards");
+        assertEquals(2, metadataShardsObject.get("total"));
+        assertEquals(2, metadataShardsObject.get("successful"));
+        assertEquals(0, metadataShardsObject.get("failed"));
+        Map<String, Object> indicesObject = (Map<String, Object>) jsonResponseObject.get("indices");
+        assertTrue(indicesObject.containsKey("index"));
+        Map<String, Object> shardsObject = (Map) ((Map) indicesObject.get("index")).get("shards");
+        ArrayList<Map<String, Object>> perShardNumberObject = (ArrayList<Map<String, Object>>) shardsObject.get("0");
+        assertEquals(2, perShardNumberObject.size());
+        perShardNumberObject.forEach(shardObject -> {
+            boolean isPrimary = (boolean) ((Map) shardObject.get(RemoteStoreStats.Fields.ROUTING)).get(
+                RemoteStoreStats.RoutingFields.PRIMARY
+            );
+            if (isPrimary) {
+                compareStatsResponse(shardObject, mockPrimarySegmentTrackerStats, mockPrimaryTranslogTrackerStats, primaryShardRouting);
+            } else {
+                compareStatsResponse(shardObject, mockReplicaSegmentTrackerStats, mockReplicaTranslogTrackerStats, replicaShardRouting);
+            }
+        });
+    }
+
+    public void testSerializationForBothRemoteStoreRestoredPrimaryAndReplica() throws Exception {
+        RemoteSegmentTransferTracker.Stats mockPrimarySegmentTrackerStats = createStatsForRemoteStoreRestoredPrimary(shardId);
+        RemoteSegmentTransferTracker.Stats mockReplicaSegmentTrackerStats = createStatsForNewReplica(shardId);
+        RemoteTranslogTransferTracker.Stats mockPrimaryTranslogTrackerStats = createTranslogStats(shardId);
+        RemoteTranslogTransferTracker.Stats mockReplicaTranslogTrackerStats = createEmptyTranslogStats(shardId);
+        ShardRouting primaryShardRouting = createShardRouting(shardId, true);
+        ShardRouting replicaShardRouting = createShardRouting(shardId, false);
+        RemoteStoreStats primaryShardStats = new RemoteStoreStats(
+            mockPrimarySegmentTrackerStats,
+            mockPrimaryTranslogTrackerStats,
+            primaryShardRouting
+        );
+        RemoteStoreStats replicaShardStats = new RemoteStoreStats(
+            mockReplicaSegmentTrackerStats,
+            mockReplicaTranslogTrackerStats,
+            replicaShardRouting
+        );
+        RemoteStoreStatsResponse statsResponse = new RemoteStoreStatsResponse(
+            new RemoteStoreStats[] { primaryShardStats, replicaShardStats },
+            2,
+            2,
+            0,
+            new ArrayList<DefaultShardOperationFailedException>()
+        );
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        statsResponse.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonResponseObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType())
+            .v2();
+        Map<String, Object> metadataShardsObject = (Map<String, Object>) jsonResponseObject.get("_shards");
+        assertEquals(2, metadataShardsObject.get("total"));
+        assertEquals(2, metadataShardsObject.get("successful"));
+        assertEquals(0, metadataShardsObject.get("failed"));
+        Map<String, Object> indicesObject = (Map<String, Object>) jsonResponseObject.get("indices");
+        assertTrue(indicesObject.containsKey("index"));
+        Map<String, Object> shardsObject = (Map) ((Map) indicesObject.get("index")).get("shards");
+        ArrayList<Map<String, Object>> perShardNumberObject = (ArrayList<Map<String, Object>>) shardsObject.get("0");
+        assertEquals(2, perShardNumberObject.size());
+        perShardNumberObject.forEach(shardObject -> {
+            boolean isPrimary = (boolean) ((Map) shardObject.get(RemoteStoreStats.Fields.ROUTING)).get(
+                RemoteStoreStats.RoutingFields.PRIMARY
+            );
+            if (isPrimary) {
+                compareStatsResponse(shardObject, mockPrimarySegmentTrackerStats, mockPrimaryTranslogTrackerStats, primaryShardRouting);
+            } else {
+                compareStatsResponse(shardObject, mockReplicaSegmentTrackerStats, mockReplicaTranslogTrackerStats, replicaShardRouting);
+            }
+        });
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTestHelper.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTestHelper.java
new file mode 100644
index 0000000000000..5886d47a7be24
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTestHelper.java
@@ -0,0 +1,417 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.TestShardRouting;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.store.DirectoryFileTransferTracker;
+
+import java.util.Map;
+
+import static org.opensearch.test.OpenSearchTestCase.assertEquals;
+import static org.opensearch.test.OpenSearchTestCase.randomAlphaOfLength;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Helper utilities for Remote Store stats tests
+ */
+public class RemoteStoreStatsTestHelper {
+    static RemoteSegmentTransferTracker.Stats createStatsForNewPrimary(ShardId shardId) {
+        return new RemoteSegmentTransferTracker.Stats(
+            shardId,
+            101,
+            102,
+            100,
+            0,
+            10,
+            2,
+            10,
+            5,
+            5,
+            0,
+            0,
+            0,
+            5,
+            5,
+            5,
+            0,
+            0,
+            0,
+            10,
+            createZeroDirectoryFileTransferStats()
+        );
+    }
+
+    static RemoteSegmentTransferTracker.Stats createStatsForNewReplica(ShardId shardId) {
+        return new RemoteSegmentTransferTracker.Stats(
+            shardId,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            createSampleDirectoryFileTransferStats()
+        );
+    }
+
+    static RemoteSegmentTransferTracker.Stats createStatsForRemoteStoreRestoredPrimary(ShardId shardId) {
+        return new RemoteSegmentTransferTracker.Stats(
+            shardId,
+            50,
+            50,
+            0,
+            50,
+            11,
+            11,
+            10,
+            10,
+            0,
+            10,
+            10,
+            0,
+            10,
+            10,
+            0,
+            0,
+            0,
+            100,
+            10,
+            createSampleDirectoryFileTransferStats()
+        );
+    }
+
+    static DirectoryFileTransferTracker.Stats createSampleDirectoryFileTransferStats() {
+        return new DirectoryFileTransferTracker.Stats(10, 0, 10, 12345, 5, 5, 5, 10);
+    }
+
+    static DirectoryFileTransferTracker.Stats createZeroDirectoryFileTransferStats() {
+        return new DirectoryFileTransferTracker.Stats(0, 0, 0, 0, 0, 0, 0, 0);
+    }
+
+    static ShardRouting createShardRouting(ShardId shardId, boolean isPrimary) {
+        return TestShardRouting.newShardRouting(shardId, randomAlphaOfLength(4), isPrimary, ShardRoutingState.STARTED);
+    }
+
+    static RemoteTranslogTransferTracker.Stats createTranslogStats(ShardId shardId) {
+        return new RemoteTranslogTransferTracker.Stats(shardId, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9D, 10D, 11D, 1L, 2L, 3L, 4L, 9D, 10D, 11D);
+    }
+
+    static RemoteTranslogTransferTracker.Stats createEmptyTranslogStats(ShardId shardId) {
+        return new RemoteTranslogTransferTracker.Stats(shardId, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0D, 0D, 0D, 0L, 0L, 0L, 0L, 0D, 0D, 0D);
+    }
+
+    static void compareStatsResponse(
+        Map<String, Object> statsObject,
+        RemoteSegmentTransferTracker.Stats segmentTransferStats,
+        RemoteTranslogTransferTracker.Stats translogTransferStats,
+        ShardRouting routing
+    ) {
+        // Compare Remote Segment Store stats
+        assertEquals(
+            ((Map) statsObject.get(RemoteStoreStats.Fields.ROUTING)).get(RemoteStoreStats.RoutingFields.NODE_ID),
+            routing.currentNodeId()
+        );
+        assertEquals(
+            ((Map) statsObject.get(RemoteStoreStats.Fields.ROUTING)).get(RemoteStoreStats.RoutingFields.STATE),
+            routing.state().toString()
+        );
+        assertEquals(
+            ((Map) statsObject.get(RemoteStoreStats.Fields.ROUTING)).get(RemoteStoreStats.RoutingFields.PRIMARY),
+            routing.primary()
+        );
+
+        Map<String, Object> segment = ((Map) statsObject.get(RemoteStoreStats.Fields.SEGMENT));
+        Map<String, Object> segmentDownloads = ((Map) segment.get(RemoteStoreStats.SubFields.DOWNLOAD));
+        Map<String, Object> segmentUploads = ((Map) segment.get(RemoteStoreStats.SubFields.UPLOAD));
+
+        if (segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesStarted != 0) {
+            assertEquals(
+                segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.LAST_SYNC_TIMESTAMP),
+                (int) segmentTransferStats.directoryFileTransferTrackerStats.lastTransferTimestampMs
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.STARTED_BYTES
+                ),
+                (int) segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesStarted
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.SUCCEEDED_BYTES
+                ),
+                (int) segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesSucceeded
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.FAILED_BYTES
+                ),
+                (int) segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesFailed
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.LAST_SUCCESSFUL
+                ),
+                (int) segmentTransferStats.directoryFileTransferTrackerStats.lastSuccessfulTransferInBytes
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                ),
+                segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesMovingAverage
+            );
+            assertEquals(
+                ((Map) segmentDownloads.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_SPEED_IN_BYTES_PER_SEC)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                ),
+                segmentTransferStats.directoryFileTransferTrackerStats.transferredBytesPerSecMovingAverage
+            );
+        } else {
+            assertTrue(segmentDownloads.isEmpty());
+        }
+
+        if (segmentTransferStats.totalUploadsStarted != 0) {
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.LOCAL_REFRESH_TIMESTAMP),
+                (int) segmentTransferStats.localRefreshClockTimeMs
+            );
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.REMOTE_REFRESH_TIMESTAMP),
+                (int) segmentTransferStats.remoteRefreshClockTimeMs
+            );
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.REFRESH_TIME_LAG_IN_MILLIS),
+                (int) segmentTransferStats.refreshTimeLagMs
+            );
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.REFRESH_LAG),
+                (int) (segmentTransferStats.localRefreshNumber - segmentTransferStats.remoteRefreshNumber)
+            );
+            assertEquals(segmentUploads.get(RemoteStoreStats.UploadStatsFields.BYTES_LAG), (int) segmentTransferStats.bytesLag);
+
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.BACKPRESSURE_REJECTION_COUNT),
+                (int) segmentTransferStats.rejectionCount
+            );
+            assertEquals(
+                segmentUploads.get(RemoteStoreStats.UploadStatsFields.CONSECUTIVE_FAILURE_COUNT),
+                (int) segmentTransferStats.consecutiveFailuresCount
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.STARTED_BYTES
+                ),
+                (int) segmentTransferStats.uploadBytesStarted
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.SUCCEEDED_BYTES
+                ),
+                (int) segmentTransferStats.uploadBytesSucceeded
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                    RemoteStoreStats.SubFields.FAILED_BYTES
+                ),
+                (int) segmentTransferStats.uploadBytesFailed
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.REMOTE_REFRESH_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                ),
+                segmentTransferStats.uploadBytesMovingAverage
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.REMOTE_REFRESH_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.LAST_SUCCESSFUL
+                ),
+                (int) segmentTransferStats.lastSuccessfulRemoteRefreshBytes
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.UPLOAD_SPEED_IN_BYTES_PER_SEC)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                ),
+                segmentTransferStats.uploadBytesPerSecMovingAverage
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(RemoteStoreStats.SubFields.STARTED),
+                (int) segmentTransferStats.totalUploadsStarted
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(RemoteStoreStats.SubFields.SUCCEEDED),
+                (int) segmentTransferStats.totalUploadsSucceeded
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(RemoteStoreStats.SubFields.FAILED),
+                (int) segmentTransferStats.totalUploadsFailed
+            );
+            assertEquals(
+                ((Map) segmentUploads.get(RemoteStoreStats.UploadStatsFields.REMOTE_REFRESH_LATENCY_IN_MILLIS)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                ),
+                segmentTransferStats.uploadTimeMovingAverage
+            );
+        } else {
+            assertTrue(segmentUploads.isEmpty());
+        }
+
+        // Compare Remote Translog Store stats
+        Map<?, ?> tlogStatsObj = (Map<?, ?>) statsObject.get(RemoteStoreStats.Fields.TRANSLOG);
+        Map<?, ?> tlogUploadStatsObj = (Map<?, ?>) tlogStatsObj.get(RemoteStoreStats.SubFields.UPLOAD);
+        if (translogTransferStats.totalUploadsStarted > 0) {
+            assertEquals(
+                translogTransferStats.lastSuccessfulUploadTimestamp,
+                Long.parseLong(tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.LAST_SUCCESSFUL_UPLOAD_TIMESTAMP).toString())
+            );
+
+            assertEquals(
+                translogTransferStats.totalUploadsStarted,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(
+                        RemoteStoreStats.SubFields.STARTED
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.totalUploadsSucceeded,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(
+                        RemoteStoreStats.SubFields.SUCCEEDED
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.totalUploadsFailed,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS)).get(
+                        RemoteStoreStats.SubFields.FAILED
+                    ).toString()
+                )
+            );
+
+            assertEquals(
+                translogTransferStats.uploadBytesStarted,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                        RemoteStoreStats.SubFields.STARTED_BYTES
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.uploadBytesSucceeded,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                        RemoteStoreStats.SubFields.SUCCEEDED_BYTES
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.uploadBytesFailed,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_SIZE)).get(
+                        RemoteStoreStats.SubFields.FAILED_BYTES
+                    ).toString()
+                )
+            );
+
+            assertEquals(
+                translogTransferStats.totalUploadTimeInMillis,
+                Long.parseLong(tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOAD_TIME_IN_MILLIS).toString())
+            );
+
+            assertEquals(
+                translogTransferStats.uploadBytesMovingAverage,
+                ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.UPLOAD_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+            assertEquals(
+                translogTransferStats.uploadBytesPerSecMovingAverage,
+                ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.UPLOAD_SPEED_IN_BYTES_PER_SEC)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+            assertEquals(
+                translogTransferStats.uploadTimeMovingAverage,
+                ((Map<?, ?>) tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.UPLOAD_TIME_IN_MILLIS)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+        } else {
+            assertNull(tlogUploadStatsObj.get(RemoteStoreStats.UploadStatsFields.TOTAL_UPLOADS));
+        }
+
+        Map<?, ?> tlogDownloadStatsObj = (Map<?, ?>) tlogStatsObj.get(RemoteStoreStats.SubFields.DOWNLOAD);
+        if (translogTransferStats.totalDownloadsSucceeded > 0) {
+            assertEquals(
+                translogTransferStats.lastSuccessfulDownloadTimestamp,
+                Long.parseLong(tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.LAST_SUCCESSFUL_DOWNLOAD_TIMESTAMP).toString())
+            );
+            assertEquals(
+                translogTransferStats.totalDownloadsSucceeded,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOADS)).get(
+                        RemoteStoreStats.SubFields.SUCCEEDED
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.downloadBytesSucceeded,
+                Long.parseLong(
+                    ((Map<?, ?>) tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_SIZE)).get(
+                        RemoteStoreStats.SubFields.SUCCEEDED_BYTES
+                    ).toString()
+                )
+            );
+            assertEquals(
+                translogTransferStats.totalDownloadTimeInMillis,
+                Long.parseLong(tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_TIME_IN_MILLIS).toString())
+            );
+
+            assertEquals(
+                translogTransferStats.downloadBytesMovingAverage,
+                ((Map<?, ?>) tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_SIZE_IN_BYTES)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+            assertEquals(
+                translogTransferStats.downloadBytesPerSecMovingAverage,
+                ((Map<?, ?>) tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_SPEED_IN_BYTES_PER_SEC)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+            assertEquals(
+                translogTransferStats.downloadTimeMovingAverage,
+                ((Map<?, ?>) tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.DOWNLOAD_TIME_IN_MILLIS)).get(
+                    RemoteStoreStats.SubFields.MOVING_AVG
+                )
+            );
+        } else {
+            assertNull(tlogDownloadStatsObj.get(RemoteStoreStats.DownloadStatsFields.TOTAL_DOWNLOAD_SIZE));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTests.java
new file mode 100644
index 0000000000000..1c78539a00a07
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/RemoteStoreStatsTests.java
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.Map;
+
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.compareStatsResponse;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createEmptyTranslogStats;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createShardRouting;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForNewPrimary;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForNewReplica;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createStatsForRemoteStoreRestoredPrimary;
+import static org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsTestHelper.createTranslogStats;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
+
+public class RemoteStoreStatsTests extends OpenSearchTestCase {
+    private ThreadPool threadPool;
+    private ShardId shardId;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("remote_store_stats_test");
+        shardId = new ShardId("index", "uuid", 0);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testXContentBuilderWithPrimaryShard() throws IOException {
+        RemoteSegmentTransferTracker.Stats segmentTransferStats = createStatsForNewPrimary(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createTranslogStats(shardId);
+        ShardRouting routing = createShardRouting(shardId, true);
+        RemoteStoreStats stats = new RemoteStoreStats(segmentTransferStats, translogTransferStats, routing);
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        stats.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType()).v2();
+        compareStatsResponse(jsonObject, segmentTransferStats, translogTransferStats, routing);
+    }
+
+    public void testXContentBuilderWithReplicaShard() throws IOException {
+        RemoteSegmentTransferTracker.Stats segmentTransferStats = createStatsForNewReplica(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createEmptyTranslogStats(shardId);
+        ShardRouting routing = createShardRouting(shardId, false);
+        RemoteStoreStats stats = new RemoteStoreStats(segmentTransferStats, translogTransferStats, routing);
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        stats.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType()).v2();
+        compareStatsResponse(jsonObject, segmentTransferStats, translogTransferStats, routing);
+    }
+
+    public void testXContentBuilderWithRemoteStoreRestoredShard() throws IOException {
+        RemoteSegmentTransferTracker.Stats segmentTransferStats = createStatsForRemoteStoreRestoredPrimary(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createTranslogStats(shardId);
+        ShardRouting routing = createShardRouting(shardId, true);
+        RemoteStoreStats stats = new RemoteStoreStats(segmentTransferStats, translogTransferStats, routing);
+
+        XContentBuilder builder = XContentFactory.jsonBuilder();
+        stats.toXContent(builder, EMPTY_PARAMS);
+        Map<String, Object> jsonObject = XContentHelper.convertToMap(BytesReference.bytes(builder), false, builder.contentType()).v2();
+        compareStatsResponse(jsonObject, segmentTransferStats, translogTransferStats, routing);
+    }
+
+    public void testSerializationForPrimaryShard() throws Exception {
+        RemoteSegmentTransferTracker.Stats segmentTransferStats = createStatsForNewPrimary(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createTranslogStats(shardId);
+        RemoteStoreStats stats = new RemoteStoreStats(segmentTransferStats, translogTransferStats, createShardRouting(shardId, true));
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            stats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteStoreStats deserializedStats = new RemoteStoreStats(in);
+                assertEquals(stats.getSegmentStats(), deserializedStats.getSegmentStats());
+                assertEquals(stats.getTranslogStats(), deserializedStats.getTranslogStats());
+            }
+        }
+    }
+
+    public void testSerializationForReplicaShard() throws Exception {
+        RemoteSegmentTransferTracker.Stats replicaShardStats = createStatsForNewReplica(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createEmptyTranslogStats(shardId);
+        RemoteStoreStats stats = new RemoteStoreStats(replicaShardStats, translogTransferStats, createShardRouting(shardId, false));
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            stats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteStoreStats deserializedStats = new RemoteStoreStats(in);
+                assertEquals(stats.getSegmentStats(), deserializedStats.getSegmentStats());
+                assertEquals(stats.getTranslogStats(), deserializedStats.getTranslogStats());
+            }
+        }
+    }
+
+    public void testSerializationForRemoteStoreRestoredPrimaryShard() throws Exception {
+        RemoteSegmentTransferTracker.Stats primaryShardStats = createStatsForRemoteStoreRestoredPrimary(shardId);
+        RemoteTranslogTransferTracker.Stats translogTransferStats = createTranslogStats(shardId);
+        RemoteStoreStats stats = new RemoteStoreStats(primaryShardStats, translogTransferStats, createShardRouting(shardId, true));
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            stats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteStoreStats deserializedStats = new RemoteStoreStats(in);
+                assertEquals(stats.getSegmentStats(), deserializedStats.getSegmentStats());
+                assertEquals(stats.getTranslogStats(), deserializedStats.getTranslogStats());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsActionTests.java
new file mode 100644
index 0000000000000..ed73c2ef6ace5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/remotestore/stats/TransportRemoteStoreStatsActionTests.java
@@ -0,0 +1,195 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.remotestore.stats;
+
+import org.opensearch.Version;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.PlainShardsIterator;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.ShardsIterator;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.transport.TransportService;
+
+import java.util.Collections;
+import java.util.stream.Collectors;
+
+import org.mockito.Mockito;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_INDEX_UUID;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+public class TransportRemoteStoreStatsActionTests extends IndexShardTestCase {
+    private IndicesService indicesService;
+    private RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+    private IndexMetadata remoteStoreIndexMetadata;
+    private TransportService transportService;
+    private ClusterService clusterService;
+    private TransportRemoteStoreStatsAction statsAction;
+    private DiscoveryNode localNode;
+    private static final Index INDEX = new Index("testIndex", "testUUID");
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        indicesService = mock(IndicesService.class);
+        IndexService indexService = mock(IndexService.class);
+        clusterService = mock(ClusterService.class);
+        remoteStoreStatsTrackerFactory = mock(RemoteStoreStatsTrackerFactory.class);
+        MockTransport mockTransport = new MockTransport();
+        localNode = new DiscoveryNode("node0", buildNewFakeTransportAddress(), Version.CURRENT);
+        remoteStoreIndexMetadata = IndexMetadata.builder(INDEX.getName())
+            .settings(
+                settings(Version.CURRENT).put(SETTING_INDEX_UUID, INDEX.getUUID())
+                    .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                    .put(SETTING_REMOTE_STORE_ENABLED, true)
+                    .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-test-repo")
+                    .build()
+            )
+            .numberOfShards(2)
+            .numberOfReplicas(1)
+            .build();
+        transportService = mockTransport.createTransportService(
+            Settings.EMPTY,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            x -> localNode,
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+        when(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(any())).thenReturn(mock(RemoteSegmentTransferTracker.class));
+        when(indicesService.indexService(INDEX)).thenReturn(indexService);
+        when(indexService.getIndexSettings()).thenReturn(new IndexSettings(remoteStoreIndexMetadata, Settings.EMPTY));
+        statsAction = new TransportRemoteStoreStatsAction(
+            clusterService,
+            transportService,
+            indicesService,
+            mock(ActionFilters.class),
+            mock(IndexNameExpressionResolver.class),
+            remoteStoreStatsTrackerFactory
+        );
+
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        transportService.close();
+        indicesService.close();
+        clusterService.close();
+    }
+
+    public void testAllShardCopies() throws Exception {
+        RoutingTable routingTable = RoutingTable.builder().addAsNew(remoteStoreIndexMetadata).build();
+        Metadata metadata = Metadata.builder().put(remoteStoreIndexMetadata, false).build();
+        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).routingTable(routingTable).build();
+
+        when(clusterService.getClusterSettings()).thenReturn(
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        when(clusterService.state()).thenReturn(clusterState);
+
+        ShardsIterator shardsIterator = statsAction.shards(
+            clusterService.state(),
+            new RemoteStoreStatsRequest(),
+            new String[] { INDEX.getName() }
+        );
+
+        assertEquals(shardsIterator.size(), 4);
+    }
+
+    public void testOnlyLocalShards() throws Exception {
+        String[] concreteIndices = new String[] { INDEX.getName() };
+        RoutingTable routingTable = spy(RoutingTable.builder().addAsNew(remoteStoreIndexMetadata).build());
+        doReturn(new PlainShardsIterator(routingTable.allShards(INDEX.getName()).stream().map(Mockito::spy).collect(Collectors.toList())))
+            .when(routingTable)
+            .allShards(concreteIndices);
+        routingTable.allShards(concreteIndices)
+            .forEach(
+                shardRouting -> doReturn(shardRouting.shardId().id() == 0 ? "node1" : localNode.getId()).when(shardRouting).currentNodeId()
+            );
+        Metadata metadata = Metadata.builder().put(remoteStoreIndexMetadata, false).build();
+        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(metadata)
+            .routingTable(routingTable)
+            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()))
+            .build();
+        when(clusterService.getClusterSettings()).thenReturn(
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        when(clusterService.state()).thenReturn(clusterState);
+        RemoteStoreStatsRequest remoteStoreStatsRequest = new RemoteStoreStatsRequest();
+        remoteStoreStatsRequest.local(true);
+        ShardsIterator shardsIterator = statsAction.shards(clusterService.state(), remoteStoreStatsRequest, concreteIndices);
+
+        assertEquals(shardsIterator.size(), 2);
+    }
+
+    public void testOnlyRemoteStoreEnabledShardCopies() throws Exception {
+        Index NEW_INDEX = new Index("newIndex", "newUUID");
+        IndexMetadata indexMetadataWithoutRemoteStore = IndexMetadata.builder(NEW_INDEX.getName())
+            .settings(
+                settings(Version.CURRENT).put(SETTING_INDEX_UUID, NEW_INDEX.getUUID()).put(SETTING_REMOTE_STORE_ENABLED, false).build()
+            )
+            .numberOfShards(2)
+            .numberOfReplicas(1)
+            .build();
+
+        RoutingTable routingTable = RoutingTable.builder()
+            .addAsNew(remoteStoreIndexMetadata)
+            .addAsNew(indexMetadataWithoutRemoteStore)
+            .build();
+        Metadata metadata = Metadata.builder().put(remoteStoreIndexMetadata, false).put(indexMetadataWithoutRemoteStore, false).build();
+        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).routingTable(routingTable).build();
+
+        IndexService newIndexService = mock(IndexService.class);
+
+        when(clusterService.getClusterSettings()).thenReturn(
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        when(clusterService.state()).thenReturn(clusterState);
+        when(indicesService.indexService(NEW_INDEX)).thenReturn(newIndexService);
+        when(newIndexService.getIndexSettings()).thenReturn(new IndexSettings(indexMetadataWithoutRemoteStore, Settings.EMPTY));
+
+        ShardsIterator shardsIterator = statsAction.shards(
+            clusterService.state(),
+            new RemoteStoreStatsRequest(),
+            new String[] { INDEX.getName() }
+        );
+
+        assertEquals(shardsIterator.size(), 4);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestTests.java
index 3d0b20582bdb0..51b3d9548c3a0 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/repositories/put/PutRepositoryRequestTests.java
@@ -31,11 +31,11 @@
 
 package org.opensearch.action.admin.cluster.repositories.put;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponseTests.java
index 473736732ef8e..1d9d6f4b27b72 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponseTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.action.admin.cluster.repositories.verify;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
index 3b7f2ff7f7ae2..129475e0fa3fb 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
@@ -32,25 +32,25 @@
 
 package org.opensearch.action.admin.cluster.reroute;
 
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
 import org.opensearch.action.support.master.AcknowledgedRequest;
-import org.opensearch.action.support.master.MasterNodeRequest;
 import org.opensearch.cluster.routing.allocation.command.AllocateEmptyPrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocateReplicaAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocateStalePrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.CancelAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.NetworkModule;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.admin.cluster.RestClusterRerouteAction;
 import org.opensearch.test.OpenSearchTestCase;
@@ -132,7 +132,7 @@ public void testEqualsAndHashCode() {
                 request.getCommands().commands().toArray(new AllocationCommand[0])
             );
             copy.dryRun(request.dryRun()).explain(request.explain()).timeout(request.timeout()).setRetryFailed(request.isRetryFailed());
-            copy.masterNodeTimeout(request.masterNodeTimeout());
+            copy.clusterManagerNodeTimeout(request.clusterManagerNodeTimeout());
             assertEquals(request, copy);
             assertEquals(copy, request); // Commutative
             assertEquals(request.hashCode(), copy.hashCode());
@@ -161,11 +161,11 @@ public void testEqualsAndHashCode() {
             assertEquals(request, copy);
             assertEquals(request.hashCode(), copy.hashCode());
 
-            // Changing masterNodeTime makes requests not equal
-            copy.masterNodeTimeout(timeValueMillis(request.masterNodeTimeout().millis() + 1));
+            // Changing clusterManagerNodeTimeout makes requests not equal
+            copy.clusterManagerNodeTimeout(timeValueMillis(request.clusterManagerNodeTimeout().millis() + 1));
             assertNotEquals(request, copy);
             assertNotEquals(request.hashCode(), copy.hashCode());
-            copy.masterNodeTimeout(request.masterNodeTimeout());
+            copy.clusterManagerNodeTimeout(request.clusterManagerNodeTimeout());
             assertEquals(request, copy);
             assertEquals(request.hashCode(), copy.hashCode());
 
@@ -212,7 +212,7 @@ private ClusterRerouteRequest roundTripThroughRestRequest(ClusterRerouteRequest
 
     private RestRequest toRestRequest(ClusterRerouteRequest original) throws IOException {
         Map<String, String> params = new HashMap<>();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         boolean hasBody = false;
         if (randomBoolean()) {
             builder.prettyPrint();
@@ -231,8 +231,9 @@ private RestRequest toRestRequest(ClusterRerouteRequest original) throws IOExcep
         if (original.isRetryFailed() || randomBoolean()) {
             params.put("retry_failed", Boolean.toString(original.isRetryFailed()));
         }
-        if (false == original.masterNodeTimeout().equals(MasterNodeRequest.DEFAULT_MASTER_NODE_TIMEOUT) || randomBoolean()) {
-            params.put("master_timeout", original.masterNodeTimeout().toString());
+        if (false == original.clusterManagerNodeTimeout().equals(ClusterManagerNodeRequest.DEFAULT_CLUSTER_MANAGER_NODE_TIMEOUT)
+            || randomBoolean()) {
+            params.put("cluster_manager_timeout", original.clusterManagerNodeTimeout().toString());
         }
         if (original.getCommands() != null) {
             hasBody = true;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponseTests.java
index 7a7bc18876932..d5a1d04bedc10 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteResponseTests.java
@@ -43,13 +43,11 @@
 import org.opensearch.cluster.routing.allocation.RoutingExplanations;
 import org.opensearch.cluster.routing.allocation.command.AllocateReplicaAllocationCommand;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -61,7 +59,7 @@ public class ClusterRerouteResponseTests extends OpenSearchTestCase {
 
     public void testToXContent() throws IOException {
         DiscoveryNode node0 = new DiscoveryNode("node0", new TransportAddress(TransportAddress.META_ADDRESS, 9000), Version.CURRENT);
-        DiscoveryNodes nodes = new DiscoveryNodes.Builder().add(node0).masterNodeId(node0.getId()).build();
+        DiscoveryNodes nodes = new DiscoveryNodes.Builder().add(node0).clusterManagerNodeId(node0.getId()).build();
         IndexMetadata indexMetadata = IndexMetadata.builder("index")
             .settings(
                 Settings.builder()
@@ -73,9 +71,9 @@ public void testToXContent() throws IOException {
                     .build()
             )
             .build();
-        ImmutableOpenMap.Builder<String, IndexMetadata> openMapBuilder = ImmutableOpenMap.builder();
+        final HashMap<String, IndexMetadata> openMapBuilder = new HashMap<>();
         openMapBuilder.put("index", indexMetadata);
-        Metadata metadata = Metadata.builder().indices(openMapBuilder.build()).build();
+        Metadata metadata = Metadata.builder().indices(openMapBuilder).build();
         ClusterState clusterState = ClusterState.builder(new ClusterName("test")).nodes(nodes).metadata(metadata).build();
 
         RoutingExplanations routingExplanations = new RoutingExplanations();
@@ -166,7 +164,7 @@ public void testToXContent() throws IOException {
                     + "    }\n"
                     + "  }\n"
                     + "}",
-                Strings.toString(builder)
+                builder.toString()
             );
 
         }
@@ -205,7 +203,7 @@ public void testToXContent() throws IOException {
                     + "    }\n"
                     + "  ]\n"
                     + "}",
-                Strings.toString(builder)
+                builder.toString()
             );
         }
         {
@@ -263,7 +261,7 @@ public void testToXContent() throws IOException {
                     + "    }\n"
                     + "  }\n"
                     + "}",
-                Strings.toString(builder)
+                builder.toString()
             );
         }
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteTests.java
index 859d8ce3bb734..bfa33628d822a 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteTests.java
@@ -32,10 +32,9 @@
 package org.opensearch.action.admin.cluster.reroute;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -46,14 +45,15 @@
 import org.opensearch.cluster.routing.allocation.command.AllocateEmptyPrimaryAllocationCommand;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.MaxRetryAllocationDecider;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponseTests.java
index d9f93da8e4ab2..5fa04e1dace30 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterGetSettingsResponseTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.cluster.settings;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestTests.java
index 2baa115f43c7d..505ed8fe9f600 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.action.admin.cluster.settings;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.XContentTestUtils;
 
@@ -59,14 +60,14 @@ public void testFromXContentWithRandomFields() throws IOException {
     private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws IOException {
         final ClusterUpdateSettingsRequest request = createTestItem();
         boolean humanReadable = randomBoolean();
-        final XContentType xContentType = XContentType.JSON;
-        BytesReference originalBytes = toShuffledXContent(request, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
+        final MediaType mediaType = MediaTypeRegistry.JSON;
+        BytesReference originalBytes = toShuffledXContent(request, mediaType, ToXContent.EMPTY_PARAMS, humanReadable);
 
         if (addRandomFields) {
             String unsupportedField = "unsupported_field";
             BytesReference mutated = BytesReference.bytes(
                 XContentTestUtils.insertIntoXContent(
-                    xContentType.xContent(),
+                    mediaType.xContent(),
                     originalBytes,
                     Collections.singletonList(""),
                     () -> unsupportedField,
@@ -75,11 +76,11 @@ private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws
             );
             XContentParseException iae = expectThrows(
                 XContentParseException.class,
-                () -> ClusterUpdateSettingsRequest.fromXContent(createParser(xContentType.xContent(), mutated))
+                () -> ClusterUpdateSettingsRequest.fromXContent(createParser(mediaType.xContent(), mutated))
             );
             assertThat(iae.getMessage(), containsString("[cluster_update_settings_request] unknown field [" + unsupportedField + "]"));
         } else {
-            try (XContentParser parser = createParser(xContentType.xContent(), originalBytes)) {
+            try (XContentParser parser = createParser(mediaType.xContent(), originalBytes)) {
                 ClusterUpdateSettingsRequest parsedRequest = ClusterUpdateSettingsRequest.fromXContent(parser);
 
                 assertNull(parser.nextToken());
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponseTests.java
index aee8f827a8312..3dbbd2a98bf08 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/settings/ClusterUpdateSettingsResponseTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.action.admin.cluster.settings;
 
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestTests.java
index 0c5414fcc512c..7b4e18f2ca818 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsRequestTests.java
@@ -36,7 +36,7 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponseTests.java
index 3c2e34ebb9ed5..d1e6d7d2353a5 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/shards/ClusterSearchShardsResponseTests.java
@@ -37,15 +37,15 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.RandomQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestTests.java
new file mode 100644
index 0000000000000..21248b11e69e5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/shards/routing/weighted/put/ClusterPutWeightedRoutingRequestTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.cluster.shards.routing.weighted.put;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Map;
+
+public class ClusterPutWeightedRoutingRequestTests extends OpenSearchTestCase {
+
+    public void testSetWeightedRoutingWeight() {
+        String reqString = "{\"weights\":{\"us-east-1c\":\"0\",\"us-east-1b\":\"1\",\"us-east-1a\":\"1\"},\"_version\":1}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest("zone");
+        Map<String, Double> weights = Map.of("us-east-1a", 1.0, "us-east-1b", 1.0, "us-east-1c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        assertEquals(weightedRouting, request.getWeightedRouting());
+        assertEquals(1, request.getVersion());
+    }
+
+    public void testValidate_ValuesAreProper() {
+        String reqString = "{\"weights\":{\"us-east-1c\":\"0\",\"us-east-1b\":\"1\",\"us-east-1a\":\"1\"},\"_version\":1}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest("zone");
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNull(actionRequestValidationException);
+    }
+
+    public void testValidate_MissingWeights() {
+        String reqString = "{}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest("zone");
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(actionRequestValidationException.getMessage().contains("Weights are missing"));
+    }
+
+    public void testValidate_AttributeMissing() {
+        String reqString = "{\"weights\":{\"us-east-1c\":\"0\",\"us-east-1b\":\"1\",\"us-east-1a\": \"1\"},\"_version\":1}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest();
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(actionRequestValidationException.getMessage().contains("Attribute name is missing"));
+    }
+
+    public void testValidate_MoreThanHalfWithZeroWeight() {
+        String reqString = "{\"weights\":{\"us-east-1c\":\"0\",\"us-east-1b\":\"0\",\"us-east-1a\": \"1\"}," + "\"_version\":1}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest("zone");
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(
+            actionRequestValidationException.getMessage().contains("Maximum expected number of routing weights having zero weight is [1]")
+        );
+    }
+
+    public void testValidate_VersionMissing() {
+        String reqString = "{\"weights\":{\"us-east-1c\": \"0\",\"us-east-1b\": \"1\",\"us-east-1a\": \"1\"}}";
+        ClusterPutWeightedRoutingRequest request = new ClusterPutWeightedRoutingRequest("zone");
+        request.setWeightedRouting(new BytesArray(reqString), MediaTypeRegistry.JSON);
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(actionRequestValidationException.getMessage().contains("Version is missing"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestTests.java
index a629f49c1f791..818a5f4c2f502 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestTests.java
@@ -36,14 +36,14 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.IndicesOptions.Option;
 import org.opensearch.action.support.IndicesOptions.WildcardStates;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent.MapParams;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent.MapParams;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -120,16 +120,16 @@ public void testToXContent() throws IOException {
         }
 
         if (randomBoolean()) {
-            original.masterNodeTimeout("60s");
+            original.clusterManagerNodeTimeout("60s");
         }
 
         XContentBuilder builder = original.toXContent(XContentFactory.jsonBuilder(), new MapParams(Collections.emptyMap()));
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(NamedXContentRegistry.EMPTY, null, BytesReference.bytes(builder).streamInput());
         Map<String, Object> map = parser.mapOrdered();
         CreateSnapshotRequest processed = new CreateSnapshotRequest((String) map.get("repository"), (String) map.get("snapshot"));
         processed.waitForCompletion(original.waitForCompletion());
-        processed.masterNodeTimeout(original.masterNodeTimeout());
+        processed.clusterManagerNodeTimeout(original.clusterManagerNodeTimeout());
         processed.source(map);
 
         assertEquals(original, processed);
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponseTests.java
index 205f17ba435e1..274a548fd98ab 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/create/CreateSnapshotResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.snapshots.create;
 
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotInfoTests;
@@ -94,7 +94,8 @@ protected CreateSnapshotResponse createTestInstance() {
                 totalShards,
                 shardFailures,
                 globalState,
-                SnapshotInfoTests.randomUserMetadata()
+                SnapshotInfoTests.randomUserMetadata(),
+                false
             )
         );
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponseTests.java
index 67c6a091f8762..3ef143e36dab9 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/get/GetSnapshotsResponseTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.admin.cluster.snapshots.get;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.snapshots.SnapshotInfoTests;
@@ -76,7 +76,8 @@ protected GetSnapshotsResponse createTestInstance() {
                     randomIntBetween(2, 3),
                     shardFailures,
                     randomBoolean(),
-                    SnapshotInfoTests.randomUserMetadata()
+                    SnapshotInfoTests.randomUserMetadata(),
+                    false
                 )
             );
         }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestTests.java
index 65c0bc5ae0639..c3de3413edd13 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestTests.java
@@ -33,14 +33,14 @@
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
@@ -105,13 +105,21 @@ private RestoreSnapshotRequest randomState(RestoreSnapshotRequest instance) {
         instance.waitForCompletion(randomBoolean());
 
         if (randomBoolean()) {
-            instance.masterNodeTimeout(randomTimeValue());
+            instance.clusterManagerNodeTimeout(randomTimeValue());
         }
 
         if (randomBoolean()) {
             instance.snapshotUuid(randomBoolean() ? null : randomAlphaOfLength(10));
         }
 
+        instance.storageType(
+            randomBoolean() ? RestoreSnapshotRequest.StorageType.LOCAL : RestoreSnapshotRequest.StorageType.REMOTE_SNAPSHOT
+        );
+
+        if (randomBoolean()) {
+            instance.setSourceRemoteStoreRepository(randomAlphaOfLengthBetween(5, 10));
+        }
+
         return instance;
     }
 
@@ -137,7 +145,7 @@ public void testSource() throws IOException {
         RestoreSnapshotRequest original = createTestInstance();
         original.snapshotUuid(null); // cannot be set via the REST API
         XContentBuilder builder = original.toXContent(XContentFactory.jsonBuilder(), new ToXContent.MapParams(Collections.emptyMap()));
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(NamedXContentRegistry.EMPTY, null, BytesReference.bytes(builder).streamInput());
         Map<String, Object> map = parser.mapOrdered();
 
@@ -145,7 +153,7 @@ public void testSource() throws IOException {
         // properties are restored from the original (in the actual REST action this is restored from the
         // REST path and request parameters).
         RestoreSnapshotRequest processed = new RestoreSnapshotRequest(original.repository(), original.snapshot());
-        processed.masterNodeTimeout(original.masterNodeTimeout());
+        processed.clusterManagerNodeTimeout(original.clusterManagerNodeTimeout());
         processed.waitForCompletion(original.waitForCompletion());
 
         processed.source(map);
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponseTests.java
index f1bcac57d83c5..d1f8524feda68 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/restore/RestoreSnapshotResponseTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.cluster.snapshots.restore;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.RestoreInfo;
 import org.opensearch.test.AbstractXContentTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatusTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatusTests.java
index aa7aa4274db4f..8ad973f6f819e 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatusTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexShardStatusTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import java.io.IOException;
-import java.util.function.Predicate;
-
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.test.AbstractXContentTestCase;
 
+import java.io.IOException;
+import java.util.function.Predicate;
+
 public class SnapshotIndexShardStatusTests extends AbstractXContentTestCase<SnapshotIndexShardStatus> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatusTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatusTests.java
index 024e37a93fe94..52c7ca5933134 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatusTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotIndexStatusTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
+import org.opensearch.test.AbstractXContentTestCase;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Predicate;
 
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
-import org.opensearch.test.AbstractXContentTestCase;
-
 public class SnapshotIndexStatusTests extends AbstractXContentTestCase<SnapshotIndexStatus> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStatsTests.java
index 3121f9a219bba..c5939e708d3a4 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotShardsStatsTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import java.io.IOException;
-
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
+import java.io.IOException;
+
 public class SnapshotShardsStatsTests extends AbstractXContentTestCase<SnapshotShardsStats> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatsTests.java
index 79e4c2fa70fb9..262f33ec76256 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatsTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
-import java.io.IOException;
-
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
+import java.io.IOException;
+
 public class SnapshotStatsTests extends AbstractXContentTestCase<SnapshotStats> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatusTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatusTests.java
index 28286805d0a75..3918e5d9b235c 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatusTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotStatusTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.AbstractXContentTestCase;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponseTests.java
index 5873fc96674b1..103a13d30d836 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/snapshots/status/SnapshotsStatusResponseTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.action.admin.cluster.snapshots.status;
 
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractXContentTestCase;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Predicate;
 
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.test.AbstractXContentTestCase;
-
 public class SnapshotsStatusResponseTests extends AbstractXContentTestCase<SnapshotsStatusResponse> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateApiTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateApiTests.java
index 039fde9455a2a..a87b50001b467 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateApiTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateApiTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.state;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestTests.java
index 7127e0001592f..91b024aaa1788 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateRequestTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateResponseTests.java
index 6455cd553f932..01f58bdbc73ff 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/state/ClusterStateResponseTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 public class ClusterStateResponseTests extends AbstractWireSerializingTestCase<ClusterStateResponse> {
@@ -49,7 +49,7 @@ protected ClusterStateResponse createTestInstance() {
         if (randomBoolean()) {
             ClusterState.Builder clusterStateBuilder = ClusterState.builder(clusterName).version(randomNonNegativeLong());
             if (randomBoolean()) {
-                clusterStateBuilder.nodes(DiscoveryNodes.builder().masterNodeId(randomAlphaOfLength(4)).build());
+                clusterStateBuilder.nodes(DiscoveryNodes.builder().clusterManagerNodeId(randomAlphaOfLength(4)).build());
             }
             clusterState = clusterStateBuilder.build();
         }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/stats/AnalysisStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/stats/AnalysisStatsTests.java
index 001836698057c..347e277e042ee 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/stats/AnalysisStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/stats/AnalysisStatsTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.cluster.stats;
 
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodesTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodesTests.java
index 9c0090a15d7a5..a0c45f95ef7c0 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodesTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/stats/ClusterStatsNodesTests.java
@@ -38,7 +38,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
@@ -51,7 +51,7 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.hamcrest.Matchers.equalTo;
 
 public class ClusterStatsNodesTests extends OpenSearchTestCase {
@@ -62,11 +62,17 @@ public class ClusterStatsNodesTests extends OpenSearchTestCase {
      */
     public void testNetworkTypesToXContent() throws Exception {
         ClusterStatsNodes.NetworkTypes stats = new ClusterStatsNodes.NetworkTypes(emptyList());
-        assertEquals("{\"transport_types\":{},\"http_types\":{}}", toXContent(stats, XContentType.JSON, randomBoolean()).utf8ToString());
+        assertEquals(
+            "{\"transport_types\":{},\"http_types\":{}}",
+            toXContent(stats, MediaTypeRegistry.JSON, randomBoolean()).utf8ToString()
+        );
 
         List<NodeInfo> nodeInfos = singletonList(createNodeInfo("node_0", null, null));
         stats = new ClusterStatsNodes.NetworkTypes(nodeInfos);
-        assertEquals("{\"transport_types\":{},\"http_types\":{}}", toXContent(stats, XContentType.JSON, randomBoolean()).utf8ToString());
+        assertEquals(
+            "{\"transport_types\":{},\"http_types\":{}}",
+            toXContent(stats, MediaTypeRegistry.JSON, randomBoolean()).utf8ToString()
+        );
 
         nodeInfos = Arrays.asList(
             createNodeInfo("node_1", "", ""),
@@ -76,7 +82,7 @@ public void testNetworkTypesToXContent() throws Exception {
         stats = new ClusterStatsNodes.NetworkTypes(nodeInfos);
         assertEquals(
             "{" + "\"transport_types\":{\"custom\":1}," + "\"http_types\":{\"custom\":2}" + "}",
-            toXContent(stats, XContentType.JSON, randomBoolean()).utf8ToString()
+            toXContent(stats, MediaTypeRegistry.JSON, randomBoolean()).utf8ToString()
         );
     }
 
@@ -89,15 +95,15 @@ public void testIngestStats() throws Exception {
                 processorStats.compute(stat.getType(), (key, value) -> {
                     if (value == null) {
                         return new long[] {
-                            stat.getStats().getIngestCount(),
-                            stat.getStats().getIngestFailedCount(),
-                            stat.getStats().getIngestCurrent(),
-                            stat.getStats().getIngestTimeInMillis() };
+                            stat.getStats().getCount(),
+                            stat.getStats().getFailedCount(),
+                            stat.getStats().getCurrent(),
+                            stat.getStats().getTotalTimeInMillis() };
                     } else {
-                        value[0] += stat.getStats().getIngestCount();
-                        value[1] += stat.getStats().getIngestFailedCount();
-                        value[2] += stat.getStats().getIngestCurrent();
-                        value[3] += stat.getStats().getIngestTimeInMillis();
+                        value[0] += stat.getStats().getCount();
+                        value[1] += stat.getStats().getFailedCount();
+                        value[2] += stat.getStats().getCurrent();
+                        value[3] += stat.getStats().getTotalTimeInMillis();
                         return value;
                     }
                 });
@@ -132,7 +138,7 @@ public void testIngestStats() throws Exception {
         }
         processorStatsString += "}";
         assertThat(
-            toXContent(stats, XContentType.JSON, false).utf8ToString(),
+            toXContent(stats, MediaTypeRegistry.JSON, false).utf8ToString(),
             equalTo(
                 "{\"ingest\":{"
                     + "\"number_of_pipelines\":"
@@ -167,6 +173,7 @@ private static NodeInfo createNodeInfo(String nodeId, String transportType, Stri
             null,
             null,
             null,
+            null,
             null
         );
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/stats/MappingStatsTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/stats/MappingStatsTests.java
index 9a4b89d975bc8..1b419d7ce77bd 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/stats/MappingStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/stats/MappingStatsTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.cluster.stats;
 
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponseTests.java
index f9ea3bf80f738..ac0777b9632db 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptContextResponseTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponseTests.java
index 24c5f4d0f254b..0dea4511304c1 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetScriptLanguageResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptLanguagesInfo;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestTests.java
index 9a248bec61220..ce1781edbce64 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.admin.cluster.storedscripts;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponseTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponseTests.java
index e0e18f7f54ee1..ebfd2a6761f46 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/GetStoredScriptResponseTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.script.StoredScriptSource;
 import org.opensearch.test.AbstractSerializingTestCase;
@@ -70,7 +70,7 @@ private static StoredScriptSource randomScriptSource() {
         final String lang = randomFrom("lang", "painless", "mustache");
         final String source = randomAlphaOfLengthBetween(1, 10);
         final Map<String, String> options = randomBoolean()
-            ? Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType())
+            ? Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
             : Collections.emptyMap();
         return new StoredScriptSource(lang, source, options);
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java
index 12c399418408f..491ecd0b7947d 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.StoredScriptSource;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -52,17 +53,17 @@ public void testSerialization() throws IOException {
             "bar",
             "context",
             new BytesArray("{}"),
-            XContentType.JSON,
+            MediaTypeRegistry.JSON,
             new StoredScriptSource("foo", "bar", Collections.emptyMap())
         );
 
-        assertEquals(XContentType.JSON, storedScriptRequest.xContentType());
+        assertEquals(MediaTypeRegistry.JSON, storedScriptRequest.mediaType());
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             storedScriptRequest.writeTo(output);
 
             try (StreamInput in = output.bytes().streamInput()) {
                 PutStoredScriptRequest serialized = new PutStoredScriptRequest(in);
-                assertEquals(XContentType.JSON, serialized.xContentType());
+                assertEquals(MediaTypeRegistry.JSON, serialized.mediaType());
                 assertEquals(storedScriptRequest.id(), serialized.id());
                 assertEquals(storedScriptRequest.context(), serialized.context());
             }
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptContextInfoSerializingTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptContextInfoSerializingTests.java
index 8203ec2078b2c..f478b3e9f5c98 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptContextInfoSerializingTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptContextInfoSerializingTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptContextInfo;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptMethodInfoSerializingTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptMethodInfoSerializingTests.java
index 8df2d8a1a2750..579ef9ebb1a70 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptMethodInfoSerializingTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptMethodInfoSerializingTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptContextInfo.ScriptMethodInfo;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptParameterInfoSerializingTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptParameterInfoSerializingTests.java
index bda3c8a89cac9..f6fe58ca8b0da 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptParameterInfoSerializingTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/storedscripts/ScriptParameterInfoSerializingTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptContextInfo.ScriptMethodInfo.ParameterInfo;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/TransportAnalyzeActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/TransportAnalyzeActionTests.java
index 17cc539a5d561..479321ec633da 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/TransportAnalyzeActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/TransportAnalyzeActionTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.action.admin.indices;
 
+import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.tests.analysis.MockTokenFilter;
 import org.apache.lucene.tests.analysis.MockTokenizer;
-import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.CharacterRunAutomaton;
 import org.opensearch.Version;
@@ -59,8 +59,8 @@
 import org.opensearch.indices.analysis.AnalysisModule.AnalysisProvider;
 import org.opensearch.indices.analysis.AnalysisModuleTests.AppendCharFilter;
 import org.opensearch.plugins.AnalysisPlugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -380,10 +380,9 @@ public void testGetIndexAnalyserWithoutIndexAnalyzers() {
 
     public void testGetFieldAnalyzerWithoutIndexAnalyzers() {
         AnalyzeAction.Request req = new AnalyzeAction.Request().field("field").text("text");
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { TransportAnalyzeAction.analyze(req, registry, null, maxTokenCount); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            TransportAnalyzeAction.analyze(req, registry, null, maxTokenCount);
+        });
         assertEquals(e.getMessage(), "analysis based on a specific field requires an index");
     }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/alias/AliasActionsTests.java b/server/src/test/java/org/opensearch/action/admin/indices/alias/AliasActionsTests.java
index 5ea5af7d8d553..8ba8d226715ed 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/alias/AliasActionsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/alias/AliasActionsTests.java
@@ -33,16 +33,15 @@
 package org.opensearch.action.admin.indices.alias;
 
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -195,7 +194,7 @@ public void testParseAdd() throws IOException {
             if (filter == null || filter.isEmpty()) {
                 assertNull(action.filter());
             } else {
-                assertEquals(Strings.toString(XContentFactory.contentBuilder(XContentType.JSON).map(filter)), action.filter());
+                assertEquals(MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON).map(filter).toString(), action.filter());
             }
             assertEquals(Objects.toString(searchRouting, null), action.searchRouting());
             assertEquals(Objects.toString(indexRouting, null), action.indexRouting());
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestTests.java
index 26ba4dde946b3..844d98f13b6d9 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/alias/IndicesAliasesRequestTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.admin.indices.alias;
 
 import org.opensearch.action.admin.indices.alias.IndicesAliasesRequest.AliasActions;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -73,7 +73,7 @@ private IndicesAliasesRequest createTestInstance() {
         }
 
         if (randomBoolean()) {
-            request.masterNodeTimeout(randomTimeValue());
+            request.clusterManagerNodeTimeout(randomTimeValue());
         }
         for (int i = 0; i < numItems; i++) {
             request.addAliasAction(randomAliasAction());
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponseTests.java
index 98a6aba1932d5..25bb1f8a92687 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/alias/get/GetAliasesResponseTests.java
@@ -34,14 +34,15 @@
 
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.AliasMetadata.Builder;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 public class GetAliasesResponseTests extends AbstractWireSerializingTestCase<GetAliasesResponse> {
@@ -61,26 +62,26 @@ protected GetAliasesResponse mutateInstance(GetAliasesResponse response) {
         return new GetAliasesResponse(mutateAliases(response.getAliases()));
     }
 
-    private static ImmutableOpenMap<String, List<AliasMetadata>> mutateAliases(ImmutableOpenMap<String, List<AliasMetadata>> aliases) {
+    private static Map<String, List<AliasMetadata>> mutateAliases(final Map<String, List<AliasMetadata>> aliases) {
         if (aliases.isEmpty()) {
-            return createIndicesAliasesMap(1, 3).build();
+            return createIndicesAliasesMap(1, 3);
         }
 
         if (randomBoolean()) {
-            ImmutableOpenMap.Builder<String, List<AliasMetadata>> builder = ImmutableOpenMap.builder(aliases);
-            ImmutableOpenMap<String, List<AliasMetadata>> list = createIndicesAliasesMap(1, 2).build();
-            list.forEach(e -> builder.put(e.key, e.value));
-            return builder.build();
+            final Map<String, List<AliasMetadata>> builder = new HashMap<>(aliases);
+            final Map<String, List<AliasMetadata>> list = createIndicesAliasesMap(1, 2);
+            list.forEach((k, v) -> builder.put(k, v));
+            return builder;
         }
 
         Set<String> indices = new HashSet<>();
-        Iterator<String> keys = aliases.keysIt();
+        Iterator<String> keys = aliases.keySet().iterator();
         while (keys.hasNext()) {
             indices.add(keys.next());
         }
 
         List<String> indicesToBeModified = randomSubsetOf(randomIntBetween(1, indices.size()), indices);
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> builder = ImmutableOpenMap.builder();
+        final Map<String, List<AliasMetadata>> builder = new HashMap<>();
 
         for (String index : indices) {
             List<AliasMetadata> list = new ArrayList<>(aliases.get(index));
@@ -95,15 +96,15 @@ private static ImmutableOpenMap<String, List<AliasMetadata>> mutateAliases(Immut
             }
             builder.put(index, list);
         }
-        return builder.build();
+        return builder;
     }
 
     private static GetAliasesResponse createTestItem() {
-        return new GetAliasesResponse(createIndicesAliasesMap(0, 5).build());
+        return new GetAliasesResponse(createIndicesAliasesMap(0, 5));
     }
 
-    private static ImmutableOpenMap.Builder<String, List<AliasMetadata>> createIndicesAliasesMap(int min, int max) {
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> builder = ImmutableOpenMap.builder();
+    private static Map<String, List<AliasMetadata>> createIndicesAliasesMap(int min, int max) {
+        final Map<String, List<AliasMetadata>> builder = new HashMap<>();
         int indicesNum = randomIntBetween(min, max);
         for (int i = 0; i < indicesNum; i++) {
             String index = randomAlphaOfLength(5);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesActionTests.java
index 46da611d9c2a7..0a223d7b6dc77 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/alias/get/TransportGetAliasesActionTests.java
@@ -36,13 +36,13 @@
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.indices.SystemIndexDescriptor;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import static org.hamcrest.Matchers.equalTo;
 
@@ -51,10 +51,8 @@ public class TransportGetAliasesActionTests extends OpenSearchTestCase {
 
     public void testPostProcess() {
         GetAliasesRequest request = new GetAliasesRequest();
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut("b", Collections.singletonList(new AliasMetadata.Builder("y").build()))
-            .build();
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        Map<String, List<AliasMetadata>> aliases = Map.of("b", Collections.singletonList(new AliasMetadata.Builder("y").build()));
+        Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             new String[] { "a", "b", "c" },
             aliases,
@@ -69,9 +67,7 @@ public void testPostProcess() {
 
         request = new GetAliasesRequest();
         request.replaceAliases("y", "z");
-        aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut("b", Collections.singletonList(new AliasMetadata.Builder("y").build()))
-            .build();
+        aliases = Map.of("b", Collections.singletonList(new AliasMetadata.Builder("y").build()));
         result = TransportGetAliasesAction.postProcess(
             request,
             new String[] { "a", "b", "c" },
@@ -86,9 +82,7 @@ public void testPostProcess() {
         assertThat(result.get("c").size(), equalTo(0));
 
         request = new GetAliasesRequest("y", "z");
-        aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut("b", Collections.singletonList(new AliasMetadata.Builder("y").build()))
-            .build();
+        aliases = Map.of("b", Collections.singletonList(new AliasMetadata.Builder("y").build()));
         result = TransportGetAliasesAction.postProcess(
             request,
             new String[] { "a", "b", "c" },
@@ -105,13 +99,15 @@ public void testDeprecationWarningEmittedForTotalWildcard() {
         ClusterState state = systemIndexTestClusterState();
 
         GetAliasesRequest request = new GetAliasesRequest();
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()))
-            .fPut("c", Collections.singletonList(new AliasMetadata.Builder("d").build()))
-            .build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of(
+            ".b",
+            Collections.singletonList(new AliasMetadata.Builder(".y").build()),
+            "c",
+            Collections.singletonList(new AliasMetadata.Builder("d").build())
+        );
         final String[] concreteIndices = { "a", ".b", "c" };
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
@@ -134,12 +130,10 @@ public void testDeprecationWarningEmittedWhenSystemIndexIsRequested() {
 
         GetAliasesRequest request = new GetAliasesRequest();
         request.indices(".b");
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()))
-            .build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()));
         final String[] concreteIndices = { ".b" };
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
@@ -159,12 +153,10 @@ public void testDeprecationWarningEmittedWhenSystemIndexIsRequestedByAlias() {
         ClusterState state = systemIndexTestClusterState();
 
         GetAliasesRequest request = new GetAliasesRequest(".y");
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()))
-            .build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()));
         final String[] concreteIndices = { "a", ".b", "c" };
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
@@ -184,12 +176,10 @@ public void testDeprecationWarningNotEmittedWhenSystemAccessAllowed() {
         ClusterState state = systemIndexTestClusterState();
 
         GetAliasesRequest request = new GetAliasesRequest(".y");
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()))
-            .build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of(".b", Collections.singletonList(new AliasMetadata.Builder(".y").build()));
         final String[] concreteIndices = { "a", ".b", "c" };
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
@@ -209,12 +199,10 @@ public void testDeprecationWarningNotEmittedWhenOnlyNonsystemIndexRequested() {
 
         GetAliasesRequest request = new GetAliasesRequest();
         request.indices("c");
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder()
-            .fPut("c", Collections.singletonList(new AliasMetadata.Builder("d").build()))
-            .build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of("c", Collections.singletonList(new AliasMetadata.Builder("d").build()));
         final String[] concreteIndices = { "c" };
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
@@ -236,10 +224,10 @@ public void testDeprecationWarningEmittedWhenRequestingNonExistingAliasInSystemP
         );
 
         GetAliasesRequest request = new GetAliasesRequest(".y");
-        ImmutableOpenMap<String, List<AliasMetadata>> aliases = ImmutableOpenMap.<String, List<AliasMetadata>>builder().build();
+        final Map<String, List<AliasMetadata>> aliases = Map.of();
         final String[] concreteIndices = {};
         assertEquals(state.metadata().findAliases(request, concreteIndices), aliases);
-        ImmutableOpenMap<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
+        final Map<String, List<AliasMetadata>> result = TransportGetAliasesAction.postProcess(
             request,
             concreteIndices,
             aliases,
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestTests.java
index d710801c489a5..9cb0e9b4329b0 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeRequestTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeResponseTests.java
index 8703cffec9dbc..4dfb901ce0cfd 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/analyze/AnalyzeResponseTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.action.admin.indices.analyze;
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction.AnalyzeToken;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.test.RandomObjects;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponseTests.java
index 1938459af9100..001e0380c8842 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/ClearIndicesCacheResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.indices.cache.clear;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractBroadcastResponseTestCase;
 
 import java.util.List;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheActionTests.java
new file mode 100644
index 0000000000000..1abd4c06e50e7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/cache/clear/TransportClearIndicesCacheActionTests.java
@@ -0,0 +1,135 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.cache.clear;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.block.ClusterBlock;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.block.ClusterBlocks;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.env.Environment;
+import org.opensearch.env.NodeEnvironment;
+import org.opensearch.env.TestEnvironment;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheFactory;
+import org.opensearch.index.store.remote.filecache.FileCacheTests;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.node.Node;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.EnumSet;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TransportClearIndicesCacheActionTests extends OpenSearchTestCase {
+
+    private final Node testNode = mock(Node.class);
+    private final TransportClearIndicesCacheAction action = new TransportClearIndicesCacheAction(
+        mock(ClusterService.class),
+        mock(TransportService.class),
+        mock(IndicesService.class),
+        testNode,
+        mock(ActionFilters.class),
+        mock(IndexNameExpressionResolver.class)
+    );
+
+    private final ClusterBlock writeClusterBlock = new ClusterBlock(
+        1,
+        "uuid",
+        "",
+        true,
+        true,
+        true,
+        RestStatus.OK,
+        EnumSet.of(ClusterBlockLevel.METADATA_WRITE)
+    );
+
+    private final ClusterBlock readClusterBlock = new ClusterBlock(
+        1,
+        "uuid",
+        "",
+        true,
+        true,
+        true,
+        RestStatus.OK,
+        EnumSet.of(ClusterBlockLevel.METADATA_READ)
+    );
+
+    public void testOnShardOperation() throws IOException {
+        final String indexName = "test";
+        final Settings settings = buildEnvSettings(Settings.EMPTY);
+        final Environment environment = TestEnvironment.newEnvironment(settings);
+        try (final NodeEnvironment nodeEnvironment = new NodeEnvironment(settings, environment)) {
+            // Initialize necessary stubs for the filecache clear shard operation
+            final ShardId shardId = new ShardId(indexName, indexName, 1);
+            final ShardRouting shardRouting = mock(ShardRouting.class);
+            when(shardRouting.shardId()).thenReturn(shardId);
+            final ShardPath shardPath = ShardPath.loadFileCachePath(nodeEnvironment, shardId);
+            final Path cacheEntryPath = shardPath.getDataPath();
+            final FileCache fileCache = FileCacheFactory.createConcurrentLRUFileCache(1024 * 1024, 16, new NoopCircuitBreaker(""));
+
+            when(testNode.fileCache()).thenReturn(fileCache);
+            when(testNode.getNodeEnvironment()).thenReturn(nodeEnvironment);
+
+            // Add an entry into the filecache and reduce the ref count
+            fileCache.put(cacheEntryPath, new FileCacheTests.StubCachedIndexInput(1));
+            fileCache.decRef(cacheEntryPath);
+
+            // Check if the entry exists and reduce the ref count to make it evictable
+            assertNotNull(fileCache.get(cacheEntryPath));
+            fileCache.decRef(cacheEntryPath);
+
+            ClearIndicesCacheRequest clearIndicesCacheRequest = new ClearIndicesCacheRequest();
+            clearIndicesCacheRequest.fileCache(true);
+            assertEquals(
+                TransportBroadcastByNodeAction.EmptyResult.INSTANCE,
+                action.shardOperation(clearIndicesCacheRequest, shardRouting)
+            );
+            assertNull(fileCache.get(cacheEntryPath));
+        }
+    }
+
+    public void testGlobalBlockCheck() {
+        ClusterBlocks.Builder builder = ClusterBlocks.builder();
+        builder.addGlobalBlock(writeClusterBlock);
+        ClusterState metadataWriteBlockedState = ClusterState.builder(ClusterState.EMPTY_STATE).blocks(builder).build();
+        assertNull(action.checkGlobalBlock(metadataWriteBlockedState, new ClearIndicesCacheRequest()));
+
+        builder = ClusterBlocks.builder();
+        builder.addGlobalBlock(readClusterBlock);
+        ClusterState metadataReadBlockedState = ClusterState.builder(ClusterState.EMPTY_STATE).blocks(builder).build();
+        assertNotNull(action.checkGlobalBlock(metadataReadBlockedState, new ClearIndicesCacheRequest()));
+    }
+
+    public void testIndexBlockCheck() {
+        String indexName = "test";
+        ClusterBlocks.Builder builder = ClusterBlocks.builder();
+        builder.addIndexBlock(indexName, writeClusterBlock);
+        ClusterState metadataWriteBlockedState = ClusterState.builder(ClusterState.EMPTY_STATE).blocks(builder).build();
+        assertNull(action.checkRequestBlock(metadataWriteBlockedState, new ClearIndicesCacheRequest(), new String[] { indexName }));
+
+        builder = ClusterBlocks.builder();
+        builder.addIndexBlock(indexName, readClusterBlock);
+        ClusterState metadataReadBlockedState = ClusterState.builder(ClusterState.EMPTY_STATE).blocks(builder).build();
+        assertNotNull(action.checkRequestBlock(metadataReadBlockedState, new ClearIndicesCacheRequest(), new String[] { indexName }));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexRequestTests.java
index fee026fcdcc9e..5206c833cfe10 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexRequestTests.java
@@ -37,8 +37,8 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -54,7 +54,7 @@ public void testSerialization() throws Exception {
                 deserializedRequest = new CloseIndexRequest(in);
             }
             assertEquals(request.timeout(), deserializedRequest.timeout());
-            assertEquals(request.masterNodeTimeout(), deserializedRequest.masterNodeTimeout());
+            assertEquals(request.clusterManagerNodeTimeout(), deserializedRequest.clusterManagerNodeTimeout());
             assertEquals(request.indicesOptions(), deserializedRequest.indicesOptions());
             assertEquals(request.getParentTask(), deserializedRequest.getParentTask());
             assertEquals(request.waitForActiveShards(), deserializedRequest.waitForActiveShards());
@@ -72,7 +72,7 @@ public void testBwcSerialization() throws Exception {
                 try (StreamInput in = out.bytes().streamInput()) {
                     in.setVersion(out.getVersion());
                     assertEquals(request.getParentTask(), TaskId.readFromStream(in));
-                    assertEquals(request.masterNodeTimeout(), in.readTimeValue());
+                    assertEquals(request.clusterManagerNodeTimeout(), in.readTimeValue());
                     assertEquals(request.timeout(), in.readTimeValue());
                     assertArrayEquals(request.indices(), in.readStringArray());
                     // indices options are not equivalent when sent to an older version and re-read due
@@ -96,7 +96,7 @@ public void testBwcSerialization() throws Exception {
             try (BytesStreamOutput out = new BytesStreamOutput()) {
                 out.setVersion(version);
                 sample.getParentTask().writeTo(out);
-                out.writeTimeValue(sample.masterNodeTimeout());
+                out.writeTimeValue(sample.clusterManagerNodeTimeout());
                 out.writeTimeValue(sample.timeout());
                 out.writeStringArray(sample.indices());
                 sample.indicesOptions().writeIndicesOptions(out);
@@ -110,7 +110,7 @@ public void testBwcSerialization() throws Exception {
                     deserializedRequest = new CloseIndexRequest(in);
                 }
                 assertEquals(sample.getParentTask(), deserializedRequest.getParentTask());
-                assertEquals(sample.masterNodeTimeout(), deserializedRequest.masterNodeTimeout());
+                assertEquals(sample.clusterManagerNodeTimeout(), deserializedRequest.clusterManagerNodeTimeout());
                 assertEquals(sample.timeout(), deserializedRequest.timeout());
                 assertArrayEquals(sample.indices(), deserializedRequest.indices());
                 // indices options are not equivalent when sent to an older version and re-read due
@@ -140,7 +140,7 @@ private CloseIndexRequest randomRequest() {
             request.timeout(randomPositiveTimeValue());
         }
         if (randomBoolean()) {
-            request.masterNodeTimeout(randomPositiveTimeValue());
+            request.clusterManagerNodeTimeout(randomPositiveTimeValue());
         }
         if (randomBoolean()) {
             request.setParentTask(randomAlphaOfLength(5), randomNonNegativeLong());
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexResponseTests.java
index 22de537942cde..bc092da6e72be 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/close/CloseIndexResponseTests.java
@@ -35,14 +35,15 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.admin.indices.close.CloseIndexResponse.IndexResult;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.transport.ActionNotFoundTransportException;
 
@@ -151,7 +152,7 @@ public void testToXContent() throws IOException {
         CloseIndexResponse closeIndexResponse = new CloseIndexResponse(true, true, Collections.singletonList(indexResult));
         assertEquals(
             "{\"acknowledged\":true,\"shards_acknowledged\":true,\"indices\":{\"test\":{\"closed\":true}}}",
-            Strings.toString(closeIndexResponse)
+            Strings.toString(MediaTypeRegistry.JSON, closeIndexResponse)
         );
 
         CloseIndexResponse.ShardResult[] shards = new CloseIndexResponse.ShardResult[1];
@@ -168,7 +169,7 @@ public void testToXContent() throws IOException {
                 + "\"failures\":[{\"node\":\"nodeId\",\"shard\":0,\"index\":\"test\",\"status\":\"INTERNAL_SERVER_ERROR\","
                 + "\"reason\":{\"type\":\"action_not_found_transport_exception\","
                 + "\"reason\":\"No handler for action [test]\"}}]}}}}}",
-            Strings.toString(closeIndexResponse)
+            Strings.toString(MediaTypeRegistry.JSON, closeIndexResponse)
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
index 72c7b5168fe15..ef26bc225b0c7 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.action.admin.indices.close;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.replication.FanoutReplicationProxy;
 import org.opensearch.action.support.replication.PendingReplicationActions;
+import org.opensearch.action.support.replication.ReplicationMode;
 import org.opensearch.action.support.replication.ReplicationOperation;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.action.support.replication.TransportReplicationAction;
@@ -52,24 +52,26 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
-import org.mockito.ArgumentCaptor;
 
 import java.util.Collections;
 import java.util.List;
@@ -77,7 +79,8 @@
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 
-import static org.mockito.Mockito.doNothing;
+import org.mockito.ArgumentCaptor;
+
 import static org.opensearch.action.support.replication.ClusterStateCreationUtils.state;
 import static org.opensearch.test.ClusterServiceUtils.createClusterService;
 import static org.opensearch.test.ClusterServiceUtils.setState;
@@ -87,6 +90,7 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
@@ -136,7 +140,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -290,7 +295,8 @@ public void testUnavailableShardsMarkedAsStale() throws Exception {
                 "test",
                 primaryTerm,
                 TimeValue.timeValueMillis(20),
-                TimeValue.timeValueSeconds(60)
+                TimeValue.timeValueSeconds(60),
+                new FanoutReplicationProxy<>(proxy)
             );
         operation.execute();
 
@@ -323,6 +329,32 @@ public void testUnavailableShardsMarkedAsStale() throws Exception {
         assertThat(shardInfo.getSuccessful(), equalTo(1 + nbReplicas - unavailableShards.size()));
     }
 
+    public void testGetReplicationModeWithRemoteTranslog() {
+        TransportVerifyShardBeforeCloseAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        TransportVerifyShardBeforeCloseAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportVerifyShardBeforeCloseAction createAction() {
+        return new TransportVerifyShardBeforeCloseAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            clusterService,
+            mock(IndicesService.class),
+            mock(ThreadPool.class),
+            mock(ShardStateAction.class),
+            mock(ActionFilters.class)
+        );
+    }
+
     private static
         ReplicationOperation.Primary<
             TransportVerifyShardBeforeCloseAction.ShardRequest,
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
index 5bb9155a5a84c..49561d18f70f2 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 import org.junit.After;
@@ -74,13 +74,12 @@ public void tearDown() throws Exception {
     public void testSetSource() throws IOException {
         CreateIndexRequestBuilder builder = new CreateIndexRequestBuilder(this.testClient, CreateIndexAction.INSTANCE);
 
-        OpenSearchParseException e = expectThrows(
-            OpenSearchParseException.class,
-            () -> { builder.setSource("{\"" + KEY + "\" : \"" + VALUE + "\"}", XContentType.JSON); }
-        );
+        OpenSearchParseException e = expectThrows(OpenSearchParseException.class, () -> {
+            builder.setSource("{\"" + KEY + "\" : \"" + VALUE + "\"}", MediaTypeRegistry.JSON);
+        });
         assertEquals(String.format(Locale.ROOT, "unknown key [%s] for create index", KEY), e.getMessage());
 
-        builder.setSource("{\"settings\" : {\"" + KEY + "\" : \"" + VALUE + "\"}}", XContentType.JSON);
+        builder.setSource("{\"settings\" : {\"" + KEY + "\" : \"" + VALUE + "\"}}", MediaTypeRegistry.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         XContentBuilder xContent = XContentFactory.jsonBuilder()
@@ -101,7 +100,7 @@ public void testSetSource() throws IOException {
             .endObject()
             .endObject();
         doc.close();
-        builder.setSource(docOut.toByteArray(), XContentType.JSON);
+        builder.setSource(docOut.toByteArray(), MediaTypeRegistry.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         Map<String, String> settingsMap = new HashMap<>();
@@ -118,7 +117,7 @@ public void testSetSettings() throws IOException {
         builder.setSettings(Settings.builder().put(KEY, VALUE));
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
-        builder.setSettings("{\"" + KEY + "\" : \"" + VALUE + "\"}", XContentType.JSON);
+        builder.setSettings("{\"" + KEY + "\" : \"" + VALUE + "\"}", MediaTypeRegistry.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         builder.setSettings(Settings.builder().put(KEY, VALUE));
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestTests.java
index 31039826868ac..398d9e3338580 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexRequestTests.java
@@ -34,16 +34,15 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.action.admin.indices.alias.Alias;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -57,9 +56,12 @@ public class CreateIndexRequestTests extends OpenSearchTestCase {
 
     public void testSerialization() throws IOException {
         CreateIndexRequest request = new CreateIndexRequest("foo");
-        String mapping = Strings.toString(
-            JsonXContent.contentBuilder().startObject().startObject(MapperService.SINGLE_MAPPING_NAME).endObject().endObject()
-        );
+        String mapping = JsonXContent.contentBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .endObject()
+            .endObject()
+            .toString();
         request.mapping(mapping);
 
         try (BytesStreamOutput output = new BytesStreamOutput()) {
@@ -92,7 +94,7 @@ public void testTopLevelKeys() {
         CreateIndexRequest request = new CreateIndexRequest();
         OpenSearchParseException e = expectThrows(
             OpenSearchParseException.class,
-            () -> { request.source(createIndex, XContentType.JSON); }
+            () -> { request.source(createIndex, MediaTypeRegistry.JSON); }
         );
         assertEquals("unknown key [FOO_SHOULD_BE_ILLEGAL_HERE] for create index", e.getMessage());
     }
@@ -101,7 +103,7 @@ public void testMappingKeyedByType() throws IOException {
         CreateIndexRequest request1 = new CreateIndexRequest("foo");
         CreateIndexRequest request2 = new CreateIndexRequest("bar");
         {
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject()
                 .startObject("properties")
                 .startObject("field1")
@@ -117,7 +119,7 @@ public void testMappingKeyedByType() throws IOException {
                 .endObject()
                 .endObject();
             request1.mapping(builder);
-            builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject()
                 .startObject(MapperService.SINGLE_MAPPING_NAME)
                 .startObject("properties")
@@ -140,7 +142,7 @@ public void testMappingKeyedByType() throws IOException {
     }
 
     public void testSettingsType() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         builder.startObject().startArray("settings").endArray().endObject();
 
         CreateIndexRequest parsedCreateIndexRequest = new CreateIndexRequest();
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexResponseTests.java
index a51b256d32010..d989cbc2b3488 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/create/CreateIndexResponseTests.java
@@ -32,10 +32,11 @@
 
 package org.opensearch.action.admin.indices.create;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -83,13 +84,13 @@ protected CreateIndexResponse doParseInstance(XContentParser parser) {
 
     public void testToXContent() {
         CreateIndexResponse response = new CreateIndexResponse(true, false, "index_name");
-        String output = Strings.toString(response);
+        String output = Strings.toString(MediaTypeRegistry.JSON, response);
         assertEquals("{\"acknowledged\":true,\"shards_acknowledged\":false,\"index\":\"index_name\"}", output);
     }
 
     public void testToAndFromXContentIndexNull() throws IOException {
         CreateIndexResponse response = new CreateIndexResponse(true, false, null);
-        String output = Strings.toString(response);
+        String output = Strings.toString(MediaTypeRegistry.JSON, response);
         assertEquals("{\"acknowledged\":true,\"shards_acknowledged\":false,\"index\":null}", output);
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, output)) {
             CreateIndexResponse parsedResponse = CreateIndexResponse.fromXContent(parser);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamRequestTests.java
index 0d7f451a0f3fc..4df2ef286edf9 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/datastream/CreateDataStreamRequestTests.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.datastream.CreateDataStreamAction.Request;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import static org.hamcrest.Matchers.containsString;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsResponseTests.java
index a88868173b951..c83263e4e22c6 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/datastream/DataStreamsStatsResponseTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.admin.indices.datastream;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamRequestTests.java
index b6e143d28b4aa..25ab80ebf379f 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/datastream/DeleteDataStreamRequestTests.java
@@ -41,12 +41,11 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataDeleteIndexService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInProgressException;
@@ -56,6 +55,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -95,11 +95,8 @@ public void testValidateRequestWithoutName() {
 
     public void testDeleteDataStream() {
         final String dataStreamName = "my-data-stream";
-        final List<String> otherIndices = randomSubsetOf(org.opensearch.common.collect.List.of("foo", "bar", "baz"));
-        ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamName, 2)),
-            otherIndices
-        );
+        final List<String> otherIndices = randomSubsetOf(List.of("foo", "bar", "baz"));
+        ClusterState cs = getClusterStateWithDataStreams(List.of(new Tuple<>(dataStreamName, 2)), otherIndices);
         DeleteDataStreamAction.Request req = new DeleteDataStreamAction.Request(new String[] { dataStreamName });
         ClusterState newState = DeleteDataStreamAction.TransportAction.removeDataStream(getMetadataDeleteIndexService(), cs, req);
         assertThat(newState.metadata().dataStreams().size(), equalTo(0));
@@ -112,13 +109,13 @@ public void testDeleteDataStream() {
     public void testDeleteMultipleDataStreams() {
         String[] dataStreamNames = { "foo", "bar", "baz", "eggplant" };
         ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(
+            List.of(
                 new Tuple<>(dataStreamNames[0], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[1], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[2], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[3], randomIntBetween(1, 3))
             ),
-            org.opensearch.common.collect.List.of()
+            List.of()
         );
 
         DeleteDataStreamAction.Request req = new DeleteDataStreamAction.Request(new String[] { "ba*", "eggplant" });
@@ -171,10 +168,10 @@ private SnapshotsInProgress.Entry createEntry(String dataStreamName, String repo
             Collections.singletonList(dataStreamName),
             0,
             1,
-            ImmutableOpenMap.of(),
+            Map.of(),
             null,
             null,
-            null
+            false
         );
     }
 
@@ -182,13 +179,13 @@ public void testDeleteNonexistentDataStream() {
         final String dataStreamName = "my-data-stream";
         String[] dataStreamNames = { "foo", "bar", "baz", "eggplant" };
         ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(
+            List.of(
                 new Tuple<>(dataStreamNames[0], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[1], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[2], randomIntBetween(1, 3)),
                 new Tuple<>(dataStreamNames[3], randomIntBetween(1, 3))
             ),
-            org.opensearch.common.collect.List.of()
+            List.of()
         );
         DeleteDataStreamAction.Request req = new DeleteDataStreamAction.Request(new String[] { dataStreamName });
         ClusterState newState = DeleteDataStreamAction.TransportAction.removeDataStream(getMetadataDeleteIndexService(), cs, req);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsRequestTests.java
index 25734a9824c41..c1b1608d5f7a8 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsRequestTests.java
@@ -37,9 +37,9 @@
 import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
@@ -82,10 +82,7 @@ protected Request createTestInstance() {
 
     public void testGetDataStream() {
         final String dataStreamName = "my-data-stream";
-        ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamName, 1)),
-            org.opensearch.common.collect.List.of()
-        );
+        ClusterState cs = getClusterStateWithDataStreams(List.of(new Tuple<>(dataStreamName, 1)), List.of());
         GetDataStreamAction.Request req = new GetDataStreamAction.Request(new String[] { dataStreamName });
         List<DataStream> dataStreams = GetDataStreamAction.TransportAction.getDataStreams(
             cs,
@@ -99,8 +96,8 @@ public void testGetDataStream() {
     public void testGetDataStreamsWithWildcards() {
         final String[] dataStreamNames = { "my-data-stream", "another-data-stream" };
         ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamNames[0], 1), new Tuple<>(dataStreamNames[1], 1)),
-            org.opensearch.common.collect.List.of()
+            List.of(new Tuple<>(dataStreamNames[0], 1), new Tuple<>(dataStreamNames[1], 1)),
+            List.of()
         );
 
         GetDataStreamAction.Request req = new GetDataStreamAction.Request(new String[] { dataStreamNames[1].substring(0, 5) + "*" });
@@ -144,8 +141,8 @@ public void testGetDataStreamsWithWildcards() {
     public void testGetDataStreamsWithoutWildcards() {
         final String[] dataStreamNames = { "my-data-stream", "another-data-stream" };
         ClusterState cs = getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamNames[0], 1), new Tuple<>(dataStreamNames[1], 1)),
-            org.opensearch.common.collect.List.of()
+            List.of(new Tuple<>(dataStreamNames[0], 1), new Tuple<>(dataStreamNames[1], 1)),
+            List.of()
         );
 
         GetDataStreamAction.Request req = new GetDataStreamAction.Request(new String[] { dataStreamNames[0], dataStreamNames[1] });
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsResponseTests.java
index 5863ee7d328bd..20e77dc68da09 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/datastream/GetDataStreamsResponseTests.java
@@ -34,8 +34,9 @@
 import org.opensearch.action.admin.indices.datastream.GetDataStreamAction.Response;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.metadata.DataStreamTests;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
+
 import java.util.ArrayList;
 import java.util.List;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/flush/FlushResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/flush/FlushResponseTests.java
index 5cce341427020..391d367da0c6d 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/flush/FlushResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/flush/FlushResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.indices.flush;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractBroadcastResponseTestCase;
 
 import java.util.List;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/flush/TransportShardFlushActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/flush/TransportShardFlushActionTests.java
new file mode 100644
index 0000000000000..09215088bd04b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/flush/TransportShardFlushActionTests.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.flush;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TransportShardFlushActionTests extends OpenSearchTestCase {
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        TransportShardFlushAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        TransportShardFlushAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportShardFlushAction createAction() {
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        return new TransportShardFlushAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            clusterService,
+            mock(IndicesService.class),
+            mock(ThreadPool.class),
+            mock(ShardStateAction.class),
+            mock(ActionFilters.class)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponseTests.java
index 97e52c99992be..f6bcec5e8fb42 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/ForceMergeResponseTests.java
@@ -32,13 +32,32 @@
 
 package org.opensearch.action.admin.indices.forcemerge;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.OpenSearchException;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractBroadcastResponseTestCase;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class ForceMergeResponseTests extends AbstractBroadcastResponseTestCase<ForceMergeResponse> {
+
+    public void testToString() {
+        String indexName = randomAlphaOfLengthBetween(3, 10);
+        int shardId = randomIntBetween(0, 10);
+        List<DefaultShardOperationFailedException> exceptions = new ArrayList<>();
+        exceptions.add(new DefaultShardOperationFailedException(indexName, shardId, new OpenSearchException("boom")));
+        ForceMergeResponse response = createTestInstance(10, 3, 1, exceptions);
+        assertEquals(
+            "ForceMergeResponse[total_shards=10,successful_shards=3,failed_shards=1,failures=[["
+                + indexName
+                + "]["
+                + shardId
+                + "] failed, reason [OpenSearchException[boom]]]]",
+            response.toString()
+        );
+    }
+
     @Override
     protected ForceMergeResponse createTestInstance(
         int totalShards,
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/RestForceMergeActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/RestForceMergeActionTests.java
index 31b01ed6f05c8..b09e592922ed9 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/RestForceMergeActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/forcemerge/RestForceMergeActionTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.admin.indices.forcemerge;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.admin.indices.RestForceMergeAction;
 import org.opensearch.test.rest.FakeRestChannel;
@@ -62,7 +62,7 @@ public void testBodyRejection() throws Exception {
         String json = JsonXContent.contentBuilder().startObject().field("max_num_segments", 1).endObject().toString();
         final FakeRestRequest request = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY).withContent(
             new BytesArray(json),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).withPath("/_forcemerge").build();
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexActionTests.java
index 5648f14fa69dd..2d9ec2b6d3c02 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.indices.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ClusterStateCreationUtils;
@@ -44,8 +43,10 @@
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.settings.SettingsModule;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -85,7 +86,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -109,7 +111,9 @@ public void testIncludeDefaults() {
                     "index.refresh_interval should be set as we are including defaults",
                     defaultsResponse.getSetting(indexName, "index.refresh_interval")
                 ),
-                exception -> { throw new AssertionError(exception); }
+                exception -> {
+                    throw new AssertionError(exception);
+                }
             )
         );
     }
@@ -124,7 +128,9 @@ public void testDoNotIncludeDefaults() {
                     "index.refresh_interval should be null as it was never set",
                     noDefaultsResponse.getSetting(indexName, "index.refresh_interval")
                 ),
-                exception -> { throw new AssertionError(exception); }
+                exception -> {
+                    throw new AssertionError(exception);
+                }
             )
         );
     }
@@ -145,14 +151,14 @@ class TestTransportGetIndexAction extends TransportGetIndexAction {
         }
 
         @Override
-        protected void doMasterOperation(
+        protected void doClusterManagerOperation(
             GetIndexRequest request,
             String[] concreteIndices,
             ClusterState state,
             ActionListener<GetIndexResponse> listener
         ) {
             ClusterState stateWithIndex = ClusterStateCreationUtils.state(indexName, 1, 1);
-            super.doMasterOperation(request, concreteIndices, stateWithIndex, listener);
+            super.doClusterManagerOperation(request, concreteIndices, stateWithIndex, listener);
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexRequestTests.java
new file mode 100644
index 0000000000000..f0d3db71c27b7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexRequestTests.java
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.get;
+
+import org.opensearch.action.support.master.info.ClusterInfoRequest;
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.hamcrest.Matchers.is;
+
+public class GetIndexRequestTests extends OpenSearchTestCase {
+    public void testGetIndexRequestExtendsClusterInfoRequestOfDeprecatedClassPath() {
+        GetIndexRequest getIndexRequest = new GetIndexRequest().indices("test");
+        assertThat(getIndexRequest instanceof ClusterInfoRequest, is(true));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexResponseTests.java
index f712b93b409dc..89d47328a08ed 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/get/GetIndexResponseTests.java
@@ -37,18 +37,19 @@
 import org.opensearch.action.admin.indices.mapping.get.GetMappingsResponseTests;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 
 public class GetIndexResponseTests extends AbstractWireSerializingTestCase<GetIndexResponse> {
 
@@ -60,11 +61,11 @@ protected Writeable.Reader<GetIndexResponse> instanceReader() {
     @Override
     protected GetIndexResponse createTestInstance() {
         String[] indices = generateRandomStringArray(5, 5, false, false);
-        ImmutableOpenMap.Builder<String, MappingMetadata> mappings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, List<AliasMetadata>> aliases = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, Settings> settings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, Settings> defaultSettings = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, String> dataStreams = ImmutableOpenMap.builder();
+        final Map<String, MappingMetadata> mappings = new HashMap<>();
+        final Map<String, List<AliasMetadata>> aliases = new HashMap<>();
+        Map<String, Settings> settings = new HashMap<>();
+        Map<String, Settings> defaultSettings = new HashMap<>();
+        Map<String, String> dataStreams = new HashMap<>();
         IndexScopedSettings indexScopedSettings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS;
         boolean includeDefaults = randomBoolean();
         for (String index : indices) {
@@ -90,13 +91,6 @@ protected GetIndexResponse createTestInstance() {
                 dataStreams.put(index, randomAlphaOfLength(5).toLowerCase(Locale.ROOT));
             }
         }
-        return new GetIndexResponse(
-            indices,
-            mappings.build(),
-            aliases.build(),
-            settings.build(),
-            defaultSettings.build(),
-            dataStreams.build()
-        );
+        return new GetIndexResponse(indices, mappings, aliases, settings, defaultSettings, dataStreams);
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java
index 512e21cc28469..23cf0ce14a8bd 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java
@@ -33,11 +33,12 @@
 package org.opensearch.action.admin.indices.mapping.get;
 
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsResponse.FieldMappingMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
@@ -68,7 +69,7 @@ public void testNullFieldMappingToXContent() {
         Map<String, Map<String, FieldMappingMetadata>> mappings = new HashMap<>();
         mappings.put("index", Collections.emptyMap());
         GetFieldMappingsResponse response = new GetFieldMappingsResponse(mappings);
-        assertEquals("{\"index\":{\"mappings\":{}}}", Strings.toString(response));
+        assertEquals("{\"index\":{\"mappings\":{}}}", Strings.toString(MediaTypeRegistry.JSON, response));
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponseTests.java
index 5dd05789429bf..fa8eeb7389b43 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/mapping/get/GetMappingsResponseTests.java
@@ -33,8 +33,7 @@
 package org.opensearch.action.admin.indices.mapping.get;
 
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
@@ -57,11 +56,11 @@ protected Writeable.Reader<GetMappingsResponse> instanceReader() {
     }
 
     private static GetMappingsResponse mutate(GetMappingsResponse original) {
-        ImmutableOpenMap.Builder<String, MappingMetadata> builder = ImmutableOpenMap.builder(original.mappings());
-        String indexKey = original.mappings().keys().iterator().next().value;
+        final Map<String, MappingMetadata> builder = new HashMap<>(original.mappings());
+        String indexKey = original.mappings().keySet().iterator().next();
         builder.put(indexKey + "1", createMappingsForIndex());
 
-        return new GetMappingsResponse(builder.build());
+        return new GetMappingsResponse(builder);
     }
 
     @Override
@@ -84,9 +83,9 @@ public static MappingMetadata createMappingsForIndex() {
 
     @Override
     protected GetMappingsResponse createTestInstance() {
-        ImmutableOpenMap.Builder<String, MappingMetadata> indexBuilder = ImmutableOpenMap.builder();
+        final Map<String, MappingMetadata> indexBuilder = new HashMap<>();
         indexBuilder.put("index-" + randomAlphaOfLength(5), createMappingsForIndex());
-        GetMappingsResponse resp = new GetMappingsResponse(indexBuilder.build());
+        GetMappingsResponse resp = new GetMappingsResponse(indexBuilder);
         logger.debug("--> created: {}", resp);
         return resp;
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
index d8178769ba7b1..377e2bd0c9397 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
@@ -40,16 +40,17 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -59,7 +60,7 @@
 import java.util.stream.Collectors;
 
 import static org.opensearch.common.collect.Tuple.tuple;
-import static org.opensearch.common.xcontent.ToXContent.EMPTY_PARAMS;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 
@@ -72,12 +73,12 @@ public void testValidation() {
         assertNotNull("source validation should fail", ex);
         assertTrue(ex.getMessage().contains("source is missing"));
 
-        r.source("", XContentType.JSON);
+        r.source("", MediaTypeRegistry.JSON);
         ex = r.validate();
         assertNotNull("source validation should fail", ex);
         assertTrue(ex.getMessage().contains("source is empty"));
 
-        r.source("somevalidmapping", XContentType.JSON);
+        r.source("somevalidmapping", MediaTypeRegistry.JSON);
         ex = r.validate();
         assertNull("validation should succeed", ex);
 
@@ -113,7 +114,7 @@ public void testToXContent() throws IOException {
         mapping.endObject();
         request.source(mapping);
 
-        String actualRequestBody = Strings.toString(request);
+        String actualRequestBody = Strings.toString(MediaTypeRegistry.JSON, request);
         String expectedRequestBody = "{\"properties\":{\"email\":{\"type\":\"text\"}}}";
         assertEquals(expectedRequestBody, actualRequestBody);
     }
@@ -121,7 +122,7 @@ public void testToXContent() throws IOException {
     public void testToXContentWithEmptySource() throws IOException {
         PutMappingRequest request = new PutMappingRequest("foo");
 
-        String actualRequestBody = Strings.toString(request);
+        String actualRequestBody = Strings.toString(MediaTypeRegistry.JSON, request);
         String expectedRequestBody = "{}";
         assertEquals(expectedRequestBody, actualRequestBody);
     }
@@ -143,8 +144,8 @@ public void testToAndFromXContent() throws IOException {
     private void assertMappingsEqual(String expected, String actual) throws IOException {
 
         try (
-            XContentParser expectedJson = createParser(XContentType.JSON.xContent(), expected);
-            XContentParser actualJson = createParser(XContentType.JSON.xContent(), actual)
+            XContentParser expectedJson = createParser(MediaTypeRegistry.JSON.xContent(), expected);
+            XContentParser actualJson = createParser(MediaTypeRegistry.JSON.xContent(), actual)
         ) {
             assertEquals(expectedJson.mapOrdered(), actualJson.mapOrdered());
         }
@@ -164,21 +165,18 @@ private static PutMappingRequest createTestItem() throws IOException {
 
     public void testResolveIndicesWithWriteIndexOnlyAndDataStreamsAndWriteAliases() {
         String[] dataStreamNames = { "foo", "bar", "baz" };
-        List<Tuple<String, Integer>> dsMetadata = org.opensearch.common.collect.List.of(
+        List<Tuple<String, Integer>> dsMetadata = List.of(
             tuple(dataStreamNames[0], randomIntBetween(1, 3)),
             tuple(dataStreamNames[1], randomIntBetween(1, 3)),
             tuple(dataStreamNames[2], randomIntBetween(1, 3))
         );
 
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dsMetadata,
-            org.opensearch.common.collect.List.of("index1", "index2", "index3")
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dsMetadata, List.of("index1", "index2", "index3"));
         cs = addAliases(
             cs,
-            org.opensearch.common.collect.List.of(
-                tuple("alias1", org.opensearch.common.collect.List.of(tuple("index1", false), tuple("index2", true))),
-                tuple("alias2", org.opensearch.common.collect.List.of(tuple("index2", false), tuple("index3", true)))
+            List.of(
+                tuple("alias1", List.of(tuple("index1", false), tuple("index2", true))),
+                tuple("alias2", List.of(tuple("index2", false), tuple("index3", true)))
             )
         );
         PutMappingRequest request = new PutMappingRequest().indices("foo", "alias1", "alias2").writeIndexOnly(true);
@@ -195,21 +193,18 @@ public void testResolveIndicesWithWriteIndexOnlyAndDataStreamsAndWriteAliases()
 
     public void testResolveIndicesWithoutWriteIndexOnlyAndDataStreamsAndWriteAliases() {
         String[] dataStreamNames = { "foo", "bar", "baz" };
-        List<Tuple<String, Integer>> dsMetadata = org.opensearch.common.collect.List.of(
+        List<Tuple<String, Integer>> dsMetadata = List.of(
             tuple(dataStreamNames[0], randomIntBetween(1, 3)),
             tuple(dataStreamNames[1], randomIntBetween(1, 3)),
             tuple(dataStreamNames[2], randomIntBetween(1, 3))
         );
 
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dsMetadata,
-            org.opensearch.common.collect.List.of("index1", "index2", "index3")
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dsMetadata, List.of("index1", "index2", "index3"));
         cs = addAliases(
             cs,
-            org.opensearch.common.collect.List.of(
-                tuple("alias1", org.opensearch.common.collect.List.of(tuple("index1", false), tuple("index2", true))),
-                tuple("alias2", org.opensearch.common.collect.List.of(tuple("index2", false), tuple("index3", true)))
+            List.of(
+                tuple("alias1", List.of(tuple("index1", false), tuple("index2", true))),
+                tuple("alias2", List.of(tuple("index2", false), tuple("index3", true)))
             )
         );
         PutMappingRequest request = new PutMappingRequest().indices("foo", "alias1", "alias2");
@@ -221,28 +216,25 @@ public void testResolveIndicesWithoutWriteIndexOnlyAndDataStreamsAndWriteAliases
         List<String> indexNames = Arrays.stream(indices).map(Index::getName).collect(Collectors.toList());
         IndexAbstraction expectedDs = cs.metadata().getIndicesLookup().get("foo");
         List<String> expectedIndices = expectedDs.getIndices().stream().map(im -> im.getIndex().getName()).collect(Collectors.toList());
-        expectedIndices.addAll(org.opensearch.common.collect.List.of("index1", "index2", "index3"));
+        expectedIndices.addAll(List.of("index1", "index2", "index3"));
         // should resolve the data stream and each alias to _all_ their respective indices
         assertThat(indexNames, containsInAnyOrder(expectedIndices.toArray()));
     }
 
     public void testResolveIndicesWithWriteIndexOnlyAndDataStreamAndIndex() {
         String[] dataStreamNames = { "foo", "bar", "baz" };
-        List<Tuple<String, Integer>> dsMetadata = org.opensearch.common.collect.List.of(
+        List<Tuple<String, Integer>> dsMetadata = List.of(
             tuple(dataStreamNames[0], randomIntBetween(1, 3)),
             tuple(dataStreamNames[1], randomIntBetween(1, 3)),
             tuple(dataStreamNames[2], randomIntBetween(1, 3))
         );
 
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dsMetadata,
-            org.opensearch.common.collect.List.of("index1", "index2", "index3")
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dsMetadata, List.of("index1", "index2", "index3"));
         cs = addAliases(
             cs,
-            org.opensearch.common.collect.List.of(
-                tuple("alias1", org.opensearch.common.collect.List.of(tuple("index1", false), tuple("index2", true))),
-                tuple("alias2", org.opensearch.common.collect.List.of(tuple("index2", false), tuple("index3", true)))
+            List.of(
+                tuple("alias1", List.of(tuple("index1", false), tuple("index2", true))),
+                tuple("alias2", List.of(tuple("index2", false), tuple("index3", true)))
             )
         );
         PutMappingRequest request = new PutMappingRequest().indices("foo", "index3").writeIndexOnly(true);
@@ -254,28 +246,25 @@ public void testResolveIndicesWithWriteIndexOnlyAndDataStreamAndIndex() {
         List<String> indexNames = Arrays.stream(indices).map(Index::getName).collect(Collectors.toList());
         IndexAbstraction expectedDs = cs.metadata().getIndicesLookup().get("foo");
         List<String> expectedIndices = expectedDs.getIndices().stream().map(im -> im.getIndex().getName()).collect(Collectors.toList());
-        expectedIndices.addAll(org.opensearch.common.collect.List.of("index1", "index2", "index3"));
+        expectedIndices.addAll(List.of("index1", "index2", "index3"));
         // should resolve the data stream and each alias to _all_ their respective indices
         assertThat(indexNames, containsInAnyOrder(expectedDs.getWriteIndex().getIndex().getName(), "index3"));
     }
 
     public void testResolveIndicesWithWriteIndexOnlyAndNoSingleWriteIndex() {
         String[] dataStreamNames = { "foo", "bar", "baz" };
-        List<Tuple<String, Integer>> dsMetadata = org.opensearch.common.collect.List.of(
+        List<Tuple<String, Integer>> dsMetadata = List.of(
             tuple(dataStreamNames[0], randomIntBetween(1, 3)),
             tuple(dataStreamNames[1], randomIntBetween(1, 3)),
             tuple(dataStreamNames[2], randomIntBetween(1, 3))
         );
 
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dsMetadata,
-            org.opensearch.common.collect.List.of("index1", "index2", "index3")
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dsMetadata, List.of("index1", "index2", "index3"));
         final ClusterState cs2 = addAliases(
             cs,
-            org.opensearch.common.collect.List.of(
-                tuple("alias1", org.opensearch.common.collect.List.of(tuple("index1", false), tuple("index2", true))),
-                tuple("alias2", org.opensearch.common.collect.List.of(tuple("index2", false), tuple("index3", true)))
+            List.of(
+                tuple("alias1", List.of(tuple("index1", false), tuple("index2", true))),
+                tuple("alias2", List.of(tuple("index2", false), tuple("index3", true)))
             )
         );
         PutMappingRequest request = new PutMappingRequest().indices("*").writeIndexOnly(true);
@@ -288,21 +277,18 @@ public void testResolveIndicesWithWriteIndexOnlyAndNoSingleWriteIndex() {
 
     public void testResolveIndicesWithWriteIndexOnlyAndAliasWithoutWriteIndex() {
         String[] dataStreamNames = { "foo", "bar", "baz" };
-        List<Tuple<String, Integer>> dsMetadata = org.opensearch.common.collect.List.of(
+        List<Tuple<String, Integer>> dsMetadata = List.of(
             tuple(dataStreamNames[0], randomIntBetween(1, 3)),
             tuple(dataStreamNames[1], randomIntBetween(1, 3)),
             tuple(dataStreamNames[2], randomIntBetween(1, 3))
         );
 
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dsMetadata,
-            org.opensearch.common.collect.List.of("index1", "index2", "index3")
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dsMetadata, List.of("index1", "index2", "index3"));
         final ClusterState cs2 = addAliases(
             cs,
-            org.opensearch.common.collect.List.of(
-                tuple("alias1", org.opensearch.common.collect.List.of(tuple("index1", false), tuple("index2", false))),
-                tuple("alias2", org.opensearch.common.collect.List.of(tuple("index2", false), tuple("index3", false)))
+            List.of(
+                tuple("alias1", List.of(tuple("index1", false), tuple("index2", false))),
+                tuple("alias2", List.of(tuple("index2", false), tuple("index3", false)))
             )
         );
         PutMappingRequest request = new PutMappingRequest().indices("alias2").writeIndexOnly(true);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexRequestTests.java
new file mode 100644
index 0000000000000..a02aa2932c24a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexRequestTests.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.open;
+
+import org.opensearch.action.support.ActiveShardCount;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class OpenIndexRequestTests extends OpenSearchTestCase {
+
+    public void testSerialization() throws IOException {
+        OpenIndexRequest request = randomRequest();
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+
+            final OpenIndexRequest deserializedRequest;
+            try (StreamInput in = out.bytes().streamInput()) {
+                deserializedRequest = new OpenIndexRequest(in);
+            }
+            assertEquals(request.timeout(), deserializedRequest.timeout());
+            assertEquals(request.clusterManagerNodeTimeout(), deserializedRequest.clusterManagerNodeTimeout());
+            assertEquals(request.indicesOptions(), deserializedRequest.indicesOptions());
+            assertEquals(request.getParentTask(), deserializedRequest.getParentTask());
+            assertEquals(request.waitForActiveShards(), deserializedRequest.waitForActiveShards());
+            assertArrayEquals(request.indices(), deserializedRequest.indices());
+        }
+    }
+
+    public void testGetDescription() {
+        String indexName = randomAlphaOfLengthBetween(3, 10);
+        OpenIndexRequest request = new OpenIndexRequest(indexName);
+        assertEquals("open indices [" + indexName + "]", request.getDescription());
+    }
+
+    private OpenIndexRequest randomRequest() {
+        OpenIndexRequest request = new OpenIndexRequest();
+        request.indices(generateRandomStringArray(10, 5, false, false));
+        if (randomBoolean()) {
+            request.indicesOptions(
+                IndicesOptions.fromOptions(randomBoolean(), randomBoolean(), randomBoolean(), randomBoolean(), randomBoolean())
+            );
+        }
+        if (randomBoolean()) {
+            request.timeout(randomPositiveTimeValue());
+        }
+        if (randomBoolean()) {
+            request.clusterManagerNodeTimeout(randomPositiveTimeValue());
+        }
+        if (randomBoolean()) {
+            request.setParentTask(randomAlphaOfLength(5), randomNonNegativeLong());
+        }
+        if (randomBoolean()) {
+            request.waitForActiveShards(
+                randomFrom(ActiveShardCount.DEFAULT, ActiveShardCount.NONE, ActiveShardCount.ONE, ActiveShardCount.ALL)
+            );
+        }
+        return request;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexResponseTests.java
index cfc82fae2837c..0c0b30515f429 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/open/OpenIndexResponseTests.java
@@ -32,12 +32,18 @@
 
 package org.opensearch.action.admin.indices.open;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 public class OpenIndexResponseTests extends AbstractSerializingTestCase<OpenIndexResponse> {
 
+    public void testToString() {
+        OpenIndexResponse response = new OpenIndexResponse(true, false);
+        String output = response.toString();
+        assertEquals("OpenIndexResponse[acknowledged=true,shards_acknowledged=false]", output);
+    }
+
     @Override
     protected OpenIndexResponse doParseInstance(XContentParser parser) {
         return OpenIndexResponse.fromXContent(parser);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockActionTests.java
new file mode 100644
index 0000000000000..8c4a6c023f9a5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/readonly/TransportVerifyShardIndexBlockActionTests.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.readonly;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TransportVerifyShardIndexBlockActionTests extends OpenSearchTestCase {
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        TransportVerifyShardIndexBlockAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        TransportVerifyShardIndexBlockAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportVerifyShardIndexBlockAction createAction() {
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        return new TransportVerifyShardIndexBlockAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            clusterService,
+            mock(IndicesService.class),
+            mock(ThreadPool.class),
+            mock(ShardStateAction.class),
+            mock(ActionFilters.class)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/refresh/RefreshResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/refresh/RefreshResponseTests.java
index 5488a266d7ac9..42d4a3d990da1 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/refresh/RefreshResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/refresh/RefreshResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.indices.refresh;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractBroadcastResponseTestCase;
 
 import java.util.List;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshActionTests.java
new file mode 100644
index 0000000000000..b2eee904bad38
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/admin/indices/refresh/TransportShardRefreshActionTests.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.admin.indices.refresh;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TransportShardRefreshActionTests extends OpenSearchTestCase {
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        TransportShardRefreshAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        TransportShardRefreshAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportShardRefreshAction createAction() {
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        return new TransportShardRefreshAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            clusterService,
+            mock(IndicesService.class),
+            mock(ThreadPool.class),
+            mock(ShardStateAction.class),
+            mock(ActionFilters.class)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexRequestTests.java
index 22586514d2c73..a287e474cfc4a 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexRequestTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction.Request;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 public class ResolveIndexRequestTests extends AbstractWireSerializingTestCase<Request> {
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexResponseTests.java
index 9588e1272577d..d230c1e04ede0 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexResponseTests.java
@@ -36,10 +36,10 @@
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction.ResolvedDataStream;
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction.ResolvedIndex;
 import org.opensearch.action.admin.indices.resolve.ResolveIndexAction.Response;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -92,9 +92,7 @@ protected Response createTestInstance() {
     private static ResolvedIndex createTestResolvedIndexInstance() {
         String name = randomAlphaOfLength(6);
         String[] aliases = randomStringArray(0, 5);
-        String[] attributes = randomSubsetOf(org.opensearch.common.collect.List.of("open", "hidden", "frozen")).toArray(
-            Strings.EMPTY_ARRAY
-        );
+        String[] attributes = randomSubsetOf(List.of("open", "hidden", "frozen")).toArray(Strings.EMPTY_ARRAY);
         String dataStream = randomBoolean() ? randomAlphaOfLength(6) : null;
 
         return new ResolvedIndex(name, aliases, attributes, dataStream);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexTests.java b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexTests.java
index 0ad31fec57472..8fbe46be856ba 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/resolve/ResolveIndexTests.java
@@ -45,10 +45,10 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.time.Clock;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/rollover/ConditionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/rollover/ConditionTests.java
index db61cac534f89..3d32d2e8365e7 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/rollover/ConditionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/rollover/ConditionTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.action.admin.indices.rollover;
 
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverServiceTests.java b/server/src/test/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverServiceTests.java
index 6265bcab82966..3cc8adf887a63 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverServiceTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/rollover/MetadataRolloverServiceTests.java
@@ -57,9 +57,9 @@
 import org.opensearch.cluster.metadata.MetadataIndexAliasesService;
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.IndexScopedSettings;
@@ -67,8 +67,8 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.ContentPath;
 import org.opensearch.index.mapper.DateFieldMapper;
@@ -110,10 +110,10 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.mockito.AdditionalAnswers.returnsFirstArg;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
@@ -125,7 +125,13 @@ public void testRolloverAliasActions() {
         String sourceIndex = randomAlphaOfLength(10);
         String targetIndex = randomAlphaOfLength(10);
 
-        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(sourceIndex, targetIndex, false, null, sourceAlias);
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            false,
+            createDefaultAliasMetadata(sourceAlias, null),
+            sourceAlias
+        );
         assertThat(actions, hasSize(2));
         boolean foundAdd = false;
         boolean foundRemove = false;
@@ -148,7 +154,13 @@ public void testRolloverAliasActionsWithExplicitWriteIndex() {
         String sourceAlias = randomAlphaOfLength(10);
         String sourceIndex = randomAlphaOfLength(10);
         String targetIndex = randomAlphaOfLength(10);
-        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(sourceIndex, targetIndex, true, null, sourceAlias);
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            true,
+            createDefaultAliasMetadata(sourceAlias, null),
+            sourceAlias
+        );
 
         assertThat(actions, hasSize(2));
         boolean foundAddWrite = false;
@@ -171,11 +183,64 @@ public void testRolloverAliasActionsWithExplicitWriteIndex() {
         assertTrue(foundRemoveWrite);
     }
 
+    public void testRolloverAliasActionsWithFilterAndExplicitWriteIndex() {
+        String sourceAlias = randomAlphaOfLength(10);
+        String sourceIndex = randomAlphaOfLength(10);
+        String targetIndex = randomAlphaOfLength(10);
+        String indexRouting = randomAlphaOfLength(10);
+        String sourceRouting = randomAlphaOfLength(10);
+        AliasMetadata aliasMetadata = createAliasMetadata(
+            sourceAlias,
+            Collections.singletonMap(randomAlphaOfLength(2), randomAlphaOfLength(2)),
+            indexRouting,
+            sourceRouting,
+            true
+        );
+
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            true,
+            aliasMetadata,
+            sourceAlias
+        );
+
+        assertThat(actions, hasSize(2));
+        boolean foundAddWrite = false;
+        boolean foundRemoveWrite = false;
+        for (AliasAction action : actions) {
+            AliasAction.Add addAction = (AliasAction.Add) action;
+            if (action.getIndex().equals(targetIndex)) {
+                assertEquals(sourceAlias, addAction.getAlias());
+                assertEquals(aliasMetadata.filter().string(), addAction.getFilter());
+                assertEquals(indexRouting, addAction.getIndexRouting());
+                assertEquals(sourceRouting, addAction.getSearchRouting());
+
+                assertTrue(addAction.writeIndex());
+                foundAddWrite = true;
+            } else if (action.getIndex().equals(sourceIndex)) {
+                assertEquals(sourceAlias, addAction.getAlias());
+                assertFalse(addAction.writeIndex());
+                foundRemoveWrite = true;
+            } else {
+                throw new AssertionError("Unknown index [" + action.getIndex() + "]");
+            }
+        }
+        assertTrue(foundAddWrite);
+        assertTrue(foundRemoveWrite);
+    }
+
     public void testRolloverAliasActionsWithHiddenAliasAndExplicitWriteIndex() {
         String sourceAlias = randomAlphaOfLength(10);
         String sourceIndex = randomAlphaOfLength(10);
         String targetIndex = randomAlphaOfLength(10);
-        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(sourceIndex, targetIndex, true, true, sourceAlias);
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            true,
+            createDefaultAliasMetadata(sourceAlias, true),
+            sourceAlias
+        );
 
         assertThat(actions, hasSize(2));
         boolean foundAddWrite = false;
@@ -201,11 +266,66 @@ public void testRolloverAliasActionsWithHiddenAliasAndExplicitWriteIndex() {
         assertTrue(foundRemoveWrite);
     }
 
+    public void testRolloverAliasActionsWithFilterAndHiddenAliasAndImplicitWriteIndex() {
+        String sourceAlias = randomAlphaOfLength(10);
+        String sourceIndex = randomAlphaOfLength(10);
+        String targetIndex = randomAlphaOfLength(10);
+        String indexRouting = randomAlphaOfLength(10);
+        String sourceRouting = randomAlphaOfLength(10);
+        AliasMetadata aliasMetadata = createAliasMetadata(
+            sourceAlias,
+            Collections.singletonMap(randomAlphaOfLength(2), randomAlphaOfLength(2)),
+            indexRouting,
+            sourceRouting,
+            true
+        );
+
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            false,
+            aliasMetadata,
+            sourceAlias
+        );
+
+        assertThat(actions, hasSize(2));
+        boolean foundAddWrite = false;
+        boolean foundRemoveWrite = false;
+        for (AliasAction action : actions) {
+            if (action.getIndex().equals(targetIndex)) {
+                assertThat(action, instanceOf(AliasAction.Add.class));
+                AliasAction.Add addAction = (AliasAction.Add) action;
+                assertEquals(sourceAlias, addAction.getAlias());
+                assertThat(addAction.writeIndex(), nullValue());
+                assertTrue(addAction.isHidden());
+                assertEquals(aliasMetadata.filter().string(), addAction.getFilter());
+                assertEquals(indexRouting, addAction.getIndexRouting());
+                assertEquals(sourceRouting, addAction.getSearchRouting());
+                foundAddWrite = true;
+            } else if (action.getIndex().equals(sourceIndex)) {
+                assertThat(action, instanceOf(AliasAction.Remove.class));
+                AliasAction.Remove removeAction = (AliasAction.Remove) action;
+                assertEquals(sourceAlias, removeAction.getAlias());
+                foundRemoveWrite = true;
+            } else {
+                throw new AssertionError("Unknown index [" + action.getIndex() + "]");
+            }
+        }
+        assertTrue(foundAddWrite);
+        assertTrue(foundRemoveWrite);
+    }
+
     public void testRolloverAliasActionsWithHiddenAliasAndImplicitWriteIndex() {
         String sourceAlias = randomAlphaOfLength(10);
         String sourceIndex = randomAlphaOfLength(10);
         String targetIndex = randomAlphaOfLength(10);
-        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(sourceIndex, targetIndex, false, true, sourceAlias);
+        List<AliasAction> actions = MetadataRolloverService.rolloverAliasToNewIndex(
+            sourceIndex,
+            targetIndex,
+            false,
+            createDefaultAliasMetadata(sourceAlias, true),
+            sourceAlias
+        );
 
         assertThat(actions, hasSize(2));
         boolean foundAddWrite = false;
@@ -305,7 +425,7 @@ public void testDataStreamValidation() throws IOException {
             equalTo("aliases, mappings, and index settings may not be specified when rolling over a data stream")
         );
 
-        String mapping = Strings.toString(JsonXContent.contentBuilder().startObject().startObject("_doc").endObject().endObject());
+        String mapping = JsonXContent.contentBuilder().startObject().startObject("_doc").endObject().endObject().toString();
         CreateIndexRequest mappingReq = new CreateIndexRequest().mapping(mapping);
         exception = expectThrows(
             IllegalArgumentException.class,
@@ -603,7 +723,8 @@ public void testRolloverClusterState() throws Exception {
             IndexNameExpressionResolver mockIndexNameExpressionResolver = mock(IndexNameExpressionResolver.class);
             when(mockIndexNameExpressionResolver.resolveDateMathExpression(any())).then(returnsFirstArg());
 
-            ShardLimitValidator shardLimitValidator = new ShardLimitValidator(Settings.EMPTY, clusterService);
+            final SystemIndices systemIndices = new SystemIndices(emptyMap());
+            ShardLimitValidator shardLimitValidator = new ShardLimitValidator(Settings.EMPTY, clusterService, systemIndices);
             MetadataCreateIndexService createIndexService = new MetadataCreateIndexService(
                 Settings.EMPTY,
                 clusterService,
@@ -615,8 +736,9 @@ public void testRolloverClusterState() throws Exception {
                 IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
                 testThreadPool,
                 null,
-                new SystemIndices(emptyMap()),
-                false
+                systemIndices,
+                false,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
             );
             MetadataIndexAliasesService indexAliasesService = new MetadataIndexAliasesService(
                 clusterService,
@@ -739,7 +861,8 @@ public void testRolloverClusterStateForDataStream() throws Exception {
             IndexNameExpressionResolver mockIndexNameExpressionResolver = mock(IndexNameExpressionResolver.class);
             when(mockIndexNameExpressionResolver.resolveDateMathExpression(any())).then(returnsFirstArg());
 
-            ShardLimitValidator shardLimitValidator = new ShardLimitValidator(Settings.EMPTY, clusterService);
+            final SystemIndices systemIndices = new SystemIndices(emptyMap());
+            ShardLimitValidator shardLimitValidator = new ShardLimitValidator(Settings.EMPTY, clusterService, systemIndices);
             MetadataCreateIndexService createIndexService = new MetadataCreateIndexService(
                 Settings.EMPTY,
                 clusterService,
@@ -751,8 +874,9 @@ public void testRolloverClusterStateForDataStream() throws Exception {
                 IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
                 testThreadPool,
                 null,
-                new SystemIndices(emptyMap()),
-                false
+                systemIndices,
+                false,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
             );
             MetadataIndexAliasesService indexAliasesService = new MetadataIndexAliasesService(
                 clusterService,
@@ -929,7 +1053,8 @@ public void testRolloverClusterStateForDataStreamNoTemplate() throws Exception {
             testThreadPool,
             null,
             new SystemIndices(emptyMap()),
-            false
+            false,
+            new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
         );
         MetadataIndexAliasesService indexAliasesService = new MetadataIndexAliasesService(
             clusterService,
@@ -1004,4 +1129,23 @@ private static IndexMetadata createMetadata(String indexName) {
             .settings(settings)
             .build();
     }
+
+    private static AliasMetadata createDefaultAliasMetadata(String alias, Boolean isHidden) {
+        return AliasMetadata.builder(alias).isHidden(isHidden).build();
+    }
+
+    private static AliasMetadata createAliasMetadata(
+        String alias,
+        Map filter,
+        String indexRouting,
+        String searchRouting,
+        Boolean isHidden
+    ) {
+        return AliasMetadata.builder(alias)
+            .isHidden(isHidden)
+            .filter(filter)
+            .indexRouting(indexRouting)
+            .searchRouting(searchRouting)
+            .build();
+    }
 }
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverRequestTests.java
index 079e5d388bbf4..9ded3e704a5bc 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverRequestTests.java
@@ -34,28 +34,29 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParseException;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.XContentTestUtils;
+import org.junit.Before;
 
 import java.io.IOException;
-import org.junit.Before;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -147,7 +148,7 @@ public void testTypelessMappingParsing() throws Exception {
         String mapping = createIndexRequest.mappings();
         assertNotNull(mapping);
 
-        Map<String, Object> parsedMapping = XContentHelper.convertToMap(new BytesArray(mapping), false, XContentType.JSON).v2();
+        Map<String, Object> parsedMapping = XContentHelper.convertToMap(new BytesArray(mapping), false, MediaTypeRegistry.JSON).v2();
 
         @SuppressWarnings("unchecked")
         Map<String, Object> properties = (Map<String, Object>) parsedMapping.get(MapperService.SINGLE_MAPPING_NAME);
@@ -180,7 +181,7 @@ public void testSerialize() throws Exception {
     public void testUnknownFields() throws IOException {
         final RolloverRequest request = new RolloverRequest();
         XContentType xContentType = randomFrom(XContentType.values());
-        final XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+        final XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType);
         builder.startObject();
         {
             builder.startObject("conditions");
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverResponseTests.java
index 61ab9853266b1..8f0d508f23ead 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/rollover/RolloverResponseTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.admin.indices.rollover;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/rollover/TransportRolloverActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/rollover/TransportRolloverActionTests.java
index 8ef8de81041e3..d3167a6a426ff 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/rollover/TransportRolloverActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/rollover/TransportRolloverActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.admin.indices.rollover;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.admin.indices.stats.CommonStats;
 import org.opensearch.action.admin.indices.stats.IndexStats;
@@ -59,10 +58,12 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.cache.query.QueryCacheStats;
 import org.opensearch.index.cache.request.RequestCacheStats;
 import org.opensearch.index.engine.SegmentsStats;
@@ -74,7 +75,6 @@
 import org.opensearch.index.search.stats.SearchStats;
 import org.opensearch.index.shard.DocsStats;
 import org.opensearch.index.shard.IndexingStats;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.StoreStats;
 import org.opensearch.index.warmer.WarmerStats;
@@ -83,7 +83,6 @@
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
-import org.mockito.ArgumentCaptor;
 
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -92,14 +91,16 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.mockito.ArgumentCaptor;
+
 import static java.util.Collections.emptyList;
 import static org.opensearch.action.admin.indices.rollover.TransportRolloverAction.evaluateConditions;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyBoolean;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -298,7 +299,7 @@ public void testConditionEvaluationWhenAliasToWriteAndReadIndicesConsidersOnlyPr
         RolloverRequest rolloverRequest = new RolloverRequest("logs-alias", "logs-index-000003");
         rolloverRequest.addMaxIndexDocsCondition(500L);
         rolloverRequest.dryRun(true);
-        transportRolloverAction.masterOperation(mock(Task.class), rolloverRequest, stateBefore, future);
+        transportRolloverAction.clusterManagerOperation(mock(Task.class), rolloverRequest, stateBefore, future);
 
         RolloverResponse response = future.actionGet();
         assertThat(response.getOldIndex(), equalTo("logs-index-000002"));
@@ -314,7 +315,7 @@ public void testConditionEvaluationWhenAliasToWriteAndReadIndicesConsidersOnlyPr
         rolloverRequest = new RolloverRequest("logs-alias", "logs-index-000003");
         rolloverRequest.addMaxIndexDocsCondition(300L);
         rolloverRequest.dryRun(true);
-        transportRolloverAction.masterOperation(mock(Task.class), rolloverRequest, stateBefore, future);
+        transportRolloverAction.clusterManagerOperation(mock(Task.class), rolloverRequest, stateBefore, future);
 
         response = future.actionGet();
         assertThat(response.getOldIndex(), equalTo("logs-index-000002"));
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponseTests.java
index eb4a89e609509..b90be87e3a600 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentResponseTests.java
@@ -37,8 +37,8 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.Segment;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestTests.java
index 402d6439c4838..d35c821b41aa0 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/segments/IndicesSegmentsRequestTests.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.junit.Before;
 
 import java.util.Collection;
@@ -56,7 +56,7 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     public void setupIndex() {
         Settings settings = Settings.builder()
             // don't allow any merges so that the num docs is the expected segments
-            .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+            .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
             .build();
         createIndex("test", settings);
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsActionTests.java
index cefb59c40949c..f2b6688716e70 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.admin.indices.settings.get;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.replication.ClusterStateCreationUtils;
@@ -44,7 +43,9 @@
 import org.opensearch.common.settings.SettingsFilter;
 import org.opensearch.common.settings.SettingsModule;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -84,9 +85,13 @@ class TestTransportGetSettingsAction extends TransportGetSettingsAction {
         }
 
         @Override
-        protected void masterOperation(GetSettingsRequest request, ClusterState state, ActionListener<GetSettingsResponse> listener) {
+        protected void clusterManagerOperation(
+            GetSettingsRequest request,
+            ClusterState state,
+            ActionListener<GetSettingsResponse> listener
+        ) {
             ClusterState stateWithIndex = ClusterStateCreationUtils.state(indexName, 1, 1);
-            super.masterOperation(request, stateWithIndex, listener);
+            super.clusterManagerOperation(request, stateWithIndex, listener);
         }
     }
 
@@ -104,7 +109,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestTests.java
index 0484f710cda34..f3d3b6cff4b06 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsRequestTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.action.admin.indices.settings.get;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponseTests.java
index aada9779b6f17..a596f1f76d190 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/settings/get/GetSettingsResponseTests.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.action.admin.indices.settings.get;
 
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
 
@@ -72,9 +73,7 @@ protected GetSettingsResponse createTestInstance() {
             builder.put("index.refresh_interval", "1s");
             indexToSettings.put(indexName, builder.build());
         }
-        ImmutableOpenMap<String, Settings> immutableIndexToSettings = ImmutableOpenMap.<String, Settings>builder()
-            .putAll(indexToSettings)
-            .build();
+        final Map<String, Settings> immutableIndexToSettings = Collections.unmodifiableMap(indexToSettings);
 
         if (randomBoolean()) {
             for (String indexName : indexToSettings.keySet()) {
@@ -83,9 +82,7 @@ protected GetSettingsResponse createTestInstance() {
             }
         }
 
-        ImmutableOpenMap<String, Settings> immutableIndexToDefaultSettings = ImmutableOpenMap.<String, Settings>builder()
-            .putAll(indexToDefaultSettings)
-            .build();
+        final Map<String, Settings> immutableIndexToDefaultSettings = Collections.unmodifiableMap(indexToDefaultSettings);
 
         return new GetSettingsResponse(immutableIndexToSettings, immutableIndexToDefaultSettings);
     }
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestSerializationTests.java b/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestSerializationTests.java
index 5b7f5b82bfa6c..1b859923b7e22 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestSerializationTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestSerializationTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.action.admin.indices.settings.put;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -56,7 +56,9 @@ protected UpdateSettingsRequest mutateInstance(UpdateSettingsRequest request) {
         UpdateSettingsRequest mutation = copyRequest(request);
         List<Runnable> mutators = new ArrayList<>();
         Supplier<TimeValue> timeValueSupplier = () -> TimeValue.parseTimeValue(OpenSearchTestCase.randomTimeValue(), "_setting");
-        mutators.add(() -> mutation.masterNodeTimeout(randomValueOtherThan(request.masterNodeTimeout(), timeValueSupplier)));
+        mutators.add(
+            () -> mutation.clusterManagerNodeTimeout(randomValueOtherThan(request.clusterManagerNodeTimeout(), timeValueSupplier))
+        );
         mutators.add(() -> mutation.timeout(randomValueOtherThan(request.timeout(), timeValueSupplier)));
         mutators.add(() -> mutation.settings(mutateSettings(request.settings())));
         mutators.add(() -> mutation.indices(mutateIndices(request.indices())));
@@ -87,7 +89,7 @@ public static UpdateSettingsRequest createTestItem() {
         UpdateSettingsRequest request = randomBoolean()
             ? new UpdateSettingsRequest(randomSettings(0, 2))
             : new UpdateSettingsRequest(randomSettings(0, 2), randomIndicesNames(0, 2));
-        request.masterNodeTimeout(randomTimeValue());
+        request.clusterManagerNodeTimeout(randomTimeValue());
         request.timeout(randomTimeValue());
         request.indicesOptions(IndicesOptions.fromOptions(randomBoolean(), randomBoolean(), randomBoolean(), randomBoolean()));
         request.setPreserveExisting(randomBoolean());
@@ -96,7 +98,7 @@ public static UpdateSettingsRequest createTestItem() {
 
     private static UpdateSettingsRequest copyRequest(UpdateSettingsRequest request) {
         UpdateSettingsRequest result = new UpdateSettingsRequest(request.settings(), request.indices());
-        result.masterNodeTimeout(request.masterNodeTimeout());
+        result.clusterManagerNodeTimeout(request.clusterManagerNodeTimeout());
         result.timeout(request.timeout());
         result.indicesOptions(request.indicesOptions());
         result.setPreserveExisting(request.isPreserveExisting());
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestTests.java
index 062f0b64c73a4..0712ad1a9b313 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/settings/put/UpdateSettingsRequestTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.indices.settings.put;
 
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreResponseTests.java
index 67eb8c9e9bdd9..eb2089febd8a1 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/shards/IndicesShardStoreResponseTests.java
@@ -36,20 +36,19 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.NodeDisconnectedException;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -59,11 +58,10 @@
 
 public class IndicesShardStoreResponseTests extends OpenSearchTestCase {
     public void testBasicSerialization() throws Exception {
-        ImmutableOpenMap.Builder<String, ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>>> indexStoreStatuses =
-            ImmutableOpenMap.builder();
+        final Map<String, Map<Integer, List<IndicesShardStoresResponse.StoreStatus>>> indexStoreStatuses = new HashMap<>();
 
         List<IndicesShardStoresResponse.Failure> failures = new ArrayList<>();
-        ImmutableOpenIntMap.Builder<List<IndicesShardStoresResponse.StoreStatus>> storeStatuses = ImmutableOpenIntMap.builder();
+        final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> storeStatuses = new HashMap<>();
 
         DiscoveryNode node1 = new DiscoveryNode("node1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         DiscoveryNode node2 = new DiscoveryNode("node2", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
@@ -89,14 +87,14 @@ public void testBasicSerialization() throws Exception {
         );
         storeStatuses.put(0, storeStatusList);
         storeStatuses.put(1, storeStatusList);
-        ImmutableOpenIntMap<List<IndicesShardStoresResponse.StoreStatus>> storesMap = storeStatuses.build();
+        final Map<Integer, List<IndicesShardStoresResponse.StoreStatus>> storesMap = Collections.unmodifiableMap(storeStatuses);
         indexStoreStatuses.put("test", storesMap);
         indexStoreStatuses.put("test2", storesMap);
 
         failures.add(new IndicesShardStoresResponse.Failure("node1", "test", 3, new NodeDisconnectedException(node1, "")));
 
         IndicesShardStoresResponse storesResponse = new IndicesShardStoresResponse(
-            indexStoreStatuses.build(),
+            indexStoreStatuses,
             Collections.unmodifiableList(failures)
         );
         XContentBuilder contentBuilder = XContentFactory.jsonBuilder();
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeRequestTests.java
index b4c211b34c644..6d83bebe4b994 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeRequestTests.java
@@ -32,14 +32,17 @@
 
 package org.opensearch.action.admin.indices.shrink;
 
+import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestTests;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.RandomCreateIndexGenerator;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
@@ -49,7 +52,7 @@
 import java.util.function.Supplier;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
-import static org.opensearch.common.xcontent.ToXContent.EMPTY_PARAMS;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.hasToString;
 
@@ -76,7 +79,7 @@ private void runTestCopySettingsValidation(final Boolean copySettings, final Con
     public void testToXContent() throws IOException {
         {
             ResizeRequest request = new ResizeRequest("target", "source");
-            String actualRequestBody = Strings.toString(request);
+            String actualRequestBody = Strings.toString(MediaTypeRegistry.JSON, request);
             assertEquals("{\"settings\":{},\"aliases\":{}}", actualRequestBody);
         }
         {
@@ -91,7 +94,7 @@ public void testToXContent() throws IOException {
             settings.put(SETTING_NUMBER_OF_SHARDS, 10);
             target.settings(settings);
             request.setTargetIndex(target);
-            String actualRequestBody = Strings.toString(request);
+            String actualRequestBody = Strings.toString(MediaTypeRegistry.JSON, request);
             String expectedRequestBody = "{\"settings\":{\"index\":{\"number_of_shards\":\"10\"}},"
                 + "\"aliases\":{\"test_alias\":{\"filter\":{\"term\":{\"year\":2016}},\"routing\":\"1\",\"is_write_index\":true}}}";
             assertEquals(expectedRequestBody, actualRequestBody);
@@ -125,6 +128,89 @@ public void testToAndFromXContent() throws IOException {
         OpenSearchAssertions.assertToXContentEquivalent(originalBytes, finalBytes, xContentType);
     }
 
+    public void testTargetIndexSettingsValidation() {
+        ResizeRequest resizeRequest = new ResizeRequest(randomAlphaOfLengthBetween(3, 10), randomAlphaOfLengthBetween(3, 10));
+        CreateIndexRequest createIndexRequest = new CreateIndexRequest(randomAlphaOfLengthBetween(3, 10));
+        createIndexRequest.settings(Settings.builder().put("index.blocks.read_only", true));
+        resizeRequest.setTargetIndex(createIndexRequest);
+        ActionRequestValidationException e = resizeRequest.validate();
+        assertEquals(
+            "Validation Failed: 1: target index ["
+                + createIndexRequest.index()
+                + "] will be blocked by [index.blocks.read_only=true],"
+                + " this will disable metadata writes and cause the shards to be unassigned;",
+            e.getMessage()
+        );
+
+        createIndexRequest.settings(Settings.builder().put("index.blocks.metadata", true));
+        resizeRequest.setMaxShardSize(new ByteSizeValue(randomIntBetween(1, 100)));
+        resizeRequest.setTargetIndex(createIndexRequest);
+        e = resizeRequest.validate();
+        assertEquals(
+            "Validation Failed: 1: target index ["
+                + createIndexRequest.index()
+                + "] will be blocked by [index.blocks.metadata=true],"
+                + " this will disable metadata writes and cause the shards to be unassigned;",
+            e.getMessage()
+        );
+
+        createIndexRequest.settings(
+            Settings.builder()
+                .put("index.sort.field", randomAlphaOfLengthBetween(3, 10))
+                .put("index.routing_partition_size", randomIntBetween(1, 10))
+        );
+        resizeRequest.setTargetIndex(createIndexRequest);
+        e = resizeRequest.validate();
+        assertEquals(
+            "Validation Failed: 1: can't override index sort when resizing an index;"
+                + "2: cannot provide a routing partition size value when resizing an index;",
+            e.getMessage()
+        );
+
+        createIndexRequest.settings(Settings.builder().put("index.number_of_shards", randomIntBetween(1, 10)));
+        resizeRequest.setMaxShardSize(new ByteSizeValue(randomIntBetween(1, 100)));
+        resizeRequest.setTargetIndex(createIndexRequest);
+        e = resizeRequest.validate();
+        assertEquals("Validation Failed: 1: Cannot set max_shard_size and index.number_of_shards at the same time!;", e.getMessage());
+
+        resizeRequest.setResizeType(ResizeType.SPLIT);
+        createIndexRequest.settings(Settings.builder().build());
+        resizeRequest.setMaxShardSize(new ByteSizeValue(randomIntBetween(1, 100)));
+        resizeRequest.setTargetIndex(createIndexRequest);
+        e = resizeRequest.validate();
+        assertEquals(
+            "Validation Failed: 1: index.number_of_shards is required for split operations;" + "2: Unsupported parameter [max_shard_size];",
+            e.getMessage()
+        );
+
+        resizeRequest.setResizeType(ResizeType.CLONE);
+        createIndexRequest.settings(Settings.builder().build());
+        resizeRequest.setMaxShardSize(new ByteSizeValue(randomIntBetween(1, 100)));
+        resizeRequest.setTargetIndex(createIndexRequest);
+        e = resizeRequest.validate();
+        assertEquals("Validation Failed: 1: Unsupported parameter [max_shard_size];", e.getMessage());
+    }
+
+    public void testGetDescription() {
+        String sourceIndexName = randomAlphaOfLengthBetween(3, 10);
+        String targetIndexName = randomAlphaOfLengthBetween(3, 10);
+        ResizeRequest request = new ResizeRequest(targetIndexName, sourceIndexName);
+        String resizeType;
+        switch (randomIntBetween(0, 2)) {
+            case 1:
+                request.setResizeType(ResizeType.SPLIT);
+                resizeType = "split";
+                break;
+            case 2:
+                request.setResizeType(ResizeType.CLONE);
+                resizeType = "clone";
+                break;
+            default:
+                resizeType = "shrink";
+        }
+        assertEquals(resizeType + " from [" + sourceIndexName + "] to [" + targetIndexName + "]", request.getDescription());
+    }
+
     private static ResizeRequest createTestItem() {
         ResizeRequest resizeRequest = new ResizeRequest(randomAlphaOfLengthBetween(3, 10), randomAlphaOfLengthBetween(3, 10));
         if (randomBoolean()) {
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeResponseTests.java
index fe60d3652ae1b..f984c969e4b70 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/shrink/ResizeResponseTests.java
@@ -32,19 +32,26 @@
 
 package org.opensearch.action.admin.indices.shrink;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 public class ResizeResponseTests extends AbstractSerializingTestCase<ResizeResponse> {
 
     public void testToXContent() {
         ResizeResponse response = new ResizeResponse(true, false, "index_name");
-        String output = Strings.toString(response);
+        String output = Strings.toString(MediaTypeRegistry.JSON, response);
         assertEquals("{\"acknowledged\":true,\"shards_acknowledged\":false,\"index\":\"index_name\"}", output);
     }
 
+    public void testToString() {
+        ResizeResponse response = new ResizeResponse(true, false, "index_name");
+        String output = response.toString();
+        assertEquals("ResizeResponse[acknowledged=true,shards_acknowledged=false,index=index_name]", output);
+    }
+
     @Override
     protected ResizeResponse doParseInstance(XContentParser parser) {
         return ResizeResponse.fromXContent(parser);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/shrink/TransportResizeActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/shrink/TransportResizeActionTests.java
index e4b79ac54f8fd..848df5f8e4979 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/shrink/TransportResizeActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/shrink/TransportResizeActionTests.java
@@ -38,8 +38,8 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
@@ -52,7 +52,9 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.MaxRetryAllocationDecider;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.shard.DocsStats;
+import org.opensearch.index.store.StoreStats;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.gateway.TestGatewayAllocator;
@@ -107,6 +109,7 @@ public void testErrorCondition() {
                     new ResizeRequest("target", "source"),
                     state,
                     (i) -> new DocsStats(Integer.MAX_VALUE, between(1, 1000), between(1, 100)),
+                    new StoreStats(between(1, 10000), between(1, 10000)),
                     "source",
                     "target"
                 )
@@ -121,6 +124,7 @@ public void testErrorCondition() {
                 req,
                 clusterState,
                 (i) -> i == 2 || i == 3 ? new DocsStats(Integer.MAX_VALUE / 2, between(1, 1000), between(1, 10000)) : null,
+                new StoreStats(between(1, 10000), between(1, 10000)),
                 "source",
                 "target"
             );
@@ -139,6 +143,7 @@ public void testErrorCondition() {
                 req,
                 clusterState,
                 (i) -> new DocsStats(between(10, 1000), between(1, 10), between(1, 10000)),
+                new StoreStats(between(1, 10000), between(1, 10000)),
                 "source",
                 "target"
             );
@@ -167,6 +172,7 @@ public void testErrorCondition() {
             new ResizeRequest("target", "source"),
             clusterState,
             (i) -> new DocsStats(between(1, 1000), between(1, 1000), between(0, 10000)),
+            new StoreStats(between(1, 10000), between(1, 10000)),
             "source",
             "target"
         );
@@ -193,13 +199,27 @@ public void testPassNumRoutingShards() {
         ResizeRequest resizeRequest = new ResizeRequest("target", "source");
         resizeRequest.setResizeType(ResizeType.SPLIT);
         resizeRequest.getTargetIndexRequest().settings(Settings.builder().put("index.number_of_shards", 2).build());
-        TransportResizeAction.prepareCreateIndexRequest(resizeRequest, clusterState, null, "source", "target");
+        TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            null,
+            new StoreStats(between(1, 10000), between(1, 10000)),
+            "source",
+            "target"
+        );
 
         resizeRequest.getTargetIndexRequest()
             .settings(
                 Settings.builder().put("index.number_of_routing_shards", randomIntBetween(2, 10)).put("index.number_of_shards", 2).build()
             );
-        TransportResizeAction.prepareCreateIndexRequest(resizeRequest, clusterState, null, "source", "target");
+        TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            null,
+            new StoreStats(between(1, 10000), between(1, 10000)),
+            "source",
+            "target"
+        );
     }
 
     public void testPassNumRoutingShardsAndFail() {
@@ -224,7 +244,14 @@ public void testPassNumRoutingShardsAndFail() {
         ResizeRequest resizeRequest = new ResizeRequest("target", "source");
         resizeRequest.setResizeType(ResizeType.SPLIT);
         resizeRequest.getTargetIndexRequest().settings(Settings.builder().put("index.number_of_shards", numShards * 2).build());
-        TransportResizeAction.prepareCreateIndexRequest(resizeRequest, clusterState, null, "source", "target");
+        TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            null,
+            new StoreStats(between(1, 10000), between(1, 10000)),
+            "source",
+            "target"
+        );
 
         resizeRequest.getTargetIndexRequest()
             .settings(
@@ -233,7 +260,14 @@ public void testPassNumRoutingShardsAndFail() {
         ClusterState finalState = clusterState;
         IllegalArgumentException iae = expectThrows(
             IllegalArgumentException.class,
-            () -> TransportResizeAction.prepareCreateIndexRequest(resizeRequest, finalState, null, "source", "target")
+            () -> TransportResizeAction.prepareCreateIndexRequest(
+                resizeRequest,
+                finalState,
+                null,
+                new StoreStats(between(1, 10000), between(1, 10000)),
+                "source",
+                "target"
+            )
         );
         assertEquals("cannot provide index.number_of_routing_shards on resize", iae.getMessage());
     }
@@ -266,6 +300,7 @@ public void testShrinkIndexSettings() {
             target,
             clusterState,
             (i) -> stats,
+            new StoreStats(between(1, 10000), between(1, 10000)),
             indexName,
             "target"
         );
@@ -276,6 +311,256 @@ public void testShrinkIndexSettings() {
         assertEquals(request.waitForActiveShards(), activeShardCount);
     }
 
+    public void testShrinkWithMaxShardSize() {
+        String indexName = randomAlphaOfLength(10);
+        // create one that won't fail
+        ClusterState clusterState = ClusterState.builder(
+            createClusterState(indexName, 10, 0, Settings.builder().put("index.blocks.write", true).build())
+        ).nodes(DiscoveryNodes.builder().add(newNode("node1"))).build();
+
+        AllocationService service = new AllocationService(
+            new AllocationDeciders(Collections.singleton(new MaxRetryAllocationDecider())),
+            new TestGatewayAllocator(),
+            new BalancedShardsAllocator(Settings.EMPTY),
+            EmptyClusterInfoService.INSTANCE,
+            EmptySnapshotsInfoService.INSTANCE
+        );
+        RoutingTable routingTable = service.reroute(clusterState, "reroute").routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+        // now we start the shard
+        routingTable = OpenSearchAllocationTestCase.startInitializingShardsAndReroute(service, clusterState, indexName).routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+        int numSourceShards = clusterState.metadata().index(indexName).getNumberOfShards();
+        DocsStats stats = new DocsStats(between(0, (IndexWriter.MAX_DOCS) / numSourceShards), between(1, 1000), between(1, 10000));
+
+        // target index's shards number must be the lowest factor of the source index's shards number
+        int expectedShardsNum = 5;
+        ResizeRequest resizeRequest = new ResizeRequest("target", indexName);
+        resizeRequest.setMaxShardSize(new ByteSizeValue(25));
+        // clear index settings
+        resizeRequest.getTargetIndexRequest().settings(Settings.builder().build());
+        resizeRequest.setWaitForActiveShards(expectedShardsNum);
+        CreateIndexClusterStateUpdateRequest request = TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            (i) -> stats,
+            new StoreStats(100, between(1, 10000)),
+            indexName,
+            "target"
+        );
+        assertNotNull(request.recoverFrom());
+        assertEquals(indexName, request.recoverFrom().getName());
+        assertEquals(String.valueOf(expectedShardsNum), request.settings().get("index.number_of_shards"));
+        assertEquals("shrink_index", request.cause());
+        assertEquals(request.waitForActiveShards(), ActiveShardCount.from(expectedShardsNum));
+
+        // if max_shard_size is greater than whole of the source primary shards' storage,
+        // then the target index will only have one primary shard.
+        expectedShardsNum = 1;
+        resizeRequest.setMaxShardSize(new ByteSizeValue(1000));
+        // clear index settings
+        resizeRequest.getTargetIndexRequest().settings(Settings.builder().build());
+        resizeRequest.setWaitForActiveShards(expectedShardsNum);
+        request = TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            (i) -> stats,
+            new StoreStats(100, between(1, 10000)),
+            indexName,
+            "target"
+        );
+        assertNotNull(request.recoverFrom());
+        assertEquals(indexName, request.recoverFrom().getName());
+        assertEquals(String.valueOf(expectedShardsNum), request.settings().get("index.number_of_shards"));
+        assertEquals("shrink_index", request.cause());
+        assertEquals(request.waitForActiveShards(), ActiveShardCount.from(expectedShardsNum));
+
+        // if max_shard_size is less than the primary shard's storage of the source index,
+        // then the target index's shards number will be equal to the source index's.
+        expectedShardsNum = numSourceShards;
+        resizeRequest.setMaxShardSize(new ByteSizeValue(1));
+        // clear index settings
+        resizeRequest.getTargetIndexRequest().settings(Settings.builder().build());
+        resizeRequest.setWaitForActiveShards(expectedShardsNum);
+        request = TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            (i) -> stats,
+            new StoreStats(100, between(1, 10000)),
+            indexName,
+            "target"
+        );
+        assertNotNull(request.recoverFrom());
+        assertEquals(indexName, request.recoverFrom().getName());
+        assertEquals(String.valueOf(expectedShardsNum), request.settings().get("index.number_of_shards"));
+        assertEquals("shrink_index", request.cause());
+        assertEquals(request.waitForActiveShards(), ActiveShardCount.from(expectedShardsNum));
+    }
+
+    public void testCalculateTargetIndexShardsNum() {
+        String indexName = randomAlphaOfLength(10);
+        ClusterState clusterState = ClusterState.builder(
+            createClusterState(indexName, randomIntBetween(2, 10), 0, Settings.builder().put("index.blocks.write", true).build())
+        ).nodes(DiscoveryNodes.builder().add(newNode("node1"))).build();
+        IndexMetadata indexMetadata = clusterState.metadata().index(indexName);
+
+        assertEquals(TransportResizeAction.calculateTargetIndexShardsNum(null, new StoreStats(100, between(1, 10000)), indexMetadata), 1);
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(0),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            1
+        );
+        assertEquals(TransportResizeAction.calculateTargetIndexShardsNum(new ByteSizeValue(1), null, indexMetadata), 1);
+        assertEquals(TransportResizeAction.calculateTargetIndexShardsNum(new ByteSizeValue(1), new StoreStats(0, 0), indexMetadata), 1);
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(1000),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            1
+        );
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(1),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            indexMetadata.getNumberOfShards()
+        );
+
+        clusterState = ClusterState.builder(
+            createClusterState(indexName, 10, 0, Settings.builder().put("index.blocks.write", true).build())
+        ).nodes(DiscoveryNodes.builder().add(newNode("node1"))).build();
+        indexMetadata = clusterState.metadata().index(indexName);
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(10),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            10
+        );
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(12),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            indexMetadata.getNumberOfShards()
+        );
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(20),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            5
+        );
+        assertEquals(
+            TransportResizeAction.calculateTargetIndexShardsNum(
+                new ByteSizeValue(50),
+                new StoreStats(100, between(1, 10000)),
+                indexMetadata
+            ),
+            2
+        );
+    }
+
+    public void testIndexBlocks() {
+        String indexName = randomAlphaOfLength(10);
+        // create one that won't fail
+        ClusterState clusterState = ClusterState.builder(
+            createClusterState(indexName, 10, 0, 40, Settings.builder().put("index.blocks.read_only", true).build())
+        ).nodes(DiscoveryNodes.builder().add(newNode("node1"))).build();
+
+        // Target index will be blocked by [index.blocks.read_only=true] copied from the source index
+        ResizeRequest resizeRequest = new ResizeRequest("target", indexName);
+        ResizeType resizeType;
+        switch (randomIntBetween(0, 2)) {
+            case 0:
+                resizeType = ResizeType.SHRINK;
+                break;
+            case 1:
+                resizeType = ResizeType.SPLIT;
+                break;
+            default:
+                resizeType = ResizeType.CLONE;
+        }
+        resizeRequest.setResizeType(resizeType);
+        resizeRequest.getTargetIndexRequest().settings(Settings.builder().put("index.number_of_shards", randomIntBetween(1, 100)).build());
+        ClusterState finalState = clusterState;
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> TransportResizeAction.prepareCreateIndexRequest(
+                resizeRequest,
+                finalState,
+                null,
+                new StoreStats(between(1, 10000), between(1, 10000)),
+                indexName,
+                "target"
+            )
+        );
+        assertEquals(
+            "target index [target] will be blocked by [index.blocks.read_only=true] which is copied from the source index ["
+                + indexName
+                + "], this will disable metadata writes and cause the shards to be unassigned",
+            iae.getMessage()
+        );
+
+        // Overwrites the source index's settings index.blocks.read_only, so resize won't fail
+        AllocationService service = new AllocationService(
+            new AllocationDeciders(Collections.singleton(new MaxRetryAllocationDecider())),
+            new TestGatewayAllocator(),
+            new BalancedShardsAllocator(Settings.EMPTY),
+            EmptyClusterInfoService.INSTANCE,
+            EmptySnapshotsInfoService.INSTANCE
+        );
+        RoutingTable routingTable = service.reroute(clusterState, "reroute").routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+        // now we start the shard
+        routingTable = OpenSearchAllocationTestCase.startInitializingShardsAndReroute(service, clusterState, indexName).routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+        int numSourceShards = clusterState.metadata().index(indexName).getNumberOfShards();
+        DocsStats stats = new DocsStats(between(0, (IndexWriter.MAX_DOCS) / numSourceShards), between(1, 1000), between(1, 10000));
+
+        int expectedShardsNum;
+        String cause;
+        switch (resizeType) {
+            case SHRINK:
+                expectedShardsNum = 5;
+                cause = "shrink_index";
+                break;
+            case SPLIT:
+                expectedShardsNum = 20;
+                cause = "split_index";
+                break;
+            default:
+                expectedShardsNum = 10;
+                cause = "clone_index";
+        }
+        resizeRequest.getTargetIndexRequest()
+            .settings(Settings.builder().put("index.number_of_shards", expectedShardsNum).put("index.blocks.read_only", false).build());
+        final ActiveShardCount activeShardCount = randomBoolean() ? ActiveShardCount.ALL : ActiveShardCount.ONE;
+        resizeRequest.setWaitForActiveShards(activeShardCount);
+        CreateIndexClusterStateUpdateRequest request = TransportResizeAction.prepareCreateIndexRequest(
+            resizeRequest,
+            clusterState,
+            (i) -> stats,
+            new StoreStats(100, between(1, 10000)),
+            indexName,
+            "target"
+        );
+        assertNotNull(request.recoverFrom());
+        assertEquals(indexName, request.recoverFrom().getName());
+        assertEquals(String.valueOf(expectedShardsNum), request.settings().get("index.number_of_shards"));
+        assertEquals(cause, request.cause());
+        assertEquals(request.waitForActiveShards(), activeShardCount);
+    }
+
     private DiscoveryNode newNode(String nodeId) {
         final Set<DiscoveryNodeRole> roles = Collections.unmodifiableSet(
             new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE, DiscoveryNodeRole.DATA_ROLE))
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponseTests.java
index 802257357b7a8..91968e84c13dc 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsResponseTests.java
@@ -36,10 +36,10 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.xcontent.ToXContent;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsTests.java b/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsTests.java
index 171639083be58..0c4ad757efc1f 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/stats/IndicesStatsTests.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.action.admin.indices.stats;
 
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.index.IndexResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
-import org.opensearch.common.Strings;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.engine.SegmentsStats;
@@ -146,7 +147,7 @@ public void testRefreshListeners() throws Exception {
             }
             if (end - System.nanoTime() < 0) {
                 logger.info("timed out");
-                fail("didn't get a refresh listener in time: " + Strings.toString(common));
+                fail("didn't get a refresh listener in time: " + Strings.toString(MediaTypeRegistry.JSON, common));
             }
         }
 
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateRequestTests.java
index 01655d2ca3e7f..47a5600eef53a 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/delete/DeleteComposableIndexTemplateRequestTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.indices.template.delete;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateResponseTests.java
index e499e84ad9df7..ec175055f679b 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComponentTemplateResponseTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.metadata.ComponentTemplate;
 import org.opensearch.cluster.metadata.ComponentTemplateTests;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateRequestTests.java
index 39ab3be7c6dbd..a07296945f910 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateRequestTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.indices.template.get;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateResponseTests.java
index 6826d18938e61..9d170330536c2 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetComposableIndexTemplateResponseTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.ComposableIndexTemplateTests;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponseTests.java
index 7f62861d4f332..505b89b678227 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/get/GetIndexTemplatesResponseTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequestTests.java
index eaf676d58f45d..501d17141bd6f 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateIndexTemplateRequestTests.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
-import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.ComposableIndexTemplateTests;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Template;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateRequestTests.java
index 87ee57a7a3b9b..328e20a9ab508 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/post/SimulateTemplateRequestTests.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.admin.indices.template.put.PutComposableIndexTemplateAction;
-import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.ComposableIndexTemplateTests;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Template;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateRequestTests.java
index 98e833b051032..093228f5f1430 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutComposableIndexTemplateRequestTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.action.admin.indices.template.put;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.ComposableIndexTemplateTests;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Template;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
@@ -71,15 +71,7 @@ protected PutComposableIndexTemplateAction.Request mutateInstance(PutComposableI
 
     public void testPutGlobalTemplatesCannotHaveHiddenIndexSetting() {
         Template template = new Template(Settings.builder().put(IndexMetadata.SETTING_INDEX_HIDDEN, true).build(), null, null);
-        ComposableIndexTemplate globalTemplate = new ComposableIndexTemplate(
-            org.opensearch.common.collect.List.of("*"),
-            template,
-            null,
-            null,
-            null,
-            null,
-            null
-        );
+        ComposableIndexTemplate globalTemplate = new ComposableIndexTemplate(List.of("*"), template, null, null, null, null, null);
 
         PutComposableIndexTemplateAction.Request request = new PutComposableIndexTemplateAction.Request("test");
         request.indexTemplate(globalTemplate);
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java b/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
index f4cdb778a3169..d7876ea71045a 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
@@ -35,10 +35,11 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.AbstractXContentTestCase;
 
@@ -76,7 +77,7 @@ public void testMappingKeyedByType() throws IOException {
         PutIndexTemplateRequest request1 = new PutIndexTemplateRequest("foo");
         PutIndexTemplateRequest request2 = new PutIndexTemplateRequest("bar");
         {
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject()
                 .startObject("properties")
                 .startObject("field1")
@@ -92,7 +93,7 @@ public void testMappingKeyedByType() throws IOException {
                 .endObject()
                 .endObject();
             request1.mapping(builder);
-            builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject()
                 .startObject("properties")
                 .startObject("field1")
@@ -114,8 +115,8 @@ public void testMappingKeyedByType() throws IOException {
             request1 = new PutIndexTemplateRequest("foo");
             request2 = new PutIndexTemplateRequest("bar");
             String nakedMapping = "{\"properties\": {\"foo\": {\"type\": \"integer\"}}}";
-            request1.mapping(nakedMapping, XContentType.JSON);
-            request2.mapping(nakedMapping, XContentType.JSON);
+            request1.mapping(nakedMapping, MediaTypeRegistry.JSON);
+            request2.mapping(nakedMapping, MediaTypeRegistry.JSON);
             assertEquals(request1.mappings(), request2.mappings());
         }
         {
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/QueryExplanationTests.java b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/QueryExplanationTests.java
index ee2b3bdcfe065..f30b5f1211e23 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/QueryExplanationTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/QueryExplanationTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.admin.indices.validate.query;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryActionTests.java
index c1c0e9517607a..40790d05c89f5 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/TransportValidateQueryActionTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.admin.indices.validate.query;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.concurrent.atomic.AtomicBoolean;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponseTests.java b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponseTests.java
index 1da1cc28d50ed..4cea2c90cff33 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/validate/query/ValidateQueryResponseTests.java
@@ -33,9 +33,10 @@
 package org.opensearch.action.admin.indices.validate.query;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractBroadcastResponseTestCase;
 
 import java.io.IOException;
@@ -114,7 +115,7 @@ protected ValidateQueryResponse createTestInstance(
     @Override
     public void testToXContent() {
         ValidateQueryResponse response = createTestInstance(10, 10, 0, new ArrayList<>());
-        String output = Strings.toString(response);
+        String output = Strings.toString(MediaTypeRegistry.JSON, response);
         assertEquals("{\"_shards\":{\"total\":10,\"successful\":10,\"failed\":0},\"valid\":true}", output);
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/bulk/BackoffPolicyTests.java b/server/src/test/java/org/opensearch/action/bulk/BackoffPolicyTests.java
index 1b7d848b626fe..2f9ae9a154f46 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BackoffPolicyTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BackoffPolicyTests.java
@@ -75,4 +75,45 @@ public void testWrapBackoffPolicy() {
             assertEquals(expectedRetries, retries.get());
         }
     }
+
+    public void testEqualJitterExponentialBackOffPolicy() {
+        int baseDelay = 10;
+        int maxDelay = 10000;
+        BackoffPolicy policy = BackoffPolicy.exponentialEqualJitterBackoff(baseDelay, maxDelay);
+        Iterator<TimeValue> iterator = policy.iterator();
+
+        // Assert equal jitter
+        int retriesTillMaxDelay = 10;
+        for (int i = 0; i < retriesTillMaxDelay; i++) {
+            TimeValue delay = iterator.next();
+            assertTrue(delay.getMillis() >= baseDelay * (1L << i) / 2);
+            assertTrue(delay.getMillis() <= baseDelay * (1L << i));
+        }
+
+        // Now policy should return max delay for next retries.
+        int retriesAfterMaxDelay = randomInt(10);
+        for (int i = 0; i < retriesAfterMaxDelay; i++) {
+            TimeValue delay = iterator.next();
+            assertTrue(delay.getMillis() >= maxDelay / 2);
+            assertTrue(delay.getMillis() <= maxDelay);
+        }
+    }
+
+    public void testExponentialBackOffPolicy() {
+        long baseDelay = 10;
+        int maxDelay = 10000;
+        long currentDelay = baseDelay;
+        BackoffPolicy policy = BackoffPolicy.exponentialFullJitterBackoff(baseDelay);
+        Iterator<TimeValue> iterator = policy.iterator();
+
+        // Assert equal jitter
+        int numberOfRetries = randomInt(20);
+
+        for (int i = 0; i < numberOfRetries; i++) {
+            TimeValue delay = iterator.next();
+            assertTrue(delay.getMillis() >= 0);
+            assertTrue(delay.getMillis() <= currentDelay);
+            currentDelay = currentDelay * 2;
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkItemResponseTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkItemResponseTests.java
index 808872fee6f96..cdf884ae988b3 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkItemResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkItemResponseTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkItemResponse.Failure;
@@ -41,11 +41,11 @@
 import org.opensearch.action.index.IndexResponseTests;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.action.update.UpdateResponseTests;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkPrimaryExecutionContextTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkPrimaryExecutionContextTests.java
index 5159135a22618..de096aee45bf9 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkPrimaryExecutionContextTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkPrimaryExecutionContextTests.java
@@ -40,9 +40,9 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.action.update.UpdateRequest;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkProcessorTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkProcessorTests.java
index 3a13afac5d977..6ff3ba473b5e9 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkProcessorTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkProcessorTests.java
@@ -35,14 +35,14 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexRequest;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.Scheduler;
 import org.opensearch.threadpool.TestThreadPool;
@@ -208,7 +208,7 @@ public void testConcurrentExecutions() throws Exception {
                         if (randomBoolean()) {
                             bulkProcessor.add(indexRequest);
                         } else {
-                            bulkProcessor.add(bytesReference, null, null, XContentType.JSON);
+                            bulkProcessor.add(bytesReference, null, null, MediaTypeRegistry.JSON);
                         }
                     } catch (Exception e) {
                         throw ExceptionsHelper.convertToRuntime(e);
@@ -334,7 +334,7 @@ public void testConcurrentExecutionsWithFlush() throws Exception {
                         if (randomBoolean()) {
                             bulkProcessor.add(indexRequest);
                         } else {
-                            bulkProcessor.add(bytesReference, null, null, XContentType.JSON);
+                            bulkProcessor.add(bytesReference, null, null, MediaTypeRegistry.JSON);
                         }
                     } catch (Exception e) {
                         throw ExceptionsHelper.convertToRuntime(e);
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkRequestModifierTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkRequestModifierTests.java
index e7e1166eb57fa..1c75b3348b194 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkRequestModifierTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkRequestModifierTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
@@ -58,7 +58,7 @@ public void testBulkRequestModifier() {
         int numRequests = scaledRandomIntBetween(8, 64);
         BulkRequest bulkRequest = new BulkRequest();
         for (int i = 0; i < numRequests; i++) {
-            bulkRequest.add(new IndexRequest("_index").id(String.valueOf(i)).source("{}", XContentType.JSON));
+            bulkRequest.add(new IndexRequest("_index").id(String.valueOf(i)).source("{}", MediaTypeRegistry.JSON));
         }
         CaptureActionListener actionListener = new CaptureActionListener();
         TransportBulkAction.BulkRequestModifier bulkRequestModifier = new TransportBulkAction.BulkRequestModifier(bulkRequest);
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkRequestParserTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkRequestParserTests.java
index 239bb19c5f6ad..4f07c098b0869 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkRequestParserTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkRequestParserTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.action.index.IndexRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
@@ -47,9 +47,9 @@ public class BulkRequestParserTests extends OpenSearchTestCase {
 
     public void testIndexRequest() throws IOException {
         BytesArray request = new BytesArray("{ \"index\":{ \"_id\": \"bar\" } }\n{}\n");
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
         final AtomicBoolean parsed = new AtomicBoolean();
-        parser.parse(request, "foo", null, null, null, null, false, XContentType.JSON, (indexRequest, type) -> {
+        parser.parse(request, "foo", null, null, null, null, false, MediaTypeRegistry.JSON, indexRequest -> {
             assertFalse(parsed.get());
             assertEquals("foo", indexRequest.index());
             assertEquals("bar", indexRequest.id());
@@ -58,81 +58,39 @@ public void testIndexRequest() throws IOException {
         }, req -> fail(), req -> fail());
         assertTrue(parsed.get());
 
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            true,
-            false,
-            XContentType.JSON,
-            (indexRequest, type) -> { assertTrue(indexRequest.isRequireAlias()); },
-            req -> fail(),
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, true, false, MediaTypeRegistry.JSON, indexRequest -> {
+            assertTrue(indexRequest.isRequireAlias());
+        }, req -> fail(), req -> fail());
 
         request = new BytesArray("{ \"index\":{ \"_id\": \"bar\", \"require_alias\": true } }\n{}\n");
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            null,
-            false,
-            XContentType.JSON,
-            (indexRequest, type) -> { assertTrue(indexRequest.isRequireAlias()); },
-            req -> fail(),
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, null, false, MediaTypeRegistry.JSON, indexRequest -> {
+            assertTrue(indexRequest.isRequireAlias());
+        }, req -> fail(), req -> fail());
 
         request = new BytesArray("{ \"index\":{ \"_id\": \"bar\", \"require_alias\": false } }\n{}\n");
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            true,
-            false,
-            XContentType.JSON,
-            (indexRequest, type) -> { assertFalse(indexRequest.isRequireAlias()); },
-            req -> fail(),
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, true, false, MediaTypeRegistry.JSON, indexRequest -> {
+            assertFalse(indexRequest.isRequireAlias());
+        }, req -> fail(), req -> fail());
     }
 
     public void testDeleteRequest() throws IOException {
         BytesArray request = new BytesArray("{ \"delete\":{ \"_id\": \"bar\" } }\n");
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
         final AtomicBoolean parsed = new AtomicBoolean();
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            null,
-            false,
-            XContentType.JSON,
-            (req, type) -> fail(),
-            req -> fail(),
-            deleteRequest -> {
-                assertFalse(parsed.get());
-                assertEquals("foo", deleteRequest.index());
-                assertEquals("bar", deleteRequest.id());
-                parsed.set(true);
-            }
-        );
+        parser.parse(request, "foo", null, null, null, null, false, MediaTypeRegistry.JSON, req -> fail(), req -> fail(), deleteRequest -> {
+            assertFalse(parsed.get());
+            assertEquals("foo", deleteRequest.index());
+            assertEquals("bar", deleteRequest.id());
+            parsed.set(true);
+        });
         assertTrue(parsed.get());
     }
 
     public void testUpdateRequest() throws IOException {
         BytesArray request = new BytesArray("{ \"update\":{ \"_id\": \"bar\" } }\n{}\n");
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
         final AtomicBoolean parsed = new AtomicBoolean();
-        parser.parse(request, "foo", null, null, null, null, false, XContentType.JSON, (req, type) -> fail(), updateRequest -> {
+        parser.parse(request, "foo", null, null, null, null, false, MediaTypeRegistry.JSON, req -> fail(), updateRequest -> {
             assertFalse(parsed.get());
             assertEquals("foo", updateRequest.index());
             assertEquals("bar", updateRequest.id());
@@ -141,54 +99,24 @@ public void testUpdateRequest() throws IOException {
         }, req -> fail());
         assertTrue(parsed.get());
 
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            true,
-            false,
-            XContentType.JSON,
-            (req, type) -> fail(),
-            updateRequest -> { assertTrue(updateRequest.isRequireAlias()); },
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, true, false, MediaTypeRegistry.JSON, req -> fail(), updateRequest -> {
+            assertTrue(updateRequest.isRequireAlias());
+        }, req -> fail());
 
         request = new BytesArray("{ \"update\":{ \"_id\": \"bar\", \"require_alias\": true } }\n{}\n");
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            null,
-            false,
-            XContentType.JSON,
-            (req, type) -> fail(),
-            updateRequest -> { assertTrue(updateRequest.isRequireAlias()); },
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, null, false, MediaTypeRegistry.JSON, req -> fail(), updateRequest -> {
+            assertTrue(updateRequest.isRequireAlias());
+        }, req -> fail());
 
         request = new BytesArray("{ \"update\":{ \"_id\": \"bar\", \"require_alias\": false } }\n{}\n");
-        parser.parse(
-            request,
-            "foo",
-            null,
-            null,
-            null,
-            true,
-            false,
-            XContentType.JSON,
-            (req, type) -> fail(),
-            updateRequest -> { assertFalse(updateRequest.isRequireAlias()); },
-            req -> fail()
-        );
+        parser.parse(request, "foo", null, null, null, true, false, MediaTypeRegistry.JSON, req -> fail(), updateRequest -> {
+            assertFalse(updateRequest.isRequireAlias());
+        }, req -> fail());
     }
 
     public void testBarfOnLackOfTrailingNewline() {
         BytesArray request = new BytesArray("{ \"index\":{ \"_id\": \"bar\" } }\n{}");
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
             () -> parser.parse(
@@ -199,8 +127,8 @@ public void testBarfOnLackOfTrailingNewline() {
                 null,
                 null,
                 false,
-                XContentType.JSON,
-                (indexRequest, type) -> fail(),
+                MediaTypeRegistry.JSON,
+                indexRequest -> fail(),
                 req -> fail(),
                 req -> fail()
             )
@@ -210,7 +138,7 @@ public void testBarfOnLackOfTrailingNewline() {
 
     public void testFailOnExplicitIndex() {
         BytesArray request = new BytesArray("{ \"index\":{ \"_index\": \"foo\", \"_id\": \"bar\" } }\n{}\n");
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
 
         IllegalArgumentException ex = expectThrows(
             IllegalArgumentException.class,
@@ -222,8 +150,8 @@ public void testFailOnExplicitIndex() {
                 null,
                 null,
                 false,
-                XContentType.JSON,
-                (req, type) -> fail(),
+                MediaTypeRegistry.JSON,
+                req -> fail(),
                 req -> fail(),
                 req -> fail()
             )
@@ -231,25 +159,12 @@ public void testFailOnExplicitIndex() {
         assertEquals("explicit index in bulk is not allowed", ex.getMessage());
     }
 
-    public void testTypesStillParsedForBulkMonitoring() throws IOException {
-        BytesArray request = new BytesArray("{ \"index\":{ \"_type\": \"quux\", \"_id\": \"bar\" } }\n{}\n");
-        BulkRequestParser parser = new BulkRequestParser(false);
-        final AtomicBoolean parsed = new AtomicBoolean();
-        parser.parse(request, "foo", null, null, null, null, false, XContentType.JSON, (indexRequest, type) -> {
-            assertFalse(parsed.get());
-            assertEquals("foo", indexRequest.index());
-            assertEquals("bar", indexRequest.id());
-            parsed.set(true);
-        }, req -> fail(), req -> fail());
-        assertTrue(parsed.get());
-    }
-
     public void testParseDeduplicatesParameterStrings() throws IOException {
         BytesArray request = new BytesArray(
             "{ \"index\":{ \"_index\": \"bar\", \"pipeline\": \"foo\", \"routing\": \"blub\"} }\n{}\n"
                 + "{ \"index\":{ \"_index\": \"bar\", \"pipeline\": \"foo\", \"routing\": \"blub\" } }\n{}\n"
         );
-        BulkRequestParser parser = new BulkRequestParser(randomBoolean());
+        BulkRequestParser parser = new BulkRequestParser();
         final List<IndexRequest> indexRequests = new ArrayList<>();
         parser.parse(
             request,
@@ -259,8 +174,8 @@ public void testParseDeduplicatesParameterStrings() throws IOException {
             null,
             null,
             true,
-            XContentType.JSON,
-            (indexRequest, type) -> indexRequests.add(indexRequest),
+            MediaTypeRegistry.JSON,
+            indexRequest -> indexRequests.add(indexRequest),
             req -> fail(),
             req -> fail()
         );
@@ -271,4 +186,30 @@ public void testParseDeduplicatesParameterStrings() throws IOException {
         assertSame(first.getPipeline(), second.getPipeline());
         assertSame(first.routing(), second.routing());
     }
+
+    public void testFailOnUnsupportedAction() {
+        BytesArray request = new BytesArray("{ \"baz\":{ \"_id\": \"bar\" } }\n{}\n");
+        BulkRequestParser parser = new BulkRequestParser();
+
+        IllegalArgumentException ex = expectThrows(
+            IllegalArgumentException.class,
+            () -> parser.parse(
+                request,
+                "foo",
+                null,
+                null,
+                null,
+                true,
+                false,
+                MediaTypeRegistry.JSON,
+                req -> fail(),
+                req -> fail(),
+                req -> fail()
+            )
+        );
+        assertEquals(
+            "Malformed action/metadata line [1], expected one of [create, delete, index, update] but found [baz]",
+            ex.getMessage()
+        );
+    }
 }
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkRequestTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkRequestTests.java
index 9fd57a78d2097..b3a5cff0041a7 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkRequestTests.java
@@ -39,20 +39,21 @@
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.client.Requests;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.Script;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -70,7 +71,7 @@ public class BulkRequestTests extends OpenSearchTestCase {
     public void testSimpleBulk1() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
         assertThat(((IndexRequest) bulkRequest.requests().get(0)).source(), equalTo(new BytesArray("{ \"field1\" : \"value1\" }")));
         assertThat(bulkRequest.requests().get(1), instanceOf(DeleteRequest.class));
@@ -80,13 +81,13 @@ public void testSimpleBulk1() throws Exception {
     public void testSimpleBulkWithCarriageReturn() throws Exception {
         String bulkAction = "{ \"index\":{\"_index\":\"test\",\"_id\":\"1\"} }\r\n{ \"field1\" : \"value1\" }\r\n";
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(1));
         assertThat(((IndexRequest) bulkRequest.requests().get(0)).source(), equalTo(new BytesArray("{ \"field1\" : \"value1\" }")));
         Map<String, Object> sourceMap = XContentHelper.convertToMap(
             ((IndexRequest) bulkRequest.requests().get(0)).source(),
             false,
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).v2();
         assertEquals("value1", sourceMap.get("field1"));
     }
@@ -94,21 +95,21 @@ public void testSimpleBulkWithCarriageReturn() throws Exception {
     public void testSimpleBulk2() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk2.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
     }
 
     public void testSimpleBulk3() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk3.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
     }
 
     public void testSimpleBulk4() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk4.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(4));
         assertThat(bulkRequest.requests().get(0).id(), equalTo("1"));
         assertThat(((UpdateRequest) bulkRequest.requests().get(0)).retryOnConflict(), equalTo(2));
@@ -130,12 +131,12 @@ public void testBulkAllowExplicitIndex() throws Exception {
         String bulkAction1 = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk.json");
         Exception ex = expectThrows(
             Exception.class,
-            () -> new BulkRequest().add(new BytesArray(bulkAction1.getBytes(StandardCharsets.UTF_8)), null, false, XContentType.JSON)
+            () -> new BulkRequest().add(new BytesArray(bulkAction1.getBytes(StandardCharsets.UTF_8)), null, false, MediaTypeRegistry.JSON)
         );
         assertEquals("explicit index in bulk is not allowed", ex.getMessage());
 
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk5.json");
-        new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), "test", false, XContentType.JSON);
+        new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), "test", false, MediaTypeRegistry.JSON);
     }
 
     public void testBulkAddIterable() {
@@ -156,7 +157,7 @@ public void testSimpleBulk6() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         ParsingException exc = expectThrows(
             ParsingException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertThat(exc.getMessage(), containsString("Unknown key for a VALUE_STRING in [hello]"));
     }
@@ -166,7 +167,7 @@ public void testSimpleBulk7() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertThat(
             exc.getMessage(),
@@ -179,7 +180,7 @@ public void testSimpleBulk8() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertThat(exc.getMessage(), containsString("Action/metadata line [3] contains an unknown parameter [_foo]"));
     }
@@ -189,7 +190,7 @@ public void testSimpleBulk9() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertThat(
             exc.getMessage(),
@@ -200,7 +201,7 @@ public void testSimpleBulk9() throws Exception {
     public void testSimpleBulk10() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk10.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(9));
     }
 
@@ -209,7 +210,7 @@ public void testBulkActionShouldNotContainArray() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertEquals(
             exc.getMessage(),
@@ -239,7 +240,7 @@ public void testBulkEmptyObject() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertThat(
             exc.getMessage(),
@@ -255,8 +256,8 @@ public void testBulkRequestWithRefresh() throws Exception {
         // We force here a "type is missing" validation error
         bulkRequest.add(new DeleteRequest("index", "id"));
         bulkRequest.add(new DeleteRequest("index", "id").setRefreshPolicy(RefreshPolicy.IMMEDIATE));
-        bulkRequest.add(new UpdateRequest("index", "id").doc("{}", XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
-        bulkRequest.add(new IndexRequest("index").id("id").source("{}", XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
+        bulkRequest.add(new UpdateRequest("index", "id").doc("{}", MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
+        bulkRequest.add(new IndexRequest("index").id("id").source("{}", MediaTypeRegistry.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
         ActionRequestValidationException validate = bulkRequest.validate();
         assertThat(validate, notNullValue());
         assertThat(validate.validationErrors(), not(empty()));
@@ -272,6 +273,51 @@ public void testBulkRequestWithRefresh() throws Exception {
         );
     }
 
+    public void testBulkRequestInvalidDocIDDuringCreate() {
+        String validDocID = String.join("", Collections.nCopies(512, "a"));
+        String invalidDocID = String.join("", Collections.nCopies(513, "a"));
+
+        // doc id length under limit
+        IndexRequest indexRequest = new IndexRequest("index").id(validDocID).source(Requests.INDEX_CONTENT_TYPE, "field", "value");
+        BulkRequest bulkRequest = new BulkRequest();
+        bulkRequest.add(indexRequest);
+        assertNull(bulkRequest.validate());
+
+        // doc id length over limit
+        indexRequest.id(invalidDocID);
+        ActionRequestValidationException validate = bulkRequest.validate();
+        assertThat(validate, notNullValue());
+        assertEquals(
+            1,
+            validate.validationErrors()
+                .stream()
+                .filter(msg -> msg.contains("is too long, must be no longer than 512 bytes but was: "))
+                .count()
+        );
+    }
+
+    public void testBulkRequestInvalidDocIDDuringUpdate() {
+        String validDocID = String.join("", Collections.nCopies(512, "a"));
+        String invalidDocID = String.join("", Collections.nCopies(513, "a"));
+        // doc id length under limit
+        UpdateRequest updateRequest = new UpdateRequest("index", validDocID).doc("reason", "no source");
+        BulkRequest bulkRequest = new BulkRequest();
+        bulkRequest.add(updateRequest);
+        assertNull(bulkRequest.validate());
+
+        // doc id length over limit
+        updateRequest.id(invalidDocID);
+        ActionRequestValidationException validate = bulkRequest.validate();
+        assertThat(validate, notNullValue());
+        assertEquals(
+            1,
+            validate.validationErrors()
+                .stream()
+                .filter(msg -> msg.contains("is too long, must be no longer than 512 bytes but was: "))
+                .count()
+        );
+    }
+
     // issue 15120
     public void testBulkNoSource() throws Exception {
         BulkRequest bulkRequest = new BulkRequest();
@@ -294,7 +340,7 @@ public void testSmileIsSupported() throws IOException {
         XContentType xContentType = XContentType.SMILE;
         BytesReference data;
         try (BytesStreamOutput out = new BytesStreamOutput()) {
-            try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType, out)) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType, out)) {
                 builder.startObject();
                 builder.startObject("index");
                 builder.field("_index", "index");
@@ -303,7 +349,7 @@ public void testSmileIsSupported() throws IOException {
                 builder.endObject();
             }
             out.write(xContentType.xContent().streamSeparator());
-            try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType, out)) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType, out)) {
                 builder.startObject();
                 builder.field("field", "value");
                 builder.endObject();
@@ -329,7 +375,7 @@ public void testToValidateUpsertRequestAndCASInBulkRequest() throws IOException
         XContentType xContentType = XContentType.SMILE;
         BytesReference data;
         try (BytesStreamOutput out = new BytesStreamOutput()) {
-            try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType, out)) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType, out)) {
                 builder.startObject();
                 builder.startObject("update");
                 builder.field("_index", "index");
@@ -340,7 +386,7 @@ public void testToValidateUpsertRequestAndCASInBulkRequest() throws IOException
                 builder.endObject();
             }
             out.write(xContentType.xContent().streamSeparator());
-            try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType, out)) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType, out)) {
                 builder.startObject();
                 builder.startObject("doc").endObject();
                 Map<String, Object> values = new HashMap<>();
@@ -362,7 +408,7 @@ public void testBulkTerminatedByNewline() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/opensearch/action/bulk/simple-bulk11.json");
         IllegalArgumentException expectThrows = expectThrows(
             IllegalArgumentException.class,
-            () -> new BulkRequest().add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON)
+            () -> new BulkRequest().add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON)
         );
         assertEquals("The bulk request must be terminated by a newline [\\n]", expectThrows.getMessage());
 
@@ -373,7 +419,7 @@ public void testBulkTerminatedByNewline() throws Exception {
             0,
             bulkActionWithNewLine.length(),
             null,
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         assertEquals(3, bulkRequestWithNewLine.numberOfActions());
     }
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkResponseTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkResponseTests.java
index e768d66ee04ce..0627518bb60ce 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkResponseTests.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.delete.DeleteResponseTests;
 import org.opensearch.action.index.IndexResponseTests;
 import org.opensearch.action.update.UpdateResponseTests;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -51,7 +51,7 @@
 import static org.opensearch.OpenSearchExceptionTests.randomExceptions;
 import static org.opensearch.action.bulk.BulkItemResponseTests.assertBulkItemResponse;
 import static org.opensearch.action.bulk.BulkResponse.NO_INGEST_TOOK;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class BulkResponseTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/action/bulk/BulkShardRequestTests.java b/server/src/test/java/org/opensearch/action/bulk/BulkShardRequestTests.java
index 5aa4553133190..05c946e73f94d 100644
--- a/server/src/test/java/org/opensearch/action/bulk/BulkShardRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/BulkShardRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
diff --git a/server/src/test/java/org/opensearch/action/bulk/RetryTests.java b/server/src/test/java/org/opensearch/action/bulk/RetryTests.java
index d3280ede6ce15..aa33372239fed 100644
--- a/server/src/test/java/org/opensearch/action/bulk/RetryTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/RetryTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.action.bulk;
 
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest.OpType;
 import org.opensearch.action.delete.DeleteResponse;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.update.UpdateRequest;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 import org.junit.After;
diff --git a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIndicesThatCannotBeCreatedTests.java b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIndicesThatCannotBeCreatedTests.java
index 32e9dd44008cd..0f67eff26cbde 100644
--- a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIndicesThatCannotBeCreatedTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIndicesThatCannotBeCreatedTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.index.IndexRequest;
@@ -49,6 +48,7 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.VersionType;
@@ -96,11 +96,9 @@ public void testAllFail() {
         bulkRequest.add(new IndexRequest("can't"));
         bulkRequest.add(new DeleteRequest("do").version(0).versionType(VersionType.EXTERNAL));
         bulkRequest.add(new UpdateRequest("nothin", randomAlphaOfLength(5)));
-        indicesThatCannotBeCreatedTestCase(
-            new HashSet<>(Arrays.asList("no", "can't", "do", "nothin")),
-            bulkRequest,
-            index -> { throw new IndexNotFoundException("Can't make it because I say so"); }
-        );
+        indicesThatCannotBeCreatedTestCase(new HashSet<>(Arrays.asList("no", "can't", "do", "nothin")), bulkRequest, index -> {
+            throw new IndexNotFoundException("Can't make it because I say so");
+        });
     }
 
     public void testSomeFail() {
@@ -156,6 +154,7 @@ private void indicesThatCannotBeCreatedTestCase(
                 Settings.EMPTY,
                 new ClusterService(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), null)
             ),
+            null,
             new SystemIndices(emptyMap())
         ) {
             @Override
diff --git a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIngestTests.java b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIngestTests.java
index 4b98870422ce8..515f6eae28a34 100644
--- a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIngestTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionIngestTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.bulk;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.index.IndexAction;
@@ -47,17 +46,16 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.metadata.AliasMetadata;
+import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
-import org.opensearch.cluster.metadata.ComposableIndexTemplate;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.Template;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
@@ -65,6 +63,7 @@
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.IndexingPressureService;
@@ -78,24 +77,27 @@
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiConsumer;
 
+import org.mockito.ArgumentCaptor;
+
 import static java.util.Collections.emptyMap;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.sameInstance;
+import static org.mockito.Answers.RETURNS_MOCKS;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyString;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.reset;
@@ -169,6 +171,7 @@ class TestTransportBulkAction extends TransportBulkAction {
                     SETTINGS,
                     new ClusterService(SETTINGS, new ClusterSettings(SETTINGS, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), null)
                 ),
+                null,
                 new SystemIndices(emptyMap())
             );
         }
@@ -224,7 +227,7 @@ public void setupAction() {
         remoteResponseHandler = ArgumentCaptor.forClass(TransportResponseHandler.class);
 
         // setup services that will be called by action
-        transportService = mock(TransportService.class);
+        transportService = mock(TransportService.class, RETURNS_MOCKS);
         clusterService = mock(ClusterService.class);
         localIngest = true;
         // setup nodes for local and remote
@@ -234,42 +237,37 @@ public void setupAction() {
         remoteNode1 = mock(DiscoveryNode.class);
         remoteNode2 = mock(DiscoveryNode.class);
         nodes = mock(DiscoveryNodes.class);
-        ImmutableOpenMap<String, DiscoveryNode> ingestNodes = ImmutableOpenMap.<String, DiscoveryNode>builder(2)
-            .fPut("node1", remoteNode1)
-            .fPut("node2", remoteNode2)
-            .build();
+        final Map<String, DiscoveryNode> ingestNodes = Map.of("node1", remoteNode1, "node2", remoteNode2);
         when(nodes.getIngestNodes()).thenReturn(ingestNodes);
         when(nodes.getMinNodeVersion()).thenReturn(VersionUtils.randomCompatibleVersion(random(), Version.CURRENT));
         ClusterState state = mock(ClusterState.class);
         when(state.getNodes()).thenReturn(nodes);
         Metadata metadata = Metadata.builder()
             .indices(
-                ImmutableOpenMap.<String, IndexMetadata>builder()
-                    .putAll(
-                        MapBuilder.<String, IndexMetadata>newMapBuilder()
-                            .put(
-                                WITH_DEFAULT_PIPELINE,
-                                IndexMetadata.builder(WITH_DEFAULT_PIPELINE)
-                                    .settings(
-                                        settings(Version.CURRENT).put(IndexSettings.DEFAULT_PIPELINE.getKey(), "default_pipeline").build()
-                                    )
-                                    .putAlias(AliasMetadata.builder(WITH_DEFAULT_PIPELINE_ALIAS).build())
-                                    .numberOfShards(1)
-                                    .numberOfReplicas(1)
-                                    .build()
-                            )
-                            .put(
-                                ".system",
-                                IndexMetadata.builder(".system")
-                                    .settings(settings(Version.CURRENT))
-                                    .system(true)
-                                    .numberOfShards(1)
-                                    .numberOfReplicas(0)
-                                    .build()
-                            )
-                            .map()
-                    )
-                    .build()
+                new HashMap<>(
+                    MapBuilder.<String, IndexMetadata>newMapBuilder()
+                        .put(
+                            WITH_DEFAULT_PIPELINE,
+                            IndexMetadata.builder(WITH_DEFAULT_PIPELINE)
+                                .settings(
+                                    settings(Version.CURRENT).put(IndexSettings.DEFAULT_PIPELINE.getKey(), "default_pipeline").build()
+                                )
+                                .putAlias(AliasMetadata.builder(WITH_DEFAULT_PIPELINE_ALIAS).build())
+                                .numberOfShards(1)
+                                .numberOfReplicas(1)
+                                .build()
+                        )
+                        .put(
+                            ".system",
+                            IndexMetadata.builder(".system")
+                                .settings(settings(Version.CURRENT))
+                                .system(true)
+                                .numberOfShards(1)
+                                .numberOfReplicas(0)
+                                .build()
+                        )
+                        .map()
+                )
             )
             .build();
         when(state.getMetadata()).thenReturn(metadata);
@@ -301,11 +299,9 @@ public void testIngestSkipped() throws Exception {
     public void testSingleItemBulkActionIngestSkipped() throws Exception {
         IndexRequest indexRequest = new IndexRequest("index").id("id");
         indexRequest.source(emptyMap());
-        singleItemBulkWriteAction.execute(
-            null,
-            indexRequest,
-            ActionListener.wrap(response -> {}, exception -> { throw new AssertionError(exception); })
-        );
+        singleItemBulkWriteAction.execute(null, indexRequest, ActionListener.wrap(response -> {}, exception -> {
+            throw new AssertionError(exception);
+        }));
         assertTrue(action.isExecuted);
         verifyNoInteractions(ingestService);
     }
@@ -660,7 +656,7 @@ public void testFindDefaultPipelineFromTemplateMatch() {
         Exception exception = new Exception("fake exception");
         ClusterState state = clusterService.state();
 
-        ImmutableOpenMap.Builder<String, IndexTemplateMetadata> templateMetadataBuilder = ImmutableOpenMap.builder();
+        final Map<String, IndexTemplateMetadata> templateMetadataBuilder = new HashMap<>();
         templateMetadataBuilder.put(
             "template1",
             IndexTemplateMetadata.builder("template1")
@@ -693,9 +689,9 @@ public void testFindDefaultPipelineFromTemplateMatch() {
         Metadata metadata = mock(Metadata.class);
         when(state.metadata()).thenReturn(metadata);
         when(state.getMetadata()).thenReturn(metadata);
-        when(metadata.templates()).thenReturn(templateMetadataBuilder.build());
-        when(metadata.getTemplates()).thenReturn(templateMetadataBuilder.build());
-        when(metadata.indices()).thenReturn(ImmutableOpenMap.of());
+        when(metadata.templates()).thenReturn(templateMetadataBuilder);
+        when(metadata.getTemplates()).thenReturn(templateMetadataBuilder);
+        when(metadata.indices()).thenReturn(Map.of());
 
         IndexRequest indexRequest = new IndexRequest("missing_index").id("id");
         indexRequest.source(emptyMap());
diff --git a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTests.java b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTests.java
index 5eb395cb05971..10cad6fb147a2 100644
--- a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTests.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.bulk.TransportBulkActionTookTests.Resolver;
@@ -56,12 +55,15 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.VersionType;
+import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndexDescriptor;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.transport.CapturingTransport;
@@ -74,6 +76,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.SortedMap;
 import java.util.TreeMap;
 import java.util.concurrent.TimeUnit;
@@ -86,6 +89,7 @@
 import static org.opensearch.test.ClusterServiceUtils.createClusterService;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
+import static org.mockito.Mockito.mock;
 
 public class TransportBulkActionTests extends OpenSearchTestCase {
 
@@ -113,6 +117,7 @@ class TestTransportBulkAction extends TransportBulkAction {
                 new Resolver(),
                 new AutoCreateIndex(Settings.EMPTY, clusterService.getClusterSettings(), new Resolver(), new SystemIndices(emptyMap())),
                 new IndexingPressureService(Settings.EMPTY, clusterService),
+                mock(IndicesService.class),
                 new SystemIndices(emptyMap())
             );
         }
@@ -152,7 +157,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -343,19 +349,17 @@ public void testIncludesSystem() {
             ".bar",
             new Index(IndexMetadata.builder(".bar").settings(settings).system(true).numberOfShards(1).numberOfReplicas(0).build())
         );
-        SystemIndices systemIndices = new SystemIndices(
-            org.opensearch.common.collect.Map.of("plugin", org.opensearch.common.collect.List.of(new SystemIndexDescriptor(".test", "")))
-        );
-        List<String> onlySystem = org.opensearch.common.collect.List.of(".foo", ".bar");
+        SystemIndices systemIndices = new SystemIndices(Map.of("plugin", List.of(new SystemIndexDescriptor(".test", ""))));
+        List<String> onlySystem = List.of(".foo", ".bar");
         assertTrue(bulkAction.includesSystem(buildBulkRequest(onlySystem), indicesLookup, systemIndices));
 
-        onlySystem = org.opensearch.common.collect.List.of(".foo", ".bar", ".test");
+        onlySystem = List.of(".foo", ".bar", ".test");
         assertTrue(bulkAction.includesSystem(buildBulkRequest(onlySystem), indicesLookup, systemIndices));
 
-        List<String> nonSystem = org.opensearch.common.collect.List.of("foo", "bar");
+        List<String> nonSystem = List.of("foo", "bar");
         assertFalse(bulkAction.includesSystem(buildBulkRequest(nonSystem), indicesLookup, systemIndices));
 
-        List<String> mixed = org.opensearch.common.collect.List.of(".foo", ".test", "other");
+        List<String> mixed = List.of(".foo", ".test", "other");
         assertTrue(bulkAction.includesSystem(buildBulkRequest(mixed), indicesLookup, systemIndices));
     }
 
diff --git a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTookTests.java b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTookTests.java
index 713b506f14299..852e3837e1e7a 100644
--- a/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTookTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/TransportBulkActionTookTests.java
@@ -33,11 +33,9 @@
 package org.opensearch.action.bulk;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.action.ActionType;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.support.ActionFilters;
@@ -48,15 +46,18 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.transport.CapturingTransport;
@@ -125,7 +126,8 @@ private TransportBulkAction createAction(boolean controlled, AtomicLong expected
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -217,7 +219,7 @@ private void runTestTook(boolean controlled) throws Exception {
             bulkAction = Strings.replace(bulkAction, "\r\n", "\n");
         }
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, XContentType.JSON);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, MediaTypeRegistry.JSON);
         AtomicLong expected = new AtomicLong();
         TransportBulkAction action = createAction(controlled, expected);
         action.doExecute(null, bulkRequest, new ActionListener<BulkResponse>() {
@@ -278,6 +280,7 @@ static class TestTransportBulkAction extends TransportBulkAction {
                 indexNameExpressionResolver,
                 autoCreateIndex,
                 new IndexingPressureService(Settings.EMPTY, clusterService),
+                null,
                 new SystemIndices(emptyMap()),
                 relativeTimeProvider
             );
diff --git a/server/src/test/java/org/opensearch/action/bulk/TransportShardBulkActionTests.java b/server/src/test/java/org/opensearch/action/bulk/TransportShardBulkActionTests.java
index b1fa20307a12b..fe0fdd07025d9 100644
--- a/server/src/test/java/org/opensearch/action/bulk/TransportShardBulkActionTests.java
+++ b/server/src/test/java/org/opensearch/action/bulk/TransportShardBulkActionTests.java
@@ -35,7 +35,6 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.OpenSearchStatusException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.LatchedActionListener;
@@ -43,18 +42,37 @@
 import org.opensearch.action.delete.DeleteResponse;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
+import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.WriteRequest.RefreshPolicy;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.action.support.replication.ReplicationTask;
+import org.opensearch.action.support.replication.TransportReplicationAction.ReplicaResponse;
 import org.opensearch.action.support.replication.TransportWriteAction.WritePrimaryResult;
 import org.opensearch.action.update.UpdateHelper;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.action.update.UpdateResponse;
 import org.opensearch.client.Requests;
+import org.opensearch.cluster.action.index.MappingUpdatedAction;
+import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.AllocationId;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.IndexingPressureService;
+import org.opensearch.index.SegmentReplicationPressureService;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.VersionConflictEngineException;
@@ -62,14 +80,20 @@
 import org.opensearch.index.mapper.Mapping;
 import org.opensearch.index.mapper.MetadataFieldMapper;
 import org.opensearch.index.mapper.RootObjectMapper;
+import org.opensearch.index.remote.RemoteStorePressureService;
+import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.SystemIndices;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
+import org.opensearch.transport.TestTransportChannel;
+import org.opensearch.transport.TransportChannel;
+import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -85,6 +109,7 @@
 import static org.hamcrest.Matchers.arrayWithSize;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyBoolean;
 import static org.mockito.Mockito.anyLong;
@@ -1030,6 +1055,169 @@ public void testForceExecutionOnRejectionAfterMappingUpdate() throws Exception {
         }
     }
 
+    public void testHandlePrimaryTermValidationRequestWithDifferentAllocationId() {
+
+        final String aId = "test-allocation-id";
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        final ReplicationTask task = createReplicationTask();
+        PlainActionFuture<TransportResponse> listener = new PlainActionFuture<>();
+        TransportShardBulkAction action = new TransportShardBulkAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            mockClusterService(),
+            mockIndicesService(aId, 1L),
+            threadPool,
+            mock(ShardStateAction.class),
+            mock(MappingUpdatedAction.class),
+            mock(UpdateHelper.class),
+            mock(ActionFilters.class),
+            mock(IndexingPressureService.class),
+            mock(SegmentReplicationPressureService.class),
+            mock(RemoteStorePressureService.class),
+            mock(SystemIndices.class)
+        );
+        action.handlePrimaryTermValidationRequest(
+            new TransportShardBulkAction.PrimaryTermValidationRequest(aId + "-1", 1, shardId),
+            createTransportChannel(listener),
+            task
+        );
+        assertThrows(ShardNotFoundException.class, listener::actionGet);
+        assertNotNull(task.getPhase());
+        assertEquals("failed", task.getPhase());
+    }
+
+    public void testHandlePrimaryTermValidationRequestWithOlderPrimaryTerm() {
+
+        final String aId = "test-allocation-id";
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        final ReplicationTask task = createReplicationTask();
+        PlainActionFuture<TransportResponse> listener = new PlainActionFuture<>();
+        TransportShardBulkAction action = new TransportShardBulkAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            mockClusterService(),
+            mockIndicesService(aId, 2L),
+            threadPool,
+            mock(ShardStateAction.class),
+            mock(MappingUpdatedAction.class),
+            mock(UpdateHelper.class),
+            mock(ActionFilters.class),
+            mock(IndexingPressureService.class),
+            mock(SegmentReplicationPressureService.class),
+            mock(RemoteStorePressureService.class),
+            mock(SystemIndices.class)
+        );
+        action.handlePrimaryTermValidationRequest(
+            new TransportShardBulkAction.PrimaryTermValidationRequest(aId, 1, shardId),
+            createTransportChannel(listener),
+            task
+        );
+        assertThrows(IllegalStateException.class, listener::actionGet);
+        assertNotNull(task.getPhase());
+        assertEquals("failed", task.getPhase());
+    }
+
+    public void testHandlePrimaryTermValidationRequestSuccess() {
+
+        final String aId = "test-allocation-id";
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        final ReplicationTask task = createReplicationTask();
+        PlainActionFuture<TransportResponse> listener = new PlainActionFuture<>();
+        TransportShardBulkAction action = new TransportShardBulkAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            mockClusterService(),
+            mockIndicesService(aId, 1L),
+            threadPool,
+            mock(ShardStateAction.class),
+            mock(MappingUpdatedAction.class),
+            mock(UpdateHelper.class),
+            mock(ActionFilters.class),
+            mock(IndexingPressureService.class),
+            mock(SegmentReplicationPressureService.class),
+            mock(RemoteStorePressureService.class),
+            mock(SystemIndices.class)
+        );
+        action.handlePrimaryTermValidationRequest(
+            new TransportShardBulkAction.PrimaryTermValidationRequest(aId, 1, shardId),
+            createTransportChannel(listener),
+            task
+        );
+        assertTrue(listener.actionGet() instanceof ReplicaResponse);
+        assertEquals(SequenceNumbers.NO_OPS_PERFORMED, ((ReplicaResponse) listener.actionGet()).localCheckpoint());
+        assertEquals(SequenceNumbers.NO_OPS_PERFORMED, ((ReplicaResponse) listener.actionGet()).globalCheckpoint());
+        assertNotNull(task.getPhase());
+        assertEquals("finished", task.getPhase());
+    }
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        TransportShardBulkAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.PRIMARY_TERM_VALIDATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        TransportShardBulkAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportShardBulkAction createAction() {
+        return new TransportShardBulkAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            mockClusterService(),
+            mock(IndicesService.class),
+            threadPool,
+            mock(ShardStateAction.class),
+            mock(MappingUpdatedAction.class),
+            mock(UpdateHelper.class),
+            mock(ActionFilters.class),
+            mock(IndexingPressureService.class),
+            mock(SegmentReplicationPressureService.class),
+            mock(RemoteStorePressureService.class),
+            mock(SystemIndices.class)
+        );
+    }
+
+    private ClusterService mockClusterService() {
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        return clusterService;
+    }
+
+    private IndicesService mockIndicesService(String aId, long primaryTerm) {
+        // Mock few of the required classes
+        IndicesService indicesService = mock(IndicesService.class);
+        IndexService indexService = mock(IndexService.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(indicesService.indexServiceSafe(any(Index.class))).thenReturn(indexService);
+        when(indexService.getShard(anyInt())).thenReturn(indexShard);
+        when(indexShard.getOperationPrimaryTerm()).thenReturn(primaryTerm);
+
+        // Mock routing entry, allocation id
+        AllocationId allocationId = mock(AllocationId.class);
+        ShardRouting shardRouting = mock(ShardRouting.class);
+        when(indexShard.routingEntry()).thenReturn(shardRouting);
+        when(shardRouting.allocationId()).thenReturn(allocationId);
+        when(allocationId.getId()).thenReturn(aId);
+        return indicesService;
+    }
+
+    private ReplicationTask createReplicationTask() {
+        return new ReplicationTask(0, null, null, null, null, null);
+    }
+
+    /**
+     * Transport channel that is needed for replica operation testing.
+     */
+    private TransportChannel createTransportChannel(final PlainActionFuture<TransportResponse> listener) {
+        return new TestTransportChannel(listener);
+    }
+
     private void randomlySetIgnoredPrimaryResponse(BulkItemRequest primaryRequest) {
         if (randomBoolean()) {
             // add a response to the request and thereby check that it is ignored for the primary.
diff --git a/server/src/test/java/org/opensearch/action/delete/DeleteResponseTests.java b/server/src/test/java/org/opensearch/action/delete/DeleteResponseTests.java
index e6c80b8ebdb61..a13fbf01e270e 100644
--- a/server/src/test/java/org/opensearch/action/delete/DeleteResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/delete/DeleteResponseTests.java
@@ -33,14 +33,15 @@
 package org.opensearch.action.delete;
 
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -56,7 +57,7 @@ public class DeleteResponseTests extends OpenSearchTestCase {
     public void testToXContent() {
         {
             DeleteResponse response = new DeleteResponse(new ShardId("index", "index_uuid", 0), "id", 3, 17, 5, true);
-            String output = Strings.toString(response);
+            String output = Strings.toString(MediaTypeRegistry.JSON, response);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":5,\"result\":\"deleted\","
                     + "\"_shards\":null,\"_seq_no\":3,\"_primary_term\":17}",
@@ -67,7 +68,7 @@ public void testToXContent() {
             DeleteResponse response = new DeleteResponse(new ShardId("index", "index_uuid", 0), "id", -1, 0, 7, true);
             response.setForcedRefresh(true);
             response.setShardInfo(new ReplicationResponse.ShardInfo(10, 5));
-            String output = Strings.toString(response);
+            String output = Strings.toString(MediaTypeRegistry.JSON, response);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":7,\"result\":\"deleted\","
                     + "\"forced_refresh\":true,\"_shards\":{\"total\":10,\"successful\":5,\"failed\":0}}",
diff --git a/server/src/test/java/org/opensearch/action/explain/ExplainRequestTests.java b/server/src/test/java/org/opensearch/action/explain/ExplainRequestTests.java
index 6642f5c10522e..226ef7e39ed04 100644
--- a/server/src/test/java/org/opensearch/action/explain/ExplainRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/explain/ExplainRequestTests.java
@@ -33,10 +33,10 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.search.SearchModule;
diff --git a/server/src/test/java/org/opensearch/action/explain/ExplainResponseTests.java b/server/src/test/java/org/opensearch/action/explain/ExplainResponseTests.java
index b6918bd3590a9..f8d10128a82ad 100644
--- a/server/src/test/java/org/opensearch/action/explain/ExplainResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/explain/ExplainResponseTests.java
@@ -33,15 +33,14 @@
 package org.opensearch.action.explain;
 
 import org.apache.lucene.search.Explanation;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.RandomObjects;
@@ -114,7 +113,7 @@ public void testToXContent() throws IOException {
         );
         ExplainResponse response = new ExplainResponse(index, id, exist, explanation, getResult);
 
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
         String generatedResponse = BytesReference.bytes(builder).utf8ToString().replaceAll("\\s+", "");
diff --git a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestTests.java b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestTests.java
index 71ce15dcda568..b1602393c590c 100644
--- a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesRequestTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponseTests.java b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponseTests.java
index 222b348a3ed5e..bfd463f442da3 100644
--- a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesResponseTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.fieldcaps;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesTests.java b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesTests.java
index 0994455da232c..1f31d93997243 100644
--- a/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesTests.java
+++ b/server/src/test/java/org/opensearch/action/fieldcaps/FieldCapabilitiesTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.action.fieldcaps;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java b/server/src/test/java/org/opensearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
index 35572a11a23b9..f196ba16a2584 100644
--- a/server/src/test/java/org/opensearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
@@ -32,13 +32,12 @@
 
 package org.opensearch.action.fieldcaps;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -125,7 +124,7 @@ protected Predicate<String> getRandomFieldsExcludeFilter() {
     public void testToXContent() throws IOException {
         FieldCapabilitiesResponse response = createSimpleResponse();
 
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
         String generatedResponse = BytesReference.bytes(builder).utf8ToString();
diff --git a/server/src/test/java/org/opensearch/action/get/GetResponseTests.java b/server/src/test/java/org/opensearch/action/get/GetResponseTests.java
index 39b330fa10a7b..72190bcbe97b6 100644
--- a/server/src/test/java/org/opensearch/action/get/GetResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/get/GetResponseTests.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -48,7 +49,7 @@
 import java.util.Collections;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.index.get.GetResultTests.copyGetResult;
 import static org.opensearch.index.get.GetResultTests.mutateGetResult;
 import static org.opensearch.index.get.GetResultTests.randomGetResult;
@@ -118,7 +119,7 @@ public void testToXContent() {
                     null
                 )
             );
-            String output = Strings.toString(getResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, getResponse);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":1,\"_seq_no\":0,\"_primary_term\":1,"
                     + "\"found\":true,\"_source\":{ \"field1\" : \"value1\", \"field2\":\"value2\"},\"fields\":{\"field1\":[\"value1\"]}}",
@@ -127,7 +128,7 @@ public void testToXContent() {
         }
         {
             GetResponse getResponse = new GetResponse(new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null));
-            String output = Strings.toString(getResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, getResponse);
             assertEquals("{\"_index\":\"index\",\"_id\":\"id\",\"found\":false}", output);
         }
     }
@@ -155,7 +156,7 @@ public void testToString() {
 
     public void testEqualsAndHashcode() {
         checkEqualsAndHashCode(
-            new GetResponse(randomGetResult(XContentType.JSON).v1()),
+            new GetResponse(randomGetResult(MediaTypeRegistry.JSON).v1()),
             GetResponseTests::copyGetResponse,
             GetResponseTests::mutateGetResponse
         );
diff --git a/server/src/test/java/org/opensearch/action/get/MultiGetRequestTests.java b/server/src/test/java/org/opensearch/action/get/MultiGetRequestTests.java
index cf26117210dfb..f000b7a10a30b 100644
--- a/server/src/test/java/org/opensearch/action/get/MultiGetRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/get/MultiGetRequestTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 import org.opensearch.test.OpenSearchTestCase;
@@ -126,7 +126,7 @@ public void testXContentSerialization() throws IOException {
             MultiGetRequest expected = createTestInstance();
             XContentType xContentType = randomFrom(XContentType.values());
             BytesReference shuffled = toShuffledXContent(expected, xContentType, ToXContent.EMPTY_PARAMS, false);
-            try (XContentParser parser = createParser(XContentFactory.xContent(xContentType), shuffled)) {
+            try (XContentParser parser = createParser(xContentType.xContent(), shuffled)) {
                 MultiGetRequest actual = new MultiGetRequest();
                 actual.add(null, null, null, null, parser, true);
                 assertThat(parser.nextToken(), nullValue());
diff --git a/server/src/test/java/org/opensearch/action/get/MultiGetResponseTests.java b/server/src/test/java/org/opensearch/action/get/MultiGetResponseTests.java
index a167f41d41b66..1a626f5646c26 100644
--- a/server/src/test/java/org/opensearch/action/get/MultiGetResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/get/MultiGetResponseTests.java
@@ -31,11 +31,10 @@
 
 package org.opensearch.action.get;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -53,7 +52,7 @@ public void testFromXContent() throws IOException {
             XContentType xContentType = randomFrom(XContentType.values());
             BytesReference shuffled = toShuffledXContent(expected, xContentType, ToXContent.EMPTY_PARAMS, false);
             MultiGetResponse parsed;
-            try (XContentParser parser = createParser(XContentFactory.xContent(xContentType), shuffled)) {
+            try (XContentParser parser = createParser(xContentType.xContent(), shuffled)) {
                 parsed = MultiGetResponse.fromXContent(parser);
                 assertNull(parser.nextToken());
             }
diff --git a/server/src/test/java/org/opensearch/action/get/MultiGetShardRequestTests.java b/server/src/test/java/org/opensearch/action/get/MultiGetShardRequestTests.java
index 5bf4f50c50c63..c21d3a25e7f58 100644
--- a/server/src/test/java/org/opensearch/action/get/MultiGetShardRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/get/MultiGetShardRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.get;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.VersionType;
 import org.opensearch.search.fetch.subphase.FetchSourceContext;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/action/get/TransportGetActionTests.java b/server/src/test/java/org/opensearch/action/get/TransportGetActionTests.java
new file mode 100644
index 0000000000000..9565e219d1a78
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/get/TransportGetActionTests.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.get;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.Preference;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.opensearch.common.UUIDs.randomBase64UUID;
+
+public class TransportGetActionTests extends OpenSearchTestCase {
+
+    private static ClusterState clusterState(ReplicationType replicationType) {
+        final Index index1 = new Index("index1", randomBase64UUID());
+        return ClusterState.builder(new ClusterName(TransportGetActionTests.class.getSimpleName()))
+            .metadata(
+                new Metadata.Builder().put(
+                    new IndexMetadata.Builder(index1.getName()).settings(
+                        Settings.builder()
+                            .put("index.version.created", Version.CURRENT)
+                            .put("index.number_of_shards", 1)
+                            .put("index.number_of_replicas", 1)
+                            .put(IndexMetadata.SETTING_INDEX_UUID, index1.getUUID())
+                            .put(IndexMetadata.SETTING_REPLICATION_TYPE, replicationType)
+                    )
+                )
+            )
+            .build();
+    }
+
+    public void testShouldForcePrimaryRouting() {
+
+        Metadata metadata = clusterState(ReplicationType.SEGMENT).getMetadata();
+
+        // should return false since preference is set for request
+        assertFalse(TransportGetAction.shouldForcePrimaryRouting(metadata, true, Preference.REPLICA.type(), "index1"));
+
+        // should return false since request is not realtime
+        assertFalse(TransportGetAction.shouldForcePrimaryRouting(metadata, false, null, "index1"));
+
+        // should return true since segment replication is enabled
+        assertTrue(TransportGetAction.shouldForcePrimaryRouting(metadata, true, null, "index1"));
+
+        // should return false since index doesn't exist
+        assertFalse(TransportGetAction.shouldForcePrimaryRouting(metadata, true, null, "index3"));
+
+        metadata = clusterState(ReplicationType.DOCUMENT).getMetadata();
+
+        // should fail since document replication enabled
+        assertFalse(TransportGetAction.shouldForcePrimaryRouting(metadata, true, null, "index1"));
+
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/action/get/TransportMultiGetActionTests.java b/server/src/test/java/org/opensearch/action/get/TransportMultiGetActionTests.java
index 1184b05461025..52443e695e014 100644
--- a/server/src/test/java/org/opensearch/action/get/TransportMultiGetActionTests.java
+++ b/server/src/test/java/org/opensearch/action/get/TransportMultiGetActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.get;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.support.ActionFilters;
@@ -45,21 +44,25 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.OperationRouting;
+import org.opensearch.cluster.routing.Preference;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -68,6 +71,7 @@
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
+import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -91,32 +95,8 @@ public class TransportMultiGetActionTests extends OpenSearchTestCase {
     private static TransportMultiGetAction transportAction;
     private static TransportShardMultiGetAction shardAction;
 
-    @BeforeClass
-    public static void beforeClass() throws Exception {
-        threadPool = new TestThreadPool(TransportMultiGetActionTests.class.getSimpleName());
-
-        transportService = new TransportService(
-            Settings.EMPTY,
-            mock(Transport.class),
-            threadPool,
-            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
-            boundAddress -> DiscoveryNode.createLocal(
-                Settings.builder().put("node.name", "node1").build(),
-                boundAddress.publishAddress(),
-                randomBase64UUID()
-            ),
-            null,
-            emptySet()
-        ) {
-            @Override
-            public TaskManager getTaskManager() {
-                return taskManager;
-            }
-        };
-
-        final Index index1 = new Index("index1", randomBase64UUID());
-        final Index index2 = new Index("index2", randomBase64UUID());
-        final ClusterState clusterState = ClusterState.builder(new ClusterName(TransportMultiGetActionTests.class.getSimpleName()))
+    private static ClusterState clusterState(ReplicationType replicationType, Index index1, Index index2) throws IOException {
+        return ClusterState.builder(new ClusterName(TransportMultiGetActionTests.class.getSimpleName()))
             .metadata(
                 new Metadata.Builder().put(
                     new IndexMetadata.Builder(index1.getName()).settings(
@@ -124,6 +104,7 @@ public TaskManager getTaskManager() {
                             .put("index.version.created", Version.CURRENT)
                             .put("index.number_of_shards", 1)
                             .put("index.number_of_replicas", 1)
+                            .put(IndexMetadata.SETTING_REPLICATION_TYPE, replicationType)
                             .put(IndexMetadata.SETTING_INDEX_UUID, index1.getUUID())
                     )
                         .putMapping(
@@ -139,7 +120,7 @@ public TaskManager getTaskManager() {
                                         .endObject()
                                 ),
                                 true,
-                                XContentType.JSON
+                                MediaTypeRegistry.JSON
                             )
                         )
                 )
@@ -149,6 +130,7 @@ public TaskManager getTaskManager() {
                                 .put("index.version.created", Version.CURRENT)
                                 .put("index.number_of_shards", 1)
                                 .put("index.number_of_replicas", 1)
+                                .put(IndexMetadata.SETTING_REPLICATION_TYPE, replicationType)
                                 .put(IndexMetadata.SETTING_INDEX_UUID, index1.getUUID())
                         )
                             .putMapping(
@@ -164,12 +146,41 @@ public TaskManager getTaskManager() {
                                             .endObject()
                                     ),
                                     true,
-                                    XContentType.JSON
+                                    MediaTypeRegistry.JSON
                                 )
                             )
                     )
             )
             .build();
+    }
+
+    @BeforeClass
+    public static void beforeClass() throws Exception {
+        threadPool = new TestThreadPool(TransportMultiGetActionTests.class.getSimpleName());
+
+        transportService = new TransportService(
+            Settings.EMPTY,
+            mock(Transport.class),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> DiscoveryNode.createLocal(
+                Settings.builder().put("node.name", "node1").build(),
+                boundAddress.publishAddress(),
+                randomBase64UUID()
+            ),
+            null,
+            emptySet(),
+            NoopTracer.INSTANCE
+        ) {
+            @Override
+            public TaskManager getTaskManager() {
+                return taskManager;
+            }
+        };
+
+        final Index index1 = new Index("index1", randomBase64UUID());
+        final Index index2 = new Index("index2", randomBase64UUID());
+        ClusterState clusterState = clusterState(randomBoolean() ? ReplicationType.SEGMENT : ReplicationType.DOCUMENT, index1, index2);
 
         final ShardIterator index1ShardIterator = mock(ShardIterator.class);
         when(index1ShardIterator.shardId()).thenReturn(new ShardId(index1, randomInt()));
@@ -285,6 +296,30 @@ protected void executeShardAction(
 
     }
 
+    public void testShouldForcePrimaryRouting() throws IOException {
+        final Index index1 = new Index("index1", randomBase64UUID());
+        final Index index2 = new Index("index2", randomBase64UUID());
+        Metadata metadata = clusterState(ReplicationType.SEGMENT, index1, index2).getMetadata();
+
+        // should return false since preference is set for request
+        assertFalse(TransportMultiGetAction.shouldForcePrimaryRouting(metadata, true, Preference.REPLICA.type(), "index1"));
+
+        // should return false since request is not realtime
+        assertFalse(TransportMultiGetAction.shouldForcePrimaryRouting(metadata, false, null, "index2"));
+
+        // should return true since segment replication is enabled
+        assertTrue(TransportMultiGetAction.shouldForcePrimaryRouting(metadata, true, null, "index1"));
+
+        // should return false since index doesn't exist
+        assertFalse(TransportMultiGetAction.shouldForcePrimaryRouting(metadata, true, null, "index3"));
+
+        metadata = clusterState(ReplicationType.DOCUMENT, index1, index2).getMetadata();
+
+        // should fail since document replication enabled
+        assertFalse(TransportGetAction.shouldForcePrimaryRouting(metadata, true, null, "index1"));
+
+    }
+
     private static Task createTask() {
         return new Task(
             randomLong(),
diff --git a/server/src/test/java/org/opensearch/action/index/IndexRequestBuilderTests.java b/server/src/test/java/org/opensearch/action/index/IndexRequestBuilderTests.java
index 8ff1282dd86ff..456aab4b92e4e 100644
--- a/server/src/test/java/org/opensearch/action/index/IndexRequestBuilderTests.java
+++ b/server/src/test/java/org/opensearch/action/index/IndexRequestBuilderTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.index;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 import org.junit.After;
@@ -74,7 +74,7 @@ public void testSetSource() throws Exception {
         indexRequestBuilder.setSource(source);
         assertEquals(EXPECTED_SOURCE, XContentHelper.convertToJson(indexRequestBuilder.request().source(), true));
 
-        indexRequestBuilder.setSource(source, XContentType.JSON);
+        indexRequestBuilder.setSource(source, MediaTypeRegistry.JSON);
         assertEquals(EXPECTED_SOURCE, XContentHelper.convertToJson(indexRequestBuilder.request().source(), true));
 
         indexRequestBuilder.setSource("SomeKey", "SomeValue");
@@ -87,7 +87,7 @@ public void testSetSource() throws Exception {
         ByteArrayOutputStream docOut = new ByteArrayOutputStream();
         XContentBuilder doc = XContentFactory.jsonBuilder(docOut).startObject().field("SomeKey", "SomeValue").endObject();
         doc.close();
-        indexRequestBuilder.setSource(docOut.toByteArray(), XContentType.JSON);
+        indexRequestBuilder.setSource(docOut.toByteArray(), MediaTypeRegistry.JSON);
         assertEquals(
             EXPECTED_SOURCE,
             XContentHelper.convertToJson(indexRequestBuilder.request().source(), true, indexRequestBuilder.request().getContentType())
diff --git a/server/src/test/java/org/opensearch/action/index/IndexRequestTests.java b/server/src/test/java/org/opensearch/action/index/IndexRequestTests.java
index 21305957d802b..8a66c859bc99b 100644
--- a/server/src/test/java/org/opensearch/action/index/IndexRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/index/IndexRequestTests.java
@@ -36,15 +36,15 @@
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -99,19 +99,19 @@ public void testCreateOperationRejectsVersions() {
     public void testIndexingRejectsLongIds() {
         String id = randomAlphaOfLength(511);
         IndexRequest request = new IndexRequest("index").id(id);
-        request.source("{}", XContentType.JSON);
+        request.source("{}", MediaTypeRegistry.JSON);
         ActionRequestValidationException validate = request.validate();
         assertNull(validate);
 
         id = randomAlphaOfLength(512);
         request = new IndexRequest("index").id(id);
-        request.source("{}", XContentType.JSON);
+        request.source("{}", MediaTypeRegistry.JSON);
         validate = request.validate();
         assertNull(validate);
 
         id = randomAlphaOfLength(513);
         request = new IndexRequest("index").id(id);
-        request.source("{}", XContentType.JSON);
+        request.source("{}", MediaTypeRegistry.JSON);
         validate = request.validate();
         assertThat(validate, notNullValue());
         assertThat(validate.getMessage(), containsString("id [" + id + "] is too long, must be no longer than 512 bytes but was: 513"));
@@ -182,15 +182,15 @@ public void testIndexResponse() {
     public void testIndexRequestXContentSerialization() throws IOException {
         IndexRequest indexRequest = new IndexRequest("foo").id("1");
         boolean isRequireAlias = randomBoolean();
-        indexRequest.source("{}", XContentType.JSON);
+        indexRequest.source("{}", MediaTypeRegistry.JSON);
         indexRequest.setRequireAlias(isRequireAlias);
-        assertEquals(XContentType.JSON, indexRequest.getContentType());
+        assertEquals(MediaTypeRegistry.JSON, indexRequest.getContentType());
 
         BytesStreamOutput out = new BytesStreamOutput();
         indexRequest.writeTo(out);
         StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes);
         IndexRequest serialized = new IndexRequest(in);
-        assertEquals(XContentType.JSON, serialized.getContentType());
+        assertEquals(MediaTypeRegistry.JSON, serialized.getContentType());
         assertEquals(new BytesArray("{}"), serialized.source());
         assertEquals(isRequireAlias, serialized.isRequireAlias());
     }
@@ -215,11 +215,11 @@ public void testToStringSizeLimit() throws UnsupportedEncodingException {
         IndexRequest request = new IndexRequest("index");
 
         String source = "{\"name\":\"value\"}";
-        request.source(source, XContentType.JSON);
+        request.source(source, MediaTypeRegistry.JSON);
         assertEquals("index {[index][null], source[" + source + "]}", request.toString());
 
         source = "{\"name\":\"" + randomUnicodeOfLength(IndexRequest.MAX_SOURCE_LENGTH_IN_TOSTRING) + "\"}";
-        request.source(source, XContentType.JSON);
+        request.source(source, MediaTypeRegistry.JSON);
         int actualBytes = source.getBytes("UTF-8").length;
         assertEquals(
             "index {[index][null], source[n/a, actual length: ["
@@ -233,7 +233,7 @@ public void testToStringSizeLimit() throws UnsupportedEncodingException {
 
     public void testRejectsEmptyStringPipeline() {
         IndexRequest request = new IndexRequest("index");
-        request.source("{}", XContentType.JSON);
+        request.source("{}", MediaTypeRegistry.JSON);
         request.setPipeline("");
         ActionRequestValidationException validate = request.validate();
         assertThat(validate, notNullValue());
diff --git a/server/src/test/java/org/opensearch/action/index/IndexResponseTests.java b/server/src/test/java/org/opensearch/action/index/IndexResponseTests.java
index 25d6a60299848..8aeca8af8ce07 100644
--- a/server/src/test/java/org/opensearch/action/index/IndexResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/index/IndexResponseTests.java
@@ -34,14 +34,15 @@
 
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -57,7 +58,7 @@ public class IndexResponseTests extends OpenSearchTestCase {
     public void testToXContent() {
         {
             IndexResponse indexResponse = new IndexResponse(new ShardId("index", "index_uuid", 0), "id", 3, 17, 5, true);
-            String output = Strings.toString(indexResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, indexResponse);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":5,\"result\":\"created\",\"_shards\":null,"
                     + "\"_seq_no\":3,\"_primary_term\":17}",
@@ -68,7 +69,7 @@ public void testToXContent() {
             IndexResponse indexResponse = new IndexResponse(new ShardId("index", "index_uuid", 0), "id", -1, 17, 7, true);
             indexResponse.setForcedRefresh(true);
             indexResponse.setShardInfo(new ReplicationResponse.ShardInfo(10, 5));
-            String output = Strings.toString(indexResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, indexResponse);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":7,\"result\":\"created\","
                     + "\"forced_refresh\":true,\"_shards\":{\"total\":10,\"successful\":5,\"failed\":0}}",
diff --git a/server/src/test/java/org/opensearch/action/ingest/GetPipelineResponseTests.java b/server/src/test/java/org/opensearch/action/ingest/GetPipelineResponseTests.java
index 964be7609cbea..83ef9eb13d9bb 100644
--- a/server/src/test/java/org/opensearch/action/ingest/GetPipelineResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/GetPipelineResponseTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.PipelineConfiguration;
 import org.opensearch.test.AbstractSerializingTestCase;
 
@@ -99,6 +99,16 @@ public void testXContentDeserialization() throws IOException {
         }
     }
 
+    public void testSubsetNotEqual() throws IOException {
+        PipelineConfiguration pipeline1 = createRandomPipeline("pipe1");
+        PipelineConfiguration pipeline2 = createRandomPipeline("pipe2");
+
+        GetPipelineResponse response1 = new GetPipelineResponse(List.of(pipeline1));
+        GetPipelineResponse response2 = new GetPipelineResponse(List.of(pipeline1, pipeline2));
+        assertNotEquals(response1, response2);
+        assertNotEquals(response2, response1);
+    }
+
     @Override
     protected GetPipelineResponse doParseInstance(XContentParser parser) throws IOException {
         return GetPipelineResponse.fromXContent(parser);
@@ -133,4 +143,5 @@ protected GetPipelineResponse mutateInstance(GetPipelineResponse response) {
             throw new UncheckedIOException(e);
         }
     }
+
 }
diff --git a/server/src/test/java/org/opensearch/action/ingest/PutPipelineRequestTests.java b/server/src/test/java/org/opensearch/action/ingest/PutPipelineRequestTests.java
index 74502cbe91d16..5f75e9e0551dc 100644
--- a/server/src/test/java/org/opensearch/action/ingest/PutPipelineRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/PutPipelineRequestTests.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ingest.Pipeline;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -48,15 +49,19 @@
 public class PutPipelineRequestTests extends OpenSearchTestCase {
 
     public void testSerializationWithXContent() throws IOException {
-        PutPipelineRequest request = new PutPipelineRequest("1", new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
-        assertEquals(XContentType.JSON, request.getXContentType());
+        PutPipelineRequest request = new PutPipelineRequest(
+            "1",
+            new BytesArray("{}".getBytes(StandardCharsets.UTF_8)),
+            MediaTypeRegistry.JSON
+        );
+        assertEquals(MediaTypeRegistry.JSON, request.getMediaType());
 
         BytesStreamOutput output = new BytesStreamOutput();
         request.writeTo(output);
         StreamInput in = StreamInput.wrap(output.bytes().toBytesRef().bytes);
 
         PutPipelineRequest serialized = new PutPipelineRequest(in);
-        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals(MediaTypeRegistry.JSON, serialized.getMediaType());
         assertEquals("{}", serialized.getSource().utf8ToString());
     }
 
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentBaseResultTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentBaseResultTests.java
index 3144850f77aca..abb8cd59821c1 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentBaseResultTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentBaseResultTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.ingest;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.test.AbstractXContentTestCase;
 
@@ -43,11 +43,11 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import static org.opensearch.action.ingest.WriteableIngestDocumentTests.createRandomIngestDoc;
 import static org.opensearch.ingest.IngestDocumentMatcher.assertIngestDocument;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.opensearch.action.ingest.WriteableIngestDocumentTests.createRandomIngestDoc;
 
 public class SimulateDocumentBaseResultTests extends AbstractXContentTestCase<SimulateDocumentBaseResult> {
 
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentVerboseResultTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentVerboseResultTests.java
index 4ea1115fe4b7e..b351ce7a992f0 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentVerboseResultTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulateDocumentVerboseResultTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulateExecutionServiceTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulateExecutionServiceTests.java
index ff7b0dddb33a3..a5a082286f123 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulateExecutionServiceTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulateExecutionServiceTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.VersionType;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.CompoundProcessor;
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestParsingTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestParsingTests.java
index 36b1f8089fdea..705fb546a2fed 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestParsingTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestParsingTests.java
@@ -55,12 +55,12 @@
 import static org.opensearch.action.ingest.SimulatePipelineRequest.Fields;
 import static org.opensearch.action.ingest.SimulatePipelineRequest.SIMULATED_PIPELINE_ID;
 import static org.opensearch.ingest.IngestDocument.Metadata.ID;
+import static org.opensearch.ingest.IngestDocument.Metadata.IF_PRIMARY_TERM;
+import static org.opensearch.ingest.IngestDocument.Metadata.IF_SEQ_NO;
 import static org.opensearch.ingest.IngestDocument.Metadata.INDEX;
 import static org.opensearch.ingest.IngestDocument.Metadata.ROUTING;
 import static org.opensearch.ingest.IngestDocument.Metadata.VERSION;
 import static org.opensearch.ingest.IngestDocument.Metadata.VERSION_TYPE;
-import static org.opensearch.ingest.IngestDocument.Metadata.IF_SEQ_NO;
-import static org.opensearch.ingest.IngestDocument.Metadata.IF_PRIMARY_TERM;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestTests.java
index d33f37c5a4e40..90832bc3570d5 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineRequestTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -46,7 +46,7 @@
 public class SimulatePipelineRequestTests extends OpenSearchTestCase {
 
     public void testSerialization() throws IOException {
-        SimulatePipelineRequest request = new SimulatePipelineRequest(new BytesArray(""), XContentType.JSON);
+        SimulatePipelineRequest request = new SimulatePipelineRequest(new BytesArray(""), MediaTypeRegistry.JSON);
         // Sometimes we set an id
         if (randomBoolean()) {
             request.setId(randomAlphaOfLengthBetween(1, 10));
@@ -69,16 +69,16 @@ public void testSerialization() throws IOException {
     public void testSerializationWithXContent() throws IOException {
         SimulatePipelineRequest request = new SimulatePipelineRequest(
             new BytesArray("{}".getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
-        assertEquals(XContentType.JSON, request.getXContentType());
+        assertEquals(MediaTypeRegistry.JSON, request.getXContentType());
 
         BytesStreamOutput output = new BytesStreamOutput();
         request.writeTo(output);
         StreamInput in = StreamInput.wrap(output.bytes().toBytesRef().bytes);
 
         SimulatePipelineRequest serialized = new SimulatePipelineRequest(in);
-        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals(MediaTypeRegistry.JSON, serialized.getXContentType());
         assertEquals("{}", serialized.getSource().utf8ToString());
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineResponseTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineResponseTests.java
index 0132d38072848..0ef3cb1133537 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulatePipelineResponseTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.ingest;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/ingest/SimulateProcessorResultTests.java b/server/src/test/java/org/opensearch/action/ingest/SimulateProcessorResultTests.java
index 6fa043761882e..86dbc475cfb03 100644
--- a/server/src/test/java/org/opensearch/action/ingest/SimulateProcessorResultTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/SimulateProcessorResultTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.test.AbstractXContentTestCase;
 import org.opensearch.test.VersionUtils;
diff --git a/server/src/test/java/org/opensearch/action/ingest/WriteableIngestDocumentTests.java b/server/src/test/java/org/opensearch/action/ingest/WriteableIngestDocumentTests.java
index fc80a3787669b..76aa82735ab3d 100644
--- a/server/src/test/java/org/opensearch/action/ingest/WriteableIngestDocumentTests.java
+++ b/server/src/test/java/org/opensearch/action/ingest/WriteableIngestDocumentTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.action.ingest;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.ingest.RandomDocumentPicks;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.ingest.IngestDocument;
+import org.opensearch.ingest.RandomDocumentPicks;
 import org.opensearch.test.AbstractXContentTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -52,7 +52,7 @@
 import java.util.StringJoiner;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.ToXContent.EMPTY_PARAMS;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
 import static org.opensearch.ingest.IngestDocumentMatcher.assertIngestDocument;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
diff --git a/server/src/test/java/org/opensearch/action/main/MainActionTests.java b/server/src/test/java/org/opensearch/action/main/MainActionTests.java
index 3cbb6b3eb29bd..e6b79d2dd4d51 100644
--- a/server/src/test/java/org/opensearch/action/main/MainActionTests.java
+++ b/server/src/test/java/org/opensearch/action/main/MainActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.main;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -43,8 +42,10 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportService;
@@ -52,11 +53,11 @@
 import java.util.Collections;
 import java.util.concurrent.atomic.AtomicReference;
 
+import static org.opensearch.action.main.TransportMainAction.OVERRIDE_MAIN_RESPONSE_VERSION_KEY;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-import static org.opensearch.action.main.TransportMainAction.OVERRIDE_MAIN_RESPONSE_VERSION_KEY;
 
 public class MainActionTests extends OpenSearchTestCase {
 
@@ -111,7 +112,8 @@ public void testMainActionClusterAvailable() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         TransportMainAction action = new TransportMainAction(settings, transportService, mock(ActionFilters.class), clusterService);
         AtomicReference<MainResponse> responseRef = new AtomicReference<>();
@@ -148,7 +150,8 @@ public void testMainResponseVersionOverrideEnabledByConfigSetting() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
 
         final Settings settings = Settings.builder().put("node.name", "my-node").put(OVERRIDE_MAIN_RESPONSE_VERSION_KEY, true).build();
diff --git a/server/src/test/java/org/opensearch/action/main/MainResponseTests.java b/server/src/test/java/org/opensearch/action/main/MainResponseTests.java
index b333118c4e070..54f55afcdff45 100644
--- a/server/src/test/java/org/opensearch/action/main/MainResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/main/MainResponseTests.java
@@ -36,12 +36,11 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -134,7 +133,7 @@ public void testToXContent() throws IOException {
                 + TAGLINE
                 + "\""
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -150,8 +149,8 @@ public void toXContent_overrideMainResponseVersion() throws IOException {
         );
         XContentBuilder builder = XContentFactory.jsonBuilder();
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertTrue(Strings.toString(builder).contains("\"number\":\"" + responseVersion + "\","));
-        assertFalse(Strings.toString(builder).contains("\"distribution\":\"" + Build.CURRENT.getDistribution() + "\","));
+        assertTrue(builder.toString().contains("\"number\":\"" + responseVersion + "\","));
+        assertFalse(builder.toString().contains("\"distribution\":\"" + Build.CURRENT.getDistribution() + "\","));
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/action/resync/ResyncReplicationRequestTests.java b/server/src/test/java/org/opensearch/action/resync/ResyncReplicationRequestTests.java
index a078966e3aa80..654dbb203b38a 100644
--- a/server/src/test/java/org/opensearch/action/resync/ResyncReplicationRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/resync/ResyncReplicationRequestTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.action.resync;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/resync/TransportResyncReplicationActionTests.java b/server/src/test/java/org/opensearch/action/resync/TransportResyncReplicationActionTests.java
index a544bad4cd9e6..3bd8930064563 100644
--- a/server/src/test/java/org/opensearch/action/resync/TransportResyncReplicationActionTests.java
+++ b/server/src/test/java/org/opensearch/action/resync/TransportResyncReplicationActionTests.java
@@ -32,39 +32,44 @@
 package org.opensearch.action.resync;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.replication.PendingReplicationActions;
+import org.opensearch.action.support.replication.ReplicationMode;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.block.ClusterBlocks;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
 import org.opensearch.transport.nio.MockNioTransport;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -72,6 +77,7 @@
 import java.nio.charset.Charset;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -86,8 +92,8 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyString;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -116,7 +122,7 @@ public void testResyncDoesNotBlockOnPrimaryAction() throws Exception {
                 ClusterState.builder(clusterService.state())
                     .blocks(
                         ClusterBlocks.builder()
-                            .addGlobalBlock(NoMasterBlockService.NO_MASTER_BLOCK_ALL)
+                            .addGlobalBlock(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL)
                             .addIndexBlock(indexName, IndexMetadata.INDEX_WRITE_BLOCK)
                     )
             );
@@ -129,7 +135,8 @@ public void testResyncDoesNotBlockOnPrimaryAction() throws Exception {
                     new NetworkService(emptyList()),
                     PageCacheRecycler.NON_RECYCLING_INSTANCE,
                     new NamedWriteableRegistry(emptyList()),
-                    new NoneCircuitBreakerService()
+                    new NoneCircuitBreakerService(),
+                    NoopTracer.INSTANCE
                 )
             ) {
 
@@ -140,7 +147,8 @@ public void testResyncDoesNotBlockOnPrimaryAction() throws Exception {
                     NOOP_TRANSPORT_INTERCEPTOR,
                     x -> clusterService.localNode(),
                     null,
-                    Collections.emptySet()
+                    Collections.emptySet(),
+                    NoopTracer.INSTANCE
                 );
                 transportService.start();
                 transportService.acceptIncomingRequests();
@@ -156,23 +164,26 @@ public void testResyncDoesNotBlockOnPrimaryAction() throws Exception {
 
                 final AtomicInteger acquiredPermits = new AtomicInteger();
                 final IndexShard indexShard = mock(IndexShard.class);
+                final PendingReplicationActions replicationActions = new PendingReplicationActions(shardId, threadPool);
                 when(indexShard.indexSettings()).thenReturn(new IndexSettings(indexMetadata, Settings.EMPTY));
                 when(indexShard.shardId()).thenReturn(shardId);
                 when(indexShard.routingEntry()).thenReturn(primaryShardRouting);
                 when(indexShard.getPendingPrimaryTerm()).thenReturn(primaryTerm);
                 when(indexShard.getOperationPrimaryTerm()).thenReturn(primaryTerm);
                 when(indexShard.getActiveOperationsCount()).then(i -> acquiredPermits.get());
+                when(indexShard.getPendingReplicationActions()).thenReturn(replicationActions);
                 doAnswer(invocation -> {
                     ActionListener<Releasable> callback = (ActionListener<Releasable>) invocation.getArguments()[0];
                     acquiredPermits.incrementAndGet();
                     callback.onResponse(acquiredPermits::decrementAndGet);
                     return null;
                 }).when(indexShard).acquirePrimaryOperationPermit(any(ActionListener.class), anyString(), any(), eq(true));
+                Set<String> trackedAllocationIds = shardRoutingTable.getAllAllocationIds();
                 when(indexShard.getReplicationGroup()).thenReturn(
                     new ReplicationGroup(
                         shardRoutingTable,
                         clusterService.state().metadata().index(index).inSyncAllocationIds(shardId.id()),
-                        shardRoutingTable.getAllAllocationIds(),
+                        trackedAllocationIds,
                         0
                     )
                 );
@@ -217,4 +228,35 @@ public void testResyncDoesNotBlockOnPrimaryAction() throws Exception {
             }
         }
     }
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        final TransportResyncReplicationAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        final TransportResyncReplicationAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private TransportResyncReplicationAction createAction() {
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        return new TransportResyncReplicationAction(
+            Settings.EMPTY,
+            mock(TransportService.class),
+            clusterService,
+            mock(IndicesService.class),
+            threadPool,
+            mock(ShardStateAction.class),
+            new ActionFilters(new HashSet<>()),
+            mock(IndexingPressureService.class),
+            new SystemIndices(emptyMap())
+        );
+    }
 }
diff --git a/server/src/test/java/org/opensearch/action/search/AbstractSearchAsyncActionTests.java b/server/src/test/java/org/opensearch/action/search/AbstractSearchAsyncActionTests.java
index f4b45b9c36f96..f628bb3201452 100644
--- a/server/src/test/java/org/opensearch/action/search/AbstractSearchAsyncActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/AbstractSearchAsyncActionTests.java
@@ -32,45 +32,84 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.MatchAllQueryBuilder;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
+import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.test.InternalAggregationTestCase;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
+import org.junit.After;
+import org.junit.Before;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.UUID;
 import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiFunction;
+import java.util.stream.IntStream;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.Mockito.mock;
 
 public class AbstractSearchAsyncActionTests extends OpenSearchTestCase {
 
     private final List<Tuple<String, String>> resolvedNodes = new ArrayList<>();
     private final Set<ShardSearchContextId> releasedContexts = new CopyOnWriteArraySet<>();
+    private ExecutorService executor;
+    ThreadPool threadPool;
+
+    @Before
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        executor = Executors.newFixedThreadPool(1);
+        threadPool = new TestThreadPool(getClass().getName());
+    }
+
+    @After
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        executor.shutdown();
+        assertTrue(executor.awaitTermination(1, TimeUnit.SECONDS));
+        ThreadPool.terminate(threadPool, 5, TimeUnit.SECONDS);
+    }
 
     private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
         SearchRequest request,
@@ -79,6 +118,27 @@ private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
         final boolean controlled,
         final AtomicLong expected
     ) {
+        return createAction(
+            request,
+            results,
+            listener,
+            controlled,
+            false,
+            expected,
+            new SearchShardIterator(null, null, Collections.emptyList(), null)
+        );
+    }
+
+    private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
+        SearchRequest request,
+        ArraySearchPhaseResults<SearchPhaseResult> results,
+        ActionListener<SearchResponse> listener,
+        final boolean controlled,
+        final boolean failExecutePhaseOnShard,
+        final AtomicLong expected,
+        final SearchShardIterator... shards
+    ) {
+
         final Runnable runnable;
         final TransportSearchAction.SearchTimeProvider timeProvider;
         if (controlled) {
@@ -105,16 +165,17 @@ private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
             Collections.singletonMap("foo", new AliasFilter(new MatchAllQueryBuilder())),
             Collections.singletonMap("foo", 2.0f),
             Collections.singletonMap("name", Sets.newHashSet("bar", "baz")),
-            null,
+            executor,
             request,
             listener,
-            new GroupShardsIterator<>(Collections.singletonList(new SearchShardIterator(null, null, Collections.emptyList(), null))),
+            new GroupShardsIterator<>(Arrays.asList(shards)),
             timeProvider,
             ClusterState.EMPTY_STATE,
             null,
             results,
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
             @Override
             protected SearchPhase getNextPhase(final SearchPhaseResults<SearchPhaseResult> results, SearchPhaseContext context) {
@@ -126,7 +187,13 @@ protected void executePhaseOnShard(
                 final SearchShardIterator shardIt,
                 final SearchShardTarget shard,
                 final SearchActionListener<SearchPhaseResult> listener
-            ) {}
+            ) {
+                if (failExecutePhaseOnShard) {
+                    listener.onFailure(new ShardNotFoundException(shardIt.shardId()));
+                } else {
+                    listener.onResponse(new QuerySearchResult());
+                }
+            }
 
             @Override
             long buildTookInMillis() {
@@ -260,6 +327,53 @@ public void testSendSearchResponseDisallowPartialFailures() {
         assertEquals(requestIds, releasedContexts);
     }
 
+    public void testOnPhaseFailureAndVerifyListeners() {
+        SearchRequestStats testListener = new SearchRequestStats();
+
+        final List<SearchRequestOperationsListener> requestOperationListeners = new ArrayList<>(List.of(testListener));
+        SearchQueryThenFetchAsyncAction action = createSearchQueryThenFetchAsyncAction(requestOperationListeners);
+        action.start();
+        assertEquals(1, testListener.getPhaseCurrent(action.getSearchPhaseName()));
+        action.onPhaseFailure(new SearchPhase("test") {
+            @Override
+            public void run() {
+
+            }
+        }, "message", null);
+        assertEquals(0, testListener.getPhaseCurrent(action.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseTotal(action.getSearchPhaseName()));
+
+        SearchDfsQueryThenFetchAsyncAction searchDfsQueryThenFetchAsyncAction = createSearchDfsQueryThenFetchAsyncAction(
+            requestOperationListeners
+        );
+        searchDfsQueryThenFetchAsyncAction.start();
+        assertEquals(1, testListener.getPhaseCurrent(searchDfsQueryThenFetchAsyncAction.getSearchPhaseName()));
+        searchDfsQueryThenFetchAsyncAction.onPhaseFailure(new SearchPhase("test") {
+            @Override
+            public void run() {
+
+            }
+        }, "message", null);
+        assertEquals(0, testListener.getPhaseCurrent(action.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseTotal(action.getSearchPhaseName()));
+
+        FetchSearchPhase fetchPhase = createFetchSearchPhase();
+        ShardId shardId = new ShardId(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLength(10), randomInt());
+        SearchShardIterator searchShardIterator = new SearchShardIterator(null, shardId, Collections.emptyList(), OriginalIndices.NONE);
+        searchShardIterator.resetAndSkip();
+        action.skipShard(searchShardIterator);
+        action.executeNextPhase(action, fetchPhase);
+        assertEquals(1, testListener.getPhaseCurrent(fetchPhase.getSearchPhaseName()));
+        action.onPhaseFailure(new SearchPhase("test") {
+            @Override
+            public void run() {
+
+            }
+        }, "message", null);
+        assertEquals(0, testListener.getPhaseCurrent(fetchPhase.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseTotal(fetchPhase.getSearchPhaseName()));
+    }
+
     public void testOnPhaseFailure() {
         SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(false);
         AtomicReference<Exception> exception = new AtomicReference<>();
@@ -268,6 +382,7 @@ public void testOnPhaseFailure() {
         List<Tuple<String, String>> nodeLookups = new ArrayList<>();
         ArraySearchPhaseResults<SearchPhaseResult> phaseResults = phaseResults(requestIds, nodeLookups, 0);
         AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, phaseResults, listener, false, new AtomicLong());
+
         action.onPhaseFailure(new SearchPhase("test") {
             @Override
             public void run() {
@@ -328,6 +443,362 @@ private static ArraySearchPhaseResults<SearchPhaseResult> phaseResults(
         return phaseResults;
     }
 
+    public void testOnShardFailurePhaseDoneFailure() throws InterruptedException {
+        final Index index = new Index("test", UUID.randomUUID().toString());
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicBoolean fail = new AtomicBoolean(true);
+
+        final SearchShardIterator[] shards = IntStream.range(0, 5 + randomInt(10))
+            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
+            .toArray(SearchShardIterator[]::new);
+
+        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
+        searchRequest.setMaxConcurrentShardRequests(1);
+
+        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
+        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
+            searchRequest,
+            queryResult,
+            new ActionListener<SearchResponse>() {
+                @Override
+                public void onResponse(SearchResponse response) {
+
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    if (fail.compareAndExchange(true, false)) {
+                        try {
+                            throw new RuntimeException("Simulated exception");
+                        } finally {
+                            executor.submit(() -> latch.countDown());
+                        }
+                    }
+                }
+            },
+            false,
+            true,
+            new AtomicLong(),
+            shards
+        );
+        action.run();
+        assertTrue(latch.await(1, TimeUnit.SECONDS));
+
+        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
+        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
+        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
+        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
+        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
+        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
+        assertThat(searchResponse.getSuccessfulShards(), equalTo(0));
+    }
+
+    public void testOnShardSuccessPhaseDoneFailure() throws InterruptedException {
+        final Index index = new Index("test", UUID.randomUUID().toString());
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicBoolean fail = new AtomicBoolean(true);
+
+        final SearchShardIterator[] shards = IntStream.range(0, 5 + randomInt(10))
+            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
+            .toArray(SearchShardIterator[]::new);
+
+        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
+        searchRequest.setMaxConcurrentShardRequests(1);
+
+        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
+        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
+            searchRequest,
+            queryResult,
+            new ActionListener<SearchResponse>() {
+                @Override
+                public void onResponse(SearchResponse response) {
+                    if (fail.compareAndExchange(true, false)) {
+                        throw new RuntimeException("Simulated exception");
+                    }
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    executor.submit(() -> latch.countDown());
+                }
+            },
+            false,
+            false,
+            new AtomicLong(),
+            shards
+        );
+        action.run();
+        assertTrue(latch.await(1, TimeUnit.SECONDS));
+
+        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
+        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
+        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
+        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
+        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
+        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
+        assertThat(searchResponse.getSuccessfulShards(), equalTo(shards.length));
+    }
+
+    public void testExecutePhaseOnShardFailure() throws InterruptedException {
+        final Index index = new Index("test", UUID.randomUUID().toString());
+
+        final SearchShardIterator[] shards = IntStream.range(0, 2 + randomInt(3))
+            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
+            .toArray(SearchShardIterator[]::new);
+
+        final AtomicBoolean fail = new AtomicBoolean(true);
+        final CountDownLatch latch = new CountDownLatch(1);
+        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
+        searchRequest.setMaxConcurrentShardRequests(5);
+
+        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
+        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
+            searchRequest,
+            queryResult,
+            new ActionListener<SearchResponse>() {
+                @Override
+                public void onResponse(SearchResponse response) {}
+
+                @Override
+                public void onFailure(Exception e) {
+                    try {
+                        // We end up here only when onPhaseDone() is called (causing NPE) and
+                        // ending up in the onPhaseFailure() callback
+                        if (fail.compareAndExchange(true, false)) {
+                            assertThat(e, instanceOf(SearchPhaseExecutionException.class));
+                            throw new RuntimeException("Simulated exception");
+                        }
+                    } finally {
+                        executor.submit(() -> latch.countDown());
+                    }
+                }
+            },
+            false,
+            false,
+            new AtomicLong(),
+            shards
+        );
+        action.run();
+        assertTrue(latch.await(1, TimeUnit.SECONDS));
+
+        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
+        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
+        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
+        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
+        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
+        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
+        assertThat(searchResponse.getSuccessfulShards(), equalTo(shards.length));
+    }
+
+    public void testOnPhaseListenersWithQueryAndThenFetchType() throws InterruptedException {
+        SearchRequestStats testListener = new SearchRequestStats();
+        final List<SearchRequestOperationsListener> requestOperationListeners = new ArrayList<>(List.of(testListener));
+
+        long delay = (randomIntBetween(1, 5));
+        delay = delay * 10;
+
+        SearchQueryThenFetchAsyncAction action = createSearchQueryThenFetchAsyncAction(requestOperationListeners);
+        action.start();
+
+        // Verify queryPhase current metric
+        assertEquals(1, testListener.getPhaseCurrent(action.getSearchPhaseName()));
+        TimeUnit.MILLISECONDS.sleep(delay);
+
+        FetchSearchPhase fetchPhase = createFetchSearchPhase();
+        ShardId shardId = new ShardId(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLength(10), randomInt());
+        SearchShardIterator searchShardIterator = new SearchShardIterator(null, shardId, Collections.emptyList(), OriginalIndices.NONE);
+        searchShardIterator.resetAndSkip();
+        action.skipShard(searchShardIterator);
+        action.executeNextPhase(action, fetchPhase);
+
+        // Verify queryPhase total, current and latency metrics
+        assertEquals(0, testListener.getPhaseCurrent(action.getSearchPhaseName()));
+        assertThat(testListener.getPhaseMetric(action.getSearchPhaseName()), greaterThanOrEqualTo(delay));
+        assertEquals(1, testListener.getPhaseTotal(action.getSearchPhaseName()));
+
+        // Verify fetchPhase current metric
+        assertEquals(1, testListener.getPhaseCurrent(fetchPhase.getSearchPhaseName()));
+        TimeUnit.MILLISECONDS.sleep(delay);
+
+        ExpandSearchPhase expandPhase = createExpandSearchPhase();
+        action.executeNextPhase(fetchPhase, expandPhase);
+        TimeUnit.MILLISECONDS.sleep(delay);
+
+        // Verify fetchPhase total, current and latency metrics
+        assertThat(testListener.getPhaseMetric(fetchPhase.getSearchPhaseName()), greaterThanOrEqualTo(delay));
+        assertEquals(1, testListener.getPhaseTotal(fetchPhase.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseCurrent(fetchPhase.getSearchPhaseName()));
+
+        assertEquals(1, testListener.getPhaseCurrent(expandPhase.getSearchPhaseName()));
+
+        action.executeNextPhase(expandPhase, fetchPhase);
+
+        action.sendSearchResponse(mock(InternalSearchResponse.class), mock(String.valueOf(QuerySearchResult.class)));
+        assertThat(testListener.getPhaseMetric(expandPhase.getSearchPhaseName()), greaterThanOrEqualTo(delay));
+        assertEquals(1, testListener.getPhaseTotal(expandPhase.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseCurrent(expandPhase.getSearchPhaseName()));
+    }
+
+    public void testOnPhaseListenersWithDfsType() throws InterruptedException {
+        SearchRequestStats testListener = new SearchRequestStats();
+        final List<SearchRequestOperationsListener> requestOperationListeners = new ArrayList<>(List.of(testListener));
+
+        SearchDfsQueryThenFetchAsyncAction searchDfsQueryThenFetchAsyncAction = createSearchDfsQueryThenFetchAsyncAction(
+            requestOperationListeners
+        );
+        long delay = (randomIntBetween(1, 5));
+
+        FetchSearchPhase fetchPhase = createFetchSearchPhase();
+        searchDfsQueryThenFetchAsyncAction.start();
+        assertEquals(1, testListener.getPhaseCurrent(searchDfsQueryThenFetchAsyncAction.getSearchPhaseName()));
+        TimeUnit.MILLISECONDS.sleep(delay);
+        ShardId shardId = new ShardId(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLength(10), randomInt());
+        SearchShardIterator searchShardIterator = new SearchShardIterator(null, shardId, Collections.emptyList(), OriginalIndices.NONE);
+        searchShardIterator.resetAndSkip();
+
+        searchDfsQueryThenFetchAsyncAction.skipShard(searchShardIterator);
+        searchDfsQueryThenFetchAsyncAction.executeNextPhase(searchDfsQueryThenFetchAsyncAction, fetchPhase);
+
+        assertThat(testListener.getPhaseMetric(searchDfsQueryThenFetchAsyncAction.getSearchPhaseName()), greaterThanOrEqualTo(delay));
+        assertEquals(1, testListener.getPhaseTotal(searchDfsQueryThenFetchAsyncAction.getSearchPhaseName()));
+        assertEquals(0, testListener.getPhaseCurrent(searchDfsQueryThenFetchAsyncAction.getSearchPhaseName()));
+    }
+
+    private SearchDfsQueryThenFetchAsyncAction createSearchDfsQueryThenFetchAsyncAction(
+        List<SearchRequestOperationsListener> searchRequestOperationsListeners
+    ) {
+        SearchPhaseController controller = new SearchPhaseController(
+            writableRegistry(),
+            r -> InternalAggregationTestCase.emptyReduceContextBuilder()
+        );
+        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
+        SearchTask task = new SearchTask(0, "n/a", "n/a", () -> "test", null, Collections.emptyMap());
+        Executor executor = OpenSearchExecutors.newDirectExecutorService();
+        SearchShardIterator shards = new SearchShardIterator(null, null, Collections.emptyList(), null);
+        GroupShardsIterator<SearchShardIterator> shardsIter = new GroupShardsIterator<>(List.of(shards));
+        QueryPhaseResultConsumer resultConsumer = new QueryPhaseResultConsumer(
+            searchRequest,
+            executor,
+            new NoopCircuitBreaker(CircuitBreaker.REQUEST),
+            controller,
+            task.getProgressListener(),
+            writableRegistry(),
+            shardsIter.size(),
+            exc -> {}
+        );
+        AtomicReference<Exception> exception = new AtomicReference<>();
+        ActionListener<SearchResponse> listener = ActionListener.wrap(response -> fail("onResponse should not be called"), exception::set);
+
+        return new SearchDfsQueryThenFetchAsyncAction(
+            logger,
+            null,
+            null,
+            null,
+            null,
+            null,
+            null,
+            executor,
+            resultConsumer,
+            searchRequest,
+            listener,
+            shardsIter,
+            null,
+            null,
+            task,
+            SearchResponse.Clusters.EMPTY,
+            new SearchRequestOperationsListener.CompositeListener(searchRequestOperationsListeners, logger)
+        );
+    }
+
+    private SearchQueryThenFetchAsyncAction createSearchQueryThenFetchAsyncAction(
+        List<SearchRequestOperationsListener> searchRequestOperationsListeners
+    ) {
+        SearchPhaseController controller = new SearchPhaseController(
+            writableRegistry(),
+            r -> InternalAggregationTestCase.emptyReduceContextBuilder()
+        );
+        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
+        SearchTask task = new SearchTask(0, "n/a", "n/a", () -> "test", null, Collections.emptyMap());
+        Executor executor = OpenSearchExecutors.newDirectExecutorService();
+        SearchShardIterator shards = new SearchShardIterator(null, null, Collections.emptyList(), null);
+        GroupShardsIterator<SearchShardIterator> shardsIter = new GroupShardsIterator<>(List.of(shards));
+        QueryPhaseResultConsumer resultConsumer = new QueryPhaseResultConsumer(
+            searchRequest,
+            executor,
+            new NoopCircuitBreaker(CircuitBreaker.REQUEST),
+            controller,
+            task.getProgressListener(),
+            writableRegistry(),
+            shardsIter.size(),
+            exc -> {}
+        );
+        AtomicReference<Exception> exception = new AtomicReference<>();
+        ActionListener<SearchResponse> listener = ActionListener.wrap(response -> fail("onResponse should not be called"), exception::set);
+        return new SearchQueryThenFetchAsyncAction(
+            logger,
+            null,
+            null,
+            null,
+            null,
+            null,
+            null,
+            executor,
+            resultConsumer,
+            searchRequest,
+            listener,
+            shardsIter,
+            null,
+            null,
+            task,
+            SearchResponse.Clusters.EMPTY,
+            new SearchRequestOperationsListener.CompositeListener(searchRequestOperationsListeners, logger)
+        ) {
+            @Override
+            ShardSearchFailure[] buildShardFailures() {
+                return ShardSearchFailure.EMPTY_ARRAY;
+            }
+
+            @Override
+            public void sendSearchResponse(InternalSearchResponse internalSearchResponse, AtomicArray<SearchPhaseResult> queryResults) {
+                start();
+            }
+        };
+    }
+
+    private FetchSearchPhase createFetchSearchPhase() {
+        SearchPhaseController controller = new SearchPhaseController(
+            writableRegistry(),
+            r -> InternalAggregationTestCase.emptyReduceContextBuilder()
+        );
+        MockSearchPhaseContext mockSearchPhaseContext = new MockSearchPhaseContext(1);
+        QueryPhaseResultConsumer results = controller.newSearchPhaseResults(
+            OpenSearchExecutors.newDirectExecutorService(),
+            new NoopCircuitBreaker(CircuitBreaker.REQUEST),
+            SearchProgressListener.NOOP,
+            mockSearchPhaseContext.getRequest(),
+            1,
+            exc -> {}
+        );
+        return new FetchSearchPhase(
+            results,
+            controller,
+            null,
+            mockSearchPhaseContext,
+            (searchResponse, scrollId) -> new SearchPhase("test") {
+                @Override
+                public void run() {
+                    mockSearchPhaseContext.sendSearchResponse(searchResponse, null);
+                }
+            }
+        );
+    }
+
+    private ExpandSearchPhase createExpandSearchPhase() {
+        MockSearchPhaseContext mockSearchPhaseContext = new MockSearchPhaseContext(1);
+        InternalSearchResponse internalSearchResponse = new InternalSearchResponse(null, null, null, null, false, null, 1);
+        return new ExpandSearchPhase(mockSearchPhaseContext, internalSearchResponse, null);
+    }
+
     private static final class PhaseResult extends SearchPhaseResult {
         PhaseResult(ShardSearchContextId contextId) {
             this.contextId = contextId;
diff --git a/server/src/test/java/org/opensearch/action/search/BottomSortValuesCollectorTests.java b/server/src/test/java/org/opensearch/action/search/BottomSortValuesCollectorTests.java
index 67a151646c635..3efcadbfb320d 100644
--- a/server/src/test/java/org/opensearch/action/search/BottomSortValuesCollectorTests.java
+++ b/server/src/test/java/org/opensearch/action/search/BottomSortValuesCollectorTests.java
@@ -46,10 +46,10 @@
 import java.time.ZoneId;
 import java.util.Arrays;
 
-import static org.apache.lucene.search.TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO;
 import static org.opensearch.index.mapper.DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.apache.lucene.search.TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO;
 
 public class BottomSortValuesCollectorTests extends OpenSearchTestCase {
     public void testWithStrings() {
diff --git a/server/src/test/java/org/opensearch/action/search/CanMatchPreFilterSearchPhaseTests.java b/server/src/test/java/org/opensearch/action/search/CanMatchPreFilterSearchPhaseTests.java
index cb2ac328002c5..43029fe57d5dd 100644
--- a/server/src/test/java/org/opensearch/action/search/CanMatchPreFilterSearchPhaseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/CanMatchPreFilterSearchPhaseTests.java
@@ -33,14 +33,14 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.GroupShardsIterator;
-import org.opensearch.common.Strings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchService;
 import org.opensearch.search.SearchShardTarget;
@@ -136,7 +136,8 @@ public void run() throws IOException {
                     latch.countDown();
                 }
             },
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         );
 
         canMatchPhase.start();
@@ -227,7 +228,8 @@ public void run() throws IOException {
                     latch.countDown();
                 }
             },
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         );
 
         canMatchPhase.start();
@@ -317,7 +319,8 @@ public void sendCanMatch(
                 null,
                 new ArraySearchPhaseResults<>(iter.size()),
                 randomIntBetween(1, 32),
-                SearchResponse.Clusters.EMPTY
+                SearchResponse.Clusters.EMPTY,
+                null
             ) {
 
                 @Override
@@ -344,7 +347,8 @@ protected void executePhaseOnShard(
                     }
                 }
             },
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         );
 
         canMatchPhase.start();
@@ -428,7 +432,8 @@ public void run() {
                         latch.countDown();
                     }
                 },
-                SearchResponse.Clusters.EMPTY
+                SearchResponse.Clusters.EMPTY,
+                null
             );
 
             canMatchPhase.start();
@@ -527,7 +532,8 @@ public void run() {
                         latch.countDown();
                     }
                 },
-                SearchResponse.Clusters.EMPTY
+                SearchResponse.Clusters.EMPTY,
+                null
             );
 
             canMatchPhase.start();
diff --git a/server/src/test/java/org/opensearch/action/search/ClearScrollControllerTests.java b/server/src/test/java/org/opensearch/action/search/ClearScrollControllerTests.java
index aeb54cb8c3c0c..b171ee46dd22c 100644
--- a/server/src/test/java/org/opensearch/action/search/ClearScrollControllerTests.java
+++ b/server/src/test/java/org/opensearch/action/search/ClearScrollControllerTests.java
@@ -32,13 +32,14 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.ShardSearchContextId;
@@ -46,7 +47,6 @@
 import org.opensearch.test.VersionUtils;
 import org.opensearch.transport.NodeNotConnectedException;
 import org.opensearch.transport.Transport;
-import org.opensearch.transport.TransportResponse;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/server/src/test/java/org/opensearch/action/search/ClearScrollRequestTests.java b/server/src/test/java/org/opensearch/action/search/ClearScrollRequestTests.java
index 6e1a18aa42534..859711b2b778c 100644
--- a/server/src/test/java/org/opensearch/action/search/ClearScrollRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/search/ClearScrollRequestTests.java
@@ -32,15 +32,14 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -94,7 +93,7 @@ public void testToXContent() throws IOException {
         clearScrollRequest.addScrollId("SCROLL_ID");
         try (XContentBuilder builder = JsonXContent.contentBuilder()) {
             clearScrollRequest.toXContent(builder, ToXContent.EMPTY_PARAMS);
-            assertEquals("{\"scroll_id\":[\"SCROLL_ID\"]}", Strings.toString(builder));
+            assertEquals("{\"scroll_id\":[\"SCROLL_ID\"]}", builder.toString());
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/search/CountedCollectorTests.java b/server/src/test/java/org/opensearch/action/search/CountedCollectorTests.java
index 7da98dbb9c9b2..ee84788a634f1 100644
--- a/server/src/test/java/org/opensearch/action/search/CountedCollectorTests.java
+++ b/server/src/test/java/org/opensearch/action/search/CountedCollectorTests.java
@@ -34,7 +34,7 @@
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.dfs.DfsSearchResult;
diff --git a/server/src/test/java/org/opensearch/action/search/CreatePitControllerTests.java b/server/src/test/java/org/opensearch/action/search/CreatePitControllerTests.java
new file mode 100644
index 0000000000000..2643aa5b6db01
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/CreatePitControllerTests.java
@@ -0,0 +1,536 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.apache.lucene.search.TotalHits;
+import org.opensearch.Version;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.StepListener;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.index.query.IdsQueryBuilder;
+import org.opensearch.index.query.MatchAllQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.SearchHits;
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.internal.InternalSearchResponse;
+import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.RemoteClusterConnectionTests;
+import org.opensearch.transport.Transport;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.action.search.PitTestsUtil.getPitId;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Functional tests for various methods in create pit controller. Covers update pit phase specifically since
+ * integration tests don't cover it.
+ */
+public class CreatePitControllerTests extends OpenSearchTestCase {
+
+    DiscoveryNode node1 = null;
+    DiscoveryNode node2 = null;
+    DiscoveryNode node3 = null;
+    String pitId = null;
+    TransportSearchAction transportSearchAction = null;
+    Task task = null;
+    DiscoveryNodes nodes = null;
+    NamedWriteableRegistry namedWriteableRegistry = null;
+    SearchResponse searchResponse = null;
+    ActionListener<CreatePitResponse> createPitListener = null;
+    ClusterService clusterServiceMock = null;
+
+    private final ThreadPool threadPool = new TestThreadPool(getClass().getName());
+    Settings settings = Settings.builder().put("node.name", CreatePitControllerTests.class.getSimpleName()).build();
+    NodeClient client = new NodeClient(settings, threadPool);
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
+    }
+
+    private MockTransportService startTransport(String id, List<DiscoveryNode> knownNodes, Version version) {
+        return startTransport(id, knownNodes, version, Settings.EMPTY);
+    }
+
+    private MockTransportService startTransport(
+        final String id,
+        final List<DiscoveryNode> knownNodes,
+        final Version version,
+        final Settings settings
+    ) {
+        return RemoteClusterConnectionTests.startTransport(id, knownNodes, version, threadPool, settings);
+    }
+
+    @Before
+    public void setupData() {
+        node1 = new DiscoveryNode("node_1", buildNewFakeTransportAddress(), Version.CURRENT);
+        node2 = new DiscoveryNode("node_2", buildNewFakeTransportAddress(), Version.CURRENT);
+        node3 = new DiscoveryNode("node_3", buildNewFakeTransportAddress(), Version.CURRENT);
+        pitId = getPitId();
+        namedWriteableRegistry = new NamedWriteableRegistry(
+            Arrays.asList(
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, TermQueryBuilder.NAME, TermQueryBuilder::new),
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, MatchAllQueryBuilder.NAME, MatchAllQueryBuilder::new),
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, IdsQueryBuilder.NAME, IdsQueryBuilder::new)
+            )
+        );
+        nodes = DiscoveryNodes.builder().add(node1).add(node2).add(node3).build();
+        transportSearchAction = mock(TransportSearchAction.class);
+        task = new Task(
+            randomLong(),
+            "transport",
+            SearchAction.NAME,
+            "description",
+            new TaskId(randomLong() + ":" + randomLong()),
+            Collections.emptyMap()
+        );
+        InternalSearchResponse response = new InternalSearchResponse(
+            new SearchHits(new SearchHit[0], new TotalHits(0, TotalHits.Relation.EQUAL_TO), Float.NaN),
+            InternalAggregations.EMPTY,
+            null,
+            null,
+            false,
+            null,
+            1
+        );
+        searchResponse = new SearchResponse(
+            response,
+            null,
+            3,
+            3,
+            0,
+            100,
+            ShardSearchFailure.EMPTY_ARRAY,
+            SearchResponse.Clusters.EMPTY,
+            pitId
+        );
+        createPitListener = new ActionListener<CreatePitResponse>() {
+            @Override
+            public void onResponse(CreatePitResponse createPITResponse) {
+                assertEquals(3, createPITResponse.getTotalShards());
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throw new AssertionError(e);
+            }
+        };
+
+        clusterServiceMock = mock(ClusterService.class);
+        ClusterState state = mock(ClusterState.class);
+
+        final Settings keepAliveSettings = Settings.builder().put(CreatePitController.PIT_INIT_KEEP_ALIVE.getKey(), 30000).build();
+        when(clusterServiceMock.getSettings()).thenReturn(keepAliveSettings);
+
+        when(state.getMetadata()).thenReturn(Metadata.EMPTY_METADATA);
+        when(state.metadata()).thenReturn(Metadata.EMPTY_METADATA);
+        when(clusterServiceMock.state()).thenReturn(state);
+        when(state.getNodes()).thenReturn(nodes);
+    }
+
+    /**
+     * Test if transport call for update pit is made to all nodes present as part of PIT ID returned from phase one of create pit
+     */
+    public void testUpdatePitAfterCreatePitSuccess() throws InterruptedException {
+        List<DiscoveryNode> updateNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void updatePitContext(
+                        Transport.Connection connection,
+                        UpdatePitContextRequest request,
+                        ActionListener<UpdatePitContextResponse> listener
+                    ) {
+                        updateNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new UpdatePitContextResponse("pitid", 500000, 500000)));
+                        t.start();
+                    }
+
+                    /**
+                     * Test if cleanup request is called
+                     */
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+
+                CountDownLatch latch = new CountDownLatch(1);
+
+                CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+                request.setIndices(new String[] { "index" });
+
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                CreatePitController controller = new CreatePitController(
+                    searchTransportService,
+                    clusterServiceMock,
+                    transportSearchAction,
+                    namedWriteableRegistry,
+                    pitService
+                );
+
+                ActionListener<CreatePitResponse> updatelistener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                    @Override
+                    public void onResponse(CreatePitResponse createPITResponse) {
+                        assertEquals(3, createPITResponse.getTotalShards());
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        throw new AssertionError(e);
+                    }
+                }, latch);
+
+                StepListener<SearchResponse> createListener = new StepListener<>();
+                controller.executeCreatePit(request, task, createListener, updatelistener);
+                createListener.onResponse(searchResponse);
+                latch.await();
+                assertEquals(3, updateNodesInvoked.size());
+                assertEquals(0, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    /**
+     * If create phase results in failure, update pit phase should not proceed and propagate the exception
+     */
+    public void testUpdatePitAfterCreatePitFailure() throws InterruptedException {
+        List<DiscoveryNode> updateNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void updatePitContext(
+                        Transport.Connection connection,
+                        UpdatePitContextRequest request,
+                        ActionListener<UpdatePitContextResponse> listener
+                    ) {
+                        updateNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new UpdatePitContextResponse("pitid", 500000, 500000)));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                        t.start();
+                    }
+                };
+
+                CountDownLatch latch = new CountDownLatch(1);
+
+                CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+                request.setIndices(new String[] { "index" });
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                CreatePitController controller = new CreatePitController(
+                    searchTransportService,
+                    clusterServiceMock,
+                    transportSearchAction,
+                    namedWriteableRegistry,
+                    pitService
+                );
+
+                ActionListener<CreatePitResponse> updatelistener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                    @Override
+                    public void onResponse(CreatePitResponse createPITResponse) {
+                        throw new AssertionError("on response is called");
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        assertTrue(e.getCause().getMessage().contains("Exception occurred in phase 1"));
+                    }
+                }, latch);
+
+                StepListener<SearchResponse> createListener = new StepListener<>();
+
+                controller.executeCreatePit(request, task, createListener, updatelistener);
+                createListener.onFailure(new Exception("Exception occurred in phase 1"));
+                latch.await();
+                assertEquals(0, updateNodesInvoked.size());
+                /**
+                 * cleanup is not called on create pit phase one failure
+                 */
+                assertEquals(0, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    /**
+     * Testing that any update pit failures fails the request
+     */
+    public void testUpdatePitFailureForNodeDrop() throws InterruptedException {
+        List<DiscoveryNode> updateNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void updatePitContext(
+                        Transport.Connection connection,
+                        UpdatePitContextRequest request,
+                        ActionListener<UpdatePitContextResponse> listener
+                    ) {
+
+                        updateNodesInvoked.add(connection.getNode());
+                        if (connection.getNode().getId() == "node_3") {
+                            Thread t = new Thread(() -> listener.onFailure(new Exception("node 3 down")));
+                            t.start();
+                        } else {
+                            Thread t = new Thread(() -> listener.onResponse(new UpdatePitContextResponse("pitid", 500000, 500000)));
+                            t.start();
+                        }
+                    }
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+
+                CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+                request.setIndices(new String[] { "index" });
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                CreatePitController controller = new CreatePitController(
+                    searchTransportService,
+                    clusterServiceMock,
+                    transportSearchAction,
+                    namedWriteableRegistry,
+                    pitService
+                );
+
+                CountDownLatch latch = new CountDownLatch(1);
+
+                ActionListener<CreatePitResponse> updatelistener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                    @Override
+                    public void onResponse(CreatePitResponse createPITResponse) {
+                        throw new AssertionError("response is called");
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        assertTrue(e.getMessage().contains("node 3 down"));
+                    }
+                }, latch);
+
+                StepListener<SearchResponse> createListener = new StepListener<>();
+                controller.executeCreatePit(request, task, createListener, updatelistener);
+                createListener.onResponse(searchResponse);
+                latch.await();
+                assertEquals(3, updateNodesInvoked.size());
+                /**
+                 * check if cleanup is called for all nodes in case of update pit failure
+                 */
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testUpdatePitFailureWhereAllNodesDown() throws InterruptedException {
+        List<DiscoveryNode> updateNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void updatePitContext(
+                        Transport.Connection connection,
+                        UpdatePitContextRequest request,
+                        ActionListener<UpdatePitContextResponse> listener
+                    ) {
+                        updateNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onFailure(new Exception("node down")));
+                        t.start();
+                    }
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+                request.setIndices(new String[] { "index" });
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                CreatePitController controller = new CreatePitController(
+                    searchTransportService,
+                    clusterServiceMock,
+                    transportSearchAction,
+                    namedWriteableRegistry,
+                    pitService
+                );
+
+                CountDownLatch latch = new CountDownLatch(1);
+
+                ActionListener<CreatePitResponse> updatelistener = new LatchedActionListener<>(new ActionListener<CreatePitResponse>() {
+                    @Override
+                    public void onResponse(CreatePitResponse createPITResponse) {
+                        throw new AssertionError("response is called");
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        assertTrue(e.getMessage().contains("node down"));
+                    }
+                }, latch);
+
+                StepListener<SearchResponse> createListener = new StepListener<>();
+                controller.executeCreatePit(request, task, createListener, updatelistener);
+                createListener.onResponse(searchResponse);
+                latch.await();
+                assertEquals(3, updateNodesInvoked.size());
+                /**
+                 * check if cleanup is called for all nodes in case of update pit failure
+                 */
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/DfsQueryPhaseTests.java b/server/src/test/java/org/opensearch/action/search/DfsQueryPhaseTests.java
index d746e5639fcb1..6952841c295e2 100644
--- a/server/src/test/java/org/opensearch/action/search/DfsQueryPhaseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/DfsQueryPhaseTests.java
@@ -38,12 +38,12 @@
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
@@ -51,8 +51,8 @@
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.query.QuerySearchRequest;
 import org.opensearch.search.query.QuerySearchResult;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/search/ExpandSearchPhaseTests.java b/server/src/test/java/org/opensearch/action/search/ExpandSearchPhaseTests.java
index 8be2b9b203da6..1f5adafc5de0f 100644
--- a/server/src/test/java/org/opensearch/action/search/ExpandSearchPhaseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/ExpandSearchPhaseTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.action.search;
 
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.document.DocumentField;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.QueryBuilder;
diff --git a/server/src/test/java/org/opensearch/action/search/FetchSearchPhaseTests.java b/server/src/test/java/org/opensearch/action/search/FetchSearchPhaseTests.java
index 6c77e5f6efd5d..1eb3a44642806 100644
--- a/server/src/test/java/org/opensearch/action/search/FetchSearchPhaseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/FetchSearchPhaseTests.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
@@ -51,8 +51,8 @@
 import org.opensearch.search.fetch.ShardFetchSearchRequest;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.query.QuerySearchResult;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
 
 import java.util.concurrent.CountDownLatch;
diff --git a/server/src/test/java/org/opensearch/action/search/GetAllPitNodesResponseTests.java b/server/src/test/java/org/opensearch/action/search/GetAllPitNodesResponseTests.java
new file mode 100644
index 0000000000000..882b397575e93
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/GetAllPitNodesResponseTests.java
@@ -0,0 +1,98 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.Version;
+import org.opensearch.action.FailedNodeException;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.TransportException;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+
+public class GetAllPitNodesResponseTests extends OpenSearchTestCase {
+    protected void assertEqualInstances(GetAllPitNodesResponse expected, GetAllPitNodesResponse actual) {
+        assertNotSame(expected, actual);
+        Set<ListPitInfo> expectedPitInfos = new HashSet<>(expected.getPitInfos());
+        Set<ListPitInfo> actualPitInfos = new HashSet<>(actual.getPitInfos());
+        assertEquals(expectedPitInfos, actualPitInfos);
+
+        List<GetAllPitNodeResponse> expectedResponses = expected.getNodes();
+        List<GetAllPitNodeResponse> actualResponses = actual.getNodes();
+        assertEquals(expectedResponses.size(), actualResponses.size());
+        for (int i = 0; i < expectedResponses.size(); i++) {
+            assertEquals(expectedResponses.get(i).getNode(), actualResponses.get(i).getNode());
+            Set<ListPitInfo> expectedNodePitInfos = new HashSet<>(expectedResponses.get(i).getPitInfos());
+            Set<ListPitInfo> actualNodePitInfos = new HashSet<>(actualResponses.get(i).getPitInfos());
+            assertEquals(expectedNodePitInfos, actualNodePitInfos);
+        }
+
+        List<FailedNodeException> expectedFailures = expected.failures();
+        List<FailedNodeException> actualFailures = actual.failures();
+        assertEquals(expectedFailures.size(), actualFailures.size());
+        for (int i = 0; i < expectedFailures.size(); i++) {
+            assertEquals(expectedFailures.get(i).nodeId(), actualFailures.get(i).nodeId());
+            assertEquals(expectedFailures.get(i).getMessage(), actualFailures.get(i).getMessage());
+            assertEquals(expectedFailures.get(i).getCause().getClass(), actualFailures.get(i).getCause().getClass());
+        }
+    }
+
+    protected NamedWriteableRegistry getNamedWriteableRegistry() {
+        return new NamedWriteableRegistry(Collections.emptyList());
+    }
+
+    public void testSerialization() throws IOException {
+        GetAllPitNodesResponse response = createTestItem();
+        GetAllPitNodesResponse deserialized = copyWriteable(response, getNamedWriteableRegistry(), GetAllPitNodesResponse::new);
+        assertEqualInstances(response, deserialized);
+    }
+
+    private GetAllPitNodesResponse createTestItem() {
+        int numNodes = randomIntBetween(1, 10);
+        int numPits = randomInt(10);
+        List<ListPitInfo> candidatePitInfos = new ArrayList<>(numPits);
+        for (int i = 0; i < numNodes; i++) {
+            candidatePitInfos.add(new ListPitInfo(randomAlphaOfLength(10), randomLong(), randomLong()));
+        }
+
+        List<GetAllPitNodeResponse> responses = new ArrayList<>();
+        List<FailedNodeException> failures = new ArrayList<>();
+        for (int i = 0; i < numNodes; i++) {
+            DiscoveryNode node = new DiscoveryNode(
+                randomAlphaOfLength(10),
+                buildNewFakeTransportAddress(),
+                emptyMap(),
+                emptySet(),
+                Version.CURRENT
+            );
+            if (randomBoolean()) {
+                List<ListPitInfo> nodePitInfos = new ArrayList<>();
+                for (int j = 0; j < randomInt(numPits); j++) {
+                    nodePitInfos.add(randomFrom(candidatePitInfos));
+                }
+                responses.add(new GetAllPitNodeResponse(node, nodePitInfos));
+            } else {
+                failures.add(
+                    new FailedNodeException(node.getId(), randomAlphaOfLength(10), new TransportException(randomAlphaOfLength(10)))
+                );
+            }
+        }
+        return new GetAllPitNodesResponse(new ClusterName("test"), responses, failures);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/MockSearchPhaseContext.java b/server/src/test/java/org/opensearch/action/search/MockSearchPhaseContext.java
index e078b4a467e91..b5e1050b968ee 100644
--- a/server/src/test/java/org/opensearch/action/search/MockSearchPhaseContext.java
+++ b/server/src/test/java/org/opensearch/action/search/MockSearchPhaseContext.java
@@ -99,6 +99,11 @@ public SearchRequest getRequest() {
         return searchRequest;
     }
 
+    @Override
+    public SearchPhase getCurrentPhase() {
+        return null;
+    }
+
     @Override
     public void sendSearchResponse(InternalSearchResponse internalSearchResponse, AtomicArray<SearchPhaseResult> queryResults) {
         String scrollId = getRequest().scroll() != null ? TransportSearchHelper.buildScrollId(queryResults, Version.CURRENT) : null;
diff --git a/server/src/test/java/org/opensearch/action/search/MultiSearchActionTookTests.java b/server/src/test/java/org/opensearch/action/search/MultiSearchActionTookTests.java
index fc4bd287c5f18..94ba5b0a8768b 100644
--- a/server/src/test/java/org/opensearch/action/search/MultiSearchActionTookTests.java
+++ b/server/src/test/java/org/opensearch/action/search/MultiSearchActionTookTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.client.node.NodeClient;
@@ -46,9 +45,11 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -153,7 +154,8 @@ private TransportMultiSearchAction createTransportMultiSearchAction(boolean cont
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> DiscoveryNode.createLocal(settings, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public TaskManager getTaskManager() {
diff --git a/server/src/test/java/org/opensearch/action/search/MultiSearchRequestTests.java b/server/src/test/java/org/opensearch/action/search/MultiSearchRequestTests.java
index de80ea22071e8..7f0b658d30a6a 100644
--- a/server/src/test/java/org/opensearch/action/search/MultiSearchRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/search/MultiSearchRequestTests.java
@@ -36,19 +36,21 @@
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedRunnable;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.rest.RestRequest;
@@ -120,7 +122,7 @@ public void testFailWithUnknownKey() {
             + "{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         IllegalArgumentException ex = expectThrows(
             IllegalArgumentException.class,
@@ -134,7 +136,7 @@ public void testSimpleAddWithCarriageReturn() throws Exception {
             + "{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         MultiSearchRequest request = RestMultiSearchAction.parseRequest(restRequest, null, true);
         assertThat(request.requests().size(), equalTo(1));
@@ -152,7 +154,7 @@ public void testCancelAfterIntervalAtParentAndFewChildRequest() throws Exception
             + "{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).withParams(Collections.singletonMap("cancel_after_time_interval", "20s")).build();
         MultiSearchRequest request = RestMultiSearchAction.parseRequest(restRequest, null, true);
         assertThat(request.requests().size(), equalTo(2));
@@ -169,7 +171,7 @@ public void testOnlyParentMSearchRequestWithCancelAfterTimeIntervalParameter() t
             + "{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).withParams(Collections.singletonMap("cancel_after_time_interval", "20s")).build();
         MultiSearchRequest request = RestMultiSearchAction.parseRequest(restRequest, null, true);
         assertThat(request.requests().size(), equalTo(1));
@@ -182,7 +184,7 @@ public void testDefaultIndicesOptions() throws IOException {
             + "{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).withParams(Collections.singletonMap("ignore_unavailable", "true")).build();
         MultiSearchRequest request = RestMultiSearchAction.parseRequest(restRequest, null, true);
         assertThat(request.requests().size(), equalTo(1));
@@ -301,7 +303,7 @@ public void testResponseErrorToXContent() {
                 + "\"type\":\"illegal_state_exception\",\"reason\":\"baaaaaazzzz\"},\"status\":500"
                 + "}"
                 + "]}",
-            Strings.toString(response)
+            Strings.toString(MediaTypeRegistry.JSON, response)
         );
     }
 
@@ -315,7 +317,7 @@ public void testMsearchTerminatedByNewline() throws Exception {
         String mserchAction = StreamsUtils.copyToStringFromClasspath("/org/opensearch/action/search/simple-msearch5.json");
         RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(mserchAction.getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         IllegalArgumentException expectThrows = expectThrows(
             IllegalArgumentException.class,
@@ -326,7 +328,7 @@ public void testMsearchTerminatedByNewline() throws Exception {
         String mserchActionWithNewLine = mserchAction + "\n";
         RestRequest restRequestWithNewLine = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(mserchActionWithNewLine.getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         MultiSearchRequest msearchRequest = RestMultiSearchAction.parseRequest(restRequestWithNewLine, null, true);
         assertEquals(3, msearchRequest.requests().size());
@@ -334,14 +336,14 @@ public void testMsearchTerminatedByNewline() throws Exception {
 
     private MultiSearchRequest parseMultiSearchRequestFromString(String request) throws IOException {
         return parseMultiSearchRequest(
-            new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(request), XContentType.JSON).build()
+            new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(request), MediaTypeRegistry.JSON).build()
         );
     }
 
     private MultiSearchRequest parseMultiSearchRequestFromFile(String sample) throws IOException {
         byte[] data = StreamsUtils.copyToBytesFromClasspath(sample);
         return parseMultiSearchRequest(
-            new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data), XContentType.JSON).build()
+            new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data), MediaTypeRegistry.JSON).build()
         );
 
     }
@@ -379,10 +381,10 @@ public void testMultiLineSerialization() throws IOException {
         int iters = 16;
         for (int i = 0; i < iters; i++) {
             // The only formats that support stream separator
-            XContentType xContentType = randomFrom(XContentType.JSON, XContentType.SMILE);
+            MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.SMILE);
             MultiSearchRequest originalRequest = createMultiSearchRequest();
 
-            byte[] originalBytes = MultiSearchRequest.writeMultiLineFormat(originalRequest, xContentType.xContent());
+            byte[] originalBytes = MultiSearchRequest.writeMultiLineFormat(originalRequest, mediaType.xContent());
             MultiSearchRequest parsedRequest = new MultiSearchRequest();
             CheckedBiConsumer<SearchRequest, XContentParser, IOException> consumer = (r, p) -> {
                 SearchSourceBuilder searchSourceBuilder = SearchSourceBuilder.fromXContent(p, false);
@@ -393,7 +395,7 @@ public void testMultiLineSerialization() throws IOException {
             };
             MultiSearchRequest.readMultiLineFormat(
                 new BytesArray(originalBytes),
-                xContentType.xContent(),
+                mediaType.xContent(),
                 consumer,
                 null,
                 null,
@@ -413,7 +415,7 @@ public void testSerDeWithCancelAfterTimeIntervalParameterAndRandomVersion() thro
             + "\"cancel_after_time_interval\" : \"10s\"}\r\n{\"query\" : {\"match_all\" :{}}}\r\n";
         FakeRestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray(requestContent),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         Version version = VersionUtils.randomVersion(random());
         MultiSearchRequest originalRequest = RestMultiSearchAction.parseRequest(restRequest, null, true);
@@ -550,7 +552,7 @@ private void assertExpandWildcardsValue(IndicesOptions options, String expectedV
         try (XContentBuilder builder = JsonXContent.contentBuilder()) {
             MultiSearchRequest.writeSearchRequestParams(request, builder);
             Map<String, Object> map = XContentHelper.convertToMap(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 BytesReference.bytes(builder).streamInput(),
                 false
             );
diff --git a/server/src/test/java/org/opensearch/action/search/MultiSearchResponseTests.java b/server/src/test/java/org/opensearch/action/search/MultiSearchResponseTests.java
index fd7d1ee6f6403..e26a3cb4731da 100644
--- a/server/src/test/java/org/opensearch/action/search/MultiSearchResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/MultiSearchResponseTests.java
@@ -32,9 +32,9 @@
 package org.opensearch.action.search;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.test.AbstractXContentTestCase;
 
diff --git a/server/src/test/java/org/opensearch/action/search/PitTestsUtil.java b/server/src/test/java/org/opensearch/action/search/PitTestsUtil.java
new file mode 100644
index 0000000000000..d80e011c04332
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/PitTestsUtil.java
@@ -0,0 +1,170 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.Version;
+import org.opensearch.action.admin.cluster.state.ClusterStateRequest;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.action.admin.indices.segments.IndicesSegmentResponse;
+import org.opensearch.action.admin.indices.segments.PitSegmentsAction;
+import org.opensearch.action.admin.indices.segments.PitSegmentsRequest;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.query.IdsQueryBuilder;
+import org.opensearch.index.query.MatchAllQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.SearchShardTarget;
+import org.opensearch.search.internal.AliasFilter;
+import org.opensearch.search.internal.ShardSearchContextId;
+import org.junit.Assert;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.test.OpenSearchTestCase.between;
+import static org.opensearch.test.OpenSearchTestCase.randomAlphaOfLength;
+import static org.opensearch.test.OpenSearchTestCase.randomBoolean;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Helper class for common pit tests functions
+ */
+public class PitTestsUtil {
+    private PitTestsUtil() {}
+
+    public static QueryBuilder randomQueryBuilder() {
+        if (randomBoolean()) {
+            return new TermQueryBuilder(randomAlphaOfLength(10), randomAlphaOfLength(10));
+        } else if (randomBoolean()) {
+            return new MatchAllQueryBuilder();
+        } else {
+            return new IdsQueryBuilder().addIds(randomAlphaOfLength(10));
+        }
+    }
+
+    public static String getPitId() {
+        AtomicArray<SearchPhaseResult> array = new AtomicArray<>(3);
+        SearchAsyncActionTests.TestSearchPhaseResult testSearchPhaseResult1 = new SearchAsyncActionTests.TestSearchPhaseResult(
+            new ShardSearchContextId("a", 1),
+            null
+        );
+        testSearchPhaseResult1.setSearchShardTarget(new SearchShardTarget("node_1", new ShardId("idx", "uuid1", 2), null, null));
+        SearchAsyncActionTests.TestSearchPhaseResult testSearchPhaseResult2 = new SearchAsyncActionTests.TestSearchPhaseResult(
+            new ShardSearchContextId("b", 12),
+            null
+        );
+        testSearchPhaseResult2.setSearchShardTarget(new SearchShardTarget("node_2", new ShardId("idy", "uuid2", 42), null, null));
+        SearchAsyncActionTests.TestSearchPhaseResult testSearchPhaseResult3 = new SearchAsyncActionTests.TestSearchPhaseResult(
+            new ShardSearchContextId("c", 42),
+            null
+        );
+        testSearchPhaseResult3.setSearchShardTarget(new SearchShardTarget("node_3", new ShardId("idy", "uuid2", 43), null, null));
+        array.setOnce(0, testSearchPhaseResult1);
+        array.setOnce(1, testSearchPhaseResult2);
+        array.setOnce(2, testSearchPhaseResult3);
+
+        final Version version = Version.CURRENT;
+        final Map<String, AliasFilter> aliasFilters = new HashMap<>();
+        for (SearchPhaseResult result : array.asList()) {
+            final AliasFilter aliasFilter;
+            if (randomBoolean()) {
+                aliasFilter = new AliasFilter(randomQueryBuilder());
+            } else if (randomBoolean()) {
+                aliasFilter = new AliasFilter(randomQueryBuilder(), "alias-" + between(1, 10));
+            } else {
+                aliasFilter = AliasFilter.EMPTY;
+            }
+            if (randomBoolean()) {
+                aliasFilters.put(result.getSearchShardTarget().getShardId().getIndex().getUUID(), aliasFilter);
+            }
+        }
+        return SearchContextId.encode(array.asList(), aliasFilters, version);
+    }
+
+    public static void assertUsingGetAllPits(Client client, String id, long creationTime) throws ExecutionException, InterruptedException {
+        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
+        clusterStateRequest.local(false);
+        clusterStateRequest.clear().nodes(true).routingTable(true).indices("*");
+        ClusterStateResponse clusterStateResponse = client.admin().cluster().state(clusterStateRequest).get();
+        final List<DiscoveryNode> nodes = new LinkedList<>();
+        for (final DiscoveryNode node : clusterStateResponse.getState().nodes().getDataNodes().values()) {
+            nodes.add(node);
+        }
+        DiscoveryNode[] disNodesArr = new DiscoveryNode[nodes.size()];
+        nodes.toArray(disNodesArr);
+        GetAllPitNodesRequest getAllPITNodesRequest = new GetAllPitNodesRequest(disNodesArr);
+        ActionFuture<GetAllPitNodesResponse> execute1 = client.execute(GetAllPitsAction.INSTANCE, getAllPITNodesRequest);
+        GetAllPitNodesResponse getPitResponse = execute1.get();
+        assertTrue(getPitResponse.getPitInfos().get(0).getPitId().contains(id));
+        Assert.assertEquals(getPitResponse.getPitInfos().get(0).getCreationTime(), creationTime);
+    }
+
+    public static void assertGetAllPitsEmpty(Client client) throws ExecutionException, InterruptedException {
+        final ClusterStateRequest clusterStateRequest = new ClusterStateRequest();
+        clusterStateRequest.local(false);
+        clusterStateRequest.clear().nodes(true).routingTable(true).indices("*");
+        ClusterStateResponse clusterStateResponse = client.admin().cluster().state(clusterStateRequest).get();
+        final List<DiscoveryNode> nodes = new LinkedList<>();
+        for (final DiscoveryNode node : clusterStateResponse.getState().nodes().getDataNodes().values()) {
+            nodes.add(node);
+        }
+        DiscoveryNode[] disNodesArr = new DiscoveryNode[nodes.size()];
+        nodes.toArray(disNodesArr);
+        GetAllPitNodesRequest getAllPITNodesRequest = new GetAllPitNodesRequest(disNodesArr);
+        ActionFuture<GetAllPitNodesResponse> execute1 = client.execute(GetAllPitsAction.INSTANCE, getAllPITNodesRequest);
+        GetAllPitNodesResponse getPitResponse = execute1.get();
+        Assert.assertEquals(0, getPitResponse.getPitInfos().size());
+    }
+
+    public static void assertSegments(boolean isEmpty, String index, long expectedShardSize, Client client, String pitId) {
+        PitSegmentsRequest pitSegmentsRequest;
+        pitSegmentsRequest = new PitSegmentsRequest();
+        List<String> pitIds = new ArrayList<>();
+        pitIds.add(pitId);
+        pitSegmentsRequest.clearAndSetPitIds(pitIds);
+        IndicesSegmentResponse indicesSegmentResponse = client.execute(PitSegmentsAction.INSTANCE, pitSegmentsRequest).actionGet();
+        assertTrue(indicesSegmentResponse.getShardFailures() == null || indicesSegmentResponse.getShardFailures().length == 0);
+        assertEquals(indicesSegmentResponse.getIndices().isEmpty(), isEmpty);
+        if (!isEmpty) {
+            assertTrue(indicesSegmentResponse.getIndices().get(index) != null);
+            assertTrue(indicesSegmentResponse.getIndices().get(index).getIndex().equalsIgnoreCase(index));
+            assertEquals(expectedShardSize, indicesSegmentResponse.getIndices().get(index).getShards().size());
+        }
+    }
+
+    public static void assertSegments(boolean isEmpty, String index, long expectedShardSize, Client client) {
+        PitSegmentsRequest pitSegmentsRequest = new PitSegmentsRequest("_all");
+        IndicesSegmentResponse indicesSegmentResponse = client.execute(PitSegmentsAction.INSTANCE, pitSegmentsRequest).actionGet();
+        assertTrue(indicesSegmentResponse.getShardFailures() == null || indicesSegmentResponse.getShardFailures().length == 0);
+        assertEquals(indicesSegmentResponse.getIndices().isEmpty(), isEmpty);
+        if (!isEmpty) {
+            assertTrue(indicesSegmentResponse.getIndices().get(index) != null);
+            assertTrue(indicesSegmentResponse.getIndices().get(index).getIndex().equalsIgnoreCase(index));
+            assertEquals(expectedShardSize, indicesSegmentResponse.getIndices().get(index).getShards().size());
+        }
+    }
+
+    public static void assertSegments(boolean isEmpty, Client client) {
+        assertSegments(isEmpty, "index", 2, client);
+    }
+
+    public static void assertSegments(boolean isEmpty, Client client, String pitId) {
+        assertSegments(isEmpty, "index", 2, client, pitId);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/QueryPhaseResultConsumerTests.java b/server/src/test/java/org/opensearch/action/search/QueryPhaseResultConsumerTests.java
index 4df269a34c94e..283c9e2f238cc 100644
--- a/server/src/test/java/org/opensearch/action/search/QueryPhaseResultConsumerTests.java
+++ b/server/src/test/java/org/opensearch/action/search/QueryPhaseResultConsumerTests.java
@@ -36,13 +36,13 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.aggregations.InternalAggregation;
diff --git a/server/src/test/java/org/opensearch/action/search/SearchAsyncActionTests.java b/server/src/test/java/org/opensearch/action/search/SearchAsyncActionTests.java
index d6a0ecd0512dc..4b94b6589c6c8 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchAsyncActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchAsyncActionTests.java
@@ -32,7 +32,6 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -40,11 +39,12 @@
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.AliasFilter;
@@ -135,7 +135,8 @@ public void testSkipSearchShards() throws InterruptedException {
             null,
             new ArraySearchPhaseResults<>(shardsIter.size()),
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
 
             @Override
@@ -253,7 +254,8 @@ public void testLimitConcurrentShardRequests() throws InterruptedException {
             null,
             new ArraySearchPhaseResults<>(shardsIter.size()),
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
 
             @Override
@@ -317,7 +319,9 @@ public void testFanOutAndCollect() throws InterruptedException {
         AtomicReference<TestSearchResponse> response = new AtomicReference<>();
         ActionListener<SearchResponse> responseListener = ActionListener.wrap(
             searchResponse -> response.set((TestSearchResponse) searchResponse),
-            (e) -> { throw new AssertionError("unexpected", e); }
+            (e) -> {
+                throw new AssertionError("unexpected", e);
+            }
         );
         DiscoveryNode primaryNode = new DiscoveryNode("node_1", buildNewFakeTransportAddress(), Version.CURRENT);
         DiscoveryNode replicaNode = new DiscoveryNode("node_2", buildNewFakeTransportAddress(), Version.CURRENT);
@@ -368,7 +372,8 @@ public void sendFreeContext(Transport.Connection connection, ShardSearchContextI
             null,
             new ArraySearchPhaseResults<>(shardsIter.size()),
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
             TestSearchResponse response = new TestSearchResponse();
 
@@ -490,7 +495,8 @@ public void sendFreeContext(Transport.Connection connection, ShardSearchContextI
             null,
             new ArraySearchPhaseResults<>(shardsIter.size()),
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
             TestSearchResponse response = new TestSearchResponse();
 
@@ -603,9 +609,9 @@ public void testAllowPartialResults() throws InterruptedException {
             null,
             new ArraySearchPhaseResults<>(shardsIter.size()),
             request.getMaxConcurrentShardRequests(),
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
-
             @Override
             protected void executePhaseOnShard(
                 SearchShardIterator shardIt,
diff --git a/server/src/test/java/org/opensearch/action/search/SearchContextIdTests.java b/server/src/test/java/org/opensearch/action/search/SearchContextIdTests.java
index 24f3ca31a1992..755f7fb4de742 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchContextIdTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchContextIdTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.IdsQueryBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/action/search/SearchPhaseControllerTests.java b/server/src/test/java/org/opensearch/action/search/SearchPhaseControllerTests.java
index 2a6d6ee7e45bb..a927f733cc504 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchPhaseControllerTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchPhaseControllerTests.java
@@ -37,6 +37,7 @@
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits;
@@ -44,21 +45,21 @@
 import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
@@ -82,8 +83,8 @@
 import org.opensearch.search.suggest.completion.CompletionSuggestion;
 import org.opensearch.search.suggest.phrase.PhraseSuggestion;
 import org.opensearch.search.suggest.term.TermSuggestion;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.After;
@@ -173,27 +174,70 @@ public void testSortDocs() {
         int nShards = randomIntBetween(1, 20);
         int queryResultSize = randomBoolean() ? 0 : randomIntBetween(1, nShards * 2);
         AtomicArray<SearchPhaseResult> results = generateQueryResults(nShards, suggestions, queryResultSize, false);
-        Optional<SearchPhaseResult> first = results.asList().stream().findFirst();
-        int from = 0, size = 0;
-        if (first.isPresent()) {
-            from = first.get().queryResult().from();
-            size = first.get().queryResult().size();
+        performSortDocs(results, queryResultSize);
+    }
+
+    /**
+     * Test to verify merge shard results with SortField.Type.Int, document type Integer
+     */
+    public void testSortIntFieldDocsMerge() {
+        List<CompletionSuggestion> suggestions = new ArrayList<>();
+        for (int i = 0; i < randomIntBetween(1, 5); i++) {
+            suggestions.add(new CompletionSuggestion(randomAlphaOfLength(randomIntBetween(1, 5)), randomIntBetween(1, 20), false));
         }
-        int accumulatedLength = Math.min(queryResultSize, getTotalQueryHits(results));
-        List<CompletionSuggestion> reducedCompletionSuggestions = reducedSuggest(results);
-        for (Suggest.Suggestion<?> suggestion : reducedCompletionSuggestions) {
-            int suggestionSize = suggestion.getEntries().get(0).getOptions().size();
-            accumulatedLength += suggestionSize;
+        int nShards = randomIntBetween(1, 20);
+        int queryResultSize = randomBoolean() ? 0 : randomIntBetween(1, nShards * 2);
+        AtomicArray<SearchPhaseResult> results = generateQueryResultsWithIntSortedField(nShards, suggestions, queryResultSize, false);
+        performSortDocs(results, queryResultSize);
+    }
+
+    /**
+     * Test to verify merge shard results with different SortField.Type.
+     * Few shards with Int and few shards with Long
+     */
+    public void testSortIntLongFieldDocsMerge() {
+        List<CompletionSuggestion> suggestions = new ArrayList<>();
+        for (int i = 0; i < randomIntBetween(1, 5); i++) {
+            suggestions.add(new CompletionSuggestion(randomAlphaOfLength(randomIntBetween(1, 5)), randomIntBetween(1, 20), false));
         }
-        List<TopDocs> topDocsList = new ArrayList<>();
-        for (SearchPhaseResult result : results.asList()) {
-            QuerySearchResult queryResult = result.queryResult();
-            TopDocs topDocs = queryResult.consumeTopDocs().topDocs;
-            SearchPhaseController.setShardIndex(topDocs, result.getShardIndex());
-            topDocsList.add(topDocs);
+        int nShards = randomIntBetween(1, 20);
+        int queryResultSize = randomBoolean() ? 0 : randomIntBetween(1, nShards * 2);
+        AtomicArray<SearchPhaseResult> results = generateQueryResultsWithIntLongSortedField(nShards, suggestions, queryResultSize, false);
+        performSortDocs(results, queryResultSize);
+    }
+
+    /**
+     * Test to verify merge shard results with SortField.Type.Float, document type Float
+     */
+    public void testSortFloatFieldDocsMerge() {
+        List<CompletionSuggestion> suggestions = new ArrayList<>();
+        for (int i = 0; i < randomIntBetween(1, 5); i++) {
+            suggestions.add(new CompletionSuggestion(randomAlphaOfLength(randomIntBetween(1, 5)), randomIntBetween(1, 20), false));
         }
-        ScoreDoc[] sortedDocs = SearchPhaseController.sortDocs(true, topDocsList, from, size, reducedCompletionSuggestions).scoreDocs;
-        assertThat(sortedDocs.length, equalTo(accumulatedLength));
+        int nShards = randomIntBetween(1, 20);
+        int queryResultSize = randomBoolean() ? 0 : randomIntBetween(1, nShards * 2);
+        AtomicArray<SearchPhaseResult> results = generateQueryResultsWithFloatSortedField(nShards, suggestions, queryResultSize, false);
+        performSortDocs(results, queryResultSize);
+    }
+
+    /**
+     * Test to verify merge shard results with different SortField.Type.
+     * Few shards with Float and few shards with Double
+     */
+    public void testSortIntFloatDoubleFieldDocsMerge() {
+        List<CompletionSuggestion> suggestions = new ArrayList<>();
+        for (int i = 0; i < randomIntBetween(1, 5); i++) {
+            suggestions.add(new CompletionSuggestion(randomAlphaOfLength(randomIntBetween(1, 5)), randomIntBetween(1, 20), false));
+        }
+        int nShards = randomIntBetween(1, 20);
+        int queryResultSize = randomBoolean() ? 0 : randomIntBetween(1, nShards * 2);
+        AtomicArray<SearchPhaseResult> results = generateQueryResultsWithFloatDoubleSortedField(
+            nShards,
+            suggestions,
+            queryResultSize,
+            false
+        );
+        performSortDocs(results, queryResultSize);
     }
 
     public void testSortDocsIsIdempotent() throws Exception {
@@ -241,6 +285,30 @@ public void testSortDocsIsIdempotent() throws Exception {
         }
     }
 
+    private static void performSortDocs(AtomicArray<SearchPhaseResult> results, int queryResultSize) {
+        Optional<SearchPhaseResult> first = results.asList().stream().findFirst();
+        int from = 0, size = 0;
+        if (first.isPresent()) {
+            from = first.get().queryResult().from();
+            size = first.get().queryResult().size();
+        }
+        int accumulatedLength = Math.min(queryResultSize, getTotalQueryHits(results));
+        List<CompletionSuggestion> reducedCompletionSuggestions = reducedSuggest(results);
+        for (Suggest.Suggestion<?> suggestion : reducedCompletionSuggestions) {
+            int suggestionSize = suggestion.getEntries().get(0).getOptions().size();
+            accumulatedLength += suggestionSize;
+        }
+        List<TopDocs> topDocsList = new ArrayList<>();
+        for (SearchPhaseResult result : results.asList()) {
+            QuerySearchResult queryResult = result.queryResult();
+            TopDocs topDocs = queryResult.consumeTopDocs().topDocs;
+            SearchPhaseController.setShardIndex(topDocs, result.getShardIndex());
+            topDocsList.add(topDocs);
+        }
+        ScoreDoc[] sortedDocs = SearchPhaseController.sortDocs(true, topDocsList, from, size, reducedCompletionSuggestions).scoreDocs;
+        assertThat(sortedDocs.length, equalTo(accumulatedLength));
+    }
+
     private AtomicArray<SearchPhaseResult> generateSeededQueryResults(
         long seed,
         int nShards,
@@ -389,6 +457,128 @@ private static AtomicArray<SearchPhaseResult> generateQueryResults(
         return queryResults;
     }
 
+    private static AtomicArray<SearchPhaseResult> generateQueryResultsWithIntSortedField(
+        int nShards,
+        List<CompletionSuggestion> suggestions,
+        int searchHitsSize,
+        boolean useConstantScore
+    ) {
+        AtomicArray<SearchPhaseResult> results = generateQueryResults(nShards, suggestions, searchHitsSize, false);
+        for (int i = 0; i < results.length(); i++) {
+            int nDocs = randomIntBetween(0, searchHitsSize);
+            float maxScore = 0;
+            final TopDocs topDocs = getIntTopFieldDocs(nDocs, useConstantScore);
+            results.get(i).queryResult().topDocs(new TopDocsAndMaxScore(topDocs, maxScore), new DocValueFormat[1]);
+        }
+        return results;
+    }
+
+    private static AtomicArray<SearchPhaseResult> generateQueryResultsWithFloatSortedField(
+        int nShards,
+        List<CompletionSuggestion> suggestions,
+        int searchHitsSize,
+        boolean useConstantScore
+    ) {
+        AtomicArray<SearchPhaseResult> results = generateQueryResults(nShards, suggestions, searchHitsSize, false);
+        for (int i = 0; i < results.length(); i++) {
+            int nDocs = randomIntBetween(0, searchHitsSize);
+            float maxScore = 0;
+            final TopDocs topDocs = getFloatTopFieldDocs(nDocs, useConstantScore);
+            results.get(i).queryResult().topDocs(new TopDocsAndMaxScore(topDocs, maxScore), new DocValueFormat[1]);
+        }
+        return results;
+    }
+
+    private static AtomicArray<SearchPhaseResult> generateQueryResultsWithIntLongSortedField(
+        int nShards,
+        List<CompletionSuggestion> suggestions,
+        int searchHitsSize,
+        boolean useConstantScore
+    ) {
+        AtomicArray<SearchPhaseResult> results = generateQueryResults(nShards, suggestions, searchHitsSize, false);
+        for (int i = 0; i < results.length(); i++) {
+            int nDocs = randomIntBetween(0, searchHitsSize);
+            float maxScore = 0;
+            final TopDocs topDocs;
+            if (i % 2 == 0) {
+                topDocs = getLongTopFieldDocs(nDocs, useConstantScore);
+            } else {
+                topDocs = getIntTopFieldDocs(nDocs, useConstantScore);
+            }
+            results.get(i).queryResult().topDocs(new TopDocsAndMaxScore(topDocs, maxScore), new DocValueFormat[1]);
+        }
+        return results;
+    }
+
+    private static AtomicArray<SearchPhaseResult> generateQueryResultsWithFloatDoubleSortedField(
+        int nShards,
+        List<CompletionSuggestion> suggestions,
+        int searchHitsSize,
+        boolean useConstantScore
+    ) {
+        AtomicArray<SearchPhaseResult> results = generateQueryResults(nShards, suggestions, searchHitsSize, false);
+        for (int i = 0; i < results.length(); i++) {
+            int nDocs = randomIntBetween(0, searchHitsSize);
+            float maxScore = 0;
+            final TopDocs topDocs;
+            if (i % 2 == 0) {
+                topDocs = getFloatTopFieldDocs(nDocs, useConstantScore);
+            } else {
+                topDocs = getDoubleTopFieldDocs(nDocs, useConstantScore);
+            }
+            results.get(i).queryResult().topDocs(new TopDocsAndMaxScore(topDocs, maxScore), new DocValueFormat[1]);
+        }
+        return results;
+    }
+
+    private static TopFieldDocs getLongTopFieldDocs(int nDocs, boolean useConstantScore) {
+        FieldDoc[] fieldDocs = new FieldDoc[nDocs];
+        SortField[] sortFields = { new SortedNumericSortField("field", SortField.Type.LONG, true) };
+        float maxScore = 0;
+        for (int i = 0; i < nDocs; i++) {
+            float score = useConstantScore ? 1.0F : Math.abs(randomFloat());
+            fieldDocs[i] = new FieldDoc(i, score, new Long[] { randomLong() });
+            maxScore = Math.max(score, maxScore);
+        }
+        return new TopFieldDocs(new TotalHits(fieldDocs.length, TotalHits.Relation.EQUAL_TO), fieldDocs, sortFields);
+    }
+
+    private static TopFieldDocs getFloatTopFieldDocs(int nDocs, boolean useConstantScore) {
+        FieldDoc[] fieldDocs = new FieldDoc[nDocs];
+        SortField[] sortFields = { new SortedNumericSortField("field", SortField.Type.FLOAT, true) };
+        float maxScore = 0;
+        for (int i = 0; i < nDocs; i++) {
+            float score = useConstantScore ? 1.0F : Math.abs(randomFloat());
+            fieldDocs[i] = new FieldDoc(i, score, new Float[] { randomFloat() });
+            maxScore = Math.max(score, maxScore);
+        }
+        return new TopFieldDocs(new TotalHits(fieldDocs.length, TotalHits.Relation.EQUAL_TO), fieldDocs, sortFields);
+    }
+
+    private static TopFieldDocs getDoubleTopFieldDocs(int nDocs, boolean useConstantScore) {
+        FieldDoc[] fieldDocs = new FieldDoc[nDocs];
+        SortField[] sortFields = { new SortedNumericSortField("field", SortField.Type.DOUBLE, true) };
+        float maxScore = 0;
+        for (int i = 0; i < nDocs; i++) {
+            float score = useConstantScore ? 1.0F : Math.abs(randomFloat());
+            fieldDocs[i] = new FieldDoc(i, score, new Double[] { randomDouble() });
+            maxScore = Math.max(score, maxScore);
+        }
+        return new TopFieldDocs(new TotalHits(fieldDocs.length, TotalHits.Relation.EQUAL_TO), fieldDocs, sortFields);
+    }
+
+    private static TopFieldDocs getIntTopFieldDocs(int nDocs, boolean useConstantScore) {
+        FieldDoc[] fieldDocs = new FieldDoc[nDocs];
+        SortField[] sortFields = { new SortedNumericSortField("field", SortField.Type.INT, true) };
+        float maxScore = 0;
+        for (int i = 0; i < nDocs; i++) {
+            float score = useConstantScore ? 1.0F : Math.abs(randomFloat());
+            fieldDocs[i] = new FieldDoc(i, score, new Integer[] { randomInt() });
+            maxScore = Math.max(score, maxScore);
+        }
+        return new TopFieldDocs(new TotalHits(fieldDocs.length, TotalHits.Relation.EQUAL_TO), fieldDocs, sortFields);
+    }
+
     private static int getTotalQueryHits(AtomicArray<SearchPhaseResult> results) {
         int resultCount = 0;
         for (SearchPhaseResult shardResult : results.asList()) {
diff --git a/server/src/test/java/org/opensearch/action/search/SearchPhaseExecutionExceptionTests.java b/server/src/test/java/org/opensearch/action/search/SearchPhaseExecutionExceptionTests.java
index de17688903d2a..06b00a6a438c4 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchPhaseExecutionExceptionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchPhaseExecutionExceptionTests.java
@@ -35,19 +35,20 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.TimestampParsingException;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.InvalidIndexTemplateException;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -111,7 +112,7 @@ public void testToXContent() throws IOException {
                 + "  ]"
                 + "}"
         );
-        assertEquals(expectedJson, Strings.toString(exception));
+        assertEquals(expectedJson, Strings.toString(MediaTypeRegistry.JSON, exception));
     }
 
     public void testToAndFromXContent() throws IOException {
@@ -134,7 +135,7 @@ public void testToAndFromXContent() throws IOException {
         final String phase = randomFrom("query", "search", "other");
         SearchPhaseExecutionException actual = new SearchPhaseExecutionException(phase, "unexpected failures", shardSearchFailures);
 
-        BytesReference exceptionBytes = toShuffledXContent(actual, xContent.type(), ToXContent.EMPTY_PARAMS, randomBoolean());
+        BytesReference exceptionBytes = toShuffledXContent(actual, xContent.mediaType(), ToXContent.EMPTY_PARAMS, randomBoolean());
 
         OpenSearchException parsedException;
         try (XContentParser parser = createParser(xContent, exceptionBytes)) {
diff --git a/server/src/test/java/org/opensearch/action/search/SearchQueryThenFetchAsyncActionTests.java b/server/src/test/java/org/opensearch/action/search/SearchQueryThenFetchAsyncActionTests.java
index 4a23c4ec18951..6a22a7ea2b5e4 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchQueryThenFetchAsyncActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchQueryThenFetchAsyncActionTests.java
@@ -41,13 +41,13 @@
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.GroupShardsIterator;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
@@ -58,8 +58,8 @@
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.query.QuerySearchResult;
 import org.opensearch.search.sort.SortBuilders;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
 
 import java.util.Collections;
@@ -214,7 +214,8 @@ public void sendExecuteQuery(
             timeProvider,
             null,
             task,
-            SearchResponse.Clusters.EMPTY
+            SearchResponse.Clusters.EMPTY,
+            null
         ) {
             @Override
             protected SearchPhase getNextPhase(SearchPhaseResults<SearchPhaseResult> results, SearchPhaseContext context) {
@@ -226,6 +227,7 @@ public void run() {
                 };
             }
         };
+
         action.start();
         latch.await();
         assertThat(successfulOps.get(), equalTo(numShards));
diff --git a/server/src/test/java/org/opensearch/action/search/SearchRequestBuilderTests.java b/server/src/test/java/org/opensearch/action/search/SearchRequestBuilderTests.java
index f72dfe04ed02a..798a9b25617ce 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchRequestBuilderTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchRequestBuilderTests.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.action.search;
 
-import org.mockito.Mockito;
 import org.opensearch.client.OpenSearchClient;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.CoreMatchers.equalTo;
 
 public class SearchRequestBuilderTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/action/search/SearchRequestOperationsListenerTests.java b/server/src/test/java/org/opensearch/action/search/SearchRequestOperationsListenerTests.java
new file mode 100644
index 0000000000000..ef880043e863c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/SearchRequestOperationsListenerTests.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SearchRequestOperationsListenerTests extends OpenSearchTestCase {
+
+    public void testListenersAreExecuted() {
+        Map<SearchPhaseName, SearchRequestStats.StatsHolder> searchPhaseMap = new HashMap<>();
+
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            searchPhaseMap.put(searchPhaseName, new SearchRequestStats.StatsHolder());
+        }
+        SearchRequestOperationsListener testListener = new SearchRequestOperationsListener() {
+
+            @Override
+            public void onPhaseStart(SearchPhaseContext context) {
+                searchPhaseMap.get(context.getCurrentPhase().getSearchPhaseName()).current.inc();
+            }
+
+            @Override
+            public void onPhaseEnd(SearchPhaseContext context) {
+                searchPhaseMap.get(context.getCurrentPhase().getSearchPhaseName()).current.dec();
+                searchPhaseMap.get(context.getCurrentPhase().getSearchPhaseName()).total.inc();
+            }
+
+            @Override
+            public void onPhaseFailure(SearchPhaseContext context) {
+                searchPhaseMap.get(context.getCurrentPhase().getSearchPhaseName()).current.dec();
+            }
+        };
+
+        int totalListeners = randomIntBetween(1, 10);
+        final List<SearchRequestOperationsListener> requestOperationListeners = new ArrayList<>();
+        for (int i = 0; i < totalListeners; i++) {
+            requestOperationListeners.add(testListener);
+        }
+
+        SearchRequestOperationsListener compositeListener = new SearchRequestOperationsListener.CompositeListener(
+            requestOperationListeners,
+            logger
+        );
+
+        SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+        SearchPhase searchPhase = mock(SearchPhase.class);
+
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            when(ctx.getCurrentPhase()).thenReturn(searchPhase);
+            when(searchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            compositeListener.onPhaseStart(ctx);
+            assertEquals(totalListeners, searchPhaseMap.get(searchPhaseName).current.count());
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/SearchRequestStatsTests.java b/server/src/test/java/org/opensearch/action/search/SearchRequestStatsTests.java
new file mode 100644
index 0000000000000..f24147a8194b4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/SearchRequestStatsTests.java
@@ -0,0 +1,150 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.action.search;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Phaser;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SearchRequestStatsTests extends OpenSearchTestCase {
+    public void testSearchRequestPhaseFailure() {
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+        SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+        SearchPhase mockSearchPhase = mock(SearchPhase.class);
+        when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            testRequestStats.onPhaseStart(ctx);
+            assertEquals(1, testRequestStats.getPhaseCurrent(searchPhaseName));
+            testRequestStats.onPhaseFailure(ctx);
+            assertEquals(0, testRequestStats.getPhaseCurrent(searchPhaseName));
+        }
+    }
+
+    public void testSearchRequestStats() {
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+
+        SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+        SearchPhase mockSearchPhase = mock(SearchPhase.class);
+        when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            long tookTimeInMillis = randomIntBetween(1, 10);
+            testRequestStats.onPhaseStart(ctx);
+            long startTime = System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(tookTimeInMillis);
+            when(mockSearchPhase.getStartTimeInNanos()).thenReturn(startTime);
+            assertEquals(1, testRequestStats.getPhaseCurrent(searchPhaseName));
+            testRequestStats.onPhaseEnd(ctx);
+            assertEquals(0, testRequestStats.getPhaseCurrent(searchPhaseName));
+            assertEquals(1, testRequestStats.getPhaseTotal(searchPhaseName));
+            assertThat(testRequestStats.getPhaseMetric(searchPhaseName), greaterThanOrEqualTo(tookTimeInMillis));
+        }
+    }
+
+    public void testSearchRequestStatsOnPhaseStartConcurrently() throws InterruptedException {
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+        int numTasks = randomIntBetween(5, 50);
+        Thread[] threads = new Thread[numTasks * SearchPhaseName.values().length];
+        Phaser phaser = new Phaser(numTasks * SearchPhaseName.values().length + 1);
+        CountDownLatch countDownLatch = new CountDownLatch(numTasks * SearchPhaseName.values().length);
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+            SearchPhase mockSearchPhase = mock(SearchPhase.class);
+            when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            for (int i = 0; i < numTasks; i++) {
+                threads[i] = new Thread(() -> {
+                    phaser.arriveAndAwaitAdvance();
+                    testRequestStats.onPhaseStart(ctx);
+                    countDownLatch.countDown();
+                });
+                threads[i].start();
+            }
+        }
+        phaser.arriveAndAwaitAdvance();
+        countDownLatch.await();
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            assertEquals(numTasks, testRequestStats.getPhaseCurrent(searchPhaseName));
+        }
+    }
+
+    public void testSearchRequestStatsOnPhaseEndConcurrently() throws InterruptedException {
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+        int numTasks = randomIntBetween(5, 50);
+        Thread[] threads = new Thread[numTasks * SearchPhaseName.values().length];
+        Phaser phaser = new Phaser(numTasks * SearchPhaseName.values().length + 1);
+        CountDownLatch countDownLatch = new CountDownLatch(numTasks * SearchPhaseName.values().length);
+        Map<SearchPhaseName, Long> searchPhaseNameLongMap = new HashMap<>();
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+            SearchPhase mockSearchPhase = mock(SearchPhase.class);
+            when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            long tookTimeInMillis = randomIntBetween(1, 10);
+            long startTime = System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(tookTimeInMillis);
+            when(mockSearchPhase.getStartTimeInNanos()).thenReturn(startTime);
+            for (int i = 0; i < numTasks; i++) {
+                threads[i] = new Thread(() -> {
+                    phaser.arriveAndAwaitAdvance();
+                    testRequestStats.onPhaseEnd(ctx);
+                    countDownLatch.countDown();
+                });
+                threads[i].start();
+            }
+            searchPhaseNameLongMap.put(searchPhaseName, tookTimeInMillis);
+        }
+        phaser.arriveAndAwaitAdvance();
+        countDownLatch.await();
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            assertEquals(numTasks, testRequestStats.getPhaseTotal(searchPhaseName));
+            assertThat(
+                testRequestStats.getPhaseMetric(searchPhaseName),
+                greaterThanOrEqualTo((searchPhaseNameLongMap.get(searchPhaseName) * numTasks))
+            );
+        }
+    }
+
+    public void testSearchRequestStatsOnPhaseFailureConcurrently() throws InterruptedException {
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+        int numTasks = randomIntBetween(5, 50);
+        Thread[] threads = new Thread[numTasks * SearchPhaseName.values().length];
+        Phaser phaser = new Phaser(numTasks * SearchPhaseName.values().length + 1);
+        CountDownLatch countDownLatch = new CountDownLatch(numTasks * SearchPhaseName.values().length);
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+            SearchPhase mockSearchPhase = mock(SearchPhase.class);
+            when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            for (int i = 0; i < numTasks; i++) {
+                threads[i] = new Thread(() -> {
+                    phaser.arriveAndAwaitAdvance();
+                    testRequestStats.onPhaseStart(ctx);
+                    testRequestStats.onPhaseFailure(ctx);
+                    countDownLatch.countDown();
+                });
+                threads[i].start();
+            }
+        }
+        phaser.arriveAndAwaitAdvance();
+        countDownLatch.await();
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            assertEquals(0, testRequestStats.getPhaseCurrent(searchPhaseName));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/SearchRequestTests.java b/server/src/test/java/org/opensearch/action/search/SearchRequestTests.java
index 19544af63944c..7e6dfcc9ff645 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchRequestTests.java
@@ -36,16 +36,16 @@
 import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.ArrayUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.AbstractSearchTestCase;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.builder.PointInTimeBuilder;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/action/search/SearchResponseMergerTests.java b/server/src/test/java/org/opensearch/action/search/SearchResponseMergerTests.java
index 3f60432140425..1004965c0d50e 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchResponseMergerTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchResponseMergerTests.java
@@ -38,9 +38,9 @@
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.search.TransportSearchAction.SearchTimeProvider;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.text.Text;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
diff --git a/server/src/test/java/org/opensearch/action/search/SearchResponseTests.java b/server/src/test/java/org/opensearch/action/search/SearchResponseTests.java
index 4a68503b6c3f8..097e922147698 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchResponseTests.java
@@ -35,17 +35,26 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.rest.action.search.RestSearchAction;
+import org.opensearch.search.GenericSearchExtBuilder;
+import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.SearchHitsTests;
@@ -57,8 +66,8 @@
 import org.opensearch.search.profile.SearchProfileShardResultsTests;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.search.suggest.SuggestTests;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
 
@@ -66,8 +75,8 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.UUID;
 
-import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonMap;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
@@ -78,11 +87,25 @@ public class SearchResponseTests extends OpenSearchTestCase {
     static {
         List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(InternalAggregationTestCase.getDefaultNamedXContents());
         namedXContents.addAll(SuggestTests.getDefaultNamedXContents());
+        namedXContents.add(
+            new NamedXContentRegistry.Entry(SearchExtBuilder.class, DummySearchExtBuilder.DUMMY_FIELD, DummySearchExtBuilder::parse)
+        );
         xContentRegistry = new NamedXContentRegistry(namedXContents);
     }
 
     private final NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(
-        new SearchModule(Settings.EMPTY, emptyList()).getNamedWriteables()
+        new SearchModule(Settings.EMPTY, List.of(new SearchPlugin() {
+            @Override
+            public List<SearchExtSpec<?>> getSearchExts() {
+                return List.of(
+                    new SearchExtSpec<>(
+                        DummySearchExtBuilder.DUMMY_FIELD,
+                        DummySearchExtBuilder::new,
+                        parser -> DummySearchExtBuilder.parse(parser)
+                    )
+                );
+            }
+        })).getNamedWriteables()
     );
     private AggregationsTests aggregationsTests = new AggregationsTests();
 
@@ -117,6 +140,14 @@ private SearchResponse createMinimalTestItem() {
      * if minimal is set, don't include search hits, aggregations, suggest etc... to make test simpler
      */
     private SearchResponse createTestItem(boolean minimal, ShardSearchFailure... shardSearchFailures) {
+        return createTestItem(minimal, Collections.emptyList(), shardSearchFailures);
+    }
+
+    public SearchResponse createTestItem(
+        boolean minimal,
+        List<SearchExtBuilder> searchExtBuilders,
+        ShardSearchFailure... shardSearchFailures
+    ) {
         boolean timedOut = randomBoolean();
         Boolean terminatedEarly = randomBoolean() ? null : randomBoolean();
         int numReducePhases = randomIntBetween(1, 10);
@@ -137,7 +168,8 @@ private SearchResponse createTestItem(boolean minimal, ShardSearchFailure... sha
                 profileShardResults,
                 timedOut,
                 terminatedEarly,
-                numReducePhases
+                numReducePhases,
+                searchExtBuilders
             );
         } else {
             internalSearchResponse = InternalSearchResponse.empty();
@@ -151,7 +183,8 @@ private SearchResponse createTestItem(boolean minimal, ShardSearchFailure... sha
             skippedShards,
             tookInMillis,
             shardSearchFailures,
-            randomBoolean() ? randomClusters() : SearchResponse.Clusters.EMPTY
+            randomBoolean() ? randomClusters() : SearchResponse.Clusters.EMPTY,
+            null
         );
     }
 
@@ -170,6 +203,32 @@ public void testFromXContent() throws IOException {
         doFromXContentTestWithRandomFields(createTestItem(), false);
     }
 
+    public void testFromXContentWithSearchExtBuilders() throws IOException {
+        doFromXContentTestWithRandomFields(createTestItem(false, List.of(new DummySearchExtBuilder(UUID.randomUUID().toString()))), false);
+    }
+
+    public void testFromXContentWithUnregisteredSearchExtBuilders() throws IOException {
+        List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(InternalAggregationTestCase.getDefaultNamedXContents());
+        namedXContents.addAll(SuggestTests.getDefaultNamedXContents());
+        String dummyId = UUID.randomUUID().toString();
+        String fakeId = UUID.randomUUID().toString();
+        List<SearchExtBuilder> extBuilders = List.of(new DummySearchExtBuilder(dummyId), new FakeSearchExtBuilder(fakeId));
+        SearchResponse response = createTestItem(false, extBuilders);
+        MediaType xcontentType = randomFrom(XContentType.values());
+        boolean humanReadable = randomBoolean();
+        final ToXContent.Params params = new ToXContent.MapParams(singletonMap(RestSearchAction.TYPED_KEYS_PARAM, "true"));
+        BytesReference originalBytes = toShuffledXContent(response, xcontentType, params, humanReadable);
+        XContentParser parser = createParser(new NamedXContentRegistry(namedXContents), xcontentType.xContent(), originalBytes);
+        SearchResponse parsed = SearchResponse.fromXContent(parser);
+        assertEquals(extBuilders.size(), response.getInternalResponse().getSearchExtBuilders().size());
+
+        List<SearchExtBuilder> actual = parsed.getInternalResponse().getSearchExtBuilders();
+        assertEquals(extBuilders.size(), actual.size());
+        for (int i = 0; i < actual.size(); i++) {
+            assertTrue(actual.get(0) instanceof GenericSearchExtBuilder);
+        }
+    }
+
     /**
      * This test adds random fields and objects to the xContent rendered out to
      * ensure we can parse it back to be forward compatible with additions to
@@ -180,8 +239,8 @@ public void testFromXContentWithRandomFields() throws IOException {
         doFromXContentTestWithRandomFields(createMinimalTestItem(), true);
     }
 
-    private void doFromXContentTestWithRandomFields(SearchResponse response, boolean addRandomFields) throws IOException {
-        XContentType xcontentType = randomFrom(XContentType.values());
+    public void doFromXContentTestWithRandomFields(SearchResponse response, boolean addRandomFields) throws IOException {
+        MediaType xcontentType = randomFrom(XContentType.values());
         boolean humanReadable = randomBoolean();
         final ToXContent.Params params = new ToXContent.MapParams(singletonMap(RestSearchAction.TYPED_KEYS_PARAM, "true"));
         BytesReference originalBytes = toShuffledXContent(response, xcontentType, params, humanReadable);
@@ -243,6 +302,7 @@ public void testToXContent() {
         SearchHit hit = new SearchHit(1, "id1", Collections.emptyMap(), Collections.emptyMap());
         hit.score(2.0f);
         SearchHit[] hits = new SearchHit[] { hit };
+        String dummyId = UUID.randomUUID().toString();
         {
             SearchResponse response = new SearchResponse(
                 new InternalSearchResponse(
@@ -252,7 +312,8 @@ public void testToXContent() {
                     null,
                     false,
                     null,
-                    1
+                    1,
+                    List.of(new DummySearchExtBuilder(dummyId))
                 ),
                 null,
                 0,
@@ -260,7 +321,8 @@ public void testToXContent() {
                 0,
                 0,
                 ShardSearchFailure.EMPTY_ARRAY,
-                SearchResponse.Clusters.EMPTY
+                SearchResponse.Clusters.EMPTY,
+                null
             );
             StringBuilder expectedString = new StringBuilder();
             expectedString.append("{");
@@ -278,11 +340,17 @@ public void testToXContent() {
                 {
                     expectedString.append("{\"total\":{\"value\":100,\"relation\":\"eq\"},");
                     expectedString.append("\"max_score\":1.5,");
-                    expectedString.append("\"hits\":[{\"_id\":\"id1\",\"_score\":2.0}]}");
+                    expectedString.append("\"hits\":[{\"_id\":\"id1\",\"_score\":2.0}]},");
+                }
+                expectedString.append("\"ext\":");
+                {
+                    expectedString.append("{\"dummy\":\"" + dummyId + "\"}");
                 }
             }
             expectedString.append("}");
-            assertEquals(expectedString.toString(), Strings.toString(response));
+            assertEquals(expectedString.toString(), Strings.toString(MediaTypeRegistry.JSON, response));
+            List<SearchExtBuilder> searchExtBuilders = response.getInternalResponse().getSearchExtBuilders();
+            assertEquals(1, searchExtBuilders.size());
         }
         {
             SearchResponse response = new SearchResponse(
@@ -329,7 +397,7 @@ public void testToXContent() {
                 }
             }
             expectedString.append("}");
-            assertEquals(expectedString.toString(), Strings.toString(response));
+            assertEquals(expectedString.toString(), Strings.toString(MediaTypeRegistry.JSON, response));
         }
     }
 
@@ -350,6 +418,48 @@ public void testSerialization() throws IOException {
         assertEquals(searchResponse.getClusters(), deserialized.getClusters());
     }
 
+    public void testSerializationWithSearchExtBuilders() throws IOException {
+        String id = UUID.randomUUID().toString();
+        SearchResponse searchResponse = createTestItem(false, List.of(new DummySearchExtBuilder(id)));
+        SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.CURRENT);
+        if (searchResponse.getHits().getTotalHits() == null) {
+            assertNull(deserialized.getHits().getTotalHits());
+        } else {
+            assertEquals(searchResponse.getHits().getTotalHits().value, deserialized.getHits().getTotalHits().value);
+            assertEquals(searchResponse.getHits().getTotalHits().relation, deserialized.getHits().getTotalHits().relation);
+        }
+        assertEquals(searchResponse.getHits().getHits().length, deserialized.getHits().getHits().length);
+        assertEquals(searchResponse.getNumReducePhases(), deserialized.getNumReducePhases());
+        assertEquals(searchResponse.getFailedShards(), deserialized.getFailedShards());
+        assertEquals(searchResponse.getTotalShards(), deserialized.getTotalShards());
+        assertEquals(searchResponse.getSkippedShards(), deserialized.getSkippedShards());
+        assertEquals(searchResponse.getClusters(), deserialized.getClusters());
+        assertEquals(
+            searchResponse.getInternalResponse().getSearchExtBuilders().get(0),
+            deserialized.getInternalResponse().getSearchExtBuilders().get(0)
+        );
+    }
+
+    public void testSerializationWithSearchExtBuildersOnUnsupportedWriterVersion() throws IOException {
+        String id = UUID.randomUUID().toString();
+        SearchResponse searchResponse = createTestItem(false, List.of(new DummySearchExtBuilder(id)));
+        SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.V_2_9_0);
+        if (searchResponse.getHits().getTotalHits() == null) {
+            assertNull(deserialized.getHits().getTotalHits());
+        } else {
+            assertEquals(searchResponse.getHits().getTotalHits().value, deserialized.getHits().getTotalHits().value);
+            assertEquals(searchResponse.getHits().getTotalHits().relation, deserialized.getHits().getTotalHits().relation);
+        }
+        assertEquals(searchResponse.getHits().getHits().length, deserialized.getHits().getHits().length);
+        assertEquals(searchResponse.getNumReducePhases(), deserialized.getNumReducePhases());
+        assertEquals(searchResponse.getFailedShards(), deserialized.getFailedShards());
+        assertEquals(searchResponse.getTotalShards(), deserialized.getTotalShards());
+        assertEquals(searchResponse.getSkippedShards(), deserialized.getSkippedShards());
+        assertEquals(searchResponse.getClusters(), deserialized.getClusters());
+        assertEquals(1, searchResponse.getInternalResponse().getSearchExtBuilders().size());
+        assertTrue(deserialized.getInternalResponse().getSearchExtBuilders().isEmpty());
+    }
+
     public void testToXContentEmptyClusters() throws IOException {
         SearchResponse searchResponse = new SearchResponse(
             InternalSearchResponse.empty(),
@@ -362,8 +472,93 @@ public void testToXContentEmptyClusters() throws IOException {
             SearchResponse.Clusters.EMPTY
         );
         SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.CURRENT);
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         deserialized.getClusters().toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals(0, Strings.toString(builder).length());
+        assertEquals(0, builder.toString().length());
+    }
+
+    static class DummySearchExtBuilder extends SearchExtBuilder {
+
+        static ParseField DUMMY_FIELD = new ParseField("dummy");
+
+        protected final String id;
+
+        public DummySearchExtBuilder(String id) {
+            assertNotNull(id);
+            this.id = id;
+        }
+
+        public DummySearchExtBuilder(StreamInput in) throws IOException {
+            this.id = in.readString();
+        }
+
+        public String getId() {
+            return this.id;
+        }
+
+        @Override
+        public String getWriteableName() {
+            return DUMMY_FIELD.getPreferredName();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(this.id);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.field("dummy", id);
+        }
+
+        @Override
+        public int hashCode() {
+            return 0;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+
+            if (!(obj instanceof DummySearchExtBuilder)) {
+                return false;
+            }
+
+            return this.id.equals(((DummySearchExtBuilder) obj).getId());
+        }
+
+        public static DummySearchExtBuilder parse(XContentParser parser) throws IOException {
+            String id;
+            XContentParser.Token token = parser.currentToken();
+            if (token == XContentParser.Token.VALUE_STRING) {
+                id = parser.text();
+            } else {
+                throw new ParsingException(parser.getTokenLocation(), "Expected a VALUE_STRING but got " + token);
+            }
+            if (id == null) {
+                throw new ParsingException(parser.getTokenLocation(), "no id specified for " + DUMMY_FIELD.getPreferredName());
+            }
+            return new DummySearchExtBuilder(id);
+        }
+    }
+
+    static class FakeSearchExtBuilder extends DummySearchExtBuilder {
+        static ParseField DUMMY_FIELD = new ParseField("fake");
+
+        public FakeSearchExtBuilder(String id) {
+            super(id);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(DUMMY_FIELD.getPreferredName());
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.field(DUMMY_FIELD.getPreferredName(), id);
+        }
     }
 }
diff --git a/server/src/test/java/org/opensearch/action/search/SearchScrollAsyncActionTests.java b/server/src/test/java/org/opensearch/action/search/SearchScrollAsyncActionTests.java
index b25d6815f0f1d..3653f05936cf1 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchScrollAsyncActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchScrollAsyncActionTests.java
@@ -32,14 +32,14 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
diff --git a/server/src/test/java/org/opensearch/action/search/SearchScrollRequestTests.java b/server/src/test/java/org/opensearch/action/search/SearchScrollRequestTests.java
index 4292922bedbd9..f393b7e9eba05 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchScrollRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchScrollRequestTests.java
@@ -32,19 +32,18 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.internal.InternalScrollSearchRequest;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.test.OpenSearchTestCase;
@@ -120,7 +119,7 @@ public void testToXContent() throws IOException {
         searchScrollRequest.scroll("1m");
         try (XContentBuilder builder = JsonXContent.contentBuilder()) {
             searchScrollRequest.toXContent(builder, ToXContent.EMPTY_PARAMS);
-            assertEquals("{\"scroll_id\":\"SCROLL_ID\",\"scroll\":\"1m\"}", Strings.toString(builder));
+            assertEquals("{\"scroll_id\":\"SCROLL_ID\",\"scroll\":\"1m\"}", builder.toString());
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/search/SearchShardIteratorTests.java b/server/src/test/java/org/opensearch/action/search/SearchShardIteratorTests.java
index e1a75b3af9f28..1d84b387d2051 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchShardIteratorTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchShardIteratorTests.java
@@ -36,10 +36,10 @@
 import org.opensearch.action.OriginalIndicesTests;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.cluster.routing.GroupShardsIteratorTests;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchShardTarget;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/action/search/SearchShardTests.java b/server/src/test/java/org/opensearch/action/search/SearchShardTests.java
index a50d5685ef5d5..15b44b4e2be29 100644
--- a/server/src/test/java/org/opensearch/action/search/SearchShardTests.java
+++ b/server/src/test/java/org/opensearch/action/search/SearchShardTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.search;
 
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/action/search/ShardSearchFailureTests.java b/server/src/test/java/org/opensearch/action/search/ShardSearchFailureTests.java
index ea5c2af84a62a..0ad3b5b0ed243 100644
--- a/server/src/test/java/org/opensearch/action/search/ShardSearchFailureTests.java
+++ b/server/src/test/java/org/opensearch/action/search/ShardSearchFailureTests.java
@@ -34,20 +34,21 @@
 
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 
 public class ShardSearchFailureTests extends OpenSearchTestCase {
@@ -124,7 +125,7 @@ public void testToXContent() throws IOException {
             new ParsingException(0, 0, "some message", null),
             new SearchShardTarget("nodeId", new ShardId(new Index("indexName", "indexUuid"), 123), null, OriginalIndices.NONE)
         );
-        BytesReference xContent = toXContent(failure, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(failure, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             "{\"shard\":123,"
                 + "\"index\":\"indexName\","
@@ -145,7 +146,7 @@ public void testToXContentWithClusterAlias() throws IOException {
             new ParsingException(0, 0, "some message", null),
             new SearchShardTarget("nodeId", new ShardId(new Index("indexName", "indexUuid"), 123), "cluster1", OriginalIndices.NONE)
         );
-        BytesReference xContent = toXContent(failure, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(failure, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             "{\"shard\":123,"
                 + "\"index\":\"cluster1:indexName\","
diff --git a/server/src/test/java/org/opensearch/action/search/TransportDeletePitActionTests.java b/server/src/test/java/org/opensearch/action/search/TransportDeletePitActionTests.java
new file mode 100644
index 0000000000000..8d3cdc070c695
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/search/TransportDeletePitActionTests.java
@@ -0,0 +1,676 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.action.search;
+
+import org.opensearch.Version;
+import org.opensearch.action.support.ActionFilter;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.index.query.IdsQueryBuilder;
+import org.opensearch.index.query.MatchAllQueryBuilder;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.RemoteClusterConnectionTests;
+import org.opensearch.transport.Transport;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.action.search.PitTestsUtil.getPitId;
+import static org.opensearch.action.support.PlainActionFuture.newFuture;
+import static org.hamcrest.Matchers.containsString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Functional tests for transport delete pit action
+ */
+public class TransportDeletePitActionTests extends OpenSearchTestCase {
+    DiscoveryNode node1 = null;
+    DiscoveryNode node2 = null;
+    DiscoveryNode node3 = null;
+    String pitId = null;
+    TransportSearchAction transportSearchAction = null;
+    Task task = null;
+    DiscoveryNodes nodes = null;
+    NamedWriteableRegistry namedWriteableRegistry = null;
+    ClusterService clusterServiceMock = null;
+    Settings settings = Settings.builder().put("node.name", TransportMultiSearchActionTests.class.getSimpleName()).build();
+    private ThreadPool threadPool = new ThreadPool(settings);
+    NodeClient client = new NodeClient(settings, threadPool);
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
+    }
+
+    private MockTransportService startTransport(String id, List<DiscoveryNode> knownNodes, Version version) {
+        return startTransport(id, knownNodes, version, Settings.EMPTY);
+    }
+
+    private MockTransportService startTransport(
+        final String id,
+        final List<DiscoveryNode> knownNodes,
+        final Version version,
+        final Settings settings
+    ) {
+        return RemoteClusterConnectionTests.startTransport(id, knownNodes, version, threadPool, settings);
+    }
+
+    @Before
+    public void setupData() {
+        node1 = new DiscoveryNode("node_1", buildNewFakeTransportAddress(), Version.CURRENT);
+        node2 = new DiscoveryNode("node_2", buildNewFakeTransportAddress(), Version.CURRENT);
+        node3 = new DiscoveryNode("node_3", buildNewFakeTransportAddress(), Version.CURRENT);
+        pitId = getPitId();
+        namedWriteableRegistry = new NamedWriteableRegistry(
+            Arrays.asList(
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, TermQueryBuilder.NAME, TermQueryBuilder::new),
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, MatchAllQueryBuilder.NAME, MatchAllQueryBuilder::new),
+                new NamedWriteableRegistry.Entry(QueryBuilder.class, IdsQueryBuilder.NAME, IdsQueryBuilder::new)
+            )
+        );
+        nodes = DiscoveryNodes.builder().add(node1).add(node2).add(node3).build();
+        transportSearchAction = mock(TransportSearchAction.class);
+        task = new Task(
+            randomLong(),
+            "transport",
+            SearchAction.NAME,
+            "description",
+            new TaskId(randomLong() + ":" + randomLong()),
+            Collections.emptyMap()
+        );
+
+        clusterServiceMock = mock(ClusterService.class);
+        ClusterState state = mock(ClusterState.class);
+
+        final Settings keepAliveSettings = Settings.builder().put(CreatePitController.PIT_INIT_KEEP_ALIVE.getKey(), 30000).build();
+        when(clusterServiceMock.getSettings()).thenReturn(keepAliveSettings);
+
+        when(state.getMetadata()).thenReturn(Metadata.EMPTY_METADATA);
+        when(state.metadata()).thenReturn(Metadata.EMPTY_METADATA);
+        when(clusterServiceMock.state()).thenReturn(state);
+        when(state.getNodes()).thenReturn(nodes);
+    }
+
+    /**
+     * Test if transport call for update pit is made to all nodes present as part of PIT ID returned from phase one of create pit
+     */
+    public void testDeletePitSuccess() throws InterruptedException, ExecutionException {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        DeletePitInfo deletePitInfo = new DeletePitInfo(true, "pitId");
+                        List<DeletePitInfo> deletePitInfos = new ArrayList<>();
+                        deletePitInfos.add(deletePitInfo);
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(deletePitInfos)));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest(pitId);
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                DeletePitResponse dr = future.get();
+                assertTrue(dr.getDeletePitResults().get(0).getPitId().equals("pitId"));
+                assertTrue(dr.getDeletePitResults().get(0).isSuccessful());
+                assertEquals(3, deleteNodesInvoked.size());
+
+            }
+        }
+    }
+
+    public void testDeleteAllPITSuccess() throws InterruptedException, ExecutionException {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        final ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        DeletePitInfo deletePitInfo = new DeletePitInfo(true, "pitId");
+                        List<DeletePitInfo> deletePitInfos = new ArrayList<>();
+                        deletePitInfos.add(deletePitInfo);
+                        Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(deletePitInfos)));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client) {
+                    @Override
+                    public void getAllPits(ActionListener<GetAllPitNodesResponse> getAllPitsListener) {
+                        ListPitInfo listPitInfo = new ListPitInfo(getPitId(), 0, 0);
+                        List<ListPitInfo> list = new ArrayList<>();
+                        list.add(listPitInfo);
+                        GetAllPitNodeResponse getAllPitNodeResponse = new GetAllPitNodeResponse(
+                            cluster1Transport.getLocalDiscoNode(),
+                            list
+                        );
+                        List<GetAllPitNodeResponse> nodeList = new ArrayList();
+                        nodeList.add(getAllPitNodeResponse);
+                        getAllPitsListener.onResponse(new GetAllPitNodesResponse(new ClusterName("cn"), nodeList, new ArrayList()));
+                    }
+                };
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                DeletePitResponse dr = future.get();
+                assertTrue(dr.getDeletePitResults().get(0).getPitId().equals("pitId"));
+                assertTrue(dr.getDeletePitResults().get(0).isSuccessful());
+                assertEquals(3, deleteNodesInvoked.size());
+
+            }
+        }
+    }
+
+    public void testDeletePitWhenNodeIsDown() throws InterruptedException, ExecutionException {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+
+                        if (connection.getNode().getId() == "node_3") {
+                            Thread t = new Thread(() -> listener.onFailure(new Exception("node 3 down")));
+                            t.start();
+                        } else {
+                            Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                            t.start();
+                        }
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest(pitId);
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("node 3 down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testDeletePitWhenAllNodesAreDown() {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onFailure(new Exception("node 3 down")));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest(pitId);
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("node 3 down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testDeletePitFailure() {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextId,
+                        ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+
+                        if (connection.getNode().getId() == "node_3") {
+                            Thread t = new Thread(() -> listener.onFailure(new Exception("node down")));
+                            t.start();
+                        } else {
+                            Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                            t.start();
+                        }
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client);
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest(pitId);
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("node down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testDeleteAllPitWhenNodeIsDown() {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        final ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        if (connection.getNode().getId() == "node_3") {
+                            Thread t = new Thread(() -> listener.onFailure(new Exception("node 3 down")));
+                            t.start();
+                        } else {
+                            Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                            t.start();
+                        }
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client) {
+                    @Override
+                    public void getAllPits(ActionListener<GetAllPitNodesResponse> getAllPitsListener) {
+                        ListPitInfo listPitInfo = new ListPitInfo(getPitId(), 0, 0);
+                        List<ListPitInfo> list = new ArrayList<>();
+                        list.add(listPitInfo);
+                        GetAllPitNodeResponse getAllPitNodeResponse = new GetAllPitNodeResponse(
+                            cluster1Transport.getLocalDiscoNode(),
+                            list
+                        );
+                        List<GetAllPitNodeResponse> nodeList = new ArrayList();
+                        nodeList.add(getAllPitNodeResponse);
+                        getAllPitsListener.onResponse(new GetAllPitNodesResponse(new ClusterName("cn"), nodeList, new ArrayList()));
+                    }
+                };
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("node 3 down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testDeleteAllPitWhenAllNodesAreDown() {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+
+                    @Override
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextIds,
+                        final ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        Thread t = new Thread(() -> listener.onFailure(new Exception("node down")));
+                        t.start();
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client) {
+                    @Override
+                    public void getAllPits(ActionListener<GetAllPitNodesResponse> getAllPitsListener) {
+                        ListPitInfo listPitInfo = new ListPitInfo(getPitId(), 0, 0);
+                        List<ListPitInfo> list = new ArrayList<>();
+                        list.add(listPitInfo);
+                        GetAllPitNodeResponse getAllPitNodeResponse = new GetAllPitNodeResponse(
+                            cluster1Transport.getLocalDiscoNode(),
+                            list
+                        );
+                        List<GetAllPitNodeResponse> nodeList = new ArrayList();
+                        nodeList.add(getAllPitNodeResponse);
+                        getAllPitsListener.onResponse(new GetAllPitNodesResponse(new ClusterName("cn"), nodeList, new ArrayList()));
+                    }
+                };
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("node down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+
+    public void testDeleteAllPitFailure() {
+        List<DiscoveryNode> deleteNodesInvoked = new CopyOnWriteArrayList<>();
+        ActionFilters actionFilters = mock(ActionFilters.class);
+        when(actionFilters.filters()).thenReturn(new ActionFilter[0]);
+
+        List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
+        try (
+            MockTransportService cluster1Transport = startTransport("cluster_1_node", knownNodes, Version.CURRENT);
+            MockTransportService cluster2Transport = startTransport("cluster_2_node", knownNodes, Version.CURRENT)
+        ) {
+            knownNodes.add(cluster1Transport.getLocalDiscoNode());
+            knownNodes.add(cluster2Transport.getLocalDiscoNode());
+            Collections.shuffle(knownNodes, random());
+
+            try (
+                MockTransportService transportService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
+                transportService.start();
+                transportService.acceptIncomingRequests();
+                SearchTransportService searchTransportService = new SearchTransportService(transportService, null) {
+
+                    public void sendFreePITContexts(
+                        Transport.Connection connection,
+                        List<PitSearchContextIdForNode> contextId,
+                        final ActionListener<DeletePitResponse> listener
+                    ) {
+                        deleteNodesInvoked.add(connection.getNode());
+                        if (connection.getNode().getId() == "node_3") {
+                            Thread t = new Thread(() -> listener.onFailure(new Exception("node 3 is down")));
+                            t.start();
+                        } else {
+                            Thread t = new Thread(() -> listener.onResponse(new DeletePitResponse(new ArrayList<>())));
+                            t.start();
+                        }
+                    }
+
+                    @Override
+                    public Transport.Connection getConnection(String clusterAlias, DiscoveryNode node) {
+                        return new SearchAsyncActionTests.MockConnection(node);
+                    }
+                };
+                PitService pitService = new PitService(clusterServiceMock, searchTransportService, transportService, client) {
+                    @Override
+                    public void getAllPits(ActionListener<GetAllPitNodesResponse> getAllPitsListener) {
+                        ListPitInfo listPitInfo = new ListPitInfo(getPitId(), 0, 0);
+                        List<ListPitInfo> list = new ArrayList<>();
+                        list.add(listPitInfo);
+                        GetAllPitNodeResponse getAllPitNodeResponse = new GetAllPitNodeResponse(
+                            cluster1Transport.getLocalDiscoNode(),
+                            list
+                        );
+                        List<GetAllPitNodeResponse> nodeList = new ArrayList();
+                        nodeList.add(getAllPitNodeResponse);
+                        getAllPitsListener.onResponse(new GetAllPitNodesResponse(new ClusterName("cn"), nodeList, new ArrayList()));
+                    }
+                };
+                TransportDeletePitAction action = new TransportDeletePitAction(
+                    transportService,
+                    actionFilters,
+                    namedWriteableRegistry,
+                    pitService
+                );
+                DeletePitRequest deletePITRequest = new DeletePitRequest("_all");
+                PlainActionFuture<DeletePitResponse> future = newFuture();
+                action.execute(task, deletePITRequest, future);
+                Exception e = assertThrows(ExecutionException.class, () -> future.get());
+                assertThat(e.getMessage(), containsString("java.lang.Exception: node 3 is down"));
+                assertEquals(3, deleteNodesInvoked.size());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/search/TransportMultiSearchActionTests.java b/server/src/test/java/org/opensearch/action/search/TransportMultiSearchActionTests.java
index 09ab2438bd106..48970e2b96add 100644
--- a/server/src/test/java/org/opensearch/action/search/TransportMultiSearchActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/TransportMultiSearchActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.search;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilter;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
@@ -48,9 +47,11 @@
 import org.opensearch.common.Randomness;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
@@ -87,7 +88,8 @@ public void testParentTaskId() throws Exception {
                 TransportService.NOOP_TRANSPORT_INTERCEPTOR,
                 boundAddress -> DiscoveryNode.createLocal(settings, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
                 null,
-                Collections.emptySet()
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
             ) {
                 @Override
                 public TaskManager getTaskManager() {
@@ -151,7 +153,8 @@ public void testBatchExecute() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> DiscoveryNode.createLocal(settings, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public TaskManager getTaskManager() {
@@ -260,7 +263,7 @@ public void testDefaultMaxConcurrentSearches() {
         }
         builder.add(
             new DiscoveryNode(
-                "master",
+                "cluster_manager",
                 buildNewFakeTransportAddress(),
                 Collections.emptyMap(),
                 Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
diff --git a/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java b/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
index d1f2304365d59..c4bf8a5d87172 100644
--- a/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
@@ -33,9 +33,7 @@
 package org.opensearch.action.search;
 
 import org.apache.lucene.search.TotalHits;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.OriginalIndicesTests;
@@ -52,17 +50,19 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.InnerHitBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.TermsQueryBuilder;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.search.Scroll;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
@@ -75,6 +75,7 @@
 import org.opensearch.search.internal.InternalSearchResponse;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.sort.SortBuilders;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -234,7 +235,14 @@ public void testMergeShardsIterators() {
     }
 
     public void testProcessRemoteShards() {
-        try (TransportService transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+        try (
+            TransportService transportService = MockTransportService.createNewService(
+                Settings.EMPTY,
+                Version.CURRENT,
+                threadPool,
+                NoopTracer.INSTANCE
+            )
+        ) {
             RemoteClusterService service = transportService.getRemoteClusterService();
             assertFalse(service.isCrossClusterSearchEnabled());
             Map<String, ClusterSearchShardsResponse> searchShardsResponseMap = new HashMap<>();
@@ -451,7 +459,9 @@ public void testCCSRemoteReduceMergeFails() throws Exception {
         OriginalIndices localIndices = local ? new OriginalIndices(new String[] { "index" }, SearchRequest.DEFAULT_INDICES_OPTIONS) : null;
         TransportSearchAction.SearchTimeProvider timeProvider = new TransportSearchAction.SearchTimeProvider(0, 0, () -> 0);
         Function<Boolean, InternalAggregation.ReduceContext> reduceContext = finalReduce -> null;
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             RemoteClusterService remoteClusterService = service.getRemoteClusterService();
@@ -507,7 +517,9 @@ public void testCCSRemoteReduce() throws Exception {
         OriginalIndices localIndices = local ? new OriginalIndices(new String[] { "index" }, SearchRequest.DEFAULT_INDICES_OPTIONS) : null;
         int totalClusters = numClusters + (local ? 1 : 0);
         TransportSearchAction.SearchTimeProvider timeProvider = new TransportSearchAction.SearchTimeProvider(0, 0, () -> 0);
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             RemoteClusterService remoteClusterService = service.getRemoteClusterService();
@@ -748,7 +760,9 @@ public void testCollectSearchShards() throws Exception {
         Settings.Builder builder = Settings.builder();
         MockTransportService[] mockTransportServices = startTransport(numClusters, nodes, remoteIndicesByCluster, builder);
         Settings settings = builder.build();
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             RemoteClusterService remoteClusterService = service.getRemoteClusterService();
diff --git a/server/src/test/java/org/opensearch/action/search/TransportSearchHelperTests.java b/server/src/test/java/org/opensearch/action/search/TransportSearchHelperTests.java
index 9472518fce7ec..a9316f696ae35 100644
--- a/server/src/test/java/org/opensearch/action/search/TransportSearchHelperTests.java
+++ b/server/src/test/java/org/opensearch/action/search/TransportSearchHelperTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.util.concurrent.AtomicArray;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.SearchPhaseResult;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.search.internal.ShardSearchContextId;
diff --git a/server/src/test/java/org/opensearch/action/support/ActiveShardCountTests.java b/server/src/test/java/org/opensearch/action/support/ActiveShardCountTests.java
index a9e4b34fe5ede..89908894f2f30 100644
--- a/server/src/test/java/org/opensearch/action/support/ActiveShardCountTests.java
+++ b/server/src/test/java/org/opensearch/action/support/ActiveShardCountTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.action.support;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -43,8 +42,8 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -231,8 +230,8 @@ private ClusterState startPrimaries(final ClusterState clusterState, final Strin
         RoutingTable routingTable = clusterState.routingTable();
         IndexRoutingTable indexRoutingTable = routingTable.index(indexName);
         IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary()) {
                     shardRouting = shardRouting.initialize(randomAlphaOfLength(8), null, shardRouting.getExpectedShardSize())
@@ -249,8 +248,8 @@ private ClusterState startLessThanWaitOnShards(final ClusterState clusterState,
         RoutingTable routingTable = clusterState.routingTable();
         IndexRoutingTable indexRoutingTable = routingTable.index(indexName);
         IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             assert shardRoutingTable.getSize() > 2;
             int numToStart = numShardsToStart;
             // want less than half, and primary is already started
@@ -275,8 +274,8 @@ private ClusterState startWaitOnShards(final ClusterState clusterState, final St
         RoutingTable routingTable = clusterState.routingTable();
         IndexRoutingTable indexRoutingTable = routingTable.index(indexName);
         IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             assert shardRoutingTable.getSize() > 2;
             int numToStart = numShardsToStart;
             for (ShardRouting shardRouting : shardRoutingTable.getShards()) {
@@ -304,8 +303,8 @@ private ClusterState startAllShards(final ClusterState clusterState, final Strin
         RoutingTable routingTable = clusterState.routingTable();
         IndexRoutingTable indexRoutingTable = routingTable.index(indexName);
         IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary()) {
                     assertTrue(shardRouting.active());
diff --git a/server/src/test/java/org/opensearch/action/support/AutoCreateIndexTests.java b/server/src/test/java/org/opensearch/action/support/AutoCreateIndexTests.java
index 068414678e860..7263cbe90c1b7 100644
--- a/server/src/test/java/org/opensearch/action/support/AutoCreateIndexTests.java
+++ b/server/src/test/java/org/opensearch/action/support/AutoCreateIndexTests.java
@@ -231,7 +231,7 @@ public void testUpdate() {
             settings,
             clusterSettings,
             new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY)),
-            new SystemIndices(org.opensearch.common.collect.Map.of())
+            new SystemIndices(Map.of())
         );
         assertThat(autoCreateIndex.getAutoCreate().isAutoCreateIndex(), equalTo(value));
 
@@ -257,12 +257,7 @@ private static ClusterState buildClusterState(String... indices) {
     }
 
     private AutoCreateIndex newAutoCreateIndex(Settings settings) {
-        SystemIndices systemIndices = new SystemIndices(
-            org.opensearch.common.collect.Map.of(
-                "plugin",
-                org.opensearch.common.collect.List.of(new SystemIndexDescriptor(TEST_SYSTEM_INDEX_NAME, ""))
-            )
-        );
+        SystemIndices systemIndices = new SystemIndices(Map.of("plugin", List.of(new SystemIndexDescriptor(TEST_SYSTEM_INDEX_NAME, ""))));
         return new AutoCreateIndex(
             settings,
             new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
diff --git a/server/src/test/java/org/opensearch/action/support/ContextPreservingActionListenerTests.java b/server/src/test/java/org/opensearch/action/support/ContextPreservingActionListenerTests.java
index 6ca38b2a2fc4f..0b9f2c6707c02 100644
--- a/server/src/test/java/org/opensearch/action/support/ContextPreservingActionListenerTests.java
+++ b/server/src/test/java/org/opensearch/action/support/ContextPreservingActionListenerTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/support/GroupedActionListenerTests.java b/server/src/test/java/org/opensearch/action/support/GroupedActionListenerTests.java
index bbdd2351910d6..bac019264b7d3 100644
--- a/server/src/test/java/org/opensearch/action/support/GroupedActionListenerTests.java
+++ b/server/src/test/java/org/opensearch/action/support/GroupedActionListenerTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/support/IndicesOptionsTests.java b/server/src/test/java/org/opensearch/action/support/IndicesOptionsTests.java
index 21ce9c29c6a03..fb59d0b21e2cb 100644
--- a/server/src/test/java/org/opensearch/action/support/IndicesOptionsTests.java
+++ b/server/src/test/java/org/opensearch/action/support/IndicesOptionsTests.java
@@ -36,17 +36,17 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.IndicesOptions.Option;
 import org.opensearch.action.support.IndicesOptions.WildcardStates;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent.MapParams;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent.MapParams;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -430,7 +430,7 @@ public void testFromXContentWithWildcardSpecialValues() throws IOException {
         final boolean allowNoIndices = randomBoolean();
 
         BytesReference xContentBytes;
-        try (XContentBuilder builder = XContentFactory.contentBuilder(type)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(type)) {
             builder.startObject();
             builder.field("expand_wildcards", "all");
             builder.field("ignore_unavailable", ignoreUnavailable);
@@ -449,7 +449,7 @@ public void testFromXContentWithWildcardSpecialValues() throws IOException {
         assertTrue(fromXContentOptions.expandWildcardsHidden());
         assertTrue(fromXContentOptions.expandWildcardsOpen());
 
-        try (XContentBuilder builder = XContentFactory.contentBuilder(type)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(type)) {
             builder.startObject();
             builder.field("expand_wildcards", "none");
             builder.field("ignore_unavailable", ignoreUnavailable);
@@ -469,7 +469,7 @@ public void testFromXContentWithWildcardSpecialValues() throws IOException {
     }
 
     private BytesReference toXContentBytes(IndicesOptions indicesOptions, XContentType type) throws IOException {
-        try (XContentBuilder builder = XContentFactory.contentBuilder(type)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(type)) {
             builder.startObject();
             indicesOptions.toXContent(builder, new MapParams(Collections.emptyMap()));
             builder.endObject();
diff --git a/server/src/test/java/org/opensearch/action/support/ListenableActionFutureTests.java b/server/src/test/java/org/opensearch/action/support/ListenableActionFutureTests.java
index b3fa03a3f873c..c69d357e51fc9 100644
--- a/server/src/test/java/org/opensearch/action/support/ListenableActionFutureTests.java
+++ b/server/src/test/java/org/opensearch/action/support/ListenableActionFutureTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/action/support/ListenerTimeoutsTests.java b/server/src/test/java/org/opensearch/action/support/ListenerTimeoutsTests.java
index 9e9f27688e121..424a7c1d16895 100644
--- a/server/src/test/java/org/opensearch/action/support/ListenerTimeoutsTests.java
+++ b/server/src/test/java/org/opensearch/action/support/ListenerTimeoutsTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.action.support;
 
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.Before;
diff --git a/server/src/test/java/org/opensearch/action/support/RefreshPolicyTests.java b/server/src/test/java/org/opensearch/action/support/RefreshPolicyTests.java
index c8e1225b09cb8..32e909a8b8338 100644
--- a/server/src/test/java/org/opensearch/action/support/RefreshPolicyTests.java
+++ b/server/src/test/java/org/opensearch/action/support/RefreshPolicyTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.action.support;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/support/RetryableActionTests.java b/server/src/test/java/org/opensearch/action/support/RetryableActionTests.java
index fc6853ecdc9af..fe2994f9fe9bb 100644
--- a/server/src/test/java/org/opensearch/action/support/RetryableActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/RetryableActionTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.action.support;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/action/support/TransportActionFilterChainTests.java b/server/src/test/java/org/opensearch/action/support/TransportActionFilterChainTests.java
index fbc7976822501..a4f40db365f9a 100644
--- a/server/src/test/java/org/opensearch/action/support/TransportActionFilterChainTests.java
+++ b/server/src/test/java/org/opensearch/action/support/TransportActionFilterChainTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.action.support;
 
 import org.opensearch.OpenSearchTimeoutException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.LatchedActionListener;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.node.Node;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskManager;
diff --git a/server/src/test/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeActionTests.java b/server/src/test/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeActionTests.java
index 2830a42dfae76..4305151965ab6 100644
--- a/server/src/test/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeActionTests.java
@@ -36,7 +36,6 @@
 import org.opensearch.Version;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
@@ -60,20 +59,22 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ReceiveTimeoutTransportException;
 import org.opensearch.transport.TestTransportChannel;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 import org.junit.After;
 import org.junit.AfterClass;
@@ -237,7 +238,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -284,7 +286,7 @@ void setClusterState(ClusterService clusterService, String index) {
             }
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(numberOfNodes - 1).getId());
+        discoBuilder.clusterManagerNodeId(newNode(numberOfNodes - 1).getId());
         ClusterState.Builder stateBuilder = ClusterState.builder(new ClusterName(TEST_CLUSTER));
         stateBuilder.nodes(discoBuilder);
         final IndexMetadata.Builder indexMetadata = IndexMetadata.builder(index)
@@ -366,17 +368,17 @@ public void testOneRequestIsSentToEachNodeHoldingAShard() {
         }
     }
 
-    // simulate the master being removed from the cluster but before a new master is elected
-    // as such, the shards assigned to the master will still show up in the cluster state as assigned to a node but
-    // that node will not be in the local cluster state on any node that has detected the master as failing
+    // simulate the cluster-manager being removed from the cluster but before a new cluster-manager is elected
+    // as such, the shards assigned to the cluster-manager will still show up in the cluster state as assigned to a node but
+    // that node will not be in the local cluster state on any node that has detected the cluster-manager as failing
     // in this case, such a shard should be treated as unassigned
-    public void testRequestsAreNotSentToFailedMaster() {
+    public void testRequestsAreNotSentToFailedClusterManager() {
         Request request = new Request(new String[] { TEST_INDEX });
         PlainActionFuture<Response> listener = new PlainActionFuture<>();
 
-        DiscoveryNode masterNode = clusterService.state().nodes().getMasterNode();
+        DiscoveryNode clusterManagerNode = clusterService.state().nodes().getClusterManagerNode();
         DiscoveryNodes.Builder builder = DiscoveryNodes.builder(clusterService.state().getNodes());
-        builder.remove(masterNode.getId());
+        builder.remove(clusterManagerNode.getId());
 
         setState(clusterService, ClusterState.builder(clusterService.state()).nodes(builder));
 
@@ -384,11 +386,11 @@ public void testRequestsAreNotSentToFailedMaster() {
 
         Map<String, List<CapturingTransport.CapturedRequest>> capturedRequests = transport.getCapturedRequestsByTargetNodeAndClear();
 
-        // the master should not be in the list of nodes that requests were sent to
+        // the cluster manager should not be in the list of nodes that requests were sent to
         ShardsIterator shardIt = clusterService.state().routingTable().allShards(new String[] { TEST_INDEX });
         Set<String> set = new HashSet<>();
         for (ShardRouting shard : shardIt) {
-            if (!shard.currentNodeId().equals(masterNode.getId())) {
+            if (!shard.currentNodeId().equals(clusterManagerNode.getId())) {
                 set.add(shard.currentNodeId());
             }
         }
@@ -399,7 +401,7 @@ public void testRequestsAreNotSentToFailedMaster() {
         // check requests were sent to the right nodes
         assertEquals(set, capturedRequests.keySet());
         for (Map.Entry<String, List<CapturingTransport.CapturedRequest>> entry : capturedRequests.entrySet()) {
-            // check one request was sent to each non-master node
+            // check one request was sent to each non-cluster-manager node
             assertEquals(1, entry.getValue().size());
         }
     }
@@ -456,14 +458,14 @@ public void testResultAggregation() throws ExecutionException, InterruptedExcept
         Request request = new Request(new String[] { TEST_INDEX });
         PlainActionFuture<Response> listener = new PlainActionFuture<>();
 
-        // simulate removing the master
-        final boolean simulateFailedMasterNode = rarely();
-        DiscoveryNode failedMasterNode = null;
-        if (simulateFailedMasterNode) {
-            failedMasterNode = clusterService.state().nodes().getMasterNode();
+        // simulate removing the cluster-manager
+        final boolean simulateFailedClusterManagerNode = rarely();
+        DiscoveryNode failedClusterManagerNode = null;
+        if (simulateFailedClusterManagerNode) {
+            failedClusterManagerNode = clusterService.state().nodes().getClusterManagerNode();
             DiscoveryNodes.Builder builder = DiscoveryNodes.builder(clusterService.state().getNodes());
-            builder.remove(failedMasterNode.getId());
-            builder.masterNodeId(null);
+            builder.remove(failedClusterManagerNode.getId());
+            builder.clusterManagerNodeId(null);
 
             setState(clusterService, ClusterState.builder(clusterService.state()).nodes(builder));
         }
@@ -511,8 +513,8 @@ public void testResultAggregation() throws ExecutionException, InterruptedExcept
                 transport.handleResponse(requestId, nodeResponse);
             }
         }
-        if (simulateFailedMasterNode) {
-            totalShards += map.get(failedMasterNode.getId()).size();
+        if (simulateFailedClusterManagerNode) {
+            totalShards += map.get(failedClusterManagerNode.getId()).size();
         }
 
         Response response = listener.get();
diff --git a/server/src/test/java/org/opensearch/action/support/master/ShardsAcknowledgedResponseTests.java b/server/src/test/java/org/opensearch/action/support/clustermanager/ShardsAcknowledgedResponseTests.java
similarity index 88%
rename from server/src/test/java/org/opensearch/action/support/master/ShardsAcknowledgedResponseTests.java
rename to server/src/test/java/org/opensearch/action/support/clustermanager/ShardsAcknowledgedResponseTests.java
index 90a428a765053..68b7d97fa1427 100644
--- a/server/src/test/java/org/opensearch/action/support/master/ShardsAcknowledgedResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/support/clustermanager/ShardsAcknowledgedResponseTests.java
@@ -29,12 +29,13 @@
  * GitHub history for details.
  */
 
-package org.opensearch.action.support.master;
+package org.opensearch.action.support.clustermanager;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.action.support.master.ShardsAcknowledgedResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeActionTests.java b/server/src/test/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeActionTests.java
new file mode 100644
index 0000000000000..9ae1310a8b15c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeActionTests.java
@@ -0,0 +1,713 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.ThreadedActionListener;
+import org.opensearch.action.support.replication.ClusterStateCreationUtils;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.NotClusterManagerException;
+import org.opensearch.cluster.block.ClusterBlock;
+import org.opensearch.cluster.block.ClusterBlockException;
+import org.opensearch.cluster.block.ClusterBlockLevel;
+import org.opensearch.cluster.block.ClusterBlocks;
+import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterManagerThrottlingException;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.discovery.ClusterManagerNotDiscoveredException;
+import org.opensearch.node.NodeClosedException;
+import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.transport.TransportService;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+import static org.opensearch.test.ClusterServiceUtils.setState;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+
+public class TransportClusterManagerNodeActionTests extends OpenSearchTestCase {
+    private static ThreadPool threadPool;
+
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private CapturingTransport transport;
+    private DiscoveryNode localNode;
+    private DiscoveryNode remoteNode;
+    private DiscoveryNode[] allNodes;
+
+    @BeforeClass
+    public static void beforeClass() {
+        threadPool = new TestThreadPool("TransportMasterNodeActionTests");
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        transport = new CapturingTransport();
+        clusterService = createClusterService(threadPool);
+        transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            x -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        localNode = new DiscoveryNode(
+            "local_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+        remoteNode = new DiscoveryNode(
+            "remote_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+        allNodes = new DiscoveryNode[] { localNode, remoteNode };
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        clusterService.close();
+        transportService.close();
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+        threadPool = null;
+    }
+
+    void assertListenerThrows(String msg, ActionFuture<?> listener, Class<?> klass) throws InterruptedException {
+        try {
+            listener.get();
+            fail(msg);
+        } catch (ExecutionException ex) {
+            assertThat(ex.getCause(), instanceOf(klass));
+        }
+    }
+
+    public static class Request extends ClusterManagerNodeRequest<Request> {
+        Request() {}
+
+        Request(StreamInput in) throws IOException {
+            super(in);
+        }
+
+        @Override
+        public ActionRequestValidationException validate() {
+            return null;
+        }
+    }
+
+    class Response extends ActionResponse {
+        private long identity = randomLong();
+
+        Response() {}
+
+        Response(StreamInput in) throws IOException {
+            super(in);
+            identity = in.readLong();
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Response response = (Response) o;
+            return identity == response.identity;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(identity);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeLong(identity);
+        }
+    }
+
+    class Action extends TransportClusterManagerNodeAction<Request, Response> {
+        Action(String actionName, TransportService transportService, ClusterService clusterService, ThreadPool threadPool) {
+            super(
+                actionName,
+                transportService,
+                clusterService,
+                threadPool,
+                new ActionFilters(new HashSet<>()),
+                Request::new,
+                new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY))
+            );
+        }
+
+        @Override
+        protected void doExecute(Task task, final Request request, ActionListener<Response> listener) {
+            // remove unneeded threading by wrapping listener with SAME to prevent super.doExecute from wrapping it with LISTENER
+            super.doExecute(task, request, new ThreadedActionListener<>(logger, threadPool, ThreadPool.Names.SAME, listener, false));
+        }
+
+        @Override
+        protected String executor() {
+            // very lightweight operation in memory, no need to fork to a thread
+            return ThreadPool.Names.SAME;
+        }
+
+        @Override
+        protected Response read(StreamInput in) throws IOException {
+            return new Response(in);
+        }
+
+        @Override
+        protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
+            listener.onResponse(new Response()); // default implementation, overridden in specific tests
+        }
+
+        @Override
+        protected ClusterBlockException checkBlock(Request request, ClusterState state) {
+            return null; // default implementation, overridden in specific tests
+        }
+    }
+
+    public void testLocalOperationWithoutBlocks() throws ExecutionException, InterruptedException {
+        final boolean clusterManagerOperationFailure = randomBoolean();
+
+        Request request = new Request();
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        final Exception exception = new Exception();
+        final Response response = new Response();
+
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected void clusterManagerOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) {
+                if (clusterManagerOperationFailure) {
+                    listener.onFailure(exception);
+                } else {
+                    listener.onResponse(response);
+                }
+            }
+        }.execute(request, listener);
+        assertTrue(listener.isDone());
+
+        if (clusterManagerOperationFailure) {
+            try {
+                listener.get();
+                fail("Expected exception but returned proper result");
+            } catch (ExecutionException ex) {
+                assertThat(ex.getCause(), equalTo(exception));
+            }
+        } else {
+            assertThat(listener.get(), equalTo(response));
+        }
+    }
+
+    /* The test is copied from testLocalOperationWithoutBlocks()
+    to validate the backwards compatibility for the deprecated method masterOperation(with task parameter). */
+    public void testDeprecatedMasterOperationWithTaskParameterCanBeCalled() throws ExecutionException, InterruptedException {
+        final boolean clusterManagerOperationFailure = randomBoolean();
+
+        Request request = new Request();
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        final Exception exception = new Exception();
+        final Response response = new Response();
+
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) {
+                if (clusterManagerOperationFailure) {
+                    listener.onFailure(exception);
+                } else {
+                    listener.onResponse(response);
+                }
+            }
+        }.execute(request, listener);
+        assertTrue(listener.isDone());
+
+        if (clusterManagerOperationFailure) {
+            try {
+                listener.get();
+                fail("Expected exception but returned proper result");
+            } catch (ExecutionException ex) {
+                assertThat(ex.getCause(), equalTo(exception));
+            }
+        } else {
+            assertThat(listener.get(), equalTo(response));
+        }
+    }
+
+    public void testLocalOperationWithBlocks() throws ExecutionException, InterruptedException {
+        final boolean retryableBlock = randomBoolean();
+        final boolean unblockBeforeTimeout = randomBoolean();
+
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueSeconds(unblockBeforeTimeout ? 60 : 0));
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        ClusterBlock block = new ClusterBlock(1, "", retryableBlock, true, false, randomFrom(RestStatus.values()), ClusterBlockLevel.ALL);
+        ClusterState stateWithBlock = ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
+            .blocks(ClusterBlocks.builder().addGlobalBlock(block))
+            .build();
+        setState(clusterService, stateWithBlock);
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected ClusterBlockException checkBlock(Request request, ClusterState state) {
+                Set<ClusterBlock> blocks = state.blocks().global();
+                return blocks.isEmpty() ? null : new ClusterBlockException(blocks);
+            }
+        }.execute(request, listener);
+
+        if (retryableBlock && unblockBeforeTimeout) {
+            assertFalse(listener.isDone());
+            setState(
+                clusterService,
+                ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
+                    .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
+                    .build()
+            );
+            assertTrue(listener.isDone());
+            listener.get();
+            return;
+        }
+
+        assertTrue(listener.isDone());
+        if (retryableBlock) {
+            try {
+                listener.get();
+                fail("Expected exception but returned proper result");
+            } catch (ExecutionException ex) {
+                assertThat(ex.getCause(), instanceOf(ClusterManagerNotDiscoveredException.class));
+                assertThat(ex.getCause().getCause(), instanceOf(ClusterBlockException.class));
+            }
+        } else {
+            assertListenerThrows("ClusterBlockException should be thrown", listener, ClusterBlockException.class);
+        }
+    }
+
+    public void testCheckBlockThrowsException() throws InterruptedException {
+        boolean throwExceptionOnRetry = randomBoolean();
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueSeconds(60));
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        ClusterBlock block = new ClusterBlock(1, "", true, true, false, randomFrom(RestStatus.values()), ClusterBlockLevel.ALL);
+        ClusterState stateWithBlock = ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
+            .blocks(ClusterBlocks.builder().addGlobalBlock(block))
+            .build();
+        setState(clusterService, stateWithBlock);
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected ClusterBlockException checkBlock(Request request, ClusterState state) {
+                Set<ClusterBlock> blocks = state.blocks().global();
+                if (throwExceptionOnRetry == false || blocks.isEmpty()) {
+                    throw new RuntimeException("checkBlock has thrown exception");
+                }
+                return new ClusterBlockException(blocks);
+
+            }
+        }.execute(request, listener);
+
+        if (throwExceptionOnRetry == false) {
+            assertListenerThrows("checkBlock has thrown exception", listener, RuntimeException.class);
+        } else {
+            assertFalse(listener.isDone());
+            setState(
+                clusterService,
+                ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
+                    .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
+                    .build()
+            );
+            assertListenerThrows("checkBlock has thrown exception", listener, RuntimeException.class);
+        }
+    }
+
+    public void testForceLocalOperation() throws ExecutionException, InterruptedException {
+        Request request = new Request();
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, randomFrom(localNode, remoteNode, null), allNodes));
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected boolean localExecute(Request request) {
+                return true;
+            }
+        }.execute(request, listener);
+
+        assertTrue(listener.isDone());
+        listener.get();
+    }
+
+    public void testClusterManagerNotAvailable() throws ExecutionException, InterruptedException {
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueSeconds(0));
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, null, allNodes));
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
+        assertTrue(listener.isDone());
+        assertListenerThrows("ClusterManagerNotDiscoveredException should be thrown", listener, ClusterManagerNotDiscoveredException.class);
+    }
+
+    public void testClusterManagerBecomesAvailable() throws ExecutionException, InterruptedException {
+        Request request = new Request();
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, null, allNodes));
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
+        assertFalse(listener.isDone());
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
+        assertTrue(listener.isDone());
+        listener.get();
+    }
+
+    public void testDelegateToClusterManager() throws ExecutionException, InterruptedException {
+        Request request = new Request();
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, remoteNode, allNodes));
+
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
+
+        assertThat(transport.capturedRequests().length, equalTo(1));
+        CapturingTransport.CapturedRequest capturedRequest = transport.capturedRequests()[0];
+        assertTrue(capturedRequest.node.isClusterManagerNode());
+        assertThat(capturedRequest.request, equalTo(request));
+        assertThat(capturedRequest.action, equalTo("internal:testAction"));
+
+        Response response = new Response();
+        transport.handleResponse(capturedRequest.requestId, response);
+        assertTrue(listener.isDone());
+        assertThat(listener.get(), equalTo(response));
+    }
+
+    public void testDelegateToFailingClusterManager() throws ExecutionException, InterruptedException {
+        boolean failsWithConnectTransportException = randomBoolean();
+        boolean rejoinSameClusterManager = failsWithConnectTransportException && randomBoolean();
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueSeconds(failsWithConnectTransportException ? 60 : 0));
+        DiscoveryNode clusterManagerNode = this.remoteNode;
+        setState(
+            clusterService,
+            // use a random base version so it can go down when simulating a restart.
+            ClusterState.builder(ClusterStateCreationUtils.state(localNode, clusterManagerNode, allNodes)).version(randomIntBetween(0, 10))
+        );
+
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
+
+        CapturingTransport.CapturedRequest[] capturedRequests = transport.getCapturedRequestsAndClear();
+        assertThat(capturedRequests.length, equalTo(1));
+        CapturingTransport.CapturedRequest capturedRequest = capturedRequests[0];
+        assertTrue(capturedRequest.node.isClusterManagerNode());
+        assertThat(capturedRequest.request, equalTo(request));
+        assertThat(capturedRequest.action, equalTo("internal:testAction"));
+
+        if (rejoinSameClusterManager) {
+            transport.handleRemoteError(
+                capturedRequest.requestId,
+                randomBoolean()
+                    ? new ConnectTransportException(clusterManagerNode, "Fake error")
+                    : new NodeClosedException(clusterManagerNode)
+            );
+            assertFalse(listener.isDone());
+            if (randomBoolean()) {
+                // simulate cluster-manager node removal
+                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
+                nodesBuilder.clusterManagerNodeId(null);
+                setState(clusterService, ClusterState.builder(clusterService.state()).nodes(nodesBuilder));
+            }
+            if (randomBoolean()) {
+                // reset the same state to increment a version simulating a join of an existing node
+                // simulating use being disconnected
+                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
+                nodesBuilder.clusterManagerNodeId(clusterManagerNode.getId());
+                setState(clusterService, ClusterState.builder(clusterService.state()).nodes(nodesBuilder));
+            } else {
+                // simulate cluster-manager restart followed by a state recovery - this will reset the cluster state version
+                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
+                nodesBuilder.remove(clusterManagerNode);
+                clusterManagerNode = new DiscoveryNode(
+                    clusterManagerNode.getId(),
+                    clusterManagerNode.getAddress(),
+                    clusterManagerNode.getVersion()
+                );
+                nodesBuilder.add(clusterManagerNode);
+                nodesBuilder.clusterManagerNodeId(clusterManagerNode.getId());
+                final ClusterState.Builder builder = ClusterState.builder(clusterService.state()).nodes(nodesBuilder);
+                setState(clusterService, builder.version(0));
+            }
+            assertFalse(listener.isDone());
+            capturedRequests = transport.getCapturedRequestsAndClear();
+            assertThat(capturedRequests.length, equalTo(1));
+            capturedRequest = capturedRequests[0];
+            assertTrue(capturedRequest.node.isClusterManagerNode());
+            assertThat(capturedRequest.request, equalTo(request));
+            assertThat(capturedRequest.action, equalTo("internal:testAction"));
+        } else if (failsWithConnectTransportException) {
+            transport.handleRemoteError(capturedRequest.requestId, new ConnectTransportException(clusterManagerNode, "Fake error"));
+            assertFalse(listener.isDone());
+            setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
+            assertTrue(listener.isDone());
+            listener.get();
+        } else {
+            OpenSearchException t = new OpenSearchException("test");
+            t.addHeader("header", "is here");
+            transport.handleRemoteError(capturedRequest.requestId, t);
+            assertTrue(listener.isDone());
+            try {
+                listener.get();
+                fail("Expected exception but returned proper result");
+            } catch (ExecutionException ex) {
+                final Throwable cause = ex.getCause().getCause();
+                assertThat(cause, instanceOf(OpenSearchException.class));
+                final OpenSearchException es = (OpenSearchException) cause;
+                assertThat(es.getMessage(), equalTo(t.getMessage()));
+                assertThat(es.getHeader("header"), equalTo(t.getHeader("header")));
+            }
+        }
+    }
+
+    public void testClusterManagerFailoverAfterStepDown() throws ExecutionException, InterruptedException {
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueHours(1));
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+
+        final Response response = new Response();
+
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
+
+        new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected void clusterManagerOperation(Request request, ClusterState state, ActionListener<Response> listener)
+                throws Exception {
+                // The other node has become cluster-manager, simulate failures of this node while publishing cluster state through
+                // ZenDiscovery
+                setState(clusterService, ClusterStateCreationUtils.state(localNode, remoteNode, allNodes));
+                Exception failure = randomBoolean()
+                    ? new FailedToCommitClusterStateException("Fake error")
+                    : new NotClusterManagerException("Fake error");
+                listener.onFailure(failure);
+            }
+        }.execute(request, listener);
+
+        assertThat(transport.capturedRequests().length, equalTo(1));
+        CapturingTransport.CapturedRequest capturedRequest = transport.capturedRequests()[0];
+        assertTrue(capturedRequest.node.isClusterManagerNode());
+        assertThat(capturedRequest.request, equalTo(request));
+        assertThat(capturedRequest.action, equalTo("internal:testAction"));
+
+        transport.handleResponse(capturedRequest.requestId, response);
+        assertTrue(listener.isDone());
+        assertThat(listener.get(), equalTo(response));
+    }
+
+    // Validate TransportMasterNodeAction.testDelegateToClusterManager() works correctly on node with the deprecated MASTER_ROLE.
+    public void testDelegateToClusterManagerOnNodeWithDeprecatedMasterRole() throws ExecutionException, InterruptedException {
+        DiscoveryNode localNode = new DiscoveryNode(
+            "local_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+        DiscoveryNode remoteNode = new DiscoveryNode(
+            "remote_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+        DiscoveryNode[] allNodes = new DiscoveryNode[] { localNode, remoteNode };
+
+        Request request = new Request();
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, remoteNode, allNodes));
+
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
+
+        assertThat(transport.capturedRequests().length, equalTo(1));
+        CapturingTransport.CapturedRequest capturedRequest = transport.capturedRequests()[0];
+        assertTrue(capturedRequest.node.isClusterManagerNode());
+        assertThat(capturedRequest.request, equalTo(request));
+        assertThat(capturedRequest.action, equalTo("internal:testAction"));
+
+        Response response = new Response();
+        transport.handleResponse(capturedRequest.requestId, response);
+        assertTrue(listener.isDone());
+        assertThat(listener.get(), equalTo(response));
+    }
+
+    public void testThrottlingRetryLocalMaster() throws InterruptedException, BrokenBarrierException {
+        Request request = new Request();
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        AtomicBoolean exception = new AtomicBoolean(true);
+        AtomicBoolean retried = new AtomicBoolean(false);
+        CyclicBarrier barrier = new CyclicBarrier(2);
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, new DiscoveryNode[] { localNode }));
+
+        TransportClusterManagerNodeAction action = new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) {
+                if (exception.getAndSet(false)) {
+                    throw new ClusterManagerThrottlingException("Throttling Exception : Limit exceeded for test");
+                } else {
+                    try {
+                        retried.set(true);
+                        barrier.await();
+                    } catch (Exception e) {
+                        throw new AssertionError();
+                    }
+                }
+            }
+        };
+        action.execute(request, listener);
+
+        barrier.await();
+        assertTrue(retried.get());
+        assertFalse(exception.get());
+    }
+
+    public void testThrottlingRetryRemoteMaster() throws ExecutionException, InterruptedException {
+        Request request = new Request().clusterManagerNodeTimeout(TimeValue.timeValueSeconds(60));
+        DiscoveryNode masterNode = this.remoteNode;
+        setState(
+            clusterService,
+            // use a random base version so it can go down when simulating a restart.
+            ClusterState.builder(ClusterStateCreationUtils.state(localNode, masterNode, new DiscoveryNode[] { localNode, masterNode }))
+                .version(randomIntBetween(0, 10))
+        );
+
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        TransportClusterManagerNodeAction action = new Action("internal:testAction", transportService, clusterService, threadPool);
+        action.execute(request, listener);
+
+        CapturingTransport.CapturedRequest[] capturedRequests = transport.getCapturedRequestsAndClear();
+        assertThat(capturedRequests.length, equalTo(1));
+        CapturingTransport.CapturedRequest capturedRequest = capturedRequests[0];
+        assertTrue(capturedRequest.node.isMasterNode());
+        assertThat(capturedRequest.request, equalTo(request));
+        assertThat(capturedRequest.action, equalTo("internal:testAction"));
+        transport.handleRemoteError(
+            capturedRequest.requestId,
+            new ClusterManagerThrottlingException("Throttling Exception : Limit exceeded for test")
+        );
+
+        assertFalse(listener.isDone());
+
+        // waiting for retry to trigger
+        Thread.sleep(10000);
+
+        // Retry for above throttling exception
+        capturedRequests = transport.getCapturedRequestsAndClear();
+        assertThat(capturedRequests.length, equalTo(1));
+        capturedRequest = capturedRequests[0];
+        Response response = new Response();
+        transport.handleResponse(capturedRequest.requestId, response);
+
+        assertTrue(listener.isDone());
+        listener.get();
+    }
+
+    public void testRetryForDifferentException() throws InterruptedException, BrokenBarrierException {
+        Request request = new Request();
+        PlainActionFuture<Response> listener = new PlainActionFuture<>();
+        AtomicBoolean exception = new AtomicBoolean(true);
+        AtomicBoolean retried = new AtomicBoolean(false);
+        CyclicBarrier barrier = new CyclicBarrier(2);
+        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, new DiscoveryNode[] { localNode }));
+
+        TransportClusterManagerNodeAction action = new Action("internal:testAction", transportService, clusterService, threadPool) {
+            @Override
+            protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener)
+                throws Exception {
+                if (exception.getAndSet(false)) {
+                    throw new Exception("Different exception");
+                } else {
+                    // If called second time due to retry, throw exception
+                    retried.set(true);
+                    throw new AssertionError("Should not retry for other exception");
+                }
+            }
+        };
+        action.execute(request, listener);
+
+        assertFalse(retried.get());
+        assertFalse(exception.get());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/support/clustermanager/TransportMasterNodeActionUtils.java b/server/src/test/java/org/opensearch/action/support/clustermanager/TransportMasterNodeActionUtils.java
new file mode 100644
index 0000000000000..ce44c4d2c5b48
--- /dev/null
+++ b/server/src/test/java/org/opensearch/action/support/clustermanager/TransportMasterNodeActionUtils.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.action.support.clustermanager;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+
+public class TransportMasterNodeActionUtils {
+
+    /**
+     * Allows to directly call {@link TransportClusterManagerNodeAction#clusterManagerOperation(ClusterManagerNodeRequest, ClusterState, ActionListener)} which is
+     * a protected method.
+     */
+    public static <Request extends ClusterManagerNodeRequest<Request>, Response extends ActionResponse> void runClusterManagerOperation(
+        TransportClusterManagerNodeAction<Request, Response> clusterManagerNodeAction,
+        Request request,
+        ClusterState clusterState,
+        ActionListener<Response> actionListener
+    ) throws Exception {
+        assert clusterManagerNodeAction.checkBlock(request, clusterState) == null;
+        clusterManagerNodeAction.clusterManagerOperation(request, clusterState, actionListener);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionTests.java b/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionTests.java
deleted file mode 100644
index a8ad356e947b5..0000000000000
--- a/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionTests.java
+++ /dev/null
@@ -1,528 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.support.master;
-
-import org.opensearch.OpenSearchException;
-import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.action.support.ThreadedActionListener;
-import org.opensearch.action.support.replication.ClusterStateCreationUtils;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.NotMasterException;
-import org.opensearch.cluster.block.ClusterBlock;
-import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.block.ClusterBlockLevel;
-import org.opensearch.cluster.block.ClusterBlocks;
-import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
-import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.discovery.MasterNotDiscoveredException;
-import org.opensearch.node.NodeClosedException;
-import org.opensearch.rest.RestStatus;
-import org.opensearch.tasks.Task;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.test.transport.CapturingTransport;
-import org.opensearch.threadpool.TestThreadPool;
-import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.ConnectTransportException;
-import org.opensearch.transport.TransportService;
-import org.junit.After;
-import org.junit.AfterClass;
-import org.junit.Before;
-import org.junit.BeforeClass;
-
-import java.io.IOException;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.Objects;
-import java.util.Set;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.TimeUnit;
-
-import static org.opensearch.test.ClusterServiceUtils.createClusterService;
-import static org.opensearch.test.ClusterServiceUtils.setState;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.instanceOf;
-
-public class TransportMasterNodeActionTests extends OpenSearchTestCase {
-    private static ThreadPool threadPool;
-
-    private ClusterService clusterService;
-    private TransportService transportService;
-    private CapturingTransport transport;
-    private DiscoveryNode localNode;
-    private DiscoveryNode remoteNode;
-    private DiscoveryNode[] allNodes;
-
-    @BeforeClass
-    public static void beforeClass() {
-        threadPool = new TestThreadPool("TransportMasterNodeActionTests");
-    }
-
-    @Override
-    @Before
-    public void setUp() throws Exception {
-        super.setUp();
-        transport = new CapturingTransport();
-        clusterService = createClusterService(threadPool);
-        transportService = transport.createTransportService(
-            clusterService.getSettings(),
-            threadPool,
-            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
-            x -> clusterService.localNode(),
-            null,
-            Collections.emptySet()
-        );
-        transportService.start();
-        transportService.acceptIncomingRequests();
-        localNode = new DiscoveryNode(
-            "local_node",
-            buildNewFakeTransportAddress(),
-            Collections.emptyMap(),
-            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
-            Version.CURRENT
-        );
-        remoteNode = new DiscoveryNode(
-            "remote_node",
-            buildNewFakeTransportAddress(),
-            Collections.emptyMap(),
-            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
-            Version.CURRENT
-        );
-        allNodes = new DiscoveryNode[] { localNode, remoteNode };
-    }
-
-    @After
-    public void tearDown() throws Exception {
-        super.tearDown();
-        clusterService.close();
-        transportService.close();
-    }
-
-    @AfterClass
-    public static void afterClass() {
-        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
-        threadPool = null;
-    }
-
-    void assertListenerThrows(String msg, ActionFuture<?> listener, Class<?> klass) throws InterruptedException {
-        try {
-            listener.get();
-            fail(msg);
-        } catch (ExecutionException ex) {
-            assertThat(ex.getCause(), instanceOf(klass));
-        }
-    }
-
-    public static class Request extends MasterNodeRequest<Request> {
-        Request() {}
-
-        Request(StreamInput in) throws IOException {
-            super(in);
-        }
-
-        @Override
-        public ActionRequestValidationException validate() {
-            return null;
-        }
-    }
-
-    class Response extends ActionResponse {
-        private long identity = randomLong();
-
-        Response() {}
-
-        Response(StreamInput in) throws IOException {
-            super(in);
-            identity = in.readLong();
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (this == o) return true;
-            if (o == null || getClass() != o.getClass()) return false;
-            Response response = (Response) o;
-            return identity == response.identity;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(identity);
-        }
-
-        @Override
-        public void writeTo(StreamOutput out) throws IOException {
-            out.writeLong(identity);
-        }
-    }
-
-    class Action extends TransportMasterNodeAction<Request, Response> {
-        Action(String actionName, TransportService transportService, ClusterService clusterService, ThreadPool threadPool) {
-            super(
-                actionName,
-                transportService,
-                clusterService,
-                threadPool,
-                new ActionFilters(new HashSet<>()),
-                Request::new,
-                new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY))
-            );
-        }
-
-        @Override
-        protected void doExecute(Task task, final Request request, ActionListener<Response> listener) {
-            // remove unneeded threading by wrapping listener with SAME to prevent super.doExecute from wrapping it with LISTENER
-            super.doExecute(task, request, new ThreadedActionListener<>(logger, threadPool, ThreadPool.Names.SAME, listener, false));
-        }
-
-        @Override
-        protected String executor() {
-            // very lightweight operation in memory, no need to fork to a thread
-            return ThreadPool.Names.SAME;
-        }
-
-        @Override
-        protected Response read(StreamInput in) throws IOException {
-            return new Response(in);
-        }
-
-        @Override
-        protected void masterOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
-            listener.onResponse(new Response()); // default implementation, overridden in specific tests
-        }
-
-        @Override
-        protected ClusterBlockException checkBlock(Request request, ClusterState state) {
-            return null; // default implementation, overridden in specific tests
-        }
-    }
-
-    public void testLocalOperationWithoutBlocks() throws ExecutionException, InterruptedException {
-        final boolean masterOperationFailure = randomBoolean();
-
-        Request request = new Request();
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-
-        final Exception exception = new Exception();
-        final Response response = new Response();
-
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
-
-        new Action("internal:testAction", transportService, clusterService, threadPool) {
-            @Override
-            protected void masterOperation(Task task, Request request, ClusterState state, ActionListener<Response> listener) {
-                if (masterOperationFailure) {
-                    listener.onFailure(exception);
-                } else {
-                    listener.onResponse(response);
-                }
-            }
-        }.execute(request, listener);
-        assertTrue(listener.isDone());
-
-        if (masterOperationFailure) {
-            try {
-                listener.get();
-                fail("Expected exception but returned proper result");
-            } catch (ExecutionException ex) {
-                assertThat(ex.getCause(), equalTo(exception));
-            }
-        } else {
-            assertThat(listener.get(), equalTo(response));
-        }
-    }
-
-    public void testLocalOperationWithBlocks() throws ExecutionException, InterruptedException {
-        final boolean retryableBlock = randomBoolean();
-        final boolean unblockBeforeTimeout = randomBoolean();
-
-        Request request = new Request().masterNodeTimeout(TimeValue.timeValueSeconds(unblockBeforeTimeout ? 60 : 0));
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-
-        ClusterBlock block = new ClusterBlock(1, "", retryableBlock, true, false, randomFrom(RestStatus.values()), ClusterBlockLevel.ALL);
-        ClusterState stateWithBlock = ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
-            .blocks(ClusterBlocks.builder().addGlobalBlock(block))
-            .build();
-        setState(clusterService, stateWithBlock);
-
-        new Action("internal:testAction", transportService, clusterService, threadPool) {
-            @Override
-            protected ClusterBlockException checkBlock(Request request, ClusterState state) {
-                Set<ClusterBlock> blocks = state.blocks().global();
-                return blocks.isEmpty() ? null : new ClusterBlockException(blocks);
-            }
-        }.execute(request, listener);
-
-        if (retryableBlock && unblockBeforeTimeout) {
-            assertFalse(listener.isDone());
-            setState(
-                clusterService,
-                ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
-                    .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
-                    .build()
-            );
-            assertTrue(listener.isDone());
-            listener.get();
-            return;
-        }
-
-        assertTrue(listener.isDone());
-        if (retryableBlock) {
-            try {
-                listener.get();
-                fail("Expected exception but returned proper result");
-            } catch (ExecutionException ex) {
-                assertThat(ex.getCause(), instanceOf(MasterNotDiscoveredException.class));
-                assertThat(ex.getCause().getCause(), instanceOf(ClusterBlockException.class));
-            }
-        } else {
-            assertListenerThrows("ClusterBlockException should be thrown", listener, ClusterBlockException.class);
-        }
-    }
-
-    public void testCheckBlockThrowsException() throws InterruptedException {
-        boolean throwExceptionOnRetry = randomBoolean();
-        Request request = new Request().masterNodeTimeout(TimeValue.timeValueSeconds(60));
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-
-        ClusterBlock block = new ClusterBlock(1, "", true, true, false, randomFrom(RestStatus.values()), ClusterBlockLevel.ALL);
-        ClusterState stateWithBlock = ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
-            .blocks(ClusterBlocks.builder().addGlobalBlock(block))
-            .build();
-        setState(clusterService, stateWithBlock);
-
-        new Action("internal:testAction", transportService, clusterService, threadPool) {
-            @Override
-            protected ClusterBlockException checkBlock(Request request, ClusterState state) {
-                Set<ClusterBlock> blocks = state.blocks().global();
-                if (throwExceptionOnRetry == false || blocks.isEmpty()) {
-                    throw new RuntimeException("checkBlock has thrown exception");
-                }
-                return new ClusterBlockException(blocks);
-
-            }
-        }.execute(request, listener);
-
-        if (throwExceptionOnRetry == false) {
-            assertListenerThrows("checkBlock has thrown exception", listener, RuntimeException.class);
-        } else {
-            assertFalse(listener.isDone());
-            setState(
-                clusterService,
-                ClusterState.builder(ClusterStateCreationUtils.state(localNode, localNode, allNodes))
-                    .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
-                    .build()
-            );
-            assertListenerThrows("checkBlock has thrown exception", listener, RuntimeException.class);
-        }
-    }
-
-    public void testForceLocalOperation() throws ExecutionException, InterruptedException {
-        Request request = new Request();
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, randomFrom(localNode, remoteNode, null), allNodes));
-
-        new Action("internal:testAction", transportService, clusterService, threadPool) {
-            @Override
-            protected boolean localExecute(Request request) {
-                return true;
-            }
-        }.execute(request, listener);
-
-        assertTrue(listener.isDone());
-        listener.get();
-    }
-
-    public void testMasterNotAvailable() throws ExecutionException, InterruptedException {
-        Request request = new Request().masterNodeTimeout(TimeValue.timeValueSeconds(0));
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, null, allNodes));
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
-        assertTrue(listener.isDone());
-        assertListenerThrows("MasterNotDiscoveredException should be thrown", listener, MasterNotDiscoveredException.class);
-    }
-
-    public void testMasterBecomesAvailable() throws ExecutionException, InterruptedException {
-        Request request = new Request();
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, null, allNodes));
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
-        assertFalse(listener.isDone());
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
-        assertTrue(listener.isDone());
-        listener.get();
-    }
-
-    public void testDelegateToMaster() throws ExecutionException, InterruptedException {
-        Request request = new Request();
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, remoteNode, allNodes));
-
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
-
-        assertThat(transport.capturedRequests().length, equalTo(1));
-        CapturingTransport.CapturedRequest capturedRequest = transport.capturedRequests()[0];
-        assertTrue(capturedRequest.node.isMasterNode());
-        assertThat(capturedRequest.request, equalTo(request));
-        assertThat(capturedRequest.action, equalTo("internal:testAction"));
-
-        Response response = new Response();
-        transport.handleResponse(capturedRequest.requestId, response);
-        assertTrue(listener.isDone());
-        assertThat(listener.get(), equalTo(response));
-    }
-
-    public void testDelegateToFailingMaster() throws ExecutionException, InterruptedException {
-        boolean failsWithConnectTransportException = randomBoolean();
-        boolean rejoinSameMaster = failsWithConnectTransportException && randomBoolean();
-        Request request = new Request().masterNodeTimeout(TimeValue.timeValueSeconds(failsWithConnectTransportException ? 60 : 0));
-        DiscoveryNode masterNode = this.remoteNode;
-        setState(
-            clusterService,
-            // use a random base version so it can go down when simulating a restart.
-            ClusterState.builder(ClusterStateCreationUtils.state(localNode, masterNode, allNodes)).version(randomIntBetween(0, 10))
-        );
-
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-        new Action("internal:testAction", transportService, clusterService, threadPool).execute(request, listener);
-
-        CapturingTransport.CapturedRequest[] capturedRequests = transport.getCapturedRequestsAndClear();
-        assertThat(capturedRequests.length, equalTo(1));
-        CapturingTransport.CapturedRequest capturedRequest = capturedRequests[0];
-        assertTrue(capturedRequest.node.isMasterNode());
-        assertThat(capturedRequest.request, equalTo(request));
-        assertThat(capturedRequest.action, equalTo("internal:testAction"));
-
-        if (rejoinSameMaster) {
-            transport.handleRemoteError(
-                capturedRequest.requestId,
-                randomBoolean() ? new ConnectTransportException(masterNode, "Fake error") : new NodeClosedException(masterNode)
-            );
-            assertFalse(listener.isDone());
-            if (randomBoolean()) {
-                // simulate master node removal
-                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
-                nodesBuilder.masterNodeId(null);
-                setState(clusterService, ClusterState.builder(clusterService.state()).nodes(nodesBuilder));
-            }
-            if (randomBoolean()) {
-                // reset the same state to increment a version simulating a join of an existing node
-                // simulating use being disconnected
-                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
-                nodesBuilder.masterNodeId(masterNode.getId());
-                setState(clusterService, ClusterState.builder(clusterService.state()).nodes(nodesBuilder));
-            } else {
-                // simulate master restart followed by a state recovery - this will reset the cluster state version
-                final DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
-                nodesBuilder.remove(masterNode);
-                masterNode = new DiscoveryNode(masterNode.getId(), masterNode.getAddress(), masterNode.getVersion());
-                nodesBuilder.add(masterNode);
-                nodesBuilder.masterNodeId(masterNode.getId());
-                final ClusterState.Builder builder = ClusterState.builder(clusterService.state()).nodes(nodesBuilder);
-                setState(clusterService, builder.version(0));
-            }
-            assertFalse(listener.isDone());
-            capturedRequests = transport.getCapturedRequestsAndClear();
-            assertThat(capturedRequests.length, equalTo(1));
-            capturedRequest = capturedRequests[0];
-            assertTrue(capturedRequest.node.isMasterNode());
-            assertThat(capturedRequest.request, equalTo(request));
-            assertThat(capturedRequest.action, equalTo("internal:testAction"));
-        } else if (failsWithConnectTransportException) {
-            transport.handleRemoteError(capturedRequest.requestId, new ConnectTransportException(masterNode, "Fake error"));
-            assertFalse(listener.isDone());
-            setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
-            assertTrue(listener.isDone());
-            listener.get();
-        } else {
-            OpenSearchException t = new OpenSearchException("test");
-            t.addHeader("header", "is here");
-            transport.handleRemoteError(capturedRequest.requestId, t);
-            assertTrue(listener.isDone());
-            try {
-                listener.get();
-                fail("Expected exception but returned proper result");
-            } catch (ExecutionException ex) {
-                final Throwable cause = ex.getCause().getCause();
-                assertThat(cause, instanceOf(OpenSearchException.class));
-                final OpenSearchException es = (OpenSearchException) cause;
-                assertThat(es.getMessage(), equalTo(t.getMessage()));
-                assertThat(es.getHeader("header"), equalTo(t.getHeader("header")));
-            }
-        }
-    }
-
-    public void testMasterFailoverAfterStepDown() throws ExecutionException, InterruptedException {
-        Request request = new Request().masterNodeTimeout(TimeValue.timeValueHours(1));
-        PlainActionFuture<Response> listener = new PlainActionFuture<>();
-
-        final Response response = new Response();
-
-        setState(clusterService, ClusterStateCreationUtils.state(localNode, localNode, allNodes));
-
-        new Action("internal:testAction", transportService, clusterService, threadPool) {
-            @Override
-            protected void masterOperation(Request request, ClusterState state, ActionListener<Response> listener) throws Exception {
-                // The other node has become master, simulate failures of this node while publishing cluster state through ZenDiscovery
-                setState(clusterService, ClusterStateCreationUtils.state(localNode, remoteNode, allNodes));
-                Exception failure = randomBoolean()
-                    ? new FailedToCommitClusterStateException("Fake error")
-                    : new NotMasterException("Fake error");
-                listener.onFailure(failure);
-            }
-        }.execute(request, listener);
-
-        assertThat(transport.capturedRequests().length, equalTo(1));
-        CapturingTransport.CapturedRequest capturedRequest = transport.capturedRequests()[0];
-        assertTrue(capturedRequest.node.isMasterNode());
-        assertThat(capturedRequest.request, equalTo(request));
-        assertThat(capturedRequest.action, equalTo("internal:testAction"));
-
-        transport.handleResponse(capturedRequest.requestId, response);
-        assertTrue(listener.isDone());
-        assertThat(listener.get(), equalTo(response));
-    }
-}
diff --git a/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionUtils.java b/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionUtils.java
deleted file mode 100644
index d1faeccc83ac4..0000000000000
--- a/server/src/test/java/org/opensearch/action/support/master/TransportMasterNodeActionUtils.java
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.action.support.master;
-
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
-import org.opensearch.cluster.ClusterState;
-
-public class TransportMasterNodeActionUtils {
-
-    /**
-     * Allows to directly call {@link TransportMasterNodeAction#masterOperation(MasterNodeRequest, ClusterState, ActionListener)} which is
-     * a protected method.
-     */
-    public static <Request extends MasterNodeRequest<Request>, Response extends ActionResponse> void runMasterOperation(
-        TransportMasterNodeAction<Request, Response> masterNodeAction,
-        Request request,
-        ClusterState clusterState,
-        ActionListener<Response> actionListener
-    ) throws Exception {
-        assert masterNodeAction.checkBlock(request, clusterState) == null;
-        masterNodeAction.masterOperation(request, clusterState, actionListener);
-    }
-}
diff --git a/server/src/test/java/org/opensearch/action/support/nodes/TransportNodesActionTests.java b/server/src/test/java/org/opensearch/action/support/nodes/TransportNodesActionTests.java
index 53ebceb25510a..10f9708072889 100644
--- a/server/src/test/java/org/opensearch/action/support/nodes/TransportNodesActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/nodes/TransportNodesActionTests.java
@@ -43,9 +43,10 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -99,7 +100,7 @@ public void testNodesSelectors() {
             nodeSelectors.add(randomFrom(NodeSelector.values()).selector);
         }
         int numNodeIds = randomIntBetween(0, 3);
-        String[] nodeIds = clusterService.state().nodes().getNodes().keys().toArray(String.class);
+        String[] nodeIds = clusterService.state().nodes().getNodes().keySet().toArray(new String[0]);
         for (int i = 0; i < numNodeIds; i++) {
             String nodeId = randomFrom(nodeIds);
             nodeSelectors.add(nodeId);
@@ -208,7 +209,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -226,7 +228,7 @@ public void setUp() throws Exception {
             discoveryNodes.add(node);
         }
         discoBuilder.localNodeId(randomFrom(discoveryNodes).getId());
-        discoBuilder.masterNodeId(randomFrom(discoveryNodes).getId());
+        discoBuilder.clusterManagerNodeId(randomFrom(discoveryNodes).getId());
         ClusterState.Builder stateBuilder = ClusterState.builder(clusterService.getClusterName());
         stateBuilder.nodes(discoBuilder);
         ClusterState clusterState = stateBuilder.build();
@@ -339,7 +341,7 @@ private static class DataNodesOnlyTransportNodesAction extends TestTransportNode
 
         @Override
         protected void resolveRequest(TestNodesRequest request, ClusterState clusterState) {
-            request.setConcreteNodes(clusterState.nodes().getDataNodes().values().toArray(DiscoveryNode.class));
+            request.setConcreteNodes(clusterState.nodes().getDataNodes().values().toArray(new DiscoveryNode[0]));
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/support/replication/BroadcastReplicationTests.java b/server/src/test/java/org/opensearch/action/support/replication/BroadcastReplicationTests.java
index 74810fa045790..19a9918fa4561 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/BroadcastReplicationTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/BroadcastReplicationTests.java
@@ -32,7 +32,6 @@
 package org.opensearch.action.support.replication;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.NoShardAvailableActionException;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
@@ -40,7 +39,6 @@
 import org.opensearch.action.admin.indices.flush.TransportFlushAction;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.broadcast.BroadcastRequest;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
@@ -49,19 +47,22 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.tasks.Task;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -115,7 +116,8 @@ public void setUp() throws Exception {
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            circuitBreakerService
+            circuitBreakerService,
+            NoopTracer.INSTANCE
         );
         clusterService = createClusterService(threadPool);
         transportService = new TransportService(
@@ -125,7 +127,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/support/replication/PendingReplicationActionsTests.java b/server/src/test/java/org/opensearch/action/support/replication/PendingReplicationActionsTests.java
index ec0cefed842cd..8fa4441bbd5ec 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/PendingReplicationActionsTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/PendingReplicationActionsTests.java
@@ -32,13 +32,14 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.RetryableAction;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexShardClosedException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.PrimaryShardClosedException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 
@@ -102,7 +103,7 @@ public void testAllocationIdActionWillBeCancelledOnClose() {
         pendingReplication.addPendingAction(allocationId, action);
         action.run();
         pendingReplication.close();
-        expectThrows(IndexShardClosedException.class, future::actionGet);
+        expectThrows(PrimaryShardClosedException.class, future::actionGet);
     }
 
     private class TestAction extends RetryableAction<Void> {
diff --git a/server/src/test/java/org/opensearch/action/support/replication/ReplicationOperationTests.java b/server/src/test/java/org/opensearch/action/support/replication/ReplicationOperationTests.java
index 8a4cdfc953bf8..6b54623b03164 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/ReplicationOperationTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/ReplicationOperationTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.action.support.PlainActionFuture;
@@ -45,20 +44,22 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.IndexShardNotStartedException;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
@@ -80,9 +81,13 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 
 import static org.opensearch.action.support.replication.ClusterStateCreationUtils.state;
 import static org.opensearch.action.support.replication.ClusterStateCreationUtils.stateWithActivePrimary;
+import static org.opensearch.action.support.replication.ReplicationOperation.RetryOnPrimaryException;
+import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
 import static org.hamcrest.Matchers.arrayWithSize;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
@@ -157,7 +162,14 @@ public void testReplication() throws Exception {
         final TestReplicaProxy replicasProxy = new TestReplicaProxy(simulatedFailures);
 
         final TestPrimary primary = new TestPrimary(primaryShard, () -> replicationGroup, threadPool);
-        final TestReplicationOperation op = new TestReplicationOperation(request, primary, listener, replicasProxy, primaryTerm);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicasProxy,
+            primaryTerm,
+            new FanoutReplicationProxy<>(replicasProxy)
+        );
         op.execute();
         assertThat("request was not processed on primary", request.processedOnPrimary.get(), equalTo(true));
         assertThat(request.processedOnReplicas, equalTo(expectedReplicas));
@@ -179,6 +191,199 @@ public void testReplication() throws Exception {
         assertThat(primary.knownGlobalCheckpoints, equalTo(replicasProxy.generatedGlobalCheckpoints));
     }
 
+    public void testReplicationWithRemoteTranslogEnabled() throws Exception {
+        Set<AllocationId> initializingIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> initializingIds.add(AllocationId.newInitializing()));
+        Set<AllocationId> activeIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> activeIds.add(AllocationId.newInitializing()));
+
+        AllocationId primaryId = activeIds.iterator().next();
+
+        ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder builder = new IndexShardRoutingTable.Builder(shardId);
+        final ShardRouting primaryShard = newShardRouting(
+            shardId,
+            nodeIdFromAllocationId(primaryId),
+            null,
+            true,
+            ShardRoutingState.STARTED,
+            primaryId
+        );
+        initializingIds.forEach(
+            aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.INITIALIZING, aId))
+        );
+        activeIds.stream()
+            .filter(aId -> !aId.equals(primaryId))
+            .forEach(
+                aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.STARTED, aId))
+            );
+        builder.addShard(primaryShard);
+        IndexShardRoutingTable routingTable = builder.build();
+
+        Set<String> inSyncAllocationIds = activeIds.stream().map(AllocationId::getId).collect(Collectors.toSet());
+        ReplicationGroup replicationGroup = new ReplicationGroup(routingTable, inSyncAllocationIds, inSyncAllocationIds, 0);
+        List<ShardRouting> replicationTargets = replicationGroup.getReplicationTargets();
+        assertEquals(inSyncAllocationIds.size(), replicationTargets.size());
+        assertTrue(
+            replicationTargets.stream().map(sh -> sh.allocationId().getId()).collect(Collectors.toSet()).containsAll(inSyncAllocationIds)
+        );
+
+        Request request = new Request(shardId);
+        PlainActionFuture<TestPrimary.Result> listener = new PlainActionFuture<>();
+        Map<ShardRouting, Exception> simulatedFailures = new HashMap<>();
+        TestReplicaProxy replicasProxy = new TestReplicaProxy(simulatedFailures);
+        TestPrimary primary = new TestPrimary(primaryShard, () -> replicationGroup, threadPool);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicasProxy,
+            0,
+            new ReplicationModeAwareProxy<>(ReplicationMode.NO_REPLICATION, replicasProxy, replicasProxy)
+        );
+        op.execute();
+        assertTrue("request was not processed on primary", request.processedOnPrimary.get());
+        assertEquals(0, request.processedOnReplicas.size());
+        assertEquals(0, replicasProxy.failedReplicas.size());
+        assertEquals(0, replicasProxy.markedAsStaleCopies.size());
+        assertTrue("post replication operations not run on primary", request.runPostReplicationActionsOnPrimary.get());
+        assertTrue("listener is not marked as done", listener.isDone());
+
+        ShardInfo shardInfo = listener.actionGet().getShardInfo();
+        assertEquals(1 + initializingIds.size(), shardInfo.getTotal());
+    }
+
+    public void testPrimaryToPrimaryReplicationWithRemoteTranslogEnabled() throws Exception {
+        Set<AllocationId> initializingIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> initializingIds.add(AllocationId.newInitializing()));
+        Set<AllocationId> activeIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> activeIds.add(AllocationId.newInitializing()));
+
+        AllocationId primaryId = AllocationId.newRelocation(AllocationId.newInitializing());
+        AllocationId relocationTargetId = AllocationId.newTargetRelocation(primaryId);
+
+        ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder builder = new IndexShardRoutingTable.Builder(shardId);
+        final ShardRouting primaryShard = newShardRouting(
+            shardId,
+            nodeIdFromAllocationId(primaryId),
+            nodeIdFromAllocationId(relocationTargetId),
+            true,
+            ShardRoutingState.RELOCATING,
+            primaryId
+        );
+        initializingIds.forEach(
+            aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.INITIALIZING, aId))
+        );
+        activeIds.forEach(
+            aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.STARTED, aId))
+        );
+        builder.addShard(primaryShard);
+        IndexShardRoutingTable routingTable = builder.build();
+
+        // Add primary and it's relocating target to activeIds
+        activeIds.add(primaryId);
+        activeIds.add(relocationTargetId);
+
+        Set<String> inSyncAllocationIds = activeIds.stream().map(AllocationId::getId).collect(Collectors.toSet());
+        ReplicationGroup replicationGroup = new ReplicationGroup(routingTable, inSyncAllocationIds, inSyncAllocationIds, 0);
+        List<ShardRouting> replicationTargets = replicationGroup.getReplicationTargets();
+        assertEquals(inSyncAllocationIds.size(), replicationTargets.size());
+        assertTrue(
+            replicationTargets.stream().map(sh -> sh.allocationId().getId()).collect(Collectors.toSet()).containsAll(inSyncAllocationIds)
+        );
+
+        Request request = new Request(shardId);
+        PlainActionFuture<TestPrimary.Result> listener = new PlainActionFuture<>();
+        Map<ShardRouting, Exception> simulatedFailures = new HashMap<>();
+        TestReplicaProxy replicasProxy = new TestReplicaProxy(simulatedFailures);
+        TestPrimary primary = new TestPrimary(primaryShard, () -> replicationGroup, threadPool);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicasProxy,
+            0,
+            new ReplicationModeAwareProxy<>(ReplicationMode.NO_REPLICATION, replicasProxy, replicasProxy)
+        );
+        op.execute();
+        assertTrue("request was not processed on primary", request.processedOnPrimary.get());
+        assertEquals(1, request.processedOnReplicas.size());
+        assertEquals(0, replicasProxy.failedReplicas.size());
+        assertEquals(0, replicasProxy.markedAsStaleCopies.size());
+        assertTrue("post replication operations not run on primary", request.runPostReplicationActionsOnPrimary.get());
+        assertTrue("listener is not marked as done", listener.isDone());
+
+        ShardInfo shardInfo = listener.actionGet().getShardInfo();
+        assertEquals(2 + initializingIds.size(), shardInfo.getTotal());
+    }
+
+    public void testForceReplicationWithRemoteTranslogEnabled() throws Exception {
+        Set<AllocationId> initializingIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> initializingIds.add(AllocationId.newInitializing()));
+        Set<AllocationId> activeIds = new HashSet<>();
+        IntStream.range(0, randomIntBetween(2, 5)).forEach(x -> activeIds.add(AllocationId.newInitializing()));
+
+        AllocationId primaryId = activeIds.iterator().next();
+
+        ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder builder = new IndexShardRoutingTable.Builder(shardId);
+        final ShardRouting primaryShard = newShardRouting(
+            shardId,
+            nodeIdFromAllocationId(primaryId),
+            null,
+            true,
+            ShardRoutingState.STARTED,
+            primaryId
+        );
+        initializingIds.forEach(
+            aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.INITIALIZING, aId))
+        );
+        activeIds.stream()
+            .filter(aId -> !aId.equals(primaryId))
+            .forEach(
+                aId -> builder.addShard(newShardRouting(shardId, nodeIdFromAllocationId(aId), null, false, ShardRoutingState.STARTED, aId))
+            );
+        builder.addShard(primaryShard);
+        IndexShardRoutingTable routingTable = builder.build();
+
+        Set<String> inSyncAllocationIds = activeIds.stream().map(AllocationId::getId).collect(Collectors.toSet());
+        ReplicationGroup replicationGroup = new ReplicationGroup(routingTable, inSyncAllocationIds, inSyncAllocationIds, 0);
+        List<ShardRouting> replicationTargets = replicationGroup.getReplicationTargets();
+        assertEquals(inSyncAllocationIds.size(), replicationTargets.size());
+        assertTrue(
+            replicationTargets.stream().map(sh -> sh.allocationId().getId()).collect(Collectors.toSet()).containsAll(inSyncAllocationIds)
+        );
+
+        Request request = new Request(shardId);
+        PlainActionFuture<TestPrimary.Result> listener = new PlainActionFuture<>();
+        Map<ShardRouting, Exception> simulatedFailures = new HashMap<>();
+        TestReplicaProxy replicasProxy = new TestReplicaProxy(simulatedFailures);
+        TestPrimary primary = new TestPrimary(primaryShard, () -> replicationGroup, threadPool);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicasProxy,
+            0,
+            new FanoutReplicationProxy<>(replicasProxy)
+        );
+        op.execute();
+        assertTrue("request was not processed on primary", request.processedOnPrimary.get());
+        assertEquals(activeIds.size() - 1, request.processedOnReplicas.size());
+        assertEquals(0, replicasProxy.failedReplicas.size());
+        assertEquals(0, replicasProxy.markedAsStaleCopies.size());
+        assertTrue("post replication operations not run on primary", request.runPostReplicationActionsOnPrimary.get());
+        assertTrue("listener is not marked as done", listener.isDone());
+
+        ShardInfo shardInfo = listener.actionGet().getShardInfo();
+        assertEquals(activeIds.size() + initializingIds.size(), shardInfo.getTotal());
+    }
+
+    static String nodeIdFromAllocationId(final AllocationId allocationId) {
+        return "n-" + allocationId.getId().substring(0, 8);
+    }
+
     public void testRetryTransientReplicationFailure() throws Exception {
         final String index = "test";
         final ShardId shardId = new ShardId(index, "_na_", 0);
@@ -242,7 +447,8 @@ public void testRetryTransientReplicationFailure() throws Exception {
             replicasProxy,
             primaryTerm,
             TimeValue.timeValueMillis(20),
-            TimeValue.timeValueSeconds(60)
+            TimeValue.timeValueSeconds(60),
+            new FanoutReplicationProxy<>(replicasProxy)
         );
         op.execute();
         assertThat("request was not processed on primary", request.processedOnPrimary.get(), equalTo(true));
@@ -379,7 +585,14 @@ public void failShard(String message, Exception exception) {
                 assertTrue(primaryFailed.compareAndSet(false, true));
             }
         };
-        final TestReplicationOperation op = new TestReplicationOperation(request, primary, listener, replicasProxy, primaryTerm);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicasProxy,
+            primaryTerm,
+            new FanoutReplicationProxy<>(replicasProxy)
+        );
         op.execute();
 
         assertThat("request was not processed on primary", request.processedOnPrimary.get(), equalTo(true));
@@ -389,7 +602,7 @@ public void failShard(String message, Exception exception) {
         } else {
             assertFalse(primaryFailed.get());
         }
-        assertListenerThrows("should throw exception to trigger retry", listener, ReplicationOperation.RetryOnPrimaryException.class);
+        assertListenerThrows("should throw exception to trigger retry", listener, RetryOnPrimaryException.class);
     }
 
     public void testAddedReplicaAfterPrimaryOperation() throws Exception {
@@ -438,7 +651,14 @@ public void perform(Request request, ActionListener<Result> listener) {
 
         Request request = new Request(shardId);
         PlainActionFuture<TestPrimary.Result> listener = new PlainActionFuture<>();
-        final TestReplicationOperation op = new TestReplicationOperation(request, primary, listener, new TestReplicaProxy(), primaryTerm);
+        final TestReplicationOperation op = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            new TestReplicaProxy(),
+            primaryTerm,
+            new FanoutReplicationProxy<>(new TestReplicaProxy())
+        );
         op.execute();
 
         assertThat("request was not processed on primary", request.processedOnPrimary.get(), equalTo(true));
@@ -493,7 +713,8 @@ public void testWaitForActiveShards() throws Exception {
             logger,
             threadPool,
             "test",
-            primaryTerm
+            primaryTerm,
+            new FanoutReplicationProxy<>(new TestReplicaProxy())
         );
 
         if (passesActiveShardCheck) {
@@ -554,7 +775,14 @@ public void updateLocalCheckpointForShard(String allocationId, long checkpoint)
 
         final PlainActionFuture<TestPrimary.Result> listener = new PlainActionFuture<>();
         final ReplicationOperation.Replicas<Request> replicas = new TestReplicaProxy(Collections.emptyMap());
-        TestReplicationOperation operation = new TestReplicationOperation(request, primary, listener, replicas, primaryTerm);
+        TestReplicationOperation operation = new TestReplicationOperation(
+            request,
+            primary,
+            listener,
+            replicas,
+            primaryTerm,
+            new FanoutReplicationProxy<>(replicas)
+        );
         operation.execute();
 
         assertThat(primaryFailed.get(), equalTo(fatal));
@@ -841,7 +1069,8 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
             Replicas<Request> replicas,
             long primaryTerm,
             TimeValue initialRetryBackoffBound,
-            TimeValue retryTimeout
+            TimeValue retryTimeout,
+            ReplicationProxy<Request> replicationProxy
         ) {
             this(
                 request,
@@ -853,7 +1082,8 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
                 "test",
                 primaryTerm,
                 initialRetryBackoffBound,
-                retryTimeout
+                retryTimeout,
+                replicationProxy
             );
         }
 
@@ -862,9 +1092,20 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
             Primary<Request, Request, TestPrimary.Result> primary,
             ActionListener<TestPrimary.Result> listener,
             Replicas<Request> replicas,
-            long primaryTerm
+            long primaryTerm,
+            ReplicationProxy<Request> replicationProxy
         ) {
-            this(request, primary, listener, replicas, ReplicationOperationTests.this.logger, threadPool, "test", primaryTerm);
+            this(
+                request,
+                primary,
+                listener,
+                replicas,
+                ReplicationOperationTests.this.logger,
+                threadPool,
+                "test",
+                primaryTerm,
+                replicationProxy
+            );
         }
 
         TestReplicationOperation(
@@ -875,7 +1116,8 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
             Logger logger,
             ThreadPool threadPool,
             String opType,
-            long primaryTerm
+            long primaryTerm,
+            ReplicationProxy<Request> replicationProxy
         ) {
             this(
                 request,
@@ -887,7 +1129,8 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
                 opType,
                 primaryTerm,
                 TimeValue.timeValueMillis(50),
-                TimeValue.timeValueSeconds(1)
+                TimeValue.timeValueSeconds(1),
+                replicationProxy
             );
         }
 
@@ -901,9 +1144,22 @@ class TestReplicationOperation extends ReplicationOperation<Request, Request, Te
             String opType,
             long primaryTerm,
             TimeValue initialRetryBackoffBound,
-            TimeValue retryTimeout
+            TimeValue retryTimeout,
+            ReplicationProxy<Request> replicationProxy
         ) {
-            super(request, primary, listener, replicas, logger, threadPool, opType, primaryTerm, initialRetryBackoffBound, retryTimeout);
+            super(
+                request,
+                primary,
+                listener,
+                replicas,
+                logger,
+                threadPool,
+                opType,
+                primaryTerm,
+                initialRetryBackoffBound,
+                retryTimeout,
+                replicationProxy
+            );
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/support/replication/ReplicationResponseTests.java b/server/src/test/java/org/opensearch/action/support/replication/ReplicationResponseTests.java
index 89d0dfe36ca0f..ee92126a3d72e 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/ReplicationResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/ReplicationResponseTests.java
@@ -34,16 +34,17 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.support.replication.ReplicationResponse.ShardInfo;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -51,7 +52,7 @@
 import java.util.Locale;
 
 import static org.opensearch.OpenSearchExceptionTests.assertDeepEquals;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class ReplicationResponseTests extends OpenSearchTestCase {
@@ -66,7 +67,7 @@ public void testShardInfoToString() {
     public void testShardInfoToXContent() throws IOException {
         {
             ShardInfo shardInfo = new ShardInfo(5, 3);
-            String output = Strings.toString(shardInfo);
+            String output = Strings.toString(MediaTypeRegistry.JSON, shardInfo);
             assertEquals("{\"total\":5,\"successful\":3,\"failed\":0}", output);
         }
         {
@@ -88,7 +89,7 @@ public void testShardInfoToXContent() throws IOException {
                     true
                 )
             );
-            String output = Strings.toString(shardInfo);
+            String output = Strings.toString(MediaTypeRegistry.JSON, shardInfo);
             assertEquals(
                 "{\"total\":6,\"successful\":4,\"failed\":2,\"failures\":[{\"_index\":\"index\",\"_shard\":3,"
                     + "\"_node\":\"_node_id\",\"reason\":{\"type\":\"illegal_argument_exception\",\"reason\":\"Wrong\"},"
diff --git a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationActionTests.java b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationActionTests.java
index 696958c340375..03150d6e30755 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationActionTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.UnavailableShardsException;
 import org.opensearch.action.admin.indices.close.CloseIndexRequest;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
@@ -64,28 +63,31 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardClosedException;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.indices.IndexClosedException;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.cluster.ClusterStateChanges;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.test.transport.MockTransportService;
@@ -96,7 +98,6 @@
 import org.opensearch.transport.TransportChannel;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 import org.opensearch.transport.nio.MockNioTransport;
 import org.hamcrest.Matcher;
@@ -138,9 +139,9 @@
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyLong;
 import static org.mockito.Mockito.anyString;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -195,12 +196,19 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
         shardStateAction = new ShardStateAction(clusterService, transportService, null, null, threadPool);
         action = new TestAction(Settings.EMPTY, "internal:testAction", transportService, clusterService, shardStateAction, threadPool);
+        Metadata metadata = Metadata.builder().build();
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .nodes(clusterService.state().nodes())
+            .build();
+        setState(clusterService, clusterState);
     }
 
     @Override
@@ -950,7 +958,8 @@ public void testSeqNoIsSetOnPrimary() {
         Set<String> inSyncIds = randomBoolean()
             ? singleton(routingEntry.allocationId().getId())
             : clusterService.state().metadata().index(index).inSyncAllocationIds(0);
-        ReplicationGroup replicationGroup = new ReplicationGroup(shardRoutingTable, inSyncIds, shardRoutingTable.getAllAllocationIds(), 0);
+        Set<String> trackedAllocationIds = shardRoutingTable.getAllAllocationIds();
+        ReplicationGroup replicationGroup = new ReplicationGroup(shardRoutingTable, inSyncIds, trackedAllocationIds, 0);
         when(shard.getReplicationGroup()).thenReturn(replicationGroup);
         PendingReplicationActions replicationActions = new PendingReplicationActions(shardId, threadPool);
         replicationActions.accept(replicationGroup);
@@ -1309,7 +1318,8 @@ public void testRetryOnReplicaWithRealTransport() throws Exception {
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             namedWriteableRegistry,
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         );
         transportService = new MockTransportService(
             Settings.EMPTY,
@@ -1318,7 +1328,8 @@ public void testRetryOnReplicaWithRealTransport() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
index b034b335bd9a3..839ac7ab5bb92 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
@@ -31,9 +31,7 @@
 
 package org.opensearch.action.support.replication;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterState;
@@ -54,17 +52,20 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.InternalEngineFactory;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
@@ -142,7 +143,7 @@ public void setUp() throws Exception {
         Set<DiscoveryNodeRole> roles = new HashSet<>(DiscoveryNodeRole.BUILT_IN_ROLES);
         DiscoveryNode node1 = new DiscoveryNode("_name1", "_node1", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
         DiscoveryNode node2 = new DiscoveryNode("_name2", "_node2", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
-        state.nodes(DiscoveryNodes.builder().add(node1).add(node2).localNodeId(node1.getId()).masterNodeId(node1.getId()));
+        state.nodes(DiscoveryNodes.builder().add(node1).add(node2).localNodeId(node1.getId()).clusterManagerNodeId(node1.getId()));
 
         shardId = new ShardId("index", UUID.randomUUID().toString(), 0);
         ShardRouting shardRouting = newShardRouting(
@@ -232,7 +233,8 @@ public String executor() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             bta -> node1,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionForIndexingPressureTests.java b/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionForIndexingPressureTests.java
index 3aae1ee40818d..4a2185d1558f7 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionForIndexingPressureTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionForIndexingPressureTests.java
@@ -5,7 +5,6 @@
 
 package org.opensearch.action.support.replication;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.PlainActionFuture;
@@ -18,30 +17,32 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.ShardIndexingPressureSettings;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.ReplicationGroup;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.index.stats.IndexingPressurePerShardStats;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportChannel;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 import org.hamcrest.Matcher;
 import org.junit.After;
@@ -102,7 +103,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionTests.java b/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionTests.java
index 4da32a890fd0e..9d2069ac16190 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/TransportWriteActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.support.replication;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
 import org.opensearch.action.support.PlainActionFuture;
@@ -50,19 +49,23 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.PrimaryShardClosedException;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.node.NodeClosedException;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
@@ -70,13 +73,12 @@
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -90,9 +92,12 @@
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
+import org.mockito.ArgumentCaptor;
+
 import static java.util.Collections.emptyMap;
 import static org.opensearch.test.ClusterServiceUtils.createClusterService;
 import static org.hamcrest.Matchers.arrayWithSize;
+import static org.hamcrest.Matchers.emptyArray;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.mockito.Mockito.any;
@@ -284,7 +289,8 @@ public void testReplicaProxy() throws InterruptedException, ExecutionException {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -395,6 +401,49 @@ public void testReplicaProxy() throws InterruptedException, ExecutionException {
         }
     }
 
+    public void testPrimaryClosedDoesNotFailShard() {
+        final CapturingTransport transport = new CapturingTransport();
+        final TransportService transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            x -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        final ShardStateAction shardStateAction = new ShardStateAction(clusterService, transportService, null, null, threadPool);
+        final TestAction action = new TestAction(
+            Settings.EMPTY,
+            "internal:testAction",
+            transportService,
+            clusterService,
+            shardStateAction,
+            threadPool
+        );
+        final String index = "test";
+        final ShardId shardId = new ShardId(index, "_na_", 0);
+        final ClusterState state = ClusterStateCreationUtils.stateWithActivePrimary(index, true, 1, 0);
+        ClusterServiceUtils.setState(clusterService, state);
+        final long primaryTerm = state.metadata().index(index).primaryTerm(0);
+        final ShardRouting shardRouting = state.routingTable().shardRoutingTable(shardId).replicaShards().get(0);
+
+        // Assert that failShardIfNeeded is a no-op for the PrimaryShardClosedException failure
+        final AtomicInteger callbackCount = new AtomicInteger(0);
+        action.newReplicasProxy()
+            .failShardIfNeeded(
+                shardRouting,
+                primaryTerm,
+                "test",
+                new PrimaryShardClosedException(shardId),
+                ActionListener.wrap(callbackCount::incrementAndGet)
+            );
+        MatcherAssert.assertThat(transport.getCapturedRequestsAndClear(), emptyArray());
+        MatcherAssert.assertThat(callbackCount.get(), equalTo(0));
+    }
+
     private class TestAction extends TransportWriteAction<TestRequest, TestRequest, TestResponse> {
 
         private final boolean withDocumentFailureOnPrimary;
@@ -415,7 +464,8 @@ protected TestAction(boolean withDocumentFailureOnPrimary, boolean withDocumentF
                     TransportService.NOOP_TRANSPORT_INTERCEPTOR,
                     x -> null,
                     null,
-                    Collections.emptySet()
+                    Collections.emptySet(),
+                    NoopTracer.INSTANCE
                 ),
                 TransportWriteActionTests.this.clusterService,
                 null,
diff --git a/server/src/test/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationActionTests.java b/server/src/test/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationActionTests.java
index b12ecb86c8e76..118b4e596fc66 100644
--- a/server/src/test/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationActionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/single/instance/TransportInstanceSingleOperationActionTests.java
@@ -33,8 +33,6 @@
 package org.opensearch.action.support.single.instance;
 
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.PlainActionFuture;
@@ -49,14 +47,17 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -188,7 +189,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
diff --git a/server/src/test/java/org/opensearch/action/termvectors/AbstractTermVectorsTestCase.java b/server/src/test/java/org/opensearch/action/termvectors/AbstractTermVectorsTestCase.java
index d9613176c0156..a38e90911e201 100644
--- a/server/src/test/java/org/opensearch/action/termvectors/AbstractTermVectorsTestCase.java
+++ b/server/src/test/java/org/opensearch/action/termvectors/AbstractTermVectorsTestCase.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.action.termvectors;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.CharArraySet;
 import org.apache.lucene.analysis.LowerCaseFilter;
@@ -62,22 +64,43 @@
 import org.apache.lucene.store.Directory;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 
-public abstract class AbstractTermVectorsTestCase extends OpenSearchIntegTestCase {
+public abstract class AbstractTermVectorsTestCase extends ParameterizedOpenSearchIntegTestCase {
+
+    public AbstractTermVectorsTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     protected static class TestFieldSetting {
         public final String name;
         public final boolean storedOffset;
diff --git a/server/src/test/java/org/opensearch/action/termvectors/GetTermVectorsTests.java b/server/src/test/java/org/opensearch/action/termvectors/GetTermVectorsTests.java
index 1217efb883468..7dd73966bb079 100644
--- a/server/src/test/java/org/opensearch/action/termvectors/GetTermVectorsTests.java
+++ b/server/src/test/java/org/opensearch/action/termvectors/GetTermVectorsTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.termvectors;
 
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.payloads.FloatEncoder;
@@ -45,10 +44,11 @@
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.PreConfiguredTokenizer;
 import org.opensearch.index.analysis.TokenFilterFactory;
 import org.opensearch.indices.analysis.AnalysisModule;
diff --git a/server/src/test/java/org/opensearch/action/termvectors/TermVectorsUnitTests.java b/server/src/test/java/org/opensearch/action/termvectors/TermVectorsUnitTests.java
index 089dfcaf65517..31366ee3f65ad 100644
--- a/server/src/test/java/org/opensearch/action/termvectors/TermVectorsUnitTests.java
+++ b/server/src/test/java/org/opensearch/action/termvectors/TermVectorsUnitTests.java
@@ -51,16 +51,16 @@
 import org.apache.lucene.store.Directory;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.action.termvectors.TermVectorsRequest.Flag;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.document.RestTermVectorsAction;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.StreamsUtils;
 import org.hamcrest.Matchers;
@@ -247,7 +247,7 @@ public void testStreamRequest() throws IOException {
             request.termStatistics(random().nextBoolean());
             String pref = random().nextBoolean() ? "somePreference" : null;
             request.preference(pref);
-            request.doc(new BytesArray("{}"), randomBoolean(), XContentType.JSON);
+            request.doc(new BytesArray("{}"), randomBoolean(), MediaTypeRegistry.JSON);
 
             // write
             ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
@@ -267,7 +267,7 @@ public void testStreamRequest() throws IOException {
             assertThat(request.preference(), equalTo(pref));
             assertThat(request.routing(), equalTo(null));
             assertEquals(new BytesArray("{}"), request.doc());
-            assertEquals(XContentType.JSON, request.xContentType());
+            assertEquals(MediaTypeRegistry.JSON, request.xContentType());
         }
     }
 
@@ -281,7 +281,7 @@ public void testStreamRequestLegacyVersion() throws IOException {
             request.termStatistics(random().nextBoolean());
             String pref = random().nextBoolean() ? "somePreference" : null;
             request.preference(pref);
-            request.doc(new BytesArray("{}"), randomBoolean(), XContentType.JSON);
+            request.doc(new BytesArray("{}"), randomBoolean(), MediaTypeRegistry.JSON);
 
             // write using older version which contains types
             ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
@@ -313,7 +313,7 @@ public void testStreamRequestLegacyVersion() throws IOException {
             assertThat(request.preference(), equalTo(pref));
             assertThat(request.routing(), equalTo(null));
             assertEquals(new BytesArray("{}"), request.doc());
-            assertEquals(XContentType.JSON, request.xContentType());
+            assertEquals(MediaTypeRegistry.JSON, request.xContentType());
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/action/termvectors/TransportMultiTermVectorsActionTests.java b/server/src/test/java/org/opensearch/action/termvectors/TransportMultiTermVectorsActionTests.java
index b62050a1b8050..0868421fe1d41 100644
--- a/server/src/test/java/org/opensearch/action/termvectors/TransportMultiTermVectorsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/termvectors/TransportMultiTermVectorsActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.termvectors;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.IndicesRequest;
 import org.opensearch.action.RoutingMissingException;
 import org.opensearch.action.get.TransportMultiGetActionTests;
@@ -48,19 +47,21 @@
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -80,8 +81,8 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.eq;
-import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.when;
 
 public class TransportMultiTermVectorsActionTests extends OpenSearchTestCase {
@@ -107,7 +108,8 @@ public static void beforeClass() throws Exception {
                 randomBase64UUID()
             ),
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public TaskManager getTaskManager() {
@@ -140,7 +142,7 @@ public TaskManager getTaskManager() {
                                         .endObject()
                                 ),
                                 true,
-                                XContentType.JSON
+                                MediaTypeRegistry.JSON
                             )
                         )
                 )
@@ -165,7 +167,7 @@ public TaskManager getTaskManager() {
                                             .endObject()
                                     ),
                                     true,
-                                    XContentType.JSON
+                                    MediaTypeRegistry.JSON
                                 )
                             )
                     )
diff --git a/server/src/test/java/org/opensearch/action/update/UpdateRequestTests.java b/server/src/test/java/org/opensearch/action/update/UpdateRequestTests.java
index 380b0628147de..b70fda0d86240 100644
--- a/server/src/test/java/org/opensearch/action/update/UpdateRequestTests.java
+++ b/server/src/test/java/org/opensearch/action/update/UpdateRequestTests.java
@@ -37,22 +37,23 @@
 import org.opensearch.action.delete.DeleteRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.replication.ReplicationRequest;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.index.get.GetResult;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptEngine;
@@ -71,7 +72,7 @@
 
 import static java.util.Collections.emptyMap;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 import static org.opensearch.script.MockScriptEngine.mockInlineScript;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
@@ -514,7 +515,7 @@ public void testToValidateUpsertRequestAndCAS() {
         UpdateRequest updateRequest = new UpdateRequest("index", "id");
         updateRequest.setIfSeqNo(1L);
         updateRequest.setIfPrimaryTerm(1L);
-        updateRequest.doc("{}", XContentType.JSON);
+        updateRequest.doc("{}", MediaTypeRegistry.JSON);
         updateRequest.upsert(new IndexRequest("index").id("id"));
         assertThat(
             updateRequest.validate().validationErrors(),
@@ -524,7 +525,7 @@ public void testToValidateUpsertRequestAndCAS() {
 
     public void testToValidateUpsertRequestWithVersion() {
         UpdateRequest updateRequest = new UpdateRequest("index", "id");
-        updateRequest.doc("{}", XContentType.JSON);
+        updateRequest.doc("{}", MediaTypeRegistry.JSON);
         updateRequest.upsert(new IndexRequest("index").id("1").version(1L));
         assertThat(updateRequest.validate().validationErrors(), contains("can't provide version in upsert request"));
     }
@@ -532,7 +533,7 @@ public void testToValidateUpsertRequestWithVersion() {
     public void testValidate() {
         {
             UpdateRequest request = new UpdateRequest("index", "id");
-            request.doc("{}", XContentType.JSON);
+            request.doc("{}", MediaTypeRegistry.JSON);
             ActionRequestValidationException validate = request.validate();
 
             assertThat(validate, nullValue());
@@ -540,7 +541,7 @@ public void testValidate() {
         {
             // Null types are defaulted to "_doc"
             UpdateRequest request = new UpdateRequest("index", null);
-            request.doc("{}", XContentType.JSON);
+            request.doc("{}", MediaTypeRegistry.JSON);
             ActionRequestValidationException validate = request.validate();
 
             assertThat(validate, not(nullValue()));
diff --git a/server/src/test/java/org/opensearch/action/update/UpdateResponseTests.java b/server/src/test/java/org/opensearch/action/update/UpdateResponseTests.java
index ba0abd6c8e349..f6e0c9ae7c61a 100644
--- a/server/src/test/java/org/opensearch/action/update/UpdateResponseTests.java
+++ b/server/src/test/java/org/opensearch/action/update/UpdateResponseTests.java
@@ -35,18 +35,19 @@
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.index.IndexResponseTests;
 import org.opensearch.action.support.replication.ReplicationResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.index.get.GetResultTests;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -60,7 +61,7 @@
 import static org.opensearch.action.DocWriteResponse.Result.NOT_FOUND;
 import static org.opensearch.action.DocWriteResponse.Result.UPDATED;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_UUID_NA_VALUE;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -69,7 +70,7 @@ public class UpdateResponseTests extends OpenSearchTestCase {
     public void testToXContent() throws IOException {
         {
             UpdateResponse updateResponse = new UpdateResponse(new ShardId("index", "index_uuid", 0), "id", -2, 0, 0, NOT_FOUND);
-            String output = Strings.toString(updateResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, updateResponse);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":0,\"result\":\"not_found\","
                     + "\"_shards\":{\"total\":0,\"successful\":0,\"failed\":0}}",
@@ -86,7 +87,7 @@ public void testToXContent() throws IOException {
                 1,
                 DELETED
             );
-            String output = Strings.toString(updateResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, updateResponse);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":1,\"result\":\"deleted\","
                     + "\"_shards\":{\"total\":10,\"successful\":6,\"failed\":0},\"_seq_no\":3,\"_primary_term\":17}",
@@ -110,7 +111,7 @@ public void testToXContent() throws IOException {
             );
             updateResponse.setGetResult(new GetResult("books", "1", 0, 1, 2, true, source, fields, null));
 
-            String output = Strings.toString(updateResponse);
+            String output = Strings.toString(MediaTypeRegistry.JSON, updateResponse);
             assertEquals(
                 "{\"_index\":\"books\",\"_id\":\"1\",\"_version\":2,\"result\":\"updated\","
                     + "\"_shards\":{\"total\":3,\"successful\":2,\"failed\":0},\"_seq_no\":7,\"_primary_term\":17,\"get\":{"
@@ -136,13 +137,13 @@ public void testFromXContentWithRandomFields() throws IOException {
     }
 
     private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws IOException {
-        final XContentType xContentType = randomFrom(XContentType.JSON);
-        final Tuple<UpdateResponse, UpdateResponse> tuple = randomUpdateResponse(xContentType);
+        final MediaType mediaType = randomFrom(MediaTypeRegistry.JSON);
+        final Tuple<UpdateResponse, UpdateResponse> tuple = randomUpdateResponse(mediaType);
         UpdateResponse updateResponse = tuple.v1();
         UpdateResponse expectedUpdateResponse = tuple.v2();
 
         boolean humanReadable = randomBoolean();
-        BytesReference originalBytes = toShuffledXContent(updateResponse, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
+        BytesReference originalBytes = toShuffledXContent(updateResponse, mediaType, ToXContent.EMPTY_PARAMS, humanReadable);
 
         BytesReference mutated;
         if (addRandomFields) {
@@ -155,12 +156,12 @@ private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws
             // object since this is where GetResult's metadata fields are rendered out and they would be parsed back as
             // extra metadata fields.
             Predicate<String> excludeFilter = path -> path.contains("reason") || path.contains("get");
-            mutated = insertRandomFields(xContentType, originalBytes, excludeFilter, random());
+            mutated = insertRandomFields(mediaType, originalBytes, excludeFilter, random());
         } else {
             mutated = originalBytes;
         }
         UpdateResponse parsedUpdateResponse;
-        try (XContentParser parser = createParser(xContentType.xContent(), mutated)) {
+        try (XContentParser parser = createParser(mediaType.xContent(), mutated)) {
             parsedUpdateResponse = UpdateResponse.fromXContent(parser);
             assertNull(parser.nextToken());
         }
@@ -173,9 +174,9 @@ private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws
         // Prints out the parsed UpdateResponse object to verify that it is the same as the expected output.
         // If random fields have been inserted, it checks that they have been filtered out and that they do
         // not alter the final output of the parsed object.
-        BytesReference parsedBytes = toXContent(parsedUpdateResponse, xContentType, humanReadable);
-        BytesReference expectedBytes = toXContent(expectedUpdateResponse, xContentType, humanReadable);
-        assertToXContentEquivalent(expectedBytes, parsedBytes, xContentType);
+        BytesReference parsedBytes = toXContent(parsedUpdateResponse, mediaType, humanReadable);
+        BytesReference expectedBytes = toXContent(expectedUpdateResponse, mediaType, humanReadable);
+        assertToXContentEquivalent(expectedBytes, parsedBytes, mediaType);
     }
 
     /**
@@ -184,8 +185,8 @@ private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws
      * The left element is the actual {@link UpdateResponse} to serialize while the right element is the
      * expected {@link UpdateResponse} after parsing.
      */
-    public static Tuple<UpdateResponse, UpdateResponse> randomUpdateResponse(XContentType xContentType) {
-        Tuple<GetResult, GetResult> getResults = GetResultTests.randomGetResult(xContentType);
+    public static Tuple<UpdateResponse, UpdateResponse> randomUpdateResponse(MediaType mediaType) {
+        Tuple<GetResult, GetResult> getResults = GetResultTests.randomGetResult(mediaType);
         GetResult actualGetResult = getResults.v1();
         GetResult expectedGetResult = getResults.v2();
 
diff --git a/server/src/test/java/org/opensearch/bootstrap/BootstrapChecksTests.java b/server/src/test/java/org/opensearch/bootstrap/BootstrapChecksTests.java
index d941c624509da..69102d2e76bef 100644
--- a/server/src/test/java/org/opensearch/bootstrap/BootstrapChecksTests.java
+++ b/server/src/test/java/org/opensearch/bootstrap/BootstrapChecksTests.java
@@ -36,23 +36,28 @@
 import org.apache.lucene.util.Constants;
 import org.opensearch.cluster.coordination.ClusterBootstrapService;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.discovery.SettingsBasedSeedHostsProvider;
+import org.opensearch.env.Environment;
 import org.opensearch.monitor.jvm.JvmInfo;
+import org.opensearch.node.NodeRoleSettings;
 import org.opensearch.node.NodeValidationException;
 import org.opensearch.test.AbstractBootstrapCheckTestCase;
 import org.hamcrest.Matcher;
 
+import java.lang.Runtime.Version;
 import java.net.InetAddress;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
@@ -654,81 +659,6 @@ String javaVersion() {
 
     }
 
-    public void testG1GCCheck() throws NodeValidationException {
-        final AtomicBoolean isG1GCEnabled = new AtomicBoolean(true);
-        final AtomicBoolean isJava8 = new AtomicBoolean(true);
-        final AtomicReference<String> jvmVersion = new AtomicReference<>(
-            String.format(Locale.ROOT, "25.%d-b%d", randomIntBetween(0, 39), randomIntBetween(1, 128))
-        );
-        final BootstrapChecks.G1GCCheck g1GCCheck = new BootstrapChecks.G1GCCheck() {
-
-            @Override
-            String jvmVendor() {
-                return "Oracle Corporation";
-            }
-
-            @Override
-            boolean isG1GCEnabled() {
-                return isG1GCEnabled.get();
-            }
-
-            @Override
-            String jvmVersion() {
-                return jvmVersion.get();
-            }
-
-            @Override
-            boolean isJava8() {
-                return isJava8.get();
-            }
-
-        };
-
-        final NodeValidationException e = expectThrows(
-            NodeValidationException.class,
-            () -> BootstrapChecks.check(emptyContext, true, Collections.singletonList(g1GCCheck))
-        );
-        assertThat(
-            e.getMessage(),
-            containsString(
-                "JVM version [" + jvmVersion.get() + "] can cause data corruption when used with G1GC; upgrade to at least Java 8u40"
-            )
-        );
-
-        // if G1GC is disabled, nothing should happen
-        isG1GCEnabled.set(false);
-        BootstrapChecks.check(emptyContext, true, Collections.singletonList(g1GCCheck));
-
-        // if on or after update 40, nothing should happen independent of whether or not G1GC is enabled
-        isG1GCEnabled.set(randomBoolean());
-        jvmVersion.set(String.format(Locale.ROOT, "25.%d-b%d", randomIntBetween(40, 112), randomIntBetween(1, 128)));
-        BootstrapChecks.check(emptyContext, true, Collections.singletonList(g1GCCheck));
-
-        final BootstrapChecks.G1GCCheck nonOracleCheck = new BootstrapChecks.G1GCCheck() {
-
-            @Override
-            String jvmVendor() {
-                return randomAlphaOfLength(8);
-            }
-
-        };
-
-        // if not on an Oracle JVM, nothing should happen
-        BootstrapChecks.check(emptyContext, true, Collections.singletonList(nonOracleCheck));
-
-        final BootstrapChecks.G1GCCheck nonJava8Check = new BootstrapChecks.G1GCCheck() {
-
-            @Override
-            boolean isJava8() {
-                return false;
-            }
-
-        };
-
-        // if not Java 8, nothing should happen
-        BootstrapChecks.check(emptyContext, true, Collections.singletonList(nonJava8Check));
-    }
-
     public void testAllPermissionCheck() throws NodeValidationException {
         final AtomicBoolean isAllPermissionGranted = new AtomicBoolean(true);
         final BootstrapChecks.AllPermissionCheck allPermissionCheck = new BootstrapChecks.AllPermissionCheck() {
@@ -818,5 +748,72 @@ public void testDiscoveryConfiguredCheck() throws NodeValidationException {
         ensureChecksPass.accept(Settings.builder().putList(ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey()));
         ensureChecksPass.accept(Settings.builder().putList(DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING.getKey()));
         ensureChecksPass.accept(Settings.builder().putList(SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING.getKey()));
+        // Validate the deprecated setting is still valid during the node bootstrap.
+        ensureChecksPass.accept(Settings.builder().putList(ClusterBootstrapService.INITIAL_MASTER_NODES_SETTING.getKey()));
+    }
+
+    public void testJvmVersionCheck() throws NodeValidationException {
+        final AtomicReference<Version> version = new AtomicReference<>(Version.parse("11.0.13+8"));
+        final BootstrapCheck check = new BootstrapChecks.JavaVersionCheck() {
+            @Override
+            Version getVersion() {
+                return version.get();
+            }
+        };
+
+        final NodeValidationException e = expectThrows(
+            NodeValidationException.class,
+            () -> BootstrapChecks.check(emptyContext, true, Collections.singletonList(check))
+        );
+        assertThat(
+            e.getMessage(),
+            containsString(
+                "The current JVM version 11.0.13+8 is not recommended for use: "
+                    + "for more details, please check https://github.com/opensearch-project/OpenSearch/issues/2791 and https://bugs.openjdk.java.net/browse/JDK-8259541"
+            )
+        );
+
+        version.set(Version.parse("11.0.14"));
+        BootstrapChecks.check(emptyContext, true, Collections.singletonList(check));
+
+        version.set(Runtime.version());
+        BootstrapChecks.check(emptyContext, true, Collections.singletonList(check));
+    }
+
+    public void testMultipleDataPathsForSearchNodeCheck() {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString(), path.resolve("b").toString() };
+
+        final NodeValidationException e = expectThrows(
+            NodeValidationException.class,
+            () -> performDataPathsCheck(paths, DiscoveryNodeRole.SEARCH_ROLE.roleName())
+        );
+        assertThat(e.getMessage(), containsString("Multiple data paths are not allowed for search nodes"));
+    }
+
+    public void testMultipleDataPathsForDataNodeCheck() throws NodeValidationException {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString(), path.resolve("b").toString() };
+
+        performDataPathsCheck(paths, DiscoveryNodeRole.DATA_ROLE.roleName());
+    }
+
+    public void testSingleDataPathForSearchNodeCheck() throws NodeValidationException {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString() };
+
+        performDataPathsCheck(paths, DiscoveryNodeRole.SEARCH_ROLE.roleName());
+    }
+
+    private void performDataPathsCheck(String[] paths, String roleName) throws NodeValidationException {
+        final BootstrapContext context = createTestContext(
+            Settings.builder()
+                .putList(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), Collections.singletonList(roleName))
+                .putList(Environment.PATH_DATA_SETTING.getKey(), paths)
+                .build(),
+            Metadata.EMPTY_METADATA
+        );
+        final List<BootstrapCheck> checks = Collections.singletonList(new BootstrapChecks.MultipleDataPathCheck());
+        BootstrapChecks.check(context, true, checks);
     }
 }
diff --git a/server/src/test/java/org/opensearch/bootstrap/IdentityPluginTests.java b/server/src/test/java/org/opensearch/bootstrap/IdentityPluginTests.java
new file mode 100644
index 0000000000000..2129810a99879
--- /dev/null
+++ b/server/src/test/java/org/opensearch/bootstrap/IdentityPluginTests.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.bootstrap;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.identity.noop.NoopIdentityPlugin;
+import org.opensearch.identity.noop.NoopTokenManager;
+import org.opensearch.plugins.IdentityPlugin;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+
+public class IdentityPluginTests extends OpenSearchTestCase {
+
+    public void testSingleIdentityPluginSucceeds() {
+        IdentityPlugin identityPlugin1 = new NoopIdentityPlugin();
+        List<IdentityPlugin> pluginList1 = List.of(identityPlugin1);
+        IdentityService identityService1 = new IdentityService(Settings.EMPTY, pluginList1);
+        assertTrue(identityService1.getSubject().getPrincipal().getName().equalsIgnoreCase("Unauthenticated"));
+        assertThat(identityService1.getTokenManager(), is(instanceOf(NoopTokenManager.class)));
+    }
+
+    public void testMultipleIdentityPluginsFail() {
+        IdentityPlugin identityPlugin1 = new NoopIdentityPlugin();
+        IdentityPlugin identityPlugin2 = new NoopIdentityPlugin();
+        IdentityPlugin identityPlugin3 = new NoopIdentityPlugin();
+        List<IdentityPlugin> pluginList = List.of(identityPlugin1, identityPlugin2, identityPlugin3);
+        Exception ex = assertThrows(OpenSearchException.class, () -> new IdentityService(Settings.EMPTY, pluginList));
+        assert (ex.getMessage().contains("Multiple identity plugins are not supported,"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/bootstrap/JavaVersionTests.java b/server/src/test/java/org/opensearch/bootstrap/JavaVersionTests.java
index 24d78e0986342..b651afd253d11 100644
--- a/server/src/test/java/org/opensearch/bootstrap/JavaVersionTests.java
+++ b/server/src/test/java/org/opensearch/bootstrap/JavaVersionTests.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.lang.Runtime.Version;
 import java.util.List;
 
 import static org.hamcrest.CoreMatchers.equalTo;
@@ -41,29 +42,22 @@
 
 public class JavaVersionTests extends OpenSearchTestCase {
     public void testParse() {
-        JavaVersion javaVersion = JavaVersion.parse("1.7.0");
-        List<Integer> version = javaVersion.getVersion();
-        assertThat(version.size(), is(3));
-        assertThat(version.get(0), is(1));
-        assertThat(version.get(1), is(7));
-        assertThat(version.get(2), is(0));
-
-        JavaVersion javaVersionEarlyAccess = JavaVersion.parse("14.0.1-ea");
-        List<Integer> version14 = javaVersionEarlyAccess.getVersion();
+        Version javaVersionEarlyAccess = Version.parse("14.0.1-ea");
+        List<Integer> version14 = javaVersionEarlyAccess.version();
         assertThat(version14.size(), is(3));
         assertThat(version14.get(0), is(14));
         assertThat(version14.get(1), is(0));
         assertThat(version14.get(2), is(1));
 
-        JavaVersion javaVersionOtherPrePart = JavaVersion.parse("13.2.4-somethingElseHere");
-        List<Integer> version13 = javaVersionOtherPrePart.getVersion();
+        Version javaVersionOtherPrePart = Version.parse("13.2.4-somethingElseHere");
+        List<Integer> version13 = javaVersionOtherPrePart.version();
         assertThat(version13.size(), is(3));
         assertThat(version13.get(0), is(13));
         assertThat(version13.get(1), is(2));
         assertThat(version13.get(2), is(4));
 
-        JavaVersion javaVersionNumericPrePart = JavaVersion.parse("13.2.4-something124443");
-        List<Integer> version11 = javaVersionNumericPrePart.getVersion();
+        Version javaVersionNumericPrePart = Version.parse("13.2.4-something124443");
+        List<Integer> version11 = javaVersionNumericPrePart.version();
         assertThat(version11.size(), is(3));
         assertThat(version11.get(0), is(13));
         assertThat(version11.get(1), is(2));
@@ -71,51 +65,36 @@ public void testParse() {
     }
 
     public void testParseInvalidVersions() {
-        final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> JavaVersion.parse("11.2-something-else"));
-        assertThat(e.getMessage(), equalTo("Java version string [11.2-something-else] could not be parsed."));
-        final IllegalArgumentException e1 = expectThrows(IllegalArgumentException.class, () -> JavaVersion.parse("11.0."));
-        assertThat(e1.getMessage(), equalTo("Java version string [11.0.] could not be parsed."));
-        final IllegalArgumentException e2 = expectThrows(IllegalArgumentException.class, () -> JavaVersion.parse("11.a.3"));
-        assertThat(e2.getMessage(), equalTo("Java version string [11.a.3] could not be parsed."));
+        final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Version.parse("11.2+something-else"));
+        assertThat(e.getMessage(), equalTo("Invalid version string: '11.2+something-else'"));
+        final IllegalArgumentException e1 = expectThrows(IllegalArgumentException.class, () -> Version.parse("11.0."));
+        assertThat(e1.getMessage(), equalTo("Invalid version string: '11.0.'"));
+        final IllegalArgumentException e2 = expectThrows(IllegalArgumentException.class, () -> Version.parse("11.a.3"));
+        assertThat(e2.getMessage(), equalTo("Invalid version string: '11.a.3'"));
     }
 
     public void testToString() {
-        JavaVersion javaVersion170 = JavaVersion.parse("1.7.0");
-        assertThat(javaVersion170.toString(), is("1.7.0"));
-        JavaVersion javaVersion9 = JavaVersion.parse("9");
+        Version javaVersion9 = Version.parse("9");
         assertThat(javaVersion9.toString(), is("9"));
-        JavaVersion javaVersion11 = JavaVersion.parse("11.0.1-something09random");
+        Version javaVersion11 = Version.parse("11.0.1-something09random");
         assertThat(javaVersion11.toString(), is("11.0.1-something09random"));
-        JavaVersion javaVersion12 = JavaVersion.parse("12.2-2019");
+        Version javaVersion12 = Version.parse("12.2-2019");
         assertThat(javaVersion12.toString(), is("12.2-2019"));
-        JavaVersion javaVersion13ea = JavaVersion.parse("13.1-ea");
+        Version javaVersion13ea = Version.parse("13.1-ea");
         assertThat(javaVersion13ea.toString(), is("13.1-ea"));
     }
 
     public void testCompare() {
-        JavaVersion onePointSix = JavaVersion.parse("1.6");
-        JavaVersion onePointSeven = JavaVersion.parse("1.7");
-        JavaVersion onePointSevenPointZero = JavaVersion.parse("1.7.0");
-        JavaVersion onePointSevenPointOne = JavaVersion.parse("1.7.1");
-        JavaVersion onePointSevenPointTwo = JavaVersion.parse("1.7.2");
-        JavaVersion onePointSevenPointOnePointOne = JavaVersion.parse("1.7.1.1");
-        JavaVersion onePointSevenPointTwoPointOne = JavaVersion.parse("1.7.2.1");
-        JavaVersion thirteen = JavaVersion.parse("13");
-        JavaVersion thirteenPointTwoPointOne = JavaVersion.parse("13.2.1");
-        JavaVersion thirteenPointTwoPointOneTwoThousand = JavaVersion.parse("13.2.1-2000");
-        JavaVersion thirteenPointTwoPointOneThreeThousand = JavaVersion.parse("13.2.1-3000");
-        JavaVersion thirteenPointTwoPointOneA = JavaVersion.parse("13.2.1-aaa");
-        JavaVersion thirteenPointTwoPointOneB = JavaVersion.parse("13.2.1-bbb");
-        JavaVersion fourteen = JavaVersion.parse("14");
-        JavaVersion fourteenPointTwoPointOne = JavaVersion.parse("14.2.1");
-        JavaVersion fourteenPointTwoPointOneEarlyAccess = JavaVersion.parse("14.2.1-ea");
-
-        assertTrue(onePointSix.compareTo(onePointSeven) < 0);
-        assertTrue(onePointSeven.compareTo(onePointSix) > 0);
-        assertTrue(onePointSix.compareTo(onePointSix) == 0);
-        assertTrue(onePointSeven.compareTo(onePointSevenPointZero) == 0);
-        assertTrue(onePointSevenPointOnePointOne.compareTo(onePointSevenPointOne) > 0);
-        assertTrue(onePointSevenPointTwo.compareTo(onePointSevenPointTwoPointOne) < 0);
+        Version thirteen = Version.parse("13");
+        Version thirteenPointTwoPointOne = Version.parse("13.2.1");
+        Version thirteenPointTwoPointOneTwoThousand = Version.parse("13.2.1-2000");
+        Version thirteenPointTwoPointOneThreeThousand = Version.parse("13.2.1-3000");
+        Version thirteenPointTwoPointOneA = Version.parse("13.2.1-aaa");
+        Version thirteenPointTwoPointOneB = Version.parse("13.2.1-bbb");
+        Version fourteen = Version.parse("14");
+        Version fourteenPointTwoPointOne = Version.parse("14.2.1");
+        Version fourteenPointTwoPointOneEarlyAccess = Version.parse("14.2.1-ea");
+
         assertTrue(thirteen.compareTo(thirteenPointTwoPointOne) < 0);
         assertTrue(thirteen.compareTo(fourteen) < 0);
         assertTrue(thirteenPointTwoPointOneThreeThousand.compareTo(thirteenPointTwoPointOneTwoThousand) > 0);
@@ -129,20 +108,16 @@ public void testCompare() {
     }
 
     public void testValidVersions() {
-        String[] versions = new String[] { "1.7", "1.7.0", "0.1.7", "1.7.0.80", "12-ea", "13.0.2.3-ea", "14-something", "11.0.2-21002" };
+        String[] versions = new String[] { "12-ea", "13.0.2.3-ea", "14-something", "11.0.2-21002", "11.0.14.1+1", "17.0.2+8" };
         for (String version : versions) {
-            assertTrue(JavaVersion.isValid(version));
+            assertNotNull(Version.parse(version));
         }
     }
 
     public void testInvalidVersions() {
-        String[] versions = new String[] { "", "1.7.0_80", "1.7.", "11.2-something-else" };
+        String[] versions = new String[] { "", "1.7.0_80", "1.7.", "11.2+something-else" };
         for (String version : versions) {
-            assertFalse(JavaVersion.isValid(version));
+            assertThrows(IllegalArgumentException.class, () -> Version.parse(version));
         }
     }
-
-    public void testJava8Compat() {
-        assertEquals(JavaVersion.parse("1.8"), JavaVersion.parse("8"));
-    }
 }
diff --git a/server/src/test/java/org/opensearch/bootstrap/MaxMapCountCheckTests.java b/server/src/test/java/org/opensearch/bootstrap/MaxMapCountCheckTests.java
index f1a94096412f7..81a2b1334c39d 100644
--- a/server/src/test/java/org/opensearch/bootstrap/MaxMapCountCheckTests.java
+++ b/server/src/test/java/org/opensearch/bootstrap/MaxMapCountCheckTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.bootstrap;
 
 import org.apache.logging.log4j.Level;
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.util.Constants;
diff --git a/server/src/test/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParserTests.java b/server/src/test/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParserTests.java
new file mode 100644
index 0000000000000..c0507c54be36a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/bootstrap/jvm/DenyJvmVersionsParserTests.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.bootstrap.jvm;
+
+import org.opensearch.bootstrap.jvm.DenyJvmVersionsParser.VersionPredicate;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.lang.Runtime.Version;
+import java.util.Collection;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.collection.IsEmptyCollection.empty;
+
+public class DenyJvmVersionsParserTests extends OpenSearchTestCase {
+    public void testDefaults() {
+        final Collection<VersionPredicate> versions = DenyJvmVersionsParser.getDeniedJvmVersions();
+        assertThat(versions, not(empty()));
+    }
+
+    public void testSingleVersion() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("11.0.2: know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(false));
+        assertThat(predicate.test(Version.parse("11.0.3")), is(false));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testVersionRangeLowerIncluded() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("[11.0.2, 11.0.14): know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(false));
+        assertThat(predicate.test(Version.parse("11.0.13+1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14")), is(false));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testVersionRangeUpperIncluded() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("[11.0.2,): know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(false));
+        assertThat(predicate.test(Version.parse("11.0.13+1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14")), is(true));
+        assertThat(predicate.test(Version.parse("17.2.1")), is(true));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testVersionRangeLowerAndUpperIncluded() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("[11.0.2, 11.0.14]: know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(false));
+        assertThat(predicate.test(Version.parse("11.0.13+1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14.1")), is(false));
+        assertThat(predicate.test(Version.parse("11.0.15")), is(false));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testAllVersionsRange() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("(,): know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.13+1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14.1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.15")), is(true));
+        assertThat(predicate.test(Version.parse("17.2.1")), is(true));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testAllVersionsRangeIncluded() {
+        final VersionPredicate predicate = DenyJvmVersionsParser.parse("[*, *]: know to be flawed version");
+        assertThat(predicate.test(Version.parse("11.0.2")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.13+1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.14.1")), is(true));
+        assertThat(predicate.test(Version.parse("11.0.15")), is(true));
+        assertThat(predicate.test(Version.parse("17.2.1")), is(true));
+        assertThat(predicate.getReason(), equalTo("know to be flawed version"));
+    }
+
+    public void testIncorrectVersionRanges() {
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("[*, *: know to be flawed version"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("*, *: know to be flawed version"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("*, *): know to be flawed version"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("(): know to be flawed version"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("[]: know to be flawed version"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("[,]"));
+        assertThrows(IllegalArgumentException.class, () -> DenyJvmVersionsParser.parse("11.0.2"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/client/AbstractClientHeadersTestCase.java b/server/src/test/java/org/opensearch/client/AbstractClientHeadersTestCase.java
index 92a88aa7940ee..682ea395b0193 100644
--- a/server/src/test/java/org/opensearch/client/AbstractClientHeadersTestCase.java
+++ b/server/src/test/java/org/opensearch/client/AbstractClientHeadersTestCase.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteAction;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotAction;
 import org.opensearch.action.admin.cluster.stats.ClusterStatsAction;
@@ -49,7 +48,8 @@
 import org.opensearch.action.search.SearchAction;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
@@ -130,7 +130,7 @@ public void testActions() {
             .execute(new AssertingActionListener<>(DeleteStoredScriptAction.NAME, client.threadPool()));
         client.prepareIndex("idx")
             .setId("id")
-            .setSource("source", XContentType.JSON)
+            .setSource("source", MediaTypeRegistry.JSON)
             .execute(new AssertingActionListener<>(IndexAction.NAME, client.threadPool()));
 
         // choosing arbitrary cluster admin actions to test
diff --git a/server/src/test/java/org/opensearch/client/OriginSettingClientTests.java b/server/src/test/java/org/opensearch/client/OriginSettingClientTests.java
index 2f24ff3fb1f29..3449d2d5ea51d 100644
--- a/server/src/test/java/org/opensearch/client/OriginSettingClientTests.java
+++ b/server/src/test/java/org/opensearch/client/OriginSettingClientTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 
@@ -77,9 +77,8 @@ protected <Request extends ActionRequest, Response extends ActionResponse> void
     }
 
     private <T> ActionListener<T> listenerThatAssertsOriginNotSet(ThreadContext threadContext) {
-        return ActionListener.wrap(
-            r -> { assertNull(threadContext.getTransient(ThreadContext.ACTION_ORIGIN_TRANSIENT_NAME)); },
-            e -> { fail("didn't expect to fail but: " + e); }
-        );
+        return ActionListener.wrap(r -> { assertNull(threadContext.getTransient(ThreadContext.ACTION_ORIGIN_TRANSIENT_NAME)); }, e -> {
+            fail("didn't expect to fail but: " + e);
+        });
     }
 }
diff --git a/server/src/test/java/org/opensearch/client/ParentTaskAssigningClientTests.java b/server/src/test/java/org/opensearch/client/ParentTaskAssigningClientTests.java
index 93cd89ce31a08..ce956273ed3ae 100644
--- a/server/src/test/java/org/opensearch/client/ParentTaskAssigningClientTests.java
+++ b/server/src/test/java/org/opensearch/client/ParentTaskAssigningClientTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.client;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 
diff --git a/server/src/test/java/org/opensearch/client/node/NodeClientHeadersTests.java b/server/src/test/java/org/opensearch/client/node/NodeClientHeadersTests.java
index cb9e3a6a19388..176c94b01c878 100644
--- a/server/src/test/java/org/opensearch/client/node/NodeClientHeadersTests.java
+++ b/server/src/test/java/org/opensearch/client/node/NodeClientHeadersTests.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.client.node;
 
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.client.AbstractClientHeadersTestCase;
 import org.opensearch.client.Client;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.threadpool.ThreadPool;
@@ -57,14 +58,16 @@ protected Client buildClient(Settings headersSettings, ActionType[] testedAction
         Settings settings = HEADER_SETTINGS;
         Actions actions = new Actions(settings, threadPool, testedActions);
         NodeClient client = new NodeClient(settings, threadPool);
-        client.initialize(actions, () -> "test", null, new NamedWriteableRegistry(Collections.emptyList()));
+        DynamicActionRegistry dynamicActionRegistry = new DynamicActionRegistry();
+        dynamicActionRegistry.registerUnmodifiableActionMap(actions);
+        client.initialize(dynamicActionRegistry, () -> "test", null, new NamedWriteableRegistry(Collections.emptyList()));
         return client;
     }
 
     private static class Actions extends HashMap<ActionType, TransportAction> {
 
-        private Actions(Settings settings, ThreadPool threadPool, ActionType[] actions) {
-            for (ActionType action : actions) {
+        private Actions(Settings settings, ThreadPool threadPool, ActionType<?>[] actions) {
+            for (ActionType<?> action : actions) {
                 put(action, new InternalTransportAction(settings, action.name(), threadPool));
             }
         }
diff --git a/server/src/test/java/org/opensearch/cluster/ClusterChangedEventTests.java b/server/src/test/java/org/opensearch/cluster/ClusterChangedEventTests.java
index 49d4a8baf0a1c..963e25f29b399 100644
--- a/server/src/test/java/org/opensearch/cluster/ClusterChangedEventTests.java
+++ b/server/src/test/java/org/opensearch/cluster/ClusterChangedEventTests.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import org.opensearch.Version;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.metadata.IndexGraveyard;
@@ -45,8 +43,8 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.gateway.GatewayService;
-import org.opensearch.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.TestCustomMetadata;
 
@@ -57,6 +55,7 @@
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -107,19 +106,19 @@ public void testBasicProperties() {
     }
 
     /**
-     * Test whether the ClusterChangedEvent returns the correct value for whether the local node is master,
+     * Test whether the ClusterChangedEvent returns the correct value for whether the local node is cluster-manager,
      * based on what was set on the cluster state.
      */
-    public void testLocalNodeIsMaster() {
+    public void testLocalNodeIsClusterManager() {
         final int numNodesInCluster = 3;
         ClusterState previousState = createSimpleClusterState();
         ClusterState newState = createState(numNodesInCluster, true, initialIndices);
         ClusterChangedEvent event = new ClusterChangedEvent("_na_", newState, previousState);
-        assertTrue("local node should be master", event.localNodeMaster());
+        assertTrue("local node should be cluster-manager", event.localNodeClusterManager());
 
         newState = createState(numNodesInCluster, false, initialIndices);
         event = new ClusterChangedEvent("_na_", newState, previousState);
-        assertFalse("local node should not be master", event.localNodeMaster());
+        assertFalse("local node should not be cluster-manager", event.localNodeClusterManager());
     }
 
     /**
@@ -314,6 +313,35 @@ public void testChangedCustomMetadataSet() {
         assertTrue(changedCustomMetadataTypeSet.contains(customMetadata1.getWriteableName()));
     }
 
+    // Validate the above test case testLocalNodeIsClusterManager() passes when the deprecated 'master' role is assigned to the local node.
+    public void testLocalNodeIsClusterManagerWithDeprecatedMasterRole() {
+        final DiscoveryNodes.Builder builderLocalIsMaster = DiscoveryNodes.builder();
+        final DiscoveryNode node0 = newNode("node_0", Set.of(DiscoveryNodeRole.MASTER_ROLE));
+        final DiscoveryNode node1 = newNode("node_1", Set.of(DiscoveryNodeRole.DATA_ROLE));
+        builderLocalIsMaster.add(node0).add(node1).clusterManagerNodeId(node0.getId()).localNodeId(node0.getId());
+
+        final DiscoveryNodes.Builder builderLocalNotMaster = DiscoveryNodes.builder();
+        builderLocalNotMaster.add(node0).add(node1).clusterManagerNodeId(node0.getId()).localNodeId(node1.getId());
+
+        ClusterState previousState = createSimpleClusterState();
+        final Metadata metadata = createMetadata(initialIndices);
+        ClusterState newState = ClusterState.builder(TEST_CLUSTER_NAME)
+            .nodes(builderLocalIsMaster.build())
+            .metadata(metadata)
+            .routingTable(createRoutingTable(1, metadata))
+            .build();
+        ClusterChangedEvent event = new ClusterChangedEvent("_na_", newState, previousState);
+        assertTrue("local node should be master", event.localNodeClusterManager());
+
+        newState = ClusterState.builder(TEST_CLUSTER_NAME)
+            .nodes(builderLocalNotMaster.build())
+            .metadata(metadata)
+            .routingTable(createRoutingTable(1, metadata))
+            .build();
+        event = new ClusterChangedEvent("_na_", newState, previousState);
+        assertFalse("local node should not be master", event.localNodeClusterManager());
+    }
+
     private static class CustomMetadata2 extends TestCustomMetadata {
         protected CustomMetadata2(String data) {
             super(data);
@@ -361,18 +389,18 @@ private static ClusterState createSimpleClusterState() {
     }
 
     // Create a basic cluster state with a given set of indices
-    private static ClusterState createState(final int numNodes, final boolean isLocalMaster, final List<Index> indices) {
+    private static ClusterState createState(final int numNodes, final boolean isLocalClusterManager, final List<Index> indices) {
         final Metadata metadata = createMetadata(indices);
         return ClusterState.builder(TEST_CLUSTER_NAME)
-            .nodes(createDiscoveryNodes(numNodes, isLocalMaster))
+            .nodes(createDiscoveryNodes(numNodes, isLocalClusterManager))
             .metadata(metadata)
             .routingTable(createRoutingTable(1, metadata))
             .build();
     }
 
     // Create a non-initialized cluster state
-    private static ClusterState createNonInitializedState(final int numNodes, final boolean isLocalMaster) {
-        final ClusterState withoutBlock = createState(numNodes, isLocalMaster, Collections.emptyList());
+    private static ClusterState createNonInitializedState(final int numNodes, final boolean isLocalClusterManager) {
+        final ClusterState withoutBlock = createState(numNodes, isLocalClusterManager, Collections.emptyList());
         return ClusterState.builder(withoutBlock)
             .blocks(ClusterBlocks.builder().addGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK).build())
             .build();
@@ -382,9 +410,9 @@ private static ClusterState nextState(final ClusterState previousState, List<Tes
         final ClusterState.Builder builder = ClusterState.builder(previousState);
         builder.stateUUID(UUIDs.randomBase64UUID());
         Metadata.Builder metadataBuilder = new Metadata.Builder(previousState.metadata());
-        for (ObjectObjectCursor<String, Metadata.Custom> customMetadata : previousState.metadata().customs()) {
-            if (customMetadata.value instanceof TestCustomMetadata) {
-                metadataBuilder.removeCustom(customMetadata.key);
+        for (Map.Entry<String, Metadata.Custom> customMetadata : previousState.metadata().customs().entrySet()) {
+            if (customMetadata.getValue() instanceof TestCustomMetadata) {
+                metadataBuilder.removeCustom(customMetadata.getKey());
             }
         }
         for (TestCustomMetadata testCustomMetadata : customMetadataList) {
@@ -434,28 +462,29 @@ private static ClusterState nextState(
     }
 
     // Create the discovery nodes for a cluster state. For our testing purposes, we want
-    // the first to be master, the second to be master eligible, the third to be a data node,
-    // and the remainder can be any kinds of nodes (master eligible, data, or both).
-    private static DiscoveryNodes createDiscoveryNodes(final int numNodes, final boolean isLocalMaster) {
+    // the first to be cluster-manager, the second to be cluster-manager eligible, the third to be a data node,
+    // and the remainder can be any kinds of nodes (cluster-manager eligible, data, or both).
+    private static DiscoveryNodes createDiscoveryNodes(final int numNodes, final boolean isLocalClusterManager) {
         assert (numNodes >= 3) : "the initial cluster state for event change tests should have a minimum of 3 nodes "
-            + "so there are a minimum of 2 master nodes for testing master change events.";
+            + "so there are a minimum of 2 cluster-manager nodes for testing cluster-manager change events.";
         final DiscoveryNodes.Builder builder = DiscoveryNodes.builder();
-        final int localNodeIndex = isLocalMaster ? 0 : randomIntBetween(1, numNodes - 1); // randomly assign the local node if not master
+        final int localNodeIndex = isLocalClusterManager ? 0 : randomIntBetween(1, numNodes - 1); // randomly assign the local node if not
+                                                                                                  // cluster-manager
         for (int i = 0; i < numNodes; i++) {
             final String nodeId = NODE_ID_PREFIX + i;
             Set<DiscoveryNodeRole> roles = new HashSet<>();
             if (i == 0) {
-                // the master node
-                builder.masterNodeId(nodeId);
+                // the cluster-manager node
+                builder.clusterManagerNodeId(nodeId);
                 roles.add(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
             } else if (i == 1) {
-                // the alternate master node
+                // the alternate cluster-manager node
                 roles.add(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
             } else if (i == 2) {
                 // we need at least one data node
                 roles.add(DiscoveryNodeRole.DATA_ROLE);
             } else {
-                // remaining nodes can be anything (except for master)
+                // remaining nodes can be anything (except for cluster-manager)
                 if (randomBoolean()) {
                     roles.add(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
                 }
@@ -520,8 +549,8 @@ private static IndexMetadata createIndexMetadata(final Index index, final long v
     // Create the routing table for a cluster state.
     private static RoutingTable createRoutingTable(final long version, final Metadata metadata) {
         final RoutingTable.Builder builder = RoutingTable.builder().version(version);
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            builder.addAsNew(cursor.value);
+        for (final IndexMetadata cursor : metadata.indices().values()) {
+            builder.addAsNew(cursor);
         }
         return builder.build();
     }
@@ -552,7 +581,7 @@ private static ClusterState executeIndicesChangesTest(
     ) {
         final int numAdd = randomIntBetween(0, 5); // add random # of indices to the next cluster state
         final List<Index> stateIndices = new ArrayList<>();
-        for (Iterator<IndexMetadata> iter = previousState.metadata().indices().valuesIt(); iter.hasNext();) {
+        for (Iterator<IndexMetadata> iter = previousState.metadata().indices().values().iterator(); iter.hasNext();) {
             stateIndices.add(iter.next().getIndex());
         }
         final int numDel;
diff --git a/server/src/test/java/org/opensearch/cluster/ClusterInfoTests.java b/server/src/test/java/org/opensearch/cluster/ClusterInfoTests.java
index 4abbef0c19374..4ec7db2f3d552 100644
--- a/server/src/test/java/org/opensearch/cluster/ClusterInfoTests.java
+++ b/server/src/test/java/org/opensearch/cluster/ClusterInfoTests.java
@@ -34,11 +34,14 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class ClusterInfoTests extends OpenSearchTestCase {
 
     public void testSerialization() throws Exception {
@@ -47,7 +50,8 @@ public void testSerialization() throws Exception {
             randomDiskUsage(),
             randomShardSizes(),
             randomRoutingToDataPath(),
-            randomReservedSpace()
+            randomReservedSpace(),
+            randomFileCacheStats()
         );
         BytesStreamOutput output = new BytesStreamOutput();
         clusterInfo.writeTo(output);
@@ -58,11 +62,12 @@ public void testSerialization() throws Exception {
         assertEquals(clusterInfo.shardSizes, result.shardSizes);
         assertEquals(clusterInfo.routingToDataPath, result.routingToDataPath);
         assertEquals(clusterInfo.reservedSpace, result.reservedSpace);
+        assertEquals(clusterInfo.getNodeFileCacheStats().size(), result.getNodeFileCacheStats().size());
     }
 
-    private static ImmutableOpenMap<String, DiskUsage> randomDiskUsage() {
+    private static Map<String, DiskUsage> randomDiskUsage() {
         int numEntries = randomIntBetween(0, 128);
-        ImmutableOpenMap.Builder<String, DiskUsage> builder = ImmutableOpenMap.builder(numEntries);
+        final Map<String, DiskUsage> builder = new HashMap<>(numEntries);
         for (int i = 0; i < numEntries; i++) {
             String key = randomAlphaOfLength(32);
             DiskUsage diskUsage = new DiskUsage(
@@ -74,34 +79,53 @@ private static ImmutableOpenMap<String, DiskUsage> randomDiskUsage() {
             );
             builder.put(key, diskUsage);
         }
-        return builder.build();
+        return builder;
+    }
+
+    private static Map<String, FileCacheStats> randomFileCacheStats() {
+        int numEntries = randomIntBetween(0, 16);
+        final Map<String, FileCacheStats> builder = new HashMap<>(numEntries);
+        for (int i = 0; i < numEntries; i++) {
+            String key = randomAlphaOfLength(16);
+            FileCacheStats fileCacheStats = new FileCacheStats(
+                randomLong(),
+                randomLong(),
+                randomLong(),
+                randomLong(),
+                randomLong(),
+                randomLong(),
+                randomLong()
+            );
+            builder.put(key, fileCacheStats);
+        }
+        return builder;
     }
 
-    private static ImmutableOpenMap<String, Long> randomShardSizes() {
+    private static Map<String, Long> randomShardSizes() {
         int numEntries = randomIntBetween(0, 128);
-        ImmutableOpenMap.Builder<String, Long> builder = ImmutableOpenMap.builder(numEntries);
+        final Map<String, Long> builder = new HashMap<>(numEntries);
         for (int i = 0; i < numEntries; i++) {
             String key = randomAlphaOfLength(32);
             long shardSize = randomIntBetween(0, Integer.MAX_VALUE);
             builder.put(key, shardSize);
         }
-        return builder.build();
+        return builder;
     }
 
-    private static ImmutableOpenMap<ShardRouting, String> randomRoutingToDataPath() {
+    private static Map<ShardRouting, String> randomRoutingToDataPath() {
         int numEntries = randomIntBetween(0, 128);
-        ImmutableOpenMap.Builder<ShardRouting, String> builder = ImmutableOpenMap.builder(numEntries);
+        final Map<ShardRouting, String> builder = new HashMap<>(numEntries);
         for (int i = 0; i < numEntries; i++) {
             ShardId shardId = new ShardId(randomAlphaOfLength(32), randomAlphaOfLength(32), randomIntBetween(0, Integer.MAX_VALUE));
             ShardRouting shardRouting = TestShardRouting.newShardRouting(shardId, null, randomBoolean(), ShardRoutingState.UNASSIGNED);
             builder.put(shardRouting, randomAlphaOfLength(32));
         }
-        return builder.build();
+        return builder;
     }
 
-    private static ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> randomReservedSpace() {
+    private static Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> randomReservedSpace() {
         int numEntries = randomIntBetween(0, 128);
-        ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> builder = ImmutableOpenMap.builder(numEntries);
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> builder = new HashMap<>(numEntries);
         for (int i = 0; i < numEntries; i++) {
             final ClusterInfo.NodeAndPath key = new ClusterInfo.NodeAndPath(randomAlphaOfLength(10), randomAlphaOfLength(10));
             final ClusterInfo.ReservedSpace.Builder valueBuilder = new ClusterInfo.ReservedSpace.Builder();
@@ -111,7 +135,7 @@ private static ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpa
             }
             builder.put(key, valueBuilder.build());
         }
-        return builder.build();
+        return builder;
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/cluster/ClusterModuleTests.java b/server/src/test/java/org/opensearch/cluster/ClusterModuleTests.java
index 004b784311b54..535444cd866b8 100644
--- a/server/src/test/java/org/opensearch/cluster/ClusterModuleTests.java
+++ b/server/src/test/java/org/opensearch/cluster/ClusterModuleTests.java
@@ -57,6 +57,7 @@
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.SnapshotInProgressAllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.TargetPoolAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.ModuleTestCase;
@@ -238,7 +239,8 @@ public void testAllocationDeciderOrder() {
             ThrottlingAllocationDecider.class,
             ShardsLimitAllocationDecider.class,
             AwarenessAllocationDecider.class,
-            NodeLoadAwareAllocationDecider.class
+            NodeLoadAwareAllocationDecider.class,
+            TargetPoolAllocationDecider.class
         );
         Collection<AllocationDecider> deciders = ClusterModule.createAllocationDeciders(
             Settings.EMPTY,
diff --git a/server/src/test/java/org/opensearch/cluster/ClusterStateTests.java b/server/src/test/java/org/opensearch/cluster/ClusterStateTests.java
index 7cbab104cd07a..457bdac1809ef 100644
--- a/server/src/test/java/org/opensearch/cluster/ClusterStateTests.java
+++ b/server/src/test/java/org/opensearch/cluster/ClusterStateTests.java
@@ -49,16 +49,14 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.TestCustomMetadata;
 
@@ -66,6 +64,7 @@
 import java.net.InetAddress;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -74,6 +73,7 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -85,32 +85,35 @@ public void testSupersedes() {
         final DiscoveryNode node1 = new DiscoveryNode("node1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), version);
         final DiscoveryNode node2 = new DiscoveryNode("node2", buildNewFakeTransportAddress(), emptyMap(), emptySet(), version);
         final DiscoveryNodes nodes = DiscoveryNodes.builder().add(node1).add(node2).build();
-        ClusterName name = ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY);
-        ClusterState noMaster1 = ClusterState.builder(name).version(randomInt(5)).nodes(nodes).build();
-        ClusterState noMaster2 = ClusterState.builder(name).version(randomInt(5)).nodes(nodes).build();
-        ClusterState withMaster1a = ClusterState.builder(name)
+        ClusterName name = CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY);
+        ClusterState noClusterManager1 = ClusterState.builder(name).version(randomInt(5)).nodes(nodes).build();
+        ClusterState noClusterManager2 = ClusterState.builder(name).version(randomInt(5)).nodes(nodes).build();
+        ClusterState withClusterManager1a = ClusterState.builder(name)
             .version(randomInt(5))
-            .nodes(DiscoveryNodes.builder(nodes).masterNodeId(node1.getId()))
+            .nodes(DiscoveryNodes.builder(nodes).clusterManagerNodeId(node1.getId()))
             .build();
-        ClusterState withMaster1b = ClusterState.builder(name)
+        ClusterState withClusterManager1b = ClusterState.builder(name)
             .version(randomInt(5))
-            .nodes(DiscoveryNodes.builder(nodes).masterNodeId(node1.getId()))
+            .nodes(DiscoveryNodes.builder(nodes).clusterManagerNodeId(node1.getId()))
             .build();
-        ClusterState withMaster2 = ClusterState.builder(name)
+        ClusterState withClusterManager2 = ClusterState.builder(name)
             .version(randomInt(5))
-            .nodes(DiscoveryNodes.builder(nodes).masterNodeId(node2.getId()))
+            .nodes(DiscoveryNodes.builder(nodes).clusterManagerNodeId(node2.getId()))
             .build();
 
-        // states with no master should never supersede anything
-        assertFalse(noMaster1.supersedes(noMaster2));
-        assertFalse(noMaster1.supersedes(withMaster1a));
+        // states with no cluster-manager should never supersede anything
+        assertFalse(noClusterManager1.supersedes(noClusterManager2));
+        assertFalse(noClusterManager1.supersedes(withClusterManager1a));
 
-        // states should never supersede states from another master
-        assertFalse(withMaster1a.supersedes(withMaster2));
-        assertFalse(withMaster1a.supersedes(noMaster1));
+        // states should never supersede states from another cluster-manager
+        assertFalse(withClusterManager1a.supersedes(withClusterManager2));
+        assertFalse(withClusterManager1a.supersedes(noClusterManager1));
 
-        // state from the same master compare by version
-        assertThat(withMaster1a.supersedes(withMaster1b), equalTo(withMaster1a.version() > withMaster1b.version()));
+        // state from the same cluster-manager compare by version
+        assertThat(
+            withClusterManager1a.supersedes(withClusterManager1b),
+            equalTo(withClusterManager1a.version() > withClusterManager1b.version())
+        );
     }
 
     public void testBuilderRejectsNullCustom() {
@@ -122,9 +125,9 @@ public void testBuilderRejectsNullCustom() {
     public void testBuilderRejectsNullInCustoms() {
         final ClusterState.Builder builder = ClusterState.builder(ClusterName.DEFAULT);
         final String key = randomAlphaOfLength(10);
-        final ImmutableOpenMap.Builder<String, ClusterState.Custom> mapBuilder = ImmutableOpenMap.builder();
+        final Map<String, ClusterState.Custom> mapBuilder = new HashMap<>();
         mapBuilder.put(key, null);
-        final ImmutableOpenMap<String, ClusterState.Custom> map = mapBuilder.build();
+        final Map<String, ClusterState.Custom> map = Collections.unmodifiableMap(mapBuilder);
         assertThat(expectThrows(NullPointerException.class, () -> builder.customs(map)).getMessage(), containsString(key));
     }
 
@@ -146,8 +149,8 @@ public void testToXContent() throws IOException {
                 + "  \"cluster_uuid\" : \"clusterUUID\",\n"
                 + "  \"version\" : 0,\n"
                 + "  \"state_uuid\" : \"stateUUID\",\n"
-                + "  \"master_node\" : \"masterNodeId\",\n"
-                + "  \"cluster_manager_node\" : \"masterNodeId\",\n"
+                + "  \"master_node\" : \"clusterManagerNodeId\",\n"
+                + "  \"cluster_manager_node\" : \"clusterManagerNodeId\",\n"
                 + "  \"blocks\" : {\n"
                 + "    \"global\" : {\n"
                 + "      \"1\" : {\n"
@@ -158,7 +161,8 @@ public void testToXContent() throws IOException {
                 + "          \"read\",\n"
                 + "          \"write\",\n"
                 + "          \"metadata_read\",\n"
-                + "          \"metadata_write\"\n"
+                + "          \"metadata_write\",\n"
+                + "          \"create_index\"\n"
                 + "        ]\n"
                 + "      }\n"
                 + "    },\n"
@@ -171,7 +175,8 @@ public void testToXContent() throws IOException {
                 + "            \"read\",\n"
                 + "            \"write\",\n"
                 + "            \"metadata_read\",\n"
-                + "            \"metadata_write\"\n"
+                + "            \"metadata_write\",\n"
+                + "            \"create_index\"\n"
                 + "          ]\n"
                 + "        }\n"
                 + "      }\n"
@@ -322,7 +327,7 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
     }
@@ -352,8 +357,8 @@ public void testToXContent_FlatSettingTrue_ReduceMappingFalse() throws IOExcepti
                 + "  \"cluster_uuid\" : \"clusterUUID\",\n"
                 + "  \"version\" : 0,\n"
                 + "  \"state_uuid\" : \"stateUUID\",\n"
-                + "  \"master_node\" : \"masterNodeId\",\n"
-                + "  \"cluster_manager_node\" : \"masterNodeId\",\n"
+                + "  \"master_node\" : \"clusterManagerNodeId\",\n"
+                + "  \"cluster_manager_node\" : \"clusterManagerNodeId\",\n"
                 + "  \"blocks\" : {\n"
                 + "    \"global\" : {\n"
                 + "      \"1\" : {\n"
@@ -364,7 +369,8 @@ public void testToXContent_FlatSettingTrue_ReduceMappingFalse() throws IOExcepti
                 + "          \"read\",\n"
                 + "          \"write\",\n"
                 + "          \"metadata_read\",\n"
-                + "          \"metadata_write\"\n"
+                + "          \"metadata_write\",\n"
+                + "          \"create_index\"\n"
                 + "        ]\n"
                 + "      }\n"
                 + "    },\n"
@@ -377,7 +383,8 @@ public void testToXContent_FlatSettingTrue_ReduceMappingFalse() throws IOExcepti
                 + "            \"read\",\n"
                 + "            \"write\",\n"
                 + "            \"metadata_read\",\n"
-                + "            \"metadata_write\"\n"
+                + "            \"metadata_write\",\n"
+                + "            \"create_index\"\n"
                 + "          ]\n"
                 + "        }\n"
                 + "      }\n"
@@ -520,7 +527,7 @@ public void testToXContent_FlatSettingTrue_ReduceMappingFalse() throws IOExcepti
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
     }
@@ -551,8 +558,8 @@ public void testToXContent_FlatSettingFalse_ReduceMappingTrue() throws IOExcepti
                 + "  \"cluster_uuid\" : \"clusterUUID\",\n"
                 + "  \"version\" : 0,\n"
                 + "  \"state_uuid\" : \"stateUUID\",\n"
-                + "  \"master_node\" : \"masterNodeId\",\n"
-                + "  \"cluster_manager_node\" : \"masterNodeId\",\n"
+                + "  \"master_node\" : \"clusterManagerNodeId\",\n"
+                + "  \"cluster_manager_node\" : \"clusterManagerNodeId\",\n"
                 + "  \"blocks\" : {\n"
                 + "    \"global\" : {\n"
                 + "      \"1\" : {\n"
@@ -563,7 +570,8 @@ public void testToXContent_FlatSettingFalse_ReduceMappingTrue() throws IOExcepti
                 + "          \"read\",\n"
                 + "          \"write\",\n"
                 + "          \"metadata_read\",\n"
-                + "          \"metadata_write\"\n"
+                + "          \"metadata_write\",\n"
+                + "          \"create_index\"\n"
                 + "        ]\n"
                 + "      }\n"
                 + "    },\n"
@@ -576,7 +584,8 @@ public void testToXContent_FlatSettingFalse_ReduceMappingTrue() throws IOExcepti
                 + "            \"read\",\n"
                 + "            \"write\",\n"
                 + "            \"metadata_read\",\n"
-                + "            \"metadata_write\"\n"
+                + "            \"metadata_write\",\n"
+                + "            \"create_index\"\n"
                 + "          ]\n"
                 + "        }\n"
                 + "      }\n"
@@ -725,7 +734,7 @@ public void testToXContent_FlatSettingFalse_ReduceMappingTrue() throws IOExcepti
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
     }
@@ -835,7 +844,7 @@ public void testToXContentSameTypeName() throws IOException {
                 + "    \"nodes\" : { }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -868,7 +877,7 @@ private ClusterState buildClusterState() throws IOException {
             .stateUUID("stateUUID")
             .nodes(
                 DiscoveryNodes.builder()
-                    .masterNodeId("masterNodeId")
+                    .clusterManagerNodeId("clusterManagerNodeId")
                     .add(new DiscoveryNode("nodeId1", new TransportAddress(InetAddress.getByName("127.0.0.1"), 111), Version.CURRENT))
                     .build()
             )
diff --git a/server/src/test/java/org/opensearch/cluster/DiskUsageTests.java b/server/src/test/java/org/opensearch/cluster/DiskUsageTests.java
index 8259971d1b695..8ba965b3df1ab 100644
--- a/server/src/test/java/org/opensearch/cluster/DiskUsageTests.java
+++ b/server/src/test/java/org/opensearch/cluster/DiskUsageTests.java
@@ -41,9 +41,8 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingHelper;
 import org.opensearch.cluster.routing.UnassignedInfo;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.StoreStats;
 import org.opensearch.monitor.fs.FsInfo;
@@ -53,6 +52,7 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
@@ -137,9 +137,8 @@ public void testFillShardLevelInfo() {
         ShardStats[] stats = new ShardStats[] {
             new ShardStats(test_0, new ShardPath(false, test0Path, test0Path, test_0.shardId()), commonStats0, null, null, null),
             new ShardStats(test_1, new ShardPath(false, test1Path, test1Path, test_1.shardId()), commonStats1, null, null, null) };
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<ShardRouting, String> routingToPath = ImmutableOpenMap.builder();
-        ClusterState state = ClusterState.builder(new ClusterName("blarg")).version(0).build();
+        final Map<String, Long> shardSizes = new HashMap<>();
+        final Map<ShardRouting, String> routingToPath = new HashMap<>();
         InternalClusterInfoService.buildShardLevelInfo(logger, stats, shardSizes, routingToPath, new HashMap<>());
         assertEquals(2, shardSizes.size());
         assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(test_0)));
@@ -155,8 +154,8 @@ public void testFillShardLevelInfo() {
     }
 
     public void testFillDiskUsage() {
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvaiableUsages = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvaiableUsages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> newLeastAvaiableUsages = new HashMap<>();
+        final Map<String, DiskUsage> newMostAvaiableUsages = new HashMap<>();
         FsInfo.Path[] node1FSInfo = new FsInfo.Path[] {
             new FsInfo.Path("/middle", "/dev/sda", 100, 90, 80),
             new FsInfo.Path("/least", "/dev/sdb", 200, 190, 70),
@@ -185,6 +184,12 @@ public void testFillDiskUsage() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             ),
             new NodeStats(
@@ -205,6 +210,12 @@ public void testFillDiskUsage() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             ),
             new NodeStats(
@@ -225,6 +236,12 @@ public void testFillDiskUsage() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             )
         );
@@ -246,8 +263,8 @@ public void testFillDiskUsage() {
     }
 
     public void testFillDiskUsageSomeInvalidValues() {
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvailableUsages = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvailableUsages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> newLeastAvailableUsages = new HashMap<>();
+        final Map<String, DiskUsage> newMostAvailableUsages = new HashMap<>();
         FsInfo.Path[] node1FSInfo = new FsInfo.Path[] {
             new FsInfo.Path("/middle", "/dev/sda", 100, 90, 80),
             new FsInfo.Path("/least", "/dev/sdb", -1, -1, -1),
@@ -276,6 +293,12 @@ public void testFillDiskUsageSomeInvalidValues() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             ),
             new NodeStats(
@@ -296,6 +319,12 @@ public void testFillDiskUsageSomeInvalidValues() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             ),
             new NodeStats(
@@ -316,6 +345,12 @@ public void testFillDiskUsageSomeInvalidValues() {
                 null,
                 null,
                 null,
+                null,
+                null,
+                null,
+                null,
+                null,
+                null,
                 null
             )
         );
diff --git a/server/src/test/java/org/opensearch/cluster/FeatureAwareTests.java b/server/src/test/java/org/opensearch/cluster/FeatureAwareTests.java
index 0191492dcf9d3..da0f81d9b8a5b 100644
--- a/server/src/test/java/org/opensearch/cluster/FeatureAwareTests.java
+++ b/server/src/test/java/org/opensearch/cluster/FeatureAwareTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.cluster.ClusterState.FeatureAware;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/cluster/InternalClusterInfoServiceSchedulingTests.java b/server/src/test/java/org/opensearch/cluster/InternalClusterInfoServiceSchedulingTests.java
index c6279d0029009..47dbf85c13b1f 100644
--- a/server/src/test/java/org/opensearch/cluster/InternalClusterInfoServiceSchedulingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/InternalClusterInfoServiceSchedulingTests.java
@@ -33,32 +33,33 @@
 package org.opensearch.cluster;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest;
 import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.coordination.MockSinglePrioritizingExecutor;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterApplier;
 import org.opensearch.cluster.service.ClusterApplierService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.cluster.service.FakeThreadPoolMasterService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.FakeThreadPoolClusterManagerService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.node.Node;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpClient;
 import org.opensearch.threadpool.ThreadPool;
 
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.opensearch.cluster.InternalClusterInfoService.INTERNAL_CLUSTER_INFO_UPDATE_INTERVAL_SETTING;
@@ -68,8 +69,10 @@ public class InternalClusterInfoServiceSchedulingTests extends OpenSearchTestCas
 
     public void testScheduling() {
         final DiscoveryNode discoveryNode = new DiscoveryNode("test", buildNewFakeTransportAddress(), Version.CURRENT);
-        final DiscoveryNodes noMaster = DiscoveryNodes.builder().add(discoveryNode).localNodeId(discoveryNode.getId()).build();
-        final DiscoveryNodes localMaster = DiscoveryNodes.builder(noMaster).masterNodeId(discoveryNode.getId()).build();
+        final DiscoveryNodes noClusterManager = DiscoveryNodes.builder().add(discoveryNode).localNodeId(discoveryNode.getId()).build();
+        final DiscoveryNodes localClusterManager = DiscoveryNodes.builder(noClusterManager)
+            .clusterManagerNodeId(discoveryNode.getId())
+            .build();
 
         final Settings.Builder settingsBuilder = Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), discoveryNode.getName());
         if (randomBoolean()) {
@@ -87,14 +90,16 @@ protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
             }
         };
 
-        final MasterService masterService = new FakeThreadPoolMasterService(
+        final ClusterManagerService clusterManagerService = new FakeThreadPoolClusterManagerService(
             "test",
-            "masterService",
+            "clusterManagerService",
             threadPool,
-            r -> { fail("master service should not run any tasks"); }
+            r -> {
+                fail("cluster-manager service should not run any tasks");
+            }
         );
 
-        final ClusterService clusterService = new ClusterService(settings, clusterSettings, masterService, clusterApplierService);
+        final ClusterService clusterService = new ClusterService(settings, clusterSettings, clusterManagerService, clusterApplierService);
 
         final FakeClusterInfoServiceClient client = new FakeClusterInfoServiceClient(threadPool);
         final InternalClusterInfoService clusterInfoService = new InternalClusterInfoService(settings, clusterService, threadPool, client);
@@ -102,34 +107,34 @@ protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
         clusterInfoService.addListener(ignored -> {});
 
         clusterService.setNodeConnectionsService(ClusterServiceUtils.createNoOpNodeConnectionsService());
-        clusterApplierService.setInitialState(ClusterState.builder(new ClusterName("cluster")).nodes(noMaster).build());
-        masterService.setClusterStatePublisher((clusterChangedEvent, publishListener, ackListener) -> fail("should not publish"));
-        masterService.setClusterStateSupplier(clusterApplierService::state);
+        clusterApplierService.setInitialState(ClusterState.builder(new ClusterName("cluster")).nodes(noClusterManager).build());
+        clusterManagerService.setClusterStatePublisher((clusterChangedEvent, publishListener, ackListener) -> fail("should not publish"));
+        clusterManagerService.setClusterStateSupplier(clusterApplierService::state);
         clusterService.start();
 
-        final AtomicBoolean becameMaster1 = new AtomicBoolean();
+        final AtomicBoolean becameClusterManager1 = new AtomicBoolean();
         clusterApplierService.onNewClusterState(
-            "become master 1",
-            () -> ClusterState.builder(new ClusterName("cluster")).nodes(localMaster).build(),
-            setFlagOnSuccess(becameMaster1)
+            "become cluster-manager 1",
+            () -> ClusterState.builder(new ClusterName("cluster")).nodes(localClusterManager).build(),
+            setFlagOnSuccess(becameClusterManager1)
         );
-        runUntilFlag(deterministicTaskQueue, becameMaster1);
+        runUntilFlag(deterministicTaskQueue, becameClusterManager1);
 
-        final AtomicBoolean failMaster1 = new AtomicBoolean();
+        final AtomicBoolean failClusterManager1 = new AtomicBoolean();
         clusterApplierService.onNewClusterState(
-            "fail master 1",
-            () -> ClusterState.builder(new ClusterName("cluster")).nodes(noMaster).build(),
-            setFlagOnSuccess(failMaster1)
+            "fail cluster-manager 1",
+            () -> ClusterState.builder(new ClusterName("cluster")).nodes(noClusterManager).build(),
+            setFlagOnSuccess(failClusterManager1)
         );
-        runUntilFlag(deterministicTaskQueue, failMaster1);
+        runUntilFlag(deterministicTaskQueue, failClusterManager1);
 
-        final AtomicBoolean becameMaster2 = new AtomicBoolean();
+        final AtomicBoolean becameClusterManager2 = new AtomicBoolean();
         clusterApplierService.onNewClusterState(
-            "become master 2",
-            () -> ClusterState.builder(new ClusterName("cluster")).nodes(localMaster).build(),
-            setFlagOnSuccess(becameMaster2)
+            "become cluster-manager 2",
+            () -> ClusterState.builder(new ClusterName("cluster")).nodes(localClusterManager).build(),
+            setFlagOnSuccess(becameClusterManager2)
         );
-        runUntilFlag(deterministicTaskQueue, becameMaster2);
+        runUntilFlag(deterministicTaskQueue, becameClusterManager2);
 
         for (int i = 0; i < 3; i++) {
             final int initialRequestCount = client.requestCount;
@@ -139,13 +144,13 @@ protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
             assertThat(client.requestCount, equalTo(initialRequestCount + 2)); // should have run two client requests per interval
         }
 
-        final AtomicBoolean failMaster2 = new AtomicBoolean();
+        final AtomicBoolean failClusterManager2 = new AtomicBoolean();
         clusterApplierService.onNewClusterState(
-            "fail master 2",
-            () -> ClusterState.builder(new ClusterName("cluster")).nodes(noMaster).build(),
-            setFlagOnSuccess(failMaster2)
+            "fail cluster-manager 2",
+            () -> ClusterState.builder(new ClusterName("cluster")).nodes(noClusterManager).build(),
+            setFlagOnSuccess(failClusterManager2)
         );
-        runUntilFlag(deterministicTaskQueue, failMaster2);
+        runUntilFlag(deterministicTaskQueue, failClusterManager2);
 
         runFor(deterministicTaskQueue, INTERNAL_CLUSTER_INFO_UPDATE_INTERVAL_SETTING.get(settings).millis());
         deterministicTaskQueue.runAllRunnableTasks();
@@ -207,9 +212,7 @@ protected <Request extends ActionRequest, Response extends ActionResponse> void
             if (request instanceof NodesStatsRequest || request instanceof IndicesStatsRequest) {
                 requestCount++;
                 // ClusterInfoService handles ClusterBlockExceptions quietly, so we invent such an exception to avoid excess logging
-                listener.onFailure(
-                    new ClusterBlockException(org.opensearch.common.collect.Set.of(NoMasterBlockService.NO_MASTER_BLOCK_ALL))
-                );
+                listener.onFailure(new ClusterBlockException(Set.of(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL)));
             } else {
                 fail("unexpected action: " + action.name());
             }
diff --git a/server/src/test/java/org/opensearch/cluster/NodeConnectionsServiceTests.java b/server/src/test/java/org/opensearch/cluster/NodeConnectionsServiceTests.java
index 511c1555f1159..4cf82f1dabab3 100644
--- a/server/src/test/java/org/opensearch/cluster/NodeConnectionsServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/NodeConnectionsServiceTests.java
@@ -37,7 +37,6 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -45,13 +44,15 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleListener;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -552,7 +553,8 @@ private TestTransportService(Transport transport, ThreadPool threadPool) {
                 TransportService.NOOP_TRANSPORT_INTERCEPTOR,
                 boundAddress -> DiscoveryNode.createLocal(Settings.EMPTY, buildNewFakeTransportAddress(), UUIDs.randomBase64UUID()),
                 null,
-                emptySet()
+                emptySet(),
+                NoopTracer.INSTANCE
             );
         }
 
diff --git a/server/src/test/java/org/opensearch/cluster/action/index/MappingUpdatedActionTests.java b/server/src/test/java/org/opensearch/cluster/action/index/MappingUpdatedActionTests.java
index 2278d09722fe2..c69cb2c81ad0e 100644
--- a/server/src/test/java/org/opensearch/cluster/action/index/MappingUpdatedActionTests.java
+++ b/server/src/test/java/org/opensearch/cluster/action/index/MappingUpdatedActionTests.java
@@ -33,7 +33,6 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.mapping.put.AutoPutMappingAction;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.AdminClient;
@@ -45,10 +44,10 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.Map;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.mapper.ContentPath;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.Mapping;
@@ -57,6 +56,7 @@
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
@@ -130,13 +130,13 @@ protected void sendUpdateMapping(Index index, Mapping mappingUpdate, ActionListe
         };
 
         PlainActionFuture<Void> fut1 = new PlainActionFuture<>();
-        mua.updateMappingOnMaster(null, null, fut1);
+        mua.updateMappingOnClusterManager(null, null, fut1);
         assertEquals(1, inFlightListeners.size());
         assertEquals(0, mua.blockedThreads());
 
         PlainActionFuture<Void> fut2 = new PlainActionFuture<>();
         Thread thread = new Thread(() -> {
-            mua.updateMappingOnMaster(null, null, fut2); // blocked
+            mua.updateMappingOnClusterManager(null, null, fut2); // blocked
         });
         thread.start();
         assertBusy(() -> assertEquals(1, mua.blockedThreads()));
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/ShardFailedClusterStateTaskExecutorTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/ShardFailedClusterStateTaskExecutorTests.java
index 3632079b97b63..564af1841daee 100644
--- a/server/src/test/java/org/opensearch/cluster/action/shard/ShardFailedClusterStateTaskExecutorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/ShardFailedClusterStateTaskExecutorTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.action.shard;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.lucene.index.CorruptIndexException;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
@@ -59,8 +58,8 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -275,8 +274,8 @@ private List<ShardStateAction.FailedShardEntry> createNonExistentShards(ClusterS
         String nonExistentIndexUUID = "non-existent";
         Index index = new Index("non-existent", nonExistentIndexUUID);
         List<String> nodeIds = new ArrayList<>();
-        for (ObjectCursor<String> nodeId : currentState.nodes().getNodes().keys()) {
-            nodeIds.add(nodeId.toString());
+        for (final String nodeId : currentState.nodes().getNodes().keySet()) {
+            nodeIds.add(nodeId);
         }
         List<ShardRouting> nonExistentShards = new ArrayList<>();
         nonExistentShards.add(nonExistentShardRouting(index, nodeIds, true));
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStartedClusterStateTaskExecutorTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStartedClusterStateTaskExecutorTests.java
index cb87197a53dea..3dee3507ae71a 100644
--- a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStartedClusterStateTaskExecutorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStartedClusterStateTaskExecutorTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.action.shard;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
@@ -45,7 +44,8 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
index 43bee8c7bc6bd..efe91de1ae1a8 100644
--- a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
@@ -33,13 +33,11 @@
 package org.opensearch.cluster.action.shard;
 
 import org.apache.lucene.index.CorruptIndexException;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.replication.ClusterStateCreationUtils;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.action.shard.ShardStateAction.FailedShardEntry;
 import org.opensearch.cluster.action.shard.ShardStateAction.StartedShardEntry;
 import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
@@ -51,11 +49,15 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -64,7 +66,6 @@
 import org.opensearch.transport.NodeNotConnectedException;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 import org.junit.After;
 import org.junit.AfterClass;
@@ -112,29 +113,29 @@ private static class TestShardStateAction extends ShardStateAction {
             super(clusterService, transportService, allocationService, rerouteService, THREAD_POOL);
         }
 
-        private Runnable onBeforeWaitForNewMasterAndRetry;
+        private Runnable onBeforeWaitForNewClusterManagerAndRetry;
 
-        public void setOnBeforeWaitForNewMasterAndRetry(Runnable onBeforeWaitForNewMasterAndRetry) {
-            this.onBeforeWaitForNewMasterAndRetry = onBeforeWaitForNewMasterAndRetry;
+        public void setOnBeforeWaitForNewClusterManagerAndRetry(Runnable onBeforeWaitForNewClusterManagerAndRetry) {
+            this.onBeforeWaitForNewClusterManagerAndRetry = onBeforeWaitForNewClusterManagerAndRetry;
         }
 
-        private Runnable onAfterWaitForNewMasterAndRetry;
+        private Runnable onAfterWaitForNewClusterManagerAndRetry;
 
-        public void setOnAfterWaitForNewMasterAndRetry(Runnable onAfterWaitForNewMasterAndRetry) {
-            this.onAfterWaitForNewMasterAndRetry = onAfterWaitForNewMasterAndRetry;
+        public void setOnAfterWaitFornewClusterManagerAndRetry(Runnable onAfterWaitFornewClusterManagerAndRetry) {
+            this.onAfterWaitForNewClusterManagerAndRetry = onAfterWaitFornewClusterManagerAndRetry;
         }
 
         @Override
-        protected void waitForNewMasterAndRetry(
+        protected void waitForNewClusterManagerAndRetry(
             String actionName,
             ClusterStateObserver observer,
             TransportRequest request,
             ActionListener<Void> listener,
             Predicate<ClusterState> changePredicate
         ) {
-            onBeforeWaitForNewMasterAndRetry.run();
-            super.waitForNewMasterAndRetry(actionName, observer, request, listener, changePredicate);
-            onAfterWaitForNewMasterAndRetry.run();
+            onBeforeWaitForNewClusterManagerAndRetry.run();
+            super.waitForNewClusterManagerAndRetry(actionName, observer, request, listener, changePredicate);
+            onAfterWaitForNewClusterManagerAndRetry.run();
         }
     }
 
@@ -155,13 +156,14 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
         shardStateAction = new TestShardStateAction(clusterService, transportService, null, null);
-        shardStateAction.setOnBeforeWaitForNewMasterAndRetry(() -> {});
-        shardStateAction.setOnAfterWaitForNewMasterAndRetry(() -> {});
+        shardStateAction.setOnBeforeWaitForNewClusterManagerAndRetry(() -> {});
+        shardStateAction.setOnAfterWaitFornewClusterManagerAndRetry(() -> {});
     }
 
     @Override
@@ -196,8 +198,8 @@ public void testSuccess() throws InterruptedException {
         // for the right shard
         assertEquals(shardEntry.shardId, shardRouting.shardId());
         assertEquals(shardEntry.allocationId, shardRouting.allocationId().getId());
-        // sent to the master
-        assertEquals(clusterService.state().nodes().getMasterNode().getId(), capturedRequests[0].node.getId());
+        // sent to the cluster-manager
+        assertEquals(clusterService.state().nodes().getClusterManagerNode().getId(), capturedRequests[0].node.getId());
 
         transport.handleResponse(capturedRequests[0].requestId, TransportResponse.Empty.INSTANCE);
 
@@ -205,20 +207,20 @@ public void testSuccess() throws InterruptedException {
         assertNull(listener.failure.get());
     }
 
-    public void testNoMaster() throws InterruptedException {
+    public void testNoClusterManager() throws InterruptedException {
         final String index = "test";
 
         setState(clusterService, ClusterStateCreationUtils.stateWithActivePrimary(index, true, randomInt(5)));
 
-        DiscoveryNodes.Builder noMasterBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
-        noMasterBuilder.masterNodeId(null);
-        setState(clusterService, ClusterState.builder(clusterService.state()).nodes(noMasterBuilder));
+        DiscoveryNodes.Builder noClusterManagerBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
+        noClusterManagerBuilder.clusterManagerNodeId(null);
+        setState(clusterService, ClusterState.builder(clusterService.state()).nodes(noClusterManagerBuilder));
 
         CountDownLatch latch = new CountDownLatch(1);
         AtomicInteger retries = new AtomicInteger();
         AtomicBoolean success = new AtomicBoolean();
 
-        setUpMasterRetryVerification(1, retries, latch, requestId -> {});
+        setUpClusterManagerRetryVerification(1, retries, latch, requestId -> {});
 
         ShardRouting failedShard = getRandomShardRouting(index);
         shardStateAction.localShardFailed(failedShard, "test", getSimulatedFailure(), new ActionListener<Void>() {
@@ -242,7 +244,7 @@ public void onFailure(Exception e) {
         assertTrue(success.get());
     }
 
-    public void testMasterChannelException() throws InterruptedException {
+    public void testClusterManagerChannelException() throws InterruptedException {
         final String index = "test";
 
         setState(clusterService, ClusterStateCreationUtils.stateWithActivePrimary(index, true, randomInt(5)));
@@ -256,7 +258,7 @@ public void testMasterChannelException() throws InterruptedException {
             if (randomBoolean()) {
                 transport.handleRemoteError(
                     requestId,
-                    randomFrom(new NotMasterException("simulated"), new FailedToCommitClusterStateException("simulated"))
+                    randomFrom(new NotClusterManagerException("simulated"), new FailedToCommitClusterStateException("simulated"))
                 );
             } else {
                 if (randomBoolean()) {
@@ -268,7 +270,7 @@ public void testMasterChannelException() throws InterruptedException {
         };
 
         final int numberOfRetries = randomIntBetween(1, 256);
-        setUpMasterRetryVerification(numberOfRetries, retries, latch, retryLoop);
+        setUpClusterManagerRetryVerification(numberOfRetries, retries, latch, retryLoop);
 
         ShardRouting failedShard = getRandomShardRouting(index);
         shardStateAction.localShardFailed(failedShard, "test", getSimulatedFailure(), new ActionListener<Void>() {
@@ -413,8 +415,8 @@ public void testRemoteShardFailedConcurrently() throws Exception {
         }
         Thread[] clientThreads = new Thread[between(1, 6)];
         int iterationsPerThread = scaledRandomIntBetween(50, 500);
-        Phaser barrier = new Phaser(clientThreads.length + 2); // one for master thread, one for the main thread
-        Thread masterThread = new Thread(() -> {
+        Phaser barrier = new Phaser(clientThreads.length + 2); // one for cluster-manager thread, one for the main thread
+        Thread clusterManagerThread = new Thread(() -> {
             barrier.arriveAndAwaitAdvance();
             while (shutdown.get() == false) {
                 for (CapturingTransport.CapturedRequest request : transport.getCapturedRequestsAndClear()) {
@@ -426,7 +428,7 @@ public void testRemoteShardFailedConcurrently() throws Exception {
                 }
             }
         });
-        masterThread.start();
+        clusterManagerThread.start();
 
         AtomicInteger notifiedResponses = new AtomicInteger();
         for (int t = 0; t < clientThreads.length; t++) {
@@ -463,7 +465,7 @@ public void onFailure(Exception e) {
         }
         assertBusy(() -> assertThat(notifiedResponses.get(), equalTo(clientThreads.length * iterationsPerThread)));
         shutdown.set(true);
-        masterThread.join();
+        clusterManagerThread.join();
     }
 
     public void testShardStarted() throws InterruptedException {
@@ -496,14 +498,21 @@ private ShardRouting getRandomShardRouting(String index) {
         return shardRouting;
     }
 
-    private void setUpMasterRetryVerification(int numberOfRetries, AtomicInteger retries, CountDownLatch latch, LongConsumer retryLoop) {
-        shardStateAction.setOnBeforeWaitForNewMasterAndRetry(() -> {
-            DiscoveryNodes.Builder masterBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
-            masterBuilder.masterNodeId(clusterService.state().nodes().getMasterNodes().iterator().next().value.getId());
-            setState(clusterService, ClusterState.builder(clusterService.state()).nodes(masterBuilder));
+    private void setUpClusterManagerRetryVerification(
+        int numberOfRetries,
+        AtomicInteger retries,
+        CountDownLatch latch,
+        LongConsumer retryLoop
+    ) {
+        shardStateAction.setOnBeforeWaitForNewClusterManagerAndRetry(() -> {
+            DiscoveryNodes.Builder clusterManagerBuilder = DiscoveryNodes.builder(clusterService.state().nodes());
+            clusterManagerBuilder.clusterManagerNodeId(
+                clusterService.state().nodes().getClusterManagerNodes().values().iterator().next().getId()
+            );
+            setState(clusterService, ClusterState.builder(clusterService.state()).nodes(clusterManagerBuilder));
         });
 
-        shardStateAction.setOnAfterWaitForNewMasterAndRetry(() -> verifyRetry(numberOfRetries, retries, latch, retryLoop));
+        shardStateAction.setOnAfterWaitFornewClusterManagerAndRetry(() -> verifyRetry(numberOfRetries, retries, latch, retryLoop));
     }
 
     private void verifyRetry(int numberOfRetries, AtomicInteger retries, CountDownLatch latch, LongConsumer retryLoop) {
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingRequestTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingRequestTests.java
new file mode 100644
index 0000000000000..0a4dad4cbc597
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingRequestTests.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.action.shard.routing.weighted.get;
+
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequest;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ClusterGetWeightedRoutingRequestTests extends OpenSearchTestCase {
+
+    public void testValidate_AwarenessAttributeIsSet() {
+        ClusterGetWeightedRoutingRequest request = new ClusterGetWeightedRoutingRequest();
+        request.setAwarenessAttribute("zone");
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNull(actionRequestValidationException);
+    }
+
+    public void testValidate_AwarenessAttributeNotSet() {
+        ClusterGetWeightedRoutingRequest request = new ClusterGetWeightedRoutingRequest();
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(actionRequestValidationException.getMessage().contains("Awareness attribute is missing"));
+    }
+
+    public void testValidate_AwarenessAttributeIsEmpty() {
+        ClusterGetWeightedRoutingRequest request = new ClusterGetWeightedRoutingRequest();
+        request.setAwarenessAttribute("");
+        ActionRequestValidationException actionRequestValidationException = request.validate();
+        assertNotNull(actionRequestValidationException);
+        assertTrue(actionRequestValidationException.getMessage().contains("Awareness attribute is missing"));
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingResponseTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingResponseTests.java
new file mode 100644
index 0000000000000..47fed71815f05
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/ClusterGetWeightedRoutingResponseTests.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.action.shard.routing.weighted.get;
+
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingResponse;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+import java.util.Map;
+
+public class ClusterGetWeightedRoutingResponseTests extends AbstractXContentTestCase<ClusterGetWeightedRoutingResponse> {
+    @Override
+    protected ClusterGetWeightedRoutingResponse createTestInstance() {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 0.0, "zone_C", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("", weights);
+        ClusterGetWeightedRoutingResponse response = new ClusterGetWeightedRoutingResponse(weightedRouting, true, 0);
+        return response;
+    }
+
+    @Override
+    protected ClusterGetWeightedRoutingResponse doParseInstance(XContentParser parser) throws IOException {
+        return ClusterGetWeightedRoutingResponse.fromXContent(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return false;
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/TransportGetWeightedRoutingActionTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/TransportGetWeightedRoutingActionTests.java
new file mode 100644
index 0000000000000..775d113f986ca
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/routing/weighted/get/TransportGetWeightedRoutingActionTests.java
@@ -0,0 +1,264 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.action.shard.routing.weighted.get;
+
+import org.opensearch.Version;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingRequestBuilder;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.ClusterGetWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.get.TransportGetWeightedRoutingAction;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.ActionTestUtils;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.routing.WeightedRoutingService;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static java.util.Collections.emptySet;
+import static org.mockito.Mockito.mock;
+
+public class TransportGetWeightedRoutingActionTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private WeightedRoutingService weightedRoutingService;
+    private TransportGetWeightedRoutingAction transportGetWeightedRoutingAction;
+    private ClusterSettings clusterSettings;
+    NodeClient client;
+
+    final private static Set<DiscoveryNodeRole> CLUSTER_MANAGER_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+    );
+
+    final private static Set<DiscoveryNodeRole> DATA_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.DATA_ROLE))
+    );
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("test", Settings.EMPTY);
+        clusterService = ClusterServiceUtils.createClusterService(threadPool);
+    }
+
+    @Before
+    public void setUpService() {
+        ClusterState clusterState = ClusterState.builder(new ClusterName("test")).build();
+        clusterState = addClusterManagerNodes(clusterState);
+        clusterState = addDataNodes(clusterState);
+        clusterState = setLocalNode(clusterState, "nodeA1");
+
+        ClusterState.Builder builder = ClusterState.builder(clusterState);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        final MockTransport transport = new MockTransport();
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundTransportAddress -> clusterService.state().nodes().get("nodes1"),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+        Settings.Builder settingsBuilder = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone");
+
+        clusterSettings = new ClusterSettings(settingsBuilder.build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        this.weightedRoutingService = new WeightedRoutingService(clusterService, threadPool, settingsBuilder.build(), clusterSettings);
+
+        this.transportGetWeightedRoutingAction = new TransportGetWeightedRoutingAction(
+            transportService,
+            clusterService,
+            weightedRoutingService,
+            threadPool,
+            new ActionFilters(emptySet()),
+            mock(IndexNameExpressionResolver.class)
+        );
+        client = new NodeClient(Settings.EMPTY, threadPool);
+    }
+
+    private ClusterState addDataNodes(ClusterState clusterState) {
+        clusterState = addDataNodeForAZone(clusterState, "zone_A", "nodeA1", "nodeA2", "nodeA3");
+        clusterState = addDataNodeForAZone(clusterState, "zone_B", "nodeB1", "nodeB2", "nodeB3");
+        clusterState = addDataNodeForAZone(clusterState, "zone_C", "nodeC1", "nodeC2", "nodeC3");
+        return clusterState;
+    }
+
+    private ClusterState addClusterManagerNodes(ClusterState clusterState) {
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_A", "nodeMA");
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_B", "nodeMB");
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_C", "nodeMC");
+        return clusterState;
+    }
+
+    private ClusterState addDataNodeForAZone(ClusterState clusterState, String zone, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds)
+            .forEach(
+                nodeId -> nodeBuilder.add(
+                    new DiscoveryNode(
+                        nodeId,
+                        buildNewFakeTransportAddress(),
+                        Collections.singletonMap("zone", zone),
+                        DATA_ROLE,
+                        Version.CURRENT
+                    )
+                )
+            );
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState addClusterManagerNodeForAZone(ClusterState clusterState, String zone, String... nodeIds) {
+
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds)
+            .forEach(
+                nodeId -> nodeBuilder.add(
+                    new DiscoveryNode(
+                        nodeId,
+                        buildNewFakeTransportAddress(),
+                        Collections.singletonMap("zone", zone),
+                        CLUSTER_MANAGER_ROLE,
+                        Version.CURRENT
+                    )
+                )
+            );
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setLocalNode(ClusterState clusterState, String nodeId) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        nodeBuilder.localNodeId(nodeId);
+        nodeBuilder.clusterManagerNodeId(nodeId);
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setWeightedRoutingWeights(ClusterState clusterState, Map<String, Double> weights) {
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+        return clusterState;
+    }
+
+    public void testGetWeightedRouting_WeightsNotSetInMetadata() {
+
+        final ClusterGetWeightedRoutingRequestBuilder request = new ClusterGetWeightedRoutingRequestBuilder(
+            client,
+            ClusterGetWeightedRoutingAction.INSTANCE
+        );
+        request.setAwarenessAttribute("zone");
+        ClusterState state = clusterService.state();
+
+        ClusterGetWeightedRoutingResponse response = ActionTestUtils.executeBlocking(transportGetWeightedRoutingAction, request.request());
+        assertEquals(response.weights(), null);
+    }
+
+    public void testGetWeightedRouting_WeightsSetInMetadata() {
+        ClusterGetWeightedRoutingRequestBuilder request = new ClusterGetWeightedRoutingRequestBuilder(
+            client,
+            ClusterGetWeightedRoutingAction.INSTANCE
+        );
+        request.setAwarenessAttribute("zone");
+
+        ClusterState state = clusterService.state();
+        state = setLocalNode(state, "nodeB1");
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 0.0, "zone_C", 1.0);
+        state = setWeightedRoutingWeights(state, weights);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterGetWeightedRoutingResponse response = ActionTestUtils.executeBlocking(transportGetWeightedRoutingAction, request.request());
+        assertEquals(weights, response.weights().weights());
+    }
+
+    public void testGetWeightedRoutingLocalWeight_WeightsSetInMetadata() {
+
+        ClusterGetWeightedRoutingRequestBuilder request = new ClusterGetWeightedRoutingRequestBuilder(
+            client,
+            ClusterGetWeightedRoutingAction.INSTANCE
+        );
+
+        request.setRequestLocal(true);
+        request.setAwarenessAttribute("zone");
+
+        ClusterState state = clusterService.state();
+        state = setLocalNode(state, "nodeB1");
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 0.0, "zone_C", 1.0);
+        state = setWeightedRoutingWeights(state, weights);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterGetWeightedRoutingResponse response = ActionTestUtils.executeBlocking(transportGetWeightedRoutingAction, request.request());
+        assertEquals(true, response.getDiscoveredClusterManager());
+        assertEquals(weights, response.getWeightedRouting().weights());
+    }
+
+    public void testGetWeightedRoutingLocalWeight_WeightsNotSetInMetadata() {
+
+        ClusterGetWeightedRoutingRequestBuilder request = new ClusterGetWeightedRoutingRequestBuilder(
+            client,
+            ClusterGetWeightedRoutingAction.INSTANCE
+        );
+
+        request.setRequestLocal(true);
+        request.setAwarenessAttribute("zone");
+
+        ClusterState state = clusterService.state();
+        state = setLocalNode(state, "nodeB1");
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterGetWeightedRoutingResponse response = ActionTestUtils.executeBlocking(transportGetWeightedRoutingAction, request.request());
+        assertEquals(null, response.getWeightedRouting());
+    }
+
+    @After
+    public void shutdown() {
+        clusterService.stop();
+        threadPool.shutdown();
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealthTests.java b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealthTests.java
new file mode 100644
index 0000000000000..ddd8b635ae84a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributeValueHealthTests.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractSerializingTestCase;
+
+import java.io.IOException;
+
+public class ClusterAwarenessAttributeValueHealthTests extends AbstractSerializingTestCase<ClusterAwarenessAttributeValueHealth> {
+
+    @Override
+    protected Writeable.Reader<ClusterAwarenessAttributeValueHealth> instanceReader() {
+        return ClusterAwarenessAttributeValueHealth::new;
+    }
+
+    @Override
+    protected ClusterAwarenessAttributeValueHealth createTestInstance() {
+        return new ClusterAwarenessAttributeValueHealth(
+            randomFrom("zone-1", "zone-2", "zone-3"),
+            randomInt(1000),
+            randomInt(1000),
+            randomInt(1000),
+            randomInt(1000),
+            randomInt(1000),
+            randomFrom(0.0, 1.0)
+        );
+    }
+
+    @Override
+    protected ClusterAwarenessAttributeValueHealth doParseInstance(XContentParser parser) throws IOException {
+        return ClusterAwarenessAttributeValueHealth.fromXContent(parser);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthSerializationTests.java b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthSerializationTests.java
new file mode 100644
index 0000000000000..a6cf687f5892b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthSerializationTests.java
@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractSerializingTestCase;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ClusterAwarenessAttributesHealthSerializationTests extends AbstractSerializingTestCase<ClusterAwarenessAttributesHealth> {
+
+    @Override
+    protected ClusterAwarenessAttributesHealth doParseInstance(XContentParser parser) throws IOException {
+        return ClusterAwarenessAttributesHealth.fromXContent(parser);
+    }
+
+    @Override
+    protected Writeable.Reader<ClusterAwarenessAttributesHealth> instanceReader() {
+        return ClusterAwarenessAttributesHealth::new;
+    }
+
+    @Override
+    protected ClusterAwarenessAttributesHealth createTestInstance() {
+        Map<String, ClusterAwarenessAttributeValueHealth> clusterAwarenessAttributeValueHealthMap = new HashMap<>();
+        ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth1 = new ClusterAwarenessAttributeValueHealth(
+            "zone-1",
+            2,
+            0,
+            0,
+            2,
+            2,
+            1.0
+        );
+
+        ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth2 = new ClusterAwarenessAttributeValueHealth(
+            "zone-2",
+            2,
+            0,
+            0,
+            2,
+            2,
+            1.0
+        );
+
+        ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth3 = new ClusterAwarenessAttributeValueHealth(
+            "zone-3",
+            2,
+            0,
+            0,
+            2,
+            2,
+            0.0
+        );
+
+        clusterAwarenessAttributeValueHealthMap.put(clusterAwarenessAttributeValueHealth1.getName(), clusterAwarenessAttributeValueHealth1);
+        clusterAwarenessAttributeValueHealthMap.put(clusterAwarenessAttributeValueHealth2.getName(), clusterAwarenessAttributeValueHealth2);
+        clusterAwarenessAttributeValueHealthMap.put(clusterAwarenessAttributeValueHealth3.getName(), clusterAwarenessAttributeValueHealth3);
+
+        return new ClusterAwarenessAttributesHealth("zone", clusterAwarenessAttributeValueHealthMap);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthTests.java b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthTests.java
new file mode 100644
index 0000000000000..7910daebb00de
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessAttributesHealthTests.java
@@ -0,0 +1,225 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.Collections.singletonMap;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+
+public class ClusterAwarenessAttributesHealthTests extends OpenSearchTestCase {
+
+    private static ThreadPool threadPool;
+
+    private ClusterService clusterService;
+    private TransportService transportService;
+
+    protected static Set<DiscoveryNodeRole> NODE_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE, DiscoveryNodeRole.DATA_ROLE))
+    );
+
+    @BeforeClass
+    public static void setupThreadPool() {
+        threadPool = new TestThreadPool("ClusterAwarenessAttributeHealthTests");
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        clusterService = createClusterService(threadPool);
+        CapturingTransport transport = new CapturingTransport();
+        transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            x -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        clusterService.close();
+        transportService.close();
+    }
+
+    @AfterClass
+    public static void terminateThreadPool() {
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+        threadPool = null;
+    }
+
+    public void testClusterAwarenessAttributeHealth() {
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        ClusterAwarenessAttributesHealth clusterAwarenessAttributesHealth = new ClusterAwarenessAttributesHealth(
+            "zone",
+            true,
+            clusterState
+        );
+
+        assertEquals("zone", clusterAwarenessAttributesHealth.getAwarenessAttributeName());
+        Map<String, ClusterAwarenessAttributeValueHealth> attributeValueMap = clusterAwarenessAttributesHealth
+            .getAwarenessAttributeHealthMap();
+        assertEquals(3, attributeValueMap.size());
+    }
+
+    public void testClusterAwarenessAttributeHealthNodeAttributeDoesNotExists() {
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        ClusterAwarenessAttributesHealth clusterAwarenessAttributesHealth = new ClusterAwarenessAttributesHealth(
+            "rack",
+            true,
+            clusterState
+        );
+
+        assertEquals("rack", clusterAwarenessAttributesHealth.getAwarenessAttributeName());
+        Map<String, ClusterAwarenessAttributeValueHealth> attributeValueMap = clusterAwarenessAttributesHealth
+            .getAwarenessAttributeHealthMap();
+        assertEquals(0, attributeValueMap.size());
+    }
+
+    public void testClusterAwarenessAttributeHealthNoReplicaEnforcement() {
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        ClusterAwarenessAttributesHealth clusterAwarenessAttributesHealth = new ClusterAwarenessAttributesHealth(
+            "zone",
+            false,
+            clusterState
+        );
+
+        assertEquals("zone", clusterAwarenessAttributesHealth.getAwarenessAttributeName());
+        Map<String, ClusterAwarenessAttributeValueHealth> attributeValueMap = clusterAwarenessAttributesHealth
+            .getAwarenessAttributeHealthMap();
+        assertEquals(3, attributeValueMap.size());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealthTests.java b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealthTests.java
new file mode 100644
index 0000000000000..b68f0f2375354
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/awarenesshealth/ClusterAwarenessHealthTests.java
@@ -0,0 +1,421 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.awarenesshealth;
+
+import org.opensearch.Version;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.RoutingTableGenerator;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.Collections.singletonMap;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+
+public class ClusterAwarenessHealthTests extends OpenSearchTestCase {
+
+    private final IndexNameExpressionResolver indexNameExpressionResolver = new IndexNameExpressionResolver(
+        new ThreadContext(Settings.EMPTY)
+    );
+
+    private static ThreadPool threadPool;
+
+    private ClusterService clusterService;
+    private TransportService transportService;
+
+    protected static Set<DiscoveryNodeRole> NODE_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE, DiscoveryNodeRole.DATA_ROLE))
+    );
+
+    @BeforeClass
+    public static void setupThreadPool() {
+        threadPool = new TestThreadPool("ClusterAwarenessHealthTests");
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        clusterService = createClusterService(threadPool);
+        CapturingTransport transport = new CapturingTransport();
+        transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            x -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        clusterService.close();
+        transportService.close();
+    }
+
+    @AfterClass
+    public static void terminateThreadPool() {
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+        threadPool = null;
+    }
+
+    public void testClusterHealthWithNoAwarenessAttribute() throws IOException {
+        RoutingTableGenerator routingTableGenerator = new RoutingTableGenerator();
+        RoutingTableGenerator.ShardCounter counter = new RoutingTableGenerator.ShardCounter();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        Metadata.Builder metadata = Metadata.builder();
+        for (int i = 4; i >= 0; i--) {
+            int numberOfShards = randomInt(3) + 1;
+            int numberOfReplicas = randomInt(4);
+            IndexMetadata indexMetadata = IndexMetadata.builder("test_" + i)
+                .settings(settings(Version.CURRENT))
+                .numberOfShards(numberOfShards)
+                .numberOfReplicas(numberOfReplicas)
+                .build();
+            IndexRoutingTable indexRoutingTable = routingTableGenerator.genIndexRoutingTable(indexMetadata, counter);
+            metadata.put(indexMetadata, true);
+            routingTable.add(indexRoutingTable);
+        }
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable.build())
+            .nodes(clusterService.state().nodes())
+            .build();
+
+        indexNameExpressionResolver.concreteIndexNames(clusterState, IndicesOptions.strictExpand(), (String[]) null);
+
+        ClusterAwarenessHealth clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, "zone");
+        clusterAwarenessHealth = serializeResponse(clusterAwarenessHealth);
+        Map<String, ClusterAwarenessAttributesHealth> attributeHealthMap = clusterAwarenessHealth.getClusterAwarenessAttributesHealthMap();
+        for (String attributesName : attributeHealthMap.keySet()) {
+            assertEquals("zone", attributesName);
+            assertEquals(0, attributeHealthMap.get(attributesName).getAwarenessAttributeHealthMap().size());
+        }
+    }
+
+    ClusterAwarenessHealth serializeResponse(ClusterAwarenessHealth clusterAwarenessHealth) throws IOException {
+        if (randomBoolean()) {
+            BytesStreamOutput out = new BytesStreamOutput();
+            clusterAwarenessHealth.writeTo(out);
+            StreamInput in = out.bytes().streamInput();
+            clusterAwarenessHealth = new ClusterAwarenessHealth(in);
+        }
+        return clusterAwarenessHealth;
+    }
+
+    public void testClusterHealthWithAwarenessAttributeAndNoNodeAttribute() throws IOException {
+        RoutingTableGenerator routingTableGenerator = new RoutingTableGenerator();
+        RoutingTableGenerator.ShardCounter counter = new RoutingTableGenerator.ShardCounter();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        Metadata.Builder metadata = Metadata.builder();
+        for (int i = 4; i >= 0; i--) {
+            int numberOfShards = randomInt(3) + 1;
+            int numberOfReplicas = randomInt(4);
+            IndexMetadata indexMetadata = IndexMetadata.builder("test_" + i)
+                .settings(settings(Version.CURRENT))
+                .numberOfShards(numberOfShards)
+                .numberOfReplicas(numberOfReplicas)
+                .build();
+            IndexRoutingTable indexRoutingTable = routingTableGenerator.genIndexRoutingTable(indexMetadata, counter);
+            metadata.put(indexMetadata, true);
+            routingTable.add(indexRoutingTable);
+        }
+
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .build();
+
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable.build())
+            .nodes(clusterService.state().nodes())
+            .build();
+
+        indexNameExpressionResolver.concreteIndexNames(clusterState, IndicesOptions.strictExpand(), (String[]) null);
+
+        ClusterAwarenessHealth clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, "zone");
+        clusterAwarenessHealth = serializeResponse(clusterAwarenessHealth);
+        Map<String, ClusterAwarenessAttributesHealth> attributeHealthMap = clusterAwarenessHealth.getClusterAwarenessAttributesHealthMap();
+        for (String attributesName : attributeHealthMap.keySet()) {
+            assertEquals("zone", attributesName);
+            assertEquals(0, attributeHealthMap.get(attributesName).getAwarenessAttributeHealthMap().size());
+        }
+    }
+
+    public void testClusterHealthWithAwarenessAttributeAndNodeAttribute() throws IOException {
+        RoutingTableGenerator routingTableGenerator = new RoutingTableGenerator();
+        RoutingTableGenerator.ShardCounter counter = new RoutingTableGenerator.ShardCounter();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        Metadata.Builder metadata = Metadata.builder();
+        for (int i = 4; i >= 0; i--) {
+            int numberOfShards = randomInt(3) + 1;
+            int numberOfReplicas = randomInt(4);
+            IndexMetadata indexMetadata = IndexMetadata.builder("test_" + i)
+                .settings(settings(Version.CURRENT))
+                .numberOfShards(numberOfShards)
+                .numberOfReplicas(numberOfReplicas)
+                .build();
+            IndexRoutingTable indexRoutingTable = routingTableGenerator.genIndexRoutingTable(indexMetadata, counter);
+            metadata.put(indexMetadata, true);
+            routingTable.add(indexRoutingTable);
+        }
+
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .build();
+
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable.build())
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        indexNameExpressionResolver.concreteIndexNames(clusterState, IndicesOptions.strictExpand(), (String[]) null);
+
+        ClusterAwarenessHealth clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, "zone");
+        clusterAwarenessHealth = serializeResponse(clusterAwarenessHealth);
+        Map<String, ClusterAwarenessAttributesHealth> attributeHealthMap = clusterAwarenessHealth.getClusterAwarenessAttributesHealthMap();
+        for (String attributesName : attributeHealthMap.keySet()) {
+            assertEquals("zone", attributesName);
+            assertEquals(3, attributeHealthMap.get(attributesName).getAwarenessAttributeHealthMap().size());
+            for (ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth : attributeHealthMap.get(attributesName)
+                .getAwarenessAttributeHealthMap()
+                .values()) {
+                assertEquals(-1, clusterAwarenessAttributeValueHealth.getUnassignedShards());
+            }
+        }
+    }
+
+    public void testClusterHealthWithAwarenessAttributeAndReplicaEnforcementEnabled() throws IOException {
+        RoutingTableGenerator routingTableGenerator = new RoutingTableGenerator();
+        RoutingTableGenerator.ShardCounter counter = new RoutingTableGenerator.ShardCounter();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        Metadata.Builder metadata = Metadata.builder();
+        for (int i = 4; i >= 0; i--) {
+            int numberOfShards = 1;
+            int numberOfReplicas = 5;
+            IndexMetadata indexMetadata = IndexMetadata.builder("test_" + i)
+                .settings(settings(Version.CURRENT))
+                .numberOfShards(numberOfShards)
+                .numberOfReplicas(numberOfReplicas)
+                .build();
+            IndexRoutingTable indexRoutingTable = routingTableGenerator.genIndexRoutingTable(indexMetadata, counter);
+            metadata.put(indexMetadata, true);
+            routingTable.add(indexRoutingTable);
+        }
+
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone" + ".values", "a,b,c")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), "true")
+            .build();
+
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable.build())
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        indexNameExpressionResolver.concreteIndexNames(clusterState, IndicesOptions.strictExpand(), (String[]) null);
+
+        ClusterAwarenessHealth clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, "zone");
+        clusterAwarenessHealth = serializeResponse(clusterAwarenessHealth);
+        Map<String, ClusterAwarenessAttributesHealth> attributeHealthMap = clusterAwarenessHealth.getClusterAwarenessAttributesHealthMap();
+        for (String attributesName : attributeHealthMap.keySet()) {
+            assertEquals("zone", attributesName);
+            assertEquals(3, attributeHealthMap.get(attributesName).getAwarenessAttributeHealthMap().size());
+            for (ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth : attributeHealthMap.get(attributesName)
+                .getAwarenessAttributeHealthMap()
+                .values()) {
+                assertEquals(1.0, clusterAwarenessAttributeValueHealth.getWeight(), 0.0);
+            }
+        }
+    }
+
+    public void testClusterHealthWithAwarenessAttributeAndReplicaEnforcementNotEnabled() throws IOException {
+        RoutingTableGenerator routingTableGenerator = new RoutingTableGenerator();
+        RoutingTableGenerator.ShardCounter counter = new RoutingTableGenerator.ShardCounter();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        Metadata.Builder metadata = Metadata.builder();
+        for (int i = 4; i >= 0; i--) {
+            int numberOfShards = randomInt(3) + 1;
+            int numberOfReplicas = randomInt(4);
+            IndexMetadata indexMetadata = IndexMetadata.builder("test_" + i)
+                .settings(settings(Version.CURRENT))
+                .numberOfShards(numberOfShards)
+                .numberOfReplicas(numberOfReplicas)
+                .build();
+            IndexRoutingTable indexRoutingTable = routingTableGenerator.genIndexRoutingTable(indexMetadata, counter);
+            metadata.put(indexMetadata, true);
+            routingTable.add(indexRoutingTable);
+        }
+
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), "true")
+            .build();
+
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable.build())
+            .nodes(
+                DiscoveryNodes.builder(clusterService.state().nodes())
+                    .add(
+                        new DiscoveryNode(
+                            "node1",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_1"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node2",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_2"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+                    .add(
+                        new DiscoveryNode(
+                            "node3",
+                            buildNewFakeTransportAddress(),
+                            singletonMap("zone", "zone_3"),
+                            NODE_ROLE,
+                            Version.CURRENT
+                        )
+                    )
+            )
+            .build();
+
+        indexNameExpressionResolver.concreteIndexNames(clusterState, IndicesOptions.strictExpand(), (String[]) null);
+
+        ClusterAwarenessHealth clusterAwarenessHealth = new ClusterAwarenessHealth(clusterState, clusterSettings, "zone");
+        clusterAwarenessHealth = serializeResponse(clusterAwarenessHealth);
+        Map<String, ClusterAwarenessAttributesHealth> attributeHealthMap = clusterAwarenessHealth.getClusterAwarenessAttributesHealthMap();
+        for (String attributesName : attributeHealthMap.keySet()) {
+            assertEquals("zone", attributesName);
+            assertEquals(3, attributeHealthMap.get(attributesName).getAwarenessAttributeHealthMap().size());
+            for (ClusterAwarenessAttributeValueHealth clusterAwarenessAttributeValueHealth : attributeHealthMap.get(attributesName)
+                .getAwarenessAttributeHealthMap()
+                .values()) {
+                assertEquals(-1, clusterAwarenessAttributeValueHealth.getUnassignedShards());
+                assertEquals(1.0, clusterAwarenessAttributeValueHealth.getWeight(), 0.0);
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/block/ClusterBlockTests.java b/server/src/test/java/org/opensearch/cluster/block/ClusterBlockTests.java
index af82e143faa37..04e04bd96a7d3 100644
--- a/server/src/test/java/org/opensearch/cluster/block/ClusterBlockTests.java
+++ b/server/src/test/java/org/opensearch/cluster/block/ClusterBlockTests.java
@@ -34,15 +34,15 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import static java.util.EnumSet.copyOf;
 import static org.opensearch.test.VersionUtils.randomVersion;
@@ -80,7 +80,7 @@ public void testToStringDanglingComma() {
 
     public void testGlobalBlocksCheckedIfNoIndicesSpecified() {
         ClusterBlock globalBlock = randomClusterBlock();
-        ClusterBlocks clusterBlocks = new ClusterBlocks(Collections.singleton(globalBlock), ImmutableOpenMap.of());
+        ClusterBlocks clusterBlocks = new ClusterBlocks(Collections.singleton(globalBlock), Map.of());
         ClusterBlockException exception = clusterBlocks.indicesBlockedException(randomFrom(globalBlock.levels()), new String[0]);
         assertNotNull(exception);
         assertEquals(exception.blocks(), Collections.singleton(globalBlock));
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceDeprecatedMasterTests.java b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceDeprecatedMasterTests.java
new file mode 100644
index 0000000000000..0b84eb19f4264
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceDeprecatedMasterTests.java
@@ -0,0 +1,317 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.discovery.DiscoveryModule;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.transport.TransportRequest;
+import org.opensearch.transport.TransportService;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_MASTER_NODES_SETTING;
+import static org.opensearch.cluster.coordination.ClusterBootstrapService.UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING;
+import static org.opensearch.common.settings.Settings.builder;
+import static org.opensearch.node.Node.NODE_NAME_SETTING;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasItem;
+import static org.hamcrest.Matchers.not;
+
+/*
+ * As of 2.0, MASTER_ROLE and setting 'cluster.initial_master_nodes' is deprecated to promote inclusive language.
+ * This class is a partial copy of ClusterBootstrapServiceTests
+ * to validate ClusterBootstrapService works correctly with the deprecated node role and cluster setting.
+ * Remove the class after the deprecated node role and cluster setting is removed.
+ */
+public class ClusterBootstrapServiceDeprecatedMasterTests extends OpenSearchTestCase {
+
+    private DiscoveryNode localNode, otherNode1, otherNode2;
+    private DeterministicTaskQueue deterministicTaskQueue;
+    private TransportService transportService;
+    private static final String CLUSTER_SETTING_DEPRECATED_MESSAGE =
+        "[cluster.initial_master_nodes] setting was deprecated in OpenSearch and will be removed in a future release! "
+            + "See the breaking changes documentation for the next major version.";
+
+    @Before
+    public void createServices() {
+        localNode = newDiscoveryNode("local");
+        otherNode1 = newDiscoveryNode("other1");
+        otherNode2 = newDiscoveryNode("other2");
+
+        deterministicTaskQueue = new DeterministicTaskQueue(builder().put(NODE_NAME_SETTING.getKey(), "node").build(), random());
+
+        final MockTransport transport = new MockTransport() {
+            @Override
+            protected void onSendRequest(long requestId, String action, TransportRequest request, DiscoveryNode node) {
+                throw new AssertionError("unexpected " + action);
+            }
+        };
+
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            deterministicTaskQueue.getThreadPool(),
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundTransportAddress -> localNode,
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+    }
+
+    private DiscoveryNode newDiscoveryNode(String nodeName) {
+        return new DiscoveryNode(
+            nodeName,
+            randomAlphaOfLength(10),
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.MASTER_ROLE),
+            Version.CURRENT
+        );
+    }
+
+    public void testBootstrapsAutomaticallyWithDefaultConfiguration() {
+        final Settings.Builder settings = Settings.builder();
+        final long timeout;
+        if (randomBoolean()) {
+            timeout = UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING.get(Settings.EMPTY).millis();
+        } else {
+            timeout = randomLongBetween(1, 10000);
+            settings.put(UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING.getKey(), timeout + "ms");
+        }
+
+        final AtomicReference<Supplier<Iterable<DiscoveryNode>>> discoveredNodesSupplier = new AtomicReference<>(() -> {
+            throw new AssertionError("should not be called yet");
+        });
+
+        final AtomicBoolean bootstrapped = new AtomicBoolean();
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
+            settings.build(),
+            transportService,
+            () -> discoveredNodesSupplier.get().get(),
+            () -> false,
+            vc -> {
+                assertTrue(bootstrapped.compareAndSet(false, true));
+                assertThat(
+                    vc.getNodeIds(),
+                    equalTo(Stream.of(localNode, otherNode1, otherNode2).map(DiscoveryNode::getId).collect(Collectors.toSet()))
+                );
+                assertThat(deterministicTaskQueue.getCurrentTimeMillis(), greaterThanOrEqualTo(timeout));
+            }
+        );
+
+        deterministicTaskQueue.scheduleAt(
+            timeout - 1,
+            () -> discoveredNodesSupplier.set(() -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toSet()))
+        );
+
+        transportService.start();
+        clusterBootstrapService.scheduleUnconfiguredBootstrap();
+        deterministicTaskQueue.runAllTasksInTimeOrder();
+        assertTrue(bootstrapped.get());
+    }
+
+    // Validate the deprecated setting is still valid during the cluster bootstrap.
+    public void testDoesNothingByDefaultIfMasterNodesConfigured() {
+        testDoesNothingWithSettings(builder().putList(INITIAL_MASTER_NODES_SETTING.getKey()));
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+    }
+
+    private void testDoesNothingWithSettings(Settings.Builder builder) {
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(builder.build(), transportService, () -> {
+            throw new AssertionError("should not be called");
+        }, () -> false, vc -> { throw new AssertionError("should not be called"); });
+        transportService.start();
+        clusterBootstrapService.scheduleUnconfiguredBootstrap();
+        deterministicTaskQueue.runAllTasks();
+    }
+
+    public void testThrowsExceptionOnDuplicates() {
+        final IllegalArgumentException illegalArgumentException = expectThrows(IllegalArgumentException.class, () -> {
+            new ClusterBootstrapService(
+                builder().putList(INITIAL_MASTER_NODES_SETTING.getKey(), "duplicate-requirement", "duplicate-requirement").build(),
+                transportService,
+                Collections::emptyList,
+                () -> false,
+                vc -> {
+                    throw new AssertionError("should not be called");
+                }
+            );
+        });
+
+        assertThat(illegalArgumentException.getMessage(), containsString(INITIAL_MASTER_NODES_SETTING.getKey()));
+        assertThat(illegalArgumentException.getMessage(), containsString("duplicate-requirement"));
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+    }
+
+    public void testBootstrapsOnDiscoveryOfAllRequiredNodes() {
+        final AtomicBoolean bootstrapped = new AtomicBoolean();
+
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
+            Settings.builder()
+                .putList(INITIAL_MASTER_NODES_SETTING.getKey(), localNode.getName(), otherNode1.getName(), otherNode2.getName())
+                .build(),
+            transportService,
+            () -> Stream.of(otherNode1, otherNode2).collect(Collectors.toList()),
+            () -> false,
+            vc -> {
+                assertTrue(bootstrapped.compareAndSet(false, true));
+                assertThat(vc.getNodeIds(), containsInAnyOrder(localNode.getId(), otherNode1.getId(), otherNode2.getId()));
+                assertThat(vc.getNodeIds(), not(hasItem(containsString("placeholder"))));
+            }
+        );
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+
+        transportService.start();
+        clusterBootstrapService.onFoundPeersUpdated();
+        deterministicTaskQueue.runAllTasks();
+        assertTrue(bootstrapped.get());
+
+        bootstrapped.set(false);
+        clusterBootstrapService.onFoundPeersUpdated();
+        deterministicTaskQueue.runAllTasks();
+        assertFalse(bootstrapped.get()); // should only bootstrap once
+    }
+
+    public void testDoesNotBootstrapsOnNonMasterNode() {
+        localNode = new DiscoveryNode(
+            "local",
+            randomAlphaOfLength(10),
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            emptySet(),
+            Version.CURRENT
+        );
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
+            Settings.builder()
+                .putList(INITIAL_MASTER_NODES_SETTING.getKey(), localNode.getName(), otherNode1.getName(), otherNode2.getName())
+                .build(),
+            transportService,
+            () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
+            () -> false,
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
+        );
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+        transportService.start();
+        clusterBootstrapService.onFoundPeersUpdated();
+        deterministicTaskQueue.runAllTasks();
+    }
+
+    public void testDoesNotBootstrapsIfLocalNodeNotInInitialMasterNodes() {
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
+            Settings.builder().putList(INITIAL_MASTER_NODES_SETTING.getKey(), otherNode1.getName(), otherNode2.getName()).build(),
+            transportService,
+            () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
+            () -> false,
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
+        );
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+        transportService.start();
+        clusterBootstrapService.onFoundPeersUpdated();
+        deterministicTaskQueue.runAllTasks();
+    }
+
+    public void testDoesNotBootstrapsIfNotConfigured() {
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
+            Settings.builder().putList(INITIAL_MASTER_NODES_SETTING.getKey()).build(),
+            transportService,
+            () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
+            () -> false,
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
+        );
+        assertWarnings(CLUSTER_SETTING_DEPRECATED_MESSAGE);
+        transportService.start();
+        clusterBootstrapService.scheduleUnconfiguredBootstrap();
+        clusterBootstrapService.onFoundPeersUpdated();
+        deterministicTaskQueue.runAllTasks();
+    }
+
+    /**
+     * Validate the correct deprecated setting name of cluster.initial_master_nodes is shown in the exception,
+     * when discovery type is single-node.
+     */
+    public void testFailBootstrapWithBothSingleNodeDiscoveryAndInitialMasterNodes() {
+        final Settings.Builder settings = Settings.builder()
+            .put(DiscoveryModule.DISCOVERY_TYPE_SETTING.getKey(), DiscoveryModule.SINGLE_NODE_DISCOVERY_TYPE)
+            .put(NODE_NAME_SETTING.getKey(), localNode.getName())
+            .put(INITIAL_MASTER_NODES_SETTING.getKey(), "test");
+
+        assertThat(
+            expectThrows(
+                IllegalArgumentException.class,
+                () -> new ClusterBootstrapService(settings.build(), transportService, () -> emptyList(), () -> false, vc -> fail())
+            ).getMessage(),
+            containsString(
+                "setting [" + INITIAL_MASTER_NODES_SETTING.getKey() + "] is not allowed when [discovery.type] is set " + "to [single-node]"
+            )
+        );
+    }
+
+    public void testFailBootstrapNonMasterEligibleNodeWithSingleNodeDiscovery() {
+        final Settings.Builder settings = Settings.builder()
+            .put(DiscoveryModule.DISCOVERY_TYPE_SETTING.getKey(), DiscoveryModule.SINGLE_NODE_DISCOVERY_TYPE)
+            .put(NODE_NAME_SETTING.getKey(), localNode.getName())
+            .put(nonClusterManagerNode());
+
+        assertThat(
+            expectThrows(
+                IllegalArgumentException.class,
+                () -> new ClusterBootstrapService(settings.build(), transportService, () -> emptyList(), () -> false, vc -> fail())
+            ).getMessage(),
+            containsString("node with [discovery.type] set to [single-node] must be cluster-manager-eligible")
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceRenamedSettingTests.java b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceRenamedSettingTests.java
index 09fb6a5ea256d..f95e50a22cf5a 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceRenamedSettingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceRenamedSettingTests.java
@@ -25,7 +25,7 @@ public class ClusterBootstrapServiceRenamedSettingTests extends OpenSearchTestCa
     /**
      * Validate the both settings are known and supported.
      */
-    public void testReindexSettingsExist() {
+    public void testClusterBootstrapServiceSettingsExist() {
         Set<Setting<?>> settings = ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
         assertTrue(
             "Both 'cluster.initial_cluster_manager_nodes' and its predecessor should be supported built-in settings.",
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceTests.java b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceTests.java
index 079b31f31f599..bfb225854979b 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/ClusterBootstrapServiceTests.java
@@ -37,6 +37,7 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.discovery.DiscoveryModule;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.transport.TransportRequest;
@@ -58,13 +59,12 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.BOOTSTRAP_PLACEHOLDER_PREFIX;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING;
-import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_MASTER_NODES_SETTING;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING;
 import static org.opensearch.common.settings.Settings.builder;
 import static org.opensearch.discovery.DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING;
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
 import static org.opensearch.node.Node.NODE_NAME_SETTING;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
@@ -102,7 +102,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
     }
 
@@ -127,9 +128,9 @@ public void testBootstrapsAutomaticallyWithDefaultConfiguration() {
             settings.put(UNCONFIGURED_BOOTSTRAP_TIMEOUT_SETTING.getKey(), timeout + "ms");
         }
 
-        final AtomicReference<Supplier<Iterable<DiscoveryNode>>> discoveredNodesSupplier = new AtomicReference<>(
-            () -> { throw new AssertionError("should not be called yet"); }
-        );
+        final AtomicReference<Supplier<Iterable<DiscoveryNode>>> discoveredNodesSupplier = new AtomicReference<>(() -> {
+            throw new AssertionError("should not be called yet");
+        });
 
         final AtomicBoolean bootstrapped = new AtomicBoolean();
         ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
@@ -166,11 +167,11 @@ public void testDoesNothingByDefaultIfSeedHostsConfigured() {
         testDoesNothingWithSettings(builder().putList(DISCOVERY_SEED_HOSTS_SETTING.getKey()));
     }
 
-    public void testDoesNothingByDefaultIfMasterNodesConfigured() {
+    public void testDoesNothingByDefaultIfClusterManagerNodesConfigured() {
         testDoesNothingWithSettings(builder().putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey()));
     }
 
-    public void testDoesNothingByDefaultOnMasterIneligibleNodes() {
+    public void testDoesNothingByDefaultOnClusterManagerIneligibleNodes() {
         localNode = new DiscoveryNode(
             "local",
             randomAlphaOfLength(10),
@@ -183,13 +184,9 @@ public void testDoesNothingByDefaultOnMasterIneligibleNodes() {
     }
 
     private void testDoesNothingWithSettings(Settings.Builder builder) {
-        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
-            builder.build(),
-            transportService,
-            () -> { throw new AssertionError("should not be called"); },
-            () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
-        );
+        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(builder.build(), transportService, () -> {
+            throw new AssertionError("should not be called");
+        }, () -> false, vc -> { throw new AssertionError("should not be called"); });
         transportService.start();
         clusterBootstrapService.scheduleUnconfiguredBootstrap();
         deterministicTaskQueue.runAllTasks();
@@ -202,7 +199,9 @@ public void testThrowsExceptionOnDuplicates() {
                 transportService,
                 Collections::emptyList,
                 () -> false,
-                vc -> { throw new AssertionError("should not be called"); }
+                vc -> {
+                    throw new AssertionError("should not be called");
+                }
             );
         });
 
@@ -331,7 +330,9 @@ public void testDoesNotBootstrapIfNoNodesDiscovered() {
             transportService,
             Collections::emptyList,
             () -> true,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -354,7 +355,9 @@ public void testDoesNotBootstrapIfTwoOfFiveNodesDiscovered() {
             transportService,
             () -> Stream.of(otherNode1).collect(Collectors.toList()),
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -378,7 +381,9 @@ public void testDoesNotBootstrapIfThreeOfSixNodesDiscovered() {
             transportService,
             () -> Stream.of(otherNode1, otherNode2).collect(Collectors.toList()),
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -394,7 +399,9 @@ public void testDoesNotBootstrapIfAlreadyBootstrapped() {
             transportService,
             () -> Stream.of(otherNode1, otherNode2).collect(Collectors.toList()),
             () -> true,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -402,7 +409,7 @@ public void testDoesNotBootstrapIfAlreadyBootstrapped() {
         deterministicTaskQueue.runAllTasks();
     }
 
-    public void testDoesNotBootstrapsOnNonMasterNode() {
+    public void testDoesNotBootstrapsOnNonClusterManagerNode() {
         localNode = new DiscoveryNode(
             "local",
             randomAlphaOfLength(10),
@@ -418,7 +425,9 @@ public void testDoesNotBootstrapsOnNonMasterNode() {
             transportService,
             () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
         transportService.start();
         clusterBootstrapService.onFoundPeersUpdated();
@@ -431,7 +440,9 @@ public void testDoesNotBootstrapsIfLocalNodeNotInInitialClusterManagerNodes() {
             transportService,
             () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
         transportService.start();
         clusterBootstrapService.onFoundPeersUpdated();
@@ -444,7 +455,9 @@ public void testDoesNotBootstrapsIfNotConfigured() {
             transportService,
             () -> Stream.of(localNode, otherNode1, otherNode2).collect(Collectors.toList()),
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
         transportService.start();
         clusterBootstrapService.scheduleUnconfiguredBootstrap();
@@ -485,7 +498,9 @@ public void testCancelsBootstrapIfRequirementMatchesMultipleNodes() {
             transportService,
             discoveredNodes::get,
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -508,7 +523,9 @@ public void testCancelsBootstrapIfNodeMatchesMultipleRequirements() {
             transportService,
             discoveredNodes::get,
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -594,7 +611,9 @@ public void testDoesNotJustMatchEverything() {
             transportService,
             Collections::emptyList,
             () -> false,
-            vc -> { throw new AssertionError("should not be called"); }
+            vc -> {
+                throw new AssertionError("should not be called");
+            }
         );
 
         transportService.start();
@@ -654,23 +673,6 @@ public void testBootstrapsAutomaticallyWithSingleNodeDiscovery() {
         assertFalse(bootstrapped.get()); // should only bootstrap once
     }
 
-    public void testFailBootstrapWithBothSingleNodeDiscoveryAndInitialMasterNodes() {
-        final Settings.Builder settings = Settings.builder()
-            .put(DiscoveryModule.DISCOVERY_TYPE_SETTING.getKey(), DiscoveryModule.SINGLE_NODE_DISCOVERY_TYPE)
-            .put(NODE_NAME_SETTING.getKey(), localNode.getName())
-            .put(INITIAL_MASTER_NODES_SETTING.getKey(), "test");
-
-        assertThat(
-            expectThrows(
-                IllegalArgumentException.class,
-                () -> new ClusterBootstrapService(settings.build(), transportService, () -> emptyList(), () -> false, vc -> fail())
-            ).getMessage(),
-            containsString(
-                "setting [" + INITIAL_MASTER_NODES_SETTING.getKey() + "] is not allowed when [discovery.type] is set " + "to [single-node]"
-            )
-        );
-    }
-
     /**
      * Validate the correct setting name of cluster.initial_cluster_manager_nodes is shown in the exception,
      * when discovery type is single-node.
@@ -694,18 +696,18 @@ public void testFailBootstrapWithBothSingleNodeDiscoveryAndInitialClusterManager
         );
     }
 
-    public void testFailBootstrapNonMasterEligibleNodeWithSingleNodeDiscovery() {
+    public void testFailBootstrapNonClusterManagerEligibleNodeWithSingleNodeDiscovery() {
         final Settings.Builder settings = Settings.builder()
             .put(DiscoveryModule.DISCOVERY_TYPE_SETTING.getKey(), DiscoveryModule.SINGLE_NODE_DISCOVERY_TYPE)
             .put(NODE_NAME_SETTING.getKey(), localNode.getName())
-            .put(nonMasterNode());
+            .put(nonClusterManagerNode());
 
         assertThat(
             expectThrows(
                 IllegalArgumentException.class,
                 () -> new ClusterBootstrapService(settings.build(), transportService, () -> emptyList(), () -> false, vc -> fail())
             ).getMessage(),
-            containsString("node with [discovery.type] set to [single-node] must be master-eligible")
+            containsString("node with [discovery.type] set to [single-node] must be cluster-manager-eligible")
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelperTests.java b/server/src/test/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelperTests.java
index 13cdc640008cb..1fd9b8b63a08b 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelperTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelperTests.java
@@ -41,13 +41,14 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Collectors;
 
@@ -57,6 +58,7 @@
 import static java.util.Collections.singletonList;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.BOOTSTRAP_PLACEHOLDER_PREFIX;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING;
+import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_MASTER_NODES_SETTING;
 import static org.opensearch.monitor.StatusInfo.Status.HEALTHY;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 import static org.opensearch.node.Node.NODE_NAME_SETTING;
@@ -172,7 +174,7 @@ public void testScheduling() {
         assertThat(logLastFailedJoinAttemptWarningCount.get(), is(5L));
     }
 
-    public void testDescriptionOnMasterIneligibleNodes() {
+    public void testDescriptionOnClusterManagerIneligibleNodes() {
         final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
             .version(12L)
@@ -191,7 +193,7 @@ public void testDescriptionOnMasterIneligibleNodes() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet: have discovered []; discovery will continue using [] from hosts providers "
+                "cluster-manager not discovered yet: have discovered []; discovery will continue using [] from hosts providers "
                     + "and [] from last-known cluster state; node term 15, last-accepted version 12 in term 4"
             )
         );
@@ -208,7 +210,7 @@ public void testDescriptionOnMasterIneligibleNodes() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet: have discovered []; discovery will continue using ["
+                "cluster-manager not discovered yet: have discovered []; discovery will continue using ["
                     + otherAddress
                     + "] from hosts providers and [] from last-known cluster state; node term 16, last-accepted version 12 in term 4"
             )
@@ -226,7 +228,7 @@ public void testDescriptionOnMasterIneligibleNodes() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet: have discovered ["
+                "cluster-manager not discovered yet: have discovered ["
                     + otherNode
                     + "]; discovery will continue using [] from hosts providers "
                     + "and [] from last-known cluster state; node term 17, last-accepted version 12 in term 4"
@@ -257,7 +259,7 @@ public void testDescriptionForBWCState() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet: have discovered []; discovery will continue using [] from hosts providers "
+                "cluster-manager not discovered yet: have discovered []; discovery will continue using [] from hosts providers "
                     + "and [] from last-known cluster state; node term 15, last-accepted version 42 in term 0"
             )
         );
@@ -283,16 +285,16 @@ public void testDescriptionOnUnhealthyNodes() {
             is("this node is unhealthy: unhealthy-info")
         );
 
-        final DiscoveryNode masterNode = new DiscoveryNode(
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(
             "local",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            org.opensearch.common.collect.Set.of(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Set.of(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
             Version.CURRENT
         );
         clusterState = ClusterState.builder(ClusterName.DEFAULT)
             .version(12L)
-            .nodes(DiscoveryNodes.builder().add(masterNode).localNodeId(masterNode.getId()))
+            .nodes(DiscoveryNodes.builder().add(clusterManagerNode).localNodeId(clusterManagerNode.getId()))
             .build();
 
         assertThat(
@@ -328,7 +330,7 @@ public void testDescriptionBeforeBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet, this node has not previously joined a bootstrapped cluster, and "
+                "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and "
                     + "[cluster.initial_cluster_manager_nodes] is empty on this node: have discovered []; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -348,7 +350,7 @@ public void testDescriptionBeforeBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet, this node has not previously joined a bootstrapped cluster, and "
+                "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and "
                     + "[cluster.initial_cluster_manager_nodes] is empty on this node: have discovered []; "
                     + "discovery will continue using ["
                     + otherAddress
@@ -370,7 +372,7 @@ public void testDescriptionBeforeBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet, this node has not previously joined a bootstrapped cluster, and "
+                "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and "
                     + "[cluster.initial_cluster_manager_nodes] is empty on this node: have discovered ["
                     + otherNode
                     + "]; "
@@ -391,8 +393,8 @@ public void testDescriptionBeforeBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet, this node has not previously joined a bootstrapped cluster, and "
-                    + "this node must discover master-eligible nodes [other] to bootstrap a cluster: have discovered []; "
+                "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and "
+                    + "this node must discover cluster-manager-eligible nodes [other] to bootstrap a cluster: have discovered []; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
                     + "] from last-known cluster state; node term 4, last-accepted version 7 in term 4"
@@ -400,6 +402,38 @@ public void testDescriptionBeforeBootstrapping() {
         );
     }
 
+    // Validate the value of the deprecated 'master' setting can be obtained during cluster formation failure.
+    public void testDescriptionBeforeBootstrappingWithDeprecatedMasterNodesSetting() {
+        final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);
+        final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .version(7L)
+            .metadata(Metadata.builder().coordinationMetadata(CoordinationMetadata.builder().term(4L).build()))
+            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()))
+            .build();
+        assertThat(
+            new ClusterFormationState(
+                Settings.builder().putList(INITIAL_MASTER_NODES_SETTING.getKey(), "other").build(),
+                clusterState,
+                emptyList(),
+                emptyList(),
+                4L,
+                electionStrategy,
+                new StatusInfo(HEALTHY, "healthy-info")
+            ).getDescription(),
+            is(
+                "cluster-manager not discovered yet, this node has not previously joined a bootstrapped cluster, and "
+                    + "this node must discover cluster-manager-eligible nodes [other] to bootstrap a cluster: have discovered []; "
+                    + "discovery will continue using [] from hosts providers and ["
+                    + localNode
+                    + "] from last-known cluster state; node term 4, last-accepted version 7 in term 4"
+            )
+        );
+        assertWarnings(
+            "[cluster.initial_master_nodes] setting was deprecated in OpenSearch and will be removed in a future release! "
+                + "See the breaking changes documentation for the next major version."
+        );
+    }
+
     private static VotingConfiguration config(String[] nodeIds) {
         return new VotingConfiguration(Arrays.stream(nodeIds).collect(Collectors.toSet()));
     }
@@ -428,7 +462,7 @@ public void testDescriptionAfterDetachCluster() {
 
         final ClusterState clusterState = state(
             localNode,
-            VotingConfiguration.MUST_JOIN_ELECTED_MASTER.getNodeIds().toArray(new String[0])
+            VotingConfiguration.MUST_JOIN_ELECTED_CLUSTER_MANAGER.getNodeIds().toArray(new String[0])
         );
 
         assertThat(
@@ -442,7 +476,7 @@ public void testDescriptionAfterDetachCluster() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet and this node was detached from its previous cluster, "
+                "cluster-manager not discovered yet and this node was detached from its previous cluster, "
                     + "have discovered []; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -462,7 +496,7 @@ public void testDescriptionAfterDetachCluster() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet and this node was detached from its previous cluster, "
+                "cluster-manager not discovered yet and this node was detached from its previous cluster, "
                     + "have discovered []; "
                     + "discovery will continue using ["
                     + otherAddress
@@ -484,7 +518,7 @@ public void testDescriptionAfterDetachCluster() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet and this node was detached from its previous cluster, "
+                "cluster-manager not discovered yet and this node was detached from its previous cluster, "
                     + "have discovered ["
                     + otherNode
                     + "]; "
@@ -506,7 +540,7 @@ public void testDescriptionAfterDetachCluster() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered yet and this node was detached from its previous cluster, "
+                "cluster-manager not discovered yet and this node was detached from its previous cluster, "
                     + "have discovered ["
                     + yetAnotherNode
                     + "]; "
@@ -534,7 +568,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [otherNode], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [otherNode], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -554,7 +588,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [otherNode], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [otherNode], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using ["
                     + otherAddress
@@ -576,7 +610,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [otherNode], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [otherNode], "
                     + "have discovered ["
                     + otherNode
                     + "] which is a quorum; "
@@ -598,7 +632,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [otherNode], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [otherNode], "
                     + "have discovered ["
                     + yetAnotherNode
                     + "] which is not a quorum; "
@@ -619,7 +653,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
+                "cluster-manager not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -638,7 +672,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires at least 2 nodes with ids from [n1, n2, n3], "
+                "cluster-manager not discovered or elected yet, an election requires at least 2 nodes with ids from [n1, n2, n3], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -657,7 +691,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires 2 nodes with ids [n1, n2], "
+                "cluster-manager not discovered or elected yet, an election requires 2 nodes with ids [n1, n2], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -676,7 +710,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4], "
+                "cluster-manager not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -695,7 +729,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4, n5], "
+                "cluster-manager not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4, n5], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -714,7 +748,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4], "
+                "cluster-manager not discovered or elected yet, an election requires at least 3 nodes with ids from [n1, n2, n3, n4], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -733,7 +767,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires 3 nodes with ids [n1, n2, n3], "
+                "cluster-manager not discovered or elected yet, an election requires 3 nodes with ids [n1, n2, n3], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -752,7 +786,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [n1], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [n1], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -771,7 +805,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [n1] and a node with id [n2], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [n1] and a node with id [n2], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -790,7 +824,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [n1] and two nodes with ids [n2, n3], "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [n1] and two nodes with ids [n2, n3], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -809,7 +843,7 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires a node with id [n1] and "
+                "cluster-manager not discovered or elected yet, an election requires a node with id [n1] and "
                     + "at least 2 nodes with ids from [n2, n3, n4], "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
@@ -818,9 +852,13 @@ public void testDescriptionAfterBootstrapping() {
             )
         );
 
-        final DiscoveryNode otherMasterNode = new DiscoveryNode("other-master", buildNewFakeTransportAddress(), Version.CURRENT);
-        final DiscoveryNode otherNonMasterNode = new DiscoveryNode(
-            "other-non-master",
+        final DiscoveryNode otherClusterManagerNode = new DiscoveryNode(
+            "other-cluster-manager",
+            buildNewFakeTransportAddress(),
+            Version.CURRENT
+        );
+        final DiscoveryNode otherNonClusterManagerNode = new DiscoveryNode(
+            "other-non-cluster-manager",
             buildNewFakeTransportAddress(),
             emptyMap(),
             new HashSet<>(
@@ -833,7 +871,13 @@ public void testDescriptionAfterBootstrapping() {
 
         String[] configNodeIds = new String[] { "n1", "n2" };
         final ClusterState stateWithOtherNodes = ClusterState.builder(ClusterName.DEFAULT)
-            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).add(otherMasterNode).add(otherNonMasterNode))
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(localNode)
+                    .localNodeId(localNode.getId())
+                    .add(otherClusterManagerNode)
+                    .add(otherNonClusterManagerNode)
+            )
             .metadata(
                 Metadata.builder()
                     .coordinationMetadata(
@@ -859,18 +903,18 @@ public void testDescriptionAfterBootstrapping() {
             // nodes from last-known cluster state could be in either order
             is(
                 oneOf(
-                    "master not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
+                    "cluster-manager not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
                         + "have discovered [] which is not a quorum; "
                         + "discovery will continue using [] from hosts providers and ["
                         + localNode
                         + ", "
-                        + otherMasterNode
+                        + otherClusterManagerNode
                         + "] from last-known cluster state; node term 0, last-accepted version 0 in term 0",
 
-                    "master not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
+                    "cluster-manager not discovered or elected yet, an election requires two nodes with ids [n1, n2], "
                         + "have discovered [] which is not a quorum; "
                         + "discovery will continue using [] from hosts providers and ["
-                        + otherMasterNode
+                        + otherClusterManagerNode
                         + ", "
                         + localNode
                         + "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"
@@ -889,8 +933,8 @@ public void testDescriptionAfterBootstrapping() {
                 new StatusInfo(HEALTHY, "healthy-info")
             ).getDescription(),
             is(
-                "master not discovered or elected yet, an election requires one or more nodes that have already participated as "
-                    + "master-eligible nodes in the cluster but this node was not master-eligible the last time it joined the cluster, "
+                "cluster-manager not discovered or elected yet, an election requires one or more nodes that have already participated as "
+                    + "cluster-manager-eligible nodes in the cluster but this node was not cluster-manager-eligible the last time it joined the cluster, "
                     + "have discovered [] which is not a quorum; "
                     + "discovery will continue using [] from hosts providers and ["
                     + localNode
@@ -899,4 +943,35 @@ public void testDescriptionAfterBootstrapping() {
         );
 
     }
+
+    /*
+     * Validate the Cluster State with deprecated VotingConfiguration.MUST_JOIN_ELECTED_MASTER can get correct ClusterFormationState description.
+     */
+    public void testDescriptionAfterDetachClusterWithDeprecatedMasterVotingConfiguration() {
+        final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);
+
+        final ClusterState clusterState = state(
+            localNode,
+            VotingConfiguration.MUST_JOIN_ELECTED_MASTER.getNodeIds().toArray(new String[0])
+        );
+
+        assertThat(
+            new ClusterFormationState(
+                Settings.EMPTY,
+                clusterState,
+                emptyList(),
+                emptyList(),
+                0L,
+                electionStrategy,
+                new StatusInfo(HEALTHY, "healthy-info")
+            ).getDescription(),
+            is(
+                "cluster-manager not discovered yet and this node was detached from its previous cluster, "
+                    + "have discovered []; "
+                    + "discovery will continue using [] from hosts providers and ["
+                    + localNode
+                    + "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"
+            )
+        );
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/CompressedStreamUtilsTests.java b/server/src/test/java/org/opensearch/cluster/coordination/CompressedStreamUtilsTests.java
new file mode 100644
index 0000000000000..c2843704e0ac5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/coordination/CompressedStreamUtilsTests.java
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.BytesTransportRequest;
+
+import java.io.IOException;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Contains tests for {@link CompressedStreamUtils}
+ */
+public class CompressedStreamUtilsTests extends OpenSearchTestCase {
+
+    public void testCreateCompressedStream() throws IOException {
+        // serialization success with normal state
+        final ClusterState localClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(Metadata.builder().generateClusterUuidIfNeeded().clusterUUIDCommitted(true))
+            .build();
+        DiscoveryNode localNode = new DiscoveryNode("node0", buildNewFakeTransportAddress(), Version.CURRENT);
+        BytesReference bytes = CompressedStreamUtils.createCompressedStream(localNode.getVersion(), localClusterState::writeTo);
+        assertNotNull(bytes);
+
+        // Fail on write failure on mocked cluster state's writeTo exception
+        ClusterState mockedState = mock(ClusterState.class);
+        doThrow(IOException.class).when(mockedState).writeTo(any());
+        assertThrows(IOException.class, () -> CompressedStreamUtils.createCompressedStream(localNode.getVersion(), mockedState::writeTo));
+    }
+
+    public void testDecompressBytes() throws IOException {
+        // Decompression works fine
+        final ClusterState localClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(Metadata.builder().generateClusterUuidIfNeeded().clusterUUIDCommitted(true))
+            .build();
+        DiscoveryNode localNode = new DiscoveryNode("node0", buildNewFakeTransportAddress(), Version.CURRENT);
+        BytesReference bytes = CompressedStreamUtils.createCompressedStream(localNode.getVersion(), localClusterState::writeTo);
+        BytesTransportRequest request = new BytesTransportRequest(bytes, localNode.getVersion());
+        StreamInput input = CompressedStreamUtils.decompressBytes(request, DEFAULT_NAMED_WRITABLE_REGISTRY);
+        assertEquals(request.version(), input.getVersion());
+
+        // Decompression fails with AssertionError on non-compressed request
+        BytesTransportRequest mockedRequest = mock(BytesTransportRequest.class, RETURNS_DEEP_STUBS);
+        when(mockedRequest.bytes().streamInput()).thenThrow(IOException.class);
+        assertThrows(AssertionError.class, () -> CompressedStreamUtils.decompressBytes(mockedRequest, DEFAULT_NAMED_WRITABLE_REGISTRY));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/CoordinationMetadataTests.java b/server/src/test/java/org/opensearch/cluster/coordination/CoordinationMetadataTests.java
index 1b5de242507d2..290479941aaa9 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/CoordinationMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/CoordinationMetadataTests.java
@@ -33,16 +33,16 @@
 
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/CoordinationStateTests.java b/server/src/test/java/org/opensearch/cluster/coordination/CoordinationStateTests.java
index 6ddbc909747f7..f37823d2c0c7d 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/CoordinationStateTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/CoordinationStateTests.java
@@ -31,32 +31,49 @@
 
 package org.opensearch.cluster.coordination;
 
-import org.opensearch.Assertions;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
 import org.opensearch.cluster.coordination.CoordinationState.PersistedState;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.gateway.GatewayMetaState.RemotePersistedState;
+import org.opensearch.gateway.remote.ClusterMetadataManifest;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
+import java.io.IOException;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 public class CoordinationStateTests extends OpenSearchTestCase {
 
@@ -67,6 +84,7 @@ public class CoordinationStateTests extends OpenSearchTestCase {
     private ClusterState initialStateNode1;
 
     private PersistedState ps1;
+    private PersistedStateRegistry psr1;
 
     private CoordinationState cs1;
     private CoordinationState cs2;
@@ -97,10 +115,12 @@ public void setupNodes() {
         );
 
         ps1 = new InMemoryPersistedState(0L, initialStateNode1);
+        psr1 = persistedStateRegistry();
+        psr1.addPersistedState(PersistedStateType.LOCAL, ps1);
 
-        cs1 = createCoordinationState(ps1, node1);
-        cs2 = createCoordinationState(new InMemoryPersistedState(0L, initialStateNode2), node2);
-        cs3 = createCoordinationState(new InMemoryPersistedState(0L, initialStateNode3), node3);
+        cs1 = createCoordinationState(psr1, node1, Settings.EMPTY);
+        cs2 = createCoordinationState(createPersistedStateRegistry(initialStateNode2), node2, Settings.EMPTY);
+        cs3 = createCoordinationState(createPersistedStateRegistry(initialStateNode3), node3, Settings.EMPTY);
     }
 
     public static DiscoveryNode createNode(String id) {
@@ -200,7 +220,7 @@ public void testJoinBeforeBootstrap() {
     public void testJoinWithNoStartJoinAfterReboot() {
         StartJoinRequest startJoinRequest1 = new StartJoinRequest(node1, randomLongBetween(1, 5));
         Join v1 = cs1.handleStartJoin(startJoinRequest1);
-        cs1 = createCoordinationState(ps1, node1);
+        cs1 = createCoordinationState(psr1, node1, Settings.EMPTY);
         assertThat(
             expectThrows(CoordinationStateRejectedException.class, () -> cs1.handleJoin(v1)).getMessage(),
             containsString("ignored join as term has not been incremented yet after reboot")
@@ -586,7 +606,7 @@ public void testHandlePublishRequestWithBadTerm() {
         );
     }
 
-    // scenario when handling a publish request from a master that we already received a newer state from
+    // scenario when handling a publish request from a cluster-manager that we already received a newer state from
     public void testHandlePublishRequestWithSameTermButOlderOrSameVersion() {
         VotingConfiguration initialConfig = VotingConfiguration.of(node1);
         ClusterState state1 = clusterState(0L, 0L, node1, initialConfig, initialConfig, 42L);
@@ -613,7 +633,7 @@ public void testHandlePublishRequestWithSameTermButOlderOrSameVersion() {
         );
     }
 
-    // scenario when handling a publish request from a fresh master
+    // scenario when handling a publish request from a fresh cluster-manager
     public void testHandlePublishRequestWithTermHigherThanLastAcceptedTerm() {
         VotingConfiguration initialConfig = VotingConfiguration.of(node1);
         StartJoinRequest startJoinRequest1 = new StartJoinRequest(node1, randomLongBetween(1, 5));
@@ -845,7 +865,7 @@ public void testVoteCollection() {
 
         assertFalse(
             voteCollection.addVote(
-                new DiscoveryNode("master-ineligible", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT)
+                new DiscoveryNode("cluster-manager-ineligible", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT)
             )
         );
         assertTrue(voteCollection.isEmpty());
@@ -886,8 +906,102 @@ public void testSafety() {
         ).runRandomly();
     }
 
-    public static CoordinationState createCoordinationState(PersistedState storage, DiscoveryNode localNode) {
-        return new CoordinationState(localNode, storage, ElectionStrategy.DEFAULT_INSTANCE);
+    public void testHandlePrePublishAndCommitWhenRemoteStateDisabled() {
+        final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+        persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, ps1);
+        final PersistedStateRegistry persistedStateRegistrySpy = Mockito.spy(persistedStateRegistry);
+        final CoordinationState coordinationState = createCoordinationState(persistedStateRegistrySpy, node1, Settings.EMPTY);
+        final VotingConfiguration initialConfig = VotingConfiguration.of(node1);
+        final ClusterState clusterState = clusterState(0L, 0L, node1, initialConfig, initialConfig, 42L);
+        coordinationState.handlePrePublish(clusterState);
+        Mockito.verify(persistedStateRegistrySpy, Mockito.times(0)).getPersistedState(PersistedStateType.REMOTE);
+        assertThat(persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE), nullValue());
+        final ClusterState clusterState2 = clusterState(0L, 1L, node1, initialConfig, initialConfig, 42L);
+        coordinationState.handlePrePublish(clusterState2);
+        Mockito.verify(persistedStateRegistrySpy, Mockito.times(0)).getPersistedState(PersistedStateType.REMOTE);
+        assertThat(persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE), nullValue());
+        coordinationState.handlePreCommit();
+        Mockito.verify(persistedStateRegistrySpy, Mockito.times(0)).getPersistedState(PersistedStateType.REMOTE);
+        assertThat(persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE), nullValue());
+    }
+
+    public void testHandlePrePublishAndCommitWhenRemoteStateEnabled() throws IOException {
+        final RemoteClusterStateService remoteClusterStateService = Mockito.mock(RemoteClusterStateService.class);
+        final VotingConfiguration initialConfig = VotingConfiguration.of(node1);
+        final ClusterState clusterState = clusterState(0L, 0L, node1, initialConfig, initialConfig, 42L);
+        final String previousClusterUUID = "prev-cluster-uuid";
+        final ClusterMetadataManifest manifest = new ClusterMetadataManifest(
+            0L,
+            0L,
+            randomAlphaOfLength(10),
+            randomAlphaOfLength(10),
+            Version.CURRENT,
+            randomAlphaOfLength(10),
+            false,
+            Collections.emptyList(),
+            randomAlphaOfLength(10),
+            true
+        );
+        Mockito.when(remoteClusterStateService.writeFullMetadata(clusterState, previousClusterUUID)).thenReturn(manifest);
+
+        final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+        persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, ps1);
+        persistedStateRegistry.addPersistedState(
+            PersistedStateType.REMOTE,
+            new RemotePersistedState(remoteClusterStateService, previousClusterUUID)
+        );
+
+        String randomRepoName = "randomRepoName";
+        String stateRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            randomRepoName
+        );
+        String stateRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            randomRepoName
+        );
+
+        Settings settings = Settings.builder()
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, randomRepoName)
+            .put(stateRepoTypeAttributeKey, FsRepository.TYPE)
+            .put(stateRepoSettingsAttributeKeyPrefix + "location", "randomRepoPath")
+            .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true)
+            .build();
+
+        final CoordinationState coordinationState = createCoordinationState(persistedStateRegistry, node1, settings);
+        coordinationState.handlePrePublish(clusterState);
+        Mockito.verify(remoteClusterStateService, Mockito.times(1)).writeFullMetadata(clusterState, previousClusterUUID);
+        assertThat(persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE).getLastAcceptedState(), equalTo(clusterState));
+
+        coordinationState.handlePreCommit();
+        ClusterState committedClusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder(clusterState.metadata()).clusterUUIDCommitted(true).build())
+            .build();
+        // Mockito.verify(remoteClusterStateService, Mockito.times(1)).markLastStateAsCommitted(committedClusterState, manifest);
+        ArgumentCaptor<ClusterState> clusterStateCaptor = ArgumentCaptor.forClass(ClusterState.class);
+        verify(remoteClusterStateService, times(1)).markLastStateAsCommitted(clusterStateCaptor.capture(), any());
+        assertThat(clusterStateCaptor.getValue().metadata().indices(), equalTo(committedClusterState.metadata().indices()));
+        assertThat(clusterStateCaptor.getValue().metadata().clusterUUID(), equalTo(committedClusterState.metadata().clusterUUID()));
+        assertThat(clusterStateCaptor.getValue().stateUUID(), equalTo(committedClusterState.stateUUID()));
+        assertThat(
+            clusterStateCaptor.getValue().coordinationMetadata().term(),
+            equalTo(committedClusterState.coordinationMetadata().term())
+        );
+        assertThat(clusterStateCaptor.getValue().version(), equalTo(committedClusterState.version()));
+        assertThat(
+            clusterStateCaptor.getValue().metadata().clusterUUIDCommitted(),
+            equalTo(committedClusterState.metadata().clusterUUIDCommitted())
+        );
+    }
+
+    public static CoordinationState createCoordinationState(
+        PersistedStateRegistry persistedStateRegistry,
+        DiscoveryNode localNode,
+        Settings settings
+    ) {
+        return new CoordinationState(localNode, persistedStateRegistry, ElectionStrategy.DEFAULT_INSTANCE, settings);
     }
 
     public static ClusterState clusterState(
@@ -950,4 +1064,10 @@ public static ClusterState setValue(ClusterState clusterState, long value) {
     public static long value(ClusterState clusterState) {
         return clusterState.metadata().persistentSettings().getAsLong("value", 0L);
     }
+
+    private static PersistedStateRegistry createPersistedStateRegistry(ClusterState clusterState) {
+        final PersistedStateRegistry persistedStateRegistry = new PersistedStateRegistry();
+        persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, new InMemoryPersistedState(0L, clusterState));
+        return persistedStateRegistry;
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/CoordinatorTests.java b/server/src/test/java/org/opensearch/cluster/coordination/CoordinatorTests.java
index 1cdea588564c4..a3129655148ab 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/CoordinatorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/CoordinatorTests.java
@@ -46,13 +46,13 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.monitor.StatusInfo;
@@ -73,8 +73,8 @@
 import static java.util.Collections.singleton;
 import static org.opensearch.cluster.coordination.AbstractCoordinatorTestCase.Cluster.DEFAULT_DELAY_VARIABILITY;
 import static org.opensearch.cluster.coordination.AbstractCoordinatorTestCase.Cluster.EXTREME_DELAY_VARIABILITY;
-import static org.opensearch.cluster.coordination.Coordinator.PUBLISH_TIMEOUT_SETTING;
 import static org.opensearch.cluster.coordination.Coordinator.Mode.CANDIDATE;
+import static org.opensearch.cluster.coordination.Coordinator.PUBLISH_TIMEOUT_SETTING;
 import static org.opensearch.cluster.coordination.ElectionSchedulerFactory.ELECTION_INITIAL_TIMEOUT_SETTING;
 import static org.opensearch.cluster.coordination.FollowersChecker.FOLLOWER_CHECK_INTERVAL_SETTING;
 import static org.opensearch.cluster.coordination.FollowersChecker.FOLLOWER_CHECK_RETRY_COUNT_SETTING;
@@ -82,15 +82,16 @@
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_INTERVAL_SETTING;
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING;
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_ALL;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_METADATA_WRITES;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_WRITES;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES;
 import static org.opensearch.cluster.coordination.Reconfigurator.CLUSTER_AUTO_SHRINK_VOTING_CONFIGURATION;
+import static org.opensearch.discovery.PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_DURING_DECOMMISSION_SETTING;
 import static org.opensearch.discovery.PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_SETTING;
 import static org.opensearch.monitor.StatusInfo.Status.HEALTHY;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
@@ -107,9 +108,9 @@
 public class CoordinatorTests extends AbstractCoordinatorTestCase {
 
     /**
-     * This test was added to verify that state recovery is properly reset on a node after it has become master and successfully
+     * This test was added to verify that state recovery is properly reset on a node after it has become cluster-manager and successfully
      * recovered a state (see {@link GatewayService}). The situation which triggers this with a decent likelihood is as follows:
-     * 3 master-eligible nodes (leader, follower1, follower2), the followers are shut down (leader remains), when followers come back
+     * 3 cluster-manager-eligible nodes (leader, follower1, follower2), the followers are shut down (leader remains), when followers come back
      * one of them becomes leader and publishes first state (with STATE_NOT_RECOVERED_BLOCK) to old leader, which accepts it.
      * Old leader is initiating an election at the same time, and wins election. It becomes leader again, but as it previously
      * successfully completed state recovery, is never reset to a state where state recovery can be retried.
@@ -164,13 +165,13 @@ public void testCanUpdateClusterStateAfterStabilisation() {
         }
     }
 
-    public void testDoesNotElectNonMasterNode() {
+    public void testDoesNotElectNonClusterManagerNode() {
         try (Cluster cluster = new Cluster(randomIntBetween(1, 5), false, Settings.EMPTY)) {
             cluster.runRandomly();
             cluster.stabilise();
 
             final ClusterNode leader = cluster.getAnyLeader();
-            assertTrue(leader.getLocalNode().isMasterNode());
+            assertTrue(leader.getLocalNode().isClusterManagerNode());
         }
     }
 
@@ -191,7 +192,7 @@ public void testUnhealthyNodesGetsRemoved() {
             cluster.clusterNodes.add(newNode1);
             cluster.clusterNodes.add(newNode2);
             cluster.stabilise(
-                // The first pinging discovers the master
+                // The first pinging discovers the cluster-manager
                 defaultMillis(DISCOVERY_FIND_PEERS_INTERVAL_SETTING)
                     // One message delay to send a join
                     + DEFAULT_DELAY_VARIABILITY
@@ -627,7 +628,7 @@ public void testUnHealthyLeaderRemoved() {
             cluster.clusterNodes.add(newNode2);
             cluster.clusterNodes.add(newNode3);
             cluster.stabilise(
-                // The first pinging discovers the master
+                // The first pinging discovers the cluster-manager
                 defaultMillis(DISCOVERY_FIND_PEERS_INTERVAL_SETTING)
                     // One message delay to send a join
                     + DEFAULT_DELAY_VARIABILITY
@@ -1096,7 +1097,7 @@ public void testIncompatibleDiffResendsFullState() {
      * does not notice the node disconnecting, it is important for the node not to be turned back into a follower but try
      * and join the leader again.
      */
-    public void testStayCandidateAfterReceivingFollowerCheckFromKnownMaster() {
+    public void testStayCandidateAfterReceivingFollowerCheckFromKnownClusterManager() {
         try (Cluster cluster = new Cluster(2, false, Settings.EMPTY)) {
             cluster.runRandomly();
             cluster.stabilise();
@@ -1121,23 +1122,23 @@ public void testStayCandidateAfterReceivingFollowerCheckFromKnownMaster() {
         }
     }
 
-    public void testAppliesNoMasterBlockWritesByDefault() {
-        testAppliesNoMasterBlock(null, NO_MASTER_BLOCK_WRITES);
+    public void testAppliesNoClusterManagerBlockWritesByDefault() {
+        testAppliesNoClusterManagerBlock(null, NO_CLUSTER_MANAGER_BLOCK_WRITES);
     }
 
-    public void testAppliesNoMasterBlockWritesIfConfigured() {
-        testAppliesNoMasterBlock("write", NO_MASTER_BLOCK_WRITES);
+    public void testAppliesNoClusterManagerBlockWritesIfConfigured() {
+        testAppliesNoClusterManagerBlock("write", NO_CLUSTER_MANAGER_BLOCK_WRITES);
     }
 
-    public void testAppliesNoMasterBlockAllIfConfigured() {
-        testAppliesNoMasterBlock("all", NO_MASTER_BLOCK_ALL);
+    public void testAppliesNoClusterManagerBlockAllIfConfigured() {
+        testAppliesNoClusterManagerBlock("all", NO_CLUSTER_MANAGER_BLOCK_ALL);
     }
 
-    public void testAppliesNoMasterBlockMetadataWritesIfConfigured() {
-        testAppliesNoMasterBlock("metadata_write", NO_MASTER_BLOCK_METADATA_WRITES);
+    public void testAppliesNoClusterManagerBlockMetadataWritesIfConfigured() {
+        testAppliesNoClusterManagerBlock("metadata_write", NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES);
     }
 
-    private void testAppliesNoMasterBlock(String noMasterBlockSetting, ClusterBlock expectedBlock) {
+    private void testAppliesNoClusterManagerBlock(String noClusterManagerBlockSetting, ClusterBlock expectedBlock) {
         try (Cluster cluster = new Cluster(3)) {
             cluster.runRandomly();
             cluster.stabilise();
@@ -1145,7 +1146,7 @@ private void testAppliesNoMasterBlock(String noMasterBlockSetting, ClusterBlock
             final ClusterNode leader = cluster.getAnyLeader();
             leader.submitUpdateTask("update NO_CLUSTER_MANAGER_BLOCK_SETTING", cs -> {
                 final Builder settingsBuilder = Settings.builder().put(cs.metadata().persistentSettings());
-                settingsBuilder.put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), noMasterBlockSetting);
+                settingsBuilder.put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), noClusterManagerBlockSetting);
                 return ClusterState.builder(cs)
                     .metadata(Metadata.builder(cs.metadata()).persistentSettings(settingsBuilder.build()))
                     .build();
@@ -1175,12 +1176,12 @@ private void testAppliesNoMasterBlock(String noMasterBlockSetting, ClusterBlock
         }
     }
 
-    public void testNodeCannotJoinIfJoinValidationFailsOnMaster() {
+    public void testNodeCannotJoinIfJoinValidationFailsOnClusterManager() {
         try (Cluster cluster = new Cluster(randomIntBetween(1, 3))) {
             cluster.runRandomly();
             cluster.stabilise();
 
-            // check that if node join validation fails on master, the nodes can't join
+            // check that if node join validation fails on cluster-manager, the nodes can't join
             List<ClusterNode> addedNodes = cluster.addNodes(randomIntBetween(1, 2));
             final Set<DiscoveryNode> validatedNodes = new HashSet<>();
             cluster.getAnyLeader().extraJoinValidators.add((discoveryNode, clusterState) -> {
@@ -1231,11 +1232,9 @@ public void testClusterCannotFormWithFailingJoinValidation() {
                     nodes.stream().map(ClusterNode::getLocalNode).map(DiscoveryNode::getId).collect(Collectors.toSet())
                 ) == false,
                 () -> randomSubsetOf(cluster.clusterNodes)
-            ).forEach(
-                cn -> cn.extraJoinValidators.add(
-                    (discoveryNode, clusterState) -> { throw new IllegalArgumentException("join validation failed"); }
-                )
-            );
+            ).forEach(cn -> cn.extraJoinValidators.add((discoveryNode, clusterState) -> {
+                throw new IllegalArgumentException("join validation failed");
+            }));
             cluster.bootstrapIfNecessary();
             cluster.runFor(10000, "failing join validation");
             assertTrue(cluster.clusterNodes.stream().allMatch(cn -> cn.getLastAppliedClusterState().version() == 0));
@@ -1257,7 +1256,7 @@ public void testCannotJoinClusterWithDifferentUUID() throws IllegalAccessExcepti
 
             final ClusterNode newNode = cluster1.new ClusterNode(
                 nextNodeIndex.getAndIncrement(), nodeInOtherCluster.getLocalNode(), n -> cluster1.new MockPersistedState(
-                    n, nodeInOtherCluster.persistedState, Function.identity(), Function.identity()
+                    n, nodeInOtherCluster.persistedStateRegistry, Function.identity(), Function.identity()
                 ), nodeInOtherCluster.nodeSettings, () -> new StatusInfo(StatusInfo.Status.HEALTHY, "healthy-info")
             );
 
@@ -1305,7 +1304,7 @@ public void testDiscoveryUsesNodesFromLastClusterState() {
         }
     }
 
-    public void testFollowerRemovedIfUnableToSendRequestsToMaster() {
+    public void testFollowerRemovedIfUnableToSendRequestsToClusterManager() {
         try (Cluster cluster = new Cluster(3)) {
             cluster.runRandomly();
             cluster.stabilise();
@@ -1333,7 +1332,7 @@ public void testFollowerRemovedIfUnableToSendRequestsToMaster() {
             cluster.clearBlackholedConnections();
 
             cluster.stabilise(
-                // time for the disconnected node to find the master again
+                // time for the disconnected node to find the cluster-manager again
                 defaultMillis(DISCOVERY_FIND_PEERS_INTERVAL_SETTING) * 2
                     // time for joining
                     + 4 * DEFAULT_DELAY_VARIABILITY
@@ -1558,7 +1557,9 @@ public void match(LogEvent event) {
                             final String message = event.getMessage().getFormattedMessage();
                             assertThat(
                                 message,
-                                startsWith("master not discovered or elected yet, an election requires at least 2 nodes with ids from [")
+                                startsWith(
+                                    "cluster-manager not discovered or elected yet, an election requires at least 2 nodes with ids from ["
+                                )
                             );
 
                             final List<ClusterNode> matchingNodes = cluster.clusterNodes.stream()
@@ -1677,7 +1678,7 @@ public String toString() {
         }
     }
 
-    public void testReconfiguresToExcludeMasterIneligibleNodesInVotingConfig() {
+    public void testReconfiguresToExcludeClusterManagerIneligibleNodesInVotingConfig() {
         try (Cluster cluster = new Cluster(3)) {
             cluster.runRandomly();
             cluster.stabilise();
@@ -1696,11 +1697,11 @@ public void testReconfiguresToExcludeMasterIneligibleNodesInVotingConfig() {
             final boolean chosenNodeIsLeader = chosenNode == cluster.getAnyLeader();
             final long termBeforeRestart = cluster.getAnyNode().coordinator.getCurrentTerm();
 
-            logger.info("--> restarting [{}] as a master-ineligible node", chosenNode);
+            logger.info("--> restarting [{}] as a cluster-manager-ineligible node", chosenNode);
 
             chosenNode.close();
             cluster.clusterNodes.replaceAll(
-                cn -> cn == chosenNode ? cn.restartedNode(Function.identity(), Function.identity(), nonMasterNode()) : cn
+                cn -> cn == chosenNode ? cn.restartedNode(Function.identity(), Function.identity(), nonClusterManagerNode()) : cn
             );
             cluster.stabilise();
 
@@ -1727,9 +1728,9 @@ public void testDoesNotPerformElectionWhenRestartingFollower() {
             final ClusterNode leader = cluster.getAnyLeader();
             final long expectedTerm = leader.coordinator.getCurrentTerm();
 
-            if (cluster.clusterNodes.stream().filter(n -> n.getLocalNode().isMasterNode()).count() == 2) {
+            if (cluster.clusterNodes.stream().filter(n -> n.getLocalNode().isClusterManagerNode()).count() == 2) {
                 // in the 2-node case, auto-shrinking the voting configuration is required to reduce the voting configuration down to just
-                // the leader, otherwise restarting the other master-eligible node triggers an election
+                // the leader, otherwise restarting the other cluster-manager-eligible node triggers an election
                 leader.submitSetAutoShrinkVotingConfiguration(true);
                 cluster.stabilise(2 * DEFAULT_CLUSTER_STATE_UPDATE_DELAY); // 1st delay for the setting update, 2nd for the reconfiguration
             }
@@ -1778,6 +1779,48 @@ public void testImproveConfigurationPerformsVotingConfigExclusionStateCheck() {
         }
     }
 
+    public void testLocalNodeAlwaysCommissionedWithoutDecommissionedException() {
+        try (Cluster cluster = new Cluster(randomIntBetween(1, 5))) {
+            cluster.runRandomly();
+            cluster.stabilise();
+            for (ClusterNode node : cluster.clusterNodes) {
+                assertTrue(node.coordinator.localNodeCommissioned());
+            }
+        }
+    }
+
+    public void testClusterStabilisesForPreviouslyDecommissionedNode() {
+        try (Cluster cluster = new Cluster(randomIntBetween(1, 5))) {
+            cluster.runRandomly();
+            cluster.stabilise();
+            for (ClusterNode node : cluster.clusterNodes) {
+                assertTrue(node.coordinator.localNodeCommissioned());
+            }
+            final ClusterNode leader = cluster.getAnyLeader();
+
+            ClusterNode decommissionedNode = cluster.new ClusterNode(
+                nextNodeIndex.getAndIncrement(), true, leader.nodeSettings, () -> new StatusInfo(HEALTHY, "healthy-info")
+            );
+            decommissionedNode.coordinator.onNodeCommissionStatusChange(false);
+            cluster.clusterNodes.add(decommissionedNode);
+
+            assertFalse(decommissionedNode.coordinator.localNodeCommissioned());
+
+            cluster.stabilise(
+                // Interval is updated to decommissioned find peer interval
+                defaultMillis(DISCOVERY_FIND_PEERS_INTERVAL_DURING_DECOMMISSION_SETTING)
+                    // One message delay to send a join
+                    + DEFAULT_DELAY_VARIABILITY
+                    // Commit a new cluster state with the new node(s). Might be split into multiple commits, and each might need a
+                    // followup reconfiguration
+                    + 3 * 2 * DEFAULT_CLUSTER_STATE_UPDATE_DELAY
+            );
+
+            // once cluster stabilises the node joins and would be commissioned
+            assertTrue(decommissionedNode.coordinator.localNodeCommissioned());
+        }
+    }
+
     private ClusterState buildNewClusterStateWithVotingConfigExclusion(
         ClusterState currentState,
         Set<CoordinationMetadata.VotingConfigExclusion> newVotingConfigExclusion
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/FollowersCheckerTests.java b/server/src/test/java/org/opensearch/cluster/coordination/FollowersCheckerTests.java
index 7e7193fbf02ef..c152a1606681e 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/FollowersCheckerTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/FollowersCheckerTests.java
@@ -39,22 +39,23 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -123,7 +124,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -132,7 +134,9 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             settings,
             transportService,
             fcr -> { assert false : fcr; },
-            (node, reason) -> { assert false : node; },
+            (node, reason) -> {
+                assert false : node;
+            },
             () -> new StatusInfo(StatusInfo.Status.HEALTHY, "healthy-info")
         );
 
@@ -283,7 +287,8 @@ public String toString() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -369,7 +374,8 @@ public String toString() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -473,7 +479,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> follower,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -544,7 +551,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> follower,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -685,7 +693,7 @@ public String executor() {
         }
     }
 
-    public void testPreferMasterNodes() {
+    public void testPreferClusterManagerNodes() {
         List<DiscoveryNode> nodes = randomNodes(10);
         DiscoveryNodes.Builder discoNodesBuilder = DiscoveryNodes.builder();
         nodes.forEach(dn -> discoNodesBuilder.add(dn));
@@ -699,13 +707,16 @@ public void testPreferMasterNodes() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> nodes.get(0),
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         final FollowersChecker followersChecker = new FollowersChecker(
             Settings.EMPTY,
             transportService,
             fcr -> { assert false : fcr; },
-            (node, reason) -> { assert false : node; },
+            (node, reason) -> {
+                assert false : node;
+            },
             () -> new StatusInfo(HEALTHY, "healthy-info")
         );
         followersChecker.setCurrentNodes(discoveryNodes);
@@ -713,7 +724,7 @@ public void testPreferMasterNodes() {
             .map(cr -> cr.node)
             .collect(Collectors.toList());
         List<DiscoveryNode> sortedFollowerTargets = new ArrayList<>(followerTargets);
-        Collections.sort(sortedFollowerTargets, Comparator.comparing(n -> n.isMasterNode() == false));
+        Collections.sort(sortedFollowerTargets, Comparator.comparing(n -> n.isClusterManagerNode() == false));
         assertEquals(sortedFollowerTargets, followerTargets);
     }
 
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/JoinHelperTests.java b/server/src/test/java/org/opensearch/cluster/coordination/JoinHelperTests.java
index b53cf9ddf1dd2..78c3b5d45a9ab 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/JoinHelperTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/JoinHelperTests.java
@@ -37,32 +37,52 @@
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.NotMasterException;
+import org.opensearch.cluster.NotClusterManagerException;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.monitor.StatusInfo;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.test.transport.CapturingTransport.CapturedRequest;
 import org.opensearch.test.transport.MockTransport;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.BytesTransportRequest;
 import org.opensearch.transport.RemoteTransportException;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportService;
 
+import java.io.IOException;
 import java.util.Collections;
 import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicReference;
 
+import static org.opensearch.cluster.coordination.JoinHelper.VALIDATE_COMPRESSED_JOIN_ACTION_NAME;
+import static org.opensearch.cluster.coordination.JoinHelper.VALIDATE_JOIN_ACTION_NAME;
 import static org.opensearch.monitor.StatusInfo.Status.HEALTHY;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 import static org.opensearch.node.Node.NODE_NAME_SETTING;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.core.Is.is;
+import static org.mockito.Mockito.mock;
 
 public class JoinHelperTests extends OpenSearchTestCase {
+    private final NamedWriteableRegistry namedWriteableRegistry = DEFAULT_NAMED_WRITABLE_REGISTRY;
 
     public void testJoinDeduplication() {
         DeterministicTaskQueue deterministicTaskQueue = new DeterministicTaskQueue(
@@ -77,20 +97,26 @@ public void testJoinDeduplication() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> localNode,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         JoinHelper joinHelper = new JoinHelper(
             Settings.EMPTY,
             null,
             null,
             transportService,
+            buildRemoteStoreNodeService(transportService, deterministicTaskQueue.getThreadPool()),
             () -> 0L,
             () -> null,
-            (joinRequest, joinCallback) -> { throw new AssertionError(); },
+            (joinRequest, joinCallback) -> {
+                throw new AssertionError();
+            },
             startJoinRequest -> { throw new AssertionError(); },
             Collections.emptyList(),
             (s, p, r) -> {},
-            () -> new StatusInfo(HEALTHY, "info")
+            () -> new StatusInfo(HEALTHY, "info"),
+            nodeCommissioned -> {},
+            namedWriteableRegistry
         );
         transportService.start();
 
@@ -186,74 +212,61 @@ public void testFailedJoinAttemptLogLevel() {
 
         assertThat(
             JoinHelper.FailedJoinAttempt.getLogLevel(
-                new RemoteTransportException("caused by NotMasterException", new NotMasterException("test"))
+                new RemoteTransportException("caused by NotClusterManagerException", new NotClusterManagerException("test"))
             ),
             is(Level.DEBUG)
         );
     }
 
-    public void testJoinValidationRejectsMismatchedClusterUUID() {
+    public void testJoinValidationRejectsMismatchedClusterUUID() throws IOException {
         assertJoinValidationRejectsMismatchedClusterUUID(
-            JoinHelper.VALIDATE_JOIN_ACTION_NAME,
+            VALIDATE_COMPRESSED_JOIN_ACTION_NAME,
             "join validation on cluster state with a different cluster uuid"
         );
-    }
-
-    private void assertJoinValidationRejectsMismatchedClusterUUID(String actionName, String expectedMessage) {
-        DeterministicTaskQueue deterministicTaskQueue = new DeterministicTaskQueue(
-            Settings.builder().put(NODE_NAME_SETTING.getKey(), "node0").build(),
-            random()
+        assertJoinValidationRejectsMismatchedClusterUUID(
+            VALIDATE_JOIN_ACTION_NAME,
+            "join validation on cluster state with a different cluster uuid"
         );
-        MockTransport mockTransport = new MockTransport();
-        DiscoveryNode localNode = new DiscoveryNode("node0", buildNewFakeTransportAddress(), Version.CURRENT);
+    }
 
-        final ClusterState localClusterState = ClusterState.builder(ClusterName.DEFAULT)
-            .metadata(Metadata.builder().generateClusterUuidIfNeeded().clusterUUIDCommitted(true))
-            .build();
-
-        TransportService transportService = mockTransport.createTransportService(
-            Settings.EMPTY,
-            deterministicTaskQueue.getThreadPool(),
-            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
-            x -> localNode,
-            null,
-            Collections.emptySet()
-        );
-        new JoinHelper(
-            Settings.EMPTY,
-            null,
-            null,
-            transportService,
-            () -> 0L,
-            () -> localClusterState,
-            (joinRequest, joinCallback) -> { throw new AssertionError(); },
-            startJoinRequest -> { throw new AssertionError(); },
-            Collections.emptyList(),
-            (s, p, r) -> {},
-            null
-        ); // registers request handler
-        transportService.start();
-        transportService.acceptIncomingRequests();
+    private void assertJoinValidationRejectsMismatchedClusterUUID(String actionName, String expectedMessage) throws IOException {
+        TestClusterSetup testCluster = getTestClusterSetup(null, false);
 
         final ClusterState otherClusterState = ClusterState.builder(ClusterName.DEFAULT)
             .metadata(Metadata.builder().generateClusterUuidIfNeeded())
             .build();
-
+        TransportRequest request;
         final PlainActionFuture<TransportResponse.Empty> future = new PlainActionFuture<>();
-        transportService.sendRequest(
-            localNode,
-            actionName,
-            new ValidateJoinRequest(otherClusterState),
-            new ActionListenerResponseHandler<>(future, in -> TransportResponse.Empty.INSTANCE)
-        );
-        deterministicTaskQueue.runAllTasks();
+        if (actionName.equals(VALIDATE_COMPRESSED_JOIN_ACTION_NAME)) {
+            BytesReference bytes = CompressedStreamUtils.createCompressedStream(
+                testCluster.localNode.getVersion(),
+                otherClusterState::writeTo
+            );
+            request = new BytesTransportRequest(bytes, testCluster.localNode.getVersion());
+            testCluster.transportService.sendRequest(
+                testCluster.localNode,
+                actionName,
+                request,
+                new ActionListenerResponseHandler<>(future, in -> TransportResponse.Empty.INSTANCE)
+            );
+        } else if (actionName.equals(VALIDATE_JOIN_ACTION_NAME)) {
+            request = new ValidateJoinRequest(otherClusterState);
+            testCluster.transportService.sendRequest(
+                testCluster.localNode,
+                actionName,
+                request,
+                new ActionListenerResponseHandler<>(future, in -> TransportResponse.Empty.INSTANCE)
+            );
+        }
+
+        testCluster.deterministicTaskQueue.runAllTasks();
 
         final CoordinationStateRejectedException coordinationStateRejectedException = expectThrows(
             CoordinationStateRejectedException.class,
             future::actionGet
         );
         assertThat(coordinationStateRejectedException.getMessage(), containsString(expectedMessage));
-        assertThat(coordinationStateRejectedException.getMessage(), containsString(localClusterState.metadata().clusterUUID()));
+        assertThat(coordinationStateRejectedException.getMessage(), containsString(testCluster.localClusterState.metadata().clusterUUID()));
         assertThat(coordinationStateRejectedException.getMessage(), containsString(otherClusterState.metadata().clusterUUID()));
     }
 
@@ -270,7 +283,8 @@ public void testJoinFailureOnUnhealthyNodes() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> localNode,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         AtomicReference<StatusInfo> nodeHealthServiceStatus = new AtomicReference<>(new StatusInfo(UNHEALTHY, "unhealthy-info"));
         JoinHelper joinHelper = new JoinHelper(
@@ -278,13 +292,18 @@ public void testJoinFailureOnUnhealthyNodes() {
             null,
             null,
             transportService,
+            buildRemoteStoreNodeService(transportService, deterministicTaskQueue.getThreadPool()),
             () -> 0L,
             () -> null,
-            (joinRequest, joinCallback) -> { throw new AssertionError(); },
+            (joinRequest, joinCallback) -> {
+                throw new AssertionError();
+            },
             startJoinRequest -> { throw new AssertionError(); },
             Collections.emptyList(),
             (s, p, r) -> {},
-            () -> nodeHealthServiceStatus.get()
+            () -> nodeHealthServiceStatus.get(),
+            nodeCommissioned -> {},
+            namedWriteableRegistry
         );
         transportService.start();
 
@@ -324,4 +343,211 @@ public void testJoinFailureOnUnhealthyNodes() {
         CapturedRequest capturedRequest1a = capturedRequests1a[0];
         assertEquals(node1, capturedRequest1a.node);
     }
+
+    public void testSendCompressedValidateJoinFailOnSerializeFailure() throws ExecutionException, InterruptedException, TimeoutException {
+        TestClusterSetup testCluster = getTestClusterSetup(Version.CURRENT, false);
+        final CompletableFuture<Throwable> future = new CompletableFuture<>();
+        testCluster.joinHelper.sendValidateJoinRequest(testCluster.localNode, null, new ActionListener<>() {
+            @Override
+            public void onResponse(TransportResponse.Empty empty) {
+                future.completeExceptionally(new AssertionError("validate join should have failed"));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                future.complete(e);
+            }
+        });
+        Throwable t = future.get(10, TimeUnit.SECONDS);
+        assertTrue(t instanceof NullPointerException);
+    }
+
+    public void testValidateJoinSentWithCorrectActionForVersions() {
+        verifyValidateJoinActionSent(VALIDATE_JOIN_ACTION_NAME, Version.V_2_1_0);
+        verifyValidateJoinActionSent(VALIDATE_JOIN_ACTION_NAME, Version.V_2_7_0);
+        verifyValidateJoinActionSent(VALIDATE_JOIN_ACTION_NAME, Version.V_2_8_0);
+        verifyValidateJoinActionSent(VALIDATE_COMPRESSED_JOIN_ACTION_NAME, Version.CURRENT);
+    }
+
+    private void verifyValidateJoinActionSent(String expectedActionName, Version version) {
+        TestClusterSetup testCluster = getTestClusterSetup(version, true);
+        final CompletableFuture<Throwable> future = new CompletableFuture<>();
+        DiscoveryNode node1 = new DiscoveryNode("node1", buildNewFakeTransportAddress(), version);
+        testCluster.joinHelper.sendValidateJoinRequest(node1, testCluster.localClusterState, new ActionListener<>() {
+            @Override
+            public void onResponse(TransportResponse.Empty empty) {
+                throw new AssertionError("capturing transport shouldn't run");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                future.complete(e);
+            }
+        });
+
+        CapturedRequest[] validateRequests = testCluster.capturingTransport.getCapturedRequestsAndClear();
+        assertEquals(1, validateRequests.length);
+        assertEquals(expectedActionName, validateRequests[0].action);
+    }
+
+    public void testJoinValidationFailsOnDecompressionFailure() {
+        TestClusterSetup testCluster = getTestClusterSetup(Version.CURRENT, false);
+        TransportRequest request;
+        final PlainActionFuture<TransportResponse.Empty> future = new PlainActionFuture<>();
+        request = new BytesTransportRequest(null, testCluster.localNode.getVersion());
+        testCluster.transportService.sendRequest(
+            testCluster.localNode,
+            VALIDATE_COMPRESSED_JOIN_ACTION_NAME,
+            request,
+            new ActionListenerResponseHandler<>(future, in -> TransportResponse.Empty.INSTANCE)
+        );
+        testCluster.deterministicTaskQueue.runAllTasks();
+        expectThrows(NullPointerException.class, future::actionGet);
+    }
+
+    public void testJoinHelperCachingOnClusterState() throws ExecutionException, InterruptedException, TimeoutException {
+        TestClusterSetup testCluster = getTestClusterSetup(Version.CURRENT, false);
+        final CompletableFuture<Throwable> future = new CompletableFuture<>();
+        ActionListener<TransportResponse.Empty> listener = new ActionListener<>() {
+            @Override
+            public void onResponse(TransportResponse.Empty empty) {
+                logger.info("validation successful");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                future.completeExceptionally(new AssertionError("validate join should not fail here"));
+            }
+        };
+        testCluster.joinHelper.sendValidateJoinRequest(testCluster.localNode, testCluster.localClusterState, listener);
+        // validation will pass due to cached cluster state
+        ClusterState randomState = ClusterState.builder(new ClusterName("random"))
+            .stateUUID("random2")
+            .version(testCluster.localClusterState.version())
+            .build();
+        testCluster.joinHelper.sendValidateJoinRequest(testCluster.localNode, randomState, listener);
+
+        final CompletableFuture<Throwable> future2 = new CompletableFuture<>();
+        ActionListener<TransportResponse.Empty> listener2 = new ActionListener<>() {
+            @Override
+            public void onResponse(TransportResponse.Empty empty) {
+                future2.completeExceptionally(new AssertionError("validation should fail now"));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                future2.complete(e);
+            }
+        };
+        ClusterState randomState2 = ClusterState.builder(new ClusterName("random"))
+            .stateUUID("random2")
+            .version(testCluster.localClusterState.version() + 1)
+            .build();
+        // now sending the validate join request will fail due to random cluster uuid because version is changed
+        // and cache will be invalidated
+        testCluster.joinHelper.sendValidateJoinRequest(testCluster.localNode, randomState2, listener2);
+        testCluster.deterministicTaskQueue.runAllTasks();
+
+        Throwable t = future2.get(10, TimeUnit.SECONDS);
+        assertTrue(t instanceof RemoteTransportException);
+        assertTrue(t.getCause() instanceof CoordinationStateRejectedException);
+        assertTrue(t.getCause().getMessage().contains("different cluster uuid"));
+    }
+
+    private TestClusterSetup getTestClusterSetup(Version version, boolean isCapturingTransport) {
+        version = version == null ? Version.CURRENT : version;
+        DeterministicTaskQueue deterministicTaskQueue = new DeterministicTaskQueue(
+            Settings.builder().put(NODE_NAME_SETTING.getKey(), "node0").build(),
+            random()
+        );
+        MockTransport mockTransport = new MockTransport();
+        CapturingTransport capturingTransport = new CapturingTransport();
+        DiscoveryNode localNode = new DiscoveryNode("node0", buildNewFakeTransportAddress(), version);
+
+        final ClusterState localClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(Metadata.builder().generateClusterUuidIfNeeded().clusterUUIDCommitted(true))
+            .build();
+        TransportService transportService;
+        if (isCapturingTransport) {
+            transportService = capturingTransport.createTransportService(
+                Settings.EMPTY,
+                deterministicTaskQueue.getThreadPool(),
+                TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+                x -> localNode,
+                null,
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
+            );
+        } else {
+            transportService = mockTransport.createTransportService(
+                Settings.EMPTY,
+                deterministicTaskQueue.getThreadPool(),
+                TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+                x -> localNode,
+                null,
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
+            );
+        }
+        JoinHelper joinHelper = new JoinHelper(
+            Settings.EMPTY,
+            null,
+            null,
+            transportService,
+            buildRemoteStoreNodeService(transportService, deterministicTaskQueue.getThreadPool()),
+            () -> 0L,
+            () -> localClusterState,
+            (joinRequest, joinCallback) -> {
+                throw new AssertionError();
+            },
+            startJoinRequest -> { throw new AssertionError(); },
+            Collections.emptyList(),
+            (s, p, r) -> {},
+            null,
+            nodeCommissioned -> {},
+            namedWriteableRegistry
+        ); // registers
+           // request
+           // handler
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        return new TestClusterSetup(deterministicTaskQueue, localNode, transportService, localClusterState, joinHelper, capturingTransport);
+    }
+
+    private RemoteStoreNodeService buildRemoteStoreNodeService(TransportService transportService, ThreadPool threadPool) {
+        RepositoriesService repositoriesService = new RepositoriesService(
+            Settings.EMPTY,
+            mock(ClusterService.class),
+            transportService,
+            Collections.emptyMap(),
+            Collections.emptyMap(),
+            threadPool
+        );
+        return new RemoteStoreNodeService(new SetOnce<>(repositoriesService)::get, threadPool);
+    }
+
+    private static class TestClusterSetup {
+        public final DeterministicTaskQueue deterministicTaskQueue;
+        public final DiscoveryNode localNode;
+        public TransportService transportService;
+        public final ClusterState localClusterState;
+        public final JoinHelper joinHelper;
+        public final CapturingTransport capturingTransport;
+
+        public TestClusterSetup(
+            DeterministicTaskQueue deterministicTaskQueue,
+            DiscoveryNode localNode,
+            TransportService transportService,
+            ClusterState localClusterState,
+            JoinHelper joinHelper,
+            CapturingTransport capturingTransport
+        ) {
+            this.deterministicTaskQueue = deterministicTaskQueue;
+            this.localNode = localNode;
+            this.transportService = transportService;
+            this.localClusterState = localClusterState;
+            this.joinHelper = joinHelper;
+            this.capturingTransport = capturingTransport;
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java b/server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java
index a019235c99743..084805bd098fa 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java
@@ -36,29 +36,50 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.List;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.transport.TransportService;
 
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
 import java.util.Map;
+import java.util.stream.Collectors;
 
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
 import static org.opensearch.test.VersionUtils.maxCompatibleVersion;
 import static org.opensearch.test.VersionUtils.randomCompatibleVersion;
 import static org.opensearch.test.VersionUtils.randomVersion;
 import static org.opensearch.test.VersionUtils.randomVersionBetween;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyBoolean;
 import static org.mockito.Mockito.mock;
@@ -104,15 +125,21 @@ public void testPreventJoinClusterWithUnsupportedNodeVersions() {
         builder.add(new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), randomCompatibleVersion(random(), version)));
         DiscoveryNodes nodes = builder.build();
 
+        Metadata metadata = Metadata.EMPTY_METADATA;
+
         final Version maxNodeVersion = nodes.getMaxNodeVersion();
         final Version minNodeVersion = nodes.getMinNodeVersion();
         if (maxNodeVersion.onOrAfter(LegacyESVersion.V_7_0_0)) {
-            final Version tooLow = LegacyESVersion.fromString("6.7.0");
+            final DiscoveryNode tooLowJoiningNode = new DiscoveryNode(
+                UUIDs.base64UUID(),
+                buildNewFakeTransportAddress(),
+                LegacyESVersion.fromString("6.7.0")
+            );
             expectThrows(IllegalStateException.class, () -> {
                 if (randomBoolean()) {
-                    JoinTaskExecutor.ensureNodesCompatibility(tooLow, nodes);
+                    JoinTaskExecutor.ensureNodesCompatibility(tooLowJoiningNode, nodes, metadata);
                 } else {
-                    JoinTaskExecutor.ensureNodesCompatibility(tooLow, minNodeVersion, maxNodeVersion);
+                    JoinTaskExecutor.ensureNodesCompatibility(tooLowJoiningNode, nodes, metadata, minNodeVersion, maxNodeVersion);
                 }
             });
         }
@@ -126,11 +153,11 @@ public void testPreventJoinClusterWithUnsupportedNodeVersions() {
         // we have to stick with the same major
             minNodeVersion : maxNodeVersion.minimumCompatibilityVersion();
         final Version justGood = randomVersionBetween(random(), minGoodVersion, maxCompatibleVersion(minNodeVersion));
-
+        final DiscoveryNode justGoodJoiningNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), justGood);
         if (randomBoolean()) {
-            JoinTaskExecutor.ensureNodesCompatibility(justGood, nodes);
+            JoinTaskExecutor.ensureNodesCompatibility(justGoodJoiningNode, nodes, metadata);
         } else {
-            JoinTaskExecutor.ensureNodesCompatibility(justGood, minNodeVersion, maxNodeVersion);
+            JoinTaskExecutor.ensureNodesCompatibility(justGoodJoiningNode, nodes, metadata, minNodeVersion, maxNodeVersion);
         }
     }
 
@@ -158,17 +185,27 @@ public void testSuccess() {
     }
 
     public void testUpdatesNodeWithNewRoles() throws Exception {
-        // Node roles vary by version, and new roles are suppressed for BWC. This means we can receive a join from a node that's already
-        // in the cluster but with a different set of roles: the node didn't change roles, but the cluster state came via an older master.
+        // Node roles vary by version, and new roles are suppressed for BWC.
+        // This means we can receive a join from a node that's already in the cluster but with a different set of roles:
+        // the node didn't change roles, but the cluster state came via an older cluster-manager.
         // In this case we must properly process its join to ensure that the roles are correct.
 
         final AllocationService allocationService = mock(AllocationService.class);
         when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
         final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = mock(RemoteStoreNodeService.class);
+        when(remoteStoreNodeService.updateRepositoriesMetadata(any(), any())).thenReturn(new RepositoriesMetadata(Collections.emptyList()));
 
-        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(Settings.EMPTY, allocationService, logger, rerouteService, null);
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
 
-        final DiscoveryNode masterNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
 
         final DiscoveryNode actualNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
         final DiscoveryNode bwcNode = new DiscoveryNode(
@@ -183,7 +220,13 @@ public void testUpdatesNodeWithNewRoles() throws Exception {
             actualNode.getVersion()
         );
         final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
-            .nodes(DiscoveryNodes.builder().add(masterNode).localNodeId(masterNode.getId()).masterNodeId(masterNode.getId()).add(bwcNode))
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+                    .add(bwcNode)
+            )
             .build();
 
         final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
@@ -222,6 +265,7 @@ public void testUpdatesNodeWithOpenSearchVersionForExistingAndNewNodes() throws
         channelVersions.put(node_6, LegacyESVersion.V_7_10_0);
 
         final TransportService transportService = mock(TransportService.class);
+        final RemoteStoreNodeService remoteStoreNodeService = mock(RemoteStoreNodeService.class);
         when(transportService.getChannelVersion(any())).thenReturn(channelVersions);
         DiscoveryNodes.Builder nodes = new DiscoveryNodes.Builder().localNodeId(node_1);
         nodes.add(new DiscoveryNode(node_1, buildNewFakeTransportAddress(), LegacyESVersion.V_7_10_2));
@@ -237,7 +281,8 @@ public void testUpdatesNodeWithOpenSearchVersionForExistingAndNewNodes() throws
             allocationService,
             logger,
             rerouteService,
-            transportService
+            transportService,
+            remoteStoreNodeService
         );
         final DiscoveryNode existing_node_3 = clusterState.nodes().get(node_3);
         final DiscoveryNode node_3_new_join = new DiscoveryNode(
@@ -272,4 +317,641 @@ public void testUpdatesNodeWithOpenSearchVersionForExistingAndNewNodes() throws
         // 7.9.0 node without active channel but shouldn't get removed
         assertEquals(LegacyESVersion.V_7_10_0, resultNodes.get(node_7).getVersion());
     }
+
+    /**
+     * Validate isBecomeClusterManagerTask() can identify "become cluster manager task" properly
+     */
+    public void testIsBecomeClusterManagerTask() {
+        JoinTaskExecutor.Task joinTaskOfMaster = JoinTaskExecutor.newBecomeMasterTask();
+        assertThat(joinTaskOfMaster.isBecomeClusterManagerTask(), is(true));
+        JoinTaskExecutor.Task joinTaskOfClusterManager = JoinTaskExecutor.newBecomeClusterManagerTask();
+        assertThat(joinTaskOfClusterManager.isBecomeClusterManagerTask(), is(true));
+    }
+
+    public void testJoinClusterWithNoDecommission() {
+        Settings.builder().build();
+        Metadata.Builder metaBuilder = Metadata.builder();
+        Metadata metadata = metaBuilder.build();
+        DiscoveryNode discoveryNode = newDiscoveryNode(Collections.singletonMap("zone", "zone-2"));
+        JoinTaskExecutor.ensureNodeCommissioned(discoveryNode, metadata);
+    }
+
+    public void testPreventJoinClusterWithDecommission() {
+        Settings.builder().build();
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-1");
+        DecommissionStatus decommissionStatus = randomFrom(
+            DecommissionStatus.IN_PROGRESS,
+            DecommissionStatus.SUCCESSFUL,
+            DecommissionStatus.DRAINING
+        );
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            decommissionStatus,
+            randomAlphaOfLength(10)
+        );
+        Metadata metadata = Metadata.builder().decommissionAttributeMetadata(decommissionAttributeMetadata).build();
+        DiscoveryNode discoveryNode = newDiscoveryNode(Collections.singletonMap("zone", "zone-1"));
+        expectThrows(NodeDecommissionedException.class, () -> JoinTaskExecutor.ensureNodeCommissioned(discoveryNode, metadata));
+    }
+
+    public void testJoinClusterWithDifferentDecommission() {
+        Settings.builder().build();
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-1");
+        DecommissionStatus decommissionStatus = randomFrom(
+            DecommissionStatus.INIT,
+            DecommissionStatus.IN_PROGRESS,
+            DecommissionStatus.SUCCESSFUL
+        );
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            decommissionStatus,
+            randomAlphaOfLength(10)
+        );
+        Metadata metadata = Metadata.builder().decommissionAttributeMetadata(decommissionAttributeMetadata).build();
+
+        DiscoveryNode discoveryNode = newDiscoveryNode(Collections.singletonMap("zone", "zone-2"));
+        JoinTaskExecutor.ensureNodeCommissioned(discoveryNode, metadata);
+    }
+
+    public void testJoinFailedForDecommissionedNode() throws Exception {
+        final AllocationService allocationService = mock(AllocationService.class);
+        when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
+        final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = mock(RemoteStoreNodeService.class);
+
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
+
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
+
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone1");
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.SUCCESSFUL,
+            randomAlphaOfLength(10)
+        );
+        final ClusterState clusterManagerClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+            )
+            .metadata(Metadata.builder().decommissionAttributeMetadata(decommissionAttributeMetadata))
+            .build();
+
+        final DiscoveryNode decommissionedNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            Collections.singletonMap("zone", "zone1"),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        String decommissionedNodeID = decommissionedNode.getId();
+
+        final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
+            clusterManagerClusterState,
+            List.of(new JoinTaskExecutor.Task(decommissionedNode, "test"))
+        );
+        assertThat(result.executionResults.entrySet(), hasSize(1));
+        final ClusterStateTaskExecutor.TaskResult taskResult = result.executionResults.values().iterator().next();
+        assertFalse(taskResult.isSuccess());
+        assertTrue(taskResult.getFailure() instanceof NodeDecommissionedException);
+        assertFalse(result.resultingState.getNodes().nodeExists(decommissionedNodeID));
+    }
+
+    public void testJoinClusterWithDecommissionFailed() {
+        Settings.builder().build();
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-1");
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.FAILED,
+            randomAlphaOfLength(10)
+        );
+        Metadata metadata = Metadata.builder().decommissionAttributeMetadata(decommissionAttributeMetadata).build();
+
+        DiscoveryNode discoveryNode = newDiscoveryNode(Collections.singletonMap("zone", "zone-1"));
+        JoinTaskExecutor.ensureNodeCommissioned(discoveryNode, metadata);
+    }
+
+    public void testJoinClusterWithNonRemoteStoreNodeJoining() {
+        DiscoveryNode joiningNode = newDiscoveryNode(Collections.emptyMap());
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(joiningNode).build())
+            .build();
+
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testJoinClusterWithRemoteStoreNodeJoining() {
+        DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO));
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(joiningNode).build())
+            .build();
+
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testJoinClusterWithNonRemoteStoreNodeJoiningNonRemoteStoreCluster() {
+        final DiscoveryNode existingNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(Collections.emptyMap());
+
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testPreventJoinClusterWithRemoteStoreNodeJoiningNonRemoteStoreCluster() {
+        final DiscoveryNode existingNode = new DiscoveryNode(UUIDs.base64UUID(), buildNewFakeTransportAddress(), Version.CURRENT);
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO));
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+        );
+        assertTrue(e.getMessage().equals("a remote store node [" + joiningNode + "] is trying to join a non remote " + "store cluster"));
+    }
+
+    public void testJoinClusterWithRemoteStoreNodeJoiningRemoteStoreCluster() {
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO));
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testPreventJoinClusterWithRemoteStoreNodeWithDifferentAttributesJoiningRemoteStoreCluster() {
+        Map<String, String> existingNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            existingNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        for (Map.Entry<String, String> nodeAttribute : existingNodeAttributes.entrySet()) {
+            if (nodeAttribute.getKey() != REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY
+                && nodeAttribute.getKey() != REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY
+                && nodeAttribute.getKey() != REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY) {
+                remoteStoreNodeAttributes.put(nodeAttribute.getKey(), nodeAttribute.getValue() + "-new");
+                validateAttributes(remoteStoreNodeAttributes, currentState, existingNode);
+                remoteStoreNodeAttributes.put(nodeAttribute.getKey(), nodeAttribute.getValue());
+            }
+        }
+    }
+
+    public void testPreventJoinClusterWithRemoteStoreNodeWithDifferentNameAttributesJoiningRemoteStoreCluster() {
+        Map<String, String> existingNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            existingNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        for (Map.Entry<String, String> nodeAttribute : existingNodeAttributes.entrySet()) {
+            if (REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY.equals(nodeAttribute.getKey())) {
+                Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO + "new", TRANSLOG_REPO);
+                validateAttributes(remoteStoreNodeAttributes, currentState, existingNode);
+            } else if (REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY.equals(nodeAttribute.getKey())) {
+                Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO + "new");
+                validateAttributes(remoteStoreNodeAttributes, currentState, existingNode);
+            } else if (REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY.equals(nodeAttribute.getKey())) {
+                Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(
+                    SEGMENT_REPO,
+                    TRANSLOG_REPO,
+                    CLUSTER_STATE_REPO + "new"
+                );
+                validateAttributes(remoteStoreNodeAttributes, currentState, existingNode);
+            }
+        }
+    }
+
+    public void testPreventJoinClusterWithNonRemoteStoreNodeJoiningRemoteStoreCluster() {
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(Collections.emptyMap());
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+        );
+        assertTrue(e.getMessage().equals("a non remote store node [" + joiningNode + "] is trying to join a remote " + "store cluster"));
+    }
+
+    public void testPreventJoinClusterWithRemoteStoreNodeWithPartialAttributesJoiningRemoteStoreCluster() {
+        Map<String, String> existingNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            existingNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        for (Map.Entry<String, String> nodeAttribute : existingNodeAttributes.entrySet()) {
+            remoteStoreNodeAttributes.put(nodeAttribute.getKey(), null);
+            DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes);
+            Exception e = assertThrows(
+                IllegalStateException.class,
+                () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+            );
+            assertTrue(
+                e.getMessage().equals("joining node [" + joiningNode + "] doesn't have the node attribute [" + nodeAttribute.getKey() + "]")
+            );
+
+            remoteStoreNodeAttributes.put(nodeAttribute.getKey(), nodeAttribute.getValue());
+        }
+    }
+
+    public void testUpdatesClusterStateWithSingleNodeCluster() throws Exception {
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        final AllocationService allocationService = mock(AllocationService.class);
+        when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
+        final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = new RemoteStoreNodeService(
+            new SetOnce<>(mock(RepositoriesService.class))::get,
+            null
+        );
+
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
+
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+            )
+            .build();
+
+        final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
+            clusterState,
+            List.of(new JoinTaskExecutor.Task(clusterManagerNode, "elect leader"))
+        );
+        assertThat(result.executionResults.entrySet(), hasSize(1));
+        final ClusterStateTaskExecutor.TaskResult taskResult = result.executionResults.values().iterator().next();
+        assertTrue(taskResult.isSuccess());
+        validateRepositoryMetadata(result.resultingState, clusterManagerNode, 3);
+    }
+
+    public void testUpdatesClusterStateWithMultiNodeCluster() throws Exception {
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
+        final AllocationService allocationService = mock(AllocationService.class);
+        when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
+        final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = new RemoteStoreNodeService(
+            new SetOnce<>(mock(RepositoriesService.class))::get,
+            null
+        );
+
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
+
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final RepositoryMetadata segmentRepositoryMetadata = buildRepositoryMetadata(clusterManagerNode, SEGMENT_REPO);
+        final RepositoryMetadata translogRepositoryMetadata = buildRepositoryMetadata(clusterManagerNode, TRANSLOG_REPO);
+        List<RepositoryMetadata> repositoriesMetadata = new ArrayList<>() {
+            {
+                add(segmentRepositoryMetadata);
+                add(translogRepositoryMetadata);
+            }
+        };
+
+        final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+            )
+            .metadata(Metadata.builder().putCustom(RepositoriesMetadata.TYPE, new RepositoriesMetadata(repositoriesMetadata)))
+            .build();
+
+        final DiscoveryNode joiningNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
+            clusterState,
+            List.of(new JoinTaskExecutor.Task(joiningNode, "test"))
+        );
+        assertThat(result.executionResults.entrySet(), hasSize(1));
+        final ClusterStateTaskExecutor.TaskResult taskResult = result.executionResults.values().iterator().next();
+        assertTrue(taskResult.isSuccess());
+        validateRepositoryMetadata(result.resultingState, clusterManagerNode, 3);
+    }
+
+    public void testUpdatesClusterStateWithSingleNodeClusterAndSameRepository() throws Exception {
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(COMMON_REPO, COMMON_REPO);
+        final AllocationService allocationService = mock(AllocationService.class);
+        when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
+        final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = new RemoteStoreNodeService(
+            new SetOnce<>(mock(RepositoriesService.class))::get,
+            null
+        );
+
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
+
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+            )
+            .build();
+
+        final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
+            clusterState,
+            List.of(new JoinTaskExecutor.Task(clusterManagerNode, "elect leader"))
+        );
+        assertThat(result.executionResults.entrySet(), hasSize(1));
+        final ClusterStateTaskExecutor.TaskResult taskResult = result.executionResults.values().iterator().next();
+        assertTrue(taskResult.isSuccess());
+        validateRepositoryMetadata(result.resultingState, clusterManagerNode, 2);
+    }
+
+    public void testUpdatesClusterStateWithMultiNodeClusterAndSameRepository() throws Exception {
+        Map<String, String> remoteStoreNodeAttributes = remoteStoreNodeAttributes(COMMON_REPO, COMMON_REPO);
+        final AllocationService allocationService = mock(AllocationService.class);
+        when(allocationService.adaptAutoExpandReplicas(any())).then(invocationOnMock -> invocationOnMock.getArguments()[0]);
+        final RerouteService rerouteService = (reason, priority, listener) -> listener.onResponse(null);
+        final RemoteStoreNodeService remoteStoreNodeService = new RemoteStoreNodeService(
+            new SetOnce<>(mock(RepositoriesService.class))::get,
+            null
+        );
+
+        final JoinTaskExecutor joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            rerouteService,
+            null,
+            remoteStoreNodeService
+        );
+
+        final DiscoveryNode clusterManagerNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final RepositoryMetadata segmentRepositoryMetadata = buildRepositoryMetadata(clusterManagerNode, COMMON_REPO);
+        List<RepositoryMetadata> repositoriesMetadata = new ArrayList<>() {
+            {
+                add(segmentRepositoryMetadata);
+            }
+        };
+
+        final ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(clusterManagerNode)
+                    .localNodeId(clusterManagerNode.getId())
+                    .clusterManagerNodeId(clusterManagerNode.getId())
+            )
+            .metadata(Metadata.builder().putCustom(RepositoriesMetadata.TYPE, new RepositoriesMetadata(repositoriesMetadata)))
+            .build();
+
+        final DiscoveryNode joiningNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final ClusterStateTaskExecutor.ClusterTasksResult<JoinTaskExecutor.Task> result = joinTaskExecutor.execute(
+            clusterState,
+            List.of(new JoinTaskExecutor.Task(joiningNode, "test"))
+        );
+        assertThat(result.executionResults.entrySet(), hasSize(1));
+        final ClusterStateTaskExecutor.TaskResult taskResult = result.executionResults.values().iterator().next();
+        assertTrue(taskResult.isSuccess());
+        validateRepositoryMetadata(result.resultingState, clusterManagerNode, 2);
+    }
+
+    private void validateRepositoryMetadata(ClusterState updatedState, DiscoveryNode existingNode, int expectedRepositories)
+        throws Exception {
+
+        final RepositoriesMetadata repositoriesMetadata = updatedState.metadata().custom(RepositoriesMetadata.TYPE);
+        assertTrue(repositoriesMetadata.repositories().size() == expectedRepositories);
+        if (repositoriesMetadata.repositories().size() == 2 || repositoriesMetadata.repositories().size() == 3) {
+            final RepositoryMetadata segmentRepositoryMetadata = buildRepositoryMetadata(existingNode, SEGMENT_REPO);
+            final RepositoryMetadata translogRepositoryMetadata = buildRepositoryMetadata(existingNode, TRANSLOG_REPO);
+            for (RepositoryMetadata repositoryMetadata : repositoriesMetadata.repositories()) {
+                if (repositoryMetadata.name().equals(segmentRepositoryMetadata.name())) {
+                    assertTrue(segmentRepositoryMetadata.equalsIgnoreGenerations(repositoryMetadata));
+                } else if (repositoryMetadata.name().equals(translogRepositoryMetadata.name())) {
+                    assertTrue(translogRepositoryMetadata.equalsIgnoreGenerations(repositoryMetadata));
+                } else if (repositoriesMetadata.repositories().size() == 3) {
+                    final RepositoryMetadata clusterStateRepoMetadata = buildRepositoryMetadata(existingNode, CLUSTER_STATE_REPO);
+                    assertTrue(clusterStateRepoMetadata.equalsIgnoreGenerations(repositoryMetadata));
+                }
+            }
+        } else if (repositoriesMetadata.repositories().size() == 1) {
+            final RepositoryMetadata repositoryMetadata = buildRepositoryMetadata(existingNode, COMMON_REPO);
+            assertTrue(repositoryMetadata.equalsIgnoreGenerations(repositoriesMetadata.repositories().get(0)));
+        } else {
+            throw new Exception("Stack overflow example: checkedExceptionThrower");
+        }
+    }
+
+    private DiscoveryNode newDiscoveryNode(Map<String, String> attributes) {
+        return new DiscoveryNode(
+            randomAlphaOfLength(10),
+            randomAlphaOfLength(10),
+            buildNewFakeTransportAddress(),
+            attributes,
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+    }
+
+    private static final String SEGMENT_REPO = "segment-repo";
+    private static final String TRANSLOG_REPO = "translog-repo";
+    private static final String CLUSTER_STATE_REPO = "cluster-state-repo";
+    private static final String COMMON_REPO = "remote-repo";
+
+    private Map<String, String> remoteStoreNodeAttributes(String segmentRepoName, String translogRepoName) {
+        return remoteStoreNodeAttributes(segmentRepoName, translogRepoName, CLUSTER_STATE_REPO);
+    }
+
+    private Map<String, String> remoteStoreNodeAttributes(String segmentRepoName, String translogRepoName, String clusterStateRepo) {
+        String segmentRepositoryTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            segmentRepoName
+        );
+        String segmentRepositorySettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            segmentRepoName
+        );
+        String translogRepositoryTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            translogRepoName
+        );
+        String translogRepositorySettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            translogRepoName
+        );
+        String clusterStateRepositoryTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            clusterStateRepo
+        );
+        String clusterStateRepositorySettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            clusterStateRepo
+        );
+
+        return new HashMap<>() {
+            {
+                put(REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, segmentRepoName);
+                put(segmentRepositoryTypeAttributeKey, "s3");
+                put(segmentRepositorySettingsAttributeKeyPrefix + "bucket", "segment_bucket");
+                put(segmentRepositorySettingsAttributeKeyPrefix + "base_path", "/segment/path");
+                put(REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, translogRepoName);
+                putIfAbsent(translogRepositoryTypeAttributeKey, "s3");
+                putIfAbsent(translogRepositorySettingsAttributeKeyPrefix + "bucket", "translog_bucket");
+                putIfAbsent(translogRepositorySettingsAttributeKeyPrefix + "base_path", "/translog/path");
+                put(REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, clusterStateRepo);
+                putIfAbsent(clusterStateRepositoryTypeAttributeKey, "s3");
+                putIfAbsent(clusterStateRepositorySettingsAttributeKeyPrefix + "bucket", "state_bucket");
+                putIfAbsent(clusterStateRepositorySettingsAttributeKeyPrefix + "base_path", "/state/path");
+            }
+        };
+    }
+
+    private void validateAttributes(Map<String, String> remoteStoreNodeAttributes, ClusterState currentState, DiscoveryNode existingNode) {
+        DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes);
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+        );
+        assertEquals(
+            e.getMessage(),
+            "a remote store node ["
+                + joiningNode
+                + "] is trying to join a remote store cluster with incompatible node attributes in "
+                + "comparison with existing node ["
+                + existingNode
+                + "]"
+        );
+    }
+
+    private RepositoryMetadata buildRepositoryMetadata(DiscoveryNode node, String name) {
+        Map<String, String> nodeAttributes = node.getAttributes();
+        String type = nodeAttributes.get(String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, name));
+
+        String settingsAttributeKeyPrefix = String.format(Locale.getDefault(), REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX, name);
+        Map<String, String> settingsMap = node.getAttributes()
+            .keySet()
+            .stream()
+            .filter(key -> key.startsWith(settingsAttributeKeyPrefix))
+            .collect(Collectors.toMap(key -> key.replace(settingsAttributeKeyPrefix, ""), key -> node.getAttributes().get(key)));
+
+        Settings.Builder settings = Settings.builder();
+        settingsMap.entrySet().forEach(entry -> settings.put(entry.getKey(), entry.getValue()));
+
+        settings.put(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING.getKey(), true);
+
+        return new RepositoryMetadata(name, type, settings.build());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/LeaderCheckerTests.java b/server/src/test/java/org/opensearch/cluster/coordination/LeaderCheckerTests.java
index 69dc332e2bd29..8915f4c5c1274 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/LeaderCheckerTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/LeaderCheckerTests.java
@@ -38,20 +38,21 @@
 import org.opensearch.cluster.coordination.LeaderChecker.LeaderCheckRequest;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.monitor.StatusInfo;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -165,7 +166,8 @@ public String toString() {
             NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -281,7 +283,8 @@ public String toString() {
             NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -393,7 +396,8 @@ public String toString() {
             NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -438,7 +442,8 @@ public void testLeaderBehaviour() {
             NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -453,7 +458,7 @@ public void testLeaderBehaviour() {
         final DiscoveryNodes discoveryNodes = DiscoveryNodes.builder()
             .add(localNode)
             .localNodeId(localNode.getId())
-            .masterNodeId(localNode.getId())
+            .clusterManagerNodeId(localNode.getId())
             .build();
 
         {
@@ -498,7 +503,7 @@ public void testLeaderBehaviour() {
         }
 
         {
-            leaderChecker.setCurrentNodes(DiscoveryNodes.builder(discoveryNodes).add(otherNode).masterNodeId(null).build());
+            leaderChecker.setCurrentNodes(DiscoveryNodes.builder(discoveryNodes).add(otherNode).clusterManagerNodeId(null).build());
 
             final CapturingTransportResponseHandler handler = new CapturingTransportResponseHandler();
             transportService.sendRequest(localNode, LEADER_CHECK_ACTION_NAME, new LeaderCheckRequest(otherNode), handler);
@@ -509,7 +514,7 @@ public void testLeaderBehaviour() {
             CoordinationStateRejectedException cause = (CoordinationStateRejectedException) handler.transportException.getRootCause();
             assertThat(
                 cause.getMessage(),
-                equalTo("rejecting leader check from [" + otherNode + "] sent to a node that is no longer the master")
+                equalTo("rejecting leader check from [" + otherNode + "] sent to a node that is no longer the cluster-manager")
             );
         }
     }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/MessagesTests.java b/server/src/test/java/org/opensearch/cluster/coordination/MessagesTests.java
index c6d97c641e2e1..58ca768edbb46 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/MessagesTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/MessagesTests.java
@@ -35,9 +35,9 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Optional;
 
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceRenamedSettingTests.java b/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceRenamedSettingTests.java
new file mode 100644
index 0000000000000..8a85544299618
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceRenamedSettingTests.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Arrays;
+import java.util.Set;
+
+/**
+ * A unit test to validate the former name of the setting 'cluster.no_cluster_manager_block' still take effect,
+ * after it is deprecated, so that the backwards compatibility is maintained.
+ * The test can be removed along with removing support of the deprecated setting.
+ */
+public class NoClusterManagerBlockServiceRenamedSettingTests extends OpenSearchTestCase {
+
+    /**
+     * Validate the both settings are known and supported.
+     */
+    public void testReindexSettingsExist() {
+        Set<Setting<?>> settings = ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
+        assertTrue(
+            "Both 'cluster.no_cluster_manager_block' and its predecessor should be supported built-in settings.",
+            settings.containsAll(
+                Arrays.asList(
+                    NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING,
+                    NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING
+                )
+            )
+        );
+    }
+
+    /**
+     * Validate the default value of the both settings is the same.
+     */
+    public void testSettingFallback() {
+        assertEquals(
+            NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING.get(Settings.EMPTY),
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(Settings.EMPTY)
+
+        );
+    }
+
+    /**
+     * Validate the new setting can be configured correctly, and it doesn't impact the old setting.
+     */
+    public void testSettingGetValue() {
+        Settings settings = Settings.builder().put("cluster.no_cluster_manager_block", "all").build();
+        assertEquals(
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL,
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings)
+        );
+        assertEquals(
+            NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING.getDefault(Settings.EMPTY),
+            NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING.get(settings)
+        );
+    }
+
+    /**
+     * Validate the value of the old setting will be applied to the new setting, if the new setting is not configured.
+     */
+    public void testSettingGetValueWithFallback() {
+        Settings settings = Settings.builder().put("cluster.no_master_block", "metadata_write").build();
+        assertEquals(
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES,
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings)
+        );
+        assertSettingDeprecationsAndWarnings(new Setting<?>[] { NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING });
+    }
+
+    /**
+     * Validate the value of the old setting will be ignored, if the new setting is configured.
+     */
+    public void testSettingGetValueWhenBothAreConfigured() {
+        Settings settings = Settings.builder()
+            .put("cluster.no_cluster_manager_block", "all")
+            .put("cluster.no_master_block", "metadata_write")
+            .build();
+        assertEquals(
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL,
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings)
+        );
+        assertEquals(
+            NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES,
+            NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING.get(settings)
+        );
+        assertSettingDeprecationsAndWarnings(new Setting<?>[] { NoClusterManagerBlockService.NO_MASTER_BLOCK_SETTING });
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceTests.java b/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceTests.java
new file mode 100644
index 0000000000000..d9ff21204387d
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/coordination/NoClusterManagerBlockServiceTests.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.coordination;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES;
+import static org.opensearch.common.settings.ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
+import static org.hamcrest.Matchers.sameInstance;
+
+public class NoClusterManagerBlockServiceTests extends OpenSearchTestCase {
+
+    private NoClusterManagerBlockService noClusterManagerBlockService;
+    private ClusterSettings clusterSettings;
+
+    private void createService(Settings settings) {
+        clusterSettings = new ClusterSettings(settings, BUILT_IN_CLUSTER_SETTINGS);
+        noClusterManagerBlockService = new NoClusterManagerBlockService(settings, clusterSettings);
+    }
+
+    private void assertDeprecatedWarningEmitted() {
+        assertWarnings(
+            "[discovery.zen.no_master_block] setting was deprecated in OpenSearch and will be removed in a future release! "
+                + "See the breaking changes documentation for the next major version."
+        );
+    }
+
+    public void testBlocksWritesByDefault() {
+        createService(Settings.EMPTY);
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES));
+    }
+
+    public void testBlocksWritesIfConfiguredBySetting() {
+        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_WRITES));
+    }
+
+    public void testBlocksAllIfConfiguredBySetting() {
+        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_ALL));
+    }
+
+    public void testBlocksMetadataWritesIfConfiguredBySetting() {
+        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES));
+    }
+
+    public void testRejectsInvalidSetting() {
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "unknown").build())
+        );
+    }
+
+    public void testSettingCanBeUpdated() {
+        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_ALL));
+
+        clusterSettings.applySettings(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_WRITES));
+
+        clusterSettings.applySettings(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write").build());
+        assertThat(noClusterManagerBlockService.getNoClusterManagerBlock(), sameInstance(NO_CLUSTER_MANAGER_BLOCK_METADATA_WRITES));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceRenamedSettingTests.java b/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceRenamedSettingTests.java
deleted file mode 100644
index 2c988cad5f79c..0000000000000
--- a/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceRenamedSettingTests.java
+++ /dev/null
@@ -1,87 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-package org.opensearch.cluster.coordination;
-
-import org.opensearch.common.settings.ClusterSettings;
-import org.opensearch.common.settings.Setting;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.util.Arrays;
-import java.util.Set;
-
-/**
- * A unit test to validate the former name of the setting 'cluster.no_cluster_manager_block' still take effect,
- * after it is deprecated, so that the backwards compatibility is maintained.
- * The test can be removed along with removing support of the deprecated setting.
- */
-public class NoMasterBlockServiceRenamedSettingTests extends OpenSearchTestCase {
-
-    /**
-     * Validate the both settings are known and supported.
-     */
-    public void testReindexSettingsExist() {
-        Set<Setting<?>> settings = ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
-        assertTrue(
-            "Both 'cluster.no_cluster_manager_block' and its predecessor should be supported built-in settings.",
-            settings.containsAll(
-                Arrays.asList(NoMasterBlockService.NO_MASTER_BLOCK_SETTING, NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING)
-            )
-        );
-    }
-
-    /**
-     * Validate the default value of the both settings is the same.
-     */
-    public void testSettingFallback() {
-        assertEquals(
-            NoMasterBlockService.NO_MASTER_BLOCK_SETTING.get(Settings.EMPTY),
-            NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(Settings.EMPTY)
-
-        );
-    }
-
-    /**
-     * Validate the new setting can be configured correctly, and it doesn't impact the old setting.
-     */
-    public void testSettingGetValue() {
-        Settings settings = Settings.builder().put("cluster.no_cluster_manager_block", "all").build();
-        assertEquals(NoMasterBlockService.NO_MASTER_BLOCK_ALL, NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings));
-        assertEquals(
-            NoMasterBlockService.NO_MASTER_BLOCK_SETTING.getDefault(Settings.EMPTY),
-            NoMasterBlockService.NO_MASTER_BLOCK_SETTING.get(settings)
-        );
-    }
-
-    /**
-     * Validate the value of the old setting will be applied to the new setting, if the new setting is not configured.
-     */
-    public void testSettingGetValueWithFallback() {
-        Settings settings = Settings.builder().put("cluster.no_master_block", "metadata_write").build();
-        assertEquals(
-            NoMasterBlockService.NO_MASTER_BLOCK_METADATA_WRITES,
-            NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings)
-        );
-        assertSettingDeprecationsAndWarnings(new Setting<?>[] { NoMasterBlockService.NO_MASTER_BLOCK_SETTING });
-    }
-
-    /**
-     * Validate the value of the old setting will be ignored, if the new setting is configured.
-     */
-    public void testSettingGetValueWhenBothAreConfigured() {
-        Settings settings = Settings.builder()
-            .put("cluster.no_cluster_manager_block", "all")
-            .put("cluster.no_master_block", "metadata_write")
-            .build();
-        assertEquals(NoMasterBlockService.NO_MASTER_BLOCK_ALL, NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.get(settings));
-        assertEquals(NoMasterBlockService.NO_MASTER_BLOCK_METADATA_WRITES, NoMasterBlockService.NO_MASTER_BLOCK_SETTING.get(settings));
-        assertSettingDeprecationsAndWarnings(new Setting<?>[] { NoMasterBlockService.NO_MASTER_BLOCK_SETTING });
-    }
-
-}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceTests.java b/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceTests.java
deleted file mode 100644
index a637826951f87..0000000000000
--- a/server/src/test/java/org/opensearch/cluster/coordination/NoMasterBlockServiceTests.java
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.cluster.coordination;
-
-import org.opensearch.common.settings.ClusterSettings;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.test.OpenSearchTestCase;
-
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_ALL;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_METADATA_WRITES;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_WRITES;
-import static org.opensearch.common.settings.ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
-import static org.hamcrest.Matchers.sameInstance;
-
-public class NoMasterBlockServiceTests extends OpenSearchTestCase {
-
-    private NoMasterBlockService noMasterBlockService;
-    private ClusterSettings clusterSettings;
-
-    private void createService(Settings settings) {
-        clusterSettings = new ClusterSettings(settings, BUILT_IN_CLUSTER_SETTINGS);
-        noMasterBlockService = new NoMasterBlockService(settings, clusterSettings);
-    }
-
-    private void assertDeprecatedWarningEmitted() {
-        assertWarnings(
-            "[discovery.zen.no_master_block] setting was deprecated in OpenSearch and will be removed in a future release! "
-                + "See the breaking changes documentation for the next major version."
-        );
-    }
-
-    public void testBlocksWritesByDefault() {
-        createService(Settings.EMPTY);
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_WRITES));
-    }
-
-    public void testBlocksWritesIfConfiguredBySetting() {
-        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_WRITES));
-    }
-
-    public void testBlocksAllIfConfiguredBySetting() {
-        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_ALL));
-    }
-
-    public void testBlocksMetadataWritesIfConfiguredBySetting() {
-        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_METADATA_WRITES));
-    }
-
-    public void testRejectsInvalidSetting() {
-        expectThrows(
-            IllegalArgumentException.class,
-            () -> createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "unknown").build())
-        );
-    }
-
-    public void testSettingCanBeUpdated() {
-        createService(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "all").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_ALL));
-
-        clusterSettings.applySettings(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "write").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_WRITES));
-
-        clusterSettings.applySettings(Settings.builder().put(NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), "metadata_write").build());
-        assertThat(noMasterBlockService.getNoMasterBlock(), sameInstance(NO_MASTER_BLOCK_METADATA_WRITES));
-    }
-}
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/NodeJoinTests.java b/server/src/test/java/org/opensearch/cluster/coordination/NodeJoinTests.java
index 3b309908a1df0..d94f3fb304fe2 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/NodeJoinTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/NodeJoinTests.java
@@ -33,27 +33,35 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.cluster.decommission.NodeDecommissionedException;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.cluster.service.FakeThreadPoolMasterService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.ClusterManagerService;
+import org.opensearch.cluster.service.FakeThreadPoolClusterManagerService;
 import org.opensearch.cluster.service.MasterServiceTests;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.BaseFuture;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.node.Node;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
@@ -63,7 +71,7 @@
 import org.opensearch.transport.TestTransportChannel;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportRequest;
-import org.opensearch.transport.TransportResponse;
+import org.opensearch.transport.TransportRequestOptions;
 import org.opensearch.transport.TransportService;
 import org.junit.After;
 import org.junit.AfterClass;
@@ -84,6 +92,8 @@
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singleton;
@@ -98,7 +108,7 @@ public class NodeJoinTests extends OpenSearchTestCase {
 
     private static ThreadPool threadPool;
 
-    private MasterService masterService;
+    private ClusterManagerService clusterManagerService;
     private Coordinator coordinator;
     private DeterministicTaskQueue deterministicTaskQueue;
     private Transport transport;
@@ -117,7 +127,7 @@ public static void afterClass() {
     @After
     public void tearDown() throws Exception {
         super.tearDown();
-        masterService.close();
+        clusterManagerService.close();
     }
 
     private static ClusterState initialState(DiscoveryNode localNode, long term, long version, VotingConfiguration config) {
@@ -138,75 +148,98 @@ private static ClusterState initialState(DiscoveryNode localNode, long term, lon
             .build();
     }
 
-    private void setupFakeMasterServiceAndCoordinator(long term, ClusterState initialState, NodeHealthService nodeHealthService) {
+    private void setupFakeClusterManagerServiceAndCoordinator(long term, ClusterState initialState, NodeHealthService nodeHealthService) {
         deterministicTaskQueue = new DeterministicTaskQueue(
             Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), "test").build(),
             random()
         );
         final ThreadPool fakeThreadPool = deterministicTaskQueue.getThreadPool();
-        FakeThreadPoolMasterService fakeMasterService = new FakeThreadPoolMasterService(
+        FakeThreadPoolClusterManagerService fakeClusterManagerService = new FakeThreadPoolClusterManagerService(
             "test_node",
             "test",
             fakeThreadPool,
             deterministicTaskQueue::scheduleNow
         );
-        setupMasterServiceAndCoordinator(term, initialState, fakeMasterService, fakeThreadPool, Randomness.get(), nodeHealthService);
-        fakeMasterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+        setupClusterManagerServiceAndCoordinator(
+            term,
+            initialState,
+            fakeClusterManagerService,
+            fakeThreadPool,
+            Randomness.get(),
+            nodeHealthService
+        );
+        fakeClusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
             coordinator.handlePublishRequest(new PublishRequest(event.state()));
             publishListener.onResponse(null);
         });
-        fakeMasterService.start();
+        fakeClusterManagerService.start();
     }
 
-    private void setupRealMasterServiceAndCoordinator(long term, ClusterState initialState) {
-        MasterService masterService = new MasterService(
+    private void setupRealClusterManagerServiceAndCoordinator(long term, ClusterState initialState) {
+        ClusterManagerService clusterManagerService = new ClusterManagerService(
             Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), "test_node").build(),
             new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
             threadPool
         );
         AtomicReference<ClusterState> clusterStateRef = new AtomicReference<>(initialState);
-        masterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+        clusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
             clusterStateRef.set(event.state());
             publishListener.onResponse(null);
         });
-        setupMasterServiceAndCoordinator(
+        setupClusterManagerServiceAndCoordinator(
             term,
             initialState,
-            masterService,
+            clusterManagerService,
             threadPool,
             new Random(Randomness.get().nextLong()),
             () -> new StatusInfo(HEALTHY, "healthy-info")
         );
-        masterService.setClusterStateSupplier(clusterStateRef::get);
-        masterService.start();
+        clusterManagerService.setClusterStateSupplier(clusterStateRef::get);
+        clusterManagerService.start();
     }
 
-    private void setupMasterServiceAndCoordinator(
+    private void setupClusterManagerServiceAndCoordinator(
         long term,
         ClusterState initialState,
-        MasterService masterService,
+        ClusterManagerService clusterManagerService,
         ThreadPool threadPool,
         Random random,
         NodeHealthService nodeHealthService
     ) {
-        if (this.masterService != null || coordinator != null) {
-            throw new IllegalStateException("method setupMasterServiceAndCoordinator can only be called once");
+        if (this.clusterManagerService != null || coordinator != null) {
+            throw new IllegalStateException("method setupClusterManagerServiceAndCoordinator can only be called once");
         }
-        this.masterService = masterService;
+        this.clusterManagerService = clusterManagerService;
         CapturingTransport capturingTransport = new CapturingTransport() {
             @Override
             protected void onSendRequest(long requestId, String action, TransportRequest request, DiscoveryNode destination) {
-                if (action.equals(HANDSHAKE_ACTION_NAME)) {
-                    handleResponse(
-                        requestId,
-                        new TransportService.HandshakeResponse(destination, initialState.getClusterName(), destination.getVersion())
-                    );
-                } else if (action.equals(JoinHelper.VALIDATE_JOIN_ACTION_NAME)) {
-                    handleResponse(requestId, new TransportResponse.Empty());
-                } else {
-                    super.onSendRequest(requestId, action, request, destination);
+                switch (action) {
+                    case HANDSHAKE_ACTION_NAME:
+                        handleResponse(
+                            requestId,
+                            new TransportService.HandshakeResponse(destination, initialState.getClusterName(), destination.getVersion())
+                        );
+                        break;
+                    case JoinHelper.VALIDATE_JOIN_ACTION_NAME:
+                    case JoinHelper.VALIDATE_COMPRESSED_JOIN_ACTION_NAME:
+                        handleResponse(requestId, new TransportResponse.Empty());
+                        break;
+                    default:
+                        super.onSendRequest(requestId, action, request, destination);
+                        break;
                 }
             }
+
+            @Override
+            protected void onSendRequest(
+                long requestId,
+                String action,
+                TransportRequest request,
+                DiscoveryNode destination,
+                TransportRequestOptions options
+            ) {
+                onSendRequest(requestId, action, request, destination);
+            }
         };
         final ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
         TransportService transportService = capturingTransport.createTransportService(
@@ -215,8 +248,11 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> initialState.nodes().getLocalNode(),
             clusterSettings,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
+        final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+        persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, new InMemoryPersistedState(term, initialState));
         coordinator = new Coordinator(
             "test_node",
             Settings.EMPTY,
@@ -224,15 +260,17 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             transportService,
             writableRegistry(),
             OpenSearchAllocationTestCase.createAllocationService(Settings.EMPTY),
-            masterService,
-            () -> new InMemoryPersistedState(term, initialState),
+            clusterManagerService,
+            () -> persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL),
             r -> emptyList(),
             new NoOpClusterApplier(),
             Collections.emptyList(),
             random,
             (s, p, r) -> {},
             ElectionStrategy.DEFAULT_INSTANCE,
-            nodeHealthService
+            nodeHealthService,
+            persistedStateRegistry,
+            Mockito.mock(RemoteStoreNodeService.class)
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -245,14 +283,14 @@ protected DiscoveryNode newNode(int i) {
         return newNode(i, randomBoolean());
     }
 
-    protected DiscoveryNode newNode(int i, boolean master) {
+    protected DiscoveryNode newNode(int i, boolean clusterManager) {
         final Set<DiscoveryNodeRole> roles;
-        if (master) {
+        if (clusterManager) {
             roles = singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
         } else {
             roles = Collections.emptySet();
         }
-        final String prefix = master ? "master_" : "data_";
+        final String prefix = clusterManager ? "cluster_manager_" : "data_";
         return new DiscoveryNode(prefix + i, i + "", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
     }
 
@@ -323,23 +361,23 @@ public void testJoinWithHigherTermElectsLeader() {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(randomFrom(node0, node1))),
             () -> new StatusInfo(HEALTHY, "healthy-info")
         );
         assertFalse(isLocalNodeElectedMaster());
-        assertNull(coordinator.getStateForMasterService().nodes().getMasterNodeId());
+        assertNull(coordinator.getStateForClusterManagerService().nodes().getClusterManagerNodeId());
         long newTerm = initialTerm + randomLongBetween(1, 10);
         SimpleFuture fut = joinNodeAsync(
             new JoinRequest(node1, newTerm, Optional.of(new Join(node1, node0, newTerm, initialTerm, initialVersion)))
         );
         assertEquals(Coordinator.Mode.LEADER, coordinator.getMode());
-        assertNull(coordinator.getStateForMasterService().nodes().getMasterNodeId());
+        assertNull(coordinator.getStateForClusterManagerService().nodes().getClusterManagerNodeId());
         deterministicTaskQueue.runAllRunnableTasks();
         assertTrue(fut.isDone());
         assertTrue(isLocalNodeElectedMaster());
-        assertTrue(coordinator.getStateForMasterService().nodes().isLocalNodeElectedMaster());
+        assertTrue(coordinator.getStateForClusterManagerService().nodes().isLocalNodeElectedClusterManager());
     }
 
     public void testJoinWithHigherTermButBetterStateGetsRejected() {
@@ -347,7 +385,7 @@ public void testJoinWithHigherTermButBetterStateGetsRejected() {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node1)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -362,12 +400,12 @@ public void testJoinWithHigherTermButBetterStateGetsRejected() {
         assertFalse(isLocalNodeElectedMaster());
     }
 
-    public void testJoinWithHigherTermButBetterStateStillElectsMasterThroughSelfJoin() {
+    public void testJoinWithHigherTermButBetterStateStillElectsClusterManagerThroughSelfJoin() {
         DiscoveryNode node0 = newNode(0, true);
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -384,7 +422,7 @@ public void testJoinElectedLeader() {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -404,7 +442,7 @@ public void testJoinElectedLeaderWithHigherTerm() {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -426,7 +464,7 @@ public void testJoinAccumulation() {
         DiscoveryNode node2 = newNode(2, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node2)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -458,7 +496,7 @@ public void testJoinFollowerWithHigherTerm() throws Exception {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -481,7 +519,7 @@ public void testJoinUpdateVotingConfigExclusion() throws Exception {
             "knownNodeName"
         );
 
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             buildStateWithVotingConfigExclusion(initialNode, initialTerm, initialVersion, votingConfigExclusion),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -506,14 +544,9 @@ public void testJoinUpdateVotingConfigExclusion() throws Exception {
             )
         );
 
-        assertTrue(
-            MasterServiceTests.discoveryState(masterService)
-                .getVotingConfigExclusions()
-                .stream()
-                .anyMatch(
-                    exclusion -> { return "knownNodeName".equals(exclusion.getNodeName()) && "newNodeId".equals(exclusion.getNodeId()); }
-                )
-        );
+        assertTrue(MasterServiceTests.discoveryState(clusterManagerService).getVotingConfigExclusions().stream().anyMatch(exclusion -> {
+            return "knownNodeName".equals(exclusion.getNodeName()) && "newNodeId".equals(exclusion.getNodeId());
+        }));
     }
 
     private ClusterState buildStateWithVotingConfigExclusion(
@@ -583,7 +616,7 @@ public void testJoinFollowerFails() throws Exception {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -604,7 +637,7 @@ public void testBecomeFollowerFailsPendingJoin() throws Exception {
         DiscoveryNode node1 = newNode(1, true);
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupFakeMasterServiceAndCoordinator(
+        setupFakeClusterManagerServiceAndCoordinator(
             initialTerm,
             initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node1)),
             () -> new StatusInfo(HEALTHY, "healthy-info")
@@ -626,27 +659,31 @@ public void testBecomeFollowerFailsPendingJoin() throws Exception {
     }
 
     public void testConcurrentJoining() {
-        List<DiscoveryNode> masterNodes = IntStream.rangeClosed(1, randomIntBetween(2, 5))
+        List<DiscoveryNode> clusterManagerNodes = IntStream.rangeClosed(1, randomIntBetween(2, 5))
             .mapToObj(nodeId -> newNode(nodeId, true))
             .collect(Collectors.toList());
-        List<DiscoveryNode> otherNodes = IntStream.rangeClosed(masterNodes.size() + 1, masterNodes.size() + 1 + randomIntBetween(0, 5))
-            .mapToObj(nodeId -> newNode(nodeId, false))
-            .collect(Collectors.toList());
-        List<DiscoveryNode> allNodes = Stream.concat(masterNodes.stream(), otherNodes.stream()).collect(Collectors.toList());
+        List<DiscoveryNode> otherNodes = IntStream.rangeClosed(
+            clusterManagerNodes.size() + 1,
+            clusterManagerNodes.size() + 1 + randomIntBetween(0, 5)
+        ).mapToObj(nodeId -> newNode(nodeId, false)).collect(Collectors.toList());
+        List<DiscoveryNode> allNodes = Stream.concat(clusterManagerNodes.stream(), otherNodes.stream()).collect(Collectors.toList());
 
-        DiscoveryNode localNode = masterNodes.get(0);
+        DiscoveryNode localNode = clusterManagerNodes.get(0);
         VotingConfiguration votingConfiguration = new VotingConfiguration(
-            randomValueOtherThan(singletonList(localNode), () -> randomSubsetOf(randomIntBetween(1, masterNodes.size()), masterNodes))
-                .stream()
-                .map(DiscoveryNode::getId)
-                .collect(Collectors.toSet())
+            randomValueOtherThan(
+                singletonList(localNode),
+                () -> randomSubsetOf(randomIntBetween(1, clusterManagerNodes.size()), clusterManagerNodes)
+            ).stream().map(DiscoveryNode::getId).collect(Collectors.toSet())
         );
 
         logger.info("Voting configuration: {}", votingConfiguration);
 
         long initialTerm = randomLongBetween(1, 10);
         long initialVersion = randomLongBetween(1, 10);
-        setupRealMasterServiceAndCoordinator(initialTerm, initialState(localNode, initialTerm, initialVersion, votingConfiguration));
+        setupRealClusterManagerServiceAndCoordinator(
+            initialTerm,
+            initialState(localNode, initialTerm, initialVersion, votingConfiguration)
+        );
         long newTerm = initialTerm + randomLongBetween(1, 10);
 
         // we need at least a quorum of voting nodes with a correct term and worse state
@@ -735,18 +772,108 @@ public void testConcurrentJoining() {
             throw new RuntimeException(e);
         }
 
-        assertTrue(MasterServiceTests.discoveryState(masterService).nodes().isLocalNodeElectedMaster());
+        assertTrue(MasterServiceTests.discoveryState(clusterManagerService).nodes().isLocalNodeElectedMaster());
         for (DiscoveryNode successfulNode : successfulNodes) {
             assertTrue(successfulNode + " joined cluster", clusterStateHasNode(successfulNode));
-            assertFalse(successfulNode + " voted for master", coordinator.missingJoinVoteFrom(successfulNode));
+            assertFalse(successfulNode + " voted for cluster-manager", coordinator.missingJoinVoteFrom(successfulNode));
         }
     }
 
+    // Validate the deprecated MASTER_ROLE can join another node and elected as leader.
+    public void testJoinElectedLeaderWithDeprecatedMasterRole() {
+        final Set<DiscoveryNodeRole> roles = singleton(DiscoveryNodeRole.MASTER_ROLE);
+        DiscoveryNode node0 = new DiscoveryNode("master0", "0", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
+        DiscoveryNode node1 = new DiscoveryNode("master1", "1", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
+        long initialTerm = 1;
+        long initialVersion = 1;
+        setupFakeClusterManagerServiceAndCoordinator(
+            initialTerm,
+            initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
+            () -> new StatusInfo(HEALTHY, "healthy-info")
+        );
+        assertFalse(isLocalNodeElectedMaster());
+        long newTerm = 2;
+        joinNodeAndRun(new JoinRequest(node0, newTerm, Optional.of(new Join(node0, node0, newTerm, initialTerm, initialVersion))));
+        assertTrue(isLocalNodeElectedMaster());
+        assertFalse(clusterStateHasNode(node1));
+        joinNodeAndRun(new JoinRequest(node1, newTerm, Optional.of(new Join(node1, node0, newTerm, initialTerm, initialVersion))));
+        assertTrue(isLocalNodeElectedMaster());
+        assertTrue(clusterStateHasNode(node1));
+    }
+
+    public void testJoinFailsWhenDecommissioned() {
+        DiscoveryNode node0 = newNode(0, true);
+        DiscoveryNode node1 = newNode(1, true);
+        long initialTerm = randomLongBetween(1, 10);
+        long initialVersion = randomLongBetween(1, 10);
+        setupFakeClusterManagerServiceAndCoordinator(
+            initialTerm,
+            initialStateWithDecommissionedAttribute(
+                initialState(node0, initialTerm, initialVersion, VotingConfiguration.of(node0)),
+                new DecommissionAttribute("zone", "zone1")
+            ),
+            () -> new StatusInfo(HEALTHY, "healthy-info")
+        );
+        assertFalse(isLocalNodeElectedMaster());
+        long newTerm = initialTerm + randomLongBetween(1, 10);
+        joinNodeAndRun(new JoinRequest(node0, newTerm, Optional.of(new Join(node0, node0, newTerm, initialTerm, initialVersion))));
+        assertTrue(isLocalNodeElectedMaster());
+        assertFalse(clusterStateHasNode(node1));
+        joinNodeAndRun(new JoinRequest(node1, newTerm, Optional.of(new Join(node1, node0, newTerm, initialTerm, initialVersion))));
+        assertTrue(isLocalNodeElectedMaster());
+        assertTrue(clusterStateHasNode(node1));
+        DiscoveryNode decommissionedNode = new DiscoveryNode(
+            "data_2",
+            2 + "",
+            buildNewFakeTransportAddress(),
+            Collections.singletonMap("zone", "zone1"),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        long anotherTerm = newTerm + randomLongBetween(1, 10);
+
+        assertThat(
+            expectThrows(
+                NodeDecommissionedException.class,
+                () -> joinNodeAndRun(new JoinRequest(decommissionedNode, anotherTerm, Optional.empty()))
+            ).getMessage(),
+            containsString("with current status of decommissioning")
+        );
+        assertFalse(clusterStateHasNode(decommissionedNode));
+
+        DiscoveryNode node3 = new DiscoveryNode(
+            "data_3",
+            3 + "",
+            buildNewFakeTransportAddress(),
+            Collections.singletonMap("zone", "zone2"),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        long termForNode3 = anotherTerm + randomLongBetween(1, 10);
+
+        joinNodeAndRun(new JoinRequest(node3, termForNode3, Optional.empty()));
+        assertTrue(clusterStateHasNode(node3));
+    }
+
     private boolean isLocalNodeElectedMaster() {
-        return MasterServiceTests.discoveryState(masterService).nodes().isLocalNodeElectedMaster();
+        return MasterServiceTests.discoveryState(clusterManagerService).nodes().isLocalNodeElectedMaster();
     }
 
     private boolean clusterStateHasNode(DiscoveryNode node) {
-        return node.equals(MasterServiceTests.discoveryState(masterService).nodes().get(node.getId()));
+        return node.equals(MasterServiceTests.discoveryState(clusterManagerService).nodes().get(node.getId()));
+    }
+
+    private static ClusterState initialStateWithDecommissionedAttribute(
+        ClusterState clusterState,
+        DecommissionAttribute decommissionAttribute
+    ) {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.SUCCESSFUL,
+            randomAlphaOfLength(10)
+        );
+        return ClusterState.builder(clusterState)
+            .metadata(Metadata.builder(clusterState.metadata()).decommissionAttributeMetadata(decommissionAttributeMetadata))
+            .build();
     }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/OpenSearchNodeCommandTests.java b/server/src/test/java/org/opensearch/cluster/coordination/OpenSearchNodeCommandTests.java
index e88633fbf9399..8358a397bf1b7 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/OpenSearchNodeCommandTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/OpenSearchNodeCommandTests.java
@@ -38,18 +38,18 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.List;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.file.Path;
+import java.util.List;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/PreVoteCollectorTests.java b/server/src/test/java/org/opensearch/cluster/coordination/PreVoteCollectorTests.java
index d399a9296746e..5ddf614db3334 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/PreVoteCollectorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/PreVoteCollectorTests.java
@@ -35,11 +35,13 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.monitor.StatusInfo;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.transport.ConnectTransportException;
@@ -135,7 +137,8 @@ public void handleRemoteError(long requestId, Throwable t) {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundTransportAddress -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -290,10 +293,16 @@ public void testPrevotingIndicatesElectionSuccess() {
         DiscoveryNode[] votingNodes = votingNodesSet.toArray(new DiscoveryNode[0]);
         startAndRunCollector(votingNodes);
 
+        PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+        persistedStateRegistry.addPersistedState(
+            PersistedStateType.LOCAL,
+            new InMemoryPersistedState(currentTerm, makeClusterState(votingNodes))
+        );
         final CoordinationState coordinationState = new CoordinationState(
             localNode,
-            new InMemoryPersistedState(currentTerm, makeClusterState(votingNodes)),
-            ElectionStrategy.DEFAULT_INSTANCE
+            persistedStateRegistry,
+            ElectionStrategy.DEFAULT_INSTANCE,
+            Settings.EMPTY
         );
 
         final long newTerm = randomLongBetween(currentTerm + 1, Long.MAX_VALUE);
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/PublicationTests.java b/server/src/test/java/org/opensearch/cluster/coordination/PublicationTests.java
index 954e8ce79cdc8..4d18ff95887dd 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/PublicationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/PublicationTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.cluster.coordination;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -44,10 +44,11 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -91,11 +92,9 @@ class MockNode {
                 CoordinationMetadata.VotingConfiguration.EMPTY_CONFIG,
                 0L
             );
-            coordinationState = new CoordinationState(
-                localNode,
-                new InMemoryPersistedState(0L, initialState),
-                ElectionStrategy.DEFAULT_INSTANCE
-            );
+            PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+            persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, new InMemoryPersistedState(0L, initialState));
+            coordinationState = new CoordinationState(localNode, persistedStateRegistry, ElectionStrategy.DEFAULT_INSTANCE, Settings.EMPTY);
         }
 
         final DiscoveryNode localNode;
@@ -447,7 +446,7 @@ public void testClusterStatePublishingFailsOrTimesOutBeforeCommit() throws Inter
             );
     }
 
-    public void testPublishingToMastersFirst() {
+    public void testPublishingToClusterManagersFirst() {
         VotingConfiguration singleNodeConfig = VotingConfiguration.of(n1);
         initializeCluster(singleNodeConfig);
 
@@ -462,7 +461,7 @@ public void testPublishingToMastersFirst() {
 
         List<DiscoveryNode> publicationTargets = new ArrayList<>(publication.pendingPublications.keySet());
         List<DiscoveryNode> sortedPublicationTargets = new ArrayList<>(publicationTargets);
-        Collections.sort(sortedPublicationTargets, Comparator.comparing(n -> n.isMasterNode() == false));
+        Collections.sort(sortedPublicationTargets, Comparator.comparing(n -> n.isClusterManagerNode() == false));
         assertEquals(sortedPublicationTargets, publicationTargets);
     }
 
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/PublicationTransportHandlerTests.java b/server/src/test/java/org/opensearch/cluster/coordination/PublicationTransportHandlerTests.java
index 658b8155919d8..6d94054afdea2 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/PublicationTransportHandlerTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/PublicationTransportHandlerTests.java
@@ -39,10 +39,11 @@
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.node.Node;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.transport.TransportService;
@@ -68,7 +69,8 @@ public void testDiffSerializationFailure() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> localNode,
             clusterSettings,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         final PublicationTransportHandler handler = new PublicationTransportHandler(
             transportService,
diff --git a/server/src/test/java/org/opensearch/cluster/coordination/ReconfiguratorTests.java b/server/src/test/java/org/opensearch/cluster/coordination/ReconfiguratorTests.java
index 71d640e202f33..057455fefc4b3 100644
--- a/server/src/test/java/org/opensearch/cluster/coordination/ReconfiguratorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/coordination/ReconfiguratorTests.java
@@ -223,14 +223,14 @@ private void check(
         boolean autoShrinkVotingConfiguration,
         VotingConfiguration expectedConfig
     ) {
-        final DiscoveryNode master = liveNodes.stream().sorted(Comparator.comparing(DiscoveryNode::getId)).findFirst().get();
-        check(liveNodes, retired, master.getId(), config, autoShrinkVotingConfiguration, expectedConfig);
+        final DiscoveryNode clusterManager = liveNodes.stream().sorted(Comparator.comparing(DiscoveryNode::getId)).findFirst().get();
+        check(liveNodes, retired, clusterManager.getId(), config, autoShrinkVotingConfiguration, expectedConfig);
     }
 
     private void check(
         Set<DiscoveryNode> liveNodes,
         Set<String> retired,
-        String masterId,
+        String clusterManagerId,
         VotingConfiguration config,
         boolean autoShrinkVotingConfiguration,
         VotingConfiguration expectedConfig
@@ -239,14 +239,14 @@ private void check(
             Settings.builder().put(CLUSTER_AUTO_SHRINK_VOTING_CONFIGURATION.getKey(), autoShrinkVotingConfiguration).build()
         );
 
-        final DiscoveryNode master = liveNodes.stream().filter(n -> n.getId().equals(masterId)).findFirst().get();
-        final VotingConfiguration adaptedConfig = reconfigurator.reconfigure(liveNodes, retired, master, config);
+        final DiscoveryNode clusterManager = liveNodes.stream().filter(n -> n.getId().equals(clusterManagerId)).findFirst().get();
+        final VotingConfiguration adaptedConfig = reconfigurator.reconfigure(liveNodes, retired, clusterManager, config);
         assertEquals(
             new ParameterizedMessage(
-                "[liveNodes={}, retired={}, master={}, config={}, autoShrinkVotingConfiguration={}]",
+                "[liveNodes={}, retired={}, clusterManager={}, config={}, autoShrinkVotingConfiguration={}]",
                 liveNodes,
                 retired,
-                master,
+                clusterManager,
                 config,
                 autoShrinkVotingConfiguration
             ).getFormattedMessage(),
diff --git a/server/src/test/java/org/opensearch/cluster/decommission/DecommissionControllerTests.java b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionControllerTests.java
new file mode 100644
index 0000000000000..627f31502a417
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionControllerTests.java
@@ -0,0 +1,309 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.OpenSearchTimeoutException;
+import org.opensearch.Version;
+import org.opensearch.action.admin.cluster.configuration.TransportAddVotingConfigExclusionsAction;
+import org.opensearch.action.admin.cluster.configuration.TransportClearVotingConfigExclusionsAction;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.ClusterState.builder;
+import static org.opensearch.cluster.OpenSearchAllocationTestCase.createAllocationService;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+import static org.opensearch.test.ClusterServiceUtils.setState;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.notNullValue;
+
+public class DecommissionControllerTests extends OpenSearchTestCase {
+
+    private static ThreadPool threadPool;
+    private static ClusterService clusterService;
+    private TransportService transportService;
+    private AllocationService allocationService;
+    private DecommissionController decommissionController;
+    private ClusterSettings clusterSettings;
+
+    @Before
+    public void setTransportServiceAndDefaultClusterState() {
+        threadPool = new TestThreadPool("test", Settings.EMPTY);
+        allocationService = createAllocationService();
+        ClusterState clusterState = ClusterState.builder(new ClusterName("test")).build();
+        logger.info("--> adding five nodes on same zone_1");
+        clusterState = addNodes(clusterState, "zone_1", "node1", "node2", "node3", "node4", "node5");
+        logger.info("--> adding five nodes on same zone_2");
+        clusterState = addNodes(clusterState, "zone_2", "node6", "node7", "node8", "node9", "node10");
+        logger.info("--> adding five nodes on same zone_3");
+        clusterState = addNodes(clusterState, "zone_3", "node11", "node12", "node13", "node14", "node15");
+        clusterState = setLocalNodeAsClusterManagerNode(clusterState, "node1");
+        clusterState = setThreeNodesInVotingConfig(clusterState);
+        final ClusterState.Builder builder = builder(clusterState);
+        clusterService = createClusterService(threadPool, clusterState.nodes().get("node1"));
+        setState(clusterService, builder);
+        final MockTransport transport = new MockTransport();
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundTransportAddress -> clusterService.state().nodes().get("node1"),
+            null,
+            emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+        final Settings.Builder nodeSettingsBuilder = Settings.builder();
+        final Settings nodeSettings = nodeSettingsBuilder.build();
+        clusterSettings = new ClusterSettings(nodeSettings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+        new TransportAddVotingConfigExclusionsAction(
+            nodeSettings,
+            clusterSettings,
+            transportService,
+            clusterService,
+            threadPool,
+            new ActionFilters(emptySet()),
+            new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY))
+        ); // registers action
+
+        new TransportClearVotingConfigExclusionsAction(
+            transportService,
+            clusterService,
+            threadPool,
+            new ActionFilters(emptySet()),
+            new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY))
+        ); // registers action
+
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        decommissionController = new DecommissionController(clusterService, transportService, allocationService, threadPool);
+    }
+
+    @After
+    public void shutdownThreadPoolAndClusterService() {
+        clusterService.stop();
+        threadPool.shutdown();
+    }
+
+    public void testNodesRemovedForDecommissionRequestSuccessfulResponse() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        Set<DiscoveryNode> nodesToBeRemoved = new HashSet<>();
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node11"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node12"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node13"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node14"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node15"));
+
+        decommissionController.removeDecommissionedNodes(
+            nodesToBeRemoved,
+            "unit-test",
+            TimeValue.timeValueSeconds(30L),
+            new ActionListener<Void>() {
+                @Override
+                public void onResponse(Void unused) {
+                    countDownLatch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    fail("there shouldn't have been any failure");
+                }
+            }
+        );
+
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        // test all 5 nodes removed and cluster has 10 nodes
+        Set<DiscoveryNode> nodes = StreamSupport.stream(clusterService.getClusterApplierService().state().nodes().spliterator(), false)
+            .collect(Collectors.toSet());
+        assertEquals(nodes.size(), 10);
+        // test no nodes part of zone-3
+        for (DiscoveryNode node : nodes) {
+            assertNotEquals(node.getAttributes().get("zone"), "zone-1");
+        }
+    }
+
+    public void testTimesOut() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        Set<DiscoveryNode> nodesToBeRemoved = new HashSet<>();
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node11"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node12"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node13"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node14"));
+        nodesToBeRemoved.add(clusterService.state().nodes().get("node15"));
+        final AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        decommissionController.removeDecommissionedNodes(
+            nodesToBeRemoved,
+            "unit-test-timeout",
+            TimeValue.timeValueMillis(0),
+            new ActionListener<>() {
+                @Override
+                public void onResponse(Void unused) {
+                    countDownLatch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    exceptionReference.set(e);
+                    countDownLatch.countDown();
+                }
+            }
+        );
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        MatcherAssert.assertThat("Expected onFailure to be called", exceptionReference.get(), notNullValue());
+        MatcherAssert.assertThat(exceptionReference.get(), instanceOf(OpenSearchTimeoutException.class));
+        MatcherAssert.assertThat(exceptionReference.get().getMessage(), containsString("waiting for removal of decommissioned nodes"));
+    }
+
+    public void testSuccessfulDecommissionStatusMetadataUpdate() throws InterruptedException {
+        Map<DecommissionStatus, Set<DecommissionStatus>> decommissionStateTransitionMap = Map.of(
+            DecommissionStatus.INIT,
+            Set.of(DecommissionStatus.DRAINING, DecommissionStatus.IN_PROGRESS),
+            DecommissionStatus.DRAINING,
+            Set.of(DecommissionStatus.IN_PROGRESS),
+            DecommissionStatus.IN_PROGRESS,
+            Set.of(DecommissionStatus.SUCCESSFUL)
+        );
+
+        for (Map.Entry<DecommissionStatus, Set<DecommissionStatus>> entry : decommissionStateTransitionMap.entrySet()) {
+            for (DecommissionStatus val : entry.getValue()) {
+                verifyDecommissionStatusTransition(entry.getKey(), val);
+            }
+        }
+    }
+
+    public void testSuccessfulDecommissionStatusMetadataUpdateForFailedState() throws InterruptedException {
+        Map<DecommissionStatus, Set<DecommissionStatus>> decommissionStateTransitionMap = Map.of(
+            DecommissionStatus.INIT,
+            Set.of(DecommissionStatus.FAILED),
+            DecommissionStatus.DRAINING,
+            Set.of(DecommissionStatus.FAILED),
+            DecommissionStatus.IN_PROGRESS,
+            Set.of(DecommissionStatus.FAILED)
+        );
+
+        for (Map.Entry<DecommissionStatus, Set<DecommissionStatus>> entry : decommissionStateTransitionMap.entrySet()) {
+            for (DecommissionStatus val : entry.getValue()) {
+                verifyDecommissionStatusTransition(entry.getKey(), val);
+            }
+        }
+    }
+
+    private void verifyDecommissionStatusTransition(DecommissionStatus currentStatus, DecommissionStatus newStatus)
+        throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionAttributeMetadata oldMetadata = new DecommissionAttributeMetadata(
+            new DecommissionAttribute("zone", "zone-1"),
+            currentStatus,
+            randomAlphaOfLength(10)
+        );
+        ClusterState state = clusterService.state();
+        Metadata metadata = state.metadata();
+        Metadata.Builder mdBuilder = Metadata.builder(metadata);
+        mdBuilder.decommissionAttributeMetadata(oldMetadata);
+        state = ClusterState.builder(state).metadata(mdBuilder).build();
+        setState(clusterService, state);
+
+        decommissionController.updateMetadataWithDecommissionStatus(newStatus, new ActionListener<DecommissionStatus>() {
+            @Override
+            public void onResponse(DecommissionStatus status) {
+                assertEquals(newStatus, status);
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("decommission status update failed");
+                countDownLatch.countDown();
+            }
+        });
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        ClusterState newState = clusterService.getClusterApplierService().state();
+        DecommissionAttributeMetadata decommissionAttributeMetadata = newState.metadata().decommissionAttributeMetadata();
+        assertEquals(decommissionAttributeMetadata.status(), newStatus);
+    }
+
+    private ClusterState addNodes(ClusterState clusterState, String zone, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds).forEach(nodeId -> nodeBuilder.add(newNode(nodeId, singletonMap("zone", zone))));
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setLocalNodeAsClusterManagerNode(ClusterState clusterState, String nodeId) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        nodeBuilder.localNodeId(nodeId);
+        nodeBuilder.clusterManagerNodeId(nodeId);
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setThreeNodesInVotingConfig(ClusterState clusterState) {
+        final CoordinationMetadata.VotingConfiguration votingConfiguration = CoordinationMetadata.VotingConfiguration.of(
+            clusterState.nodes().get("node1"),
+            clusterState.nodes().get("node6"),
+            clusterState.nodes().get("node11")
+        );
+
+        Metadata.Builder builder = Metadata.builder()
+            .coordinationMetadata(
+                CoordinationMetadata.builder()
+                    .lastAcceptedConfiguration(votingConfiguration)
+                    .lastCommittedConfiguration(votingConfiguration)
+                    .build()
+            );
+        clusterState = ClusterState.builder(clusterState).metadata(builder).build();
+        return clusterState;
+    }
+
+    private static DiscoveryNode newNode(String nodeId, Map<String, String> attributes) {
+        return new DiscoveryNode(nodeId, nodeId, buildNewFakeTransportAddress(), attributes, CLUSTER_MANAGER_DATA_ROLE, Version.CURRENT);
+    }
+
+    final private static Set<DiscoveryNodeRole> CLUSTER_MANAGER_DATA_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE, DiscoveryNodeRole.DATA_ROLE))
+    );
+}
diff --git a/server/src/test/java/org/opensearch/cluster/decommission/DecommissionHelperTests.java b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionHelperTests.java
new file mode 100644
index 0000000000000..15821cdb3335b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionHelperTests.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.BeforeClass;
+
+import java.util.Set;
+
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singleton;
+import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.decommission.DecommissionHelper.addVotingConfigExclusionsForNodesToBeDecommissioned;
+import static org.opensearch.cluster.decommission.DecommissionHelper.deleteDecommissionAttributeInClusterState;
+import static org.opensearch.cluster.decommission.DecommissionHelper.filterNodesWithDecommissionAttribute;
+import static org.opensearch.cluster.decommission.DecommissionHelper.nodeCommissioned;
+import static org.opensearch.cluster.decommission.DecommissionHelper.registerDecommissionAttributeInClusterState;
+
+public class DecommissionHelperTests extends OpenSearchTestCase {
+
+    private static DiscoveryNode node1, node2, node3, dataNode;
+    private static ClusterState initialClusterState;
+
+    public void testRegisterAndDeleteDecommissionAttributeInClusterState() {
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone2");
+        ClusterState updatedState = registerDecommissionAttributeInClusterState(
+            initialClusterState,
+            decommissionAttribute,
+            randomAlphaOfLength(10)
+        );
+        assertEquals(decommissionAttribute, updatedState.metadata().decommissionAttributeMetadata().decommissionAttribute());
+        updatedState = deleteDecommissionAttributeInClusterState(updatedState);
+        assertNull(updatedState.metadata().decommissionAttributeMetadata());
+    }
+
+    public void testAddVotingConfigExclusionsForNodesToBeDecommissioned() {
+        Set<String> nodeIdToBeExcluded = Set.of("node2");
+        ClusterState updatedState = addVotingConfigExclusionsForNodesToBeDecommissioned(
+            initialClusterState,
+            nodeIdToBeExcluded,
+            TimeValue.timeValueMinutes(1),
+            10
+        );
+        CoordinationMetadata.VotingConfigExclusion v1 = new CoordinationMetadata.VotingConfigExclusion(node2);
+        assertTrue(
+            updatedState.coordinationMetadata().getVotingConfigExclusions().contains(new CoordinationMetadata.VotingConfigExclusion(node2))
+        );
+        assertEquals(1, updatedState.coordinationMetadata().getVotingConfigExclusions().size());
+    }
+
+    public void testFilterNodes() {
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone1");
+        Set<DiscoveryNode> filteredNodes = filterNodesWithDecommissionAttribute(initialClusterState, decommissionAttribute, true);
+        assertTrue(filteredNodes.contains(node1));
+        assertEquals(1, filteredNodes.size());
+        filteredNodes = filterNodesWithDecommissionAttribute(initialClusterState, decommissionAttribute, false);
+        assertTrue(filteredNodes.contains(node1));
+        assertTrue(filteredNodes.contains(dataNode));
+        assertEquals(2, filteredNodes.size());
+    }
+
+    public void testNodeCommissioned() {
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone1");
+        DecommissionStatus decommissionStatus = randomFrom(
+            DecommissionStatus.IN_PROGRESS,
+            DecommissionStatus.DRAINING,
+            DecommissionStatus.SUCCESSFUL
+        );
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            decommissionStatus,
+            randomAlphaOfLength(10)
+        );
+        Metadata metadata = Metadata.builder().putCustom(DecommissionAttributeMetadata.TYPE, decommissionAttributeMetadata).build();
+        assertTrue(nodeCommissioned(node2, metadata));
+        assertFalse(nodeCommissioned(node1, metadata));
+        DecommissionStatus commissionStatus = randomFrom(DecommissionStatus.FAILED, DecommissionStatus.INIT);
+        decommissionAttributeMetadata = new DecommissionAttributeMetadata(decommissionAttribute, commissionStatus, randomAlphaOfLength(10));
+        metadata = Metadata.builder().putCustom(DecommissionAttributeMetadata.TYPE, decommissionAttributeMetadata).build();
+        assertTrue(nodeCommissioned(node2, metadata));
+        assertTrue(nodeCommissioned(node1, metadata));
+        metadata = Metadata.builder().removeCustom(DecommissionAttributeMetadata.TYPE).build();
+        assertTrue(nodeCommissioned(node2, metadata));
+        assertTrue(nodeCommissioned(node1, metadata));
+    }
+
+    @BeforeClass
+    public static void createBaseClusterState() {
+        node1 = makeDiscoveryNode("node1", "zone1");
+        node2 = makeDiscoveryNode("node2", "zone2");
+        node3 = makeDiscoveryNode("node3", "zone3");
+        dataNode = new DiscoveryNode(
+            "data",
+            "data",
+            buildNewFakeTransportAddress(),
+            singletonMap("zone", "zone1"),
+            emptySet(),
+            Version.CURRENT
+        );
+        final CoordinationMetadata.VotingConfiguration allNodesConfig = CoordinationMetadata.VotingConfiguration.of(node1, node2, node3);
+        initialClusterState = ClusterState.builder(new ClusterName("cluster"))
+            .nodes(
+                new DiscoveryNodes.Builder().add(node1)
+                    .add(node2)
+                    .add(node3)
+                    .add(dataNode)
+                    .localNodeId(node1.getId())
+                    .clusterManagerNodeId(node1.getId())
+            )
+            .metadata(
+                Metadata.builder()
+                    .coordinationMetadata(
+                        CoordinationMetadata.builder()
+                            .lastAcceptedConfiguration(allNodesConfig)
+                            .lastCommittedConfiguration(allNodesConfig)
+                            .build()
+                    )
+            )
+            .build();
+    }
+
+    private static DiscoveryNode makeDiscoveryNode(String name, String zone) {
+        return new DiscoveryNode(
+            name,
+            name,
+            buildNewFakeTransportAddress(),
+            singletonMap("zone", zone),
+            singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/decommission/DecommissionServiceTests.java b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionServiceTests.java
new file mode 100644
index 0000000000000..3ead45a0f42fe
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/decommission/DecommissionServiceTests.java
@@ -0,0 +1,483 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.decommission;
+
+import org.opensearch.Version;
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateResponse;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionResponse;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.mockito.Mockito;
+
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.ClusterState.builder;
+import static org.opensearch.cluster.OpenSearchAllocationTestCase.createAllocationService;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+import static org.opensearch.test.ClusterServiceUtils.setState;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.notNullValue;
+
+public class DecommissionServiceTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private AllocationService allocationService;
+    private DecommissionService decommissionService;
+    private ClusterSettings clusterSettings;
+
+    @Before
+    public void setUpService() {
+        threadPool = new TestThreadPool("test", Settings.EMPTY);
+        clusterService = createClusterService(threadPool);
+        allocationService = createAllocationService();
+        ClusterState clusterState = ClusterState.builder(new ClusterName("test")).build();
+        logger.info("--> adding cluster manager node on zone_1");
+        clusterState = addClusterManagerNodes(clusterState, "zone_1", "node1");
+        logger.info("--> adding cluster manager node on zone_2");
+        clusterState = addClusterManagerNodes(clusterState, "zone_2", "node6");
+        logger.info("--> adding cluster manager node on zone_3");
+        clusterState = addClusterManagerNodes(clusterState, "zone_3", "node11");
+        logger.info("--> adding four data nodes on zone_1");
+        clusterState = addDataNodes(clusterState, "zone_1", "node2", "node3", "node4", "node5");
+        logger.info("--> adding four data nodes on zone_2");
+        clusterState = addDataNodes(clusterState, "zone_2", "node7", "node8", "node9", "node10");
+        logger.info("--> adding four data nodes on zone_3");
+        clusterState = addDataNodes(clusterState, "zone_3", "node12", "node13", "node14", "node15");
+        clusterState = setLocalNodeAsClusterManagerNode(clusterState, "node1");
+        clusterState = setNodesInVotingConfig(
+            clusterState,
+            clusterState.nodes().get("node1"),
+            clusterState.nodes().get("node6"),
+            clusterState.nodes().get("node11")
+        );
+        final ClusterState.Builder builder = builder(clusterState);
+        setState(clusterService, builder);
+        final MockTransport transport = new MockTransport();
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundTransportAddress -> clusterService.state().nodes().get("node1"),
+            null,
+            emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+        final Settings.Builder nodeSettingsBuilder = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "zone_1,zone_2,zone_3");
+
+        clusterSettings = new ClusterSettings(nodeSettingsBuilder.build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        this.decommissionService = new DecommissionService(
+            nodeSettingsBuilder.build(),
+            clusterSettings,
+            clusterService,
+            transportService,
+            threadPool,
+            allocationService
+        );
+    }
+
+    @After
+    public void shutdownThreadPoolAndClusterService() {
+        clusterService.stop();
+        threadPool.shutdown();
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testDecommissioningNotStartedForInvalidAttributeName() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("rack", "rack-a");
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof DecommissioningFailedException);
+                assertThat(e.getMessage(), Matchers.endsWith("invalid awareness attribute requested for decommissioning"));
+                countDownLatch.countDown();
+            }
+        };
+        decommissionService.startDecommissionAction(new DecommissionRequest(decommissionAttribute), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testDecommissionNotStartedWithoutWeighingAwayAttribute_1() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_1", 1.0, "zone_2", 1.0, "zone_3", 0.0);
+        setWeightedRoutingWeights(weights);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone_1");
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof DecommissioningFailedException);
+                assertThat(
+                    e.getMessage(),
+                    Matchers.containsString("weight for decommissioned attribute is expected to be [0.0] but found [1.0]")
+                );
+                countDownLatch.countDown();
+            }
+        };
+        decommissionService.startDecommissionAction(new DecommissionRequest(decommissionAttribute), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testDecommissionNotStartedWithoutWeighingAwayAttribute_2() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone_1");
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof DecommissioningFailedException);
+                assertThat(
+                    e.getMessage(),
+                    Matchers.containsString(
+                        "no weights are set to the attribute. Please set appropriate weights before triggering decommission action"
+                    )
+                );
+                countDownLatch.countDown();
+            }
+        };
+        decommissionService.startDecommissionAction(new DecommissionRequest(decommissionAttribute), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testExternalDecommissionRetryNotAllowed() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionStatus oldStatus = DecommissionStatus.INIT;
+        DecommissionAttributeMetadata oldMetadata = new DecommissionAttributeMetadata(
+            new DecommissionAttribute("zone", "zone_1"),
+            oldStatus,
+            randomAlphaOfLength(10)
+        );
+        final ClusterState.Builder builder = builder(clusterService.state());
+        setState(
+            clusterService,
+            builder.metadata(Metadata.builder(clusterService.state().metadata()).decommissionAttributeMetadata(oldMetadata).build())
+        );
+        AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionReference.set(e);
+                countDownLatch.countDown();
+            }
+        };
+        DecommissionRequest request = new DecommissionRequest(new DecommissionAttribute("zone", "zone_1"));
+        decommissionService.startDecommissionAction(request, listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        MatcherAssert.assertThat("Expected onFailure to be called", exceptionReference.get(), notNullValue());
+        MatcherAssert.assertThat(exceptionReference.get(), instanceOf(DecommissioningFailedException.class));
+        MatcherAssert.assertThat(exceptionReference.get().getMessage(), containsString("same request is already in status [INIT]"));
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testDecommissioningFailedWhenAnotherAttributeDecommissioningSuccessful() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionStatus oldStatus = randomFrom(DecommissionStatus.SUCCESSFUL, DecommissionStatus.IN_PROGRESS, DecommissionStatus.INIT);
+        DecommissionAttributeMetadata oldMetadata = new DecommissionAttributeMetadata(
+            new DecommissionAttribute("zone", "zone_1"),
+            oldStatus,
+            randomAlphaOfLength(10)
+        );
+        final ClusterState.Builder builder = builder(clusterService.state());
+        setState(
+            clusterService,
+            builder.metadata(Metadata.builder(clusterService.state().metadata()).decommissionAttributeMetadata(oldMetadata).build())
+        );
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof DecommissioningFailedException);
+                if (oldStatus.equals(DecommissionStatus.SUCCESSFUL)) {
+                    assertThat(
+                        e.getMessage(),
+                        Matchers.endsWith("already successfully decommissioned, recommission before triggering another decommission")
+                    );
+                } else {
+                    assertThat(e.getMessage(), Matchers.endsWith("is in progress, cannot process this request"));
+                }
+                countDownLatch.countDown();
+            }
+        };
+        DecommissionRequest request = new DecommissionRequest(new DecommissionAttribute("zone", "zone_2"));
+        decommissionService.startDecommissionAction(request, listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testDecommissioningFailedWhenAnotherRequestForSameAttributeIsExecuted() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionStatus oldStatus = DecommissionStatus.INIT;
+        DecommissionAttributeMetadata oldMetadata = new DecommissionAttributeMetadata(
+            new DecommissionAttribute("zone", "zone_1"),
+            oldStatus,
+            randomAlphaOfLength(10)
+        );
+        final ClusterState.Builder builder = builder(clusterService.state());
+        setState(
+            clusterService,
+            builder.metadata(Metadata.builder(clusterService.state().metadata()).decommissionAttributeMetadata(oldMetadata).build())
+        );
+        AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<DecommissionResponse> listener = new ActionListener<DecommissionResponse>() {
+            @Override
+            public void onResponse(DecommissionResponse decommissionResponse) {
+                fail("on response shouldn't have been called");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof DecommissioningFailedException);
+                exceptionReference.set(e);
+                countDownLatch.countDown();
+            }
+        };
+        DecommissionRequest request = new DecommissionRequest(new DecommissionAttribute("zone", "zone_1"));
+        decommissionService.startDecommissionAction(request, listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        assertTrue(exceptionReference.get() instanceof DecommissioningFailedException);
+        assertThat(exceptionReference.get().getMessage(), Matchers.endsWith("same request is already in status [INIT]"));
+    }
+
+    public void testScheduleNodesDecommissionOnTimeout() {
+        TransportService mockTransportService = Mockito.mock(TransportService.class);
+        ThreadPool mockThreadPool = Mockito.mock(ThreadPool.class);
+        Mockito.when(mockTransportService.getLocalNode()).thenReturn(Mockito.mock(DiscoveryNode.class));
+        Mockito.when(mockTransportService.getThreadPool()).thenReturn(mockThreadPool);
+        DecommissionService decommissionService = new DecommissionService(
+            Settings.EMPTY,
+            clusterSettings,
+            clusterService,
+            mockTransportService,
+            threadPool,
+            allocationService
+        );
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-2");
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.DRAINING,
+            randomAlphaOfLength(10)
+        );
+        Metadata metadata = Metadata.builder().putCustom(DecommissionAttributeMetadata.TYPE, decommissionAttributeMetadata).build();
+        ClusterState state = ClusterState.builder(new ClusterName("test")).metadata(metadata).build();
+
+        DiscoveryNode decommissionedNode1 = Mockito.mock(DiscoveryNode.class);
+        DiscoveryNode decommissionedNode2 = Mockito.mock(DiscoveryNode.class);
+
+        setState(clusterService, state);
+        decommissionService.scheduleNodesDecommissionOnTimeout(
+            Set.of(decommissionedNode1, decommissionedNode2),
+            DecommissionRequest.DEFAULT_NODE_DRAINING_TIMEOUT
+        );
+
+        Mockito.verify(mockThreadPool).schedule(Mockito.any(Runnable.class), Mockito.any(TimeValue.class), Mockito.anyString());
+    }
+
+    public void testDrainNodesWithDecommissionedAttributeWithNoDelay() {
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-2");
+        String requestID = randomAlphaOfLength(10);
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.INIT,
+            requestID
+        );
+
+        Metadata metadata = Metadata.builder().putCustom(DecommissionAttributeMetadata.TYPE, decommissionAttributeMetadata).build();
+        ClusterState state = ClusterState.builder(new ClusterName("test")).metadata(metadata).build();
+
+        DecommissionRequest request = new DecommissionRequest(decommissionAttribute);
+        request.setNoDelay(true);
+        request.setRequestID(requestID);
+
+        setState(clusterService, state);
+        decommissionService.drainNodesWithDecommissionedAttribute(request);
+
+    }
+
+    public void testRecommissionAction() throws InterruptedException {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone-2");
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            DecommissionStatus.SUCCESSFUL,
+            randomAlphaOfLength(10)
+        );
+        final ClusterState.Builder builder = builder(clusterService.state());
+        setState(
+            clusterService,
+            builder.metadata(
+                Metadata.builder(clusterService.state().metadata())
+                    .decommissionAttributeMetadata(decommissionAttributeMetadata)
+                    .coordinationMetadata(
+                        CoordinationMetadata.builder()
+                            .addVotingConfigExclusion(
+                                new CoordinationMetadata.VotingConfigExclusion(clusterService.state().nodes().get("node6"))
+                            )
+                            .build()
+                    )
+                    .build()
+            )
+        );
+        AtomicReference<ClusterState> clusterStateAtomicReference = new AtomicReference<>();
+
+        ActionListener<DeleteDecommissionStateResponse> listener = new ActionListener<>() {
+            @Override
+            public void onResponse(DeleteDecommissionStateResponse decommissionResponse) {
+                clusterStateAtomicReference.set(clusterService.state());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("on failure shouldn't have been called");
+                countDownLatch.countDown();
+            }
+        };
+        this.decommissionService.startRecommissionAction(listener);
+        // Decommission Attribute should be removed.
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        assertNull(clusterStateAtomicReference.get().metadata().decommissionAttributeMetadata());
+        assertEquals(0, clusterStateAtomicReference.get().coordinationMetadata().getVotingConfigExclusions().size());
+    }
+
+    private void setWeightedRoutingWeights(Map<String, Double> weights) {
+        ClusterState clusterState = clusterService.state();
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+        ClusterState.Builder builder = ClusterState.builder(clusterState);
+        ClusterServiceUtils.setState(clusterService, builder);
+    }
+
+    private ClusterState addDataNodes(ClusterState clusterState, String zone, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds).forEach(nodeId -> nodeBuilder.add(newDataNode(nodeId, singletonMap("zone", zone))));
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState addClusterManagerNodes(ClusterState clusterState, String zone, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds).forEach(nodeId -> nodeBuilder.add(newClusterManagerNode(nodeId, singletonMap("zone", zone))));
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setLocalNodeAsClusterManagerNode(ClusterState clusterState, String nodeId) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        nodeBuilder.localNodeId(nodeId);
+        nodeBuilder.clusterManagerNodeId(nodeId);
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setNodesInVotingConfig(ClusterState clusterState, DiscoveryNode... nodes) {
+        final CoordinationMetadata.VotingConfiguration votingConfiguration = CoordinationMetadata.VotingConfiguration.of(nodes);
+
+        Metadata.Builder builder = Metadata.builder()
+            .coordinationMetadata(
+                CoordinationMetadata.builder()
+                    .lastAcceptedConfiguration(votingConfiguration)
+                    .lastCommittedConfiguration(votingConfiguration)
+                    .build()
+            );
+        clusterState = ClusterState.builder(clusterState).metadata(builder).build();
+        return clusterState;
+    }
+
+    private static DiscoveryNode newDataNode(String nodeId, Map<String, String> attributes) {
+        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), attributes, DATA_ROLE, Version.CURRENT);
+    }
+
+    private static DiscoveryNode newClusterManagerNode(String nodeId, Map<String, String> attributes) {
+        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), attributes, CLUSTER_MANAGER_ROLE, Version.CURRENT);
+    }
+
+    final private static Set<DiscoveryNodeRole> CLUSTER_MANAGER_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+    );
+
+    final private static Set<DiscoveryNodeRole> DATA_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.DATA_ROLE))
+    );
+
+    private ClusterState removeNodes(ClusterState clusterState, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.getNodes());
+        List.of(nodeIds).forEach(nodeBuilder::remove);
+        return allocationService.disassociateDeadNodes(ClusterState.builder(clusterState).nodes(nodeBuilder).build(), false, "test");
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/health/ClusterHealthAllocationTests.java b/server/src/test/java/org/opensearch/cluster/health/ClusterHealthAllocationTests.java
index 2f05297146f8e..06e58672fa994 100644
--- a/server/src/test/java/org/opensearch/cluster/health/ClusterHealthAllocationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/health/ClusterHealthAllocationTests.java
@@ -85,10 +85,13 @@ public void testClusterHealth() {
         assertEquals(ClusterHealthStatus.GREEN, getClusterHealthStatus(clusterState));
     }
 
-    private ClusterState addNode(ClusterState clusterState, String nodeName, boolean isMaster) {
+    private ClusterState addNode(ClusterState clusterState, String nodeName, boolean isClusterManager) {
         DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.getNodes());
         nodeBuilder.add(
-            newNode(nodeName, Collections.singleton(isMaster ? DiscoveryNodeRole.CLUSTER_MANAGER_ROLE : DiscoveryNodeRole.DATA_ROLE))
+            newNode(
+                nodeName,
+                Collections.singleton(isClusterManager ? DiscoveryNodeRole.CLUSTER_MANAGER_ROLE : DiscoveryNodeRole.DATA_ROLE)
+            )
         );
         return ClusterState.builder(clusterState).nodes(nodeBuilder).build();
     }
diff --git a/server/src/test/java/org/opensearch/cluster/health/ClusterIndexHealthTests.java b/server/src/test/java/org/opensearch/cluster/health/ClusterIndexHealthTests.java
index dddc299c68e69..557f7f74db7a7 100644
--- a/server/src/test/java/org/opensearch/cluster/health/ClusterIndexHealthTests.java
+++ b/server/src/test/java/org/opensearch/cluster/health/ClusterIndexHealthTests.java
@@ -36,9 +36,9 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.IndexRoutingTable;
 import org.opensearch.cluster.routing.RoutingTableGenerator;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/health/ClusterShardHealthTests.java b/server/src/test/java/org/opensearch/cluster/health/ClusterShardHealthTests.java
index 7b78a78617c27..734ad4058630d 100644
--- a/server/src/test/java/org/opensearch/cluster/health/ClusterShardHealthTests.java
+++ b/server/src/test/java/org/opensearch/cluster/health/ClusterShardHealthTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.cluster.health;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/health/ClusterStateHealthTests.java b/server/src/test/java/org/opensearch/cluster/health/ClusterStateHealthTests.java
index 9a6c458edeb11..795dc8a624e38 100644
--- a/server/src/test/java/org/opensearch/cluster/health/ClusterStateHealthTests.java
+++ b/server/src/test/java/org/opensearch/cluster/health/ClusterStateHealthTests.java
@@ -31,8 +31,6 @@
 
 package org.opensearch.cluster.health;
 
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -56,12 +54,12 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 import org.opensearch.test.transport.CapturingTransport;
@@ -76,8 +74,10 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
@@ -118,7 +118,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -144,7 +145,7 @@ public void testClusterHealthWaitsForClusterStateApplication() throws Interrupte
         setState(
             clusterService,
             ClusterState.builder(clusterService.state())
-                .nodes(DiscoveryNodes.builder(clusterService.state().nodes()).masterNodeId(null))
+                .nodes(DiscoveryNodes.builder(clusterService.state().nodes()).clusterManagerNodeId(null))
                 .build()
         );
 
@@ -157,13 +158,13 @@ public void testClusterHealthWaitsForClusterStateApplication() throws Interrupte
             }
         });
 
-        logger.info("--> submit task to restore master");
+        logger.info("--> submit task to restore cluster-manager");
         ClusterState currentState = clusterService.getClusterApplierService().state();
         clusterService.getClusterApplierService()
             .onNewClusterState(
-                "restore master",
+                "restore cluster-manager",
                 () -> ClusterState.builder(currentState)
-                    .nodes(DiscoveryNodes.builder(currentState.nodes()).masterNodeId(currentState.nodes().getLocalNodeId()))
+                    .nodes(DiscoveryNodes.builder(currentState.nodes()).clusterManagerNodeId(currentState.nodes().getLocalNodeId()))
                     .build(),
                 (source, e) -> {}
             );
@@ -177,14 +178,15 @@ public void testClusterHealthWaitsForClusterStateApplication() throws Interrupte
             threadPool,
             new ActionFilters(new HashSet<>()),
             indexNameExpressionResolver,
-            new AllocationService(null, new TestGatewayAllocator(), null, null, null)
+            new AllocationService(null, new TestGatewayAllocator(), null, null, null),
+            null
         );
         PlainActionFuture<ClusterHealthResponse> listener = new PlainActionFuture<>();
         action.execute(new ClusterHealthRequest().waitForGreenStatus(), listener);
 
         assertFalse(listener.isDone());
 
-        logger.info("--> realising task to restore master");
+        logger.info("--> realising task to restore cluster-manager");
         applyLatch.countDown();
         listener.get();
     }
@@ -219,7 +221,10 @@ public void testClusterHealth() throws IOException {
         ClusterStateHealth clusterStateHealth = new ClusterStateHealth(clusterState, concreteIndices);
         logger.info("cluster status: {}, expected {}", clusterStateHealth.getStatus(), counter.status());
         clusterStateHealth = maybeSerialize(clusterStateHealth);
-        assertThat(clusterStateHealth.hasDiscoveredMaster(), equalTo(clusterService.state().nodes().getMasterNodeId() != null));
+        assertThat(
+            clusterStateHealth.hasDiscoveredClusterManager(),
+            equalTo(clusterService.state().nodes().getClusterManagerNodeId() != null)
+        );
         assertClusterHealth(clusterStateHealth, counter);
     }
 
@@ -412,8 +417,8 @@ private List<ClusterState> generateClusterStates(
         RoutingTable routingTable = originalClusterState.routingTable();
         IndexRoutingTable indexRoutingTable = routingTable.index(indexName);
         IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary()) {
                     newIndexRoutingTable.addShard(shardRouting.initialize(randomFrom(nodeIds), null, shardRouting.getExpectedShardSize()));
@@ -429,13 +434,13 @@ private List<ClusterState> generateClusterStates(
         // some primaries started
         indexRoutingTable = routingTable.index(indexName);
         newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        ImmutableOpenIntMap.Builder<Set<String>> allocationIds = ImmutableOpenIntMap.<Set<String>>builder();
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        Map<Integer, Set<String>> allocationIds = new HashMap<>();
+        for (var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary() && randomBoolean()) {
                     final ShardRouting newShardRouting = shardRouting.moveToStarted();
-                    allocationIds.fPut(newShardRouting.getId(), Sets.newHashSet(newShardRouting.allocationId().getId()));
+                    allocationIds.put(newShardRouting.getId(), Set.of(newShardRouting.allocationId().getId()));
                     newIndexRoutingTable.addShard(newShardRouting);
                 } else {
                     newIndexRoutingTable.addShard(shardRouting);
@@ -443,10 +448,8 @@ private List<ClusterState> generateClusterStates(
             }
         }
         routingTable = RoutingTable.builder(routingTable).add(newIndexRoutingTable).build();
-        IndexMetadata.Builder idxMetaBuilder = IndexMetadata.builder(clusterState.metadata().index(indexName));
-        for (final IntObjectCursor<Set<String>> entry : allocationIds.build()) {
-            idxMetaBuilder.putInSyncAllocationIds(entry.key, entry.value);
-        }
+        final IndexMetadata.Builder idxMetaBuilder = IndexMetadata.builder(clusterState.metadata().index(indexName));
+        allocationIds.forEach(idxMetaBuilder::putInSyncAllocationIds);
         Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata()).put(idxMetaBuilder);
         clusterState = ClusterState.builder(clusterState).routingTable(routingTable).metadata(metadataBuilder).build();
         clusterStates.add(clusterState);
@@ -456,8 +459,8 @@ private List<ClusterState> generateClusterStates(
             // some primaries failed to allocate
             indexRoutingTable = routingTable.index(indexName);
             newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-            for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-                final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+            for (final var shardEntry : indexRoutingTable.getShards().values()) {
+                final IndexShardRoutingTable shardRoutingTable = shardEntry;
                 for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                     if (shardRouting.primary() && (shardRouting.started() == false || alreadyFailedPrimary == false)) {
                         newIndexRoutingTable.addShard(
@@ -477,13 +480,13 @@ private List<ClusterState> generateClusterStates(
         // all primaries started
         indexRoutingTable = routingTable.index(indexName);
         newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        allocationIds = ImmutableOpenIntMap.<Set<String>>builder();
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        allocationIds = new HashMap<>();
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary() && shardRouting.started() == false) {
                     final ShardRouting newShardRouting = shardRouting.moveToStarted();
-                    allocationIds.fPut(newShardRouting.getId(), Sets.newHashSet(newShardRouting.allocationId().getId()));
+                    allocationIds.put(newShardRouting.getId(), Set.of(newShardRouting.allocationId().getId()));
                     newIndexRoutingTable.addShard(newShardRouting);
                 } else {
                     newIndexRoutingTable.addShard(shardRouting);
@@ -491,19 +494,17 @@ private List<ClusterState> generateClusterStates(
             }
         }
         routingTable = RoutingTable.builder(routingTable).add(newIndexRoutingTable).build();
-        idxMetaBuilder = IndexMetadata.builder(clusterState.metadata().index(indexName));
-        for (final IntObjectCursor<Set<String>> entry : allocationIds.build()) {
-            idxMetaBuilder.putInSyncAllocationIds(entry.key, entry.value);
-        }
-        metadataBuilder = Metadata.builder(clusterState.metadata()).put(idxMetaBuilder);
+        final IndexMetadata.Builder idxMetaBuilder2 = IndexMetadata.builder(clusterState.metadata().index(indexName));
+        allocationIds.forEach(idxMetaBuilder2::putInSyncAllocationIds);
+        metadataBuilder = Metadata.builder(clusterState.metadata()).put(idxMetaBuilder2);
         clusterState = ClusterState.builder(clusterState).routingTable(routingTable).metadata(metadataBuilder).build();
         clusterStates.add(clusterState);
 
         // initialize replicas
         indexRoutingTable = routingTable.index(indexName);
         newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             final String primaryNodeId = shardRoutingTable.primaryShard().currentNodeId();
             Set<String> allocatedNodes = new HashSet<>();
             allocatedNodes.add(primaryNodeId);
@@ -524,8 +525,8 @@ private List<ClusterState> generateClusterStates(
         // some replicas started
         indexRoutingTable = routingTable.index(indexName);
         newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary() == false && randomBoolean()) {
                     newIndexRoutingTable.addShard(shardRouting.moveToStarted());
@@ -541,8 +542,8 @@ private List<ClusterState> generateClusterStates(
         boolean replicaStateChanged = false;
         indexRoutingTable = routingTable.index(indexName);
         newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-        for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-            final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+        for (final var shardEntry : indexRoutingTable.getShards().values()) {
+            final IndexShardRoutingTable shardRoutingTable = shardEntry;
             for (final ShardRouting shardRouting : shardRoutingTable.getShards()) {
                 if (shardRouting.primary() == false && shardRouting.started() == false) {
                     newIndexRoutingTable.addShard(shardRouting.moveToStarted());
@@ -564,10 +565,10 @@ private List<ClusterState> generateClusterStates(
     // returns true if the inactive primaries in the index are only due to cluster recovery
     // (not because of allocation of existing shard or previously having allocation ids assigned)
     private boolean primaryInactiveDueToRecovery(final String indexName, final ClusterState clusterState) {
-        for (final IntObjectCursor<IndexShardRoutingTable> shardRouting : clusterState.routingTable().index(indexName).shards()) {
-            final ShardRouting primaryShard = shardRouting.value.primaryShard();
+        for (final var shardRouting : clusterState.routingTable().index(indexName).shards().entrySet()) {
+            final ShardRouting primaryShard = shardRouting.getValue().primaryShard();
             if (primaryShard.active() == false) {
-                if (clusterState.metadata().index(indexName).inSyncAllocationIds(shardRouting.key).isEmpty() == false) {
+                if (clusterState.metadata().index(indexName).inSyncAllocationIds(shardRouting.getKey()).isEmpty() == false) {
                     return false;
                 }
                 if (primaryShard.recoverySource() != null
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/AliasMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/AliasMetadataTests.java
index df3055db9d568..2d57626917247 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/AliasMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/AliasMetadataTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.cluster.metadata.AliasMetadata.Builder;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/AutoExpandReplicasTests.java b/server/src/test/java/org/opensearch/cluster/metadata/AutoExpandReplicasTests.java
index d6c62e4bb0903..d06ec8a32e552 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/AutoExpandReplicasTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/AutoExpandReplicasTests.java
@@ -146,7 +146,7 @@ public void testAutoExpandWhenNodeLeavesAndPossiblyRejoins() throws InterruptedE
 
         try {
             List<DiscoveryNode> allNodes = new ArrayList<>();
-            DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the master
+            DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the cluster-manager
             allNodes.add(localNode);
             int numDataNodes = randomIntBetween(3, 5);
             List<DiscoveryNode> dataNodes = new ArrayList<>(numDataNodes);
@@ -190,7 +190,7 @@ public void testAutoExpandWhenNodeLeavesAndPossiblyRejoins() throws InterruptedE
                 assertThat(postTable.toString(), postTable.getAllAllocationIds(), everyItem(is(in(preTable.getAllAllocationIds()))));
             } else {
                 // fake an election where conflicting nodes are removed and readded
-                state = ClusterState.builder(state).nodes(DiscoveryNodes.builder(state.nodes()).masterNodeId(null).build()).build();
+                state = ClusterState.builder(state).nodes(DiscoveryNodes.builder(state.nodes()).clusterManagerNodeId(null).build()).build();
 
                 List<DiscoveryNode> conflictingNodes = randomSubsetOf(2, dataNodes);
                 unchangedNodeIds = dataNodes.stream()
@@ -215,7 +215,7 @@ public void testAutoExpandWhenNodeLeavesAndPossiblyRejoins() throws InterruptedE
                     nodesToAdd.add(createNode(DiscoveryNodeRole.DATA_ROLE));
                 }
 
-                state = cluster.joinNodesAndBecomeMaster(state, nodesToAdd);
+                state = cluster.joinNodesAndBecomeClusterManager(state, nodesToAdd);
                 postTable = state.routingTable().index("index").shard(0);
             }
 
@@ -247,7 +247,7 @@ public void testOnlyAutoExpandAllocationFilteringAfterAllNodesUpgraded() {
                 VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_1),
                 DiscoveryNodeRole.CLUSTER_MANAGER_ROLE,
                 DiscoveryNodeRole.DATA_ROLE
-            ); // local node is the master
+            ); // local node is the cluster-manager
             allNodes.add(oldNode);
             ClusterState state = ClusterStateCreationUtils.state(oldNode, oldNode, allNodes.toArray(new DiscoveryNode[0]));
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateMetadataTests.java
index d04150186aee7..66e00d320dd40 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateMetadataTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.test.AbstractNamedWriteableTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateTests.java
index 7bd72bb29c036..67e84a27f2eb9 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ComponentTemplateTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractDiffableSerializationTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadataTests.java
index 83ad6c40cc7b2..f6161fb2b62cc 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateMetadataTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.test.AbstractNamedWriteableTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateTests.java
index f709b36a7cb01..1e56970ea5bb5 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ComposableIndexTemplateTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractDiffableSerializationTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamMetadataTests.java
index fcef13d034767..17daae49d5ab5 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamMetadataTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.test.AbstractNamedWriteableTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTemplateTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTemplateTests.java
index 23afc23c80279..ed2bb01672900 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTemplateTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTemplateTests.java
@@ -11,9 +11,9 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.ComposableIndexTemplate.DataStreamTemplate;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTests.java
index 53a2ae8528729..a70438307f94a 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DataStreamTests.java
@@ -32,9 +32,9 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataSerializationTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataSerializationTests.java
new file mode 100644
index 0000000000000..e9502a04450f4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataSerializationTests.java
@@ -0,0 +1,88 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.cluster.ClusterModule;
+import org.opensearch.cluster.Diff;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractDiffableSerializationTestCase;
+
+import java.io.IOException;
+
+public class DecommissionAttributeMetadataSerializationTests extends AbstractDiffableSerializationTestCase<Metadata.Custom> {
+
+    @Override
+    protected Writeable.Reader<Metadata.Custom> instanceReader() {
+        return DecommissionAttributeMetadata::new;
+    }
+
+    @Override
+    protected Metadata.Custom createTestInstance() {
+        String attributeName = randomAlphaOfLength(6);
+        String attributeValue = randomAlphaOfLength(6);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+        DecommissionStatus decommissionStatus = randomFrom(DecommissionStatus.values());
+        return new DecommissionAttributeMetadata(decommissionAttribute, decommissionStatus, randomAlphaOfLength(10));
+    }
+
+    @Override
+    protected Metadata.Custom mutateInstance(Metadata.Custom instance) {
+        return randomValueOtherThan(instance, this::createTestInstance);
+    }
+
+    @Override
+    protected Metadata.Custom makeTestChanges(Metadata.Custom testInstance) {
+        DecommissionAttributeMetadata decommissionAttributeMetadata = (DecommissionAttributeMetadata) testInstance;
+        DecommissionAttribute decommissionAttribute = decommissionAttributeMetadata.decommissionAttribute();
+        String attributeName = decommissionAttribute.attributeName();
+        String attributeValue = decommissionAttribute.attributeValue();
+        DecommissionStatus decommissionStatus = decommissionAttributeMetadata.status();
+        if (randomBoolean()) {
+            decommissionStatus = randomFrom(DecommissionStatus.values());
+        }
+        if (randomBoolean()) {
+            attributeName = randomAlphaOfLength(6);
+        }
+        if (randomBoolean()) {
+            attributeValue = randomAlphaOfLength(6);
+        }
+        return new DecommissionAttributeMetadata(
+            new DecommissionAttribute(attributeName, attributeValue),
+            decommissionStatus,
+            randomAlphaOfLength(10)
+        );
+    }
+
+    @Override
+    protected Writeable.Reader<Diff<Metadata.Custom>> diffReader() {
+        return DecommissionAttributeMetadata::readDiffFrom;
+    }
+
+    @Override
+    protected NamedWriteableRegistry getNamedWriteableRegistry() {
+        return new NamedWriteableRegistry(ClusterModule.getNamedWriteables());
+    }
+
+    @Override
+    protected Metadata.Custom doParseInstance(XContentParser parser) throws IOException {
+        assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
+        DecommissionAttributeMetadata decommissionAttributeMetadata = DecommissionAttributeMetadata.fromXContent(parser);
+        assertEquals(XContentParser.Token.END_OBJECT, parser.currentToken());
+        return new DecommissionAttributeMetadata(
+            decommissionAttributeMetadata.decommissionAttribute(),
+            decommissionAttributeMetadata.status(),
+            decommissionAttributeMetadata.requestID()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataTests.java
new file mode 100644
index 0000000000000..d3259dea0d289
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataTests.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.test.AbstractNamedWriteableTestCase;
+
+import java.io.IOException;
+import java.util.Collections;
+
+public class DecommissionAttributeMetadataTests extends AbstractNamedWriteableTestCase<DecommissionAttributeMetadata> {
+    @Override
+    protected DecommissionAttributeMetadata createTestInstance() {
+        String attributeName = randomAlphaOfLength(6);
+        String attributeValue = randomAlphaOfLength(6);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+        DecommissionStatus decommissionStatus = randomFrom(DecommissionStatus.values());
+        return new DecommissionAttributeMetadata(decommissionAttribute, decommissionStatus, randomAlphaOfLength(10));
+    }
+
+    @Override
+    protected DecommissionAttributeMetadata mutateInstance(DecommissionAttributeMetadata instance) throws IOException {
+        return randomValueOtherThan(instance, this::createTestInstance);
+    }
+
+    @Override
+    protected NamedWriteableRegistry getNamedWriteableRegistry() {
+        return new NamedWriteableRegistry(
+            Collections.singletonList(
+                new NamedWriteableRegistry.Entry(
+                    DecommissionAttributeMetadata.class,
+                    DecommissionAttributeMetadata.TYPE,
+                    DecommissionAttributeMetadata::new
+                )
+            )
+        );
+    }
+
+    @Override
+    protected Class<DecommissionAttributeMetadata> categoryClass() {
+        return DecommissionAttributeMetadata.class;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataXContentTests.java b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataXContentTests.java
new file mode 100644
index 0000000000000..557ec83f57325
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/metadata/DecommissionAttributeMetadataXContentTests.java
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+
+public class DecommissionAttributeMetadataXContentTests extends AbstractXContentTestCase<DecommissionAttributeMetadata> {
+    @Override
+    protected DecommissionAttributeMetadata createTestInstance() {
+        String attributeName = randomAlphaOfLength(6);
+        String attributeValue = randomAlphaOfLength(6);
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute(attributeName, attributeValue);
+        DecommissionStatus decommissionStatus = randomFrom(DecommissionStatus.values());
+        return new DecommissionAttributeMetadata(decommissionAttribute, decommissionStatus, randomAlphaOfLength(10));
+    }
+
+    @Override
+    protected DecommissionAttributeMetadata doParseInstance(XContentParser parser) throws IOException {
+        return DecommissionAttributeMetadata.fromXContent(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return false;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/IndexGraveyardTests.java b/server/src/test/java/org/opensearch/cluster/metadata/IndexGraveyardTests.java
index c27f803ab8980..d33048afef4fc 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/IndexGraveyardTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/IndexGraveyardTests.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentOpenSearchExtension;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -86,7 +87,7 @@ public void testXContent() throws IOException {
         if (graveyard.getTombstones().size() > 0) {
             // check that date properly printed
             assertThat(
-                Strings.toString(graveyard, false, true),
+                Strings.toString(MediaTypeRegistry.JSON, graveyard, false, true),
                 containsString(
                     XContentOpenSearchExtension.DEFAULT_DATE_PRINTER.print(graveyard.getTombstones().get(0).getDeleteDateInMillis())
                 )
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/IndexMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/IndexMetadataTests.java
index 87860b8c536ef..393a652952771 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/IndexMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/IndexMetadataTests.java
@@ -36,22 +36,22 @@
 import org.opensearch.action.admin.indices.rollover.MaxDocsCondition;
 import org.opensearch.action.admin.indices.rollover.MaxSizeCondition;
 import org.opensearch.action.admin.indices.rollover.RolloverInfo;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
@@ -128,7 +128,10 @@ public void testIndexMetadataSerialization() throws IOException {
         XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(builder));
         final IndexMetadata fromXContentMeta = IndexMetadata.fromXContent(parser);
         assertEquals(
-            "expected: " + Strings.toString(metadata) + "\nactual  : " + Strings.toString(fromXContentMeta),
+            "expected: "
+                + Strings.toString(MediaTypeRegistry.JSON, metadata)
+                + "\nactual  : "
+                + Strings.toString(MediaTypeRegistry.JSON, fromXContentMeta),
             metadata,
             fromXContentMeta
         );
@@ -142,9 +145,7 @@ public void testIndexMetadataSerialization() throws IOException {
         assertEquals(metadata.getRoutingFactor(), fromXContentMeta.getRoutingFactor());
         assertEquals(metadata.primaryTerm(0), fromXContentMeta.primaryTerm(0));
         assertEquals(metadata.isSystem(), fromXContentMeta.isSystem());
-        ImmutableOpenMap.Builder<String, DiffableStringMap> expectedCustomBuilder = ImmutableOpenMap.builder();
-        expectedCustomBuilder.put("my_custom", new DiffableStringMap(customMap));
-        ImmutableOpenMap<String, DiffableStringMap> expectedCustom = expectedCustomBuilder.build();
+        final Map<String, DiffableStringMap> expectedCustom = Map.of("my_custom", new DiffableStringMap(customMap));
         assertEquals(metadata.getCustomData(), expectedCustom);
         assertEquals(metadata.getCustomData(), fromXContentMeta.getCustomData());
 
@@ -227,6 +228,25 @@ public void testSelectShrinkShards() {
         );
     }
 
+    public void testSelectCloneShard() {
+        int numberOfReplicas = randomIntBetween(0, 10);
+        IndexMetadata metadata = IndexMetadata.builder("foo")
+            .settings(
+                Settings.builder()
+                    .put("index.version.created", 1)
+                    .put("index.number_of_shards", 10)
+                    .put("index.number_of_replicas", numberOfReplicas)
+                    .build()
+            )
+            .creationDate(randomLong())
+            .build();
+
+        assertEquals(
+            "the number of target shards (11) must be the same as the number of source shards (10)",
+            expectThrows(IllegalArgumentException.class, () -> IndexMetadata.selectCloneShard(0, metadata, 11)).getMessage()
+        );
+    }
+
     public void testSelectResizeShards() {
         int numTargetShards = randomFrom(4, 6, 8, 12);
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/IndexNameExpressionResolverTests.java b/server/src/test/java/org/opensearch/cluster/metadata/IndexNameExpressionResolverTests.java
index e736e27e5aa44..51696ca599d02 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/IndexNameExpressionResolverTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/IndexNameExpressionResolverTests.java
@@ -45,10 +45,10 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata.State;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.IndexClosedException;
@@ -2020,14 +2020,7 @@ public void testIndicesAliasesRequestTargetDataStreams() {
 
         Metadata.Builder mdBuilder = Metadata.builder()
             .put(backingIndex, false)
-            .put(
-                new DataStream(
-                    dataStreamName,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(backingIndex.getIndex()),
-                    1
-                )
-            );
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(backingIndex.getIndex()), 1));
         ClusterState state = ClusterState.builder(new ClusterName("_name")).metadata(mdBuilder).build();
 
         {
@@ -2248,14 +2241,7 @@ public void testDataStreams() {
         Metadata.Builder mdBuilder = Metadata.builder()
             .put(index1, false)
             .put(index2, false)
-            .put(
-                new DataStream(
-                    dataStreamName,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(index1.getIndex(), index2.getIndex()),
-                    2
-                )
-            );
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(index1.getIndex(), index2.getIndex()), 2));
         ClusterState state = ClusterState.builder(new ClusterName("_name")).metadata(mdBuilder).build();
 
         {
@@ -2347,20 +2333,8 @@ public void testDataStreamsWithWildcardExpression() {
             .put(index2, false)
             .put(index3, false)
             .put(index4, false)
-            .put(
-                new DataStream(
-                    dataStream1,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(index1.getIndex(), index2.getIndex())
-                )
-            )
-            .put(
-                new DataStream(
-                    dataStream2,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(index3.getIndex(), index4.getIndex())
-                )
-            );
+            .put(new DataStream(dataStream1, createTimestampField("@timestamp"), List.of(index1.getIndex(), index2.getIndex())))
+            .put(new DataStream(dataStream2, createTimestampField("@timestamp"), List.of(index3.getIndex(), index4.getIndex())));
 
         ClusterState state = ClusterState.builder(new ClusterName("_name")).metadata(mdBuilder).build();
         {
@@ -2417,20 +2391,8 @@ public void testDataStreamsWithClosedBackingIndicesAndWildcardExpressions() {
             .put(index2, false)
             .put(index3, false)
             .put(index4, false)
-            .put(
-                new DataStream(
-                    dataStream1,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(index1.getIndex(), index2.getIndex())
-                )
-            )
-            .put(
-                new DataStream(
-                    dataStream2,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(index3.getIndex(), index4.getIndex())
-                )
-            );
+            .put(new DataStream(dataStream1, createTimestampField("@timestamp"), List.of(index1.getIndex(), index2.getIndex())))
+            .put(new DataStream(dataStream2, createTimestampField("@timestamp"), List.of(index3.getIndex(), index4.getIndex())));
 
         ClusterState state = ClusterState.builder(new ClusterName("_name")).metadata(mdBuilder).build();
         IndicesOptions indicesOptions = IndicesOptions.STRICT_EXPAND_OPEN;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/IndexTemplateMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/IndexTemplateMetadataTests.java
index fb5537b5292ba..0ea2834cc3024 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/IndexTemplateMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/IndexTemplateMetadataTests.java
@@ -31,23 +31,23 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Map;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.Matchers.contains;
@@ -73,7 +73,7 @@ public void testIndexTemplateMetadataXContentRoundTrip() throws Exception {
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 templateBytes,
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             indexTemplateMetadata = IndexTemplateMetadata.Builder.fromXContent(parser, "test");
@@ -93,7 +93,7 @@ public void testIndexTemplateMetadataXContentRoundTrip() throws Exception {
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 templateBytesRoundTrip,
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             indexTemplateMetadataRoundTrip = IndexTemplateMetadata.Builder.fromXContent(parser, "test");
@@ -109,8 +109,8 @@ public void testValidateInvalidIndexPatterns() throws Exception {
                 randomInt(),
                 Collections.emptyList(),
                 Settings.EMPTY,
-                ImmutableOpenMap.of(),
-                ImmutableOpenMap.of()
+                Map.of(),
+                Map.of()
             );
         });
         assertThat(emptyPatternError.getMessage(), equalTo("Index patterns must not be null or empty; got []"));
@@ -122,8 +122,8 @@ public void testValidateInvalidIndexPatterns() throws Exception {
                 randomInt(),
                 null,
                 Settings.EMPTY,
-                ImmutableOpenMap.of(),
-                ImmutableOpenMap.of()
+                Map.of(),
+                Map.of()
             );
         });
         assertThat(nullPatternError.getMessage(), equalTo("Index patterns must not be null or empty; got null"));
@@ -142,7 +142,7 @@ public void testValidateInvalidIndexPatterns() throws Exception {
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 new BytesArray(templateWithEmptyPattern),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             final IllegalArgumentException ex = expectThrows(
@@ -166,7 +166,7 @@ public void testValidateInvalidIndexPatterns() throws Exception {
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 new BytesArray(templateWithoutPattern),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             final IllegalArgumentException ex = expectThrows(
@@ -184,7 +184,7 @@ public void testParseTemplateWithAliases() throws Exception {
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
                 new BytesArray(templateInJSON),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         ) {
             IndexTemplateMetadata template = IndexTemplateMetadata.Builder.fromXContent(parser, randomAlphaOfLengthBetween(1, 100));
@@ -222,7 +222,7 @@ public void testFromToXContent() throws Exception {
             templateBuilder.putMapping("doc", "{\"doc\":{\"properties\":{\"type\":\"text\"}}}");
         }
         IndexTemplateMetadata template = templateBuilder.build();
-        XContentBuilder builder = XContentBuilder.builder(randomFrom(XContentType.JSON.xContent()));
+        XContentBuilder builder = XContentBuilder.builder(randomFrom(MediaTypeRegistry.JSON.xContent()));
         builder.startObject();
         IndexTemplateMetadata.Builder.toXContentWithTypes(template, builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ManifestTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ManifestTests.java
index 8acffb7771517..5b1a96c02ac4e 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ManifestTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ManifestTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataCreateIndexServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataCreateIndexServiceTests.java
index 5bea69c5bbd66..bb3b579fa25ba 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataCreateIndexServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataCreateIndexServiceTests.java
@@ -32,9 +32,6 @@
 
 package org.opensearch.cluster.metadata;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
-import org.hamcrest.Matchers;
-import org.junit.Before;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.ResourceAlreadyExistsException;
@@ -52,32 +49,36 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.MaxRetryAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.compress.CompressedXContent;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.InvalidAliasNameException;
 import org.opensearch.indices.InvalidIndexNameException;
 import org.opensearch.indices.ShardLimitValidator;
 import org.opensearch.indices.SystemIndexDescriptor;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
@@ -85,6 +86,9 @@
 import org.opensearch.test.gateway.TestGatewayAllocator;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.hamcrest.Matchers;
+import org.junit.After;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -95,7 +99,9 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -109,21 +115,16 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singleton;
 import static java.util.Collections.singletonList;
-import static org.opensearch.index.IndexSettings.INDEX_SOFT_DELETES_SETTING;
-import static org.hamcrest.Matchers.endsWith;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.hasKey;
-import static org.hamcrest.Matchers.hasValue;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
-import static org.hamcrest.Matchers.startsWith;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_NUMBER_OF_ROUTING_SHARDS_SETTING;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_READ_ONLY_BLOCK;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_READ_ONLY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.opensearch.cluster.metadata.MetadataCreateIndexService.aggregateIndexSettings;
 import static org.opensearch.cluster.metadata.MetadataCreateIndexService.buildIndexMetadata;
@@ -131,13 +132,45 @@
 import static org.opensearch.cluster.metadata.MetadataCreateIndexService.getIndexNumberOfRoutingShards;
 import static org.opensearch.cluster.metadata.MetadataCreateIndexService.parseV1Mappings;
 import static org.opensearch.cluster.metadata.MetadataCreateIndexService.resolveAndValidateAliases;
+import static org.opensearch.index.IndexSettings.INDEX_REFRESH_INTERVAL_SETTING;
+import static org.opensearch.index.IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING;
+import static org.opensearch.index.IndexSettings.INDEX_SOFT_DELETES_SETTING;
+import static org.opensearch.index.IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING;
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
 import static org.opensearch.indices.ShardLimitValidatorTests.createTestShardLimitService;
+import static org.opensearch.node.Node.NODE_ATTRIBUTES;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.hamcrest.Matchers.endsWith;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasKey;
+import static org.hamcrest.Matchers.hasValue;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.Matchers.startsWith;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class MetadataCreateIndexServiceTests extends OpenSearchTestCase {
 
     private AliasValidator aliasValidator;
     private CreateIndexClusterStateUpdateRequest request;
     private QueryShardContext queryShardContext;
+    private ClusterSettings clusterSettings;
+    private static final String segmentRepositoryNameAttributeKey = NODE_ATTRIBUTES.getKey()
+        + REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+    private static final String translogRepositoryNameAttributeKey = NODE_ATTRIBUTES.getKey()
+        + REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+
+    @Before
+    public void setup() throws Exception {
+        super.setUp();
+        clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+    }
 
     @Before
     public void setupCreateIndexRequestAndAliasValidator() {
@@ -265,7 +298,7 @@ public void testValidateShrinkIndex() {
         );
 
         assertEquals(
-            "index source must be read-only to resize index. use \"index.blocks.write=true\"",
+            "index source must block write operations to resize index. use \"index.blocks.write=true\"",
             expectThrows(
                 IllegalStateException.class,
                 () -> MetadataCreateIndexService.validateShrinkIndex(
@@ -367,7 +400,7 @@ public void testValidateSplitIndex() {
         );
 
         assertEquals(
-            "index source must be read-only to resize index. use \"index.blocks.write=true\"",
+            "index source must block write operations to resize index. use \"index.blocks.write=true\"",
             expectThrows(
                 IllegalStateException.class,
                 () -> MetadataCreateIndexService.validateSplitIndex(
@@ -426,6 +459,65 @@ public void testValidateSplitIndex() {
         );
     }
 
+    public void testValidateCloneIndex() {
+        int numShards = randomIntBetween(1, 42);
+        Settings targetSettings = Settings.builder().put("index.number_of_shards", numShards).build();
+        ClusterState state = createClusterState(
+            "source",
+            numShards,
+            randomIntBetween(0, 10),
+            Settings.builder().put("index.blocks.write", true).build()
+        );
+
+        assertEquals(
+            "index [source] already exists",
+            expectThrows(
+                ResourceAlreadyExistsException.class,
+                () -> MetadataCreateIndexService.validateCloneIndex(state, "target", "source", targetSettings)
+            ).getMessage()
+        );
+
+        assertEquals(
+            "no such index [no_such_index]",
+            expectThrows(
+                IndexNotFoundException.class,
+                () -> MetadataCreateIndexService.validateCloneIndex(state, "no_such_index", "target", targetSettings)
+            ).getMessage()
+        );
+
+        assertEquals(
+            "index source must block write operations to resize index. use \"index.blocks.write=true\"",
+            expectThrows(
+                IllegalStateException.class,
+                () -> MetadataCreateIndexService.validateCloneIndex(
+                    createClusterState("source", randomIntBetween(2, 100), randomIntBetween(0, 10), Settings.EMPTY),
+                    "source",
+                    "target",
+                    targetSettings
+                )
+            ).getMessage()
+        );
+
+        ClusterState clusterState = ClusterState.builder(
+            createClusterState("source", numShards, 0, Settings.builder().put("index.blocks.write", true).build())
+        ).nodes(DiscoveryNodes.builder().add(newNode("node1"))).build();
+        AllocationService service = new AllocationService(
+            new AllocationDeciders(singleton(new MaxRetryAllocationDecider())),
+            new TestGatewayAllocator(),
+            new BalancedShardsAllocator(Settings.EMPTY),
+            EmptyClusterInfoService.INSTANCE,
+            EmptySnapshotsInfoService.INSTANCE
+        );
+
+        RoutingTable routingTable = service.reroute(clusterState, "reroute").routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+        // now we start the shard
+        routingTable = OpenSearchAllocationTestCase.startInitializingShardsAndReroute(service, clusterState, "source").routingTable();
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
+
+        MetadataCreateIndexService.validateCloneIndex(clusterState, "source", "target", targetSettings);
+    }
+
     public void testPrepareResizeIndexSettings() {
         final List<Version> versions = Arrays.asList(VersionUtils.randomVersion(random()), VersionUtils.randomVersion(random()));
         versions.sort(Comparator.comparingLong(l -> l.id));
@@ -595,15 +687,20 @@ public void testValidateIndexName() throws Exception {
                 null,
                 null,
                 null,
-                createTestShardLimitService(randomIntBetween(1, 1000), clusterService),
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
                 null,
                 null,
                 threadPool,
                 null,
                 new SystemIndices(Collections.emptyMap()),
-                false
+                false,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
+            );
+            validateIndexName(
+                checkerService,
+                "index?name",
+                "must not contain the following characters " + org.opensearch.core.common.Strings.INVALID_FILENAME_CHARS
             );
-            validateIndexName(checkerService, "index?name", "must not contain the following characters " + Strings.INVALID_FILENAME_CHARS);
 
             validateIndexName(checkerService, "index#name", "must not contain '#'");
 
@@ -676,13 +773,14 @@ public void testValidateDotIndex() {
                 null,
                 null,
                 null,
-                createTestShardLimitService(randomIntBetween(1, 1000), clusterService),
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
                 null,
                 null,
                 threadPool,
                 null,
                 new SystemIndices(Collections.singletonMap("foo", systemIndexDescriptors)),
-                false
+                false,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
             );
             // Check deprecations
             assertFalse(checkerService.validateDotIndex(".test2", false));
@@ -727,12 +825,12 @@ public void testParseMappingsAppliesDataFromTemplateAndRequest() throws Exceptio
     }
 
     public void testAggregateSettingsAppliesSettingsFromTemplatesAndRequest() {
-        IndexTemplateMetadata templateMetadata = addMatchingTemplate(
-            builder -> { builder.settings(Settings.builder().put("template_setting", "value1")); }
-        );
-        ImmutableOpenMap.Builder<String, IndexTemplateMetadata> templatesBuilder = ImmutableOpenMap.builder();
+        IndexTemplateMetadata templateMetadata = addMatchingTemplate(builder -> {
+            builder.settings(Settings.builder().put("template_setting", "value1"));
+        });
+        final Map<String, IndexTemplateMetadata> templatesBuilder = new HashMap<>();
         templatesBuilder.put("template_1", templateMetadata);
-        Metadata metadata = new Metadata.Builder().templates(templatesBuilder.build()).build();
+        Metadata metadata = new Metadata.Builder().templates(templatesBuilder).build();
         ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
             .metadata(metadata)
             .build();
@@ -746,7 +844,8 @@ public void testAggregateSettingsAppliesSettingsFromTemplatesAndRequest() {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
 
         assertThat(aggregatedIndexSettings.get("template_setting"), equalTo("value1"));
@@ -808,7 +907,8 @@ public void testRequestDataHavePriorityOverTemplateData() throws Exception {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
 
         assertThat(resolvedAliases.get(0).getSearchRouting(), equalTo("fromRequest"));
@@ -830,7 +930,8 @@ public void testDefaultSettings() {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
 
         assertThat(aggregatedIndexSettings.get(SETTING_NUMBER_OF_SHARDS), equalTo("1"));
@@ -845,7 +946,8 @@ public void testSettingsFromClusterState() {
             Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 15).build(),
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
 
         assertThat(aggregatedIndexSettings.get(SETTING_NUMBER_OF_SHARDS), equalTo("15"));
@@ -882,7 +984,8 @@ public void testTemplateOrder() throws Exception {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
         List<AliasMetadata> resolvedAliases = resolveAndValidateAliases(
             request.index(),
@@ -921,7 +1024,8 @@ public void testAggregateIndexSettingsIgnoresTemplatesOnCreateFromSourceIndex()
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
 
         assertThat(aggregatedIndexSettings.get("templateSetting"), is(nullValue()));
@@ -949,13 +1053,7 @@ public void testClusterStateCreateIndexThrowsWriteIndexValidationException() thr
         assertThat(
             expectThrows(
                 IllegalStateException.class,
-                () -> clusterStateCreateIndex(
-                    currentClusterState,
-                    org.opensearch.common.collect.Set.of(),
-                    newIndex,
-                    (state, reason) -> state,
-                    null
-                )
+                () -> clusterStateCreateIndex(currentClusterState, Set.of(), newIndex, (state, reason) -> state, null)
             ).getMessage(),
             startsWith("alias [alias1] has more than one write index [")
         );
@@ -980,7 +1078,7 @@ public void testClusterStateCreateIndex() {
 
         ClusterState updatedClusterState = clusterStateCreateIndex(
             currentClusterState,
-            org.opensearch.common.collect.Set.of(INDEX_READ_ONLY_BLOCK),
+            Set.of(INDEX_READ_ONLY_BLOCK),
             newIndexMetadata,
             rerouteRoutingTable,
             null
@@ -1012,14 +1110,14 @@ public void testClusterStateCreateIndexWithMetadataTransaction() {
 
         // adds alias from new index to existing index
         BiConsumer<Metadata.Builder, IndexMetadata> metadataTransformer = (builder, indexMetadata) -> {
-            AliasMetadata newAlias = indexMetadata.getAliases().iterator().next().value;
+            AliasMetadata newAlias = indexMetadata.getAliases().values().iterator().next();
             IndexMetadata myIndex = builder.get("my-index");
             builder.put(IndexMetadata.builder(myIndex).putAlias(AliasMetadata.builder(newAlias.getAlias()).build()));
         };
 
         ClusterState updatedClusterState = clusterStateCreateIndex(
             currentClusterState,
-            org.opensearch.common.collect.Set.of(INDEX_READ_ONLY_BLOCK),
+            Set.of(INDEX_READ_ONLY_BLOCK),
             newIndexMetadata,
             (clusterState, y) -> clusterState,
             metadataTransformer
@@ -1073,6 +1171,264 @@ public void testParseMappingsWithTypelessTemplate() throws Exception {
         assertThat(mappings, Matchers.hasKey(MapperService.SINGLE_MAPPING_NAME));
     }
 
+    public void testvalidateIndexSettings() {
+        ClusterService clusterService = mock(ClusterService.class);
+        Metadata metadata = Metadata.builder()
+            .transientSettings(Settings.builder().put(Metadata.DEFAULT_REPLICA_COUNT_SETTING.getKey(), 1).build())
+            .build();
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .build();
+
+        ThreadPool threadPool = new TestThreadPool(getTestName());
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .build();
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        when(clusterService.getSettings()).thenReturn(settings);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        when(clusterService.state()).thenReturn(clusterState);
+
+        MetadataCreateIndexService checkerService = new MetadataCreateIndexService(
+            settings,
+            clusterService,
+            null,
+            null,
+            null,
+            createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
+            new Environment(Settings.builder().put("path.home", "dummy").build(), null),
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            threadPool,
+            null,
+            new SystemIndices(Collections.emptyMap()),
+            true,
+            new AwarenessReplicaBalance(settings, clusterService.getClusterSettings())
+        );
+
+        List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(settings, false, Optional.empty());
+        assertThat(validationErrors.size(), is(1));
+        assertThat(validationErrors.get(0), is("expected total copies needs to be a multiple of total awareness attributes [3]"));
+
+        settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .put(SETTING_NUMBER_OF_REPLICAS, 2)
+            .build();
+
+        validationErrors = checkerService.getIndexSettingsValidationErrors(settings, false, Optional.empty());
+        assertThat(validationErrors.size(), is(0));
+
+        threadPool.shutdown();
+    }
+
+    public void testRemoteStoreNoUserOverrideExceptReplicationTypeSegmentIndexSettings() {
+        Settings settings = Settings.builder()
+            .put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.DOCUMENT)
+            .put(segmentRepositoryNameAttributeKey, "my-segment-repo-1")
+            .put(translogRepositoryNameAttributeKey, "my-translog-repo-1")
+            .build();
+
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+        request.settings(requestSettings.build());
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        verifyRemoteStoreIndexSettings(
+            indexSettings,
+            "true",
+            "my-segment-repo-1",
+            "my-translog-repo-1",
+            ReplicationType.SEGMENT.toString(),
+            IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
+        );
+    }
+
+    public void testRemoteStoreImplicitOverrideReplicationTypeToSegmentForRemoteStore() {
+        Settings settings = Settings.builder()
+            .put(segmentRepositoryNameAttributeKey, "my-segment-repo-1")
+            .put(translogRepositoryNameAttributeKey, "my-translog-repo-1")
+            .build();
+
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        request.settings(requestSettings.build());
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        verifyRemoteStoreIndexSettings(
+            indexSettings,
+            "true",
+            "my-segment-repo-1",
+            "my-translog-repo-1",
+            ReplicationType.SEGMENT.toString(),
+            IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
+        );
+    }
+
+    public void testRemoteStoreNoUserOverrideIndexSettings() {
+        Settings settings = Settings.builder()
+            .put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT)
+            .put(segmentRepositoryNameAttributeKey, "my-segment-repo-1")
+            .put(translogRepositoryNameAttributeKey, "my-translog-repo-1")
+            .build();
+
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        verifyRemoteStoreIndexSettings(
+            indexSettings,
+            "true",
+            "my-segment-repo-1",
+            "my-translog-repo-1",
+            ReplicationType.SEGMENT.toString(),
+            IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
+        );
+    }
+
+    public void testRemoteStoreDisabledByUserIndexSettings() {
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(SETTING_REMOTE_STORE_ENABLED, false);
+        withTemporaryClusterService(((clusterService, threadPool) -> {
+            MetadataCreateIndexService checkerService = new MetadataCreateIndexService(
+                Settings.EMPTY,
+                clusterService,
+                null,
+                null,
+                null,
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
+                new Environment(Settings.builder().put("path.home", "dummy").build(), null),
+                IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+                threadPool,
+                null,
+                new SystemIndices(Collections.emptyMap()),
+                true,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
+            );
+
+            final List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(
+                requestSettings.build(),
+                true,
+                Optional.empty()
+            );
+            assertThat(validationErrors.size(), is(1));
+            assertThat(
+                validationErrors.get(0),
+                is(String.format(Locale.ROOT, "private index setting [%s] can not be set explicitly", SETTING_REMOTE_STORE_ENABLED))
+            );
+        }));
+    }
+
+    public void testRemoteStoreOverrideSegmentRepoIndexSettings() {
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-custom-repo");
+        withTemporaryClusterService(((clusterService, threadPool) -> {
+            MetadataCreateIndexService checkerService = new MetadataCreateIndexService(
+                Settings.EMPTY,
+                clusterService,
+                null,
+                null,
+                null,
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
+                new Environment(Settings.builder().put("path.home", "dummy").build(), null),
+                IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+                threadPool,
+                null,
+                new SystemIndices(Collections.emptyMap()),
+                true,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
+            );
+
+            final List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(
+                requestSettings.build(),
+                true,
+                Optional.empty()
+            );
+            assertThat(validationErrors.size(), is(1));
+            assertThat(
+                validationErrors.get(0),
+                is(
+                    String.format(
+                        Locale.ROOT,
+                        "private index setting [%s] can not be set explicitly",
+                        SETTING_REMOTE_SEGMENT_STORE_REPOSITORY
+                    )
+                )
+            );
+        }));
+    }
+
+    public void testRemoteStoreOverrideTranslogRepoIndexSettings() {
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "my-custom-repo");
+        withTemporaryClusterService(((clusterService, threadPool) -> {
+            MetadataCreateIndexService checkerService = new MetadataCreateIndexService(
+                Settings.EMPTY,
+                clusterService,
+                null,
+                null,
+                null,
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
+                new Environment(Settings.builder().put("path.home", "dummy").build(), null),
+                IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+                threadPool,
+                null,
+                new SystemIndices(Collections.emptyMap()),
+                true,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
+            );
+
+            final List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(
+                requestSettings.build(),
+                true,
+                Optional.empty()
+            );
+            assertThat(validationErrors.size(), is(1));
+            assertThat(
+                validationErrors.get(0),
+                is(
+                    String.format(
+                        Locale.ROOT,
+                        "private index setting [%s] can not be set explicitly",
+                        SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY
+                    )
+                )
+            );
+        }));
+    }
+
     public void testBuildIndexMetadata() {
         IndexMetadata sourceIndexMetadata = IndexMetadata.builder("parent")
             .settings(Settings.builder().put("index.version.created", Version.CURRENT).build())
@@ -1090,7 +1446,7 @@ public void testBuildIndexMetadata() {
         IndexMetadata indexMetadata = buildIndexMetadata("test", aliases, () -> null, indexSettings, 4, sourceIndexMetadata, false);
 
         assertThat(indexMetadata.getAliases().size(), is(1));
-        assertThat(indexMetadata.getAliases().keys().iterator().next().value, is("alias1"));
+        assertThat(indexMetadata.getAliases().keySet().iterator().next(), is("alias1"));
         assertThat("The source index primary term must be used", indexMetadata.primaryTerm(0), is(3L));
     }
 
@@ -1142,7 +1498,8 @@ public void testSoftDeletesDisabledIsRejected() {
                 Settings.EMPTY,
                 IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
                 randomShardLimitService(),
-                Collections.emptySet()
+                Collections.emptySet(),
+                clusterSettings
             );
         });
         assertThat(
@@ -1171,7 +1528,8 @@ public void testValidateTranslogRetentionSettings() {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
         assertWarnings(
             "Translog retention settings [index.translog.retention.age] "
@@ -1189,16 +1547,17 @@ public void testIndexLifecycleNameSetting() {
                 null,
                 null,
                 null,
-                createTestShardLimitService(randomIntBetween(1, 1000), clusterService),
+                createTestShardLimitService(randomIntBetween(1, 1000), false, clusterService),
                 new Environment(Settings.builder().put("path.home", "dummy").build(), null),
                 new IndexScopedSettings(ilnSetting, Collections.emptySet()),
                 threadPool,
                 null,
                 new SystemIndices(Collections.emptyMap()),
-                true
+                true,
+                new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
             );
 
-            final List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(ilnSetting, true);
+            final List<String> validationErrors = checkerService.getIndexSettingsValidationErrors(ilnSetting, true, Optional.empty());
             assertThat(validationErrors.size(), is(1));
             assertThat(validationErrors.get(0), is("expected [index.lifecycle.name] to be private but it was not"));
         }));
@@ -1217,7 +1576,8 @@ public void testDeprecatedSimpleFSStoreSettings() {
             Settings.EMPTY,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             randomShardLimitService(),
-            Collections.emptySet()
+            Collections.emptySet(),
+            clusterSettings
         );
         assertWarnings(
             "[simplefs] is deprecated and will be removed in 2.0. Use [niofs], which offers equal "
@@ -1225,6 +1585,240 @@ public void testDeprecatedSimpleFSStoreSettings() {
         );
     }
 
+    public void testClusterReplicationSetting() {
+        Settings settings = Settings.builder().put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT).build();
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        assertEquals(ReplicationType.SEGMENT.toString(), indexSettings.get(SETTING_REPLICATION_TYPE));
+    }
+
+    public void testIndexSettingOverridesClusterReplicationSetting() {
+        Settings settings = Settings.builder().put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT).build();
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        // Set index setting replication type as DOCUMENT
+        requestSettings.put(SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT);
+        request.settings(requestSettings.build());
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        // Verify if index setting overrides cluster replication setting
+        assertEquals(ReplicationType.DOCUMENT.toString(), indexSettings.get(SETTING_REPLICATION_TYPE));
+    }
+
+    public void testRefreshIntervalValidationWithNoIndexSetting() {
+        // This checks that aggregateIndexSetting works for the case where there are no index setting
+        // `index.refresh_interval` in the cluster state update request.
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            Settings.EMPTY,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+    }
+
+    public void testRefreshIntervalValidationSuccessWithIndexSettingEqualToClusterMinimum() {
+        // This checks that aggregateIndexSettings works for the case when the index setting `index.refresh_interval`
+        // is set to a value that is equal to the `cluster.default.index.refresh_interval` value.
+        TimeValue refreshInterval = TimeValue.timeValueSeconds(10);
+        Settings settings = Settings.builder()
+            .put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), refreshInterval)
+            .put(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), refreshInterval)
+            .build();
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        // Set index setting refresh interval the same value as the cluster minimum refresh interval
+        requestSettings.put(INDEX_REFRESH_INTERVAL_SETTING.getKey(), refreshInterval);
+        request.settings(requestSettings.build());
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        // Verify that the value is the same as set as earlier and the validation was successful
+        assertEquals(refreshInterval, INDEX_REFRESH_INTERVAL_SETTING.get(indexSettings));
+    }
+
+    public void testRefreshIntervalValidationSuccessWithIndexSettingGreaterThanClusterMinimum() {
+        // This checks that aggregateIndexSettings works for the case when the index setting `index.refresh_interval`
+        // is set to a value that is greater than the `cluster.default.index.refresh_interval` value.
+        int clusterMinRefreshTimeMs = 10 * 1000;
+        TimeValue clusterMinRefreshTime = TimeValue.timeValueSeconds(clusterMinRefreshTimeMs);
+        Settings settings = Settings.builder()
+            .put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterMinRefreshTime)
+            .put(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterMinRefreshTime)
+            .build();
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        // Set index setting refresh interval the same value as the cluster minimum refresh interval
+        TimeValue indexRefreshTime = TimeValue.timeValueMillis(clusterMinRefreshTimeMs + randomNonNegativeLong());
+        requestSettings.put(INDEX_REFRESH_INTERVAL_SETTING.getKey(), indexRefreshTime);
+        request.settings(requestSettings.build());
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            settings,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        // Verify that the value is the same as set as earlier and the validation was successful
+        assertEquals(indexRefreshTime, INDEX_REFRESH_INTERVAL_SETTING.get(indexSettings));
+    }
+
+    public void testRefreshIntervalValidationFailureWithIndexSetting() {
+        // This checks that aggregateIndexSettings works for the case when the index setting `index.refresh_interval`
+        // is set to a value that is below the `cluster.default.index.refresh_interval` value.
+        int clusterMinRefreshTimeMs = 10 * 1000;
+        TimeValue clusterMinRefreshTime = TimeValue.timeValueMillis(clusterMinRefreshTimeMs);
+        Settings settings = Settings.builder()
+            .put(CLUSTER_MINIMUM_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterMinRefreshTime)
+            .put(CLUSTER_DEFAULT_INDEX_REFRESH_INTERVAL_SETTING.getKey(), clusterMinRefreshTime)
+            .build();
+        clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        // Set index setting refresh interval the same value as the cluster minimum refresh interval
+        TimeValue indexRefreshTime = TimeValue.timeValueMillis(clusterMinRefreshTimeMs - randomIntBetween(1, clusterMinRefreshTimeMs - 1));
+        requestSettings.put(INDEX_REFRESH_INTERVAL_SETTING.getKey(), indexRefreshTime);
+        request.settings(requestSettings.build());
+        IllegalArgumentException exception = assertThrows(
+            IllegalArgumentException.class,
+            () -> aggregateIndexSettings(
+                ClusterState.EMPTY_STATE,
+                request,
+                Settings.EMPTY,
+                null,
+                Settings.EMPTY,
+                IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+                randomShardLimitService(),
+                Collections.emptySet(),
+                clusterSettings
+            )
+        );
+        // verify that the message is as expected
+        assertEquals(
+            "invalid index.refresh_interval ["
+                + indexRefreshTime
+                + "]: cannot be smaller than cluster.minimum.index.refresh_interval [10s]",
+            exception.getMessage()
+        );
+    }
+
+    public void testAnyTranslogDurabilityWhenRestrictSettingFalse() {
+        // This checks that aggregateIndexSettings works for the case when the cluster setting
+        // cluster.remote_store.index.restrict.async-durability is false or not set, it allows all types of durability modes
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        Translog.Durability durability = randomFrom(Translog.Durability.values());
+        requestSettings.put(INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), durability);
+        request.settings(requestSettings.build());
+        if (randomBoolean()) {
+            Settings settings = Settings.builder().put(CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey(), false).build();
+            clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        }
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            Settings.EMPTY,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        assertFalse(clusterSettings.get(IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING));
+        assertEquals(durability, INDEX_TRANSLOG_DURABILITY_SETTING.get(indexSettings));
+    }
+
+    public void testAsyncDurabilityThrowsExceptionWhenRestrictSettingTrue() {
+        // This checks that aggregateIndexSettings works for the case when the cluster setting
+        // cluster.remote_store.index.restrict.async-durability is false or not set, it allows all types of durability modes
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Translog.Durability.ASYNC);
+        request.settings(requestSettings.build());
+        Settings settings = Settings.builder().put(CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey(), true).build();
+        clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        IllegalArgumentException exception = assertThrows(
+            IllegalArgumentException.class,
+            () -> aggregateIndexSettings(
+                ClusterState.EMPTY_STATE,
+                request,
+                Settings.EMPTY,
+                null,
+                Settings.builder().put("node.attr.remote_store.setting", "test").build(),
+                IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+                randomShardLimitService(),
+                Collections.emptySet(),
+                clusterSettings
+            )
+        );
+        // verify that the message is as expected
+        assertEquals(
+            "index setting [index.translog.durability=async] is not allowed as cluster setting [cluster.remote_store.index.restrict.async-durability=true]",
+            exception.getMessage()
+        );
+    }
+
+    public void testRequestDurabilityWhenRestrictSettingTrue() {
+        // This checks that aggregateIndexSettings works for the case when the cluster setting
+        // cluster.remote_store.index.restrict.async-durability is false or not set, it allows all types of durability modes
+        request = new CreateIndexClusterStateUpdateRequest("create index", "test", "test");
+        final Settings.Builder requestSettings = Settings.builder();
+        requestSettings.put(INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Translog.Durability.REQUEST);
+        request.settings(requestSettings.build());
+        Settings settings = Settings.builder().put(CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING.getKey(), true).build();
+        clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        Settings indexSettings = aggregateIndexSettings(
+            ClusterState.EMPTY_STATE,
+            request,
+            Settings.EMPTY,
+            null,
+            Settings.EMPTY,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Collections.emptySet(),
+            clusterSettings
+        );
+        assertTrue(clusterSettings.get(IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING));
+        assertEquals(Translog.Durability.REQUEST, INDEX_TRANSLOG_DURABILITY_SETTING.get(indexSettings));
+    }
+
     private IndexTemplateMetadata addMatchingTemplate(Consumer<IndexTemplateMetadata.Builder> configurator) {
         IndexTemplateMetadata.Builder builder = templateMetadataBuilder("template1", "te*");
         configurator.accept(builder);
@@ -1237,18 +1831,17 @@ private IndexTemplateMetadata.Builder templateMetadataBuilder(String name, Strin
 
     private CompressedXContent createMapping(String fieldName, String fieldType) {
         try {
-            final String mapping = Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject(MapperService.SINGLE_MAPPING_NAME)
-                    .startObject("properties")
-                    .startObject(fieldName)
-                    .field("type", fieldType)
-                    .endObject()
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+            final String mapping = XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject(MapperService.SINGLE_MAPPING_NAME)
+                .startObject("properties")
+                .startObject(fieldName)
+                .field("type", fieldType)
+                .endObject()
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
 
             return new CompressedXContent(mapping);
         } catch (IOException e) {
@@ -1256,16 +1849,8 @@ private CompressedXContent createMapping(String fieldName, String fieldType) {
         }
     }
 
-    private static Map<String, CompressedXContent> convertMappings(ImmutableOpenMap<String, CompressedXContent> mappings) {
-        Map<String, CompressedXContent> converted = new HashMap<>(mappings.size());
-        for (ObjectObjectCursor<String, CompressedXContent> cursor : mappings) {
-            converted.put(cursor.key, cursor.value);
-        }
-        return converted;
-    }
-
     private ShardLimitValidator randomShardLimitService() {
-        return createTestShardLimitService(randomIntBetween(10, 10000));
+        return createTestShardLimitService(randomIntBetween(10, 10000), false);
     }
 
     private void withTemporaryClusterService(BiConsumer<ClusterService, ThreadPool> consumer) {
@@ -1277,4 +1862,25 @@ private void withTemporaryClusterService(BiConsumer<ClusterService, ThreadPool>
             threadPool.shutdown();
         }
     }
+
+    private void verifyRemoteStoreIndexSettings(
+        Settings indexSettings,
+        String isRemoteSegmentEnabled,
+        String remoteSegmentRepo,
+        String remoteTranslogRepo,
+        String replicationType,
+        TimeValue translogBufferInterval
+    ) {
+        assertEquals(replicationType, indexSettings.get(SETTING_REPLICATION_TYPE));
+        assertEquals(isRemoteSegmentEnabled, indexSettings.get(SETTING_REMOTE_STORE_ENABLED));
+        assertEquals(remoteSegmentRepo, indexSettings.get(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY));
+        assertEquals(remoteTranslogRepo, indexSettings.get(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY));
+        assertEquals(translogBufferInterval, INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(indexSettings));
+    }
+
+    @After
+    public void shutdown() throws Exception {
+        clusterSettings = null;
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataDeleteIndexServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataDeleteIndexServiceTests.java
index c374392fc3d0e..ccce338e388ae 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataDeleteIndexServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataDeleteIndexServiceTests.java
@@ -39,10 +39,10 @@
 import org.opensearch.cluster.block.ClusterBlocks;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
-import org.opensearch.common.collect.ImmutableOpenMap;
+import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
@@ -54,10 +54,11 @@
 import org.hamcrest.core.IsNull;
 import org.junit.Before;
 
-import java.util.HashSet;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
@@ -83,7 +84,7 @@ public void setUp() throws Exception {
         when(allocationService.reroute(any(ClusterState.class), any(String.class))).thenAnswer(
             mockInvocation -> mockInvocation.getArguments()[0]
         );
-        service = new MetadataDeleteIndexService(Settings.EMPTY, null, allocationService);
+        service = new MetadataDeleteIndexService(Settings.EMPTY, mock(ClusterService.class), allocationService);
     }
 
     public void testDeleteMissing() {
@@ -97,7 +98,7 @@ public void testDeleteSnapshotting() {
         String index = randomAlphaOfLength(5);
         Snapshot snapshot = new Snapshot("doesn't matter", new SnapshotId("snapshot name", "snapshot uuid"));
         SnapshotsInProgress snaps = SnapshotsInProgress.of(
-            org.opensearch.common.collect.List.of(
+            List.of(
                 new SnapshotsInProgress.Entry(
                     snapshot,
                     true,
@@ -107,10 +108,11 @@ public void testDeleteSnapshotting() {
                     Collections.emptyList(),
                     System.currentTimeMillis(),
                     (long) randomIntBetween(0, 1000),
-                    ImmutableOpenMap.of(),
+                    Map.of(),
                     null,
                     SnapshotInfoTests.randomUserMetadata(),
-                    VersionUtils.randomVersion(random())
+                    VersionUtils.randomVersion(random()),
+                    false
                 )
             )
         );
@@ -152,14 +154,14 @@ public void testDeleteBackingIndexForDataStream() {
         int numBackingIndices = randomIntBetween(2, 5);
         String dataStreamName = randomAlphaOfLength(6).toLowerCase(Locale.ROOT);
         ClusterState before = DataStreamTestHelper.getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamName, numBackingIndices)),
-            org.opensearch.common.collect.List.of()
+            List.of(new Tuple<>(dataStreamName, numBackingIndices)),
+            List.of()
         );
 
         int numIndexToDelete = randomIntBetween(1, numBackingIndices - 1);
 
         Index indexToDelete = before.metadata().index(DataStream.getDefaultBackingIndexName(dataStreamName, numIndexToDelete)).getIndex();
-        ClusterState after = service.deleteIndices(before, org.opensearch.common.collect.Set.of(indexToDelete));
+        ClusterState after = service.deleteIndices(before, Set.of(indexToDelete));
 
         assertThat(after.metadata().getIndices().get(indexToDelete.getName()), IsNull.nullValue());
         assertThat(after.metadata().getIndices().size(), equalTo(numBackingIndices - 1));
@@ -174,8 +176,8 @@ public void testDeleteMultipleBackingIndexForDataStream() {
         int numBackingIndicesToDelete = randomIntBetween(2, numBackingIndices - 1);
         String dataStreamName = randomAlphaOfLength(6).toLowerCase(Locale.ROOT);
         ClusterState before = DataStreamTestHelper.getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamName, numBackingIndices)),
-            org.opensearch.common.collect.List.of()
+            List.of(new Tuple<>(dataStreamName, numBackingIndices)),
+            List.of()
         );
 
         List<Integer> indexNumbersToDelete = randomSubsetOf(
@@ -203,15 +205,12 @@ public void testDeleteCurrentWriteIndexForDataStream() {
         int numBackingIndices = randomIntBetween(1, 5);
         String dataStreamName = randomAlphaOfLength(6).toLowerCase(Locale.ROOT);
         ClusterState before = DataStreamTestHelper.getClusterStateWithDataStreams(
-            org.opensearch.common.collect.List.of(new Tuple<>(dataStreamName, numBackingIndices)),
-            org.opensearch.common.collect.List.of()
+            List.of(new Tuple<>(dataStreamName, numBackingIndices)),
+            List.of()
         );
 
         Index indexToDelete = before.metadata().index(DataStream.getDefaultBackingIndexName(dataStreamName, numBackingIndices)).getIndex();
-        Exception e = expectThrows(
-            IllegalArgumentException.class,
-            () -> service.deleteIndices(before, org.opensearch.common.collect.Set.of(indexToDelete))
-        );
+        Exception e = expectThrows(IllegalArgumentException.class, () -> service.deleteIndices(before, Set.of(indexToDelete)));
 
         assertThat(
             e.getMessage(),
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexAliasesServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexAliasesServiceTests.java
index d37756dabfe8d..bf66f577e182b 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexAliasesServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexAliasesServiceTests.java
@@ -35,9 +35,10 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
@@ -66,7 +67,7 @@ public class MetadataIndexAliasesServiceTests extends OpenSearchTestCase {
     private final AliasValidator aliasValidator = new AliasValidator();
     private final MetadataDeleteIndexService deleteIndexService = mock(MetadataDeleteIndexService.class);
     private final MetadataIndexAliasesService service = new MetadataIndexAliasesService(
-        null,
+        mock(ClusterService.class),
         null,
         aliasValidator,
         deleteIndexService,
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceTests.java
index fb01a493ff7c3..9181d8f6301d9 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceTests.java
@@ -55,13 +55,12 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
@@ -450,10 +449,7 @@ public void testCloseCurrentWriteIndexForDataStream() {
             dataStreamsToCreate.add(new Tuple<>(dataStreamName, numBackingIndices));
             writeIndices.add(DataStream.getDefaultBackingIndexName(dataStreamName, numBackingIndices));
         }
-        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(
-            dataStreamsToCreate,
-            org.opensearch.common.collect.List.of()
-        );
+        ClusterState cs = DeleteDataStreamRequestTests.getClusterStateWithDataStreams(dataStreamsToCreate, List.of());
 
         ClusterService clusterService = mock(ClusterService.class);
         when(clusterService.state()).thenReturn(cs);
@@ -496,7 +492,7 @@ private static ClusterState addBlockedIndex(
     private static ClusterState addRestoredIndex(final String index, final int numShards, final int numReplicas, final ClusterState state) {
         ClusterState newState = addOpenedIndex(index, numShards, numReplicas, state);
 
-        final ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shardsBuilder = ImmutableOpenMap.builder();
+        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shardsBuilder = new HashMap<>();
         for (ShardRouting shardRouting : newState.routingTable().index(index).randomAllActiveShardsIt()) {
             shardsBuilder.put(shardRouting.shardId(), new RestoreInProgress.ShardRestoreStatus(shardRouting.currentNodeId()));
         }
@@ -507,7 +503,7 @@ private static ClusterState addRestoredIndex(final String index, final int numSh
             snapshot,
             RestoreInProgress.State.INIT,
             Collections.singletonList(index),
-            shardsBuilder.build()
+            shardsBuilder
         );
         return ClusterState.builder(newState).putCustom(RestoreInProgress.TYPE, new RestoreInProgress.Builder().add(entry).build()).build();
     }
@@ -515,7 +511,7 @@ private static ClusterState addRestoredIndex(final String index, final int numSh
     private static ClusterState addSnapshotIndex(final String index, final int numShards, final int numReplicas, final ClusterState state) {
         ClusterState newState = addOpenedIndex(index, numShards, numReplicas, state);
 
-        final ImmutableOpenMap.Builder<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardsBuilder = ImmutableOpenMap.builder();
+        final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardsBuilder = new HashMap<>();
         for (ShardRouting shardRouting : newState.routingTable().index(index).randomAllActiveShardsIt()) {
             shardsBuilder.put(shardRouting.shardId(), new SnapshotsInProgress.ShardSnapshotStatus(shardRouting.currentNodeId(), "1"));
         }
@@ -530,10 +526,11 @@ private static ClusterState addSnapshotIndex(final String index, final int numSh
             Collections.emptyList(),
             randomNonNegativeLong(),
             randomLong(),
-            shardsBuilder.build(),
+            shardsBuilder,
             null,
             SnapshotInfoTests.randomUserMetadata(),
-            VersionUtils.randomVersion(random())
+            VersionUtils.randomVersion(random()),
+            false
         );
         return ClusterState.builder(newState)
             .putCustom(SnapshotsInProgress.TYPE, SnapshotsInProgress.of(Collections.singletonList(entry)))
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceUtils.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceUtils.java
index 3f16813dedbb7..6947b6432ccc1 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceUtils.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexStateServiceUtils.java
@@ -34,7 +34,7 @@
 import org.opensearch.action.admin.indices.close.CloseIndexResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlock;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 
 import java.util.Map;
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexTemplateServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexTemplateServiceTests.java
index c3a16a1e25bc8..41e9a109cbe11 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexTemplateServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexTemplateServiceTests.java
@@ -33,28 +33,28 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.MetadataIndexTemplateService.PutRequest;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.IndexTemplateMissingException;
-import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.InvalidIndexTemplateException;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -75,6 +75,10 @@
 import java.util.stream.Collectors;
 
 import static java.util.Collections.singletonList;
+import static org.opensearch.common.settings.Settings.builder;
+import static org.opensearch.env.Environment.PATH_HOME_SETTING;
+import static org.opensearch.index.mapper.DataStreamFieldMapper.Defaults.TIMESTAMP_FIELD;
+import static org.opensearch.indices.ShardLimitValidatorTests.createTestShardLimitService;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.containsStringIgnoringCase;
 import static org.hamcrest.CoreMatchers.equalTo;
@@ -85,9 +89,8 @@
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.matchesRegex;
-import static org.opensearch.common.settings.Settings.builder;
-import static org.opensearch.index.mapper.DataStreamFieldMapper.Defaults.TIMESTAMP_FIELD;
-import static org.opensearch.indices.ShardLimitValidatorTests.createTestShardLimitService;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class MetadataIndexTemplateServiceTests extends OpenSearchSingleNodeTestCase {
 
@@ -186,17 +189,16 @@ public void testIndexTemplateWithValidateMapping() throws Exception {
         PutRequest request = new PutRequest("api", "validate_template");
         request.patterns(singletonList("te*"));
         request.mappings(
-            Strings.toString(
-                XContentFactory.jsonBuilder()
-                    .startObject()
-                    .startObject("properties")
-                    .startObject("field2")
-                    .field("type", "text")
-                    .field("analyzer", "custom_1")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            )
+            XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("properties")
+                .startObject("field2")
+                .field("type", "text")
+                .field("analyzer", "custom_1")
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString()
         );
 
         List<Throwable> errors = putTemplateDetail(request);
@@ -425,9 +427,9 @@ public void testUpdateComponentTemplateWithIndexHiddenSetting() throws Exception
         assertNotNull(state.metadata().componentTemplates().get("foo"));
 
         ComposableIndexTemplate firstGlobalIndexTemplate = new ComposableIndexTemplate(
-            org.opensearch.common.collect.List.of("*"),
+            List.of("*"),
             template,
-            org.opensearch.common.collect.List.of("foo"),
+            List.of("foo"),
             1L,
             null,
             null,
@@ -436,9 +438,9 @@ public void testUpdateComponentTemplateWithIndexHiddenSetting() throws Exception
         state = metadataIndexTemplateService.addIndexTemplateV2(state, true, "globalindextemplate1", firstGlobalIndexTemplate);
 
         ComposableIndexTemplate secondGlobalIndexTemplate = new ComposableIndexTemplate(
-            org.opensearch.common.collect.List.of("*"),
+            List.of("*"),
             template,
-            org.opensearch.common.collect.List.of("foo"),
+            List.of("foo"),
             2L,
             null,
             null,
@@ -447,9 +449,9 @@ public void testUpdateComponentTemplateWithIndexHiddenSetting() throws Exception
         state = metadataIndexTemplateService.addIndexTemplateV2(state, true, "globalindextemplate2", secondGlobalIndexTemplate);
 
         ComposableIndexTemplate fooPatternIndexTemplate = new ComposableIndexTemplate(
-            org.opensearch.common.collect.List.of("foo-*"),
+            List.of("foo-*"),
             template,
-            org.opensearch.common.collect.List.of("foo"),
+            List.of("foo"),
             3L,
             null,
             null,
@@ -612,9 +614,9 @@ public void onFailure(Exception e) {
         waitToCreateComponentTemplate.await(10, TimeUnit.SECONDS);
 
         ComposableIndexTemplate globalIndexTemplate = new ComposableIndexTemplate(
-            org.opensearch.common.collect.List.of("*"),
+            List.of("*"),
             null,
-            org.opensearch.common.collect.List.of("ct-with-index-hidden-setting"),
+            List.of("ct-with-index-hidden-setting"),
             null,
             null,
             null,
@@ -937,9 +939,9 @@ public void testFindV2InvalidGlobalTemplate() {
         try {
             // add an invalid global template that specifies the `index.hidden` setting
             ComposableIndexTemplate invalidGlobalTemplate = new ComposableIndexTemplate(
-                org.opensearch.common.collect.List.of("*"),
+                List.of("*"),
                 templateWithHiddenSetting,
-                org.opensearch.common.collect.List.of("ct"),
+                List.of("ct"),
                 5L,
                 1L,
                 null,
@@ -948,9 +950,7 @@ public void testFindV2InvalidGlobalTemplate() {
             Metadata invalidGlobalTemplateMetadata = Metadata.builder()
                 .putCustom(
                     ComposableIndexTemplateMetadata.TYPE,
-                    new ComposableIndexTemplateMetadata(
-                        org.opensearch.common.collect.Map.of("invalid_global_template", invalidGlobalTemplate)
-                    )
+                    new ComposableIndexTemplateMetadata(Map.of("invalid_global_template", invalidGlobalTemplate))
                 )
                 .build();
 
@@ -1209,7 +1209,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
 
         {
             ComposableIndexTemplate it = new ComposableIndexTemplate(
-                org.opensearch.common.collect.List.of("logs*"),
+                List.of("logs*"),
                 new Template(
                     null,
                     new CompressedXContent(
@@ -1223,7 +1223,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
                     ),
                     null
                 ),
-                org.opensearch.common.collect.List.of("ct1"),
+                List.of("ct1"),
                 0L,
                 1L,
                 null,
@@ -1241,7 +1241,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
             assertThat(mappings.size(), equalTo(4));
             List<Map<String, Object>> parsedMappings = mappings.stream().map(m -> {
                 try {
-                    return MapperService.parseMapping(new NamedXContentRegistry(org.opensearch.common.collect.List.of()), m.string());
+                    return MapperService.parseMapping(new NamedXContentRegistry(List.of()), m.string());
                 } catch (Exception e) {
                     logger.error(e);
                     fail("failed to parse mappings: " + m.string());
@@ -1249,38 +1249,23 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
                 }
             }).collect(Collectors.toList());
 
-            Map<String, Object> firstParsedMapping = org.opensearch.common.collect.Map.of(
+            Map<String, Object> firstParsedMapping = Map.of(
                 "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of(TIMESTAMP_FIELD.getName(), org.opensearch.common.collect.Map.of("type", "date"))
-                )
+                Map.of("properties", Map.of(TIMESTAMP_FIELD.getName(), Map.of("type", "date")))
             );
             assertThat(parsedMappings.get(0), equalTo(firstParsedMapping));
 
-            Map<String, Object> secondMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field1", org.opensearch.common.collect.Map.of("type", "keyword"))
-                )
-            );
+            Map<String, Object> secondMapping = Map.of("_doc", Map.of("properties", Map.of("field1", Map.of("type", "keyword"))));
             assertThat(parsedMappings.get(1), equalTo(secondMapping));
 
-            Map<String, Object> thirdMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field2", org.opensearch.common.collect.Map.of("type", "integer"))
-                )
-            );
+            Map<String, Object> thirdMapping = Map.of("_doc", Map.of("properties", Map.of("field2", Map.of("type", "integer"))));
             assertThat(parsedMappings.get(2), equalTo(thirdMapping));
         }
 
         {
             // indices matched by templates without the data stream field defined don't get the default @timestamp mapping
             ComposableIndexTemplate it = new ComposableIndexTemplate(
-                org.opensearch.common.collect.List.of("timeseries*"),
+                List.of("timeseries*"),
                 new Template(
                     null,
                     new CompressedXContent(
@@ -1294,7 +1279,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
                     ),
                     null
                 ),
-                org.opensearch.common.collect.List.of("ct1"),
+                List.of("ct1"),
                 0L,
                 1L,
                 null,
@@ -1308,7 +1293,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
             assertThat(mappings.size(), equalTo(2));
             List<Map<String, Object>> parsedMappings = mappings.stream().map(m -> {
                 try {
-                    return MapperService.parseMapping(new NamedXContentRegistry(org.opensearch.common.collect.List.of()), m.string());
+                    return MapperService.parseMapping(new NamedXContentRegistry(List.of()), m.string());
                 } catch (Exception e) {
                     logger.error(e);
                     fail("failed to parse mappings: " + m.string());
@@ -1316,22 +1301,10 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
                 }
             }).collect(Collectors.toList());
 
-            Map<String, Object> firstMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field1", org.opensearch.common.collect.Map.of("type", "keyword"))
-                )
-            );
+            Map<String, Object> firstMapping = Map.of("_doc", Map.of("properties", Map.of("field1", Map.of("type", "keyword"))));
             assertThat(parsedMappings.get(0), equalTo(firstMapping));
 
-            Map<String, Object> secondMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field2", org.opensearch.common.collect.Map.of("type", "integer"))
-                )
-            );
+            Map<String, Object> secondMapping = Map.of("_doc", Map.of("properties", Map.of("field2", Map.of("type", "integer"))));
             assertThat(parsedMappings.get(1), equalTo(secondMapping));
 
             // a default @timestamp mapping will not be added if the matching template doesn't have the data stream field configured, even
@@ -1346,7 +1319,7 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
             assertThat(mappings.size(), equalTo(2));
             parsedMappings = mappings.stream().map(m -> {
                 try {
-                    return MapperService.parseMapping(new NamedXContentRegistry(org.opensearch.common.collect.List.of()), m.string());
+                    return MapperService.parseMapping(new NamedXContentRegistry(List.of()), m.string());
                 } catch (Exception e) {
                     logger.error(e);
                     fail("failed to parse mappings: " + m.string());
@@ -1354,22 +1327,10 @@ public void testDefinedTimestampMappingIsAddedForDataStreamTemplates() throws Ex
                 }
             }).collect(Collectors.toList());
 
-            firstMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field1", org.opensearch.common.collect.Map.of("type", "keyword"))
-                )
-            );
+            firstMapping = Map.of("_doc", Map.of("properties", Map.of("field1", Map.of("type", "keyword"))));
             assertThat(parsedMappings.get(0), equalTo(firstMapping));
 
-            secondMapping = org.opensearch.common.collect.Map.of(
-                "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of("field2", org.opensearch.common.collect.Map.of("type", "integer"))
-                )
-            );
+            secondMapping = Map.of("_doc", Map.of("properties", Map.of("field2", Map.of("type", "integer"))));
             assertThat(parsedMappings.get(1), equalTo(secondMapping));
         }
     }
@@ -1400,9 +1361,9 @@ public void testUserDefinedMappingTakesPrecedenceOverDefault() throws Exception
 
             state = service.addComponentTemplate(state, true, "ct1", ct1);
             ComposableIndexTemplate it = new ComposableIndexTemplate(
-                org.opensearch.common.collect.List.of("logs*"),
+                List.of("logs*"),
                 null,
-                org.opensearch.common.collect.List.of("ct1"),
+                List.of("ct1"),
                 0L,
                 1L,
                 null,
@@ -1420,7 +1381,7 @@ public void testUserDefinedMappingTakesPrecedenceOverDefault() throws Exception
             assertThat(mappings.size(), equalTo(3));
             List<Map<String, Object>> parsedMappings = mappings.stream().map(m -> {
                 try {
-                    return MapperService.parseMapping(new NamedXContentRegistry(org.opensearch.common.collect.List.of()), m.string());
+                    return MapperService.parseMapping(new NamedXContentRegistry(List.of()), m.string());
                 } catch (Exception e) {
                     logger.error(e);
                     fail("failed to parse mappings: " + m.string());
@@ -1428,24 +1389,15 @@ public void testUserDefinedMappingTakesPrecedenceOverDefault() throws Exception
                 }
             }).collect(Collectors.toList());
 
-            Map<String, Object> firstMapping = org.opensearch.common.collect.Map.of(
+            Map<String, Object> firstMapping = Map.of(
                 "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of(TIMESTAMP_FIELD.getName(), org.opensearch.common.collect.Map.of("type", "date"))
-                )
+                Map.of("properties", Map.of(TIMESTAMP_FIELD.getName(), Map.of("type", "date")))
             );
             assertThat(parsedMappings.get(0), equalTo(firstMapping));
 
-            Map<String, Object> secondMapping = org.opensearch.common.collect.Map.of(
+            Map<String, Object> secondMapping = Map.of(
                 "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of(
-                        TIMESTAMP_FIELD.getName(),
-                        org.opensearch.common.collect.Map.of("type", "date_nanos")
-                    )
-                )
+                Map.of("properties", Map.of(TIMESTAMP_FIELD.getName(), Map.of("type", "date_nanos")))
             );
             assertThat(parsedMappings.get(1), equalTo(secondMapping));
         }
@@ -1466,7 +1418,7 @@ public void testUserDefinedMappingTakesPrecedenceOverDefault() throws Exception
                 null
             );
             ComposableIndexTemplate it = new ComposableIndexTemplate(
-                org.opensearch.common.collect.List.of("timeseries*"),
+                List.of("timeseries*"),
                 template,
                 null,
                 0L,
@@ -1486,31 +1438,22 @@ public void testUserDefinedMappingTakesPrecedenceOverDefault() throws Exception
             assertThat(mappings.size(), equalTo(3));
             List<Map<String, Object>> parsedMappings = mappings.stream().map(m -> {
                 try {
-                    return MapperService.parseMapping(new NamedXContentRegistry(org.opensearch.common.collect.List.of()), m.string());
+                    return MapperService.parseMapping(new NamedXContentRegistry(List.of()), m.string());
                 } catch (Exception e) {
                     logger.error(e);
                     fail("failed to parse mappings: " + m.string());
                     return null;
                 }
             }).collect(Collectors.toList());
-            Map<String, Object> firstMapping = org.opensearch.common.collect.Map.of(
+            Map<String, Object> firstMapping = Map.of(
                 "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of(TIMESTAMP_FIELD.getName(), org.opensearch.common.collect.Map.of("type", "date"))
-                )
+                Map.of("properties", Map.of(TIMESTAMP_FIELD.getName(), Map.of("type", "date")))
             );
             assertThat(parsedMappings.get(0), equalTo(firstMapping));
 
-            Map<String, Object> secondMapping = org.opensearch.common.collect.Map.of(
+            Map<String, Object> secondMapping = Map.of(
                 "_doc",
-                org.opensearch.common.collect.Map.of(
-                    "properties",
-                    org.opensearch.common.collect.Map.of(
-                        TIMESTAMP_FIELD.getName(),
-                        org.opensearch.common.collect.Map.of("type", "date_nanos")
-                    )
-                )
+                Map.of("properties", Map.of(TIMESTAMP_FIELD.getName(), Map.of("type", "date_nanos")))
             );
             assertThat(parsedMappings.get(1), equalTo(secondMapping));
         }
@@ -2084,22 +2027,33 @@ public void testLegacyNoopUpdate() {
     }
 
     private static List<Throwable> putTemplate(NamedXContentRegistry xContentRegistry, PutRequest request) {
+        ClusterService clusterService = mock(ClusterService.class);
+        Settings settings = Settings.builder().put(PATH_HOME_SETTING.getKey(), "dummy").build();
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        Metadata metadata = Metadata.builder().build();
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .build();
+        when(clusterService.state()).thenReturn(clusterState);
+        when(clusterService.getSettings()).thenReturn(settings);
+        when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
         MetadataCreateIndexService createIndexService = new MetadataCreateIndexService(
             Settings.EMPTY,
+            clusterService,
             null,
             null,
             null,
-            null,
-            createTestShardLimitService(randomIntBetween(1, 1000)),
+            createTestShardLimitService(randomIntBetween(1, 1000), false),
             new Environment(builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString()).build(), null),
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             null,
             xContentRegistry,
             new SystemIndices(Collections.emptyMap()),
-            true
+            true,
+            new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
         );
         MetadataIndexTemplateService service = new MetadataIndexTemplateService(
-            null,
+            clusterService,
             createIndexService,
             new AliasValidator(),
             null,
@@ -2144,30 +2098,7 @@ public void onFailure(Exception e) {
     }
 
     private MetadataIndexTemplateService getMetadataIndexTemplateService() {
-        IndicesService indicesService = getInstanceFromNode(IndicesService.class);
-        ClusterService clusterService = getInstanceFromNode(ClusterService.class);
-        MetadataCreateIndexService createIndexService = new MetadataCreateIndexService(
-            Settings.EMPTY,
-            clusterService,
-            indicesService,
-            null,
-            null,
-            createTestShardLimitService(randomIntBetween(1, 1000)),
-            new Environment(builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString()).build(), null),
-            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
-            null,
-            xContentRegistry(),
-            new SystemIndices(Collections.emptyMap()),
-            true
-        );
-        return new MetadataIndexTemplateService(
-            clusterService,
-            createIndexService,
-            new AliasValidator(),
-            indicesService,
-            new IndexScopedSettings(Settings.EMPTY, IndexScopedSettings.BUILT_IN_INDEX_SETTINGS),
-            xContentRegistry()
-        );
+        return getInstanceFromNode(MetadataIndexTemplateService.class);
     }
 
     @SuppressWarnings("unchecked")
@@ -2214,7 +2145,7 @@ public static void assertTemplatesEqual(ComposableIndexTemplate actual, Composab
                 Map<String, Object> actualMappings;
                 Map<String, Object> expectedMappings;
                 try (
-                    XContentParser parser = XContentType.JSON.xContent()
+                    XContentParser parser = MediaTypeRegistry.JSON.xContent()
                         .createParser(
                             new NamedXContentRegistry(Collections.emptyList()),
                             LoggingDeprecationHandler.INSTANCE,
@@ -2226,7 +2157,7 @@ public static void assertTemplatesEqual(ComposableIndexTemplate actual, Composab
                     throw new AssertionError(e);
                 }
                 try (
-                    XContentParser parser = XContentType.JSON.xContent()
+                    XContentParser parser = MediaTypeRegistry.JSON.xContent()
                         .createParser(
                             new NamedXContentRegistry(Collections.emptyList()),
                             LoggingDeprecationHandler.INSTANCE,
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeServiceTests.java
index cee95323b8129..ed01f1753e70e 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataIndexUpgradeServiceTests.java
@@ -139,24 +139,21 @@ public void testFailUpgrade() {
                 .put(IndexMetadata.SETTING_VERSION_CREATED, indexCreated)
                 .build()
         );
-        String message = expectThrows(
+        String actualMessage = expectThrows(
             IllegalStateException.class,
             () -> service.upgradeIndexMetadata(metadata, Version.CURRENT.minimumIndexCompatibilityVersion())
         ).getMessage();
-        assertEquals(
-            message,
-            "The index [[foo/BOOM]] was created with version ["
-                + indexCreated
-                + "] "
-                + "but the minimum compatible version is ["
-                + minCompat
-                + "]."
-                + " It should be re-indexed in OpenSearch "
-                + minCompat.major
-                + ".x before upgrading to "
-                + Version.CURRENT.toString()
-                + "."
-        );
+
+        String expectedMessage = "The index [[foo/BOOM]] was created with version ["
+            + indexCreated
+            + "] but the minimum compatible version is "
+            + "OpenSearch 1.0.0 (or Elasticsearch 7.0.0). "
+            + "It should be re-indexed in OpenSearch 1.x "
+            + "(or Elasticsearch 7.x) before upgrading to "
+            + Version.CURRENT
+            + ".";
+
+        assertEquals(expectedMessage, actualMessage);
 
         indexCreated = VersionUtils.randomVersionBetween(random(), minCompat, Version.CURRENT);
         indexUpgraded = VersionUtils.randomVersionBetween(random(), indexCreated, Version.CURRENT);
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataMappingServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataMappingServiceTests.java
index 5388c0a866c5f..d738aa50137bb 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataMappingServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataMappingServiceTests.java
@@ -37,11 +37,11 @@
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.Collection;
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/MetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/MetadataTests.java
index 4e7502ada661f..40eefa6cdbf03 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/MetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/MetadataTests.java
@@ -38,27 +38,28 @@
 import org.opensearch.cluster.DataStreamTestHelper;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.plugins.MapperPlugin;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -77,6 +78,10 @@
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.startsWith;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 public class MetadataTests extends OpenSearchTestCase {
 
@@ -93,7 +98,7 @@ public void testFindAliases() {
             .build();
 
         {
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAliases(new GetAliasesRequest(), Strings.EMPTY_ARRAY);
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAliases(new GetAliasesRequest(), Strings.EMPTY_ARRAY);
             assertThat(aliases.size(), equalTo(0));
         }
         {
@@ -105,7 +110,7 @@ public void testFindAliases() {
                 // replacing with empty aliases behaves as if aliases were unspecified at request building
                 request.replaceAliases(Strings.EMPTY_ARRAY);
             }
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAliases(new GetAliasesRequest(), new String[] { "index" });
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAliases(new GetAliasesRequest(), new String[] { "index" });
             assertThat(aliases.size(), equalTo(1));
             List<AliasMetadata> aliasMetadataList = aliases.get("index");
             assertThat(aliasMetadataList.size(), equalTo(2));
@@ -113,7 +118,7 @@ public void testFindAliases() {
             assertThat(aliasMetadataList.get(1).alias(), equalTo("alias2"));
         }
         {
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAliases(
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAliases(
                 new GetAliasesRequest("alias*"),
                 new String[] { "index" }
             );
@@ -124,7 +129,7 @@ public void testFindAliases() {
             assertThat(aliasMetadataList.get(1).alias(), equalTo("alias2"));
         }
         {
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAliases(
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAliases(
                 new GetAliasesRequest("alias1"),
                 new String[] { "index" }
             );
@@ -134,7 +139,7 @@ public void testFindAliases() {
             assertThat(aliasMetadataList.get(0).alias(), equalTo("alias1"));
         }
         {
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAllAliases(new String[] { "index" });
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAllAliases(new String[] { "index" });
             assertThat(aliases.size(), equalTo(1));
             List<AliasMetadata> aliasMetadataList = aliases.get("index");
             assertThat(aliasMetadataList.size(), equalTo(2));
@@ -142,7 +147,7 @@ public void testFindAliases() {
             assertThat(aliasMetadataList.get(1).alias(), equalTo("alias2"));
         }
         {
-            ImmutableOpenMap<String, List<AliasMetadata>> aliases = metadata.findAllAliases(Strings.EMPTY_ARRAY);
+            final Map<String, List<AliasMetadata>> aliases = metadata.findAllAliases(Strings.EMPTY_ARRAY);
             assertThat(aliases.size(), equalTo(0));
         }
     }
@@ -173,7 +178,7 @@ public void testFindDataStreams() {
         List<Index> allIndices = new ArrayList<>(result.indices);
         allIndices.addAll(result.backingIndices);
         String[] concreteIndices = allIndices.stream().map(Index::getName).collect(Collectors.toList()).toArray(new String[] {});
-        ImmutableOpenMap<String, IndexAbstraction.DataStream> dataStreams = result.metadata.findDataStreams(concreteIndices);
+        final Map<String, IndexAbstraction.DataStream> dataStreams = result.metadata.findDataStreams(concreteIndices);
         assertThat(dataStreams.size(), equalTo(numBackingIndices));
         for (Index backingIndex : result.backingIndices) {
             assertThat(dataStreams.containsKey(backingIndex.getName()), is(true));
@@ -659,19 +664,16 @@ public void testFindMappings() throws IOException {
             .build();
 
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(Strings.EMPTY_ARRAY, MapperPlugin.NOOP_FIELD_FILTER);
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(Strings.EMPTY_ARRAY, MapperPlugin.NOOP_FIELD_FILTER);
             assertEquals(0, mappings.size());
         }
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
-                new String[] { "index1" },
-                MapperPlugin.NOOP_FIELD_FILTER
-            );
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(new String[] { "index1" }, MapperPlugin.NOOP_FIELD_FILTER);
             assertEquals(1, mappings.size());
             assertIndexMappingsNotFiltered(mappings, "index1");
         }
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(
                 new String[] { "index1", "index2" },
                 MapperPlugin.NOOP_FIELD_FILTER
             );
@@ -701,15 +703,12 @@ public void testFindMappingsNoOpFilters() throws IOException {
             .build();
 
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
-                new String[] { "index1" },
-                MapperPlugin.NOOP_FIELD_FILTER
-            );
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(new String[] { "index1" }, MapperPlugin.NOOP_FIELD_FILTER);
             MappingMetadata mappingMetadata = mappings.get("index1");
             assertSame(originalMappingMetadata, mappingMetadata);
         }
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(
                 new String[] { "index1" },
                 index -> field -> randomBoolean()
             );
@@ -726,7 +725,7 @@ public void testFindMappingsWithFilters() throws IOException {
             Map<String, Object> doc = (Map<String, Object>) stringObjectMap.get("_doc");
             try (XContentBuilder builder = JsonXContent.contentBuilder()) {
                 builder.map(doc);
-                mapping = Strings.toString(builder);
+                mapping = builder.toString();
             }
         }
 
@@ -764,21 +763,18 @@ public void testFindMappingsWithFilters() throws IOException {
             .build();
 
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
-                new String[] { "index1", "index2", "index3" },
-                index -> {
-                    if (index.equals("index1")) {
-                        return field -> field.startsWith("name.") == false
-                            && field.startsWith("properties.key.") == false
-                            && field.equals("age") == false
-                            && field.equals("address.location") == false;
-                    }
-                    if (index.equals("index2")) {
-                        return field -> false;
-                    }
-                    return MapperPlugin.NOOP_FIELD_PREDICATE;
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(new String[] { "index1", "index2", "index3" }, index -> {
+                if (index.equals("index1")) {
+                    return field -> field.startsWith("name.") == false
+                        && field.startsWith("properties.key.") == false
+                        && field.equals("age") == false
+                        && field.equals("address.location") == false;
                 }
-            );
+                if (index.equals("index2")) {
+                    return field -> false;
+                }
+                return MapperPlugin.NOOP_FIELD_PREDICATE;
+            });
 
             assertIndexMappingsNoFields(mappings, "index2");
             assertIndexMappingsNotFiltered(mappings, "index3");
@@ -825,7 +821,7 @@ public void testFindMappingsWithFilters() throws IOException {
         }
 
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(
                 new String[] { "index1", "index2", "index3" },
                 index -> field -> (index.equals("index3") && field.endsWith("keyword"))
             );
@@ -860,7 +856,7 @@ public void testFindMappingsWithFilters() throws IOException {
         }
 
         {
-            ImmutableOpenMap<String, MappingMetadata> mappings = metadata.findMappings(
+            final Map<String, MappingMetadata> mappings = metadata.findMappings(
                 new String[] { "index1", "index2", "index3" },
                 index -> field -> (index.equals("index2"))
             );
@@ -881,7 +877,7 @@ private static IndexMetadata.Builder buildIndexMetadata(String name, String alia
     }
 
     @SuppressWarnings("unchecked")
-    private static void assertIndexMappingsNoFields(ImmutableOpenMap<String, MappingMetadata> mappings, String index) {
+    private static void assertIndexMappingsNoFields(final Map<String, MappingMetadata> mappings, String index) {
         MappingMetadata docMapping = mappings.get(index);
         assertNotNull(docMapping);
         Map<String, Object> sourceAsMap = docMapping.getSourceAsMap();
@@ -893,7 +889,7 @@ private static void assertIndexMappingsNoFields(ImmutableOpenMap<String, Mapping
     }
 
     @SuppressWarnings("unchecked")
-    private static void assertIndexMappingsNotFiltered(ImmutableOpenMap<String, MappingMetadata> mappings, String index) {
+    private static void assertIndexMappingsNotFiltered(final Map<String, MappingMetadata> mappings, String index) {
         MappingMetadata docMapping = mappings.get(index);
         assertNotNull(docMapping);
 
@@ -1050,10 +1046,9 @@ public void testBuilderRejectsNullCustom() {
     public void testBuilderRejectsNullInCustoms() {
         final Metadata.Builder builder = Metadata.builder();
         final String key = randomAlphaOfLength(10);
-        final ImmutableOpenMap.Builder<String, Metadata.Custom> mapBuilder = ImmutableOpenMap.builder();
+        final Map<String, Metadata.Custom> mapBuilder = new HashMap<>();
         mapBuilder.put(key, null);
-        final ImmutableOpenMap<String, Metadata.Custom> map = mapBuilder.build();
-        assertThat(expectThrows(NullPointerException.class, () -> builder.customs(map)).getMessage(), containsString(key));
+        assertThat(expectThrows(NullPointerException.class, () -> builder.customs(mapBuilder)).getMessage(), containsString(key));
     }
 
     public void testBuilderRejectsDataStreamThatConflictsWithIndex() {
@@ -1065,7 +1060,7 @@ public void testBuilderRejectsDataStreamThatConflictsWithIndex() {
                 IndexMetadata.builder(dataStreamName).settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1).build(),
                 false
             )
-            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), org.opensearch.common.collect.List.of(idx.getIndex())));
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(idx.getIndex())));
 
         IllegalStateException e = expectThrows(IllegalStateException.class, b::build);
         assertThat(
@@ -1084,7 +1079,7 @@ public void testBuilderRejectsDataStreamThatConflictsWithAlias() {
         IndexMetadata idx = createFirstBackingIndex(dataStreamName).putAlias(AliasMetadata.builder(dataStreamName).build()).build();
         Metadata.Builder b = Metadata.builder()
             .put(idx, false)
-            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), org.opensearch.common.collect.List.of(idx.getIndex())));
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(idx.getIndex())));
 
         IllegalStateException e = expectThrows(IllegalStateException.class, b::build);
         assertThat(
@@ -1107,13 +1102,7 @@ public void testBuilderRejectsDataStreamWithConflictingBackingIndices() {
         Metadata.Builder b = Metadata.builder()
             .put(validIdx, false)
             .put(invalidIdx, false)
-            .put(
-                new DataStream(
-                    dataStreamName,
-                    createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(validIdx.getIndex())
-                )
-            );
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(validIdx.getIndex())));
 
         IllegalStateException e = expectThrows(IllegalStateException.class, b::build);
         assertThat(
@@ -1134,7 +1123,7 @@ public void testBuilderRejectsDataStreamWithConflictingBackingAlias() {
         IndexMetadata idx = createFirstBackingIndex(dataStreamName).putAlias(new AliasMetadata.Builder(conflictingName)).build();
         Metadata.Builder b = Metadata.builder()
             .put(idx, false)
-            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), org.opensearch.common.collect.List.of(idx.getIndex())));
+            .put(new DataStream(dataStreamName, createTimestampField("@timestamp"), List.of(idx.getIndex())));
 
         IllegalStateException e = expectThrows(IllegalStateException.class, b::build);
         assertThat(
@@ -1269,7 +1258,7 @@ public void testValidateDataStreamsThrowsExceptionOnConflict() {
         Index index = standaloneIndexConflictingWithBackingIndices.getIndex();
         indicesLookup.put(index.getName(), new IndexAbstraction.Index(standaloneIndexConflictingWithBackingIndices, null));
 
-        DataStreamMetadata dataStreamMetadata = new DataStreamMetadata(org.opensearch.common.collect.Map.of(dataStreamName, dataStream));
+        DataStreamMetadata dataStreamMetadata = new DataStreamMetadata(Map.of(dataStreamName, dataStream));
 
         IllegalStateException illegalStateException = expectThrows(
             IllegalStateException.class,
@@ -1362,7 +1351,7 @@ public void testValidateDataStreamsAllowsPrefixedBackingIndices() {
                 indicesLookup.put(indexMeta.getIndex().getName(), new IndexAbstraction.Index(indexMeta, dataStreamAbstraction));
             }
         }
-        DataStreamMetadata dataStreamMetadata = new DataStreamMetadata(org.opensearch.common.collect.Map.of(dataStreamName, dataStream));
+        DataStreamMetadata dataStreamMetadata = new DataStreamMetadata(Map.of(dataStreamName, dataStream));
 
         // prefixed indices with a lower generation than the data stream's generation are allowed even if the non-prefixed, matching the
         // data stream backing indices naming pattern, indices are already in the system
@@ -1381,6 +1370,85 @@ public void testValidateDataStreamsForNullDataStreamMetadata() {
         }
     }
 
+    public void testMetadataBuildInvocations() {
+        final Metadata previousMetadata = randomMetadata();
+        Metadata builtMetadata;
+        Metadata.Builder spyBuilder;
+
+        // previous Metadata state was not provided to Builder during assignment - indices lookups should get re-computed
+        spyBuilder = spy(Metadata.builder());
+        builtMetadata = spyBuilder.build();
+        verify(spyBuilder, times(1)).buildMetadataWithRecomputedIndicesLookups();
+        verify(spyBuilder, times(0)).buildMetadataWithPreviousIndicesLookups();
+        compareMetadata(Metadata.EMPTY_METADATA, builtMetadata, true, true, false);
+
+        // no changes in builder method after initialization from previous Metadata - indices lookups should not be re-computed
+        spyBuilder = spy(Metadata.builder(previousMetadata));
+        builtMetadata = spyBuilder.version(previousMetadata.version() + 1).build();
+        verify(spyBuilder, times(0)).buildMetadataWithRecomputedIndicesLookups();
+        verify(spyBuilder, times(1)).buildMetadataWithPreviousIndicesLookups();
+        compareMetadata(previousMetadata, builtMetadata, true, true, true);
+        reset(spyBuilder);
+
+        // adding new index - all indices lookups should get re-computed
+        spyBuilder = spy(Metadata.builder(previousMetadata));
+        String index = "new_index_" + randomAlphaOfLength(3);
+        builtMetadata = spyBuilder.indices(
+            Collections.singletonMap(
+                index,
+                IndexMetadata.builder(index).settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1).build()
+            )
+        ).build();
+        verify(spyBuilder, times(1)).buildMetadataWithRecomputedIndicesLookups();
+        verify(spyBuilder, times(0)).buildMetadataWithPreviousIndicesLookups();
+        compareMetadata(previousMetadata, builtMetadata, false, true, false);
+        reset(spyBuilder);
+
+        // adding new templates - indices lookups should not get recomputed
+        spyBuilder = spy(Metadata.builder(previousMetadata));
+        builtMetadata = spyBuilder.put("component_template_new_" + randomAlphaOfLength(3), ComponentTemplateTests.randomInstance())
+            .put("index_template_v2_new_" + randomAlphaOfLength(3), ComposableIndexTemplateTests.randomInstance())
+            .build();
+        verify(spyBuilder, times(0)).buildMetadataWithRecomputedIndicesLookups();
+        verify(spyBuilder, times(1)).buildMetadataWithPreviousIndicesLookups();
+        compareMetadata(previousMetadata, builtMetadata, true, false, false);
+        reset(spyBuilder);
+
+        // adding new data stream - indices lookups should get re-computed
+        spyBuilder = spy(Metadata.builder(previousMetadata));
+        DataStream dataStream = DataStreamTests.randomInstance();
+        for (Index backingIndex : dataStream.getIndices()) {
+            spyBuilder.put(DataStreamTestHelper.getIndexMetadataBuilderForIndex(backingIndex));
+        }
+        builtMetadata = spyBuilder.put(dataStream).version(previousMetadata.version() + 1).build();
+        verify(spyBuilder, times(1)).buildMetadataWithRecomputedIndicesLookups();
+        verify(spyBuilder, times(0)).buildMetadataWithPreviousIndicesLookups();
+        compareMetadata(previousMetadata, builtMetadata, false, true, true);
+    }
+
+    public void testIsSegmentReplicationEnabled() {
+        final String indexName = "test";
+        Settings.Builder builder = settings(Version.CURRENT).put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+        IndexMetadata.Builder indexMetadataBuilder = IndexMetadata.builder(indexName)
+            .settings(builder)
+            .numberOfShards(1)
+            .numberOfReplicas(1);
+        Metadata.Builder metadataBuilder = Metadata.builder().put(indexMetadataBuilder);
+        Metadata metadata = metadataBuilder.build();
+        assertTrue(metadata.isSegmentReplicationEnabled(indexName));
+    }
+
+    public void testIsSegmentReplicationDisabled() {
+        final String indexName = "test";
+        IndexMetadata.Builder indexMetadataBuilder = IndexMetadata.builder(indexName)
+            .settings(settings(Version.CURRENT))
+            .numberOfShards(1)
+            .numberOfReplicas(1);
+        Metadata.Builder metadataBuilder = Metadata.builder().put(indexMetadataBuilder);
+        Metadata metadata = metadataBuilder.build();
+        assertFalse(metadata.isSegmentReplicationEnabled(indexName));
+    }
+
     public static Metadata randomMetadata() {
         Metadata.Builder md = Metadata.builder()
             .put(buildIndexMetadata("index", "alias", randomBoolean() ? null : randomBoolean()).build(), randomBoolean())
@@ -1452,4 +1520,46 @@ private static class CreateIndexResult {
             this.metadata = metadata;
         }
     }
+
+    private static void compareMetadata(
+        final Metadata previousMetadata,
+        final Metadata newMetadata,
+        final boolean compareIndicesLookups,
+        final boolean compareTemplates,
+        final boolean checkVersionIncrement
+    ) {
+        assertEquals(previousMetadata.clusterUUID(), newMetadata.clusterUUID());
+        assertEquals(previousMetadata.clusterUUIDCommitted(), newMetadata.clusterUUIDCommitted());
+        assertEquals(previousMetadata.coordinationMetadata(), newMetadata.coordinationMetadata());
+        assertEquals(previousMetadata.settings(), newMetadata.settings());
+        assertEquals(previousMetadata.transientSettings(), newMetadata.transientSettings());
+        assertEquals(previousMetadata.persistentSettings(), newMetadata.persistentSettings());
+        assertEquals(previousMetadata.hashesOfConsistentSettings(), newMetadata.hashesOfConsistentSettings());
+
+        if (compareIndicesLookups == true) {
+            assertEquals(previousMetadata.indices(), newMetadata.indices());
+            assertEquals(previousMetadata.getConcreteAllIndices(), newMetadata.getConcreteAllIndices());
+            assertEquals(previousMetadata.getConcreteAllClosedIndices(), newMetadata.getConcreteAllClosedIndices());
+            assertEquals(previousMetadata.getConcreteAllOpenIndices(), newMetadata.getConcreteAllOpenIndices());
+            assertEquals(previousMetadata.getConcreteVisibleIndices(), newMetadata.getConcreteVisibleIndices());
+            assertEquals(previousMetadata.getConcreteVisibleClosedIndices(), newMetadata.getConcreteVisibleClosedIndices());
+            assertEquals(previousMetadata.getConcreteVisibleOpenIndices(), newMetadata.getConcreteVisibleOpenIndices());
+            assertEquals(previousMetadata.getIndicesLookup(), newMetadata.getIndicesLookup());
+            assertEquals(previousMetadata.getCustoms().get(DataStreamMetadata.TYPE), newMetadata.getCustoms().get(DataStreamMetadata.TYPE));
+        }
+
+        if (compareTemplates == true) {
+            assertEquals(previousMetadata.templates(), newMetadata.templates());
+            assertEquals(previousMetadata.templatesV2(), newMetadata.templatesV2());
+            assertEquals(previousMetadata.componentTemplates(), newMetadata.componentTemplates());
+        }
+
+        if (compareIndicesLookups == true && compareTemplates == true) {
+            assertEquals(previousMetadata.getCustoms(), newMetadata.getCustoms());
+        }
+
+        if (checkVersionIncrement == true) {
+            assertEquals(previousMetadata.version() + 1, newMetadata.version());
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceTests.java b/server/src/test/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceTests.java
index 1e52fa380793e..36d984b7eb99b 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/TemplateUpgradeServiceTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.cluster.metadata;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.template.delete.DeleteIndexTemplateRequest;
 import org.opensearch.action.admin.indices.template.put.PutIndexTemplateRequest;
 import org.opensearch.action.support.master.AcknowledgedResponse;
@@ -46,11 +45,11 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -345,7 +344,7 @@ void upgradeTemplates(Map<String, BytesReference> changes, Set<String> deletions
 
             @Override
             Optional<Tuple<Map<String, BytesReference>, Set<String>>> calculateTemplateChanges(
-                ImmutableOpenMap<String, IndexTemplateMetadata> templates
+                final Map<String, IndexTemplateMetadata> templates
             ) {
                 final Optional<Tuple<Map<String, BytesReference>, Set<String>>> ans = super.calculateTemplateChanges(templates);
                 calculateInvocation.release();
@@ -367,7 +366,7 @@ public void clusterChanged(ClusterChangedEvent event) {
                         new DiscoveryNode("node1", "node1", buildNewFakeTransportAddress(), emptyMap(), MASTER_DATA_ROLES, Version.CURRENT)
                     )
                     .localNodeId("node1")
-                    .masterNodeId("node1")
+                    .clusterManagerNodeId("node1")
                     .build()
             )
             .metadata(metadata)
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/ToAndFromJsonMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/ToAndFromJsonMetadataTests.java
index 253018d7f569f..6d8439b7b249c 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/ToAndFromJsonMetadataTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/ToAndFromJsonMetadataTests.java
@@ -35,12 +35,11 @@
 import org.opensearch.Version;
 import org.opensearch.action.admin.indices.rollover.RolloverInfo;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.TestCustomMetadata;
 
@@ -51,6 +50,7 @@
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 
 import static org.opensearch.cluster.DataStreamTestHelper.createFirstBackingIndex;
@@ -128,8 +128,8 @@ public void testSimpleJsonFromAndTo() throws IOException {
             )
             .put(idx1, false)
             .put(idx2, false)
-            .put(new DataStream("data-stream1", createTimestampField("@timestamp"), org.opensearch.common.collect.List.of(idx1.getIndex())))
-            .put(new DataStream("data-stream2", createTimestampField("@timestamp"), org.opensearch.common.collect.List.of(idx2.getIndex())))
+            .put(new DataStream("data-stream1", createTimestampField("@timestamp"), List.of(idx1.getIndex())))
+            .put(new DataStream("data-stream2", createTimestampField("@timestamp"), List.of(idx2.getIndex())))
             .build();
 
         XContentBuilder builder = JsonXContent.contentBuilder();
@@ -274,7 +274,7 @@ public void testToXContentGateway_FlatSettingTrue_ReduceMappingFalse() throws IO
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -370,7 +370,7 @@ public void testToXContentAPI_SameTypeName() throws IOException {
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -440,7 +440,7 @@ public void testToXContentGateway_FlatSettingFalse_ReduceMappingTrue() throws IO
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -545,7 +545,7 @@ public void testToXContentAPI_FlatSettingTrue_ReduceMappingFalse() throws IOExce
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
@@ -656,7 +656,7 @@ public void testToXContentAPI_FlatSettingFalse_ReduceMappingTrue() throws IOExce
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/WeightedRoutingMetadataTests.java b/server/src/test/java/org/opensearch/cluster/metadata/WeightedRoutingMetadataTests.java
new file mode 100644
index 0000000000000..b78d1b56364eb
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/metadata/WeightedRoutingMetadataTests.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.metadata;
+
+import org.opensearch.cluster.routing.WeightedRouting;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+import java.util.Map;
+
+public class WeightedRoutingMetadataTests extends AbstractXContentTestCase<WeightedRoutingMetadata> {
+    @Override
+    protected WeightedRoutingMetadata createTestInstance() {
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, -1);
+        return weightedRoutingMetadata;
+    }
+
+    @Override
+    protected WeightedRoutingMetadata doParseInstance(XContentParser parser) throws IOException {
+        return WeightedRoutingMetadata.fromXContent(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return false;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/metadata/WildcardExpressionResolverTests.java b/server/src/test/java/org/opensearch/cluster/metadata/WildcardExpressionResolverTests.java
index e4027234ac0b4..03807fb5f8c4d 100644
--- a/server/src/test/java/org/opensearch/cluster/metadata/WildcardExpressionResolverTests.java
+++ b/server/src/test/java/org/opensearch/cluster/metadata/WildcardExpressionResolverTests.java
@@ -302,7 +302,7 @@ public void testResolveDataStreams() {
                 new DataStream(
                     dataStreamName,
                     createTimestampField("@timestamp"),
-                    org.opensearch.common.collect.List.of(firstBackingIndexMetadata.getIndex(), secondBackingIndexMetadata.getIndex())
+                    List.of(firstBackingIndexMetadata.getIndex(), secondBackingIndexMetadata.getIndex())
                 )
             );
 
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeFiltersTests.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeFiltersTests.java
index 54f9c46e999d7..691a3cb418f94 100644
--- a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeFiltersTests.java
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeFiltersTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.Version;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleGenerator.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleGenerator.java
new file mode 100644
index 0000000000000..c1aa9390fec94
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleGenerator.java
@@ -0,0 +1,16 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.node;
+
+public class DiscoveryNodeRoleGenerator {
+
+    public static DiscoveryNodeRole createDynamicRole(String roleName) {
+        return new DiscoveryNodeRole.DynamicRole(roleName, roleName, false);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleSettingTests.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleSettingTests.java
index 55c518c62973e..f5935af47fef5 100644
--- a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleSettingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleSettingTests.java
@@ -56,13 +56,8 @@ public void testIsIngestNode() {
     }
 
     public void testIsMasterNode() {
-        // It's used to add MASTER_ROLE into 'roleMap', because MASTER_ROLE is removed from DiscoveryNodeRole.BUILT_IN_ROLES in 2.0.
-        DiscoveryNode.setAdditionalRoles(Collections.emptySet());
-        runRoleTest(DiscoveryNode::isMasterNode, DiscoveryNodeRole.MASTER_ROLE);
-    }
-
-    public void testIsClusterManagerNode() {
-        runRoleTest(DiscoveryNode::isMasterNode, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
+        DiscoveryNode.setDeprecatedMasterRole();
+        runRoleTest(DiscoveryNode::isClusterManagerNode, DiscoveryNodeRole.MASTER_ROLE);
     }
 
     public void testIsRemoteClusterClient() {
@@ -97,5 +92,4 @@ private void runRoleTest(final Predicate<Settings> predicate, final DiscoveryNod
         assertThat(e.getMessage(), startsWith("can not explicitly configure node roles and use legacy role setting"));
         assertNoDeprecationWarnings();
     }
-
 }
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleTests.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleTests.java
index d1acec2832b7c..5f0658f7f110b 100644
--- a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleTests.java
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeRoleTests.java
@@ -33,11 +33,12 @@
 package org.opensearch.cluster.node;
 
 import org.opensearch.common.settings.Setting;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.Locale;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.hasToString;
@@ -117,7 +118,7 @@ public void testDiscoveryNodeRoleEqualsHashCode() {
 
     }
 
-    public void testUnknownRoleIsDistinctFromKnownRoles() {
+    public void testUnknownRoleIsDistinctFromKnownOrDynamicRoles() {
         for (DiscoveryNodeRole buildInRole : DiscoveryNodeRole.BUILT_IN_ROLES) {
             final DiscoveryNodeRole.UnknownRole unknownDataRole = new DiscoveryNodeRole.UnknownRole(
                 buildInRole.roleName(),
@@ -126,6 +127,15 @@ public void testUnknownRoleIsDistinctFromKnownRoles() {
             );
             assertNotEquals(buildInRole, unknownDataRole);
             assertNotEquals(buildInRole.toString(), unknownDataRole.toString());
+            final DiscoveryNodeRole.DynamicRole dynamicRole = new DiscoveryNodeRole.DynamicRole(
+                buildInRole.roleName(),
+                buildInRole.roleNameAbbreviation(),
+                buildInRole.canContainData()
+            );
+            assertNotEquals(buildInRole, dynamicRole);
+            assertNotEquals(buildInRole.toString(), dynamicRole.toString());
+            assertNotEquals(unknownDataRole, dynamicRole);
+            assertNotEquals(unknownDataRole.toString(), dynamicRole.toString());
         }
     }
 
@@ -138,4 +148,15 @@ public void testIsClusterManager() {
         assertTrue(DiscoveryNodeRole.MASTER_ROLE.isClusterManager());
         assertFalse(randomFrom(DiscoveryNodeRole.DATA_ROLE.isClusterManager(), DiscoveryNodeRole.INGEST_ROLE.isClusterManager()));
     }
+
+    public void testRoleNameIsCaseInsensitive() {
+        String roleName = "TestRole";
+        String roleNameAbbreviation = "T";
+        DiscoveryNodeRole unknownRole = new DiscoveryNodeRole.UnknownRole(roleName, roleNameAbbreviation, false);
+        assertEquals(roleName.toLowerCase(Locale.ROOT), unknownRole.roleName());
+        assertEquals(roleNameAbbreviation.toLowerCase(Locale.ROOT), unknownRole.roleNameAbbreviation());
+        DiscoveryNodeRole dynamicRole = new DiscoveryNodeRole.DynamicRole(roleName, roleNameAbbreviation, false);
+        assertEquals(roleName.toLowerCase(Locale.ROOT), dynamicRole.roleName());
+        assertEquals(roleNameAbbreviation.toLowerCase(Locale.ROOT), dynamicRole.roleNameAbbreviation());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeTests.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeTests.java
index 933d9d5f825e9..c2e939bb2f4a5 100644
--- a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeTests.java
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodeTests.java
@@ -35,22 +35,26 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.test.NodeRoles;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.net.InetAddress;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Set;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static org.opensearch.test.NodeRoles.nonRemoteClusterClientNode;
+import static org.opensearch.test.NodeRoles.nonSearchNode;
 import static org.opensearch.test.NodeRoles.remoteClusterClientNode;
+import static org.opensearch.test.NodeRoles.searchNode;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.hasItem;
@@ -174,9 +178,20 @@ public void testDiscoveryNodeIsRemoteClusterClientUnset() {
         runTestDiscoveryNodeIsRemoteClusterClient(nonRemoteClusterClientNode(), false);
     }
 
-    // TODO: Remove the test along with MASTER_ROLE. It is added in 2.0, along with the introduction of CLUSTER_MANAGER_ROLE.
-    public void testSetAdditionalRolesCanAddDeprecatedMasterRole() {
-        DiscoveryNode.setAdditionalRoles(Collections.emptySet());
+    public void testDiscoveryNodeIsSearchSet() {
+        runTestDiscoveryNodeIsSearch(searchNode(), true);
+    }
+
+    public void testDiscoveryNodeIsSearchUnset() {
+        runTestDiscoveryNodeIsSearch(nonSearchNode(), false);
+    }
+
+    // Added in 2.0 temporarily, validate the MASTER_ROLE is in the list of known roles.
+    // MASTER_ROLE was removed from BUILT_IN_ROLES and is imported by setDeprecatedMasterRole(),
+    // as a workaround for making the new CLUSTER_MANAGER_ROLE has got the same abbreviation 'm'.
+    // The test validate this behavior.
+    public void testSetDeprecatedMasterRoleCanAddMasterRole() {
+        DiscoveryNode.setDeprecatedMasterRole();
         assertTrue(DiscoveryNode.getPossibleRoleNames().contains(DiscoveryNodeRole.MASTER_ROLE.roleName()));
     }
 
@@ -190,4 +205,30 @@ private void runTestDiscoveryNodeIsRemoteClusterClient(final Settings settings,
         }
     }
 
+    private void runTestDiscoveryNodeIsSearch(final Settings settings, final boolean expected) {
+        final DiscoveryNode node = DiscoveryNode.createLocal(settings, new TransportAddress(TransportAddress.META_ADDRESS, 9200), "node");
+        assertThat(node.isSearchNode(), equalTo(expected));
+        if (expected) {
+            assertThat(node.getRoles(), hasItem(DiscoveryNodeRole.SEARCH_ROLE));
+        } else {
+            assertThat(node.getRoles(), not(hasItem(DiscoveryNodeRole.SEARCH_ROLE)));
+        }
+    }
+
+    public void testGetRoleFromRoleNameIsCaseInsensitive() {
+        String dataRoleName = "DATA";
+        DiscoveryNodeRole dataNodeRole = DiscoveryNode.getRoleFromRoleName(dataRoleName);
+        assertEquals(DiscoveryNodeRole.DATA_ROLE, dataNodeRole);
+
+        String dynamicRoleName = "TestRole";
+        DiscoveryNodeRole dynamicNodeRole = DiscoveryNode.getRoleFromRoleName(dynamicRoleName);
+        assertEquals(dynamicRoleName.toLowerCase(Locale.ROOT), dynamicNodeRole.roleName());
+        assertEquals(dynamicRoleName.toLowerCase(Locale.ROOT), dynamicNodeRole.roleNameAbbreviation());
+    }
+
+    public void testDiscoveryNodeIsSearchNode() {
+        final Settings settingWithSearchRole = NodeRoles.onlyRole(DiscoveryNodeRole.SEARCH_ROLE);
+        final DiscoveryNode node = DiscoveryNode.createLocal(settingWithSearchRole, buildNewFakeTransportAddress(), "node");
+        assertThat(node.isSearchNode(), equalTo(true));
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodesTests.java b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodesTests.java
index aff9e1cfe7a8c..ede64da1b3c1f 100644
--- a/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodesTests.java
+++ b/server/src/test/java/org/opensearch/cluster/node/DiscoveryNodesTests.java
@@ -33,10 +33,11 @@
 package org.opensearch.cluster.node;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.common.settings.Setting;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
@@ -64,7 +65,7 @@ public class DiscoveryNodesTests extends OpenSearchTestCase {
 
     public void testResolveNodeByIdOrName() {
         DiscoveryNodes discoveryNodes = buildDiscoveryNodes();
-        DiscoveryNode[] nodes = discoveryNodes.getNodes().values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] nodes = discoveryNodes.getNodes().values().toArray(new DiscoveryNode[0]);
         DiscoveryNode node = randomFrom(nodes);
         DiscoveryNode resolvedNode = discoveryNodes.resolveNode(randomBoolean() ? node.getId() : node.getName());
         assertThat(resolvedNode.getId(), equalTo(node.getId()));
@@ -108,34 +109,31 @@ public void testAll() {
         assertThat(discoveryNodes.resolveNodes(new String[0]), arrayContainingInAnyOrder(allNodes));
         assertThat(discoveryNodes.resolveNodes("_all"), arrayContainingInAnyOrder(allNodes));
 
-        final String[] nonMasterNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
-            .map(n -> n.value)
-            .filter(n -> n.isMasterNode() == false)
+        final String[] nonClusterManagerNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
+            .filter(n -> n.isClusterManagerNode() == false)
             .map(DiscoveryNode::getId)
             .toArray(String[]::new);
-        assertThat(discoveryNodes.resolveNodes("_all", "master:false"), arrayContainingInAnyOrder(nonMasterNodes));
+        assertThat(discoveryNodes.resolveNodes("_all", "cluster_manager:false"), arrayContainingInAnyOrder(nonClusterManagerNodes));
 
-        assertThat(discoveryNodes.resolveNodes("master:false", "_all"), arrayContainingInAnyOrder(allNodes));
+        assertThat(discoveryNodes.resolveNodes("cluster_manager:false", "_all"), arrayContainingInAnyOrder(allNodes));
     }
 
     public void testCoordinatorOnlyNodes() {
         final DiscoveryNodes discoveryNodes = buildDiscoveryNodes();
 
         final String[] coordinatorOnlyNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
-            .map(n -> n.value)
-            .filter(n -> n.isDataNode() == false && n.isIngestNode() == false && n.isMasterNode() == false)
+            .filter(n -> n.isDataNode() == false && n.isIngestNode() == false && n.isClusterManagerNode() == false)
             .map(DiscoveryNode::getId)
             .toArray(String[]::new);
 
         final String[] nonCoordinatorOnlyNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
-            .map(n -> n.value)
-            .filter(n -> n.isMasterNode() || n.isDataNode() || n.isIngestNode())
+            .filter(n -> n.isClusterManagerNode() || n.isDataNode() || n.isIngestNode())
             .map(DiscoveryNode::getId)
             .toArray(String[]::new);
 
         assertThat(discoveryNodes.resolveNodes("coordinating_only:true"), arrayContainingInAnyOrder(coordinatorOnlyNodes));
         assertThat(
-            discoveryNodes.resolveNodes("_all", "data:false", "ingest:false", "master:false"),
+            discoveryNodes.resolveNodes("_all", "data:false", "ingest:false", "cluster_manager:false"),
             arrayContainingInAnyOrder(coordinatorOnlyNodes)
         );
         assertThat(discoveryNodes.resolveNodes("_all", "coordinating_only:false"), arrayContainingInAnyOrder(nonCoordinatorOnlyNodes));
@@ -154,14 +152,14 @@ public void testResolveNodesIds() {
             }
         }
         int numNodeIds = randomIntBetween(0, 3);
-        String[] nodeIds = discoveryNodes.getNodes().keys().toArray(String.class);
+        String[] nodeIds = discoveryNodes.getNodes().keySet().toArray(new String[0]);
         for (int i = 0; i < numNodeIds; i++) {
             String nodeId = randomFrom(nodeIds);
             nodeSelectors.add(nodeId);
             expectedNodeIdsSet.add(nodeId);
         }
         int numNodeNames = randomIntBetween(0, 3);
-        DiscoveryNode[] nodes = discoveryNodes.getNodes().values().toArray(DiscoveryNode.class);
+        DiscoveryNode[] nodes = discoveryNodes.getNodes().values().toArray(new DiscoveryNode[0]);
         for (int i = 0; i < numNodeNames; i++) {
             DiscoveryNode discoveryNode = randomFrom(nodes);
             nodeSelectors.add(discoveryNode.getName());
@@ -175,15 +173,15 @@ public void testResolveNodesIds() {
         assertThat(resolvedNodesIds, equalTo(expectedNodesIds));
     }
 
-    public void testMastersFirst() {
+    public void testClusterManagersFirst() {
         final List<DiscoveryNode> inputNodes = randomNodes(10);
         final DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
         inputNodes.forEach(discoBuilder::add);
-        final List<DiscoveryNode> returnedNodes = discoBuilder.build().mastersFirstStream().collect(Collectors.toList());
+        final List<DiscoveryNode> returnedNodes = discoBuilder.build().clusterManagersFirstStream().collect(Collectors.toList());
         assertEquals(returnedNodes.size(), inputNodes.size());
         assertEquals(new HashSet<>(returnedNodes), new HashSet<>(inputNodes));
         final List<DiscoveryNode> sortedNodes = new ArrayList<>(returnedNodes);
-        Collections.sort(sortedNodes, Comparator.comparing(n -> n.isMasterNode() == false));
+        Collections.sort(sortedNodes, Comparator.comparing(n -> n.isClusterManagerNode() == false));
         assertEquals(sortedNodes, returnedNodes);
     }
 
@@ -254,19 +252,19 @@ public void testDeltas() {
             nodesB.add(node);
         }
 
-        DiscoveryNode masterA = randomBoolean() ? null : RandomPicks.randomFrom(random(), nodesA);
-        DiscoveryNode masterB = randomBoolean() ? null : RandomPicks.randomFrom(random(), nodesB);
+        DiscoveryNode clusterManagerA = randomBoolean() ? null : RandomPicks.randomFrom(random(), nodesA);
+        DiscoveryNode clusterManagerB = randomBoolean() ? null : RandomPicks.randomFrom(random(), nodesB);
 
         DiscoveryNodes.Builder builderA = DiscoveryNodes.builder();
         nodesA.stream().forEach(builderA::add);
-        final String masterAId = masterA == null ? null : masterA.getId();
-        builderA.masterNodeId(masterAId);
+        final String clusterManagerAId = clusterManagerA == null ? null : clusterManagerA.getId();
+        builderA.clusterManagerNodeId(clusterManagerAId);
         builderA.localNodeId(RandomPicks.randomFrom(random(), nodesA).getId());
 
         DiscoveryNodes.Builder builderB = DiscoveryNodes.builder();
         nodesB.stream().forEach(builderB::add);
-        final String masterBId = masterB == null ? null : masterB.getId();
-        builderB.masterNodeId(masterBId);
+        final String clusterManagerBId = clusterManagerB == null ? null : clusterManagerB.getId();
+        builderB.clusterManagerNodeId(clusterManagerBId);
         builderB.localNodeId(RandomPicks.randomFrom(random(), nodesB).getId());
 
         final DiscoveryNodes discoNodesA = builderA.build();
@@ -276,21 +274,21 @@ public void testDeltas() {
 
         DiscoveryNodes.Delta delta = discoNodesB.delta(discoNodesA);
 
-        if (masterA == null) {
-            assertThat(delta.previousMasterNode(), nullValue());
+        if (clusterManagerA == null) {
+            assertThat(delta.previousClusterManagerNode(), nullValue());
         } else {
-            assertThat(delta.previousMasterNode().getId(), equalTo(masterAId));
+            assertThat(delta.previousClusterManagerNode().getId(), equalTo(clusterManagerAId));
         }
-        if (masterB == null) {
-            assertThat(delta.newMasterNode(), nullValue());
+        if (clusterManagerB == null) {
+            assertThat(delta.newClusterManagerNode(), nullValue());
         } else {
-            assertThat(delta.newMasterNode().getId(), equalTo(masterBId));
+            assertThat(delta.newClusterManagerNode().getId(), equalTo(clusterManagerBId));
         }
 
-        if (Objects.equals(masterAId, masterBId)) {
-            assertFalse(delta.masterNodeChanged());
+        if (Objects.equals(clusterManagerAId, clusterManagerBId)) {
+            assertFalse(delta.clusterManagerNodeChanged());
         } else {
-            assertTrue(delta.masterNodeChanged());
+            assertTrue(delta.clusterManagerNodeChanged());
         }
 
         Set<DiscoveryNode> newNodes = new HashSet<>(nodesB);
@@ -306,6 +304,30 @@ public void testDeltas() {
         assertThat(delta.removedNodes().size(), equalTo(removedNodes.size()));
     }
 
+    // Validate using the deprecated 'master' role in the node filter can get correct result.
+    public void testDeprecatedMasterNodeFilter() {
+        final DiscoveryNodes discoveryNodes = buildDiscoveryNodes();
+
+        final String[] allNodes = StreamSupport.stream(discoveryNodes.spliterator(), false)
+            .map(DiscoveryNode::getId)
+            .toArray(String[]::new);
+
+        final String[] clusterManagerNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
+            .filter(n -> n.isClusterManagerNode() == true)
+            .map(DiscoveryNode::getId)
+            .toArray(String[]::new);
+
+        final String[] nonClusterManagerNodes = StreamSupport.stream(discoveryNodes.getNodes().values().spliterator(), false)
+            .filter(n -> n.isClusterManagerNode() == false)
+            .map(DiscoveryNode::getId)
+            .toArray(String[]::new);
+
+        assertThat(discoveryNodes.resolveNodes("cluster_manager:true"), arrayContainingInAnyOrder(clusterManagerNodes));
+        assertThat(discoveryNodes.resolveNodes("master:true"), arrayContainingInAnyOrder(clusterManagerNodes));
+        assertThat(discoveryNodes.resolveNodes("_all", "master:false"), arrayContainingInAnyOrder(nonClusterManagerNodes));
+        assertThat(discoveryNodes.resolveNodes("master:false", "_all"), arrayContainingInAnyOrder(allNodes));
+    }
+
     private static AtomicInteger idGenerator = new AtomicInteger();
 
     private static List<DiscoveryNode> randomNodes(final int numNodes) {
@@ -340,7 +362,7 @@ private static DiscoveryNodes buildDiscoveryNodes() {
             discoBuilder = discoBuilder.add(node);
         }
         discoBuilder.localNodeId(randomFrom(nodesList).getId());
-        discoBuilder.masterNodeId(randomFrom(nodesList).getId());
+        discoBuilder.clusterManagerNodeId(randomFrom(nodesList).getId());
         return discoBuilder.build();
     }
 
@@ -358,7 +380,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
         ELECTED_MASTER("_master") {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
-                return Collections.singleton(nodes.getMasterNodeId());
+                return Collections.singleton(nodes.getClusterManagerNodeId());
             }
         },
         // TODO: Remove this element after removing DiscoveryNodeRole.MASTER_ROLE
@@ -366,7 +388,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getMasterNodes().keysIt().forEachRemaining(ids::add);
+                nodes.getClusterManagerNodes().keySet().iterator().forEachRemaining(ids::add);
                 return ids;
             }
         },
@@ -374,7 +396,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getMasterNodes().keysIt().forEachRemaining(ids::add);
+                nodes.getClusterManagerNodes().keySet().iterator().forEachRemaining(ids::add);
                 return ids;
             }
         },
@@ -382,7 +404,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getDataNodes().keysIt().forEachRemaining(ids::add);
+                nodes.getDataNodes().keySet().iterator().forEachRemaining(ids::add);
                 return ids;
             }
         },
@@ -390,7 +412,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getIngestNodes().keysIt().forEachRemaining(ids::add);
+                nodes.getIngestNodes().keySet().iterator().forEachRemaining(ids::add);
                 return ids;
             }
         },
@@ -398,7 +420,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getCoordinatingOnlyNodes().keysIt().forEachRemaining(ids::add);
+                nodes.getCoordinatingOnlyNodes().keySet().iterator().forEachRemaining(ids::add);
                 return ids;
             }
         },
@@ -406,7 +428,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getNodes().valuesIt().forEachRemaining(node -> {
+                nodes.getNodes().values().iterator().forEachRemaining(node -> {
                     if ("value".equals(node.getAttributes().get("attr"))) {
                         ids.add(node.getId());
                     }
@@ -418,7 +440,7 @@ Set<String> matchingNodeIds(DiscoveryNodes nodes) {
             @Override
             Set<String> matchingNodeIds(DiscoveryNodes nodes) {
                 Set<String> ids = new HashSet<>();
-                nodes.getNodes().valuesIt().forEachRemaining(node -> {
+                nodes.getNodes().values().iterator().forEachRemaining(node -> {
                     if (node.getRoles().stream().anyMatch(role -> role.roleName().equals("custom_role"))) {
                         ids.add(node.getId());
                     }
@@ -469,7 +491,7 @@ public void testMaxMinNodeVersion() {
             )
         );
         discoBuilder.localNodeId("name_1");
-        discoBuilder.masterNodeId("name_2");
+        discoBuilder.clusterManagerNodeId("name_2");
         DiscoveryNodes build = discoBuilder.build();
         assertEquals(Version.fromString("1.1.0"), build.getMaxNodeVersion());
         assertEquals(LegacyESVersion.fromString("5.1.0"), build.getMinNodeVersion());
@@ -497,7 +519,7 @@ public void testNodeExistsWithBWCVersion() {
         discoBuilder.add(node_2);
 
         discoBuilder.localNodeId("name_1");
-        discoBuilder.masterNodeId("name_2");
+        discoBuilder.clusterManagerNodeId("name_2");
         DiscoveryNodes build = discoBuilder.build();
         assertTrue(build.nodeExistsWithBWCVersion(buildDiscoveryNodeFromExisting(node_1, Version.CURRENT)));
         assertFalse(build.nodeExistsWithBWCVersion(buildDiscoveryNodeFromExisting(node_2, LegacyESVersion.fromString("7.10.2"))));
diff --git a/server/src/test/java/org/opensearch/cluster/routing/AllocationIdTests.java b/server/src/test/java/org/opensearch/cluster/routing/AllocationIdTests.java
index e266eacdc0320..20b2a80a3f4ce 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/AllocationIdTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/AllocationIdTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.cluster.routing;
 
 import org.opensearch.cluster.routing.RecoverySource.ExistingStoreRecoverySource;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -142,6 +142,24 @@ public void testMoveToUnassigned() {
         assertThat(shard.allocationId(), nullValue());
     }
 
+    public void testMovePrimaryToReplica() {
+        logger.info("-- build started shard");
+        ShardRouting shard = ShardRouting.newUnassigned(
+            new ShardId("test", "_na_", 0),
+            true,
+            ExistingStoreRecoverySource.INSTANCE,
+            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, null)
+        );
+        shard = shard.initialize("node1", null, -1);
+        shard = shard.moveToStarted();
+        AllocationId originalAllocationId = shard.allocationId();
+
+        logger.info("-- move to replica");
+        shard = shard.moveActivePrimaryToReplica();
+        assertNotNull(shard.allocationId());
+        assertEquals(originalAllocationId, shard.allocationId());
+    }
+
     public void testSerialization() throws IOException {
         AllocationId allocationId = AllocationId.newInitializing();
         if (randomBoolean()) {
diff --git a/server/src/test/java/org/opensearch/cluster/routing/BatchedRerouteServiceTests.java b/server/src/test/java/org/opensearch/cluster/routing/BatchedRerouteServiceTests.java
index db93aa39c2da7..a22369c92bd35 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/BatchedRerouteServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/BatchedRerouteServiceTests.java
@@ -32,7 +32,6 @@
 package org.opensearch.cluster.routing;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.coordination.FailedToCommitClusterStateException;
@@ -40,6 +39,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
 import org.opensearch.common.Randomness;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
@@ -101,7 +101,7 @@ public void testReroutesWhenRequested() throws InterruptedException {
 
     public void testBatchesReroutesTogetherAtPriorityOfHighestSubmittedReroute() throws BrokenBarrierException, InterruptedException {
         final CyclicBarrier cyclicBarrier = new CyclicBarrier(2);
-        clusterService.submitStateUpdateTask("block master service", new ClusterStateUpdateTask() {
+        clusterService.submitStateUpdateTask("block cluster-manager service", new ClusterStateUpdateTask() {
             @Override
             public ClusterState execute(ClusterState currentState) throws Exception {
                 cyclicBarrier.await(); // notify test that we are blocked
@@ -115,7 +115,7 @@ public void onFailure(String source, Exception e) {
             }
         });
 
-        cyclicBarrier.await(); // wait for master thread to be blocked
+        cyclicBarrier.await(); // wait for cluster-manager thread to be blocked
 
         final AtomicBoolean rerouteExecuted = new AtomicBoolean();
         final BatchedRerouteService batchedRerouteService = new BatchedRerouteService(clusterService, (s, r) -> {
@@ -194,7 +194,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         actions.forEach(threadPool.generic()::execute);
         assertTrue(tasksSubmittedCountDown.await(10, TimeUnit.SECONDS));
 
-        cyclicBarrier.await(); // allow master thread to continue;
+        cyclicBarrier.await(); // allow cluster-manager thread to continue;
         assertTrue(tasksCompletedCountDown.await(10, TimeUnit.SECONDS)); // wait for reroute to complete
         assertTrue(rerouteExecuted.get()); // see above for assertion that it's only called once
     }
@@ -223,7 +223,7 @@ public void testNotifiesOnFailure() throws InterruptedException {
                 }
             }));
             if (rarely()) {
-                clusterService.getMasterService()
+                clusterService.getClusterManagerService()
                     .setClusterStatePublisher(
                         randomBoolean()
                             ? ClusterServiceUtils.createClusterStatePublisher(clusterService.getClusterApplierService())
@@ -237,7 +237,10 @@ public void testNotifiesOnFailure() throws InterruptedException {
                 clusterService.getClusterApplierService().onNewClusterState("simulated", () -> {
                     ClusterState state = clusterService.state();
                     return ClusterState.builder(state)
-                        .nodes(DiscoveryNodes.builder(state.nodes()).masterNodeId(randomBoolean() ? null : state.nodes().getLocalNodeId()))
+                        .nodes(
+                            DiscoveryNodes.builder(state.nodes())
+                                .clusterManagerNodeId(randomBoolean() ? null : state.nodes().getLocalNodeId())
+                        )
                         .build();
                 }, (source, e) -> {});
             }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/DelayedAllocationServiceTests.java b/server/src/test/java/org/opensearch/cluster/routing/DelayedAllocationServiceTests.java
index 1f45c5c1dfce4..6611554004639 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/DelayedAllocationServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/DelayedAllocationServiceTests.java
@@ -64,8 +64,8 @@
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 import static org.hamcrest.Matchers.equalTo;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
@@ -83,7 +83,7 @@ public void createDelayedAllocationService() {
         threadPool = new TestThreadPool(getTestName());
         clusterService = mock(ClusterService.class);
         allocationService = createAllocationService(Settings.EMPTY, new DelayedShardsMockGatewayAllocator());
-        when(clusterService.getSettings()).thenReturn(NodeRoles.masterOnlyNode());
+        when(clusterService.getSettings()).thenReturn(NodeRoles.clusterManagerOnlyNode());
         delayedAllocationService = new TestDelayAllocationService(threadPool, clusterService, allocationService);
         verify(clusterService).addListener(delayedAllocationService);
         verify(clusterService).getSettings();
@@ -108,7 +108,7 @@ public void testNoDelayedUnassigned() throws Exception {
             .routingTable(RoutingTable.builder().addAsNew(metadata.index("test")).build())
             .build();
         clusterState = ClusterState.builder(clusterState)
-            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")).localNodeId("node1").masterNodeId("node1"))
+            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")).localNodeId("node1").clusterManagerNodeId("node1"))
             .build();
         clusterState = allocationService.reroute(clusterState, "reroute");
         // starting primaries
@@ -154,7 +154,7 @@ public void testDelayedUnassignedScheduleReroute() throws Exception {
             .routingTable(RoutingTable.builder().addAsNew(metadata.index("test")).build())
             .build();
         clusterState = ClusterState.builder(clusterState)
-            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")).localNodeId("node1").masterNodeId("node1"))
+            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")).localNodeId("node1").clusterManagerNodeId("node1"))
             .build();
         final long baseTimestampNanos = System.nanoTime();
         allocationService.setNanoTimeOverride(baseTimestampNanos);
@@ -264,7 +264,7 @@ public void testDelayedUnassignedScheduleRerouteAfterDelayedReroute() throws Exc
                 DiscoveryNodes.builder()
                     .add(newNode("node0", singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)))
                     .localNodeId("node0")
-                    .masterNodeId("node0")
+                    .clusterManagerNodeId("node0")
                     .add(newNode("node1"))
                     .add(newNode("node2"))
                     .add(newNode("node3"))
@@ -449,7 +449,7 @@ public void testDelayedUnassignedScheduleRerouteRescheduledOnShorterDelay() thro
                     .add(newNode("node3"))
                     .add(newNode("node4"))
                     .localNodeId("node1")
-                    .masterNodeId("node1")
+                    .clusterManagerNodeId("node1")
             )
             .build();
         final long nodeLeftTimestampNanos = System.nanoTime();
@@ -556,7 +556,7 @@ private TestDelayAllocationService(ThreadPool threadPool, ClusterService cluster
         }
 
         @Override
-        protected void assertClusterOrMasterStateThread() {
+        protected void assertClusterOrClusterManagerStateThread() {
             // do not check this in the unit tests
         }
 
diff --git a/server/src/test/java/org/opensearch/cluster/routing/FailAwareWeightedRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/FailAwareWeightedRoutingTests.java
new file mode 100644
index 0000000000000..9000f11ef22bc
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/FailAwareWeightedRoutingTests.java
@@ -0,0 +1,391 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.Version;
+import org.opensearch.action.OriginalIndicesTests;
+import org.opensearch.action.search.SearchShardIterator;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.search.SearchShardTarget;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.NodeNotConnectedException;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_CREATION_DATE;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
+
+public class FailAwareWeightedRoutingTests extends OpenSearchTestCase {
+
+    private ClusterState setUpCluster() {
+        return setUpCluster(Settings.EMPTY);
+    }
+
+    private ClusterState setUpCluster(Settings transientSettings) {
+        ClusterState clusterState = ClusterState.builder(new ClusterName("test")).build();
+
+        // set up nodes
+        DiscoveryNode nodeA = new DiscoveryNode(
+            "node_zone_a",
+            buildNewFakeTransportAddress(),
+            singletonMap("zone", "a"),
+            Collections.singleton(DiscoveryNodeRole.DATA_ROLE),
+            Version.CURRENT
+        );
+        DiscoveryNode nodeB = new DiscoveryNode(
+            "node_zone_b",
+            buildNewFakeTransportAddress(),
+            singletonMap("zone", "b"),
+            Collections.singleton(DiscoveryNodeRole.DATA_ROLE),
+            Version.CURRENT
+        );
+        DiscoveryNode nodeC = new DiscoveryNode(
+            "node_zone_c",
+            buildNewFakeTransportAddress(),
+            singletonMap("zone", "c"),
+            Collections.singleton(DiscoveryNodeRole.DATA_ROLE),
+            Version.CURRENT
+        );
+
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+
+        nodeBuilder.add(nodeA);
+        nodeBuilder.add(nodeB);
+        nodeBuilder.add(nodeC);
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+
+        // set up weighted routing weights
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata()).transientSettings(transientSettings);
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+
+        return clusterState;
+
+    }
+
+    public void testFindNextWithoutFailOpen() throws IOException {
+
+        ClusterState clusterState = setUpCluster();
+        AtomicInteger shardSkipped = new AtomicInteger();
+        // set up index
+        IndexMetadata indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+
+        ShardRouting shardRoutingA = TestShardRouting.newShardRouting("test", 0, "node_zone_a", true, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingB = TestShardRouting.newShardRouting("test", 0, "node_zone_b", false, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingC = TestShardRouting.newShardRouting("test", 0, "node_zone_c", false, ShardRoutingState.STARTED);
+
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+        IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+        indexShardRoutingBuilder.addShard(shardRoutingA);
+        indexShardRoutingBuilder.addShard(shardRoutingB);
+        indexShardRoutingBuilder.addShard(shardRoutingC);
+
+        indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+        routingTableBuilder.add(indexRoutingTableBuilder.build());
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTableBuilder.build()).build();
+
+        List<ShardRouting> shardRoutings = new ArrayList<>();
+        shardRoutings.add(shardRoutingA);
+        shardRoutings.add(shardRoutingB);
+        shardRoutings.add(shardRoutingC);
+
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
+        SearchShardIterator searchShardIterator = new SearchShardIterator(
+            clusterAlias,
+            shardId,
+            shardRoutings,
+            OriginalIndicesTests.randomOriginalIndices()
+        );
+
+        searchShardIterator.nextOrNull();
+        searchShardIterator.nextOrNull();
+
+        // fail open is not executed since fail open conditions don't met
+        SearchShardTarget next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNull(next);
+        assertEquals(1, shardSkipped.get());
+    }
+
+    public void testFindNextWithJustOneShardInStandbyZone() throws IOException {
+        ClusterState clusterState = setUpCluster();
+
+        AtomicInteger shardSkipped = new AtomicInteger();
+        // set up index
+        IndexMetadata indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+
+        ShardRouting shardRoutingA = TestShardRouting.newShardRouting("test", 0, "node_zone_a", true, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingB = TestShardRouting.newShardRouting("test", 0, "node_zone_b", false, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingC = TestShardRouting.newShardRouting("test", 0, "node_zone_c", false, ShardRoutingState.STARTED);
+
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+        IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+        indexShardRoutingBuilder.addShard(shardRoutingA);
+        indexShardRoutingBuilder.addShard(shardRoutingB);
+        indexShardRoutingBuilder.addShard(shardRoutingC);
+
+        indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+        routingTableBuilder.add(indexRoutingTableBuilder.build());
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTableBuilder.build()).build();
+
+        List<ShardRouting> shardRoutings = new ArrayList<>();
+        shardRoutings.add(shardRoutingC);
+
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
+        SearchShardIterator searchShardIterator = new SearchShardIterator(
+            clusterAlias,
+            shardId,
+            shardRoutings,
+            OriginalIndicesTests.randomOriginalIndices()
+        );
+
+        // fail open is not executed since fail open conditions don't met
+        SearchShardTarget next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNotNull(next);
+        next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNull(next);
+        assertEquals(0, shardSkipped.get());
+    }
+
+    public void testFindNextWithIgnoreWeightedRoutingTrue() throws IOException {
+        ClusterState clusterState = setUpCluster(Settings.builder().put("cluster.routing.ignore_weighted_routing", true).build());
+
+        AtomicInteger shardSkipped = new AtomicInteger();
+        // set up index
+        IndexMetadata indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+
+        ShardRouting shardRoutingA = TestShardRouting.newShardRouting("test", 0, "node_zone_a", true, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingB = TestShardRouting.newShardRouting("test", 0, "node_zone_b", false, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingC = TestShardRouting.newShardRouting("test", 0, "node_zone_c", false, ShardRoutingState.STARTED);
+
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+        IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+        indexShardRoutingBuilder.addShard(shardRoutingA);
+        indexShardRoutingBuilder.addShard(shardRoutingB);
+        indexShardRoutingBuilder.addShard(shardRoutingC);
+
+        indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+        routingTableBuilder.add(indexRoutingTableBuilder.build());
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTableBuilder.build()).build();
+
+        List<ShardRouting> shardRoutings = new ArrayList<>();
+        shardRoutings.add(shardRoutingA);
+        shardRoutings.add(shardRoutingB);
+        shardRoutings.add(shardRoutingC);
+
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
+        SearchShardIterator searchShardIterator = new SearchShardIterator(
+            clusterAlias,
+            shardId,
+            shardRoutings,
+            OriginalIndicesTests.randomOriginalIndices()
+        );
+
+        // fail open is not executed since fail open conditions don't met
+        SearchShardTarget next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNotNull(next);
+        next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNotNull(next);
+        next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNotNull(next);
+        next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardSkipped.incrementAndGet());
+        assertNull(next);
+        assertEquals(0, shardSkipped.get());
+    }
+
+    public void testFindNextWithFailOpenDueTo5xx() throws IOException {
+
+        ClusterState clusterState = setUpCluster();
+
+        // set up index
+        IndexMetadata indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+
+        ShardRouting shardRoutingA = TestShardRouting.newShardRouting("test", 0, "node_zone_a", true, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingB = TestShardRouting.newShardRouting("test", 0, "node_zone_b", false, ShardRoutingState.STARTED);
+        ShardRouting shardRoutingC = TestShardRouting.newShardRouting("test", 0, "node_zone_c", false, ShardRoutingState.STARTED);
+
+        List<ShardRouting> shardRoutings = new ArrayList<>();
+        shardRoutings.add(shardRoutingA);
+        shardRoutings.add(shardRoutingB);
+        shardRoutings.add(shardRoutingC);
+
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+        IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+
+        indexShardRoutingBuilder.addShard(shardRoutingA);
+        indexShardRoutingBuilder.addShard(shardRoutingB);
+        indexShardRoutingBuilder.addShard(shardRoutingC);
+
+        indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+
+        routingTableBuilder.add(indexRoutingTableBuilder.build());
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTableBuilder.build()).build();
+
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
+
+        SearchShardIterator searchShardIterator = new SearchShardIterator(
+            clusterAlias,
+            shardId,
+            shardRoutings,
+            OriginalIndicesTests.randomOriginalIndices()
+        );
+
+        searchShardIterator.nextOrNull();
+        searchShardIterator.nextOrNull();
+
+        // Node in zone b is disconnected
+        DiscoveryNode node = clusterState.nodes().get("node_zone_b");
+        // fail open is executed and shard present in node with weighted routing weight zero is returned
+        SearchShardTarget next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new NodeNotConnectedException(node, "Node is not " + "connected"), () -> {});
+        assertNotNull(next);
+        assertEquals("node_zone_c", next.getNodeId());
+    }
+
+    public void testFindNextWithFailOpenDueToUnassignedShard() throws IOException {
+
+        ClusterState clusterState = setUpCluster();
+        AtomicInteger shardsSkipped = new AtomicInteger();
+        IndexMetadata indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, 1)
+                    .put(SETTING_NUMBER_OF_REPLICAS, 2)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+        ShardRouting shardRoutingB = TestShardRouting.newShardRouting("test", 0, "node_zone_b", true, ShardRoutingState.STARTED);
+
+        ShardRouting shardRoutingA = TestShardRouting.newShardRouting("test", 0, null, false, ShardRoutingState.UNASSIGNED);
+
+        ShardRouting shardRoutingC = TestShardRouting.newShardRouting("test", 0, "node_zone_c", false, ShardRoutingState.STARTED);
+
+        List<ShardRouting> shardRoutings = new ArrayList<>();
+        shardRoutings.add(shardRoutingA);
+        shardRoutings.add(shardRoutingB);
+        shardRoutings.add(shardRoutingC);
+
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+        IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+
+        indexShardRoutingBuilder.addShard(shardRoutingA);
+        indexShardRoutingBuilder.addShard(shardRoutingB);
+        indexShardRoutingBuilder.addShard(shardRoutingC);
+
+        indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+
+        routingTableBuilder.add(indexRoutingTableBuilder.build());
+        clusterState = ClusterState.builder(clusterState).routingTable(routingTableBuilder.build()).build();
+
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
+
+        SearchShardIterator searchShardIterator = new SearchShardIterator(
+            clusterAlias,
+            shardId,
+            shardRoutings,
+            OriginalIndicesTests.randomOriginalIndices()
+        );
+
+        searchShardIterator.nextOrNull();
+        searchShardIterator.nextOrNull();
+
+        // since there is an unassigned shard in the cluster, fail open is executed and shard present in node with
+        // weighted routing weight zero is returned
+        SearchShardTarget next = FailAwareWeightedRouting.getInstance()
+            .findNext(searchShardIterator, clusterState, new OpenSearchRejectedExecutionException(), () -> shardsSkipped.incrementAndGet());
+        assertNotNull(next);
+        assertEquals("node_zone_c", next.getNodeId());
+        assertEquals(1, shardsSkipped.incrementAndGet());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/GroupShardsIteratorTests.java b/server/src/test/java/org/opensearch/cluster/routing/GroupShardsIteratorTests.java
index fb9e356b3420d..1cb27ebc77fdd 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/GroupShardsIteratorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/GroupShardsIteratorTests.java
@@ -35,8 +35,8 @@
 import org.apache.lucene.util.CollectionUtil;
 import org.opensearch.action.OriginalIndicesTests;
 import org.opensearch.action.search.SearchShardIterator;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/IndexShardRoutingTableTests.java b/server/src/test/java/org/opensearch/cluster/routing/IndexShardRoutingTableTests.java
index 5a8b82c49242a..ebb7529d3f733 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/IndexShardRoutingTableTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/IndexShardRoutingTableTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/MovePrimaryFirstTests.java b/server/src/test/java/org/opensearch/cluster/routing/MovePrimaryFirstTests.java
deleted file mode 100644
index aa2be1fb652cd..0000000000000
--- a/server/src/test/java/org/opensearch/cluster/routing/MovePrimaryFirstTests.java
+++ /dev/null
@@ -1,127 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-package org.opensearch.cluster.routing;
-
-import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope;
-import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
-import org.opensearch.cluster.ClusterStateListener;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.test.InternalTestCluster;
-import org.opensearch.test.OpenSearchIntegTestCase;
-
-import java.util.Iterator;
-import java.util.concurrent.CountDownLatch;
-
-import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
-
-@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
-@ThreadLeakScope(ThreadLeakScope.Scope.NONE)
-public class MovePrimaryFirstTests extends OpenSearchIntegTestCase {
-
-    protected String startDataOnlyNode(final String zone) {
-        final Settings settings = Settings.builder().put("node.attr.zone", zone).build();
-        return internalCluster().startDataOnlyNode(settings);
-    }
-
-    protected void createAndIndex(String index, int replicaCount, int shardCount) {
-        assertAcked(
-            prepareCreate(
-                index,
-                -1,
-                Settings.builder()
-                    .put("number_of_shards", shardCount)
-                    .put("number_of_replicas", replicaCount)
-                    .put("max_result_window", 20000)
-            )
-        );
-        int startDocCountId = 0;
-        for (int i = 0; i < 10; i++) {
-            index(index, "_doc", Integer.toString(startDocCountId), "foo", "bar" + startDocCountId);
-            ++startDocCountId;
-        }
-        flushAndRefresh(index);
-    }
-
-    /**
-     * Creates two nodes each in two zones and shuts down nodes in zone1 after
-     * relocating half the number of shards. Shards per node constraint ensures
-     * that exactly 50% of shards relocate to nodes in zone2 giving time to shut down
-     * nodes in zone1. Since primaries are relocated first as movePrimaryFirst is
-     * enabled, cluster should not become red and zone2 nodes have all the primaries
-     */
-    public void testClusterGreenAfterPartialRelocation() throws InterruptedException {
-        internalCluster().startMasterOnlyNodes(1);
-        final String z1 = "zone-1", z2 = "zone-2";
-        final int primaryShardCount = 6;
-        assertTrue("Primary shard count must be even for equal distribution across two nodes", primaryShardCount % 2 == 0);
-        final String z1n1 = startDataOnlyNode(z1);
-        ensureGreen();
-        createAndIndex("foo", 1, primaryShardCount);
-        ensureYellow();
-        // Start second node in same zone only after yellow cluster to ensure
-        // that one gets all primaries and other all secondaries
-        final String z1n2 = startDataOnlyNode(z1);
-        ensureGreen();
-
-        // Enable cluster level setting for moving primaries first and keep new
-        // zone nodes excluded to prevent any shard relocation
-        ClusterUpdateSettingsRequest settingsRequest = new ClusterUpdateSettingsRequest();
-        settingsRequest.persistentSettings(
-            Settings.builder().put("cluster.routing.allocation.move.primary_first", true).put("cluster.routing.allocation.exclude.zone", z2)
-        );
-        client().admin().cluster().updateSettings(settingsRequest).actionGet();
-
-        final String z2n1 = startDataOnlyNode(z2);
-        final String z2n2 = startDataOnlyNode(z2);
-
-        // Create cluster state listener to compute number of shards on new zone
-        // nodes before counting down the latch
-        final CountDownLatch primaryMoveLatch = new CountDownLatch(1);
-        final ClusterStateListener listener = event -> {
-            if (event.routingTableChanged()) {
-                final RoutingNodes routingNodes = event.state().getRoutingNodes();
-                int startedCount = 0;
-                for (Iterator<RoutingNode> it = routingNodes.iterator(); it.hasNext();) {
-                    RoutingNode routingNode = it.next();
-                    final String nodeName = routingNode.node().getName();
-                    if (nodeName.equals(z2n1) || nodeName.equals(z2n2)) {
-                        startedCount += routingNode.numberOfShardsWithState(ShardRoutingState.STARTED);
-                    }
-                }
-
-                // Count down the latch once all the primary shards have initialized on nodes in zone-2
-                if (startedCount == primaryShardCount) {
-                    primaryMoveLatch.countDown();
-                }
-            }
-        };
-        internalCluster().clusterService().addListener(listener);
-
-        // Exclude zone1 nodes for allocation and await latch count down
-        settingsRequest = new ClusterUpdateSettingsRequest();
-        settingsRequest.persistentSettings(
-            Settings.builder()
-                .put("cluster.routing.allocation.exclude.zone", z1)
-                // Total shards per node constraint is added to pause the relocation after primary shards
-                // have relocated to allow time for node shutdown and validate yellow cluster
-                .put("cluster.routing.allocation.total_shards_per_node", primaryShardCount / 2)
-        );
-        client().admin().cluster().updateSettings(settingsRequest);
-        primaryMoveLatch.await();
-
-        // Shutdown both nodes in zone 1 and ensure cluster does not become red
-        try {
-            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(z1n1));
-            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(z1n2));
-        } catch (Exception e) {}
-        // Due to shards per node constraint cluster cannot be green
-        // Since yellow suffices for this test, not removing shards constraint
-        ensureYellow();
-    }
-}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingAwarenessTests.java b/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingAwarenessTests.java
index d9675a548cc08..de787df8c08a9 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingAwarenessTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingAwarenessTests.java
@@ -8,13 +8,13 @@
 
 package org.opensearch.cluster.routing;
 
-import org.junit.After;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.junit.After;
 
-import static org.hamcrest.Matchers.equalTo;
 import static org.opensearch.cluster.routing.OperationRouting.IGNORE_AWARENESS_ATTRIBUTES;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.equalTo;
 
 public class OperationRoutingAwarenessTests extends OpenSearchIntegTestCase {
 
diff --git a/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingTests.java
index d42c3e80c60c9..4f3e50eebb9c6 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/OperationRoutingTests.java
@@ -36,6 +36,7 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
@@ -43,13 +44,15 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexModule;
 import org.opensearch.node.ResponseCollectorService;
 import org.opensearch.test.ClusterServiceUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -63,15 +66,15 @@
 import java.util.TreeMap;
 
 import static java.util.Collections.singletonMap;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_CREATION_DATE;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.object.HasToString.hasToString;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_CREATION_DATE;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
-import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 
 public class OperationRoutingTests extends OpenSearchTestCase {
     public void testGenerateShardId() {
@@ -759,6 +762,298 @@ public void testAdaptiveReplicaSelectionWithZoneAwarenessIgnored() throws Except
         terminate(threadPool);
     }
 
+    private ClusterState clusterStateForWeightedRouting(String[] indexNames, int numShards, int numReplicas) {
+        DiscoveryNode[] allNodes = setUpNodesForWeightedRouting();
+        ClusterState state = ClusterStateCreationUtils.state(allNodes[0], allNodes[6], allNodes);
+
+        Map<String, List<DiscoveryNode>> discoveryNodeMap = new HashMap<>();
+        List<DiscoveryNode> nodesZoneA = new ArrayList<>();
+        nodesZoneA.add(allNodes[0]);
+        nodesZoneA.add(allNodes[1]);
+
+        List<DiscoveryNode> nodesZoneB = new ArrayList<>();
+        nodesZoneB.add(allNodes[2]);
+        nodesZoneB.add(allNodes[3]);
+
+        List<DiscoveryNode> nodesZoneC = new ArrayList<>();
+        nodesZoneC.add(allNodes[4]);
+        nodesZoneC.add(allNodes[5]);
+        discoveryNodeMap.put("a", nodesZoneA);
+        discoveryNodeMap.put("b", nodesZoneB);
+        discoveryNodeMap.put("c", nodesZoneC);
+
+        // Updating cluster state with node, index and shard details
+        state = updateStatetoTestWeightedRouting(indexNames, numShards, numReplicas, state, discoveryNodeMap);
+
+        return state;
+
+    }
+
+    private ClusterState setWeightedRoutingWeights(ClusterState clusterState, Map<String, Double> weights) {
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+        return clusterState;
+    }
+
+    public void testWeightedOperationRouting() throws Exception {
+        final int numIndices = 2;
+        final int numShards = 3;
+        final int numReplicas = 2;
+        // setting up indices
+        final String[] indexNames = new String[numIndices];
+        for (int i = 0; i < numIndices; i++) {
+            indexNames[i] = "test" + i;
+        }
+        ClusterService clusterService = null;
+        TestThreadPool threadPool = null;
+        try {
+            ClusterState state = clusterStateForWeightedRouting(indexNames, numShards, numReplicas);
+
+            Settings setting = Settings.builder().put("cluster.routing.allocation.awareness.attributes", "zone").build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            OperationRouting opRouting = new OperationRouting(
+                setting,
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            );
+            assertTrue(opRouting.ignoreAwarenessAttributes());
+            Set<String> selectedNodes = new HashSet<>();
+            ResponseCollectorService collector = new ResponseCollectorService(clusterService);
+            Map<String, Long> outstandingRequests = new HashMap<>();
+
+            // Setting up weights for weighted round-robin in cluster state
+            Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+            state = setWeightedRoutingWeights(state, weights);
+
+            ClusterState.Builder builder = ClusterState.builder(state);
+            ClusterServiceUtils.setState(clusterService, builder);
+
+            // search shards call
+            GroupShardsIterator<ShardIterator> groupIterator = opRouting.searchShards(
+                state,
+                indexNames,
+                null,
+                null,
+                collector,
+                outstandingRequests
+
+            );
+
+            for (ShardIterator it : groupIterator) {
+                List<ShardRouting> shardRoutings = Collections.singletonList(it.nextOrNull());
+                for (ShardRouting shardRouting : shardRoutings) {
+                    selectedNodes.add(shardRouting.currentNodeId());
+                }
+            }
+            // tests no shards are assigned to nodes in zone c
+            for (String nodeID : selectedNodes) {
+                // No shards are assigned to nodes in zone c since its weight is 0
+                assertFalse(nodeID.contains("c"));
+            }
+
+            selectedNodes = new HashSet<>();
+            setting = Settings.builder().put("cluster.routing.allocation.awareness.attributes", "zone").build();
+
+            // Updating weighted round robin weights in cluster state
+            weights = Map.of("a", 1.0, "b", 0.0, "c", 1.0);
+            state = setWeightedRoutingWeights(state, weights);
+
+            builder = ClusterState.builder(state);
+            ClusterServiceUtils.setState(clusterService, builder);
+
+            opRouting = new OperationRouting(setting, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS));
+
+            // search shards call
+            groupIterator = opRouting.searchShards(state, indexNames, null, null, collector, outstandingRequests);
+
+            for (ShardIterator it : groupIterator) {
+                List<ShardRouting> shardRoutings = Collections.singletonList(it.nextOrNull());
+                for (ShardRouting shardRouting : shardRoutings) {
+                    selectedNodes.add(shardRouting.currentNodeId());
+                }
+            }
+            // tests that no shards are assigned to zone with weight zero
+            for (String nodeID : selectedNodes) {
+                // No shards are assigned to nodes in zone b since its weight is 0
+                assertFalse(nodeID.contains("b"));
+            }
+        } finally {
+            IOUtils.close(clusterService);
+            terminate(threadPool);
+        }
+    }
+
+    public void testWeightedOperationRoutingWeightUndefinedForOneZone() throws Exception {
+        final int numIndices = 2;
+        final int numShards = 3;
+        final int numReplicas = 2;
+        // setting up indices
+        final String[] indexNames = new String[numIndices];
+        for (int i = 0; i < numIndices; i++) {
+            indexNames[i] = "test" + i;
+        }
+
+        ClusterService clusterService = null;
+        TestThreadPool threadPool = null;
+        try {
+            ClusterState state = clusterStateForWeightedRouting(indexNames, numShards, numReplicas);
+
+            Settings setting = Settings.builder()
+                .put("cluster.routing.allocation.awareness.attributes", "zone")
+                .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+                .put("cluster.routing.weighted.fail_open", false)
+                .build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            OperationRouting opRouting = new OperationRouting(
+                setting,
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            );
+            assertTrue(opRouting.ignoreAwarenessAttributes());
+            Set<String> selectedNodes = new HashSet<>();
+            ResponseCollectorService collector = new ResponseCollectorService(clusterService);
+            Map<String, Long> outstandingRequests = new HashMap<>();
+
+            // Setting up weights for weighted round-robin in cluster state, weight for nodes in zone b is not set
+            Map<String, Double> weights = Map.of("a", 1.0, "c", 0.0);
+            state = setWeightedRoutingWeights(state, weights);
+            ClusterServiceUtils.setState(clusterService, ClusterState.builder(state));
+
+            // search shards call
+            GroupShardsIterator<ShardIterator> groupIterator = opRouting.searchShards(
+                state,
+                indexNames,
+                null,
+                null,
+                collector,
+                outstandingRequests
+
+            );
+
+            for (ShardIterator it : groupIterator) {
+                while (it.remaining() > 0) {
+                    ShardRouting shardRouting = it.nextOrNull();
+                    assertNotNull(shardRouting);
+                    selectedNodes.add(shardRouting.currentNodeId());
+                }
+            }
+            boolean weighAwayNodesInUndefinedZone = true;
+            // tests no shards are assigned to nodes in zone c
+            // tests shards are assigned to nodes in zone b
+            for (String nodeID : selectedNodes) {
+                // shard from nodes in zone c is not selected since its weight is 0
+                assertFalse(nodeID.contains("c"));
+                if (nodeID.contains("b")) {
+                    weighAwayNodesInUndefinedZone = false;
+                }
+            }
+            assertFalse(weighAwayNodesInUndefinedZone);
+
+            selectedNodes = new HashSet<>();
+
+            // Updating weighted round-robin weights in cluster state
+            weights = Map.of("a", 0.0, "b", 1.0);
+
+            state = setWeightedRoutingWeights(state, weights);
+            ClusterServiceUtils.setState(clusterService, ClusterState.builder(state));
+
+            opRouting = new OperationRouting(setting, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS));
+
+            // search shards call
+            groupIterator = opRouting.searchShards(state, indexNames, null, null, collector, outstandingRequests);
+
+            for (ShardIterator it : groupIterator) {
+                while (it.remaining() > 0) {
+                    ShardRouting shardRouting = it.nextOrNull();
+                    assertNotNull(shardRouting);
+                    selectedNodes.add(shardRouting.currentNodeId());
+                }
+            }
+
+            // tests that no shards are assigned to zone with weight zero
+            // tests shards are assigned to nodes in zone c
+            weighAwayNodesInUndefinedZone = true;
+            for (String nodeID : selectedNodes) {
+                // shard from nodes in zone a is not selected since its weight is 0
+                assertFalse(nodeID.contains("a"));
+                if (nodeID.contains("c")) {
+                    weighAwayNodesInUndefinedZone = false;
+                }
+            }
+            assertFalse(weighAwayNodesInUndefinedZone);
+        } finally {
+            IOUtils.close(clusterService);
+            terminate(threadPool);
+        }
+    }
+
+    public void testSearchableSnapshotPrimaryDefault() throws Exception {
+        final int numIndices = 1;
+        final int numShards = 2;
+        final int numReplicas = 2;
+        final String[] indexNames = new String[numIndices];
+        for (int i = 0; i < numIndices; i++) {
+            indexNames[i] = "test" + i;
+        }
+        // The first index is a searchable snapshot index
+        final String searchableSnapshotIndex = indexNames[0];
+        ClusterService clusterService = null;
+        ThreadPool threadPool = null;
+
+        try {
+            OperationRouting opRouting = new OperationRouting(
+                Settings.EMPTY,
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            );
+
+            ClusterState state = ClusterStateCreationUtils.stateWithAssignedPrimariesAndReplicas(indexNames, numShards, numReplicas);
+            threadPool = new TestThreadPool("testSearchableSnapshotPreference");
+            clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            // Update the index config within the cluster state to modify the index to a searchable snapshot index
+            IndexMetadata searchableSnapshotIndexMetadata = IndexMetadata.builder(searchableSnapshotIndex)
+                .settings(
+                    Settings.builder()
+                        .put(state.metadata().index(searchableSnapshotIndex).getSettings())
+                        .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                        .build()
+                )
+                .build();
+            Metadata.Builder metadataBuilder = Metadata.builder(state.metadata())
+                .put(searchableSnapshotIndexMetadata, false)
+                .generateClusterUuidIfNeeded();
+            state = ClusterState.builder(state).metadata(metadataBuilder.build()).build();
+
+            // Verify default preference is primary only
+            GroupShardsIterator<ShardIterator> groupIterator = opRouting.searchShards(state, indexNames, null, null);
+            assertThat("One group per index shard", groupIterator.size(), equalTo(numIndices * numShards));
+
+            for (ShardIterator shardIterator : groupIterator) {
+                assertThat("Only single shard will be returned with no preference", shardIterator.size(), equalTo(1));
+                assertTrue("Only primary should exist with no preference", shardIterator.nextOrNull().primary());
+            }
+
+            // Verify alternative preference can be applied to a searchable snapshot index
+            groupIterator = opRouting.searchShards(state, indexNames, null, "_replica");
+            assertThat("One group per index shard", groupIterator.size(), equalTo(numIndices * numShards));
+
+            for (ShardIterator shardIterator : groupIterator) {
+                assertThat("Replica shards will be returned", shardIterator.size(), equalTo(numReplicas));
+                assertFalse("Returned shard should be a replica", shardIterator.nextOrNull().primary());
+            }
+        } finally {
+            IOUtils.close(clusterService);
+            terminate(threadPool);
+        }
+    }
+
     private DiscoveryNode[] setupNodes() {
         // Sets up two data nodes in zone-a and one data node in zone-b
         List<String> zones = Arrays.asList("a", "a", "b");
@@ -774,14 +1069,40 @@ private DiscoveryNode[] setupNodes() {
             );
             allNodes[i++] = node;
         }
-        DiscoveryNode master = new DiscoveryNode(
-            "master",
+        DiscoveryNode clusterManager = new DiscoveryNode(
+            "cluster-manager",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            Version.CURRENT
+        );
+        allNodes[i] = clusterManager;
+        return allNodes;
+    }
+
+    private DiscoveryNode[] setUpNodesForWeightedRouting() {
+        List<String> zones = Arrays.asList("a", "a", "b", "b", "c", "c");
+        DiscoveryNode[] allNodes = new DiscoveryNode[7];
+        int i = 0;
+        for (String zone : zones) {
+            DiscoveryNode node = new DiscoveryNode(
+                "node_" + zone + "_" + i,
+                buildNewFakeTransportAddress(),
+                singletonMap("zone", zone),
+                Collections.singleton(DiscoveryNodeRole.DATA_ROLE),
+                Version.CURRENT
+            );
+            allNodes[i++] = node;
+        }
+
+        DiscoveryNode clusterManager = new DiscoveryNode(
+            "cluster-manager",
             buildNewFakeTransportAddress(),
             Collections.emptyMap(),
             Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
             Version.CURRENT
         );
-        allNodes[i] = master;
+        allNodes[i] = clusterManager;
         return allNodes;
     }
 
@@ -841,4 +1162,69 @@ private ClusterState updateStatetoTestARS(
         clusterState.routingTable(routingTableBuilder.build());
         return clusterState.build();
     }
+
+    private ClusterState updateStatetoTestWeightedRouting(
+        String[] indices,
+        int numberOfShards,
+        int numberOfReplicas,
+        ClusterState state,
+        Map<String, List<DiscoveryNode>> discoveryNodeMap
+    ) {
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
+        Metadata.Builder metadataBuilder = Metadata.builder();
+        ClusterState.Builder clusterState = ClusterState.builder(state);
+        List<DiscoveryNode> nodesZoneA = discoveryNodeMap.get("a");
+        List<DiscoveryNode> nodesZoneB = discoveryNodeMap.get("b");
+        List<DiscoveryNode> nodesZoneC = discoveryNodeMap.get("c");
+        for (String index : indices) {
+            IndexMetadata indexMetadata = IndexMetadata.builder(index)
+                .settings(
+                    Settings.builder()
+                        .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                        .put(SETTING_NUMBER_OF_SHARDS, numberOfShards)
+                        .put(SETTING_NUMBER_OF_REPLICAS, numberOfReplicas)
+                        .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+                )
+                .build();
+            metadataBuilder.put(indexMetadata, false).generateClusterUuidIfNeeded();
+            IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(indexMetadata.getIndex());
+            for (int i = 0; i < numberOfShards; i++) {
+                final ShardId shardId = new ShardId(index, "_na_", i);
+                IndexShardRoutingTable.Builder indexShardRoutingBuilder = new IndexShardRoutingTable.Builder(shardId);
+                // Assign all the primary shards on nodes in zone-a (node_a0 or node_a1)
+                indexShardRoutingBuilder.addShard(
+                    TestShardRouting.newShardRouting(
+                        index,
+                        i,
+                        nodesZoneA.get(randomInt(nodesZoneA.size() - 1)).getId(),
+                        null,
+                        true,
+                        ShardRoutingState.STARTED
+                    )
+                );
+                for (int replica = 0; replica < numberOfReplicas; replica++) {
+                    // Assign all the replicas on nodes in zone-b (node_b2)
+                    String nodeId = "";
+                    if (replica == 0) {
+                        nodeId = nodesZoneB.get(randomInt(nodesZoneB.size() - 1)).getId();
+                    } else {
+                        nodeId = nodesZoneC.get(randomInt(nodesZoneC.size() - 1)).getId();
+                    }
+                    indexShardRoutingBuilder.addShard(
+                        TestShardRouting.newShardRouting(index, i, nodeId, null, false, ShardRoutingState.STARTED)
+                    );
+                }
+                indexRoutingTableBuilder.addIndexShard(indexShardRoutingBuilder.build());
+            }
+            routingTableBuilder.add(indexRoutingTableBuilder.build());
+        }
+        // add weighted routing weights in metadata
+        Map<String, Double> weights = Map.of("a", 1.0, "b", 1.0, "c", 0.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState.metadata(metadataBuilder);
+        clusterState.routingTable(routingTableBuilder.build());
+        return clusterState.build();
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/PlainShardIteratorTests.java b/server/src/test/java/org/opensearch/cluster/routing/PlainShardIteratorTests.java
index 7548ee8f24e94..e9d5d377d0a70 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/PlainShardIteratorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/PlainShardIteratorTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/RecoverySourceTests.java b/server/src/test/java/org/opensearch/cluster/routing/RecoverySourceTests.java
index 45dafe08d926c..a5c006362a20c 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/RecoverySourceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/RecoverySourceTests.java
@@ -32,7 +32,12 @@
 
 package org.opensearch.cluster.routing;
 
+import org.opensearch.Version;
+import org.opensearch.common.UUIDs;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.repositories.IndexId;
+import org.opensearch.snapshots.Snapshot;
+import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -51,16 +56,53 @@ public void testSerialization() throws IOException {
         assertEquals(recoverySource, serializedRecoverySource);
     }
 
+    public void testSerializationSnapshotRecoverySource() throws IOException {
+        boolean isSearchableSnapshot = randomBoolean();
+        boolean isRemoteStoreShallowCopyEnabled = randomBoolean();
+        String sourceRemoteStoreRepo = "test-remote-repo";
+        RecoverySource.SnapshotRecoverySource recoverySource = new RecoverySource.SnapshotRecoverySource(
+            UUIDs.randomBase64UUID(),
+            new Snapshot("repo", new SnapshotId(randomAlphaOfLength(8), UUIDs.randomBase64UUID())),
+            Version.CURRENT,
+            new IndexId("some_index", UUIDs.randomBase64UUID(random())),
+            isSearchableSnapshot,
+            isRemoteStoreShallowCopyEnabled,
+            sourceRemoteStoreRepo
+        );
+        BytesStreamOutput out = new BytesStreamOutput();
+        recoverySource.writeTo(out);
+        RecoverySource serializedRecoverySource = RecoverySource.readFrom(out.bytes().streamInput());
+        assertEquals(recoverySource.getType(), serializedRecoverySource.getType());
+        assertEquals(recoverySource, serializedRecoverySource);
+        assertEquals(recoverySource.remoteStoreIndexShallowCopy(), isRemoteStoreShallowCopyEnabled);
+        assertEquals(recoverySource.isSearchableSnapshot(), isSearchableSnapshot);
+    }
+
     public void testRecoverySourceTypeOrder() {
         assertEquals(RecoverySource.Type.EMPTY_STORE.ordinal(), 0);
         assertEquals(RecoverySource.Type.EXISTING_STORE.ordinal(), 1);
         assertEquals(RecoverySource.Type.PEER.ordinal(), 2);
         assertEquals(RecoverySource.Type.SNAPSHOT.ordinal(), 3);
         assertEquals(RecoverySource.Type.LOCAL_SHARDS.ordinal(), 4);
+        assertEquals(RecoverySource.Type.REMOTE_STORE.ordinal(), 5);
         // check exhaustiveness
         for (RecoverySource.Type type : RecoverySource.Type.values()) {
             assertThat(type.ordinal(), greaterThanOrEqualTo(0));
-            assertThat(type.ordinal(), lessThanOrEqualTo(4));
+            assertThat(type.ordinal(), lessThanOrEqualTo(5));
         }
     }
+
+    public void testSerializationRemoteStoreRecoverySource() throws IOException {
+        RecoverySource recoverySource = new RecoverySource.RemoteStoreRecoverySource(
+            UUIDs.randomBase64UUID(),
+            Version.CURRENT,
+            new IndexId("some_index", UUIDs.randomBase64UUID(random()))
+        );
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        recoverySource.writeTo(out);
+        RecoverySource serializedRecoverySource = RecoverySource.readFrom(out.bytes().streamInput());
+        assertEquals(recoverySource.getType(), serializedRecoverySource.getType());
+        assertEquals(recoverySource, serializedRecoverySource);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/RoutingNodeTests.java b/server/src/test/java/org/opensearch/cluster/routing/RoutingNodeTests.java
index 5bd5b7d9f6a67..cc4f2e510cb31 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/RoutingNodeTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/RoutingNodeTests.java
@@ -35,9 +35,9 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.net.InetAddress;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/RoutingNodesTests.java b/server/src/test/java/org/opensearch/cluster/routing/RoutingNodesTests.java
index 3e9088d63cfb4..780d041c25d04 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/RoutingNodesTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/RoutingNodesTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing;
 
-import org.junit.Before;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
@@ -42,10 +41,13 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.settings.Settings;
+import org.junit.Before;
 
 import java.util.Iterator;
 import java.util.List;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
 
@@ -123,7 +125,7 @@ private IndexMetadata.Builder createIndexMetadata(String indexName) {
             .numberOfShards(this.numberOfShards);
     }
 
-    public void testInterleavedShardIterator() {
+    public void testInterleavedShardIteratorPrimaryFirst() {
         // Initialize all the shards for test index 1 and 2
         initPrimaries();
         startInitializingShards(TEST_INDEX_1);
@@ -146,7 +148,8 @@ public void testInterleavedShardIterator() {
         }
 
         // Get primary first shard iterator and assert primary shards are iterated over first
-        final Iterator<ShardRouting> iterator = this.clusterState.getRoutingNodes().nodeInterleavedShardIterator(true);
+        final Iterator<ShardRouting> iterator = this.clusterState.getRoutingNodes()
+            .nodeInterleavedShardIterator(ShardMovementStrategy.PRIMARY_FIRST);
         boolean iteratingPrimary = true;
         int shardCount = 0;
         while (iterator.hasNext()) {
@@ -154,10 +157,89 @@ public void testInterleavedShardIterator() {
             if (iteratingPrimary) {
                 iteratingPrimary = shard.primary();
             } else {
-                assert shard.primary() == false;
+                assertFalse(shard.primary());
             }
             shardCount++;
         }
-        assert shardCount == this.totalNumberOfShards;
+        assertEquals(shardCount, this.totalNumberOfShards);
+    }
+
+    public void testInterleavedShardIteratorNoPreference() {
+        // Initialize all the shards for test index 1 and 2
+        initPrimaries();
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_2);
+        startInitializingShards(TEST_INDEX_2);
+
+        final Iterator<ShardRouting> iterator = this.clusterState.getRoutingNodes()
+            .nodeInterleavedShardIterator(ShardMovementStrategy.NO_PREFERENCE);
+        int shardCount = 0;
+        while (iterator.hasNext()) {
+            final ShardRouting shard = iterator.next();
+            shardCount++;
+        }
+        assertEquals(shardCount, this.totalNumberOfShards);
+    }
+
+    public void testInterleavedShardIteratorReplicaFirst() {
+        // Initialize all the shards for test index 1 and 2
+        initPrimaries();
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_2);
+        startInitializingShards(TEST_INDEX_2);
+
+        // Get replica first shard iterator and assert replica shards are iterated over first
+        final Iterator<ShardRouting> iterator = this.clusterState.getRoutingNodes()
+            .nodeInterleavedShardIterator(ShardMovementStrategy.REPLICA_FIRST);
+        boolean iteratingReplica = true;
+        int shardCount = 0;
+        while (iterator.hasNext()) {
+            final ShardRouting shard = iterator.next();
+            if (iteratingReplica) {
+                iteratingReplica = shard.primary() == false;
+            } else {
+                assertTrue(shard.primary());
+            }
+            shardCount++;
+        }
+        assertEquals(shardCount, this.totalNumberOfShards);
+    }
+
+    public void testSwapPrimaryWithReplica() {
+        // Initialize all the shards for test index 1 and 2
+        initPrimaries();
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_1);
+        startInitializingShards(TEST_INDEX_2);
+        startInitializingShards(TEST_INDEX_2);
+
+        // Create primary shard count imbalance between two nodes
+        final RoutingNodes routingNodes = this.clusterState.getRoutingNodes();
+        final RoutingNode node0 = routingNodes.node("node0");
+        final RoutingNode node1 = routingNodes.node("node1");
+        final List<ShardRouting> shardRoutingList = node0.shardsWithState(TEST_INDEX_1, ShardRoutingState.STARTED);
+        final RoutingChangesObserver routingChangesObserver = Mockito.mock(RoutingChangesObserver.class);
+        int swaps = 0;
+
+        for (ShardRouting routing : shardRoutingList) {
+            if (routing.primary()) {
+                ShardRouting swap = node1.getByShardId(routing.shardId());
+                routingNodes.swapPrimaryWithReplica(logger, routing, swap, routingChangesObserver);
+                swaps++;
+            }
+        }
+        Mockito.verify(routingChangesObserver, Mockito.times(swaps)).replicaPromoted(Mockito.any());
+
+        final List<ShardRouting> shards = node1.shardsWithState(TEST_INDEX_1, ShardRoutingState.STARTED);
+        int shardCount = 0;
+        for (ShardRouting shard : shards) {
+            if (shard.primary()) {
+                shardCount++;
+            }
+        }
+
+        assertTrue(shardCount >= swaps);
     }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/RoutingTableGenerator.java b/server/src/test/java/org/opensearch/cluster/routing/RoutingTableGenerator.java
index e67fe47d0fb67..5d217d270a30e 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/RoutingTableGenerator.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/RoutingTableGenerator.java
@@ -32,10 +32,11 @@
 package org.opensearch.cluster.routing;
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
+
 import org.opensearch.OpenSearchException;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 
 import static org.opensearch.cluster.health.ClusterShardHealth.getInactivePrimaryHealth;
 
diff --git a/server/src/test/java/org/opensearch/cluster/routing/RoutingTableTests.java b/server/src/test/java/org/opensearch/cluster/routing/RoutingTableTests.java
index cc151b2cae086..8542ff53c6ff1 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/RoutingTableTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/RoutingTableTests.java
@@ -40,25 +40,36 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
+import org.opensearch.cluster.routing.RecoverySource.RemoteStoreRecoverySource;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.repositories.IndexId;
 import org.junit.Before;
 
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
+import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
+import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
+import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.opensearch.cluster.routing.ShardRoutingState.UNASSIGNED;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class RoutingTableTests extends OpenSearchAllocationTestCase {
 
@@ -225,6 +236,49 @@ public void testShardsMatchingPredicateCount() {
         assertThat(clusterState.routingTable().shardsMatchingPredicateCount(predicate), is(2));
     }
 
+    public void testAllShardsMatchingPredicate() {
+        MockAllocationService allocation = createAllocationService(Settings.EMPTY, new DelayedShardsMockGatewayAllocator());
+        Metadata metadata = Metadata.builder()
+            .put(IndexMetadata.builder("test1").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
+            .put(IndexMetadata.builder("test2").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
+            .build();
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(RoutingTable.builder().addAsNew(metadata.index("test1")).addAsNew(metadata.index("test2")).build())
+            .build();
+        clusterState = ClusterState.builder(clusterState)
+            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")))
+            .build();
+        clusterState = allocation.reroute(clusterState, "reroute");
+
+        Predicate<ShardRouting> predicate = s -> s.state() == ShardRoutingState.UNASSIGNED && s.unassignedInfo().isDelayed();
+        assertThat(clusterState.routingTable().allShardsSatisfyingPredicate(predicate).size(), is(0));
+
+        // starting primaries
+        clusterState = startInitializingShardsAndReroute(allocation, clusterState);
+        // starting replicas
+        clusterState = startInitializingShardsAndReroute(allocation, clusterState);
+        // remove node2 and reroute
+        clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder(clusterState.nodes()).remove("node2")).build();
+        // make sure both replicas are marked as delayed (i.e. not reallocated)
+        clusterState = allocation.disassociateDeadNodes(clusterState, true, "reroute");
+        assertThat(clusterState.routingTable().allShardsSatisfyingPredicate(predicate).size(), is(2));
+
+        // Verifies true against all shards on the node (active/inactive)
+        assertThat(clusterState.routingTable().allShardsSatisfyingPredicate(shard -> true).size(), is(4));
+        // Verifies false against all shards on the node (active/inactive)
+        assertThat(clusterState.routingTable().allShardsSatisfyingPredicate(shard -> false).size(), is(0));
+        // Verifies against all primary shards on the node
+        assertThat(clusterState.routingTable().allShardsSatisfyingPredicate(ShardRouting::primary).size(), is(2));
+        // Verifies a predicate which tests for inactive replicas
+        assertThat(
+            clusterState.routingTable()
+                .allShardsSatisfyingPredicate(shardRouting -> !shardRouting.primary() && !shardRouting.active())
+                .size(),
+            is(2)
+        );
+    }
+
     public void testActivePrimaryShardsGrouped() {
         assertThat(this.emptyRoutingTable.activePrimaryShardsGrouped(new String[0], true).size(), is(0));
         assertThat(this.emptyRoutingTable.activePrimaryShardsGrouped(new String[0], false).size(), is(0));
@@ -492,6 +546,130 @@ public void testAddAsRecovery() {
         }
     }
 
+    private Map<ShardId, IndexShardRoutingTable> getIndexShardRoutingTableMap(Index index, boolean allUnassigned, int numberOfReplicas) {
+        Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap = new HashMap<>();
+        List<ShardRoutingState> activeInitializingStates = List.of(INITIALIZING, STARTED, RELOCATING);
+        for (int i = 0; i < this.numberOfShards; i++) {
+            IndexShardRoutingTable indexShardRoutingTable = mock(IndexShardRoutingTable.class);
+            ShardRouting primaryShardRouting = mock(ShardRouting.class);
+            Boolean primaryUnassigned = allUnassigned || randomBoolean();
+            when(primaryShardRouting.unassigned()).thenReturn(primaryUnassigned);
+            if (primaryUnassigned) {
+                when(primaryShardRouting.state()).thenReturn(UNASSIGNED);
+            } else {
+                when(primaryShardRouting.state()).thenReturn(
+                    activeInitializingStates.get(randomIntBetween(0, activeInitializingStates.size() - 1))
+                );
+            }
+            when(indexShardRoutingTable.primaryShard()).thenReturn(primaryShardRouting);
+            List<ShardRouting> replicaShards = new ArrayList<>();
+            for (int j = 0; j < numberOfReplicas; j++) {
+                ShardRouting replicaShardRouting = mock(ShardRouting.class);
+                Boolean replicaUnassigned = allUnassigned || randomBoolean();
+                when(replicaShardRouting.unassigned()).thenReturn(replicaUnassigned);
+                if (replicaUnassigned) {
+                    when(replicaShardRouting.state()).thenReturn(UNASSIGNED);
+                } else {
+                    when(replicaShardRouting.state()).thenReturn(
+                        activeInitializingStates.get(randomIntBetween(0, activeInitializingStates.size() - 1))
+                    );
+                }
+                replicaShards.add(replicaShardRouting);
+            }
+            when(indexShardRoutingTable.replicaShards()).thenReturn(replicaShards);
+            indexShardRoutingTableMap.put(new ShardId(index, i), indexShardRoutingTable);
+        }
+        return indexShardRoutingTableMap;
+    }
+
+    public void testAddAsRemoteStoreRestoreAllUnassigned() {
+        int numberOfReplicas = randomIntBetween(0, 5);
+        final IndexMetadata indexMetadata = createIndexMetadata(TEST_INDEX_1).state(IndexMetadata.State.OPEN)
+            .numberOfReplicas(numberOfReplicas)
+            .build();
+        final RemoteStoreRecoverySource remoteStoreRecoverySource = new RemoteStoreRecoverySource(
+            "restore_uuid",
+            Version.CURRENT,
+            new IndexId(TEST_INDEX_1, "1")
+        );
+        final RoutingTable routingTable = new RoutingTable.Builder().addAsRemoteStoreRestore(
+            indexMetadata,
+            remoteStoreRecoverySource,
+            getIndexShardRoutingTableMap(indexMetadata.getIndex(), true, numberOfReplicas),
+            false
+        ).build();
+        assertTrue(routingTable.hasIndex(TEST_INDEX_1));
+        int numberOfShards = this.numberOfShards * (numberOfReplicas + 1);
+        assertEquals(numberOfShards, routingTable.allShards(TEST_INDEX_1).size());
+        assertEquals(numberOfShards, routingTable.index(TEST_INDEX_1).shardsWithState(UNASSIGNED).size());
+    }
+
+    public void testAddAsRemoteStoreRestoreWithActiveShards() {
+        int numberOfReplicas = randomIntBetween(0, 5);
+        final IndexMetadata indexMetadata = createIndexMetadata(TEST_INDEX_1).state(IndexMetadata.State.OPEN)
+            .numberOfReplicas(numberOfReplicas)
+            .build();
+        final RemoteStoreRecoverySource remoteStoreRecoverySource = new RemoteStoreRecoverySource(
+            "restore_uuid",
+            Version.CURRENT,
+            new IndexId(TEST_INDEX_1, "1")
+        );
+        Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap = getIndexShardRoutingTableMap(
+            indexMetadata.getIndex(),
+            false,
+            numberOfReplicas
+        );
+        final RoutingTable routingTable = new RoutingTable.Builder().addAsRemoteStoreRestore(
+            indexMetadata,
+            remoteStoreRecoverySource,
+            indexShardRoutingTableMap,
+            false
+        ).build();
+        assertTrue(routingTable.hasIndex(TEST_INDEX_1));
+        int numberOfShards = this.numberOfShards * (numberOfReplicas + 1);
+        assertEquals(numberOfShards, routingTable.allShards(TEST_INDEX_1).size());
+        int unassignedShards = 0;
+        for (IndexShardRoutingTable indexShardRoutingTable : indexShardRoutingTableMap.values()) {
+            if (indexShardRoutingTable.primaryShard().unassigned()) {
+                unassignedShards += indexShardRoutingTable.replicaShards().size() + 1;
+            } else {
+                for (ShardRouting replicaShardRouting : indexShardRoutingTable.replicaShards()) {
+                    if (replicaShardRouting.unassigned()) {
+                        unassignedShards += 1;
+                    }
+                }
+            }
+        }
+        assertEquals(unassignedShards, routingTable.index(TEST_INDEX_1).shardsWithState(UNASSIGNED).size());
+    }
+
+    public void testAddAsRemoteStoreRestoreShardMismatch() {
+        int numberOfReplicas = randomIntBetween(0, 5);
+        final IndexMetadata indexMetadata = createIndexMetadata(TEST_INDEX_1).state(IndexMetadata.State.OPEN)
+            .numberOfReplicas(numberOfReplicas)
+            .build();
+        final RemoteStoreRecoverySource remoteStoreRecoverySource = new RemoteStoreRecoverySource(
+            "restore_uuid",
+            Version.CURRENT,
+            new IndexId(TEST_INDEX_1, "1")
+        );
+        Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap = getIndexShardRoutingTableMap(
+            indexMetadata.getIndex(),
+            true,
+            numberOfReplicas
+        );
+        indexShardRoutingTableMap.remove(indexShardRoutingTableMap.keySet().iterator().next());
+        assertThrows(
+            IllegalStateException.class,
+            () -> new RoutingTable.Builder().addAsRemoteStoreRestore(
+                indexMetadata,
+                remoteStoreRecoverySource,
+                indexShardRoutingTableMap,
+                false
+            ).build()
+        );
+    }
+
     /** reverse engineer the in sync aid based on the given indexRoutingTable **/
     public static IndexMetadata updateActiveAllocations(IndexRoutingTable indexRoutingTable, IndexMetadata indexMetadata) {
         IndexMetadata.Builder imdBuilder = IndexMetadata.builder(indexMetadata);
diff --git a/server/src/test/java/org/opensearch/cluster/routing/ShardMovementStrategyTests.java b/server/src/test/java/org/opensearch/cluster/routing/ShardMovementStrategyTests.java
new file mode 100644
index 0000000000000..7483e69fb0b0e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/ShardMovementStrategyTests.java
@@ -0,0 +1,171 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope;
+
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.cluster.ClusterStateListener;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Iterator;
+import java.util.concurrent.CountDownLatch;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+@ThreadLeakScope(ThreadLeakScope.Scope.NONE)
+public class ShardMovementStrategyTests extends OpenSearchIntegTestCase {
+
+    protected String startDataOnlyNode(final String zone) {
+        final Settings settings = Settings.builder().put("node.attr.zone", zone).build();
+        return internalCluster().startDataOnlyNode(settings);
+    }
+
+    protected void createAndIndex(String index, int replicaCount, int shardCount) {
+        assertAcked(
+            prepareCreate(
+                index,
+                -1,
+                Settings.builder()
+                    .put("number_of_shards", shardCount)
+                    .put("number_of_replicas", replicaCount)
+                    .put("max_result_window", 20000)
+            )
+        );
+        int startDocCountId = 0;
+        for (int i = 0; i < 10; i++) {
+            index(index, "_doc", Integer.toString(startDocCountId), "foo", "bar" + startDocCountId);
+            ++startDocCountId;
+        }
+        flushAndRefresh(index);
+    }
+
+    private static Settings.Builder getSettings(ShardMovementStrategy shardMovementStrategy, boolean movePrimaryFirst) {
+        return Settings.builder()
+            .put("cluster.routing.allocation.shard_movement_strategy", shardMovementStrategy)
+            .put("cluster.routing.allocation.move.primary_first", movePrimaryFirst);
+    }
+
+    public void testClusterRelocationPrimaryFirstShardMovementMovePrimarySettingEnabled() throws InterruptedException {
+        testClusterGreenAfterPartialRelocation(ShardMovementStrategy.PRIMARY_FIRST, true);
+    }
+
+    public void testClusterRelocationPrimaryFirstShardMovementMovePrimarySettingDisabled() throws InterruptedException {
+        testClusterGreenAfterPartialRelocation(ShardMovementStrategy.PRIMARY_FIRST, false);
+    }
+
+    public void testClusterRelocationReplicaFirstShardMovementPrimaryFirstEnabled() throws InterruptedException {
+        testClusterGreenAfterPartialRelocation(ShardMovementStrategy.REPLICA_FIRST, true);
+    }
+
+    public void testClusterRelocationReplicaFirstShardMovementPrimaryFirstDisabled() throws InterruptedException {
+        testClusterGreenAfterPartialRelocation(ShardMovementStrategy.REPLICA_FIRST, false);
+    }
+
+    public void testClusterRelocationNoPreferenceShardMovementPrimaryFirstEnabled() throws InterruptedException {
+        testClusterGreenAfterPartialRelocation(ShardMovementStrategy.NO_PREFERENCE, true);
+    }
+
+    private boolean shouldMovePrimaryShardsFirst(ShardMovementStrategy shardMovementStrategy, boolean movePrimaryFirst) {
+        if (shardMovementStrategy == ShardMovementStrategy.NO_PREFERENCE && movePrimaryFirst) {
+            return true;
+        }
+        return shardMovementStrategy == ShardMovementStrategy.PRIMARY_FIRST;
+    }
+
+    /**
+     * Creates two nodes each in two zones and shuts down nodes in zone1 after
+     * relocating half the number of shards. Shards per node constraint ensures
+     * that exactly 50% of shards relocate to nodes in zone2 giving time to shut down
+     * nodes in zone1. Depending on the shard movement strategy, we check whether the
+     * primary or replica shards are moved first, and zone2 nodes have all the shards
+     */
+    private void testClusterGreenAfterPartialRelocation(ShardMovementStrategy shardMovementStrategy, boolean movePrimaryFirst)
+        throws InterruptedException {
+        internalCluster().startClusterManagerOnlyNodes(1);
+        final String z1 = "zone-1", z2 = "zone-2";
+        final int primaryShardCount = 6;
+        assertTrue("Primary shard count must be even for equal distribution across two nodes", primaryShardCount % 2 == 0);
+        final String z1n1 = startDataOnlyNode(z1);
+        ensureGreen();
+        createAndIndex("foo", 1, primaryShardCount);
+        ensureYellow();
+        // Start second node in same zone only after yellow cluster to ensure
+        // that one gets all primaries and other all secondaries
+        final String z1n2 = startDataOnlyNode(z1);
+        ensureGreen();
+
+        // Enable cluster level setting for moving primaries first and keep new
+        // zone nodes excluded to prevent any shard relocation
+        ClusterUpdateSettingsRequest settingsRequest = new ClusterUpdateSettingsRequest();
+        settingsRequest.persistentSettings(
+            getSettings(shardMovementStrategy, movePrimaryFirst).put("cluster.routing.allocation.exclude.zone", z2)
+        );
+        client().admin().cluster().updateSettings(settingsRequest).actionGet();
+
+        final String z2n1 = startDataOnlyNode(z2);
+        final String z2n2 = startDataOnlyNode(z2);
+
+        // Create cluster state listener to compute number of shards on new zone
+        // nodes before counting down the latch
+        final CountDownLatch shardMoveLatch = new CountDownLatch(1);
+        final ClusterStateListener listener = event -> {
+            if (event.routingTableChanged()) {
+                final RoutingNodes routingNodes = event.state().getRoutingNodes();
+                int startedCount = 0;
+                for (Iterator<RoutingNode> it = routingNodes.iterator(); it.hasNext();) {
+                    RoutingNode routingNode = it.next();
+                    final String nodeName = routingNode.node().getName();
+                    if (nodeName.equals(z2n1) || nodeName.equals(z2n2)) {
+                        int count = 0;
+                        for (ShardRouting shardEntry : routingNode) {
+                            // If shard movement strategy is primary first, asserting that primary shards are moved first; else assert
+                            // shards are replicas
+                            if ((shardEntry.primary() == shouldMovePrimaryShardsFirst(shardMovementStrategy, movePrimaryFirst))
+                                && shardEntry.state() == ShardRoutingState.STARTED) {
+                                count++;
+                            }
+                        }
+                        startedCount += count;
+                    }
+                }
+
+                // Count down the latch once all the shards have initialized on nodes in zone-2
+                if (startedCount == primaryShardCount) {
+                    shardMoveLatch.countDown();
+                }
+            }
+        };
+        internalCluster().clusterService().addListener(listener);
+
+        // Exclude zone1 nodes for allocation and await latch count down
+        settingsRequest = new ClusterUpdateSettingsRequest();
+        settingsRequest.persistentSettings(
+            Settings.builder()
+                .put("cluster.routing.allocation.exclude.zone", z1)
+                // Total shards per node constraint is added to pause the relocation after shards
+                // have relocated to allow time for node shutdown and validate yellow cluster
+                .put("cluster.routing.allocation.total_shards_per_node", primaryShardCount / 2)
+        );
+        client().admin().cluster().updateSettings(settingsRequest);
+        shardMoveLatch.await();
+
+        // Shutdown both nodes in zone 1 and ensure cluster does not become red
+        try {
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(z1n1));
+            internalCluster().stopRandomNode(InternalTestCluster.nameFilter(z1n2));
+        } catch (Exception e) {}
+        // Due to shards per node constraint cluster cannot be green
+        // Since yellow suffices for this test, not removing shards constraint
+        ensureYellow();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/ShardRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/ShardRoutingTests.java
index 1dd27cb706c64..63c7b5f70f85c 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/ShardRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/ShardRoutingTests.java
@@ -34,12 +34,12 @@
 
 import org.opensearch.Version;
 import org.opensearch.common.UUIDs;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.repositories.IndexId;
-import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
+import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -301,6 +301,18 @@ public void testEqualsIgnoringVersion() {
         }
     }
 
+    public void testSwapPrimaryWithReplica() {
+        final ShardRouting unassignedShard0 = TestShardRouting.newShardRouting("test", 0, null, false, ShardRoutingState.UNASSIGNED);
+        assertThrows(AssertionError.class, unassignedShard0::moveActivePrimaryToReplica);
+
+        final ShardRouting activeShard0 = TestShardRouting.newShardRouting("test", 0, "node-1", false, ShardRoutingState.STARTED);
+        assertThrows(IllegalShardRoutingStateException.class, activeShard0::moveActivePrimaryToReplica);
+
+        final ShardRouting activeShard1 = TestShardRouting.newShardRouting("test", 0, "node-1", true, ShardRoutingState.STARTED);
+        final ShardRouting activeReplicaShard1 = activeShard1.moveActivePrimaryToReplica();
+        assertFalse(activeReplicaShard1.primary());
+    }
+
     public void testExpectedSize() throws IOException {
         final int iters = randomIntBetween(10, 100);
         for (int i = 0; i < iters; i++) {
diff --git a/server/src/test/java/org/opensearch/cluster/routing/UnassignedInfoTests.java b/server/src/test/java/org/opensearch/cluster/routing/UnassignedInfoTests.java
index 6071d2cbc214d..8800394431a42 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/UnassignedInfoTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/UnassignedInfoTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.cluster.routing;
 
-import com.carrotsearch.hppc.IntHashSet;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -46,11 +46,11 @@
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.FailedShard;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
+import org.opensearch.core.index.Index;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
@@ -58,6 +58,7 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
@@ -202,7 +203,7 @@ public void testNewIndexRestored() {
                             Version.CURRENT,
                             new IndexId("test", UUIDs.randomBase64UUID(random()))
                         ),
-                        new IntHashSet()
+                        new HashSet<>()
                     )
                     .build()
             )
diff --git a/server/src/test/java/org/opensearch/cluster/routing/WeightedRoundRobinTests.java b/server/src/test/java/org/opensearch/cluster/routing/WeightedRoundRobinTests.java
new file mode 100644
index 0000000000000..5f62d30486e86
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/WeightedRoundRobinTests.java
@@ -0,0 +1,151 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class WeightedRoundRobinTests extends OpenSearchTestCase {
+
+    public void testWeightedRoundRobinOrder() {
+        // weights set as A:4, B:3, C:2
+        List<WeightedRoundRobin.Entity<String>> entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(4, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(3, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(2, "C"));
+        WeightedRoundRobin<String> weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        List<WeightedRoundRobin.Entity<String>> orderedEntities = weightedRoundRobin.orderEntities();
+        List<String> expectedOrdering = Arrays.asList("A", "A", "B", "A", "B", "C", "A", "B", "C");
+        List<String> actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set as A:1, B:1, C:0
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(1, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(1, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList("A", "B");
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set as A:0, B:0, C:0
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(0, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList();
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set as A:-1, B:0, C:1
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(-1, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(1, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList("C");
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set as A:-1, B:3, C:0, D:10
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(-1, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(3, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "C"));
+        entity.add(new WeightedRoundRobin.Entity<>(10, "D"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList("B", "D", "B", "D", "B", "D", "D", "D", "D", "D", "D", "D", "D");
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set as A:-1, B:3, C:0, D:10000
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(-1, "A"));
+        entity.add(new WeightedRoundRobin.Entity<>(3, "B"));
+        entity.add(new WeightedRoundRobin.Entity<>(0, "C"));
+        entity.add(new WeightedRoundRobin.Entity<>(10000, "D"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        assertEquals(10003, orderedEntities.size());
+        // Count of D's
+        int countD = 0;
+        // Count of B's
+        int countB = 0;
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            if (en.getTarget().equals("D")) {
+                countD++;
+            } else if (en.getTarget().equals("B")) {
+                countB++;
+            }
+        }
+        assertEquals(3, countB);
+        assertEquals(10000, countD);
+
+        // weights set C:0
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(0, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList();
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set C:1
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(1, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList("C");
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+
+        // weights set C:2
+        entity = new ArrayList<WeightedRoundRobin.Entity<String>>();
+        entity.add(new WeightedRoundRobin.Entity<>(2, "C"));
+        weightedRoundRobin = new WeightedRoundRobin<String>(entity);
+        orderedEntities = weightedRoundRobin.orderEntities();
+        expectedOrdering = Arrays.asList("C", "C");
+        actualOrdering = new ArrayList<>();
+        for (WeightedRoundRobin.Entity<String> en : orderedEntities) {
+            actualOrdering.add(en.getTarget());
+        }
+        assertEquals(expectedOrdering, actualOrdering);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/WeightedRoutingServiceTests.java b/server/src/test/java/org/opensearch/cluster/routing/WeightedRoutingServiceTests.java
new file mode 100644
index 0000000000000..5c0bdc8547f8b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/WeightedRoutingServiceTests.java
@@ -0,0 +1,470 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.Version;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingResponse;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterAddWeightedRoutingAction;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequestBuilder;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
+import org.opensearch.cluster.decommission.DecommissionAttribute;
+import org.opensearch.cluster.decommission.DecommissionAttributeMetadata;
+import org.opensearch.cluster.decommission.DecommissionStatus;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.metadata.WeightedRoutingMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.notNullValue;
+
+public class WeightedRoutingServiceTests extends OpenSearchTestCase {
+    private ThreadPool threadPool;
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private WeightedRoutingService weightedRoutingService;
+    private ClusterSettings clusterSettings;
+    NodeClient client;
+
+    final private static Set<DiscoveryNodeRole> CLUSTER_MANAGER_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE))
+    );
+
+    final private static Set<DiscoveryNodeRole> DATA_ROLE = Collections.unmodifiableSet(
+        new HashSet<>(Collections.singletonList(DiscoveryNodeRole.DATA_ROLE))
+    );
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("test", Settings.EMPTY);
+        clusterService = ClusterServiceUtils.createClusterService(threadPool);
+    }
+
+    @Before
+    public void setUpService() {
+        ClusterState clusterState = ClusterState.builder(new ClusterName("test")).build();
+        clusterState = addClusterManagerNodes(clusterState);
+        clusterState = addDataNodes(clusterState);
+        clusterState = setLocalNode(clusterState, "nodeA1");
+
+        ClusterState.Builder builder = ClusterState.builder(clusterState);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        final MockTransport transport = new MockTransport();
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundTransportAddress -> clusterService.state().nodes().get("nodes1"),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+        Settings.Builder settingsBuilder = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone");
+
+        clusterSettings = new ClusterSettings(settingsBuilder.build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        this.weightedRoutingService = new WeightedRoutingService(clusterService, threadPool, settingsBuilder.build(), clusterSettings);
+        client = new NodeClient(Settings.EMPTY, threadPool);
+    }
+
+    @After
+    public void shutdown() {
+        clusterService.stop();
+        threadPool.shutdown();
+    }
+
+    private ClusterState addDataNodes(ClusterState clusterState) {
+        clusterState = addDataNodeForAZone(clusterState, "zone_A", "nodeA1", "nodeA2", "nodeA3");
+        clusterState = addDataNodeForAZone(clusterState, "zone_B", "nodeB1", "nodeB2", "nodeB3");
+        clusterState = addDataNodeForAZone(clusterState, "zone_C", "nodeC1", "nodeC2", "nodeC3");
+        return clusterState;
+    }
+
+    private ClusterState addClusterManagerNodes(ClusterState clusterState) {
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_A", "nodeMA");
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_B", "nodeMB");
+        clusterState = addClusterManagerNodeForAZone(clusterState, "zone_C", "nodeMC");
+        return clusterState;
+    }
+
+    private ClusterState addDataNodeForAZone(ClusterState clusterState, String zone, String... nodeIds) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds)
+            .forEach(
+                nodeId -> nodeBuilder.add(
+                    new DiscoveryNode(
+                        nodeId,
+                        buildNewFakeTransportAddress(),
+                        Collections.singletonMap("zone", zone),
+                        DATA_ROLE,
+                        Version.CURRENT
+                    )
+                )
+            );
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState addClusterManagerNodeForAZone(ClusterState clusterState, String zone, String... nodeIds) {
+
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        List.of(nodeIds)
+            .forEach(
+                nodeId -> nodeBuilder.add(
+                    new DiscoveryNode(
+                        nodeId,
+                        buildNewFakeTransportAddress(),
+                        Collections.singletonMap("zone", zone),
+                        CLUSTER_MANAGER_ROLE,
+                        Version.CURRENT
+                    )
+                )
+            );
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setLocalNode(ClusterState clusterState, String nodeId) {
+        DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
+        nodeBuilder.localNodeId(nodeId);
+        nodeBuilder.clusterManagerNodeId(nodeId);
+        clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setWeightedRoutingWeights(ClusterState clusterState, Map<String, Double> weights) {
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        WeightedRoutingMetadata weightedRoutingMetadata = new WeightedRoutingMetadata(weightedRouting, 0);
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.putCustom(WeightedRoutingMetadata.TYPE, weightedRoutingMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+        return clusterState;
+    }
+
+    private ClusterState setDecommissionAttribute(ClusterState clusterState, DecommissionStatus status) {
+        DecommissionAttribute decommissionAttribute = new DecommissionAttribute("zone", "zone_A");
+        DecommissionAttributeMetadata decommissionAttributeMetadata = new DecommissionAttributeMetadata(
+            decommissionAttribute,
+            status,
+            randomAlphaOfLength(10)
+        );
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.metadata());
+        metadataBuilder.decommissionAttributeMetadata(decommissionAttributeMetadata);
+        clusterState = ClusterState.builder(clusterState).metadata(metadataBuilder).build();
+        return clusterState;
+    }
+
+    public void testRegisterWeightedRoutingMetadataWithChangedWeights() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 1.0);
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        WeightedRouting updatedWeightedRouting = new WeightedRouting("zone", Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 0.0));
+        request.setWeightedRouting(updatedWeightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                assertTrue(clusterStateUpdateResponse.isAcknowledged());
+                assertEquals(updatedWeightedRouting, clusterService.state().metadata().weightedRoutingMetadata().getWeightedRouting());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("request should not fail");
+            }
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testRegisterWeightedRoutingMetadataWithSameWeights() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 1.0);
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        WeightedRouting updatedWeightedRouting = new WeightedRouting("zone", weights);
+        request.setWeightedRouting(updatedWeightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                assertTrue(clusterStateUpdateResponse.isAcknowledged());
+                assertEquals(updatedWeightedRouting, clusterService.state().metadata().weightedRoutingMetadata().getWeightedRouting());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("request should not fail");
+            }
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testDeleteWeightedRoutingMetadata() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 1.0);
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterDeleteWeightedRoutingRequest clusterDeleteWeightedRoutingRequest = new ClusterDeleteWeightedRoutingRequest("zone");
+        clusterDeleteWeightedRoutingRequest.setVersion(0);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<ClusterDeleteWeightedRoutingResponse> listener = new ActionListener<ClusterDeleteWeightedRoutingResponse>() {
+            @Override
+            public void onResponse(ClusterDeleteWeightedRoutingResponse clusterDeleteWeightedRoutingResponse) {
+                assertTrue(clusterDeleteWeightedRoutingResponse.isAcknowledged());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("on failure shouldn't have been called");
+            }
+        };
+        weightedRoutingService.deleteWeightedRoutingMetadata(clusterDeleteWeightedRoutingRequest, listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testVerifyAwarenessAttribute_InvalidAttributeName() {
+        assertThrows(
+            "invalid awareness attribute %s requested for updating weighted routing",
+            ActionRequestValidationException.class,
+            () -> weightedRoutingService.verifyAwarenessAttribute("zone2")
+        );
+    }
+
+    public void testVerifyAwarenessAttribute_ValidAttributeName() {
+        try {
+            weightedRoutingService.verifyAwarenessAttribute("zone");
+        } catch (Exception e) {
+            fail("verify awareness attribute should not fail");
+        }
+    }
+
+    public void testAddWeightedRoutingFailsWhenWeightsNotSetForAllDiscoveredZones() throws InterruptedException {
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_C", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        request.setWeightedRouting(weightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionReference.set(e);
+                countDownLatch.countDown();
+            }
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        MatcherAssert.assertThat("Expected onFailure to be called", exceptionReference.get(), notNullValue());
+        MatcherAssert.assertThat(exceptionReference.get(), instanceOf(UnsupportedWeightedRoutingStateException.class));
+        MatcherAssert.assertThat(
+            exceptionReference.get().getMessage(),
+            containsString("weight for [zone_B] is not set and it is part of forced awareness value or a routing node has this attribute.")
+        );
+    }
+
+    public void testAddWeightedRoutingFailsWhenWeightsForMoreThanHalfIsZero() throws InterruptedException {
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        Map<String, Double> weights = Map.of("zone_A", 0.0, "zone_B", 0.0, "zone_C", 1.0, "zone_D", 1.0, "zone_E", 1.0, "zone_F", 1.0);
+        WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+        request.setWeightedRouting(weightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionReference.set(e);
+                countDownLatch.countDown();
+            }
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        MatcherAssert.assertThat("Expected onFailure to be called", exceptionReference.get(), notNullValue());
+        MatcherAssert.assertThat(exceptionReference.get(), instanceOf(ActionRequestValidationException.class));
+        MatcherAssert.assertThat(
+            exceptionReference.get().getMessage(),
+            containsString("Maximum expected number of routing weights having zero weight is [1]")
+        );
+    }
+
+    public void testAddWeightedRoutingFailsWhenDecommissionOngoing() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 1.0);
+        DecommissionStatus status = randomFrom(DecommissionStatus.INIT, DecommissionStatus.IN_PROGRESS, DecommissionStatus.SUCCESSFUL);
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        state = setDecommissionAttribute(state, status);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        WeightedRouting updatedWeightedRouting = new WeightedRouting("zone", weights);
+        request.setWeightedRouting(updatedWeightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionReference.set(e);
+                countDownLatch.countDown();
+            }
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        MatcherAssert.assertThat("Expected onFailure to be called", exceptionReference.get(), notNullValue());
+        MatcherAssert.assertThat(exceptionReference.get(), instanceOf(UnsupportedWeightedRoutingStateException.class));
+        MatcherAssert.assertThat(
+            exceptionReference.get().getMessage(),
+            containsString("weight for [zone_A] must be set to [0.0] as it is under decommission action")
+        );
+    }
+
+    public void testAddWeightedRoutingPassesWhenDecommissionFailed() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 1.0, "zone_B", 1.0, "zone_C", 1.0);
+        DecommissionStatus status = DecommissionStatus.FAILED;
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        state = setDecommissionAttribute(state, status);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        WeightedRouting updatedWeightedRouting = new WeightedRouting("zone", weights);
+        request.setWeightedRouting(updatedWeightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> exceptionReference = new AtomicReference<>();
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                assertTrue(clusterStateUpdateResponse.isAcknowledged());
+                assertEquals(updatedWeightedRouting, clusterService.state().metadata().weightedRoutingMetadata().getWeightedRouting());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+    }
+
+    public void testAddWeightedRoutingPassesWhenWeightOfDecommissionedAttributeStillZero() throws InterruptedException {
+        Map<String, Double> weights = Map.of("zone_A", 0.0, "zone_B", 1.0, "zone_C", 1.0);
+        DecommissionStatus status = DecommissionStatus.SUCCESSFUL;
+        ClusterState state = clusterService.state();
+        state = setWeightedRoutingWeights(state, weights);
+        state = setDecommissionAttribute(state, status);
+        ClusterState.Builder builder = ClusterState.builder(state);
+        ClusterServiceUtils.setState(clusterService, builder);
+
+        ClusterPutWeightedRoutingRequestBuilder request = new ClusterPutWeightedRoutingRequestBuilder(
+            client,
+            ClusterAddWeightedRoutingAction.INSTANCE
+        );
+        Map<String, Double> updatedWeights = Map.of("zone_A", 0.0, "zone_B", 2.0, "zone_C", 1.0);
+        WeightedRouting updatedWeightedRouting = new WeightedRouting("zone", updatedWeights);
+        request.setWeightedRouting(updatedWeightedRouting);
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<ClusterStateUpdateResponse> listener = new ActionListener<ClusterStateUpdateResponse>() {
+            @Override
+            public void onResponse(ClusterStateUpdateResponse clusterStateUpdateResponse) {
+                assertTrue(clusterStateUpdateResponse.isAcknowledged());
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        weightedRoutingService.registerWeightedRoutingMetadata(request.request(), listener);
+        assertTrue(countDownLatch.await(30, TimeUnit.SECONDS));
+        assertEquals(updatedWeightedRouting, clusterService.state().metadata().weightedRoutingMetadata().getWeightedRouting());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AddIncrementallyTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AddIncrementallyTests.java
index c1959a96bffcd..89cf5fe4f76c3 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/AddIncrementallyTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AddIncrementallyTests.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
@@ -48,7 +46,7 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
 
@@ -238,8 +236,8 @@ public void testMinimalRelocationsNoLimit() {
     }
 
     private void assertNumIndexShardsPerNode(ClusterState state, Matcher<Integer> matcher) {
-        for (ObjectCursor<String> index : state.routingTable().indicesRouting().keys()) {
-            assertNumIndexShardsPerNode(state, index.value, matcher);
+        for (final String index : state.routingTable().indicesRouting().keySet()) {
+            assertNumIndexShardsPerNode(state, index, matcher);
         }
     }
 
@@ -250,10 +248,10 @@ private void assertNumIndexShardsPerNode(ClusterState state, String index, Match
     }
 
     private void assertAtLeastOneIndexShardPerNode(ClusterState state) {
-        for (ObjectCursor<String> index : state.routingTable().indicesRouting().keys()) {
+        for (final String index : state.routingTable().indicesRouting().keySet()) {
 
             for (RoutingNode node : state.getRoutingNodes()) {
-                assertThat(node.shardsWithState(index.value, STARTED).size(), Matchers.greaterThanOrEqualTo(1));
+                assertThat(node.shardsWithState(index, STARTED).size(), Matchers.greaterThanOrEqualTo(1));
             }
         }
 
@@ -294,8 +292,8 @@ private ClusterState initCluster(
 
         Metadata metadata = metadataBuilder.build();
 
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            routingTableBuilder.addAsNew(cursor.value);
+        for (final IndexMetadata cursor : metadata.indices().values()) {
+            routingTableBuilder.addAsNew(cursor);
         }
 
         RoutingTable initialRoutingTable = routingTableBuilder.build();
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationCommandsTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationCommandsTests.java
index cda0f1afaf62c..951bf971eedc4 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationCommandsTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationCommandsTests.java
@@ -59,17 +59,17 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
 
@@ -737,7 +737,7 @@ public void testMoveShardToNonDataNode() {
             "test1",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         DiscoveryNode node2 = new DiscoveryNode(
@@ -808,7 +808,7 @@ public void testMoveShardFromNonDataNode() {
             "test1",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         DiscoveryNode node2 = new DiscoveryNode(
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationConstraintsTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationConstraintsTests.java
index d115ee0c515cc..90546620e9e3e 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationConstraintsTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationConstraintsTests.java
@@ -10,9 +10,15 @@
 
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.cluster.routing.allocation.allocator.LocalShardsBalancer;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsBalancer;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.CONSTRAINT_WEIGHT;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID;
+import static org.opensearch.cluster.routing.allocation.ConstraintTypes.INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID;
 import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -31,13 +37,18 @@ public void testSettings() {
         settings.put(BalancedShardsAllocator.INDEX_BALANCE_FACTOR_SETTING.getKey(), indexBalanceFactor);
         settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), shardBalance);
         settings.put(BalancedShardsAllocator.THRESHOLD_SETTING.getKey(), threshold);
+        settings.put(BalancedShardsAllocator.PREFER_PRIMARY_SHARD_BALANCE.getKey(), true);
 
         service.applySettings(settings.build());
 
         assertEquals(indexBalanceFactor, allocator.getIndexBalance(), 0.01);
         assertEquals(shardBalance, allocator.getShardBalance(), 0.01);
         assertEquals(threshold, allocator.getThreshold(), 0.01);
+        assertEquals(true, allocator.getPreferPrimaryBalance());
 
+        settings.put(BalancedShardsAllocator.PREFER_PRIMARY_SHARD_BALANCE.getKey(), false);
+        service.applySettings(settings.build());
+        assertEquals(false, allocator.getPreferPrimaryBalance());
     }
 
     /**
@@ -45,9 +56,10 @@ public void testSettings() {
      * for IndexShardPerNode constraint satisfied and breached.
      */
     public void testIndexShardsPerNodeConstraint() {
-        BalancedShardsAllocator.Balancer balancer = mock(BalancedShardsAllocator.Balancer.class);
+        ShardsBalancer balancer = mock(LocalShardsBalancer.class);
         BalancedShardsAllocator.ModelNode node = mock(BalancedShardsAllocator.ModelNode.class);
         AllocationConstraints constraints = new AllocationConstraints();
+        constraints.updateAllocationConstraint(INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID, true);
 
         int shardCount = randomIntBetween(1, 500);
         float avgShardsPerNode = 1.0f + (random().nextFloat()) * 999.0f;
@@ -56,9 +68,142 @@ public void testIndexShardsPerNodeConstraint() {
         when(node.numShards(anyString())).thenReturn(shardCount);
         when(node.getNodeId()).thenReturn("test-node");
 
-        long expectedWeight = (shardCount >= avgShardsPerNode) ? constraints.CONSTRAINT_WEIGHT : 0;
+        long expectedWeight = (shardCount >= avgShardsPerNode) ? CONSTRAINT_WEIGHT : 0;
         assertEquals(expectedWeight, constraints.weight(balancer, node, "index"));
 
     }
 
+    /**
+     * Test constraint evaluation logic when with different values of ConstraintMode
+     * for IndexShardPerNode constraint satisfied and breached.
+     */
+    public void testPerIndexPrimaryShardsConstraint() {
+        ShardsBalancer balancer = mock(LocalShardsBalancer.class);
+        BalancedShardsAllocator.ModelNode node = mock(BalancedShardsAllocator.ModelNode.class);
+        AllocationConstraints constraints = new AllocationConstraints();
+        constraints.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+
+        final String indexName = "test-index";
+        int perIndexPrimaryShardCount = 1;
+        float avgPerIndexPrimaryShardsPerNode = 2f;
+
+        when(balancer.avgPrimaryShardsPerNode(anyString())).thenReturn(avgPerIndexPrimaryShardsPerNode);
+        when(node.numPrimaryShards(anyString())).thenReturn(perIndexPrimaryShardCount);
+        when(node.getNodeId()).thenReturn("test-node");
+
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+
+        perIndexPrimaryShardCount = 3;
+        when(node.numPrimaryShards(anyString())).thenReturn(perIndexPrimaryShardCount);
+        assertEquals(CONSTRAINT_WEIGHT, constraints.weight(balancer, node, indexName));
+
+        constraints.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, false);
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+    }
+
+    /**
+     * Test constraint evaluation logic when per index primary shard count constraint is breached.
+     */
+    public void testGlobalPrimaryShardsConstraint() {
+        ShardsBalancer balancer = mock(LocalShardsBalancer.class);
+        BalancedShardsAllocator.ModelNode node = mock(BalancedShardsAllocator.ModelNode.class);
+        AllocationConstraints constraints = new AllocationConstraints();
+        constraints.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+
+        final String indexName = "test-index";
+        int primaryShardCount = 1;
+        float avgPrimaryShardsPerNode = 2f;
+
+        when(balancer.avgPrimaryShardsPerNode()).thenReturn(avgPrimaryShardsPerNode);
+        when(node.numPrimaryShards()).thenReturn(primaryShardCount);
+        when(node.getNodeId()).thenReturn("test-node");
+
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+
+        primaryShardCount = 3;
+        when(node.numPrimaryShards()).thenReturn(primaryShardCount);
+        assertEquals(CONSTRAINT_WEIGHT, constraints.weight(balancer, node, indexName));
+
+        constraints.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, false);
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+    }
+
+    /**
+     * Test constraint evaluation logic when both per index and global primary shard count constraint is breached.
+     */
+    public void testPrimaryShardsConstraints() {
+        ShardsBalancer balancer = mock(LocalShardsBalancer.class);
+        BalancedShardsAllocator.ModelNode node = mock(BalancedShardsAllocator.ModelNode.class);
+        AllocationConstraints constraints = new AllocationConstraints();
+        constraints.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+        constraints.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+
+        final String indexName = "test-index";
+        int perIndexPrimaryShardCount = 1;
+        float avgPerIndexPrimaryShardCount = 2;
+        int primaryShardCount = 2;
+        float avgPrimaryShardsPerNode = 4;
+
+        when(balancer.avgPrimaryShardsPerNode(indexName)).thenReturn(avgPerIndexPrimaryShardCount);
+        when(node.numPrimaryShards(indexName)).thenReturn(perIndexPrimaryShardCount);
+        when(balancer.avgPrimaryShardsPerNode()).thenReturn(avgPrimaryShardsPerNode);
+        when(node.numPrimaryShards()).thenReturn(primaryShardCount);
+        when(node.getNodeId()).thenReturn("test-node");
+
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+
+        // breaching global primary shard count but not per index primary shard count
+        primaryShardCount = 5;
+        when(node.numPrimaryShards()).thenReturn(primaryShardCount);
+        assertEquals(CONSTRAINT_WEIGHT, constraints.weight(balancer, node, indexName));
+
+        // when per index primary shard count constraint is also breached
+        perIndexPrimaryShardCount = 3;
+        when(node.numPrimaryShards(indexName)).thenReturn(perIndexPrimaryShardCount);
+        assertEquals(2 * CONSTRAINT_WEIGHT, constraints.weight(balancer, node, indexName));
+
+        // disable both constraints
+        constraints.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, false);
+        constraints.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, false);
+        assertEquals(0, constraints.weight(balancer, node, indexName));
+    }
+
+    /**
+     * Test constraint evaluation logic when with different values of ConstraintMode
+     * for IndexShardPerNode constraint satisfied and breached.
+     */
+    public void testAllConstraints() {
+        ShardsBalancer balancer = mock(LocalShardsBalancer.class);
+        BalancedShardsAllocator.ModelNode node = mock(BalancedShardsAllocator.ModelNode.class);
+        AllocationConstraints constraints = new AllocationConstraints();
+        constraints.updateAllocationConstraint(INDEX_SHARD_PER_NODE_BREACH_CONSTRAINT_ID, true);
+        constraints.updateAllocationConstraint(INDEX_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+        constraints.updateAllocationConstraint(CLUSTER_PRIMARY_SHARD_BALANCE_CONSTRAINT_ID, true);
+
+        final String indexName = "test-index";
+        int shardCount = randomIntBetween(1, 500);
+        float avgPerIndexShardsPerNode = 1.0f + (random().nextFloat()) * 999.0f;
+
+        int perIndexPrimaryShardCount = randomIntBetween(1, shardCount);
+        float avgPerIndexPrimaryShardsPerNode = (random().nextFloat()) * avgPerIndexShardsPerNode;
+
+        float avgPrimaryShardsPerNode = 1.0f + (random().nextFloat()) * 999.0f;
+        int primaryShardsPerNode = randomIntBetween(1, shardCount);
+
+        when(balancer.avgPrimaryShardsPerNode(indexName)).thenReturn(avgPerIndexPrimaryShardsPerNode);
+        when(node.numPrimaryShards(indexName)).thenReturn(perIndexPrimaryShardCount);
+
+        when(balancer.avgPrimaryShardsPerNode()).thenReturn(avgPrimaryShardsPerNode);
+        when(node.numPrimaryShards()).thenReturn(primaryShardsPerNode);
+
+        when(balancer.avgShardsPerNode(indexName)).thenReturn(avgPerIndexShardsPerNode);
+        when(node.numShards(indexName)).thenReturn(shardCount);
+        when(node.getNodeId()).thenReturn("test-node");
+
+        long expectedWeight = (shardCount >= (int) Math.ceil(avgPerIndexShardsPerNode)) ? CONSTRAINT_WEIGHT : 0;
+        expectedWeight += perIndexPrimaryShardCount > (int) Math.ceil(avgPerIndexPrimaryShardsPerNode) ? CONSTRAINT_WEIGHT : 0;
+        expectedWeight += primaryShardsPerNode >= (int) Math.ceil(avgPrimaryShardsPerNode) ? CONSTRAINT_WEIGHT : 0;
+        assertEquals(expectedWeight, constraints.weight(balancer, node, indexName));
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationServiceTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationServiceTests.java
index 38b71db27e02f..64d9c243304d8 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AllocationServiceTests.java
@@ -73,7 +73,6 @@
 import static org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_CONCURRENT_OUTGOING_RECOVERIES_SETTING;
 import static org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_PRIMARIES_RECOVERIES_SETTING;
 import static org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING;
-
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessAllocationTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessAllocationTests.java
index c9e427a178515..02966b835fae0 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessAllocationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessAllocationTests.java
@@ -35,23 +35,31 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
 import org.opensearch.cluster.routing.allocation.command.CancelAllocationCommand;
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
+import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import static java.util.Collections.singletonMap;
@@ -59,6 +67,7 @@
 import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.opensearch.cluster.routing.ShardRoutingState.UNASSIGNED;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.sameInstance;
@@ -971,4 +980,87 @@ public void testMultipleAwarenessAttributes() {
         assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(2));
         assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(0));
     }
+
+    public void testAllocationExplainForUnassignedShardsWithUnbalancedZones() {
+        Settings settings = Settings.builder()
+            .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+            .put(ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING.getKey(), 10)
+            .put(ClusterRebalanceAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ALLOW_REBALANCE_SETTING.getKey(), "always")
+            .put("cluster.routing.allocation.awareness.attributes", "zone")
+            .put("cluster.routing.allocation.awareness.force.zone.values", "a,b,c")
+            .build();
+
+        AllocationService strategy = createAllocationService(settings);
+
+        logger.info("Building initial routing table for 'testAllocationExplainForUnassignedShardsWithUnbalancedZones'");
+        Metadata metadata = Metadata.builder()
+            .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+            .build();
+
+        RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(initialRoutingTable)
+            .build();
+
+        logger.info("--> adding 3 nodes in different zones and do rerouting");
+        clusterState = ClusterState.builder(clusterState)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(newNode("A-0", singletonMap("zone", "a")))
+                    .add(newNode("A-1", singletonMap("zone", "a")))
+                    .add(newNode("B-0", singletonMap("zone", "b")))
+            )
+            .build();
+        clusterState = strategy.reroute(clusterState, "reroute");
+        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(0));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(1));
+
+        logger.info("--> start the shard (primary)");
+        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(1));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(1));
+        // One Shard is unassigned due to forced zone awareness
+        assertThat(clusterState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(1));
+
+        List<ShardRouting> unassignedShards = clusterState.getRoutingTable().shardsWithState(UNASSIGNED);
+
+        ClusterSettings EMPTY_CLUSTER_SETTINGS = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        // Add a new node in zone c
+        clusterState = ClusterState.builder(clusterState)
+            .nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("C-0", singletonMap("zone", "c"))))
+            .build();
+
+        final AwarenessAllocationDecider decider = new AwarenessAllocationDecider(settings, EMPTY_CLUSTER_SETTINGS);
+
+        final RoutingAllocation allocation = new RoutingAllocation(
+            new AllocationDeciders(Collections.singleton(decider)),
+            clusterState.getRoutingNodes(),
+            clusterState,
+            null,
+            null,
+            0L
+        );
+        allocation.debugDecision(true);
+
+        Decision decision = null;
+        RoutingNodes nodes = clusterState.getRoutingNodes();
+
+        for (RoutingNode node : nodes) {
+            // Try to allocate unassigned shard to A-0, fails because of forced zone awareness
+            if (node.nodeId().equals("A-0")) {
+                decision = decider.canAllocate(unassignedShards.get(0), node, allocation);
+                assertEquals(Decision.Type.NO, decision.type());
+                assertEquals(
+                    decision.getExplanation(),
+                    "there are too many copies of the shard allocated to nodes with attribute"
+                        + " [zone], there are [3] total configured shard copies for this shard id and [3]"
+                        + " total attribute values, expected the allocated shard count per attribute [2] to"
+                        + " be less than or equal to the upper bound of the required number of shards per attribute [1]"
+                );
+            }
+
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalanceTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalanceTests.java
new file mode 100644
index 0000000000000..019db47e74cc3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/AwarenessReplicaBalanceTests.java
@@ -0,0 +1,134 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
+import org.opensearch.cluster.metadata.AutoExpandReplicas;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+
+import java.util.Optional;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS;
+import static org.hamcrest.Matchers.equalTo;
+
+public class AwarenessReplicaBalanceTests extends OpenSearchAllocationTestCase {
+
+    private static final ClusterSettings EMPTY_CLUSTER_SETTINGS = new ClusterSettings(
+        Settings.EMPTY,
+        ClusterSettings.BUILT_IN_CLUSTER_SETTINGS
+    );
+
+    public void testNoForcedAwarenessAttribute() {
+        Settings settings = Settings.builder()
+            .put("cluster.routing.allocation.awareness.attributes", "rack_id")
+            .put(SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+            .build();
+        AutoExpandReplicas autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+        AwarenessReplicaBalance awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        assertThat(awarenessReplicaBalance.maxAwarenessAttributes(), equalTo(1));
+
+        assertEquals(awarenessReplicaBalance.validate(0, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(1, autoExpandReplica), Optional.empty());
+    }
+
+    public void testForcedAwarenessAttribute() {
+        // When auto expand replica settings is as per zone awareness
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .put(SETTING_AUTO_EXPAND_REPLICAS, "0-2")
+            .build();
+
+        AwarenessReplicaBalance awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        AutoExpandReplicas autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+        assertThat(awarenessReplicaBalance.maxAwarenessAttributes(), equalTo(3));
+        assertEquals(awarenessReplicaBalance.validate(2, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(1, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(0, autoExpandReplica), Optional.empty());
+
+        // When auto expand replica settings is passed as max cap
+        settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .put(SETTING_AUTO_EXPAND_REPLICAS, "0-all")
+            .build();
+
+        awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+
+        assertEquals(awarenessReplicaBalance.validate(2, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(1, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(0, autoExpandReplica), Optional.empty());
+
+        // when auto expand is not valid set as per zone awareness
+        settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .put(SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+            .build();
+
+        awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+
+        assertEquals(
+            awarenessReplicaBalance.validate(1, autoExpandReplica),
+            Optional.of("expected max cap on auto expand to be a multiple of total awareness attributes [3]")
+        );
+        assertEquals(
+            awarenessReplicaBalance.validate(2, autoExpandReplica),
+            Optional.of("expected max cap on auto expand to be a multiple of total awareness attributes [3]")
+        );
+
+        // When auto expand replica is not present
+        settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "rack.values", "c, d, e")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .build();
+
+        awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+
+        assertEquals(awarenessReplicaBalance.validate(2, autoExpandReplica), Optional.empty());
+        assertEquals(
+            awarenessReplicaBalance.validate(1, autoExpandReplica),
+            Optional.of("expected total copies needs to be a multiple of total awareness attributes [3]")
+        );
+        assertEquals(
+            awarenessReplicaBalance.validate(0, autoExpandReplica),
+            Optional.of("expected total copies needs to be a multiple of total awareness attributes [3]")
+        );
+
+    }
+
+    public void testForcedAwarenessAttributeDisabled() {
+        Settings settings = Settings.builder()
+            .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone, rack")
+            .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+            .put(SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+            .build();
+
+        AwarenessReplicaBalance awarenessReplicaBalance = new AwarenessReplicaBalance(settings, EMPTY_CLUSTER_SETTINGS);
+        AutoExpandReplicas autoExpandReplica = AutoExpandReplicas.SETTING.get(settings);
+
+        assertThat(awarenessReplicaBalance.maxAwarenessAttributes(), equalTo(1));
+        assertEquals(awarenessReplicaBalance.validate(0, autoExpandReplica), Optional.empty());
+        assertEquals(awarenessReplicaBalance.validate(1, autoExpandReplica), Optional.empty());
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/BalanceConfigurationTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/BalanceConfigurationTests.java
index 1ba69694eaec1..f87bc8cb425f2 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/BalanceConfigurationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/BalanceConfigurationTests.java
@@ -32,34 +32,50 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.ArrayUtil;
 import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.cluster.routing.TestShardRouting;
+import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
 import org.opensearch.cluster.routing.allocation.allocator.ShardsAllocator;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 import org.hamcrest.Matchers;
 
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_CREATION_DATE;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.opensearch.cluster.routing.ShardRoutingState.UNASSIGNED;
 
@@ -75,7 +91,7 @@ public class BalanceConfigurationTests extends OpenSearchAllocationTestCase {
     public void testIndexBalance() {
         /* Tests balance over indices only */
         final float indexBalance = 1.0f;
-        final float replicaBalance = 0.0f;
+        final float shardBalance = 0.0f;
         final float balanceThreshold = 1.0f;
 
         Settings.Builder settings = Settings.builder();
@@ -84,7 +100,7 @@ public void testIndexBalance() {
             ClusterRebalanceAllocationDecider.ClusterRebalanceType.ALWAYS.toString()
         );
         settings.put(BalancedShardsAllocator.INDEX_BALANCE_FACTOR_SETTING.getKey(), indexBalance);
-        settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), replicaBalance);
+        settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), shardBalance);
         settings.put(BalancedShardsAllocator.THRESHOLD_SETTING.getKey(), balanceThreshold);
 
         AllocationService strategy = createAllocationService(settings.build(), new TestGatewayAllocator());
@@ -123,10 +139,428 @@ public void testIndexBalance() {
         );
     }
 
-    public void testReplicaBalance() {
+    private Settings.Builder getSettingsBuilderForPrimaryBalance() {
+        return getSettingsBuilderForPrimaryBalance(true);
+    }
+
+    private Settings.Builder getSettingsBuilderForPrimaryBalance(boolean preferPrimaryBalance) {
+        final float indexBalance = 0.55f;
+        final float shardBalance = 0.45f;
+        final float balanceThreshold = 1.0f;
+
+        Settings.Builder settings = Settings.builder();
+        settings.put(
+            ClusterRebalanceAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ALLOW_REBALANCE_SETTING.getKey(),
+            ClusterRebalanceAllocationDecider.ClusterRebalanceType.ALWAYS.toString()
+        );
+        settings.put(BalancedShardsAllocator.INDEX_BALANCE_FACTOR_SETTING.getKey(), indexBalance);
+        settings.put(BalancedShardsAllocator.PREFER_PRIMARY_SHARD_BALANCE.getKey(), preferPrimaryBalance);
+        settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), shardBalance);
+        settings.put(BalancedShardsAllocator.THRESHOLD_SETTING.getKey(), balanceThreshold);
+        return settings;
+    }
+
+    private IndexMetadata getIndexMetadata(String indexName, int shardCount, int replicaCount) {
+        return IndexMetadata.builder(indexName)
+            .settings(
+                Settings.builder()
+                    .put(SETTING_VERSION_CREATED, Version.CURRENT)
+                    .put(SETTING_NUMBER_OF_SHARDS, shardCount)
+                    .put(SETTING_NUMBER_OF_REPLICAS, replicaCount)
+                    .put(SETTING_CREATION_DATE, System.currentTimeMillis())
+            )
+            .build();
+    }
+
+    /**
+     * This test verifies that with only primary shard balance, the primary shard distribution per index is balanced.
+     */
+    public void testPrimaryBalance() {
+        AllocationService strategy = createAllocationService(getSettingsBuilderForPrimaryBalance().build(), new TestGatewayAllocator());
+
+        ClusterState clusterState = initCluster(strategy);
+        verifyPerIndexPrimaryBalance(clusterState);
+
+        clusterState = addNode(clusterState, strategy);
+        verifyPerIndexPrimaryBalance(clusterState);
+
+        clusterState = removeNodes(clusterState, strategy);
+        verifyPerIndexPrimaryBalance(clusterState);
+    }
+
+    /**
+     * This test verifies primary shard balance is not attained without PREFER_PRIMARY_SHARD_BALANCE setting.
+     */
+    public void testPrimaryBalanceWithoutPreferPrimaryBalanceSetting() {
+        final int numberOfNodes = 5;
+        final int numberOfIndices = 5;
+        final int numberOfShards = 25;
+        final int numberOfReplicas = 1;
+
+        final int numberOfRuns = 5;
+        int balanceFailed = 0;
+
+        AllocationService strategy = createAllocationService(
+            getSettingsBuilderForPrimaryBalance(false).build(),
+            new TestGatewayAllocator()
+        );
+        for (int i = 0; i < numberOfRuns; i++) {
+            ClusterState clusterState = initCluster(strategy, numberOfIndices, numberOfNodes, numberOfShards, numberOfReplicas);
+            clusterState = removeOneNode(clusterState, strategy);
+            logger.info(ShardAllocations.printShardDistribution(clusterState));
+            try {
+                verifyPerIndexPrimaryBalance(clusterState);
+            } catch (AssertionError e) {
+                balanceFailed++;
+                logger.info("Expected assertion failure");
+            }
+        }
+        assertTrue(balanceFailed >= 4);
+    }
+
+    /**
+     * This test verifies primary shard balance is attained with PREFER_PRIMARY_SHARD_BALANCE setting.
+     */
+    public void testPrimaryBalanceWithPreferPrimaryBalanceSetting() {
+        final int numberOfNodes = 5;
+        final int numberOfIndices = 5;
+        final int numberOfShards = 25;
+        final int numberOfReplicas = 1;
+        final int numberOfRuns = 5;
+        int balanceFailed = 0;
+
+        AllocationService strategy = createAllocationService(getSettingsBuilderForPrimaryBalance().build(), new TestGatewayAllocator());
+        for (int i = 0; i < numberOfRuns; i++) {
+            ClusterState clusterState = initCluster(strategy, numberOfIndices, numberOfNodes, numberOfShards, numberOfReplicas);
+            clusterState = removeOneNode(clusterState, strategy);
+            logger.info(ShardAllocations.printShardDistribution(clusterState));
+            try {
+                verifyPerIndexPrimaryBalance(clusterState);
+            } catch (AssertionError e) {
+                balanceFailed++;
+                logger.info("Unexpected assertion failure");
+            }
+        }
+        assertTrue(balanceFailed <= 1);
+    }
+
+    /**
+     * This test verifies the allocation logic when nodes breach multiple constraints and ensure node breaching min
+     * constraints chosen for allocation.
+     *
+     * This test mimics a cluster state containing four nodes, where one node breaches two constraints while one breaches
+     * only one. In order to have nodes breach constraints, test excludes two nodes (node2, node3) from allocation so
+     * that other two nodes (node0, node1) have all shards assignments resulting in constraints breach. Test asserts that
+     * the new primary shard assignment lands on the node breaching one constraint(node1), while replica land on the other
+     * (node0). Final shard allocation state.
+     *
+     routing_nodes:
+     -----node_id[node2][V]
+     -----node_id[node3][V]
+     -----node_id[node0][V]
+     --------[test][1], node[node0], [P], s[STARTED], a[id=7B4dVsrjSoC6imBHO60mrQ]
+     --------[test][0], node[node0], [P], s[STARTED], a[id=0HySaPcyRhiKrH6QLA3evw]
+     --------[test][2], node[node0], [R], s[STARTED], a[id=pB3iuLKZSC--2yNS0trbgA]
+     -----node_id[node1][V]
+     --------[test][2], node[node1], [P], s[STARTED], a[id=QWN_T6xpQiWGSD8GJnX-bQ]
+     --------[test][1], node[node1], [R], s[STARTED], a[id=ChWdQiOdSdKrTPxwceIu1w]
+     --------[test][0], node[node1], [R], s[STARTED], a[id=5Adc5JteQ8-lY2xfsHUg-Q]
+     *
+     */
+    public void testPrimaryBalanceWithContrainstBreaching() {
+        // Mark node2, node 3 excluded (FilterAllocationDecider) so that all allocations land on node 0, node 1
+        Settings.Builder settingsBuilder = getSettingsBuilderForPrimaryBalance();
+        settingsBuilder.put("cluster.routing.allocation.exclude._id", "node2,node3");
+
+        AllocationService strategy = createAllocationService(settingsBuilder.build(), new TestGatewayAllocator());
+        DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
+        List<String> nodesList = new ArrayList<>();
+        for (int i = 0; i < 4; i++) {
+            final DiscoveryNode node = newNode("node" + i);
+            discoBuilder = discoBuilder.add(node);
+            nodesList.add(node.getId());
+        }
+        discoBuilder.localNodeId(newNode("node_0").getId());
+        discoBuilder.clusterManagerNodeId(newNode("node_0").getId());
+
+        Metadata.Builder metadata = Metadata.builder();
+        metadata.persistentSettings(settingsBuilder.build());
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        // build index metadata
+        IndexMetadata indexMetadata = getIndexMetadata("test", 3, 1);
+        // Build index routing table
+        IndexRoutingTable.Builder indexRoutingTable = IndexRoutingTable.builder(indexMetadata.getIndex());
+        ShardId shardId_0 = new ShardId(indexMetadata.getIndex(), 0);
+        ShardId shardId_1 = new ShardId(indexMetadata.getIndex(), 1);
+        ShardId shardId_2 = new ShardId(indexMetadata.getIndex(), 2);
+        UnassignedInfo unassignedInfo = new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, null);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_0 = new IndexShardRoutingTable.Builder(shardId_0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_1 = new IndexShardRoutingTable.Builder(shardId_1);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_2 = new IndexShardRoutingTable.Builder(shardId_2);
+        indexShardRoutingBuilder_0.addShard(TestShardRouting.newShardRouting(shardId_0, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_1.addShard(TestShardRouting.newShardRouting(shardId_1, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_0.addShard(
+            TestShardRouting.newShardRouting(shardId_0, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexShardRoutingBuilder_1.addShard(
+            TestShardRouting.newShardRouting(shardId_1, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexShardRoutingBuilder_2.addShard(
+            TestShardRouting.newShardRouting(
+                shardId_2,
+                null,
+                null,
+                true,
+                UNASSIGNED,
+                RecoverySource.EmptyStoreRecoverySource.INSTANCE,
+                unassignedInfo
+            )
+        );
+        indexShardRoutingBuilder_2.addShard(
+            TestShardRouting.newShardRouting(
+                shardId_2,
+                null,
+                null,
+                false,
+                UNASSIGNED,
+                RecoverySource.PeerRecoverySource.INSTANCE,
+                unassignedInfo
+            )
+        );
+
+        IndexShardRoutingTable indexShardRoutingTable_0 = indexShardRoutingBuilder_0.build();
+        IndexShardRoutingTable indexShardRoutingTable_1 = indexShardRoutingBuilder_1.build();
+
+        indexRoutingTable.addIndexShard(indexShardRoutingBuilder_0.build());
+        indexRoutingTable.addIndexShard(indexShardRoutingBuilder_1.build());
+        indexRoutingTable.addIndexShard(indexShardRoutingBuilder_2.build());
+        routingTable.add(indexRoutingTable);
+
+        IndexMetadata.Builder indexMetaDataBuilder = IndexMetadata.builder(indexMetadata);
+        indexMetaDataBuilder.putInSyncAllocationIds(0, indexShardRoutingTable_0.getAllAllocationIds());
+        indexMetaDataBuilder.putInSyncAllocationIds(1, indexShardRoutingTable_1.getAllAllocationIds());
+        metadata.put(indexMetaDataBuilder.build(), false);
+
+        ClusterState.Builder stateBuilder = ClusterState.builder(new ClusterName("test"));
+        stateBuilder.nodes(discoBuilder);
+        stateBuilder.metadata(metadata.generateClusterUuidIfNeeded().build());
+        stateBuilder.routingTable(routingTable.build());
+        ClusterState clusterState = stateBuilder.build();
+        clusterState = strategy.reroute(clusterState, "reroute");
+        clusterState = applyAllocationUntilNoChange(clusterState, strategy);
+
+        logger.info(ShardAllocations.printShardDistribution(clusterState));
+        ShardRouting primaryShard = clusterState.routingTable().shardRoutingTable(shardId_2).primaryShard();
+        List<ShardRouting> replicaShards = clusterState.routingTable().shardRoutingTable(shardId_2).replicaShards();
+
+        assertTrue(primaryShard.started());
+        assertEquals("node1", primaryShard.currentNodeId());
+
+        assertEquals(1, replicaShards.size());
+        assertTrue(replicaShards.get(0).started());
+        assertEquals("node0", replicaShards.get(0).currentNodeId());
+    }
+
+    /**
+     * This test verifies global balance by creating indices iteratively and verify primary shards do not pile up on one
+     * node.
+     * @throws Exception generic exception
+     */
+    public void testGlobalPrimaryBalance() throws Exception {
+        AllocationService strategy = createAllocationService(getSettingsBuilderForPrimaryBalance().build(), new TestGatewayAllocator());
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .build();
+        clusterState = addNode(clusterState, strategy);
+        clusterState = addNode(clusterState, strategy);
+
+        clusterState = addIndex(clusterState, strategy, "test-index1", 1, 1);
+        clusterState = addIndex(clusterState, strategy, "test-index2", 1, 1);
+        clusterState = addIndex(clusterState, strategy, "test-index3", 1, 1);
+
+        logger.info(ShardAllocations.printShardDistribution(clusterState));
+        verifyPrimaryBalance(clusterState);
+    }
+
+    /**
+     * This test mimics a cluster state which can not be rebalanced due to
+     * {@link org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider}
+     * allocation decider which prevents shard relocation, leaving cluster unbalanced on primaries.
+     *
+     * There are two nodes (N1, N2) where all primaries land on N1 while replicas on N2.
+     * N1        N2
+     * ------  --------
+     * P1        R1
+     * P2        R2
+     *
+     * -----node_id[node_0][V]
+     * --------[test][1], node[node_0], [P], s[STARTED], a[id=xqfZSToVSQaff2xvuxh_yA]
+     * --------[test][0], node[node_0], [P], s[STARTED], a[id=VGjOeBGdSmu3pJR6T7v29A]
+     * -----node_id[node_1][V]
+     * --------[test][1], node[node_1], [R], s[STARTED], a[id=zZI0R8FBQkWMNndEZt9d8w]
+     * --------[test][0], node[node_1], [R], s[STARTED], a[id=8IpwEMQ2QEuj5rQOxBagSA]
+     */
+    public void testPrimaryBalance_NotSolved_1() {
+        AllocationService strategy = createAllocationService(getSettingsBuilderForPrimaryBalance().build(), new TestGatewayAllocator());
+
+        DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
+        Set<String> nodes = new HashSet<>();
+        for (int i = 0; i < 2; i++) {
+            final DiscoveryNode node = newNode("node_" + i);
+            discoBuilder = discoBuilder.add(node);
+            nodes.add(node.getId());
+        }
+        discoBuilder.localNodeId(newNode("node_0").getId());
+        discoBuilder.clusterManagerNodeId(newNode("node_0").getId());
+        Metadata.Builder metadata = Metadata.builder();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        List<String> nodesList = new ArrayList<>(nodes);
+        // build index metadata
+        IndexMetadata indexMetadata = getIndexMetadata("test", 2, 1);
+        IndexRoutingTable.Builder indexRoutingTable = IndexRoutingTable.builder(indexMetadata.getIndex());
+        ShardId shardId_0 = new ShardId(indexMetadata.getIndex(), 0);
+        ShardId shardId_1 = new ShardId(indexMetadata.getIndex(), 1);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_0 = new IndexShardRoutingTable.Builder(shardId_0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_1 = new IndexShardRoutingTable.Builder(shardId_1);
+        indexShardRoutingBuilder_0.addShard(TestShardRouting.newShardRouting(shardId_0, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_1.addShard(TestShardRouting.newShardRouting(shardId_1, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_0.addShard(
+            TestShardRouting.newShardRouting(shardId_0, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexShardRoutingBuilder_1.addShard(
+            TestShardRouting.newShardRouting(shardId_1, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexRoutingTable.addIndexShard(indexShardRoutingBuilder_0.build());
+        indexRoutingTable.addIndexShard(indexShardRoutingBuilder_1.build());
+        metadata.put(indexMetadata, false);
+        routingTable.add(indexRoutingTable);
+
+        ClusterState.Builder stateBuilder = ClusterState.builder(new ClusterName("test"));
+        stateBuilder.nodes(discoBuilder);
+        stateBuilder.metadata(metadata.generateClusterUuidIfNeeded().build());
+        stateBuilder.routingTable(routingTable.build());
+        ClusterState clusterState = stateBuilder.build();
+
+        clusterState = strategy.reroute(clusterState, "reroute");
+        boolean balanced = true;
+        logger.info(ShardAllocations.printShardDistribution(clusterState));
+        try {
+            verifyPerIndexPrimaryBalance(clusterState);
+        } catch (AssertionError e) {
+            balanced = false;
+        }
+        assertFalse(balanced);
+    }
+
+    /**
+     * This test mimics cluster state where re-balancing is not possible due to existing limitation of re-balancing
+     * logic which applies at index level i.e. balance shards single index across all nodes. This will be solved when
+     * primary shard count across indices, constraint is added.
+     *
+     * Please note, P1, P2 belongs to different index
+     *
+     * N1        N2
+     * ------  --------
+     * P1       R1
+     * P2       R2
+     *
+     * -----node_id[node_0][V]
+     * --------[test1][0], node[node_0], [P], s[STARTED], a[id=u7qtyy5AR42hgEa-JpeArg]
+     * --------[test0][0], node[node_0], [P], s[STARTED], a[id=BQrLSo6sQyGlcLdVvGgqLQ]
+     * -----node_id[node_1][V]
+     * --------[test1][0], node[node_1], [R], s[STARTED], a[id=TDqbfvAfSFK6lnv3aOU9bA]
+     * --------[test0][0], node[node_1], [R], s[STARTED], a[id=E85-jhiEQwuB43u5Wq1mAw]
+     *
+     */
+    public void testPrimaryBalance_NotSolved_2() {
+        AllocationService strategy = createAllocationService(getSettingsBuilderForPrimaryBalance().build(), new TestGatewayAllocator());
+
+        DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
+        Set<String> nodes = new HashSet<>();
+        for (int i = 0; i < 2; i++) {
+            final DiscoveryNode node = newNode("node_" + i);
+            discoBuilder = discoBuilder.add(node);
+            nodes.add(node.getId());
+        }
+        discoBuilder.localNodeId(newNode("node_0").getId());
+        discoBuilder.clusterManagerNodeId(newNode("node_0").getId());
+        Metadata.Builder metadata = Metadata.builder();
+        RoutingTable.Builder routingTable = RoutingTable.builder();
+        List<String> nodesList = new ArrayList<>(nodes);
+        // build index metadata
+        IndexMetadata indexMetadata_0 = getIndexMetadata("test0", 1, 1);
+        IndexMetadata indexMetadata_1 = getIndexMetadata("test1", 1, 1);
+        IndexRoutingTable.Builder indexRoutingTable_0 = IndexRoutingTable.builder(indexMetadata_0.getIndex());
+        IndexRoutingTable.Builder indexRoutingTable_1 = IndexRoutingTable.builder(indexMetadata_1.getIndex());
+        ShardId shardId_0 = new ShardId(indexMetadata_0.getIndex(), 0);
+        ShardId shardId_1 = new ShardId(indexMetadata_1.getIndex(), 0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_0 = new IndexShardRoutingTable.Builder(shardId_0);
+        IndexShardRoutingTable.Builder indexShardRoutingBuilder_1 = new IndexShardRoutingTable.Builder(shardId_1);
+        indexShardRoutingBuilder_0.addShard(TestShardRouting.newShardRouting(shardId_0, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_1.addShard(TestShardRouting.newShardRouting(shardId_1, nodesList.get(0), true, ShardRoutingState.STARTED));
+        indexShardRoutingBuilder_0.addShard(
+            TestShardRouting.newShardRouting(shardId_0, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexShardRoutingBuilder_1.addShard(
+            TestShardRouting.newShardRouting(shardId_1, nodesList.get(1), false, ShardRoutingState.STARTED)
+        );
+        indexRoutingTable_0.addIndexShard(indexShardRoutingBuilder_0.build());
+        indexRoutingTable_1.addIndexShard(indexShardRoutingBuilder_1.build());
+        metadata.put(indexMetadata_0, false);
+        metadata.put(indexMetadata_1, false);
+        routingTable.add(indexRoutingTable_0);
+        routingTable.add(indexRoutingTable_1);
+        ClusterState.Builder stateBuilder = ClusterState.builder(new ClusterName("test"));
+        stateBuilder.nodes(discoBuilder);
+        stateBuilder.metadata(metadata.generateClusterUuidIfNeeded().build());
+        stateBuilder.routingTable(routingTable.build());
+        ClusterState clusterState = stateBuilder.build();
+
+        clusterState = strategy.reroute(clusterState, "reroute");
+        logger.info(ShardAllocations.printShardDistribution(clusterState));
+        // The cluster is balanced when considering indices individually not balanced when considering global state
+        verifyPerIndexPrimaryBalance(clusterState);
+    }
+
+    private void verifyPerIndexPrimaryBalance(ClusterState currentState) {
+        RoutingNodes nodes = currentState.getRoutingNodes();
+        for (final Map.Entry<String, IndexRoutingTable> index : currentState.getRoutingTable().indicesRouting().entrySet()) {
+            final int totalPrimaryShards = index.getValue().primaryShardsActive();
+            final int avgPrimaryShardsPerNode = (int) Math.ceil(totalPrimaryShards * 1f / currentState.getRoutingNodes().size());
+
+            for (RoutingNode node : nodes) {
+                final int primaryCount = node.shardsWithState(index.getKey(), STARTED)
+                    .stream()
+                    .filter(ShardRouting::primary)
+                    .collect(Collectors.toList())
+                    .size();
+                assertTrue(primaryCount <= avgPrimaryShardsPerNode);
+            }
+        }
+    }
+
+    private void verifyPrimaryBalance(ClusterState clusterState) throws Exception {
+        assertBusy(() -> {
+            RoutingNodes nodes = clusterState.getRoutingNodes();
+            int totalPrimaryShards = 0;
+            for (final IndexRoutingTable index : clusterState.getRoutingTable().indicesRouting().values()) {
+                totalPrimaryShards += index.primaryShardsActive();
+            }
+            final int avgPrimaryShardsPerNode = (int) Math.ceil(totalPrimaryShards * 1f / clusterState.getRoutingNodes().size());
+            for (RoutingNode node : nodes) {
+                final int primaryCount = node.shardsWithState(STARTED)
+                    .stream()
+                    .filter(ShardRouting::primary)
+                    .collect(Collectors.toList())
+                    .size();
+                assertTrue(primaryCount <= avgPrimaryShardsPerNode);
+            }
+        }, 60, TimeUnit.SECONDS);
+    }
+
+    public void testShardBalance() {
         /* Tests balance over replicas only */
         final float indexBalance = 0.0f;
-        final float replicaBalance = 1.0f;
+        final float shardBalance = 1.0f;
         final float balanceThreshold = 1.0f;
 
         Settings.Builder settings = Settings.builder();
@@ -135,13 +569,13 @@ public void testReplicaBalance() {
             ClusterRebalanceAllocationDecider.ClusterRebalanceType.ALWAYS.toString()
         );
         settings.put(BalancedShardsAllocator.INDEX_BALANCE_FACTOR_SETTING.getKey(), indexBalance);
-        settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), replicaBalance);
+        settings.put(BalancedShardsAllocator.SHARD_BALANCE_FACTOR_SETTING.getKey(), shardBalance);
         settings.put(BalancedShardsAllocator.THRESHOLD_SETTING.getKey(), balanceThreshold);
 
         AllocationService strategy = createAllocationService(settings.build(), new TestGatewayAllocator());
 
         ClusterState clusterState = initCluster(strategy);
-        assertReplicaBalance(
+        assertShardBalance(
             clusterState.getRoutingNodes(),
             numberOfNodes,
             numberOfIndices,
@@ -151,7 +585,7 @@ public void testReplicaBalance() {
         );
 
         clusterState = addNode(clusterState, strategy);
-        assertReplicaBalance(
+        assertShardBalance(
             clusterState.getRoutingNodes(),
             numberOfNodes + 1,
             numberOfIndices,
@@ -161,7 +595,7 @@ public void testReplicaBalance() {
         );
 
         clusterState = removeNodes(clusterState, strategy);
-        assertReplicaBalance(
+        assertShardBalance(
             clusterState.getRoutingNodes(),
             numberOfNodes + 1 - (numberOfNodes + 1) / 2,
             numberOfIndices,
@@ -172,21 +606,56 @@ public void testReplicaBalance() {
     }
 
     private ClusterState initCluster(AllocationService strategy) {
+        return initCluster(strategy, numberOfIndices, numberOfNodes, numberOfShards, numberOfReplicas);
+    }
+
+    private ClusterState addIndex(
+        ClusterState clusterState,
+        AllocationService strategy,
+        String indexName,
+        int numberOfShards,
+        int numberOfReplicas
+    ) {
+        Metadata.Builder metadataBuilder = Metadata.builder(clusterState.getMetadata());
+        RoutingTable.Builder routingTableBuilder = RoutingTable.builder(clusterState.routingTable());
+
+        IndexMetadata.Builder index = IndexMetadata.builder(indexName)
+            .settings(settings(Version.CURRENT))
+            .numberOfShards(numberOfShards)
+            .numberOfReplicas(numberOfReplicas);
+
+        metadataBuilder = metadataBuilder.put(index);
+        routingTableBuilder.addAsNew(index.build());
+
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(metadataBuilder.build())
+            .routingTable(routingTableBuilder.build())
+            .build();
+        clusterState = strategy.reroute(clusterState, "index-created");
+        return applyAllocationUntilNoChange(clusterState, strategy);
+    }
+
+    private ClusterState initCluster(
+        AllocationService strategy,
+        int numberOfIndices,
+        int numberOfNodes,
+        int numberOfShards,
+        int numberOfReplicas
+    ) {
         Metadata.Builder metadataBuilder = Metadata.builder();
         RoutingTable.Builder routingTableBuilder = RoutingTable.builder();
 
         for (int i = 0; i < numberOfIndices; i++) {
             IndexMetadata.Builder index = IndexMetadata.builder("test" + i)
-                .settings(settings(Version.CURRENT))
+                .settings(settings(Version.CURRENT).build())
                 .numberOfShards(numberOfShards)
                 .numberOfReplicas(numberOfReplicas);
             metadataBuilder = metadataBuilder.put(index);
         }
 
         Metadata metadata = metadataBuilder.build();
-
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            routingTableBuilder.addAsNew(cursor.value);
+        for (final IndexMetadata cursor : metadata.indices().values()) {
+            routingTableBuilder.addAsNew(cursor);
         }
 
         RoutingTable initialRoutingTable = routingTableBuilder.build();
@@ -202,21 +671,13 @@ private ClusterState initCluster(AllocationService strategy) {
             .routingTable(initialRoutingTable)
             .build();
         clusterState = strategy.reroute(clusterState, "reroute");
-
-        logger.info("restart all the primary shards, replicas will start initializing");
-        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
-
-        logger.info("start the replica shards");
-        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
-
-        logger.info("complete rebalancing");
-        return applyStartedShardsUntilNoChange(clusterState, strategy);
+        return applyAllocationUntilNoChange(clusterState, strategy);
     }
 
     private ClusterState addNode(ClusterState clusterState, AllocationService strategy) {
         logger.info("now, start 1 more node, check that rebalancing will happen because we set it to always");
         clusterState = ClusterState.builder(clusterState)
-            .nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node" + numberOfNodes)))
+            .nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node" + clusterState.getRoutingNodes().size())))
             .build();
 
         RoutingTable routingTable = strategy.reroute(clusterState, "reroute").routingTable();
@@ -226,7 +687,16 @@ private ClusterState addNode(ClusterState clusterState, AllocationService strate
         return applyStartedShardsUntilNoChange(clusterState, strategy);
     }
 
+    private ClusterState removeOneNode(ClusterState clusterState, AllocationService strategy) {
+        DiscoveryNodes.Builder nodes = DiscoveryNodes.builder(clusterState.nodes());
+        nodes.remove("node0");
+        clusterState = ClusterState.builder(clusterState).nodes(nodes.build()).build();
+        clusterState = strategy.disassociateDeadNodes(clusterState, randomBoolean(), "removed nodes");
+        return applyAllocationUntilNoChange(clusterState, strategy);
+    }
+
     private ClusterState removeNodes(ClusterState clusterState, AllocationService strategy) {
+        int numberOfNodes = clusterState.getRoutingNodes().size();
         logger.info("Removing half the nodes (" + (numberOfNodes + 1) / 2 + ")");
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder(clusterState.nodes());
 
@@ -240,7 +710,10 @@ private ClusterState removeNodes(ClusterState clusterState, AllocationService st
         if (removed) {
             clusterState = strategy.disassociateDeadNodes(clusterState, randomBoolean(), "removed nodes");
         }
+        return applyAllocationUntilNoChange(clusterState, strategy);
+    }
 
+    private ClusterState applyAllocationUntilNoChange(ClusterState clusterState, AllocationService strategy) {
         logger.info("start all the primary shards, replicas will start initializing");
         clusterState = startInitializingShardsAndReroute(strategy, clusterState);
 
@@ -254,7 +727,7 @@ private ClusterState removeNodes(ClusterState clusterState, AllocationService st
         return applyStartedShardsUntilNoChange(clusterState, strategy);
     }
 
-    private void assertReplicaBalance(
+    private void assertShardBalance(
         RoutingNodes nodes,
         int numberOfNodes,
         int numberOfIndices,
@@ -301,10 +774,10 @@ private void assertIndexBalance(
         final int minAvgNumberOfShards = Math.round(Math.round(Math.floor(avgNumShards - threshold)));
         final int maxAvgNumberOfShards = Math.round(Math.round(Math.ceil(avgNumShards + threshold)));
 
-        for (ObjectCursor<String> index : routingTable.indicesRouting().keys()) {
+        for (final String index : routingTable.indicesRouting().keySet()) {
             for (RoutingNode node : nodes) {
-                assertThat(node.shardsWithState(index.value, STARTED).size(), Matchers.greaterThanOrEqualTo(minAvgNumberOfShards));
-                assertThat(node.shardsWithState(index.value, STARTED).size(), Matchers.lessThanOrEqualTo(maxAvgNumberOfShards));
+                assertThat(node.shardsWithState(index, STARTED).size(), Matchers.greaterThanOrEqualTo(minAvgNumberOfShards));
+                assertThat(node.shardsWithState(index, STARTED).size(), Matchers.lessThanOrEqualTo(maxAvgNumberOfShards));
             }
         }
     }
@@ -436,8 +909,8 @@ public ShardAllocationDecision decideShardAllocation(ShardRouting shard, Routing
             .numberOfReplicas(1);
         metadataBuilder = metadataBuilder.put(indexMeta);
         Metadata metadata = metadataBuilder.build();
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            routingTableBuilder.addAsNew(cursor.value);
+        for (final IndexMetadata cursor : metadata.indices().values()) {
+            routingTableBuilder.addAsNew(cursor);
         }
         RoutingTable routingTable = routingTableBuilder.build();
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder();
@@ -494,5 +967,4 @@ public ShardAllocationDecision decideShardAllocation(ShardRouting shard, Routing
             }
         }
     }
-
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/BalancedSingleShardTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/BalancedSingleShardTests.java
index a7b53a4c4bc8b..d29249cef0818 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/BalancedSingleShardTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/BalancedSingleShardTests.java
@@ -43,7 +43,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
-import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator.Balancer;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsBalancer;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
@@ -65,7 +65,7 @@
 import static org.hamcrest.Matchers.startsWith;
 
 /**
- * Tests for balancing a single shard, see {@link Balancer#decideRebalance(ShardRouting)}.
+ * Tests for balancing a single shard, see {@link ShardsBalancer#decideRebalance(ShardRouting)}.
  */
 public class BalancedSingleShardTests extends OpenSearchAllocationTestCase {
 
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/DecisionsImpactOnClusterHealthTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/DecisionsImpactOnClusterHealthTests.java
index 35c6aea425b88..fbcfbd6082fd6 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/DecisionsImpactOnClusterHealthTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/DecisionsImpactOnClusterHealthTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.health.ClusterHealthStatus;
 import org.opensearch.cluster.health.ClusterStateHealth;
 import org.opensearch.cluster.metadata.IndexMetadata;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
index 9f3f603e8edf3..6ab57d10b05c1 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
@@ -34,7 +34,6 @@
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterInfo;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -49,22 +48,28 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.common.Priority;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.junit.annotations.TestLogging;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.LongSupplier;
 
+import static org.opensearch.cluster.routing.allocation.DiskThresholdSettings.CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -129,21 +134,26 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
                 assertTrue(readOnly);
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
-        ImmutableOpenMap.Builder<String, DiskUsage> builder = ImmutableOpenMap.builder();
+        Map<String, DiskUsage> builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 4));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 30));
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertFalse(reroute.get());
         assertEquals(new HashSet<>(Arrays.asList("test_1", "test_2")), indices.get());
 
         indices.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 4));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 5));
         currentTime.addAndGet(randomLongBetween(60001, 120000));
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertTrue(reroute.get());
         assertEquals(new HashSet<>(Arrays.asList("test_1", "test_2")), indices.get());
         IndexMetadata indexMetadata = IndexMetadata.builder(clusterState.metadata().index("test_2"))
@@ -185,14 +195,19 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
                 assertTrue(readOnly);
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
         indices.set(null);
         reroute.set(false);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 4));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 5));
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertTrue(reroute.get());
         assertEquals(Collections.singleton("test_1"), indices.get());
     }
@@ -221,16 +236,13 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
             }
         };
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> allDisksOkBuilder;
-        allDisksOkBuilder = ImmutableOpenMap.builder();
-        allDisksOkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 50));
-        allDisksOkBuilder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 50));
-        final ImmutableOpenMap<String, DiskUsage> allDisksOk = allDisksOkBuilder.build();
+        final Map<String, DiskUsage> allDisksOk = new HashMap<>();
+        allDisksOk.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 50));
+        allDisksOk.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 50));
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> oneDiskAboveWatermarkBuilder = ImmutableOpenMap.builder();
-        oneDiskAboveWatermarkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 9)));
-        oneDiskAboveWatermarkBuilder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 50));
-        final ImmutableOpenMap<String, DiskUsage> oneDiskAboveWatermark = oneDiskAboveWatermarkBuilder.build();
+        final Map<String, DiskUsage> oneDiskAboveWatermark = new HashMap<>();
+        oneDiskAboveWatermark.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 9)));
+        oneDiskAboveWatermark.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 50));
 
         // should not reroute when all disks are ok
         currentTime.addAndGet(randomLongBetween(0, 120000));
@@ -297,12 +309,11 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
         assertNull(listenerReference.get());
 
         // should reroute again when one disk has reserved space that pushes it over the high watermark
-        final ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> builder = ImmutableOpenMap.builder(1);
-        builder.put(
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpaces = new HashMap<>(1);
+        reservedSpaces.put(
             new ClusterInfo.NodeAndPath("node1", "/foo/bar"),
             new ClusterInfo.ReservedSpace.Builder().add(new ShardId("baz", "quux", 0), between(41, 100)).build()
         );
-        final ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpaces = builder.build();
 
         currentTime.addAndGet(
             randomLongBetween(
@@ -313,7 +324,6 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
         monitor.onNewInfo(clusterInfo(allDisksOk, reservedSpaces));
         assertNotNull(listenerReference.get());
         listenerReference.getAndSet(null).onResponse(null);
-
     }
 
     public void testAutoReleaseIndices() {
@@ -337,19 +347,17 @@ public void testAutoReleaseIndices() {
         );
         assertThat(clusterState.getRoutingTable().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(8));
 
-        final ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpacesBuilder = ImmutableOpenMap
-            .builder();
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpaces = new HashMap<>();
         final int reservedSpaceNode1 = between(0, 10);
-        reservedSpacesBuilder.put(
+        reservedSpaces.put(
             new ClusterInfo.NodeAndPath("node1", "/foo/bar"),
             new ClusterInfo.ReservedSpace.Builder().add(new ShardId("", "", 0), reservedSpaceNode1).build()
         );
         final int reservedSpaceNode2 = between(0, 10);
-        reservedSpacesBuilder.put(
+        reservedSpaces.put(
             new ClusterInfo.NodeAndPath("node2", "/foo/bar"),
             new ClusterInfo.ReservedSpace.Builder().add(new ShardId("", "", 0), reservedSpaceNode2).build()
         );
-        ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpaces = reservedSpacesBuilder.build();
 
         DiskThresholdMonitor monitor = new DiskThresholdMonitor(
             Settings.EMPTY,
@@ -372,23 +380,29 @@ protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener
                 }
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
+
         };
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        ImmutableOpenMap.Builder<String, DiskUsage> builder = ImmutableOpenMap.builder();
+        Map<String, DiskUsage> builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 4)));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, between(0, 4)));
-        monitor.onNewInfo(clusterInfo(builder.build(), reservedSpaces));
+        monitor.onNewInfo(clusterInfo(builder, reservedSpaces));
         assertEquals(new HashSet<>(Arrays.asList("test_1", "test_2")), indicesToMarkReadOnly.get());
         assertNull(indicesToRelease.get());
 
         // Reserved space is ignored when applying block
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 90)));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, between(5, 90)));
-        monitor.onNewInfo(clusterInfo(builder.build(), reservedSpaces));
+        monitor.onNewInfo(clusterInfo(builder, reservedSpaces));
         assertNull(indicesToMarkReadOnly.get());
         assertNull(indicesToRelease.get());
 
@@ -428,70 +442,75 @@ protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener
                 }
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
         // When free disk on any of node1 or node2 goes below 5% flood watermark, then apply index block on indices not having the block
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 100)));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, between(0, 4)));
-        monitor.onNewInfo(clusterInfo(builder.build(), reservedSpaces));
+        monitor.onNewInfo(clusterInfo(builder, reservedSpaces));
         assertThat(indicesToMarkReadOnly.get(), contains("test_1"));
         assertNull(indicesToRelease.get());
 
         // When free disk on node1 and node2 goes above 10% high watermark then release index block, ignoring reserved space
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(10, 100)));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, between(10, 100)));
-        monitor.onNewInfo(clusterInfo(builder.build(), reservedSpaces));
+        monitor.onNewInfo(clusterInfo(builder, reservedSpaces));
         assertNull(indicesToMarkReadOnly.get());
         assertThat(indicesToRelease.get(), contains("test_2"));
 
         // When no usage information is present for node2, we don't release the block
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 4)));
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertThat(indicesToMarkReadOnly.get(), contains("test_1"));
         assertNull(indicesToRelease.get());
 
         // When disk usage on one node is between the high and flood-stage watermarks, nothing changes
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 9)));
         builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, between(5, 100)));
         if (randomBoolean()) {
             builder.put("node3", new DiskUsage("node3", "node3", "/foo/bar", 100, between(0, 100)));
         }
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertNull(indicesToMarkReadOnly.get());
         assertNull(indicesToRelease.get());
 
         // When disk usage on one node is missing and the other is below the high watermark, nothing changes
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 100)));
         if (randomBoolean()) {
             builder.put("node3", new DiskUsage("node3", "node3", "/foo/bar", 100, between(0, 100)));
         }
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertNull(indicesToMarkReadOnly.get());
         assertNull(indicesToRelease.get());
 
         // When disk usage on one node is missing and the other is above the flood-stage watermark, affected indices are blocked
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
-        builder = ImmutableOpenMap.builder();
+        builder = new HashMap<>();
         builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 4)));
         if (randomBoolean()) {
             builder.put("node3", new DiskUsage("node3", "node3", "/foo/bar", 100, between(0, 100)));
         }
-        monitor.onNewInfo(clusterInfo(builder.build()));
+        monitor.onNewInfo(clusterInfo(builder));
         assertThat(indicesToMarkReadOnly.get(), contains("test_1"));
         assertNull(indicesToRelease.get());
     }
@@ -536,24 +555,25 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
             long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, ClusterInfo info, ClusterState reroutedClusterState) {
                 return relocatingShardSizeRef.get();
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> allDisksOkBuilder;
-        allDisksOkBuilder = ImmutableOpenMap.builder();
-        allDisksOkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(15, 100)));
-        final ImmutableOpenMap<String, DiskUsage> allDisksOk = allDisksOkBuilder.build();
+        final Map<String, DiskUsage> allDisksOk;
+        allDisksOk = new HashMap<>();
+        allDisksOk.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(15, 100)));
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> aboveLowWatermarkBuilder = ImmutableOpenMap.builder();
-        aboveLowWatermarkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(10, 14)));
-        final ImmutableOpenMap<String, DiskUsage> aboveLowWatermark = aboveLowWatermarkBuilder.build();
+        final Map<String, DiskUsage> aboveLowWatermark = new HashMap<>();
+        aboveLowWatermark.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(10, 14)));
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> aboveHighWatermarkBuilder = ImmutableOpenMap.builder();
-        aboveHighWatermarkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 9)));
-        final ImmutableOpenMap<String, DiskUsage> aboveHighWatermark = aboveHighWatermarkBuilder.build();
+        final Map<String, DiskUsage> aboveHighWatermark = new HashMap<>();
+        aboveHighWatermark.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(5, 9)));
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> aboveFloodStageWatermarkBuilder = ImmutableOpenMap.builder();
-        aboveFloodStageWatermarkBuilder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 4)));
-        final ImmutableOpenMap<String, DiskUsage> aboveFloodStageWatermark = aboveFloodStageWatermarkBuilder.build();
+        final Map<String, DiskUsage> aboveFloodStageWatermark = new HashMap<>();
+        aboveFloodStageWatermark.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, between(0, 4)));
 
         assertNoLogging(monitor, allDisksOk);
 
@@ -564,12 +584,16 @@ long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, Cluste
         );
 
         advanceTime.set(false); // will do one reroute and emit warnings, but subsequent reroutes and associated messages are delayed
-        assertSingleWarningMessage(
-            monitor,
-            aboveHighWatermark,
+        final List<String> messages = new ArrayList<>();
+        messages.add(
             "high disk watermark [90%] exceeded on * shards will be relocated away from this node* "
                 + "the node is expected to continue to exceed the high disk watermark when these relocations are complete"
         );
+        messages.add(
+            "Putting index create block on cluster as all nodes are breaching high disk watermark. "
+                + "Number of nodes above high watermark: 1."
+        );
+        assertMultipleWarningMessages(monitor, aboveHighWatermark, messages);
 
         advanceTime.set(true);
         assertRepeatedWarningMessages(
@@ -588,22 +612,11 @@ long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, Cluste
 
         relocatingShardSizeRef.set(-5L);
         advanceTime.set(true);
-        assertSingleInfoMessage(
-            monitor,
-            aboveHighWatermark,
-            "high disk watermark [90%] exceeded on * shards will be relocated away from this node* "
-                + "the node is expected to be below the high disk watermark when these relocations are complete"
-        );
 
         relocatingShardSizeRef.set(0L);
         timeSupplier.getAsLong(); // advance time long enough to do another reroute
         advanceTime.set(false); // will do one reroute and emit warnings, but subsequent reroutes and associated messages are delayed
-        assertSingleWarningMessage(
-            monitor,
-            aboveHighWatermark,
-            "high disk watermark [90%] exceeded on * shards will be relocated away from this node* "
-                + "the node is expected to continue to exceed the high disk watermark when these relocations are complete"
-        );
+        assertMultipleWarningMessages(monitor, aboveHighWatermark, messages);
 
         advanceTime.set(true);
         assertRepeatedWarningMessages(
@@ -655,8 +668,164 @@ long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, Cluste
         );
     }
 
-    private void assertNoLogging(DiskThresholdMonitor monitor, ImmutableOpenMap<String, DiskUsage> diskUsages)
-        throws IllegalAccessException {
+    public void testIndexCreateBlockWhenNoDataNodeHealthy() {
+        AllocationService allocation = createAllocationService(
+            Settings.builder().put("cluster.routing.allocation.node_concurrent_recoveries", 10).build()
+        );
+        Metadata metadata = Metadata.builder().build();
+        RoutingTable routingTable = RoutingTable.builder().build();
+        final ClusterState clusterState = applyStartedShardsUntilNoChange(
+            ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build(),
+            allocation
+        );
+        AtomicInteger countBlocksCalled = new AtomicInteger();
+        AtomicBoolean reroute = new AtomicBoolean(false);
+        AtomicReference<Set<String>> indices = new AtomicReference<>();
+        AtomicLong currentTime = new AtomicLong();
+        Settings settings = Settings.builder().build();
+        DiskThresholdMonitor monitor = new DiskThresholdMonitor(
+            settings,
+            () -> clusterState,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            null,
+            currentTime::get,
+            (reason, priority, listener) -> {
+                assertTrue(reroute.compareAndSet(false, true));
+                assertThat(priority, equalTo(Priority.HIGH));
+                listener.onResponse(null);
+            }
+        ) {
+
+            @Override
+            protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionListener<Void> listener, boolean readOnly) {
+                assertTrue(indices.compareAndSet(null, indicesToMarkReadOnly));
+                assertFalse(readOnly);
+                listener.onResponse(null);
+            }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                countBlocksCalled.set(countBlocksCalled.get() + 1);
+                listener.onResponse(null);
+            }
+        };
+
+        final Map<String, DiskUsage> builder = new HashMap<>();
+        monitor.onNewInfo(clusterInfo(builder));
+        assertTrue(countBlocksCalled.get() == 0);
+    }
+
+    public void testIndexCreateBlockRemovedOnlyWhenAnyNodeAboveHighWatermark() {
+        AllocationService allocation = createAllocationService(
+            Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.blocks.create_index.enabled", false)
+                .build()
+        );
+        Metadata metadata = Metadata.builder()
+            .put(
+                IndexMetadata.builder("test")
+                    .settings(settings(Version.CURRENT).put("index.routing.allocation.require._id", "node2"))
+                    .numberOfShards(1)
+                    .numberOfReplicas(0)
+            )
+            .put(
+                IndexMetadata.builder("test_1")
+                    .settings(settings(Version.CURRENT).put("index.routing.allocation.require._id", "node1"))
+                    .numberOfShards(1)
+                    .numberOfReplicas(0)
+            )
+            .put(
+                IndexMetadata.builder("test_2")
+                    .settings(settings(Version.CURRENT).put("index.routing.allocation.require._id", "node1"))
+                    .numberOfShards(1)
+                    .numberOfReplicas(0)
+            )
+            .build();
+        RoutingTable routingTable = RoutingTable.builder()
+            .addAsNew(metadata.index("test"))
+            .addAsNew(metadata.index("test_1"))
+            .addAsNew(metadata.index("test_2"))
+            .build();
+
+        final ClusterState clusterState = applyStartedShardsUntilNoChange(
+            ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .blocks(ClusterBlocks.builder().addGlobalBlock(Metadata.CLUSTER_CREATE_INDEX_BLOCK).build())
+                .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")))
+                .build(),
+            allocation
+        );
+        AtomicReference<Set<String>> indices = new AtomicReference<>();
+        AtomicInteger countBlocksCalled = new AtomicInteger();
+        AtomicInteger countUnblockBlocksCalled = new AtomicInteger();
+        AtomicLong currentTime = new AtomicLong();
+        Settings settings = Settings.builder().put(CLUSTER_CREATE_INDEX_BLOCK_AUTO_RELEASE.getKey(), true).build();
+        DiskThresholdMonitor monitor = new DiskThresholdMonitor(
+            settings,
+            () -> clusterState,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            null,
+            currentTime::get,
+            (reason, priority, listener) -> {
+                listener.onResponse(null);
+            }
+        ) {
+
+            @Override
+            protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionListener<Void> listener, boolean readOnly) {
+                assertTrue(indices.compareAndSet(null, indicesToMarkReadOnly));
+                assertTrue(readOnly);
+                listener.onResponse(null);
+            }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                if (indexCreateBlock == true) {
+                    countBlocksCalled.set(countBlocksCalled.get() + 1);
+                } else {
+                    countUnblockBlocksCalled.set(countUnblockBlocksCalled.get() + 1);
+                }
+
+                listener.onResponse(null);
+            }
+        };
+
+        Map<String, DiskUsage> builder = new HashMap<>();
+
+        // Initially all the nodes are breaching high watermark and IndexCreateBlock is already present on the cluster.
+        // Since block is already present, DiskThresholdMonitor should not again try to apply block.
+        builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 9));
+        builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 9));
+        monitor.onNewInfo(clusterInfo(builder));
+        // Since Block is already present and nodes are below high watermark so neither block nor unblock will be called.
+        assertEquals(countBlocksCalled.get(), 0);
+        assertEquals(countUnblockBlocksCalled.get(), 0);
+
+        // Ensure DiskThresholdMonitor does not try to remove block in the next iteration if all nodes are breaching high watermark.
+        monitor.onNewInfo(clusterInfo(builder));
+        assertEquals(countBlocksCalled.get(), 0);
+        assertEquals(countUnblockBlocksCalled.get(), 0);
+
+        builder = new HashMap<>();
+
+        // If any node is no longer breaching high watermark, DiskThresholdMonitor should remove IndexCreateBlock.
+        builder.put("node1", new DiskUsage("node1", "node1", "/foo/bar", 100, 19));
+        builder.put("node2", new DiskUsage("node2", "node2", "/foo/bar", 100, 1));
+        // Need to add delay in current time to allow nodes to be removed high watermark list.
+        currentTime.addAndGet(randomLongBetween(60001, 120000));
+
+        monitor.onNewInfo(clusterInfo(builder));
+        // Block will be removed if any nodes is no longer breaching high watermark.
+        assertEquals(countBlocksCalled.get(), 0);
+        assertEquals(countUnblockBlocksCalled.get(), 1);
+    }
+
+    private void assertNoLogging(DiskThresholdMonitor monitor, final Map<String, DiskUsage> diskUsages) throws IllegalAccessException {
         try (MockLogAppender mockAppender = MockLogAppender.createForLoggers(LogManager.getLogger(DiskThresholdMonitor.class))) {
             mockAppender.addExpectation(
                 new MockLogAppender.UnseenEventExpectation(
@@ -683,26 +852,27 @@ private void assertNoLogging(DiskThresholdMonitor monitor, ImmutableOpenMap<Stri
         }
     }
 
-    private void assertRepeatedWarningMessages(DiskThresholdMonitor monitor, ImmutableOpenMap<String, DiskUsage> diskUsages, String message)
+    private void assertRepeatedWarningMessages(DiskThresholdMonitor monitor, final Map<String, DiskUsage> diskUsages, String message)
         throws IllegalAccessException {
         for (int i = between(1, 3); i >= 0; i--) {
             assertLogging(monitor, diskUsages, Level.WARN, message);
         }
     }
 
-    private void assertSingleWarningMessage(DiskThresholdMonitor monitor, ImmutableOpenMap<String, DiskUsage> diskUsages, String message)
+    private void assertMultipleWarningMessages(DiskThresholdMonitor monitor, final Map<String, DiskUsage> diskUsages, List<String> messages)
         throws IllegalAccessException {
-        assertLogging(monitor, diskUsages, Level.WARN, message);
-        assertNoLogging(monitor, diskUsages);
+        for (int index = 0; index < messages.size(); index++) {
+            assertLogging(monitor, diskUsages, Level.WARN, messages.get(index));
+        }
     }
 
-    private void assertSingleInfoMessage(DiskThresholdMonitor monitor, ImmutableOpenMap<String, DiskUsage> diskUsages, String message)
+    private void assertSingleInfoMessage(DiskThresholdMonitor monitor, final Map<String, DiskUsage> diskUsages, String message)
         throws IllegalAccessException {
         assertLogging(monitor, diskUsages, Level.INFO, message);
         assertNoLogging(monitor, diskUsages);
     }
 
-    private void assertLogging(DiskThresholdMonitor monitor, ImmutableOpenMap<String, DiskUsage> diskUsages, Level level, String message)
+    private void assertLogging(DiskThresholdMonitor monitor, final Map<String, DiskUsage> diskUsages, Level level, String message)
         throws IllegalAccessException {
         try (MockLogAppender mockAppender = MockLogAppender.createForLoggers(LogManager.getLogger(DiskThresholdMonitor.class))) {
             mockAppender.start();
@@ -724,15 +894,15 @@ private void assertLogging(DiskThresholdMonitor monitor, ImmutableOpenMap<String
         }
     }
 
-    private static ClusterInfo clusterInfo(ImmutableOpenMap<String, DiskUsage> diskUsages) {
-        return clusterInfo(diskUsages, ImmutableOpenMap.of());
+    private static ClusterInfo clusterInfo(final Map<String, DiskUsage> diskUsages) {
+        return clusterInfo(diskUsages, Map.of());
     }
 
     private static ClusterInfo clusterInfo(
-        ImmutableOpenMap<String, DiskUsage> diskUsages,
-        ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
+        final Map<String, DiskUsage> diskUsages,
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
     ) {
-        return new ClusterInfo(diskUsages, null, null, null, reservedSpace);
+        return new ClusterInfo(diskUsages, null, null, null, reservedSpace, Map.of());
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettingsTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettingsTests.java
index 363484777fe66..775345efb668c 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettingsTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdSettingsTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Locale;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedNodeRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedNodeRoutingTests.java
index f60497b4108b7..02188ba116c46 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedNodeRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedNodeRoutingTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
@@ -54,6 +53,7 @@
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.indices.cluster.ClusterStateChanges;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -70,6 +70,7 @@
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
 import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.hamcrest.Matchers.equalTo;
@@ -138,7 +139,15 @@ public void testSimpleFailedNodeTest() {
         }
     }
 
+    public void testRandomClusterPromotesOldestReplica() throws InterruptedException {
+        testRandomClusterPromotesReplica(true);
+    }
+
     public void testRandomClusterPromotesNewestReplica() throws InterruptedException {
+        testRandomClusterPromotesReplica(false);
+    }
+
+    void testRandomClusterPromotesReplica(boolean isSegmentReplicationEnabled) throws InterruptedException {
 
         ThreadPool threadPool = new TestThreadPool(getClass().getName());
         ClusterStateChanges cluster = new ClusterStateChanges(xContentRegistry(), threadPool);
@@ -153,9 +162,9 @@ public void testRandomClusterPromotesNewestReplica() throws InterruptedException
         }
 
         // Log the node versions (for debugging if necessary)
-        for (ObjectCursor<DiscoveryNode> cursor : state.nodes().getDataNodes().values()) {
-            Version nodeVer = cursor.value.getVersion();
-            logger.info("--> node [{}] has version [{}]", cursor.value.getId(), nodeVer);
+        for (final DiscoveryNode cursor : state.nodes().getDataNodes().values()) {
+            Version nodeVer = cursor.getVersion();
+            logger.info("--> node [{}] has version [{}]", cursor.getId(), nodeVer);
         }
 
         // randomly create some indices
@@ -165,6 +174,9 @@ public void testRandomClusterPromotesNewestReplica() throws InterruptedException
             Settings.Builder settingsBuilder = Settings.builder()
                 .put(SETTING_NUMBER_OF_SHARDS, randomIntBetween(1, 4))
                 .put(SETTING_NUMBER_OF_REPLICAS, randomIntBetween(2, 4));
+            if (isSegmentReplicationEnabled) {
+                settingsBuilder.put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT);
+            }
             CreateIndexRequest request = new CreateIndexRequest(name, settingsBuilder.build()).waitForActiveShards(ActiveShardCount.NONE);
             state = cluster.createIndex(state, request);
             assertTrue(state.metadata().hasIndex(name));
@@ -188,8 +200,9 @@ public void testRandomClusterPromotesNewestReplica() throws InterruptedException
             // Pick a random subset of primaries to fail
             List<FailedShard> shardsToFail = new ArrayList<>();
             List<ShardRouting> failedPrimaries = randomSubsetOf(primaries);
-            failedPrimaries.stream()
-                .forEach(sr -> { shardsToFail.add(new FailedShard(randomFrom(sr), "failed primary", new Exception(), randomBoolean())); });
+            failedPrimaries.stream().forEach(sr -> {
+                shardsToFail.add(new FailedShard(randomFrom(sr), "failed primary", new Exception(), randomBoolean()));
+            });
 
             logger.info("--> state before failing shards: {}", state);
             state = cluster.applyFailedShards(state, shardsToFail);
@@ -206,13 +219,23 @@ public void testRandomClusterPromotesNewestReplica() throws InterruptedException
                     Version candidateVer = getNodeVersion(sr, compareState);
                     if (candidateVer != null) {
                         logger.info("--> candidate on {} node; shard routing: {}", candidateVer, sr);
-                        assertTrue(
-                            "candidate was not on the newest version, new primary is on "
-                                + newPrimaryVersion
-                                + " and there is a candidate on "
-                                + candidateVer,
-                            candidateVer.onOrBefore(newPrimaryVersion)
-                        );
+                        if (isSegmentReplicationEnabled) {
+                            assertTrue(
+                                "candidate was not on the oldest version, new primary is on "
+                                    + newPrimaryVersion
+                                    + " and there is a candidate on "
+                                    + candidateVer,
+                                candidateVer.onOrAfter(newPrimaryVersion)
+                            );
+                        } else {
+                            assertTrue(
+                                "candidate was not on the newest version, new primary is on "
+                                    + newPrimaryVersion
+                                    + " and there is a candidate on "
+                                    + candidateVer,
+                                candidateVer.onOrBefore(newPrimaryVersion)
+                            );
+                        }
                     }
                 });
             });
@@ -230,7 +253,7 @@ private static Version getNodeVersion(ShardRouting shardRouting, ClusterState st
 
     public ClusterState randomInitialClusterState() {
         List<DiscoveryNode> allNodes = new ArrayList<>();
-        DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the master
+        DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the cluster-manager
         allNodes.add(localNode);
         // at least two nodes that have the data role so that we can allocate shards
         allNodes.add(createNode(DiscoveryNodeRole.DATA_ROLE));
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedShardsRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedShardsRoutingTests.java
index 227d4c38e1838..db4cedbbbe7b5 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedShardsRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/FailedShardsRoutingTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
@@ -49,7 +48,8 @@
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.test.VersionUtils;
 
 import java.util.ArrayList;
@@ -648,10 +648,21 @@ public void testFailAllReplicasInitializingOnPrimaryFailWhileHavingAReplicaToEle
     }
 
     public void testReplicaOnNewestVersionIsPromoted() {
+        testReplicaIsPromoted(false);
+    }
+
+    public void testReplicaOnOldestVersionIsPromoted() {
+        testReplicaIsPromoted(true);
+    }
+
+    private void testReplicaIsPromoted(boolean isSegmentReplicationEnabled) {
         AllocationService allocation = createAllocationService(Settings.builder().build());
 
+        Settings.Builder settingsBuilder = isSegmentReplicationEnabled
+            ? settings(Version.CURRENT).put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            : settings(Version.CURRENT);
         Metadata metadata = Metadata.builder()
-            .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(3))
+            .put(IndexMetadata.builder("test").settings(settingsBuilder).numberOfShards(1).numberOfReplicas(3))
             .build();
 
         RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
@@ -715,7 +726,12 @@ public void testReplicaOnNewestVersionIsPromoted() {
         assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(4));
         assertThat(clusterState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
 
-        ShardRouting startedReplica = clusterState.getRoutingNodes().activeReplicaWithHighestVersion(shardId);
+        ShardRouting startedReplica;
+        if (isSegmentReplicationEnabled) {
+            startedReplica = clusterState.getRoutingNodes().activeReplicaWithOldestVersion(shardId);
+        } else {
+            startedReplica = clusterState.getRoutingNodes().activeReplicaWithHighestVersion(shardId);
+        }
         logger.info("--> all shards allocated, replica that should be promoted: {}", startedReplica);
 
         // fail the primary shard again and make sure the correct replica is promoted
@@ -734,19 +750,30 @@ public void testReplicaOnNewestVersionIsPromoted() {
         assertNotNull(replicaNodeVersion);
         logger.info("--> shard {} got assigned to node with version {}", startedReplica, replicaNodeVersion);
 
-        for (ObjectCursor<DiscoveryNode> cursor : clusterState.nodes().getDataNodes().values()) {
-            if ("node1".equals(cursor.value.getId())) {
+        for (final DiscoveryNode cursor : clusterState.nodes().getDataNodes().values()) {
+            if ("node1".equals(cursor.getId())) {
                 // Skip the node that the primary was on, it doesn't have a replica so doesn't need a version check
                 continue;
             }
-            Version nodeVer = cursor.value.getVersion();
-            assertTrue(
-                "expected node [" + cursor.value.getId() + "] with version " + nodeVer + " to be before " + replicaNodeVersion,
-                replicaNodeVersion.onOrAfter(nodeVer)
-            );
+            Version nodeVer = cursor.getVersion();
+            if (isSegmentReplicationEnabled) {
+                assertTrue(
+                    "expected node [" + cursor.getId() + "] with version " + nodeVer + " to be after " + replicaNodeVersion,
+                    replicaNodeVersion.onOrBefore(nodeVer)
+                );
+            } else {
+                assertTrue(
+                    "expected node [" + cursor.getId() + "] with version " + nodeVer + " to be before " + replicaNodeVersion,
+                    replicaNodeVersion.onOrAfter(nodeVer)
+                );
+            }
         }
 
-        startedReplica = clusterState.getRoutingNodes().activeReplicaWithHighestVersion(shardId);
+        if (isSegmentReplicationEnabled) {
+            startedReplica = clusterState.getRoutingNodes().activeReplicaWithOldestVersion(shardId);
+        } else {
+            startedReplica = clusterState.getRoutingNodes().activeReplicaWithHighestVersion(shardId);
+        }
         logger.info("--> failing primary shard a second time, should select: {}", startedReplica);
 
         // fail the primary shard again, and ensure the same thing happens
@@ -765,17 +792,24 @@ public void testReplicaOnNewestVersionIsPromoted() {
         assertNotNull(replicaNodeVersion);
         logger.info("--> shard {} got assigned to node with version {}", startedReplica, replicaNodeVersion);
 
-        for (ObjectCursor<DiscoveryNode> cursor : clusterState.nodes().getDataNodes().values()) {
-            if (primaryShardToFail.currentNodeId().equals(cursor.value.getId())
-                || secondPrimaryShardToFail.currentNodeId().equals(cursor.value.getId())) {
+        for (final DiscoveryNode cursor : clusterState.nodes().getDataNodes().values()) {
+            if (primaryShardToFail.currentNodeId().equals(cursor.getId())
+                || secondPrimaryShardToFail.currentNodeId().equals(cursor.getId())) {
                 // Skip the node that the primary was on, it doesn't have a replica so doesn't need a version check
                 continue;
             }
-            Version nodeVer = cursor.value.getVersion();
-            assertTrue(
-                "expected node [" + cursor.value.getId() + "] with version " + nodeVer + " to be before " + replicaNodeVersion,
-                replicaNodeVersion.onOrAfter(nodeVer)
-            );
+            Version nodeVer = cursor.getVersion();
+            if (isSegmentReplicationEnabled) {
+                assertTrue(
+                    "expected node [" + cursor.getId() + "] with version " + nodeVer + " to be after " + replicaNodeVersion,
+                    replicaNodeVersion.onOrBefore(nodeVer)
+                );
+            } else {
+                assertTrue(
+                    "expected node [" + cursor.getId() + "] with version " + nodeVer + " to be before " + replicaNodeVersion,
+                    replicaNodeVersion.onOrAfter(nodeVer)
+                );
+            }
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/InSyncAllocationIdTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/InSyncAllocationIdTests.java
index 243701e746ef5..3a1f4a586d519 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/InSyncAllocationIdTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/InSyncAllocationIdTests.java
@@ -170,7 +170,7 @@ public void testInSyncAllocationIdsUpdated() {
 
     /**
      * Assume following scenario: indexing request is written to primary, but fails to be replicated to active replica.
-     * The primary instructs master to fail replica before acknowledging write to client. In the meanwhile, the node of the replica was
+     * The primary instructs cluster-manager to fail replica before acknowledging write to client. In the meanwhile, the node of the replica was
      * removed from the cluster (disassociateDeadNodes). This means that the ShardRouting of the replica was failed, but it's allocation
      * id is still part of the in-sync set. We have to make sure that the failShard request from the primary removes the allocation id
      * from the in-sync set.
@@ -204,8 +204,8 @@ public void testDeadNodesBeforeReplicaFailed() throws Exception {
 
     /**
      * Assume following scenario: indexing request is written to primary, but fails to be replicated to active replica.
-     * The primary instructs master to fail replica before acknowledging write to client. In the meanwhile, primary fails for an unrelated
-     * reason. Master now batches both requests to fail primary and replica. We have to make sure that only the allocation id of the primary
+     * The primary instructs cluster-manager to fail replica before acknowledging write to client. In the meanwhile, primary fails for an unrelated
+     * reason. Cluster-manager now batches both requests to fail primary and replica. We have to make sure that only the allocation id of the primary
      * is kept in the in-sync allocation set before we acknowledge request to client. Otherwise we would acknowledge a write that made it
      * into the primary but not the replica but the replica is still considered non-stale.
      */
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/IndexShardConstraintDeciderOverlapTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/IndexShardConstraintDeciderOverlapTests.java
index 773c82be55ead..cf32d2b3cf00f 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/IndexShardConstraintDeciderOverlapTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/IndexShardConstraintDeciderOverlapTests.java
@@ -15,9 +15,8 @@
 import org.opensearch.cluster.OpenSearchAllocationWithConstraintsTestCase;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.VersionUtils;
 
 import java.util.HashMap;
@@ -50,28 +49,22 @@ public void testHighWatermarkBreachWithLowShardCount() {
             .build();
 
         // Build Shard size and disk usages
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node_0", new DiskUsage("node_0", "node_0", "/dev/null", 100, 80)); // 20% used
-        usagesBuilder.put("node_1", new DiskUsage("node_1", "node_1", "/dev/null", 100, 55)); // 45% used
-        usagesBuilder.put("node_2", new DiskUsage("node_2", "node_2", "/dev/null", 100, 35)); // 65% used
-        usagesBuilder.put("high_watermark_node_0", new DiskUsage("high_watermark_node_0", "high_watermark_node_0", "/dev/null", 100, 10)); // 90%
-                                                                                                                                           // used
-
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        clusterState.getRoutingTable().allShards().forEach(shard -> shardSizesBuilder.put(shardIdentifierFromRouting(shard), 1L)); // Each
-                                                                                                                                   // shard
-                                                                                                                                   // is 1
-                                                                                                                                   // byte
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
-
-        final ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace = new ImmutableOpenMap.Builder<
-            ClusterInfo.NodeAndPath,
-            ClusterInfo.ReservedSpace>().fPut(getNodeAndDevNullPath("node_0"), getReservedSpace())
-                .fPut(getNodeAndDevNullPath("node_1"), getReservedSpace())
-                .fPut(getNodeAndDevNullPath("node_2"), getReservedSpace())
-                .fPut(getNodeAndDevNullPath("high_watermark_node_0"), getReservedSpace())
-                .build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node_0", new DiskUsage("node_0", "node_0", "/dev/null", 100, 80)); // 20% used
+        usages.put("node_1", new DiskUsage("node_1", "node_1", "/dev/null", 100, 55)); // 45% used
+        usages.put("node_2", new DiskUsage("node_2", "node_2", "/dev/null", 100, 35)); // 65% used
+        usages.put("high_watermark_node_0", new DiskUsage("high_watermark_node_0", "high_watermark_node_0", "/dev/null", 100, 10)); // 90%
+                                                                                                                                    // used
+        final Map<String, Long> shardSizes = new HashMap<>();
+        clusterState.getRoutingTable().allShards().forEach(shard -> shardSizes.put(shardIdentifierFromRouting(shard), 1L)); // Each
+                                                                                                                            // shard
+                                                                                                                            // is 1
+                                                                                                                            // byte
+        final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace = new HashMap<>();
+        reservedSpace.put(getNodeAndDevNullPath("node_0"), getReservedSpace());
+        reservedSpace.put(getNodeAndDevNullPath("node_1"), getReservedSpace());
+        reservedSpace.put(getNodeAndDevNullPath("node_2"), getReservedSpace());
+        reservedSpace.put(getNodeAndDevNullPath("high_watermark_node_0"), getReservedSpace());
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes, reservedSpace);
         ClusterInfoService cis = () -> clusterInfo;
         allocation = createAllocationService(settings, cis);
@@ -84,10 +77,9 @@ public void testHighWatermarkBreachWithLowShardCount() {
         /* Shard sizes that would breach high watermark on node_2 if allocated.
          */
         addIndices("big_index_", 1, 10, 0);
-        ImmutableOpenMap.Builder<String, Long> bigIndexShardSizeBuilder = ImmutableOpenMap.builder(shardSizes);
-        clusterState.getRoutingNodes().unassigned().forEach(shard -> bigIndexShardSizeBuilder.put(shardIdentifierFromRouting(shard), 20L));
-        shardSizes = bigIndexShardSizeBuilder.build();
-        final ClusterInfo bigIndexClusterInfo = new DevNullClusterInfo(usages, usages, shardSizes, reservedSpace);
+        final Map<String, Long> bigIndexShardSizes = new HashMap<>(shardSizes);
+        clusterState.getRoutingNodes().unassigned().forEach(shard -> bigIndexShardSizes.put(shardIdentifierFromRouting(shard), 20L));
+        final ClusterInfo bigIndexClusterInfo = new DevNullClusterInfo(usages, usages, bigIndexShardSizes, reservedSpace);
         cis = () -> bigIndexClusterInfo;
         allocation = createAllocationService(settings, cis);
 
@@ -179,12 +171,12 @@ public void testZoneUnbalanced() {
      */
     public static class DevNullClusterInfo extends ClusterInfo {
         public DevNullClusterInfo(
-            ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage,
-            ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsage,
-            ImmutableOpenMap<String, Long> shardSizes,
-            ImmutableOpenMap<NodeAndPath, ReservedSpace> reservedSpace
+            final Map<String, DiskUsage> leastAvailableSpaceUsage,
+            final Map<String, DiskUsage> mostAvailableSpaceUsage,
+            final Map<String, Long> shardSizes,
+            final Map<NodeAndPath, ReservedSpace> reservedSpace
         ) {
-            super(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, null, reservedSpace);
+            super(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, null, reservedSpace, Map.of());
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/MaxRetryAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/MaxRetryAllocationDeciderTests.java
index 440471b787e8c..669a8a5da295e 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/MaxRetryAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/MaxRetryAllocationDeciderTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeLoadAwareAllocationTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeLoadAwareAllocationTests.java
index d2e7e0e7e636a..5f7964e6666e4 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeLoadAwareAllocationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeLoadAwareAllocationTests.java
@@ -22,21 +22,21 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.UnassignedInfo;
-import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.NodeLoadAwareAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 
+import java.util.List;
 import java.util.Map;
 
 import static java.util.Collections.singletonMap;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.sameInstance;
 import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.opensearch.cluster.routing.ShardRoutingState.UNASSIGNED;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.sameInstance;
 
 public class NodeLoadAwareAllocationTests extends OpenSearchAllocationTestCase {
 
@@ -44,7 +44,7 @@ public class NodeLoadAwareAllocationTests extends OpenSearchAllocationTestCase {
 
     public void testNewUnassignedPrimaryAllocationOnOverload() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -106,9 +106,11 @@ public void testNewUnassignedPrimaryAllocationOnOverload() {
             .nodes(DiscoveryNodes.builder(newState.nodes()).add(newNode("node1", singletonMap("zone", "zone_1"))))
             .build();
 
-        // 4 existing shards from this node's local store get started
+        // 4 existing shards from this node's local store get started and cluster rebalances
         newState = strategy.reroute(newState, "reroute");
-        newState = startInitializingShardsAndReroute(strategy, newState);
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
         assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(32));
 
         // add back node2 when skewness is still breached
@@ -135,7 +137,7 @@ public void testNewUnassignedPrimaryAllocationOnOverload() {
 
     public void testNoAllocationLimitsOnOverloadForDisabledLoadFactor() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -230,7 +232,7 @@ public void testNoAllocationLimitsOnOverloadForDisabledLoadFactor() {
     public void testExistingPrimariesAllocationOnOverload() {
         GatewayAllocator gatewayAllocator = new TestGatewayAllocator();
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -282,11 +284,14 @@ public void testExistingPrimariesAllocationOnOverload() {
         newState = ClusterState.builder(newState).metadata(metadata).routingTable(updatedRoutingTable).build();
         newState = strategy.reroute(newState, "reroute");
 
-        newState = startInitializingShardsAndReroute(strategy, newState);
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
 
+        // 28 shards should be assigned (14 on each node -> 8 * 1.5 + 2)
         logger.info("limits should be applied on newly create primaries");
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(24));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(16));
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(28));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(12));
 
         assertEquals(
             12L,
@@ -298,7 +303,7 @@ public void testExistingPrimariesAllocationOnOverload() {
         );
 
         assertEquals(
-            4L,
+            0L,
             newState.getRoutingNodes()
                 .shardsWithState(UNASSIGNED)
                 .stream()
@@ -306,14 +311,14 @@ public void testExistingPrimariesAllocationOnOverload() {
                 .count()
         );
 
-        assertThat(newState.getRoutingNodes().node("node4").size(), equalTo(12));
+        assertThat(newState.getRoutingNodes().node("node4").size(), equalTo(14));
 
         logger.info("--> Remove node4 from zone holding primaries");
         newState = removeNodes(newState, strategy, "node4");
 
         logger.info("--> change the overload load factor to zero and verify if unassigned primaries on disk get assigned despite overload");
         strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -339,10 +344,10 @@ public void testExistingPrimariesAllocationOnOverload() {
         logger.info("--> do another reroute, make sure nothing moves");
         assertThat(strategy.reroute(newState, "reroute").routingTable(), sameInstance(newState.routingTable()));
 
-        assertThat(newState.getRoutingNodes().node("node4").size(), equalTo(12));
-        assertThat(newState.getRoutingNodes().node("node5").size(), equalTo(12));
+        assertThat(newState.getRoutingNodes().node("node4").size(), equalTo(14));
+        assertThat(newState.getRoutingNodes().node("node5").size(), equalTo(14));
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(24));
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(28));
 
         newState = ClusterState.builder(newState)
             .nodes(DiscoveryNodes.builder(newState.nodes()).add(newNode("node1", singletonMap("zone", "zone_1"))))
@@ -379,7 +384,7 @@ public void testExistingPrimariesAllocationOnOverload() {
     public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
         GatewayAllocator gatewayAllocator = new TestGatewayAllocator();
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -436,7 +441,8 @@ public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(30));
+        // Each node can take 12 shards each (2 + ceil(8*1.2))
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(36));
 
         for (ShardRouting shard : newState.getRoutingNodes().shardsWithState(UNASSIGNED)) {
             assertEquals(shard.unassignedInfo().getReason(), UnassignedInfo.Reason.NODE_LEFT);
@@ -458,10 +464,12 @@ public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
         newState = ClusterState.builder(newState).metadata(metadata).routingTable(updatedRoutingTable).build();
         newState = strategy.reroute(newState, "reroute");
 
-        newState = startInitializingShardsAndReroute(strategy, newState);
+        while (!newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty()) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(60));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(20));
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(66));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(14));
 
         logger.info("add another index with 60 shards");
         metadata = Metadata.builder(newState.metadata())
@@ -482,12 +490,12 @@ public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(120));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(20));
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(126));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(14));
 
         logger.info("change settings to allow unassigned primaries");
         strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -499,7 +507,7 @@ public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
         );
 
         for (RoutingNode node : newState.getRoutingNodes()) {
-            assertThat(node.size(), equalTo(40));
+            assertThat(node.size(), equalTo(42));
         }
 
         logger.info("add another index with 5 shards");
@@ -513,21 +521,21 @@ public void testSingleZoneOneReplicaLimitsShardAllocationOnOverload() {
             )
             .build();
         updatedRoutingTable = RoutingTable.builder(newState.routingTable()).addAsNew(metadata.index("test3")).build();
-        // increases avg shard per node to 145/5 = 29, overload factor 1.2, total allowed 35 per node and NO primaries get assigned
-        // since total owning shards are 40 per node already
+        // increases avg shard per node to 145/5 = 29, overload factor 1.2, total allowed 35+2=37 per node and NO primaries get assigned
+        // since total owning shards are 42 per node already
         newState = ClusterState.builder(newState).metadata(metadata).routingTable(updatedRoutingTable).build();
         newState = strategy.reroute(newState, "reroute");
 
         newState = startInitializingShardsAndReroute(strategy, newState);
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(120));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(25));
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(126));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(19));
         assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).stream().filter(ShardRouting::primary).count(), equalTo(5L));
     }
 
     public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverload() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 15,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -600,21 +608,24 @@ public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverload() {
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
 
-        assertThat(newState.getRoutingNodes().node("node14").size(), equalTo(5));
-        assertThat(newState.getRoutingNodes().node("node15").size(), equalTo(5));
+        assertThat(newState.getRoutingNodes().node("node14").size(), equalTo(7));
+        assertThat(newState.getRoutingNodes().node("node15").size(), equalTo(7));
 
         // add the removed node
         newState = addNodes(newState, strategy, "zone3", "node11");
 
-        assertThat(newState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(5));
-        newState = startInitializingShardsAndReroute(strategy, newState);
-        assertThat(newState.getRoutingNodes().node("node11").size(), equalTo(5));
+        assertThat(newState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(6));
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(60));
 
         // add the removed node
         newState = addNodes(newState, strategy, "zone3", "node12");
 
-        assertThat(newState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(5));
-        newState = startInitializingShardsAndReroute(strategy, newState);
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
         assertThat(newState.getRoutingNodes().node("node12").size(), equalTo(5));
 
         // add the removed node
@@ -633,7 +644,7 @@ public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverload() {
 
     public void testThreeZoneOneReplicaLimitsShardAllocationOnOverload() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 15,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -674,13 +685,14 @@ public void testThreeZoneOneReplicaLimitsShardAllocationOnOverload() {
         logger.info("--> add five new node in new zone and reroute");
         clusterState = addNodes(clusterState, strategy, "zone2", "node6", "node7", "node8", "node9", "node10");
 
+        // Each node can take 7 shards each now (2 + ceil(4*1.2))
         assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(30));
-        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(25));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(30));
 
         logger.info("--> complete relocation");
         clusterState = startInitializingShardsAndReroute(strategy, clusterState);
 
-        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(55));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(60));
 
         logger.info("--> do another reroute, make sure nothing moves");
         assertThat(strategy.reroute(clusterState, "reroute").routingTable(), sameInstance(clusterState.routingTable()));
@@ -707,6 +719,7 @@ public void testThreeZoneOneReplicaLimitsShardAllocationOnOverload() {
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
 
+        // Each node can now have 5 shards each
         assertThat(newState.getRoutingNodes().node("node14").size(), equalTo(5));
         assertThat(newState.getRoutingNodes().node("node15").size(), equalTo(5));
 
@@ -726,7 +739,7 @@ public void testThreeZoneOneReplicaLimitsShardAllocationOnOverload() {
 
     public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverloadAcrossZones() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 9,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -791,8 +804,9 @@ public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverloadAcrossZones()
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
         // ensure minority zone doesn't get overloaded
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(53));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(10));
+        // each node can take 10 shards each (2 + ceil(7*1.1))
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(61));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(2));
         for (ShardRouting shard : newState.getRoutingNodes().shardsWithState(UNASSIGNED)) {
             assertEquals(shard.unassignedInfo().getReason(), UnassignedInfo.Reason.NODE_LEFT);
         }
@@ -819,7 +833,7 @@ public void testThreeZoneTwoReplicaLimitsShardAllocationOnOverloadAcrossZones()
 
     public void testSingleZoneTwoReplicaLimitsReplicaAllocationOnOverload() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 3,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -880,7 +894,7 @@ public void testSingleZoneTwoReplicaLimitsReplicaAllocationOnOverload() {
 
     public void testSingleZoneOneReplicaLimitsReplicaAllocationOnOverload() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 5,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -912,15 +926,20 @@ public void testSingleZoneOneReplicaLimitsReplicaAllocationOnOverload() {
         clusterState = startInitializingShardsAndReroute(strategy, clusterState);
 
         assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(20));
-        // assert replicas are not assigned but primaries are
-        logger.info("--> replicas are not initializing");
-        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(0));
+        // Each node can take 11 shards each (2 + ceil(8*1.1)), hence 2 replicas will also start
+        logger.info("--> 2 replicas are initializing");
+        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(2));
 
         for (ShardRouting shard : clusterState.getRoutingNodes().shardsWithState(UNASSIGNED)) {
             assertEquals(shard.unassignedInfo().getReason(), UnassignedInfo.Reason.INDEX_CREATED);
             assertFalse(shard.primary());
         }
 
+        logger.info("--> start the shards (replicas)");
+        while (clusterState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+        }
+
         logger.info("--> do another reroute, make sure nothing moves");
         assertThat(strategy.reroute(clusterState, "reroute").routingTable(), sameInstance(clusterState.routingTable()));
 
@@ -929,10 +948,12 @@ public void testSingleZoneOneReplicaLimitsReplicaAllocationOnOverload() {
 
         assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(18));
 
-        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+        while (clusterState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+        }
 
         logger.info("--> replicas are started");
-        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(38));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(40));
 
         for (ShardRouting shard : clusterState.getRoutingNodes().shardsWithState(UNASSIGNED)) {
             assertEquals(shard.unassignedInfo().getReason(), UnassignedInfo.Reason.INDEX_CREATED);
@@ -956,7 +977,7 @@ public void testSingleZoneOneReplicaLimitsReplicaAllocationOnOverload() {
 
     public void testThreeZoneTwoReplicaLimitsReplicaAllocationUnderFullZoneFailure() {
         AllocationService strategy = createAllocationServiceWithAdditionalSettings(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
                 15,
                 NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
@@ -1012,11 +1033,12 @@ public void testThreeZoneTwoReplicaLimitsReplicaAllocationUnderFullZoneFailure()
             newState = startInitializingShardsAndReroute(strategy, newState);
         }
 
-        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(50));
-        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(10));
+        // Each node can take 7 shards max ( 2 + ceil(4*1.2))
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(60));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
 
         for (RoutingNode node : newState.getRoutingNodes()) {
-            assertThat(node.size(), equalTo(5));
+            assertThat(node.size(), equalTo(6));
         }
 
         // add the removed node
@@ -1025,9 +1047,7 @@ public void testThreeZoneTwoReplicaLimitsReplicaAllocationUnderFullZoneFailure()
             .build();
         newState = strategy.reroute(newState, "reroute");
 
-        assertThat(newState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(5));
         newState = startInitializingShardsAndReroute(strategy, newState);
-        assertThat(newState.getRoutingNodes().node("node11").size(), equalTo(5));
 
         // add the removed node
         newState = ClusterState.builder(newState)
@@ -1035,9 +1055,7 @@ public void testThreeZoneTwoReplicaLimitsReplicaAllocationUnderFullZoneFailure()
             .build();
         newState = strategy.reroute(newState, "reroute");
 
-        assertThat(newState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(5));
         newState = startInitializingShardsAndReroute(strategy, newState);
-        assertThat(newState.getRoutingNodes().node("node12").size(), equalTo(5));
 
         // add the removed node
         newState = ClusterState.builder(newState)
@@ -1068,15 +1086,129 @@ public void testThreeZoneTwoReplicaLimitsReplicaAllocationUnderFullZoneFailure()
         assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
     }
 
+    public void testThreeZoneOneReplicaWithSkewFactorZeroAllShardsAssignedAfterRecovery() {
+        AllocationService strategy = createAllocationServiceWithAdditionalSettings(
+            Map.of(
+                NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_PROVISIONED_CAPACITY_SETTING.getKey(),
+                15,
+                NodeLoadAwareAllocationDecider.CLUSTER_ROUTING_ALLOCATION_LOAD_AWARENESS_SKEW_FACTOR_SETTING.getKey(),
+                0,
+                "cluster.routing.allocation.awareness.force.zone.values",
+                "zone1,zone2,zone3"
+            )
+        );
+
+        logger.info("Building initial routing table for 'testThreeZoneOneReplicaWithSkewFactorZeroAllShardsAssignedAfterRecovery'");
+
+        Metadata metadata = Metadata.builder()
+            .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(30).numberOfReplicas(1))
+            .build();
+
+        RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(initialRoutingTable)
+            .build();
+
+        logger.info("--> adding five nodes on same zone and do rerouting");
+        clusterState = addNodes(clusterState, strategy, "zone1", "node1", "node2", "node3", "node4", "node5");
+        clusterState = strategy.reroute(clusterState, "reroute");
+        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(30));
+
+        logger.info("--> start the shards (primaries)");
+        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+        logger.info("--> add five new node in new zone and reroute");
+        clusterState = addNodes(clusterState, strategy, "zone2", "node6", "node7", "node8", "node9", "node10");
+
+        logger.info("--> complete relocation");
+        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+        ClusterState newState = addNodes(clusterState, strategy, "zone3", "node11", "node12", "node13", "node14", "node15");
+
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(60));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
+
+        assertThat(newState.getRoutingNodes().node("node11").size(), equalTo(4));
+        assertThat(newState.getRoutingNodes().node("node12").size(), equalTo(4));
+        assertThat(newState.getRoutingNodes().node("node13").size(), equalTo(4));
+        assertThat(newState.getRoutingNodes().node("node14").size(), equalTo(4));
+        assertThat(newState.getRoutingNodes().node("node15").size(), equalTo(4));
+
+        logger.info("--> Removing three nodes from zone3");
+        newState = removeNodes(newState, strategy, "node11", "node12", "node13");
+
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
+
+        // Each node can take 6 shards max (2 + ceil(4*1.0)), so all shards should be assigned
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(60));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
+
+        logger.info("add another index with 30 primary 1 replica");
+        metadata = Metadata.builder(newState.metadata())
+            .put(
+                IndexMetadata.builder("test1")
+                    .settings(
+                        settings(Version.CURRENT).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 30)
+                            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+                    )
+            )
+            .build();
+        RoutingTable updatedRoutingTable = RoutingTable.builder(newState.routingTable()).addAsNew(metadata.index("test1")).build();
+
+        newState = ClusterState.builder(newState).metadata(metadata).routingTable(updatedRoutingTable).build();
+        newState = strategy.reroute(newState, "reroute");
+
+        newState = startInitializingShardsAndReroute(strategy, newState);
+
+        // add the removed node
+        newState = ClusterState.builder(newState)
+            .nodes(DiscoveryNodes.builder(newState.nodes()).add(newNode("node11", singletonMap("zone", "zone3"))))
+            .build();
+        newState = strategy.reroute(newState, "reroute");
+
+        newState = startInitializingShardsAndReroute(strategy, newState);
+
+        // add the removed node
+        newState = ClusterState.builder(newState)
+            .nodes(DiscoveryNodes.builder(newState.nodes()).add(newNode("node12", singletonMap("zone", "zone3"))))
+            .build();
+        newState = strategy.reroute(newState, "reroute");
+
+        newState = startInitializingShardsAndReroute(strategy, newState);
+
+        // add the removed node
+        newState = ClusterState.builder(newState)
+            .nodes(DiscoveryNodes.builder(newState.nodes()).add(newNode("node13", singletonMap("zone", "zone3"))))
+            .build();
+        newState = strategy.reroute(newState, "reroute");
+
+        while (newState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
+            newState = startInitializingShardsAndReroute(strategy, newState);
+        }
+        assertThat(newState.getRoutingNodes().node("node13").size(), equalTo(8));
+        assertThat(newState.getRoutingNodes().node("node12").size(), equalTo(8));
+        assertThat(newState.getRoutingNodes().node("node11").size(), equalTo(8));
+        // ensure all shards are assigned
+        assertThat(newState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(120));
+        assertThat(newState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(0));
+    }
+
     private ClusterState removeNodes(ClusterState clusterState, AllocationService allocationService, String... nodeIds) {
         DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.getNodes());
-        org.opensearch.common.collect.List.of(nodeIds).forEach(nodeId -> nodeBuilder.remove(nodeId));
+        List.of(nodeIds).forEach(nodeId -> nodeBuilder.remove(nodeId));
         return allocationService.disassociateDeadNodes(ClusterState.builder(clusterState).nodes(nodeBuilder).build(), true, "reroute");
     }
 
     private ClusterState addNodes(ClusterState clusterState, AllocationService allocationService, String zone, String... nodeIds) {
         DiscoveryNodes.Builder nodeBuilder = DiscoveryNodes.builder(clusterState.nodes());
-        org.opensearch.common.collect.List.of(nodeIds).forEach(nodeId -> nodeBuilder.add(newNode(nodeId, singletonMap("zone", zone))));
+        List.of(nodeIds).forEach(nodeId -> nodeBuilder.add(newNode(nodeId, singletonMap("zone", zone))));
         clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
         return allocationService.reroute(clusterState, "reroute");
     }
@@ -1097,7 +1229,6 @@ private Settings buildSettings(Map<String, Object> settingsValue) {
             .put(ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_CONCURRENT_RECOVERIES_SETTING.getKey(), 20)
             .put(ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_PRIMARIES_RECOVERIES_SETTING.getKey(), 20)
             .put(ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING.getKey(), 20)
-            .put(ClusterRebalanceAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ALLOW_REBALANCE_SETTING.getKey(), "always")
             .put("cluster.routing.allocation.awareness.attributes", "zone");
         settingsValue.forEach((k, v) -> {
             if (v instanceof Integer) settingsBuilder.put(k, (Integer) (v));
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java
index 5972cc9981254..ac16c5db05a99 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java
@@ -36,8 +36,8 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -63,11 +63,11 @@
 import org.opensearch.cluster.routing.allocation.decider.ReplicaAfterPrimaryActiveAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.snapshots.InternalSnapshotsInfoService;
@@ -80,7 +80,9 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.shuffle;
@@ -338,21 +340,21 @@ public void testRebalanceDoesNotAllocatePrimaryAndReplicasOnDifferentVersionNode
             "newNode",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         final DiscoveryNode oldNode1 = new DiscoveryNode(
             "oldNode1",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             VersionUtils.getPreviousVersion()
         );
         final DiscoveryNode oldNode2 = new DiscoveryNode(
             "oldNode2",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             VersionUtils.getPreviousVersion()
         );
         AllocationId allocationId1P = AllocationId.newInitializing();
@@ -438,7 +440,9 @@ public void testRebalanceDoesNotAllocatePrimaryAndReplicasOnDifferentVersionNode
             .routingTable(routingTable)
             .nodes(DiscoveryNodes.builder().add(newNode).add(oldNode1).add(oldNode2))
             .build();
-        AllocationDeciders allocationDeciders = new AllocationDeciders(Collections.singleton(new NodeVersionAllocationDecider()));
+        AllocationDeciders allocationDeciders = new AllocationDeciders(
+            Collections.singleton(new NodeVersionAllocationDecider(Settings.EMPTY))
+        );
         AllocationService strategy = new MockAllocationService(
             allocationDeciders,
             new TestGatewayAllocator(),
@@ -457,21 +461,21 @@ public void testRestoreDoesNotAllocateSnapshotOnOlderNodes() {
             "newNode",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         final DiscoveryNode oldNode1 = new DiscoveryNode(
             "oldNode1",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             VersionUtils.getPreviousVersion()
         );
         final DiscoveryNode oldNode2 = new DiscoveryNode(
             "oldNode2",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             VersionUtils.getPreviousVersion()
         );
 
@@ -488,9 +492,7 @@ public void testRestoreDoesNotAllocateSnapshotOnOlderNodes() {
         }
         Metadata metadata = Metadata.builder().put(indexMetadata).build();
 
-        final ImmutableOpenMap.Builder<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes = ImmutableOpenMap.builder(
-            numberOfShards
-        );
+        final Map<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes = new HashMap<>(numberOfShards);
         final Index index = metadata.index("test").getIndex();
         for (int i = 0; i < numberOfShards; i++) {
             final ShardId shardId = new ShardId(index, i);
@@ -510,14 +512,14 @@ public void testRestoreDoesNotAllocateSnapshotOnOlderNodes() {
             .nodes(DiscoveryNodes.builder().add(newNode).add(oldNode1).add(oldNode2))
             .build();
         AllocationDeciders allocationDeciders = new AllocationDeciders(
-            Arrays.asList(new ReplicaAfterPrimaryActiveAllocationDecider(), new NodeVersionAllocationDecider())
+            Arrays.asList(new ReplicaAfterPrimaryActiveAllocationDecider(), new NodeVersionAllocationDecider(Settings.EMPTY))
         );
         AllocationService strategy = new MockAllocationService(
             allocationDeciders,
             new TestGatewayAllocator(),
             new BalancedShardsAllocator(Settings.EMPTY),
             EmptyClusterInfoService.INSTANCE,
-            () -> new SnapshotShardSizeInfo(snapshotShardSizes.build())
+            () -> new SnapshotShardSizeInfo(snapshotShardSizes)
         );
         state = strategy.reroute(state, new AllocationCommands(), true, false).getClusterState();
 
@@ -527,6 +529,148 @@ public void testRestoreDoesNotAllocateSnapshotOnOlderNodes() {
         }
     }
 
+    public void testRebalanceDoesNotAllocatePrimaryOnHigherVersionNodesSegrepEnabled() {
+        ShardId shard1 = new ShardId("test1", "_na_", 0);
+        ShardId shard2 = new ShardId("test2", "_na_", 0);
+        final DiscoveryNode newNode1 = new DiscoveryNode(
+            "newNode1",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            CLUSTER_MANAGER_DATA_ROLES,
+            Version.CURRENT
+        );
+        final DiscoveryNode newNode2 = new DiscoveryNode(
+            "newNode2",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            CLUSTER_MANAGER_DATA_ROLES,
+            Version.CURRENT
+        );
+        final DiscoveryNode oldNode1 = new DiscoveryNode(
+            "oldNode1",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            CLUSTER_MANAGER_DATA_ROLES,
+            VersionUtils.getPreviousVersion()
+        );
+        final DiscoveryNode oldNode2 = new DiscoveryNode(
+            "oldNode2",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            CLUSTER_MANAGER_DATA_ROLES,
+            VersionUtils.getPreviousVersion()
+        );
+        AllocationId allocationId1P = AllocationId.newInitializing();
+        AllocationId allocationId1R = AllocationId.newInitializing();
+        AllocationId allocationId2P = AllocationId.newInitializing();
+        AllocationId allocationId2R = AllocationId.newInitializing();
+
+        Settings segmentReplicationSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        Metadata metadata = Metadata.builder()
+            .put(
+                IndexMetadata.builder(shard1.getIndexName())
+                    .settings(settings(Version.CURRENT).put(segmentReplicationSettings))
+                    .numberOfShards(1)
+                    .numberOfReplicas(1)
+                    .putInSyncAllocationIds(0, Sets.newHashSet(allocationId1P.getId(), allocationId1R.getId()))
+            )
+            .put(
+                IndexMetadata.builder(shard2.getIndexName())
+                    .settings(settings(Version.CURRENT).put(segmentReplicationSettings))
+                    .numberOfShards(1)
+                    .numberOfReplicas(1)
+                    .putInSyncAllocationIds(0, Sets.newHashSet(allocationId2P.getId(), allocationId2R.getId()))
+            )
+            .build();
+        RoutingTable routingTable = RoutingTable.builder()
+            .add(
+                IndexRoutingTable.builder(shard1.getIndex())
+                    .addIndexShard(
+                        new IndexShardRoutingTable.Builder(shard1).addShard(
+                            TestShardRouting.newShardRouting(
+                                shard1.getIndexName(),
+                                shard1.getId(),
+                                oldNode1.getId(),
+                                null,
+                                true,
+                                ShardRoutingState.STARTED,
+                                allocationId1P
+                            )
+                        )
+                            .addShard(
+                                TestShardRouting.newShardRouting(
+                                    shard1.getIndexName(),
+                                    shard1.getId(),
+                                    oldNode2.getId(),
+                                    null,
+                                    false,
+                                    ShardRoutingState.STARTED,
+                                    allocationId1R
+                                )
+                            )
+                            .build()
+                    )
+            )
+            .add(
+                IndexRoutingTable.builder(shard2.getIndex())
+                    .addIndexShard(
+                        new IndexShardRoutingTable.Builder(shard2).addShard(
+                            TestShardRouting.newShardRouting(
+                                shard2.getIndexName(),
+                                shard2.getId(),
+                                oldNode2.getId(),
+                                null,
+                                true,
+                                ShardRoutingState.STARTED,
+                                allocationId2P
+                            )
+                        )
+                            .addShard(
+                                TestShardRouting.newShardRouting(
+                                    shard2.getIndexName(),
+                                    shard2.getId(),
+                                    oldNode1.getId(),
+                                    null,
+                                    false,
+                                    ShardRoutingState.STARTED,
+                                    allocationId2R
+                                )
+                            )
+                            .build()
+                    )
+            )
+            .build();
+        ClusterState state = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable)
+            .nodes(DiscoveryNodes.builder().add(newNode1).add(newNode2).add(oldNode1).add(oldNode2))
+            .build();
+        AllocationDeciders allocationDeciders = new AllocationDeciders(
+            Collections.singleton(new NodeVersionAllocationDecider(segmentReplicationSettings))
+        );
+        AllocationService strategy = new MockAllocationService(
+            allocationDeciders,
+            new TestGatewayAllocator(),
+            new BalancedShardsAllocator(Settings.EMPTY),
+            EmptyClusterInfoService.INSTANCE,
+            EmptySnapshotsInfoService.INSTANCE
+        );
+        state = strategy.reroute(state, new AllocationCommands(), true, false).getClusterState();
+        // the two indices must stay as is, the replicas cannot move to oldNode2 because versions don't match
+        assertThat(state.routingTable().index(shard2.getIndex()).shardsWithState(ShardRoutingState.RELOCATING).size(), equalTo(1));
+        assertThat(
+            state.routingTable().index(shard2.getIndex()).shardsWithState(ShardRoutingState.RELOCATING).get(0).primary(),
+            equalTo(false)
+        );
+        assertThat(state.routingTable().index(shard1.getIndex()).shardsWithState(ShardRoutingState.RELOCATING).size(), equalTo(1));
+        assertThat(
+            state.routingTable().index(shard1.getIndex()).shardsWithState(ShardRoutingState.RELOCATING).get(0).primary(),
+            equalTo(false)
+        );
+    }
+
     private ClusterState stabilize(ClusterState clusterState, AllocationService service) {
         logger.trace("RoutingNodes: {}", clusterState.getRoutingNodes());
 
@@ -627,7 +771,7 @@ public void testMessages() {
         RoutingAllocation routingAllocation = new RoutingAllocation(null, clusterState.getRoutingNodes(), clusterState, null, null, 0);
         routingAllocation.debugDecision(true);
 
-        final NodeVersionAllocationDecider allocationDecider = new NodeVersionAllocationDecider();
+        final NodeVersionAllocationDecider allocationDecider = new NodeVersionAllocationDecider(Settings.EMPTY);
         Decision decision = allocationDecider.canAllocate(primaryShard, newNode, routingAllocation);
         assertThat(decision.type(), is(Decision.Type.YES));
         assertThat(decision.getExplanation(), is("the primary shard is new or already existed on the node"));
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RandomAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RandomAllocationDeciderTests.java
index 3f7a998accafe..b5e067de4ed23 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/RandomAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RandomAllocationDeciderTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.Metadata.Builder;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsAllocateUnassignedTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsAllocateUnassignedTests.java
new file mode 100644
index 0000000000000..ed178ed7e1526
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsAllocateUnassignedTests.java
@@ -0,0 +1,123 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingPool;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.allocator.RemoteShardsBalancer;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class RemoteShardsAllocateUnassignedTests extends RemoteShardsBalancerBaseTestCase {
+
+    /**
+     * Test Remote Shards Balancer initialization.
+     */
+    public void testInit() {
+        int localOnlyNodes = 7;
+        int remoteCapableNodes = 3;
+        int localIndices = 10;
+        int remoteIndices = 15;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        RoutingNodes routingNodes = new RoutingNodes(clusterState, false);
+        RoutingAllocation allocation = getRoutingAllocation(clusterState, routingNodes);
+
+        RemoteShardsBalancer remoteShardsBalancer = new RemoteShardsBalancer(logger, allocation);
+        Map<String, RemoteShardsBalancer.UnassignedIndexShards> unassignedShardMap = remoteShardsBalancer.groupUnassignedShardsByIndex();
+
+        assertEquals(remoteIndices, unassignedShardMap.size());
+        for (String index : unassignedShardMap.keySet()) {
+            assertTrue(index.startsWith(REMOTE_IDX_PREFIX));
+            RemoteShardsBalancer.UnassignedIndexShards indexShards = unassignedShardMap.get(index);
+            assertEquals(5, indexShards.getPrimaries().size());
+            for (ShardRouting shard : indexShards.getPrimaries()) {
+                assertTrue(shard.primary());
+                assertEquals(shard.getIndexName(), index);
+            }
+            assertEquals(5, indexShards.getReplicas().size());
+            for (ShardRouting shard : indexShards.getReplicas()) {
+                assertFalse(shard.primary());
+                assertEquals(shard.getIndexName(), index);
+            }
+        }
+    }
+
+    /**
+     * Test remote unassigned shard allocation for standard new cluster setup.
+     */
+    public void testPrimaryAllocation() {
+        int localOnlyNodes = 7;
+        int remoteCapableNodes = 3;
+        int localIndices = 10;
+        int remoteIndices = 13;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        RoutingNodes routingNodes = clusterState.getRoutingNodes();
+        RoutingAllocation allocation = getRoutingAllocation(clusterState, routingNodes);
+
+        assertEquals(0, routingNodes.unassigned().size());
+
+        final Map<String, Integer> nodePrimariesCounter = new HashMap<>();
+        for (ShardRouting shard : clusterState.getRoutingTable().allShards()) {
+            assertFalse(shard.unassigned());
+            RoutingNode node = routingNodes.node(shard.currentNodeId());
+            RoutingPool nodePool = RoutingPool.getNodePool(node);
+            RoutingPool shardPool = RoutingPool.getShardPool(shard, allocation);
+            if (RoutingPool.REMOTE_CAPABLE.equals(shardPool)) {
+                assertEquals(nodePool, shardPool);
+            }
+            if (RoutingPool.getNodePool(node) == RoutingPool.REMOTE_CAPABLE
+                && RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation))
+                && shard.primary()) {
+                nodePrimariesCounter.compute(node.nodeId(), (k, v) -> (v == null) ? 1 : v + 1);
+            }
+        }
+        final int indexShardLimit = (int) Math.ceil(totalPrimaries(remoteIndices) / (float) remoteCapableNodes);
+        for (int primaries : nodePrimariesCounter.values()) {
+            assertTrue(primaries <= indexShardLimit);
+        }
+    }
+
+    /**
+     * Test remote unassigned shard allocation when remote capable nodes fail to come up.
+     */
+    public void testAllocationRemoteCapableNodesUnavailable() {
+        int localOnlyNodes = 7;
+        int remoteCapableNodes = 0;
+        int localIndices = 10;
+        int remoteIndices = 13;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        RoutingNodes routingNodes = clusterState.getRoutingNodes();
+        RoutingAllocation allocation = getRoutingAllocation(clusterState, routingNodes);
+
+        assertEquals(totalShards(remoteIndices), routingNodes.unassigned().size());
+
+        for (ShardRouting shard : clusterState.getRoutingTable().allShards()) {
+            if (RoutingPool.getShardPool(shard, allocation) == RoutingPool.REMOTE_CAPABLE) {
+                assertTrue(shard.unassigned());
+            } else {
+                assertFalse(shard.unassigned());
+                RoutingNode node = routingNodes.node(shard.currentNodeId());
+                assertEquals(RoutingPool.LOCAL_ONLY, RoutingPool.getNodePool(node));
+            }
+        }
+        for (RoutingNode node : routingNodes) {
+            if (RoutingPool.getNodePool(node) == RoutingPool.REMOTE_CAPABLE) {
+                assertEquals(0, node.size());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsBalancerBaseTestCase.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsBalancerBaseTestCase.java
new file mode 100644
index 0000000000000..dbb08a999877d
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsBalancerBaseTestCase.java
@@ -0,0 +1,250 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterInfo;
+import org.opensearch.cluster.ClusterModule;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.DiskUsage;
+import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
+import org.opensearch.cluster.routing.allocation.allocator.ShardsAllocator;
+import org.opensearch.cluster.routing.allocation.decider.AllocationDecider;
+import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexModule;
+import org.opensearch.test.gateway.TestGatewayAllocator;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
+
+@SuppressForbidden(reason = "feature flag overrides")
+public abstract class RemoteShardsBalancerBaseTestCase extends OpenSearchAllocationTestCase {
+    protected static final String LOCAL_NODE_PREFIX = "local-only-node";
+    protected static final String REMOTE_NODE_PREFIX = "remote-capable-node";
+    protected static final String LOCAL_IDX_PREFIX = "local-idx";
+    protected static final String REMOTE_IDX_PREFIX = "remote-idx";
+    protected static final Set<DiscoveryNodeRole> MANAGER_DATA_ROLES = Set.of(
+        DiscoveryNodeRole.CLUSTER_MANAGER_ROLE,
+        DiscoveryNodeRole.DATA_ROLE
+    );
+    protected static final Set<DiscoveryNodeRole> SEARCH_DATA_ROLES = Set.of(
+        DiscoveryNodeRole.CLUSTER_MANAGER_ROLE,
+        DiscoveryNodeRole.DATA_ROLE,
+        DiscoveryNodeRole.SEARCH_ROLE
+    );
+    protected static final Set<DiscoveryNodeRole> SEARCH_ONLY_ROLE = Set.of(DiscoveryNodeRole.SEARCH_ROLE);
+
+    protected static final int PRIMARIES = 5;
+    protected static final int REPLICAS = 1;
+    private static final int MAX_REROUTE_ITERATIONS = 1000;
+
+    protected ClusterSettings EMPTY_CLUSTER_SETTINGS = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+    public String getNodeId(int id, boolean isRemote, String prefix) {
+        if (isRemote) {
+            return REMOTE_NODE_PREFIX + "-" + prefix + "-" + id;
+        }
+        return LOCAL_NODE_PREFIX + "-" + prefix + "-" + id;
+    }
+
+    public String getNodeId(int id, boolean isRemote) {
+        return getNodeId(id, isRemote, "");
+    }
+
+    public String getIndexName(int id, boolean isRemote, String prefix) {
+        if (isRemote) {
+            return REMOTE_IDX_PREFIX + "-" + prefix + "-" + id;
+        }
+        return LOCAL_IDX_PREFIX + "-" + prefix + "-" + id;
+    }
+
+    public String getIndexName(int id, boolean isRemote) {
+        return getIndexName(id, isRemote, "");
+    }
+
+    public RoutingAllocation getRoutingAllocation(ClusterState clusterState, RoutingNodes routingNodes) {
+        return new RoutingAllocation(
+            randomAllocationDeciders(Settings.Builder.EMPTY_SETTINGS, EMPTY_CLUSTER_SETTINGS, random()),
+            routingNodes,
+            clusterState,
+            EmptyClusterInfoService.INSTANCE.getClusterInfo(),
+            null,
+            System.nanoTime()
+        );
+    }
+
+    public ClusterState createInitialCluster(int localOnlyNodes, int remoteNodes, int localIndices, int remoteIndices) {
+        return createInitialCluster(localOnlyNodes, remoteNodes, false, localIndices, remoteIndices);
+    }
+
+    public ClusterState createInitialCluster(int localOnlyNodes, int remoteNodes, boolean remoteOnly, int localIndices, int remoteIndices) {
+        Metadata.Builder mb = Metadata.builder();
+        for (int i = 0; i < localIndices; i++) {
+            mb.put(
+                IndexMetadata.builder(getIndexName(i, false))
+                    .settings(settings(Version.CURRENT).put(UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "0"))
+                    .numberOfShards(PRIMARIES)
+                    .numberOfReplicas(REPLICAS)
+            );
+        }
+
+        for (int i = 0; i < remoteIndices; i++) {
+            mb.put(
+                IndexMetadata.builder(getIndexName(i, true))
+                    .settings(
+                        settings(Version.CURRENT).put(UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "0")
+                            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                    )
+                    .numberOfShards(PRIMARIES)
+                    .numberOfReplicas(REPLICAS)
+            );
+        }
+        Metadata metadata = mb.build();
+
+        RoutingTable.Builder rb = RoutingTable.builder();
+        for (int i = 0; i < localIndices; i++) {
+            rb.addAsNew(metadata.index(getIndexName(i, false)));
+        }
+        for (int i = 0; i < remoteIndices; i++) {
+            rb.addAsNew(metadata.index(getIndexName(i, true)));
+        }
+        RoutingTable routingTable = rb.build();
+
+        DiscoveryNodes.Builder nb = DiscoveryNodes.builder();
+        for (int i = 0; i < localOnlyNodes; i++) {
+            String name = getNodeId(i, false);
+            nb.add(newNode(name, name, MANAGER_DATA_ROLES));
+        }
+        if (remoteOnly) {
+            for (int i = 0; i < remoteNodes; i++) {
+                String name = getNodeId(i, true);
+                nb.add(newNode(name, name, SEARCH_ONLY_ROLE));
+            }
+        } else {
+            for (int i = 0; i < remoteNodes; i++) {
+                String name = getNodeId(i, true);
+                nb.add(newNode(name, name, SEARCH_DATA_ROLES));
+            }
+        }
+        DiscoveryNodes nodes = nb.build();
+        return ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).routingTable(routingTable).nodes(nodes).build();
+    }
+
+    protected ClusterState createRemoteIndex(ClusterState state, String indexName) {
+        Metadata metadata = Metadata.builder(state.metadata())
+            .put(
+                IndexMetadata.builder(indexName)
+                    .settings(
+                        settings(Version.CURRENT).put(UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "5m")
+                            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                    )
+                    .numberOfShards(PRIMARIES)
+                    .numberOfReplicas(REPLICAS)
+            )
+            .build();
+        RoutingTable routingTable = RoutingTable.builder(state.routingTable()).addAsNew(metadata.index(indexName)).build();
+        return ClusterState.builder(state).metadata(metadata).routingTable(routingTable).build();
+    }
+
+    private AllocationDeciders remoteAllocationDeciders(Settings settings, ClusterSettings clusterSettings) {
+        List<AllocationDecider> deciders = new ArrayList<>(
+            ClusterModule.createAllocationDeciders(settings, clusterSettings, Collections.emptyList())
+        );
+        Collections.shuffle(deciders, random());
+        return new AllocationDeciders(deciders);
+    }
+
+    public AllocationService createRemoteCapableAllocationService() {
+        Settings settings = Settings.Builder.EMPTY_SETTINGS;
+        return new OpenSearchAllocationTestCase.MockAllocationService(
+            randomAllocationDeciders(settings, EMPTY_CLUSTER_SETTINGS, random()),
+            new TestGatewayAllocator(),
+            createShardAllocator(settings),
+            EmptyClusterInfoService.INSTANCE,
+            SNAPSHOT_INFO_SERVICE_WITH_NO_SHARD_SIZES
+        );
+    }
+
+    public AllocationService createRemoteCapableAllocationService(String excludeNodes) {
+        Settings settings = Settings.builder().put("cluster.routing.allocation.exclude.node_id", excludeNodes).build();
+        return new MockAllocationService(
+            randomAllocationDeciders(settings, EMPTY_CLUSTER_SETTINGS, random()),
+            new TestGatewayAllocator(),
+            createShardAllocator(settings),
+            EmptyClusterInfoService.INSTANCE,
+            SNAPSHOT_INFO_SERVICE_WITH_NO_SHARD_SIZES
+        );
+    }
+
+    public AllocationDeciders createAllocationDeciders() {
+        Settings settings = Settings.Builder.EMPTY_SETTINGS;
+        return randomAllocationDeciders(settings, EMPTY_CLUSTER_SETTINGS, random());
+
+    }
+
+    public ClusterState allocateShardsAndBalance(ClusterState clusterState, AllocationService service) {
+        int iterations = 0;
+        do {
+            clusterState = service.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+            clusterState = service.reroute(clusterState, "reroute");
+            iterations++;
+        } while (!clusterState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() && iterations < MAX_REROUTE_ITERATIONS);
+        return clusterState;
+    }
+
+    public int totalShards(int indices) {
+        return indices * PRIMARIES * (REPLICAS + 1);
+    }
+
+    public int totalPrimaries(int indices) {
+        return indices * PRIMARIES;
+    }
+
+    public ShardsAllocator createShardAllocator(Settings settings) {
+        ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        return new BalancedShardsAllocator(settings, clusterSettings);
+    }
+
+    /**
+     * ClusterInfo that always reports /dev/null for the shards' data paths.
+     */
+    public static class DevNullClusterInfo extends ClusterInfo {
+        public DevNullClusterInfo(
+            final Map<String, DiskUsage> leastAvailableSpaceUsage,
+            final Map<String, DiskUsage> mostAvailableSpaceUsage,
+            final Map<String, Long> shardSizes
+        ) {
+            super(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, null, Map.of(), Map.of());
+        }
+
+        @Override
+        public String getDataPath(ShardRouting shardRouting) {
+            return "/dev/null";
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsMoveShardsTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsMoveShardsTests.java
new file mode 100644
index 0000000000000..f2e79b319d0dd
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsMoveShardsTests.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.health.ClusterHealthStatus;
+import org.opensearch.cluster.health.ClusterStateHealth;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.index.IndexModule;
+
+public class RemoteShardsMoveShardsTests extends RemoteShardsBalancerBaseTestCase {
+
+    /**
+     * Test reroute terminates gracefully if shards cannot move out of the excluded node
+     */
+    public void testExcludeNodeIdMoveBlocked() {
+        int localOnlyNodes = 7;
+        int remoteCapableNodes = 2;
+        int localIndices = 10;
+        int remoteIndices = 13;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        assertEquals(ClusterHealthStatus.GREEN, (new ClusterStateHealth(clusterState)).getStatus());
+
+        // Exclude a node
+        final String excludedNodeID = getNodeId(0, true);
+        service = createRemoteCapableAllocationService(excludedNodeID);
+        clusterState = allocateShardsAndBalance(clusterState, service);
+
+        RoutingNodes routingNodes = clusterState.getRoutingNodes();
+        assertEquals(ClusterHealthStatus.GREEN, (new ClusterStateHealth(clusterState)).getStatus());
+        assertEquals(0, routingNodes.unassigned().size());
+        assertTrue(routingNodes.node(excludedNodeID).size() > 0);
+    }
+
+    /**
+     * Test move operations for index level allocation settings.
+     * Supported for local indices, not supported for remote indices.
+     */
+    public void testIndexLevelExclusions() throws InterruptedException {
+        int localOnlyNodes = 7;
+        int remoteCapableNodes = 3;
+        int localIndices = 10;
+        int remoteIndices = 13;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        RoutingNodes routingNodes = clusterState.getRoutingNodes();
+
+        assertEquals(ClusterHealthStatus.GREEN, (new ClusterStateHealth(clusterState)).getStatus());
+        assertEquals(0, routingNodes.unassigned().size());
+
+        final String excludedLocalOnlyNode = getNodeId(0, false);
+        final String excludedRemoteCapableNode = getNodeId(0, true);
+        final String localIndex = routingNodes.node(excludedLocalOnlyNode).shardsWithState(ShardRoutingState.STARTED).get(0).getIndexName();
+        final String remoteIndex = routingNodes.node(excludedRemoteCapableNode)
+            .shardsWithState(ShardRoutingState.STARTED)
+            .stream()
+            .filter(shardRouting -> shardRouting.getIndexName().startsWith(REMOTE_IDX_PREFIX))
+            .findFirst()
+            .get()
+            .getIndexName();
+
+        Metadata.Builder mb = Metadata.builder(clusterState.metadata());
+        mb.put(
+            IndexMetadata.builder(clusterState.metadata().index(localIndex))
+                .settings(
+                    settings(Version.CURRENT).put("index.number_of_shards", PRIMARIES)
+                        .put("index.number_of_replicas", REPLICAS)
+                        .put("index.routing.allocation.exclude._name", excludedLocalOnlyNode)
+                        .build()
+                )
+        );
+        mb.put(
+            IndexMetadata.builder(clusterState.metadata().index(remoteIndex))
+                .settings(
+                    settings(Version.CURRENT).put("index.number_of_shards", PRIMARIES)
+                        .put("index.number_of_replicas", REPLICAS)
+                        .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                        .put("index.routing.allocation.exclude._name", excludedRemoteCapableNode)
+                        .build()
+                )
+        );
+        clusterState = ClusterState.builder(clusterState).metadata(mb.build()).build();
+
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        assertEquals(ClusterHealthStatus.GREEN, (new ClusterStateHealth(clusterState)).getStatus());
+        RoutingTable routingTable = clusterState.routingTable();
+
+        // No shard of updated local index should be on excluded local capable node
+        assertTrue(routingTable.allShards(localIndex).stream().noneMatch(shard -> shard.currentNodeId().equals(excludedLocalOnlyNode)));
+
+        // Since remote index shards are untouched, at least one shard should
+        // continue to stay on the excluded remote capable node
+        assertTrue(routingTable.allShards(remoteIndex).stream().anyMatch(shard -> shard.currentNodeId().equals(excludedRemoteCapableNode)));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsRebalanceShardsTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsRebalanceShardsTests.java
new file mode 100644
index 0000000000000..ef9ae90e18bb5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RemoteShardsRebalanceShardsTests.java
@@ -0,0 +1,84 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingPool;
+import org.opensearch.cluster.routing.ShardRouting;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class RemoteShardsRebalanceShardsTests extends RemoteShardsBalancerBaseTestCase {
+
+    /**
+     * Test remote shard allocation and balancing for standard new cluster setup.
+     *
+     * Post rebalance primaries should be balanced across all the nodes.
+     */
+    public void testShardAllocationAndRebalance() {
+        int localOnlyNodes = 20;
+        int remoteCapableNodes = 40;
+        int localIndices = 40;
+        int remoteIndices = 80;
+        ClusterState clusterState = createInitialCluster(localOnlyNodes, remoteCapableNodes, localIndices, remoteIndices);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+        RoutingNodes routingNodes = clusterState.getRoutingNodes();
+        RoutingAllocation allocation = getRoutingAllocation(clusterState, routingNodes);
+
+        final Map<String, Integer> nodePrimariesCounter = getShardCounterPerNodeForRemoteCapablePool(clusterState, allocation, true);
+        final Map<String, Integer> nodeReplicaCounter = getShardCounterPerNodeForRemoteCapablePool(clusterState, allocation, false);
+        int avgPrimariesPerNode = getTotalShardCountAcrossNodes(nodePrimariesCounter) / remoteCapableNodes;
+
+        // Primary and replica are balanced post first reroute
+        for (RoutingNode node : routingNodes) {
+            if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getNodePool(node))) {
+                assertInRange(nodePrimariesCounter.get(node.nodeId()), avgPrimariesPerNode, remoteCapableNodes - 1);
+                assertTrue(nodeReplicaCounter.get(node.nodeId()) >= 0);
+            }
+        }
+    }
+
+    private Map<String, Integer> getShardCounterPerNodeForRemoteCapablePool(
+        ClusterState clusterState,
+        RoutingAllocation allocation,
+        boolean primary
+    ) {
+        final Map<String, Integer> nodePrimariesCounter = new HashMap<>();
+        for (ShardRouting shard : clusterState.getRoutingTable().allShards()) {
+            if (RoutingPool.REMOTE_CAPABLE.equals(RoutingPool.getShardPool(shard, allocation)) && shard.primary() == primary) {
+                nodePrimariesCounter.compute(shard.currentNodeId(), (k, v) -> (v == null) ? 1 : v + 1);
+            }
+        }
+        return nodePrimariesCounter;
+    }
+
+    private int getTotalShardCountAcrossNodes(final Map<String, Integer> nodePrimariesCounter) {
+        int totalShardCount = 0;
+        for (int value : nodePrimariesCounter.values()) {
+            totalShardCount += value;
+        }
+        return totalShardCount;
+    }
+
+    /**
+     * Asserts that the expected value is within the variance range.
+     *
+     * Being used to assert the average number of shards per node.
+     * Variance is required in case of non-absolute mean values;
+     * for example, total number of remote capable nodes in a cluster.
+     */
+    private void assertInRange(int actual, int expectedMean, int variance) {
+        assertTrue(actual >= expectedMean - variance);
+        assertTrue(actual <= expectedMean + variance);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/ReplicaAllocatedAfterPrimaryTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/ReplicaAllocatedAfterPrimaryTests.java
index 8afb133cbf248..e2ad8b1cdbb7d 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/ReplicaAllocatedAfterPrimaryTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/ReplicaAllocatedAfterPrimaryTests.java
@@ -36,13 +36,13 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 
 import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/ResizeAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/ResizeAllocationDeciderTests.java
index 2d4422fdf6ced..50c2b55e28f82 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/ResizeAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/ResizeAllocationDeciderTests.java
@@ -34,8 +34,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -49,8 +49,8 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.ResizeAllocationDecider;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/RoutingNodesIntegrityTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/RoutingNodesIntegrityTests.java
index 22d148247a854..85865ce048723 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/RoutingNodesIntegrityTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/RoutingNodesIntegrityTests.java
@@ -49,9 +49,9 @@
 
 import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
 import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
+import static org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
-import static org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider.CLUSTER_ROUTING_ALLOCATION_NODE_INITIAL_REPLICAS_RECOVERIES_SETTING;
 
 public class RoutingNodesIntegrityTests extends OpenSearchAllocationTestCase {
     private final Logger logger = LogManager.getLogger(IndexBalanceTests.class);
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/SameShardRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/SameShardRoutingTests.java
index 36cb68e460418..3bee0d994ebbc 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/SameShardRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/SameShardRoutingTests.java
@@ -55,7 +55,7 @@
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
 
 import java.util.Collections;
@@ -96,7 +96,7 @@ public void testSameHost() {
                             "test1",
                             buildNewFakeTransportAddress(),
                             emptyMap(),
-                            MASTER_DATA_ROLES,
+                            CLUSTER_MANAGER_DATA_ROLES,
                             Version.CURRENT
                         )
                     )
@@ -109,7 +109,7 @@ public void testSameHost() {
                             "test1",
                             buildNewFakeTransportAddress(),
                             emptyMap(),
-                            MASTER_DATA_ROLES,
+                            CLUSTER_MANAGER_DATA_ROLES,
                             Version.CURRENT
                         )
                     )
@@ -138,7 +138,7 @@ public void testSameHost() {
                             "test2",
                             buildNewFakeTransportAddress(),
                             emptyMap(),
-                            MASTER_DATA_ROLES,
+                            CLUSTER_MANAGER_DATA_ROLES,
                             Version.CURRENT
                         )
                     )
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/ShardsLimitAllocationTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/ShardsLimitAllocationTests.java
index 36b55a0954d32..7917d21635562 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/ShardsLimitAllocationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/ShardsLimitAllocationTests.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.hamcrest.Matcher;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
@@ -46,16 +45,16 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider;
 import org.opensearch.common.settings.Settings;
-
-import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
-import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
+import org.hamcrest.Matcher;
 
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static org.hamcrest.Matchers.equalTo;
+import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
+import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
 import static org.hamcrest.Matchers.anyOf;
+import static org.hamcrest.Matchers.equalTo;
 
 public class ShardsLimitAllocationTests extends OpenSearchAllocationTestCase {
     private final Logger logger = LogManager.getLogger(ShardsLimitAllocationTests.class);
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/StartedShardsRoutingTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/StartedShardsRoutingTests.java
index d366d63ba8e6b..786f01a783f09 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/StartedShardsRoutingTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/StartedShardsRoutingTests.java
@@ -47,8 +47,8 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/ThrottlingAllocationTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/ThrottlingAllocationTests.java
index 47111fae31d28..1ccadcade26bb 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/ThrottlingAllocationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/ThrottlingAllocationTests.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation;
 
-import com.carrotsearch.hppc.IntHashSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
@@ -56,10 +54,9 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.ThrottlingAllocationDecider;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.InternalSnapshotsInfoService;
 import org.opensearch.snapshots.Snapshot;
@@ -70,7 +67,9 @@
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -774,9 +773,9 @@ private ClusterState createRecoveryStateAndInitializeAllocations(
         Snapshot snapshot = new Snapshot("repo", new SnapshotId("snap", "randomId"));
         Set<String> snapshotIndices = new HashSet<>();
         String restoreUUID = UUIDs.randomBase64UUID();
-        for (ObjectCursor<IndexMetadata> cursor : metadata.indices().values()) {
-            Index index = cursor.value.getIndex();
-            IndexMetadata.Builder indexMetadataBuilder = IndexMetadata.builder(cursor.value);
+        for (final IndexMetadata cursor : metadata.indices().values()) {
+            Index index = cursor.getIndex();
+            IndexMetadata.Builder indexMetadataBuilder = IndexMetadata.builder(cursor);
 
             final int recoveryType = inputRecoveryType == null ? randomInt(5) : inputRecoveryType.intValue();
             if (recoveryType <= 4) {
@@ -804,7 +803,7 @@ private ClusterState createRecoveryStateAndInitializeAllocations(
                             Version.CURRENT,
                             new IndexId(indexMetadata.getIndex().getName(), UUIDs.randomBase64UUID(random()))
                         ),
-                        new IntHashSet()
+                        new HashSet<>()
                     );
                     break;
                 case 4:
@@ -829,10 +828,10 @@ private ClusterState createRecoveryStateAndInitializeAllocations(
 
         final RoutingTable routingTable = routingTableBuilder.build();
 
-        final ImmutableOpenMap.Builder<String, ClusterState.Custom> restores = ImmutableOpenMap.builder();
+        final Map<String, ClusterState.Custom> restores = new HashMap<>();
         if (snapshotIndices.isEmpty() == false) {
             // Some indices are restored from snapshot, the RestoreInProgress must be set accordingly
-            ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> restoreShards = ImmutableOpenMap.builder();
+            final Map<ShardId, RestoreInProgress.ShardRestoreStatus> restoreShards = new HashMap<>();
             for (ShardRouting shard : routingTable.allShards()) {
                 if (shard.primary() && shard.recoverySource().getType() == RecoverySource.Type.SNAPSHOT) {
                     final ShardId shardId = shard.shardId();
@@ -849,7 +848,7 @@ private ClusterState createRecoveryStateAndInitializeAllocations(
                 snapshot,
                 RestoreInProgress.State.INIT,
                 new ArrayList<>(snapshotIndices),
-                restoreShards.build()
+                restoreShards
             );
             restores.put(RestoreInProgress.TYPE, new RestoreInProgress.Builder().add(restore).build());
         }
@@ -858,7 +857,7 @@ private ClusterState createRecoveryStateAndInitializeAllocations(
             .nodes(DiscoveryNodes.builder().add(node1))
             .metadata(metadataBuilder.build())
             .routingTable(routingTable)
-            .customs(restores.build())
+            .customs(restores)
             .build();
     }
 
@@ -885,14 +884,13 @@ private void addInSyncAllocationIds(
 
     private static class TestSnapshotsInfoService implements SnapshotsInfoService {
 
-        private volatile ImmutableOpenMap<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes = ImmutableOpenMap.of();
+        private volatile Map<InternalSnapshotsInfoService.SnapshotShard, Long> snapshotShardSizes = Map.of();
 
         synchronized void addSnapshotShardSize(Snapshot snapshot, IndexId index, ShardId shard, Long size) {
-            final ImmutableOpenMap.Builder<InternalSnapshotsInfoService.SnapshotShard, Long> newSnapshotShardSizes = ImmutableOpenMap
-                .builder(snapshotShardSizes);
+            final Map<InternalSnapshotsInfoService.SnapshotShard, Long> newSnapshotShardSizes = new HashMap<>(snapshotShardSizes);
             boolean added = newSnapshotShardSizes.put(new InternalSnapshotsInfoService.SnapshotShard(snapshot, index, shard), size) == null;
             assert added : "cannot add snapshot shard size twice";
-            this.snapshotShardSizes = newSnapshotShardSizes.build();
+            this.snapshotShardSizes = Collections.unmodifiableMap(newSnapshotShardSizes);
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecidersTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecidersTests.java
index 7cfc9440a72e1..7a7a60846443a 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecidersTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/AllocationDecidersTests.java
@@ -42,7 +42,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderTests.java
index a2fcf14638d45..bde8a45359814 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import com.carrotsearch.hppc.IntHashSet;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterInfo;
 import org.opensearch.cluster.ClusterInfoService;
@@ -66,11 +65,12 @@
 import org.opensearch.cluster.routing.allocation.command.AllocationCommands;
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.snapshots.InternalSnapshotsInfoService.SnapshotShard;
@@ -84,6 +84,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static java.util.Collections.emptyMap;
@@ -113,17 +114,15 @@ public void testDiskThreshold() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), 0.8)
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "node1", "/dev/null", 100, 10)); // 90% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "node2", "/dev/null", 100, 35)); // 65% used
-        usagesBuilder.put("node3", new DiskUsage("node3", "node3", "/dev/null", 100, 60)); // 40% used
-        usagesBuilder.put("node4", new DiskUsage("node4", "node4", "/dev/null", 100, 80)); // 20% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
-
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 10L); // 10 bytes
-        shardSizesBuilder.put("[test][0][r]", 10L);
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "node1", "/dev/null", 100, 10)); // 90% used
+        usages.put("node2", new DiskUsage("node2", "node2", "/dev/null", 100, 35)); // 65% used
+        usages.put("node3", new DiskUsage("node3", "node3", "/dev/null", 100, 60)); // 40% used
+        usages.put("node4", new DiskUsage("node4", "node4", "/dev/null", 100, 80)); // 20% used
+
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 10L); // 10 bytes
+        shardSizes.put("[test][0][r]", 10L);
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
@@ -286,6 +285,191 @@ public void testDiskThreshold() {
         assertThat(clusterState.getRoutingNodes().node("node4").size(), equalTo(1));
     }
 
+    public void testDiskThresholdForRemoteShards() {
+        Settings diskSettings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), true)
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_LOW_DISK_WATERMARK_SETTING.getKey(), 0.7)
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), 0.8)
+            .build();
+
+        Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "node1", "/dev/null", 100, 10)); // 90% used
+        usages.put("node2", new DiskUsage("node2", "node2", "/dev/null", 100, 35)); // 65% used
+        usages.put("node3", new DiskUsage("node3", "node3", "/dev/null", 100, 60)); // 40% used
+
+        Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 10L); // 10 bytes
+        shardSizes.put("[test][0][r]", 10L);
+
+        Map<String, FileCacheStats> fileCacheStatsMap = new HashMap<>();
+        fileCacheStatsMap.put("node1", new FileCacheStats(0, 0, 1000, 0, 0, 0, 0));
+        fileCacheStatsMap.put("node2", new FileCacheStats(0, 0, 1000, 0, 0, 0, 0));
+        fileCacheStatsMap.put("node3", new FileCacheStats(0, 0, 1000, 0, 0, 0, 0));
+        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes, fileCacheStatsMap);
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        AllocationDeciders deciders = new AllocationDeciders(
+            new HashSet<>(Arrays.asList(new SameShardAllocationDecider(Settings.EMPTY, clusterSettings), makeDecider(diskSettings)))
+        );
+
+        ClusterInfoService cis = () -> {
+            logger.info("--> calling fake getClusterInfo");
+            return clusterInfo;
+        };
+        AllocationService strategy = new AllocationService(
+            deciders,
+            new TestGatewayAllocator(),
+            new BalancedShardsAllocator(Settings.EMPTY),
+            cis,
+            EmptySnapshotsInfoService.INSTANCE
+        );
+
+        Metadata metadata = Metadata.builder()
+            .put(IndexMetadata.builder("test").settings(remoteIndexSettings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
+            .build();
+
+        final RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(initialRoutingTable)
+            .build();
+
+        Set<DiscoveryNodeRole> defaultWithSearchRole = new HashSet<>(CLUSTER_MANAGER_DATA_ROLES);
+        defaultWithSearchRole.add(DiscoveryNodeRole.SEARCH_ROLE);
+
+        logger.info("--> adding two nodes");
+        clusterState = ClusterState.builder(clusterState)
+            .nodes(DiscoveryNodes.builder().add(newNode("node1", defaultWithSearchRole)).add(newNode("node2", defaultWithSearchRole)))
+            .build();
+        clusterState = strategy.reroute(clusterState, "reroute");
+        logShardStates(clusterState);
+
+        // Primary shard should be initializing, replica should not
+        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(2));
+
+        logger.info("--> start the shards (primaries)");
+        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+        logShardStates(clusterState);
+        // Assert that we're able to start the primary
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(2));
+
+        logger.info("--> adding node3");
+
+        clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node3"))).build();
+        clusterState = strategy.reroute(clusterState, "reroute");
+
+        logShardStates(clusterState);
+        // Assert that the replica is initialized now that node3 is available with enough space
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(2));
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(0));
+
+        logger.info("--> start the shards (replicas)");
+        clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+        logShardStates(clusterState);
+        // Assert that the replica couldn't be started since node1 doesn't have enough space
+        assertThat(clusterState.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED).size(), equalTo(2));
+        assertThat(clusterState.getRoutingNodes().node("node1").size(), equalTo(1));
+        assertThat(clusterState.getRoutingNodes().node("node2").size(), equalTo(1));
+        assertThat(clusterState.getRoutingNodes().node("node3").size(), equalTo(0));
+    }
+
+    public void testFileCacheRemoteShardsDecisions() {
+        Settings diskSettings = Settings.builder()
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), true)
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_LOW_DISK_WATERMARK_SETTING.getKey(), "60%")
+            .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "70%")
+            .build();
+
+        // We have an index with 2 primary shards each taking 40 bytes. Each node has 100 bytes available
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 20)); // 80% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 100)); // 0% used
+
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 40L);
+        shardSizes.put("[test][1][p]", 40L);
+        shardSizes.put("[foo][0][p]", 10L);
+
+        // First node has filecache size as 0, second has 1000, greater than the shard sizes.
+        Map<String, FileCacheStats> fileCacheStatsMap = new HashMap<>();
+        fileCacheStatsMap.put("node1", new FileCacheStats(0, 0, 0, 0, 0, 0, 0));
+        fileCacheStatsMap.put("node2", new FileCacheStats(0, 0, 1000, 0, 0, 0, 0));
+
+        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes, fileCacheStatsMap);
+
+        Set<DiscoveryNodeRole> defaultWithSearchRole = new HashSet<>(CLUSTER_MANAGER_DATA_ROLES);
+        defaultWithSearchRole.add(DiscoveryNodeRole.SEARCH_ROLE);
+
+        DiskThresholdDecider diskThresholdDecider = makeDecider(diskSettings);
+        Metadata metadata = Metadata.builder()
+            .put(IndexMetadata.builder("test").settings(remoteIndexSettings(Version.CURRENT)).numberOfShards(2).numberOfReplicas(0))
+            .persistentSettings(Settings.builder().put(FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING.getKey(), 5).build())
+            .build();
+
+        RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+        DiscoveryNode discoveryNode1 = new DiscoveryNode(
+            "node1",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            defaultWithSearchRole,
+            Version.CURRENT
+        );
+        DiscoveryNode discoveryNode2 = new DiscoveryNode(
+            "node2",
+            buildNewFakeTransportAddress(),
+            emptyMap(),
+            defaultWithSearchRole,
+            Version.CURRENT
+        );
+        DiscoveryNodes discoveryNodes = DiscoveryNodes.builder().add(discoveryNode1).add(discoveryNode2).build();
+
+        ClusterState baseClusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(initialRoutingTable)
+            .nodes(discoveryNodes)
+            .build();
+
+        // Two shards consuming each 80% of disk space while 70% is allowed, so shard 0 isn't allowed here
+        ShardRouting firstRouting = TestShardRouting.newShardRouting("test", 0, "node1", null, true, ShardRoutingState.STARTED);
+        ShardRouting secondRouting = TestShardRouting.newShardRouting("test", 1, "node1", null, true, ShardRoutingState.STARTED);
+        RoutingNode firstRoutingNode = new RoutingNode("node1", discoveryNode1, firstRouting, secondRouting);
+        RoutingNode secondRoutingNode = new RoutingNode("node2", discoveryNode2);
+
+        RoutingTable.Builder builder = RoutingTable.builder()
+            .add(
+                IndexRoutingTable.builder(firstRouting.index())
+                    .addIndexShard(new IndexShardRoutingTable.Builder(firstRouting.shardId()).addShard(firstRouting).build())
+                    .addIndexShard(new IndexShardRoutingTable.Builder(secondRouting.shardId()).addShard(secondRouting).build())
+            );
+        ClusterState clusterState = ClusterState.builder(baseClusterState).routingTable(builder.build()).build();
+        RoutingAllocation routingAllocation = new RoutingAllocation(
+            null,
+            new RoutingNodes(clusterState),
+            clusterState,
+            clusterInfo,
+            null,
+            System.nanoTime()
+        );
+        routingAllocation.debugDecision(true);
+        Decision decision = diskThresholdDecider.canRemain(firstRouting, firstRoutingNode, routingAllocation);
+        assertThat(decision.type(), equalTo(Decision.Type.YES));
+
+        decision = diskThresholdDecider.canAllocate(firstRouting, firstRoutingNode, routingAllocation);
+        assertThat(decision.type(), equalTo(Decision.Type.NO));
+
+        assertThat(
+            ((Decision.Single) decision).getExplanation(),
+            containsString("file cache limit reached - remote shard size will exceed configured safeguard ratio")
+        );
+
+        decision = diskThresholdDecider.canAllocate(firstRouting, secondRoutingNode, routingAllocation);
+        assertThat(decision.type(), equalTo(Decision.Type.YES));
+    }
+
     public void testDiskThresholdWithAbsoluteSizes() {
         Settings diskSettings = Settings.builder()
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.getKey(), true)
@@ -294,18 +478,16 @@ public void testDiskThresholdWithAbsoluteSizes() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_FLOOD_STAGE_WATERMARK_SETTING.getKey(), "5b")
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 10)); // 90% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 10)); // 90% used
-        usagesBuilder.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 60)); // 40% used
-        usagesBuilder.put("node4", new DiskUsage("node4", "n4", "/dev/null", 100, 80)); // 20% used
-        usagesBuilder.put("node5", new DiskUsage("node5", "n5", "/dev/null", 100, 85)); // 15% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
-
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 10L); // 10 bytes
-        shardSizesBuilder.put("[test][0][r]", 10L);
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 10)); // 90% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 10)); // 90% used
+        usages.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 60)); // 40% used
+        usages.put("node4", new DiskUsage("node4", "n4", "/dev/null", 100, 80)); // 20% used
+        usages.put("node5", new DiskUsage("node5", "n5", "/dev/null", 100, 85)); // 15% used
+
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 10L); // 10 bytes
+        shardSizes.put("[test][0][r]", 10L);
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
@@ -360,9 +542,7 @@ public void testDiskThresholdWithAbsoluteSizes() {
         logger.info("--> nodeWithoutPrimary: {}", nodeWithoutPrimary);
 
         // Make node without the primary now habitable to replicas
-        usagesBuilder = ImmutableOpenMap.builder(usages);
-        usagesBuilder.put(nodeWithoutPrimary, new DiskUsage(nodeWithoutPrimary, "", "/dev/null", 100, 35)); // 65% used
-        usages = usagesBuilder.build();
+        usages.put(nodeWithoutPrimary, new DiskUsage(nodeWithoutPrimary, "", "/dev/null", 100, 35)); // 65% used
         final ClusterInfo clusterInfo2 = new DevNullClusterInfo(usages, usages, shardSizes);
         cis = () -> {
             logger.info("--> calling fake getClusterInfo");
@@ -540,14 +720,15 @@ public void testDiskThresholdWithShardSizes() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "71%")
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 31)); // 69% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 1));  // 99% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
+        final Map<String, DiskUsage> usages = Map.of(
+            "node1",
+            new DiskUsage("node1", "n1", "/dev/null", 100, 31), // 69% used
+            "node2",
+            new DiskUsage("node2", "n2", "/dev/null", 100, 1)
+        );  // 99% used
 
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 10L); // 10 bytes
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 10L); // 10 bytes
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         AllocationDeciders deciders = new AllocationDeciders(
@@ -612,15 +793,13 @@ public void testUnknownDiskUsage() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), 0.85)
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node2", new DiskUsage("node2", "node2", "/dev/null", 100, 50)); // 50% used
-        usagesBuilder.put("node3", new DiskUsage("node3", "node3", "/dev/null", 100, 0));  // 100% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node2", new DiskUsage("node2", "node2", "/dev/null", 100, 50)); // 50% used
+        usages.put("node3", new DiskUsage("node3", "node3", "/dev/null", 100, 0));  // 100% used
 
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 10L); // 10 bytes
-        shardSizesBuilder.put("[test][0][r]", 10L); // 10 bytes
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 10L); // 10 bytes
+        shardSizes.put("[test][0][r]", 10L); // 10 bytes
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         AllocationDeciders deciders = new AllocationDeciders(
@@ -688,11 +867,11 @@ public void testAverageUsage() {
         RoutingNode rn = new RoutingNode("node1", newNode("node1"));
         DiskThresholdDecider decider = makeDecider(Settings.EMPTY);
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> usages = new HashMap<>();
         usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 50)); // 50% used
         usages.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 0));  // 100% used
 
-        DiskUsage node1Usage = decider.averageUsage(rn, usages.build());
+        DiskUsage node1Usage = decider.averageUsage(rn, usages);
         assertThat(node1Usage.getTotalBytes(), equalTo(100L));
         assertThat(node1Usage.getFreeBytes(), equalTo(25L));
     }
@@ -718,18 +897,16 @@ public void testShardRelocationsTakenIntoAccount() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), 0.8)
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 40)); // 60% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 40)); // 60% used
-        usagesBuilder.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 40)); // 60% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
-
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 14L); // 14 bytes
-        shardSizesBuilder.put("[test][0][r]", 14L);
-        shardSizesBuilder.put("[test2][0][p]", 1L); // 1 bytes
-        shardSizesBuilder.put("[test2][0][r]", 1L);
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 40)); // 60% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 40)); // 60% used
+        usages.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 40)); // 60% used
+
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 14L); // 14 bytes
+        shardSizes.put("[test][0][r]", 14L);
+        shardSizes.put("[test2][0][p]", 1L); // 1 bytes
+        shardSizes.put("[test2][0][r]", 1L);
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         DiskThresholdDecider decider = makeDecider(diskSettings);
@@ -801,18 +978,16 @@ public void testShardRelocationsTakenIntoAccount() {
             logShardStates(clusterState);
         }
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> overfullUsagesBuilder = ImmutableOpenMap.builder();
-        overfullUsagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 40)); // 60% used
-        overfullUsagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 40)); // 60% used
-        overfullUsagesBuilder.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 0));  // 100% used
-        final ImmutableOpenMap<String, DiskUsage> overfullUsages = overfullUsagesBuilder.build();
+        final Map<String, DiskUsage> overfullUsages = new HashMap<>();
+        overfullUsages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 40)); // 60% used
+        overfullUsages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 40)); // 60% used
+        overfullUsages.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 0));  // 100% used
 
-        final ImmutableOpenMap.Builder<String, Long> largerShardSizesBuilder = ImmutableOpenMap.builder();
-        largerShardSizesBuilder.put("[test][0][p]", 14L);
-        largerShardSizesBuilder.put("[test][0][r]", 14L);
-        largerShardSizesBuilder.put("[test2][0][p]", 2L);
-        largerShardSizesBuilder.put("[test2][0][r]", 2L);
-        final ImmutableOpenMap<String, Long> largerShardSizes = largerShardSizesBuilder.build();
+        final Map<String, Long> largerShardSizes = new HashMap<>();
+        largerShardSizes.put("[test][0][p]", 14L);
+        largerShardSizes.put("[test][0][r]", 14L);
+        largerShardSizes.put("[test2][0][p]", 2L);
+        largerShardSizes.put("[test2][0][r]", 2L);
 
         final ClusterInfo overfullClusterInfo = new DevNullClusterInfo(overfullUsages, overfullUsages, largerShardSizes);
 
@@ -872,10 +1047,11 @@ public void testShardRelocationsTakenIntoAccount() {
                     usages,
                     usages,
                     shardSizes,
-                    (new ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace>()).fPut(
+                    Map.of(
                         new ClusterInfo.NodeAndPath("node1", "/dev/null"),
                         new ClusterInfo.ReservedSpace.Builder().add(new ShardId("", "", 0), between(51, 200)).build()
-                    ).build()
+                    ),
+                    Map.of()
                 )
             );
             clusterState = applyStartedShardsUntilNoChange(clusterState, strategy);
@@ -896,16 +1072,14 @@ public void testCanRemainWithShardRelocatingAway() {
             .build();
 
         // We have an index with 2 primary shards each taking 40 bytes. Each node has 100 bytes available
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 20)); // 80% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 100)); // 0% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 20)); // 80% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 100)); // 0% used
 
-        ImmutableOpenMap.Builder<String, Long> shardSizesBuilder = ImmutableOpenMap.builder();
-        shardSizesBuilder.put("[test][0][p]", 40L);
-        shardSizesBuilder.put("[test][1][p]", 40L);
-        shardSizesBuilder.put("[foo][0][p]", 10L);
-        ImmutableOpenMap<String, Long> shardSizes = shardSizesBuilder.build();
+        final Map<String, Long> shardSizes = new HashMap<>();
+        shardSizes.put("[test][0][p]", 40L);
+        shardSizes.put("[test][1][p]", 40L);
+        shardSizes.put("[foo][0][p]", 10L);
 
         final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
@@ -921,14 +1095,14 @@ public void testCanRemainWithShardRelocatingAway() {
             "node1",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         DiscoveryNode discoveryNode2 = new DiscoveryNode(
             "node2",
             buildNewFakeTransportAddress(),
             emptyMap(),
-            MASTER_DATA_ROLES,
+            CLUSTER_MANAGER_DATA_ROLES,
             Version.CURRENT
         );
         DiscoveryNodes discoveryNodes = DiscoveryNodes.builder().add(discoveryNode1).add(discoveryNode2).build();
@@ -1053,17 +1227,16 @@ public void testForSingleDataNode() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "70%")
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 100)); // 0% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 20));  // 80% used
-        usagesBuilder.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 100)); // 0% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 100)); // 0% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 20));  // 80% used
+        usages.put("node3", new DiskUsage("node3", "n3", "/dev/null", 100, 100)); // 0% used
 
         // We have an index with 1 primary shards each taking 40 bytes. Each node has 100 bytes available
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][p]", 40L);
         shardSizes.put("[test][1][p]", 40L);
-        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes.build());
+        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         DiskThresholdDecider diskThresholdDecider = makeDecider(diskSettings);
         Metadata metadata = Metadata.builder()
@@ -1072,7 +1245,7 @@ public void testForSingleDataNode() {
 
         RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
 
-        logger.info("--> adding one master node, one data node");
+        logger.info("--> adding one cluster-manager node, one data node");
         DiscoveryNode discoveryNode1 = new DiscoveryNode(
             "",
             "node1",
@@ -1207,14 +1380,13 @@ public void testWatermarksEnabledForSingleDataNode() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "70%")
             .build();
 
-        ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("data", new DiskUsage("data", "data", "/dev/null", 100, 20));  // 80% used
-        ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("data", new DiskUsage("data", "data", "/dev/null", 100, 20));  // 80% used
 
         // We have an index with 1 primary shard, taking 40 bytes. The single data node has only 20 bytes free.
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][p]", 40L);
-        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes.build());
+        final ClusterInfo clusterInfo = new DevNullClusterInfo(usages, usages, shardSizes);
 
         DiskThresholdDecider diskThresholdDecider = makeDecider(diskSettings);
         Metadata metadata = Metadata.builder()
@@ -1222,9 +1394,9 @@ public void testWatermarksEnabledForSingleDataNode() {
             .build();
         RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
 
-        DiscoveryNode masterNode = new DiscoveryNode(
-            "master",
-            "master",
+        DiscoveryNode clusterManagerNode = new DiscoveryNode(
+            "cluster-manager",
+            "cluster-manager",
             buildNewFakeTransportAddress(),
             emptyMap(),
             singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
@@ -1240,7 +1412,7 @@ public void testWatermarksEnabledForSingleDataNode() {
         );
         DiscoveryNodes.Builder discoveryNodesBuilder = DiscoveryNodes.builder().add(dataNode);
         if (randomBoolean()) {
-            discoveryNodesBuilder.add(masterNode);
+            discoveryNodesBuilder.add(clusterManagerNode);
         }
         DiscoveryNodes discoveryNodes = discoveryNodesBuilder.build();
 
@@ -1319,11 +1491,10 @@ public void testDiskThresholdWithSnapshotShardSizes() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "95%")
             .build();
 
-        final ImmutableOpenMap.Builder<String, DiskUsage> usagesBuilder = ImmutableOpenMap.builder();
-        usagesBuilder.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 21));  // 79% used
-        usagesBuilder.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 1)); // 99% used
-        final ImmutableOpenMap<String, DiskUsage> usages = usagesBuilder.build();
-        final ClusterInfoService clusterInfoService = () -> new DevNullClusterInfo(usages, usages, ImmutableOpenMap.of());
+        final Map<String, DiskUsage> usages = new HashMap<>();
+        usages.put("node1", new DiskUsage("node1", "n1", "/dev/null", 100, 21));  // 79% used
+        usages.put("node2", new DiskUsage("node2", "n2", "/dev/null", 100, 1)); // 99% used
+        final ClusterInfoService clusterInfoService = () -> new DevNullClusterInfo(usages, usages, Map.of());
 
         final AllocationDeciders deciders = new AllocationDeciders(
             new HashSet<>(
@@ -1356,15 +1527,15 @@ public void testDiskThresholdWithSnapshotShardSizes() {
             .addAsNewRestore(
                 metadata.index("test"),
                 new RecoverySource.SnapshotRecoverySource("_restore_uuid", snapshot, Version.CURRENT, indexId),
-                new IntHashSet()
+                new HashSet<>()
             )
             .build();
 
-        final ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shards = ImmutableOpenMap.builder();
+        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards = new HashMap<>();
         shards.put(shardId, new RestoreInProgress.ShardRestoreStatus("node1"));
 
         final RestoreInProgress.Builder restores = new RestoreInProgress.Builder().add(
-            new RestoreInProgress.Entry("_restore_uuid", snapshot, RestoreInProgress.State.INIT, singletonList("test"), shards.build())
+            new RestoreInProgress.Entry("_restore_uuid", snapshot, RestoreInProgress.State.INIT, singletonList("test"), shards)
         );
 
         ClusterState clusterState = ClusterState.builder(new ClusterName(getTestName()))
@@ -1420,7 +1591,7 @@ public void testDiskThresholdWithSnapshotShardSizes() {
         assertThat(clusterState.getRoutingNodes().shardsWithState(UNASSIGNED).size(), equalTo(1));
 
         final SnapshotShard snapshotShard = new SnapshotShard(snapshot, indexId, shardId);
-        final ImmutableOpenMap.Builder<SnapshotShard, Long> snapshotShardSizes = ImmutableOpenMap.builder();
+        final Map<SnapshotShard, Long> snapshotShardSizes = new HashMap<>();
 
         final boolean shouldAllocate;
         if (randomBoolean()) {
@@ -1434,7 +1605,7 @@ public void testDiskThresholdWithSnapshotShardSizes() {
             logger.info("--> shard is always allocated when its size could not be retrieved");
             shouldAllocate = true;
         }
-        snapshotShardSizeInfoRef.set(new SnapshotShardSizeInfo(snapshotShardSizes.build()));
+        snapshotShardSizeInfoRef.set(new SnapshotShardSizeInfo(snapshotShardSizes));
 
         // reroute uses the previous snapshot shard size
         clusterState = startInitializingShardsAndReroute(strategy, clusterState);
@@ -1468,20 +1639,30 @@ public void logShardStates(ClusterState state) {
      */
     static class DevNullClusterInfo extends ClusterInfo {
         DevNullClusterInfo(
-            ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage,
-            ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsage,
-            ImmutableOpenMap<String, Long> shardSizes
+            final Map<String, DiskUsage> leastAvailableSpaceUsage,
+            final Map<String, DiskUsage> mostAvailableSpaceUsage,
+            final Map<String, Long> shardSizes
+        ) {
+            this(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, Map.of(), Map.of());
+        }
+
+        DevNullClusterInfo(
+            final Map<String, DiskUsage> leastAvailableSpaceUsage,
+            final Map<String, DiskUsage> mostAvailableSpaceUsage,
+            final Map<String, Long> shardSizes,
+            final Map<String, FileCacheStats> nodeFileCacheStats
         ) {
-            this(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, ImmutableOpenMap.of());
+            this(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, Map.of(), nodeFileCacheStats);
         }
 
         DevNullClusterInfo(
-            ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage,
-            ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsage,
-            ImmutableOpenMap<String, Long> shardSizes,
-            ImmutableOpenMap<NodeAndPath, ReservedSpace> reservedSpace
+            final Map<String, DiskUsage> leastAvailableSpaceUsage,
+            final Map<String, DiskUsage> mostAvailableSpaceUsage,
+            final Map<String, Long> shardSizes,
+            Map<NodeAndPath, ReservedSpace> reservedSpace,
+            final Map<String, FileCacheStats> nodeFileCacheStats
         ) {
-            super(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, null, reservedSpace);
+            super(leastAvailableSpaceUsage, mostAvailableSpaceUsage, shardSizes, null, reservedSpace, nodeFileCacheStats);
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderUnitTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderUnitTests.java
index bbd9658361114..622d3a2c920b5 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderUnitTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderUnitTests.java
@@ -54,14 +54,15 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
@@ -114,25 +115,19 @@ public void testCanAllocateUsesMaxAvailableSpace() {
         clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder().add(node_0).add(node_1)).build();
 
         // actual test -- after all that bloat :)
-        ImmutableOpenMap.Builder<String, DiskUsage> leastAvailableUsages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> leastAvailableUsages = new HashMap<>();
         leastAvailableUsages.put("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, 0)); // all full
         leastAvailableUsages.put("node_1", new DiskUsage("node_1", "node_1", "_na_", 100, 0)); // all full
 
-        ImmutableOpenMap.Builder<String, DiskUsage> mostAvailableUsage = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> mostAvailableUsage = new HashMap<>();
         // 20 - 99 percent since after allocation there must be at least 10% left and shard is 10byte
         mostAvailableUsage.put("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, randomIntBetween(20, 100)));
         // this is weird and smells like a bug! it should be up to 20%?
         mostAvailableUsage.put("node_1", new DiskUsage("node_1", "node_1", "_na_", 100, randomIntBetween(0, 10)));
 
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][p]", 10L); // 10 bytes
-        final ClusterInfo clusterInfo = new ClusterInfo(
-            leastAvailableUsages.build(),
-            mostAvailableUsage.build(),
-            shardSizes.build(),
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of()
-        );
+        final ClusterInfo clusterInfo = new ClusterInfo(leastAvailableUsages, mostAvailableUsage, shardSizes, Map.of(), Map.of(), Map.of());
         RoutingAllocation allocation = new RoutingAllocation(
             new AllocationDeciders(Collections.singleton(decider)),
             clusterState.getRoutingNodes(),
@@ -198,23 +193,17 @@ public void testCannotAllocateDueToLackOfDiskResources() {
 
         // actual test -- after all that bloat :)
 
-        ImmutableOpenMap.Builder<String, DiskUsage> leastAvailableUsages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> leastAvailableUsages = new HashMap<>();
         leastAvailableUsages.put("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, 0)); // all full
-        ImmutableOpenMap.Builder<String, DiskUsage> mostAvailableUsage = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> mostAvailableUsage = new HashMap<>();
         final int freeBytes = randomIntBetween(20, 100);
         mostAvailableUsage.put("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, freeBytes));
 
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         // way bigger than available space
         final long shardSize = randomIntBetween(110, 1000);
         shardSizes.put("[test][0][p]", shardSize);
-        ClusterInfo clusterInfo = new ClusterInfo(
-            leastAvailableUsages.build(),
-            mostAvailableUsage.build(),
-            shardSizes.build(),
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of()
-        );
+        ClusterInfo clusterInfo = new ClusterInfo(leastAvailableUsages, mostAvailableUsage, shardSizes, Map.of(), Map.of(), Map.of());
         RoutingAllocation allocation = new RoutingAllocation(
             new AllocationDeciders(Collections.singleton(decider)),
             clusterState.getRoutingNodes(),
@@ -245,7 +234,7 @@ public void testCannotAllocateDueToLackOfDiskResources() {
     public void testCanRemainUsesLeastAvailableSpace() {
         ClusterSettings nss = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
         DiskThresholdDecider decider = new DiskThresholdDecider(Settings.EMPTY, nss);
-        ImmutableOpenMap.Builder<ShardRouting, String> shardRoutingMap = ImmutableOpenMap.builder();
+        final Map<ShardRouting, String> shardRoutingMap = new HashMap<>();
 
         DiscoveryNode node_0 = new DiscoveryNode(
             "node_0",
@@ -318,25 +307,26 @@ public void testCanRemainUsesLeastAvailableSpace() {
         clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder().add(node_0).add(node_1)).build();
 
         // actual test -- after all that bloat :)
-        ImmutableOpenMap.Builder<String, DiskUsage> leastAvailableUsages = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> leastAvailableUsages = new HashMap<>();
         leastAvailableUsages.put("node_0", new DiskUsage("node_0", "node_0", "/node0/least", 100, 10)); // 90% used
         leastAvailableUsages.put("node_1", new DiskUsage("node_1", "node_1", "/node1/least", 100, 9)); // 91% used
 
-        ImmutableOpenMap.Builder<String, DiskUsage> mostAvailableUsage = ImmutableOpenMap.builder();
+        final Map<String, DiskUsage> mostAvailableUsage = new HashMap<>();
         mostAvailableUsage.put("node_0", new DiskUsage("node_0", "node_0", "/node0/most", 100, 90)); // 10% used
         mostAvailableUsage.put("node_1", new DiskUsage("node_1", "node_1", "/node1/most", 100, 90)); // 10% used
 
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][p]", 10L); // 10 bytes
         shardSizes.put("[test][1][p]", 10L);
         shardSizes.put("[test][2][p]", 10L);
 
         final ClusterInfo clusterInfo = new ClusterInfo(
-            leastAvailableUsages.build(),
-            mostAvailableUsage.build(),
-            shardSizes.build(),
-            shardRoutingMap.build(),
-            ImmutableOpenMap.of()
+            leastAvailableUsages,
+            mostAvailableUsage,
+            shardSizes,
+            shardRoutingMap,
+            Map.of(),
+            Map.of()
         );
         RoutingAllocation allocation = new RoutingAllocation(
             new AllocationDeciders(Collections.singleton(decider)),
@@ -392,16 +382,12 @@ public void testCanRemainUsesLeastAvailableSpace() {
     }
 
     public void testShardSizeAndRelocatingSize() {
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][r]", 10L);
         shardSizes.put("[test][1][r]", 100L);
         shardSizes.put("[test][2][r]", 1000L);
         shardSizes.put("[other][0][p]", 10000L);
-        ClusterInfo info = new DiskThresholdDeciderTests.DevNullClusterInfo(
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of(),
-            shardSizes.build()
-        );
+        ClusterInfo info = new DiskThresholdDeciderTests.DevNullClusterInfo(Map.of(), Map.of(), shardSizes);
         Metadata.Builder metaBuilder = Metadata.builder();
         metaBuilder.put(
             IndexMetadata.builder("test")
@@ -520,17 +506,13 @@ public long sizeOfRelocatingShards(RoutingAllocation allocation, RoutingNode nod
     }
 
     public void testSizeShrinkIndex() {
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        final Map<String, Long> shardSizes = new HashMap<>();
         shardSizes.put("[test][0][p]", 10L);
         shardSizes.put("[test][1][p]", 100L);
         shardSizes.put("[test][2][p]", 500L);
         shardSizes.put("[test][3][p]", 500L);
 
-        ClusterInfo info = new DiskThresholdDeciderTests.DevNullClusterInfo(
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of(),
-            shardSizes.build()
-        );
+        ClusterInfo info = new DiskThresholdDeciderTests.DevNullClusterInfo(Map.of(), Map.of(), shardSizes);
         Metadata.Builder metaBuilder = Metadata.builder();
         metaBuilder.put(
             IndexMetadata.builder("test")
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationShortCircuitTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationShortCircuitTests.java
index 6a1b3c912ad4a..592de8215cd8f 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationShortCircuitTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/EnableAllocationShortCircuitTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -135,7 +135,7 @@ public void testRebalancingSkippedIfDisabled() {
 
     public void testRebalancingSkippedIfDisabledIncludingOnSpecificIndices() {
         ClusterState clusterState = createClusterStateWithAllShardsAssigned();
-        final IndexMetadata indexMetadata = randomFrom(clusterState.metadata().indices().values().toArray(IndexMetadata.class));
+        final IndexMetadata indexMetadata = randomFrom(clusterState.metadata().indices().values().toArray(new IndexMetadata[0]));
         clusterState = ClusterState.builder(clusterState)
             .metadata(
                 Metadata.builder(clusterState.metadata())
@@ -162,7 +162,7 @@ public void testRebalancingSkippedIfDisabledIncludingOnSpecificIndices() {
 
     public void testRebalancingAttemptedIfDisabledButOverridenOnSpecificIndices() {
         ClusterState clusterState = createClusterStateWithAllShardsAssigned();
-        final IndexMetadata indexMetadata = randomFrom(clusterState.metadata().indices().values().toArray(IndexMetadata.class));
+        final IndexMetadata indexMetadata = randomFrom(clusterState.metadata().indices().values().toArray(new IndexMetadata[0]));
         clusterState = ClusterState.builder(clusterState)
             .metadata(
                 Metadata.builder(clusterState.metadata())
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDeciderTests.java
index 0b00d26182346..a8282faaddced 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/FilterAllocationDeciderTests.java
@@ -33,8 +33,8 @@
 
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.EmptyClusterInfoService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDeciderTests.java
index 5b05cb3afd83e..7e2f258cd0021 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDeciderTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/RestoreInProgressAllocationDeciderTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.cluster.routing.allocation.decider;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -52,14 +51,15 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
 import static java.util.Collections.singletonList;
 
@@ -144,8 +144,8 @@ public void testCanAllocatePrimaryExistingInRestoreInProgress() {
 
             IndexRoutingTable indexRoutingTable = routingTable.index("test");
             IndexRoutingTable.Builder newIndexRoutingTable = IndexRoutingTable.builder(indexRoutingTable.getIndex());
-            for (final ObjectCursor<IndexShardRoutingTable> shardEntry : indexRoutingTable.getShards().values()) {
-                final IndexShardRoutingTable shardRoutingTable = shardEntry.value;
+            for (final var shardEntry : indexRoutingTable.getShards().values()) {
+                final IndexShardRoutingTable shardRoutingTable = shardEntry;
                 for (ShardRouting shardRouting : shardRoutingTable.getShards()) {
                     if (shardRouting.primary()) {
                         newIndexRoutingTable.addShard(primary);
@@ -157,7 +157,7 @@ public void testCanAllocatePrimaryExistingInRestoreInProgress() {
             routingTable = RoutingTable.builder(routingTable).add(newIndexRoutingTable).build();
         }
 
-        ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shards = ImmutableOpenMap.builder();
+        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards = new HashMap<>();
         shards.put(primary.shardId(), new RestoreInProgress.ShardRestoreStatus(clusterState.getNodes().getLocalNodeId(), shardState));
 
         Snapshot snapshot = recoverySource.snapshot();
@@ -167,7 +167,7 @@ public void testCanAllocatePrimaryExistingInRestoreInProgress() {
             snapshot,
             restoreState,
             singletonList("test"),
-            shards.build()
+            shards
         );
 
         clusterState = ClusterState.builder(clusterState)
@@ -199,9 +199,9 @@ private ClusterState createInitialClusterState() {
         RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
 
         DiscoveryNodes discoveryNodes = DiscoveryNodes.builder()
-            .add(newNode("master", Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)))
-            .localNodeId("master")
-            .masterNodeId("master")
+            .add(newNode("cluster-manager", Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)))
+            .localNodeId("cluster-manager")
+            .clusterManagerNodeId("cluster-manager")
             .build();
 
         ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT)
@@ -230,7 +230,7 @@ private Decision executeAllocation(final ClusterState clusterState, final ShardR
         if (randomBoolean()) {
             decision = decider.canAllocate(shardRouting, allocation);
         } else {
-            DiscoveryNode node = clusterState.getNodes().getMasterNode();
+            DiscoveryNode node = clusterState.getNodes().getClusterManagerNode();
             decision = decider.canAllocate(shardRouting, new RoutingNode(node.getId(), node), allocation);
         }
         return decision;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDeciderTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDeciderTests.java
new file mode 100644
index 0000000000000..8f2db5db969d2
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/decider/TargetPoolAllocationDeciderTests.java
@@ -0,0 +1,203 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing.allocation.decider;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.RemoteShardsBalancerBaseTestCase;
+import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+
+import java.util.Collections;
+import java.util.stream.Collectors;
+
+public class TargetPoolAllocationDeciderTests extends RemoteShardsBalancerBaseTestCase {
+    public void testTargetPoolHybridAllocationDecisions() {
+        ClusterState clusterState = createInitialCluster(3, 3, 2, 2);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+
+        // Add an unassigned primary shard for force allocation checks
+        Metadata metadata = Metadata.builder(clusterState.metadata())
+            .put(IndexMetadata.builder("test_local_unassigned").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
+            .build();
+        RoutingTable routingTable = RoutingTable.builder(clusterState.routingTable())
+            .addAsNew(metadata.index("test_local_unassigned"))
+            .build();
+        clusterState = ClusterState.builder(clusterState).metadata(metadata).routingTable(routingTable).build();
+
+        // Add remote index unassigned primary
+        clusterState = createRemoteIndex(clusterState, "test_remote_unassigned");
+
+        RoutingNodes defaultRoutingNodes = clusterState.getRoutingNodes();
+        RoutingAllocation globalAllocation = getRoutingAllocation(clusterState, defaultRoutingNodes);
+
+        ShardRouting localShard = clusterState.routingTable()
+            .allShards(getIndexName(0, false))
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting remoteShard = clusterState.routingTable()
+            .allShards(getIndexName(0, true))
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting unassignedLocalShard = clusterState.routingTable()
+            .allShards("test_local_unassigned")
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting unassignedRemoteShard = clusterState.routingTable()
+            .allShards("test_remote_unassigned")
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        IndexMetadata localIdx = globalAllocation.metadata().getIndexSafe(localShard.index());
+        IndexMetadata remoteIdx = globalAllocation.metadata().getIndexSafe(remoteShard.index());
+        String localNodeId = LOCAL_NODE_PREFIX;
+        for (RoutingNode routingNode : globalAllocation.routingNodes()) {
+            if (routingNode.nodeId().startsWith(LOCAL_NODE_PREFIX)) {
+                localNodeId = routingNode.nodeId();
+                break;
+            }
+        }
+        String remoteNodeId = remoteShard.currentNodeId();
+        RoutingNode localOnlyNode = defaultRoutingNodes.node(localNodeId);
+        RoutingNode remoteCapableNode = defaultRoutingNodes.node(remoteNodeId);
+
+        AllocationDeciders deciders = new AllocationDeciders(Collections.singletonList(new TargetPoolAllocationDecider()));
+
+        // Incompatible Pools
+        assertEquals(Decision.NO.type(), deciders.canAllocate(remoteShard, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.canAllocate(remoteIdx, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.canForceAllocatePrimary(unassignedRemoteShard, localOnlyNode, globalAllocation).type());
+
+        // Compatible Pools
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localShard, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localIdx, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(remoteShard, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(remoteIdx, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localShard, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localIdx, localOnlyNode, globalAllocation).type());
+        assertEquals(
+            Decision.YES.type(),
+            deciders.canForceAllocatePrimary(unassignedRemoteShard, remoteCapableNode, globalAllocation).type()
+        );
+        assertEquals(Decision.YES.type(), deciders.canForceAllocatePrimary(unassignedLocalShard, localOnlyNode, globalAllocation).type());
+        assertEquals(
+            Decision.YES.type(),
+            deciders.canForceAllocatePrimary(unassignedLocalShard, remoteCapableNode, globalAllocation).type()
+        );
+
+        // Verify only remote nodes are used for auto expand replica decision for remote index
+        assertEquals(Decision.YES.type(), deciders.shouldAutoExpandToNode(localIdx, remoteCapableNode.node(), globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.shouldAutoExpandToNode(remoteIdx, localOnlyNode.node(), globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.shouldAutoExpandToNode(localIdx, localOnlyNode.node(), globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.shouldAutoExpandToNode(remoteIdx, remoteCapableNode.node(), globalAllocation).type());
+    }
+
+    public void testTargetPoolDedicatedSearchNodeAllocationDecisions() {
+        ClusterState clusterState = createInitialCluster(3, 3, true, 2, 2);
+        AllocationService service = this.createRemoteCapableAllocationService();
+        clusterState = allocateShardsAndBalance(clusterState, service);
+
+        // Add an unassigned primary shard for force allocation checks
+        Metadata metadata = Metadata.builder(clusterState.metadata())
+            .put(IndexMetadata.builder("test_local_unassigned").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
+            .build();
+        RoutingTable routingTable = RoutingTable.builder(clusterState.routingTable())
+            .addAsNew(metadata.index("test_local_unassigned"))
+            .build();
+        clusterState = ClusterState.builder(clusterState).metadata(metadata).routingTable(routingTable).build();
+
+        // Add remote index unassigned primary
+        clusterState = createRemoteIndex(clusterState, "test_remote_unassigned");
+
+        RoutingNodes defaultRoutingNodes = clusterState.getRoutingNodes();
+        RoutingAllocation globalAllocation = getRoutingAllocation(clusterState, defaultRoutingNodes);
+
+        ShardRouting localShard = clusterState.routingTable()
+            .allShards(getIndexName(0, false))
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting remoteShard = clusterState.routingTable()
+            .allShards(getIndexName(0, true))
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting unassignedLocalShard = clusterState.routingTable()
+            .allShards("test_local_unassigned")
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        ShardRouting unassignedRemoteShard = clusterState.routingTable()
+            .allShards("test_remote_unassigned")
+            .stream()
+            .filter(ShardRouting::primary)
+            .collect(Collectors.toList())
+            .get(0);
+        IndexMetadata localIdx = globalAllocation.metadata().getIndexSafe(localShard.index());
+        IndexMetadata remoteIdx = globalAllocation.metadata().getIndexSafe(remoteShard.index());
+        String localNodeId = LOCAL_NODE_PREFIX;
+        for (RoutingNode routingNode : globalAllocation.routingNodes()) {
+            if (routingNode.nodeId().startsWith(LOCAL_NODE_PREFIX)) {
+                localNodeId = routingNode.nodeId();
+                break;
+            }
+        }
+        String remoteNodeId = remoteShard.currentNodeId();
+        RoutingNode localOnlyNode = defaultRoutingNodes.node(localNodeId);
+        RoutingNode remoteCapableNode = defaultRoutingNodes.node(remoteNodeId);
+
+        AllocationDeciders deciders = new AllocationDeciders(Collections.singletonList(new TargetPoolAllocationDecider()));
+
+        // Incompatible Pools
+        assertEquals(Decision.NO.type(), deciders.canAllocate(remoteShard, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.canAllocate(remoteIdx, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.canForceAllocatePrimary(unassignedRemoteShard, localOnlyNode, globalAllocation).type());
+        // A dedicated search node should not accept local shards and indices.
+        assertEquals(Decision.NO.type(), deciders.canAllocate(localShard, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.canAllocate(localIdx, remoteCapableNode, globalAllocation).type());
+        assertEquals(
+            Decision.NO.type(),
+            deciders.canForceAllocatePrimary(unassignedLocalShard, remoteCapableNode, globalAllocation).type()
+        );
+
+        // Compatible Pools
+        assertEquals(Decision.YES.type(), deciders.canAllocate(remoteShard, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(remoteIdx, remoteCapableNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localShard, localOnlyNode, globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.canAllocate(localIdx, localOnlyNode, globalAllocation).type());
+        assertEquals(
+            Decision.YES.type(),
+            deciders.canForceAllocatePrimary(unassignedRemoteShard, remoteCapableNode, globalAllocation).type()
+        );
+        assertEquals(Decision.YES.type(), deciders.canForceAllocatePrimary(unassignedLocalShard, localOnlyNode, globalAllocation).type());
+
+        // Verify only compatible nodes are used for auto expand replica decision for remote index and local index
+        assertEquals(Decision.NO.type(), deciders.shouldAutoExpandToNode(localIdx, remoteCapableNode.node(), globalAllocation).type());
+        assertEquals(Decision.NO.type(), deciders.shouldAutoExpandToNode(remoteIdx, localOnlyNode.node(), globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.shouldAutoExpandToNode(localIdx, localOnlyNode.node(), globalAllocation).type());
+        assertEquals(Decision.YES.type(), deciders.shouldAutoExpandToNode(remoteIdx, remoteCapableNode.node(), globalAllocation).type());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/serialization/ClusterSerializationTests.java b/server/src/test/java/org/opensearch/cluster/serialization/ClusterSerializationTests.java
index 83e99475dc6a4..b6140b0764191 100644
--- a/server/src/test/java/org/opensearch/cluster/serialization/ClusterSerializationTests.java
+++ b/server/src/test/java/org/opensearch/cluster/serialization/ClusterSerializationTests.java
@@ -39,8 +39,8 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterState.Custom;
 import org.opensearch.cluster.Diff;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.NamedDiff;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.RestoreInProgress;
 import org.opensearch.cluster.SnapshotDeletionsInProgress;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -50,14 +50,13 @@
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.VersionUtils;
@@ -66,6 +65,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.notNullValue;
@@ -85,7 +85,7 @@ public void testClusterStateSerialization() throws Exception {
             .add(newNode("node2"))
             .add(newNode("node3"))
             .localNodeId("node1")
-            .masterNodeId("node2")
+            .clusterManagerNodeId("node2")
             .build();
 
         ClusterState clusterState = ClusterState.builder(new ClusterName("clusterName1"))
@@ -162,7 +162,7 @@ public void testSnapshotDeletionsInProgressSerialization() throws Exception {
                         new Snapshot("repo2", new SnapshotId("snap2", UUIDs.randomBase64UUID())),
                         RestoreInProgress.State.STARTED,
                         Collections.singletonList("index_name"),
-                        ImmutableOpenMap.of()
+                        Map.of()
                     )
                 ).build()
             );
diff --git a/server/src/test/java/org/opensearch/cluster/serialization/ClusterStateToStringTests.java b/server/src/test/java/org/opensearch/cluster/serialization/ClusterStateToStringTests.java
index b2e9b8ddb9ea7..c978325917fe9 100644
--- a/server/src/test/java/org/opensearch/cluster/serialization/ClusterStateToStringTests.java
+++ b/server/src/test/java/org/opensearch/cluster/serialization/ClusterStateToStringTests.java
@@ -42,8 +42,9 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.RoutingTable;
 import org.opensearch.cluster.routing.allocation.AllocationService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 
 import java.util.Arrays;
 
@@ -67,7 +68,7 @@ public void testClusterStateSerialization() throws Exception {
         DiscoveryNodes nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("node_foo", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT))
             .localNodeId("node_foo")
-            .masterNodeId("node_foo")
+            .clusterManagerNodeId("node_foo")
             .build();
 
         ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
@@ -79,7 +80,7 @@ public void testClusterStateSerialization() throws Exception {
         AllocationService strategy = createAllocationService();
         clusterState = ClusterState.builder(clusterState).routingTable(strategy.reroute(clusterState, "reroute").routingTable()).build();
 
-        String clusterStateString = Strings.toString(clusterState);
+        String clusterStateString = Strings.toString(MediaTypeRegistry.JSON, clusterState);
         assertNotNull(clusterStateString);
 
         assertThat(clusterStateString, containsString("test_idx"));
diff --git a/server/src/test/java/org/opensearch/cluster/serialization/DiffableTests.java b/server/src/test/java/org/opensearch/cluster/serialization/DiffableTests.java
index 474f5e3ea09dd..395dbcbc1055e 100644
--- a/server/src/test/java/org/opensearch/cluster/serialization/DiffableTests.java
+++ b/server/src/test/java/org/opensearch/cluster/serialization/DiffableTests.java
@@ -36,12 +36,10 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.DiffableUtils.MapDiff;
-import org.opensearch.common.collect.ImmutableOpenIntMap;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -106,106 +104,6 @@ protected MapDiff readDiff(StreamInput in) throws IOException {
         }.execute();
     }
 
-    public void testImmutableOpenMapDiff() throws IOException {
-        new ImmutableOpenMapDriver<TestDiffable>() {
-            @Override
-            protected boolean diffableValues() {
-                return true;
-            }
-
-            @Override
-            protected TestDiffable createValue(Integer key, boolean before) {
-                return new TestDiffable(String.valueOf(before ? key : key + 1));
-            }
-
-            @Override
-            protected MapDiff diff(ImmutableOpenMap<Integer, TestDiffable> before, ImmutableOpenMap<Integer, TestDiffable> after) {
-                return DiffableUtils.diff(before, after, keySerializer);
-            }
-
-            @Override
-            protected MapDiff readDiff(StreamInput in) throws IOException {
-                return useProtoForDiffableSerialization
-                    ? DiffableUtils.readImmutableOpenMapDiff(
-                        in,
-                        keySerializer,
-                        new DiffableUtils.DiffableValueReader<>(TestDiffable::readFrom, TestDiffable::readDiffFrom)
-                    )
-                    : DiffableUtils.readImmutableOpenMapDiff(in, keySerializer, diffableValueSerializer());
-            }
-        }.execute();
-
-        new ImmutableOpenMapDriver<String>() {
-            @Override
-            protected boolean diffableValues() {
-                return false;
-            }
-
-            @Override
-            protected String createValue(Integer key, boolean before) {
-                return String.valueOf(before ? key : key + 1);
-            }
-
-            @Override
-            protected MapDiff diff(ImmutableOpenMap<Integer, String> before, ImmutableOpenMap<Integer, String> after) {
-                return DiffableUtils.diff(before, after, keySerializer, nonDiffableValueSerializer());
-            }
-
-            @Override
-            protected MapDiff readDiff(StreamInput in) throws IOException {
-                return DiffableUtils.readImmutableOpenMapDiff(in, keySerializer, nonDiffableValueSerializer());
-            }
-        }.execute();
-    }
-
-    public void testImmutableOpenIntMapDiff() throws IOException {
-        new ImmutableOpenIntMapDriver<TestDiffable>() {
-            @Override
-            protected boolean diffableValues() {
-                return true;
-            }
-
-            @Override
-            protected TestDiffable createValue(Integer key, boolean before) {
-                return new TestDiffable(String.valueOf(before ? key : key + 1));
-            }
-
-            @Override
-            protected MapDiff diff(ImmutableOpenIntMap<TestDiffable> before, ImmutableOpenIntMap<TestDiffable> after) {
-                return DiffableUtils.diff(before, after, keySerializer);
-            }
-
-            @Override
-            protected MapDiff readDiff(StreamInput in) throws IOException {
-                return useProtoForDiffableSerialization
-                    ? DiffableUtils.readImmutableOpenIntMapDiff(in, keySerializer, TestDiffable::readFrom, TestDiffable::readDiffFrom)
-                    : DiffableUtils.readImmutableOpenIntMapDiff(in, keySerializer, diffableValueSerializer());
-            }
-        }.execute();
-
-        new ImmutableOpenIntMapDriver<String>() {
-            @Override
-            protected boolean diffableValues() {
-                return false;
-            }
-
-            @Override
-            protected String createValue(Integer key, boolean before) {
-                return String.valueOf(before ? key : key + 1);
-            }
-
-            @Override
-            protected MapDiff diff(ImmutableOpenIntMap<String> before, ImmutableOpenIntMap<String> after) {
-                return DiffableUtils.diff(before, after, keySerializer, nonDiffableValueSerializer());
-            }
-
-            @Override
-            protected MapDiff readDiff(StreamInput in) throws IOException {
-                return DiffableUtils.readImmutableOpenIntMapDiff(in, keySerializer, nonDiffableValueSerializer());
-            }
-        }.execute();
-    }
-
     /**
      * Class that abstracts over specific map implementation type and value kind (Diffable or not)
      * @param <T> map type
@@ -374,42 +272,6 @@ protected int size(Map<Integer, V> map) {
         }
     }
 
-    abstract class ImmutableOpenMapDriver<V> extends MapDriver<ImmutableOpenMap<Integer, V>, V> {
-
-        @Override
-        protected ImmutableOpenMap<Integer, V> createMap(Map values) {
-            return ImmutableOpenMap.<Integer, V>builder().putAll(values).build();
-        }
-
-        @Override
-        protected V get(ImmutableOpenMap<Integer, V> map, Integer key) {
-            return map.get(key);
-        }
-
-        @Override
-        protected int size(ImmutableOpenMap<Integer, V> map) {
-            return map.size();
-        }
-    }
-
-    abstract class ImmutableOpenIntMapDriver<V> extends MapDriver<ImmutableOpenIntMap<V>, V> {
-
-        @Override
-        protected ImmutableOpenIntMap<V> createMap(Map values) {
-            return ImmutableOpenIntMap.<V>builder().putAll(values).build();
-        }
-
-        @Override
-        protected V get(ImmutableOpenIntMap<V> map, Integer key) {
-            return map.get(key);
-        }
-
-        @Override
-        protected int size(ImmutableOpenIntMap<V> map) {
-            return map.size();
-        }
-    }
-
     private static <K> DiffableUtils.DiffableValueSerializer<K, TestDiffable> diffableValueSerializer() {
         return new DiffableUtils.DiffableValueSerializer<K, TestDiffable>() {
             @Override
diff --git a/server/src/test/java/org/opensearch/cluster/service/ClusterApplierServiceTests.java b/server/src/test/java/org/opensearch/cluster/service/ClusterApplierServiceTests.java
index b3c24ef55c3ba..c5ed505e6bbf2 100644
--- a/server/src/test/java/org/opensearch/cluster/service/ClusterApplierServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/service/ClusterApplierServiceTests.java
@@ -38,9 +38,10 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateObserver;
+import org.opensearch.cluster.LocalNodeClusterManagerListener;
 import org.opensearch.cluster.LocalNodeMasterListener;
 import org.opensearch.cluster.block.ClusterBlocks;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -50,8 +51,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -104,7 +105,7 @@ public void tearDown() throws Exception {
         super.tearDown();
     }
 
-    private TimedClusterApplierService createTimedClusterService(boolean makeMaster) {
+    private TimedClusterApplierService createTimedClusterService(boolean makeClusterManager) {
         DiscoveryNode localNode = new DiscoveryNode("node1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         TimedClusterApplierService timedClusterApplierService = new TimedClusterApplierService(
             Settings.builder().put("cluster.name", "ClusterApplierServiceTests").build(),
@@ -118,7 +119,7 @@ private TimedClusterApplierService createTimedClusterService(boolean makeMaster)
                     DiscoveryNodes.builder()
                         .add(localNode)
                         .localNodeId(localNode.getId())
-                        .masterNodeId(makeMaster ? localNode.getId() : null)
+                        .clusterManagerNodeId(makeClusterManager ? localNode.getId() : null)
                 )
                 .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
                 .build()
@@ -292,41 +293,78 @@ public void onFailure(String source, Exception e) {
         }
     }
 
-    public void testLocalNodeMasterListenerCallbacks() {
+    public void testLocalNodeClusterManagerListenerCallbacks() {
         TimedClusterApplierService timedClusterApplierService = createTimedClusterService(false);
 
-        AtomicBoolean isMaster = new AtomicBoolean();
-        timedClusterApplierService.addLocalNodeMasterListener(new LocalNodeMasterListener() {
+        AtomicBoolean isClusterManager = new AtomicBoolean();
+        timedClusterApplierService.addLocalNodeClusterManagerListener(new LocalNodeClusterManagerListener() {
             @Override
-            public void onMaster() {
-                isMaster.set(true);
+            public void onClusterManager() {
+                isClusterManager.set(true);
             }
 
             @Override
-            public void offMaster() {
-                isMaster.set(false);
+            public void offClusterManager() {
+                isClusterManager.set(false);
             }
         });
 
         ClusterState state = timedClusterApplierService.state();
         DiscoveryNodes nodes = state.nodes();
-        DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(nodes).masterNodeId(nodes.getLocalNodeId());
+        DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(nodes).clusterManagerNodeId(nodes.getLocalNodeId());
         state = ClusterState.builder(state).blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK).nodes(nodesBuilder).build();
         setState(timedClusterApplierService, state);
-        assertThat(isMaster.get(), is(true));
+        assertThat(isClusterManager.get(), is(true));
 
         nodes = state.nodes();
-        nodesBuilder = DiscoveryNodes.builder(nodes).masterNodeId(null);
+        nodesBuilder = DiscoveryNodes.builder(nodes).clusterManagerNodeId(null);
         state = ClusterState.builder(state)
-            .blocks(ClusterBlocks.builder().addGlobalBlock(NoMasterBlockService.NO_MASTER_BLOCK_WRITES))
+            .blocks(ClusterBlocks.builder().addGlobalBlock(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES))
             .nodes(nodesBuilder)
             .build();
         setState(timedClusterApplierService, state);
-        assertThat(isMaster.get(), is(false));
-        nodesBuilder = DiscoveryNodes.builder(nodes).masterNodeId(nodes.getLocalNodeId());
+        assertThat(isClusterManager.get(), is(false));
+        nodesBuilder = DiscoveryNodes.builder(nodes).clusterManagerNodeId(nodes.getLocalNodeId());
         state = ClusterState.builder(state).blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK).nodes(nodesBuilder).build();
         setState(timedClusterApplierService, state);
-        assertThat(isMaster.get(), is(true));
+        assertThat(isClusterManager.get(), is(true));
+
+        timedClusterApplierService.close();
+    }
+
+    /* Validate the backwards compatibility of LocalNodeMasterListener remains
+     * after making it a subclass of LocalNodeClusterManagerListener.
+     * Overriding the methods with non-inclusive words are intentional.
+     * To support inclusive language, LocalNodeMasterListener is deprecated in 2.2.
+     */
+    public void testDeprecatedLocalNodeMasterListenerCallbacks() {
+        TimedClusterApplierService timedClusterApplierService = createTimedClusterService(false);
+
+        AtomicBoolean isClusterManager = new AtomicBoolean();
+        timedClusterApplierService.addLocalNodeMasterListener(new LocalNodeMasterListener() {
+            @Override
+            public void onMaster() {
+                isClusterManager.set(true);
+            }
+
+            @Override
+            public void offMaster() {
+                isClusterManager.set(false);
+            }
+        });
+
+        ClusterState state = timedClusterApplierService.state();
+        DiscoveryNodes nodes = state.nodes();
+        DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(nodes).masterNodeId(nodes.getLocalNodeId());
+        state = ClusterState.builder(state).nodes(nodesBuilder).build();
+        setState(timedClusterApplierService, state);
+        assertThat(isClusterManager.get(), is(true));
+
+        nodes = state.nodes();
+        nodesBuilder = DiscoveryNodes.builder(nodes).masterNodeId(null);
+        state = ClusterState.builder(state).nodes(nodesBuilder).build();
+        setState(timedClusterApplierService, state);
+        assertThat(isClusterManager.get(), is(false));
 
         timedClusterApplierService.close();
     }
diff --git a/server/src/test/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerTests.java b/server/src/test/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerTests.java
new file mode 100644
index 0000000000000..e25a0e0b2c3bf
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/service/ClusterManagerTaskThrottlerTests.java
@@ -0,0 +1,462 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.Version;
+import org.opensearch.action.support.replication.ClusterStateCreationUtils;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateTaskExecutor;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.Priority;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.test.ClusterServiceUtils.setState;
+
+/**
+ * Contains tests for {@link ClusterManagerTaskThrottler}
+ */
+public class ClusterManagerTaskThrottlerTests extends OpenSearchTestCase {
+
+    private static ThreadPool threadPool;
+    private ClusterService clusterService;
+
+    @BeforeClass
+    public static void beforeClass() {
+        threadPool = new TestThreadPool("TransportMasterNodeActionTests");
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        clusterService = ClusterServiceUtils.createClusterService(threadPool);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        clusterService.close();
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+        threadPool = null;
+    }
+
+    public void testDefaults() {
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+        throttler.registerClusterManagerTask("create-index", true);
+        for (String key : throttler.THROTTLING_TASK_KEYS.keySet()) {
+            assertNull(throttler.getThrottlingLimit(key));
+        }
+    }
+
+    public void testValidateSettingsForDifferentVersion() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_0_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        // set some limit for update snapshot tasks
+        int newLimit = randomIntBetween(1, 10);
+
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", newLimit).build();
+        assertThrows(IllegalArgumentException.class, () -> throttler.validateSetting(newSettings));
+
+        // validate for empty setting, it shouldn't throw exception
+        Settings emptySettings = Settings.builder().build();
+        try {
+            throttler.validateSetting(emptySettings);
+        } catch (Exception e) {
+            // it shouldn't throw exception
+            throw new AssertionError(e);
+        }
+    }
+
+    public void testValidateSettingsForTaskWihtoutRetryOnDataNode() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", false);
+
+        // set some limit for update snapshot tasks
+        int newLimit = randomIntBetween(1, 10);
+
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", newLimit).build();
+        assertThrows(IllegalArgumentException.class, () -> throttler.validateSetting(newSettings));
+    }
+
+    public void testUpdateSettingsForNullValue() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        // set some limit for put-mapping tasks
+        int newLimit = randomIntBetween(1, 10);
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", newLimit).build();
+        clusterSettings.applySettings(newSettings);
+        assertEquals(newLimit, throttler.getThrottlingLimit("put-mapping").intValue());
+
+        // set limit to null
+        Settings nullSettings = Settings.builder().build();
+        clusterSettings.applySettings(nullSettings);
+        assertNull(throttler.getThrottlingLimit("put-mapping"));
+    }
+
+    public void testSettingsOnBootstrap() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        int put_mapping_threshold_value = randomIntBetween(1, 10);
+        int baseDelay = randomIntBetween(1, 10);
+        int maxDelay = randomIntBetween(1, 10);
+        Settings initialSettings = Settings.builder()
+            .put("cluster_manager.throttling.thresholds.put-mapping.value", put_mapping_threshold_value)
+            .put("cluster_manager.throttling.retry.base.delay", baseDelay + "s")
+            .put("cluster_manager.throttling.retry.max.delay", maxDelay + "s")
+            .build();
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(initialSettings, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        // assert that limit is applied on throttler
+        assertEquals(put_mapping_threshold_value, throttler.getThrottlingLimit("put-mapping").intValue());
+        // assert that delay setting is applied on throttler
+        assertEquals(baseDelay, ClusterManagerTaskThrottler.getBaseDelayForRetry().seconds());
+        assertEquals(maxDelay, ClusterManagerTaskThrottler.getMaxDelayForRetry().seconds());
+    }
+
+    public void testUpdateRetryDelaySetting() {
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+
+        // verify defaults
+        assertEquals(ClusterManagerTaskThrottler.baseDelay, ClusterManagerTaskThrottler.getBaseDelayForRetry());
+        assertEquals(ClusterManagerTaskThrottler.maxDelay, ClusterManagerTaskThrottler.getMaxDelayForRetry());
+
+        // verify update base delay
+        int baseDelay = randomIntBetween(1, 10);
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.retry.base.delay", baseDelay + "s").build();
+        clusterSettings.applySettings(newSettings);
+        assertEquals(baseDelay, ClusterManagerTaskThrottler.getBaseDelayForRetry().seconds());
+
+        // verify update max delay
+        int maxDelay = randomIntBetween(1, 10);
+        newSettings = Settings.builder().put("cluster_manager.throttling.retry.max.delay", maxDelay + "s").build();
+        clusterSettings.applySettings(newSettings);
+        assertEquals(maxDelay, ClusterManagerTaskThrottler.getMaxDelayForRetry().seconds());
+    }
+
+    public void testValidateSettingsForUnknownTask() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+
+        // set some limit for update snapshot tasks
+        int newLimit = randomIntBetween(1, 10);
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.random-task.value", newLimit).build();
+        assertThrows(IllegalArgumentException.class, () -> throttler.validateSetting(newSettings));
+    }
+
+    public void testUpdateThrottlingLimitForBasicSanity() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        // set some limit for update snapshot tasks
+        long newLimit = randomLongBetween(1, 10);
+
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", newLimit).build();
+        clusterSettings.applySettings(newSettings);
+        assertEquals(newLimit, throttler.getThrottlingLimit("put-mapping").intValue());
+
+        // set update snapshot task limit to default
+        newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.value", -1).build();
+        clusterSettings.applySettings(newSettings);
+        assertNull(throttler.getThrottlingLimit("put-mapping"));
+    }
+
+    public void testValidateSettingForLimit() {
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_5_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        Settings newSettings = Settings.builder().put("cluster_manager.throttling.thresholds.put-mapping.values", -5).build();
+        assertThrows(IllegalArgumentException.class, () -> throttler.validateSetting(newSettings));
+    }
+
+    public void testUpdateLimit() {
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, new ClusterManagerThrottlingStats());
+        throttler.registerClusterManagerTask("put-mapping", true);
+
+        throttler.updateLimit("test", 5);
+        assertEquals(5L, throttler.getThrottlingLimit("test").intValue());
+        throttler.updateLimit("test", -1);
+        assertNull(throttler.getThrottlingLimit("test"));
+    }
+
+    private DiscoveryNode getDataNode(Version version) {
+        return new DiscoveryNode(
+            "local_data_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.DATA_ROLE),
+            version
+        );
+    }
+
+    private DiscoveryNode getClusterManagerNode(Version version) {
+        return new DiscoveryNode(
+            "local_master_node",
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            version
+        );
+    }
+
+    public void testThrottlingForDisabledThrottlingTask() {
+        ClusterManagerThrottlingStats throttlingStats = new ClusterManagerThrottlingStats();
+        String taskKey = "test";
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, throttlingStats);
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey = throttler.registerClusterManagerTask(taskKey, false);
+
+        // adding limit directly in thresholds
+        throttler.updateLimit(taskKey, 5);
+
+        // adding 10 tasks, should pass as throttling is disabled for task
+        throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 10));
+
+        // Asserting that there was not any throttling for it
+        assertEquals(0L, throttlingStats.getThrottlingCount(taskKey));
+    }
+
+    public void testThrottlingForInitialStaticSettingAndVersionCheck() {
+        ClusterManagerThrottlingStats throttlingStats = new ClusterManagerThrottlingStats();
+        DiscoveryNode clusterManagerNode = getClusterManagerNode(Version.V_2_5_0);
+        DiscoveryNode dataNode = getDataNode(Version.V_2_4_0);
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode, dataNode })
+        );
+
+        // setting threshold in initial settings
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        int put_mapping_threshold_value = randomIntBetween(1, 10);
+        Settings initialSettings = Settings.builder()
+            .put("cluster_manager.throttling.thresholds.put-mapping.value", put_mapping_threshold_value)
+            .build();
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(initialSettings, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, throttlingStats);
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey = throttler.registerClusterManagerTask("put-mapping", true);
+
+        // verifying adding more tasks then threshold passes
+        throttler.onBeginSubmit(getMockUpdateTaskList("put-mapping", throttlingKey, put_mapping_threshold_value + 5));
+        assertEquals(0L, throttlingStats.getThrottlingCount("put-mapping"));
+
+        // Removing older version node from cluster
+        setState(
+            clusterService,
+            ClusterStateCreationUtils.state(clusterManagerNode, clusterManagerNode, new DiscoveryNode[] { clusterManagerNode })
+        );
+
+        // adding more tasks, these tasks should be throttled
+        // As queue already have more tasks than threshold from previous call.
+        assertThrows(
+            ClusterManagerThrottlingException.class,
+            () -> throttler.onBeginSubmit(getMockUpdateTaskList("put-mapping", throttlingKey, 3))
+        );
+        assertEquals(3L, throttlingStats.getThrottlingCount("put-mapping"));
+    }
+
+    public void testThrottling() {
+        ClusterManagerThrottlingStats throttlingStats = new ClusterManagerThrottlingStats();
+        String taskKey = "test";
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.builder().build(), ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        ClusterManagerTaskThrottler throttler = new ClusterManagerTaskThrottler(Settings.EMPTY, clusterSettings, () -> {
+            return clusterService.getMasterService().getMinNodeVersion();
+        }, throttlingStats);
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey = throttler.registerClusterManagerTask(taskKey, true);
+
+        throttler.updateLimit(taskKey, 5);
+
+        // adding 3 tasks
+        throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 3));
+
+        // adding 3 more tasks, these tasks should be throttled
+        // taskCount in Queue: 3 Threshold: 5
+        assertThrows(
+            ClusterManagerThrottlingException.class,
+            () -> throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 3))
+        );
+        assertEquals(3L, throttlingStats.getThrottlingCount(taskKey));
+
+        // remove one task
+        throttler.onBeginProcessing(getMockUpdateTaskList(taskKey, throttlingKey, 1));
+
+        // add 3 tasks should pass now.
+        // taskCount in Queue: 2 Threshold: 5
+        throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 3));
+
+        // adding one task will throttle
+        // taskCount in Queue: 5 Threshold: 5
+        assertThrows(
+            ClusterManagerThrottlingException.class,
+            () -> throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 1))
+        );
+        assertEquals(4L, throttlingStats.getThrottlingCount(taskKey));
+
+        // update limit of threshold 6
+        throttler.updateLimit(taskKey, 6);
+
+        // adding one task should pass now
+        throttler.onBeginSubmit(getMockUpdateTaskList(taskKey, throttlingKey, 1));
+    }
+
+    private List<TaskBatcherTests.TestTaskBatcher.UpdateTask> getMockUpdateTaskList(
+        String taskKey,
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey,
+        int size
+    ) {
+        TaskBatcherTests.TestTaskBatcher testTaskBatcher = new TaskBatcherTests.TestTaskBatcher(logger, null);
+        List<TaskBatcherTests.TestTaskBatcher.UpdateTask> taskList = new ArrayList<>();
+
+        class MockExecutor
+            implements
+                TaskExecutorTests.TestExecutor,
+                ClusterStateTaskExecutor<TaskBatcherTests.TestTaskBatcher.UpdateTask> {
+
+            @Override
+            public ClusterTasksResult<TaskBatcherTests.TestTaskBatcher.UpdateTask> execute(
+                ClusterState currentState,
+                List<TaskBatcherTests.TestTaskBatcher.UpdateTask> tasks
+            ) throws Exception {
+                // No Op
+                return null;
+            }
+
+            @Override
+            public boolean runOnlyOnMaster() {
+                return true;
+            }
+
+            @Override
+            public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {}
+
+            @Override
+            public void execute(List tasks) {}
+
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return throttlingKey;
+            }
+
+            @Override
+            public String describeTasks(List tasks) {
+                return taskKey;
+            }
+        }
+
+        for (int i = 0; i < size; i++) {
+            taskList.add(testTaskBatcher.new UpdateTask(Priority.HIGH, taskKey, taskKey, (source, e) -> {
+                if (!(e instanceof ClusterManagerThrottlingException)) {
+                    throw new AssertionError(e);
+                }
+            }, new MockExecutor()));
+        }
+        return taskList;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/service/ClusterManagerThrottlingStatsTests.java b/server/src/test/java/org/opensearch/cluster/service/ClusterManagerThrottlingStatsTests.java
new file mode 100644
index 0000000000000..0f8d8ee915c45
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/service/ClusterManagerThrottlingStatsTests.java
@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+public class ClusterManagerThrottlingStatsTests extends AbstractWireSerializingTestCase<ClusterManagerThrottlingStats> {
+    @Override
+    protected Writeable.Reader<ClusterManagerThrottlingStats> instanceReader() {
+        return ClusterManagerThrottlingStats::new;
+    }
+
+    @Override
+    protected ClusterManagerThrottlingStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static ClusterManagerThrottlingStats randomInstance() {
+        ClusterManagerThrottlingStats randomStats = new ClusterManagerThrottlingStats();
+        randomStats.onThrottle(randomAlphaOfLengthBetween(3, 10), randomInt());
+        return randomStats;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/service/ClusterServiceTests.java b/server/src/test/java/org/opensearch/cluster/service/ClusterServiceTests.java
new file mode 100644
index 0000000000000..4d88683826af7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/cluster/service/ClusterServiceTests.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.junit.After;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class ClusterServiceTests extends OpenSearchTestCase {
+    private final TestThreadPool threadPool = new TestThreadPool(ClusterServiceTests.class.getName());
+
+    @After
+    public void terminateThreadPool() {
+        terminate(threadPool);
+    }
+
+    public void testDeprecatedGetMasterServiceBWC() {
+        try (
+            ClusterService clusterService = new ClusterService(
+                Settings.EMPTY,
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                threadPool
+            )
+        ) {
+            MasterService masterService = clusterService.getMasterService();
+            ClusterManagerService clusterManagerService = clusterService.getClusterManagerService();
+            assertThat(masterService, equalTo(clusterManagerService));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/cluster/service/MasterServiceTests.java b/server/src/test/java/org/opensearch/cluster/service/MasterServiceTests.java
index 845a5ee91052d..9cdbe04e0a0e4 100644
--- a/server/src/test/java/org/opensearch/cluster/service/MasterServiceTests.java
+++ b/server/src/test/java/org/opensearch/cluster/service/MasterServiceTests.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.cluster.service;
 
+import com.carrotsearch.randomizedtesting.annotations.Timeout;
+
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.OpenSearchException;
@@ -59,8 +61,8 @@
 import org.opensearch.common.util.concurrent.BaseFuture;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.node.Node;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -92,18 +94,19 @@
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasKey;
+import static org.hamcrest.Matchers.is;
 
 public class MasterServiceTests extends OpenSearchTestCase {
 
     private static ThreadPool threadPool;
-    private static long relativeTimeInMillis;
+    private static long timeDiffInMillis;
 
     @BeforeClass
     public static void createThreadPool() {
         threadPool = new TestThreadPool(MasterServiceTests.class.getName()) {
             @Override
-            public long relativeTimeInMillis() {
-                return relativeTimeInMillis;
+            public long preciseRelativeTimeInNanos() {
+                return timeDiffInMillis * TimeValue.NSEC_PER_MSEC;
             }
         };
     }
@@ -118,12 +121,12 @@ public static void stopThreadPool() {
 
     @Before
     public void randomizeCurrentTime() {
-        relativeTimeInMillis = randomLongBetween(0L, 1L << 62);
+        timeDiffInMillis = randomLongBetween(0L, 1L << 50);
     }
 
-    private MasterService createMasterService(boolean makeMaster) {
+    private ClusterManagerService createClusterManagerService(boolean makeClusterManager) {
         final DiscoveryNode localNode = new DiscoveryNode("node1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
-        final MasterService masterService = new MasterService(
+        final ClusterManagerService clusterManagerService = new ClusterManagerService(
             Settings.builder()
                 .put(ClusterName.CLUSTER_NAME_SETTING.getKey(), MasterServiceTests.class.getSimpleName())
                 .put(Node.NODE_NAME_SETTING.getKey(), "test_node")
@@ -133,26 +136,29 @@ private MasterService createMasterService(boolean makeMaster) {
         );
         final ClusterState initialClusterState = ClusterState.builder(new ClusterName(MasterServiceTests.class.getSimpleName()))
             .nodes(
-                DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).masterNodeId(makeMaster ? localNode.getId() : null)
+                DiscoveryNodes.builder()
+                    .add(localNode)
+                    .localNodeId(localNode.getId())
+                    .clusterManagerNodeId(makeClusterManager ? localNode.getId() : null)
             )
             .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
             .build();
         final AtomicReference<ClusterState> clusterStateRef = new AtomicReference<>(initialClusterState);
-        masterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+        clusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
             clusterStateRef.set(event.state());
             publishListener.onResponse(null);
         });
-        masterService.setClusterStateSupplier(clusterStateRef::get);
-        masterService.start();
-        return masterService;
+        clusterManagerService.setClusterStateSupplier(clusterStateRef::get);
+        clusterManagerService.start();
+        return clusterManagerService;
     }
 
-    public void testMasterAwareExecution() throws Exception {
-        final MasterService nonMaster = createMasterService(false);
+    public void testClusterManagerAwareExecution() throws Exception {
+        final ClusterManagerService nonClusterManager = createClusterManagerService(false);
 
         final boolean[] taskFailed = { false };
         final CountDownLatch latch1 = new CountDownLatch(1);
-        nonMaster.submitStateUpdateTask("test", new ClusterStateUpdateTask() {
+        nonClusterManager.submitStateUpdateTask("test", new ClusterStateUpdateTask() {
             @Override
             public ClusterState execute(ClusterState currentState) {
                 latch1.countDown();
@@ -167,10 +173,10 @@ public void onFailure(String source, Exception e) {
         });
 
         latch1.await();
-        assertTrue("cluster state update task was executed on a non-master", taskFailed[0]);
+        assertTrue("cluster state update task was executed on a non-cluster-manager", taskFailed[0]);
 
         final CountDownLatch latch2 = new CountDownLatch(1);
-        nonMaster.submitStateUpdateTask("test", new LocalClusterUpdateTask() {
+        nonClusterManager.submitStateUpdateTask("test", new LocalClusterUpdateTask() {
             @Override
             public ClusterTasksResult<LocalClusterUpdateTask> execute(ClusterState currentState) {
                 taskFailed[0] = false;
@@ -185,13 +191,13 @@ public void onFailure(String source, Exception e) {
             }
         });
         latch2.await();
-        assertFalse("non-master cluster state update task was not executed", taskFailed[0]);
+        assertFalse("non-cluster-manager cluster state update task was not executed", taskFailed[0]);
 
-        nonMaster.close();
+        nonClusterManager.close();
     }
 
     public void testThreadContext() throws InterruptedException {
-        final MasterService master = createMasterService(true);
+        final ClusterManagerService clusterManagerService = createClusterManagerService(true);
         final CountDownLatch latch = new CountDownLatch(1);
 
         try (ThreadContext.StoredContext ignored = threadPool.getThreadContext().stashContext()) {
@@ -203,9 +209,9 @@ public void testThreadContext() throws InterruptedException {
             threadPool.getThreadContext().putHeader(expectedHeaders);
 
             final TimeValue ackTimeout = randomBoolean() ? TimeValue.ZERO : TimeValue.timeValueMillis(randomInt(10000));
-            final TimeValue masterTimeout = randomBoolean() ? TimeValue.ZERO : TimeValue.timeValueMillis(randomInt(10000));
+            final TimeValue clusterManagerTimeout = randomBoolean() ? TimeValue.ZERO : TimeValue.timeValueMillis(randomInt(10000));
 
-            master.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
+            clusterManagerService.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
                 @Override
                 public ClusterState execute(ClusterState currentState) {
                     assertTrue(threadPool.getThreadContext().isSystemContext());
@@ -249,7 +255,7 @@ public TimeValue ackTimeout() {
 
                 @Override
                 public TimeValue timeout() {
-                    return masterTimeout;
+                    return clusterManagerTimeout;
                 }
 
                 @Override
@@ -277,7 +283,7 @@ public void onAckTimeout() {
 
         latch.await();
 
-        master.close();
+        clusterManagerService.close();
     }
 
     /*
@@ -289,8 +295,8 @@ public void testClusterStateTaskListenerThrowingExceptionIsOkay() throws Interru
         final CountDownLatch latch = new CountDownLatch(1);
         AtomicBoolean published = new AtomicBoolean();
 
-        try (MasterService masterService = createMasterService(true)) {
-            masterService.submitStateUpdateTask(
+        try (ClusterManagerService clusterManagerService = createClusterManagerService(true)) {
+            clusterManagerService.submitStateUpdateTask(
                 "testClusterStateTaskListenerThrowingExceptionIsOkay",
                 new Object(),
                 ClusterStateTaskConfig.build(Priority.NORMAL),
@@ -418,11 +424,11 @@ public void testClusterStateUpdateLogging() throws Exception {
                 )
             );
 
-            try (MasterService masterService = createMasterService(true)) {
-                masterService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
+            try (ClusterManagerService clusterManagerService = createClusterManagerService(true)) {
+                clusterManagerService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += TimeValue.timeValueSeconds(1).millis();
+                        timeDiffInMillis += TimeValue.timeValueSeconds(1).millis();
                         return currentState;
                     }
 
@@ -434,10 +440,10 @@ public void onFailure(String source, Exception e) {
                         fail();
                     }
                 });
-                masterService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += TimeValue.timeValueSeconds(2).millis();
+                        timeDiffInMillis += TimeValue.timeValueSeconds(2).millis();
                         throw new IllegalArgumentException("Testing handling of exceptions in the cluster state task");
                     }
 
@@ -449,16 +455,16 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                     @Override
                     public void onFailure(String source, Exception e) {}
                 });
-                masterService.submitStateUpdateTask("test3", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test3", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += TimeValue.timeValueSeconds(3).millis();
+                        timeDiffInMillis += TimeValue.timeValueSeconds(3).millis();
                         return ClusterState.builder(currentState).incrementVersion().build();
                     }
 
                     @Override
                     public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
-                        relativeTimeInMillis += TimeValue.timeValueSeconds(4).millis();
+                        timeDiffInMillis += TimeValue.timeValueSeconds(4).millis();
                     }
 
                     @Override
@@ -466,7 +472,7 @@ public void onFailure(String source, Exception e) {
                         fail();
                     }
                 });
-                masterService.submitStateUpdateTask("test4", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test4", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return currentState;
@@ -614,7 +620,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
             }
         };
 
-        try (MasterService masterService = createMasterService(true)) {
+        try (ClusterManagerService clusterManagerService = createClusterManagerService(true)) {
             final ConcurrentMap<String, AtomicInteger> submittedTasksPerThread = new ConcurrentHashMap<>();
             CyclicBarrier barrier = new CyclicBarrier(1 + numberOfThreads);
             for (int i = 0; i < numberOfThreads; i++) {
@@ -629,7 +635,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                             submittedTasksPerThread.computeIfAbsent(threadName, key -> new AtomicInteger()).addAndGet(tasks.size());
                             final TaskExecutor executor = assignment.v1();
                             if (tasks.size() == 1) {
-                                masterService.submitStateUpdateTask(
+                                clusterManagerService.submitStateUpdateTask(
                                     threadName,
                                     tasks.stream().findFirst().get(),
                                     ClusterStateTaskConfig.build(randomFrom(Priority.values())),
@@ -639,7 +645,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                             } else {
                                 Map<Task, ClusterStateTaskListener> taskListeners = new HashMap<>();
                                 tasks.forEach(t -> taskListeners.put(t, listener));
-                                masterService.submitStateUpdateTasks(
+                                clusterManagerService.submitStateUpdateTasks(
                                     threadName,
                                     taskListeners,
                                     ClusterStateTaskConfig.build(randomFrom(Priority.values())),
@@ -688,13 +694,283 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
         }
     }
 
+    public void testThrottlingForTaskSubmission() throws InterruptedException {
+        MasterService masterService = createClusterManagerService(true);
+        int throttlingLimit = randomIntBetween(1, 10);
+        int taskId = 1;
+        final CyclicBarrier barrier = new CyclicBarrier(2);
+        final CountDownLatch latch = new CountDownLatch(1);
+        final String taskName = "test";
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey = masterService.registerClusterManagerTask(taskName, true);
+        class Task {
+            private final int id;
+
+            Task(int id) {
+                this.id = id;
+            }
+        }
+
+        class TaskExecutor implements ClusterStateTaskExecutor<Task> {
+            private AtomicInteger published = new AtomicInteger();
+
+            @Override
+            public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> tasks) throws Exception {
+                latch.countDown();
+                barrier.await();
+                return ClusterTasksResult.<Task>builder().successes(tasks).build(currentState);
+            }
+
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return throttlingKey;
+            }
+
+            @Override
+            public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {
+                published.incrementAndGet();
+            }
+        }
+
+        masterService.clusterManagerTaskThrottler.updateLimit(taskName, throttlingLimit);
+
+        final ClusterStateTaskListener listener = new ClusterStateTaskListener() {
+            @Override
+            public void onFailure(String source, Exception e) {}
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {}
+        };
+
+        TaskExecutor executor = new TaskExecutor();
+        // submit one task which will be execution, post that will submit throttlingLimit tasks.
+        try {
+            masterService.submitStateUpdateTask(
+                taskName,
+                new Task(taskId++),
+                ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                executor,
+                listener
+            );
+        } catch (Exception e) {
+            throw new AssertionError(e);
+        }
+        // wait till task enter in execution.
+        latch.await();
+
+        for (int i = 0; i < throttlingLimit; i++) {
+            try {
+                masterService.submitStateUpdateTask(
+                    taskName,
+                    new Task(taskId++),
+                    ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                    executor,
+                    listener
+                );
+            } catch (Exception e) {
+                throw new AssertionError(e);
+            }
+        }
+
+        // we have one task in execution and tasks in queue so next task should throttled.
+        final AtomicReference<ClusterManagerThrottlingException> assertionRef = new AtomicReference<>();
+        try {
+            masterService.submitStateUpdateTask(
+                taskName,
+                new Task(taskId++),
+                ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                executor,
+                listener
+            );
+        } catch (ClusterManagerThrottlingException e) {
+            assertionRef.set(e);
+        }
+        assertNotNull(assertionRef.get());
+        masterService.close();
+    }
+
+    public void testThrottlingForMultipleTaskTypes() throws InterruptedException {
+        MasterService masterService = createClusterManagerService(true);
+        int throttlingLimitForTask1 = randomIntBetween(1, 5);
+        int throttlingLimitForTask2 = randomIntBetween(1, 5);
+        int throttlingLimitForTask3 = randomIntBetween(1, 5);
+        int numberOfTask1 = randomIntBetween(throttlingLimitForTask1, 10);
+        int numberOfTask2 = randomIntBetween(throttlingLimitForTask2, 10);
+        int numberOfTask3 = randomIntBetween(throttlingLimitForTask3, 10);
+        String task1 = "Task1";
+        String task2 = "Task2";
+        String task3 = "Task3";
+
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey1 = masterService.registerClusterManagerTask(task1, true);
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey2 = masterService.registerClusterManagerTask(task2, true);
+        ClusterManagerTaskThrottler.ThrottlingKey throttlingKey3 = masterService.registerClusterManagerTask(task3, true);
+        class Task {}
+        class Task1 extends Task {}
+        class Task2 extends Task {}
+        class Task3 extends Task {}
+
+        class Task1Executor implements ClusterStateTaskExecutor<Task> {
+            @Override
+            public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> tasks) throws Exception {
+                Thread.sleep(randomInt(1000));
+                return ClusterTasksResult.<Task>builder().successes(tasks).build(currentState);
+            }
+
+            @Override
+            public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {}
+
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return throttlingKey1;
+            }
+        }
+
+        class Task2Executor implements ClusterStateTaskExecutor<Task> {
+            @Override
+            public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> tasks) throws Exception {
+                Thread.sleep(randomInt(1000));
+                return ClusterTasksResult.<Task>builder().successes(tasks).build(currentState);
+            }
+
+            @Override
+            public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {}
+
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return throttlingKey2;
+            }
+        }
+
+        class Task3Executor implements ClusterStateTaskExecutor<Task> {
+            @Override
+            public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> tasks) throws Exception {
+                Thread.sleep(randomInt(1000));
+                return ClusterTasksResult.<Task>builder().successes(tasks).build(currentState);
+            }
+
+            @Override
+            public void clusterStatePublished(ClusterChangedEvent clusterChangedEvent) {}
+
+            @Override
+            public ClusterManagerTaskThrottler.ThrottlingKey getClusterManagerThrottlingKey() {
+                return throttlingKey3;
+            }
+        }
+
+        // configuring limits for Task1 and Task3. All task submission of Task2 should pass.
+        masterService.clusterManagerTaskThrottler.updateLimit(task1, throttlingLimitForTask1);
+        masterService.clusterManagerTaskThrottler.updateLimit(task3, throttlingLimitForTask3);
+        final CountDownLatch latch = new CountDownLatch(numberOfTask1 + numberOfTask2 + numberOfTask3);
+        AtomicInteger throttledTask1 = new AtomicInteger();
+        AtomicInteger throttledTask2 = new AtomicInteger();
+        AtomicInteger throttledTask3 = new AtomicInteger();
+        AtomicInteger succeededTask1 = new AtomicInteger();
+        AtomicInteger succeededTask2 = new AtomicInteger();
+        AtomicInteger succeededTask3 = new AtomicInteger();
+        AtomicInteger timedOutTask3 = new AtomicInteger();
+
+        final ClusterStateTaskListener listener = new ClusterStateTaskListener() {
+            @Override
+            public void onFailure(String source, Exception e) {
+                // Task3's timeout should have called this.
+                assertEquals(task3, source);
+                timedOutTask3.incrementAndGet();
+                latch.countDown();
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                if (source.equals(task1)) {
+                    succeededTask1.incrementAndGet();
+                } else if (source.equals(task2)) {
+                    succeededTask2.incrementAndGet();
+                } else if (source.equals(task3)) {
+                    succeededTask3.incrementAndGet();
+                }
+                latch.countDown();
+            }
+        };
+        Task1Executor executor1 = new Task1Executor();
+        Task2Executor executor2 = new Task2Executor();
+        Task3Executor executor3 = new Task3Executor();
+        List<Thread> threads = new ArrayList<Thread>();
+        for (int i = 0; i < numberOfTask1; i++) {
+            threads.add(new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        masterService.submitStateUpdateTask(
+                            task1,
+                            new Task1(),
+                            ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                            executor1,
+                            listener
+                        );
+                    } catch (ClusterManagerThrottlingException e) {
+                        // Exception should be RejactedExecutionException.
+                        throttledTask1.incrementAndGet();
+                        latch.countDown();
+                    }
+                }
+            }));
+        }
+        for (int i = 0; i < numberOfTask2; i++) {
+            threads.add(new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        masterService.submitStateUpdateTask(
+                            task2,
+                            new Task2(),
+                            ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                            executor2,
+                            listener
+                        );
+                    } catch (ClusterManagerThrottlingException e) {
+                        throttledTask2.incrementAndGet();
+                        latch.countDown();
+                    }
+                }
+            }));
+        }
+        for (int i = 0; i < numberOfTask3; i++) {
+            threads.add(new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        masterService.submitStateUpdateTask(
+                            task3,
+                            new Task3(),
+                            ClusterStateTaskConfig.build(randomFrom(Priority.values()), new TimeValue(0)),
+                            executor3,
+                            listener
+                        );
+                    } catch (ClusterManagerThrottlingException e) {
+                        throttledTask3.incrementAndGet();
+                        latch.countDown();
+                    }
+                }
+            }));
+        }
+        for (Thread thread : threads) {
+            thread.start();
+        }
+
+        // await for latch to clear
+        latch.await();
+        assertEquals(numberOfTask1, throttledTask1.get() + succeededTask1.get());
+        assertEquals(numberOfTask2, succeededTask2.get());
+        assertEquals(0, throttledTask2.get());
+        assertEquals(numberOfTask3, throttledTask3.get() + timedOutTask3.get() + succeededTask3.get());
+        masterService.close();
+    }
+
     public void testBlockingCallInClusterStateTaskListenerFails() throws InterruptedException {
         assumeTrue("assertions must be enabled for this test to work", BaseFuture.class.desiredAssertionStatus());
         final CountDownLatch latch = new CountDownLatch(1);
         final AtomicReference<AssertionError> assertionRef = new AtomicReference<>();
 
-        try (MasterService masterService = createMasterService(true)) {
-            masterService.submitStateUpdateTask(
+        try (ClusterManagerService clusterManagerService = createClusterManagerService(true)) {
+            clusterManagerService.submitStateUpdateTask(
                 "testBlockingCallInClusterStateTaskListenerFails",
                 new Object(),
                 ClusterStateTaskConfig.build(Priority.NORMAL),
@@ -785,7 +1061,7 @@ public void testLongClusterStateUpdateLogging() throws Exception {
             );
 
             try (
-                MasterService masterService = new MasterService(
+                ClusterManagerService clusterManagerService = new ClusterManagerService(
                     Settings.builder()
                         .put(ClusterName.CLUSTER_NAME_SETTING.getKey(), MasterServiceTests.class.getSimpleName())
                         .put(Node.NODE_NAME_SETTING.getKey(), "test_node")
@@ -807,14 +1083,14 @@ public void testLongClusterStateUpdateLogging() throws Exception {
                     .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
                     .build();
                 final AtomicReference<ClusterState> clusterStateRef = new AtomicReference<>(initialClusterState);
-                masterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+                clusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
                     if (event.source().contains("test5")) {
-                        relativeTimeInMillis += MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
+                        timeDiffInMillis += ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
                             Settings.EMPTY
                         ).millis() + randomLongBetween(1, 1000000);
                     }
                     if (event.source().contains("test6")) {
-                        relativeTimeInMillis += MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
+                        timeDiffInMillis += ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
                             Settings.EMPTY
                         ).millis() + randomLongBetween(1, 1000000);
                         throw new OpenSearchException("simulated error during slow publication which should trigger logging");
@@ -822,17 +1098,17 @@ public void testLongClusterStateUpdateLogging() throws Exception {
                     clusterStateRef.set(event.state());
                     publishListener.onResponse(null);
                 });
-                masterService.setClusterStateSupplier(clusterStateRef::get);
-                masterService.start();
+                clusterManagerService.setClusterStateSupplier(clusterStateRef::get);
+                clusterManagerService.start();
 
                 final CountDownLatch latch = new CountDownLatch(6);
                 final CountDownLatch processedFirstTask = new CountDownLatch(1);
-                masterService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += randomLongBetween(
+                        timeDiffInMillis += randomLongBetween(
                             0L,
-                            MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(Settings.EMPTY).millis()
+                            ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(Settings.EMPTY).millis()
                         );
                         return currentState;
                     }
@@ -850,10 +1126,10 @@ public void onFailure(String source, Exception e) {
                 });
 
                 processedFirstTask.await();
-                masterService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
+                        timeDiffInMillis += ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
                             Settings.EMPTY
                         ).millis() + randomLongBetween(1, 1000000);
                         throw new IllegalArgumentException("Testing handling of exceptions in the cluster state task");
@@ -869,10 +1145,10 @@ public void onFailure(String source, Exception e) {
                         latch.countDown();
                     }
                 });
-                masterService.submitStateUpdateTask("test3", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test3", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
+                        timeDiffInMillis += ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
                             Settings.EMPTY
                         ).millis() + randomLongBetween(1, 1000000);
                         return ClusterState.builder(currentState).incrementVersion().build();
@@ -888,10 +1164,10 @@ public void onFailure(String source, Exception e) {
                         fail();
                     }
                 });
-                masterService.submitStateUpdateTask("test4", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test4", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
-                        relativeTimeInMillis += MasterService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
+                        timeDiffInMillis += ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(
                             Settings.EMPTY
                         ).millis() + randomLongBetween(1, 1000000);
                         return currentState;
@@ -907,7 +1183,7 @@ public void onFailure(String source, Exception e) {
                         fail();
                     }
                 });
-                masterService.submitStateUpdateTask("test5", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test5", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return ClusterState.builder(currentState).incrementVersion().build();
@@ -923,7 +1199,7 @@ public void onFailure(String source, Exception e) {
                         fail();
                     }
                 });
-                masterService.submitStateUpdateTask("test6", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test6", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return ClusterState.builder(currentState).incrementVersion().build();
@@ -941,7 +1217,7 @@ public void onFailure(String source, Exception e) {
                 });
                 // Additional update task to make sure all previous logging made it to the loggerName
                 // We don't check logging for this on since there is no guarantee that it will occur before our check
-                masterService.submitStateUpdateTask("test7", new ClusterStateUpdateTask() {
+                clusterManagerService.submitStateUpdateTask("test7", new ClusterStateUpdateTask() {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return currentState;
@@ -968,7 +1244,7 @@ public void testAcking() throws InterruptedException {
         final DiscoveryNode node2 = new DiscoveryNode("node2", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         final DiscoveryNode node3 = new DiscoveryNode("node3", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         try (
-            MasterService masterService = new MasterService(
+            ClusterManagerService clusterManagerService = new ClusterManagerService(
                 Settings.builder()
                     .put(ClusterName.CLUSTER_NAME_SETTING.getKey(), MasterServiceTests.class.getSimpleName())
                     .put(Node.NODE_NAME_SETTING.getKey(), "test_node")
@@ -983,9 +1259,9 @@ public void testAcking() throws InterruptedException {
                 .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
                 .build();
             final AtomicReference<ClusterStatePublisher> publisherRef = new AtomicReference<>();
-            masterService.setClusterStatePublisher((e, pl, al) -> publisherRef.get().publish(e, pl, al));
-            masterService.setClusterStateSupplier(() -> initialClusterState);
-            masterService.start();
+            clusterManagerService.setClusterStatePublisher((e, pl, al) -> publisherRef.get().publish(e, pl, al));
+            clusterManagerService.setClusterStateSupplier(() -> initialClusterState);
+            clusterManagerService.start();
 
             // check that we don't time out before even committing the cluster state
             {
@@ -997,7 +1273,7 @@ public void testAcking() throws InterruptedException {
                     )
                 );
 
-                masterService.submitStateUpdateTask("test2", new AckedClusterStateUpdateTask<Void>(null, null) {
+                clusterManagerService.submitStateUpdateTask("test2", new AckedClusterStateUpdateTask<Void>(null, null) {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return ClusterState.builder(currentState).build();
@@ -1052,7 +1328,7 @@ public void onAckTimeout() {
                     ackListener.onNodeAck(node3, null);
                 });
 
-                masterService.submitStateUpdateTask("test2", new AckedClusterStateUpdateTask<Void>(null, null) {
+                clusterManagerService.submitStateUpdateTask("test2", new AckedClusterStateUpdateTask<Void>(null, null) {
                     @Override
                     public ClusterState execute(ClusterState currentState) {
                         return ClusterState.builder(currentState).build();
@@ -1095,11 +1371,93 @@ public void onAckTimeout() {
         }
     }
 
+    public void testDeprecatedMasterServiceUpdateTaskThreadName() {
+        Thread.currentThread().setName(MasterService.MASTER_UPDATE_THREAD_NAME);
+        assertThat(MasterService.assertClusterManagerUpdateThread(), is(Boolean.TRUE));
+        assertThrows(AssertionError.class, () -> MasterService.assertNotClusterManagerUpdateThread("test"));
+        Thread.currentThread().setName(MasterService.CLUSTER_MANAGER_UPDATE_THREAD_NAME);
+        assertThat(MasterService.assertClusterManagerUpdateThread(), is(Boolean.TRUE));
+        assertThrows(AssertionError.class, () -> MasterService.assertNotClusterManagerUpdateThread("test"));
+        Thread.currentThread().setName("test not cluster manager update thread");
+        assertThat(MasterService.assertNotClusterManagerUpdateThread("test"), is(Boolean.TRUE));
+        assertThrows(AssertionError.class, () -> MasterService.assertClusterManagerUpdateThread());
+    }
+
+    @Timeout(millis = 5_000)
+    public void testTaskTimeout() throws InterruptedException {
+        try (ClusterManagerService clusterManagerService = createClusterManagerService(true)) {
+            final AtomicInteger failureCount = new AtomicInteger();
+            final AtomicInteger successCount = new AtomicInteger();
+            final CountDownLatch taskStartLatch = new CountDownLatch(1);
+            final CountDownLatch blockingTaskLatch = new CountDownLatch(1);
+            final CountDownLatch timeoutLatch = new CountDownLatch(1);
+            final ClusterStateTaskListener blockingListener = new ClusterStateTaskListener() {
+                @Override
+                public void onFailure(String source, Exception e) {
+                    fail("Unexpected failure");
+                }
+
+                @Override
+                public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                    successCount.incrementAndGet();
+                    taskStartLatch.countDown();
+                    try {
+                        blockingTaskLatch.await();
+                    } catch (InterruptedException e) {
+                        fail("Interrupted");
+                    }
+                }
+            };
+            final ClusterStateTaskListener timeoutListener = new ClusterStateTaskListener() {
+                @Override
+                public void onFailure(String source, Exception e) {
+                    assertEquals("timeout", source);
+                    failureCount.incrementAndGet();
+                    timeoutLatch.countDown();
+                }
+
+                @Override
+                public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                    fail("Unexpected success");
+                }
+            };
+
+            final ClusterStateTaskExecutor<Object> executor = (currentState, tasks) -> ClusterStateTaskExecutor.ClusterTasksResult.builder()
+                .successes(tasks)
+                .build(currentState);
+
+            // start a task and wait for it to start and block on the clusterStateProcessed callback
+            clusterManagerService.submitStateUpdateTask(
+                "success",
+                new Object(),
+                ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                executor,
+                blockingListener
+            );
+            taskStartLatch.await();
+
+            // start a second task that is guaranteed to timeout as the first task is still running
+            clusterManagerService.submitStateUpdateTask(
+                "timeout",
+                new Object(),
+                ClusterStateTaskConfig.build(randomFrom(Priority.values()), TimeValue.timeValueMillis(1L)),
+                executor,
+                timeoutListener
+            );
+
+            // wait for the timeout to happen, then unblock and assert one success and one failure
+            timeoutLatch.await();
+            blockingTaskLatch.countDown();
+            assertEquals(1, failureCount.get());
+            assertEquals(1, successCount.get());
+        }
+    }
+
     /**
-     * Returns the cluster state that the master service uses (and that is provided by the discovery layer)
+     * Returns the cluster state that the cluster-manager service uses (and that is provided by the discovery layer)
      */
-    public static ClusterState discoveryState(MasterService masterService) {
-        return masterService.state();
+    public static ClusterState discoveryState(ClusterManagerService clusterManagerService) {
+        return clusterManagerService.state();
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/cluster/service/TaskBatcherTests.java b/server/src/test/java/org/opensearch/cluster/service/TaskBatcherTests.java
index aec2641b355d3..070fde523fe87 100644
--- a/server/src/test/java/org/opensearch/cluster/service/TaskBatcherTests.java
+++ b/server/src/test/java/org/opensearch/cluster/service/TaskBatcherTests.java
@@ -71,10 +71,10 @@ public void setUpBatchingTaskExecutor() throws Exception {
         taskBatcher = new TestTaskBatcher(logger, threadExecutor);
     }
 
-    class TestTaskBatcher extends TaskBatcher {
+    static class TestTaskBatcher extends TaskBatcher {
 
         TestTaskBatcher(Logger logger, PrioritizedOpenSearchThreadPoolExecutor threadExecutor) {
-            super(logger, threadExecutor);
+            super(logger, threadExecutor, getMockListener());
         }
 
         @Override
@@ -279,6 +279,87 @@ public void processed(String source) {
         }
     }
 
+    public void testNoTasksAreDroppedInParallelSubmission() throws BrokenBarrierException, InterruptedException {
+        int numberOfThreads = randomIntBetween(2, 8);
+        TaskExecutor[] executors = new TaskExecutor[numberOfThreads];
+        for (int i = 0; i < numberOfThreads; i++) {
+            executors[i] = new TaskExecutor();
+        }
+
+        int tasksSubmittedPerThread = randomIntBetween(2, 1024);
+
+        CopyOnWriteArrayList<Tuple<String, Throwable>> failures = new CopyOnWriteArrayList<>();
+        CountDownLatch updateLatch = new CountDownLatch(numberOfThreads * tasksSubmittedPerThread);
+
+        final TestListener listener = new TestListener() {
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error(() -> new ParameterizedMessage("unexpected failure: [{}]", source), e);
+                failures.add(new Tuple<>(source, e));
+                updateLatch.countDown();
+            }
+
+            @Override
+            public void processed(String source) {
+                updateLatch.countDown();
+            }
+        };
+
+        CyclicBarrier barrier = new CyclicBarrier(1 + numberOfThreads);
+
+        for (int i = 0; i < numberOfThreads; i++) {
+            final int index = i;
+            Thread thread = new Thread(() -> {
+                try {
+                    barrier.await();
+                    CyclicBarrier tasksBarrier = new CyclicBarrier(1 + tasksSubmittedPerThread);
+                    for (int j = 0; j < tasksSubmittedPerThread; j++) {
+                        int taskNumber = j;
+                        Thread taskThread = new Thread(() -> {
+                            try {
+                                tasksBarrier.await();
+                                submitTask(
+                                    "[" + index + "][" + taskNumber + "]",
+                                    taskNumber,
+                                    ClusterStateTaskConfig.build(randomFrom(Priority.values())),
+                                    executors[index],
+                                    listener
+                                );
+                                tasksBarrier.await();
+                            } catch (InterruptedException | BrokenBarrierException e) {
+                                throw new AssertionError(e);
+                            }
+                        });
+                        // submit tasks per batchingKey in parallel
+                        taskThread.start();
+                    }
+                    // wait for all task threads to be ready
+                    tasksBarrier.await();
+                    // wait for all task threads to finish
+                    tasksBarrier.await();
+                    barrier.await();
+                } catch (InterruptedException | BrokenBarrierException e) {
+                    throw new AssertionError(e);
+                }
+            });
+            thread.start();
+        }
+
+        // wait for all executor threads to be ready
+        barrier.await();
+        // wait for all executor threads to finish
+        barrier.await();
+
+        updateLatch.await();
+
+        assertThat(failures, empty());
+
+        for (int i = 0; i < numberOfThreads; i++) {
+            // assert that total executed tasks is same for every executor as we initiated
+            assertEquals(tasksSubmittedPerThread, executors[i].tasks.size());
+        }
+    }
+
     public void testSingleBatchSubmission() throws InterruptedException {
         Map<Integer, TestListener> tasks = new HashMap<>();
         final int numOfTasks = randomInt(10);
@@ -316,7 +397,7 @@ public void testDuplicateSubmission() throws InterruptedException {
             submitTask("blocking", blockingTask);
 
             TestExecutor<SimpleTask> executor = tasks -> {};
-            SimpleTask task = new SimpleTask(1);
+            SimpleTask task1 = new SimpleTask(1);
             TestListener listener = new TestListener() {
                 @Override
                 public void processed(String source) {
@@ -329,21 +410,134 @@ public void onFailure(String source, Exception e) {
                 }
             };
 
-            submitTask("first time", task, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+            submitTask("first time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
 
+            // submitting same task1 again, it should throw exception.
             final IllegalStateException e = expectThrows(
                 IllegalStateException.class,
-                () -> submitTask("second time", task, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener)
+                () -> submitTask("second time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener)
             );
             assertThat(e, hasToString(containsString("task [1] with source [second time] is already queued")));
 
-            submitTask("third time a charm", new SimpleTask(1), ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+            // inserting new task with same data, this should pass as it is new object and reference is different.
+            SimpleTask task2 = new SimpleTask(1);
+            // equals method returns true for both task
+            assertTrue(task1.equals(task2));
+            // references of both tasks are different.
+            assertFalse(task1 == task2);
+            // submitting this task should be allowed, as it is new object.
+            submitTask("third time a charm", task2, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+
+            // submitting same task2 again, it should throw exception, since it was submitted last time
+            final IllegalStateException e2 = expectThrows(
+                IllegalStateException.class,
+                () -> submitTask("second time", task2, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener)
+            );
+            assertThat(e2, hasToString(containsString("task [1] with source [second time] is already queued")));
+
+            assertThat(latch.getCount(), equalTo(2L));
+        }
+        latch.await();
+    }
+
+    public void testDuplicateSubmissionAfterTimeout() throws InterruptedException {
+        final CountDownLatch latch = new CountDownLatch(2);
+        final CountDownLatch timeOutLatch = new CountDownLatch(1);
+        try (BlockingTask blockingTask = new BlockingTask(Priority.IMMEDIATE)) {
+            submitTask("blocking", blockingTask);
+
+            TestExecutor<SimpleTask> executor = tasks -> {};
+            SimpleTask task1 = new SimpleTask(1);
+            TestListener listener = new TestListener() {
+                @Override
+                public void processed(String source) {
+                    latch.countDown();
+                }
 
+                @Override
+                public void onFailure(String source, Exception e) {
+                    if (e instanceof ProcessClusterEventTimeoutException) {
+                        timeOutLatch.countDown();
+                    } else {
+                        throw new AssertionError(e);
+                    }
+                }
+            };
+
+            submitTask("first time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+            ArrayList<TaskBatcher.BatchedTask> tasks = new ArrayList();
+            tasks.add(
+                taskBatcher.new UpdateTask(
+                    ClusterStateTaskConfig.build(Priority.NORMAL).priority(), "first time", task1, listener, executor
+                )
+            );
+
+            // task1 got timed out, it will be removed from map.
+            taskBatcher.onTimeoutInternal(tasks, TimeValue.ZERO);
+            timeOutLatch.await(); // wait for task to get timeout
+            // submitting same task1 again, it should get submitted, since last task was timeout.
+            submitTask("first time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
             assertThat(latch.getCount(), equalTo(2L));
         }
         latch.await();
     }
 
+    public void testDuplicateSubmissionAfterExecution() throws InterruptedException {
+        final CountDownLatch firstTaskLatch = new CountDownLatch(1);
+        final CountDownLatch latch = new CountDownLatch(2);
+
+        TestExecutor<SimpleTask> executor = tasks -> {};
+        SimpleTask task1 = new SimpleTask(1);
+        TestListener listener = new TestListener() {
+            @Override
+            public void processed(String source) {
+                firstTaskLatch.countDown();
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                if (e instanceof ProcessClusterEventTimeoutException) {
+                    latch.countDown();
+                } else {
+                    throw new AssertionError(e);
+                }
+            }
+        };
+        submitTask("first time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+
+        firstTaskLatch.await(); // wait till task is not executed
+
+        // submitting same task1 again, it should get submitted, since last task was executed.
+        submitTask("first time", task1, ClusterStateTaskConfig.build(Priority.NORMAL), executor, listener);
+
+        latch.await(); // wait till all tasks are not completed.
+    }
+
+    protected static TaskBatcherListener getMockListener() {
+        return new TaskBatcherListener() {
+            @Override
+            public void onBeginSubmit(List<? extends TaskBatcher.BatchedTask> tasks) {
+                // No Op
+            }
+
+            @Override
+            public void onSubmitFailure(List<? extends TaskBatcher.BatchedTask> tasks) {
+                // No Op
+            }
+
+            @Override
+            public void onBeginProcessing(List<? extends TaskBatcher.BatchedTask> tasks) {
+                // No Op
+            }
+
+            @Override
+            public void onTimeout(List<? extends TaskBatcher.BatchedTask> tasks) {
+                // No Op
+            }
+        };
+    }
+
     private static class SimpleTask {
         private final int id;
 
@@ -353,12 +547,16 @@ private SimpleTask(int id) {
 
         @Override
         public int hashCode() {
-            return super.hashCode();
+            return this.id;
         }
 
         @Override
         public boolean equals(Object obj) {
-            return super.equals(obj);
+            return ((SimpleTask) obj).getId() == this.id;
+        }
+
+        public int getId() {
+            return id;
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/cluster/structure/RoutingIteratorTests.java b/server/src/test/java/org/opensearch/cluster/structure/RoutingIteratorTests.java
index 68ad47fa1bbc9..86adfc1279d9a 100644
--- a/server/src/test/java/org/opensearch/cluster/structure/RoutingIteratorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/structure/RoutingIteratorTests.java
@@ -38,8 +38,10 @@
 import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.GroupShardsIterator;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.cluster.routing.PlainShardIterator;
 import org.opensearch.cluster.routing.RotationShardShuffler;
@@ -48,20 +50,28 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardShuffler;
 import org.opensearch.cluster.routing.ShardsIterator;
+import org.opensearch.cluster.routing.WeightedRouting;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
+import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexModule;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.threadpool.TestThreadPool;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 
 import static java.util.Collections.singletonMap;
 import static java.util.Collections.unmodifiableMap;
+import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
@@ -470,7 +480,10 @@ public void testShardsAndPreferNodeRouting() {
         }
     }
 
-    public void testReplicaShardPreferenceIters() throws Exception {
+    public void testReplicaShardPreferenceIters() {
+        AllocationService strategy = createAllocationService(
+            Settings.builder().put("cluster.routing.allocation.node_concurrent_recoveries", 10).build()
+        );
         OperationRouting operationRouting = new OperationRouting(
             Settings.EMPTY,
             new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
@@ -482,19 +495,565 @@ public void testReplicaShardPreferenceIters() throws Exception {
 
         RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
 
-        final ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
             .metadata(metadata)
             .routingTable(routingTable)
+            .build();
+
+        clusterState = ClusterState.builder(clusterState)
             .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")).add(newNode("node3")).localNodeId("node1"))
             .build();
+        clusterState = strategy.reroute(clusterState, "reroute");
+        clusterState = strategy.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+
+        clusterState = strategy.reroute(clusterState, "reroute"); // Move replicas to initializing
+
+        // When replicas haven't initialized, it comes back with the primary first, then initializing replicas
+        GroupShardsIterator<ShardIterator> shardIterators = operationRouting.searchShards(
+            clusterState,
+            new String[] { "test" },
+            null,
+            "_replica_first"
+        );
+        assertThat(shardIterators.size(), equalTo(2)); // two potential shards
+        ShardIterator iter = shardIterators.iterator().next();
+        assertThat(iter.size(), equalTo(3)); // three potential candidates for the shard
+        ShardRouting routing = iter.nextOrNull();
+        assertNotNull(routing);
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertTrue(routing.primary()); // replicas haven't initialized yet, so primary is first
+        assertTrue(routing.started());
+        routing = iter.nextOrNull();
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+        assertTrue(routing.initializing());
+        routing = iter.nextOrNull();
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+        assertTrue(routing.initializing());
+        clusterState = strategy.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+
+        clusterState = strategy.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+
+        shardIterators = operationRouting.searchShards(clusterState, new String[] { "test" }, null, "_replica");
+        assertThat(shardIterators.size(), equalTo(2)); // two potential shards
+        iter = shardIterators.iterator().next();
+        assertThat(iter.size(), equalTo(2)); // two potential replicas for the shard
+        routing = iter.nextOrNull();
+        assertNotNull(routing);
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+        routing = iter.nextOrNull();
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+
+        shardIterators = operationRouting.searchShards(clusterState, new String[] { "test" }, null, "_replica_first");
+        assertThat(shardIterators.size(), equalTo(2)); // two potential shards
+        iter = shardIterators.iterator().next();
+        assertThat(iter.size(), equalTo(3)); // three potential candidates for the shard
+        routing = iter.nextOrNull();
+        assertNotNull(routing);
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+        routing = iter.nextOrNull();
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertFalse(routing.primary());
+        // finally the primary
+        routing = iter.nextOrNull();
+        assertThat(routing.shardId().id(), anyOf(equalTo(0), equalTo(1)));
+        assertTrue(routing.primary());
+    }
+
+    public void testSearchableSnapshotPreference() {
+        AllocationService strategy = createAllocationService(
+            Settings.builder().put("cluster.routing.allocation.node_concurrent_recoveries", 10).build()
+        );
+        OperationRouting operationRouting = new OperationRouting(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        // Modify the index to be a searchable snapshot index
+        Metadata metadata = Metadata.builder()
+            .put(
+                IndexMetadata.builder("test")
+                    .settings(
+                        Settings.builder()
+                            .put(settings(Version.CURRENT).build())
+                            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                    )
+                    .numberOfShards(2)
+                    .numberOfReplicas(2)
+            )
+            .build();
+
+        RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable)
+            .build();
+
+        clusterState = ClusterState.builder(clusterState)
+            .nodes(
+                DiscoveryNodes.builder()
+                    .add(newNode("node1", Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)))
+                    .add(newNode("node2", Collections.singleton(DiscoveryNodeRole.SEARCH_ROLE)))
+                    .add(newNode("node3", Collections.singleton(DiscoveryNodeRole.SEARCH_ROLE)))
+                    .localNodeId("node1")
+            )
+            .build();
+
+        clusterState = strategy.reroute(clusterState, "reroute"); // Move primaries to initializing
+        clusterState = strategy.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+
+        clusterState = strategy.reroute(clusterState, "reroute"); // Move replicas to initializing
+        clusterState = strategy.applyStartedShards(clusterState, clusterState.getRoutingNodes().shardsWithState(INITIALIZING));
+
+        // When replicas haven't initialized, it comes back with the primary first, then initializing replicas
+        GroupShardsIterator<ShardIterator> shardIterators = operationRouting.searchShards(
+            clusterState,
+            new String[] { "test" },
+            null,
+            null
+        );
+        assertThat(shardIterators.size(), equalTo(2)); // two potential shards
+        ShardIterator iter = shardIterators.iterator().next();
+        assertThat(iter.size(), equalTo(1)); // one potential candidate (primary) for the shard
+
+        ShardRouting routing = iter.nextOrNull();
+        assertNotNull(routing);
+        assertTrue(routing.primary()); // Default preference is primary
+        assertTrue(routing.started());
+        routing = iter.nextOrNull();
+        assertNull(routing); // No other candidate apart from primary
+    }
 
-        String[] removedPreferences = { "_primary", "_primary_first", "_replica", "_replica_first" };
-        for (String pref : removedPreferences) {
-            expectThrows(
-                IllegalArgumentException.class,
-                () -> operationRouting.searchShards(clusterState, new String[] { "test" }, null, pref)
+    public void testWeightedRoutingWithDifferentWeights() {
+        TestThreadPool threadPool = null;
+        try {
+            Settings.Builder settings = Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.routing.allocation.awareness.attributes", "zone");
+            AllocationService strategy = createAllocationService(settings.build());
+
+            Metadata metadata = Metadata.builder()
+                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+                .build();
+
+            RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+            ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            ClusterService clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            Map<String, String> node1Attributes = new HashMap<>();
+            node1Attributes.put("zone", "zone1");
+            Map<String, String> node2Attributes = new HashMap<>();
+            node2Attributes.put("zone", "zone2");
+            Map<String, String> node3Attributes = new HashMap<>();
+            node3Attributes.put("zone", "zone3");
+            clusterState = ClusterState.builder(clusterState)
+                .nodes(
+                    DiscoveryNodes.builder()
+                        .add(newNode("node1", unmodifiableMap(node1Attributes)))
+                        .add(newNode("node2", unmodifiableMap(node2Attributes)))
+                        .add(newNode("node3", unmodifiableMap(node3Attributes)))
+                        .localNodeId("node1")
+                )
+                .build();
+            clusterState = strategy.reroute(clusterState, "reroute");
+
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+            Map<String, Double> weights = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+            ShardIterator shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+
+            assertEquals(2, shardIterator.size());
+            ShardRouting shardRouting;
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node3").contains(shardRouting.currentNodeId()));
+
+            weights = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 1.0);
+            weightedRouting = new WeightedRouting("zone", weights);
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(3, shardIterator.size());
+
+            weights = Map.of("zone1", -1.0, "zone2", 0.0, "zone3", 1.0);
+            weightedRouting = new WeightedRouting("zone", weights);
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(1, shardIterator.size());
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node2", "node1").contains(shardRouting.currentNodeId()));
+
+            weights = Map.of("zone1", 3.0, "zone2", 2.0, "zone3", 0.0);
+            weightedRouting = new WeightedRouting("zone", weights);
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, null);
+            assertEquals(3, shardIterator.size());
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+        } finally {
+            terminate(threadPool);
+        }
+    }
+
+    public void testWeightedRoutingInMemoryStore() {
+        TestThreadPool threadPool = null;
+        try {
+            Settings.Builder settings = Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.routing.allocation.awareness.attributes", "zone");
+            AllocationService strategy = createAllocationService(settings.build());
+
+            Metadata metadata = Metadata.builder()
+                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+                .build();
+
+            RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+            ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            ClusterService clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            Map<String, String> node1Attributes = new HashMap<>();
+            node1Attributes.put("zone", "zone1");
+            Map<String, String> node2Attributes = new HashMap<>();
+            node2Attributes.put("zone", "zone2");
+            Map<String, String> node3Attributes = new HashMap<>();
+            node3Attributes.put("zone", "zone3");
+            clusterState = ClusterState.builder(clusterState)
+                .nodes(
+                    DiscoveryNodes.builder()
+                        .add(newNode("node1", unmodifiableMap(node1Attributes)))
+                        .add(newNode("node2", unmodifiableMap(node2Attributes)))
+                        .add(newNode("node3", unmodifiableMap(node3Attributes)))
+                        .localNodeId("node1")
+                )
+                .build();
+            clusterState = strategy.reroute(clusterState, "reroute");
+
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+            Map<String, Double> weights = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+            IndexShardRoutingTable indexShardRoutingTable = clusterState.routingTable().index("test").shard(0);
+
+            assertNull(
+                indexShardRoutingTable.getActiveShardsByWeight().get(new IndexShardRoutingTable.WeightedRoutingKey(weightedRouting))
+            );
+            ShardIterator shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(2, shardIterator.size());
+            ShardRouting shardRouting;
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node3").contains(shardRouting.currentNodeId()));
+
+            // Make iterator call with same WeightedRouting instance
+            assertNotNull(
+                indexShardRoutingTable.getActiveShardsByWeight().get(new IndexShardRoutingTable.WeightedRoutingKey(weightedRouting))
+            );
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(2, shardIterator.size());
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node3").contains(shardRouting.currentNodeId()));
+
+            // Make iterator call with new instance of WeightedRouting but same weights
+            Map<String, Double> weights1 = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            weightedRouting = new WeightedRouting("zone", weights1);
+            assertNotNull(
+                indexShardRoutingTable.getActiveShardsByWeight().get(new IndexShardRoutingTable.WeightedRoutingKey(weightedRouting))
+            );
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(2, shardIterator.size());
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node3").contains(shardRouting.currentNodeId()));
+
+            // Make iterator call with different weights
+            Map<String, Double> weights2 = Map.of("zone1", 1.0, "zone2", 0.0, "zone3", 1.0);
+            weightedRouting = new WeightedRouting("zone", weights2);
+            assertNull(
+                indexShardRoutingTable.getActiveShardsByWeight().get(new IndexShardRoutingTable.WeightedRoutingKey(weightedRouting))
             );
+            shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, false, null);
+            assertEquals(2, shardIterator.size());
+            shardRouting = shardIterator.nextOrNull();
+            assertNotNull(shardRouting);
+            assertFalse(Arrays.asList("node2").contains(shardRouting.currentNodeId()));
+
+        } finally {
+            terminate(threadPool);
         }
     }
 
+    /**
+     * Test to validate that shard routing state is maintained across requests
+     */
+    public void testWeightedRoutingShardState() {
+        TestThreadPool threadPool = null;
+        try {
+            Settings.Builder settings = Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.routing.allocation.awareness.attributes", "zone");
+            AllocationService strategy = createAllocationService(settings.build());
+
+            Metadata metadata = Metadata.builder()
+                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+                .build();
+
+            RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+            ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            ClusterService clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            Map<String, String> node1Attributes = new HashMap<>();
+            node1Attributes.put("zone", "zone1");
+            Map<String, String> node2Attributes = new HashMap<>();
+            node2Attributes.put("zone", "zone2");
+            Map<String, String> node3Attributes = new HashMap<>();
+            node3Attributes.put("zone", "zone3");
+            clusterState = ClusterState.builder(clusterState)
+                .nodes(
+                    DiscoveryNodes.builder()
+                        .add(newNode("node1", unmodifiableMap(node1Attributes)))
+                        .add(newNode("node2", unmodifiableMap(node2Attributes)))
+                        .add(newNode("node3", unmodifiableMap(node3Attributes)))
+                        .localNodeId("node1")
+                )
+                .build();
+            clusterState = strategy.reroute(clusterState, "reroute");
+
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+
+            Map<String, Double> weights = Map.of("zone1", 3.0, "zone2", 2.0, "zone3", 0.0);
+            WeightedRouting weightedRouting = new WeightedRouting("zone", weights);
+
+            Map<String, Integer> requestCount = new HashMap<>();
+
+            for (int i = 0; i < 5; i++) {
+                ShardIterator shardIterator = clusterState.routingTable()
+                    .index("test")
+                    .shard(0)
+                    .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, null);
+
+                assertEquals(3, shardIterator.size());
+                ShardRouting shardRouting;
+                shardRouting = shardIterator.nextOrNull();
+                assertNotNull(shardRouting);
+                requestCount.put(shardRouting.currentNodeId(), requestCount.getOrDefault(shardRouting.currentNodeId(), 0) + 1);
+            }
+            assertEquals(3, requestCount.get("node1").intValue());
+            assertEquals(2, requestCount.get("node2").intValue());
+
+        } finally {
+            terminate(threadPool);
+        }
+    }
+
+    /**
+     * Test to validate that shard routing state is maintained across requests, requests are assigned to nodes
+     * according to assigned routing weights
+     */
+    public void testWeightedRoutingShardStateWithDifferentWeights() {
+        TestThreadPool threadPool = null;
+        try {
+            Settings.Builder settings = Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.routing.allocation.awareness.attributes", "zone");
+            AllocationService strategy = createAllocationService(settings.build());
+
+            Metadata metadata = Metadata.builder()
+                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+                .build();
+
+            RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+            ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build();
+
+            threadPool = new TestThreadPool("testThatOnlyNodesSupport");
+            ClusterService clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            Map<String, String> node1Attributes = new HashMap<>();
+            node1Attributes.put("zone", "zone1");
+            Map<String, String> node2Attributes = new HashMap<>();
+            node2Attributes.put("zone", "zone2");
+            Map<String, String> node3Attributes = new HashMap<>();
+            node3Attributes.put("zone", "zone3");
+            clusterState = ClusterState.builder(clusterState)
+                .nodes(
+                    DiscoveryNodes.builder()
+                        .add(newNode("node1", unmodifiableMap(node1Attributes)))
+                        .add(newNode("node2", unmodifiableMap(node2Attributes)))
+                        .add(newNode("node3", unmodifiableMap(node3Attributes)))
+                        .localNodeId("node1")
+                )
+                .build();
+            clusterState = strategy.reroute(clusterState, "reroute");
+
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            List<Map<String, Double>> weightsList = new ArrayList<>();
+            Map<String, Double> weights1 = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            weightsList.add(weights1);
+
+            Map<String, Double> weights2 = Map.of("zone1", 1.0, "zone2", 0.0, "zone3", 1.0);
+            weightsList.add(weights2);
+
+            Map<String, Double> weights3 = Map.of("zone1", 0.0, "zone2", 1.0, "zone3", 1.0);
+            weightsList.add(weights3);
+
+            Map<String, Double> weights4 = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            weightsList.add(weights4);
+
+            for (int i = 0; i < weightsList.size(); i++) {
+                WeightedRouting weightedRouting = new WeightedRouting("zone", weightsList.get(i));
+                ShardIterator shardIterator = clusterState.routingTable()
+                    .index("test")
+                    .shard(0)
+                    .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, null);
+
+                ShardRouting shardRouting1 = shardIterator.nextOrNull();
+
+                shardIterator = clusterState.routingTable()
+                    .index("test")
+                    .shard(0)
+                    .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, null);
+
+                ShardRouting shardRouting2 = shardIterator.nextOrNull();
+
+                shardIterator = clusterState.routingTable()
+                    .index("test")
+                    .shard(0)
+                    .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, null);
+
+                ShardRouting shardRouting3 = shardIterator.nextOrNull();
+
+                assertEquals(shardRouting1.currentNodeId(), shardRouting3.currentNodeId());
+                assertNotEquals(shardRouting1.currentNodeId(), shardRouting2.currentNodeId());
+            }
+
+        } finally {
+            terminate(threadPool);
+        }
+    }
+
+    /**
+     * Test to validate that simple weighted shard routing with seed return same shard routing on each call
+     */
+    public void testActiveInitializingShardsWeightedItWithCustomSeed() {
+        TestThreadPool threadPool = new TestThreadPool("testActiveInitializingShardsWeightedItWithCustomSeed");
+        try {
+            Settings.Builder settings = Settings.builder()
+                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
+                .put("cluster.routing.allocation.awareness.attributes", "zone");
+            AllocationService strategy = createAllocationService(settings.build());
+
+            Metadata metadata = Metadata.builder()
+                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(2))
+                .build();
+
+            RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
+
+            ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+                .metadata(metadata)
+                .routingTable(routingTable)
+                .build();
+
+            ClusterService clusterService = ClusterServiceUtils.createClusterService(threadPool);
+
+            Map<String, String> node1Attributes = new HashMap<>();
+            node1Attributes.put("zone", "zone1");
+            Map<String, String> node2Attributes = new HashMap<>();
+            node2Attributes.put("zone", "zone2");
+            Map<String, String> node3Attributes = new HashMap<>();
+            node3Attributes.put("zone", "zone3");
+            clusterState = ClusterState.builder(clusterState)
+                .nodes(
+                    DiscoveryNodes.builder()
+                        .add(newNode("node1", unmodifiableMap(node1Attributes)))
+                        .add(newNode("node2", unmodifiableMap(node2Attributes)))
+                        .add(newNode("node3", unmodifiableMap(node3Attributes)))
+                        .localNodeId("node1")
+                )
+                .build();
+            clusterState = strategy.reroute(clusterState, "reroute");
+
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
+            List<Map<String, Double>> weightsList = new ArrayList<>();
+            Map<String, Double> weights1 = Map.of("zone1", 1.0, "zone2", 1.0, "zone3", 0.0);
+            weightsList.add(weights1);
+
+            WeightedRouting weightedRouting = new WeightedRouting("zone", weights1);
+            ShardIterator shardIterator = clusterState.routingTable()
+                .index("test")
+                .shard(0)
+                .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, 1);
+
+            ShardRouting shardRouting1 = shardIterator.nextOrNull();
+
+            for (int i = 0; i < 50; i++) {
+                shardIterator = clusterState.routingTable()
+                    .index("test")
+                    .shard(0)
+                    .activeInitializingShardsWeightedIt(weightedRouting, clusterState.nodes(), 1, true, 1);
+
+                ShardRouting shardRouting2 = shardIterator.nextOrNull();
+
+                assertEquals(shardRouting1.currentNodeId(), shardRouting2.currentNodeId());
+            }
+
+        } finally {
+            terminate(threadPool);
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/common/ChannelsTests.java b/server/src/test/java/org/opensearch/common/ChannelsTests.java
index d6bf48b573722..23d3784b89d66 100644
--- a/server/src/test/java/org/opensearch/common/ChannelsTests.java
+++ b/server/src/test/java/org/opensearch/common/ChannelsTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.common;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.Channels;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 import org.junit.After;
diff --git a/server/src/test/java/org/opensearch/common/FieldMemoryStatsTests.java b/server/src/test/java/org/opensearch/common/FieldMemoryStatsTests.java
index 610ad32f0ce35..e2c155dd47d80 100644
--- a/server/src/test/java/org/opensearch/common/FieldMemoryStatsTests.java
+++ b/server/src/test/java/org/opensearch/common/FieldMemoryStatsTests.java
@@ -31,12 +31,13 @@
 
 package org.opensearch.common;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
 
 public class FieldMemoryStatsTests extends OpenSearchTestCase {
 
@@ -54,21 +55,21 @@ public void testHashCodeEquals() {
         FieldMemoryStats stats = randomFieldMemoryStats();
         assertEquals(stats, stats);
         assertEquals(stats.hashCode(), stats.hashCode());
-        ObjectLongHashMap<String> map1 = new ObjectLongHashMap<>();
-        map1.put("bar", 1);
+        final Map<String, Long> map1 = new HashMap<>();
+        map1.put("bar", 1L);
         FieldMemoryStats stats1 = new FieldMemoryStats(map1);
-        ObjectLongHashMap<String> map2 = new ObjectLongHashMap<>();
-        map2.put("foo", 2);
+        final Map<String, Long> map2 = new HashMap<>();
+        map2.put("foo", 2L);
         FieldMemoryStats stats2 = new FieldMemoryStats(map2);
 
-        ObjectLongHashMap<String> map3 = new ObjectLongHashMap<>();
-        map3.put("foo", 2);
-        map3.put("bar", 1);
+        final Map<String, Long> map3 = new HashMap<>();
+        map3.put("foo", 2L);
+        map3.put("bar", 1L);
         FieldMemoryStats stats3 = new FieldMemoryStats(map3);
 
-        ObjectLongHashMap<String> map4 = new ObjectLongHashMap<>();
-        map4.put("foo", 2);
-        map4.put("bar", 1);
+        final Map<String, Long> map4 = new HashMap<>();
+        map4.put("foo", 2L);
+        map4.put("bar", 1L);
         FieldMemoryStats stats4 = new FieldMemoryStats(map4);
 
         assertNotEquals(stats1, stats2);
@@ -83,21 +84,21 @@ public void testHashCodeEquals() {
     }
 
     public void testAdd() {
-        ObjectLongHashMap<String> map1 = new ObjectLongHashMap<>();
-        map1.put("bar", 1);
+        final Map<String, Long> map1 = new HashMap<>();
+        map1.put("bar", 1L);
         FieldMemoryStats stats1 = new FieldMemoryStats(map1);
-        ObjectLongHashMap<String> map2 = new ObjectLongHashMap<>();
-        map2.put("foo", 2);
+        final Map<String, Long> map2 = new HashMap<>();
+        map2.put("foo", 2L);
         FieldMemoryStats stats2 = new FieldMemoryStats(map2);
 
-        ObjectLongHashMap<String> map3 = new ObjectLongHashMap<>();
-        map3.put("bar", 1);
+        final Map<String, Long> map3 = new HashMap<>();
+        map3.put("bar", 1L);
         FieldMemoryStats stats3 = new FieldMemoryStats(map3);
         stats3.add(stats1);
 
-        ObjectLongHashMap<String> map4 = new ObjectLongHashMap<>();
-        map4.put("foo", 2);
-        map4.put("bar", 2);
+        final Map<String, Long> map4 = new HashMap<>();
+        map4.put("foo", 2L);
+        map4.put("bar", 2L);
         FieldMemoryStats stats4 = new FieldMemoryStats(map4);
         assertNotEquals(stats3, stats4);
         stats3.add(stats2);
@@ -105,7 +106,7 @@ public void testAdd() {
     }
 
     public static FieldMemoryStats randomFieldMemoryStats() {
-        ObjectLongHashMap<String> map = new ObjectLongHashMap<>();
+        final Map<String, Long> map = new HashMap<>();
         int keys = randomIntBetween(1, 1000);
         for (int i = 0; i < keys; i++) {
             map.put(randomRealisticUnicodeOfCodepointLengthBetween(1, 10), randomNonNegativeLong());
diff --git a/server/src/test/java/org/opensearch/common/LocalTimeOffsetTests.java b/server/src/test/java/org/opensearch/common/LocalTimeOffsetTests.java
index 12810241e3904..b032e27397f2d 100644
--- a/server/src/test/java/org/opensearch/common/LocalTimeOffsetTests.java
+++ b/server/src/test/java/org/opensearch/common/LocalTimeOffsetTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common;
 
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.LocalTimeOffset.Gap;
 import org.opensearch.common.LocalTimeOffset.Overlap;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.lang.Runtime.Version;
 import java.time.Instant;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
@@ -278,7 +278,7 @@ public void testKnownMovesBackToPreviousDay() {
         assertKnownMovesBacktoPreviousDay("America/Moncton", "2005-10-29T03:01:00");
         assertKnownMovesBacktoPreviousDay("America/St_Johns", "2010-11-07T02:31:00");
         assertKnownMovesBacktoPreviousDay("Canada/Newfoundland", "2010-11-07T02:31:00");
-        if (JavaVersion.current().compareTo(JavaVersion.parse("11")) > 0) {
+        if (Runtime.version().compareTo(Version.parse("11")) > 0) {
             // Added in java 12
             assertKnownMovesBacktoPreviousDay("Pacific/Guam", "1969-01-25T13:01:00");
             assertKnownMovesBacktoPreviousDay("Pacific/Saipan", "1969-01-25T13:01:00");
diff --git a/server/src/test/java/org/opensearch/common/NumbersTests.java b/server/src/test/java/org/opensearch/common/NumbersTests.java
deleted file mode 100644
index 50dae2cad32c4..0000000000000
--- a/server/src/test/java/org/opensearch/common/NumbersTests.java
+++ /dev/null
@@ -1,167 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common;
-
-import com.carrotsearch.randomizedtesting.annotations.Timeout;
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.math.BigDecimal;
-import java.math.BigInteger;
-import java.util.concurrent.atomic.AtomicInteger;
-
-public class NumbersTests extends OpenSearchTestCase {
-
-    @Timeout(millis = 10000)
-    public void testToLong() {
-        assertEquals(3L, Numbers.toLong("3", false));
-        assertEquals(3L, Numbers.toLong("3.1", true));
-        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.00", false));
-        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.00", false));
-        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.00", true));
-        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.00", true));
-        assertEquals(9223372036854775807L, Numbers.toLong("9223372036854775807.99", true));
-        assertEquals(-9223372036854775808L, Numbers.toLong("-9223372036854775808.99", true));
-
-        assertEquals(
-            "Value [9223372036854775808] is out of range for a long",
-            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("9223372036854775808", false)).getMessage()
-        );
-        assertEquals(
-            "Value [-9223372036854775809] is out of range for a long",
-            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("-9223372036854775809", false)).getMessage()
-        );
-
-        assertEquals(
-            "Value [1e99999999] is out of range for a long",
-            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("1e99999999", false)).getMessage()
-        );
-        assertEquals(
-            "Value [-1e99999999] is out of range for a long",
-            expectThrows(IllegalArgumentException.class, () -> Numbers.toLong("-1e99999999", false)).getMessage()
-        );
-    }
-
-    public void testToLongExact() {
-        assertEquals(3L, Numbers.toLongExact(Long.valueOf(3L)));
-        assertEquals(3L, Numbers.toLongExact(Integer.valueOf(3)));
-        assertEquals(3L, Numbers.toLongExact(Short.valueOf((short) 3)));
-        assertEquals(3L, Numbers.toLongExact(Byte.valueOf((byte) 3)));
-        assertEquals(3L, Numbers.toLongExact(3d));
-        assertEquals(3L, Numbers.toLongExact(3f));
-        assertEquals(3L, Numbers.toLongExact(BigInteger.valueOf(3L)));
-        assertEquals(3L, Numbers.toLongExact(BigDecimal.valueOf(3L)));
-
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(3.1d));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
-        assertEquals("NaN is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
-        assertEquals("Infinity is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(3.1f));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(new AtomicInteger(3))); // not supported
-        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
-    }
-
-    public void testToIntExact() {
-        assertEquals(3L, Numbers.toIntExact(Long.valueOf(3L)));
-        assertEquals(3L, Numbers.toIntExact(Integer.valueOf(3)));
-        assertEquals(3L, Numbers.toIntExact(Short.valueOf((short) 3)));
-        assertEquals(3L, Numbers.toIntExact(Byte.valueOf((byte) 3)));
-        assertEquals(3L, Numbers.toIntExact(3d));
-        assertEquals(3L, Numbers.toIntExact(3f));
-        assertEquals(3L, Numbers.toIntExact(BigInteger.valueOf(3L)));
-        assertEquals(3L, Numbers.toIntExact(BigDecimal.valueOf(3L)));
-
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(3.1d));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
-        assertEquals("NaN is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
-        assertEquals("Infinity is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(3.1f));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toIntExact(1L << 40));
-        assertEquals("integer overflow", ae.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toIntExact(new AtomicInteger(3))); // not supported
-        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
-    }
-
-    public void testToShortExact() {
-        assertEquals(3L, Numbers.toShortExact(Long.valueOf(3L)));
-        assertEquals(3L, Numbers.toShortExact(Integer.valueOf(3)));
-        assertEquals(3L, Numbers.toShortExact(Short.valueOf((short) 3)));
-        assertEquals(3L, Numbers.toShortExact(Byte.valueOf((byte) 3)));
-        assertEquals(3L, Numbers.toShortExact(3d));
-        assertEquals(3L, Numbers.toShortExact(3f));
-        assertEquals(3L, Numbers.toShortExact(BigInteger.valueOf(3L)));
-        assertEquals(3L, Numbers.toShortExact(BigDecimal.valueOf(3L)));
-
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(3.1d));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
-        assertEquals("NaN is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
-        assertEquals("Infinity is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(3.1f));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toShortExact(100000));
-        assertEquals("short overflow: " + 100000, ae.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toShortExact(new AtomicInteger(3))); // not supported
-        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
-    }
-
-    public void testToByteExact() {
-        assertEquals(3L, Numbers.toByteExact(Long.valueOf(3L)));
-        assertEquals(3L, Numbers.toByteExact(Integer.valueOf(3)));
-        assertEquals(3L, Numbers.toByteExact(Short.valueOf((short) 3)));
-        assertEquals(3L, Numbers.toByteExact(Byte.valueOf((byte) 3)));
-        assertEquals(3L, Numbers.toByteExact(3d));
-        assertEquals(3L, Numbers.toByteExact(3f));
-        assertEquals(3L, Numbers.toByteExact(BigInteger.valueOf(3L)));
-        assertEquals(3L, Numbers.toByteExact(BigDecimal.valueOf(3L)));
-
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(3.1d));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.NaN));
-        assertEquals("NaN is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toLongExact(Double.POSITIVE_INFINITY));
-        assertEquals("Infinity is not an integer value", e.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(3.1f));
-        assertEquals("3.1 is not an integer value", e.getMessage());
-        ArithmeticException ae = expectThrows(ArithmeticException.class, () -> Numbers.toByteExact(300));
-        assertEquals("byte overflow: " + 300, ae.getMessage());
-        e = expectThrows(IllegalArgumentException.class, () -> Numbers.toByteExact(new AtomicInteger(3))); // not supported
-        assertEquals("Cannot check whether [3] of class [java.util.concurrent.atomic.AtomicInteger] is actually a long", e.getMessage());
-    }
-}
diff --git a/server/src/test/java/org/opensearch/common/RoundingTests.java b/server/src/test/java/org/opensearch/common/RoundingTests.java
index e0c44e3516e7b..0ebfe02dc7641 100644
--- a/server/src/test/java/org/opensearch/common/RoundingTests.java
+++ b/server/src/test/java/org/opensearch/common/RoundingTests.java
@@ -1143,6 +1143,28 @@ public void testNonMillisecondsBasedUnitCalendarRoundingSize() {
         assertThat(prepared.roundingSize(thirdQuarter, Rounding.DateTimeUnit.HOUR_OF_DAY), closeTo(2208.0, 0.000001));
     }
 
+    public void testArrayRoundingImplementations() {
+        int length = randomIntBetween(1, 256);
+        long[] values = new long[length];
+        for (int i = 1; i < values.length; i++) {
+            values[i] = values[i - 1] + (randomNonNegativeLong() % 100);
+        }
+
+        Rounding.Prepared binarySearchImpl = new Rounding.BinarySearchArrayRounding(values, length, null);
+        Rounding.Prepared linearSearchImpl = new Rounding.BidirectionalLinearSearchArrayRounding(values, length, null);
+
+        for (int i = 0; i < 100000; i++) {
+            long key = values[0] + (randomNonNegativeLong() % (100 + values[length - 1] - values[0]));
+            assertEquals(binarySearchImpl.round(key), linearSearchImpl.round(key));
+        }
+
+        AssertionError exception = expectThrows(AssertionError.class, () -> { binarySearchImpl.round(values[0] - 1); });
+        assertEquals("utcMillis must be after " + values[0], exception.getMessage());
+
+        exception = expectThrows(AssertionError.class, () -> { linearSearchImpl.round(values[0] - 1); });
+        assertEquals("utcMillis must be after " + values[0], exception.getMessage());
+    }
+
     private void assertInterval(long rounded, long nextRoundingValue, Rounding rounding, int minutes, ZoneId tz) {
         assertInterval(rounded, dateBetween(rounded, nextRoundingValue), nextRoundingValue, rounding, tz);
         long millisPerMinute = 60_000;
diff --git a/server/src/test/java/org/opensearch/common/RoundingWireTests.java b/server/src/test/java/org/opensearch/common/RoundingWireTests.java
index 12de67d3a56c2..4e51c0457b564 100644
--- a/server/src/test/java/org/opensearch/common/RoundingWireTests.java
+++ b/server/src/test/java/org/opensearch/common/RoundingWireTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.common;
 
 import org.opensearch.common.Rounding.DateTimeUnit;
-import org.opensearch.common.io.stream.Writeable.Reader;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 public class RoundingWireTests extends AbstractWireSerializingTestCase<Rounding> {
diff --git a/server/src/test/java/org/opensearch/common/UUIDTests.java b/server/src/test/java/org/opensearch/common/UUIDTests.java
index a71b68bfe859e..1db6d2b415147 100644
--- a/server/src/test/java/org/opensearch/common/UUIDTests.java
+++ b/server/src/test/java/org/opensearch/common/UUIDTests.java
@@ -45,8 +45,8 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.common.lucene.Lucene;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
diff --git a/server/src/test/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainerTests.java b/server/src/test/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainerTests.java
new file mode 100644
index 0000000000000..1780819390052
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/AsyncMultiStreamEncryptedBlobContainerTests.java
@@ -0,0 +1,125 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore;
+
+import org.opensearch.common.Randomness;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.read.listener.ListenerTestUtils;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.DecryptedRangedStreamProvider;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.UnaryOperator;
+
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class AsyncMultiStreamEncryptedBlobContainerTests extends OpenSearchTestCase {
+
+    // Tests the happy path scenario for decrypting a read context
+    @SuppressWarnings("unchecked")
+    public void testReadBlobAsync() throws Exception {
+        String testBlobName = "testBlobName";
+        int size = 100;
+
+        // Mock objects needed for the test
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        CryptoHandler<Object, Object> cryptoHandler = mock(CryptoHandler.class);
+        Object cryptoContext = mock(Object.class);
+        when(cryptoHandler.loadEncryptionMetadata(any())).thenReturn(cryptoContext);
+        when(cryptoHandler.estimateDecryptedLength(any(), anyLong())).thenReturn((long) size);
+        long[] adjustedRanges = { 0, size - 1 };
+        DecryptedRangedStreamProvider rangedStreamProvider = new DecryptedRangedStreamProvider(adjustedRanges, UnaryOperator.identity());
+        when(cryptoHandler.createDecryptingStreamOfRange(eq(cryptoContext), anyLong(), anyLong())).thenReturn(rangedStreamProvider);
+
+        // Objects needed for API call
+        final byte[] data = new byte[size];
+        Randomness.get().nextBytes(data);
+
+        final InputStreamContainer inputStreamContainer = new InputStreamContainer(new ByteArrayInputStream(data), data.length, 0);
+        final ListenerTestUtils.CountingCompletionListener<ReadContext> completionListener =
+            new ListenerTestUtils.CountingCompletionListener<>();
+        final CompletableFuture<InputStreamContainer> streamContainerFuture = CompletableFuture.completedFuture(inputStreamContainer);
+        final ReadContext readContext = new ReadContext(size, List.of(() -> streamContainerFuture), null);
+
+        Mockito.doAnswer(invocation -> {
+            ActionListener<ReadContext> readContextActionListener = invocation.getArgument(1);
+            readContextActionListener.onResponse(readContext);
+            return null;
+        }).when(blobContainer).readBlobAsync(eq(testBlobName), any());
+
+        AsyncMultiStreamEncryptedBlobContainer<Object, Object> asyncMultiStreamEncryptedBlobContainer =
+            new AsyncMultiStreamEncryptedBlobContainer<>(blobContainer, cryptoHandler);
+        asyncMultiStreamEncryptedBlobContainer.readBlobAsync(testBlobName, completionListener);
+
+        // Assert results
+        ReadContext response = completionListener.getResponse();
+        assertEquals(0, completionListener.getFailureCount());
+        assertEquals(1, completionListener.getResponseCount());
+        assertNull(completionListener.getException());
+
+        assertTrue(response instanceof AsyncMultiStreamEncryptedBlobContainer.DecryptedReadContext);
+        assertEquals(1, response.getNumberOfParts());
+        assertEquals(size, response.getBlobSize());
+
+        InputStreamContainer responseContainer = response.getPartStreams().get(0).get().join();
+        assertEquals(0, responseContainer.getOffset());
+        assertEquals(size, responseContainer.getContentLength());
+        assertEquals(100, responseContainer.getInputStream().available());
+    }
+
+    // Tests the exception scenario for decrypting a read context
+    @SuppressWarnings("unchecked")
+    public void testReadBlobAsyncException() throws Exception {
+        String testBlobName = "testBlobName";
+        int size = 100;
+
+        // Mock objects needed for the test
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        CryptoHandler<Object, Object> cryptoHandler = mock(CryptoHandler.class);
+        when(cryptoHandler.loadEncryptionMetadata(any())).thenThrow(new IOException());
+
+        // Objects needed for API call
+        final byte[] data = new byte[size];
+        Randomness.get().nextBytes(data);
+        final InputStreamContainer inputStreamContainer = new InputStreamContainer(new ByteArrayInputStream(data), data.length, 0);
+        final ListenerTestUtils.CountingCompletionListener<ReadContext> completionListener =
+            new ListenerTestUtils.CountingCompletionListener<>();
+        final CompletableFuture<InputStreamContainer> streamContainerFuture = CompletableFuture.completedFuture(inputStreamContainer);
+        final ReadContext readContext = new ReadContext(size, List.of(() -> streamContainerFuture), null);
+
+        Mockito.doAnswer(invocation -> {
+            ActionListener<ReadContext> readContextActionListener = invocation.getArgument(1);
+            readContextActionListener.onResponse(readContext);
+            return null;
+        }).when(blobContainer).readBlobAsync(eq(testBlobName), any());
+
+        AsyncMultiStreamEncryptedBlobContainer<Object, Object> asyncMultiStreamEncryptedBlobContainer =
+            new AsyncMultiStreamEncryptedBlobContainer<>(blobContainer, cryptoHandler);
+        asyncMultiStreamEncryptedBlobContainer.readBlobAsync(testBlobName, completionListener);
+
+        // Assert results
+        assertEquals(1, completionListener.getFailureCount());
+        assertEquals(0, completionListener.getResponseCount());
+        assertNull(completionListener.getResponse());
+        assertTrue(completionListener.getException() instanceof IOException);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/fs/FsBlobContainerTests.java b/server/src/test/java/org/opensearch/common/blobstore/fs/FsBlobContainerTests.java
index 83f5c0445e21d..f8a8f9cefacf5 100644
--- a/server/src/test/java/org/opensearch/common/blobstore/fs/FsBlobContainerTests.java
+++ b/server/src/test/java/org/opensearch/common/blobstore/fs/FsBlobContainerTests.java
@@ -34,11 +34,14 @@
 import org.apache.lucene.tests.mockfile.FilterFileSystemProvider;
 import org.apache.lucene.tests.mockfile.FilterSeekableByteChannel;
 import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.io.Streams;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
@@ -54,10 +57,14 @@
 import java.nio.file.Path;
 import java.nio.file.attribute.FileAttribute;
 import java.nio.file.spi.FileSystemProvider;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
@@ -118,6 +125,79 @@ public void testIsTempBlobName() {
         assertThat(FsBlobContainer.isTempBlobName(tempBlobName), is(true));
     }
 
+    private void testListBlobsByPrefixInSortedOrder(int limit, BlobContainer.BlobNameSortOrder blobNameSortOrder) throws IOException {
+
+        final Path path = PathUtils.get(createTempDir().toString());
+
+        List<String> blobsInFileSystem = new ArrayList<>();
+        for (int i = 0; i < 10; i++) {
+            final String blobName = randomAlphaOfLengthBetween(10, 20).toLowerCase(Locale.ROOT);
+            final byte[] blobData = randomByteArrayOfLength(randomIntBetween(1, frequently() ? 512 : 1 << 20)); // rarely up to 1mb
+            Files.write(path.resolve(blobName), blobData);
+            blobsInFileSystem.add(blobName);
+        }
+
+        final FsBlobContainer container = new FsBlobContainer(
+            new FsBlobStore(randomIntBetween(1, 8) * 1024, path, false),
+            BlobPath.cleanPath(),
+            path
+        );
+
+        if (limit >= 0) {
+            container.listBlobsByPrefixInSortedOrder(null, limit, blobNameSortOrder, new ActionListener<>() {
+                @Override
+                public void onResponse(List<BlobMetadata> blobMetadata) {
+                    int actualLimit = Math.min(limit, 10);
+                    assertEquals(actualLimit, blobMetadata.size());
+
+                    if (blobNameSortOrder == BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC) {
+                        blobsInFileSystem.sort(String::compareTo);
+                    } else {
+                        blobsInFileSystem.sort(Collections.reverseOrder(String::compareTo));
+                    }
+                    List<String> keys = blobsInFileSystem.subList(0, actualLimit);
+                    assertEquals(keys, blobMetadata.stream().map(BlobMetadata::name).collect(Collectors.toList()));
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    fail("blobContainer.listBlobsByPrefixInLexicographicOrder failed with exception: " + e.getMessage());
+                }
+            });
+        } else {
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> container.listBlobsByPrefixInSortedOrder(null, limit, blobNameSortOrder, new ActionListener<>() {
+                    @Override
+                    public void onResponse(List<BlobMetadata> blobMetadata) {}
+
+                    @Override
+                    public void onFailure(Exception e) {}
+                })
+            );
+        }
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithNegativeLimit() throws IOException {
+        testListBlobsByPrefixInSortedOrder(-5, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithZeroLimit() throws IOException {
+        testListBlobsByPrefixInSortedOrder(0, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitLessThanNumberOfRecords() throws IOException {
+        testListBlobsByPrefixInSortedOrder(8, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitNumberOfRecords() throws IOException {
+        testListBlobsByPrefixInSortedOrder(10, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
+    public void testListBlobsByPrefixInLexicographicOrderWithLimitGreaterThanNumberOfRecords() throws IOException {
+        testListBlobsByPrefixInSortedOrder(12, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC);
+    }
+
     static class MockFileSystemProvider extends FilterFileSystemProvider {
 
         final Consumer<Long> onRead;
diff --git a/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriterTests.java b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriterTests.java
new file mode 100644
index 0000000000000..f2a758b9bbe10
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/FilePartWriterTests.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read.listener;
+
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.UUID;
+import java.util.function.UnaryOperator;
+
+public class FilePartWriterTests extends OpenSearchTestCase {
+
+    private Path path;
+
+    @Before
+    public void init() throws Exception {
+        path = createTempDir("FilePartWriterTests");
+    }
+
+    public void testFilePartWriter() throws Exception {
+        Path segmentFilePath = path.resolve(UUID.randomUUID().toString());
+        int contentLength = 100;
+        InputStream inputStream = new ByteArrayInputStream(randomByteArrayOfLength(contentLength));
+        InputStreamContainer inputStreamContainer = new InputStreamContainer(inputStream, inputStream.available(), 0);
+
+        FilePartWriter.write(segmentFilePath, inputStreamContainer, UnaryOperator.identity());
+
+        assertTrue(Files.exists(segmentFilePath));
+        assertEquals(contentLength, Files.size(segmentFilePath));
+    }
+
+    public void testFilePartWriterWithOffset() throws Exception {
+        Path segmentFilePath = path.resolve(UUID.randomUUID().toString());
+        int contentLength = 100;
+        int offset = 10;
+        InputStream inputStream = new ByteArrayInputStream(randomByteArrayOfLength(contentLength));
+        InputStreamContainer inputStreamContainer = new InputStreamContainer(inputStream, inputStream.available(), offset);
+
+        FilePartWriter.write(segmentFilePath, inputStreamContainer, UnaryOperator.identity());
+
+        assertTrue(Files.exists(segmentFilePath));
+        assertEquals(contentLength + offset, Files.size(segmentFilePath));
+    }
+
+    public void testFilePartWriterLargeInput() throws Exception {
+        Path segmentFilePath = path.resolve(UUID.randomUUID().toString());
+        int contentLength = 20 * 1024 * 1024;
+        InputStream inputStream = new ByteArrayInputStream(randomByteArrayOfLength(contentLength));
+        InputStreamContainer inputStreamContainer = new InputStreamContainer(inputStream, contentLength, 0);
+
+        FilePartWriter.write(segmentFilePath, inputStreamContainer, UnaryOperator.identity());
+
+        assertTrue(Files.exists(segmentFilePath));
+        assertEquals(contentLength, Files.size(segmentFilePath));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ListenerTestUtils.java b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ListenerTestUtils.java
new file mode 100644
index 0000000000000..a3a32f6db2148
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ListenerTestUtils.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read.listener;
+
+import org.opensearch.core.action.ActionListener;
+
+/**
+ * Utility class containing common functionality for read listener based tests
+ */
+public class ListenerTestUtils {
+
+    /**
+     * CountingCompletionListener acts as a verification instance for wrapping listener based calls.
+     * Keeps track of the last response, failure and count of response and failure invocations.
+     */
+    public static class CountingCompletionListener<T> implements ActionListener<T> {
+        private int responseCount;
+        private int failureCount;
+        private T response;
+        private Exception exception;
+
+        @Override
+        public void onResponse(T response) {
+            this.response = response;
+            responseCount++;
+        }
+
+        @Override
+        public void onFailure(Exception e) {
+            exception = e;
+            failureCount++;
+        }
+
+        public int getResponseCount() {
+            return responseCount;
+        }
+
+        public int getFailureCount() {
+            return failureCount;
+        }
+
+        public T getResponse() {
+            return response;
+        }
+
+        public Exception getException() {
+            return exception;
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListenerTests.java b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListenerTests.java
new file mode 100644
index 0000000000000..0163c2275e7f4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/stream/read/listener/ReadContextListenerTests.java
@@ -0,0 +1,229 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.stream.read.listener;
+
+import org.apache.lucene.tests.util.LuceneTestCase.SuppressFileSystems;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.function.UnaryOperator;
+
+import static org.opensearch.common.blobstore.stream.read.listener.ListenerTestUtils.CountingCompletionListener;
+
+/*
+    WindowsFS tries to simulate file handles in a best case simulation.
+    The deletion for the open file on an actual Windows system will be performed as soon as the last handle
+    is closed, which this simulation does not account for. Preventing use of WindowsFS for these tests.
+ */
+@SuppressFileSystems("WindowsFS")
+public class ReadContextListenerTests extends OpenSearchTestCase {
+
+    private Path path;
+    private static ThreadPool threadPool;
+    private static final int NUMBER_OF_PARTS = 5;
+    private static final int PART_SIZE = 10;
+    private static final String TEST_SEGMENT_FILE = "test_segment_file";
+    private static final int MAX_CONCURRENT_STREAMS = 10;
+
+    @BeforeClass
+    public static void setup() {
+        threadPool = new TestThreadPool(ReadContextListenerTests.class.getName());
+    }
+
+    @AfterClass
+    public static void cleanup() {
+        threadPool.shutdown();
+    }
+
+    @Before
+    public void init() throws Exception {
+        path = createTempDir("ReadContextListenerTests");
+    }
+
+    public void testReadContextListener() throws InterruptedException, IOException {
+        Path fileLocation = path.resolve(UUID.randomUUID().toString());
+        List<ReadContext.StreamPartCreator> blobPartStreams = initializeBlobPartStreams();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new LatchedActionListener<>(new PlainActionFuture<>(), countDownLatch);
+        ReadContextListener readContextListener = new ReadContextListener(
+            TEST_SEGMENT_FILE,
+            fileLocation,
+            completionListener,
+            threadPool,
+            UnaryOperator.identity(),
+            MAX_CONCURRENT_STREAMS
+        );
+        ReadContext readContext = new ReadContext((long) PART_SIZE * NUMBER_OF_PARTS, blobPartStreams, null);
+        readContextListener.onResponse(readContext);
+
+        countDownLatch.await();
+
+        assertTrue(Files.exists(fileLocation));
+        assertEquals(NUMBER_OF_PARTS * PART_SIZE, Files.size(fileLocation));
+    }
+
+    public void testReadContextListenerFailure() throws Exception {
+        Path fileLocation = path.resolve(UUID.randomUUID().toString());
+        List<ReadContext.StreamPartCreator> blobPartStreams = initializeBlobPartStreams();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new LatchedActionListener<>(new PlainActionFuture<>(), countDownLatch);
+        ReadContextListener readContextListener = new ReadContextListener(
+            TEST_SEGMENT_FILE,
+            fileLocation,
+            completionListener,
+            threadPool,
+            UnaryOperator.identity(),
+            MAX_CONCURRENT_STREAMS
+        );
+        InputStream badInputStream = new InputStream() {
+
+            @Override
+            public int read(byte[] b, int off, int len) throws IOException {
+                return read();
+            }
+
+            @Override
+            public int read() throws IOException {
+                throw new IOException();
+            }
+
+            @Override
+            public int available() {
+                return PART_SIZE;
+            }
+        };
+
+        blobPartStreams.add(
+            NUMBER_OF_PARTS,
+            () -> CompletableFuture.supplyAsync(
+                () -> new InputStreamContainer(badInputStream, PART_SIZE, PART_SIZE * NUMBER_OF_PARTS),
+                threadPool.generic()
+            )
+        );
+        ReadContext readContext = new ReadContext((long) (PART_SIZE + 1) * NUMBER_OF_PARTS, blobPartStreams, null);
+        readContextListener.onResponse(readContext);
+
+        countDownLatch.await();
+        assertFalse(Files.exists(fileLocation));
+        assertFalse(Files.exists(readContextListener.getTmpFileLocation()));
+    }
+
+    public void testReadContextListenerException() {
+        Path fileLocation = path.resolve(UUID.randomUUID().toString());
+        CountingCompletionListener<String> listener = new CountingCompletionListener<String>();
+        ReadContextListener readContextListener = new ReadContextListener(
+            TEST_SEGMENT_FILE,
+            fileLocation,
+            listener,
+            threadPool,
+            UnaryOperator.identity(),
+            MAX_CONCURRENT_STREAMS
+        );
+        IOException exception = new IOException();
+        readContextListener.onFailure(exception);
+        assertEquals(1, listener.getFailureCount());
+        assertEquals(exception, listener.getException());
+    }
+
+    public void testWriteToTempFile() throws Exception {
+        final String fileName = UUID.randomUUID().toString();
+        Path fileLocation = path.resolve(fileName);
+        List<ReadContext.StreamPartCreator> blobPartStreams = initializeBlobPartStreams();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new LatchedActionListener<>(new PlainActionFuture<>(), countDownLatch);
+        ReadContextListener readContextListener = new ReadContextListener(
+            TEST_SEGMENT_FILE,
+            fileLocation,
+            completionListener,
+            threadPool,
+            UnaryOperator.identity(),
+            MAX_CONCURRENT_STREAMS
+        );
+        ByteArrayInputStream assertingStream = new ByteArrayInputStream(randomByteArrayOfLength(PART_SIZE)) {
+            @Override
+            public int read(byte[] b) throws IOException {
+                assertTrue("parts written to temp file location", Files.exists(readContextListener.getTmpFileLocation()));
+                return super.read(b);
+            }
+        };
+        blobPartStreams.add(
+            NUMBER_OF_PARTS,
+            () -> CompletableFuture.supplyAsync(
+                () -> new InputStreamContainer(assertingStream, PART_SIZE, PART_SIZE * NUMBER_OF_PARTS),
+                threadPool.generic()
+            )
+        );
+        ReadContext readContext = new ReadContext((long) (PART_SIZE + 1) * NUMBER_OF_PARTS + 1, blobPartStreams, null);
+        readContextListener.onResponse(readContext);
+
+        countDownLatch.await();
+        assertTrue(Files.exists(fileLocation));
+        assertFalse(Files.exists(readContextListener.getTmpFileLocation()));
+    }
+
+    public void testWriteToTempFile_alreadyExists_replacesFile() throws Exception {
+        final String fileName = UUID.randomUUID().toString();
+        Path fileLocation = path.resolve(fileName);
+        // create an empty file at location.
+        Files.createFile(fileLocation);
+        assertEquals(0, Files.readAllBytes(fileLocation).length);
+        List<ReadContext.StreamPartCreator> blobPartStreams = initializeBlobPartStreams();
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new LatchedActionListener<>(new PlainActionFuture<>(), countDownLatch);
+        ReadContextListener readContextListener = new ReadContextListener(
+            TEST_SEGMENT_FILE,
+            fileLocation,
+            completionListener,
+            threadPool,
+            UnaryOperator.identity(),
+            MAX_CONCURRENT_STREAMS
+        );
+        ReadContext readContext = new ReadContext((long) (PART_SIZE + 1) * NUMBER_OF_PARTS, blobPartStreams, null);
+        readContextListener.onResponse(readContext);
+
+        countDownLatch.await();
+        assertTrue(Files.exists(fileLocation));
+        assertEquals(50, Files.readAllBytes(fileLocation).length);
+        assertFalse(Files.exists(readContextListener.getTmpFileLocation()));
+    }
+
+    private List<ReadContext.StreamPartCreator> initializeBlobPartStreams() {
+        List<ReadContext.StreamPartCreator> blobPartStreams = new ArrayList<>();
+        for (int partNumber = 0; partNumber < NUMBER_OF_PARTS; partNumber++) {
+            InputStream testStream = new ByteArrayInputStream(randomByteArrayOfLength(PART_SIZE));
+            int finalPartNumber = partNumber;
+            blobPartStreams.add(
+                () -> CompletableFuture.supplyAsync(
+                    () -> new InputStreamContainer(testStream, PART_SIZE, (long) finalPartNumber * PART_SIZE),
+                    threadPool.generic()
+                )
+            );
+        }
+        return blobPartStreams;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainerTests.java b/server/src/test/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainerTests.java
new file mode 100644
index 0000000000000..a33e5f453d1e1
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/transfer/RemoteTransferContainerTests.java
@@ -0,0 +1,216 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer;
+
+import org.opensearch.common.StreamContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeFileInputStream;
+import org.opensearch.common.blobstore.transfer.stream.OffsetRangeInputStream;
+import org.opensearch.common.blobstore.transfer.stream.ResettableCheckedInputStream;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.UUID;
+
+public class RemoteTransferContainerTests extends OpenSearchTestCase {
+
+    private static final int TEST_FILE_SIZE_BYTES = 128;
+
+    private Path testFile;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(TEST_FILE_SIZE_BYTES), StandardOpenOption.APPEND);
+    }
+
+    public void testSupplyStreamContextDivisibleParts() throws IOException, InterruptedException {
+        try (
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                testFile.getFileName().toString(),
+                testFile.getFileName().toString(),
+                TEST_FILE_SIZE_BYTES,
+                true,
+                WritePriority.HIGH,
+                new RemoteTransferContainer.OffsetRangeInputStreamSupplier() {
+                    @Override
+                    public OffsetRangeInputStream get(long size, long position) throws IOException {
+                        return new OffsetRangeFileInputStream(testFile, size, position);
+                    }
+                },
+                0,
+                false
+            )
+        ) {
+            testSupplyStreamContext(remoteTransferContainer, 16, 16, 8);
+        }
+    }
+
+    public void testSupplyStreamContextNonDivisibleParts() throws IOException, InterruptedException {
+        try (
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                testFile.getFileName().toString(),
+                testFile.getFileName().toString(),
+                TEST_FILE_SIZE_BYTES,
+                true,
+                WritePriority.HIGH,
+                new RemoteTransferContainer.OffsetRangeInputStreamSupplier() {
+                    @Override
+                    public OffsetRangeInputStream get(long size, long position) throws IOException {
+                        return new OffsetRangeFileInputStream(testFile, size, position);
+                    }
+                },
+                0,
+                false
+            )
+        ) {
+            testSupplyStreamContext(remoteTransferContainer, 10, 8, 13);
+        }
+    }
+
+    private void testSupplyStreamContext(
+        RemoteTransferContainer remoteTransferContainer,
+        long partSize,
+        long lastPartSize,
+        int expectedPartCount
+    ) throws InterruptedException {
+        StreamContext streamContext = remoteTransferContainer.supplyStreamContext(partSize);
+        int partCount = streamContext.getNumberOfParts();
+        assertEquals(expectedPartCount, partCount);
+        Thread[] threads = new Thread[partCount];
+        long totalContentLength = remoteTransferContainer.getContentLength();
+        assert partSize * (partCount - 1) + lastPartSize == totalContentLength
+            : "part sizes and last part size don't add up to total content length";
+        logger.info("partSize: {}, lastPartSize: {}, partCount: {}", partSize, lastPartSize, streamContext.getNumberOfParts());
+        for (int partIdx = 0; partIdx < partCount; partIdx++) {
+            int finalPartIdx = partIdx;
+            long expectedPartSize = (partIdx == partCount - 1) ? lastPartSize : partSize;
+            threads[partIdx] = new Thread(() -> {
+                try {
+                    InputStreamContainer inputStreamContainer = streamContext.provideStream(finalPartIdx);
+                    assertEquals(expectedPartSize, inputStreamContainer.getContentLength());
+                } catch (IOException e) {
+                    fail("IOException during stream creation");
+                }
+            });
+            threads[partIdx].start();
+        }
+        for (int i = 0; i < partCount; i++) {
+            threads[i].join();
+        }
+    }
+
+    public void testSupplyStreamContextCalledTwice() throws IOException {
+        try (
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                testFile.getFileName().toString(),
+                testFile.getFileName().toString(),
+                TEST_FILE_SIZE_BYTES,
+                true,
+                WritePriority.HIGH,
+                new RemoteTransferContainer.OffsetRangeInputStreamSupplier() {
+                    @Override
+                    public OffsetRangeInputStream get(long size, long position) throws IOException {
+                        return new OffsetRangeFileInputStream(testFile, size, position);
+                    }
+                },
+                0,
+                false
+            )
+        ) {
+            remoteTransferContainer.supplyStreamContext(16);
+            assertThrows(RuntimeException.class, () -> remoteTransferContainer.supplyStreamContext(16));
+        }
+    }
+
+    public void testTypeOfProvidedStreamsAllCases() throws IOException {
+        testTypeOfProvidedStreams(true);
+        testTypeOfProvidedStreams(false);
+    }
+
+    public void testCreateWriteContextAllCases() throws IOException {
+        testCreateWriteContext(true);
+        testCreateWriteContext(false);
+    }
+
+    private void testCreateWriteContext(boolean doRemoteDataIntegrityCheck) throws IOException {
+        String remoteFileName = testFile.getFileName().toString() + UUID.randomUUID();
+        Long expectedChecksum = randomLong();
+        try (
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                testFile.getFileName().toString(),
+                remoteFileName,
+                TEST_FILE_SIZE_BYTES,
+                true,
+                WritePriority.HIGH,
+                new RemoteTransferContainer.OffsetRangeInputStreamSupplier() {
+                    @Override
+                    public OffsetRangeInputStream get(long size, long position) throws IOException {
+                        return new OffsetRangeFileInputStream(testFile, size, position);
+                    }
+                },
+                expectedChecksum,
+                doRemoteDataIntegrityCheck
+            )
+        ) {
+            WriteContext writeContext = remoteTransferContainer.createWriteContext();
+            assertEquals(remoteFileName, writeContext.getFileName());
+            assertTrue(writeContext.isFailIfAlreadyExists());
+            assertEquals(TEST_FILE_SIZE_BYTES, writeContext.getFileSize());
+            assertEquals(WritePriority.HIGH, writeContext.getWritePriority());
+            assertEquals(doRemoteDataIntegrityCheck, writeContext.doRemoteDataIntegrityCheck());
+            if (doRemoteDataIntegrityCheck) {
+                assertEquals(expectedChecksum, writeContext.getExpectedChecksum());
+            } else {
+                assertNull(writeContext.getExpectedChecksum());
+            }
+        }
+    }
+
+    private void testTypeOfProvidedStreams(boolean isRemoteDataIntegritySupported) throws IOException {
+        try (
+            RemoteTransferContainer remoteTransferContainer = new RemoteTransferContainer(
+                testFile.getFileName().toString(),
+                testFile.getFileName().toString(),
+                TEST_FILE_SIZE_BYTES,
+                true,
+                WritePriority.HIGH,
+                new RemoteTransferContainer.OffsetRangeInputStreamSupplier() {
+                    @Override
+                    public OffsetRangeInputStream get(long size, long position) throws IOException {
+                        return new OffsetRangeFileInputStream(testFile, size, position);
+                    }
+                },
+                0,
+                isRemoteDataIntegritySupported
+            )
+        ) {
+            StreamContext streamContext = remoteTransferContainer.supplyStreamContext(16);
+            InputStreamContainer inputStreamContainer = streamContext.provideStream(0);
+            if (shouldOffsetInputStreamsBeChecked(isRemoteDataIntegritySupported)) {
+                assertTrue(inputStreamContainer.getInputStream() instanceof ResettableCheckedInputStream);
+            } else {
+                assertTrue(inputStreamContainer.getInputStream() instanceof OffsetRangeInputStream);
+            }
+            assertThrows(RuntimeException.class, () -> remoteTransferContainer.supplyStreamContext(16));
+        }
+    }
+
+    private boolean shouldOffsetInputStreamsBeChecked(boolean isRemoteDataIntegritySupported) {
+        return !isRemoteDataIntegritySupported;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStreamTests.java b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStreamTests.java
new file mode 100644
index 0000000000000..f7e093f8357cc
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeFileInputStreamTests.java
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import java.io.IOException;
+
+public class OffsetRangeFileInputStreamTests extends ResettableCheckedInputStreamBaseTest {
+
+    @Override
+    protected OffsetRangeInputStream getOffsetRangeInputStream(long size, long position) throws IOException {
+        return new OffsetRangeFileInputStream(testFile, size, position);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStreamTests.java b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStreamTests.java
new file mode 100644
index 0000000000000..7381d49bcdf99
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/OffsetRangeIndexInputStreamTests.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.NIOFSDirectory;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+
+public class OffsetRangeIndexInputStreamTests extends ResettableCheckedInputStreamBaseTest {
+
+    private Directory directory;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        directory = new NIOFSDirectory(testFile.getParent());
+    }
+
+    @Override
+    protected OffsetRangeInputStream getOffsetRangeInputStream(long size, long position) throws IOException {
+        return new OffsetRangeIndexInputStream(directory.openInput(testFile.getFileName().toString(), IOContext.DEFAULT), size, position);
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        directory.close();
+        super.tearDown();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStreamTests.java b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStreamTests.java
new file mode 100644
index 0000000000000..fc2eba4c35e2a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/RateLimitingOffsetRangeInputStreamTests.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.NIOFSDirectory;
+import org.apache.lucene.store.RateLimiter;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+
+public class RateLimitingOffsetRangeInputStreamTests extends ResettableCheckedInputStreamBaseTest {
+
+    private Directory directory;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        directory = new NIOFSDirectory(testFile.getParent());
+    }
+
+    @Override
+    protected OffsetRangeInputStream getOffsetRangeInputStream(long size, long position) throws IOException {
+        return new RateLimitingOffsetRangeInputStream(
+            new OffsetRangeIndexInputStream(directory.openInput(testFile.getFileName().toString(), IOContext.DEFAULT), size, position),
+            () -> new RateLimiter.SimpleRateLimiter(randomIntBetween(10, 20)),
+            (t) -> {}
+        );
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        directory.close();
+        super.tearDown();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStreamBaseTest.java b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStreamBaseTest.java
new file mode 100644
index 0000000000000..77763bfc78f26
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/blobstore/transfer/stream/ResettableCheckedInputStreamBaseTest.java
@@ -0,0 +1,180 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.blobstore.transfer.stream;
+
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+
+public abstract class ResettableCheckedInputStreamBaseTest extends OpenSearchTestCase {
+
+    private static final int TEST_FILE_SIZE_BYTES = 10;
+
+    private final byte[] bytesToWrite = randomByteArrayOfLength(TEST_FILE_SIZE_BYTES);
+    protected Path testFile;
+    private ResettableCheckedInputStream[] resettableCheckedInputStreams;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        testFile = createTempFile();
+        Files.write(testFile, bytesToWrite, StandardOpenOption.TRUNCATE_EXISTING);
+    }
+
+    protected abstract OffsetRangeInputStream getOffsetRangeInputStream(long size, long position) throws IOException;
+
+    public void testReadSingleByte() throws IOException, InterruptedException {
+        final int nParallelReads = 10;
+        Thread[] threads = new Thread[nParallelReads];
+        resettableCheckedInputStreams = new ResettableCheckedInputStream[nParallelReads];
+        for (int readIdx = 0; readIdx < nParallelReads; readIdx++) {
+            int offset = randomInt(TEST_FILE_SIZE_BYTES - 1);
+            OffsetRangeInputStream offsetRangeInputStream = getOffsetRangeInputStream(1, offset);
+            ResettableCheckedInputStream resettableCheckedInputStream = new ResettableCheckedInputStream(
+                offsetRangeInputStream,
+                testFile.getFileName().toString()
+            );
+            resettableCheckedInputStreams[readIdx] = resettableCheckedInputStream;
+            threads[readIdx] = new Thread(() -> {
+                try {
+                    assertEquals(bytesToWrite[offset], resettableCheckedInputStream.read());
+                } catch (IOException e) {
+                    fail("Failure while reading single byte from offset stream");
+                }
+            });
+            threads[readIdx].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+    }
+
+    public void testReadMultipleBytes() throws IOException, InterruptedException {
+        final int nParallelReads = 10;
+        Thread[] threads = new Thread[nParallelReads];
+        resettableCheckedInputStreams = new ResettableCheckedInputStream[nParallelReads];
+        for (int readIdx = 0; readIdx < nParallelReads; readIdx++) {
+            int readByteCount = randomInt(TEST_FILE_SIZE_BYTES - 1) + 1;
+            int offset = randomInt(TEST_FILE_SIZE_BYTES - readByteCount);
+            OffsetRangeInputStream offsetRangeInputStream = getOffsetRangeInputStream(readByteCount, offset);
+            ResettableCheckedInputStream resettableCheckedInputStream = new ResettableCheckedInputStream(
+                offsetRangeInputStream,
+                testFile.getFileName().toString()
+            );
+            resettableCheckedInputStreams[readIdx] = resettableCheckedInputStream;
+            threads[readIdx] = new Thread(() -> {
+                try {
+                    byte[] buffer = new byte[readByteCount];
+                    int bytesRead = resettableCheckedInputStream.read(buffer, 0, readByteCount);
+                    assertEquals(readByteCount, bytesRead);
+                    for (int bufferIdx = 0; bufferIdx < readByteCount; bufferIdx++) {
+                        assertEquals(bytesToWrite[offset + bufferIdx], buffer[bufferIdx]);
+                    }
+                } catch (IOException e) {
+                    fail("Failure while reading bytes from offset stream");
+                }
+            });
+            threads[readIdx].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+    }
+
+    public void testMarkAndReset() throws IOException, InterruptedException {
+        final int nParallelReads = 100;
+        Thread[] threads = new Thread[nParallelReads];
+        resettableCheckedInputStreams = new ResettableCheckedInputStream[nParallelReads];
+        for (int readIdx = 0; readIdx < nParallelReads; readIdx++) {
+            int readByteCount = randomInt(TEST_FILE_SIZE_BYTES - 1) + 1;
+            int offset = randomInt(TEST_FILE_SIZE_BYTES - readByteCount);
+            OffsetRangeInputStream offsetRangeInputStream = getOffsetRangeInputStream(readByteCount, offset);
+            ResettableCheckedInputStream resettableCheckedInputStream = new ResettableCheckedInputStream(
+                offsetRangeInputStream,
+                testFile.getFileName().toString()
+            );
+            resettableCheckedInputStreams[readIdx] = resettableCheckedInputStream;
+            threads[readIdx] = new Thread(() -> {
+                try {
+                    boolean streamMarked = false;
+                    long streamMarkPosition = -1;
+                    long streamMarkChecksum = -1;
+                    for (int byteIdx = 0; byteIdx < readByteCount - 1; byteIdx++) {
+                        resettableCheckedInputStream.read();
+                        if (!streamMarked && randomBoolean()) {
+                            streamMarked = true;
+                            streamMarkPosition = offsetRangeInputStream.getFilePointer();
+                            resettableCheckedInputStream.mark(readByteCount);
+                            streamMarkChecksum = resettableCheckedInputStream.getChecksum();
+                        }
+                    }
+                    if (!streamMarked) {
+                        streamMarkPosition = offsetRangeInputStream.getFilePointer();
+                        resettableCheckedInputStream.mark(readByteCount);
+                        streamMarkChecksum = resettableCheckedInputStream.getChecksum();
+                    }
+                    resettableCheckedInputStream.reset();
+                    assertEquals(streamMarkChecksum, resettableCheckedInputStream.getChecksum());
+                    assertEquals(bytesToWrite[(int) streamMarkPosition], resettableCheckedInputStream.read());
+                } catch (IOException e) {
+                    fail("Failure while reading bytes from offset stream");
+                }
+            });
+            threads[readIdx].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+    }
+
+    public void testReadAfterSkip() throws IOException {
+        OffsetRangeInputStream offsetRangeInputStream = getOffsetRangeInputStream(TEST_FILE_SIZE_BYTES, 0);
+        ResettableCheckedInputStream resettableCheckedInputStream = new ResettableCheckedInputStream(
+            offsetRangeInputStream,
+            testFile.getFileName().toString()
+        );
+        resettableCheckedInputStreams = new ResettableCheckedInputStream[] { resettableCheckedInputStream };
+
+        long skipBytes = randomLongBetween(1, TEST_FILE_SIZE_BYTES - 1);
+        long actualBytesSkipped = resettableCheckedInputStream.skip(skipBytes);
+        assertEquals(skipBytes, actualBytesSkipped);
+        assertEquals(bytesToWrite[(int) skipBytes], resettableCheckedInputStream.read());
+    }
+
+    public void testReadLastByte() throws IOException {
+        OffsetRangeInputStream offsetRangeInputStream = getOffsetRangeInputStream(TEST_FILE_SIZE_BYTES, 0);
+        ResettableCheckedInputStream resettableCheckedInputStream = new ResettableCheckedInputStream(
+            offsetRangeInputStream,
+            testFile.getFileName().toString()
+        );
+        resettableCheckedInputStreams = new ResettableCheckedInputStream[] { resettableCheckedInputStream };
+
+        long skipBytes = TEST_FILE_SIZE_BYTES;
+        long actualBytesSkipped = resettableCheckedInputStream.skip(skipBytes);
+        assertEquals(skipBytes, actualBytesSkipped);
+        assertEquals(-1, resettableCheckedInputStream.read());
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        for (ResettableCheckedInputStream resettableCheckedInputStream : resettableCheckedInputStreams) {
+            if (resettableCheckedInputStream != null) {
+                resettableCheckedInputStream.close();
+            }
+        }
+        super.tearDown();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/bytes/ByteBuffersBytesReferenceTests.java b/server/src/test/java/org/opensearch/common/bytes/ByteBuffersBytesReferenceTests.java
new file mode 100644
index 0000000000000..f05e293c33269
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/bytes/ByteBuffersBytesReferenceTests.java
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.bytes;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.hamcrest.Matchers;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.function.Function;
+
+public class ByteBuffersBytesReferenceTests extends AbstractBytesReferenceTestCase {
+    @ParametersFactory
+    public static Collection<Object[]> allocator() {
+        return Arrays.asList(
+            new Object[] { (Function<Integer, ByteBuffer>) ByteBuffer::allocateDirect },
+            new Object[] { (Function<Integer, ByteBuffer>) ByteBuffer::allocate }
+        );
+    }
+
+    private final Function<Integer, ByteBuffer> allocator;
+
+    public ByteBuffersBytesReferenceTests(Function<Integer, ByteBuffer> allocator) {
+        this.allocator = allocator;
+    }
+
+    @Override
+    protected BytesReference newBytesReference(int length) throws IOException {
+        return newBytesReference(length, randomInt(length));
+    }
+
+    @Override
+    protected BytesReference newBytesReferenceWithOffsetOfZero(int length) throws IOException {
+        return newBytesReference(length, 0);
+    }
+
+    private BytesReference newBytesReference(int length, int offset) throws IOException {
+        // we know bytes stream output always creates a paged bytes reference, we use it to create randomized content
+        final ByteBuffer buffer = allocator.apply(length + offset);
+        for (int i = 0; i < length + offset; i++) {
+            buffer.put((byte) random().nextInt(1 << 8));
+        }
+        assertEquals(length + offset, buffer.limit());
+        buffer.flip().position(offset);
+
+        BytesReference ref = BytesReference.fromByteBuffer(buffer);
+        assertEquals(length, ref.length());
+        assertTrue(ref instanceof BytesArray);
+        assertThat(ref.length(), Matchers.equalTo(length));
+        return ref;
+    }
+
+    public void testArray() throws IOException {
+        int[] sizes = { 0, randomInt(PAGE_SIZE), PAGE_SIZE, randomIntBetween(2, PAGE_SIZE * randomIntBetween(2, 5)) };
+
+        for (int i = 0; i < sizes.length; i++) {
+            BytesArray pbr = (BytesArray) newBytesReference(sizes[i]);
+            byte[] array = pbr.array();
+            assertNotNull(array);
+            assertEquals(sizes[i], array.length - pbr.offset());
+            assertSame(array, pbr.array());
+        }
+    }
+
+    public void testArrayOffset() throws IOException {
+        int length = randomInt(PAGE_SIZE * randomIntBetween(2, 5));
+        BytesArray pbr = (BytesArray) newBytesReferenceWithOffsetOfZero(length);
+        assertEquals(0, pbr.offset());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/bytes/BytesArrayTests.java b/server/src/test/java/org/opensearch/common/bytes/BytesArrayTests.java
index 9d3fd038f7d38..b7b03d2292e92 100644
--- a/server/src/test/java/org/opensearch/common/bytes/BytesArrayTests.java
+++ b/server/src/test/java/org/opensearch/common/bytes/BytesArrayTests.java
@@ -32,6 +32,8 @@
 package org.opensearch.common.bytes;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/bytes/CompositeBytesReferenceTests.java b/server/src/test/java/org/opensearch/common/bytes/CompositeBytesReferenceTests.java
index 0affae3b53465..2b9294873d012 100644
--- a/server/src/test/java/org/opensearch/common/bytes/CompositeBytesReferenceTests.java
+++ b/server/src/test/java/org/opensearch/common/bytes/CompositeBytesReferenceTests.java
@@ -36,6 +36,9 @@
 import org.apache.lucene.util.BytesRefIterator;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/bytes/PagedBytesReferenceTests.java b/server/src/test/java/org/opensearch/common/bytes/PagedBytesReferenceTests.java
index accbcb4b2d192..5cbc1ea9577c4 100644
--- a/server/src/test/java/org/opensearch/common/bytes/PagedBytesReferenceTests.java
+++ b/server/src/test/java/org/opensearch/common/bytes/PagedBytesReferenceTests.java
@@ -33,7 +33,10 @@
 package org.opensearch.common.bytes;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.util.ByteArray;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.PagedBytesReference;
+import org.opensearch.core.common.util.ByteArray;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/bytes/RecyclingBytesStreamOutputTests.java b/server/src/test/java/org/opensearch/common/bytes/RecyclingBytesStreamOutputTests.java
index 920684f06f83c..ede5658f0decd 100644
--- a/server/src/test/java/org/opensearch/common/bytes/RecyclingBytesStreamOutputTests.java
+++ b/server/src/test/java/org/opensearch/common/bytes/RecyclingBytesStreamOutputTests.java
@@ -36,7 +36,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/bytes/ReleasableBytesReferenceTests.java b/server/src/test/java/org/opensearch/common/bytes/ReleasableBytesReferenceTests.java
index 6b8ffdbd9b6ec..169c17c96f817 100644
--- a/server/src/test/java/org/opensearch/common/bytes/ReleasableBytesReferenceTests.java
+++ b/server/src/test/java/org/opensearch/common/bytes/ReleasableBytesReferenceTests.java
@@ -34,7 +34,10 @@
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
-import org.opensearch.common.util.ByteArray;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.util.ByteArray;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/cache/CacheTests.java b/server/src/test/java/org/opensearch/common/cache/CacheTests.java
index db497894c5883..5aa8faaa940d4 100644
--- a/server/src/test/java/org/opensearch/common/cache/CacheTests.java
+++ b/server/src/test/java/org/opensearch/common/cache/CacheTests.java
@@ -240,7 +240,7 @@ protected long now() {
         cache.setExpireAfterAccessNanos(1);
         List<Integer> evictedKeys = new ArrayList<>();
         cache.setRemovalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.EVICTED, notification.getRemovalReason());
+            assertEquals(RemovalReason.EVICTED, notification.getRemovalReason());
             evictedKeys.add(notification.getKey());
         });
         now.set(0);
@@ -299,7 +299,7 @@ protected long now() {
         cache.setExpireAfterWriteNanos(1);
         List<Integer> evictedKeys = new ArrayList<>();
         cache.setRemovalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.EVICTED, notification.getRemovalReason());
+            assertEquals(RemovalReason.EVICTED, notification.getRemovalReason());
             evictedKeys.add(notification.getKey());
         });
         now.set(0);
@@ -445,7 +445,7 @@ public void testInvalidate() {
     public void testNotificationOnInvalidate() {
         Set<Integer> notifications = new HashSet<>();
         Cache<Integer, String> cache = CacheBuilder.<Integer, String>builder().removalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.INVALIDATED, notification.getRemovalReason());
+            assertEquals(RemovalReason.INVALIDATED, notification.getRemovalReason());
             notifications.add(notification.getKey());
         }).build();
         for (int i = 0; i < numberOfEntries; i++) {
@@ -493,7 +493,7 @@ public void testInvalidateWithValue() {
     public void testNotificationOnInvalidateWithValue() {
         Set<Integer> notifications = new HashSet<>();
         Cache<Integer, String> cache = CacheBuilder.<Integer, String>builder().removalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.INVALIDATED, notification.getRemovalReason());
+            assertEquals(RemovalReason.INVALIDATED, notification.getRemovalReason());
             notifications.add(notification.getKey());
         }).build();
         for (int i = 0; i < numberOfEntries; i++) {
@@ -529,7 +529,7 @@ public void testInvalidateAll() {
     public void testNotificationOnInvalidateAll() {
         Set<Integer> notifications = new HashSet<>();
         Cache<Integer, String> cache = CacheBuilder.<Integer, String>builder().removalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.INVALIDATED, notification.getRemovalReason());
+            assertEquals(RemovalReason.INVALIDATED, notification.getRemovalReason());
             notifications.add(notification.getKey());
         }).build();
         Set<Integer> invalidated = new HashSet<>();
@@ -590,7 +590,7 @@ public int hashCode() {
     public void testNotificationOnReplace() {
         Set<Integer> notifications = new HashSet<>();
         Cache<Integer, String> cache = CacheBuilder.<Integer, String>builder().removalListener(notification -> {
-            assertEquals(RemovalNotification.RemovalReason.REPLACED, notification.getRemovalReason());
+            assertEquals(RemovalReason.REPLACED, notification.getRemovalReason());
             notifications.add(notification.getKey());
         }).build();
         for (int i = 0; i < numberOfEntries; i++) {
@@ -928,7 +928,7 @@ public void testRemoveUsingValuesIterator() {
         assertEquals(expectedRemovals.size(), removalNotifications.size());
         for (int i = 0; i < expectedRemovals.size(); i++) {
             assertEquals(expectedRemovals.get(i), removalNotifications.get(i).getValue());
-            assertEquals(RemovalNotification.RemovalReason.INVALIDATED, removalNotifications.get(i).getRemovalReason());
+            assertEquals(RemovalReason.INVALIDATED, removalNotifications.get(i).getRemovalReason());
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/collect/EvictingQueueTests.java b/server/src/test/java/org/opensearch/common/collect/EvictingQueueTests.java
index 9a9e0efcdb190..e976697bd59c8 100644
--- a/server/src/test/java/org/opensearch/common/collect/EvictingQueueTests.java
+++ b/server/src/test/java/org/opensearch/common/collect/EvictingQueueTests.java
@@ -29,7 +29,7 @@
 
 package org.opensearch.common.collect;
 
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/common/compress/DeflateCompressTests.java b/server/src/test/java/org/opensearch/common/compress/DeflateCompressTests.java
index f215817914ee0..262a7ec40a8f0 100644
--- a/server/src/test/java/org/opensearch/common/compress/DeflateCompressTests.java
+++ b/server/src/test/java/org/opensearch/common/compress/DeflateCompressTests.java
@@ -32,403 +32,18 @@
 
 package org.opensearch.common.compress;
 
-import org.apache.lucene.tests.util.LineFileDocs;
-import org.apache.lucene.tests.util.TestUtil;
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.nio.charset.StandardCharsets;
-import java.util.Random;
-import java.util.concurrent.CountDownLatch;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.test.core.compress.AbstractCompressorTestCase;
 
 /**
  * Test streaming compression (e.g. used for recovery)
  */
-public class DeflateCompressTests extends OpenSearchTestCase {
+public class DeflateCompressTests extends AbstractCompressorTestCase {
 
     private final Compressor compressor = new DeflateCompressor();
 
-    public void testRandom() throws IOException {
-        Random r = random();
-        for (int i = 0; i < 10; i++) {
-            byte bytes[] = new byte[TestUtil.nextInt(r, 1, 100000)];
-            r.nextBytes(bytes);
-            doTest(bytes);
-        }
-    }
-
-    public void testRandomThreads() throws Exception {
-        final Random r = random();
-        int threadCount = TestUtil.nextInt(r, 2, 6);
-        Thread[] threads = new Thread[threadCount];
-        final CountDownLatch startingGun = new CountDownLatch(1);
-        for (int tid = 0; tid < threadCount; tid++) {
-            final long seed = r.nextLong();
-            threads[tid] = new Thread() {
-                @Override
-                public void run() {
-                    try {
-                        Random r = new Random(seed);
-                        startingGun.await();
-                        for (int i = 0; i < 10; i++) {
-                            byte bytes[] = new byte[TestUtil.nextInt(r, 1, 100000)];
-                            r.nextBytes(bytes);
-                            doTest(bytes);
-                        }
-                    } catch (Exception e) {
-                        throw new RuntimeException(e);
-                    }
-                }
-            };
-            threads[tid].start();
-        }
-        startingGun.countDown();
-        for (Thread t : threads) {
-            t.join();
-        }
-    }
-
-    public void testLineDocs() throws IOException {
-        Random r = random();
-        LineFileDocs lineFileDocs = new LineFileDocs(r);
-        for (int i = 0; i < 10; i++) {
-            int numDocs = TestUtil.nextInt(r, 1, 200);
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-            for (int j = 0; j < numDocs; j++) {
-                String s = lineFileDocs.nextDoc().get("body");
-                bos.write(s.getBytes(StandardCharsets.UTF_8));
-            }
-            doTest(bos.toByteArray());
-        }
-        lineFileDocs.close();
-    }
-
-    public void testLineDocsThreads() throws Exception {
-        final Random r = random();
-        int threadCount = TestUtil.nextInt(r, 2, 6);
-        Thread[] threads = new Thread[threadCount];
-        final CountDownLatch startingGun = new CountDownLatch(1);
-        for (int tid = 0; tid < threadCount; tid++) {
-            final long seed = r.nextLong();
-            threads[tid] = new Thread() {
-                @Override
-                public void run() {
-                    try {
-                        Random r = new Random(seed);
-                        startingGun.await();
-                        LineFileDocs lineFileDocs = new LineFileDocs(r);
-                        for (int i = 0; i < 10; i++) {
-                            int numDocs = TestUtil.nextInt(r, 1, 200);
-                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                            for (int j = 0; j < numDocs; j++) {
-                                String s = lineFileDocs.nextDoc().get("body");
-                                bos.write(s.getBytes(StandardCharsets.UTF_8));
-                            }
-                            doTest(bos.toByteArray());
-                        }
-                        lineFileDocs.close();
-                    } catch (Exception e) {
-                        throw new RuntimeException(e);
-                    }
-                }
-            };
-            threads[tid].start();
-        }
-        startingGun.countDown();
-        for (Thread t : threads) {
-            t.join();
-        }
-    }
-
-    public void testRepetitionsL() throws IOException {
-        Random r = random();
-        for (int i = 0; i < 10; i++) {
-            int numLongs = TestUtil.nextInt(r, 1, 10000);
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-            long theValue = r.nextLong();
-            for (int j = 0; j < numLongs; j++) {
-                if (r.nextInt(10) == 0) {
-                    theValue = r.nextLong();
-                }
-                bos.write((byte) (theValue >>> 56));
-                bos.write((byte) (theValue >>> 48));
-                bos.write((byte) (theValue >>> 40));
-                bos.write((byte) (theValue >>> 32));
-                bos.write((byte) (theValue >>> 24));
-                bos.write((byte) (theValue >>> 16));
-                bos.write((byte) (theValue >>> 8));
-                bos.write((byte) theValue);
-            }
-            doTest(bos.toByteArray());
-        }
-    }
-
-    public void testRepetitionsLThreads() throws Exception {
-        final Random r = random();
-        int threadCount = TestUtil.nextInt(r, 2, 6);
-        Thread[] threads = new Thread[threadCount];
-        final CountDownLatch startingGun = new CountDownLatch(1);
-        for (int tid = 0; tid < threadCount; tid++) {
-            final long seed = r.nextLong();
-            threads[tid] = new Thread() {
-                @Override
-                public void run() {
-                    try {
-                        Random r = new Random(seed);
-                        startingGun.await();
-                        for (int i = 0; i < 10; i++) {
-                            int numLongs = TestUtil.nextInt(r, 1, 10000);
-                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                            long theValue = r.nextLong();
-                            for (int j = 0; j < numLongs; j++) {
-                                if (r.nextInt(10) == 0) {
-                                    theValue = r.nextLong();
-                                }
-                                bos.write((byte) (theValue >>> 56));
-                                bos.write((byte) (theValue >>> 48));
-                                bos.write((byte) (theValue >>> 40));
-                                bos.write((byte) (theValue >>> 32));
-                                bos.write((byte) (theValue >>> 24));
-                                bos.write((byte) (theValue >>> 16));
-                                bos.write((byte) (theValue >>> 8));
-                                bos.write((byte) theValue);
-                            }
-                            doTest(bos.toByteArray());
-                        }
-                    } catch (Exception e) {
-                        throw new RuntimeException(e);
-                    }
-                }
-            };
-            threads[tid].start();
-        }
-        startingGun.countDown();
-        for (Thread t : threads) {
-            t.join();
-        }
-    }
-
-    public void testRepetitionsI() throws IOException {
-        Random r = random();
-        for (int i = 0; i < 10; i++) {
-            int numInts = TestUtil.nextInt(r, 1, 20000);
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-            int theValue = r.nextInt();
-            for (int j = 0; j < numInts; j++) {
-                if (r.nextInt(10) == 0) {
-                    theValue = r.nextInt();
-                }
-                bos.write((byte) (theValue >>> 24));
-                bos.write((byte) (theValue >>> 16));
-                bos.write((byte) (theValue >>> 8));
-                bos.write((byte) theValue);
-            }
-            doTest(bos.toByteArray());
-        }
-    }
-
-    public void testRepetitionsIThreads() throws Exception {
-        final Random r = random();
-        int threadCount = TestUtil.nextInt(r, 2, 6);
-        Thread[] threads = new Thread[threadCount];
-        final CountDownLatch startingGun = new CountDownLatch(1);
-        for (int tid = 0; tid < threadCount; tid++) {
-            final long seed = r.nextLong();
-            threads[tid] = new Thread() {
-                @Override
-                public void run() {
-                    try {
-                        Random r = new Random(seed);
-                        startingGun.await();
-                        for (int i = 0; i < 10; i++) {
-                            int numInts = TestUtil.nextInt(r, 1, 20000);
-                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                            int theValue = r.nextInt();
-                            for (int j = 0; j < numInts; j++) {
-                                if (r.nextInt(10) == 0) {
-                                    theValue = r.nextInt();
-                                }
-                                bos.write((byte) (theValue >>> 24));
-                                bos.write((byte) (theValue >>> 16));
-                                bos.write((byte) (theValue >>> 8));
-                                bos.write((byte) theValue);
-                            }
-                            doTest(bos.toByteArray());
-                        }
-                    } catch (Exception e) {
-                        throw new RuntimeException(e);
-                    }
-                }
-            };
-            threads[tid].start();
-        }
-        startingGun.countDown();
-        for (Thread t : threads) {
-            t.join();
-        }
-    }
-
-    public void testRepetitionsS() throws IOException {
-        Random r = random();
-        for (int i = 0; i < 10; i++) {
-            int numShorts = TestUtil.nextInt(r, 1, 40000);
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-            short theValue = (short) r.nextInt(65535);
-            for (int j = 0; j < numShorts; j++) {
-                if (r.nextInt(10) == 0) {
-                    theValue = (short) r.nextInt(65535);
-                }
-                bos.write((byte) (theValue >>> 8));
-                bos.write((byte) theValue);
-            }
-            doTest(bos.toByteArray());
-        }
-    }
-
-    public void testMixed() throws IOException {
-        Random r = random();
-        LineFileDocs lineFileDocs = new LineFileDocs(r);
-        for (int i = 0; i < 2; ++i) {
-            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-            int prevInt = r.nextInt();
-            long prevLong = r.nextLong();
-            while (bos.size() < 400000) {
-                switch (r.nextInt(4)) {
-                    case 0:
-                        addInt(r, prevInt, bos);
-                        break;
-                    case 1:
-                        addLong(r, prevLong, bos);
-                        break;
-                    case 2:
-                        addString(lineFileDocs, bos);
-                        break;
-                    case 3:
-                        addBytes(r, bos);
-                        break;
-                    default:
-                        throw new IllegalStateException("Random is broken");
-                }
-            }
-            doTest(bos.toByteArray());
-        }
-    }
-
-    private void addLong(Random r, long prev, ByteArrayOutputStream bos) {
-        long theValue = prev;
-        if (r.nextInt(10) != 0) {
-            theValue = r.nextLong();
-        }
-        bos.write((byte) (theValue >>> 56));
-        bos.write((byte) (theValue >>> 48));
-        bos.write((byte) (theValue >>> 40));
-        bos.write((byte) (theValue >>> 32));
-        bos.write((byte) (theValue >>> 24));
-        bos.write((byte) (theValue >>> 16));
-        bos.write((byte) (theValue >>> 8));
-        bos.write((byte) theValue);
-    }
-
-    private void addInt(Random r, int prev, ByteArrayOutputStream bos) {
-        int theValue = prev;
-        if (r.nextInt(10) != 0) {
-            theValue = r.nextInt();
-        }
-        bos.write((byte) (theValue >>> 24));
-        bos.write((byte) (theValue >>> 16));
-        bos.write((byte) (theValue >>> 8));
-        bos.write((byte) theValue);
-    }
-
-    private void addString(LineFileDocs lineFileDocs, ByteArrayOutputStream bos) throws IOException {
-        String s = lineFileDocs.nextDoc().get("body");
-        bos.write(s.getBytes(StandardCharsets.UTF_8));
-    }
-
-    private void addBytes(Random r, ByteArrayOutputStream bos) throws IOException {
-        byte bytes[] = new byte[TestUtil.nextInt(r, 1, 10000)];
-        r.nextBytes(bytes);
-        bos.write(bytes);
-    }
-
-    public void testRepetitionsSThreads() throws Exception {
-        final Random r = random();
-        int threadCount = TestUtil.nextInt(r, 2, 6);
-        Thread[] threads = new Thread[threadCount];
-        final CountDownLatch startingGun = new CountDownLatch(1);
-        for (int tid = 0; tid < threadCount; tid++) {
-            final long seed = r.nextLong();
-            threads[tid] = new Thread() {
-                @Override
-                public void run() {
-                    try {
-                        Random r = new Random(seed);
-                        startingGun.await();
-                        for (int i = 0; i < 10; i++) {
-                            int numShorts = TestUtil.nextInt(r, 1, 40000);
-                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                            short theValue = (short) r.nextInt(65535);
-                            for (int j = 0; j < numShorts; j++) {
-                                if (r.nextInt(10) == 0) {
-                                    theValue = (short) r.nextInt(65535);
-                                }
-                                bos.write((byte) (theValue >>> 8));
-                                bos.write((byte) theValue);
-                            }
-                            doTest(bos.toByteArray());
-                        }
-                    } catch (Exception e) {
-                        throw new RuntimeException(e);
-                    }
-                }
-            };
-            threads[tid].start();
-        }
-        startingGun.countDown();
-        for (Thread t : threads) {
-            t.join();
-        }
-    }
-
-    private void doTest(byte bytes[]) throws IOException {
-        InputStream rawIn = new ByteArrayInputStream(bytes);
-        Compressor c = compressor;
-
-        ByteArrayOutputStream bos = new ByteArrayOutputStream();
-        final Random r = random();
-        int bufferSize = r.nextBoolean() ? 65535 : TestUtil.nextInt(random(), 1, 70000);
-        int prepadding = r.nextInt(70000);
-        int postpadding = r.nextInt(70000);
-        byte[] buffer = new byte[prepadding + bufferSize + postpadding];
-        int len;
-        try (OutputStream os = c.threadLocalOutputStream(bos)) {
-            r.nextBytes(buffer); // fill block completely with junk
-            while ((len = rawIn.read(buffer, prepadding, bufferSize)) != -1) {
-                os.write(buffer, prepadding, len);
-            }
-        }
-        rawIn.close();
-
-        // now we have compressed byte array
-        InputStream in = c.threadLocalInputStream(new ByteArrayInputStream(bos.toByteArray()));
-
-        // randomize constants again
-        bufferSize = r.nextBoolean() ? 65535 : TestUtil.nextInt(random(), 1, 70000);
-        prepadding = r.nextInt(70000);
-        postpadding = r.nextInt(70000);
-        buffer = new byte[prepadding + bufferSize + postpadding];
-        r.nextBytes(buffer); // fill block completely with junk
-
-        ByteArrayOutputStream uncompressedOut = new ByteArrayOutputStream();
-        while ((len = in.read(buffer, prepadding, bufferSize)) != -1) {
-            uncompressedOut.write(buffer, prepadding, len);
-        }
-        uncompressedOut.close();
-
-        assertArrayEquals(bytes, uncompressedOut.toByteArray());
+    @Override
+    protected Compressor compressor() {
+        return compressor;
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/compress/DeflateCompressedXContentTests.java b/server/src/test/java/org/opensearch/common/compress/DeflateCompressedXContentTests.java
index a14fabc30050d..5c9353d15e24a 100644
--- a/server/src/test/java/org/opensearch/common/compress/DeflateCompressedXContentTests.java
+++ b/server/src/test/java/org/opensearch/common/compress/DeflateCompressedXContentTests.java
@@ -33,8 +33,9 @@
 package org.opensearch.common.compress;
 
 import org.apache.lucene.tests.util.TestUtil;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.Compressor;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Assert;
 
diff --git a/server/src/test/java/org/opensearch/common/concurrent/AutoCloseableRefCountedTests.java b/server/src/test/java/org/opensearch/common/concurrent/AutoCloseableRefCountedTests.java
new file mode 100644
index 0000000000000..30ed6781d7bfb
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/concurrent/AutoCloseableRefCountedTests.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common.concurrent;
+
+import org.opensearch.common.util.concurrent.RefCounted;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import static org.mockito.Mockito.atMostOnce;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+public class AutoCloseableRefCountedTests extends OpenSearchTestCase {
+
+    private RefCounted mockRefCounted;
+    private AutoCloseableRefCounted<RefCounted> testObject;
+
+    @Before
+    public void setup() {
+        mockRefCounted = mock(RefCounted.class);
+        testObject = new AutoCloseableRefCounted<>(mockRefCounted);
+    }
+
+    public void testGet() {
+        assertEquals(mockRefCounted, testObject.get());
+    }
+
+    public void testClose() {
+        testObject.close();
+        verify(mockRefCounted, atMostOnce()).decRef();
+    }
+
+    public void testIdempotent() {
+        testObject.close();
+        testObject.close();
+        verify(mockRefCounted, atMostOnce()).decRef();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/concurrent/GatedAutoCloseableTests.java b/server/src/test/java/org/opensearch/common/concurrent/GatedAutoCloseableTests.java
deleted file mode 100644
index 63058da8f163a..0000000000000
--- a/server/src/test/java/org/opensearch/common/concurrent/GatedAutoCloseableTests.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.concurrent;
-
-import org.junit.Before;
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.util.concurrent.atomic.AtomicInteger;
-
-public class GatedAutoCloseableTests extends OpenSearchTestCase {
-
-    private AtomicInteger testRef;
-    private GatedAutoCloseable<AtomicInteger> testObject;
-
-    @Before
-    public void setup() {
-        testRef = new AtomicInteger(0);
-        testObject = new GatedAutoCloseable<>(testRef, testRef::incrementAndGet);
-    }
-
-    public void testGet() {
-        assertEquals(0, testObject.get().get());
-    }
-
-    public void testClose() {
-        testObject.close();
-        assertEquals(1, testObject.get().get());
-    }
-
-    public void testIdempotent() {
-        testObject.close();
-        testObject.close();
-        assertEquals(1, testObject.get().get());
-    }
-}
diff --git a/server/src/test/java/org/opensearch/common/concurrent/GatedCloseableTests.java b/server/src/test/java/org/opensearch/common/concurrent/GatedCloseableTests.java
index 0645f971b8d63..c8cabf391abfa 100644
--- a/server/src/test/java/org/opensearch/common/concurrent/GatedCloseableTests.java
+++ b/server/src/test/java/org/opensearch/common/concurrent/GatedCloseableTests.java
@@ -13,8 +13,8 @@
 
 package org.opensearch.common.concurrent;
 
-import org.junit.Before;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.nio.file.FileSystem;
diff --git a/server/src/test/java/org/opensearch/common/concurrent/OneWayGateTests.java b/server/src/test/java/org/opensearch/common/concurrent/OneWayGateTests.java
index 357bf3ae321f8..87f6600a57483 100644
--- a/server/src/test/java/org/opensearch/common/concurrent/OneWayGateTests.java
+++ b/server/src/test/java/org/opensearch/common/concurrent/OneWayGateTests.java
@@ -13,8 +13,8 @@
 
 package org.opensearch.common.concurrent;
 
-import org.junit.Before;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 public class OneWayGateTests extends OpenSearchTestCase {
 
diff --git a/server/src/test/java/org/opensearch/common/concurrent/RefCountedReleasableTests.java b/server/src/test/java/org/opensearch/common/concurrent/RefCountedReleasableTests.java
index 63c0873f1593d..d32cfbdf3b7b6 100644
--- a/server/src/test/java/org/opensearch/common/concurrent/RefCountedReleasableTests.java
+++ b/server/src/test/java/org/opensearch/common/concurrent/RefCountedReleasableTests.java
@@ -13,8 +13,8 @@
 
 package org.opensearch.common.concurrent;
 
-import org.junit.Before;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
diff --git a/server/src/test/java/org/opensearch/common/geo/BaseGeoParsingTestCase.java b/server/src/test/java/org/opensearch/common/geo/BaseGeoParsingTestCase.java
index f718d47dc17d2..2c8b8e6d9f964 100644
--- a/server/src/test/java/org/opensearch/common/geo/BaseGeoParsingTestCase.java
+++ b/server/src/test/java/org/opensearch/common/geo/BaseGeoParsingTestCase.java
@@ -32,17 +32,12 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.utils.GeographyValidator;
 import org.opensearch.index.mapper.GeoShapeIndexer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.hamcrest.OpenSearchGeoAssertions;
-import org.locationtech.jts.geom.Geometry;
-import org.locationtech.jts.geom.GeometryFactory;
-import org.locationtech.spatial4j.shape.Shape;
-import org.locationtech.spatial4j.shape.ShapeCollection;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 
 import java.io.IOException;
 import java.text.ParseException;
@@ -50,6 +45,12 @@
 import java.util.Arrays;
 import java.util.List;
 
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.spatial4j.shape.Shape;
+import org.locationtech.spatial4j.shape.ShapeCollection;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
 import static org.opensearch.common.geo.builders.ShapeBuilder.SPATIAL_CONTEXT;
 
 /** Base class for all geo parsing tests */
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoBoundingBoxTests.java b/server/src/test/java/org/opensearch/common/geo/GeoBoundingBoxTests.java
index a82d1939d8ea4..34451ca407163 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoBoundingBoxTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoBoundingBoxTests.java
@@ -34,9 +34,9 @@
 
 import org.apache.lucene.geo.GeoEncodingUtils;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geo.GeometryTestUtils;
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoDistanceTests.java b/server/src/test/java/org/opensearch/common/geo/GeoDistanceTests.java
index 033f02f9a8f7d..0fad75d556be6 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoDistanceTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoDistanceTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.DistanceUnit;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoJsonParserTests.java b/server/src/test/java/org/opensearch/common/geo/GeoJsonParserTests.java
index 2203a50dc19c4..c7a4a9e4865b7 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoJsonParserTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoJsonParserTests.java
@@ -32,12 +32,11 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Circle;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
@@ -479,85 +478,84 @@ public void testParseInvalidMultipoint() throws IOException {
 
     public void testParseInvalidDimensionalMultiPolygon() throws IOException {
         // test invalid multipolygon (an "accidental" polygon with inner rings outside outer ring)
-        String multiPolygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "MultiPolygon")
-                .startArray("coordinates")
-                .startArray()// first poly (without holes)
-                .startArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .startArray()// second poly (with hole)
-                .startArray()
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .endArray()
-                .startArray()// hole
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.2)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.2)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String multiPolygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "MultiPolygon")
+            .startArray("coordinates")
+            .startArray()// first poly (without holes)
+            .startArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .startArray()// second poly (with hole)
+            .startArray()
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .endArray()
+            .startArray()// hole
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.2)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.2)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, multiPolygonGeoJson)) {
             parser.nextToken();
@@ -572,24 +570,23 @@ public void testParseInvalidPolygon() throws IOException {
          * per the GeoJSON specification
          */
         // test case 1: create an invalid polygon with only 2 points
-        String invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .startArray()
-                .value(-75.022)
-                .value(41.783)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .startArray()
+            .value(-75.022)
+            .value(41.783)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
             expectThrows(XContentParseException.class, () -> new GeoJson(true, false, new GeographyValidator(false)).fromXContent(parser));
@@ -597,20 +594,19 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 2: create an invalid polygon with only 1 point
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -619,18 +615,17 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 3: create an invalid polygon with 0 points
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -639,20 +634,19 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 4: create an invalid polygon with null value points
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .nullValue()
-                .nullValue()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .nullValue()
+            .nullValue()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -661,16 +655,15 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 5: create an invalid polygon with 1 invalid LinearRing
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .nullValue()
-                .nullValue()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .nullValue()
+            .nullValue()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -679,9 +672,13 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 6: create an invalid polygon with 0 LinearRings
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().field("type", "polygon").startArray("coordinates").endArray().endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -690,18 +687,17 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 7: create an invalid polygon with 0 LinearRings
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoJsonSerializationTests.java b/server/src/test/java/org/opensearch/common/geo/GeoJsonSerializationTests.java
index 2b943a65ef4d8..480d8dba8f78f 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoJsonSerializationTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoJsonSerializationTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.common.geo;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geo.GeometryTestUtils;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.utils.GeographyValidator;
@@ -102,7 +102,9 @@ private void xContentTest(Supplier<Geometry> instanceSupplier) throws IOExceptio
         AbstractXContentTestCase.xContentTester(
             this::createParser,
             () -> new GeometryWrapper(instanceSupplier.get()),
-            (geometryWrapper, xContentBuilder) -> { geometryWrapper.toXContent(xContentBuilder, ToXContent.EMPTY_PARAMS); },
+            (geometryWrapper, xContentBuilder) -> {
+                geometryWrapper.toXContent(xContentBuilder, ToXContent.EMPTY_PARAMS);
+            },
             GeometryWrapper::fromXContent
         ).supportsUnknownFields(true).test();
     }
@@ -151,7 +153,7 @@ public void testToMap() throws IOException {
             StreamInput input = BytesReference.bytes(builder).streamInput();
 
             try (
-                XContentParser parser = XContentType.JSON.xContent()
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, input)
             ) {
                 Map<String, Object> map = GeoJson.toMap(geometry);
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoJsonShapeParserTests.java b/server/src/test/java/org/opensearch/common/geo/GeoJsonShapeParserTests.java
index 2ca692a8db374..55ce961f90380 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoJsonShapeParserTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoJsonShapeParserTests.java
@@ -35,14 +35,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.geo.parsers.ShapeParser;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
 import org.opensearch.geometry.Line;
@@ -54,6 +53,14 @@
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.hamcrest.OpenSearchGeoAssertions;
+
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.LineString;
 import org.locationtech.jts.geom.LinearRing;
@@ -68,13 +75,6 @@
 import org.locationtech.spatial4j.shape.ShapeCollection;
 import org.locationtech.spatial4j.shape.jts.JtsPoint;
 
-import java.io.IOException;
-import java.text.ParseException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import static org.opensearch.common.geo.builders.ShapeBuilder.SPATIAL_CONTEXT;
 
 /**
@@ -553,82 +553,81 @@ public void testParseInvalidMultipoint() throws IOException {
 
     public void testParseInvalidMultiPolygon() throws IOException {
         // test invalid multipolygon (an "accidental" polygon with inner rings outside outer ring)
-        String multiPolygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "MultiPolygon")
-                .startArray("coordinates")
-                .startArray()// one poly (with two holes)
-                .startArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .endArray()
-                .startArray()// first hole
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .endArray()
-                .startArray()// second hole
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.2)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.2)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String multiPolygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "MultiPolygon")
+            .startArray("coordinates")
+            .startArray()// one poly (with two holes)
+            .startArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .endArray()
+            .startArray()// first hole
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .endArray()
+            .startArray()// second hole
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.2)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.2)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, multiPolygonGeoJson)) {
             parser.nextToken();
@@ -639,85 +638,84 @@ public void testParseInvalidMultiPolygon() throws IOException {
 
     public void testParseInvalidDimensionalMultiPolygon() throws IOException {
         // test invalid multipolygon (an "accidental" polygon with inner rings outside outer ring)
-        String multiPolygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "MultiPolygon")
-                .startArray("coordinates")
-                .startArray()// first poly (without holes)
-                .startArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(2.0)
-                .endArray()
-                .startArray()
-                .value(103.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(3.0)
-                .endArray()
-                .startArray()
-                .value(102.0)
-                .value(2.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .startArray()// second poly (with hole)
-                .startArray()
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(101.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(1.0)
-                .endArray()
-                .startArray()
-                .value(100.0)
-                .value(0.0)
-                .endArray()
-                .endArray()
-                .startArray()// hole
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.2)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.2)
-                .endArray()
-                .startArray()
-                .value(100.8)
-                .value(0.8)
-                .endArray()
-                .startArray()
-                .value(100.2)
-                .value(0.8)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String multiPolygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "MultiPolygon")
+            .startArray("coordinates")
+            .startArray()// first poly (without holes)
+            .startArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(2.0)
+            .endArray()
+            .startArray()
+            .value(103.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(3.0)
+            .endArray()
+            .startArray()
+            .value(102.0)
+            .value(2.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .startArray()// second poly (with hole)
+            .startArray()
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(101.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(1.0)
+            .endArray()
+            .startArray()
+            .value(100.0)
+            .value(0.0)
+            .endArray()
+            .endArray()
+            .startArray()// hole
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.2)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.2)
+            .endArray()
+            .startArray()
+            .value(100.8)
+            .value(0.8)
+            .endArray()
+            .startArray()
+            .value(100.2)
+            .value(0.8)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, multiPolygonGeoJson)) {
             parser.nextToken();
@@ -728,40 +726,39 @@ public void testParseInvalidDimensionalMultiPolygon() throws IOException {
 
     public void testParseOGCPolygonWithoutHoles() throws IOException, ParseException {
         // test 1: ccw poly not crossing dateline
-        String polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -775,40 +772,39 @@ public void testParseOGCPolygonWithoutHoles() throws IOException, ParseException
         }
 
         // test 2: ccw poly crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -822,154 +818,151 @@ public void testParseOGCPolygonWithoutHoles() throws IOException, ParseException
         }
 
         // test 3: cw poly not crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(180.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(180.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
-
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
-            parser.nextToken();
-            Shape shape = ShapeParser.parse(parser).buildS4J();
-            OpenSearchGeoAssertions.assertPolygon(shape, true);
-        }
-
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
-            parser.nextToken();
-            OpenSearchGeoAssertions.assertPolygon(parse(parser), false);
-        }
-
-        // test 4: cw poly crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(184.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(184.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(174.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
-
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
-            parser.nextToken();
-            Shape shape = ShapeParser.parse(parser).buildS4J();
-            OpenSearchGeoAssertions.assertMultiPolygon(shape, true);
-        }
-
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
-            parser.nextToken();
-            OpenSearchGeoAssertions.assertMultiPolygon(parse(parser), false);
-        }
-    }
-
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(180.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(180.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
+
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
+            parser.nextToken();
+            Shape shape = ShapeParser.parse(parser).buildS4J();
+            OpenSearchGeoAssertions.assertPolygon(shape, true);
+        }
+
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
+            parser.nextToken();
+            OpenSearchGeoAssertions.assertPolygon(parse(parser), false);
+        }
+
+        // test 4: cw poly crossing dateline
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(184.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(184.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(174.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
+
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
+            parser.nextToken();
+            Shape shape = ShapeParser.parse(parser).buildS4J();
+            OpenSearchGeoAssertions.assertMultiPolygon(shape, true);
+        }
+
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
+            parser.nextToken();
+            OpenSearchGeoAssertions.assertMultiPolygon(parse(parser), false);
+        }
+    }
+
     public void testParseOGCPolygonWithHoles() throws IOException, ParseException {
         // test 1: ccw poly not crossing dateline
-        String polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .startArray()
-                .startArray()
-                .value(-172.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(174.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-172.0)
-                .value(-8.0)
-                .endArray()
-                .startArray()
-                .value(-172.0)
-                .value(8.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .startArray()
+            .startArray()
+            .value(-172.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(174.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-172.0)
+            .value(-8.0)
+            .endArray()
+            .startArray()
+            .value(-172.0)
+            .value(8.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -983,58 +976,57 @@ public void testParseOGCPolygonWithHoles() throws IOException, ParseException {
         }
 
         // test 2: ccw poly crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .endArray()
-                .startArray()
-                .startArray()
-                .value(178.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(-178.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(-180.0)
-                .value(-8.0)
-                .endArray()
-                .startArray()
-                .value(178.0)
-                .value(8.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .endArray()
+            .startArray()
+            .startArray()
+            .value(178.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(-178.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(-180.0)
+            .value(-8.0)
+            .endArray()
+            .startArray()
+            .value(178.0)
+            .value(8.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -1048,58 +1040,57 @@ public void testParseOGCPolygonWithHoles() throws IOException, ParseException {
         }
 
         // test 3: cw poly not crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(180.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(179.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .startArray()
-                .startArray()
-                .value(177.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(179.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(179.0)
-                .value(-8.0)
-                .endArray()
-                .startArray()
-                .value(177.0)
-                .value(8.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(180.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(179.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .startArray()
+            .startArray()
+            .value(177.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(179.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(179.0)
+            .value(-8.0)
+            .endArray()
+            .startArray()
+            .value(177.0)
+            .value(8.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -1113,58 +1104,57 @@ public void testParseOGCPolygonWithHoles() throws IOException, ParseException {
         }
 
         // test 4: cw poly crossing dateline
-        polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(183.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(183.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(183.0)
-                .value(10.0)
-                .endArray()
-                .endArray()
-                .startArray()
-                .startArray()
-                .value(178.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(182.0)
-                .value(8.0)
-                .endArray()
-                .startArray()
-                .value(180.0)
-                .value(-8.0)
-                .endArray()
-                .startArray()
-                .value(178.0)
-                .value(8.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(183.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(183.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(183.0)
+            .value(10.0)
+            .endArray()
+            .endArray()
+            .startArray()
+            .startArray()
+            .value(178.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(182.0)
+            .value(8.0)
+            .endArray()
+            .startArray()
+            .value(180.0)
+            .value(-8.0)
+            .endArray()
+            .startArray()
+            .value(178.0)
+            .value(8.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
@@ -1184,24 +1174,23 @@ public void testParseInvalidPolygon() throws IOException {
          * per the GeoJSON specification
          */
         // test case 1: create an invalid polygon with only 2 points
-        String invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .startArray()
-                .value(-75.022)
-                .value(41.783)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .startArray()
+            .value(-75.022)
+            .value(41.783)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
             OpenSearchGeoAssertions.assertValidException(parser, OpenSearchParseException.class);
@@ -1209,20 +1198,19 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 2: create an invalid polygon with only 1 point
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1231,18 +1219,17 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 3: create an invalid polygon with 0 points
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1251,20 +1238,19 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 4: create an invalid polygon with null value points
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .nullValue()
-                .nullValue()
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .nullValue()
+            .nullValue()
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1273,16 +1259,15 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 5: create an invalid polygon with 1 invalid LinearRing
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .nullValue()
-                .nullValue()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .nullValue()
+            .nullValue()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1291,9 +1276,13 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 6: create an invalid polygon with 0 LinearRings
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().field("type", "polygon").startArray("coordinates").endArray().endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1302,18 +1291,17 @@ public void testParseInvalidPolygon() throws IOException {
         }
 
         // test case 7: create an invalid polygon with 0 LinearRings
-        invalidPoly = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "polygon")
-                .startArray("coordinates")
-                .startArray()
-                .value(-74.011)
-                .value(40.753)
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        invalidPoly = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "polygon")
+            .startArray("coordinates")
+            .startArray()
+            .value(-74.011)
+            .value(40.753)
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, invalidPoly)) {
             parser.nextToken();
@@ -1408,44 +1396,43 @@ public void testParsePolygonWithHole() throws IOException, ParseException {
 
     public void testParseSelfCrossingPolygon() throws IOException {
         // test self crossing ccw poly not crossing dateline
-        String polygonGeoJson = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .field("type", "Polygon")
-                .startArray("coordinates")
-                .startArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(10.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(-10.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(-15.0)
-                .endArray()
-                .startArray()
-                .value(-177.0)
-                .value(15.0)
-                .endArray()
-                .startArray()
-                .value(172.0)
-                .value(0.0)
-                .endArray()
-                .startArray()
-                .value(176.0)
-                .value(15.0)
-                .endArray()
-                .endArray()
-                .endArray()
-                .endObject()
-        );
+        String polygonGeoJson = XContentFactory.jsonBuilder()
+            .startObject()
+            .field("type", "Polygon")
+            .startArray("coordinates")
+            .startArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(10.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(-10.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(-15.0)
+            .endArray()
+            .startArray()
+            .value(-177.0)
+            .value(15.0)
+            .endArray()
+            .startArray()
+            .value(172.0)
+            .value(0.0)
+            .endArray()
+            .startArray()
+            .value(176.0)
+            .value(15.0)
+            .endArray()
+            .endArray()
+            .endArray()
+            .endObject()
+            .toString();
 
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, polygonGeoJson)) {
             parser.nextToken();
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoUtilTests.java b/server/src/test/java/org/opensearch/common/geo/GeoUtilTests.java
index fc3e8c4c2ec84..9768b4ede7277 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoUtilTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoUtilTests.java
@@ -32,10 +32,10 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/geo/GeoWKTShapeParserTests.java b/server/src/test/java/org/opensearch/common/geo/GeoWKTShapeParserTests.java
index cd05331442be2..3da6d633bb125 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeoWKTShapeParserTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeoWKTShapeParserTests.java
@@ -50,9 +50,9 @@
 import org.opensearch.common.geo.parsers.GeoWKTParser;
 import org.opensearch.common.geo.parsers.ShapeParser;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
 import org.opensearch.geometry.Line;
@@ -64,6 +64,14 @@
 import org.opensearch.index.mapper.LegacyGeoShapeFieldMapper;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.test.geo.RandomShapeGenerator;
+
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.LineString;
 import org.locationtech.jts.geom.LinearRing;
@@ -76,13 +84,6 @@
 import org.locationtech.spatial4j.shape.ShapeCollection;
 import org.locationtech.spatial4j.shape.jts.JtsPoint;
 
-import java.io.IOException;
-import java.text.ParseException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import static org.opensearch.common.geo.builders.ShapeBuilder.SPATIAL_CONTEXT;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.hasToString;
diff --git a/server/src/test/java/org/opensearch/common/geo/GeometryIOTests.java b/server/src/test/java/org/opensearch/common/geo/GeometryIOTests.java
index d24a538f5dd16..698697b789a30 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeometryIOTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeometryIOTests.java
@@ -34,9 +34,9 @@
 
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
 import org.opensearch.geometry.ShapeType;
diff --git a/server/src/test/java/org/opensearch/common/geo/GeometryIndexerTests.java b/server/src/test/java/org/opensearch/common/geo/GeometryIndexerTests.java
index 116b91b568c47..297b7d9f65d5f 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeometryIndexerTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeometryIndexerTests.java
@@ -32,21 +32,10 @@
 
 package org.opensearch.common.geo;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.not;
-
-import java.io.IOException;
-import java.text.ParseException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geo.GeometryTestUtils;
 import org.opensearch.geometry.Circle;
 import org.opensearch.geometry.Geometry;
@@ -61,8 +50,20 @@
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.index.mapper.GeoShapeIndexer;
 import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
 import org.locationtech.spatial4j.exception.InvalidShapeException;
 
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.not;
+
 public class GeometryIndexerTests extends OpenSearchTestCase {
 
     GeoShapeIndexer indexer = new GeoShapeIndexer(true, "test");
diff --git a/server/src/test/java/org/opensearch/common/geo/GeometryParserTests.java b/server/src/test/java/org/opensearch/common/geo/GeometryParserTests.java
index 93f23d3a35ace..dded3739086aa 100644
--- a/server/src/test/java/org/opensearch/common/geo/GeometryParserTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/GeometryParserTests.java
@@ -33,12 +33,11 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.GeometryCollection;
 import org.opensearch.geometry.Line;
@@ -73,7 +72,7 @@ public void testGeoJsonParsing() throws Exception {
             assertEquals(new Point(100, 0), format.fromXContent(parser));
             XContentBuilder newGeoJson = XContentFactory.jsonBuilder();
             format.toXContent(new Point(100, 10), newGeoJson, ToXContent.EMPTY_PARAMS);
-            assertEquals("{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}", Strings.toString(newGeoJson));
+            assertEquals("{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}", newGeoJson.toString());
         }
 
         XContentBuilder pointGeoJsonWithZ = XContentFactory.jsonBuilder()
@@ -147,7 +146,7 @@ public void testWKTParsing() throws Exception {
             XContentBuilder newGeoJson = XContentFactory.jsonBuilder().startObject().field("val");
             format.toXContent(new Point(100, 10), newGeoJson, ToXContent.EMPTY_PARAMS);
             newGeoJson.endObject();
-            assertEquals("{\"val\":\"POINT (100.0 10.0)\"}", Strings.toString(newGeoJson));
+            assertEquals("{\"val\":\"POINT (100.0 10.0)\"}", newGeoJson.toString());
         }
 
         // Make sure we can parse values outside the normal lat lon boundaries
@@ -178,12 +177,12 @@ public void testNullParsing() throws Exception {
             // if we serialize non-null value - it should be serialized as geojson
             format.toXContent(new Point(100, 10), newGeoJson, ToXContent.EMPTY_PARAMS);
             newGeoJson.endObject();
-            assertEquals("{\"val\":{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}}", Strings.toString(newGeoJson));
+            assertEquals("{\"val\":{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}}", newGeoJson.toString());
 
             newGeoJson = XContentFactory.jsonBuilder().startObject().field("val");
             format.toXContent(null, newGeoJson, ToXContent.EMPTY_PARAMS);
             newGeoJson.endObject();
-            assertEquals("{\"val\":null}", Strings.toString(newGeoJson));
+            assertEquals("{\"val\":null}", newGeoJson.toString());
 
         }
     }
diff --git a/server/src/test/java/org/opensearch/common/geo/ShapeBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/ShapeBuilderTests.java
index ef87786b0b921..e98ac7e0dccc5 100644
--- a/server/src/test/java/org/opensearch/common/geo/ShapeBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/ShapeBuilderTests.java
@@ -43,6 +43,7 @@
 import org.opensearch.geometry.LinearRing;
 import org.opensearch.index.mapper.GeoShapeIndexer;
 import org.opensearch.test.OpenSearchTestCase;
+
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.LineString;
 import org.locationtech.jts.geom.Polygon;
diff --git a/server/src/test/java/org/opensearch/common/geo/ShapeRelationTests.java b/server/src/test/java/org/opensearch/common/geo/ShapeRelationTests.java
index d006d7d8fff28..42a4fe08b5273 100644
--- a/server/src/test/java/org/opensearch/common/geo/ShapeRelationTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/ShapeRelationTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/geo/SpatialStrategyTests.java b/server/src/test/java/org/opensearch/common/geo/SpatialStrategyTests.java
index 9860a593bc589..bfe1c7cea247f 100644
--- a/server/src/test/java/org/opensearch/common/geo/SpatialStrategyTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/SpatialStrategyTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.geo;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/AbstractShapeBuilderTestCase.java b/server/src/test/java/org/opensearch/common/geo/builders/AbstractShapeBuilderTestCase.java
index edae45ed0d439..72505a6c02ca5 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/AbstractShapeBuilderTestCase.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/AbstractShapeBuilderTestCase.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.common.geo.GeoShapeType;
 import org.opensearch.common.geo.parsers.ShapeParser;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -86,7 +86,7 @@ public static void afterClass() throws Exception {
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             SB testShape = createTestShapeBuilder();
-            XContentBuilder contentBuilder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder contentBuilder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 contentBuilder.prettyPrint();
             }
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/CircleBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/CircleBuilderTests.java
index 039164881e3e8..71a26db856798 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/CircleBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/CircleBuilderTests.java
@@ -33,10 +33,11 @@
 package org.opensearch.common.geo.builders;
 
 import org.opensearch.common.unit.DistanceUnit;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+
 public class CircleBuilderTests extends AbstractShapeBuilderTestCase<CircleBuilder> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/EnvelopeBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/EnvelopeBuilderTests.java
index 03f4a47fd2722..7ef1e6e6b9a46 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/EnvelopeBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/EnvelopeBuilderTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
-
 import org.opensearch.test.geo.RandomShapeGenerator;
-import org.locationtech.spatial4j.shape.Rectangle;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Rectangle;
+
 public class EnvelopeBuilderTests extends AbstractShapeBuilderTestCase<EnvelopeBuilder> {
 
     public void testInvalidConstructorArgs() {
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/LineStringBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/LineStringBuilderTests.java
index 316274c53b134..4e8b6b827842a 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/LineStringBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/LineStringBuilderTests.java
@@ -34,11 +34,12 @@
 
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.io.IOException;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 public class LineStringBuilderTests extends AbstractShapeBuilderTestCase<LineStringBuilder> {
 
     public void testInvalidConstructorArgs() {
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/MultiLineStringBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/MultiLineStringBuilderTests.java
index 63e7478403677..01f247a061faa 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/MultiLineStringBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/MultiLineStringBuilderTests.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+
 public class MultiLineStringBuilderTests extends AbstractShapeBuilderTestCase<MultiLineStringBuilder> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/MultiPointBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/MultiPointBuilderTests.java
index 87c41db53c1cf..90fdefa8ea128 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/MultiPointBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/MultiPointBuilderTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
-
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
 
 import java.io.IOException;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+
 public class MultiPointBuilderTests extends AbstractShapeBuilderTestCase<MultiPointBuilder> {
 
     public void testInvalidBuilderException() {
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/PointBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/PointBuilderTests.java
index cd74bb6adef15..d9dc010cb5675 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/PointBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/PointBuilderTests.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+
 public class PointBuilderTests extends AbstractShapeBuilderTestCase<PointBuilder> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/common/geo/builders/PolygonBuilderTests.java b/server/src/test/java/org/opensearch/common/geo/builders/PolygonBuilderTests.java
index 14af7fc29687f..db9cf815784a9 100644
--- a/server/src/test/java/org/opensearch/common/geo/builders/PolygonBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/geo/builders/PolygonBuilderTests.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.common.geo.builders;
 
-import org.locationtech.jts.geom.Coordinate;
 import org.opensearch.common.geo.builders.ShapeBuilder.Orientation;
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
-import org.locationtech.spatial4j.exception.InvalidShapeException;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.exception.InvalidShapeException;
+
 import static org.hamcrest.Matchers.equalTo;
 
 public class PolygonBuilderTests extends AbstractShapeBuilderTestCase<PolygonBuilder> {
diff --git a/server/src/test/java/org/opensearch/common/hppc/HppcMapsTests.java b/server/src/test/java/org/opensearch/common/hppc/HppcMapsTests.java
deleted file mode 100644
index de3c2cf909383..0000000000000
--- a/server/src/test/java/org/opensearch/common/hppc/HppcMapsTests.java
+++ /dev/null
@@ -1,111 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.common.hppc;
-
-import com.carrotsearch.hppc.ObjectHashSet;
-import org.opensearch.Assertions;
-import org.opensearch.common.collect.HppcMaps;
-import org.opensearch.test.OpenSearchTestCase;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.hamcrest.Matchers.equalTo;
-
-public class HppcMapsTests extends OpenSearchTestCase {
-    public void testIntersection() throws Exception {
-        assumeTrue("assertions enabled", Assertions.ENABLED);
-        ObjectHashSet<String> set1 = ObjectHashSet.from("1", "2", "3");
-        ObjectHashSet<String> set2 = ObjectHashSet.from("1", "2", "3");
-        List<String> values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(3));
-        assertThat(values.contains("1"), equalTo(true));
-        assertThat(values.contains("2"), equalTo(true));
-        assertThat(values.contains("3"), equalTo(true));
-
-        set1 = ObjectHashSet.from("1", "2", "3");
-        set2 = ObjectHashSet.from("3", "4", "5");
-        values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(1));
-        assertThat(values.get(0), equalTo("3"));
-
-        set1 = ObjectHashSet.from("1", "2", "3");
-        set2 = ObjectHashSet.from("4", "5", "6");
-        values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(0));
-
-        set1 = ObjectHashSet.from();
-        set2 = ObjectHashSet.from("3", "4", "5");
-        values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(0));
-
-        set1 = ObjectHashSet.from("1", "2", "3");
-        set2 = ObjectHashSet.from();
-        values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(0));
-
-        set1 = ObjectHashSet.from();
-        set2 = ObjectHashSet.from();
-        values = toList(HppcMaps.intersection(set1, set2));
-        assertThat(values.size(), equalTo(0));
-
-        set1 = null;
-        set2 = ObjectHashSet.from();
-        try {
-            toList(HppcMaps.intersection(set1, set2));
-            fail();
-        } catch (AssertionError e) {}
-
-        set1 = ObjectHashSet.from();
-        set2 = null;
-        try {
-            toList(HppcMaps.intersection(set1, set2));
-            fail();
-        } catch (AssertionError e) {}
-
-        set1 = null;
-        set2 = null;
-        try {
-            toList(HppcMaps.intersection(set1, set2));
-            fail();
-        } catch (AssertionError e) {}
-    }
-
-    private List<String> toList(Iterable<String> iterable) {
-        List<String> list = new ArrayList<>();
-        for (String s : iterable) {
-            list.add(s);
-        }
-        return list;
-    }
-
-}
diff --git a/server/src/test/java/org/opensearch/common/io/VersionedCodecStreamWrapperTests.java b/server/src/test/java/org/opensearch/common/io/VersionedCodecStreamWrapperTests.java
new file mode 100644
index 0000000000000..938337fc5146e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/io/VersionedCodecStreamWrapperTests.java
@@ -0,0 +1,141 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.io;
+
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.IndexFormatTooNewException;
+import org.apache.lucene.index.IndexFormatTooOldException;
+import org.apache.lucene.store.BufferedChecksumIndexInput;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Unit tests for {@link org.opensearch.common.io.VersionedCodecStreamWrapper}.
+ */
+public class VersionedCodecStreamWrapperTests extends OpenSearchTestCase {
+
+    private static final String CODEC = "dummycodec";
+    private static final int VERSION = 1;
+
+    IndexIOStreamHandler<DummyObject> ioStreamHandler;
+    VersionedCodecStreamWrapper<DummyObject> versionedCodecStreamWrapper;
+
+    @Before
+    public void setup() throws IOException {
+        ioStreamHandler = mock(IndexIOStreamHandler.class);
+        versionedCodecStreamWrapper = new VersionedCodecStreamWrapper(ioStreamHandler, VERSION, CODEC);
+    }
+
+    public void testReadStream() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        DummyObject readData = versionedCodecStreamWrapper.readStream(createHeaderFooterBytes(CODEC, VERSION, true, true));
+        assertEquals(readData, expectedObject);
+    }
+
+    public void testReadWithOldVersionThrowsException() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        assertThrows(
+            IndexFormatTooOldException.class,
+            () -> versionedCodecStreamWrapper.readStream(createHeaderFooterBytes(CODEC, 0, true, true))
+        );
+    }
+
+    public void testReadWithNewVersionThrowsException() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        assertThrows(
+            IndexFormatTooNewException.class,
+            () -> versionedCodecStreamWrapper.readStream(createHeaderFooterBytes(CODEC, 2, true, true))
+        );
+    }
+
+    public void testReadWithUnexpectedCodecThrowsException() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        assertThrows(
+            CorruptIndexException.class,
+            () -> versionedCodecStreamWrapper.readStream(createHeaderFooterBytes("wrong codec", VERSION, true, true))
+        );
+    }
+
+    public void testReadWithNoHeaderThrowsException() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        assertThrows(
+            CorruptIndexException.class,
+            () -> versionedCodecStreamWrapper.readStream(createHeaderFooterBytes("wrong codec", VERSION, false, true))
+        );
+    }
+
+    public void testReadWithNoFooterThrowsException() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        when(ioStreamHandler.readContent(any())).thenReturn(expectedObject);
+        assertThrows(
+            CorruptIndexException.class,
+            () -> versionedCodecStreamWrapper.readStream(createHeaderFooterBytes("wrong codec", VERSION, true, false))
+        );
+    }
+
+    public void testWriteStream() throws IOException {
+        DummyObject expectedObject = new DummyObject("test read");
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        doAnswer(invocation -> {
+            IndexOutput io = invocation.getArgument(0);
+            io.writeString("test write");
+            return null;
+        }).when(ioStreamHandler).writeContent(indexOutput, expectedObject);
+        versionedCodecStreamWrapper.writeStream(indexOutput, expectedObject);
+        indexOutput.close();
+        IndexInput indexInput = new ByteArrayIndexInput("dummy bytes", BytesReference.toBytes(output.bytes()));
+        BufferedChecksumIndexInput bii = new BufferedChecksumIndexInput(indexInput);
+
+        CodecUtil.checkHeader(bii, CODEC, VERSION, VERSION);
+        assertEquals(bii.readString(), "test write");
+        CodecUtil.checkFooter(bii);
+    }
+
+    private ByteArrayIndexInput createHeaderFooterBytes(String codec, int version, boolean writeHeader, boolean writeFooter)
+        throws IOException {
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        if (writeHeader) {
+            CodecUtil.writeHeader(indexOutput, codec, version);
+        }
+        if (writeFooter) {
+            CodecUtil.writeFooter(indexOutput);
+        }
+        indexOutput.close();
+        return new ByteArrayIndexInput("dummy bytes", BytesReference.toBytes(output.bytes()));
+    }
+
+    private static class DummyObject {
+        private static String dummyString;
+
+        public DummyObject(String dummy) {
+            dummyString = dummy;
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/io/stream/AbstractWriteableEnumTestCase.java b/server/src/test/java/org/opensearch/common/io/stream/AbstractWriteableEnumTestCase.java
index 2786c63e8b4a4..82c9a2dc2bb98 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/AbstractWriteableEnumTestCase.java
+++ b/server/src/test/java/org/opensearch/common/io/stream/AbstractWriteableEnumTestCase.java
@@ -32,6 +32,9 @@
 
 package org.opensearch.common.io.stream;
 
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/io/stream/BytesStreamsTests.java b/server/src/test/java/org/opensearch/common/io/stream/BytesStreamsTests.java
index 0ff3511f26f30..d408898d04f04 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/BytesStreamsTests.java
+++ b/server/src/test/java/org/opensearch/common/io/stream/BytesStreamsTests.java
@@ -35,13 +35,19 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Constants;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.geo.GeoPoint;
+import org.opensearch.common.joda.Joda;
 import org.opensearch.common.lucene.BytesRefs;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.script.JodaCompatibleZonedDateTime;
 import org.opensearch.test.OpenSearchTestCase;
 import org.joda.time.DateTime;
@@ -321,9 +327,9 @@ public void testSimpleStreams() throws Exception {
         out.writeOptionalBytesReference(new BytesArray("test"));
         out.writeOptionalDouble(null);
         out.writeOptionalDouble(1.2);
-        out.writeTimeZone(DateTimeZone.forID("CET"));
-        out.writeOptionalTimeZone(DateTimeZone.getDefault());
-        out.writeOptionalTimeZone(null);
+        Joda.writeTimeZone(out, DateTimeZone.forID("CET"));
+        Joda.writeOptionalTimeZone(out, DateTimeZone.getDefault());
+        Joda.writeOptionalTimeZone(out, null);
         out.writeGenericValue(new DateTime(123456, DateTimeZone.forID("America/Los_Angeles")));
         final byte[] bytes = BytesReference.toBytes(out.bytes());
         StreamInput in = StreamInput.wrap(BytesReference.toBytes(out.bytes()));
@@ -354,9 +360,9 @@ public void testSimpleStreams() throws Exception {
         assertThat(in.readOptionalBytesReference(), equalTo(new BytesArray("test")));
         assertNull(in.readOptionalDouble());
         assertThat(in.readOptionalDouble(), closeTo(1.2, 0.0001));
-        assertEquals(DateTimeZone.forID("CET"), in.readTimeZone());
-        assertEquals(DateTimeZone.getDefault(), in.readOptionalTimeZone());
-        assertNull(in.readOptionalTimeZone());
+        assertEquals(DateTimeZone.forID("CET"), Joda.readTimeZone(in));
+        assertEquals(DateTimeZone.getDefault(), Joda.readOptionalTimeZone(in));
+        assertNull(Joda.readOptionalTimeZone(in));
         Object dt = in.readGenericValue();
         assertThat(dt, instanceOf(JodaCompatibleZonedDateTime.class));
         JodaCompatibleZonedDateTime jdt = (JodaCompatibleZonedDateTime) dt;
@@ -534,38 +540,6 @@ public void testWriteMap() throws IOException {
         assertThat(expected, equalTo(loaded));
     }
 
-    public void testWriteImmutableMap() throws IOException {
-        final int size = randomIntBetween(0, 100);
-        final ImmutableOpenMap.Builder<String, String> expectedBuilder = ImmutableOpenMap.builder(randomIntBetween(0, 100));
-        for (int i = 0; i < size; ++i) {
-            expectedBuilder.put(randomAlphaOfLength(2), randomAlphaOfLength(5));
-        }
-
-        final ImmutableOpenMap<String, String> expected = expectedBuilder.build();
-        final BytesStreamOutput out = new BytesStreamOutput();
-        out.writeMap(expected, StreamOutput::writeString, StreamOutput::writeString);
-        final StreamInput in = StreamInput.wrap(BytesReference.toBytes(out.bytes()));
-        final ImmutableOpenMap<String, String> loaded = in.readImmutableMap(StreamInput::readString, StreamInput::readString);
-
-        assertThat(expected, equalTo(loaded));
-    }
-
-    public void testWriteImmutableMapOfWritable() throws IOException {
-        final int size = randomIntBetween(0, 100);
-        final ImmutableOpenMap.Builder<TestWriteable, TestWriteable> expectedBuilder = ImmutableOpenMap.builder(randomIntBetween(0, 100));
-        for (int i = 0; i < size; ++i) {
-            expectedBuilder.put(new TestWriteable(randomBoolean()), new TestWriteable(randomBoolean()));
-        }
-
-        final ImmutableOpenMap<TestWriteable, TestWriteable> expected = expectedBuilder.build();
-        final BytesStreamOutput out = new BytesStreamOutput();
-        out.writeMap(expected);
-        final StreamInput in = StreamInput.wrap(BytesReference.toBytes(out.bytes()));
-        final ImmutableOpenMap<TestWriteable, TestWriteable> loaded = in.readImmutableMap(TestWriteable::new, TestWriteable::new);
-
-        assertThat(expected, equalTo(loaded));
-    }
-
     public void testWriteMapOfLists() throws IOException {
         final int size = randomIntBetween(0, 5);
         final Map<String, List<String>> expected = new HashMap<>(size);
@@ -672,9 +646,9 @@ public void testReadWriteGeoPoint() throws IOException {
 
         try (BytesStreamOutput out = new BytesStreamOutput()) {
             GeoPoint geoPoint = new GeoPoint(randomDouble(), randomDouble());
-            out.writeGeoPoint(geoPoint);
+            geoPoint.writeTo(out);
             StreamInput wrap = out.bytes().streamInput();
-            GeoPoint point = wrap.readGeoPoint();
+            GeoPoint point = new GeoPoint(wrap);
             assertEquals(point, geoPoint);
         }
     }
@@ -963,7 +937,7 @@ public void testWriteCircularReferenceException() throws IOException {
 
         BytesStreamOutput prodOut = new BytesStreamOutput() {
             @Override
-            boolean failOnTooManyNestedExceptions(Throwable throwable) {
+            public boolean failOnTooManyNestedExceptions(Throwable throwable) {
                 assertThat(throwable, sameInstance(rootEx));
                 return true;
             }
diff --git a/server/src/test/java/org/opensearch/common/io/stream/DelayableWriteableTests.java b/server/src/test/java/org/opensearch/common/io/stream/DelayableWriteableTests.java
index 930aaafaad33e..2fa56c5bbf770 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/DelayableWriteableTests.java
+++ b/server/src/test/java/org/opensearch/common/io/stream/DelayableWriteableTests.java
@@ -32,15 +32,20 @@
 
 package org.opensearch.common.io.stream;
 
-import static java.util.Collections.singletonList;
-import static org.hamcrest.Matchers.equalTo;
-
-import java.io.IOException;
-
 import org.opensearch.Version;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
+import java.io.IOException;
+
+import static java.util.Collections.singletonList;
+import static org.hamcrest.Matchers.equalTo;
+
 public class DelayableWriteableTests extends OpenSearchTestCase {
     // NOTE: we don't use AbstractWireSerializingTestCase because we don't implement equals and hashCode.
     private static class Example implements NamedWriteable {
@@ -118,12 +123,12 @@ private static class SneakOtherSideVersionOnWire implements Writeable {
         }
 
         SneakOtherSideVersionOnWire(StreamInput in) throws IOException {
-            version = Version.readVersion(in);
+            version = in.readVersion();
         }
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            Version.writeVersion(out.getVersion(), out);
+            out.writeVersion(out.getVersion());
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutputTests.java b/server/src/test/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutputTests.java
index 20f202149b17d..92ed8fac5aae0 100644
--- a/server/src/test/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutputTests.java
+++ b/server/src/test/java/org/opensearch/common/io/stream/ReleasableBytesStreamOutputTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/joda/JavaJodaTimeDuellingTests.java b/server/src/test/java/org/opensearch/common/joda/JavaJodaTimeDuellingTests.java
index 30fcf4bb32989..94ddfd7e7f100 100644
--- a/server/src/test/java/org/opensearch/common/joda/JavaJodaTimeDuellingTests.java
+++ b/server/src/test/java/org/opensearch/common/joda/JavaJodaTimeDuellingTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.common.joda;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.common.time.DateMathParser;
@@ -43,7 +42,6 @@
 import org.joda.time.DateTimeZone;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.ISODateTimeFormat;
-import org.junit.BeforeClass;
 
 import java.time.ZoneId;
 import java.time.ZoneOffset;
@@ -62,18 +60,6 @@ protected boolean enableWarningsCheck() {
         return false;
     }
 
-    @BeforeClass
-    public static void checkJvmProperties() {
-        boolean runtimeJdk8 = JavaVersion.current().getVersion().get(0) == 8;
-        assert (runtimeJdk8 && ("SPI,JRE".equals(System.getProperty("java.locale.providers"))))
-            || (false == runtimeJdk8 && ("SPI,COMPAT".equals(System.getProperty("java.locale.providers"))))
-            : "`-Djava.locale.providers` needs to be set";
-        assumeFalse(
-            "won't work in jdk8 " + "because SPI mechanism is not looking at classpath - needs ISOCalendarDataProvider in jre's ext/libs",
-            runtimeJdk8
-        );
-    }
-
     public void testTimezoneParsing() {
         /** this testcase won't work in joda. See comment in {@link #testPartialTimeParsing()}
          *  assertSameDateAs("2016-11-30T+01", "strict_date_optional_time", "strict_date_optional_time");
@@ -906,14 +892,6 @@ private void assertSamePrinterOutput(
         String jodaTimeOut = jodaDateFormatter.formatJoda(jodaDate);
 
         assertThat(jodaDate.getMillis(), is(javaDate.toInstant().toEpochMilli()));
-
-        if (JavaVersion.current().getVersion().get(0) == 8
-            && javaTimeOut.endsWith(".0")
-            && (format.equals("epoch_second") || format.equals("epoch_millis"))) {
-            // java 8 has a bug in DateTimeFormatter usage when printing dates that rely on isSupportedBy for fields, which is
-            // what we use for epoch time. This change accounts for that bug. It should be removed when java 8 support is removed
-            jodaTimeOut += ".0";
-        }
         String message = String.format(
             Locale.ROOT,
             "expected string representation to be equal for format [%s]: joda [%s], java [%s]",
diff --git a/server/src/test/java/org/opensearch/common/logging/HeaderWarningTests.java b/server/src/test/java/org/opensearch/common/logging/HeaderWarningTests.java
index b1ff70104d2cc..f2f3b1be2d9a3 100644
--- a/server/src/test/java/org/opensearch/common/logging/HeaderWarningTests.java
+++ b/server/src/test/java/org/opensearch/common/logging/HeaderWarningTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.common.logging;
 
 import com.carrotsearch.randomizedtesting.generators.CodepointSetGenerator;
+
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/common/logging/RateLimitingFilterTests.java b/server/src/test/java/org/opensearch/common/logging/RateLimitingFilterTests.java
index be952712f261f..e95f47bef864c 100644
--- a/server/src/test/java/org/opensearch/common/logging/RateLimitingFilterTests.java
+++ b/server/src/test/java/org/opensearch/common/logging/RateLimitingFilterTests.java
@@ -38,8 +38,8 @@
 import org.junit.After;
 import org.junit.Before;
 
-import static org.apache.logging.log4j.core.Filter.Result;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.logging.log4j.core.Filter.Result;
 
 public class RateLimitingFilterTests extends OpenSearchTestCase {
 
diff --git a/server/src/test/java/org/opensearch/common/lucene/LuceneTests.java b/server/src/test/java/org/opensearch/common/lucene/LuceneTests.java
index 4c179309f16ba..4f4b31b1469de 100644
--- a/server/src/test/java/org/opensearch/common/lucene/LuceneTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/LuceneTests.java
@@ -31,25 +31,28 @@
 
 package org.opensearch.common.lucene;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.analysis.core.KeywordAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.document.LatLonDocValuesField;
+import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.IndexFormatTooOldException;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.NoDeletionPolicy;
 import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.SoftDeletesRetentionMergePolicy;
+import org.apache.lucene.index.StandardDirectoryReader;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
@@ -70,16 +73,22 @@
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.MMapDirectory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
+import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
+import org.opensearch.LegacyESVersion;
+import org.opensearch.Version;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.DoubleValuesComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.FloatValuesComparatorSource;
+import org.opensearch.index.fielddata.fieldcomparator.IntValuesComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.LongValuesComparatorSource;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.test.OpenSearchTestCase;
@@ -87,6 +96,7 @@
 
 import java.io.IOException;
 import java.io.StringReader;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
@@ -368,6 +378,37 @@ public void testNumDocs() throws IOException {
         dir.close();
     }
 
+    /**
+     * Tests whether old segments are readable and queryable based on the data documented
+     * in the README <a href="file:../../../../../resources/indices/bwc/es-6.3.0/README.md">here</a>.
+     */
+    public void testReadSegmentInfosExtendedCompatibility() throws IOException {
+        final String pathToTestIndex = "/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip";
+        final Version minVersion = LegacyESVersion.fromId(6000099);
+        Path tmp = createTempDir();
+        TestUtil.unzip(getClass().getResourceAsStream(pathToTestIndex), tmp);
+        try (MockDirectoryWrapper dir = newMockFSDirectory(tmp)) {
+            // The standard API will throw an exception
+            expectThrows(IndexFormatTooOldException.class, () -> Lucene.readSegmentInfos(dir));
+            SegmentInfos si = Lucene.readSegmentInfos(dir, minVersion);
+            assertEquals(1, Lucene.getNumDocs(si));
+            IndexCommit indexCommit = Lucene.getIndexCommit(si, dir);
+            // uses the "expert" Lucene API
+            try (
+                StandardDirectoryReader reader = (StandardDirectoryReader) DirectoryReader.open(
+                    indexCommit,
+                    minVersion.minimumIndexCompatibilityVersion().luceneVersion.major,
+                    null
+                )
+            ) {
+                IndexSearcher searcher = newSearcher(reader);
+                // radius too small, should get no results
+                assertFalse(Lucene.exists(searcher, LatLonPoint.newDistanceQuery("testLocation", 48.57532, -112.87695, 2)));
+                assertTrue(Lucene.exists(searcher, LatLonPoint.newDistanceQuery("testLocation", 48.57532, -112.87695, 20000)));
+            }
+        }
+    }
+
     public void testCount() throws Exception {
         Directory dir = newDirectory();
         RandomIndexWriter w = new RandomIndexWriter(random(), dir);
@@ -575,12 +616,13 @@ public void testWrapAllDocsLive() throws Exception {
         }
         try (DirectoryReader unwrapped = DirectoryReader.open(writer)) {
             DirectoryReader reader = Lucene.wrapAllDocsLive(unwrapped);
+            StoredFields storedFields = reader.storedFields();
             assertThat(reader.numDocs(), equalTo(liveDocs.size()));
             IndexSearcher searcher = new IndexSearcher(reader);
             Set<String> actualDocs = new HashSet<>();
             TopDocs topDocs = searcher.search(new MatchAllDocsQuery(), Integer.MAX_VALUE);
             for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
-                actualDocs.add(reader.document(scoreDoc.doc).get("id"));
+                actualDocs.add(storedFields.document(scoreDoc.doc).get("id"));
             }
             assertThat(actualDocs, equalTo(liveDocs));
         }
@@ -590,7 +632,8 @@ public void testWrapAllDocsLive() throws Exception {
     public void testWrapLiveDocsNotExposeAbortedDocuments() throws Exception {
         Directory dir = newDirectory();
         IndexWriterConfig config = newIndexWriterConfig().setSoftDeletesField(Lucene.SOFT_DELETES_FIELD)
-            .setMergePolicy(new SoftDeletesRetentionMergePolicy(Lucene.SOFT_DELETES_FIELD, MatchAllDocsQuery::new, newMergePolicy()));
+            .setMergePolicy(new SoftDeletesRetentionMergePolicy(Lucene.SOFT_DELETES_FIELD, MatchAllDocsQuery::new, newMergePolicy()))
+            .setMaxFullFlushMergeWaitMillis(0);
         IndexWriter writer = new IndexWriter(dir, config);
         int numDocs = between(1, 10);
         List<String> liveDocs = new ArrayList<>();
@@ -618,13 +661,14 @@ public void testWrapLiveDocsNotExposeAbortedDocuments() throws Exception {
         }
         try (DirectoryReader unwrapped = DirectoryReader.open(writer)) {
             DirectoryReader reader = Lucene.wrapAllDocsLive(unwrapped);
+            StoredFields storedFields = reader.storedFields();
             assertThat(reader.maxDoc(), equalTo(numDocs + abortedDocs));
             assertThat(reader.numDocs(), equalTo(liveDocs.size()));
             IndexSearcher searcher = new IndexSearcher(reader);
             List<String> actualDocs = new ArrayList<>();
             TopDocs topDocs = searcher.search(new MatchAllDocsQuery(), Integer.MAX_VALUE);
             for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
-                actualDocs.add(reader.document(scoreDoc.doc).get("id"));
+                actualDocs.add(storedFields.document(scoreDoc.doc).get("id"));
             }
             assertThat(actualDocs, equalTo(liveDocs));
         }
@@ -710,7 +754,7 @@ private static Tuple<SortField, SortField> randomSortFieldCustomComparatorSource
         IndexFieldData.XFieldComparatorSource comparatorSource;
         boolean reverse = randomBoolean();
         Object missingValue = null;
-        switch (randomIntBetween(0, 3)) {
+        switch (randomIntBetween(0, 4)) {
             case 0:
                 comparatorSource = new LongValuesComparatorSource(
                     null,
@@ -744,6 +788,15 @@ private static Tuple<SortField, SortField> randomSortFieldCustomComparatorSource
                 );
                 missingValue = comparatorSource.missingValue(reverse);
                 break;
+            case 4:
+                comparatorSource = new IntValuesComparatorSource(
+                    null,
+                    randomBoolean() ? randomInt() : null,
+                    randomFrom(MultiValueMode.values()),
+                    null
+                );
+                missingValue = comparatorSource.missingValue(reverse);
+                break;
             default:
                 throw new UnsupportedOperationException();
         }
diff --git a/server/src/test/java/org/opensearch/common/lucene/ShardCoreKeyMapTests.java b/server/src/test/java/org/opensearch/common/lucene/ShardCoreKeyMapTests.java
index 8abfb14fe3087..323ceeb95e157 100644
--- a/server/src/test/java/org/opensearch/common/lucene/ShardCoreKeyMapTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/ShardCoreKeyMapTests.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/lucene/index/FreqTermsEnumTests.java b/server/src/test/java/org/opensearch/common/lucene/index/FreqTermsEnumTests.java
index 025da248565fc..5dbbba570b758 100644
--- a/server/src/test/java/org/opensearch/common/lucene/index/FreqTermsEnumTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/index/FreqTermsEnumTests.java
@@ -43,14 +43,15 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
@@ -149,9 +150,10 @@ public void setUp() throws Exception {
 
         // now go over each doc, build the relevant references and filter
         reader = DirectoryReader.open(iw);
+        StoredFields storedFields = reader.storedFields();
         List<BytesRef> filterTerms = new ArrayList<>();
         for (int docId = 0; docId < reader.maxDoc(); docId++) {
-            Document doc = reader.document(docId);
+            Document doc = storedFields.document(docId);
             addFreqs(doc, referenceAll);
             if (!deletedIds.contains(doc.getField("id").stringValue())) {
                 addFreqs(doc, referenceNotDeleted);
diff --git a/server/src/test/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReaderTests.java b/server/src/test/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReaderTests.java
index 1a2e23d43b579..298eeb28fb2e9 100644
--- a/server/src/test/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReaderTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReaderTests.java
@@ -41,8 +41,8 @@
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.store.Directory;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 /** Simple tests for this filterreader */
diff --git a/server/src/test/java/org/opensearch/common/lucene/search/morelikethis/XMoreLikeThisTests.java b/server/src/test/java/org/opensearch/common/lucene/search/morelikethis/XMoreLikeThisTests.java
index e6a621037ef6d..b907d739a435b 100644
--- a/server/src/test/java/org/opensearch/common/lucene/search/morelikethis/XMoreLikeThisTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/search/morelikethis/XMoreLikeThisTests.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.common.lucene.search.morelikethis;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.mlt.MoreLikeThis;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.analysis.MockTokenizer;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/lucene/store/ByteArrayIndexInputTests.java b/server/src/test/java/org/opensearch/common/lucene/store/ByteArrayIndexInputTests.java
index bf331ca978009..827f9dd992294 100644
--- a/server/src/test/java/org/opensearch/common/lucene/store/ByteArrayIndexInputTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/store/ByteArrayIndexInputTests.java
@@ -32,8 +32,10 @@
 
 package org.opensearch.common.lucene.store;
 
+import java.io.EOFException;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 
 import static org.hamcrest.Matchers.containsString;
 
@@ -97,4 +99,58 @@ public void testSeekOverflow() throws IOException {
         }
     }
 
+    public void testRandomReadEdges() throws IOException {
+        final int size = 16;
+        byte[] input = Arrays.copyOfRange(randomUnicodeOfLength(size).getBytes(StandardCharsets.UTF_8), 0, size);
+        ByteArrayIndexInput indexInput = new ByteArrayIndexInput("test", input);
+        assertThrows(EOFException.class, () -> indexInput.readByte(-1));
+        assertThrows(EOFException.class, () -> indexInput.readShort(-1));
+        assertThrows(EOFException.class, () -> indexInput.readInt(-1));
+        assertThrows(EOFException.class, () -> indexInput.readLong(-1));
+        for (int i = 0; i < 10; i++) {
+            indexInput.readByte(size - Byte.BYTES);
+            indexInput.readShort(size - Short.BYTES);
+            indexInput.readInt(size - Integer.BYTES);
+            indexInput.readLong(size - Long.BYTES);
+            indexInput.readByte(0);
+            indexInput.readShort(0);
+            indexInput.readInt(0);
+            indexInput.readLong(0);
+        }
+        assertThrows(EOFException.class, () -> indexInput.readByte(size));
+        assertThrows(EOFException.class, () -> indexInput.readShort(size - Short.BYTES + 1));
+        assertThrows(EOFException.class, () -> indexInput.readInt(size - Integer.BYTES + 1));
+        assertThrows(EOFException.class, () -> indexInput.readLong(size - Long.BYTES + 1));
+    }
+
+    public void testRandomAccessReads() throws IOException {
+        byte[] bytes = {
+            (byte) 85,  // 01010101
+            (byte) 46,  // 00101110
+            (byte) 177, // 10110001
+            (byte) 36,  // 00100100
+            (byte) 231, // 11100111
+            (byte) 48,  // 00110000
+            (byte) 137, // 10001001
+            (byte) 37,  // 00100101
+            (byte) 137  // 10001001
+        };
+        ByteArrayIndexInput indexInput = new ByteArrayIndexInput("test", bytes);
+        // 00101110 01010101
+        assertEquals(11861, indexInput.readShort(0));
+        // 10110001 00101110
+        assertEquals(-20178, indexInput.readShort(1));
+        // 00100101 10001001
+        assertEquals(9609, indexInput.readShort(6));
+        // 00100100 10110001 00101110 01010101
+        assertEquals(615591509, indexInput.readInt(0));
+        // 00110000 11100111 00100100 10110001
+        assertEquals(820454577, indexInput.readInt(2));
+        // 00100101 10001001 00110000 11100111
+        assertEquals(629747943, indexInput.readInt(4));
+        // 00100101 10001001 00110000 11100111 00100100 10110001 00101110 01010101
+        assertEquals(2704746820523863637L, indexInput.readLong(0));
+        // 10001001 00100101 10001001 00110000 11100111 00100100 10110001 00101110
+        assertEquals(-8564288273245753042L, indexInput.readLong(1));
+    }
 }
diff --git a/server/src/test/java/org/opensearch/common/lucene/uid/VersionsTests.java b/server/src/test/java/org/opensearch/common/lucene/uid/VersionsTests.java
index 4c2a500bb5cd3..8eaf8f3a051dc 100644
--- a/server/src/test/java/org/opensearch/common/lucene/uid/VersionsTests.java
+++ b/server/src/test/java/org/opensearch/common/lucene/uid/VersionsTests.java
@@ -43,10 +43,10 @@
 import org.opensearch.Version;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.VersionFieldMapper;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -224,7 +224,7 @@ public void testLuceneVersionOnUnknownVersions() {
         assertEquals(VersionUtils.getFirstVersion().luceneVersion.major - 1, version.luceneVersion.major);
 
         // future version, should be the same version as today
-        version = Version.fromString("2.77.1");
+        version = Version.fromString(Version.CURRENT.major + ".77.1");
         assertEquals(Version.CURRENT.luceneVersion, version.luceneVersion);
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/network/NetworkModuleTests.java b/server/src/test/java/org/opensearch/common/network/NetworkModuleTests.java
index 3761781050c5b..0ca118fe422a5 100644
--- a/server/src/test/java/org/opensearch/common/network/NetworkModuleTests.java
+++ b/server/src/test/java/org/opensearch/common/network/NetworkModuleTests.java
@@ -32,21 +32,23 @@
 
 package org.opensearch.common.network;
 
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpStats;
 import org.opensearch.http.NullDispatcher;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.plugins.NetworkPlugin;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -116,7 +118,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 PageCacheRecycler pageCacheRecycler,
                 CircuitBreakerService circuitBreakerService,
                 NamedWriteableRegistry namedWriteableRegistry,
-                NetworkService networkService
+                NetworkService networkService,
+                Tracer tracer
             ) {
                 return Collections.singletonMap("custom", custom);
             }
@@ -143,7 +146,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
                 NamedXContentRegistry xContentRegistry,
                 NetworkService networkService,
                 HttpServerTransport.Dispatcher requestDispatcher,
-                ClusterSettings clusterSettings
+                ClusterSettings clusterSettings,
+                Tracer tracer
             ) {
                 return Collections.singletonMap("custom", custom);
             }
@@ -173,7 +177,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 PageCacheRecycler pageCacheRecycler,
                 CircuitBreakerService circuitBreakerService,
                 NamedWriteableRegistry namedWriteableRegistry,
-                NetworkService networkService
+                NetworkService networkService,
+                Tracer tracer
             ) {
                 return Collections.singletonMap("default_custom", customTransport);
             }
@@ -188,7 +193,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
                 NamedXContentRegistry xContentRegistry,
                 NetworkService networkService,
                 HttpServerTransport.Dispatcher requestDispatcher,
-                ClusterSettings clusterSettings
+                ClusterSettings clusterSettings,
+                Tracer tracer
             ) {
                 Map<String, Supplier<HttpServerTransport>> supplierMap = new HashMap<>();
                 supplierMap.put("custom", custom);
@@ -216,7 +222,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 PageCacheRecycler pageCacheRecycler,
                 CircuitBreakerService circuitBreakerService,
                 NamedWriteableRegistry namedWriteableRegistry,
-                NetworkService networkService
+                NetworkService networkService,
+                Tracer tracer
             ) {
                 return Collections.singletonMap("default_custom", customTransport);
             }
@@ -231,7 +238,8 @@ public Map<String, Supplier<HttpServerTransport>> getHttpTransports(
                 NamedXContentRegistry xContentRegistry,
                 NetworkService networkService,
                 HttpServerTransport.Dispatcher requestDispatcher,
-                ClusterSettings clusterSettings
+                ClusterSettings clusterSettings,
+                Tracer tracer
             ) {
                 Map<String, Supplier<HttpServerTransport>> supplierMap = new HashMap<>();
                 supplierMap.put("custom", custom);
@@ -313,7 +321,8 @@ private NetworkModule newNetworkModule(Settings settings, NetworkPlugin... plugi
             xContentRegistry(),
             null,
             new NullDispatcher(),
-            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            NoopTracer.INSTANCE
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/rounding/RoundingDuelTests.java b/server/src/test/java/org/opensearch/common/rounding/RoundingDuelTests.java
index 40f3224d89ff2..3088067cd1f84 100644
--- a/server/src/test/java/org/opensearch/common/rounding/RoundingDuelTests.java
+++ b/server/src/test/java/org/opensearch/common/rounding/RoundingDuelTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.common.rounding;
 
-import org.joda.time.DateTimeZone;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.test.OpenSearchTestCase;
+import org.joda.time.DateTimeZone;
 
 import java.time.ZoneOffset;
 
diff --git a/server/src/test/java/org/opensearch/common/rounding/TimeZoneRoundingTests.java b/server/src/test/java/org/opensearch/common/rounding/TimeZoneRoundingTests.java
index 0f9aa51b7b26e..8297f8fcf47e2 100644
--- a/server/src/test/java/org/opensearch/common/rounding/TimeZoneRoundingTests.java
+++ b/server/src/test/java/org/opensearch/common/rounding/TimeZoneRoundingTests.java
@@ -37,15 +37,15 @@
 import org.opensearch.common.rounding.Rounding.TimeUnitRounding;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.test.OpenSearchTestCase;
-import org.hamcrest.Description;
-import org.hamcrest.Matcher;
-import org.hamcrest.TypeSafeMatcher;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeConstants;
 import org.joda.time.DateTimeZone;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
 import org.joda.time.format.ISODateTimeFormat;
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/server/src/test/java/org/opensearch/common/settings/ConsistentSettingsServiceTests.java b/server/src/test/java/org/opensearch/common/settings/ConsistentSettingsServiceTests.java
index e7873723bec22..86bc124007829 100644
--- a/server/src/test/java/org/opensearch/common/settings/ConsistentSettingsServiceTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/ConsistentSettingsServiceTests.java
@@ -37,15 +37,16 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
-import org.mockito.Mockito;
-import org.mockito.stubbing.Answer;
 
 import java.util.Arrays;
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicReference;
 
-import static org.mockito.Mockito.mock;
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+
 import static org.hamcrest.Matchers.is;
+import static org.mockito.Mockito.mock;
 
 public class ConsistentSettingsServiceTests extends OpenSearchTestCase {
 
diff --git a/server/src/test/java/org/opensearch/common/settings/InsecureSettingTests.java b/server/src/test/java/org/opensearch/common/settings/InsecureSettingTests.java
new file mode 100644
index 0000000000000..b256ab956f963
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/settings/InsecureSettingTests.java
@@ -0,0 +1,113 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.settings;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.appender.AbstractAppender;
+import org.apache.logging.log4j.core.config.Property;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class InsecureSettingTests extends OpenSearchTestCase {
+    private List<String> rootLogMsgs = new ArrayList<>();
+    private AbstractAppender rootAppender;
+
+    protected void assertSettingWarning() {
+        assertWarnings(
+            "[setting.name] setting was deprecated in OpenSearch and will be removed in a future release! See the breaking changes documentation for the next major version."
+        );
+
+        Assert.assertTrue(
+            this.rootLogMsgs.stream()
+                .anyMatch(
+                    msg -> msg.equals(
+                        "Setting [setting.name] is insecure, but a secure variant [setting.name_secure] is advised to be used instead"
+                    )
+                )
+        );
+    }
+
+    @Before
+    public void addInsecureSettingsAppender() {
+        this.rootLogMsgs.clear();
+        rootAppender = new AbstractAppender("root", null, null, true, Property.EMPTY_ARRAY) {
+            @Override
+            public void append(LogEvent event) {
+                String message = event.getMessage().getFormattedMessage();
+                InsecureSettingTests.this.rootLogMsgs.add(message);
+            }
+        };
+        Loggers.addAppender(LogManager.getRootLogger(), rootAppender);
+        rootAppender.start();
+    }
+
+    @After
+    public void removeInsecureSettingsAppender() {
+        Loggers.removeAppender(LogManager.getRootLogger(), rootAppender);
+    }
+
+    public void testShouldRaiseExceptionByDefault() {
+        final var setting = SecureSetting.insecureString("setting.name");
+        final var settings = Settings.builder().put(setting.getKey(), "value").build();
+
+        final var exception = Assert.assertThrows(IllegalArgumentException.class, () -> setting.get(settings));
+        Assert.assertEquals(
+            "Setting [setting.name] is insecure, but property [allow_insecure_settings] is not set",
+            exception.getMessage()
+        );
+    }
+
+    public void testShouldLogWarn() {
+        final var setting = SecureSetting.insecureString("setting.name", "setting.name_secure", true);
+        final var settings = Settings.builder().put(setting.getKey(), "value").build();
+
+        Assert.assertEquals("value", setting.get(settings).toString());
+        assertSettingWarning();
+    }
+
+    public void testShouldLogWarnOnce() {
+        final var setting = SecureSetting.insecureString("setting.name", "setting.name_secure", true);
+        final var settings = Settings.builder().put(setting.getKey(), "value").build();
+
+        Assert.assertEquals("value", setting.get(settings).toString());
+        Assert.assertEquals("value", setting.get(settings).toString());
+        assertSettingWarning();
+
+        // check that warning was only logged once
+        Assert.assertEquals(1, this.rootLogMsgs.stream().filter(msg -> msg.contains("but a secure variant")).count());
+
+    }
+
+    public void testShouldRaiseExceptionIfConfigured() {
+        final var setting = SecureSetting.insecureString("setting.name", "setting.name_secure", false);
+        final var settings = Settings.builder().put(setting.getKey(), "value").build();
+
+        final var exception = Assert.assertThrows(IllegalArgumentException.class, () -> setting.get(settings));
+        Assert.assertEquals(
+            "Setting [setting.name] is insecure, but property [allow_insecure_settings] is not set",
+            exception.getMessage()
+        );
+    }
+
+    public void testShouldFallbackToInsecure() {
+        final var insecureSetting = SecureSetting.insecureString("setting.name", "setting.name_secure", true);
+        final var secureSetting = SecureSetting.secureString("setting.name_secure", insecureSetting);
+        final var settings = Settings.builder().put(insecureSetting.getKey(), "value").build();
+
+        Assert.assertEquals("value", secureSetting.get(settings).toString());
+        assertSettingWarning();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/settings/MemorySizeSettingsTests.java b/server/src/test/java/org/opensearch/common/settings/MemorySizeSettingsTests.java
index f64b45e80dbca..95db7c2cfacaa 100644
--- a/server/src/test/java/org/opensearch/common/settings/MemorySizeSettingsTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/MemorySizeSettingsTests.java
@@ -33,9 +33,8 @@
 package org.opensearch.common.settings;
 
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.indices.IndexingMemoryController;
 import org.opensearch.indices.IndicesQueryCache;
 import org.opensearch.indices.IndicesRequestCache;
@@ -44,9 +43,9 @@
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.test.OpenSearchTestCase;
 
-import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
+import static org.hamcrest.Matchers.notNullValue;
 
 public class MemorySizeSettingsTests extends OpenSearchTestCase {
 
@@ -83,9 +82,13 @@ public void testIndicesRequestCacheSetting() {
     }
 
     public void testCircuitBreakerSettings() {
-        // default is chosen based on actual heap size
+        final Settings settings = Settings.builder()
+            .put(HierarchyCircuitBreakerService.USE_REAL_MEMORY_USAGE_SETTING.getKey(), randomBoolean())
+            .build();
+
+        // default is chosen based on USE_REAL_MEMORY_USAGE_SETTING setting
         double defaultTotalPercentage;
-        if (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() < new ByteSizeValue(1, ByteSizeUnit.GB).getBytes()) {
+        if (HierarchyCircuitBreakerService.USE_REAL_MEMORY_USAGE_SETTING.get(settings)) {
             defaultTotalPercentage = 0.95d;
         } else {
             defaultTotalPercentage = 0.7d;
@@ -93,22 +96,26 @@ public void testCircuitBreakerSettings() {
         assertMemorySizeSetting(
             HierarchyCircuitBreakerService.TOTAL_CIRCUIT_BREAKER_LIMIT_SETTING,
             "indices.breaker.total.limit",
-            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * defaultTotalPercentage))
+            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * defaultTotalPercentage)),
+            settings
         );
         assertMemorySizeSetting(
             HierarchyCircuitBreakerService.FIELDDATA_CIRCUIT_BREAKER_LIMIT_SETTING,
             "indices.breaker.fielddata.limit",
-            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.4))
+            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.4)),
+            settings
         );
         assertMemorySizeSetting(
             HierarchyCircuitBreakerService.REQUEST_CIRCUIT_BREAKER_LIMIT_SETTING,
             "indices.breaker.request.limit",
-            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.6))
+            new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.6)),
+            settings
         );
         assertMemorySizeSetting(
             HierarchyCircuitBreakerService.IN_FLIGHT_REQUESTS_CIRCUIT_BREAKER_LIMIT_SETTING,
             "network.breaker.inflight_requests.limit",
-            new ByteSizeValue((JvmInfo.jvmInfo().getMem().getHeapMax().getBytes()))
+            new ByteSizeValue((JvmInfo.jvmInfo().getMem().getHeapMax().getBytes())),
+            settings
         );
     }
 
@@ -121,10 +128,14 @@ public void testIndicesFieldDataCacheSetting() {
     }
 
     private void assertMemorySizeSetting(Setting<ByteSizeValue> setting, String settingKey, ByteSizeValue defaultValue) {
+        assertMemorySizeSetting(setting, settingKey, defaultValue, Settings.EMPTY);
+    }
+
+    private void assertMemorySizeSetting(Setting<ByteSizeValue> setting, String settingKey, ByteSizeValue defaultValue, Settings settings) {
         assertThat(setting, notNullValue());
         assertThat(setting.getKey(), equalTo(settingKey));
         assertThat(setting.getProperties(), hasItem(Property.NodeScope));
-        assertThat(setting.getDefault(Settings.EMPTY), equalTo(defaultValue));
+        assertThat(setting.getDefault(settings), equalTo(defaultValue));
         Settings settingWithPercentage = Settings.builder().put(settingKey, "25%").build();
         assertThat(
             setting.get(settingWithPercentage),
diff --git a/server/src/test/java/org/opensearch/common/settings/PropertyPlaceholderTests.java b/server/src/test/java/org/opensearch/common/settings/PropertyPlaceholderTests.java
index c3c8666b83959..c4fbb27cb80e0 100644
--- a/server/src/test/java/org/opensearch/common/settings/PropertyPlaceholderTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/PropertyPlaceholderTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.common.settings;
 
+import org.opensearch.test.OpenSearchTestCase;
+
 import java.util.LinkedHashMap;
 import java.util.Map;
 
-import org.opensearch.test.OpenSearchTestCase;
-
 import static org.hamcrest.Matchers.is;
 
 public class PropertyPlaceholderTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/common/settings/SecureStringTests.java b/server/src/test/java/org/opensearch/common/settings/SecureStringTests.java
index 519def6c244aa..45af07cf1dacd 100644
--- a/server/src/test/java/org/opensearch/common/settings/SecureStringTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/SecureStringTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.common.settings;
 
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
diff --git a/server/src/test/java/org/opensearch/common/settings/SettingTests.java b/server/src/test/java/org/opensearch/common/settings/SettingTests.java
index 7703cb394397e..13cecc7157d82 100644
--- a/server/src/test/java/org/opensearch/common/settings/SettingTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/SettingTests.java
@@ -37,15 +37,27 @@
 import org.apache.logging.log4j.core.LogEvent;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.AbstractScopedSettings.SettingUpdater;
+import org.opensearch.common.settings.Setting.ByteSizeValueParser;
+import org.opensearch.common.settings.Setting.DoubleParser;
+import org.opensearch.common.settings.Setting.FloatParser;
+import org.opensearch.common.settings.Setting.IntegerParser;
+import org.opensearch.common.settings.Setting.LongParser;
+import org.opensearch.common.settings.Setting.MemorySizeValueParser;
+import org.opensearch.common.settings.Setting.MinMaxTimeValueParser;
+import org.opensearch.common.settings.Setting.MinTimeValueParser;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.common.settings.Setting.RegexValidator;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.monitor.jvm.JvmInfo;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 
 import java.util.Arrays;
@@ -58,6 +70,7 @@
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -311,14 +324,66 @@ public void testValidator() {
         assertTrue(FooBarValidator.invokedWithDependencies);
     }
 
+    public void testRegexValidator() throws Exception {
+        // A regex that matches one or more digits
+        String expectedRegex = "\\d+";
+        Pattern expectedPattern = Pattern.compile(expectedRegex);
+        RegexValidator regexValidator = new RegexValidator(expectedRegex);
+        RegexValidator regexValidatorMatcherFalse = new RegexValidator(expectedRegex, false);
+
+        // Test that the pattern is correctly initialized
+        assertNotNull(expectedPattern);
+        assertNotNull(regexValidator.getPattern());
+        assertEquals(expectedPattern.pattern(), regexValidator.getPattern().pattern());
+
+        // Test that checks the pattern and isMatching with the set value false parameters are working correctly during initialization
+        assertNotNull(regexValidatorMatcherFalse);
+        assertNotNull(regexValidatorMatcherFalse.getPattern());
+        assertEquals(expectedPattern.pattern(), regexValidatorMatcherFalse.getPattern().pattern());
+
+        // Test throw an exception when the value does not match
+        final RegexValidator finalValidator = new RegexValidator(expectedRegex);
+        assertThrows(IllegalArgumentException.class, () -> finalValidator.validate("foo"));
+        try {
+            regexValidator.validate("123");
+        } catch (IllegalArgumentException e) {
+            fail("Expected validate() to not throw an exception, but it threw " + e);
+        }
+
+        // Test throws an exception when the value matches
+        final RegexValidator finalValidatorFalse = new RegexValidator(expectedRegex);
+        assertThrows(IllegalArgumentException.class, () -> finalValidatorFalse.validate(expectedRegex));
+        try {
+            regexValidatorMatcherFalse.validate(expectedRegex);
+        } catch (IllegalArgumentException e) {
+            fail("Expected validate() to not throw an exception, but it threw " + e);
+        }
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            regexValidator.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                regexValidator = new RegexValidator(in);
+                assertEquals(expectedPattern.pattern(), regexValidator.getPattern().pattern());
+
+                // Test that validate() throws an exception for invalid input
+                final RegexValidator newFinalValidator = new RegexValidator(expectedRegex);
+                assertThrows(IllegalArgumentException.class, () -> newFinalValidator.validate("foo"));
+
+                // Test that validate() does not throw an exception for valid input
+                try {
+                    regexValidator.validate("123");
+                } catch (IllegalArgumentException e) {
+                    fail("Expected validate() to not throw an exception, but it threw " + e);
+                }
+            }
+        }
+    }
+
     public void testValidatorForFilteredStringSetting() {
-        final Setting<String> filteredStringSetting = new Setting<>(
-            "foo.bar",
-            "foobar",
-            Function.identity(),
-            value -> { throw new SettingsException("validate always fails"); },
-            Property.Filtered
-        );
+        final Setting<String> filteredStringSetting = new Setting<>("foo.bar", "foobar", Function.identity(), value -> {
+            throw new SettingsException("validate always fails");
+        }, Property.Filtered);
 
         final Settings settings = Settings.builder().put(filteredStringSetting.getKey(), filteredStringSetting.getKey() + " value").build();
         final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> filteredStringSetting.get(settings));
@@ -1045,6 +1110,31 @@ public void testIntWithMinMax() {
         assertEquals(1, integerSetting.get(Settings.EMPTY).intValue());
     }
 
+    public void testIntegerParser() throws Exception {
+        String expectedKey = "test key";
+        int expectedMinValue = Integer.MIN_VALUE;
+        int expectedMaxValue = Integer.MAX_VALUE;
+        boolean expectedFilteredStatus = true;
+        IntegerParser integerParser = new IntegerParser(expectedMinValue, expectedMaxValue, expectedKey, expectedFilteredStatus);
+
+        assertEquals(expectedKey, integerParser.getKey());
+        assertEquals(expectedMinValue, integerParser.getMin());
+        assertEquals(expectedMaxValue, integerParser.getMax());
+        assertEquals(expectedFilteredStatus, integerParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            integerParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                integerParser = new IntegerParser(in);
+                assertEquals(expectedKey, integerParser.getKey());
+                assertEquals(expectedMinValue, integerParser.getMin());
+                assertEquals(expectedMaxValue, integerParser.getMax());
+                assertEquals(expectedFilteredStatus, integerParser.getFilterStatus());
+            }
+        }
+    }
+
     // Long
 
     public void testLongWithDefaultValue() {
@@ -1080,6 +1170,31 @@ public void testLongWithMinMax() {
         assertEquals(1, longSetting.get(Settings.EMPTY).longValue());
     }
 
+    public void testLongParser() throws Exception {
+        String expectedKey = "test key";
+        long expectedMinValue = Long.MIN_VALUE;
+        long expectedMaxValue = Long.MAX_VALUE;
+        boolean expectedFilteredStatus = true;
+        LongParser longParser = new LongParser(expectedMinValue, expectedMaxValue, expectedKey, expectedFilteredStatus);
+
+        assertEquals(expectedKey, longParser.getKey());
+        assertEquals(expectedMinValue, longParser.getMin());
+        assertEquals(expectedMaxValue, longParser.getMax());
+        assertEquals(expectedFilteredStatus, longParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            longParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                longParser = new LongParser(in);
+                assertEquals(expectedKey, longParser.getKey());
+                assertEquals(expectedMinValue, longParser.getMin());
+                assertEquals(expectedMaxValue, longParser.getMax());
+                assertEquals(expectedFilteredStatus, longParser.getFilterStatus());
+            }
+        }
+    }
+
     // Float
 
     public void testFloatWithDefaultValue() {
@@ -1115,6 +1230,31 @@ public void testFloatWithMinMax() {
         assertEquals(1.2, floatSetting.get(Settings.EMPTY).floatValue(), 0.01);
     }
 
+    public void testFloatParser() throws Exception {
+        String expectedKey = "test key";
+        float expectedMinValue = Float.MIN_VALUE;
+        float expectedMaxValue = Float.MAX_VALUE;
+        boolean expectedFilteredStatus = true;
+        FloatParser floatParser = new FloatParser(expectedMinValue, expectedMaxValue, expectedKey, expectedFilteredStatus);
+
+        assertEquals(expectedKey, floatParser.getKey());
+        assertEquals(expectedMinValue, floatParser.getMin(), 0.01);
+        assertEquals(expectedMaxValue, floatParser.getMax(), 0.01);
+        assertEquals(expectedFilteredStatus, floatParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            floatParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                floatParser = new FloatParser(in);
+                assertEquals(expectedKey, floatParser.getKey());
+                assertEquals(expectedMinValue, floatParser.getMin(), 0.01);
+                assertEquals(expectedMaxValue, floatParser.getMax(), 0.01);
+                assertEquals(expectedFilteredStatus, floatParser.getFilterStatus());
+            }
+        }
+    }
+
     // Double
 
     public void testDoubleWithDefaultValue() {
@@ -1130,7 +1270,7 @@ public void testDoubleWithFallbackValue() {
         assertEquals(doubleSetting.get(Settings.builder().put("foo.baz", 3.2).build()), Double.valueOf(3.2));
     }
 
-    public void testDoubleWithMinMax() {
+    public void testDoubleWithMinMax() throws Exception {
         Setting<Double> doubleSetting = Setting.doubleSetting("foo.bar", 1.2, 0, 10, Property.NodeScope);
         try {
             doubleSetting.get(Settings.builder().put("foo.bar", 11.3).build());
@@ -1150,6 +1290,71 @@ public void testDoubleWithMinMax() {
         assertEquals(1.2, doubleSetting.get(Settings.EMPTY).doubleValue(), 0.01);
     }
 
+    public void testDoubleParser() throws Exception {
+        String expectedKey = "test key";
+        double expectedMinValue = Double.MIN_VALUE;
+        double expectedMaxValue = Double.MAX_VALUE;
+        boolean expectedFilteredStatus = true;
+        DoubleParser doubleParser = new DoubleParser(expectedMinValue, expectedMaxValue, expectedKey, expectedFilteredStatus);
+
+        assertEquals(expectedKey, doubleParser.getKey());
+        assertEquals(expectedMinValue, doubleParser.getMin(), 0.01);
+        assertEquals(expectedMaxValue, doubleParser.getMax(), 0.01);
+        assertEquals(expectedFilteredStatus, doubleParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            doubleParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                doubleParser = new DoubleParser(in);
+                assertEquals(expectedKey, doubleParser.getKey());
+                assertEquals(expectedMinValue, doubleParser.getMin(), 0.01);
+                assertEquals(expectedMaxValue, doubleParser.getMax(), 0.01);
+                assertEquals(expectedFilteredStatus, doubleParser.getFilterStatus());
+            }
+        }
+    }
+
+    // ByteSizeValue
+    public void testByteSizeValueParser() throws Exception {
+        String expectedKey = "test key";
+        ByteSizeValue expectedMinValue = new ByteSizeValue((long) 1);
+        ByteSizeValue expectedMaxValue = new ByteSizeValue(Long.MAX_VALUE);
+        ByteSizeValueParser byteSizeValueParser = new ByteSizeValueParser(expectedMinValue, expectedMaxValue, expectedKey);
+
+        assertEquals(expectedKey, byteSizeValueParser.getKey());
+        assertEquals(expectedMinValue, byteSizeValueParser.getMin());
+        assertEquals(expectedMaxValue, byteSizeValueParser.getMax());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            byteSizeValueParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                byteSizeValueParser = new ByteSizeValueParser(in);
+                assertEquals(expectedKey, byteSizeValueParser.getKey());
+                assertEquals(expectedMinValue, byteSizeValueParser.getMin());
+                assertEquals(expectedMaxValue, byteSizeValueParser.getMax());
+            }
+        }
+    }
+
+    // MemorySizeValue
+    public void testMemorySizeValueParser() throws Exception {
+        String expectedKey = "test key";
+        MemorySizeValueParser memorySizeValueParser = new MemorySizeValueParser(expectedKey);
+
+        assertEquals(expectedKey, memorySizeValueParser.getKey());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            memorySizeValueParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                memorySizeValueParser = new MemorySizeValueParser(in);
+                assertEquals(expectedKey, memorySizeValueParser.getKey());
+            }
+        }
+    }
+
     /**
      * Only one single scope can be added to any setting
      */
@@ -1228,6 +1433,58 @@ public void testTimeValue() {
         assertThat(setting.get(Settings.EMPTY).getMillis(), equalTo(random.getMillis() * factor));
     }
 
+    public void testMinTimeValueParser() throws Exception {
+        String expectedKey = "test key";
+        TimeValue expectedMinValue = TimeValue.timeValueSeconds(0);
+        boolean expectedFilteredStatus = true;
+        MinTimeValueParser minTimeValueParser = new MinTimeValueParser(expectedKey, expectedMinValue, expectedFilteredStatus);
+
+        assertEquals(expectedKey, minTimeValueParser.getKey());
+        assertEquals(expectedMinValue, minTimeValueParser.getMin());
+        assertEquals(expectedFilteredStatus, minTimeValueParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            minTimeValueParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                minTimeValueParser = new MinTimeValueParser(in);
+                assertEquals(expectedKey, minTimeValueParser.getKey());
+                assertEquals(expectedMinValue, minTimeValueParser.getMin());
+                assertEquals(expectedFilteredStatus, minTimeValueParser.getFilterStatus());
+            }
+        }
+    }
+
+    public void testMinMaxTimeValueParser() throws Exception {
+        String expectedKey = "test key";
+        TimeValue expectedMinValue = TimeValue.timeValueSeconds(0);
+        TimeValue expectedMaxValue = TimeValue.MAX_VALUE;
+        boolean expectedFilteredStatus = true;
+        MinMaxTimeValueParser minMaxTimeValueParser = new MinMaxTimeValueParser(
+            expectedKey,
+            expectedMinValue,
+            expectedMaxValue,
+            expectedFilteredStatus
+        );
+
+        assertEquals(expectedKey, minMaxTimeValueParser.getKey());
+        assertEquals(expectedMinValue, minMaxTimeValueParser.getMin());
+        assertEquals(expectedMaxValue, minMaxTimeValueParser.getMax());
+        assertEquals(expectedFilteredStatus, minMaxTimeValueParser.getFilterStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            minMaxTimeValueParser.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                minMaxTimeValueParser = new MinMaxTimeValueParser(in);
+                assertEquals(expectedKey, minMaxTimeValueParser.getKey());
+                assertEquals(expectedMinValue, minMaxTimeValueParser.getMin());
+                assertEquals(expectedMaxValue, minMaxTimeValueParser.getMax());
+                assertEquals(expectedFilteredStatus, minMaxTimeValueParser.getFilterStatus());
+            }
+        }
+    }
+
     public void testTimeValueBounds() {
         Setting<TimeValue> settingWithLowerBound = Setting.timeSetting(
             "foo",
@@ -1381,16 +1638,14 @@ public void testGroupSettingUpdaterValidator() {
             validator
         );
 
-        IllegalArgumentException illegal = expectThrows(
-            IllegalArgumentException.class,
-            () -> { updater.getValue(Settings.builder().put("prefix.foo.suffix", 5).put("abc", 2).build(), Settings.EMPTY); }
-        );
+        IllegalArgumentException illegal = expectThrows(IllegalArgumentException.class, () -> {
+            updater.getValue(Settings.builder().put("prefix.foo.suffix", 5).put("abc", 2).build(), Settings.EMPTY);
+        });
         assertEquals("foo and 2 can't go together", illegal.getMessage());
 
-        illegal = expectThrows(
-            IllegalArgumentException.class,
-            () -> { updater.getValue(Settings.builder().put("prefix.bar.suffix", 6).put("abc", 3).build(), Settings.EMPTY); }
-        );
+        illegal = expectThrows(IllegalArgumentException.class, () -> {
+            updater.getValue(Settings.builder().put("prefix.bar.suffix", 6).put("abc", 3).build(), Settings.EMPTY);
+        });
         assertEquals("no bar", illegal.getMessage());
 
         Settings s = updater.getValue(
diff --git a/server/src/test/java/org/opensearch/common/settings/SettingsFilterTests.java b/server/src/test/java/org/opensearch/common/settings/SettingsFilterTests.java
index 078917116beb5..75b6078fc4ea1 100644
--- a/server/src/test/java/org/opensearch/common/settings/SettingsFilterTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/SettingsFilterTests.java
@@ -32,15 +32,14 @@
 package org.opensearch.common.settings;
 
 import org.apache.logging.log4j.Level;
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
-import org.opensearch.common.Strings;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 
 import java.io.IOException;
@@ -163,7 +162,7 @@ private void testFiltering(Settings source, Settings filtered, String... pattern
         xContentBuilder.startObject();
         source.toXContent(xContentBuilder, request);
         xContentBuilder.endObject();
-        String filteredSettingsString = Strings.toString(xContentBuilder);
+        String filteredSettingsString = xContentBuilder.toString();
         filteredSettings = Settings.builder().loadFromSource(filteredSettingsString, xContentBuilder.contentType()).build();
         assertThat(filteredSettings, equalTo(filtered));
     }
diff --git a/server/src/test/java/org/opensearch/common/settings/SettingsModuleTests.java b/server/src/test/java/org/opensearch/common/settings/SettingsModuleTests.java
index a8306107aaccc..df34c19dbab8e 100644
--- a/server/src/test/java/org/opensearch/common/settings/SettingsModuleTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/SettingsModuleTests.java
@@ -34,6 +34,11 @@
 
 import org.opensearch.common.inject.ModuleTestCase;
 import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.search.SearchBootstrapSettings;
+import org.opensearch.search.SearchService;
+import org.opensearch.test.FeatureFlagSetter;
 import org.hamcrest.Matchers;
 
 import java.util.Arrays;
@@ -237,4 +242,130 @@ public void testOldMaxClauseCountSetting() {
             ex.getMessage()
         );
     }
+
+    public void testDynamicNodeSettingsRegistration() {
+        FeatureFlagSetter.set(FeatureFlags.EXTENSIONS);
+        Settings settings = Settings.builder().put("some.custom.setting", "2.0").build();
+        SettingsModule module = new SettingsModule(settings, Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope));
+        assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+        // For unregistered setting the value is expected to be null
+        assertNull(module.getClusterSettings().get("some.custom.setting2"));
+        assertInstanceBinding(module, Settings.class, (s) -> s == settings);
+
+        assertTrue(module.registerDynamicSetting(Setting.floatSetting("some.custom.setting2", 1.0f, Property.NodeScope)));
+        assertNotNull(module.getClusterSettings().get("some.custom.setting2"));
+        // verify if some.custom.setting still exists
+        assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+
+        // verify exception is thrown when setting registration fails
+        expectThrows(
+            SettingsException.class,
+            () -> module.registerDynamicSetting(Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope))
+        );
+    }
+
+    public void testDynamicIndexSettingsRegistration() {
+        FeatureFlagSetter.set(FeatureFlags.EXTENSIONS);
+        Settings settings = Settings.builder().put("some.custom.setting", "2.0").build();
+        SettingsModule module = new SettingsModule(settings, Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope));
+        assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+        // For unregistered setting the value is expected to be null
+        assertNull(module.getIndexScopedSettings().get("index.custom.setting2"));
+        assertInstanceBinding(module, Settings.class, (s) -> s == settings);
+
+        assertTrue(module.registerDynamicSetting(Setting.floatSetting("index.custom.setting2", 1.0f, Property.IndexScope)));
+        assertNotNull(module.getIndexScopedSettings().get("index.custom.setting2"));
+
+        // verify if some.custom.setting still exists
+        assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+
+        // verify exception is thrown when setting registration fails
+        expectThrows(
+            SettingsException.class,
+            () -> module.registerDynamicSetting(Setting.floatSetting("index.custom.setting2", 1.0f, Property.IndexScope))
+        );
+    }
+
+    public void testConcurrentSegmentSearchClusterSettings() {
+        // Test that we throw an exception without the feature flag
+        Settings settings = Settings.builder().put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build();
+        IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> new SettingsModule(settings));
+        assertEquals(
+            "unknown setting ["
+                + SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey()
+                + "] please check that any required plugins are installed, or check the breaking "
+                + "changes documentation for removed settings",
+            ex.getMessage()
+        );
+
+        // Test that the settings updates correctly with the feature flag
+        FeatureFlagSetter.set(FeatureFlags.CONCURRENT_SEGMENT_SEARCH);
+        boolean settingValue = randomBoolean();
+        Settings settingsWithFeatureFlag = Settings.builder()
+            .put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), settingValue)
+            .build();
+        SettingsModule settingsModule = new SettingsModule(settingsWithFeatureFlag);
+        assertEquals(settingValue, SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.get(settingsModule.getSettings()));
+    }
+
+    public void testConcurrentSegmentSearchIndexSettings() {
+        Settings.Builder target = Settings.builder().put(Settings.EMPTY);
+        Settings.Builder update = Settings.builder();
+
+        // Test that we throw an exception without the feature flag
+        SettingsModule module = new SettingsModule(Settings.EMPTY);
+        IndexScopedSettings indexScopedSettings = module.getIndexScopedSettings();
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> indexScopedSettings.updateDynamicSettings(
+                Settings.builder().put(IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build(),
+                target,
+                update,
+                "node"
+            )
+        );
+
+        // Test that the settings updates correctly with the feature flag
+        FeatureFlagSetter.set(FeatureFlags.CONCURRENT_SEGMENT_SEARCH);
+        SettingsModule moduleWithFeatureFlag = new SettingsModule(Settings.EMPTY);
+        IndexScopedSettings indexScopedSettingsWithFeatureFlag = moduleWithFeatureFlag.getIndexScopedSettings();
+        indexScopedSettingsWithFeatureFlag.updateDynamicSettings(
+            Settings.builder().put(IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build(),
+            target,
+            update,
+            "node"
+        );
+    }
+
+    public void testMaxSliceCountClusterSettingsForConcurrentSearch() {
+        // Test that we throw an exception without the feature flag
+        Settings settings = Settings.builder()
+            .put(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.getKey(), true)
+            .build();
+        IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> new SettingsModule(settings));
+        assertTrue(
+            ex.getMessage()
+                .contains("unknown setting [" + SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.getKey())
+        );
+
+        // Test that the settings updates correctly with the feature flag
+        FeatureFlagSetter.set(FeatureFlags.CONCURRENT_SEGMENT_SEARCH);
+        int settingValue = randomIntBetween(0, 10);
+        Settings settingsWithFeatureFlag = Settings.builder()
+            .put(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.getKey(), settingValue)
+            .build();
+        SettingsModule settingsModule = new SettingsModule(settingsWithFeatureFlag);
+        assertEquals(
+            settingValue,
+            (int) SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.get(settingsModule.getSettings())
+        );
+
+        // Test that negative value is not allowed
+        settingValue = -1;
+        final Settings settingsWithFeatureFlag_2 = Settings.builder()
+            .put(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.getKey(), settingValue)
+            .build();
+        ex = expectThrows(IllegalArgumentException.class, () -> new SettingsModule(settingsWithFeatureFlag_2));
+        assertTrue(ex.getMessage().contains(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING.getKey()));
+    }
 }
diff --git a/server/src/test/java/org/opensearch/common/settings/SettingsTests.java b/server/src/test/java/org/opensearch/common/settings/SettingsTests.java
index 6848cd2bbc773..dc116582e4103 100644
--- a/server/src/test/java/org/opensearch/common/settings/SettingsTests.java
+++ b/server/src/test/java/org/opensearch/common/settings/SettingsTests.java
@@ -35,17 +35,18 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.settings.SecureString;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
@@ -301,6 +302,20 @@ public void testPrefixNormalization() {
         assertThat(settings.get("foo.test"), equalTo("test"));
     }
 
+    public void testPrefixNormalizationArchived() {
+        Settings settings = Settings.builder().put("archived.foo.bar", "baz").normalizePrefix("foo.").build();
+
+        assertThat(settings.size(), equalTo(1));
+        assertThat(settings.get("foo.archived.foo.bar"), nullValue());
+        assertThat(settings.get("archived.foo.bar"), equalTo("baz"));
+
+        settings = Settings.builder().put("archived.foo.*", "baz").normalizePrefix("foo.").build();
+
+        assertThat(settings.size(), equalTo(1));
+        assertThat(settings.get("foo.archived.foo.*"), nullValue());
+        assertThat(settings.get("archived.foo.*"), equalTo("baz"));
+    }
+
     public void testFilteredMap() {
         Settings.Builder builder = Settings.builder();
         builder.put("a", "a1");
@@ -515,7 +530,7 @@ public void testToAndFromXContent() throws IOException {
             .putNull("foo.null.baz")
             .build();
         final boolean flatSettings = randomBoolean();
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
         builder.startObject();
         settings.toXContent(builder, new ToXContent.MapParams(Collections.singletonMap("flat_settings", "" + flatSettings)));
         builder.endObject();
@@ -548,24 +563,24 @@ public void testSimpleJsonSettings() throws Exception {
     public void testToXContent() throws IOException {
         // this is just terrible but it's the existing behavior!
         Settings test = Settings.builder().putList("foo.bar", "1", "2", "3").put("foo.bar.baz", "test").build();
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         builder.startObject();
         test.toXContent(builder, new ToXContent.MapParams(Collections.emptyMap()));
         builder.endObject();
-        assertEquals("{\"foo\":{\"bar.baz\":\"test\",\"bar\":[\"1\",\"2\",\"3\"]}}", Strings.toString(builder));
+        assertEquals("{\"foo\":{\"bar.baz\":\"test\",\"bar\":[\"1\",\"2\",\"3\"]}}", builder.toString());
 
         test = Settings.builder().putList("foo.bar", "1", "2", "3").build();
-        builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         builder.startObject();
         test.toXContent(builder, new ToXContent.MapParams(Collections.emptyMap()));
         builder.endObject();
-        assertEquals("{\"foo\":{\"bar\":[\"1\",\"2\",\"3\"]}}", Strings.toString(builder));
+        assertEquals("{\"foo\":{\"bar\":[\"1\",\"2\",\"3\"]}}", builder.toString());
 
-        builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         builder.startObject();
         test.toXContent(builder, new ToXContent.MapParams(Collections.singletonMap("flat_settings", "true")));
         builder.endObject();
-        assertEquals("{\"foo.bar\":[\"1\",\"2\",\"3\"]}", Strings.toString(builder));
+        assertEquals("{\"foo.bar\":[\"1\",\"2\",\"3\"]}", builder.toString());
     }
 
     public void testLoadEmptyStream() throws IOException {
@@ -606,19 +621,17 @@ public void testYamlLegacyList() throws IOException {
 
     public void testIndentation() throws Exception {
         String yaml = "/org/opensearch/common/settings/loader/indentation-settings.yml";
-        OpenSearchParseException e = expectThrows(
-            OpenSearchParseException.class,
-            () -> { Settings.builder().loadFromStream(yaml, getClass().getResourceAsStream(yaml), false); }
-        );
+        OpenSearchParseException e = expectThrows(OpenSearchParseException.class, () -> {
+            Settings.builder().loadFromStream(yaml, getClass().getResourceAsStream(yaml), false);
+        });
         assertTrue(e.getMessage(), e.getMessage().contains("malformed"));
     }
 
     public void testIndentationWithExplicitDocumentStart() throws Exception {
         String yaml = "/org/opensearch/common/settings/loader/indentation-with-explicit-document-start-settings.yml";
-        OpenSearchParseException e = expectThrows(
-            OpenSearchParseException.class,
-            () -> { Settings.builder().loadFromStream(yaml, getClass().getResourceAsStream(yaml), false); }
-        );
+        OpenSearchParseException e = expectThrows(OpenSearchParseException.class, () -> {
+            Settings.builder().loadFromStream(yaml, getClass().getResourceAsStream(yaml), false);
+        });
         assertTrue(e.getMessage(), e.getMessage().contains("malformed"));
     }
 
@@ -710,18 +723,18 @@ public void testSetByTimeUnit() {
 
     public void testProcessSetting() throws IOException {
         Settings test = Settings.builder().put("ant", "value1").put("ant.bee.cat", "value2").put("bee.cat", "value3").build();
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         builder.startObject();
         test.toXContent(builder, new ToXContent.MapParams(Collections.emptyMap()));
         builder.endObject();
-        assertEquals("{\"ant.bee\":{\"cat\":\"value2\"},\"ant\":\"value1\",\"bee\":{\"cat\":\"value3\"}}", Strings.toString(builder));
+        assertEquals("{\"ant.bee\":{\"cat\":\"value2\"},\"ant\":\"value1\",\"bee\":{\"cat\":\"value3\"}}", builder.toString());
 
         test = Settings.builder().put("ant", "value1").put("ant.bee.cat", "value2").put("ant.bee.cat.dog.ewe", "value3").build();
-        builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        builder = XContentBuilder.builder(MediaTypeRegistry.JSON.xContent());
         builder.startObject();
         test.toXContent(builder, new ToXContent.MapParams(Collections.emptyMap()));
         builder.endObject();
-        assertEquals("{\"ant.bee\":{\"cat.dog\":{\"ewe\":\"value3\"},\"cat\":\"value2\"},\"ant\":\"value1\"}", Strings.toString(builder));
+        assertEquals("{\"ant.bee\":{\"cat.dog\":{\"ewe\":\"value3\"},\"cat\":\"value2\"},\"ant\":\"value1\"}", builder.toString());
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/common/settings/WriteableSettingTests.java b/server/src/test/java/org/opensearch/common/settings/WriteableSettingTests.java
new file mode 100644
index 0000000000000..391f3d3116430
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/settings/WriteableSettingTests.java
@@ -0,0 +1,461 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.settings;
+
+import org.opensearch.Version;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.common.settings.Setting.Property;
+import static org.opensearch.common.settings.WriteableSetting.SettingType;
+
+public class WriteableSettingTests extends OpenSearchTestCase {
+
+    // These settings have a default value and null fallback
+    private final Map<SettingType, Setting<?>> settingMap = new EnumMap<>(SettingType.class);
+    // These settings have a fallback setting instead of a default
+    private final Map<SettingType, Setting<?>> settingWithFallbackMap = new EnumMap<>(SettingType.class);
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setup() throws Exception {
+        super.setUp();
+        settingMap.put(SettingType.Boolean, Setting.boolSetting("boolSettingBase", false, Property.NodeScope, Property.Dynamic));
+        settingMap.put(SettingType.Integer, Setting.intSetting("intSettingBase", 6, Property.NodeScope, Property.Dynamic));
+        settingMap.put(SettingType.Long, Setting.longSetting("longSettingBase", 42L, Property.NodeScope, Property.Dynamic));
+        settingMap.put(SettingType.Float, Setting.floatSetting("floatSettingBase", 6.2f, Property.NodeScope, Property.Dynamic));
+        settingMap.put(SettingType.Double, Setting.doubleSetting("doubleSettingBase", 42.2d, Property.NodeScope, Property.Dynamic));
+        settingMap.put(SettingType.String, Setting.simpleString("simpleStringBase", "foo", Property.NodeScope, Property.Dynamic));
+        settingMap.put(
+            SettingType.TimeValue,
+            Setting.timeSetting("timeSettingBase", new TimeValue(5, TimeUnit.MILLISECONDS), Property.NodeScope, Property.Dynamic)
+        );
+        settingMap.put(
+            SettingType.ByteSizeValue,
+            Setting.byteSizeSetting("byteSizeSettingBase", new ByteSizeValue(10, ByteSizeUnit.KB), Property.NodeScope, Property.Dynamic)
+        );
+        settingMap.put(
+            SettingType.Version,
+            Setting.versionSetting("versionSettingBase", Version.CURRENT, Property.NodeScope, Property.Dynamic)
+        );
+
+        settingWithFallbackMap.put(
+            SettingType.Boolean,
+            Setting.boolSetting("boolSetting", (Setting<Boolean>) settingMap.get(SettingType.Boolean), Property.NodeScope, Property.Dynamic)
+        );
+        settingWithFallbackMap.put(
+            SettingType.Integer,
+            Setting.intSetting("intSetting", (Setting<Integer>) settingMap.get(SettingType.Integer), Property.NodeScope, Property.Dynamic)
+        );
+        settingWithFallbackMap.put(
+            SettingType.Long,
+            Setting.longSetting("longSetting", (Setting<Long>) settingMap.get(SettingType.Long), Property.NodeScope, Property.Dynamic)
+        );
+        settingWithFallbackMap.put(
+            SettingType.Float,
+            Setting.floatSetting("floatSetting", (Setting<Float>) settingMap.get(SettingType.Float), Property.NodeScope, Property.Dynamic)
+        );
+        settingWithFallbackMap.put(
+            SettingType.Double,
+            Setting.doubleSetting(
+                "doubleSetting",
+                (Setting<Double>) settingMap.get(SettingType.Double),
+                Property.NodeScope,
+                Property.Dynamic
+            )
+        );
+        settingWithFallbackMap.put(
+            SettingType.String,
+            Setting.simpleString("simpleString", (Setting<String>) settingMap.get(SettingType.String), Property.NodeScope, Property.Dynamic)
+        );
+        settingWithFallbackMap.put(
+            SettingType.TimeValue,
+            Setting.timeSetting(
+                "timeSetting",
+                (Setting<TimeValue>) settingMap.get(SettingType.TimeValue),
+                Property.NodeScope,
+                Property.Dynamic
+            )
+        );
+        settingWithFallbackMap.put(
+            SettingType.ByteSizeValue,
+            Setting.byteSizeSetting(
+                "byteSizeSetting",
+                (Setting<ByteSizeValue>) settingMap.get(SettingType.ByteSizeValue),
+                Property.NodeScope,
+                Property.Dynamic
+            )
+        );
+        // No fallback for versionSetting
+
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testBooleanSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Boolean));
+        assertEquals(SettingType.Boolean, ws.getType());
+        Setting<Boolean> setting = (Setting<Boolean>) ws.getSetting();
+        assertEquals("boolSettingBase", setting.getKey());
+        assertFalse(setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.Boolean));
+        assertEquals(SettingType.Boolean, wsfb.getType());
+        setting = (Setting<Boolean>) wsfb.getSetting();
+        assertEquals("boolSetting", setting.getKey());
+        assertFalse(setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Boolean, wsIn.getType());
+                setting = (Setting<Boolean>) wsIn.getSetting();
+                assertEquals("boolSetting", setting.getKey());
+                assertFalse(setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testIntegerSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Integer));
+        assertEquals(SettingType.Integer, ws.getType());
+        Setting<Integer> setting = (Setting<Integer>) ws.getSetting();
+        assertEquals("intSettingBase", setting.getKey());
+        assertEquals(6, (int) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.Integer));
+        assertEquals(SettingType.Integer, wsfb.getType());
+        setting = (Setting<Integer>) wsfb.getSetting();
+        assertEquals("intSetting", setting.getKey());
+        assertEquals(6, (int) setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Integer, wsIn.getType());
+                setting = (Setting<Integer>) wsIn.getSetting();
+                assertEquals("intSetting", setting.getKey());
+                assertEquals(6, (int) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testLongSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Long));
+        assertEquals(SettingType.Long, ws.getType());
+        Setting<Long> setting = (Setting<Long>) ws.getSetting();
+        assertEquals("longSettingBase", setting.getKey());
+        assertEquals(42L, (long) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.Long));
+        assertEquals(SettingType.Long, wsfb.getType());
+        setting = (Setting<Long>) wsfb.getSetting();
+        assertEquals("longSetting", setting.getKey());
+        assertEquals(42L, (long) setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Long, wsIn.getType());
+                setting = (Setting<Long>) wsIn.getSetting();
+                assertEquals("longSetting", setting.getKey());
+                assertEquals(42L, (long) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testFloatSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Float));
+        assertEquals(SettingType.Float, ws.getType());
+        Setting<Float> setting = (Setting<Float>) ws.getSetting();
+        assertEquals("floatSettingBase", setting.getKey());
+        assertEquals(6.2f, (float) setting.getDefault(Settings.EMPTY), Float.MIN_NORMAL);
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.Float));
+        assertEquals(SettingType.Float, wsfb.getType());
+        setting = (Setting<Float>) wsfb.getSetting();
+        assertEquals("floatSetting", setting.getKey());
+        assertEquals(6.2f, (float) setting.getDefault(Settings.EMPTY), Float.MIN_NORMAL);
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Float, wsIn.getType());
+                setting = (Setting<Float>) wsIn.getSetting();
+                assertEquals("floatSetting", setting.getKey());
+                assertEquals(6.2f, (Float) setting.getDefault(Settings.EMPTY), Float.MIN_NORMAL);
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testDoubleSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Double));
+        assertEquals(SettingType.Double, ws.getType());
+        Setting<Double> setting = (Setting<Double>) ws.getSetting();
+        assertEquals("doubleSettingBase", setting.getKey());
+        assertEquals(42.2d, (double) setting.getDefault(Settings.EMPTY), Double.MIN_NORMAL);
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.Double));
+        assertEquals(SettingType.Double, wsfb.getType());
+        setting = (Setting<Double>) wsfb.getSetting();
+        assertEquals("doubleSetting", setting.getKey());
+        assertEquals(42.2d, (double) setting.getDefault(Settings.EMPTY), Double.MIN_NORMAL);
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Double, wsIn.getType());
+                setting = (Setting<Double>) wsIn.getSetting();
+                assertEquals("doubleSetting", setting.getKey());
+                assertEquals(42.2d, (double) setting.getDefault(Settings.EMPTY), Double.MIN_NORMAL);
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testStringSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.String));
+        assertEquals(SettingType.String, ws.getType());
+        Setting<String> setting = (Setting<String>) ws.getSetting();
+        assertEquals("simpleStringBase", setting.getKey());
+        assertEquals("foo", (String) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.String));
+        assertEquals(SettingType.String, wsfb.getType());
+        setting = (Setting<String>) wsfb.getSetting();
+        assertEquals("simpleString", setting.getKey());
+        assertEquals("foo", (String) setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.String, wsIn.getType());
+                setting = (Setting<String>) wsIn.getSetting();
+                assertEquals("simpleString", setting.getKey());
+                assertEquals("foo", (String) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testTimeValueSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.TimeValue));
+        assertEquals(SettingType.TimeValue, ws.getType());
+        Setting<TimeValue> setting = (Setting<TimeValue>) ws.getSetting();
+        assertEquals("timeSettingBase", setting.getKey());
+        assertEquals(new TimeValue(5, TimeUnit.MILLISECONDS), (TimeValue) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.TimeValue));
+        assertEquals(SettingType.TimeValue, wsfb.getType());
+        setting = (Setting<TimeValue>) wsfb.getSetting();
+        assertEquals("timeSetting", setting.getKey());
+        assertEquals(new TimeValue(5, TimeUnit.MILLISECONDS), (TimeValue) setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.TimeValue, wsIn.getType());
+                setting = (Setting<TimeValue>) wsIn.getSetting();
+                assertEquals("timeSetting", setting.getKey());
+                assertEquals(new TimeValue(5, TimeUnit.MILLISECONDS), (TimeValue) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testByteSizeValueSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.ByteSizeValue));
+        assertEquals(SettingType.ByteSizeValue, ws.getType());
+        Setting<ByteSizeValue> setting = (Setting<ByteSizeValue>) ws.getSetting();
+        assertEquals("byteSizeSettingBase", setting.getKey());
+        assertEquals(new ByteSizeValue(10, ByteSizeUnit.KB), (ByteSizeValue) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        WriteableSetting wsfb = new WriteableSetting(settingWithFallbackMap.get(SettingType.ByteSizeValue));
+        assertEquals(SettingType.ByteSizeValue, wsfb.getType());
+        setting = (Setting<ByteSizeValue>) wsfb.getSetting();
+        assertEquals("byteSizeSetting", setting.getKey());
+        assertEquals(new ByteSizeValue(10, ByteSizeUnit.KB), (ByteSizeValue) setting.getDefault(Settings.EMPTY));
+        props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            wsfb.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.ByteSizeValue, wsIn.getType());
+                setting = (Setting<ByteSizeValue>) wsIn.getSetting();
+                assertEquals("byteSizeSetting", setting.getKey());
+                assertEquals(new ByteSizeValue(10, ByteSizeUnit.KB), (ByteSizeValue) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testVersionSetting() throws IOException {
+        WriteableSetting ws = new WriteableSetting(settingMap.get(SettingType.Version));
+        assertEquals(SettingType.Version, ws.getType());
+        Setting<Version> setting = (Setting<Version>) ws.getSetting();
+        assertEquals("versionSettingBase", setting.getKey());
+        assertEquals(Version.CURRENT, (Version) setting.getDefault(Settings.EMPTY));
+        EnumSet<Property> props = setting.getProperties();
+        assertEquals(2, props.size());
+        assertTrue(props.contains(Property.NodeScope));
+        assertTrue(props.contains(Property.Dynamic));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            ws.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                WriteableSetting wsIn = new WriteableSetting(in);
+
+                assertEquals(SettingType.Version, wsIn.getType());
+                setting = (Setting<Version>) wsIn.getSetting();
+                assertEquals("versionSettingBase", setting.getKey());
+                assertEquals(Version.CURRENT, (Version) setting.getDefault(Settings.EMPTY));
+                props = setting.getProperties();
+                assertEquals(2, props.size());
+                assertTrue(props.contains(Property.NodeScope));
+                assertTrue(props.contains(Property.Dynamic));
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/time/DateFormattersTests.java b/server/src/test/java/org/opensearch/common/time/DateFormattersTests.java
index 1e57f9fe88d9c..681daf1755890 100644
--- a/server/src/test/java/org/opensearch/common/time/DateFormattersTests.java
+++ b/server/src/test/java/org/opensearch/common/time/DateFormattersTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.common.time;
 
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.common.joda.Joda;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -56,11 +55,6 @@
 public class DateFormattersTests extends OpenSearchTestCase {
 
     public void testWeekBasedDates() {
-        assumeFalse(
-            "won't work in jdk8 " + "because SPI mechanism is not looking at classpath - needs ISOCalendarDataProvider in jre's ext/libs",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
-
         // as per WeekFields.ISO first week starts on Monday and has minimum 4 days
         DateFormatter dateFormatter = DateFormatters.forPattern("YYYY-ww");
 
diff --git a/server/src/test/java/org/opensearch/common/time/DateUtilsTests.java b/server/src/test/java/org/opensearch/common/time/DateUtilsTests.java
index 95786a130106d..d9662d1de9e0c 100644
--- a/server/src/test/java/org/opensearch/common/time/DateUtilsTests.java
+++ b/server/src/test/java/org/opensearch/common/time/DateUtilsTests.java
@@ -58,7 +58,7 @@
 import static org.hamcrest.Matchers.is;
 
 public class DateUtilsTests extends OpenSearchTestCase {
-    private static final Set<String> IGNORE = new HashSet<>(Arrays.asList("Pacific/Enderbury", "Pacific/Kanton", "Pacific/Niue"));
+    private static final Set<String> IGNORE = new HashSet<>(Arrays.asList("America/Ciudad_Juarez"));
 
     public void testTimezoneIds() {
         assertNull(DateUtils.dateTimeZoneToZoneId(null));
diff --git a/server/src/test/java/org/opensearch/common/time/JavaDateMathParserTests.java b/server/src/test/java/org/opensearch/common/time/JavaDateMathParserTests.java
index a26a3a298b360..a5c7aa00d7cad 100644
--- a/server/src/test/java/org/opensearch/common/time/JavaDateMathParserTests.java
+++ b/server/src/test/java/org/opensearch/common/time/JavaDateMathParserTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.common.time;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.time.Instant;
@@ -111,11 +110,6 @@ public void testOverridingLocaleOrZoneAndCompositeRoundUpParser() {
     }
 
     public void testWeekDates() {
-        assumeFalse(
-            "won't work in jdk8 " + "because SPI mechanism is not looking at classpath - needs ISOCalendarDataProvider in jre's ext/libs",
-            JavaVersion.current().equals(JavaVersion.parse("8"))
-        );
-
         DateFormatter formatter = DateFormatter.forPattern("YYYY-ww");
         assertDateMathEquals(formatter.toDateMathParser(), "2016-01", "2016-01-04T23:59:59.999Z", 0, true, ZoneOffset.UTC);
 
@@ -137,6 +131,16 @@ public void testBasicDates() {
         assertDateMathEquals("2014-05-30T20:21:35.123", "2014-05-30T20:21:35.123");
     }
 
+    public void testDayOfYearWithMissingFields() {
+        DateFormatter formatter = DateFormatter.forPattern("yyyy[-DDD'T'HH:mm:ss.SSS]");
+        assertDateMathEquals(formatter.toDateMathParser(), "2022", "2022-01-01T23:59:59.999Z", 0, true, ZoneOffset.UTC);
+    }
+
+    public void testDayOfYear() {
+        DateFormatter formatter = DateFormatter.forPattern("yyyy[-DDD'T'HH:mm:ss.SSS]");
+        assertDateMathEquals(formatter.toDateMathParser(), "2022-104T14:08:30.293", "2022-04-14T14:08:30.293", 0, true, ZoneOffset.UTC);
+    }
+
     public void testRoundingDoesNotAffectExactDate() {
         assertDateMathEquals("2014-11-12T22:55:00.000Z", "2014-11-12T22:55:00.000Z", 0, true, null);
         assertDateMathEquals("2014-11-12T22:55:00.000Z", "2014-11-12T22:55:00.000Z", 0, false, null);
diff --git a/server/src/test/java/org/opensearch/common/transport/BoundTransportAddressTests.java b/server/src/test/java/org/opensearch/common/transport/BoundTransportAddressTests.java
index 9a7b6c63043cc..dae16d805efbf 100644
--- a/server/src/test/java/org/opensearch/common/transport/BoundTransportAddressTests.java
+++ b/server/src/test/java/org/opensearch/common/transport/BoundTransportAddressTests.java
@@ -33,7 +33,9 @@
 package org.opensearch.common.transport;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.net.InetAddress;
diff --git a/server/src/test/java/org/opensearch/common/unit/DistanceUnitTests.java b/server/src/test/java/org/opensearch/common/unit/DistanceUnitTests.java
index 95fc7f6f7a594..c2dafa82a8699 100644
--- a/server/src/test/java/org/opensearch/common/unit/DistanceUnitTests.java
+++ b/server/src/test/java/org/opensearch/common/unit/DistanceUnitTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.unit;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.closeTo;
diff --git a/server/src/test/java/org/opensearch/common/unit/FuzzinessTests.java b/server/src/test/java/org/opensearch/common/unit/FuzzinessTests.java
index 71e2b322c2307..4853cec8d6735 100644
--- a/server/src/test/java/org/opensearch/common/unit/FuzzinessTests.java
+++ b/server/src/test/java/org/opensearch/common/unit/FuzzinessTests.java
@@ -31,10 +31,11 @@
 
 package org.opensearch.common.unit;
 
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -138,6 +139,26 @@ public void testParseFromXContent() throws IOException {
 
     }
 
+    public void testFuzzinessValidationWithStrings() throws IOException {
+        String[] invalidStrings = new String[] { "+++", "asdfghjkl", "2k23", "-1.0", "-100" };
+        XContentBuilder json = jsonBuilder().startObject().field(Fuzziness.X_FIELD_NAME, randomFrom(invalidStrings)).endObject();
+        try (XContentParser parser = createParser(json)) {
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.START_OBJECT));
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.FIELD_NAME));
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.VALUE_STRING));
+            IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> Fuzziness.parse(parser));
+            assertTrue(e.getMessage().startsWith("Invalid fuzziness value:"));
+        }
+        json = jsonBuilder().startObject().field(Fuzziness.X_FIELD_NAME, "AUTO:").endObject();
+        try (XContentParser parser = createParser(json)) {
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.START_OBJECT));
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.FIELD_NAME));
+            assertThat(parser.nextToken(), equalTo(XContentParser.Token.VALUE_STRING));
+            OpenSearchParseException e = expectThrows(OpenSearchParseException.class, () -> Fuzziness.parse(parser));
+            assertTrue(e.getMessage().startsWith("failed to find low and high distance values"));
+        }
+    }
+
     public void testAuto() {
         assertThat(Fuzziness.AUTO.asFloat(), equalTo(1f));
     }
@@ -174,6 +195,12 @@ public void testSerializationCustomAuto() throws IOException {
         assertNotSame(original, deserializedFuzziness);
         assertEquals(original, deserializedFuzziness);
         assertEquals(original.asString(), deserializedFuzziness.asString());
+
+        original = Fuzziness.customAuto(4, 7);
+        deserializedFuzziness = doSerializeRoundtrip(original);
+        assertNotSame(original, deserializedFuzziness);
+        assertEquals(original, deserializedFuzziness);
+        assertEquals(original.asString(), deserializedFuzziness.asString());
     }
 
     private static Fuzziness doSerializeRoundtrip(Fuzziness in) throws IOException {
@@ -205,5 +232,11 @@ public void testAsDistanceString() {
         assertEquals(1, fuzziness.asDistance("abcdef"));
         assertEquals(2, fuzziness.asDistance("abcdefg"));
 
+        fuzziness = Fuzziness.customAuto(5, 7);
+        assertEquals(0, fuzziness.asDistance(""));
+        assertEquals(0, fuzziness.asDistance("abcd"));
+        assertEquals(1, fuzziness.asDistance("abcde"));
+        assertEquals(1, fuzziness.asDistance("abcdef"));
+        assertEquals(2, fuzziness.asDistance("abcdefg"));
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/util/BigArraysTests.java b/server/src/test/java/org/opensearch/common/util/BigArraysTests.java
index 909995a2bc19c..a12967f257610 100644
--- a/server/src/test/java/org/opensearch/common/util/BigArraysTests.java
+++ b/server/src/test/java/org/opensearch/common/util/BigArraysTests.java
@@ -33,13 +33,15 @@
 package org.opensearch.common.util;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.util.BigArray;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/common/util/BinarySearcherTests.java b/server/src/test/java/org/opensearch/common/util/BinarySearcherTests.java
index fc441d63fc0b3..b1b29097d56bf 100644
--- a/server/src/test/java/org/opensearch/common/util/BinarySearcherTests.java
+++ b/server/src/test/java/org/opensearch/common/util/BinarySearcherTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/common/util/BitArrayTests.java b/server/src/test/java/org/opensearch/common/util/BitArrayTests.java
index 16e89b81c695c..e88e2b20c6155 100644
--- a/server/src/test/java/org/opensearch/common/util/BitArrayTests.java
+++ b/server/src/test/java/org/opensearch/common/util/BitArrayTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.common.util;
 
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/common/util/BytesRefHashTests.java b/server/src/test/java/org/opensearch/common/util/BytesRefHashTests.java
index 1859a7d4a8f9d..adcec8f07f702 100644
--- a/server/src/test/java/org/opensearch/common/util/BytesRefHashTests.java
+++ b/server/src/test/java/org/opensearch/common/util/BytesRefHashTests.java
@@ -32,14 +32,12 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.ObjectLongHashMap;
-import com.carrotsearch.hppc.ObjectLongMap;
-import com.carrotsearch.hppc.cursors.ObjectLongCursor;
+import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.tests.util.TestUtil;
+import org.opensearch.common.hash.T1ha1;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashMap;
@@ -47,6 +45,7 @@
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.stream.Stream;
 
 public class BytesRefHashTests extends OpenSearchTestCase {
 
@@ -60,9 +59,13 @@ private void newHash() {
         if (hash != null) {
             hash.close();
         }
-        // Test high load factors to make sure that collision resolution works fine
-        final float maxLoadFactor = 0.6f + randomFloat() * 0.39f;
-        hash = new BytesRefHash(randomIntBetween(0, 100), maxLoadFactor, randomBigArrays());
+        long seed = randomLong();
+        hash = new BytesRefHash(
+            randomIntBetween(1, 100),      // random capacity
+            0.6f + randomFloat() * 0.39f,  // random load factor to verify collision resolution
+            key -> T1ha1.hash(key.bytes, key.offset, key.length, seed),
+            randomBigArrays()
+        );
     }
 
     @Override
@@ -71,39 +74,34 @@ public void setUp() throws Exception {
         newHash();
     }
 
-    public void testDuel() {
-        final int len = randomIntBetween(1, 100000);
-        final BytesRef[] values = new BytesRef[len];
-        for (int i = 0; i < values.length; ++i) {
-            values[i] = new BytesRef(randomAlphaOfLength(5));
-        }
-        final ObjectLongMap<BytesRef> valueToId = new ObjectLongHashMap<>();
-        final BytesRef[] idToValue = new BytesRef[values.length];
-        final int iters = randomInt(1000000);
-        for (int i = 0; i < iters; ++i) {
-            final BytesRef value = randomFrom(values);
-            if (valueToId.containsKey(value)) {
-                assertEquals(-1 - valueToId.get(value), hash.add(value, value.hashCode()));
+    public void testFuzzy() {
+        Map<BytesRef, Long> reference = new HashMap<>();
+        BytesRef[] keys = Stream.generate(() -> new BytesRef(randomAlphaOfLength(20)))
+            .limit(randomIntBetween(1000, 2000))
+            .toArray(BytesRef[]::new);
+
+        // Verify the behaviour of "add" and "find".
+        for (int i = 0; i < keys.length * 10; i++) {
+            BytesRef key = keys[i % keys.length];
+            if (reference.containsKey(key)) {
+                long expectedOrdinal = reference.get(key);
+                assertEquals(-1 - expectedOrdinal, hash.add(key));
+                assertEquals(expectedOrdinal, hash.find(key));
             } else {
-                assertEquals(valueToId.size(), hash.add(value, value.hashCode()));
-                idToValue[valueToId.size()] = value;
-                valueToId.put(value, valueToId.size());
+                assertEquals(-1, hash.find(key));
+                reference.put(key, (long) reference.size());
+                assertEquals((long) reference.get(key), hash.add(key));
             }
         }
 
-        assertEquals(valueToId.size(), hash.size());
-        for (final ObjectLongCursor<BytesRef> next : valueToId) {
-            assertEquals(next.value, hash.find(next.key, next.key.hashCode()));
+        // Verify the behaviour of "get".
+        BytesRef scratch = new BytesRef();
+        for (Map.Entry<BytesRef, Long> entry : reference.entrySet()) {
+            assertEquals(entry.getKey(), hash.get(entry.getValue(), scratch));
         }
 
-        for (long i = 0; i < hash.capacity(); ++i) {
-            final long id = hash.id(i);
-            BytesRef spare = new BytesRef();
-            if (id >= 0) {
-                hash.get(id, spare);
-                assertEquals(idToValue[(int) id], spare);
-            }
-        }
+        // Verify the behaviour of "size".
+        assertEquals(reference.size(), hash.size());
         hash.close();
     }
 
diff --git a/server/src/test/java/org/opensearch/common/util/CollectionUtilsTests.java b/server/src/test/java/org/opensearch/common/util/CollectionUtilsTests.java
index 381bd1784909d..1c629bd77fe93 100644
--- a/server/src/test/java/org/opensearch/common/util/CollectionUtilsTests.java
+++ b/server/src/test/java/org/opensearch/common/util/CollectionUtilsTests.java
@@ -32,28 +32,22 @@
 
 package org.opensearch.common.util;
 
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.BytesRefArray;
-import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.Counter;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.SortedSet;
-import java.util.TreeSet;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.util.CollectionUtils.eagerPartition;
+import static org.opensearch.core.common.util.CollectionUtils.eagerPartition;
 import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.is;
 
 public class CollectionUtilsTests extends OpenSearchTestCase {
     public void testRotateEmpty() {
@@ -85,65 +79,30 @@ public void testRotate() {
         }
     }
 
-    public void testSortAndDedupByteRefArray() {
-        SortedSet<BytesRef> set = new TreeSet<>();
-        final int numValues = scaledRandomIntBetween(0, 10000);
-        List<BytesRef> tmpList = new ArrayList<>();
-        BytesRefArray array = new BytesRefArray(Counter.newCounter());
-        for (int i = 0; i < numValues; i++) {
-            String s = randomRealisticUnicodeOfCodepointLengthBetween(1, 100);
-            set.add(new BytesRef(s));
-            tmpList.add(new BytesRef(s));
-            array.append(new BytesRef(s));
-        }
-        if (randomBoolean()) {
-            Collections.shuffle(tmpList, random());
-            for (BytesRef ref : tmpList) {
-                array.append(ref);
+    private <T> void assertDeduped(List<T> array, Comparator<T> cmp, int expectedLength) {
+        // test the dedup w/ ArrayLists and LinkedLists
+        List<List<T>> types = List.of(new ArrayList<T>(array), new LinkedList<>(array));
+        for (List<T> clone : types) {
+            // dedup the list
+            CollectionUtils.sortAndDedup(clone, cmp);
+            // verify unique elements
+            for (int i = 0; i < clone.size() - 1; ++i) {
+                assertNotEquals(cmp.compare(clone.get(i), clone.get(i + 1)), 0);
             }
+            assertEquals(expectedLength, clone.size());
         }
-        int[] indices = new int[array.size()];
-        for (int i = 0; i < indices.length; i++) {
-            indices[i] = i;
-        }
-        int numUnique = CollectionUtils.sortAndDedup(array, indices);
-        assertThat(numUnique, equalTo(set.size()));
-        Iterator<BytesRef> iterator = set.iterator();
-
-        BytesRefBuilder spare = new BytesRefBuilder();
-        for (int i = 0; i < numUnique; i++) {
-            assertThat(iterator.hasNext(), is(true));
-            assertThat(array.get(spare, indices[i]), equalTo(iterator.next()));
-        }
-
     }
 
-    public void testSortByteRefArray() {
-        List<BytesRef> values = new ArrayList<>();
-        final int numValues = scaledRandomIntBetween(0, 10000);
-        BytesRefArray array = new BytesRefArray(Counter.newCounter());
-        for (int i = 0; i < numValues; i++) {
-            String s = randomRealisticUnicodeOfCodepointLengthBetween(1, 100);
-            values.add(new BytesRef(s));
-            array.append(new BytesRef(s));
-        }
-        if (randomBoolean()) {
-            Collections.shuffle(values, random());
-        }
-        int[] indices = new int[array.size()];
-        for (int i = 0; i < indices.length; i++) {
-            indices[i] = i;
-        }
-        CollectionUtils.sort(array, indices);
-        Collections.sort(values);
-        Iterator<BytesRef> iterator = values.iterator();
-
-        BytesRefBuilder spare = new BytesRefBuilder();
-        for (int i = 0; i < values.size(); i++) {
-            assertThat(iterator.hasNext(), is(true));
-            assertThat(array.get(spare, indices[i]), equalTo(iterator.next()));
-        }
-
+    public void testSortAndDedup() {
+        // test no elements in a string array
+        assertDeduped(List.<String>of(), Comparator.naturalOrder(), 0);
+        // test no elements in an integer array
+        assertDeduped(List.<Integer>of(), Comparator.naturalOrder(), 0);
+        // test unsorted array
+        assertDeduped(List.of(-1, 0, 2, 1, -1, 19, -1), Comparator.naturalOrder(), 5);
+        // test sorted array
+        assertDeduped(List.of(-1, 0, 1, 2, 19, 19), Comparator.naturalOrder(), 5);
+        // test sorted
     }
 
     public void testEmptyPartition() {
@@ -201,4 +160,11 @@ public void testEnsureNoSelfReferences() {
         }
 
     }
+
+    public void testIsEmpty() {
+        assertTrue(CollectionUtils.isEmpty(new ArrayList<>()));
+        final List<Integer> list = null;
+        assertTrue(CollectionUtils.isEmpty(list));
+        assertFalse(CollectionUtils.isEmpty(Collections.singletonList(5)));
+    }
 }
diff --git a/server/src/test/java/org/opensearch/common/util/CuckooFilterTests.java b/server/src/test/java/org/opensearch/common/util/CuckooFilterTests.java
index 5fa1b61bcf211..bba164c607f0f 100644
--- a/server/src/test/java/org/opensearch/common/util/CuckooFilterTests.java
+++ b/server/src/test/java/org/opensearch/common/util/CuckooFilterTests.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.common.Randomness;
 import org.opensearch.common.hash.MurmurHash3;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/common/util/FeatureFlagTests.java b/server/src/test/java/org/opensearch/common/util/FeatureFlagTests.java
new file mode 100644
index 0000000000000..f175308482b15
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/FeatureFlagTests.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.test.FeatureFlagSetter;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class FeatureFlagTests extends OpenSearchTestCase {
+
+    private final String FLAG_PREFIX = "opensearch.experimental.feature.";
+
+    public void testFeatureFlagSet() {
+        final String testFlag = FLAG_PREFIX + "testFlag";
+        FeatureFlagSetter.set(testFlag);
+        assertNotNull(System.getProperty(testFlag));
+        assertTrue(FeatureFlags.isEnabled(testFlag));
+    }
+
+    public void testMissingFeatureFlag() {
+        final String testFlag = FLAG_PREFIX + "testFlag";
+        assertNull(System.getProperty(testFlag));
+        assertFalse(FeatureFlags.isEnabled(testFlag));
+    }
+
+    public void testNonBooleanFeatureFlag() {
+        String javaVersionProperty = "java.version";
+        assertNotNull(System.getProperty(javaVersionProperty));
+        assertFalse(FeatureFlags.isEnabled(javaVersionProperty));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/LongHashTests.java b/server/src/test/java/org/opensearch/common/util/LongHashTests.java
index aabc3c295e6fa..3716c7ad277b3 100644
--- a/server/src/test/java/org/opensearch/common/util/LongHashTests.java
+++ b/server/src/test/java/org/opensearch/common/util/LongHashTests.java
@@ -32,17 +32,12 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.LongLongHashMap;
-import com.carrotsearch.hppc.LongLongMap;
-import com.carrotsearch.hppc.cursors.LongLongCursor;
-
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 
@@ -74,7 +69,7 @@ public void testDuell() {
         for (int i = 0; i < values.length; ++i) {
             values[i] = randomLong();
         }
-        final LongLongMap valueToId = new LongLongHashMap();
+        final Map<Long, Integer> valueToId = new HashMap<>();
         final long[] idToValue = new long[values.length];
         final int iters = randomInt(1000000);
         for (int i = 0; i < iters; ++i) {
@@ -89,9 +84,8 @@ public void testDuell() {
         }
 
         assertEquals(valueToId.size(), hash.size());
-        for (Iterator<LongLongCursor> iterator = valueToId.iterator(); iterator.hasNext();) {
-            final LongLongCursor next = iterator.next();
-            assertEquals(next.value, hash.find(next.key));
+        for (var iterator : valueToId.entrySet()) {
+            assertEquals(iterator.getValue().longValue(), hash.find(iterator.getKey()));
         }
 
         for (long i = 0; i < hash.capacity(); ++i) {
diff --git a/server/src/test/java/org/opensearch/common/util/LongLongHashTests.java b/server/src/test/java/org/opensearch/common/util/LongLongHashTests.java
index fd0f1b5bad4a7..e0b0182216c27 100644
--- a/server/src/test/java/org/opensearch/common/util/LongLongHashTests.java
+++ b/server/src/test/java/org/opensearch/common/util/LongLongHashTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.common.util;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/common/util/LongObjectHashMapTests.java b/server/src/test/java/org/opensearch/common/util/LongObjectHashMapTests.java
index f99f1f8a9a1d5..dc4743189f4cf 100644
--- a/server/src/test/java/org/opensearch/common/util/LongObjectHashMapTests.java
+++ b/server/src/test/java/org/opensearch/common/util/LongObjectHashMapTests.java
@@ -32,11 +32,13 @@
 
 package org.opensearch.common.util;
 
-import com.carrotsearch.hppc.LongObjectHashMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class LongObjectHashMapTests extends OpenSearchTestCase {
 
     private BigArrays randomBigArrays() {
@@ -44,7 +46,7 @@ private BigArrays randomBigArrays() {
     }
 
     public void testDuel() {
-        final LongObjectHashMap<Object> map1 = new LongObjectHashMap<>();
+        final Map<Long, Object> map1 = new HashMap<>();
         final LongObjectPagedHashMap<Object> map2 = new LongObjectPagedHashMap<>(
             randomInt(42),
             0.6f + randomFloat() * 0.39f,
@@ -66,10 +68,10 @@ public void testDuel() {
                 assertEquals(map1.size(), map2.size());
             }
         }
-        for (int i = 0; i <= maxKey; ++i) {
+        for (long i = 0; i <= maxKey; ++i) {
             assertSame(map1.get(i), map2.get(i));
         }
-        final LongObjectHashMap<Object> copy = new LongObjectHashMap<>();
+        final Map<Long, Object> copy = new HashMap<>();
         for (LongObjectPagedHashMap.Cursor<Object> cursor : map2) {
             copy.put(cursor.key, cursor.value);
         }
diff --git a/server/src/test/java/org/opensearch/common/util/MovingAverageTests.java b/server/src/test/java/org/opensearch/common/util/MovingAverageTests.java
new file mode 100644
index 0000000000000..4f6b0ac4f7c88
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/MovingAverageTests.java
@@ -0,0 +1,89 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class MovingAverageTests extends OpenSearchTestCase {
+
+    public void testMovingAverage() {
+        MovingAverage ma = new MovingAverage(5);
+
+        // No observations
+        assertEquals(0.0, ma.getAverage(), 0.0);
+        assertEquals(0, ma.getCount());
+
+        // Not enough observations
+        ma.record(1);
+        ma.record(2);
+        ma.record(3);
+        assertEquals(2.0, ma.getAverage(), 0.0);
+        assertEquals(3, ma.getCount());
+        assertFalse(ma.isReady());
+
+        // Enough observations
+        ma.record(4);
+        ma.record(5);
+        ma.record(6);
+        assertEquals(4, ma.getAverage(), 0.0);
+        assertEquals(6, ma.getCount());
+        assertTrue(ma.isReady());
+    }
+
+    public void testMovingAverageWithZeroSize() {
+        try {
+            new MovingAverage(0);
+        } catch (IllegalArgumentException e) {
+            assertTrue(e.getMessage().contains("window size must be greater than zero"));
+            return;
+        }
+
+        fail("exception should have been thrown");
+    }
+
+    public void testUpdateMovingAverageWindowSize() {
+        MovingAverage ma = new MovingAverage(5);
+        ma.record(1);
+        ma.record(2);
+        ma.record(3);
+        double avg = ma.getAverage();
+
+        // Test case 1 - Not ready and increasing size
+        MovingAverage newMa = ma.copyWithSize(10);
+        assertEquals(avg, newMa.getAverage(), 0.0d);
+
+        // Test case 2 - Not ready and decreasing size
+        newMa = ma.copyWithSize(2);
+        assertEquals(2.5, newMa.getAverage(), 0.0d);
+
+        // Test case 3 - Ready and increasing size
+        ma.record(4);
+        ma.record(5);
+        ma.record(6);
+        assertEquals(4.0, ma.getAverage(), 0.0d);
+
+        newMa = ma.copyWithSize(10);
+        assertEquals(ma.getAverage(), newMa.getAverage(), 0.0d);
+
+        // Test case 4 - Ready and decreasing size
+        newMa = ma.copyWithSize(3);
+        assertEquals(5.0, newMa.getAverage(), 0.0d);
+
+        // Test case 5 - Ready, array overwritten and increasing size
+        for (int i = 7; i < 20; i++) {
+            ma.record(i);
+        }
+        newMa = ma.copyWithSize(6);
+        assertEquals(ma.getAverage(), newMa.getAverage(), 0.0d);
+
+        // Test case 6 - Ready, array overwritten and decreasing size
+        newMa = ma.copyWithSize(3);
+        assertEquals(18.0, newMa.getAverage(), 0.0d);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/ReorganizingLongHashTests.java b/server/src/test/java/org/opensearch/common/util/ReorganizingLongHashTests.java
new file mode 100644
index 0000000000000..259eab6c624bd
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/ReorganizingLongHashTests.java
@@ -0,0 +1,146 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ReorganizingLongHashTests extends OpenSearchTestCase {
+
+    public void testFuzzy() {
+        Map<Long, Long> reference = new HashMap<>();
+
+        try (
+            ReorganizingLongHash h = new ReorganizingLongHash(
+                randomIntBetween(1, 100),      // random capacity
+                0.6f + randomFloat() * 0.39f,  // random load factor to verify collision resolution
+                BigArrays.NON_RECYCLING_INSTANCE
+            )
+        ) {
+            // Verify the behaviour of "add" and "find".
+            for (int i = 0; i < (1 << 20); i++) {
+                long key = randomLong() % (1 << 12);  // roughly ~4% unique keys
+                if (reference.containsKey(key)) {
+                    long expectedOrdinal = reference.get(key);
+                    assertEquals(-1 - expectedOrdinal, h.add(key));
+                    assertEquals(expectedOrdinal, h.find(key));
+                } else {
+                    assertEquals(-1, h.find(key));
+                    reference.put(key, (long) reference.size());
+                    assertEquals((long) reference.get(key), h.add(key));
+                }
+            }
+
+            // Verify the behaviour of "get".
+            for (Map.Entry<Long, Long> entry : reference.entrySet()) {
+                assertEquals((long) entry.getKey(), h.get(entry.getValue()));
+            }
+
+            // Verify the behaviour of "size".
+            assertEquals(reference.size(), h.size());
+
+            // Verify the calculation of PSLs.
+            final long capacity = h.getTable().size();
+            final long mask = capacity - 1;
+            for (long idx = 0; idx < h.getTable().size(); idx++) {
+                final long value = h.getTable().get(idx);
+                if (value != -1) {
+                    final long homeIdx = h.hash(h.get((int) value)) & mask;
+                    assertEquals((capacity + idx - homeIdx) & mask, value >>> 48);
+                }
+            }
+        }
+    }
+
+    public void testRearrangement() {
+        try (ReorganizingLongHash h = new ReorganizingLongHash(4, 0.6f, BigArrays.NON_RECYCLING_INSTANCE) {
+            /**
+             * Overriding with an "identity" hash function to make it easier to reason about the placement
+             * of values in the hash table. The backing array of the hash table will have a size (8),
+             * i.e. nextPowerOfTwo(initialCapacity/loadFactor), so the bitmask will be (7).
+             * The ideal home slot of a key can then be defined as: (hash(key) & mask) = (key & 7).
+             */
+            @Override
+            long hash(long key) {
+                return key;
+            }
+        }) {
+            /*
+             * Add key=0, hash=0, home_slot=0
+             *
+             * Before: empty slot.
+             *   ▼
+             * [ _ _ _ _ _ _ _ _ ]
+             *
+             * After: inserted [ordinal=0, psl=0] at the empty slot.
+             * [ 0 _ _ _ _ _ _ _ ]
+             */
+            h.add(0);
+            assertEquals(encodeValue(0, 0, 0), h.getTable().get(0));
+
+            /*
+             * Add key=8, hash=8, home_slot=0
+             *
+             * Before: occupied slot.
+             *   ▼
+             * [ 0 _ _ _ _ _ _ _ ]
+             *
+             * After: inserted [ordinal=1, psl=0] at the existing slot, displaced [ordinal=0, psl=0],
+             *        and re-inserted it at the next empty slot as [ordinal=0, psl=1].
+             * [ 1 0 _ _ _ _ _ _ ]
+             */
+            h.add(8);
+            assertEquals(encodeValue(0, 0, 1), h.getTable().get(0));
+            assertEquals(encodeValue(1, 0, 0), h.getTable().get(1));
+
+            /*
+             * Add key=1, hash=1, home_slot=1
+             *
+             * Before: occupied slot.
+             *     ▼
+             * [ 1 0 _ _ _ _ _ _ ]
+             *
+             * After: inserted [ordinal=2, psl=0] at the existing slot, displaced [ordinal=0, psl=1],
+             *        and re-inserted it at the next empty slot as [ordinal=0, psl=2].
+             * [ 1 2 0 _ _ _ _ _ ]
+             */
+            h.add(1);
+            assertEquals(encodeValue(0, 0, 1), h.getTable().get(0));
+            assertEquals(encodeValue(0, 0, 2), h.getTable().get(1));
+            assertEquals(encodeValue(2, 0, 0), h.getTable().get(2));
+
+            /*
+             * Add key=16, hash=16, home_slot=0
+             *
+             * Before: occupied slot.
+             *   ▼
+             * [ 1 2 0 _ _ _ _ _ ]
+             *
+             * After: inserted [ordinal=3, psl=0] at the existing slot, displaced [ordinal=1, psl=0]
+             *        and re-inserted it at the next best slot. Repeated this for other displaced values
+             *        until everything found an empty slot.
+             * [ 3 1 0 2 _ _ _ _ ]
+             */
+            h.add(16);
+            assertEquals(encodeValue(0, 0, 3), h.getTable().get(0));
+            assertEquals(encodeValue(1, 0, 1), h.getTable().get(1));
+            assertEquals(encodeValue(2, 0, 0), h.getTable().get(2));
+            assertEquals(encodeValue(2, 0, 2), h.getTable().get(3));
+        }
+    }
+
+    private static long encodeValue(long psl, long fingerprint, long ordinal) {
+        assert psl < (1L << 15);
+        assert fingerprint < (1L << 16);
+        assert ordinal < (1L << 32);
+        return (psl << 48) | (fingerprint << 32) | ordinal;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/SetBackedScalingCuckooFilterTests.java b/server/src/test/java/org/opensearch/common/util/SetBackedScalingCuckooFilterTests.java
index b1c1aefa9c162..94b758a82f433 100644
--- a/server/src/test/java/org/opensearch/common/util/SetBackedScalingCuckooFilterTests.java
+++ b/server/src/test/java/org/opensearch/common/util/SetBackedScalingCuckooFilterTests.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.common.Randomness;
 import org.opensearch.common.hash.MurmurHash3;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/util/StreakTests.java b/server/src/test/java/org/opensearch/common/util/StreakTests.java
new file mode 100644
index 0000000000000..682a28d3a3a8b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/StreakTests.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class StreakTests extends OpenSearchTestCase {
+
+    public void testStreak() {
+        Streak streak = new Streak();
+
+        // Streak starts with zero.
+        assertEquals(0, streak.length());
+
+        // Streak increases on successive successful events.
+        streak.record(true);
+        assertEquals(1, streak.length());
+        streak.record(true);
+        assertEquals(2, streak.length());
+        streak.record(true);
+        assertEquals(3, streak.length());
+
+        // Streak resets to zero after an unsuccessful event.
+        streak.record(false);
+        assertEquals(0, streak.length());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/TokenBucketTests.java b/server/src/test/java/org/opensearch/common/util/TokenBucketTests.java
new file mode 100644
index 0000000000000..a52e97cdd835c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/TokenBucketTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.LongSupplier;
+
+public class TokenBucketTests extends OpenSearchTestCase {
+
+    public void testTokenBucket() {
+        AtomicLong mockTimeNanos = new AtomicLong();
+        LongSupplier mockTimeNanosSupplier = mockTimeNanos::get;
+
+        // Token bucket that refills at 2 tokens/second and allows short bursts up to 3 operations.
+        TokenBucket tokenBucket = new TokenBucket(mockTimeNanosSupplier, 2.0 / TimeUnit.SECONDS.toNanos(1), 3);
+
+        // Three operations succeed, fourth fails.
+        assertTrue(tokenBucket.request());
+        assertTrue(tokenBucket.request());
+        assertTrue(tokenBucket.request());
+        assertFalse(tokenBucket.request());
+
+        // Clock moves ahead by one second. Two operations succeed, third fails.
+        mockTimeNanos.addAndGet(TimeUnit.SECONDS.toNanos(1));
+        assertTrue(tokenBucket.request());
+        assertTrue(tokenBucket.request());
+        assertFalse(tokenBucket.request());
+
+        // Clock moves ahead by half a second. One operation succeeds, second fails.
+        mockTimeNanos.addAndGet(TimeUnit.MILLISECONDS.toNanos(500));
+        assertTrue(tokenBucket.request());
+        assertFalse(tokenBucket.request());
+
+        // Clock moves ahead by many seconds, but the token bucket should be capped at the 'burst' capacity.
+        mockTimeNanos.addAndGet(TimeUnit.SECONDS.toNanos(10));
+        assertTrue(tokenBucket.request());
+        assertTrue(tokenBucket.request());
+        assertTrue(tokenBucket.request());
+        assertFalse(tokenBucket.request());
+
+        // Ability to request fractional tokens.
+        mockTimeNanos.addAndGet(TimeUnit.MILLISECONDS.toNanos(250));
+        assertFalse(tokenBucket.request(1.0));
+        assertTrue(tokenBucket.request(0.5));
+    }
+
+    public void testTokenBucketWithInvalidRate() {
+        try {
+            new TokenBucket(System::nanoTime, -1, 2);
+        } catch (IllegalArgumentException e) {
+            assertTrue(e.getMessage().contains("rate must be greater than zero"));
+            return;
+        }
+
+        fail("exception should have been thrown");
+    }
+
+    public void testTokenBucketWithInvalidBurst() {
+        try {
+            new TokenBucket(System::nanoTime, 1, 0);
+        } catch (IllegalArgumentException e) {
+            assertTrue(e.getMessage().contains("burst must be greater than zero"));
+            return;
+        }
+
+        fail("exception should have been thrown");
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractAsyncTaskTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractAsyncTaskTests.java
index b62b830de5036..e56a1793c06e6 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractAsyncTaskTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractAsyncTaskTests.java
@@ -33,7 +33,7 @@
 
 import org.opensearch.common.Randomness;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnableTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnableTests.java
index d771fdbef38d6..056cfb301198d 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnableTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractLifecycleRunnableTests.java
@@ -33,12 +33,13 @@
 
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.SuppressLoggerChecks;
-import org.opensearch.common.component.Lifecycle;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.InOrder;
 
 import java.util.concurrent.Callable;
 
+import org.mockito.InOrder;
+
 import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractRunnableTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractRunnableTests.java
index 286b90f391b3c..d288ec7726e0a 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/AbstractRunnableTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/AbstractRunnableTests.java
@@ -33,10 +33,10 @@
 
 import org.opensearch.test.OpenSearchTestCase;
 
-import org.mockito.InOrder;
-
 import java.util.concurrent.Callable;
 
+import org.mockito.InOrder;
+
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessorTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessorTests.java
new file mode 100644
index 0000000000000..29d7104370049
--- /dev/null
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/BufferedAsyncIOProcessorTests.java
@@ -0,0 +1,256 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.util.concurrent;
+
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import static java.lang.Thread.sleep;
+
+public class BufferedAsyncIOProcessorTests extends OpenSearchTestCase {
+
+    private ThreadPool threadpool;
+    private ThreadContext threadContext;
+
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        threadpool = new TestThreadPool("buffered-async-io");
+        threadContext = new ThreadContext(Settings.EMPTY);
+    }
+
+    @After
+    public void cleanup() {
+        terminate(threadpool);
+    }
+
+    public void testConsumerCanThrowExceptions() {
+        AtomicInteger received = new AtomicInteger(0);
+        AtomicInteger notified = new AtomicInteger(0);
+
+        AsyncIOProcessor<Object> processor = new BufferedAsyncIOProcessor<>(
+            logger,
+            scaledRandomIntBetween(1, 2024),
+            threadContext,
+            threadpool,
+            () -> TimeValue.timeValueMillis(50)
+        ) {
+            @Override
+            protected void write(List<Tuple<Object, Consumer<Exception>>> candidates) throws IOException {
+                received.addAndGet(candidates.size());
+            }
+
+            @Override
+            protected String getBufferProcessThreadPoolName() {
+                return ThreadPool.Names.TRANSLOG_SYNC;
+            }
+        };
+        processor.put(new Object(), (e) -> {
+            notified.incrementAndGet();
+            throw new RuntimeException();
+        });
+        processor.put(new Object(), (e) -> {
+            notified.incrementAndGet();
+            throw new RuntimeException();
+        });
+        try {
+            sleep(200); // Give the processor few chances to run
+        } catch (InterruptedException e) {
+            logger.error("Error while trying to sleep", e);
+        }
+        assertEquals(2, notified.get());
+        assertEquals(2, received.get());
+    }
+
+    public void testPreserveThreadContext() throws InterruptedException {
+        final int threadCount = randomIntBetween(2, 10);
+        final String testHeader = "test-header";
+
+        AtomicInteger received = new AtomicInteger(0);
+        AtomicInteger notified = new AtomicInteger(0);
+
+        CountDownLatch processed = new CountDownLatch(threadCount);
+        AsyncIOProcessor<Object> processor = new BufferedAsyncIOProcessor<>(
+            logger,
+            scaledRandomIntBetween(1, 2024),
+            threadContext,
+            threadpool,
+            () -> TimeValue.timeValueMillis(100)
+        ) {
+            @Override
+            protected void write(List<Tuple<Object, Consumer<Exception>>> candidates) throws IOException {
+                received.addAndGet(candidates.size());
+            }
+
+            @Override
+            protected String getBufferProcessThreadPoolName() {
+                return ThreadPool.Names.TRANSLOG_SYNC;
+            }
+        };
+
+        // all threads should be non-blocking.
+        List<Thread> threads = IntStream.range(0, threadCount).mapToObj(i -> new Thread(getTestName() + "_" + i) {
+            private final String response = randomAlphaOfLength(10);
+
+            {
+                setDaemon(true);
+            }
+
+            @Override
+            public void run() {
+                threadContext.addResponseHeader(testHeader, response);
+                processor.put(new Object(), (e) -> {
+                    final Map<String, List<String>> expected = Collections.singletonMap(testHeader, Collections.singletonList(response));
+                    assertEquals(expected, threadContext.getResponseHeaders());
+                    notified.incrementAndGet();
+                    processed.countDown();
+                });
+            }
+        }).collect(Collectors.toList());
+        threads.forEach(Thread::start);
+        threads.forEach(t -> {
+            try {
+                t.join(20000);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        assertTrue(processed.await(1, TimeUnit.SECONDS));
+
+        assertEquals(threadCount, notified.get());
+        assertEquals(threadCount, received.get());
+        threads.forEach(t -> assertFalse(t.isAlive()));
+    }
+
+    public void testSlowConsumer() {
+        AtomicInteger received = new AtomicInteger(0);
+        AtomicInteger notified = new AtomicInteger(0);
+
+        AsyncIOProcessor<Object> processor = new BufferedAsyncIOProcessor<>(
+            logger,
+            scaledRandomIntBetween(1, 2024),
+            threadContext,
+            threadpool,
+            () -> TimeValue.timeValueMillis(100)
+        ) {
+            @Override
+            protected void write(List<Tuple<Object, Consumer<Exception>>> candidates) throws IOException {
+                received.addAndGet(candidates.size());
+            }
+
+            @Override
+            protected String getBufferProcessThreadPoolName() {
+                return ThreadPool.Names.TRANSLOG_SYNC;
+            }
+        };
+
+        int threadCount = randomIntBetween(2, 10);
+        Semaphore serializePutSemaphore = new Semaphore(1);
+        CountDownLatch allDone = new CountDownLatch(threadCount);
+        List<Thread> threads = IntStream.range(0, threadCount).mapToObj(i -> new Thread(getTestName() + "_" + i) {
+            {
+                setDaemon(true);
+            }
+
+            @Override
+            public void run() {
+                try {
+                    assertTrue(serializePutSemaphore.tryAcquire(10, TimeUnit.SECONDS));
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+                processor.put(new Object(), (e) -> {
+                    serializePutSemaphore.release();
+                    notified.incrementAndGet();
+                    allDone.countDown();
+                });
+            }
+        }).collect(Collectors.toList());
+        threads.forEach(Thread::start);
+        threads.forEach(t -> {
+            try {
+                t.join(20000);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        try {
+            assertTrue(allDone.await(20000, TimeUnit.MILLISECONDS));
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+        assertEquals(threadCount, notified.get());
+        assertEquals(threadCount, received.get());
+        threads.forEach(t -> assertFalse(t.isAlive()));
+    }
+
+    public void testConsecutiveWritesAtLeastBufferIntervalAway() throws InterruptedException {
+        AtomicInteger received = new AtomicInteger(0);
+        AtomicInteger notified = new AtomicInteger(0);
+        long bufferIntervalMs = randomLongBetween(150, 250);
+        List<Long> writeInvocationTimes = new LinkedList<>();
+
+        AsyncIOProcessor<Object> processor = new BufferedAsyncIOProcessor<>(
+            logger,
+            scaledRandomIntBetween(1, 2024),
+            threadContext,
+            threadpool,
+            () -> TimeValue.timeValueMillis(bufferIntervalMs)
+        ) {
+            @Override
+            protected void write(List<Tuple<Object, Consumer<Exception>>> candidates) throws IOException {
+                received.addAndGet(candidates.size());
+                writeInvocationTimes.add(System.nanoTime());
+            }
+
+            @Override
+            protected String getBufferProcessThreadPoolName() {
+                return ThreadPool.Names.TRANSLOG_SYNC;
+            }
+        };
+
+        int runCount = randomIntBetween(3, 10);
+        CountDownLatch processed = new CountDownLatch(runCount);
+        IntStream.range(0, runCount).forEach(i -> {
+            processor.put(new Object(), (e) -> {
+                notified.incrementAndGet();
+                processed.countDown();
+            });
+        });
+        assertTrue(processed.await(bufferIntervalMs * (runCount + 1), TimeUnit.MILLISECONDS));
+        assertEquals(runCount, notified.get());
+        assertEquals(runCount, received.get());
+        for (int i = 1; i < writeInvocationTimes.size(); i++) {
+            // Resolution of System.nanoTime() is only as good as System.currentTimeMillis() and many operating systems
+            // measure time in units of tens of milliseconds as per Java documentation
+            // https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/System.html#currentTimeMillis()
+            // Keeping a buffer of 20 ms as we are getting time twice with each having resolution of +- 10ms.
+            assertTrue(writeInvocationTimes.get(i) >= writeInvocationTimes.get(i - 1) + (bufferIntervalMs - 20) * 1_000_000);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/ListenableFutureTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/ListenableFutureTests.java
index 32807cf3b88c8..5b7da3b0f95e7 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/ListenableFutureTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/ListenableFutureTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.common.util.concurrent;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/OpenSearchExecutorsTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/OpenSearchExecutorsTests.java
index 61f489f32adfd..2063cd26a9e8e 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/OpenSearchExecutorsTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/OpenSearchExecutorsTests.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matcher;
 
diff --git a/server/src/test/java/org/opensearch/common/util/concurrent/ThreadContextTests.java b/server/src/test/java/org/opensearch/common/util/concurrent/ThreadContextTests.java
index 9c70accaca3e4..a0531c76bf897 100644
--- a/server/src/test/java/org/opensearch/common/util/concurrent/ThreadContextTests.java
+++ b/server/src/test/java/org/opensearch/common/util/concurrent/ThreadContextTests.java
@@ -44,6 +44,7 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
+import static org.opensearch.tasks.TaskResourceTrackingService.TASK_ID;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
 import static org.hamcrest.Matchers.hasSize;
@@ -70,6 +71,35 @@ public void testStashContext() {
         assertEquals("1", threadContext.getHeader("default"));
     }
 
+    public void testStashContextWithPersistentHeaders() {
+        Settings build = Settings.builder().put("request.headers.default", "1").build();
+        ThreadContext threadContext = new ThreadContext(build);
+        threadContext.putHeader("foo", "bar");
+        threadContext.putTransient("ctx.foo", 1);
+        threadContext.putPersistent("persistent_foo", "baz");
+        threadContext.putPersistent("ctx.persistent_foo", 10);
+        assertEquals("bar", threadContext.getHeader("foo"));
+        assertEquals(Integer.valueOf(1), threadContext.getTransient("ctx.foo"));
+        assertEquals("1", threadContext.getHeader("default"));
+        try (ThreadContext.StoredContext ctx = threadContext.stashContext()) {
+            assertNull(threadContext.getHeader("foo"));
+            assertNull(threadContext.getTransient("ctx.foo"));
+            assertEquals("1", threadContext.getHeader("default"));
+
+            assertEquals("baz", threadContext.getPersistent("persistent_foo"));
+            assertEquals(Integer.valueOf(10), threadContext.getPersistent("ctx.persistent_foo"));
+            assertNull(threadContext.getPersistent("default"));
+        }
+
+        assertEquals("bar", threadContext.getHeader("foo"));
+        assertEquals(Integer.valueOf(1), threadContext.getTransient("ctx.foo"));
+        assertEquals("1", threadContext.getHeader("default"));
+
+        assertEquals("baz", threadContext.getPersistent("persistent_foo"));
+        assertEquals(Integer.valueOf(10), threadContext.getPersistent("ctx.persistent_foo"));
+        assertNull(threadContext.getPersistent("default"));
+    }
+
     public void testNewContextWithClearedTransients() {
         ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
         threadContext.putTransient("foo", "bar");
@@ -154,6 +184,15 @@ public void testNewContextWithClearedTransients() {
         assertEquals(1, threadContext.getResponseHeaders().get("baz").size());
     }
 
+    public void testStashContextWithPreservedTransients() {
+        ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
+        threadContext.putTransient("foo", "bar");
+        threadContext.putTransient(TASK_ID, 1);
+        threadContext.stashContext();
+        assertNull(threadContext.getTransient("foo"));
+        assertEquals(1, (int) threadContext.getTransient(TASK_ID));
+    }
+
     public void testStashWithOrigin() {
         final String origin = randomAlphaOfLengthBetween(4, 16);
         final ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
diff --git a/server/src/test/java/org/opensearch/common/xcontent/BaseXContentTestCase.java b/server/src/test/java/org/opensearch/common/xcontent/BaseXContentTestCase.java
index f8b0ec2346abb..779825e20b3f6 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/BaseXContentTestCase.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/BaseXContentTestCase.java
@@ -39,25 +39,36 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Constants;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.io.PathUtils;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.test.OpenSearchTestCase;
-import org.hamcrest.Matcher;
-import org.hamcrest.Matchers;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
 import org.joda.time.Instant;
 import org.joda.time.ReadableInstant;
 import org.joda.time.format.DateTimeFormatter;
 import org.joda.time.format.ISODateTimeFormat;
+import org.hamcrest.Matcher;
+import org.hamcrest.Matchers;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -116,11 +127,11 @@ public void testContentType() throws IOException {
     public void testStartEndObject() throws IOException {
         expectUnclosedException(() -> BytesReference.bytes(builder().startObject()));
         expectUnclosedException(() -> builder().startObject().close());
-        expectUnclosedException(() -> Strings.toString(builder().startObject()));
+        expectUnclosedException(() -> builder().startObject().toString());
 
         expectObjectException(() -> BytesReference.bytes(builder().endObject()));
         expectObjectException(() -> builder().endObject().close());
-        expectObjectException(() -> Strings.toString(builder().endObject()));
+        expectObjectException(() -> builder().endObject().toString());
 
         expectValueException(() -> builder().startObject("foo").endObject());
         expectNonNullFieldException(() -> builder().startObject().startObject(null));
@@ -137,11 +148,11 @@ public void testStartEndObject() throws IOException {
     public void testStartEndArray() throws IOException {
         expectUnclosedException(() -> BytesReference.bytes(builder().startArray()));
         expectUnclosedException(() -> builder().startArray().close());
-        expectUnclosedException(() -> Strings.toString(builder().startArray()));
+        expectUnclosedException(() -> builder().startArray().toString());
 
         expectArrayException(() -> BytesReference.bytes(builder().endArray()));
         expectArrayException(() -> builder().endArray().close());
-        expectArrayException(() -> Strings.toString(builder().endArray()));
+        expectArrayException(() -> builder().endArray().toString());
 
         expectValueException(() -> builder().startArray("foo").endObject());
         expectFieldException(() -> builder().startObject().startArray().endArray().endObject());
@@ -245,6 +256,10 @@ public void testLongs() throws IOException {
         assertResult("{'long':null}", () -> builder().startObject().field("long", (Long) null).endObject());
         assertResult("{'long':42}", () -> builder().startObject().field("long", Long.valueOf(42L)).endObject());
         assertResult("{'long':9223372036854775807}", () -> builder().startObject().field("long", 9_223_372_036_854_775_807L).endObject());
+        assertResult(
+            "{'unsigned_long':18446744073709551615}",
+            () -> builder().startObject().field("unsigned_long", new BigDecimal("18446744073709551615")).endObject()
+        );
         assertResult("{'long':[1,3,5,7,11]}", () -> builder().startObject().array("long", 1L, 3L, 5L, 7L, 11L).endObject());
         assertResult("{'long':null}", () -> builder().startObject().array("long", (long[]) null).endObject());
         assertResult("{'long':[]}", () -> builder().startObject().array("long", new long[] {}).endObject());
@@ -851,7 +866,7 @@ public void testBasics() throws IOException {
             generator.writeEndObject();
         }
         byte[] data = os.toByteArray();
-        assertEquals(xcontentType(), XContentFactory.xContentType(data));
+        assertEquals(xcontentType(), MediaTypeRegistry.xContent(data));
     }
 
     public void testMissingEndObject() throws IOException {
@@ -941,7 +956,7 @@ void doTestRawValue(XContent source) throws Exception {
 
         os = new ByteArrayOutputStream();
         try (XContentGenerator generator = xcontentType().xContent().createGenerator(os)) {
-            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.type());
+            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.mediaType());
         }
 
         try (
@@ -966,7 +981,7 @@ public void close() {
         try (XContentGenerator generator = xcontentType().xContent().createGenerator(os)) {
             generator.writeStartObject();
             generator.writeFieldName("test");
-            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.type());
+            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.mediaType());
             assertFalse("Generator should not have closed the output stream", closed.get());
             generator.writeEndObject();
         }
diff --git a/server/src/test/java/org/opensearch/common/xcontent/XContentFactoryTests.java b/server/src/test/java/org/opensearch/common/xcontent/XContentFactoryTests.java
index cddf02781b600..fdc115281e7aa 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/XContentFactoryTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/XContentFactoryTests.java
@@ -34,9 +34,12 @@
 
 import com.fasterxml.jackson.dataformat.cbor.CBORConstants;
 import com.fasterxml.jackson.dataformat.smile.SmileConstants;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
@@ -47,7 +50,7 @@
 
 public class XContentFactoryTests extends OpenSearchTestCase {
     public void testGuessJson() throws IOException {
-        testGuessType(XContentType.JSON);
+        testGuessType(MediaTypeRegistry.JSON);
     }
 
     public void testGuessSmile() throws IOException {
@@ -62,16 +65,16 @@ public void testGuessCbor() throws IOException {
         testGuessType(XContentType.CBOR);
     }
 
-    private void testGuessType(XContentType type) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(type);
+    private void testGuessType(MediaType type) throws IOException {
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(type);
         builder.startObject();
         builder.field("field1", "value1");
         builder.endObject();
 
         final BytesReference bytes;
-        if (type == XContentType.JSON && randomBoolean()) {
-            final int length = randomIntBetween(0, 8 * XContentFactory.GUESS_HEADER_LENGTH);
-            final String content = Strings.toString(builder);
+        if (type == MediaTypeRegistry.JSON && randomBoolean()) {
+            final int length = randomIntBetween(0, 8 * MediaTypeRegistry.GUESS_HEADER_LENGTH);
+            final String content = builder.toString();
             final StringBuilder sb = new StringBuilder(length + content.length());
             final char[] chars = new char[length];
             Arrays.fill(chars, ' ');
@@ -81,24 +84,24 @@ private void testGuessType(XContentType type) throws IOException {
             bytes = BytesReference.bytes(builder);
         }
 
-        assertThat(XContentHelper.xContentType(bytes), equalTo(type));
-        assertThat(XContentFactory.xContentType(bytes.streamInput()), equalTo(type));
+        assertThat(MediaTypeRegistry.xContentType(bytes), equalTo(type));
+        assertThat(MediaTypeRegistry.xContentType(bytes.streamInput()), equalTo(type));
 
         // CBOR is binary, cannot use String
         if (type != XContentType.CBOR && type != XContentType.SMILE) {
-            assertThat(XContentFactory.xContentType(Strings.toString(builder)), equalTo(type));
+            assertThat(MediaTypeRegistry.xContentType(builder.toString()), equalTo(type));
         }
     }
 
     public void testCBORBasedOnMajorObjectDetection() {
         // for this {"f "=> 5} perl encoder for example generates:
         byte[] bytes = new byte[] { (byte) 0xA1, (byte) 0x43, (byte) 0x66, (byte) 6f, (byte) 6f, (byte) 0x5 };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.CBOR));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(XContentType.CBOR));
         // assertThat(((Number) XContentHelper.convertToMap(bytes, true).v2().get("foo")).intValue(), equalTo(5));
 
         // this if for {"foo" : 5} in python CBOR
         bytes = new byte[] { (byte) 0xA1, (byte) 0x63, (byte) 0x66, (byte) 0x6f, (byte) 0x6f, (byte) 0x5 };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.CBOR));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(XContentType.CBOR));
         assertThat(((Number) XContentHelper.convertToMap(new BytesArray(bytes), true).v2().get("foo")).intValue(), equalTo(5));
 
         // also make sure major type check doesn't collide with SMILE and JSON, just in case
@@ -110,36 +113,36 @@ public void testCBORBasedOnMajorObjectDetection() {
 
     public void testCBORBasedOnMagicHeaderDetection() {
         byte[] bytes = new byte[] { (byte) 0xd9, (byte) 0xd9, (byte) 0xf7 };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.CBOR));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(XContentType.CBOR));
     }
 
     public void testEmptyStream() throws Exception {
         ByteArrayInputStream is = new ByteArrayInputStream(new byte[0]);
-        assertNull(XContentFactory.xContentType(is));
+        assertNull(MediaTypeRegistry.xContentType(is));
 
         is = new ByteArrayInputStream(new byte[] { (byte) 1 });
-        assertNull(XContentFactory.xContentType(is));
+        assertNull(MediaTypeRegistry.xContentType(is));
     }
 
     public void testInvalidStream() throws Exception {
         byte[] bytes = new byte[] { (byte) '"' };
-        assertNull(XContentFactory.xContentType(bytes));
+        assertNull(MediaTypeRegistry.mediaTypeFromBytes(bytes, 0, bytes.length));
 
         bytes = new byte[] { (byte) 'x' };
-        assertNull(XContentFactory.xContentType(bytes));
+        assertNull(MediaTypeRegistry.mediaTypeFromBytes(bytes, 0, bytes.length));
     }
 
     public void testJsonFromBytesOptionallyPrecededByUtf8Bom() throws Exception {
         byte[] bytes = new byte[] { (byte) '{', (byte) '}' };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.JSON));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(MediaTypeRegistry.JSON));
 
         bytes = new byte[] { (byte) 0x20, (byte) '{', (byte) '}' };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.JSON));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(MediaTypeRegistry.JSON));
 
         bytes = new byte[] { (byte) 0xef, (byte) 0xbb, (byte) 0xbf, (byte) '{', (byte) '}' };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.JSON));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(MediaTypeRegistry.JSON));
 
         bytes = new byte[] { (byte) 0xef, (byte) 0xbb, (byte) 0xbf, (byte) 0x20, (byte) '{', (byte) '}' };
-        assertThat(XContentFactory.xContentType(bytes), equalTo(XContentType.JSON));
+        assertThat(MediaTypeRegistry.xContent(bytes), equalTo(MediaTypeRegistry.JSON));
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java b/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
index aafe77a895dbc..60b078be9d639 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
@@ -32,14 +32,22 @@
 
 package org.opensearch.common.xcontent;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -48,10 +56,10 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
-import static org.opensearch.common.xcontent.XContentParserUtils.parseTypedKeysObject;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureFieldName;
+import static org.opensearch.core.xcontent.XContentParserUtils.parseTypedKeysObject;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.endsWith;
 import static org.hamcrest.Matchers.instanceOf;
@@ -106,7 +114,7 @@ public void testStoredFieldsValueBoolean() throws IOException {
     public void testStoredFieldsValueBinary() throws IOException {
         final byte[] value = randomUnicodeOfLength(scaledRandomIntBetween(10, 1000)).getBytes("UTF-8");
         assertParseFieldsSimpleValue(value, (xcontentType, result) -> {
-            if (xcontentType == XContentType.JSON) {
+            if (xcontentType == MediaTypeRegistry.JSON) {
                 // binary values will be parsed back and returned as base64 strings when reading from json
                 assertArrayEquals(value, Base64.getDecoder().decode((String) result));
             } else {
diff --git a/server/src/test/java/org/opensearch/common/xcontent/XContentTypeTests.java b/server/src/test/java/org/opensearch/common/xcontent/XContentTypeTests.java
index 4d4fea5a41b82..53fbcb4659f72 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/XContentTypeTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/XContentTypeTests.java
@@ -31,6 +31,8 @@
 
 package org.opensearch.common.xcontent;
 
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Locale;
@@ -42,73 +44,81 @@ public class XContentTypeTests extends OpenSearchTestCase {
 
     public void testFromJson() throws Exception {
         String mediaType = "application/json";
-        XContentType expectedXContentType = XContentType.JSON;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
+        MediaType expectedXContentType = MediaTypeRegistry.JSON;
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
+    }
+
+    public void testFromNdJson() throws Exception {
+        String mediaType = "application/x-ndjson";
+        MediaType expectedXContentType = MediaTypeRegistry.JSON;
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
     }
 
     public void testFromJsonUppercase() throws Exception {
         String mediaType = "application/json".toUpperCase(Locale.ROOT);
-        XContentType expectedXContentType = XContentType.JSON;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
+        MediaType expectedXContentType = MediaTypeRegistry.JSON;
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
     }
 
     public void testFromYaml() throws Exception {
         String mediaType = "application/yaml";
         XContentType expectedXContentType = XContentType.YAML;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + "; charset=UTF-8"), equalTo(expectedXContentType));
     }
 
     public void testFromSmile() throws Exception {
         String mediaType = "application/smile";
         XContentType expectedXContentType = XContentType.SMILE;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
     }
 
     public void testFromCbor() throws Exception {
         String mediaType = "application/cbor";
         XContentType expectedXContentType = XContentType.CBOR;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
     }
 
     public void testFromWildcard() throws Exception {
         String mediaType = "application/*";
-        XContentType expectedXContentType = XContentType.JSON;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
+        MediaType expectedXContentType = MediaTypeRegistry.JSON;
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
     }
 
     public void testFromWildcardUppercase() throws Exception {
         String mediaType = "APPLICATION/*";
-        XContentType expectedXContentType = XContentType.JSON;
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType), equalTo(expectedXContentType));
-        assertThat(XContentType.fromMediaTypeOrFormat(mediaType + ";"), equalTo(expectedXContentType));
+        MediaType expectedXContentType = MediaTypeRegistry.JSON;
+        assertThat(MediaType.fromMediaType(mediaType), equalTo(expectedXContentType));
+        assertThat(MediaType.fromMediaType(mediaType + ";"), equalTo(expectedXContentType));
     }
 
     public void testFromRubbish() throws Exception {
-        assertThat(XContentType.fromMediaTypeOrFormat(null), nullValue());
-        assertThat(XContentType.fromMediaTypeOrFormat(""), nullValue());
-        assertThat(XContentType.fromMediaTypeOrFormat("text/plain"), nullValue());
-        assertThat(XContentType.fromMediaTypeOrFormat("gobbly;goop"), nullValue());
+        assertThat(MediaType.fromMediaType(null), nullValue());
+        assertThat(MediaType.fromMediaType(""), nullValue());
+        assertThat(MediaType.fromMediaType("text/plain"), nullValue());
+        assertThat(MediaType.fromMediaType("gobbly;goop"), nullValue());
     }
 
     public void testVersionedMediaType() throws Exception {
-        assertThat(XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+json;compatible-with=7"), equalTo(XContentType.JSON));
-        assertThat(XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+yaml;compatible-with=7"), equalTo(XContentType.YAML));
-        assertThat(XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+cbor;compatible-with=7"), equalTo(XContentType.CBOR));
-        assertThat(XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+smile;compatible-with=7"), equalTo(XContentType.SMILE));
-
-        assertThat(XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+json ;compatible-with=7"), equalTo(XContentType.JSON));
-        assertThat(
-            XContentType.fromMediaTypeOrFormat("application/vnd.opensearch+json ;compatible-with=7;charset=utf-8"),
-            equalTo(XContentType.JSON)
-        );
+        assertThat(MediaType.fromMediaType("application/vnd.opensearch+json;compatible-with=7"), equalTo(MediaTypeRegistry.JSON));
+        assertThat(MediaType.fromMediaType("application/vnd.opensearch+yaml;compatible-with=7"), equalTo(XContentType.YAML));
+        assertThat(MediaType.fromMediaType("application/vnd.opensearch+cbor;compatible-with=7"), equalTo(XContentType.CBOR));
+        assertThat(MediaType.fromMediaType("application/vnd.opensearch+smile;compatible-with=7"), equalTo(XContentType.SMILE));
+
+        assertThat(MediaType.fromMediaType("application/vnd.opensearch+json ;compatible-with=7"), equalTo(MediaTypeRegistry.JSON));
+
+        String mthv = "application/vnd.opensearch+json ;compatible-with=7;charset=utf-8";
+        assertThat(MediaType.fromMediaType(mthv), equalTo(MediaTypeRegistry.JSON));
+        assertThat(MediaType.fromMediaType(mthv.toUpperCase(Locale.ROOT)), equalTo(MediaTypeRegistry.JSON));
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/xcontent/builder/XContentBuilderTests.java b/server/src/test/java/org/opensearch/common/xcontent/builder/XContentBuilderTests.java
index ad695c2a20e27..184f90df785c7 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/builder/XContentBuilderTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/builder/XContentBuilderTests.java
@@ -33,19 +33,18 @@
 package org.opensearch.common.xcontent.builder;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentOpenSearchExtension;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayOutputStream;
@@ -68,7 +67,7 @@
 public class XContentBuilderTests extends OpenSearchTestCase {
     public void testPrettyWithLfAtEnd() throws Exception {
         ByteArrayOutputStream os = new ByteArrayOutputStream();
-        XContentGenerator generator = XContentFactory.xContent(XContentType.JSON).createGenerator(os);
+        XContentGenerator generator = MediaTypeRegistry.JSON.xContent().createGenerator(os);
         generator.usePrettyPrint();
         generator.usePrintLineFeedAtEnd();
 
@@ -87,7 +86,7 @@ public void testPrettyWithLfAtEnd() throws Exception {
 
     public void testReuseJsonGenerator() throws Exception {
         ByteArrayOutputStream os = new ByteArrayOutputStream();
-        XContentGenerator generator = XContentFactory.xContent(XContentType.JSON).createGenerator(os);
+        XContentGenerator generator = MediaTypeRegistry.JSON.xContent().createGenerator(os);
         generator.writeStartObject();
         generator.writeStringField("test", "value");
         generator.writeEndObject();
@@ -107,42 +106,39 @@ public void testReuseJsonGenerator() throws Exception {
 
     public void testRaw() throws IOException {
         {
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             xContentBuilder.startObject();
             xContentBuilder.rawField("foo", new BytesArray("{\"test\":\"value\"}").streamInput());
             xContentBuilder.endObject();
-            assertThat(Strings.toString(xContentBuilder), equalTo("{\"foo\":{\"test\":\"value\"}}"));
+            assertThat(xContentBuilder.toString(), equalTo("{\"foo\":{\"test\":\"value\"}}"));
         }
         {
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             xContentBuilder.startObject();
             xContentBuilder.rawField("foo", new BytesArray("{\"test\":\"value\"}").streamInput());
             xContentBuilder.rawField("foo1", new BytesArray("{\"test\":\"value\"}").streamInput());
             xContentBuilder.endObject();
-            assertThat(Strings.toString(xContentBuilder), equalTo("{\"foo\":{\"test\":\"value\"},\"foo1\":{\"test\":\"value\"}}"));
+            assertThat(xContentBuilder.toString(), equalTo("{\"foo\":{\"test\":\"value\"},\"foo1\":{\"test\":\"value\"}}"));
         }
         {
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             xContentBuilder.startObject();
             xContentBuilder.field("test", "value");
             xContentBuilder.rawField("foo", new BytesArray("{\"test\":\"value\"}").streamInput());
             xContentBuilder.endObject();
-            assertThat(Strings.toString(xContentBuilder), equalTo("{\"test\":\"value\",\"foo\":{\"test\":\"value\"}}"));
+            assertThat(xContentBuilder.toString(), equalTo("{\"test\":\"value\",\"foo\":{\"test\":\"value\"}}"));
         }
         {
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             xContentBuilder.startObject();
             xContentBuilder.field("test", "value");
             xContentBuilder.rawField("foo", new BytesArray("{\"test\":\"value\"}").streamInput());
             xContentBuilder.field("test1", "value1");
             xContentBuilder.endObject();
-            assertThat(
-                Strings.toString(xContentBuilder),
-                equalTo("{\"test\":\"value\",\"foo\":{\"test\":\"value\"},\"test1\":\"value1\"}")
-            );
+            assertThat(xContentBuilder.toString(), equalTo("{\"test\":\"value\",\"foo\":{\"test\":\"value\"},\"test1\":\"value1\"}"));
         }
         {
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             xContentBuilder.startObject();
             xContentBuilder.field("test", "value");
             xContentBuilder.rawField("foo", new BytesArray("{\"test\":\"value\"}").streamInput());
@@ -150,32 +146,32 @@ public void testRaw() throws IOException {
             xContentBuilder.field("test1", "value1");
             xContentBuilder.endObject();
             assertThat(
-                Strings.toString(xContentBuilder),
+                xContentBuilder.toString(),
                 equalTo("{\"test\":\"value\",\"foo\":{\"test\":\"value\"},\"foo1\":{\"test\":\"value\"},\"test1\":\"value1\"}")
             );
         }
     }
 
     public void testSimpleGenerator() throws Exception {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("test", "value").endObject();
-        assertThat(Strings.toString(builder), equalTo("{\"test\":\"value\"}"));
+        assertThat(builder.toString(), equalTo("{\"test\":\"value\"}"));
 
-        builder = XContentFactory.contentBuilder(XContentType.JSON);
+        builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("test", "value").endObject();
-        assertThat(Strings.toString(builder), equalTo("{\"test\":\"value\"}"));
+        assertThat(builder.toString(), equalTo("{\"test\":\"value\"}"));
     }
 
     public void testOverloadedList() throws Exception {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("test", Arrays.asList("1", "2")).endObject();
-        assertThat(Strings.toString(builder), equalTo("{\"test\":[\"1\",\"2\"]}"));
+        assertThat(builder.toString(), equalTo("{\"test\":[\"1\",\"2\"]}"));
     }
 
     public void testWritingBinaryToStream() throws Exception {
         BytesStreamOutput bos = new BytesStreamOutput();
 
-        XContentGenerator gen = XContentFactory.xContent(XContentType.JSON).createGenerator(bos);
+        XContentGenerator gen = MediaTypeRegistry.JSON.xContent().createGenerator(bos);
         gen.writeStartObject();
         gen.writeStringField("name", "something");
         gen.flush();
@@ -189,7 +185,7 @@ public void testWritingBinaryToStream() throws Exception {
     }
 
     public void testByteConversion() throws Exception {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("test_name", (Byte) (byte) 120).endObject();
         assertThat(BytesReference.bytes(builder).utf8ToString(), equalTo("{\"test_name\":120}"));
     }
@@ -199,29 +195,29 @@ public void testDateTypesConversion() throws Exception {
         String expectedDate = XContentOpenSearchExtension.DEFAULT_DATE_PRINTER.print(date.getTime());
         Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"), Locale.ROOT);
         String expectedCalendar = XContentOpenSearchExtension.DEFAULT_DATE_PRINTER.print(calendar.getTimeInMillis());
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().timeField("date", date).endObject();
-        assertThat(Strings.toString(builder), equalTo("{\"date\":\"" + expectedDate + "\"}"));
+        assertThat(builder.toString(), equalTo("{\"date\":\"" + expectedDate + "\"}"));
 
-        builder = XContentFactory.contentBuilder(XContentType.JSON);
+        builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("calendar", calendar).endObject();
-        assertThat(Strings.toString(builder), equalTo("{\"calendar\":\"" + expectedCalendar + "\"}"));
+        assertThat(builder.toString(), equalTo("{\"calendar\":\"" + expectedCalendar + "\"}"));
 
-        builder = XContentFactory.contentBuilder(XContentType.JSON);
+        builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         Map<String, Object> map = new HashMap<>();
         map.put("date", date);
         builder.map(map);
-        assertThat(Strings.toString(builder), equalTo("{\"date\":\"" + expectedDate + "\"}"));
+        assertThat(builder.toString(), equalTo("{\"date\":\"" + expectedDate + "\"}"));
 
-        builder = XContentFactory.contentBuilder(XContentType.JSON);
+        builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         map = new HashMap<>();
         map.put("calendar", calendar);
         builder.map(map);
-        assertThat(Strings.toString(builder), equalTo("{\"calendar\":\"" + expectedCalendar + "\"}"));
+        assertThat(builder.toString(), equalTo("{\"calendar\":\"" + expectedCalendar + "\"}"));
     }
 
     public void testCopyCurrentStructure() throws Exception {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         builder.startObject().field("test", "test field").startObject("filter").startObject("terms");
 
         // up to 20k random terms
@@ -248,7 +244,7 @@ public void testCopyCurrentStructure() throws Exception {
                     }
                 } else if (token == XContentParser.Token.START_OBJECT) {
                     if ("filter".equals(currentFieldName)) {
-                        filterBuilder = XContentFactory.contentBuilder(parser.contentType());
+                        filterBuilder = MediaTypeRegistry.contentBuilder(parser.contentType());
                         filterBuilder.copyCurrentStructure(parser);
                     }
                 }
@@ -288,61 +284,61 @@ public void testHandlingOfPath_absolute() throws IOException {
     }
 
     private void checkPathSerialization(Path path) throws IOException {
-        XContentBuilder pathBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder pathBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         pathBuilder.startObject().field("file", path).endObject();
 
-        XContentBuilder stringBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder stringBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         stringBuilder.startObject().field("file", path.toString()).endObject();
 
-        assertThat(Strings.toString(pathBuilder), equalTo(Strings.toString(stringBuilder)));
+        assertThat(pathBuilder.toString(), equalTo(stringBuilder.toString()));
     }
 
     public void testHandlingOfPath_StringName() throws IOException {
         Path path = PathUtils.get("path");
         String name = new String("file");
 
-        XContentBuilder pathBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder pathBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         pathBuilder.startObject().field(name, path).endObject();
 
-        XContentBuilder stringBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder stringBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         stringBuilder.startObject().field(name, path.toString()).endObject();
 
-        assertThat(Strings.toString(pathBuilder), equalTo(Strings.toString(stringBuilder)));
+        assertThat(pathBuilder.toString(), equalTo(stringBuilder.toString()));
     }
 
     public void testHandlingOfCollectionOfPaths() throws IOException {
         Path path = PathUtils.get("path");
 
-        XContentBuilder pathBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder pathBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         pathBuilder.startObject().field("file", Arrays.asList(path)).endObject();
 
-        XContentBuilder stringBuilder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder stringBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
         stringBuilder.startObject().field("file", Arrays.asList(path.toString())).endObject();
 
-        assertThat(Strings.toString(pathBuilder), equalTo(Strings.toString(stringBuilder)));
+        assertThat(pathBuilder.toString(), equalTo(stringBuilder.toString()));
     }
 
     public void testIndentIsPlatformIndependent() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON).prettyPrint();
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON).prettyPrint();
         builder.startObject().field("test", "foo").startObject("foo").field("foobar", "boom").endObject().endObject();
-        String string = Strings.toString(builder);
+        String string = builder.toString();
         assertEquals("{\n" + "  \"test\" : \"foo\",\n" + "  \"foo\" : {\n" + "    \"foobar\" : \"boom\"\n" + "  }\n" + "}", string);
 
-        builder = XContentFactory.contentBuilder(XContentType.YAML).prettyPrint();
+        builder = MediaTypeRegistry.contentBuilder(XContentType.YAML).prettyPrint();
         builder.startObject().field("test", "foo").startObject("foo").field("foobar", "boom").endObject().endObject();
-        string = Strings.toString(builder);
+        string = builder.toString();
         assertEquals("---\n" + "test: \"foo\"\n" + "foo:\n" + "  foobar: \"boom\"\n", string);
     }
 
     public void testRenderGeoPoint() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON).prettyPrint();
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON).prettyPrint();
         builder.startObject().field("foo").value(new GeoPoint(1, 2)).endObject();
-        String string = Strings.toString(builder);
+        String string = builder.toString();
         assertEquals("{\n" + "  \"foo\" : {\n" + "    \"lat\" : 1.0,\n" + "    \"lon\" : 2.0\n" + "  }\n" + "}", string.trim());
     }
 
     public void testWriteMapWithNullKeys() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         try {
             builder.map(Collections.singletonMap(null, "test"));
             fail("write map should have failed");
@@ -352,7 +348,7 @@ public void testWriteMapWithNullKeys() throws IOException {
     }
 
     public void testWriteMapValueWithNullKeys() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         try {
             builder.map(Collections.singletonMap(null, "test"));
             fail("write map should have failed");
@@ -362,7 +358,7 @@ public void testWriteMapValueWithNullKeys() throws IOException {
     }
 
     public void testWriteFieldMapWithNullKeys() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         try {
             builder.startObject();
             builder.field("map", Collections.singletonMap(null, "test"));
@@ -374,7 +370,7 @@ public void testWriteFieldMapWithNullKeys() throws IOException {
 
     public void testMissingEndObject() throws IOException {
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
-            try (XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()))) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()))) {
                 builder.startObject();
                 builder.field("foo", true);
             }
@@ -385,7 +381,7 @@ public void testMissingEndObject() throws IOException {
 
     public void testMissingEndArray() throws IOException {
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
-            try (XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()))) {
+            try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()))) {
                 builder.startObject();
                 builder.startArray("foo");
                 builder.value(0);
diff --git a/server/src/test/java/org/opensearch/common/xcontent/cbor/CborXContentParserTests.java b/server/src/test/java/org/opensearch/common/xcontent/cbor/CborXContentParserTests.java
index b425328ee5001..d471b8674be24 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/cbor/CborXContentParserTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/cbor/CborXContentParserTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.common.xcontent.cbor;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/xcontent/cbor/JsonVsCborTests.java b/server/src/test/java/org/opensearch/common/xcontent/cbor/JsonVsCborTests.java
index f0ae7e0ce4234..f4ca3c5117196 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/cbor/JsonVsCborTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/cbor/JsonVsCborTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.common.xcontent.cbor;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -48,10 +48,10 @@
 public class JsonVsCborTests extends OpenSearchTestCase {
     public void testCompareParsingTokens() throws IOException {
         BytesStreamOutput xsonOs = new BytesStreamOutput();
-        XContentGenerator xsonGen = XContentFactory.xContent(XContentType.CBOR).createGenerator(xsonOs);
+        XContentGenerator xsonGen = XContentType.CBOR.xContent().createGenerator(xsonOs);
 
         BytesStreamOutput jsonOs = new BytesStreamOutput();
-        XContentGenerator jsonGen = XContentFactory.xContent(XContentType.JSON).createGenerator(jsonOs);
+        XContentGenerator jsonGen = MediaTypeRegistry.JSON.xContent().createGenerator(jsonOs);
 
         xsonGen.writeStartObject();
         jsonGen.writeStartObject();
diff --git a/server/src/test/java/org/opensearch/common/xcontent/smile/JsonVsSmileTests.java b/server/src/test/java/org/opensearch/common/xcontent/smile/JsonVsSmileTests.java
index 376d65a3f5fda..5b5871e9b5084 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/smile/JsonVsSmileTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/smile/JsonVsSmileTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.common.xcontent.smile;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -48,10 +48,10 @@
 public class JsonVsSmileTests extends OpenSearchTestCase {
     public void testCompareParsingTokens() throws IOException {
         BytesStreamOutput xsonOs = new BytesStreamOutput();
-        XContentGenerator xsonGen = XContentFactory.xContent(XContentType.SMILE).createGenerator(xsonOs);
+        XContentGenerator xsonGen = XContentType.SMILE.xContent().createGenerator(xsonOs);
 
         BytesStreamOutput jsonOs = new BytesStreamOutput();
-        XContentGenerator jsonGen = XContentFactory.xContent(XContentType.JSON).createGenerator(jsonOs);
+        XContentGenerator jsonGen = MediaTypeRegistry.JSON.xContent().createGenerator(jsonOs);
 
         xsonGen.writeStartObject();
         jsonGen.writeStartObject();
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/AbstractFilteringTestCase.java b/server/src/test/java/org/opensearch/common/xcontent/support/AbstractFilteringTestCase.java
index 7c61a07525819..e3eeeaaf62f18 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/AbstractFilteringTestCase.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/AbstractFilteringTestCase.java
@@ -33,10 +33,10 @@
 package org.opensearch.common.xcontent.support;
 
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/XContentHelperTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/XContentHelperTests.java
index ecf0d9a601129..297b9f4b39751 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/XContentHelperTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/XContentHelperTests.java
@@ -32,16 +32,17 @@
 
 package org.opensearch.common.xcontent.support;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
@@ -211,7 +212,7 @@ public void testChildBytes() throws IOException {
     }
 
     public void testEmbeddedObject() throws IOException {
-        // Need to test this separately as XContentType.JSON never produces VALUE_EMBEDDED_OBJECT
+        // Need to test this separately as MediaTypeRegistry.JSON never produces VALUE_EMBEDDED_OBJECT
         XContentBuilder builder = XContentBuilder.builder(XContentType.CBOR.xContent());
         builder.startObject().startObject("root");
         CompressedXContent embedded = new CompressedXContent("{\"field\":\"value\"}");
@@ -252,7 +253,7 @@ public void testEmptyChildBytes() throws IOException {
 
         String inputJson = "{ \"mappings\" : {} }";
         try (
-            XContentParser parser = XContentType.JSON.xContent()
+            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, inputJson)
         ) {
 
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/XContentMapValuesTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/XContentMapValuesTests.java
index 8d8ba9872ee61..c94d667bfe9f4 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/XContentMapValuesTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/XContentMapValuesTests.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.common.xcontent.support;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContentObject;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -54,7 +55,7 @@
 import static java.util.Collections.emptySet;
 import static java.util.Collections.singleton;
 import static org.opensearch.common.xcontent.XContentHelper.convertToMap;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.hamcrest.Matchers.hasEntry;
 import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.hasSize;
@@ -94,7 +95,7 @@ public void testExtractValue() throws Exception {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().field("test", "value").endObject();
 
         Map<String, Object> map;
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractValue("test", map).toString(), equalTo("value"));
@@ -110,7 +111,7 @@ public void testExtractValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractValue("path1.path2.test", map).toString(), equalTo("value"));
@@ -135,7 +136,7 @@ public void testExtractValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
 
@@ -159,7 +160,7 @@ public void testExtractValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
 
@@ -173,7 +174,7 @@ public void testExtractValue() throws Exception {
 
         // fields with . in them
         builder = XContentFactory.jsonBuilder().startObject().field("xxx.yyy", "value").endObject();
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractValue("xxx.yyy", map).toString(), equalTo("value"));
@@ -187,7 +188,7 @@ public void testExtractValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractValue("path1.xxx.path2.yyy.test", map).toString(), equalTo("value"));
@@ -215,7 +216,7 @@ public void testExtractValueWithNullValue() throws Exception {
             .endObject();
 
         Map<String, Object> map;
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertEquals("value", XContentMapValues.extractValue("field", map, "NULL"));
@@ -224,14 +225,8 @@ public void testExtractValueWithNullValue() throws Exception {
         assertNull(XContentMapValues.extractValue("object1.missing", map, "NULL"));
 
         assertEquals("NULL", XContentMapValues.extractValue("other_field", map, "NULL"));
-        assertEquals(
-            org.opensearch.common.collect.List.of("value1", "NULL", "value2"),
-            XContentMapValues.extractValue("array", map, "NULL")
-        );
-        assertEquals(
-            org.opensearch.common.collect.List.of("NULL", "value"),
-            XContentMapValues.extractValue("object_array.field", map, "NULL")
-        );
+        assertEquals(List.of("value1", "NULL", "value2"), XContentMapValues.extractValue("array", map, "NULL"));
+        assertEquals(List.of("NULL", "value"), XContentMapValues.extractValue("object_array.field", map, "NULL"));
         assertEquals("NULL", XContentMapValues.extractValue("object1.object2.field", map, "NULL"));
     }
 
@@ -239,14 +234,14 @@ public void testExtractRawValue() throws Exception {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().field("test", "value").endObject();
 
         Map<String, Object> map;
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractRawValues("test", map).get(0).toString(), equalTo("value"));
 
         builder = XContentFactory.jsonBuilder().startObject().field("test.me", "value").endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractRawValues("test.me", map).get(0).toString(), equalTo("value"));
@@ -260,7 +255,7 @@ public void testExtractRawValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractRawValues("path1.path2.test", map).get(0).toString(), equalTo("value"));
@@ -274,7 +269,7 @@ public void testExtractRawValue() throws Exception {
             .endObject()
             .endObject();
 
-        try (XContentParser parser = createParser(JsonXContent.jsonXContent, Strings.toString(builder))) {
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, builder.toString())) {
             map = parser.map();
         }
         assertThat(XContentMapValues.extractRawValues("path1.xxx.path2.yyy.test", map).get(0).toString(), equalTo("value"));
@@ -428,7 +423,7 @@ public void testFilterWithEmptyIncludesExcludes() {
     public void testThatFilterIncludesEmptyObjectWhenUsingIncludes() throws Exception {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().startObject("obj").endObject().endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
+        Tuple<? extends MediaType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), new String[] { "obj" }, Strings.EMPTY_ARRAY);
 
         assertThat(mapTuple.v2(), equalTo(filteredSource));
@@ -437,7 +432,7 @@ public void testThatFilterIncludesEmptyObjectWhenUsingIncludes() throws Exceptio
     public void testThatFilterIncludesEmptyObjectWhenUsingExcludes() throws Exception {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().startObject("obj").endObject().endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
+        Tuple<? extends MediaType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(
             mapTuple.v2(),
             Strings.EMPTY_ARRAY,
@@ -451,7 +446,7 @@ public void testThatFilterIncludesEmptyObjectWhenUsingExcludes() throws Exceptio
     public void testNotOmittingObjectsWithExcludedProperties() throws Exception {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject().startObject("obj").field("f1", "v1").endObject().endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
+        Tuple<? extends MediaType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), Strings.EMPTY_ARRAY, new String[] { "obj.f1" });
 
         assertThat(filteredSource.size(), equalTo(1));
@@ -472,7 +467,7 @@ public void testNotOmittingObjectWithNestedExcludedObject() throws Exception {
             .endObject();
 
         // implicit include
-        Tuple<XContentType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
+        Tuple<? extends MediaType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), Strings.EMPTY_ARRAY, new String[] { "*.obj2" });
 
         assertThat(filteredSource.size(), equalTo(1));
@@ -503,7 +498,7 @@ public void testIncludingObjectWithNestedIncludedObject() throws Exception {
             .endObject()
             .endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
+        Tuple<? extends MediaType, Map<String, Object>> mapTuple = convertToMap(BytesReference.bytes(builder), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), new String[] { "*.obj2" }, Strings.EMPTY_ARRAY);
 
         assertThat(filteredSource.size(), equalTo(1));
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/AbstractXContentFilteringTestCase.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/AbstractXContentFilteringTestCase.java
index 53a0e26cdd059..4ff1140d5fe4d 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/AbstractXContentFilteringTestCase.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/AbstractXContentFilteringTestCase.java
@@ -32,16 +32,15 @@
 
 package org.opensearch.common.xcontent.support.filtering;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.AbstractFilteringTestCase;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.junit.Assert;
 
 import java.io.IOException;
 import java.util.Set;
@@ -84,11 +83,11 @@ public void testSingleFieldObject() throws IOException {
     }
 
     static void assertXContentBuilderAsString(final XContentBuilder expected, final XContentBuilder actual) {
-        assertThat(Strings.toString(actual), is(Strings.toString(expected)));
+        Assert.assertThat(actual.toString(), is(expected.toString()));
     }
 
     static void assertXContentBuilderAsBytes(final XContentBuilder expected, final XContentBuilder actual) {
-        XContent xContent = XContentFactory.xContent(actual.contentType());
+        XContent xContent = actual.contentType().xContent();
         try (
             XContentParser jsonParser = xContent.createParser(
                 NamedXContentRegistry.EMPTY,
@@ -105,25 +104,25 @@ static void assertXContentBuilderAsBytes(final XContentBuilder expected, final X
                 XContentParser.Token token1 = jsonParser.nextToken();
                 XContentParser.Token token2 = testParser.nextToken();
                 if (token1 == null) {
-                    assertThat(token2, nullValue());
+                    Assert.assertThat(token2, nullValue());
                     return;
                 }
-                assertThat(token1, equalTo(token2));
+                Assert.assertThat(token1, equalTo(token2));
                 switch (token1) {
                     case FIELD_NAME:
-                        assertThat(jsonParser.currentName(), equalTo(testParser.currentName()));
+                        Assert.assertThat(jsonParser.currentName(), equalTo(testParser.currentName()));
                         break;
                     case VALUE_STRING:
-                        assertThat(jsonParser.text(), equalTo(testParser.text()));
+                        Assert.assertThat(jsonParser.text(), equalTo(testParser.text()));
                         break;
                     case VALUE_NUMBER:
-                        assertThat(jsonParser.numberType(), equalTo(testParser.numberType()));
-                        assertThat(jsonParser.numberValue(), equalTo(testParser.numberValue()));
+                        Assert.assertThat(jsonParser.numberType(), equalTo(testParser.numberType()));
+                        Assert.assertThat(jsonParser.numberValue(), equalTo(testParser.numberValue()));
                         break;
                 }
             }
         } catch (Exception e) {
-            fail("Fail to verify the result of the XContentBuilder: " + e.getMessage());
+            Assert.fail("Fail to verify the result of the XContentBuilder: " + e.getMessage());
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/CborXContentFilteringTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/CborXContentFilteringTests.java
index d81bc19f2c4dd..a728f3c1be766 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/CborXContentFilteringTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/CborXContentFilteringTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.common.xcontent.support.filtering;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 public class CborXContentFilteringTests extends AbstractXContentFilteringTestCase {
 
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathGeneratorFilteringTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathGeneratorFilteringTests.java
index e3b5bfb0a4bf6..3dc209877214a 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathGeneratorFilteringTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/FilterPathGeneratorFilteringTests.java
@@ -35,7 +35,9 @@
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.filter.FilteringGeneratorDelegate;
+
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.xcontent.filtering.FilterPathBasedFilter;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/JsonXContentFilteringTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/JsonXContentFilteringTests.java
index 535f854a3b7ae..62adad8e593a9 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/JsonXContentFilteringTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/JsonXContentFilteringTests.java
@@ -32,8 +32,9 @@
 
 package org.opensearch.common.xcontent.support.filtering;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.test.OpenSearchTestCase;
 
 public class JsonXContentFilteringTests extends AbstractXContentFilteringTestCase {
 
@@ -44,10 +45,10 @@ protected XContentType getXContentType() {
 
     @Override
     protected void assertFilterResult(XContentBuilder expected, XContentBuilder actual) {
-        if (randomBoolean()) {
-            assertXContentBuilderAsString(expected, actual);
+        if (OpenSearchTestCase.randomBoolean()) {
+            AbstractXContentFilteringTestCase.assertXContentBuilderAsString(expected, actual);
         } else {
-            assertXContentBuilderAsBytes(expected, actual);
+            AbstractXContentFilteringTestCase.assertXContentBuilderAsBytes(expected, actual);
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/SmileFilteringGeneratorTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/SmileFilteringGeneratorTests.java
index 9155eb2d05ed8..8340fae311464 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/SmileFilteringGeneratorTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/SmileFilteringGeneratorTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.common.xcontent.support.filtering;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 public class SmileFilteringGeneratorTests extends AbstractXContentFilteringTestCase {
 
diff --git a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/YamlFilteringGeneratorTests.java b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/YamlFilteringGeneratorTests.java
index b8ff2227a311f..c33b285067e08 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/support/filtering/YamlFilteringGeneratorTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/support/filtering/YamlFilteringGeneratorTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.common.xcontent.support.filtering;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 public class YamlFilteringGeneratorTests extends AbstractXContentFilteringTestCase {
 
diff --git a/server/src/test/java/org/opensearch/core/RestStatusTests.java b/server/src/test/java/org/opensearch/core/RestStatusTests.java
new file mode 100644
index 0000000000000..f8dba99aa8b60
--- /dev/null
+++ b/server/src/test/java/org/opensearch/core/RestStatusTests.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.PriorityQueue;
+
+public class RestStatusTests extends OpenSearchTestCase {
+
+    public void testStatusReturns200ForNoFailures() {
+        int totalShards = randomIntBetween(1, 100);
+        int successfulShards = randomIntBetween(1, totalShards);
+
+        assertEquals(RestStatus.OK, RestStatus.status(successfulShards, totalShards));
+    }
+
+    public void testStatusReturns503ForUnavailableShards() {
+        int totalShards = randomIntBetween(1, 100);
+        int successfulShards = 0;
+
+        assertEquals(RestStatus.SERVICE_UNAVAILABLE, RestStatus.status(successfulShards, totalShards));
+    }
+
+    public void testStatusReturnsFailureStatusWhenFailuresExist() {
+        int totalShards = randomIntBetween(1, 100);
+        int successfulShards = 0;
+
+        TestException[] failures = new TestException[totalShards];
+        PriorityQueue<TestException> heapOfFailures = new PriorityQueue<>((x, y) -> y.status().compareTo(x.status()));
+
+        for (int i = 0; i < totalShards; ++i) {
+            /*
+             * Status here doesn't need to convey failure and is not as per rest
+             * contract. We're not testing the contract, but if status() returns
+             * the greatest rest code from the failures selection
+             */
+            RestStatus status = randomFrom(RestStatus.values());
+            TestException failure = new TestException(status);
+
+            failures[i] = failure;
+            heapOfFailures.add(failure);
+        }
+
+        assertEquals(heapOfFailures.peek().status(), RestStatus.status(successfulShards, totalShards, failures));
+    }
+
+    public void testSerialization() throws IOException {
+        final RestStatus status = randomFrom(RestStatus.values());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            RestStatus.writeTo(out, status);
+
+            try (StreamInput in = out.bytes().streamInput()) {
+                RestStatus deserializedStatus = RestStatus.readFrom(in);
+
+                assertEquals(status, deserializedStatus);
+            }
+        }
+    }
+
+    private static class TestException extends ShardOperationFailedException {
+        TestException(final RestStatus status) {
+            super("super-idx", randomInt(), "gone-fishing", status, new Throwable("cake"));
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            throw new IOException("not implemented");
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            throw new IOException("not implemented");
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/crypto/CryptoHandlerRegistryTests.java b/server/src/test/java/org/opensearch/crypto/CryptoHandlerRegistryTests.java
new file mode 100644
index 0000000000000..93a7b3d3eb4b9
--- /dev/null
+++ b/server/src/test/java/org/opensearch/crypto/CryptoHandlerRegistryTests.java
@@ -0,0 +1,168 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto;
+
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.MasterKeyProvider;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.plugins.CryptoKeyProviderPlugin;
+import org.opensearch.plugins.CryptoPlugin;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
+import org.mockito.ArgumentMatchers;
+import org.mockito.Mockito;
+
+public class CryptoHandlerRegistryTests extends OpenSearchTestCase {
+
+    private TestCryptoHandlerRegistry cryptoManagerRegistry;
+    private String pluginTypeWithCreationFailure;
+    private CryptoKeyProviderPlugin cryptoPlugin1;
+    private CryptoKeyProviderPlugin cryptoPlugin2;
+
+    @Before
+    public void setup() {
+        List<CryptoKeyProviderPlugin> cryptoKPPlugins = new ArrayList<>();
+        CryptoKeyProviderPlugin cryptoPlugin1 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        String pluginType1 = UUID.randomUUID().toString();
+        Mockito.when(cryptoPlugin1.type()).thenReturn(pluginType1);
+        MasterKeyProvider masterKeyProvider1 = Mockito.mock(MasterKeyProvider.class);
+        Mockito.when(cryptoPlugin1.createKeyProvider(ArgumentMatchers.any())).thenReturn(masterKeyProvider1);
+        this.cryptoPlugin1 = cryptoPlugin1;
+        cryptoKPPlugins.add(cryptoPlugin1);
+
+        CryptoKeyProviderPlugin cryptoPlugin2 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        String pluginType2 = UUID.randomUUID().toString();
+        Mockito.when(cryptoPlugin2.type()).thenReturn(pluginType2);
+        MasterKeyProvider masterKeyProvider2 = Mockito.mock(MasterKeyProvider.class);
+        Mockito.when(cryptoPlugin2.createKeyProvider(ArgumentMatchers.any())).thenReturn(masterKeyProvider2);
+        cryptoKPPlugins.add(cryptoPlugin2);
+        this.cryptoPlugin2 = cryptoPlugin2;
+
+        CryptoKeyProviderPlugin cryptoPluginCreationFailure = Mockito.mock(CryptoKeyProviderPlugin.class);
+        pluginTypeWithCreationFailure = UUID.randomUUID().toString();
+        Mockito.when(cryptoPluginCreationFailure.type()).thenReturn(pluginTypeWithCreationFailure);
+        Mockito.when(cryptoPluginCreationFailure.createKeyProvider(ArgumentMatchers.any()))
+            .thenThrow(new RuntimeException("Injected failure"));
+        cryptoKPPlugins.add(cryptoPluginCreationFailure);
+
+        cryptoManagerRegistry = new TestCryptoHandlerRegistry(new TestCryptoPlugin(), cryptoKPPlugins, Settings.EMPTY);
+    }
+
+    static class TestCryptoPlugin implements CryptoPlugin {
+
+        @Override
+        public CryptoHandler getOrCreateCryptoHandler(
+            MasterKeyProvider keyProvider,
+            String keyProviderName,
+            String keyProviderType,
+            Runnable onClose
+        ) {
+            return Mockito.mock(CryptoHandler.class);
+        }
+    }
+
+    static class TestCryptoHandlerRegistry extends CryptoHandlerRegistry {
+
+        protected TestCryptoHandlerRegistry(CryptoPlugin cryptoPlugin, List<CryptoKeyProviderPlugin> cryptoPlugins, Settings settings) {
+            super(List.of(cryptoPlugin), cryptoPlugins, settings);
+        }
+
+        @Override
+        public Map<String, CryptoKeyProviderPlugin> loadCryptoFactories(List<CryptoKeyProviderPlugin> cryptoKPPlugins) {
+            return super.loadCryptoFactories(cryptoKPPlugins);
+        }
+    }
+
+    public void testInitRegistryWithDuplicateKPType() {
+        List<CryptoKeyProviderPlugin> cryptoPlugins = new ArrayList<>();
+        CryptoKeyProviderPlugin cryptoPlugin1 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        String pluginType = UUID.randomUUID().toString();
+        Mockito.when(cryptoPlugin1.type()).thenReturn(pluginType);
+        cryptoPlugins.add(cryptoPlugin1);
+        CryptoKeyProviderPlugin cryptoPlugin2 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        Mockito.when(cryptoPlugin2.type()).thenReturn(pluginType);
+        cryptoPlugins.add(cryptoPlugin2);
+        expectThrows(IllegalArgumentException.class, () -> cryptoManagerRegistry.loadCryptoFactories(cryptoPlugins));
+    }
+
+    public void testRegistry() {
+        List<CryptoKeyProviderPlugin> cryptoPlugins = new ArrayList<>();
+        CryptoKeyProviderPlugin cryptoPlugin1 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        String pluginType1 = UUID.randomUUID().toString();
+        Mockito.when(cryptoPlugin1.type()).thenReturn(pluginType1);
+        MasterKeyProvider masterKeyProvider1 = Mockito.mock(MasterKeyProvider.class);
+        Mockito.when(cryptoPlugin1.createKeyProvider(Mockito.any())).thenReturn(masterKeyProvider1);
+        cryptoPlugins.add(cryptoPlugin1);
+
+        CryptoKeyProviderPlugin cryptoPlugin2 = Mockito.mock(CryptoKeyProviderPlugin.class);
+        String pluginType2 = UUID.randomUUID().toString();
+        Mockito.when(cryptoPlugin2.type()).thenReturn(pluginType2);
+        MasterKeyProvider masterKeyProvider2 = Mockito.mock(MasterKeyProvider.class);
+        Mockito.when(cryptoPlugin2.createKeyProvider(Mockito.any())).thenReturn(masterKeyProvider2);
+        cryptoPlugins.add(cryptoPlugin2);
+
+        Map<String, CryptoKeyProviderPlugin> loadedPlugins = cryptoManagerRegistry.loadCryptoFactories(cryptoPlugins);
+
+        CryptoKeyProviderPlugin keyProviderPlugin = loadedPlugins.get(pluginType1);
+        assertNotNull(keyProviderPlugin);
+        assertEquals(cryptoPlugin1, keyProviderPlugin);
+
+        keyProviderPlugin = loadedPlugins.get(pluginType2);
+        assertNotNull(keyProviderPlugin);
+        assertEquals(cryptoPlugin2, keyProviderPlugin);
+    }
+
+    public void testCryptoManagerMissing() {
+        String pluginName = UUID.randomUUID().toString();
+        String pluginType = UUID.randomUUID().toString();
+        CryptoMetadata cryptoMetadata = new CryptoMetadata(pluginName, pluginType, Settings.EMPTY);
+        expectThrows(CryptoRegistryException.class, () -> cryptoManagerRegistry.fetchCryptoHandler(cryptoMetadata));
+    }
+
+    public void testCryptoManagerCreationFailure() {
+        String pluginName = UUID.randomUUID().toString();
+        CryptoMetadata cryptoMetadata = new CryptoMetadata(pluginName, pluginTypeWithCreationFailure, Settings.EMPTY);
+        expectThrows(CryptoRegistryException.class, () -> cryptoManagerRegistry.fetchCryptoHandler(cryptoMetadata));
+    }
+
+    public void testCryptoManagerCreationSuccess() {
+
+        String pluginName1 = UUID.randomUUID().toString();
+        CryptoMetadata cryptoMetadata = new CryptoMetadata(pluginName1, cryptoPlugin1.type(), Settings.EMPTY);
+        CryptoHandler cryptoHandler = cryptoManagerRegistry.fetchCryptoHandler(cryptoMetadata);
+        assertNotNull(cryptoHandler);
+
+        String pluginName2 = UUID.randomUUID().toString();
+        CryptoHandler cryptoHandler2 = cryptoManagerRegistry.fetchCryptoHandler(
+            new CryptoMetadata(pluginName2, cryptoPlugin2.type(), Settings.EMPTY)
+        );
+        assertNotNull(cryptoHandler2);
+        CryptoHandler cryptoHandler3 = cryptoManagerRegistry.fetchCryptoHandler(
+            new CryptoMetadata(pluginName1, cryptoPlugin1.type(), Settings.EMPTY)
+        );
+        assertNotNull(cryptoHandler3);
+        assertEquals(cryptoHandler, cryptoHandler3);
+        assertNotEquals(cryptoHandler2, cryptoHandler);
+
+        CryptoHandler cryptoHandlerNewType = cryptoManagerRegistry.fetchCryptoHandler(
+            new CryptoMetadata(pluginName1, cryptoPlugin2.type(), Settings.EMPTY)
+        );
+        assertNotNull(cryptoHandlerNewType);
+        assertNotEquals(cryptoHandler, cryptoHandlerNewType);
+        assertNotEquals(cryptoHandler2, cryptoHandlerNewType);
+        assertNotEquals(cryptoHandler3, cryptoHandlerNewType);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/crypto/CryptoRegistryExceptionTests.java b/server/src/test/java/org/opensearch/crypto/CryptoRegistryExceptionTests.java
new file mode 100644
index 0000000000000..91f86a2b4104a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/crypto/CryptoRegistryExceptionTests.java
@@ -0,0 +1,90 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.crypto;
+
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+public class CryptoRegistryExceptionTests extends OpenSearchTestCase {
+
+    public void testConstructorWithClientNameAndType() {
+        String clientName = "test-client";
+        String clientType = "test-type";
+        CryptoRegistryException exception = new CryptoRegistryException(clientName, clientType);
+
+        assertEquals(RestStatus.NOT_FOUND, exception.status());
+        assertEquals(clientName, exception.getName());
+        assertEquals(clientType, exception.getType());
+    }
+
+    public void testConstructorWithClientNameTypeAndCause() {
+        String clientName = "test-client";
+        String clientType = "test-type";
+        String causeMessage = "Something went wrong.";
+        Throwable cause = new Throwable(causeMessage);
+        CryptoRegistryException exception = new CryptoRegistryException(clientName, clientType, cause);
+
+        assertEquals(RestStatus.INTERNAL_SERVER_ERROR, exception.status());
+        assertEquals(clientName, exception.getName());
+        assertEquals(clientType, exception.getType());
+        assertEquals(cause, exception.getCause());
+    }
+
+    public void testConstructorWithClientNameTypeAndIllegalArgsCause() {
+        String clientName = "test-client";
+        String clientType = "test-type";
+        String causeMessage = "Bad arguments.";
+        IllegalArgumentException cause = new IllegalArgumentException(causeMessage);
+        ;
+        CryptoRegistryException exception = new CryptoRegistryException(clientName, clientType, cause);
+
+        assertEquals(RestStatus.BAD_REQUEST, exception.status());
+        assertEquals(clientName, exception.getName());
+        assertEquals(clientType, exception.getType());
+        assertEquals(cause, exception.getCause());
+    }
+
+    public void testConstructorWithClientNameTypeAndCustomMessage() {
+        String clientName = "TestClient";
+        String clientType = "TestType";
+        String customMessage = "Invalid client data.";
+        CryptoRegistryException exception = new CryptoRegistryException(clientName, clientType, customMessage);
+
+        assertEquals(RestStatus.INTERNAL_SERVER_ERROR, exception.status());
+        assertEquals(clientName, exception.getName());
+        assertEquals(clientType, exception.getType());
+    }
+
+    public void testSerializationAndDeserialization() throws IOException {
+        String clientName = "TestClient";
+        String clientType = "TestType";
+        CryptoRegistryException originalException = new CryptoRegistryException(clientName, clientType);
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        StreamOutput streamOutput = new OutputStreamStreamOutput(outputStream);
+        originalException.writeTo(streamOutput);
+
+        byte[] byteArray = outputStream.toByteArray();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(byteArray);
+        StreamInput streamInput = new InputStreamStreamInput(inputStream);
+        CryptoRegistryException deserializedException = new CryptoRegistryException(streamInput);
+
+        assertEquals(originalException.getMessage(), deserializedException.getMessage());
+        assertEquals(originalException.status(), deserializedException.status());
+        assertEquals(originalException.getName(), deserializedException.getName());
+        assertEquals(originalException.getType(), deserializedException.getType());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/deps/jackson/JacksonLocationTests.java b/server/src/test/java/org/opensearch/deps/jackson/JacksonLocationTests.java
index 8da37f1e10a3a..6a57c3bf3b7ba 100644
--- a/server/src/test/java/org/opensearch/deps/jackson/JacksonLocationTests.java
+++ b/server/src/test/java/org/opensearch/deps/jackson/JacksonLocationTests.java
@@ -36,6 +36,7 @@
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonToken;
+
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/deps/lucene/VectorHighlighterTests.java b/server/src/test/java/org/opensearch/deps/lucene/VectorHighlighterTests.java
index e3a4c8a3e890d..880eaeca99bb0 100644
--- a/server/src/test/java/org/opensearch/deps/lucene/VectorHighlighterTests.java
+++ b/server/src/test/java/org/opensearch/deps/lucene/VectorHighlighterTests.java
@@ -111,7 +111,10 @@ public void testVectorHighlighterPrefixQuery() throws Exception {
         FastVectorHighlighter highlighter = new FastVectorHighlighter();
 
         PrefixQuery prefixQuery = new PrefixQuery(new Term("content", "ba"));
-        assertThat(prefixQuery.getRewriteMethod().getClass().getName(), equalTo(PrefixQuery.CONSTANT_SCORE_REWRITE.getClass().getName()));
+        assertThat(
+            prefixQuery.getRewriteMethod().getClass().getName(),
+            equalTo(PrefixQuery.CONSTANT_SCORE_BLENDED_REWRITE.getClass().getName())
+        );
         String fragment = highlighter.getBestFragment(
             highlighter.getFieldQuery(prefixQuery),
             reader,
@@ -121,14 +124,17 @@ public void testVectorHighlighterPrefixQuery() throws Exception {
         );
         assertThat(fragment, nullValue());
 
-        prefixQuery.setRewriteMethod(PrefixQuery.SCORING_BOOLEAN_REWRITE);
-        Query rewriteQuery = prefixQuery.rewrite(reader);
+        prefixQuery = new PrefixQuery(new Term("content", "ba"), PrefixQuery.SCORING_BOOLEAN_REWRITE);
+        Query rewriteQuery = prefixQuery.rewrite(searcher);
         fragment = highlighter.getBestFragment(highlighter.getFieldQuery(rewriteQuery), reader, topDocs.scoreDocs[0].doc, "content", 30);
         assertThat(fragment, notNullValue());
 
         // now check with the custom field query
         prefixQuery = new PrefixQuery(new Term("content", "ba"));
-        assertThat(prefixQuery.getRewriteMethod().getClass().getName(), equalTo(PrefixQuery.CONSTANT_SCORE_REWRITE.getClass().getName()));
+        assertThat(
+            prefixQuery.getRewriteMethod().getClass().getName(),
+            equalTo(PrefixQuery.CONSTANT_SCORE_BLENDED_REWRITE.getClass().getName())
+        );
         fragment = highlighter.getBestFragment(
             new CustomFieldQuery(prefixQuery, reader, highlighter),
             reader,
diff --git a/server/src/test/java/org/opensearch/discovery/AbstractDisruptionTestCase.java b/server/src/test/java/org/opensearch/discovery/AbstractDisruptionTestCase.java
index 5a61300caa89e..d5e51efbb534f 100644
--- a/server/src/test/java/org/opensearch/discovery/AbstractDisruptionTestCase.java
+++ b/server/src/test/java/org/opensearch/discovery/AbstractDisruptionTestCase.java
@@ -44,9 +44,9 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.index.IndexService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.disruption.NetworkDisruption;
 import org.opensearch.test.disruption.NetworkDisruption.Bridge;
 import org.opensearch.test.disruption.NetworkDisruption.DisruptedLinks;
@@ -155,19 +155,22 @@ ClusterState getNodeClusterState(String node) {
         return client(node).admin().cluster().prepareState().setLocal(true).get().getState();
     }
 
-    void assertNoMaster(final String node) throws Exception {
-        assertNoMaster(node, null, TimeValue.timeValueSeconds(30));
+    void assertNoClusterManager(final String node) throws Exception {
+        assertNoClusterManager(node, null, TimeValue.timeValueSeconds(30));
     }
 
-    void assertNoMaster(final String node, TimeValue maxWaitTime) throws Exception {
-        assertNoMaster(node, null, maxWaitTime);
+    void assertNoClusterManager(final String node, TimeValue maxWaitTime) throws Exception {
+        assertNoClusterManager(node, null, maxWaitTime);
     }
 
-    void assertNoMaster(final String node, @Nullable final ClusterBlock expectedBlocks, TimeValue maxWaitTime) throws Exception {
+    void assertNoClusterManager(final String node, @Nullable final ClusterBlock expectedBlocks, TimeValue maxWaitTime) throws Exception {
         assertBusy(() -> {
             ClusterState state = getNodeClusterState(node);
             final DiscoveryNodes nodes = state.nodes();
-            assertNull("node [" + node + "] still has [" + nodes.getMasterNode() + "] as master", nodes.getMasterNode());
+            assertNull(
+                "node [" + node + "] still has [" + nodes.getClusterManagerNode() + "] as cluster-manager",
+                nodes.getClusterManagerNode()
+            );
             if (expectedBlocks != null) {
                 for (ClusterBlockLevel level : expectedBlocks.levels()) {
                     assertTrue(
@@ -179,26 +182,36 @@ void assertNoMaster(final String node, @Nullable final ClusterBlock expectedBloc
         }, maxWaitTime.getMillis(), TimeUnit.MILLISECONDS);
     }
 
-    void assertDifferentMaster(final String node, final String oldMasterNode) throws Exception {
+    void assertDifferentClusterManager(final String node, final String oldClusterManagerNode) throws Exception {
         assertBusy(() -> {
             ClusterState state = getNodeClusterState(node);
-            String masterNode = null;
-            if (state.nodes().getMasterNode() != null) {
-                masterNode = state.nodes().getMasterNode().getName();
+            String clusterManagerNode = null;
+            if (state.nodes().getClusterManagerNode() != null) {
+                clusterManagerNode = state.nodes().getClusterManagerNode().getName();
             }
-            logger.trace("[{}] master is [{}]", node, state.nodes().getMasterNode());
-            assertThat("node [" + node + "] still has [" + masterNode + "] as master", oldMasterNode, not(equalTo(masterNode)));
+            logger.trace("[{}] cluster-manager is [{}]", node, state.nodes().getClusterManagerNode());
+            assertThat(
+                "node [" + node + "] still has [" + clusterManagerNode + "] as cluster-manager",
+                oldClusterManagerNode,
+                not(equalTo(clusterManagerNode))
+            );
         }, 30, TimeUnit.SECONDS);
     }
 
-    void assertMaster(String masterNode, List<String> nodes) throws Exception {
+    void assertClusterManager(String clusterManagerNode, List<String> nodes) throws Exception {
         assertBusy(() -> {
             for (String node : nodes) {
                 ClusterState state = getNodeClusterState(node);
                 String failMsgSuffix = "cluster_state:\n" + state;
                 assertThat("wrong node count on [" + node + "]. " + failMsgSuffix, state.nodes().getSize(), equalTo(nodes.size()));
-                String otherMasterNodeName = state.nodes().getMasterNode() != null ? state.nodes().getMasterNode().getName() : null;
-                assertThat("wrong master on node [" + node + "]. " + failMsgSuffix, otherMasterNodeName, equalTo(masterNode));
+                String otherClusterManagerNodeName = state.nodes().getClusterManagerNode() != null
+                    ? state.nodes().getClusterManagerNode().getName()
+                    : null;
+                assertThat(
+                    "wrong cluster-manager on node [" + node + "]. " + failMsgSuffix,
+                    otherClusterManagerNodeName,
+                    equalTo(clusterManagerNode)
+                );
             }
         });
     }
diff --git a/server/src/test/java/org/opensearch/discovery/DiscoveryModuleTests.java b/server/src/test/java/org/opensearch/discovery/DiscoveryModuleTests.java
index d1e3f406b4933..b33ebf8333b36 100644
--- a/server/src/test/java/org/opensearch/discovery/DiscoveryModuleTests.java
+++ b/server/src/test/java/org/opensearch/discovery/DiscoveryModuleTests.java
@@ -34,18 +34,21 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.Coordinator;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.service.ClusterApplier;
-import org.opensearch.cluster.service.MasterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.gateway.GatewayMetaState;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.plugins.DiscoveryPlugin;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
@@ -70,12 +73,14 @@ public class DiscoveryModuleTests extends OpenSearchTestCase {
 
     private TransportService transportService;
     private NamedWriteableRegistry namedWriteableRegistry;
-    private MasterService masterService;
+    private ClusterManagerService clusterManagerService;
     private ClusterApplier clusterApplier;
     private ThreadPool threadPool;
     private ClusterSettings clusterSettings;
     private GatewayMetaState gatewayMetaState;
 
+    private RemoteStoreNodeService remoteStoreNodeService;
+
     public interface DummyHostsProviderPlugin extends DiscoveryPlugin {
         Map<String, Supplier<SeedHostsProvider>> impl();
 
@@ -92,12 +97,13 @@ default Map<String, Supplier<SeedHostsProvider>> getSeedHostProviders(
     public void setupDummyServices() {
         threadPool = mock(ThreadPool.class);
         when(threadPool.getThreadContext()).thenReturn(new ThreadContext(Settings.EMPTY));
-        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null);
-        masterService = mock(MasterService.class);
+        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, NoopTracer.INSTANCE);
+        clusterManagerService = mock(ClusterManagerService.class);
         namedWriteableRegistry = new NamedWriteableRegistry(Collections.emptyList());
         clusterApplier = mock(ClusterApplier.class);
         clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
         gatewayMetaState = mock(GatewayMetaState.class);
+        remoteStoreNodeService = mock(RemoteStoreNodeService.class);
     }
 
     @After
@@ -112,7 +118,7 @@ private DiscoveryModule newModule(Settings settings, List<DiscoveryPlugin> plugi
             transportService,
             namedWriteableRegistry,
             null,
-            masterService,
+            clusterManagerService,
             clusterApplier,
             clusterSettings,
             plugins,
@@ -120,7 +126,9 @@ private DiscoveryModule newModule(Settings settings, List<DiscoveryPlugin> plugi
             createTempDir().toAbsolutePath(),
             gatewayMetaState,
             mock(RerouteService.class),
-            null
+            null,
+            new PersistedStateRegistry(),
+            remoteStoreNodeService
         );
     }
 
@@ -218,10 +226,9 @@ public void testMultipleSeedsProviders() {
     }
 
     public void testLazyConstructionSeedsProvider() {
-        DummyHostsProviderPlugin plugin = () -> Collections.singletonMap(
-            "custom",
-            () -> { throw new AssertionError("created hosts provider which was not selected"); }
-        );
+        DummyHostsProviderPlugin plugin = () -> Collections.singletonMap("custom", () -> {
+            throw new AssertionError("created hosts provider which was not selected");
+        });
         newModule(Settings.EMPTY, Collections.singletonList(plugin));
     }
 
diff --git a/server/src/test/java/org/opensearch/discovery/FileBasedSeedHostsProviderTests.java b/server/src/test/java/org/opensearch/discovery/FileBasedSeedHostsProviderTests.java
index ad6b3de3d3243..f4515361a89b8 100644
--- a/server/src/test/java/org/opensearch/discovery/FileBasedSeedHostsProviderTests.java
+++ b/server/src/test/java/org/opensearch/discovery/FileBasedSeedHostsProviderTests.java
@@ -33,15 +33,16 @@
 package org.opensearch.discovery;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -99,7 +100,8 @@ private void createTransportSvc() {
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public BoundTransportAddress boundAddress() {
@@ -114,7 +116,8 @@ public BoundTransportAddress boundAddress() {
             transport,
             threadPool,
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
-            null
+            null,
+            NoopTracer.INSTANCE
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java b/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
index 403d2e2122855..0d694bcfa135b 100644
--- a/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
+++ b/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
@@ -35,17 +35,18 @@
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -122,7 +123,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             address -> localNode,
             null,
-            emptySet()
+            emptySet(),
+            NoopTracer.INSTANCE
         );
 
         transportService.start();
@@ -137,7 +139,7 @@ public void stopServices() {
         terminate(threadPool);
     }
 
-    public void testConnectsToMasterNode() throws InterruptedException {
+    public void testConnectsToClustreManagerNode() throws InterruptedException {
         final CountDownLatch completionLatch = new CountDownLatch(1);
         final SetOnce<DiscoveryNode> receivedNode = new SetOnce<>();
 
@@ -190,7 +192,7 @@ public void testLogsFullConnectionFailureAfterSuccessfulHandshake() throws Excep
         }
     }
 
-    public void testDoesNotConnectToNonMasterNode() throws InterruptedException {
+    public void testDoesNotConnectToNonClusterManagerNode() throws InterruptedException {
         remoteNode = new DiscoveryNode("remote-node", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         discoveryAddress = getDiscoveryAddress();
         remoteClusterName = "local-cluster";
diff --git a/server/src/test/java/org/opensearch/discovery/InitializeExtensionRequestTests.java b/server/src/test/java/org/opensearch/discovery/InitializeExtensionRequestTests.java
new file mode 100644
index 0000000000000..ca94a3b52a56c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/discovery/InitializeExtensionRequestTests.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.discovery;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.ExtensionDependency;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.net.InetAddress;
+import java.util.HashMap;
+import java.util.List;
+
+public class InitializeExtensionRequestTests extends OpenSearchTestCase {
+
+    public void testInitializeExtensionRequest() throws Exception {
+        String expectedUniqueId = "test uniqueid";
+        Version expectedVersion = Version.fromString("2.0.0");
+        ExtensionDependency expectedDependency = new ExtensionDependency(expectedUniqueId, expectedVersion);
+        DiscoveryExtensionNode expectedExtensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<>(),
+            Version.CURRENT,
+            Version.CURRENT,
+            List.of(expectedDependency)
+        );
+        DiscoveryNode expectedSourceNode = new DiscoveryNode(
+            "sourceNode",
+            "uniqueid2",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 1000),
+            new HashMap<>(),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        InitializeExtensionRequest initializeExtensionRequest = new InitializeExtensionRequest(expectedSourceNode, expectedExtensionNode);
+        assertEquals(expectedExtensionNode, initializeExtensionRequest.getExtension());
+        assertEquals(expectedSourceNode, initializeExtensionRequest.getSourceNode());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            initializeExtensionRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                initializeExtensionRequest = new InitializeExtensionRequest(in);
+
+                assertEquals(expectedExtensionNode, initializeExtensionRequest.getExtension());
+                assertEquals(expectedSourceNode, initializeExtensionRequest.getSourceNode());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/discovery/InitializeExtensionResponseTests.java b/server/src/test/java/org/opensearch/discovery/InitializeExtensionResponseTests.java
new file mode 100644
index 0000000000000..2cc42957cf120
--- /dev/null
+++ b/server/src/test/java/org/opensearch/discovery/InitializeExtensionResponseTests.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.discovery;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class InitializeExtensionResponseTests extends OpenSearchTestCase {
+    public void testInitializeExtensionResponse() throws Exception {
+        String expectedName = "testsample-sdk";
+        List<String> expectedImplementedInterfaces = new ArrayList<>(Arrays.asList("Action", "Search"));
+
+        InitializeExtensionResponse initializeExtensionResponse = new InitializeExtensionResponse(
+            expectedName,
+            expectedImplementedInterfaces
+        );
+
+        assertEquals(expectedName, initializeExtensionResponse.getName());
+        List<String> implementedInterfaces = initializeExtensionResponse.getImplementedInterfaces();
+        assertEquals(expectedImplementedInterfaces.size(), implementedInterfaces.size());
+        assertTrue(implementedInterfaces.containsAll(expectedImplementedInterfaces));
+        assertTrue(expectedImplementedInterfaces.containsAll(implementedInterfaces));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            initializeExtensionResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                initializeExtensionResponse = new InitializeExtensionResponse(in);
+
+                assertEquals(expectedName, initializeExtensionResponse.getName());
+                implementedInterfaces = initializeExtensionResponse.getImplementedInterfaces();
+                assertEquals(expectedImplementedInterfaces.size(), implementedInterfaces.size());
+                assertTrue(implementedInterfaces.containsAll(expectedImplementedInterfaces));
+                assertTrue(expectedImplementedInterfaces.containsAll(implementedInterfaces));
+            }
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/discovery/PeerFinderMessagesTests.java b/server/src/test/java/org/opensearch/discovery/PeerFinderMessagesTests.java
index a274760872e88..3e6786baf91ef 100644
--- a/server/src/test/java/org/opensearch/discovery/PeerFinderMessagesTests.java
+++ b/server/src/test/java/org/opensearch/discovery/PeerFinderMessagesTests.java
@@ -35,9 +35,9 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.coordination.PeersResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -97,12 +97,12 @@ public void testPeersResponseEqualsHashCodeSerialization() {
                 final long term = in.getTerm();
                 if (randomBoolean()) {
                     return new PeersResponse(
-                        in.getMasterNode(),
+                        in.getClusterManagerNode(),
                         in.getKnownPeers(),
                         randomValueOtherThan(term, OpenSearchTestCase::randomNonNegativeLong)
                     );
                 } else {
-                    if (in.getMasterNode().isPresent()) {
+                    if (in.getClusterManagerNode().isPresent()) {
                         if (randomBoolean()) {
                             return new PeersResponse(Optional.of(createNode(randomAlphaOfLength(10))), in.getKnownPeers(), term);
                         } else {
@@ -112,7 +112,7 @@ public void testPeersResponseEqualsHashCodeSerialization() {
                         if (randomBoolean()) {
                             return new PeersResponse(Optional.of(createNode(randomAlphaOfLength(10))), emptyList(), term);
                         } else {
-                            return new PeersResponse(in.getMasterNode(), modifyDiscoveryNodesList(in.getKnownPeers(), false), term);
+                            return new PeersResponse(in.getClusterManagerNode(), modifyDiscoveryNodesList(in.getKnownPeers(), false), term);
                         }
                     }
                 }
diff --git a/server/src/test/java/org/opensearch/discovery/PeerFinderTests.java b/server/src/test/java/org/opensearch/discovery/PeerFinderTests.java
index 6558f9d06c2f7..f861ab90896db 100644
--- a/server/src/test/java/org/opensearch/discovery/PeerFinderTests.java
+++ b/server/src/test/java/org/opensearch/discovery/PeerFinderTests.java
@@ -34,16 +34,17 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.coordination.PeersResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.PeerFinder.TransportAddressConnector;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.test.transport.CapturingTransport.CapturedRequest;
@@ -140,14 +141,14 @@ public void run() {
                     for (final Map.Entry<TransportAddress, DiscoveryNode> addressAndNode : reachableNodes.entrySet()) {
                         if (addressAndNode.getKey().equals(transportAddress)) {
                             final DiscoveryNode discoveryNode = addressAndNode.getValue();
-                            if (discoveryNode.isMasterNode()) {
+                            if (discoveryNode.isClusterManagerNode()) {
                                 disconnectedNodes.remove(discoveryNode);
                                 connectedNodes.add(discoveryNode);
                                 assertTrue(inFlightConnectionAttempts.remove(transportAddress));
                                 listener.onResponse(discoveryNode);
                                 return;
                             } else {
-                                listener.onFailure(new OpenSearchException("non-master node " + discoveryNode));
+                                listener.onFailure(new OpenSearchException("non-cluster-manager node " + discoveryNode));
                                 return;
                             }
                         }
@@ -165,20 +166,20 @@ public String toString() {
     }
 
     class TestPeerFinder extends PeerFinder {
-        DiscoveryNode discoveredMasterNode;
-        OptionalLong discoveredMasterTerm = OptionalLong.empty();
+        DiscoveryNode discoveredClusterManagerNode;
+        OptionalLong discoveredClusterManagerTerm = OptionalLong.empty();
 
         TestPeerFinder(Settings settings, TransportService transportService, TransportAddressConnector transportAddressConnector) {
             super(settings, transportService, transportAddressConnector, PeerFinderTests.this::resolveConfiguredHosts);
         }
 
         @Override
-        protected void onActiveMasterFound(DiscoveryNode masterNode, long term) {
+        protected void onActiveClusterManagerFound(DiscoveryNode clusterManagerNode, long term) {
             assert holdsLock() == false : "PeerFinder lock held in error";
-            assertThat(discoveredMasterNode, nullValue());
-            assertFalse(discoveredMasterTerm.isPresent());
-            discoveredMasterNode = masterNode;
-            discoveredMasterTerm = OptionalLong.of(term);
+            assertThat(discoveredClusterManagerNode, nullValue());
+            assertFalse(discoveredClusterManagerTerm.isPresent());
+            discoveredClusterManagerNode = clusterManagerNode;
+            discoveredClusterManagerTerm = OptionalLong.of(term);
         }
 
         @Override
@@ -242,7 +243,8 @@ public void setup() {
             boundTransportAddress -> localNode,
             null,
             emptySet(),
-            connectionManager
+            connectionManager,
+            NoopTracer.INSTANCE
         );
 
         transportService.start();
@@ -335,8 +337,8 @@ public void testDoesNotAddUnreachableNodesFromUnicastHostsList() {
         assertFoundPeers();
     }
 
-    public void testDoesNotAddNonMasterEligibleNodesFromUnicastHostsList() {
-        final DiscoveryNode nonMasterNode = new DiscoveryNode(
+    public void testDoesNotAddNonClusterManagerEligibleNodesFromUnicastHostsList() {
+        final DiscoveryNode nonClusterManagerNode = new DiscoveryNode(
             "node-from-hosts-list",
             buildNewFakeTransportAddress(),
             emptyMap(),
@@ -344,8 +346,8 @@ public void testDoesNotAddNonMasterEligibleNodesFromUnicastHostsList() {
             Version.CURRENT
         );
 
-        providedAddresses.add(nonMasterNode.getAddress());
-        transportAddressConnector.addReachableNode(nonMasterNode);
+        providedAddresses.add(nonClusterManagerNode.getAddress());
+        transportAddressConnector.addReachableNode(nonClusterManagerNode);
 
         peerFinder.activate(lastAcceptedNodes);
         runAllRunnableTasks();
@@ -423,7 +425,7 @@ public void testAddsReachableNodesFromIncomingRequests() {
         assertFoundPeers(sourceNode, otherKnownNode);
     }
 
-    public void testDoesNotAddReachableNonMasterEligibleNodesFromIncomingRequests() {
+    public void testDoesNotAddReachableNonClusterManagerEligibleNodesFromIncomingRequests() {
         final DiscoveryNode sourceNode = new DiscoveryNode(
             "request-source",
             buildNewFakeTransportAddress(),
@@ -477,7 +479,7 @@ public void testRespondsToRequestWhenActive() {
 
         peerFinder.activate(lastAcceptedNodes);
         final PeersResponse peersResponse1 = peerFinder.handlePeersRequest(new PeersRequest(sourceNode, Collections.emptyList()));
-        assertFalse(peersResponse1.getMasterNode().isPresent());
+        assertFalse(peersResponse1.getClusterManagerNode().isPresent());
         assertThat(peersResponse1.getKnownPeers(), empty()); // sourceNode is not yet known
         assertThat(peersResponse1.getTerm(), is(0L));
 
@@ -488,13 +490,13 @@ public void testRespondsToRequestWhenActive() {
         final long updatedTerm = randomNonNegativeLong();
         peerFinder.setCurrentTerm(updatedTerm);
         final PeersResponse peersResponse2 = peerFinder.handlePeersRequest(new PeersRequest(sourceNode, Collections.emptyList()));
-        assertFalse(peersResponse2.getMasterNode().isPresent());
+        assertFalse(peersResponse2.getClusterManagerNode().isPresent());
         assertThat(peersResponse2.getKnownPeers(), contains(sourceNode));
         assertThat(peersResponse2.getTerm(), is(updatedTerm));
     }
 
     public void testDelegatesRequestHandlingWhenInactive() {
-        final DiscoveryNode masterNode = newDiscoveryNode("master-node");
+        final DiscoveryNode clusterManagerNode = newDiscoveryNode("cluster-manager-node");
         final DiscoveryNode sourceNode = newDiscoveryNode("request-source");
         transportAddressConnector.addReachableNode(sourceNode);
 
@@ -502,9 +504,9 @@ public void testDelegatesRequestHandlingWhenInactive() {
 
         final long term = randomNonNegativeLong();
         peerFinder.setCurrentTerm(term);
-        peerFinder.deactivate(masterNode);
+        peerFinder.deactivate(clusterManagerNode);
 
-        final PeersResponse expectedResponse = new PeersResponse(Optional.of(masterNode), Collections.emptyList(), term);
+        final PeersResponse expectedResponse = new PeersResponse(Optional.of(clusterManagerNode), Collections.emptyList(), term);
         final PeersResponse peersResponse = peerFinder.handlePeersRequest(new PeersRequest(sourceNode, Collections.emptyList()));
         assertThat(peersResponse, equalTo(expectedResponse));
     }
@@ -531,7 +533,7 @@ public PeersResponse read(StreamInput in) throws IOException {
                 @Override
                 public void handleResponse(PeersResponse response) {
                     assertTrue(responseReceived.compareAndSet(false, true));
-                    assertFalse(response.getMasterNode().isPresent());
+                    assertFalse(response.getClusterManagerNode().isPresent());
                     assertThat(response.getKnownPeers(), empty()); // sourceNode is not yet known
                     assertThat(response.getTerm(), is(0L));
                 }
@@ -590,7 +592,7 @@ public void testAddsReachablePeersFromResponse() {
         assertFoundPeers(otherNode, discoveredNode);
     }
 
-    public void testAddsReachableMasterFromResponse() {
+    public void testAddsReachableClusterManagerFromResponse() {
         final DiscoveryNode otherNode = newDiscoveryNode("node-from-hosts-list");
         providedAddresses.add(otherNode.getAddress());
         transportAddressConnector.addReachableNode(otherNode);
@@ -599,21 +601,21 @@ public void testAddsReachableMasterFromResponse() {
         runAllRunnableTasks();
 
         assertFoundPeers(otherNode);
-        final DiscoveryNode discoveredMaster = newDiscoveryNode("discovered-master");
+        final DiscoveryNode discoveredClusterManager = newDiscoveryNode("discovered-cluster-manager");
 
         respondToRequests(node -> {
             assertThat(node, is(otherNode));
-            return new PeersResponse(Optional.of(discoveredMaster), emptyList(), randomNonNegativeLong());
+            return new PeersResponse(Optional.of(discoveredClusterManager), emptyList(), randomNonNegativeLong());
         });
 
-        transportAddressConnector.addReachableNode(discoveredMaster);
+        transportAddressConnector.addReachableNode(discoveredClusterManager);
         runAllRunnableTasks();
-        assertFoundPeers(otherNode, discoveredMaster);
-        assertThat(peerFinder.discoveredMasterNode, nullValue());
-        assertFalse(peerFinder.discoveredMasterTerm.isPresent());
+        assertFoundPeers(otherNode, discoveredClusterManager);
+        assertThat(peerFinder.discoveredClusterManagerNode, nullValue());
+        assertFalse(peerFinder.discoveredClusterManagerTerm.isPresent());
     }
 
-    public void testHandlesDiscoveryOfMasterFromResponseFromMaster() {
+    public void testHandlesDiscoveryOfClusterManagerFromResponseFromClusterManager() {
         final DiscoveryNode otherNode = newDiscoveryNode("node-from-hosts-list");
         providedAddresses.add(otherNode.getAddress());
         transportAddressConnector.addReachableNode(otherNode);
@@ -631,8 +633,8 @@ public void testHandlesDiscoveryOfMasterFromResponseFromMaster() {
 
         runAllRunnableTasks();
         assertFoundPeers(otherNode);
-        assertThat(peerFinder.discoveredMasterNode, is(otherNode));
-        assertThat(peerFinder.discoveredMasterTerm, is(OptionalLong.of(term)));
+        assertThat(peerFinder.discoveredClusterManagerNode, is(otherNode));
+        assertThat(peerFinder.discoveredClusterManagerTerm, is(OptionalLong.of(term)));
     }
 
     public void testOnlyRequestsPeersOncePerRoundButDoesRetryNextRound() {
@@ -807,6 +809,42 @@ public void testReconnectsToDisconnectedNodes() {
         assertFoundPeers(rebootedOtherNode);
     }
 
+    public void testConnectionAttemptDuringDecommissioning() {
+        boolean localNodeCommissioned = randomBoolean();
+        peerFinder.onNodeCommissionStatusChange(localNodeCommissioned);
+
+        long findPeersInterval = peerFinder.getFindPeersInterval().millis();
+
+        final DiscoveryNode otherNode = newDiscoveryNode("node-1");
+        providedAddresses.add(otherNode.getAddress());
+        transportAddressConnector.addReachableNode(otherNode);
+
+        peerFinder.activate(lastAcceptedNodes);
+        runAllRunnableTasks();
+        assertFoundPeers(otherNode);
+
+        transportAddressConnector.reachableNodes.clear();
+        final DiscoveryNode newNode = new DiscoveryNode("new-node", otherNode.getAddress(), Version.CURRENT);
+        transportAddressConnector.addReachableNode(newNode);
+
+        connectedNodes.remove(otherNode);
+        disconnectedNodes.add(otherNode);
+
+        // peer discovery will be delayed now
+        if (localNodeCommissioned == false) {
+            deterministicTaskQueue.advanceTime();
+            runAllRunnableTasks();
+            assertPeersNotDiscovered(newNode);
+        }
+
+        final long expectedTime = CONNECTION_TIMEOUT_MILLIS + findPeersInterval;
+        while (deterministicTaskQueue.getCurrentTimeMillis() < expectedTime) {
+            deterministicTaskQueue.advanceTime();
+            runAllRunnableTasks();
+        }
+        assertFoundPeers(newNode);
+    }
+
     private void respondToRequests(Function<DiscoveryNode, PeersResponse> responseFactory) {
         final CapturedRequest[] capturedRequests = capturingTransport.getCapturedRequestsAndClear();
         for (final CapturedRequest capturedRequest : capturedRequests) {
@@ -828,6 +866,16 @@ private void assertFoundPeers(DiscoveryNode... expectedNodesArray) {
         assertNotifiedOfAllUpdates();
     }
 
+    private void assertPeersNotDiscovered(DiscoveryNode... undiscoveredNodesArray) {
+        final Set<DiscoveryNode> undiscoveredNodes = Arrays.stream(undiscoveredNodesArray).collect(Collectors.toSet());
+        final List<DiscoveryNode> actualNodesList = StreamSupport.stream(peerFinder.getFoundPeers().spliterator(), false)
+            .collect(Collectors.toList());
+        final HashSet<DiscoveryNode> actualNodesSet = new HashSet<>(actualNodesList);
+        Set<DiscoveryNode> intersection = new HashSet<>(actualNodesSet);
+        intersection.retainAll(undiscoveredNodes);
+        assertEquals(intersection.size(), 0);
+    }
+
     private void assertNotifiedOfAllUpdates() {
         final Stream<DiscoveryNode> actualNodes = StreamSupport.stream(peerFinder.getFoundPeers().spliterator(), false);
         final Stream<DiscoveryNode> notifiedNodes = StreamSupport.stream(foundPeersFromNotification.spliterator(), false);
diff --git a/server/src/test/java/org/opensearch/discovery/SeedHostsResolverTests.java b/server/src/test/java/org/opensearch/discovery/SeedHostsResolverTests.java
index 53e7f59460e47..421f6c6fe279b 100644
--- a/server/src/test/java/org/opensearch/discovery/SeedHostsResolverTests.java
+++ b/server/src/test/java/org/opensearch/discovery/SeedHostsResolverTests.java
@@ -35,19 +35,20 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.FutureUtils;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -56,7 +57,6 @@
 import org.opensearch.transport.nio.MockNioTransport;
 import org.junit.After;
 import org.junit.Before;
-import org.mockito.Mockito;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -77,6 +77,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
@@ -183,7 +185,8 @@ public void testRemovingLocalAddresses() {
             networkService,
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -202,7 +205,8 @@ public BoundTransportAddress boundAddress() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         closeables.push(transportService);
         final List<TransportAddress> transportAddresses = SeedHostsResolver.resolveHostsLists(
@@ -234,7 +238,8 @@ public void testUnknownHost() {
             networkService,
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -260,7 +265,8 @@ public TransportAddress[] addressesFromString(String address) throws UnknownHost
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         closeables.push(transportService);
 
@@ -288,7 +294,8 @@ public void testResolveTimeout() {
             networkService,
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -325,7 +332,8 @@ public TransportAddress[] addressesFromString(String address) throws UnknownHost
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         closeables.push(transportService);
         final TimeValue resolveTimeout = TimeValue.timeValueSeconds(randomIntBetween(3, 5));
@@ -363,7 +371,8 @@ public void testCancellationOnClose() throws InterruptedException {
             networkService,
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
@@ -401,7 +410,8 @@ public TransportAddress[] addressesFromString(String address) throws UnknownHost
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         closeables.push(transportService);
         recreateSeedHostsResolver(
@@ -426,7 +436,8 @@ public void testInvalidHosts() throws IllegalAccessException {
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
             @Override
             public BoundTransportAddress boundAddress() {
@@ -445,7 +456,8 @@ public BoundTransportAddress boundAddress() {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             x -> null,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         closeables.push(transportService);
         final List<TransportAddress> transportAddresses = SeedHostsResolver.resolveHostsLists(
diff --git a/server/src/test/java/org/opensearch/discovery/SettingsBasedSeedHostsProviderTests.java b/server/src/test/java/org/opensearch/discovery/SettingsBasedSeedHostsProviderTests.java
index 4648c98bec5df..9a828e6708d41 100644
--- a/server/src/test/java/org/opensearch/discovery/SettingsBasedSeedHostsProviderTests.java
+++ b/server/src/test/java/org/opensearch/discovery/SettingsBasedSeedHostsProviderTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.discovery;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.discovery.SeedHostsProvider.HostsResolver;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.TransportService;
diff --git a/server/src/test/java/org/opensearch/env/NodeEnvironmentTests.java b/server/src/test/java/org/opensearch/env/NodeEnvironmentTests.java
index 6f07d0de1e31d..3378d9e0dae8b 100644
--- a/server/src/test/java/org/opensearch/env/NodeEnvironmentTests.java
+++ b/server/src/test/java/org/opensearch/env/NodeEnvironmentTests.java
@@ -39,16 +39,16 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.Node;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
 import org.opensearch.test.NodeRoles;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -65,8 +65,8 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.Matchers.arrayWithSize;
 import static org.hamcrest.Matchers.containsString;
@@ -473,7 +473,7 @@ public void testCustomDataPaths() throws Exception {
     public void testNodeIdNotPersistedAtInitialization() throws IOException {
         NodeEnvironment env = newNodeEnvironment(
             new String[0],
-            nonMasterNode(nonDataNode(Settings.builder().put("node.local_storage", false).build()))
+            nonClusterManagerNode(nonDataNode(Settings.builder().put("node.local_storage", false).build()))
         );
         String nodeID = env.nodeId();
         env.close();
@@ -524,8 +524,8 @@ public void testEnsureNoShardDataOrIndexMetadata() throws IOException {
         Settings settings = buildEnvSettings(Settings.EMPTY);
         Index index = new Index("test", "testUUID");
 
-        // build settings using same path.data as original but without data and master roles
-        Settings noDataNoMasterSettings = Settings.builder()
+        // build settings using same path.data as original but without data and cluster-manager roles
+        Settings noDataNoClusterManagerSettings = Settings.builder()
             .put(settings)
             .put(
                 NodeRoles.removeRoles(
@@ -535,8 +535,8 @@ public void testEnsureNoShardDataOrIndexMetadata() throws IOException {
             )
             .build();
 
-        // test that we can create data=false and master=false with no meta information
-        newNodeEnvironment(noDataNoMasterSettings).close();
+        // test that we can create data=false and cluster_manager=false with no meta information
+        newNodeEnvironment(noDataNoClusterManagerSettings).close();
 
         Path indexPath;
         try (NodeEnvironment env = newNodeEnvironment(settings)) {
@@ -546,7 +546,7 @@ public void testEnsureNoShardDataOrIndexMetadata() throws IOException {
             indexPath = env.indexPaths(index)[0];
         }
 
-        verifyFailsOnMetadata(noDataNoMasterSettings, indexPath);
+        verifyFailsOnMetadata(noDataNoClusterManagerSettings, indexPath);
 
         // build settings using same path.data as original but without data role
         Settings noDataSettings = nonDataNode(settings);
@@ -563,15 +563,15 @@ public void testEnsureNoShardDataOrIndexMetadata() throws IOException {
         verifyFailsOnShardData(noDataSettings, indexPath, shardDataDirName);
 
         // assert that we get the stricter message on meta-data when both conditions fail
-        verifyFailsOnMetadata(noDataNoMasterSettings, indexPath);
+        verifyFailsOnMetadata(noDataNoClusterManagerSettings, indexPath);
 
-        // build settings using same path.data as original but without master role
-        Settings noMasterSettings = nonMasterNode(settings);
+        // build settings using same path.data as original but without cluster-manager role
+        Settings noClusterManagerSettings = nonClusterManagerNode(settings);
 
-        // test that we can create master=false env regardless of data.
-        newNodeEnvironment(noMasterSettings).close();
+        // test that we can create cluster_manager=false env regardless of data.
+        newNodeEnvironment(noClusterManagerSettings).close();
 
-        // test that we can create data=true, master=true env. Also remove state dir to leave only shard data for following asserts
+        // test that we can create data=true, cluster_manager=true env. Also remove state dir to leave only shard data for following asserts
         try (NodeEnvironment env = newNodeEnvironment(settings)) {
             for (Path path : env.indexPaths(index)) {
                 Files.delete(path.resolve(MetadataStateFormat.STATE_DIR_NAME));
@@ -580,7 +580,7 @@ public void testEnsureNoShardDataOrIndexMetadata() throws IOException {
 
         // assert that we fail on shard data even without the metadata dir.
         verifyFailsOnShardData(noDataSettings, indexPath, shardDataDirName);
-        verifyFailsOnShardData(noDataNoMasterSettings, indexPath, shardDataDirName);
+        verifyFailsOnShardData(noDataNoClusterManagerSettings, indexPath, shardDataDirName);
     }
 
     private void verifyFailsOnShardData(Settings settings, Path indexPath, String shardDataDirName) {
@@ -597,7 +597,7 @@ private void verifyFailsOnShardData(Settings settings, Path indexPath, String sh
     private void verifyFailsOnMetadata(Settings settings, Path indexPath) {
         IllegalStateException ex = expectThrows(
             IllegalStateException.class,
-            "Must fail creating NodeEnvironment on a data path that has index metadata if node does not have data and master roles",
+            "Must fail creating NodeEnvironment on a data path that has index metadata if node does not have data and cluster-manager roles",
             () -> newNodeEnvironment(settings).close()
         );
 
diff --git a/server/src/test/java/org/opensearch/env/NodeMetadataTests.java b/server/src/test/java/org/opensearch/env/NodeMetadataTests.java
index cd3b9c6205220..8e038f91c64d4 100644
--- a/server/src/test/java/org/opensearch/env/NodeMetadataTests.java
+++ b/server/src/test/java/org/opensearch/env/NodeMetadataTests.java
@@ -35,8 +35,8 @@
 import org.opensearch.Version;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.gateway.MetadataStateFormat;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/env/NodeRepurposeCommandTests.java b/server/src/test/java/org/opensearch/env/NodeRepurposeCommandTests.java
index 9897ad1a3650b..2a3525143c01f 100644
--- a/server/src/test/java/org/opensearch/env/NodeRepurposeCommandTests.java
+++ b/server/src/test/java/org/opensearch/env/NodeRepurposeCommandTests.java
@@ -47,8 +47,10 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
 import org.opensearch.gateway.PersistedClusterStateService;
-import org.opensearch.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matcher;
 import org.junit.Before;
@@ -57,16 +59,19 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashSet;
+import java.util.Set;
 import java.util.stream.Stream;
 
 import static org.opensearch.env.NodeRepurposeCommand.NO_CLEANUP;
 import static org.opensearch.env.NodeRepurposeCommand.NO_DATA_TO_CLEAN_UP_FOUND;
+import static org.opensearch.env.NodeRepurposeCommand.NO_FILE_CACHE_DATA_TO_CLEAN_UP_FOUND;
 import static org.opensearch.env.NodeRepurposeCommand.NO_SHARD_DATA_TO_CLEAN_UP_FOUND;
-import static org.opensearch.test.NodeRoles.masterNode;
+import static org.opensearch.node.Node.NODE_SEARCH_CACHE_SIZE_SETTING;
+import static org.opensearch.test.NodeRoles.addRoles;
+import static org.opensearch.test.NodeRoles.clusterManagerNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.onlyRole;
 import static org.opensearch.test.NodeRoles.removeRoles;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.containsString;
@@ -75,18 +80,38 @@
 public class NodeRepurposeCommandTests extends OpenSearchTestCase {
 
     private static final Index INDEX = new Index("testIndex", "testUUID");
-    private Settings dataMasterSettings;
+    private Settings dataClusterManagerSettings;
+    private Settings dataSearchClusterManagerSettings;
     private Environment environment;
     private Path[] nodePaths;
-    private Settings dataNoMasterSettings;
-    private Settings noDataNoMasterSettings;
-    private Settings noDataMasterSettings;
+    private Settings dataSearchNoClusterManagerSettings;
+    private Settings noDataNoClusterManagerSettings;
+    private Settings noDataClusterManagerSettings;
+    private Settings searchNoDataNoClusterManagerSettings;
+    private Settings noSearchNoClusterManagerSettings;
 
     @Before
     public void createNodePaths() throws IOException {
-        dataMasterSettings = buildEnvSettings(Settings.EMPTY);
-        environment = TestEnvironment.newEnvironment(dataMasterSettings);
-        try (NodeEnvironment nodeEnvironment = new NodeEnvironment(dataMasterSettings, environment)) {
+        dataClusterManagerSettings = buildEnvSettings(Settings.EMPTY);
+        Settings defaultSearchSettings = Settings.builder()
+            .put(dataClusterManagerSettings)
+            .put(NODE_SEARCH_CACHE_SIZE_SETTING.getKey(), new ByteSizeValue(16, ByteSizeUnit.GB))
+            .build();
+
+        searchNoDataNoClusterManagerSettings = onlyRole(dataClusterManagerSettings, DiscoveryNodeRole.SEARCH_ROLE);
+        dataSearchClusterManagerSettings = addRoles(defaultSearchSettings, Set.of(DiscoveryNodeRole.SEARCH_ROLE));
+        noDataClusterManagerSettings = clusterManagerNode(nonDataNode(dataClusterManagerSettings));
+
+        dataSearchNoClusterManagerSettings = nonClusterManagerNode(dataSearchClusterManagerSettings);
+        noSearchNoClusterManagerSettings = nonClusterManagerNode(defaultSearchSettings);
+
+        noDataNoClusterManagerSettings = removeRoles(
+            dataClusterManagerSettings,
+            Set.of(DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)
+        );
+
+        environment = TestEnvironment.newEnvironment(dataClusterManagerSettings);
+        try (NodeEnvironment nodeEnvironment = new NodeEnvironment(dataClusterManagerSettings, environment)) {
             nodePaths = nodeEnvironment.nodeDataPaths();
             final String nodeId = randomAlphaOfLength(10);
             try (
@@ -95,36 +120,29 @@ public void createNodePaths() throws IOException {
                     nodeId,
                     xContentRegistry(),
                     BigArrays.NON_RECYCLING_INSTANCE,
-                    new ClusterSettings(dataMasterSettings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                    new ClusterSettings(dataClusterManagerSettings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
                     () -> 0L
                 ).createWriter()
             ) {
                 writer.writeFullStateAndCommit(1L, ClusterState.EMPTY_STATE);
             }
         }
-        dataNoMasterSettings = nonMasterNode(dataMasterSettings);
-        noDataNoMasterSettings = removeRoles(
-            dataMasterSettings,
-            Collections.unmodifiableSet(new HashSet<>(Arrays.asList(DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)))
-        );
-
-        noDataMasterSettings = masterNode(nonDataNode(dataMasterSettings));
     }
 
     public void testEarlyExitNoCleanup() throws Exception {
-        createIndexDataFiles(dataMasterSettings, randomInt(10), randomBoolean());
+        createIndexDataFiles(dataClusterManagerSettings, randomInt(10), randomBoolean());
 
-        verifyNoQuestions(dataMasterSettings, containsString(NO_CLEANUP));
-        verifyNoQuestions(dataNoMasterSettings, containsString(NO_CLEANUP));
+        verifyNoQuestions(dataSearchClusterManagerSettings, containsString(NO_CLEANUP));
+        verifyNoQuestions(dataSearchNoClusterManagerSettings, containsString(NO_CLEANUP));
     }
 
     public void testNothingToCleanup() throws Exception {
-        verifyNoQuestions(noDataNoMasterSettings, containsString(NO_DATA_TO_CLEAN_UP_FOUND));
-        verifyNoQuestions(noDataMasterSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noDataNoClusterManagerSettings, containsString(NO_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noDataClusterManagerSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
 
-        Environment environment = TestEnvironment.newEnvironment(noDataMasterSettings);
+        Environment environment = TestEnvironment.newEnvironment(noDataClusterManagerSettings);
         if (randomBoolean()) {
-            try (NodeEnvironment env = new NodeEnvironment(noDataMasterSettings, environment)) {
+            try (NodeEnvironment env = new NodeEnvironment(noDataClusterManagerSettings, environment)) {
                 try (
                     PersistedClusterStateService.Writer writer = OpenSearchNodeCommand.createPersistedClusterStateService(
                         Settings.EMPTY,
@@ -136,31 +154,37 @@ public void testNothingToCleanup() throws Exception {
             }
         }
 
-        verifyNoQuestions(noDataNoMasterSettings, containsString(NO_DATA_TO_CLEAN_UP_FOUND));
-        verifyNoQuestions(noDataMasterSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noDataNoClusterManagerSettings, containsString(NO_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noDataClusterManagerSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noSearchNoClusterManagerSettings, containsString(NO_FILE_CACHE_DATA_TO_CLEAN_UP_FOUND));
 
-        createIndexDataFiles(dataMasterSettings, 0, randomBoolean());
+        createIndexDataFiles(dataClusterManagerSettings, 0, randomBoolean());
 
-        verifyNoQuestions(noDataMasterSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
+        verifyNoQuestions(noDataClusterManagerSettings, containsString(NO_SHARD_DATA_TO_CLEAN_UP_FOUND));
 
     }
 
     public void testLocked() throws IOException {
-        try (NodeEnvironment env = new NodeEnvironment(dataMasterSettings, TestEnvironment.newEnvironment(dataMasterSettings))) {
+        try (
+            NodeEnvironment env = new NodeEnvironment(
+                dataClusterManagerSettings,
+                TestEnvironment.newEnvironment(dataClusterManagerSettings)
+            )
+        ) {
             assertThat(
-                expectThrows(OpenSearchException.class, () -> verifyNoQuestions(noDataNoMasterSettings, null)).getMessage(),
+                expectThrows(OpenSearchException.class, () -> verifyNoQuestions(noDataNoClusterManagerSettings, null)).getMessage(),
                 containsString(NodeRepurposeCommand.FAILED_TO_OBTAIN_NODE_LOCK_MSG)
             );
         }
     }
 
-    public void testCleanupAll() throws Exception {
+    public void testCleanupDataClusterManager() throws Exception {
         int shardCount = randomIntBetween(1, 10);
         boolean verbose = randomBoolean();
         boolean hasClusterState = randomBoolean();
-        createIndexDataFiles(dataMasterSettings, shardCount, hasClusterState);
+        createIndexDataFiles(dataClusterManagerSettings, shardCount, hasClusterState);
 
-        String messageText = NodeRepurposeCommand.noMasterMessage(1, environment.dataFiles().length * shardCount, 0);
+        String messageText = NodeRepurposeCommand.noClusterManagerMessage(1, environment.dataFiles().length * shardCount, 0);
 
         Matcher<String> outputMatcher = allOf(
             containsString(messageText),
@@ -168,22 +192,22 @@ public void testCleanupAll() throws Exception {
             conditionalNot(containsString("no name for uuid: testUUID"), verbose == false || hasClusterState)
         );
 
-        verifyUnchangedOnAbort(noDataNoMasterSettings, outputMatcher, verbose);
+        verifyUnchangedOnAbort(noDataNoClusterManagerSettings, outputMatcher, verbose);
 
         // verify test setup
-        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noDataNoMasterSettings, environment).close());
+        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noDataNoClusterManagerSettings, environment).close());
 
-        verifySuccess(noDataNoMasterSettings, outputMatcher, verbose);
+        verifySuccess(noDataNoClusterManagerSettings, outputMatcher, verbose);
 
         // verify cleaned.
-        new NodeEnvironment(noDataNoMasterSettings, environment).close();
+        new NodeEnvironment(noDataNoClusterManagerSettings, environment).close();
     }
 
     public void testCleanupShardData() throws Exception {
         int shardCount = randomIntBetween(1, 10);
         boolean verbose = randomBoolean();
         boolean hasClusterState = randomBoolean();
-        createIndexDataFiles(dataMasterSettings, shardCount, hasClusterState);
+        createIndexDataFiles(dataClusterManagerSettings, shardCount, hasClusterState);
 
         Matcher<String> matcher = allOf(
             containsString(NodeRepurposeCommand.shardMessage(environment.dataFiles().length * shardCount, 1)),
@@ -192,15 +216,93 @@ public void testCleanupShardData() throws Exception {
             conditionalNot(containsString("no name for uuid: testUUID"), verbose == false || hasClusterState)
         );
 
-        verifyUnchangedOnAbort(noDataMasterSettings, matcher, verbose);
+        verifyUnchangedOnAbort(noDataClusterManagerSettings, matcher, verbose);
 
         // verify test setup
-        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noDataMasterSettings, environment).close());
+        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noDataClusterManagerSettings, environment).close());
 
-        verifySuccess(noDataMasterSettings, matcher, verbose);
+        verifySuccess(noDataClusterManagerSettings, matcher, verbose);
 
         // verify clean.
-        new NodeEnvironment(noDataMasterSettings, environment).close();
+        new NodeEnvironment(noDataClusterManagerSettings, environment).close();
+    }
+
+    public void testCleanupSearchNode() throws Exception {
+        int shardCount = randomIntBetween(1, 10);
+        boolean verbose = randomBoolean();
+        boolean hasClusterState = randomBoolean();
+        createIndexDataFiles(searchNoDataNoClusterManagerSettings, shardCount, hasClusterState, true);
+
+        Matcher<String> matcher = allOf(
+            containsString(NodeRepurposeCommand.shardMessage(shardCount, 1)),
+            conditionalNot(containsString("testUUID"), verbose == false),
+            conditionalNot(containsString("testIndex"), verbose == false || hasClusterState == false),
+            conditionalNot(containsString("no name for uuid: testUUID"), verbose == false || hasClusterState)
+        );
+
+        verifyUnchangedOnAbort(dataClusterManagerSettings, matcher, verbose);
+
+        // verify test setup
+        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(dataClusterManagerSettings, environment).close());
+
+        verifySuccess(dataClusterManagerSettings, matcher, verbose);
+
+        // verify clean.
+        new NodeEnvironment(dataClusterManagerSettings, environment).close();
+    }
+
+    public void testCleanupSearchClusterManager() throws Exception {
+        int shardCount = randomIntBetween(1, 10);
+        boolean verbose = randomBoolean();
+        boolean hasClusterState = randomBoolean();
+        createIndexDataFiles(dataSearchClusterManagerSettings, shardCount, hasClusterState, true);
+
+        String messageText = NodeRepurposeCommand.noClusterManagerMessage(1, shardCount, 0);
+
+        Matcher<String> matcher = allOf(
+            containsString(messageText),
+            conditionalNot(containsString("testUUID"), verbose == false),
+            conditionalNot(containsString("testIndex"), verbose == false || hasClusterState == false),
+            conditionalNot(containsString("no name for uuid: testUUID"), verbose == false || hasClusterState)
+        );
+
+        verifyUnchangedOnAbort(noSearchNoClusterManagerSettings, matcher, verbose);
+
+        // verify test setup
+        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noSearchNoClusterManagerSettings, environment).close());
+
+        verifySuccess(noSearchNoClusterManagerSettings, matcher, verbose);
+
+        // verify clean.
+        new NodeEnvironment(noSearchNoClusterManagerSettings, environment).close();
+    }
+
+    public void testCleanupAll() throws Exception {
+        int shardCount = randomIntBetween(1, 10);
+        boolean verbose = randomBoolean();
+        boolean hasClusterState = randomBoolean();
+        createIndexDataFiles(dataSearchClusterManagerSettings, shardCount, hasClusterState, false);
+        createIndexDataFiles(dataSearchClusterManagerSettings, shardCount, hasClusterState, true);
+
+        // environment.dataFiles().length * shardCount will account for the local shard files
+        // + shardCount will account for the additional file cache shard files.
+        String messageText = NodeRepurposeCommand.noClusterManagerMessage(1, (environment.dataFiles().length * shardCount) + shardCount, 0);
+
+        Matcher<String> outputMatcher = allOf(
+            containsString(messageText),
+            conditionalNot(containsString("testIndex"), verbose == false || hasClusterState == false),
+            conditionalNot(containsString("no name for uuid: testUUID"), verbose == false || hasClusterState)
+        );
+
+        verifyUnchangedOnAbort(noDataNoClusterManagerSettings, outputMatcher, verbose);
+
+        // verify test setup
+        expectThrows(IllegalStateException.class, () -> new NodeEnvironment(noDataNoClusterManagerSettings, environment).close());
+
+        verifySuccess(noDataNoClusterManagerSettings, outputMatcher, verbose);
+
+        // verify cleaned.
+        new NodeEnvironment(noDataNoClusterManagerSettings, environment).close();
     }
 
     static void verifySuccess(Settings settings, Matcher<String> outputMatcher, boolean verbose) throws Exception {
@@ -251,6 +353,10 @@ private static void executeRepurposeCommand(MockTerminal terminal, Settings sett
     }
 
     private void createIndexDataFiles(Settings settings, int shardCount, boolean writeClusterState) throws IOException {
+        createIndexDataFiles(settings, shardCount, writeClusterState, false);
+    }
+
+    private void createIndexDataFiles(Settings settings, int shardCount, boolean writeClusterState, boolean cacheMode) throws IOException {
         int shardDataDirNumber = randomInt(10);
         Environment environment = TestEnvironment.newEnvironment(settings);
         try (NodeEnvironment env = new NodeEnvironment(settings, environment)) {
@@ -282,12 +388,23 @@ private void createIndexDataFiles(Settings settings, int shardCount, boolean wri
                     );
                 }
             }
-            for (Path path : env.indexPaths(INDEX)) {
+
+            if (cacheMode) {
+                Path cachePath = env.fileCacheNodePath().fileCachePath;
+                cachePath = cachePath.resolve(INDEX.getUUID());
                 for (int i = 0; i < shardCount; ++i) {
-                    Files.createDirectories(path.resolve(Integer.toString(shardDataDirNumber)));
+                    Files.createDirectories(cachePath.resolve(Integer.toString(shardDataDirNumber)));
                     shardDataDirNumber += randomIntBetween(1, 10);
                 }
+            } else {
+                for (Path path : env.indexPaths(INDEX)) {
+                    for (int i = 0; i < shardCount; ++i) {
+                        Files.createDirectories(path.resolve(Integer.toString(shardDataDirNumber)));
+                        shardDataDirNumber += randomIntBetween(1, 10);
+                    }
+                }
             }
+
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/extensions/DiscoveryExtensionNodeTests.java b/server/src/test/java/org/opensearch/extensions/DiscoveryExtensionNodeTests.java
new file mode 100644
index 0000000000000..cb7eb7b4f5910
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/DiscoveryExtensionNodeTests.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Collections;
+import java.util.HashMap;
+
+public class DiscoveryExtensionNodeTests extends OpenSearchTestCase {
+
+    public void testExtensionNode() throws UnknownHostException {
+        DiscoveryExtensionNode extensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "extensionUniqueId1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<String, String>(),
+            Version.CURRENT,
+            // minimum compatible version
+            Version.CURRENT,
+            Collections.emptyList()
+        );
+        assertTrue(Version.CURRENT.onOrAfter(extensionNode.getMinimumCompatibleVersion()));
+    }
+
+    public void testIncompatibleExtensionNode() throws UnknownHostException {
+        expectThrows(
+            OpenSearchException.class,
+            () -> new DiscoveryExtensionNode(
+                "firstExtension",
+                "extensionUniqueId1",
+                new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+                new HashMap<String, String>(),
+                Version.fromString("3.0.0"),
+                // minimum compatible version
+                Version.fromString("3.99.0"),
+                Collections.emptyList()
+            )
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/ExtensionResponseTests.java b/server/src/test/java/org/opensearch/extensions/ExtensionResponseTests.java
new file mode 100644
index 0000000000000..84e13a1ddf5a7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/ExtensionResponseTests.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ExtensionResponseTests extends OpenSearchTestCase {
+
+    public void testAcknowledgedResponse() throws Exception {
+        boolean response = true;
+        AcknowledgedResponse booleanResponse = new AcknowledgedResponse(response);
+
+        assertEquals(response, booleanResponse.getStatus());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            booleanResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                booleanResponse = new AcknowledgedResponse(in);
+
+                assertEquals(response, booleanResponse.getStatus());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java b/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java
new file mode 100644
index 0000000000000..41b0d8f7a45e7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java
@@ -0,0 +1,1036 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions;
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.ClusterSettingsResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsModule;
+import org.opensearch.common.settings.WriteableSetting;
+import org.opensearch.common.settings.WriteableSetting.SettingType;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.discovery.InitializeExtensionRequest;
+import org.opensearch.env.Environment;
+import org.opensearch.env.EnvironmentSettingsResponse;
+import org.opensearch.extensions.ExtensionsSettings.Extension;
+import org.opensearch.extensions.proto.ExtensionRequestProto;
+import org.opensearch.extensions.rest.RegisterRestActionsRequest;
+import org.opensearch.extensions.settings.RegisterCustomSettingsRequest;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.plugins.ExtensionAwarePlugin;
+import org.opensearch.rest.RestController;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.FeatureFlagSetter;
+import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.client.NoOpNodeClient;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transport;
+import org.opensearch.transport.TransportService;
+import org.opensearch.transport.nio.MockNioTransport;
+import org.opensearch.usage.UsageService;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class ExtensionsManagerTests extends OpenSearchTestCase {
+    private TransportService transportService;
+    private ActionModule actionModule;
+    private DynamicActionRegistry dynamicActionRegistry;
+    private RestController restController;
+    private SettingsModule settingsModule;
+    private ClusterService clusterService;
+    private ExtensionAwarePlugin extAwarePlugin;
+    private Setting customSetting = Setting.simpleString("custom_extension_setting", "none", Property.ExtensionScope);
+    private NodeClient client;
+    private MockNioTransport transport;
+    private final ThreadPool threadPool = new TestThreadPool(ExtensionsManagerTests.class.getSimpleName());
+    private final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+        .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+        .build();
+
+    private DiscoveryExtensionNode extensionNode;
+
+    @Before
+    public void setup() throws Exception {
+        FeatureFlagSetter.set(FeatureFlags.EXTENSIONS);
+        Settings settings = Settings.builder().put("cluster.name", "test").build();
+        transport = new MockNioTransport(
+            settings,
+            Version.CURRENT,
+            threadPool,
+            new NetworkService(Collections.emptyList()),
+            PageCacheRecycler.NON_RECYCLING_INSTANCE,
+            new NamedWriteableRegistry(Collections.emptyList()),
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
+        );
+        transportService = new MockTransportService(
+            settings,
+            transport,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            (boundAddress) -> new DiscoveryNode(
+                "test_node",
+                "test_node",
+                boundAddress.publishAddress(),
+                emptyMap(),
+                emptySet(),
+                Version.CURRENT
+            ),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        actionModule = mock(ActionModule.class);
+        extAwarePlugin = new ExtensionAwarePlugin() {
+
+            @Override
+            public List<Setting<?>> getExtensionSettings() {
+                List<Setting<?>> settings = new ArrayList<Setting<?>>();
+                settings.add(customSetting);
+                return settings;
+            }
+        };
+        dynamicActionRegistry = mock(DynamicActionRegistry.class);
+        restController = new RestController(
+            emptySet(),
+            null,
+            new NodeClient(Settings.EMPTY, threadPool),
+            new NoneCircuitBreakerService(),
+            new UsageService(),
+            new IdentityService(Settings.EMPTY, List.of())
+        );
+        when(actionModule.getDynamicActionRegistry()).thenReturn(mock(DynamicActionRegistry.class));
+        when(actionModule.getRestController()).thenReturn(restController);
+        settingsModule = new SettingsModule(Settings.EMPTY, emptyList(), emptyList(), emptySet());
+        clusterService = createClusterService(threadPool);
+
+        extensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<String, String>(),
+            Version.CURRENT,
+            Version.CURRENT,
+            Collections.emptyList()
+        );
+        client = new NoOpNodeClient(this.getTestName());
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        transportService.close();
+        client.close();
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+    }
+
+    public void testLoadExtensions() throws Exception {
+
+        Set<Setting<?>> additionalSettings = extAwarePlugin.getExtensionSettings().stream().collect(Collectors.toSet());
+        ExtensionScopedSettings extensionScopedSettings = new ExtensionScopedSettings(additionalSettings);
+        ExtensionsManager extensionsManager = new ExtensionsManager(additionalSettings);
+        ExtensionDependency dependentExtension = new ExtensionDependency("uniqueid0", Version.fromString("2.0.0"));
+
+        Extension firstExtension = new Extension(
+            "firstExtension",
+            "uniqueid1",
+            "127.0.0.1",
+            "9300",
+            "0.0.7",
+            Version.CURRENT.toString(),
+            "2.0.0",
+            Collections.emptyList(),
+            extensionScopedSettings
+        );
+        Extension secondExtension = new Extension(
+            "secondExtension",
+            "uniqueid2",
+            "127.0.0.1",
+            "9301",
+            "0.0.7",
+            Version.CURRENT.toString(),
+            "2.0.0",
+            List.of(dependentExtension),
+            extensionScopedSettings
+        );
+        extensionsManager.loadExtension(firstExtension);
+        extensionsManager.loadExtension(secondExtension);
+
+        List<DiscoveryExtensionNode> expectedExtensions = new ArrayList<DiscoveryExtensionNode>();
+
+        String expectedUniqueId = "uniqueid0";
+        Version expectedVersion = Version.fromString("2.0.0");
+        ExtensionDependency expectedDependency = new ExtensionDependency(expectedUniqueId, expectedVersion);
+
+        expectedExtensions.add(
+            new DiscoveryExtensionNode(
+                "firstExtension",
+                "uniqueid1",
+                new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300),
+                new HashMap<String, String>(),
+                Version.CURRENT,
+                Version.fromString("2.0.0"),
+                Collections.emptyList()
+            )
+        );
+
+        expectedExtensions.add(
+            new DiscoveryExtensionNode(
+                "secondExtension",
+                "uniqueid2",
+                new TransportAddress(InetAddress.getByName("127.0.0.1"), 9301),
+                new HashMap<String, String>(),
+                Version.CURRENT,
+                Version.fromString("2.0.0"),
+                List.of(expectedDependency)
+            )
+        );
+        assertEquals(expectedExtensions.size(), extensionsManager.getExtensionIdMap().values().size());
+        assertEquals(List.of(expectedDependency), expectedExtensions.get(1).getDependencies());
+        for (DiscoveryExtensionNode extension : expectedExtensions) {
+            DiscoveryExtensionNode initializedExtension = extensionsManager.getExtensionIdMap().get(extension.getId());
+            assertEquals(extension.getName(), initializedExtension.getName());
+            assertEquals(extension.getId(), initializedExtension.getId());
+            assertEquals(extension.getAddress(), initializedExtension.getAddress());
+            assertEquals(extension.getAttributes(), initializedExtension.getAttributes());
+            assertEquals(extension.getVersion(), initializedExtension.getVersion());
+            assertEquals(extension.getMinimumCompatibleVersion(), initializedExtension.getMinimumCompatibleVersion());
+            assertEquals(extension.getDependencies(), initializedExtension.getDependencies());
+            assertTrue(extensionsManager.lookupExtensionSettingsById(extension.getId()).isPresent());
+        }
+    }
+
+    public void testNonUniqueLoadedExtensions() throws Exception {
+
+        Extension firstExtension = new Extension(
+            "firstExtension",
+            "uniqueid1",
+            "127.0.0.0",
+            "9300",
+            "0.0.7",
+            Version.CURRENT.toString(),
+            "2.0.0",
+            Collections.emptyList(),
+            null
+        );
+        Extension secondExtension = new Extension(
+            "secondExtension",
+            "uniqueid1",
+            "127.0.0.0",
+            "9300",
+            "0.0.7",
+            Version.CURRENT.toString(),
+            "2.0.0",
+            null,
+            null
+        );
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        extensionsManager.loadExtension(firstExtension);
+        IOException exception = expectThrows(IOException.class, () -> extensionsManager.loadExtension(secondExtension));
+        assertEquals(
+            "Duplicate uniqueId [uniqueid1]. Did not load extension: Extension [name=secondExtension, uniqueId=uniqueid1, hostAddress=127.0.0.0, port=9300, version=0.0.7, opensearchVersion="
+                + Version.CURRENT
+                + ", minimumCompatibleVersion=2.0.0]",
+            exception.getMessage()
+        );
+
+        List<DiscoveryExtensionNode> expectedExtensions = new ArrayList<DiscoveryExtensionNode>();
+
+        expectedExtensions.add(
+            new DiscoveryExtensionNode(
+                "firstExtension",
+                "uniqueid1",
+                new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+                new HashMap<String, String>(),
+                Version.CURRENT,
+                Version.fromString("2.0.0."),
+                Collections.emptyList()
+            )
+        );
+        assertEquals(expectedExtensions.size(), extensionsManager.getExtensionIdMap().values().size());
+        for (DiscoveryExtensionNode extension : expectedExtensions) {
+            DiscoveryExtensionNode initializedExtension = extensionsManager.getExtensionIdMap().get(extension.getId());
+            assertEquals(extension.getName(), initializedExtension.getName());
+            assertEquals(extension.getId(), initializedExtension.getId());
+            assertEquals(extension.getAddress(), initializedExtension.getAddress());
+            assertEquals(extension.getAttributes(), initializedExtension.getAttributes());
+            assertEquals(extension.getVersion(), initializedExtension.getVersion());
+            assertEquals(extension.getMinimumCompatibleVersion(), initializedExtension.getMinimumCompatibleVersion());
+            assertEquals(extension.getDependencies(), initializedExtension.getDependencies());
+        }
+        assertTrue(expectedExtensions.containsAll(emptyList()));
+        assertTrue(expectedExtensions.containsAll(emptyList()));
+    }
+
+    public void testMissingRequiredFieldsWhileLoadingExtension() throws Exception {
+
+        Extension firstExtension = new Extension("firstExtension", "uniqueid1", "127.0.0.0", "9300", "0.0.7", "3.0.0", "", null, null);
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+
+        IOException exception = expectThrows(IOException.class, () -> extensionsManager.loadExtension(firstExtension));
+        assertEquals("Required field [minimum opensearch version] is missing in the request", exception.getMessage());
+
+        assertEquals(0, extensionsManager.getExtensionIdMap().values().size());
+    }
+
+    public void testDiscoveryExtension() throws Exception {
+        String expectedId = "test id";
+        Version expectedVersion = Version.fromString("2.0.0");
+        ExtensionDependency expectedDependency = new ExtensionDependency(expectedId, expectedVersion);
+
+        DiscoveryExtensionNode discoveryExtensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<String, String>(),
+            Version.CURRENT,
+            Version.CURRENT,
+            List.of(expectedDependency)
+        );
+
+        assertEquals(List.of(expectedDependency), discoveryExtensionNode.getDependencies());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            discoveryExtensionNode.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                discoveryExtensionNode = new DiscoveryExtensionNode(in);
+
+                assertEquals(List.of(expectedDependency), discoveryExtensionNode.getDependencies());
+            }
+        }
+    }
+
+    public void testExtensionDependency() throws Exception {
+        String expectedUniqueId = "Test uniqueId";
+        Version expectedVersion = Version.CURRENT;
+
+        ExtensionDependency dependency = new ExtensionDependency(expectedUniqueId, expectedVersion);
+
+        assertEquals(expectedUniqueId, dependency.getUniqueId());
+        assertEquals(expectedVersion, dependency.getVersion());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            dependency.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                dependency = new ExtensionDependency(in);
+                assertEquals(expectedUniqueId, dependency.getUniqueId());
+                assertEquals(expectedVersion, dependency.getVersion());
+            }
+        }
+    }
+
+    public void testInitialize() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+
+        initialize(extensionsManager);
+
+        try (MockLogAppender mockLogAppender = MockLogAppender.createForLoggers(LogManager.getLogger(ExtensionsManager.class))) {
+
+            mockLogAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "Node Not Connected Exception 1",
+                    "org.opensearch.extensions.ExtensionsManager",
+                    Level.ERROR,
+                    "[secondExtension][127.0.0.1:9301] Node not connected"
+                )
+            );
+
+            mockLogAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "Node Not Connected Exception 2",
+                    "org.opensearch.extensions.ExtensionsManager",
+                    Level.ERROR,
+                    "[firstExtension][127.0.0.0:9300] Node not connected"
+                )
+            );
+
+            mockLogAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "No Response From Extension",
+                    "org.opensearch.extensions.ExtensionsManager",
+                    Level.INFO,
+                    "No response from extension to request."
+                )
+            );
+
+            // Test needs to be changed to mock the connection between the local node and an extension.
+            // Link to issue: https://github.com/opensearch-project/OpenSearch/issues/4045
+            // mockLogAppender.assertAllExpectationsMatched();
+        }
+    }
+
+    public void testInitializeExtension() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+
+        TransportService mockTransportService = spy(
+            new TransportService(
+                Settings.EMPTY,
+                mock(Transport.class),
+                threadPool,
+                TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+                x -> null,
+                null,
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
+            )
+        );
+
+        doNothing().when(mockTransportService).connectToExtensionNode(any(DiscoveryExtensionNode.class));
+
+        doNothing().when(mockTransportService)
+            .sendRequest(any(DiscoveryExtensionNode.class), anyString(), any(InitializeExtensionRequest.class), any());
+
+        extensionsManager.initializeServicesAndRestHandler(
+            actionModule,
+            settingsModule,
+            mockTransportService,
+            clusterService,
+            settings,
+            client
+        );
+
+        Extension firstExtension = new Extension(
+            "firstExtension",
+            "uniqueid1",
+            "127.0.0.0",
+            "9301",
+            "0.0.7",
+            "2.0.0",
+            "2.0.0",
+            List.of(),
+            null
+        );
+
+        extensionsManager.initializeExtension(firstExtension);
+
+        Extension secondExtension = new Extension(
+            "secondExtension",
+            "uniqueid2",
+            "127.0.0.0",
+            "9301",
+            "0.0.7",
+            "2.0.0",
+            "2.0.0",
+            List.of(),
+            null
+        );
+
+        extensionsManager.initializeExtension(secondExtension);
+
+        ThreadPool.terminate(threadPool, 3, TimeUnit.SECONDS);
+
+        verify(mockTransportService, times(2)).connectToExtensionNode(any(DiscoveryExtensionNode.class));
+
+        verify(mockTransportService, times(2)).sendRequest(
+            any(DiscoveryExtensionNode.class),
+            anyString(),
+            any(InitializeExtensionRequest.class),
+            any()
+        );
+    }
+
+    public void testHandleRegisterRestActionsRequest() throws Exception {
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        String uniqueIdStr = "uniqueid1";
+
+        extensionsManager.loadExtension(
+            new Extension("firstExtension", uniqueIdStr, "127.0.0.0", "9300", "0.0.7", "2.8.0", "2.8.0", List.of(), null)
+        );
+
+        List<String> actionsList = List.of("GET /foo foo", "PUT /bar bar", "POST /baz baz");
+        List<String> deprecatedActionsList = List.of("GET /deprecated/foo foo_deprecated", "It's deprecated!");
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, actionsList, deprecatedActionsList);
+        TransportResponse response = extensionsManager.getRestActionsRequestHandler()
+            .handleRegisterRestActionsRequest(registerActionsRequest, actionModule.getDynamicActionRegistry());
+        assertEquals(AcknowledgedResponse.class, response.getClass());
+        assertTrue(((AcknowledgedResponse) response).getStatus());
+    }
+
+    public void testHandleRegisterRestActionsRequestRequiresDiscoveryNode() throws Exception {
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest("uniqueId1", List.of(), List.of());
+
+        expectThrows(
+            IllegalStateException.class,
+            () -> extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, actionModule.getDynamicActionRegistry())
+        );
+    }
+
+    public void testHandleRegisterRestActionsRequestMultiple() throws Exception {
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        List<String> actionsList = List.of("GET /foo foo", "PUT /bar bar", "POST /baz baz");
+        List<String> deprecatedActionsList = List.of("GET /deprecated/foo foo_deprecated", "It's deprecated!");
+        for (int i = 0; i < 2; i++) {
+            String uniqueIdStr = "uniqueid-%d" + i;
+
+            Set<Setting<?>> additionalSettings = extAwarePlugin.getExtensionSettings().stream().collect(Collectors.toSet());
+            ExtensionScopedSettings extensionScopedSettings = new ExtensionScopedSettings(additionalSettings);
+            Extension firstExtension = new Extension(
+                "Extension %s" + i,
+                uniqueIdStr,
+                "127.0.0.0",
+                "9300",
+                "0.0.7",
+                "2.8.0",
+                "2.8.0",
+                List.of(),
+                extensionScopedSettings
+            );
+
+            extensionsManager.loadExtension(firstExtension);
+
+            RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(
+                uniqueIdStr,
+                actionsList,
+                deprecatedActionsList
+            );
+            TransportResponse response = extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, actionModule.getDynamicActionRegistry());
+            assertEquals(AcknowledgedResponse.class, response.getClass());
+            assertTrue(((AcknowledgedResponse) response).getStatus());
+        }
+    }
+
+    public void testHandleRegisterSettingsRequest() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        String uniqueIdStr = "uniqueid1";
+        List<Setting<?>> settingsList = List.of(
+            Setting.boolSetting("index.falseSetting", false, Property.IndexScope, Property.Dynamic),
+            Setting.simpleString("fooSetting", "foo", Property.NodeScope, Property.Final)
+        );
+        RegisterCustomSettingsRequest registerCustomSettingsRequest = new RegisterCustomSettingsRequest(uniqueIdStr, settingsList);
+        TransportResponse response = extensionsManager.getCustomSettingsRequestHandler()
+            .handleRegisterCustomSettingsRequest(registerCustomSettingsRequest);
+        assertEquals(AcknowledgedResponse.class, response.getClass());
+        assertTrue(((AcknowledgedResponse) response).getStatus());
+    }
+
+    public void testHandleRegisterRestActionsRequestWithInvalidMethod() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        String uniqueIdStr = "uniqueid1";
+        extensionsManager.loadExtension(
+            new Extension("firstExtension", uniqueIdStr, "127.0.0.0", "9300", "0.0.7", "2.8.0", "2.8.0", List.of(), null)
+        );
+        List<String> actionsList = List.of("FOO /foo", "PUT /bar", "POST /baz");
+        List<String> deprecatedActionsList = List.of("GET /deprecated/foo", "It's deprecated!");
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, actionsList, deprecatedActionsList);
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, actionModule.getDynamicActionRegistry())
+        );
+    }
+
+    public void testHandleRegisterRestActionsRequestWithInvalidDeprecatedMethod() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        String uniqueIdStr = "uniqueid1";
+        extensionsManager.loadExtension(
+            new Extension("firstExtension", uniqueIdStr, "127.0.0.0", "9300", "0.0.7", "2.8.0", "2.8.0", List.of(), null)
+        );
+        List<String> actionsList = List.of("GET /foo", "PUT /bar", "POST /baz");
+        List<String> deprecatedActionsList = List.of("FOO /deprecated/foo", "It's deprecated!");
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, actionsList, deprecatedActionsList);
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, actionModule.getDynamicActionRegistry())
+        );
+    }
+
+    public void testHandleRegisterRestActionsRequestWithInvalidUri() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+        String uniqueIdStr = "uniqueid1";
+        extensionsManager.loadExtension(
+            new Extension("firstExtension", uniqueIdStr, "127.0.0.0", "9300", "0.0.7", "2.8.0", "2.8.0", List.of(), null)
+        );
+        List<String> actionsList = List.of("GET", "PUT /bar", "POST /baz");
+        List<String> deprecatedActionsList = List.of("GET /deprecated/foo", "It's deprecated!");
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, actionsList, deprecatedActionsList);
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, dynamicActionRegistry)
+        );
+    }
+
+    public void testHandleRegisterRestActionsRequestWithInvalidDeprecatedUri() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+        String uniqueIdStr = "uniqueid1";
+        extensionsManager.loadExtension(
+            new Extension("firstExtension", uniqueIdStr, "127.0.0.0", "9300", "0.0.7", "2.8.0", "2.8.0", List.of(), null)
+        );
+        List<String> actionsList = List.of("GET /foo", "PUT /bar", "POST /baz");
+        List<String> deprecatedActionsList = List.of("GET", "It's deprecated!");
+        RegisterRestActionsRequest registerActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, actionsList, deprecatedActionsList);
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionsManager.getRestActionsRequestHandler()
+                .handleRegisterRestActionsRequest(registerActionsRequest, dynamicActionRegistry)
+        );
+    }
+
+    public void testHandleExtensionRequest() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        ExtensionRequest clusterStateRequest = new ExtensionRequest(ExtensionRequestProto.RequestType.REQUEST_EXTENSION_CLUSTER_STATE);
+        assertEquals(ClusterStateResponse.class, extensionsManager.handleExtensionRequest(clusterStateRequest).getClass());
+
+        ExtensionRequest clusterSettingRequest = new ExtensionRequest(ExtensionRequestProto.RequestType.REQUEST_EXTENSION_CLUSTER_SETTINGS);
+        assertEquals(ClusterSettingsResponse.class, extensionsManager.handleExtensionRequest(clusterSettingRequest).getClass());
+
+        ExtensionRequest environmentSettingsRequest = new ExtensionRequest(
+            ExtensionRequestProto.RequestType.REQUEST_EXTENSION_ENVIRONMENT_SETTINGS
+        );
+        assertEquals(EnvironmentSettingsResponse.class, extensionsManager.handleExtensionRequest(environmentSettingsRequest).getClass());
+
+        ExtensionRequest exceptionRequest = new ExtensionRequest(ExtensionRequestProto.RequestType.GET_SETTINGS);
+        Exception exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionsManager.handleExtensionRequest(exceptionRequest)
+        );
+        assertEquals("Handler not present for the provided request", exception.getMessage());
+    }
+
+    public void testExtensionRequest() throws Exception {
+        ExtensionRequestProto.RequestType expectedRequestType = ExtensionRequestProto.RequestType.REQUEST_EXTENSION_DEPENDENCY_INFORMATION;
+
+        // Test ExtensionRequest 2 arg constructor
+        String expectedUniqueId = "test uniqueid";
+        ExtensionRequest extensionRequest = new ExtensionRequest(expectedRequestType, expectedUniqueId);
+        assertEquals(expectedRequestType, extensionRequest.getRequestType());
+        assertEquals(expectedUniqueId, extensionRequest.getUniqueId());
+
+        // Test ExtensionRequest StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            extensionRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                extensionRequest = new ExtensionRequest(in);
+                assertEquals(expectedRequestType, extensionRequest.getRequestType());
+                assertEquals(expectedUniqueId, extensionRequest.getUniqueId());
+            }
+        }
+
+        // Test ExtensionRequest 1 arg constructor
+        extensionRequest = new ExtensionRequest(expectedRequestType);
+        assertEquals(expectedRequestType, extensionRequest.getRequestType());
+        assertTrue(extensionRequest.getUniqueId().isEmpty());
+
+        // Test ExtensionRequest StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            extensionRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                extensionRequest = new ExtensionRequest(in);
+                assertEquals(expectedRequestType, extensionRequest.getRequestType());
+                assertTrue(extensionRequest.getUniqueId().isEmpty());
+            }
+        }
+    }
+
+    public void testExtensionDependencyResponse() throws Exception {
+        String expectedUniqueId = "test uniqueid";
+        List<DiscoveryExtensionNode> expectedExtensionsList = new ArrayList<DiscoveryExtensionNode>();
+        Version expectedVersion = Version.fromString("2.0.0");
+        ExtensionDependency expectedDependency = new ExtensionDependency(expectedUniqueId, expectedVersion);
+
+        expectedExtensionsList.add(
+            new DiscoveryExtensionNode(
+                "firstExtension",
+                "uniqueid1",
+                new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+                new HashMap<String, String>(),
+                Version.CURRENT,
+                Version.CURRENT,
+                List.of(expectedDependency)
+            )
+        );
+
+        // Test ExtensionDependencyResponse arg constructor
+        ExtensionDependencyResponse extensionDependencyResponse = new ExtensionDependencyResponse(expectedExtensionsList);
+        assertEquals(expectedExtensionsList, extensionDependencyResponse.getExtensionDependency());
+
+        // Test ExtensionDependencyResponse StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            extensionDependencyResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                extensionDependencyResponse = new ExtensionDependencyResponse(in);
+                assertEquals(expectedExtensionsList, extensionDependencyResponse.getExtensionDependency());
+            }
+        }
+    }
+
+    public void testEnvironmentSettingsResponse() throws Exception {
+
+        // Test EnvironmentSettingsResponse arg constructor
+        EnvironmentSettingsResponse environmentSettingsResponse = new EnvironmentSettingsResponse(settings);
+        assertEquals(settings, environmentSettingsResponse.getEnvironmentSettings());
+
+        // Test EnvironmentSettingsResponse StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            environmentSettingsResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                environmentSettingsResponse = new EnvironmentSettingsResponse(in);
+                assertEquals(settings, environmentSettingsResponse.getEnvironmentSettings());
+            }
+        }
+
+    }
+
+    public void testEnvironmentSettingsRegisteredValue() throws Exception {
+        // Create setting with value false
+        Setting<Boolean> boolSetting = Setting.boolSetting("boolSetting", false, Property.Dynamic);
+
+        // Create Settings with registered bool setting with value true
+        Settings environmentSettings = Settings.builder().put("boolSetting", "true").build();
+
+        EnvironmentSettingsResponse environmentSettingsResponse = new EnvironmentSettingsResponse(environmentSettings);
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            environmentSettingsResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+
+                environmentSettingsResponse = new EnvironmentSettingsResponse(in);
+                assertEquals(environmentSettings, environmentSettingsResponse.getEnvironmentSettings());
+
+                // bool setting is registered in Settings object, thus the expected return value is the registered setting value
+                assertEquals(true, boolSetting.get(environmentSettingsResponse.getEnvironmentSettings()));
+            }
+        }
+    }
+
+    public void testEnvironmentSettingsDefaultValue() throws Exception {
+        // Create setting with value false
+        Setting<Boolean> boolSetting = Setting.boolSetting("boolSetting", false, Property.Dynamic);
+
+        // Create settings object without registered bool setting
+        Settings environmentSettings = Settings.builder().put("testSetting", "true").build();
+
+        EnvironmentSettingsResponse environmentSettingsResponse = new EnvironmentSettingsResponse(environmentSettings);
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            environmentSettingsResponse.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+
+                environmentSettingsResponse = new EnvironmentSettingsResponse(in);
+                assertEquals(environmentSettings, environmentSettingsResponse.getEnvironmentSettings());
+                // bool setting is not registered in Settings object, thus the expected return value is the default setting value
+                assertEquals(false, boolSetting.get(environmentSettingsResponse.getEnvironmentSettings()));
+            }
+        }
+    }
+
+    public void testAddSettingsUpdateConsumerRequest() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        List<Setting<?>> componentSettings = List.of(
+            Setting.boolSetting("falseSetting", false, Property.IndexScope, Property.NodeScope),
+            Setting.simpleString("fooSetting", "foo", Property.Dynamic)
+        );
+
+        // Test AddSettingsUpdateConsumerRequest arg constructor
+        AddSettingsUpdateConsumerRequest addSettingsUpdateConsumerRequest = new AddSettingsUpdateConsumerRequest(
+            extensionNode,
+            componentSettings
+        );
+        assertEquals(extensionNode, addSettingsUpdateConsumerRequest.getExtensionNode());
+        assertEquals(componentSettings.size(), addSettingsUpdateConsumerRequest.getComponentSettings().size());
+
+        List<Setting<?>> requestComponentSettings = new ArrayList<>();
+        for (WriteableSetting writeableSetting : addSettingsUpdateConsumerRequest.getComponentSettings()) {
+            requestComponentSettings.add(writeableSetting.getSetting());
+        }
+        assertTrue(requestComponentSettings.containsAll(componentSettings));
+        assertTrue(componentSettings.containsAll(requestComponentSettings));
+
+        // Test AddSettingsUpdateConsumerRequest StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            addSettingsUpdateConsumerRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                addSettingsUpdateConsumerRequest = new AddSettingsUpdateConsumerRequest(in);
+                assertEquals(extensionNode, addSettingsUpdateConsumerRequest.getExtensionNode());
+                assertEquals(componentSettings.size(), addSettingsUpdateConsumerRequest.getComponentSettings().size());
+
+                requestComponentSettings = new ArrayList<>();
+                for (WriteableSetting writeableSetting : addSettingsUpdateConsumerRequest.getComponentSettings()) {
+                    requestComponentSettings.add(writeableSetting.getSetting());
+                }
+                assertTrue(requestComponentSettings.containsAll(componentSettings));
+                assertTrue(componentSettings.containsAll(requestComponentSettings));
+            }
+        }
+
+    }
+
+    public void testHandleAddSettingsUpdateConsumerRequest() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        List<Setting<?>> componentSettings = List.of(
+            Setting.boolSetting("falseSetting", false, Property.Dynamic),
+            Setting.boolSetting("trueSetting", true, Property.Dynamic)
+        );
+
+        AddSettingsUpdateConsumerRequest addSettingsUpdateConsumerRequest = new AddSettingsUpdateConsumerRequest(
+            extensionNode,
+            componentSettings
+        );
+        TransportResponse response = extensionsManager.getAddSettingsUpdateConsumerRequestHandler()
+            .handleAddSettingsUpdateConsumerRequest(addSettingsUpdateConsumerRequest);
+        assertEquals(AcknowledgedResponse.class, response.getClass());
+        // Should fail as component settings are not registered within cluster settings
+        assertEquals(false, ((AcknowledgedResponse) response).getStatus());
+    }
+
+    public void testUpdateSettingsRequest() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        initialize(extensionsManager);
+
+        Setting<?> componentSetting = Setting.boolSetting("falseSetting", false, Property.Dynamic);
+        SettingType settingType = SettingType.Boolean;
+        boolean data = true;
+
+        // Test UpdateSettingRequest arg constructor
+        UpdateSettingsRequest updateSettingsRequest = new UpdateSettingsRequest(settingType, componentSetting, data);
+        assertEquals(componentSetting, updateSettingsRequest.getComponentSetting());
+        assertEquals(settingType, updateSettingsRequest.getSettingType());
+        assertEquals(data, updateSettingsRequest.getData());
+
+        // Test UpdateSettingRequest StreamInput constructor
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            updateSettingsRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                updateSettingsRequest = new UpdateSettingsRequest(in);
+                assertEquals(componentSetting, updateSettingsRequest.getComponentSetting());
+                assertEquals(settingType, updateSettingsRequest.getSettingType());
+                assertEquals(data, updateSettingsRequest.getData());
+            }
+        }
+
+    }
+
+    public void testRegisterHandler() throws Exception {
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+
+        TransportService mockTransportService = spy(
+            new TransportService(
+                Settings.EMPTY,
+                mock(Transport.class),
+                null,
+                TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+                x -> null,
+                null,
+                Collections.emptySet(),
+                NoopTracer.INSTANCE
+            )
+        );
+        extensionsManager.initializeServicesAndRestHandler(
+            actionModule,
+            settingsModule,
+            mockTransportService,
+            clusterService,
+            settings,
+            client
+        );
+        verify(mockTransportService, times(9)).registerRequestHandler(anyString(), anyString(), anyBoolean(), anyBoolean(), any(), any());
+
+    }
+
+    public void testIncompatibleExtensionRegistration() throws IOException {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        Extension firstExtension = new Extension(
+            "firstExtension",
+            "uniqueid1",
+            "127.0.0.0",
+            "9300",
+            "0.0.7",
+            "2.8.0",
+            "3.99.0",
+            List.of(),
+            null
+        );
+        expectThrows(OpenSearchException.class, () -> extensionsManager.loadExtension(firstExtension));
+        assertEquals(0, extensionsManager.getExtensionIdMap().values().size());
+    }
+
+    public void testAdditionalExtensionSettingsForExtensionWithCustomSettingSet() throws Exception {
+        Setting customSetting = Setting.simpleString("custom_extension_setting", "custom_setting", Property.ExtensionScope);
+        ExtensionAwarePlugin extAwarePlugin = new ExtensionAwarePlugin() {
+
+            @Override
+            public List<Setting<?>> getExtensionSettings() {
+                List<Setting<?>> settings = new ArrayList<Setting<?>>();
+                settings.add(customSetting);
+                return settings;
+            }
+        };
+        Set<Setting<?>> additionalSettings = extAwarePlugin.getExtensionSettings().stream().collect(Collectors.toSet());
+        ExtensionScopedSettings extensionScopedSettings = new ExtensionScopedSettings(additionalSettings);
+        Extension firstExtension = new Extension(
+            "firstExtension",
+            "uniqueid1",
+            "127.0.0.0",
+            "9300",
+            "0.0.7",
+            Version.CURRENT.toString(),
+            "2.0.0",
+            List.of(),
+            extensionScopedSettings
+        );
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(additionalSettings);
+        extensionsManager.loadExtension(firstExtension);
+
+        DiscoveryExtensionNode extension = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300),
+            new HashMap<String, String>(),
+            Version.CURRENT,
+            Version.fromString("2.0.0"),
+            List.of()
+        );
+        DiscoveryExtensionNode initializedExtension = extensionsManager.getExtensionIdMap().get(extension.getId());
+        assertEquals(extension.getName(), initializedExtension.getName());
+        assertEquals(extension.getId(), initializedExtension.getId());
+        assertTrue(extensionsManager.lookupExtensionSettingsById(extension.getId()).isPresent());
+        assertEquals(
+            "custom_setting",
+            extensionsManager.lookupExtensionSettingsById(extension.getId()).get().getAdditionalSettings().get(customSetting)
+        );
+    }
+
+    public void testAdditionalExtensionSettingsForExtensionWithoutCustomSettingSet() throws Exception {
+
+        Set<Setting<?>> additionalSettings = extAwarePlugin.getExtensionSettings().stream().collect(Collectors.toSet());
+        ExtensionScopedSettings extensionScopedSettings = new ExtensionScopedSettings(additionalSettings);
+        Extension firstExtension = new Extension(
+            "secondExtension",
+            "uniqueid2",
+            "127.0.0.0",
+            "9301",
+            "0.0.7",
+            "2.0.0",
+            "2.0.0",
+            List.of(),
+            extensionScopedSettings
+        );
+
+        ExtensionsManager extensionsManager = new ExtensionsManager(additionalSettings);
+        extensionsManager.loadExtension(firstExtension);
+
+        DiscoveryExtensionNode extension = new DiscoveryExtensionNode(
+            "secondExtension",
+            "uniqueid2",
+            new TransportAddress(InetAddress.getByName("127.0.0.1"), 9301),
+            new HashMap<String, String>(),
+            Version.fromString("2.0.0"),
+            Version.fromString("2.0.0"),
+            List.of()
+        );
+        DiscoveryExtensionNode initializedExtension = extensionsManager.getExtensionIdMap().get(extension.getId());
+        assertEquals(extension.getName(), initializedExtension.getName());
+        assertEquals(extension.getId(), initializedExtension.getId());
+        assertTrue(extensionsManager.lookupExtensionSettingsById(extension.getId()).isPresent());
+        assertEquals(
+            "none",
+            extensionsManager.lookupExtensionSettingsById(extension.getId()).get().getAdditionalSettings().get(customSetting)
+        );
+    }
+
+    private void initialize(ExtensionsManager extensionsManager) {
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        extensionsManager.initializeServicesAndRestHandler(
+            actionModule,
+            settingsModule,
+            transportService,
+            clusterService,
+            settings,
+            client
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionActionRequestTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionRequestTests.java
new file mode 100644
index 0000000000000..33ec97cd0f112
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionRequestTests.java
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ExtensionActionRequestTests extends OpenSearchTestCase {
+
+    public void testExtensionActionRequest() throws Exception {
+        String expectedAction = "test-action";
+        ByteString expectedRequestBytes = ByteString.copyFromUtf8("request-bytes");
+        ExtensionActionRequest request = new ExtensionActionRequest(expectedAction, expectedRequestBytes);
+
+        assertEquals(expectedAction, request.getAction());
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        request.writeTo(out);
+        BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()));
+        request = new ExtensionActionRequest(in);
+
+        assertEquals(expectedAction, request.getAction());
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+        assertNull(request.validate());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionActionResponseTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionResponseTests.java
new file mode 100644
index 0000000000000..4ef95d36fb51f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionResponseTests.java
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.charset.StandardCharsets;
+
+public class ExtensionActionResponseTests extends OpenSearchTestCase {
+
+    public void testExtensionActionResponse() throws Exception {
+        byte[] expectedResponseBytes = "response-bytes".getBytes(StandardCharsets.UTF_8);
+        ExtensionActionResponse response = new ExtensionActionResponse(expectedResponseBytes);
+
+        assertEquals(expectedResponseBytes, response.getResponseBytes());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        response.writeTo(out);
+        BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()));
+        response = new ExtensionActionResponse(in);
+        assertArrayEquals(expectedResponseBytes, response.getResponseBytes());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionActionUtilTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionUtilTests.java
new file mode 100644
index 0000000000000..293051e03d883
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionActionUtilTests.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+
+import org.mockito.Mockito;
+
+import static org.opensearch.extensions.action.ExtensionActionUtil.UNIT_SEPARATOR;
+import static org.opensearch.extensions.action.ExtensionActionUtil.createProxyRequestBytes;
+
+public class ExtensionActionUtilTests extends OpenSearchTestCase {
+    private byte[] myBytes;
+    private final String actionName = "org.opensearch.action.MyExampleRequest";
+    private final byte[] actionNameBytes = MyExampleRequest.class.getName().getBytes(StandardCharsets.UTF_8);
+
+    @Before
+    public void setup() throws IOException {
+        BytesStreamOutput out = new BytesStreamOutput();
+        MyExampleRequest exampleRequest = new MyExampleRequest(actionName, actionNameBytes);
+        exampleRequest.writeTo(out);
+
+        byte[] requestBytes = BytesReference.toBytes(out.bytes());
+        byte[] requestClass = MyExampleRequest.class.getName().getBytes(StandardCharsets.UTF_8);
+        this.myBytes = ByteBuffer.allocate(requestClass.length + 1 + requestBytes.length)
+            .put(requestClass)
+            .put(UNIT_SEPARATOR)
+            .put(requestBytes)
+            .array();
+    }
+
+    public void testCreateProxyRequestBytes() throws IOException {
+        BytesStreamOutput out = new BytesStreamOutput();
+        MyExampleRequest exampleRequest = new MyExampleRequest(actionName, actionNameBytes);
+        exampleRequest.writeTo(out);
+
+        byte[] result = createProxyRequestBytes(exampleRequest);
+        assertArrayEquals(this.myBytes, result);
+        assertThrows(RuntimeException.class, () -> ExtensionActionUtil.createProxyRequestBytes(new MyExampleRequest(null, null)));
+    }
+
+    public void testCreateActionRequest() throws ReflectiveOperationException {
+        ActionRequest actionRequest = ExtensionActionUtil.createActionRequest(myBytes);
+        assertThrows(NullPointerException.class, () -> ExtensionActionUtil.createActionRequest(null));
+        assertThrows(ReflectiveOperationException.class, () -> ExtensionActionUtil.createActionRequest(actionNameBytes));
+        assertNotNull(actionRequest);
+        assertFalse(actionRequest.getShouldStoreResult());
+    }
+
+    public void testConvertParamsToBytes() throws IOException {
+        Writeable mockWriteableObject = Mockito.mock(Writeable.class);
+        Mockito.doThrow(new IOException("Test IOException")).when(mockWriteableObject).writeTo(Mockito.any());
+        assertThrows(IllegalStateException.class, () -> ExtensionActionUtil.convertParamsToBytes(mockWriteableObject));
+    }
+
+    public void testDelimPos() {
+        assertTrue(ExtensionActionUtil.delimPos(myBytes) > 0);
+        assertTrue(ExtensionActionUtil.delimPos(actionNameBytes) < 0);
+        assertEquals(-1, ExtensionActionUtil.delimPos(actionNameBytes));
+    }
+
+    private static class MyExampleRequest extends ActionRequest {
+        private final String param1;
+        private final byte[] param2;
+
+        public MyExampleRequest(String param1, byte[] param2) {
+            this.param1 = param1;
+            this.param2 = param2;
+        }
+
+        public MyExampleRequest(StreamInput in) throws IOException {
+            super(in);
+            param1 = in.readString();
+            param2 = in.readByteArray();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(param1);
+            out.writeByteArray(param2);
+        }
+
+        @Override
+        public ActionRequestValidationException validate() {
+            return null;
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionHandleTransportRequestTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionHandleTransportRequestTests.java
new file mode 100644
index 0000000000000..77a86d772a6ca
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionHandleTransportRequestTests.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ExtensionHandleTransportRequestTests extends OpenSearchTestCase {
+    public void testExtensionHandleTransportRequest() throws Exception {
+        String expectedAction = "test-action";
+        ByteString expectedRequestBytes = ByteString.copyFromUtf8("request-bytes");
+        ExtensionHandleTransportRequest request = new ExtensionHandleTransportRequest(expectedAction, expectedRequestBytes);
+
+        assertEquals(expectedAction, request.getAction());
+        logger.info(expectedRequestBytes);
+        logger.info(request.getRequestBytes());
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        request.writeTo(out);
+        BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()));
+        request = new ExtensionHandleTransportRequest(in);
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+        assertEquals(expectedAction, request.getAction());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionProxyActionTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionProxyActionTests.java
new file mode 100644
index 0000000000000..3719c29090287
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionProxyActionTests.java
@@ -0,0 +1,18 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class ExtensionProxyActionTests extends OpenSearchTestCase {
+    public void testExtensionProxyAction() {
+        assertEquals("cluster:internal/extensions", ExtensionProxyAction.NAME);
+        assertEquals(ExtensionProxyAction.class, ExtensionProxyAction.INSTANCE.getClass());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java
new file mode 100644
index 0000000000000..7b9b146734ef4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java
@@ -0,0 +1,181 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.Version;
+import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.extensions.AcknowledgedResponse;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.rest.RestSendToExtensionActionTests;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.client.NoOpNodeClient;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ActionNotFoundTransportException;
+import org.opensearch.transport.NodeNotConnectedException;
+import org.opensearch.transport.TransportService;
+import org.opensearch.transport.nio.MockNioTransport;
+import org.junit.After;
+import org.junit.Before;
+
+import java.net.InetAddress;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ExtensionTransportActionsHandlerTests extends OpenSearchTestCase {
+    private static final ActionFilters EMPTY_FILTERS = new ActionFilters(Collections.emptySet());
+    private TransportService transportService;
+    private MockNioTransport transport;
+    private DiscoveryExtensionNode discoveryExtensionNode;
+    private ExtensionTransportActionsHandler extensionTransportActionsHandler;
+    private NodeClient client;
+    private final ThreadPool threadPool = new TestThreadPool(RestSendToExtensionActionTests.class.getSimpleName());
+
+    @Before
+    public void setup() throws Exception {
+        Settings settings = Settings.builder().put("cluster.name", "test").build();
+        transport = new MockNioTransport(
+            settings,
+            Version.CURRENT,
+            threadPool,
+            new NetworkService(Collections.emptyList()),
+            PageCacheRecycler.NON_RECYCLING_INSTANCE,
+            new NamedWriteableRegistry(Collections.emptyList()),
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
+        );
+        transportService = new MockTransportService(
+            settings,
+            transport,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            (boundAddress) -> new DiscoveryNode(
+                "test_node",
+                "test_node",
+                boundAddress.publishAddress(),
+                emptyMap(),
+                emptySet(),
+                Version.CURRENT
+            ),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        discoveryExtensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<String, String>(),
+            Version.fromString("3.0.0"),
+            Version.CURRENT,
+            Collections.emptyList()
+        );
+        client = new NoOpNodeClient(this.getTestName());
+        ActionModule mockActionModule = mock(ActionModule.class);
+        DynamicActionRegistry dynamicActionRegistry = new DynamicActionRegistry();
+        dynamicActionRegistry.registerUnmodifiableActionMap(Collections.emptyMap());
+        when(mockActionModule.getDynamicActionRegistry()).thenReturn(dynamicActionRegistry);
+        when(mockActionModule.getActionFilters()).thenReturn(EMPTY_FILTERS);
+        extensionTransportActionsHandler = new ExtensionTransportActionsHandler(
+            Map.of("uniqueid1", discoveryExtensionNode),
+            transportService,
+            client,
+            mockActionModule,
+            null
+        );
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        transportService.close();
+        client.close();
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+    }
+
+    public void testRegisterAction() {
+        String action = "test-action";
+        extensionTransportActionsHandler.registerAction(action, discoveryExtensionNode.getId());
+        assertEquals(discoveryExtensionNode, extensionTransportActionsHandler.getExtension(action));
+
+        // Test duplicate action registration
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> extensionTransportActionsHandler.registerAction(action, discoveryExtensionNode.getId())
+        );
+        assertEquals(discoveryExtensionNode, extensionTransportActionsHandler.getExtension(action));
+    }
+
+    public void testRegisterTransportActionsRequest() {
+        String action = "test-action";
+        RegisterTransportActionsRequest request = new RegisterTransportActionsRequest("uniqueid1", Set.of(action));
+        AcknowledgedResponse response = (AcknowledgedResponse) extensionTransportActionsHandler.handleRegisterTransportActionsRequest(
+            request
+        );
+        assertTrue(response.getStatus());
+        assertEquals(discoveryExtensionNode, extensionTransportActionsHandler.getExtension(action));
+
+        // Test duplicate action registration
+        response = (AcknowledgedResponse) extensionTransportActionsHandler.handleRegisterTransportActionsRequest(request);
+        assertFalse(response.getStatus());
+    }
+
+    public void testTransportActionRequestFromExtension() throws Exception {
+        String action = "test-action";
+        ByteString requestBytes = ByteString.copyFromUtf8("requestBytes");
+        TransportActionRequestFromExtension request = new TransportActionRequestFromExtension(action, requestBytes, "uniqueid1");
+        RemoteExtensionActionResponse response = extensionTransportActionsHandler.handleTransportActionRequestFromExtension(request);
+        assertFalse(response.isSuccess());
+        String responseString = response.getResponseBytesAsString();
+        assertEquals("Request failed: action [test-action] is not registered for any extension.", responseString);
+    }
+
+    public void testSendTransportRequestToExtension() throws InterruptedException {
+        String action = "test-action";
+        ByteString requestBytes = ByteString.copyFromUtf8("requestBytes");
+        ExtensionActionRequest request = new ExtensionActionRequest(action, requestBytes);
+
+        // Action not registered, expect exception
+        expectThrows(
+            ActionNotFoundTransportException.class,
+            () -> extensionTransportActionsHandler.sendTransportRequestToExtension(request)
+        );
+
+        // Register Action
+        RegisterTransportActionsRequest registerRequest = new RegisterTransportActionsRequest("uniqueid1", Set.of(action));
+        AcknowledgedResponse response = (AcknowledgedResponse) extensionTransportActionsHandler.handleRegisterTransportActionsRequest(
+            registerRequest
+        );
+        assertTrue(response.getStatus());
+
+        expectThrows(NodeNotConnectedException.class, () -> extensionTransportActionsHandler.sendTransportRequestToExtension(request));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/RegisterTransportActionsRequestTests.java b/server/src/test/java/org/opensearch/extensions/action/RegisterTransportActionsRequestTests.java
new file mode 100644
index 0000000000000..d60bdad8ac6b0
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/RegisterTransportActionsRequestTests.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Set;
+
+public class RegisterTransportActionsRequestTests extends OpenSearchTestCase {
+    private RegisterTransportActionsRequest originalRequest;
+
+    @Before
+    public void setup() {
+        this.originalRequest = new RegisterTransportActionsRequest("extension-uniqueId", Set.of("testAction"));
+    }
+
+    public void testRegisterTransportActionsRequest() throws IOException {
+        BytesStreamOutput output = new BytesStreamOutput();
+        originalRequest.writeTo(output);
+        StreamInput input = output.bytes().streamInput();
+        RegisterTransportActionsRequest parsedRequest = new RegisterTransportActionsRequest(input);
+        assertEquals(parsedRequest.getTransportActions(), originalRequest.getTransportActions());
+        assertEquals(parsedRequest.getTransportActions().size(), originalRequest.getTransportActions().size());
+        assertEquals(parsedRequest.hashCode(), originalRequest.hashCode());
+        assertTrue(originalRequest.equals(parsedRequest));
+    }
+
+    public void testToString() {
+        logger.info(originalRequest.toString());
+        assertEquals(
+            originalRequest.toString(),
+            "TransportActionsRequest{Identity=uniqueId: \"extension-uniqueId\"\n, actions=[testAction]}"
+        );
+    }
+
+    public void testNoIdentityRegisterTransportActionsRequest() {
+        String uniqueId = null;
+        // Expect exception as Extension Identity(uniqueId) is null
+        expectThrows(NullPointerException.class, () -> new RegisterTransportActionsRequest(uniqueId, Set.of()));
+    }
+
+    public void testNoTransportActionsRequest() {
+        String uniqueId = "extension-1234";
+        Set<String> expectedActions = null;
+        // Expect exception as paths are null
+        expectThrows(NullPointerException.class, () -> new RegisterTransportActionsRequest(uniqueId, expectedActions));
+    }
+
+    public void testEmptyTransportActionsRequest() {
+        String uniqueId = "extension-1234";
+        Set<String> expectedActions = Set.of();
+        RegisterTransportActionsRequest request = new RegisterTransportActionsRequest(uniqueId, expectedActions);
+
+        assertEquals(uniqueId, request.getUniqueId());
+        assertEquals(List.of(), request.getTransportActions());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/RemoteExtensionActionResponseTests.java b/server/src/test/java/org/opensearch/extensions/action/RemoteExtensionActionResponseTests.java
new file mode 100644
index 0000000000000..a20405975e6b7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/RemoteExtensionActionResponseTests.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.charset.StandardCharsets;
+
+public class RemoteExtensionActionResponseTests extends OpenSearchTestCase {
+
+    public void testExtensionActionResponse() throws Exception {
+        byte[] expectedResponseBytes = "response-bytes".getBytes(StandardCharsets.UTF_8);
+        RemoteExtensionActionResponse response = new RemoteExtensionActionResponse(true, expectedResponseBytes);
+
+        assertTrue(response.isSuccess());
+        assertEquals(expectedResponseBytes, response.getResponseBytes());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        response.writeTo(out);
+        BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()));
+        response = new RemoteExtensionActionResponse(in);
+
+        assertTrue(response.isSuccess());
+        assertArrayEquals(expectedResponseBytes, response.getResponseBytes());
+    }
+
+    public void testSetters() {
+        String expectedResponse = "response-bytes";
+        byte[] expectedResponseBytes = expectedResponse.getBytes(StandardCharsets.UTF_8);
+        byte[] expectedEmptyBytes = new byte[0];
+        RemoteExtensionActionResponse response = new RemoteExtensionActionResponse(false, expectedEmptyBytes);
+        assertArrayEquals(expectedEmptyBytes, response.getResponseBytes());
+        assertFalse(response.isSuccess());
+
+        response.setResponseBytesAsString(expectedResponse);
+        assertArrayEquals(expectedResponseBytes, response.getResponseBytes());
+
+        response.setResponseBytes(expectedResponseBytes);
+        assertArrayEquals(expectedResponseBytes, response.getResponseBytes());
+        assertEquals(expectedResponse, response.getResponseBytesAsString());
+
+        response.setSuccess(true);
+        assertTrue(response.isSuccess());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/action/TransportActionRequestFromExtensionTests.java b/server/src/test/java/org/opensearch/extensions/action/TransportActionRequestFromExtensionTests.java
new file mode 100644
index 0000000000000..6e9e827fdaf9e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/action/TransportActionRequestFromExtensionTests.java
@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.action;
+
+import com.google.protobuf.ByteString;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class TransportActionRequestFromExtensionTests extends OpenSearchTestCase {
+    public void testTransportActionRequestFromExtension() throws Exception {
+        String expectedAction = "test-action";
+        ByteString expectedRequestBytes = ByteString.copyFromUtf8("request-bytes");
+        String uniqueId = "test-uniqueId";
+        TransportActionRequestFromExtension request = new TransportActionRequestFromExtension(
+            expectedAction,
+            expectedRequestBytes,
+            uniqueId
+        );
+
+        assertEquals(expectedAction, request.getAction());
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+        assertEquals(uniqueId, request.getUniqueId());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        request.writeTo(out);
+        BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()));
+        request = new TransportActionRequestFromExtension(in);
+
+        assertEquals(expectedAction, request.getAction());
+        assertEquals(expectedRequestBytes, request.getRequestBytes());
+        assertEquals(uniqueId, request.getUniqueId());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestRequestTests.java b/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestRequestTests.java
new file mode 100644
index 0000000000000..9b875ce89d587
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestRequestTests.java
@@ -0,0 +1,298 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.charset.StandardCharsets;
+import java.security.Principal;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import static java.util.Map.entry;
+
+public class ExtensionRestRequestTests extends OpenSearchTestCase {
+
+    private Method expectedMethod;
+    private String expectedPath;
+    private String expectedUri;
+    Map<String, String> expectedParams;
+    Map<String, List<String>> expectedHeaders;
+    MediaType expectedContentType;
+    BytesReference expectedContent;
+    String extensionUniqueId1;
+    Principal userPrincipal;
+    HttpRequest.HttpVersion expectedHttpVersion;
+    // Will be replaced with ExtensionTokenProcessor and PrincipalIdentifierToken classes from feature/identity
+    String extensionTokenProcessor;
+    String expectedRequestIssuerIdentity;
+    NamedWriteableRegistry registry;
+
+    public void setUp() throws Exception {
+        super.setUp();
+        expectedMethod = Method.GET;
+        expectedPath = "/test/uri";
+        expectedUri = "foobar?foo=bar&baz=42";
+        expectedParams = Map.ofEntries(entry("foo", "bar"), entry("baz", "42"));
+        expectedHeaders = Map.ofEntries(
+            entry("Content-Type", Arrays.asList("application/json")),
+            entry("foo", Arrays.asList("hello", "world"))
+        );
+        expectedContentType = MediaTypeRegistry.JSON;
+        expectedContent = new BytesArray("{\"key\": \"value\"}".getBytes(StandardCharsets.UTF_8));
+        extensionUniqueId1 = "ext_1";
+        userPrincipal = () -> "user1";
+        expectedHttpVersion = HttpRequest.HttpVersion.HTTP_1_1;
+        extensionTokenProcessor = "placeholder_extension_token_processor";
+        expectedRequestIssuerIdentity = "placeholder_request_issuer_identity";
+    }
+
+    public void testExtensionRestRequest() throws Exception {
+        ExtensionRestRequest request = new ExtensionRestRequest(
+            expectedMethod,
+            expectedUri,
+            expectedPath,
+            expectedParams,
+            expectedHeaders,
+            expectedContentType,
+            expectedContent,
+            expectedRequestIssuerIdentity,
+            expectedHttpVersion
+        );
+
+        assertEquals(expectedMethod, request.method());
+        assertEquals(expectedUri, request.uri());
+        assertEquals(expectedPath, request.path());
+
+        assertEquals(expectedParams, request.params());
+        assertEquals(expectedHttpVersion, request.protocolVersion());
+
+        assertEquals(Collections.emptyList(), request.consumedParams());
+        assertTrue(request.hasParam("foo"));
+        assertFalse(request.hasParam("bar"));
+        assertEquals("bar", request.param("foo"));
+        assertEquals("baz", request.param("bar", "baz"));
+        assertEquals(42L, request.paramAsLong("baz", 0L));
+        assertEquals(0L, request.paramAsLong("bar", 0L));
+        assertTrue(request.consumedParams().contains("foo"));
+        assertTrue(request.consumedParams().contains("baz"));
+
+        assertEquals(expectedContentType, request.getXContentType());
+        assertTrue(request.hasContent());
+        assertFalse(request.isContentConsumed());
+        assertEquals(expectedContent, request.content());
+        assertTrue(request.isContentConsumed());
+
+        XContentParser parser = request.contentParser(NamedXContentRegistry.EMPTY);
+        Map<String, String> contentMap = parser.mapStrings();
+        assertEquals("value", contentMap.get("key"));
+
+        assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                try (NamedWriteableAwareStreamInput nameWritableAwareIn = new NamedWriteableAwareStreamInput(in, registry)) {
+                    request = new ExtensionRestRequest(nameWritableAwareIn);
+                    assertEquals(expectedMethod, request.method());
+                    assertEquals(expectedUri, request.uri());
+                    assertEquals(expectedPath, request.path());
+                    assertEquals(expectedParams, request.params());
+                    assertEquals(expectedHeaders, request.headers());
+                    assertEquals(expectedContent, request.content());
+                    assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+                    assertEquals(expectedHttpVersion, request.protocolVersion());
+                }
+            }
+        }
+    }
+
+    public void testExtensionRestRequestWithNoContent() throws Exception {
+        ExtensionRestRequest request = new ExtensionRestRequest(
+            expectedMethod,
+            expectedUri,
+            expectedPath,
+            expectedParams,
+            expectedHeaders,
+            null,
+            new BytesArray(new byte[0]),
+            expectedRequestIssuerIdentity,
+            expectedHttpVersion
+        );
+
+        assertEquals(expectedMethod, request.method());
+        assertEquals(expectedPath, request.path());
+        assertEquals(expectedParams, request.params());
+        assertEquals(expectedHeaders, request.headers());
+        assertNull(request.getXContentType());
+        assertEquals(0, request.content().length());
+        assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+        assertEquals(expectedHttpVersion, request.protocolVersion());
+
+        final ExtensionRestRequest requestWithNoContent = request;
+        assertThrows(OpenSearchParseException.class, () -> requestWithNoContent.contentParser(NamedXContentRegistry.EMPTY));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                try (NamedWriteableAwareStreamInput nameWritableAwareIn = new NamedWriteableAwareStreamInput(in, registry)) {
+                    request = new ExtensionRestRequest(nameWritableAwareIn);
+                    assertEquals(expectedMethod, request.method());
+                    assertEquals(expectedUri, request.uri());
+                    assertEquals(expectedPath, request.path());
+                    assertEquals(expectedParams, request.params());
+                    assertNull(request.getXContentType());
+                    assertEquals(0, request.content().length());
+                    assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+                    assertEquals(expectedHttpVersion, request.protocolVersion());
+
+                    final ExtensionRestRequest requestWithNoContentType = request;
+                    assertThrows(OpenSearchParseException.class, () -> requestWithNoContentType.contentParser(NamedXContentRegistry.EMPTY));
+                }
+            }
+        }
+    }
+
+    public void testExtensionRestRequestWithPlainTextContent() throws Exception {
+        BytesReference expectedText = new BytesArray("Plain text");
+
+        ExtensionRestRequest request = new ExtensionRestRequest(
+            expectedMethod,
+            expectedUri,
+            expectedPath,
+            expectedParams,
+            expectedHeaders,
+            null,
+            expectedText,
+            expectedRequestIssuerIdentity,
+            expectedHttpVersion
+        );
+
+        assertEquals(expectedMethod, request.method());
+        assertEquals(expectedUri, request.uri());
+        assertEquals(expectedPath, request.path());
+        assertEquals(expectedParams, request.params());
+        assertNull(request.getXContentType());
+        assertEquals(expectedText, request.content());
+        assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+        assertEquals(expectedHttpVersion, request.protocolVersion());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                try (NamedWriteableAwareStreamInput nameWritableAwareIn = new NamedWriteableAwareStreamInput(in, registry)) {
+                    request = new ExtensionRestRequest(nameWritableAwareIn);
+                    assertEquals(expectedMethod, request.method());
+                    assertEquals(expectedUri, request.uri());
+                    assertEquals(expectedPath, request.path());
+                    assertEquals(expectedParams, request.params());
+                    assertNull(request.getXContentType());
+                    assertEquals(expectedText, request.content());
+                    assertEquals(expectedRequestIssuerIdentity, request.getRequestIssuerIdentity());
+                    assertEquals(expectedHttpVersion, request.protocolVersion());
+                }
+            }
+        }
+    }
+
+    public void testRestExecuteOnExtensionResponse() throws Exception {
+        RestStatus expectedStatus = RestStatus.OK;
+        String expectedContentType = BytesRestResponse.TEXT_CONTENT_TYPE;
+        String expectedResponse = "Test response";
+        byte[] expectedResponseBytes = expectedResponse.getBytes(StandardCharsets.UTF_8);
+
+        RestExecuteOnExtensionResponse response = new RestExecuteOnExtensionResponse(
+            expectedStatus,
+            expectedContentType,
+            expectedResponseBytes,
+            Collections.emptyMap(),
+            Collections.emptyList(),
+            false
+        );
+
+        assertEquals(expectedStatus, response.getStatus());
+        assertEquals(expectedContentType, response.getContentType());
+        assertArrayEquals(expectedResponseBytes, response.getContent());
+        assertEquals(0, response.getHeaders().size());
+        assertEquals(0, response.getConsumedParams().size());
+        assertFalse(response.isContentConsumed());
+
+        String headerKey = "foo";
+        List<String> headerValueList = List.of("bar", "baz");
+        Map<String, List<String>> expectedHeaders = Map.of(headerKey, headerValueList);
+        List<String> expectedConsumedParams = List.of("foo", "bar");
+
+        response = new RestExecuteOnExtensionResponse(
+            expectedStatus,
+            expectedContentType,
+            expectedResponseBytes,
+            expectedHeaders,
+            expectedConsumedParams,
+            true
+        );
+
+        assertEquals(expectedStatus, response.getStatus());
+        assertEquals(expectedContentType, response.getContentType());
+        assertArrayEquals(expectedResponseBytes, response.getContent());
+
+        assertEquals(1, response.getHeaders().keySet().size());
+        assertTrue(response.getHeaders().containsKey(headerKey));
+
+        List<String> fooList = response.getHeaders().get(headerKey);
+        assertEquals(2, fooList.size());
+        assertTrue(fooList.containsAll(headerValueList));
+
+        assertEquals(2, response.getConsumedParams().size());
+        assertTrue(response.getConsumedParams().containsAll(expectedConsumedParams));
+        assertTrue(response.isContentConsumed());
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            response.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                response = new RestExecuteOnExtensionResponse(in);
+
+                assertEquals(expectedStatus, response.getStatus());
+                assertEquals(expectedContentType, response.getContentType());
+                assertArrayEquals(expectedResponseBytes, response.getContent());
+
+                assertEquals(1, response.getHeaders().keySet().size());
+                assertTrue(response.getHeaders().containsKey(headerKey));
+
+                fooList = response.getHeaders().get(headerKey);
+                assertEquals(2, fooList.size());
+                assertTrue(fooList.containsAll(headerValueList));
+
+                assertEquals(2, response.getConsumedParams().size());
+                assertTrue(response.getConsumedParams().containsAll(expectedConsumedParams));
+                assertTrue(response.isContentConsumed());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestResponseTests.java b/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestResponseTests.java
new file mode 100644
index 0000000000000..b2d9f698e199c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/rest/ExtensionRestResponseTests.java
@@ -0,0 +1,186 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.http.HttpResponse;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import static org.opensearch.core.rest.RestStatus.ACCEPTED;
+import static org.opensearch.core.rest.RestStatus.OK;
+import static org.opensearch.rest.BytesRestResponse.TEXT_CONTENT_TYPE;
+
+public class ExtensionRestResponseTests extends OpenSearchTestCase {
+
+    private static final String OCTET_CONTENT_TYPE = "application/octet-stream";
+    private static final String JSON_CONTENT_TYPE = "application/json; charset=UTF-8";
+
+    private String testText;
+    private byte[] testBytes;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        testText = "plain text";
+        testBytes = new byte[] { 1, 2 };
+    }
+
+    private RestRequest generateTestRequest() {
+        RestRequest request = RestRequest.request(null, new HttpRequest() {
+
+            @Override
+            public Method method() {
+                return Method.GET;
+            }
+
+            @Override
+            public String uri() {
+                return "/foo";
+            }
+
+            @Override
+            public BytesReference content() {
+                return new BytesArray("Text Content");
+            }
+
+            @Override
+            public Map<String, List<String>> getHeaders() {
+                return Collections.emptyMap();
+            }
+
+            @Override
+            public List<String> strictCookies() {
+                return Collections.emptyList();
+            }
+
+            @Override
+            public HttpVersion protocolVersion() {
+                return null;
+            }
+
+            @Override
+            public HttpRequest removeHeader(String header) {
+                // we don't use
+                return null;
+            }
+
+            @Override
+            public HttpResponse createResponse(RestStatus status, BytesReference content) {
+                return null;
+            }
+
+            @Override
+            public Exception getInboundException() {
+                return null;
+            }
+
+            @Override
+            public void release() {}
+
+            @Override
+            public HttpRequest releaseAndCopy() {
+                return null;
+            }
+        }, null);
+        // consume params "foo" and "bar"
+        request.param("foo");
+        request.param("bar");
+        // consume content
+        request.content();
+        return request;
+    }
+
+    public void testConstructorWithBuilder() throws IOException {
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
+        builder.startObject();
+        builder.field("status", ACCEPTED);
+        builder.endObject();
+        RestRequest request = generateTestRequest();
+        ExtensionRestResponse response = new ExtensionRestResponse(request, OK, builder);
+
+        assertEquals(OK, response.status());
+        assertEquals(JSON_CONTENT_TYPE, response.contentType());
+        assertEquals("{\"status\":\"ACCEPTED\"}", response.content().utf8ToString());
+        for (String param : response.getConsumedParams()) {
+            assertTrue(request.consumedParams().contains(param));
+        }
+        assertTrue(request.isContentConsumed());
+    }
+
+    public void testConstructorWithPlainText() {
+        RestRequest request = generateTestRequest();
+        ExtensionRestResponse response = new ExtensionRestResponse(request, OK, testText);
+
+        assertEquals(OK, response.status());
+        assertEquals(TEXT_CONTENT_TYPE, response.contentType());
+        assertEquals(testText, response.content().utf8ToString());
+        for (String param : response.getConsumedParams()) {
+            assertTrue(request.consumedParams().contains(param));
+        }
+        assertTrue(request.isContentConsumed());
+    }
+
+    public void testConstructorWithText() {
+        RestRequest request = generateTestRequest();
+        ExtensionRestResponse response = new ExtensionRestResponse(request, OK, TEXT_CONTENT_TYPE, testText);
+
+        assertEquals(OK, response.status());
+        assertEquals(TEXT_CONTENT_TYPE, response.contentType());
+        assertEquals(testText, response.content().utf8ToString());
+
+        for (String param : response.getConsumedParams()) {
+            assertTrue(request.consumedParams().contains(param));
+        }
+        assertTrue(request.isContentConsumed());
+    }
+
+    public void testConstructorWithByteArray() {
+        RestRequest request = generateTestRequest();
+        ExtensionRestResponse response = new ExtensionRestResponse(request, OK, OCTET_CONTENT_TYPE, testBytes);
+
+        assertEquals(OK, response.status());
+        assertEquals(OCTET_CONTENT_TYPE, response.contentType());
+        assertArrayEquals(testBytes, BytesReference.toBytes(response.content()));
+        for (String param : response.getConsumedParams()) {
+            assertTrue(request.consumedParams().contains(param));
+        }
+        assertTrue(request.isContentConsumed());
+    }
+
+    public void testConstructorWithBytesReference() {
+        RestRequest request = generateTestRequest();
+        ExtensionRestResponse response = new ExtensionRestResponse(
+            request,
+            OK,
+            OCTET_CONTENT_TYPE,
+            BytesReference.fromByteBuffer(ByteBuffer.wrap(testBytes, 0, 2))
+        );
+
+        assertEquals(OK, response.status());
+        assertEquals(OCTET_CONTENT_TYPE, response.contentType());
+        assertArrayEquals(testBytes, BytesReference.toBytes(response.content()));
+        for (String param : response.getConsumedParams()) {
+            assertTrue(request.consumedParams().contains(param));
+        }
+        assertTrue(request.isContentConsumed());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/rest/RegisterRestActionsTests.java b/server/src/test/java/org/opensearch/extensions/rest/RegisterRestActionsTests.java
new file mode 100644
index 0000000000000..de40347b8b391
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/rest/RegisterRestActionsTests.java
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+
+public class RegisterRestActionsTests extends OpenSearchTestCase {
+
+    public void testRegisterRestActionsRequest() throws Exception {
+        String uniqueIdStr = "uniqueid1";
+        List<String> expected = List.of("GET /foo", "PUT /bar", "POST /baz");
+        List<String> expectedDeprecated = List.of("GET /deprecated/foo", "It's deprecated");
+        RegisterRestActionsRequest registerRestActionsRequest = new RegisterRestActionsRequest(uniqueIdStr, expected, expectedDeprecated);
+
+        assertEquals(uniqueIdStr, registerRestActionsRequest.getUniqueId());
+        List<String> restActions = registerRestActionsRequest.getRestActions();
+        List<String> deprecatedRestActions = registerRestActionsRequest.getDeprecatedRestActions();
+        assertEquals(expected.size(), restActions.size());
+        assertTrue(restActions.containsAll(expected));
+        assertTrue(expected.containsAll(restActions));
+        assertTrue(expectedDeprecated.containsAll(deprecatedRestActions));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            registerRestActionsRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                registerRestActionsRequest = new RegisterRestActionsRequest(in);
+
+                assertEquals(uniqueIdStr, registerRestActionsRequest.getUniqueId());
+                restActions = registerRestActionsRequest.getRestActions();
+                deprecatedRestActions = registerRestActionsRequest.getDeprecatedRestActions();
+                assertEquals(expected.size(), restActions.size());
+                assertTrue(restActions.containsAll(expected));
+                assertTrue(expected.containsAll(restActions));
+                assertTrue(expectedDeprecated.containsAll(deprecatedRestActions));
+            }
+        }
+    }
+
+    public void testNoIdentityRestActionsRequest() {
+        String uniqueId = null;
+        List<String> expected = List.of("GET /foo", "PUT /bar", "POST /baz");
+        List<String> expectedDeprecated = List.of("GET /deprecated/foo", "It's deprecated");
+        // Expect exception as Extension Identity(uniqueId) is null
+        expectThrows(NullPointerException.class, () -> new RegisterRestActionsRequest(uniqueId, expected, expectedDeprecated));
+    }
+
+    public void testNoRestActionsRequest() {
+        String uniqueId = "extension-1234";
+        List<String> expected = null;
+        List<String> expectedDeprecated = null;
+        // Expect exception as paths are null
+        expectThrows(NullPointerException.class, () -> new RegisterRestActionsRequest(uniqueId, expected, expectedDeprecated));
+    }
+
+    public void testEmptyRestActionsRequest() {
+        String uniqueId = "extension-1234";
+        List<String> expected = List.of();
+        List<String> expectedDeprecated = List.of();
+        RegisterRestActionsRequest request = new RegisterRestActionsRequest(uniqueId, expected, expectedDeprecated);
+
+        assertEquals(uniqueId, request.getUniqueId());
+        assertEquals(List.of(), request.getRestActions());
+        assertEquals(List.of(), request.getDeprecatedRestActions());
+        assertEquals(
+            "RestActionsRequest{Identity=uniqueId: \"extension-1234\"\n" + ", restActions=[], deprecatedRestActions=[]}",
+            request.toString()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/rest/RestInitializeExtensionActionTests.java b/server/src/test/java/org/opensearch/extensions/rest/RestInitializeExtensionActionTests.java
new file mode 100644
index 0000000000000..e6be2be870361
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/rest/RestInitializeExtensionActionTests.java
@@ -0,0 +1,240 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.extensions.ExtensionsSettings.Extension;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.rest.FakeRestChannel;
+import org.opensearch.test.rest.FakeRestRequest;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.opensearch.transport.nio.MockNioTransport;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
+
+import org.mockito.Mockito;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+public class RestInitializeExtensionActionTests extends OpenSearchTestCase {
+
+    private TransportService transportService;
+    private MockNioTransport transport;
+    private final ThreadPool threadPool = new TestThreadPool(RestInitializeExtensionActionTests.class.getSimpleName());
+
+    @Before
+    public void setup() throws Exception {
+        Settings settings = Settings.builder().put("cluster.name", "test").build();
+        transport = new MockNioTransport(
+            settings,
+            Version.CURRENT,
+            threadPool,
+            new NetworkService(Collections.emptyList()),
+            PageCacheRecycler.NON_RECYCLING_INSTANCE,
+            new NamedWriteableRegistry(Collections.emptyList()),
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
+        );
+        transportService = new MockTransportService(
+            settings,
+            transport,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            (boundAddress) -> new DiscoveryNode(
+                "test_node",
+                "test_node",
+                boundAddress.publishAddress(),
+                emptyMap(),
+                emptySet(),
+                Version.CURRENT
+            ),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        transportService.close();
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+    }
+
+    public void testRestInitializeExtensionActionResponse() throws Exception {
+        ExtensionsManager extensionsManager = mock(ExtensionsManager.class);
+        RestInitializeExtensionAction restInitializeExtensionAction = new RestInitializeExtensionAction(extensionsManager);
+        final String content = "{\"name\":\"ad-extension\",\"uniqueId\":\"ad-extension\",\"hostAddress\":\"127.0.0.1\","
+            + "\"port\":\"4532\",\"version\":\"1.0\",\"opensearchVersion\":\""
+            + Version.CURRENT.toString()
+            + "\","
+            + "\"minimumCompatibleVersion\":\""
+            + Version.CURRENT.minimumCompatibilityVersion().toString()
+            + "\"}";
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .withMethod(RestRequest.Method.POST)
+            .build();
+
+        FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+        restInitializeExtensionAction.handleRequest(request, channel, null);
+
+        assertEquals(channel.capturedResponse().status(), RestStatus.ACCEPTED);
+        assertTrue(channel.capturedResponse().content().utf8ToString().contains("A request to initialize an extension has been sent."));
+    }
+
+    public void testRestInitializeExtensionActionFailure() throws Exception {
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of());
+        RestInitializeExtensionAction restInitializeExtensionAction = new RestInitializeExtensionAction(extensionsManager);
+
+        final String content = "{\"name\":\"ad-extension\",\"uniqueId\":\"\",\"hostAddress\":\"127.0.0.1\","
+            + "\"port\":\"4532\",\"version\":\"1.0\",\"opensearchVersion\":\""
+            + Version.CURRENT.toString()
+            + "\","
+            + "\"minimumCompatibleVersion\":\""
+            + Version.CURRENT.minimumCompatibilityVersion().toString()
+            + "\"}";
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .withMethod(RestRequest.Method.POST)
+            .build();
+
+        FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+        restInitializeExtensionAction.handleRequest(request, channel, null);
+
+        assertEquals(1, channel.errors().get());
+        assertTrue(
+            channel.capturedResponse().content().utf8ToString().contains("Required field [extension uniqueId] is missing in the request")
+        );
+    }
+
+    public void testRestInitializeExtensionActionResponseWithAdditionalSettings() throws Exception {
+        Setting boolSetting = Setting.boolSetting("boolSetting", false, Setting.Property.ExtensionScope);
+        Setting stringSetting = Setting.simpleString("stringSetting", "default", Setting.Property.ExtensionScope);
+        Setting intSetting = Setting.intSetting("intSetting", 0, Setting.Property.ExtensionScope);
+        Setting listSetting = Setting.listSetting(
+            "listSetting",
+            List.of("first", "second", "third"),
+            Function.identity(),
+            Setting.Property.ExtensionScope
+        );
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of(boolSetting, stringSetting, intSetting, listSetting));
+        ExtensionsManager spy = spy(extensionsManager);
+
+        // optionally, you can stub out some methods:
+        when(spy.getAdditionalSettings()).thenCallRealMethod();
+        Mockito.doCallRealMethod().when(spy).loadExtension(any(Extension.class));
+        Mockito.doNothing().when(spy).initializeExtensionNode(any(DiscoveryExtensionNode.class));
+        RestInitializeExtensionAction restInitializeExtensionAction = new RestInitializeExtensionAction(spy);
+        final String content = "{\"name\":\"ad-extension\",\"uniqueId\":\"ad-extension\",\"hostAddress\":\"127.0.0.1\","
+            + "\"port\":\"4532\",\"version\":\"1.0\",\"opensearchVersion\":\""
+            + Version.CURRENT.toString()
+            + "\","
+            + "\"minimumCompatibleVersion\":\""
+            + Version.CURRENT.minimumCompatibilityVersion().toString()
+            + "\",\"boolSetting\":true,\"stringSetting\":\"customSetting\",\"intSetting\":5,\"listSetting\":[\"one\",\"two\",\"three\"]}";
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .withMethod(RestRequest.Method.POST)
+            .build();
+
+        FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+        restInitializeExtensionAction.handleRequest(request, channel, null);
+
+        assertEquals(RestStatus.ACCEPTED, channel.capturedResponse().status());
+        assertTrue(channel.capturedResponse().content().utf8ToString().contains("A request to initialize an extension has been sent."));
+
+        Optional<Extension> extension = spy.lookupExtensionSettingsById("ad-extension");
+        assertTrue(extension.isPresent());
+        assertEquals(true, extension.get().getAdditionalSettings().get(boolSetting));
+        assertEquals("customSetting", extension.get().getAdditionalSettings().get(stringSetting));
+        assertEquals(5, extension.get().getAdditionalSettings().get(intSetting));
+
+        List<String> listSettingValue = (List<String>) extension.get().getAdditionalSettings().get(listSetting);
+        assertTrue(listSettingValue.contains("one"));
+        assertTrue(listSettingValue.contains("two"));
+        assertTrue(listSettingValue.contains("three"));
+    }
+
+    public void testRestInitializeExtensionActionResponseWithAdditionalSettingsUsingDefault() throws Exception {
+        Setting boolSetting = Setting.boolSetting("boolSetting", false, Setting.Property.ExtensionScope);
+        Setting stringSetting = Setting.simpleString("stringSetting", "default", Setting.Property.ExtensionScope);
+        Setting intSetting = Setting.intSetting("intSetting", 0, Setting.Property.ExtensionScope);
+        Setting listSetting = Setting.listSetting(
+            "listSetting",
+            List.of("first", "second", "third"),
+            Function.identity(),
+            Setting.Property.ExtensionScope
+        );
+        ExtensionsManager extensionsManager = new ExtensionsManager(Set.of(boolSetting, stringSetting, intSetting, listSetting));
+        ExtensionsManager spy = spy(extensionsManager);
+
+        // optionally, you can stub out some methods:
+        when(spy.getAdditionalSettings()).thenCallRealMethod();
+        Mockito.doCallRealMethod().when(spy).loadExtension(any(Extension.class));
+        Mockito.doNothing().when(spy).initializeExtensionNode(any(DiscoveryExtensionNode.class));
+        RestInitializeExtensionAction restInitializeExtensionAction = new RestInitializeExtensionAction(spy);
+        final String content = "{\"name\":\"ad-extension\",\"uniqueId\":\"ad-extension\",\"hostAddress\":\"127.0.0.1\","
+            + "\"port\":\"4532\",\"version\":\"1.0\",\"opensearchVersion\":\""
+            + Version.CURRENT.toString()
+            + "\","
+            + "\"minimumCompatibleVersion\":\""
+            + Version.CURRENT.minimumCompatibilityVersion().toString()
+            + "\"}";
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .withMethod(RestRequest.Method.POST)
+            .build();
+
+        FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+        restInitializeExtensionAction.handleRequest(request, channel, null);
+
+        assertEquals(RestStatus.ACCEPTED, channel.capturedResponse().status());
+        assertTrue(channel.capturedResponse().content().utf8ToString().contains("A request to initialize an extension has been sent."));
+
+        Optional<Extension> extension = spy.lookupExtensionSettingsById("ad-extension");
+        assertTrue(extension.isPresent());
+        assertEquals(false, extension.get().getAdditionalSettings().get(boolSetting));
+        assertEquals("default", extension.get().getAdditionalSettings().get(stringSetting));
+        assertEquals(0, extension.get().getAdditionalSettings().get(intSetting));
+
+        List<String> listSettingValue = (List<String>) extension.get().getAdditionalSettings().get(listSetting);
+        assertTrue(listSettingValue.contains("first"));
+        assertTrue(listSettingValue.contains("second"));
+        assertTrue(listSettingValue.contains("third"));
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/extensions/rest/RestSendToExtensionActionTests.java b/server/src/test/java/org/opensearch/extensions/rest/RestSendToExtensionActionTests.java
new file mode 100644
index 0000000000000..0fb8c146e8ba4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/rest/RestSendToExtensionActionTests.java
@@ -0,0 +1,452 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.Version;
+import org.opensearch.action.ActionModule;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
+import org.opensearch.action.admin.cluster.health.ClusterHealthAction;
+import org.opensearch.action.admin.cluster.health.TransportClusterHealthAction;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsModule;
+import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.extensions.DiscoveryExtensionNode;
+import org.opensearch.extensions.ExtensionsManager;
+import org.opensearch.extensions.action.ExtensionAction;
+import org.opensearch.extensions.action.ExtensionTransportAction;
+import org.opensearch.identity.IdentityService;
+import org.opensearch.rest.NamedRoute;
+import org.opensearch.rest.RestHandler.Route;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.opensearch.transport.nio.MockNioTransport;
+import org.opensearch.usage.UsageService;
+import org.junit.After;
+import org.junit.Before;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.mockito.Mockito.mock;
+
+public class RestSendToExtensionActionTests extends OpenSearchTestCase {
+
+    private TransportService transportService;
+    private MockNioTransport transport;
+    private DiscoveryExtensionNode discoveryExtensionNode;
+    private ActionModule actionModule;
+    private DynamicActionRegistry dynamicActionRegistry;
+    private final ThreadPool threadPool = new TestThreadPool(RestSendToExtensionActionTests.class.getSimpleName());
+
+    @Before
+    public void setup() throws Exception {
+        Settings settings = Settings.builder().put("cluster.name", "test").build();
+        transport = new MockNioTransport(
+            settings,
+            Version.CURRENT,
+            threadPool,
+            new NetworkService(Collections.emptyList()),
+            PageCacheRecycler.NON_RECYCLING_INSTANCE,
+            new NamedWriteableRegistry(Collections.emptyList()),
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
+        );
+        transportService = new MockTransportService(
+            settings,
+            transport,
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            (boundAddress) -> new DiscoveryNode(
+                "test_node",
+                "test_node",
+                boundAddress.publishAddress(),
+                emptyMap(),
+                emptySet(),
+                Version.CURRENT
+            ),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        discoveryExtensionNode = new DiscoveryExtensionNode(
+            "firstExtension",
+            "uniqueid1",
+            new TransportAddress(InetAddress.getByName("127.0.0.0"), 9300),
+            new HashMap<String, String>(),
+            Version.CURRENT,
+            Version.CURRENT,
+            Collections.emptyList()
+        );
+        SettingsModule settingsModule = new SettingsModule(settings);
+        UsageService usageService = new UsageService();
+        actionModule = new ActionModule(
+            settingsModule.getSettings(),
+            new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY)),
+            settingsModule.getIndexScopedSettings(),
+            settingsModule.getClusterSettings(),
+            settingsModule.getSettingsFilter(),
+            mock(ThreadPool.class),
+            emptyList(),
+            null,
+            null,
+            usageService,
+            null,
+            new IdentityService(Settings.EMPTY, new ArrayList<>()),
+            new ExtensionsManager(Set.of())
+        );
+        dynamicActionRegistry = actionModule.getDynamicActionRegistry();
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        transportService.close();
+        ThreadPool.terminate(threadPool, 30, TimeUnit.SECONDS);
+    }
+
+    public void testRestSendToExtensionAction() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo foo", "PUT /bar bar", "POST /baz baz"),
+            List.of("GET /deprecated/foo foo_deprecated", "Its deprecated")
+        );
+        RestSendToExtensionAction restSendToExtensionAction = new RestSendToExtensionAction(
+            registerRestActionRequest,
+            discoveryExtensionNode,
+            transportService,
+            dynamicActionRegistry
+        );
+
+        assertEquals("uniqueid1:send_to_extension_action", restSendToExtensionAction.getName());
+        List<Route> expected = new ArrayList<>();
+        String uriPrefix = "/_extensions/_uniqueid1";
+        expected.add(new Route(Method.GET, uriPrefix + "/foo"));
+        expected.add(new Route(Method.PUT, uriPrefix + "/bar"));
+        expected.add(new Route(Method.POST, uriPrefix + "/baz"));
+
+        List<Route> routes = restSendToExtensionAction.routes();
+        assertEquals(expected.size(), routes.size());
+        List<String> expectedPaths = expected.stream().map(Route::getPath).collect(Collectors.toList());
+        List<String> paths = routes.stream().map(Route::getPath).collect(Collectors.toList());
+        List<Method> expectedMethods = expected.stream().map(Route::getMethod).collect(Collectors.toList());
+        List<Method> methods = routes.stream().map(Route::getMethod).collect(Collectors.toList());
+        assertTrue(paths.containsAll(expectedPaths));
+        assertTrue(expectedPaths.containsAll(paths));
+        assertTrue(methods.containsAll(expectedMethods));
+        assertTrue(expectedMethods.containsAll(methods));
+    }
+
+    public void testRestSendToExtensionActionWithNamedRoute() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo foo", "PUT /bar bar", "POST /baz baz"),
+            List.of("GET /deprecated/foo foo_deprecated", "It's deprecated!")
+        );
+        RestSendToExtensionAction restSendToExtensionAction = new RestSendToExtensionAction(
+            registerRestActionRequest,
+            discoveryExtensionNode,
+            transportService,
+            dynamicActionRegistry
+        );
+
+        assertEquals("uniqueid1:send_to_extension_action", restSendToExtensionAction.getName());
+        List<NamedRoute> expected = new ArrayList<>();
+        String uriPrefix = "/_extensions/_uniqueid1";
+        NamedRoute nr1 = new NamedRoute.Builder().method(Method.GET).path(uriPrefix + "/foo").uniqueName("foo").build();
+
+        NamedRoute nr2 = new NamedRoute.Builder().method(Method.PUT).path(uriPrefix + "/bar").uniqueName("bar").build();
+
+        NamedRoute nr3 = new NamedRoute.Builder().method(Method.POST).path(uriPrefix + "/baz").uniqueName("baz").build();
+
+        expected.add(nr1);
+        expected.add(nr2);
+        expected.add(nr3);
+
+        List<Route> routes = restSendToExtensionAction.routes();
+        assertEquals(expected.size(), routes.size());
+        List<String> expectedPaths = expected.stream().map(Route::getPath).collect(Collectors.toList());
+        List<String> paths = routes.stream().map(Route::getPath).collect(Collectors.toList());
+        List<Method> expectedMethods = expected.stream().map(Route::getMethod).collect(Collectors.toList());
+        List<Method> methods = routes.stream().map(Route::getMethod).collect(Collectors.toList());
+        List<String> expectedNames = expected.stream().map(NamedRoute::name).collect(Collectors.toList());
+        List<String> names = routes.stream().map(r -> ((NamedRoute) r).name()).collect(Collectors.toList());
+        assertTrue(paths.containsAll(expectedPaths));
+        assertTrue(expectedPaths.containsAll(paths));
+        assertTrue(methods.containsAll(expectedMethods));
+        assertTrue(expectedMethods.containsAll(methods));
+        assertTrue(expectedNames.containsAll(names));
+    }
+
+    public void testRestSendToExtensionActionWithNamedRouteAndLegacyActionName() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of(
+                "GET /foo foo cluster:admin/opensearch/abc/foo",
+                "PUT /bar bar cluster:admin/opensearch/jkl/bar,cluster:admin/opendistro/mno/bar*",
+                "POST /baz baz cluster:admin/opensearch/xyz/baz"
+            ),
+            List.of("GET /deprecated/foo foo_deprecated cluster:admin/opensearch/abc/foo_deprecated", "It's deprecated!")
+        );
+        RestSendToExtensionAction restSendToExtensionAction = new RestSendToExtensionAction(
+            registerRestActionRequest,
+            discoveryExtensionNode,
+            transportService,
+            dynamicActionRegistry
+        );
+
+        assertEquals("uniqueid1:send_to_extension_action", restSendToExtensionAction.getName());
+        List<NamedRoute> expected = new ArrayList<>();
+        String uriPrefix = "/_extensions/_uniqueid1";
+        NamedRoute nr1 = new NamedRoute.Builder().method(Method.GET)
+            .path(uriPrefix + "/foo")
+            .uniqueName("foo")
+            .legacyActionNames(Set.of("cluster:admin/opensearch/abc/foo"))
+            .build();
+        NamedRoute nr2 = new NamedRoute.Builder().method(Method.PUT)
+            .path(uriPrefix + "/bar")
+            .uniqueName("bar")
+            .legacyActionNames(Set.of("cluster:admin/opensearch/jkl/bar", "cluster:admin/opendistro/mno/bar*"))
+            .build();
+        NamedRoute nr3 = new NamedRoute.Builder().method(Method.POST)
+            .path(uriPrefix + "/baz")
+            .uniqueName("baz")
+            .legacyActionNames(Set.of("cluster:admin/opensearch/xyz/baz"))
+            .build();
+
+        expected.add(nr1);
+        expected.add(nr2);
+        expected.add(nr3);
+
+        List<Route> routes = restSendToExtensionAction.routes();
+        assertEquals(expected.size(), routes.size());
+        List<String> expectedPaths = expected.stream().map(Route::getPath).collect(Collectors.toList());
+        List<String> paths = routes.stream().map(Route::getPath).collect(Collectors.toList());
+        List<Method> expectedMethods = expected.stream().map(Route::getMethod).collect(Collectors.toList());
+        List<Method> methods = routes.stream().map(Route::getMethod).collect(Collectors.toList());
+        List<String> expectedNames = expected.stream().map(NamedRoute::name).collect(Collectors.toList());
+        List<String> names = routes.stream().map(r -> ((NamedRoute) r).name()).collect(Collectors.toList());
+        Set<String> expectedActionNames = expected.stream().flatMap(nr -> nr.actionNames().stream()).collect(Collectors.toSet());
+        Set<String> actionNames = routes.stream().flatMap(nr -> ((NamedRoute) nr).actionNames().stream()).collect(Collectors.toSet());
+        assertTrue(paths.containsAll(expectedPaths));
+        assertTrue(expectedPaths.containsAll(paths));
+        assertTrue(methods.containsAll(expectedMethods));
+        assertTrue(expectedMethods.containsAll(methods));
+        assertTrue(expectedNames.containsAll(names));
+        assertTrue(expectedActionNames.containsAll(actionNames));
+    }
+
+    public void testRestSendToExtensionActionWithoutUniqueNameShouldFail() {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo", "PUT /bar"),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionMultipleNamedRoutesWithSameName() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo foo", "PUT /bar foo"),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionMultipleNamedRoutesWithSameLegacyActionName() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo foo cluster:admin/opensearch/abc/foo", "PUT /bar bar cluster:admin/opensearch/abc/foo"),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionMultipleRoutesWithSameMethodAndPath() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo", "GET /foo"),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionMultipleRoutesWithSameMethodAndPathWithDifferentPathParams() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo/{path_param1} fooWithParam", "GET /foo/{path_param2} listFooWithParam"),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionMultipleRoutesWithSameMethodAndPathWithPathParams() {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo/{path_param} fooWithParam", "GET /foo/{path_param}/list listFooWithParam"),
+            List.of()
+        );
+
+        try {
+            new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry);
+        } catch (IllegalArgumentException e) {
+            fail("IllegalArgumentException should not be thrown for different paths");
+        }
+    }
+
+    public void testRestSendToExtensionWithNamedRouteCollidingWithDynamicTransportAction() throws Exception {
+        DynamicActionRegistry dynamicActionRegistry = actionModule.getDynamicActionRegistry();
+        ActionFilters emptyFilters = new ActionFilters(Collections.emptySet());
+        ExtensionAction testExtensionAction = new ExtensionAction("extensionId", "test:action/name");
+        ExtensionTransportAction testExtensionTransportAction = new ExtensionTransportAction("test:action/name", emptyFilters, null, null);
+        assertNull(dynamicActionRegistry.get(testExtensionAction));
+        dynamicActionRegistry.registerDynamicAction(testExtensionAction, testExtensionTransportAction);
+
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo test:action/name"),
+            List.of()
+        );
+
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionWithNamedRouteCollidingWithNativeTransportAction() throws Exception {
+        actionModule.getDynamicActionRegistry()
+            .registerUnmodifiableActionMap(Map.of(ClusterHealthAction.INSTANCE, mock(TransportClusterHealthAction.class)));
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo " + ClusterHealthAction.NAME),
+            List.of()
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionActionFilterHeaders() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo foo", "PUT /bar bar", "POST /baz baz"),
+            List.of("GET /deprecated/foo foo_deprecated", "It's deprecated!")
+        );
+        RestSendToExtensionAction restSendToExtensionAction = new RestSendToExtensionAction(
+            registerRestActionRequest,
+            discoveryExtensionNode,
+            transportService,
+            dynamicActionRegistry
+        );
+
+        Map<String, List<String>> headers = new HashMap<>();
+        headers.put("Content-Type", Arrays.asList("application/json"));
+        headers.put("Authorization", Arrays.asList("Bearer token"));
+        headers.put("Proxy-Authorization", Arrays.asList("Basic credentials"));
+
+        Set<String> allowList = Set.of("Content-Type"); // allowed headers
+        Set<String> denyList = Set.of("Authorization", "Proxy-Authorization"); // denied headers
+
+        Map<String, List<String>> filteredHeaders = restSendToExtensionAction.filterHeaders(headers, allowList, denyList);
+
+        assertTrue(filteredHeaders.containsKey("Content-Type"));
+        assertFalse(filteredHeaders.containsKey("Authorization"));
+        assertFalse(filteredHeaders.containsKey("Proxy-Authorization"));
+    }
+
+    public void testRestSendToExtensionActionBadMethod() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("/foo", "PUT /bar", "POST /baz"),
+            List.of("GET /deprecated/foo", "It's deprecated!")
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionActionBadDeprecatedMethod() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo", "PUT /bar", "POST /baz"),
+            List.of("/deprecated/foo", "It's deprecated!")
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionActionMissingUri() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET", "PUT /bar", "POST /baz"),
+            List.of("GET /deprecated/foo", "It's deprecated!")
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+
+    public void testRestSendToExtensionActionMissingDeprecatedUri() throws Exception {
+        RegisterRestActionsRequest registerRestActionRequest = new RegisterRestActionsRequest(
+            "uniqueid1",
+            List.of("GET /foo", "PUT /bar", "POST /baz"),
+            List.of("GET", "It's deprecated!")
+        );
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new RestSendToExtensionAction(registerRestActionRequest, discoveryExtensionNode, transportService, dynamicActionRegistry)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/extensions/settings/RegisterCustomSettingsTests.java b/server/src/test/java/org/opensearch/extensions/settings/RegisterCustomSettingsTests.java
new file mode 100644
index 0000000000000..ec752073a9055
--- /dev/null
+++ b/server/src/test/java/org/opensearch/extensions/settings/RegisterCustomSettingsTests.java
@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.settings;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Setting.Property;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStreamInput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+public class RegisterCustomSettingsTests extends OpenSearchTestCase {
+
+    public void testRegisterCustomSettingsRequest() throws Exception {
+        String uniqueIdStr = "uniqueid1";
+        List<Setting<?>> expected = List.of(
+            Setting.boolSetting("falseSetting", false, Property.IndexScope, Property.NodeScope),
+            Setting.simpleString("fooSetting", "foo", Property.Dynamic),
+            Setting.timeSetting("timeSetting", new TimeValue(5, TimeUnit.MILLISECONDS), Property.Dynamic),
+            Setting.byteSizeSetting("byteSizeSetting", new ByteSizeValue(10, ByteSizeUnit.KB), Property.Dynamic)
+        );
+        RegisterCustomSettingsRequest registerCustomSettingsRequest = new RegisterCustomSettingsRequest(uniqueIdStr, expected);
+
+        assertEquals(uniqueIdStr, registerCustomSettingsRequest.getUniqueId());
+        List<Setting<?>> settings = registerCustomSettingsRequest.getSettings();
+        assertEquals(expected.size(), settings.size());
+        assertTrue(settings.containsAll(expected));
+        assertTrue(expected.containsAll(settings));
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            registerCustomSettingsRequest.writeTo(out);
+            out.flush();
+            try (BytesStreamInput in = new BytesStreamInput(BytesReference.toBytes(out.bytes()))) {
+                registerCustomSettingsRequest = new RegisterCustomSettingsRequest(in);
+
+                assertEquals(uniqueIdStr, registerCustomSettingsRequest.getUniqueId());
+                settings = registerCustomSettingsRequest.getSettings();
+                assertEquals(expected.size(), settings.size());
+                assertTrue(settings.containsAll(expected));
+                assertTrue(expected.containsAll(settings));
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/gateway/AsyncShardFetchTests.java b/server/src/test/java/org/opensearch/gateway/AsyncShardFetchTests.java
index 1af5a63e344d0..31a27503069d7 100644
--- a/server/src/test/java/org/opensearch/gateway/AsyncShardFetchTests.java
+++ b/server/src/test/java/org/opensearch/gateway/AsyncShardFetchTests.java
@@ -38,7 +38,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -433,7 +433,7 @@ public void run() {
                         try {
                             entry = simulations.get(nodeId);
                             if (entry == null) {
-                                // we are simulating a master node switch, wait for it to not be null
+                                // we are simulating a cluster-manager node switch, wait for it to not be null
                                 assertBusy(() -> assertTrue(simulations.containsKey(nodeId)));
                             }
                             assert entry != null;
diff --git a/server/src/test/java/org/opensearch/gateway/ClusterStateUpdatersTests.java b/server/src/test/java/org/opensearch/gateway/ClusterStateUpdatersTests.java
index 1f63dff04b3df..9b3fd45245ef7 100644
--- a/server/src/test/java/org/opensearch/gateway/ClusterStateUpdatersTests.java
+++ b/server/src/test/java/org/opensearch/gateway/ClusterStateUpdatersTests.java
@@ -40,6 +40,10 @@
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.routing.IndexRoutingTable;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.ClusterSettings;
@@ -47,11 +51,13 @@
 import org.opensearch.common.settings.SettingUpgrader;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.repositories.IndexId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Set;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
@@ -269,6 +275,320 @@ public void testUpdateRoutingTable() {
         }
     }
 
+    public void testSkipRoutingTableUpdateWhenRemoteRecovery() {
+        final int numOfShards = randomIntBetween(1, 10);
+
+        final IndexMetadata remoteMetadata = createIndexMetadata(
+            "test-remote",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards)
+                .build()
+        );
+
+        // Test remote index routing table is generated with ExistingStoreRecoverySource if no routing table is present
+        {
+            final Index index = remoteMetadata.getIndex();
+            final ClusterState initialState = ClusterState.builder(ClusterState.EMPTY_STATE)
+                .metadata(Metadata.builder().put(remoteMetadata, false).build())
+                .build();
+            final ClusterState newState = updateRoutingTable(initialState);
+            IndexRoutingTable newRemoteIndexRoutingTable = newState.routingTable().index(remoteMetadata.getIndex());
+            assertTrue(newState.routingTable().hasIndex(index));
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.INDEX_CREATED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+
+        }
+
+        // Test remote index routing table is overridden if recovery source is not RemoteStoreRecoverySource
+        {
+            IndexRoutingTable.Builder remoteBuilderWithoutRemoteRecovery = new IndexRoutingTable.Builder(remoteMetadata.getIndex())
+                .initializeAsNew(remoteMetadata);
+            final Index index = remoteMetadata.getIndex();
+            final ClusterState initialState = ClusterState.builder(ClusterState.EMPTY_STATE)
+                .metadata(Metadata.builder().put(remoteMetadata, false).build())
+                .routingTable(new RoutingTable.Builder().add(remoteBuilderWithoutRemoteRecovery.build()).build())
+                .build();
+            assertTrue(initialState.routingTable().hasIndex(index));
+            final ClusterState newState = updateRoutingTable(initialState);
+            IndexRoutingTable newRemoteIndexRoutingTable = newState.routingTable().index(remoteMetadata.getIndex());
+            assertTrue(newState.routingTable().hasIndex(index));
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.INDEX_CREATED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+
+        }
+
+        // Test routing table update is skipped for a remote index
+        {
+            IndexRoutingTable.Builder remoteBuilderWithRemoteRecovery = new IndexRoutingTable.Builder(remoteMetadata.getIndex())
+                .initializeAsRemoteStoreRestore(
+                    remoteMetadata,
+                    new RecoverySource.RemoteStoreRecoverySource(
+                        UUIDs.randomBase64UUID(),
+                        remoteMetadata.getCreationVersion(),
+                        new IndexId(remoteMetadata.getIndex().getName(), remoteMetadata.getIndexUUID())
+                    ),
+                    new HashMap<>(),
+                    true
+                );
+            final Index index = remoteMetadata.getIndex();
+            final ClusterState initialState = ClusterState.builder(ClusterState.EMPTY_STATE)
+                .metadata(Metadata.builder().put(remoteMetadata, false).build())
+                .routingTable(new RoutingTable.Builder().add(remoteBuilderWithRemoteRecovery.build()).build())
+                .build();
+            assertTrue(initialState.routingTable().hasIndex(index));
+            final ClusterState newState = updateRoutingTable(initialState);
+            IndexRoutingTable newRemoteIndexRoutingTable = newState.routingTable().index(remoteMetadata.getIndex());
+            assertTrue(newState.routingTable().hasIndex(index));
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.EXISTING_INDEX_RESTORED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+
+        }
+
+        // Test reset routing table for 2 indices - one remote and one non remote.
+        // Routing table for non remote index should be updated and remote index routing table should remain intact
+        {
+            final IndexMetadata nonRemoteMetadata = createIndexMetadata(
+                "test-nonremote",
+                Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards).build()
+            );
+            IndexRoutingTable.Builder remoteBuilderWithRemoteRecovery = new IndexRoutingTable.Builder(remoteMetadata.getIndex())
+                .initializeAsRemoteStoreRestore(
+                    remoteMetadata,
+                    new RecoverySource.RemoteStoreRecoverySource(
+                        UUIDs.randomBase64UUID(),
+                        remoteMetadata.getCreationVersion(),
+                        new IndexId(remoteMetadata.getIndex().getName(), remoteMetadata.getIndexUUID())
+                    ),
+                    new HashMap<>(),
+                    true
+                );
+            IndexRoutingTable.Builder nonRemoteBuilderWithoutRemoteRecovery = new IndexRoutingTable.Builder(nonRemoteMetadata.getIndex())
+                .initializeAsNew(nonRemoteMetadata);
+            final ClusterState initialState = ClusterState.builder(ClusterState.EMPTY_STATE)
+                .metadata(Metadata.builder().put(remoteMetadata, false).build())
+                .metadata(Metadata.builder().put(nonRemoteMetadata, false).build())
+                .routingTable(
+                    new RoutingTable.Builder().add(remoteBuilderWithRemoteRecovery.build())
+                        .add(nonRemoteBuilderWithoutRemoteRecovery.build())
+                        .build()
+                )
+                .build();
+            assertTrue(initialState.routingTable().hasIndex(remoteMetadata.getIndex()));
+            assertTrue(initialState.routingTable().hasIndex(nonRemoteMetadata.getIndex()));
+            final ClusterState newState = updateRoutingTable(initialState);
+            assertTrue(newState.routingTable().hasIndex(remoteMetadata.getIndex()));
+            assertTrue(newState.routingTable().hasIndex(nonRemoteMetadata.getIndex()));
+            IndexRoutingTable newRemoteIndexRoutingTable = newState.routingTable().index(remoteMetadata.getIndex());
+            IndexRoutingTable newNonRemoteIndexRoutingTable = newState.routingTable().index(nonRemoteMetadata.getIndex());
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.EXISTING_INDEX_RESTORED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                0,
+                newNonRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.INDEX_CREATED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newNonRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                0,
+                newNonRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newNonRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+        }
+
+        // Test reset routing table for 2 indices, both remote backed but only once index has RemoteStoreRecoverySource.
+        // Routing table for only remote index without RemoteStoreRecoverySource should be updated
+        {
+            final IndexMetadata remoteWithoutRemoteRecoveryMetadata = createIndexMetadata(
+                "test-remote-without-recovery",
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, numOfShards)
+                    .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                    .build()
+            );
+            IndexRoutingTable.Builder remoteBuilderWithRemoteRecovery = new IndexRoutingTable.Builder(remoteMetadata.getIndex())
+                .initializeAsRemoteStoreRestore(
+                    remoteMetadata,
+                    new RecoverySource.RemoteStoreRecoverySource(
+                        UUIDs.randomBase64UUID(),
+                        remoteMetadata.getCreationVersion(),
+                        new IndexId(remoteMetadata.getIndex().getName(), remoteMetadata.getIndexUUID())
+                    ),
+                    new HashMap<>(),
+                    true
+                );
+            IndexRoutingTable.Builder remoteBuilderWithoutRemoteRecovery = new IndexRoutingTable.Builder(
+                remoteWithoutRemoteRecoveryMetadata.getIndex()
+            ).initializeAsNew(remoteWithoutRemoteRecoveryMetadata);
+            final ClusterState initialState = ClusterState.builder(ClusterState.EMPTY_STATE)
+                .metadata(Metadata.builder().put(remoteMetadata, false).build())
+                .metadata(Metadata.builder().put(remoteWithoutRemoteRecoveryMetadata, false).build())
+                .routingTable(
+                    new RoutingTable.Builder().add(remoteBuilderWithRemoteRecovery.build())
+                        .add(remoteBuilderWithoutRemoteRecovery.build())
+                        .build()
+                )
+                .build();
+            assertTrue(initialState.routingTable().hasIndex(remoteMetadata.getIndex()));
+            assertTrue(initialState.routingTable().hasIndex(remoteWithoutRemoteRecoveryMetadata.getIndex()));
+            final ClusterState newState = updateRoutingTable(initialState);
+            assertTrue(newState.routingTable().hasIndex(remoteMetadata.getIndex()));
+            assertTrue(newState.routingTable().hasIndex(remoteWithoutRemoteRecoveryMetadata.getIndex()));
+            IndexRoutingTable newRemoteIndexRoutingTable = newState.routingTable().index(remoteMetadata.getIndex());
+            IndexRoutingTable newRemoteWithoutRemoteRecoveryIndexRoutingTable = newState.routingTable()
+                .index(remoteWithoutRemoteRecoveryMetadata.getIndex());
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.EXISTING_INDEX_RESTORED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteWithoutRemoteRecoveryIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.INDEX_CREATED)
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteWithoutRemoteRecoveryIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.unassignedInfo().getReason().equals(UnassignedInfo.Reason.CLUSTER_RECOVERED)
+                )
+            );
+            assertEquals(
+                0,
+                newRemoteWithoutRemoteRecoveryIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.RemoteStoreRecoverySource
+                )
+            );
+            assertEquals(
+                numOfShards,
+                newRemoteWithoutRemoteRecoveryIndexRoutingTable.shardsMatchingPredicateCount(
+                    shardRouting -> shardRouting.recoverySource() instanceof RecoverySource.EmptyStoreRecoverySource
+                )
+            );
+        }
+    }
+
     public void testMixCurrentAndRecoveredState() {
         final ClusterState currentState = ClusterState.builder(ClusterState.EMPTY_STATE)
             .blocks(ClusterBlocks.builder().addGlobalBlock(STATE_NOT_RECOVERED_BLOCK).build())
diff --git a/server/src/test/java/org/opensearch/gateway/DanglingIndicesStateTests.java b/server/src/test/java/org/opensearch/gateway/DanglingIndicesStateTests.java
index 9534a53dbe77f..3f62abfc17037 100644
--- a/server/src/test/java/org/opensearch/gateway/DanglingIndicesStateTests.java
+++ b/server/src/test/java/org/opensearch/gateway/DanglingIndicesStateTests.java
@@ -37,16 +37,16 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -233,9 +233,8 @@ public void testDanglingIndicesNotImportedWhenIndexNameIsAlreadyUsed() throws Ex
             IndexMetadata existingIndex = IndexMetadata.builder("test_index").settings(existingSettings).build();
             metaStateService.writeIndex("test_write", existingIndex);
 
-            final ImmutableOpenMap<String, IndexMetadata> indices = ImmutableOpenMap.<String, IndexMetadata>builder()
-                .fPut(dangledIndex.getIndex().getName(), existingIndex)
-                .build();
+            final Map<String, IndexMetadata> indices = new HashMap<>();
+            indices.put(dangledIndex.getIndex().getName(), existingIndex);
             final Metadata metadata = Metadata.builder().indices(indices).build();
 
             // All dangling indices should be found...
diff --git a/server/src/test/java/org/opensearch/gateway/GatewayMetaStatePersistedStateTests.java b/server/src/test/java/org/opensearch/gateway/GatewayMetaStatePersistedStateTests.java
index 339b04f45c830..c7ed1cb732154 100644
--- a/server/src/test/java/org/opensearch/gateway/GatewayMetaStatePersistedStateTests.java
+++ b/server/src/test/java/org/opensearch/gateway/GatewayMetaStatePersistedStateTests.java
@@ -35,12 +35,16 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.CoordinationMetadata;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfigExclusion;
 import org.opensearch.cluster.coordination.CoordinationState;
+import org.opensearch.cluster.coordination.CoordinationState.PersistedState;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Manifest;
 import org.opensearch.cluster.metadata.Metadata;
@@ -48,18 +52,27 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.TestEnvironment;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.gateway.GatewayMetaState.RemotePersistedState;
+import org.opensearch.gateway.PersistedClusterStateService.Writer;
+import org.opensearch.gateway.remote.ClusterMetadataManifest;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.index.recovery.RemoteStoreRestoreService;
+import org.opensearch.index.recovery.RemoteStoreRestoreService.RemoteRestoreResult;
 import org.opensearch.node.Node;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -72,23 +85,41 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Supplier;
 
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import org.mockito.Mockito;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_INDEX_UUID;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteStoreClusterStateEnabled;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
 
 public class GatewayMetaStatePersistedStateTests extends OpenSearchTestCase {
+
     private NodeEnvironment nodeEnvironment;
     private ClusterName clusterName;
     private Settings settings;
     private DiscoveryNode localNode;
     private BigArrays bigArrays;
 
+    private MockGatewayMetaState gateway;
+
     @Override
     public void setUp() throws Exception {
         bigArrays = new MockBigArrays(new MockPageCacheRecycler(Settings.EMPTY), new NoneCircuitBreakerService());
@@ -108,14 +139,22 @@ public void setUp() throws Exception {
     @Override
     public void tearDown() throws Exception {
         nodeEnvironment.close();
+        IOUtils.close(gateway);
         super.tearDown();
     }
 
-    private CoordinationState.PersistedState newGatewayPersistedState() {
-        final MockGatewayMetaState gateway = new MockGatewayMetaState(localNode, bigArrays);
-        gateway.start(settings, nodeEnvironment, xContentRegistry());
+    private CoordinationState.PersistedState newGatewayPersistedState() throws IOException {
+        IOUtils.close(gateway);
+        gateway = new MockGatewayMetaState(localNode, bigArrays);
+        final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+        gateway.start(settings, nodeEnvironment, xContentRegistry(), persistedStateRegistry);
         final CoordinationState.PersistedState persistedState = gateway.getPersistedState();
         assertThat(persistedState, instanceOf(GatewayMetaState.LucenePersistedState.class));
+        assertThat(
+            persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL),
+            instanceOf(GatewayMetaState.LucenePersistedState.class)
+        );
+        assertThat(persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE), nullValue());
         return persistedState;
     }
 
@@ -405,14 +444,17 @@ public void testDataOnlyNodePersistence() throws Exception {
             );
             Settings settings = Settings.builder()
                 .put(ClusterName.CLUSTER_NAME_SETTING.getKey(), clusterName.value())
-                .put(nonMasterNode())
+                .put(nonClusterManagerNode())
                 .put(Node.NODE_NAME_SETTING.getKey(), "test")
                 .build();
             final MockGatewayMetaState gateway = new MockGatewayMetaState(localNode, bigArrays);
             cleanup.add(gateway);
             final TransportService transportService = mock(TransportService.class);
             TestThreadPool threadPool = new TestThreadPool("testMarkAcceptedConfigAsCommittedOnDataOnlyNode");
-            cleanup.add(() -> ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS));
+            cleanup.add(() -> {
+                ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
+                threadPool.shutdown();
+            });
             when(transportService.getThreadPool()).thenReturn(threadPool);
             ClusterService clusterService = mock(ClusterService.class);
             when(clusterService.getClusterSettings()).thenReturn(
@@ -425,6 +467,27 @@ public void testDataOnlyNodePersistence() throws Exception {
                 new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
                 () -> 0L
             );
+            Supplier<RemoteClusterStateService> remoteClusterStateServiceSupplier = () -> {
+                if (isRemoteStoreClusterStateEnabled(settings)) {
+                    return new RemoteClusterStateService(
+                        nodeEnvironment.nodeId(),
+                        () -> new RepositoriesService(
+                            settings,
+                            clusterService,
+                            transportService,
+                            Collections.emptyMap(),
+                            Collections.emptyMap(),
+                            transportService.getThreadPool()
+                        ),
+                        settings,
+                        new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                        () -> 0L,
+                        threadPool
+                    );
+                } else {
+                    return null;
+                }
+            };
             gateway.start(
                 settings,
                 transportService,
@@ -432,7 +495,10 @@ public void testDataOnlyNodePersistence() throws Exception {
                 new MetaStateService(nodeEnvironment, xContentRegistry()),
                 null,
                 null,
-                persistedClusterStateService
+                persistedClusterStateService,
+                remoteClusterStateServiceSupplier.get(),
+                new PersistedStateRegistry(),
+                null
             );
             final CoordinationState.PersistedState persistedState = gateway.getPersistedState();
             assertThat(persistedState, instanceOf(GatewayMetaState.AsyncLucenePersistedState.class));
@@ -647,6 +713,285 @@ Directory createDirectory(Path path) {
         }
     }
 
+    public void testRemotePersistedState() throws IOException {
+        final RemoteClusterStateService remoteClusterStateService = Mockito.mock(RemoteClusterStateService.class);
+        final ClusterMetadataManifest manifest = ClusterMetadataManifest.builder().clusterTerm(1L).stateVersion(5L).build();
+        final String previousClusterUUID = "prev-cluster-uuid";
+        Mockito.when(remoteClusterStateService.writeFullMetadata(Mockito.any(), Mockito.any())).thenReturn(manifest);
+
+        Mockito.when(remoteClusterStateService.writeIncrementalMetadata(Mockito.any(), Mockito.any(), Mockito.any())).thenReturn(manifest);
+        CoordinationState.PersistedState remotePersistedState = new RemotePersistedState(remoteClusterStateService, previousClusterUUID);
+
+        assertThat(remotePersistedState.getLastAcceptedState(), nullValue());
+        assertThat(remotePersistedState.getCurrentTerm(), equalTo(0L));
+
+        final long clusterTerm = randomNonNegativeLong();
+        final ClusterState clusterState = createClusterState(
+            randomNonNegativeLong(),
+            Metadata.builder().coordinationMetadata(CoordinationMetadata.builder().term(clusterTerm).build()).build()
+        );
+
+        remotePersistedState.setLastAcceptedState(clusterState);
+        Mockito.verify(remoteClusterStateService).writeFullMetadata(clusterState, previousClusterUUID);
+
+        assertThat(remotePersistedState.getLastAcceptedState(), equalTo(clusterState));
+        assertThat(remotePersistedState.getCurrentTerm(), equalTo(clusterTerm));
+
+        final ClusterState secondClusterState = createClusterState(
+            randomNonNegativeLong(),
+            Metadata.builder().coordinationMetadata(CoordinationMetadata.builder().term(clusterTerm).build()).build()
+        );
+
+        remotePersistedState.setLastAcceptedState(secondClusterState);
+        Mockito.verify(remoteClusterStateService, times(1)).writeFullMetadata(secondClusterState, previousClusterUUID);
+
+        assertThat(remotePersistedState.getLastAcceptedState(), equalTo(secondClusterState));
+        assertThat(remotePersistedState.getCurrentTerm(), equalTo(clusterTerm));
+
+        remotePersistedState.markLastAcceptedStateAsCommitted();
+        Mockito.verify(remoteClusterStateService, times(1)).markLastStateAsCommitted(Mockito.any(), Mockito.any());
+
+        assertThat(remotePersistedState.getLastAcceptedState(), equalTo(secondClusterState));
+        assertThat(remotePersistedState.getCurrentTerm(), equalTo(clusterTerm));
+        assertThat(remotePersistedState.getLastAcceptedState().metadata().clusterUUIDCommitted(), equalTo(false));
+
+        final ClusterState thirdClusterState = ClusterState.builder(secondClusterState)
+            .metadata(Metadata.builder(secondClusterState.getMetadata()).clusterUUID(randomAlphaOfLength(10)).build())
+            .build();
+        remotePersistedState.setLastAcceptedState(thirdClusterState);
+        remotePersistedState.markLastAcceptedStateAsCommitted();
+        assertThat(remotePersistedState.getLastAcceptedState().metadata().clusterUUIDCommitted(), equalTo(true));
+    }
+
+    public void testRemotePersistedStateExceptionOnFullStateUpload() throws IOException {
+        final RemoteClusterStateService remoteClusterStateService = Mockito.mock(RemoteClusterStateService.class);
+        final String previousClusterUUID = "prev-cluster-uuid";
+        Mockito.doThrow(IOException.class).when(remoteClusterStateService).writeFullMetadata(Mockito.any(), Mockito.any());
+
+        CoordinationState.PersistedState remotePersistedState = new RemotePersistedState(remoteClusterStateService, previousClusterUUID);
+
+        final long clusterTerm = randomNonNegativeLong();
+        final ClusterState clusterState = createClusterState(
+            randomNonNegativeLong(),
+            Metadata.builder().coordinationMetadata(CoordinationMetadata.builder().term(clusterTerm).build()).build()
+        );
+
+        assertThrows(OpenSearchException.class, () -> remotePersistedState.setLastAcceptedState(clusterState));
+    }
+
+    public void testGatewayForRemoteState() throws IOException {
+        MockGatewayMetaState gateway = null;
+        try {
+            RemoteClusterStateService remoteClusterStateService = mock(RemoteClusterStateService.class);
+            when(remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster")).thenReturn("test-cluster-uuid");
+            RemoteStoreRestoreService remoteStoreRestoreService = mock(RemoteStoreRestoreService.class);
+            when(remoteStoreRestoreService.restore(any(), any(), anyBoolean(), any())).thenReturn(
+                RemoteRestoreResult.build("test-cluster-uuid", null, ClusterState.EMPTY_STATE)
+            );
+            gateway = new MockGatewayMetaState(localNode, bigArrays, remoteClusterStateService, remoteStoreRestoreService);
+            final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+
+            String stateRepoTypeAttributeKey = String.format(
+                Locale.getDefault(),
+                "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+                "randomRepoName"
+            );
+            String stateRepoSettingsAttributeKeyPrefix = String.format(
+                Locale.getDefault(),
+                "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+                "randomRepoName"
+            );
+
+            Settings settings = Settings.builder()
+                .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, "randomRepoName")
+                .put(stateRepoTypeAttributeKey, FsRepository.TYPE)
+                .put(stateRepoSettingsAttributeKeyPrefix + "location", "randomRepoPath")
+                .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true)
+                .build();
+            gateway.start(settings, nodeEnvironment, xContentRegistry(), persistedStateRegistry);
+
+            final CoordinationState.PersistedState persistedState = gateway.getPersistedState();
+            assertThat(persistedState, instanceOf(GatewayMetaState.LucenePersistedState.class));
+            assertThat(
+                persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL),
+                instanceOf(GatewayMetaState.LucenePersistedState.class)
+            );
+            assertThat(
+                persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE),
+                instanceOf(GatewayMetaState.RemotePersistedState.class)
+            );
+        } finally {
+            IOUtils.close(gateway);
+        }
+    }
+
+    public void testGatewayForRemoteStateForInitialBootstrap() throws IOException {
+        MockGatewayMetaState gateway = null;
+        try {
+            final RemoteClusterStateService remoteClusterStateService = mock(RemoteClusterStateService.class);
+            when(remoteClusterStateService.getLastKnownUUIDFromRemote(clusterName.value())).thenReturn(ClusterState.UNKNOWN_UUID);
+
+            final RemoteStoreRestoreService remoteStoreRestoreService = mock(RemoteStoreRestoreService.class);
+            when(remoteStoreRestoreService.restore(any(), any(), anyBoolean(), any())).thenReturn(
+                RemoteRestoreResult.build("test-cluster-uuid", null, ClusterState.EMPTY_STATE)
+            );
+            final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+            gateway = newGatewayForRemoteState(
+                remoteClusterStateService,
+                remoteStoreRestoreService,
+                persistedStateRegistry,
+                ClusterState.EMPTY_STATE
+            );
+            final CoordinationState.PersistedState lucenePersistedState = gateway.getPersistedState();
+            PersistedState remotePersistedState = persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE);
+            verify(remoteClusterStateService).getLastKnownUUIDFromRemote(Mockito.any()); // change this
+            verifyNoInteractions(remoteStoreRestoreService);
+            assertThat(remotePersistedState.getLastAcceptedState(), nullValue());
+            assertThat(lucenePersistedState.getLastAcceptedState().metadata(), equalTo(ClusterState.EMPTY_STATE.metadata()));
+        } finally {
+            IOUtils.close(gateway);
+        }
+    }
+
+    public void testGatewayForRemoteStateForNodeReplacement() throws IOException {
+        MockGatewayMetaState gateway = null;
+        try {
+            final RemoteClusterStateService remoteClusterStateService = mock(RemoteClusterStateService.class);
+            when(remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster")).thenReturn("test-cluster-uuid");
+            final ClusterState previousState = createClusterState(
+                randomNonNegativeLong(),
+                Metadata.builder()
+                    .coordinationMetadata(CoordinationMetadata.builder().term(randomLong()).build())
+                    .put(
+                        IndexMetadata.builder("test-index1")
+                            .settings(settings(Version.CURRENT).put(SETTING_INDEX_UUID, randomAlphaOfLength(10)))
+                            .numberOfShards(5)
+                            .numberOfReplicas(1)
+                            .build(),
+                        false
+                    )
+                    .clusterUUID(randomAlphaOfLength(10))
+                    .build()
+            );
+            when(remoteClusterStateService.getLastKnownUUIDFromRemote(clusterName.value())).thenReturn(
+                previousState.metadata().clusterUUID()
+            );
+
+            final RemoteStoreRestoreService remoteStoreRestoreService = mock(RemoteStoreRestoreService.class);
+            when(remoteStoreRestoreService.restore(any(), any(), anyBoolean(), any())).thenReturn(
+                RemoteRestoreResult.build("test-cluster-uuid", null, previousState)
+            );
+            final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+            gateway = newGatewayForRemoteState(
+                remoteClusterStateService,
+                remoteStoreRestoreService,
+                persistedStateRegistry,
+                ClusterState.EMPTY_STATE
+            );
+            final CoordinationState.PersistedState lucenePersistedState = gateway.getPersistedState();
+            PersistedState remotePersistedState = persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE);
+            verify(remoteClusterStateService).getLastKnownUUIDFromRemote(Mockito.any());
+            verify(remoteStoreRestoreService).restore(any(), any(), anyBoolean(), any());
+            assertThat(remotePersistedState.getLastAcceptedState(), nullValue());
+            assertThat(lucenePersistedState.getLastAcceptedState().metadata(), equalTo(previousState.metadata()));
+        } finally {
+            IOUtils.close(gateway);
+        }
+    }
+
+    public void testGatewayForRemoteStateForNodeReboot() throws IOException {
+        MockGatewayMetaState gateway = null;
+        try {
+            final RemoteClusterStateService remoteClusterStateService = mock(RemoteClusterStateService.class);
+            final RemoteStoreRestoreService remoteStoreRestoreService = mock(RemoteStoreRestoreService.class);
+            final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+            final IndexMetadata indexMetadata = IndexMetadata.builder("test-index1")
+                .settings(settings(Version.CURRENT).put(SETTING_INDEX_UUID, randomAlphaOfLength(10)))
+                .numberOfShards(5)
+                .numberOfReplicas(1)
+                .build();
+            final ClusterState clusterState = createClusterState(
+                randomNonNegativeLong(),
+                Metadata.builder()
+                    .coordinationMetadata(CoordinationMetadata.builder().term(randomLong()).build())
+                    .put(indexMetadata, false)
+                    .clusterUUID(randomAlphaOfLength(10))
+                    .build()
+            );
+            gateway = newGatewayForRemoteState(remoteClusterStateService, remoteStoreRestoreService, persistedStateRegistry, clusterState);
+            final CoordinationState.PersistedState lucenePersistedState = gateway.getPersistedState();
+            PersistedState remotePersistedState = persistedStateRegistry.getPersistedState(PersistedStateType.REMOTE);
+            verifyNoInteractions(remoteClusterStateService);
+            verifyNoInteractions(remoteStoreRestoreService);
+            assertThat(remotePersistedState.getLastAcceptedState(), nullValue());
+            logger.info("lucene state metadata: {}", lucenePersistedState.getLastAcceptedState().toString());
+            logger.info("initial metadata: {}", clusterState.toString());
+            assertThat(lucenePersistedState.getLastAcceptedState().metadata().indices().size(), equalTo(1));
+            assertThat(lucenePersistedState.getLastAcceptedState().metadata().indices().get("test-index1"), equalTo(indexMetadata));
+        } finally {
+            IOUtils.close(gateway);
+        }
+    }
+
+    private MockGatewayMetaState newGatewayForRemoteState(
+        RemoteClusterStateService remoteClusterStateService,
+        RemoteStoreRestoreService remoteStoreRestoreService,
+        PersistedStateRegistry persistedStateRegistry,
+        ClusterState currentState
+    ) throws IOException {
+        MockGatewayMetaState gateway = new MockGatewayMetaState(localNode, bigArrays);
+        String randomRepoName = "randomRepoName";
+        String stateRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            randomRepoName
+        );
+        String stateRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            randomRepoName
+        );
+        Settings settingWithRemoteStateEnabled = Settings.builder()
+            .put(settings)
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, randomRepoName)
+            .put(stateRepoTypeAttributeKey, FsRepository.TYPE)
+            .put(stateRepoSettingsAttributeKeyPrefix + "location", "randomRepoPath")
+            .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true)
+            .build();
+        final TransportService transportService = mock(TransportService.class);
+        ClusterService clusterService = mock(ClusterService.class);
+        when(clusterService.getClusterSettings()).thenReturn(
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        final PersistedClusterStateService persistedClusterStateService = new PersistedClusterStateService(
+            nodeEnvironment,
+            xContentRegistry(),
+            getBigArrays(),
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            () -> 0L
+        );
+        if (!ClusterState.EMPTY_STATE.equals(currentState)) {
+            Writer writer = persistedClusterStateService.createWriter();
+            writer.writeFullStateAndCommit(currentState.term(), currentState);
+            writer.close();
+        }
+        final MetaStateService metaStateService = mock(MetaStateService.class);
+        when(metaStateService.loadFullState()).thenReturn(new Tuple<>(Manifest.empty(), ClusterState.EMPTY_STATE.metadata()));
+        gateway.start(
+            settingWithRemoteStateEnabled,
+            transportService,
+            clusterService,
+            metaStateService,
+            null,
+            null,
+            persistedClusterStateService,
+            remoteClusterStateService,
+            persistedStateRegistry,
+            remoteStoreRestoreService
+        );
+        return gateway;
+    }
+
     private static BigArrays getBigArrays() {
         return usually()
             ? BigArrays.NON_RECYCLING_INSTANCE
diff --git a/server/src/test/java/org/opensearch/gateway/GatewayMetaStateTests.java b/server/src/test/java/org/opensearch/gateway/GatewayMetaStateTests.java
index d1c177ae5964c..8358dc84b2e0e 100644
--- a/server/src/test/java/org/opensearch/gateway/GatewayMetaStateTests.java
+++ b/server/src/test/java/org/opensearch/gateway/GatewayMetaStateTests.java
@@ -114,9 +114,9 @@ public void testCustomMetadataNoChange() {
 
     public void testIndexTemplateValidation() {
         Metadata metadata = randomMetadata();
-        MetadataUpgrader metadataUpgrader = new MetadataUpgrader(
-            Collections.singletonList(customs -> { throw new IllegalStateException("template is incompatible"); })
-        );
+        MetadataUpgrader metadataUpgrader = new MetadataUpgrader(Collections.singletonList(customs -> {
+            throw new IllegalStateException("template is incompatible");
+        }));
         String message = expectThrows(
             IllegalStateException.class,
             () -> GatewayMetaState.upgradeMetadata(metadata, new MockMetadataIndexUpgradeService(false), metadataUpgrader)
diff --git a/server/src/test/java/org/opensearch/gateway/GatewayServiceTests.java b/server/src/test/java/org/opensearch/gateway/GatewayServiceTests.java
index 63792968b1c59..c448c4b07e03b 100644
--- a/server/src/test/java/org/opensearch/gateway/GatewayServiceTests.java
+++ b/server/src/test/java/org/opensearch/gateway/GatewayServiceTests.java
@@ -50,8 +50,8 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.gateway.TestGatewayAllocator;
@@ -61,7 +61,7 @@
 import java.util.HashSet;
 
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
-import static org.opensearch.test.NodeRoles.masterNode;
+import static org.opensearch.test.NodeRoles.clusterManagerNode;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.Matchers.hasItem;
 
@@ -129,13 +129,13 @@ public void testRecoverStateUpdateTask() throws Exception {
         GatewayService service = createService(Settings.builder());
         ClusterStateUpdateTask clusterStateUpdateTask = service.new RecoverStateUpdateTask();
         String nodeId = randomAlphaOfLength(10);
-        DiscoveryNode masterNode = DiscoveryNode.createLocal(
-            settings(Version.CURRENT).put(masterNode()).build(),
+        DiscoveryNode clusterManagerNode = DiscoveryNode.createLocal(
+            settings(Version.CURRENT).put(clusterManagerNode()).build(),
             new TransportAddress(TransportAddress.META_ADDRESS, 9300),
             nodeId
         );
         ClusterState stateWithBlock = ClusterState.builder(ClusterName.DEFAULT)
-            .nodes(DiscoveryNodes.builder().localNodeId(nodeId).masterNodeId(nodeId).add(masterNode).build())
+            .nodes(DiscoveryNodes.builder().localNodeId(nodeId).clusterManagerNodeId(nodeId).add(clusterManagerNode).build())
             .blocks(ClusterBlocks.builder().addGlobalBlock(STATE_NOT_RECOVERED_BLOCK).build())
             .build();
 
diff --git a/server/src/test/java/org/opensearch/gateway/IncrementalClusterStateWriterTests.java b/server/src/test/java/org/opensearch/gateway/IncrementalClusterStateWriterTests.java
index 21d5c897c4a7d..8e67c1cdf4fd0 100644
--- a/server/src/test/java/org/opensearch/gateway/IncrementalClusterStateWriterTests.java
+++ b/server/src/test/java/org/opensearch/gateway/IncrementalClusterStateWriterTests.java
@@ -53,14 +53,13 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.junit.annotations.TestLogging;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.nio.file.Path;
@@ -72,6 +71,8 @@
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.mockito.ArgumentCaptor;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
@@ -86,7 +87,7 @@
 
 public class IncrementalClusterStateWriterTests extends OpenSearchAllocationTestCase {
 
-    private ClusterState clusterStateWithUnassignedIndex(IndexMetadata indexMetadata, boolean masterEligible) {
+    private ClusterState clusterStateWithUnassignedIndex(IndexMetadata indexMetadata, boolean clusterManagerEligible) {
         Metadata metadata = Metadata.builder().put(indexMetadata, false).build();
 
         RoutingTable routingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
@@ -94,11 +95,11 @@ private ClusterState clusterStateWithUnassignedIndex(IndexMetadata indexMetadata
         return ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
             .metadata(metadata)
             .routingTable(routingTable)
-            .nodes(generateDiscoveryNodes(masterEligible))
+            .nodes(generateDiscoveryNodes(clusterManagerEligible))
             .build();
     }
 
-    private ClusterState clusterStateWithAssignedIndex(IndexMetadata indexMetadata, boolean masterEligible) {
+    private ClusterState clusterStateWithAssignedIndex(IndexMetadata indexMetadata, boolean clusterManagerEligible) {
         AllocationService strategy = createAllocationService(
             Settings.builder()
                 .put("cluster.routing.allocation.node_concurrent_recoveries", 100)
@@ -108,7 +109,7 @@ private ClusterState clusterStateWithAssignedIndex(IndexMetadata indexMetadata,
                 .build()
         );
 
-        ClusterState oldClusterState = clusterStateWithUnassignedIndex(indexMetadata, masterEligible);
+        ClusterState oldClusterState = clusterStateWithUnassignedIndex(indexMetadata, clusterManagerEligible);
         RoutingTable routingTable = strategy.reroute(oldClusterState, "reroute").routingTable();
 
         Metadata metadataNewClusterState = Metadata.builder().put(oldClusterState.metadata().index("test"), false).build();
@@ -120,8 +121,8 @@ private ClusterState clusterStateWithAssignedIndex(IndexMetadata indexMetadata,
             .build();
     }
 
-    private ClusterState clusterStateWithNonReplicatedClosedIndex(IndexMetadata indexMetadata, boolean masterEligible) {
-        ClusterState oldClusterState = clusterStateWithAssignedIndex(indexMetadata, masterEligible);
+    private ClusterState clusterStateWithNonReplicatedClosedIndex(IndexMetadata indexMetadata, boolean clusterManagerEligible) {
+        ClusterState oldClusterState = clusterStateWithAssignedIndex(indexMetadata, clusterManagerEligible);
 
         Metadata metadataNewClusterState = Metadata.builder()
             .put(
@@ -142,8 +143,12 @@ private ClusterState clusterStateWithNonReplicatedClosedIndex(IndexMetadata inde
             .build();
     }
 
-    private ClusterState clusterStateWithReplicatedClosedIndex(IndexMetadata indexMetadata, boolean masterEligible, boolean assigned) {
-        ClusterState oldClusterState = clusterStateWithAssignedIndex(indexMetadata, masterEligible);
+    private ClusterState clusterStateWithReplicatedClosedIndex(
+        IndexMetadata indexMetadata,
+        boolean clusterManagerEligible,
+        boolean assigned
+    ) {
+        ClusterState oldClusterState = clusterStateWithAssignedIndex(indexMetadata, clusterManagerEligible);
 
         Metadata metadataNewClusterState = Metadata.builder()
             .put(
@@ -178,20 +183,20 @@ private ClusterState clusterStateWithReplicatedClosedIndex(IndexMetadata indexMe
             .build();
     }
 
-    private DiscoveryNodes.Builder generateDiscoveryNodes(boolean masterEligible) {
+    private DiscoveryNodes.Builder generateDiscoveryNodes(boolean clusterManagerEligible) {
         Set<DiscoveryNodeRole> dataOnlyRoles = Collections.singleton(DiscoveryNodeRole.DATA_ROLE);
         return DiscoveryNodes.builder()
-            .add(newNode("node1", masterEligible ? MASTER_DATA_ROLES : dataOnlyRoles))
-            .add(newNode("master_node", MASTER_DATA_ROLES))
+            .add(newNode("node1", clusterManagerEligible ? CLUSTER_MANAGER_DATA_ROLES : dataOnlyRoles))
+            .add(newNode("cluster_manager_node", CLUSTER_MANAGER_DATA_ROLES))
             .localNodeId("node1")
-            .masterNodeId(masterEligible ? "node1" : "master_node");
+            .clusterManagerNodeId(clusterManagerEligible ? "node1" : "cluster_manager_node");
     }
 
     private IndexMetadata createIndexMetadata(String name) {
         return IndexMetadata.builder(name).settings(settings(Version.CURRENT)).numberOfShards(5).numberOfReplicas(2).build();
     }
 
-    public void testGetRelevantIndicesWithUnassignedShardsOnMasterEligibleNode() {
+    public void testGetRelevantIndicesWithUnassignedShardsOnClusterManagerEligibleNode() {
         IndexMetadata indexMetadata = createIndexMetadata("test");
         Set<Index> indices = IncrementalClusterStateWriter.getRelevantIndices(clusterStateWithUnassignedIndex(indexMetadata, true));
         assertThat(indices.size(), equalTo(0));
@@ -205,8 +210,10 @@ public void testGetRelevantIndicesWithUnassignedShardsOnDataOnlyNode() {
 
     public void testGetRelevantIndicesWithAssignedShards() {
         IndexMetadata indexMetadata = createIndexMetadata("test");
-        boolean masterEligible = randomBoolean();
-        Set<Index> indices = IncrementalClusterStateWriter.getRelevantIndices(clusterStateWithAssignedIndex(indexMetadata, masterEligible));
+        boolean clusterManagerEligible = randomBoolean();
+        Set<Index> indices = IncrementalClusterStateWriter.getRelevantIndices(
+            clusterStateWithAssignedIndex(indexMetadata, clusterManagerEligible)
+        );
         assertThat(indices.size(), equalTo(1));
     }
 
diff --git a/server/src/test/java/org/opensearch/gateway/MetaStateServiceTests.java b/server/src/test/java/org/opensearch/gateway/MetaStateServiceTests.java
index 7204f6001baa3..885280c13c209 100644
--- a/server/src/test/java/org/opensearch/gateway/MetaStateServiceTests.java
+++ b/server/src/test/java/org/opensearch/gateway/MetaStateServiceTests.java
@@ -38,8 +38,8 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/gateway/MetadataStateFormatTests.java b/server/src/test/java/org/opensearch/gateway/MetadataStateFormatTests.java
index fe7b1255cf716..53f370471c91f 100644
--- a/server/src/test/java/org/opensearch/gateway/MetadataStateFormatTests.java
+++ b/server/src/test/java/org/opensearch/gateway/MetadataStateFormatTests.java
@@ -37,15 +37,15 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
-import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.apache.lucene.store.NIOFSDirectory;
+import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/gateway/PersistedClusterStateServiceTests.java b/server/src/test/java/org/opensearch/gateway/PersistedClusterStateServiceTests.java
index d7b8712a46f66..9255b0086c073 100644
--- a/server/src/test/java/org/opensearch/gateway/PersistedClusterStateServiceTests.java
+++ b/server/src/test/java/org/opensearch/gateway/PersistedClusterStateServiceTests.java
@@ -56,15 +56,15 @@
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeMetadata;
 import org.opensearch.gateway.PersistedClusterStateService.Writer;
-import org.opensearch.index.Index;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 
 import java.io.IOError;
diff --git a/server/src/test/java/org/opensearch/gateway/PrimaryShardAllocatorTests.java b/server/src/test/java/org/opensearch/gateway/PrimaryShardAllocatorTests.java
index 4a1ecb9661687..c31ce60cb96a1 100644
--- a/server/src/test/java/org/opensearch/gateway/PrimaryShardAllocatorTests.java
+++ b/server/src/test/java/org/opensearch/gateway/PrimaryShardAllocatorTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.gateway;
 
+import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.index.CorruptIndexException;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterName;
@@ -57,15 +58,19 @@
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.env.Environment;
 import org.opensearch.env.ShardLockObtainFailedException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.codec.CodecService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
+import org.opensearch.test.IndexSettingsModule;
 import org.junit.Before;
 
 import java.util.Arrays;
@@ -205,6 +210,203 @@ public void testShardLockObtainFailedException() {
         assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
     }
 
+    /**
+     * Tests that replica with the highest primary term version will be selected as target
+     */
+    public void testPreferReplicaWithHighestPrimaryTerm() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId2,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, false, new ReplicationCheckpoint(shardId, 20, 101, 1, Codec.getDefault().getName()));
+        testAllocator.addData(node2, allocId2, false, new ReplicationCheckpoint(shardId, 22, 120, 2, Codec.getDefault().getName()));
+        testAllocator.addData(node3, allocId3, false, new ReplicationCheckpoint(shardId, 20, 120, 2, Codec.getDefault().getName()));
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node2.getId())
+        );
+        // Assert node2's allocation id is used
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId2)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
+    /**
+     * Tests that replica with highest primary ter version will be selected as target
+     */
+    public void testPreferReplicaWithNullReplicationCheckpoint() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId2,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, false, new ReplicationCheckpoint(shardId, 20, 101, 1, Codec.getDefault().getName()));
+        testAllocator.addData(node2, allocId2, false);
+        testAllocator.addData(node3, allocId3, false, new ReplicationCheckpoint(shardId, 40, 120, 2, Codec.getDefault().getName()));
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node3.getId())
+        );
+        // Assert node3's allocation id should be used as it has highest replication checkpoint
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId3)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
+    /**
+     * Tests that null ReplicationCheckpoint are ignored
+     */
+    public void testPreferReplicaWithAllNullReplicationCheckpoint() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId2,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, false, null, null);
+        testAllocator.addData(node2, allocId2, false, null, null);
+        testAllocator.addData(node3, allocId3, true, null, null);
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node3.getId())
+        );
+        // Assert node3's allocation id should be used as it was previous primary
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId3)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
+    /**
+     * Tests that replica with highest segment info version will be selected as target on equal primary terms
+     */
+    public void testPreferReplicaWithHighestSegmentInfoVersion() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId2,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, false, new ReplicationCheckpoint(shardId, 10, 101, 1, Codec.getDefault().getName()));
+        testAllocator.addData(node2, allocId2, false, new ReplicationCheckpoint(shardId, 20, 120, 3, Codec.getDefault().getName()));
+        testAllocator.addData(node3, allocId3, false, new ReplicationCheckpoint(shardId, 20, 120, 2, Codec.getDefault().getName()));
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node2.getId())
+        );
+        // Assert node2's allocation id is used
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId2)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
+    /**
+     * Tests that prefer allocation of replica at lower checkpoint but in sync set
+     */
+    public void testOutOfSyncHighestRepCheckpointIsIgnored() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, false, new ReplicationCheckpoint(shardId, 10, 101, 1, Codec.getDefault().getName()));
+        testAllocator.addData(node2, allocId2, false, new ReplicationCheckpoint(shardId, 20, 120, 2, Codec.getDefault().getName()));
+        testAllocator.addData(node3, allocId3, false, new ReplicationCheckpoint(shardId, 15, 120, 2, Codec.getDefault().getName()));
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node3.getId())
+        );
+        // Assert node3's allocation id is used
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId3)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
+    /**
+     * Tests that prefer allocation of older primary over replica with higher replication checkpoint
+     */
+    public void testPreferAllocatingPreviousPrimaryWithLowerRepCheckpoint() {
+        String allocId1 = randomAlphaOfLength(10);
+        String allocId2 = randomAlphaOfLength(10);
+        String allocId3 = randomAlphaOfLength(10);
+        final RoutingAllocation allocation = routingAllocationWithOnePrimaryNoReplicas(
+            yesAllocationDeciders(),
+            CLUSTER_RECOVERED,
+            allocId1,
+            allocId2,
+            allocId3
+        );
+        testAllocator.addData(node1, allocId1, true, new ReplicationCheckpoint(shardId, 10, 101, 1, Codec.getDefault().getName()));
+        testAllocator.addData(node2, allocId2, false, new ReplicationCheckpoint(shardId, 20, 120, 2, Codec.getDefault().getName()));
+        testAllocator.addData(node3, allocId3, false, new ReplicationCheckpoint(shardId, 15, 120, 2, Codec.getDefault().getName()));
+        allocateAllUnassigned(allocation);
+        assertThat(allocation.routingNodesChanged(), equalTo(true));
+        assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
+        assertThat(allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).size(), equalTo(1));
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).currentNodeId(),
+            equalTo(node1.getId())
+        );
+        // Assert node1's allocation id is used with highest replication checkpoint
+        assertThat(
+            allocation.routingNodes().shardsWithState(ShardRoutingState.INITIALIZING).get(0).allocationId().getId(),
+            equalTo(allocId1)
+        );
+        assertClusterHealthStatus(allocation, ClusterHealthStatus.YELLOW);
+    }
+
     /**
      * Tests that when one node returns a ShardLockObtainFailedException and another properly loads the store, it will
      * select the second node as target
@@ -219,7 +421,7 @@ public void testShardLockObtainFailedExceptionPreferOtherValidCopies() {
             allocId2
         );
         testAllocator.addData(node1, allocId1, randomBoolean(), new ShardLockObtainFailedException(shardId, "test"));
-        testAllocator.addData(node2, allocId2, randomBoolean(), null);
+        testAllocator.addData(node2, allocId2, randomBoolean());
         allocateAllUnassigned(allocation);
         assertThat(allocation.routingNodesChanged(), equalTo(true));
         assertThat(allocation.routingNodes().unassigned().ignored().isEmpty(), equalTo(true));
@@ -509,19 +711,12 @@ private RoutingAllocation getRestoreRoutingAllocation(AllocationDeciders allocat
             .routingTable(routingTable)
             .nodes(DiscoveryNodes.builder().add(node1).add(node2).add(node3))
             .build();
-        return new RoutingAllocation(
-            allocationDeciders,
-            new RoutingNodes(state, false),
-            state,
-            null,
-            new SnapshotShardSizeInfo(ImmutableOpenMap.of()) {
-                @Override
-                public Long getShardSize(ShardRouting shardRouting) {
-                    return shardSize;
-                }
-            },
-            System.nanoTime()
-        );
+        return new RoutingAllocation(allocationDeciders, new RoutingNodes(state, false), state, null, new SnapshotShardSizeInfo(Map.of()) {
+            @Override
+            public Long getShardSize(ShardRouting shardRouting) {
+                return shardSize;
+            }
+        }, System.nanoTime());
     }
 
     private RoutingAllocation routingAllocationWithOnePrimaryNoReplicas(
@@ -601,17 +796,58 @@ public TestAllocator clear() {
             return this;
         }
 
+        public TestAllocator addData(
+            DiscoveryNode node,
+            String allocationId,
+            boolean primary,
+            ReplicationCheckpoint replicationCheckpoint
+        ) {
+            return addData(node, allocationId, primary, replicationCheckpoint, null);
+        }
+
         public TestAllocator addData(DiscoveryNode node, String allocationId, boolean primary) {
-            return addData(node, allocationId, primary, null);
+            Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
+            IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", nodeSettings);
+            return addData(
+                node,
+                allocationId,
+                primary,
+                ReplicationCheckpoint.empty(shardId, new CodecService(null, indexSettings, null).codec("default").getName()),
+                null
+            );
         }
 
         public TestAllocator addData(DiscoveryNode node, String allocationId, boolean primary, @Nullable Exception storeException) {
+            Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
+            IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", nodeSettings);
+            return addData(
+                node,
+                allocationId,
+                primary,
+                ReplicationCheckpoint.empty(shardId, new CodecService(null, indexSettings, null).codec("default").getName()),
+                storeException
+            );
+        }
+
+        public TestAllocator addData(
+            DiscoveryNode node,
+            String allocationId,
+            boolean primary,
+            ReplicationCheckpoint replicationCheckpoint,
+            @Nullable Exception storeException
+        ) {
             if (data == null) {
                 data = new HashMap<>();
             }
             data.put(
                 node,
-                new TransportNodesListGatewayStartedShards.NodeGatewayStartedShards(node, allocationId, primary, storeException)
+                new TransportNodesListGatewayStartedShards.NodeGatewayStartedShards(
+                    node,
+                    allocationId,
+                    primary,
+                    replicationCheckpoint,
+                    storeException
+                )
             );
             return this;
         }
diff --git a/server/src/test/java/org/opensearch/gateway/PriorityComparatorTests.java b/server/src/test/java/org/opensearch/gateway/PriorityComparatorTests.java
index 9e5c698091dde..048579d767dae 100644
--- a/server/src/test/java/org/opensearch/gateway/PriorityComparatorTests.java
+++ b/server/src/test/java/org/opensearch/gateway/PriorityComparatorTests.java
@@ -39,7 +39,7 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
diff --git a/server/src/test/java/org/opensearch/gateway/ReplicaShardAllocatorTests.java b/server/src/test/java/org/opensearch/gateway/ReplicaShardAllocatorTests.java
index 36ac93524d6aa..3eeebd8cab6e4 100644
--- a/server/src/test/java/org/opensearch/gateway/ReplicaShardAllocatorTests.java
+++ b/server/src/test/java/org/opensearch/gateway/ReplicaShardAllocatorTests.java
@@ -33,9 +33,11 @@
 package org.opensearch.gateway;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterInfo;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -59,14 +61,13 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLease;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.snapshots.SnapshotShardSizeInfo;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/gateway/remote/ClusterMetadataManifestTests.java b/server/src/test/java/org/opensearch/gateway/remote/ClusterMetadataManifestTests.java
new file mode 100644
index 0000000000000..66426c2a880a3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/gateway/remote/ClusterMetadataManifestTests.java
@@ -0,0 +1,250 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gateway.remote;
+
+import org.opensearch.Version;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedIndexMetadata;
+import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class ClusterMetadataManifestTests extends OpenSearchTestCase {
+
+    public void testClusterMetadataManifestXContent() throws IOException {
+        UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "test-uuid", "/test/upload/path");
+        ClusterMetadataManifest originalManifest = new ClusterMetadataManifest(
+            1L,
+            1L,
+            "test-cluster-uuid",
+            "test-state-uuid",
+            Version.CURRENT,
+            "test-node-id",
+            false,
+            Collections.singletonList(uploadedIndexMetadata),
+            "prev-cluster-uuid",
+            true
+        );
+        final XContentBuilder builder = JsonXContent.contentBuilder();
+        builder.startObject();
+        originalManifest.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        builder.endObject();
+
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(builder))) {
+            final ClusterMetadataManifest fromXContentManifest = ClusterMetadataManifest.fromXContent(parser);
+            assertEquals(originalManifest, fromXContentManifest);
+        }
+    }
+
+    public void testClusterMetadataManifestSerializationEqualsHashCode() {
+        ClusterMetadataManifest initialManifest = new ClusterMetadataManifest(
+            1337L,
+            7L,
+            "HrYF3kP5SmSPWtKlWhnNSA",
+            "6By9p9G0Rv2MmFYJcPAOgA",
+            Version.CURRENT,
+            "B10RX1f5RJenMQvYccCgSQ",
+            true,
+            randomUploadedIndexMetadataList(),
+            "yfObdx8KSMKKrXf8UyHhM",
+            true
+        );
+        {  // Mutate Cluster Term
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.clusterTerm(1338L);
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate State Version
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.stateVersion(8L);
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate Cluster UUID
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.clusterUUID("efOkMiPbQZCUQQgtFWdbPw");
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate State UUID
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.stateUUID("efOkMiPbQZCUQQgtFWdbPw");
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate OpenSearch Version
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.opensearchVersion(Version.V_EMPTY);
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate Committed State
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.committed(false);
+                    return builder.build();
+                }
+            );
+        }
+        {  // Mutate Indices
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.indices(randomUploadedIndexMetadataList());
+                    return builder.build();
+                }
+            );
+        }
+        { // Mutate Previous cluster UUID
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.previousClusterUUID("vZX62DCQEOzGXlxXCrEu");
+                    return builder.build();
+                }
+            );
+
+        }
+        { // Mutate cluster uuid committed
+            EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+                initialManifest,
+                orig -> OpenSearchTestCase.copyWriteable(
+                    orig,
+                    new NamedWriteableRegistry(Collections.emptyList()),
+                    ClusterMetadataManifest::new
+                ),
+                manifest -> {
+                    ClusterMetadataManifest.Builder builder = ClusterMetadataManifest.builder(manifest);
+                    builder.clusterUUIDCommitted(false);
+                    return builder.build();
+                }
+            );
+        }
+    }
+
+    private List<UploadedIndexMetadata> randomUploadedIndexMetadataList() {
+        final int size = randomIntBetween(1, 10);
+        final List<UploadedIndexMetadata> uploadedIndexMetadataList = new ArrayList<>(size);
+        while (uploadedIndexMetadataList.size() < size) {
+            assertTrue(uploadedIndexMetadataList.add(randomUploadedIndexMetadata()));
+        }
+        return uploadedIndexMetadataList;
+    }
+
+    private UploadedIndexMetadata randomUploadedIndexMetadata() {
+        return new UploadedIndexMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomAlphaOfLength(10));
+    }
+
+    public void testUploadedIndexMetadataSerializationEqualsHashCode() {
+        UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "test-uuid", "/test/upload/path");
+        EqualsHashCodeTestUtils.checkEqualsAndHashCode(
+            uploadedIndexMetadata,
+            orig -> OpenSearchTestCase.copyWriteable(orig, new NamedWriteableRegistry(Collections.emptyList()), UploadedIndexMetadata::new),
+            metadata -> randomlyChangingUploadedIndexMetadata(uploadedIndexMetadata)
+        );
+    }
+
+    private UploadedIndexMetadata randomlyChangingUploadedIndexMetadata(UploadedIndexMetadata uploadedIndexMetadata) {
+        switch (randomInt(2)) {
+            case 0:
+                return new UploadedIndexMetadata(
+                    randomAlphaOfLength(10),
+                    uploadedIndexMetadata.getIndexUUID(),
+                    uploadedIndexMetadata.getUploadedFilename()
+                );
+            case 1:
+                return new UploadedIndexMetadata(
+                    uploadedIndexMetadata.getIndexName(),
+                    randomAlphaOfLength(10),
+                    uploadedIndexMetadata.getUploadedFilename()
+                );
+            case 2:
+                return new UploadedIndexMetadata(
+                    uploadedIndexMetadata.getIndexName(),
+                    uploadedIndexMetadata.getIndexUUID(),
+                    randomAlphaOfLength(10)
+                );
+        }
+        return uploadedIndexMetadata;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/gateway/remote/RemoteClusterStateServiceTests.java b/server/src/test/java/org/opensearch/gateway/remote/RemoteClusterStateServiceTests.java
new file mode 100644
index 0000000000000..6ecbc23f75bee
--- /dev/null
+++ b/server/src/test/java/org/opensearch/gateway/remote/RemoteClusterStateServiceTests.java
@@ -0,0 +1,873 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.gateway.remote;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.support.PlainBlobMetadata;
+import org.opensearch.common.blobstore.transfer.RemoteTransferContainer;
+import org.opensearch.common.compress.DeflateCompressor;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedIndexMetadata;
+import org.opensearch.repositories.FilterRepository;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.VersionUtils;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+
+import java.io.ByteArrayInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Supplier;
+
+import org.mockito.ArgumentCaptor;
+import org.mockito.ArgumentMatchers;
+
+import static org.opensearch.gateway.remote.RemoteClusterStateService.DELIMITER;
+import static org.opensearch.gateway.remote.RemoteClusterStateService.MANIFEST_FILE_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteClusterStateServiceTests extends OpenSearchTestCase {
+
+    private RemoteClusterStateService remoteClusterStateService;
+    private Supplier<RepositoriesService> repositoriesServiceSupplier;
+    private RepositoriesService repositoriesService;
+    private BlobStoreRepository blobStoreRepository;
+    private BlobStore blobStore;
+    private final ThreadPool threadPool = new TestThreadPool(getClass().getName());
+
+    @Before
+    public void setup() {
+        repositoriesServiceSupplier = mock(Supplier.class);
+        repositoriesService = mock(RepositoriesService.class);
+        when(repositoriesServiceSupplier.get()).thenReturn(repositoriesService);
+
+        String stateRepoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            "remote_store_repository"
+        );
+        String stateRepoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            "remote_store_repository"
+        );
+
+        Settings settings = Settings.builder()
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, "remote_store_repository")
+            .put(stateRepoTypeAttributeKey, FsRepository.TYPE)
+            .put(stateRepoSettingsAttributeKeyPrefix + "location", "randomRepoPath")
+            .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), true)
+            .build();
+
+        blobStoreRepository = mock(BlobStoreRepository.class);
+        blobStore = mock(BlobStore.class);
+        when(blobStoreRepository.blobStore()).thenReturn(blobStore);
+        when(repositoriesService.repository("remote_store_repository")).thenReturn(blobStoreRepository);
+        when(blobStoreRepository.getNamedXContentRegistry()).thenReturn(new NamedXContentRegistry(new ArrayList<>()));
+        remoteClusterStateService = new RemoteClusterStateService(
+            "test-node-id",
+            repositoriesServiceSupplier,
+            settings,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            () -> 0L,
+            threadPool
+        );
+    }
+
+    @After
+    public void teardown() throws Exception {
+        super.tearDown();
+        remoteClusterStateService.close();
+        threadPool.shutdown();
+    }
+
+    public void testFailWriteFullMetadataNonClusterManagerNode() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().build();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.writeFullMetadata(clusterState, randomAlphaOfLength(10));
+        Assert.assertThat(manifest, nullValue());
+    }
+
+    public void testFailInitializationWhenRemoteStateDisabled() {
+        final Settings settings = Settings.builder().build();
+        assertThrows(
+            AssertionError.class,
+            () -> new RemoteClusterStateService(
+                "test-node-id",
+                repositoriesServiceSupplier,
+                settings,
+                new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                () -> 0L,
+                threadPool
+            )
+        );
+    }
+
+    public void testFailInitializeWhenRepositoryNotSet() {
+        doThrow(new RepositoryMissingException("repository missing")).when(repositoriesService).repository("remote_store_repository");
+        assertThrows(RepositoryMissingException.class, () -> remoteClusterStateService.start());
+    }
+
+    public void testFailWriteFullMetadataWhenNotBlobRepository() {
+        final FilterRepository filterRepository = mock(FilterRepository.class);
+        when(repositoriesService.repository("remote_store_repository")).thenReturn(filterRepository);
+        assertThrows(AssertionError.class, () -> remoteClusterStateService.start());
+    }
+
+    public void testWriteFullMetadataSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        mockBlobStoreObjects();
+        remoteClusterStateService.start();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.writeFullMetadata(clusterState, "prev-cluster-uuid");
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        assertThat(manifest.getIndices().size(), is(1));
+        assertThat(manifest.getIndices().get(0).getIndexName(), is(uploadedIndexMetadata.getIndexName()));
+        assertThat(manifest.getIndices().get(0).getIndexUUID(), is(uploadedIndexMetadata.getIndexUUID()));
+        assertThat(manifest.getIndices().get(0).getUploadedFilename(), notNullValue());
+        assertThat(manifest.getClusterTerm(), is(expectedManifest.getClusterTerm()));
+        assertThat(manifest.getStateVersion(), is(expectedManifest.getStateVersion()));
+        assertThat(manifest.getClusterUUID(), is(expectedManifest.getClusterUUID()));
+        assertThat(manifest.getStateUUID(), is(expectedManifest.getStateUUID()));
+        assertThat(manifest.getPreviousClusterUUID(), is(expectedManifest.getPreviousClusterUUID()));
+    }
+
+    public void testWriteFullMetadataInParallelSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        AsyncMultiStreamBlobContainer container = (AsyncMultiStreamBlobContainer) mockBlobStoreObjects(AsyncMultiStreamBlobContainer.class);
+
+        ArgumentCaptor<ActionListener<Void>> actionListenerArgumentCaptor = ArgumentCaptor.forClass(ActionListener.class);
+        ArgumentCaptor<WriteContext> writeContextArgumentCaptor = ArgumentCaptor.forClass(WriteContext.class);
+
+        doAnswer((i) -> {
+            actionListenerArgumentCaptor.getValue().onResponse(null);
+            return null;
+        }).when(container).asyncBlobUpload(writeContextArgumentCaptor.capture(), actionListenerArgumentCaptor.capture());
+
+        remoteClusterStateService.start();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.writeFullMetadata(clusterState, "prev-cluster-uuid");
+
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        assertThat(manifest.getIndices().size(), is(1));
+        assertThat(manifest.getIndices().get(0).getIndexName(), is(uploadedIndexMetadata.getIndexName()));
+        assertThat(manifest.getIndices().get(0).getIndexUUID(), is(uploadedIndexMetadata.getIndexUUID()));
+        assertThat(manifest.getIndices().get(0).getUploadedFilename(), notNullValue());
+        assertThat(manifest.getClusterTerm(), is(expectedManifest.getClusterTerm()));
+        assertThat(manifest.getStateVersion(), is(expectedManifest.getStateVersion()));
+        assertThat(manifest.getClusterUUID(), is(expectedManifest.getClusterUUID()));
+        assertThat(manifest.getStateUUID(), is(expectedManifest.getStateUUID()));
+        assertThat(manifest.getPreviousClusterUUID(), is(expectedManifest.getPreviousClusterUUID()));
+
+        assertEquals(actionListenerArgumentCaptor.getAllValues().size(), 1);
+        assertEquals(writeContextArgumentCaptor.getAllValues().size(), 1);
+
+        WriteContext capturedWriteContext = writeContextArgumentCaptor.getValue();
+        byte[] writtenBytes = capturedWriteContext.getStreamProvider(Integer.MAX_VALUE).provideStream(0).getInputStream().readAllBytes();
+        IndexMetadata writtenIndexMetadata = RemoteClusterStateService.INDEX_METADATA_FORMAT.deserialize(
+            capturedWriteContext.getFileName(),
+            blobStoreRepository.getNamedXContentRegistry(),
+            new BytesArray(writtenBytes)
+        );
+
+        assertEquals(capturedWriteContext.getWritePriority(), WritePriority.HIGH);
+        assertEquals(writtenIndexMetadata.getNumberOfShards(), 1);
+        assertEquals(writtenIndexMetadata.getNumberOfReplicas(), 0);
+        assertEquals(writtenIndexMetadata.getIndex().getName(), "test-index");
+        assertEquals(writtenIndexMetadata.getIndex().getUUID(), "index-uuid");
+        long expectedChecksum = RemoteTransferContainer.checksumOfChecksum(new ByteArrayIndexInput("metadata-filename", writtenBytes), 8);
+        if (capturedWriteContext.doRemoteDataIntegrityCheck()) {
+            assertEquals(capturedWriteContext.getExpectedChecksum().longValue(), expectedChecksum);
+        } else {
+            assertEquals(capturedWriteContext.getExpectedChecksum(), null);
+        }
+
+    }
+
+    public void testWriteFullMetadataInParallelFailure() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        AsyncMultiStreamBlobContainer container = (AsyncMultiStreamBlobContainer) mockBlobStoreObjects(AsyncMultiStreamBlobContainer.class);
+
+        ArgumentCaptor<ActionListener<Void>> actionListenerArgumentCaptor = ArgumentCaptor.forClass(ActionListener.class);
+
+        doAnswer((i) -> {
+            actionListenerArgumentCaptor.getValue().onFailure(new RuntimeException("Cannot upload to remote"));
+            return null;
+        }).when(container).asyncBlobUpload(any(WriteContext.class), actionListenerArgumentCaptor.capture());
+
+        remoteClusterStateService.start();
+        assertThrows(
+            RemoteClusterStateService.IndexMetadataTransferException.class,
+            () -> remoteClusterStateService.writeFullMetadata(clusterState, randomAlphaOfLength(10))
+        );
+    }
+
+    public void testFailWriteIncrementalMetadataNonClusterManagerNode() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().build();
+        remoteClusterStateService.start();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.writeIncrementalMetadata(clusterState, clusterState, null);
+        Assert.assertThat(manifest, nullValue());
+    }
+
+    public void testFailWriteIncrementalMetadataWhenTermChanged() {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder().term(2L).build();
+        final ClusterState previousClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(Metadata.builder().coordinationMetadata(coordinationMetadata))
+            .build();
+        assertThrows(
+            AssertionError.class,
+            () -> remoteClusterStateService.writeIncrementalMetadata(previousClusterState, clusterState, null)
+        );
+    }
+
+    public void testWriteIncrementalMetadataSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        mockBlobStoreObjects();
+        final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder().term(1L).build();
+        final ClusterState previousClusterState = ClusterState.builder(ClusterName.DEFAULT)
+            .metadata(Metadata.builder().coordinationMetadata(coordinationMetadata))
+            .build();
+
+        final ClusterMetadataManifest previousManifest = ClusterMetadataManifest.builder().indices(Collections.emptyList()).build();
+
+        remoteClusterStateService.start();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.writeIncrementalMetadata(
+            previousClusterState,
+            clusterState,
+            previousManifest
+        );
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        final List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        assertThat(manifest.getIndices().size(), is(1));
+        assertThat(manifest.getIndices().get(0).getIndexName(), is(uploadedIndexMetadata.getIndexName()));
+        assertThat(manifest.getIndices().get(0).getIndexUUID(), is(uploadedIndexMetadata.getIndexUUID()));
+        assertThat(manifest.getIndices().get(0).getUploadedFilename(), notNullValue());
+        assertThat(manifest.getClusterTerm(), is(expectedManifest.getClusterTerm()));
+        assertThat(manifest.getStateVersion(), is(expectedManifest.getStateVersion()));
+        assertThat(manifest.getClusterUUID(), is(expectedManifest.getClusterUUID()));
+        assertThat(manifest.getStateUUID(), is(expectedManifest.getStateUUID()));
+    }
+
+    public void testReadLatestMetadataManifestFailedIOException() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+
+        BlobContainer blobContainer = mockBlobStoreObjects();
+        when(blobContainer.listBlobsByPrefixInSortedOrder("manifest" + DELIMITER, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC))
+            .thenThrow(IOException.class);
+
+        remoteClusterStateService.start();
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> remoteClusterStateService.getLatestClusterMetadataManifest(
+                clusterState.getClusterName().value(),
+                clusterState.metadata().clusterUUID()
+            )
+        );
+        assertEquals(e.getMessage(), "Error while fetching latest manifest file for remote cluster state");
+    }
+
+    public void testReadLatestMetadataManifestFailedNoManifestFileInRemote() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+
+        BlobContainer blobContainer = mockBlobStoreObjects();
+        when(blobContainer.listBlobsByPrefixInSortedOrder("manifest" + DELIMITER, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC))
+            .thenReturn(List.of());
+
+        remoteClusterStateService.start();
+        Optional<ClusterMetadataManifest> manifest = remoteClusterStateService.getLatestClusterMetadataManifest(
+            clusterState.getClusterName().value(),
+            clusterState.metadata().clusterUUID()
+        );
+        assertEquals(manifest, Optional.empty());
+    }
+
+    public void testReadLatestMetadataManifestFailedManifestFileRemoveAfterFetchInRemote() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+
+        BlobContainer blobContainer = mockBlobStoreObjects();
+        BlobMetadata blobMetadata = new PlainBlobMetadata("manifestFileName", 1);
+        when(blobContainer.listBlobsByPrefixInSortedOrder("manifest" + DELIMITER, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC))
+            .thenReturn(Arrays.asList(blobMetadata));
+        when(blobContainer.readBlob("manifestFileName")).thenThrow(FileNotFoundException.class);
+
+        remoteClusterStateService.start();
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> remoteClusterStateService.getLatestClusterMetadataManifest(
+                clusterState.getClusterName().value(),
+                clusterState.metadata().clusterUUID()
+            )
+        );
+        assertEquals(e.getMessage(), "Error while downloading cluster metadata - manifestFileName");
+    }
+
+    public void testReadLatestMetadataManifestSuccessButNoIndexMetadata() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(List.of())
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        BlobContainer blobContainer = mockBlobStoreObjects();
+        mockBlobContainer(blobContainer, expectedManifest, Map.of());
+
+        remoteClusterStateService.start();
+        assertEquals(
+            remoteClusterStateService.getLatestIndexMetadata(clusterState.getClusterName().value(), clusterState.metadata().clusterUUID())
+                .size(),
+            0
+        );
+    }
+
+    public void testReadLatestMetadataManifestSuccessButIndexMetadataFetchIOException() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        final List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        BlobContainer blobContainer = mockBlobStoreObjects();
+        mockBlobContainer(blobContainer, expectedManifest, Map.of());
+        when(blobContainer.readBlob(uploadedIndexMetadata.getUploadedFilename() + ".dat")).thenThrow(FileNotFoundException.class);
+
+        remoteClusterStateService.start();
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> remoteClusterStateService.getLatestIndexMetadata(
+                clusterState.getClusterName().value(),
+                clusterState.metadata().clusterUUID()
+            )
+        );
+        assertEquals(e.getMessage(), "Error while downloading IndexMetadata - " + uploadedIndexMetadata.getUploadedFilename());
+    }
+
+    public void testReadLatestMetadataManifestSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        final List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        mockBlobContainer(mockBlobStoreObjects(), expectedManifest, new HashMap<>());
+        remoteClusterStateService.start();
+        final ClusterMetadataManifest manifest = remoteClusterStateService.getLatestClusterMetadataManifest(
+            clusterState.getClusterName().value(),
+            clusterState.metadata().clusterUUID()
+        ).get();
+
+        assertThat(manifest.getIndices().size(), is(1));
+        assertThat(manifest.getIndices().get(0).getIndexName(), is(uploadedIndexMetadata.getIndexName()));
+        assertThat(manifest.getIndices().get(0).getIndexUUID(), is(uploadedIndexMetadata.getIndexUUID()));
+        assertThat(manifest.getIndices().get(0).getUploadedFilename(), notNullValue());
+        assertThat(manifest.getClusterTerm(), is(expectedManifest.getClusterTerm()));
+        assertThat(manifest.getStateVersion(), is(expectedManifest.getStateVersion()));
+        assertThat(manifest.getClusterUUID(), is(expectedManifest.getClusterUUID()));
+        assertThat(manifest.getStateUUID(), is(expectedManifest.getStateUUID()));
+    }
+
+    public void testReadLatestIndexMetadataSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        remoteClusterStateService.start();
+
+        final Index index = new Index("test-index", "index-uuid");
+        String fileName = "metadata-" + index.getUUID();
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata(index.getName(), index.getUUID(), fileName);
+        final Settings idxSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_INDEX_UUID, index.getUUID())
+            .build();
+        final IndexMetadata indexMetadata = new IndexMetadata.Builder(index.getName()).settings(idxSettings)
+            .numberOfShards(11)
+            .numberOfReplicas(10)
+            .build();
+
+        final List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        mockBlobContainer(mockBlobStoreObjects(), expectedManifest, Map.of(index.getUUID(), indexMetadata));
+
+        Map<String, IndexMetadata> indexMetadataMap = remoteClusterStateService.getLatestIndexMetadata(
+            clusterState.getClusterName().value(),
+            clusterState.metadata().clusterUUID()
+        );
+
+        assertEquals(indexMetadataMap.size(), 1);
+        assertEquals(indexMetadataMap.get(index.getUUID()).getIndex().getName(), index.getName());
+        assertEquals(indexMetadataMap.get(index.getUUID()).getNumberOfShards(), indexMetadata.getNumberOfShards());
+        assertEquals(indexMetadataMap.get(index.getUUID()).getNumberOfReplicas(), indexMetadata.getNumberOfReplicas());
+    }
+
+    public void testMarkLastStateAsCommittedSuccess() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        mockBlobStoreObjects();
+        remoteClusterStateService.start();
+        final UploadedIndexMetadata uploadedIndexMetadata = new UploadedIndexMetadata("test-index", "index-uuid", "metadata-filename");
+        List<UploadedIndexMetadata> indices = List.of(uploadedIndexMetadata);
+        final ClusterMetadataManifest previousManifest = ClusterMetadataManifest.builder().indices(indices).build();
+
+        final ClusterMetadataManifest manifest = remoteClusterStateService.markLastStateAsCommitted(clusterState, previousManifest);
+
+        final ClusterMetadataManifest expectedManifest = ClusterMetadataManifest.builder()
+            .indices(indices)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID("state-uuid")
+            .clusterUUID("cluster-uuid")
+            .nodeId("nodeA")
+            .previousClusterUUID("prev-cluster-uuid")
+            .build();
+
+        assertThat(manifest.getIndices().size(), is(1));
+        assertThat(manifest.getIndices().get(0).getIndexName(), is(uploadedIndexMetadata.getIndexName()));
+        assertThat(manifest.getIndices().get(0).getIndexUUID(), is(uploadedIndexMetadata.getIndexUUID()));
+        assertThat(manifest.getIndices().get(0).getUploadedFilename(), notNullValue());
+        assertThat(manifest.getClusterTerm(), is(expectedManifest.getClusterTerm()));
+        assertThat(manifest.getStateVersion(), is(expectedManifest.getStateVersion()));
+        assertThat(manifest.getClusterUUID(), is(expectedManifest.getClusterUUID()));
+        assertThat(manifest.getStateUUID(), is(expectedManifest.getStateUUID()));
+    }
+
+    public void testGetValidPreviousClusterUUID() throws IOException {
+        Map<String, String> clusterUUIDsPointers = Map.of(
+            "cluster-uuid1",
+            ClusterState.UNKNOWN_UUID,
+            "cluster-uuid2",
+            "cluster-uuid1",
+            "cluster-uuid3",
+            "cluster-uuid2"
+        );
+        mockObjectsForGettingPreviousClusterUUID(clusterUUIDsPointers);
+
+        remoteClusterStateService.start();
+        String previousClusterUUID = remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster");
+        assertThat(previousClusterUUID, equalTo("cluster-uuid3"));
+    }
+
+    public void testGetValidPreviousClusterUUIDForInvalidChain() throws IOException {
+        Map<String, String> clusterUUIDsPointers = Map.of(
+            "cluster-uuid2",
+            "cluster-uuid1",
+            "cluster-uuid3",
+            "cluster-uuid2",
+            "cluster-uuid5",
+            "cluster-uuid4"
+        );
+        mockObjectsForGettingPreviousClusterUUID(clusterUUIDsPointers);
+
+        remoteClusterStateService.start();
+        assertThrows(IllegalStateException.class, () -> remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster"));
+    }
+
+    public void testGetValidPreviousClusterUUIDWithMultipleChains() throws IOException {
+        Map<String, String> clusterUUIDsPointers = Map.of(
+            "cluster-uuid2",
+            "cluster-uuid1",
+            "cluster-uuid1",
+            ClusterState.UNKNOWN_UUID,
+            "cluster-uuid3",
+            "cluster-uuid1"
+        );
+        mockObjectsForGettingPreviousClusterUUID(clusterUUIDsPointers);
+
+        remoteClusterStateService.start();
+        String previousClusterUUID = remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster");
+        assertThat(previousClusterUUID, equalTo("cluster-uuid3"));
+    }
+
+    public void testGetValidPreviousClusterUUIDWithInvalidMultipleChains() throws IOException {
+        Map<String, String> clusterUUIDsPointers = Map.of(
+            "cluster-uuid1",
+            ClusterState.UNKNOWN_UUID,
+            "cluster-uuid2",
+            "cluster-uuid1",
+            "cluster-uuid3",
+            ClusterState.UNKNOWN_UUID
+        );
+        mockObjectsForGettingPreviousClusterUUID(clusterUUIDsPointers);
+
+        remoteClusterStateService.start();
+        assertThrows(IllegalStateException.class, () -> remoteClusterStateService.getLastKnownUUIDFromRemote("test-cluster"));
+    }
+
+    public void testDeleteStaleClusterUUIDs() throws IOException {
+        final ClusterState clusterState = generateClusterStateWithOneIndex().nodes(nodesWithLocalNodeClusterManager()).build();
+        ClusterMetadataManifest clusterMetadataManifest = ClusterMetadataManifest.builder()
+            .indices(List.of())
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID(randomAlphaOfLength(10))
+            .clusterUUID("cluster-uuid1")
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID(ClusterState.UNKNOWN_UUID)
+            .committed(true)
+            .build();
+
+        BlobPath blobPath = new BlobPath().add("random-path");
+        when((blobStoreRepository.basePath())).thenReturn(blobPath);
+        BlobContainer uuidContainerContainer = mock(BlobContainer.class);
+        BlobContainer manifest2Container = mock(BlobContainer.class);
+        BlobContainer manifest3Container = mock(BlobContainer.class);
+        when(blobStore.blobContainer(any())).then(invocation -> {
+            BlobPath blobPath1 = invocation.getArgument(0);
+            if (blobPath1.buildAsString().endsWith("cluster-state/")) {
+                return uuidContainerContainer;
+            } else if (blobPath1.buildAsString().contains("cluster-state/cluster-uuid2/")) {
+                return manifest2Container;
+            } else if (blobPath1.buildAsString().contains("cluster-state/cluster-uuid3/")) {
+                return manifest3Container;
+            } else {
+                throw new IllegalArgumentException("Unexpected blob path " + blobPath1);
+            }
+        });
+        Map<String, BlobContainer> blobMetadataMap = Map.of(
+            "cluster-uuid1",
+            mock(BlobContainer.class),
+            "cluster-uuid2",
+            mock(BlobContainer.class),
+            "cluster-uuid3",
+            mock(BlobContainer.class)
+        );
+        when(uuidContainerContainer.children()).thenReturn(blobMetadataMap);
+        when(
+            manifest2Container.listBlobsByPrefixInSortedOrder(
+                MANIFEST_FILE_PREFIX + DELIMITER,
+                Integer.MAX_VALUE,
+                BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC
+            )
+        ).thenReturn(List.of(new PlainBlobMetadata("mainfest2", 1L)));
+        when(
+            manifest3Container.listBlobsByPrefixInSortedOrder(
+                MANIFEST_FILE_PREFIX + DELIMITER,
+                Integer.MAX_VALUE,
+                BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC
+            )
+        ).thenReturn(List.of(new PlainBlobMetadata("mainfest3", 1L)));
+        remoteClusterStateService.start();
+        remoteClusterStateService.deleteStaleClusterUUIDs(clusterState, clusterMetadataManifest);
+        try {
+            assertBusy(() -> {
+                verify(manifest2Container, times(1)).delete();
+                verify(manifest3Container, times(1)).delete();
+            });
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void mockObjectsForGettingPreviousClusterUUID(Map<String, String> clusterUUIDsPointers) throws IOException {
+        final BlobPath blobPath = mock(BlobPath.class);
+        when((blobStoreRepository.basePath())).thenReturn(blobPath);
+        when(blobPath.add(anyString())).thenReturn(blobPath);
+        when(blobPath.buildAsString()).thenReturn("/blob/path/");
+        BlobContainer blobContainer1 = mock(BlobContainer.class);
+        BlobContainer blobContainer2 = mock(BlobContainer.class);
+        BlobContainer blobContainer3 = mock(BlobContainer.class);
+        BlobContainer uuidBlobContainer = mock(BlobContainer.class);
+        when(blobContainer1.path()).thenReturn(blobPath);
+        when(blobContainer2.path()).thenReturn(blobPath);
+        when(blobContainer3.path()).thenReturn(blobPath);
+
+        mockBlobContainerForClusterUUIDs(uuidBlobContainer, clusterUUIDsPointers.keySet());
+        List<UploadedIndexMetadata> uploadedIndexMetadataList1 = List.of(
+            new UploadedIndexMetadata("index1", "index-uuid1", "key1"),
+            new UploadedIndexMetadata("index2", "index-uuid2", "key2")
+        );
+        final ClusterMetadataManifest clusterManifest1 = generateClusterMetadataManifest(
+            "cluster-uuid1",
+            clusterUUIDsPointers.get("cluster-uuid1"),
+            randomAlphaOfLength(10),
+            uploadedIndexMetadataList1
+        );
+        Settings indexSettings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build();
+        IndexMetadata indexMetadata1 = IndexMetadata.builder("index1")
+            .settings(indexSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        IndexMetadata indexMetadata2 = IndexMetadata.builder("index2")
+            .settings(indexSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        Map<String, IndexMetadata> indexMetadataMap1 = Map.of("index-uuid1", indexMetadata1, "index-uuid2", indexMetadata2);
+        mockBlobContainer(blobContainer1, clusterManifest1, indexMetadataMap1);
+
+        List<UploadedIndexMetadata> uploadedIndexMetadataList2 = List.of(
+            new UploadedIndexMetadata("index1", "index-uuid1", "key1"),
+            new UploadedIndexMetadata("index2", "index-uuid2", "key2")
+        );
+        final ClusterMetadataManifest clusterManifest2 = generateClusterMetadataManifest(
+            "cluster-uuid2",
+            clusterUUIDsPointers.get("cluster-uuid2"),
+            randomAlphaOfLength(10),
+            uploadedIndexMetadataList2
+        );
+        IndexMetadata indexMetadata3 = IndexMetadata.builder("index1")
+            .settings(indexSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        IndexMetadata indexMetadata4 = IndexMetadata.builder("index2")
+            .settings(indexSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        Map<String, IndexMetadata> indexMetadataMap2 = Map.of("index-uuid1", indexMetadata3, "index-uuid2", indexMetadata4);
+        mockBlobContainer(blobContainer2, clusterManifest2, indexMetadataMap2);
+
+        List<UploadedIndexMetadata> uploadedIndexMetadataList3 = List.of(new UploadedIndexMetadata("index1", "index-uuid1", "key1"));
+        final ClusterMetadataManifest clusterManifest3 = generateClusterMetadataManifest(
+            "cluster-uuid3",
+            clusterUUIDsPointers.get("cluster-uuid3"),
+            randomAlphaOfLength(10),
+            uploadedIndexMetadataList3
+        );
+        IndexMetadata indexMetadata5 = IndexMetadata.builder("index1")
+            .settings(indexSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        Map<String, IndexMetadata> indexMetadataMap3 = Map.of("index-uuid1", indexMetadata5);
+        mockBlobContainer(blobContainer3, clusterManifest3, indexMetadataMap3);
+
+        when(blobStore.blobContainer(ArgumentMatchers.any())).thenReturn(
+            uuidBlobContainer,
+            blobContainer1,
+            blobContainer1,
+            blobContainer3,
+            blobContainer3,
+            blobContainer2,
+            blobContainer2,
+            blobContainer1,
+            blobContainer2,
+            blobContainer1,
+            blobContainer2
+        );
+        when(blobStoreRepository.getCompressor()).thenReturn(new DeflateCompressor());
+    }
+
+    private ClusterMetadataManifest generateClusterMetadataManifest(
+        String clusterUUID,
+        String previousClusterUUID,
+        String stateUUID,
+        List<UploadedIndexMetadata> uploadedIndexMetadata
+    ) {
+        return ClusterMetadataManifest.builder()
+            .indices(uploadedIndexMetadata)
+            .clusterTerm(1L)
+            .stateVersion(1L)
+            .stateUUID(stateUUID)
+            .clusterUUID(clusterUUID)
+            .nodeId("nodeA")
+            .opensearchVersion(VersionUtils.randomOpenSearchVersion(random()))
+            .previousClusterUUID(previousClusterUUID)
+            .committed(true)
+            .clusterUUIDCommitted(true)
+            .build();
+    }
+
+    private BlobContainer mockBlobStoreObjects() {
+        return mockBlobStoreObjects(BlobContainer.class);
+    }
+
+    private BlobContainer mockBlobStoreObjects(Class<? extends BlobContainer> blobContainerClazz) {
+        final BlobPath blobPath = mock(BlobPath.class);
+        when((blobStoreRepository.basePath())).thenReturn(blobPath);
+        when(blobPath.add(anyString())).thenReturn(blobPath);
+        when(blobPath.buildAsString()).thenReturn("/blob/path/");
+        final BlobContainer blobContainer = mock(blobContainerClazz);
+        when(blobContainer.path()).thenReturn(blobPath);
+        when(blobStore.blobContainer(any())).thenReturn(blobContainer);
+        when(blobStoreRepository.getCompressor()).thenReturn(new DeflateCompressor());
+        return blobContainer;
+    }
+
+    private void mockBlobContainerForClusterUUIDs(BlobContainer blobContainer, Set<String> clusterUUIDs) throws IOException {
+        Map<String, BlobContainer> blobContainerMap = new HashMap<>();
+        for (String clusterUUID : clusterUUIDs) {
+            blobContainerMap.put(clusterUUID, mockBlobStoreObjects());
+        }
+        when(blobContainer.children()).thenReturn(blobContainerMap);
+    }
+
+    private void mockBlobContainer(
+        BlobContainer blobContainer,
+        ClusterMetadataManifest clusterMetadataManifest,
+        Map<String, IndexMetadata> indexMetadataMap
+    ) throws IOException {
+        BlobMetadata blobMetadata = new PlainBlobMetadata("manifestFileName", 1);
+        when(blobContainer.listBlobsByPrefixInSortedOrder("manifest" + DELIMITER, 1, BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC))
+            .thenReturn(Arrays.asList(blobMetadata));
+
+        BytesReference bytes = RemoteClusterStateService.CLUSTER_METADATA_MANIFEST_FORMAT.serialize(
+            clusterMetadataManifest,
+            "manifestFileName",
+            blobStoreRepository.getCompressor()
+        );
+        when(blobContainer.readBlob("manifestFileName")).thenReturn(new ByteArrayInputStream(bytes.streamInput().readAllBytes()));
+
+        clusterMetadataManifest.getIndices().forEach(uploadedIndexMetadata -> {
+            try {
+                IndexMetadata indexMetadata = indexMetadataMap.get(uploadedIndexMetadata.getIndexUUID());
+                if (indexMetadata == null) {
+                    return;
+                }
+                String fileName = uploadedIndexMetadata.getUploadedFilename();
+                BytesReference bytesIndexMetadata = RemoteClusterStateService.INDEX_METADATA_FORMAT.serialize(
+                    indexMetadata,
+                    fileName,
+                    blobStoreRepository.getCompressor()
+                );
+                when(blobContainer.readBlob(fileName + ".dat")).thenReturn(
+                    new ByteArrayInputStream(bytesIndexMetadata.streamInput().readAllBytes())
+                );
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+    }
+
+    private static ClusterState.Builder generateClusterStateWithOneIndex() {
+        final Index index = new Index("test-index", "index-uuid");
+        final Settings idxSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_INDEX_UUID, index.getUUID())
+            .build();
+        final IndexMetadata indexMetadata = new IndexMetadata.Builder(index.getName()).settings(idxSettings)
+            .numberOfShards(1)
+            .numberOfReplicas(0)
+            .build();
+        final CoordinationMetadata coordinationMetadata = CoordinationMetadata.builder().term(1L).build();
+
+        return ClusterState.builder(ClusterName.DEFAULT)
+            .version(1L)
+            .stateUUID("state-uuid")
+            .metadata(
+                Metadata.builder().put(indexMetadata, true).clusterUUID("cluster-uuid").coordinationMetadata(coordinationMetadata).build()
+            );
+    }
+
+    private static DiscoveryNodes nodesWithLocalNodeClusterManager() {
+        return DiscoveryNodes.builder().clusterManagerNodeId("cluster-manager-id").localNodeId("cluster-manager-id").build();
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/http/AbstractHttpServerTransportTests.java b/server/src/test/java/org/opensearch/http/AbstractHttpServerTransportTests.java
index d704096e2d9ca..c34f13041cb11 100644
--- a/server/src/test/java/org/opensearch/http/AbstractHttpServerTransportTests.java
+++ b/server/src/test/java/org/opensearch/http/AbstractHttpServerTransportTests.java
@@ -35,25 +35,26 @@
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.Task;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.threadpool.TestThreadPool;
@@ -173,7 +174,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 threadPool,
                 xContentRegistry(),
                 dispatcher,
-                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+                NoopTracer.INSTANCE
             ) {
 
                 @Override
@@ -238,7 +240,8 @@ public void dispatchBadRequest(RestChannel channel, ThreadContext threadContext,
                         channel.sendResponse(emptyResponse(RestStatus.BAD_REQUEST));
                     }
                 },
-                clusterSettings
+                clusterSettings,
+                NoopTracer.INSTANCE
             ) {
                 @Override
                 protected HttpServerChannel bind(InetSocketAddress hostAddress) {
diff --git a/server/src/test/java/org/opensearch/http/CorsHandlerTests.java b/server/src/test/java/org/opensearch/http/CorsHandlerTests.java
index 08464db73fd78..7dbb55c29d66c 100644
--- a/server/src/test/java/org/opensearch/http/CorsHandlerTests.java
+++ b/server/src/test/java/org/opensearch/http/CorsHandlerTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
@@ -50,7 +50,7 @@
 import java.util.regex.PatternSyntaxException;
 import java.util.stream.Collectors;
 
-import static org.opensearch.common.Strings.collectionToDelimitedString;
+import static org.opensearch.core.common.Strings.collectionToDelimitedString;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ALLOW_CREDENTIALS;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ALLOW_HEADERS;
 import static org.opensearch.http.HttpTransportSettings.SETTING_CORS_ALLOW_METHODS;
diff --git a/server/src/test/java/org/opensearch/http/DefaultRestChannelTests.java b/server/src/test/java/org/opensearch/http/DefaultRestChannelTests.java
index e7a5de91271a2..017af2581692f 100644
--- a/server/src/test/java/org/opensearch/http/DefaultRestChannelTests.java
+++ b/server/src/test/java/org/opensearch/http/DefaultRestChannelTests.java
@@ -32,33 +32,32 @@
 
 package org.opensearch.http;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.tasks.Task;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.After;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.nio.channels.ClosedChannelException;
@@ -68,6 +67,8 @@
 import java.util.Map;
 import java.util.Objects;
 
+import org.mockito.ArgumentCaptor;
+
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
diff --git a/server/src/test/java/org/opensearch/http/HttpInfoTests.java b/server/src/test/java/org/opensearch/http/HttpInfoTests.java
index 8c03a5b43e6e2..8c5710af39661 100644
--- a/server/src/test/java/org/opensearch/http/HttpInfoTests.java
+++ b/server/src/test/java/org/opensearch/http/HttpInfoTests.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.http;
 
-import java.io.IOException;
-import java.net.InetAddress;
-import java.util.Map;
 import org.opensearch.common.network.NetworkAddress;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.Map;
+
 public class HttpInfoTests extends OpenSearchTestCase {
 
     public void testCorrectlyDisplayPublishedCname() throws Exception {
diff --git a/server/src/test/java/org/opensearch/http/TestHttpRequest.java b/server/src/test/java/org/opensearch/http/TestHttpRequest.java
index 3b604ba03aa6f..0a40cd858eb82 100644
--- a/server/src/test/java/org/opensearch/http/TestHttpRequest.java
+++ b/server/src/test/java/org/opensearch/http/TestHttpRequest.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.util.Arrays;
 import java.util.HashMap;
diff --git a/server/src/test/java/org/opensearch/http/TestHttpResponse.java b/server/src/test/java/org/opensearch/http/TestHttpResponse.java
index 6dc82cb310cc6..9afe8591badc6 100644
--- a/server/src/test/java/org/opensearch/http/TestHttpResponse.java
+++ b/server/src/test/java/org/opensearch/http/TestHttpResponse.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.http;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
 
 import java.util.ArrayList;
 import java.util.HashMap;
diff --git a/server/src/test/java/org/opensearch/index/IndexModuleTests.java b/server/src/test/java/org/opensearch/index/IndexModuleTests.java
index daa9186dfd8c0..e77a1f02b86e0 100644
--- a/server/src/test/java/org/opensearch/index/IndexModuleTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexModuleTests.java
@@ -33,7 +33,6 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
-import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FieldInvertState;
 import org.apache.lucene.index.Term;
@@ -44,7 +43,7 @@
 import org.apache.lucene.search.similarities.BM25Similarity;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.SetOnce.AlreadySetException;
+import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
@@ -54,15 +53,22 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.breaker.CircuitBreaker;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.SetOnce.AlreadySetException;
+import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLock;
@@ -80,32 +86,39 @@
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.mapper.Uid;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexingOperationListener;
 import org.opensearch.index.shard.SearchOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.similarity.NonNegativeScoresSimilarity;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.index.store.FsDirectoryFactory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
+import org.opensearch.index.translog.InternalTranslogFactory;
+import org.opensearch.index.translog.RemoteBlobStoreInternalTranslogFactory;
+import org.opensearch.index.translog.TranslogFactory;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.IndicesQueryCache;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.plugins.IndexStorePlugin;
+import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.internal.ReaderContext;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.ClusterServiceUtils;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.engine.MockEngineFactory;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.Transport;
+import org.opensearch.transport.TransportService;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -115,6 +128,7 @@
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BiFunction;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
@@ -151,6 +165,7 @@ public void addPendingDelete(ShardId shardId, IndexSettings indexSettings) {}
     private BigArrays bigArrays;
     private ScriptService scriptService;
     private ClusterService clusterService;
+    private RepositoriesService repositoriesService;
 
     @Override
     public void setUp() throws Exception {
@@ -183,6 +198,25 @@ public void setUp() throws Exception {
         clusterService = ClusterServiceUtils.createClusterService(threadPool);
         nodeEnvironment = new NodeEnvironment(settings, environment);
         mapperRegistry = new IndicesModule(Collections.emptyList()).getMapperRegistry();
+        TransportService transportService = new TransportService(
+            settings,
+            mock(Transport.class),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> DiscoveryNode.createLocal(settings, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        repositoriesService = new RepositoriesService(
+            settings,
+            clusterService,
+            transportService,
+            Collections.emptyMap(),
+            Collections.emptyMap(),
+            threadPool
+        );
+
     }
 
     @Override
@@ -193,6 +227,19 @@ public void tearDown() throws Exception {
     }
 
     private IndexService newIndexService(IndexModule module) throws IOException {
+        final SetOnce<RepositoriesService> repositoriesServiceReference = new SetOnce<>();
+        repositoriesServiceReference.set(repositoriesService);
+        BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier = (indexSettings, shardRouting) -> {
+            if (indexSettings.isRemoteTranslogStoreEnabled() && shardRouting.primary()) {
+                return new RemoteBlobStoreInternalTranslogFactory(
+                    repositoriesServiceReference::get,
+                    threadPool,
+                    indexSettings.getRemoteStoreTranslogRepository(),
+                    new RemoteTranslogTransferTracker(shardRouting.shardId(), 10)
+                );
+            }
+            return new InternalTranslogFactory();
+        };
         return module.newIndexService(
             CREATE_INDEX,
             nodeEnvironment,
@@ -209,7 +256,11 @@ private IndexService newIndexService(IndexModule module) throws IOException {
             new IndicesFieldDataCache(settings, listener),
             writableRegistry(),
             () -> false,
-            null
+            null,
+            new RemoteSegmentStoreDirectoryFactory(() -> repositoriesService, threadPool, DefaultRecoverySettings.INSTANCE),
+            translogFactorySupplier,
+            () -> IndexSettings.DEFAULT_REFRESH_INTERVAL,
+            () -> IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/index/IndexServiceTests.java b/server/src/test/java/org/opensearch/index/IndexServiceTests.java
index be38b707b77b4..00c8b52d30c55 100644
--- a/server/src/test/java/org/opensearch/index/IndexServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexServiceTests.java
@@ -33,17 +33,19 @@
 package org.opensearch.index;
 
 import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TopDocs;
+import org.opensearch.Version;
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.shard.IndexShard;
@@ -51,8 +53,8 @@
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -79,7 +81,7 @@ public static CompressedXContent filter(QueryBuilder filterBuilder) throws IOExc
         XContentBuilder builder = XContentFactory.jsonBuilder();
         filterBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.close();
-        return new CompressedXContent(Strings.toString(builder));
+        return new CompressedXContent(builder.toString());
     }
 
     public void testBaseAsyncTask() throws Exception {
@@ -300,7 +302,7 @@ public void testRefreshActuallyWorks() throws Exception {
         assertEquals(1000, refreshTask.getInterval().millis());
         assertTrue(indexService.getRefreshTask().mustReschedule());
         IndexShard shard = indexService.getShard(0);
-        client().prepareIndex("test").setId("0").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("0").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         // now disable the refresh
         client().admin()
             .indices()
@@ -321,7 +323,7 @@ public void testRefreshActuallyWorks() throws Exception {
         });
         assertFalse(refreshTask.isClosed());
         // refresh every millisecond
-        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         client().admin()
             .indices()
             .prepareUpdateSettings("test")
@@ -335,7 +337,7 @@ public void testRefreshActuallyWorks() throws Exception {
                 assertEquals(2, search.totalHits.value);
             }
         });
-        client().prepareIndex("test").setId("2").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("2").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         assertBusy(() -> {
             // this one becomes visible due to the scheduled refresh
             try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
@@ -353,7 +355,7 @@ public void testAsyncFsyncActuallyWorks() throws Exception {
         IndexService indexService = createIndex("test", settings);
         ensureGreen("test");
         assertTrue(indexService.getRefreshTask().mustReschedule());
-        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         IndexShard shard = indexService.getShard(0);
         assertBusy(() -> assertFalse(shard.isSyncNeeded()));
     }
@@ -375,7 +377,7 @@ public void testRescheduleAsyncFsync() throws Exception {
 
         assertNotNull(indexService.getFsyncTask());
         assertTrue(indexService.getFsyncTask().mustReschedule());
-        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         assertNotNull(indexService.getFsyncTask());
         final IndexShard shard = indexService.getShard(0);
         assertBusy(() -> assertFalse(shard.isSyncNeeded()));
@@ -402,7 +404,7 @@ public void testAsyncTranslogTrimActuallyWorks() throws Exception {
         IndexService indexService = createIndex("test", settings);
         ensureGreen("test");
         assertTrue(indexService.getTrimTranslogTask().mustReschedule());
-        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        client().prepareIndex("test").setId("1").setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON).get();
         client().admin().indices().prepareFlush("test").get();
         client().admin()
             .indices()
@@ -429,7 +431,11 @@ public void testAsyncTranslogTrimTaskOnClosedIndex() throws Exception {
         int translogOps = 0;
         final int numDocs = scaledRandomIntBetween(10, 100);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex().setIndex(indexName).setId(String.valueOf(i)).setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+            client().prepareIndex()
+                .setIndex(indexName)
+                .setId(String.valueOf(i))
+                .setSource("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON)
+                .get();
             translogOps++;
             if (randomBoolean()) {
                 client().admin().indices().prepareFlush(indexName).get();
@@ -502,4 +508,96 @@ public void testUpdateSyncIntervalDynamically() {
         indexMetadata = client().admin().cluster().prepareState().execute().actionGet().getState().metadata().index("test");
         assertEquals("20s", indexMetadata.getSettings().get(IndexSettings.INDEX_TRANSLOG_SYNC_INTERVAL_SETTING.getKey()));
     }
+
+    public void testUpdateRemoteTranslogBufferIntervalDynamically() {
+        Settings settings = Settings.builder().put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "10s").build();
+        IndexService indexService = createIndex("test", settings);
+        ensureGreen("test");
+
+        Settings.Builder builder = Settings.builder().put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "5s");
+        client().admin().indices().prepareUpdateSettings("test").setSettings(builder).get();
+        IndexMetadata indexMetadata = client().admin().cluster().prepareState().execute().actionGet().getState().metadata().index("test");
+        assertEquals("5s", indexMetadata.getSettings().get(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey()));
+
+        client().admin().indices().prepareClose("test").get();
+        client().admin()
+            .indices()
+            .prepareUpdateSettings("test")
+            .setSettings(Settings.builder().put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "20s"))
+            .get();
+        indexMetadata = client().admin().cluster().prepareState().execute().actionGet().getState().metadata().index("test");
+        assertEquals("20s", indexMetadata.getSettings().get(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey()));
+    }
+
+    public void testIndexSort() {
+        Settings settings = Settings.builder()
+            .put(IndexSettings.INDEX_TRANSLOG_SYNC_INTERVAL_SETTING.getKey(), "0ms") // disable
+            .putList("index.sort.field", "sortfield")
+            .build();
+        try {
+            // Integer index sort should be remained to int sort type
+            IndexService index = createIndex("test", settings, createTestMapping("integer"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.INT);
+
+            // Long index sort should be remained to long sort type
+            index = createIndex("test", settings, createTestMapping("long"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.LONG);
+
+            // Float index sort should be remained to float sort type
+            index = createIndex("test", settings, createTestMapping("float"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.FLOAT);
+
+            // Double index sort should be remained to double sort type
+            index = createIndex("test", settings, createTestMapping("double"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.DOUBLE);
+
+            // String index sort should be remained to string sort type
+            index = createIndex("test", settings, createTestMapping("string"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.STRING);
+        } catch (IllegalArgumentException ex) {
+            assertEquals("failed to parse value [0ms] for setting [index.translog.sync_interval], must be >= [100ms]", ex.getMessage());
+        }
+    }
+
+    public void testIndexSortBackwardCompatible() {
+        Settings settings = Settings.builder()
+            .put(IndexSettings.INDEX_TRANSLOG_SYNC_INTERVAL_SETTING.getKey(), "0ms") // disable
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), Version.V_2_6_1)
+            .putList("index.sort.field", "sortfield")
+            .build();
+        try {
+            // Integer index sort should be converted to long sort type
+            IndexService index = createIndex("test", settings, createTestMapping("integer"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.LONG);
+
+            // Long index sort should be remained to long sort type
+            index = createIndex("test", settings, createTestMapping("long"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.LONG);
+
+            // Float index sort should be remained to float sort type
+            index = createIndex("test", settings, createTestMapping("float"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.FLOAT);
+
+            // Double index sort should be remained to double sort type
+            index = createIndex("test", settings, createTestMapping("double"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.DOUBLE);
+
+            // String index sort should be remained to string sort type
+            index = createIndex("test", settings, createTestMapping("string"));
+            assertTrue(index.getIndexSortSupplier().get().getSort()[0].getType() == SortField.Type.STRING);
+        } catch (IllegalArgumentException ex) {
+            assertEquals("failed to parse value [0ms] for setting [index.translog.sync_interval], must be >= [100ms]", ex.getMessage());
+        }
+    }
+
+    private static String createTestMapping(String type) {
+        return "  \"properties\": {\n"
+            + "    \"test\": {\n"
+            + "      \"type\": \"text\"\n"
+            + "    },\n"
+            + "    \"sortfield\": {\n"
+            + "      \"type\": \" + type + \"\n"
+            + "    }\n"
+            + "  }";
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/IndexSettingsTests.java b/server/src/test/java/org/opensearch/index/IndexSettingsTests.java
index d67534bbfbddf..3a70b9da954cc 100644
--- a/server/src/test/java/org/opensearch/index/IndexSettingsTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexSettingsTests.java
@@ -32,28 +32,34 @@
 
 package org.opensearch.index;
 
-import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.settings.AbstractScopedSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.search.pipeline.SearchPipelineService;
+import org.opensearch.test.FeatureFlagSetter;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
 
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectory.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.core.StringContains.containsString;
 import static org.hamcrest.object.HasToString.hasToString;
@@ -96,8 +102,9 @@ public void testSettingsUpdateValidator() {
         Setting<Integer> integerSetting = Setting.intSetting("index.test.setting.int", -1, Property.Dynamic, Property.IndexScope);
         IndexMetadata metadata = newIndexMeta("index", theSettings);
         IndexSettings settings = newIndexSettings(newIndexMeta("index", theSettings), Settings.EMPTY, integerSetting);
-        settings.getScopedSettings()
-            .addSettingsUpdateConsumer(integerSetting, integer::set, (i) -> { if (i == 42) throw new AssertionError("boom"); });
+        settings.getScopedSettings().addSettingsUpdateConsumer(integerSetting, integer::set, (i) -> {
+            if (i == 42) throw new AssertionError("boom");
+        });
 
         assertEquals(version, settings.getIndexVersionCreated());
         assertEquals("0xdeadbeef", settings.getUUID());
@@ -319,7 +326,7 @@ public void testIsWarmerEnabled() {
     }
 
     public void testRefreshInterval() {
-        String refreshInterval = getRandomTimeString();
+        String refreshInterval = getRandomTimeString(false);
         IndexMetadata metadata = newIndexMeta(
             "index",
             Settings.builder()
@@ -336,7 +343,7 @@ public void testRefreshInterval() {
             ),
             settings.getRefreshInterval()
         );
-        String newRefreshInterval = getRandomTimeString();
+        String newRefreshInterval = getRandomTimeString(false);
         settings.updateIndexMetadata(
             newIndexMeta("index", Settings.builder().put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), newRefreshInterval).build())
         );
@@ -350,8 +357,12 @@ public void testRefreshInterval() {
         );
     }
 
-    private String getRandomTimeString() {
-        int refreshIntervalInt = randomFrom(-1, Math.abs(randomInt()));
+    private String getRandomTimeString(boolean nonNegativeOnly) {
+        int start = -1;
+        if (nonNegativeOnly) {
+            start = 0;
+        }
+        int refreshIntervalInt = randomFrom(start, Math.abs(randomInt()));
         String refreshInterval = Integer.toString(refreshIntervalInt);
         if (refreshIntervalInt >= 0) {
             refreshInterval += randomFrom("s", "ms", "h");
@@ -650,15 +661,15 @@ public void testArchivedSettingsValidation() {
     }
 
     public void testArchiveBrokenIndexSettings() {
-        Settings settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(
-            Settings.EMPTY,
-            e -> { assert false : "should not have been invoked, no unknown settings"; },
-            (e, ex) -> { assert false : "should not have been invoked, no invalid settings"; }
-        );
+        Settings settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(Settings.EMPTY, e -> {
+            assert false : "should not have been invoked, no unknown settings";
+        }, (e, ex) -> { assert false : "should not have been invoked, no invalid settings"; });
         assertSame(settings, Settings.EMPTY);
         settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(
             Settings.builder().put("index.refresh_interval", "-200").build(),
-            e -> { assert false : "should not have been invoked, no invalid settings"; },
+            e -> {
+                assert false : "should not have been invoked, no invalid settings";
+            },
             (e, ex) -> {
                 assertThat(e.getKey(), equalTo("index.refresh_interval"));
                 assertThat(e.getValue(), equalTo("-200"));
@@ -669,11 +680,9 @@ public void testArchiveBrokenIndexSettings() {
         assertNull(settings.get("index.refresh_interval"));
 
         Settings prevSettings = settings; // no double archive
-        settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(
-            prevSettings,
-            e -> { assert false : "should not have been invoked, no unknown settings"; },
-            (e, ex) -> { assert false : "should not have been invoked, no invalid settings"; }
-        );
+        settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(prevSettings, e -> {
+            assert false : "should not have been invoked, no unknown settings";
+        }, (e, ex) -> { assert false : "should not have been invoked, no invalid settings"; });
         assertSame(prevSettings, settings);
 
         settings = IndexScopedSettings.DEFAULT_SCOPED_SETTINGS.archiveUnknownOrInvalidSettings(
@@ -723,7 +732,7 @@ public void testUpdateSoftDeletesFails() {
     public void testSoftDeletesDefaultSetting() {
         // enabled by default on 7.0+ or later
         {
-            Version createdVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, Version.CURRENT);
+            Version createdVersion = VersionUtils.randomVersionBetween(random(), Version.V_1_0_0, Version.CURRENT);
             Settings settings = Settings.builder().put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), createdVersion).build();
             assertTrue(IndexSettings.INDEX_SOFT_DELETES_SETTING.get(settings));
         }
@@ -731,10 +740,7 @@ public void testSoftDeletesDefaultSetting() {
 
     public void testIgnoreTranslogRetentionSettingsIfSoftDeletesEnabled() {
         Settings.Builder settings = Settings.builder()
-            .put(
-                IndexMetadata.SETTING_VERSION_CREATED,
-                VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_4_0, Version.CURRENT)
-            );
+            .put(IndexMetadata.SETTING_VERSION_CREATED, VersionUtils.randomVersionBetween(random(), Version.V_1_0_0, Version.CURRENT));
         if (randomBoolean()) {
             settings.put(IndexSettings.INDEX_TRANSLOG_RETENTION_AGE_SETTING.getKey(), randomPositiveTimeValue());
         }
@@ -757,4 +763,293 @@ public void testIgnoreTranslogRetentionSettingsIfSoftDeletesEnabled() {
         assertThat(indexSettings.getTranslogRetentionAge().millis(), equalTo(-1L));
         assertThat(indexSettings.getTranslogRetentionSize().getBytes(), equalTo(-1L));
     }
+
+    public void testRemoteStoreDefaultSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertFalse(settings.isRemoteStoreEnabled());
+    }
+
+    public void testRemoteStoreExplicitSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertTrue(settings.isRemoteStoreEnabled());
+    }
+
+    public void testRemoteTranslogStoreDefaultSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertFalse(settings.isRemoteTranslogStoreEnabled());
+    }
+
+    public void testEnablingRemoteStoreFailsWhenReplicationTypeIsDocument() {
+        Settings indexSettings = Settings.builder()
+            .put("index.replication.type", ReplicationType.DOCUMENT)
+            .put("index.remote_store.enabled", true)
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_STORE_ENABLED_SETTING.get(indexSettings)
+        );
+        assertEquals("To enable index.remote_store.enabled, index.replication.type should be set to SEGMENT", iae.getMessage());
+    }
+
+    public void testEnablingRemoteStoreFailsWhenReplicationTypeIsDefault() {
+        Settings indexSettings = Settings.builder().put("index.remote_store.enabled", true).build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_STORE_ENABLED_SETTING.get(indexSettings)
+        );
+        assertEquals("To enable index.remote_store.enabled, index.replication.type should be set to SEGMENT", iae.getMessage());
+    }
+
+    public void testRemoteRepositoryDefaultSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertNull(settings.getRemoteStoreRepository());
+    }
+
+    public void testRemoteRepositoryExplicitSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "repo1")
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertEquals("repo1", settings.getRemoteStoreRepository());
+    }
+
+    public void testSetRemoteRepositoryFailsWhenRemoteStoreIsNotEnabled() {
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false)
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "repo1")
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING.get(indexSettings)
+        );
+        assertEquals(
+            String.format(
+                Locale.ROOT,
+                "Settings %s can only be set/enabled when %s is set to true",
+                IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY,
+                IndexMetadata.SETTING_REMOTE_STORE_ENABLED
+            ),
+            iae.getMessage()
+        );
+    }
+
+    public void testSetRemoteRepositoryFailsWhenEmptyString() {
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false)
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "")
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_SEGMENT_STORE_REPOSITORY_SETTING.get(indexSettings)
+        );
+        assertEquals(
+            String.format(
+                Locale.ROOT,
+                "Setting %s should be provided with non-empty repository ID",
+                IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY
+            ),
+            iae.getMessage()
+        );
+    }
+
+    public void testRemoteTranslogRepoDefaultSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertNull(settings.getRemoteStoreRepository());
+    }
+
+    public void testRemoteTranslogExplicitSetting() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "tlog-store")
+                .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "200ms")
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertNull(settings.getRemoteStoreRepository());
+        assertEquals("tlog-store", settings.getRemoteStoreTranslogRepository());
+        assertEquals(TimeValue.timeValueMillis(200), settings.getRemoteTranslogUploadBufferInterval());
+    }
+
+    public void testSetRemoteTranslogRepositoryFailsWhenRemoteStoreIsNotEnabled() {
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false)
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "repo1")
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING.get(indexSettings)
+        );
+        assertEquals(
+            "Settings index.remote_store.translog.repository can only be set/enabled when index.remote_store.enabled is set to true",
+            iae.getMessage()
+        );
+    }
+
+    public void testSetRemoteTranslogRepositoryFailsWhenEmptyString() {
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "")
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexMetadata.INDEX_REMOTE_TRANSLOG_REPOSITORY_SETTING.get(indexSettings)
+        );
+        assertEquals("Setting index.remote_store.translog.repository should be provided with non-empty repository ID", iae.getMessage());
+    }
+
+    public void testSetRemoteTranslogBufferIntervalDefaultSetting() {
+        Version createdVersion = VersionUtils.randomVersionBetween(random(), Version.V_2_0_0, Version.CURRENT);
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), createdVersion)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .build();
+        assertEquals(TimeValue.timeValueMillis(650), IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(settings));
+    }
+
+    public void testSetRemoteTranslogBufferIntervalFailsWhenEmpty() {
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false)
+            .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "")
+            .build();
+        IllegalArgumentException iae = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.get(indexSettings)
+        );
+        assertEquals(
+            "failed to parse setting [index.remote_store.translog.buffer_interval] with value [] as a time value: unit is missing or unrecognized",
+            iae.getMessage()
+        );
+    }
+
+    public void testUpdateRemoteTranslogBufferInterval() {
+        String bufferInterval = getRandomTimeString(true);
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), bufferInterval)
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertEquals(
+            TimeValue.parseTimeValue(
+                bufferInterval,
+                new TimeValue(1, TimeUnit.DAYS),
+                IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey()
+            ),
+            settings.getRemoteTranslogUploadBufferInterval()
+        );
+        String newBufferInterval = getRandomTimeString(true);
+        settings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder().put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), newBufferInterval).build()
+            )
+        );
+        assertEquals(
+            TimeValue.parseTimeValue(
+                newBufferInterval,
+                new TimeValue(1, TimeUnit.DAYS),
+                IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey()
+            ),
+            settings.getRemoteTranslogUploadBufferInterval()
+        );
+    }
+
+    @SuppressForbidden(reason = "sets the SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY feature flag")
+    public void testExtendedCompatibilityVersionForRemoteSnapshot() throws Exception {
+        FeatureFlagSetter.set(FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY);
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertTrue(settings.isRemoteSnapshot());
+        assertEquals(SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION, settings.getExtendedCompatibilitySnapshotVersion());
+    }
+
+    public void testExtendedCompatibilityVersionForNonRemoteSnapshot() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey())
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertFalse(settings.isRemoteSnapshot());
+        assertEquals(Version.CURRENT.minimumIndexCompatibilityVersion(), settings.getExtendedCompatibilitySnapshotVersion());
+    }
+
+    public void testExtendedCompatibilityVersionWithoutFeatureFlag() {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                .build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertTrue(settings.isRemoteSnapshot());
+        assertEquals(Version.CURRENT.minimumIndexCompatibilityVersion(), settings.getExtendedCompatibilitySnapshotVersion());
+    }
+
+    @SuppressForbidden(reason = "sets the SEARCH_PIPELINE feature flag")
+    public void testDefaultSearchPipeline() throws Exception {
+        IndexMetadata metadata = newIndexMeta(
+            "index",
+            Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build()
+        );
+        IndexSettings settings = new IndexSettings(metadata, Settings.EMPTY);
+        assertEquals(SearchPipelineService.NOOP_PIPELINE_ID, settings.getDefaultSearchPipeline());
+        metadata = newIndexMeta(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+                .put(IndexSettings.DEFAULT_SEARCH_PIPELINE.getKey(), "foo")
+                .build()
+        );
+        settings.updateIndexMetadata(metadata);
+        assertEquals("foo", settings.getDefaultSearchPipeline());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/IndexTests.java b/server/src/test/java/org/opensearch/index/IndexTests.java
index ed845e27bfb2f..aa4661b04a25f 100644
--- a/server/src/test/java/org/opensearch/index/IndexTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexTests.java
@@ -34,19 +34,20 @@
 
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class IndexTests extends OpenSearchTestCase {
     public void testToString() {
diff --git a/server/src/test/java/org/opensearch/index/IndexingPressureServiceTests.java b/server/src/test/java/org/opensearch/index/IndexingPressureServiceTests.java
index 22d185643018a..0b657c1c9745f 100644
--- a/server/src/test/java/org/opensearch/index/IndexingPressureServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexingPressureServiceTests.java
@@ -8,7 +8,6 @@
 
 package org.opensearch.index;
 
-import org.junit.Before;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.bulk.BulkItemRequest;
@@ -21,10 +20,12 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.stats.IndexingPressurePerShardStats;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 public class IndexingPressureServiceTests extends OpenSearchTestCase {
 
diff --git a/server/src/test/java/org/opensearch/index/IndexingPressureTests.java b/server/src/test/java/org/opensearch/index/IndexingPressureTests.java
index 0f9d9c7be1395..1aa20506222d1 100644
--- a/server/src/test/java/org/opensearch/index/IndexingPressureTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexingPressureTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/IndexingSlowLogTests.java b/server/src/test/java/org/opensearch/index/IndexingSlowLogTests.java
index 38c8491d79150..b2df78b473785 100644
--- a/server/src/test/java/org/opensearch/index/IndexingSlowLogTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexingSlowLogTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.index;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.LoggerContext;
@@ -41,29 +42,31 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.logging.MockAppender;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexingSlowLog.IndexingSlowLogMessage;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.InternalEngineTests;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.Uid;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.mockito.Mockito;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.emptyOrNullString;
 import static org.hamcrest.Matchers.equalTo;
@@ -86,8 +89,8 @@ public static void init() throws IllegalAccessException {
 
     @AfterClass
     public static void cleanup() {
-        appender.stop();
         Loggers.removeAppender(testLogger1, appender);
+        appender.stop();
     }
 
     public void testLevelPrecedence() {
@@ -226,7 +229,7 @@ public void testSlowLogMessageHasJsonFields() throws IOException {
             "routingValue",
             null,
             source,
-            XContentType.JSON,
+            MediaTypeRegistry.JSON,
             null
         );
         Index index = new Index("foo", "123");
@@ -254,7 +257,7 @@ public void testSlowLogParsedDocumentPrinterSourceToLog() throws IOException {
             null,
             null,
             source,
-            XContentType.JSON,
+            MediaTypeRegistry.JSON,
             null
         );
         Index index = new Index("foo", "123");
@@ -284,7 +287,7 @@ public void testSlowLogParsedDocumentPrinterSourceToLog() throws IOException {
             null,
             null,
             source,
-            XContentType.JSON,
+            MediaTypeRegistry.JSON,
             null
         );
 
diff --git a/server/src/test/java/org/opensearch/index/MergePolicySettingsTests.java b/server/src/test/java/org/opensearch/index/MergePolicySettingsTests.java
index 4735c3a8ee3cb..32c4c048d77ba 100644
--- a/server/src/test/java/org/opensearch/index/MergePolicySettingsTests.java
+++ b/server/src/test/java/org/opensearch/index/MergePolicySettingsTests.java
@@ -31,11 +31,12 @@
 
 package org.opensearch.index;
 
+import org.apache.lucene.index.LogByteSizeMergePolicy;
 import org.apache.lucene.index.NoMergePolicy;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -49,17 +50,17 @@ public class MergePolicySettingsTests extends OpenSearchTestCase {
     protected final ShardId shardId = new ShardId("index", "_na_", 1);
 
     public void testCompoundFileSettings() throws IOException {
-        assertThat(new MergePolicyConfig(logger, indexSettings(Settings.EMPTY)).getMergePolicy().getNoCFSRatio(), equalTo(0.1));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(true))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(0.5))).getMergePolicy().getNoCFSRatio(), equalTo(0.5));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(1.0))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build("true"))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build("True"))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build("False"))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build("false"))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(false))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(0))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
-        assertThat(new MergePolicyConfig(logger, indexSettings(build(0.0))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(Settings.EMPTY)).getMergePolicy().getNoCFSRatio(), equalTo(0.1));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(true))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(0.5))).getMergePolicy().getNoCFSRatio(), equalTo(0.5));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(1.0))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build("true"))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build("True"))).getMergePolicy().getNoCFSRatio(), equalTo(1.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build("False"))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build("false"))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(false))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(0))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
+        assertThat(new TieredMergePolicyProvider(logger, indexSettings(build(0.0))).getMergePolicy().getNoCFSRatio(), equalTo(0.0));
     }
 
     private static IndexSettings indexSettings(Settings settings) {
@@ -67,33 +68,197 @@ private static IndexSettings indexSettings(Settings settings) {
     }
 
     public void testNoMerges() {
-        MergePolicyConfig mp = new MergePolicyConfig(
+        TieredMergePolicyProvider tmp = new TieredMergePolicyProvider(
             logger,
-            indexSettings(Settings.builder().put(MergePolicyConfig.INDEX_MERGE_ENABLED, false).build())
+            indexSettings(Settings.builder().put(MergePolicyProvider.INDEX_MERGE_ENABLED, false).build())
         );
-        assertTrue(mp.getMergePolicy() instanceof NoMergePolicy);
+        LogByteSizeMergePolicyProvider lbsmp = new LogByteSizeMergePolicyProvider(
+            logger,
+            indexSettings(Settings.builder().put(MergePolicyProvider.INDEX_MERGE_ENABLED, false).build())
+        );
+        assertTrue(tmp.getMergePolicy() instanceof NoMergePolicy);
+        assertTrue(lbsmp.getMergePolicy() instanceof NoMergePolicy);
     }
 
     public void testUpdateSettings() throws IOException {
-        IndexSettings indexSettings = indexSettings(EMPTY_SETTINGS);
-        assertThat(indexSettings.getMergePolicy().getNoCFSRatio(), equalTo(0.1));
+        Settings settings = Settings.builder()
+            .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.TIERED.getValue())
+            .build();
+        IndexSettings indexSettings = indexSettings(settings);
+        assertThat(indexSettings.getMergePolicy(false).getNoCFSRatio(), equalTo(0.1));
         indexSettings = indexSettings(build(0.9));
-        assertThat((indexSettings.getMergePolicy()).getNoCFSRatio(), equalTo(0.9));
+        assertThat((indexSettings.getMergePolicy(false)).getNoCFSRatio(), equalTo(0.9));
         indexSettings.updateIndexMetadata(newIndexMeta("index", build(0.1)));
-        assertThat((indexSettings.getMergePolicy()).getNoCFSRatio(), equalTo(0.1));
+        assertThat((indexSettings.getMergePolicy(false)).getNoCFSRatio(), equalTo(0.1));
         indexSettings.updateIndexMetadata(newIndexMeta("index", build(0.0)));
-        assertThat((indexSettings.getMergePolicy()).getNoCFSRatio(), equalTo(0.0));
+        assertThat((indexSettings.getMergePolicy(false)).getNoCFSRatio(), equalTo(0.0));
         indexSettings.updateIndexMetadata(newIndexMeta("index", build("true")));
-        assertThat((indexSettings.getMergePolicy()).getNoCFSRatio(), equalTo(1.0));
+        assertThat((indexSettings.getMergePolicy(false)).getNoCFSRatio(), equalTo(1.0));
         indexSettings.updateIndexMetadata(newIndexMeta("index", build("false")));
-        assertThat((indexSettings.getMergePolicy()).getNoCFSRatio(), equalTo(0.0));
+        assertThat((indexSettings.getMergePolicy(false)).getNoCFSRatio(), equalTo(0.0));
+    }
+
+    public void testDefaultMergePolicy() throws IOException {
+        IndexSettings indexSettings = indexSettings(EMPTY_SETTINGS);
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof OpenSearchTieredMergePolicy);
+    }
+
+    public void testMergePolicyPrecedence() throws IOException {
+        // 1. INDEX_MERGE_POLICY is not set
+        // assert defaults
+        IndexSettings indexSettings = indexSettings(EMPTY_SETTINGS);
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof OpenSearchTieredMergePolicy);
+
+        // 1.1 node setting TIME_SERIES_INDEX_MERGE_POLICY is set as log_byte_size
+        // assert index policy is tiered whereas time series index policy is log_byte_size
+        Settings nodeSettings = Settings.builder()
+            .put(IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+            .build();
+        indexSettings = new IndexSettings(newIndexMeta("test", Settings.EMPTY), nodeSettings);
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof LogByteSizeMergePolicy);
+
+        // 1.2 node setting TIME_SERIES_INDEX_MERGE_POLICY is set as tiered
+        // assert both index and time series index policy is tiered
+        nodeSettings = Settings.builder()
+            .put(IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.TIERED.getValue())
+            .build();
+        indexSettings = new IndexSettings(newIndexMeta("test", Settings.EMPTY), nodeSettings);
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof OpenSearchTieredMergePolicy);
+
+        // 2. INDEX_MERGE_POLICY set as tiered
+        // assert both index and time-series-index merge policy is set as tiered
+        indexSettings = indexSettings(
+            Settings.builder().put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.TIERED.getValue()).build()
+        );
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof OpenSearchTieredMergePolicy);
+
+        // 2.1 node setting TIME_SERIES_INDEX_MERGE_POLICY is set as log_byte_size
+        // assert both index and time-series-index merge policy is set as tiered
+        nodeSettings = Settings.builder()
+            .put(IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+            .build();
+        indexSettings = new IndexSettings(
+            newIndexMeta(
+                "test",
+                Settings.builder().put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.TIERED.getValue()).build()
+            ),
+            nodeSettings
+        );
+        assertTrue(indexSettings.getMergePolicy(false) instanceof OpenSearchTieredMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof OpenSearchTieredMergePolicy);
+
+        // 3. INDEX_MERGE_POLICY set as log_byte_size
+        // assert both index and time-series-index merge policy is set as log_byte_size
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+                .build()
+        );
+        assertTrue(indexSettings.getMergePolicy(false) instanceof LogByteSizeMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof LogByteSizeMergePolicy);
+
+        // 3.1 node setting TIME_SERIES_INDEX_MERGE_POLICY is set as tiered
+        // assert both index and time-series-index merge policy is set as log_byte_size
+        nodeSettings = Settings.builder()
+            .put(IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.TIERED.getValue())
+            .build();
+        indexSettings = new IndexSettings(
+            newIndexMeta(
+                "test",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+                    .build()
+            ),
+            nodeSettings
+        );
+        assertTrue(indexSettings.getMergePolicy(false) instanceof LogByteSizeMergePolicy);
+        assertTrue(indexSettings.getMergePolicy(true) instanceof LogByteSizeMergePolicy);
+
+    }
+
+    public void testInvalidMergePolicy() throws IOException {
+
+        final Settings invalidSettings = Settings.builder().put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "invalid").build();
+        IllegalArgumentException exc1 = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexSettings.INDEX_MERGE_POLICY.get(invalidSettings)
+        );
+        assertThat(exc1.getMessage(), containsString(" has unsupported policy specified: "));
+        IllegalArgumentException exc2 = expectThrows(
+            IllegalArgumentException.class,
+            () -> indexSettings(invalidSettings).getMergePolicy(false)
+        );
+        assertThat(exc2.getMessage(), containsString(" has unsupported policy specified: "));
+
+        final Settings invalidSettings2 = Settings.builder().put(IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.getKey(), "invalid").build();
+        IllegalArgumentException exc3 = expectThrows(
+            IllegalArgumentException.class,
+            () -> IndexSettings.TIME_SERIES_INDEX_MERGE_POLICY.get(invalidSettings2)
+        );
+        assertThat(exc3.getMessage(), containsString(" has unsupported policy specified: "));
+
+        IllegalArgumentException exc4 = expectThrows(
+            IllegalArgumentException.class,
+            () -> new IndexSettings(newIndexMeta("test", Settings.EMPTY), invalidSettings2).getMergePolicy(true)
+        );
+        assertThat(exc4.getMessage(), containsString(" has unsupported policy specified: "));
+    }
+
+    public void testUpdateSettingsForLogByteSizeMergePolicy() throws IOException {
+        IndexSettings indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+                .build()
+        );
+        assertTrue(indexSettings.getMergePolicy(true) instanceof LogByteSizeMergePolicy);
+        assertThat(indexSettings.getMergePolicy(true).getNoCFSRatio(), equalTo(0.1));
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), 0.9)
+                .build()
+        );
+        assertThat((indexSettings.getMergePolicy(true)).getNoCFSRatio(), equalTo(0.9));
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), 0.1)
+                .build()
+        );
+        assertThat((indexSettings.getMergePolicy(true)).getNoCFSRatio(), equalTo(0.1));
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), 0.0)
+                .build()
+        );
+        assertThat((indexSettings.getMergePolicy(true)).getNoCFSRatio(), equalTo(0.0));
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), "true")
+                .build()
+        );
+        assertThat((indexSettings.getMergePolicy(true)).getNoCFSRatio(), equalTo(1.0));
+        indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), "false")
+                .build()
+        );
+        assertThat((indexSettings.getMergePolicy(true)).getNoCFSRatio(), equalTo(0.0));
     }
 
     public void testTieredMergePolicySettingsUpdate() throws IOException {
         IndexSettings indexSettings = indexSettings(Settings.EMPTY);
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getForceMergeDeletesPctAllowed(),
-            MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getForceMergeDeletesPctAllowed(),
+            TieredMergePolicyProvider.DEFAULT_EXPUNGE_DELETES_ALLOWED,
             0.0d
         );
 
@@ -102,21 +267,21 @@ public void testTieredMergePolicySettingsUpdate() throws IOException {
                 "index",
                 Settings.builder()
                     .put(
-                        MergePolicyConfig.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING.getKey(),
-                        MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d
+                        TieredMergePolicyProvider.INDEX_MERGE_POLICY_EXPUNGE_DELETES_ALLOWED_SETTING.getKey(),
+                        TieredMergePolicyProvider.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d
                     )
                     .build()
             )
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getForceMergeDeletesPctAllowed(),
-            MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getForceMergeDeletesPctAllowed(),
+            TieredMergePolicyProvider.DEFAULT_EXPUNGE_DELETES_ALLOWED + 1.0d,
             0.0d
         );
 
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getFloorSegmentMB(),
-            MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getFloorSegmentMB(),
+            TieredMergePolicyProvider.DEFAULT_FLOOR_SEGMENT.getMbFrac(),
             0
         );
         indexSettings.updateIndexMetadata(
@@ -124,41 +289,41 @@ public void testTieredMergePolicySettingsUpdate() throws IOException {
                 "index",
                 Settings.builder()
                     .put(
-                        MergePolicyConfig.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING.getKey(),
-                        new ByteSizeValue(MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.getMb() + 1, ByteSizeUnit.MB)
+                        TieredMergePolicyProvider.INDEX_MERGE_POLICY_FLOOR_SEGMENT_SETTING.getKey(),
+                        new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_FLOOR_SEGMENT.getMb() + 1, ByteSizeUnit.MB)
                     )
                     .build()
             )
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getFloorSegmentMB(),
-            new ByteSizeValue(MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.getMb() + 1, ByteSizeUnit.MB).getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getFloorSegmentMB(),
+            new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_FLOOR_SEGMENT.getMb() + 1, ByteSizeUnit.MB).getMbFrac(),
             0.001
         );
 
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergeAtOnce(),
-            MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergeAtOnce(),
+            TieredMergePolicyProvider.DEFAULT_MAX_MERGE_AT_ONCE
         );
         indexSettings.updateIndexMetadata(
             newIndexMeta(
                 "index",
                 Settings.builder()
                     .put(
-                        MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(),
-                        MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE - 1
+                        TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(),
+                        TieredMergePolicyProvider.DEFAULT_MAX_MERGE_AT_ONCE - 1
                     )
                     .build()
             )
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergeAtOnce(),
-            MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE - 1
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergeAtOnce(),
+            TieredMergePolicyProvider.DEFAULT_MAX_MERGE_AT_ONCE - 1
         );
 
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergedSegmentMB(),
-            MergePolicyConfig.DEFAULT_MAX_MERGED_SEGMENT.getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergedSegmentMB(),
+            TieredMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getMbFrac(),
             0.0001
         );
         indexSettings.updateIndexMetadata(
@@ -166,21 +331,21 @@ public void testTieredMergePolicySettingsUpdate() throws IOException {
                 "index",
                 Settings.builder()
                     .put(
-                        MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING.getKey(),
-                        new ByteSizeValue(MergePolicyConfig.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1)
+                        TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGED_SEGMENT_SETTING.getKey(),
+                        new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1)
                     )
                     .build()
             )
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergedSegmentMB(),
-            new ByteSizeValue(MergePolicyConfig.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1).getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergedSegmentMB(),
+            new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1).getMbFrac(),
             0.0001
         );
 
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getSegmentsPerTier(),
-            MergePolicyConfig.DEFAULT_SEGMENTS_PER_TIER,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getSegmentsPerTier(),
+            TieredMergePolicyProvider.DEFAULT_SEGMENTS_PER_TIER,
             0
         );
         indexSettings.updateIndexMetadata(
@@ -188,37 +353,37 @@ public void testTieredMergePolicySettingsUpdate() throws IOException {
                 "index",
                 Settings.builder()
                     .put(
-                        MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(),
-                        MergePolicyConfig.DEFAULT_SEGMENTS_PER_TIER + 1
+                        TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(),
+                        TieredMergePolicyProvider.DEFAULT_SEGMENTS_PER_TIER + 1
                     )
                     .build()
             )
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getSegmentsPerTier(),
-            MergePolicyConfig.DEFAULT_SEGMENTS_PER_TIER + 1,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getSegmentsPerTier(),
+            TieredMergePolicyProvider.DEFAULT_SEGMENTS_PER_TIER + 1,
             0
         );
 
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getDeletesPctAllowed(),
-            MergePolicyConfig.DEFAULT_DELETES_PCT_ALLOWED,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getDeletesPctAllowed(),
+            TieredMergePolicyProvider.DEFAULT_DELETES_PCT_ALLOWED,
             0
         );
         indexSettings.updateIndexMetadata(
             newIndexMeta(
                 "index",
-                Settings.builder().put(MergePolicyConfig.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING.getKey(), 22).build()
+                Settings.builder().put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING.getKey(), 22).build()
             )
         );
-        assertEquals(((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getDeletesPctAllowed(), 22, 0);
+        assertEquals(((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getDeletesPctAllowed(), 22, 0);
 
         IllegalArgumentException exc = expectThrows(
             IllegalArgumentException.class,
             () -> indexSettings.updateIndexMetadata(
                 newIndexMeta(
                     "index",
-                    Settings.builder().put(MergePolicyConfig.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING.getKey(), 53).build()
+                    Settings.builder().put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_DELETES_PCT_ALLOWED_SETTING.getKey(), 53).build()
                 )
             )
         );
@@ -226,50 +391,162 @@ public void testTieredMergePolicySettingsUpdate() throws IOException {
         assertThat(cause.getMessage(), containsString("must be <= 50.0"));
         indexSettings.updateIndexMetadata(newIndexMeta("index", EMPTY_SETTINGS)); // see if defaults are restored
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getForceMergeDeletesPctAllowed(),
-            MergePolicyConfig.DEFAULT_EXPUNGE_DELETES_ALLOWED,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getForceMergeDeletesPctAllowed(),
+            TieredMergePolicyProvider.DEFAULT_EXPUNGE_DELETES_ALLOWED,
             0.0d
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getFloorSegmentMB(),
-            new ByteSizeValue(MergePolicyConfig.DEFAULT_FLOOR_SEGMENT.getMb(), ByteSizeUnit.MB).getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getFloorSegmentMB(),
+            new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_FLOOR_SEGMENT.getMb(), ByteSizeUnit.MB).getMbFrac(),
             0.00
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergeAtOnce(),
-            MergePolicyConfig.DEFAULT_MAX_MERGE_AT_ONCE
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergeAtOnce(),
+            TieredMergePolicyProvider.DEFAULT_MAX_MERGE_AT_ONCE
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getMaxMergedSegmentMB(),
-            new ByteSizeValue(MergePolicyConfig.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1).getMbFrac(),
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getMaxMergedSegmentMB(),
+            new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getBytes() + 1).getMbFrac(),
             0.0001
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getSegmentsPerTier(),
-            MergePolicyConfig.DEFAULT_SEGMENTS_PER_TIER,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getSegmentsPerTier(),
+            TieredMergePolicyProvider.DEFAULT_SEGMENTS_PER_TIER,
             0
         );
         assertEquals(
-            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy()).getDeletesPctAllowed(),
-            MergePolicyConfig.DEFAULT_DELETES_PCT_ALLOWED,
+            ((OpenSearchTieredMergePolicy) indexSettings.getMergePolicy(false)).getDeletesPctAllowed(),
+            TieredMergePolicyProvider.DEFAULT_DELETES_PCT_ALLOWED,
             0
         );
     }
 
+    public void testLogByteSizeMergePolicySettingsUpdate() throws IOException {
+
+        IndexSettings indexSettings = indexSettings(
+            Settings.builder()
+                .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), IndexSettings.IndexMergePolicy.LOG_BYTE_SIZE.getValue())
+                .build()
+        );
+        assertEquals(
+            ((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMergeFactor(),
+            LogByteSizeMergePolicyProvider.DEFAULT_MERGE_FACTOR
+        );
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(
+                        LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MERGE_FACTOR_SETTING.getKey(),
+                        LogByteSizeMergePolicyProvider.DEFAULT_MERGE_FACTOR + 1
+                    )
+                    .build()
+            )
+        );
+        assertEquals(
+            ((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMergeFactor(),
+            LogByteSizeMergePolicyProvider.DEFAULT_MERGE_FACTOR + 1
+        );
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(
+                        LogByteSizeMergePolicyProvider.INDEX_LBS_MERGE_POLICY_MIN_MERGE_SETTING.getKey(),
+                        new ByteSizeValue(LogByteSizeMergePolicyProvider.DEFAULT_MIN_MERGE.getMb() + 1, ByteSizeUnit.MB)
+                    )
+                    .build()
+            )
+        );
+
+        assertEquals(
+            ((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMinMergeMB(),
+            new ByteSizeValue(LogByteSizeMergePolicyProvider.DEFAULT_MIN_MERGE.getMb() + 1, ByteSizeUnit.MB).getMbFrac(),
+            0.001
+        );
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(
+                        LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_SETTING.getKey(),
+                        new ByteSizeValue(LogByteSizeMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getMb() + 100, ByteSizeUnit.MB)
+                    )
+                    .build()
+            )
+        );
+
+        assertEquals(
+            ((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMaxMergeMB(),
+            new ByteSizeValue(TieredMergePolicyProvider.DEFAULT_MAX_MERGED_SEGMENT.getMb() + 100, ByteSizeUnit.MB).getMbFrac(),
+            0.001
+        );
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(
+                        LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGE_SEGMENT_FOR_FORCED_MERGE_SETTING.getKey(),
+                        new ByteSizeValue(
+                            LogByteSizeMergePolicyProvider.DEFAULT_MAX_MERGE_SEGMENT_FORCE_MERGE.getMb() - 100,
+                            ByteSizeUnit.MB
+                        )
+                    )
+                    .build()
+            )
+        );
+        assertEquals(
+            ((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMaxMergeMBForForcedMerge(),
+            new ByteSizeValue(LogByteSizeMergePolicyProvider.DEFAULT_MAX_MERGE_SEGMENT_FORCE_MERGE.getMb() - 100, ByteSizeUnit.MB)
+                .getMbFrac(),
+            0.001
+        );
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(LogByteSizeMergePolicyProvider.INDEX_LBS_MAX_MERGED_DOCS_SETTING.getKey(), 10000000)
+                    .build()
+            )
+        );
+        assertEquals(((LogByteSizeMergePolicy) indexSettings.getMergePolicy(true)).getMaxMergeDocs(), 10000000);
+
+        indexSettings.updateIndexMetadata(
+            newIndexMeta(
+                "index",
+                Settings.builder()
+                    .put(IndexSettings.INDEX_MERGE_POLICY.getKey(), "log_byte_size")
+                    .put(LogByteSizeMergePolicyProvider.INDEX_LBS_NO_CFS_RATIO_SETTING.getKey(), 0.1)
+                    .build()
+            )
+        );
+        assertEquals(indexSettings.getMergePolicy(true).getNoCFSRatio(), 0.1, 0.0);
+    }
+
     public Settings build(String value) {
-        return Settings.builder().put(MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
+        return Settings.builder().put(TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
     }
 
     public Settings build(double value) {
-        return Settings.builder().put(MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
+        return Settings.builder().put(TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
     }
 
     public Settings build(int value) {
-        return Settings.builder().put(MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
+        return Settings.builder().put(TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
     }
 
     public Settings build(boolean value) {
-        return Settings.builder().put(MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
+        return Settings.builder().put(TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING.getKey(), value).build();
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/index/MergeSchedulerSettingsTests.java b/server/src/test/java/org/opensearch/index/MergeSchedulerSettingsTests.java
index b909846d3b681..baaf584702f78 100644
--- a/server/src/test/java/org/opensearch/index/MergeSchedulerSettingsTests.java
+++ b/server/src/test/java/org/opensearch/index/MergeSchedulerSettingsTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index;
 
 import org.apache.logging.log4j.Level;
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.appender.AbstractAppender;
 import org.apache.logging.log4j.core.filter.RegexFilter;
@@ -92,8 +92,8 @@ public void testUpdateAutoThrottleSettings() throws Exception {
                 .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
                 .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
                 .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
-                .put(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
-                .put(MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
+                .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
+                .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
                 .put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "1")
                 .put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "2")
                 .put(MergeSchedulerConfig.AUTO_THROTTLE_SETTING.getKey(), "true");
@@ -123,8 +123,8 @@ public void testUpdateMergeMaxThreadCount() throws Exception {
                 .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
                 .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
                 .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "0")
-                .put(MergePolicyConfig.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
-                .put(MergePolicyConfig.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
+                .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_MAX_MERGE_AT_ONCE_SETTING.getKey(), "2")
+                .put(TieredMergePolicyProvider.INDEX_MERGE_POLICY_SEGMENTS_PER_TIER_SETTING.getKey(), "2")
                 .put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "10000")
                 .put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "10000");
             IndexSettings settings = new IndexSettings(newIndexMeta("index", builder.build()), Settings.EMPTY);
diff --git a/server/src/test/java/org/opensearch/index/OpenSearchTieredMergePolicyTests.java b/server/src/test/java/org/opensearch/index/OpenSearchTieredMergePolicyTests.java
index cbc439041666f..614dacd457782 100644
--- a/server/src/test/java/org/opensearch/index/OpenSearchTieredMergePolicyTests.java
+++ b/server/src/test/java/org/opensearch/index/OpenSearchTieredMergePolicyTests.java
@@ -32,9 +32,18 @@
 
 package org.opensearch.index;
 
+import org.apache.lucene.index.MergePolicy;
+import org.apache.lucene.index.SegmentCommitInfo;
+import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.TieredMergePolicy;
+import org.apache.lucene.util.InfoStream;
+import org.apache.lucene.util.Version;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Set;
+
 public class OpenSearchTieredMergePolicyTests extends OpenSearchTestCase {
 
     public void testDefaults() {
@@ -80,4 +89,32 @@ public void testSetDeletesPctAllowed() {
         policy.setDeletesPctAllowed(42);
         assertEquals(42, policy.regularMergePolicy.getDeletesPctAllowed(), 0);
     }
+
+    public void testFindDeleteMergesReturnsNullOnEmptySegmentInfos() throws IOException {
+        MergePolicy.MergeSpecification mergeSpecification = new OpenSearchTieredMergePolicy().findForcedDeletesMerges(
+            new SegmentInfos(Version.LATEST.major),
+            new MergePolicy.MergeContext() {
+                @Override
+                public int numDeletesToMerge(SegmentCommitInfo info) {
+                    return 0;
+                }
+
+                @Override
+                public int numDeletedDocs(SegmentCommitInfo info) {
+                    return 0;
+                }
+
+                @Override
+                public InfoStream getInfoStream() {
+                    return InfoStream.NO_OUTPUT;
+                }
+
+                @Override
+                public Set<SegmentCommitInfo> getMergingSegments() {
+                    return Collections.emptySet();
+                }
+            }
+        );
+        assertNull(mergeSpecification);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/SearchSlowLogTests.java b/server/src/test/java/org/opensearch/index/SearchSlowLogTests.java
index ae159092a4833..7835916e14581 100644
--- a/server/src/test/java/org/opensearch/index/SearchSlowLogTests.java
+++ b/server/src/test/java/org/opensearch/index/SearchSlowLogTests.java
@@ -44,8 +44,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.internal.ShardSearchRequest;
@@ -84,9 +84,9 @@ public static void init() throws IllegalAccessException {
 
     @AfterClass
     public static void cleanup() {
-        appender.stop();
         Loggers.removeAppender(queryLog, appender);
         Loggers.removeAppender(fetchLog, appender);
+        appender.stop();
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/index/SegmentReplicationPressureServiceTests.java b/server/src/test/java/org/opensearch/index/SegmentReplicationPressureServiceTests.java
new file mode 100644
index 0000000000000..34fa13f0ba62c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/SegmentReplicationPressureServiceTests.java
@@ -0,0 +1,283 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index;
+
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+
+import static java.util.Arrays.asList;
+import static org.opensearch.index.SegmentReplicationPressureService.MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING;
+import static org.opensearch.index.SegmentReplicationPressureService.MAX_REPLICATION_TIME_BACKPRESSURE_SETTING;
+import static org.opensearch.index.SegmentReplicationPressureService.SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationPressureServiceTests extends OpenSearchIndexLevelReplicationTestCase {
+
+    private static ShardStateAction shardStateAction = Mockito.mock(ShardStateAction.class);
+    private static final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+        .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueSeconds(5))
+        .build();
+
+    public void testIsSegrepLimitBreached() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+
+            indexInBatches(5, shards, primaryShard);
+
+            SegmentReplicationStats segmentReplicationStats = service.nodeStats();
+            Map<ShardId, SegmentReplicationPerGroupStats> shardStats = segmentReplicationStats.getShardStats();
+            assertEquals(1, shardStats.size());
+            SegmentReplicationPerGroupStats groupStats = shardStats.get(primaryShard.shardId());
+            assertEquals(0, groupStats.getRejectedRequestCount());
+            Set<SegmentReplicationShardStats> replicas = groupStats.getReplicaStats();
+            assertEquals(1, replicas.size());
+            SegmentReplicationShardStats replicaStats = replicas.stream().findFirst().get();
+            assertEquals(5, replicaStats.getCheckpointsBehindCount());
+
+            assertBusy(
+                () -> expectThrows(OpenSearchRejectedExecutionException.class, () -> service.isSegrepLimitBreached(primaryShard.shardId())),
+                30,
+                TimeUnit.SECONDS
+            );
+            assertBusy(
+                () -> expectThrows(OpenSearchRejectedExecutionException.class, () -> service.isSegrepLimitBreached(primaryShard.shardId())),
+                30,
+                TimeUnit.SECONDS
+            );
+
+            // let shard catch up
+            replicateSegments(primaryShard, shards.getReplicas());
+
+            segmentReplicationStats = service.nodeStats();
+            shardStats = segmentReplicationStats.getShardStats();
+            assertEquals(1, shardStats.size());
+            groupStats = shardStats.get(primaryShard.shardId());
+            assertEquals(2, groupStats.getRejectedRequestCount());
+            replicas = groupStats.getReplicaStats();
+            assertEquals(1, replicas.size());
+            replicaStats = replicas.stream().findFirst().get();
+            assertEquals(0, replicaStats.getCheckpointsBehindCount());
+
+            service.isSegrepLimitBreached(primaryShard.shardId());
+        }
+    }
+
+    public void testIsSegrepLimitBreached_onlyCheckpointLimitBreached() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+            .build();
+
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+
+            indexInBatches(5, shards, primaryShard);
+
+            Set<SegmentReplicationShardStats> replicationStats = primaryShard.getReplicationStatsForTrackedReplicas();
+            assertEquals(1, replicationStats.size());
+            SegmentReplicationShardStats shardStats = replicationStats.stream().findFirst().get();
+            assertEquals(5, shardStats.getCheckpointsBehindCount());
+
+            service.isSegrepLimitBreached(primaryShard.shardId());
+
+            replicateSegments(primaryShard, shards.getReplicas());
+            service.isSegrepLimitBreached(primaryShard.shardId());
+            final SegmentReplicationStats segmentReplicationStats = service.nodeStats();
+            assertEquals(0, segmentReplicationStats.getShardStats().get(primaryShard.shardId()).getRejectedRequestCount());
+        }
+    }
+
+    public void testIsSegrepLimitBreached_onlyTimeLimitBreached() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+            .build();
+
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            final SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+
+            indexInBatches(1, shards, primaryShard);
+
+            assertBusy(() -> {
+                Set<SegmentReplicationShardStats> replicationStats = primaryShard.getReplicationStatsForTrackedReplicas();
+                assertEquals(1, replicationStats.size());
+                SegmentReplicationShardStats shardStats = replicationStats.stream().findFirst().get();
+                assertTrue(shardStats.getCurrentReplicationTimeMillis() > TimeValue.timeValueSeconds(5).millis());
+            });
+
+            service.isSegrepLimitBreached(primaryShard.shardId());
+            replicateSegments(primaryShard, shards.getReplicas());
+            service.isSegrepLimitBreached(primaryShard.shardId());
+            final SegmentReplicationStats segmentReplicationStats = service.nodeStats();
+            assertEquals(0, segmentReplicationStats.getShardStats().get(primaryShard.shardId()).getRejectedRequestCount());
+        }
+    }
+
+    public void testIsSegrepLimitBreached_underStaleNodeLimit() throws Exception {
+        try (ReplicationGroup shards = createGroup(3, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            indexInBatches(5, shards, primaryShard);
+            SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+
+            assertBusy(() -> {
+                Set<SegmentReplicationShardStats> replicationStats = primaryShard.getReplicationStatsForTrackedReplicas();
+                assertEquals(3, replicationStats.size());
+                SegmentReplicationShardStats shardStats = replicationStats.stream().findFirst().get();
+                assertTrue(shardStats.getCurrentReplicationTimeMillis() > TimeValue.timeValueSeconds(5).millis());
+            });
+
+            expectThrows(OpenSearchRejectedExecutionException.class, () -> service.isSegrepLimitBreached(primaryShard.shardId()));
+
+            SegmentReplicationStats segmentReplicationStats = service.nodeStats();
+            assertEquals(1, segmentReplicationStats.getShardStats().get(primaryShard.shardId()).getRejectedRequestCount());
+
+            // update one replica. 2/3 stale.
+            final List<IndexShard> replicas = shards.getReplicas();
+            replicateSegments(primaryShard, asList(replicas.get(0)));
+
+            expectThrows(OpenSearchRejectedExecutionException.class, () -> service.isSegrepLimitBreached(primaryShard.shardId()));
+
+            segmentReplicationStats = service.nodeStats();
+            assertEquals(2, segmentReplicationStats.getShardStats().get(primaryShard.shardId()).getRejectedRequestCount());
+
+            // update second replica - 1/3 stale - should not throw.
+            replicateSegments(primaryShard, asList(replicas.get(1)));
+            service.isSegrepLimitBreached(primaryShard.shardId());
+
+            // catch up all.
+            replicateSegments(primaryShard, shards.getReplicas());
+            service.isSegrepLimitBreached(primaryShard.shardId());
+        }
+    }
+
+    public void testFailStaleReplicaTask() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+            .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueMillis(10))
+            .put(MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING.getKey(), TimeValue.timeValueMillis(20))
+            .build();
+
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+
+            // index docs in batches without refreshing
+            indexInBatches(5, shards, primaryShard);
+
+            // assert that replica shard is few checkpoints behind primary
+            Set<SegmentReplicationShardStats> replicationStats = primaryShard.getReplicationStatsForTrackedReplicas();
+            assertEquals(1, replicationStats.size());
+            SegmentReplicationShardStats shardStats = replicationStats.stream().findFirst().get();
+            assertEquals(5, shardStats.getCheckpointsBehindCount());
+
+            // call the background task
+            service.getFailStaleReplicaTask().runInternal();
+
+            // verify that remote shard failed method is called which fails the replica shards falling behind.
+            verify(shardStateAction, times(1)).remoteShardFailed(any(), anyString(), anyLong(), anyBoolean(), anyString(), any(), any());
+            replicateSegments(primaryShard, shards.getReplicas());
+        }
+    }
+
+    public void testFailStaleReplicaTaskDisabled() throws Exception {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(SEGMENT_REPLICATION_INDEXING_PRESSURE_ENABLED.getKey(), true)
+            .put(MAX_REPLICATION_TIME_BACKPRESSURE_SETTING.getKey(), TimeValue.timeValueMillis(10))
+            .put(MAX_REPLICATION_LIMIT_STALE_REPLICA_SETTING.getKey(), TimeValue.timeValueMillis(0))
+            .build();
+
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            SegmentReplicationPressureService service = buildPressureService(settings, primaryShard);
+            Mockito.reset(shardStateAction);
+
+            // index docs in batches without refreshing
+            indexInBatches(5, shards, primaryShard);
+
+            // assert that replica shard is few checkpoints behind primary
+            Set<SegmentReplicationShardStats> replicationStats = primaryShard.getReplicationStatsForTrackedReplicas();
+            assertEquals(1, replicationStats.size());
+            SegmentReplicationShardStats shardStats = replicationStats.stream().findFirst().get();
+            assertEquals(5, shardStats.getCheckpointsBehindCount());
+
+            // call the background task
+            service.getFailStaleReplicaTask().runInternal();
+
+            // verify that remote shard failed method is never called as it is disabled.
+            verify(shardStateAction, never()).remoteShardFailed(any(), anyString(), anyLong(), anyBoolean(), anyString(), any(), any());
+            replicateSegments(primaryShard, shards.getReplicas());
+        }
+    }
+
+    private int indexInBatches(int count, ReplicationGroup shards, IndexShard primaryShard) throws Exception {
+        int totalDocs = 0;
+        for (int i = 0; i < count; i++) {
+            int numDocs = randomIntBetween(100, 200);
+            totalDocs += numDocs;
+            shards.indexDocs(numDocs);
+            primaryShard.refresh("Test");
+        }
+        return totalDocs;
+    }
+
+    private SegmentReplicationPressureService buildPressureService(Settings settings, IndexShard primaryShard) {
+        IndicesService indicesService = mock(IndicesService.class);
+        IndexService indexService = mock(IndexService.class);
+        when(indicesService.iterator()).thenAnswer((Answer<Iterator<IndexService>>) invocation -> List.of(indexService).iterator());
+        when(indexService.iterator()).thenAnswer((Answer<Iterator<IndexShard>>) invocation -> List.of(primaryShard).iterator());
+        when(indicesService.indexService(primaryShard.shardId().getIndex())).thenReturn(indexService);
+        when(indexService.getShard(primaryShard.shardId().id())).thenReturn(primaryShard);
+        ClusterService clusterService = mock(ClusterService.class);
+        when(clusterService.getClusterSettings()).thenReturn(new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS));
+
+        return new SegmentReplicationPressureService(settings, clusterService, indicesService, shardStateAction, mock(ThreadPool.class));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/ShardIndexingPressureConcurrentExecutionTests.java b/server/src/test/java/org/opensearch/index/ShardIndexingPressureConcurrentExecutionTests.java
index 72ca8bff4087d..ce719a18898f8 100644
--- a/server/src/test/java/org/opensearch/index/ShardIndexingPressureConcurrentExecutionTests.java
+++ b/server/src/test/java/org/opensearch/index/ShardIndexingPressureConcurrentExecutionTests.java
@@ -8,21 +8,28 @@
 
 package org.opensearch.index;
 
-import org.hamcrest.Matchers;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.stats.IndexingPressurePerShardStats;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.index.stats.ShardIndexingPressureStats;
 import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.Matcher;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static org.hamcrest.Matchers.allOf;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+
 public class ShardIndexingPressureConcurrentExecutionTests extends OpenSearchTestCase {
 
     private final Settings settings = Settings.builder()
@@ -34,8 +41,8 @@ public class ShardIndexingPressureConcurrentExecutionTests extends OpenSearchTes
         .put(ShardIndexingPressureSettings.REQUEST_SIZE_WINDOW.getKey(), 100)
         .build();
 
-    final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
-    final ClusterService clusterService = new ClusterService(settings, clusterSettings, null);
+    private final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+    private final ClusterService clusterService = new ClusterService(settings, clusterSettings, null);
 
     public enum OperationType {
         COORDINATING,
@@ -71,15 +78,11 @@ public void testCoordinatingPrimaryThreadedUpdateToShardLimits() throws Exceptio
             NUM_THREADS * 15,
             shardIndexingPressure.shardStats().getIndexingPressureShardStats(shardId1).getCurrentCombinedCoordinatingAndPrimaryBytes()
         );
-        assertTrue(
+        MatcherAssert.assertThat(
             (double) (NUM_THREADS * 15) / shardIndexingPressure.shardStats()
                 .getIndexingPressureShardStats(shardId1)
-                .getCurrentPrimaryAndCoordinatingLimits() < 0.95
-        );
-        assertTrue(
-            (double) (NUM_THREADS * 15) / shardIndexingPressure.shardStats()
-                .getIndexingPressureShardStats(shardId1)
-                .getCurrentPrimaryAndCoordinatingLimits() > 0.75
+                .getCurrentPrimaryAndCoordinatingLimits(),
+            isInOperatingFactorRange()
         );
 
         for (int i = 0; i < NUM_THREADS; i++) {
@@ -112,15 +115,11 @@ public void testReplicaThreadedUpdateToShardLimits() throws Exception {
         Releasable[] releasable = fireConcurrentRequests(NUM_THREADS, shardIndexingPressure, shardId1, 15, OperationType.REPLICA);
 
         assertEquals(NUM_THREADS * 15, shardIndexingPressure.shardStats().getIndexingPressureShardStats(shardId1).getCurrentReplicaBytes());
-        assertTrue(
-            (double) (NUM_THREADS * 15) / shardIndexingPressure.shardStats()
-                .getIndexingPressureShardStats(shardId1)
-                .getCurrentReplicaLimits() < 0.95
-        );
-        assertTrue(
+        MatcherAssert.assertThat(
             (double) (NUM_THREADS * 15) / shardIndexingPressure.shardStats()
                 .getIndexingPressureShardStats(shardId1)
-                .getCurrentReplicaLimits() > 0.75
+                .getCurrentReplicaLimits(),
+            isInOperatingFactorRange()
         );
 
         for (int i = 0; i < NUM_THREADS; i++) {
@@ -271,7 +270,13 @@ public void testCoordinatingPrimaryThreadedUpdateToShardLimitsAndRejections() th
 
         nodeStats = shardIndexingPressure.stats();
         IndexingPressurePerShardStats shardStoreStats = shardIndexingPressure.shardStats().getIndexingPressureShardStats(shardId1);
-        assertNull(shardStoreStats);
+        // If rejection count equals NUM_THREADS that means rejections happened until the last request, then we'll get shardStoreStats which
+        // was updated on the last request. In other cases, the shardStoreStats simply moves to the cold store and null is returned.
+        if (rejectionCount.get() == NUM_THREADS) {
+            assertEquals(10, shardStoreStats.getCurrentPrimaryAndCoordinatingLimits());
+        } else {
+            assertNull(shardStoreStats);
+        }
         shardStats = shardIndexingPressure.coldStats();
         if (randomBoolean) {
             assertEquals(rejectionCount.get(), nodeStats.getCoordinatingRejections());
@@ -333,7 +338,13 @@ public void testReplicaThreadedUpdateToShardLimitsAndRejections() throws Excepti
         assertEquals(0, nodeStats.getCurrentReplicaBytes());
 
         IndexingPressurePerShardStats shardStoreStats = shardIndexingPressure.shardStats().getIndexingPressureShardStats(shardId1);
-        assertNull(shardStoreStats);
+        // If rejection count equals NUM_THREADS that means rejections happened until the last request, then we'll get shardStoreStats which
+        // was updated on the last request. In other cases, the shardStoreStats simply moves to the cold store and null is returned.
+        if (rejectionCount.get() == NUM_THREADS) {
+            assertEquals(15, shardStoreStats.getCurrentReplicaLimits());
+        } else {
+            assertNull(shardStoreStats);
+        }
 
         shardStats = shardIndexingPressure.coldStats();
         assertEquals(rejectionCount.get(), shardStats.getIndexingPressureShardStats(shardId1).getReplicaNodeLimitsBreachedRejections());
@@ -1087,4 +1098,11 @@ private void fireConcurrentAndParallelRequestsForUniformThroughPut(
             t.join();
         }
     }
+
+    private Matcher<Double> isInOperatingFactorRange() {
+        return allOf(
+            greaterThan(ShardIndexingPressureMemoryManager.LOWER_OPERATING_FACTOR.get(settings)),
+            lessThanOrEqualTo(ShardIndexingPressureMemoryManager.UPPER_OPERATING_FACTOR.get(settings))
+        );
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/ShardIndexingPressureMemoryManagerTests.java b/server/src/test/java/org/opensearch/index/ShardIndexingPressureMemoryManagerTests.java
index 97ffc7150db9c..023063c7d6e03 100644
--- a/server/src/test/java/org/opensearch/index/ShardIndexingPressureMemoryManagerTests.java
+++ b/server/src/test/java/org/opensearch/index/ShardIndexingPressureMemoryManagerTests.java
@@ -11,7 +11,8 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.concurrent.TimeUnit;
diff --git a/server/src/test/java/org/opensearch/index/ShardIndexingPressureStoreTests.java b/server/src/test/java/org/opensearch/index/ShardIndexingPressureStoreTests.java
index 758345e719e6d..46f9801035ac3 100644
--- a/server/src/test/java/org/opensearch/index/ShardIndexingPressureStoreTests.java
+++ b/server/src/test/java/org/opensearch/index/ShardIndexingPressureStoreTests.java
@@ -8,12 +8,12 @@
 
 package org.opensearch.index;
 
-import org.junit.Before;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.util.Map;
 
diff --git a/server/src/test/java/org/opensearch/index/ShardIndexingPressureTests.java b/server/src/test/java/org/opensearch/index/ShardIndexingPressureTests.java
index 5722ebdf27fb5..e7600b1d4c41a 100644
--- a/server/src/test/java/org/opensearch/index/ShardIndexingPressureTests.java
+++ b/server/src/test/java/org/opensearch/index/ShardIndexingPressureTests.java
@@ -12,8 +12,9 @@
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.stats.IndexingPressurePerShardStats;
 import org.opensearch.index.stats.IndexingPressureStats;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/index/ShardIndexingPressureTrackerTests.java b/server/src/test/java/org/opensearch/index/ShardIndexingPressureTrackerTests.java
index d73a9e2f4a810..129e61316e8bc 100644
--- a/server/src/test/java/org/opensearch/index/ShardIndexingPressureTrackerTests.java
+++ b/server/src/test/java/org/opensearch/index/ShardIndexingPressureTrackerTests.java
@@ -8,12 +8,12 @@
 
 package org.opensearch.index;
 
-import org.opensearch.index.ShardIndexingPressureTracker.OperationTracker;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.ShardIndexingPressureTracker.CommonOperationTracker;
-import org.opensearch.index.ShardIndexingPressureTracker.StatsTracker;
-import org.opensearch.index.ShardIndexingPressureTracker.RejectionTracker;
+import org.opensearch.index.ShardIndexingPressureTracker.OperationTracker;
 import org.opensearch.index.ShardIndexingPressureTracker.PerformanceTracker;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.ShardIndexingPressureTracker.RejectionTracker;
+import org.opensearch.index.ShardIndexingPressureTracker.StatsTracker;
 import org.opensearch.test.OpenSearchTestCase;
 
 public class ShardIndexingPressureTrackerTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/index/analysis/AnalysisRegistryTests.java b/server/src/test/java/org/opensearch/index/analysis/AnalysisRegistryTests.java
index cbc189be491cd..2c7f11063cf0f 100644
--- a/server/src/test/java/org/opensearch/index/analysis/AnalysisRegistryTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/AnalysisRegistryTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.analysis;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockTokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.en.EnglishAnalyzer;
@@ -42,6 +42,7 @@
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.tests.analysis.MockTokenFilter;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
@@ -54,8 +55,8 @@
 import org.opensearch.indices.analysis.PreBuiltAnalyzers;
 import org.opensearch.plugins.AnalysisPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
@@ -475,13 +476,10 @@ public Map<String, AnalysisProvider<TokenFilterFactory>> getTokenFilters() {
             .build();
         IndexSettings exceptionSettings = IndexSettingsModule.newIndexSettings("index", indexSettings);
 
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> {
-                new AnalysisModule(TestEnvironment.newEnvironment(settings), singletonList(plugin)).getAnalysisRegistry()
-                    .build(exceptionSettings);
-            }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            new AnalysisModule(TestEnvironment.newEnvironment(settings), singletonList(plugin)).getAnalysisRegistry()
+                .build(exceptionSettings);
+        });
         assertEquals("Cannot use token filter [exception]", e.getMessage());
 
     }
diff --git a/server/src/test/java/org/opensearch/index/analysis/AnalysisTests.java b/server/src/test/java/org/opensearch/index/analysis/AnalysisTests.java
index d6f0cb194f222..d4b825ce09e92 100644
--- a/server/src/test/java/org/opensearch/index/analysis/AnalysisTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/AnalysisTests.java
@@ -39,14 +39,10 @@
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.BufferedWriter;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.charset.CharacterCodingException;
-import java.nio.charset.MalformedInputException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
-import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.List;
@@ -79,13 +75,10 @@ public void testParseNonExistingFile() {
         Environment env = TestEnvironment.newEnvironment(nodeSettings);
         IllegalArgumentException ex = expectThrows(
             IllegalArgumentException.class,
-            () -> Analysis.getWordList(env, nodeSettings, "foo.bar")
-        );
-        assertEquals("IOException while reading foo.bar_path: " + tempDir.resolve("foo.dict").toString(), ex.getMessage());
-        assertTrue(
-            ex.getCause().toString(),
-            ex.getCause() instanceof FileNotFoundException || ex.getCause() instanceof NoSuchFileException
+            () -> Analysis.parseWordList(env, nodeSettings, "foo.bar", s -> s)
         );
+        assertEquals("IOException while reading foo.bar_path: file not readable", ex.getMessage());
+        assertNull(ex.getCause());
     }
 
     public void testParseFalseEncodedFile() throws IOException {
@@ -99,18 +92,10 @@ public void testParseFalseEncodedFile() throws IOException {
         Environment env = TestEnvironment.newEnvironment(nodeSettings);
         IllegalArgumentException ex = expectThrows(
             IllegalArgumentException.class,
-            () -> Analysis.getWordList(env, nodeSettings, "foo.bar")
-        );
-        assertEquals(
-            "Unsupported character encoding detected while reading foo.bar_path: "
-                + tempDir.resolve("foo.dict").toString()
-                + " - files must be UTF-8 encoded",
-            ex.getMessage()
-        );
-        assertTrue(
-            ex.getCause().toString(),
-            ex.getCause() instanceof MalformedInputException || ex.getCause() instanceof CharacterCodingException
+            () -> Analysis.parseWordList(env, nodeSettings, "foo.bar", s -> s)
         );
+        assertEquals("Unsupported character encoding detected while reading foo.bar_path: files must be UTF-8 encoded", ex.getMessage());
+        assertNull(ex.getCause());
     }
 
     public void testParseWordList() throws IOException {
@@ -124,8 +109,40 @@ public void testParseWordList() throws IOException {
             writer.write('\n');
         }
         Environment env = TestEnvironment.newEnvironment(nodeSettings);
-        List<String> wordList = Analysis.getWordList(env, nodeSettings, "foo.bar");
+        List<String> wordList = Analysis.parseWordList(env, nodeSettings, "foo.bar", s -> s);
         assertEquals(Arrays.asList("hello", "world"), wordList);
+    }
+
+    public void testParseWordListError() throws IOException {
+        Path home = createTempDir();
+        Path config = home.resolve("config");
+        Files.createDirectory(config);
+        Path dict = config.resolve("foo.dict");
+        Settings nodeSettings = Settings.builder().put("foo.bar_path", dict).put(Environment.PATH_HOME_SETTING.getKey(), home).build();
+        try (BufferedWriter writer = Files.newBufferedWriter(dict, StandardCharsets.UTF_8)) {
+            writer.write("abcd");
+            writer.write('\n');
+        }
+        Environment env = TestEnvironment.newEnvironment(nodeSettings);
+        RuntimeException ex = expectThrows(RuntimeException.class, () -> Analysis.parseWordList(env, nodeSettings, "foo.bar", s -> {
+            throw new RuntimeException("Error while parsing rule = " + s);
+        }));
+        assertEquals("Line [1]: Error while parsing rule = abcd", ex.getMessage());
+    }
 
+    public void testParseWordListOutsideConfigDirError() throws IOException {
+        Path home = createTempDir();
+        Path temp = createTempDir();
+        Path dict = temp.resolve("foo.dict");
+        try (BufferedWriter writer = Files.newBufferedWriter(dict, StandardCharsets.UTF_8)) {
+            writer.write("abcd");
+            writer.write('\n');
+        }
+        Settings nodeSettings = Settings.builder().put("foo.bar_path", dict).put(Environment.PATH_HOME_SETTING.getKey(), home).build();
+        Environment env = TestEnvironment.newEnvironment(nodeSettings);
+        RuntimeException ex = expectThrows(RuntimeException.class, () -> Analysis.parseWordList(env, nodeSettings, "foo.bar", s -> {
+            throw new RuntimeException("Error while parsing rule = " + s);
+        }));
+        assertEquals("Line [1]: Invalid rule", ex.getMessage());
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/analysis/PreBuiltAnalyzerTests.java b/server/src/test/java/org/opensearch/index/analysis/PreBuiltAnalyzerTests.java
index d8e0a4ea3bc2e..d8a71df379546 100644
--- a/server/src/test/java/org/opensearch/index/analysis/PreBuiltAnalyzerTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/PreBuiltAnalyzerTests.java
@@ -36,14 +36,14 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.indices.analysis.PreBuiltAnalyzers;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/analysis/PreConfiguredTokenFilterTests.java b/server/src/test/java/org/opensearch/index/analysis/PreConfiguredTokenFilterTests.java
index 67c865be70ac5..9f997889a438a 100644
--- a/server/src/test/java/org/opensearch/index/analysis/PreConfiguredTokenFilterTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/PreConfiguredTokenFilterTests.java
@@ -38,8 +38,8 @@
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/analysis/ReloadableCustomAnalyzerTests.java b/server/src/test/java/org/opensearch/index/analysis/ReloadableCustomAnalyzerTests.java
index eb057fae66ddf..fd5271dffa290 100644
--- a/server/src/test/java/org/opensearch/index/analysis/ReloadableCustomAnalyzerTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/ReloadableCustomAnalyzerTests.java
@@ -39,9 +39,9 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.BeforeClass;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/analysis/ShingleTokenFilterFactoryTests.java b/server/src/test/java/org/opensearch/index/analysis/ShingleTokenFilterFactoryTests.java
index 110d705794d6a..41d64320cfd72 100644
--- a/server/src/test/java/org/opensearch/index/analysis/ShingleTokenFilterFactoryTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/ShingleTokenFilterFactoryTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.analysis;
 
-import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope.Scope;
 import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope;
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakScope.Scope;
 
 import org.apache.lucene.analysis.StopFilter;
 import org.apache.lucene.analysis.TokenStream;
diff --git a/server/src/test/java/org/opensearch/index/analysis/StopAnalyzerTests.java b/server/src/test/java/org/opensearch/index/analysis/StopAnalyzerTests.java
index f71edbcdcff66..68b042fa0101f 100644
--- a/server/src/test/java/org/opensearch/index/analysis/StopAnalyzerTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/StopAnalyzerTests.java
@@ -37,8 +37,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTokenStreamTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTokenStreamTestCase;
 
 import static org.opensearch.test.OpenSearchTestCase.createTestAnalysis;
 
diff --git a/server/src/test/java/org/opensearch/index/analysis/StopTokenFilterTests.java b/server/src/test/java/org/opensearch/index/analysis/StopTokenFilterTests.java
index 006c40f945ea1..7e4e0747cdd4a 100644
--- a/server/src/test/java/org/opensearch/index/analysis/StopTokenFilterTests.java
+++ b/server/src/test/java/org/opensearch/index/analysis/StopTokenFilterTests.java
@@ -38,8 +38,8 @@
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.search.suggest.analyzing.SuggestStopFilter;
 import org.apache.lucene.util.Version;
-import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.Settings.Builder;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.OpenSearchTokenStreamTestCase;
diff --git a/server/src/test/java/org/opensearch/index/cache/bitset/BitSetFilterCacheTests.java b/server/src/test/java/org/opensearch/index/cache/bitset/BitSetFilterCacheTests.java
index 1f5833ef37fb3..f3cac6abd6ced 100644
--- a/server/src/test/java/org/opensearch/index/cache/bitset/BitSetFilterCacheTests.java
+++ b/server/src/test/java/org/opensearch/index/cache/bitset/BitSetFilterCacheTests.java
@@ -52,11 +52,11 @@
 import org.apache.lucene.util.BitSet;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
diff --git a/server/src/test/java/org/opensearch/index/codec/CodecTests.java b/server/src/test/java/org/opensearch/index/codec/CodecTests.java
index 94b78da402b44..5fa8aff8c3a6c 100644
--- a/server/src/test/java/org/opensearch/index/codec/CodecTests.java
+++ b/server/src/test/java/org/opensearch/index/codec/CodecTests.java
@@ -34,8 +34,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.codecs.Codec;
-import org.apache.lucene.codecs.lucene91.Lucene91Codec;
 import org.apache.lucene.codecs.lucene90.Lucene90StoredFieldsFormat;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexWriter;
@@ -43,67 +43,157 @@
 import org.apache.lucene.index.SegmentReader;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
+import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
+import org.opensearch.index.engine.EngineConfig;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.plugins.MapperPlugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
 
+import static org.opensearch.index.engine.EngineConfig.INDEX_CODEC_COMPRESSION_LEVEL_SETTING;
 import static org.hamcrest.Matchers.instanceOf;
 
 @SuppressCodecs("*") // we test against default codec so never get a random one here!
 public class CodecTests extends OpenSearchTestCase {
 
     public void testResolveDefaultCodecs() throws Exception {
-        CodecService codecService = createCodecService();
+        CodecService codecService = createCodecService(false);
         assertThat(codecService.codec("default"), instanceOf(PerFieldMappingPostingFormatCodec.class));
-        assertThat(codecService.codec("default"), instanceOf(Lucene91Codec.class));
+        assertThat(codecService.codec("default"), instanceOf(Lucene95Codec.class));
     }
 
     public void testDefault() throws Exception {
-        Codec codec = createCodecService().codec("default");
-        assertStoredFieldsCompressionEquals(Lucene91Codec.Mode.BEST_SPEED, codec);
+        Codec codec = createCodecService(false).codec("default");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_SPEED, codec);
     }
 
     public void testBestCompression() throws Exception {
-        Codec codec = createCodecService().codec("best_compression");
-        assertStoredFieldsCompressionEquals(Lucene91Codec.Mode.BEST_COMPRESSION, codec);
+        Codec codec = createCodecService(false).codec("best_compression");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_COMPRESSION, codec);
+    }
+
+    public void testLZ4() throws Exception {
+        Codec codec = createCodecService(false).codec("lz4");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_SPEED, codec);
+        assert codec instanceof PerFieldMappingPostingFormatCodec;
+    }
+
+    public void testZlib() throws Exception {
+        Codec codec = createCodecService(false).codec("zlib");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_COMPRESSION, codec);
+        assert codec instanceof PerFieldMappingPostingFormatCodec;
+    }
+
+    public void testBestCompressionWithCompressionLevel() {
+        final Settings settings = Settings.builder()
+            .put(INDEX_CODEC_COMPRESSION_LEVEL_SETTING.getKey(), randomIntBetween(1, 6))
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), randomFrom(CodecService.DEFAULT_CODEC, CodecService.BEST_COMPRESSION_CODEC))
+            .build();
+        final IndexScopedSettings indexScopedSettings = new IndexScopedSettings(settings, IndexScopedSettings.BUILT_IN_INDEX_SETTINGS);
+
+        final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> indexScopedSettings.validate(settings, true));
+        assertTrue(e.getMessage().startsWith("Compression level cannot be set"));
+    }
+
+    public void testLuceneCodecsWithCompressionLevel() {
+        String codecName = randomFrom(Codec.availableCodecs());
+        Codec codec = Codec.forName(codecName);
+
+        final Settings settings = Settings.builder()
+            .put(INDEX_CODEC_COMPRESSION_LEVEL_SETTING.getKey(), randomIntBetween(1, 6))
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), codecName)
+            .build();
+        final IndexScopedSettings indexScopedSettings = new IndexScopedSettings(settings, IndexScopedSettings.BUILT_IN_INDEX_SETTINGS);
+
+        if (!(codec instanceof CodecSettings && ((CodecSettings) codec).supports(INDEX_CODEC_COMPRESSION_LEVEL_SETTING))) {
+            final IllegalArgumentException e = expectThrows(
+                IllegalArgumentException.class,
+                () -> indexScopedSettings.validate(settings, true)
+            );
+            assertTrue(e.getMessage().startsWith("Compression level cannot be set"));
+        }
+    }
+
+    public void testDefaultMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("default");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_SPEED, codec);
+    }
+
+    public void testBestCompressionMapperServiceNull() throws Exception {
+        Codec codec = createCodecService(true).codec("best_compression");
+        assertStoredFieldsCompressionEquals(Lucene95Codec.Mode.BEST_COMPRESSION, codec);
+    }
+
+    public void testExceptionCodecNull() {
+        assertThrows(IllegalArgumentException.class, () -> createCodecService(true).codec(null));
+    }
+
+    public void testExceptionIndexSettingsNull() {
+        assertThrows(AssertionError.class, () -> new CodecService(null, null, LogManager.getLogger("test")));
+    }
+
+    public void testCodecServiceWithNullMapperService() {
+        Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("_na", nodeSettings);
+        CodecService codecService = new CodecService(null, indexSettings, LogManager.getLogger("test"));
+        assert codecService.codec("default") instanceof Lucene95Codec;
+        assert codecService.codec("best_compression") instanceof Lucene95Codec;
+    }
+
+    public void testCodecServiceWithOnlyMapperService() throws IOException {
+        int randomCompressionLevel = randomIntBetween(1, 6);
+        Settings nodeSettings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+            .put("index.codec.compression_level", randomCompressionLevel)
+            .build();
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("_na", nodeSettings);
+        CodecService codecService = new CodecService(
+            getMapperService(indexSettings, nodeSettings),
+            indexSettings,
+            LogManager.getLogger("test")
+        );
+        assert codecService.codec("default") instanceof PerFieldMappingPostingFormatCodec;
+        assert codecService.codec("best_compression") instanceof PerFieldMappingPostingFormatCodec;
     }
 
     // write some docs with it, inspect .si to see this was the used compression
-    private void assertStoredFieldsCompressionEquals(Lucene91Codec.Mode expected, Codec actual) throws Exception {
-        Directory dir = newDirectory();
-        IndexWriterConfig iwc = newIndexWriterConfig(null);
-        iwc.setCodec(actual);
-        IndexWriter iw = new IndexWriter(dir, iwc);
-        iw.addDocument(new Document());
-        iw.commit();
-        iw.close();
-        DirectoryReader ir = DirectoryReader.open(dir);
-        SegmentReader sr = (SegmentReader) ir.leaves().get(0).reader();
+    private void assertStoredFieldsCompressionEquals(Lucene95Codec.Mode expected, Codec actual) throws Exception {
+        SegmentReader sr = getSegmentReader(actual);
         String v = sr.getSegmentInfo().info.getAttribute(Lucene90StoredFieldsFormat.MODE_KEY);
         assertNotNull(v);
-        assertEquals(expected, Lucene91Codec.Mode.valueOf(v));
-        ir.close();
-        dir.close();
+        assertEquals(expected, Lucene95Codec.Mode.valueOf(v));
     }
 
-    private CodecService createCodecService() throws IOException {
+    private CodecService createCodecService(boolean isMapperServiceNull) throws IOException {
         Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
-        IndexSettings settings = IndexSettingsModule.newIndexSettings("_na", nodeSettings);
-        SimilarityService similarityService = new SimilarityService(settings, null, Collections.emptyMap());
-        IndexAnalyzers indexAnalyzers = createTestAnalysis(settings, nodeSettings).indexAnalyzers;
+        if (isMapperServiceNull) {
+            return new CodecService(null, IndexSettingsModule.newIndexSettings("_na", nodeSettings), LogManager.getLogger("test"));
+        }
+        return buildCodecService(nodeSettings);
+    }
+
+    private CodecService buildCodecService(Settings nodeSettings) throws IOException {
+
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("_na", nodeSettings);
+        MapperService mapperService = getMapperService(indexSettings, nodeSettings);
+        return new CodecService(mapperService, indexSettings, LogManager.getLogger("test"));
+    }
+
+    private MapperService getMapperService(IndexSettings indexSettings, Settings nodeSettings) throws IOException {
+        SimilarityService similarityService = new SimilarityService(indexSettings, null, Collections.emptyMap());
+        IndexAnalyzers indexAnalyzers = createTestAnalysis(indexSettings, nodeSettings).indexAnalyzers;
         MapperRegistry mapperRegistry = new MapperRegistry(Collections.emptyMap(), Collections.emptyMap(), MapperPlugin.NOOP_FIELD_FILTER);
-        MapperService service = new MapperService(
-            settings,
+        return new MapperService(
+            indexSettings,
             indexAnalyzers,
             xContentRegistry(),
             similarityService,
@@ -112,7 +202,21 @@ private CodecService createCodecService() throws IOException {
             () -> false,
             null
         );
-        return new CodecService(service, LogManager.getLogger("test"));
+    }
+
+    private SegmentReader getSegmentReader(Codec codec) throws IOException {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig(null);
+        iwc.setCodec(codec);
+        IndexWriter iw = new IndexWriter(dir, iwc);
+        iw.addDocument(new Document());
+        iw.commit();
+        iw.close();
+        DirectoryReader ir = DirectoryReader.open(dir);
+        SegmentReader sr = (SegmentReader) ir.leaves().get(0).reader();
+        ir.close();
+        dir.close();
+        return sr;
     }
 
 }
diff --git a/server/src/test/java/org/opensearch/index/engine/CombinedDeletionPolicyTests.java b/server/src/test/java/org/opensearch/index/engine/CombinedDeletionPolicyTests.java
index dac6fa90bd917..dd469644709ec 100644
--- a/server/src/test/java/org/opensearch/index/engine/CombinedDeletionPolicyTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/CombinedDeletionPolicyTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.engine;
 
-import com.carrotsearch.hppc.LongArrayList;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.store.Directory;
 import org.opensearch.index.seqno.RetentionLeases;
@@ -74,7 +73,7 @@ public void testKeepCommitsAfterGlobalCheckpoint() throws Exception {
         TranslogDeletionPolicy translogPolicy = createTranslogDeletionPolicy();
         CombinedDeletionPolicy indexPolicy = newCombinedDeletionPolicy(translogPolicy, softDeletesPolicy, globalCheckpoint);
 
-        final LongArrayList maxSeqNoList = new LongArrayList();
+        final List<Long> maxSeqNoList = new ArrayList<>();
         final List<IndexCommit> commitList = new ArrayList<>();
         int totalCommits = between(2, 20);
         long lastMaxSeqNo = 0;
diff --git a/server/src/test/java/org/opensearch/index/engine/CompletionStatsCacheTests.java b/server/src/test/java/org/opensearch/index/engine/CompletionStatsCacheTests.java
index 66b066b907100..b746d0ba8a56d 100644
--- a/server/src/test/java/org/opensearch/index/engine/CompletionStatsCacheTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/CompletionStatsCacheTests.java
@@ -32,7 +32,7 @@
 package org.opensearch.index.engine;
 
 import org.apache.lucene.codecs.PostingsFormat;
-import org.apache.lucene.codecs.lucene91.Lucene91Codec;
+import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexWriter;
@@ -43,7 +43,7 @@
 import org.apache.lucene.search.suggest.document.SuggestField;
 import org.apache.lucene.store.Directory;
 import org.opensearch.OpenSearchException;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.search.suggest.completion.CompletionStats;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -59,9 +59,9 @@ public class CompletionStatsCacheTests extends OpenSearchTestCase {
 
     public void testExceptionsAreNotCached() {
         final AtomicInteger openCount = new AtomicInteger();
-        final CompletionStatsCache completionStatsCache = new CompletionStatsCache(
-            () -> { throw new OpenSearchException("simulated " + openCount.incrementAndGet()); }
-        );
+        final CompletionStatsCache completionStatsCache = new CompletionStatsCache(() -> {
+            throw new OpenSearchException("simulated " + openCount.incrementAndGet());
+        });
 
         assertThat(expectThrows(OpenSearchException.class, completionStatsCache::get).getMessage(), equalTo("simulated 1"));
         assertThat(expectThrows(OpenSearchException.class, completionStatsCache::get).getMessage(), equalTo("simulated 2"));
@@ -70,7 +70,7 @@ public void testExceptionsAreNotCached() {
     public void testCompletionStatsCache() throws IOException, InterruptedException {
         final IndexWriterConfig indexWriterConfig = newIndexWriterConfig();
         final PostingsFormat postingsFormat = new Completion90PostingsFormat();
-        indexWriterConfig.setCodec(new Lucene91Codec() {
+        indexWriterConfig.setCodec(new Lucene95Codec() {
             @Override
             public PostingsFormat getPostingsFormatForField(String field) {
                 return postingsFormat; // all fields are suggest fields
diff --git a/server/src/test/java/org/opensearch/index/engine/EngineConfigFactoryTests.java b/server/src/test/java/org/opensearch/index/engine/EngineConfigFactoryTests.java
index 8030619500278..bf9a86cff8b76 100644
--- a/server/src/test/java/org/opensearch/index/engine/EngineConfigFactoryTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/EngineConfigFactoryTests.java
@@ -16,6 +16,7 @@
 import org.opensearch.index.codec.CodecService;
 import org.opensearch.index.codec.CodecServiceFactory;
 import org.opensearch.index.seqno.RetentionLeases;
+import org.opensearch.index.translog.InternalTranslogFactory;
 import org.opensearch.index.translog.TranslogDeletionPolicy;
 import org.opensearch.index.translog.TranslogDeletionPolicyFactory;
 import org.opensearch.index.translog.TranslogReader;
@@ -65,6 +66,10 @@ public void testCreateEngineConfigFromFactory() {
             null,
             () -> new RetentionLeases(0, 0, Collections.emptyList()),
             null,
+            null,
+            false,
+            () -> Boolean.TRUE,
+            new InternalTranslogFactory(),
             null
         );
 
@@ -141,6 +146,10 @@ public void testCreateCodecServiceFromFactory() {
             null,
             () -> new RetentionLeases(0, 0, Collections.emptyList()),
             null,
+            null,
+            false,
+            () -> Boolean.TRUE,
+            new InternalTranslogFactory(),
             null
         );
         assertNotNull(config.getCodec());
@@ -169,7 +178,7 @@ public Optional<EngineFactory> getEngineFactory(final IndexSettings indexSetting
 
         @Override
         public Optional<CodecService> getCustomCodecService(IndexSettings indexSettings) {
-            return Optional.of(new CodecService(null, LogManager.getLogger(getClass())));
+            return Optional.of(new CodecService(null, indexSettings, LogManager.getLogger(getClass())));
         }
 
         @Override
@@ -186,7 +195,7 @@ public Optional<EngineFactory> getEngineFactory(final IndexSettings indexSetting
 
         @Override
         public Optional<CodecService> getCustomCodecService(IndexSettings indexSettings) {
-            return Optional.of(new CodecService(null, LogManager.getLogger(getClass())));
+            return Optional.of(new CodecService(null, indexSettings, LogManager.getLogger(getClass())));
         }
     }
 
@@ -198,7 +207,9 @@ public Optional<EngineFactory> getEngineFactory(final IndexSettings indexSetting
 
         @Override
         public Optional<CodecServiceFactory> getCustomCodecServiceFactory(IndexSettings indexSettings) {
-            return Optional.of(config -> new CodecService(config.getMapperService(), LogManager.getLogger(getClass())));
+            return Optional.of(
+                config -> new CodecService(config.getMapperService(), config.getIndexSettings(), LogManager.getLogger(getClass()))
+            );
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/index/engine/EngineConfigTests.java b/server/src/test/java/org/opensearch/index/engine/EngineConfigTests.java
new file mode 100644
index 0000000000000..9197b959a54f1
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/engine/EngineConfigTests.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.seqno.RetentionLeases;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class EngineConfigTests extends OpenSearchTestCase {
+
+    private IndexSettings defaultIndexSettings;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        final IndexMetadata defaultIndexMetadata = IndexMetadata.builder("test")
+            .settings(settings(Version.CURRENT))
+            .numberOfShards(1)
+            .numberOfReplicas(1)
+            .build();
+        defaultIndexSettings = IndexSettingsModule.newIndexSettings("test", defaultIndexMetadata.getSettings());
+    }
+
+    public void testEngineConfig_DefaultValueForReadOnlyEngine() {
+        EngineConfig config = new EngineConfig.Builder().indexSettings(defaultIndexSettings)
+            .retentionLeasesSupplier(() -> RetentionLeases.EMPTY)
+            .build();
+        assertFalse(config.isReadOnlyReplica());
+    }
+
+    public void testEngineConfig_ReadOnlyEngineWithSegRepDisabled() {
+        expectThrows(IllegalArgumentException.class, () -> createReadOnlyEngine(defaultIndexSettings));
+    }
+
+    public void testEngineConfig_ReadOnlyEngineWithSegRepEnabled() {
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(
+            "test",
+            Settings.builder()
+                .put(defaultIndexSettings.getSettings())
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .build()
+        );
+        EngineConfig engineConfig = createReadOnlyEngine(indexSettings);
+        assertTrue(engineConfig.isReadOnlyReplica());
+    }
+
+    private EngineConfig createReadOnlyEngine(IndexSettings indexSettings) {
+        return new EngineConfig.Builder().indexSettings(indexSettings)
+            .retentionLeasesSupplier(() -> RetentionLeases.EMPTY)
+            .readOnlyReplica(true)
+            .build();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java b/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
index 361013149578e..a03b8ac25a18c 100644
--- a/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
@@ -32,15 +32,17 @@
 
 package org.opensearch.index.engine;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.appender.AbstractAppender;
 import org.apache.logging.log4j.core.filter.RegexFilter;
+import org.apache.lucene.codecs.LiveDocsFormat;
 import org.apache.lucene.document.Field;
+import org.apache.lucene.document.KeywordField;
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.StoredField;
@@ -51,6 +53,7 @@
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.index.IndexableFieldType;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.LiveIndexWriterConfig;
@@ -76,16 +79,13 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.Lock;
+import org.apache.lucene.tests.mockfile.ExtrasFS;
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
-import org.apache.lucene.util.SetOnce;
-import org.hamcrest.MatcherAssert;
-import org.hamcrest.Matchers;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.TransportActions;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -96,11 +96,9 @@
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.logging.Loggers;
@@ -111,17 +109,24 @@
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver;
 import org.opensearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndSeqNo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.engine.Engine.IndexResult;
 import org.opensearch.index.fieldvisitor.FieldsVisitor;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.ParseContext;
@@ -137,19 +142,24 @@
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardUtils;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.DefaultTranslogDeletionPolicy;
+import org.opensearch.index.translog.LocalTranslog;
 import org.opensearch.index.translog.SnapshotMatchers;
 import org.opensearch.index.translog.TestTranslog;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
 import org.opensearch.index.translog.TranslogDeletionPolicyFactory;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.index.translog.TranslogException;
+import org.opensearch.index.translog.listener.TranslogEventListener;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.threadpool.ThreadPool;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Assert;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -159,6 +169,7 @@
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -189,6 +200,15 @@
 import java.util.stream.LongStream;
 
 import static java.util.Collections.shuffle;
+import static org.opensearch.index.engine.Engine.Operation.Origin.LOCAL_RESET;
+import static org.opensearch.index.engine.Engine.Operation.Origin.LOCAL_TRANSLOG_RECOVERY;
+import static org.opensearch.index.engine.Engine.Operation.Origin.PEER_RECOVERY;
+import static org.opensearch.index.engine.Engine.Operation.Origin.PRIMARY;
+import static org.opensearch.index.engine.Engine.Operation.Origin.REPLICA;
+import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
+import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
+import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
+import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.sameInstance;
 import static org.hamcrest.Matchers.contains;
@@ -211,18 +231,10 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-import static org.opensearch.index.engine.Engine.Operation.Origin.LOCAL_RESET;
-import static org.opensearch.index.engine.Engine.Operation.Origin.LOCAL_TRANSLOG_RECOVERY;
-import static org.opensearch.index.engine.Engine.Operation.Origin.PEER_RECOVERY;
-import static org.opensearch.index.engine.Engine.Operation.Origin.PRIMARY;
-import static org.opensearch.index.engine.Engine.Operation.Origin.REPLICA;
-import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
-import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
-import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
-import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
 
 public class InternalEngineTests extends EngineTestCase {
 
@@ -381,7 +393,7 @@ public void testSegmentsWithMergeFlag() throws Exception {
     }
 
     public void testSegmentsWithIndexSort() throws Exception {
-        Sort indexSort = new Sort(new SortedSetSortField("_type", false));
+        Sort indexSort = new Sort(new SortedSetSortField("field", false));
         try (
             Store store = createStore();
             Engine engine = createEngine(defaultSettings, store, createTempDir(), NoMergePolicy.INSTANCE, null, null, null, indexSort, null)
@@ -422,15 +434,15 @@ public void testSegmentsStatsIncludingFileSizes() throws Exception {
 
             SegmentsStats stats = engine.segmentsStats(true, false);
             assertThat(stats.getFileSizes().size(), greaterThan(0));
-            assertThat(() -> stats.getFileSizes().valuesIt(), everyItem(greaterThan(0L)));
+            assertThat(() -> stats.getFileSizes().values().iterator(), everyItem(greaterThan(0L)));
 
-            ObjectObjectCursor<String, Long> firstEntry = stats.getFileSizes().iterator().next();
+            Map.Entry<String, Long> firstEntry = stats.getFileSizes().entrySet().iterator().next();
 
             ParsedDocument doc2 = testParsedDocument("2", null, testDocumentWithTextField(), B_2, null);
             engine.index(indexForDoc(doc2));
             engine.refresh("test");
 
-            assertThat(engine.segmentsStats(true, false).getFileSizes().get(firstEntry.key), greaterThan(firstEntry.value));
+            assertThat(engine.segmentsStats(true, false).getFileSizes().get(firstEntry.getKey()), greaterThan(firstEntry.getValue()));
         }
     }
 
@@ -494,6 +506,249 @@ public void testSegments() throws Exception {
         }
     }
 
+    public void testMergeSegmentsOnCommitIsDisabled() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        final Settings.Builder settings = Settings.builder()
+            .put(defaultSettings.getSettings())
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED.getKey(), false);
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        try (
+            Store store = createStore();
+            InternalEngine engine = createEngine(
+                config(indexSettings, store, createTempDir(), NoMergePolicy.INSTANCE, null, null, globalCheckpoint::get)
+            )
+        ) {
+            assertThat(engine.segments(false), empty());
+            int numDocsFirstSegment = randomIntBetween(5, 50);
+            Set<String> liveDocsFirstSegment = new HashSet<>();
+            for (int i = 0; i < numDocsFirstSegment; i++) {
+                String id = Integer.toString(i);
+                ParsedDocument doc = testParsedDocument(id, null, testDocument(), B_1, null);
+                engine.index(indexForDoc(doc));
+                liveDocsFirstSegment.add(id);
+            }
+            engine.refresh("test");
+            List<Segment> segments = engine.segments(randomBoolean());
+            assertThat(segments, hasSize(1));
+            assertThat(segments.get(0).getNumDocs(), equalTo(liveDocsFirstSegment.size()));
+            assertThat(segments.get(0).getDeletedDocs(), equalTo(0));
+            assertFalse(segments.get(0).committed);
+            int deletes = 0;
+            int updates = 0;
+            int appends = 0;
+            int iterations = scaledRandomIntBetween(1, 50);
+            for (int i = 0; i < iterations && liveDocsFirstSegment.isEmpty() == false; i++) {
+                String idToUpdate = randomFrom(liveDocsFirstSegment);
+                liveDocsFirstSegment.remove(idToUpdate);
+                ParsedDocument doc = testParsedDocument(idToUpdate, null, testDocument(), B_1, null);
+                if (randomBoolean()) {
+                    engine.delete(new Engine.Delete(doc.id(), newUid(doc), primaryTerm.get()));
+                    deletes++;
+                } else {
+                    engine.index(indexForDoc(doc));
+                    updates++;
+                }
+                if (randomBoolean()) {
+                    engine.index(indexForDoc(testParsedDocument(UUIDs.randomBase64UUID(), null, testDocument(), B_1, null)));
+                    appends++;
+                }
+            }
+
+            boolean committed = randomBoolean();
+            if (committed) {
+                engine.flush();
+            }
+
+            engine.refresh("test");
+            segments = engine.segments(randomBoolean());
+
+            assertThat(segments, hasSize(2));
+            assertThat(segments, hasSize(2));
+            assertThat(segments.get(0).getNumDocs(), equalTo(liveDocsFirstSegment.size()));
+            assertThat(segments.get(0).getDeletedDocs(), equalTo(updates + deletes));
+            assertThat(segments.get(0).committed, equalTo(committed));
+
+            assertThat(segments.get(1).getNumDocs(), equalTo(updates + appends));
+            assertThat(segments.get(1).getDeletedDocs(), equalTo(deletes)); // delete tombstones
+            assertThat(segments.get(1).committed, equalTo(committed));
+        }
+    }
+
+    public void testMergeSegmentsOnCommit() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        final Settings.Builder settings = Settings.builder()
+            .put(defaultSettings.getSettings())
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME.getKey(), TimeValue.timeValueMillis(5000))
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_POLICY.getKey(), "merge-on-flush");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        try (
+            Store store = createStore();
+            InternalEngine engine = createEngine(
+                config(indexSettings, store, createTempDir(), NoMergePolicy.INSTANCE, null, null, globalCheckpoint::get)
+            )
+        ) {
+            assertThat(engine.segments(false), empty());
+            int numDocsFirstSegment = randomIntBetween(5, 50);
+            Set<String> liveDocsFirstSegment = new HashSet<>();
+            for (int i = 0; i < numDocsFirstSegment; i++) {
+                String id = Integer.toString(i);
+                ParsedDocument doc = testParsedDocument(id, null, testDocument(), B_1, null);
+                engine.index(indexForDoc(doc));
+                liveDocsFirstSegment.add(id);
+            }
+            engine.refresh("test");
+            List<Segment> segments = engine.segments(randomBoolean());
+            assertThat(segments, hasSize(1));
+            assertThat(segments.get(0).getNumDocs(), equalTo(liveDocsFirstSegment.size()));
+            assertThat(segments.get(0).getDeletedDocs(), equalTo(0));
+            assertFalse(segments.get(0).committed);
+            int deletes = 0;
+            int updates = 0;
+            int appends = 0;
+            int iterations = scaledRandomIntBetween(1, 50);
+            for (int i = 0; i < iterations && liveDocsFirstSegment.isEmpty() == false; i++) {
+                String idToUpdate = randomFrom(liveDocsFirstSegment);
+                liveDocsFirstSegment.remove(idToUpdate);
+                ParsedDocument doc = testParsedDocument(idToUpdate, null, testDocument(), B_1, null);
+                if (randomBoolean()) {
+                    engine.delete(new Engine.Delete(doc.id(), newUid(doc), primaryTerm.get()));
+                    deletes++;
+                } else {
+                    engine.index(indexForDoc(doc));
+                    updates++;
+                }
+                if (randomBoolean()) {
+                    engine.index(indexForDoc(testParsedDocument(UUIDs.randomBase64UUID(), null, testDocument(), B_1, null)));
+                    appends++;
+                }
+            }
+
+            boolean committed = randomBoolean();
+            if (committed) {
+                engine.flush();
+            }
+
+            engine.refresh("test");
+            segments = engine.segments(randomBoolean());
+
+            // All segments have to be merged into one
+            assertThat(segments, hasSize(1));
+            assertThat(segments.get(0).getNumDocs(), equalTo(numDocsFirstSegment + appends - deletes));
+            assertThat(segments.get(0).getDeletedDocs(), equalTo(0));
+            assertThat(segments.get(0).committed, equalTo(committed));
+        }
+    }
+
+    public void testMergeSegmentsOnCommitDefault() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        final Settings.Builder settings = Settings.builder().put(defaultSettings.getSettings());
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        final TieredMergePolicy mergePolicy = new TieredMergePolicy();
+        mergePolicy.setSegmentsPerTier(2);
+
+        try (
+            Store store = createStore();
+            InternalEngine engine = createEngine(
+                config(indexSettings, store, createTempDir(), mergePolicy, null, null, globalCheckpoint::get)
+            )
+        ) {
+            List<Segment> segments = engine.segments(true);
+            assertThat(segments.isEmpty(), equalTo(true));
+
+            ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), B_1, null);
+            engine.index(indexForDoc(doc));
+            engine.refresh("test");
+
+            segments = engine.segments(true);
+            assertThat(segments.size(), equalTo(1));
+
+            ParsedDocument doc2 = testParsedDocument("2", null, testDocumentWithTextField(), B_2, null);
+            engine.index(indexForDoc(doc2));
+            engine.refresh("test");
+            ParsedDocument doc3 = testParsedDocument("3", null, testDocumentWithTextField(), B_3, null);
+            engine.index(indexForDoc(doc3));
+            engine.refresh("test");
+
+            segments = engine.segments(true);
+            assertThat(segments.size(), equalTo(2));
+        }
+    }
+
+    // this test writes documents to the engine while concurrently flushing/commit
+    public void testConcurrentMergeSegmentsOnCommit() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        final Settings.Builder settings = Settings.builder()
+            .put(defaultSettings.getSettings())
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_MAX_FULL_FLUSH_MERGE_WAIT_TIME.getKey(), TimeValue.timeValueMillis(5000))
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_POLICY.getKey(), "merge-on-flush");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        try (
+            Store store = createStore();
+            InternalEngine engine = createEngine(
+                config(indexSettings, store, createTempDir(), NoMergePolicy.INSTANCE, null, null, globalCheckpoint::get)
+            )
+        ) {
+            final int numIndexingThreads = scaledRandomIntBetween(3, 8);
+            final int numDocsPerThread = randomIntBetween(500, 1000);
+            final CyclicBarrier barrier = new CyclicBarrier(numIndexingThreads + 1);
+            final List<Thread> indexingThreads = new ArrayList<>();
+            final CountDownLatch doneLatch = new CountDownLatch(numIndexingThreads);
+            // create N indexing threads to index documents simultaneously
+            for (int threadNum = 0; threadNum < numIndexingThreads; threadNum++) {
+                final int threadIdx = threadNum;
+                Thread indexingThread = new Thread(() -> {
+                    try {
+                        barrier.await(); // wait for all threads to start at the same time
+                        // index random number of docs
+                        for (int i = 0; i < numDocsPerThread; i++) {
+                            final String id = "thread" + threadIdx + "#" + i;
+                            ParsedDocument doc = testParsedDocument(id, null, testDocument(), B_1, null);
+                            engine.index(indexForDoc(doc));
+                        }
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    } finally {
+                        doneLatch.countDown();
+                    }
+
+                });
+                indexingThreads.add(indexingThread);
+            }
+
+            // start the indexing threads
+            for (Thread thread : indexingThreads) {
+                thread.start();
+            }
+            barrier.await(); // wait for indexing threads to all be ready to start
+            assertThat(doneLatch.await(10, TimeUnit.SECONDS), is(true));
+
+            boolean committed = randomBoolean();
+            if (committed) {
+                engine.flush();
+            }
+
+            engine.refresh("test");
+            List<Segment> segments = engine.segments(randomBoolean());
+
+            // All segments have to be merged into one
+            assertThat(segments, hasSize(1));
+            assertThat(segments.get(0).getNumDocs(), equalTo(numIndexingThreads * numDocsPerThread));
+            assertThat(segments.get(0).committed, equalTo(committed));
+        }
+    }
+
     public void testCommitStats() throws IOException {
         final AtomicLong maxSeqNo = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
         final AtomicLong localCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
@@ -551,20 +806,20 @@ public long getProcessedCheckpoint() {
     }
 
     public void testFlushIsDisabledDuringTranslogRecovery() throws IOException {
-        engine.ensureCanFlush(); // recovered already
+        engine.translogManager().ensureCanFlush(); // recovered already
         ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), SOURCE, null);
         engine.index(indexForDoc(doc));
         engine.close();
 
         engine = new InternalEngine(engine.config());
-        expectThrows(IllegalStateException.class, engine::ensureCanFlush);
+        expectThrows(IllegalStateException.class, engine.translogManager()::ensureCanFlush);
         expectThrows(IllegalStateException.class, () -> engine.flush(true, true));
         if (randomBoolean()) {
-            engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
         } else {
-            engine.skipTranslogRecovery();
+            engine.translogManager().skipTranslogRecovery();
         }
-        engine.ensureCanFlush(); // ready
+        engine.translogManager().ensureCanFlush(); // ready
         doc = testParsedDocument("2", null, testDocumentWithTextField(), SOURCE, null);
         engine.index(indexForDoc(doc));
         engine.flush();
@@ -615,8 +870,10 @@ public void testTranslogMultipleOperationsSameDocument() throws IOException {
         } finally {
             IOUtils.close(engine);
         }
-        try (Engine recoveringEngine = new InternalEngine(engine.config())) {
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+        try (InternalEngine recoveringEngine = new InternalEngine(engine.config())) {
+            TranslogHandler translogHandler = createTranslogHandler(engine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             recoveringEngine.refresh("test");
             try (Engine.Searcher searcher = recoveringEngine.acquireSearcher("test")) {
                 final TotalHitCountCollector collector = new TotalHitCountCollector();
@@ -640,7 +897,7 @@ public void testTranslogRecoveryDoesNotReplayIntoTranslog() throws IOException {
             IOUtils.close(initialEngine);
         }
 
-        Engine recoveringEngine = null;
+        InternalEngine recoveringEngine = null;
         try {
             final AtomicBoolean committed = new AtomicBoolean();
             recoveringEngine = new InternalEngine(initialEngine.config()) {
@@ -651,8 +908,10 @@ protected void commitIndexWriter(IndexWriter writer, Translog translog) throws I
                     super.commitIndexWriter(writer, translog);
                 }
             };
-            assertThat(getTranslog(recoveringEngine).stats().getUncommittedOperations(), equalTo(docs));
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            assertThat(recoveringEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(docs));
+            TranslogHandler translogHandler = createTranslogHandler(initialEngine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             assertTrue(committed.get());
         } finally {
             IOUtils.close(recoveringEngine);
@@ -664,7 +923,7 @@ public void testTranslogRecoveryWithMultipleGenerations() throws IOException {
         final List<Long> seqNos = LongStream.range(0, docs).boxed().collect(Collectors.toList());
         Randomness.shuffle(seqNos);
         Engine initialEngine = null;
-        Engine recoveringEngine = null;
+        InternalEngine recoveringEngine = null;
         Store store = createStore();
         final AtomicInteger counter = new AtomicInteger();
         try {
@@ -686,7 +945,9 @@ public void testTranslogRecoveryWithMultipleGenerations() throws IOException {
             }
             initialEngine.close();
             recoveringEngine = new InternalEngine(initialEngine.config());
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            TranslogHandler translogHandler = createTranslogHandler(initialEngine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             recoveringEngine.refresh("test");
             try (Engine.Searcher searcher = recoveringEngine.acquireSearcher("test")) {
                 TopDocs topDocs = searcher.search(new MatchAllDocsQuery(), docs);
@@ -709,23 +970,25 @@ public void testRecoveryFromTranslogUpToSeqNo() throws IOException {
                     final ParsedDocument doc = testParsedDocument(id, null, testDocumentWithTextField(), SOURCE, null);
                     engine.index(indexForDoc(doc));
                     if (rarely()) {
-                        engine.rollTranslogGeneration();
+                        engine.translogManager().rollTranslogGeneration();
                     } else if (rarely()) {
                         engine.flush(randomBoolean(), true);
                     }
                 }
                 maxSeqNo = engine.getLocalCheckpointTracker().getMaxSeqNo();
                 globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getProcessedLocalCheckpoint()));
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
             }
             try (InternalEngine engine = new InternalEngine(config)) {
-                engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), engine);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 assertThat(engine.getProcessedLocalCheckpoint(), equalTo(maxSeqNo));
                 assertThat(engine.getLocalCheckpointTracker().getMaxSeqNo(), equalTo(maxSeqNo));
             }
             try (InternalEngine engine = new InternalEngine(config)) {
                 long upToSeqNo = randomLongBetween(globalCheckpoint.get(), maxSeqNo);
-                engine.recoverFromTranslog(translogHandler, upToSeqNo);
+                TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), engine);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), upToSeqNo);
                 assertThat(engine.getProcessedLocalCheckpoint(), equalTo(upToSeqNo));
                 assertThat(engine.getLocalCheckpointTracker().getMaxSeqNo(), equalTo(upToSeqNo));
             }
@@ -1040,26 +1303,39 @@ public void testCommitAdvancesMinTranslogForRecovery() throws IOException {
         engine.index(indexForDoc(doc));
         boolean inSync = randomBoolean();
         if (inSync) {
-            engine.syncTranslog(); // to advance persisted local checkpoint
+            engine.translogManager().syncTranslog(); // to advance persisted local checkpoint
             globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
         }
 
         engine.flush();
-        assertThat(engine.getTranslog().currentFileGeneration(), equalTo(3L));
-        assertThat(engine.getTranslog().getMinFileGeneration(), equalTo(inSync ? 3L : 2L));
+        engine.ensureOpen();
+        assertThat(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration(), equalTo(3L));
+        assertThat(
+            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration(),
+            equalTo(inSync ? 3L : 2L)
+        );
 
         engine.flush();
-        assertThat(engine.getTranslog().currentFileGeneration(), equalTo(3L));
-        assertThat(engine.getTranslog().getMinFileGeneration(), equalTo(inSync ? 3L : 2L));
+        engine.ensureOpen();
+        assertThat(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration(), equalTo(3L));
+        assertThat(
+            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration(),
+            equalTo(inSync ? 3L : 2L)
+        );
 
         engine.flush(true, true);
-        assertThat(engine.getTranslog().currentFileGeneration(), equalTo(3L));
-        assertThat(engine.getTranslog().getMinFileGeneration(), equalTo(inSync ? 3L : 2L));
+        engine.ensureOpen();
+        assertThat(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration(), equalTo(3L));
+        assertThat(
+            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration(),
+            equalTo(inSync ? 3L : 2L)
+        );
 
         globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
         engine.flush(true, true);
-        assertThat(engine.getTranslog().currentFileGeneration(), equalTo(3L));
-        assertThat(engine.getTranslog().getMinFileGeneration(), equalTo(3L));
+        engine.ensureOpen();
+        assertThat(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration(), equalTo(3L));
+        assertThat(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration(), equalTo(3L));
     }
 
     public void testSyncTranslogConcurrently() throws Exception {
@@ -1072,7 +1348,7 @@ public void testSyncTranslogConcurrently() throws Exception {
         applyOperations(engine, ops);
         engine.flush(true, true);
         final CheckedRunnable<IOException> checker = () -> {
-            assertThat(engine.getTranslogStats().getUncommittedOperations(), equalTo(0));
+            assertThat(engine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(0));
             assertThat(engine.getLastSyncedGlobalCheckpoint(), equalTo(globalCheckpoint.get()));
             try (GatedCloseable<IndexCommit> wrappedSafeCommit = engine.acquireSafeIndexCommit()) {
                 SequenceNumbers.CommitInfo commitInfo = SequenceNumbers.loadSeqNoInfoFromLuceneCommit(
@@ -1088,7 +1364,7 @@ public void testSyncTranslogConcurrently() throws Exception {
             threads[i] = new Thread(() -> {
                 phaser.arriveAndAwaitAdvance();
                 try {
-                    engine.syncTranslog();
+                    engine.translogManager().syncTranslog();
                     checker.run();
                 } catch (IOException e) {
                     throw new AssertionError(e);
@@ -1143,7 +1419,7 @@ public void testSyncedFlushSurvivesEngineRestart() throws IOException {
             store.associateIndexWithNewTranslog(translogUUID);
         }
         engine = new InternalEngine(config);
-        engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+        engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
         assertEquals(engine.getLastCommittedSegmentInfos().getUserData().get(Engine.SYNC_COMMIT_ID), syncId);
     }
 
@@ -1177,7 +1453,8 @@ public void testSyncedFlushVanishesOnReplay() throws IOException {
         EngineConfig config = engine.config();
         engine.close();
         engine = new InternalEngine(config);
-        engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+        TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), engine);
+        engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
         assertNull(
             "Sync ID must be gone since we have a document to replay",
             engine.getLastCommittedSegmentInfos().getUserData().get(Engine.SYNC_COMMIT_ID)
@@ -1489,7 +1766,7 @@ public void testForceMergeWithSoftDeletesRetention() throws Exception {
 
             long localCheckpoint = engine.getProcessedLocalCheckpoint();
             globalCheckpoint.set(randomLongBetween(0, localCheckpoint));
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
             final long safeCommitCheckpoint;
             try (GatedCloseable<IndexCommit> wrappedSafeCommit = engine.acquireSafeIndexCommit()) {
                 safeCommitCheckpoint = Long.parseLong(wrappedSafeCommit.get().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
@@ -1520,7 +1797,7 @@ public void testForceMergeWithSoftDeletesRetention() throws Exception {
                 indexSettings.getSoftDeleteRetentionOperations()
             );
             globalCheckpoint.set(localCheckpoint);
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
 
             engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID());
             assertConsistentHistoryBetweenTranslogAndLuceneIndex(engine);
@@ -1578,7 +1855,7 @@ public void testForceMergeWithSoftDeletesRetentionAndRecoverySource() throws Exc
             }
             engine.flush();
             globalCheckpoint.set(randomLongBetween(0, engine.getPersistedLocalCheckpoint()));
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
             final long minSeqNoToRetain;
             try (GatedCloseable<IndexCommit> wrappedSafeCommit = engine.acquireSafeIndexCommit()) {
                 long safeCommitLocalCheckpoint = Long.parseLong(
@@ -1626,12 +1903,12 @@ public void testForceMergeWithSoftDeletesRetentionAndRecoverySource() throws Exc
                 if (useRecoverySource == false) {
                     liveDocsWithSource.add(doc.id());
                 }
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
                 globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
                 engine.flush(randomBoolean(), true);
             } else {
                 globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
             }
             engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID());
             assertConsistentHistoryBetweenTranslogAndLuceneIndex(engine);
@@ -1989,7 +2266,7 @@ private int assertOpsOnPrimary(List<Engine.Operation> ops, long currentOpVersion
             final long conflictingTerm = conflictingSeqNo == lastOpSeqNo || randomBoolean() ? lastOpTerm + 1 : lastOpTerm;
             if (rarely()) {
                 currentTerm.set(currentTerm.get() + 1L);
-                engine.rollTranslogGeneration();
+                engine.translogManager().rollTranslogGeneration();
             }
             final long correctVersion = docDeleted ? Versions.MATCH_DELETED : lastOpVersion;
             logger.info(
@@ -2269,6 +2546,7 @@ class OpAndVersion {
         final Term uidTerm = newUid(doc);
         engine.index(indexForDoc(doc));
         final BiFunction<String, Engine.SearcherScope, Engine.Searcher> searcherFactory = engine::acquireSearcher;
+
         for (int i = 0; i < thread.length; i++) {
             thread[i] = new Thread(() -> {
                 startGun.countDown();
@@ -2277,10 +2555,12 @@ class OpAndVersion {
                 } catch (InterruptedException e) {
                     throw new AssertionError(e);
                 }
+
                 for (int op = 0; op < opsPerThread; op++) {
                     try (Engine.GetResult get = engine.get(new Engine.Get(true, false, doc.id(), uidTerm), searcherFactory)) {
+
                         FieldsVisitor visitor = new FieldsVisitor(true);
-                        get.docIdAndVersion().reader.document(get.docIdAndVersion().docId, visitor);
+                        get.docIdAndVersion().reader.storedFields().document(get.docIdAndVersion().docId, visitor);
                         List<String> values = new ArrayList<>(Strings.commaDelimitedListToSet(visitor.source().utf8ToString()));
                         String removed = op % 3 == 0 && values.size() > 0 ? values.remove(0) : null;
                         String added = "v_" + idGenerator.incrementAndGet();
@@ -2336,7 +2616,7 @@ class OpAndVersion {
 
         try (Engine.GetResult get = engine.get(new Engine.Get(true, false, doc.id(), uidTerm), searcherFactory)) {
             FieldsVisitor visitor = new FieldsVisitor(true);
-            get.docIdAndVersion().reader.document(get.docIdAndVersion().docId, visitor);
+            get.docIdAndVersion().reader.storedFields().document(get.docIdAndVersion().docId, visitor);
             List<String> values = Arrays.asList(Strings.commaDelimitedListToStringArray(visitor.source().utf8ToString()));
             assertThat(currentValues, equalTo(new HashSet<>(values)));
         }
@@ -2448,7 +2728,7 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
             );
 
             ReplicationTracker gcpTracker = (ReplicationTracker) initialEngine.config().getGlobalCheckpointSupplier();
-            gcpTracker.updateFromMaster(
+            gcpTracker.updateFromClusterManager(
                 1L,
                 new HashSet<>(Collections.singletonList(primary.allocationId().getId())),
                 new IndexShardRoutingTable.Builder(shardId).addShard(primary).build()
@@ -2463,7 +2743,7 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
                 );
                 countDownLatch.await();
             }
-            gcpTracker.updateFromMaster(
+            gcpTracker.updateFromClusterManager(
                 2L,
                 new HashSet<>(Collections.singletonList(primary.allocationId().getId())),
                 new IndexShardRoutingTable.Builder(shardId).addShard(primary).addShard(initializingReplica).build()
@@ -2471,7 +2751,7 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
             gcpTracker.initiateTracking(initializingReplica.allocationId().getId());
             gcpTracker.markAllocationIdAsInSync(initializingReplica.allocationId().getId(), replicaLocalCheckpoint);
             final ShardRouting replica = initializingReplica.moveToStarted();
-            gcpTracker.updateFromMaster(
+            gcpTracker.updateFromClusterManager(
                 3L,
                 new HashSet<>(Arrays.asList(primary.allocationId().getId(), replica.allocationId().getId())),
                 new IndexShardRoutingTable.Builder(shardId).addShard(primary).addShard(replica).build()
@@ -2535,7 +2815,7 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
                     }
                 }
 
-                initialEngine.syncTranslog(); // to advance persisted local checkpoint
+                initialEngine.translogManager().syncTranslog(); // to advance persisted local checkpoint
 
                 if (randomInt(10) < 3) {
                     // only update rarely as we do it every doc
@@ -2562,8 +2842,14 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
                 Long.parseLong(initialEngine.commitStats().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)),
                 equalTo(localCheckpoint)
             );
-            initialEngine.getTranslog().sync(); // to guarantee the global checkpoint is written to the translog checkpoint
-            assertThat(initialEngine.getTranslog().getLastSyncedGlobalCheckpoint(), equalTo(globalCheckpoint));
+            initialEngine.ensureOpen();
+            getTranslog(initialEngine).sync(); // to guarantee the global checkpoint is written to the translog
+                                               // checkpoint
+            initialEngine.ensureOpen();
+            assertThat(
+                assertAndGetInternalTranslogManager(initialEngine.translogManager()).getLastSyncedGlobalCheckpoint(),
+                equalTo(globalCheckpoint)
+            );
             assertThat(Long.parseLong(initialEngine.commitStats().getUserData().get(SequenceNumbers.MAX_SEQ_NO)), equalTo(maxSeqNo));
 
         } finally {
@@ -2571,14 +2857,20 @@ public void testSeqNoAndCheckpoints() throws IOException, InterruptedException {
         }
 
         try (InternalEngine recoveringEngine = new InternalEngine(initialEngine.config())) {
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            TranslogHandler translogHandler = createTranslogHandler(initialEngine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
 
             assertEquals(primarySeqNo, recoveringEngine.getSeqNoStats(-1).getMaxSeqNo());
             assertThat(
                 Long.parseLong(recoveringEngine.commitStats().getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)),
                 equalTo(primarySeqNo)
             );
-            assertThat(recoveringEngine.getTranslog().getLastSyncedGlobalCheckpoint(), equalTo(globalCheckpoint));
+            recoveringEngine.ensureOpen();
+            assertThat(
+                assertAndGetInternalTranslogManager(recoveringEngine.translogManager()).getLastSyncedGlobalCheckpoint(),
+                equalTo(globalCheckpoint)
+            );
             assertThat(
                 Long.parseLong(recoveringEngine.commitStats().getUserData().get(SequenceNumbers.MAX_SEQ_NO)),
                 // after recovering from translog, all docs have been flushed to Lucene segments, so here we will assert
@@ -2860,89 +3152,418 @@ public void testEnableGcDeletes() throws Exception {
             assertThat(indexResult.getResultType(), equalTo(Engine.Result.Type.FAILURE));
             assertThat(indexResult.getFailure(), instanceOf(VersionConflictEngineException.class));
 
-            // Get should still not find the document
-            getResult = engine.get(newGet(true, doc), searcherFactory);
-            assertThat(getResult.exists(), equalTo(false));
+            // Get should still not find the document
+            getResult = engine.get(newGet(true, doc), searcherFactory);
+            assertThat(getResult.exists(), equalTo(false));
+
+            // Try to index uid=2 with a too-old version, should fail:
+            Engine.Index index1 = new Engine.Index(
+                newUid(doc),
+                doc,
+                UNASSIGNED_SEQ_NO,
+                0,
+                2,
+                VersionType.EXTERNAL,
+                Engine.Operation.Origin.PRIMARY,
+                System.nanoTime(),
+                -1,
+                false,
+                UNASSIGNED_SEQ_NO,
+                0
+            );
+            indexResult = engine.index(index1);
+            assertThat(indexResult.getResultType(), equalTo(Engine.Result.Type.FAILURE));
+            assertThat(indexResult.getFailure(), instanceOf(VersionConflictEngineException.class));
+
+            // Get should not find the document
+            getResult = engine.get(newGet(true, doc), searcherFactory);
+            assertThat(getResult.exists(), equalTo(false));
+        }
+    }
+
+    public void testExtractShardId() {
+        try (Engine.Searcher test = this.engine.acquireSearcher("test", Engine.SearcherScope.INTERNAL)) {
+            ShardId shardId = ShardUtils.extractShardId(test.getDirectoryReader());
+            assertNotNull(shardId);
+            assertEquals(shardId, engine.config().getShardId());
+        }
+    }
+
+    /**
+     * Random test that throws random exception and ensures all references are
+     * counted down / released and resources are closed.
+     */
+    public void testFailStart() throws IOException {
+        // this test fails if any reader, searcher or directory is not closed - MDW FTW
+        final int iters = scaledRandomIntBetween(10, 100);
+        for (int i = 0; i < iters; i++) {
+            MockDirectoryWrapper wrapper = newMockDirectory();
+            wrapper.setFailOnOpenInput(randomBoolean());
+            wrapper.setAllowRandomFileNotFoundException(randomBoolean());
+            wrapper.setRandomIOExceptionRate(randomDouble());
+            wrapper.setRandomIOExceptionRateOnOpen(randomDouble());
+            final Path translogPath = createTempDir("testFailStart");
+            try (Store store = createStore(wrapper)) {
+                int refCount = store.refCount();
+                assertTrue("refCount: " + store.refCount(), store.refCount() > 0);
+                InternalEngine holder;
+                try {
+                    holder = createEngine(store, translogPath);
+                } catch (EngineCreationFailureException | IOException ex) {
+                    assertEquals(store.refCount(), refCount);
+                    continue;
+                }
+                assertEquals(store.refCount(), refCount + 1);
+                final int numStarts = scaledRandomIntBetween(1, 5);
+                for (int j = 0; j < numStarts; j++) {
+                    try {
+                        assertEquals(store.refCount(), refCount + 1);
+                        holder.close();
+                        holder = createEngine(store, translogPath);
+                        assertEquals(store.refCount(), refCount + 1);
+                    } catch (EngineCreationFailureException ex) {
+                        // all is fine
+                        assertEquals(store.refCount(), refCount);
+                        break;
+                    }
+                }
+                holder.close();
+                assertEquals(store.refCount(), refCount);
+            }
+        }
+    }
+
+    public void testUnreferencedFileCleanUpOnSegmentMergeFailureWithCleanUpEnabled() throws Exception {
+        MockDirectoryWrapper wrapper = newMockDirectory();
+        final CountDownLatch cleanupCompleted = new CountDownLatch(1);
+        MockDirectoryWrapper.Failure fail = new MockDirectoryWrapper.Failure() {
+            public boolean didFail1;
+            public boolean didFail2;
+
+            @Override
+            public void eval(MockDirectoryWrapper dir) throws IOException {
+                if (!doFail) {
+                    return;
+                }
+
+                // Fail segment merge with diskfull during merging terms.
+                if (callStackContainsAnyOf("mergeTerms") && !didFail1) {
+                    didFail1 = true;
+                    throw new IOException("No space left on device");
+                }
+                if (callStackContains(LiveDocsFormat.class, "writeLiveDocs") && !didFail2) {
+                    didFail2 = true;
+                    throw new IOException("No space left on device");
+                }
+            }
+        };
+
+        wrapper.failOn(fail);
+        try {
+            Store store = createStore(wrapper);
+            final Engine.EventListener eventListener = new Engine.EventListener() {
+                @Override
+                public void onFailedEngine(String reason, Exception e) {
+                    try {
+                        // extra0 file is added as a part of
+                        // https://lucene.apache.org/core/7_2_1/test-framework/org/apache/lucene/mockfile/ExtrasFS.html
+                        // Safe to remove from file count along with write.lock without impacting the test.
+                        long fileCount = Arrays.stream(store.directory().listAll())
+                            .filter(file -> file.equals("write.lock") == false && ExtrasFS.isExtra(file) == false)
+                            .count();
+
+                        // Since only one document is committed and unreferenced files are cleaned up,
+                        // there are 4 files (*cfs, *cfe, *si and segments_*).
+                        assertThat(fileCount, equalTo(4L));
+                        wrapper.close();
+                        store.close();
+                        engine.close();
+                        cleanupCompleted.countDown();
+                    } catch (IOException ex) {
+                        throw new AssertionError(ex);
+                    }
+                }
+            };
+
+            final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+            final long primaryTerm = randomLongBetween(1, Long.MAX_VALUE);
+            final AtomicLong retentionLeasesVersion = new AtomicLong();
+            final AtomicReference<RetentionLeases> retentionLeasesHolder = new AtomicReference<>(
+                new RetentionLeases(primaryTerm, retentionLeasesVersion.get(), Collections.emptyList())
+            );
+            InternalEngine engine = createEngine(
+                config(
+                    defaultSettings,
+                    store,
+                    createTempDir(),
+                    newMergePolicy(),
+                    null,
+                    null,
+                    null,
+                    globalCheckpoint::get,
+                    retentionLeasesHolder::get,
+                    new NoneCircuitBreakerService(),
+                    eventListener
+                )
+            );
+
+            List<Segment> segments = engine.segments(true);
+            assertThat(segments.isEmpty(), equalTo(true));
+
+            ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), B_1, null);
+            engine.index(indexForDoc(doc));
+            engine.refresh("test");
+            engine.flush();
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(1));
+
+            ParsedDocument doc2 = testParsedDocument("2", null, testDocumentWithTextField(), B_2, null);
+            engine.index(indexForDoc(doc2));
+            engine.refresh("test");
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(2));
+
+            fail.setDoFail();
+            // IndexWriter can throw either IOException or IllegalStateException depending on whether tragedy is set or not.
+            expectThrowsAnyOf(
+                Arrays.asList(IOException.class, IllegalStateException.class),
+                () -> engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID())
+            );
+
+            assertTrue(cleanupCompleted.await(10, TimeUnit.SECONDS));
+            // Cleanup count will be incremented whenever cleanup is performed correctly.
+            long unreferencedFileCleanUpsPerformed = engine.unreferencedFileCleanUpsPerformed();
+            assertThat(unreferencedFileCleanUpsPerformed, equalTo(1L));
+        } catch (Exception ex) {
+            throw new AssertionError(ex);
+        }
+    }
+
+    public void testUnreferencedFileCleanUpOnSegmentMergeFailureWithCleanUpDisabled() throws Exception {
+        MockDirectoryWrapper wrapper = newMockDirectory();
+        final CountDownLatch cleanupCompleted = new CountDownLatch(1);
+        MockDirectoryWrapper.Failure fail = new MockDirectoryWrapper.Failure() {
+            public boolean didFail1;
+            public boolean didFail2;
+
+            @Override
+            public void eval(MockDirectoryWrapper dir) throws IOException {
+                if (!doFail) {
+                    return;
+                }
+                if (callStackContainsAnyOf("mergeTerms") && !didFail1) {
+                    didFail1 = true;
+                    throw new IOException("No space left on device");
+                }
+                if (callStackContains(LiveDocsFormat.class, "writeLiveDocs") && !didFail2) {
+                    didFail2 = true;
+                    throw new IOException("No space left on device");
+                }
+            }
+        };
+
+        wrapper.failOn(fail);
+        try {
+            Store store = createStore(wrapper);
+            final Engine.EventListener eventListener = new Engine.EventListener() {
+                @Override
+                public void onFailedEngine(String reason, Exception e) {
+                    try {
+                        // extra0 file is added as a part of
+                        // https://lucene.apache.org/core/7_2_1/test-framework/org/apache/lucene/mockfile/ExtrasFS.html
+                        // Safe to remove from file count along with write.lock without impacting the test
+                        long fileCount = Arrays.stream(store.directory().listAll())
+                            .filter(file -> file.equals("write.lock") == false && ExtrasFS.isExtra(file) == false)
+                            .count();
+
+                        // Since now cleanup is not happening now, all unrefrenced files now be present as well.
+                        assertThat(fileCount, equalTo(13L));
+                        wrapper.close();
+                        store.close();
+                        engine.close();
+                        cleanupCompleted.countDown();
+                    } catch (IOException ex) {
+                        throw new AssertionError(ex);
+                    }
+                }
+            };
+
+            final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+            final long primaryTerm = randomLongBetween(1, Long.MAX_VALUE);
+            final AtomicLong retentionLeasesVersion = new AtomicLong();
+            final AtomicReference<RetentionLeases> retentionLeasesHolder = new AtomicReference<>(
+                new RetentionLeases(primaryTerm, retentionLeasesVersion.get(), Collections.emptyList())
+            );
+            InternalEngine engine = createEngine(
+                config(
+                    defaultSettings,
+                    store,
+                    createTempDir(),
+                    newMergePolicy(),
+                    null,
+                    null,
+                    null,
+                    globalCheckpoint::get,
+                    retentionLeasesHolder::get,
+                    new NoneCircuitBreakerService(),
+                    eventListener
+                )
+            );
+
+            // Disable cleanup
+            final IndexSettings indexSettings = engine.config().getIndexSettings();
+            final IndexMetadata indexMetadata = IndexMetadata.builder(indexSettings.getIndexMetadata())
+                .settings(
+                    Settings.builder().put(indexSettings.getSettings()).put(IndexSettings.INDEX_UNREFERENCED_FILE_CLEANUP.getKey(), false)
+                )
+                .build();
+            indexSettings.updateIndexMetadata(indexMetadata);
+
+            List<Segment> segments = engine.segments(true);
+            assertThat(segments.isEmpty(), equalTo(true));
+
+            ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), B_1, null);
+            engine.index(indexForDoc(doc));
+            engine.refresh("test");
+            engine.flush();
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(1));
+
+            ParsedDocument doc2 = testParsedDocument("2", null, testDocumentWithTextField(), B_2, null);
+            engine.index(indexForDoc(doc2));
+            engine.refresh("test");
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(2));
+
+            fail.setDoFail();
+            // IndexWriter can throw either IOException or IllegalStateException depending on whether tragedy is set or not.
+            expectThrowsAnyOf(
+                Arrays.asList(IOException.class, IllegalStateException.class),
+                () -> engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID())
+            );
+
+            assertTrue(cleanupCompleted.await(10, TimeUnit.SECONDS));
+            // Cleanup count will not be incremented whenever cleanup is disabled.
+            long unreferencedFileCleanUpsPerformed = engine.unreferencedFileCleanUpsPerformed();
+            assertThat(unreferencedFileCleanUpsPerformed, equalTo(0L));
+        } catch (Exception ex) {
+            throw new AssertionError(ex);
+        }
+    }
+
+    public void testUnreferencedFileCleanUpFailsOnSegmentMergeFailureWhenDirectoryClosed() throws Exception {
+        MockDirectoryWrapper wrapper = newMockDirectory();
+        final CountDownLatch cleanupCompleted = new CountDownLatch(1);
+        MockDirectoryWrapper.Failure fail = new MockDirectoryWrapper.Failure() {
+            public boolean didFail1;
+            public boolean didFail2;
+
+            @Override
+            public void eval(MockDirectoryWrapper dir) throws IOException {
+                if (!doFail) {
+                    return;
+                }
+                if (callStackContainsAnyOf("mergeTerms") && !didFail1) {
+                    didFail1 = true;
+                    throw new IOException("No space left on device");
+                }
+                if (callStackContains(LiveDocsFormat.class, "writeLiveDocs") && !didFail2) {
+                    didFail2 = true;
+                    throw new IOException("No space left on device");
+                }
+            }
+        };
+
+        wrapper.failOn(fail);
+        MockLogAppender mockAppender = MockLogAppender.createForLoggers(Loggers.getLogger(Engine.class, shardId));
+        try {
+            Store store = createStore(wrapper);
+            final Engine.EventListener eventListener = new Engine.EventListener() {
+                @Override
+                public void onFailedEngine(String reason, Exception e) {
+                    try {
+                        store.close();
+                        engine.close();
+                        mockAppender.assertAllExpectationsMatched();
+                        mockAppender.close();
+                        cleanupCompleted.countDown();
+                    } catch (IOException ex) {
+                        throw new RuntimeException(ex);
+                    }
+                }
+            };
+
+            final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+            final long primaryTerm = randomLongBetween(1, Long.MAX_VALUE);
+            final AtomicLong retentionLeasesVersion = new AtomicLong();
+            final AtomicReference<RetentionLeases> retentionLeasesHolder = new AtomicReference<>(
+                new RetentionLeases(primaryTerm, retentionLeasesVersion.get(), Collections.emptyList())
+            );
+            InternalEngine engine = createEngine(
+                config(
+                    defaultSettings,
+                    store,
+                    createTempDir(),
+                    newMergePolicy(),
+                    null,
+                    null,
+                    null,
+                    globalCheckpoint::get,
+                    retentionLeasesHolder::get,
+                    new NoneCircuitBreakerService(),
+                    eventListener
+                )
+            );
+
+            List<Segment> segments = engine.segments(true);
+            assertThat(segments.isEmpty(), equalTo(true));
+
+            ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), B_1, null);
+            engine.index(indexForDoc(doc));
+            engine.refresh("test");
+            engine.flush();
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(1));
+
+            ParsedDocument doc2 = testParsedDocument("2", null, testDocumentWithTextField(), B_2, null);
+            engine.index(indexForDoc(doc2));
+            engine.refresh("test");
+
+            segments = engine.segments(false);
+            assertThat(segments.size(), equalTo(2));
+
+            fail.setDoFail();
+            // Close the store so that unreferenced file cleanup will fail.
+            store.close();
 
-            // Try to index uid=2 with a too-old version, should fail:
-            Engine.Index index1 = new Engine.Index(
-                newUid(doc),
-                doc,
-                UNASSIGNED_SEQ_NO,
-                0,
-                2,
-                VersionType.EXTERNAL,
-                Engine.Operation.Origin.PRIMARY,
-                System.nanoTime(),
-                -1,
-                false,
-                UNASSIGNED_SEQ_NO,
-                0
+            final String message = "Error while deleting unreferenced file *";
+            mockAppender.start();
+            mockAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation("expected message", Engine.class.getCanonicalName(), Level.ERROR, message)
             );
-            indexResult = engine.index(index1);
-            assertThat(indexResult.getResultType(), equalTo(Engine.Result.Type.FAILURE));
-            assertThat(indexResult.getFailure(), instanceOf(VersionConflictEngineException.class));
-
-            // Get should not find the document
-            getResult = engine.get(newGet(true, doc), searcherFactory);
-            assertThat(getResult.exists(), equalTo(false));
-        }
-    }
 
-    public void testExtractShardId() {
-        try (Engine.Searcher test = this.engine.acquireSearcher("test", Engine.SearcherScope.INTERNAL)) {
-            ShardId shardId = ShardUtils.extractShardId(test.getDirectoryReader());
-            assertNotNull(shardId);
-            assertEquals(shardId, engine.config().getShardId());
-        }
-    }
+            // IndexWriter can throw either IOException or IllegalStateException depending on whether tragedy is set or not.
+            expectThrowsAnyOf(
+                Arrays.asList(IOException.class, IllegalStateException.class),
+                () -> engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID())
+            );
 
-    /**
-     * Random test that throws random exception and ensures all references are
-     * counted down / released and resources are closed.
-     */
-    public void testFailStart() throws IOException {
-        // this test fails if any reader, searcher or directory is not closed - MDW FTW
-        final int iters = scaledRandomIntBetween(10, 100);
-        for (int i = 0; i < iters; i++) {
-            MockDirectoryWrapper wrapper = newMockDirectory();
-            wrapper.setFailOnOpenInput(randomBoolean());
-            wrapper.setAllowRandomFileNotFoundException(randomBoolean());
-            wrapper.setRandomIOExceptionRate(randomDouble());
-            wrapper.setRandomIOExceptionRateOnOpen(randomDouble());
-            final Path translogPath = createTempDir("testFailStart");
-            try (Store store = createStore(wrapper)) {
-                int refCount = store.refCount();
-                assertTrue("refCount: " + store.refCount(), store.refCount() > 0);
-                InternalEngine holder;
-                try {
-                    holder = createEngine(store, translogPath);
-                } catch (EngineCreationFailureException | IOException ex) {
-                    assertEquals(store.refCount(), refCount);
-                    continue;
-                }
-                assertEquals(store.refCount(), refCount + 1);
-                final int numStarts = scaledRandomIntBetween(1, 5);
-                for (int j = 0; j < numStarts; j++) {
-                    try {
-                        assertEquals(store.refCount(), refCount + 1);
-                        holder.close();
-                        holder = createEngine(store, translogPath);
-                        assertEquals(store.refCount(), refCount + 1);
-                    } catch (EngineCreationFailureException ex) {
-                        // all is fine
-                        assertEquals(store.refCount(), refCount);
-                        break;
-                    }
-                }
-                holder.close();
-                assertEquals(store.refCount(), refCount);
-            }
+            assertTrue(cleanupCompleted.await(10, TimeUnit.SECONDS));
+            // Cleanup count will not be incremented whenever there is some issue with cleanup.
+            long unreferencedFileCleanUpsPerformed = engine.unreferencedFileCleanUpsPerformed();
+            assertThat(unreferencedFileCleanUpsPerformed, equalTo(0L));
+        } catch (Exception ex) {
+            throw new AssertionError(ex);
         }
     }
 
     public void testSettings() {
-        CodecService codecService = new CodecService(null, logger);
+        CodecService codecService = new CodecService(null, engine.config().getIndexSettings(), logger);
         LiveIndexWriterConfig currentIndexWriterConfig = engine.getCurrentIndexWriterConfig();
 
         assertEquals(engine.config().getCodec().getName(), codecService.codec(codecName).getName());
@@ -2982,24 +3603,41 @@ public void testCurrentTranslogUUIIDIsCommitted() throws IOException {
 
                 try (InternalEngine engine = createEngine(config)) {
                     engine.index(firstIndexRequest);
-                    engine.syncTranslog(); // to advance persisted local checkpoint
+                    engine.translogManager().syncTranslog(); // to advance persisted local checkpoint
                     assertEquals(engine.getProcessedLocalCheckpoint(), engine.getPersistedLocalCheckpoint());
                     globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
-                    expectThrows(IllegalStateException.class, () -> engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE));
+                    expectThrows(
+                        IllegalStateException.class,
+                        () -> engine.translogManager()
+                            .recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE)
+                    );
                     Map<String, String> userData = engine.getLastCommittedSegmentInfos().getUserData();
-                    assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
+                    engine.ensureOpen();
+                    assertEquals(
+                        assertAndGetInternalTranslogManager(engine.translogManager()).getTranslogUUID(),
+                        userData.get(Translog.TRANSLOG_UUID_KEY)
+                    );
                 }
             }
             // open and recover tlog
             {
                 for (int i = 0; i < 2; i++) {
                     try (InternalEngine engine = new InternalEngine(config)) {
-                        expectThrows(IllegalStateException.class, engine::ensureCanFlush);
+                        expectThrows(IllegalStateException.class, engine.translogManager()::ensureCanFlush);
                         Map<String, String> userData = engine.getLastCommittedSegmentInfos().getUserData();
-                        assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
-                        engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                        engine.ensureOpen();
+                        assertEquals(
+                            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslogUUID(),
+                            userData.get(Translog.TRANSLOG_UUID_KEY)
+                        );
+                        TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), engine);
+                        engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                         userData = engine.getLastCommittedSegmentInfos().getUserData();
-                        assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
+                        engine.ensureOpen();
+                        assertEquals(
+                            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getTranslogUUID(),
+                            userData.get(Translog.TRANSLOG_UUID_KEY)
+                        );
                     }
                 }
             }
@@ -3014,10 +3652,15 @@ public void testCurrentTranslogUUIIDIsCommitted() throws IOException {
                 store.associateIndexWithNewTranslog(translogUUID);
                 try (InternalEngine engine = new InternalEngine(config)) {
                     Map<String, String> userData = engine.getLastCommittedSegmentInfos().getUserData();
-                    assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
-                    engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
-                    assertEquals(2, engine.getTranslog().currentFileGeneration());
-                    assertEquals(0L, engine.getTranslog().stats().getUncommittedOperations());
+                    engine.ensureOpen();
+                    assertEquals(
+                        assertAndGetInternalTranslogManager(engine.translogManager()).getTranslogUUID(),
+                        userData.get(Translog.TRANSLOG_UUID_KEY)
+                    );
+                    engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
+                    engine.ensureOpen();
+                    assertEquals(2, assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration());
+                    assertEquals(0L, engine.translogManager().getTranslogStats().getUncommittedOperations());
                 }
             }
 
@@ -3026,10 +3669,18 @@ public void testCurrentTranslogUUIIDIsCommitted() throws IOException {
                 for (int i = 0; i < 2; i++) {
                     try (InternalEngine engine = new InternalEngine(config)) {
                         Map<String, String> userData = engine.getLastCommittedSegmentInfos().getUserData();
-                        assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
-                        engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                        engine.ensureOpen();
+                        assertEquals(
+                            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslogUUID(),
+                            userData.get(Translog.TRANSLOG_UUID_KEY)
+                        );
+                        engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                         userData = engine.getLastCommittedSegmentInfos().getUserData();
-                        assertEquals(engine.getTranslog().getTranslogUUID(), userData.get(Translog.TRANSLOG_UUID_KEY));
+                        engine.ensureOpen();
+                        assertEquals(
+                            assertAndGetInternalTranslogManager(engine.translogManager()).getTranslogUUID(),
+                            userData.get(Translog.TRANSLOG_UUID_KEY)
+                        );
                     }
                 }
             }
@@ -3097,7 +3748,7 @@ public void testTranslogReplayWithFailure() throws IOException {
                 try {
                     engine = createEngine(store, translogPath);
                     started = true;
-                } catch (EngineException | IOException e) {
+                } catch (EngineException | TranslogException | IOException e) {
                     logger.trace("exception on open", e);
                 }
                 directory.setRandomIOExceptionRateOnOpen(0.0);
@@ -3150,10 +3801,10 @@ protected void commitIndexWriter(IndexWriter writer, Translog translog) throws I
                     }
                 }
             ) {
-                engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 final ParsedDocument doc1 = testParsedDocument("1", null, testDocumentWithTextField(), SOURCE, null);
                 engine.index(indexForDoc(doc1));
-                engine.syncTranslog(); // to advance local checkpoint
+                engine.translogManager().syncTranslog(); // to advance local checkpoint
                 assertEquals(engine.getProcessedLocalCheckpoint(), engine.getPersistedLocalCheckpoint());
                 globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
                 throwErrorOnCommit.set(true);
@@ -3165,12 +3816,14 @@ protected void commitIndexWriter(IndexWriter writer, Translog translog) throws I
                     config(indexSettings, store, translogPath, newMergePolicy(), null, null, globalCheckpointSupplier)
                 )
             ) {
-                engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 assertVisibleCount(engine, 1);
                 final long localCheckpoint = Long.parseLong(
                     engine.getLastCommittedSegmentInfos().userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY)
                 );
-                final long committedGen = engine.getTranslog().getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
+                engine.ensureOpen();
+                final long committedGen = assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog()
+                    .getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
                 for (int gen = 1; gen < committedGen; gen++) {
                     final Path genFile = translogPath.resolve(Translog.getFilename(gen));
                     assertFalse(genFile + " wasn't cleaned up", Files.exists(genFile));
@@ -3204,7 +3857,7 @@ public void testSkipTranslogReplay() throws IOException {
         assertVisibleCount(engine, numDocs);
         engine.close();
         try (InternalEngine engine = new InternalEngine(config)) {
-            engine.skipTranslogRecovery();
+            engine.translogManager().skipTranslogRecovery();
             try (Engine.Searcher searcher = engine.acquireSearcher("test", Engine.SearcherScope.INTERNAL)) {
                 TopDocs topDocs = searcher.search(new MatchAllDocsQuery(), randomIntBetween(numDocs, numDocs + 10));
                 assertThat(topDocs.totalHits.value, equalTo(0L));
@@ -3246,19 +3899,20 @@ public void testTranslogReplay() throws IOException {
             assertThat(indexResult.getVersion(), equalTo(1L));
         }
         assertVisibleCount(engine, numDocs);
-        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings());
+        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings(), engine);
 
         engine.close();
         // we need to reuse the engine config unless the parser.mappingModified won't work
         engine = new InternalEngine(copy(engine.config(), inSyncGlobalCheckpointSupplier));
-        engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings(), engine);
+        engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
         engine.refresh("warm_up");
 
         assertVisibleCount(engine, numDocs, false);
         assertEquals(numDocs, translogHandler.appliedOperations());
 
         engine.close();
-        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings());
+        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings(), engine);
         engine = createEngine(store, primaryTranslogDir, inSyncGlobalCheckpointSupplier);
         engine.refresh("warm_up");
         assertVisibleCount(engine, numDocs, false);
@@ -3312,7 +3966,7 @@ public void testTranslogReplay() throws IOException {
         }
 
         engine.close();
-        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings());
+        translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings(), engine);
         engine = createEngine(store, primaryTranslogDir, inSyncGlobalCheckpointSupplier);
         engine.refresh("warm_up");
         try (Engine.Searcher searcher = engine.acquireSearcher("test")) {
@@ -3354,13 +4008,15 @@ public void testRecoverFromForeignTranslog() throws IOException {
             assertThat(index.getVersion(), equalTo(1L));
         }
         assertVisibleCount(engine, numDocs);
-        Translog.TranslogGeneration generation = engine.getTranslog().getGeneration();
+        engine.ensureOpen();
+        Translog.TranslogGeneration generation = assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog()
+            .getGeneration();
         engine.close();
 
         final Path badTranslogLog = createTempDir();
         final String badUUID = Translog.createEmptyTranslog(badTranslogLog, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
-        Translog translog = new Translog(
-            new TranslogConfig(shardId, badTranslogLog, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE),
+        Translog translog = new LocalTranslog(
+            new TranslogConfig(shardId, badTranslogLog, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
             badUUID,
             createTranslogDeletionPolicy(INDEX_SETTINGS),
             () -> SequenceNumbers.NO_OPS_PERFORMED,
@@ -3377,33 +4033,33 @@ public void testRecoverFromForeignTranslog() throws IOException {
             shardId,
             translog.location(),
             config.getIndexSettings(),
-            BigArrays.NON_RECYCLING_INSTANCE
+            BigArrays.NON_RECYCLING_INSTANCE,
+            ""
         );
 
-        EngineConfig brokenConfig = new EngineConfig(
-            shardId,
-            threadPool,
-            config.getIndexSettings(),
-            null,
-            store,
-            newMergePolicy(),
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            IndexSearcher.getDefaultQueryCache(),
-            IndexSearcher.getDefaultQueryCachingPolicy(),
-            translogConfig,
-            TimeValue.timeValueMinutes(5),
-            config.getExternalRefreshListener(),
-            config.getInternalRefreshListener(),
-            null,
-            new NoneCircuitBreakerService(),
-            () -> UNASSIGNED_SEQ_NO,
-            () -> RetentionLeases.EMPTY,
-            primaryTerm::get,
-            tombstoneDocSupplier()
-        );
+        EngineConfig brokenConfig = new EngineConfig.Builder().shardId(shardId)
+            .threadPool(threadPool)
+            .indexSettings(config.getIndexSettings())
+            .warmer(null)
+            .store(store)
+            .mergePolicy(newMergePolicy())
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(IndexSearcher.getDefaultQueryCache())
+            .queryCachingPolicy(IndexSearcher.getDefaultQueryCachingPolicy())
+            .translogConfig(translogConfig)
+            .flushMergesAfter(TimeValue.timeValueMinutes(5))
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(config.getInternalRefreshListener())
+            .indexSort(null)
+            .circuitBreakerService(new NoneCircuitBreakerService())
+            .globalCheckpointSupplier(() -> UNASSIGNED_SEQ_NO)
+            .retentionLeasesSupplier(() -> RetentionLeases.EMPTY)
+            .primaryTermSupplier(primaryTerm::get)
+            .tombstoneDocSupplier(tombstoneDocSupplier())
+            .build();
         expectThrows(EngineCreationFailureException.class, () -> new InternalEngine(brokenConfig));
 
         engine = createEngine(store, primaryTranslogDir); // and recover again!
@@ -3423,34 +4079,36 @@ public CustomTranslogDeletionPolicy(IndexSettings indexSettings, Supplier<Retent
         TranslogDeletionPolicyFactory translogDeletionPolicyFactory = CustomTranslogDeletionPolicy::new;
 
         EngineConfig config = engine.config();
-        EngineConfig configWithCustomTranslogDeletionPolicyFactory = new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            config.getIndexSettings(),
-            config.getWarmer(),
-            config.getStore(),
-            config.getMergePolicy(),
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            config.getTranslogConfig(),
-            translogDeletionPolicyFactory,
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            config.getInternalRefreshListener(),
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            config.getGlobalCheckpointSupplier(),
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            config.getTombstoneDocSupplier()
-        );
+        EngineConfig configWithCustomTranslogDeletionPolicyFactory = new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(config.getIndexSettings())
+            .warmer(config.getWarmer())
+            .store(config.getStore())
+            .mergePolicy(config.getMergePolicy())
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(config.getTranslogConfig())
+            .translogDeletionPolicyFactory(translogDeletionPolicyFactory)
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(config.getInternalRefreshListener())
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+            .build();
         engine.close();
         engine = createEngine(configWithCustomTranslogDeletionPolicyFactory);
-        assertTrue(engine.getTranslog().getDeletionPolicy() instanceof CustomTranslogDeletionPolicy);
+        engine.ensureOpen();
+        assertTrue(
+            assertAndGetInternalTranslogManager(engine.translogManager()).getDeletionPolicy() instanceof CustomTranslogDeletionPolicy
+        );
     }
 
     public void testShardNotAvailableExceptionWhenEngineClosedConcurrently() throws IOException, InterruptedException {
@@ -3628,13 +4286,13 @@ public void testHandleDocumentFailure() throws Exception {
                 assertNotNull(indexResult.getTranslogLocation());
                 engine.index(indexForDoc(doc2));
 
-                // test non document level failure is thrown
-                if (randomBoolean()) {
-                    // simulate close by corruption
-                    throwingIndexWriter.get().setThrowFailure(null);
-                    UncheckedIOException uncheckedIOException = expectThrows(UncheckedIOException.class, () -> {
+                try (engine) {
+                    // test non document level failure is thrown
+                    if (randomBoolean()) {
+                        // simulate close by corruption
+                        throwingIndexWriter.get().setThrowFailure(null);
                         Engine.Index index = indexForDoc(doc3);
-                        index.parsedDoc().rootDoc().add(new StoredField("foo", "bar") {
+                        index.parsedDoc().rootDoc().add(new KeywordField("foo", "bar", org.apache.lucene.document.Field.Store.YES) {
                             // this is a hack to add a failure during store document which triggers a tragic event
                             // and in turn fails the engine
                             @Override
@@ -3642,13 +4300,14 @@ public BytesRef binaryValue() {
                                 throw new UncheckedIOException(new MockDirectoryWrapper.FakeIOException());
                             }
                         });
-                        engine.index(index);
-                    });
-                    assertTrue(uncheckedIOException.getCause() instanceof MockDirectoryWrapper.FakeIOException);
-                } else {
-                    // normal close
-                    engine.close();
+
+                        final IndexResult r = engine.index(index);
+                        assertThat(r.isCreated(), equalTo(false));
+                        assertThat(r.getFailure(), instanceOf(UncheckedIOException.class));
+                        assertThat(r.getFailure().getCause(), instanceOf(MockDirectoryWrapper.FakeIOException.class));
+                    }
                 }
+
                 // now the engine is closed check we respond correctly
                 expectThrows(AlreadyClosedException.class, () -> engine.index(indexForDoc(doc1)));
                 expectThrows(AlreadyClosedException.class, () -> engine.delete(new Engine.Delete("", newUid(doc1), primaryTerm.get())));
@@ -3679,7 +4338,7 @@ public ParsedDocument newDeleteTombstoneDoc(String id) {
                         // this is a hack to add a failure during store document which triggers a tragic event
                         // and in turn fails the engine
                         @Override
-                        public BytesRef binaryValue() {
+                        public IndexableFieldType fieldType() {
                             throw tragicException;
                         }
                     });
@@ -4282,7 +4941,8 @@ public void testEngineMaxTimestampIsInitialized() throws IOException {
         }
         try (Store store = createStore(newFSDirectory(storeDir)); InternalEngine engine = new InternalEngine(configSupplier.apply(store))) {
             assertEquals(IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP, engine.segmentsStats(false, false).getMaxUnsafeAutoIdTimestamp());
-            engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            TranslogHandler translogHandler = createTranslogHandler(configSupplier.apply(store).getIndexSettings(), engine);
+            engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             assertEquals(timestamp1, engine.segmentsStats(false, false).getMaxUnsafeAutoIdTimestamp());
             final ParsedDocument doc = testParsedDocument(
                 "1",
@@ -4719,7 +5379,9 @@ public void testSequenceNumberAdvancesToMaxSeqOnEngineOpenOnPrimary() throws Bro
             IOUtils.close(initialEngine);
         }
         try (InternalEngine recoveringEngine = new InternalEngine(initialEngine.config())) {
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            TranslogHandler translogHandler = createTranslogHandler(initialEngine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             recoveringEngine.fillSeqNoGaps(2);
             assertEquals(recoveringEngine.getProcessedLocalCheckpoint(), recoveringEngine.getPersistedLocalCheckpoint());
             assertThat(recoveringEngine.getProcessedLocalCheckpoint(), greaterThanOrEqualTo((long) (docs - 1)));
@@ -4893,27 +5555,35 @@ public void testNoOps() throws IOException {
                     engine.config().getMergePolicy()
                 )
             );
-            noOpEngine = new InternalEngine(noopEngineConfig, IndexWriter.MAX_DOCS, supplier) {
+            noOpEngine = new InternalEngine(
+                noopEngineConfig,
+                IndexWriter.MAX_DOCS,
+                supplier,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER
+            ) {
                 @Override
                 protected long doGenerateSeqNoForOperation(Operation operation) {
                     throw new UnsupportedOperationException();
                 }
             };
-            noOpEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            noOpEngine.translogManager().recoverFromTranslog(translogHandler, noOpEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             final int gapsFilled = noOpEngine.fillSeqNoGaps(primaryTerm.get());
             final String reason = "filling gaps";
             noOpEngine.noOp(new Engine.NoOp(maxSeqNo + 1, primaryTerm.get(), LOCAL_TRANSLOG_RECOVERY, System.nanoTime(), reason));
             assertThat(noOpEngine.getProcessedLocalCheckpoint(), equalTo((long) (maxSeqNo + 1)));
-            assertThat(noOpEngine.getTranslog().stats().getUncommittedOperations(), equalTo(gapsFilled));
+            noOpEngine.ensureOpen();
+            assertThat(noOpEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(gapsFilled));
             noOpEngine.noOp(
                 new Engine.NoOp(maxSeqNo + 2, primaryTerm.get(), randomFrom(PRIMARY, REPLICA, PEER_RECOVERY), System.nanoTime(), reason)
             );
             assertThat(noOpEngine.getProcessedLocalCheckpoint(), equalTo((long) (maxSeqNo + 2)));
-            assertThat(noOpEngine.getTranslog().stats().getUncommittedOperations(), equalTo(gapsFilled + 1));
+            assertThat(noOpEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(gapsFilled + 1));
             // skip to the op that we added to the translog
             Translog.Operation op;
             Translog.Operation last = null;
-            try (Translog.Snapshot snapshot = noOpEngine.getTranslog().newSnapshot()) {
+            try (
+                Translog.Snapshot snapshot = assertAndGetInternalTranslogManager(noOpEngine.translogManager()).getTranslog().newSnapshot()
+            ) {
                 while ((op = snapshot.next()) != null) {
                     last = op;
                 }
@@ -5027,8 +5697,10 @@ public void testMinGenerationForSeqNo() throws IOException, BrokenBarrierExcepti
                 getStallingSeqNoGenerator(latchReference, barrier, stall, expectedLocalCheckpoint)
             );
             final InternalEngine finalActualEngine = actualEngine;
-            final Translog translog = finalActualEngine.getTranslog();
-            final long generation = finalActualEngine.getTranslog().currentFileGeneration();
+            finalActualEngine.ensureOpen();
+            final Translog translog = assertAndGetInternalTranslogManager(finalActualEngine.translogManager()).getTranslog();
+            final long generation = assertAndGetInternalTranslogManager(finalActualEngine.translogManager()).getTranslog()
+                .currentFileGeneration();
             for (int i = 0; i < numberOfTriplets; i++) {
                 /*
                  * Index three documents with the first and last landing in the same generation and the middle document being stalled until
@@ -5133,28 +5805,32 @@ public void testRestoreLocalHistoryFromTranslog() throws IOException {
                     final ParsedDocument doc = testParsedDocument(id, null, testDocumentWithTextField(), SOURCE, null);
                     engine.index(replicaIndexForDoc(doc, 1, seqNo, false));
                     if (rarely()) {
-                        engine.rollTranslogGeneration();
+                        engine.translogManager().rollTranslogGeneration();
                     }
                     if (rarely()) {
                         engine.flush();
                     }
                 }
                 globalCheckpoint.set(randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, engine.getPersistedLocalCheckpoint()));
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
                 prevSeqNoStats = engine.getSeqNoStats(globalCheckpoint.get());
                 prevDocs = getDocIds(engine, true);
             }
             try (InternalEngine engine = new InternalEngine(engineConfig)) {
-                final long currentTranslogGeneration = engine.getTranslog().currentFileGeneration();
-                engine.recoverFromTranslog(translogHandler, globalCheckpoint.get());
-                engine.restoreLocalHistoryFromTranslog(translogHandler);
+                engine.ensureOpen();
+                final long currentTranslogGeneration = engine.translogManager().getTranslog().currentFileGeneration();
+                TranslogHandler translogHandler = createTranslogHandler(engineConfig.getIndexSettings(), engine);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), globalCheckpoint.get());
+                engine.translogManager().restoreLocalHistoryFromTranslog(engine.getProcessedLocalCheckpoint(), translogHandler);
                 assertThat(getDocIds(engine, true), equalTo(prevDocs));
                 SeqNoStats seqNoStats = engine.getSeqNoStats(globalCheckpoint.get());
                 assertThat(seqNoStats.getLocalCheckpoint(), equalTo(prevSeqNoStats.getLocalCheckpoint()));
                 assertThat(seqNoStats.getMaxSeqNo(), equalTo(prevSeqNoStats.getMaxSeqNo()));
+                engine.ensureOpen();
                 assertThat(
                     "restore from local translog must not add operations to translog",
-                    engine.getTranslog().totalOperationsByMinGen(currentTranslogGeneration),
+                    assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog()
+                        .totalOperationsByMinGen(currentTranslogGeneration),
                     equalTo(0)
                 );
             }
@@ -5179,8 +5855,8 @@ public void testFillUpSequenceIdGapsOnRecovery() throws IOException {
                     replicaEngine.index(replicaIndexForDoc(doc, 1, indexResult.getSeqNo(), false));
                 }
             }
-            engine.syncTranslog(); // to advance local checkpoint
-            replicaEngine.syncTranslog(); // to advance local checkpoint
+            engine.translogManager().syncTranslog(); // to advance local checkpoint
+            replicaEngine.translogManager().syncTranslog(); // to advance local checkpoint
             checkpointOnReplica = replicaEngine.getProcessedLocalCheckpoint();
         } finally {
             IOUtils.close(replicaEngine);
@@ -5195,8 +5871,10 @@ public void testFillUpSequenceIdGapsOnRecovery() throws IOException {
             assertEquals(maxSeqIDOnReplica, replicaEngine.getSeqNoStats(-1).getMaxSeqNo());
             assertEquals(checkpointOnReplica, replicaEngine.getProcessedLocalCheckpoint());
             recoveringEngine = new InternalEngine(copy(replicaEngine.config(), globalCheckpoint::get));
-            assertEquals(numDocsOnReplica, getTranslog(recoveringEngine).stats().getUncommittedOperations());
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            assertEquals(numDocsOnReplica, recoveringEngine.translogManager().getTranslogStats().getUncommittedOperations());
+            TranslogHandler translogHandler = createTranslogHandler(replicaEngine.config().getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             assertEquals(maxSeqIDOnReplica, recoveringEngine.getSeqNoStats(-1).getMaxSeqNo());
             assertEquals(checkpointOnReplica, recoveringEngine.getProcessedLocalCheckpoint());
             assertEquals((maxSeqIDOnReplica + 1) - numDocsOnReplica, recoveringEngine.fillSeqNoGaps(2));
@@ -5227,11 +5905,14 @@ public void testFillUpSequenceIdGapsOnRecovery() throws IOException {
 
         // now do it again to make sure we preserve values etc.
         try {
-            recoveringEngine = new InternalEngine(copy(replicaEngine.config(), globalCheckpoint::get));
+            EngineConfig config = copy(replicaEngine.config(), globalCheckpoint::get);
+            recoveringEngine = new InternalEngine(config);
             if (flushed) {
-                assertThat(recoveringEngine.getTranslogStats().getUncommittedOperations(), equalTo(0));
+                assertThat(recoveringEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(0));
             }
-            recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), recoveringEngine);
+            recoveringEngine.translogManager()
+                .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             assertEquals(maxSeqIDOnReplica, recoveringEngine.getSeqNoStats(-1).getMaxSeqNo());
             assertEquals(maxSeqIDOnReplica, recoveringEngine.getProcessedLocalCheckpoint());
             assertEquals(0, recoveringEngine.fillSeqNoGaps(3));
@@ -5376,7 +6057,7 @@ public void testSeqNoGenerator() throws IOException {
                 "routing",
                 Collections.singletonList(document),
                 source,
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 null
             );
 
@@ -5461,7 +6142,7 @@ protected void commitIndexWriter(IndexWriter writer, Translog translog) throws I
                 super.commitIndexWriter(writer, translog);
             }
         }) {
-            engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+            engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
             int numDocs = scaledRandomIntBetween(10, 100);
             for (int docId = 0; docId < numDocs; docId++) {
                 ParseContext.Document document = testDocumentWithTextField();
@@ -5469,7 +6150,7 @@ protected void commitIndexWriter(IndexWriter writer, Translog translog) throws I
                 engine.index(indexForDoc(testParsedDocument(Integer.toString(docId), null, document, B_1, null)));
                 if (frequently()) {
                     globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
-                    engine.syncTranslog();
+                    engine.translogManager().syncTranslog();
                 }
                 if (frequently()) {
                     engine.flush(randomBoolean(), true);
@@ -5636,7 +6317,7 @@ public void testCleanUpCommitsWhenGlobalCheckpointAdvanced() throws Exception {
             }
             engine.flush(false, randomBoolean());
             globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
             List<IndexCommit> commits = DirectoryReader.listCommits(store.directory());
             assertThat(
                 Long.parseLong(commits.get(0).getUserData().get(SequenceNumbers.MAX_SEQ_NO)),
@@ -5650,9 +6331,10 @@ public void testCleanUpCommitsWhenGlobalCheckpointAdvanced() throws Exception {
             }
             // Global checkpoint advanced enough - only the last commit is kept.
             globalCheckpoint.set(randomLongBetween(engine.getPersistedLocalCheckpoint(), Long.MAX_VALUE));
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
             assertThat(DirectoryReader.listCommits(store.directory()), contains(commits.get(commits.size() - 1)));
-            assertThat(engine.getTranslog().totalOperations(), equalTo(0));
+            engine.ensureOpen();
+            assertThat(engine.translogManager().getTranslogStats().estimatedNumberOfOperations(), equalTo(0));
         }
     }
 
@@ -5675,7 +6357,7 @@ public void testCleanupCommitsWhenReleaseSnapshot() throws Exception {
                 snapshots.add(engine.acquireSafeIndexCommit()); // taking snapshots from the safe commit.
             }
             globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
-            engine.syncTranslog();
+            engine.translogManager().syncTranslog();
             final List<IndexCommit> commits = DirectoryReader.listCommits(store.directory());
             for (int i = 0; i < numSnapshots - 1; i++) {
                 snapshots.get(i).close();
@@ -5690,12 +6372,13 @@ public void testCleanupCommitsWhenReleaseSnapshot() throws Exception {
     public void testShouldPeriodicallyFlush() throws Exception {
         assertThat("Empty engine does not need flushing", engine.shouldPeriodicallyFlush(), equalTo(false));
         // A new engine may have more than one empty translog files - the test should account this extra.
-        final Translog translog = engine.getTranslog();
+        engine.ensureOpen();
+        final Translog translog = assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog();
         final IntSupplier uncommittedTranslogOperationsSinceLastCommit = () -> {
             long localCheckpoint = Long.parseLong(engine.getLastCommittedSegmentInfos().userData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
             return translog.totalOperationsByMinGen(translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration);
         };
-        final long extraTranslogSizeInNewEngine = engine.getTranslog().stats().getUncommittedSizeInBytes()
+        final long extraTranslogSizeInNewEngine = engine.translogManager().getTranslogStats().getUncommittedSizeInBytes()
             - Translog.DEFAULT_HEADER_SIZE_IN_BYTES;
         int numDocs = between(10, 100);
         for (int id = 0; id < numDocs; id++) {
@@ -5703,10 +6386,11 @@ public void testShouldPeriodicallyFlush() throws Exception {
             engine.index(indexForDoc(doc));
         }
         assertThat("Not exceeded translog flush threshold yet", engine.shouldPeriodicallyFlush(), equalTo(false));
+        engine.ensureOpen();
         long flushThreshold = RandomNumbers.randomLongBetween(
             random(),
             120,
-            engine.getTranslog().stats().getUncommittedSizeInBytes() - extraTranslogSizeInNewEngine
+            engine.translogManager().getTranslogStats().getUncommittedSizeInBytes() - extraTranslogSizeInNewEngine
         );
         final IndexSettings indexSettings = engine.config().getIndexSettings();
         final IndexMetadata indexMetadata = IndexMetadata.builder(indexSettings.getIndexMetadata())
@@ -5722,7 +6406,8 @@ public void testShouldPeriodicallyFlush() throws Exception {
             indexSettings.getTranslogRetentionSize(),
             indexSettings.getSoftDeleteRetentionOperations()
         );
-        assertThat(engine.getTranslog().stats().getUncommittedOperations(), equalTo(numDocs));
+        engine.ensureOpen();
+        assertThat(engine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(numDocs));
         assertThat(engine.shouldPeriodicallyFlush(), equalTo(true));
         engine.flush();
         assertThat(uncommittedTranslogOperationsSinceLastCommit.getAsInt(), equalTo(0));
@@ -5778,11 +6463,13 @@ public void testShouldPeriodicallyFlushAfterMerge() throws Exception {
             indexSettings.getTranslogRetentionSize(),
             indexSettings.getSoftDeleteRetentionOperations()
         );
-        assertThat(engine.getTranslog().stats().getUncommittedOperations(), equalTo(1));
+        engine.ensureOpen();
+        assertThat(engine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(1));
         assertThat(engine.shouldPeriodicallyFlush(), equalTo(false));
         doc = testParsedDocument(Integer.toString(1), null, testDocumentWithTextField(), SOURCE, null);
         engine.index(indexForDoc(doc));
-        assertThat(engine.getTranslog().stats().getUncommittedOperations(), equalTo(2));
+        engine.ensureOpen();
+        assertThat(engine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(2));
         engine.refresh("test");
         engine.forceMerge(false, 1, false, false, false, UUIDs.randomBase64UUID());
         assertBusy(() -> {
@@ -5817,8 +6504,9 @@ public void testStressShouldPeriodicallyFlush() throws Exception {
             final long seqno = randomLongBetween(Math.max(0, localCheckPoint), localCheckPoint + 5);
             final ParsedDocument doc = testParsedDocument(Long.toString(seqno), null, testDocumentWithTextField(), SOURCE, null);
             engine.index(replicaIndexForDoc(doc, 1L, seqno, false));
-            if (rarely() && engine.getTranslog().shouldRollGeneration()) {
-                engine.rollTranslogGeneration();
+            engine.ensureOpen();
+            if (rarely() && engine.translogManager().shouldRollTranslogGeneration()) {
+                engine.translogManager().rollTranslogGeneration();
             }
             if (rarely() || engine.shouldPeriodicallyFlush()) {
                 engine.flush();
@@ -6039,8 +6727,9 @@ public void testTrimUnsafeCommits() throws Exception {
                     }
                 }
                 globalCheckpoint.set(randomInt(maxSeqNo));
-                engine.syncTranslog();
-                minTranslogGen = engine.getTranslog().getMinFileGeneration();
+                engine.translogManager().syncTranslog();
+                engine.ensureOpen();
+                minTranslogGen = assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration();
             }
 
             store.trimUnsafeCommits(config.getTranslogConfig().getTranslogPath());
@@ -6112,8 +6801,28 @@ public void testHistoryBasedOnSource() throws Exception {
                 }
             }
             List<Translog.Operation> luceneOps = readAllOperationsBasedOnSource(engine);
+            // todo remove in next release
+            List<Translog.Operation> translogOps = readAllOperationsBasedOnTranslog(engine);
             assertThat(luceneOps.stream().map(o -> o.seqNo()).collect(Collectors.toList()), containsInAnyOrder(expectedSeqNos.toArray()));
+            assertThat(translogOps.stream().map(o -> o.seqNo()).collect(Collectors.toList()), containsInAnyOrder(expectedSeqNos.toArray()));
+        }
+    }
+
+    /**
+     * Test creating new snapshot from translog file
+     *
+     * @deprecated reading history operations from the translog file is deprecated and will be removed in the next release
+     */
+    @Deprecated
+    private static List<Translog.Operation> readAllOperationsBasedOnTranslog(Engine engine) throws IOException {
+        final List<Translog.Operation> operations = new ArrayList<>();
+        try (Translog.Snapshot snapshot = engine.newChangesSnapshotFromTranslogFile("test", 0, Long.MAX_VALUE, false)) {
+            Translog.Operation op;
+            while ((op = snapshot.next()) != null) {
+                operations.add(op);
+            }
         }
+        return operations;
     }
 
     public void testLuceneHistoryOnPrimary() throws Exception {
@@ -6221,7 +6930,7 @@ public void testKeepMinRetainedSeqNoByMergePolicy() throws IOException {
             }
             existingSeqNos.add(result.getSeqNo());
             if (randomBoolean()) {
-                engine.syncTranslog(); // advance persisted local checkpoint
+                engine.translogManager().syncTranslog(); // advance persisted local checkpoint
                 assertEquals(engine.getProcessedLocalCheckpoint(), engine.getPersistedLocalCheckpoint());
                 globalCheckpoint.set(
                     randomLongBetween(globalCheckpoint.get(), engine.getLocalCheckpointTracker().getPersistedCheckpoint())
@@ -6296,6 +7005,7 @@ public void testLastRefreshCheckpoint() throws Exception {
                 while (done.get() == false) {
                     long checkPointBeforeRefresh = engine.getProcessedLocalCheckpoint();
                     engine.refresh("test", randomFrom(Engine.SearcherScope.values()), true);
+                    assertThat(engine.currentOngoingRefreshCheckpoint(), greaterThanOrEqualTo(engine.lastRefreshedCheckpoint()));
                     assertThat(engine.lastRefreshedCheckpoint(), greaterThanOrEqualTo(checkPointBeforeRefresh));
                 }
             });
@@ -6309,6 +7019,7 @@ public void testLastRefreshCheckpoint() throws Exception {
             thread.join();
         }
         engine.refresh("test");
+        assertThat(engine.currentOngoingRefreshCheckpoint(), greaterThanOrEqualTo(engine.lastRefreshedCheckpoint()));
         assertThat(engine.lastRefreshedCheckpoint(), equalTo(engine.getProcessedLocalCheckpoint()));
     }
 
@@ -6457,7 +7168,7 @@ public void testRebuildLocalCheckpointTrackerAndVersionMap() throws Exception {
                     flushedOperations.add(op);
                     applyOperation(engine, op);
                     if (randomBoolean()) {
-                        engine.syncTranslog();
+                        engine.translogManager().syncTranslog();
                         globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
                     }
                     if (randomInt(100) < 10) {
@@ -6517,7 +7228,8 @@ public void testRebuildLocalCheckpointTrackerAndVersionMap() throws Exception {
                         equalTo(seqNosInSafeCommit.contains(op.seqNo()))
                     );
                 }
-                engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), engine);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 assertThat(getDocIds(engine, true), equalTo(docs));
             }
         }
@@ -6571,8 +7283,10 @@ public void testStoreHonorsLuceneVersion() throws IOException {
     public void testMaxSeqNoInCommitUserData() throws Exception {
         AtomicBoolean running = new AtomicBoolean(true);
         Thread rollTranslog = new Thread(() -> {
-            while (running.get() && engine.getTranslog().currentFileGeneration() < 500) {
-                engine.rollTranslogGeneration(); // make adding operations to translog slower
+            engine.ensureOpen();
+            while (running.get()
+                && assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration() < 500) {
+                engine.translogManager().rollTranslogGeneration(); // make adding operations to translog slower
             }
         });
         rollTranslog.start();
@@ -6711,7 +7425,7 @@ public void testRecoverFromLocalTranslog() throws Exception {
                 for (Engine.Operation op : operations) {
                     applyOperation(engine, op);
                     if (randomBoolean()) {
-                        engine.syncTranslog();
+                        engine.translogManager().syncTranslog();
                         globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
                     }
                     if (randomInt(100) < 10) {
@@ -6726,21 +7440,23 @@ public void testRecoverFromLocalTranslog() throws Exception {
                 }
                 if (randomBoolean()) {
                     // engine is flushed properly before shutting down.
-                    engine.syncTranslog();
+                    engine.translogManager().syncTranslog();
                     globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
                     engine.flush();
                 }
                 docs = getDocIds(engine, true);
             }
             try (InternalEngine engine = new InternalEngine(config)) {
+                translogHandler = createTranslogHandler(engine.engineConfig.getIndexSettings(), engine);
                 engine.onSettingsChanged(TimeValue.MINUS_ONE, ByteSizeValue.ZERO, 0);
-                engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 assertThat(getDocIds(engine, randomBoolean()), equalTo(docs));
                 if (engine.getSeqNoStats(globalCheckpoint.get()).getMaxSeqNo() == globalCheckpoint.get()) {
+                    engine.ensureOpen();
                     assertThat(
                         "engine should trim all unreferenced translog after recovery",
-                        engine.getTranslog().getMinFileGeneration(),
-                        equalTo(engine.getTranslog().currentFileGeneration())
+                        assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().getMinFileGeneration(),
+                        equalTo(assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration())
                     );
                 }
             }
@@ -6812,8 +7528,8 @@ public void testAlwaysRecordReplicaOrPeerRecoveryOperationsToTranslog() throws E
             );
         }
         primaryTerm.set(randomLongBetween(primaryTerm.get(), Long.MAX_VALUE));
-        engine.rollTranslogGeneration();
-        engine.trimOperationsFromTranslog(primaryTerm.get(), NO_OPS_PERFORMED); // trim everything in translog
+        engine.translogManager().rollTranslogGeneration();
+        engine.translogManager().trimOperationsFromTranslog(primaryTerm.get(), NO_OPS_PERFORMED); // trim everything in translog
         try (Translog.Snapshot snapshot = getTranslog(engine).newSnapshot()) {
             assertThat(snapshot.totalOperations(), equalTo(0));
             assertNull(snapshot.next());
@@ -7026,32 +7742,32 @@ public void testNotWarmUpSearcherInEngineCtor() throws Exception {
                 config.getTranslogConfig().getShardId(),
                 createTempDir(),
                 config.getTranslogConfig().getIndexSettings(),
-                config.getTranslogConfig().getBigArrays()
-            );
-            EngineConfig configWithWarmer = new EngineConfig(
-                config.getShardId(),
-                config.getThreadPool(),
-                config.getIndexSettings(),
-                warmer,
-                store,
-                config.getMergePolicy(),
-                config.getAnalyzer(),
-                config.getSimilarity(),
-                new CodecService(null, logger),
-                config.getEventListener(),
-                config.getQueryCache(),
-                config.getQueryCachingPolicy(),
-                translogConfig,
-                config.getFlushMergesAfter(),
-                config.getExternalRefreshListener(),
-                config.getInternalRefreshListener(),
-                config.getIndexSort(),
-                config.getCircuitBreakerService(),
-                config.getGlobalCheckpointSupplier(),
-                config.retentionLeasesSupplier(),
-                config.getPrimaryTermSupplier(),
-                config.getTombstoneDocSupplier()
+                config.getTranslogConfig().getBigArrays(),
+                ""
             );
+            EngineConfig configWithWarmer = new EngineConfig.Builder().shardId(config.getShardId())
+                .threadPool(config.getThreadPool())
+                .indexSettings(config.getIndexSettings())
+                .warmer(warmer)
+                .store(store)
+                .mergePolicy(config.getMergePolicy())
+                .analyzer(config.getAnalyzer())
+                .similarity(config.getSimilarity())
+                .codecService(new CodecService(null, config.getIndexSettings(), logger))
+                .eventListener(config.getEventListener())
+                .queryCache(config.getQueryCache())
+                .queryCachingPolicy(config.getQueryCachingPolicy())
+                .translogConfig(translogConfig)
+                .flushMergesAfter(config.getFlushMergesAfter())
+                .externalRefreshListener(config.getExternalRefreshListener())
+                .internalRefreshListener(config.getInternalRefreshListener())
+                .indexSort(config.getIndexSort())
+                .circuitBreakerService(config.getCircuitBreakerService())
+                .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+                .retentionLeasesSupplier(config.retentionLeasesSupplier())
+                .primaryTermSupplier(config.getPrimaryTermSupplier())
+                .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+                .build();
             try (InternalEngine engine = createEngine(configWithWarmer)) {
                 assertThat(warmedUpReaders, empty());
                 assertThat(
@@ -7178,4 +7894,258 @@ public void testMaxDocsOnReplica() throws Exception {
             restoreIndexWriterMaxDocs();
         }
     }
+
+    public void testGetSegmentInfosSnapshot_AllSnapshotFilesPreservedAcrossCommit() throws Exception {
+        IOUtils.close(store, engine);
+        store = createStore();
+        engine = createEngine(store, createTempDir());
+        List<Engine.Operation> operations = generateHistoryOnReplica(
+            randomIntBetween(1, 100),
+            randomBoolean(),
+            randomBoolean(),
+            randomBoolean()
+        );
+        for (Engine.Operation op : operations) {
+            applyOperation(engine, op);
+        }
+        engine.refresh("test");
+        try (GatedCloseable<SegmentInfos> snapshot = engine.getSegmentInfosSnapshot()) {
+            Collection<String> files = snapshot.get().files(true);
+            Set<String> localFiles = Set.of(store.directory().listAll());
+            for (String file : files) {
+                assertTrue("Local directory contains file " + file, localFiles.contains(file));
+            }
+
+            engine.flush(true, true);
+
+            try (
+                final GatedCloseable<SegmentInfos> snapshotAfterFlush = engine.getSegmentInfosSnapshot();
+                final GatedCloseable<IndexCommit> commit = engine.acquireLastIndexCommit(false)
+            ) {
+                final SegmentInfos segmentInfos = snapshotAfterFlush.get();
+                assertNotEquals(segmentInfos.getSegmentsFileName(), snapshot.get().getSegmentsFileName());
+                assertEquals(commit.get().getSegmentsFileName(), segmentInfos.getSegmentsFileName());
+            }
+
+            // original files are preserved.
+            localFiles = Set.of(store.directory().listAll());
+            for (String file : files) {
+                assertTrue("Local directory contains file " + file, localFiles.contains(file));
+            }
+        }
+    }
+
+    public void testGetSegmentInfosSnapshot_LatestCommitOnDiskHasHigherGenThanReader() throws Exception {
+        IOUtils.close(store, engine);
+        store = createStore();
+        engine = createEngine(store, createTempDir());
+        // to simulate this we need concurrent flush/refresh.
+        AtomicBoolean run = new AtomicBoolean(true);
+        AtomicInteger docId = new AtomicInteger(0);
+        Thread refresher = new Thread(() -> {
+            while (run.get()) {
+                try {
+                    engine.index(indexForDoc(createParsedDoc(Integer.toString(docId.getAndIncrement()), null)));
+                    engine.refresh("test");
+                    getSnapshotAndAssertFilesExistLocally();
+                } catch (Exception e) {
+                    Assert.fail();
+                }
+            }
+        });
+        refresher.start();
+        try {
+            for (int i = 0; i < 10; i++) {
+                engine.flush(true, true);
+                getSnapshotAndAssertFilesExistLocally();
+            }
+        } catch (Exception e) {
+            Assert.fail();
+        } finally {
+            run.set(false);
+            refresher.join();
+        }
+    }
+
+    private void getSnapshotAndAssertFilesExistLocally() throws IOException {
+        try (GatedCloseable<SegmentInfos> snapshot = engine.getSegmentInfosSnapshot()) {
+            Collection<String> files = snapshot.get().files(true);
+            Set<String> localFiles = Set.of(store.directory().listAll());
+            for (String file : files) {
+                assertTrue("Local directory contains file " + file, localFiles.contains(file));
+            }
+        }
+    }
+
+    public void testGetProcessedLocalCheckpoint() throws IOException {
+        final long expectedLocalCheckpoint = 1L;
+        IOUtils.close(store, engine);
+        // set up mock
+        final LocalCheckpointTracker mockCheckpointTracker = mock(LocalCheckpointTracker.class);
+        when(mockCheckpointTracker.getProcessedCheckpoint()).thenReturn(expectedLocalCheckpoint);
+
+        Store store = createStore();
+        InternalEngine engine = createEngine(store, createTempDir(), (a, b) -> mockCheckpointTracker);
+
+        long actualLocalCheckpoint = engine.getProcessedLocalCheckpoint();
+        assertEquals(expectedLocalCheckpoint, actualLocalCheckpoint);
+        verify(mockCheckpointTracker, atLeastOnce()).getProcessedCheckpoint();
+        store.close();
+        engine.close();
+    }
+
+    public void testGetMaxSeqNoRefreshedWithoutRefresh() throws IOException {
+        IOUtils.close(store, engine);
+
+        final Settings.Builder settings = Settings.builder().put(defaultSettings.getSettings()).put("index.refresh_interval", "300s");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        Store store = createStore();
+        InternalEngine engine = createEngine(indexSettings, store, createTempDir(), newMergePolicy());
+
+        int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            engine.index(indexForDoc(createParsedDoc(Integer.toString(i), null)));
+        }
+
+        try (Engine.Searcher searcher = engine.acquireSearcher("test", Engine.SearcherScope.INTERNAL)) {
+            assertEquals(NO_OPS_PERFORMED, engine.getMaxSeqNoFromSearcher(searcher));
+        }
+
+        store.close();
+        engine.close();
+    }
+
+    public void testGetMaxSeqNoRefreshed() throws IOException {
+        IOUtils.close(store, engine);
+
+        final Settings.Builder settings = Settings.builder().put(defaultSettings.getSettings()).put("index.refresh_interval", "300s");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        Store store = createStore();
+        InternalEngine engine = createEngine(indexSettings, store, createTempDir(), newMergePolicy());
+
+        int totalNumberOfDocsRefreshed = 0;
+        for (int j = 0; j < randomIntBetween(1, 10); j++) {
+            int numDocs = randomIntBetween(10, 100);
+            for (int i = totalNumberOfDocsRefreshed; i < (totalNumberOfDocsRefreshed + numDocs); i++) {
+                engine.index(indexForDoc(createParsedDoc(Integer.toString(i), null)));
+            }
+            // this is just to make sure that refresh post flush has the same impact.
+            if (randomBoolean()) {
+                engine.refresh("test");
+            } else {
+                engine.flush();
+            }
+            totalNumberOfDocsRefreshed += numDocs;
+        }
+        // Optionally, index more docs without refreshing. These should not be part of getMaxSeqNoRefreshed
+        if (randomBoolean()) {
+            for (int i = totalNumberOfDocsRefreshed; i < (totalNumberOfDocsRefreshed + randomIntBetween(10, 100)); i++) {
+                engine.index(indexForDoc(createParsedDoc(Integer.toString(i), null)));
+            }
+        }
+
+        try (Engine.Searcher searcher = engine.acquireSearcher("test", Engine.SearcherScope.INTERNAL)) {
+            assertEquals(totalNumberOfDocsRefreshed - 1, engine.getMaxSeqNoFromSearcher(searcher));
+        }
+
+        store.close();
+        engine.close();
+    }
+
+    public void testGetMaxSeqNoFromSegmentInfos() throws IOException {
+        IOUtils.close(store, engine);
+
+        final Settings.Builder settings = Settings.builder().put(defaultSettings.getSettings()).put("index.refresh_interval", "300s");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        Store store = createStore();
+        InternalEngine engine = createEngine(indexSettings, store, createTempDir(), newMergePolicy());
+
+        int totalNumberOfDocsRefreshed = 0;
+        for (int j = 0; j < randomIntBetween(1, 10); j++) {
+            int numDocs = randomIntBetween(10, 100);
+            for (int i = totalNumberOfDocsRefreshed; i < (totalNumberOfDocsRefreshed + numDocs); i++) {
+                engine.index(indexForDoc(createParsedDoc(Integer.toString(i), null)));
+            }
+            // this is just to make sure that refresh post flush has the same impact.
+            if (randomBoolean()) {
+                engine.refresh("test");
+            } else {
+                engine.flush();
+            }
+            totalNumberOfDocsRefreshed += numDocs;
+        }
+        // Optionally, index more docs without refreshing. These should not be part of getMaxSeqNoRefreshed
+        if (randomBoolean()) {
+            for (int i = totalNumberOfDocsRefreshed; i < (totalNumberOfDocsRefreshed + randomIntBetween(10, 100)); i++) {
+                engine.index(indexForDoc(createParsedDoc(Integer.toString(i), null)));
+            }
+        }
+
+        try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = engine.getSegmentInfosSnapshot()) {
+            assertEquals(totalNumberOfDocsRefreshed - 1, engine.getMaxSeqNoFromSegmentInfos(segmentInfosGatedCloseable.get()));
+        }
+
+        store.close();
+        engine.close();
+    }
+
+    public void testGetMaxSeqNoFromSegmentInfosConcurrentWrites() throws IOException, BrokenBarrierException, InterruptedException {
+        IOUtils.close(store, engine);
+
+        final Settings.Builder settings = Settings.builder().put(defaultSettings.getSettings()).put("index.refresh_interval", "300s");
+        final IndexMetadata indexMetadata = IndexMetadata.builder(defaultSettings.getIndexMetadata()).settings(settings).build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(indexMetadata);
+
+        Store store = createStore();
+        InternalEngine engine = createEngine(indexSettings, store, createTempDir(), newMergePolicy());
+
+        final int numIndexingThreads = scaledRandomIntBetween(3, 8);
+        final int numDocsPerThread = randomIntBetween(500, 1000);
+        final CyclicBarrier barrier = new CyclicBarrier(numIndexingThreads + 1);
+        final List<Thread> indexingThreads = new ArrayList<>();
+        final CountDownLatch doneLatch = new CountDownLatch(numIndexingThreads);
+        // create N indexing threads to index documents simultaneously
+        for (int threadNum = 0; threadNum < numIndexingThreads; threadNum++) {
+            final int threadIdx = threadNum;
+            Thread indexingThread = new Thread(() -> {
+                try {
+                    barrier.await(); // wait for all threads to start at the same time
+                    // index random number of docs
+                    for (int i = 0; i < numDocsPerThread; i++) {
+                        final String id = "thread" + threadIdx + "#" + i;
+                        ParsedDocument doc = testParsedDocument(id, null, testDocument(), B_1, null);
+                        engine.index(indexForDoc(doc));
+                    }
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                } finally {
+                    doneLatch.countDown();
+                }
+
+            });
+            indexingThreads.add(indexingThread);
+        }
+
+        // start the indexing threads
+        for (Thread thread : indexingThreads) {
+            thread.start();
+        }
+        barrier.await(); // wait for indexing threads to all be ready to start
+        assertTrue(doneLatch.await(10, TimeUnit.SECONDS));
+
+        engine.refresh("test");
+
+        try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = engine.getSegmentInfosSnapshot()) {
+            assertEquals(numIndexingThreads * numDocsPerThread - 1, engine.getMaxSeqNoFromSegmentInfos(segmentInfosGatedCloseable.get()));
+        }
+
+        store.close();
+        engine.close();
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/engine/LiveVersionMapTests.java b/server/src/test/java/org/opensearch/index/engine/LiveVersionMapTests.java
index b1e033232420b..8ac584b3fa923 100644
--- a/server/src/test/java/org/opensearch/index/engine/LiveVersionMapTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/LiveVersionMapTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.index.engine;
 
+import org.apache.lucene.tests.util.RamUsageTester;
+import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.tests.util.RamUsageTester;
-import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/index/engine/LuceneChangesSnapshotTests.java b/server/src/test/java/org/opensearch/index/engine/LuceneChangesSnapshotTests.java
index e3117e179e7fa..b9b0e64d8811f 100644
--- a/server/src/test/java/org/opensearch/index/engine/LuceneChangesSnapshotTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/LuceneChangesSnapshotTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.engine;
 
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ParsedDocument;
@@ -226,7 +226,7 @@ public void testSkipNonRootOfNestedDocuments() throws Exception {
                 engine.refresh("test");
             }
             if (rarely()) {
-                engine.rollTranslogGeneration();
+                engine.translogManager().rollTranslogGeneration();
             }
             if (rarely()) {
                 engine.flush();
@@ -300,11 +300,12 @@ class Follower extends Thread {
             this.leader = leader;
             this.isDone = isDone;
             this.readLatch = readLatch;
+            this.engine = createEngine(createStore(), createTempDir());
             this.translogHandler = new TranslogHandler(
                 xContentRegistry(),
-                IndexSettingsModule.newIndexSettings(shardId.getIndexName(), leader.engineConfig.getIndexSettings().getSettings())
+                IndexSettingsModule.newIndexSettings(shardId.getIndexName(), leader.engineConfig.getIndexSettings().getSettings()),
+                engine
             );
-            this.engine = createEngine(createStore(), createTempDir());
         }
 
         void pullOperations(InternalEngine follower) throws IOException {
@@ -315,7 +316,7 @@ void pullOperations(InternalEngine follower) throws IOException {
                 long batchSize = randomLongBetween(0, 100);
                 long toSeqNo = Math.min(fromSeqNo + batchSize, leaderCheckpoint);
                 try (Translog.Snapshot snapshot = leader.newChangesSnapshot("test", fromSeqNo, toSeqNo, true, randomBoolean())) {
-                    translogHandler.run(follower, snapshot);
+                    translogHandler.run(snapshot);
                 }
             }
         }
diff --git a/server/src/test/java/org/opensearch/index/engine/NRTReplicationEngineTests.java b/server/src/test/java/org/opensearch/index/engine/NRTReplicationEngineTests.java
new file mode 100644
index 0000000000000..805271b05988c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/engine/NRTReplicationEngineTests.java
@@ -0,0 +1,587 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.search.ReferenceManager;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.util.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lucene.Lucene;
+import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.TestTranslog;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.IndexSettingsModule;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.seqno.SequenceNumbers.LOCAL_CHECKPOINT_KEY;
+import static org.opensearch.index.seqno.SequenceNumbers.MAX_SEQ_NO;
+import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
+import static org.hamcrest.Matchers.equalTo;
+
+public class NRTReplicationEngineTests extends EngineTestCase {
+
+    private static final IndexSettings INDEX_SETTINGS = IndexSettingsModule.newIndexSettings(
+        "index",
+        Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build()
+    );
+
+    public void testCreateEngine() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            final SegmentInfos latestSegmentInfos = nrtEngine.getLatestSegmentInfos();
+            final SegmentInfos lastCommittedSegmentInfos = nrtEngine.getLastCommittedSegmentInfos();
+            assertEquals(latestSegmentInfos.version, lastCommittedSegmentInfos.version);
+            assertEquals(latestSegmentInfos.getGeneration(), lastCommittedSegmentInfos.getGeneration());
+            assertEquals(latestSegmentInfos.getUserData(), lastCommittedSegmentInfos.getUserData());
+            assertEquals(latestSegmentInfos.files(true), lastCommittedSegmentInfos.files(true));
+
+            assertTrue(nrtEngine.segments(true).isEmpty());
+
+            try (final GatedCloseable<IndexCommit> indexCommitGatedCloseable = nrtEngine.acquireLastIndexCommit(false)) {
+                final IndexCommit indexCommit = indexCommitGatedCloseable.get();
+                assertEquals(indexCommit.getUserData(), lastCommittedSegmentInfos.getUserData());
+                assertTrue(indexCommit.getFileNames().containsAll(lastCommittedSegmentInfos.files(true)));
+            }
+        }
+    }
+
+    public void testCreateEngineWithException() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+        try {
+            // Passing null translogPath to induce failure
+            final EngineConfig replicaConfig = config(
+                defaultSettings,
+                nrtEngineStore,
+                null,
+                NoMergePolicy.INSTANCE,
+                null,
+                null,
+                globalCheckpoint::get
+            );
+            new NRTReplicationEngine(replicaConfig);
+        } catch (Exception e) {
+            // Ignore as engine creation will fail
+        }
+        assertEquals(1, nrtEngineStore.refCount());
+        nrtEngineStore.close();
+    }
+
+    public void testEngineWritesOpsToTranslog() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            List<Engine.Operation> operations = generateHistoryOnReplica(
+                between(1, 500),
+                randomBoolean(),
+                randomBoolean(),
+                randomBoolean()
+            );
+            for (Engine.Operation op : operations) {
+                applyOperation(engine, op);
+                applyOperation(nrtEngine, op);
+            }
+
+            assertEquals(nrtEngine.getTranslogLastWriteLocation(), engine.getTranslogLastWriteLocation());
+            assertEquals(nrtEngine.getLastSyncedGlobalCheckpoint(), engine.getLastSyncedGlobalCheckpoint());
+
+            // we don't index into nrtEngine, so get the doc ids from the regular engine.
+            final List<DocIdSeqNoAndSource> docs = getDocIds(engine, true);
+
+            // close the NRTEngine, it will commit on close and we'll reuse its store for an IE.
+            nrtEngine.close();
+
+            // recover a new engine from the nrtEngine's xlog.
+            nrtEngine.syncTranslog();
+            try (InternalEngine engine = new InternalEngine(nrtEngine.config())) {
+                TranslogHandler translogHandler = createTranslogHandler(nrtEngine.config().getIndexSettings(), engine);
+                engine.translogManager().recoverFromTranslog(translogHandler, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
+                assertEquals(getDocIds(engine, true), docs);
+            }
+            assertEngineCleanedUp(nrtEngine, assertAndGetInternalTranslogManager(nrtEngine.translogManager()).getDeletionPolicy());
+        }
+    }
+
+    public void testUpdateSegments_replicaReceivesSISWithHigherGen() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            // assume we start at the same gen.
+            assertEquals(2, nrtEngine.getLatestSegmentInfos().getGeneration());
+            assertEquals(nrtEngine.getLatestSegmentInfos().getGeneration(), nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(engine.getLatestSegmentInfos().getGeneration(), nrtEngine.getLatestSegmentInfos().getGeneration());
+
+            // flush the primary engine - we don't need any segments, just force a new commit point.
+            engine.flush(true, true);
+            assertEquals(3, engine.getLatestSegmentInfos().getGeneration());
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+            assertEquals(3, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(3, nrtEngine.getLatestSegmentInfos().getGeneration());
+        }
+    }
+
+    public void testUpdateSegments_replicaReceivesSISWithLowerGen() throws IOException {
+        // if the replica is already at segments_N that is received, it will commit segments_N+1.
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            assertEquals(5, nrtEngine.getLatestSegmentInfos().getVersion());
+            nrtEngine.getLatestSegmentInfos().changed();
+            nrtEngine.getLatestSegmentInfos().changed();
+            assertEquals(7, nrtEngine.getLatestSegmentInfos().getVersion());
+            assertEquals(2, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+
+            // commit the infos to push us to segments_3.
+            nrtEngine.flush();
+            assertEquals(3, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(3, nrtEngine.getLatestSegmentInfos().getGeneration());
+
+            // update the replica with segments_2 from the primary.
+            final SegmentInfos primaryInfos = engine.getLatestSegmentInfos();
+            assertEquals(2, primaryInfos.getGeneration());
+            assertEquals(5, primaryInfos.getVersion());
+            nrtEngine.updateSegments(primaryInfos);
+            assertEquals(4, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(4, nrtEngine.getLatestSegmentInfos().getGeneration());
+            assertEquals(primaryInfos.getVersion(), nrtEngine.getLatestSegmentInfos().getVersion());
+            assertEquals(primaryInfos.getVersion(), nrtEngine.getLastCommittedSegmentInfos().getVersion());
+
+            nrtEngine.close();
+            assertEquals(5, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+        }
+    }
+
+    public void testSimultaneousEngineCloseAndCommit() throws IOException, InterruptedException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            CountDownLatch latch = new CountDownLatch(1);
+            Thread commitThread = new Thread(() -> {
+                try {
+                    nrtEngine.updateSegments(store.readLastCommittedSegmentsInfo());
+                    latch.countDown();
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            });
+            Thread closeThread = new Thread(() -> {
+                try {
+                    latch.await();
+                    nrtEngine.close();
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                } catch (InterruptedException e) {
+                    throw new RuntimeException(e);
+                }
+            });
+            commitThread.start();
+            closeThread.start();
+            commitThread.join();
+            closeThread.join();
+        }
+    }
+
+    public void testUpdateSegments_replicaCommitsFirstReceivedInfos() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            assertEquals(2, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(2, nrtEngine.getLatestSegmentInfos().getGeneration());
+            // bump the latest infos version a couple of times so that we can assert the correct version after commit.
+            engine.getLatestSegmentInfos().changed();
+            engine.getLatestSegmentInfos().changed();
+            assertNotEquals(nrtEngine.getLatestSegmentInfos().getVersion(), engine.getLatestSegmentInfos().getVersion());
+
+            // update replica with the latest primary infos, it will be the same gen, segments_2, ensure it is also committed.
+            final SegmentInfos primaryInfos = engine.getLatestSegmentInfos();
+            assertEquals(2, primaryInfos.getGeneration());
+            nrtEngine.updateSegments(primaryInfos);
+            final SegmentInfos lastCommittedSegmentInfos = nrtEngine.getLastCommittedSegmentInfos();
+            assertEquals(primaryInfos.getVersion(), nrtEngine.getLatestSegmentInfos().getVersion());
+            assertEquals(primaryInfos.getVersion(), lastCommittedSegmentInfos.getVersion());
+        }
+    }
+
+    public void testRefreshOnNRTEngine() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            assertEquals(2, nrtEngine.getLastCommittedSegmentInfos().getGeneration());
+            assertEquals(2, nrtEngine.getLatestSegmentInfos().getGeneration());
+
+            ReferenceManager<OpenSearchDirectoryReader> referenceManager = nrtEngine.getReferenceManager(Engine.SearcherScope.EXTERNAL);
+            OpenSearchDirectoryReader readerBeforeRefresh = referenceManager.acquire();
+
+            nrtEngine.refresh("test refresh");
+            OpenSearchDirectoryReader readerAfterRefresh = referenceManager.acquire();
+
+            // Verify both readers before and after refresh are same and no change in segments
+            assertSame(readerBeforeRefresh, readerAfterRefresh);
+
+        }
+    }
+
+    public void testTrimTranslogOps() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore);
+        ) {
+            List<Engine.Operation> operations = generateHistoryOnReplica(
+                between(1, 100),
+                randomBoolean(),
+                randomBoolean(),
+                randomBoolean()
+            );
+            applyOperations(nrtEngine, operations);
+            Set<Long> seqNos = operations.stream().map(Engine.Operation::seqNo).collect(Collectors.toSet());
+            nrtEngine.ensureOpen();
+            try (
+                Translog.Snapshot snapshot = assertAndGetInternalTranslogManager(nrtEngine.translogManager()).getTranslog().newSnapshot()
+            ) {
+                assertThat(snapshot.totalOperations(), equalTo(operations.size()));
+                assertThat(
+                    TestTranslog.drainSnapshot(snapshot, false).stream().map(Translog.Operation::seqNo).collect(Collectors.toSet()),
+                    equalTo(seqNos)
+                );
+            }
+            nrtEngine.rollTranslogGeneration();
+            nrtEngine.trimOperationsFromTranslog(primaryTerm.get(), NO_OPS_PERFORMED);
+            try (Translog.Snapshot snapshot = getTranslog(engine).newSnapshot()) {
+                assertThat(snapshot.totalOperations(), equalTo(0));
+                assertNull(snapshot.next());
+            }
+        }
+    }
+
+    public void testFlush() throws Exception {
+        // This test asserts that NRTReplication#commitSegmentInfos creates a new commit point with the latest checkpoints
+        // stored in user data.
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore)
+        ) {
+            List<Engine.Operation> operations = generateHistoryOnReplica(between(1, 500), randomBoolean(), randomBoolean(), randomBoolean())
+                .stream()
+                .filter(op -> op.operationType().equals(Engine.Operation.TYPE.INDEX))
+                .collect(Collectors.toList());
+            for (Engine.Operation op : operations) {
+                applyOperation(nrtEngine, op);
+            }
+
+            final SegmentInfos previousInfos = nrtEngine.getLatestSegmentInfos();
+            LocalCheckpointTracker localCheckpointTracker = nrtEngine.getLocalCheckpointTracker();
+            final long maxSeqNo = localCheckpointTracker.getMaxSeqNo();
+            final long processedCheckpoint = localCheckpointTracker.getProcessedCheckpoint();
+            nrtEngine.flush();
+
+            // ensure getLatestSegmentInfos returns an updated infos ref with correct userdata.
+            final SegmentInfos latestSegmentInfos = nrtEngine.getLatestSegmentInfos();
+            assertEquals(previousInfos.getGeneration(), latestSegmentInfos.getLastGeneration());
+            assertEquals(previousInfos.getVersion(), latestSegmentInfos.getVersion());
+            assertEquals(previousInfos.counter, latestSegmentInfos.counter);
+            Map<String, String> userData = latestSegmentInfos.getUserData();
+            assertEquals(processedCheckpoint, localCheckpointTracker.getProcessedCheckpoint());
+            assertEquals(maxSeqNo, Long.parseLong(userData.get(MAX_SEQ_NO)));
+            assertEquals(processedCheckpoint, Long.parseLong(userData.get(LOCAL_CHECKPOINT_KEY)));
+
+            // read infos from store and assert userdata
+            final String lastCommitSegmentsFileName = SegmentInfos.getLastCommitSegmentsFileName(nrtEngineStore.directory());
+            final SegmentInfos committedInfos = SegmentInfos.readCommit(nrtEngineStore.directory(), lastCommitSegmentsFileName);
+            userData = committedInfos.getUserData();
+            assertEquals(processedCheckpoint, Long.parseLong(userData.get(LOCAL_CHECKPOINT_KEY)));
+            assertEquals(maxSeqNo, Long.parseLong(userData.get(MAX_SEQ_NO)));
+
+            try (final GatedCloseable<IndexCommit> indexCommit = nrtEngine.acquireLastIndexCommit(true)) {
+                assertEquals(committedInfos.getGeneration() + 1, indexCommit.get().getGeneration());
+            }
+        }
+    }
+
+    private NRTReplicationEngine buildNrtReplicaEngine(AtomicLong globalCheckpoint, Store store, IndexSettings settings)
+        throws IOException {
+        Lucene.cleanLuceneIndex(store.directory());
+        final Path translogDir = createTempDir();
+        final EngineConfig replicaConfig = config(settings, store, translogDir, NoMergePolicy.INSTANCE, null, null, globalCheckpoint::get);
+        if (Lucene.indexExists(store.directory()) == false) {
+            store.createEmpty(replicaConfig.getIndexSettings().getIndexVersionCreated().luceneVersion);
+            final String translogUuid = Translog.createEmptyTranslog(
+                replicaConfig.getTranslogConfig().getTranslogPath(),
+                SequenceNumbers.NO_OPS_PERFORMED,
+                shardId,
+                primaryTerm.get()
+            );
+            store.associateIndexWithNewTranslog(translogUuid);
+        }
+        return new NRTReplicationEngine(replicaConfig);
+    }
+
+    private NRTReplicationEngine buildNrtReplicaEngine(AtomicLong globalCheckpoint, Store store) throws IOException {
+        return buildNrtReplicaEngine(globalCheckpoint, store, defaultSettings);
+    }
+
+    public void testGetSegmentInfosSnapshotPreservesFilesUntilRelease() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore, INDEX_SETTINGS)
+        ) {
+            // only index 2 docs here, this will create segments _0 and _1 and after forcemerge into _2.
+            final int docCount = 2;
+            List<Engine.Operation> operations = generateHistoryOnReplica(docCount, randomBoolean(), randomBoolean(), randomBoolean());
+            for (Engine.Operation op : operations) {
+                applyOperation(engine, op);
+                applyOperation(nrtEngine, op);
+                // refresh to create a lot of segments.
+                engine.refresh("test");
+            }
+            assertEquals(2, engine.segmentsStats(false, false).getCount());
+            // wipe the nrt directory initially so we can sync with primary.
+            Lucene.cleanLuceneIndex(nrtEngineStore.directory());
+            assertFalse(
+                Arrays.stream(nrtEngineStore.directory().listAll())
+                    .anyMatch(file -> file.equals("write.lock") == false && file.equals("extra0") == false)
+            );
+            for (String file : engine.getLatestSegmentInfos().files(true)) {
+                nrtEngineStore.directory().copyFrom(store.directory(), file, file, IOContext.DEFAULT);
+            }
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+            assertEquals(engine.getLatestSegmentInfos(), nrtEngine.getLatestSegmentInfos());
+            final GatedCloseable<SegmentInfos> snapshot = nrtEngine.getSegmentInfosSnapshot();
+            final Collection<String> replicaSnapshotFiles = snapshot.get().files(false);
+            List<String> replicaFiles = List.of(nrtEngine.store.directory().listAll());
+
+            // merge primary down to 1 segment
+            engine.forceMerge(true, 1, false, false, false, UUIDs.randomBase64UUID());
+            // we expect a 3rd segment to be created after merge.
+            assertEquals(3, engine.segmentsStats(false, false).getCount());
+            final Collection<String> latestPrimaryFiles = engine.getLatestSegmentInfos().files(false);
+
+            // copy new segments in and load reader.
+            for (String file : latestPrimaryFiles) {
+                if (replicaFiles.contains(file) == false) {
+                    nrtEngineStore.directory().copyFrom(store.directory(), file, file, IOContext.DEFAULT);
+                }
+            }
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+
+            replicaFiles = List.of(nrtEngine.store.directory().listAll());
+            assertTrue(replicaFiles.containsAll(replicaSnapshotFiles));
+
+            // close snapshot, files should be cleaned up
+            snapshot.close();
+
+            replicaFiles = List.of(nrtEngine.store.directory().listAll());
+            assertFalse(replicaFiles.containsAll(replicaSnapshotFiles));
+
+            // Ensure we still have all the active files. Note - we exclude the infos file here if we aren't committing
+            // the nrt reader will still reference segments_n-1 after being loaded until a local commit occurs.
+            assertTrue(replicaFiles.containsAll(nrtEngine.getLatestSegmentInfos().files(false)));
+        }
+    }
+
+    public void testRemoveExtraSegmentsOnStartup() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        List<Engine.Operation> operations = generateHistoryOnReplica(2, randomBoolean(), randomBoolean(), randomBoolean());
+        for (Engine.Operation op : operations) {
+            applyOperation(engine, op);
+            // refresh to create a lot of segments.
+            engine.refresh("test");
+        }
+        try (final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());) {
+            nrtEngineStore.createEmpty(Version.LATEST);
+            final Collection<String> extraSegments = engine.getLatestSegmentInfos().files(false);
+            for (String file : extraSegments) {
+                nrtEngineStore.directory().copyFrom(store.directory(), file, file, IOContext.DEFAULT);
+            }
+            List<String> replicaFiles = List.of(nrtEngineStore.directory().listAll());
+            for (String file : extraSegments) {
+                assertTrue(replicaFiles.contains(file));
+            }
+            try (NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore, INDEX_SETTINGS)) {
+                assertUnreferenced(nrtEngine, extraSegments);
+            }
+        }
+    }
+
+    public void testPreserveLatestCommit() throws Exception {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore, INDEX_SETTINGS)
+        ) {
+            final int docCount = 4;
+            List<Engine.Operation> operations = generateHistoryOnReplica(docCount, randomBoolean(), randomBoolean(), randomBoolean());
+            indexOperations(nrtEngine, operations.subList(0, 2));
+            // wipe the nrt directory initially so we can sync with primary.
+            cleanAndCopySegmentsFromPrimary(nrtEngine);
+            SegmentInfos primaryInfos;
+
+            final SegmentInfos lastCommittedSegmentInfos = nrtEngine.getLastCommittedSegmentInfos();
+            final Collection<String> lastCommittedFiles = lastCommittedSegmentInfos.files(true);
+            assertRefCounted(nrtEngine, lastCommittedFiles);
+
+            // get and close a snapshot - this will decref files when closed.
+            final GatedCloseable<SegmentInfos> segmentInfosSnapshot = nrtEngine.getSegmentInfosSnapshot();
+            segmentInfosSnapshot.close();
+            assertRefCounted(nrtEngine, lastCommittedFiles);
+
+            // index more docs and refresh the reader - this will incref/decref files again
+            indexOperations(nrtEngine, operations.subList(2, 4));
+            primaryInfos = engine.getLatestSegmentInfos();
+            copySegments(primaryInfos.files(false), nrtEngine);
+            nrtEngine.updateSegments(primaryInfos);
+
+            // get the additional segments that are only on the reader - not part of a commit.
+            final Collection<String> readerOnlySegments = primaryInfos.files(false);
+            readerOnlySegments.removeAll(lastCommittedFiles);
+            assertRefCounted(nrtEngine, readerOnlySegments);
+            // re-read the last commit from disk here in case the primary engine has flushed.
+            assertRefCounted(nrtEngine, nrtEngine.getLastCommittedSegmentInfos().files(true));
+
+            // flush the primary
+            engine.flush(true, true);
+            final Collection<String> latestPrimaryInfos = engine.getLatestSegmentInfos().files(false);
+            final Collection<String> mergedAwayFiles = nrtEngine.getLastCommittedSegmentInfos().files(false);
+            // remove files still part of latest commit.
+            mergedAwayFiles.removeAll(latestPrimaryInfos);
+            copySegments(latestPrimaryInfos, nrtEngine);
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+            // after flush our original segment_n is removed but some segments may remain.
+            assertUnreferenced(nrtEngine, List.of(lastCommittedSegmentInfos.getSegmentsFileName()));
+            assertUnreferenced(nrtEngine, mergedAwayFiles);
+            // close the engine - ensure we preserved the last commit
+            final SegmentInfos infosBeforeClose = nrtEngine.getLatestSegmentInfos();
+            nrtEngine.close();
+            assertRefCounted(nrtEngine, infosBeforeClose.files(false));
+        }
+    }
+
+    private void assertRefCounted(NRTReplicationEngine nrtEngine, Collection<String> files) throws IOException {
+        List<String> storeFiles = List.of(nrtEngine.store.directory().listAll());
+        for (String file : files) {
+            // refCount for our segments is 2 because they are still active on the reader
+            assertTrue("Expected: " + file + " to be referenced", nrtEngine.replicaFileTracker.refCount(file) >= 1);
+            assertTrue(storeFiles.contains(file));
+        }
+    }
+
+    private void assertUnreferenced(NRTReplicationEngine nrtEngine, Collection<String> files) throws IOException {
+        List<String> storeFiles = List.of(nrtEngine.store.directory().listAll());
+        for (String file : files) {
+            // refCount for our segments is 2 because they are still active on the reader
+            assertEquals("Expected: " + file + " to be unreferenced", 0, nrtEngine.replicaFileTracker.refCount(file));
+            assertFalse(storeFiles.contains(file));
+        }
+    }
+
+    private void cleanAndCopySegmentsFromPrimary(NRTReplicationEngine nrtEngine) throws IOException {
+        Lucene.cleanLuceneIndex(nrtEngine.store.directory());
+        assertFalse(
+            Arrays.stream(nrtEngine.store.directory().listAll())
+                .anyMatch(file -> file.equals("write.lock") == false && file.equals("extra0") == false)
+        );
+        SegmentInfos primaryInfos = engine.getLatestSegmentInfos();
+        copySegments(primaryInfos.files(false), nrtEngine);
+        nrtEngine.updateSegments(primaryInfos);
+    }
+
+    private void indexOperations(NRTReplicationEngine nrtEngine, List<Engine.Operation> operations) throws IOException {
+        for (Engine.Operation op : operations) {
+            applyOperation(engine, op);
+            applyOperation(nrtEngine, op);
+            engine.refresh("test");
+        }
+    }
+
+    public void testDecrefToZeroRemovesFile() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+
+        try (
+            final Store nrtEngineStore = createStore(INDEX_SETTINGS, newDirectory());
+            final NRTReplicationEngine nrtEngine = buildNrtReplicaEngine(globalCheckpoint, nrtEngineStore, INDEX_SETTINGS)
+        ) {
+            Lucene.cleanLuceneIndex(nrtEngineStore.directory());
+            copySegments(engine.getLatestSegmentInfos().files(true), nrtEngine);
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+            final SegmentInfos lastCommittedSegmentInfos = nrtEngine.getLastCommittedSegmentInfos();
+            assertEquals(
+                "Segments_N is incref'd to 1",
+                1,
+                nrtEngine.replicaFileTracker.refCount(lastCommittedSegmentInfos.getSegmentsFileName())
+            );
+            // create a new commit and update infos
+            engine.flush(true, true);
+            nrtEngine.updateSegments(engine.getLatestSegmentInfos());
+            assertEquals(
+                "Segments_N is removed",
+                0,
+                nrtEngine.replicaFileTracker.refCount(lastCommittedSegmentInfos.getSegmentsFileName())
+            );
+            assertFalse(List.of(nrtEngineStore.directory().listAll()).contains(lastCommittedSegmentInfos.getSegmentsFileName()));
+        }
+    }
+
+    private void copySegments(Collection<String> latestPrimaryFiles, Engine nrtEngine) throws IOException {
+        final Store store = nrtEngine.store;
+        final List<String> replicaFiles = List.of(store.directory().listAll());
+        // copy new segments in and load reader.
+        for (String file : latestPrimaryFiles) {
+            if (replicaFiles.contains(file) == false) {
+                store.directory().copyFrom(this.store.directory(), file, file, IOContext.DEFAULT);
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/engine/NRTReplicationReaderManagerTests.java b/server/src/test/java/org/opensearch/index/engine/NRTReplicationReaderManagerTests.java
new file mode 100644
index 0000000000000..d635b38e811c4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/engine/NRTReplicationReaderManagerTests.java
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.engine;
+
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.index.StandardDirectoryReader;
+import org.apache.lucene.util.Version;
+import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.index.store.Store;
+
+import java.io.IOException;
+
+public class NRTReplicationReaderManagerTests extends EngineTestCase {
+
+    public void testCreateNRTreaderManager() throws IOException {
+        try (final Store store = createStore()) {
+            store.createEmpty(Version.LATEST);
+            final DirectoryReader reader = DirectoryReader.open(store.directory());
+            final SegmentInfos initialInfos = ((StandardDirectoryReader) reader).getSegmentInfos();
+            NRTReplicationReaderManager readerManager = new NRTReplicationReaderManager(
+                OpenSearchDirectoryReader.wrap(reader, shardId),
+                (files) -> {},
+                (files) -> {}
+            );
+            assertEquals(initialInfos, readerManager.getSegmentInfos());
+            try (final OpenSearchDirectoryReader acquire = readerManager.acquire()) {
+                assertNull(readerManager.refreshIfNeeded(acquire));
+            }
+
+            // create an updated infos
+            final SegmentInfos infos_2 = readerManager.getSegmentInfos().clone();
+            infos_2.changed();
+
+            readerManager.updateSegments(infos_2);
+            assertEquals(infos_2, readerManager.getSegmentInfos());
+            try (final OpenSearchDirectoryReader acquire = readerManager.acquire()) {
+                final StandardDirectoryReader standardReader = NRTReplicationReaderManager.unwrapStandardReader(acquire);
+                assertEquals(infos_2, standardReader.getSegmentInfos());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/engine/NoOpEngineRecoveryTests.java b/server/src/test/java/org/opensearch/index/engine/NoOpEngineRecoveryTests.java
index 4a895e1efc152..d8b55815b5b05 100644
--- a/server/src/test/java/org/opensearch/index/engine/NoOpEngineRecoveryTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/NoOpEngineRecoveryTests.java
@@ -50,7 +50,7 @@ public void testRecoverFromNoOp() throws IOException {
         for (int i = 0; i < nbDocs; i++) {
             indexDoc(indexShard, "_doc", String.valueOf(i));
         }
-        indexShard.close("test", true);
+        indexShard.close("test", true, false);
 
         final ShardRouting shardRouting = indexShard.routingEntry();
         IndexShard primary = reinitShard(
@@ -58,7 +58,8 @@ public void testRecoverFromNoOp() throws IOException {
             initWithSameId(shardRouting, ExistingStoreRecoverySource.INSTANCE),
             indexShard.indexSettings().getIndexMetadata(),
             NoOpEngine::new,
-            new EngineConfigFactory(indexShard.indexSettings())
+            new EngineConfigFactory(indexShard.indexSettings()),
+            null
         );
         recoverShardFromStore(primary);
         assertEquals(primary.seqNoStats().getMaxSeqNo(), primary.getMaxSeqNoOfUpdatesOrDeletes());
diff --git a/server/src/test/java/org/opensearch/index/engine/NoOpEngineTests.java b/server/src/test/java/org/opensearch/index/engine/NoOpEngineTests.java
index a015443979527..423d246115a9a 100644
--- a/server/src/test/java/org/opensearch/index/engine/NoOpEngineTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/NoOpEngineTests.java
@@ -44,9 +44,9 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.seqno.ReplicationTracker;
@@ -99,7 +99,7 @@ public void testNoopAfterRegularEngine() throws IOException {
             allocationId
         );
         IndexShardRoutingTable table = new IndexShardRoutingTable.Builder(shardId).addShard(routing).build();
-        tracker.updateFromMaster(1L, Collections.singleton(allocationId.getId()), table);
+        tracker.updateFromClusterManager(1L, Collections.singleton(allocationId.getId()), table);
         tracker.activatePrimaryMode(SequenceNumbers.NO_OPS_PERFORMED);
         for (int i = 0; i < docs; i++) {
             ParsedDocument doc = testParsedDocument("" + i, null, testDocumentWithTextField(), B_1, null);
@@ -145,7 +145,7 @@ public void testNoOpEngineStats() throws Exception {
                     if (rarely()) {
                         engine.flush();
                     }
-                    engine.syncTranslog(); // advance persisted local checkpoint
+                    engine.translogManager().syncTranslog(); // advance persisted local checkpoint
                     globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
                 }
 
@@ -154,7 +154,7 @@ public void testNoOpEngineStats() throws Exception {
                         String delId = Integer.toString(i);
                         Engine.DeleteResult result = engine.delete(new Engine.Delete(delId, newUid(delId), primaryTerm.get()));
                         assertTrue(result.isFound());
-                        engine.syncTranslog(); // advance persisted local checkpoint
+                        engine.translogManager().syncTranslog(); // advance persisted local checkpoint
                         globalCheckpoint.set(engine.getPersistedLocalCheckpoint());
                         deletions += 1;
                     }
@@ -203,7 +203,7 @@ public void testTrimUnreferencedTranslogFiles() throws Exception {
             allocationId
         );
         IndexShardRoutingTable table = new IndexShardRoutingTable.Builder(shardId).addShard(routing).build();
-        tracker.updateFromMaster(1L, Collections.singleton(allocationId.getId()), table);
+        tracker.updateFromClusterManager(1L, Collections.singleton(allocationId.getId()), table);
         tracker.activatePrimaryMode(SequenceNumbers.NO_OPS_PERFORMED);
         engine.onSettingsChanged(TimeValue.MINUS_ONE, ByteSizeValue.ZERO, randomNonNegativeLong());
         final int numDocs = scaledRandomIntBetween(10, 3000);
@@ -217,20 +217,24 @@ public void testTrimUnreferencedTranslogFiles() throws Exception {
                 engine.flush();
             }
             if (randomBoolean()) {
-                engine.rollTranslogGeneration();
+                engine.translogManager().rollTranslogGeneration();
             }
         }
         // prevent translog from trimming so we can test trimUnreferencedFiles in NoOpEngine.
-        final Translog.Snapshot snapshot = engine.getTranslog().newSnapshot();
+        engine.ensureOpen();
+        final Translog.Snapshot snapshot = assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().newSnapshot();
         engine.flush(true, true);
         engine.close();
 
         final NoOpEngine noOpEngine = new NoOpEngine(noOpConfig(INDEX_SETTINGS, store, primaryTranslogDir, tracker));
-        assertThat(noOpEngine.getTranslogStats().estimatedNumberOfOperations(), equalTo(totalTranslogOps));
-        noOpEngine.trimUnreferencedTranslogFiles();
-        assertThat(noOpEngine.getTranslogStats().estimatedNumberOfOperations(), equalTo(0));
-        assertThat(noOpEngine.getTranslogStats().getUncommittedOperations(), equalTo(0));
-        assertThat(noOpEngine.getTranslogStats().getTranslogSizeInBytes(), equalTo((long) Translog.DEFAULT_HEADER_SIZE_IN_BYTES));
+        assertThat(noOpEngine.translogManager().getTranslogStats().estimatedNumberOfOperations(), equalTo(totalTranslogOps));
+        noOpEngine.translogManager().trimUnreferencedTranslogFiles();
+        assertThat(noOpEngine.translogManager().getTranslogStats().estimatedNumberOfOperations(), equalTo(0));
+        assertThat(noOpEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(0));
+        assertThat(
+            noOpEngine.translogManager().getTranslogStats().getTranslogSizeInBytes(),
+            equalTo((long) Translog.DEFAULT_HEADER_SIZE_IN_BYTES)
+        );
         snapshot.close();
         noOpEngine.close();
     }
diff --git a/server/src/test/java/org/opensearch/index/engine/ReadOnlyEngineTests.java b/server/src/test/java/org/opensearch/index/engine/ReadOnlyEngineTests.java
index 2106c5e1067fb..01e74500c770b 100644
--- a/server/src/test/java/org/opensearch/index/engine/ReadOnlyEngineTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/ReadOnlyEngineTests.java
@@ -32,19 +32,30 @@
 package org.opensearch.index.engine;
 
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexFormatTooOldException;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.tests.util.LuceneTestCase;
+import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.TranslogStats;
+import org.opensearch.test.FeatureFlagSetter;
+import org.opensearch.test.IndexSettingsModule;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Function;
@@ -58,7 +69,7 @@ public class ReadOnlyEngineTests extends EngineTestCase {
 
     public void testReadOnlyEngine() throws Exception {
         IOUtils.close(engine, store);
-        Engine readOnlyEngine = null;
+        ReadOnlyEngine readOnlyEngine = null;
         final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
         try (Store store = createStore()) {
             EngineConfig config = config(defaultSettings, store, createTempDir(), newMergePolicy(), null, null, globalCheckpoint::get);
@@ -93,13 +104,13 @@ public void testReadOnlyEngine() throws Exception {
                     }
                     globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
                 }
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
                 globalCheckpoint.set(randomLongBetween(globalCheckpoint.get(), engine.getPersistedLocalCheckpoint()));
                 engine.flush();
                 readOnlyEngine = new ReadOnlyEngine(
                     engine.engineConfig,
                     engine.getSeqNoStats(globalCheckpoint.get()),
-                    engine.getTranslogStats(),
+                    engine.translogManager().getTranslogStats(),
                     false,
                     Function.identity(),
                     true
@@ -107,6 +118,7 @@ public void testReadOnlyEngine() throws Exception {
                 lastSeqNoStats = engine.getSeqNoStats(globalCheckpoint.get());
                 lastDocIds = getDocIds(engine, true);
                 assertThat(readOnlyEngine.getPersistedLocalCheckpoint(), equalTo(lastSeqNoStats.getLocalCheckpoint()));
+                assertThat((readOnlyEngine).getProcessedLocalCheckpoint(), equalTo(readOnlyEngine.getPersistedLocalCheckpoint()));
                 assertThat(readOnlyEngine.getSeqNoStats(globalCheckpoint.get()).getMaxSeqNo(), equalTo(lastSeqNoStats.getMaxSeqNo()));
                 assertThat(getDocIds(readOnlyEngine, false), equalTo(lastDocIds));
                 for (int i = 0; i < numDocs; i++) {
@@ -131,6 +143,7 @@ public void testReadOnlyEngine() throws Exception {
                 IOUtils.close(external, internal);
                 // the locked down engine should still point to the previous commit
                 assertThat(readOnlyEngine.getPersistedLocalCheckpoint(), equalTo(lastSeqNoStats.getLocalCheckpoint()));
+                assertThat((readOnlyEngine).getProcessedLocalCheckpoint(), equalTo(readOnlyEngine.getPersistedLocalCheckpoint()));
                 assertThat(readOnlyEngine.getSeqNoStats(globalCheckpoint.get()).getMaxSeqNo(), equalTo(lastSeqNoStats.getMaxSeqNo()));
                 assertThat(getDocIds(readOnlyEngine, false), equalTo(lastDocIds));
                 try (Engine.GetResult getResult = readOnlyEngine.get(get, readOnlyEngine::acquireSearcher)) {
@@ -139,9 +152,12 @@ public void testReadOnlyEngine() throws Exception {
             }
             // Close and reopen the main engine
             try (InternalEngine recoveringEngine = new InternalEngine(config)) {
-                recoveringEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+                TranslogHandler translogHandler = createTranslogHandler(config.getIndexSettings(), recoveringEngine);
+                recoveringEngine.translogManager()
+                    .recoverFromTranslog(translogHandler, recoveringEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
                 // the locked down engine should still point to the previous commit
                 assertThat(readOnlyEngine.getPersistedLocalCheckpoint(), equalTo(lastSeqNoStats.getLocalCheckpoint()));
+                assertThat((readOnlyEngine).getProcessedLocalCheckpoint(), equalTo(readOnlyEngine.getPersistedLocalCheckpoint()));
                 assertThat(readOnlyEngine.getSeqNoStats(globalCheckpoint.get()).getMaxSeqNo(), equalTo(lastSeqNoStats.getMaxSeqNo()));
                 assertThat(getDocIds(readOnlyEngine, false), equalTo(lastDocIds));
             }
@@ -178,7 +194,7 @@ public void testEnsureMaxSeqNoIsEqualToGlobalCheckpoint() throws IOException {
                     );
                     maxSeqNo = engine.getProcessedLocalCheckpoint();
                 }
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
                 globalCheckpoint.set(engine.getPersistedLocalCheckpoint() - 1);
                 engine.flushAndClose();
 
@@ -223,6 +239,46 @@ public void testReadOnly() throws IOException {
         }
     }
 
+    public void testReadOldIndices() throws Exception {
+        IOUtils.close(engine, store);
+        // The index has one document in it, so the checkpoint cannot be NO_OPS_PERFORMED
+        final AtomicLong globalCheckpoint = new AtomicLong(0);
+        final String pathToTestIndex = "/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip";
+        Path tmp = createTempDir();
+        TestUtil.unzip(getClass().getResourceAsStream(pathToTestIndex), tmp);
+        FeatureFlagSetter.set(FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY);
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                .build()
+        );
+        try (Store store = createStore(newFSDirectory(tmp))) {
+            EngineConfig config = config(indexSettings, store, createTempDir(), newMergePolicy(), null, null, globalCheckpoint::get);
+            try (ReadOnlyEngine readOnlyEngine = new ReadOnlyEngine(config, null, new TranslogStats(), true, Function.identity(), true)) {
+                assertVisibleCount(readOnlyEngine, 1, false);
+            }
+        }
+    }
+
+    public void testReadOldIndicesFailure() throws IOException {
+        IOUtils.close(engine, store);
+        // The index has one document in it, so the checkpoint cannot be NO_OPS_PERFORMED
+        final AtomicLong globalCheckpoint = new AtomicLong(0);
+        final String pathToTestIndex = "/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip";
+        Path tmp = createTempDir();
+        TestUtil.unzip(getClass().getResourceAsStream(pathToTestIndex), tmp);
+        try (Store store = createStore(newFSDirectory(tmp))) {
+            EngineConfig config = config(defaultSettings, store, createTempDir(), newMergePolicy(), null, null, globalCheckpoint::get);
+            try {
+                new ReadOnlyEngine(config, null, new TranslogStats(), true, Function.identity(), true);
+            } catch (UncheckedIOException e) {
+                assertEquals(IndexFormatTooOldException.class, e.getCause().getClass());
+            }
+        }
+    }
+
     /**
      * Test that {@link ReadOnlyEngine#verifyEngineBeforeIndexClosing()} never fails
      * whatever the value of the global checkpoint to check is.
@@ -274,12 +330,13 @@ public void testRecoverFromTranslogAppliesNoOperations() throws IOException {
                     }
                     globalCheckpoint.set(i);
                 }
-                engine.syncTranslog();
+                engine.translogManager().syncTranslog();
                 engine.flushAndClose();
             }
             try (ReadOnlyEngine readOnlyEngine = new ReadOnlyEngine(config, null, null, true, Function.identity(), true)) {
-                final TranslogHandler translogHandler = new TranslogHandler(xContentRegistry(), config.getIndexSettings());
-                readOnlyEngine.recoverFromTranslog(translogHandler, randomNonNegativeLong());
+                final TranslogHandler translogHandler = new TranslogHandler(xContentRegistry(), config.getIndexSettings(), readOnlyEngine);
+                readOnlyEngine.translogManager()
+                    .recoverFromTranslog(translogHandler, readOnlyEngine.getProcessedLocalCheckpoint(), randomNonNegativeLong());
 
                 assertThat(translogHandler.appliedOperations(), equalTo(0L));
             }
@@ -324,23 +381,26 @@ public void testTranslogStats() throws IOException {
                 }
 
                 assertThat(
-                    engine.getTranslogStats().estimatedNumberOfOperations(),
+                    engine.translogManager().getTranslogStats().estimatedNumberOfOperations(),
                     equalTo(softDeletesEnabled ? uncommittedDocs : numDocs)
                 );
-                assertThat(engine.getTranslogStats().getUncommittedOperations(), equalTo(uncommittedDocs));
-                assertThat(engine.getTranslogStats().getTranslogSizeInBytes(), greaterThan(0L));
-                assertThat(engine.getTranslogStats().getUncommittedSizeInBytes(), greaterThan(0L));
-                assertThat(engine.getTranslogStats().getEarliestLastModifiedAge(), greaterThan(0L));
+                assertThat(engine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(uncommittedDocs));
+                assertThat(engine.translogManager().getTranslogStats().getTranslogSizeInBytes(), greaterThan(0L));
+                assertThat(engine.translogManager().getTranslogStats().getUncommittedSizeInBytes(), greaterThan(0L));
+                assertThat(engine.translogManager().getTranslogStats().getEarliestLastModifiedAge(), greaterThan(0L));
 
                 engine.flush(true, true);
             }
 
             try (ReadOnlyEngine readOnlyEngine = new ReadOnlyEngine(config, null, null, true, Function.identity(), true)) {
-                assertThat(readOnlyEngine.getTranslogStats().estimatedNumberOfOperations(), equalTo(softDeletesEnabled ? 0 : numDocs));
-                assertThat(readOnlyEngine.getTranslogStats().getUncommittedOperations(), equalTo(0));
-                assertThat(readOnlyEngine.getTranslogStats().getTranslogSizeInBytes(), greaterThan(0L));
-                assertThat(readOnlyEngine.getTranslogStats().getUncommittedSizeInBytes(), greaterThan(0L));
-                assertThat(readOnlyEngine.getTranslogStats().getEarliestLastModifiedAge(), greaterThan(0L));
+                assertThat(
+                    readOnlyEngine.translogManager().getTranslogStats().estimatedNumberOfOperations(),
+                    equalTo(softDeletesEnabled ? 0 : numDocs)
+                );
+                assertThat(readOnlyEngine.translogManager().getTranslogStats().getUncommittedOperations(), equalTo(0));
+                assertThat(readOnlyEngine.translogManager().getTranslogStats().getTranslogSizeInBytes(), greaterThan(0L));
+                assertThat(readOnlyEngine.translogManager().getTranslogStats().getUncommittedSizeInBytes(), greaterThan(0L));
+                assertThat(readOnlyEngine.translogManager().getTranslogStats().getEarliestLastModifiedAge(), greaterThan(0L));
             }
         }
     }
diff --git a/server/src/test/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicyTests.java b/server/src/test/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicyTests.java
index a8279ed908779..34c0dd3478578 100644
--- a/server/src/test/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicyTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/RecoverySourcePruneMergePolicyTests.java
@@ -49,14 +49,15 @@
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.ShuffleForcedMergePolicy;
 import org.apache.lucene.index.StandardDirectoryReader;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.InfoStream;
 import org.apache.lucene.tests.util.NullInfoStream;
+import org.apache.lucene.util.InfoStream;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -89,8 +90,9 @@ public void testPruneAll() throws IOException {
                 writer.forceMerge(1);
                 writer.commit();
                 try (DirectoryReader reader = DirectoryReader.open(writer)) {
+                    StoredFields storedFields = reader.storedFields();
                     for (int i = 0; i < reader.maxDoc(); i++) {
-                        Document document = reader.document(i);
+                        Document document = storedFields.document(i);
                         assertEquals(1, document.getFields().size());
                         assertEquals("source", document.getFields().get(0).name());
                     }
@@ -157,11 +159,12 @@ public void testPruneSome() throws IOException {
                 writer.forceMerge(1);
                 writer.commit();
                 try (DirectoryReader reader = DirectoryReader.open(writer)) {
+                    StoredFields storedFields = reader.storedFields();
                     assertEquals(1, reader.leaves().size());
                     NumericDocValues extra_source = reader.leaves().get(0).reader().getNumericDocValues("extra_source");
                     assertNotNull(extra_source);
                     for (int i = 0; i < reader.maxDoc(); i++) {
-                        Document document = reader.document(i);
+                        Document document = storedFields.document(i);
                         Set<String> collect = document.getFields().stream().map(IndexableField::name).collect(Collectors.toSet());
                         assertTrue(collect.contains("source"));
                         assertTrue(collect.contains("even"));
@@ -197,11 +200,12 @@ public void testPruneNone() throws IOException {
                 writer.forceMerge(1);
                 writer.commit();
                 try (DirectoryReader reader = DirectoryReader.open(writer)) {
+                    StoredFields storedFields = reader.storedFields();
                     assertEquals(1, reader.leaves().size());
                     NumericDocValues extra_source = reader.leaves().get(0).reader().getNumericDocValues("extra_source");
                     assertNotNull(extra_source);
                     for (int i = 0; i < reader.maxDoc(); i++) {
-                        Document document = reader.document(i);
+                        Document document = storedFields.document(i);
                         Set<String> collect = document.getFields().stream().map(IndexableField::name).collect(Collectors.toSet());
                         assertTrue(collect.contains("source"));
                         assertTrue(collect.contains("extra_source"));
diff --git a/server/src/test/java/org/opensearch/index/engine/SegmentTests.java b/server/src/test/java/org/opensearch/index/engine/SegmentTests.java
index 7b0072f83f9cb..840bfe37b979d 100644
--- a/server/src/test/java/org/opensearch/index/engine/SegmentTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/SegmentTests.java
@@ -33,14 +33,14 @@
 package org.opensearch.index.engine;
 
 import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedNumericSelector;
 import org.apache.lucene.search.SortedNumericSortField;
-import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.search.SortedSetSelector;
-import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.util.Version;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataImplTestCase.java b/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataImplTestCase.java
index 9be0a738441e5..2b44e759f4ff9 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataImplTestCase.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataImplTestCase.java
@@ -39,9 +39,10 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.search.MultiValueMode;
 
 import java.io.IOException;
@@ -144,6 +145,27 @@ public void testSingleValueAllSet() throws Exception {
         }
     }
 
+    public void testWideSortField() throws Exception {
+        if (this instanceof NoOrdinalsStringFieldDataTests || this instanceof PagedBytesStringFieldDataTests) {
+            return; // Numeric types are not supported there.
+        }
+        // integer to long widening should happen
+        IndexFieldData<?> indexFieldData = getForField("int", "value");
+        SortField sortField = indexFieldData.wideSortField(null, MultiValueMode.MIN, null, false);
+        assertTrue(((SortedNumericSortField) sortField).getNumericType() == SortField.Type.LONG);
+
+        // long to long no widening should happen
+        indexFieldData = getForField("long", "value");
+        sortField = indexFieldData.wideSortField(null, MultiValueMode.MIN, null, false);
+        assertTrue(((SortedNumericSortField) sortField).getNumericType() == SortField.Type.LONG);
+
+        // float to float no widening should happen
+        indexFieldData = getForField("float", "value");
+        sortField = indexFieldData.wideSortField(null, MultiValueMode.MIN, null, false);
+        assertTrue(((SortedNumericSortField) sortField).getNumericType() == SortField.Type.FLOAT);
+
+    }
+
     protected abstract void fillSingleValueWithMissing() throws Exception;
 
     public void assertValues(SortedBinaryDocValues values, int docId, BytesRef... actualValues) throws IOException {
diff --git a/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataTestCase.java b/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataTestCase.java
index 69be53dc1016b..63c74b3cfa64f 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataTestCase.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/AbstractFieldDataTestCase.java
@@ -46,11 +46,13 @@
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.ContentPath;
+import org.opensearch.index.mapper.FlatObjectFieldMapper;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -59,12 +61,11 @@
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.TextFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.junit.After;
 import org.junit.Before;
 
@@ -142,6 +143,8 @@ public <IFD extends IndexFieldData<?>> IFD getForField(String type, String field
                 .fieldType();
         } else if (type.equals("geo_point")) {
             fieldType = new GeoPointFieldMapper.Builder(fieldName).docValues(docValues).build(context).fieldType();
+        } else if (type.equals("flat_object")) {
+            fieldType = new FlatObjectFieldMapper.Builder(fieldName).docValues(docValues).build(context).fieldType();
         } else if (type.equals("binary")) {
             fieldType = new BinaryFieldMapper.Builder(fieldName, docValues).build(context).fieldType();
         } else {
diff --git a/server/src/test/java/org/opensearch/index/fielddata/AbstractStringFieldDataTestCase.java b/server/src/test/java/org/opensearch/index/fielddata/AbstractStringFieldDataTestCase.java
index 763ee59a385a2..3aa698260686d 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/AbstractStringFieldDataTestCase.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/AbstractStringFieldDataTestCase.java
@@ -52,20 +52,21 @@
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopFieldDocs;
+import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.join.QueryBitSetProducer;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.search.join.ToParentBlockJoinQuery;
+import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
-import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.UnicodeUtil;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
 import org.opensearch.index.fielddata.ordinals.GlobalOrdinalsIndexFieldData;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.MultiValueMode;
 
 import java.io.IOException;
@@ -340,7 +341,13 @@ public void testSortMissing(boolean first, boolean reverse) throws IOException {
             randomBoolean() ? numDocs : randomIntBetween(10, numDocs),
             new Sort(sortField)
         );
-        assertEquals(numDocs, topDocs.totalHits.value);
+        // As of Lucene 9.0.0, totalHits may be a lower bound
+        if (topDocs.totalHits.relation == TotalHits.Relation.EQUAL_TO) {
+            assertEquals(numDocs, topDocs.totalHits.value);
+        } else {
+            assertTrue(1000 <= topDocs.totalHits.value);
+            assertTrue(numDocs >= topDocs.totalHits.value);
+        }
         BytesRef previousValue = first ? null : reverse ? UnicodeUtil.BIG_TERM : new BytesRef();
         for (int i = 0; i < topDocs.scoreDocs.length; ++i) {
             final String docValue = searcher.doc(topDocs.scoreDocs[i].doc).get("value");
diff --git a/server/src/test/java/org/opensearch/index/fielddata/BinaryDVFieldDataTests.java b/server/src/test/java/org/opensearch/index/fielddata/BinaryDVFieldDataTests.java
index 071366d7c3345..ce5b93b34a89e 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/BinaryDVFieldDataTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/BinaryDVFieldDataTests.java
@@ -34,12 +34,11 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.ParsedDocument;
 import org.opensearch.index.mapper.SourceToParse;
@@ -54,19 +53,18 @@ protected boolean hasDocValues() {
     }
 
     public void testDocValue() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("test")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "binary")
-                .field("doc_values", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("test")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "binary")
+            .field("doc_values", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         final DocumentMapper mapper = mapperService.documentMapperParser().parse("test", new CompressedXContent(mapping));
 
@@ -81,16 +79,16 @@ public void testDocValue() throws Exception {
             doc.endArray();
         }
         doc.endObject();
-        ParsedDocument d = mapper.parse(new SourceToParse("test", "1", BytesReference.bytes(doc), XContentType.JSON));
+        ParsedDocument d = mapper.parse(new SourceToParse("test", "1", BytesReference.bytes(doc), MediaTypeRegistry.JSON));
         writer.addDocument(d.rootDoc());
 
         BytesRef bytes1 = randomBytes();
         doc = XContentFactory.jsonBuilder().startObject().field("field", bytes1.bytes, bytes1.offset, bytes1.length).endObject();
-        d = mapper.parse(new SourceToParse("test", "2", BytesReference.bytes(doc), XContentType.JSON));
+        d = mapper.parse(new SourceToParse("test", "2", BytesReference.bytes(doc), MediaTypeRegistry.JSON));
         writer.addDocument(d.rootDoc());
 
         doc = XContentFactory.jsonBuilder().startObject().endObject();
-        d = mapper.parse(new SourceToParse("test", "3", BytesReference.bytes(doc), XContentType.JSON));
+        d = mapper.parse(new SourceToParse("test", "3", BytesReference.bytes(doc), MediaTypeRegistry.JSON));
         writer.addDocument(d.rootDoc());
 
         // test remove duplicate value
@@ -106,7 +104,7 @@ public void testDocValue() throws Exception {
             doc.endArray();
         }
         doc.endObject();
-        d = mapper.parse(new SourceToParse("test", "4", BytesReference.bytes(doc), XContentType.JSON));
+        d = mapper.parse(new SourceToParse("test", "4", BytesReference.bytes(doc), MediaTypeRegistry.JSON));
         writer.addDocument(d.rootDoc());
 
         IndexFieldData<?> indexFieldData = getForField("field");
diff --git a/server/src/test/java/org/opensearch/index/fielddata/FieldDataCacheTests.java b/server/src/test/java/org/opensearch/index/fielddata/FieldDataCacheTests.java
index a5e07c4fba373..a49391013dcd4 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/FieldDataCacheTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/FieldDataCacheTests.java
@@ -44,15 +44,15 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.fielddata.plain.AbstractLeafOrdinalsFieldData;
 import org.opensearch.index.fielddata.plain.PagedBytesIndexFieldData;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
 import org.opensearch.index.mapper.TextFieldMapper;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.support.CoreValuesSourceType;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.FieldMaskingReader;
+import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
 
diff --git a/server/src/test/java/org/opensearch/index/fielddata/FieldDataStatsTests.java b/server/src/test/java/org/opensearch/index/fielddata/FieldDataStatsTests.java
index 157b1719a883c..296f760095ed1 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/FieldDataStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/FieldDataStatsTests.java
@@ -34,7 +34,7 @@
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.FieldMemoryStatsTests;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/fielddata/GeoShapeValueTests.java b/server/src/test/java/org/opensearch/index/fielddata/GeoShapeValueTests.java
new file mode 100644
index 0000000000000..b2d3729e53553
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/fielddata/GeoShapeValueTests.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.tests.util.TestUtil;
+import org.opensearch.common.geo.GeoShapeDocValue;
+import org.opensearch.geometry.Point;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class GeoShapeValueTests extends OpenSearchTestCase {
+
+    public void testMissingGeoShapeValue() throws IOException {
+        final int numDocs = TestUtil.nextInt(random(), 1, 100);
+        final GeoShapeDocValue[][] values = new GeoShapeDocValue[numDocs][];
+
+        for (int i = 0; i < numDocs; ++i) {
+            values[i] = new GeoShapeDocValue[1];
+            int number = TestUtil.nextInt(random(), 1, 2);
+            if (number == 1) {
+                values[i][0] = GeoShapeDocValue.createGeometryDocValue(new Point(randomDouble() * 90, randomDouble() * 180));
+            } else {
+                values[i][0] = null;
+            }
+
+        }
+        final GeoShapeValue asGeoValues = new GeoShapeValue() {
+            int doc;
+
+            @Override
+            public boolean advanceExact(int docId) {
+                doc = docId;
+                return values[doc][0] != null;
+            }
+
+            @Override
+            public GeoShapeDocValue nextValue() {
+                return values[doc][0];
+            }
+
+        };
+        final Point missing = new Point(randomDouble() * 90, randomDouble() * 180);
+        final GeoShapeValue withMissingReplaced = new GeoShapeValue.MissingGeoShapeValue(asGeoValues, missing);
+        final GeoShapeDocValue missingValue = GeoShapeDocValue.createGeometryDocValue(missing);
+        for (int i = 0; i < numDocs; i++) {
+            assertTrue(withMissingReplaced.advanceExact(i));
+            if (values[i][0] != null) {
+                assertEquals(values[i][0], withMissingReplaced.nextValue());
+            } else {
+                assertEquals(missingValue, withMissingReplaced.nextValue());
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java b/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
index d2f9125be996a..bcdca2236d3f3 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
@@ -43,9 +43,10 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.util.Accountable;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.fielddata.plain.SortedNumericIndexFieldData;
 import org.opensearch.index.fielddata.plain.SortedSetOrdinalsIndexFieldData;
@@ -56,17 +57,15 @@
 import org.opensearch.index.mapper.Mapper.BuilderContext;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.TextFieldMapper;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.lookup.SearchLookup;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.IndexSettingsModule;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
-import org.mockito.Mockito;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -74,6 +73,8 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Supplier;
 
+import org.mockito.Mockito;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -327,10 +328,9 @@ private void doTestRequireDocValues(MappedFieldType ft) {
             if (ft.hasDocValues()) {
                 ifds.getForField(ft, "test", () -> { throw new UnsupportedOperationException(); }); // no exception
             } else {
-                IllegalArgumentException e = expectThrows(
-                    IllegalArgumentException.class,
-                    () -> ifds.getForField(ft, "test", () -> { throw new UnsupportedOperationException(); })
-                );
+                IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> ifds.getForField(ft, "test", () -> {
+                    throw new UnsupportedOperationException();
+                }));
                 assertThat(e.getMessage(), containsString("doc values"));
             }
         } finally {
@@ -370,6 +370,22 @@ public void testRequireDocValuesOnDoubles() {
         );
     }
 
+    public void testRequireDocValuesOnUnsignedLongs() {
+        doTestRequireDocValues(new NumberFieldMapper.NumberFieldType("field", NumberFieldMapper.NumberType.UNSIGNED_LONG));
+        doTestRequireDocValues(
+            new NumberFieldMapper.NumberFieldType(
+                "field",
+                NumberFieldMapper.NumberType.UNSIGNED_LONG,
+                true,
+                false,
+                false,
+                false,
+                null,
+                Collections.emptyMap()
+            )
+        );
+    }
+
     public void testRequireDocValuesOnBools() {
         doTestRequireDocValues(new BooleanFieldMapper.BooleanFieldType("field"));
         doTestRequireDocValues(new BooleanFieldMapper.BooleanFieldType("field", true, false, false, null, Collections.emptyMap()));
diff --git a/server/src/test/java/org/opensearch/index/fielddata/ScriptDocValuesGeoPointsTests.java b/server/src/test/java/org/opensearch/index/fielddata/ScriptDocValuesGeoPointsTests.java
index 2ca5facc608ed..7af96344dd0eb 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/ScriptDocValuesGeoPointsTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/ScriptDocValuesGeoPointsTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.fielddata;
 
-import org.opensearch.index.fielddata.ScriptDocValues.GeoPoints;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
+import org.opensearch.index.fielddata.ScriptDocValues.GeoPoints;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/fielddata/plain/HalfFloatFielddataTests.java b/server/src/test/java/org/opensearch/index/fielddata/plain/HalfFloatFielddataTests.java
index be631cc311b2a..b5d936910b84c 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/plain/HalfFloatFielddataTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/plain/HalfFloatFielddataTests.java
@@ -39,8 +39,8 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.store.Directory;
-import org.opensearch.core.internal.io.IOUtils;
 import org.apache.lucene.tests.util.TestUtil;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.fielddata.FieldData;
 import org.opensearch.index.fielddata.SortedNumericDoubleValues;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/index/fieldstats/FieldStatsProviderRefreshTests.java b/server/src/test/java/org/opensearch/index/fieldstats/FieldStatsProviderRefreshTests.java
index 35c16c9954622..16ce40d588a1b 100644
--- a/server/src/test/java/org/opensearch/index/fieldstats/FieldStatsProviderRefreshTests.java
+++ b/server/src/test/java/org/opensearch/index/fieldstats/FieldStatsProviderRefreshTests.java
@@ -38,9 +38,9 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.indices.IndicesRequestCache;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
diff --git a/server/src/test/java/org/opensearch/index/get/DocumentFieldTests.java b/server/src/test/java/org/opensearch/index/get/DocumentFieldTests.java
index ed80e736ae5f9..254a609f7b9e5 100644
--- a/server/src/test/java/org/opensearch/index/get/DocumentFieldTests.java
+++ b/server/src/test/java/org/opensearch/index/get/DocumentFieldTests.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.index.get;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.collect.Map;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.test.OpenSearchTestCase;
@@ -49,10 +50,11 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -60,13 +62,13 @@ public class DocumentFieldTests extends OpenSearchTestCase {
 
     public void testToXContent() {
         DocumentField documentField = new DocumentField("field", Arrays.asList("value1", "value2"));
-        String output = Strings.toString(documentField);
+        String output = Strings.toString(MediaTypeRegistry.JSON, documentField);
         assertEquals("{\"field\":[\"value1\",\"value2\"]}", output);
     }
 
     public void testEqualsAndHashcode() {
         checkEqualsAndHashCode(
-            randomDocumentField(XContentType.JSON).v1(),
+            randomDocumentField(MediaTypeRegistry.JSON).v1(),
             DocumentFieldTests::copyDocumentField,
             DocumentFieldTests::mutateDocumentField
         );
@@ -102,7 +104,7 @@ private static DocumentField copyDocumentField(DocumentField documentField) {
     private static DocumentField mutateDocumentField(DocumentField documentField) {
         List<Supplier<DocumentField>> mutations = new ArrayList<>();
         mutations.add(() -> new DocumentField(randomUnicodeOfCodepointLength(15), documentField.getValues()));
-        mutations.add(() -> new DocumentField(documentField.getName(), randomDocumentField(XContentType.JSON).v1().getValues()));
+        mutations.add(() -> new DocumentField(documentField.getName(), randomDocumentField(MediaTypeRegistry.JSON).v1().getValues()));
         final int index = randomFrom(0, 1);
         final DocumentField randomCandidate = mutations.get(index).get();
         if (!documentField.equals(randomCandidate)) {
@@ -115,12 +117,12 @@ private static DocumentField mutateDocumentField(DocumentField documentField) {
         }
     }
 
-    public static Tuple<DocumentField, DocumentField> randomDocumentField(XContentType xContentType) {
-        return randomDocumentField(xContentType, randomBoolean(), fieldName -> false);  // don't exclude any meta-fields
+    public static Tuple<DocumentField, DocumentField> randomDocumentField(MediaType mediaType) {
+        return randomDocumentField(mediaType, randomBoolean(), fieldName -> false);  // don't exclude any meta-fields
     }
 
     public static Tuple<DocumentField, DocumentField> randomDocumentField(
-        XContentType xContentType,
+        MediaType mediaType,
         boolean isMetafield,
         Predicate<String> excludeMetaFieldFilter
     ) {
@@ -143,7 +145,7 @@ public static Tuple<DocumentField, DocumentField> randomDocumentField(
             switch (randomIntBetween(0, 2)) {
                 case 0:
                     String fieldName = randomAlphaOfLengthBetween(3, 10);
-                    Tuple<List<Object>, List<Object>> tuple = RandomObjects.randomStoredFieldValues(random(), xContentType);
+                    Tuple<List<Object>, List<Object>> tuple = RandomObjects.randomStoredFieldValues(random(), mediaType);
                     DocumentField input = new DocumentField(fieldName, tuple.v1());
                     DocumentField expected = new DocumentField(fieldName, tuple.v2());
                     return Tuple.tuple(input, expected);
diff --git a/server/src/test/java/org/opensearch/index/get/GetResultTests.java b/server/src/test/java/org/opensearch/index/get/GetResultTests.java
index 9519b83fa54b1..64b14744a40d2 100644
--- a/server/src/test/java/org/opensearch/index/get/GetResultTests.java
+++ b/server/src/test/java/org/opensearch/index/get/GetResultTests.java
@@ -32,21 +32,21 @@
 
 package org.opensearch.index.get;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IndexFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.SourceFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.VersionFieldMapper;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
@@ -62,8 +62,8 @@
 
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.index.get.DocumentFieldTests.randomDocumentField;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
@@ -106,7 +106,7 @@ public void testToXContent() throws IOException {
                 singletonMap("field1", new DocumentField("field1", singletonList("value1"))),
                 singletonMap("field1", new DocumentField("metafield", singletonList("metavalue")))
             );
-            String output = Strings.toString(getResult);
+            String output = Strings.toString(MediaTypeRegistry.JSON, getResult);
             assertEquals(
                 "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":1,\"_seq_no\":0,\"_primary_term\":1,"
                     + "\"metafield\":\"metavalue\",\"found\":true,\"_source\":{ \"field1\" : \"value1\", \"field2\":\"value2\"},"
@@ -116,7 +116,7 @@ public void testToXContent() throws IOException {
         }
         {
             GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);
-            String output = Strings.toString(getResult);
+            String output = Strings.toString(MediaTypeRegistry.JSON, getResult);
             assertEquals("{\"_index\":\"index\",\"_id\":\"id\",\"found\":false}", output);
         }
     }
@@ -174,7 +174,7 @@ public void testToXContentEmbedded() throws IOException {
             null
         );
 
-        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
+        BytesReference originalBytes = toXContentEmbedded(getResult, MediaTypeRegistry.JSON, false);
         assertEquals(
             "{\"_seq_no\":0,\"_primary_term\":1,\"found\":true,\"_source\":{\"foo\":\"bar\",\"baz\":[\"baz_0\",\"baz_1\"]},"
                 + "\"fields\":{\"foo\":[\"bar\"],\"baz\":[\"baz_0\",\"baz_1\"]}}",
@@ -185,7 +185,7 @@ public void testToXContentEmbedded() throws IOException {
     public void testToXContentEmbeddedNotFound() throws IOException {
         GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);
 
-        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
+        BytesReference originalBytes = toXContentEmbedded(getResult, MediaTypeRegistry.JSON, false);
         assertEquals("{\"found\":false}", originalBytes.utf8ToString());
     }
 
@@ -197,7 +197,7 @@ public void testSerializationNotFound() throws IOException {
         getResult.writeTo(out);
         getResult = new GetResult(out.bytes().streamInput());
 
-        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
+        BytesReference originalBytes = toXContentEmbedded(getResult, MediaTypeRegistry.JSON, false);
         assertEquals("{\"found\":false}", originalBytes.utf8ToString());
     }
 
@@ -213,7 +213,11 @@ public void testGetSourceAsBytes() {
     }
 
     public void testEqualsAndHashcode() {
-        checkEqualsAndHashCode(randomGetResult(XContentType.JSON).v1(), GetResultTests::copyGetResult, GetResultTests::mutateGetResult);
+        checkEqualsAndHashCode(
+            randomGetResult(MediaTypeRegistry.JSON).v1(),
+            GetResultTests::copyGetResult,
+            GetResultTests::mutateGetResult
+        );
     }
 
     public static GetResult copyGetResult(GetResult getResult) {
@@ -306,14 +310,14 @@ public static GetResult mutateGetResult(GetResult getResult) {
                 getResult.getVersion(),
                 getResult.isExists(),
                 getResult.internalSourceRef(),
-                randomDocumentFields(XContentType.JSON, randomBoolean()).v1(),
+                randomDocumentFields(MediaTypeRegistry.JSON, randomBoolean()).v1(),
                 null
             )
         );
         return randomFrom(mutations).get();
     }
 
-    public static Tuple<GetResult, GetResult> randomGetResult(XContentType xContentType) {
+    public static Tuple<GetResult, GetResult> randomGetResult(MediaType mediaType) {
         final String index = randomAlphaOfLengthBetween(3, 10);
         final String type = randomAlphaOfLengthBetween(3, 10);
         final String id = randomAlphaOfLengthBetween(3, 10);
@@ -335,11 +339,11 @@ public static Tuple<GetResult, GetResult> randomGetResult(XContentType xContentT
                 source = RandomObjects.randomSource(random());
             }
             if (randomBoolean()) {
-                Tuple<Map<String, DocumentField>, Map<String, DocumentField>> tuple = randomDocumentFields(xContentType, false);
+                Tuple<Map<String, DocumentField>, Map<String, DocumentField>> tuple = randomDocumentFields(mediaType, false);
                 docFields = tuple.v1();
                 expectedDocFields = tuple.v2();
 
-                tuple = randomDocumentFields(xContentType, true);
+                tuple = randomDocumentFields(mediaType, true);
                 metaFields = tuple.v1();
                 expectedMetaFields = tuple.v2();
             }
@@ -365,22 +369,21 @@ public static Tuple<GetResult, GetResult> randomGetResult(XContentType xContentT
     }
 
     public static Tuple<Map<String, DocumentField>, Map<String, DocumentField>> randomDocumentFields(
-        XContentType xContentType,
+        MediaType mediaType,
         boolean isMetaFields
     ) {
         int numFields = isMetaFields ? randomIntBetween(1, 3) : randomIntBetween(2, 10);
         Map<String, DocumentField> fields = new HashMap<>(numFields);
         Map<String, DocumentField> expectedFields = new HashMap<>(numFields);
         // As we are using this to construct a GetResult object that already contains
-        // index, type, id, version, seqNo, and source fields, we need to exclude them from random fields
-        Predicate<String> excludeMetaFieldFilter = field -> field.equals(TypeFieldMapper.NAME)
-            || field.equals(IndexFieldMapper.NAME)
+        // index, id, version, seqNo, and source fields, we need to exclude them from random fields
+        Predicate<String> excludeMetaFieldFilter = field -> field.equals(IndexFieldMapper.NAME)
             || field.equals(IdFieldMapper.NAME)
             || field.equals(VersionFieldMapper.NAME)
             || field.equals(SourceFieldMapper.NAME)
             || field.equals(SeqNoFieldMapper.NAME);
         while (fields.size() < numFields) {
-            Tuple<DocumentField, DocumentField> tuple = randomDocumentField(xContentType, isMetaFields, excludeMetaFieldFilter);
+            Tuple<DocumentField, DocumentField> tuple = randomDocumentField(mediaType, isMetaFields, excludeMetaFieldFilter);
             DocumentField getField = tuple.v1();
             DocumentField expectedGetField = tuple.v2();
             if (fields.putIfAbsent(getField.getName(), getField) == null) {
@@ -390,8 +393,7 @@ public static Tuple<Map<String, DocumentField>, Map<String, DocumentField>> rand
         return Tuple.tuple(fields, expectedFields);
     }
 
-    private static BytesReference toXContentEmbedded(GetResult getResult, XContentType xContentType, boolean humanReadable)
-        throws IOException {
-        return XContentHelper.toXContent(getResult::toXContentEmbedded, xContentType, humanReadable);
+    private static BytesReference toXContentEmbedded(GetResult getResult, MediaType mediaType, boolean humanReadable) throws IOException {
+        return org.opensearch.core.xcontent.XContentHelper.toXContent(getResult::toXContentEmbedded, mediaType, humanReadable);
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/AllFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/AllFieldMapperTests.java
deleted file mode 100644
index 625cfbb81f8bc..0000000000000
--- a/server/src/test/java/org/opensearch/index/mapper/AllFieldMapperTests.java
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.mapper;
-
-import org.opensearch.common.Strings;
-import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.index.IndexService;
-import org.opensearch.index.mapper.MapperService.MergeReason;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
-
-public class AllFieldMapperTests extends OpenSearchSingleNodeTestCase {
-
-    @Override
-    protected boolean forbidPrivateIndexSettings() {
-        return false;
-    }
-
-    public void testUpdateDefaultSearchAnalyzer() throws Exception {
-        IndexService indexService = createIndex(
-            "test",
-            Settings.builder()
-                .put("index.analysis.analyzer.default_search.type", "custom")
-                .put("index.analysis.analyzer.default_search.tokenizer", "standard")
-                .build()
-        );
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("_doc").endObject().endObject());
-        indexService.mapperService().merge("_doc", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
-        assertEquals(mapping, indexService.mapperService().documentMapper().mapping().toString());
-    }
-
-}
diff --git a/server/src/test/java/org/opensearch/index/mapper/BinaryFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/BinaryFieldMapperTests.java
index 7c2df0fd80f2b..87b5ad3434944 100644
--- a/server/src/test/java/org/opensearch/index/mapper/BinaryFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/BinaryFieldMapperTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -119,11 +119,11 @@ public void testStoredValue() throws IOException {
 
         // case 2: a value that looks compressed: this used to fail in 1.x
         BytesStreamOutput out = new BytesStreamOutput();
-        try (OutputStream compressed = CompressorFactory.COMPRESSOR.threadLocalOutputStream(out)) {
+        try (OutputStream compressed = CompressorRegistry.defaultCompressor().threadLocalOutputStream(out)) {
             new BytesArray(binaryValue1).writeTo(compressed);
         }
         final byte[] binaryValue2 = BytesReference.toBytes(out.bytes());
-        assertTrue(CompressorFactory.isCompressed(new BytesArray(binaryValue2)));
+        assertTrue(CompressorRegistry.isCompressed(new BytesArray(binaryValue2)));
 
         for (byte[] value : Arrays.asList(binaryValue1, binaryValue2)) {
             ParsedDocument doc = mapperService.documentMapper().parse(source(b -> b.field("field", value)));
diff --git a/server/src/test/java/org/opensearch/index/mapper/BooleanFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/BooleanFieldMapperTests.java
index b9955d2079f29..8dec03a353d16 100644
--- a/server/src/test/java/org/opensearch/index/mapper/BooleanFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/BooleanFieldMapperTests.java
@@ -40,10 +40,9 @@
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.ParseContext.Document;
 
 import java.io.IOException;
@@ -62,7 +61,7 @@ protected void minimalMapping(XContentBuilder b) throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     protected void registerParameters(ParameterChecker checker) throws IOException {
@@ -105,7 +104,7 @@ public void testSerialization() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject();
         mapper.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        assertEquals("{\"field\":{\"type\":\"boolean\"}}", Strings.toString(builder));
+        assertEquals("{\"field\":{\"type\":\"boolean\"}}", builder.toString());
 
         // now change some parameters
         defaultMapper = createDocumentMapper(fieldMapping(b -> {
@@ -117,7 +116,7 @@ public void testSerialization() throws IOException {
         builder = XContentFactory.jsonBuilder().startObject();
         mapper.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        assertEquals("{\"field\":{\"type\":\"boolean\",\"doc_values\":false,\"null_value\":true}}", Strings.toString(builder));
+        assertEquals("{\"field\":{\"type\":\"boolean\",\"doc_values\":false,\"null_value\":true}}", builder.toString());
     }
 
     public void testParsesBooleansStrict() throws IOException {
diff --git a/server/src/test/java/org/opensearch/index/mapper/CompletionFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/CompletionFieldMapperTests.java
index b116cff8bb8f3..b1785f5d7b14c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/CompletionFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/CompletionFieldMapperTests.java
@@ -46,12 +46,13 @@
 import org.apache.lucene.util.CharsRefBuilder;
 import org.apache.lucene.util.automaton.Operations;
 import org.apache.lucene.util.automaton.RegExp;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -186,7 +187,7 @@ public void testCompletionAnalyzerSettings() throws Exception {
         assertEquals(
             "{\"field\":{\"type\":\"completion\",\"analyzer\":\"simple\",\"search_analyzer\":\"standard\","
                 + "\"preserve_separators\":false,\"preserve_position_increments\":true,\"max_input_length\":50}}",
-            Strings.toString(fieldMapper)
+            Strings.toString(MediaTypeRegistry.JSON, fieldMapper)
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/CopyToMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/CopyToMapperTests.java
index ab1bfd1bab16b..b274cf28429e8 100644
--- a/server/src/test/java/org/opensearch/index/mapper/CopyToMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/CopyToMapperTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.hamcrest.Matchers;
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/DataStreamFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/DataStreamFieldMapperTests.java
index 374b7ac9a5271..8fdc1b8a62be6 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DataStreamFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DataStreamFieldMapperTests.java
@@ -8,11 +8,10 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import static org.hamcrest.Matchers.containsString;
@@ -21,16 +20,15 @@
 public class DataStreamFieldMapperTests extends OpenSearchSingleNodeTestCase {
 
     public void testDefaultTimestampField() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("_data_stream_timestamp")
-                .field("enabled", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("_data_stream_timestamp")
+            .field("enabled", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertDataStreamFieldMapper(mapping, "@timestamp");
     }
@@ -38,37 +36,35 @@ public void testDefaultTimestampField() throws Exception {
     public void testCustomTimestampField() throws Exception {
         String timestampFieldName = "timestamp_" + randomAlphaOfLength(5);
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("_data_stream_timestamp")
-                .field("enabled", true)
-                .startObject("timestamp_field")
-                .field("name", timestampFieldName)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("_data_stream_timestamp")
+            .field("enabled", true)
+            .startObject("timestamp_field")
+            .field("name", timestampFieldName)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertDataStreamFieldMapper(mapping, timestampFieldName);
     }
 
     public void testDeeplyNestedCustomTimestampField() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("_data_stream_timestamp")
-                .field("enabled", true)
-                .startObject("timestamp_field")
-                .field("name", "event.meta.created_at")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("_data_stream_timestamp")
+            .field("enabled", true)
+            .startObject("timestamp_field")
+            .field("name", "event.meta.created_at")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper mapper = createIndex("test").mapperService()
             .merge("_doc", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
@@ -87,7 +83,7 @@ public void testDeeplyNestedCustomTimestampField() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         assertThat(doc.rootDoc().getFields("event.meta.created_at").length, equalTo(2));
@@ -107,7 +103,7 @@ public void testDeeplyNestedCustomTimestampField() throws Exception {
                             .endObject()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         });
@@ -129,7 +125,7 @@ private void assertDataStreamFieldMapper(String mapping, String timestampFieldNa
                 BytesReference.bytes(
                     XContentFactory.jsonBuilder().startObject().field(timestampFieldName, "2020-12-06T11:04:05.000Z").endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -147,7 +143,7 @@ private void assertDataStreamFieldMapper(String mapping, String timestampFieldNa
                     BytesReference.bytes(
                         XContentFactory.jsonBuilder().startObject().field("invalid-field-name", "2020-12-06T11:04:05.000Z").endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         });
@@ -168,7 +164,7 @@ private void assertDataStreamFieldMapper(String mapping, String timestampFieldNa
                             .array(timestampFieldName, "2020-12-06T11:04:05.000Z", "2020-12-07T11:04:05.000Z")
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         });
diff --git a/server/src/test/java/org/opensearch/index/mapper/DateFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/DateFieldMapperTests.java
index cdc5c9567e581..2afd6773b15d4 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DateFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DateFieldMapperTests.java
@@ -34,10 +34,8 @@
 
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.bootstrap.JavaVersion;
-import org.opensearch.common.collect.List;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.termvectors.TermVectorsService;
 import org.opensearch.search.DocValueFormat;
 
@@ -45,6 +43,7 @@
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
+import java.util.List;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.notNullValue;
@@ -84,7 +83,7 @@ public void testExistsQueryDocValuesDisabled() throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     public void testDefaults() throws Exception {
@@ -186,8 +185,6 @@ public void testChangeFormat() throws IOException {
     }
 
     public void testChangeLocale() throws IOException {
-        assumeTrue("need java 9 for testing ", JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0);
-
         DocumentMapper mapper = createDocumentMapper(
             fieldMapping(b -> b.field("type", "date").field("format", "E, d MMM yyyy HH:mm:ss Z").field("locale", "de"))
         );
diff --git a/server/src/test/java/org/opensearch/index/mapper/DateFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/DateFieldTypeTests.java
index 085343f4ff2f7..ae4de156b1cd3 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DateFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DateFieldTypeTests.java
@@ -40,9 +40,10 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.SortedNumericDocValues;
-import org.apache.lucene.sandbox.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
 import org.opensearch.Version;
@@ -52,7 +53,7 @@
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.common.time.DateMathParser;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.fielddata.LeafNumericFieldData;
@@ -260,7 +261,10 @@ public void testRangeQuery() throws IOException {
             LongPoint.newRangeQuery("field", instant1, instant2),
             SortedNumericDocValuesField.newSlowRangeQuery("field", instant1, instant2)
         );
-        assertEquals(expected, ft.rangeQuery(date1, date2, true, true, null, null, null, context).rewrite(new MultiReader()));
+        assertEquals(
+            expected,
+            ft.rangeQuery(date1, date2, true, true, null, null, null, context).rewrite(new IndexSearcher(new MultiReader()))
+        );
 
         instant1 = nowInMillis;
         instant2 = instant1 + 100;
diff --git a/server/src/test/java/org/opensearch/index/mapper/DocCountFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/DocCountFieldMapperTests.java
new file mode 100644
index 0000000000000..634276a34b9af
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/DocCountFieldMapperTests.java
@@ -0,0 +1,83 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.index.DocValuesType;
+import org.apache.lucene.index.IndexableField;
+
+import static org.hamcrest.Matchers.containsString;
+
+public class DocCountFieldMapperTests extends MapperServiceTestCase {
+
+    private static final String CONTENT_TYPE = DocCountFieldMapper.CONTENT_TYPE;
+    private static final String DOC_COUNT_FIELD = DocCountFieldMapper.NAME;
+
+    /**
+     * Test parsing field mapping and adding simple field
+     */
+    public void testParseValue() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        ParsedDocument doc = mapper.parse(source(b -> b.field("foo", 500).field(CONTENT_TYPE, 100)));
+
+        IndexableField field = doc.rootDoc().getField(DOC_COUNT_FIELD);
+        assertEquals(100L, field.numericValue());
+        assertEquals(DocValuesType.NUMERIC, field.fieldType().docValuesType());
+        assertEquals(1, doc.rootDoc().getFields(DOC_COUNT_FIELD).length);
+    }
+
+    public void testInvalidDocument_NegativeDocCount() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        Exception e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.field(CONTENT_TYPE, -100))));
+        assertThat(e.getCause().getMessage(), containsString("Field [_doc_count] must be a positive integer"));
+    }
+
+    public void testInvalidDocument_ZeroDocCount() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        Exception e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.field(CONTENT_TYPE, 0))));
+        assertThat(e.getCause().getMessage(), containsString("Field [_doc_count] must be a positive integer"));
+    }
+
+    public void testInvalidDocument_NonNumericDocCount() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        Exception e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.field(CONTENT_TYPE, "foo"))));
+        assertThat(
+            e.getCause().getMessage(),
+            containsString("Failed to parse object: expecting token of type [VALUE_NUMBER] but found [VALUE_STRING]")
+        );
+    }
+
+    public void testInvalidDocument_FractionalDocCount() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        Exception e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.field(CONTENT_TYPE, 100.23))));
+        assertThat(e.getCause().getMessage(), containsString("100.23 cannot be converted to Long without data loss"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/DocCountFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/DocCountFieldTypeTests.java
new file mode 100644
index 0000000000000..4961736ea933c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/DocCountFieldTypeTests.java
@@ -0,0 +1,69 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.search.DocValuesFieldExistsQuery;
+import org.opensearch.index.query.QueryShardException;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+public class DocCountFieldTypeTests extends FieldTypeTestCase {
+
+    public void testTermQuery() {
+        MappedFieldType ft = new DocCountFieldMapper.DocCountFieldType();
+        QueryShardException e = expectThrows(QueryShardException.class, () -> ft.termQuery(10L, randomMockShardContext()));
+        assertEquals("Field [_doc_count] of type [_doc_count] is not searchable", e.getMessage());
+    }
+
+    public void testRangeQuery() {
+        MappedFieldType ft = new DocCountFieldMapper.DocCountFieldType();
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> ft.rangeQuery(null, null, randomBoolean(), randomBoolean(), null, null, null, null)
+        );
+        assertEquals("Field [_doc_count] of type [_doc_count] does not support range queries", e.getMessage());
+    }
+
+    public void testExistsQuery() {
+        MappedFieldType ft = new DocCountFieldMapper.DocCountFieldType();
+        assertTrue(ft.existsQuery(randomMockShardContext()) instanceof DocValuesFieldExistsQuery);
+    }
+
+    public void testFetchSourceValue() throws IOException {
+        MappedFieldType fieldType = new DocCountFieldMapper.DocCountFieldType();
+        assertEquals(Arrays.asList(14L), fetchSourceValue(fieldType, 14));
+        assertEquals(Arrays.asList(14L), fetchSourceValue(fieldType, "14"));
+        assertEquals(Arrays.asList(1L), fetchSourceValue(fieldType, ""));
+        assertEquals(Arrays.asList(1L), fetchSourceValue(fieldType, null));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/DocumentMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/DocumentMapperTests.java
index 9a1113d04a6f6..fa6ef72552faf 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DocumentMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DocumentMapperTests.java
@@ -266,12 +266,7 @@ public void testMergeMetaForIndexTemplate() throws IOException {
             b.endObject();
         }));
 
-        Map<String, Object> expected = org.opensearch.common.collect.Map.of(
-            "field",
-            "value",
-            "object",
-            org.opensearch.common.collect.Map.of("field1", "value1", "field2", "value2")
-        );
+        Map<String, Object> expected = Map.of("field", "value", "object", Map.of("field1", "value1", "field2", "value2"));
         assertThat(initMapper.meta(), equalTo(expected));
 
         DocumentMapper updatedMapper = createDocumentMapper(fieldMapping(b -> b.field("type", "text")));
@@ -293,12 +288,7 @@ public void testMergeMetaForIndexTemplate() throws IOException {
         }));
         mergedMapper = mergedMapper.merge(updatedMapper.mapping(), MergeReason.INDEX_TEMPLATE);
 
-        expected = org.opensearch.common.collect.Map.of(
-            "field",
-            "value",
-            "object",
-            org.opensearch.common.collect.Map.of("field1", "value1", "field2", "new_value", "field3", "value3")
-        );
+        expected = Map.of("field", "value", "object", Map.of("field1", "value1", "field2", "new_value", "field3", "value3"));
         assertThat(mergedMapper.meta(), equalTo(expected));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/DocumentParserTests.java b/server/src/test/java/org/opensearch/index/mapper/DocumentParserTests.java
index 0ad8dc3f138e0..ecab9da8c6b6c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DocumentParserTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DocumentParserTests.java
@@ -36,12 +36,11 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.plugins.Plugin;
@@ -248,14 +247,14 @@ public void testNestedHaveIdAndTypeFields() throws Exception {
         assertNotNull(result.docs().get(0).getField(IdFieldMapper.NAME));
         assertEquals(Uid.encodeId("1"), result.docs().get(0).getField(IdFieldMapper.NAME).binaryValue());
         assertEquals(IdFieldMapper.Defaults.NESTED_FIELD_TYPE, result.docs().get(0).getField(IdFieldMapper.NAME).fieldType());
-        assertNotNull(result.docs().get(0).getField(TypeFieldMapper.NAME));
-        assertEquals("__foo", result.docs().get(0).getField(TypeFieldMapper.NAME).stringValue());
+        assertNotNull(result.docs().get(0).getField(NestedPathFieldMapper.NAME));
+        assertEquals("foo", result.docs().get(0).getField(NestedPathFieldMapper.NAME).stringValue());
         assertEquals("value1", result.docs().get(0).getField("foo.bar").binaryValue().utf8ToString());
         // Root document:
         assertNotNull(result.docs().get(1).getField(IdFieldMapper.NAME));
         assertEquals(Uid.encodeId("1"), result.docs().get(1).getField(IdFieldMapper.NAME).binaryValue());
         assertEquals(IdFieldMapper.Defaults.FIELD_TYPE, result.docs().get(1).getField(IdFieldMapper.NAME).fieldType());
-        assertNull(result.docs().get(1).getField(TypeFieldMapper.NAME));
+        assertNull(result.docs().get(1).getField(NestedPathFieldMapper.NAME));
         assertEquals("value2", result.docs().get(1).getField("baz").binaryValue().utf8ToString());
     }
 
@@ -1063,7 +1062,7 @@ public void testParseToJsonAndParse() throws Exception {
         // reparse it
         DocumentMapper builtDocMapper = createDocumentMapper(MapperService.SINGLE_MAPPING_NAME, builtMapping);
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/opensearch/index/mapper/simple/test1.json"));
-        Document doc = builtDocMapper.parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = builtDocMapper.parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         assertThat(doc.getBinaryValue(builtDocMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
         assertThat(doc.get(builtDocMapper.mappers().getMapper("name.first").name()), equalTo("fred"));
     }
@@ -1075,7 +1074,7 @@ public void testSimpleParser() throws Exception {
         assertThat((String) docMapper.meta().get("param1"), equalTo("value1"));
 
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/opensearch/index/mapper/simple/test1.json"));
-        Document doc = docMapper.parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = docMapper.parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         assertThat(doc.getBinaryValue(docMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
         assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("fred"));
     }
@@ -1084,7 +1083,7 @@ public void testSimpleParserNoTypeNoId() throws Exception {
         String mapping = copyToStringFromClasspath("/org/opensearch/index/mapper/simple/test-mapping.json");
         DocumentMapper docMapper = createDocumentMapper(MapperService.SINGLE_MAPPING_NAME, mapping);
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/opensearch/index/mapper/simple/test1-notype-noid.json"));
-        Document doc = docMapper.parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = docMapper.parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         assertThat(doc.getBinaryValue(docMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
         assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("fred"));
     }
@@ -1106,7 +1105,7 @@ public void testNoDocumentSent() throws Exception {
         BytesReference json = new BytesArray("".getBytes(StandardCharsets.UTF_8));
         MapperParsingException e = expectThrows(
             MapperParsingException.class,
-            () -> docMapper.parse(new SourceToParse("test", "1", json, XContentType.JSON))
+            () -> docMapper.parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON))
         );
         assertThat(e.getMessage(), equalTo("failed to parse, document is empty"));
     }
@@ -1469,21 +1468,172 @@ public void testDynamicDottedFieldNameWithFieldAlias() throws Exception {
     }
 
     public void testTypeless() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper mapper = createDocumentMapper(MapperService.SINGLE_MAPPING_NAME, mapping);
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("foo", "1234")));
         assertNull(doc.dynamicMappingsUpdate()); // no update since we reused the existing type
     }
+
+    public void testDocumentContainsDeepNestedFieldParsing() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        ParsedDocument doc = mapper.parse(source(b -> {
+            b.startObject("inner1");
+            {
+                b.field("inner1_field1", "inner1_value1");
+                b.startObject("inner2");
+                {
+                    b.startObject("inner3");
+                    {
+                        b.field("inner3_field1", "inner3_value1");
+                        b.field("inner3_field2", "inner3_value2");
+                    }
+                    b.endObject();
+                }
+                b.endObject();
+            }
+            b.endObject();
+        }));
+
+        Mapping update = doc.dynamicMappingsUpdate();
+        assertNotNull(update); // dynamic mapping update
+
+        Mapper objMapper = update.root().getMapper("inner1");
+        Mapper inner1_field1_mapper = ((ObjectMapper) objMapper).getMapper("inner1_field1");
+        assertNotNull(inner1_field1_mapper);
+        Mapper inner2_mapper = ((ObjectMapper) objMapper).getMapper("inner2");
+        assertNotNull(inner2_mapper);
+        Mapper inner3_mapper = ((ObjectMapper) inner2_mapper).getMapper("inner3");
+        assertNotNull(inner3_mapper);
+        assertThat(doc.rootDoc().get("inner1.inner2.inner3.inner3_field1"), equalTo("inner3_value1"));
+    }
+
+    public void testDocumentContainsDeepNestedFieldParsingFail() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        long depth_limit = MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING.getDefault(Settings.EMPTY);
+        MapperParsingException e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> {
+            for (int i = 1; i <= depth_limit; i++) {
+                b.startObject("inner" + i);
+            }
+            b.field("inner_field", "inner_value");
+            for (int i = 1; i <= depth_limit; i++) {
+                b.endObject();
+            }
+        })));
+
+        // check that parsing succeeds with valid doc
+        // after throwing exception
+        ParsedDocument doc = mapper.parse(source(b -> {
+            b.startObject("inner1");
+            {
+                b.startObject("inner2");
+                {
+                    b.startObject("inner3");
+                    {
+                        b.field("inner3_field1", "inner3_value1");
+                    }
+                    b.endObject();
+                }
+                b.endObject();
+            }
+            b.endObject();
+        }));
+
+        Mapping update = doc.dynamicMappingsUpdate();
+        assertNotNull(update); // dynamic mapping update
+        Mapper objMapper = update.root().getMapper("inner1");
+        Mapper inner2_mapper = ((ObjectMapper) objMapper).getMapper("inner2");
+        assertNotNull(inner2_mapper);
+        Mapper inner3_mapper = ((ObjectMapper) inner2_mapper).getMapper("inner3");
+        assertNotNull(inner3_mapper);
+        assertThat(doc.rootDoc().get("inner1.inner2.inner3.inner3_field1"), equalTo("inner3_value1"));
+    }
+
+    public void testDocumentContainsDeepNestedFieldParsingShouldFail() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> { b.field("type", "nested"); }));
+        long depth_limit = MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING.getDefault(Settings.EMPTY);
+        MapperParsingException e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> {
+            b.startObject("field");
+            b.startArray("inner");
+            for (int i = 1; i <= depth_limit; i++) {
+                b.startArray();
+            }
+            b.startArray().value(0).value(0).endArray();
+            for (int i = 1; i <= depth_limit; i++) {
+                b.endArray();
+            }
+            b.endArray();
+            b.endObject();
+        })));
+        // check parsing success for nested array within allowed depth limit
+        ParsedDocument doc = mapper.parse(source(b -> {
+            b.startObject("field");
+            b.startArray("inner");
+            for (int i = 1; i < depth_limit - 1; i++) {
+                b.startArray();
+            }
+            b.startArray().value(0).value(0).endArray();
+            for (int i = 1; i < depth_limit - 1; i++) {
+                b.endArray();
+            }
+            b.endArray();
+            b.endObject();
+        }
+
+        ));
+        Mapping update = doc.dynamicMappingsUpdate();
+        assertNotNull(update); // dynamic mapping update
+
+    }
+
+    // Test nesting upto max allowed depth with combination of nesting in object and array
+    // object -> array -> object -> array ....
+    public void testDocumentDeepNestedObjectAndArrayCombination() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {}));
+        long depth_limit = MapperService.INDEX_MAPPING_DEPTH_LIMIT_SETTING.getDefault(Settings.EMPTY);
+        MapperParsingException e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> {
+            for (int i = 1; i < depth_limit; i++) {
+                b.startArray("foo" + 1);
+                b.startObject();
+            }
+            b.startArray("bar");
+            b.startArray().value(0).value(0).endArray();
+            b.endArray();
+            for (int i = 1; i < depth_limit; i++) {
+                b.endObject();
+                b.endArray();
+            }
+        })));
+
+        // check parsing success for nested array within allowed depth limit
+        ParsedDocument doc = mapper.parse(source(b -> {
+            for (int i = 1; i < depth_limit - 1; i++) {
+                b.startArray("foo" + 1);
+                b.startObject();
+            }
+            b.startArray("bar");
+            b.startArray().value(0).value(0).endArray();
+            b.endArray();
+            for (int i = 1; i < depth_limit - 1; i++) {
+                b.endObject();
+                b.endArray();
+            }
+        }
+
+        ));
+        Mapping update = doc.dynamicMappingsUpdate();
+        assertNotNull(update); // dynamic mapping update
+
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/DynamicMappingTests.java b/server/src/test/java/org/opensearch/index/mapper/DynamicMappingTests.java
index dee5db4e31253..6cf9600f74341 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DynamicMappingTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DynamicMappingTests.java
@@ -32,10 +32,11 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -183,7 +184,7 @@ public void testField() throws Exception {
         assertEquals(
             "{\"_doc\":{\"properties\":{\"foo\":{\"type\":\"text\",\"fields\":"
                 + "{\"keyword\":{\"type\":\"keyword\",\"ignore_above\":256}}}}}}",
-            Strings.toString(doc.dynamicMappingsUpdate())
+            Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate())
         );
     }
 
@@ -199,9 +200,9 @@ public void testIncremental() throws Exception {
         }));
         assertNotNull(doc.dynamicMappingsUpdate());
 
-        assertThat(Strings.toString(doc.dynamicMappingsUpdate()), containsString("{\"bar\":"));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()), containsString("{\"bar\":"));
         // field is NOT in the update
-        assertThat(Strings.toString(doc.dynamicMappingsUpdate()), not(containsString("{\"field\":")));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()), not(containsString("{\"field\":")));
     }
 
     public void testIntroduceTwoFields() throws Exception {
@@ -213,8 +214,8 @@ public void testIntroduceTwoFields() throws Exception {
         }));
 
         assertNotNull(doc.dynamicMappingsUpdate());
-        assertThat(Strings.toString(doc.dynamicMappingsUpdate()), containsString("\"foo\":{"));
-        assertThat(Strings.toString(doc.dynamicMappingsUpdate()), containsString("\"bar\":{"));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()), containsString("\"foo\":{"));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()), containsString("\"bar\":{"));
     }
 
     public void testObject() throws Exception {
@@ -229,7 +230,7 @@ public void testObject() throws Exception {
 
         assertNotNull(doc.dynamicMappingsUpdate());
         assertThat(
-            Strings.toString(doc.dynamicMappingsUpdate()),
+            Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()),
             containsString("{\"foo\":{\"properties\":{\"bar\":{\"properties\":{\"baz\":{\"type\":\"text\"")
         );
     }
@@ -240,7 +241,7 @@ public void testArray() throws Exception {
         ParsedDocument doc = mapper.parse(source(b -> b.startArray("foo").value("bar").value("baz").endArray()));
 
         assertNotNull(doc.dynamicMappingsUpdate());
-        assertThat(Strings.toString(doc.dynamicMappingsUpdate()), containsString("{\"foo\":{\"type\":\"text\""));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()), containsString("{\"foo\":{\"type\":\"text\""));
     }
 
     public void testInnerDynamicMapping() throws Exception {
@@ -256,7 +257,7 @@ public void testInnerDynamicMapping() throws Exception {
 
         assertNotNull(doc.dynamicMappingsUpdate());
         assertThat(
-            Strings.toString(doc.dynamicMappingsUpdate()),
+            Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate()),
             containsString("{\"field\":{\"properties\":{\"bar\":{\"properties\":{\"baz\":{\"type\":\"text\"")
         );
     }
@@ -276,7 +277,7 @@ public void testComplexArray() throws Exception {
         assertEquals(
             "{\"_doc\":{\"properties\":{\"foo\":{\"properties\":{\"bar\":{\"type\":\"text\",\"fields\":{"
                 + "\"keyword\":{\"type\":\"keyword\",\"ignore_above\":256}}},\"baz\":{\"type\":\"long\"}}}}}}",
-            Strings.toString(doc.dynamicMappingsUpdate())
+            Strings.toString(MediaTypeRegistry.JSON, doc.dynamicMappingsUpdate())
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/DynamicTemplateTests.java b/server/src/test/java/org/opensearch/index/mapper/DynamicTemplateTests.java
index a21ccfd0c52cf..3d53f3fbebd87 100644
--- a/server/src/test/java/org/opensearch/index/mapper/DynamicTemplateTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/DynamicTemplateTests.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DynamicTemplate.XContentFieldType;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -107,7 +106,7 @@ public void testSerialization() throws Exception {
         DynamicTemplate template = DynamicTemplate.parse("my_template", templateDef);
         XContentBuilder builder = JsonXContent.contentBuilder();
         template.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals("{\"match_mapping_type\":\"string\",\"mapping\":{\"store\":true}}", Strings.toString(builder));
+        assertEquals("{\"match_mapping_type\":\"string\",\"mapping\":{\"store\":true}}", builder.toString());
 
         // name-based template
         templateDef = new HashMap<>();
@@ -117,7 +116,7 @@ public void testSerialization() throws Exception {
         template = DynamicTemplate.parse("my_template", templateDef);
         builder = JsonXContent.contentBuilder();
         template.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals("{\"match\":\"*name\",\"unmatch\":\"first_name\",\"mapping\":{\"store\":true}}", Strings.toString(builder));
+        assertEquals("{\"match\":\"*name\",\"unmatch\":\"first_name\",\"mapping\":{\"store\":true}}", builder.toString());
 
         // path-based template
         templateDef = new HashMap<>();
@@ -127,7 +126,7 @@ public void testSerialization() throws Exception {
         template = DynamicTemplate.parse("my_template", templateDef);
         builder = JsonXContent.contentBuilder();
         template.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals("{\"path_match\":\"*name\",\"path_unmatch\":\"first_name\",\"mapping\":{\"store\":true}}", Strings.toString(builder));
+        assertEquals("{\"path_match\":\"*name\",\"path_unmatch\":\"first_name\",\"mapping\":{\"store\":true}}", builder.toString());
 
         // regex matching
         templateDef = new HashMap<>();
@@ -137,6 +136,6 @@ public void testSerialization() throws Exception {
         template = DynamicTemplate.parse("my_template", templateDef);
         builder = JsonXContent.contentBuilder();
         template.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals("{\"match\":\"^a$\",\"match_pattern\":\"regex\",\"mapping\":{\"store\":true}}", Strings.toString(builder));
+        assertEquals("{\"match\":\"^a$\",\"match_pattern\":\"regex\",\"mapping\":{\"store\":true}}", builder.toString());
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/ExternalMapperPlugin.java b/server/src/test/java/org/opensearch/index/mapper/ExternalMapperPlugin.java
index dc179acaca324..147ad63e0c4f3 100644
--- a/server/src/test/java/org/opensearch/index/mapper/ExternalMapperPlugin.java
+++ b/server/src/test/java/org/opensearch/index/mapper/ExternalMapperPlugin.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.index.mapper;
 
+import org.opensearch.plugins.MapperPlugin;
+import org.opensearch.plugins.Plugin;
+
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
-import org.opensearch.plugins.MapperPlugin;
-import org.opensearch.plugins.Plugin;
-
 public class ExternalMapperPlugin extends Plugin implements MapperPlugin {
 
     public static final String EXTERNAL = "external";
diff --git a/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperTests.java
index 7a10646b5497a..1952e455b1c78 100644
--- a/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentFactory;
 
 import java.io.IOException;
@@ -40,22 +39,21 @@
 public class FieldAliasMapperTests extends MapperServiceTestCase {
 
     public void testParsing() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("_doc")
-                .startObject("properties")
-                .startObject("alias-field")
-                .field("type", "alias")
-                .field("path", "concrete-field")
-                .endObject()
-                .startObject("concrete-field")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("_doc")
+            .startObject("properties")
+            .startObject("alias-field")
+            .field("type", "alias")
+            .field("path", "concrete-field")
+            .endObject()
+            .startObject("concrete-field")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper mapper = createDocumentMapper("_doc", mapping);
         assertEquals(mapping, mapper.mappingSource().toString());
     }
diff --git a/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperValidationTests.java b/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperValidationTests.java
index 7ffc22f92d839..92de2707078f3 100644
--- a/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperValidationTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/FieldAliasMapperValidationTests.java
@@ -220,7 +220,7 @@ private static ObjectMapper createObjectMapper(String name) {
             ObjectMapper.Nested.NO,
             ObjectMapper.Dynamic.FALSE,
             emptyMap(),
-            Settings.EMPTY
+            SETTINGS
         );
     }
 
@@ -232,7 +232,7 @@ private static ObjectMapper createNestedObjectMapper(String name) {
             ObjectMapper.Nested.newNested(),
             ObjectMapper.Dynamic.FALSE,
             emptyMap(),
-            Settings.EMPTY
+            SETTINGS
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/FieldFilterMapperPluginTests.java b/server/src/test/java/org/opensearch/index/mapper/FieldFilterMapperPluginTests.java
index 1e5a212c59825..be5fc84a2bfc7 100644
--- a/server/src/test/java/org/opensearch/index/mapper/FieldFilterMapperPluginTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/FieldFilterMapperPluginTests.java
@@ -40,8 +40,7 @@
 import org.opensearch.action.fieldcaps.FieldCapabilitiesRequest;
 import org.opensearch.action.fieldcaps.FieldCapabilitiesResponse;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.plugins.MapperPlugin;
 import org.opensearch.plugins.Plugin;
@@ -74,7 +73,7 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     public void putMappings() {
         assertAcked(client().admin().indices().prepareCreate("index1"));
         assertAcked(client().admin().indices().prepareCreate("filtered"));
-        assertAcked(client().admin().indices().preparePutMapping("index1", "filtered").setSource(TEST_ITEM, XContentType.JSON));
+        assertAcked(client().admin().indices().preparePutMapping("index1", "filtered").setSource(TEST_ITEM, MediaTypeRegistry.JSON));
     }
 
     public void testGetMappings() {
@@ -166,7 +165,7 @@ private static void assertFieldMappings(
         assertEquals("Some unexpected fields were returned: " + fields.keySet(), 0, fields.size());
     }
 
-    private void assertExpectedMappings(ImmutableOpenMap<String, MappingMetadata> mappings) {
+    private void assertExpectedMappings(Map<String, MappingMetadata> mappings) {
         assertEquals(2, mappings.size());
         assertNotFiltered(mappings.get("index1"));
         MappingMetadata filtered = mappings.get("filtered");
diff --git a/server/src/test/java/org/opensearch/index/mapper/FieldNamesFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/FieldNamesFieldMapperTests.java
index 639de9d314641..0ca1e8890ca3e 100644
--- a/server/src/test/java/org/opensearch/index/mapper/FieldNamesFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/FieldNamesFieldMapperTests.java
@@ -34,11 +34,10 @@
 
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.ArrayList;
@@ -85,9 +84,14 @@ public void testExtractFieldNames() {
     }
 
     public void testFieldType() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").startObject("_field_names").endObject().endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_field_names")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -102,7 +106,7 @@ public void testFieldType() throws Exception {
     }
 
     public void testInjectIntoDocDuringParsing() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -114,7 +118,7 @@ public void testInjectIntoDocDuringParsing() throws Exception {
                 BytesReference.bytes(
                     XContentFactory.jsonBuilder().startObject().field("a", "100").startObject("b").field("c", 42).endObject().endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -122,22 +126,21 @@ public void testInjectIntoDocDuringParsing() throws Exception {
     }
 
     public void testExplicitEnabled() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_field_names")
-                .field("enabled", true)
-                .endObject()
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "keyword")
-                .field("doc_values", false)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_field_names")
+            .field("enabled", true)
+            .endObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "keyword")
+            .field("doc_values", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -149,7 +152,7 @@ public void testExplicitEnabled() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -158,16 +161,15 @@ public void testExplicitEnabled() throws Exception {
     }
 
     public void testDisabled() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_field_names")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_field_names")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -179,7 +181,7 @@ public void testDisabled() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -188,26 +190,24 @@ public void testDisabled() throws Exception {
     }
 
     public void testMergingMappings() throws Exception {
-        String enabledMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_field_names")
-                .field("enabled", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
-        String disabledMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_field_names")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String enabledMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_field_names")
+            .field("enabled", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+        String disabledMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_field_names")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
 
         mapperService.merge("type", new CompressedXContent(enabledMapping), MapperService.MergeReason.MAPPING_UPDATE);
diff --git a/server/src/test/java/org/opensearch/index/mapper/FieldTypeLookupTests.java b/server/src/test/java/org/opensearch/index/mapper/FieldTypeLookupTests.java
index 9aa9c7d5074e7..583f9ab48edad 100644
--- a/server/src/test/java/org/opensearch/index/mapper/FieldTypeLookupTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/FieldTypeLookupTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.collect.Set;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.Set;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
diff --git a/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldDataTests.java b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldDataTests.java
new file mode 100644
index 0000000000000..e318ca5e953a3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldDataTests.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.opensearch.common.compress.CompressedXContent;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.fielddata.AbstractFieldDataTestCase;
+import org.opensearch.index.fielddata.IndexFieldData;
+
+import java.util.List;
+
+public class FlatObjectFieldDataTests extends AbstractFieldDataTestCase {
+    private String FIELD_TYPE = "flat_object";
+
+    @Override
+    protected boolean hasDocValues() {
+        return true;
+    }
+
+    public void testDocValue() throws Exception {
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("test")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", FIELD_TYPE)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+        final DocumentMapper mapper = mapperService.documentMapperParser().parse("test", new CompressedXContent(mapping));
+
+        XContentBuilder json = XContentFactory.jsonBuilder().startObject().startObject("field").field("foo", "bar").endObject().endObject();
+        ParsedDocument d = mapper.parse(new SourceToParse("test", "1", BytesReference.bytes(json), MediaTypeRegistry.JSON));
+        writer.addDocument(d.rootDoc());
+        writer.commit();
+
+        IndexFieldData<?> fieldData = getForField("field");
+        List<LeafReaderContext> readers = refreshReader();
+        assertEquals(1, readers.size());
+
+        IndexFieldData<?> valueFieldData = getForField("field._value");
+        List<LeafReaderContext> valueReaders = refreshReader();
+        assertEquals(1, valueReaders.size());
+    }
+
+    @Override
+    protected String getFieldDataType() {
+        return FIELD_TYPE;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldMapperTests.java
new file mode 100644
index 0000000000000..637072c8886c1
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldMapperTests.java
@@ -0,0 +1,146 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.index.DocValuesType;
+import org.apache.lucene.index.IndexOptions;
+import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.index.IndexableFieldType;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.query.QueryShardContext;
+
+import java.io.IOException;
+
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.hamcrest.core.StringContains.containsString;
+
+public class FlatObjectFieldMapperTests extends MapperTestCase {
+    private static final String FIELD_TYPE = "flat_object";
+    private static final String VALUE_AND_PATH_SUFFIX = "._valueAndPath";
+    private static final String VALUE_SUFFIX = "._value";
+
+    protected boolean supportsMeta() {
+        return false;
+    }
+
+    protected boolean supportsOrIgnoresBoost() {
+        return false;
+    }
+
+    public void testMapperServiceHasParser() throws IOException {
+        MapperService mapperService = createMapperService(fieldMapping(b -> { minimalMapping(b); }));
+        Mapper.TypeParser parser = mapperService.mapperRegistry.getMapperParsers().get(FIELD_TYPE);
+        assertNotNull(parser);
+        assertTrue(parser instanceof FlatObjectFieldMapper.TypeParser);
+    }
+
+    protected void assertExistsQuery(MapperService mapperService) throws IOException {
+        ParseContext.Document fields = mapperService.documentMapper().parse(source(this::writeField)).rootDoc();
+        QueryShardContext queryShardContext = createQueryShardContext(mapperService);
+        MappedFieldType fieldType = mapperService.fieldType("field");
+        Query query = fieldType.existsQuery(queryShardContext);
+        assertExistsQuery(fieldType, query, fields);
+
+    }
+
+    protected void assertExistsQuery(MappedFieldType fieldType, Query query, ParseContext.Document fields) {
+        // we always perform a term query against _field_names, even when the field
+        // is not added to _field_names because it is not indexed nor stored
+        assertThat(query, instanceOf(TermQuery.class));
+        TermQuery termQuery = (TermQuery) query;
+        assertEquals(FieldNamesFieldMapper.NAME, termQuery.getTerm().field());
+        assertEquals("field", termQuery.getTerm().text());
+        if (fieldType.isSearchable() || fieldType.isStored()) {
+            assertNotNull(fields.getField(FieldNamesFieldMapper.NAME));
+        } else {
+            assertNoFieldNamesField(fields);
+        }
+    }
+
+    public void minimalMapping(XContentBuilder b) throws IOException {
+        b.field("type", FIELD_TYPE);
+    }
+
+    /**
+     * Writes a sample value for the field to the provided {@link XContentBuilder}.
+     * @param builder builder
+     */
+    protected void writeFieldValue(XContentBuilder builder) throws IOException {
+        builder.startObject();
+        builder.field("foo", "bar");
+        builder.endObject();
+    }
+
+    public void testMinimalToMaximal() throws IOException {
+        XContentBuilder orig = JsonXContent.contentBuilder().startObject();
+        createMapperService(fieldMapping(this::minimalMapping)).documentMapper().mapping().toXContent(orig, ToXContent.EMPTY_PARAMS);
+        orig.endObject();
+        XContentBuilder parsedFromOrig = JsonXContent.contentBuilder().startObject();
+        createMapperService(orig).documentMapper().mapping().toXContent(parsedFromOrig, ToXContent.EMPTY_PARAMS);
+        parsedFromOrig.endObject();
+        assertEquals(orig.toString(), parsedFromOrig.toString());
+        assertParseMaximalWarnings();
+    }
+
+    public void testDefaults() throws Exception {
+        XContentBuilder mapping = fieldMapping(this::minimalMapping);
+        DocumentMapper mapper = createDocumentMapper(mapping);
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
+
+        String json = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("field")
+            .field("foo", "bar")
+            .endObject()
+            .endObject()
+            .toString();
+
+        ParsedDocument doc = mapper.parse(source(json));
+        IndexableField[] fields = doc.rootDoc().getFields("field");
+        assertEquals(2, fields.length);
+        assertEquals(new BytesRef("field.foo"), fields[0].binaryValue());
+
+        IndexableFieldType fieldType = fields[0].fieldType();
+        assertFalse(fieldType.tokenized());
+        assertFalse(fieldType.stored());
+        assertThat(fieldType.indexOptions(), equalTo(IndexOptions.DOCS));
+        assertEquals(DocValuesType.NONE, fieldType.docValuesType());
+
+        // Test internal substring fields as well
+        IndexableField[] fieldValues = doc.rootDoc().getFields("field" + VALUE_SUFFIX);
+        assertEquals(2, fieldValues.length);
+        assertTrue(fieldValues[0] instanceof KeywordFieldMapper.KeywordField);
+        assertEquals(new BytesRef("bar"), fieldValues[0].binaryValue());
+
+        IndexableField[] fieldValueAndPaths = doc.rootDoc().getFields("field" + VALUE_AND_PATH_SUFFIX);
+        assertEquals(2, fieldValues.length);
+        assertTrue(fieldValueAndPaths[0] instanceof KeywordFieldMapper.KeywordField);
+        assertEquals(new BytesRef("field.foo=bar"), fieldValueAndPaths[0].binaryValue());
+    }
+
+    public void testNullValue() throws IOException {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
+        MapperParsingException e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.nullField("field"))));
+        assertThat(e.getMessage(), containsString("object mapping for [_doc] tried to parse field [field] as object"));
+
+    }
+
+    @Override
+    protected void registerParameters(ParameterChecker checker) throws IOException {
+        // In the future we will want to make sure parameter updates are covered.
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldTypeTests.java
new file mode 100644
index 0000000000000..9ec053dc59d10
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/FlatObjectFieldTypeTests.java
@@ -0,0 +1,134 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.TermQuery;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.analysis.AnalyzerScope;
+import org.opensearch.index.analysis.NamedAnalyzer;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+public class FlatObjectFieldTypeTests extends FieldTypeTestCase {
+    private static MappedFieldType getFlatParentFieldType(String fieldName) {
+        Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT.id).build();
+        Mapper.BuilderContext context = new Mapper.BuilderContext(settings, new ContentPath());
+        MappedFieldType flatParentFieldType = new FlatObjectFieldMapper.Builder(fieldName).build(context).fieldType();
+        return flatParentFieldType;
+    }
+
+    public void testFetchSourceValue() throws IOException {
+        MappedFieldType mapper = getFlatParentFieldType("field");
+
+        Map<String, Object> jsonPoint = new HashMap<>();
+        jsonPoint.put("type", "flat_object");
+        jsonPoint.put("coordinates", Arrays.asList(42.0, 27.1));
+        Map<String, Object> otherJsonPoint = new HashMap<>();
+        otherJsonPoint.put("type", "Point");
+        otherJsonPoint.put("coordinates", Arrays.asList(30.0, 50.0));
+
+        ArrayList<String> jsonPointList = new ArrayList<>();
+        jsonPointList.add(jsonPoint.toString());
+
+        ArrayList<String> otherJsonPointList = new ArrayList<>();
+        otherJsonPointList.add(otherJsonPoint.toString());
+
+        assertEquals(jsonPointList, fetchSourceValue(mapper, jsonPoint, null));
+        assertEquals(otherJsonPointList, fetchSourceValue(mapper, otherJsonPoint, null));
+
+    }
+
+    public void testDirectSubfield() {
+        {
+            MappedFieldType flatParentFieldType = getFlatParentFieldType("field");
+
+            // when searching for "foo" in "field", the directSubfield is field._value field
+            String searchFieldName = ((FlatObjectFieldMapper.FlatObjectFieldType) flatParentFieldType).directSubfield();
+            assertEquals("field._value", searchFieldName);
+
+            MappedFieldType dynamicMappedFieldType = new FlatObjectFieldMapper.FlatObjectFieldType("bar", flatParentFieldType.name());
+            // when searching for "foo" in "field.bar", the directSubfield is field._valueAndPath field
+            String searchFieldNameDocPath = ((FlatObjectFieldMapper.FlatObjectFieldType) dynamicMappedFieldType).directSubfield();
+            assertEquals("field._valueAndPath", searchFieldNameDocPath);
+        }
+        {
+            NamedAnalyzer analyzer = new NamedAnalyzer("default", AnalyzerScope.INDEX, null);
+            MappedFieldType ft = new FlatObjectFieldMapper.FlatObjectFieldType("field", analyzer);
+            assertEquals("field._value", ((FlatObjectFieldMapper.FlatObjectFieldType) ft).directSubfield());
+        }
+    }
+
+    public void testRewriteValue() {
+        MappedFieldType flatParentFieldType = getFlatParentFieldType("field");
+
+        // when searching for "foo" in "field", the rewrite value is "foo"
+        String searchValues = ((FlatObjectFieldMapper.FlatObjectFieldType) flatParentFieldType).rewriteValue("foo");
+        assertEquals("foo", searchValues);
+
+        MappedFieldType dynamicMappedFieldType = new FlatObjectFieldMapper.FlatObjectFieldType("field.bar", flatParentFieldType.name());
+
+        // when searching for "foo" in "field.bar", the rewrite value is "field.bar=foo"
+        String searchFieldNameDocPath = ((FlatObjectFieldMapper.FlatObjectFieldType) dynamicMappedFieldType).directSubfield();
+        String searchValuesDocPath = ((FlatObjectFieldMapper.FlatObjectFieldType) dynamicMappedFieldType).rewriteValue("foo");
+        assertEquals("field.bar=foo", searchValuesDocPath);
+    }
+
+    public void testTermQuery() {
+
+        MappedFieldType flatParentFieldType = getFlatParentFieldType("field");
+
+        // when searching for "foo" in "field", the term query is directed to search "foo" in field._value field
+        String searchFieldName = ((FlatObjectFieldMapper.FlatObjectFieldType) flatParentFieldType).directSubfield();
+        String searchValues = ((FlatObjectFieldMapper.FlatObjectFieldType) flatParentFieldType).rewriteValue("foo");
+        assertEquals("foo", searchValues);
+        assertEquals(new TermQuery(new Term(searchFieldName, searchValues)), flatParentFieldType.termQuery(searchValues, null));
+
+        MappedFieldType dynamicMappedFieldType = new FlatObjectFieldMapper.FlatObjectFieldType("field.bar", flatParentFieldType.name());
+
+        // when searching for "foo" in "field.bar", the term query is directed to search in field._valueAndPath field
+        String searchFieldNameDocPath = ((FlatObjectFieldMapper.FlatObjectFieldType) dynamicMappedFieldType).directSubfield();
+        String searchValuesDocPath = ((FlatObjectFieldMapper.FlatObjectFieldType) dynamicMappedFieldType).rewriteValue("foo");
+        assertEquals("field.bar=foo", searchValuesDocPath);
+        assertEquals(new TermQuery(new Term(searchFieldNameDocPath, searchValuesDocPath)), dynamicMappedFieldType.termQuery("foo", null));
+
+        MappedFieldType unsearchable = new FlatObjectFieldMapper.FlatObjectFieldType("field", false, true, Collections.emptyMap());
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> unsearchable.termQuery("bar", null));
+        assertEquals("Cannot search on field [field] since it is not indexed.", e.getMessage());
+    }
+
+    public void testExistsQuery() {
+        {
+            MappedFieldType ft = getFlatParentFieldType("field");
+            // when checking on the flat_object field name "field", check if exist in the field mapper names
+            assertEquals(new TermQuery(new Term(FieldNamesFieldMapper.NAME, "field")), ft.existsQuery(null));
+
+            // when checking if a subfield within the flat_object, for example, "field.bar", use term query in the flat_object field
+            MappedFieldType dynamicMappedFieldType = new FlatObjectFieldMapper.FlatObjectFieldType("field.bar", ft.name());
+            assertEquals(new TermQuery(new Term("field", "field.bar")), dynamicMappedFieldType.existsQuery(null));
+
+        }
+        {
+            FlatObjectFieldMapper.FlatObjectFieldType ft = new FlatObjectFieldMapper.FlatObjectFieldType(
+                "field",
+                true,
+                false,
+                Collections.emptyMap()
+            );
+            assertEquals(new TermQuery(new Term(FieldNamesFieldMapper.NAME, "field")), ft.existsQuery(null));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/GenericStoreDynamicTemplateTests.java b/server/src/test/java/org/opensearch/index/mapper/GenericStoreDynamicTemplateTests.java
index 9c9c0440231de..6d816c6aab69c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/GenericStoreDynamicTemplateTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/GenericStoreDynamicTemplateTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -47,17 +47,17 @@ public class GenericStoreDynamicTemplateTests extends OpenSearchSingleNodeTestCa
     public void testSimple() throws Exception {
         String mapping = copyToStringFromClasspath("/org/opensearch/index/mapper/dynamictemplate/genericstore/test-mapping.json");
         IndexService index = createIndex("test");
-        client().admin().indices().preparePutMapping("test").setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping("test").setSource(mapping, MediaTypeRegistry.JSON).get();
 
         MapperService mapperService = index.mapperService();
 
         byte[] json = copyToBytesFromClasspath("/org/opensearch/index/mapper/dynamictemplate/genericstore/test-data.json");
         ParsedDocument parsedDoc = mapperService.documentMapper()
-            .parse(new SourceToParse("test", "1", new BytesArray(json), XContentType.JSON));
+            .parse(new SourceToParse("test", "1", new BytesArray(json), MediaTypeRegistry.JSON));
         client().admin()
             .indices()
             .preparePutMapping("test")
-            .setSource(parsedDoc.dynamicMappingsUpdate().toString(), XContentType.JSON)
+            .setSource(parsedDoc.dynamicMappingsUpdate().toString(), MediaTypeRegistry.JSON)
             .get();
         Document doc = parsedDoc.rootDoc();
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/GeoPointFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/GeoPointFieldMapperTests.java
index 6a6e6b190bff3..cbb5fc8ce5a22 100644
--- a/server/src/test/java/org/opensearch/index/mapper/GeoPointFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/GeoPointFieldMapperTests.java
@@ -34,8 +34,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.hamcrest.CoreMatchers;
 
 import java.io.IOException;
@@ -56,7 +56,7 @@ public class GeoPointFieldMapperTests extends FieldMapperTestCase2<GeoPointField
 
     @Override
     protected Set<String> unsupportedProperties() {
-        return org.opensearch.common.collect.Set.of("analyzer", "similarity", "doc_values");
+        return Set.of("analyzer", "similarity", "doc_values");
     }
 
     @Override
@@ -352,6 +352,59 @@ public void testInvalidGeopointValuesIgnored() throws Exception {
         );
     }
 
+    public void testGeoJsonSingleValue() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
+        ParsedDocument doc = mapper.parse(
+            source(b -> b.startObject("field").field("type", "Point").array("coordinates", new double[] { 1.1, 1.2 }).endObject())
+        );
+        assertThat(doc.rootDoc().getField("field"), notNullValue());
+    }
+
+    public void testGeoJsonArray() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
+        ParsedDocument doc = mapper.parse(
+            source(
+                b -> b.startArray("field")
+                    .startObject()
+                    .field("type", "Point")
+                    .array("coordinates", new double[] { 1.1, 1.2 })
+                    .endObject()
+                    .startObject()
+                    .field("type", "Point")
+                    .array("coordinates", new double[] { 1.3, 1.4 })
+                    .endObject()
+                    .endArray()
+            )
+        );
+        assertThat(doc.rootDoc().getField("field"), notNullValue());
+        assertThat(doc.rootDoc().getFields("field"), arrayWithSize(4));
+    }
+
+    public void testGeoJsonIgnoreZValue() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "geo_point").field("ignore_z_value", true)));
+        ParsedDocument doc = mapper.parse(
+            source(b -> b.startObject("field").field("type", "Point").array("coordinates", new double[] { 1.1, 1.2, 1.3 }).endObject())
+        );
+        assertThat(doc.rootDoc().getField("field"), notNullValue());
+    }
+
+    public void testGeoJsonZValueException() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "geo_point").field("ignore_z_value", false)));
+        Exception e = expectThrows(
+            MapperParsingException.class,
+            () -> mapper.parse(
+                source(b -> b.startObject("field").field("type", "Point").array("coordinates", new double[] { 1.1, 1.2, 1.3 }).endObject())
+            )
+        );
+        assertThat(e.getCause().getMessage(), containsString("but [ignore_z_value] parameter is [false]"));
+    }
+
+    public void testGeoJsonIgnoreInvalidForm() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "geo_point").field("ignore_malformed", "true")));
+        ParsedDocument doc = mapper.parse(source(b -> b.startObject("field").array("coordinates", new double[] { 1.1, 1.2 }).endObject()));
+        assertThat(doc.rootDoc().getField("field"), nullValue());
+    }
+
     @Override
     protected GeoPointFieldMapper.Builder newBuilder() {
         return new GeoPointFieldMapper.Builder("geo");
diff --git a/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldMapperTests.java
index 187f17cbfd6ff..016862e3ffabc 100644
--- a/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldMapperTests.java
@@ -32,11 +32,11 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.common.Explicit;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.List;
 import org.opensearch.common.geo.builders.ShapeBuilder;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
 import org.junit.Before;
@@ -44,6 +44,7 @@
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.Set;
 
 import static org.hamcrest.Matchers.containsString;
@@ -55,7 +56,7 @@ public class GeoShapeFieldMapperTests extends FieldMapperTestCase2<GeoShapeField
 
     @Override
     protected Set<String> unsupportedProperties() {
-        return org.opensearch.common.collect.Set.of("analyzer", "similarity", "doc_values", "store");
+        return Set.of("analyzer", "similarity", "store");
     }
 
     @Override
@@ -117,7 +118,7 @@ public void testDefaultConfiguration() throws IOException {
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
         assertThat(geoShapeFieldMapper.fieldType().orientation(), equalTo(GeoShapeFieldMapper.Defaults.ORIENTATION.value()));
-        assertThat(geoShapeFieldMapper.fieldType().hasDocValues(), equalTo(false));
+        assertThat(geoShapeFieldMapper.fieldType().hasDocValues(), equalTo(true));
     }
 
     /**
@@ -228,6 +229,7 @@ public void testSerializeDefaults() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
         assertThat(
             Strings.toString(
+                MediaTypeRegistry.JSON,
                 mapper.mappers().getMapper("field"),
                 new ToXContent.MapParams(Collections.singletonMap("include_defaults", "true"))
             ),
@@ -246,7 +248,7 @@ public void testGeoShapeArrayParsing() throws Exception {
             b.endArray();
         }));
         assertThat(document.docs(), hasSize(1));
-        assertThat(document.docs().get(0).getFields("field").length, equalTo(2));
+        assertThat(document.docs().get(0).getFields("field").length, equalTo(4));
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldTypeTests.java
index f4767403ffbf7..127117ee9c7b2 100644
--- a/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/GeoShapeFieldTypeTests.java
@@ -49,13 +49,13 @@ public void testFetchSourceValue() throws IOException {
 
         MappedFieldType mapper = new GeoShapeFieldMapper.Builder("field").build(context).fieldType();
 
-        Map<String, Object> jsonLineString = org.opensearch.common.collect.Map.of(
+        Map<String, Object> jsonLineString = Map.of(
             "type",
             "LineString",
             "coordinates",
             Arrays.asList(Arrays.asList(42.0, 27.1), Arrays.asList(30.0, 50.0))
         );
-        Map<String, Object> jsonPoint = org.opensearch.common.collect.Map.of("type", "Point", "coordinates", Arrays.asList(14.0, 15.0));
+        Map<String, Object> jsonPoint = Map.of("type", "Point", "coordinates", Arrays.asList(14.0, 15.0));
         String wktLineString = "LINESTRING (42.0 27.1, 30.0 50.0)";
         String wktPoint = "POINT (14.0 15.0)";
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/IdFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/IdFieldMapperTests.java
index e897abad405d5..e6ef5a9069af6 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IdFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IdFieldMapperTests.java
@@ -34,19 +34,18 @@
 
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -63,7 +62,7 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testIncludeInObjectNotAllowed() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -74,7 +73,7 @@ public void testIncludeInObjectNotAllowed() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("_id", "1").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
             fail("Expected failure to parse metadata field");
@@ -90,7 +89,7 @@ public void testDefaults() throws IOException {
         Settings indexSettings = Settings.EMPTY;
         MapperService mapperService = createIndex("test", indexSettings).mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent("{\"type\":{}}"), MergeReason.MAPPING_UPDATE);
-        ParsedDocument document = mapper.parse(new SourceToParse("index", "id", new BytesArray("{}"), XContentType.JSON));
+        ParsedDocument document = mapper.parse(new SourceToParse("index", "id", new BytesArray("{}"), MediaTypeRegistry.JSON));
         IndexableField[] fields = document.rootDoc().getFields(IdFieldMapper.NAME);
         assertEquals(1, fields.length);
         assertEquals(IndexOptions.DOCS, fields[0].fieldType().indexOptions());
@@ -114,10 +113,9 @@ public void testEnableFieldData() throws IOException {
             .setTransientSettings(Settings.builder().put(IndicesService.INDICES_ID_FIELD_DATA_ENABLED_SETTING.getKey(), false))
             .get();
         try {
-            IllegalArgumentException exc = expectThrows(
-                IllegalArgumentException.class,
-                () -> ft.fielddataBuilder("test", () -> { throw new UnsupportedOperationException(); }).build(null, null)
-            );
+            IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> ft.fielddataBuilder("test", () -> {
+                throw new UnsupportedOperationException();
+            }).build(null, null));
             assertThat(exc.getMessage(), containsString(IndicesService.INDICES_ID_FIELD_DATA_ENABLED_SETTING.getKey()));
             assertFalse(ft.isAggregatable());
         } finally {
diff --git a/server/src/test/java/org/opensearch/index/mapper/IdFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/IdFieldTypeTests.java
index 8a37a72ab7be4..3fb6be2203cd1 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IdFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IdFieldTypeTests.java
@@ -40,6 +40,7 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.test.OpenSearchTestCase;
+
 import org.mockito.Mockito;
 
 public class IdFieldTypeTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/index/mapper/IgnoredFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/IgnoredFieldTypeTests.java
index 4749c3280c89e..ef1530557d587 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IgnoredFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IgnoredFieldTypeTests.java
@@ -33,11 +33,14 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.RegexpQuery;
 import org.apache.lucene.search.WildcardQuery;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.automaton.Operations;
+import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.OpenSearchException;
 
 public class IgnoredFieldTypeTests extends FieldTypeTestCase {
@@ -45,7 +48,7 @@ public class IgnoredFieldTypeTests extends FieldTypeTestCase {
     public void testPrefixQuery() {
         MappedFieldType ft = IgnoredFieldMapper.IgnoredFieldType.INSTANCE;
 
-        Query expected = new PrefixQuery(new Term("_ignored", new BytesRef("foo*")));
+        Query expected = new PrefixQuery(new Term("_ignored", new BytesRef("foo*")), MultiTermQuery.CONSTANT_SCORE_REWRITE);
         assertEquals(expected, ft.prefixQuery("foo*", null, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(OpenSearchException.class, () -> ft.prefixQuery("foo*", null, MOCK_QSC_DISALLOW_EXPENSIVE));
@@ -59,7 +62,14 @@ public void testPrefixQuery() {
     public void testRegexpQuery() {
         MappedFieldType ft = IgnoredFieldMapper.IgnoredFieldType.INSTANCE;
 
-        Query expected = new RegexpQuery(new Term("_ignored", new BytesRef("foo?")));
+        Query expected = new RegexpQuery(
+            new Term("_ignored", new BytesRef("foo?")),
+            RegExp.ALL,
+            0,
+            RegexpQuery.DEFAULT_PROVIDER,
+            Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+            MultiTermQuery.CONSTANT_SCORE_REWRITE
+        );
         assertEquals(expected, ft.regexpQuery("foo?", 0, 0, 10, null, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(
@@ -73,7 +83,7 @@ public void testWildcardQuery() {
         MappedFieldType ft = IgnoredFieldMapper.IgnoredFieldType.INSTANCE;
 
         Query expected = new WildcardQuery(new Term("_ignored", new BytesRef("foo*")));
-        assertEquals(expected, ft.wildcardQuery("foo*", null, MOCK_QSC));
+        assertEquals(expected, ft.wildcardQuery("foo*", MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(
             OpenSearchException.class,
diff --git a/server/src/test/java/org/opensearch/index/mapper/IndexFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/IndexFieldMapperTests.java
index c4225cb576550..b194e08d17813 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IndexFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IndexFieldMapperTests.java
@@ -32,21 +32,20 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
-
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.nullValue;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.util.Collection;
 
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+
 public class IndexFieldMapperTests extends OpenSearchSingleNodeTestCase {
 
     @Override
@@ -55,7 +54,7 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testDefaultDisabledIndexMapper() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -65,7 +64,7 @@ public void testDefaultDisabledIndexMapper() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -74,9 +73,14 @@ public void testDefaultDisabledIndexMapper() throws Exception {
     }
 
     public void testIndexNotConfigurable() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").startObject("_index").endObject().endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_index")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         MapperParsingException e = expectThrows(MapperParsingException.class, () -> parser.parse("type", new CompressedXContent(mapping)));
         assertEquals("_index is not configurable", e.getMessage());
diff --git a/server/src/test/java/org/opensearch/index/mapper/IpFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/IpFieldMapperTests.java
index bd1cd7eb40b99..0f30e93f0622a 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IpFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IpFieldMapperTests.java
@@ -40,7 +40,7 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.termvectors.TermVectorsService;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldMapperTests.java
index ce444f76eac17..8de78a99c5e8a 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldMapperTests.java
@@ -34,14 +34,13 @@
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.termvectors.TermVectorsService;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -73,8 +72,8 @@ public void testStoreCidr() throws Exception {
             .field("type", "ip_range")
             .field("store", true);
         mapping = mapping.endObject().endObject().endObject().endObject();
-        DocumentMapper mapper = parser.parse("type", new CompressedXContent(Strings.toString(mapping)));
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping.toString()));
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
         final Map<String, String> cases = new HashMap<>();
         cases.put("192.168.0.0/15", "192.169.255.255");
         cases.put("192.168.0.0/16", "192.168.255.255");
@@ -119,18 +118,17 @@ public void testIgnoreMalformed() throws Exception {
         final DocumentMapper mapper = parser.parse(
             "type",
             new CompressedXContent(
-                Strings.toString(
-                    XContentFactory.jsonBuilder()
-                        .startObject()
-                        .startObject("type")
-                        .startObject("properties")
-                        .startObject("field")
-                        .field("type", "ip_range")
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                )
+                XContentFactory.jsonBuilder()
+                    .startObject()
+                    .startObject("type")
+                    .startObject("properties")
+                    .startObject("field")
+                    .field("type", "ip_range")
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .toString()
             )
         );
 
@@ -141,19 +139,18 @@ public void testIgnoreMalformed() throws Exception {
         final DocumentMapper mapper2 = parser.parse(
             "type",
             new CompressedXContent(
-                Strings.toString(
-                    XContentFactory.jsonBuilder()
-                        .startObject()
-                        .startObject("type")
-                        .startObject("properties")
-                        .startObject("field")
-                        .field("type", "ip_range")
-                        .field("ignore_malformed", true)
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                )
+                XContentFactory.jsonBuilder()
+                    .startObject()
+                    .startObject("type")
+                    .startObject("properties")
+                    .startObject("field")
+                    .field("type", "ip_range")
+                    .field("ignore_malformed", true)
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .toString()
             )
         );
 
@@ -176,6 +173,6 @@ private final SourceToParse source(CheckedConsumer<XContentBuilder, IOException>
         XContentBuilder builder = JsonXContent.contentBuilder().startObject();
         build.accept(builder);
         builder.endObject();
-        return new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON);
+        return new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON);
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldTypeTests.java
index c2c6293eec4bd..36edc4e92504b 100644
--- a/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/IpRangeFieldTypeTests.java
@@ -47,11 +47,8 @@ public void testFetchSourceValue() throws IOException {
         Mapper.BuilderContext context = new Mapper.BuilderContext(settings, new ContentPath());
 
         RangeFieldMapper mapper = new RangeFieldMapper.Builder("field", RangeType.IP, true, Version.V_EMPTY).build(context);
-        Map<String, Object> range = org.opensearch.common.collect.Map.of("gte", "2001:db8:0:0:0:0:2:1");
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("gte", "2001:db8::2:1")),
-            fetchSourceValue(mapper.fieldType(), range)
-        );
+        Map<String, Object> range = Map.of("gte", "2001:db8:0:0:0:0:2:1");
+        assertEquals(Collections.singletonList(Map.of("gte", "2001:db8::2:1")), fetchSourceValue(mapper.fieldType(), range));
         assertEquals(Collections.singletonList("2001:db8::2:1/32"), fetchSourceValue(mapper.fieldType(), "2001:db8:0:0:0:0:2:1/32"));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/JavaMultiFieldMergeTests.java b/server/src/test/java/org/opensearch/index/mapper/JavaMultiFieldMergeTests.java
index 7e00a463124f1..93a6b0a59b864 100644
--- a/server/src/test/java/org/opensearch/index/mapper/JavaMultiFieldMergeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/JavaMultiFieldMergeTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
@@ -56,7 +56,7 @@ public void testMergeMultiField() throws Exception {
         assertThat(mapperService.fieldType("name.indexed"), nullValue());
 
         BytesReference json = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("name", "some name").endObject());
-        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         IndexableField f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
@@ -72,7 +72,7 @@ public void testMergeMultiField() throws Exception {
         assertThat(mapperService.fieldType("name.not_indexed2"), nullValue());
         assertThat(mapperService.fieldType("name.not_indexed3"), nullValue());
 
-        doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
@@ -109,7 +109,7 @@ public void testUpgradeFromMultiFieldTypeToMultiFields() throws Exception {
         assertThat(mapperService.fieldType("name.indexed"), nullValue());
 
         BytesReference json = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("name", "some name").endObject());
-        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         IndexableField f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
@@ -125,7 +125,7 @@ public void testUpgradeFromMultiFieldTypeToMultiFields() throws Exception {
         assertThat(mapperService.fieldType("name.not_indexed2"), nullValue());
         assertThat(mapperService.fieldType("name.not_indexed3"), nullValue());
 
-        doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
         f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
diff --git a/server/src/test/java/org/opensearch/index/mapper/KeywordFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/KeywordFieldMapperTests.java
index 7059e908c078f..4da21da40e0d8 100644
--- a/server/src/test/java/org/opensearch/index/mapper/KeywordFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/KeywordFieldMapperTests.java
@@ -33,8 +33,6 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockLowerCaseFilter;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.core.LowerCaseFilter;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
@@ -43,9 +41,10 @@
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.IndexableFieldType;
+import org.apache.lucene.tests.analysis.MockLowerCaseFilter;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.CharFilterFactory;
@@ -69,10 +68,10 @@
 
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
-import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 
 public class KeywordFieldMapperTests extends MapperTestCase {
 
@@ -134,7 +133,7 @@ protected Collection<? extends Plugin> getPlugins() {
     protected IndexAnalyzers createIndexAnalyzers(IndexSettings indexSettings) {
         return new IndexAnalyzers(
             singletonMap("default", new NamedAnalyzer("default", AnalyzerScope.INDEX, new StandardAnalyzer())),
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 "lowercase",
                 new NamedAnalyzer("lowercase", AnalyzerScope.INDEX, new LowercaseNormalizer()),
                 "other_lowercase",
@@ -173,7 +172,7 @@ protected void minimalMapping(XContentBuilder b) throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     protected void registerParameters(ParameterChecker checker) throws IOException {
@@ -208,7 +207,7 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
     public void testDefaults() throws Exception {
         XContentBuilder mapping = fieldMapping(this::minimalMapping);
         DocumentMapper mapper = createDocumentMapper(mapping);
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
         IndexableField[] fields = doc.rootDoc().getFields("field");
@@ -309,7 +308,7 @@ public void testIndexOptions() throws IOException {
     public void testBoost() throws IOException {
         MapperService mapperService = createMapperService(fieldMapping(b -> b.field("type", "keyword").field("boost", 2f)));
         assertThat(mapperService.fieldType("field").boost(), equalTo(2f));
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     public void testEnableNorms() throws IOException {
diff --git a/server/src/test/java/org/opensearch/index/mapper/KeywordFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/KeywordFieldTypeTests.java
index 6b7216a584ca9..0d8ef6784a28c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/KeywordFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/KeywordFieldTypeTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.index.mapper;
 
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.LowerCaseFilter;
 import org.apache.lucene.analysis.TokenFilter;
@@ -43,6 +44,7 @@
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.FuzzyQuery;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.NormsFieldExistsQuery;
 import org.apache.lucene.search.RegexpQuery;
 import org.apache.lucene.search.TermInSetQuery;
@@ -72,6 +74,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 public class KeywordFieldTypeTests extends FieldTypeTestCase {
 
@@ -171,7 +174,10 @@ public void testRangeQuery() {
 
     public void testRegexpQuery() {
         MappedFieldType ft = new KeywordFieldType("field");
-        assertEquals(new RegexpQuery(new Term("field", "foo.*")), ft.regexpQuery("foo.*", 0, 0, 10, null, MOCK_QSC));
+        assertEquals(
+            new RegexpQuery(new Term("field", "foo.*")),
+            ft.regexpQuery("foo.*", 0, 0, 10, MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC)
+        );
 
         MappedFieldType unsearchable = new KeywordFieldType("field", false, true, Collections.emptyMap());
         IllegalArgumentException e = expectThrows(
@@ -245,18 +251,12 @@ public void testFetchSourceValue() throws IOException {
 
     private static IndexAnalyzers createIndexAnalyzers() {
         return new IndexAnalyzers(
-            org.opensearch.common.collect.Map.of("default", new NamedAnalyzer("default", AnalyzerScope.INDEX, new StandardAnalyzer())),
-            org.opensearch.common.collect.Map.ofEntries(
-                org.opensearch.common.collect.Map.entry(
-                    "lowercase",
-                    new NamedAnalyzer("lowercase", AnalyzerScope.INDEX, new LowercaseNormalizer())
-                ),
-                org.opensearch.common.collect.Map.entry(
-                    "other_lowercase",
-                    new NamedAnalyzer("other_lowercase", AnalyzerScope.INDEX, new LowercaseNormalizer())
-                )
+            Map.of("default", new NamedAnalyzer("default", AnalyzerScope.INDEX, new StandardAnalyzer())),
+            Map.ofEntries(
+                Map.entry("lowercase", new NamedAnalyzer("lowercase", AnalyzerScope.INDEX, new LowercaseNormalizer())),
+                Map.entry("other_lowercase", new NamedAnalyzer("other_lowercase", AnalyzerScope.INDEX, new LowercaseNormalizer()))
             ),
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 "lowercase",
                 new NamedAnalyzer(
                     "lowercase",
diff --git a/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapperTests.java
index 30f9f283d9208..048b51d39ca6c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldMapperTests.java
@@ -38,14 +38,14 @@
 import org.apache.lucene.spatial.prefix.tree.QuadPrefixTree;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Explicit;
-import org.opensearch.common.Strings;
-import org.opensearch.common.collect.List;
 import org.opensearch.common.geo.GeoUtils;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.SpatialStrategy;
 import org.opensearch.common.geo.builders.ShapeBuilder;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Point;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.plugins.Plugin;
@@ -53,6 +53,7 @@
 
 import java.io.IOException;
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
 
 import static java.util.Collections.singletonMap;
@@ -79,7 +80,7 @@ protected LegacyGeoShapeFieldMapper.Builder newBuilder() {
 
     @Override
     protected Set<String> unsupportedProperties() {
-        return org.opensearch.common.collect.Set.of("analyzer", "similarity", "doc_values", "store");
+        return Set.of("analyzer", "similarity", "doc_values", "store");
     }
 
     @Override
@@ -138,7 +139,7 @@ public void testDefaultConfiguration() throws IOException {
         DocumentMapper mapper = createDocumentMapper(mapping);
         Mapper fieldMapper = mapper.mappers().getMapper("field");
         assertThat(fieldMapper, instanceOf(LegacyGeoShapeFieldMapper.class));
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
 
         LegacyGeoShapeFieldMapper geoShapeFieldMapper = (LegacyGeoShapeFieldMapper) fieldMapper;
         assertThat(geoShapeFieldMapper.fieldType().tree(), equalTo(LegacyGeoShapeFieldMapper.DeprecatedParameters.Defaults.TREE));
@@ -538,13 +539,13 @@ public void testSerializeDefaults() throws Exception {
         ToXContent.Params includeDefaults = new ToXContent.MapParams(singletonMap("include_defaults", "true"));
         {
             DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "geo_shape").field("tree", "quadtree")));
-            String serialized = Strings.toString(mapper.mappers().getMapper("field"), includeDefaults);
+            String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper.mappers().getMapper("field"), includeDefaults);
             assertTrue(serialized, serialized.contains("\"precision\":\"50.0m\""));
             assertTrue(serialized, serialized.contains("\"tree_levels\":21"));
         }
         {
             DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "geo_shape").field("tree", "geohash")));
-            String serialized = Strings.toString(mapper.mappers().getMapper("field"), includeDefaults);
+            String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper.mappers().getMapper("field"), includeDefaults);
             assertTrue(serialized, serialized.contains("\"precision\":\"50.0m\""));
             assertTrue(serialized, serialized.contains("\"tree_levels\":9"));
         }
@@ -552,7 +553,7 @@ public void testSerializeDefaults() throws Exception {
             DocumentMapper mapper = createDocumentMapper(
                 fieldMapping(b -> b.field("type", "geo_shape").field("tree", "quadtree").field("tree_levels", "6"))
             );
-            String serialized = Strings.toString(mapper.mappers().getMapper("field"), includeDefaults);
+            String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper.mappers().getMapper("field"), includeDefaults);
             assertFalse(serialized, serialized.contains("\"precision\":"));
             assertTrue(serialized, serialized.contains("\"tree_levels\":6"));
         }
@@ -560,7 +561,7 @@ public void testSerializeDefaults() throws Exception {
             DocumentMapper mapper = createDocumentMapper(
                 fieldMapping(b -> b.field("type", "geo_shape").field("tree", "quadtree").field("precision", "6"))
             );
-            String serialized = Strings.toString(mapper.mappers().getMapper("field"), includeDefaults);
+            String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper.mappers().getMapper("field"), includeDefaults);
             assertTrue(serialized, serialized.contains("\"precision\":\"6.0m\""));
             assertFalse(serialized, serialized.contains("\"tree_levels\":"));
         }
@@ -568,7 +569,7 @@ public void testSerializeDefaults() throws Exception {
             DocumentMapper mapper = createDocumentMapper(
                 fieldMapping(b -> b.field("type", "geo_shape").field("tree", "quadtree").field("precision", "6m").field("tree_levels", "5"))
             );
-            String serialized = Strings.toString(mapper.mappers().getMapper("field"), includeDefaults);
+            String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper.mappers().getMapper("field"), includeDefaults);
             assertTrue(serialized, serialized.contains("\"precision\":\"6.0m\""));
             assertTrue(serialized, serialized.contains("\"tree_levels\":5"));
         }
@@ -590,7 +591,7 @@ public void testPointsOnlyDefaultsWithTermStrategy() throws IOException {
         assertThat(strategy.getGrid().getMaxLevels(), equalTo(23));
         assertThat(strategy.isPointsOnly(), equalTo(true));
         // term strategy changes the default for points_only, check that we handle it correctly
-        assertThat(Strings.toString(geoShapeFieldMapper), not(containsString("points_only")));
+        assertThat(Strings.toString(MediaTypeRegistry.JSON, geoShapeFieldMapper), not(containsString("points_only")));
         assertFieldWarnings("tree", "precision", "strategy");
     }
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldTypeTests.java
index 5157232bea1a2..45161bed1d40e 100644
--- a/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/LegacyGeoShapeFieldTypeTests.java
@@ -63,13 +63,13 @@ public void testFetchSourceValue() throws IOException {
 
         MappedFieldType mapper = new LegacyGeoShapeFieldMapper.Builder("field").build(context).fieldType();
 
-        Map<String, Object> jsonLineString = org.opensearch.common.collect.Map.of(
+        Map<String, Object> jsonLineString = Map.of(
             "type",
             "LineString",
             "coordinates",
             Arrays.asList(Arrays.asList(42.0, 27.1), Arrays.asList(30.0, 50.0))
         );
-        Map<String, Object> jsonPoint = org.opensearch.common.collect.Map.of("type", "Point", "coordinates", Arrays.asList(14.0, 15.0));
+        Map<String, Object> jsonPoint = Map.of("type", "Point", "coordinates", Arrays.asList(14.0, 15.0));
         String wktLineString = "LINESTRING (42.0 27.1, 30.0 50.0)";
         String wktPoint = "POINT (14.0 15.0)";
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/MapperServiceTests.java b/server/src/test/java/org/opensearch/index/mapper/MapperServiceTests.java
index b58c0bf69c298..f0f34dff0a38f 100644
--- a/server/src/test/java/org/opensearch/index/mapper/MapperServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/MapperServiceTests.java
@@ -34,12 +34,11 @@
 
 import org.apache.lucene.analysis.TokenStream;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
@@ -56,8 +55,8 @@
 import org.opensearch.indices.analysis.AnalysisModule.AnalysisProvider;
 import org.opensearch.plugins.AnalysisPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -267,22 +266,21 @@ public void testFieldAliasWithMismatchedNestedScope() throws Throwable {
     }
 
     public void testTotalFieldsLimitWithFieldAlias() throws Throwable {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("alias")
-                .field("type", "alias")
-                .field("path", "field")
-                .endObject()
-                .startObject("field")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("alias")
+            .field("type", "alias")
+            .field("path", "field")
+            .endObject()
+            .startObject("field")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         int numberOfFieldsIncludingAlias = 2;
         createIndex(
@@ -340,10 +338,9 @@ public void testFieldNameLengthLimit() throws Throwable {
             )
         );
 
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { mapperService.merge("type", mappingUpdate, updateOrPreflight()); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            mapperService.merge("type", mappingUpdate, updateOrPreflight());
+        });
 
         assertEquals("Field name [" + testString + "] is longer than the limit of [" + maxFieldNameLength + "] characters", e.getMessage());
     }
@@ -371,10 +368,9 @@ public void testObjectNameLengthLimit() throws Throwable {
             )
         );
 
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { mapperService.merge("type", mapping, updateOrPreflight()); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            mapperService.merge("type", mapping, updateOrPreflight());
+        });
 
         assertEquals("Field name [" + testString + "] is longer than the limit of [" + maxFieldNameLength + "] characters", e.getMessage());
     }
@@ -406,10 +402,9 @@ public void testAliasFieldNameLengthLimit() throws Throwable {
             )
         );
 
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { mapperService.merge("type", mapping, updateOrPreflight()); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            mapperService.merge("type", mapping, updateOrPreflight());
+        });
 
         assertEquals("Field name [" + testString + "] is longer than the limit of [" + maxFieldNameLength + "] characters", e.getMessage());
     }
diff --git a/server/src/test/java/org/opensearch/index/mapper/MockMetadataMapperPlugin.java b/server/src/test/java/org/opensearch/index/mapper/MockMetadataMapperPlugin.java
index 087b0138732f9..aafff8de3f9cf 100644
--- a/server/src/test/java/org/opensearch/index/mapper/MockMetadataMapperPlugin.java
+++ b/server/src/test/java/org/opensearch/index/mapper/MockMetadataMapperPlugin.java
@@ -34,7 +34,7 @@
 
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.StringField;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.plugins.MapperPlugin;
 import org.opensearch.plugins.Plugin;
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/MultiFieldTests.java b/server/src/test/java/org/opensearch/index/mapper/MultiFieldTests.java
index 4027cf20baba8..92ff57aa72e51 100644
--- a/server/src/test/java/org/opensearch/index/mapper/MultiFieldTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/MultiFieldTests.java
@@ -35,14 +35,13 @@
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.support.XContentMapValues;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.index.mapper.TextFieldMapper.TextFieldType;
@@ -76,7 +75,7 @@ private void testMultiField(String mapping) throws Exception {
             .merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/opensearch/index/mapper/multifield/test-data.json"));
-        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
 
         IndexableField f = doc.getField("name");
         assertThat(f.name(), equalTo("name"));
@@ -155,7 +154,7 @@ public void testBuildThenParse() throws Exception {
             .parse(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(builtMapping));
 
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/opensearch/index/mapper/multifield/test-data.json"));
-        Document doc = docMapper.parse(new SourceToParse("test", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = docMapper.parse(new SourceToParse("test", "1", json, MediaTypeRegistry.JSON)).rootDoc();
 
         IndexableField f = doc.getField("name");
         assertThat(f.name(), equalTo("name"));
@@ -196,7 +195,7 @@ public void testMultiFieldsInConsistentOrder() throws Exception {
             builder = builder.startObject(multiFieldName).field("type", "text").endObject();
         }
         builder = builder.endObject().endObject().endObject().endObject().endObject();
-        String mapping = Strings.toString(builder);
+        String mapping = builder.toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -222,22 +221,21 @@ public void testMultiFieldsInConsistentOrder() throws Exception {
     }
 
     public void testObjectFieldNotAllowed() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("my_field")
-                .field("type", "text")
-                .startObject("fields")
-                .startObject("multi")
-                .field("type", "object")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("my_field")
+            .field("type", "text")
+            .startObject("fields")
+            .startObject("multi")
+            .field("type", "object")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         final DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         try {
             parser.parse("type", new CompressedXContent(mapping));
@@ -248,22 +246,21 @@ public void testObjectFieldNotAllowed() throws Exception {
     }
 
     public void testNestedFieldNotAllowed() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("my_field")
-                .field("type", "text")
-                .startObject("fields")
-                .startObject("multi")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("my_field")
+            .field("type", "text")
+            .startObject("fields")
+            .startObject("multi")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         final DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         try {
             parser.parse("type", new CompressedXContent(mapping));
@@ -293,7 +290,7 @@ public void testMultiFieldWithDot() throws IOException {
 
         MapperService mapperService = createIndex("test").mapperService();
         try {
-            mapperService.documentMapperParser().parse("my_type", new CompressedXContent(Strings.toString(mapping)));
+            mapperService.documentMapperParser().parse("my_type", new CompressedXContent(mapping.toString()));
             fail("this should throw an exception because one field contains a dot");
         } catch (MapperParsingException e) {
             assertThat(e.getMessage(), equalTo("Field name [raw.foo] which is a multi field of [city] cannot contain '.'"));
diff --git a/server/src/test/java/org/opensearch/index/mapper/NestedObjectMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/NestedObjectMapperTests.java
index fe3ce5da6c90a..f3f682697a930 100644
--- a/server/src/test/java/org/opensearch/index/mapper/NestedObjectMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/NestedObjectMapperTests.java
@@ -33,18 +33,17 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.index.mapper.ObjectMapper.Dynamic;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -66,18 +65,17 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testEmptyNested() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -88,7 +86,7 @@ public void testEmptyNested() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").nullField("nested1").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -101,7 +99,7 @@ public void testEmptyNested() throws Exception {
                 BytesReference.bytes(
                     XContentFactory.jsonBuilder().startObject().field("field", "value").startArray("nested").endArray().endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -109,18 +107,17 @@ public void testEmptyNested() throws Exception {
     }
 
     public void testSingleNested() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -144,12 +141,12 @@ public void testSingleNested() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
         assertThat(doc.docs().size(), equalTo(2));
-        assertThat(doc.docs().get(0).get(TypeFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePathAsString()));
+        assertThat(doc.docs().get(0).get(NestedPathFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePath()));
         assertThat(doc.docs().get(0).get("nested1.field1"), equalTo("1"));
         assertThat(doc.docs().get(0).get("nested1.field2"), equalTo("2"));
 
@@ -175,15 +172,15 @@ public void testSingleNested() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
         assertThat(doc.docs().size(), equalTo(3));
-        assertThat(doc.docs().get(0).get(TypeFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePathAsString()));
+        assertThat(doc.docs().get(0).get(NestedPathFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePath()));
         assertThat(doc.docs().get(0).get("nested1.field1"), equalTo("1"));
         assertThat(doc.docs().get(0).get("nested1.field2"), equalTo("2"));
-        assertThat(doc.docs().get(1).get(TypeFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePathAsString()));
+        assertThat(doc.docs().get(1).get(NestedPathFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePath()));
         assertThat(doc.docs().get(1).get("nested1.field1"), equalTo("3"));
         assertThat(doc.docs().get(1).get("nested1.field2"), equalTo("4"));
 
@@ -191,23 +188,22 @@ public void testSingleNested() throws Exception {
     }
 
     public void testMultiNested() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -257,7 +253,7 @@ public void testMultiNested() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -284,24 +280,23 @@ public void testMultiNested() throws Exception {
     }
 
     public void testMultiObjectAndNested1() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -351,7 +346,7 @@ public void testMultiObjectAndNested1() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -378,25 +373,24 @@ public void testMultiObjectAndNested1() throws Exception {
     }
 
     public void testMultiObjectAndNested2() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_parent", true)
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_parent", true)
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -446,7 +440,7 @@ public void testMultiObjectAndNested2() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -473,24 +467,23 @@ public void testMultiObjectAndNested2() throws Exception {
     }
 
     public void testMultiRootAndNested1() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -540,7 +533,7 @@ public void testMultiRootAndNested1() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -574,27 +567,26 @@ public void testMultiRootAndNested1() throws Exception {
     public void testMultipleLevelsIncludeRoot1() throws Exception {
         MapperService mapperService = createIndex("test").mapperService();
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MergeReason mergeReason = randomFrom(MergeReason.MAPPING_UPDATE, MergeReason.INDEX_TEMPLATE);
 
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), mergeReason);
@@ -618,7 +610,7 @@ public void testMultipleLevelsIncludeRoot1() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -636,34 +628,33 @@ public void testMultipleLevelsIncludeRoot1() throws Exception {
     public void testMultipleLevelsIncludeRoot2() throws Exception {
         MapperService mapperService = createIndex("test").mapperService();
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", false)
-                .startObject("properties")
-                .startObject("nested3")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", false)
+            .startObject("properties")
+            .startObject("nested3")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MergeReason mergeReason = randomFrom(MergeReason.MAPPING_UPDATE, MergeReason.INDEX_TEMPLATE);
 
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), mergeReason);
@@ -691,7 +682,7 @@ public void testMultipleLevelsIncludeRoot2() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -707,48 +698,46 @@ public void testMultipleLevelsIncludeRoot2() throws Exception {
     public void testMultipleLevelsIncludeRootWithMerge() throws Exception {
         MapperService mapperService = createIndex("test").mapperService();
 
-        String firstMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String firstMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(firstMapping), MergeReason.INDEX_TEMPLATE);
 
-        String secondMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .field("include_in_parent", true)
-                .startObject("properties")
-                .startObject("nested2")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String secondMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .field("include_in_parent", true)
+            .startObject("properties")
+            .startObject("nested2")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(secondMapping), MergeReason.INDEX_TEMPLATE);
         DocumentMapper docMapper = mapperService.documentMapper();
@@ -771,7 +760,7 @@ public void testMultipleLevelsIncludeRootWithMerge() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -780,24 +769,23 @@ public void testMultipleLevelsIncludeRootWithMerge() throws Exception {
     }
 
     public void testNestedArrayStrict() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("dynamic", "strict")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("dynamic", "strict")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -826,7 +814,7 @@ public void testNestedArrayStrict() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -841,23 +829,22 @@ public void testNestedArrayStrict() throws Exception {
     public void testLimitOfNestedFieldsPerIndex() throws Exception {
         Function<String, String> mapping = type -> {
             try {
-                return Strings.toString(
-                    XContentFactory.jsonBuilder()
-                        .startObject()
-                        .startObject(type)
-                        .startObject("properties")
-                        .startObject("nested1")
-                        .field("type", "nested")
-                        .startObject("properties")
-                        .startObject("nested2")
-                        .field("type", "nested")
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                );
+                return XContentFactory.jsonBuilder()
+                    .startObject()
+                    .startObject(type)
+                    .startObject("properties")
+                    .startObject("nested1")
+                    .field("type", "nested")
+                    .startObject("properties")
+                    .startObject("nested2")
+                    .field("type", "nested")
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .endObject()
+                    .toString();
             } catch (IOException e) {
                 throw new UncheckedIOException(e);
             }
@@ -935,18 +922,17 @@ public void testParentObjectMapperAreNested() throws Exception {
     public void testLimitNestedDocsDefaultSettings() throws Exception {
         Settings settings = Settings.builder().build();
         MapperService mapperService = createIndex("test1", settings).mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper docMapper = mapperService.documentMapperParser().parse("type", new CompressedXContent(mapping));
         long defaultMaxNoNestedDocs = MapperService.INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING.get(settings);
 
@@ -963,7 +949,7 @@ public void testLimitNestedDocsDefaultSettings() throws Exception {
             docBuilder.endArray();
         }
         docBuilder.endObject();
-        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), XContentType.JSON);
+        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), MediaTypeRegistry.JSON);
         MapperParsingException e = expectThrows(MapperParsingException.class, () -> docMapper.parse(source1));
         assertEquals(
             "The number of nested documents has exceeded the allowed limit of ["
@@ -982,18 +968,17 @@ public void testLimitNestedDocs() throws Exception {
             "test1",
             Settings.builder().put(MapperService.INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING.getKey(), maxNoNestedDocs).build()
         ).mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper docMapper = mapperService.documentMapperParser().parse("type", new CompressedXContent(mapping));
 
         // parsing a doc with 2 nested objects succeeds
@@ -1008,7 +993,7 @@ public void testLimitNestedDocs() throws Exception {
             docBuilder.endArray();
         }
         docBuilder.endObject();
-        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), XContentType.JSON);
+        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), MediaTypeRegistry.JSON);
         ParsedDocument doc = docMapper.parse(source1);
         assertThat(doc.docs().size(), equalTo(3));
 
@@ -1025,7 +1010,7 @@ public void testLimitNestedDocs() throws Exception {
             docBuilder2.endArray();
         }
         docBuilder2.endObject();
-        SourceToParse source2 = new SourceToParse("test1", "2", BytesReference.bytes(docBuilder2), XContentType.JSON);
+        SourceToParse source2 = new SourceToParse("test1", "2", BytesReference.bytes(docBuilder2), MediaTypeRegistry.JSON);
         MapperParsingException e = expectThrows(MapperParsingException.class, () -> docMapper.parse(source2));
         assertEquals(
             "The number of nested documents has exceeded the allowed limit of ["
@@ -1044,21 +1029,20 @@ public void testLimitNestedDocsMultipleNestedFields() throws Exception {
             "test1",
             Settings.builder().put(MapperService.INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING.getKey(), maxNoNestedDocs).build()
         ).mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .endObject()
-                .startObject("nested2")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .endObject()
+            .startObject("nested2")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper docMapper = mapperService.documentMapperParser().parse("type", new CompressedXContent(mapping));
 
         // parsing a doc with 2 nested objects succeeds
@@ -1077,7 +1061,7 @@ public void testLimitNestedDocsMultipleNestedFields() throws Exception {
             docBuilder.endArray();
         }
         docBuilder.endObject();
-        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), XContentType.JSON);
+        SourceToParse source1 = new SourceToParse("test1", "1", BytesReference.bytes(docBuilder), MediaTypeRegistry.JSON);
         ParsedDocument doc = docMapper.parse(source1);
         assertThat(doc.docs().size(), equalTo(3));
 
@@ -1099,7 +1083,7 @@ public void testLimitNestedDocsMultipleNestedFields() throws Exception {
 
         }
         docBuilder2.endObject();
-        SourceToParse source2 = new SourceToParse("test1", "2", BytesReference.bytes(docBuilder2), XContentType.JSON);
+        SourceToParse source2 = new SourceToParse("test1", "2", BytesReference.bytes(docBuilder2), MediaTypeRegistry.JSON);
         MapperParsingException e = expectThrows(MapperParsingException.class, () -> docMapper.parse(source2));
         assertEquals(
             "The number of nested documents has exceeded the allowed limit of ["
@@ -1133,19 +1117,18 @@ public void testMergeNestedMappings() throws IOException {
                 .endObject()
         ).mapperService();
 
-        String mapping1 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_parent", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping1 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_parent", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         // cannot update `include_in_parent` dynamically
         MapperException e1 = expectThrows(
@@ -1154,19 +1137,18 @@ public void testMergeNestedMappings() throws IOException {
         );
         assertEquals("the [include_in_parent] parameter can't be updated on a nested object mapping", e1.getMessage());
 
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("nested1")
-                .field("type", "nested")
-                .field("include_in_root", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("nested1")
+            .field("type", "nested")
+            .field("include_in_root", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         // cannot update `include_in_root` dynamically
         MapperException e2 = expectThrows(
diff --git a/server/src/test/java/org/opensearch/index/mapper/NestedPathFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/NestedPathFieldMapperTests.java
new file mode 100644
index 0000000000000..06086e1c38466
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/mapper/NestedPathFieldMapperTests.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.mapper;
+
+import org.apache.lucene.index.IndexableField;
+import org.opensearch.common.compress.CompressedXContent;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+
+/** tests for {@link org.opensearch.index.mapper.NestedPathFieldMapper} */
+public class NestedPathFieldMapperTests extends OpenSearchSingleNodeTestCase {
+
+    public void testDefaultConfig() throws IOException {
+        Settings indexSettings = Settings.EMPTY;
+        MapperService mapperService = createIndex("test", indexSettings).mapperService();
+        DocumentMapper mapper = mapperService.merge(
+            MapperService.SINGLE_MAPPING_NAME,
+            new CompressedXContent("{\"" + MapperService.SINGLE_MAPPING_NAME + "\":{}}"),
+            MapperService.MergeReason.MAPPING_UPDATE
+        );
+        ParsedDocument document = mapper.parse(new SourceToParse("index", "id", new BytesArray("{}"), MediaTypeRegistry.JSON));
+        assertEquals(Collections.<IndexableField>emptyList(), Arrays.asList(document.rootDoc().getFields(NestedPathFieldMapper.NAME)));
+    }
+
+    public void testUpdatesWithSameMappings() throws IOException {
+        Settings indexSettings = Settings.EMPTY;
+        MapperService mapperService = createIndex("test", indexSettings).mapperService();
+        DocumentMapper mapper = mapperService.merge(
+            MapperService.SINGLE_MAPPING_NAME,
+            new CompressedXContent("{\"" + MapperService.SINGLE_MAPPING_NAME + "\":{}}"),
+            MapperService.MergeReason.MAPPING_UPDATE
+        );
+        mapper.merge(mapper.mapping(), MapperService.MergeReason.MAPPING_UPDATE);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/mapper/NullValueObjectMappingTests.java b/server/src/test/java/org/opensearch/index/mapper/NullValueObjectMappingTests.java
index 95c21823bfcae..eb0ef25f793ef 100644
--- a/server/src/test/java/org/opensearch/index/mapper/NullValueObjectMappingTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/NullValueObjectMappingTests.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
@@ -45,18 +44,17 @@
 
 public class NullValueObjectMappingTests extends OpenSearchSingleNodeTestCase {
     public void testNullValueObject() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("obj1")
-                .field("type", "object")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("obj1")
+            .field("type", "object")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -69,7 +67,7 @@ public void testNullValueObject() throws IOException {
                 BytesReference.bytes(
                     XContentFactory.jsonBuilder().startObject().startObject("obj1").endObject().field("value1", "test1").endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -80,7 +78,7 @@ public void testNullValueObject() throws IOException {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().nullField("obj1").field("value1", "test1").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -99,7 +97,7 @@ public void testNullValueObject() throws IOException {
                         .field("value1", "test1")
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/NullValueTests.java b/server/src/test/java/org/opensearch/index/mapper/NullValueTests.java
index b34cdcaed57b9..641edeb46354c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/NullValueTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/NullValueTests.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.util.Collections;
 
@@ -56,7 +55,7 @@ public void testNullNullValue() throws Exception {
             XContentBuilder b = JsonXContent.contentBuilder().startObject();
             mapper.mapping().toXContent(b, params);
             b.endObject();
-            assertThat(Strings.toString(b), containsString("\"null_value\":null"));
+            assertThat(b.toString(), containsString("\"null_value\":null"));
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/NumberFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/NumberFieldMapperTests.java
index 81d4d8b994ee3..610b69a7fdf88 100644
--- a/server/src/test/java/org/opensearch/index/mapper/NumberFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/NumberFieldMapperTests.java
@@ -34,10 +34,9 @@
 
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.NumberFieldMapper.NumberType;
 import org.opensearch.index.mapper.NumberFieldTypeTests.OutOfRangeSpec;
 import org.opensearch.index.termvectors.TermVectorsService;
@@ -55,12 +54,12 @@ public class NumberFieldMapperTests extends AbstractNumericFieldMapperTestCase {
 
     @Override
     protected Set<String> types() {
-        return org.opensearch.common.collect.Set.of("byte", "short", "integer", "long", "float", "double", "half_float");
+        return Set.of("byte", "short", "integer", "long", "float", "double", "half_float", "unsigned_long");
     }
 
     @Override
     protected Set<String> wholeTypes() {
-        return org.opensearch.common.collect.Set.of("byte", "short", "integer", "long");
+        return Set.of("byte", "short", "integer", "long", "unsigned_long");
     }
 
     @Override
@@ -95,7 +94,7 @@ public void testExistsQueryDocValuesDisabled() throws IOException {
     public void doTestDefaults(String type) throws Exception {
         XContentBuilder mapping = fieldMapping(b -> b.field("type", type));
         DocumentMapper mapper = createDocumentMapper(mapping);
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("field", 123)));
 
@@ -147,7 +146,12 @@ public void doTestStore(String type) throws Exception {
         assertEquals(DocValuesType.SORTED_NUMERIC, dvField.fieldType().docValuesType());
         IndexableField storedField = fields[2];
         assertTrue(storedField.fieldType().stored());
-        assertEquals(123, storedField.numericValue().doubleValue(), 0d);
+        // The 'unsigned_long' is stored as a string
+        if (type.equalsIgnoreCase("unsigned_long")) {
+            assertEquals(123, new BigInteger(storedField.stringValue()).longValue());
+        } else {
+            assertEquals(123, storedField.numericValue().doubleValue(), 0d);
+        }
     }
 
     @Override
@@ -244,22 +248,26 @@ public void testOutOfRangeValues() throws IOException {
             OutOfRangeSpec.of(NumberType.INTEGER, "2147483648", "is out of range for an integer"),
             OutOfRangeSpec.of(NumberType.LONG, "9223372036854775808", "out of range for a long"),
             OutOfRangeSpec.of(NumberType.LONG, "1e999999999", "out of range for a long"),
+            OutOfRangeSpec.of(NumberType.UNSIGNED_LONG, "18446744073709551616", "out of range for an unsigned long"),
 
             OutOfRangeSpec.of(NumberType.BYTE, "-129", "is out of range for a byte"),
             OutOfRangeSpec.of(NumberType.SHORT, "-32769", "is out of range for a short"),
             OutOfRangeSpec.of(NumberType.INTEGER, "-2147483649", "is out of range for an integer"),
             OutOfRangeSpec.of(NumberType.LONG, "-9223372036854775809", "out of range for a long"),
             OutOfRangeSpec.of(NumberType.LONG, "-1e999999999", "out of range for a long"),
+            OutOfRangeSpec.of(NumberType.UNSIGNED_LONG, "-1", "out of range for an unsigned long"),
 
             OutOfRangeSpec.of(NumberType.BYTE, 128, "is out of range for a byte"),
             OutOfRangeSpec.of(NumberType.SHORT, 32768, "out of range of Java short"),
             OutOfRangeSpec.of(NumberType.INTEGER, 2147483648L, " out of range of int"),
             OutOfRangeSpec.of(NumberType.LONG, new BigInteger("9223372036854775808"), "out of range of long"),
+            OutOfRangeSpec.of(NumberType.UNSIGNED_LONG, new BigInteger("18446744073709551616"), "out of range for an unsigned long"),
 
             OutOfRangeSpec.of(NumberType.BYTE, -129, "is out of range for a byte"),
             OutOfRangeSpec.of(NumberType.SHORT, -32769, "out of range of Java short"),
             OutOfRangeSpec.of(NumberType.INTEGER, -2147483649L, " out of range of int"),
             OutOfRangeSpec.of(NumberType.LONG, new BigInteger("-9223372036854775809"), "out of range of long"),
+            OutOfRangeSpec.of(NumberType.UNSIGNED_LONG, new BigInteger("-1"), "out of range for an unsigned long"),
 
             OutOfRangeSpec.of(NumberType.HALF_FLOAT, "65520", "[half_float] supports only finite values"),
             OutOfRangeSpec.of(NumberType.FLOAT, "3.4028235E39", "[float] supports only finite values"),
@@ -307,7 +315,7 @@ public void testOutOfRangeValues() throws IOException {
     public void testLongIndexingOutOfRange() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "long").field("ignore_malformed", true)));
         ParsedDocument doc = mapper.parse(
-            source(b -> b.rawField("field", new BytesArray("9223372036854775808").streamInput(), XContentType.JSON))
+            source(b -> b.rawField("field", new BytesArray("9223372036854775808").streamInput(), MediaTypeRegistry.JSON))
         );
         assertEquals(0, doc.rootDoc().getFields("field").length);
     }
diff --git a/server/src/test/java/org/opensearch/index/mapper/NumberFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/NumberFieldTypeTests.java
index 868261130135c..3c30bb81a9a32 100644
--- a/server/src/test/java/org/opensearch/index/mapper/NumberFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/NumberFieldTypeTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.index.mapper;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.DoublePoint;
 import org.apache.lucene.document.FloatPoint;
@@ -42,25 +43,29 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
 import org.apache.lucene.sandbox.document.HalfFloatPoint;
-import org.apache.lucene.sandbox.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.IndexOrDocValuesQuery;
 import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.IndexSortSortedNumericDocValuesRangeQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.NumericUtils;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.document.SortedUnsignedLongDocValuesRangeQuery;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.mapper.MappedFieldType.Relation;
 import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
@@ -342,7 +347,27 @@ public void testLongRangeQueryWithDecimalParts() {
         );
     }
 
-    public void testRangeQuery() {
+    public void testUnsignedLongRangeQueryWithDecimalParts() {
+        MappedFieldType ft = new NumberFieldMapper.NumberFieldType("field", NumberType.UNSIGNED_LONG);
+        assertEquals(
+            ft.rangeQuery(2, 10, true, true, null, null, null, MOCK_QSC),
+            ft.rangeQuery(1.1, 10, true, true, null, null, null, MOCK_QSC)
+        );
+        assertEquals(
+            ft.rangeQuery(2, 10, true, true, null, null, null, MOCK_QSC),
+            ft.rangeQuery(1.1, 10, false, true, null, null, null, MOCK_QSC)
+        );
+        assertEquals(
+            ft.rangeQuery(1, 10, true, true, null, null, null, MOCK_QSC),
+            ft.rangeQuery(1, 10.1, true, true, null, null, null, MOCK_QSC)
+        );
+        assertEquals(
+            ft.rangeQuery(1, 10, true, true, null, null, null, MOCK_QSC),
+            ft.rangeQuery(1, 10.1, true, false, null, null, null, MOCK_QSC)
+        );
+    }
+
+    public void testLongRangeQuery() {
         MappedFieldType ft = new NumberFieldMapper.NumberFieldType("field", NumberFieldMapper.NumberType.LONG);
         Query expected = new IndexOrDocValuesQuery(
             LongPoint.newRangeQuery("field", 1, 3),
@@ -358,11 +383,48 @@ public void testRangeQuery() {
         assertEquals("Cannot search on field [field] since it is not indexed.", e.getMessage());
     }
 
+    public void testUnsignedLongRangeQuery() {
+        MappedFieldType ft = new NumberFieldMapper.NumberFieldType("field", NumberFieldMapper.NumberType.UNSIGNED_LONG);
+        Query expected = new IndexOrDocValuesQuery(
+            BigIntegerPoint.newRangeQuery("field", BigInteger.valueOf(1), BigInteger.valueOf(3)),
+            SortedUnsignedLongDocValuesRangeQuery.newSlowRangeQuery("field", BigInteger.valueOf(1), BigInteger.valueOf(3))
+        );
+        assertEquals(expected, ft.rangeQuery("1", "3", true, true, null, null, null, MOCK_QSC));
+
+        MappedFieldType unsearchable = unsearchable();
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> unsearchable.rangeQuery("1", "3", true, true, null, null, null, MOCK_QSC)
+        );
+        assertEquals("Cannot search on field [field] since it is not indexed.", e.getMessage());
+    }
+
+    public void testDoubleRangeQuery() {
+        MappedFieldType ft = new NumberFieldMapper.NumberFieldType("field", NumberFieldMapper.NumberType.DOUBLE);
+        Query expected = new IndexOrDocValuesQuery(
+            DoublePoint.newRangeQuery("field", 1d, 3d),
+            SortedNumericDocValuesField.newSlowRangeQuery(
+                "field",
+                NumericUtils.doubleToSortableLong(1),
+                NumericUtils.doubleToSortableLong(3)
+            )
+        );
+        assertEquals(expected, ft.rangeQuery("1", "3", true, true, null, null, null, MOCK_QSC));
+
+        MappedFieldType unsearchable = unsearchable();
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> unsearchable.rangeQuery("1", "3", true, true, null, null, null, MOCK_QSC)
+        );
+        assertEquals("Cannot search on field [field] since it is not indexed.", e.getMessage());
+    }
+
     public void testConversions() {
         assertEquals((byte) 3, NumberType.BYTE.parse(3d, true));
         assertEquals((short) 3, NumberType.SHORT.parse(3d, true));
         assertEquals(3, NumberType.INTEGER.parse(3d, true));
         assertEquals(3L, NumberType.LONG.parse(3d, true));
+        assertEquals(BigInteger.valueOf(3L), NumberType.UNSIGNED_LONG.parse(3d, true));
         assertEquals(3f, NumberType.HALF_FLOAT.parse(3d, true));
         assertEquals(3f, NumberType.FLOAT.parse(3d, true));
         assertEquals(3d, NumberType.DOUBLE.parse(3d, true));
@@ -371,6 +433,7 @@ public void testConversions() {
         assertEquals((short) 3, NumberType.SHORT.parse(3.5, true));
         assertEquals(3, NumberType.INTEGER.parse(3.5, true));
         assertEquals(3L, NumberType.LONG.parse(3.5, true));
+        assertEquals(BigInteger.valueOf(3L), NumberType.UNSIGNED_LONG.parse(3.5, true));
 
         assertEquals(3.5f, NumberType.FLOAT.parse(3.5, true));
         assertEquals(3.5d, NumberType.DOUBLE.parse(3.5, true));
@@ -383,6 +446,8 @@ public void testConversions() {
         assertEquals("Value [2147483648] is out of range for an integer", e.getMessage());
         e = expectThrows(IllegalArgumentException.class, () -> NumberType.LONG.parse(10000000000000000000d, true));
         assertEquals("Value [1.0E19] is out of range for a long", e.getMessage());
+        e = expectThrows(IllegalArgumentException.class, () -> NumberType.UNSIGNED_LONG.parse(100000000000000000000d, true));
+        assertEquals("Value [1.0E20] is out of range for an unsigned long", e.getMessage());
         assertEquals(1.1f, NumberType.HALF_FLOAT.parse(1.1, true));
         assertEquals(1.1f, NumberType.FLOAT.parse(1.1, true));
         assertEquals(1.1d, NumberType.DOUBLE.parse(1.1, true));
@@ -417,6 +482,13 @@ public void testCoercions() {
         // these will lose precision if they get treated as a double
         assertEquals(-4115420654264075766L, NumberType.LONG.parse("-4115420654264075766", true));
         assertEquals(-4115420654264075766L, NumberType.LONG.parse(-4115420654264075766L, true));
+
+        assertEquals(BigInteger.valueOf(5), NumberType.UNSIGNED_LONG.parse((byte) 5, true));
+        assertEquals(BigInteger.valueOf(5), NumberType.UNSIGNED_LONG.parse("5", true));
+        assertEquals(BigInteger.valueOf(5), NumberType.UNSIGNED_LONG.parse("5.0", true));
+        assertEquals(BigInteger.valueOf(5), NumberType.UNSIGNED_LONG.parse("5.9", true));
+        assertEquals(BigInteger.valueOf(5), NumberType.UNSIGNED_LONG.parse(new BytesRef("5.3".getBytes(StandardCharsets.UTF_8)), true));
+        assertEquals(Numbers.MAX_UNSIGNED_LONG_VALUE, NumberType.UNSIGNED_LONG.parse(Numbers.MAX_UNSIGNED_LONG_VALUE, true));
     }
 
     public void testHalfFloatRange() throws IOException {
@@ -453,6 +525,37 @@ public void testHalfFloatRange() throws IOException {
         IOUtils.close(reader, dir);
     }
 
+    public void testUnsignedLongRange() throws IOException {
+        // make sure the accuracy loss of half floats only occurs at index time
+        // this test checks that searching half floats yields the same results as
+        // searching floats that are rounded to the closest half float
+        Directory dir = newDirectory();
+        IndexWriter w = new IndexWriter(dir, new IndexWriterConfig(null));
+        final int numDocs = 10000;
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            BigInteger value = randomUnsignedLong();
+            doc.add(new BigIntegerPoint("unsigned_long", value));
+            doc.add(new DoublePoint("double", value.doubleValue()));
+            w.addDocument(doc);
+        }
+        final DirectoryReader reader = DirectoryReader.open(w);
+        w.close();
+
+        IndexSearcher searcher = newSearcher(reader);
+        final int numQueries = 1000;
+        for (int i = 0; i < numQueries; ++i) {
+            BigInteger l = randomUnsignedLong();
+            BigInteger u = randomUnsignedLong();
+            boolean includeLower = randomBoolean();
+            boolean includeUpper = randomBoolean();
+            Query unsignedLongQ = NumberType.UNSIGNED_LONG.rangeQuery("unsigned_long", l, u, includeLower, includeUpper, false, MOCK_QSC);
+            Query doubleQ = NumberType.DOUBLE.rangeQuery("double", l, u, includeLower, includeUpper, false, MOCK_QSC);
+            assertEquals(searcher.count(doubleQ), searcher.count(unsignedLongQ));
+        }
+        IOUtils.close(reader, dir);
+    }
+
     public void testNegativeZero() {
         assertEquals(
             NumberType.DOUBLE.rangeQuery("field", null, -0d, true, true, false, MOCK_QSC),
@@ -490,6 +593,10 @@ public void testDocValueLongRange() throws Exception {
         doTestDocValueRangeQueries(NumberType.LONG, random()::nextLong);
     }
 
+    public void testDocValueUnsignedLongRange() throws Exception {
+        doTestDocValueRangeQueries(NumberType.UNSIGNED_LONG, FieldTypeTestCase::randomUnsignedLong);
+    }
+
     public void testDocValueHalfFloatRange() throws Exception {
         doTestDocValueRangeQueries(NumberType.HALF_FLOAT, random()::nextFloat);
     }
@@ -553,10 +660,9 @@ public void doTestIndexSortRangeQueries(NumberType type, Supplier<Number> valueS
 
         // Create an index writer configured with the same index sort.
         NumberFieldType fieldType = new NumberFieldType("field", type);
-        IndexNumericFieldData fielddata = (IndexNumericFieldData) fieldType.fielddataBuilder(
-            "index",
-            () -> { throw new UnsupportedOperationException(); }
-        ).build(null, null);
+        IndexNumericFieldData fielddata = (IndexNumericFieldData) fieldType.fielddataBuilder("index", () -> {
+            throw new UnsupportedOperationException();
+        }).build(null, null);
         SortField sortField = fielddata.sortField(null, MultiValueMode.MIN, null, randomBoolean());
 
         IndexWriterConfig writerConfig = new IndexWriterConfig();
@@ -693,7 +799,7 @@ static OutOfRangeSpec of(NumberType t, Object v, String m) {
 
         public void write(XContentBuilder b) throws IOException {
             if (value instanceof BigInteger) {
-                b.rawField("field", new ByteArrayInputStream(value.toString().getBytes("UTF-8")), XContentType.JSON);
+                b.rawField("field", new ByteArrayInputStream(value.toString().getBytes("UTF-8")), MediaTypeRegistry.JSON);
             } else {
                 b.field("field", value);
             }
diff --git a/server/src/test/java/org/opensearch/index/mapper/ObjectMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/ObjectMapperTests.java
index 079475d9f3554..be947935dc4ea 100644
--- a/server/src/test/java/org/opensearch/index/mapper/ObjectMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/ObjectMapperTests.java
@@ -32,16 +32,15 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.index.mapper.ObjectMapper.Dynamic;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -50,7 +49,7 @@
 
 public class ObjectMapperTests extends OpenSearchSingleNodeTestCase {
     public void testDifferentInnerObjectTokenFailure() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -75,7 +74,7 @@ public void testDifferentInnerObjectTokenFailure() throws Exception {
                             + "      \"value\":\"value\"\n"
                             + "    }"
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         });
@@ -83,51 +82,54 @@ public void testDifferentInnerObjectTokenFailure() throws Exception {
     }
 
     public void testEmptyArrayProperties() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").startArray("properties").endArray().endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startArray("properties")
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
         createIndex("test").mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
     }
 
     public void testEmptyFieldsArrayMultiFields() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("tweet")
-                .startObject("properties")
-                .startObject("name")
-                .field("type", "text")
-                .startArray("fields")
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("tweet")
+            .startObject("properties")
+            .startObject("name")
+            .field("type", "text")
+            .startArray("fields")
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
     }
 
     public void testFieldsArrayMultiFieldsShouldThrowException() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("tweet")
-                .startObject("properties")
-                .startObject("name")
-                .field("type", "text")
-                .startArray("fields")
-                .startObject()
-                .field("test", "string")
-                .endObject()
-                .startObject()
-                .field("test2", "string")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("tweet")
+            .startObject("properties")
+            .startObject("name")
+            .field("type", "text")
+            .startArray("fields")
+            .startObject()
+            .field("test", "string")
+            .endObject()
+            .startObject()
+            .field("test2", "string")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         try {
             createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
             fail("Expected MapperParsingException");
@@ -138,38 +140,36 @@ public void testFieldsArrayMultiFieldsShouldThrowException() throws Exception {
     }
 
     public void testEmptyFieldsArray() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("tweet")
-                .startObject("properties")
-                .startArray("fields")
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("tweet")
+            .startObject("properties")
+            .startArray("fields")
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
     }
 
     public void testFieldsWithFilledArrayShouldThrowException() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("tweet")
-                .startObject("properties")
-                .startArray("fields")
-                .startObject()
-                .field("test", "string")
-                .endObject()
-                .startObject()
-                .field("test2", "string")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("tweet")
+            .startObject("properties")
+            .startArray("fields")
+            .startObject()
+            .field("test", "string")
+            .endObject()
+            .startObject()
+            .field("test2", "string")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         try {
             createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
             fail("Expected MapperParsingException");
@@ -178,79 +178,98 @@ public void testFieldsWithFilledArrayShouldThrowException() throws Exception {
         }
     }
 
+    public void testDotAsFieldName() throws Exception {
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject(".")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+
+        try {
+            createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
+            fail("Expected MapperParsingException");
+        } catch (MapperParsingException e) {
+            assertThat(e.getMessage(), containsString("Invalid field name"));
+        }
+    }
+
     public void testFieldPropertiesArray() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("tweet")
-                .startObject("properties")
-                .startObject("name")
-                .field("type", "text")
-                .startObject("fields")
-                .startObject("raw")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("tweet")
+            .startObject("properties")
+            .startObject("name")
+            .field("type", "text")
+            .startObject("fields")
+            .startObject("raw")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         createIndex("test").mapperService().documentMapperParser().parse("tweet", new CompressedXContent(mapping));
     }
 
     public void testMerge() throws IOException {
         MergeReason reason = randomFrom(MergeReason.values());
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), reason);
         assertNull(mapper.root().dynamic());
-        String update = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").field("dynamic", "strict").endObject().endObject()
-        );
+        String update = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("dynamic", "strict")
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(update), reason);
         assertEquals(Dynamic.STRICT, mapper.root().dynamic());
     }
 
     public void testMergeEnabledForIndexTemplates() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .field("type", "object")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .field("type", "object")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), MergeReason.INDEX_TEMPLATE);
         assertNull(mapper.root().dynamic());
 
         // If we don't explicitly set 'enabled', then the mapping should not change.
-        String update = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .field("type", "object")
-                .field("dynamic", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String update = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .field("type", "object")
+            .field("dynamic", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(update), MergeReason.INDEX_TEMPLATE);
 
         ObjectMapper objectMapper = mapper.objectMappers().get("object");
@@ -258,17 +277,16 @@ public void testMergeEnabledForIndexTemplates() throws IOException {
         assertFalse(objectMapper.isEnabled());
 
         // Setting 'enabled' to true is allowed, and updates the mapping.
-        update = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .field("type", "object")
-                .field("enabled", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        update = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .field("type", "object")
+            .field("enabled", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(update), MergeReason.INDEX_TEMPLATE);
 
         objectMapper = mapper.objectMappers().get("object");
@@ -278,129 +296,123 @@ public void testMergeEnabledForIndexTemplates() throws IOException {
 
     public void testFieldReplacementForIndexTemplates() throws IOException {
         MapperService mapperService = createIndex("test").mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("field2")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("field2")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), MergeReason.INDEX_TEMPLATE);
 
-        String update = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field2")
-                .field("type", "integer")
-                .endObject()
-                .startObject("field3")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String update = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field2")
+            .field("type", "integer")
+            .endObject()
+            .startObject("field3")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper mapper = mapperService.merge(
             MapperService.SINGLE_MAPPING_NAME,
             new CompressedXContent(update),
             MergeReason.INDEX_TEMPLATE
         );
 
-        String expected = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject(MapperService.SINGLE_MAPPING_NAME)
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("field2")
-                .field("type", "integer")
-                .endObject()
-                .startObject("field3")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String expected = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject(MapperService.SINGLE_MAPPING_NAME)
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("field2")
+            .field("type", "integer")
+            .endObject()
+            .startObject("field3")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         assertEquals(expected, mapper.mappingSource().toString());
     }
 
     public void testDisallowFieldReplacementForIndexTemplates() throws IOException {
         MapperService mapperService = createIndex("test").mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "object")
-                .endObject()
-                .startObject("field2")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "object")
+            .endObject()
+            .startObject("field2")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), MergeReason.INDEX_TEMPLATE);
 
-        String firstUpdate = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field2")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String firstUpdate = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field2")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
             () -> mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(firstUpdate), MergeReason.INDEX_TEMPLATE)
         );
         assertThat(e.getMessage(), containsString("can't merge a non object mapping [object.field2] with an object mapping"));
 
-        String secondUpdate = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("object")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String secondUpdate = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("object")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         e = expectThrows(
             IllegalArgumentException.class,
             () -> mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(secondUpdate), MergeReason.INDEX_TEMPLATE)
@@ -409,24 +421,22 @@ public void testDisallowFieldReplacementForIndexTemplates() throws IOException {
     }
 
     public void testEmptyName() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("")
-                .startObject("properties")
-                .startObject("name")
-                .field("type", "text")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("")
+            .startObject("properties")
+            .startObject("name")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         // Empty name not allowed in index created after 5.0
-        IllegalArgumentException e = expectThrows(
-            IllegalArgumentException.class,
-            () -> { createIndex("test").mapperService().documentMapperParser().parse("", new CompressedXContent(mapping)); }
-        );
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            createIndex("test").mapperService().documentMapperParser().parse("", new CompressedXContent(mapping));
+        });
         assertThat(e.getMessage(), containsString("name cannot be empty string"));
     }
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/ParametrizedMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/ParametrizedMapperTests.java
index f6489d264a6d3..67150b6d02411 100644
--- a/server/src/test/java/org/opensearch/index/mapper/ParametrizedMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/ParametrizedMapperTests.java
@@ -35,14 +35,15 @@
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -68,7 +69,7 @@ public class ParametrizedMapperTests extends MapperServiceTestCase {
     public static class TestPlugin extends Plugin implements MapperPlugin {
         @Override
         public Map<String, Mapper.TypeParser> getMappers() {
-            return org.opensearch.common.collect.Map.of("test_mapper", new TypeParser());
+            return Map.of("test_mapper", new TypeParser());
         }
     }
 
@@ -218,7 +219,7 @@ protected String contentType() {
     private static TestMapper fromMapping(String mapping, Version version) {
         MapperService mapperService = mock(MapperService.class);
         IndexAnalyzers indexAnalyzers = new IndexAnalyzers(
-            org.opensearch.common.collect.Map.of(
+            Map.of(
                 "_standard",
                 Lucene.STANDARD_ANALYZER,
                 "_keyword",
@@ -253,7 +254,7 @@ private String toStringWithDefaults(ToXContent value) throws IOException {
         builder.startObject();
         value.toXContent(builder, params);
         builder.endObject();
-        return Strings.toString(builder);
+        return builder.toString();
 
     }
 
@@ -265,7 +266,7 @@ public void testDefaults() throws IOException {
         assertTrue(mapper.fixed);
         assertEquals("default", mapper.variable);
 
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
         assertEquals(
             "{\"field\":{\"type\":\"test_mapper\",\"fixed\":true,"
                 + "\"fixed2\":false,\"variable\":\"default\",\"index\":true,"
@@ -279,7 +280,7 @@ public void testDefaults() throws IOException {
     public void testMerging() {
         String mapping = "{\"type\":\"test_mapper\",\"fixed\":false,\"required\":\"value\"}";
         TestMapper mapper = fromMapping(mapping);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         TestMapper badMerge = fromMapping("{\"type\":\"test_mapper\",\"fixed\":true,\"fixed2\":true,\"required\":\"value\"}");
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> mapper.merge(badMerge));
@@ -288,16 +289,20 @@ public void testMerging() {
             + "\tCannot update parameter [fixed2] from [false] to [true]";
         assertEquals(expectedError, e.getMessage());
 
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));   // original mapping is unaffected
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));   // original
+        // mapping is
+        // unaffected
 
         // TODO: should we have to include 'fixed' here? Or should updates take as 'defaults' the existing values?
         TestMapper goodMerge = fromMapping("{\"type\":\"test_mapper\",\"fixed\":false,\"variable\":\"updated\",\"required\":\"value\"}");
         TestMapper merged = (TestMapper) mapper.merge(goodMerge);
 
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));   // original mapping is unaffected
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));   // original
+        // mapping is
+        // unaffected
         assertEquals(
             "{\"field\":{\"type\":\"test_mapper\",\"fixed\":false,\"variable\":\"updated\",\"required\":\"value\"}}",
-            Strings.toString(merged)
+            Strings.toString(MediaTypeRegistry.JSON, merged)
         );
     }
 
@@ -306,7 +311,7 @@ public void testMultifields() {
         String mapping = "{\"type\":\"test_mapper\",\"variable\":\"foo\",\"required\":\"value\","
             + "\"fields\":{\"sub\":{\"type\":\"keyword\"}}}";
         TestMapper mapper = fromMapping(mapping);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String addSubField = "{\"type\":\"test_mapper\",\"variable\":\"foo\",\"required\":\"value\""
             + ",\"fields\":{\"sub2\":{\"type\":\"keyword\"}}}";
@@ -315,7 +320,7 @@ public void testMultifields() {
         assertEquals(
             "{\"field\":{\"type\":\"test_mapper\",\"variable\":\"foo\",\"required\":\"value\","
                 + "\"fields\":{\"sub\":{\"type\":\"keyword\"},\"sub2\":{\"type\":\"keyword\"}}}}",
-            Strings.toString(merged)
+            Strings.toString(MediaTypeRegistry.JSON, merged)
         );
 
         String badSubField = "{\"type\":\"test_mapper\",\"variable\":\"foo\",\"required\":\"value\","
@@ -329,7 +334,7 @@ public void testMultifields() {
     public void testCopyTo() {
         String mapping = "{\"type\":\"test_mapper\",\"variable\":\"foo\",\"required\":\"value\",\"copy_to\":[\"other\"]}";
         TestMapper mapper = fromMapping(mapping);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         // On update, copy_to is completely replaced
 
@@ -339,12 +344,15 @@ public void testCopyTo() {
         TestMapper merged = (TestMapper) mapper.merge(toMerge);
         assertEquals(
             "{\"field\":{\"type\":\"test_mapper\",\"variable\":\"updated\",\"required\":\"value\"," + "\"copy_to\":[\"foo\",\"bar\"]}}",
-            Strings.toString(merged)
+            Strings.toString(MediaTypeRegistry.JSON, merged)
         );
 
         TestMapper removeCopyTo = fromMapping("{\"type\":\"test_mapper\",\"variable\":\"updated\",\"required\":\"value\"}");
         TestMapper noCopyTo = (TestMapper) merged.merge(removeCopyTo);
-        assertEquals("{\"field\":{\"type\":\"test_mapper\",\"variable\":\"updated\",\"required\":\"value\"}}", Strings.toString(noCopyTo));
+        assertEquals(
+            "{\"field\":{\"type\":\"test_mapper\",\"variable\":\"updated\",\"required\":\"value\"}}",
+            Strings.toString(MediaTypeRegistry.JSON, noCopyTo)
+        );
     }
 
     public void testNullables() {
@@ -354,7 +362,7 @@ public void testNullables() {
 
         String fine = "{\"type\":\"test_mapper\",\"variable\":null,\"required\":\"value\"}";
         TestMapper mapper = fromMapping(fine);
-        assertEquals("{\"field\":" + fine + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + fine + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
     }
 
     public void testObjectSerialization() throws IOException {
@@ -369,10 +377,10 @@ public void testObjectSerialization() throws IOException {
             + "\"is_interim\":{\"type\":\"boolean\"}}}}}}";
 
         MapperService mapperService = createMapperService("_doc", mapping);
-        assertEquals(mapping, Strings.toString(mapperService.documentMapper()));
+        assertEquals(mapping, Strings.toString(MediaTypeRegistry.JSON, mapperService.documentMapper()));
 
         mapperService.merge("_doc", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
-        assertEquals(mapping, Strings.toString(mapperService.documentMapper()));
+        assertEquals(mapping, Strings.toString(MediaTypeRegistry.JSON, mapperService.documentMapper()));
     }
 
     // test custom serializer
@@ -380,7 +388,7 @@ public void testCustomSerialization() {
         String mapping = "{\"type\":\"test_mapper\",\"wrapper\":\"wrapped value\",\"required\":\"value\"}";
         TestMapper mapper = fromMapping(mapping);
         assertEquals("wrapped value", mapper.wrapper.name);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String conflict = "{\"type\":\"test_mapper\",\"wrapper\":\"new value\",\"required\":\"value\"}";
         TestMapper toMerge = fromMapping(conflict);
@@ -397,7 +405,7 @@ public void testParameterValidation() {
         String mapping = "{\"type\":\"test_mapper\",\"int_value\":10,\"required\":\"value\"}";
         TestMapper mapper = fromMapping(mapping);
         assertEquals(10, mapper.intValue);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
@@ -412,20 +420,23 @@ public void testDeprecatedParameterName() {
         TestMapper mapper = fromMapping(mapping);
         assertTrue(mapper.fixed2);
         assertWarnings("Parameter [fixed2_old] on mapper [field] is deprecated, use [fixed2]");
-        assertEquals("{\"field\":{\"type\":\"test_mapper\",\"fixed2\":true,\"required\":\"value\"}}", Strings.toString(mapper));
+        assertEquals(
+            "{\"field\":{\"type\":\"test_mapper\",\"fixed2\":true,\"required\":\"value\"}}",
+            Strings.toString(MediaTypeRegistry.JSON, mapper)
+        );
     }
 
     public void testAnalyzers() {
         String mapping = "{\"type\":\"test_mapper\",\"analyzer\":\"_standard\",\"required\":\"value\"}";
         TestMapper mapper = fromMapping(mapping);
         assertEquals(mapper.analyzer, Lucene.STANDARD_ANALYZER);
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String withDef = "{\"type\":\"test_mapper\",\"analyzer\":\"default\",\"required\":\"value\"}";
         mapper = fromMapping(withDef);
         assertEquals(mapper.analyzer.name(), "default");
         assertThat(mapper.analyzer.analyzer(), instanceOf(StandardAnalyzer.class));
-        assertEquals("{\"field\":" + withDef + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + withDef + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String badAnalyzer = "{\"type\":\"test_mapper\",\"analyzer\":\"wibble\",\"required\":\"value\"}";
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> fromMapping(badAnalyzer));
@@ -446,7 +457,10 @@ public void testDeprecatedParameters() {
         TestMapper mapper = fromMapping(mapping, LegacyESVersion.V_7_8_0);
         assertWarnings("Parameter [store] has no effect on type [test_mapper] and will be removed in future");
         assertFalse(mapper.index);
-        assertEquals("{\"field\":{\"type\":\"test_mapper\",\"index\":false,\"required\":\"value\"}}", Strings.toString(mapper));
+        assertEquals(
+            "{\"field\":{\"type\":\"test_mapper\",\"index\":false,\"required\":\"value\"}}",
+            Strings.toString(MediaTypeRegistry.JSON, mapper)
+        );
     }
 
     public void testLinkedAnalyzers() throws IOException {
@@ -454,20 +468,20 @@ public void testLinkedAnalyzers() throws IOException {
         TestMapper mapper = fromMapping(mapping);
         assertEquals("_standard", mapper.analyzer.name());
         assertEquals("_standard", mapper.searchAnalyzer.name());
-        assertEquals("{\"field\":" + mapping + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mapping + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String mappingWithSA = "{\"type\":\"test_mapper\",\"search_analyzer\":\"_standard\",\"required\":\"value\"}";
         mapper = fromMapping(mappingWithSA);
         assertEquals("_keyword", mapper.analyzer.name());
         assertEquals("_standard", mapper.searchAnalyzer.name());
-        assertEquals("{\"field\":" + mappingWithSA + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mappingWithSA + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         String mappingWithBoth = "{\"type\":\"test_mapper\",\"analyzer\":\"default\","
             + "\"search_analyzer\":\"_standard\",\"required\":\"value\"}";
         mapper = fromMapping(mappingWithBoth);
         assertEquals("default", mapper.analyzer.name());
         assertEquals("_standard", mapper.searchAnalyzer.name());
-        assertEquals("{\"field\":" + mappingWithBoth + "}", Strings.toString(mapper));
+        assertEquals("{\"field\":" + mappingWithBoth + "}", Strings.toString(MediaTypeRegistry.JSON, mapper));
 
         // we've configured things so that search_analyzer is only output when different from
         // analyzer, no matter what the value of `include_defaults` is
@@ -476,7 +490,10 @@ public void testLinkedAnalyzers() throws IOException {
         mapper = fromMapping(mappingWithSame);
         assertEquals("default", mapper.analyzer.name());
         assertEquals("default", mapper.searchAnalyzer.name());
-        assertEquals("{\"field\":{\"type\":\"test_mapper\",\"analyzer\":\"default\",\"required\":\"value\"}}", Strings.toString(mapper));
+        assertEquals(
+            "{\"field\":{\"type\":\"test_mapper\",\"analyzer\":\"default\",\"required\":\"value\"}}",
+            Strings.toString(MediaTypeRegistry.JSON, mapper)
+        );
 
         assertEquals(
             "{\"field\":{\"type\":\"test_mapper\",\"fixed\":true,"
diff --git a/server/src/test/java/org/opensearch/index/mapper/PathMatchDynamicTemplateTests.java b/server/src/test/java/org/opensearch/index/mapper/PathMatchDynamicTemplateTests.java
index e98dc399b3b41..1fed040a449e8 100644
--- a/server/src/test/java/org/opensearch/index/mapper/PathMatchDynamicTemplateTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/PathMatchDynamicTemplateTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.ParseContext.Document;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
@@ -47,17 +47,17 @@ public class PathMatchDynamicTemplateTests extends OpenSearchSingleNodeTestCase
     public void testSimple() throws Exception {
         String mapping = copyToStringFromClasspath("/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-mapping.json");
         IndexService index = createIndex("test");
-        client().admin().indices().preparePutMapping("test").setSource(mapping, XContentType.JSON).get();
+        client().admin().indices().preparePutMapping("test").setSource(mapping, MediaTypeRegistry.JSON).get();
 
         MapperService mapperService = index.mapperService();
 
         byte[] json = copyToBytesFromClasspath("/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-data.json");
         ParsedDocument parsedDoc = mapperService.documentMapper()
-            .parse(new SourceToParse("test", "1", new BytesArray(json), XContentType.JSON));
+            .parse(new SourceToParse("test", "1", new BytesArray(json), MediaTypeRegistry.JSON));
         client().admin()
             .indices()
             .preparePutMapping("test")
-            .setSource(parsedDoc.dynamicMappingsUpdate().toString(), XContentType.JSON)
+            .setSource(parsedDoc.dynamicMappingsUpdate().toString(), MediaTypeRegistry.JSON)
             .get();
         Document doc = parsedDoc.rootDoc();
 
diff --git a/server/src/test/java/org/opensearch/index/mapper/RangeFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/RangeFieldMapperTests.java
index 0353173e25696..4ebb160c07c8e 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RangeFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RangeFieldMapperTests.java
@@ -36,11 +36,10 @@
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
 import org.opensearch.common.network.InetAddresses;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 
 import java.io.IOException;
@@ -68,12 +67,12 @@ public class RangeFieldMapperTests extends AbstractNumericFieldMapperTestCase {
 
     @Override
     protected Set<String> types() {
-        return org.opensearch.common.collect.Set.of("date_range", "ip_range", "float_range", "double_range", "integer_range", "long_range");
+        return Set.of("date_range", "ip_range", "float_range", "double_range", "integer_range", "long_range");
     }
 
     @Override
     protected Set<String> wholeTypes() {
-        return org.opensearch.common.collect.Set.of("integer_range", "long_range");
+        return Set.of("integer_range", "long_range");
     }
 
     @Override
@@ -97,7 +96,7 @@ public void testExistsQueryDocValuesDisabled() throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     protected void registerParameters(ParameterChecker checker) throws IOException {
@@ -161,7 +160,7 @@ private XContentBuilder rangeFieldMapping(String type, CheckedConsumer<XContentB
     public void doTestDefaults(String type) throws Exception {
         XContentBuilder mapping = rangeFieldMapping(type, b -> {});
         DocumentMapper mapper = createDocumentMapper(mapping);
-        assertEquals(Strings.toString(mapping), mapper.mappingSource().toString());
+        assertEquals(mapping.toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(
             source(b -> b.startObject("field").field(getFromField(), getFrom(type)).field(getToField(), getTo(type)).endObject())
@@ -358,7 +357,7 @@ public void testSerializeDefaults() throws Exception {
             RangeFieldMapper mapper = (RangeFieldMapper) docMapper.root().getMapper("field");
             XContentBuilder builder = XContentFactory.jsonBuilder().startObject();
             mapper.doXContentBody(builder, true, ToXContent.EMPTY_PARAMS);
-            String got = Strings.toString(builder.endObject());
+            String got = builder.endObject().toString();
 
             // if type is date_range we check that the mapper contains the default format and locale
             // otherwise it should not contain a locale or format
diff --git a/server/src/test/java/org/opensearch/index/mapper/RangeFieldQueryStringQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/mapper/RangeFieldQueryStringQueryBuilderTests.java
index a8245627c6930..9dea7e13ac45e 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RangeFieldQueryStringQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RangeFieldQueryStringQueryBuilderTests.java
@@ -44,7 +44,6 @@
 import org.apache.lucene.search.PointRangeQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.time.DateMathParser;
@@ -72,22 +71,20 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         mapperService.merge(
             "_doc",
             new CompressedXContent(
-                Strings.toString(
-                    PutMappingRequest.simpleMapping(
-                        INTEGER_RANGE_FIELD_NAME,
-                        "type=integer_range",
-                        LONG_RANGE_FIELD_NAME,
-                        "type=long_range",
-                        FLOAT_RANGE_FIELD_NAME,
-                        "type=float_range",
-                        DOUBLE_RANGE_FIELD_NAME,
-                        "type=double_range",
-                        DATE_RANGE_FIELD_NAME,
-                        "type=date_range",
-                        IP_RANGE_FIELD_NAME,
-                        "type=ip_range"
-                    )
-                )
+                PutMappingRequest.simpleMapping(
+                    INTEGER_RANGE_FIELD_NAME,
+                    "type=integer_range",
+                    LONG_RANGE_FIELD_NAME,
+                    "type=long_range",
+                    FLOAT_RANGE_FIELD_NAME,
+                    "type=float_range",
+                    DOUBLE_RANGE_FIELD_NAME,
+                    "type=double_range",
+                    DATE_RANGE_FIELD_NAME,
+                    "type=date_range",
+                    IP_RANGE_FIELD_NAME,
+                    "type=ip_range"
+                ).toString()
             ),
             MapperService.MergeReason.MAPPING_UPDATE
         );
diff --git a/server/src/test/java/org/opensearch/index/mapper/RangeFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/RangeFieldTypeTests.java
index d4772f24cca93..668666a53cd7c 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RangeFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RangeFieldTypeTests.java
@@ -538,20 +538,14 @@ public void testFetchSourceValue() throws IOException {
 
         MappedFieldType longMapper = new RangeFieldMapper.Builder("field", RangeType.LONG, true, Version.V_EMPTY).build(context)
             .fieldType();
-        Map<String, Object> longRange = org.opensearch.common.collect.Map.of("gte", 3.14, "lt", "42.9");
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("gte", 3L, "lt", 42L)),
-            fetchSourceValue(longMapper, longRange)
-        );
+        Map<String, Object> longRange = Map.of("gte", 3.14, "lt", "42.9");
+        assertEquals(Collections.singletonList(Map.of("gte", 3L, "lt", 42L)), fetchSourceValue(longMapper, longRange));
 
         MappedFieldType dateMapper = new RangeFieldMapper.Builder("field", RangeType.DATE, true, Version.V_EMPTY).format(
             "yyyy/MM/dd||epoch_millis"
         ).build(context).fieldType();
-        Map<String, Object> dateRange = org.opensearch.common.collect.Map.of("lt", "1990/12/29", "gte", 597429487111L);
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("lt", "1990/12/29", "gte", "1988/12/06")),
-            fetchSourceValue(dateMapper, dateRange)
-        );
+        Map<String, Object> dateRange = Map.of("lt", "1990/12/29", "gte", 597429487111L);
+        assertEquals(Collections.singletonList(Map.of("lt", "1990/12/29", "gte", "1988/12/06")), fetchSourceValue(dateMapper, dateRange));
     }
 
     public void testParseSourceValueWithFormat() throws IOException {
@@ -560,23 +554,14 @@ public void testParseSourceValueWithFormat() throws IOException {
 
         MappedFieldType longMapper = new RangeFieldMapper.Builder("field", RangeType.LONG, true, Version.V_EMPTY).build(context)
             .fieldType();
-        Map<String, Object> longRange = org.opensearch.common.collect.Map.of("gte", 3.14, "lt", "42.9");
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("gte", 3L, "lt", 42L)),
-            fetchSourceValue(longMapper, longRange)
-        );
+        Map<String, Object> longRange = Map.of("gte", 3.14, "lt", "42.9");
+        assertEquals(Collections.singletonList(Map.of("gte", 3L, "lt", 42L)), fetchSourceValue(longMapper, longRange));
 
         MappedFieldType dateMapper = new RangeFieldMapper.Builder("field", RangeType.DATE, true, Version.V_EMPTY).format("strict_date_time")
             .build(context)
             .fieldType();
-        Map<String, Object> dateRange = org.opensearch.common.collect.Map.of("lt", "1990-12-29T00:00:00.000Z");
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("lt", "1990/12/29")),
-            fetchSourceValue(dateMapper, dateRange, "yyy/MM/dd")
-        );
-        assertEquals(
-            Collections.singletonList(org.opensearch.common.collect.Map.of("lt", "662428800000")),
-            fetchSourceValue(dateMapper, dateRange, "epoch_millis")
-        );
+        Map<String, Object> dateRange = Map.of("lt", "1990-12-29T00:00:00.000Z");
+        assertEquals(Collections.singletonList(Map.of("lt", "1990/12/29")), fetchSourceValue(dateMapper, dateRange, "yyy/MM/dd"));
+        assertEquals(Collections.singletonList(Map.of("lt", "662428800000")), fetchSourceValue(dateMapper, dateRange, "epoch_millis"));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/RootObjectMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/RootObjectMapperTests.java
index bb92a4d6d49cf..244053b579128 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RootObjectMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RootObjectMapperTests.java
@@ -35,11 +35,10 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
@@ -53,156 +52,166 @@ public class RootObjectMapperTests extends OpenSearchSingleNodeTestCase {
 
     public void testNumericDetection() throws Exception {
         MergeReason reason = randomFrom(MergeReason.MAPPING_UPDATE, MergeReason.INDEX_TEMPLATE);
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").field("numeric_detection", false).endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("numeric_detection", false)
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), reason);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // update with a different explicit value
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").field("numeric_detection", true).endObject().endObject()
-        );
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("numeric_detection", true)
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping2), reason);
         assertEquals(mapping2, mapper.mappingSource().toString());
 
         // update with an implicit value: no change
-        String mapping3 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping3 = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping3), reason);
         assertEquals(mapping2, mapper.mappingSource().toString());
     }
 
     public void testDateDetection() throws Exception {
         MergeReason reason = randomFrom(MergeReason.MAPPING_UPDATE, MergeReason.INDEX_TEMPLATE);
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").field("date_detection", true).endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("date_detection", true)
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), reason);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // update with a different explicit value
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").field("date_detection", false).endObject().endObject()
-        );
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("date_detection", false)
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping2), reason);
         assertEquals(mapping2, mapper.mappingSource().toString());
 
         // update with an implicit value: no change
-        String mapping3 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping3 = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping3), reason);
         assertEquals(mapping2, mapper.mappingSource().toString());
     }
 
     public void testDateFormatters() throws Exception {
         MergeReason reason = randomFrom(MergeReason.MAPPING_UPDATE, MergeReason.INDEX_TEMPLATE);
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .field("dynamic_date_formats", Arrays.asList("yyyy-MM-dd"))
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("dynamic_date_formats", Arrays.asList("yyyy-MM-dd"))
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), reason);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // no update if formatters are not set explicitly
-        String mapping2 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping2 = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping2), reason);
         assertEquals(mapping, mapper.mappingSource().toString());
 
-        String mapping3 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .field("dynamic_date_formats", Arrays.asList())
-                .endObject()
-                .endObject()
-        );
+        String mapping3 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("dynamic_date_formats", Arrays.asList())
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping3), reason);
         assertEquals(mapping3, mapper.mappingSource().toString());
     }
 
     public void testDynamicTemplates() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startArray("dynamic_templates")
-                .startObject()
-                .startObject("my_template")
-                .field("match_mapping_type", "string")
-                .startObject("mapping")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startArray("dynamic_templates")
+            .startObject()
+            .startObject("my_template")
+            .field("match_mapping_type", "string")
+            .startObject("mapping")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
         assertEquals(mapping, mapper.mappingSource().toString());
 
         // no update if templates are not set explicitly
-        String mapping2 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping2 = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping2), MergeReason.MAPPING_UPDATE);
         assertEquals(mapping, mapper.mappingSource().toString());
 
-        String mapping3 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .field("dynamic_templates", Arrays.asList())
-                .endObject()
-                .endObject()
-        );
+        String mapping3 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .field("dynamic_templates", Arrays.asList())
+            .endObject()
+            .endObject()
+            .toString();
         mapper = mapperService.merge("type", new CompressedXContent(mapping3), MergeReason.MAPPING_UPDATE);
         assertEquals(mapping3, mapper.mappingSource().toString());
     }
 
     public void testDynamicTemplatesForIndexTemplate() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startArray("dynamic_templates")
-                .startObject()
-                .startObject("first_template")
-                .field("path_match", "first")
-                .startObject("mapping")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .startObject()
-                .startObject("second_template")
-                .field("path_match", "second")
-                .startObject("mapping")
-                .field("type", "keyword")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endArray()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startArray("dynamic_templates")
+            .startObject()
+            .startObject("first_template")
+            .field("path_match", "first")
+            .startObject("mapping")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .startObject()
+            .startObject("second_template")
+            .field("path_match", "second")
+            .startObject("mapping")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endArray()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), MergeReason.INDEX_TEMPLATE);
 
         // There should be no update if templates are not set.
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "integer")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "integer")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         DocumentMapper mapper = mapperService.merge(
             MapperService.SINGLE_MAPPING_NAME,
             new CompressedXContent(mapping),
@@ -217,29 +226,28 @@ public void testDynamicTemplatesForIndexTemplate() throws IOException {
         assertEquals("second", templates[1].pathMatch());
 
         // Dynamic templates should be appended and deduplicated.
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startArray("dynamic_templates")
-                .startObject()
-                .startObject("third_template")
-                .field("path_match", "third")
-                .startObject("mapping")
-                .field("type", "integer")
-                .endObject()
-                .endObject()
-                .endObject()
-                .startObject()
-                .startObject("second_template")
-                .field("path_match", "second_updated")
-                .startObject("mapping")
-                .field("type", "double")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endArray()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startArray("dynamic_templates")
+            .startObject()
+            .startObject("third_template")
+            .field("path_match", "third")
+            .startObject("mapping")
+            .field("type", "integer")
+            .endObject()
+            .endObject()
+            .endObject()
+            .startObject()
+            .startObject("second_template")
+            .field("path_match", "second_updated")
+            .startObject("mapping")
+            .field("type", "double")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endArray()
+            .endObject()
+            .toString();
         mapper = mapperService.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping), MergeReason.INDEX_TEMPLATE);
 
         templates = mapper.root().dynamicTemplates();
@@ -253,30 +261,28 @@ public void testDynamicTemplatesForIndexTemplate() throws IOException {
     }
 
     public void testIllegalFormatField() throws Exception {
-        String dynamicMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startArray("dynamic_date_formats")
-                .startArray()
-                .value("test_format")
-                .endArray()
-                .endArray()
-                .endObject()
-                .endObject()
-        );
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startArray("date_formats")
-                .startArray()
-                .value("test_format")
-                .endArray()
-                .endArray()
-                .endObject()
-                .endObject()
-        );
+        String dynamicMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startArray("dynamic_date_formats")
+            .startArray()
+            .value("test_format")
+            .endArray()
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startArray("date_formats")
+            .startArray()
+            .value("test_format")
+            .endArray()
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         for (String m : Arrays.asList(mapping, dynamicMapping)) {
@@ -289,15 +295,14 @@ public void testIllegalFormatField() throws Exception {
     }
 
     public void testIllegalDynamicTemplates() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("dynamic_templates")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("dynamic_templates")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         MapperParsingException e = expectThrows(MapperParsingException.class, () -> parser.parse("type", new CompressedXContent(mapping)));
@@ -325,7 +330,7 @@ public void testIllegalDynamicTemplateUnknownFieldType() throws Exception {
         }
         mapping.endObject();
         MapperService mapperService = createIndex("test").mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(Strings.toString(mapping)), MergeReason.MAPPING_UPDATE);
+        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
         assertThat(mapper.mappingSource().toString(), containsString("\"type\":\"string\""));
         assertWarnings(
             "dynamic template [my_template1] has invalid content [{\"match_mapping_type\":\"string\",\"mapping\":{\"type\":"
@@ -355,7 +360,7 @@ public void testIllegalDynamicTemplateUnknownAttribute() throws Exception {
         }
         mapping.endObject();
         MapperService mapperService = createIndex("test").mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(Strings.toString(mapping)), MergeReason.MAPPING_UPDATE);
+        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
         assertThat(mapper.mappingSource().toString(), containsString("\"foo\":\"bar\""));
         assertWarnings(
             "dynamic template [my_template2] has invalid content [{\"match_mapping_type\":\"string\",\"mapping\":{"
@@ -386,7 +391,7 @@ public void testIllegalDynamicTemplateInvalidAttribute() throws Exception {
         }
         mapping.endObject();
         MapperService mapperService = createIndex("test").mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(Strings.toString(mapping)), MergeReason.MAPPING_UPDATE);
+        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
         assertThat(mapper.mappingSource().toString(), containsString("\"analyzer\":\"foobar\""));
         assertWarnings(
             "dynamic template [my_template3] has invalid content [{\"match_mapping_type\":\"string\",\"mapping\":{"
@@ -423,11 +428,7 @@ public void testIllegalDynamicTemplateNoMappingType() throws Exception {
             }
             mapping.endObject();
             mapperService = createIndex("test").mapperService();
-            DocumentMapper mapper = mapperService.merge(
-                "type",
-                new CompressedXContent(Strings.toString(mapping)),
-                MergeReason.MAPPING_UPDATE
-            );
+            DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
             assertThat(mapper.mappingSource().toString(), containsString("\"index_phrases\":true"));
         }
         {
@@ -457,11 +458,7 @@ public void testIllegalDynamicTemplateNoMappingType() throws Exception {
             }
             mapping.endObject();
 
-            DocumentMapper mapper = mapperService.merge(
-                "type",
-                new CompressedXContent(Strings.toString(mapping)),
-                MergeReason.MAPPING_UPDATE
-            );
+            DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
             assertThat(mapper.mappingSource().toString(), containsString("\"foo\":\"bar\""));
             if (useMatchMappingType) {
                 assertWarnings(
@@ -507,7 +504,7 @@ public void testIllegalDynamicTemplatePre7Dot7Index() throws Exception {
         Version createdVersion = randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_6_0);
         Settings indexSettings = Settings.builder().put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), createdVersion).build();
         MapperService mapperService = createIndex("test", indexSettings).mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(Strings.toString(mapping)), MergeReason.MAPPING_UPDATE);
+        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping.toString()), MergeReason.MAPPING_UPDATE);
         assertThat(mapper.mappingSource().toString(), containsString("\"type\":\"string\""));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/RoutingFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/RoutingFieldMapperTests.java
index 92236ad34013b..561a35efc6d18 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RoutingFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RoutingFieldMapperTests.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.index.mapper;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import static org.hamcrest.Matchers.containsString;
@@ -45,7 +44,7 @@
 public class RoutingFieldMapperTests extends OpenSearchSingleNodeTestCase {
 
     public void testRoutingMapper() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -55,7 +54,7 @@ public void testRoutingMapper() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject()),
-                XContentType.JSON,
+                MediaTypeRegistry.JSON,
                 "routing_value"
             )
         );
@@ -65,7 +64,7 @@ public void testRoutingMapper() throws Exception {
     }
 
     public void testIncludeInObjectNotAllowed() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper docMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
@@ -76,7 +75,7 @@ public void testIncludeInObjectNotAllowed() throws Exception {
                     "test",
                     "1",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("_routing", "foo").endObject()),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
             fail("Expected failure to parse metadata field");
diff --git a/server/src/test/java/org/opensearch/index/mapper/RoutingFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/RoutingFieldTypeTests.java
index 8d3a8ea43f264..7553a6c621f62 100644
--- a/server/src/test/java/org/opensearch/index/mapper/RoutingFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/RoutingFieldTypeTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.RegexpQuery;
@@ -45,7 +46,7 @@ public void testPrefixQuery() {
         MappedFieldType ft = RoutingFieldMapper.RoutingFieldType.INSTANCE;
 
         Query expected = new PrefixQuery(new Term("_routing", new BytesRef("foo*")));
-        assertEquals(expected, ft.prefixQuery("foo*", null, MOCK_QSC));
+        assertEquals(expected, ft.prefixQuery("foo*", MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(OpenSearchException.class, () -> ft.prefixQuery("foo*", null, MOCK_QSC_DISALLOW_EXPENSIVE));
         assertEquals(
@@ -59,7 +60,7 @@ public void testRegexpQuery() {
         MappedFieldType ft = RoutingFieldMapper.RoutingFieldType.INSTANCE;
 
         Query expected = new RegexpQuery(new Term("_routing", new BytesRef("foo?")));
-        assertEquals(expected, ft.regexpQuery("foo?", 0, 0, 10, null, MOCK_QSC));
+        assertEquals(expected, ft.regexpQuery("foo?", 0, 0, 10, MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(
             OpenSearchException.class,
@@ -72,7 +73,7 @@ public void testWildcardQuery() {
         MappedFieldType ft = RoutingFieldMapper.RoutingFieldType.INSTANCE;
 
         Query expected = new WildcardQuery(new Term("_routing", new BytesRef("foo*")));
-        assertEquals(expected, ft.wildcardQuery("foo*", null, MOCK_QSC));
+        assertEquals(expected, ft.wildcardQuery("foo*", MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC));
 
         OpenSearchException ee = expectThrows(
             OpenSearchException.class,
diff --git a/server/src/test/java/org/opensearch/index/mapper/SourceFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/SourceFieldMapperTests.java
index 3cb16b452cbf4..83d42fd423f08 100644
--- a/server/src/test/java/org/opensearch/index/mapper/SourceFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/SourceFieldMapperTests.java
@@ -33,18 +33,17 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.index.IndexableField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.Collection;
 import java.util.Map;
@@ -60,9 +59,14 @@ protected Collection<Class<? extends Plugin>> getPlugins() {
     }
 
     public void testNoFormat() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("type").startObject("_source").endObject().endObject().endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         DocumentMapper documentMapper = parser.parse("type", new CompressedXContent(mapping));
@@ -71,11 +75,11 @@ public void testNoFormat() throws Exception {
                 "test",
                 "1",
                 BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", "value").endObject()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
-        assertThat(XContentFactory.xContentType(doc.source().toBytesRef().bytes), equalTo(XContentType.JSON));
+        assertThat(MediaTypeRegistry.xContent(doc.source().toBytesRef().bytes), equalTo(MediaTypeRegistry.JSON));
 
         documentMapper = parser.parse("type", new CompressedXContent(mapping));
         doc = documentMapper.parse(
@@ -87,20 +91,19 @@ public void testNoFormat() throws Exception {
             )
         );
 
-        assertThat(XContentHelper.xContentType(doc.source()), equalTo(XContentType.SMILE));
+        assertThat(MediaTypeRegistry.xContentType(doc.source()), equalTo(XContentType.SMILE));
     }
 
     public void testIncludes() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("includes", new String[] { "path1*" })
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("includes", new String[] { "path1*" })
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper documentMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -121,7 +124,7 @@ public void testIncludes() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -135,16 +138,15 @@ public void testIncludes() throws Exception {
     }
 
     public void testExcludes() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("excludes", "path1*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("excludes", "path1*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper documentMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -165,7 +167,7 @@ public void testExcludes() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -181,59 +183,55 @@ public void testExcludes() throws Exception {
     public void testEnabledNotUpdateable() throws Exception {
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
         // using default of true
-        String mapping1 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping1 = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(mapping1, mapping2, parser, "Cannot update parameter [enabled] from [true] to [false]");
 
         // not changing is ok
-        String mapping3 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .field("enabled", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping3 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .field("enabled", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(mapping1, mapping3, parser);
     }
 
     public void testIncludesNotUpdateable() throws Exception {
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
-        String defaultMapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
-        String mapping1 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("includes", "foo.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String defaultMapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
+        String mapping1 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("includes", "foo.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(defaultMapping, mapping1, parser, "Cannot update parameter [includes] from [[]] to [[foo.*]]");
         assertConflicts(mapping1, defaultMapping, parser, "Cannot update parameter [includes] from [[foo.*]] to [[]]");
 
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("includes", "foo.*", "bar.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("includes", "foo.*", "bar.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(mapping1, mapping2, parser, "Cannot update parameter [includes] from [[foo.*]] to [[foo.*, bar.*]]");
 
         // not changing is ok
@@ -242,30 +240,28 @@ public void testIncludesNotUpdateable() throws Exception {
 
     public void testExcludesNotUpdateable() throws Exception {
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
-        String defaultMapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
-        String mapping1 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("excludes", "foo.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String defaultMapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
+        String mapping1 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("excludes", "foo.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(defaultMapping, mapping1, parser, "Cannot update parameter [excludes] from [[]] to [[foo.*]]");
         assertConflicts(mapping1, defaultMapping, parser, "Cannot update parameter [excludes] from [[foo.*]] to [[]]");
 
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("excludes", "foo.*", "bar.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("excludes", "foo.*", "bar.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertConflicts(mapping1, mapping2, parser, "Cannot update parameter [excludes]");
 
         // not changing is ok
@@ -274,55 +270,52 @@ public void testExcludesNotUpdateable() throws Exception {
 
     public void testComplete() throws Exception {
         DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         assertTrue(parser.parse("type", new CompressedXContent(mapping)).sourceMapper().isComplete());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .field("enabled", false)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .field("enabled", false)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertFalse(parser.parse("type", new CompressedXContent(mapping)).sourceMapper().isComplete());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("includes", "foo.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("includes", "foo.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertFalse(parser.parse("type", new CompressedXContent(mapping)).sourceMapper().isComplete());
 
-        mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("_source")
-                .array("excludes", "foo.*")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("_source")
+            .array("excludes", "foo.*")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         assertFalse(parser.parse("type", new CompressedXContent(mapping)).sourceMapper().isComplete());
     }
 
     public void testSourceObjectContainsExtraTokens() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().toString();
         DocumentMapper documentMapper = createIndex("test").mapperService()
             .documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
 
         try {
-            documentMapper.parse(new SourceToParse("test", "1", new BytesArray("{}}"), XContentType.JSON)); // extra end object
-                                                                                                            // (invalid JSON)
+            documentMapper.parse(new SourceToParse("test", "1", new BytesArray("{}}"), MediaTypeRegistry.JSON)); // extra end object
+            // (invalid JSON)
             fail("Expected parse exception");
         } catch (MapperParsingException e) {
             assertNotNull(e.getRootCause());
diff --git a/server/src/test/java/org/opensearch/index/mapper/StoredNumericValuesTests.java b/server/src/test/java/org/opensearch/index/mapper/StoredNumericValuesTests.java
index b6e1818364328..cebd92a280556 100644
--- a/server/src/test/java/org/opensearch/index/mapper/StoredNumericValuesTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/StoredNumericValuesTests.java
@@ -37,17 +37,17 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.store.ByteBuffersDirectory;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.util.set.Sets;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.fieldvisitor.CustomFieldsVisitor;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
+import java.math.BigInteger;
 import java.util.Set;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -56,55 +56,58 @@ public class StoredNumericValuesTests extends OpenSearchSingleNodeTestCase {
     public void testBytesAndNumericRepresentation() throws Exception {
         IndexWriter writer = new IndexWriter(new ByteBuffersDirectory(), new IndexWriterConfig(Lucene.STANDARD_ANALYZER));
 
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "byte")
-                .field("store", true)
-                .endObject()
-                .startObject("field2")
-                .field("type", "short")
-                .field("store", true)
-                .endObject()
-                .startObject("field3")
-                .field("type", "integer")
-                .field("store", true)
-                .endObject()
-                .startObject("field4")
-                .field("type", "float")
-                .field("store", true)
-                .endObject()
-                .startObject("field5")
-                .field("type", "long")
-                .field("store", true)
-                .endObject()
-                .startObject("field6")
-                .field("type", "double")
-                .field("store", true)
-                .endObject()
-                .startObject("field7")
-                .field("type", "ip")
-                .field("store", true)
-                .endObject()
-                .startObject("field8")
-                .field("type", "ip")
-                .field("store", true)
-                .endObject()
-                .startObject("field9")
-                .field("type", "date")
-                .field("store", true)
-                .endObject()
-                .startObject("field10")
-                .field("type", "boolean")
-                .field("store", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "byte")
+            .field("store", true)
+            .endObject()
+            .startObject("field2")
+            .field("type", "short")
+            .field("store", true)
+            .endObject()
+            .startObject("field3")
+            .field("type", "integer")
+            .field("store", true)
+            .endObject()
+            .startObject("field4")
+            .field("type", "float")
+            .field("store", true)
+            .endObject()
+            .startObject("field5")
+            .field("type", "long")
+            .field("store", true)
+            .endObject()
+            .startObject("field6")
+            .field("type", "double")
+            .field("store", true)
+            .endObject()
+            .startObject("field7")
+            .field("type", "ip")
+            .field("store", true)
+            .endObject()
+            .startObject("field8")
+            .field("type", "ip")
+            .field("store", true)
+            .endObject()
+            .startObject("field9")
+            .field("type", "date")
+            .field("store", true)
+            .endObject()
+            .startObject("field10")
+            .field("type", "boolean")
+            .field("store", true)
+            .endObject()
+            .startObject("field11")
+            .field("type", "unsigned_long")
+            .field("store", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper mapper = mapperService.merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
 
@@ -129,9 +132,10 @@ public void testBytesAndNumericRepresentation() throws Exception {
                         .field("field8", "2001:db8::2:1")
                         .field("field9", "2016-04-05")
                         .field("field10", true)
+                        .field("field11", "1")
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
 
@@ -150,13 +154,14 @@ public void testBytesAndNumericRepresentation() throws Exception {
             "field7",
             "field8",
             "field9",
-            "field10"
+            "field10",
+            "field11"
         );
         CustomFieldsVisitor fieldsVisitor = new CustomFieldsVisitor(fieldNames, false);
         searcher.doc(0, fieldsVisitor);
 
         fieldsVisitor.postProcess(mapperService::fieldType);
-        assertThat(fieldsVisitor.fields().size(), equalTo(10));
+        assertThat(fieldsVisitor.fields().size(), equalTo(11));
         assertThat(fieldsVisitor.fields().get("field1").size(), equalTo(1));
         assertThat(fieldsVisitor.fields().get("field1").get(0), equalTo((byte) 1));
 
@@ -189,6 +194,9 @@ public void testBytesAndNumericRepresentation() throws Exception {
         assertThat(fieldsVisitor.fields().get("field10").size(), equalTo(1));
         assertThat(fieldsVisitor.fields().get("field10").get(0), equalTo(true));
 
+        assertThat(fieldsVisitor.fields().get("field11").size(), equalTo(1));
+        assertThat(fieldsVisitor.fields().get("field11").get(0), equalTo(BigInteger.valueOf(1)));
+
         reader.close();
         writer.close();
     }
diff --git a/server/src/test/java/org/opensearch/index/mapper/TextFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/TextFieldMapperTests.java
index 8a5a0e8864d3e..a9b902e121bda 100644
--- a/server/src/test/java/org/opensearch/index/mapper/TextFieldMapperTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/TextFieldMapperTests.java
@@ -33,10 +33,7 @@
 package org.opensearch.index.mapper;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.CannedTokenStream;
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.analysis.StopFilter;
-import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.core.KeywordAnalyzer;
 import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
@@ -62,12 +59,15 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.tests.analysis.CannedTokenStream;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
+import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.CharFilterFactory;
@@ -102,7 +102,7 @@ protected void writeFieldValue(XContentBuilder builder) throws IOException {
 
     @Override
     protected void assertParseMaximalWarnings() {
-        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 8.0");
+        assertWarnings("Parameter [boost] on field [field] is deprecated and will be removed in 3.0");
     }
 
     public final void testExistsQueryIndexDisabled() throws IOException {
@@ -229,20 +229,9 @@ public TokenStream create(TokenStream tokenStream) {
             )
         );
         return new IndexAnalyzers(
-            org.opensearch.common.collect.Map.of(
-                "default",
-                dflt,
-                "standard",
-                standard,
-                "keyword",
-                keyword,
-                "whitespace",
-                whitespace,
-                "my_stop_analyzer",
-                stop
-            ),
-            org.opensearch.common.collect.Map.of(),
-            org.opensearch.common.collect.Map.of()
+            Map.of("default", dflt, "standard", standard, "keyword", keyword, "whitespace", whitespace, "my_stop_analyzer", stop),
+            Map.of(),
+            Map.of()
         );
     }
 
@@ -253,7 +242,7 @@ protected void minimalMapping(XContentBuilder b) throws IOException {
 
     public void testDefaults() throws IOException {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
-        assertEquals(Strings.toString(fieldMapping(this::minimalMapping)), mapper.mappingSource().toString());
+        assertEquals(fieldMapping(this::minimalMapping).toString(), mapper.mappingSource().toString());
 
         ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
         IndexableField[] fields = doc.rootDoc().getFields("field");
@@ -280,11 +269,45 @@ public void testBWCSerialization() throws IOException {
                 b.startObject("subfield").field("type", "long").endObject();
             }
             b.endObject();
+            b.field("store", true);
+            b.field("similarity", "BM25");
+            b.field("index_options", "offsets");
+            b.field("norms", false);
+            b.field("term_vector", "yes");
+            b.field("position_increment_gap", 0);
+            b.startObject("fielddata_frequency_filter");
+            {
+                b.field("min", 0.001);
+                b.field("max", 0.1);
+                b.field("min_segment_size", 500);
+            }
+            b.endObject();
+            b.field("eager_global_ordinals", true);
+            b.field("index_phrases", true);
+            b.startObject("index_prefixes");
+            {
+                b.field("min_chars", 1);
+                b.field("max_chars", 10);
+            }
+            b.endObject();
+            b.startObject("meta");
+            {
+                b.field("unit", "min");
+            }
+            b.endObject();
+            b.startArray("copy_to");
+            {
+                b.value("target");
+            }
+            b.endArray();
         }));
-
         assertEquals(
-            "{\"_doc\":{\"properties\":{\"field\":{\"type\":\"text\",\"fields\":{\"subfield\":{\"type\":\"long\"}},\"fielddata\":true}}}}",
-            Strings.toString(mapperService.documentMapper())
+            "{\"_doc\":{\"properties\":{\"field\":{\"type\":\"text\",\"store\":true,\"fields\":{\"subfield\":{\"type\":\"long\"}},"
+                + "\"copy_to\":[\"target\"],\"meta\":{\"unit\":\"min\"},\"index_options\":\"offsets\",\"term_vector\":\"yes\",\"norms\":false,"
+                + "\"similarity\":\"BM25\",\"eager_global_ordinals\":true,\"position_increment_gap\":0,"
+                + "\"fielddata\":true,\"fielddata_frequency_filter\":{\"min\":0.001,\"max\":0.1,\"min_segment_size\":500},"
+                + "\"index_prefixes\":{\"min_chars\":1,\"max_chars\":10},\"index_phrases\":true}}}}",
+            Strings.toString(MediaTypeRegistry.JSON, mapperService.documentMapper())
         );
     }
 
@@ -318,14 +341,14 @@ public void testIndexOptions() throws IOException {
         supportedOptions.put("positions", IndexOptions.DOCS_AND_FREQS_AND_POSITIONS);
         supportedOptions.put("offsets", IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS);
 
-        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("_doc").startObject("properties");
+        XContentBuilder mapping = MediaTypeRegistry.JSON.contentBuilder().startObject().startObject("_doc").startObject("properties");
         for (String option : supportedOptions.keySet()) {
             mapping.startObject(option).field("type", "text").field("index_options", option).endObject();
         }
         mapping.endObject().endObject().endObject();
 
         DocumentMapper mapper = createDocumentMapper(mapping);
-        String serialized = Strings.toString(mapper);
+        String serialized = Strings.toString(MediaTypeRegistry.JSON, mapper);
         assertThat(serialized, containsString("\"offsets\":{\"type\":\"text\",\"index_options\":\"offsets\"}"));
         assertThat(serialized, containsString("\"freqs\":{\"type\":\"text\",\"index_options\":\"freqs\"}"));
         assertThat(serialized, containsString("\"docs\":{\"type\":\"text\",\"index_options\":\"docs\"}"));
@@ -388,24 +411,24 @@ public void testSearchAnalyzerSerialization() throws IOException {
         XContentBuilder mapping = fieldMapping(
             b -> b.field("type", "text").field("analyzer", "standard").field("search_analyzer", "keyword")
         );
-        assertEquals(Strings.toString(mapping), createDocumentMapper(mapping).mappingSource().toString());
+        assertEquals(mapping.toString(), createDocumentMapper(mapping).mappingSource().toString());
 
         // special case: default index analyzer
         mapping = fieldMapping(b -> b.field("type", "text").field("analyzer", "default").field("search_analyzer", "keyword"));
-        assertEquals(Strings.toString(mapping), createDocumentMapper(mapping).mappingSource().toString());
+        assertEquals(mapping.toString(), createDocumentMapper(mapping).mappingSource().toString());
 
         // special case: default search analyzer
         mapping = fieldMapping(b -> b.field("type", "text").field("analyzer", "keyword").field("search_analyzer", "default"));
-        assertEquals(Strings.toString(mapping), createDocumentMapper(mapping).mappingSource().toString());
+        assertEquals(mapping.toString(), createDocumentMapper(mapping).mappingSource().toString());
 
-        XContentBuilder builder = XContentFactory.jsonBuilder();
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
         builder.startObject();
         createDocumentMapper(fieldMapping(this::minimalMapping)).toXContent(
             builder,
             new ToXContent.MapParams(Collections.singletonMap("include_defaults", "true"))
         );
         builder.endObject();
-        String mappingString = Strings.toString(builder);
+        String mappingString = builder.toString();
         assertTrue(mappingString.contains("analyzer"));
         assertTrue(mappingString.contains("search_analyzer"));
         assertTrue(mappingString.contains("search_quote_analyzer"));
@@ -418,7 +441,7 @@ public void testSearchQuoteAnalyzerSerialization() throws IOException {
                 .field("search_analyzer", "standard")
                 .field("search_quote_analyzer", "keyword")
         );
-        assertEquals(Strings.toString(mapping), createDocumentMapper(mapping).mappingSource().toString());
+        assertEquals(mapping.toString(), createDocumentMapper(mapping).mappingSource().toString());
 
         // special case: default index/search analyzer
         mapping = fieldMapping(
@@ -427,7 +450,7 @@ public void testSearchQuoteAnalyzerSerialization() throws IOException {
                 .field("search_analyzer", "default")
                 .field("search_quote_analyzer", "keyword")
         );
-        assertEquals(Strings.toString(mapping), createDocumentMapper(mapping).mappingSource().toString());
+        assertEquals(mapping.toString(), createDocumentMapper(mapping).mappingSource().toString());
     }
 
     public void testTermVectors() throws IOException {
@@ -511,10 +534,9 @@ public void testEagerGlobalOrdinals() throws IOException {
 
     public void testFielddata() throws IOException {
         MapperService disabledMapper = createMapperService(fieldMapping(this::minimalMapping));
-        Exception e = expectThrows(
-            IllegalArgumentException.class,
-            () -> disabledMapper.fieldType("field").fielddataBuilder("test", () -> { throw new UnsupportedOperationException(); })
-        );
+        Exception e = expectThrows(IllegalArgumentException.class, () -> disabledMapper.fieldType("field").fielddataBuilder("test", () -> {
+            throw new UnsupportedOperationException();
+        }));
         assertThat(e.getMessage(), containsString("Text fields are not optimised for operations that require per-document field data"));
 
         MapperService enabledMapper = createMapperService(fieldMapping(b -> b.field("type", "text").field("fielddata", true)));
diff --git a/server/src/test/java/org/opensearch/index/mapper/TextFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/TextFieldTypeTests.java
index 18b04c1be5668..0592a972db5e9 100644
--- a/server/src/test/java/org/opensearch/index/mapper/TextFieldTypeTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/TextFieldTypeTests.java
@@ -60,8 +60,9 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.apache.lucene.search.MultiTermQuery.CONSTANT_SCORE_REWRITE;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.lucene.search.MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE;
+import static org.apache.lucene.search.MultiTermQuery.CONSTANT_SCORE_REWRITE;
 
 public class TextFieldTypeTests extends FieldTypeTestCase {
 
@@ -120,7 +121,10 @@ public void testRangeQuery() {
 
     public void testRegexpQuery() {
         MappedFieldType ft = createFieldType();
-        assertEquals(new RegexpQuery(new Term("field", "foo.*")), ft.regexpQuery("foo.*", 0, 0, 10, null, MOCK_QSC));
+        assertEquals(
+            new RegexpQuery(new Term("field", "foo.*")),
+            ft.regexpQuery("foo.*", 0, 0, 10, CONSTANT_SCORE_BLENDED_REWRITE, MOCK_QSC)
+        );
 
         MappedFieldType unsearchable = new TextFieldType("field", false, false, Collections.emptyMap());
         IllegalArgumentException e = expectThrows(
@@ -165,7 +169,7 @@ public void testIndexPrefixes() {
         assertEquals(new ConstantScoreQuery(new TermQuery(new Term("field._index_prefix", "goin"))), q);
 
         q = ft.prefixQuery("internationalisatio", CONSTANT_SCORE_REWRITE, false, MOCK_QSC);
-        assertEquals(new PrefixQuery(new Term("field", "internationalisatio")), q);
+        assertEquals(new PrefixQuery(new Term("field", "internationalisatio"), CONSTANT_SCORE_REWRITE), q);
 
         q = ft.prefixQuery("Internationalisatio", CONSTANT_SCORE_REWRITE, true, MOCK_QSC);
         assertEquals(AutomatonQueries.caseInsensitivePrefixQuery(new Term("field", "Internationalisatio")), q);
@@ -184,9 +188,34 @@ public void testIndexPrefixes() {
         Automaton automaton = Operations.concatenate(Arrays.asList(Automata.makeChar('g'), Automata.makeAnyChar()));
 
         Query expected = new ConstantScoreQuery(
-            new BooleanQuery.Builder().add(new AutomatonQuery(new Term("field._index_prefix", "g*"), automaton), BooleanClause.Occur.SHOULD)
-                .add(new TermQuery(new Term("field", "g")), BooleanClause.Occur.SHOULD)
-                .build()
+            new BooleanQuery.Builder().add(
+                new AutomatonQuery(
+                    new Term("field._index_prefix", "g*"),
+                    automaton,
+                    Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+                    false,
+                    CONSTANT_SCORE_REWRITE
+                ),
+                BooleanClause.Occur.SHOULD
+            ).add(new TermQuery(new Term("field", "g")), BooleanClause.Occur.SHOULD).build()
+        );
+
+        assertThat(q, equalTo(expected));
+
+        q = ft.prefixQuery("g", null, false, randomMockShardContext());
+        automaton = Operations.concatenate(Arrays.asList(Automata.makeChar('g'), Automata.makeAnyChar()));
+
+        expected = new ConstantScoreQuery(
+            new BooleanQuery.Builder().add(
+                new AutomatonQuery(
+                    new Term("field._index_prefix", "g*"),
+                    automaton,
+                    Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+                    false,
+                    CONSTANT_SCORE_REWRITE
+                ),
+                BooleanClause.Occur.SHOULD
+            ).add(new TermQuery(new Term("field", "g")), BooleanClause.Occur.SHOULD).build()
         );
 
         assertThat(q, equalTo(expected));
@@ -196,18 +225,18 @@ public void testFetchSourceValue() throws IOException {
         TextFieldType fieldType = createFieldType();
         fieldType.setIndexAnalyzer(Lucene.STANDARD_ANALYZER);
 
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(fieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(fieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(fieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(fieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(fieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(fieldType, true));
 
         TextFieldMapper.PrefixFieldType prefixFieldType = new TextFieldMapper.PrefixFieldType(fieldType, "field._index_prefix", 2, 10);
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(prefixFieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(prefixFieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(prefixFieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(prefixFieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(prefixFieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(prefixFieldType, true));
 
         TextFieldMapper.PhraseFieldType phraseFieldType = new TextFieldMapper.PhraseFieldType(fieldType);
-        assertEquals(org.opensearch.common.collect.List.of("value"), fetchSourceValue(phraseFieldType, "value"));
-        assertEquals(org.opensearch.common.collect.List.of("42"), fetchSourceValue(phraseFieldType, 42L));
-        assertEquals(org.opensearch.common.collect.List.of("true"), fetchSourceValue(phraseFieldType, true));
+        assertEquals(List.of("value"), fetchSourceValue(phraseFieldType, "value"));
+        assertEquals(List.of("42"), fetchSourceValue(phraseFieldType, 42L));
+        assertEquals(List.of("true"), fetchSourceValue(phraseFieldType, true));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/mapper/TypeFieldMapperTests.java b/server/src/test/java/org/opensearch/index/mapper/TypeFieldMapperTests.java
deleted file mode 100644
index 89eee655ca9d4..0000000000000
--- a/server/src/test/java/org/opensearch/index/mapper/TypeFieldMapperTests.java
+++ /dev/null
@@ -1,106 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.mapper;
-
-import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.IndexWriter;
-import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.index.SortedSetDocValues;
-import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.IndexService;
-import org.opensearch.index.fielddata.IndexFieldDataCache;
-import org.opensearch.index.fielddata.IndexOrdinalsFieldData;
-import org.opensearch.index.fielddata.LeafOrdinalsFieldData;
-import org.opensearch.index.mapper.MapperService.MergeReason;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
-import org.opensearch.test.InternalSettingsPlugin;
-
-import java.io.IOException;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.function.Function;
-
-public class TypeFieldMapperTests extends OpenSearchSingleNodeTestCase {
-
-    @Override
-    protected Collection<Class<? extends Plugin>> getPlugins() {
-        return pluginList(InternalSettingsPlugin.class);
-    }
-
-    public void testDocValuesSingleType() throws Exception {
-        testDocValues(this::createIndex);
-        assertWarnings("[types removal] Using the _type field in queries and aggregations is deprecated, prefer to use a field instead.");
-    }
-
-    public static void testDocValues(Function<String, IndexService> createIndex) throws IOException {
-        MapperService mapperService = createIndex.apply("test").mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent("{\"type\":{}}"), MergeReason.MAPPING_UPDATE);
-        ParsedDocument document = mapper.parse(new SourceToParse("index", "id", new BytesArray("{}"), XContentType.JSON));
-
-        Directory dir = newDirectory();
-        IndexWriter w = new IndexWriter(dir, newIndexWriterConfig());
-        w.addDocument(document.rootDoc());
-        DirectoryReader r = DirectoryReader.open(w);
-        w.close();
-
-        MappedFieldType ft = mapperService.fieldType(TypeFieldMapper.NAME);
-        IndexOrdinalsFieldData fd = (IndexOrdinalsFieldData) ft.fielddataBuilder(
-            "test",
-            () -> { throw new UnsupportedOperationException(); }
-        ).build(new IndexFieldDataCache.None(), new NoneCircuitBreakerService());
-        LeafOrdinalsFieldData afd = fd.load(r.leaves().get(0));
-        SortedSetDocValues values = afd.getOrdinalsValues();
-        assertTrue(values.advanceExact(0));
-        assertEquals(0, values.nextOrd());
-        assertEquals(SortedSetDocValues.NO_MORE_ORDS, values.nextOrd());
-        assertEquals(new BytesRef("type"), values.lookupOrd(0));
-        r.close();
-        dir.close();
-    }
-
-    public void testDefaults() throws IOException {
-        Settings indexSettings = Settings.EMPTY;
-        MapperService mapperService = createIndex("test", indexSettings).mapperService();
-        DocumentMapper mapper = mapperService.merge("type", new CompressedXContent("{\"type\":{}}"), MergeReason.MAPPING_UPDATE);
-        ParsedDocument document = mapper.parse(new SourceToParse("index", "id", new BytesArray("{}"), XContentType.JSON));
-        assertEquals(Collections.<IndexableField>emptyList(), Arrays.asList(document.rootDoc().getFields(TypeFieldMapper.NAME)));
-    }
-}
diff --git a/server/src/test/java/org/opensearch/index/mapper/TypeFieldTypeTests.java b/server/src/test/java/org/opensearch/index/mapper/TypeFieldTypeTests.java
deleted file mode 100644
index 66377a16b90d4..0000000000000
--- a/server/src/test/java/org/opensearch/index/mapper/TypeFieldTypeTests.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.mapper;
-
-import org.apache.lucene.search.MatchAllDocsQuery;
-import org.apache.lucene.search.MatchNoDocsQuery;
-import org.apache.lucene.search.Query;
-import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.Mockito;
-
-import java.util.Arrays;
-
-public class TypeFieldTypeTests extends OpenSearchTestCase {
-
-    public void testTermsQuery() {
-        QueryShardContext context = Mockito.mock(QueryShardContext.class);
-
-        TypeFieldMapper.TypeFieldType ft = new TypeFieldMapper.TypeFieldType("_doc");
-        Query query = ft.termQuery("my_type", context);
-        assertEquals(new MatchNoDocsQuery(), query);
-
-        query = ft.termQuery("_doc", context);
-        assertEquals(new MatchAllDocsQuery(), query);
-
-        query = ft.termsQuery(Arrays.asList("_doc", "type", "foo"), context);
-        assertEquals(new MatchAllDocsQuery(), query);
-
-        query = ft.termsQuery(Arrays.asList("type", "foo"), context);
-        assertEquals(new MatchNoDocsQuery(), query);
-
-        query = ft.termQueryCaseInsensitive("_DOC", context);
-        assertEquals(new MatchAllDocsQuery(), query);
-
-        assertWarnings("[types removal] Using the _type field in queries and aggregations is deprecated, prefer to use a field instead.");
-    }
-}
diff --git a/server/src/test/java/org/opensearch/index/mapper/TypeParsersTests.java b/server/src/test/java/org/opensearch/index/mapper/TypeParsersTests.java
index 2254e2eceaee9..5187242f5fdac 100644
--- a/server/src/test/java/org/opensearch/index/mapper/TypeParsersTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/TypeParsersTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.index.mapper;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -47,8 +47,8 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.stream.IntStream;
 import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 
 import static org.opensearch.index.analysis.AnalysisRegistry.DEFAULT_ANALYZER_NAME;
 import static org.opensearch.index.analysis.AnalysisRegistry.DEFAULT_SEARCH_ANALYZER_NAME;
diff --git a/server/src/test/java/org/opensearch/index/mapper/UidTests.java b/server/src/test/java/org/opensearch/index/mapper/UidTests.java
index a7253d9a6a7c4..9ce737358e252 100644
--- a/server/src/test/java/org/opensearch/index/mapper/UidTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/UidTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index.mapper;
 
-import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
diff --git a/server/src/test/java/org/opensearch/index/mapper/UpdateMappingTests.java b/server/src/test/java/org/opensearch/index/mapper/UpdateMappingTests.java
index 0349307ad20ea..7e40354eb7f29 100644
--- a/server/src/test/java/org/opensearch/index/mapper/UpdateMappingTests.java
+++ b/server/src/test/java/org/opensearch/index/mapper/UpdateMappingTests.java
@@ -34,17 +34,16 @@
 
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperService.MergeReason;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -128,7 +127,7 @@ public void testConflictSameType() throws Exception {
             IllegalArgumentException.class,
             () -> mapperService.merge(
                 MapperService.SINGLE_MAPPING_NAME,
-                new CompressedXContent(Strings.toString(update)),
+                new CompressedXContent(update.toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             )
         );
@@ -138,7 +137,7 @@ public void testConflictSameType() throws Exception {
             IllegalArgumentException.class,
             () -> mapperService.merge(
                 MapperService.SINGLE_MAPPING_NAME,
-                new CompressedXContent(Strings.toString(update)),
+                new CompressedXContent(update.toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             )
         );
@@ -175,7 +174,7 @@ public void testConflictNewType() throws Exception {
             IllegalArgumentException.class,
             () -> mapperService.merge(
                 MapperService.SINGLE_MAPPING_NAME,
-                new CompressedXContent(Strings.toString(update)),
+                new CompressedXContent(update.toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             )
         );
@@ -202,7 +201,7 @@ public void testReuseMetaField() throws IOException {
             MapperParsingException.class,
             () -> mapperService.merge(
                 MapperService.SINGLE_MAPPING_NAME,
-                new CompressedXContent(Strings.toString(mapping)),
+                new CompressedXContent(mapping.toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             )
         );
@@ -212,7 +211,7 @@ public void testReuseMetaField() throws IOException {
             MapperParsingException.class,
             () -> mapperService.merge(
                 MapperService.SINGLE_MAPPING_NAME,
-                new CompressedXContent(Strings.toString(mapping)),
+                new CompressedXContent(mapping.toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             )
         );
@@ -220,26 +219,24 @@ public void testReuseMetaField() throws IOException {
     }
 
     public void testRejectFieldDefinedTwice() throws IOException {
-        String mapping1 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "object")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
-        String mapping2 = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "long")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping1 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "object")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
+        String mapping2 = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "long")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         MapperService mapperService1 = createIndex("test1").mapperService();
         mapperService1.merge(MapperService.SINGLE_MAPPING_NAME, new CompressedXContent(mapping1), MergeReason.MAPPING_UPDATE);
diff --git a/server/src/test/java/org/opensearch/index/query/AbstractQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/AbstractQueryBuilderTests.java
index 78df828df0517..fdbb2ef43aa8e 100644
--- a/server/src/test/java/org/opensearch/index/query/AbstractQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/AbstractQueryBuilderTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
diff --git a/server/src/test/java/org/opensearch/index/query/AbstractTermQueryTestCase.java b/server/src/test/java/org/opensearch/index/query/AbstractTermQueryTestCase.java
index 34a6484bbe481..f7a4c1b48e3d1 100644
--- a/server/src/test/java/org/opensearch/index/query/AbstractTermQueryTestCase.java
+++ b/server/src/test/java/org/opensearch/index/query/AbstractTermQueryTestCase.java
@@ -33,6 +33,7 @@
 package org.opensearch.index.query;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.util.HashMap;
diff --git a/server/src/test/java/org/opensearch/index/query/BoolQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/BoolQueryBuilderTests.java
index a6250118df1cb..d0f26f3026789 100644
--- a/server/src/test/java/org/opensearch/index/query/BoolQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/BoolQueryBuilderTests.java
@@ -37,20 +37,23 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import static org.opensearch.index.query.QueryBuilders.boolQuery;
 import static org.opensearch.index.query.QueryBuilders.termQuery;
@@ -181,7 +184,7 @@ public void testIllegalArguments() {
 
     // https://github.com/elastic/elasticsearch/issues/7240
     public void testEmptyBooleanQuery() throws Exception {
-        XContentBuilder contentBuilder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder contentBuilder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         contentBuilder.startObject().startObject("bool").endObject().endObject();
         try (XContentParser xParser = createParser(contentBuilder)) {
             Query parsedQuery = parseQuery(xParser).toQuery(createShardContext());
@@ -456,4 +459,26 @@ public void testMustRewrite() throws IOException {
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> boolQuery.toQuery(context));
         assertEquals("Rewrite first", e.getMessage());
     }
+
+    public void testVisit() {
+        BoolQueryBuilder boolQueryBuilder = new BoolQueryBuilder();
+        boolQueryBuilder.should(new TermQueryBuilder(TEXT_FIELD_NAME, "should"));
+        boolQueryBuilder.must(new TermQueryBuilder(TEXT_FIELD_NAME, "must1"));
+        boolQueryBuilder.must(new TermQueryBuilder(TEXT_FIELD_NAME, "must2")); // Add a second one to confirm that they both get visited
+        boolQueryBuilder.mustNot(new TermQueryBuilder(TEXT_FIELD_NAME, "mustNot"));
+        boolQueryBuilder.filter(new TermQueryBuilder(TEXT_FIELD_NAME, "filter"));
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        boolQueryBuilder.visit(createTestVisitor(visitedQueries));
+        assertEquals(6, visitedQueries.size());
+        Set<Object> set = new HashSet<>(Arrays.asList("should", "must1", "must2", "mustNot", "filter"));
+
+        for (QueryBuilder qb : visitedQueries) {
+            if (qb instanceof TermQueryBuilder) {
+                set.remove(((TermQueryBuilder) qb).value());
+            }
+        }
+
+        assertEquals(0, set.size());
+
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/BoostingQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/BoostingQueryBuilderTests.java
index 94ded24975be4..66a02a02d4e5b 100644
--- a/server/src/test/java/org/opensearch/index/query/BoostingQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/BoostingQueryBuilderTests.java
@@ -38,6 +38,8 @@
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -153,4 +155,16 @@ public void testMustRewrite() throws IOException {
         e = expectThrows(IllegalStateException.class, () -> queryBuilder2.toQuery(context));
         assertEquals("Rewrite first", e.getMessage());
     }
+
+    public void testVisit() {
+        BoostingQueryBuilder builder = new BoostingQueryBuilder(
+            new TermQueryBuilder("unmapped_field", "value"),
+            new TermQueryBuilder(KEYWORD_FIELD_NAME, "other_value")
+        );
+
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        builder.visit(createTestVisitor(visitedQueries));
+
+        assertEquals(3, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/CombineFunctionTests.java b/server/src/test/java/org/opensearch/index/query/CombineFunctionTests.java
index 31981cce0de91..516a4c7f34517 100644
--- a/server/src/test/java/org/opensearch/index/query/CombineFunctionTests.java
+++ b/server/src/test/java/org/opensearch/index/query/CombineFunctionTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.query;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.CombineFunction;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/query/CombineIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/CombineIntervalsSourceProviderTests.java
index 4d5380221aa82..f1a7cc4e5cfeb 100644
--- a/server/src/test/java/org/opensearch/index/query/CombineIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/CombineIntervalsSourceProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/CommonTermsQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/CommonTermsQueryBuilderTests.java
index b09dc097bd4fd..3b5fd705fcd08 100644
--- a/server/src/test/java/org/opensearch/index/query/CommonTermsQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/CommonTermsQueryBuilderTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.ExtendedCommonTermsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/ConstantScoreQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/ConstantScoreQueryBuilderTests.java
index b3769e599e65a..527413d2513d0 100644
--- a/server/src/test/java/org/opensearch/index/query/ConstantScoreQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/ConstantScoreQueryBuilderTests.java
@@ -35,10 +35,12 @@
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -133,4 +135,12 @@ public void testMustRewrite() throws IOException {
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> queryBuilder.toQuery(context));
         assertEquals("Rewrite first", e.getMessage());
     }
+
+    public void testVisit() {
+        ConstantScoreQueryBuilder queryBuilder = new ConstantScoreQueryBuilder(new TermQueryBuilder("unmapped_field", "foo"));
+        List<QueryBuilder> visitorQueries = new ArrayList<>();
+        queryBuilder.visit(createTestVisitor(visitorQueries));
+
+        assertEquals(2, visitorQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/DisMaxQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/DisMaxQueryBuilderTests.java
index bc8cd6c57b975..cb0df38de5c02 100644
--- a/server/src/test/java/org/opensearch/index/query/DisMaxQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/DisMaxQueryBuilderTests.java
@@ -35,11 +35,13 @@
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.DisjunctionMaxQuery;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
@@ -103,7 +105,10 @@ public void testToQueryInnerPrefixQuery() throws Exception {
             + "    }\n"
             + "}";
         Query query = parseQuery(queryAsString).toQuery(createShardContext());
-        Query expected = new DisjunctionMaxQuery(List.of(new BoostQuery(new PrefixQuery(new Term(TEXT_FIELD_NAME, "sh")), 1.2f)), 0);
+        Query expected = new DisjunctionMaxQuery(
+            List.of(new BoostQuery(new PrefixQuery(new Term(TEXT_FIELD_NAME, "sh"), MultiTermQuery.CONSTANT_SCORE_REWRITE), 1.2f)),
+            0
+        );
         assertEquals(expected, query);
     }
 
@@ -152,4 +157,14 @@ public void testRewriteMultipleTimes() throws IOException {
         assertEquals(rewrittenAgain, expected);
         assertEquals(Rewriteable.rewrite(dismax, createShardContext()), expected);
     }
+
+    public void testVisit() {
+        DisMaxQueryBuilder dismax = new DisMaxQueryBuilder();
+        dismax.add(new WrapperQueryBuilder(new WrapperQueryBuilder(new MatchAllQueryBuilder().toString()).toString()));
+
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        dismax.visit(createTestVisitor(visitedQueries));
+
+        assertEquals(2, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/DisjunctionIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/DisjunctionIntervalsSourceProviderTests.java
index 741725dea7a34..3626b1f4c46d9 100644
--- a/server/src/test/java/org/opensearch/index/query/DisjunctionIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/DisjunctionIntervalsSourceProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilderTests.java
index 402b44ed3df76..db0a7bf1795ff 100644
--- a/server/src/test/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/FieldMaskingSpanQueryBuilderTests.java
@@ -33,14 +33,16 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.index.Term;
+import org.apache.lucene.queries.spans.FieldMaskingSpanQuery;
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.queries.spans.FieldMaskingSpanQuery;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.opensearch.index.query.FieldMaskingSpanQueryBuilder.SPAN_FIELD_MASKING_FIELD;
 import static org.hamcrest.CoreMatchers.equalTo;
@@ -147,4 +149,10 @@ public void testDeprecatedName() throws IOException {
             "Deprecated field [field_masking_span] used, expected [" + SPAN_FIELD_MASKING_FIELD.getPreferredName() + "] instead"
         );
     }
+
+    public void testVisit() {
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        doCreateTestQueryBuilder().visit(createTestVisitor(visitedQueries));
+        assertEquals(2, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/FilterIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/FilterIntervalsSourceProviderTests.java
index 46bc7e43857a3..2835647ada0b6 100644
--- a/server/src/test/java/org/opensearch/index/query/FilterIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/FilterIntervalsSourceProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchModule;
diff --git a/server/src/test/java/org/opensearch/index/query/FuzzyIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/FuzzyIntervalsSourceProviderTests.java
index c3461c162c2d5..c084658c64551 100644
--- a/server/src/test/java/org/opensearch/index/query/FuzzyIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/FuzzyIntervalsSourceProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.IntervalsSourceProvider.Fuzzy;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/FuzzyQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/FuzzyQueryBuilderTests.java
index 5e98a019d0cd8..42c905301c390 100644
--- a/server/src/test/java/org/opensearch/index/query/FuzzyQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/FuzzyQueryBuilderTests.java
@@ -37,8 +37,8 @@
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilderTests.java
index 94cdebdcdf59e..1800beddad2ae 100644
--- a/server/src/test/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/GeoBoundingBoxQueryBuilderTests.java
@@ -45,11 +45,12 @@
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.geo.RandomShapeGenerator;
-import org.locationtech.spatial4j.io.GeohashUtils;
-import org.locationtech.spatial4j.shape.Rectangle;
 
 import java.io.IOException;
 
+import org.locationtech.spatial4j.io.GeohashUtils;
+import org.locationtech.spatial4j.shape.Rectangle;
+
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.notNullValue;
diff --git a/server/src/test/java/org/opensearch/index/query/GeoDistanceQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/GeoDistanceQueryBuilderTests.java
index 8ef34fcb8225b..1b62fef30d255 100644
--- a/server/src/test/java/org/opensearch/index/query/GeoDistanceQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/GeoDistanceQueryBuilderTests.java
@@ -37,19 +37,20 @@
 import org.apache.lucene.search.IndexOrDocValuesQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.unit.DistanceUnit;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.GeoShapeFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.geo.RandomShapeGenerator;
-import org.locationtech.spatial4j.shape.Point;
 
 import java.io.IOException;
 
+import org.locationtech.spatial4j.shape.Point;
+
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.notNullValue;
diff --git a/server/src/test/java/org/opensearch/index/query/GeoPolygonQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/GeoPolygonQueryBuilderTests.java
index ed569e4d0e315..f1d16a0159965 100644
--- a/server/src/test/java/org/opensearch/index/query/GeoPolygonQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/GeoPolygonQueryBuilderTests.java
@@ -37,21 +37,22 @@
 import org.apache.lucene.search.IndexOrDocValuesQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.builders.ShapeBuilder;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.jts.JtsGeometry;
+
 import static org.opensearch.test.StreamsUtils.copyToStringFromClasspath;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.instanceOf;
diff --git a/server/src/test/java/org/opensearch/index/query/GeoShapeQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/GeoShapeQueryBuilderTests.java
index 05fee1c043557..8ad69774ff5b8 100644
--- a/server/src/test/java/org/opensearch/index/query/GeoShapeQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/GeoShapeQueryBuilderTests.java
@@ -40,26 +40,26 @@
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.geo.builders.EnvelopeBuilder;
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.geo.RandomShapeGenerator;
 import org.opensearch.test.geo.RandomShapeGenerator.ShapeType;
 import org.junit.After;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.io.IOException;
 
+import org.locationtech.jts.geom.Coordinate;
+
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.Matchers.anyOf;
@@ -107,7 +107,7 @@ protected GetResponse executeGet(GetRequest getRequest) {
             builder.field(expectedShapePath, indexedShapeToReturn);
             builder.field(randomAlphaOfLengthBetween(10, 20), "something");
             builder.endObject();
-            json = Strings.toString(builder);
+            json = builder.toString();
         } catch (IOException ex) {
             throw new OpenSearchException("boom", ex);
         }
diff --git a/server/src/test/java/org/opensearch/index/query/IdsQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/IdsQueryBuilderTests.java
index 6e03acb68e204..40f4d762f18be 100644
--- a/server/src/test/java/org/opensearch/index/query/IdsQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/IdsQueryBuilderTests.java
@@ -35,8 +35,8 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermInSetQuery;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/InnerHitBuilderTests.java b/server/src/test/java/org/opensearch/index/query/InnerHitBuilderTests.java
index bf5e7e30a1410..729205c9775b4 100644
--- a/server/src/test/java/org/opensearch/index/query/InnerHitBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/InnerHitBuilderTests.java
@@ -31,16 +31,16 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.SearchModule;
@@ -133,7 +133,7 @@ public void testSerializationOrder() throws Exception {
     public void testFromAndToXContent() throws Exception {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             InnerHitBuilder innerHit = randomInnerHits();
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             innerHit.toXContent(builder, ToXContent.EMPTY_PARAMS);
             // fields is printed out as an object but parsed into a List where order matters, we disable shuffling
             XContentBuilder shuffled = shuffleXContent(builder, "fields");
@@ -237,12 +237,9 @@ static InnerHitBuilder mutate(InnerHitBuilder original) throws IOException {
         });
         modifiers.add(() -> {
             if (randomBoolean()) {
-                copy.setScriptFields(
-                    randomValueOtherThan(
-                        copy.getScriptFields(),
-                        () -> { return new HashSet<>(randomListStuff(16, InnerHitBuilderTests::randomScript)); }
-                    )
-                );
+                copy.setScriptFields(randomValueOtherThan(copy.getScriptFields(), () -> {
+                    return new HashSet<>(randomListStuff(16, InnerHitBuilderTests::randomScript));
+                }));
             } else {
                 SearchSourceBuilder.ScriptField script = randomScript();
                 copy.addScriptField(script.fieldName(), script.script());
diff --git a/server/src/test/java/org/opensearch/index/query/IntervalBuilderTests.java b/server/src/test/java/org/opensearch/index/query/IntervalBuilderTests.java
index b31bcc10a28cc..3503552ee442b 100644
--- a/server/src/test/java/org/opensearch/index/query/IntervalBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/IntervalBuilderTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.analysis.CachingTokenFilter;
-import org.apache.lucene.tests.analysis.CannedTokenStream;
-import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.queries.intervals.Intervals;
 import org.apache.lucene.queries.intervals.IntervalsSource;
+import org.apache.lucene.tests.analysis.CannedTokenStream;
+import org.apache.lucene.tests.analysis.Token;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/IntervalQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/IntervalQueryBuilderTests.java
index d7f57eef5e039..660b8a3aa8994 100644
--- a/server/src/test/java/org/opensearch/index/query/IntervalQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/IntervalQueryBuilderTests.java
@@ -44,13 +44,12 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
 import org.apache.lucene.util.automaton.RegExp;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptContext;
@@ -109,7 +108,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge("_doc", new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("_doc", new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     private static IntervalsSourceProvider createRandomSource(int depth, boolean useScripts) {
diff --git a/server/src/test/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilderTests.java
index 8a6b09b1ea925..46a0192164817 100644
--- a/server/src/test/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MatchBoolPrefixQueryBuilderTests.java
@@ -32,17 +32,18 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.FuzzyQuery;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.test.AbstractQueryTestCase;
 
@@ -179,6 +180,11 @@ public void testIllegalValues() {
         }
     }
 
+    public void testDefaultFuzziness() {
+        MatchBoolPrefixQueryBuilder matchBoolPrefixQueryBuilder = new MatchBoolPrefixQueryBuilder(TEXT_FIELD_NAME, "text").fuzziness(null);
+        assertNull(matchBoolPrefixQueryBuilder.fuzziness());
+    }
+
     public void testFromSimpleJson() throws IOException {
         final String simple = "{" + "\"match_bool_prefix\": {" + "\"fieldName\": \"fieldValue\"" + "}" + "}";
         final String expected = "{"
@@ -263,7 +269,7 @@ public void testAnalysis() throws Exception {
             asList(
                 new TermQuery(new Term(TEXT_FIELD_NAME, "foo")),
                 new TermQuery(new Term(TEXT_FIELD_NAME, "bar")),
-                new PrefixQuery(new Term(TEXT_FIELD_NAME, "baz"))
+                new PrefixQuery(new Term(TEXT_FIELD_NAME, "baz"), MultiTermQuery.CONSTANT_SCORE_REWRITE)
             )
         );
     }
@@ -280,7 +286,7 @@ public void testAnalysisSynonym() throws Exception {
                 new SynonymQuery.Builder(TEXT_FIELD_NAME).addTerm(new Term(TEXT_FIELD_NAME, "dogs"))
                     .addTerm(new Term(TEXT_FIELD_NAME, "dog"))
                     .build(),
-                new PrefixQuery(new Term(TEXT_FIELD_NAME, "red"))
+                new PrefixQuery(new Term(TEXT_FIELD_NAME, "red"), MultiTermQuery.CONSTANT_SCORE_REWRITE)
             )
         );
     }
@@ -288,7 +294,7 @@ public void testAnalysisSynonym() throws Exception {
     public void testAnalysisSingleTerm() throws Exception {
         final MatchBoolPrefixQueryBuilder builder = new MatchBoolPrefixQueryBuilder(TEXT_FIELD_NAME, "foo");
         final Query query = builder.toQuery(createShardContext());
-        assertThat(query, equalTo(new PrefixQuery(new Term(TEXT_FIELD_NAME, "foo"))));
+        assertThat(query, equalTo(new PrefixQuery(new Term(TEXT_FIELD_NAME, "foo"), MultiTermQuery.CONSTANT_SCORE_REWRITE)));
     }
 
     private static void assertBooleanQuery(Query actual, List<Query> expectedClauseQueries) {
diff --git a/server/src/test/java/org/opensearch/index/query/MatchIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/MatchIntervalsSourceProviderTests.java
index 3f9d075d72532..03e5b3d50357e 100644
--- a/server/src/test/java/org/opensearch/index/query/MatchIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MatchIntervalsSourceProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilderTests.java
index 6bff0b74af6d1..39aa5efa4a83e 100644
--- a/server/src/test/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MatchPhrasePrefixQueryBuilderTests.java
@@ -36,8 +36,8 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
 import org.opensearch.test.AbstractQueryTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/MatchPhraseQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MatchPhraseQueryBuilderTests.java
index defe8e335a90f..f8d5d2ce3d062 100644
--- a/server/src/test/java/org/opensearch/index/query/MatchPhraseQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MatchPhraseQueryBuilderTests.java
@@ -40,7 +40,7 @@
 import org.apache.lucene.search.PointRangeQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.search.MatchQuery.ZeroTermsQuery;
 import org.opensearch.test.AbstractQueryTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/query/MatchQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MatchQueryBuilderTests.java
index d6cd157d6f84e..04dcacbd86ac5 100644
--- a/server/src/test/java/org/opensearch/index/query/MatchQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MatchQueryBuilderTests.java
@@ -33,8 +33,7 @@
 package org.opensearch.index.query;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.CannedBinaryTokenStream;
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
+import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.ExtendedCommonTermsQuery;
 import org.apache.lucene.queries.spans.SpanNearQuery;
@@ -51,13 +50,15 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.tests.analysis.CannedBinaryTokenStream;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.graph.GraphTokenStreamFiniteStrings;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.search.MatchQuery;
@@ -69,6 +70,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -326,6 +328,25 @@ public void testFuzzinessOnNonStringField() throws Exception {
         query.toQuery(context); // no exception
     }
 
+    public void testMatchQueryWithNoSidePath() throws Exception {
+        QueryShardContext testContext = createShardContext();
+        final MatchQuery testMatchQuery = new MatchQuery(testContext);
+        MockGraphAnalyzer mockAnalyzer = new MockGraphAnalyzer(createGiantGraphWithNoSide());
+        testMatchQuery.setAnalyzer(mockAnalyzer);
+        testMatchQuery.setAutoGenerateSynonymsPhraseQuery(true);
+        GraphTokenStreamFiniteStrings graph = new GraphTokenStreamFiniteStrings(mockAnalyzer.getTokenStream());
+        Iterator<TokenStream> graphIt = graph.getFiniteStrings();
+        assertEquals(graphIt.hasNext(), false);
+        String testField = "Gas Lift Storage Bed Frame with Arched Bed Head in King";
+        String testValue = "head board, bed head, bedhead, headboard";
+        testMatchQuery.parse(Type.BOOLEAN, testField, testValue); // no exception
+    }
+
+    public void testDefaultFuzziness() {
+        MatchQueryBuilder matchQueryBuilder = new MatchQueryBuilder("text", TEXT_FIELD_NAME).fuzziness(null);
+        assertNull(matchQueryBuilder.fuzziness());
+    }
+
     public void testExactOnUnsupportedField() throws Exception {
         MatchQueryBuilder query = new MatchQueryBuilder(GEO_POINT_FIELD_NAME, "2,3");
         QueryShardContext context = createShardContext();
@@ -389,9 +410,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         mapperService.merge(
             "_doc",
             new CompressedXContent(
-                Strings.toString(
-                    PutMappingRequest.simpleMapping("string_boost", "type=text", "string_no_pos", "type=text,index_options=docs")
-                )
+                PutMappingRequest.simpleMapping("string_boost", "type=text", "string_no_pos", "type=text,index_options=docs").toString()
             ),
             MapperService.MergeReason.MAPPING_UPDATE
         );
@@ -537,12 +556,18 @@ private static class MockGraphAnalyzer extends Analyzer {
 
         MockGraphAnalyzer(CannedBinaryTokenStream.BinaryToken[] tokens) {
             this.tokenStream = new CannedBinaryTokenStream(tokens);
+
         }
 
         @Override
         protected TokenStreamComponents createComponents(String fieldName) {
             return new TokenStreamComponents(r -> {}, tokenStream);
         }
+
+        public CannedBinaryTokenStream getTokenStream() {
+            return this.tokenStream;
+        }
+
     }
 
     /**
@@ -565,6 +590,14 @@ private static CannedBinaryTokenStream.BinaryToken[] createGiantGraph(int numPos
         return tokens.toArray(new CannedBinaryTokenStream.BinaryToken[0]);
     }
 
+    /**
+     * Creates a graph token stream with no side path.
+     **/
+    private static CannedBinaryTokenStream.BinaryToken[] createGiantGraphWithNoSide() {
+        List<CannedBinaryTokenStream.BinaryToken> tokens = new ArrayList<>();
+        return tokens.toArray(new CannedBinaryTokenStream.BinaryToken[0]);
+    }
+
     /**
      * Creates a graph token stream with {@link BooleanQuery#getMaxClauseCount()}
      * expansions at the last position.
diff --git a/server/src/test/java/org/opensearch/index/query/MoreLikeThisQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MoreLikeThisQueryBuilderTests.java
index 2061378c3f54f..02c6ad46653d6 100644
--- a/server/src/test/java/org/opensearch/index/query/MoreLikeThisQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MoreLikeThisQueryBuilderTests.java
@@ -45,17 +45,16 @@
 import org.opensearch.action.termvectors.TermVectorsRequest;
 import org.opensearch.action.termvectors.TermVectorsResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lucene.search.MoreLikeThisQuery;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.util.CollectionUtils;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.query.MoreLikeThisQueryBuilder.Item;
 import org.opensearch.test.AbstractQueryTestCase;
@@ -271,7 +270,7 @@ private static Fields generateFields(String[] fieldNames, String text) throws IO
         for (String fieldName : fieldNames) {
             index.addField(fieldName, text, new WhitespaceAnalyzer());
         }
-        return index.createSearcher().getIndexReader().getTermVectors(0);
+        return index.createSearcher().getIndexReader().termVectors().get(0);
     }
 
     @Override
@@ -397,7 +396,7 @@ public void testItemCopy() throws IOException {
 
     public void testItemFromXContent() throws IOException {
         Item expectedItem = generateRandomItem();
-        String json = Strings.toString(expectedItem.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS));
+        String json = expectedItem.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS).toString();
         XContentParser parser = createParser(JsonXContent.jsonXContent, json);
         Item newItem = Item.parse(parser, new Item());
         assertEquals(expectedItem, newItem);
diff --git a/server/src/test/java/org/opensearch/index/query/MultiMatchQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/MultiMatchQueryBuilderTests.java
index ec04ee8fd3d6d..e1391393f44fa 100644
--- a/server/src/test/java/org/opensearch/index/query/MultiMatchQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/MultiMatchQueryBuilderTests.java
@@ -48,10 +48,10 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.query.MultiMatchQueryBuilder.Type;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.test.AbstractQueryTestCase;
@@ -365,6 +365,11 @@ public void testFuzzinessNotAllowedTypes() throws IOException {
         }
     }
 
+    public void testDefaultFuzziness() {
+        MultiMatchQueryBuilder multiMatchQueryBuilder = new MultiMatchQueryBuilder("text", TEXT_FIELD_NAME).fuzziness(null);
+        assertNull(multiMatchQueryBuilder.fuzziness());
+    }
+
     public void testQueryParameterArrayException() {
         String json = "{\n"
             + "  \"multi_match\" : {\n"
diff --git a/server/src/test/java/org/opensearch/index/query/NestedQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/NestedQueryBuilderTests.java
index abc3e0bb8c4c3..ff6eb74f5443e 100644
--- a/server/src/test/java/org/opensearch/index/query/NestedQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/NestedQueryBuilderTests.java
@@ -40,7 +40,6 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.IndexSettings;
@@ -67,6 +66,8 @@
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 public class NestedQueryBuilderTests extends AbstractQueryTestCase<NestedQueryBuilder> {
@@ -76,26 +77,24 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         mapperService.merge(
             "_doc",
             new CompressedXContent(
-                Strings.toString(
-                    PutMappingRequest.simpleMapping(
-                        TEXT_FIELD_NAME,
-                        "type=text",
-                        INT_FIELD_NAME,
-                        "type=integer",
-                        DOUBLE_FIELD_NAME,
-                        "type=double",
-                        BOOLEAN_FIELD_NAME,
-                        "type=boolean",
-                        DATE_FIELD_NAME,
-                        "type=date",
-                        OBJECT_FIELD_NAME,
-                        "type=object",
-                        GEO_POINT_FIELD_NAME,
-                        "type=geo_point",
-                        "nested1",
-                        "type=nested"
-                    )
-                )
+                PutMappingRequest.simpleMapping(
+                    TEXT_FIELD_NAME,
+                    "type=text",
+                    INT_FIELD_NAME,
+                    "type=integer",
+                    DOUBLE_FIELD_NAME,
+                    "type=double",
+                    BOOLEAN_FIELD_NAME,
+                    "type=boolean",
+                    DATE_FIELD_NAME,
+                    "type=date",
+                    OBJECT_FIELD_NAME,
+                    "type=object",
+                    GEO_POINT_FIELD_NAME,
+                    "type=geo_point",
+                    "nested1",
+                    "type=nested"
+                ).toString()
             ),
             MapperService.MergeReason.MAPPING_UPDATE
         );
@@ -410,4 +409,22 @@ public void testDisallowExpensiveQueries() {
         OpenSearchException e = expectThrows(OpenSearchException.class, () -> queryBuilder.toQuery(queryShardContext));
         assertEquals("[joining] queries cannot be executed when 'search.allow_expensive_queries' is set to false.", e.getMessage());
     }
+
+    public void testSetParentFilterInContext() throws Exception {
+        QueryShardContext queryShardContext = createShardContext();
+        QueryBuilder innerQueryBuilder = spy(new MatchAllQueryBuilderTests().createTestQueryBuilder());
+        when(innerQueryBuilder.toQuery(queryShardContext)).thenAnswer(invoke -> {
+            QueryShardContext context = invoke.getArgument(0);
+            if (context.getParentFilter() == null) {
+                throw new Exception("Expect parent filter to be non-null");
+            }
+            return invoke.callRealMethod();
+        });
+        NestedQueryBuilder nqb = new NestedQueryBuilder("nested1", innerQueryBuilder, RandomPicks.randomFrom(random(), ScoreMode.values()));
+
+        assertNull(queryShardContext.getParentFilter());
+        nqb.rewrite(queryShardContext).toQuery(queryShardContext);
+        assertNull(queryShardContext.getParentFilter());
+        verify(innerQueryBuilder).toQuery(queryShardContext);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/OperatorTests.java b/server/src/test/java/org/opensearch/index/query/OperatorTests.java
index a6293cd833099..5d90338fe5278 100644
--- a/server/src/test/java/org/opensearch/index/query/OperatorTests.java
+++ b/server/src/test/java/org/opensearch/index/query/OperatorTests.java
@@ -35,7 +35,7 @@
 import org.apache.lucene.queryparser.classic.QueryParser;
 import org.apache.lucene.search.BooleanClause;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/query/PrefixIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/PrefixIntervalsSourceProviderTests.java
index fede1f98956bc..93dd229783805 100644
--- a/server/src/test/java/org/opensearch/index/query/PrefixIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/PrefixIntervalsSourceProviderTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/PrefixQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/PrefixQueryBuilderTests.java
index 48b309ea4eca3..52093e65d0122 100644
--- a/server/src/test/java/org/opensearch/index/query/PrefixQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/PrefixQueryBuilderTests.java
@@ -37,7 +37,7 @@
 import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.hamcrest.Matchers;
 
@@ -130,7 +130,7 @@ public void testNumeric() throws Exception {
         QueryShardContext context = createShardContext();
         QueryShardException e = expectThrows(QueryShardException.class, () -> query.toQuery(context));
         assertEquals(
-            "Can only use prefix queries on keyword, text and wildcard fields - not on [mapped_int] which is of type [integer]",
+            "Can only use prefix queries on keyword and text fields - not on [mapped_int] which is of type [integer]",
             e.getMessage()
         );
     }
diff --git a/server/src/test/java/org/opensearch/index/query/QueryBuilderVisitorTests.java b/server/src/test/java/org/opensearch/index/query/QueryBuilderVisitorTests.java
new file mode 100644
index 0000000000000..7849d3985ca59
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/query/QueryBuilderVisitorTests.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.query;
+
+import org.apache.lucene.search.BooleanClause;
+import org.opensearch.test.AbstractBuilderTestCase;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class QueryBuilderVisitorTests extends AbstractBuilderTestCase {
+
+    public void testNoOpsVisitor() {
+        BoolQueryBuilder boolQueryBuilder = new BoolQueryBuilder();
+
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        QueryBuilderVisitor qbv = createTestVisitor(visitedQueries);
+        boolQueryBuilder.visit(qbv);
+        QueryBuilderVisitor subQbv = qbv.getChildVisitor(BooleanClause.Occur.MUST_NOT);
+        assertEquals(0, visitedQueries.size());
+        assertEquals(qbv, subQbv);
+    }
+
+    protected static QueryBuilderVisitor createTestVisitor(List<QueryBuilder> visitedQueries) {
+        return QueryBuilderVisitor.NO_OP_VISITOR;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/query/QueryShardContextTests.java b/server/src/test/java/org/opensearch/index/query/QueryShardContextTests.java
index 2f8ab12a2f3e3..c819d35872c6e 100644
--- a/server/src/test/java/org/opensearch/index/query/QueryShardContextTests.java
+++ b/server/src/test/java/org/opensearch/index/query/QueryShardContextTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.IndexSearcher;
@@ -46,15 +45,16 @@
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
diff --git a/server/src/test/java/org/opensearch/index/query/QueryShardExceptionTests.java b/server/src/test/java/org/opensearch/index/query/QueryShardExceptionTests.java
index da4bfa9f1c390..d7549d8c77340 100644
--- a/server/src/test/java/org/opensearch/index/query/QueryShardExceptionTests.java
+++ b/server/src/test/java/org/opensearch/index/query/QueryShardExceptionTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.CoreMatchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/query/QueryStringQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/QueryStringQueryBuilderTests.java
index 393d4cb3f2121..af4a34aa98116 100644
--- a/server/src/test/java/org/opensearch/index/query/QueryStringQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/QueryStringQueryBuilderTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.Term;
@@ -61,6 +60,7 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TermRangeQuery;
 import org.apache.lucene.search.WildcardQuery;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
@@ -68,12 +68,11 @@
 import org.apache.lucene.util.automaton.TooComplexToDeterminizeException;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.search.QueryStringQueryParser;
@@ -116,7 +115,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge("_doc", new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("_doc", new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     @Override
@@ -567,7 +566,12 @@ public void testToQueryWildcardQuery() throws Exception {
                 .add(
                     new BooleanQuery.Builder().add(new BooleanClause(new TermQuery(new Term(TEXT_FIELD_NAME, "foo")), defaultOp))
                         .add(new BooleanClause(new TermQuery(new Term(TEXT_FIELD_NAME, "bar")), defaultOp))
-                        .add(new BooleanClause(new PrefixQuery(new Term(TEXT_FIELD_NAME, "foobar")), defaultOp))
+                        .add(
+                            new BooleanClause(
+                                new PrefixQuery(new Term(TEXT_FIELD_NAME, "foobar"), MultiTermQuery.CONSTANT_SCORE_REWRITE),
+                                defaultOp
+                            )
+                        )
                         .build(),
                     defaultOp
                 )
@@ -579,6 +583,8 @@ public void testToQueryWildcardQuery() throws Exception {
 
     public void testToQueryWildcardWithIndexedPrefixes() throws Exception {
         QueryStringQueryParser queryParser = new QueryStringQueryParser(createShardContext(), "prefix_field");
+        queryParser.setMultiTermRewriteMethod(MultiTermQuery.CONSTANT_SCORE_REWRITE);
+
         Query query = queryParser.parse("foo*");
         Query expectedQuery = new ConstantScoreQuery(new TermQuery(new Term("prefix_field._index_prefix", "foo")));
         assertThat(query, equalTo(expectedQuery));
@@ -586,19 +592,26 @@ public void testToQueryWildcardWithIndexedPrefixes() throws Exception {
         query = queryParser.parse("g*");
         Automaton a = Operations.concatenate(Arrays.asList(Automata.makeChar('g'), Automata.makeAnyChar()));
         expectedQuery = new ConstantScoreQuery(
-            new BooleanQuery.Builder().add(new AutomatonQuery(new Term("prefix_field._index_prefix", "g*"), a), Occur.SHOULD)
-                .add(new TermQuery(new Term("prefix_field", "g")), Occur.SHOULD)
-                .build()
+            new BooleanQuery.Builder().add(
+                new AutomatonQuery(
+                    new Term("prefix_field._index_prefix", "g*"),
+                    a,
+                    Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+                    false,
+                    MultiTermQuery.CONSTANT_SCORE_REWRITE
+                ),
+                Occur.SHOULD
+            ).add(new TermQuery(new Term("prefix_field", "g")), Occur.SHOULD).build()
         );
         assertThat(query, equalTo(expectedQuery));
     }
 
-    public void testToQueryWilcardQueryWithSynonyms() throws Exception {
+    public void testToQueryWildcardQueryWithSynonyms() throws Exception {
         for (Operator op : Operator.values()) {
             BooleanClause.Occur defaultOp = op.toBooleanClauseOccur();
             QueryStringQueryParser queryParser = new QueryStringQueryParser(createShardContext(), TEXT_FIELD_NAME);
             queryParser.setAnalyzeWildcard(true);
-            queryParser.setMultiTermRewriteMethod(MultiTermQuery.CONSTANT_SCORE_REWRITE);
+            queryParser.setMultiTermRewriteMethod(MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE);
             queryParser.setDefaultOperator(op.toQueryParserOperator());
             queryParser.setForceAnalyzer(new MockRepeatAnalyzer());
             Query query = queryParser.parse("first foo-bar-foobar* last");
@@ -803,7 +816,7 @@ public void testToQueryRegExpQueryMaxDeterminizedStatesParsing() throws Exceptio
         assertThat(e.getMessage(), containsString("would require more than 10 effort"));
     }
 
-    public void testToQueryFuzzyQueryAutoFuziness() throws Exception {
+    public void testToQueryFuzzyQueryAutoFuzziness() throws Exception {
         for (int i = 0; i < 3; i++) {
             final int len;
             final int expectedEdits;
@@ -828,7 +841,6 @@ public void testToQueryFuzzyQueryAutoFuziness() throws Exception {
             String queryString = new String(bytes);
             for (int j = 0; j < 2; j++) {
                 Query query = queryStringQuery(queryString + (j == 0 ? "~" : "~auto")).defaultField(TEXT_FIELD_NAME)
-                    .fuzziness(Fuzziness.AUTO)
                     .toQuery(createShardContext());
                 assertThat(query, instanceOf(FuzzyQuery.class));
                 FuzzyQuery fuzzyQuery = (FuzzyQuery) query;
@@ -868,12 +880,17 @@ public void testFuzzyNumeric() throws Exception {
         query.toQuery(context); // no exception
     }
 
+    public void testDefaultFuzziness() {
+        QueryStringQueryBuilder queryStringQueryBuilder = new QueryStringQueryBuilder(TEXT_FIELD_NAME).fuzziness(null);
+        assertNull(queryStringQueryBuilder.fuzziness());
+    }
+
     public void testPrefixNumeric() throws Exception {
         QueryStringQueryBuilder query = queryStringQuery("12*").defaultField(INT_FIELD_NAME);
         QueryShardContext context = createShardContext();
         QueryShardException e = expectThrows(QueryShardException.class, () -> query.toQuery(context));
         assertEquals(
-            "Can only use prefix queries on keyword, text and wildcard fields - not on [mapped_int] which is of type [integer]",
+            "Can only use prefix queries on keyword and text fields - not on [mapped_int] which is of type [integer]",
             e.getMessage()
         );
         query.lenient(true);
@@ -1095,9 +1112,7 @@ public void testDisabledFieldNamesField() throws Exception {
         context.getMapperService()
             .merge(
                 "_doc",
-                new CompressedXContent(
-                    Strings.toString(PutMappingRequest.simpleMapping("foo", "type=text", "_field_names", "enabled=false"))
-                ),
+                new CompressedXContent(PutMappingRequest.simpleMapping("foo", "type=text", "_field_names", "enabled=false").toString()),
                 MapperService.MergeReason.MAPPING_UPDATE
             );
 
@@ -1111,9 +1126,7 @@ public void testDisabledFieldNamesField() throws Exception {
             context.getMapperService()
                 .merge(
                     "_doc",
-                    new CompressedXContent(
-                        Strings.toString(PutMappingRequest.simpleMapping("foo", "type=text", "_field_names", "enabled=true"))
-                    ),
+                    new CompressedXContent(PutMappingRequest.simpleMapping("foo", "type=text", "_field_names", "enabled=true").toString()),
                     MapperService.MergeReason.MAPPING_UPDATE
                 );
         }
@@ -1153,15 +1166,29 @@ public void testFromJson() throws IOException {
     public void testExpandedTerms() throws Exception {
         // Prefix
         Query query = new QueryStringQueryBuilder("aBc*").field(TEXT_FIELD_NAME).analyzer("whitespace").toQuery(createShardContext());
-        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "aBc")), query);
+        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "aBc"), MultiTermQuery.CONSTANT_SCORE_REWRITE), query);
         query = new QueryStringQueryBuilder("aBc*").field(TEXT_FIELD_NAME).analyzer("standard").toQuery(createShardContext());
-        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "abc")), query);
+        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "abc"), MultiTermQuery.CONSTANT_SCORE_REWRITE), query);
 
         // Wildcard
         query = new QueryStringQueryBuilder("aBc*D").field(TEXT_FIELD_NAME).analyzer("whitespace").toQuery(createShardContext());
-        assertEquals(new WildcardQuery(new Term(TEXT_FIELD_NAME, "aBc*D")), query);
+        assertEquals(
+            new WildcardQuery(
+                new Term(TEXT_FIELD_NAME, "aBc*D"),
+                Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+                MultiTermQuery.CONSTANT_SCORE_REWRITE
+            ),
+            query
+        );
         query = new QueryStringQueryBuilder("aBc*D").field(TEXT_FIELD_NAME).analyzer("standard").toQuery(createShardContext());
-        assertEquals(new WildcardQuery(new Term(TEXT_FIELD_NAME, "abc*d")), query);
+        assertEquals(
+            new WildcardQuery(
+                new Term(TEXT_FIELD_NAME, "abc*d"),
+                Operations.DEFAULT_DETERMINIZE_WORK_LIMIT,
+                MultiTermQuery.CONSTANT_SCORE_REWRITE
+            ),
+            query
+        );
 
         // Fuzzy
         query = new QueryStringQueryBuilder("aBc~1").field(TEXT_FIELD_NAME).analyzer("whitespace").toQuery(createShardContext());
@@ -1403,7 +1430,10 @@ public void testEnablePositionIncrement() throws Exception {
 
     public void testWithPrefixStopWords() throws Exception {
         Query query = new QueryStringQueryBuilder("the* quick fox").field(TEXT_FIELD_NAME).analyzer("stop").toQuery(createShardContext());
-        BooleanQuery expected = new BooleanQuery.Builder().add(new PrefixQuery(new Term(TEXT_FIELD_NAME, "the")), Occur.SHOULD)
+        BooleanQuery expected = new BooleanQuery.Builder().add(
+            new PrefixQuery(new Term(TEXT_FIELD_NAME, "the"), MultiTermQuery.CONSTANT_SCORE_REWRITE),
+            Occur.SHOULD
+        )
             .add(new TermQuery(new Term(TEXT_FIELD_NAME, "quick")), Occur.SHOULD)
             .add(new TermQuery(new Term(TEXT_FIELD_NAME, "fox")), Occur.SHOULD)
             .build();
@@ -1484,7 +1514,7 @@ public void testAnalyzedPrefix() throws Exception {
             .analyzer("standard")
             .analyzeWildcard(true)
             .toQuery(createShardContext());
-        Query expected = new PrefixQuery(new Term(TEXT_FIELD_NAME, "quick"));
+        Query expected = new PrefixQuery(new Term(TEXT_FIELD_NAME, "quick"), MultiTermQuery.CONSTANT_SCORE_REWRITE);
         assertEquals(expected, query);
     }
 
diff --git a/server/src/test/java/org/opensearch/index/query/RangeQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/RangeQueryBuilderTests.java
index 0f451fda7b9fb..2ac5ea8c585ea 100644
--- a/server/src/test/java/org/opensearch/index/query/RangeQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RangeQueryBuilderTests.java
@@ -45,9 +45,9 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TermRangeQuery;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.lucene.BytesRefs;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/index/query/RangeQueryRewriteTests.java b/server/src/test/java/org/opensearch/index/query/RangeQueryRewriteTests.java
index 171fe8ef794f9..fc550cfd1916e 100644
--- a/server/src/test/java/org/opensearch/index/query/RangeQueryRewriteTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RangeQueryRewriteTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.search.IndexSearcher;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.xcontent.XContentFactory;
@@ -77,18 +76,17 @@ public void testRewriteMissingField() throws Exception {
 
     public void testRewriteMissingReader() throws Exception {
         IndexService indexService = createIndex("test");
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "date")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "date")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         indexService.mapperService().merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
         QueryRewriteContext context = new QueryShardContext(
             0,
@@ -116,18 +114,17 @@ public void testRewriteMissingReader() throws Exception {
 
     public void testRewriteEmptyReader() throws Exception {
         IndexService indexService = createIndex("test");
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("foo")
-                .field("type", "date")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("foo")
+            .field("type", "date")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         indexService.mapperService().merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
         IndexReader reader = new MultiReader();
         QueryRewriteContext context = new QueryShardContext(
diff --git a/server/src/test/java/org/opensearch/index/query/RegexpIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/RegexpIntervalsSourceProviderTests.java
index bf6809e5cb446..ee9839bf96668 100644
--- a/server/src/test/java/org/opensearch/index/query/RegexpIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RegexpIntervalsSourceProviderTests.java
@@ -8,17 +8,17 @@
 
 package org.opensearch.index.query;
 
-import static org.opensearch.index.query.IntervalsSourceProvider.Regexp;
-import static org.opensearch.index.query.IntervalsSourceProvider.fromXContent;
-
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import static org.opensearch.index.query.IntervalsSourceProvider.Regexp;
+import static org.opensearch.index.query.IntervalsSourceProvider.fromXContent;
+
 public class RegexpIntervalsSourceProviderTests extends AbstractSerializingTestCase<Regexp> {
     private static final List<String> FLAGS = Arrays.asList("INTERSECTION", "COMPLEMENT", "EMPTY", "ANYSTRING", "INTERVAL", "NONE");
 
diff --git a/server/src/test/java/org/opensearch/index/query/RegexpQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/RegexpQueryBuilderTests.java
index 31bb078fa4c1d..47bdf3ccaf77c 100644
--- a/server/src/test/java/org/opensearch/index/query/RegexpQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RegexpQueryBuilderTests.java
@@ -34,7 +34,7 @@
 
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.RegexpQuery;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/RewriteableTests.java b/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
index eba4e11881aee..6385a57f9f370 100644
--- a/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.SetOnce;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/ScoreModeTests.java b/server/src/test/java/org/opensearch/index/query/ScoreModeTests.java
index f6be1868b49e5..a71b8bea24b2f 100644
--- a/server/src/test/java/org/opensearch/index/query/ScoreModeTests.java
+++ b/server/src/test/java/org/opensearch/index/query/ScoreModeTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.query;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/query/ScriptQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/ScriptQueryBuilderTests.java
index 9b37bdd3e7d1c..446cb25d8bb97 100644
--- a/server/src/test/java/org/opensearch/index/query/ScriptQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/ScriptQueryBuilderTests.java
@@ -34,7 +34,7 @@
 
 import org.apache.lucene.search.Query;
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
diff --git a/server/src/test/java/org/opensearch/index/query/ScriptScoreQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/ScriptScoreQueryBuilderTests.java
index 320ff20b2ef5d..29d45fb42ffcc 100644
--- a/server/src/test/java/org/opensearch/index/query/ScriptScoreQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/ScriptScoreQueryBuilderTests.java
@@ -43,7 +43,9 @@
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.List;
 
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -140,4 +142,11 @@ public void testDisallowExpensiveQueries() {
         OpenSearchException e = expectThrows(OpenSearchException.class, () -> queryBuilder.toQuery(queryShardContext));
         assertEquals("[script score] queries cannot be executed when 'search.allow_expensive_queries' is set to false.", e.getMessage());
     }
+
+    public void testVisit() {
+        ScriptScoreQueryBuilder scriptQueryBuilder = doCreateTestQueryBuilder();
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        scriptQueryBuilder.visit(createTestVisitor(visitedQueries));
+        assertEquals(2, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SimpleQueryStringBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SimpleQueryStringBuilderTests.java
index 1101da8de70fe..859a970b02a02 100644
--- a/server/src/test/java/org/opensearch/index/query/SimpleQueryStringBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SimpleQueryStringBuilderTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.spans.SpanNearQuery;
@@ -45,11 +44,13 @@
 import org.apache.lucene.search.DisjunctionMaxQuery;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
+import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.PhraseQuery;
 import org.apache.lucene.search.PrefixQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
@@ -451,9 +452,9 @@ public void testMinimumShouldMatch() throws IOException {
     public void testExpandedTerms() throws Exception {
         // Prefix
         Query query = new SimpleQueryStringBuilder("aBc*").field(TEXT_FIELD_NAME).analyzer("whitespace").toQuery(createShardContext());
-        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "aBc")), query);
+        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "aBc"), MultiTermQuery.CONSTANT_SCORE_REWRITE), query);
         query = new SimpleQueryStringBuilder("aBc*").field(TEXT_FIELD_NAME).analyzer("standard").toQuery(createShardContext());
-        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "abc")), query);
+        assertEquals(new PrefixQuery(new Term(TEXT_FIELD_NAME, "abc"), MultiTermQuery.CONSTANT_SCORE_REWRITE), query);
 
         // Fuzzy
         query = new SimpleQueryStringBuilder("aBc~1").field(TEXT_FIELD_NAME).analyzer("whitespace").toQuery(createShardContext());
@@ -712,8 +713,12 @@ public void testLenientToPrefixQuery() throws Exception {
             .lenient(true)
             .toQuery(createShardContext());
         List<Query> expectedQueries = new ArrayList<>();
-        expectedQueries.add(new MatchNoDocsQuery(""));
-        expectedQueries.add(new PrefixQuery(new Term(TEXT_FIELD_NAME, "t")));
+        expectedQueries.add(
+            new MatchNoDocsQuery(
+                "failed query, caused by Can only use prefix queries on keyword and text fields - not on [mapped_date] which is of type [date]"
+            )
+        );
+        expectedQueries.add(new PrefixQuery(new Term(TEXT_FIELD_NAME, "t"), MultiTermQuery.CONSTANT_SCORE_REWRITE));
         DisjunctionMaxQuery expected = new DisjunctionMaxQuery(expectedQueries, 1.0f);
         assertEquals(expected, query);
     }
@@ -766,7 +771,7 @@ public void testWithStopWords() throws Exception {
     public void testWithPrefixStopWords() throws Exception {
         Query query = new SimpleQueryStringBuilder("the* quick fox").field(TEXT_FIELD_NAME).analyzer("stop").toQuery(createShardContext());
         BooleanQuery expected = new BooleanQuery.Builder().add(
-            new PrefixQuery(new Term(TEXT_FIELD_NAME, "the")),
+            new PrefixQuery(new Term(TEXT_FIELD_NAME, "the"), MultiTermQuery.CONSTANT_SCORE_REWRITE),
             BooleanClause.Occur.SHOULD
         )
             .add(new TermQuery(new Term(TEXT_FIELD_NAME, "quick")), BooleanClause.Occur.SHOULD)
diff --git a/server/src/test/java/org/opensearch/index/query/SpanContainingQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanContainingQueryBuilderTests.java
index 33be236b45ab6..2a5441b0ea932 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanContainingQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanContainingQueryBuilderTests.java
@@ -34,10 +34,12 @@
 
 import org.apache.lucene.queries.spans.SpanContainingQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -192,4 +194,10 @@ public void testFromJsonWithNonDefaultBoostInLittleQuery() {
             equalTo("span_containing [little] as a nested span clause can't have non-default boost value [2.0]")
         );
     }
+
+    public void testVisit() {
+        List<QueryBuilder> visitorQueries = new ArrayList<>();
+        doCreateTestQueryBuilder().visit(createTestVisitor(visitorQueries));
+        assertEquals(3, visitorQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanFirstQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanFirstQueryBuilderTests.java
index bbae35478c6b5..82bb77726b037 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanFirstQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanFirstQueryBuilderTests.java
@@ -34,13 +34,14 @@
 
 import org.apache.lucene.queries.spans.SpanFirstQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.opensearch.index.query.QueryBuilders.spanTermQuery;
 import static org.hamcrest.CoreMatchers.equalTo;
@@ -71,7 +72,7 @@ public void testParseEnd() throws IOException {
             builder.endObject();
             builder.endObject();
 
-            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(Strings.toString(builder)));
+            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(builder.toString()));
             assertTrue(e.getMessage().contains("span_first must have [end] set"));
         }
         {
@@ -82,7 +83,7 @@ public void testParseEnd() throws IOException {
             builder.endObject();
             builder.endObject();
 
-            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(Strings.toString(builder)));
+            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(builder.toString()));
             assertTrue(e.getMessage().contains("span_first must have [match] span query clause"));
         }
     }
@@ -129,4 +130,10 @@ public void testFromJsonWithNonDefaultBoostInMatchQuery() {
         Exception exception = expectThrows(ParsingException.class, () -> parseQuery(json));
         assertThat(exception.getMessage(), equalTo("span_first [match] as a nested span clause can't have non-default boost value [2.0]"));
     }
+
+    public void testVisit() {
+        List<QueryBuilder> visitorQueries = new ArrayList<>();
+        doCreateTestQueryBuilder().visit(createTestVisitor(visitorQueries));
+        assertEquals(2, visitorQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanMultiTermQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanMultiTermQueryBuilderTests.java
index 50f51f9ff68d1..b4abff118802e 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanMultiTermQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanMultiTermQueryBuilderTests.java
@@ -36,7 +36,6 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.SpanMatchNoDocsQuery;
 import org.apache.lucene.queries.spans.FieldMaskingSpanQuery;
@@ -52,15 +51,17 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopTermsRewrite;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.Strings;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lucene.search.SpanBooleanQueryRewriteWithMaxClause;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static java.util.Collections.singleton;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
@@ -92,7 +93,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
             .endObject()
             .endObject();
 
-        mapperService.merge("_doc", new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("_doc", new CompressedXContent(mapping.toString()), MapperService.MergeReason.MAPPING_UPDATE);
     }
 
     @Override
@@ -284,8 +285,9 @@ public void testTermExpansionExceptionOnSpanFailure() throws Exception {
                     BooleanQuery.setMaxClauseCount(1);
                     try {
                         QueryBuilder queryBuilder = new SpanMultiTermQueryBuilder(QueryBuilders.prefixQuery("body", "bar"));
-                        Query query = queryBuilder.toQuery(createShardContext(new IndexSearcher(reader)));
-                        RuntimeException exc = expectThrows(RuntimeException.class, () -> query.rewrite(reader));
+                        IndexSearcher searcher = new IndexSearcher(reader);
+                        Query query = queryBuilder.toQuery(createShardContext(searcher));
+                        RuntimeException exc = expectThrows(RuntimeException.class, () -> query.rewrite(searcher));
                         assertThat(exc.getMessage(), containsString("maxClauseCount"));
                     } finally {
                         BooleanQuery.setMaxClauseCount(origBoolMaxClauseCount);
@@ -306,4 +308,12 @@ public void testTopNMultiTermsRewriteInsideSpan() throws Exception {
         }
 
     }
+
+    public void testVisit() {
+        MultiTermQueryBuilder multiTermQueryBuilder = new PrefixQueryBuilderTests().createTestQueryBuilder();
+        SpanMultiTermQueryBuilder spanMultiTermQueryBuilder = new SpanMultiTermQueryBuilder(multiTermQueryBuilder);
+        List<QueryBuilder> visitorQueries = new ArrayList<>();
+        spanMultiTermQueryBuilder.visit(createTestVisitor(visitorQueries));
+        assertEquals(2, visitorQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanNearQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanNearQueryBuilderTests.java
index 416e37db764b3..c97b541da2199 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanNearQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanNearQueryBuilderTests.java
@@ -37,11 +37,13 @@
 import org.apache.lucene.queries.spans.SpanQuery;
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.either;
@@ -231,4 +233,12 @@ public void testFromJsonWithNonDefaultBoostInInnerQuery() {
         Exception exception = expectThrows(ParsingException.class, () -> parseQuery(json));
         assertThat(exception.getMessage(), equalTo("span_near [clauses] as a nested span clause can't have non-default boost value [2.0]"));
     }
+
+    public void testVisit() {
+        SpanTermQueryBuilder[] spanTermQueries = new SpanTermQueryBuilderTests().createSpanTermQueryBuilders(1);
+        SpanNearQueryBuilder spanNearQueryBuilder = new SpanNearQueryBuilder(spanTermQueries[0], 1);
+        List<QueryBuilder> visitorQueries = new ArrayList<>();
+        spanNearQueryBuilder.visit(createTestVisitor(visitorQueries));
+        assertEquals(2, visitorQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanNotQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanNotQueryBuilderTests.java
index 4222e42af9043..ff42b271ffca5 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanNotQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanNotQueryBuilderTests.java
@@ -34,13 +34,14 @@
 
 import org.apache.lucene.queries.spans.SpanNotQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.opensearch.index.query.QueryBuilders.spanNearQuery;
 import static org.opensearch.index.query.QueryBuilders.spanTermQuery;
@@ -126,7 +127,7 @@ public void testParseDist() throws IOException {
         builder.field("dist", 3);
         builder.endObject();
         builder.endObject();
-        SpanNotQueryBuilder query = (SpanNotQueryBuilder) parseQuery(Strings.toString(builder));
+        SpanNotQueryBuilder query = (SpanNotQueryBuilder) parseQuery(builder.toString());
         assertThat(query.pre(), equalTo(3));
         assertThat(query.post(), equalTo(3));
         assertNotNull(query.includeQuery());
@@ -147,7 +148,7 @@ public void testParserExceptions() throws IOException {
             builder.endObject();
             builder.endObject();
 
-            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(Strings.toString(builder)));
+            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(builder.toString()));
             assertThat(e.getDetailedMessage(), containsString("span_not must have [include]"));
         }
         {
@@ -162,7 +163,7 @@ public void testParserExceptions() throws IOException {
             builder.endObject();
             builder.endObject();
 
-            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(Strings.toString(builder)));
+            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(builder.toString()));
             assertThat(e.getDetailedMessage(), containsString("span_not must have [exclude]"));
         }
         {
@@ -180,7 +181,7 @@ public void testParserExceptions() throws IOException {
             builder.endObject();
             builder.endObject();
 
-            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(Strings.toString(builder)));
+            ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(builder.toString()));
             assertThat(e.getDetailedMessage(), containsString("span_not can either use [dist] or [pre] & [post] (or none)"));
         }
     }
@@ -317,4 +318,10 @@ public void testFromJsonWithNonDefaultBoostInExcludeQuery() {
         Exception exception = expectThrows(ParsingException.class, () -> parseQuery(json));
         assertThat(exception.getMessage(), equalTo("span_not [exclude] as a nested span clause can't have non-default boost value [2.0]"));
     }
+
+    public void testVisit() {
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        doCreateTestQueryBuilder().visit(createTestVisitor(visitedQueries));
+        assertEquals(3, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanOrQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanOrQueryBuilderTests.java
index 45764708efb46..eb4b8fd486cb0 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanOrQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanOrQueryBuilderTests.java
@@ -35,11 +35,13 @@
 import org.apache.lucene.queries.spans.SpanOrQuery;
 import org.apache.lucene.queries.spans.SpanQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -137,4 +139,12 @@ public void testFromJsonWithNonDefaultBoostInInnerQuery() {
         Exception exception = expectThrows(ParsingException.class, () -> parseQuery(json));
         assertThat(exception.getMessage(), equalTo("span_or [clauses] as a nested span clause can't have non-default boost value [2.0]"));
     }
+
+    public void testVisit() {
+        SpanTermQueryBuilder spanTermQueryBuilder = new SpanTermQueryBuilder("demo", "demo");
+        SpanOrQueryBuilder spanOrQueryBuilder = new SpanOrQueryBuilder(spanTermQueryBuilder);
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        spanOrQueryBuilder.visit(createTestVisitor(visitedQueries));
+        assertEquals(2, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/SpanTermQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanTermQueryBuilderTests.java
index 30f2143d74f1d..aa864f620b8b5 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanTermQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanTermQueryBuilderTests.java
@@ -33,12 +33,13 @@
 package org.opensearch.index.query;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
-import org.apache.lucene.queries.spans.SpanTermQuery;
+
 import org.apache.lucene.index.Term;
+import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.lucene.BytesRefs;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/SpanWithinQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/SpanWithinQueryBuilderTests.java
index 25fd137aac286..74b955e872d51 100644
--- a/server/src/test/java/org/opensearch/index/query/SpanWithinQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/SpanWithinQueryBuilderTests.java
@@ -34,10 +34,12 @@
 
 import org.apache.lucene.queries.spans.SpanWithinQuery;
 import org.apache.lucene.search.Query;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -189,4 +191,10 @@ public void testFromJsonWithNonDefaultBoostInLittleQuery() {
             equalTo("span_within [little] as a nested span clause can't have non-default boost value [2.0]")
         );
     }
+
+    public void testVisit() {
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        doCreateTestQueryBuilder().visit(createTestVisitor(visitedQueries));
+        assertEquals(3, visitedQueries.size());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/query/TermQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/TermQueryBuilderTests.java
index 9cac88a256a0a..3ac9bce840a20 100644
--- a/server/src/test/java/org/opensearch/index/query/TermQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/TermQueryBuilderTests.java
@@ -33,15 +33,15 @@
 package org.opensearch.index.query;
 
 import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.AutomatonQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.PointRangeQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.index.mapper.MappedFieldType;
-import org.opensearch.index.mapper.TypeFieldMapper;
 
 import java.io.IOException;
 
@@ -198,12 +198,6 @@ public void testParseAndSerializeBigInteger() throws IOException {
         assertSerialization(parsedQuery);
     }
 
-    public void testTypeField() throws IOException {
-        TermQueryBuilder builder = QueryBuilders.termQuery("_type", "value1");
-        builder.doToQuery(createShardContext());
-        assertWarnings(TypeFieldMapper.TYPES_DEPRECATION_MESSAGE);
-    }
-
     public void testRewriteIndexQueryToMatchNone() throws IOException {
         TermQueryBuilder query = QueryBuilders.termQuery("_index", "does_not_exist");
         QueryShardContext queryShardContext = createShardContext();
diff --git a/server/src/test/java/org/opensearch/index/query/TermsQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/TermsQueryBuilderTests.java
index ea93d7a65b951..32e94b8aa48c6 100644
--- a/server/src/test/java/org/opensearch/index/query/TermsQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/TermsQueryBuilderTests.java
@@ -42,15 +42,13 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResult;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.indices.TermsLookup;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.hamcrest.CoreMatchers;
@@ -235,7 +233,7 @@ public GetResponse executeGet(GetRequest getRequest) {
             builder.startObject();
             builder.array(termsPath, randomTerms.toArray(new Object[randomTerms.size()]));
             builder.endObject();
-            json = Strings.toString(builder);
+            json = builder.toString();
         } catch (IOException ex) {
             throw new OpenSearchException("boom", ex);
         }
@@ -270,9 +268,14 @@ public void testNumeric() throws IOException {
     }
 
     public void testTermsQueryWithMultipleFields() throws IOException {
-        String query = Strings.toString(
-            XContentFactory.jsonBuilder().startObject().startObject("terms").array("foo", 123).array("bar", 456).endObject().endObject()
-        );
+        String query = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("terms")
+            .array("foo", 123)
+            .array("bar", 456)
+            .endObject()
+            .endObject()
+            .toString();
         ParsingException e = expectThrows(ParsingException.class, () -> parseQuery(query));
         assertEquals("[" + TermsQueryBuilder.NAME + "] query does not support multiple fields", e.getMessage());
     }
@@ -351,12 +354,6 @@ public void testConversion() {
         assertEquals(Arrays.asList(5, 42d), TermsQueryBuilder.convertBack(TermsQueryBuilder.convert(list)));
     }
 
-    public void testTypeField() throws IOException {
-        TermsQueryBuilder builder = QueryBuilders.termsQuery("_type", "value1", "value2");
-        builder.doToQuery(createShardContext());
-        assertWarnings(TypeFieldMapper.TYPES_DEPRECATION_MESSAGE);
-    }
-
     public void testRewriteIndexQueryToMatchNone() throws IOException {
         TermsQueryBuilder query = new TermsQueryBuilder("_index", "does_not_exist", "also_does_not_exist");
         QueryShardContext queryShardContext = createShardContext();
diff --git a/server/src/test/java/org/opensearch/index/query/TermsSetQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/TermsSetQueryBuilderTests.java
index 43ca3139e30cb..63ea71458f1e7 100644
--- a/server/src/test/java/org/opensearch/index/query/TermsSetQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/TermsSetQueryBuilderTests.java
@@ -52,7 +52,6 @@
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.mapper.MapperService;
@@ -93,7 +92,7 @@ protected void initializeAdditionalMappings(MapperService mapperService) throws
         String docType = "_doc";
         mapperService.merge(
             docType,
-            new CompressedXContent(Strings.toString(PutMappingRequest.simpleMapping("m_s_m", "type=long"))),
+            new CompressedXContent(PutMappingRequest.simpleMapping("m_s_m", "type=long").toString()),
             MapperService.MergeReason.MAPPING_UPDATE
         );
     }
diff --git a/server/src/test/java/org/opensearch/index/query/WildcardIntervalsSourceProviderTests.java b/server/src/test/java/org/opensearch/index/query/WildcardIntervalsSourceProviderTests.java
index 784159005e1e3..d397cf7db8500 100644
--- a/server/src/test/java/org/opensearch/index/query/WildcardIntervalsSourceProviderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/WildcardIntervalsSourceProviderTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.query;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/query/WildcardQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/WildcardQueryBuilderTests.java
index c8a4207f21c25..f4ec241a64a26 100644
--- a/server/src/test/java/org/opensearch/index/query/WildcardQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/WildcardQueryBuilderTests.java
@@ -35,8 +35,7 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.WildcardQuery;
-import org.opensearch.common.ParsingException;
-import org.opensearch.index.mapper.TypeFieldMapper;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
@@ -150,12 +149,6 @@ public void testParseFailsWithMultipleFields() throws IOException {
         assertEquals("[wildcard] query doesn't support multiple fields, found [user1] and [user2]", e.getMessage());
     }
 
-    public void testTypeField() throws IOException {
-        WildcardQueryBuilder builder = QueryBuilders.wildcardQuery("_type", "doc*");
-        builder.doToQuery(createShardContext());
-        assertWarnings(TypeFieldMapper.TYPES_DEPRECATION_MESSAGE);
-    }
-
     public void testRewriteIndexQueryToMatchNone() throws IOException {
         WildcardQueryBuilder query = new WildcardQueryBuilder("_index", "does_not_exist");
         QueryShardContext queryShardContext = createShardContext();
diff --git a/server/src/test/java/org/opensearch/index/query/WrapperQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/WrapperQueryBuilderTests.java
index 09944b94aca8c..4135f6e0ef049 100644
--- a/server/src/test/java/org/opensearch/index/query/WrapperQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/WrapperQueryBuilderTests.java
@@ -37,11 +37,10 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
@@ -70,7 +69,7 @@ protected WrapperQueryBuilder doCreateTestQueryBuilder() {
         QueryBuilder wrappedQuery = RandomQueryBuilder.createQuery(random());
         BytesReference bytes;
         try {
-            bytes = XContentHelper.toXContent(wrappedQuery, XContentType.JSON, false);
+            bytes = org.opensearch.core.xcontent.XContentHelper.toXContent(wrappedQuery, MediaTypeRegistry.JSON, false);
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
diff --git a/server/src/test/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionModifierTests.java b/server/src/test/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionModifierTests.java
index eac05176e9766..49cdd6de63189 100644
--- a/server/src/test/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionModifierTests.java
+++ b/server/src/test/java/org/opensearch/index/query/functionscore/FieldValueFactorFunctionModifierTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.query.functionscore;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreEquivalenceTests.java b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreEquivalenceTests.java
index a78cccbbc8083..95a92af65fc8b 100644
--- a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreEquivalenceTests.java
+++ b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreEquivalenceTests.java
@@ -34,9 +34,9 @@
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.tests.search.SearchEquivalenceTestBase;
-import org.apache.lucene.search.TermQuery;
 import org.opensearch.bootstrap.BootstrapForTesting;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 
diff --git a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java
index 4f19225faa4c1..4e64a1ec03688 100644
--- a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java
@@ -39,19 +39,19 @@
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.function.CombineFunction;
 import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
 import org.opensearch.common.lucene.search.function.WeightFactorFunction;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
@@ -69,10 +69,10 @@
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
-import org.hamcrest.CoreMatchers;
-import org.hamcrest.Matcher;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.Matcher;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -360,7 +360,7 @@ public void testParseFunctionsArray() throws IOException {
          * given that we copy part of the decay functions as bytes, we test that fromXContent and toXContent both work no matter what the
          * initial format was
          */
-        for (XContentType xContentType : XContentType.values()) {
+        for (MediaType xContentType : XContentType.values()) {
             assertThat(queryBuilder, instanceOf(FunctionScoreQueryBuilder.class));
             FunctionScoreQueryBuilder functionScoreQueryBuilder = (FunctionScoreQueryBuilder) queryBuilder;
             assertThat(functionScoreQueryBuilder.query(), instanceOf(TermQueryBuilder.class));
@@ -521,20 +521,19 @@ public void testProperErrorMessageWhenMissingFunction() throws IOException {
     }
 
     public void testWeight1fStillProducesWeightFunction() throws IOException {
-        String queryString = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("function_score")
-                .startArray("functions")
-                .startObject()
-                .startObject("field_value_factor")
-                .field("field", INT_FIELD_NAME)
-                .endObject()
-                .field("weight", 1.0)
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-        );
+        String queryString = jsonBuilder().startObject()
+            .startObject("function_score")
+            .startArray("functions")
+            .startObject()
+            .startObject("field_value_factor")
+            .field("field", INT_FIELD_NAME)
+            .endObject()
+            .field("weight", 1.0)
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
         QueryBuilder query = parseQuery(queryString);
         assertThat(query, instanceOf(FunctionScoreQueryBuilder.class));
         FunctionScoreQueryBuilder functionScoreQueryBuilder = (FunctionScoreQueryBuilder) query;
@@ -561,36 +560,34 @@ public void testWeight1fStillProducesWeightFunction() throws IOException {
     }
 
     public void testProperErrorMessagesForMisplacedWeightsAndFunctions() throws IOException {
-        String query = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("function_score")
-                .startArray("functions")
-                .startObject()
-                .startObject("script_score")
-                .field("script", "3")
-                .endObject()
-                .endObject()
-                .endArray()
-                .field("weight", 2)
-                .endObject()
-                .endObject()
-        );
+        String query = jsonBuilder().startObject()
+            .startObject("function_score")
+            .startArray("functions")
+            .startObject()
+            .startObject("script_score")
+            .field("script", "3")
+            .endObject()
+            .endObject()
+            .endArray()
+            .field("weight", 2)
+            .endObject()
+            .endObject()
+            .toString();
         expectParsingException(
             query,
             "[you can either define [functions] array or a single function, not both. already "
                 + "found [functions] array, now encountering [weight].]"
         );
-        query = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("function_score")
-                .field("weight", 2)
-                .startArray("functions")
-                .startObject()
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-        );
+        query = jsonBuilder().startObject()
+            .startObject("function_score")
+            .field("weight", 2)
+            .startArray("functions")
+            .startObject()
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .toString();
         expectParsingException(
             query,
             "[you can either define [functions] array or a single function, not both. already found "
diff --git a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreTests.java b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreTests.java
index 3bcda9f5e762f..0ea91efc568d0 100644
--- a/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreTests.java
+++ b/server/src/test/java/org/opensearch/index/query/functionscore/FunctionScoreTests.java
@@ -45,13 +45,13 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
diff --git a/server/src/test/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilderTests.java b/server/src/test/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilderTests.java
index 9badef6af8b04..db51bc89b041f 100644
--- a/server/src/test/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilderTests.java
+++ b/server/src/test/java/org/opensearch/index/query/functionscore/ScoreFunctionBuilderTests.java
@@ -43,6 +43,7 @@
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.script.Script;
 import org.opensearch.test.OpenSearchTestCase;
+
 import org.mockito.Mockito;
 
 public class ScoreFunctionBuilderTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/index/query/plugin/DummyQueryBuilder.java b/server/src/test/java/org/opensearch/index/query/plugin/DummyQueryBuilder.java
index b6a470fac4639..2b0aaa2dd7091 100644
--- a/server/src/test/java/org/opensearch/index/query/plugin/DummyQueryBuilder.java
+++ b/server/src/test/java/org/opensearch/index/query/plugin/DummyQueryBuilder.java
@@ -33,10 +33,10 @@
 package org.opensearch.index.query.plugin;
 
 import org.apache.lucene.search.Query;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.plugin.DummyQueryParserPlugin.DummyQuery;
diff --git a/server/src/test/java/org/opensearch/index/refresh/RefreshStatsTests.java b/server/src/test/java/org/opensearch/index/refresh/RefreshStatsTests.java
index 6b04e0ab43d8c..3a1239a21c889 100644
--- a/server/src/test/java/org/opensearch/index/refresh/RefreshStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/refresh/RefreshStatsTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.refresh;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestTestCase.java b/server/src/test/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestTestCase.java
index 6db3c9e779af3..1d22d9c19cf05 100644
--- a/server/src/test/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestTestCase.java
+++ b/server/src/test/java/org/opensearch/index/reindex/AbstractBulkByScrollRequestTestCase.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.ActiveShardCount;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.test.AbstractXContentTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollResponseTests.java b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollResponseTests.java
index f9101ee8a50c1..1d4c3c57f73bb 100644
--- a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollResponseTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollResponseTests.java
@@ -38,9 +38,9 @@
 import org.opensearch.action.bulk.BulkItemResponse.Failure;
 import org.opensearch.client.transport.NoNodeAvailableException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.reindex.BulkByScrollTask.Status;
 import org.opensearch.test.AbstractXContentTestCase;
 
@@ -51,8 +51,8 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class BulkByScrollResponseTests extends AbstractXContentTestCase<BulkByScrollResponse> {
 
diff --git a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusOrExceptionTests.java b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusOrExceptionTests.java
index f279c5354b016..ee9b422aa8178 100644
--- a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusOrExceptionTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusOrExceptionTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.test.AbstractXContentTestCase;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.reindex.BulkByScrollTask.StatusOrException;
+import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
 import java.util.function.Supplier;
diff --git a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusTests.java b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusTests.java
index bd8acb8bc18b7..4942d31f4ca53 100644
--- a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskStatusTests.java
@@ -36,14 +36,14 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.reindex.BulkByScrollTask.Status;
 import org.opensearch.test.AbstractXContentTestCase;
 import org.hamcrest.Matchers;
-import org.opensearch.index.reindex.BulkByScrollTask.Status;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -55,8 +55,8 @@
 
 import static java.lang.Math.abs;
 import static java.util.stream.Collectors.toList;
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class BulkByScrollTaskStatusTests extends AbstractXContentTestCase<BulkByScrollTask.Status> {
 
diff --git a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskTests.java b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskTests.java
index 682bbc6256c6e..c66d858fff2b4 100644
--- a/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/BulkByScrollTaskTests.java
@@ -32,11 +32,10 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -122,7 +121,7 @@ public void testXContentRepresentationOfUnlimitedRequestsPerSecond() throws IOEx
             timeValueMillis(0)
         );
         status.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertThat(Strings.toString(builder), containsString("\"requests_per_second\":-1"));
+        assertThat(builder.toString(), containsString("\"requests_per_second\":-1"));
     }
 
     public void testXContentRepresentationOfUnfinishedSlices() throws IOException {
@@ -148,7 +147,7 @@ public void testXContentRepresentationOfUnfinishedSlices() throws IOException {
             null
         );
         status.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertThat(Strings.toString(builder), containsString("\"slices\":[null,null,{\"slice_id\":2"));
+        assertThat(builder.toString(), containsString("\"slices\":[null,null,{\"slice_id\":2"));
     }
 
     public void testXContentRepresentationOfSliceFailures() throws IOException {
@@ -159,7 +158,7 @@ public void testXContentRepresentationOfSliceFailures() throws IOException {
             null
         );
         status.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertThat(Strings.toString(builder), containsString("\"slices\":[null,null,{\"type\":\"exception\""));
+        assertThat(builder.toString(), containsString("\"slices\":[null,null,{\"type\":\"exception\""));
     }
 
     public void testMergeStatuses() {
diff --git a/server/src/test/java/org/opensearch/index/reindex/DeleteByQueryRequestTests.java b/server/src/test/java/org/opensearch/index/reindex/DeleteByQueryRequestTests.java
index 747ce00134adc..eec60bec23a98 100644
--- a/server/src/test/java/org/opensearch/index/reindex/DeleteByQueryRequestTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/DeleteByQueryRequestTests.java
@@ -35,16 +35,16 @@
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilders;
 
 import java.io.IOException;
 
-import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
+import static org.apache.lucene.tests.util.TestUtil.randomSimpleString;
 
 public class DeleteByQueryRequestTests extends AbstractBulkByScrollRequestTestCase<DeleteByQueryRequest> {
     public void testDeleteteByQueryRequestImplementsIndicesRequestReplaceable() {
diff --git a/server/src/test/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskStateTests.java b/server/src/test/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskStateTests.java
index d24f720273586..5dcf429085f45 100644
--- a/server/src/test/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskStateTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/LeaderBulkByScrollTaskStateTests.java
@@ -32,16 +32,17 @@
 
 package org.opensearch.index.reindex;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
-import org.mockito.ArgumentCaptor;
 
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import org.mockito.ArgumentCaptor;
+
 import static java.util.Collections.emptyList;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.mockito.Mockito.atMost;
diff --git a/server/src/test/java/org/opensearch/index/reindex/ReindexRequestTests.java b/server/src/test/java/org/opensearch/index/reindex/ReindexRequestTests.java
index 6fe277ad2751b..fa8f9a2e99e1e 100644
--- a/server/src/test/java/org/opensearch/index/reindex/ReindexRequestTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/ReindexRequestTests.java
@@ -33,15 +33,15 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.TermQueryBuilder;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.slice.SliceBuilder;
diff --git a/server/src/test/java/org/opensearch/index/reindex/UpdateByQueryRequestTests.java b/server/src/test/java/org/opensearch/index/reindex/UpdateByQueryRequestTests.java
index 4cdb94897d4dc..5fdcb00cdda5f 100644
--- a/server/src/test/java/org/opensearch/index/reindex/UpdateByQueryRequestTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/UpdateByQueryRequestTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskStateTests.java b/server/src/test/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskStateTests.java
index 1724f552da845..08ca8fd3ced90 100644
--- a/server/src/test/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskStateTests.java
+++ b/server/src/test/java/org/opensearch/index/reindex/WorkerBulkByScrollTaskStateTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteSegmentTransferTrackerTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteSegmentTransferTrackerTests.java
new file mode 100644
index 0000000000000..0bf00f9e48137
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteSegmentTransferTrackerTests.java
@@ -0,0 +1,603 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.store.DirectoryFileTransferTracker;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class RemoteSegmentTransferTrackerTests extends OpenSearchTestCase {
+    private RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+    private ClusterService clusterService;
+
+    private ThreadPool threadPool;
+
+    private ShardId shardId;
+
+    private RemoteSegmentTransferTracker transferTracker;
+
+    private DirectoryFileTransferTracker directoryFileTransferTracker;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("remote_refresh_segment_pressure_settings_test");
+        clusterService = new ClusterService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, Settings.EMPTY);
+        shardId = new ShardId("index", "uuid", 0);
+        directoryFileTransferTracker = new DirectoryFileTransferTracker();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testGetShardId() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        assertEquals(shardId, transferTracker.getShardId());
+    }
+
+    public void testUpdateLocalRefreshSeqNo() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long refreshSeqNo = 2;
+        transferTracker.updateLocalRefreshSeqNo(refreshSeqNo);
+        assertEquals(refreshSeqNo, transferTracker.getLocalRefreshSeqNo());
+    }
+
+    public void testUpdateRemoteRefreshSeqNo() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long refreshSeqNo = 4;
+        transferTracker.updateRemoteRefreshSeqNo(refreshSeqNo);
+        assertEquals(refreshSeqNo, transferTracker.getRemoteRefreshSeqNo());
+    }
+
+    public void testUpdateLocalRefreshTimeMs() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long refreshTimeMs = System.nanoTime() / 1_000_000L + randomIntBetween(10, 100);
+        transferTracker.updateLocalRefreshTimeMs(refreshTimeMs);
+        assertEquals(refreshTimeMs, transferTracker.getLocalRefreshTimeMs());
+    }
+
+    public void testUpdateRemoteRefreshTimeMs() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long refreshTimeMs = System.nanoTime() / 1_000_000 + randomIntBetween(10, 100);
+        transferTracker.updateRemoteRefreshTimeMs(refreshTimeMs);
+        assertEquals(refreshTimeMs, transferTracker.getRemoteRefreshTimeMs());
+    }
+
+    public void testLastDownloadTimestampMs() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long currentTimeInMs = System.currentTimeMillis();
+        transferTracker.getDirectoryFileTransferTracker().updateLastTransferTimestampMs(currentTimeInMs);
+        assertEquals(currentTimeInMs, transferTracker.getDirectoryFileTransferTracker().getLastTransferTimestampMs());
+    }
+
+    public void testComputeSeqNoLagOnUpdate() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        int localRefreshSeqNo = randomIntBetween(50, 100);
+        int remoteRefreshSeqNo = randomIntBetween(20, 50);
+        transferTracker.updateLocalRefreshSeqNo(localRefreshSeqNo);
+        assertEquals(localRefreshSeqNo, transferTracker.getRefreshSeqNoLag());
+        transferTracker.updateRemoteRefreshSeqNo(remoteRefreshSeqNo);
+        assertEquals(localRefreshSeqNo - remoteRefreshSeqNo, transferTracker.getRefreshSeqNoLag());
+    }
+
+    public void testComputeTimeLagOnUpdate() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long currentLocalRefreshTimeMs = transferTracker.getLocalRefreshTimeMs();
+        long currentTimeMs = System.nanoTime() / 1_000_000L;
+        long localRefreshTimeMs = currentTimeMs + randomIntBetween(100, 500);
+        long remoteRefreshTimeMs = currentTimeMs + randomIntBetween(50, 99);
+        transferTracker.updateLocalRefreshTimeMs(localRefreshTimeMs);
+        assertEquals(localRefreshTimeMs - currentLocalRefreshTimeMs, transferTracker.getTimeMsLag());
+        transferTracker.updateRemoteRefreshTimeMs(remoteRefreshTimeMs);
+        assertEquals(localRefreshTimeMs - remoteRefreshTimeMs, transferTracker.getTimeMsLag());
+    }
+
+    public void testAddUploadBytesStarted() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        transferTracker.addUploadBytesStarted(bytesToAdd);
+        assertEquals(bytesToAdd, transferTracker.getUploadBytesStarted());
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.addUploadBytesStarted(moreBytesToAdd);
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getUploadBytesStarted());
+    }
+
+    public void testAddUploadBytesFailed() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.addUploadBytesStarted(bytesToAdd + moreBytesToAdd);
+        transferTracker.addUploadBytesFailed(bytesToAdd);
+        assertEquals(bytesToAdd, transferTracker.getUploadBytesFailed());
+        transferTracker.addUploadBytesFailed(moreBytesToAdd);
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getUploadBytesFailed());
+    }
+
+    public void testAddUploadBytesSucceeded() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.addUploadBytesStarted(bytesToAdd + moreBytesToAdd);
+        transferTracker.addUploadBytesSucceeded(bytesToAdd);
+        assertEquals(bytesToAdd, transferTracker.getUploadBytesSucceeded());
+        transferTracker.addUploadBytesSucceeded(moreBytesToAdd);
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getUploadBytesSucceeded());
+    }
+
+    public void testAddDownloadBytesStarted() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesStarted(bytesToAdd);
+        assertEquals(bytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesStarted());
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesStarted(moreBytesToAdd);
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesStarted());
+    }
+
+    public void testAddDownloadBytesFailed() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesFailed(bytesToAdd, System.currentTimeMillis());
+        assertEquals(bytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesFailed());
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesFailed(moreBytesToAdd, System.currentTimeMillis());
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesFailed());
+    }
+
+    public void testAddDownloadBytesSucceeded() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesToAdd = randomLongBetween(1000, 1000000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesSucceeded(bytesToAdd, System.currentTimeMillis());
+        assertEquals(bytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesSucceeded());
+        long moreBytesToAdd = randomLongBetween(1000, 10000);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesSucceeded(moreBytesToAdd, System.currentTimeMillis());
+        assertEquals(bytesToAdd + moreBytesToAdd, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesSucceeded());
+    }
+
+    public void testGetInflightUploadBytes() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long bytesStarted = randomLongBetween(10000, 100000);
+        long bytesSucceeded = randomLongBetween(1000, 10000);
+        long bytesFailed = randomLongBetween(100, 1000);
+        transferTracker.addUploadBytesStarted(bytesStarted);
+        transferTracker.addUploadBytesSucceeded(bytesSucceeded);
+        transferTracker.addUploadBytesFailed(bytesFailed);
+        assertEquals(bytesStarted - bytesSucceeded - bytesFailed, transferTracker.getInflightUploadBytes());
+    }
+
+    public void testIncrementTotalUploadsStarted() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        assertEquals(1, transferTracker.getTotalUploadsStarted());
+        transferTracker.incrementTotalUploadsStarted();
+        assertEquals(2, transferTracker.getTotalUploadsStarted());
+    }
+
+    public void testIncrementTotalUploadsFailed() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsFailed();
+        assertEquals(1, transferTracker.getTotalUploadsFailed());
+        transferTracker.incrementTotalUploadsFailed();
+        assertEquals(2, transferTracker.getTotalUploadsFailed());
+    }
+
+    public void testIncrementTotalUploadSucceeded() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsSucceeded();
+        assertEquals(1, transferTracker.getTotalUploadsSucceeded());
+        transferTracker.incrementTotalUploadsSucceeded();
+        assertEquals(2, transferTracker.getTotalUploadsSucceeded());
+    }
+
+    public void testGetInflightUploads() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        assertEquals(1, transferTracker.getInflightUploads());
+        transferTracker.incrementTotalUploadsStarted();
+        assertEquals(2, transferTracker.getInflightUploads());
+        transferTracker.incrementTotalUploadsSucceeded();
+        assertEquals(1, transferTracker.getInflightUploads());
+        transferTracker.incrementTotalUploadsFailed();
+        assertEquals(0, transferTracker.getInflightUploads());
+    }
+
+    public void testIncrementRejectionCount() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementRejectionCount();
+        assertEquals(1, transferTracker.getRejectionCount());
+        transferTracker.incrementRejectionCount();
+        assertEquals(2, transferTracker.getRejectionCount());
+    }
+
+    public void testGetConsecutiveFailureCount() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsFailed();
+        assertEquals(1, transferTracker.getConsecutiveFailureCount());
+        transferTracker.incrementTotalUploadsFailed();
+        assertEquals(2, transferTracker.getConsecutiveFailureCount());
+        transferTracker.incrementTotalUploadsSucceeded();
+        assertEquals(0, transferTracker.getConsecutiveFailureCount());
+    }
+
+    public void testComputeBytesLag() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+
+        // Create local file size map
+        Map<String, Long> fileSizeMap = new HashMap<>();
+        fileSizeMap.put("a", 100L);
+        fileSizeMap.put("b", 105L);
+        transferTracker.updateLatestLocalFileNameLengthMap(fileSizeMap.keySet(), fileSizeMap::get);
+        assertEquals(205L, transferTracker.getBytesLag());
+
+        transferTracker.addToLatestUploadedFiles("a");
+        assertEquals(105L, transferTracker.getBytesLag());
+
+        fileSizeMap.put("c", 115L);
+        transferTracker.updateLatestLocalFileNameLengthMap(fileSizeMap.keySet(), fileSizeMap::get);
+        assertEquals(220L, transferTracker.getBytesLag());
+
+        transferTracker.addToLatestUploadedFiles("b");
+        assertEquals(115L, transferTracker.getBytesLag());
+
+        transferTracker.addToLatestUploadedFiles("c");
+        assertEquals(0L, transferTracker.getBytesLag());
+    }
+
+    public void testisUploadBytesMovingAverageReady() {
+        int movingAverageWindowSize = remoteStoreStatsTrackerFactory.getMovingAverageWindowSize();
+        transferTracker = new RemoteSegmentTransferTracker(shardId, directoryFileTransferTracker, movingAverageWindowSize);
+        assertFalse(transferTracker.isUploadBytesMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            transferTracker.updateUploadBytesMovingAverage(i);
+            sum += i;
+            assertFalse(transferTracker.isUploadBytesMovingAverageReady());
+            assertEquals((double) sum / i, transferTracker.getUploadBytesMovingAverage(), 0.0d);
+        }
+
+        transferTracker.updateUploadBytesMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(transferTracker.isUploadBytesMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadBytesMovingAverage(), 0.0d);
+
+        transferTracker.updateUploadBytesMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadBytesMovingAverage(), 0.0d);
+    }
+
+    public void testIsUploadBytesPerSecAverageReady() {
+        int movingAverageWindowSize = remoteStoreStatsTrackerFactory.getMovingAverageWindowSize();
+        transferTracker = new RemoteSegmentTransferTracker(shardId, directoryFileTransferTracker, movingAverageWindowSize);
+        assertFalse(transferTracker.isUploadBytesPerSecMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            transferTracker.updateUploadBytesPerSecMovingAverage(i);
+            sum += i;
+            assertFalse(transferTracker.isUploadBytesPerSecMovingAverageReady());
+            assertEquals((double) sum / i, transferTracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+        }
+
+        transferTracker.updateUploadBytesPerSecMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(transferTracker.isUploadBytesPerSecMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+
+        transferTracker.updateUploadBytesPerSecMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+    }
+
+    public void testIsUploadTimeMsAverageReady() {
+        int movingAverageWindowSize = remoteStoreStatsTrackerFactory.getMovingAverageWindowSize();
+        transferTracker = new RemoteSegmentTransferTracker(shardId, directoryFileTransferTracker, movingAverageWindowSize);
+        assertFalse(transferTracker.isUploadTimeMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            transferTracker.updateUploadTimeMovingAverage(i);
+            sum += i;
+            assertFalse(transferTracker.isUploadTimeMovingAverageReady());
+            assertEquals((double) sum / i, transferTracker.getUploadTimeMovingAverage(), 0.0d);
+        }
+
+        transferTracker.updateUploadTimeMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(transferTracker.isUploadTimeMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadTimeMovingAverage(), 0.0d);
+
+        transferTracker.updateUploadTimeMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, transferTracker.getUploadTimeMovingAverage(), 0.0d);
+    }
+
+    public void testIsDownloadBytesAverageReady() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        assertFalse(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < 20; i++) {
+            transferTracker.getDirectoryFileTransferTracker().updateSuccessfulTransferSize(i);
+            sum += i;
+            assertFalse(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesAverageReady());
+            assertEquals((double) sum / i, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesAverage(), 0.0d);
+        }
+
+        transferTracker.getDirectoryFileTransferTracker().updateSuccessfulTransferSize(20);
+        sum += 20;
+        assertTrue(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesAverageReady());
+        assertEquals((double) sum / 20, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesAverage(), 0.0d);
+
+        transferTracker.getDirectoryFileTransferTracker().updateSuccessfulTransferSize(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / 20, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesAverage(), 0.0d);
+    }
+
+    public void testIsDownloadBytesPerSecAverageReady() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        assertFalse(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesPerSecAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < 20; i++) {
+            transferTracker.getDirectoryFileTransferTracker().addTransferredBytesPerSec(i);
+            sum += i;
+            assertFalse(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesPerSecAverageReady());
+            assertEquals((double) sum / i, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesPerSecAverage(), 0.0d);
+        }
+
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesPerSec(20);
+        sum += 20;
+        assertTrue(transferTracker.getDirectoryFileTransferTracker().isTransferredBytesPerSecAverageReady());
+        assertEquals((double) sum / 20, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesPerSecAverage(), 0.0d);
+
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesPerSec(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / 20, transferTracker.getDirectoryFileTransferTracker().getTransferredBytesPerSecAverage(), 0.0d);
+    }
+
+    public void testAddTotalUploadTimeInMs() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long timeToAdd = randomLongBetween(100, 200);
+        transferTracker.addUploadTimeInMillis(timeToAdd);
+        assertEquals(timeToAdd, transferTracker.getTotalUploadTimeInMillis());
+        long moreTimeToAdd = randomLongBetween(100, 200);
+        transferTracker.addUploadTimeInMillis(moreTimeToAdd);
+        assertEquals(timeToAdd + moreTimeToAdd, transferTracker.getTotalUploadTimeInMillis());
+    }
+
+    public void testAddTotalTransferTimeMs() {
+        transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            directoryFileTransferTracker,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        long timeToAdd = randomLongBetween(100, 200);
+        transferTracker.getDirectoryFileTransferTracker().addTotalTransferTimeInMs(timeToAdd);
+        assertEquals(timeToAdd, transferTracker.getDirectoryFileTransferTracker().getTotalTransferTimeInMs());
+        long moreTimeToAdd = randomLongBetween(100, 200);
+        transferTracker.getDirectoryFileTransferTracker().addTotalTransferTimeInMs(moreTimeToAdd);
+        assertEquals(timeToAdd + moreTimeToAdd, transferTracker.getDirectoryFileTransferTracker().getTotalTransferTimeInMs());
+    }
+
+    /**
+     * Tests whether RemoteSegmentTransferTracker.Stats object generated correctly from RemoteSegmentTransferTracker.
+     * */
+    public void testStatsObjectCreation() {
+        transferTracker = constructTracker();
+        RemoteSegmentTransferTracker.Stats transferTrackerStats = transferTracker.stats();
+        assertEquals(transferTracker.getShardId(), transferTrackerStats.shardId);
+        assertEquals(transferTracker.getTimeMsLag(), (int) transferTrackerStats.refreshTimeLagMs);
+        assertEquals(transferTracker.getLocalRefreshSeqNo(), (int) transferTrackerStats.localRefreshNumber);
+        assertEquals(transferTracker.getRemoteRefreshSeqNo(), (int) transferTrackerStats.remoteRefreshNumber);
+        assertEquals(transferTracker.getBytesLag(), (int) transferTrackerStats.bytesLag);
+        assertEquals(transferTracker.getRejectionCount(), (int) transferTrackerStats.rejectionCount);
+        assertEquals(transferTracker.getConsecutiveFailureCount(), (int) transferTrackerStats.consecutiveFailuresCount);
+        assertEquals(transferTracker.getUploadBytesStarted(), (int) transferTrackerStats.uploadBytesStarted);
+        assertEquals(transferTracker.getUploadBytesSucceeded(), (int) transferTrackerStats.uploadBytesSucceeded);
+        assertEquals(transferTracker.getUploadBytesFailed(), (int) transferTrackerStats.uploadBytesFailed);
+        assertEquals(transferTracker.getUploadBytesMovingAverage(), transferTrackerStats.uploadBytesMovingAverage, 0);
+        assertEquals(transferTracker.getUploadBytesPerSecMovingAverage(), transferTrackerStats.uploadBytesPerSecMovingAverage, 0);
+        assertEquals(transferTracker.getUploadTimeMovingAverage(), transferTrackerStats.uploadTimeMovingAverage, 0);
+        assertEquals(transferTracker.getTotalUploadsStarted(), (int) transferTrackerStats.totalUploadsStarted);
+        assertEquals(transferTracker.getTotalUploadsSucceeded(), (int) transferTrackerStats.totalUploadsSucceeded);
+        assertEquals(transferTracker.getTotalUploadsFailed(), (int) transferTrackerStats.totalUploadsFailed);
+    }
+
+    /**
+     * Tests whether RemoteSegmentTransferTracker.Stats object serialize and deserialize is working fine.
+     * This comes into play during internode data transfer.
+     */
+    public void testStatsObjectCreationViaStream() throws IOException {
+        transferTracker = constructTracker();
+        RemoteSegmentTransferTracker.Stats transferTrackerStats = transferTracker.stats();
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            transferTrackerStats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteSegmentTransferTracker.Stats deserializedStats = new RemoteSegmentTransferTracker.Stats(in);
+                assertEquals(deserializedStats.shardId, transferTrackerStats.shardId);
+                assertEquals((int) deserializedStats.refreshTimeLagMs, (int) transferTrackerStats.refreshTimeLagMs);
+                assertEquals((int) deserializedStats.localRefreshNumber, (int) transferTrackerStats.localRefreshNumber);
+                assertEquals((int) deserializedStats.remoteRefreshNumber, (int) transferTrackerStats.remoteRefreshNumber);
+                assertEquals((int) deserializedStats.bytesLag, (int) transferTrackerStats.bytesLag);
+                assertEquals((int) deserializedStats.rejectionCount, (int) transferTrackerStats.rejectionCount);
+                assertEquals((int) deserializedStats.consecutiveFailuresCount, (int) transferTrackerStats.consecutiveFailuresCount);
+                assertEquals((int) deserializedStats.uploadBytesStarted, (int) transferTrackerStats.uploadBytesStarted);
+                assertEquals((int) deserializedStats.uploadBytesSucceeded, (int) transferTrackerStats.uploadBytesSucceeded);
+                assertEquals((int) deserializedStats.uploadBytesFailed, (int) transferTrackerStats.uploadBytesFailed);
+                assertEquals((int) deserializedStats.uploadBytesMovingAverage, transferTrackerStats.uploadBytesMovingAverage, 0);
+                assertEquals(
+                    (int) deserializedStats.uploadBytesPerSecMovingAverage,
+                    transferTrackerStats.uploadBytesPerSecMovingAverage,
+                    0
+                );
+                assertEquals((int) deserializedStats.uploadTimeMovingAverage, transferTrackerStats.uploadTimeMovingAverage, 0);
+                assertEquals((int) deserializedStats.totalUploadsStarted, (int) transferTrackerStats.totalUploadsStarted);
+                assertEquals((int) deserializedStats.totalUploadsSucceeded, (int) transferTrackerStats.totalUploadsSucceeded);
+                assertEquals((int) deserializedStats.totalUploadsFailed, (int) transferTrackerStats.totalUploadsFailed);
+                assertEquals(
+                    (int) deserializedStats.directoryFileTransferTrackerStats.transferredBytesStarted,
+                    (int) transferTrackerStats.directoryFileTransferTrackerStats.transferredBytesStarted
+                );
+                assertEquals(
+                    (int) deserializedStats.directoryFileTransferTrackerStats.transferredBytesSucceeded,
+                    (int) transferTrackerStats.directoryFileTransferTrackerStats.transferredBytesSucceeded
+                );
+                assertEquals(
+                    (int) deserializedStats.directoryFileTransferTrackerStats.transferredBytesPerSecMovingAverage,
+                    (int) transferTrackerStats.directoryFileTransferTrackerStats.transferredBytesPerSecMovingAverage
+                );
+            }
+        }
+    }
+
+    private RemoteSegmentTransferTracker constructTracker() {
+        RemoteSegmentTransferTracker transferTracker = new RemoteSegmentTransferTracker(
+            shardId,
+            new DirectoryFileTransferTracker(),
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+        transferTracker.incrementTotalUploadsStarted();
+        transferTracker.incrementTotalUploadsFailed();
+        transferTracker.updateUploadTimeMovingAverage(System.nanoTime() / 1_000_000L + randomIntBetween(10, 100));
+        transferTracker.updateUploadBytesMovingAverage(99);
+        transferTracker.updateRemoteRefreshTimeMs(System.nanoTime() / 1_000_000L + randomIntBetween(10, 100));
+        transferTracker.incrementRejectionCount();
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesStarted(10);
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesSucceeded(10, System.currentTimeMillis());
+        transferTracker.getDirectoryFileTransferTracker().addTransferredBytesPerSec(5);
+        return transferTracker;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureServiceTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureServiceTests.java
new file mode 100644
index 0000000000000..de610083f3327
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureServiceTests.java
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.IntStream;
+
+import static org.opensearch.index.remote.RemoteStoreTestsHelper.createIndexShard;
+
+public class RemoteStorePressureServiceTests extends OpenSearchTestCase {
+
+    private ClusterService clusterService;
+
+    private ThreadPool threadPool;
+
+    private ShardId shardId;
+
+    private RemoteStorePressureService pressureService;
+
+    private RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("remote_refresh_segment_pressure_settings_test");
+        clusterService = new ClusterService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+        shardId = new ShardId("index", "uuid", 0);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testIsSegmentsUploadBackpressureEnabled() {
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, Settings.EMPTY);
+        pressureService = new RemoteStorePressureService(clusterService, Settings.EMPTY, remoteStoreStatsTrackerFactory);
+        assertTrue(pressureService.isSegmentsUploadBackpressureEnabled());
+
+        Settings newSettings = Settings.builder()
+            .put(RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), "true")
+            .build();
+        clusterService.getClusterSettings().applySettings(newSettings);
+
+        assertTrue(pressureService.isSegmentsUploadBackpressureEnabled());
+    }
+
+    public void testValidateSegmentUploadLag() {
+        // Create the pressure tracker
+        IndexShard indexShard = createIndexShard(shardId, true);
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, Settings.EMPTY);
+        pressureService = new RemoteStorePressureService(clusterService, Settings.EMPTY, remoteStoreStatsTrackerFactory);
+        remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+
+        RemoteSegmentTransferTracker pressureTracker = remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId);
+        pressureTracker.updateLocalRefreshSeqNo(6);
+
+        // 1. time lag more than dynamic threshold
+        pressureTracker.updateRemoteRefreshSeqNo(3);
+        AtomicLong sum = new AtomicLong();
+        IntStream.range(0, 20).forEach(i -> {
+            pressureTracker.updateUploadTimeMovingAverage(i);
+            sum.addAndGet(i);
+        });
+        double avg = (double) sum.get() / 20;
+        long currentMs = System.nanoTime() / 1_000_000;
+        pressureTracker.updateLocalRefreshTimeMs((long) (currentMs + 12 * avg));
+        pressureTracker.updateRemoteRefreshTimeMs(currentMs);
+        Exception e = assertThrows(OpenSearchRejectedExecutionException.class, () -> pressureService.validateSegmentsUploadLag(shardId));
+        assertTrue(e.getMessage().contains("due to remote segments lagging behind local segments"));
+        assertTrue(e.getMessage().contains("time_lag:114 ms dynamic_time_lag_threshold:95.0 ms"));
+
+        pressureTracker.updateRemoteRefreshTimeMs((long) (currentMs + 2 * avg));
+        pressureService.validateSegmentsUploadLag(shardId);
+
+        // 2. bytes lag more than dynamic threshold
+        sum.set(0);
+        IntStream.range(0, 20).forEach(i -> {
+            pressureTracker.updateUploadBytesMovingAverage(i);
+            sum.addAndGet(i);
+        });
+        avg = (double) sum.get() / 20;
+        Map<String, Long> nameSizeMap = new HashMap<>();
+        nameSizeMap.put("a", (long) (12 * avg));
+        pressureTracker.updateLatestLocalFileNameLengthMap(nameSizeMap.keySet(), nameSizeMap::get);
+        e = assertThrows(OpenSearchRejectedExecutionException.class, () -> pressureService.validateSegmentsUploadLag(shardId));
+        assertTrue(e.getMessage().contains("due to remote segments lagging behind local segments"));
+        assertTrue(e.getMessage().contains("bytes_lag:114 dynamic_bytes_lag_threshold:95.0"));
+
+        nameSizeMap.clear();
+        nameSizeMap.put("b", (long) (2 * avg));
+        pressureTracker.updateLatestLocalFileNameLengthMap(nameSizeMap.keySet(), nameSizeMap::get);
+        pressureService.validateSegmentsUploadLag(shardId);
+
+        // 3. Consecutive failures more than the limit
+        IntStream.range(0, 5).forEach(ignore -> pressureTracker.incrementTotalUploadsStarted());
+        IntStream.range(0, 5).forEach(ignore -> pressureTracker.incrementTotalUploadsFailed());
+        pressureService.validateSegmentsUploadLag(shardId);
+        pressureTracker.incrementTotalUploadsStarted();
+        pressureTracker.incrementTotalUploadsFailed();
+        e = assertThrows(OpenSearchRejectedExecutionException.class, () -> pressureService.validateSegmentsUploadLag(shardId));
+        assertTrue(e.getMessage().contains("due to remote segments lagging behind local segments"));
+        assertTrue(e.getMessage().contains("failure_streak_count:6 min_consecutive_failure_threshold:5"));
+        pressureTracker.incrementTotalUploadsStarted();
+        pressureTracker.incrementTotalUploadsSucceeded();
+        pressureService.validateSegmentsUploadLag(shardId);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureSettingsTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureSettingsTests.java
new file mode 100644
index 0000000000000..064c6c10eba02
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStorePressureSettingsTests.java
@@ -0,0 +1,150 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import static org.mockito.Mockito.mock;
+
+public class RemoteStorePressureSettingsTests extends OpenSearchTestCase {
+
+    private ClusterService clusterService;
+
+    private ThreadPool threadPool;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool("remote_refresh_segment_pressure_settings_test");
+        clusterService = new ClusterService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testGetDefaultSettings() {
+        RemoteStorePressureSettings pressureSettings = new RemoteStorePressureSettings(
+            clusterService,
+            Settings.EMPTY,
+            mock(RemoteStorePressureService.class)
+        );
+
+        // Check remote refresh segment pressure enabled is false
+        assertTrue(pressureSettings.isRemoteRefreshSegmentPressureEnabled());
+
+        // Check bytes lag variance threshold default value
+        assertEquals(10.0, pressureSettings.getBytesLagVarianceFactor(), 0.0d);
+
+        // Check time lag variance threshold default value
+        assertEquals(10.0, pressureSettings.getUploadTimeLagVarianceFactor(), 0.0d);
+
+        // Check minimum consecutive failures limit default value
+        assertEquals(5, pressureSettings.getMinConsecutiveFailuresLimit());
+    }
+
+    public void testGetConfiguredSettings() {
+        Settings settings = Settings.builder()
+            .put(RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), true)
+            .put(RemoteStorePressureSettings.BYTES_LAG_VARIANCE_FACTOR.getKey(), 50.0)
+            .put(RemoteStorePressureSettings.UPLOAD_TIME_LAG_VARIANCE_FACTOR.getKey(), 60.0)
+            .put(RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT.getKey(), 121)
+            .build();
+        RemoteStorePressureSettings pressureSettings = new RemoteStorePressureSettings(
+            clusterService,
+            settings,
+            mock(RemoteStorePressureService.class)
+        );
+
+        // Check remote refresh segment pressure enabled is true
+        assertTrue(pressureSettings.isRemoteRefreshSegmentPressureEnabled());
+
+        // Check bytes lag variance threshold configured value
+        assertEquals(50.0, pressureSettings.getBytesLagVarianceFactor(), 0.0d);
+
+        // Check time lag variance threshold configured value
+        assertEquals(60.0, pressureSettings.getUploadTimeLagVarianceFactor(), 0.0d);
+
+        // Check minimum consecutive failures limit configured value
+        assertEquals(121, pressureSettings.getMinConsecutiveFailuresLimit());
+    }
+
+    public void testUpdateAfterGetDefaultSettings() {
+        RemoteStorePressureSettings pressureSettings = new RemoteStorePressureSettings(
+            clusterService,
+            Settings.EMPTY,
+            mock(RemoteStorePressureService.class)
+        );
+
+        Settings newSettings = Settings.builder()
+            .put(RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), true)
+            .put(RemoteStorePressureSettings.BYTES_LAG_VARIANCE_FACTOR.getKey(), 50.0)
+            .put(RemoteStorePressureSettings.UPLOAD_TIME_LAG_VARIANCE_FACTOR.getKey(), 60.0)
+            .put(RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT.getKey(), 121)
+            .build();
+        clusterService.getClusterSettings().applySettings(newSettings);
+
+        // Check updated remote refresh segment pressure enabled is false
+        assertTrue(pressureSettings.isRemoteRefreshSegmentPressureEnabled());
+
+        // Check bytes lag variance threshold updated
+        assertEquals(50.0, pressureSettings.getBytesLagVarianceFactor(), 0.0d);
+
+        // Check time lag variance threshold updated
+        assertEquals(60.0, pressureSettings.getUploadTimeLagVarianceFactor(), 0.0d);
+
+        // Check minimum consecutive failures limit updated
+        assertEquals(121, pressureSettings.getMinConsecutiveFailuresLimit());
+    }
+
+    public void testUpdateAfterGetConfiguredSettings() {
+        Settings settings = Settings.builder()
+            .put(RemoteStorePressureSettings.REMOTE_REFRESH_SEGMENT_PRESSURE_ENABLED.getKey(), true)
+            .put(RemoteStorePressureSettings.BYTES_LAG_VARIANCE_FACTOR.getKey(), 50.0)
+            .put(RemoteStorePressureSettings.UPLOAD_TIME_LAG_VARIANCE_FACTOR.getKey(), 60.0)
+            .put(RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT.getKey(), 121)
+            .build();
+        RemoteStorePressureSettings pressureSettings = new RemoteStorePressureSettings(
+            clusterService,
+            settings,
+            mock(RemoteStorePressureService.class)
+        );
+
+        Settings newSettings = Settings.builder()
+            .put(RemoteStorePressureSettings.BYTES_LAG_VARIANCE_FACTOR.getKey(), 40.0)
+            .put(RemoteStorePressureSettings.UPLOAD_TIME_LAG_VARIANCE_FACTOR.getKey(), 50.0)
+            .put(RemoteStorePressureSettings.MIN_CONSECUTIVE_FAILURES_LIMIT.getKey(), 111)
+            .build();
+
+        clusterService.getClusterSettings().applySettings(newSettings);
+
+        // Check updated remote refresh segment pressure enabled is true
+        assertTrue(pressureSettings.isRemoteRefreshSegmentPressureEnabled());
+
+        // Check bytes lag variance threshold updated
+        assertEquals(40.0, pressureSettings.getBytesLagVarianceFactor(), 0.0d);
+
+        // Check time lag variance threshold updated
+        assertEquals(50.0, pressureSettings.getUploadTimeLagVarianceFactor(), 0.0d);
+
+        // Check minimum consecutive failures limit updated
+        assertEquals(111, pressureSettings.getMinConsecutiveFailuresLimit());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactoryTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactoryTests.java
new file mode 100644
index 0000000000000..c300f316ac633
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStoreStatsTrackerFactoryTests.java
@@ -0,0 +1,119 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import static org.opensearch.index.remote.RemoteStoreTestsHelper.createIndexShard;
+
+public class RemoteStoreStatsTrackerFactoryTests extends OpenSearchTestCase {
+    private ThreadPool threadPool;
+    private ClusterService clusterService;
+    private Settings settings;
+    private ShardId shardId;
+    private IndexShard indexShard;
+    private RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        shardId = new ShardId("index", "uuid", 0);
+        indexShard = createIndexShard(shardId, true);
+        threadPool = new TestThreadPool(getTestName());
+        settings = Settings.builder()
+            .put(
+                RemoteStoreStatsTrackerFactory.MOVING_AVERAGE_WINDOW_SIZE.getKey(),
+                RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE
+            )
+            .build();
+        clusterService = new ClusterService(settings, new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), threadPool);
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, settings);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        threadPool.shutdownNow();
+    }
+
+    public void testAfterIndexShardCreatedForRemoteBackedIndex() {
+        remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+        assertNotNull(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId()));
+    }
+
+    public void testAfterIndexShardCreatedForNonRemoteBackedIndex() {
+        indexShard = createIndexShard(shardId, false);
+        remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+        assertNull(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId()));
+    }
+
+    public void testAfterIndexShardClosed() {
+        remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+        assertNotNull(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId));
+        remoteStoreStatsTrackerFactory.afterIndexShardClosed(shardId, indexShard, indexShard.indexSettings().getSettings());
+        assertNull(remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(shardId));
+    }
+
+    public void testGetConfiguredSettings() {
+        assertEquals(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+    }
+
+    public void testInvalidMovingAverageWindowSize() {
+        Settings settings = Settings.builder()
+            .put(
+                RemoteStoreStatsTrackerFactory.MOVING_AVERAGE_WINDOW_SIZE.getKey(),
+                RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE - 1
+            )
+            .build();
+        assertThrows(
+            "Failed to parse value",
+            IllegalArgumentException.class,
+            () -> new RemoteStoreStatsTrackerFactory(
+                new ClusterService(settings, new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), threadPool),
+                settings
+            )
+        );
+    }
+
+    public void testUpdateAfterGetConfiguredSettings() {
+        assertEquals(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+
+        Settings newSettings = Settings.builder().put(RemoteStoreStatsTrackerFactory.MOVING_AVERAGE_WINDOW_SIZE.getKey(), 102).build();
+
+        clusterService.getClusterSettings().applySettings(newSettings);
+
+        // Check moving average window size updated
+        assertEquals(102, remoteStoreStatsTrackerFactory.getMovingAverageWindowSize());
+    }
+
+    public void testGetDefaultSettings() {
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(
+            new ClusterService(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), threadPool),
+            Settings.EMPTY
+        );
+        // Check moving average window size updated
+        assertEquals(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE,
+            remoteStoreStatsTrackerFactory.getMovingAverageWindowSize()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStoreTestsHelper.java b/server/src/test/java/org/opensearch/index/remote/RemoteStoreTestsHelper.java
new file mode 100644
index 0000000000000..e072d3037caad
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStoreTestsHelper.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.IndexSettingsModule;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Helper functions for Remote Store tests
+ */
+public class RemoteStoreTestsHelper {
+    static IndexShard createIndexShard(ShardId shardId, boolean remoteStoreEnabled) {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, String.valueOf(remoteStoreEnabled))
+            .build();
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test_index", settings);
+        Store store = mock(Store.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.indexSettings()).thenReturn(indexSettings);
+        when(indexShard.shardId()).thenReturn(shardId);
+        when(indexShard.store()).thenReturn(store);
+        return indexShard;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java
new file mode 100644
index 0000000000000..181c846d394a0
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.support.PlainBlobMetadata;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.translog.transfer.TranslogTransferMetadata;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.remote.RemoteStoreUtils.verifyNoMultipleWriters;
+import static org.opensearch.index.store.RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX;
+import static org.opensearch.index.store.RemoteSegmentStoreDirectory.MetadataFilenameUtils.SEPARATOR;
+import static org.opensearch.index.translog.transfer.TranslogTransferMetadata.METADATA_SEPARATOR;
+
+public class RemoteStoreUtilsTests extends OpenSearchTestCase {
+
+    private final String metadataFilename = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        23,
+        34,
+        1,
+        1,
+        "node-1"
+    );
+
+    private final String metadataFilenameDup = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        23,
+        34,
+        2,
+        1,
+        "node-2"
+    );
+    private final String metadataFilename2 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        13,
+        34,
+        1,
+        1,
+        "node-1"
+    );
+
+    private final String oldMetadataFilename = getOldSegmentMetadataFilename(12, 23, 34, 1, 1);
+
+    /*
+    Gives segment metadata filename for <2.11 version
+     */
+    public static String getOldSegmentMetadataFilename(
+        long primaryTerm,
+        long generation,
+        long translogGeneration,
+        long uploadCounter,
+        int metadataVersion
+    ) {
+        return String.join(
+            SEPARATOR,
+            METADATA_PREFIX,
+            RemoteStoreUtils.invertLong(primaryTerm),
+            RemoteStoreUtils.invertLong(generation),
+            RemoteStoreUtils.invertLong(translogGeneration),
+            RemoteStoreUtils.invertLong(uploadCounter),
+            RemoteStoreUtils.invertLong(System.currentTimeMillis()),
+            String.valueOf(metadataVersion)
+        );
+    }
+
+    public static String getOldTranslogMetadataFilename(long primaryTerm, long generation, int metadataVersion) {
+        return String.join(
+            METADATA_SEPARATOR,
+            METADATA_PREFIX,
+            RemoteStoreUtils.invertLong(primaryTerm),
+            RemoteStoreUtils.invertLong(generation),
+            RemoteStoreUtils.invertLong(System.currentTimeMillis()),
+            String.valueOf(metadataVersion)
+        );
+    }
+
+    public void testInvertToStrInvalid() {
+        assertThrows(IllegalArgumentException.class, () -> RemoteStoreUtils.invertLong(-1));
+    }
+
+    public void testInvertToStrValid() {
+        assertEquals("9223372036854774573", RemoteStoreUtils.invertLong(1234));
+        assertEquals("0000000000000001234", RemoteStoreUtils.invertLong(9223372036854774573L));
+    }
+
+    public void testInvertToLongInvalid() {
+        assertThrows(IllegalArgumentException.class, () -> RemoteStoreUtils.invertLong("-5"));
+    }
+
+    public void testInvertToLongValid() {
+        assertEquals(1234, RemoteStoreUtils.invertLong("9223372036854774573"));
+        assertEquals(9223372036854774573L, RemoteStoreUtils.invertLong("0000000000000001234"));
+    }
+
+    public void testinvert() {
+        assertEquals(0, RemoteStoreUtils.invertLong(RemoteStoreUtils.invertLong(0)));
+        assertEquals(Long.MAX_VALUE, RemoteStoreUtils.invertLong(RemoteStoreUtils.invertLong(Long.MAX_VALUE)));
+        for (int i = 0; i < 10; i++) {
+            long num = randomLongBetween(1, Long.MAX_VALUE);
+            assertEquals(num, RemoteStoreUtils.invertLong(RemoteStoreUtils.invertLong(num)));
+        }
+    }
+
+    public void testGetSegmentNameForCfeFile() {
+        assertEquals("_foo", RemoteStoreUtils.getSegmentName("_foo.cfe"));
+    }
+
+    public void testGetSegmentNameForDvmFile() {
+        assertEquals("_bar", RemoteStoreUtils.getSegmentName("_bar_1_Lucene90_0.dvm"));
+    }
+
+    public void testGetSegmentNameWeirdSegmentNameOnlyUnderscore() {
+        // Validate behaviour when segment name contains delimiters only
+        assertEquals("_", RemoteStoreUtils.getSegmentName("_.dvm"));
+    }
+
+    public void testGetSegmentNameUnderscoreDelimiterOverrides() {
+        // Validate behaviour when segment name contains delimiters only
+        assertEquals("_", RemoteStoreUtils.getSegmentName("___.dvm"));
+    }
+
+    public void testGetSegmentNameException() {
+        assertThrows(IllegalArgumentException.class, () -> RemoteStoreUtils.getSegmentName("dvd"));
+    }
+
+    public void testVerifyMultipleWriters_Segment() {
+        List<String> mdFiles = new ArrayList<>();
+        mdFiles.add(metadataFilename);
+        mdFiles.add(metadataFilename2);
+        mdFiles.add(oldMetadataFilename);
+        verifyNoMultipleWriters(mdFiles, RemoteSegmentStoreDirectory.MetadataFilenameUtils::getNodeIdByPrimaryTermAndGen);
+
+        mdFiles.add(metadataFilenameDup);
+        assertThrows(
+            IllegalStateException.class,
+            () -> verifyNoMultipleWriters(mdFiles, RemoteSegmentStoreDirectory.MetadataFilenameUtils::getNodeIdByPrimaryTermAndGen)
+        );
+    }
+
+    public void testVerifyMultipleWriters_Translog() throws InterruptedException {
+        TranslogTransferMetadata tm = new TranslogTransferMetadata(1, 1, 1, 2, "node-1");
+        String mdFilename = tm.getFileName();
+        Thread.sleep(1);
+        TranslogTransferMetadata tm2 = new TranslogTransferMetadata(1, 1, 1, 2, "node-1");
+        String mdFilename2 = tm2.getFileName();
+        List<BlobMetadata> bmList = new LinkedList<>();
+        bmList.add(new PlainBlobMetadata(mdFilename, 1));
+        bmList.add(new PlainBlobMetadata(mdFilename2, 1));
+        bmList.add(new PlainBlobMetadata(getOldTranslogMetadataFilename(1, 1, 1), 1));
+        RemoteStoreUtils.verifyNoMultipleWriters(
+            bmList.stream().map(BlobMetadata::name).collect(Collectors.toList()),
+            TranslogTransferMetadata::getNodeIdByPrimaryTermAndGen
+        );
+
+        bmList = new LinkedList<>();
+        bmList.add(new PlainBlobMetadata(mdFilename, 1));
+        TranslogTransferMetadata tm3 = new TranslogTransferMetadata(1, 1, 1, 2, "node-2");
+        bmList.add(new PlainBlobMetadata(tm3.getFileName(), 1));
+        List<BlobMetadata> finalBmList = bmList;
+        assertThrows(
+            IllegalStateException.class,
+            () -> RemoteStoreUtils.verifyNoMultipleWriters(
+                finalBmList.stream().map(BlobMetadata::name).collect(Collectors.toList()),
+                TranslogTransferMetadata::getNodeIdByPrimaryTermAndGen
+            )
+        );
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteTranslogTransferTrackerTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteTranslogTransferTrackerTests.java
new file mode 100644
index 0000000000000..6b6d388f725f7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteTranslogTransferTrackerTests.java
@@ -0,0 +1,383 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.remote;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+
+public class RemoteTranslogTransferTrackerTests extends OpenSearchTestCase {
+    private ShardId shardId;
+    private RemoteTranslogTransferTracker tracker;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        shardId = new ShardId("index", "uuid", 0);
+    }
+
+    @Before
+    public void initTracker() {
+        tracker = new RemoteTranslogTransferTracker(shardId, RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE);
+    }
+
+    public void testGetShardId() {
+        assertEquals(shardId, tracker.getShardId());
+    }
+
+    public void testAddUploadsStarted() {
+        populateUploadsStarted();
+    }
+
+    public void testAddUploadsFailed() {
+        populateUploadsStarted();
+        assertEquals(0L, tracker.getTotalUploadsFailed());
+        tracker.incrementTotalUploadsFailed();
+        assertEquals(1L, tracker.getTotalUploadsFailed());
+        tracker.incrementTotalUploadsFailed();
+        assertEquals(2L, tracker.getTotalUploadsFailed());
+    }
+
+    public void testInvalidAddUploadsFailed() {
+        populateUploadsStarted();
+        for (int i = 0; i < tracker.getTotalUploadsStarted(); i++) {
+            tracker.incrementTotalUploadsSucceeded();
+        }
+
+        AssertionError error = assertThrows(AssertionError.class, () -> tracker.incrementTotalUploadsFailed());
+        assertTrue(error.getMessage().contains("Sum of failure count ("));
+    }
+
+    public void testAddUploadsSucceeded() {
+        populateUploadsStarted();
+        assertEquals(0L, tracker.getTotalUploadsSucceeded());
+        tracker.incrementTotalUploadsSucceeded();
+        assertEquals(1L, tracker.getTotalUploadsSucceeded());
+        tracker.incrementTotalUploadsSucceeded();
+        assertEquals(2L, tracker.getTotalUploadsSucceeded());
+    }
+
+    public void testInvalidAddUploadsSucceeded() {
+        populateUploadsStarted();
+        for (int i = 0; i < tracker.getTotalUploadsStarted(); i++) {
+            tracker.incrementTotalUploadsFailed();
+        }
+
+        AssertionError error = assertThrows(AssertionError.class, () -> tracker.incrementTotalUploadsSucceeded());
+        assertTrue(error.getMessage().contains("Sum of failure count ("));
+    }
+
+    public void testAddUploadBytesStarted() {
+        populateUploadBytesStarted();
+    }
+
+    public void testAddUploadBytesFailed() {
+        populateUploadBytesStarted();
+        assertEquals(0L, tracker.getUploadBytesFailed());
+        long count1 = randomIntBetween(1, (int) tracker.getUploadBytesStarted() / 4);
+        tracker.addUploadBytesFailed(count1);
+        assertEquals(count1, tracker.getUploadBytesFailed());
+        long count2 = randomIntBetween(1, (int) tracker.getUploadBytesStarted() / 4);
+        tracker.addUploadBytesFailed(count2);
+        assertEquals(count1 + count2, tracker.getUploadBytesFailed());
+    }
+
+    public void testInvalidAddUploadBytesFailed() {
+        populateUploadBytesStarted();
+        tracker.addUploadBytesSucceeded(tracker.getUploadBytesStarted());
+        AssertionError error = assertThrows(AssertionError.class, () -> tracker.addUploadBytesFailed(1L));
+        assertTrue(error.getMessage().contains("Sum of failure count ("));
+    }
+
+    public void testAddUploadBytesSucceeded() {
+        populateUploadBytesStarted();
+        assertEquals(0L, tracker.getUploadBytesSucceeded());
+        long count1 = randomIntBetween(1, (int) tracker.getUploadBytesStarted() / 4);
+        tracker.addUploadBytesSucceeded(count1);
+        assertEquals(count1, tracker.getUploadBytesSucceeded());
+        long count2 = randomIntBetween(1, (int) tracker.getUploadBytesStarted() / 4);
+        tracker.addUploadBytesSucceeded(count2);
+        assertEquals(count1 + count2, tracker.getUploadBytesSucceeded());
+    }
+
+    public void testInvalidAddUploadBytesSucceeded() {
+        populateUploadBytesStarted();
+        tracker.addUploadBytesFailed(tracker.getUploadBytesStarted());
+        AssertionError error = assertThrows(AssertionError.class, () -> tracker.addUploadBytesSucceeded(1L));
+        assertTrue(error.getMessage().contains("Sum of failure count ("));
+    }
+
+    public void testAddUploadTimeInMillis() {
+        assertEquals(0L, tracker.getTotalUploadTimeInMillis());
+        int duration1 = randomIntBetween(10, 50);
+        tracker.addUploadTimeInMillis(duration1);
+        assertEquals(duration1, tracker.getTotalUploadTimeInMillis());
+        int duration2 = randomIntBetween(10, 50);
+        tracker.addUploadTimeInMillis(duration2);
+        assertEquals(duration1 + duration2, tracker.getTotalUploadTimeInMillis());
+    }
+
+    public void testSetLastSuccessfulUploadTimestamp() {
+        assertEquals(0, tracker.getLastSuccessfulUploadTimestamp());
+        long lastUploadTimestamp = System.currentTimeMillis() + randomIntBetween(10, 100);
+        tracker.setLastSuccessfulUploadTimestamp(lastUploadTimestamp);
+        assertEquals(lastUploadTimestamp, tracker.getLastSuccessfulUploadTimestamp());
+    }
+
+    public void testUpdateUploadBytesMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isUploadBytesMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateUploadBytesMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isUploadBytesMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getUploadBytesMovingAverage(), 0.0d);
+        }
+
+        tracker.updateUploadBytesMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isUploadBytesMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadBytesMovingAverage(), 0.0d);
+
+        tracker.updateUploadBytesMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadBytesMovingAverage(), 0.0d);
+    }
+
+    public void testUpdateUploadBytesPerSecMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isUploadBytesPerSecMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateUploadBytesPerSecMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isUploadBytesPerSecMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+        }
+
+        tracker.updateUploadBytesPerSecMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isUploadBytesPerSecMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+
+        tracker.updateUploadBytesPerSecMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadBytesPerSecMovingAverage(), 0.0d);
+    }
+
+    public void testUpdateUploadTimeMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isUploadTimeMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateUploadTimeMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isUploadTimeMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getUploadTimeMovingAverage(), 0.0d);
+        }
+
+        tracker.updateUploadTimeMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isUploadTimeMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadTimeMovingAverage(), 0.0d);
+
+        tracker.updateUploadTimeMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getUploadTimeMovingAverage(), 0.0d);
+    }
+
+    public void testAddDownloadsSucceeded() {
+        assertEquals(0L, tracker.getTotalDownloadsSucceeded());
+        tracker.incrementDownloadsSucceeded();
+        assertEquals(1L, tracker.getTotalDownloadsSucceeded());
+        tracker.incrementDownloadsSucceeded();
+        assertEquals(2L, tracker.getTotalDownloadsSucceeded());
+    }
+
+    public void testAddDownloadBytesSucceeded() {
+        assertEquals(0L, tracker.getDownloadBytesSucceeded());
+        long count1 = randomIntBetween(1, 500);
+        tracker.addDownloadBytesSucceeded(count1);
+        assertEquals(count1, tracker.getDownloadBytesSucceeded());
+        long count2 = randomIntBetween(1, 500);
+        tracker.addDownloadBytesSucceeded(count2);
+        assertEquals(count1 + count2, tracker.getDownloadBytesSucceeded());
+    }
+
+    public void testAddDownloadTimeInMillis() {
+        assertEquals(0L, tracker.getTotalDownloadTimeInMillis());
+        int duration1 = randomIntBetween(10, 50);
+        tracker.addDownloadTimeInMillis(duration1);
+        assertEquals(duration1, tracker.getTotalDownloadTimeInMillis());
+        int duration2 = randomIntBetween(10, 50);
+        tracker.addDownloadTimeInMillis(duration2);
+        assertEquals(duration1 + duration2, tracker.getTotalDownloadTimeInMillis());
+    }
+
+    public void testSetLastSuccessfulDownloadTimestamp() {
+        assertEquals(0, tracker.getLastSuccessfulDownloadTimestamp());
+        long lastSuccessfulDownloadTimestamp = System.currentTimeMillis() + randomIntBetween(10, 100);
+        tracker.setLastSuccessfulDownloadTimestamp(lastSuccessfulDownloadTimestamp);
+        assertEquals(lastSuccessfulDownloadTimestamp, tracker.getLastSuccessfulDownloadTimestamp());
+    }
+
+    public void testUpdateDowmloadBytesMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isDownloadBytesMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateDownloadBytesMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isDownloadBytesMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getDownloadBytesMovingAverage(), 0.0d);
+        }
+
+        tracker.updateDownloadBytesMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isDownloadBytesMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadBytesMovingAverage(), 0.0d);
+
+        tracker.updateDownloadBytesMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadBytesMovingAverage(), 0.0d);
+    }
+
+    public void testUpdateDownloadBytesPerSecMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isDownloadBytesPerSecMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateDownloadBytesPerSecMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isDownloadBytesPerSecMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getDownloadBytesPerSecMovingAverage(), 0.0d);
+        }
+
+        tracker.updateDownloadBytesPerSecMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isDownloadBytesPerSecMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadBytesPerSecMovingAverage(), 0.0d);
+
+        tracker.updateDownloadBytesPerSecMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadBytesPerSecMovingAverage(), 0.0d);
+    }
+
+    public void testUpdateDownloadTimeMovingAverage() {
+        int movingAverageWindowSize = randomIntBetween(
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE_MIN_VALUE,
+            RemoteStoreStatsTrackerFactory.Defaults.MOVING_AVERAGE_WINDOW_SIZE + 5
+        );
+        tracker = new RemoteTranslogTransferTracker(shardId, movingAverageWindowSize);
+        assertFalse(tracker.isDownloadTimeMovingAverageReady());
+
+        long sum = 0;
+        for (int i = 1; i < movingAverageWindowSize; i++) {
+            tracker.updateDownloadTimeMovingAverage(i);
+            sum += i;
+            assertFalse(tracker.isDownloadTimeMovingAverageReady());
+            assertEquals((double) sum / i, tracker.getDownloadTimeMovingAverage(), 0.0d);
+        }
+
+        tracker.updateDownloadTimeMovingAverage(movingAverageWindowSize);
+        sum += movingAverageWindowSize;
+        assertTrue(tracker.isDownloadTimeMovingAverageReady());
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadTimeMovingAverage(), 0.0d);
+
+        tracker.updateDownloadTimeMovingAverage(100);
+        sum = sum + 100 - 1;
+        assertEquals((double) sum / movingAverageWindowSize, tracker.getDownloadTimeMovingAverage(), 0.0d);
+    }
+
+    public void testStatsObjectCreation() {
+        populateDummyStats();
+        RemoteTranslogTransferTracker.Stats actualStats = tracker.stats();
+        assertTrue(tracker.hasSameStatsAs(actualStats));
+    }
+
+    public void testStatsObjectCreationViaStream() throws IOException {
+        populateDummyStats();
+        RemoteTranslogTransferTracker.Stats expectedStats = tracker.stats();
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            expectedStats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteTranslogTransferTracker.Stats deserializedStats = new RemoteTranslogTransferTracker.Stats(in);
+                assertTrue(tracker.hasSameStatsAs(deserializedStats));
+            }
+        }
+    }
+
+    private void populateUploadsStarted() {
+        assertEquals(0L, tracker.getTotalUploadsStarted());
+        tracker.incrementTotalUploadsStarted();
+        assertEquals(1L, tracker.getTotalUploadsStarted());
+        tracker.incrementTotalUploadsStarted();
+        assertEquals(2L, tracker.getTotalUploadsStarted());
+    }
+
+    private void populateUploadBytesStarted() {
+        assertEquals(0L, tracker.getUploadBytesStarted());
+        long count1 = randomIntBetween(500, 1000);
+        tracker.addUploadBytesStarted(count1);
+        assertEquals(count1, tracker.getUploadBytesStarted());
+        long count2 = randomIntBetween(500, 1000);
+        tracker.addUploadBytesStarted(count2);
+        assertEquals(count1 + count2, tracker.getUploadBytesStarted());
+    }
+
+    private void populateDummyStats() {
+        int startedBytesUpload = randomIntBetween(10, 100);
+        tracker.addUploadBytesStarted(startedBytesUpload);
+        tracker.addUploadBytesFailed(randomIntBetween(1, startedBytesUpload / 2));
+        tracker.addUploadBytesSucceeded(randomIntBetween(1, startedBytesUpload / 2));
+
+        tracker.addUploadTimeInMillis(randomIntBetween(10, 100));
+        tracker.setLastSuccessfulUploadTimestamp(System.currentTimeMillis() + randomIntBetween(10, 100));
+
+        tracker.incrementTotalUploadsStarted();
+        tracker.incrementTotalUploadsStarted();
+        tracker.incrementTotalUploadsFailed();
+        tracker.incrementTotalUploadsSucceeded();
+
+        tracker.addDownloadBytesSucceeded(randomIntBetween(10, 100));
+        tracker.addDownloadTimeInMillis(randomIntBetween(10, 100));
+        tracker.setLastSuccessfulDownloadTimestamp(System.currentTimeMillis() + randomIntBetween(10, 100));
+        tracker.incrementDownloadsSucceeded();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/replication/IndexLevelReplicationTests.java b/server/src/test/java/org/opensearch/index/replication/IndexLevelReplicationTests.java
index d262b5abec0f3..33e08a482b9c3 100644
--- a/server/src/test/java/org/opensearch/index/replication/IndexLevelReplicationTests.java
+++ b/server/src/test/java/org/opensearch/index/replication/IndexLevelReplicationTests.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.bulk.BulkItemResponse;
 import org.opensearch.action.bulk.BulkShardRequest;
@@ -48,7 +47,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.iterable.Iterables;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineFactory;
@@ -173,7 +173,7 @@ public void cleanFiles(
     public void testRetryAppendOnlyAfterRecovering() throws Exception {
         try (ReplicationGroup shards = createGroup(0)) {
             shards.startAll();
-            final IndexRequest originalRequest = new IndexRequest(index.getName()).source("{}", XContentType.JSON);
+            final IndexRequest originalRequest = new IndexRequest(index.getName()).source("{}", MediaTypeRegistry.JSON);
             originalRequest.process(Version.CURRENT, null, index.getName());
             final IndexRequest retryRequest = copyIndexRequest(originalRequest);
             retryRequest.onRetry();
@@ -214,7 +214,7 @@ public IndexResult index(Index op) throws IOException {
         }) {
             shards.startAll();
             Thread thread = new Thread(() -> {
-                IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", XContentType.JSON);
+                IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", MediaTypeRegistry.JSON);
                 try {
                     shards.index(indexRequest);
                 } catch (Exception e) {
@@ -244,7 +244,7 @@ public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Vo
     public void testInheritMaxValidAutoIDTimestampOnRecovery() throws Exception {
         try (ReplicationGroup shards = createGroup(0)) {
             shards.startAll();
-            final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", XContentType.JSON);
+            final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", MediaTypeRegistry.JSON);
             indexRequest.onRetry(); // force an update of the timestamp
             final BulkItemResponse response = shards.index(indexRequest);
             assertEquals(DocWriteResponse.Result.CREATED, response.getResponse().getResult());
@@ -320,7 +320,7 @@ public void testConflictingOpsOnReplica() throws Exception {
             shards.startAll();
             List<IndexShard> replicas = shards.getReplicas();
             IndexShard replica1 = replicas.get(0);
-            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", XContentType.JSON);
+            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", MediaTypeRegistry.JSON);
             logger.info("--> isolated replica " + replica1.routingEntry());
             BulkShardRequest replicationRequest = indexOnPrimary(indexRequest, shards.getPrimary());
             for (int i = 1; i < replicas.size(); i++) {
@@ -329,7 +329,7 @@ public void testConflictingOpsOnReplica() throws Exception {
 
             logger.info("--> promoting replica to primary " + replica1.routingEntry());
             shards.promoteReplicaToPrimary(replica1).get();
-            indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"2\"}", XContentType.JSON);
+            indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"2\"}", MediaTypeRegistry.JSON);
             shards.index(indexRequest);
             shards.refresh("test");
             for (IndexShard shard : shards) {
@@ -356,7 +356,7 @@ public void testReplicaTermIncrementWithConcurrentPrimaryPromotion() throws Exce
 
             assertEquals(primaryPrimaryTerm, replica2.getPendingPrimaryTerm());
 
-            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", XContentType.JSON);
+            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", MediaTypeRegistry.JSON);
             BulkShardRequest replicationRequest = indexOnPrimary(indexRequest, replica1);
 
             CyclicBarrier barrier = new CyclicBarrier(2);
@@ -396,7 +396,7 @@ public void testReplicaOperationWithConcurrentPrimaryPromotion() throws Exceptio
         try (ReplicationGroup shards = new ReplicationGroup(buildIndexMetadata(1, mappings))) {
             shards.startAll();
             long primaryPrimaryTerm = shards.getPrimary().getPendingPrimaryTerm();
-            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", XContentType.JSON);
+            IndexRequest indexRequest = new IndexRequest(index.getName()).id("1").source("{ \"f\": \"1\"}", MediaTypeRegistry.JSON);
             BulkShardRequest replicationRequest = indexOnPrimary(indexRequest, shards.getPrimary());
 
             List<IndexShard> replicas = shards.getReplicas();
@@ -476,7 +476,7 @@ protected EngineFactory getEngineFactory(ShardRouting routing) {
             shards.startPrimary();
             long primaryTerm = shards.getPrimary().getPendingPrimaryTerm();
             List<Translog.Operation> expectedTranslogOps = new ArrayList<>();
-            BulkItemResponse indexResp = shards.index(new IndexRequest(index.getName()).id("1").source("{}", XContentType.JSON));
+            BulkItemResponse indexResp = shards.index(new IndexRequest(index.getName()).id("1").source("{}", MediaTypeRegistry.JSON));
             assertThat(indexResp.isFailed(), equalTo(true));
             assertThat(indexResp.getFailure().getCause(), equalTo(indexException));
             expectedTranslogOps.add(new Translog.NoOp(0, primaryTerm, indexException.toString()));
@@ -504,7 +504,7 @@ protected EngineFactory getEngineFactory(ShardRouting routing) {
                 }
             }
             // the failure replicated directly from the replication channel.
-            indexResp = shards.index(new IndexRequest(index.getName()).id("any").source("{}", XContentType.JSON));
+            indexResp = shards.index(new IndexRequest(index.getName()).id("any").source("{}", MediaTypeRegistry.JSON));
             assertThat(indexResp.getFailure().getCause(), equalTo(indexException));
             Translog.NoOp noop2 = new Translog.NoOp(1, primaryTerm, indexException.toString());
             expectedTranslogOps.add(noop2);
@@ -531,7 +531,9 @@ protected EngineFactory getEngineFactory(ShardRouting routing) {
     public void testRequestFailureReplication() throws Exception {
         try (ReplicationGroup shards = createGroup(0)) {
             shards.startAll();
-            BulkItemResponse response = shards.index(new IndexRequest(index.getName()).id("1").source("{}", XContentType.JSON).version(2));
+            BulkItemResponse response = shards.index(
+                new IndexRequest(index.getName()).id("1").source("{}", MediaTypeRegistry.JSON).version(2)
+            );
             assertTrue(response.isFailed());
             assertThat(response.getFailure().getCause(), instanceOf(VersionConflictEngineException.class));
             shards.assertAllEqual(0);
@@ -549,7 +551,7 @@ public void testRequestFailureReplication() throws Exception {
                 shards.addReplica();
             }
             shards.startReplicas(nReplica);
-            response = shards.index(new IndexRequest(index.getName()).id("1").source("{}", XContentType.JSON).version(2));
+            response = shards.index(new IndexRequest(index.getName()).id("1").source("{}", MediaTypeRegistry.JSON).version(2));
             assertTrue(response.isFailed());
             assertThat(response.getFailure().getCause(), instanceOf(VersionConflictEngineException.class));
             shards.assertAllEqual(0);
@@ -582,7 +584,7 @@ public void testSeqNoCollision() throws Exception {
             shards.syncGlobalCheckpoint();
 
             logger.info("--> Isolate replica1");
-            IndexRequest indexDoc1 = new IndexRequest(index.getName()).id("d1").source("{}", XContentType.JSON);
+            IndexRequest indexDoc1 = new IndexRequest(index.getName()).id("d1").source("{}", MediaTypeRegistry.JSON);
             BulkShardRequest replicationRequest = indexOnPrimary(indexDoc1, shards.getPrimary());
             indexOnReplica(replicationRequest, shards, replica2);
 
@@ -602,7 +604,7 @@ public void testSeqNoCollision() throws Exception {
             }
             logger.info("--> Promote replica1 as the primary");
             shards.promoteReplicaToPrimary(replica1).get(); // wait until resync completed.
-            shards.index(new IndexRequest(index.getName()).id("d2").source("{}", XContentType.JSON));
+            shards.index(new IndexRequest(index.getName()).id("d2").source("{}", MediaTypeRegistry.JSON));
             final Translog.Operation op2;
             try (Translog.Snapshot snapshot = getTranslog(replica2).newSnapshot()) {
                 assertThat(snapshot.totalOperations(), equalTo(1));
@@ -652,7 +654,7 @@ public void testLateDeliveryAfterGCTriggeredOnReplica() throws Exception {
 
             updateGCDeleteCycle(replica, gcInterval);
             final BulkShardRequest indexRequest = indexOnPrimary(
-                new IndexRequest(index.getName()).id("d1").source("{}", XContentType.JSON),
+                new IndexRequest(index.getName()).id("d1").source("{}", MediaTypeRegistry.JSON),
                 primary
             );
             final BulkShardRequest deleteRequest = deleteOnPrimary(new DeleteRequest(index.getName()).id("d1"), primary);
@@ -689,7 +691,7 @@ public void testOutOfOrderDeliveryForAppendOnlyOperations() throws Exception {
             final IndexShard replica = shards.getReplicas().get(0);
             // Append-only request - without id
             final BulkShardRequest indexRequest = indexOnPrimary(
-                new IndexRequest(index.getName()).id(null).source("{}", XContentType.JSON),
+                new IndexRequest(index.getName()).id(null).source("{}", MediaTypeRegistry.JSON),
                 primary
             );
             final String docId = Iterables.get(getShardDocUIDs(primary), 0);
@@ -709,7 +711,7 @@ public void testIndexingOptimizationUsingSequenceNumbers() throws Exception {
             for (int i = 0; i < numDocs; i++) {
                 String id = Integer.toString(randomIntBetween(1, 100));
                 if (randomBoolean()) {
-                    group.index(new IndexRequest(index.getName()).id(id).source("{}", XContentType.JSON));
+                    group.index(new IndexRequest(index.getName()).id(id).source("{}", MediaTypeRegistry.JSON));
                     if (liveDocs.add(id) == false) {
                         versionLookups++;
                     }
diff --git a/server/src/test/java/org/opensearch/index/replication/RecoveryDuringReplicationTests.java b/server/src/test/java/org/opensearch/index/replication/RecoveryDuringReplicationTests.java
index add2ecd34e3af..17b5440ab5424 100644
--- a/server/src/test/java/org/opensearch/index/replication/RecoveryDuringReplicationTests.java
+++ b/server/src/test/java/org/opensearch/index/replication/RecoveryDuringReplicationTests.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequest;
 import org.opensearch.action.bulk.BulkShardRequest;
@@ -46,11 +45,12 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.ShardRouting;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.DocIdSeqNoAndSource;
@@ -69,9 +69,9 @@
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.common.ReplicationListener;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -141,7 +141,7 @@ public void testRecoveryToReplicaThatReceivedExtraDocument() throws Exception {
             shards.startAll();
             final int docs = randomIntBetween(0, 16);
             for (int i = 0; i < docs; i++) {
-                shards.index(new IndexRequest("index").id(Integer.toString(i)).source("{}", XContentType.JSON));
+                shards.index(new IndexRequest("index").id(Integer.toString(i)).source("{}", MediaTypeRegistry.JSON));
             }
 
             shards.flush();
@@ -152,18 +152,19 @@ public void testRecoveryToReplicaThatReceivedExtraDocument() throws Exception {
             final IndexShard remainingReplica = shards.getReplicas().get(1);
             // slip the extra document into the replica
             remainingReplica.applyIndexOperationOnReplica(
+                "id",
                 remainingReplica.getLocalCheckpoint() + 1,
                 remainingReplica.getOperationPrimaryTerm(),
                 1,
                 randomNonNegativeLong(),
                 false,
-                new SourceToParse("index", "replica", new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse("index", "replica", new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             shards.promoteReplicaToPrimary(promotedReplica).get();
-            oldPrimary.close("demoted", randomBoolean());
+            oldPrimary.close("demoted", randomBoolean(), false);
             oldPrimary.store().close();
             shards.removeReplica(remainingReplica);
-            remainingReplica.close("disconnected", false);
+            remainingReplica.close("disconnected", false, false);
             remainingReplica.store().close();
             // randomly introduce a conflicting document
             final boolean extra = randomBoolean();
@@ -171,7 +172,7 @@ public void testRecoveryToReplicaThatReceivedExtraDocument() throws Exception {
                 promotedReplica.applyIndexOperationOnPrimary(
                     Versions.MATCH_ANY,
                     VersionType.INTERNAL,
-                    new SourceToParse("index", "primary", new BytesArray("{}"), XContentType.JSON),
+                    new SourceToParse("index", "primary", new BytesArray("{}"), MediaTypeRegistry.JSON),
                     SequenceNumbers.UNASSIGNED_SEQ_NO,
                     0,
                     IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -208,7 +209,8 @@ public void testRecoveryAfterPrimaryPromotion() throws Exception {
                 final int rollbackDocs = randomIntBetween(1, 5);
                 logger.info("--> indexing {} rollback docs", rollbackDocs);
                 for (int i = 0; i < rollbackDocs; i++) {
-                    final IndexRequest indexRequest = new IndexRequest(index.getName()).id("rollback_" + i).source("{}", XContentType.JSON);
+                    final IndexRequest indexRequest = new IndexRequest(index.getName()).id("rollback_" + i)
+                        .source("{}", MediaTypeRegistry.JSON);
                     final BulkShardRequest bulkShardRequest = indexOnPrimary(indexRequest, oldPrimary);
                     indexOnReplica(bulkShardRequest, shards, replica);
                 }
@@ -288,7 +290,7 @@ public void testRecoveryAfterPrimaryPromotion() throws Exception {
                 newPrimary.flush(new FlushRequest());
             }
 
-            oldPrimary.close("demoted", false);
+            oldPrimary.close("demoted", false, false);
             oldPrimary.store().close();
 
             IndexShard newReplica = shards.addReplicaWithExistingPath(oldPrimary.shardPath(), oldPrimary.routingEntry().currentNodeId());
@@ -326,7 +328,7 @@ public void testReplicaRollbackStaleDocumentsInPeerRecovery() throws Exception {
             int staleDocs = scaledRandomIntBetween(1, 10);
             logger.info("--> indexing {} stale docs", staleDocs);
             for (int i = 0; i < staleDocs; i++) {
-                final IndexRequest indexRequest = new IndexRequest(index.getName()).id("stale_" + i).source("{}", XContentType.JSON);
+                final IndexRequest indexRequest = new IndexRequest(index.getName()).id("stale_" + i).source("{}", MediaTypeRegistry.JSON);
                 final BulkShardRequest bulkShardRequest = indexOnPrimary(indexRequest, oldPrimary);
                 indexOnReplica(bulkShardRequest, shards, replica);
             }
@@ -334,7 +336,7 @@ public void testReplicaRollbackStaleDocumentsInPeerRecovery() throws Exception {
             shards.promoteReplicaToPrimary(newPrimary).get();
             // Recover a replica should rollback the stale documents
             shards.removeReplica(replica);
-            replica.close("recover replica - first time", false);
+            replica.close("recover replica - first time", false, false);
             replica.store().close();
             replica = shards.addReplicaWithExistingPath(replica.shardPath(), replica.routingEntry().currentNodeId());
             shards.recoverReplica(replica);
@@ -345,7 +347,7 @@ public void testReplicaRollbackStaleDocumentsInPeerRecovery() throws Exception {
             assertThat(replica.getLastSyncedGlobalCheckpoint(), equalTo(replica.seqNoStats().getMaxSeqNo()));
             // Recover a replica again should also rollback the stale documents.
             shards.removeReplica(replica);
-            replica.close("recover replica - second time", false);
+            replica.close("recover replica - second time", false, false);
             replica.store().close();
             IndexShard anotherReplica = shards.addReplicaWithExistingPath(replica.shardPath(), replica.routingEntry().currentNodeId());
             shards.recoverReplica(anotherReplica);
@@ -363,7 +365,7 @@ public void testResyncAfterPrimaryPromotion() throws Exception {
 
             for (int i = 0; i < initialDocs; i++) {
                 final IndexRequest indexRequest = new IndexRequest(index.getName()).id("initial_doc_" + i)
-                    .source("{ \"f\": \"normal\"}", XContentType.JSON);
+                    .source("{ \"f\": \"normal\"}", MediaTypeRegistry.JSON);
                 shards.index(indexRequest);
             }
 
@@ -381,7 +383,7 @@ public void testResyncAfterPrimaryPromotion() throws Exception {
             logger.info("--> indexing {} extra docs", extraDocs);
             for (int i = 0; i < extraDocs; i++) {
                 final IndexRequest indexRequest = new IndexRequest(index.getName()).id("extra_doc_" + i)
-                    .source("{ \"f\": \"normal\"}", XContentType.JSON);
+                    .source("{ \"f\": \"normal\"}", MediaTypeRegistry.JSON);
                 final BulkShardRequest bulkShardRequest = indexOnPrimary(indexRequest, oldPrimary);
                 indexOnReplica(bulkShardRequest, shards, newPrimary);
             }
@@ -390,7 +392,7 @@ public void testResyncAfterPrimaryPromotion() throws Exception {
             logger.info("--> indexing {} extra docs to be trimmed", extraDocsToBeTrimmed);
             for (int i = 0; i < extraDocsToBeTrimmed; i++) {
                 final IndexRequest indexRequest = new IndexRequest(index.getName()).id("extra_trimmed_" + i)
-                    .source("{ \"f\": \"trimmed\"}", XContentType.JSON);
+                    .source("{ \"f\": \"trimmed\"}", MediaTypeRegistry.JSON);
                 final BulkShardRequest bulkShardRequest = indexOnPrimary(indexRequest, oldPrimary);
                 // have to replicate to another replica != newPrimary one - the subject to trim
                 indexOnReplica(bulkShardRequest, shards, justReplica);
@@ -458,7 +460,7 @@ protected EngineFactory getEngineFactory(ShardRouting routing) {
                 final String id = "pending_" + i;
                 threadPool.generic().submit(() -> {
                     try {
-                        shards.index(new IndexRequest(index.getName()).id(id).source("{}", XContentType.JSON));
+                        shards.index(new IndexRequest(index.getName()).id(id).source("{}", MediaTypeRegistry.JSON));
                     } catch (Exception e) {
                         throw new AssertionError(e);
                     } finally {
@@ -549,7 +551,7 @@ public void indexTranslogOperations(
                         replicaEngineFactory.latchIndexers(1);
                         threadPool.generic().submit(() -> {
                             try {
-                                shards.index(new IndexRequest(index.getName()).id("pending").source("{}", XContentType.JSON));
+                                shards.index(new IndexRequest(index.getName()).id("pending").source("{}", MediaTypeRegistry.JSON));
                             } catch (final Exception e) {
                                 throw new RuntimeException(e);
                             } finally {
@@ -561,7 +563,7 @@ public void indexTranslogOperations(
                             replicaEngineFactory.awaitIndexersLatch();
                             // unblock indexing for the next doc
                             replicaEngineFactory.allowIndexing();
-                            shards.index(new IndexRequest(index.getName()).id("completed").source("{}", XContentType.JSON));
+                            shards.index(new IndexRequest(index.getName()).id("completed").source("{}", MediaTypeRegistry.JSON));
                             pendingDocActiveWithExtraDocIndexed.countDown();
                         } catch (final Exception e) {
                             throw new AssertionError(e);
@@ -601,7 +603,7 @@ public void indexTranslogOperations(
             // wait for the translog phase to complete and the recovery to block global checkpoint advancement
             assertBusy(() -> assertTrue(shards.getPrimary().pendingInSync()));
             {
-                shards.index(new IndexRequest(index.getName()).id("last").source("{}", XContentType.JSON));
+                shards.index(new IndexRequest(index.getName()).id("last").source("{}", MediaTypeRegistry.JSON));
                 final long expectedDocs = docs + 3L;
                 assertThat(shards.getPrimary().getLocalCheckpoint(), equalTo(expectedDocs - 1));
                 // recovery is now in the process of being completed, therefore the global checkpoint can not have advanced on the primary
@@ -636,7 +638,7 @@ public void testTransferMaxSeenAutoIdTimestampOnResync() throws Exception {
             long maxTimestampOnReplica2 = -1;
             List<IndexRequest> replicationRequests = new ArrayList<>();
             for (int numDocs = between(1, 10), i = 0; i < numDocs; i++) {
-                final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", XContentType.JSON);
+                final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", MediaTypeRegistry.JSON);
                 indexRequest.process(Version.CURRENT, null, index.getName());
                 final IndexRequest copyRequest;
                 if (randomBoolean()) {
@@ -694,10 +696,10 @@ public void testAddNewReplicas() throws Exception {
                             int nextId = docId.incrementAndGet();
                             if (appendOnly) {
                                 String id = randomBoolean() ? Integer.toString(nextId) : null;
-                                shards.index(new IndexRequest(index.getName()).id(id).source("{}", XContentType.JSON));
+                                shards.index(new IndexRequest(index.getName()).id(id).source("{}", MediaTypeRegistry.JSON));
                             } else if (frequently()) {
                                 String id = Integer.toString(frequently() ? nextId : between(0, nextId));
-                                shards.index(new IndexRequest(index.getName()).id(id).source("{}", XContentType.JSON));
+                                shards.index(new IndexRequest(index.getName()).id(id).source("{}", MediaTypeRegistry.JSON));
                             } else {
                                 String id = Integer.toString(between(0, nextId));
                                 shards.delete(new DeleteRequest(index.getName()).id(id));
@@ -735,7 +737,7 @@ public void testRollbackOnPromotion() throws Exception {
             int inFlightOps = scaledRandomIntBetween(10, 200);
             for (int i = 0; i < inFlightOps; i++) {
                 String id = "extra-" + i;
-                IndexRequest primaryRequest = new IndexRequest(index.getName()).id(id).source("{}", XContentType.JSON);
+                IndexRequest primaryRequest = new IndexRequest(index.getName()).id(id).source("{}", MediaTypeRegistry.JSON);
                 BulkShardRequest replicationRequest = indexOnPrimary(primaryRequest, shards.getPrimary());
                 for (IndexShard replica : shards.getReplicas()) {
                     if (randomBoolean()) {
@@ -809,7 +811,7 @@ public BlockingTarget(
             CountDownLatch releaseRecovery,
             IndexShard shard,
             DiscoveryNode sourceNode,
-            PeerRecoveryTargetService.RecoveryListener listener,
+            ReplicationListener listener,
             Logger logger
         ) {
             super(shard, sourceNode, listener);
diff --git a/server/src/test/java/org/opensearch/index/replication/RetentionLeasesReplicationTests.java b/server/src/test/java/org/opensearch/index/replication/RetentionLeasesReplicationTests.java
index 143d11bbbf13f..8c59e92a3fe8a 100644
--- a/server/src/test/java/org/opensearch/index/replication/RetentionLeasesReplicationTests.java
+++ b/server/src/test/java/org/opensearch/index/replication/RetentionLeasesReplicationTests.java
@@ -32,19 +32,19 @@
 
 package org.opensearch.index.replication;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.seqno.RetentionLease;
 import org.opensearch.index.seqno.RetentionLeaseSyncAction;
 import org.opensearch.index.seqno.RetentionLeaseUtils;
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.VersionUtils;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/index/search/MultiMatchQueryTests.java b/server/src/test/java/org/opensearch/index/search/MultiMatchQueryTests.java
index f0a70b55e0fdd..0f173e1ac171e 100644
--- a/server/src/test/java/org/opensearch/index/search/MultiMatchQueryTests.java
+++ b/server/src/test/java/org/opensearch/index/search/MultiMatchQueryTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.search;
 
-import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.BlendedTermQuery;
 import org.apache.lucene.search.BooleanClause;
@@ -44,8 +43,8 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.SynonymQuery;
 import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.tests.analysis.MockSynonymAnalyzer;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.settings.Settings;
@@ -58,8 +57,8 @@
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.search.MultiMatchQuery.FieldAndBoost;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.MockKeywordPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.junit.Before;
 
 import java.io.IOException;
@@ -111,12 +110,9 @@ public void setup() throws IOException {
     }
 
     public void testCrossFieldMultiMatchQuery() throws IOException {
-        QueryShardContext queryShardContext = indexService.newQueryShardContext(
-            randomInt(20),
-            null,
-            () -> { throw new UnsupportedOperationException(); },
-            null
-        );
+        QueryShardContext queryShardContext = indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null);
         queryShardContext.setAllowUnmappedFields(true);
         for (float tieBreaker : new float[] { 0.0f, 0.5f }) {
             Query parsedQuery = multiMatchQuery("banon").field("name.first", 2)
@@ -141,14 +137,9 @@ public void testBlendTerms() {
         Term[] terms = new Term[] { new Term("foo", "baz"), new Term("bar", "baz") };
         float[] boosts = new float[] { 2, 3 };
         Query expected = BlendedTermQuery.dismaxBlendedQuery(terms, boosts, 1.0f);
-        Query actual = MultiMatchQuery.blendTerm(
-            indexService.newQueryShardContext(randomInt(20), null, () -> { throw new UnsupportedOperationException(); }, null),
-            new BytesRef("baz"),
-            null,
-            1f,
-            false,
-            Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3))
-        );
+        Query actual = MultiMatchQuery.blendTerm(indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null), new BytesRef("baz"), null, 1f, false, Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3)));
         assertEquals(expected, actual);
     }
 
@@ -160,14 +151,9 @@ public void testBlendTermsWithFieldBoosts() {
         Term[] terms = new Term[] { new Term("foo", "baz"), new Term("bar", "baz") };
         float[] boosts = new float[] { 200, 30 };
         Query expected = BlendedTermQuery.dismaxBlendedQuery(terms, boosts, 1.0f);
-        Query actual = MultiMatchQuery.blendTerm(
-            indexService.newQueryShardContext(randomInt(20), null, () -> { throw new UnsupportedOperationException(); }, null),
-            new BytesRef("baz"),
-            null,
-            1f,
-            false,
-            Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3))
-        );
+        Query actual = MultiMatchQuery.blendTerm(indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null), new BytesRef("baz"), null, 1f, false, Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3)));
         assertEquals(expected, actual);
     }
 
@@ -188,14 +174,9 @@ public Query termQuery(Object value, QueryShardContext context) {
             ),
             1f
         );
-        Query actual = MultiMatchQuery.blendTerm(
-            indexService.newQueryShardContext(randomInt(20), null, () -> { throw new UnsupportedOperationException(); }, null),
-            new BytesRef("baz"),
-            null,
-            1f,
-            true,
-            Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3))
-        );
+        Query actual = MultiMatchQuery.blendTerm(indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null), new BytesRef("baz"), null, 1f, true, Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3)));
         assertEquals(expected, actual);
     }
 
@@ -208,14 +189,9 @@ public Query termQuery(Object value, QueryShardContext context) {
         };
         expectThrows(
             IllegalArgumentException.class,
-            () -> MultiMatchQuery.blendTerm(
-                indexService.newQueryShardContext(randomInt(20), null, () -> { throw new UnsupportedOperationException(); }, null),
-                new BytesRef("baz"),
-                null,
-                1f,
-                false,
-                Arrays.asList(new FieldAndBoost(ft, 1))
-            )
+            () -> MultiMatchQuery.blendTerm(indexService.newQueryShardContext(randomInt(20), null, () -> {
+                throw new UnsupportedOperationException();
+            }, null), new BytesRef("baz"), null, 1f, false, Arrays.asList(new FieldAndBoost(ft, 1)))
         );
     }
 
@@ -232,24 +208,16 @@ public Query termQuery(Object value, QueryShardContext context) {
         Query expectedDisjunct1 = BlendedTermQuery.dismaxBlendedQuery(terms, boosts, 1.0f);
         Query expectedDisjunct2 = new BoostQuery(new MatchAllDocsQuery(), 3);
         Query expected = new DisjunctionMaxQuery(Arrays.asList(expectedDisjunct2, expectedDisjunct1), 1.0f);
-        Query actual = MultiMatchQuery.blendTerm(
-            indexService.newQueryShardContext(randomInt(20), null, () -> { throw new UnsupportedOperationException(); }, null),
-            new BytesRef("baz"),
-            null,
-            1f,
-            false,
-            Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3))
-        );
+        Query actual = MultiMatchQuery.blendTerm(indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null), new BytesRef("baz"), null, 1f, false, Arrays.asList(new FieldAndBoost(ft1, 2), new FieldAndBoost(ft2, 3)));
         assertEquals(expected, actual);
     }
 
     public void testMultiMatchCrossFieldsWithSynonyms() throws IOException {
-        QueryShardContext queryShardContext = indexService.newQueryShardContext(
-            randomInt(20),
-            null,
-            () -> { throw new UnsupportedOperationException(); },
-            null
-        );
+        QueryShardContext queryShardContext = indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null);
 
         MultiMatchQuery parser = new MultiMatchQuery(queryShardContext);
         parser.setAnalyzer(new MockSynonymAnalyzer());
@@ -279,12 +247,9 @@ public void testMultiMatchCrossFieldsWithSynonyms() throws IOException {
     }
 
     public void testMultiMatchCrossFieldsWithSynonymsPhrase() throws IOException {
-        QueryShardContext queryShardContext = indexService.newQueryShardContext(
-            randomInt(20),
-            null,
-            () -> { throw new UnsupportedOperationException(); },
-            null
-        );
+        QueryShardContext queryShardContext = indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null);
         MultiMatchQuery parser = new MultiMatchQuery(queryShardContext);
         parser.setAnalyzer(new MockSynonymAnalyzer());
         Map<String, Float> fieldNames = new HashMap<>();
@@ -319,38 +284,34 @@ public void testKeywordSplitQueriesOnWhitespace() throws IOException {
                 .build()
         );
         MapperService mapperService = indexService.mapperService();
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("field")
-                .field("type", "keyword")
-                .endObject()
-                .startObject("field_normalizer")
-                .field("type", "keyword")
-                .field("normalizer", "my_lowercase")
-                .endObject()
-                .startObject("field_split")
-                .field("type", "keyword")
-                .field("split_queries_on_whitespace", true)
-                .endObject()
-                .startObject("field_split_normalizer")
-                .field("type", "keyword")
-                .field("normalizer", "my_lowercase")
-                .field("split_queries_on_whitespace", true)
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "keyword")
+            .endObject()
+            .startObject("field_normalizer")
+            .field("type", "keyword")
+            .field("normalizer", "my_lowercase")
+            .endObject()
+            .startObject("field_split")
+            .field("type", "keyword")
+            .field("split_queries_on_whitespace", true)
+            .endObject()
+            .startObject("field_split_normalizer")
+            .field("type", "keyword")
+            .field("normalizer", "my_lowercase")
+            .field("split_queries_on_whitespace", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         mapperService.merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
-        QueryShardContext queryShardContext = indexService.newQueryShardContext(
-            randomInt(20),
-            null,
-            () -> { throw new UnsupportedOperationException(); },
-            null
-        );
+        QueryShardContext queryShardContext = indexService.newQueryShardContext(randomInt(20), null, () -> {
+            throw new UnsupportedOperationException();
+        }, null);
         MultiMatchQuery parser = new MultiMatchQuery(queryShardContext);
         Map<String, Float> fieldNames = new HashMap<>();
         fieldNames.put("field", 1.0f);
diff --git a/server/src/test/java/org/opensearch/index/search/NestedHelperTests.java b/server/src/test/java/org/opensearch/index/search/NestedHelperTests.java
index c02df8168afee..7ffcc0fb7437a 100644
--- a/server/src/test/java/org/opensearch/index/search/NestedHelperTests.java
+++ b/server/src/test/java/org/opensearch/index/search/NestedHelperTests.java
@@ -43,10 +43,11 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.join.ScoreMode;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.NestedQueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
@@ -324,7 +325,7 @@ public void testNested() throws IOException {
 
         Query expectedChildQuery = new BooleanQuery.Builder().add(new MatchAllDocsQuery(), Occur.MUST)
             // we automatically add a filter since the inner query might match non-nested docs
-            .add(new TermQuery(new Term("_type", "__nested1")), Occur.FILTER)
+            .add(new TermQuery(new Term(NestedPathFieldMapper.NAME, "nested1")), Occur.FILTER)
             .build();
         assertEquals(expectedChildQuery, query.getChildQuery());
 
@@ -352,7 +353,7 @@ public void testNested() throws IOException {
 
         // we need to add the filter again because of include_in_parent
         expectedChildQuery = new BooleanQuery.Builder().add(new TermQuery(new Term("nested2.foo", "bar")), Occur.MUST)
-            .add(new TermQuery(new Term("_type", "__nested2")), Occur.FILTER)
+            .add(new TermQuery(new Term(NestedPathFieldMapper.NAME, "nested2")), Occur.FILTER)
             .build();
         assertEquals(expectedChildQuery, query.getChildQuery());
 
@@ -367,7 +368,7 @@ public void testNested() throws IOException {
 
         // we need to add the filter again because of include_in_root
         expectedChildQuery = new BooleanQuery.Builder().add(new TermQuery(new Term("nested3.foo", "bar")), Occur.MUST)
-            .add(new TermQuery(new Term("_type", "__nested3")), Occur.FILTER)
+            .add(new TermQuery(new Term(NestedPathFieldMapper.NAME, "nested3")), Occur.FILTER)
             .build();
         assertEquals(expectedChildQuery, query.getChildQuery());
 
diff --git a/server/src/test/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQueryTests.java b/server/src/test/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQueryTests.java
index 39160b1ac49bc..45172c946ab36 100644
--- a/server/src/test/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQueryTests.java
+++ b/server/src/test/java/org/opensearch/index/search/OpenSearchToParentBlockJoinQueryTests.java
@@ -34,6 +34,7 @@
 
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.PhraseQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
@@ -112,7 +113,7 @@ public void testRewrite() throws IOException {
             ScoreMode.Avg,
             "nested"
         );
-        Query rewritten = q.rewrite(new MultiReader());
+        Query rewritten = q.rewrite(new IndexSearcher(new MultiReader()));
         assertEquals(expected, rewritten);
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/search/geo/GeoPointParsingTests.java b/server/src/test/java/org/opensearch/index/search/geo/GeoPointParsingTests.java
index 6b937ad881f00..097a6827a71a1 100644
--- a/server/src/test/java/org/opensearch/index/search/geo/GeoPointParsingTests.java
+++ b/server/src/test/java/org/opensearch/index/search/geo/GeoPointParsingTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.index.search.geo;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.geo.RandomGeoGenerator;
 
@@ -50,6 +50,7 @@
 import static org.hamcrest.Matchers.is;
 
 public class GeoPointParsingTests extends OpenSearchTestCase {
+    private static final String ERR_MSG_INVALID_FIELDS = "field must be either [lon|lat], [type|coordinates], or [geohash]";
     private static final double TOLERANCE = 1E-5;
 
     public void testGeoPointReset() throws IOException {
@@ -142,12 +143,12 @@ public void testInvalidPointEmbeddedObject() throws IOException {
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("field must be either [lat], [lon] or [geohash]"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
         try (XContentParser parser2 = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser2.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(toObject(parser2), randomBoolean()));
-            assertThat(e.getMessage(), is("field must be either [lat], [lon] or [geohash]"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
     }
 
@@ -160,12 +161,12 @@ public void testInvalidPointLatHashMix() throws IOException {
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("field must be either lat/lon or geohash"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
         try (XContentParser parser2 = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser2.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(toObject(parser2), randomBoolean()));
-            assertThat(e.getMessage(), is("field must be either lat/lon or geohash"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
     }
 
@@ -179,12 +180,12 @@ public void testInvalidPointLonHashMix() throws IOException {
             parser.nextToken();
 
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("field must be either lat/lon or geohash"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
         try (XContentParser parser2 = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser2.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(toObject(parser2), randomBoolean()));
-            assertThat(e.getMessage(), is("field must be either lat/lon or geohash"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
     }
 
@@ -197,13 +198,13 @@ public void testInvalidField() throws IOException {
         try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("field must be either [lat], [lon] or [geohash]"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
 
         try (XContentParser parser2 = createParser(JsonXContent.jsonXContent, BytesReference.bytes(content))) {
             parser2.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(toObject(parser2), randomBoolean()));
-            assertThat(e.getMessage(), is("field must be either [lat], [lon] or [geohash]"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/index/search/geo/GeoUtilsTests.java b/server/src/test/java/org/opensearch/index/search/geo/GeoUtilsTests.java
index bb4b057d01414..f29b4a25c29d4 100644
--- a/server/src/test/java/org/opensearch/index/search/geo/GeoUtilsTests.java
+++ b/server/src/test/java/org/opensearch/index/search/geo/GeoUtilsTests.java
@@ -38,16 +38,18 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.GeoUtils;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.test.OpenSearchTestCase;
-import org.locationtech.spatial4j.context.SpatialContext;
-import org.locationtech.spatial4j.distance.DistanceUtils;
+import org.opensearch.test.geo.RandomGeoGenerator;
 
 import java.io.IOException;
 
+import org.locationtech.spatial4j.context.SpatialContext;
+import org.locationtech.spatial4j.distance.DistanceUtils;
+
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.closeTo;
@@ -59,6 +61,7 @@
 import static org.hamcrest.Matchers.not;
 
 public class GeoUtilsTests extends OpenSearchTestCase {
+    private static final String ERR_MSG_INVALID_FIELDS = "field must be either [lon|lat], [type|coordinates], or [geohash]";
     private static final char[] BASE_32 = {
         '0',
         '1',
@@ -601,7 +604,7 @@ public void testParseGeoPointLonWrongType() throws IOException {
         try (XContentParser parser = createParser(json)) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("longitude must be a number"));
+            assertThat(e.getMessage(), is("lon must be a number"));
             assertThat(parser.currentToken(), is(Token.END_OBJECT));
             assertNull(parser.nextToken());
         }
@@ -613,7 +616,7 @@ public void testParseGeoPointLatWrongType() throws IOException {
         try (XContentParser parser = createParser(json)) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("latitude must be a number"));
+            assertThat(e.getMessage(), is("lat must be a number"));
             assertThat(parser.currentToken(), is(Token.END_OBJECT));
             assertNull(parser.nextToken());
         }
@@ -626,7 +629,7 @@ public void testParseGeoPointExtraField() throws IOException {
         try (XContentParser parser = createParser(json)) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), is("field must be either [lat], [lon] or [geohash]"));
+            assertThat(e.getMessage(), is(ERR_MSG_INVALID_FIELDS));
         }
     }
 
@@ -638,7 +641,7 @@ public void testParseGeoPointLonLatGeoHash() throws IOException {
         try (XContentParser parser = createParser(json)) {
             parser.nextToken();
             Exception e = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
-            assertThat(e.getMessage(), containsString("field must be either lat/lon or geohash"));
+            assertThat(e.getMessage(), containsString(ERR_MSG_INVALID_FIELDS));
         }
     }
 
@@ -698,6 +701,70 @@ public void testParseGeoPointInvalidType() throws IOException {
         }
     }
 
+    public void testParserGeoPointGeoJson() throws IOException {
+        GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random());
+        double[] coordinates = { geoPoint.getLon(), geoPoint.getLat() };
+        XContentBuilder json1 = jsonBuilder().startObject().field("type", "Point").array("coordinates", coordinates).endObject();
+        try (XContentParser parser = createParser(json1)) {
+            parser.nextToken();
+            GeoPoint paredPoint = GeoUtils.parseGeoPoint(parser);
+            assertEquals(geoPoint, paredPoint);
+        }
+
+        XContentBuilder json2 = jsonBuilder().startObject().field("type", "PoInT").array("coordinates", coordinates).endObject();
+        try (XContentParser parser = createParser(json2)) {
+            parser.nextToken();
+            GeoPoint paredPoint = GeoUtils.parseGeoPoint(parser);
+            assertEquals(geoPoint, paredPoint);
+        }
+    }
+
+    public void testParserGeoPointGeoJsonMissingField() throws IOException {
+        GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random());
+        double[] coordinates = { geoPoint.getLon(), geoPoint.getLat() };
+        XContentBuilder missingType = jsonBuilder().startObject().array("coordinates", coordinates).endObject();
+        expectParseException(missingType, "field [type] missing");
+
+        XContentBuilder missingCoordinates = jsonBuilder().startObject().field("type", "Point").endObject();
+        expectParseException(missingCoordinates, "field [coordinates] missing");
+    }
+
+    public void testParserGeoPointGeoJsonUnknownField() throws IOException {
+        GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random());
+        double[] coordinates = { geoPoint.getLon(), geoPoint.getLat() };
+        XContentBuilder unknownField = jsonBuilder().startObject()
+            .field("type", "Point")
+            .array("coordinates", coordinates)
+            .field("unknown", "value")
+            .endObject();
+        expectParseException(unknownField, "field must be either [lon|lat], [type|coordinates], or [geohash]");
+    }
+
+    public void testParserGeoPointGeoJsonInvalidValue() throws IOException {
+        GeoPoint geoPoint = RandomGeoGenerator.randomPoint(random());
+        double[] coordinates = { geoPoint.getLon(), geoPoint.getLat() };
+        XContentBuilder invalidGeoJsonType = jsonBuilder().startObject()
+            .field("type", "invalid")
+            .array("coordinates", coordinates)
+            .endObject();
+        expectParseException(invalidGeoJsonType, "type must be Point");
+
+        String[] coordinatesInString = { String.valueOf(geoPoint.getLon()), String.valueOf(geoPoint.getLat()) };
+        XContentBuilder invalideCoordinatesType = jsonBuilder().startObject()
+            .field("type", "Point")
+            .array("coordinates", coordinatesInString)
+            .endObject();
+        expectParseException(invalideCoordinatesType, "numeric value expected");
+    }
+
+    private void expectParseException(XContentBuilder content, String errMsg) throws IOException {
+        try (XContentParser parser = createParser(content)) {
+            parser.nextToken();
+            OpenSearchParseException ex = expectThrows(OpenSearchParseException.class, () -> GeoUtils.parseGeoPoint(parser));
+            assertEquals(errMsg, ex.getMessage());
+        }
+    }
+
     public void testPrefixTreeCellSizes() {
         assertThat(GeoUtils.EARTH_SEMI_MAJOR_AXIS, equalTo(DistanceUtils.EARTH_EQUATORIAL_RADIUS_KM * 1000));
         assertThat(GeoUtils.quadTreeCellWidth(0), lessThanOrEqualTo(GeoUtils.EARTH_EQUATOR));
diff --git a/server/src/test/java/org/opensearch/index/search/nested/AbstractNumberNestedSortingTestCase.java b/server/src/test/java/org/opensearch/index/search/nested/AbstractNumberNestedSortingTestCase.java
index 26fd18c9fb558..525c1303ab46b 100644
--- a/server/src/test/java/org/opensearch/index/search/nested/AbstractNumberNestedSortingTestCase.java
+++ b/server/src/test/java/org/opensearch/index/search/nested/AbstractNumberNestedSortingTestCase.java
@@ -51,11 +51,11 @@
 import org.apache.lucene.search.join.ToParentBlockJoinQuery;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.lucene.search.Queries;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.fielddata.AbstractFieldDataTestCase;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.MultiValueMode;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/search/nested/NestedSortingTests.java b/server/src/test/java/org/opensearch/index/search/nested/NestedSortingTests.java
index a8cd6c5411875..8f1a9afa243a3 100644
--- a/server/src/test/java/org/opensearch/index/search/nested/NestedSortingTests.java
+++ b/server/src/test/java/org/opensearch/index/search/nested/NestedSortingTests.java
@@ -55,26 +55,27 @@
 import org.apache.lucene.search.join.QueryBitSetProducer;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.search.join.ToParentBlockJoinQuery;
-import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.fielddata.AbstractFieldDataTestCase;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.NoOrdinalsStringFieldDataTests;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
 import org.opensearch.index.fielddata.plain.PagedBytesIndexFieldData;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.NestedQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.RangeQueryBuilder;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.MultiValueMode;
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.NestedSortBuilder;
@@ -103,14 +104,14 @@ public void testDuel() throws Exception {
             for (int j = 0; j < numChildren; ++j) {
                 Document doc = new Document();
                 doc.add(new StringField("f", TestUtil.randomSimpleString(random(), 2), Field.Store.NO));
-                doc.add(new StringField("__type", "child", Field.Store.NO));
+                doc.add(new StringField(NestedPathFieldMapper.NAME, "child", Field.Store.NO));
                 docs.add(doc);
             }
             if (randomBoolean()) {
                 docs.add(new Document());
             }
             Document parent = new Document();
-            parent.add(new StringField("__type", "parent", Field.Store.NO));
+            parent.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
             docs.add(parent);
             writer.addDocuments(docs);
             if (rarely()) { // we need to have a bit more segments than what RandomIndexWriter would do by default
@@ -149,8 +150,8 @@ private TopDocs getTopDocs(
         int n,
         boolean reverse
     ) throws IOException {
-        Query parentFilter = new TermQuery(new Term("__type", "parent"));
-        Query childFilter = new TermQuery(new Term("__type", "child"));
+        Query parentFilter = new TermQuery(new Term(NestedPathFieldMapper.NAME, "parent"));
+        Query childFilter = new TermQuery(new Term(NestedPathFieldMapper.NAME, "child"));
         SortField sortField = indexFieldData.sortField(missingValue, sortMode, createNested(searcher, parentFilter, childFilter), reverse);
         Query query = new ConstantScoreQuery(parentFilter);
         Sort sort = new Sort(sortField);
@@ -172,7 +173,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "T", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "a", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -192,7 +193,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "T", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "b", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -211,7 +212,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "T", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "c", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -230,7 +231,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "F", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "d", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -250,7 +251,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "F", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "f", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -269,14 +270,14 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "T", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "g", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
 
         // This doc will not be included, because it doesn't have nested docs
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "h", Field.Store.NO));
         writer.addDocument(document);
 
@@ -294,7 +295,7 @@ public void testNestedSorting() throws Exception {
         document.add(new StringField("filter_1", "F", Field.Store.NO));
         docs.add(document);
         document = new Document();
-        document.add(new StringField("__type", "parent", Field.Store.NO));
+        document.add(new StringField(NestedPathFieldMapper.NAME, "parent", Field.Store.NO));
         document.add(new StringField("field1", "i", Field.Store.NO));
         docs.add(document);
         writer.addDocuments(docs);
@@ -316,7 +317,7 @@ public void testNestedSorting() throws Exception {
         reader = OpenSearchDirectoryReader.wrap(reader, new ShardId(indexService.index(), 0));
         IndexSearcher searcher = new IndexSearcher(reader);
         PagedBytesIndexFieldData indexFieldData = getForField("field2");
-        Query parentFilter = new TermQuery(new Term("__type", "parent"));
+        Query parentFilter = new TermQuery(new Term(NestedPathFieldMapper.NAME, "parent"));
         Query childFilter = Queries.not(parentFilter);
         BytesRefFieldComparatorSource nestedComparatorSource = new BytesRefFieldComparatorSource(
             indexFieldData,
@@ -472,53 +473,52 @@ public void testMultiLevelNestedSorting() throws IOException {
             List<Document> book = new ArrayList<>();
             Document document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "Paragraph 1", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 743));
             document.add(new IntPoint("chapters.paragraphs.word_count", 743));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "chapter 3", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 400));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 400));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "Paragraph 1", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 234));
             document.add(new IntPoint("chapters.paragraphs.word_count", 234));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "chapter 2", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 200));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 200));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "Paragraph 2", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 478));
             document.add(new IntPoint("chapters.paragraphs.word_count", 478));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "Paragraph 1", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 849));
             document.add(new IntPoint("chapters.paragraphs.word_count", 849));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "chapter 1", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 1400));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 1400));
             book.add(document);
             document = new Document();
             document.add(new StringField("genre", "science fiction", Field.Store.NO));
-            document.add(new StringField("_type", "_doc", Field.Store.NO));
             document.add(new StringField("_id", "1", Field.Store.YES));
             document.add(new NumericDocValuesField(PRIMARY_TERM_NAME, 0));
             book.add(document);
@@ -528,20 +528,19 @@ public void testMultiLevelNestedSorting() throws IOException {
             List<Document> book = new ArrayList<>();
             Document document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "Introduction", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 76));
             document.add(new IntPoint("chapters.paragraphs.word_count", 76));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "chapter 1", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 20));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 20));
             book.add(document);
             document = new Document();
             document.add(new StringField("genre", "romance", Field.Store.NO));
-            document.add(new StringField("_type", "_doc", Field.Store.NO));
             document.add(new StringField("_id", "2", Field.Store.YES));
             document.add(new NumericDocValuesField(PRIMARY_TERM_NAME, 0));
             book.add(document);
@@ -551,20 +550,19 @@ public void testMultiLevelNestedSorting() throws IOException {
             List<Document> book = new ArrayList<>();
             Document document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "A bad dream", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 976));
             document.add(new IntPoint("chapters.paragraphs.word_count", 976));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "The beginning of the end", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 1200));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 1200));
             book.add(document);
             document = new Document();
             document.add(new StringField("genre", "horror", Field.Store.NO));
-            document.add(new StringField("_type", "_doc", Field.Store.NO));
             document.add(new StringField("_id", "3", Field.Store.YES));
             document.add(new NumericDocValuesField(PRIMARY_TERM_NAME, 0));
             book.add(document);
@@ -574,47 +572,46 @@ public void testMultiLevelNestedSorting() throws IOException {
             List<Document> book = new ArrayList<>();
             Document document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "macaroni", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 180));
             document.add(new IntPoint("chapters.paragraphs.word_count", 180));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "hamburger", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 150));
             document.add(new IntPoint("chapters.paragraphs.word_count", 150));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "tosti", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 120));
             document.add(new IntPoint("chapters.paragraphs.word_count", 120));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "easy meals", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 800));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 800));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.paragraphs.header", "introduction", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters.paragraphs", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters.paragraphs", Field.Store.NO));
             document.add(new TextField("chapters.paragraphs.text", "some text...", Field.Store.NO));
             document.add(new SortedNumericDocValuesField("chapters.paragraphs.word_count", 87));
             document.add(new IntPoint("chapters.paragraphs.word_count", 87));
             book.add(document);
             document = new Document();
             document.add(new TextField("chapters.title", "introduction", Field.Store.NO));
-            document.add(new StringField("_type", "__chapters", Field.Store.NO));
+            document.add(new StringField(NestedPathFieldMapper.NAME, "chapters", Field.Store.NO));
             document.add(new IntPoint("chapters.read_time_seconds", 10));
             document.add(new NumericDocValuesField("chapters.read_time_seconds", 10));
             book.add(document);
             document = new Document();
             document.add(new StringField("genre", "cooking", Field.Store.NO));
-            document.add(new StringField("_type", "_doc", Field.Store.NO));
             document.add(new StringField("_id", "4", Field.Store.YES));
             document.add(new NumericDocValuesField(PRIMARY_TERM_NAME, 0));
             book.add(document);
@@ -624,7 +621,6 @@ public void testMultiLevelNestedSorting() throws IOException {
             List<Document> book = new ArrayList<>();
             Document document = new Document();
             document.add(new StringField("genre", "unknown", Field.Store.NO));
-            document.add(new StringField("_type", "_doc", Field.Store.NO));
             document.add(new StringField("_id", "5", Field.Store.YES));
             document.add(new NumericDocValuesField(PRIMARY_TERM_NAME, 0));
             book.add(document);
@@ -649,15 +645,15 @@ public void testMultiLevelNestedSorting() throws IOException {
         TopFieldDocs topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
         assertThat(topFields.totalHits.value, equalTo(5L));
         assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("2"));
-        assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76L));
+        assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76));
         assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("4"));
-        assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(87L));
+        assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(87));
         assertThat(searcher.doc(topFields.scoreDocs[2].doc).get("_id"), equalTo("1"));
-        assertThat(((FieldDoc) topFields.scoreDocs[2]).fields[0], equalTo(234L));
+        assertThat(((FieldDoc) topFields.scoreDocs[2]).fields[0], equalTo(234));
         assertThat(searcher.doc(topFields.scoreDocs[3].doc).get("_id"), equalTo("3"));
-        assertThat(((FieldDoc) topFields.scoreDocs[3]).fields[0], equalTo(976L));
+        assertThat(((FieldDoc) topFields.scoreDocs[3]).fields[0], equalTo(976));
         assertThat(searcher.doc(topFields.scoreDocs[4].doc).get("_id"), equalTo("5"));
-        assertThat(((FieldDoc) topFields.scoreDocs[4]).fields[0], equalTo(Long.MAX_VALUE));
+        assertThat(((FieldDoc) topFields.scoreDocs[4]).fields[0], equalTo(Integer.MAX_VALUE));
 
         // Specific genre
         {
@@ -665,25 +661,25 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76));
 
             queryBuilder = new TermQueryBuilder("genre", "science fiction");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("1"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(234L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(234));
 
             queryBuilder = new TermQueryBuilder("genre", "horror");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("3"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976));
 
             queryBuilder = new TermQueryBuilder("genre", "cooking");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87));
         }
 
         // reverse sort order
@@ -693,15 +689,15 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(5L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("3"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976));
             assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("1"));
-            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(849L));
+            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(849));
             assertThat(searcher.doc(topFields.scoreDocs[2].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[2]).fields[0], equalTo(180L));
+            assertThat(((FieldDoc) topFields.scoreDocs[2]).fields[0], equalTo(180));
             assertThat(searcher.doc(topFields.scoreDocs[3].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[3]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[3]).fields[0], equalTo(76));
             assertThat(searcher.doc(topFields.scoreDocs[4].doc).get("_id"), equalTo("5"));
-            assertThat(((FieldDoc) topFields.scoreDocs[4]).fields[0], equalTo(Long.MIN_VALUE));
+            assertThat(((FieldDoc) topFields.scoreDocs[4]).fields[0], equalTo(Integer.MIN_VALUE));
         }
 
         // Specific genre and reverse sort order
@@ -710,25 +706,25 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76));
 
             queryBuilder = new TermQueryBuilder("genre", "science fiction");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("1"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(849L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(849));
 
             queryBuilder = new TermQueryBuilder("genre", "horror");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("3"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(976));
 
             queryBuilder = new TermQueryBuilder("genre", "cooking");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(180L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(180));
         }
 
         // Nested filter + query
@@ -741,17 +737,17 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(new NestedQueryBuilder("chapters", queryBuilder, ScoreMode.None), sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(2L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76));
             assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(87));
 
             sortBuilder.order(SortOrder.DESC);
             topFields = search(new NestedQueryBuilder("chapters", queryBuilder, ScoreMode.None), sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(2L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87));
             assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(76));
         }
 
         // Multiple Nested filters + query
@@ -769,17 +765,17 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(new NestedQueryBuilder("chapters", queryBuilder, ScoreMode.None), sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(2L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87));
             assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(Long.MAX_VALUE));
+            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(Integer.MAX_VALUE));
 
             sortBuilder.order(SortOrder.DESC);
             topFields = search(new NestedQueryBuilder("chapters", queryBuilder, ScoreMode.None), sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(2L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87));
             assertThat(searcher.doc(topFields.scoreDocs[1].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(Long.MIN_VALUE));
+            assertThat(((FieldDoc) topFields.scoreDocs[1]).fields[0], equalTo(Integer.MIN_VALUE));
         }
 
         // Nested filter + Specific genre
@@ -794,25 +790,25 @@ public void testMultiLevelNestedSorting() throws IOException {
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("2"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(76));
 
             queryBuilder = new TermQueryBuilder("genre", "science fiction");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("1"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(Long.MAX_VALUE));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(Integer.MAX_VALUE));
 
             queryBuilder = new TermQueryBuilder("genre", "horror");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("3"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(Long.MAX_VALUE));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(Integer.MAX_VALUE));
 
             queryBuilder = new TermQueryBuilder("genre", "cooking");
             topFields = search(queryBuilder, sortBuilder, queryShardContext, searcher);
             assertThat(topFields.totalHits.value, equalTo(1L));
             assertThat(searcher.doc(topFields.scoreDocs[0].doc).get("_id"), equalTo("4"));
-            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87L));
+            assertThat(((FieldDoc) topFields.scoreDocs[0]).fields[0], equalTo(87));
         }
 
         searcher.getIndexReader().close();
diff --git a/server/src/test/java/org/opensearch/index/search/stats/SearchStatsTests.java b/server/src/test/java/org/opensearch/index/search/stats/SearchStatsTests.java
index 4682d35411b78..c27e4bf27327a 100644
--- a/server/src/test/java/org/opensearch/index/search/stats/SearchStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/search/stats/SearchStatsTests.java
@@ -32,11 +32,20 @@
 
 package org.opensearch.index.search.stats;
 
+import org.opensearch.action.search.SearchPhase;
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchRequestStats;
 import org.opensearch.index.search.stats.SearchStats.Stats;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class SearchStatsTests extends OpenSearchTestCase {
 
@@ -45,9 +54,9 @@ public void testShardLevelSearchGroupStats() throws Exception {
         // let's create two dummy search stats with groups
         Map<String, Stats> groupStats1 = new HashMap<>();
         Map<String, Stats> groupStats2 = new HashMap<>();
-        groupStats2.put("group1", new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1));
-        SearchStats searchStats1 = new SearchStats(new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 0, groupStats1);
-        SearchStats searchStats2 = new SearchStats(new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 0, groupStats2);
+        groupStats2.put("group1", new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1));
+        SearchStats searchStats1 = new SearchStats(new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 0, groupStats1);
+        SearchStats searchStats2 = new SearchStats(new Stats(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 0, groupStats2);
 
         // adding these two search stats and checking group stats are correct
         searchStats1.add(searchStats2);
@@ -63,21 +72,59 @@ public void testShardLevelSearchGroupStats() throws Exception {
         // adding again would then return wrong search stats (would return 4! instead of 3)
         searchStats1.add(searchStats2);
         assertStats(groupStats1.get("group1"), 3);
+
+        long paramValue = randomIntBetween(2, 50);
+
+        // Testing for request stats
+        SearchRequestStats testRequestStats = new SearchRequestStats();
+        SearchPhaseContext ctx = mock(SearchPhaseContext.class);
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            SearchPhase mockSearchPhase = mock(SearchPhase.class);
+            when(ctx.getCurrentPhase()).thenReturn(mockSearchPhase);
+            when(mockSearchPhase.getStartTimeInNanos()).thenReturn(System.nanoTime() - TimeUnit.SECONDS.toNanos(paramValue));
+            when(mockSearchPhase.getSearchPhaseName()).thenReturn(searchPhaseName);
+            for (int iterator = 0; iterator < paramValue; iterator++) {
+                testRequestStats.onPhaseStart(ctx);
+                testRequestStats.onPhaseEnd(ctx);
+            }
+        }
+        searchStats1.setSearchRequestStats(testRequestStats);
+        for (SearchPhaseName searchPhaseName : SearchPhaseName.values()) {
+            assertEquals(
+                0,
+                searchStats1.getTotal().getRequestStatsLongHolder().getRequestStatsHolder().get(searchPhaseName.getName()).current
+            );
+            assertEquals(
+                paramValue,
+                searchStats1.getTotal().getRequestStatsLongHolder().getRequestStatsHolder().get(searchPhaseName.getName()).total
+            );
+            assertThat(
+                searchStats1.getTotal().getRequestStatsLongHolder().getRequestStatsHolder().get(searchPhaseName.getName()).timeInMillis,
+                greaterThanOrEqualTo(paramValue)
+            );
+        }
     }
 
     private static void assertStats(Stats stats, long equalTo) {
         assertEquals(equalTo, stats.getQueryCount());
         assertEquals(equalTo, stats.getQueryTimeInMillis());
         assertEquals(equalTo, stats.getQueryCurrent());
+        assertEquals(equalTo, stats.getConcurrentQueryCount());
+        assertEquals(equalTo, stats.getConcurrentQueryTimeInMillis());
+        assertEquals(equalTo, stats.getConcurrentQueryCurrent());
         assertEquals(equalTo, stats.getFetchCount());
         assertEquals(equalTo, stats.getFetchTimeInMillis());
         assertEquals(equalTo, stats.getFetchCurrent());
         assertEquals(equalTo, stats.getScrollCount());
         assertEquals(equalTo, stats.getScrollTimeInMillis());
         assertEquals(equalTo, stats.getScrollCurrent());
+        assertEquals(equalTo, stats.getPitCount());
+        assertEquals(equalTo, stats.getPitTimeInMillis());
+        assertEquals(equalTo, stats.getPitCurrent());
         assertEquals(equalTo, stats.getSuggestCount());
         assertEquals(equalTo, stats.getSuggestTimeInMillis());
         assertEquals(equalTo, stats.getSuggestCurrent());
+        // avg_concurrency is not summed up across stats
+        assertEquals(1, stats.getConcurrentAvgSliceCount(), 0);
     }
-
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/GlobalCheckpointSyncActionTests.java b/server/src/test/java/org/opensearch/index/seqno/GlobalCheckpointSyncActionTests.java
index 1e20c2e948f6e..8363ea3757a2b 100644
--- a/server/src/test/java/org/opensearch/index/seqno/GlobalCheckpointSyncActionTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/GlobalCheckpointSyncActionTests.java
@@ -34,16 +34,18 @@
 
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
+import org.opensearch.action.support.replication.ReplicationMode;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -77,7 +79,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -152,4 +155,59 @@ public void testTranslogSyncAfterGlobalCheckpointSync() throws Exception {
         }
     }
 
+    public void testGetReplicationModeWithRemoteTranslog() {
+        final GlobalCheckpointSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        final GlobalCheckpointSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private GlobalCheckpointSyncAction createAction() {
+        final IndicesService indicesService = mock(IndicesService.class);
+        return new GlobalCheckpointSyncAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            indicesService,
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet())
+        );
+    }
+
+    public void testMayBeSyncTranslogWithRemoteTranslog() throws Exception {
+        final GlobalCheckpointSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        final GlobalCheckpointSyncAction.Request primaryRequest = new GlobalCheckpointSyncAction.Request(indexShard.shardId());
+        final long globalCheckpoint = randomIntBetween(Math.toIntExact(SequenceNumbers.NO_OPS_PERFORMED), Integer.MAX_VALUE);
+        when(indexShard.getLastKnownGlobalCheckpoint()).thenReturn(globalCheckpoint);
+        when(indexShard.getLastSyncedGlobalCheckpoint()).thenReturn(globalCheckpoint - 1);
+        when(indexShard.getTranslogDurability()).thenReturn(Translog.Durability.REQUEST);
+
+        action.shardOperationOnPrimary(primaryRequest, indexShard, ActionTestUtils.assertNoFailureListener(r -> {}));
+        verify(indexShard, never()).sync();
+    }
+
+    public void testMayBeSyncTranslogWithLocalTranslog() throws Exception {
+        final GlobalCheckpointSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        final GlobalCheckpointSyncAction.Request primaryRequest = new GlobalCheckpointSyncAction.Request(indexShard.shardId());
+        final long globalCheckpoint = randomIntBetween(Math.toIntExact(SequenceNumbers.NO_OPS_PERFORMED), Integer.MAX_VALUE);
+        when(indexShard.getLastKnownGlobalCheckpoint()).thenReturn(globalCheckpoint);
+        when(indexShard.getLastSyncedGlobalCheckpoint()).thenReturn(globalCheckpoint - 1);
+        when(indexShard.getTranslogDurability()).thenReturn(Translog.Durability.REQUEST);
+
+        action.shardOperationOnPrimary(primaryRequest, indexShard, ActionTestUtils.assertNoFailureListener(r -> {}));
+        verify(indexShard).sync();
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/LocalCheckpointTrackerTests.java b/server/src/test/java/org/opensearch/index/seqno/LocalCheckpointTrackerTests.java
index bcb178e05065c..88c5e2b49b900 100644
--- a/server/src/test/java/org/opensearch/index/seqno/LocalCheckpointTrackerTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/LocalCheckpointTrackerTests.java
@@ -172,7 +172,7 @@ public void testSimpleOverFlow() {
         assertThat(tracker.processedCheckpoint.get(), equalTo(maxOps - 1L));
         assertThat(tracker.processedSeqNo.size(), equalTo(aligned ? 0 : 1));
         if (aligned == false) {
-            assertThat(tracker.processedSeqNo.keys().iterator().next().value, equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
+            assertThat(tracker.processedSeqNo.keySet().iterator().next(), equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
         }
         assertThat(tracker.hasProcessed(randomFrom(seqNoList)), equalTo(true));
         final long notCompletedSeqNo = randomValueOtherThanMany(seqNoList::contains, OpenSearchTestCase::randomNonNegativeLong);
@@ -218,7 +218,7 @@ protected void doRun() throws Exception {
         assertThat(tracker.getProcessedCheckpoint(), equalTo(maxOps - 1L));
         assertThat(tracker.processedSeqNo.size(), is(oneOf(0, 1)));
         if (tracker.processedSeqNo.size() == 1) {
-            assertThat(tracker.processedSeqNo.keys().iterator().next().value, equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
+            assertThat(tracker.processedSeqNo.keySet().iterator().next(), equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
         }
     }
 
@@ -272,7 +272,7 @@ protected void doRun() throws Exception {
         assertThat(tracker.hasProcessed(randomLongBetween(maxOps, Long.MAX_VALUE)), equalTo(false));
         assertThat(tracker.processedSeqNo.size(), is(oneOf(0, 1)));
         if (tracker.processedSeqNo.size() == 1) {
-            assertThat(tracker.processedSeqNo.keys().iterator().next().value, equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
+            assertThat(tracker.processedSeqNo.keySet().iterator().next(), equalTo(tracker.processedCheckpoint.get() / BIT_SET_SIZE));
         }
     }
 
@@ -331,4 +331,24 @@ public void testContains() {
         final long seqNo = randomNonNegativeLong();
         assertThat(tracker.hasProcessed(seqNo), equalTo(seqNo <= localCheckpoint || seqNos.contains(seqNo)));
     }
+
+    public void testFastForwardProcessedSeqNo() {
+        // base case with no persistent checkpoint update
+        long seqNo1;
+        assertThat(tracker.getProcessedCheckpoint(), equalTo(SequenceNumbers.NO_OPS_PERFORMED));
+        seqNo1 = tracker.generateSeqNo();
+        assertThat(seqNo1, equalTo(0L));
+        tracker.fastForwardProcessedSeqNo(seqNo1);
+        assertThat(tracker.getProcessedCheckpoint(), equalTo(seqNo1));
+
+        // idempotent case
+        tracker.fastForwardProcessedSeqNo(seqNo1);
+        assertThat(tracker.getProcessedCheckpoint(), equalTo(0L));
+        assertThat(tracker.hasProcessed(0L), equalTo(true));
+
+        tracker.fastForwardProcessedSeqNo(-1);
+        assertThat(tracker.getProcessedCheckpoint(), equalTo(0L));
+        assertThat(tracker.hasProcessed(0L), equalTo(true));
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseExpiryTests.java b/server/src/test/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseExpiryTests.java
index 5a8b04bce24ca..ca80c7b9c4884 100644
--- a/server/src/test/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseExpiryTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/PeerRecoveryRetentionLeaseExpiryTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
@@ -39,9 +38,10 @@
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.SafeCommitInfo;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.IndexSettingsModule;
 import org.junit.Before;
 
@@ -95,7 +95,7 @@ public void setUpReplicationTracker() throws InterruptedException {
             (leases, listener) -> {},
             () -> safeCommitInfo
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             1L,
             Collections.singleton(primaryAllocationId.getId()),
             routingTable(Collections.emptySet(), primaryAllocationId)
@@ -107,7 +107,7 @@ public void setUpReplicationTracker() throws InterruptedException {
             Collections.singleton(replicaAllocationId),
             primaryAllocationId
         );
-        replicationTracker.updateFromMaster(2L, Collections.singleton(primaryAllocationId.getId()), routingTableWithReplica);
+        replicationTracker.updateFromClusterManager(2L, Collections.singleton(primaryAllocationId.getId()), routingTableWithReplica);
         replicationTracker.addPeerRecoveryRetentionLease(
             routingTableWithReplica.getByAllocationId(replicaAllocationId.getId()).currentNodeId(),
             randomCheckpoint(),
@@ -127,7 +127,7 @@ private void startReplica() {
         final IndexShardRoutingTable.Builder builder = new IndexShardRoutingTable.Builder(replicationTracker.routingTable);
         builder.removeShard(replicaShardRouting);
         builder.addShard(replicaShardRouting.moveToStarted());
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             replicationTracker.appliedClusterStateVersion + 1,
             replicationTracker.routingTable.shards().stream().map(sr -> sr.allocationId().getId()).collect(Collectors.toSet()),
             builder.build()
diff --git a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerRetentionLeaseTests.java b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerRetentionLeaseTests.java
index d94c1b919ad71..3cd60ac973709 100644
--- a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerRetentionLeaseTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerRetentionLeaseTests.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.gateway.WriteStateException;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.IndexSettingsModule;
 
 import java.io.IOException;
@@ -86,7 +86,7 @@ public void testAddOrRenewRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -134,7 +134,7 @@ public void testAddDuplicateRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -166,7 +166,7 @@ public void testRenewNotFoundRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -205,7 +205,7 @@ public void testAddRetentionLeaseCausesRetentionLeaseSync() {
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
         reference.set(replicationTracker);
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -243,7 +243,7 @@ public void testRemoveRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -308,7 +308,7 @@ public void testCloneRetentionLease() {
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
         replicationTrackerRef.set(replicationTracker);
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -353,7 +353,7 @@ public void testCloneNonexistentRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -382,7 +382,7 @@ public void testCloneDuplicateRetentionLease() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -415,7 +415,7 @@ public void testRemoveNotFound() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -454,7 +454,7 @@ public void testRemoveRetentionLeaseCausesRetentionLeaseSync() {
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
         reference.set(replicationTracker);
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -506,7 +506,7 @@ private void runExpirationTest(final boolean primaryMode) {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -585,7 +585,7 @@ public void testReplicaIgnoresOlderRetentionLeasesVersion() {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -638,7 +638,7 @@ public void testLoadAndPersistRetentionLeases() throws IOException {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -673,7 +673,7 @@ public void testUnnecessaryPersistenceOfRetentionLeases() throws IOException {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -726,7 +726,7 @@ public void testPersistRetentionLeasesUnderConcurrency() throws IOException {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
@@ -790,7 +790,7 @@ public void testRenewLeaseWithLowerRetainingSequenceNumber() throws Exception {
             (leases, listener) -> {},
             OPS_BASED_RECOVERY_ALWAYS_REASONABLE
         );
-        replicationTracker.updateFromMaster(
+        replicationTracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(allocationId.getId()),
             routingTable(Collections.emptySet(), allocationId)
diff --git a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTestCase.java b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTestCase.java
index 34a2d1189d234..e61d27695a5e5 100644
--- a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTestCase.java
+++ b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTestCase.java
@@ -38,11 +38,12 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.SafeCommitInfo;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.Collections;
 import java.util.Set;
 import java.util.function.LongConsumer;
 import java.util.function.LongSupplier;
@@ -55,12 +56,13 @@ public abstract class ReplicationTrackerTestCase extends OpenSearchTestCase {
     ReplicationTracker newTracker(
         final AllocationId allocationId,
         final LongConsumer updatedGlobalCheckpoint,
-        final LongSupplier currentTimeMillisSupplier
+        final LongSupplier currentTimeMillisSupplier,
+        final Settings settings
     ) {
         return new ReplicationTracker(
             new ShardId("test", "_na_", 0),
             allocationId.getId(),
-            IndexSettingsModule.newIndexSettings("test", Settings.EMPTY),
+            IndexSettingsModule.newIndexSettings("test", settings),
             randomNonNegativeLong(),
             UNASSIGNED_SEQ_NO,
             updatedGlobalCheckpoint,
@@ -70,6 +72,14 @@ ReplicationTracker newTracker(
         );
     }
 
+    ReplicationTracker newTracker(
+        final AllocationId allocationId,
+        final LongConsumer updatedGlobalCheckpoint,
+        final LongSupplier currentTimeMillisSupplier
+    ) {
+        return newTracker(allocationId, updatedGlobalCheckpoint, currentTimeMillisSupplier, Settings.EMPTY);
+    }
+
     static final Supplier<SafeCommitInfo> OPS_BASED_RECOVERY_ALWAYS_REASONABLE = () -> SafeCommitInfo.EMPTY;
 
     static String nodeIdFromAllocationId(final AllocationId allocationId) {
@@ -77,6 +87,14 @@ static String nodeIdFromAllocationId(final AllocationId allocationId) {
     }
 
     static IndexShardRoutingTable routingTable(final Set<AllocationId> initializingIds, final AllocationId primaryId) {
+        return routingTable(initializingIds, Collections.singleton(primaryId), primaryId);
+    }
+
+    static IndexShardRoutingTable routingTable(
+        final Set<AllocationId> initializingIds,
+        final Set<AllocationId> activeIds,
+        final AllocationId primaryId
+    ) {
         final ShardId shardId = new ShardId("test", "_na_", 0);
         final ShardRouting primaryShard = TestShardRouting.newShardRouting(
             shardId,
@@ -86,11 +104,17 @@ static IndexShardRoutingTable routingTable(final Set<AllocationId> initializingI
             ShardRoutingState.STARTED,
             primaryId
         );
-        return routingTable(initializingIds, primaryShard);
+        return routingTable(initializingIds, activeIds, primaryShard);
     }
 
-    static IndexShardRoutingTable routingTable(final Set<AllocationId> initializingIds, final ShardRouting primaryShard) {
+    static IndexShardRoutingTable routingTable(
+        final Set<AllocationId> initializingIds,
+        final Set<AllocationId> activeIds,
+        final ShardRouting primaryShard
+    ) {
+        assert initializingIds != null && activeIds != null;
         assert !initializingIds.contains(primaryShard.allocationId());
+        assert activeIds.contains(primaryShard.allocationId());
         final ShardId shardId = new ShardId("test", "_na_", 0);
         final IndexShardRoutingTable.Builder builder = new IndexShardRoutingTable.Builder(shardId);
         for (final AllocationId initializingId : initializingIds) {
@@ -105,6 +129,21 @@ static IndexShardRoutingTable routingTable(final Set<AllocationId> initializingI
                 )
             );
         }
+        for (final AllocationId activeId : activeIds) {
+            if (activeId.equals(primaryShard.allocationId())) {
+                continue;
+            }
+            builder.addShard(
+                TestShardRouting.newShardRouting(
+                    shardId,
+                    nodeIdFromAllocationId(activeId),
+                    null,
+                    false,
+                    ShardRoutingState.STARTED,
+                    activeId
+                )
+            );
+        }
 
         builder.addShard(primaryShard);
 
diff --git a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTests.java b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTests.java
index 8fe8a13de9910..28c95ddf13fc4 100644
--- a/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTests.java
@@ -32,8 +32,10 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.util.Version;
 import org.opensearch.action.support.replication.ReplicationResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
@@ -42,11 +44,17 @@
 import org.opensearch.common.Randomness;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.indices.replication.common.SegmentReplicationLagTimer;
 import org.opensearch.test.IndexSettingsModule;
 
 import java.io.IOException;
@@ -72,6 +80,7 @@
 import java.util.stream.Stream;
 
 import static java.util.Collections.emptySet;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
 import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 import static org.hamcrest.Matchers.equalTo;
@@ -137,7 +146,7 @@ public void testGlobalCheckpointUpdate() {
             logger.info("  - [{}], local checkpoint [{}], [{}]", aId, allocations.get(aId), type);
         });
 
-        tracker.updateFromMaster(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         assertThat(tracker.getReplicationGroup().getReplicationTargets().size(), equalTo(1));
         initializing.forEach(aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED));
@@ -160,14 +169,14 @@ public void testGlobalCheckpointUpdate() {
         // now insert an unknown active/insync id , the checkpoint shouldn't change but a refresh should be requested.
         final AllocationId extraId = AllocationId.newInitializing();
 
-        // first check that adding it without the master blessing doesn't change anything.
+        // first check that adding it without the cluster-manager blessing doesn't change anything.
         updateLocalCheckpoint(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4));
         assertNull(tracker.checkpoints.get(extraId.getId()));
         expectThrows(IllegalStateException.class, () -> tracker.initiateTracking(extraId.getId()));
 
         Set<AllocationId> newInitializing = new HashSet<>(initializing);
         newInitializing.add(extraId);
-        tracker.updateFromMaster(initialClusterStateVersion + 1, ids(active), routingTable(newInitializing, primaryId));
+        tracker.updateFromClusterManager(initialClusterStateVersion + 1, ids(active), routingTable(newInitializing, primaryId));
 
         addPeerRecoveryRetentionLease(tracker, extraId);
         tracker.initiateTracking(extraId.getId());
@@ -208,7 +217,7 @@ public void testMarkAllocationIdAsInSync() throws Exception {
         final AllocationId primaryId = active.iterator().next();
         final AllocationId replicaId = initializing.iterator().next();
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
         final long localCheckpoint = randomLongBetween(0, Long.MAX_VALUE - 1);
         tracker.activatePrimaryMode(localCheckpoint);
         addPeerRecoveryRetentionLease(tracker, replicaId);
@@ -249,7 +258,7 @@ public void testMissingActiveIdsPreventAdvance() {
         assigned.putAll(initializing);
         AllocationId primaryId = active.keySet().iterator().next();
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         randomSubsetOf(initializing.keySet()).forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
         final AllocationId missingActiveID = randomFrom(active.keySet());
@@ -275,7 +284,7 @@ public void testMissingInSyncIdsPreventAdvance() {
 
         AllocationId primaryId = active.keySet().iterator().next();
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         randomSubsetOf(randomIntBetween(1, initializing.size() - 1), initializing.keySet()).forEach(
             aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED)
@@ -292,13 +301,13 @@ public void testMissingInSyncIdsPreventAdvance() {
         assertThat(updatedGlobalCheckpoint.get(), not(equalTo(UNASSIGNED_SEQ_NO)));
     }
 
-    public void testInSyncIdsAreIgnoredIfNotValidatedByMaster() {
+    public void testInSyncIdsAreIgnoredIfNotValidatedByClusterManager() {
         final Map<AllocationId, Long> active = randomAllocationsWithLocalCheckpoints(1, 5);
         final Map<AllocationId, Long> initializing = randomAllocationsWithLocalCheckpoints(1, 5);
         final Map<AllocationId, Long> nonApproved = randomAllocationsWithLocalCheckpoints(1, 5);
         final AllocationId primaryId = active.keySet().iterator().next();
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         initializing.keySet().forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
         nonApproved.keySet()
@@ -313,7 +322,7 @@ public void testInSyncIdsAreIgnoredIfNotValidatedByMaster() {
         assertThat(tracker.getGlobalCheckpoint(), not(equalTo(UNASSIGNED_SEQ_NO)));
     }
 
-    public void testInSyncIdsAreRemovedIfNotValidatedByMaster() {
+    public void testInSyncIdsAreRemovedIfNotValidatedByClusterManager() {
         final long initialClusterStateVersion = randomNonNegativeLong();
         final Map<AllocationId, Long> activeToStay = randomAllocationsWithLocalCheckpoints(1, 5);
         final Map<AllocationId, Long> initializingToStay = randomAllocationsWithLocalCheckpoints(1, 5);
@@ -335,7 +344,7 @@ public void testInSyncIdsAreRemovedIfNotValidatedByMaster() {
             allocations.putAll(initializingToBeRemoved);
         }
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         if (randomBoolean()) {
             initializingToStay.keySet().forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
@@ -348,7 +357,7 @@ public void testInSyncIdsAreRemovedIfNotValidatedByMaster() {
 
         // now remove shards
         if (randomBoolean()) {
-            tracker.updateFromMaster(
+            tracker.updateFromClusterManager(
                 initialClusterStateVersion + 1,
                 ids(activeToStay.keySet()),
                 routingTable(initializingToStay.keySet(), primaryId)
@@ -356,7 +365,7 @@ public void testInSyncIdsAreRemovedIfNotValidatedByMaster() {
             allocations.forEach((aid, ckp) -> updateLocalCheckpoint(tracker, aid.getId(), ckp + 10L));
         } else {
             allocations.forEach((aid, ckp) -> updateLocalCheckpoint(tracker, aid.getId(), ckp + 10L));
-            tracker.updateFromMaster(
+            tracker.updateFromClusterManager(
                 initialClusterStateVersion + 2,
                 ids(activeToStay.keySet()),
                 routingTable(initializingToStay.keySet(), primaryId)
@@ -378,7 +387,7 @@ public void testWaitForAllocationIdToBeInSync() throws Exception {
         final AllocationId trackingAllocationId = AllocationId.newInitializing();
         final ReplicationTracker tracker = newTracker(inSyncAllocationId);
         final long clusterStateVersion = randomNonNegativeLong();
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             clusterStateVersion,
             Collections.singleton(inSyncAllocationId.getId()),
             routingTable(Collections.singleton(trackingAllocationId), inSyncAllocationId)
@@ -421,8 +430,8 @@ public void testWaitForAllocationIdToBeInSync() throws Exception {
             assertTrue(complete.get());
             assertTrue(tracker.getTrackedLocalCheckpointForShard(trackingAllocationId.getId()).inSync);
         } else {
-            // master changes its mind and cancels the allocation
-            tracker.updateFromMaster(
+            // cluster-manager changes its mind and cancels the allocation
+            tracker.updateFromClusterManager(
                 clusterStateVersion + 1,
                 Collections.singleton(inSyncAllocationId.getId()),
                 routingTable(emptySet(), inSyncAllocationId)
@@ -437,6 +446,10 @@ public void testWaitForAllocationIdToBeInSync() throws Exception {
 
     private AtomicLong updatedGlobalCheckpoint = new AtomicLong(UNASSIGNED_SEQ_NO);
 
+    private ReplicationTracker newTracker(final AllocationId allocationId, Settings settings) {
+        return newTracker(allocationId, updatedGlobalCheckpoint::set, () -> 0L, settings);
+    }
+
     private ReplicationTracker newTracker(final AllocationId allocationId) {
         return newTracker(allocationId, updatedGlobalCheckpoint::set, () -> 0L);
     }
@@ -449,7 +462,7 @@ public void testWaitForAllocationIdToBeInSyncCanBeInterrupted() throws BrokenBar
         final AllocationId inSyncAllocationId = AllocationId.newInitializing();
         final AllocationId trackingAllocationId = AllocationId.newInitializing();
         final ReplicationTracker tracker = newTracker(inSyncAllocationId);
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(inSyncAllocationId.getId()),
             routingTable(Collections.singleton(trackingAllocationId), inSyncAllocationId)
@@ -492,7 +505,7 @@ public void testWaitForAllocationIdToBeInSyncCanBeInterrupted() throws BrokenBar
         thread.join();
     }
 
-    public void testUpdateAllocationIdsFromMaster() throws Exception {
+    public void testUpdateAllocationIdsFromClusterManager() throws Exception {
         final long initialClusterStateVersion = randomNonNegativeLong();
         final int numberOfActiveAllocationsIds = randomIntBetween(2, 16);
         final int numberOfInitializingIds = randomIntBetween(2, 16);
@@ -505,7 +518,7 @@ public void testUpdateAllocationIdsFromMaster() throws Exception {
         AllocationId primaryId = activeAllocationIds.iterator().next();
         IndexShardRoutingTable routingTable = routingTable(initializingIds, primaryId);
         final ReplicationTracker tracker = newTracker(primaryId);
-        tracker.updateFromMaster(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         assertThat(tracker.getReplicationGroup().getInSyncAllocationIds(), equalTo(ids(activeAllocationIds)));
         assertThat(tracker.getReplicationGroup().getRoutingTable(), equalTo(routingTable));
@@ -539,7 +552,7 @@ public void testUpdateAllocationIdsFromMaster() throws Exception {
             .filter(a -> !removingInitializingAllocationIds.contains(a))
             .collect(Collectors.toSet());
         routingTable = routingTable(newInitializingAllocationIds, primaryId);
-        tracker.updateFromMaster(initialClusterStateVersion + 1, ids(newActiveAllocationIds), routingTable);
+        tracker.updateFromClusterManager(initialClusterStateVersion + 1, ids(newActiveAllocationIds), routingTable);
         assertTrue(newActiveAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
         assertTrue(removingActiveAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()) == null));
         assertTrue(newInitializingAllocationIds.stream().noneMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
@@ -555,7 +568,7 @@ public void testUpdateAllocationIdsFromMaster() throws Exception {
          * than we have been using above ensures that we can not collide with a previous allocation ID
          */
         newInitializingAllocationIds.add(AllocationId.newInitializing());
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             initialClusterStateVersion + 2,
             ids(newActiveAllocationIds),
             routingTable(newInitializingAllocationIds, primaryId)
@@ -607,7 +620,7 @@ public void testUpdateAllocationIdsFromMaster() throws Exception {
         // using a different length than we have been using above ensures that we can not collide with a previous allocation ID
         final AllocationId newSyncingAllocationId = AllocationId.newInitializing();
         newInitializingAllocationIds.add(newSyncingAllocationId);
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             initialClusterStateVersion + 3,
             ids(newActiveAllocationIds),
             routingTable(newInitializingAllocationIds, primaryId)
@@ -645,11 +658,11 @@ public void testUpdateAllocationIdsFromMaster() throws Exception {
         assertTrue(tracker.getTrackedLocalCheckpointForShard(newSyncingAllocationId.getId()).inSync);
 
         /*
-         * The new in-sync allocation ID is in the in-sync set now yet the master does not know this; the allocation ID should still be in
+         * The new in-sync allocation ID is in the in-sync set now yet the cluster-manager does not know this; the allocation ID should still be in
          * the in-sync set even if we receive a cluster state update that does not reflect this.
          *
          */
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             initialClusterStateVersion + 4,
             ids(newActiveAllocationIds),
             routingTable(newInitializingAllocationIds, primaryId)
@@ -678,7 +691,7 @@ public void testRaceUpdatingGlobalCheckpoint() throws InterruptedException, Brok
 
         final int activeLocalCheckpoint = randomIntBetween(0, Integer.MAX_VALUE - 1);
         final ReplicationTracker tracker = newTracker(active);
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(active.getId()),
             routingTable(Collections.singleton(initializing), active)
@@ -907,7 +920,7 @@ public void testIllegalStateExceptionIfUnknownAllocationId() {
         final AllocationId active = AllocationId.newInitializing();
         final AllocationId initializing = AllocationId.newInitializing();
         final ReplicationTracker tracker = newTracker(active);
-        tracker.updateFromMaster(
+        tracker.updateFromClusterManager(
             randomNonNegativeLong(),
             Collections.singleton(active.getId()),
             routingTable(Collections.singleton(initializing), active)
@@ -938,7 +951,7 @@ public Set<AllocationId> initializingIds() {
         }
 
         public void apply(ReplicationTracker gcp) {
-            gcp.updateFromMaster(version, ids(inSyncIds), routingTable);
+            gcp.updateFromClusterManager(version, ids(inSyncIds), routingTable);
         }
     }
 
@@ -966,7 +979,11 @@ private static FakeClusterState initialState() {
             relocatingId
         );
 
-        return new FakeClusterState(initialClusterStateVersion, activeAllocationIds, routingTable(initializingAllocationIds, primaryShard));
+        return new FakeClusterState(
+            initialClusterStateVersion,
+            activeAllocationIds,
+            routingTable(initializingAllocationIds, Collections.singleton(primaryShard.allocationId()), primaryShard)
+        );
     }
 
     private static void randomLocalCheckpointUpdate(ReplicationTracker gcp) {
@@ -1007,6 +1024,7 @@ private static FakeClusterState randomUpdateClusterState(Set<String> allocationI
             remainingInSyncIds.isEmpty() ? clusterState.inSyncIds : remainingInSyncIds,
             routingTable(
                 Sets.difference(Sets.union(initializingIdsExceptRelocationTargets, initializingIdsToAdd), initializingIdsToRemove),
+                Collections.singleton(clusterState.routingTable.primaryShard().allocationId()),
                 clusterState.routingTable.primaryShard()
             )
         );
@@ -1046,9 +1064,20 @@ private static void markAsTrackingAndInSyncQuietly(
         final ReplicationTracker tracker,
         final String allocationId,
         final long localCheckpoint
+    ) {
+        markAsTrackingAndInSyncQuietly(tracker, allocationId, localCheckpoint, true);
+    }
+
+    private static void markAsTrackingAndInSyncQuietly(
+        final ReplicationTracker tracker,
+        final String allocationId,
+        final long localCheckpoint,
+        final boolean addPRRL
     ) {
         try {
-            addPeerRecoveryRetentionLease(tracker, allocationId);
+            if (addPRRL) {
+                addPeerRecoveryRetentionLease(tracker, allocationId);
+            }
             tracker.initiateTracking(allocationId);
             tracker.markAllocationIdAsInSync(allocationId, localCheckpoint);
         } catch (final InterruptedException e) {
@@ -1114,7 +1143,7 @@ public void testPeerRecoveryRetentionLeaseCreationAndRenewal() {
         tracker.updateRetentionLeasesOnReplica(new RetentionLeases(randomNonNegativeLong(), randomNonNegativeLong(), initialLeases));
 
         IndexShardRoutingTable routingTable = routingTable(initializingAllocationIds, primaryId);
-        tracker.updateFromMaster(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
         tracker.activatePrimaryMode(NO_OPS_PERFORMED);
         assertTrue(
             "primary's retention lease should exist",
@@ -1184,7 +1213,7 @@ public void testPeerRecoveryRetentionLeaseCreationAndRenewal() {
         routingTable = routingTableBuilder.build();
         activeAllocationIds.addAll(initializingAllocationIds);
 
-        tracker.updateFromMaster(initialClusterStateVersion + randomLongBetween(1, 10), ids(activeAllocationIds), routingTable);
+        tracker.updateFromClusterManager(initialClusterStateVersion + randomLongBetween(1, 10), ids(activeAllocationIds), routingTable);
 
         assertAsTimePasses.accept(() -> {
             // Leases still don't expire
@@ -1252,4 +1281,910 @@ public void testPeerRecoveryRetentionLeaseCreationAndRenewal() {
         );
     }
 
+    /**
+     * This test checks that the global checkpoint update mechanism is honored and relies only on the shards that have
+     * translog stored locally.
+     */
+    public void testGlobalCheckpointUpdateWithRemoteTranslogEnabled() {
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        Map<AllocationId, Long> activeWithCheckpoints = randomAllocationsWithLocalCheckpoints(1, 5);
+        Set<AllocationId> active = new HashSet<>(activeWithCheckpoints.keySet());
+        Map<AllocationId, Long> allocations = new HashMap<>(activeWithCheckpoints);
+        Map<AllocationId, Long> initializingWithCheckpoints = randomAllocationsWithLocalCheckpoints(0, 5);
+        Set<AllocationId> initializing = new HashSet<>(initializingWithCheckpoints.keySet());
+        allocations.putAll(initializingWithCheckpoints);
+        assertThat(allocations.size(), equalTo(active.size() + initializing.size()));
+
+        final AllocationId primaryId = active.iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        assertThat(tracker.getGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
+
+        long primaryLocalCheckpoint = activeWithCheckpoints.get(primaryId);
+
+        logger.info("--> using allocations");
+        allocations.keySet().forEach(aId -> {
+            final String type;
+            if (active.contains(aId)) {
+                type = "active";
+            } else if (initializing.contains(aId)) {
+                type = "init";
+            } else {
+                throw new IllegalStateException(aId + " not found in any map");
+            }
+            logger.info("  - [{}], local checkpoint [{}], [{}]", aId, allocations.get(aId), type);
+        });
+
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        assertThat(tracker.getReplicationGroup().getReplicationTargets().size(), equalTo(1));
+        initializing.forEach(aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED, false));
+        assertThat(tracker.getReplicationGroup().getReplicationTargets().size(), equalTo(1 + initializing.size()));
+        Set<AllocationId> replicationTargets = tracker.getReplicationGroup()
+            .getReplicationTargets()
+            .stream()
+            .map(ShardRouting::allocationId)
+            .collect(Collectors.toSet());
+        assertTrue(replicationTargets.containsAll(initializing));
+        allocations.keySet().forEach(aId -> updateLocalCheckpoint(tracker, aId.getId(), allocations.get(aId)));
+
+        assertEquals(tracker.getGlobalCheckpoint(), primaryLocalCheckpoint);
+
+        // increment checkpoints
+        active.forEach(aId -> allocations.put(aId, allocations.get(aId) + 1 + randomInt(4)));
+        initializing.forEach(aId -> allocations.put(aId, allocations.get(aId) + 1 + randomInt(4)));
+        allocations.keySet().forEach(aId -> updateLocalCheckpoint(tracker, aId.getId(), allocations.get(aId)));
+
+        final long minLocalCheckpointAfterUpdates = allocations.values().stream().min(Long::compareTo).orElse(UNASSIGNED_SEQ_NO);
+
+        // now insert an unknown active/insync id , the checkpoint shouldn't change but a refresh should be requested.
+        final AllocationId extraId = AllocationId.newInitializing();
+
+        // first check that adding it without the cluster-manager blessing doesn't change anything.
+        updateLocalCheckpoint(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4));
+        assertNull(tracker.checkpoints.get(extraId.getId()));
+        expectThrows(IllegalStateException.class, () -> tracker.initiateTracking(extraId.getId()));
+
+        Set<AllocationId> newInitializing = new HashSet<>(initializing);
+        newInitializing.add(extraId);
+        tracker.updateFromClusterManager(initialClusterStateVersion + 1, ids(active), routingTable(newInitializing, primaryId));
+
+        tracker.initiateTracking(extraId.getId());
+
+        // now notify for the new id
+        if (randomBoolean()) {
+            updateLocalCheckpoint(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4));
+            markAsTrackingAndInSyncQuietly(tracker, extraId.getId(), randomInt((int) minLocalCheckpointAfterUpdates), false);
+        } else {
+            markAsTrackingAndInSyncQuietly(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4), false);
+        }
+    }
+
+    public void testUpdateFromClusterManagerWithRemoteTranslogEnabled() {
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        Map<AllocationId, Long> activeWithCheckpoints = randomAllocationsWithLocalCheckpoints(2, 5);
+        Set<AllocationId> active = new HashSet<>(activeWithCheckpoints.keySet());
+        Map<AllocationId, Long> allocations = new HashMap<>(activeWithCheckpoints);
+        Map<AllocationId, Long> initializingWithCheckpoints = randomAllocationsWithLocalCheckpoints(0, 5);
+        Set<AllocationId> initializing = new HashSet<>(initializingWithCheckpoints.keySet());
+        allocations.putAll(initializingWithCheckpoints);
+        assertThat(allocations.size(), equalTo(active.size() + initializing.size()));
+
+        final AllocationId primaryId = active.iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        assertThat(tracker.getGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
+
+        long primaryLocalCheckpoint = activeWithCheckpoints.get(primaryId);
+
+        logger.info("--> using allocations");
+        allocations.keySet().forEach(aId -> {
+            final String type;
+            if (active.contains(aId)) {
+                type = "active";
+            } else if (initializing.contains(aId)) {
+                type = "init";
+            } else {
+                throw new IllegalStateException(aId + " not found in any map");
+            }
+            logger.info("  - [{}], local checkpoint [{}], [{}]", aId, allocations.get(aId), type);
+        });
+
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, active, primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        assertEquals(tracker.getReplicationGroup().getReplicationTargets().size(), active.size());
+        initializing.forEach(aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED, false));
+        assertEquals(tracker.getReplicationGroup().getReplicationTargets().size(), active.size() + initializing.size());
+        Set<AllocationId> replicationTargets = tracker.getReplicationGroup()
+            .getReplicationTargets()
+            .stream()
+            .map(ShardRouting::allocationId)
+            .collect(Collectors.toSet());
+        assertTrue(replicationTargets.containsAll(initializing));
+        assertTrue(replicationTargets.containsAll(active));
+        allocations.keySet().forEach(aId -> updateLocalCheckpoint(tracker, aId.getId(), allocations.get(aId)));
+
+        assertEquals(tracker.getGlobalCheckpoint(), primaryLocalCheckpoint);
+
+        // increment checkpoints
+        active.forEach(aId -> allocations.put(aId, allocations.get(aId) + 1 + randomInt(4)));
+        initializing.forEach(aId -> allocations.put(aId, allocations.get(aId) + 1 + randomInt(4)));
+        allocations.keySet().forEach(aId -> updateLocalCheckpoint(tracker, aId.getId(), allocations.get(aId)));
+
+        final long minLocalCheckpointAfterUpdates = allocations.values().stream().min(Long::compareTo).orElse(UNASSIGNED_SEQ_NO);
+
+        // now insert an unknown active/insync id , the checkpoint shouldn't change but a refresh should be requested.
+        final AllocationId extraId = AllocationId.newInitializing();
+
+        // first check that adding it without the cluster-manager blessing doesn't change anything.
+        updateLocalCheckpoint(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4));
+        assertNull(tracker.checkpoints.get(extraId.getId()));
+        expectThrows(IllegalStateException.class, () -> tracker.initiateTracking(extraId.getId()));
+
+        Set<AllocationId> newInitializing = new HashSet<>(initializing);
+        newInitializing.add(extraId);
+        tracker.updateFromClusterManager(initialClusterStateVersion + 1, ids(active), routingTable(newInitializing, primaryId));
+
+        tracker.initiateTracking(extraId.getId());
+
+        // now notify for the new id
+        if (randomBoolean()) {
+            updateLocalCheckpoint(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4));
+            markAsTrackingAndInSyncQuietly(tracker, extraId.getId(), randomInt((int) minLocalCheckpointAfterUpdates), false);
+        } else {
+            markAsTrackingAndInSyncQuietly(tracker, extraId.getId(), minLocalCheckpointAfterUpdates + 1 + randomInt(4), false);
+        }
+    }
+
+    /**
+     * This test checks that updateGlobalCheckpointOnReplica with remote translog does not violate any of the invariants
+     */
+    public void testUpdateGlobalCheckpointOnReplicaWithRemoteTranslogEnabled() {
+        final AllocationId active = AllocationId.newInitializing();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(active, settings);
+        final long globalCheckpoint = randomLongBetween(NO_OPS_PERFORMED, Long.MAX_VALUE - 1);
+        tracker.updateGlobalCheckpointOnReplica(globalCheckpoint, "test");
+        assertEquals(updatedGlobalCheckpoint.get(), globalCheckpoint);
+        final long nonUpdate = randomLongBetween(NO_OPS_PERFORMED, globalCheckpoint);
+        updatedGlobalCheckpoint.set(UNASSIGNED_SEQ_NO);
+        tracker.updateGlobalCheckpointOnReplica(nonUpdate, "test");
+        assertEquals(updatedGlobalCheckpoint.get(), UNASSIGNED_SEQ_NO);
+        final long update = randomLongBetween(globalCheckpoint, Long.MAX_VALUE);
+        tracker.updateGlobalCheckpointOnReplica(update, "test");
+        assertEquals(updatedGlobalCheckpoint.get(), update);
+    }
+
+    public void testMarkAllocationIdAsInSyncWithRemoteTranslogEnabled() throws Exception {
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        Map<AllocationId, Long> activeWithCheckpoints = randomAllocationsWithLocalCheckpoints(1, 1);
+        Set<AllocationId> active = new HashSet<>(activeWithCheckpoints.keySet());
+        Map<AllocationId, Long> initializingWithCheckpoints = randomAllocationsWithLocalCheckpoints(1, 1);
+        Set<AllocationId> initializing = new HashSet<>(initializingWithCheckpoints.keySet());
+        final AllocationId primaryId = active.iterator().next();
+        final AllocationId replicaId = initializing.iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        final long localCheckpoint = randomLongBetween(0, Long.MAX_VALUE - 1);
+        tracker.activatePrimaryMode(localCheckpoint);
+        tracker.initiateTracking(replicaId.getId());
+        tracker.markAllocationIdAsInSync(replicaId.getId(), randomLongBetween(NO_OPS_PERFORMED, localCheckpoint - 1));
+        assertFalse(tracker.pendingInSync());
+        final long updatedLocalCheckpoint = randomLongBetween(1 + localCheckpoint, Long.MAX_VALUE);
+        updatedGlobalCheckpoint.set(UNASSIGNED_SEQ_NO);
+        tracker.updateLocalCheckpoint(primaryId.getId(), updatedLocalCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), updatedLocalCheckpoint);
+        tracker.updateLocalCheckpoint(replicaId.getId(), localCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), updatedLocalCheckpoint);
+        tracker.markAllocationIdAsInSync(replicaId.getId(), updatedLocalCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), updatedLocalCheckpoint);
+    }
+
+    public void testMissingActiveIdsDoesNotPreventAdvanceWithRemoteTranslogEnabled() {
+        final Map<AllocationId, Long> active = randomAllocationsWithLocalCheckpoints(2, 5);
+        final Map<AllocationId, Long> initializing = randomAllocationsWithLocalCheckpoints(0, 5);
+        final Map<AllocationId, Long> assigned = new HashMap<>();
+        assigned.putAll(active);
+        assigned.putAll(initializing);
+        AllocationId primaryId = active.keySet().iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        List<AllocationId> initializingRandomSubset = randomSubsetOf(initializing.keySet());
+        initializingRandomSubset.forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
+        final AllocationId missingActiveID = randomFrom(active.keySet());
+        assigned.entrySet()
+            .stream()
+            .filter(e -> !e.getKey().equals(missingActiveID))
+            .forEach(e -> updateLocalCheckpoint(tracker, e.getKey().getId(), e.getValue()));
+        long primaryLocalCheckpoint = active.get(primaryId);
+
+        assertEquals(1 + initializingRandomSubset.size(), tracker.getReplicationGroup().getReplicationTargets().size());
+        if (missingActiveID.equals(primaryId) == false) {
+            assertEquals(tracker.getGlobalCheckpoint(), primaryLocalCheckpoint);
+            assertEquals(updatedGlobalCheckpoint.get(), primaryLocalCheckpoint);
+        }
+        // now update all knowledge of all shards
+        assigned.forEach((aid, localCP) -> updateLocalCheckpoint(tracker, aid.getId(), 10 + localCP));
+        assertEquals(tracker.getGlobalCheckpoint(), 10 + primaryLocalCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), 10 + primaryLocalCheckpoint);
+    }
+
+    public void testMissingInSyncIdsDoesNotPreventAdvanceWithRemoteTranslogEnabled() {
+        final Map<AllocationId, Long> active = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> initializing = randomAllocationsWithLocalCheckpoints(2, 5);
+        logger.info("active: {}, initializing: {}", active, initializing);
+
+        AllocationId primaryId = active.keySet().iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        randomSubsetOf(randomIntBetween(1, initializing.size() - 1), initializing.keySet()).forEach(
+            aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED)
+        );
+        long primaryLocalCheckpoint = active.get(primaryId);
+
+        active.forEach((aid, localCP) -> updateLocalCheckpoint(tracker, aid.getId(), localCP));
+
+        assertEquals(tracker.getGlobalCheckpoint(), primaryLocalCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), primaryLocalCheckpoint);
+
+        // update again
+        initializing.forEach((aid, localCP) -> updateLocalCheckpoint(tracker, aid.getId(), localCP));
+        assertEquals(tracker.getGlobalCheckpoint(), primaryLocalCheckpoint);
+        assertEquals(updatedGlobalCheckpoint.get(), primaryLocalCheckpoint);
+    }
+
+    public void testInSyncIdsAreIgnoredIfNotValidatedByClusterManagerWithRemoteTranslogEnabled() {
+        final Map<AllocationId, Long> active = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> initializing = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> nonApproved = randomAllocationsWithLocalCheckpoints(1, 5);
+        final AllocationId primaryId = active.keySet().iterator().next();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        initializing.keySet().forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
+        nonApproved.keySet()
+            .forEach(
+                k -> expectThrows(IllegalStateException.class, () -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED))
+            );
+
+        List<Map<AllocationId, Long>> allocations = Arrays.asList(active, initializing, nonApproved);
+        Collections.shuffle(allocations, random());
+        allocations.forEach(a -> a.forEach((aid, localCP) -> updateLocalCheckpoint(tracker, aid.getId(), localCP)));
+
+        assertNotEquals(UNASSIGNED_SEQ_NO, tracker.getGlobalCheckpoint());
+    }
+
+    public void testInSyncIdsAreRemovedIfNotValidatedByClusterManagerWithRemoteTranslogEnabled() {
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        final Map<AllocationId, Long> activeToStay = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> initializingToStay = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> activeToBeRemoved = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Map<AllocationId, Long> initializingToBeRemoved = randomAllocationsWithLocalCheckpoints(1, 5);
+        final Set<AllocationId> active = Sets.union(activeToStay.keySet(), activeToBeRemoved.keySet());
+        final Set<AllocationId> initializing = Sets.union(initializingToStay.keySet(), initializingToBeRemoved.keySet());
+        final Map<AllocationId, Long> allocations = new HashMap<>();
+        final AllocationId primaryId = active.iterator().next();
+        if (activeToBeRemoved.containsKey(primaryId)) {
+            activeToStay.put(primaryId, activeToBeRemoved.remove(primaryId));
+        }
+        allocations.putAll(activeToStay);
+        if (randomBoolean()) {
+            allocations.putAll(activeToBeRemoved);
+        }
+        allocations.putAll(initializingToStay);
+        if (randomBoolean()) {
+            allocations.putAll(initializingToBeRemoved);
+        }
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(active), routingTable(initializing, primaryId));
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        if (randomBoolean()) {
+            initializingToStay.keySet().forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
+        } else {
+            initializing.forEach(k -> markAsTrackingAndInSyncQuietly(tracker, k.getId(), NO_OPS_PERFORMED));
+        }
+        if (randomBoolean()) {
+            allocations.forEach((aid, localCP) -> updateLocalCheckpoint(tracker, aid.getId(), localCP));
+        }
+
+        // now remove shards
+        if (randomBoolean()) {
+            tracker.updateFromClusterManager(
+                initialClusterStateVersion + 1,
+                ids(activeToStay.keySet()),
+                routingTable(initializingToStay.keySet(), primaryId)
+            );
+            allocations.forEach((aid, ckp) -> updateLocalCheckpoint(tracker, aid.getId(), ckp + 10L));
+        } else {
+            allocations.forEach((aid, ckp) -> updateLocalCheckpoint(tracker, aid.getId(), ckp + 10L));
+            tracker.updateFromClusterManager(
+                initialClusterStateVersion + 2,
+                ids(activeToStay.keySet()),
+                routingTable(initializingToStay.keySet(), primaryId)
+            );
+        }
+
+        final long checkpoint = activeToStay.get(primaryId) + 10;
+        assertEquals(tracker.getGlobalCheckpoint(), checkpoint);
+    }
+
+    public void testUpdateAllocationIdsFromClusterManagerWithRemoteTranslogEnabled() throws Exception {
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        final int numberOfActiveAllocationsIds = randomIntBetween(2, 16);
+        final int numberOfInitializingIds = randomIntBetween(2, 16);
+        final Tuple<Set<AllocationId>, Set<AllocationId>> activeAndInitializingAllocationIds = randomActiveAndInitializingAllocationIds(
+            numberOfActiveAllocationsIds,
+            numberOfInitializingIds
+        );
+        final Set<AllocationId> activeAllocationIds = activeAndInitializingAllocationIds.v1();
+        final Set<AllocationId> initializingIds = activeAndInitializingAllocationIds.v2();
+        AllocationId primaryId = activeAllocationIds.iterator().next();
+        IndexShardRoutingTable routingTable = routingTable(initializingIds, primaryId);
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        assertThat(tracker.getReplicationGroup().getInSyncAllocationIds(), equalTo(ids(activeAllocationIds)));
+        assertThat(tracker.getReplicationGroup().getRoutingTable(), equalTo(routingTable));
+
+        // first we assert that the in-sync and tracking sets are set up correctly
+        assertTrue(activeAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(
+            activeAllocationIds.stream()
+                .filter(a -> a.equals(primaryId) == false)
+                .allMatch(
+                    a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).getLocalCheckpoint() == SequenceNumbers.UNASSIGNED_SEQ_NO
+                )
+        );
+        assertTrue(initializingIds.stream().noneMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(
+            initializingIds.stream()
+                .filter(a -> a.equals(primaryId) == false)
+                .allMatch(
+                    a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).getLocalCheckpoint() == SequenceNumbers.UNASSIGNED_SEQ_NO
+                )
+        );
+
+        // now we will remove some allocation IDs from these and ensure that they propagate through
+        final Set<AllocationId> removingActiveAllocationIds = new HashSet<>(randomSubsetOf(activeAllocationIds));
+        removingActiveAllocationIds.remove(primaryId);
+        final Set<AllocationId> newActiveAllocationIds = activeAllocationIds.stream()
+            .filter(a -> !removingActiveAllocationIds.contains(a))
+            .collect(Collectors.toSet());
+        final List<AllocationId> removingInitializingAllocationIds = randomSubsetOf(initializingIds);
+        final Set<AllocationId> newInitializingAllocationIds = initializingIds.stream()
+            .filter(a -> !removingInitializingAllocationIds.contains(a))
+            .collect(Collectors.toSet());
+        routingTable = routingTable(newInitializingAllocationIds, primaryId);
+        tracker.updateFromClusterManager(initialClusterStateVersion + 1, ids(newActiveAllocationIds), routingTable);
+        assertTrue(newActiveAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(removingActiveAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()) == null));
+        assertTrue(newInitializingAllocationIds.stream().noneMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(removingInitializingAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()) == null));
+        assertThat(
+            tracker.getReplicationGroup().getInSyncAllocationIds(),
+            equalTo(ids(Sets.difference(Sets.union(activeAllocationIds, newActiveAllocationIds), removingActiveAllocationIds)))
+        );
+        assertThat(tracker.getReplicationGroup().getRoutingTable(), equalTo(routingTable));
+
+        /*
+         * Now we will add an allocation ID to each of active and initializing and ensure they propagate through. Using different lengths
+         * than we have been using above ensures that we can not collide with a previous allocation ID
+         */
+        newInitializingAllocationIds.add(AllocationId.newInitializing());
+        tracker.updateFromClusterManager(
+            initialClusterStateVersion + 2,
+            ids(newActiveAllocationIds),
+            routingTable(newInitializingAllocationIds, primaryId)
+        );
+        assertTrue(newActiveAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(
+            newActiveAllocationIds.stream()
+                .filter(a -> a.equals(primaryId) == false)
+                .allMatch(
+                    a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).getLocalCheckpoint() == SequenceNumbers.UNASSIGNED_SEQ_NO
+                )
+        );
+        assertTrue(newInitializingAllocationIds.stream().noneMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+        assertTrue(
+            newInitializingAllocationIds.stream()
+                .allMatch(
+                    a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).getLocalCheckpoint() == SequenceNumbers.UNASSIGNED_SEQ_NO
+                )
+        );
+
+        // the tracking allocation IDs should play no role in determining the global checkpoint
+        final Map<AllocationId, Integer> activeLocalCheckpoints = newActiveAllocationIds.stream()
+            .collect(Collectors.toMap(Function.identity(), a -> randomIntBetween(1, 1024)));
+        activeLocalCheckpoints.forEach((a, l) -> updateLocalCheckpoint(tracker, a.getId(), l));
+        final Map<AllocationId, Integer> initializingLocalCheckpoints = newInitializingAllocationIds.stream()
+            .collect(Collectors.toMap(Function.identity(), a -> randomIntBetween(1, 1024)));
+        initializingLocalCheckpoints.forEach((a, l) -> updateLocalCheckpoint(tracker, a.getId(), l));
+        assertTrue(
+            activeLocalCheckpoints.entrySet()
+                .stream()
+                .allMatch(e -> tracker.getTrackedLocalCheckpointForShard(e.getKey().getId()).getLocalCheckpoint() == e.getValue())
+        );
+        assertTrue(
+            initializingLocalCheckpoints.entrySet()
+                .stream()
+                .allMatch(e -> tracker.getTrackedLocalCheckpointForShard(e.getKey().getId()).getLocalCheckpoint() == e.getValue())
+        );
+        final long primaryLocalCheckpoint = activeLocalCheckpoints.get(primaryId);
+        assertThat(tracker.getGlobalCheckpoint(), equalTo(primaryLocalCheckpoint));
+        assertThat(updatedGlobalCheckpoint.get(), equalTo(primaryLocalCheckpoint));
+        final long minimumInitailizingLocalCheckpoint = (long) initializingLocalCheckpoints.values().stream().min(Integer::compareTo).get();
+
+        // now we are going to add a new allocation ID and bring it in sync which should move it to the in-sync allocation IDs
+        final long localCheckpoint = randomIntBetween(
+            0,
+            Math.toIntExact(Math.min(primaryLocalCheckpoint, minimumInitailizingLocalCheckpoint) - 1)
+        );
+
+        // using a different length than we have been using above ensures that we can not collide with a previous allocation ID
+        final AllocationId newSyncingAllocationId = AllocationId.newInitializing();
+        newInitializingAllocationIds.add(newSyncingAllocationId);
+        tracker.updateFromClusterManager(
+            initialClusterStateVersion + 3,
+            ids(newActiveAllocationIds),
+            routingTable(newInitializingAllocationIds, primaryId)
+        );
+        addPeerRecoveryRetentionLease(tracker, newSyncingAllocationId);
+        final CyclicBarrier barrier = new CyclicBarrier(2);
+        final Thread thread = new Thread(() -> {
+            try {
+                barrier.await();
+                tracker.initiateTracking(newSyncingAllocationId.getId());
+                tracker.markAllocationIdAsInSync(newSyncingAllocationId.getId(), localCheckpoint);
+                barrier.await();
+            } catch (final BrokenBarrierException | InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        thread.start();
+
+        barrier.await();
+
+        assertBusy(() -> {
+            assertFalse(tracker.pendingInSync.contains(newSyncingAllocationId.getId()));
+            assertTrue(tracker.getTrackedLocalCheckpointForShard(newSyncingAllocationId.getId()).inSync);
+        });
+
+        tracker.updateLocalCheckpoint(newSyncingAllocationId.getId(), randomIntBetween(Math.toIntExact(primaryLocalCheckpoint), 1024));
+
+        barrier.await();
+
+        assertFalse(tracker.pendingInSync.contains(newSyncingAllocationId.getId()));
+        assertTrue(tracker.getTrackedLocalCheckpointForShard(newSyncingAllocationId.getId()).inSync);
+
+        /*
+         * The new in-sync allocation ID is in the in-sync set now yet the cluster-manager does not know this; the allocation ID should still be in
+         * the in-sync set even if we receive a cluster state update that does not reflect this.
+         *
+         */
+        tracker.updateFromClusterManager(
+            initialClusterStateVersion + 4,
+            ids(newActiveAllocationIds),
+            routingTable(newInitializingAllocationIds, primaryId)
+        );
+        assertTrue(tracker.getTrackedLocalCheckpointForShard(newSyncingAllocationId.getId()).inSync);
+        assertFalse(tracker.pendingInSync.contains(newSyncingAllocationId.getId()));
+    }
+
+    public void testSegmentReplicationCheckpointTracking() {
+        Settings settings = Settings.builder().put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        final int numberOfActiveAllocationsIds = randomIntBetween(2, 16);
+        final int numberOfInitializingIds = randomIntBetween(2, 16);
+        final Tuple<Set<AllocationId>, Set<AllocationId>> activeAndInitializingAllocationIds = randomActiveAndInitializingAllocationIds(
+            numberOfActiveAllocationsIds,
+            numberOfInitializingIds
+        );
+        final Set<AllocationId> activeAllocationIds = activeAndInitializingAllocationIds.v1();
+        final Set<AllocationId> initializingIds = activeAndInitializingAllocationIds.v2();
+        AllocationId primaryId = activeAllocationIds.iterator().next();
+        IndexShardRoutingTable routingTable = routingTable(initializingIds, primaryId);
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+        assertThat(tracker.getReplicationGroup().getInSyncAllocationIds(), equalTo(ids(activeAllocationIds)));
+        assertThat(tracker.getReplicationGroup().getRoutingTable(), equalTo(routingTable));
+        assertTrue(activeAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+
+        initializingIds.forEach(aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED));
+
+        final StoreFileMetadata segment_1 = new StoreFileMetadata("segment_1", 1L, "abcd", Version.LATEST);
+        final StoreFileMetadata segment_2 = new StoreFileMetadata("segment_2", 50L, "abcd", Version.LATEST);
+        final StoreFileMetadata segment_3 = new StoreFileMetadata("segment_3", 100L, "abcd", Version.LATEST);
+        final ReplicationCheckpoint initialCheckpoint = new ReplicationCheckpoint(
+            tracker.shardId(),
+            0L,
+            1,
+            1,
+            1L,
+            Codec.getDefault().getName(),
+            Map.of("segment_1", segment_1)
+        );
+        final ReplicationCheckpoint secondCheckpoint = new ReplicationCheckpoint(
+            tracker.shardId(),
+            0L,
+            2,
+            2,
+            51L,
+            Codec.getDefault().getName(),
+            Map.of("segment_1", segment_1, "segment_2", segment_2)
+        );
+        final ReplicationCheckpoint thirdCheckpoint = new ReplicationCheckpoint(
+            tracker.shardId(),
+            0L,
+            2,
+            3,
+            151L,
+            Codec.getDefault().getName(),
+            Map.of("segment_1", segment_1, "segment_2", segment_2, "segment_3", segment_3)
+        );
+
+        tracker.setLatestReplicationCheckpoint(initialCheckpoint);
+        tracker.startReplicationLagTimers(initialCheckpoint);
+        tracker.setLatestReplicationCheckpoint(secondCheckpoint);
+        tracker.startReplicationLagTimers(secondCheckpoint);
+        tracker.setLatestReplicationCheckpoint(thirdCheckpoint);
+        tracker.startReplicationLagTimers(thirdCheckpoint);
+
+        final Set<String> expectedIds = ids(initializingIds);
+
+        Set<SegmentReplicationShardStats> groupStats = tracker.getSegmentReplicationStats();
+        assertEquals(expectedIds.size(), groupStats.size());
+        for (SegmentReplicationShardStats shardStat : groupStats) {
+            assertEquals(3, shardStat.getCheckpointsBehindCount());
+            assertEquals(151L, shardStat.getBytesBehindCount());
+            assertTrue(shardStat.getCurrentReplicationLagMillis() >= shardStat.getCurrentReplicationTimeMillis());
+        }
+
+        // simulate replicas moved up to date.
+        final Map<String, ReplicationTracker.CheckpointState> checkpoints = tracker.checkpoints;
+        for (String id : expectedIds) {
+            final ReplicationTracker.CheckpointState checkpointState = checkpoints.get(id);
+            assertEquals(3, checkpointState.checkpointTimers.size());
+            tracker.updateVisibleCheckpointForShard(id, initialCheckpoint);
+            assertEquals(2, checkpointState.checkpointTimers.size());
+        }
+
+        groupStats = tracker.getSegmentReplicationStats();
+        assertEquals(expectedIds.size(), groupStats.size());
+        for (SegmentReplicationShardStats shardStat : groupStats) {
+            assertEquals(2, shardStat.getCheckpointsBehindCount());
+            assertEquals(150L, shardStat.getBytesBehindCount());
+        }
+
+        for (String id : expectedIds) {
+            final ReplicationTracker.CheckpointState checkpointState = checkpoints.get(id);
+            assertEquals(2, checkpointState.checkpointTimers.size());
+            tracker.updateVisibleCheckpointForShard(id, thirdCheckpoint);
+            assertEquals(0, checkpointState.checkpointTimers.size());
+        }
+
+        groupStats = tracker.getSegmentReplicationStats();
+        assertEquals(expectedIds.size(), groupStats.size());
+        for (SegmentReplicationShardStats shardStat : groupStats) {
+            assertEquals(0, shardStat.getCheckpointsBehindCount());
+            assertEquals(0L, shardStat.getBytesBehindCount());
+        }
+    }
+
+    public void testSegmentReplicationCheckpointTrackingInvalidAllocationIDs() {
+        Settings settings = Settings.builder().put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        final long initialClusterStateVersion = randomNonNegativeLong();
+        final int numberOfActiveAllocationsIds = randomIntBetween(2, 16);
+        final int numberOfInitializingIds = randomIntBetween(2, 16);
+        final Tuple<Set<AllocationId>, Set<AllocationId>> activeAndInitializingAllocationIds = randomActiveAndInitializingAllocationIds(
+            numberOfActiveAllocationsIds,
+            numberOfInitializingIds
+        );
+        final Set<AllocationId> activeAllocationIds = activeAndInitializingAllocationIds.v1();
+        final Set<AllocationId> initializingIds = activeAndInitializingAllocationIds.v2();
+        AllocationId primaryId = activeAllocationIds.iterator().next();
+        IndexShardRoutingTable routingTable = routingTable(initializingIds, primaryId);
+        final ReplicationTracker tracker = newTracker(primaryId, settings);
+        tracker.updateFromClusterManager(initialClusterStateVersion, ids(activeAllocationIds), routingTable);
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+
+        initializingIds.forEach(aId -> markAsTrackingAndInSyncQuietly(tracker, aId.getId(), NO_OPS_PERFORMED));
+
+        assertEquals(tracker.getReplicationGroup().getRoutingTable(), routingTable);
+        assertEquals(
+            "All active & initializing ids are now marked in-sync",
+            Sets.union(ids(activeAllocationIds), ids(initializingIds)),
+            tracker.getReplicationGroup().getInSyncAllocationIds()
+        );
+
+        assertEquals(
+            "Active ids are in-sync but still unavailable",
+            tracker.getReplicationGroup().getUnavailableInSyncShards(),
+            Sets.difference(ids(activeAllocationIds), Set.of(primaryId.getId()))
+        );
+        assertTrue(activeAllocationIds.stream().allMatch(a -> tracker.getTrackedLocalCheckpointForShard(a.getId()).inSync));
+
+        final ReplicationCheckpoint initialCheckpoint = new ReplicationCheckpoint(
+            tracker.shardId(),
+            0L,
+            1,
+            1,
+            1L,
+            Codec.getDefault().getName(),
+            Collections.emptyMap()
+        );
+        tracker.setLatestReplicationCheckpoint(initialCheckpoint);
+        tracker.startReplicationLagTimers(initialCheckpoint);
+
+        // we expect that the only returned ids from getSegmentReplicationStats will be the initializing ids we marked with
+        // markAsTrackingAndInSyncQuietly.
+        // This is because the ids marked active initially are still unavailable (don't have an associated routing entry).
+        final Set<String> expectedIds = ids(initializingIds);
+        Set<SegmentReplicationShardStats> groupStats = tracker.getSegmentReplicationStats();
+        final Set<String> actualIds = groupStats.stream().map(SegmentReplicationShardStats::getAllocationId).collect(Collectors.toSet());
+        assertEquals(expectedIds, actualIds);
+        for (SegmentReplicationShardStats shardStat : groupStats) {
+            assertEquals(1, shardStat.getCheckpointsBehindCount());
+        }
+
+        // simulate replicas moved up to date.
+        final Map<String, ReplicationTracker.CheckpointState> checkpoints = tracker.checkpoints;
+        for (String id : expectedIds) {
+            final ReplicationTracker.CheckpointState checkpointState = checkpoints.get(id);
+            assertEquals(1, checkpointState.checkpointTimers.size());
+            tracker.updateVisibleCheckpointForShard(id, initialCheckpoint);
+            assertEquals(0, checkpointState.checkpointTimers.size());
+        }
+
+        // Unknown allocation ID will be ignored.
+        tracker.updateVisibleCheckpointForShard("randomAllocationID", initialCheckpoint);
+        assertThrows(AssertionError.class, () -> tracker.updateVisibleCheckpointForShard(tracker.shardAllocationId, initialCheckpoint));
+    }
+
+    public void testPrimaryContextHandoffWithRemoteTranslogEnabled() throws IOException {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", settings);
+        final ShardId shardId = new ShardId("test", "_na_", 0);
+
+        FakeClusterState clusterState = initialState();
+        final AllocationId aId = clusterState.routingTable.primaryShard().allocationId();
+        final LongConsumer onUpdate = updatedGlobalCheckpoint -> {};
+        final long primaryTerm = randomNonNegativeLong();
+        final long globalCheckpoint = UNASSIGNED_SEQ_NO;
+        final BiConsumer<RetentionLeases, ActionListener<ReplicationResponse>> onNewRetentionLease = (leases, listener) -> {};
+        ReplicationTracker oldPrimary = new ReplicationTracker(
+            shardId,
+            aId.getId(),
+            indexSettings,
+            primaryTerm,
+            globalCheckpoint,
+            onUpdate,
+            () -> 0L,
+            onNewRetentionLease,
+            OPS_BASED_RECOVERY_ALWAYS_REASONABLE
+        );
+        ReplicationTracker newPrimary = new ReplicationTracker(
+            shardId,
+            aId.getRelocationId(),
+            indexSettings,
+            primaryTerm,
+            globalCheckpoint,
+            onUpdate,
+            () -> 0L,
+            onNewRetentionLease,
+            OPS_BASED_RECOVERY_ALWAYS_REASONABLE
+        );
+
+        Set<String> allocationIds = new HashSet<>(Arrays.asList(oldPrimary.shardAllocationId, newPrimary.shardAllocationId));
+
+        clusterState.apply(oldPrimary);
+        clusterState.apply(newPrimary);
+
+        oldPrimary.activatePrimaryMode(randomIntBetween(Math.toIntExact(NO_OPS_PERFORMED), 10));
+        addPeerRecoveryRetentionLease(oldPrimary, newPrimary.shardAllocationId);
+        newPrimary.updateRetentionLeasesOnReplica(oldPrimary.getRetentionLeases());
+
+        final int numUpdates = randomInt(10);
+        for (int i = 0; i < numUpdates; i++) {
+            if (rarely()) {
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(oldPrimary);
+                clusterState.apply(newPrimary);
+            }
+            if (randomBoolean()) {
+                randomLocalCheckpointUpdate(oldPrimary);
+            }
+            if (randomBoolean()) {
+                randomMarkInSync(oldPrimary, newPrimary);
+            }
+        }
+
+        // simulate transferring the global checkpoint to the new primary after finalizing recovery before the handoff
+        markAsTrackingAndInSyncQuietly(
+            oldPrimary,
+            newPrimary.shardAllocationId,
+            Math.max(SequenceNumbers.NO_OPS_PERFORMED, oldPrimary.getGlobalCheckpoint() + randomInt(5))
+        );
+        oldPrimary.updateGlobalCheckpointForShard(newPrimary.shardAllocationId, oldPrimary.getGlobalCheckpoint());
+        ReplicationTracker.PrimaryContext primaryContext = oldPrimary.startRelocationHandoff(newPrimary.shardAllocationId);
+
+        if (randomBoolean()) {
+            // cluster state update after primary context handoff
+            if (randomBoolean()) {
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(oldPrimary);
+                clusterState.apply(newPrimary);
+            }
+
+            // abort handoff, check that we can continue updates and retry handoff
+            oldPrimary.abortRelocationHandoff();
+
+            if (rarely()) {
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(oldPrimary);
+                clusterState.apply(newPrimary);
+            }
+            if (randomBoolean()) {
+                randomLocalCheckpointUpdate(oldPrimary);
+            }
+            if (randomBoolean()) {
+                randomMarkInSync(oldPrimary, newPrimary);
+            }
+
+            // do another handoff
+            primaryContext = oldPrimary.startRelocationHandoff(newPrimary.shardAllocationId);
+        }
+
+        // send primary context through the wire
+        BytesStreamOutput output = new BytesStreamOutput();
+        primaryContext.writeTo(output);
+        StreamInput streamInput = output.bytes().streamInput();
+        primaryContext = new ReplicationTracker.PrimaryContext(streamInput);
+        switch (randomInt(3)) {
+            case 0: {
+                // apply cluster state update on old primary while primary context is being transferred
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(oldPrimary);
+                // activate new primary
+                newPrimary.activateWithPrimaryContext(primaryContext);
+                // apply cluster state update on new primary so that the states on old and new primary are comparable
+                clusterState.apply(newPrimary);
+                break;
+            }
+            case 1: {
+                // apply cluster state update on new primary while primary context is being transferred
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(newPrimary);
+                // activate new primary
+                newPrimary.activateWithPrimaryContext(primaryContext);
+                // apply cluster state update on old primary so that the states on old and new primary are comparable
+                clusterState.apply(oldPrimary);
+                break;
+            }
+            case 2: {
+                // apply cluster state update on both copies while primary context is being transferred
+                clusterState = randomUpdateClusterState(allocationIds, clusterState);
+                clusterState.apply(oldPrimary);
+                clusterState.apply(newPrimary);
+                newPrimary.activateWithPrimaryContext(primaryContext);
+                break;
+            }
+            case 3: {
+                // no cluster state update
+                newPrimary.activateWithPrimaryContext(primaryContext);
+                break;
+            }
+        }
+
+        assertTrue(oldPrimary.primaryMode);
+        assertTrue(newPrimary.primaryMode);
+        assertThat(newPrimary.appliedClusterStateVersion, equalTo(oldPrimary.appliedClusterStateVersion));
+        /*
+         * We can not assert on shared knowledge of the global checkpoint between the old primary and the new primary as the new primary
+         * will update its global checkpoint state without the old primary learning of it, and the old primary could have updated its
+         * global checkpoint state after the primary context was transferred.
+         */
+        Map<String, ReplicationTracker.CheckpointState> oldPrimaryCheckpointsCopy = new HashMap<>(oldPrimary.checkpoints);
+        oldPrimaryCheckpointsCopy.remove(oldPrimary.shardAllocationId);
+        oldPrimaryCheckpointsCopy.remove(newPrimary.shardAllocationId);
+        Map<String, ReplicationTracker.CheckpointState> newPrimaryCheckpointsCopy = new HashMap<>(newPrimary.checkpoints);
+        newPrimaryCheckpointsCopy.remove(oldPrimary.shardAllocationId);
+        newPrimaryCheckpointsCopy.remove(newPrimary.shardAllocationId);
+        assertThat(newPrimaryCheckpointsCopy, equalTo(oldPrimaryCheckpointsCopy));
+        // we can however assert that shared knowledge of the local checkpoint and in-sync status is equal
+        assertThat(
+            oldPrimary.checkpoints.get(oldPrimary.shardAllocationId).localCheckpoint,
+            equalTo(newPrimary.checkpoints.get(oldPrimary.shardAllocationId).localCheckpoint)
+        );
+        assertThat(
+            oldPrimary.checkpoints.get(newPrimary.shardAllocationId).localCheckpoint,
+            equalTo(newPrimary.checkpoints.get(newPrimary.shardAllocationId).localCheckpoint)
+        );
+        assertThat(
+            oldPrimary.checkpoints.get(oldPrimary.shardAllocationId).inSync,
+            equalTo(newPrimary.checkpoints.get(oldPrimary.shardAllocationId).inSync)
+        );
+        assertThat(
+            oldPrimary.checkpoints.get(newPrimary.shardAllocationId).inSync,
+            equalTo(newPrimary.checkpoints.get(newPrimary.shardAllocationId).inSync)
+        );
+        assertThat(newPrimary.getGlobalCheckpoint(), equalTo(oldPrimary.getGlobalCheckpoint()));
+        assertThat(newPrimary.routingTable, equalTo(oldPrimary.routingTable));
+        assertThat(newPrimary.replicationGroup, equalTo(oldPrimary.replicationGroup));
+
+        assertFalse(oldPrimary.relocated);
+        oldPrimary.completeRelocationHandoff();
+        assertFalse(oldPrimary.primaryMode);
+        assertTrue(oldPrimary.relocated);
+    }
+
+    public void testIllegalStateExceptionIfUnknownAllocationIdWithRemoteTranslogEnabled() {
+        final AllocationId active = AllocationId.newInitializing();
+        final AllocationId initializing = AllocationId.newInitializing();
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .build();
+        final ReplicationTracker tracker = newTracker(active, settings);
+        tracker.updateFromClusterManager(
+            randomNonNegativeLong(),
+            Collections.singleton(active.getId()),
+            routingTable(Collections.singleton(initializing), active)
+        );
+        tracker.activatePrimaryMode(NO_OPS_PERFORMED);
+
+        expectThrows(IllegalStateException.class, () -> tracker.initiateTracking(randomAlphaOfLength(10)));
+        expectThrows(IllegalStateException.class, () -> tracker.markAllocationIdAsInSync(randomAlphaOfLength(10), randomNonNegativeLong()));
+    }
+
+    public void testSegRepTimer() throws Throwable {
+        SegmentReplicationLagTimer timer = new SegmentReplicationLagTimer();
+        Thread.sleep(100);
+        timer.start();
+        Thread.sleep(100);
+        timer.stop();
+        assertTrue("Total time since timer started should be greater than 100", timer.time() >= 100);
+        assertTrue("Total time since timer was created should be greater than 200", timer.totalElapsedTime() >= 200);
+        assertTrue("Total elapsed time should be greater than time since timer start", timer.totalElapsedTime() - timer.time() >= 100);
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseActionsTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseActionsTests.java
index 1a52fd2de39e0..861ef5194fc27 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseActionsTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseActionsTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.stats.IndicesStatsAction;
 import org.opensearch.action.admin.indices.stats.IndicesStatsRequest;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.node.Node;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncActionTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncActionTests.java
index 54a88d57b2b69..ed04d9a20f18e 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncActionTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseBackgroundSyncActionTests.java
@@ -32,22 +32,24 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.replication.ReplicationMode;
 import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.gateway.WriteStateException;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -84,7 +86,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -209,4 +212,30 @@ public void testBlocks() {
         assertNull(action.indexBlockLevel());
     }
 
+    public void testGetReplicationModeWithRemoteTranslog() {
+        final RetentionLeaseBackgroundSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        final RetentionLeaseBackgroundSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private RetentionLeaseBackgroundSyncAction createAction() {
+        return new RetentionLeaseBackgroundSyncAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            mock(IndicesService.class),
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet())
+        );
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsTests.java
index 10b1673710fba..f5fca93436962 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsWireSerializingTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsWireSerializingTests.java
index 83e2c5f3e3f42..c5e79abf53419 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsWireSerializingTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseStatsWireSerializingTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseSyncActionTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseSyncActionTests.java
index 60ee3360ff235..d9bca55a208c2 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseSyncActionTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseSyncActionTests.java
@@ -32,22 +32,24 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.ActionTestUtils;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.replication.ReplicationMode;
 import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexingPressureService;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.CapturingTransport;
 import org.opensearch.threadpool.TestThreadPool;
@@ -83,7 +85,8 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> clusterService.localNode(),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -206,4 +209,32 @@ public void testBlocks() {
         assertNull(action.indexBlockLevel());
     }
 
+    public void testGetReplicationModeWithRemoteTranslog() {
+        final RetentionLeaseSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        final RetentionLeaseSyncAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.NO_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private RetentionLeaseSyncAction createAction() {
+        return new RetentionLeaseSyncAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            mock(IndicesService.class),
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet()),
+            new IndexingPressureService(Settings.EMPTY, clusterService),
+            new SystemIndices(emptyMap())
+        );
+    }
+
 }
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseTests.java
index e5e5a185050e1..2c7714f425956 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.seqno;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseXContentTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseXContentTests.java
index bc20f54f5f9ad..e67f27831c3cd 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseXContentTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeaseXContentTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesTests.java
index 9dbe7a5ad1282..a279ab7cdc8db 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesXContentTests.java b/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesXContentTests.java
index 2aafd4fbd6bda..9279bea8f0230 100644
--- a/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesXContentTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/RetentionLeasesXContentTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/seqno/SequenceNumbersTests.java b/server/src/test/java/org/opensearch/index/seqno/SequenceNumbersTests.java
index e5a0ab4158cfd..8abdb3c540a6f 100644
--- a/server/src/test/java/org/opensearch/index/seqno/SequenceNumbersTests.java
+++ b/server/src/test/java/org/opensearch/index/seqno/SequenceNumbersTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.index.seqno;
 
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/shard/CloseableRetryableRefreshListenerTests.java b/server/src/test/java/org/opensearch/index/shard/CloseableRetryableRefreshListenerTests.java
new file mode 100644
index 0000000000000..01242063caa77
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/CloseableRetryableRefreshListenerTests.java
@@ -0,0 +1,461 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class CloseableRetryableRefreshListenerTests extends OpenSearchTestCase {
+
+    private static final Logger logger = LogManager.getLogger(CloseableRetryableRefreshListenerTests.class);
+
+    private ThreadPool threadPool;
+
+    @Before
+    public void init() {
+        threadPool = new TestThreadPool(getTestName());
+    }
+
+    /**
+     * This tests that the performAfterRefresh method is being invoked when the afterRefresh method is invoked. We check that the countDownLatch is decreasing as intended to validate that the performAfterRefresh is being invoked.
+     */
+    public void testPerformAfterRefresh() throws IOException {
+
+        CountDownLatch countDownLatch = new CountDownLatch(2);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(mock(ThreadPool.class)) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return false;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+
+        // First invocation of afterRefresh method
+        testRefreshListener.afterRefresh(true);
+        assertEquals(1, countDownLatch.getCount());
+
+        // Second invocation of afterRefresh method
+        testRefreshListener.afterRefresh(true);
+        assertEquals(0, countDownLatch.getCount());
+        testRefreshListener.close();
+    }
+
+    /**
+     * This tests that close is acquiring all permits and even if the afterRefresh method is called, it is no-op.
+     */
+    public void testCloseAfterRefresh() throws IOException {
+        final int initialCount = randomIntBetween(10, 100);
+        final CountDownLatch countDownLatch = new CountDownLatch(initialCount);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(mock(ThreadPool.class)) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return false;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+
+        int refreshCount = randomIntBetween(1, initialCount);
+        for (int i = 0; i < refreshCount; i++) {
+            testRefreshListener.afterRefresh(true);
+        }
+        assertEquals(initialCount - refreshCount, countDownLatch.getCount());
+
+        // Closing the refresh listener so that no further afterRefreshes are executed going forward
+        testRefreshListener.close();
+
+        for (int i = 0; i < initialCount - refreshCount; i++) {
+            testRefreshListener.afterRefresh(true);
+        }
+        assertEquals(initialCount - refreshCount, countDownLatch.getCount());
+    }
+
+    /**
+     * This tests that the retry does not get triggered when there are missing configurations or method overrides that empowers the retry to happen.
+     */
+    public void testNoRetry() throws IOException {
+        int initialCount = randomIntBetween(10, 100);
+        final CountDownLatch countDownLatch = new CountDownLatch(initialCount);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(mock(ThreadPool.class)) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        assertEquals(initialCount - 1, countDownLatch.getCount());
+        testRefreshListener.close();
+
+        testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        assertEquals(initialCount - 2, countDownLatch.getCount());
+        testRefreshListener.close();
+
+        testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        assertEquals(initialCount - 3, countDownLatch.getCount());
+        testRefreshListener.close();
+
+        testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                return TimeValue.timeValueMillis(100);
+            }
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        assertEquals(initialCount - 4, countDownLatch.getCount());
+        testRefreshListener.close();
+    }
+
+    /**
+     * This tests that retry gets scheduled and executed when the configurations and method overrides are done properly.
+     */
+    public void testRetry() throws Exception {
+        int initialCount = randomIntBetween(10, 20);
+        final CountDownLatch countDownLatch = new CountDownLatch(initialCount);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                return TimeValue.timeValueMillis(100);
+            }
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+
+            @Override
+            protected boolean isRetryEnabled() {
+                return true;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        assertBusy(() -> assertEquals(0, countDownLatch.getCount()));
+        testRefreshListener.close();
+    }
+
+    /**
+     * This tests that once close method is invoked, then even the retries would become no-op.
+     */
+    public void testCloseWithRetryPending() throws IOException {
+        int initialCount = randomIntBetween(10, 20);
+        final CountDownLatch countDownLatch = new CountDownLatch(initialCount);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                countDownLatch.countDown();
+                return countDownLatch.getCount() == 0;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                return TimeValue.timeValueMillis(100);
+            }
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        testRefreshListener.afterRefresh(randomBoolean());
+        testRefreshListener.close();
+        assertNotEquals(0, countDownLatch.getCount());
+    }
+
+    public void testCloseWaitsForAcquiringAllPermits() throws Exception {
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                try {
+                    Thread.sleep(5000);
+                } catch (InterruptedException e) {
+                    throw new AssertionError(e);
+                }
+                countDownLatch.countDown();
+                return false;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+        };
+        Thread thread = new Thread(() -> {
+            try {
+                testRefreshListener.afterRefresh(randomBoolean());
+            } catch (IOException e) {
+                throw new AssertionError(e);
+            }
+        });
+        thread.start();
+        assertBusy(() -> assertEquals(0, countDownLatch.getCount()));
+        testRefreshListener.close();
+    }
+
+    public void testScheduleRetryAfterClose() throws Exception {
+        // This tests that once the listener has been closed, even the retries would not be scheduled.
+        final AtomicLong runCount = new AtomicLong();
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    throw new AssertionError(e);
+                }
+                runCount.incrementAndGet();
+                return false;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    throw new AssertionError(e);
+                }
+                return TimeValue.timeValueMillis(100);
+            }
+        };
+        Thread thread1 = new Thread(() -> {
+            try {
+                testRefreshListener.afterRefresh(true);
+            } catch (IOException e) {
+                throw new AssertionError(e);
+            }
+        });
+        Thread thread2 = new Thread(() -> {
+            try {
+                Thread.sleep(500);
+                testRefreshListener.close();
+            } catch (IOException | InterruptedException e) {
+                throw new AssertionError(e);
+            }
+        });
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        assertBusy(() -> assertEquals(1, runCount.get()));
+    }
+
+    public void testConcurrentScheduleRetry() throws Exception {
+        // This tests that there can be only 1 retry that can be scheduled at a time.
+        final AtomicLong runCount = new AtomicLong();
+        final AtomicInteger retryCount = new AtomicInteger(0);
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(threadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                retryCount.incrementAndGet();
+                runCount.incrementAndGet();
+                return retryCount.get() >= 2;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                return TimeValue.timeValueMillis(5000);
+            }
+
+            @Override
+            protected boolean isRetryEnabled() {
+                return true;
+            }
+        };
+        testRefreshListener.afterRefresh(true);
+        testRefreshListener.afterRefresh(true);
+        assertBusy(() -> assertEquals(3, runCount.get()));
+        testRefreshListener.close();
+    }
+
+    public void testExceptionDuringThreadPoolSchedule() throws Exception {
+        // This tests that if there are exceptions while scheduling the task in the threadpool, the retrySchedule boolean
+        // is reset properly to allow future scheduling to happen.
+        AtomicInteger runCount = new AtomicInteger();
+        ThreadPool mockThreadPool = mock(ThreadPool.class);
+        when(mockThreadPool.schedule(any(), any(), any())).thenThrow(new RuntimeException());
+        CloseableRetryableRefreshListener testRefreshListener = new CloseableRetryableRefreshListener(mockThreadPool) {
+            @Override
+            protected boolean performAfterRefreshWithPermit(boolean didRefresh) {
+                runCount.incrementAndGet();
+                return false;
+            }
+
+            @Override
+            public void beforeRefresh() {}
+
+            @Override
+            protected Logger getLogger() {
+                return logger;
+            }
+
+            @Override
+            protected String getRetryThreadPoolName() {
+                return ThreadPool.Names.REMOTE_REFRESH_RETRY;
+            }
+
+            @Override
+            protected TimeValue getNextRetryInterval() {
+                return TimeValue.timeValueMillis(100);
+            }
+
+            @Override
+            protected boolean isRetryEnabled() {
+                return true;
+            }
+        };
+        assertThrows(RuntimeException.class, () -> testRefreshListener.afterRefresh(true));
+        assertBusy(() -> assertFalse(testRefreshListener.getRetryScheduledStatus()));
+        assertEquals(1, runCount.get());
+        testRefreshListener.close();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        terminate(threadPool);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/DocsStatsTests.java b/server/src/test/java/org/opensearch/index/shard/DocsStatsTests.java
index 8d6d4a6502771..c534f8e0a00be 100644
--- a/server/src/test/java/org/opensearch/index/shard/DocsStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/DocsStatsTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/index/shard/GlobalCheckpointListenersTests.java b/server/src/test/java/org/opensearch/index/shard/GlobalCheckpointListenersTests.java
index 28e29ec0d0249..db575d7d90bbf 100644
--- a/server/src/test/java/org/opensearch/index/shard/GlobalCheckpointListenersTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/GlobalCheckpointListenersTests.java
@@ -34,15 +34,15 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.Assertions;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.index.Index;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.Scheduler;
 import org.junit.After;
-import org.mockito.ArgumentCaptor;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -64,6 +64,8 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.mockito.ArgumentCaptor;
+
 import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
 import static org.hamcrest.Matchers.containsString;
@@ -625,11 +627,9 @@ public void testFailingListenerAfterTimeout() throws InterruptedException {
         }).when(mockLogger).warn(any(String.class), any(RuntimeException.class));
         final GlobalCheckpointListeners globalCheckpointListeners = new GlobalCheckpointListeners(shardId, scheduler, mockLogger);
         final TimeValue timeout = TimeValue.timeValueMillis(randomIntBetween(1, 50));
-        globalCheckpointListeners.add(
-            NO_OPS_PERFORMED,
-            maybeMultipleInvocationProtectingListener((g, e) -> { throw new RuntimeException("failure"); }),
-            timeout
-        );
+        globalCheckpointListeners.add(NO_OPS_PERFORMED, maybeMultipleInvocationProtectingListener((g, e) -> {
+            throw new RuntimeException("failure");
+        }), timeout);
         latch.await();
         final ArgumentCaptor<String> message = ArgumentCaptor.forClass(String.class);
         final ArgumentCaptor<RuntimeException> t = ArgumentCaptor.forClass(RuntimeException.class);
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexReaderWrapperTests.java b/server/src/test/java/org/opensearch/index/shard/IndexReaderWrapperTests.java
index 6b58633d5cd2e..4134f1bd91985 100644
--- a/server/src/test/java/org/opensearch/index/shard/IndexReaderWrapperTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/IndexReaderWrapperTests.java
@@ -36,7 +36,6 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.tests.index.FieldFilterLeafReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
@@ -46,9 +45,11 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.FieldFilterLeafReader;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexShardOperationPermitsTests.java b/server/src/test/java/org/opensearch/index/shard/IndexShardOperationPermitsTests.java
index 9d73fa3524a8c..0097a615f5e91 100644
--- a/server/src/test/java/org/opensearch/index/shard/IndexShardOperationPermitsTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/IndexShardOperationPermitsTests.java
@@ -31,14 +31,15 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -226,18 +227,12 @@ public void testOperationsIfClosed() {
 
     public void testBlockIfClosed() {
         permits.close();
-        expectThrows(
-            IndexShardClosedException.class,
-            () -> permits.blockOperations(randomInt(10), TimeUnit.MINUTES, () -> { throw new IllegalArgumentException("fake error"); })
-        );
-        expectThrows(
-            IndexShardClosedException.class,
-            () -> permits.asyncBlockOperations(
-                wrap(() -> { throw new IllegalArgumentException("fake error"); }),
-                randomInt(10),
-                TimeUnit.MINUTES
-            )
-        );
+        expectThrows(IndexShardClosedException.class, () -> permits.blockOperations(randomInt(10), TimeUnit.MINUTES, () -> {
+            throw new IllegalArgumentException("fake error");
+        }));
+        expectThrows(IndexShardClosedException.class, () -> permits.asyncBlockOperations(wrap(() -> {
+            throw new IllegalArgumentException("fake error");
+        }), randomInt(10), TimeUnit.MINUTES));
     }
 
     public void testOperationsDelayedIfBlock() throws ExecutionException, InterruptedException, TimeoutException {
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexShardRetentionLeaseTests.java b/server/src/test/java/org/opensearch/index/shard/IndexShardRetentionLeaseTests.java
index 3de5175bac7c5..e6297c0f239e9 100644
--- a/server/src/test/java/org/opensearch/index/shard/IndexShardRetentionLeaseTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/IndexShardRetentionLeaseTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.shard;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.ShardRoutingHelper;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.InternalEngineFactory;
 import org.opensearch.index.seqno.ReplicationTracker;
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexShardTests.java b/server/src/test/java/org/opensearch/index/shard/IndexShardTests.java
index 3bc5218e2f61f..083526ba77e2b 100644
--- a/server/src/test/java/org/opensearch/index/shard/IndexShardTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/IndexShardTests.java
@@ -36,20 +36,21 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.ReferenceManager;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.FilterDirectory;
 import org.apache.lucene.store.IOContext;
+import org.apache.lucene.tests.mockfile.ExtrasFS;
+import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Constants;
-import org.junit.Assert;
-import org.opensearch.Assertions;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequest;
 import org.opensearch.action.admin.indices.stats.CommonStats;
@@ -70,13 +71,11 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.IndexScopedSettings;
@@ -85,10 +84,16 @@
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.AtomicArray;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.codec.CodecService;
@@ -100,6 +105,8 @@
 import org.opensearch.index.engine.EngineTestCase;
 import org.opensearch.index.engine.InternalEngine;
 import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngine;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
 import org.opensearch.index.engine.ReadOnlyEngine;
 import org.opensearch.index.fielddata.FieldDataStats;
 import org.opensearch.index.fielddata.IndexFieldData;
@@ -116,23 +123,33 @@
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.mapper.VersionFieldMapper;
+import org.opensearch.index.remote.RemoteSegmentStats;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLease;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.seqno.SeqNoStats;
 import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreStats;
 import org.opensearch.index.store.StoreUtils;
+import org.opensearch.index.translog.InternalTranslogFactory;
+import org.opensearch.index.translog.RemoteBlobStoreInternalTranslogFactory;
+import org.opensearch.index.translog.RemoteTranslogStats;
 import org.opensearch.index.translog.TestTranslog;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogStats;
 import org.opensearch.indices.IndicesQueryCache;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
@@ -142,6 +159,7 @@
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.store.MockFSDirectoryFactory;
 import org.opensearch.threadpool.ThreadPool;
+import org.junit.Assert;
 
 import java.io.IOException;
 import java.nio.charset.Charset;
@@ -152,12 +170,14 @@
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.UUID;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CyclicBarrier;
@@ -178,6 +198,12 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
+import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
+import static org.opensearch.common.lucene.Lucene.cleanLuceneIndex;
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
+import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
+import static org.opensearch.test.hamcrest.RegexMatcher.matches;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.either;
@@ -197,12 +223,7 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.oneOf;
 import static org.hamcrest.Matchers.sameInstance;
-import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
-import static org.opensearch.common.lucene.Lucene.cleanLuceneIndex;
-import static org.opensearch.common.xcontent.ToXContent.EMPTY_PARAMS;
-import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
-import static org.opensearch.test.hamcrest.RegexMatcher.matches;
+import static org.mockito.Mockito.mock;
 
 /**
  * Simple unit-test IndexShard related operations.
@@ -277,7 +298,7 @@ public void testFailShard() throws Exception {
         assertNotNull(shardPath);
         // fail shard
         shard.failShard("test shard fail", new CorruptIndexException("", ""));
-        shard.close("do not assert history", false);
+        shard.close("do not assert history", false, false);
         shard.store().close();
         // check state file still exists
         ShardStateMetadata shardStateMetadata = load(logger, shardPath.getShardStatePath());
@@ -317,23 +338,42 @@ public void testShardStateMetaHashCodeEquals() {
         ShardStateMetadata meta = new ShardStateMetadata(
             randomBoolean(),
             randomRealisticUnicodeOfCodepointLengthBetween(1, 10),
-            allocationId
+            allocationId,
+            randomFrom(ShardStateMetadata.IndexDataLocation.values())
         );
 
-        assertEquals(meta, new ShardStateMetadata(meta.primary, meta.indexUUID, meta.allocationId));
-        assertEquals(meta.hashCode(), new ShardStateMetadata(meta.primary, meta.indexUUID, meta.allocationId).hashCode());
+        assertEquals(meta, new ShardStateMetadata(meta.primary, meta.indexUUID, meta.allocationId, meta.indexDataLocation));
+        assertEquals(
+            meta.hashCode(),
+            new ShardStateMetadata(meta.primary, meta.indexUUID, meta.allocationId, meta.indexDataLocation).hashCode()
+        );
 
-        assertFalse(meta.equals(new ShardStateMetadata(!meta.primary, meta.indexUUID, meta.allocationId)));
-        assertFalse(meta.equals(new ShardStateMetadata(!meta.primary, meta.indexUUID + "foo", meta.allocationId)));
-        assertFalse(meta.equals(new ShardStateMetadata(!meta.primary, meta.indexUUID + "foo", randomAllocationId())));
+        assertNotEquals(meta, new ShardStateMetadata(!meta.primary, meta.indexUUID, meta.allocationId, meta.indexDataLocation));
+        assertNotEquals(meta, new ShardStateMetadata(!meta.primary, meta.indexUUID + "foo", meta.allocationId, meta.indexDataLocation));
+        assertNotEquals(meta, new ShardStateMetadata(!meta.primary, meta.indexUUID, randomAllocationId(), meta.indexDataLocation));
+        assertNotEquals(
+            meta,
+            new ShardStateMetadata(
+                !meta.primary,
+                meta.indexUUID,
+                randomAllocationId(),
+                meta.indexDataLocation == ShardStateMetadata.IndexDataLocation.LOCAL
+                    ? ShardStateMetadata.IndexDataLocation.REMOTE
+                    : ShardStateMetadata.IndexDataLocation.LOCAL
+            )
+        );
         Set<Integer> hashCodes = new HashSet<>();
         for (int i = 0; i < 30; i++) { // just a sanity check that we impl hashcode
             allocationId = randomBoolean() ? null : randomAllocationId();
-            meta = new ShardStateMetadata(randomBoolean(), randomRealisticUnicodeOfCodepointLengthBetween(1, 10), allocationId);
+            meta = new ShardStateMetadata(
+                randomBoolean(),
+                randomRealisticUnicodeOfCodepointLengthBetween(1, 10),
+                allocationId,
+                randomFrom(ShardStateMetadata.IndexDataLocation.values())
+            );
             hashCodes.add(meta.hashCode());
         }
         assertTrue("more than one unique hashcode expected but got: " + hashCodes.size(), hashCodes.size() > 1);
-
     }
 
     public void testClosesPreventsNewOperations() throws Exception {
@@ -906,12 +946,6 @@ public void onResponse(final Releasable releasable) {
         closeShards(indexShard);
     }
 
-    private Releasable acquirePrimaryOperationPermitBlockingly(IndexShard indexShard) throws ExecutionException, InterruptedException {
-        PlainActionFuture<Releasable> fut = new PlainActionFuture<>();
-        indexShard.acquirePrimaryOperationPermit(fut, ThreadPool.Names.WRITE, "");
-        return fut.get();
-    }
-
     private Releasable acquireReplicaOperationPermitBlockingly(IndexShard indexShard, long opPrimaryTerm) throws ExecutionException,
         InterruptedException {
         PlainActionFuture<Releasable> fut = new PlainActionFuture<>();
@@ -964,7 +998,7 @@ public void testOperationPermitOnReplicaShards() throws Exception {
                     AllocationId.newRelocation(routing.allocationId())
                 );
                 IndexShardTestCase.updateRoutingEntry(indexShard, routing);
-                indexShard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+                indexShard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
                 engineClosed = false;
                 break;
             }
@@ -1209,7 +1243,8 @@ public void testGlobalCheckpointSync() throws IOException {
             null,
             new InternalEngineFactory(),
             () -> synced.set(true),
-            RetentionLeaseSyncer.EMPTY
+            RetentionLeaseSyncer.EMPTY,
+            null
         );
         // add a replica
         recoverShardFromStore(primaryShard);
@@ -1283,7 +1318,8 @@ public void testClosedIndicesSkipSyncGlobalCheckpoint() throws Exception {
             null,
             new InternalEngineFactory(),
             () -> synced.set(true),
-            RetentionLeaseSyncer.EMPTY
+            RetentionLeaseSyncer.EMPTY,
+            null
         );
         recoverShardFromStore(primaryShard);
         IndexShard replicaShard = newShard(shardId, false);
@@ -1525,7 +1561,7 @@ public void testSnapshotStore() throws IOException {
         snapshot = newShard.snapshotStoreMetadata();
         assertThat(snapshot.getSegmentsFile().name(), equalTo("segments_3"));
 
-        newShard.close("test", false);
+        newShard.close("test", false, false);
 
         snapshot = newShard.snapshotStoreMetadata();
         assertThat(snapshot.getSegmentsFile().name(), equalTo("segments_3"));
@@ -1611,7 +1647,7 @@ public void testShardStats() throws IOException {
         builder.startObject();
         stats.toXContent(builder, EMPTY_PARAMS);
         builder.endObject();
-        String xContent = Strings.toString(builder);
+        String xContent = builder.toString();
         StringBuilder expectedSubSequence = new StringBuilder("\"shard_path\":{\"state_path\":\"");
         expectedSubSequence.append(shard.shardPath().getRootStatePath().toString());
         expectedSubSequence.append("\",\"data_path\":\"");
@@ -1682,7 +1718,7 @@ public Set<String> getPendingDeletions() throws IOException {
             }
         };
 
-        try (Store store = createStore(shardId, new IndexSettings(metadata, Settings.EMPTY), directory)) {
+        try (Store store = createStore(shardId, new IndexSettings(metadata, Settings.EMPTY), directory, shardPath)) {
             IndexShard shard = newShard(
                 shardRouting,
                 shardPath,
@@ -1693,7 +1729,8 @@ public Set<String> getPendingDeletions() throws IOException {
                 new EngineConfigFactory(new IndexSettings(metadata, metadata.getSettings())),
                 () -> {},
                 RetentionLeaseSyncer.EMPTY,
-                EMPTY_EVENT_LISTENER
+                EMPTY_EVENT_LISTENER,
+                null
             );
             AtomicBoolean failureCallbackTriggered = new AtomicBoolean(false);
             shard.addShardFailureCallback((ig) -> failureCallbackTriggered.set(true));
@@ -1717,6 +1754,34 @@ public Set<String> getPendingDeletions() throws IOException {
         }
     }
 
+    public void testShardStatsWithRemoteStoreEnabled() throws IOException {
+        IndexShard shard = newStartedShard(
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, "SEGMENT")
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .build()
+        );
+        RemoteSegmentTransferTracker remoteSegmentTransferTracker = shard.getRemoteStoreStatsTrackerFactory()
+            .getRemoteSegmentTransferTracker(shard.shardId);
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = shard.getRemoteStoreStatsTrackerFactory()
+            .getRemoteTranslogTransferTracker(shard.shardId);
+        populateSampleRemoteSegmentStats(remoteSegmentTransferTracker);
+        populateSampleRemoteTranslogStats(remoteTranslogTransferTracker);
+        ShardStats shardStats = new ShardStats(
+            shard.routingEntry(),
+            shard.shardPath(),
+            new CommonStats(new IndicesQueryCache(Settings.EMPTY), shard, new CommonStatsFlags()),
+            shard.commitStats(),
+            shard.seqNoStats(),
+            shard.getRetentionLeaseStats()
+        );
+        RemoteSegmentStats remoteSegmentStats = shardStats.getStats().getSegments().getRemoteSegmentStats();
+        assertRemoteSegmentStats(remoteSegmentTransferTracker, remoteSegmentStats);
+        RemoteTranslogStats remoteTranslogStats = shardStats.getStats().getTranslog().getRemoteTranslogStats();
+        assertRemoteTranslogStats(remoteTranslogTransferTracker, remoteTranslogStats);
+        closeShards(shard);
+    }
+
     public void testRefreshMetric() throws IOException {
         IndexShard shard = newStartedShard();
         // refresh on: finalize and end of recovery
@@ -1784,7 +1849,7 @@ public void testIndexingOperationsListeners() throws IOException {
         AtomicInteger preDelete = new AtomicInteger();
         AtomicInteger postDelete = new AtomicInteger();
         AtomicInteger postDeleteException = new AtomicInteger();
-        shard.close("simon says", true);
+        shard.close("simon says", true, false);
         shard = reinitShard(shard, new IndexingOperationListener() {
             @Override
             public Engine.Index preIndex(ShardId shardId, Engine.Index operation) {
@@ -1871,7 +1936,7 @@ public void postDelete(ShardId shardId, Engine.Delete delete, Exception ex) {
         assertEquals(1, postDelete.get());
         assertEquals(0, postDeleteException.get());
 
-        shard.close("Unexpected close", true);
+        shard.close("Unexpected close", true, false);
         shard.state = IndexShardState.STARTED; // It will generate exception
 
         try {
@@ -1914,7 +1979,7 @@ public void testLockingBeforeAndAfterRelocated() throws Exception {
         Thread recoveryThread = new Thread(() -> {
             latch.countDown();
             try {
-                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
@@ -1946,7 +2011,11 @@ public void testDelayedOperationsBeforeAndAfterRelocated() throws Exception {
         Thread recoveryThread = new Thread(() -> {
             try {
                 startRecovery.await();
-                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> relocationStarted.countDown());
+                shard.relocated(
+                    routing.getTargetRelocatingShard().allocationId().getId(),
+                    primaryContext -> relocationStarted.countDown(),
+                    () -> {}
+                );
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
@@ -2034,7 +2103,7 @@ public void run() {
         AtomicBoolean relocated = new AtomicBoolean();
         final Thread recoveryThread = new Thread(() -> {
             try {
-                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
@@ -2069,12 +2138,27 @@ public void testRelocatedShardCanNotBeRevived() throws IOException, InterruptedE
         final ShardRouting originalRouting = shard.routingEntry();
         final ShardRouting routing = ShardRoutingHelper.relocate(originalRouting, "other_node");
         IndexShardTestCase.updateRoutingEntry(shard, routing);
-        shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+        shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
         expectThrows(IllegalIndexShardStateException.class, () -> IndexShardTestCase.updateRoutingEntry(shard, originalRouting));
         closeShards(shard);
     }
 
-    public void testShardCanNotBeMarkedAsRelocatedIfRelocationCancelled() throws IOException {
+    public void testRelocatedSegRepError() throws IOException, InterruptedException {
+        final IndexShard shard = newStartedShard(true);
+        final ShardRouting originalRouting = shard.routingEntry();
+        final ShardRouting routing = ShardRoutingHelper.relocate(originalRouting, "other_node");
+        IndexShardTestCase.updateRoutingEntry(shard, routing);
+        ReplicationFailedException segRepException = expectThrows(
+            ReplicationFailedException.class,
+            () -> shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {
+                throw new ReplicationFailedException("Segment replication failed");
+            })
+        );
+        assertTrue(segRepException.getMessage().equals("Segment replication failed"));
+        closeShards(shard);
+    }
+
+    public void testShardCanNotBeMarkedAsRelocatedIfRelocationCancelled() throws IOException, InterruptedException {
         final IndexShard shard = newStartedShard(true);
         final ShardRouting originalRouting = shard.routingEntry();
         final ShardRouting relocationRouting = ShardRoutingHelper.relocate(originalRouting, "other_node");
@@ -2082,7 +2166,7 @@ public void testShardCanNotBeMarkedAsRelocatedIfRelocationCancelled() throws IOE
         IndexShardTestCase.updateRoutingEntry(shard, originalRouting);
         expectThrows(
             IllegalIndexShardStateException.class,
-            () -> shard.relocated(relocationRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {})
+            () -> shard.relocated(relocationRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {})
         );
         closeShards(shard);
     }
@@ -2103,7 +2187,7 @@ public void onFailure(Exception e) {
             @Override
             protected void doRun() throws Exception {
                 cyclicBarrier.await();
-                shard.relocated(relocationRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+                shard.relocated(relocationRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
             }
         });
         relocationThread.start();
@@ -2151,9 +2235,10 @@ public void testRelocateMissingTarget() throws Exception {
         final ShardRouting toNode2 = ShardRoutingHelper.relocate(original, "node_2");
         IndexShardTestCase.updateRoutingEntry(shard, toNode2);
         final AtomicBoolean relocated = new AtomicBoolean();
+
         final IllegalStateException error = expectThrows(
             IllegalStateException.class,
-            () -> shard.relocated(toNode1.getTargetRelocatingShard().allocationId().getId(), ctx -> relocated.set(true))
+            () -> shard.relocated(toNode1.getTargetRelocatingShard().allocationId().getId(), ctx -> relocated.set(true), () -> {})
         );
         assertThat(
             error.getMessage(),
@@ -2163,8 +2248,9 @@ public void testRelocateMissingTarget() throws Exception {
                     + "] is no longer part of the replication group"
             )
         );
+
         assertFalse(relocated.get());
-        shard.relocated(toNode2.getTargetRelocatingShard().allocationId().getId(), ctx -> relocated.set(true));
+        shard.relocated(toNode2.getTargetRelocatingShard().allocationId().getId(), ctx -> relocated.set(true), () -> {});
         assertTrue(relocated.get());
         closeShards(shard);
     }
@@ -2187,38 +2273,42 @@ public void testRecoverFromStoreWithOutOfOrderDelete() throws IOException {
         shard.applyDeleteOperationOnReplica(1, primaryTerm, 2, "id");
         shard.getEngine().rollTranslogGeneration(); // isolate the delete in it's own generation
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             0,
             primaryTerm,
             1,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(shard.shardId().getIndexName(), "id", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(shard.shardId().getIndexName(), "id", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             3,
             primaryTerm,
             3,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(shard.shardId().getIndexName(), "id-3", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(shard.shardId().getIndexName(), "id-3", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         // Flushing a new commit with local checkpoint=1 allows to skip the translog gen #1 in recovery.
         shard.flush(new FlushRequest().force(true).waitIfOngoing(true));
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             2,
             primaryTerm,
             3,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(shard.shardId().getIndexName(), "id-2", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(shard.shardId().getIndexName(), "id-2", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             5,
             primaryTerm,
             1,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(shard.shardId().getIndexName(), "id-5", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(shard.shardId().getIndexName(), "id-5", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         shard.sync(); // advance local checkpoint
 
@@ -2358,8 +2448,9 @@ public void testRecoverFromStoreWithNoOps() throws IOException {
         // start a replica shard and index the second doc
         final IndexShard otherShard = newStartedShard(false);
         updateMappings(otherShard, shard.indexSettings().getIndexMetadata());
-        SourceToParse sourceToParse = new SourceToParse(shard.shardId().getIndexName(), "1", new BytesArray("{}"), XContentType.JSON);
+        SourceToParse sourceToParse = new SourceToParse(shard.shardId().getIndexName(), "1", new BytesArray("{}"), MediaTypeRegistry.JSON);
         otherShard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             1,
             otherShard.getOperationPrimaryTerm(),
             1,
@@ -2487,34 +2578,37 @@ public void testRecoverFromStoreRemoveStaleOperations() throws Exception {
         final String indexName = shard.shardId().getIndexName();
         // Index #0, index #1
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             0,
             primaryTerm,
             1,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(indexName, "doc-0", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(indexName, "doc-0", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         flushShard(shard);
         shard.updateGlobalCheckpointOnReplica(0, "test"); // stick the global checkpoint here.
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             1,
             primaryTerm,
             1,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(indexName, "doc-1", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(indexName, "doc-1", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         flushShard(shard);
         assertThat(getShardDocUIDs(shard), containsInAnyOrder("doc-0", "doc-1"));
         shard.getEngine().rollTranslogGeneration();
         shard.markSeqNoAsNoop(1, primaryTerm, "test");
         shard.applyIndexOperationOnReplica(
+            UUID.randomUUID().toString(),
             2,
             primaryTerm,
             1,
             IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
             false,
-            new SourceToParse(indexName, "doc-2", new BytesArray("{}"), XContentType.JSON)
+            new SourceToParse(indexName, "doc-2", new BytesArray("{}"), MediaTypeRegistry.JSON)
         );
         flushShard(shard);
         assertThat(getShardDocUIDs(shard), containsInAnyOrder("doc-0", "doc-1", "doc-2"));
@@ -2541,7 +2635,8 @@ public void testRecoverFromStoreRemoveStaleOperations() throws Exception {
             shard.getEngineConfigFactory(),
             shard.getGlobalCheckpointSyncer(),
             shard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
         DiscoveryNode localNode = new DiscoveryNode("foo", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         newShard.markAsRecovering("store", new RecoveryState(newShard.routingEntry(), localNode, null));
@@ -2556,7 +2651,7 @@ public void testRecoveryFailsAfterMovingToRelocatedState() throws InterruptedExc
         assertThat(shard.state(), equalTo(IndexShardState.STARTED));
         ShardRouting inRecoveryRouting = ShardRoutingHelper.relocate(origRouting, "some_node");
         IndexShardTestCase.updateRoutingEntry(shard, inRecoveryRouting);
-        shard.relocated(inRecoveryRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {});
+        shard.relocated(inRecoveryRouting.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
         assertTrue(shard.isRelocatedPrimary());
         try {
             IndexShardTestCase.updateRoutingEntry(shard, origRouting);
@@ -2566,6 +2661,40 @@ public void testRecoveryFailsAfterMovingToRelocatedState() throws InterruptedExc
         closeShards(shard);
     }
 
+    public void testRelocatedForRemoteTranslogBackedIndexWithAsyncDurability() throws IOException {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "seg-test")
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "txlog-test")
+            .put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Translog.Durability.ASYNC)
+            .build();
+        final IndexShard indexShard = newStartedShard(true, settings, new NRTReplicationEngineFactory());
+        ShardRouting routing = indexShard.routingEntry();
+        routing = newShardRouting(
+            routing.shardId(),
+            routing.currentNodeId(),
+            "otherNode",
+            true,
+            ShardRoutingState.RELOCATING,
+            AllocationId.newRelocation(routing.allocationId())
+        );
+        IndexShardTestCase.updateRoutingEntry(indexShard, routing);
+        assertTrue(indexShard.isSyncNeeded());
+        try {
+            indexShard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+        assertTrue(indexShard.isRelocatedPrimary());
+        assertFalse(indexShard.isSyncNeeded());
+        assertFalse(indexShard.getReplicationTracker().isPrimaryMode());
+        closeShards(indexShard);
+    }
+
     public void testRestoreShard() throws IOException {
         final IndexShard source = newStartedShard(true);
         IndexShard target = newStartedShard(true);
@@ -2643,6 +2772,170 @@ public void restoreShard(
         closeShards(target);
     }
 
+    public void testSyncSegmentsFromGivenRemoteSegmentStore() throws IOException {
+        String remoteStorePath = createTempDir().toString();
+        IndexShard source = newStartedShard(
+            true,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, remoteStorePath + "__test")
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, remoteStorePath + "__test")
+                .build(),
+            new InternalEngineFactory()
+        );
+        indexDoc(source, "_doc", "1");
+        indexDoc(source, "_doc", "2");
+        source.refresh("test");
+        assertDocs(source, "1", "2");
+        indexDoc(source, "_doc", "3");
+        source.refresh("test");
+        flushShard(source);
+
+        indexDoc(source, "_doc", "5");
+        source.refresh("test");
+
+        indexDoc(source, "_doc", "4");
+        source.refresh("test");
+
+        long primaryTerm;
+        long commitGeneration;
+        try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = source.getSegmentInfosSnapshot()) {
+            SegmentInfos segmentInfos = segmentInfosGatedCloseable.get();
+            primaryTerm = source.getOperationPrimaryTerm();
+            commitGeneration = segmentInfos.getGeneration();
+        }
+        Collection<String> lastCommitedSegmentsInSource = SegmentInfos.readLatestCommit(source.store().directory()).files(false);
+
+        closeShards(source);
+
+        RemoteSegmentStoreDirectory tempRemoteSegmentDirectory = createRemoteSegmentStoreDirectory(
+            source.shardId(),
+            PathUtils.get(remoteStorePath)
+        );
+
+        IndexShard target = newStartedShard(
+            true,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, remoteStorePath + "__test1")
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, remoteStorePath + "__test1")
+                .build(),
+            new InternalEngineFactory()
+        );
+        ShardRouting routing = ShardRoutingHelper.initWithSameId(
+            target.routingEntry(),
+            RecoverySource.ExistingStoreRecoverySource.INSTANCE
+        );
+        routing = ShardRoutingHelper.newWithRestoreSource(routing, new RecoverySource.EmptyStoreRecoverySource());
+
+        target = reinitShard(target, routing);
+
+        target.syncSegmentsFromGivenRemoteSegmentStore(false, tempRemoteSegmentDirectory, primaryTerm, commitGeneration);
+        RemoteSegmentStoreDirectory remoteStoreDirectory = ((RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) target
+            .remoteStore()
+            .directory()).getDelegate()).getDelegate());
+        Collection<String> uploadFiles = remoteStoreDirectory.getSegmentsUploadedToRemoteStore().keySet();
+        assertTrue(uploadFiles.containsAll(lastCommitedSegmentsInSource));
+        assertTrue(
+            "Failed to sync all files to new shard",
+            List.of(target.store().directory().listAll()).containsAll(lastCommitedSegmentsInSource)
+        );
+        Directory storeDirectory = ((FilterDirectory) ((FilterDirectory) target.store().directory()).getDelegate()).getDelegate();
+        ((BaseDirectoryWrapper) storeDirectory).setCheckIndexOnClose(false);
+        closeShards(target);
+    }
+
+    public void testRefreshLevelRestoreShardFromRemoteStore() throws IOException {
+        testRestoreShardFromRemoteStore(false);
+    }
+
+    public void testCommitLevelRestoreShardFromRemoteStore() throws IOException {
+        testRestoreShardFromRemoteStore(true);
+    }
+
+    public void testRestoreShardFromRemoteStore(boolean performFlush) throws IOException {
+        String remoteStorePath = createTempDir().toString();
+        IndexShard target = newStartedShard(
+            true,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, remoteStorePath + "__test")
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, remoteStorePath + "__test")
+                .build(),
+            new InternalEngineFactory()
+        );
+
+        indexDoc(target, "_doc", "1");
+        indexDoc(target, "_doc", "2");
+        target.refresh("test");
+        assertDocs(target, "1", "2");
+        if (performFlush) {
+            flushShard(target);
+        }
+
+        ShardRouting routing = ShardRoutingHelper.initWithSameId(
+            target.routingEntry(),
+            RecoverySource.ExistingStoreRecoverySource.INSTANCE
+        );
+        routing = ShardRoutingHelper.newWithRestoreSource(
+            routing,
+            new RecoverySource.RemoteStoreRecoverySource(
+                UUIDs.randomBase64UUID(),
+                Version.CURRENT,
+                new IndexId("test", UUIDs.randomBase64UUID(random()))
+            )
+        );
+
+        // Delete files in store directory to restore from remote directory
+        Directory storeDirectory = target.store().directory();
+
+        for (String file : storeDirectory.listAll()) {
+            storeDirectory.deleteFile(file);
+            // Windows has buggy File delete logic where AccessDeniedExceptions
+            // are thrown when there is an open file handle on a particular file. FSDirectory attempts to resolve this with hacks by
+            // swallowing the exceptions and moving the file to a pending delete state
+            // to retry in the future while being filtered from listAll invocations.
+            // However, this logic is also buggy and after the first delete attempt we are left in a state where the file is still on disk
+            // and not pending delete.
+            // A second attempt to delete the file will properly move it to pending deletion, and be filtered from listAll.
+            if (Arrays.asList(storeDirectory.listAll()).contains(file) && storeDirectory.getPendingDeletions().contains(file) == false) {
+                logger.info("File {} was not deleted and is not pending delete, attempting delete again...", file);
+                storeDirectory.deleteFile(file);
+                assertTrue(storeDirectory.getPendingDeletions().contains(file));
+            }
+        }
+
+        assertEquals(0, storeDirectory.listAll().length);
+
+        Directory remoteDirectory = ((FilterDirectory) ((FilterDirectory) target.remoteStore().directory()).getDelegate()).getDelegate();
+
+        // extra0 file is added as a part of https://lucene.apache.org/core/7_2_1/test-framework/org/apache/lucene/mockfile/ExtrasFS.html
+        // Safe to remove without impacting the test
+        for (String file : remoteDirectory.listAll()) {
+            if (ExtrasFS.isExtra(file)) {
+                remoteDirectory.deleteFile(file);
+            }
+        }
+
+        target.remoteStore().incRef();
+        target = reinitShard(target, routing);
+
+        DiscoveryNode localNode = new DiscoveryNode("foo", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
+        target.markAsRecovering("remote_store", new RecoveryState(routing, localNode, null));
+        final PlainActionFuture<Boolean> future = PlainActionFuture.newFuture();
+        target.restoreFromRemoteStore(future);
+        target.remoteStore().decRef();
+        assertTrue(future.actionGet());
+        assertDocs(target, "1", "2");
+
+        storeDirectory = ((FilterDirectory) ((FilterDirectory) target.store().directory()).getDelegate()).getDelegate();
+        ((BaseDirectoryWrapper) storeDirectory).setCheckIndexOnClose(false);
+        closeShards(target);
+    }
+
     public void testReaderWrapperIsUsed() throws IOException {
         IndexShard shard = newStartedShard(true);
         indexDoc(shard, "_doc", "0", "{\"foo\" : \"bar\"}");
@@ -2671,7 +2964,8 @@ public void testReaderWrapperIsUsed() throws IOException {
             shard.getEngineConfigFactory(),
             () -> {},
             RetentionLeaseSyncer.EMPTY,
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         recoverShardFromStore(newShard);
@@ -2726,11 +3020,9 @@ public void testReaderWrapperWorksWithGlobalOrdinals() throws IOException {
             new NoneCircuitBreakerService(),
             shard.mapperService()
         );
-        IndexFieldData.Global ifd = indexFieldDataService.getForField(
-            foo,
-            "test",
-            () -> { throw new UnsupportedOperationException("search lookup not available"); }
-        );
+        IndexFieldData.Global ifd = indexFieldDataService.getForField(foo, "test", () -> {
+            throw new UnsupportedOperationException("search lookup not available");
+        });
         FieldDataStats before = shard.fieldData().stats("foo");
         assertThat(before.getMemorySizeInBytes(), equalTo(0L));
         FieldDataStats after = null;
@@ -2821,7 +3113,8 @@ public void testSearchIsReleaseIfWrapperFails() throws IOException {
             shard.getEngineConfigFactory(),
             () -> {},
             RetentionLeaseSyncer.EMPTY,
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         recoverShardFromStore(newShard);
@@ -3139,7 +3432,7 @@ public void testRecoverFromLocalShard() throws IOException {
             RecoveryState recoveryState = targetShard.recoveryState();
             assertEquals(RecoveryState.Stage.DONE, recoveryState.getStage());
             assertTrue(recoveryState.getIndex().fileDetails().size() > 0);
-            for (RecoveryState.FileDetail file : recoveryState.getIndex().fileDetails()) {
+            for (ReplicationLuceneIndex.FileMetadata file : recoveryState.getIndex().fileDetails()) {
                 if (file.reused()) {
                     assertEquals(file.recovered(), 0);
                 } else {
@@ -3310,14 +3603,13 @@ public void testEstimateTotalDocSize() throws Exception {
 
             int numDoc = randomIntBetween(100, 200);
             for (int i = 0; i < numDoc; i++) {
-                String doc = Strings.toString(
-                    XContentFactory.jsonBuilder()
-                        .startObject()
-                        .field("count", randomInt())
-                        .field("point", randomFloat())
-                        .field("description", randomUnicodeOfCodepointLength(100))
-                        .endObject()
-                );
+                String doc = XContentFactory.jsonBuilder()
+                    .startObject()
+                    .field("count", randomInt())
+                    .field("point", randomFloat())
+                    .field("description", randomUnicodeOfCodepointLength(100))
+                    .endObject()
+                    .toString();
                 indexDoc(indexShard, "_doc", Integer.toString(i), doc);
             }
 
@@ -3424,6 +3716,28 @@ public void testReadSnapshotConcurrently() throws IOException, InterruptedExcept
         closeShards(newShard);
     }
 
+    /**
+     * here we are mocking a SegmentReplicationcheckpointPublisher and testing on index shard if CheckpointRefreshListener is added to the InternalrefreshListerners List
+     */
+    public void testCheckpointRefreshListener() throws IOException {
+        final SegmentReplicationCheckpointPublisher mock = mock(SegmentReplicationCheckpointPublisher.class);
+        IndexShard shard = newStartedShard(p -> newShard(true, mock), true);
+        List<ReferenceManager.RefreshListener> refreshListeners = shard.getEngine().config().getInternalRefreshListener();
+        assertTrue(refreshListeners.stream().anyMatch(e -> e instanceof CheckpointRefreshListener));
+        closeShards(shard);
+    }
+
+    /**
+     * here we are passing null in place of SegmentReplicationCheckpointPublisher and testing  on index shard if CheckpointRefreshListener is not added to the InternalrefreshListerners List
+     */
+    public void testCheckpointRefreshListenerWithNull() throws IOException {
+        final SegmentReplicationCheckpointPublisher publisher = null;
+        IndexShard shard = newStartedShard(p -> newShard(true, publisher), true);
+        List<ReferenceManager.RefreshListener> refreshListeners = shard.getEngine().config().getInternalRefreshListener();
+        assertFalse(refreshListeners.stream().anyMatch(e -> e instanceof CheckpointRefreshListener));
+        closeShards(shard);
+    }
+
     public void testIndexCheckOnStartup() throws Exception {
         final IndexShard indexShard = newStartedShard(true);
 
@@ -3476,7 +3790,8 @@ public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IO
             indexShard.engineConfigFactory,
             indexShard.getGlobalCheckpointSyncer(),
             indexShard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         final IndexShardRecoveryException indexShardRecoveryException = expectThrows(
@@ -3533,7 +3848,8 @@ public void testShardDoesNotStartIfCorruptedMarkerIsPresent() throws Exception {
             indexShard.engineConfigFactory,
             indexShard.getGlobalCheckpointSyncer(),
             indexShard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         final IndexShardRecoveryException exception1 = expectThrows(
@@ -3567,7 +3883,8 @@ public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IO
             indexShard.engineConfigFactory,
             indexShard.getGlobalCheckpointSyncer(),
             indexShard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         final IndexShardRecoveryException exception2 = expectThrows(
@@ -3621,7 +3938,8 @@ public void testReadSnapshotAndCheckIndexConcurrently() throws Exception {
             indexShard.engineConfigFactory,
             indexShard.getGlobalCheckpointSyncer(),
             indexShard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
 
         Store.MetadataSnapshot storeFileMetadatas = newShard.snapshotStoreMetadata();
@@ -3703,9 +4021,10 @@ private Result indexOnReplicaWithGaps(final IndexShard indexShard, final int ope
                     indexShard.shardId().getIndexName(),
                     id,
                     new BytesArray("{}"),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 );
                 indexShard.applyIndexOperationOnReplica(
+                    UUID.randomUUID().toString(),
                     i,
                     indexShard.getOperationPrimaryTerm(),
                     1,
@@ -4051,7 +4370,7 @@ public InternalEngine recoverFromTranslog(TranslogRecoveryRunner translogRecover
         Thread closeShardThread = new Thread(() -> {
             try {
                 readyToCloseLatch.await();
-                shard.close("testing", false);
+                shard.close("testing", false, false);
                 // in integration tests, this is done as a listener on IndexService.
                 MockFSDirectoryFactory.checkIndex(logger, shard.store(), shard.shardId);
             } catch (InterruptedException | IOException e) {
@@ -4097,14 +4416,14 @@ public void testSnapshotWhileResettingEngine() throws Exception {
             @Override
             public InternalEngine recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo)
                 throws IOException {
-                InternalEngine internalEngine = super.recoverFromTranslog(translogRecoveryRunner, recoverUpToSeqNo);
+                InternalEngine engine = super.recoverFromTranslog(translogRecoveryRunner, recoverUpToSeqNo);
                 readyToSnapshotLatch.countDown();
                 try {
                     snapshotDoneLatch.await();
                 } catch (InterruptedException e) {
                     throw new AssertionError(e);
                 }
-                return internalEngine;
+                return engine;
             }
         });
 
@@ -4335,12 +4654,13 @@ public void testDoNotTrimCommitsWhenOpenReadOnlyEngine() throws Exception {
                 seqNo++; // create gaps in sequence numbers
             }
             shard.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 seqNo,
                 shard.getOperationPrimaryTerm(),
                 1,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(shard.shardId.getIndexName(), Long.toString(i), new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(shard.shardId.getIndexName(), Long.toString(i), new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             shard.updateGlobalCheckpointOnReplica(shard.getLocalCheckpoint(), "test");
             if (randomInt(100) < 10) {
@@ -4368,7 +4688,8 @@ protected void ensureMaxSeqNoEqualsToGlobalCheckpoint(SeqNoStats seqNoStats) {
                     // just like a following shard, we need to skip this check for now.
                 }
             },
-            shard.getEngineConfigFactory()
+            shard.getEngineConfigFactory(),
+            null
         );
         DiscoveryNode localNode = new DiscoveryNode("foo", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
         readonlyShard.markAsRecovering("store", new RecoveryState(readonlyShard.routingEntry(), localNode, null));
@@ -4377,6 +4698,88 @@ protected void ensureMaxSeqNoEqualsToGlobalCheckpoint(SeqNoStats seqNoStats) {
         closeShards(readonlyShard);
     }
 
+    public void testReadOnlyReplicaEngineConfig() throws IOException {
+        Settings primarySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .build();
+        final IndexShard primaryShard = newStartedShard(false, primarySettings, new NRTReplicationEngineFactory());
+        assertFalse(primaryShard.getEngine().config().isReadOnlyReplica());
+        assertEquals(primaryShard.getEngine().getClass(), InternalEngine.class);
+
+        Settings replicaSettings = Settings.builder()
+            .put(primarySettings)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        final IndexShard replicaShard = newStartedShard(false, replicaSettings, new NRTReplicationEngineFactory());
+        assertTrue(replicaShard.getEngine().config().isReadOnlyReplica());
+        assertEquals(replicaShard.getEngine().getClass(), NRTReplicationEngine.class);
+
+        closeShards(primaryShard, replicaShard);
+    }
+
+    public void testTranslogFactoryWithoutRemoteStore() throws IOException {
+        Settings primarySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .build();
+        final IndexShard primaryShard = newStartedShard(true, primarySettings, new NRTReplicationEngineFactory());
+        assertEquals(primaryShard.getEngine().getClass(), InternalEngine.class);
+        assertEquals(primaryShard.getEngine().config().getTranslogFactory().getClass(), InternalTranslogFactory.class);
+
+        final IndexShard replicaShard = newStartedShard(true, primarySettings, new NRTReplicationEngineFactory());
+        assertEquals(replicaShard.getEngine().getClass(), InternalEngine.class);
+        assertEquals(replicaShard.getEngine().config().getTranslogFactory().getClass(), InternalTranslogFactory.class);
+
+        closeShards(primaryShard, replicaShard);
+    }
+
+    public void testTranslogFactoryForReplicaShardWithoutRemoteStore() throws IOException {
+        Settings primarySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .build();
+        final IndexShard primaryShard = newStartedShard(false, primarySettings, new NRTReplicationEngineFactory());
+        assertEquals(primaryShard.getEngine().getClass(), InternalEngine.class);
+        assertEquals(primaryShard.getEngine().config().getTranslogFactory().getClass(), InternalTranslogFactory.class);
+        closeShards(primaryShard);
+    }
+
+    public void testTranslogFactoryForRemoteTranslogBackedPrimaryShard() throws IOException {
+        Settings primarySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "seg-test")
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "txlog-test")
+            .build();
+        final IndexShard primaryShard = newStartedShard(true, primarySettings, new NRTReplicationEngineFactory());
+        assertEquals(primaryShard.getEngine().getClass(), InternalEngine.class);
+        assertEquals(primaryShard.getEngine().config().getTranslogFactory().getClass(), RemoteBlobStoreInternalTranslogFactory.class);
+        closeShards(primaryShard);
+    }
+
+    public void testTranslogFactoryForRemoteTranslogBackedReplicaShard() throws IOException {
+        Settings primarySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "seg-test")
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "txlog-test")
+            .build();
+        final IndexShard replicaShard = newStartedShard(false, primarySettings, new NRTReplicationEngineFactory());
+        assertEquals(replicaShard.getEngine().getClass(), NRTReplicationEngine.class);
+        assertEquals(replicaShard.getEngine().config().getTranslogFactory().getClass(), InternalTranslogFactory.class);
+        closeShards(replicaShard);
+    }
+
     public void testCloseShardWhileEngineIsWarming() throws Exception {
         CountDownLatch warmerStarted = new CountDownLatch(1);
         CountDownLatch warmerBlocking = new CountDownLatch(1);
@@ -4390,37 +4793,36 @@ public void testCloseShardWhileEngineIsWarming() throws Exception {
                     throw new AssertionError(e);
                 }
             };
-            EngineConfig configWithWarmer = new EngineConfig(
-                config.getShardId(),
-                config.getThreadPool(),
-                config.getIndexSettings(),
-                warmer,
-                config.getStore(),
-                config.getMergePolicy(),
-                config.getAnalyzer(),
-                config.getSimilarity(),
-                new CodecService(null, logger),
-                config.getEventListener(),
-                config.getQueryCache(),
-                config.getQueryCachingPolicy(),
-                config.getTranslogConfig(),
-                config.getFlushMergesAfter(),
-                config.getExternalRefreshListener(),
-                config.getInternalRefreshListener(),
-                config.getIndexSort(),
-                config.getCircuitBreakerService(),
-                config.getGlobalCheckpointSupplier(),
-                config.retentionLeasesSupplier(),
-                config.getPrimaryTermSupplier(),
-                config.getTombstoneDocSupplier()
-            );
+            EngineConfig configWithWarmer = new EngineConfig.Builder().shardId(config.getShardId())
+                .threadPool(config.getThreadPool())
+                .indexSettings(config.getIndexSettings())
+                .warmer(warmer)
+                .store(config.getStore())
+                .mergePolicy(config.getMergePolicy())
+                .analyzer(config.getAnalyzer())
+                .similarity(config.getSimilarity())
+                .codecService(new CodecService(null, config.getIndexSettings(), logger))
+                .eventListener(config.getEventListener())
+                .queryCache(config.getQueryCache())
+                .queryCachingPolicy(config.getQueryCachingPolicy())
+                .translogConfig(config.getTranslogConfig())
+                .flushMergesAfter(config.getFlushMergesAfter())
+                .externalRefreshListener(config.getExternalRefreshListener())
+                .internalRefreshListener(config.getInternalRefreshListener())
+                .indexSort(config.getIndexSort())
+                .circuitBreakerService(config.getCircuitBreakerService())
+                .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+                .retentionLeasesSupplier(config.retentionLeasesSupplier())
+                .primaryTermSupplier(config.getPrimaryTermSupplier())
+                .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+                .build();
             return new InternalEngine(configWithWarmer);
         });
         Thread recoveryThread = new Thread(() -> expectThrows(AlreadyClosedException.class, () -> recoverShardFromStore(shard)));
         recoveryThread.start();
         try {
             warmerStarted.await();
-            shard.close("testing", false);
+            shard.close("testing", false, false);
             assertThat(shard.state, equalTo(IndexShardState.CLOSED));
         } finally {
             warmerBlocking.countDown();
@@ -4446,4 +4848,43 @@ public void testRecordsForceMerges() throws IOException {
         assertThat(thirdForceMergeUUID, equalTo(secondForceMergeRequest.forceMergeUUID()));
         closeShards(shard);
     }
+
+    private void populateSampleRemoteSegmentStats(RemoteSegmentTransferTracker tracker) {
+        tracker.addUploadBytesStarted(30L);
+        tracker.addUploadBytesSucceeded(10L);
+        tracker.addUploadBytesFailed(10L);
+    }
+
+    private void populateSampleRemoteTranslogStats(RemoteTranslogTransferTracker tracker) {
+        tracker.incrementTotalUploadsStarted();
+        tracker.incrementTotalUploadsStarted();
+        tracker.incrementTotalUploadsStarted();
+        tracker.incrementTotalUploadsSucceeded();
+        tracker.incrementTotalUploadsFailed();
+        int bytesStarted = randomIntBetween(100, 1000);
+        tracker.addUploadBytesStarted(bytesStarted);
+        tracker.addUploadBytesSucceeded(randomIntBetween(1, bytesStarted / 2));
+        tracker.addUploadBytesFailed(randomIntBetween(1, bytesStarted / 2));
+    }
+
+    private static void assertRemoteTranslogStats(
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker,
+        RemoteTranslogStats remoteTranslogStats
+    ) {
+        assertEquals(remoteTranslogTransferTracker.getTotalUploadsStarted(), remoteTranslogStats.getTotalUploadsStarted());
+        assertEquals(remoteTranslogTransferTracker.getTotalUploadsSucceeded(), remoteTranslogStats.getTotalUploadsSucceeded());
+        assertEquals(remoteTranslogTransferTracker.getTotalUploadsFailed(), remoteTranslogStats.getTotalUploadsFailed());
+        assertEquals(remoteTranslogTransferTracker.getUploadBytesStarted(), remoteTranslogStats.getUploadBytesStarted());
+        assertEquals(remoteTranslogTransferTracker.getUploadBytesSucceeded(), remoteTranslogStats.getUploadBytesSucceeded());
+        assertEquals(remoteTranslogTransferTracker.getUploadBytesFailed(), remoteTranslogStats.getUploadBytesFailed());
+    }
+
+    private static void assertRemoteSegmentStats(
+        RemoteSegmentTransferTracker remoteSegmentTransferTracker,
+        RemoteSegmentStats remoteSegmentStats
+    ) {
+        assertEquals(remoteSegmentTransferTracker.getUploadBytesStarted(), remoteSegmentStats.getUploadBytesStarted());
+        assertEquals(remoteSegmentTransferTracker.getUploadBytesSucceeded(), remoteSegmentStats.getUploadBytesSucceeded());
+        assertEquals(remoteSegmentTransferTracker.getUploadBytesFailed(), remoteSegmentStats.getUploadBytesFailed());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexingOperationListenerTests.java b/server/src/test/java/org/opensearch/index/shard/IndexingOperationListenerTests.java
index 6ac5f96e11f34..a62b38a6b0063 100644
--- a/server/src/test/java/org/opensearch/index/shard/IndexingOperationListenerTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/IndexingOperationListenerTests.java
@@ -32,7 +32,8 @@
 package org.opensearch.index.shard;
 
 import org.apache.lucene.index.Term;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.InternalEngineTests;
 import org.opensearch.index.mapper.ParsedDocument;
diff --git a/server/src/test/java/org/opensearch/index/shard/IndexingStatsTests.java b/server/src/test/java/org/opensearch/index/shard/IndexingStatsTests.java
new file mode 100644
index 0000000000000..acf482552c260
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/IndexingStatsTests.java
@@ -0,0 +1,141 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class IndexingStatsTests extends OpenSearchTestCase {
+
+    public void testSerialization() throws IOException {
+        IndexingStats stats = createTestInstance();
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            stats.writeTo(out);
+
+            try (StreamInput in = out.bytes().streamInput()) {
+                IndexingStats deserializedStats = new IndexingStats(in);
+
+                if (stats.getTotal() == null) {
+                    assertNull(deserializedStats.getTotal());
+                    return;
+                }
+
+                IndexingStats.Stats totalStats = stats.getTotal();
+                IndexingStats.Stats deserializedTotalStats = deserializedStats.getTotal();
+
+                assertEquals(totalStats.getIndexCount(), deserializedTotalStats.getIndexCount());
+                assertEquals(totalStats.getIndexTime(), deserializedTotalStats.getIndexTime());
+                assertEquals(totalStats.getIndexCurrent(), deserializedTotalStats.getIndexCurrent());
+                assertEquals(totalStats.getIndexFailedCount(), deserializedTotalStats.getIndexFailedCount());
+                assertEquals(totalStats.getDeleteCount(), deserializedTotalStats.getDeleteCount());
+                assertEquals(totalStats.getDeleteTime(), deserializedTotalStats.getDeleteTime());
+                assertEquals(totalStats.getDeleteCurrent(), deserializedTotalStats.getDeleteCurrent());
+                assertEquals(totalStats.getNoopUpdateCount(), deserializedTotalStats.getNoopUpdateCount());
+                assertEquals(totalStats.isThrottled(), deserializedTotalStats.isThrottled());
+                assertEquals(totalStats.getThrottleTime(), deserializedTotalStats.getThrottleTime());
+
+                if (totalStats.getDocStatusStats() == null) {
+                    assertNull(deserializedTotalStats.getDocStatusStats());
+                    return;
+                }
+
+                IndexingStats.Stats.DocStatusStats docStatusStats = totalStats.getDocStatusStats();
+                IndexingStats.Stats.DocStatusStats deserializedDocStatusStats = deserializedTotalStats.getDocStatusStats();
+
+                assertTrue(
+                    Arrays.equals(
+                        docStatusStats.getDocStatusCounter(),
+                        deserializedDocStatusStats.getDocStatusCounter(),
+                        Comparator.comparingLong(AtomicLong::longValue)
+                    )
+                );
+            }
+        }
+    }
+
+    public void testToXContentForIndexingStats() throws IOException {
+        IndexingStats stats = createTestInstance();
+        IndexingStats.Stats totalStats = stats.getTotal();
+        AtomicLong[] counter = totalStats.getDocStatusStats().getDocStatusCounter();
+
+        String expected = "{\"indexing\":{\"index_total\":"
+            + totalStats.getIndexCount()
+            + ",\"index_time_in_millis\":"
+            + totalStats.getIndexTime().getMillis()
+            + ",\"index_current\":"
+            + totalStats.getIndexCurrent()
+            + ",\"index_failed\":"
+            + totalStats.getIndexFailedCount()
+            + ",\"delete_total\":"
+            + totalStats.getDeleteCount()
+            + ",\"delete_time_in_millis\":"
+            + totalStats.getDeleteTime().getMillis()
+            + ",\"delete_current\":"
+            + totalStats.getDeleteCurrent()
+            + ",\"noop_update_total\":"
+            + totalStats.getNoopUpdateCount()
+            + ",\"is_throttled\":"
+            + totalStats.isThrottled()
+            + ",\"throttle_time_in_millis\":"
+            + totalStats.getThrottleTime().getMillis()
+            + ",\"doc_status\":{\"1xx\":"
+            + counter[0]
+            + ",\"2xx\":"
+            + counter[1]
+            + ",\"3xx\":"
+            + counter[2]
+            + ",\"4xx\":"
+            + counter[3]
+            + ",\"5xx\":"
+            + counter[4]
+            + "}}}";
+
+        XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        xContentBuilder.startObject();
+        xContentBuilder = stats.toXContent(xContentBuilder, ToXContent.EMPTY_PARAMS);
+        xContentBuilder.endObject();
+
+        assertEquals(expected, xContentBuilder.toString());
+    }
+
+    private IndexingStats createTestInstance() {
+        IndexingStats.Stats.DocStatusStats docStatusStats = new IndexingStats.Stats.DocStatusStats();
+        for (int i = 1; i < 6; ++i) {
+            docStatusStats.add(RestStatus.fromCode(i * 100), randomNonNegativeLong());
+        }
+
+        IndexingStats.Stats stats = new IndexingStats.Stats(
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            randomBoolean(),
+            randomNonNegativeLong(),
+            docStatusStats
+        );
+
+        return new IndexingStats(stats);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/NewPathForShardTests.java b/server/src/test/java/org/opensearch/index/shard/NewPathForShardTests.java
index 0d2a27aa0714e..3f85256a1094e 100644
--- a/server/src/test/java/org/opensearch/index/shard/NewPathForShardTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/NewPathForShardTests.java
@@ -36,13 +36,14 @@
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeEnvironment.NodePath;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
diff --git a/server/src/test/java/org/opensearch/index/shard/PrimaryReplicaSyncerTests.java b/server/src/test/java/org/opensearch/index/shard/PrimaryReplicaSyncerTests.java
index 631fa384de335..b1bcaac2c1947 100644
--- a/server/src/test/java/org/opensearch/index/shard/PrimaryReplicaSyncerTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/PrimaryReplicaSyncerTests.java
@@ -37,21 +37,20 @@
 import org.opensearch.action.resync.ResyncReplicationResponse;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.index.seqno.SequenceNumbers;
@@ -94,7 +93,7 @@ public void testSyncerSendsOffCorrectDocuments() throws Exception {
             shard.applyIndexOperationOnPrimary(
                 Versions.MATCH_ANY,
                 VersionType.INTERNAL,
-                new SourceToParse(shard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), XContentType.JSON),
+                new SourceToParse(shard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), MediaTypeRegistry.JSON),
                 SequenceNumbers.UNASSIGNED_SEQ_NO,
                 0,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -176,7 +175,7 @@ public void testSyncerOnClosingShard() throws Exception {
             shard.applyIndexOperationOnPrimary(
                 Versions.MATCH_ANY,
                 VersionType.INTERNAL,
-                new SourceToParse(shard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), XContentType.JSON),
+                new SourceToParse(shard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), MediaTypeRegistry.JSON),
                 SequenceNumbers.UNASSIGNED_SEQ_NO,
                 0,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -315,7 +314,7 @@ public void testStatusReportsCorrectNumbers() throws IOException {
         PrimaryReplicaSyncer.ResyncTask.Status status = task.getStatus();
         XContentBuilder jsonBuilder = XContentFactory.jsonBuilder();
         status.toXContent(jsonBuilder, ToXContent.EMPTY_PARAMS);
-        String jsonString = Strings.toString(jsonBuilder);
+        String jsonString = jsonBuilder.toString();
         assertThat(jsonString, containsString("\"phase\":\"" + task.getPhase() + "\""));
         assertThat(jsonString, containsString("\"totalOperations\":" + task.getTotalOperations()));
         assertThat(jsonString, containsString("\"resyncedOperations\":" + task.getResyncedOperations()));
diff --git a/server/src/test/java/org/opensearch/index/shard/RefreshListenersTests.java b/server/src/test/java/org/opensearch/index/shard/RefreshListenersTests.java
index eea316d9a9370..87aa1f20c5991 100644
--- a/server/src/test/java/org/opensearch/index/shard/RefreshListenersTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/RefreshListenersTests.java
@@ -36,14 +36,13 @@
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.store.Directory;
 import org.opensearch.Version;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.metrics.MeanMetric;
@@ -51,9 +50,13 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.codec.CodecService;
 import org.opensearch.index.engine.Engine;
@@ -69,10 +72,9 @@
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.Scheduler.Cancellable;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -100,7 +102,7 @@
  */
 public class RefreshListenersTests extends OpenSearchTestCase {
     private RefreshListeners listeners;
-    private Engine engine;
+    private InternalEngine engine;
     private volatile int maxListeners;
     private ThreadPool threadPool;
     private Store store;
@@ -131,7 +133,8 @@ public void setupListeners() throws Exception {
             shardId,
             createTempDir("translog"),
             indexSettings,
-            BigArrays.NON_RECYCLING_INSTANCE
+            BigArrays.NON_RECYCLING_INSTANCE,
+            ""
         );
         Engine.EventListener eventListener = new Engine.EventListener() {
             @Override
@@ -148,33 +151,30 @@ public void onFailedEngine(String reason, @Nullable Exception e) {
             primaryTerm
         );
         store.associateIndexWithNewTranslog(translogUUID);
-        EngineConfig config = new EngineConfig(
-            shardId,
-            threadPool,
-            indexSettings,
-            null,
-            store,
-            newMergePolicy(),
-            iwc.getAnalyzer(),
-            iwc.getSimilarity(),
-            new CodecService(null, logger),
-            eventListener,
-            IndexSearcher.getDefaultQueryCache(),
-            IndexSearcher.getDefaultQueryCachingPolicy(),
-            translogConfig,
-            TimeValue.timeValueMinutes(5),
-            Collections.singletonList(listeners),
-            Collections.emptyList(),
-            null,
-            new NoneCircuitBreakerService(),
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            () -> RetentionLeases.EMPTY,
-            () -> primaryTerm,
-            EngineTestCase.tombstoneDocSupplier()
-        );
+        EngineConfig config = new EngineConfig.Builder().shardId(shardId)
+            .threadPool(threadPool)
+            .indexSettings(indexSettings)
+            .store(store)
+            .mergePolicy(newMergePolicy())
+            .analyzer(iwc.getAnalyzer())
+            .similarity(iwc.getSimilarity())
+            .codecService(new CodecService(null, indexSettings, logger))
+            .eventListener(eventListener)
+            .queryCache(IndexSearcher.getDefaultQueryCache())
+            .queryCachingPolicy(IndexSearcher.getDefaultQueryCachingPolicy())
+            .translogConfig(translogConfig)
+            .flushMergesAfter(TimeValue.timeValueMinutes(5))
+            .externalRefreshListener(Collections.singletonList(listeners))
+            .internalRefreshListener(Collections.emptyList())
+            .circuitBreakerService(new NoneCircuitBreakerService())
+            .globalCheckpointSupplier(() -> SequenceNumbers.NO_OPS_PERFORMED)
+            .retentionLeasesSupplier(() -> RetentionLeases.EMPTY)
+            .primaryTermSupplier(() -> primaryTerm)
+            .tombstoneDocSupplier(EngineTestCase.tombstoneDocSupplier())
+            .build();
         engine = new InternalEngine(config);
-        engine.recoverFromTranslog((e, s) -> 0, Long.MAX_VALUE);
-        listeners.setCurrentRefreshLocationSupplier(engine::getTranslogLastWriteLocation);
+        engine.translogManager().recoverFromTranslog((s) -> 0, engine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
+        listeners.setCurrentRefreshLocationSupplier(engine.translogManager()::getTranslogLastWriteLocation);
     }
 
     @After
@@ -371,9 +371,8 @@ public void testLotsOfThreads() throws Exception {
                         try (Engine.GetResult getResult = engine.get(get, engine::acquireSearcher)) {
                             assertTrue("document not found", getResult.exists());
                             assertEquals(iteration, getResult.version());
-                            org.apache.lucene.document.Document document = getResult.docIdAndVersion().reader.document(
-                                getResult.docIdAndVersion().docId
-                            );
+                            StoredFields storedFields = getResult.docIdAndVersion().reader.storedFields();
+                            org.apache.lucene.document.Document document = storedFields.document(getResult.docIdAndVersion().docId);
                             assertThat(document.getValues("test"), arrayContaining(testFieldValue));
                         }
                     } catch (Exception t) {
@@ -440,7 +439,16 @@ private Engine.IndexResult index(String id, String testFieldValue) throws IOExce
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
         BytesReference source = new BytesArray(new byte[] { 1 });
-        ParsedDocument doc = new ParsedDocument(versionField, seqID, id, null, Arrays.asList(document), source, XContentType.JSON, null);
+        ParsedDocument doc = new ParsedDocument(
+            versionField,
+            seqID,
+            id,
+            null,
+            Arrays.asList(document),
+            source,
+            MediaTypeRegistry.JSON,
+            null
+        );
         Engine.Index index = new Engine.Index(new Term("_id", doc.id()), engine.config().getPrimaryTermSupplier().getAsLong(), doc);
         return engine.index(index);
     }
diff --git a/server/src/test/java/org/opensearch/index/shard/RemoteIndexShardTests.java b/server/src/test/java/org/opensearch/index/shard/RemoteIndexShardTests.java
new file mode 100644
index 0000000000000..6a99063d11353
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/RemoteIndexShardTests.java
@@ -0,0 +1,479 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.lucene.index.IndexFileNames;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.util.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.engine.DocIdSeqNoAndSource;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.InternalEngine;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.CheckpointInfoResponse;
+import org.opensearch.indices.replication.GetSegmentFilesResponse;
+import org.opensearch.indices.replication.RemoteStoreReplicationSource;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.hamcrest.MatcherAssert;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
+
+import static org.opensearch.index.engine.EngineTestCase.assertAtMostOneLuceneDocumentPerSequenceNumber;
+import static org.opensearch.index.shard.RemoteStoreRefreshListener.EXCLUDE_FILES;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class RemoteIndexShardTests extends SegmentReplicationIndexShardTests {
+
+    private static final String REPOSITORY_NAME = "temp-fs";
+    private static final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+        .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, REPOSITORY_NAME)
+        .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, REPOSITORY_NAME)
+        .build();
+
+    protected Settings getIndexSettings() {
+        return settings;
+    }
+
+    protected ReplicationGroup getReplicationGroup(int numberOfReplicas) throws IOException {
+        return createGroup(numberOfReplicas, settings, indexMapping, new NRTReplicationEngineFactory(), createTempDir());
+    }
+
+    public void testNRTReplicaWithRemoteStorePromotedAsPrimaryRefreshRefresh() throws Exception {
+        testNRTReplicaWithRemoteStorePromotedAsPrimary(false, false);
+    }
+
+    public void testNRTReplicaWithRemoteStorePromotedAsPrimaryRefreshCommit() throws Exception {
+        testNRTReplicaWithRemoteStorePromotedAsPrimary(false, true);
+    }
+
+    public void testNRTReplicaWithRemoteStorePromotedAsPrimaryCommitRefresh() throws Exception {
+        testNRTReplicaWithRemoteStorePromotedAsPrimary(true, false);
+    }
+
+    public void testNRTReplicaWithRemoteStorePromotedAsPrimaryCommitCommit() throws Exception {
+        testNRTReplicaWithRemoteStorePromotedAsPrimary(true, true);
+    }
+
+    public void testNRTReplicaWithRemoteStorePromotedAsPrimary(boolean performFlushFirst, boolean performFlushSecond) throws Exception {
+        try (
+            ReplicationGroup shards = createGroup(1, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory(), createTempDir())
+        ) {
+            shards.startAll();
+            IndexShard oldPrimary = shards.getPrimary();
+            final IndexShard nextPrimary = shards.getReplicas().get(0);
+
+            // 1. Create ops that are in the index and xlog of both shards but not yet part of a commit point.
+            final int numDocs = shards.indexDocs(randomInt(10));
+
+            // refresh but do not copy the segments over.
+            if (performFlushFirst) {
+                flushShard(oldPrimary, true);
+            } else {
+                oldPrimary.refresh("Test");
+            }
+            // replicateSegments(primary, shards.getReplicas());
+
+            // at this point both shards should have numDocs persisted and searchable.
+            assertDocCounts(oldPrimary, numDocs, numDocs);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertDocCounts(shard, numDocs, 0);
+            }
+
+            // 2. Create ops that are in the replica's xlog, not in the index.
+            // index some more into both but don't replicate. replica will have only numDocs searchable, but should have totalDocs
+            // persisted.
+            final int additonalDocs = shards.indexDocs(randomInt(10));
+            final int totalDocs = numDocs + additonalDocs;
+
+            if (performFlushSecond) {
+                flushShard(oldPrimary, true);
+            } else {
+                oldPrimary.refresh("Test");
+            }
+            assertDocCounts(oldPrimary, totalDocs, totalDocs);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertDocCounts(shard, totalDocs, 0);
+            }
+            assertTrue(nextPrimary.translogStats().estimatedNumberOfOperations() >= additonalDocs);
+            assertTrue(nextPrimary.translogStats().getUncommittedOperations() >= additonalDocs);
+
+            int prevOperationCount = nextPrimary.translogStats().estimatedNumberOfOperations();
+
+            // promote the replica
+            shards.promoteReplicaToPrimary(nextPrimary).get();
+
+            // close oldPrimary.
+            oldPrimary.close("demoted", false, false);
+            oldPrimary.store().close();
+
+            assertEquals(InternalEngine.class, nextPrimary.getEngine().getClass());
+            assertDocCounts(nextPrimary, totalDocs, totalDocs);
+
+            // refresh and push segments to our other replica.
+            nextPrimary.refresh("test");
+
+            for (IndexShard shard : shards) {
+                assertConsistentHistoryBetweenTranslogAndLucene(shard);
+            }
+            final List<DocIdSeqNoAndSource> docsAfterRecovery = getDocIdAndSeqNos(shards.getPrimary());
+            for (IndexShard shard : shards.getReplicas()) {
+                assertThat(shard.routingEntry().toString(), getDocIdAndSeqNos(shard), equalTo(docsAfterRecovery));
+            }
+        }
+    }
+
+    public void testNoDuplicateSeqNo() throws Exception {
+        Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        ReplicationGroup shards = createGroup(1, settings, indexMapping, new NRTReplicationEngineFactory(), createTempDir());
+        final IndexShard primaryShard = shards.getPrimary();
+        final IndexShard replicaShard = shards.getReplicas().get(0);
+        shards.startPrimary();
+        shards.startAll();
+        shards.indexDocs(10);
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        flushShard(primaryShard);
+        shards.indexDocs(10);
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        shards.indexDocs(10);
+        primaryShard.refresh("test");
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        CountDownLatch latch = new CountDownLatch(1);
+        shards.promoteReplicaToPrimary(replicaShard, (shard, listener) -> {
+            try {
+                assertAtMostOneLuceneDocumentPerSequenceNumber(replicaShard.getEngine());
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+            latch.countDown();
+        });
+        latch.await();
+        for (IndexShard shard : shards) {
+            if (shard != null) {
+                closeShard(shard, false);
+            }
+        }
+    }
+
+    public void testReplicaCommitsInfosBytesOnRecovery() throws Exception {
+        final Path remotePath = createTempDir();
+        try (ReplicationGroup shards = createGroup(0, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory(), remotePath)) {
+            shards.startAll();
+            // ensure primary has uploaded something
+            shards.indexDocs(10);
+            shards.refresh("test");
+
+            final IndexShard primary = shards.getPrimary();
+            final Engine primaryEngine = getEngine(primary);
+            assertNotNull(primaryEngine);
+            final SegmentInfos latestCommit = SegmentInfos.readLatestCommit(primary.store().directory());
+            assertEquals("On-disk commit references no segments", Set.of("segments_3"), latestCommit.files(true));
+            assertEquals(
+                "Latest remote commit On-disk commit references no segments",
+                Set.of("segments_3"),
+                primary.remoteStore().readLastCommittedSegmentsInfo().files(true)
+            );
+
+            try (final GatedCloseable<SegmentInfos> segmentInfosSnapshot = primaryEngine.getSegmentInfosSnapshot()) {
+                MatcherAssert.assertThat(
+                    "Segments are referenced in memory only",
+                    segmentInfosSnapshot.get().files(false),
+                    containsInAnyOrder("_0.cfe", "_0.si", "_0.cfs")
+                );
+            }
+
+            final IndexShard replica = shards.addReplica(remotePath);
+            replica.store().createEmpty(Version.LATEST);
+            assertEquals(
+                "Replica starts at empty segment 2",
+                Set.of("segments_1"),
+                replica.store().readLastCommittedSegmentsInfo().files(true)
+            );
+            // commit replica infos so it has a conflicting commit with remote.
+            final SegmentInfos segmentCommitInfos = replica.store().readLastCommittedSegmentsInfo();
+            segmentCommitInfos.commit(replica.store().directory());
+            segmentCommitInfos.commit(replica.store().directory());
+            assertEquals(
+                "Replica starts recovery at empty segment 3",
+                Set.of("segments_3"),
+                replica.store().readLastCommittedSegmentsInfo().files(true)
+            );
+
+            shards.recoverReplica(replica);
+
+            final Engine replicaEngine = getEngine(replica);
+            assertNotNull(replicaEngine);
+            final SegmentInfos latestReplicaCommit = SegmentInfos.readLatestCommit(replica.store().directory());
+            logger.info(List.of(replica.store().directory().listAll()));
+            MatcherAssert.assertThat(
+                "Replica commits infos bytes referencing latest refresh point",
+                latestReplicaCommit.files(true),
+                containsInAnyOrder("_0.cfe", "_0.si", "_0.cfs", "segments_6")
+            );
+
+            try (final GatedCloseable<SegmentInfos> segmentInfosSnapshot = replicaEngine.getSegmentInfosSnapshot()) {
+                MatcherAssert.assertThat(
+                    "Segments are referenced in memory",
+                    segmentInfosSnapshot.get().files(false),
+                    containsInAnyOrder("_0.cfe", "_0.si", "_0.cfs")
+                );
+            }
+
+            final Store.RecoveryDiff recoveryDiff = Store.segmentReplicationDiff(
+                primary.getSegmentMetadataMap(),
+                replica.getSegmentMetadataMap()
+            );
+            assertTrue(recoveryDiff.missing.isEmpty());
+            assertTrue(recoveryDiff.different.isEmpty());
+        }
+    }
+
+    public void testPrimaryRestart_PrimaryHasExtraCommits() throws Exception {
+        final Path remotePath = createTempDir();
+        try (ReplicationGroup shards = createGroup(0, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory(), remotePath)) {
+            shards.startAll();
+            // ensure primary has uploaded something
+            shards.indexDocs(10);
+            IndexShard primary = shards.getPrimary();
+            if (randomBoolean()) {
+                flushShard(primary);
+            } else {
+                primary.refresh("test");
+            }
+            assertDocCount(primary, 10);
+            // get a metadata map - we'll use segrep diff to ensure segments on reader are identical after restart.
+            final Map<String, StoreFileMetadata> metadataBeforeRestart = primary.getSegmentMetadataMap();
+            // restart the primary
+            shards.reinitPrimaryShard(remotePath);
+            // the store is open at this point but the shard has not yet run through recovery
+            primary = shards.getPrimary();
+            SegmentInfos latestPrimaryCommit = SegmentInfos.readLatestCommit(primary.store().directory());
+            latestPrimaryCommit.commit(primary.store().directory());
+            latestPrimaryCommit = SegmentInfos.readLatestCommit(primary.store().directory());
+            latestPrimaryCommit.commit(primary.store().directory());
+            shards.startPrimary();
+            assertDocCount(primary, 10);
+            final Store.RecoveryDiff diff = Store.segmentReplicationDiff(metadataBeforeRestart, primary.getSegmentMetadataMap());
+            assertTrue(diff.missing.isEmpty());
+            assertTrue(diff.different.isEmpty());
+        }
+    }
+
+    public void testRepicaCleansUpOldCommitsWhenReceivingNew() throws Exception {
+        final Path remotePath = createTempDir();
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory(), remotePath)) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+            shards.indexDocs(1);
+            flushShard(primary);
+            replicateSegments(primary, shards.getReplicas());
+            assertDocCount(primary, 1);
+            assertDocCount(replica, 1);
+            assertEquals("segments_5", replica.store().readLastCommittedSegmentsInfo().getSegmentsFileName());
+            assertSingleSegmentFile(replica, "segments_5");
+
+            shards.indexDocs(1);
+            primary.refresh("test");
+            replicateSegments(primary, shards.getReplicas());
+            assertDocCount(replica, 2);
+            assertSingleSegmentFile(replica, "segments_5");
+
+            shards.indexDocs(1);
+            flushShard(primary);
+            replicateSegments(primary, shards.getReplicas());
+            assertDocCount(replica, 3);
+            assertSingleSegmentFile(replica, "segments_6");
+
+            final Store.RecoveryDiff diff = Store.segmentReplicationDiff(primary.getSegmentMetadataMap(), replica.getSegmentMetadataMap());
+            assertTrue(diff.missing.isEmpty());
+            assertTrue(diff.different.isEmpty());
+        }
+    }
+
+    public void testPrimaryRestart() throws Exception {
+        final Path remotePath = createTempDir();
+        try (ReplicationGroup shards = createGroup(0, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory(), remotePath)) {
+            shards.startAll();
+            // ensure primary has uploaded something
+            shards.indexDocs(10);
+            IndexShard primary = shards.getPrimary();
+            if (randomBoolean()) {
+                flushShard(primary);
+            } else {
+                primary.refresh("test");
+            }
+            assertDocCount(primary, 10);
+            // get a metadata map - we'll use segrep diff to ensure segments on reader are identical after restart.
+            final Map<String, StoreFileMetadata> metadataBeforeRestart = primary.getSegmentMetadataMap();
+            // restart the primary
+            shards.reinitPrimaryShard(remotePath);
+            // the store is open at this point but the shard has not yet run through recovery
+            primary = shards.getPrimary();
+            shards.startPrimary();
+            assertDocCount(primary, 10);
+            final Store.RecoveryDiff diff = Store.segmentReplicationDiff(metadataBeforeRestart, primary.getSegmentMetadataMap());
+            assertTrue(diff.missing.isEmpty());
+            logger.info("DIFF FILE {}", diff.different);
+            assertTrue(diff.different.isEmpty());
+        }
+    }
+
+    /**
+     * This test validates that unreferenced on disk file are ignored while requesting files from replication source to
+     * prevent FileAlreadyExistsException. It does so by only copying files in first round of segment replication without
+     * committing locally so that in next round of segment replication those files are not considered for download again
+     */
+    public void testSegRepSucceedsOnPreviousCopiedFiles() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            shards.indexDocs(10);
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            Runnable[] runAfterGetFiles = { () -> { throw new RuntimeException("Simulated"); }, () -> {} };
+            AtomicInteger index = new AtomicInteger(0);
+            RemoteStoreReplicationSource testRSReplicationSource = new RemoteStoreReplicationSource(replica) {
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    super.getCheckpointMetadata(replicationId, checkpoint, listener);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    super.getSegmentFiles(replicationId, checkpoint, filesToFetch, indexShard, listener);
+                    runAfterGetFiles[index.getAndIncrement()].run();
+                }
+
+                @Override
+                public String getDescription() {
+                    return "TestRemoteStoreReplicationSource";
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(testRSReplicationSource);
+            CountDownLatch latch = new CountDownLatch(1);
+
+            // Start first round of segment replication. This should fail with simulated error but with replica having
+            // files in its local store but not in active reader.
+            final SegmentReplicationTarget target = targetService.startReplication(
+                replica,
+                primary.getLatestReplicationCheckpoint(),
+                new SegmentReplicationTargetService.SegmentReplicationListener() {
+                    @Override
+                    public void onReplicationDone(SegmentReplicationState state) {
+                        Assert.fail("Replication should fail with simulated error");
+                    }
+
+                    @Override
+                    public void onReplicationFailure(
+                        SegmentReplicationState state,
+                        ReplicationFailedException e,
+                        boolean sendShardFailure
+                    ) {
+                        assertFalse(sendShardFailure);
+                        logger.error("Replication error", e);
+                        latch.countDown();
+                    }
+                }
+            );
+            latch.await();
+            Set<String> onDiskFiles = new HashSet<>(Arrays.asList(replica.store().directory().listAll()));
+            onDiskFiles.removeIf(name -> EXCLUDE_FILES.contains(name) || name.startsWith(IndexFileNames.SEGMENTS));
+            List<String> activeFiles = replica.getSegmentMetadataMap()
+                .values()
+                .stream()
+                .map(metadata -> metadata.name())
+                .collect(Collectors.toList());
+            assertTrue("Files should not be committed", activeFiles.isEmpty());
+            assertEquals("Files should be copied to disk", false, onDiskFiles.isEmpty());
+            assertEquals(target.state().getStage(), SegmentReplicationState.Stage.GET_FILES);
+
+            // Start next round of segment replication
+            CountDownLatch waitForSecondRound = new CountDownLatch(1);
+            final SegmentReplicationTarget newTarget = targetService.startReplication(
+                replica,
+                primary.getLatestReplicationCheckpoint(),
+                new SegmentReplicationTargetService.SegmentReplicationListener() {
+                    @Override
+                    public void onReplicationDone(SegmentReplicationState state) {
+                        waitForSecondRound.countDown();
+                    }
+
+                    @Override
+                    public void onReplicationFailure(
+                        SegmentReplicationState state,
+                        ReplicationFailedException e,
+                        boolean sendShardFailure
+                    ) {
+                        logger.error("Replication error", e);
+                        Assert.fail("Replication should not fail");
+                        waitForSecondRound.countDown();
+                    }
+                }
+            );
+            waitForSecondRound.await();
+            assertEquals(newTarget.state().getStage(), SegmentReplicationState.Stage.DONE);
+            activeFiles = replica.getSegmentMetadataMap().values().stream().map(metadata -> metadata.name()).collect(Collectors.toList());
+            assertTrue("Replica should have consistent disk & reader", activeFiles.containsAll(onDiskFiles));
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    private void assertSingleSegmentFile(IndexShard shard, String fileName) throws IOException {
+        final Set<String> segmentsFileNames = Arrays.stream(shard.store().directory().listAll())
+            .filter(file -> file.startsWith(IndexFileNames.SEGMENTS))
+            .collect(Collectors.toSet());
+        assertEquals("Expected a single segment file", 1, segmentsFileNames.size());
+        assertEquals(segmentsFileNames.stream().findFirst().get(), fileName);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/RemoteStoreRefreshListenerTests.java b/server/src/test/java/org/opensearch/index/shard/RemoteStoreRefreshListenerTests.java
new file mode 100644
index 0000000000000..941f2f48e71af
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/RemoteStoreRefreshListenerTests.java
@@ -0,0 +1,590 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.lucene.index.IndexFileNames;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.tests.store.BaseDirectoryWrapper;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.remote.RemoteSegmentTransferTracker;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.store.RemoteDirectory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory.MetadataFilenameUtils;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManager;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
+import static org.opensearch.index.store.RemoteSegmentStoreDirectory.METADATA_FILES_TO_FETCH;
+import static org.opensearch.test.RemoteStoreTestUtils.createMetadataFileBytes;
+import static org.opensearch.test.RemoteStoreTestUtils.getDummyMetadata;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteStoreRefreshListenerTests extends IndexShardTestCase {
+    private IndexShard indexShard;
+    private ClusterService clusterService;
+    private RemoteStoreRefreshListener remoteStoreRefreshListener;
+    private RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory;
+
+    public void setup(boolean primary, int numberOfDocs) throws IOException {
+        indexShard = newStartedShard(
+            primary,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "temp-fs")
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "temp-fs")
+                .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .build(),
+            new InternalEngineFactory()
+        );
+
+        if (primary) {
+            indexDocs(1, numberOfDocs);
+            indexShard.refresh("test");
+        }
+
+        clusterService = new ClusterService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+        remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, Settings.EMPTY);
+        remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+        RemoteSegmentTransferTracker tracker = remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        remoteStoreRefreshListener = new RemoteStoreRefreshListener(indexShard, SegmentReplicationCheckpointPublisher.EMPTY, tracker);
+    }
+
+    private void indexDocs(int startDocId, int numberOfDocs) throws IOException {
+        for (int i = startDocId; i < startDocId + numberOfDocs; i++) {
+            indexDoc(indexShard, "_doc", Integer.toString(i));
+        }
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        Directory storeDirectory = ((FilterDirectory) ((FilterDirectory) indexShard.store().directory()).getDelegate()).getDelegate();
+        ((BaseDirectoryWrapper) storeDirectory).setCheckIndexOnClose(false);
+        closeShards(indexShard);
+        super.tearDown();
+    }
+
+    public void testRemoteDirectoryInitThrowsException() throws IOException {
+        // Methods used in the constructor of RemoteSegmentTrackerListener have been mocked to reproduce specific exceptions
+        // to test the failure modes possible during construction of RemoteSegmentTrackerListener object.
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        indexShard = newStartedShard(false, indexSettings, new NRTReplicationEngineFactory());
+
+        // Mocking the IndexShard methods and dependent classes.
+        ShardId shardId = new ShardId("index1", "_na_", 1);
+        IndexShard shard = mock(IndexShard.class);
+        Store store = mock(Store.class);
+        Directory directory = mock(Directory.class);
+        ShardRouting shardRouting = mock(ShardRouting.class);
+        when(shard.store()).thenReturn(store);
+        when(store.directory()).thenReturn(directory);
+        when(shard.shardId()).thenReturn(shardId);
+        when(shard.routingEntry()).thenReturn(shardRouting);
+        when(shardRouting.primary()).thenReturn(true);
+        when(shard.getThreadPool()).thenReturn(mock(ThreadPool.class));
+
+        // Mock the Store, Directory and RemoteSegmentStoreDirectory classes
+        Store remoteStore = mock(Store.class);
+        when(shard.remoteStore()).thenReturn(remoteStore);
+        RemoteDirectory remoteMetadataDirectory = mock(RemoteDirectory.class);
+        AtomicLong listFilesCounter = new AtomicLong();
+
+        // Below we are trying to get the IOException thrown in the constructor of the RemoteSegmentStoreDirectory.
+        doAnswer(invocation -> {
+            if (listFilesCounter.incrementAndGet() <= 1) {
+                return Collections.singletonList("dummy string");
+            }
+            throw new IOException();
+        }).when(remoteMetadataDirectory)
+            .listFilesByPrefixInLexicographicOrder(MetadataFilenameUtils.METADATA_PREFIX, METADATA_FILES_TO_FETCH);
+
+        SegmentInfos segmentInfos;
+        try (Store indexShardStore = indexShard.store()) {
+            segmentInfos = indexShardStore.readLastCommittedSegmentsInfo();
+        }
+
+        when(remoteMetadataDirectory.getBlobStream(any())).thenAnswer(
+            I -> createMetadataFileBytes(getDummyMetadata("_0", 1), indexShard.getLatestReplicationCheckpoint(), segmentInfos)
+        );
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory = new RemoteSegmentStoreDirectory(
+            mock(RemoteDirectory.class),
+            remoteMetadataDirectory,
+            mock(RemoteStoreLockManager.class),
+            mock(ThreadPool.class),
+            shardId,
+            DefaultRecoverySettings.INSTANCE
+        );
+        FilterDirectory remoteStoreFilterDirectory = new RemoteStoreRefreshListenerTests.TestFilterDirectory(
+            new RemoteStoreRefreshListenerTests.TestFilterDirectory(remoteSegmentStoreDirectory)
+        );
+        when(remoteStore.directory()).thenReturn(remoteStoreFilterDirectory);
+
+        // Since the thrown IOException is caught in the constructor, ctor should be invoked successfully.
+        new RemoteStoreRefreshListener(shard, SegmentReplicationCheckpointPublisher.EMPTY, mock(RemoteSegmentTransferTracker.class));
+
+        // Validate that the stream of metadata file of remoteMetadataDirectory has been opened only once and the
+        // listFilesByPrefixInLexicographicOrder has been called twice.
+        verify(remoteMetadataDirectory, times(1)).getBlobStream(any());
+        verify(remoteMetadataDirectory, times(2)).listFilesByPrefixInLexicographicOrder(
+            MetadataFilenameUtils.METADATA_PREFIX,
+            METADATA_FILES_TO_FETCH
+        );
+    }
+
+    public void testAfterRefresh() throws IOException {
+        setup(true, 3);
+        assertDocs(indexShard, "1", "2", "3");
+
+        try (Store remoteStore = indexShard.remoteStore()) {
+            RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+                (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) remoteStore.directory()).getDelegate()).getDelegate();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+
+            // This is to check if reading data from remote segment store works as well.
+            remoteSegmentStoreDirectory.init();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+        }
+    }
+
+    public void testAfterCommit() throws IOException {
+        setup(true, 3);
+        assertDocs(indexShard, "1", "2", "3");
+        flushShard(indexShard);
+
+        try (Store remoteStore = indexShard.remoteStore()) {
+            RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+                (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) remoteStore.directory()).getDelegate()).getDelegate();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+
+            // This is to check if reading data from remote segment store works as well.
+            remoteSegmentStoreDirectory.init();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+        }
+    }
+
+    public void testRefreshAfterCommit() throws IOException {
+        setup(true, 3);
+        assertDocs(indexShard, "1", "2", "3");
+        flushShard(indexShard);
+
+        indexDocs(4, 4);
+        indexShard.refresh("test");
+
+        indexDocs(8, 4);
+        indexShard.refresh("test");
+
+        try (Store remoteStore = indexShard.remoteStore()) {
+            RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+                (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) remoteStore.directory()).getDelegate()).getDelegate();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+
+            // This is to check if reading data from remote segment store works as well.
+            remoteSegmentStoreDirectory.init();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+        }
+    }
+
+    public void testAfterMultipleCommits() throws IOException {
+        setup(true, 3);
+        assertDocs(indexShard, "1", "2", "3");
+
+        for (int i = 0; i < RemoteStoreRefreshListener.LAST_N_METADATA_FILES_TO_KEEP + 3; i++) {
+            indexDocs(4 * (i + 1), 4);
+            flushShard(indexShard);
+        }
+
+        try (Store remoteStore = indexShard.remoteStore()) {
+            RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+                (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) remoteStore.directory()).getDelegate()).getDelegate();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+
+            // This is to check if reading data from remote segment store works as well.
+            remoteSegmentStoreDirectory.init();
+
+            verifyUploadedSegments(remoteSegmentStoreDirectory);
+        }
+    }
+
+    public void testReplica() throws IOException {
+        setup(false, 3);
+        remoteStoreRefreshListener.afterRefresh(true);
+
+        try (Store remoteStore = indexShard.remoteStore()) {
+            RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+                (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) remoteStore.directory()).getDelegate()).getDelegate();
+
+            assertEquals(0, remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().size());
+        }
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/9773")
+    public void testReplicaPromotion() throws IOException, InterruptedException {
+        setup(false, 3);
+        remoteStoreRefreshListener.afterRefresh(true);
+
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+            (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) indexShard.remoteStore().directory()).getDelegate())
+                .getDelegate();
+
+        assertEquals(0, remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().size());
+
+        final ShardRouting replicaRouting = indexShard.routingEntry();
+        promoteReplica(
+            indexShard,
+            Collections.singleton(replicaRouting.allocationId().getId()),
+            new IndexShardRoutingTable.Builder(replicaRouting.shardId()).addShard(replicaRouting).build()
+        );
+
+        // The following logic is referenced from IndexShardTests.testPrimaryFillsSeqNoGapsOnPromotion
+        // ToDo: Add wait logic as part of promoteReplica()
+        final CountDownLatch latch = new CountDownLatch(1);
+        indexShard.acquirePrimaryOperationPermit(new ActionListener<>() {
+            @Override
+            public void onResponse(Releasable releasable) {
+                releasable.close();
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throw new AssertionError(e);
+            }
+        }, ThreadPool.Names.GENERIC, "");
+
+        latch.await();
+
+        indexDocs(4, 4);
+        indexShard.refresh("test");
+        remoteStoreRefreshListener.afterRefresh(true);
+
+        verifyUploadedSegments(remoteSegmentStoreDirectory);
+
+        // This is to check if reading data from remote segment store works as well.
+        remoteSegmentStoreDirectory.init();
+
+        verifyUploadedSegments(remoteSegmentStoreDirectory);
+    }
+
+    public void testRefreshSuccessOnFirstAttempt() throws Exception {
+        // This is the case of isRetry=false, shouldRetry=false
+        // Succeed on 1st attempt
+        int succeedOnAttempt = 1;
+        // We spy on IndexShard.getReplicationTracker() to validate that we have tried running remote time as per the expectation.
+        CountDownLatch refreshCountLatch = new CountDownLatch(succeedOnAttempt);
+        // We spy on IndexShard.getEngine() to validate that we have successfully hit the terminal code for ascertaining successful upload.
+        // Value has been set as 3 as during a successful upload IndexShard.getEngine() is hit thrice and with mockito we are counting down
+        CountDownLatch successLatch = new CountDownLatch(3);
+        Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> tuple = mockIndexShardWithRetryAndScheduleRefresh(
+            succeedOnAttempt,
+            refreshCountLatch,
+            successLatch
+        );
+        assertBusy(() -> assertEquals(0, refreshCountLatch.getCount()));
+        assertBusy(() -> assertEquals(0, successLatch.getCount()));
+        RemoteStoreStatsTrackerFactory trackerFactory = tuple.v2();
+        RemoteSegmentTransferTracker segmentTracker = trackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        assertNoLagAndTotalUploadsFailed(segmentTracker, 0);
+    }
+
+    public void testRefreshSuccessOnSecondAttempt() throws Exception {
+        // This covers 2 cases - 1) isRetry=false, shouldRetry=true 2) isRetry=true, shouldRetry=false
+        // Succeed on 2nd attempt
+        int succeedOnAttempt = 2;
+        // We spy on IndexShard.getReplicationTracker() to validate that we have tried running remote time as per the expectation.
+        CountDownLatch refreshCountLatch = new CountDownLatch(succeedOnAttempt);
+        // We spy on IndexShard.getEngine() to validate that we have successfully hit the terminal code for ascertaining successful upload.
+        // Value has been set as 3 as during a successful upload IndexShard.getEngine() is hit thrice and with mockito we are counting down
+        CountDownLatch successLatch = new CountDownLatch(3);
+        Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> tuple = mockIndexShardWithRetryAndScheduleRefresh(
+            succeedOnAttempt,
+            refreshCountLatch,
+            successLatch
+        );
+        assertBusy(() -> assertEquals(0, refreshCountLatch.getCount()));
+        assertBusy(() -> assertEquals(0, successLatch.getCount()));
+        RemoteStoreStatsTrackerFactory trackerFactory = tuple.v2();
+        RemoteSegmentTransferTracker segmentTracker = trackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        assertNoLagAndTotalUploadsFailed(segmentTracker, 1);
+    }
+
+    /**
+     * Tests retry flow after snapshot and metadata files have been uploaded to remote store in the failed attempt.
+     * Snapshot and metadata files created in failed attempt should not break retry.
+     */
+    public void testRefreshSuccessAfterFailureInFirstAttemptAfterSnapshotAndMetadataUpload() throws Exception {
+        int succeedOnAttempt = 1;
+        int checkpointPublishSucceedOnAttempt = 2;
+        // We spy on IndexShard.getReplicationTracker() to validate that we have tried running remote time as per the expectation.
+        CountDownLatch refreshCountLatch = new CountDownLatch(succeedOnAttempt);
+        // We spy on IndexShard.getEngine() to validate that we have successfully hit the terminal code for ascertaining successful upload.
+        // Value has been set as 6 as during a successful upload IndexShard.getEngine() is hit thrice and here we are running the flow twice
+        CountDownLatch successLatch = new CountDownLatch(3);
+        CountDownLatch reachedCheckpointPublishLatch = new CountDownLatch(0);
+        mockIndexShardWithRetryAndScheduleRefresh(
+            succeedOnAttempt,
+            refreshCountLatch,
+            successLatch,
+            checkpointPublishSucceedOnAttempt,
+            reachedCheckpointPublishLatch
+        );
+        assertBusy(() -> assertEquals(0, refreshCountLatch.getCount()));
+        assertBusy(() -> assertEquals(0, successLatch.getCount()));
+        assertBusy(() -> assertEquals(0, reachedCheckpointPublishLatch.getCount()));
+    }
+
+    public void testRefreshSuccessOnThirdAttempt() throws Exception {
+        // This covers 3 cases - 1) isRetry=false, shouldRetry=true 2) isRetry=true, shouldRetry=false 3) isRetry=True, shouldRetry=true
+        // Succeed on 3rd attempt
+        int succeedOnAttempt = 3;
+        // We spy on IndexShard.getReplicationTracker() to validate that we have tried running remote time as per the expectation.
+        CountDownLatch refreshCountLatch = new CountDownLatch(succeedOnAttempt);
+        // We spy on IndexShard.getEngine() to validate that we have successfully hit the terminal code for ascertaining successful upload.
+        // Value has been set as 3 as during a successful upload IndexShard.getEngine() is hit thrice and with mockito we are counting down
+        CountDownLatch successLatch = new CountDownLatch(3);
+        Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> tuple = mockIndexShardWithRetryAndScheduleRefresh(
+            succeedOnAttempt,
+            refreshCountLatch,
+            successLatch
+        );
+        assertBusy(() -> assertEquals(0, refreshCountLatch.getCount()));
+        assertBusy(() -> assertEquals(0, successLatch.getCount()));
+        RemoteStoreStatsTrackerFactory trackerFactory = tuple.v2();
+        RemoteSegmentTransferTracker segmentTracker = trackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        assertNoLagAndTotalUploadsFailed(segmentTracker, 2);
+    }
+
+    private void assertNoLagAndTotalUploadsFailed(RemoteSegmentTransferTracker segmentTracker, long totalUploadsFailed) throws Exception {
+        assertBusy(() -> {
+            assertEquals(0, segmentTracker.getBytesLag());
+            assertEquals(0, segmentTracker.getRefreshSeqNoLag());
+            assertEquals(0, segmentTracker.getTimeMsLag());
+            assertEquals(totalUploadsFailed, segmentTracker.getTotalUploadsFailed());
+        });
+    }
+
+    public void testTrackerData() throws Exception {
+        Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> tuple = mockIndexShardWithRetryAndScheduleRefresh(1);
+        RemoteStoreRefreshListener listener = tuple.v1();
+        RemoteStoreStatsTrackerFactory trackerFactory = tuple.v2();
+        RemoteSegmentTransferTracker tracker = trackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        assertNoLag(tracker);
+        indexDocs(100, randomIntBetween(100, 200));
+        indexShard.refresh("test");
+        listener.afterRefresh(true);
+        assertBusy(() -> assertNoLag(tracker));
+    }
+
+    private void assertNoLag(RemoteSegmentTransferTracker tracker) {
+        assertEquals(0, tracker.getRefreshSeqNoLag());
+        assertEquals(0, tracker.getBytesLag());
+        assertEquals(0, tracker.getTimeMsLag());
+        assertEquals(0, tracker.getRejectionCount());
+        assertEquals(tracker.getUploadBytesStarted(), tracker.getUploadBytesSucceeded());
+        assertTrue(tracker.getUploadBytesStarted() > 0);
+        assertEquals(0, tracker.getUploadBytesFailed());
+        assertEquals(0, tracker.getInflightUploads());
+        assertEquals(tracker.getTotalUploadsStarted(), tracker.getTotalUploadsSucceeded());
+        assertTrue(tracker.getTotalUploadsStarted() > 0);
+        assertEquals(0, tracker.getTotalUploadsFailed());
+    }
+
+    private Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> mockIndexShardWithRetryAndScheduleRefresh(
+        int succeedOnAttempt
+    ) throws IOException {
+        return mockIndexShardWithRetryAndScheduleRefresh(succeedOnAttempt, null, null);
+    }
+
+    private Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> mockIndexShardWithRetryAndScheduleRefresh(
+        int succeedOnAttempt,
+        CountDownLatch refreshCountLatch,
+        CountDownLatch successLatch
+    ) throws IOException {
+        CountDownLatch noOpLatch = new CountDownLatch(0);
+        return mockIndexShardWithRetryAndScheduleRefresh(succeedOnAttempt, refreshCountLatch, successLatch, 1, noOpLatch);
+    }
+
+    private Tuple<RemoteStoreRefreshListener, RemoteStoreStatsTrackerFactory> mockIndexShardWithRetryAndScheduleRefresh(
+        int succeedOnAttempt,
+        CountDownLatch refreshCountLatch,
+        CountDownLatch successLatch,
+        int succeedCheckpointPublishOnAttempt,
+        CountDownLatch reachedCheckpointPublishLatch
+    ) throws IOException {
+        // Create index shard that we will be using to mock different methods in IndexShard for the unit test
+        indexShard = newStartedShard(
+            true,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "temp-fs")
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "temp-fs")
+                .put(SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .build(),
+            new InternalEngineFactory()
+        );
+
+        indexDocs(1, randomIntBetween(1, 100));
+
+        // Mock indexShard.store().directory()
+        IndexShard shard = mock(IndexShard.class);
+        Store store = mock(Store.class);
+        when(shard.store()).thenReturn(store);
+        when(store.directory()).thenReturn(indexShard.store().directory());
+
+        // Mock (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) indexShard.remoteStore().directory())
+        Store remoteStore = mock(Store.class);
+        when(shard.remoteStore()).thenReturn(remoteStore);
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory =
+            (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) indexShard.remoteStore().directory()).getDelegate())
+                .getDelegate();
+        FilterDirectory remoteStoreFilterDirectory = new TestFilterDirectory(new TestFilterDirectory(remoteSegmentStoreDirectory));
+        when(remoteStore.directory()).thenReturn(remoteStoreFilterDirectory);
+
+        // Mock indexShard.getOperationPrimaryTerm()
+        when(shard.getLatestReplicationCheckpoint()).thenReturn(indexShard.getLatestReplicationCheckpoint());
+
+        // Mock indexShard.routingEntry().primary()
+        when(shard.routingEntry()).thenReturn(indexShard.routingEntry());
+
+        // Mock threadpool
+        when(shard.getThreadPool()).thenReturn(threadPool);
+
+        // Mock indexShard.getReplicationTracker().isPrimaryMode()
+
+        doAnswer(invocation -> {
+            if (Objects.nonNull(refreshCountLatch)) {
+                refreshCountLatch.countDown();
+            }
+            return indexShard.getReplicationTracker();
+        }).when(shard).getReplicationTracker();
+
+        AtomicLong counter = new AtomicLong();
+        // Mock indexShard.getSegmentInfosSnapshot()
+        doAnswer(invocation -> {
+            if (counter.incrementAndGet() <= succeedOnAttempt) {
+                throw new RuntimeException("Inducing failure in upload");
+            }
+            return indexShard.getSegmentInfosSnapshot();
+        }).when(shard).getSegmentInfosSnapshot();
+
+        doAnswer((invocation -> {
+            if (counter.incrementAndGet() <= succeedOnAttempt) {
+                throw new RuntimeException("Inducing failure in upload");
+            }
+            return indexShard.getLatestSegmentInfosAndCheckpoint();
+        })).when(shard).getLatestSegmentInfosAndCheckpoint();
+
+        doAnswer(invocation -> {
+            if (Objects.nonNull(successLatch)) {
+                successLatch.countDown();
+            }
+            return indexShard.getEngine();
+        }).when(shard).getEngine();
+
+        SegmentReplicationCheckpointPublisher emptyCheckpointPublisher = spy(SegmentReplicationCheckpointPublisher.EMPTY);
+        AtomicLong checkpointPublisherCounter = new AtomicLong();
+        doAnswer(invocation -> {
+            if (checkpointPublisherCounter.incrementAndGet() <= succeedCheckpointPublishOnAttempt - 1) {
+                throw new RuntimeException("Inducing failure after snapshot info snapshot to test if snapshot info file is deleted");
+            }
+            if (Objects.nonNull(reachedCheckpointPublishLatch)) {
+                reachedCheckpointPublishLatch.countDown();
+            }
+            return null;
+        }).when(emptyCheckpointPublisher).publish(any(), any());
+
+        clusterService = new ClusterService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+        RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory = indexShard.getRemoteStoreStatsTrackerFactory();
+        when(shard.indexSettings()).thenReturn(indexShard.indexSettings());
+        when(shard.shardId()).thenReturn(indexShard.shardId());
+        RemoteSegmentTransferTracker tracker = remoteStoreStatsTrackerFactory.getRemoteSegmentTransferTracker(indexShard.shardId());
+        RemoteStoreRefreshListener refreshListener = new RemoteStoreRefreshListener(shard, emptyCheckpointPublisher, tracker);
+        refreshListener.afterRefresh(true);
+        return Tuple.tuple(refreshListener, remoteStoreStatsTrackerFactory);
+    }
+
+    public static class TestFilterDirectory extends FilterDirectory {
+
+        /**
+         * Sole constructor, typically called from sub-classes.
+         *
+         * @param in input directory
+         */
+        public TestFilterDirectory(Directory in) {
+            super(in);
+        }
+    }
+
+    private void verifyUploadedSegments(RemoteSegmentStoreDirectory remoteSegmentStoreDirectory) throws IOException {
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+        String segmentsNFilename = null;
+        try (GatedCloseable<SegmentInfos> segmentInfosGatedCloseable = indexShard.getSegmentInfosSnapshot()) {
+            SegmentInfos segmentInfos = segmentInfosGatedCloseable.get();
+            for (String file : segmentInfos.files(true)) {
+                if (!RemoteStoreRefreshListener.EXCLUDE_FILES.contains(file)) {
+                    assertTrue(uploadedSegments.containsKey(file));
+                }
+                if (file.startsWith(IndexFileNames.SEGMENTS)) {
+                    segmentsNFilename = file;
+                }
+            }
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandTests.java b/server/src/test/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandTests.java
index 9a2a0dd7e070c..20e263d297e45 100644
--- a/server/src/test/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/RemoveCorruptedShardDataCommandTests.java
@@ -52,12 +52,13 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.gateway.PersistedClusterStateService;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.engine.EngineConfigFactory;
 import org.opensearch.index.engine.EngineException;
 import org.opensearch.index.engine.InternalEngineFactory;
@@ -132,7 +133,7 @@ public void setup() throws IOException {
         final Settings settings = Settings.builder()
             .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
             .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
-            .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+            .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
             .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
             .put(IndexMetadata.SETTING_INDEX_UUID, shardId.getIndex().getUUID())
             .build();
@@ -174,7 +175,8 @@ public void setup() throws IOException {
                 new EngineConfigFactory(new IndexSettings(indexMetadata, settings)),
                 () -> {},
                 RetentionLeaseSyncer.EMPTY,
-                EMPTY_EVENT_LISTENER
+                EMPTY_EVENT_LISTENER,
+                null
             ),
             true
         );
@@ -550,7 +552,8 @@ private IndexShard reopenIndexShard(boolean corrupted) throws IOException {
             indexShard.getEngineConfigFactory(),
             indexShard.getGlobalCheckpointSyncer(),
             indexShard.getRetentionLeaseSyncer(),
-            EMPTY_EVENT_LISTENER
+            EMPTY_EVENT_LISTENER,
+            null
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/index/shard/ReplicaRecoveryWithRemoteTranslogOnPrimaryTests.java b/server/src/test/java/org/opensearch/index/shard/ReplicaRecoveryWithRemoteTranslogOnPrimaryTests.java
new file mode 100644
index 0000000000000..88cb976f2fafb
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/ReplicaRecoveryWithRemoteTranslogOnPrimaryTests.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.RecoverySource;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingState;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.DocIdSeqNoAndSource;
+import org.opensearch.index.engine.NRTReplicationEngine;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.WriteOnlyTranslogManager;
+import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
+
+public class ReplicaRecoveryWithRemoteTranslogOnPrimaryTests extends OpenSearchIndexLevelReplicationTestCase {
+
+    private static final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+        .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "translog-repo")
+        .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "100ms")
+        .build();
+
+    public void testStartSequenceForReplicaRecovery() throws Exception {
+        final Path remoteDir = createTempDir();
+        final String indexMapping = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": {} }";
+        try (ReplicationGroup shards = createGroup(0, settings, indexMapping, new NRTReplicationEngineFactory(), remoteDir)) {
+            shards.startPrimary();
+            final IndexShard primary = shards.getPrimary();
+            int numDocs = shards.indexDocs(randomIntBetween(10, 100));
+            shards.flush();
+
+            final IndexShard replica = shards.addReplica(remoteDir);
+            shards.startAll();
+
+            allowShardFailures();
+            replica.failShard("test", null);
+
+            final ShardRouting replicaRouting = replica.routingEntry();
+            final IndexMetadata newIndexMetadata = IndexMetadata.builder(replica.indexSettings().getIndexMetadata())
+                .primaryTerm(replicaRouting.shardId().id(), replica.getOperationPrimaryTerm() + 1)
+                .build();
+            closeShards(replica);
+            shards.removeReplica(replica);
+
+            int moreDocs = shards.indexDocs(randomIntBetween(20, 100));
+            shards.flush();
+            IndexShard newReplicaShard = newShard(
+                newShardRouting(
+                    replicaRouting.shardId(),
+                    replicaRouting.currentNodeId(),
+                    false,
+                    ShardRoutingState.INITIALIZING,
+                    RecoverySource.PeerRecoverySource.INSTANCE
+                ),
+                replica.shardPath(),
+                newIndexMetadata,
+                null,
+                null,
+                replica.getEngineFactory(),
+                replica.getEngineConfigFactory(),
+                replica.getGlobalCheckpointSyncer(),
+                replica.getRetentionLeaseSyncer(),
+                EMPTY_EVENT_LISTENER,
+                remoteDir
+            );
+            shards.addReplica(newReplicaShard);
+            AtomicBoolean assertDone = new AtomicBoolean(false);
+            shards.recoverReplica(newReplicaShard, (r, sourceNode) -> new RecoveryTarget(r, sourceNode, recoveryListener) {
+                @Override
+                public IndexShard indexShard() {
+                    IndexShard idxShard = super.indexShard();
+                    if (assertDone.compareAndSet(false, true)) {
+                        // verify the starting sequence number while recovering a failed shard which has a valid last commit
+                        long startingSeqNo = -1;
+                        try {
+                            startingSeqNo = Long.parseLong(
+                                idxShard.store().readLastCommittedSegmentsInfo().getUserData().get(SequenceNumbers.MAX_SEQ_NO)
+                            );
+                        } catch (IOException e) {
+                            Assert.fail();
+                        }
+                        assertEquals(numDocs - 1, startingSeqNo);
+                    }
+                    return idxShard;
+                }
+            });
+            shards.flush();
+            replicateSegments(primary, shards.getReplicas());
+            shards.assertAllEqual(numDocs + moreDocs);
+        }
+    }
+
+    public void testNoTranslogHistoryTransferred() throws Exception {
+        final Path remoteDir = createTempDir();
+        final String indexMapping = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": {} }";
+        try (ReplicationGroup shards = createGroup(0, settings, indexMapping, new NRTReplicationEngineFactory(), remoteDir)) {
+
+            // Step1 - Start primary, index docs, flush, index more docs, check translog in primary as expected
+            shards.startPrimary();
+            final IndexShard primary = shards.getPrimary();
+            int numDocs = shards.indexDocs(randomIntBetween(10, 100));
+            shards.flush();
+            List<DocIdSeqNoAndSource> docIdAndSeqNosAfterFlush = getDocIdAndSeqNos(primary);
+            int moreDocs = shards.indexDocs(randomIntBetween(20, 100));
+            assertEquals(numDocs + moreDocs, getTranslog(primary).totalOperations());
+
+            // Step 2 - Start replica, recovery happens, check docs recovered till last flush
+            final IndexShard replica = shards.addReplica(remoteDir);
+            shards.startAll();
+            assertEquals(docIdAndSeqNosAfterFlush, getDocIdAndSeqNos(replica));
+            assertDocCount(replica, numDocs);
+            assertEquals(NRTReplicationEngine.class, replica.getEngine().getClass());
+
+            // Step 3 - Check replica's translog has no operations
+            assertEquals(WriteOnlyTranslogManager.class, ((NRTReplicationEngine) replica.getEngine()).translogManager().getClass());
+            WriteOnlyTranslogManager replicaTranslogManager = (WriteOnlyTranslogManager) ((NRTReplicationEngine) replica.getEngine())
+                .translogManager();
+            assertEquals(0, replicaTranslogManager.getTranslog().totalOperations());
+
+            // Adding this for close to succeed
+            shards.flush();
+            replicateSegments(primary, shards.getReplicas());
+            shards.assertAllEqual(numDocs + moreDocs);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/SearchOperationListenerTests.java b/server/src/test/java/org/opensearch/index/shard/SearchOperationListenerTests.java
index 8d89cc2383aeb..98f86758ea2ca 100644
--- a/server/src/test/java/org/opensearch/index/shard/SearchOperationListenerTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/SearchOperationListenerTests.java
@@ -138,7 +138,9 @@ public void validateReaderContext(ReaderContext readerContext, TransportRequest
         SearchOperationListener throwingListener = (SearchOperationListener) Proxy.newProxyInstance(
             SearchOperationListener.class.getClassLoader(),
             new Class[] { SearchOperationListener.class },
-            (a, b, c) -> { throw new RuntimeException(); }
+            (a, b, c) -> {
+                throw new RuntimeException();
+            }
         );
         int throwingListeners = 0;
         final List<SearchOperationListener> indexingOperationListeners = new ArrayList<>(Arrays.asList(listener, listener));
diff --git a/server/src/test/java/org/opensearch/index/shard/SegmentReplicationIndexShardTests.java b/server/src/test/java/org/opensearch/index/shard/SegmentReplicationIndexShardTests.java
new file mode 100644
index 0000000000000..528402d48658a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/SegmentReplicationIndexShardTests.java
@@ -0,0 +1,1080 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.action.admin.indices.flush.FlushRequest;
+import org.opensearch.action.admin.indices.forcemerge.ForceMergeRequest;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.SnapshotsInProgress;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.IndexShardRoutingTable;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.cluster.routing.ShardRoutingHelper;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.index.engine.DocIdSeqNoAndSource;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngine;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.engine.ReadOnlyEngine;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.replication.TestReplicationSource;
+import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.translog.SnapshotMatchers;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.CheckpointInfoResponse;
+import org.opensearch.indices.replication.GetSegmentFilesResponse;
+import org.opensearch.indices.replication.SegmentReplicationSource;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.repositories.IndexId;
+import org.opensearch.snapshots.Snapshot;
+import org.opensearch.snapshots.SnapshotId;
+import org.opensearch.snapshots.SnapshotInfoTests;
+import org.opensearch.snapshots.SnapshotShardsService;
+import org.opensearch.test.VersionUtils;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Function;
+
+import static org.opensearch.index.engine.EngineTestCase.assertAtMostOneLuceneDocumentPerSequenceNumber;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.hasToString;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationIndexShardTests extends OpenSearchIndexLevelReplicationTestCase {
+
+    private static final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .build();
+
+    protected ReplicationGroup getReplicationGroup(int numberOfReplicas) throws IOException {
+        return createGroup(numberOfReplicas, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory());
+    }
+
+    protected ReplicationGroup getReplicationGroup(int numberOfReplicas, String indexMapping) throws IOException {
+        return createGroup(numberOfReplicas, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory());
+    }
+
+    protected Settings getIndexSettings() {
+        return settings;
+    }
+
+    /**
+     * Validates happy path of segment replication where primary index docs which are replicated to replica shards. Assertions
+     * made on doc count on both primary and replica.
+     */
+    public void testReplication() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory());) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+
+            // index and replicate segments to replica.
+            int numDocs = randomIntBetween(10, 20);
+            shards.indexDocs(numDocs);
+            primaryShard.refresh("test");
+            flushShard(primaryShard);
+            replicateSegments(primaryShard, List.of(replicaShard));
+
+            // Assertions
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    /**
+     * Test that latestReplicationCheckpoint returns null only for docrep enabled indices
+     */
+    public void testReplicationCheckpointNullForDocRep() throws IOException {
+        Settings indexSettings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, "DOCUMENT").put(Settings.EMPTY).build();
+        final IndexShard indexShard = newStartedShard(false, indexSettings);
+        assertNull(indexShard.getLatestReplicationCheckpoint());
+        closeShards(indexShard);
+    }
+
+    /**
+     * Test that latestReplicationCheckpoint returns ReplicationCheckpoint for segrep enabled indices
+     */
+    public void testReplicationCheckpointNotNullForSegRep() throws IOException {
+        final IndexShard indexShard = newStartedShard(randomBoolean(), getIndexSettings(), new NRTReplicationEngineFactory());
+        final ReplicationCheckpoint replicationCheckpoint = indexShard.getLatestReplicationCheckpoint();
+        assertNotNull(replicationCheckpoint);
+        closeShards(indexShard);
+    }
+
+    public void testNRTReplicasDoNotAcceptRefreshListeners() throws IOException {
+        final IndexShard indexShard = newStartedShard(false, settings, new NRTReplicationEngineFactory());
+        indexShard.addRefreshListener(mock(Translog.Location.class), Assert::assertFalse);
+        closeShards(indexShard);
+    }
+
+    public void testSegmentInfosAndReplicationCheckpointTuple() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), indexMapping, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            // assert before any indexing:
+            // replica:
+            Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> replicaTuple = replica.getLatestSegmentInfosAndCheckpoint();
+            try (final GatedCloseable<SegmentInfos> gatedCloseable = replicaTuple.v1()) {
+                assertReplicationCheckpoint(replica, gatedCloseable.get(), replicaTuple.v2());
+            }
+
+            // primary:
+            Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> primaryTuple = primary.getLatestSegmentInfosAndCheckpoint();
+            try (final GatedCloseable<SegmentInfos> gatedCloseable = primaryTuple.v1()) {
+                assertReplicationCheckpoint(primary, gatedCloseable.get(), primaryTuple.v2());
+            }
+            // We use compareTo here instead of equals because we ignore segments gen with replicas performing their own commits.
+            // However infos version we expect to be equal.
+            assertEquals(1, primary.getLatestReplicationCheckpoint().compareTo(replica.getLatestReplicationCheckpoint()));
+
+            // index and copy segments to replica.
+            int numDocs = randomIntBetween(10, 20);
+            shards.indexDocs(numDocs);
+            primary.refresh("test");
+            replicateSegments(primary, List.of(replica));
+
+            replicaTuple = replica.getLatestSegmentInfosAndCheckpoint();
+            try (final GatedCloseable<SegmentInfos> gatedCloseable = replicaTuple.v1()) {
+                assertReplicationCheckpoint(replica, gatedCloseable.get(), replicaTuple.v2());
+            }
+
+            primaryTuple = primary.getLatestSegmentInfosAndCheckpoint();
+            try (final GatedCloseable<SegmentInfos> gatedCloseable = primaryTuple.v1()) {
+                assertReplicationCheckpoint(primary, gatedCloseable.get(), primaryTuple.v2());
+            }
+
+            replicaTuple = replica.getLatestSegmentInfosAndCheckpoint();
+            try (final GatedCloseable<SegmentInfos> gatedCloseable = replicaTuple.v1()) {
+                assertReplicationCheckpoint(replica, gatedCloseable.get(), replicaTuple.v2());
+            }
+            assertEquals(1, primary.getLatestReplicationCheckpoint().compareTo(replica.getLatestReplicationCheckpoint()));
+        }
+    }
+
+    public void testPrimaryRelocationWithSegRepFailure() throws Exception {
+        final IndexShard primarySource = newStartedShard(true, getIndexSettings());
+        int totalOps = randomInt(10);
+        for (int i = 0; i < totalOps; i++) {
+            indexDoc(primarySource, "_doc", Integer.toString(i));
+        }
+        IndexShardTestCase.updateRoutingEntry(primarySource, primarySource.routingEntry().relocate(randomAlphaOfLength(10), -1));
+        final IndexShard primaryTarget = newShard(
+            primarySource.routingEntry().getTargetRelocatingShard(),
+            getIndexSettings(),
+            new NRTReplicationEngineFactory()
+        );
+        updateMappings(primaryTarget, primarySource.indexSettings().getIndexMetadata());
+
+        Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction = (shardList) -> {
+            try {
+                throw new IOException("Expected failure");
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        };
+        Exception e = expectThrows(
+            Exception.class,
+            () -> recoverReplica(
+                primaryTarget,
+                primarySource,
+                (primary, sourceNode) -> new RecoveryTarget(primary, sourceNode, new ReplicationListener() {
+                    @Override
+                    public void onDone(ReplicationState state) {
+                        throw new AssertionError("recovery must fail");
+                    }
+
+                    @Override
+                    public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                        assertEquals(ExceptionsHelper.unwrap(e, IOException.class).getMessage(), "Expected failure");
+                    }
+                }),
+                true,
+                true,
+                replicatePrimaryFunction
+            )
+        );
+        closeShards(primarySource, primaryTarget);
+    }
+
+    private void assertReplicationCheckpoint(IndexShard shard, SegmentInfos segmentInfos, ReplicationCheckpoint checkpoint)
+        throws IOException {
+        assertNotNull(segmentInfos);
+        assertEquals(checkpoint.getSegmentInfosVersion(), segmentInfos.getVersion());
+        assertEquals(checkpoint.getSegmentsGen(), segmentInfos.getGeneration());
+    }
+
+    public void testIsSegmentReplicationAllowed_WrongEngineType() throws IOException {
+        final IndexShard indexShard = newShard(false, getIndexSettings(), new InternalEngineFactory());
+        assertFalse(indexShard.isSegmentReplicationAllowed());
+        closeShards(indexShard);
+    }
+
+    /**
+     * This test mimics the segment replication failure due to CorruptIndexException exception which happens when
+     * reader close operation on replica shard deletes the segment files copied in current round of segment replication.
+     * It does this by blocking the finalizeReplication on replica shard and performing close operation on acquired
+     * searcher that triggers the reader close operation.
+     */
+    public void testSegmentReplication_With_ReaderClosedConcurrently() throws Exception {
+        String mappings = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": { \"properties\": { \"foo\": { \"type\": \"keyword\"} }}}";
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), mappings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+
+            // Step 1. Ingest numDocs documents & replicate to replica shard
+            final int numDocs = randomIntBetween(10, 20);
+            logger.info("--> Inserting documents {}", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.refresh("Test");
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+            replicateSegments(primaryShard, shards.getReplicas());
+
+            IndexShard spyShard = spy(replicaShard);
+            Engine.Searcher test = replicaShard.getEngine().acquireSearcher("testSegmentReplication_With_ReaderClosedConcurrently");
+            shards.assertAllEqual(numDocs);
+
+            // Step 2. Ingest numDocs documents again & replicate to replica shard
+            logger.info("--> Ingest {} docs again", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+            replicateSegments(primaryShard, shards.getReplicas());
+
+            // Step 3. Perform force merge down to 1 segment on primary
+            primaryShard.forceMerge(new ForceMergeRequest().maxNumSegments(1).flush(true));
+            logger.info("--> primary store after force merge {}", Arrays.toString(primaryShard.store().directory().listAll()));
+            // Perform close on searcher before IndexShard::finalizeReplication
+            doAnswer(n -> {
+                test.close();
+                n.callRealMethod();
+                return null;
+            }).when(spyShard).finalizeReplication(any());
+            replicateSegments(primaryShard, List.of(spyShard));
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    /**
+     * Similar to test above, this test shows the issue where an engine close operation during active segment replication
+     * can result in Lucene CorruptIndexException.
+     */
+    public void testSegmentReplication_With_EngineClosedConcurrently() throws Exception {
+        String mappings = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": { \"properties\": { \"foo\": { \"type\": \"keyword\"} }}}";
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), mappings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+
+            // Step 1. Ingest numDocs documents
+            final int numDocs = randomIntBetween(10, 20);
+            logger.info("--> Inserting documents {}", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.refresh("Test");
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+            replicateSegments(primaryShard, shards.getReplicas());
+            shards.assertAllEqual(numDocs);
+
+            // Step 2. Ingest numDocs documents again to create a new commit
+            logger.info("--> Ingest {} docs again", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+            logger.info("--> primary store after final flush {}", Arrays.toString(primaryShard.store().directory().listAll()));
+
+            // Step 3. Before replicating segments, block finalizeReplication and perform engine commit directly that
+            // cleans up recently copied over files
+            IndexShard spyShard = spy(replicaShard);
+            doAnswer(n -> {
+                NRTReplicationEngine engine = (NRTReplicationEngine) replicaShard.getEngine();
+                // Using engine.close() prevents indexShard.finalizeReplication execution due to engine AlreadyClosedException,
+                // thus as workaround, use updateSegments which eventually calls commitSegmentInfos on latest segment infos.
+                engine.updateSegments(engine.getSegmentInfosSnapshot().get());
+                n.callRealMethod();
+                return null;
+            }).when(spyShard).finalizeReplication(any());
+            replicateSegments(primaryShard, List.of(spyShard));
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    public void testIgnoreShardIdle() throws Exception {
+        Settings updatedSettings = Settings.builder()
+            .put(getIndexSettings())
+            .put(IndexSettings.INDEX_SEARCH_IDLE_AFTER.getKey(), TimeValue.ZERO)
+            .build();
+        try (ReplicationGroup shards = createGroup(1, updatedSettings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+            final int numDocs = shards.indexDocs(randomIntBetween(1, 10));
+            // ensure search idle conditions are met.
+            assertTrue(primary.isSearchIdle());
+            assertTrue(replica.isSearchIdle());
+
+            // invoke scheduledRefresh, returns true if refresh is immediately invoked.
+            assertTrue(primary.scheduledRefresh());
+            // replica would always return false here as there is no indexed doc to refresh on.
+            assertFalse(replica.scheduledRefresh());
+
+            // assert there is no pending refresh
+            assertFalse(primary.hasRefreshPending());
+            assertFalse(replica.hasRefreshPending());
+            shards.refresh("test");
+            replicateSegments(primary, shards.getReplicas());
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    public void testShardIdle_Docrep() throws Exception {
+        Settings settings = Settings.builder()
+            .put(IndexSettings.INDEX_SEARCH_IDLE_AFTER.getKey(), TimeValue.ZERO)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+            .build();
+        try (ReplicationGroup shards = createGroup(1, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+            final int numDocs = shards.indexDocs(randomIntBetween(1, 10));
+            // ensure search idle conditions are met.
+            assertTrue(primary.isSearchIdle());
+            assertTrue(replica.isSearchIdle());
+            assertFalse(primary.scheduledRefresh());
+            assertFalse(replica.scheduledRefresh());
+            assertTrue(primary.hasRefreshPending());
+            assertTrue(replica.hasRefreshPending());
+            shards.refresh("test");
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    public void testShardIdleWithNoReplicas() throws Exception {
+        Settings updatedSettings = Settings.builder()
+            .put(getIndexSettings())
+            .put(IndexSettings.INDEX_SEARCH_IDLE_AFTER.getKey(), TimeValue.ZERO)
+            .build();
+        try (ReplicationGroup shards = createGroup(0, updatedSettings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            shards.indexDocs(randomIntBetween(1, 10));
+            // ensure search idle conditions are met.
+            assertTrue(primary.isSearchIdle());
+            assertFalse(primary.scheduledRefresh());
+            assertTrue(primary.hasRefreshPending());
+        }
+    }
+
+    /**
+     * here we are starting a new primary shard in PrimaryMode and testing if the shard publishes checkpoint after refresh.
+     */
+    public void testPublishCheckpointOnPrimaryMode() throws IOException, InterruptedException {
+        final SegmentReplicationCheckpointPublisher mock = mock(SegmentReplicationCheckpointPublisher.class);
+        IndexShard shard = newStartedShard(p -> newShard(false, mock, settings), false);
+
+        final ShardRouting shardRouting = shard.routingEntry();
+        promoteReplica(
+            shard,
+            Collections.singleton(shardRouting.allocationId().getId()),
+            new IndexShardRoutingTable.Builder(shardRouting.shardId()).addShard(shardRouting).build()
+        );
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        shard.acquirePrimaryOperationPermit(new ActionListener<Releasable>() {
+            @Override
+            public void onResponse(Releasable releasable) {
+                releasable.close();
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throw new RuntimeException(e);
+            }
+        }, ThreadPool.Names.GENERIC, "");
+
+        latch.await();
+        // verify checkpoint is published
+        verify(mock, times(1)).publish(any(), any());
+        closeShards(shard);
+    }
+
+    public void testPublishCheckpointOnPrimaryMode_segrep_off() throws IOException, InterruptedException {
+        final SegmentReplicationCheckpointPublisher mock = mock(SegmentReplicationCheckpointPublisher.class);
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+        IndexShard shard = newStartedShard(p -> newShard(false, mock, settings), false);
+
+        final ShardRouting shardRouting = shard.routingEntry();
+        promoteReplica(
+            shard,
+            Collections.singleton(shardRouting.allocationId().getId()),
+            new IndexShardRoutingTable.Builder(shardRouting.shardId()).addShard(shardRouting).build()
+        );
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        shard.acquirePrimaryOperationPermit(new ActionListener<Releasable>() {
+            @Override
+            public void onResponse(Releasable releasable) {
+                releasable.close();
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                throw new RuntimeException(e);
+            }
+        }, ThreadPool.Names.GENERIC, "");
+
+        latch.await();
+        // verify checkpoint is published
+        verify(mock, times(0)).publish(any(), any());
+        closeShards(shard);
+    }
+
+    public void testPublishCheckpointPostFailover() throws IOException {
+        final SegmentReplicationCheckpointPublisher mock = mock(SegmentReplicationCheckpointPublisher.class);
+        IndexShard shard = newStartedShard(true);
+        CheckpointRefreshListener refreshListener = new CheckpointRefreshListener(shard, mock);
+        refreshListener.afterRefresh(true);
+
+        // verify checkpoint is published
+        verify(mock, times(1)).publish(any(), any());
+        closeShards(shard);
+    }
+
+    /**
+     * here we are starting a new primary shard in PrimaryMode initially and starting relocation handoff. Later we complete relocation handoff then shard is no longer
+     * in PrimaryMode, and we test if the shard does not publish checkpoint after refresh.
+     */
+    public void testPublishCheckpointAfterRelocationHandOff() throws IOException {
+        final SegmentReplicationCheckpointPublisher mock = mock(SegmentReplicationCheckpointPublisher.class);
+        IndexShard shard = newStartedShard(true);
+        CheckpointRefreshListener refreshListener = new CheckpointRefreshListener(shard, mock);
+        String id = shard.routingEntry().allocationId().getId();
+
+        // Starting relocation handoff
+        shard.getReplicationTracker().startRelocationHandoff(id);
+
+        // Completing relocation handoff
+        shard.getReplicationTracker().completeRelocationHandoff();
+        refreshListener.afterRefresh(true);
+
+        // verify checkpoint is not published
+        verify(mock, times(0)).publish(any(), any());
+        closeShards(shard);
+    }
+
+    /**
+     * here we are starting a new primary shard and testing that we don't process a checkpoint on a shard when it's shard routing is primary.
+     */
+    public void testRejectCheckpointOnShardRoutingPrimary() throws IOException {
+        IndexShard primaryShard = newStartedShard(true);
+        SegmentReplicationTargetService sut;
+        sut = prepareForReplication(primaryShard, null);
+        SegmentReplicationTargetService spy = spy(sut);
+
+        // Starting a new shard in PrimaryMode and shard routing primary.
+        IndexShard spyShard = spy(primaryShard);
+        String id = primaryShard.routingEntry().allocationId().getId();
+
+        // Starting relocation handoff
+        primaryShard.getReplicationTracker().startRelocationHandoff(id);
+
+        // Completing relocation handoff.
+        primaryShard.getReplicationTracker().completeRelocationHandoff();
+
+        // Assert that primary shard is no longer in Primary Mode and shard routing is still Primary
+        assertEquals(false, primaryShard.getReplicationTracker().isPrimaryMode());
+        assertEquals(true, primaryShard.routingEntry().primary());
+
+        spy.onNewCheckpoint(new ReplicationCheckpoint(primaryShard.shardId(), 0L, 0L, 0L, Codec.getDefault().getName()), spyShard);
+
+        // Verify that checkpoint is not processed as shard routing is primary.
+        verify(spy, times(0)).startReplication(any(), any(), any());
+        closeShards(primaryShard);
+    }
+
+    // Todo: Remove this test when there is a better mechanism to test a functionality passing in different replication
+    // strategy.
+    public void testLockingBeforeAndAfterRelocated() throws Exception {
+        final IndexShard shard = newStartedShard(true, getIndexSettings());
+        final ShardRouting routing = ShardRoutingHelper.relocate(shard.routingEntry(), "other_node");
+        IndexShardTestCase.updateRoutingEntry(shard, routing);
+        CountDownLatch latch = new CountDownLatch(1);
+        Thread recoveryThread = new Thread(() -> {
+            latch.countDown();
+            try {
+                shard.relocated(routing.getTargetRelocatingShard().allocationId().getId(), primaryContext -> {}, () -> {});
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        try (Releasable ignored = acquirePrimaryOperationPermitBlockingly(shard)) {
+            // start finalization of recovery
+            recoveryThread.start();
+            latch.await();
+            // recovery can only be finalized after we release the current primaryOperationLock
+            assertFalse(shard.isRelocatedPrimary());
+        }
+        // recovery can be now finalized
+        recoveryThread.join();
+        assertTrue(shard.isRelocatedPrimary());
+        final ExecutionException e = expectThrows(ExecutionException.class, () -> acquirePrimaryOperationPermitBlockingly(shard));
+        assertThat(e.getCause(), instanceOf(ShardNotInPrimaryModeException.class));
+        assertThat(e.getCause(), hasToString(containsString("shard is not in primary mode")));
+
+        closeShards(shard);
+    }
+
+    // Todo: Remove this test when there is a better mechanism to test a functionality passing in different replication
+    // strategy.
+    public void testDelayedOperationsBeforeAndAfterRelocated() throws Exception {
+        final IndexShard shard = newStartedShard(true, getIndexSettings());
+        final ShardRouting routing = ShardRoutingHelper.relocate(shard.routingEntry(), "other_node");
+        IndexShardTestCase.updateRoutingEntry(shard, routing);
+        final CountDownLatch startRecovery = new CountDownLatch(1);
+        final CountDownLatch relocationStarted = new CountDownLatch(1);
+        Thread recoveryThread = new Thread(() -> {
+            try {
+                startRecovery.await();
+                shard.relocated(
+                    routing.getTargetRelocatingShard().allocationId().getId(),
+                    primaryContext -> relocationStarted.countDown(),
+                    () -> {}
+                );
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        });
+
+        recoveryThread.start();
+
+        final int numberOfAcquisitions = randomIntBetween(1, 10);
+        final List<Runnable> assertions = new ArrayList<>(numberOfAcquisitions);
+        final int recoveryIndex = randomIntBetween(0, numberOfAcquisitions - 1);
+
+        for (int i = 0; i < numberOfAcquisitions; i++) {
+            final PlainActionFuture<Releasable> onLockAcquired;
+            if (i < recoveryIndex) {
+                final AtomicBoolean invoked = new AtomicBoolean();
+                onLockAcquired = new PlainActionFuture<Releasable>() {
+
+                    @Override
+                    public void onResponse(Releasable releasable) {
+                        invoked.set(true);
+                        releasable.close();
+                        super.onResponse(releasable);
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        throw new AssertionError();
+                    }
+
+                };
+                assertions.add(() -> assertTrue(invoked.get()));
+            } else if (recoveryIndex == i) {
+                startRecovery.countDown();
+                relocationStarted.await();
+                onLockAcquired = new PlainActionFuture<>();
+                assertions.add(() -> {
+                    final ExecutionException e = expectThrows(ExecutionException.class, () -> onLockAcquired.get(30, TimeUnit.SECONDS));
+                    assertThat(e.getCause(), instanceOf(ShardNotInPrimaryModeException.class));
+                    assertThat(e.getCause(), hasToString(containsString("shard is not in primary mode")));
+                });
+            } else {
+                onLockAcquired = new PlainActionFuture<>();
+                assertions.add(() -> {
+                    final ExecutionException e = expectThrows(ExecutionException.class, () -> onLockAcquired.get(30, TimeUnit.SECONDS));
+                    assertThat(e.getCause(), instanceOf(ShardNotInPrimaryModeException.class));
+                    assertThat(e.getCause(), hasToString(containsString("shard is not in primary mode")));
+                });
+            }
+
+            shard.acquirePrimaryOperationPermit(onLockAcquired, ThreadPool.Names.WRITE, "i_" + i);
+        }
+
+        for (final Runnable assertion : assertions) {
+            assertion.run();
+        }
+
+        recoveryThread.join();
+
+        closeShards(shard);
+    }
+
+    public void testCloseShardDuringFinalize() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+            final IndexShard replicaSpy = spy(replica);
+
+            primary.refresh("Test");
+
+            doThrow(AlreadyClosedException.class).when(replicaSpy).finalizeReplication(any());
+
+            replicateSegments(primary, List.of(replicaSpy));
+        }
+    }
+
+    public void testBeforeIndexShardClosedWhileCopyingFiles() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+
+                ActionListener<GetSegmentFilesResponse> listener;
+
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    resolveCheckpointInfoResponseListener(listener, primary);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    // set the listener, we will only fail it once we cancel the source.
+                    this.listener = listener;
+                    // shard is closing while we are copying files.
+                    targetService.beforeIndexShardClosed(replica.shardId, replica, Settings.EMPTY);
+                }
+
+                @Override
+                public void cancel() {
+                    // simulate listener resolving, but only after we have issued a cancel from beforeIndexShardClosed .
+                    final RuntimeException exception = new CancellableThreads.ExecutionCancelledException("retryable action was cancelled");
+                    listener.onFailure(exception);
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(replica, primary, targetService);
+
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    protected SegmentReplicationTargetService newTargetService(SegmentReplicationSourceFactory sourceFactory) {
+        return new SegmentReplicationTargetService(
+            threadPool,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            mock(TransportService.class),
+            sourceFactory,
+            null,
+            null
+        );
+    }
+
+    public void testNoDuplicateSeqNo() throws Exception {
+        Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        ReplicationGroup shards = createGroup(1, settings, indexMapping, new NRTReplicationEngineFactory(), createTempDir());
+        final IndexShard primaryShard = shards.getPrimary();
+        final IndexShard replicaShard = shards.getReplicas().get(0);
+        shards.startPrimary();
+        shards.startAll();
+        shards.indexDocs(10);
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        flushShard(primaryShard);
+        shards.indexDocs(10);
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        shards.indexDocs(10);
+        primaryShard.refresh("test");
+        replicateSegments(primaryShard, shards.getReplicas());
+
+        CountDownLatch latch = new CountDownLatch(1);
+        shards.promoteReplicaToPrimary(replicaShard, (shard, listener) -> {
+            try {
+                assertAtMostOneLuceneDocumentPerSequenceNumber(replicaShard.getEngine());
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+            latch.countDown();
+        });
+        latch.await();
+        for (IndexShard shard : shards) {
+            if (shard != null) {
+                closeShard(shard, false);
+            }
+        }
+    }
+
+    public void testQueryDuringEngineResetShowsDocs() throws Exception {
+        final NRTReplicationEngineFactory engineFactory = new NRTReplicationEngineFactory();
+        final NRTReplicationEngineFactory spy = spy(engineFactory);
+        try (ReplicationGroup shards = createGroup(1, settings, indexMapping, spy, createTempDir())) {
+            final IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+            shards.startAll();
+            shards.indexDocs(10);
+            shards.refresh("test");
+            replicateSegments(primaryShard, shards.getReplicas());
+            shards.assertAllEqual(10);
+
+            final AtomicReference<Throwable> failed = new AtomicReference<>();
+            doAnswer(ans -> {
+                try {
+                    final Engine engineOrNull = replicaShard.getEngineOrNull();
+                    assertNotNull(engineOrNull);
+                    assertTrue(engineOrNull instanceof ReadOnlyEngine);
+                    shards.assertAllEqual(10);
+                } catch (Throwable e) {
+                    failed.set(e);
+                }
+                return ans.callRealMethod();
+            }).when(spy).newReadWriteEngine(any());
+            shards.promoteReplicaToPrimary(replicaShard).get();
+            assertNull("Expected correct doc count during engine reset", failed.get());
+        }
+    }
+
+    public void testSegmentReplicationStats() throws Exception {
+        final NRTReplicationEngineFactory engineFactory = new NRTReplicationEngineFactory();
+        final NRTReplicationEngineFactory spy = spy(engineFactory);
+        try (ReplicationGroup shards = createGroup(1, settings, indexMapping, spy, createTempDir())) {
+            final IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+            shards.startAll();
+
+            assertReplicaCaughtUp(primaryShard);
+
+            shards.indexDocs(10);
+            shards.refresh("test");
+
+            final ReplicationCheckpoint primaryCheckpoint = primaryShard.getLatestReplicationCheckpoint();
+            final long initialCheckpointSize = primaryCheckpoint.getMetadataMap()
+                .values()
+                .stream()
+                .mapToLong(StoreFileMetadata::length)
+                .sum();
+
+            Set<SegmentReplicationShardStats> postRefreshStats = primaryShard.getReplicationStatsForTrackedReplicas();
+            SegmentReplicationShardStats shardStats = postRefreshStats.stream().findFirst().get();
+            assertEquals(1, shardStats.getCheckpointsBehindCount());
+            assertEquals(initialCheckpointSize, shardStats.getBytesBehindCount());
+            replicateSegments(primaryShard, shards.getReplicas());
+            assertReplicaCaughtUp(primaryShard);
+            shards.assertAllEqual(10);
+
+            final List<DocIdSeqNoAndSource> docIdAndSeqNos = getDocIdAndSeqNos(primaryShard);
+            for (DocIdSeqNoAndSource docIdAndSeqNo : docIdAndSeqNos.subList(0, 5)) {
+                deleteDoc(primaryShard, docIdAndSeqNo.getId());
+                // delete on replica for xlog.
+                deleteDoc(replicaShard, docIdAndSeqNo.getId());
+            }
+            primaryShard.forceMerge(new ForceMergeRequest().maxNumSegments(1).flush(true));
+
+            final Map<String, StoreFileMetadata> segmentMetadataMap = primaryShard.getSegmentMetadataMap();
+            final Store.RecoveryDiff diff = Store.segmentReplicationDiff(segmentMetadataMap, replicaShard.getSegmentMetadataMap());
+            final long sizeAfterDeleteAndCommit = diff.missing.stream().mapToLong(StoreFileMetadata::length).sum();
+
+            final Set<SegmentReplicationShardStats> statsAfterFlush = primaryShard.getReplicationStatsForTrackedReplicas();
+            shardStats = statsAfterFlush.stream().findFirst().get();
+            assertEquals(sizeAfterDeleteAndCommit, shardStats.getBytesBehindCount());
+            assertEquals(1, shardStats.getCheckpointsBehindCount());
+
+            replicateSegments(primaryShard, shards.getReplicas());
+            assertReplicaCaughtUp(primaryShard);
+            shards.assertAllEqual(5);
+        }
+    }
+
+    public void testSnapshotWhileFailoverIncomplete() throws Exception {
+        final NRTReplicationEngineFactory engineFactory = new NRTReplicationEngineFactory();
+        final NRTReplicationEngineFactory spy = spy(engineFactory);
+        try (ReplicationGroup shards = createGroup(1, settings, indexMapping, spy, createTempDir())) {
+            final IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replicaShard = shards.getReplicas().get(0);
+            shards.startAll();
+            shards.indexDocs(10);
+            shards.refresh("test");
+            replicateSegments(primaryShard, shards.getReplicas());
+            shards.assertAllEqual(10);
+
+            final SnapshotShardsService shardsService = getSnapshotShardsService(replicaShard);
+            final Snapshot snapshot = new Snapshot(randomAlphaOfLength(10), new SnapshotId(randomAlphaOfLength(5), randomAlphaOfLength(5)));
+
+            final ClusterState initState = addSnapshotIndex(clusterService.state(), snapshot, replicaShard, SnapshotsInProgress.State.INIT);
+            shardsService.clusterChanged(new ClusterChangedEvent("test", initState, clusterService.state()));
+
+            CountDownLatch latch = new CountDownLatch(1);
+            doAnswer(ans -> {
+                final Engine engineOrNull = replicaShard.getEngineOrNull();
+                assertNotNull(engineOrNull);
+                assertTrue(engineOrNull instanceof ReadOnlyEngine);
+                shards.assertAllEqual(10);
+                shardsService.clusterChanged(
+                    new ClusterChangedEvent(
+                        "test",
+                        addSnapshotIndex(clusterService.state(), snapshot, replicaShard, SnapshotsInProgress.State.STARTED),
+                        initState
+                    )
+                );
+                latch.countDown();
+                return ans.callRealMethod();
+            }).when(spy).newReadWriteEngine(any());
+            shards.promoteReplicaToPrimary(replicaShard).get();
+            latch.await();
+            assertBusy(() -> {
+                final IndexShardSnapshotStatus.Copy copy = shardsService.currentSnapshotShards(snapshot).get(replicaShard.shardId).asCopy();
+                final IndexShardSnapshotStatus.Stage stage = copy.getStage();
+                assertEquals(IndexShardSnapshotStatus.Stage.FAILURE, stage);
+                assertNotNull(copy.getFailure());
+                assertTrue(
+                    copy.getFailure()
+                        .contains("snapshot triggered on a new primary following failover and cannot proceed until promotion is complete")
+                );
+            });
+        }
+    }
+
+    private SnapshotShardsService getSnapshotShardsService(IndexShard replicaShard) {
+        final TransportService transportService = mock(TransportService.class);
+        when(transportService.getThreadPool()).thenReturn(threadPool);
+        final IndicesService indicesService = mock(IndicesService.class);
+        final IndexService indexService = mock(IndexService.class);
+        when(indicesService.indexServiceSafe(any())).thenReturn(indexService);
+        when(indexService.getShardOrNull(anyInt())).thenReturn(replicaShard);
+        return new SnapshotShardsService(settings, clusterService, createRepositoriesService(), transportService, indicesService);
+    }
+
+    private ClusterState addSnapshotIndex(
+        ClusterState state,
+        Snapshot snapshot,
+        IndexShard shard,
+        SnapshotsInProgress.State snapshotState
+    ) {
+        final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardsBuilder = new HashMap<>();
+        ShardRouting shardRouting = shard.shardRouting;
+        shardsBuilder.put(
+            shardRouting.shardId(),
+            new SnapshotsInProgress.ShardSnapshotStatus(state.getNodes().getLocalNode().getId(), "1")
+        );
+        final SnapshotsInProgress.Entry entry = new SnapshotsInProgress.Entry(
+            snapshot,
+            randomBoolean(),
+            false,
+            snapshotState,
+            Collections.singletonList(new IndexId(index.getName(), index.getUUID())),
+            Collections.emptyList(),
+            randomNonNegativeLong(),
+            randomLong(),
+            shardsBuilder,
+            null,
+            SnapshotInfoTests.randomUserMetadata(),
+            VersionUtils.randomVersion(random()),
+            false
+        );
+        return ClusterState.builder(state)
+            .putCustom(SnapshotsInProgress.TYPE, SnapshotsInProgress.of(Collections.singletonList(entry)))
+            .build();
+    }
+
+    private void assertReplicaCaughtUp(IndexShard primaryShard) {
+        Set<SegmentReplicationShardStats> initialStats = primaryShard.getReplicationStatsForTrackedReplicas();
+        assertEquals(initialStats.size(), 1);
+        SegmentReplicationShardStats shardStats = initialStats.stream().findFirst().get();
+        assertEquals(0, shardStats.getCheckpointsBehindCount());
+        assertEquals(0, shardStats.getBytesBehindCount());
+    }
+
+    /**
+     * Assert persisted and searchable doc counts.  This method should not be used while docs are concurrently indexed because
+     * it asserts point in time seqNos are relative to the doc counts.
+     */
+    protected void assertDocCounts(IndexShard indexShard, int expectedPersistedDocCount, int expectedSearchableDocCount)
+        throws IOException {
+        assertDocCount(indexShard, expectedSearchableDocCount);
+        // assigned seqNos start at 0, so assert max & local seqNos are 1 less than our persisted doc count.
+        assertEquals(expectedPersistedDocCount - 1, indexShard.seqNoStats().getMaxSeqNo());
+        assertEquals(expectedPersistedDocCount - 1, indexShard.seqNoStats().getLocalCheckpoint());
+    }
+
+    protected void resolveCheckpointInfoResponseListener(ActionListener<CheckpointInfoResponse> listener, IndexShard primary) {
+        final CopyState copyState;
+        try {
+            copyState = new CopyState(
+                ReplicationCheckpoint.empty(primary.shardId, primary.getLatestReplicationCheckpoint().getCodec()),
+                primary
+            );
+        } catch (IOException e) {
+            logger.error("Unexpected error computing CopyState", e);
+            Assert.fail("Failed to compute copyState");
+            throw new UncheckedIOException(e);
+        }
+
+        try {
+            listener.onResponse(
+                new CheckpointInfoResponse(copyState.getCheckpoint(), copyState.getMetadataMap(), copyState.getInfosBytes())
+            );
+        } finally {
+            copyState.decRef();
+        }
+    }
+
+    protected void startReplicationAndAssertCancellation(
+        IndexShard replica,
+        IndexShard primary,
+        SegmentReplicationTargetService targetService
+    ) throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        final SegmentReplicationTarget target = targetService.startReplication(
+            replica,
+            primary.getLatestReplicationCheckpoint(),
+            new SegmentReplicationTargetService.SegmentReplicationListener() {
+                @Override
+                public void onReplicationDone(SegmentReplicationState state) {
+                    Assert.fail("Replication should not complete");
+                }
+
+                @Override
+                public void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                    assertFalse(sendShardFailure);
+                    latch.countDown();
+                }
+            }
+        );
+
+        latch.await(2, TimeUnit.SECONDS);
+        assertEquals("Should have resolved listener with failure", 0, latch.getCount());
+        assertNull(targetService.get(target.getId()));
+    }
+
+    protected IndexShard getRandomReplica(ReplicationGroup shards) {
+        return shards.getReplicas().get(randomInt(shards.getReplicas().size() - 1));
+    }
+
+    protected IndexShard failAndPromoteRandomReplica(ReplicationGroup shards) throws IOException {
+        IndexShard primary = shards.getPrimary();
+        final IndexShard newPrimary = getRandomReplica(shards);
+        shards.promoteReplicaToPrimary(newPrimary);
+        primary.close("demoted", true, false);
+        primary.store().close();
+        primary = shards.addReplicaWithExistingPath(primary.shardPath(), primary.routingEntry().currentNodeId());
+        shards.recoverReplica(primary);
+        return newPrimary;
+    }
+
+    protected void assertEqualCommittedSegments(IndexShard primary, IndexShard... replicas) throws IOException {
+        for (IndexShard replica : replicas) {
+            final SegmentInfos replicaInfos = replica.store().readLastCommittedSegmentsInfo();
+            final SegmentInfos primaryInfos = primary.store().readLastCommittedSegmentsInfo();
+            final Map<String, StoreFileMetadata> latestReplicaMetadata = replica.store().getSegmentMetadataMap(replicaInfos);
+            final Map<String, StoreFileMetadata> latestPrimaryMetadata = primary.store().getSegmentMetadataMap(primaryInfos);
+            final Store.RecoveryDiff diff = Store.segmentReplicationDiff(latestPrimaryMetadata, latestReplicaMetadata);
+            assertTrue(diff.different.isEmpty());
+            assertTrue(diff.missing.isEmpty());
+        }
+    }
+
+    protected void assertEqualTranslogOperations(ReplicationGroup shards, IndexShard primaryShard) throws IOException {
+        try (final Translog.Snapshot snapshot = getTranslog(primaryShard).newSnapshot()) {
+            List<Translog.Operation> operations = new ArrayList<>();
+            Translog.Operation op;
+            while ((op = snapshot.next()) != null) {
+                final Translog.Operation newOp = op;
+                operations.add(newOp);
+            }
+            for (IndexShard replica : shards.getReplicas()) {
+                try (final Translog.Snapshot replicaSnapshot = getTranslog(replica).newSnapshot()) {
+                    assertThat(replicaSnapshot, SnapshotMatchers.containsOperationsInAnyOrder(operations));
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/SegmentReplicationWithNodeToNodeIndexShardTests.java b/server/src/test/java/org/opensearch/index/shard/SegmentReplicationWithNodeToNodeIndexShardTests.java
new file mode 100644
index 0000000000000..c394101697b47
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/shard/SegmentReplicationWithNodeToNodeIndexShardTests.java
@@ -0,0 +1,712 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.lucene.index.SegmentInfos;
+import org.opensearch.action.admin.indices.flush.FlushRequest;
+import org.opensearch.action.delete.DeleteRequest;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.engine.DocIdSeqNoAndSource;
+import org.opensearch.index.engine.InternalEngine;
+import org.opensearch.index.engine.NRTReplicationEngine;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.replication.TestReplicationSource;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.CheckpointInfoResponse;
+import org.opensearch.indices.replication.GetSegmentFilesResponse;
+import org.opensearch.indices.replication.SegmentReplicationSource;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static java.util.Arrays.asList;
+import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationWithNodeToNodeIndexShardTests extends SegmentReplicationIndexShardTests {
+
+    public void testReplicaClosesWhileReplicating_AfterGetSegmentFiles() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            final int numDocs = shards.indexDocs(randomInt(10));
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    resolveCheckpointInfoResponseListener(listener, primary);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    // randomly resolve the listener, indicating the source has resolved.
+                    listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+                    targetService.beforeIndexShardClosed(replica.shardId, replica, Settings.EMPTY);
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(replica, primary, targetService);
+
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    public void testReplicaClosesWhileReplicating_AfterGetCheckpoint() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            final int numDocs = shards.indexDocs(randomInt(10));
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    // trigger a cancellation by closing the replica.
+                    targetService.beforeIndexShardClosed(replica.shardId, replica, Settings.EMPTY);
+                    resolveCheckpointInfoResponseListener(listener, primary);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    Assert.fail("Should not be reached");
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(replica, primary, targetService);
+
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    public void testCloseShardWhileGettingCheckpoint() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+
+                ActionListener<CheckpointInfoResponse> listener;
+
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    // set the listener, we will only fail it once we cancel the source.
+                    this.listener = listener;
+                    // shard is closing while we are copying files.
+                    targetService.beforeIndexShardClosed(replica.shardId, replica, Settings.EMPTY);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    Assert.fail("Unreachable");
+                }
+
+                @Override
+                public void cancel() {
+                    // simulate listener resolving, but only after we have issued a cancel from beforeIndexShardClosed .
+                    final RuntimeException exception = new CancellableThreads.ExecutionCancelledException("retryable action was cancelled");
+                    listener.onFailure(exception);
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(replica, primary, targetService);
+
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    public void testPrimaryCancelsExecution() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            final int numDocs = shards.indexDocs(randomInt(10));
+            primary.refresh("Test");
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    listener.onFailure(new CancellableThreads.ExecutionCancelledException("Cancelled"));
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {}
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(replica, primary, targetService);
+
+            shards.removeReplica(replica);
+            closeShards(replica);
+        }
+    }
+
+    public void testReplicaPromotedWhileReplicating() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard oldPrimary = shards.getPrimary();
+            final IndexShard nextPrimary = shards.getReplicas().get(0);
+
+            final int numDocs = shards.indexDocs(randomInt(10));
+            oldPrimary.refresh("Test");
+            shards.syncGlobalCheckpoint();
+
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final SegmentReplicationTargetService targetService = newTargetService(sourceFactory);
+            SegmentReplicationSource source = new TestReplicationSource() {
+                @Override
+                public void getCheckpointMetadata(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    ActionListener<CheckpointInfoResponse> listener
+                ) {
+                    resolveCheckpointInfoResponseListener(listener, oldPrimary);
+                    ShardRouting oldRouting = nextPrimary.shardRouting;
+                    try {
+                        shards.promoteReplicaToPrimary(nextPrimary);
+                    } catch (IOException e) {
+                        Assert.fail("Promotion should not fail");
+                    }
+                    targetService.shardRoutingChanged(nextPrimary, oldRouting, nextPrimary.shardRouting);
+                }
+
+                @Override
+                public void getSegmentFiles(
+                    long replicationId,
+                    ReplicationCheckpoint checkpoint,
+                    List<StoreFileMetadata> filesToFetch,
+                    IndexShard indexShard,
+                    ActionListener<GetSegmentFilesResponse> listener
+                ) {
+                    listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+                }
+            };
+            when(sourceFactory.get(any())).thenReturn(source);
+            startReplicationAndAssertCancellation(nextPrimary, oldPrimary, targetService);
+            // wait for replica to finish being promoted, and assert doc counts.
+            final CountDownLatch latch = new CountDownLatch(1);
+            nextPrimary.acquirePrimaryOperationPermit(new ActionListener<>() {
+                @Override
+                public void onResponse(Releasable releasable) {
+                    latch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    throw new AssertionError(e);
+                }
+            }, ThreadPool.Names.GENERIC, "");
+            latch.await();
+            assertEquals(nextPrimary.getEngine().getClass(), InternalEngine.class);
+            nextPrimary.refresh("test");
+
+            oldPrimary.close("demoted", false, false);
+            oldPrimary.store().close();
+            IndexShard newReplica = shards.addReplicaWithExistingPath(oldPrimary.shardPath(), oldPrimary.routingEntry().currentNodeId());
+            shards.recoverReplica(newReplica);
+
+            assertDocCount(nextPrimary, numDocs);
+            assertDocCount(newReplica, numDocs);
+
+            nextPrimary.refresh("test");
+            replicateSegments(nextPrimary, shards.getReplicas());
+            final List<DocIdSeqNoAndSource> docsAfterRecovery = getDocIdAndSeqNos(shards.getPrimary());
+            for (IndexShard shard : shards.getReplicas()) {
+                assertThat(shard.routingEntry().toString(), getDocIdAndSeqNos(shard), equalTo(docsAfterRecovery));
+            }
+        }
+    }
+
+    public void testReplicaReceivesGenIncrease() throws Exception {
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+            final int numDocs = randomIntBetween(10, 100);
+            shards.indexDocs(numDocs);
+            assertEquals(numDocs, primary.translogStats().estimatedNumberOfOperations());
+            assertEquals(numDocs, replica.translogStats().estimatedNumberOfOperations());
+            assertEquals(numDocs, primary.translogStats().getUncommittedOperations());
+            assertEquals(numDocs, replica.translogStats().getUncommittedOperations());
+            flushShard(primary, true);
+            replicateSegments(primary, shards.getReplicas());
+            assertEquals(0, primary.translogStats().estimatedNumberOfOperations());
+            assertEquals(0, replica.translogStats().estimatedNumberOfOperations());
+            assertEquals(0, primary.translogStats().getUncommittedOperations());
+            assertEquals(0, replica.translogStats().getUncommittedOperations());
+
+            final int additionalDocs = shards.indexDocs(randomIntBetween(numDocs + 1, numDocs + 10));
+
+            final int totalDocs = numDocs + additionalDocs;
+            primary.refresh("test");
+            replicateSegments(primary, shards.getReplicas());
+            assertEquals(additionalDocs, primary.translogStats().estimatedNumberOfOperations());
+            assertEquals(additionalDocs, replica.translogStats().estimatedNumberOfOperations());
+            assertEquals(additionalDocs, primary.translogStats().getUncommittedOperations());
+            assertEquals(additionalDocs, replica.translogStats().getUncommittedOperations());
+            flushShard(primary, true);
+            replicateSegments(primary, shards.getReplicas());
+
+            assertEqualCommittedSegments(primary, replica);
+            assertDocCount(primary, totalDocs);
+            assertDocCount(replica, totalDocs);
+            assertEquals(0, primary.translogStats().estimatedNumberOfOperations());
+            assertEquals(0, replica.translogStats().estimatedNumberOfOperations());
+            assertEquals(0, primary.translogStats().getUncommittedOperations());
+            assertEquals(0, replica.translogStats().getUncommittedOperations());
+        }
+    }
+
+    /**
+     * Verifies that commits on replica engine resulting from engine or reader close does not cleanup the temporary
+     * replication files from ongoing round of segment replication
+     */
+    public void testTemporaryFilesNotCleanup() throws Exception {
+        String mappings = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": { \"properties\": { \"foo\": { \"type\": \"keyword\"} }}}";
+        try (ReplicationGroup shards = createGroup(1, getIndexSettings(), mappings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primaryShard = shards.getPrimary();
+            final IndexShard replica = shards.getReplicas().get(0);
+
+            // Step 1. Ingest numDocs documents, commit to create commit point on primary & replicate
+            final int numDocs = randomIntBetween(100, 200);
+            logger.info("--> Inserting documents {}", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+            replicateSegments(primaryShard, shards.getReplicas());
+            shards.assertAllEqual(numDocs);
+
+            // Step 2. Ingest numDocs documents again to create a new commit on primary
+            logger.info("--> Ingest {} docs again", numDocs);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.flush(new FlushRequest().waitIfOngoing(true).force(true));
+
+            // Step 3. Copy segment files to replica shard but prevent commit
+            final CountDownLatch countDownLatch = new CountDownLatch(1);
+            Map<String, StoreFileMetadata> primaryMetadata;
+            try (final GatedCloseable<SegmentInfos> segmentInfosSnapshot = primaryShard.getSegmentInfosSnapshot()) {
+                final SegmentInfos primarySegmentInfos = segmentInfosSnapshot.get();
+                primaryMetadata = primaryShard.store().getSegmentMetadataMap(primarySegmentInfos);
+            }
+            final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            final IndicesService indicesService = mock(IndicesService.class);
+            when(indicesService.getShardOrNull(replica.shardId)).thenReturn(replica);
+            final SegmentReplicationTargetService targetService = new SegmentReplicationTargetService(
+                threadPool,
+                new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+                mock(TransportService.class),
+                sourceFactory,
+                indicesService,
+                clusterService
+            );
+            final Consumer<IndexShard> runnablePostGetFiles = (indexShard) -> {
+                try {
+                    Collection<String> temporaryFiles = Stream.of(indexShard.store().directory().listAll())
+                        .filter(name -> name.startsWith(SegmentReplicationTarget.REPLICATION_PREFIX))
+                        .collect(Collectors.toList());
+
+                    // Step 4. Perform a commit on replica shard.
+                    NRTReplicationEngine engine = (NRTReplicationEngine) indexShard.getEngine();
+                    engine.updateSegments(engine.getSegmentInfosSnapshot().get());
+
+                    // Step 5. Validate temporary files are not deleted from store.
+                    Collection<String> replicaStoreFiles = List.of(indexShard.store().directory().listAll());
+                    assertTrue(replicaStoreFiles.containsAll(temporaryFiles));
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            };
+            SegmentReplicationSource segmentReplicationSource = getSegmentReplicationSource(
+                primaryShard,
+                (repId) -> targetService.get(repId),
+                runnablePostGetFiles
+            );
+            when(sourceFactory.get(any())).thenReturn(segmentReplicationSource);
+            targetService.startReplication(
+                replica,
+                primaryShard.getLatestReplicationCheckpoint(),
+                getTargetListener(primaryShard, replica, primaryMetadata, countDownLatch)
+            );
+            countDownLatch.await(30, TimeUnit.SECONDS);
+            assertEquals("Replication failed", 0, countDownLatch.getCount());
+            shards.assertAllEqual(numDocs);
+        }
+    }
+
+    public void testReplicaReceivesLowerGeneration() throws Exception {
+        // when a replica gets incoming segments that are lower than what it currently has on disk.
+        // this can happen when a replica is promoted that is further behind the other replicas.
+        try (ReplicationGroup shards = createGroup(2, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primary = shards.getPrimary();
+            final IndexShard behindReplicaBeforeRestart = shards.getReplicas().get(0);
+            final IndexShard replica_2 = shards.getReplicas().get(1);
+            int numDocs = randomIntBetween(10, 100);
+            int totalDocs = numDocs;
+            shards.indexDocs(numDocs);
+            flushShard(primary, true);
+            replicateSegments(primary, List.of(behindReplicaBeforeRestart));
+            numDocs = randomIntBetween(numDocs + 1, numDocs + 10);
+            totalDocs += numDocs;
+            shards.indexDocs(numDocs);
+            flushShard(primary, true);
+            flushShard(primary, true);
+            flushShard(primary, true);
+            replicateSegments(primary, List.of(behindReplicaBeforeRestart));
+
+            // close behindReplicaBeforeRestart - we will re-open it after replica_2 is promoted as new primary.
+            assertEqualCommittedSegments(primary, behindReplicaBeforeRestart);
+
+            assertDocCount(behindReplicaBeforeRestart, totalDocs);
+            assertDocCount(replica_2, 0);
+
+            shards.promoteReplicaToPrimary(replica_2).get();
+            primary.close("demoted", randomBoolean(), false);
+            primary.store().close();
+            IndexShard oldPrimary = shards.addReplicaWithExistingPath(primary.shardPath(), primary.routingEntry().currentNodeId());
+            shards.recoverReplica(oldPrimary);
+
+            behindReplicaBeforeRestart.close("restart", false, false);
+            behindReplicaBeforeRestart.store().close();
+            shards.removeReplica(behindReplicaBeforeRestart);
+            final IndexShard behindReplicaAfterRestart = shards.addReplicaWithExistingPath(
+                behindReplicaBeforeRestart.shardPath(),
+                behindReplicaBeforeRestart.routingEntry().currentNodeId()
+            );
+            shards.recoverReplica(behindReplicaAfterRestart);
+
+            numDocs = randomIntBetween(numDocs + 1, numDocs + 10);
+            totalDocs += numDocs;
+            shards.indexDocs(numDocs);
+            flushShard(replica_2, false);
+            replicateSegments(replica_2, shards.getReplicas());
+            assertEqualCommittedSegments(replica_2, oldPrimary, behindReplicaAfterRestart);
+            assertDocCount(replica_2, totalDocs);
+            assertDocCount(oldPrimary, totalDocs);
+            assertDocCount(behindReplicaAfterRestart, totalDocs);
+        }
+    }
+
+    // Todo: Move this test to SegmentReplicationIndexShardTests so that it runs for both node-node & remote store
+    public void testPrimaryRelocation() throws Exception {
+        final IndexShard primarySource = newStartedShard(true, getIndexSettings());
+        int totalOps = randomInt(10);
+        for (int i = 0; i < totalOps; i++) {
+            indexDoc(primarySource, "_doc", Integer.toString(i));
+        }
+        IndexShardTestCase.updateRoutingEntry(primarySource, primarySource.routingEntry().relocate(randomAlphaOfLength(10), -1));
+        final IndexShard primaryTarget = newShard(
+            primarySource.routingEntry().getTargetRelocatingShard(),
+            getIndexSettings(),
+            new NRTReplicationEngineFactory()
+        );
+        updateMappings(primaryTarget, primarySource.indexSettings().getIndexMetadata());
+
+        Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction = (shardList) -> {
+            try {
+                assert shardList.size() >= 2;
+                final IndexShard primary = shardList.get(0);
+                return replicateSegments(primary, shardList.subList(1, shardList.size()));
+            } catch (IOException | InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        };
+        recoverReplica(primaryTarget, primarySource, true, replicatePrimaryFunction);
+
+        // check that local checkpoint of new primary is properly tracked after primary relocation
+        assertThat(primaryTarget.getLocalCheckpoint(), equalTo(totalOps - 1L));
+        assertThat(
+            primaryTarget.getReplicationTracker()
+                .getTrackedLocalCheckpointForShard(primaryTarget.routingEntry().allocationId().getId())
+                .getLocalCheckpoint(),
+            equalTo(totalOps - 1L)
+        );
+        assertDocCount(primaryTarget, totalOps);
+        closeShards(primarySource, primaryTarget);
+    }
+
+    // Todo: Move this test to SegmentReplicationIndexShardTests so that it runs for both node-node & remote store
+    public void testNRTReplicaPromotedAsPrimary() throws Exception {
+        try (ReplicationGroup shards = createGroup(2, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard oldPrimary = shards.getPrimary();
+            final IndexShard nextPrimary = shards.getReplicas().get(0);
+            final IndexShard replica = shards.getReplicas().get(1);
+
+            // 1. Create ops that are in the index and xlog of both shards but not yet part of a commit point.
+            final int numDocs = shards.indexDocs(randomInt(10));
+
+            // refresh and copy the segments over.
+            oldPrimary.refresh("Test");
+            replicateSegments(oldPrimary, shards.getReplicas());
+
+            // at this point both shards should have numDocs persisted and searchable.
+            assertDocCounts(oldPrimary, numDocs, numDocs);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertDocCounts(shard, numDocs, numDocs);
+            }
+            assertEqualTranslogOperations(shards, oldPrimary);
+
+            // 2. Create ops that are in the replica's xlog, not in the index.
+            // index some more into both but don't replicate. replica will have only numDocs searchable, but should have totalDocs
+            // persisted.
+            final int additonalDocs = shards.indexDocs(randomInt(10));
+            final int totalDocs = numDocs + additonalDocs;
+
+            assertDocCounts(oldPrimary, totalDocs, totalDocs);
+            assertEqualTranslogOperations(shards, oldPrimary);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertDocCounts(shard, totalDocs, numDocs);
+            }
+            assertEquals(totalDocs, oldPrimary.translogStats().estimatedNumberOfOperations());
+            assertEquals(totalDocs, oldPrimary.translogStats().estimatedNumberOfOperations());
+            assertEquals(totalDocs, nextPrimary.translogStats().estimatedNumberOfOperations());
+            assertEquals(totalDocs, replica.translogStats().estimatedNumberOfOperations());
+            assertEquals(totalDocs, nextPrimary.translogStats().getUncommittedOperations());
+            assertEquals(totalDocs, replica.translogStats().getUncommittedOperations());
+
+            // promote the replica
+            shards.syncGlobalCheckpoint();
+            shards.promoteReplicaToPrimary(nextPrimary);
+
+            // close and start the oldPrimary as a replica.
+            oldPrimary.close("demoted", false, false);
+            oldPrimary.store().close();
+            oldPrimary = shards.addReplicaWithExistingPath(oldPrimary.shardPath(), oldPrimary.routingEntry().currentNodeId());
+            shards.recoverReplica(oldPrimary);
+
+            assertEquals(NRTReplicationEngine.class, oldPrimary.getEngine().getClass());
+            assertEquals(InternalEngine.class, nextPrimary.getEngine().getClass());
+            assertDocCounts(nextPrimary, totalDocs, totalDocs);
+            assertEquals(0, nextPrimary.translogStats().estimatedNumberOfOperations());
+
+            // refresh and push segments to our other replica.
+            nextPrimary.refresh("test");
+            replicateSegments(nextPrimary, asList(replica));
+
+            for (IndexShard shard : shards) {
+                assertConsistentHistoryBetweenTranslogAndLucene(shard);
+            }
+            final List<DocIdSeqNoAndSource> docsAfterRecovery = getDocIdAndSeqNos(shards.getPrimary());
+            for (IndexShard shard : shards.getReplicas()) {
+                assertThat(shard.routingEntry().toString(), getDocIdAndSeqNos(shard), equalTo(docsAfterRecovery));
+            }
+        }
+    }
+
+    // Todo: Move this test to SegmentReplicationIndexShardTests so that it runs for both node-node & remote store
+    public void testReplicaRestarts() throws Exception {
+        try (ReplicationGroup shards = createGroup(3, getIndexSettings(), new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            IndexShard primary = shards.getPrimary();
+            // 1. Create ops that are in the index and xlog of both shards but not yet part of a commit point.
+            final int numDocs = shards.indexDocs(randomInt(10));
+            logger.info("--> Index {} documents on primary", numDocs);
+
+            // refresh and copy the segments over.
+            if (randomBoolean()) {
+                flushShard(primary);
+            }
+            primary.refresh("Test");
+            logger.info("--> Replicate segments");
+            replicateSegments(primary, shards.getReplicas());
+
+            // at this point both shards should have numDocs persisted and searchable.
+            logger.info("--> Verify doc count");
+            assertDocCounts(primary, numDocs, numDocs);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertDocCounts(shard, numDocs, numDocs);
+            }
+
+            final int i1 = randomInt(5);
+            logger.info("--> Index {} more docs", i1);
+            for (int i = 0; i < i1; i++) {
+                shards.indexDocs(randomInt(10));
+
+                // randomly restart a replica
+                final IndexShard replicaToRestart = getRandomReplica(shards);
+                logger.info("--> Restarting replica {}", replicaToRestart.shardId);
+                replicaToRestart.close("restart", false, false);
+                replicaToRestart.store().close();
+                shards.removeReplica(replicaToRestart);
+                final IndexShard newReplica = shards.addReplicaWithExistingPath(
+                    replicaToRestart.shardPath(),
+                    replicaToRestart.routingEntry().currentNodeId()
+                );
+                logger.info("--> Recover newReplica {}", newReplica.shardId);
+                shards.recoverReplica(newReplica);
+
+                // refresh and push segments to our other replicas.
+                if (randomBoolean()) {
+                    failAndPromoteRandomReplica(shards);
+                }
+                flushShard(shards.getPrimary());
+                replicateSegments(shards.getPrimary(), shards.getReplicas());
+            }
+            primary = shards.getPrimary();
+
+            // refresh and push segments to our other replica.
+            flushShard(primary);
+            replicateSegments(primary, shards.getReplicas());
+
+            for (IndexShard shard : shards) {
+                assertConsistentHistoryBetweenTranslogAndLucene(shard);
+            }
+            final List<DocIdSeqNoAndSource> docsAfterReplication = getDocIdAndSeqNos(shards.getPrimary());
+            for (IndexShard shard : shards.getReplicas()) {
+                assertThat(shard.routingEntry().toString(), getDocIdAndSeqNos(shard), equalTo(docsAfterReplication));
+            }
+        }
+    }
+
+    // Todo: Move this test to SegmentReplicationIndexShardTests so that it runs for both node-node & remote store
+    public void testSegmentReplication_Index_Update_Delete() throws Exception {
+        String mappings = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": { \"properties\": { \"foo\": { \"type\": \"keyword\"} }}}";
+        try (ReplicationGroup shards = createGroup(2, getIndexSettings(), mappings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final IndexShard primaryShard = shards.getPrimary();
+
+            final int numDocs = randomIntBetween(100, 200);
+            for (int i = 0; i < numDocs; i++) {
+                shards.index(new IndexRequest(index.getName()).id(String.valueOf(i)).source("{\"foo\": \"bar\"}", MediaTypeRegistry.JSON));
+            }
+
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.refresh("Test");
+            replicateSegments(primaryShard, shards.getReplicas());
+
+            shards.assertAllEqual(numDocs);
+
+            for (int i = 0; i < numDocs; i++) {
+                // randomly update docs.
+                if (randomBoolean()) {
+                    shards.index(
+                        new IndexRequest(index.getName()).id(String.valueOf(i)).source("{ \"foo\" : \"baz\" }", MediaTypeRegistry.JSON)
+                    );
+                }
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.refresh("Test");
+            replicateSegments(primaryShard, shards.getReplicas());
+            shards.assertAllEqual(numDocs);
+
+            final List<DocIdSeqNoAndSource> docs = getDocIdAndSeqNos(primaryShard);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertEquals(getDocIdAndSeqNos(shard), docs);
+            }
+            for (int i = 0; i < numDocs; i++) {
+                // randomly delete.
+                if (randomBoolean()) {
+                    shards.delete(new DeleteRequest(index.getName()).id(String.valueOf(i)));
+                }
+            }
+            assertEqualTranslogOperations(shards, primaryShard);
+            primaryShard.refresh("Test");
+            replicateSegments(primaryShard, shards.getReplicas());
+            final List<DocIdSeqNoAndSource> docsAfterDelete = getDocIdAndSeqNos(primaryShard);
+            for (IndexShard shard : shards.getReplicas()) {
+                assertEquals(getDocIdAndSeqNos(shard), docsAfterDelete);
+            }
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/shard/ShardGetServiceTests.java b/server/src/test/java/org/opensearch/index/shard/ShardGetServiceTests.java
index 5dd053574268e..0f27bc2bd126b 100644
--- a/server/src/test/java/org/opensearch/index/shard/ShardGetServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/ShardGetServiceTests.java
@@ -34,7 +34,8 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.VersionConflictEngineException;
@@ -56,7 +57,6 @@ public void testGetForUpdate() throws IOException {
             .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
             .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
             .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
-
             .build();
         IndexMetadata metadata = IndexMetadata.builder("test")
             .putMapping("{ \"properties\": { \"foo\":  { \"type\": \"text\"}}}")
@@ -74,7 +74,7 @@ public void testGetForUpdate() throws IOException {
             assertEquals(searcher.getIndexReader().maxDoc(), 1); // we refreshed
         }
 
-        Engine.IndexResult test1 = indexDoc(primary, "1", "{\"foo\" : \"baz\"}", XContentType.JSON, "foobar");
+        Engine.IndexResult test1 = indexDoc(primary, "1", "{\"foo\" : \"baz\"}", MediaTypeRegistry.JSON, "foobar");
         assertTrue(primary.getEngine().refreshNeeded());
         GetResult testGet1 = primary.getService().getForUpdate("1", UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM);
         assertEquals(new String(testGet1.source(), StandardCharsets.UTF_8), "{\"foo\" : \"baz\"}");
@@ -89,7 +89,7 @@ public void testGetForUpdate() throws IOException {
         }
 
         // now again from the reader
-        Engine.IndexResult test2 = indexDoc(primary, "1", "{\"foo\" : \"baz\"}", XContentType.JSON, "foobar");
+        Engine.IndexResult test2 = indexDoc(primary, "1", "{\"foo\" : \"baz\"}", MediaTypeRegistry.JSON, "foobar");
         assertTrue(primary.getEngine().refreshNeeded());
         testGet1 = primary.getService().getForUpdate("1", UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM);
         assertEquals(new String(testGet1.source(), StandardCharsets.UTF_8), "{\"foo\" : \"baz\"}");
@@ -157,7 +157,7 @@ private void runGetFromTranslogWithOptions(
             assertEquals(searcher.getIndexReader().maxDoc(), 1); // we refreshed
         }
 
-        Engine.IndexResult test1 = indexDoc(primary, "1", docToIndex, XContentType.JSON, "foobar");
+        Engine.IndexResult test1 = indexDoc(primary, "1", docToIndex, MediaTypeRegistry.JSON, "foobar");
         assertTrue(primary.getEngine().refreshNeeded());
         GetResult testGet1 = primary.getService().getForUpdate("1", UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM);
         assertEquals(new String(testGet1.source() == null ? new byte[0] : testGet1.source(), StandardCharsets.UTF_8), expectedResult);
@@ -171,7 +171,7 @@ private void runGetFromTranslogWithOptions(
             assertEquals(searcher.getIndexReader().maxDoc(), 2);
         }
 
-        Engine.IndexResult test2 = indexDoc(primary, "2", docToIndex, XContentType.JSON, "foobar");
+        Engine.IndexResult test2 = indexDoc(primary, "2", docToIndex, MediaTypeRegistry.JSON, "foobar");
         assertTrue(primary.getEngine().refreshNeeded());
         GetResult testGet2 = primary.getService()
             .get("2", new String[] { "foo" }, true, 1, VersionType.INTERNAL, FetchSourceContext.FETCH_SOURCE);
diff --git a/server/src/test/java/org/opensearch/index/shard/ShardIdTests.java b/server/src/test/java/org/opensearch/index/shard/ShardIdTests.java
index 6c5ae98bf6074..3a925602d7821 100644
--- a/server/src/test/java/org/opensearch/index/shard/ShardIdTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/ShardIdTests.java
@@ -33,7 +33,8 @@
 package org.opensearch.index.shard;
 
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 public class ShardIdTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/index/shard/ShardPathTests.java b/server/src/test/java/org/opensearch/index/shard/ShardPathTests.java
index beda468b45fb0..3f9ab703d2336 100644
--- a/server/src/test/java/org/opensearch/index/shard/ShardPathTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/ShardPathTests.java
@@ -33,14 +33,16 @@
 
 import org.opensearch.cluster.routing.AllocationId;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.env.Environment;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
+import org.opensearch.gateway.WriteStateException;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.file.Path;
 
+import static org.opensearch.env.Environment.PATH_SHARED_DATA_SETTING;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
 
@@ -50,7 +52,7 @@ public void testLoadShardPath() throws IOException {
             ShardId shardId = new ShardId("foo", "0xDEADBEEF", 0);
             Path[] paths = env.availableShardPaths(shardId);
             Path path = randomFrom(paths);
-            ShardStateMetadata.FORMAT.writeAndCleanup(new ShardStateMetadata(true, "0xDEADBEEF", AllocationId.newInitializing()), path);
+            writeShardStateMetadata("0xDEADBEEF", path);
             ShardPath shardPath = ShardPath.loadShardPath(logger, env, shardId, "");
             assertEquals(path, shardPath.getDataPath());
             assertEquals("0xDEADBEEF", shardPath.getShardId().getIndex().getUUID());
@@ -66,7 +68,7 @@ public void testFailLoadShardPathOnMultiState() throws IOException {
             ShardId shardId = new ShardId("foo", indexUUID, 0);
             Path[] paths = env.availableShardPaths(shardId);
             assumeTrue("This test tests multi data.path but we only got one", paths.length > 1);
-            ShardStateMetadata.FORMAT.writeAndCleanup(new ShardStateMetadata(true, indexUUID, AllocationId.newInitializing()), paths);
+            writeShardStateMetadata(indexUUID, paths);
             Exception e = expectThrows(IllegalStateException.class, () -> ShardPath.loadShardPath(logger, env, shardId, ""));
             assertThat(e.getMessage(), containsString("more than one shard state found"));
         }
@@ -77,7 +79,7 @@ public void testFailLoadShardPathIndexUUIDMissmatch() throws IOException {
             ShardId shardId = new ShardId("foo", "foobar", 0);
             Path[] paths = env.availableShardPaths(shardId);
             Path path = randomFrom(paths);
-            ShardStateMetadata.FORMAT.writeAndCleanup(new ShardStateMetadata(true, "0xDEADBEEF", AllocationId.newInitializing()), path);
+            writeShardStateMetadata("0xDEADBEEF", path);
             Exception e = expectThrows(IllegalStateException.class, () -> ShardPath.loadShardPath(logger, env, shardId, ""));
             assertThat(e.getMessage(), containsString("expected: foobar on shard path"));
         }
@@ -108,9 +110,7 @@ public void testGetRootPaths() throws IOException {
         if (useCustomDataPath) {
             final Path path = createTempDir();
             customDataPath = "custom";
-            nodeSettings = Settings.builder()
-                .put(Environment.PATH_SHARED_DATA_SETTING.getKey(), path.toAbsolutePath().toAbsolutePath())
-                .build();
+            nodeSettings = Settings.builder().put(PATH_SHARED_DATA_SETTING.getKey(), path.toAbsolutePath().toAbsolutePath()).build();
             customPath = path.resolve("custom").resolve("0");
         } else {
             customPath = null;
@@ -121,7 +121,7 @@ public void testGetRootPaths() throws IOException {
             ShardId shardId = new ShardId("foo", indexUUID, 0);
             Path[] paths = env.availableShardPaths(shardId);
             Path path = randomFrom(paths);
-            ShardStateMetadata.FORMAT.writeAndCleanup(new ShardStateMetadata(true, indexUUID, AllocationId.newInitializing()), path);
+            writeShardStateMetadata(indexUUID, path);
             ShardPath shardPath = ShardPath.loadShardPath(logger, env, shardId, customDataPath);
             boolean found = false;
             for (Path p : env.nodeDataPaths()) {
@@ -148,4 +148,27 @@ public void testGetRootPaths() throws IOException {
         }
     }
 
+    public void testLoadFileCachePath() throws IOException {
+        Settings searchNodeSettings = Settings.builder().put("node.roles", "search").build();
+
+        try (NodeEnvironment env = newNodeEnvironment(searchNodeSettings)) {
+            ShardId shardId = new ShardId("foo", "0xDEADBEEF", 0);
+            Path fileCachePath = env.fileCacheNodePath().fileCachePath;
+            writeShardStateMetadata("0xDEADBEEF", fileCachePath);
+            ShardPath shardPath = ShardPath.loadFileCachePath(env, shardId);
+
+            assertTrue(shardPath.getDataPath().startsWith(fileCachePath));
+            assertFalse(shardPath.getShardStatePath().startsWith(fileCachePath));
+
+            assertEquals("0xDEADBEEF", shardPath.getShardId().getIndex().getUUID());
+            assertEquals("foo", shardPath.getShardId().getIndexName());
+        }
+    }
+
+    private static void writeShardStateMetadata(String indexUUID, Path... paths) throws WriteStateException {
+        ShardStateMetadata.FORMAT.writeAndCleanup(
+            new ShardStateMetadata(true, indexUUID, AllocationId.newInitializing(), ShardStateMetadata.IndexDataLocation.LOCAL),
+            paths
+        );
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/shard/ShardSplittingQueryTests.java b/server/src/test/java/org/opensearch/index/shard/ShardSplittingQueryTests.java
index b39ff0c9b97b3..03b4ab684e763 100644
--- a/server/src/test/java/org/opensearch/index/shard/ShardSplittingQueryTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/ShardSplittingQueryTests.java
@@ -38,7 +38,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexSearcher;
@@ -46,15 +45,16 @@
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.mapper.IdFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.RoutingFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -88,7 +88,7 @@ public void testSplitOnID() throws IOException {
                     docs.add(
                         Arrays.asList(
                             new StringField(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(j)), Field.Store.YES),
-                            new StringField(TypeFieldMapper.NAME, "__nested", Field.Store.YES),
+                            new StringField(NestedPathFieldMapper.NAME, "__nested", Field.Store.YES),
                             new SortedNumericDocValuesField("shard_id", shardId)
                         )
                     );
@@ -142,7 +142,7 @@ public void testSplitOnRouting() throws IOException {
                     docs.add(
                         Arrays.asList(
                             new StringField(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(j)), Field.Store.YES),
-                            new StringField(TypeFieldMapper.NAME, "__nested", Field.Store.YES),
+                            new StringField(NestedPathFieldMapper.NAME, "__nested", Field.Store.YES),
                             new SortedNumericDocValuesField("shard_id", shardId)
                         )
                     );
@@ -215,7 +215,7 @@ public void testSplitOnIdOrRouting() throws IOException {
                     docs.add(
                         Arrays.asList(
                             new StringField(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(j)), Field.Store.YES),
-                            new StringField(TypeFieldMapper.NAME, "__nested", Field.Store.YES),
+                            new StringField(NestedPathFieldMapper.NAME, "__nested", Field.Store.YES),
                             new SortedNumericDocValuesField("shard_id", shardId)
                         )
                     );
@@ -258,7 +258,7 @@ public void testSplitOnRoutingPartitioned() throws IOException {
                     docs.add(
                         Arrays.asList(
                             new StringField(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(j)), Field.Store.YES),
-                            new StringField(TypeFieldMapper.NAME, "__nested", Field.Store.YES),
+                            new StringField(NestedPathFieldMapper.NAME, "__nested", Field.Store.YES),
                             new SortedNumericDocValuesField("shard_id", shardId)
                         )
                     );
@@ -326,7 +326,7 @@ void assertSplit(Directory dir, IndexMetadata metadata, int targetShardId, boole
                         }
                         assertEquals(shard_id.docID(), doc);
                         long shardID = shard_id.nextValue();
-                        BytesRef id = reader.document(doc).getBinaryValue("_id");
+                        BytesRef id = reader.storedFields().document(doc).getBinaryValue("_id");
                         String actualId = Uid.decodeId(id.bytes, id.offset, id.length);
                         assertNotEquals(ctx.reader() + " docID: " + doc + " actualID: " + actualId, shardID, targetShardId);
                     }
diff --git a/server/src/test/java/org/opensearch/index/shard/ShardUtilsTests.java b/server/src/test/java/org/opensearch/index/shard/ShardUtilsTests.java
index 25a385f157b5c..14c925939ba9d 100644
--- a/server/src/test/java/org/opensearch/index/shard/ShardUtilsTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/ShardUtilsTests.java
@@ -39,7 +39,8 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/index/shard/StoreRecoveryTests.java b/server/src/test/java/org/opensearch/index/shard/StoreRecoveryTests.java
index c325ac6bc754e..c1a51bb780f61 100644
--- a/server/src/test/java/org/opensearch/index/shard/StoreRecoveryTests.java
+++ b/server/src/test/java/org/opensearch/index/shard/StoreRecoveryTests.java
@@ -56,12 +56,13 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -108,7 +109,7 @@ public void testAddIndices() throws IOException {
             writer.close();
         }
         StoreRecovery storeRecovery = new StoreRecovery(new ShardId("foo", "bar", 1), logger);
-        RecoveryState.Index indexStats = new RecoveryState.Index();
+        ReplicationLuceneIndex indexStats = new ReplicationLuceneIndex();
         Directory target = newFSDirectory(createTempDir());
         final long maxSeqNo = randomNonNegativeLong();
         final long maxUnsafeAutoIdTimestamp = randomNonNegativeLong();
@@ -174,7 +175,7 @@ public void testSplitShard() throws IOException {
         writer.commit();
         writer.close();
         StoreRecovery storeRecovery = new StoreRecovery(new ShardId("foo", "bar", 1), logger);
-        RecoveryState.Index indexStats = new RecoveryState.Index();
+        ReplicationLuceneIndex indexStats = new ReplicationLuceneIndex();
         Directory target = newFSDirectory(createTempDir());
         final long maxSeqNo = randomNonNegativeLong();
         final long maxUnsafeAutoIdTimestamp = randomNonNegativeLong();
@@ -250,7 +251,7 @@ public void testSplitShard() throws IOException {
     public void testStatsDirWrapper() throws IOException {
         Directory dir = newDirectory();
         Directory target = newDirectory();
-        RecoveryState.Index indexStats = new RecoveryState.Index();
+        ReplicationLuceneIndex indexStats = new ReplicationLuceneIndex();
         StoreRecovery.StatsDirectoryWrapper wrapper = new StoreRecovery.StatsDirectoryWrapper(target, indexStats);
         try (IndexOutput output = dir.createOutput("foo.bar", IOContext.DEFAULT)) {
             CodecUtil.writeHeader(output, "foo", 0);
diff --git a/server/src/test/java/org/opensearch/index/similarity/ScriptedSimilarityTests.java b/server/src/test/java/org/opensearch/index/similarity/ScriptedSimilarityTests.java
index ef935ba64f1ca..f4282b8221c05 100644
--- a/server/src/test/java/org/opensearch/index/similarity/ScriptedSimilarityTests.java
+++ b/server/src/test/java/org/opensearch/index/similarity/ScriptedSimilarityTests.java
@@ -111,10 +111,9 @@ public double execute(
                 ) {
 
                     StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
-                    if (Arrays.stream(stackTraceElements)
-                        .anyMatch(
-                            ste -> { return ste.getClassName().endsWith(".TermScorer") && ste.getMethodName().equals("score"); }
-                        ) == false) {
+                    if (Arrays.stream(stackTraceElements).anyMatch(ste -> {
+                        return ste.getClassName().endsWith(".TermScorer") && ste.getMethodName().equals("score");
+                    }) == false) {
                         // this might happen when computing max scores
                         return Float.MAX_VALUE;
                     }
@@ -210,10 +209,9 @@ public double execute(
                 ) {
 
                     StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
-                    if (Arrays.stream(stackTraceElements)
-                        .anyMatch(
-                            ste -> { return ste.getClassName().endsWith(".TermScorer") && ste.getMethodName().equals("score"); }
-                        ) == false) {
+                    if (Arrays.stream(stackTraceElements).anyMatch(ste -> {
+                        return ste.getClassName().endsWith(".TermScorer") && ste.getMethodName().equals("score");
+                    }) == false) {
                         // this might happen when computing max scores
                         return Float.MAX_VALUE;
                     }
diff --git a/server/src/test/java/org/opensearch/index/similarity/SimilarityServiceTests.java b/server/src/test/java/org/opensearch/index/similarity/SimilarityServiceTests.java
index eb666f1206c26..b39e823dac689 100644
--- a/server/src/test/java/org/opensearch/index/similarity/SimilarityServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/similarity/SimilarityServiceTests.java
@@ -40,8 +40,8 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/index/similarity/SimilarityTests.java b/server/src/test/java/org/opensearch/index/similarity/SimilarityTests.java
index 625064820df44..1203e15fbebd6 100644
--- a/server/src/test/java/org/opensearch/index/similarity/SimilarityTests.java
+++ b/server/src/test/java/org/opensearch/index/similarity/SimilarityTests.java
@@ -45,18 +45,17 @@
 import org.apache.lucene.search.similarities.LMJelinekMercerSimilarity;
 import org.apache.lucene.search.similarities.LambdaTTF;
 import org.apache.lucene.search.similarities.NormalizationH2;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -275,17 +274,16 @@ public void testResolveSimilaritiesFromMapping_LMJelinekMercer() throws IOExcept
     }
 
     public void testResolveSimilaritiesFromMapping_Unknown() throws IOException {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("field1")
-                .field("type", "text")
-                .field("similarity", "unknown_similarity")
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("field1")
+            .field("type", "text")
+            .field("similarity", "unknown_similarity")
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         IndexService indexService = createIndex("foo");
         try {
diff --git a/server/src/test/java/org/opensearch/index/snapshots/blobstore/FileInfoTests.java b/server/src/test/java/org/opensearch/index/snapshots/blobstore/FileInfoTests.java
index 666a79c041e90..3db9aeb9264a7 100644
--- a/server/src/test/java/org/opensearch/index/snapshots/blobstore/FileInfoTests.java
+++ b/server/src/test/java/org/opensearch/index/snapshots/blobstore/FileInfoTests.java
@@ -34,14 +34,13 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Version;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot.FileInfo;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.test.OpenSearchTestCase;
@@ -73,7 +72,7 @@ public void testToFromXContent() throws IOException {
             );
             ByteSizeValue size = new ByteSizeValue(Math.abs(randomLong()));
             BlobStoreIndexShardSnapshot.FileInfo info = new BlobStoreIndexShardSnapshot.FileInfo("_foobar", meta, size);
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON).prettyPrint();
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON).prettyPrint();
             BlobStoreIndexShardSnapshot.FileInfo.toXContent(info, builder, ToXContent.EMPTY_PARAMS);
             byte[] xcontent = BytesReference.toBytes(BytesReference.bytes(shuffleXContent(builder)));
 
@@ -126,7 +125,7 @@ public void testInvalidFieldsInFromXContent() throws IOException {
                     fail("shouldn't be here");
             }
 
-            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
             builder.startObject();
             builder.field(FileInfo.NAME, name);
             builder.field(FileInfo.PHYSICAL_NAME, physicalName);
diff --git a/server/src/test/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshotTests.java b/server/src/test/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshotTests.java
new file mode 100644
index 0000000000000..38c4bb781ce06
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/snapshots/blobstore/RemoteStoreShardShallowCopySnapshotTests.java
@@ -0,0 +1,226 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.snapshots.blobstore;
+
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+import static org.hamcrest.Matchers.containsString;
+
+public class RemoteStoreShardShallowCopySnapshotTests extends OpenSearchTestCase {
+
+    public void testToXContent() throws IOException {
+        String snapshot = "test-snapshot";
+        long indexVersion = 1;
+        long primaryTerm = 3;
+        long commitGeneration = 5;
+        long startTime = 123;
+        long time = 123;
+        int totalFileCount = 5;
+        long totalSize = 5;
+        String indexUUID = "syzhajds-ashdlfj";
+        String remoteStoreRepository = "test-rs-repository";
+        String repositoryBasePath = "test-repo-basepath";
+        List<String> fileNames = new ArrayList<>(5);
+        fileNames.addAll(Arrays.asList("file1", "file2", "file3", "file4", "file5"));
+        RemoteStoreShardShallowCopySnapshot shardShallowCopySnapshot = new RemoteStoreShardShallowCopySnapshot(
+            snapshot,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            startTime,
+            time,
+            totalFileCount,
+            totalSize,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath,
+            fileNames
+        );
+        String actual;
+        try (XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder()) {
+            builder.startObject();
+            shardShallowCopySnapshot.toXContent(builder, ToXContent.EMPTY_PARAMS);
+            builder.endObject();
+            actual = builder.toString();
+        }
+        String expectedXContent = "{\"version\":\"1\",\"name\":\"test-snapshot\",\"index_version\":1,\"start_time\":123,\"time\":123,"
+            + "\"number_of_files\":5,\"total_size\":5,\"index_uuid\":\"syzhajds-ashdlfj\",\"remote_store_repository\":"
+            + "\"test-rs-repository\",\"commit_generation\":5,\"primary_term\":3,\"remote_store_repository_base_path\":"
+            + "\"test-repo-basepath\",\"file_names\":[\"file1\",\"file2\",\"file3\",\"file4\",\"file5\"]}";
+        assert Objects.equals(actual, expectedXContent) : "xContent is " + actual;
+    }
+
+    public void testFromXContent() throws IOException {
+        String snapshot = "test-snapshot";
+        long indexVersion = 1;
+        long primaryTerm = 3;
+        long commitGeneration = 5;
+        long startTime = 123;
+        long time = 123;
+        int totalFileCount = 5;
+        long totalSize = 5;
+        String indexUUID = "syzhajds-ashdlfj";
+        String remoteStoreRepository = "test-rs-repository";
+        String repositoryBasePath = "test-repo-basepath";
+        List<String> fileNames = new ArrayList<>(5);
+        fileNames.addAll(Arrays.asList("file1", "file2", "file3", "file4", "file5"));
+        RemoteStoreShardShallowCopySnapshot expectedShardShallowCopySnapshot = new RemoteStoreShardShallowCopySnapshot(
+            snapshot,
+            indexVersion,
+            primaryTerm,
+            commitGeneration,
+            startTime,
+            time,
+            totalFileCount,
+            totalSize,
+            indexUUID,
+            remoteStoreRepository,
+            repositoryBasePath,
+            fileNames
+        );
+        String xContent = "{\"version\":\"1\",\"name\":\"test-snapshot\",\"index_version\":1,\"start_time\":123,\"time\":123,"
+            + "\"number_of_files\":5,\"total_size\":5,\"index_uuid\":\"syzhajds-ashdlfj\",\"remote_store_repository\":"
+            + "\"test-rs-repository\",\"commit_generation\":5,\"primary_term\":3,\"remote_store_repository_base_path\":"
+            + "\"test-repo-basepath\",\"file_names\":[\"file1\",\"file2\",\"file3\",\"file4\",\"file5\"]}";
+        try (XContentParser parser = createParser(JsonXContent.jsonXContent, xContent)) {
+            RemoteStoreShardShallowCopySnapshot actualShardShallowCopySnapshot = RemoteStoreShardShallowCopySnapshot.fromXContent(parser);
+            assertEquals(actualShardShallowCopySnapshot.snapshot(), expectedShardShallowCopySnapshot.snapshot());
+            assertEquals(
+                actualShardShallowCopySnapshot.getRemoteStoreRepository(),
+                expectedShardShallowCopySnapshot.getRemoteStoreRepository()
+            );
+            assertEquals(actualShardShallowCopySnapshot.getCommitGeneration(), expectedShardShallowCopySnapshot.getCommitGeneration());
+            assertEquals(actualShardShallowCopySnapshot.getPrimaryTerm(), expectedShardShallowCopySnapshot.getPrimaryTerm());
+            assertEquals(actualShardShallowCopySnapshot.startTime(), expectedShardShallowCopySnapshot.startTime());
+            assertEquals(actualShardShallowCopySnapshot.time(), expectedShardShallowCopySnapshot.time());
+            assertEquals(actualShardShallowCopySnapshot.totalSize(), expectedShardShallowCopySnapshot.totalSize());
+            assertEquals(actualShardShallowCopySnapshot.totalFileCount(), expectedShardShallowCopySnapshot.totalFileCount());
+        }
+    }
+
+    public void testFromXContentInvalid() throws IOException {
+        final int iters = scaledRandomIntBetween(1, 10);
+        for (int iter = 0; iter < iters; iter++) {
+            String snapshot = "test-snapshot";
+            long indexVersion = 1;
+            long primaryTerm = 3;
+            long commitGeneration = 5;
+            long startTime = 123;
+            long time = 123;
+            int totalFileCount = 5;
+            long totalSize = 5;
+            String indexUUID = "syzhajds-ashdlfj";
+            String remoteStoreRepository = "test-rs-repository";
+            String repositoryBasePath = "test-repo-basepath";
+            List<String> fileNames = new ArrayList<>(5);
+            fileNames.addAll(Arrays.asList("file1", "file2", "file3", "file4", "file5"));
+            String failure = null;
+            String version = RemoteStoreShardShallowCopySnapshot.DEFAULT_VERSION;
+            long length = Math.max(0, Math.abs(randomLong()));
+            // random corruption
+            switch (randomIntBetween(0, 8)) {
+                case 0:
+                    snapshot = null;
+                    failure = "Invalid/Missing Snapshot Name";
+                    break;
+                case 1:
+                    indexVersion = -Math.abs(randomLong());
+                    failure = "Invalid Index Version";
+                    break;
+                case 2:
+                    commitGeneration = -Math.abs(randomLong());
+                    failure = "Invalid Commit Generation";
+                    break;
+                case 3:
+                    primaryTerm = -Math.abs(randomLong());
+                    failure = "Invalid Primary Term";
+                    break;
+                case 4:
+                    indexUUID = null;
+                    failure = "Invalid/Missing Index UUID";
+                    break;
+                case 5:
+                    remoteStoreRepository = null;
+                    failure = "Invalid/Missing Remote Store Repository";
+                    break;
+                case 6:
+                    repositoryBasePath = null;
+                    failure = "Invalid/Missing Repository Base Path";
+                    break;
+                case 7:
+                    version = null;
+                    failure = "Invalid Version Provided";
+                    break;
+                case 8:
+                    break;
+                default:
+                    fail("shouldn't be here");
+            }
+
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+            builder.startObject();
+            builder.field(RemoteStoreShardShallowCopySnapshot.VERSION, version);
+            builder.field(RemoteStoreShardShallowCopySnapshot.NAME, snapshot);
+            builder.field(RemoteStoreShardShallowCopySnapshot.INDEX_VERSION, indexVersion);
+            builder.field(RemoteStoreShardShallowCopySnapshot.START_TIME, startTime);
+            builder.field(RemoteStoreShardShallowCopySnapshot.TIME, time);
+            builder.field(RemoteStoreShardShallowCopySnapshot.TOTAL_FILE_COUNT, totalFileCount);
+            builder.field(RemoteStoreShardShallowCopySnapshot.TOTAL_SIZE, totalSize);
+            builder.field(RemoteStoreShardShallowCopySnapshot.INDEX_UUID, indexUUID);
+            builder.field(RemoteStoreShardShallowCopySnapshot.REMOTE_STORE_REPOSITORY, remoteStoreRepository);
+            builder.field(RemoteStoreShardShallowCopySnapshot.COMMIT_GENERATION, commitGeneration);
+            builder.field(RemoteStoreShardShallowCopySnapshot.PRIMARY_TERM, primaryTerm);
+            builder.field(RemoteStoreShardShallowCopySnapshot.REPOSITORY_BASE_PATH, repositoryBasePath);
+            builder.startArray(RemoteStoreShardShallowCopySnapshot.FILE_NAMES);
+            for (String fileName : fileNames) {
+                builder.value(fileName);
+            }
+            builder.endArray();
+            builder.endObject();
+            byte[] xContent = BytesReference.toBytes(BytesReference.bytes(builder));
+
+            if (failure == null) {
+                // No failures should read as usual
+                final RemoteStoreShardShallowCopySnapshot remoteStoreShardShallowCopySnapshot;
+                try (XContentParser parser = createParser(JsonXContent.jsonXContent, xContent)) {
+                    parser.nextToken();
+                    remoteStoreShardShallowCopySnapshot = RemoteStoreShardShallowCopySnapshot.fromXContent(parser);
+                }
+                assertEquals(remoteStoreShardShallowCopySnapshot.snapshot(), snapshot);
+                assertEquals(remoteStoreShardShallowCopySnapshot.getRemoteStoreRepository(), remoteStoreRepository);
+                assertEquals(remoteStoreShardShallowCopySnapshot.getCommitGeneration(), commitGeneration);
+                assertEquals(remoteStoreShardShallowCopySnapshot.getPrimaryTerm(), primaryTerm);
+                assertEquals(remoteStoreShardShallowCopySnapshot.startTime(), startTime);
+                assertEquals(remoteStoreShardShallowCopySnapshot.time(), time);
+                assertEquals(remoteStoreShardShallowCopySnapshot.totalSize(), totalSize);
+                assertEquals(remoteStoreShardShallowCopySnapshot.totalFileCount(), totalFileCount);
+            } else {
+                try (XContentParser parser = createParser(JsonXContent.jsonXContent, xContent)) {
+                    parser.nextToken();
+                    RemoteStoreShardShallowCopySnapshot.fromXContent(parser);
+                    fail("Should have failed with [" + failure + "]");
+                } catch (IllegalArgumentException ex) {
+                    assertThat(ex.getMessage(), containsString(failure));
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/snapshots/blobstore/SlicedInputStreamTests.java b/server/src/test/java/org/opensearch/index/snapshots/blobstore/SlicedInputStreamTests.java
index 3e337bbe3adae..bf269e3951a74 100644
--- a/server/src/test/java/org/opensearch/index/snapshots/blobstore/SlicedInputStreamTests.java
+++ b/server/src/test/java/org/opensearch/index/snapshots/blobstore/SlicedInputStreamTests.java
@@ -32,13 +32,18 @@
 package org.opensearch.index.snapshots.blobstore;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.MatcherAssert;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Random;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -86,11 +91,9 @@ protected InputStream openSlice(int slice) throws IOException {
                     assertThat(random.nextInt(Byte.MAX_VALUE), equalTo(input.read()));
                     break;
                 default:
-                    byte[] b = randomBytes(random);
-                    byte[] buffer = new byte[b.length];
-                    int read = readFully(input, buffer);
-                    assertThat(b.length, equalTo(read));
-                    assertArrayEquals(b, buffer);
+                    byte[] expectedBytes = randomBytes(random);
+                    byte[] actualBytes = input.readNBytes(expectedBytes.length);
+                    assertArrayEquals(expectedBytes, actualBytes);
                     break;
             }
         }
@@ -107,19 +110,45 @@ protected InputStream openSlice(int slice) throws IOException {
 
     }
 
-    private int readFully(InputStream stream, byte[] buffer) throws IOException {
-        for (int i = 0; i < buffer.length;) {
-            int read = stream.read(buffer, i, buffer.length - i);
-            if (read == -1) {
-                if (i == 0) {
-                    return -1;
-                } else {
-                    return i;
-                }
+    public void testReadZeroLength() throws IOException {
+        try (InputStream input = createSingleByteStream()) {
+            final byte[] buffer = new byte[100];
+            final int read = input.read(buffer, 0, 0);
+            MatcherAssert.assertThat(read, equalTo(0));
+        }
+    }
+
+    public void testInvalidOffsetAndLength() throws IOException {
+        try (InputStream input = createSingleByteStream()) {
+            final byte[] buffer = new byte[100];
+            expectThrows(NullPointerException.class, () -> input.read(null, 0, 10));
+            expectThrows(IndexOutOfBoundsException.class, () -> input.read(buffer, -1, 10));
+            expectThrows(IndexOutOfBoundsException.class, () -> input.read(buffer, 0, -1));
+            expectThrows(IndexOutOfBoundsException.class, () -> input.read(buffer, 0, buffer.length + 1));
+        }
+    }
+
+    public void testReadAllBytes() throws IOException {
+        final byte[] expectedResults = randomByteArrayOfLength(50_000);
+        final int numSlices = 200;
+        final int slizeSize = expectedResults.length / numSlices;
+
+        final List<byte[]> arraySlices = new ArrayList<>(numSlices);
+        for (int i = 0; i < numSlices; i++) {
+            final int offset = slizeSize * i;
+            arraySlices.add(Arrays.copyOfRange(expectedResults, offset, offset + slizeSize));
+        }
+        // Create a SlicedInputStream that will return the expected result in 2 slices
+        final byte[] actualResults;
+        try (InputStream is = new SlicedInputStream(numSlices) {
+            @Override
+            protected InputStream openSlice(int slice) {
+                return new ByteArrayInputStream(arraySlices.get(slice));
             }
-            i += read;
+        }) {
+            actualResults = is.readAllBytes();
         }
-        return buffer.length;
+        assertArrayEquals(expectedResults, actualResults);
     }
 
     private byte[] randomBytes(Random random) {
@@ -129,6 +158,15 @@ private byte[] randomBytes(Random random) {
         return data;
     }
 
+    private static InputStream createSingleByteStream() {
+        return new SlicedInputStream(1) {
+            @Override
+            protected InputStream openSlice(int slice) {
+                return new ByteArrayInputStream(new byte[] { 1 });
+            }
+        };
+    }
+
     private static final class CheckClosedInputStream extends FilterInputStream {
 
         public boolean closed = false;
diff --git a/server/src/test/java/org/opensearch/index/store/FsDirectoryFactoryTests.java b/server/src/test/java/org/opensearch/index/store/FsDirectoryFactoryTests.java
index 70d4ae790f146..2fffebbcf5f1f 100644
--- a/server/src/test/java/org/opensearch/index/store/FsDirectoryFactoryTests.java
+++ b/server/src/test/java/org/opensearch/index/store/FsDirectoryFactoryTests.java
@@ -42,13 +42,13 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -57,6 +57,8 @@
 import java.util.Arrays;
 import java.util.Locale;
 
+import static org.opensearch.test.store.MockFSDirectoryFactory.FILE_SYSTEM_BASED_STORE_TYPES;
+
 public class FsDirectoryFactoryTests extends OpenSearchTestCase {
 
     public void testPreload() throws IOException {
@@ -70,20 +72,149 @@ public void testPreload() throws IOException {
         try (Directory directory = newDirectory(build)) {
             assertTrue(FsDirectoryFactory.isHybridFs(directory));
             FsDirectoryFactory.HybridDirectory hybridDirectory = (FsDirectoryFactory.HybridDirectory) directory;
-            assertTrue(hybridDirectory.useDelegate("foo.dvd"));
+            // test default hybrid extensions
+            // true->mmap, false->nio
             assertTrue(hybridDirectory.useDelegate("foo.nvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.dvd"));
             assertTrue(hybridDirectory.useDelegate("foo.tim"));
             assertTrue(hybridDirectory.useDelegate("foo.tip"));
-            assertTrue(hybridDirectory.useDelegate("foo.cfs"));
             assertTrue(hybridDirectory.useDelegate("foo.dim"));
             assertTrue(hybridDirectory.useDelegate("foo.kdd"));
             assertTrue(hybridDirectory.useDelegate("foo.kdi"));
-            assertFalse(hybridDirectory.useDelegate("foo.bar"));
+            assertTrue(hybridDirectory.useDelegate("foo.cfs"));
+            assertTrue(hybridDirectory.useDelegate("foo.doc"));
+            assertTrue(hybridDirectory.useDelegate("foo.new"));
+            assertFalse(hybridDirectory.useDelegate("foo.pos"));
+            assertFalse(hybridDirectory.useDelegate("foo.pay"));
             MMapDirectory delegate = hybridDirectory.getDelegate();
             assertThat(delegate, Matchers.instanceOf(FsDirectoryFactory.PreLoadMMapDirectory.class));
             FsDirectoryFactory.PreLoadMMapDirectory preLoadMMapDirectory = (FsDirectoryFactory.PreLoadMMapDirectory) delegate;
             assertTrue(preLoadMMapDirectory.useDelegate("foo.dvd"));
             assertTrue(preLoadMMapDirectory.useDelegate("foo.bar"));
+            assertFalse(preLoadMMapDirectory.useDelegate("foo.cfs"));
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey(), "tip", "dim", "kdd", "kdi", "cfs", "doc")
+            .build();
+        try (Directory directory = newDirectory(build)) {
+            assertTrue(FsDirectoryFactory.isHybridFs(directory));
+            FsDirectoryFactory.HybridDirectory hybridDirectory = (FsDirectoryFactory.HybridDirectory) directory;
+            // test custom hybrid nio extensions
+            // true->mmap, false->nio
+            assertTrue(hybridDirectory.useDelegate("foo.nvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.dvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.tim"));
+            assertTrue(hybridDirectory.useDelegate("foo.pos"));
+            assertTrue(hybridDirectory.useDelegate("foo.pay"));
+            assertTrue(hybridDirectory.useDelegate("foo.new"));
+            assertFalse(hybridDirectory.useDelegate("foo.tip"));
+            assertFalse(hybridDirectory.useDelegate("foo.dim"));
+            assertFalse(hybridDirectory.useDelegate("foo.kdd"));
+            assertFalse(hybridDirectory.useDelegate("foo.kdi"));
+            assertFalse(hybridDirectory.useDelegate("foo.cfs"));
+            assertFalse(hybridDirectory.useDelegate("foo.doc"));
+            MMapDirectory delegate = hybridDirectory.getDelegate();
+            assertThat(delegate, Matchers.instanceOf(FsDirectoryFactory.PreLoadMMapDirectory.class));
+            FsDirectoryFactory.PreLoadMMapDirectory preLoadMMapDirectory = (FsDirectoryFactory.PreLoadMMapDirectory) delegate;
+            assertTrue(preLoadMMapDirectory.useDelegate("foo.dvd"));
+            assertFalse(preLoadMMapDirectory.useDelegate("foo.bar"));
+            assertTrue(preLoadMMapDirectory.useDelegate("foo.cfs"));
+            assertTrue(preLoadMMapDirectory.useDelegate("foo.nvd"));
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey(), "nvd", "dvd", "tim", "pos")
+            .build();
+        try (Directory directory = newDirectory(build)) {
+            assertTrue(FsDirectoryFactory.isHybridFs(directory));
+            FsDirectoryFactory.HybridDirectory hybridDirectory = (FsDirectoryFactory.HybridDirectory) directory;
+            // test custom hybrid mmap extensions
+            // true->mmap, false->nio
+            assertTrue(hybridDirectory.useDelegate("foo.nvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.dvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.tim"));
+            assertTrue(hybridDirectory.useDelegate("foo.pos"));
+            assertTrue(hybridDirectory.useDelegate("foo.new"));
+            assertFalse(hybridDirectory.useDelegate("foo.pay"));
+            assertFalse(hybridDirectory.useDelegate("foo.tip"));
+            assertFalse(hybridDirectory.useDelegate("foo.dim"));
+            assertFalse(hybridDirectory.useDelegate("foo.kdd"));
+            assertFalse(hybridDirectory.useDelegate("foo.kdi"));
+            assertFalse(hybridDirectory.useDelegate("foo.cfs"));
+            assertFalse(hybridDirectory.useDelegate("foo.doc"));
+            MMapDirectory delegate = hybridDirectory.getDelegate();
+            assertThat(delegate, Matchers.instanceOf(FsDirectoryFactory.PreLoadMMapDirectory.class));
+            assertWarnings(
+                "[index.store.hybrid.mmap.extensions] setting was deprecated in OpenSearch and will be removed in a future release!"
+                    + " See the breaking changes documentation for the next major version."
+            );
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey(), "nvd", "dvd", "tim", "pos")
+            .putList(IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey(), "nvd", "dvd", "tim", "pos")
+            .build();
+        try {
+            newDirectory(build);
+        } catch (final Exception e) {
+            assertEquals(
+                "Settings index.store.hybrid.nio.extensions & index.store.hybrid.mmap.extensions cannot both be set. Use index.store.hybrid.nio.extensions only.",
+                e.getMessage()
+            );
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey(), "nvd", "dvd", "tim", "pos")
+            .putList(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey(), "nvd", "dvd", "tim", "pos")
+            .build();
+        try {
+            newDirectory(build);
+        } catch (final Exception e) {
+            assertEquals(
+                "Settings index.store.hybrid.nio.extensions & index.store.hybrid.mmap.extensions cannot both be set. Use index.store.hybrid.nio.extensions only.",
+                e.getMessage()
+            );
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_NIO_EXTENSIONS.getKey())
+            .build();
+        try (Directory directory = newDirectory(build)) {
+            assertTrue(FsDirectoryFactory.isHybridFs(directory));
+            FsDirectoryFactory.HybridDirectory hybridDirectory = (FsDirectoryFactory.HybridDirectory) directory;
+            // test custom hybrid mmap extensions
+            // true->mmap, false->nio
+            assertTrue(hybridDirectory.useDelegate("foo.new"));
+            assertTrue(hybridDirectory.useDelegate("foo.nvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.dvd"));
+            assertTrue(hybridDirectory.useDelegate("foo.cfs"));
+            assertTrue(hybridDirectory.useDelegate("foo.doc"));
+            MMapDirectory delegate = hybridDirectory.getDelegate();
+            assertThat(delegate, Matchers.instanceOf(FsDirectoryFactory.PreLoadMMapDirectory.class));
+        }
+        build = Settings.builder()
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.HYBRIDFS.name().toLowerCase(Locale.ROOT))
+            .putList(IndexModule.INDEX_STORE_PRE_LOAD_SETTING.getKey(), "nvd", "dvd", "cfs")
+            .putList(IndexModule.INDEX_STORE_HYBRID_MMAP_EXTENSIONS.getKey())
+            .build();
+        try (Directory directory = newDirectory(build)) {
+            assertTrue(FsDirectoryFactory.isHybridFs(directory));
+            FsDirectoryFactory.HybridDirectory hybridDirectory = (FsDirectoryFactory.HybridDirectory) directory;
+            // test custom hybrid mmap extensions
+            // true->mmap, false->nio
+            assertTrue(hybridDirectory.useDelegate("foo.new"));
+            assertFalse(hybridDirectory.useDelegate("foo.nvd"));
+            assertFalse(hybridDirectory.useDelegate("foo.dvd"));
+            assertFalse(hybridDirectory.useDelegate("foo.cfs"));
+            assertFalse(hybridDirectory.useDelegate("foo.doc"));
+            MMapDirectory delegate = hybridDirectory.getDelegate();
+            assertThat(delegate, Matchers.instanceOf(FsDirectoryFactory.PreLoadMMapDirectory.class));
         }
     }
 
@@ -138,7 +269,7 @@ public void testStoreDirectory() throws IOException {
         // default
         doTestStoreDirectory(tempDir, null, IndexModule.Type.FS);
         // explicit directory impls
-        for (IndexModule.Type type : IndexModule.Type.values()) {
+        for (IndexModule.Type type : FILE_SYSTEM_BASED_STORE_TYPES) {
             doTestStoreDirectory(tempDir, type.name().toLowerCase(Locale.ROOT), type);
         }
     }
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteBufferedIndexOutputTests.java b/server/src/test/java/org/opensearch/index/store/RemoteBufferedIndexOutputTests.java
new file mode 100644
index 0000000000000..b2d2809e12972
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteBufferedIndexOutputTests.java
@@ -0,0 +1,163 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyLong;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteBufferedIndexOutputTests extends OpenSearchTestCase {
+
+    private static final String FILENAME = "segment_1";
+
+    private BlobContainer blobContainer;
+
+    private BytesStreamOutput out;
+
+    private OutputStreamIndexOutput indexOutputBuffer;
+
+    private RemoteBufferedIndexOutput remoteBufferedIndexOutput;
+
+    @Before
+    public void setup() {
+        blobContainer = mock(BlobContainer.class);
+        out = new BytesStreamOutput();
+        indexOutputBuffer = new OutputStreamIndexOutput(FILENAME, FILENAME, out, RemoteBufferedIndexOutput.BUFFER_SIZE);
+        remoteBufferedIndexOutput = new RemoteBufferedIndexOutput(FILENAME, blobContainer, out, indexOutputBuffer);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        try (final BytesStreamOutput outStream = out) {
+            indexOutputBuffer.close();
+        } catch (IOException e) {
+            // do nothing
+        }
+    }
+
+    public void testCopyBytes() throws IOException {
+        String testData = "testData";
+        IndexInput indexInput = new ByteArrayIndexInput("blobName", testData.getBytes(StandardCharsets.UTF_8));
+        remoteBufferedIndexOutput.copyBytes(indexInput, indexInput.length());
+        indexOutputBuffer.getChecksum(); // calling getChecksum() to flush the buffer.
+        assertEquals(out.bytes().utf8ToString(), testData);
+        out.reset();
+    }
+
+    public void testCopyBytesException() throws IOException {
+        OutputStreamIndexOutput indexOutputBufferMock = mock(OutputStreamIndexOutput.class);
+        IndexInput indexInput = mock(IndexInput.class);
+        RemoteBufferedIndexOutput bufferedIndexOutputUsingMock = new RemoteBufferedIndexOutput(
+            FILENAME,
+            blobContainer,
+            out,
+            indexOutputBufferMock
+        );
+        doThrow(new IOException("Test Induced Failure")).when(indexOutputBufferMock).copyBytes(eq(indexInput), eq(100L));
+
+        assertThrows(IOException.class, () -> bufferedIndexOutputUsingMock.copyBytes(indexInput, 100));
+    }
+
+    public void testWriteBytes() throws IOException {
+        byte[] b = new byte[] { Byte.MAX_VALUE };
+        remoteBufferedIndexOutput.writeBytes(b, 0, b.length);
+        indexOutputBuffer.getChecksum(); // calling getChecksum() to flush the buffer.
+        assertArrayEquals(b, BytesReference.toBytes(out.bytes()));
+        out.reset();
+    }
+
+    public void testClose() throws IOException {
+        BytesReference mockBytesReference = mock(BytesReference.class);
+        BytesStreamOutput outStream = mock(BytesStreamOutput.class);
+        when(outStream.bytes()).thenReturn(mockBytesReference);
+        when(mockBytesReference.streamInput()).thenReturn(mock(StreamInput.class));
+
+        OutputStreamIndexOutput indexOutputBufferMock = mock(OutputStreamIndexOutput.class);
+        RemoteBufferedIndexOutput bufferedIndexOutputUsingMock = new RemoteBufferedIndexOutput(
+            FILENAME,
+            blobContainer,
+            outStream,
+            indexOutputBufferMock
+        );
+
+        bufferedIndexOutputUsingMock.close();
+        verify(blobContainer).writeBlob(eq(FILENAME), any(StreamInput.class), anyLong(), eq(false));
+        verify(indexOutputBufferMock).close();
+        verify(outStream).close();
+    }
+
+    public void testCloseException() throws IOException {
+        BytesReference mockBytesReference = mock(BytesReference.class);
+        BytesStreamOutput outStream = mock(BytesStreamOutput.class);
+        when(outStream.bytes()).thenReturn(mockBytesReference);
+        StreamInput streamInputMock = mock(StreamInput.class);
+        when(mockBytesReference.streamInput()).thenReturn(streamInputMock);
+        doThrow(new IOException("Test Induced Failure")).when(streamInputMock).close();
+
+        OutputStreamIndexOutput indexOutputBufferMock = mock(OutputStreamIndexOutput.class);
+        RemoteBufferedIndexOutput bufferedIndexOutputUsingMock = new RemoteBufferedIndexOutput(
+            FILENAME,
+            blobContainer,
+            outStream,
+            indexOutputBufferMock
+        );
+        try {
+            bufferedIndexOutputUsingMock.close();
+        } catch (Exception e) {
+            // do nothing
+        }
+        verify(blobContainer).writeBlob(eq(FILENAME), any(StreamInput.class), anyLong(), eq(false));
+        verify(indexOutputBufferMock).close();
+        verify(outStream).close();
+
+    }
+
+    public void testCloseException2() throws IOException {
+        BytesReference mockBytesReference = mock(BytesReference.class);
+        BytesStreamOutput outStream = mock(BytesStreamOutput.class);
+        when(outStream.bytes()).thenReturn(mockBytesReference);
+        StreamInput streamInputMock = mock(StreamInput.class);
+        when(mockBytesReference.streamInput()).thenReturn(streamInputMock);
+
+        OutputStreamIndexOutput indexOutputBufferMock = mock(OutputStreamIndexOutput.class);
+        doThrow(new IOException("Test Induced Failure")).when(indexOutputBufferMock).close();
+        RemoteBufferedIndexOutput bufferedIndexOutputUsingMock = new RemoteBufferedIndexOutput(
+            FILENAME,
+            blobContainer,
+            outStream,
+            indexOutputBufferMock
+        );
+        try {
+            bufferedIndexOutputUsingMock.close();
+        } catch (Exception e) {
+            // do nothing
+        }
+        verify(indexOutputBufferMock).close();
+        verify(outStream).close();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteBufferedOutputDirectoryTests.java b/server/src/test/java/org/opensearch/index/store/RemoteBufferedOutputDirectoryTests.java
new file mode 100644
index 0000000000000..0595bb0001640
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteBufferedOutputDirectoryTests.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.IOContext;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import static org.mockito.Mockito.mock;
+
+public class RemoteBufferedOutputDirectoryTests extends OpenSearchTestCase {
+
+    private BlobContainer blobContainer;
+    private RemoteBufferedOutputDirectory remoteBufferedOutputDirectory;
+
+    @Before
+    public void setup() {
+        blobContainer = mock(BlobContainer.class);
+        remoteBufferedOutputDirectory = new RemoteBufferedOutputDirectory(blobContainer);
+    }
+
+    public void testCreateOutput() {
+        String testBlobName = "testBlob";
+        assert (remoteBufferedOutputDirectory.createOutput(testBlobName, IOContext.DEFAULT) instanceof RemoteBufferedIndexOutput);
+
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteDirectoryTests.java b/server/src/test/java/org/opensearch/index/store/RemoteDirectoryTests.java
new file mode 100644
index 0000000000000..3740abc57b02d
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteDirectoryTests.java
@@ -0,0 +1,311 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.support.PlainBlobMetadata;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.NoSuchFileException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteDirectoryTests extends OpenSearchTestCase {
+    private BlobContainer blobContainer;
+
+    private RemoteDirectory remoteDirectory;
+
+    @Before
+    public void setup() {
+        blobContainer = mock(BlobContainer.class);
+        remoteDirectory = new RemoteDirectory(blobContainer);
+    }
+
+    public void testListAllEmpty() throws IOException {
+        when(blobContainer.listBlobs()).thenReturn(Collections.emptyMap());
+
+        String[] actualFileNames = remoteDirectory.listAll();
+        String[] expectedFileName = new String[] {};
+        assertArrayEquals(expectedFileName, actualFileNames);
+    }
+
+    public void testCopyFrom() throws IOException, InterruptedException {
+        AtomicReference<Boolean> postUploadInvoked = new AtomicReference<>(false);
+        String filename = "_100.si";
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onResponse(null);
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+        IndexOutput indexOutput = storeDirectory.createOutput(filename, IOContext.DEFAULT);
+        indexOutput.writeString("Hello World!");
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        storeDirectory.sync(List.of(filename));
+
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        RemoteDirectory remoteDirectory = new RemoteDirectory(blobContainer);
+        remoteDirectory.copyFrom(
+            storeDirectory,
+            filename,
+            filename,
+            IOContext.READ,
+            () -> postUploadInvoked.set(true),
+            new ActionListener<>() {
+                @Override
+                public void onResponse(Void t) {
+                    countDownLatch.countDown();
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    fail("Listener responded with exception" + e);
+                }
+            }
+        );
+        assertTrue(countDownLatch.await(10, TimeUnit.SECONDS));
+        assertTrue(postUploadInvoked.get());
+        storeDirectory.close();
+    }
+
+    public void testCopyFromWithException() throws IOException, InterruptedException {
+        AtomicReference<Boolean> postUploadInvoked = new AtomicReference<>(false);
+        String filename = "_100.si";
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onResponse(null);
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+        RemoteDirectory remoteDirectory = new RemoteDirectory(blobContainer);
+        remoteDirectory.copyFrom(
+            storeDirectory,
+            filename,
+            filename,
+            IOContext.READ,
+            () -> postUploadInvoked.set(true),
+            new ActionListener<>() {
+                @Override
+                public void onResponse(Void t) {
+                    fail("Listener responded with success");
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    countDownLatch.countDown();
+                }
+            }
+        );
+        assertTrue(countDownLatch.await(10, TimeUnit.SECONDS));
+        assertFalse(postUploadInvoked.get());
+        storeDirectory.close();
+    }
+
+    public void testListAll() throws IOException {
+        Map<String, BlobMetadata> fileNames = Stream.of("abc", "xyz", "pqr", "lmn", "jkl")
+            .collect(Collectors.toMap(filename -> filename, filename -> new PlainBlobMetadata(filename, 100)));
+
+        when(blobContainer.listBlobs()).thenReturn(fileNames);
+
+        String[] actualFileNames = remoteDirectory.listAll();
+        String[] expectedFileName = new String[] { "abc", "jkl", "lmn", "pqr", "xyz" };
+        assertArrayEquals(expectedFileName, actualFileNames);
+    }
+
+    public void testListAllException() throws IOException {
+        when(blobContainer.listBlobs()).thenThrow(new IOException("Error reading blob store"));
+
+        assertThrows(IOException.class, () -> remoteDirectory.listAll());
+    }
+
+    public void testListFilesByPrefix() throws IOException {
+        Map<String, BlobMetadata> fileNames = Stream.of("abc", "abd", "abe", "abf", "abg")
+            .collect(Collectors.toMap(filename -> filename, filename -> new PlainBlobMetadata(filename, 100)));
+
+        when(blobContainer.listBlobsByPrefix("ab")).thenReturn(fileNames);
+
+        Collection<String> actualFileNames = remoteDirectory.listFilesByPrefix("ab");
+        Collection<String> expectedFileName = Set.of("abc", "abd", "abe", "abf", "abg");
+        assertEquals(expectedFileName, actualFileNames);
+    }
+
+    public void testListFilesByPrefixException() throws IOException {
+        when(blobContainer.listBlobsByPrefix("abc")).thenThrow(new IOException("Error reading blob store"));
+
+        assertThrows(IOException.class, () -> remoteDirectory.listFilesByPrefix("abc"));
+        verify(blobContainer).listBlobsByPrefix("abc");
+    }
+
+    public void testDeleteFile() throws IOException {
+        remoteDirectory.deleteFile("segment_1");
+
+        verify(blobContainer).deleteBlobsIgnoringIfNotExists(Collections.singletonList("segment_1"));
+    }
+
+    public void testDeleteFileException() throws IOException {
+        doThrow(new IOException("Error writing to blob store")).when(blobContainer)
+            .deleteBlobsIgnoringIfNotExists(Collections.singletonList("segment_1"));
+
+        assertThrows(IOException.class, () -> remoteDirectory.deleteFile("segment_1"));
+    }
+
+    public void testCreateOutput() {
+        IndexOutput indexOutput = remoteDirectory.createOutput("segment_1", IOContext.DEFAULT);
+        assertTrue(indexOutput instanceof RemoteIndexOutput);
+        assertEquals("segment_1", indexOutput.getName());
+    }
+
+    public void testOpenInput() throws IOException {
+        InputStream mockInputStream = mock(InputStream.class);
+        when(blobContainer.readBlob("segment_1")).thenReturn(mockInputStream);
+        Map<String, BlobMetadata> fileInfo = new HashMap<>();
+        fileInfo.put("segment_1", new PlainBlobMetadata("segment_1", 100));
+        when(blobContainer.listBlobsByPrefix("segment_1")).thenReturn(fileInfo);
+
+        IndexInput indexInput = remoteDirectory.openInput("segment_1", IOContext.DEFAULT);
+        assertTrue(indexInput instanceof RemoteIndexInput);
+        assertEquals(100, indexInput.length());
+    }
+
+    public void testOpenInputIOException() throws IOException {
+        when(blobContainer.readBlob("segment_1")).thenThrow(new IOException("Error while reading"));
+
+        assertThrows(IOException.class, () -> remoteDirectory.openInput("segment_1", IOContext.DEFAULT));
+    }
+
+    public void testOpenInputNoSuchFileException() throws IOException {
+        InputStream mockInputStream = mock(InputStream.class);
+        when(blobContainer.readBlob("segment_1")).thenReturn(mockInputStream);
+        when(blobContainer.listBlobsByPrefix("segment_1")).thenThrow(new NoSuchFileException("segment_1"));
+
+        assertThrows(NoSuchFileException.class, () -> remoteDirectory.openInput("segment_1", IOContext.DEFAULT));
+    }
+
+    public void testFileLength() throws IOException {
+        Map<String, BlobMetadata> fileInfo = new HashMap<>();
+        fileInfo.put("segment_1", new PlainBlobMetadata("segment_1", 100));
+        when(blobContainer.listBlobsByPrefix("segment_1")).thenReturn(fileInfo);
+
+        assertEquals(100, remoteDirectory.fileLength("segment_1"));
+    }
+
+    public void testFileLengthIOException() throws IOException {
+        when(blobContainer.listBlobsByPrefix("segment_1")).thenThrow(new NoSuchFileException("segment_1"));
+
+        assertThrows(IOException.class, () -> remoteDirectory.fileLength("segment_1"));
+    }
+
+    public void testListFilesByPrefixInLexicographicOrder() throws IOException {
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            latchedActionListener.onResponse(List.of(new PlainBlobMetadata("metadata_1", 1)));
+            return null;
+        }).when(blobContainer)
+            .listBlobsByPrefixInSortedOrder(
+                eq("metadata"),
+                eq(1),
+                eq(BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC),
+                any(ActionListener.class)
+            );
+
+        assertEquals(List.of("metadata_1"), remoteDirectory.listFilesByPrefixInLexicographicOrder("metadata", 1));
+    }
+
+    public void testListFilesByPrefixInLexicographicOrderEmpty() throws IOException {
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            latchedActionListener.onResponse(List.of());
+            return null;
+        }).when(blobContainer)
+            .listBlobsByPrefixInSortedOrder(
+                eq("metadata"),
+                eq(1),
+                eq(BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC),
+                any(ActionListener.class)
+            );
+
+        assertEquals(List.of(), remoteDirectory.listFilesByPrefixInLexicographicOrder("metadata", 1));
+    }
+
+    public void testListFilesByPrefixInLexicographicOrderException() {
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            latchedActionListener.onFailure(new IOException("Error"));
+            return null;
+        }).when(blobContainer)
+            .listBlobsByPrefixInSortedOrder(
+                eq("metadata"),
+                eq(1),
+                eq(BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC),
+                any(ActionListener.class)
+            );
+
+        assertThrows(IOException.class, () -> remoteDirectory.listFilesByPrefixInLexicographicOrder("metadata", 1));
+    }
+
+    public void testGetPendingDeletions() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteDirectory.getPendingDeletions());
+    }
+
+    public void testCreateTempOutput() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteDirectory.createTempOutput("segment_1", "tmp", IOContext.DEFAULT));
+    }
+
+    public void testSync() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteDirectory.sync(Collections.emptyList()));
+    }
+
+    public void testRename() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteDirectory.rename("segment_1", "segment_2"));
+    }
+
+    public void testObtainLock() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteDirectory.obtainLock("segment_1"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteIndexInputTests.java b/server/src/test/java/org/opensearch/index/store/RemoteIndexInputTests.java
new file mode 100644
index 0000000000000..16f983253d058
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteIndexInputTests.java
@@ -0,0 +1,118 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteIndexInputTests extends OpenSearchTestCase {
+
+    private static final String FILENAME = "segment_1";
+    private static final long FILESIZE = 200;
+
+    private InputStream inputStream;
+    private RemoteIndexInput remoteIndexInput;
+
+    @Before
+    public void setup() {
+        inputStream = mock(InputStream.class);
+        remoteIndexInput = new RemoteIndexInput(FILENAME, inputStream, FILESIZE);
+    }
+
+    public void testReadByte() throws IOException {
+        InputStream inputStream = spy(InputStream.class);
+        remoteIndexInput = new RemoteIndexInput(FILENAME, inputStream, FILESIZE);
+
+        when(inputStream.read()).thenReturn(10);
+
+        assertEquals(10, remoteIndexInput.readByte());
+        assertEquals(1, remoteIndexInput.getFilePointer());
+
+        verify(inputStream).read(any());
+    }
+
+    public void testReadByteIOException() throws IOException {
+        when(inputStream.read(any())).thenThrow(new IOException("Error reading"));
+
+        assertThrows(IOException.class, () -> remoteIndexInput.readByte());
+        assertEquals(0, remoteIndexInput.getFilePointer());
+    }
+
+    public void testReadBytes() throws IOException {
+        byte[] buffer = new byte[20];
+        when(inputStream.read(eq(buffer), anyInt(), anyInt())).thenReturn(10).thenReturn(3).thenReturn(6).thenReturn(-1);
+        remoteIndexInput.readBytes(buffer, 0, 20);
+
+        verify(inputStream).read(buffer, 0, 20);
+        verify(inputStream).read(buffer, 10, 10);
+        verify(inputStream).read(buffer, 13, 7);
+        verify(inputStream).read(buffer, 19, 1);
+        assertEquals(19, remoteIndexInput.getFilePointer());
+    }
+
+    public void testReadBytesMultipleIterations() throws IOException {
+        byte[] buffer = new byte[20];
+        when(inputStream.read(eq(buffer), anyInt(), anyInt())).thenReturn(10).thenReturn(3).thenReturn(6).thenReturn(-1);
+        remoteIndexInput.readBytes(buffer, 0, 20);
+
+        verify(inputStream).read(buffer, 0, 20);
+        verify(inputStream).read(buffer, 10, 10);
+        verify(inputStream).read(buffer, 13, 7);
+        verify(inputStream).read(buffer, 19, 1);
+    }
+
+    public void testReadBytesIOException() throws IOException {
+        byte[] buffer = new byte[10];
+        when(inputStream.read(buffer, 10, 20)).thenThrow(new IOException("Error reading"));
+
+        assertThrows(IOException.class, () -> remoteIndexInput.readBytes(buffer, 10, 20));
+    }
+
+    public void testClose() throws IOException {
+        remoteIndexInput.close();
+
+        verify(inputStream).close();
+    }
+
+    public void testCloseIOException() throws IOException {
+        doThrow(new IOException("Error closing")).when(inputStream).close();
+
+        assertThrows(IOException.class, () -> remoteIndexInput.close());
+    }
+
+    public void testLength() {
+        assertEquals(FILESIZE, remoteIndexInput.length());
+    }
+
+    public void testSeek() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexInput.seek(100L));
+    }
+
+    public void testGetFilePointer() throws IOException {
+        when(inputStream.read(any(), eq(0), eq(8))).thenReturn(8);
+        remoteIndexInput.readBytes(new byte[8], 0, 8);
+        assertEquals(8, remoteIndexInput.getFilePointer());
+    }
+
+    public void testSlice() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexInput.slice("Slice middle", 50, 100));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteIndexOutputTests.java b/server/src/test/java/org/opensearch/index/store/RemoteIndexOutputTests.java
new file mode 100644
index 0000000000000..d440dfca24f84
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteIndexOutputTests.java
@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.lucene.store.InputStreamIndexInput;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+public class RemoteIndexOutputTests extends OpenSearchTestCase {
+    private static final String FILENAME = "segment_1";
+
+    private BlobContainer blobContainer;
+
+    private RemoteIndexOutput remoteIndexOutput;
+
+    @Before
+    public void setup() {
+        blobContainer = mock(BlobContainer.class);
+        remoteIndexOutput = new RemoteIndexOutput(FILENAME, blobContainer);
+    }
+
+    public void testCopyBytes() throws IOException {
+        IndexInput indexInput = mock(IndexInput.class);
+        remoteIndexOutput.copyBytes(indexInput, 100);
+
+        verify(blobContainer).writeBlob(eq(FILENAME), any(InputStreamIndexInput.class), eq(100L), eq(false));
+    }
+
+    public void testCopyBytesIOException() throws IOException {
+        doThrow(new IOException("Error writing")).when(blobContainer)
+            .writeBlob(eq(FILENAME), any(InputStreamIndexInput.class), eq(100L), eq(false));
+
+        IndexInput indexInput = mock(IndexInput.class);
+        assertThrows(IOException.class, () -> remoteIndexOutput.copyBytes(indexInput, 100));
+    }
+
+    public void testWriteByte() {
+        byte b = 10;
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexOutput.writeByte(b));
+    }
+
+    public void testWriteBytes() {
+        byte[] buffer = new byte[10];
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexOutput.writeBytes(buffer, 50, 60));
+    }
+
+    public void testGetFilePointer() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexOutput.getFilePointer());
+    }
+
+    public void testGetChecksum() {
+        assertThrows(UnsupportedOperationException.class, () -> remoteIndexOutput.getChecksum());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactoryTests.java b/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactoryTests.java
new file mode 100644
index 0000000000000..78c7fe64cebd9
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryFactoryTests.java
@@ -0,0 +1,128 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.lucene.store.Directory;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.function.Supplier;
+
+import org.mockito.ArgumentCaptor;
+
+import static org.opensearch.index.store.RemoteSegmentStoreDirectory.METADATA_FILES_TO_FETCH;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteSegmentStoreDirectoryFactoryTests extends OpenSearchTestCase {
+
+    private Supplier<RepositoriesService> repositoriesServiceSupplier;
+    private RepositoriesService repositoriesService;
+    private ThreadPool threadPool;
+    private RemoteSegmentStoreDirectoryFactory remoteSegmentStoreDirectoryFactory;
+
+    @Before
+    public void setup() {
+        repositoriesServiceSupplier = mock(Supplier.class);
+        repositoriesService = mock(RepositoriesService.class);
+        threadPool = mock(ThreadPool.class);
+        when(repositoriesServiceSupplier.get()).thenReturn(repositoriesService);
+        remoteSegmentStoreDirectoryFactory = new RemoteSegmentStoreDirectoryFactory(
+            repositoriesServiceSupplier,
+            threadPool,
+            DefaultRecoverySettings.INSTANCE
+        );
+    }
+
+    public void testNewDirectory() throws IOException {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_UUID, "uuid_1")
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "remote_store_repository")
+            .build();
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("foo", settings);
+        Path tempDir = createTempDir().resolve(indexSettings.getUUID()).resolve("0");
+        ShardPath shardPath = new ShardPath(false, tempDir, tempDir, new ShardId(indexSettings.getIndex(), 0));
+        BlobStoreRepository repository = mock(BlobStoreRepository.class);
+        BlobStore blobStore = mock(BlobStore.class);
+        BlobContainer blobContainer = mock(BlobContainer.class);
+        when(repository.blobStore()).thenReturn(blobStore);
+        when(repository.basePath()).thenReturn(new BlobPath().add("base_path"));
+        when(blobStore.blobContainer(any())).thenReturn(blobContainer);
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            latchedActionListener.onResponse(List.of());
+            return null;
+        }).when(blobContainer)
+            .listBlobsByPrefixInSortedOrder(
+                any(),
+                eq(METADATA_FILES_TO_FETCH),
+                eq(BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC),
+                any(ActionListener.class)
+            );
+
+        when(repositoriesService.repository("remote_store_repository")).thenReturn(repository);
+
+        try (Directory directory = remoteSegmentStoreDirectoryFactory.newDirectory(indexSettings, shardPath)) {
+            assertTrue(directory instanceof RemoteSegmentStoreDirectory);
+            ArgumentCaptor<BlobPath> blobPathCaptor = ArgumentCaptor.forClass(BlobPath.class);
+            verify(blobStore, times(3)).blobContainer(blobPathCaptor.capture());
+            List<BlobPath> blobPaths = blobPathCaptor.getAllValues();
+            assertEquals("base_path/uuid_1/0/segments/data/", blobPaths.get(0).buildAsString());
+            assertEquals("base_path/uuid_1/0/segments/metadata/", blobPaths.get(1).buildAsString());
+            assertEquals("base_path/uuid_1/0/segments/lock_files/", blobPaths.get(2).buildAsString());
+
+            verify(blobContainer).listBlobsByPrefixInSortedOrder(
+                eq(RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX),
+                eq(METADATA_FILES_TO_FETCH),
+                eq(BlobContainer.BlobNameSortOrder.LEXICOGRAPHIC),
+                any()
+            );
+            verify(repositoriesService, times(2)).repository("remote_store_repository");
+        }
+    }
+
+    public void testNewDirectoryRepositoryDoesNotExist() {
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "remote_store_repository")
+            .build();
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("foo", settings);
+        Path tempDir = createTempDir().resolve(indexSettings.getUUID()).resolve("0");
+        ShardPath shardPath = new ShardPath(false, tempDir, tempDir, new ShardId(indexSettings.getIndex(), 0));
+
+        when(repositoriesService.repository("remote_store_repository")).thenThrow(new RepositoryMissingException("Missing"));
+
+        assertThrows(IllegalArgumentException.class, () -> remoteSegmentStoreDirectoryFactory.newDirectory(indexSettings, shardPath));
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryTests.java b/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryTests.java
new file mode 100644
index 0000000000000..b574ccaac55e1
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/RemoteSegmentStoreDirectoryTests.java
@@ -0,0 +1,1226 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.IndexFormatTooNewException;
+import org.apache.lucene.index.IndexFormatTooOldException;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.apache.lucene.util.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.common.io.VersionedCodecStreamWrapper;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.lockmanager.RemoteStoreMetadataLockManager;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadataHandler;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.function.UnaryOperator;
+
+import org.mockito.Mockito;
+
+import static org.opensearch.index.store.RemoteSegmentStoreDirectory.METADATA_FILES_TO_FETCH;
+import static org.opensearch.test.RemoteStoreTestUtils.createMetadataFileBytes;
+import static org.opensearch.test.RemoteStoreTestUtils.getDummyMetadata;
+import static org.hamcrest.CoreMatchers.is;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.contains;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.startsWith;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteSegmentStoreDirectoryTests extends IndexShardTestCase {
+    private static final Logger logger = LogManager.getLogger(RemoteSegmentStoreDirectoryTests.class);
+    private RemoteDirectory remoteDataDirectory;
+    private RemoteDirectory remoteMetadataDirectory;
+    private RemoteStoreMetadataLockManager mdLockManager;
+
+    private RemoteSegmentStoreDirectory remoteSegmentStoreDirectory;
+    private TestUploadListener testUploadTracker;
+    private IndexShard indexShard;
+    private SegmentInfos segmentInfos;
+    private ThreadPool threadPool;
+
+    private final String metadataFilename = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        23,
+        34,
+        1,
+        1,
+        "node-1"
+    );
+
+    private final String metadataFilenameDup = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        23,
+        34,
+        2,
+        1,
+        "node-2"
+    );
+    private final String metadataFilename2 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        12,
+        13,
+        34,
+        1,
+        1,
+        "node-1"
+    );
+    private final String metadataFilename3 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(
+        10,
+        38,
+        34,
+        1,
+        1,
+        "node-1"
+    );
+
+    @Before
+    public void setup() throws IOException {
+        remoteDataDirectory = mock(RemoteDirectory.class);
+        remoteMetadataDirectory = mock(RemoteDirectory.class);
+        mdLockManager = mock(RemoteStoreMetadataLockManager.class);
+        threadPool = mock(ThreadPool.class);
+        testUploadTracker = new TestUploadListener();
+
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+        ExecutorService executorService = OpenSearchExecutors.newDirectExecutorService();
+
+        indexShard = newStartedShard(false, indexSettings, new NRTReplicationEngineFactory());
+        remoteSegmentStoreDirectory = new RemoteSegmentStoreDirectory(
+            remoteDataDirectory,
+            remoteMetadataDirectory,
+            mdLockManager,
+            threadPool,
+            indexShard.shardId(),
+            DefaultRecoverySettings.INSTANCE
+        );
+        try (Store store = indexShard.store()) {
+            segmentInfos = store.readLastCommittedSegmentsInfo();
+        }
+
+        when(remoteDataDirectory.getDownloadRateLimiter()).thenReturn(UnaryOperator.identity());
+        when(threadPool.executor(ThreadPool.Names.REMOTE_PURGE)).thenReturn(executorService);
+        when(threadPool.executor(ThreadPool.Names.REMOTE_RECOVERY)).thenReturn(executorService);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        indexShard.close("test tearDown", true, false);
+        super.tearDown();
+    }
+
+    public void testUploadedSegmentMetadataToString() {
+        RemoteSegmentStoreDirectory.UploadedSegmentMetadata metadata = new RemoteSegmentStoreDirectory.UploadedSegmentMetadata(
+            "abc",
+            "pqr",
+            "123456",
+            1234
+        );
+        metadata.setWrittenByMajor(Version.LATEST.major);
+        assertEquals("abc::pqr::123456::1234::" + Version.LATEST.major, metadata.toString());
+    }
+
+    public void testUploadedSegmentMetadataToStringExceptionTooNew() {
+        RemoteSegmentStoreDirectory.UploadedSegmentMetadata metadata = new RemoteSegmentStoreDirectory.UploadedSegmentMetadata(
+            "abc",
+            "pqr",
+            "123456",
+            1234
+        );
+        assertThrows(IllegalArgumentException.class, () -> metadata.setWrittenByMajor(Version.LATEST.major + 1));
+    }
+
+    public void testUploadedSegmentMetadataToStringExceptionTooOld() {
+        RemoteSegmentStoreDirectory.UploadedSegmentMetadata metadata = new RemoteSegmentStoreDirectory.UploadedSegmentMetadata(
+            "abc",
+            "pqr",
+            "123456",
+            1234
+        );
+        assertThrows(IllegalArgumentException.class, () -> metadata.setWrittenByMajor(Version.LATEST.major - 2));
+    }
+
+    public void testUploadedSegmentMetadataFromString() {
+        RemoteSegmentStoreDirectory.UploadedSegmentMetadata metadata = RemoteSegmentStoreDirectory.UploadedSegmentMetadata.fromString(
+            "_0.cfe::_0.cfe__uuidxyz::4567::372000::" + Version.LATEST.major
+        );
+        assertEquals("_0.cfe::_0.cfe__uuidxyz::4567::372000::" + Version.LATEST.major, metadata.toString());
+    }
+
+    public void testUploadedSegmentMetadataFromStringException() {
+        assertThrows(
+            ArrayIndexOutOfBoundsException.class,
+            () -> RemoteSegmentStoreDirectory.UploadedSegmentMetadata.fromString("_0.cfe::_0.cfe__uuidxyz::4567::372000")
+        );
+    }
+
+    public void testGetPrimaryTermGenerationUuid() {
+        String[] filenameTokens = "abc__9223372036854775795__9223372036854775784__uuid_xyz".split(
+            RemoteSegmentStoreDirectory.MetadataFilenameUtils.SEPARATOR
+        );
+        assertEquals(12, RemoteSegmentStoreDirectory.MetadataFilenameUtils.getPrimaryTerm(filenameTokens));
+        assertEquals(23, RemoteSegmentStoreDirectory.MetadataFilenameUtils.getGeneration(filenameTokens));
+    }
+
+    public void testInitException() throws IOException {
+        when(remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX, METADATA_FILES_TO_FETCH)).thenThrow(
+            new IOException("Error")
+        );
+
+        assertThrows(IOException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testInitNoMetadataFile() throws IOException {
+        when(remoteMetadataDirectory.listFilesByPrefix(RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX)).thenReturn(
+            List.of()
+        );
+
+        remoteSegmentStoreDirectory.init();
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> actualCache = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertEquals(Set.of(), actualCache.keySet());
+    }
+
+    public void testInitMultipleMetadataFile() throws IOException {
+        when(remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX, METADATA_FILES_TO_FETCH)).thenReturn(
+            List.of(metadataFilename, metadataFilenameDup)
+        );
+        assertThrows(IllegalStateException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    private Map<String, Map<String, String>> populateMetadata() throws IOException {
+        List<String> metadataFiles = new ArrayList<>();
+
+        metadataFiles.add(metadataFilename);
+        metadataFiles.add(metadataFilename2);
+        metadataFiles.add(metadataFilename3);
+
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(List.of(metadataFilename));
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                Integer.MAX_VALUE
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, Map<String, String>> metadataFilenameContentMapping = Map.of(
+            metadataFilename,
+            getDummyMetadata("_0", 1),
+            metadataFilename2,
+            getDummyMetadata("_0", 1),
+            metadataFilename3,
+            getDummyMetadata("_0", 1)
+        );
+
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenAnswer(
+            I -> createMetadataFileBytes(
+                metadataFilenameContentMapping.get(metadataFilename),
+                indexShard.getLatestReplicationCheckpoint(),
+                segmentInfos
+            )
+        );
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename2)).thenAnswer(
+            I -> createMetadataFileBytes(
+                metadataFilenameContentMapping.get(metadataFilename2),
+                indexShard.getLatestReplicationCheckpoint(),
+                segmentInfos
+            )
+        );
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename3)).thenAnswer(
+            I -> createMetadataFileBytes(
+                metadataFilenameContentMapping.get(metadataFilename3),
+                indexShard.getLatestReplicationCheckpoint(),
+                segmentInfos
+            )
+        );
+
+        return metadataFilenameContentMapping;
+    }
+
+    public void testInit() throws IOException {
+        populateMetadata();
+
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(List.of(metadataFilename));
+
+        remoteSegmentStoreDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> actualCache = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertEquals(Set.of("_0.cfe", "_0.cfs", "_0.si", "segments_1"), actualCache.keySet());
+    }
+
+    public void testListAll() throws IOException {
+        populateMetadata();
+
+        assertEquals(Set.of("_0.cfe", "_0.cfs", "_0.si", "segments_1"), Set.of(remoteSegmentStoreDirectory.listAll()));
+    }
+
+    public void testDeleteFile() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertTrue(uploadedSegments.containsKey("_0.si"));
+        assertFalse(uploadedSegments.containsKey("_100.si"));
+
+        remoteSegmentStoreDirectory.deleteFile("_0.si");
+        remoteSegmentStoreDirectory.deleteFile("_100.si");
+
+        verify(remoteDataDirectory).deleteFile(startsWith("_0.si"));
+        verify(remoteDataDirectory, times(0)).deleteFile(startsWith("_100.si"));
+        assertFalse(uploadedSegments.containsKey("_0.si"));
+    }
+
+    public void testDeleteFileException() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        doThrow(new IOException("Error")).when(remoteDataDirectory).deleteFile(any());
+        assertThrows(IOException.class, () -> remoteSegmentStoreDirectory.deleteFile("_0.si"));
+    }
+
+    public void testFileLength() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertTrue(uploadedSegments.containsKey("_0.si"));
+
+        assertEquals(uploadedSegments.get("_0.si").getLength(), remoteSegmentStoreDirectory.fileLength("_0.si"));
+    }
+
+    public void testFileLengthNoSuchFile() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertFalse(uploadedSegments.containsKey("_100.si"));
+        assertThrows(NoSuchFileException.class, () -> remoteSegmentStoreDirectory.fileLength("_100.si"));
+    }
+
+    public void testCreateOutput() throws IOException {
+        IndexOutput indexOutput = mock(IndexOutput.class);
+        when(remoteDataDirectory.createOutput(startsWith("abc"), eq(IOContext.DEFAULT))).thenReturn(indexOutput);
+
+        assertEquals(indexOutput, remoteSegmentStoreDirectory.createOutput("abc", IOContext.DEFAULT));
+    }
+
+    public void testCreateOutputException() {
+        when(remoteDataDirectory.createOutput(startsWith("abc"), eq(IOContext.DEFAULT))).thenThrow(new IOException("Error"));
+
+        assertThrows(IOException.class, () -> remoteSegmentStoreDirectory.createOutput("abc", IOContext.DEFAULT));
+    }
+
+    public void testOpenInput() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        IndexInput indexInput = mock(IndexInput.class);
+        when(remoteDataDirectory.openInput(startsWith("_0.si"), eq(IOContext.DEFAULT))).thenReturn(indexInput);
+
+        assertEquals(indexInput, remoteSegmentStoreDirectory.openInput("_0.si", IOContext.DEFAULT));
+    }
+
+    public void testOpenInputNoSuchFile() {
+        assertThrows(NoSuchFileException.class, () -> remoteSegmentStoreDirectory.openInput("_0.si", IOContext.DEFAULT));
+    }
+
+    public void testOpenInputException() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        when(remoteDataDirectory.openInput(startsWith("_0.si"), eq(IOContext.DEFAULT))).thenThrow(new IOException("Error"));
+
+        assertThrows(IOException.class, () -> remoteSegmentStoreDirectory.openInput("_0.si", IOContext.DEFAULT));
+    }
+
+    public void testAcquireLock() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+        String acquirerId = "test-acquirer";
+        long testPrimaryTerm = 1;
+        long testGeneration = 5;
+
+        List<String> metadataFiles = List.of("metadata__1__5__abc");
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilePrefixForCommit(testPrimaryTerm, testGeneration),
+                1
+            )
+        ).thenReturn(metadataFiles);
+
+        remoteSegmentStoreDirectory.acquireLock(testPrimaryTerm, testGeneration, acquirerId);
+        verify(mdLockManager).acquire(any());
+    }
+
+    public void testAcquireLockNoSuchFile() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+        String testAcquirerId = "test-acquirer";
+        long testPrimaryTerm = 2;
+        long testGeneration = 3;
+
+        assertThrows(
+            NoSuchFileException.class,
+            () -> remoteSegmentStoreDirectory.acquireLock(testPrimaryTerm, testGeneration, testAcquirerId)
+        );
+    }
+
+    public void testReleaseLock() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+        String testAcquirerId = "test-acquirer";
+        long testPrimaryTerm = 1;
+        long testGeneration = 5;
+
+        List<String> metadataFiles = List.of("metadata__1__5__abc");
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilePrefixForCommit(testPrimaryTerm, testGeneration),
+                1
+            )
+        ).thenReturn(metadataFiles);
+
+        remoteSegmentStoreDirectory.releaseLock(testPrimaryTerm, testGeneration, testAcquirerId);
+        verify(mdLockManager).release(any());
+    }
+
+    public void testIsAcquired() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+        long testPrimaryTerm = 1;
+        long testGeneration = 5;
+
+        List<String> metadataFiles = List.of("metadata__1__5__abc");
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilePrefixForCommit(testPrimaryTerm, testGeneration),
+                1
+            )
+        ).thenReturn(metadataFiles);
+
+        remoteSegmentStoreDirectory.isLockAcquired(testPrimaryTerm, testGeneration);
+        verify(mdLockManager).isAcquired(any());
+    }
+
+    public void testIsAcquiredException() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+        long testPrimaryTerm = 1;
+        long testGeneration = 5;
+
+        List<String> metadataFiles = new ArrayList<>();
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilePrefixForCommit(testPrimaryTerm, testGeneration),
+                1
+            )
+        ).thenReturn(metadataFiles);
+
+        assertThrows(NoSuchFileException.class, () -> remoteSegmentStoreDirectory.isLockAcquired(testPrimaryTerm, testGeneration));
+    }
+
+    public void testGetMetadataFileForCommit() throws IOException {
+        long testPrimaryTerm = 2;
+        long testGeneration = 3;
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilePrefixForCommit(testPrimaryTerm, testGeneration),
+                1
+            )
+        ).thenReturn(List.of("metadata__" + testPrimaryTerm + "__" + testGeneration + "__pqr"));
+
+        String output = remoteSegmentStoreDirectory.getMetadataFileForCommit(testPrimaryTerm, testGeneration);
+        assertEquals("metadata__" + testPrimaryTerm + "__" + testGeneration + "__pqr", output);
+
+    }
+
+    public void testCopyFrom() throws IOException {
+        String filename = "_100.si";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+        IndexOutput indexOutput = storeDirectory.createOutput(filename, IOContext.DEFAULT);
+        indexOutput.writeString("Hello World!");
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        storeDirectory.sync(List.of(filename));
+
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+        remoteSegmentStoreDirectory.copyFrom(storeDirectory, filename, filename, IOContext.DEFAULT);
+        assertTrue(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+
+        storeDirectory.close();
+    }
+
+    public void testCopyFilesFromMultipart() throws Exception {
+        String filename = "_100.si";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+        IndexOutput indexOutput = storeDirectory.createOutput(filename, IOContext.DEFAULT);
+        indexOutput.writeString("Hello World!");
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        storeDirectory.sync(List.of(filename));
+
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        when(remoteDataDirectory.getBlobContainer()).thenReturn(blobContainer);
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onResponse(null);
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+
+        CountDownLatch latch = new CountDownLatch(1);
+        ActionListener<Void> completionListener = new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void unused) {
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        remoteSegmentStoreDirectory.copyFrom(storeDirectory, filename, IOContext.DEFAULT, completionListener);
+        assertTrue(latch.await(5000, TimeUnit.SECONDS));
+        assertTrue(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+        storeDirectory.close();
+    }
+
+    public void testCopyFilesToMultipart() throws Exception {
+        String filename = "_0.cfe";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        when(remoteDataDirectory.getBlobContainer()).thenReturn(blobContainer);
+
+        Mockito.doAnswer(invocation -> {
+            ActionListener<ReadContext> completionListener = invocation.getArgument(1);
+            final CompletableFuture<InputStreamContainer> future = new CompletableFuture<>();
+            future.complete(new InputStreamContainer(new ByteArrayInputStream(new byte[] { 42 }), 0, 1));
+            completionListener.onResponse(new ReadContext(1, List.of(() -> future), ""));
+            return null;
+        }).when(blobContainer).readBlobAsync(any(), any());
+
+        CountDownLatch downloadLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(String unused) {
+                downloadLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        Path path = createTempDir();
+        remoteSegmentStoreDirectory.copyTo(filename, storeDirectory, path, completionListener);
+        assertTrue(downloadLatch.await(5000, TimeUnit.SECONDS));
+        verify(blobContainer, times(1)).readBlobAsync(contains(filename), any());
+        verify(storeDirectory, times(0)).copyFrom(any(), any(), any(), any());
+    }
+
+    public void testCopyFilesTo() throws Exception {
+        String filename = "_0.cfe";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        CountDownLatch downloadLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(String unused) {
+                downloadLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        Path path = createTempDir();
+        remoteSegmentStoreDirectory.copyTo(filename, storeDirectory, path, completionListener);
+        assertTrue(downloadLatch.await(5000, TimeUnit.MILLISECONDS));
+        verify(storeDirectory, times(1)).copyFrom(any(), eq(filename), eq(filename), eq(IOContext.DEFAULT));
+    }
+
+    public void testCopyFilesToEmptyPath() throws Exception {
+        String filename = "_0.cfe";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        when(remoteDataDirectory.getBlobContainer()).thenReturn(blobContainer);
+
+        CountDownLatch downloadLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(String unused) {
+                downloadLatch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {}
+        };
+        remoteSegmentStoreDirectory.copyTo(filename, storeDirectory, null, completionListener);
+        assertTrue(downloadLatch.await(5000, TimeUnit.MILLISECONDS));
+        verify(storeDirectory, times(1)).copyFrom(any(), eq(filename), eq(filename), eq(IOContext.DEFAULT));
+    }
+
+    public void testCopyFilesToException() throws Exception {
+        String filename = "_0.cfe";
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        Mockito.doThrow(new IOException())
+            .when(storeDirectory)
+            .copyFrom(any(Directory.class), anyString(), anyString(), any(IOContext.class));
+        CountDownLatch downloadLatch = new CountDownLatch(1);
+        ActionListener<String> completionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(String unused) {
+
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                downloadLatch.countDown();
+            }
+        };
+        Path path = createTempDir();
+        remoteSegmentStoreDirectory.copyTo(filename, storeDirectory, path, completionListener);
+        assertTrue(downloadLatch.await(5000, TimeUnit.MILLISECONDS));
+        verify(storeDirectory, times(1)).copyFrom(any(), eq(filename), eq(filename), eq(IOContext.DEFAULT));
+    }
+
+    public void testCopyFilesFromMultipartIOException() throws Exception {
+        String filename = "_100.si";
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        remoteDataDirectory = new RemoteDirectory(blobContainer);
+        remoteSegmentStoreDirectory = new RemoteSegmentStoreDirectory(
+            remoteDataDirectory,
+            remoteMetadataDirectory,
+            mdLockManager,
+            threadPool,
+            indexShard.shardId(),
+            DefaultRecoverySettings.INSTANCE
+        );
+
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+        IndexOutput indexOutput = storeDirectory.createOutput(filename, IOContext.DEFAULT);
+        indexOutput.writeString("Hello World!");
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        storeDirectory.sync(List.of(filename));
+
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onFailure(new Exception("Test exception"));
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        CountDownLatch latch = new CountDownLatch(1);
+        ActionListener<Void> completionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(Void unused) {}
+
+            @Override
+            public void onFailure(Exception e) {
+                latch.countDown();
+            }
+        };
+        remoteSegmentStoreDirectory.copyFrom(storeDirectory, filename, IOContext.DEFAULT, completionListener);
+        assertTrue(latch.await(5000, TimeUnit.SECONDS));
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+
+        storeDirectory.close();
+    }
+
+    public void testCopyFromException() throws IOException {
+        String filename = "_100.si";
+        Directory storeDirectory = LuceneTestCase.newDirectory();
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+        doThrow(new IOException("Error")).when(remoteDataDirectory).copyFrom(storeDirectory, filename, filename, IOContext.DEFAULT);
+
+        assertThrows(IOException.class, () -> remoteSegmentStoreDirectory.copyFrom(storeDirectory, filename, filename, IOContext.DEFAULT));
+        assertFalse(remoteSegmentStoreDirectory.getSegmentsUploadedToRemoteStore().containsKey(filename));
+
+        storeDirectory.close();
+    }
+
+    public void testContainsFile() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::512::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::1024::" + Version.LATEST.major);
+
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(
+            createMetadataFileBytes(metadata, indexShard.getLatestReplicationCheckpoint(), segmentInfos)
+        );
+
+        remoteSegmentStoreDirectory.init();
+
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegmentMetadataMap = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+
+        assertThrows(
+            UnsupportedOperationException.class,
+            () -> uploadedSegmentMetadataMap.put(
+                "_100.si",
+                new RemoteSegmentStoreDirectory.UploadedSegmentMetadata("_100.si", "_100.si__uuid1", "1234", 500)
+            )
+        );
+
+        assertTrue(remoteSegmentStoreDirectory.containsFile("_0.cfe", "1234"));
+        assertTrue(remoteSegmentStoreDirectory.containsFile("_0.cfs", "2345"));
+        assertFalse(remoteSegmentStoreDirectory.containsFile("_0.cfe", "1234000"));
+        assertFalse(remoteSegmentStoreDirectory.containsFile("_0.cfs", "2345000"));
+        assertFalse(remoteSegmentStoreDirectory.containsFile("_0.si", "23"));
+    }
+
+    public void testUploadMetadataEmpty() throws IOException {
+        Directory storeDirectory = mock(Directory.class);
+        IndexOutput indexOutput = mock(IndexOutput.class);
+        final long primaryTerm = indexShard.getOperationPrimaryTerm();
+        when(storeDirectory.createOutput(startsWith("metadata__" + primaryTerm + "__o"), eq(IOContext.DEFAULT))).thenReturn(indexOutput);
+
+        Collection<String> segmentFiles = List.of("_s1.si", "_s1.cfe", "_s3.cfs");
+        assertThrows(
+            NoSuchFileException.class,
+            () -> remoteSegmentStoreDirectory.uploadMetadata(
+                segmentFiles,
+                segmentInfos,
+                storeDirectory,
+                34L,
+                indexShard.getLatestReplicationCheckpoint(),
+                ""
+            )
+        );
+    }
+
+    public void testUploadMetadataNonEmpty() throws IOException {
+        indexDocs(142364, 5);
+        flushShard(indexShard, true);
+        SegmentInfos segInfos = indexShard.store().readLastCommittedSegmentsInfo();
+        long primaryTerm = indexShard.getLatestReplicationCheckpoint().getPrimaryTerm();
+        String primaryTermLong = RemoteStoreUtils.invertLong(primaryTerm);
+        long generation = segInfos.getGeneration();
+        String generationLong = RemoteStoreUtils.invertLong(generation);
+        String latestMetadataFileName = "metadata__" + primaryTermLong + "__" + generationLong + "__abc";
+        List<String> metadataFiles = List.of(latestMetadataFileName);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+        Map<String, Map<String, String>> metadataFilenameContentMapping = Map.of(
+            latestMetadataFileName,
+            getDummyMetadata("_0", (int) generation)
+        );
+        when(remoteMetadataDirectory.getBlobStream(latestMetadataFileName)).thenReturn(
+            createMetadataFileBytes(
+                metadataFilenameContentMapping.get(latestMetadataFileName),
+                indexShard.getLatestReplicationCheckpoint(),
+                segmentInfos
+            )
+        );
+
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        BytesStreamOutput output = new BytesStreamOutput();
+        IndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        when(storeDirectory.createOutput(startsWith("metadata__" + primaryTermLong + "__" + generationLong), eq(IOContext.DEFAULT)))
+            .thenReturn(indexOutput);
+
+        remoteSegmentStoreDirectory.uploadMetadata(
+            segInfos.files(true),
+            segInfos,
+            storeDirectory,
+            generation,
+            indexShard.getLatestReplicationCheckpoint(),
+            ""
+        );
+
+        verify(remoteMetadataDirectory).copyFrom(
+            eq(storeDirectory),
+            startsWith("metadata__" + primaryTermLong + "__" + generationLong),
+            startsWith("metadata__" + primaryTermLong + "__" + generationLong),
+            eq(IOContext.DEFAULT)
+        );
+        VersionedCodecStreamWrapper<RemoteSegmentMetadata> streamWrapper = new VersionedCodecStreamWrapper<>(
+            new RemoteSegmentMetadataHandler(),
+            RemoteSegmentMetadata.CURRENT_VERSION,
+            RemoteSegmentMetadata.METADATA_CODEC
+        );
+        RemoteSegmentMetadata remoteSegmentMetadata = streamWrapper.readStream(
+            new ByteArrayIndexInput("expected", BytesReference.toBytes(output.bytes()))
+        );
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> actual = remoteSegmentStoreDirectory
+            .getSegmentsUploadedToRemoteStore();
+        Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> expected = remoteSegmentMetadata.getMetadata();
+        for (String filename : expected.keySet()) {
+            assertEquals(expected.get(filename).toString(), actual.get(filename).toString());
+        }
+    }
+
+    public void testUploadMetadataMissingSegment() throws IOException {
+        populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        Directory storeDirectory = mock(Directory.class);
+        IndexOutput indexOutput = mock(IndexOutput.class);
+
+        String generation = RemoteStoreUtils.invertLong(segmentInfos.getGeneration());
+        long primaryTermLong = indexShard.getLatestReplicationCheckpoint().getPrimaryTerm();
+        String primaryTerm = RemoteStoreUtils.invertLong(primaryTermLong);
+        when(storeDirectory.createOutput(startsWith("metadata__" + primaryTerm + "__" + generation), eq(IOContext.DEFAULT))).thenReturn(
+            indexOutput
+        );
+
+        Collection<String> segmentFiles = List.of("_123.si");
+        assertThrows(
+            NoSuchFileException.class,
+            () -> remoteSegmentStoreDirectory.uploadMetadata(
+                segmentFiles,
+                segmentInfos,
+                storeDirectory,
+                12L,
+                indexShard.getLatestReplicationCheckpoint(),
+                ""
+            )
+        );
+        verify(indexOutput).close();
+        verify(storeDirectory).deleteFile(startsWith("metadata__" + primaryTerm + "__" + generation));
+    }
+
+    public void testUploadMetadataNoSegmentCommitInfos() throws IOException {
+        SegmentInfos segInfos = indexShard.store().readLastCommittedSegmentsInfo();
+        int numSegCommitInfos = segInfos.size();
+        assertEquals(
+            "For a fresh index, the number of SegmentCommitInfo instances associated with the SegmentInfos instance should be 0, but were found to be "
+                + numSegCommitInfos,
+            0,
+            numSegCommitInfos
+        );
+    }
+
+    public void testNoMetadataHeaderCorruptIndexException() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::" + Version.LATEST.major);
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        indexOutput.writeMapOfStrings(metadata);
+        indexOutput.close();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(inputStream);
+
+        assertThrows(CorruptIndexException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testInvalidCodecHeaderCorruptIndexException() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::" + Version.LATEST.major);
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        CodecUtil.writeHeader(indexOutput, "invalidCodec", RemoteSegmentMetadata.CURRENT_VERSION);
+        indexOutput.writeMapOfStrings(metadata);
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(inputStream);
+
+        assertThrows(CorruptIndexException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testHeaderMinVersionCorruptIndexException() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::" + Version.LATEST.major);
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        CodecUtil.writeHeader(indexOutput, RemoteSegmentMetadata.METADATA_CODEC, -1);
+        indexOutput.writeMapOfStrings(metadata);
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(inputStream);
+
+        assertThrows(IndexFormatTooOldException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testHeaderMaxVersionCorruptIndexException() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::" + Version.LATEST.major);
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        CodecUtil.writeHeader(indexOutput, RemoteSegmentMetadata.METADATA_CODEC, 2);
+        indexOutput.writeMapOfStrings(metadata);
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(inputStream);
+
+        assertThrows(IndexFormatTooNewException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testIncorrectChecksumCorruptIndexException() throws IOException {
+        List<String> metadataFiles = List.of(metadataFilename);
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                METADATA_FILES_TO_FETCH
+            )
+        ).thenReturn(metadataFiles);
+
+        Map<String, String> metadata = new HashMap<>();
+        metadata.put("_0.cfe", "_0.cfe::_0.cfe__" + UUIDs.base64UUID() + "::1234::512::" + Version.LATEST.major);
+        metadata.put("_0.cfs", "_0.cfs::_0.cfs__" + UUIDs.base64UUID() + "::2345::1024::" + Version.LATEST.major);
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        IndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        IndexOutput wrappedIndexOutput = new WrapperIndexOutput(indexOutput);
+        IndexOutput indexOutputSpy = spy(wrappedIndexOutput);
+        CodecUtil.writeHeader(indexOutputSpy, RemoteSegmentMetadata.METADATA_CODEC, RemoteSegmentMetadata.CURRENT_VERSION);
+        indexOutputSpy.writeMapOfStrings(metadata);
+        doReturn(12345L).when(indexOutputSpy).getChecksum();
+        CodecUtil.writeFooter(indexOutputSpy);
+        indexOutputSpy.close();
+
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+        when(remoteMetadataDirectory.getBlobStream(metadataFilename)).thenReturn(inputStream);
+
+        assertThrows(CorruptIndexException.class, () -> remoteSegmentStoreDirectory.init());
+    }
+
+    public void testDeleteStaleCommitsException() throws Exception {
+        populateMetadata();
+        when(
+            remoteMetadataDirectory.listFilesByPrefixInLexicographicOrder(
+                RemoteSegmentStoreDirectory.MetadataFilenameUtils.METADATA_PREFIX,
+                Integer.MAX_VALUE
+            )
+        ).thenThrow(new IOException("Error reading"));
+
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here to validate that in case of exception deleteFile is not
+        // invoked
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory, times(0)).deleteFile(any(String.class));
+    }
+
+    public void testDeleteStaleCommitsExceptionWhileScheduling() throws Exception {
+        populateMetadata();
+        doThrow(new IllegalArgumentException()).when(threadPool).executor(any(String.class));
+
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here to validate that in case of exception deleteFile is not
+        // invoked
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory, times(0)).deleteFile(any(String.class));
+    }
+
+    public void testDeleteStaleCommitsWithDeletionAlreadyInProgress() throws Exception {
+        populateMetadata();
+        remoteSegmentStoreDirectory.canDeleteStaleCommits.set(false);
+
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here to validate that in case of exception deleteFile is not
+        // invoked
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(false)));
+        verify(remoteMetadataDirectory, times(0)).deleteFile(any(String.class));
+    }
+
+    public void testDeleteStaleCommitsWithinThreshold() throws Exception {
+        populateMetadata();
+
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=5 here so that none of the metadata files will be deleted
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(5);
+
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory, times(0)).openInput(any(String.class), eq(IOContext.DEFAULT));
+    }
+
+    public void testDeleteStaleCommitsActualDelete() throws Exception {
+        Map<String, Map<String, String>> metadataFilenameContentMapping = populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here so that oldest 1 metadata file will be deleted
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        for (String metadata : metadataFilenameContentMapping.get(metadataFilename3).values()) {
+            String uploadedFilename = metadata.split(RemoteSegmentStoreDirectory.UploadedSegmentMetadata.SEPARATOR)[1];
+            verify(remoteDataDirectory).deleteFile(uploadedFilename);
+        }
+        ;
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory).deleteFile(metadataFilename3);
+    }
+
+    public void testDeleteStaleCommitsActualDeleteIOException() throws Exception {
+        Map<String, Map<String, String>> metadataFilenameContentMapping = populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        String segmentFileWithException = metadataFilenameContentMapping.get(metadataFilename3)
+            .values()
+            .stream()
+            .findAny()
+            .get()
+            .split(RemoteSegmentStoreDirectory.UploadedSegmentMetadata.SEPARATOR)[1];
+        doThrow(new IOException("Error")).when(remoteDataDirectory).deleteFile(segmentFileWithException);
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here so that oldest 1 metadata file will be deleted
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        for (String metadata : metadataFilenameContentMapping.get(metadataFilename3).values()) {
+            String uploadedFilename = metadata.split(RemoteSegmentStoreDirectory.UploadedSegmentMetadata.SEPARATOR)[1];
+            verify(remoteDataDirectory).deleteFile(uploadedFilename);
+        }
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory, times(0)).deleteFile(metadataFilename3);
+    }
+
+    public void testDeleteStaleCommitsActualDeleteNoSuchFileException() throws Exception {
+        Map<String, Map<String, String>> metadataFilenameContentMapping = populateMetadata();
+        remoteSegmentStoreDirectory.init();
+
+        String segmentFileWithException = metadataFilenameContentMapping.get(metadataFilename)
+            .values()
+            .stream()
+            .findAny()
+            .get()
+            .split(RemoteSegmentStoreDirectory.UploadedSegmentMetadata.SEPARATOR)[1];
+        doThrow(new NoSuchFileException(segmentFileWithException)).when(remoteDataDirectory).deleteFile(segmentFileWithException);
+        // popluateMetadata() adds stub to return 3 metadata files
+        // We are passing lastNMetadataFilesToKeep=2 here so that oldest 1 metadata file will be deleted
+        remoteSegmentStoreDirectory.deleteStaleSegmentsAsync(2);
+
+        for (String metadata : metadataFilenameContentMapping.get(metadataFilename3).values()) {
+            String uploadedFilename = metadata.split(RemoteSegmentStoreDirectory.UploadedSegmentMetadata.SEPARATOR)[1];
+            verify(remoteDataDirectory).deleteFile(uploadedFilename);
+        }
+        assertBusy(() -> assertThat(remoteSegmentStoreDirectory.canDeleteStaleCommits.get(), is(true)));
+        verify(remoteMetadataDirectory).deleteFile(metadataFilename3);
+    }
+
+    public void testSegmentMetadataCurrentVersion() {
+        /*
+          This is a fake test which will fail whenever the CURRENT_VERSION is incremented.
+          This is to bring attention of the author towards backward compatibility of metadata files.
+          If there is any breaking change the author needs to specify how old metadata file will be supported after
+          this change
+          If author doesn't want to support old metadata files. Then this can be ignored.
+          After taking appropriate action, fix this test by setting the correct version here
+         */
+        assertEquals(RemoteSegmentMetadata.CURRENT_VERSION, 1);
+    }
+
+    private void indexDocs(int startDocId, int numberOfDocs) throws IOException {
+        for (int i = startDocId; i < startDocId + numberOfDocs; i++) {
+            indexDoc(indexShard, "_doc", Integer.toString(i));
+        }
+    }
+
+    public void testMetadataFileNameOrder() {
+        String file1 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(15, 21, 23, 1, 1, "");
+        String file2 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(15, 38, 38, 1, 1, "");
+        String file3 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(18, 12, 26, 1, 1, "");
+        String file4 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(15, 38, 32, 10, 1, "");
+        String file5 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(15, 38, 32, 1, 1, "");
+        String file6 = RemoteSegmentStoreDirectory.MetadataFilenameUtils.getMetadataFilename(15, 38, 32, 5, 1, "");
+
+        List<String> actualList = new ArrayList<>(List.of(file1, file2, file3, file4, file5, file6));
+        actualList.sort(String::compareTo);
+
+        assertEquals(List.of(file3, file2, file4, file6, file5, file1), actualList);
+    }
+
+    private static class WrapperIndexOutput extends IndexOutput {
+        public IndexOutput indexOutput;
+
+        public WrapperIndexOutput(IndexOutput indexOutput) {
+            super(indexOutput.toString(), indexOutput.getName());
+            this.indexOutput = indexOutput;
+        }
+
+        @Override
+        public final void writeByte(byte b) throws IOException {
+            this.indexOutput.writeByte(b);
+        }
+
+        @Override
+        public final void writeBytes(byte[] b, int offset, int length) throws IOException {
+            this.indexOutput.writeBytes(b, offset, length);
+        }
+
+        @Override
+        public void writeShort(short i) throws IOException {
+            this.indexOutput.writeShort(i);
+        }
+
+        @Override
+        public void writeInt(int i) throws IOException {
+            this.indexOutput.writeInt(i);
+        }
+
+        @Override
+        public void writeLong(long i) throws IOException {
+            this.indexOutput.writeLong(i);
+        }
+
+        @Override
+        public void close() throws IOException {
+            this.indexOutput.close();
+        }
+
+        @Override
+        public final long getFilePointer() {
+            return this.indexOutput.getFilePointer();
+        }
+
+        @Override
+        public long getChecksum() throws IOException {
+            return this.indexOutput.getChecksum();
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/StoreTests.java b/server/src/test/java/org/opensearch/index/store/StoreTests.java
index fdec86e7912fd..d7d326b325cc6 100644
--- a/server/src/test/java/org/opensearch/index/store/StoreTests.java
+++ b/server/src/test/java/org/opensearch/index/store/StoreTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.index.store;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
@@ -40,6 +39,7 @@
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.IndexFormatTooNewException;
 import org.apache.lucene.index.IndexFormatTooOldException;
 import org.apache.lucene.index.IndexNotFoundException;
@@ -51,7 +51,6 @@
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.SnapshotDeletionPolicy;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.ChecksumIndexInput;
 import org.apache.lucene.store.Directory;
@@ -60,29 +59,39 @@
 import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.NIOFSDirectory;
-import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Version;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.ShardLock;
-import org.opensearch.index.Index;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLease;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
 import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.FeatureFlagSetter;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.ByteArrayInputStream;
@@ -93,6 +102,7 @@
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -102,6 +112,8 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Collections.unmodifiableMap;
+import static org.opensearch.index.seqno.SequenceNumbers.LOCAL_CHECKPOINT_KEY;
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectory.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION;
 import static org.opensearch.test.VersionUtils.randomVersion;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
@@ -121,6 +133,12 @@ public class StoreTests extends OpenSearchTestCase {
         "index",
         Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT).build()
     );
+
+    IndexSettings SEGMENT_REPLICATION_INDEX_SETTINGS = new IndexSettings(
+        INDEX_SETTINGS.getIndexMetadata(),
+        Settings.builder().put(INDEX_SETTINGS.getSettings()).put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build()
+    );
+
     private static final Version MIN_SUPPORTED_LUCENE_VERSION = org.opensearch.Version.CURRENT
         .minimumIndexCompatibilityVersion().luceneVersion;
 
@@ -364,14 +382,14 @@ public void testNewChecksums() throws IOException {
         Store.MetadataSnapshot metadata;
         // check before we committed
         try {
-            store.getMetadata(null);
+            store.getMetadata();
             fail("no index present - expected exception");
         } catch (IndexNotFoundException ex) {
             // expected
         }
         writer.commit();
         writer.close();
-        metadata = store.getMetadata(null);
+        metadata = store.getMetadata();
         assertThat(metadata.asMap().isEmpty(), is(false));
         for (StoreFileMetadata meta : metadata) {
             try (IndexInput input = store.directory().openInput(meta.name(), IOContext.DEFAULT)) {
@@ -552,7 +570,7 @@ public void testRecoveryDiff() throws IOException, InterruptedException {
             }
             writer.commit();
             writer.close();
-            first = store.getMetadata(null);
+            first = store.getMetadata();
             assertDeleteContent(store, store.directory());
             store.close();
         }
@@ -581,7 +599,7 @@ public void testRecoveryDiff() throws IOException, InterruptedException {
             }
             writer.commit();
             writer.close();
-            second = store.getMetadata(null);
+            second = store.getMetadata();
         }
         Store.RecoveryDiff diff = first.recoveryDiff(second);
         assertThat(first.size(), equalTo(second.size()));
@@ -610,7 +628,7 @@ public void testRecoveryDiff() throws IOException, InterruptedException {
         writer.deleteDocuments(new Term("id", Integer.toString(random().nextInt(numDocs))));
         writer.commit();
         writer.close();
-        Store.MetadataSnapshot metadata = store.getMetadata(null);
+        Store.MetadataSnapshot metadata = store.getMetadata();
         StoreFileMetadata delFile = null;
         for (StoreFileMetadata md : metadata) {
             if (md.name().endsWith(".liv")) {
@@ -645,7 +663,7 @@ public void testRecoveryDiff() throws IOException, InterruptedException {
         writer.addDocument(docs.get(0));
         writer.close();
 
-        Store.MetadataSnapshot newCommitMetadata = store.getMetadata(null);
+        Store.MetadataSnapshot newCommitMetadata = store.getMetadata();
         Store.RecoveryDiff newCommitDiff = newCommitMetadata.recoveryDiff(metadata);
         if (delFile != null) {
             assertThat(newCommitDiff.identical.size(), equalTo(newCommitMetadata.size() - 5)); // segments_N, del file, cfs, cfe, si for the
@@ -710,7 +728,7 @@ public void testCleanupFromSnapshot() throws IOException {
             writer.addDocument(doc);
         }
 
-        Store.MetadataSnapshot firstMeta = store.getMetadata(null);
+        Store.MetadataSnapshot firstMeta = store.getMetadata();
 
         if (random().nextBoolean()) {
             for (int i = 0; i < docs; i++) {
@@ -731,7 +749,7 @@ public void testCleanupFromSnapshot() throws IOException {
         writer.commit();
         writer.close();
 
-        Store.MetadataSnapshot secondMeta = store.getMetadata(null);
+        Store.MetadataSnapshot secondMeta = store.getMetadata();
 
         if (randomBoolean()) {
             store.cleanupAndVerify("test", firstMeta);
@@ -781,7 +799,7 @@ public void testOnCloseCallback() throws IOException {
             assertEquals(shardId, theLock.getShardId());
             assertEquals(lock, theLock);
             count.incrementAndGet();
-        });
+        }, null);
         assertEquals(count.get(), 0);
 
         final int iters = randomIntBetween(1, 10);
@@ -792,6 +810,26 @@ public void testOnCloseCallback() throws IOException {
         assertEquals(count.get(), 1);
     }
 
+    public void testStoreShardPath() {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            .put(Store.INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), TimeValue.timeValueMinutes(0))
+            .build();
+        final Path path = createTempDir().resolve(shardId.getIndex().getUUID()).resolve(String.valueOf(shardId.id()));
+        final ShardPath shardPath = new ShardPath(false, path, path, shardId);
+        final Store store = new Store(
+            shardId,
+            IndexSettingsModule.newIndexSettings("index", settings),
+            StoreTests.newDirectory(random()),
+            new DummyShardLock(shardId),
+            Store.OnClose.EMPTY,
+            shardPath
+        );
+        assertEquals(shardPath, store.shardPath());
+        store.close();
+    }
+
     public void testStoreStats() throws IOException {
         final ShardId shardId = new ShardId("index", "_na_", 1);
         Settings settings = Settings.builder()
@@ -1000,7 +1038,7 @@ public void testMarkCorruptedOnTruncatedSegmentsFile() throws IOException {
 
         try {
             if (randomBoolean()) {
-                store.getMetadata(null);
+                store.getMetadata();
             } else {
                 store.readLastCommittedSegmentsInfo();
             }
@@ -1138,4 +1176,206 @@ public void testGetPendingFiles() throws IOException {
             }
         }
     }
+
+    public void testGetMetadataWithSegmentInfos() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(shardId, INDEX_SETTINGS, new NIOFSDirectory(createTempDir()), new DummyShardLock(shardId));
+        store.createEmpty(Version.LATEST);
+        SegmentInfos segmentInfos = Lucene.readSegmentInfos(store.directory());
+        Store.MetadataSnapshot metadataSnapshot = store.getMetadata(segmentInfos);
+        // loose check for equality
+        assertEquals(segmentInfos.getSegmentsFileName(), metadataSnapshot.getSegmentsFile().name());
+        store.close();
+    }
+
+    public void testCreateEmptyStore() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(shardId, INDEX_SETTINGS, new NIOFSDirectory(createTempDir()), new DummyShardLock(shardId));
+        store.createEmpty(Version.LATEST);
+        SegmentInfos segmentInfos = Lucene.readSegmentInfos(store.directory());
+        assertFalse(segmentInfos.getUserData().containsKey(Translog.TRANSLOG_UUID_KEY));
+        testDefaultUserData(segmentInfos);
+        store.close();
+    }
+
+    public void testCreateEmptyStoreWithTranlogUUID() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(shardId, INDEX_SETTINGS, new NIOFSDirectory(createTempDir()), new DummyShardLock(shardId));
+        store.createEmpty(Version.LATEST, "dummy-translog-UUID");
+        SegmentInfos segmentInfos = Lucene.readSegmentInfos(store.directory());
+        assertEquals("dummy-translog-UUID", segmentInfos.getUserData().get(Translog.TRANSLOG_UUID_KEY));
+        testDefaultUserData(segmentInfos);
+        store.close();
+    }
+
+    public void testCreateEmptyWithNullTranlogUUID() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(shardId, INDEX_SETTINGS, new NIOFSDirectory(createTempDir()), new DummyShardLock(shardId));
+        store.createEmpty(Version.LATEST, null);
+        SegmentInfos segmentInfos = Lucene.readSegmentInfos(store.directory());
+        assertFalse(segmentInfos.getUserData().containsKey(Translog.TRANSLOG_UUID_KEY));
+        testDefaultUserData(segmentInfos);
+        store.close();
+    }
+
+    private void testDefaultUserData(SegmentInfos segmentInfos) {
+        assertEquals("-1", segmentInfos.getUserData().get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
+        assertEquals("-1", segmentInfos.getUserData().get(SequenceNumbers.MAX_SEQ_NO));
+        assertEquals("-1", segmentInfos.getUserData().get(Engine.MAX_UNSAFE_AUTO_ID_TIMESTAMP_COMMIT_ID));
+    }
+
+    public void testGetSegmentMetadataMap() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(
+            shardId,
+            SEGMENT_REPLICATION_INDEX_SETTINGS,
+            new NIOFSDirectory(createTempDir()),
+            new DummyShardLock(shardId)
+        );
+        store.createEmpty(Version.LATEST);
+        final Map<String, StoreFileMetadata> metadataSnapshot = store.getSegmentMetadataMap(store.readLastCommittedSegmentsInfo());
+        // no docs indexed only _N file exists.
+        assertTrue(metadataSnapshot.isEmpty());
+
+        // commit some docs to create a commit point.
+        commitRandomDocs(store);
+
+        final Map<String, StoreFileMetadata> snapshotAfterCommit = store.getSegmentMetadataMap(store.readLastCommittedSegmentsInfo());
+        assertFalse(snapshotAfterCommit.isEmpty());
+        assertFalse(snapshotAfterCommit.keySet().stream().anyMatch((name) -> name.startsWith(IndexFileNames.SEGMENTS)));
+        store.close();
+    }
+
+    public void testSegmentReplicationDiff() {
+        final String segmentName = "_0.si";
+        final StoreFileMetadata SEGMENT_FILE = new StoreFileMetadata(segmentName, 1L, "0", Version.LATEST);
+        // source has file target is missing.
+        Store.RecoveryDiff diff = Store.segmentReplicationDiff(Map.of(segmentName, SEGMENT_FILE), Collections.emptyMap());
+        assertEquals(List.of(SEGMENT_FILE), diff.missing);
+        assertTrue(diff.different.isEmpty());
+        assertTrue(diff.identical.isEmpty());
+
+        // target has file not on source.
+        diff = Store.segmentReplicationDiff(Collections.emptyMap(), Map.of(segmentName, SEGMENT_FILE));
+        assertTrue(diff.missing.isEmpty());
+        assertTrue(diff.different.isEmpty());
+        assertTrue(diff.identical.isEmpty());
+
+        // source and target have identical file.
+        diff = Store.segmentReplicationDiff(Map.of(segmentName, SEGMENT_FILE), Map.of(segmentName, SEGMENT_FILE));
+        assertTrue(diff.missing.isEmpty());
+        assertTrue(diff.different.isEmpty());
+        assertEquals(List.of(SEGMENT_FILE), diff.identical);
+
+        // source has diff copy of same file as target.
+        StoreFileMetadata SOURCE_DIFF_FILE = new StoreFileMetadata(segmentName, 1L, "abc", Version.LATEST);
+        diff = Store.segmentReplicationDiff(Map.of(segmentName, SOURCE_DIFF_FILE), Map.of(segmentName, SEGMENT_FILE));
+        assertTrue(diff.missing.isEmpty());
+        assertEquals(List.of(SOURCE_DIFF_FILE), diff.different);
+        assertTrue(diff.identical.isEmpty());
+
+        // ignore _N files if included in source map.
+        final String segmentsFile = IndexFileNames.SEGMENTS.concat("_2");
+        StoreFileMetadata SEGMENTS_FILE = new StoreFileMetadata(segmentsFile, 1L, "abc", Version.LATEST);
+        diff = Store.segmentReplicationDiff(Map.of(segmentsFile, SEGMENTS_FILE), Collections.emptyMap());
+        assertTrue(diff.missing.isEmpty());
+        assertTrue(diff.different.isEmpty());
+        assertTrue(diff.identical.isEmpty());
+    }
+
+    @SuppressForbidden(reason = "sets the SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY feature flag")
+    public void testReadSegmentsFromOldIndices() throws Exception {
+        int expectedIndexCreatedVersionMajor = SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY_MINIMUM_VERSION.luceneVersion.major;
+        final String pathToTestIndex = "/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip";
+        Path tmp = createTempDir();
+        TestUtil.unzip(getClass().getResourceAsStream(pathToTestIndex), tmp);
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = null;
+
+        try {
+            FeatureFlagSetter.set(FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY);
+            IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(
+                "index",
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+                    .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+                    .build()
+            );
+            store = new Store(shardId, indexSettings, StoreTests.newMockFSDirectory(tmp), new DummyShardLock(shardId));
+            assertEquals(expectedIndexCreatedVersionMajor, store.readLastCommittedSegmentsInfo().getIndexCreatedVersionMajor());
+        } finally {
+            if (store != null) {
+                store.close();
+            }
+        }
+    }
+
+    public void testReadSegmentsFromOldIndicesFailure() throws IOException {
+        final String pathToTestIndex = "/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip";
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Path tmp = createTempDir();
+        TestUtil.unzip(getClass().getResourceAsStream(pathToTestIndex), tmp);
+        IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(
+            "index",
+            Settings.builder()
+                .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+                .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey())
+                .build()
+        );
+        Store store = new Store(shardId, indexSettings, StoreTests.newMockFSDirectory(tmp), new DummyShardLock(shardId));
+        assertThrows(IndexFormatTooOldException.class, store::readLastCommittedSegmentsInfo);
+        store.close();
+    }
+
+    public void testCommitSegmentInfos() throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(
+            shardId,
+            SEGMENT_REPLICATION_INDEX_SETTINGS,
+            StoreTests.newDirectory(random()),
+            new DummyShardLock(shardId)
+        );
+        commitRandomDocs(store);
+        final SegmentInfos lastCommittedInfos = store.readLastCommittedSegmentsInfo();
+        final long expectedLocalCheckpoint = 1;
+        final long expectedMaxSeqNo = 2;
+        store.commitSegmentInfos(lastCommittedInfos, expectedMaxSeqNo, expectedLocalCheckpoint);
+
+        final SegmentInfos updatedInfos = store.readLastCommittedSegmentsInfo();
+        assertEquals(lastCommittedInfos.getVersion(), updatedInfos.getVersion());
+        final Map<String, String> userData = updatedInfos.getUserData();
+        assertEquals(expectedLocalCheckpoint, Long.parseLong(userData.get(LOCAL_CHECKPOINT_KEY)));
+        assertEquals(expectedMaxSeqNo, Long.parseLong(userData.get(SequenceNumbers.MAX_SEQ_NO)));
+        deleteContent(store.directory());
+        IOUtils.close(store);
+    }
+
+    private void commitRandomDocs(Store store) throws IOException {
+        IndexWriter writer = indexRandomDocs(store);
+        writer.commit();
+        writer.close();
+    }
+
+    private IndexWriter indexRandomDocs(Store store) throws IOException {
+        IndexWriterConfig indexWriterConfig = newIndexWriterConfig(random(), new MockAnalyzer(random())).setCodec(
+            TestUtil.getDefaultCodec()
+        );
+        indexWriterConfig.setCommitOnClose(false);
+        indexWriterConfig.setIndexDeletionPolicy(NoDeletionPolicy.INSTANCE);
+        IndexWriter writer = new IndexWriter(store.directory(), indexWriterConfig);
+        int docs = 1 + random().nextInt(100);
+        writer.commit();
+        Document doc = new Document();
+        doc.add(new TextField("id", "" + docs++, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
+        doc.add(
+            new TextField(
+                "body",
+                TestUtil.randomRealisticUnicodeString(random()),
+                random().nextBoolean() ? Field.Store.YES : Field.Store.NO
+            )
+        );
+        doc.add(new SortedDocValuesField("dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
+        writer.addDocument(doc);
+        return writer;
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/store/StoreUtils.java b/server/src/test/java/org/opensearch/index/store/StoreUtils.java
index 293d043c2d5f7..f8c80bdc44c9f 100644
--- a/server/src/test/java/org/opensearch/index/store/StoreUtils.java
+++ b/server/src/test/java/org/opensearch/index/store/StoreUtils.java
@@ -34,8 +34,8 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.shard.ShardId;
 
 import java.nio.file.Path;
 
diff --git a/server/src/test/java/org/opensearch/index/store/TestUploadListener.java b/server/src/test/java/org/opensearch/index/store/TestUploadListener.java
new file mode 100644
index 0000000000000..a2a61a93371e8
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/TestUploadListener.java
@@ -0,0 +1,43 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store;
+
+import org.opensearch.common.util.UploadListener;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class TestUploadListener implements UploadListener {
+
+    private final ConcurrentHashMap<String, UploadStatus> uploadStatusMap = new ConcurrentHashMap<>();
+
+    enum UploadStatus {
+        BEFORE_UPLOAD,
+        UPLOAD_SUCCESS,
+        UPLOAD_FAILURE
+    }
+
+    @Override
+    public void beforeUpload(String file) {
+        uploadStatusMap.put(file, UploadStatus.BEFORE_UPLOAD);
+    }
+
+    @Override
+    public void onSuccess(String file) {
+        uploadStatusMap.put(file, UploadStatus.UPLOAD_SUCCESS);
+    }
+
+    @Override
+    public void onFailure(String file) {
+        uploadStatusMap.put(file, UploadStatus.UPLOAD_FAILURE);
+    }
+
+    public UploadStatus getUploadStatus(String file) {
+        return uploadStatusMap.get(file);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/lockmanager/FileLockInfoTests.java b/server/src/test/java/org/opensearch/index/store/lockmanager/FileLockInfoTests.java
new file mode 100644
index 0000000000000..f3a2f1859923e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/lockmanager/FileLockInfoTests.java
@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.file.NoSuchFileException;
+
+public class FileLockInfoTests extends OpenSearchTestCase {
+    String testMetadata = "testMetadata";
+    String testAcquirerId = "testAcquirerId";
+
+    public void testGenerateLockName() {
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).withAcquirerId(testAcquirerId).build();
+        assertEquals(fileLockInfo.generateLockName(), FileLockInfo.LockFileUtils.generateLockName(testMetadata, testAcquirerId));
+    }
+
+    public void testGenerateLockNameFailureCase1() {
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).build();
+        assertThrows(IllegalArgumentException.class, fileLockInfo::generateLockName);
+    }
+
+    public void testGenerateLockNameFailureCase2() {
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+        assertThrows(IllegalArgumentException.class, fileLockInfo::generateLockName);
+    }
+
+    public void testGetLockPrefix() {
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).build();
+        assertEquals(fileLockInfo.getLockPrefix(), testMetadata + RemoteStoreLockManagerUtils.SEPARATOR);
+    }
+
+    public void testGetLockPrefixFailureCase() {
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+        assertThrows(IllegalArgumentException.class, fileLockInfo::getLockPrefix);
+    }
+
+    public void testGetLocksForAcquirer() throws NoSuchFileException {
+        String[] locks = new String[] {
+            FileLockInfo.LockFileUtils.generateLockName(testMetadata, testAcquirerId),
+            FileLockInfo.LockFileUtils.generateLockName(testMetadata, "acquirerId2") };
+        FileLockInfo fileLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+
+        assertEquals(fileLockInfo.getLockForAcquirer(locks), FileLockInfo.LockFileUtils.generateLockName(testMetadata, testAcquirerId));
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactoryTests.java b/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactoryTests.java
new file mode 100644
index 0000000000000..897785849cf7b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreLockManagerFactoryTests.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Supplier;
+
+import org.mockito.ArgumentCaptor;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteStoreLockManagerFactoryTests extends OpenSearchTestCase {
+
+    private Supplier<RepositoriesService> repositoriesServiceSupplier;
+    private RepositoriesService repositoriesService;
+    private RemoteStoreLockManagerFactory remoteStoreLockManagerFactory;
+
+    @Before
+    public void setup() throws IOException {
+        repositoriesServiceSupplier = mock(Supplier.class);
+        repositoriesService = mock(RepositoriesService.class);
+        when(repositoriesServiceSupplier.get()).thenReturn(repositoriesService);
+        remoteStoreLockManagerFactory = new RemoteStoreLockManagerFactory(repositoriesServiceSupplier);
+    }
+
+    public void testNewLockManager() throws IOException {
+
+        String testRepository = "testRepository";
+        String testIndexUUID = "testIndexUUID";
+        String testShardId = "testShardId";
+
+        BlobStoreRepository repository = mock(BlobStoreRepository.class);
+        BlobStore blobStore = mock(BlobStore.class);
+        BlobContainer blobContainer = mock(BlobContainer.class);
+        when(repository.blobStore()).thenReturn(blobStore);
+        when(repository.basePath()).thenReturn(new BlobPath().add("base_path"));
+        when(blobStore.blobContainer(any())).thenReturn(blobContainer);
+        when(blobContainer.listBlobs()).thenReturn(Collections.emptyMap());
+
+        when(repositoriesService.repository(testRepository)).thenReturn(repository);
+
+        RemoteStoreLockManager lockManager = remoteStoreLockManagerFactory.newLockManager(testRepository, testIndexUUID, testShardId);
+
+        assertTrue(lockManager != null);
+        ArgumentCaptor<BlobPath> blobPathCaptor = ArgumentCaptor.forClass(BlobPath.class);
+        verify(blobStore, times(1)).blobContainer(blobPathCaptor.capture());
+        List<BlobPath> blobPaths = blobPathCaptor.getAllValues();
+        assertEquals("base_path/" + testIndexUUID + "/" + testShardId + "/segments/lock_files/", blobPaths.get(0).buildAsString());
+
+        verify(repositoriesService).repository(testRepository);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManagerTests.java b/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManagerTests.java
new file mode 100644
index 0000000000000..b4eac2c4548d5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/lockmanager/RemoteStoreMetadataLockManagerTests.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.lockmanager;
+
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexOutput;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+
+import junit.framework.TestCase;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RemoteStoreMetadataLockManagerTests extends OpenSearchTestCase {
+    private RemoteBufferedOutputDirectory lockDirectory;
+    private RemoteStoreMetadataLockManager remoteStoreMetadataLockManager;
+    String testLockName = "testLock";
+    String testMetadata = "testMetadata";
+    String testAcquirerId = "testAcquirerId";
+
+    @Before
+    public void setup() throws IOException {
+        lockDirectory = mock(RemoteBufferedOutputDirectory.class);
+
+        remoteStoreMetadataLockManager = new RemoteStoreMetadataLockManager(lockDirectory);
+    }
+
+    private Collection<String> getListOfLocksMock() {
+        return Arrays.asList(
+            String.join(RemoteStoreLockManagerUtils.SEPARATOR, testMetadata, testAcquirerId)
+                + RemoteStoreLockManagerUtils.LOCK_FILE_EXTENSION,
+            String.join(RemoteStoreLockManagerUtils.SEPARATOR, testMetadata, "acquirerId2")
+                + RemoteStoreLockManagerUtils.LOCK_FILE_EXTENSION
+        );
+    }
+
+    public void testAcquire() throws IOException {
+        IndexOutput indexOutput = mock(IndexOutput.class);
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).withAcquirerId(testAcquirerId).build();
+        when(lockDirectory.createOutput(eq(testLockInfo.generateLockName()), eq(IOContext.DEFAULT))).thenReturn(indexOutput);
+        remoteStoreMetadataLockManager.acquire(testLockInfo);
+        verify(indexOutput).close();
+    }
+
+    public void testAcquireOnlyFileToLockPassed() { // only fileToLock was passed to acquire call.
+        IndexOutput indexOutput = mock(IndexOutput.class);
+        when(lockDirectory.createOutput(eq(testLockName), eq(IOContext.DEFAULT))).thenReturn(indexOutput);
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).build();
+        assertThrows(IllegalArgumentException.class, () -> remoteStoreMetadataLockManager.acquire(testLockInfo));
+    }
+
+    public void testAcquireOnlyAcquirerIdPassed() { // only AcquirerId was passed to acquire call.
+        IndexOutput indexOutput = mock(IndexOutput.class);
+        when(lockDirectory.createOutput(eq(testLockName), eq(IOContext.DEFAULT))).thenReturn(indexOutput);
+        LockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+        assertThrows(IllegalArgumentException.class, () -> remoteStoreMetadataLockManager.acquire(testLockInfo));
+    }
+
+    public void testRelease() throws IOException {
+        when(lockDirectory.listAll()).thenReturn(getListOfLocksMock().toArray(new String[0]));
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+
+        remoteStoreMetadataLockManager.release(testLockInfo);
+        verify(lockDirectory).deleteFile(
+            String.join(RemoteStoreLockManagerUtils.SEPARATOR, testMetadata, testAcquirerId)
+                + RemoteStoreLockManagerUtils.LOCK_FILE_EXTENSION
+        );
+    }
+
+    public void testReleaseExceptionCase() { // acquirerId is Not passed during release lock call.
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).build();
+        assertThrows(IllegalArgumentException.class, () -> remoteStoreMetadataLockManager.release(testLockInfo));
+    }
+
+    public void testIsAcquired() throws IOException {
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withFileToLock(testMetadata).build();
+        when(lockDirectory.listFilesByPrefix(testLockInfo.getLockPrefix())).thenReturn(getListOfLocksMock());
+        TestCase.assertTrue(remoteStoreMetadataLockManager.isAcquired(testLockInfo));
+    }
+
+    public void testIsAcquiredExceptionCase() { // metadata file is not passed during isAcquired call.
+        FileLockInfo testLockInfo = FileLockInfo.getLockInfoBuilder().withAcquirerId(testAcquirerId).build();
+        assertThrows(IllegalArgumentException.class, () -> remoteStoreMetadataLockManager.isAcquired(testLockInfo));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/file/CleanerDaemonThreadLeakFilter.java b/server/src/test/java/org/opensearch/index/store/remote/file/CleanerDaemonThreadLeakFilter.java
new file mode 100644
index 0000000000000..8f7568a68f0d0
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/file/CleanerDaemonThreadLeakFilter.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.file;
+
+import com.carrotsearch.randomizedtesting.ThreadFilter;
+
+/**
+ * The {@link java.lang.ref.Cleaner} instance used by {@link OnDemandBlockSnapshotIndexInput} creates
+ * a daemon thread which is never stopped, nor do we have a handle to stop it. This filter
+ * excludes that thread from the leak detection logic.
+ */
+public final class CleanerDaemonThreadLeakFilter implements ThreadFilter {
+    @Override
+    public boolean reject(Thread t) {
+        return t.getName().startsWith(OnDemandBlockSnapshotIndexInput.CLEANER_THREAD_NAME_PREFIX);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInputLifecycleTests.java b/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInputLifecycleTests.java
new file mode 100644
index 0000000000000..b6e8c9c1b536a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockIndexInputLifecycleTests.java
@@ -0,0 +1,173 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.file;
+
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+import static org.hamcrest.Matchers.hasSize;
+
+/**
+ * Unit test to ensure that {@link OnDemandBlockIndexInput} properly closes
+ * all of its backing IndexInput instances, as the reference counting logic
+ * relies on this behavior.
+ */
+@ThreadLeakFilters(filters = CleanerDaemonThreadLeakFilter.class)
+public class OnDemandBlockIndexInputLifecycleTests extends OpenSearchTestCase {
+    private static final int ONE_MB_SHIFT = 20;
+    private static final int ONE_MB = 1 << ONE_MB_SHIFT;
+    private static final int TWO_MB = ONE_MB * 2;
+
+    private final List<CloseTrackingIndexInput> allIndexInputs = new ArrayList<>();
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+
+        assertBusy(() -> {
+            System.gc(); // Do not rely on GC to be deterministic, hence the polling
+            assertTrue("Expected all IndexInputs to be closed", allIndexInputs.stream().allMatch(CloseTrackingIndexInput::isClosed));
+        }, 5, TimeUnit.SECONDS);
+    }
+
+    public void testClose() throws IOException {
+        try (OnDemandBlockIndexInput indexInput = createTestOnDemandBlockIndexInput()) {
+            indexInput.seek(0);
+        }
+    }
+
+    public void testCloseWhenSeekingMultipleChunks() throws IOException {
+        try (OnDemandBlockIndexInput indexInput = createTestOnDemandBlockIndexInput()) {
+            indexInput.seek(0);
+            indexInput.seek(ONE_MB + 1);
+        }
+        MatcherAssert.assertThat("Expected to seek past first block and create a second block", allIndexInputs, hasSize(2));
+    }
+
+    public void testUnclosedCloneIsClosed() throws IOException {
+        try (OnDemandBlockIndexInput indexInput = createTestOnDemandBlockIndexInput()) {
+            indexInput.seek(0);
+
+            // Clone is abandoned without closing
+            indexInput.clone().seek(0);
+        }
+    }
+
+    public void testUnclosedSliceIsClosed() throws IOException {
+        try (OnDemandBlockIndexInput indexInput = createTestOnDemandBlockIndexInput()) {
+            indexInput.seek(0);
+
+            // Clone is abandoned without closing
+            indexInput.slice("slice", 0, 100).seek(0);
+        }
+    }
+
+    private OnDemandBlockIndexInput createTestOnDemandBlockIndexInput() {
+        return new TestOnDemandBlockIndexInput(this::createCloseTrackingIndexInput, false);
+    }
+
+    private IndexInput createCloseTrackingIndexInput() {
+        final CloseTrackingIndexInput i = new CloseTrackingIndexInput();
+        allIndexInputs.add(i);
+        return i;
+    }
+
+    /**
+     * Concrete implementation of {@link OnDemandBlockIndexInput} that creates
+     * {@link CloseTrackingIndexInput} index inputs when it needs to fetch a
+     * new block.
+     */
+    private static class TestOnDemandBlockIndexInput extends OnDemandBlockIndexInput {
+        private final Supplier<IndexInput> indexInputSupplier;
+
+        TestOnDemandBlockIndexInput(Supplier<IndexInput> indexInputSupplier, boolean isClone) {
+            super(
+                builder().blockSizeShift(ONE_MB_SHIFT)
+                    .offset(0)
+                    .length(TWO_MB)
+                    .isClone(isClone)
+                    .resourceDescription(TestOnDemandBlockIndexInput.class.getName())
+            );
+            this.indexInputSupplier = indexInputSupplier;
+        }
+
+        @Override
+        protected OnDemandBlockIndexInput buildSlice(String sliceDescription, long offset, long length) {
+            return new TestOnDemandBlockIndexInput(this.indexInputSupplier, true);
+        }
+
+        @Override
+        protected IndexInput fetchBlock(int blockId) throws IOException {
+            return indexInputSupplier.get();
+        }
+
+        @Override
+        public OnDemandBlockIndexInput clone() {
+            return new TestOnDemandBlockIndexInput(this.indexInputSupplier, true);
+        }
+    }
+
+    /**
+     * Simple implementation of an IndexInput that just tracks whether it has
+     * been closed. All other methods do nothing useful.
+     */
+    private static class CloseTrackingIndexInput extends IndexInput {
+
+        private boolean isClosed = false;
+
+        protected CloseTrackingIndexInput() {
+            super("TestIndexInput");
+        }
+
+        public boolean isClosed() {
+            return isClosed;
+        }
+
+        @Override
+        public void close() {
+            isClosed = true;
+        }
+
+        @Override
+        public long getFilePointer() {
+            return 0;
+        }
+
+        @Override
+        public void seek(long pos) {}
+
+        @Override
+        public long length() {
+            return 0;
+        }
+
+        @Override
+        public IndexInput slice(String sliceDescription, long offset, long length) {
+            return null;
+        }
+
+        @Override
+        public byte readByte() throws IOException {
+            return 0;
+        }
+
+        @Override
+        public void readBytes(byte[] b, int offset, int len) {}
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInputTests.java b/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInputTests.java
new file mode 100644
index 0000000000000..a04feea3bb8e5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/file/OnDemandBlockSnapshotIndexInputTests.java
@@ -0,0 +1,446 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.file;
+
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
+import org.apache.lucene.store.FSDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.LockFactory;
+import org.apache.lucene.store.MMapDirectory;
+import org.apache.lucene.store.SimpleFSLockFactory;
+import org.apache.lucene.util.Constants;
+import org.apache.lucene.util.Version;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.remote.utils.BlobFetchRequest;
+import org.opensearch.index.store.remote.utils.TransferManager;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.nio.file.Path;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+
+@ThreadLeakFilters(filters = CleanerDaemonThreadLeakFilter.class)
+public class OnDemandBlockSnapshotIndexInputTests extends OpenSearchTestCase {
+    // params shared by all test cases
+    private static final String RESOURCE_DESCRIPTION = "Test OnDemandBlockSnapshotIndexInput Block Size";
+    private static final long BLOCK_SNAPSHOT_FILE_OFFSET = 0;
+    private static final String FILE_NAME = "File_Name";
+    private static final String BLOCK_FILE_PREFIX = FILE_NAME;
+    private static final boolean IS_CLONE = false;
+    private static final ByteSizeValue BYTE_SIZE_VALUE = new ByteSizeValue(1L);
+    private static final int FILE_SIZE = 29360128;
+    private TransferManager transferManager;
+    private LockFactory lockFactory;
+    private BlobStoreIndexShardSnapshot.FileInfo fileInfo;
+    private Path path;
+
+    @Before
+    public void init() {
+        assumeFalse("Awaiting Windows fix https://github.com/opensearch-project/OpenSearch/issues/5396", Constants.WINDOWS);
+        transferManager = mock(TransferManager.class);
+        lockFactory = SimpleFSLockFactory.INSTANCE;
+        path = createTempDir("OnDemandBlockSnapshotIndexInputTests");
+    }
+
+    public void test8MBBlock() throws Exception {
+        runAllTestsFor(23);
+    }
+
+    public void test4KBBlock() throws Exception {
+        runAllTestsFor(12);
+    }
+
+    public void test1MBBlock() throws Exception {
+        runAllTestsFor(20);
+    }
+
+    public void test4MBBlock() throws Exception {
+        runAllTestsFor(22);
+    }
+
+    public void runAllTestsFor(int blockSizeShift) throws Exception {
+        final OnDemandBlockSnapshotIndexInput blockedSnapshotFile = createOnDemandBlockSnapshotIndexInput(blockSizeShift);
+        final int blockSize = 1 << blockSizeShift;
+        TestGroup.testGetBlock(blockedSnapshotFile, blockSize, FILE_SIZE);
+        TestGroup.testGetBlockOffset(blockedSnapshotFile, blockSize, FILE_SIZE);
+        TestGroup.testGetBlockStart(blockedSnapshotFile, blockSize);
+        TestGroup.testCurrentBlockStart(blockedSnapshotFile, blockSize);
+        TestGroup.testCurrentBlockPosition(blockedSnapshotFile, blockSize);
+        TestGroup.testClone(blockedSnapshotFile, blockSize);
+        TestGroup.testSlice(blockedSnapshotFile, blockSize);
+        TestGroup.testGetFilePointer(blockedSnapshotFile, blockSize);
+        TestGroup.testReadByte(blockedSnapshotFile, blockSize);
+        TestGroup.testReadShort(blockedSnapshotFile, blockSize);
+        TestGroup.testReadInt(blockedSnapshotFile, blockSize);
+        TestGroup.testReadLong(blockedSnapshotFile, blockSize);
+        TestGroup.testReadVInt(blockedSnapshotFile, blockSize);
+        TestGroup.testSeek(blockedSnapshotFile, blockSize, FILE_SIZE);
+        TestGroup.testReadByteWithPos(blockedSnapshotFile, blockSize);
+        TestGroup.testReadShortWithPos(blockedSnapshotFile, blockSize);
+        TestGroup.testReadIntWithPos(blockedSnapshotFile, blockSize);
+        TestGroup.testReadLongWithPos(blockedSnapshotFile, blockSize);
+        TestGroup.testReadBytes(blockedSnapshotFile, blockSize);
+    }
+
+    // create OnDemandBlockSnapshotIndexInput for each block size
+    private OnDemandBlockSnapshotIndexInput createOnDemandBlockSnapshotIndexInput(int blockSizeShift) throws IOException,
+        InterruptedException {
+
+        // file info should be initialized per test method since file size need to be calculated
+        fileInfo = new BlobStoreIndexShardSnapshot.FileInfo(
+            FILE_NAME,
+            new StoreFileMetadata(FILE_NAME, FILE_SIZE, "", Version.LATEST),
+            BYTE_SIZE_VALUE
+        );
+
+        int blockSize = 1 << blockSizeShift;
+
+        doAnswer(invocation -> {
+            BlobFetchRequest blobFetchRequest = invocation.getArgument(0);
+            return blobFetchRequest.getDirectory().openInput(blobFetchRequest.getFileName(), IOContext.READ);
+        }).when(transferManager).fetchBlob(any());
+
+        FSDirectory directory = null;
+        try {
+            // use MMapDirectory to create block
+            directory = new MMapDirectory(path, lockFactory);
+        } catch (IOException e) {
+            fail("fail to create MMapDirectory: " + e.getMessage());
+        }
+
+        initBlockFiles(blockSize, directory);
+
+        return new OnDemandBlockSnapshotIndexInput(
+            OnDemandBlockIndexInput.builder()
+                .resourceDescription(RESOURCE_DESCRIPTION)
+                .offset(BLOCK_SNAPSHOT_FILE_OFFSET)
+                .length(FILE_SIZE)
+                .blockSizeShift(blockSizeShift)
+                .isClone(IS_CLONE),
+            fileInfo,
+            directory,
+            transferManager
+        );
+    }
+
+    private void initBlockFiles(int blockSize, FSDirectory fsDirectory) {
+        int numOfBlocks = FILE_SIZE / blockSize;
+
+        int sizeOfLastBlock = FILE_SIZE % blockSize;
+
+        try {
+
+            // block size will always be an integer multiple of frame size
+            // write 48, -80 alternatively
+            for (int i = 0; i < numOfBlocks; i++) {
+                // create normal blocks
+                String blockName = BLOCK_FILE_PREFIX + "." + i;
+                IndexOutput output = fsDirectory.createOutput(blockName, null);
+                // since block size is always even number, safe to do division
+                for (int j = 0; j < blockSize / 2; j++) {
+                    // byte 00110000
+                    output.writeByte((byte) 48);
+                    // byte 10110000
+                    output.writeByte((byte) -80);
+                }
+                output.close();
+            }
+
+            if (numOfBlocks > 1 && sizeOfLastBlock != 0) {
+                // create last block
+                String lastBlockName = BLOCK_FILE_PREFIX + "." + numOfBlocks;
+                IndexOutput output = fsDirectory.createOutput(lastBlockName, null);
+                for (int i = 0; i < sizeOfLastBlock; i++) {
+                    if ((i & 1) == 0) {
+                        output.writeByte((byte) 48);
+                    } else {
+                        output.writeByte((byte) -80);
+                    }
+                }
+                output.close();
+            }
+
+        } catch (IOException e) {
+            fail("fail to initialize block files: " + e.getMessage());
+        }
+
+    }
+
+    public static class TestGroup {
+
+        public static void testGetBlock(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize, int fileSize) {
+            // block 0
+            assertEquals(0, blockedSnapshotFile.getBlock(0L));
+
+            // block 1
+            assertEquals(1, blockedSnapshotFile.getBlock(blockSize));
+
+            // end block
+            assertEquals((fileSize - 1) / blockSize, blockedSnapshotFile.getBlock(fileSize - 1));
+        }
+
+        public static void testGetBlockOffset(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize, int fileSize) {
+            // block 0
+            assertEquals(1, blockedSnapshotFile.getBlockOffset(1));
+
+            // block 1
+            assertEquals(0, blockedSnapshotFile.getBlockOffset(blockSize));
+
+            // end block
+            assertEquals((fileSize - 1) % blockSize, blockedSnapshotFile.getBlockOffset(fileSize - 1));
+        }
+
+        public static void testGetBlockStart(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) {
+            // block 0
+            assertEquals(0L, blockedSnapshotFile.getBlockStart(0));
+
+            // block 1
+            assertEquals(blockSize, blockedSnapshotFile.getBlockStart(1));
+
+            // block 2
+            assertEquals(blockSize * 2, blockedSnapshotFile.getBlockStart(2));
+        }
+
+        public static void testCurrentBlockStart(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            // block 0
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals(0L, blockedSnapshotFile.currentBlockStart());
+
+            // block 1
+            blockedSnapshotFile.seek(blockSize * 2 - 1);
+            assertEquals(blockSize, blockedSnapshotFile.currentBlockStart());
+
+            // block 2
+            blockedSnapshotFile.seek(blockSize * 3 - 1);
+            assertEquals(blockSize * 2, blockedSnapshotFile.currentBlockStart());
+        }
+
+        public static void testCurrentBlockPosition(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            // block 0
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals(blockSize - 1, blockedSnapshotFile.currentBlockPosition());
+
+            // block 1
+            blockedSnapshotFile.seek(blockSize + 1);
+            assertEquals(1, blockedSnapshotFile.currentBlockPosition());
+
+            // block 2
+            blockedSnapshotFile.seek(blockSize * 2 + 11);
+            assertEquals(11, blockedSnapshotFile.currentBlockPosition());
+        }
+
+        public static void testClone(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(blockSize + 1);
+            OnDemandBlockSnapshotIndexInput clonedFile = blockedSnapshotFile.clone();
+            assertEquals(clonedFile.currentBlockPosition(), blockedSnapshotFile.currentBlockPosition());
+            assertEquals(clonedFile.getFilePointer(), blockedSnapshotFile.getFilePointer());
+            clonedFile.seek(blockSize + 11);
+            assertNotEquals(clonedFile.currentBlockPosition(), blockedSnapshotFile.currentBlockPosition());
+        }
+
+        public static void testSlice(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            IndexInput slice = blockedSnapshotFile.slice("slice", blockSize - 11, 22);
+            OnDemandBlockSnapshotIndexInput newSlice = (OnDemandBlockSnapshotIndexInput) slice;
+
+            assertEquals(newSlice.isClone, true);
+            assertEquals(newSlice.transferManager, blockedSnapshotFile.transferManager);
+            assertEquals(newSlice.fileName, blockedSnapshotFile.fileName);
+            assertEquals(newSlice.blockMask, blockedSnapshotFile.blockMask);
+            assertEquals(newSlice.blockSize, blockedSnapshotFile.blockSize);
+            assertEquals(newSlice.blockSizeShift, blockedSnapshotFile.blockSizeShift);
+            assertEquals(newSlice.directory, blockedSnapshotFile.directory);
+            assertNotEquals(newSlice.length, blockedSnapshotFile.length);
+            assertNotEquals(newSlice.offset, blockedSnapshotFile.offset);
+
+            newSlice.seek(0);
+            assertEquals(0, newSlice.getFilePointer());
+            assertEquals(blockSize - 11, newSlice.currentBlockPosition());
+            newSlice.seek(21);
+            assertEquals(21, newSlice.getFilePointer());
+            assertEquals(10, newSlice.currentBlockPosition());
+
+            try {
+                newSlice.seek(23);
+            } catch (EOFException e) {
+                return;
+            }
+            fail("Able to seek past file end");
+        }
+
+        public static void testGetFilePointer(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(blockSize - 11);
+            assertEquals(blockSize - 11, blockedSnapshotFile.currentBlockPosition());
+            blockedSnapshotFile.seek(blockSize + 5);
+            assertEquals(5, blockedSnapshotFile.currentBlockPosition());
+            blockedSnapshotFile.seek(blockSize * 2);
+            assertEquals(0, blockedSnapshotFile.currentBlockPosition());
+        }
+
+        public static void testReadByte(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals((byte) 48, blockedSnapshotFile.readByte());
+            blockedSnapshotFile.seek(1);
+            assertEquals((byte) -80, blockedSnapshotFile.readByte());
+
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals((byte) -80, blockedSnapshotFile.readByte());
+            blockedSnapshotFile.seek(blockSize);
+            assertEquals((byte) 48, blockedSnapshotFile.readByte());
+        }
+
+        public static void testReadShort(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(-20432, blockedSnapshotFile.readShort());
+
+            blockedSnapshotFile.seek(blockSize);
+            assertEquals(-20432, blockedSnapshotFile.readShort());
+
+            // cross block 0 and block 1
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals(12464, blockedSnapshotFile.readShort());
+        }
+
+        public static void testReadInt(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(-1338986448, blockedSnapshotFile.readInt());
+
+            blockedSnapshotFile.seek(blockSize);
+            assertEquals(-1338986448, blockedSnapshotFile.readInt());
+
+            // 3 byte in block 0, 1 byte in block 1
+            blockedSnapshotFile.seek(blockSize - 3);
+            assertEquals(816853168, blockedSnapshotFile.readInt());
+            // 2 byte in block 0, 2 byte in block 1
+            blockedSnapshotFile.seek(blockSize - 2);
+            assertEquals(-1338986448, blockedSnapshotFile.readInt());
+            // 1 byte in block 0, 3 byte in block 1
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals(816853168, blockedSnapshotFile.readInt());
+        }
+
+        public static void testReadLong(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong());
+
+            // 7 byte in block 0, 1 byte in block 1
+            blockedSnapshotFile.seek(blockSize - 7);
+            assertEquals(3508357643010846896L, blockedSnapshotFile.readLong());
+
+            // 6 byte in block 0, 2 byte in block 2
+            blockedSnapshotFile.seek(blockSize - 6);
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong());
+
+            // 5 byte in block 0, 3 byte in block 3
+            blockedSnapshotFile.seek(blockSize - 5);
+            assertEquals(3508357643010846896L, blockedSnapshotFile.readLong());
+
+            // 4 byte in block 0, 4 block in block 4
+            blockedSnapshotFile.seek(blockSize - 4);
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong());
+        }
+
+        public static void testReadVInt(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(48, blockedSnapshotFile.readVInt());
+
+            blockedSnapshotFile.seek(blockSize - 1);
+            assertEquals(6192, blockedSnapshotFile.readVInt());
+        }
+
+        public static void testReadVLong(OnDemandBlockSnapshotIndexInput blockedSnapshotFile) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(48, blockedSnapshotFile.readVLong());
+
+            blockedSnapshotFile.seek(1);
+            assertEquals(6192, blockedSnapshotFile.readVLong());
+        }
+
+        public static void testSeek(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize, int fileSize) throws IOException {
+            blockedSnapshotFile.seek(0);
+            assertEquals(0, blockedSnapshotFile.currentBlockPosition());
+
+            blockedSnapshotFile.seek(blockSize + 11);
+            assertEquals(11, blockedSnapshotFile.currentBlockPosition());
+
+            try {
+                blockedSnapshotFile.seek(fileSize + 1);
+            } catch (EOFException e) {
+                return;
+            }
+            fail("Able to seek past end");
+        }
+
+        public static void testReadByteWithPos(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            assertEquals(48, blockedSnapshotFile.readByte(0));
+            assertEquals(-80, blockedSnapshotFile.readByte(1));
+
+            assertEquals(48, blockedSnapshotFile.readByte(blockSize));
+            assertEquals(-80, blockedSnapshotFile.readByte(blockSize + 1));
+        }
+
+        public static void testReadShortWithPos(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            assertEquals(-20432, blockedSnapshotFile.readShort(0));
+            assertEquals(12464, blockedSnapshotFile.readShort(1));
+
+            assertEquals(12464, blockedSnapshotFile.readShort(blockSize - 1));
+            assertEquals(-20432, blockedSnapshotFile.readShort(blockSize));
+        }
+
+        public static void testReadIntWithPos(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            assertEquals(-1338986448, blockedSnapshotFile.readInt(0));
+            assertEquals(-1338986448, blockedSnapshotFile.readInt(blockSize));
+
+            // 3 byte in block 0, 1 byte in block 1
+            assertEquals(816853168, blockedSnapshotFile.readInt(blockSize - 3));
+            // 2 byte in block 0, 2 byte in block 1
+            assertEquals(-1338986448, blockedSnapshotFile.readInt(blockSize - 2));
+            // 1 byte in block 0, 3 byte in block 1
+            assertEquals(816853168, blockedSnapshotFile.readInt(blockSize - 1));
+        }
+
+        public static void testReadLongWithPos(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong(0));
+
+            // 7 byte in block 0, 1 byte in block 1
+            assertEquals(3508357643010846896L, blockedSnapshotFile.readLong(blockSize - 7));
+
+            // 6 byte in block 0, 2 byte in block 2
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong(blockSize - 6));
+
+            // 5 byte in block 0, 3 byte in block 3
+            assertEquals(3508357643010846896L, blockedSnapshotFile.readLong(blockSize - 5));
+
+            // 4 byte in block 0, 4 block in block 4
+            assertEquals(-5750903000991223760L, blockedSnapshotFile.readLong(blockSize - 4));
+        }
+
+        public static void testReadBytes(OnDemandBlockSnapshotIndexInput blockedSnapshotFile, int blockSize) throws IOException {
+            byte[] byteArr = new byte[2];
+            blockedSnapshotFile.seek(0);
+            blockedSnapshotFile.readBytes(byteArr, 0, 2);
+            assertEquals(48, byteArr[0]);
+            assertEquals(-80, byteArr[1]);
+
+            blockedSnapshotFile.seek(blockSize - 1);
+            blockedSnapshotFile.readBytes(byteArr, 0, 2);
+            assertEquals(-80, byteArr[0]);
+            assertEquals(48, byteArr[1]);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheCleanerTests.java b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheCleanerTests.java
new file mode 100644
index 0000000000000..04434fa52e555
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheCleanerTests.java
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.ShardPath;
+import org.opensearch.indices.cluster.IndicesClusterStateService;
+import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory.LOCAL_STORE_LOCATION;
+import static org.hamcrest.Matchers.equalTo;
+
+public class FileCacheCleanerTests extends OpenSearchTestCase {
+    private static final ShardId SHARD_0 = new ShardId("index", "uuid-0", 0);
+    private static final ShardId SHARD_1 = new ShardId("index", "uuid-1", 0);
+    private static final Settings SETTINGS = Settings.builder()
+        .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+        .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+        .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+        .put("index.store.type", "remote_snapshot")
+        .build();
+    private static final IndexSettings INDEX_SETTINGS = new IndexSettings(
+        IndexMetadata.builder("index").settings(SETTINGS).build(),
+        SETTINGS
+    );
+
+    private final FileCache fileCache = FileCacheFactory.createConcurrentLRUFileCache(
+        1024 * 1024,
+        1,
+        new NoopCircuitBreaker(CircuitBreaker.REQUEST)
+    );
+    private final Map<ShardId, Path> files = new HashMap<>();
+    private NodeEnvironment env;
+    private FileCacheCleaner cleaner;
+
+    @Before
+    public void setUpFileCache() throws IOException {
+        env = newNodeEnvironment(SETTINGS);
+        cleaner = new FileCacheCleaner(env, fileCache);
+        files.put(SHARD_0, addFile(fileCache, env, SHARD_0));
+        files.put(SHARD_1, addFile(fileCache, env, SHARD_1));
+        MatcherAssert.assertThat(fileCache.size(), equalTo(2L));
+    }
+
+    private static Path addFile(FileCache fileCache, NodeEnvironment env, ShardId shardId) throws IOException {
+        final ShardPath shardPath = ShardPath.loadFileCachePath(env, shardId);
+        final Path localStorePath = shardPath.getDataPath().resolve(LOCAL_STORE_LOCATION);
+        Files.createDirectories(localStorePath);
+        final Path file = Files.createFile(localStorePath.resolve("file"));
+        fileCache.put(file, new CachedIndexInput() {
+            @Override
+            public IndexInput getIndexInput() {
+                return null;
+            }
+
+            @Override
+            public long length() {
+                return 1024;
+            }
+
+            @Override
+            public boolean isClosed() {
+                return false;
+            }
+
+            @Override
+            public void close() {
+
+            }
+        });
+        return file;
+    }
+
+    @After
+    public void tearDownFileCache() {
+        env.close();
+    }
+
+    public void testShardRemoved() {
+        final Path cachePath = ShardPath.loadFileCachePath(env, SHARD_0).getDataPath();
+        assertTrue(Files.exists(cachePath));
+
+        cleaner.beforeIndexShardDeleted(SHARD_0, SETTINGS);
+        MatcherAssert.assertThat(fileCache.size(), equalTo(1L));
+        assertNull(fileCache.get(files.get(SHARD_0)));
+        assertFalse(Files.exists(files.get(SHARD_0)));
+        assertTrue(Files.exists(files.get(SHARD_1)));
+        cleaner.afterIndexShardDeleted(SHARD_0, SETTINGS);
+        assertFalse(Files.exists(cachePath));
+    }
+
+    public void testIndexRemoved() {
+        final Path indexCachePath = env.fileCacheNodePath().fileCachePath.resolve(SHARD_0.getIndex().getUUID());
+        assertTrue(Files.exists(indexCachePath));
+
+        cleaner.beforeIndexShardDeleted(SHARD_0, SETTINGS);
+        cleaner.afterIndexShardDeleted(SHARD_0, SETTINGS);
+        cleaner.beforeIndexShardDeleted(SHARD_1, SETTINGS);
+        cleaner.afterIndexShardDeleted(SHARD_1, SETTINGS);
+        cleaner.afterIndexRemoved(
+            SHARD_0.getIndex(),
+            INDEX_SETTINGS,
+            IndicesClusterStateService.AllocatedIndices.IndexRemovalReason.DELETED
+        );
+        MatcherAssert.assertThat(fileCache.size(), equalTo(0L));
+        assertFalse(Files.exists(indexCachePath));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheStatsTests.java b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheStatsTests.java
new file mode 100644
index 0000000000000..7931c6fec5414
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheStatsTests.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.index.store.remote.utils.cache.CacheUsage;
+import org.opensearch.index.store.remote.utils.cache.stats.CacheStats;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class FileCacheStatsTests extends OpenSearchTestCase {
+    private static final long BYTES_IN_GB = 1024 * 1024 * 1024;
+
+    public static CacheStats getMockCacheStats() {
+        final long evicted = randomLongBetween(10000, BYTES_IN_GB);
+        final long removed = randomLongBetween(10000, BYTES_IN_GB);
+        final long replaced = randomLongBetween(0, 10000);
+        final long hits = randomLongBetween(0, 10000);
+        final long miss = randomLongBetween(0, 10000);
+        return new CacheStats(hits, miss, 0, removed, replaced, 0, evicted);
+    }
+
+    public static CacheUsage getMockCacheUsage(long total) {
+        final long used = randomLongBetween(100, total);
+        final long active = randomLongBetween(10, used);
+        return new CacheUsage(used, active);
+    }
+
+    public static long getMockCacheCapacity() {
+        return randomLongBetween(10 * BYTES_IN_GB, 1000 * BYTES_IN_GB);
+    }
+
+    public static FileCacheStats getFileCacheStats(final long fileCacheCapacity, final CacheStats stats, final CacheUsage usage) {
+        return new FileCacheStats(
+            System.currentTimeMillis(),
+            usage.activeUsage(),
+            fileCacheCapacity,
+            usage.usage(),
+            stats.evictionWeight(),
+            stats.hitCount(),
+            stats.missCount()
+        );
+    }
+
+    public static FileCacheStats getMockFileCacheStats() {
+        final long fcSize = getMockCacheCapacity();
+        return getFileCacheStats(fcSize, getMockCacheStats(), getMockCacheUsage(fcSize));
+    }
+
+    public static void validateFileCacheStats(FileCacheStats original, FileCacheStats deserialized) {
+        assertEquals(original.getTotal(), deserialized.getTotal());
+        assertEquals(original.getUsed(), deserialized.getUsed());
+        assertEquals(original.getUsedPercent(), deserialized.getUsedPercent());
+        assertEquals(original.getActive(), deserialized.getActive());
+        assertEquals(original.getActivePercent(), deserialized.getActivePercent());
+        assertEquals(original.getEvicted(), deserialized.getEvicted());
+        assertEquals(original.getCacheHits(), deserialized.getCacheHits());
+        assertEquals(original.getCacheMisses(), deserialized.getCacheMisses());
+    }
+
+    public void testFileCacheStatsSerialization() throws IOException {
+        final FileCacheStats fileCacheStats = getMockFileCacheStats();
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            fileCacheStats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                // Validate original object against deserialized values
+                validateFileCacheStats(fileCacheStats, new FileCacheStats(in));
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheTests.java b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheTests.java
new file mode 100644
index 0000000000000..c1e3636cc9928
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/filecache/FileCacheTests.java
@@ -0,0 +1,322 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.filecache;
+
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.breaker.TestCircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.env.NodeEnvironment;
+import org.opensearch.index.store.remote.directory.RemoteSnapshotDirectoryFactory;
+import org.opensearch.index.store.remote.utils.cache.CacheUsage;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+public class FileCacheTests extends OpenSearchTestCase {
+    // need concurrency level to be static to make these tests more deterministic because capacity per segment is dependent on
+    // (total capacity) / (concurrency level) so having high concurrency level might trigger early evictions which is tolerable in real life
+    // but fatal to these tests
+    private final static int CONCURRENCY_LEVEL = 16;
+    private final static int MEGA_BYTES = 1024 * 1024;
+    private final static String FAKE_PATH_SUFFIX = "Suffix";
+    private Path path;
+
+    @Before
+    public void init() throws Exception {
+        path = createTempDir("FileCacheTests");
+    }
+
+    private FileCache createFileCache(long capacity) {
+        return FileCacheFactory.createConcurrentLRUFileCache(capacity, CONCURRENCY_LEVEL, new NoopCircuitBreaker(CircuitBreaker.REQUEST));
+    }
+
+    private FileCache createCircuitBreakingFileCache(long capacity) {
+        TestCircuitBreaker testCircuitBreaker = new TestCircuitBreaker();
+        testCircuitBreaker.startBreaking();
+        return FileCacheFactory.createConcurrentLRUFileCache(capacity, CONCURRENCY_LEVEL, testCircuitBreaker);
+    }
+
+    private Path createPath(String middle) {
+        return path.resolve(middle).resolve(FAKE_PATH_SUFFIX);
+    }
+
+    @SuppressForbidden(reason = "creating a test file for cache")
+    private void createFile(String indexName, String shardId, String fileName) throws IOException {
+        Path folderPath = path.resolve(NodeEnvironment.CACHE_FOLDER)
+            .resolve(indexName)
+            .resolve(shardId)
+            .resolve(RemoteSnapshotDirectoryFactory.LOCAL_STORE_LOCATION);
+        Path filePath = folderPath.resolve(fileName);
+        Files.createDirectories(folderPath);
+        Files.createFile(filePath);
+        Files.write(filePath, "test-data".getBytes());
+    }
+
+    // test get method
+    public void testGet() {
+        FileCache fileCache = createFileCache(8 * MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            fileCache.put(createPath(Integer.toString(i)), new StubCachedIndexInput(8 * MEGA_BYTES));
+        }
+        // verify all blocks are put into file cache
+        for (int i = 0; i < 4; i++) {
+            assertNotNull(fileCache.get(createPath(Integer.toString(i))));
+        }
+    }
+
+    public void testGetThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.get(null);
+        });
+    }
+
+    public void testPutThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.put(null, null);
+        });
+    }
+
+    public void testPutThrowCircuitBreakingException() {
+        FileCache fileCache = createCircuitBreakingFileCache(MEGA_BYTES);
+        Path path = createPath("0");
+        assertThrows(CircuitBreakingException.class, () -> fileCache.put(path, new StubCachedIndexInput(8 * MEGA_BYTES)));
+        assertNull(fileCache.get(path));
+    }
+
+    public void testCompute() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        Path path = createPath("0");
+        fileCache.put(path, new StubCachedIndexInput(8 * MEGA_BYTES));
+        fileCache.incRef(path);
+        fileCache.compute(path, (p, i) -> null);
+        // item will be removed
+        assertEquals(fileCache.size(), 0);
+    }
+
+    public void testComputeThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.compute(null, null);
+        });
+    }
+
+    public void testComputeThrowCircuitBreakingException() {
+        FileCache fileCache = createCircuitBreakingFileCache(MEGA_BYTES);
+        Path path = createPath("0");
+        assertThrows(CircuitBreakingException.class, () -> fileCache.compute(path, (p, i) -> new StubCachedIndexInput(8 * MEGA_BYTES)));
+        assertNull(fileCache.get(path));
+    }
+
+    public void testRemove() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            fileCache.put(createPath(Integer.toString(i)), new StubCachedIndexInput(8 * MEGA_BYTES));
+        }
+
+        fileCache.remove(createPath("0"));
+        fileCache.remove(createPath("0"));
+        fileCache.remove(createPath("1"));
+        assertEquals(fileCache.size(), 2);
+        assertNotNull(fileCache.get(createPath("2")));
+        assertNotNull(fileCache.get(createPath("3")));
+    }
+
+    public void testRemoveThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.remove(null);
+        });
+    }
+
+    public void testIncDecRef() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            fileCache.put(createPath(Integer.toString(i)), new StubCachedIndexInput(8 * MEGA_BYTES));
+        }
+
+        // try to evict previous IndexInput
+        for (int i = 1000; i < 3000; i++) {
+            putAndDecRef(fileCache, i, 8 * MEGA_BYTES);
+        }
+
+        // IndexInput with refcount greater than 0 will not be evicted
+        for (int i = 0; i < 4; i++) {
+            assertNotNull(fileCache.get(createPath(Integer.toString(i))));
+            fileCache.decRef(createPath(Integer.toString(i)));
+        }
+
+        // decrease ref
+        for (int i = 0; i < 4; i++) {
+            fileCache.decRef(createPath(Integer.toString(i)));
+        }
+
+        // try to evict previous IndexInput again
+        for (int i = 3000; i < 5000; i++) {
+            putAndDecRef(fileCache, i, 8 * MEGA_BYTES);
+        }
+
+        for (int i = 0; i < 4; i++) {
+            assertNull(fileCache.get(createPath(Integer.toString(i))));
+        }
+    }
+
+    public void testIncRefThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.incRef(null);
+        });
+
+    }
+
+    public void testDecRefThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            FileCache fileCache = createFileCache(MEGA_BYTES);
+            fileCache.decRef(null);
+        });
+
+    }
+
+    public void testCapacity() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        assertEquals(fileCache.capacity(), MEGA_BYTES);
+    }
+
+    public void testSize() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            fileCache.put(createPath(Integer.toString(i)), new StubCachedIndexInput(8 * MEGA_BYTES));
+        }
+        // test file cache size
+        assertEquals(fileCache.size(), 4);
+    }
+
+    public void testPrune() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            putAndDecRef(fileCache, i, 8 * MEGA_BYTES);
+        }
+        // before prune
+        assertTrue(fileCache.size() >= 1);
+
+        fileCache.prune();
+        // after prune
+        assertEquals(0, fileCache.size());
+    }
+
+    public void testPruneWithPredicate() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            putAndDecRef(fileCache, i, 8 * MEGA_BYTES);
+        }
+
+        // before prune
+        assertTrue(fileCache.size() >= 1);
+
+        // after prune with false predicate
+        fileCache.prune(path -> false);
+        assertTrue(fileCache.size() >= 1);
+
+        // after prune with true predicate
+        fileCache.prune(path -> true);
+        assertEquals(0, fileCache.size());
+    }
+
+    public void testUsage() {
+        FileCache fileCache = FileCacheFactory.createConcurrentLRUFileCache(
+            16 * MEGA_BYTES,
+            1,
+            new NoopCircuitBreaker(CircuitBreaker.REQUEST)
+        );
+        putAndDecRef(fileCache, 0, 16 * MEGA_BYTES);
+
+        CacheUsage expectedCacheUsage = new CacheUsage(16 * MEGA_BYTES, 0);
+        CacheUsage realCacheUsage = fileCache.usage();
+        assertEquals(expectedCacheUsage.activeUsage(), realCacheUsage.activeUsage());
+        assertEquals(expectedCacheUsage.usage(), realCacheUsage.usage());
+    }
+
+    public void testStats() {
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        for (int i = 0; i < 4; i++) {
+            fileCache.put(createPath(Integer.toString(i)), new StubCachedIndexInput(8 * MEGA_BYTES));
+        }
+        // cache hits
+        fileCache.get(createPath("0"));
+        fileCache.get(createPath("1"));
+        // cache misses
+        fileCache.get(createPath("-1"));
+        fileCache.get(createPath("-2"));
+
+        assertEquals(fileCache.stats().hitCount(), 2);
+
+        // do some eviction here
+        for (int i = 0; i < 2000; i++) {
+            putAndDecRef(fileCache, i, 8 * MEGA_BYTES);
+        }
+        assertTrue(fileCache.stats().evictionCount() > 0);
+        assertTrue(fileCache.stats().evictionWeight() > 0);
+
+    }
+
+    public void testCacheRestore() throws IOException {
+        String indexName = "test-index";
+        String shardId = "0";
+        createFile(indexName, shardId, "test.0");
+        FileCache fileCache = createFileCache(MEGA_BYTES);
+        assertEquals(0, fileCache.usage().usage());
+        Path fileCachePath = path.resolve(NodeEnvironment.CACHE_FOLDER).resolve(indexName).resolve(shardId);
+        fileCache.restoreFromDirectory(List.of(fileCachePath));
+        assertTrue(fileCache.usage().usage() > 0);
+        assertEquals(0, fileCache.usage().activeUsage());
+    }
+
+    private void putAndDecRef(FileCache cache, int path, long indexInputSize) {
+        final Path key = createPath(Integer.toString(path));
+        cache.put(key, new StubCachedIndexInput(indexInputSize));
+        cache.decRef(key);
+    }
+
+    public static class StubCachedIndexInput implements CachedIndexInput {
+
+        private final long length;
+
+        public StubCachedIndexInput(long length) {
+            this.length = length;
+        }
+
+        @Override
+        public IndexInput getIndexInput() {
+            return null;
+        }
+
+        @Override
+        public long length() {
+            return length;
+        }
+
+        @Override
+        public boolean isClosed() {
+            return false;
+        }
+
+        @Override
+        public void close() throws Exception {
+
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandlerTests.java b/server/src/test/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandlerTests.java
new file mode 100644
index 0000000000000..f5d54dc790e76
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandlerTests.java
@@ -0,0 +1,163 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.metadata;
+
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.ByteBuffersDataOutput;
+import org.apache.lucene.store.ByteBuffersIndexOutput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.apache.lucene.util.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.Store;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Unit Tests for {@link RemoteSegmentMetadataHandler}
+ */
+public class RemoteSegmentMetadataHandlerTests extends IndexShardTestCase {
+    private RemoteSegmentMetadataHandler remoteSegmentMetadataHandler;
+    private IndexShard indexShard;
+    private SegmentInfos segmentInfos;
+
+    private ReplicationCheckpoint replicationCheckpoint;
+
+    @Before
+    public void setup() throws IOException {
+        remoteSegmentMetadataHandler = new RemoteSegmentMetadataHandler();
+
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .build();
+
+        indexShard = newStartedShard(false, indexSettings, new NRTReplicationEngineFactory());
+        try (Store store = indexShard.store()) {
+            segmentInfos = store.readLastCommittedSegmentsInfo();
+        }
+        replicationCheckpoint = indexShard.getLatestReplicationCheckpoint();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        indexShard.close("test tearDown", true, false);
+        super.tearDown();
+    }
+
+    public void testReadContentNoSegmentInfos() throws IOException {
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        Map<String, String> expectedOutput = getDummyData();
+        indexOutput.writeMapOfStrings(expectedOutput);
+        RemoteSegmentMetadata.writeCheckpointToIndexOutput(replicationCheckpoint, indexOutput);
+        indexOutput.writeLong(0);
+        indexOutput.writeBytes(new byte[0], 0);
+        indexOutput.close();
+        RemoteSegmentMetadata metadata = remoteSegmentMetadataHandler.readContent(
+            new ByteArrayIndexInput("dummy bytes", BytesReference.toBytes(output.bytes()))
+        );
+        assertEquals(expectedOutput, metadata.toMapOfStrings());
+        assertEquals(replicationCheckpoint.getSegmentsGen(), metadata.getGeneration());
+    }
+
+    public void testReadContentWithSegmentInfos() throws IOException {
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        Map<String, String> expectedOutput = getDummyData();
+        indexOutput.writeMapOfStrings(expectedOutput);
+        RemoteSegmentMetadata.writeCheckpointToIndexOutput(replicationCheckpoint, indexOutput);
+        ByteBuffersIndexOutput segmentInfosOutput = new ByteBuffersIndexOutput(new ByteBuffersDataOutput(), "test", "resource");
+        segmentInfos.write(segmentInfosOutput);
+        byte[] segmentInfosBytes = segmentInfosOutput.toArrayCopy();
+        indexOutput.writeLong(segmentInfosBytes.length);
+        indexOutput.writeBytes(segmentInfosBytes, 0, segmentInfosBytes.length);
+        indexOutput.close();
+        RemoteSegmentMetadata metadata = remoteSegmentMetadataHandler.readContent(
+            new ByteArrayIndexInput("dummy bytes", BytesReference.toBytes(output.bytes()))
+        );
+        assertEquals(expectedOutput, metadata.toMapOfStrings());
+        assertEquals(replicationCheckpoint.getSegmentsGen(), metadata.getGeneration());
+        assertArrayEquals(segmentInfosBytes, metadata.getSegmentInfosBytes());
+    }
+
+    public void testWriteContent() throws IOException {
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+
+        Map<String, String> expectedOutput = getDummyData();
+        ByteBuffersIndexOutput segmentInfosOutput = new ByteBuffersIndexOutput(new ByteBuffersDataOutput(), "test", "resource");
+        segmentInfos.write(segmentInfosOutput);
+        byte[] segmentInfosBytes = segmentInfosOutput.toArrayCopy();
+
+        RemoteSegmentMetadata remoteSegmentMetadata = new RemoteSegmentMetadata(
+            RemoteSegmentMetadata.fromMapOfStrings(expectedOutput),
+            segmentInfosBytes,
+            indexShard.getLatestReplicationCheckpoint()
+        );
+        remoteSegmentMetadataHandler.writeContent(indexOutput, remoteSegmentMetadata);
+        indexOutput.close();
+
+        RemoteSegmentMetadata metadata = remoteSegmentMetadataHandler.readContent(
+            new ByteArrayIndexInput("dummy bytes", BytesReference.toBytes(output.bytes()))
+        );
+        assertEquals(expectedOutput, metadata.toMapOfStrings());
+        assertEquals(replicationCheckpoint.getSegmentsGen(), metadata.getGeneration());
+        assertEquals(replicationCheckpoint.getPrimaryTerm(), metadata.getPrimaryTerm());
+        assertArrayEquals(segmentInfosBytes, metadata.getSegmentInfosBytes());
+    }
+
+    private Map<String, String> getDummyData() {
+        Map<String, String> expectedOutput = new HashMap<>();
+        String prefix = "_0";
+        expectedOutput.put(
+            prefix + ".cfe",
+            prefix
+                + ".cfe::"
+                + prefix
+                + ".cfe__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(1024, 2048)
+                + "::"
+                + Version.LATEST.major
+        );
+        expectedOutput.put(
+            prefix + ".cfs",
+            prefix
+                + ".cfs::"
+                + prefix
+                + ".cfs__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(1024, 2048)
+                + "::"
+                + Version.LATEST.major
+        );
+        return expectedOutput;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/utils/TransferManagerTests.java b/server/src/test/java/org/opensearch/index/store/remote/utils/TransferManagerTests.java
new file mode 100644
index 0000000000000..d42e614302658
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/utils/TransferManagerTests.java
@@ -0,0 +1,228 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils;
+
+import com.carrotsearch.randomizedtesting.annotations.ThreadLeakFilters;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.MMapDirectory;
+import org.apache.lucene.store.SimpleFSLockFactory;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.index.store.remote.file.CleanerDaemonThreadLeakFilter;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheFactory;
+import org.opensearch.test.OpenSearchTestCase;
+import org.hamcrest.MatcherAssert;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+
+@ThreadLeakFilters(filters = CleanerDaemonThreadLeakFilter.class)
+public class TransferManagerTests extends OpenSearchTestCase {
+    private static final int EIGHT_MB = 1024 * 1024 * 8;
+    private final FileCache fileCache = FileCacheFactory.createConcurrentLRUFileCache(
+        EIGHT_MB * 2,
+        1,
+        new NoopCircuitBreaker(CircuitBreaker.REQUEST)
+    );
+    private MMapDirectory directory;
+    private BlobContainer blobContainer;
+    private TransferManager transferManager;
+
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        directory = new MMapDirectory(createTempDir(), SimpleFSLockFactory.INSTANCE);
+        blobContainer = mock(BlobContainer.class);
+        doAnswer(i -> new ByteArrayInputStream(createData())).when(blobContainer).readBlob(eq("blob"), anyLong(), anyLong());
+        transferManager = new TransferManager(blobContainer, fileCache);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+    }
+
+    private static byte[] createData() {
+        final byte[] data = new byte[EIGHT_MB];
+        data[EIGHT_MB - 1] = 7;
+        return data;
+    }
+
+    public void testSingleAccess() throws Exception {
+        try (IndexInput i = fetchBlobWithName("file")) {
+            assertIndexInputIsFunctional(i);
+            MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo((long) EIGHT_MB));
+        }
+        MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo(0L));
+        MatcherAssert.assertThat(fileCache.usage().usage(), equalTo((long) EIGHT_MB));
+    }
+
+    public void testConcurrentAccess() throws Exception {
+        // Kick off multiple threads that all concurrently request the same resource
+        final String blobname = "file";
+        final ExecutorService testRunner = Executors.newFixedThreadPool(8);
+        try {
+            final List<Future<IndexInput>> futures = new ArrayList<>();
+            for (int i = 0; i < 8; i++) {
+                futures.add(testRunner.submit(() -> fetchBlobWithName(blobname)));
+            }
+            // Wait for all threads to complete
+            for (Future<IndexInput> future : futures) {
+                future.get(1, TimeUnit.SECONDS);
+            }
+            // Assert that all IndexInputs are independently positioned by seeking
+            // to the end and closing each one. If not independent, then this would
+            // result in EOFExceptions and/or NPEs.
+            for (Future<IndexInput> future : futures) {
+                try (IndexInput i = future.get()) {
+                    assertIndexInputIsFunctional(i);
+                }
+            }
+        } finally {
+            assertTrue(terminate(testRunner));
+        }
+    }
+
+    public void testFetchBlobWithConcurrentCacheEvictions() throws Exception {
+        // Submit 256 tasks to an executor with 16 threads that will each randomly
+        // request one of eight blobs. Given that the cache can only hold two
+        // blobs this will lead to a huge amount of contention and thrashing.
+        final ExecutorService testRunner = Executors.newFixedThreadPool(16);
+        try {
+            final List<Future<?>> futures = new ArrayList<>();
+            for (int i = 0; i < 256; i++) {
+                // request an index input and immediately close it
+                final String blobname = "blob-" + randomIntBetween(0, 7);
+                futures.add(testRunner.submit(() -> {
+                    try {
+                        try (IndexInput indexInput = fetchBlobWithName(blobname)) {
+                            assertIndexInputIsFunctional(indexInput);
+                        }
+                    } catch (Exception e) {
+                        throw new AssertionError(e);
+                    }
+                }));
+            }
+            // Wait for all threads to complete
+            for (Future<?> future : futures) {
+                future.get(10, TimeUnit.SECONDS);
+            }
+        } finally {
+            assertTrue(terminate(testRunner));
+        }
+        MatcherAssert.assertThat("Expected many evictions to happen", fileCache.stats().evictionCount(), greaterThan(0L));
+    }
+
+    public void testUsageExceedsCapacity() throws Exception {
+        // Fetch resources that exceed the configured capacity of the cache and assert that the
+        // returned IndexInputs are still functional.
+        try (IndexInput i1 = fetchBlobWithName("1"); IndexInput i2 = fetchBlobWithName("2"); IndexInput i3 = fetchBlobWithName("3")) {
+            assertIndexInputIsFunctional(i1);
+            assertIndexInputIsFunctional(i2);
+            assertIndexInputIsFunctional(i3);
+            MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo((long) EIGHT_MB * 3));
+            MatcherAssert.assertThat(fileCache.usage().usage(), equalTo((long) EIGHT_MB * 3));
+        }
+        MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo(0L));
+        MatcherAssert.assertThat(fileCache.usage().usage(), equalTo((long) EIGHT_MB * 3));
+        // Fetch another resource which will trigger an eviction
+        try (IndexInput i1 = fetchBlobWithName("1")) {
+            assertIndexInputIsFunctional(i1);
+            MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo((long) EIGHT_MB));
+            MatcherAssert.assertThat(fileCache.usage().usage(), equalTo((long) EIGHT_MB));
+        }
+        MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo(0L));
+        MatcherAssert.assertThat(fileCache.usage().usage(), equalTo((long) EIGHT_MB));
+    }
+
+    public void testDownloadFails() throws Exception {
+        doThrow(new IOException("Expected test exception")).when(blobContainer).readBlob(eq("failure-blob"), anyLong(), anyLong());
+        expectThrows(
+            IOException.class,
+            () -> transferManager.fetchBlob(
+                BlobFetchRequest.builder()
+                    .blobName("failure-blob")
+                    .position(0)
+                    .fileName("file")
+                    .directory(directory)
+                    .length(EIGHT_MB)
+                    .build()
+            )
+        );
+        MatcherAssert.assertThat(fileCache.usage().activeUsage(), equalTo(0L));
+        MatcherAssert.assertThat(fileCache.usage().usage(), equalTo(0L));
+    }
+
+    public void testFetchesToDifferentBlobsDoNotBlockOnEachOther() throws Exception {
+        // Mock a call for a blob that will block until the latch is released,
+        // then start the fetch for that blob on a separate thread
+        final CountDownLatch latch = new CountDownLatch(1);
+        doAnswer(i -> {
+            latch.await();
+            return new ByteArrayInputStream(createData());
+        }).when(blobContainer).readBlob(eq("blocking-blob"), anyLong(), anyLong());
+        final Thread blockingThread = new Thread(() -> {
+            try {
+                transferManager.fetchBlob(
+                    BlobFetchRequest.builder()
+                        .blobName("blocking-blob")
+                        .position(0)
+                        .fileName("blocking-file")
+                        .directory(directory)
+                        .length(EIGHT_MB)
+                        .build()
+                );
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        blockingThread.start();
+
+        // Assert that a different blob can be fetched and will not block on the first blob
+        try (IndexInput i = fetchBlobWithName("file")) {
+            assertIndexInputIsFunctional(i);
+        }
+
+        assertTrue(blockingThread.isAlive());
+        latch.countDown();
+        blockingThread.join(5_000);
+        assertFalse(blockingThread.isAlive());
+    }
+
+    private IndexInput fetchBlobWithName(String blobname) throws IOException {
+        return transferManager.fetchBlob(
+            BlobFetchRequest.builder().blobName("blob").position(0).fileName(blobname).directory(directory).length(EIGHT_MB).build()
+        );
+    }
+
+    private static void assertIndexInputIsFunctional(IndexInput indexInput) throws IOException {
+        indexInput.seek(EIGHT_MB - 1);
+        MatcherAssert.assertThat(indexInput.readByte(), equalTo((byte) 7));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/utils/cache/LRUCacheTests.java b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/LRUCacheTests.java
new file mode 100644
index 0000000000000..47cb8000b6c83
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/LRUCacheTests.java
@@ -0,0 +1,15 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+public class LRUCacheTests extends RefCountedCacheTestCase {
+    public LRUCacheTests() {
+        super(new LRUCache<>(CAPACITY, n -> {}, value -> value));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/utils/cache/RefCountedCacheTestCase.java b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/RefCountedCacheTestCase.java
new file mode 100644
index 0000000000000..b11740b53e11f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/RefCountedCacheTestCase.java
@@ -0,0 +1,218 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+abstract class RefCountedCacheTestCase extends OpenSearchTestCase {
+    static final int CAPACITY = 100;
+
+    private final RefCountedCache<String, Long> refCountedCache;
+
+    protected RefCountedCacheTestCase(RefCountedCache<String, Long> refCountedCache) {
+        this.refCountedCache = refCountedCache;
+    }
+
+    public void testBasicGetAndPutAndRemove() {
+        assertNull(refCountedCache.get("1"));
+        refCountedCache.put("1", 10L);
+        assertEquals(10L, (long) refCountedCache.get("1"));
+        refCountedCache.remove("1");
+        assertNull(refCountedCache.get("1"));
+    }
+
+    public void testUsageWithIncrementAndDecrement() {
+        refCountedCache.put("1", 10L);
+        assertEquals(10L, refCountedCache.usage().usage());
+        assertEquals(10L, refCountedCache.usage().activeUsage());
+
+        refCountedCache.decRef("1");
+        assertEquals(10L, refCountedCache.usage().usage());
+        assertEquals(0L, refCountedCache.usage().activeUsage());
+
+        refCountedCache.incRef("1");
+        assertEquals(10L, refCountedCache.usage().usage());
+        assertEquals(10L, refCountedCache.usage().activeUsage());
+    }
+
+    public void testEviction() {
+        for (int i = 1; i <= 5; i++) {
+            final String key = Integer.toString(i);
+            refCountedCache.put(key, 25L);
+            refCountedCache.decRef(key);
+        }
+        assertNull(refCountedCache.get("1"));
+        assertNull(refCountedCache.get("2"));
+        assertNotNull(refCountedCache.get("3"));
+        assertNotNull(refCountedCache.get("4"));
+        assertNotNull(refCountedCache.get("5"));
+
+        assertEquals(75L, refCountedCache.usage().usage());
+        assertEquals(75L, refCountedCache.usage().activeUsage());
+    }
+
+    public void testComputeRemoveWhenExists() {
+        refCountedCache.put("1", 25L);
+        refCountedCache.decRef("1");
+        assertEquals(0, refCountedCache.usage().activeUsage());
+        assertEquals(25L, refCountedCache.usage().usage());
+
+        assertNull(refCountedCache.compute("1", (k, v) -> null));
+        assertNull(refCountedCache.get("1"));
+        assertEquals(0, refCountedCache.usage().activeUsage());
+        assertEquals(0L, refCountedCache.usage().usage());
+    }
+
+    public void testComputeRemoveWhenNotExists() {
+        assertUsage(0, 0);
+        assertNull(refCountedCache.compute("1", (k, v) -> null));
+        assertNull(refCountedCache.get("1"));
+        assertUsage(0, 0);
+    }
+
+    public void testComputeRemapExists() {
+        assertUsage(0, 0);
+        refCountedCache.put("1", 25L);
+        refCountedCache.decRef("1");
+        assertUsage(25, 0);
+
+        final long newValue = refCountedCache.compute("1", (k, v) -> v + 5);
+        assertEquals(30L, newValue);
+        assertUsage(30, 30);
+
+        refCountedCache.decRef("1");
+        assertUsage(30, 0);
+
+        assertEquals(30L, (long) refCountedCache.get("1"));
+    }
+
+    public void testComputeRemapNotExists() {
+        assertUsage(0, 0);
+        final long newValue = refCountedCache.compute("1", (k, v) -> 30L);
+        assertEquals(30L, newValue);
+        assertUsage(30, 30);
+
+        refCountedCache.decRef("1");
+        assertUsage(30, 0);
+
+        assertEquals(30L, (long) refCountedCache.get("1"));
+    }
+
+    public void testActiveUsageGreaterThanCapacity() {
+        for (int i = 1; i <= 5; i++) {
+            final String key = Integer.toString(i);
+            refCountedCache.put(key, 25L);
+        }
+        assertEquals(125L, refCountedCache.usage().usage());
+        assertEquals(125L, refCountedCache.usage().activeUsage());
+    }
+
+    public void testReferenceCountingItemsThatDoNotExist() {
+        assertNull(refCountedCache.get("1"));
+        assertUsage(0, 0);
+        refCountedCache.incRef("1");
+        assertNull(refCountedCache.get("1"));
+        assertUsage(0, 0);
+        refCountedCache.decRef("1");
+        assertNull(refCountedCache.get("1"));
+        assertEquals(0L, refCountedCache.usage().usage());
+        assertEquals(0L, refCountedCache.usage().activeUsage());
+    }
+
+    public void testPrune() {
+        refCountedCache.put("1", 10L);
+        refCountedCache.decRef("1");
+        refCountedCache.put("2", 10L);
+        refCountedCache.decRef("2");
+        refCountedCache.put("3", 10L);
+
+        assertEquals(20L, refCountedCache.prune());
+        assertNull(refCountedCache.get("1"));
+        assertNull(refCountedCache.get("2"));
+        assertEquals(10L, (long) refCountedCache.get("3"));
+    }
+
+    public void testPruneWithPredicate() {
+        refCountedCache.put("1", 10L);
+        refCountedCache.decRef("1");
+        refCountedCache.put("2", 10L);
+        refCountedCache.decRef("2");
+        refCountedCache.put("3", 10L);
+
+        assertEquals(0L, refCountedCache.prune(path -> false));
+
+        assertEquals(20L, refCountedCache.prune(path -> true));
+        assertNull(refCountedCache.get("1"));
+        assertNull(refCountedCache.get("2"));
+        assertEquals(10L, (long) refCountedCache.get("3"));
+    }
+
+    public void testStats() {
+        assertEquals(0, refCountedCache.stats().hitCount());
+        refCountedCache.put("1", 1L);
+        refCountedCache.get("1");
+        assertEquals(1, refCountedCache.stats().hitCount());
+
+        assertEquals(0, refCountedCache.stats().replaceCount());
+        refCountedCache.put("1", 2L);
+        assertEquals(1, refCountedCache.stats().replaceCount());
+        assertEquals(1, refCountedCache.stats().hitCount());
+
+        assertEquals(0, refCountedCache.stats().evictionCount());
+        refCountedCache.put("2", 80L);
+        refCountedCache.decRef("2");
+        refCountedCache.put("3", 80L);
+        assertEquals(1, refCountedCache.stats().evictionCount());
+
+        assertEquals(0, refCountedCache.stats().missCount());
+        assertNull(refCountedCache.get("2"));
+        assertEquals(1, refCountedCache.stats().missCount());
+
+        assertEquals(0, refCountedCache.stats().removeCount());
+        refCountedCache.remove("3");
+        assertEquals(1, refCountedCache.stats().removeCount());
+    }
+
+    public void testComputeStats() {
+        refCountedCache.compute("1", (k, v) -> null);
+        assertEquals(0, refCountedCache.stats().missCount());
+        assertEquals(0, refCountedCache.stats().hitCount());
+        assertEquals(0, refCountedCache.stats().replaceCount());
+        assertEquals(0, refCountedCache.stats().removeCount());
+
+        refCountedCache.compute("1", (k, v) -> 10L);
+        assertEquals(1, refCountedCache.stats().missCount());
+        assertEquals(0, refCountedCache.stats().hitCount());
+        assertEquals(0, refCountedCache.stats().replaceCount());
+        assertEquals(0, refCountedCache.stats().removeCount());
+
+        refCountedCache.compute("1", (k, v) -> 10L);
+        assertEquals(1, refCountedCache.stats().missCount());
+        assertEquals(1, refCountedCache.stats().hitCount());
+        assertEquals(0, refCountedCache.stats().replaceCount());
+        assertEquals(0, refCountedCache.stats().removeCount());
+
+        refCountedCache.compute("1", (k, v) -> 20L);
+        assertEquals(1, refCountedCache.stats().missCount());
+        assertEquals(2, refCountedCache.stats().hitCount());
+        assertEquals(1, refCountedCache.stats().replaceCount());
+        assertEquals(0, refCountedCache.stats().removeCount());
+
+        refCountedCache.compute("1", (k, v) -> null);
+        assertEquals(1, refCountedCache.stats().missCount());
+        assertEquals(2, refCountedCache.stats().hitCount());
+        assertEquals(1, refCountedCache.stats().replaceCount());
+        assertEquals(1, refCountedCache.stats().removeCount());
+    }
+
+    private void assertUsage(long usage, long activeUsage) {
+        assertEquals(usage, refCountedCache.usage().usage());
+        assertEquals(activeUsage, refCountedCache.usage().activeUsage());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/store/remote/utils/cache/SegmentedCacheTests.java b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/SegmentedCacheTests.java
new file mode 100644
index 0000000000000..4081bf4d61907
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/store/remote/utils/cache/SegmentedCacheTests.java
@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.store.remote.utils.cache;
+
+public class SegmentedCacheTests extends RefCountedCacheTestCase {
+    public SegmentedCacheTests() {
+        super(
+            SegmentedCache.<String, Long>builder().capacity(CAPACITY).weigher(value -> value).listener(n -> {}).concurrencyLevel(1).build()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/suggest/stats/CompletionsStatsTests.java b/server/src/test/java/org/opensearch/index/suggest/stats/CompletionsStatsTests.java
index 6d193bd9af4ac..104f132fb47ce 100644
--- a/server/src/test/java/org/opensearch/index/suggest/stats/CompletionsStatsTests.java
+++ b/server/src/test/java/org/opensearch/index/suggest/stats/CompletionsStatsTests.java
@@ -34,7 +34,7 @@
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.FieldMemoryStatsTests;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.suggest.completion.CompletionStats;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/index/termvectors/TermVectorsServiceTests.java b/server/src/test/java/org/opensearch/index/termvectors/TermVectorsServiceTests.java
index 60694c7d6d61a..37b672dc064c4 100644
--- a/server/src/test/java/org/opensearch/index/termvectors/TermVectorsServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/termvectors/TermVectorsServiceTests.java
@@ -38,7 +38,7 @@
 import org.opensearch.action.termvectors.TermVectorsRequest;
 import org.opensearch.action.termvectors.TermVectorsResponse;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
diff --git a/server/src/test/java/org/opensearch/index/translog/InternalTranslogManagerTests.java b/server/src/test/java/org/opensearch/index/translog/InternalTranslogManagerTests.java
new file mode 100644
index 0000000000000..c098d11a3487f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/InternalTranslogManagerTests.java
@@ -0,0 +1,293 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.mapper.ParsedDocument;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.listener.TranslogEventListener;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static org.opensearch.index.seqno.SequenceNumbers.NO_OPS_PERFORMED;
+import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
+import static org.hamcrest.Matchers.equalTo;
+
+public class InternalTranslogManagerTests extends TranslogManagerTestCase {
+
+    public void testRecoveryFromTranslog() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final AtomicBoolean beginTranslogRecoveryInvoked = new AtomicBoolean(false);
+        final AtomicBoolean onTranslogRecoveryInvoked = new AtomicBoolean(false);
+        InternalTranslogManager translogManager = null;
+
+        LocalCheckpointTracker tracker = new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED);
+        try {
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> tracker,
+                translogUUID,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER,
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            final int docs = randomIntBetween(1, 100);
+            for (int i = 0; i < docs; i++) {
+                final String id = Integer.toString(i);
+                final ParsedDocument doc = testParsedDocument(id, null, testDocumentWithTextField(), SOURCE, null);
+                Engine.Index index = indexForDoc(doc);
+                Engine.IndexResult indexResult = new Engine.IndexResult(index.version(), index.primaryTerm(), i, true);
+                tracker.markSeqNoAsProcessed(i);
+                translogManager.add(new Translog.Index(index, indexResult));
+                translogManager.rollTranslogGeneration();
+            }
+            long maxSeqNo = tracker.getMaxSeqNo();
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().getUncommittedOperations());
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().estimatedNumberOfOperations());
+
+            translogManager.syncTranslog();
+            translogManager.close();
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED),
+                translogUUID,
+                new TranslogEventListener() {
+                    @Override
+                    public void onAfterTranslogRecovery() {
+                        onTranslogRecoveryInvoked.set(true);
+                    }
+
+                    @Override
+                    public void onBeginTranslogRecovery() {
+                        beginTranslogRecoveryInvoked.set(true);
+                    }
+                },
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            AtomicInteger opsRecovered = new AtomicInteger();
+            int opsRecoveredFromTranslog = translogManager.recoverFromTranslog((snapshot) -> {
+                Translog.Operation operation;
+                while ((operation = snapshot.next()) != null) {
+                    opsRecovered.incrementAndGet();
+                }
+                return opsRecovered.get();
+            }, NO_OPS_PERFORMED, Long.MAX_VALUE);
+
+            assertEquals(maxSeqNo + 1, opsRecovered.get());
+            assertEquals(maxSeqNo + 1, opsRecoveredFromTranslog);
+
+            assertTrue(beginTranslogRecoveryInvoked.get());
+            assertTrue(onTranslogRecoveryInvoked.get());
+
+        } finally {
+            translogManager.close();
+        }
+    }
+
+    public void testTranslogRollsGeneration() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        InternalTranslogManager translogManager = null;
+        LocalCheckpointTracker tracker = new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED);
+        try {
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> tracker,
+                translogUUID,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER,
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            final int docs = randomIntBetween(1, 100);
+            for (int i = 0; i < docs; i++) {
+                final String id = Integer.toString(i);
+                final ParsedDocument doc = testParsedDocument(id, null, testDocumentWithTextField(), SOURCE, null);
+                Engine.Index index = indexForDoc(doc);
+                Engine.IndexResult indexResult = new Engine.IndexResult(index.version(), index.primaryTerm(), i, true);
+                tracker.markSeqNoAsProcessed(i);
+                translogManager.add(new Translog.Index(index, indexResult));
+                translogManager.rollTranslogGeneration();
+            }
+            long maxSeqNo = tracker.getMaxSeqNo();
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().getUncommittedOperations());
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().estimatedNumberOfOperations());
+
+            translogManager.syncTranslog();
+            translogManager.close();
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED),
+                translogUUID,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER,
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            AtomicInteger opsRecovered = new AtomicInteger();
+            int opsRecoveredFromTranslog = translogManager.recoverFromTranslog((snapshot) -> {
+                Translog.Operation operation;
+                while ((operation = snapshot.next()) != null) {
+                    opsRecovered.incrementAndGet();
+                }
+                return opsRecovered.get();
+            }, NO_OPS_PERFORMED, Long.MAX_VALUE);
+
+            assertEquals(maxSeqNo + 1, opsRecovered.get());
+            assertEquals(maxSeqNo + 1, opsRecoveredFromTranslog);
+        } finally {
+            translogManager.close();
+        }
+    }
+
+    public void testTrimOperationsFromTranslog() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        InternalTranslogManager translogManager = null;
+        LocalCheckpointTracker tracker = new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED);
+        try {
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> tracker,
+                translogUUID,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER,
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            final int docs = randomIntBetween(1, 100);
+            for (int i = 0; i < docs; i++) {
+                final String id = Integer.toString(i);
+                final ParsedDocument doc = testParsedDocument(id, null, testDocumentWithTextField(), SOURCE, null);
+                Engine.Index index = indexForDoc(doc);
+                Engine.IndexResult indexResult = new Engine.IndexResult(index.version(), index.primaryTerm(), i, true);
+                tracker.markSeqNoAsProcessed(i);
+                translogManager.add(new Translog.Index(index, indexResult));
+            }
+            long maxSeqNo = tracker.getMaxSeqNo();
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().getUncommittedOperations());
+            assertEquals(maxSeqNo + 1, translogManager.getTranslogStats().estimatedNumberOfOperations());
+
+            primaryTerm.set(randomLongBetween(primaryTerm.get(), Long.MAX_VALUE));
+            translogManager.rollTranslogGeneration();
+            translogManager.trimOperationsFromTranslog(primaryTerm.get(), NO_OPS_PERFORMED); // trim everything in translog
+
+            translogManager.close();
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> new LocalCheckpointTracker(NO_OPS_PERFORMED, NO_OPS_PERFORMED),
+                translogUUID,
+                TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER,
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            AtomicInteger opsRecovered = new AtomicInteger();
+            int opsRecoveredFromTranslog = translogManager.recoverFromTranslog((snapshot) -> {
+                Translog.Operation operation;
+                while ((operation = snapshot.next()) != null) {
+                    opsRecovered.incrementAndGet();
+                }
+                return opsRecovered.get();
+            }, NO_OPS_PERFORMED, Long.MAX_VALUE);
+
+            assertEquals(0, opsRecovered.get());
+            assertEquals(0, opsRecoveredFromTranslog);
+        } finally {
+            translogManager.close();
+        }
+    }
+
+    public void testTranslogSync() throws IOException {
+        final AtomicLong globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        AtomicBoolean syncListenerInvoked = new AtomicBoolean();
+        InternalTranslogManager translogManager = null;
+        final AtomicInteger maxSeqNo = new AtomicInteger(randomIntBetween(0, 128));
+        final AtomicInteger localCheckpoint = new AtomicInteger(randomIntBetween(0, maxSeqNo.get()));
+        try {
+            ParsedDocument doc = testParsedDocument("1", null, testDocumentWithTextField(), B_1, null);
+            AtomicReference<InternalTranslogManager> translogManagerAtomicReference = new AtomicReference<>();
+            translogManager = new InternalTranslogManager(
+                new TranslogConfig(shardId, primaryTranslogDir, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, ""),
+                primaryTerm,
+                globalCheckpoint::get,
+                createTranslogDeletionPolicy(INDEX_SETTINGS),
+                shardId,
+                new ReleasableLock(new ReentrantReadWriteLock().readLock()),
+                () -> new LocalCheckpointTracker(maxSeqNo.get(), localCheckpoint.get()),
+                translogUUID,
+                new TranslogEventListener() {
+                    @Override
+                    public void onAfterTranslogSync() {
+                        try {
+                            translogManagerAtomicReference.get().trimUnreferencedReaders();
+                            syncListenerInvoked.set(true);
+                        } catch (IOException ex) {
+                            fail("Failed due to " + ex);
+                        }
+                    }
+                },
+                () -> {},
+                new InternalTranslogFactory(),
+                () -> Boolean.TRUE
+            );
+            translogManagerAtomicReference.set(translogManager);
+            Engine.Index index = indexForDoc(doc);
+            Engine.IndexResult indexResult = new Engine.IndexResult(index.version(), index.primaryTerm(), 1, false);
+            translogManager.add(new Translog.Index(index, indexResult));
+
+            translogManager.syncTranslog();
+
+            assertThat(translogManager.getTranslog().currentFileGeneration(), equalTo(2L));
+            assertThat(translogManager.getTranslog().getMinFileGeneration(), equalTo(2L));
+            assertTrue(syncListenerInvoked.get());
+        } finally {
+            translogManager.close();
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/LocalTranslogTests.java b/server/src/test/java/org/opensearch/index/translog/LocalTranslogTests.java
new file mode 100644
index 0000000000000..f725783c50e52
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/LocalTranslogTests.java
@@ -0,0 +1,4114 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.index.translog;
+
+import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.backward_codecs.store.EndiannessReverserUtil;
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.IndexFormatTooOldException;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.apache.lucene.store.ByteArrayDataOutput;
+import org.apache.lucene.store.DataOutput;
+import org.apache.lucene.tests.mockfile.FilterFileChannel;
+import org.apache.lucene.tests.mockfile.FilterFileSystemProvider;
+import org.apache.lucene.tests.store.MockDirectoryWrapper;
+import org.apache.lucene.tests.util.LineFileDocs;
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.Randomness;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.bytes.ReleasableBytesReference;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.common.util.concurrent.ReleasableLock;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.Assertions;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.VersionType;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.Engine.Operation.Origin;
+import org.opensearch.index.engine.MissingHistoryOperationsException;
+import org.opensearch.index.mapper.IdFieldMapper;
+import org.opensearch.index.mapper.ParseContext.Document;
+import org.opensearch.index.mapper.ParsedDocument;
+import org.opensearch.index.mapper.SeqNoFieldMapper;
+import org.opensearch.index.mapper.Uid;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.seqno.LocalCheckpointTrackerTests;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.Translog.Location;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.VersionUtils;
+import org.hamcrest.Matchers;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.Closeable;
+import java.io.EOFException;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.CopyOption;
+import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.Phaser;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.LongConsumer;
+import java.util.function.LongSupplier;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+
+import static org.opensearch.common.util.BigArrays.NON_RECYCLING_INSTANCE;
+import static org.opensearch.index.translog.SnapshotMatchers.containsOperationsInAnyOrder;
+import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
+import static org.hamcrest.CoreMatchers.hasItem;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.endsWith;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasToString;
+import static org.hamcrest.Matchers.in;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+@LuceneTestCase.SuppressFileSystems("ExtrasFS")
+public class LocalTranslogTests extends OpenSearchTestCase {
+
+    protected final ShardId shardId = new ShardId("index", "_na_", 1);
+
+    protected Translog translog;
+    private AtomicLong globalCheckpoint;
+    protected Path translogDir;
+    // A default primary term is used by translog instances created in this test.
+    private final AtomicLong primaryTerm = new AtomicLong();
+    private final AtomicReference<LongConsumer> persistedSeqNoConsumer = new AtomicReference<>();
+    private boolean expectIntactTranslog;
+
+    @Before
+    public void expectIntactTranslogByDefault() {
+        expectIntactTranslog = true;
+    }
+
+    @Override
+    protected void afterIfSuccessful() throws Exception {
+        super.afterIfSuccessful();
+
+        if (translog.isOpen()) {
+            if (translog.currentFileGeneration() > 1) {
+                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(Long.MAX_VALUE);
+                translog.trimUnreferencedReaders();
+                assertFileDeleted(translog, translog.currentFileGeneration() - 1);
+            }
+            translog.close();
+        }
+        if (expectIntactTranslog) {
+            assertFileIsPresent(translog, translog.currentFileGeneration());
+        }
+        IOUtils.rm(translog.location()); // delete all the locations
+
+    }
+
+    private LongConsumer getPersistedSeqNoConsumer() {
+        return seqNo -> {
+            final LongConsumer consumer = persistedSeqNoConsumer.get();
+            if (consumer != null) {
+                consumer.accept(seqNo);
+            }
+        };
+    }
+
+    protected Translog createTranslog(TranslogConfig config) throws IOException {
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            primaryTerm.get()
+        );
+        return new LocalTranslog(
+            config,
+            translogUUID,
+            createTranslogDeletionPolicy(config.getIndexSettings()),
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            getPersistedSeqNoConsumer()
+        );
+    }
+
+    protected Translog openTranslog(TranslogConfig config, String translogUUID) throws IOException {
+        return new LocalTranslog(
+            config,
+            translogUUID,
+            createTranslogDeletionPolicy(config.getIndexSettings()),
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            getPersistedSeqNoConsumer()
+        );
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        primaryTerm.set(randomLongBetween(1, Integer.MAX_VALUE));
+        // if a previous test failed we clean up things here
+        translogDir = createTempDir();
+        translog = create(translogDir);
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        try {
+            translog.getDeletionPolicy().assertNoOpenTranslogRefs();
+            translog.close();
+        } finally {
+            super.tearDown();
+        }
+    }
+
+    private Translog create(Path path) throws IOException {
+        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final TranslogConfig translogConfig = getTranslogConfig(path);
+        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(translogConfig.getIndexSettings());
+        final String translogUUID = Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
+        return new LocalTranslog(
+            translogConfig,
+            translogUUID,
+            deletionPolicy,
+            () -> globalCheckpoint.get(),
+            primaryTerm::get,
+            getPersistedSeqNoConsumer()
+        );
+    }
+
+    private TranslogConfig getTranslogConfig(final Path path) {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            // only randomize between nog age retention and a long one, so failures will have a chance of reproducing
+            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_AGE_SETTING.getKey(), randomBoolean() ? "-1ms" : "1h")
+            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_SIZE_SETTING.getKey(), randomIntBetween(-1, 2048) + "b")
+            .build();
+        return getTranslogConfig(path, settings);
+    }
+
+    private TranslogConfig getTranslogConfig(final Path path, final Settings settings) {
+        final ByteSizeValue bufferSize = randomFrom(
+            TranslogConfig.DEFAULT_BUFFER_SIZE,
+            new ByteSizeValue(8, ByteSizeUnit.KB),
+            new ByteSizeValue(10 + randomInt(128 * 1024), ByteSizeUnit.BYTES)
+        );
+
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(shardId.getIndex(), settings);
+        return new TranslogConfig(shardId, path, indexSettings, NON_RECYCLING_INSTANCE, bufferSize, "");
+    }
+
+    private Location addToTranslogAndList(Translog translog, List<Translog.Operation> list, Translog.Operation op) throws IOException {
+        list.add(op);
+        return translog.add(op);
+    }
+
+    public void testIdParsingFromFile() {
+        long id = randomIntBetween(0, Integer.MAX_VALUE);
+        Path file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id + ".tlog");
+        assertThat(Translog.parseIdFromFileName(file), equalTo(id));
+
+        id = randomIntBetween(0, Integer.MAX_VALUE);
+        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id);
+        try {
+            Translog.parseIdFromFileName(file);
+            fail("invalid pattern");
+        } catch (IllegalArgumentException ex) {
+            // all good
+        }
+
+        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id + ".recovering");
+        try {
+            Translog.parseIdFromFileName(file);
+            fail("invalid pattern");
+        } catch (IllegalArgumentException ex) {
+            // all good
+        }
+
+        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + randomNonTranslogPatternString(1, 10) + id);
+        try {
+            Translog.parseIdFromFileName(file);
+            fail("invalid pattern");
+        } catch (IllegalArgumentException ex) {
+            // all good
+        }
+        file = translogDir.resolve(randomNonTranslogPatternString(1, Translog.TRANSLOG_FILE_PREFIX.length() - 1));
+        try {
+            Translog.parseIdFromFileName(file);
+            fail("invalid pattern");
+        } catch (IllegalArgumentException ex) {
+            // all good
+        }
+    }
+
+    private String randomNonTranslogPatternString(int min, int max) {
+        String string;
+        boolean validPathString;
+        do {
+            validPathString = false;
+            string = randomRealisticUnicodeOfCodepointLength(randomIntBetween(min, max));
+            try {
+                final Path resolved = translogDir.resolve(string);
+                // some strings (like '/' , '..') do not refer to a file, which we this method should return
+                validPathString = resolved.getFileName() != null;
+            } catch (InvalidPathException ex) {
+                // some FS don't like our random file names -- let's just skip these random choices
+            }
+        } while (Translog.PARSE_STRICT_ID_PATTERN.matcher(string).matches() || validPathString == false);
+        return string;
+    }
+
+    public void testSimpleOperations() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+        }
+
+        addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        addToTranslogAndList(translog, ops, new Translog.Delete("2", 1, primaryTerm.get()));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        final long seqNo = randomLongBetween(0, Integer.MAX_VALUE);
+        final String reason = randomAlphaOfLength(16);
+        final long noopTerm = randomLongBetween(1, primaryTerm.get());
+        addToTranslogAndList(translog, ops, new Translog.NoOp(seqNo, noopTerm, reason));
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+
+            Translog.Index index = (Translog.Index) snapshot.next();
+            assertNotNull(index);
+            assertThat(BytesReference.toBytes(index.source()), equalTo(new byte[] { 1 }));
+
+            Translog.Delete delete = (Translog.Delete) snapshot.next();
+            assertNotNull(delete);
+            assertThat(delete.id(), equalTo("2"));
+
+            Translog.NoOp noOp = (Translog.NoOp) snapshot.next();
+            assertNotNull(noOp);
+            assertThat(noOp.seqNo(), equalTo(seqNo));
+            assertThat(noOp.primaryTerm(), equalTo(noopTerm));
+            assertThat(noOp.reason(), equalTo(reason));
+
+            assertNull(snapshot.next());
+        }
+
+        long firstId = translog.currentFileGeneration();
+        translog.rollGeneration();
+        assertThat(translog.currentFileGeneration(), Matchers.not(equalTo(firstId)));
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot(seqNo + 1, randomLongBetween(seqNo + 1, Long.MAX_VALUE))) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+            assertThat(snapshot.totalOperations(), equalTo(0));
+        }
+    }
+
+    protected TranslogStats stats() throws IOException {
+        // force flushing and updating of stats
+        translog.sync();
+        TranslogStats stats = translog.stats();
+        if (randomBoolean()) {
+            BytesStreamOutput out = new BytesStreamOutput();
+            stats.writeTo(out);
+            StreamInput in = out.bytes().streamInput();
+            stats = new TranslogStats(in);
+        }
+        return stats;
+    }
+
+    public void testFindEarliestLastModifiedAge() throws IOException {
+        final int numberOfReaders = scaledRandomIntBetween(1, 10);
+        long fixedTime = randomLongBetween(0, 10000000000000000L);
+        long[] periods = new long[numberOfReaders + 1];
+        long period = randomLongBetween(10000, 1000000);
+        periods[numberOfReaders] = period;
+        TranslogWriter w = mock(TranslogWriter.class);
+        when(w.getLastModifiedTime()).thenReturn(fixedTime - period);
+        assertThat(Translog.findEarliestLastModifiedAge(fixedTime, new ArrayList<>(), w), equalTo(period));
+
+        for (int i = 0; i < numberOfReaders; i++) {
+            periods[i] = randomLongBetween(10000, 1000000);
+        }
+        List<TranslogReader> readers = new ArrayList<>();
+        for (long l : periods) {
+            TranslogReader r = mock(TranslogReader.class);
+            when(r.getLastModifiedTime()).thenReturn(fixedTime - l);
+            readers.add(r);
+        }
+        assertThat(Translog.findEarliestLastModifiedAge(fixedTime, readers, w), equalTo(LongStream.of(periods).max().orElse(0L)));
+    }
+
+    public void testStats() throws IOException {
+        // self control cleaning for test
+        translog.getDeletionPolicy().setRetentionSizeInBytes(1024 * 1024);
+        translog.getDeletionPolicy().setRetentionAgeInMillis(3600 * 1000);
+        final long firstOperationPosition = translog.getFirstOperationPosition();
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(0));
+        }
+        assertThat((int) firstOperationPosition, greaterThan(CodecUtil.headerLength(TranslogHeader.TRANSLOG_CODEC)));
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(1));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(157L));
+            assertThat(stats.getUncommittedOperations(), equalTo(1));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(102L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
+        }
+
+        translog.add(new Translog.Delete("2", 1, primaryTerm.get()));
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(2));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(193L));
+            assertThat(stats.getUncommittedOperations(), equalTo(2));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(138L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
+        }
+
+        translog.add(new Translog.Delete("3", 2, primaryTerm.get()));
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(3));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(229L));
+            assertThat(stats.getUncommittedOperations(), equalTo(3));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(174L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
+        }
+
+        translog.add(new Translog.NoOp(3, 1, randomAlphaOfLength(16)));
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(271L));
+            assertThat(stats.getUncommittedOperations(), equalTo(4));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(216L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
+        }
+
+        translog.rollGeneration();
+        {
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(326L));
+            assertThat(stats.getUncommittedOperations(), equalTo(4));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(271L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
+        }
+
+        {
+            final TranslogStats stats = stats();
+            final BytesStreamOutput out = new BytesStreamOutput();
+            stats.writeTo(out);
+            final TranslogStats copy = new TranslogStats(out.bytes().streamInput());
+            assertThat(copy.estimatedNumberOfOperations(), equalTo(4));
+            assertThat(copy.getTranslogSizeInBytes(), equalTo(326L));
+
+            try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+                builder.startObject();
+                copy.toXContent(builder, ToXContent.EMPTY_PARAMS);
+                builder.endObject();
+                assertEquals(
+                    "{\"translog\":{\"operations\":4,\"size_in_bytes\":"
+                        + 326
+                        + ",\"uncommitted_operations\":4,\"uncommitted_size_in_bytes\":"
+                        + 271
+                        + ",\"earliest_last_modified_age\":"
+                        + stats.getEarliestLastModifiedAge()
+                        + ",\"remote_store\":{\"upload\":{"
+                        + "\"total_uploads\":{\"started\":0,\"failed\":0,\"succeeded\":0},"
+                        + "\"total_upload_size\":{\"started_bytes\":0,\"failed_bytes\":0,\"succeeded_bytes\":0}"
+                        + "}}}}",
+                    builder.toString()
+                );
+            }
+        }
+        translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(randomLongBetween(3, Long.MAX_VALUE));
+        translog.trimUnreferencedReaders();
+        {
+            long lastModifiedAge = System.currentTimeMillis() - translog.getCurrent().getLastModifiedTime();
+            final TranslogStats stats = stats();
+            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
+            assertThat(stats.getTranslogSizeInBytes(), equalTo(326L));
+            assertThat(stats.getUncommittedOperations(), equalTo(0));
+            assertThat(stats.getUncommittedSizeInBytes(), equalTo(firstOperationPosition));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
+        }
+    }
+
+    public void testUncommittedOperations() throws Exception {
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        deletionPolicy.setRetentionAgeInMillis(randomLong());
+        deletionPolicy.setRetentionSizeInBytes(randomLong());
+
+        final int operations = scaledRandomIntBetween(10, 100);
+        int uncommittedOps = 0;
+        int operationsInLastGen = 0;
+        for (int i = 0; i < operations; i++) {
+            translog.add(new Translog.Index(Integer.toString(i), i, primaryTerm.get(), new byte[] { 1 }));
+            uncommittedOps++;
+            operationsInLastGen++;
+            if (rarely()) {
+                translog.rollGeneration();
+                operationsInLastGen = 0;
+            }
+            assertThat(translog.stats().getUncommittedOperations(), equalTo(uncommittedOps));
+            if (frequently()) {
+                deletionPolicy.setLocalCheckpointOfSafeCommit(i);
+                assertThat(translog.stats().getUncommittedOperations(), equalTo(operationsInLastGen));
+                uncommittedOps = operationsInLastGen;
+            }
+        }
+    }
+
+    public void testTotalTests() {
+        final TranslogStats total = new TranslogStats();
+
+        assertThat(total.estimatedNumberOfOperations(), equalTo(0));
+        assertThat(total.getTranslogSizeInBytes(), equalTo(0L));
+        assertThat(total.getUncommittedOperations(), equalTo(0));
+        assertThat(total.getUncommittedSizeInBytes(), equalTo(0L));
+        assertThat(total.getEarliestLastModifiedAge(), equalTo(0L));
+
+        final int n = randomIntBetween(1, 16);
+        final List<TranslogStats> statsList = new ArrayList<>(n);
+        long earliestLastModifiedAge = Long.MAX_VALUE;
+        for (int i = 0; i < n; i++) {
+            final TranslogStats stats = new TranslogStats(
+                randomIntBetween(1, 4096),
+                randomIntBetween(1, 1 << 20),
+                randomIntBetween(1, 1 << 20),
+                randomIntBetween(1, 4096),
+                randomIntBetween(1, 1 << 20)
+            );
+            statsList.add(stats);
+            total.add(stats);
+            if (earliestLastModifiedAge > stats.getEarliestLastModifiedAge()) {
+                earliestLastModifiedAge = stats.getEarliestLastModifiedAge();
+            }
+        }
+
+        assertThat(
+            total.estimatedNumberOfOperations(),
+            equalTo(statsList.stream().mapToInt(TranslogStats::estimatedNumberOfOperations).sum())
+        );
+        assertThat(total.getTranslogSizeInBytes(), equalTo(statsList.stream().mapToLong(TranslogStats::getTranslogSizeInBytes).sum()));
+        assertThat(total.getUncommittedOperations(), equalTo(statsList.stream().mapToInt(TranslogStats::getUncommittedOperations).sum()));
+        assertThat(
+            total.getUncommittedSizeInBytes(),
+            equalTo(statsList.stream().mapToLong(TranslogStats::getUncommittedSizeInBytes).sum())
+        );
+        assertThat(total.getEarliestLastModifiedAge(), equalTo(earliestLastModifiedAge));
+    }
+
+    public void testNegativeNumberOfOperations() {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(-1, 1, 1, 1, 1));
+        assertThat(e, hasToString(containsString("numberOfOperations must be >= 0")));
+        e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, -1, 1, 1));
+        assertThat(e, hasToString(containsString("uncommittedOperations must be >= 0")));
+    }
+
+    public void testNegativeSizeInBytes() {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, -1, 1, 1, 1));
+        assertThat(e, hasToString(containsString("translogSizeInBytes must be >= 0")));
+        e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, 1, -1, 1));
+        assertThat(e, hasToString(containsString("uncommittedSizeInBytes must be >= 0")));
+    }
+
+    public void testOldestEntryInSeconds() {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, 1, 1, -1));
+        assertThat(e, hasToString(containsString("earliestLastModifiedAge must be >= 0")));
+    }
+
+    public void testBasicSnapshot() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+        }
+
+        addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot(0, Long.MAX_VALUE)) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(1));
+        }
+
+        try (
+            Translog.Snapshot snapshot = translog.newSnapshot(0, randomIntBetween(0, 10));
+            Translog.Snapshot snapshot1 = translog.newSnapshot(0, randomIntBetween(0, 10))
+        ) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(1));
+
+            assertThat(snapshot1, SnapshotMatchers.size(1));
+            assertThat(snapshot1.totalOperations(), equalTo(1));
+        }
+    }
+
+    public void testReadLocation() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        ArrayList<Translog.Location> locs = new ArrayList<>();
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 1 })));
+        int i = 0;
+        for (Translog.Operation op : ops) {
+            assertEquals(op, translog.readOperation(locs.get(i++)));
+        }
+        assertNull(translog.readOperation(new Location(100, 0, 0)));
+    }
+
+    public void testSnapshotWithNewTranslog() throws IOException {
+        List<Closeable> toClose = new ArrayList<>();
+        try {
+            ArrayList<Translog.Operation> ops = new ArrayList<>();
+            Translog.Snapshot snapshot = translog.newSnapshot();
+            toClose.add(snapshot);
+            assertThat(snapshot, SnapshotMatchers.size(0));
+
+            addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+            Translog.Snapshot snapshot1 = translog.newSnapshot();
+            toClose.add(snapshot1);
+
+            addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 2 }));
+
+            assertThat(snapshot1, SnapshotMatchers.equalsTo(ops.get(0)));
+
+            translog.rollGeneration();
+            addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 3 }));
+
+            Translog.Snapshot snapshot2 = translog.newSnapshot();
+            toClose.add(snapshot2);
+            translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(2);
+            assertThat(snapshot2, containsOperationsInAnyOrder(ops));
+            assertThat(snapshot2.totalOperations(), equalTo(ops.size()));
+        } finally {
+            IOUtils.closeWhileHandlingException(toClose);
+        }
+    }
+
+    public void testSnapshotOnClosedTranslog() throws IOException {
+        assertTrue(Files.exists(translogDir.resolve(Translog.getFilename(1))));
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        translog.close();
+        AlreadyClosedException ex = expectThrows(AlreadyClosedException.class, () -> translog.newSnapshot());
+        assertEquals(ex.getMessage(), "translog is already closed");
+    }
+
+    public void testRangeSnapshot() throws Exception {
+        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        final int generations = between(2, 20);
+        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
+        for (int gen = 0; gen < generations; gen++) {
+            Set<Long> seqNos = new HashSet<>();
+            int numOps = randomIntBetween(1, 100);
+            for (int i = 0; i < numOps; i++) {
+                final long seqNo = randomValueOtherThanMany(seqNos::contains, () -> randomLongBetween(0, 1000));
+                minSeqNo = SequenceNumbers.min(minSeqNo, seqNo);
+                maxSeqNo = SequenceNumbers.max(maxSeqNo, seqNo);
+                seqNos.add(seqNo);
+            }
+            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
+            for (long seqNo : seqNos) {
+                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
+                translog.add(op);
+                ops.add(op);
+            }
+            operationsByGen.put(translog.currentFileGeneration(), ops);
+            translog.rollGeneration();
+            if (rarely()) {
+                translog.rollGeneration(); // empty generation
+            }
+        }
+
+        if (minSeqNo > 0) {
+            long fromSeqNo = randomLongBetween(0, minSeqNo - 1);
+            long toSeqNo = randomLongBetween(fromSeqNo, minSeqNo - 1);
+            try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+                assertThat(snapshot.totalOperations(), equalTo(0));
+                assertNull(snapshot.next());
+            }
+        }
+
+        long fromSeqNo = randomLongBetween(maxSeqNo + 1, Long.MAX_VALUE);
+        long toSeqNo = randomLongBetween(fromSeqNo, Long.MAX_VALUE);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+            assertThat(snapshot.totalOperations(), equalTo(0));
+            assertNull(snapshot.next());
+        }
+
+        fromSeqNo = randomLongBetween(0, 2000);
+        toSeqNo = randomLongBetween(fromSeqNo, 2000);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+            Set<Long> seenSeqNos = new HashSet<>();
+            List<Translog.Operation> expectedOps = new ArrayList<>();
+            for (long gen = translog.currentFileGeneration(); gen > 0; gen--) {
+                for (Translog.Operation op : operationsByGen.getOrDefault(gen, Collections.emptyList())) {
+                    if (fromSeqNo <= op.seqNo() && op.seqNo() <= toSeqNo && seenSeqNos.add(op.seqNo())) {
+                        expectedOps.add(op);
+                    }
+                }
+            }
+            assertThat(TestTranslog.drainSnapshot(snapshot, false), equalTo(expectedOps));
+        }
+    }
+
+    private Long populateTranslogOps(boolean withMissingOps) throws IOException {
+        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        final int generations = between(2, 20);
+        long currentSeqNo = 0L;
+        List<Translog.Operation> firstGenOps = null;
+        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
+        for (int gen = 0; gen < generations; gen++) {
+            List<Long> seqNos = new ArrayList<>();
+            int numOps = randomIntBetween(4, 10);
+            for (int i = 0; i < numOps; i++, currentSeqNo++) {
+                minSeqNo = SequenceNumbers.min(minSeqNo, currentSeqNo);
+                maxSeqNo = SequenceNumbers.max(maxSeqNo, currentSeqNo);
+                seqNos.add(currentSeqNo);
+            }
+            Collections.shuffle(seqNos, new Random(100));
+            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
+            for (long seqNo : seqNos) {
+                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
+                boolean shouldAdd = !withMissingOps || seqNo % 4 != 0;
+                if (shouldAdd) {
+                    translog.add(op);
+                    ops.add(op);
+                }
+            }
+            operationsByGen.put(translog.currentFileGeneration(), ops);
+            if (firstGenOps == null) {
+                firstGenOps = ops;
+            }
+            translog.rollGeneration();
+            if (rarely()) {
+                translog.rollGeneration(); // empty generation
+            }
+        }
+        return currentSeqNo;
+    }
+
+    public void testFullRangeSnapshot() throws Exception {
+        // Successful snapshot
+        long nextSeqNo = populateTranslogOps(false);
+        long fromSeqNo = 0L;
+        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
+            int totOps = 0;
+            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
+                totOps++;
+            }
+            assertEquals(totOps, toSeqNo - fromSeqNo + 1);
+        }
+    }
+
+    public void testFullRangeSnapshotWithFailures() throws Exception {
+        long nextSeqNo = populateTranslogOps(true);
+        long fromSeqNo = 0L;
+        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
+            int totOps = 0;
+            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
+                totOps++;
+            }
+            fail("Should throw exception for missing operations");
+        } catch (MissingHistoryOperationsException e) {
+            assertTrue(e.getMessage().contains("Not all operations between from_seqno"));
+        }
+    }
+
+    public void assertFileIsPresent(Translog translog, long id) {
+        if (Files.exists(translog.location().resolve(Translog.getFilename(id)))) {
+            return;
+        }
+        fail(Translog.getFilename(id) + " is not present in any location: " + translog.location());
+    }
+
+    public void assertFileDeleted(Translog translog, long id) {
+        assertFalse("translog [" + id + "] still exists", Files.exists(translog.location().resolve(Translog.getFilename(id))));
+    }
+
+    private void assertFilePresences(Translog translog) {
+        for (long gen = translog.getMinFileGeneration(); gen < translog.currentFileGeneration(); gen++) {
+            assertFileIsPresent(translog, gen);
+        }
+        for (long gen = 1; gen < translog.getMinFileGeneration(); gen++) {
+            assertFileDeleted(translog, gen);
+        }
+
+    }
+
+    public void testConcurrentWritesWithVaryingSize() throws Throwable {
+        final int opsPerThread = randomIntBetween(10, 200);
+        int threadCount = 2 + randomInt(5);
+
+        logger.info("testing with [{}] threads, each doing [{}] ops", threadCount, opsPerThread);
+        final BlockingQueue<TestTranslog.LocationOperation> writtenOperations = new ArrayBlockingQueue<>(threadCount * opsPerThread);
+
+        Thread[] threads = new Thread[threadCount];
+        final Exception[] threadExceptions = new Exception[threadCount];
+        final AtomicLong seqNoGenerator = new AtomicLong();
+        final CountDownLatch downLatch = new CountDownLatch(1);
+        for (int i = 0; i < threadCount; i++) {
+            final int threadId = i;
+            threads[i] = new TranslogThread(
+                translog,
+                downLatch,
+                opsPerThread,
+                threadId,
+                writtenOperations,
+                seqNoGenerator,
+                threadExceptions
+            );
+            threads[i].setDaemon(true);
+            threads[i].start();
+        }
+
+        downLatch.countDown();
+
+        for (int i = 0; i < threadCount; i++) {
+            if (threadExceptions[i] != null) {
+                throw threadExceptions[i];
+            }
+            threads[i].join(60 * 1000);
+        }
+
+        List<TestTranslog.LocationOperation> collect = new ArrayList<>(writtenOperations);
+        Collections.sort(collect);
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            for (TestTranslog.LocationOperation locationOperation : collect) {
+                Translog.Operation op = snapshot.next();
+                assertNotNull(op);
+                Translog.Operation expectedOp = locationOperation.operation;
+                if (randomBoolean()) {
+                    assertEquals(expectedOp, translog.readOperation(locationOperation.location));
+                }
+                assertEquals(expectedOp.opType(), op.opType());
+                switch (op.opType()) {
+                    case INDEX:
+                        Translog.Index indexOp = (Translog.Index) op;
+                        Translog.Index expIndexOp = (Translog.Index) expectedOp;
+                        assertEquals(expIndexOp.id(), indexOp.id());
+                        assertEquals(expIndexOp.routing(), indexOp.routing());
+                        assertEquals(expIndexOp.source(), indexOp.source());
+                        assertEquals(expIndexOp.version(), indexOp.version());
+                        break;
+                    case DELETE:
+                        Translog.Delete delOp = (Translog.Delete) op;
+                        Translog.Delete expDelOp = (Translog.Delete) expectedOp;
+                        assertEquals(expDelOp.id(), delOp.id());
+                        assertEquals(expDelOp.version(), delOp.version());
+                        break;
+                    case NO_OP:
+                        final Translog.NoOp noOp = (Translog.NoOp) op;
+                        final Translog.NoOp expectedNoOp = (Translog.NoOp) expectedOp;
+                        assertThat(noOp.seqNo(), equalTo(expectedNoOp.seqNo()));
+                        assertThat(noOp.primaryTerm(), equalTo(expectedNoOp.primaryTerm()));
+                        assertThat(noOp.reason(), equalTo(expectedNoOp.reason()));
+                        break;
+                    default:
+                        throw new AssertionError("unsupported operation type [" + op.opType() + "]");
+                }
+            }
+            assertNull(snapshot.next());
+        }
+
+    }
+
+    public void testTranslogCorruption() throws Exception {
+        TranslogConfig config = translog.getConfig();
+        String uuid = translog.getTranslogUUID();
+        List<Translog.Location> locations = new ArrayList<>();
+
+        int translogOperations = randomIntBetween(10, 1000);
+        for (int op = 0; op < translogOperations; op++) {
+            String ascii = randomAlphaOfLengthBetween(1, 50);
+            locations.add(translog.add(new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"))));
+
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+        }
+        translog.close();
+
+        TestTranslog.corruptRandomTranslogFile(logger, random(), translogDir, 0);
+
+        assertThat(expectThrows(TranslogCorruptedException.class, () -> {
+            try (Translog translog = openTranslog(config, uuid); Translog.Snapshot snapshot = translog.newSnapshot()) {
+                for (int i = 0; i < locations.size(); i++) {
+                    snapshot.next();
+                }
+            }
+        }).getMessage(), containsString(translogDir.toString()));
+
+        expectIntactTranslog = false;
+    }
+
+    public void testTruncatedTranslogs() throws Exception {
+        List<Translog.Location> locations = new ArrayList<>();
+
+        int translogOperations = randomIntBetween(10, 100);
+        for (int op = 0; op < translogOperations; op++) {
+            String ascii = randomAlphaOfLengthBetween(1, 50);
+            locations.add(translog.add(new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"))));
+        }
+        translog.sync();
+
+        truncateTranslogs(translogDir);
+
+        AtomicInteger truncations = new AtomicInteger(0);
+        try (Translog.Snapshot snap = translog.newSnapshot()) {
+            for (int i = 0; i < locations.size(); i++) {
+                try {
+                    assertNotNull(snap.next());
+                } catch (TranslogCorruptedException e) {
+                    assertThat(e.getCause(), instanceOf(EOFException.class));
+                    truncations.incrementAndGet();
+                }
+            }
+        }
+        assertThat("at least one truncation was caused and caught", truncations.get(), greaterThanOrEqualTo(1));
+    }
+
+    /**
+     * Randomly truncate some bytes in the translog files
+     */
+    private void truncateTranslogs(Path directory) throws Exception {
+        Path[] files = FileSystemUtils.files(directory, "translog-*");
+        for (Path file : files) {
+            try (FileChannel f = FileChannel.open(file, StandardOpenOption.READ, StandardOpenOption.WRITE)) {
+                long prevSize = f.size();
+                long newSize = prevSize - randomIntBetween(1, (int) prevSize / 2);
+                logger.info("--> truncating {}, prev: {}, now: {}", file, prevSize, newSize);
+                f.truncate(newSize);
+            }
+        }
+    }
+
+    private Term newUid(ParsedDocument doc) {
+        return new Term("_id", Uid.encodeId(doc.id()));
+    }
+
+    private Term newUid(String id) {
+        return new Term("_id", Uid.encodeId(id));
+    }
+
+    public void testVerifyTranslogIsNotDeleted() throws IOException {
+        assertFileIsPresent(translog, 1);
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.size(1));
+            assertFileIsPresent(translog, 1);
+            assertThat(snapshot.totalOperations(), equalTo(1));
+        }
+        translog.close();
+        assertFileDeleted(translog, 1);
+        assertFileIsPresent(translog, 2);
+    }
+
+    /**
+     * Tests that concurrent readers and writes maintain view and snapshot semantics
+     */
+    public void testConcurrentWriteViewsAndSnapshot() throws Throwable {
+        final Thread[] writers = new Thread[randomIntBetween(1, 3)];
+        final Thread[] readers = new Thread[randomIntBetween(1, 3)];
+        final int flushEveryOps = randomIntBetween(5, 100);
+        final int maxOps = randomIntBetween(200, 1000);
+        final Object signalReaderSomeDataWasIndexed = new Object();
+        final AtomicLong idGenerator = new AtomicLong();
+        final CyclicBarrier barrier = new CyclicBarrier(writers.length + readers.length + 1);
+
+        // a map of all written ops and their returned location.
+        final Map<Translog.Operation, Translog.Location> writtenOps = ConcurrentCollections.newConcurrentMap();
+
+        // a signal for all threads to stop
+        final AtomicBoolean run = new AtomicBoolean(true);
+
+        final Object flushMutex = new Object();
+        final AtomicLong lastCommittedLocalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final LocalCheckpointTracker tracker = LocalCheckpointTrackerTests.createEmptyTracker();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        // any errors on threads
+        final List<Exception> errors = new CopyOnWriteArrayList<>();
+        logger.info("using [{}] readers. [{}] writers. flushing every ~[{}] ops.", readers.length, writers.length, flushEveryOps);
+        for (int i = 0; i < writers.length; i++) {
+            final String threadName = "writer_" + i;
+            final int threadId = i;
+            writers[i] = new Thread(new AbstractRunnable() {
+                @Override
+                public void doRun() throws BrokenBarrierException, InterruptedException, IOException {
+                    barrier.await();
+                    int counter = 0;
+                    while (run.get() && idGenerator.get() < maxOps) {
+                        long id = idGenerator.getAndIncrement();
+                        final Translog.Operation op;
+                        final Translog.Operation.Type type = Translog.Operation.Type.values()[((int) (id % Translog.Operation.Type
+                            .values().length))];
+                        switch (type) {
+                            case CREATE:
+                            case INDEX:
+                                op = new Translog.Index("" + id, id, primaryTerm.get(), new byte[] { (byte) id });
+                                break;
+                            case DELETE:
+                                op = new Translog.Delete(Long.toString(id), id, primaryTerm.get());
+                                break;
+                            case NO_OP:
+                                op = new Translog.NoOp(id, 1, Long.toString(id));
+                                break;
+                            default:
+                                throw new AssertionError("unsupported operation type [" + type + "]");
+                        }
+                        Translog.Location location = translog.add(op);
+                        tracker.markSeqNoAsProcessed(id);
+                        Translog.Location existing = writtenOps.put(op, location);
+                        if (existing != null) {
+                            fail("duplicate op [" + op + "], old entry at " + location);
+                        }
+                        if (id % writers.length == threadId) {
+                            translog.ensureSynced(location);
+                        }
+                        if (id % flushEveryOps == 0) {
+                            synchronized (flushMutex) {
+                                // we need not do this concurrently as we need to make sure that the generation
+                                // we're committing - is still present when we're committing
+                                long localCheckpoint = tracker.getProcessedCheckpoint();
+                                translog.rollGeneration();
+                                // expose the new checkpoint (simulating a commit), before we trim the translog
+                                lastCommittedLocalCheckpoint.set(localCheckpoint);
+                                deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+                                translog.trimUnreferencedReaders();
+                            }
+                        }
+                        if (id % 7 == 0) {
+                            synchronized (signalReaderSomeDataWasIndexed) {
+                                signalReaderSomeDataWasIndexed.notifyAll();
+                            }
+                        }
+                        counter++;
+                    }
+                    logger.info("--> [{}] done. wrote [{}] ops.", threadName, counter);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(() -> new ParameterizedMessage("--> writer [{}] had an error", threadName), e);
+                    errors.add(e);
+                }
+            }, threadName);
+            writers[i].start();
+        }
+
+        for (int i = 0; i < readers.length; i++) {
+            final String threadId = "reader_" + i;
+            readers[i] = new Thread(new AbstractRunnable() {
+                Closeable retentionLock = null;
+                long committedLocalCheckpointAtView;
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(() -> new ParameterizedMessage("--> reader [{}] had an error", threadId), e);
+                    errors.add(e);
+                    try {
+                        closeRetentionLock();
+                    } catch (IOException inner) {
+                        inner.addSuppressed(e);
+                        logger.error("unexpected error while closing view, after failure", inner);
+                    }
+                }
+
+                void closeRetentionLock() throws IOException {
+                    if (retentionLock != null) {
+                        retentionLock.close();
+                    }
+                }
+
+                void acquireRetentionLock() throws IOException {
+                    closeRetentionLock();
+                    retentionLock = translog.acquireRetentionLock();
+                    // captures the last committed checkpoint, while holding the view, simulating
+                    // recovery logic which captures a view and gets a lucene commit
+                    committedLocalCheckpointAtView = lastCommittedLocalCheckpoint.get();
+                    logger.info("--> [{}] min gen after acquiring lock [{}]", threadId, translog.getMinFileGeneration());
+                }
+
+                @Override
+                protected void doRun() throws Exception {
+                    barrier.await();
+                    int iter = 0;
+                    while (idGenerator.get() < maxOps) {
+                        if (iter++ % 10 == 0) {
+                            acquireRetentionLock();
+                        }
+
+                        // captures al views that are written since the view was created (with a small caveat see bellow)
+                        // these are what we expect the snapshot to return (and potentially some more).
+                        Set<Translog.Operation> expectedOps = new HashSet<>(writtenOps.keySet());
+                        expectedOps.removeIf(op -> op.seqNo() <= committedLocalCheckpointAtView);
+                        try (Translog.Snapshot snapshot = translog.newSnapshot(committedLocalCheckpointAtView + 1L, Long.MAX_VALUE)) {
+                            Translog.Operation op;
+                            while ((op = snapshot.next()) != null) {
+                                expectedOps.remove(op);
+                            }
+                        }
+                        if (expectedOps.isEmpty() == false) {
+                            StringBuilder missed = new StringBuilder("missed ").append(expectedOps.size())
+                                .append(" operations from [")
+                                .append(committedLocalCheckpointAtView + 1L)
+                                .append("]");
+                            boolean failed = false;
+                            for (Translog.Operation expectedOp : expectedOps) {
+                                final Translog.Location loc = writtenOps.get(expectedOp);
+                                failed = true;
+                                missed.append("\n --> [").append(expectedOp).append("] written at ").append(loc);
+                            }
+                            if (failed) {
+                                fail(missed.toString());
+                            }
+                        }
+                        // slow down things a bit and spread out testing..
+                        synchronized (signalReaderSomeDataWasIndexed) {
+                            if (idGenerator.get() < maxOps) {
+                                signalReaderSomeDataWasIndexed.wait();
+                            }
+                        }
+                    }
+                    closeRetentionLock();
+                    logger.info("--> [{}] done. tested [{}] snapshots", threadId, iter);
+                }
+            }, threadId);
+            readers[i].start();
+        }
+
+        barrier.await();
+        logger.debug("--> waiting for threads to stop");
+        for (Thread thread : writers) {
+            thread.join();
+        }
+        logger.debug("--> waiting for readers to stop");
+        // force stopping, if all writers crashed
+        synchronized (signalReaderSomeDataWasIndexed) {
+            idGenerator.set(Long.MAX_VALUE);
+            signalReaderSomeDataWasIndexed.notifyAll();
+        }
+        for (Thread thread : readers) {
+            thread.join();
+        }
+        if (errors.size() > 0) {
+            Throwable e = errors.get(0);
+            for (Throwable suppress : errors.subList(1, errors.size())) {
+                e.addSuppressed(suppress);
+            }
+            throw e;
+        }
+        logger.info("--> test done. total ops written [{}]", writtenOps.size());
+    }
+
+    public void testSyncUpTo() throws IOException {
+        int translogOperations = randomIntBetween(10, 100);
+        int count = 0;
+        for (int op = 0; op < translogOperations; op++) {
+            int seqNo = ++count;
+            final Translog.Location location = translog.add(
+                new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
+            );
+            if (randomBoolean()) {
+                assertTrue("at least one operation pending", translog.syncNeeded());
+                assertTrue("this operation has not been synced", translog.ensureSynced(location));
+                // we are the last location so everything should be synced
+                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
+                seqNo = ++count;
+                translog.add(
+                    new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
+                );
+                assertTrue("one pending operation", translog.syncNeeded());
+                assertFalse("this op has been synced before", translog.ensureSynced(location)); // not syncing now
+                assertTrue("we only synced a previous operation yet", translog.syncNeeded());
+            }
+            if (rarely()) {
+                translog.rollGeneration();
+                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(location)); // not syncing now
+                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
+            }
+
+            if (randomBoolean()) {
+                translog.sync();
+                assertFalse("translog has been synced already", translog.ensureSynced(location));
+            }
+        }
+    }
+
+    public void testSyncUpToStream() throws IOException {
+        int iters = randomIntBetween(5, 10);
+        for (int i = 0; i < iters; i++) {
+            int translogOperations = randomIntBetween(10, 100);
+            int count = 0;
+            ArrayList<Location> locations = new ArrayList<>();
+            for (int op = 0; op < translogOperations; op++) {
+                if (rarely()) {
+                    translog.rollGeneration();
+                }
+                final Translog.Location location = translog.add(
+                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
+                );
+                locations.add(location);
+            }
+            Collections.shuffle(locations, random());
+            if (randomBoolean()) {
+                assertTrue("at least one operation pending", translog.syncNeeded());
+                assertTrue("this operation has not been synced", translog.ensureSynced(locations.stream()));
+                // we are the last location so everything should be synced
+                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
+            } else if (rarely()) {
+                translog.rollGeneration();
+                // not syncing now
+                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(locations.stream()));
+                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
+            } else {
+                translog.sync();
+                assertFalse("translog has been synced already", translog.ensureSynced(locations.stream()));
+            }
+            for (Location location : locations) {
+                assertFalse("all of the locations should be synced: " + location, translog.ensureSynced(location));
+            }
+        }
+    }
+
+    public void testLocationComparison() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        int count = 0;
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(
+                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
+                )
+            );
+            if (rarely() && translogOperations > op + 1) {
+                translog.rollGeneration();
+            }
+        }
+        Collections.shuffle(locations, random());
+        Translog.Location max = locations.get(0);
+        for (Translog.Location location : locations) {
+            max = max(max, location);
+        }
+
+        assertEquals(max.generation, translog.currentFileGeneration());
+        try (Translog.Snapshot snap = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+            Translog.Operation next;
+            Translog.Operation maxOp = null;
+            while ((next = snap.next()) != null) {
+                maxOp = next;
+            }
+            assertNotNull(maxOp);
+            assertEquals(maxOp.getSource().source.utf8ToString(), Integer.toString(count));
+        }
+    }
+
+    public static Translog.Location max(Translog.Location a, Translog.Location b) {
+        if (a.compareTo(b) > 0) {
+            return a;
+        }
+        return b;
+    }
+
+    public void testBasicCheckpoint() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        int lastSynced = -1;
+        long lastSyncedGlobalCheckpoint = globalCheckpoint.get();
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
+            );
+            if (randomBoolean()) {
+                globalCheckpoint.set(globalCheckpoint.get() + randomIntBetween(1, 16));
+            }
+            if (frequently()) {
+                translog.sync();
+                lastSynced = op;
+                lastSyncedGlobalCheckpoint = globalCheckpoint.get();
+            }
+        }
+        assertEquals(translogOperations, translog.totalOperations());
+        translog.add(
+            new Translog.Index(
+                "" + translogOperations,
+                translogOperations,
+                primaryTerm.get(),
+                Integer.toString(translogOperations).getBytes(Charset.forName("UTF-8"))
+            )
+        );
+
+        final Checkpoint checkpoint = Checkpoint.read(translog.location().resolve(Translog.CHECKPOINT_FILE_NAME));
+        try (
+            TranslogReader reader = translog.openReader(
+                translog.location().resolve(Translog.getFilename(translog.currentFileGeneration())),
+                checkpoint
+            )
+        ) {
+            assertEquals(lastSynced + 1, reader.totalOperations());
+            TranslogSnapshot snapshot = reader.newSnapshot();
+
+            for (int op = 0; op < translogOperations; op++) {
+                if (op <= lastSynced) {
+                    final Translog.Operation read = snapshot.next();
+                    assertEquals(Integer.toString(op), read.getSource().source.utf8ToString());
+                } else {
+                    Translog.Operation next = snapshot.next();
+                    assertNull(next);
+                }
+            }
+            Translog.Operation next = snapshot.next();
+            assertNull(next);
+        }
+        assertEquals(translogOperations + 1, translog.totalOperations());
+        assertThat(checkpoint.globalCheckpoint, equalTo(lastSyncedGlobalCheckpoint));
+        translog.close();
+    }
+
+    public void testTranslogWriter() throws IOException {
+        final TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1);
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        persistedSeqNoConsumer.set(persistedSeqNos::add);
+        final int numOps = scaledRandomIntBetween(8, 250000);
+        final Set<Long> seenSeqNos = new HashSet<>();
+        boolean opsHaveValidSequenceNumbers = randomBoolean();
+        for (int i = 0; i < numOps; i++) {
+            byte[] bytes = new byte[4];
+            DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+            out.writeInt(i);
+            long seqNo;
+            do {
+                seqNo = opsHaveValidSequenceNumbers ? randomNonNegativeLong() : SequenceNumbers.UNASSIGNED_SEQ_NO;
+                opsHaveValidSequenceNumbers = opsHaveValidSequenceNumbers || !rarely();
+            } while (seenSeqNos.contains(seqNo));
+            if (seqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
+                seenSeqNos.add(seqNo);
+            }
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), seqNo);
+        }
+        assertThat(persistedSeqNos, empty());
+        writer.sync();
+        persistedSeqNos.remove(SequenceNumbers.UNASSIGNED_SEQ_NO);
+        assertEquals(seenSeqNos, persistedSeqNos);
+
+        final BaseTranslogReader reader = randomBoolean()
+            ? writer
+            : translog.openReader(writer.path(), Checkpoint.read(translog.location().resolve(Translog.CHECKPOINT_FILE_NAME)));
+        for (int i = 0; i < numOps; i++) {
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
+            buffer.flip();
+            final int value = buffer.getInt();
+            assertEquals(i, value);
+        }
+        final long minSeqNo = seenSeqNos.stream().min(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
+        final long maxSeqNo = seenSeqNos.stream().max(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
+        assertThat(reader.getCheckpoint().minSeqNo, equalTo(minSeqNo));
+        assertThat(reader.getCheckpoint().maxSeqNo, equalTo(maxSeqNo));
+
+        byte[] bytes = new byte[4];
+        DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+        out.writeInt(2048);
+        writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
+
+        if (reader instanceof TranslogReader) {
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            try {
+                reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * numOps);
+                fail("read past EOF?");
+            } catch (EOFException ex) {
+                // expected
+            }
+            ((TranslogReader) reader).close();
+        } else {
+            // live reader!
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            final long pos = reader.getFirstOperationOffset() + 4 * numOps;
+            reader.readBytes(buffer, pos);
+            buffer.flip();
+            final int value = buffer.getInt();
+            assertEquals(2048, value);
+        }
+        IOUtils.close(writer);
+    }
+
+    public void testTranslogWriterCanFlushInAddOrReadCall() throws IOException {
+        Path tempDir = createTempDir();
+        final TranslogConfig temp = getTranslogConfig(tempDir);
+        final TranslogConfig config = new TranslogConfig(
+            temp.getShardId(),
+            temp.getTranslogPath(),
+            temp.getIndexSettings(),
+            temp.getBigArrays(),
+            new ByteSizeValue(1, ByteSizeUnit.KB),
+            ""
+        );
+
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        final AtomicInteger writeCalls = new AtomicInteger();
+
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel delegate = FileChannel.open(file, openOption);
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+
+                final FileChannel channel;
+                if (isCkpFile) {
+                    channel = delegate;
+                } else {
+                    channel = new FilterFileChannel(delegate) {
+
+                        @Override
+                        public int write(ByteBuffer src) throws IOException {
+                            writeCalls.incrementAndGet();
+                            return super.write(src);
+                        }
+                    };
+                }
+                success = true;
+                return channel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(delegate);
+                }
+            }
+        };
+
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                new DefaultTranslogDeletionPolicy(-1, -1, 0),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                persistedSeqNos::add
+            ) {
+                @Override
+                ChannelFactory getChannelFactory() {
+                    return channelFactory;
+                }
+            }
+        ) {
+            TranslogWriter writer = translog.getCurrent();
+            int initialWriteCalls = writeCalls.get();
+            byte[] bytes = new byte[256];
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 3);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 4);
+            assertThat(persistedSeqNos, empty());
+            assertEquals(initialWriteCalls, writeCalls.get());
+
+            if (randomBoolean()) {
+                // Since the buffer is full, this will flush before performing the add.
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
+                assertThat(persistedSeqNos, empty());
+                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
+            } else {
+                // Will flush on read
+                writer.readBytes(ByteBuffer.allocate(256), 0);
+                assertThat(persistedSeqNos, empty());
+                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
+
+                // Add after we the read flushed the buffer
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
+            }
+
+            writer.sync();
+
+            // Sequence numbers are marked as persisted after sync
+            assertThat(persistedSeqNos, contains(1L, 2L, 3L, 4L, 5L));
+        }
+    }
+
+    public void testTranslogWriterFsyncedWithLocalTranslog() throws IOException {
+        Path tempDir = createTempDir();
+        final TranslogConfig temp = getTranslogConfig(tempDir);
+        final TranslogConfig config = new TranslogConfig(
+            temp.getShardId(),
+            temp.getTranslogPath(),
+            temp.getIndexSettings(),
+            temp.getBigArrays(),
+            new ByteSizeValue(1, ByteSizeUnit.KB),
+            ""
+        );
+
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        final AtomicInteger translogFsyncCalls = new AtomicInteger();
+        final AtomicInteger checkpointFsyncCalls = new AtomicInteger();
+
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel delegate = FileChannel.open(file, openOption);
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+
+                final FileChannel channel;
+                if (isCkpFile) {
+                    channel = new FilterFileChannel(delegate) {
+                        @Override
+                        public void force(boolean metaData) throws IOException {
+                            checkpointFsyncCalls.incrementAndGet();
+                        }
+                    };
+                } else {
+                    channel = new FilterFileChannel(delegate) {
+
+                        @Override
+                        public void force(boolean metaData) throws IOException {
+                            translogFsyncCalls.incrementAndGet();
+                        }
+                    };
+                }
+                success = true;
+                return channel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(delegate);
+                }
+            }
+        };
+
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                new DefaultTranslogDeletionPolicy(-1, -1, 0),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                persistedSeqNos::add
+            ) {
+                @Override
+                ChannelFactory getChannelFactory() {
+                    return channelFactory;
+                }
+            }
+        ) {
+            TranslogWriter writer = translog.getCurrent();
+            byte[] bytes = new byte[256];
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 3);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 4);
+            writer.sync();
+            assertEquals(4, checkpointFsyncCalls.get());
+            assertEquals(3, translogFsyncCalls.get());
+            // Sequence numbers are marked as persisted after sync
+            assertThat(persistedSeqNos, contains(1L, 2L, 3L, 4L));
+        }
+    }
+
+    public void testTranslogWriterDoesNotBlockAddsOnWrite() throws IOException, InterruptedException {
+        Path tempDir = createTempDir();
+        final TranslogConfig config = getTranslogConfig(tempDir);
+        final AtomicBoolean startBlocking = new AtomicBoolean(false);
+        final CountDownLatch writeStarted = new CountDownLatch(1);
+        final CountDownLatch blocker = new CountDownLatch(1);
+        final Set<Long> persistedSeqNos = new HashSet<>();
+
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel delegate = FileChannel.open(file, openOption);
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+
+                final FileChannel channel;
+                if (isCkpFile) {
+                    channel = delegate;
+                } else {
+                    channel = new FilterFileChannel(delegate) {
+
+                        @Override
+                        public int write(ByteBuffer src) throws IOException {
+                            if (startBlocking.get()) {
+                                if (writeStarted.getCount() > 0) {
+                                    writeStarted.countDown();
+                                }
+                                try {
+                                    blocker.await();
+                                } catch (InterruptedException e) {
+                                    // Ignore
+                                }
+                            }
+                            return super.write(src);
+                        }
+
+                        @Override
+                        public void force(boolean metaData) throws IOException {
+                            if (startBlocking.get()) {
+                                if (writeStarted.getCount() > 0) {
+                                    writeStarted.countDown();
+                                }
+                                try {
+                                    blocker.await();
+                                } catch (InterruptedException e) {
+                                    // Ignore
+                                }
+                            }
+                            super.force(metaData);
+                        }
+                    };
+                }
+                success = true;
+                return channel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(delegate);
+                }
+            }
+        };
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                new DefaultTranslogDeletionPolicy(-1, -1, 0),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                persistedSeqNos::add
+            ) {
+                @Override
+                ChannelFactory getChannelFactory() {
+                    return channelFactory;
+                }
+            }
+        ) {
+            TranslogWriter writer = translog.getCurrent();
+
+            byte[] bytes = new byte[4];
+            DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(new byte[4]));
+            out.writeInt(1);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
+            assertThat(persistedSeqNos, empty());
+            startBlocking.set(true);
+            Thread thread = new Thread(() -> {
+                try {
+                    writer.sync();
+                } catch (IOException e) {
+                    throw new AssertionError(e);
+                }
+            });
+            thread.start();
+            writeStarted.await();
+
+            // Add will not block even though we are currently writing/syncing
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
+
+            blocker.countDown();
+            // Sync against so that both operations are written
+            writer.sync();
+
+            assertThat(persistedSeqNos, contains(1L, 2L));
+            thread.join();
+        }
+    }
+
+    public void testCloseIntoReader() throws IOException {
+        try (TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1)) {
+            final int numOps = randomIntBetween(8, 128);
+            for (int i = 0; i < numOps; i++) {
+                final byte[] bytes = new byte[4];
+                final DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+                out.writeInt(i);
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
+            }
+            writer.sync();
+            final Checkpoint writerCheckpoint = writer.getCheckpoint();
+            TranslogReader reader = writer.closeIntoReader();
+            try {
+                if (randomBoolean()) {
+                    reader.close();
+                    reader = translog.openReader(reader.path(), writerCheckpoint);
+                }
+                for (int i = 0; i < numOps; i++) {
+                    final ByteBuffer buffer = ByteBuffer.allocate(4);
+                    reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
+                    buffer.flip();
+                    final int value = buffer.getInt();
+                    assertEquals(i, value);
+                }
+                final Checkpoint readerCheckpoint = reader.getCheckpoint();
+                assertThat(readerCheckpoint, equalTo(writerCheckpoint));
+            } finally {
+                IOUtils.close(reader);
+            }
+        }
+    }
+
+    public void testBasicRecovery() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        Translog.TranslogGeneration translogGeneration = null;
+        int minUncommittedOp = -1;
+        final boolean commitOften = randomBoolean();
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
+            );
+            final boolean commit = commitOften ? frequently() : rarely();
+            if (commit && op < translogOperations - 1) {
+                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(op);
+                minUncommittedOp = op + 1;
+                translogGeneration = translog.getGeneration();
+            }
+        }
+        translog.sync();
+        TranslogConfig config = translog.getConfig();
+
+        translog.close();
+        if (translogGeneration == null) {
+            translog = createTranslog(config);
+            assertEquals(0, translog.stats().estimatedNumberOfOperations());
+            assertEquals(2, translog.currentFileGeneration());
+            assertFalse(translog.syncNeeded());
+            try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+                assertNull(snapshot.next());
+            }
+        } else {
+            translog = new LocalTranslog(
+                config,
+                translogGeneration.translogUUID,
+                translog.getDeletionPolicy(),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            );
+            assertEquals(
+                "lastCommitted must be 1 less than current",
+                translogGeneration.translogFileGeneration + 1,
+                translog.currentFileGeneration()
+            );
+            assertFalse(translog.syncNeeded());
+            try (Translog.Snapshot snapshot = translog.newSnapshot(minUncommittedOp, Long.MAX_VALUE)) {
+                for (int i = minUncommittedOp; i < translogOperations; i++) {
+                    assertEquals(
+                        "expected operation" + i + " to be in the previous translog but wasn't",
+                        translog.currentFileGeneration() - 1,
+                        locations.get(i).generation
+                    );
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null", next);
+                    assertEquals(i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+        }
+    }
+
+    public void testRecoveryUncommitted() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        final int prepareOp = randomIntBetween(0, translogOperations - 1);
+        Translog.TranslogGeneration translogGeneration = null;
+        final boolean sync = randomBoolean();
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
+            );
+            if (op == prepareOp) {
+                translogGeneration = translog.getGeneration();
+                translog.rollGeneration();
+                assertEquals(
+                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
+                    2L,
+                    translogGeneration.translogFileGeneration
+                );
+                assertNotNull(translogGeneration.translogUUID);
+            }
+        }
+        if (sync) {
+            translog.sync();
+        }
+        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
+        // translog here as well.
+        TranslogConfig config = translog.getConfig();
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            assertNotNull(translogGeneration);
+            assertEquals(
+                "lastCommitted must be 2 less than current - we never finished the commit",
+                translogGeneration.translogFileGeneration + 2,
+                translog.currentFileGeneration()
+            );
+            assertFalse(translog.syncNeeded());
+            try (Translog.Snapshot snapshot = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+                int upTo = sync ? translogOperations : prepareOp;
+                for (int i = 0; i < upTo; i++) {
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
+                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+        }
+        if (randomBoolean()) { // recover twice
+            try (
+                Translog translog = new LocalTranslog(
+                    config,
+                    translogUUID,
+                    deletionPolicy,
+                    () -> SequenceNumbers.NO_OPS_PERFORMED,
+                    primaryTerm::get,
+                    seqNo -> {}
+                )
+            ) {
+                assertNotNull(translogGeneration);
+                assertEquals(
+                    "lastCommitted must be 3 less than current - we never finished the commit and run recovery twice",
+                    translogGeneration.translogFileGeneration + 3,
+                    translog.currentFileGeneration()
+                );
+                assertFalse(translog.syncNeeded());
+                try (Translog.Snapshot snapshot = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+                    int upTo = sync ? translogOperations : prepareOp;
+                    for (int i = 0; i < upTo; i++) {
+                        Translog.Operation next = snapshot.next();
+                        assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
+                        assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                    }
+                }
+            }
+        }
+    }
+
+    public void testRecoveryUncommittedFileExists() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        final int prepareOp = randomIntBetween(0, translogOperations - 1);
+        Translog.TranslogGeneration translogGeneration = null;
+        final boolean sync = randomBoolean();
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
+            );
+            if (op == prepareOp) {
+                translogGeneration = translog.getGeneration();
+                translog.rollGeneration();
+                assertEquals(
+                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
+                    2L,
+                    translogGeneration.translogFileGeneration
+                );
+                assertNotNull(translogGeneration.translogUUID);
+            }
+        }
+        if (sync) {
+            translog.sync();
+        }
+        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
+        // translog here as well.
+        TranslogConfig config = translog.getConfig();
+        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
+        Checkpoint read = Checkpoint.read(ckp);
+        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
+
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            assertNotNull(translogGeneration);
+            assertEquals(
+                "lastCommitted must be 2 less than current - we never finished the commit",
+                translogGeneration.translogFileGeneration + 2,
+                translog.currentFileGeneration()
+            );
+            assertFalse(translog.syncNeeded());
+            try (Translog.Snapshot snapshot = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+                int upTo = sync ? translogOperations : prepareOp;
+                for (int i = 0; i < upTo; i++) {
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
+                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+        }
+
+        if (randomBoolean()) { // recover twice
+            try (
+                Translog translog = new LocalTranslog(
+                    config,
+                    translogUUID,
+                    deletionPolicy,
+                    () -> SequenceNumbers.NO_OPS_PERFORMED,
+                    primaryTerm::get,
+                    seqNo -> {}
+                )
+            ) {
+                assertNotNull(translogGeneration);
+                assertEquals(
+                    "lastCommitted must be 3 less than current - we never finished the commit and run recovery twice",
+                    translogGeneration.translogFileGeneration + 3,
+                    translog.currentFileGeneration()
+                );
+                assertFalse(translog.syncNeeded());
+                try (Translog.Snapshot snapshot = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+                    int upTo = sync ? translogOperations : prepareOp;
+                    for (int i = 0; i < upTo; i++) {
+                        Translog.Operation next = snapshot.next();
+                        assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
+                        assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                    }
+                }
+            }
+        }
+    }
+
+    public void testRecoveryUncommittedCorruptedCheckpoint() throws IOException {
+        int translogOperations = 100;
+        final int prepareOp = 44;
+        Translog.TranslogGeneration translogGeneration = null;
+        final boolean sync = randomBoolean();
+        for (int op = 0; op < translogOperations; op++) {
+            translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(StandardCharsets.UTF_8)));
+            if (op == prepareOp) {
+                translogGeneration = translog.getGeneration();
+                translog.rollGeneration();
+                assertEquals(
+                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
+                    2L,
+                    translogGeneration.translogFileGeneration
+                );
+                assertNotNull(translogGeneration.translogUUID);
+            }
+        }
+        translog.sync();
+        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
+        // translog here as well.
+        TranslogConfig config = translog.getConfig();
+        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
+        Checkpoint read = Checkpoint.read(ckp);
+        Checkpoint corrupted = Checkpoint.emptyTranslogCheckpoint(0, 0, SequenceNumbers.NO_OPS_PERFORMED, 0);
+        Checkpoint.write(
+            FileChannel::open,
+            config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)),
+            corrupted,
+            StandardOpenOption.WRITE,
+            StandardOpenOption.CREATE_NEW
+        );
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        final TranslogCorruptedException translogCorruptedException = expectThrows(
+            TranslogCorruptedException.class,
+            () -> new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        );
+        assertThat(
+            translogCorruptedException.getMessage(),
+            endsWith(
+                "] is corrupted, checkpoint file translog-3.ckp already exists but has corrupted content: expected Checkpoint{offset=2750, "
+                    + "numOps=55, generation=3, minSeqNo=45, maxSeqNo=99, globalCheckpoint=-1, minTranslogGeneration=1, trimmedAboveSeqNo=-2} "
+                    + "but got Checkpoint{offset=0, numOps=0, generation=0, minSeqNo=-1, maxSeqNo=-1, globalCheckpoint=-1, "
+                    + "minTranslogGeneration=0, trimmedAboveSeqNo=-2}"
+            )
+        );
+        Checkpoint.write(
+            FileChannel::open,
+            config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)),
+            read,
+            StandardOpenOption.WRITE,
+            StandardOpenOption.TRUNCATE_EXISTING
+        );
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            assertNotNull(translogGeneration);
+            assertEquals(
+                "lastCommitted must be 2 less than current - we never finished the commit",
+                translogGeneration.translogFileGeneration + 2,
+                translog.currentFileGeneration()
+            );
+            assertFalse(translog.syncNeeded());
+            try (Translog.Snapshot snapshot = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+                int upTo = sync ? translogOperations : prepareOp;
+                for (int i = 0; i < upTo; i++) {
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
+                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+        }
+    }
+
+    public void testSnapshotFromStreamInput() throws IOException {
+        BytesStreamOutput out = new BytesStreamOutput();
+        List<Translog.Operation> ops = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        for (int op = 0; op < translogOperations; op++) {
+            Translog.Index test = new Translog.Index(
+                "" + op,
+                op,
+                primaryTerm.get(),
+                Integer.toString(op).getBytes(Charset.forName("UTF-8"))
+            );
+            ops.add(test);
+        }
+        Translog.writeOperations(out, ops);
+        final List<Translog.Operation> readOperations = Translog.readOperations(out.bytes().streamInput(), "testSnapshotFromStreamInput");
+        assertEquals(ops.size(), readOperations.size());
+        assertEquals(ops, readOperations);
+    }
+
+    public void testSnapshotCurrentHasUnexpectedOperationsForTrimmedOperations() throws Exception {
+        int extraDocs = randomIntBetween(10, 15);
+
+        // increment primaryTerm to avoid potential negative numbers
+        primaryTerm.addAndGet(extraDocs);
+        translog.rollGeneration();
+
+        for (int op = 0; op < extraDocs; op++) {
+            String ascii = randomAlphaOfLengthBetween(1, 50);
+            Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get() - op, ascii.getBytes("UTF-8"));
+            translog.add(operation);
+        }
+
+        AssertionError error = expectThrows(AssertionError.class, () -> translog.trimOperations(primaryTerm.get(), 0));
+        assertThat(
+            error.getMessage(),
+            is(
+                "current should not have any operations with seq#:primaryTerm "
+                    + "[1:"
+                    + (primaryTerm.get() - 1)
+                    + "] > 0:"
+                    + primaryTerm.get()
+            )
+        );
+
+        primaryTerm.incrementAndGet();
+        translog.rollGeneration();
+
+        // add a single operation to current with seq# > trimmed seq# but higher primary term
+        Translog.Index operation = new Translog.Index("" + 1, 1L, primaryTerm.get(), randomAlphaOfLengthBetween(1, 50).getBytes("UTF-8"));
+        translog.add(operation);
+
+        // it is possible to trim after generation rollover
+        translog.trimOperations(primaryTerm.get(), 0);
+    }
+
+    public void testSnapshotTrimmedOperations() throws Exception {
+        final InMemoryTranslog inMemoryTranslog = new InMemoryTranslog();
+        final List<Translog.Operation> allOperations = new ArrayList<>();
+
+        for (int attempt = 0, maxAttempts = randomIntBetween(3, 10); attempt < maxAttempts; attempt++) {
+            List<Long> ops = LongStream.range(0, allOperations.size() + randomIntBetween(10, 15)).boxed().collect(Collectors.toList());
+            Randomness.shuffle(ops);
+
+            AtomicReference<String> source = new AtomicReference<>();
+            for (final long op : ops) {
+                source.set(randomAlphaOfLengthBetween(1, 50));
+
+                // have to use exactly the same source for same seq# if primaryTerm is not changed
+                if (primaryTerm.get() == translog.getCurrent().getPrimaryTerm()) {
+                    // use the latest source of op with the same seq# - therefore no break
+                    allOperations.stream()
+                        .filter(allOp -> allOp instanceof Translog.Index && allOp.seqNo() == op)
+                        .map(allOp -> ((Translog.Index) allOp).source().utf8ToString())
+                        .reduce((a, b) -> b)
+                        .ifPresent(source::set);
+                }
+
+                // use ongoing primaryTerms - or the same as it was
+                Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get(), source.get().getBytes("UTF-8"));
+                translog.add(operation);
+                inMemoryTranslog.add(operation);
+                allOperations.add(operation);
+            }
+
+            if (randomBoolean()) {
+                primaryTerm.incrementAndGet();
+                translog.rollGeneration();
+            }
+
+            long maxTrimmedSeqNo = randomInt(allOperations.size());
+
+            translog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
+            inMemoryTranslog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
+            translog.sync();
+
+            Collection<Translog.Operation> effectiveOperations = inMemoryTranslog.operations();
+
+            try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+                assertThat(snapshot, containsOperationsInAnyOrder(effectiveOperations));
+                assertThat(snapshot.totalOperations(), is(allOperations.size()));
+                assertThat(snapshot.skippedOperations(), is(allOperations.size() - effectiveOperations.size()));
+            }
+        }
+    }
+
+    /**
+     * this class mimic behaviour of original {@link Translog}
+     */
+    static class InMemoryTranslog {
+        private final Map<Long, Translog.Operation> operations = new HashMap<>();
+
+        void add(Translog.Operation operation) {
+            final Translog.Operation old = operations.put(operation.seqNo(), operation);
+            assert old == null || old.primaryTerm() <= operation.primaryTerm();
+        }
+
+        void trimOperations(long belowTerm, long aboveSeqNo) {
+            for (final Iterator<Map.Entry<Long, Translog.Operation>> it = operations.entrySet().iterator(); it.hasNext();) {
+                final Map.Entry<Long, Translog.Operation> next = it.next();
+                Translog.Operation op = next.getValue();
+                boolean drop = op.primaryTerm() < belowTerm && op.seqNo() > aboveSeqNo;
+                if (drop) {
+                    it.remove();
+                }
+            }
+        }
+
+        Collection<Translog.Operation> operations() {
+            return operations.values();
+        }
+    }
+
+    public void testRandomExceptionsOnTrimOperations() throws Exception {
+        Path tempDir = createTempDir();
+        final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+        fail.failNever();
+        TranslogConfig config = getTranslogConfig(tempDir);
+        List<FileChannel> fileChannels = new ArrayList<>();
+        final Translog failableTLog = getFailableTranslog(
+            fail,
+            config,
+            randomBoolean(),
+            false,
+            null,
+            createTranslogDeletionPolicy(),
+            fileChannels
+        );
+
+        IOException expectedException = null;
+        int translogOperations = 0;
+        final int maxAttempts = 10;
+        for (int attempt = 0; attempt < maxAttempts; attempt++) {
+            int maxTrimmedSeqNo;
+            fail.failNever();
+            int extraTranslogOperations = randomIntBetween(10, 100);
+
+            List<Integer> ops = IntStream.range(translogOperations, translogOperations + extraTranslogOperations)
+                .boxed()
+                .collect(Collectors.toList());
+            Randomness.shuffle(ops);
+            for (int op : ops) {
+                String ascii = randomAlphaOfLengthBetween(1, 50);
+                Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"));
+
+                failableTLog.add(operation);
+            }
+
+            translogOperations += extraTranslogOperations;
+
+            // at least one roll + inc of primary term has to be there - otherwise trim would not take place at all
+            // last attempt we have to make roll as well - otherwise could skip trimming as it has been trimmed already
+            boolean rollover = attempt == 0 || attempt == maxAttempts - 1 || randomBoolean();
+            if (rollover) {
+                primaryTerm.incrementAndGet();
+                failableTLog.rollGeneration();
+            }
+
+            maxTrimmedSeqNo = rollover ? translogOperations - randomIntBetween(4, 8) : translogOperations + 1;
+
+            // if we are so happy to reach the max attempts - fail it always`
+            fail.failRate(attempt < maxAttempts - 1 ? 25 : 100);
+            try {
+                failableTLog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
+            } catch (IOException e) {
+                expectedException = e;
+                break;
+            }
+        }
+
+        assertThat(expectedException, is(not(nullValue())));
+        assertThat(failableTLog.getTragicException(), equalTo(expectedException));
+        assertThat(fileChannels, is(not(empty())));
+        assertThat("all file channels have to be closed", fileChannels.stream().filter(f -> f.isOpen()).findFirst().isPresent(), is(false));
+
+        assertThat(failableTLog.isOpen(), is(false));
+        final AlreadyClosedException alreadyClosedException = expectThrows(AlreadyClosedException.class, () -> failableTLog.newSnapshot());
+        assertThat(alreadyClosedException.getMessage(), is("translog is already closed"));
+
+        fail.failNever();
+
+        // check that despite of IO exception translog is not corrupted
+        try (Translog reopenedTranslog = openTranslog(config, failableTLog.getTranslogUUID())) {
+            try (Translog.Snapshot snapshot = reopenedTranslog.newSnapshot()) {
+                assertThat(snapshot.totalOperations(), greaterThan(0));
+                Translog.Operation operation;
+                for (int i = 0; (operation = snapshot.next()) != null; i++) {
+                    assertNotNull("operation " + i + " must be non-null", operation);
+                }
+            }
+        }
+    }
+
+    public void testLocationHashCodeEquals() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        List<Translog.Location> locations2 = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        try (Translog translog2 = create(createTempDir())) {
+            for (int op = 0; op < translogOperations; op++) {
+                locations.add(
+                    translog.add(
+                        new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+                    )
+                );
+                locations2.add(
+                    translog2.add(
+                        new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+                    )
+                );
+            }
+            int iters = randomIntBetween(10, 100);
+            for (int i = 0; i < iters; i++) {
+                Translog.Location location = RandomPicks.randomFrom(random(), locations);
+                for (Translog.Location loc : locations) {
+                    if (loc == location) {
+                        assertTrue(loc.equals(location));
+                        assertEquals(loc.hashCode(), location.hashCode());
+                    } else {
+                        assertFalse(loc.equals(location));
+                    }
+                }
+                for (int j = 0; j < translogOperations; j++) {
+                    assertTrue(locations.get(j).equals(locations2.get(j)));
+                    assertEquals(locations.get(j).hashCode(), locations2.get(j).hashCode());
+                }
+            }
+        }
+    }
+
+    public void testOpenForeignTranslog() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(1, 10);
+        int firstUncommitted = 0;
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
+            );
+            if (randomBoolean()) {
+                translog.rollGeneration();
+                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(op);
+                translog.trimUnreferencedReaders();
+                firstUncommitted = op + 1;
+            }
+        }
+        final TranslogConfig config = translog.getConfig();
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        Translog.TranslogGeneration translogGeneration = translog.getGeneration();
+        translog.close();
+
+        final String foreignTranslog = randomRealisticUnicodeOfCodepointLengthBetween(1, translogGeneration.translogUUID.length());
+        try {
+            new LocalTranslog(
+                config,
+                foreignTranslog,
+                createTranslogDeletionPolicy(),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            );
+            fail("translog doesn't belong to this UUID");
+        } catch (TranslogCorruptedException ex) {
+
+        }
+        this.translog = new LocalTranslog(
+            config,
+            translogUUID,
+            deletionPolicy,
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        );
+        try (Translog.Snapshot snapshot = this.translog.newSnapshot(randomLongBetween(0, firstUncommitted), Long.MAX_VALUE)) {
+            for (int i = firstUncommitted; i < translogOperations; i++) {
+                Translog.Operation next = snapshot.next();
+                assertNotNull("" + i, next);
+                assertEquals(Integer.parseInt(next.getSource().source.utf8ToString()), i);
+            }
+            assertNull(snapshot.next());
+        }
+    }
+
+    public void testFailOnClosedWrite() throws IOException {
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
+        translog.close();
+        try {
+            translog.add(new Translog.Index("1", 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
+            fail("closed");
+        } catch (AlreadyClosedException ex) {
+            // all is well
+        }
+    }
+
+    public void testCloseConcurrently() throws Throwable {
+        final int opsPerThread = randomIntBetween(10, 200);
+        int threadCount = 2 + randomInt(5);
+
+        logger.info("testing with [{}] threads, each doing [{}] ops", threadCount, opsPerThread);
+        final BlockingQueue<TestTranslog.LocationOperation> writtenOperations = new ArrayBlockingQueue<>(threadCount * opsPerThread);
+
+        Thread[] threads = new Thread[threadCount];
+        final Exception[] threadExceptions = new Exception[threadCount];
+        final CountDownLatch downLatch = new CountDownLatch(1);
+        final AtomicLong seqNoGenerator = new AtomicLong();
+        for (int i = 0; i < threadCount; i++) {
+            final int threadId = i;
+            threads[i] = new TranslogThread(
+                translog,
+                downLatch,
+                opsPerThread,
+                threadId,
+                writtenOperations,
+                seqNoGenerator,
+                threadExceptions
+            );
+            threads[i].setDaemon(true);
+            threads[i].start();
+        }
+
+        downLatch.countDown();
+        translog.close();
+
+        for (int i = 0; i < threadCount; i++) {
+            if (threadExceptions[i] != null) {
+                if ((threadExceptions[i] instanceof AlreadyClosedException) == false) {
+                    throw threadExceptions[i];
+                }
+            }
+            threads[i].join(60 * 1000);
+        }
+    }
+
+    class TranslogThread extends Thread {
+        private final CountDownLatch downLatch;
+        private final int opsPerThread;
+        private final int threadId;
+        private final Collection<TestTranslog.LocationOperation> writtenOperations;
+        private final Exception[] threadExceptions;
+        private final Translog translog;
+        private final AtomicLong seqNoGenerator;
+
+        TranslogThread(
+            Translog translog,
+            CountDownLatch downLatch,
+            int opsPerThread,
+            int threadId,
+            Collection<TestTranslog.LocationOperation> writtenOperations,
+            AtomicLong seqNoGenerator,
+            Exception[] threadExceptions
+        ) {
+            this.translog = translog;
+            this.downLatch = downLatch;
+            this.opsPerThread = opsPerThread;
+            this.threadId = threadId;
+            this.writtenOperations = writtenOperations;
+            this.seqNoGenerator = seqNoGenerator;
+            this.threadExceptions = threadExceptions;
+        }
+
+        @Override
+        public void run() {
+            try {
+                downLatch.await();
+                for (int opCount = 0; opCount < opsPerThread; opCount++) {
+                    Translog.Operation op;
+                    final Translog.Operation.Type type = randomFrom(Translog.Operation.Type.values());
+                    switch (type) {
+                        case CREATE:
+                        case INDEX:
+                            op = new Translog.Index(
+                                threadId + "_" + opCount,
+                                seqNoGenerator.getAndIncrement(),
+                                primaryTerm.get(),
+                                randomUnicodeOfLengthBetween(1, 20 * 1024).getBytes("UTF-8")
+                            );
+                            break;
+                        case DELETE:
+                            op = new Translog.Delete(
+                                threadId + "_" + opCount,
+                                seqNoGenerator.getAndIncrement(),
+                                primaryTerm.get(),
+                                1 + randomInt(100000)
+                            );
+                            break;
+                        case NO_OP:
+                            op = new Translog.NoOp(seqNoGenerator.getAndIncrement(), primaryTerm.get(), randomAlphaOfLength(16));
+                            break;
+                        default:
+                            throw new AssertionError("unsupported operation type [" + type + "]");
+                    }
+
+                    Translog.Location loc = add(op);
+                    writtenOperations.add(new TestTranslog.LocationOperation(op, loc));
+                    if (rarely()) { // lets verify we can concurrently read this
+                        assertEquals(op, translog.readOperation(loc));
+                    }
+                    afterAdd();
+                }
+            } catch (Exception t) {
+                threadExceptions[threadId] = t;
+            }
+        }
+
+        protected Translog.Location add(Translog.Operation op) throws IOException {
+            return translog.add(op);
+        }
+
+        protected void afterAdd() throws IOException {}
+    }
+
+    public void testFailFlush() throws IOException {
+        Path tempDir = createTempDir();
+        final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+        TranslogConfig config = getTranslogConfig(tempDir);
+        Translog translog = getFailableTranslog(fail, config);
+
+        List<Translog.Location> locations = new ArrayList<>();
+        int opsSynced = 0;
+        boolean failed = false;
+        while (failed == false) {
+            try {
+                locations.add(
+                    translog.add(
+                        new Translog.Index(
+                            "" + opsSynced,
+                            opsSynced,
+                            primaryTerm.get(),
+                            Integer.toString(opsSynced).getBytes(Charset.forName("UTF-8"))
+                        )
+                    )
+                );
+                translog.sync();
+                opsSynced++;
+            } catch (MockDirectoryWrapper.FakeIOException ex) {
+                failed = true;
+                assertFalse(translog.isOpen());
+            } catch (IOException ex) {
+                failed = true;
+                assertFalse(translog.isOpen());
+                assertEquals("__FAKE__ no space left on device", ex.getMessage());
+            }
+            if (randomBoolean()) {
+                fail.failAlways();
+            } else {
+                fail.failNever();
+            }
+        }
+        fail.failNever();
+        if (randomBoolean()) {
+            try {
+                locations.add(
+                    translog.add(
+                        new Translog.Index(
+                            "" + opsSynced,
+                            opsSynced,
+                            primaryTerm.get(),
+                            Integer.toString(opsSynced).getBytes(Charset.forName("UTF-8"))
+                        )
+                    )
+                );
+                fail("we are already closed");
+            } catch (AlreadyClosedException ex) {
+                assertNotNull(ex.getCause());
+                if (ex.getCause() instanceof MockDirectoryWrapper.FakeIOException) {
+                    assertNull(ex.getCause().getMessage());
+                } else {
+                    assertEquals(ex.getCause().getMessage(), "__FAKE__ no space left on device");
+                }
+            }
+
+        }
+        Translog.TranslogGeneration translogGeneration = translog.getGeneration();
+        try {
+            translog.newSnapshot();
+            fail("already closed");
+        } catch (AlreadyClosedException ex) {
+            // all is well
+            assertNotNull(ex.getCause());
+            assertSame(translog.getTragicException(), ex.getCause());
+        }
+
+        try {
+            translog.rollGeneration();
+            fail("already closed");
+        } catch (AlreadyClosedException ex) {
+            assertNotNull(ex.getCause());
+            assertSame(translog.getTragicException(), ex.getCause());
+        }
+
+        assertFalse(translog.isOpen());
+        translog.close(); // we are closed
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        try (
+            Translog tlog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            assertEquals(
+                "lastCommitted must be 1 less than current",
+                translogGeneration.translogFileGeneration + 1,
+                tlog.currentFileGeneration()
+            );
+            assertFalse(tlog.syncNeeded());
+
+            try (Translog.Snapshot snapshot = tlog.newSnapshot()) {
+                assertEquals(opsSynced, snapshot.totalOperations());
+                for (int i = 0; i < opsSynced; i++) {
+                    assertEquals(
+                        "expected operation" + i + " to be in the previous translog but wasn't",
+                        tlog.currentFileGeneration() - 1,
+                        locations.get(i).generation
+                    );
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null", next);
+                    assertEquals(i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+        }
+    }
+
+    public void testTranslogOpsCountIsCorrect() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int numOps = randomIntBetween(100, 200);
+        LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer borders regularly
+        for (int opsAdded = 0; opsAdded < numOps; opsAdded++) {
+            locations.add(
+                translog.add(
+                    new Translog.Index(
+                        "" + opsAdded,
+                        opsAdded,
+                        primaryTerm.get(),
+                        lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8"))
+                    )
+                )
+            );
+            try (Translog.Snapshot snapshot = this.translog.newSnapshot()) {
+                assertEquals(opsAdded + 1, snapshot.totalOperations());
+                for (int i = 0; i < opsAdded; i++) {
+                    assertEquals(
+                        "expected operation" + i + " to be in the current translog but wasn't",
+                        translog.currentFileGeneration(),
+                        locations.get(i).generation
+                    );
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null", next);
+                }
+            }
+        }
+    }
+
+    public void testTragicEventCanBeAnyException() throws IOException {
+        Path tempDir = createTempDir();
+        final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+        TranslogConfig config = getTranslogConfig(tempDir);
+        Translog translog = getFailableTranslog(fail, config, false, true, null, createTranslogDeletionPolicy());
+        LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer boarders regularly
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8"))));
+        fail.failAlways();
+        try {
+            Translog.Location location = translog.add(
+                new Translog.Index("2", 1, primaryTerm.get(), lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8")))
+            );
+            if (randomBoolean()) {
+                translog.ensureSynced(location);
+            } else {
+                translog.sync();
+            }
+            // TODO once we have a mock FS that can simulate we can also fail on plain sync
+            fail("WTF");
+        } catch (UnknownException ex) {
+            // w00t
+        } catch (TranslogException ex) {
+            assertTrue(ex.getCause() instanceof UnknownException);
+        }
+        assertFalse(translog.isOpen());
+        assertTrue(translog.getTragicException() instanceof UnknownException);
+    }
+
+    public void testFatalIOExceptionsWhileWritingConcurrently() throws IOException, InterruptedException {
+        Path tempDir = createTempDir();
+        final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+
+        TranslogConfig config = getTranslogConfig(tempDir);
+        Translog translog = getFailableTranslog(fail, config);
+        final String translogUUID = translog.getTranslogUUID();
+
+        final int threadCount = randomIntBetween(1, 5);
+        Thread[] threads = new Thread[threadCount];
+        final Exception[] threadExceptions = new Exception[threadCount];
+        final CountDownLatch downLatch = new CountDownLatch(1);
+        final CountDownLatch added = new CountDownLatch(randomIntBetween(10, 100));
+        final AtomicLong seqNoGenerator = new AtomicLong();
+        List<TestTranslog.LocationOperation> writtenOperations = Collections.synchronizedList(new ArrayList<>());
+        for (int i = 0; i < threadCount; i++) {
+            final int threadId = i;
+            threads[i] = new TranslogThread(translog, downLatch, 200, threadId, writtenOperations, seqNoGenerator, threadExceptions) {
+                @Override
+                protected Translog.Location add(Translog.Operation op) throws IOException {
+                    Translog.Location add = super.add(op);
+                    added.countDown();
+                    return add;
+                }
+
+                @Override
+                protected void afterAdd() throws IOException {
+                    if (randomBoolean()) {
+                        translog.sync();
+                    }
+                }
+            };
+            threads[i].setDaemon(true);
+            threads[i].start();
+        }
+        downLatch.countDown();
+        added.await();
+        try (Closeable ignored = translog.acquireRetentionLock()) {
+            // this holds a reference to the current tlog channel such that it's not closed
+            // if we hit a tragic event. this is important to ensure that asserts inside the Translog#add doesn't trip
+            // otherwise our assertions here are off by one sometimes.
+            fail.failAlways();
+            for (int i = 0; i < threadCount; i++) {
+                threads[i].join();
+            }
+            boolean atLeastOneFailed = false;
+            for (Throwable ex : threadExceptions) {
+                if (ex != null) {
+                    assertTrue(ex.toString(), ex instanceof IOException || ex instanceof AlreadyClosedException);
+                    atLeastOneFailed = true;
+                }
+            }
+            if (atLeastOneFailed == false) {
+                try {
+                    boolean syncNeeded = translog.syncNeeded();
+                    translog.close();
+                    assertFalse("should have failed if sync was needed", syncNeeded);
+                } catch (IOException ex) {
+                    // boom now we failed
+                }
+            }
+            Collections.sort(writtenOperations, (a, b) -> a.location.compareTo(b.location));
+            assertFalse(translog.isOpen());
+            final Checkpoint checkpoint = Checkpoint.read(config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME));
+            // drop all that haven't been synced
+            writtenOperations.removeIf(next -> checkpoint.offset < (next.location.translogLocation + next.location.size));
+            try (
+                Translog tlog = new LocalTranslog(
+                    config,
+                    translogUUID,
+                    createTranslogDeletionPolicy(),
+                    () -> SequenceNumbers.NO_OPS_PERFORMED,
+                    primaryTerm::get,
+                    seqNo -> {}
+                );
+                Translog.Snapshot snapshot = tlog.newSnapshot()
+            ) {
+                if (writtenOperations.size() != snapshot.totalOperations()) {
+                    for (int i = 0; i < threadCount; i++) {
+                        if (threadExceptions[i] != null) {
+                            logger.info("Translog exception", threadExceptions[i]);
+                        }
+                    }
+                }
+                assertEquals(writtenOperations.size(), snapshot.totalOperations());
+                for (int i = 0; i < writtenOperations.size(); i++) {
+                    assertEquals(
+                        "expected operation" + i + " to be in the previous translog but wasn't",
+                        tlog.currentFileGeneration() - 1,
+                        writtenOperations.get(i).location.generation
+                    );
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null", next);
+                    assertEquals(next, writtenOperations.get(i).operation);
+                }
+            }
+        }
+    }
+
+    /**
+     * Tests the situation where the node crashes after a translog gen was committed to lucene, but before the translog had the chance
+     * to clean up its files.
+     */
+    public void testRecoveryFromAFutureGenerationCleansUp() throws IOException {
+        int translogOperations = randomIntBetween(10, 100);
+        int op = 0;
+        for (; op < translogOperations / 2; op++) {
+            translog.add(
+                new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+            );
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+        }
+        translog.rollGeneration();
+        long localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, op);
+        for (op = translogOperations / 2; op < translogOperations; op++) {
+            translog.add(
+                new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+            );
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+        }
+        long minRetainedGen = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
+        // engine blows up, after committing the above generation
+        translog.close();
+        TranslogConfig config = translog.getConfig();
+        final TranslogDeletionPolicy deletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
+        deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+        translog = new LocalTranslog(
+            config,
+            translog.getTranslogUUID(),
+            deletionPolicy,
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        );
+        assertThat(translog.getMinFileGeneration(), equalTo(1L));
+        // no trimming done yet, just recovered
+        for (long gen = 1; gen < translog.currentFileGeneration(); gen++) {
+            assertFileIsPresent(translog, gen);
+        }
+        translog.trimUnreferencedReaders();
+        for (long gen = 1; gen < minRetainedGen; gen++) {
+            assertFileDeleted(translog, gen);
+        }
+    }
+
+    /**
+     * Tests the situation where the node crashes after a translog gen was committed to lucene, but before the translog had the chance
+     * to clean up its files.
+     */
+    public void testRecoveryFromFailureOnTrimming() throws IOException {
+        Path tempDir = createTempDir();
+        final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+        fail.failNever();
+        final TranslogConfig config = getTranslogConfig(tempDir);
+        final long localCheckpoint;
+        final String translogUUID;
+        long minGenForRecovery = 1L;
+        try (Translog translog = getFailableTranslog(fail, config)) {
+            final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+            // disable retention so we trim things
+            deletionPolicy.setRetentionSizeInBytes(-1);
+            deletionPolicy.setRetentionAgeInMillis(-1);
+            translogUUID = translog.getTranslogUUID();
+            int translogOperations = randomIntBetween(10, 100);
+            int op = 0;
+            for (; op < translogOperations / 2; op++) {
+                translog.add(
+                    new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+                );
+                if (rarely()) {
+                    translog.rollGeneration();
+                }
+            }
+            translog.rollGeneration();
+            localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, op);
+            for (op = translogOperations / 2; op < translogOperations; op++) {
+                translog.add(
+                    new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
+                );
+                if (rarely()) {
+                    translog.rollGeneration();
+                }
+            }
+            deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+            minGenForRecovery = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
+            fail.failRandomly();
+            try {
+                translog.trimUnreferencedReaders();
+            } catch (Exception e) {
+                // expected...
+            }
+        }
+        final TranslogDeletionPolicy deletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
+        deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            // we don't know when things broke exactly
+            assertThat(translog.getMinFileGeneration(), greaterThanOrEqualTo(1L));
+            assertThat(translog.getMinFileGeneration(), lessThanOrEqualTo(minGenForRecovery));
+            assertFilePresences(translog);
+            minGenForRecovery = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
+            translog.trimUnreferencedReaders();
+            assertThat(translog.getMinFileGeneration(), equalTo(minGenForRecovery));
+            assertFilePresences(translog);
+        }
+    }
+
+    private Translog getFailableTranslog(TestTranslog.FailSwitch fail, final TranslogConfig config) throws IOException {
+        return getFailableTranslog(fail, config, randomBoolean(), false, null, createTranslogDeletionPolicy());
+    }
+
+    private Translog getFailableTranslog(
+        final TestTranslog.FailSwitch fail,
+        final TranslogConfig config,
+        final boolean partialWrites,
+        final boolean throwUnknownException,
+        String translogUUID,
+        final TranslogDeletionPolicy deletionPolicy
+    ) throws IOException {
+        return getFailableTranslog(fail, config, partialWrites, throwUnknownException, translogUUID, deletionPolicy, null);
+    }
+
+    private Translog getFailableTranslog(
+        final TestTranslog.FailSwitch fail,
+        final TranslogConfig config,
+        final boolean partialWrites,
+        final boolean throwUnknownException,
+        String translogUUID,
+        final TranslogDeletionPolicy deletionPolicy,
+        final List<FileChannel> fileChannels
+    ) throws IOException {
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel channel = FileChannel.open(file, openOption);
+            if (fileChannels != null) {
+                fileChannels.add(channel);
+            }
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+                ThrowingFileChannel throwingFileChannel = new ThrowingFileChannel(
+                    fail,
+                    isCkpFile ? false : partialWrites,
+                    throwUnknownException,
+                    channel
+                );
+                success = true;
+                return throwingFileChannel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(channel);
+                }
+            }
+        };
+        if (translogUUID == null) {
+            translogUUID = Translog.createEmptyTranslog(
+                config.getTranslogPath(),
+                SequenceNumbers.NO_OPS_PERFORMED,
+                shardId,
+                channelFactory,
+                primaryTerm.get()
+            );
+        }
+        return new LocalTranslog(
+            config,
+            translogUUID,
+            deletionPolicy,
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        ) {
+            @Override
+            ChannelFactory getChannelFactory() {
+                return channelFactory;
+            }
+
+            @Override
+            void deleteReaderFiles(TranslogReader reader) {
+                if (fail.fail()) {
+                    // simulate going OOM and dying just at the wrong moment.
+                    RuntimeException e = new RuntimeException("simulated");
+                    tragedy.setTragicException(e);
+                    throw e;
+                } else {
+                    super.deleteReaderFiles(reader);
+                }
+            }
+        };
+    }
+
+    public static class ThrowingFileChannel extends FilterFileChannel {
+        private final TestTranslog.FailSwitch fail;
+        private final boolean partialWrite;
+        private final boolean throwUnknownException;
+
+        public ThrowingFileChannel(TestTranslog.FailSwitch fail, boolean partialWrite, boolean throwUnknownException, FileChannel delegate)
+            throws MockDirectoryWrapper.FakeIOException {
+            super(delegate);
+            this.fail = fail;
+            this.partialWrite = partialWrite;
+            this.throwUnknownException = throwUnknownException;
+            if (fail.fail()) {
+                throw new MockDirectoryWrapper.FakeIOException();
+            }
+        }
+
+        @Override
+        public int read(ByteBuffer dst) throws IOException {
+            if (fail.fail()) {
+                throw new MockDirectoryWrapper.FakeIOException();
+            }
+            return super.read(dst);
+        }
+
+        @Override
+        public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
+            if (fail.fail()) {
+                throw new MockDirectoryWrapper.FakeIOException();
+            }
+            return super.read(dsts, offset, length);
+        }
+
+        @Override
+        public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public int write(ByteBuffer src, long position) throws IOException {
+            if (fail.fail()) {
+                if (partialWrite) {
+                    if (src.hasRemaining()) {
+                        final int pos = src.position();
+                        final int limit = src.limit();
+                        src.limit(randomIntBetween(pos, limit));
+                        super.write(src, position);
+                        src.limit(limit);
+                        src.position(pos);
+                        throw new IOException("__FAKE__ no space left on device");
+                    }
+                }
+                if (throwUnknownException) {
+                    throw new UnknownException();
+                } else {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+            }
+            return super.write(src, position);
+        }
+
+        @Override
+        public int write(ByteBuffer src) throws IOException {
+            if (fail.fail()) {
+                if (partialWrite) {
+                    if (src.hasRemaining()) {
+                        final int pos = src.position();
+                        final int limit = src.limit();
+                        src.limit(randomIntBetween(pos, limit));
+                        super.write(src);
+                        src.limit(limit);
+                        src.position(pos);
+                        throw new IOException("__FAKE__ no space left on device");
+                    }
+                }
+                if (throwUnknownException) {
+                    throw new UnknownException();
+                } else {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+            }
+            return super.write(src);
+        }
+
+        @Override
+        public void force(boolean metadata) throws IOException {
+            if (fail.fail()) {
+                if (throwUnknownException) {
+                    throw new UnknownException();
+                } else {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+            }
+            super.force(metadata);
+        }
+
+        @Override
+        public long position() throws IOException {
+            if (fail.fail()) {
+                if (throwUnknownException) {
+                    throw new UnknownException();
+                } else {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+            }
+            return super.position();
+        }
+    }
+
+    private static final class UnknownException extends RuntimeException {
+
+    }
+
+    // see https://github.com/elastic/elasticsearch/issues/15754
+    public void testFailWhileCreateWriteWithRecoveredTLogs() throws IOException {
+        Path tempDir = createTempDir();
+        TranslogConfig config = getTranslogConfig(tempDir);
+        Translog translog = createTranslog(config);
+        translog.add(new Translog.Index("boom", 0, primaryTerm.get(), "boom".getBytes(Charset.forName("UTF-8"))));
+        translog.close();
+        try {
+            new LocalTranslog(
+                config,
+                translog.getTranslogUUID(),
+                createTranslogDeletionPolicy(),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            ) {
+                @Override
+                protected TranslogWriter createWriter(
+                    long fileGeneration,
+                    long initialMinTranslogGen,
+                    long initialGlobalCheckpoint,
+                    LongConsumer persistedSequenceNumberConsumer
+                ) throws IOException {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+            };
+            // if we have a LeakFS here we fail if not all resources are closed
+            fail("should have been failed");
+        } catch (MockDirectoryWrapper.FakeIOException ex) {
+            // all is well
+        }
+    }
+
+    public void testRecoverWithUnbackedNextGen() throws IOException {
+        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
+        translog.close();
+        TranslogConfig config = translog.getConfig();
+
+        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
+        Checkpoint read = Checkpoint.read(ckp);
+        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
+        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
+        try (Translog tlog = openTranslog(config, translog.getTranslogUUID()); Translog.Snapshot snapshot = tlog.newSnapshot()) {
+            assertFalse(tlog.syncNeeded());
+
+            Translog.Operation op = snapshot.next();
+            assertNotNull("operation 1 must be non-null", op);
+            assertEquals("payload mismatch for operation 1", 1, Integer.parseInt(op.getSource().source.utf8ToString()));
+
+            tlog.add(new Translog.Index("" + 1, 1, primaryTerm.get(), Integer.toString(2).getBytes(Charset.forName("UTF-8"))));
+        }
+
+        try (Translog tlog = openTranslog(config, translog.getTranslogUUID()); Translog.Snapshot snapshot = tlog.newSnapshot()) {
+            assertFalse(tlog.syncNeeded());
+
+            Translog.Operation secondOp = snapshot.next();
+            assertNotNull("operation 2 must be non-null", secondOp);
+            assertEquals("payload mismatch for operation 2", Integer.parseInt(secondOp.getSource().source.utf8ToString()), 2);
+
+            Translog.Operation firstOp = snapshot.next();
+            assertNotNull("operation 1 must be non-null", firstOp);
+            assertEquals("payload mismatch for operation 1", Integer.parseInt(firstOp.getSource().source.utf8ToString()), 1);
+        }
+    }
+
+    public void testRecoverWithUnbackedNextGenInIllegalState() throws IOException {
+        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(0).getBytes(Charset.forName("UTF-8"))));
+        translog.close();
+        TranslogConfig config = translog.getConfig();
+        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
+        Checkpoint read = Checkpoint.read(ckp);
+        // don't copy the new file
+        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
+
+        TranslogException ex = expectThrows(
+            TranslogException.class,
+            () -> new LocalTranslog(
+                config,
+                translog.getTranslogUUID(),
+                translog.getDeletionPolicy(),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        );
+        assertEquals(ex.getMessage(), "failed to create new translog file");
+        assertEquals(ex.getCause().getClass(), FileAlreadyExistsException.class);
+    }
+
+    public void testRecoverWithUnbackedNextGenAndFutureFile() throws IOException {
+        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(0).getBytes(Charset.forName("UTF-8"))));
+        translog.close();
+        TranslogConfig config = translog.getConfig();
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+
+        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
+        Checkpoint read = Checkpoint.read(ckp);
+        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
+        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
+        // we add N+1 and N+2 to ensure we only delete the N+1 file and never jump ahead and wipe without the right condition
+        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 2) + ".tlog"));
+        try (
+            Translog tlog = new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        ) {
+            assertFalse(tlog.syncNeeded());
+            try (Translog.Snapshot snapshot = tlog.newSnapshot()) {
+                for (int i = 0; i < 1; i++) {
+                    Translog.Operation next = snapshot.next();
+                    assertNotNull("operation " + i + " must be non-null", next);
+                    assertEquals("payload missmatch", i, Integer.parseInt(next.getSource().source.utf8ToString()));
+                }
+            }
+            tlog.add(new Translog.Index("" + 1, 1, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
+        }
+
+        TranslogException ex = expectThrows(
+            TranslogException.class,
+            () -> new LocalTranslog(
+                config,
+                translogUUID,
+                deletionPolicy,
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                seqNo -> {}
+            )
+        );
+        assertEquals(ex.getMessage(), "failed to create new translog file");
+        assertEquals(ex.getCause().getClass(), FileAlreadyExistsException.class);
+    }
+
+    /**
+     * This test adds operations to the translog which might randomly throw an IOException. The only thing this test verifies is
+     * that we can, after we hit an exception, open and recover the translog successfully and retrieve all successfully synced operations
+     * from the transaction log.
+     */
+    public void testWithRandomException() throws IOException {
+        final int runs = randomIntBetween(5, 10);
+        for (int run = 0; run < runs; run++) {
+            Path tempDir = createTempDir();
+            final TestTranslog.FailSwitch fail = new TestTranslog.FailSwitch();
+            fail.failRandomly();
+            TranslogConfig config = getTranslogConfig(tempDir);
+            final int numOps = randomIntBetween(100, 200);
+            long localCheckpointOfSafeCommit = SequenceNumbers.NO_OPS_PERFORMED;
+            List<String> syncedDocs = new ArrayList<>();
+            List<String> unsynced = new ArrayList<>();
+            if (randomBoolean()) {
+                fail.onceFailedFailAlways();
+            }
+            String generationUUID = null;
+            try {
+                boolean committing = false;
+                final Translog failableTLog = getFailableTranslog(
+                    fail,
+                    config,
+                    randomBoolean(),
+                    false,
+                    generationUUID,
+                    createTranslogDeletionPolicy()
+                );
+                try {
+                    LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer boarders regularly
+                    for (int opsAdded = 0; opsAdded < numOps; opsAdded++) {
+                        String doc = lineFileDocs.nextDoc().toString();
+                        failableTLog.add(
+                            new Translog.Index("" + opsAdded, opsAdded, primaryTerm.get(), doc.getBytes(Charset.forName("UTF-8")))
+                        );
+                        unsynced.add(doc);
+                        if (randomBoolean()) {
+                            failableTLog.sync();
+                            syncedDocs.addAll(unsynced);
+                            unsynced.clear();
+                        }
+                        if (randomFloat() < 0.1) {
+                            // we have to sync here first otherwise we don't know if the sync succeeded if the commit fails
+                            failableTLog.sync();
+                            syncedDocs.addAll(unsynced);
+                            unsynced.clear();
+                            failableTLog.rollGeneration();
+                            committing = true;
+                            failableTLog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(opsAdded);
+                            syncedDocs.clear();
+                            failableTLog.trimUnreferencedReaders();
+                            committing = false;
+                            syncedDocs.clear();
+                        }
+                    }
+                    // we survived all the randomness!!!
+                    // lets close the translog and if it succeeds we are all synced again. If we don't do this we will close
+                    // it in the finally block but miss to copy over unsynced docs to syncedDocs and fail the assertion down the road...
+                    failableTLog.close();
+                    syncedDocs.addAll(unsynced);
+                    unsynced.clear();
+                } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
+                    assertEquals(ex, failableTLog.getTragicException());
+                } catch (IOException ex) {
+                    assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
+                    assertEquals(ex, failableTLog.getTragicException());
+                } catch (RuntimeException ex) {
+                    assertEquals(ex.getMessage(), "simulated");
+                    assertEquals(ex, failableTLog.getTragicException());
+                } finally {
+                    Checkpoint checkpoint = Translog.readCheckpoint(config.getTranslogPath());
+                    if (checkpoint.numOps == unsynced.size() + syncedDocs.size()) {
+                        syncedDocs.addAll(unsynced); // failed in fsync but got fully written
+                        unsynced.clear();
+                    }
+                    if (committing && checkpoint.minTranslogGeneration == checkpoint.generation) {
+                        // we were committing and blew up in one of the syncs, but they made it through
+                        syncedDocs.clear();
+                        assertThat(unsynced, empty());
+                    }
+                    generationUUID = failableTLog.getTranslogUUID();
+                    localCheckpointOfSafeCommit = failableTLog.getDeletionPolicy().getLocalCheckpointOfSafeCommit();
+                    IOUtils.closeWhileHandlingException(failableTLog);
+                }
+            } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
+                // failed - that's ok, we didn't even create it
+            } catch (IOException ex) {
+                assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
+            }
+            // now randomly open this failing tlog again just to make sure we can also recover from failing during recovery
+            if (randomBoolean()) {
+                try {
+                    TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy();
+                    deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpointOfSafeCommit);
+                    IOUtils.close(getFailableTranslog(fail, config, randomBoolean(), false, generationUUID, deletionPolicy));
+                } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
+                    // failed - that's ok, we didn't even create it
+                } catch (IOException ex) {
+                    assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
+                }
+            }
+
+            fail.failNever(); // we don't wanna fail here but we might since we write a new checkpoint and create a new tlog file
+            TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy();
+            deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpointOfSafeCommit);
+            if (generationUUID == null) {
+                // we never managed to successfully create a translog, make it
+                generationUUID = Translog.createEmptyTranslog(
+                    config.getTranslogPath(),
+                    SequenceNumbers.NO_OPS_PERFORMED,
+                    shardId,
+                    primaryTerm.get()
+                );
+            }
+            try (
+                Translog translog = new LocalTranslog(
+                    config,
+                    generationUUID,
+                    deletionPolicy,
+                    () -> SequenceNumbers.NO_OPS_PERFORMED,
+                    primaryTerm::get,
+                    seqNo -> {}
+                );
+                Translog.Snapshot snapshot = translog.newSnapshot(localCheckpointOfSafeCommit + 1, Long.MAX_VALUE)
+            ) {
+                assertEquals(syncedDocs.size(), snapshot.totalOperations());
+                for (int i = 0; i < syncedDocs.size(); i++) {
+                    Translog.Operation next = snapshot.next();
+                    assertEquals(syncedDocs.get(i), next.getSource().source.utf8ToString());
+                    assertNotNull("operation " + i + " must be non-null", next);
+                }
+            }
+        }
+    }
+
+    private Checkpoint randomCheckpoint() {
+        final long a = randomNonNegativeLong();
+        final long b = randomNonNegativeLong();
+        final long minSeqNo;
+        final long maxSeqNo;
+        if (a <= b) {
+            minSeqNo = a;
+            maxSeqNo = b;
+        } else {
+            minSeqNo = b;
+            maxSeqNo = a;
+        }
+        final long generation = randomNonNegativeLong();
+        return new Checkpoint(
+            randomLong(),
+            randomInt(),
+            generation,
+            minSeqNo,
+            maxSeqNo,
+            randomNonNegativeLong(),
+            randomLongBetween(1, generation),
+            maxSeqNo
+        );
+    }
+
+    public void testCheckpointOnDiskFull() throws IOException {
+        final Checkpoint checkpoint = randomCheckpoint();
+        Path tempDir = createTempDir();
+        Checkpoint.write(
+            FileChannel::open,
+            tempDir.resolve("foo.cpk"),
+            checkpoint,
+            StandardOpenOption.WRITE,
+            StandardOpenOption.CREATE_NEW
+        );
+        final Checkpoint checkpoint2 = randomCheckpoint();
+        try {
+            Checkpoint.write((p, o) -> {
+                if (randomBoolean()) {
+                    throw new MockDirectoryWrapper.FakeIOException();
+                }
+                FileChannel open = FileChannel.open(p, o);
+                TestTranslog.FailSwitch failSwitch = new TestTranslog.FailSwitch();
+                failSwitch.failNever(); // don't fail in the ctor
+                ThrowingFileChannel channel = new ThrowingFileChannel(failSwitch, false, false, open);
+                failSwitch.failAlways();
+                return channel;
+
+            }, tempDir.resolve("foo.cpk"), checkpoint2, StandardOpenOption.WRITE);
+            fail("should have failed earlier");
+        } catch (MockDirectoryWrapper.FakeIOException ex) {
+            // fine
+        }
+        Checkpoint read = Checkpoint.read(tempDir.resolve("foo.cpk"));
+        assertEquals(read, checkpoint);
+    }
+
+    public void testLegacyCheckpointVersion() throws IOException {
+        expectThrows(
+            TranslogCorruptedException.class,
+            IndexFormatTooOldException.class,
+            () -> Checkpoint.read(getDataPath("/org/opensearch/index/checkpoint/v2.ckp.binary"))
+        );
+    }
+
+    /**
+     * Tests that closing views after the translog is fine and we can reopen the translog
+     */
+    public void testPendingDelete() throws IOException {
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        translog.rollGeneration();
+        TranslogConfig config = translog.getConfig();
+        final String translogUUID = translog.getTranslogUUID();
+        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(config.getIndexSettings());
+        translog.close();
+        translog = new LocalTranslog(
+            config,
+            translogUUID,
+            deletionPolicy,
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        );
+        translog.add(new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 2 }));
+        translog.rollGeneration();
+        Closeable lock = translog.acquireRetentionLock();
+        translog.add(new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 3 }));
+        translog.close();
+        IOUtils.close(lock);
+        translog = new LocalTranslog(
+            config,
+            translogUUID,
+            deletionPolicy,
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        );
+    }
+
+    public static Translog.Location randomTranslogLocation() {
+        return new Translog.Location(randomLong(), randomLong(), randomInt());
+    }
+
+    public void testTranslogOpSerialization() throws Exception {
+        BytesReference B_1 = new BytesArray(new byte[] { 1 });
+        SeqNoFieldMapper.SequenceIDFields seqID = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
+        long randomSeqNum = randomNonNegativeLong();
+        long randomPrimaryTerm = randomBoolean() ? 0 : randomNonNegativeLong();
+        seqID.seqNo.setLongValue(randomSeqNum);
+        seqID.seqNoDocValue.setLongValue(randomSeqNum);
+        seqID.primaryTerm.setLongValue(randomPrimaryTerm);
+        Field idField = new Field("_id", Uid.encodeId("1"), IdFieldMapper.Defaults.FIELD_TYPE);
+        Field versionField = new NumericDocValuesField("_version", 1);
+        Document document = new Document();
+        document.add(new TextField("value", "test", Field.Store.YES));
+        document.add(idField);
+        document.add(versionField);
+        document.add(seqID.seqNo);
+        document.add(seqID.seqNoDocValue);
+        document.add(seqID.primaryTerm);
+        ParsedDocument doc = new ParsedDocument(versionField, seqID, "1", null, Arrays.asList(document), B_1, MediaTypeRegistry.JSON, null);
+
+        Engine.Index eIndex = new Engine.Index(
+            newUid(doc),
+            doc,
+            randomSeqNum,
+            randomPrimaryTerm,
+            1,
+            VersionType.INTERNAL,
+            Origin.PRIMARY,
+            0,
+            0,
+            false,
+            SequenceNumbers.UNASSIGNED_SEQ_NO,
+            0
+        );
+        Engine.IndexResult eIndexResult = new Engine.IndexResult(1, randomPrimaryTerm, randomSeqNum, true);
+        Translog.Index index = new Translog.Index(eIndex, eIndexResult);
+
+        Version wireVersion = VersionUtils.randomVersionBetween(random(), Version.CURRENT.minimumCompatibilityVersion(), Version.CURRENT);
+        BytesStreamOutput out = new BytesStreamOutput();
+        out.setVersion(wireVersion);
+        Translog.Operation.writeOperation(out, index);
+        StreamInput in = out.bytes().streamInput();
+        in.setVersion(wireVersion);
+        Translog.Index serializedIndex = (Translog.Index) Translog.Operation.readOperation(in);
+        assertEquals(index, serializedIndex);
+
+        Engine.Delete eDelete = new Engine.Delete(
+            doc.id(),
+            newUid(doc),
+            randomSeqNum,
+            randomPrimaryTerm,
+            2,
+            VersionType.INTERNAL,
+            Origin.PRIMARY,
+            0,
+            SequenceNumbers.UNASSIGNED_SEQ_NO,
+            0
+        );
+        Engine.DeleteResult eDeleteResult = new Engine.DeleteResult(2, randomPrimaryTerm, randomSeqNum, true);
+        Translog.Delete delete = new Translog.Delete(eDelete, eDeleteResult);
+
+        out = new BytesStreamOutput();
+        out.setVersion(wireVersion);
+        Translog.Operation.writeOperation(out, delete);
+        in = out.bytes().streamInput();
+        in.setVersion(wireVersion);
+        Translog.Delete serializedDelete = (Translog.Delete) Translog.Operation.readOperation(in);
+        assertEquals(delete, serializedDelete);
+    }
+
+    public void testRollGeneration() throws Exception {
+        // make sure we keep some files around
+        final boolean longRetention = randomBoolean();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        if (longRetention) {
+            deletionPolicy.setRetentionAgeInMillis(3600 * 1000);
+        } else {
+            deletionPolicy.setRetentionAgeInMillis(-1);
+        }
+        // we control retention via time, disable size based calculations for simplicity
+        deletionPolicy.setRetentionSizeInBytes(-1);
+        final long generation = translog.currentFileGeneration();
+        final int rolls = randomIntBetween(1, 16);
+        int totalOperations = 0;
+        int seqNo = 0;
+        final List<Long> primaryTerms = new ArrayList<>();
+        primaryTerms.add(primaryTerm.get()); // We always create an empty translog.
+        primaryTerms.add(primaryTerm.get());
+        for (int i = 0; i < rolls; i++) {
+            final int operations = randomIntBetween(1, 128);
+            for (int j = 0; j < operations; j++) {
+                translog.add(new Translog.NoOp(seqNo++, primaryTerm.get(), "test"));
+                totalOperations++;
+            }
+            try (ReleasableLock ignored = translog.writeLock.acquire()) {
+                if (randomBoolean()) {
+                    primaryTerm.incrementAndGet();
+                }
+                translog.rollGeneration();
+                primaryTerms.add(primaryTerm.get());
+            }
+            assertThat(translog.currentFileGeneration(), equalTo(generation + i + 1));
+            assertThat(translog.getCurrent().getPrimaryTerm(), equalTo(primaryTerm.get()));
+            assertThat(translog.totalOperations(), equalTo(totalOperations));
+        }
+        for (int i = 0; i <= rolls; i++) {
+            assertFileIsPresent(translog, generation + i);
+            final List<Long> storedPrimaryTerms = Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
+                .map(t -> t.getPrimaryTerm())
+                .collect(Collectors.toList());
+            assertThat(storedPrimaryTerms, equalTo(primaryTerms));
+        }
+
+        final BaseTranslogReader minRetainedReader = randomFrom(
+            Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
+                .filter(r -> r.getCheckpoint().minSeqNo >= 0)
+                .collect(Collectors.toList())
+        );
+        int retainedOps = Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
+            .filter(r -> r.getCheckpoint().generation >= minRetainedReader.generation)
+            .mapToInt(r -> r.getCheckpoint().numOps)
+            .sum();
+        deletionPolicy.setLocalCheckpointOfSafeCommit(
+            randomLongBetween(minRetainedReader.getCheckpoint().minSeqNo, minRetainedReader.getCheckpoint().maxSeqNo) - 1
+        );
+        translog.trimUnreferencedReaders();
+        assertThat(translog.currentFileGeneration(), equalTo(generation + rolls));
+        assertThat(translog.stats().getUncommittedOperations(), equalTo(retainedOps));
+        if (longRetention) {
+            for (int i = 0; i <= rolls; i++) {
+                assertFileIsPresent(translog, generation + i);
+            }
+            deletionPolicy.setRetentionAgeInMillis(randomBoolean() ? 100 : -1);
+            assertBusy(() -> {
+                translog.trimUnreferencedReaders();
+                for (long i = 0; i < minRetainedReader.generation; i++) {
+                    assertFileDeleted(translog, i);
+                }
+            });
+        } else {
+            // immediate cleanup
+            for (long i = 0; i < minRetainedReader.generation; i++) {
+                assertFileDeleted(translog, i);
+            }
+        }
+        for (long i = minRetainedReader.generation; i < generation + rolls; i++) {
+            assertFileIsPresent(translog, i);
+        }
+    }
+
+    public void testMinSeqNoBasedAPI() throws IOException {
+        final int operations = randomIntBetween(1, 512);
+        final List<Long> shuffledSeqNos = LongStream.range(0, operations).boxed().collect(Collectors.toList());
+        Randomness.shuffle(shuffledSeqNos);
+        final List<Tuple<Long, Long>> seqNos = new ArrayList<>();
+        final Map<Long, Long> terms = new HashMap<>();
+        for (final Long seqNo : shuffledSeqNos) {
+            seqNos.add(Tuple.tuple(seqNo, terms.computeIfAbsent(seqNo, k -> 0L)));
+            Long repeatingTermSeqNo = randomFrom(seqNos.stream().map(Tuple::v1).collect(Collectors.toList()));
+            seqNos.add(Tuple.tuple(repeatingTermSeqNo, terms.get(repeatingTermSeqNo)));
+        }
+
+        for (final Tuple<Long, Long> tuple : seqNos) {
+            translog.add(new Translog.NoOp(tuple.v1(), tuple.v2(), "test"));
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+        }
+
+        final Map<Long, Set<Tuple<Long, Long>>> seqNoPerGeneration = new HashMap<>();
+        final Map<Long, Integer> opCountPerGeneration = new HashMap<>();
+        // one extra roll to make sure that all ops so far are available via a reader and a translog-{gen}.ckp
+        // file in a consistent way, in order to simplify checking code.
+        translog.rollGeneration();
+        for (long seqNo = 0; seqNo < operations; seqNo++) {
+            final Set<Tuple<Long, Long>> seenSeqNos = new HashSet<>();
+            final long generation = translog.getMinGenerationForSeqNo(seqNo).translogFileGeneration;
+            int expectedSnapshotOps = 0;
+            for (long g = generation; g < translog.currentFileGeneration(); g++) {
+                if (!seqNoPerGeneration.containsKey(g)) {
+                    final Set<Tuple<Long, Long>> generationSeenSeqNos = new HashSet<>();
+                    int opCount = 0;
+                    final Checkpoint checkpoint = Checkpoint.read(translog.location().resolve(Translog.getCommitCheckpointFileName(g)));
+                    try (TranslogReader reader = translog.openReader(translog.location().resolve(Translog.getFilename(g)), checkpoint)) {
+                        TranslogSnapshot snapshot = reader.newSnapshot();
+                        Translog.Operation operation;
+                        while ((operation = snapshot.next()) != null) {
+                            generationSeenSeqNos.add(Tuple.tuple(operation.seqNo(), operation.primaryTerm()));
+                            opCount++;
+                        }
+                        assertThat(opCount, equalTo(reader.totalOperations()));
+                        assertThat(opCount, equalTo(checkpoint.numOps));
+                    }
+                    opCountPerGeneration.put(g, opCount);
+                    seqNoPerGeneration.put(g, generationSeenSeqNos);
+                }
+                final Set<Tuple<Long, Long>> generationSeqNo = seqNoPerGeneration.get(g);
+                if (generationSeqNo.stream().map(Tuple::v1).max(Long::compareTo).orElse(Long.MIN_VALUE) >= seqNo) {
+                    expectedSnapshotOps += opCountPerGeneration.get(g);
+                }
+                seenSeqNos.addAll(generationSeqNo);
+            }
+            assertThat(translog.estimateTotalOperationsFromMinSeq(seqNo), equalTo(expectedSnapshotOps));
+            int readFromSnapshot = 0;
+            try (Translog.Snapshot snapshot = translog.newSnapshot(seqNo, Long.MAX_VALUE)) {
+                assertThat(snapshot.totalOperations(), equalTo(expectedSnapshotOps));
+                Translog.Operation op;
+                while ((op = snapshot.next()) != null) {
+                    assertThat(Tuple.tuple(op.seqNo(), op.primaryTerm()), is(in(seenSeqNos)));
+                    readFromSnapshot++;
+                }
+                readFromSnapshot += snapshot.skippedOperations();
+            }
+            assertThat(readFromSnapshot, equalTo(expectedSnapshotOps));
+            final long seqNoLowerBound = seqNo;
+            final Set<Tuple<Long, Long>> expected = seqNos.stream().filter(t -> t.v1() >= seqNoLowerBound).collect(Collectors.toSet());
+            seenSeqNos.retainAll(expected);
+            assertThat(seenSeqNos, equalTo(expected));
+        }
+    }
+
+    public void testSimpleCommit() throws IOException {
+        final int operations = randomIntBetween(1, 4096);
+        long seqNo = 0;
+        for (int i = 0; i < operations; i++) {
+            translog.add(new Translog.NoOp(seqNo++, primaryTerm.get(), "test'"));
+            if (rarely()) {
+                if (rarely()) {
+                    primaryTerm.incrementAndGet();
+                }
+                translog.rollGeneration();
+            }
+        }
+        translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(randomLongBetween(0, operations));
+    }
+
+    public void testAcquiredLockIsPassedToDeletionPolicy() throws IOException {
+        final int operations = randomIntBetween(1, 4096);
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        for (int i = 0; i < operations; i++) {
+            translog.add(new Translog.NoOp(i, 0, "test"));
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+            if (rarely()) {
+                translog.getDeletionPolicy()
+                    .setLocalCheckpointOfSafeCommit(randomLongBetween(deletionPolicy.getLocalCheckpointOfSafeCommit(), i));
+            }
+            if (frequently()) {
+                long minGen;
+                try (Closeable ignored = translog.acquireRetentionLock()) {
+                    minGen = translog.getMinFileGeneration();
+                    assertThat(deletionPolicy.getTranslogRefCount(minGen), equalTo(1L));
+                }
+                assertThat(deletionPolicy.getTranslogRefCount(minGen), equalTo(0L));
+            }
+        }
+    }
+
+    public void testReadGlobalCheckpoint() throws Exception {
+        final String translogUUID = translog.getTranslogUUID();
+        globalCheckpoint.set(randomNonNegativeLong());
+        final int operations = randomIntBetween(1, 100);
+        for (int i = 0; i < operations; i++) {
+            translog.add(new Translog.NoOp(randomNonNegativeLong(), 0, "test'"));
+            if (rarely()) {
+                translog.rollGeneration();
+            }
+        }
+        translog.rollGeneration();
+        translog.close();
+        assertThat(Translog.readGlobalCheckpoint(translogDir, translogUUID), equalTo(globalCheckpoint.get()));
+        expectThrows(TranslogCorruptedException.class, () -> Translog.readGlobalCheckpoint(translogDir, UUIDs.randomBase64UUID()));
+    }
+
+    public void testSnapshotReadOperationInReverse() throws Exception {
+        final Deque<List<Translog.Operation>> views = new ArrayDeque<>();
+        views.push(new ArrayList<>());
+        final AtomicLong seqNo = new AtomicLong();
+
+        final int generations = randomIntBetween(2, 20);
+        for (int gen = 0; gen < generations; gen++) {
+            final int operations = randomIntBetween(1, 100);
+            for (int i = 0; i < operations; i++) {
+                Translog.Index op = new Translog.Index(
+                    randomAlphaOfLength(10),
+                    seqNo.getAndIncrement(),
+                    primaryTerm.get(),
+                    new byte[] { 1 }
+                );
+                translog.add(op);
+                views.peek().add(op);
+            }
+            if (frequently()) {
+                translog.rollGeneration();
+                views.push(new ArrayList<>());
+            }
+        }
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            final List<Translog.Operation> expectedSeqNo = new ArrayList<>();
+            while (views.isEmpty() == false) {
+                expectedSeqNo.addAll(views.pop());
+            }
+            assertThat(snapshot, SnapshotMatchers.equalsTo(expectedSeqNo));
+        }
+    }
+
+    public void testSnapshotDedupOperations() throws Exception {
+        final Map<Long, Translog.Operation> latestOperations = new HashMap<>();
+        final int generations = between(2, 20);
+        for (int gen = 0; gen < generations; gen++) {
+            List<Long> batch = LongStream.rangeClosed(0, between(0, 500)).boxed().collect(Collectors.toList());
+            Randomness.shuffle(batch);
+            for (Long seqNo : batch) {
+                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { 1 });
+                translog.add(op);
+                latestOperations.put(op.seqNo(), op);
+            }
+            translog.rollGeneration();
+        }
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, containsOperationsInAnyOrder(latestOperations.values()));
+        }
+    }
+
+    /** Make sure that it's ok to close a translog snapshot multiple times */
+    public void testCloseSnapshotTwice() throws Exception {
+        int numOps = between(0, 10);
+        for (int i = 0; i < numOps; i++) {
+            Translog.Index op = new Translog.Index(randomAlphaOfLength(10), i, primaryTerm.get(), new byte[] { 1 });
+            translog.add(op);
+            if (randomBoolean()) {
+                translog.rollGeneration();
+            }
+        }
+        for (int i = 0; i < 5; i++) {
+            Translog.Snapshot snapshot = translog.newSnapshot();
+            assertThat(snapshot, SnapshotMatchers.size(numOps));
+            snapshot.close();
+            snapshot.close();
+        }
+    }
+
+    // close method should never be called directly from Translog (the only exception is closeOnTragicEvent)
+    public void testTranslogCloseInvariant() throws IOException {
+        assumeTrue("test only works with assertions enabled", Assertions.ENABLED);
+        class MisbehavingTranslog extends LocalTranslog {
+            MisbehavingTranslog(
+                TranslogConfig config,
+                String translogUUID,
+                TranslogDeletionPolicy deletionPolicy,
+                LongSupplier globalCheckpointSupplier,
+                LongSupplier primaryTermSupplier
+            ) throws IOException {
+                super(config, translogUUID, deletionPolicy, globalCheckpointSupplier, primaryTermSupplier, seqNo -> {});
+            }
+
+            void callCloseDirectly() throws IOException {
+                close();
+            }
+
+            void callCloseUsingIOUtilsWithExceptionHandling() {
+                IOUtils.closeWhileHandlingException(this);
+            }
+
+            void callCloseUsingIOUtils() throws IOException {
+                IOUtils.close(this);
+            }
+
+            void callCloseOnTragicEvent() {
+                Exception e = new Exception("test tragic exception");
+                tragedy.setTragicException(e);
+                closeOnTragicEvent(e);
+            }
+        }
+
+        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        Path path = createTempDir();
+        final TranslogConfig translogConfig = getTranslogConfig(path);
+        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(translogConfig.getIndexSettings());
+        final String translogUUID = Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
+        MisbehavingTranslog misbehavingTranslog = new MisbehavingTranslog(
+            translogConfig,
+            translogUUID,
+            deletionPolicy,
+            () -> globalCheckpoint.get(),
+            primaryTerm::get
+        );
+
+        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseDirectly());
+        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseUsingIOUtils());
+        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseUsingIOUtilsWithExceptionHandling());
+        misbehavingTranslog.callCloseOnTragicEvent();
+    }
+
+    public void testMaxSeqNo() throws Exception {
+        Map<Long, Long> maxSeqNoPerGeneration = new HashMap<>();
+        for (int iterations = between(1, 10), i = 0; i < iterations; i++) {
+            long startSeqNo = randomLongBetween(0, Integer.MAX_VALUE);
+            List<Long> seqNos = LongStream.range(startSeqNo, startSeqNo + randomInt(100)).boxed().collect(Collectors.toList());
+            Randomness.shuffle(seqNos);
+            for (long seqNo : seqNos) {
+                if (frequently()) {
+                    translog.add(new Translog.Index("id", seqNo, primaryTerm.get(), new byte[] { 1 }));
+                    maxSeqNoPerGeneration.compute(
+                        translog.currentFileGeneration(),
+                        (key, existing) -> existing == null ? seqNo : Math.max(existing, seqNo)
+                    );
+                }
+            }
+            translog.rollGeneration();
+        }
+        translog.sync();
+        assertThat(
+            translog.getMaxSeqNo(),
+            equalTo(maxSeqNoPerGeneration.isEmpty() ? SequenceNumbers.NO_OPS_PERFORMED : Collections.max(maxSeqNoPerGeneration.values()))
+        );
+        long expectedMaxSeqNo = maxSeqNoPerGeneration.entrySet()
+            .stream()
+            .filter(e -> e.getKey() >= translog.getMinFileGeneration())
+            .mapToLong(e -> e.getValue())
+            .max()
+            .orElse(SequenceNumbers.NO_OPS_PERFORMED);
+        assertThat(translog.getMaxSeqNo(), equalTo(expectedMaxSeqNo));
+    }
+
+    public void testCrashDuringCheckpointCopy() throws IOException {
+        final Path path = createTempDir();
+        final AtomicBoolean failOnCopy = new AtomicBoolean();
+        final String expectedExceptionMessage = "simulated failure during copy";
+        final FilterFileSystemProvider filterFileSystemProvider = new FilterFileSystemProvider(
+            path.getFileSystem().provider().getScheme(),
+            path.getFileSystem()
+        ) {
+
+            @Override
+            public void copy(Path source, Path target, CopyOption... options) throws IOException {
+                if (failOnCopy.get() && source.toString().endsWith(Translog.CHECKPOINT_SUFFIX)) {
+                    deleteIfExists(target);
+                    Files.createFile(target);
+                    throw new IOException(expectedExceptionMessage);
+                } else {
+                    super.copy(source, target, options);
+                }
+            }
+        };
+
+        try (Translog brokenTranslog = create(filterFileSystemProvider.getPath(path.toUri()))) {
+            failOnCopy.set(true);
+            primaryTerm.incrementAndGet(); // increment primary term to force rolling generation
+            assertThat(expectThrows(IOException.class, brokenTranslog::rollGeneration).getMessage(), equalTo(expectedExceptionMessage));
+            assertFalse(brokenTranslog.isOpen());
+
+            try (
+                Translog recoveredTranslog = new LocalTranslog(
+                    getTranslogConfig(path),
+                    brokenTranslog.getTranslogUUID(),
+                    brokenTranslog.getDeletionPolicy(),
+                    () -> SequenceNumbers.NO_OPS_PERFORMED,
+                    primaryTerm::get,
+                    seqNo -> {}
+                )
+            ) {
+                recoveredTranslog.rollGeneration();
+                assertFilePresences(recoveredTranslog);
+            }
+        }
+    }
+
+    public void testSyncConcurrently() throws Exception {
+        Path path = createTempDir("translog");
+        TranslogConfig config = getTranslogConfig(path);
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            primaryTerm.get()
+        );
+        Set<Long> persistedSeqNos = ConcurrentCollections.newConcurrentSet();
+        AtomicLong lastGlobalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        LongSupplier globalCheckpointSupplier = () -> {
+            if (randomBoolean()) {
+                return lastGlobalCheckpoint.addAndGet(randomIntBetween(1, 100));
+            } else {
+                return lastGlobalCheckpoint.get();
+            }
+        };
+        try (
+            Translog translog = new LocalTranslog(
+                config,
+                translogUUID,
+                createTranslogDeletionPolicy(config.getIndexSettings()),
+                globalCheckpointSupplier,
+                primaryTerm::get,
+                persistedSeqNos::add
+            )
+        ) {
+            Thread[] threads = new Thread[between(2, 8)];
+            Phaser phaser = new Phaser(threads.length);
+            AtomicLong nextSeqNo = new AtomicLong();
+            for (int t = 0; t < threads.length; t++) {
+                threads[t] = new Thread(() -> {
+                    phaser.arriveAndAwaitAdvance();
+                    int iterations = randomIntBetween(10, 100);
+                    for (int i = 0; i < iterations; i++) {
+                        List<Translog.Operation> ops = IntStream.range(0, between(1, 10))
+                            .mapToObj(n -> new Translog.Index("1", nextSeqNo.incrementAndGet(), primaryTerm.get(), new byte[] { 1 }))
+                            .collect(Collectors.toList());
+                        try {
+                            Translog.Location location = null;
+                            for (Translog.Operation op : ops) {
+                                location = translog.add(op);
+                            }
+                            assertNotNull(location);
+                            long globalCheckpoint = lastGlobalCheckpoint.get();
+                            final boolean synced;
+                            if (randomBoolean()) {
+                                synced = translog.ensureSynced(location);
+                            } else {
+                                translog.sync();
+                                synced = true;
+                            }
+                            for (Translog.Operation op : ops) {
+                                assertThat("seq# " + op.seqNo() + " was not marked as persisted", persistedSeqNos, hasItem(op.seqNo()));
+                            }
+                            Checkpoint checkpoint = translog.getLastSyncedCheckpoint();
+                            assertThat(checkpoint.offset, greaterThanOrEqualTo(location.translogLocation));
+                            for (Translog.Operation op : ops) {
+                                assertThat(checkpoint.minSeqNo, lessThanOrEqualTo(op.seqNo()));
+                                assertThat(checkpoint.maxSeqNo, greaterThanOrEqualTo(op.seqNo()));
+                            }
+                            if (synced) {
+                                assertThat(checkpoint.globalCheckpoint, greaterThanOrEqualTo(globalCheckpoint));
+                            }
+                        } catch (Exception e) {
+                            throw new AssertionError(e);
+                        }
+                    }
+                });
+                threads[t].start();
+            }
+            for (Thread thread : threads) {
+                thread.join();
+            }
+        }
+    }
+
+    public void testEnsureNoCircularException() throws Exception {
+        final AtomicBoolean failedToSyncCheckpoint = new AtomicBoolean();
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            final FileChannel channel = FileChannel.open(file, openOption);
+            return new FilterFileChannel(channel) {
+                @Override
+                public void force(boolean metaData) throws IOException {
+                    if (failedToSyncCheckpoint.get()) {
+                        throw new IOException("simulated");
+                    }
+                    super.force(metaData);
+                }
+            };
+        };
+        final TranslogConfig config = getTranslogConfig(createTempDir());
+        final String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+        final Translog translog = new LocalTranslog(
+            config,
+            translogUUID,
+            createTranslogDeletionPolicy(),
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTerm::get,
+            seqNo -> {}
+        ) {
+            @Override
+            ChannelFactory getChannelFactory() {
+                return channelFactory;
+            }
+
+            @Override
+            void syncBeforeRollGeneration() {
+                // make it a noop like the old versions
+            }
+        };
+        try {
+            translog.add(new Translog.Index("1", 1, primaryTerm.get(), new byte[] { 1 }));
+            failedToSyncCheckpoint.set(true);
+            expectThrows(IOException.class, translog::rollGeneration);
+            final AlreadyClosedException alreadyClosedException = expectThrows(AlreadyClosedException.class, translog::rollGeneration);
+            if (hasCircularReference(alreadyClosedException)) {
+                throw new AssertionError("detect circular reference exception", alreadyClosedException);
+            }
+        } finally {
+            IOUtils.close(translog);
+        }
+    }
+
+    static boolean hasCircularReference(Exception cause) {
+        final Queue<Throwable> queue = new LinkedList<>();
+        queue.add(cause);
+        final Set<Throwable> seen = Collections.newSetFromMap(new IdentityHashMap<>());
+        while (queue.isEmpty() == false) {
+            final Throwable current = queue.remove();
+            if (seen.add(current) == false) {
+                return true;
+            }
+            Collections.addAll(queue, current.getSuppressed());
+            if (current.getCause() != null) {
+                queue.add(current.getCause());
+            }
+        }
+        return false;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/MultiSnapshotTests.java b/server/src/test/java/org/opensearch/index/translog/MultiSnapshotTests.java
index 783c42f1749c0..b5bef0c028665 100644
--- a/server/src/test/java/org/opensearch/index/translog/MultiSnapshotTests.java
+++ b/server/src/test/java/org/opensearch/index/translog/MultiSnapshotTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.index.translog;
 
-import com.carrotsearch.hppc.LongHashSet;
-import com.carrotsearch.hppc.LongSet;
 import org.opensearch.common.Randomness;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.LongStream;
@@ -60,7 +60,7 @@ public void testTrackSeqNoSimpleRange() throws Exception {
 
     public void testTrackSeqNoDenseRanges() throws Exception {
         final MultiSnapshot.SeqNoSet bitSet = new MultiSnapshot.SeqNoSet();
-        final LongSet normalSet = new LongHashSet();
+        final Set<Long> normalSet = new HashSet<>();
         IntStream.range(0, scaledRandomIntBetween(5_000, 10_000)).forEach(i -> {
             long seq = between(0, 5000);
             boolean existed = normalSet.add(seq) == false;
@@ -70,7 +70,7 @@ public void testTrackSeqNoDenseRanges() throws Exception {
 
     public void testTrackSeqNoSparseRanges() throws Exception {
         final MultiSnapshot.SeqNoSet bitSet = new MultiSnapshot.SeqNoSet();
-        final LongSet normalSet = new LongHashSet();
+        final Set<Long> normalSet = new HashSet<>();
         IntStream.range(0, scaledRandomIntBetween(5_000, 10_000)).forEach(i -> {
             long seq = between(i * 10_000, i * 30_000);
             boolean existed = normalSet.add(seq) == false;
@@ -80,7 +80,7 @@ public void testTrackSeqNoSparseRanges() throws Exception {
 
     public void testTrackSeqNoMimicTranslogRanges() throws Exception {
         final MultiSnapshot.SeqNoSet bitSet = new MultiSnapshot.SeqNoSet();
-        final LongSet normalSet = new LongHashSet();
+        final Set<Long> normalSet = new HashSet<>();
         long currentSeq = between(10_000_000, 1_000_000_000);
         final int iterations = scaledRandomIntBetween(100, 2000);
         for (long i = 0; i < iterations; i++) {
diff --git a/server/src/test/java/org/opensearch/index/translog/RemoteFsTranslogTests.java b/server/src/test/java/org/opensearch/index/translog/RemoteFsTranslogTests.java
new file mode 100644
index 0000000000000..b2310010620f7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/RemoteFsTranslogTests.java
@@ -0,0 +1,1684 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.apache.lucene.backward_codecs.store.EndiannessReverserUtil;
+import org.apache.lucene.store.AlreadyClosedException;
+import org.apache.lucene.store.ByteArrayDataOutput;
+import org.apache.lucene.store.DataOutput;
+import org.apache.lucene.tests.mockfile.FilterFileChannel;
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.OpenSearchException;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.fs.FsBlobContainer;
+import org.opensearch.common.blobstore.fs.FsBlobStore;
+import org.opensearch.common.bytes.ReleasableBytesReference;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.AbstractRunnable;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.env.TestEnvironment;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.MissingHistoryOperationsException;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.seqno.LocalCheckpointTracker;
+import org.opensearch.index.seqno.LocalCheckpointTrackerTests;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.transfer.BlobStoreTransferService;
+import org.opensearch.index.translog.transfer.TranslogTransferManager;
+import org.opensearch.index.translog.transfer.TranslogTransferMetadata;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.Closeable;
+import java.io.EOFException;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.LongConsumer;
+import java.util.zip.CRC32;
+import java.util.zip.CheckedInputStream;
+
+import static org.opensearch.common.util.BigArrays.NON_RECYCLING_INSTANCE;
+import static org.opensearch.index.translog.RemoteFsTranslog.TRANSLOG;
+import static org.opensearch.index.translog.SnapshotMatchers.containsOperationsInAnyOrder;
+import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+@LuceneTestCase.SuppressFileSystems("ExtrasFS")
+public class RemoteFsTranslogTests extends OpenSearchTestCase {
+
+    protected final ShardId shardId = new ShardId("index", "_na_", 1);
+
+    protected RemoteFsTranslog translog;
+    private AtomicLong globalCheckpoint;
+    protected Path translogDir;
+    // A default primary term is used by translog instances created in this test.
+    private final AtomicLong primaryTerm = new AtomicLong();
+    private final AtomicBoolean primaryMode = new AtomicBoolean(true);
+    private final AtomicReference<LongConsumer> persistedSeqNoConsumer = new AtomicReference<>();
+    private ThreadPool threadPool;
+    private final static String METADATA_DIR = "metadata";
+    private final static String DATA_DIR = "data";
+    BlobStoreRepository repository;
+
+    BlobStoreTransferService blobStoreTransferService;
+
+    TestTranslog.FailSwitch fail;
+
+    private LongConsumer getPersistedSeqNoConsumer() {
+        return seqNo -> {
+            final LongConsumer consumer = persistedSeqNoConsumer.get();
+            if (consumer != null) {
+                consumer.accept(seqNo);
+            }
+        };
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        primaryTerm.set(randomLongBetween(1, Integer.MAX_VALUE));
+        // if a previous test failed we clean up things here
+        translogDir = createTempDir();
+        translog = create(translogDir);
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        try {
+            translog.getDeletionPolicy().assertNoOpenTranslogRefs();
+            translog.close();
+        } finally {
+            super.tearDown();
+            terminate(threadPool);
+        }
+    }
+
+    private RemoteFsTranslog create(Path path) throws IOException {
+        final String translogUUID = Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
+        return create(path, createRepository(), translogUUID);
+    }
+
+    private RemoteFsTranslog create(Path path, BlobStoreRepository repository, String translogUUID) throws IOException {
+        this.repository = repository;
+        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final TranslogConfig translogConfig = getTranslogConfig(path);
+        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(translogConfig.getIndexSettings());
+        threadPool = new TestThreadPool(getClass().getName());
+        blobStoreTransferService = new BlobStoreTransferService(repository.blobStore(), threadPool);
+        return new RemoteFsTranslog(
+            translogConfig,
+            translogUUID,
+            deletionPolicy,
+            () -> globalCheckpoint.get(),
+            primaryTerm::get,
+            getPersistedSeqNoConsumer(),
+            repository,
+            threadPool,
+            primaryMode::get,
+            new RemoteTranslogTransferTracker(shardId, 10)
+        );
+
+    }
+
+    private TranslogConfig getTranslogConfig(final Path path) {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            // only randomize between nog age retention and a long one, so failures will have a chance of reproducing
+            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_AGE_SETTING.getKey(), randomBoolean() ? "-1ms" : "1h")
+            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_SIZE_SETTING.getKey(), randomIntBetween(-1, 2048) + "b")
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .build();
+        return getTranslogConfig(path, settings);
+    }
+
+    private TranslogConfig getTranslogConfig(final Path path, final Settings settings) {
+        final ByteSizeValue bufferSize = randomFrom(
+            TranslogConfig.DEFAULT_BUFFER_SIZE,
+            new ByteSizeValue(8, ByteSizeUnit.KB),
+            new ByteSizeValue(10 + randomInt(128 * 1024), ByteSizeUnit.BYTES)
+        );
+
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(shardId.getIndex(), settings);
+        return new TranslogConfig(shardId, path, indexSettings, NON_RECYCLING_INSTANCE, bufferSize, "");
+    }
+
+    private BlobStoreRepository createRepository() {
+        Settings settings = Settings.builder().put("location", randomAlphaOfLength(10)).build();
+        RepositoryMetadata repositoryMetadata = new RepositoryMetadata(randomAlphaOfLength(10), FsRepository.TYPE, settings);
+        final ClusterService clusterService = BlobStoreTestUtil.mockClusterService(repositoryMetadata);
+        fail = new TestTranslog.FailSwitch();
+        fail.failNever();
+        final FsRepository repository = new ThrowingBlobRepository(
+            repositoryMetadata,
+            createEnvironment(),
+            xContentRegistry(),
+            clusterService,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            fail
+        ) {
+            @Override
+            protected void assertSnapshotOrGenericThread() {
+                // eliminate thread name check as we create repo manually
+            }
+        };
+        clusterService.addStateApplier(event -> repository.updateState(event.state()));
+        // Apply state once to initialize repo properly like RepositoriesService would
+        repository.updateState(clusterService.state());
+        repository.start();
+        return repository;
+    }
+
+    /** Create a {@link Environment} with random path.home and path.repo **/
+    private Environment createEnvironment() {
+        Path home = createTempDir();
+        return TestEnvironment.newEnvironment(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), home.toAbsolutePath())
+                .put(Environment.PATH_REPO_SETTING.getKey(), home.resolve("repo").toAbsolutePath())
+                .build()
+        );
+    }
+
+    private Translog.Location addToTranslogAndList(Translog translog, List<Translog.Operation> list, Translog.Operation op)
+        throws IOException {
+        Translog.Location loc = translog.add(op);
+        Random random = random();
+        if (random.nextBoolean()) {
+            translog.ensureSynced(loc);
+        }
+        list.add(op);
+        return loc;
+    }
+
+    private Translog.Location addToTranslogAndListAndUpload(Translog translog, List<Translog.Operation> list, Translog.Operation op)
+        throws IOException {
+        Translog.Location loc = translog.add(op);
+        translog.ensureSynced(loc);
+        list.add(op);
+        return loc;
+    }
+
+    private static void assertUploadStatsNoFailures(RemoteTranslogTransferTracker statsTracker) {
+        assertTrue(statsTracker.getUploadBytesStarted() > 0);
+        assertTrue(statsTracker.getTotalUploadsStarted() > 0);
+        assertEquals(0, statsTracker.getUploadBytesFailed());
+        assertEquals(0, statsTracker.getTotalUploadsFailed());
+        assertTrue(statsTracker.getUploadBytesSucceeded() > 0);
+        assertTrue(statsTracker.getTotalUploadsSucceeded() > 0);
+        assertTrue(statsTracker.getTotalUploadTimeInMillis() > 0);
+        assertTrue(statsTracker.getLastSuccessfulUploadTimestamp() > 0);
+    }
+
+    private static void assertUploadStatsNoUploads(RemoteTranslogTransferTracker statsTracker) {
+        assertEquals(0, statsTracker.getUploadBytesStarted());
+        assertEquals(0, statsTracker.getUploadBytesFailed());
+        assertEquals(0, statsTracker.getUploadBytesSucceeded());
+        assertEquals(0, statsTracker.getTotalUploadsStarted());
+        assertEquals(0, statsTracker.getTotalUploadsFailed());
+        assertEquals(0, statsTracker.getTotalUploadsSucceeded());
+        assertEquals(0, statsTracker.getTotalUploadTimeInMillis());
+        assertEquals(0, statsTracker.getLastSuccessfulUploadTimestamp());
+    }
+
+    private static void assertDownloadStatsPopulated(RemoteTranslogTransferTracker statsTracker) {
+        assertTrue(statsTracker.getDownloadBytesSucceeded() > 0);
+        assertTrue(statsTracker.getTotalDownloadsSucceeded() > 0);
+        // TODO: Need to simulate a delay for this assertion to avoid flakiness
+        // assertTrue(statsTracker.getTotalDownloadTimeInMillis() > 0);
+        assertTrue(statsTracker.getLastSuccessfulDownloadTimestamp() > 0);
+    }
+
+    private static void assertDownloadStatsNoDownloads(RemoteTranslogTransferTracker statsTracker) {
+        assertEquals(0, statsTracker.getDownloadBytesSucceeded());
+        assertEquals(0, statsTracker.getTotalDownloadsSucceeded());
+        assertEquals(0, statsTracker.getTotalDownloadTimeInMillis());
+        assertEquals(0, statsTracker.getLastSuccessfulDownloadTimestamp());
+    }
+
+    public void testUploadWithPrimaryModeFalse() {
+        // Test setup
+        primaryMode.set(false);
+
+        // Validate
+        assertTrue(translog.syncNeeded());
+        assertFalse(primaryMode.get());
+        try {
+            translog.sync();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        assertTrue(translog.syncNeeded());
+        RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+        assertUploadStatsNoUploads(statsTracker);
+        assertDownloadStatsNoDownloads(statsTracker);
+    }
+
+    public void testUploadWithPrimaryModeTrue() {
+        // Validate
+        assertTrue(translog.syncNeeded());
+        assertTrue(primaryMode.get());
+        try {
+            translog.sync();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        assertFalse(translog.syncNeeded());
+        RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+        assertUploadStatsNoFailures(statsTracker);
+        assertDownloadStatsNoDownloads(statsTracker);
+    }
+
+    public void testSimpleOperations() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+        }
+
+        addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        addToTranslogAndList(translog, ops, new Translog.Delete("2", 1, primaryTerm.get()));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+            assertThat(snapshot, containsOperationsInAnyOrder(ops));
+        }
+
+        final long seqNo = randomLongBetween(0, Integer.MAX_VALUE);
+        final String reason = randomAlphaOfLength(16);
+        final long noopTerm = randomLongBetween(1, primaryTerm.get());
+        addToTranslogAndList(translog, ops, new Translog.NoOp(seqNo, noopTerm, reason));
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, containsOperationsInAnyOrder(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        try (Translog.Snapshot snapshot = translog.newSnapshot(seqNo + 1, randomLongBetween(seqNo + 1, Long.MAX_VALUE))) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+            assertThat(snapshot.totalOperations(), equalTo(0));
+        }
+
+    }
+
+    public void testReadLocation() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        ArrayList<Translog.Location> locs = new ArrayList<>();
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 1 })));
+        translog.sync();
+        int i = 0;
+        for (Translog.Operation op : ops) {
+            assertEquals(op, translog.readOperation(locs.get(i++)));
+        }
+        assertNull(translog.readOperation(new Translog.Location(100, 0, 0)));
+        RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+        assertUploadStatsNoFailures(statsTracker);
+        assertDownloadStatsNoDownloads(statsTracker);
+    }
+
+    public void testReadLocationDownload() throws IOException {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        ArrayList<Translog.Location> locs = new ArrayList<>();
+        locs.add(addToTranslogAndListAndUpload(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndListAndUpload(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 1 })));
+        locs.add(addToTranslogAndListAndUpload(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 1 })));
+
+        translog.sync();
+        int i = 0;
+        for (Translog.Operation op : ops) {
+            assertEquals(op, translog.readOperation(locs.get(i++)));
+        }
+
+        RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+        assertUploadStatsNoFailures(statsTracker);
+        assertDownloadStatsNoDownloads(statsTracker);
+
+        String translogUUID = translog.translogUUID;
+        try {
+            translog.getDeletionPolicy().assertNoOpenTranslogRefs();
+            translog.close();
+        } finally {
+            terminate(threadPool);
+        }
+
+        // Delete translog files to test download flow
+        for (Path file : FileSystemUtils.files(translogDir)) {
+            Files.delete(file);
+        }
+
+        // Creating RemoteFsTranslog with the same location
+        RemoteFsTranslog newTranslog = create(translogDir, repository, translogUUID);
+        i = 0;
+        for (Translog.Operation op : ops) {
+            assertEquals(op, newTranslog.readOperation(locs.get(i++)));
+        }
+
+        statsTracker = newTranslog.getRemoteTranslogTracker();
+        assertUploadStatsNoUploads(statsTracker);
+        assertDownloadStatsPopulated(statsTracker);
+
+        try {
+            newTranslog.close();
+        } catch (Exception e) {
+            // Ignoring this exception for now. Once the download flow populates FileTracker,
+            // we can remove this try-catch block
+        }
+    }
+
+    public void testSnapshotWithNewTranslog() throws IOException {
+        List<Closeable> toClose = new ArrayList<>();
+        try {
+            ArrayList<Translog.Operation> ops = new ArrayList<>();
+            Translog.Snapshot snapshot = translog.newSnapshot();
+            toClose.add(snapshot);
+            assertThat(snapshot, SnapshotMatchers.size(0));
+
+            addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+            Translog.Snapshot snapshot1 = translog.newSnapshot();
+            toClose.add(snapshot1);
+
+            addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 2 }));
+
+            assertThat(snapshot1, SnapshotMatchers.equalsTo(ops.get(0)));
+
+            translog.rollGeneration();
+            addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 3 }));
+
+            Translog.Snapshot snapshot2 = translog.newSnapshot();
+            toClose.add(snapshot2);
+            translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(2);
+            assertThat(snapshot2, containsOperationsInAnyOrder(ops));
+            assertThat(snapshot2.totalOperations(), equalTo(ops.size()));
+        } finally {
+            IOUtils.closeWhileHandlingException(toClose);
+        }
+    }
+
+    public void testSnapshotOnClosedTranslog() throws IOException {
+        assertTrue(Files.exists(translogDir.resolve(Translog.getFilename(1))));
+        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        translog.close();
+        AlreadyClosedException ex = expectThrows(AlreadyClosedException.class, () -> translog.newSnapshot());
+        assertEquals(ex.getMessage(), "translog is already closed");
+    }
+
+    public void testRangeSnapshot() throws Exception {
+        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        final int generations = between(2, 20);
+        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
+        for (int gen = 0; gen < generations; gen++) {
+            Set<Long> seqNos = new HashSet<>();
+            int numOps = randomIntBetween(1, 100);
+            for (int i = 0; i < numOps; i++) {
+                final long seqNo = randomValueOtherThanMany(seqNos::contains, () -> randomLongBetween(0, 1000));
+                minSeqNo = SequenceNumbers.min(minSeqNo, seqNo);
+                maxSeqNo = SequenceNumbers.max(maxSeqNo, seqNo);
+                seqNos.add(seqNo);
+            }
+            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
+            for (long seqNo : seqNos) {
+                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
+                translog.add(op);
+                ops.add(op);
+            }
+            operationsByGen.put(translog.currentFileGeneration(), ops);
+            translog.rollGeneration();
+            if (rarely()) {
+                translog.rollGeneration(); // empty generation
+            }
+        }
+
+        if (minSeqNo > 0) {
+            long fromSeqNo = randomLongBetween(0, minSeqNo - 1);
+            long toSeqNo = randomLongBetween(fromSeqNo, minSeqNo - 1);
+            try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+                assertThat(snapshot.totalOperations(), equalTo(0));
+                assertNull(snapshot.next());
+            }
+        }
+
+        long fromSeqNo = randomLongBetween(maxSeqNo + 1, Long.MAX_VALUE);
+        long toSeqNo = randomLongBetween(fromSeqNo, Long.MAX_VALUE);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+            assertThat(snapshot.totalOperations(), equalTo(0));
+            assertNull(snapshot.next());
+        }
+
+        fromSeqNo = randomLongBetween(0, 2000);
+        toSeqNo = randomLongBetween(fromSeqNo, 2000);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
+            Set<Long> seenSeqNos = new HashSet<>();
+            List<Translog.Operation> expectedOps = new ArrayList<>();
+            for (long gen = translog.currentFileGeneration(); gen > 0; gen--) {
+                for (Translog.Operation op : operationsByGen.getOrDefault(gen, Collections.emptyList())) {
+                    if (fromSeqNo <= op.seqNo() && op.seqNo() <= toSeqNo && seenSeqNos.add(op.seqNo())) {
+                        expectedOps.add(op);
+                    }
+                }
+            }
+            assertThat(TestTranslog.drainSnapshot(snapshot, false), equalTo(expectedOps));
+        }
+    }
+
+    public void testSimpleOperationsUpload() throws Exception {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.size(0));
+        }
+
+        addToTranslogAndListAndUpload(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
+            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
+        }
+
+        assertEquals(4, translog.allUploaded().size());
+
+        addToTranslogAndListAndUpload(translog, ops, new Translog.Index("1", 1, primaryTerm.get(), new byte[] { 1 }));
+        assertEquals(6, translog.allUploaded().size());
+
+        translog.rollGeneration();
+        assertEquals(6, translog.allUploaded().size());
+
+        Set<String> mdFiles = blobStoreTransferService.listAll(getTranslogDirectory().add(METADATA_DIR));
+        assertEquals(2, mdFiles.size());
+        logger.info("All md files {}", mdFiles);
+
+        Set<String> tlogFiles = blobStoreTransferService.listAll(
+            getTranslogDirectory().add(DATA_DIR).add(String.valueOf(primaryTerm.get()))
+        );
+        logger.info("All data files {}", tlogFiles);
+
+        // assert content of ckp and tlog files
+        BlobPath path = getTranslogDirectory().add(DATA_DIR).add(String.valueOf(primaryTerm.get()));
+        for (TranslogReader reader : translog.readers) {
+            final long readerGeneration = reader.getGeneration();
+            logger.error("Asserting content of {}", readerGeneration);
+            Path translogPath = reader.path();
+            try (
+                InputStream stream = new CheckedInputStream(Files.newInputStream(translogPath), new CRC32());
+                InputStream tlogStream = blobStoreTransferService.downloadBlob(path, Translog.getFilename(readerGeneration));
+            ) {
+                byte[] content = stream.readAllBytes();
+                byte[] tlog = tlogStream.readAllBytes();
+                assertArrayEquals(tlog, content);
+            }
+
+            Path checkpointPath = translog.location().resolve(Translog.getCommitCheckpointFileName(readerGeneration));
+            try (
+                CheckedInputStream stream = new CheckedInputStream(Files.newInputStream(checkpointPath), new CRC32());
+                InputStream ckpStream = blobStoreTransferService.downloadBlob(path, Translog.getCommitCheckpointFileName(readerGeneration))
+            ) {
+                byte[] content = stream.readAllBytes();
+                byte[] ckp = ckpStream.readAllBytes();
+                assertArrayEquals(ckp, content);
+            }
+        }
+
+        // expose the new checkpoint (simulating a commit), before we trim the translog
+        // simulating the remote segment upload .
+        translog.setMinSeqNoToKeep(0);
+        // This should not trim anything from local
+        translog.trimUnreferencedReaders();
+        assertEquals(2, translog.readers.size());
+        assertBusy(() -> {
+            assertEquals(4, translog.allUploaded().size());
+            assertEquals(
+                4,
+                blobStoreTransferService.listAll(getTranslogDirectory().add(DATA_DIR).add(String.valueOf(primaryTerm.get()))).size()
+            );
+        });
+
+        // This should trim tlog-2 from local
+        // This should not trim tlog-2.* files from remote as we not uploading any more translog to remote
+        translog.setMinSeqNoToKeep(1);
+        translog.trimUnreferencedReaders();
+        assertEquals(1, translog.readers.size());
+        assertBusy(() -> {
+            assertEquals(4, translog.allUploaded().size());
+            assertEquals(
+                4,
+                blobStoreTransferService.listAll(getTranslogDirectory().add(DATA_DIR).add(String.valueOf(primaryTerm.get()))).size()
+            );
+        });
+
+        // this should now trim as tlog-2 files from remote, but not tlog-3 and tlog-4
+        addToTranslogAndListAndUpload(translog, ops, new Translog.Index("2", 2, primaryTerm.get(), new byte[] { 1 }));
+        assertEquals(2, translog.stats().estimatedNumberOfOperations());
+
+        translog.setMinSeqNoToKeep(2);
+
+        assertBusy(() -> assertTrue(translog.isRemoteGenerationDeletionPermitsAvailable()));
+        translog.trimUnreferencedReaders();
+        assertEquals(1, translog.readers.size());
+        assertEquals(1, translog.stats().estimatedNumberOfOperations());
+        assertBusy(() -> assertEquals(4, translog.allUploaded().size()));
+    }
+
+    public void testMetadataFileDeletion() throws Exception {
+        ArrayList<Translog.Operation> ops = new ArrayList<>();
+        // Test deletion of metadata files
+        int numDocs = randomIntBetween(6, 10);
+        for (int i = 0; i < numDocs; i++) {
+            addToTranslogAndListAndUpload(translog, ops, new Translog.Index(String.valueOf(i), i, primaryTerm.get(), new byte[] { 1 }));
+            translog.setMinSeqNoToKeep(i);
+            translog.trimUnreferencedReaders();
+            assertEquals(1, translog.readers.size());
+        }
+        assertBusy(() -> assertEquals(4, translog.allUploaded().size()));
+        assertBusy(() -> assertEquals(1, blobStoreTransferService.listAll(getTranslogDirectory().add(METADATA_DIR)).size()));
+        int moreDocs = randomIntBetween(3, 10);
+        logger.info("numDocs={} moreDocs={}", numDocs, moreDocs);
+        for (int i = numDocs; i < numDocs + moreDocs; i++) {
+            addToTranslogAndListAndUpload(translog, ops, new Translog.Index(String.valueOf(i), i, primaryTerm.get(), new byte[] { 1 }));
+        }
+        translog.trimUnreferencedReaders();
+        assertEquals(1 + moreDocs, translog.readers.size());
+        assertBusy(() -> assertEquals(2 + 2L * moreDocs, translog.allUploaded().size()));
+        assertBusy(() -> assertEquals(1, blobStoreTransferService.listAll(getTranslogDirectory().add(METADATA_DIR)).size()));
+
+        int totalDocs = numDocs + moreDocs;
+        translog.setMinSeqNoToKeep(totalDocs - 1);
+        translog.trimUnreferencedReaders();
+
+        addToTranslogAndListAndUpload(
+            translog,
+            ops,
+            new Translog.Index(String.valueOf(totalDocs), totalDocs, primaryTerm.get(), new byte[] { 1 })
+        );
+        translog.setMinSeqNoToKeep(totalDocs);
+        translog.trimUnreferencedReaders();
+        assertBusy(() -> assertEquals(1, blobStoreTransferService.listAll(getTranslogDirectory().add(METADATA_DIR)).size()));
+
+        // Change primary term and test the deletion of older primaries
+        String translogUUID = translog.translogUUID;
+        try {
+            translog.getDeletionPolicy().assertNoOpenTranslogRefs();
+            translog.close();
+        } finally {
+            terminate(threadPool);
+        }
+
+        // Increase primary term
+        long oldPrimaryTerm = primaryTerm.get();
+        long newPrimaryTerm = primaryTerm.incrementAndGet();
+
+        // Creating RemoteFsTranslog with the same location
+        Translog newTranslog = create(translogDir, repository, translogUUID);
+        int newPrimaryTermDocs = randomIntBetween(5, 10);
+        for (int i = totalDocs + 1; i <= totalDocs + newPrimaryTermDocs; i++) {
+            addToTranslogAndListAndUpload(newTranslog, ops, new Translog.Index(String.valueOf(i), i, primaryTerm.get(), new byte[] { 1 }));
+            // newTranslog.deletionPolicy.setLocalCheckpointOfSafeCommit(i - 1);
+            newTranslog.setMinSeqNoToKeep(i);
+            newTranslog.trimUnreferencedReaders();
+        }
+
+        try {
+            newTranslog.close();
+        } catch (Exception e) {
+            // Ignoring this exception for now. Once the download flow populates FileTracker,
+            // we can remove this try-catch block
+        }
+    }
+
+    private BlobPath getTranslogDirectory() {
+        return repository.basePath().add(shardId.getIndex().getUUID()).add(String.valueOf(shardId.id())).add(TRANSLOG);
+    }
+
+    private Long populateTranslogOps(boolean withMissingOps) throws IOException {
+        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
+        final int generations = between(2, 20);
+        long currentSeqNo = 0L;
+        List<Translog.Operation> firstGenOps = null;
+        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
+        for (int gen = 0; gen < generations; gen++) {
+            List<Long> seqNos = new ArrayList<>();
+            int numOps = randomIntBetween(4, 10);
+            for (int i = 0; i < numOps; i++, currentSeqNo++) {
+                minSeqNo = SequenceNumbers.min(minSeqNo, currentSeqNo);
+                maxSeqNo = SequenceNumbers.max(maxSeqNo, currentSeqNo);
+                seqNos.add(currentSeqNo);
+            }
+            Collections.shuffle(seqNos, new Random(100));
+            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
+            for (long seqNo : seqNos) {
+                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
+                boolean shouldAdd = !withMissingOps || seqNo % 4 != 0;
+                if (shouldAdd) {
+                    translog.add(op);
+                    ops.add(op);
+                }
+            }
+            operationsByGen.put(translog.currentFileGeneration(), ops);
+            if (firstGenOps == null) {
+                firstGenOps = ops;
+            }
+            translog.rollGeneration();
+            if (rarely()) {
+                translog.rollGeneration(); // empty generation
+            }
+        }
+        return currentSeqNo;
+    }
+
+    public void testFullRangeSnapshot() throws Exception {
+        // Successful snapshot
+        long nextSeqNo = populateTranslogOps(false);
+        long fromSeqNo = 0L;
+        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
+            int totOps = 0;
+            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
+                totOps++;
+            }
+            assertEquals(totOps, toSeqNo - fromSeqNo + 1);
+        }
+    }
+
+    public void testFullRangeSnapshotWithFailures() throws Exception {
+        long nextSeqNo = populateTranslogOps(true);
+        long fromSeqNo = 0L;
+        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
+        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
+            int totOps = 0;
+            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
+                totOps++;
+            }
+            fail("Should throw exception for missing operations");
+        } catch (MissingHistoryOperationsException e) {
+            assertTrue(e.getMessage().contains("Not all operations between from_seqno"));
+        }
+    }
+
+    public void testConcurrentWritesWithVaryingSize() throws Throwable {
+        final int opsPerThread = randomIntBetween(10, 200);
+        int threadCount = 2 + randomInt(5);
+
+        logger.info("testing with [{}] threads, each doing [{}] ops", threadCount, opsPerThread);
+        final BlockingQueue<TestTranslog.LocationOperation> writtenOperations = new ArrayBlockingQueue<>(threadCount * opsPerThread);
+
+        Thread[] threads = new Thread[threadCount];
+        final Exception[] threadExceptions = new Exception[threadCount];
+        final AtomicLong seqNoGenerator = new AtomicLong();
+        final CountDownLatch downLatch = new CountDownLatch(1);
+        for (int i = 0; i < threadCount; i++) {
+            final int threadId = i;
+            threads[i] = new TranslogThread(
+                translog,
+                downLatch,
+                opsPerThread,
+                threadId,
+                writtenOperations,
+                seqNoGenerator,
+                threadExceptions
+            );
+            threads[i].setDaemon(true);
+            threads[i].start();
+        }
+
+        downLatch.countDown();
+
+        for (int i = 0; i < threadCount; i++) {
+            if (threadExceptions[i] != null) {
+                throw threadExceptions[i];
+            }
+            threads[i].join(60 * 1000);
+        }
+
+        List<TestTranslog.LocationOperation> collect = new ArrayList<>(writtenOperations);
+        collect.sort(Comparator.comparing(op -> op.operation.seqNo()));
+
+        List<Translog.Operation> opsList = new ArrayList<>(threadCount * opsPerThread);
+        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
+            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
+                opsList.add(op);
+            }
+        }
+        opsList.sort(Comparator.comparing(op -> op.seqNo()));
+
+        for (int i = 0; i < threadCount * opsPerThread; i++) {
+            assertEquals(opsList.get(i), collect.get(i).operation);
+        }
+    }
+
+    /**
+     * Tests that concurrent readers and writes maintain view and snapshot semantics
+     */
+    public void testConcurrentWriteViewsAndSnapshot() throws Throwable {
+        final Thread[] writers = new Thread[randomIntBetween(1, 3)];
+        final Thread[] readers = new Thread[randomIntBetween(1, 3)];
+        final int flushEveryOps = randomIntBetween(5, 10);
+        final int maxOps = randomIntBetween(20, 100);
+        final Object signalReaderSomeDataWasIndexed = new Object();
+        final AtomicLong idGenerator = new AtomicLong();
+        final CyclicBarrier barrier = new CyclicBarrier(writers.length + readers.length + 1);
+
+        // a map of all written ops and their returned location.
+        final Map<Translog.Operation, Translog.Location> writtenOps = ConcurrentCollections.newConcurrentMap();
+
+        // a signal for all threads to stop
+        final AtomicBoolean run = new AtomicBoolean(true);
+
+        final Object flushMutex = new Object();
+        final AtomicLong lastCommittedLocalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        final LocalCheckpointTracker tracker = LocalCheckpointTrackerTests.createEmptyTracker();
+        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
+        // any errors on threads
+        final List<Exception> errors = new CopyOnWriteArrayList<>();
+        logger.info("using [{}] readers. [{}] writers. flushing every ~[{}] ops.", readers.length, writers.length, flushEveryOps);
+        for (int i = 0; i < writers.length; i++) {
+            final String threadName = "writer_" + i;
+            final int threadId = i;
+            writers[i] = new Thread(new AbstractRunnable() {
+                @Override
+                public void doRun() throws BrokenBarrierException, InterruptedException, IOException {
+                    barrier.await();
+                    int counter = 0;
+                    while (run.get() && idGenerator.get() < maxOps) {
+                        long id = idGenerator.getAndIncrement();
+                        final Translog.Operation op;
+                        final Translog.Operation.Type type = Translog.Operation.Type.values()[((int) (id % Translog.Operation.Type
+                            .values().length))];
+                        switch (type) {
+                            case CREATE:
+                            case INDEX:
+                                op = new Translog.Index("" + id, id, primaryTerm.get(), new byte[] { (byte) id });
+                                break;
+                            case DELETE:
+                                op = new Translog.Delete(Long.toString(id), id, primaryTerm.get());
+                                break;
+                            case NO_OP:
+                                op = new Translog.NoOp(id, 1, Long.toString(id));
+                                break;
+                            default:
+                                throw new AssertionError("unsupported operation type [" + type + "]");
+                        }
+                        Translog.Location location = translog.add(op);
+                        tracker.markSeqNoAsProcessed(id);
+                        Translog.Location existing = writtenOps.put(op, location);
+                        if (existing != null) {
+                            fail("duplicate op [" + op + "], old entry at " + location);
+                        }
+                        if (id % writers.length == threadId) {
+                            translog.ensureSynced(location);
+                        }
+                        if (id % flushEveryOps == 0) {
+                            synchronized (flushMutex) {
+                                // we need not do this concurrently as we need to make sure that the generation
+                                // we're committing - is still present when we're committing
+                                long localCheckpoint = tracker.getProcessedCheckpoint();
+                                translog.rollGeneration();
+                                // expose the new checkpoint (simulating a commit), before we trim the translog
+                                lastCommittedLocalCheckpoint.set(localCheckpoint);
+                                // deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
+                                translog.setMinSeqNoToKeep(localCheckpoint + 1);
+                                translog.trimUnreferencedReaders();
+                            }
+                        }
+                        if (id % 7 == 0) {
+                            synchronized (signalReaderSomeDataWasIndexed) {
+                                signalReaderSomeDataWasIndexed.notifyAll();
+                            }
+                        }
+                        counter++;
+                    }
+                    logger.info("--> [{}] done. wrote [{}] ops.", threadName, counter);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(() -> new ParameterizedMessage("--> writer [{}] had an error", threadName), e);
+                    errors.add(e);
+                }
+            }, threadName);
+            writers[i].start();
+        }
+
+        for (int i = 0; i < readers.length; i++) {
+            final String threadId = "reader_" + i;
+            readers[i] = new Thread(new AbstractRunnable() {
+                Closeable retentionLock = null;
+                long committedLocalCheckpointAtView;
+
+                @Override
+                public void onFailure(Exception e) {
+                    logger.error(() -> new ParameterizedMessage("--> reader [{}] had an error", threadId), e);
+                    errors.add(e);
+                    try {
+                        closeRetentionLock();
+                    } catch (IOException inner) {
+                        inner.addSuppressed(e);
+                        logger.error("unexpected error while closing view, after failure", inner);
+                    }
+                }
+
+                void closeRetentionLock() throws IOException {
+                    if (retentionLock != null) {
+                        retentionLock.close();
+                    }
+                }
+
+                void acquireRetentionLock() throws IOException {
+                    closeRetentionLock();
+                    retentionLock = translog.acquireRetentionLock();
+                    // captures the last committed checkpoint, while holding the view, simulating
+                    // recovery logic which captures a view and gets a lucene commit
+                    committedLocalCheckpointAtView = lastCommittedLocalCheckpoint.get();
+                    logger.info("--> [{}] min gen after acquiring lock [{}]", threadId, translog.getMinFileGeneration());
+                }
+
+                @Override
+                protected void doRun() throws Exception {
+                    barrier.await();
+                    int iter = 0;
+                    while (idGenerator.get() < maxOps) {
+                        if (iter++ % 10 == 0) {
+                            acquireRetentionLock();
+                        }
+
+                        // captures al views that are written since the view was created (with a small caveat see bellow)
+                        // these are what we expect the snapshot to return (and potentially some more).
+                        Set<Translog.Operation> expectedOps = new HashSet<>(writtenOps.keySet());
+                        expectedOps.removeIf(op -> op.seqNo() <= committedLocalCheckpointAtView);
+                        try (Translog.Snapshot snapshot = translog.newSnapshot(committedLocalCheckpointAtView + 1L, Long.MAX_VALUE)) {
+                            Translog.Operation op;
+                            while ((op = snapshot.next()) != null) {
+                                expectedOps.remove(op);
+                            }
+                        }
+                        if (expectedOps.isEmpty() == false) {
+                            StringBuilder missed = new StringBuilder("missed ").append(expectedOps.size())
+                                .append(" operations from [")
+                                .append(committedLocalCheckpointAtView + 1L)
+                                .append("]");
+                            boolean failed = false;
+                            for (Translog.Operation expectedOp : expectedOps) {
+                                final Translog.Location loc = writtenOps.get(expectedOp);
+                                failed = true;
+                                missed.append("\n --> [").append(expectedOp).append("] written at ").append(loc);
+                            }
+                            if (failed) {
+                                fail(missed.toString());
+                            }
+                        }
+                        // slow down things a bit and spread out testing..
+                        synchronized (signalReaderSomeDataWasIndexed) {
+                            if (idGenerator.get() < maxOps) {
+                                signalReaderSomeDataWasIndexed.wait();
+                            }
+                        }
+                    }
+                    closeRetentionLock();
+                    logger.info("--> [{}] done. tested [{}] snapshots", threadId, iter);
+                }
+            }, threadId);
+            readers[i].start();
+        }
+
+        barrier.await();
+        logger.debug("--> waiting for threads to stop");
+        for (Thread thread : writers) {
+            thread.join();
+        }
+        logger.debug("--> waiting for readers to stop");
+        // force stopping, if all writers crashed
+        synchronized (signalReaderSomeDataWasIndexed) {
+            idGenerator.set(Long.MAX_VALUE);
+            signalReaderSomeDataWasIndexed.notifyAll();
+        }
+        for (Thread thread : readers) {
+            thread.join();
+        }
+        if (errors.size() > 0) {
+            Throwable e = errors.get(0);
+            for (Throwable suppress : errors.subList(1, errors.size())) {
+                e.addSuppressed(suppress);
+            }
+            throw e;
+        }
+        logger.info("--> test done. total ops written [{}]", writtenOps.size());
+    }
+
+    public void testSyncUpTo() throws IOException {
+        int translogOperations = randomIntBetween(10, 100);
+        int count = 0;
+        for (int op = 0; op < translogOperations; op++) {
+            int seqNo = ++count;
+            final Translog.Location location = translog.add(
+                new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
+            );
+            if (randomBoolean()) {
+                assertTrue("at least one operation pending", translog.syncNeeded());
+                assertTrue("this operation has not been synced", translog.ensureSynced(location));
+                // we are the last location so everything should be synced
+                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
+                seqNo = ++count;
+                translog.add(
+                    new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
+                );
+                assertTrue("one pending operation", translog.syncNeeded());
+                assertFalse("this op has been synced before", translog.ensureSynced(location)); // not syncing now
+                assertTrue("we only synced a previous operation yet", translog.syncNeeded());
+            }
+            if (rarely()) {
+                translog.rollGeneration();
+                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(location)); // not syncing now
+                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
+            }
+
+            if (randomBoolean()) {
+                translog.sync();
+                assertFalse("translog has been synced already", translog.ensureSynced(location));
+                RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+                assertUploadStatsNoFailures(statsTracker);
+                assertDownloadStatsNoDownloads(statsTracker);
+            }
+        }
+    }
+
+    public void testSyncUpLocationFailure() throws IOException {
+        int translogOperations = randomIntBetween(1, 20);
+        int count = 0;
+        fail.failAlways();
+        ArrayList<Translog.Location> locations = new ArrayList<>();
+        boolean shouldFailAlways = randomBoolean();
+        for (int op = 0; op < translogOperations; op++) {
+            int seqNo = ++count;
+            final Translog.Location location = translog.add(
+                new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
+            );
+            if (shouldFailAlways) {
+                fail.failAlways();
+                try {
+                    translog.ensureSynced(location);
+                    fail("io exception expected");
+                } catch (IOException e) {
+                    assertTrue("at least one operation pending", translog.syncNeeded());
+                }
+            } else {
+                fail.failNever();
+                translog.ensureSynced(location);
+                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
+            }
+            locations.add(location);
+
+        }
+        // clean up
+        fail.failNever();
+
+        // writes should get synced up now
+        translog.sync();
+        assertFalse(translog.syncNeeded());
+        for (Translog.Location location : locations) {
+            assertFalse("all of the locations should be synced: " + location, translog.ensureSynced(location));
+        }
+
+        RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+        assertTrue(statsTracker.getUploadBytesStarted() > 0);
+        assertTrue(statsTracker.getTotalUploadsStarted() > 0);
+
+        if (shouldFailAlways) {
+            assertTrue(statsTracker.getTotalUploadsFailed() > 0);
+        } else {
+            assertEquals(0, statsTracker.getTotalUploadsFailed());
+        }
+
+        assertTrue(statsTracker.getTotalUploadsSucceeded() > 0);
+        assertTrue(statsTracker.getLastSuccessfulUploadTimestamp() > 0);
+        assertDownloadStatsNoDownloads(statsTracker);
+    }
+
+    public void testSyncUpAlwaysFailure() throws IOException {
+        int translogOperations = randomIntBetween(1, 20);
+        int count = 0;
+        fail.failAlways();
+        for (int op = 0; op < translogOperations; op++) {
+            translog.add(
+                new Translog.Index(String.valueOf(op), count, primaryTerm.get(), Integer.toString(count).getBytes(StandardCharsets.UTF_8))
+            );
+            try {
+                translog.sync();
+                fail("io exception expected");
+            } catch (IOException e) {
+                assertTrue("at least one operation pending", translog.syncNeeded());
+            }
+        }
+        assertTrue(translog.isOpen());
+        fail.failNever();
+        translog.sync();
+    }
+
+    public void testSyncUpToStream() throws IOException {
+        int iters = randomIntBetween(5, 10);
+        for (int i = 0; i < iters; i++) {
+            int translogOperations = randomIntBetween(10, 100);
+            int count = 0;
+            ArrayList<Translog.Location> locations = new ArrayList<>();
+            for (int op = 0; op < translogOperations; op++) {
+                if (rarely()) {
+                    translog.rollGeneration();
+                }
+                final Translog.Location location = translog.add(
+                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
+                );
+                locations.add(location);
+            }
+            Collections.shuffle(locations, random());
+            if (randomBoolean()) {
+                assertTrue("at least one operation pending", translog.syncNeeded());
+                assertTrue("this operation has not been synced", translog.ensureSynced(locations.stream()));
+                // we are the last location so everything should be synced
+                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
+            } else if (rarely()) {
+                translog.rollGeneration();
+                // not syncing now
+                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(locations.stream()));
+                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
+            } else {
+                translog.sync();
+                assertFalse("translog has been synced already", translog.ensureSynced(locations.stream()));
+            }
+
+            RemoteTranslogTransferTracker statsTracker = translog.getRemoteTranslogTracker();
+            assertUploadStatsNoFailures(statsTracker);
+            assertDownloadStatsNoDownloads(statsTracker);
+
+            for (Translog.Location location : locations) {
+                assertFalse("all of the locations should be synced: " + location, translog.ensureSynced(location));
+            }
+        }
+    }
+
+    public void testLocationComparison() throws IOException {
+        List<Translog.Location> locations = new ArrayList<>();
+        int translogOperations = randomIntBetween(10, 100);
+        int count = 0;
+        for (int op = 0; op < translogOperations; op++) {
+            locations.add(
+                translog.add(
+                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
+                )
+            );
+            if (randomBoolean()) {
+                translog.ensureSynced(locations.get(op));
+            }
+            if (rarely() && translogOperations > op + 1) {
+                translog.rollGeneration();
+            }
+        }
+        Collections.shuffle(locations, random());
+        Translog.Location max = locations.get(0);
+        for (Translog.Location location : locations) {
+            max = max(max, location);
+        }
+
+        try (Translog.Snapshot snap = new TestTranslog.SortedSnapshot(translog.newSnapshot())) {
+            Translog.Operation next;
+            Translog.Operation maxOp = null;
+            while ((next = snap.next()) != null) {
+                maxOp = next;
+            }
+            assertNotNull(maxOp);
+            assertEquals(maxOp.getSource().source.utf8ToString(), Integer.toString(count));
+        }
+    }
+
+    public static Translog.Location max(Translog.Location a, Translog.Location b) {
+        if (a.compareTo(b) > 0) {
+            return a;
+        }
+        return b;
+    }
+
+    public void testTranslogWriter() throws IOException {
+        final TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1);
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        persistedSeqNoConsumer.set(persistedSeqNos::add);
+        final int numOps = scaledRandomIntBetween(8, 250000);
+        final Set<Long> seenSeqNos = new HashSet<>();
+        boolean opsHaveValidSequenceNumbers = randomBoolean();
+        for (int i = 0; i < numOps; i++) {
+            byte[] bytes = new byte[4];
+            DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+            out.writeInt(i);
+            long seqNo;
+            do {
+                seqNo = opsHaveValidSequenceNumbers ? randomNonNegativeLong() : SequenceNumbers.UNASSIGNED_SEQ_NO;
+                opsHaveValidSequenceNumbers = opsHaveValidSequenceNumbers || !rarely();
+            } while (seenSeqNos.contains(seqNo));
+            if (seqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
+                seenSeqNos.add(seqNo);
+            }
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), seqNo);
+        }
+        assertThat(persistedSeqNos, empty());
+        writer.sync();
+        persistedSeqNos.remove(SequenceNumbers.UNASSIGNED_SEQ_NO);
+        assertEquals(seenSeqNos, persistedSeqNos);
+
+        final BaseTranslogReader reader = randomBoolean()
+            ? writer
+            : translog.openReader(writer.path(), Checkpoint.read(translog.location().resolve(Translog.CHECKPOINT_FILE_NAME)));
+        for (int i = 0; i < numOps; i++) {
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
+            buffer.flip();
+            final int value = buffer.getInt();
+            assertEquals(i, value);
+        }
+        final long minSeqNo = seenSeqNos.stream().min(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
+        final long maxSeqNo = seenSeqNos.stream().max(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
+        assertThat(reader.getCheckpoint().minSeqNo, equalTo(minSeqNo));
+        assertThat(reader.getCheckpoint().maxSeqNo, equalTo(maxSeqNo));
+
+        byte[] bytes = new byte[4];
+        DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+        out.writeInt(2048);
+        writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
+
+        if (reader instanceof TranslogReader) {
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            try {
+                reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * numOps);
+                fail("read past EOF?");
+            } catch (EOFException ex) {
+                // expected
+            }
+            ((TranslogReader) reader).close();
+        } else {
+            // live reader!
+            ByteBuffer buffer = ByteBuffer.allocate(4);
+            final long pos = reader.getFirstOperationOffset() + 4 * numOps;
+            reader.readBytes(buffer, pos);
+            buffer.flip();
+            final int value = buffer.getInt();
+            assertEquals(2048, value);
+        }
+        IOUtils.close(writer);
+    }
+
+    public void testTranslogWriterCanFlushInAddOrReadCall() throws IOException {
+        Path tempDir = createTempDir();
+        final TranslogConfig temp = getTranslogConfig(tempDir);
+        final TranslogConfig config = new TranslogConfig(
+            temp.getShardId(),
+            temp.getTranslogPath(),
+            temp.getIndexSettings(),
+            temp.getBigArrays(),
+            new ByteSizeValue(1, ByteSizeUnit.KB),
+            ""
+        );
+
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        final AtomicInteger writeCalls = new AtomicInteger();
+
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel delegate = FileChannel.open(file, openOption);
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+
+                final FileChannel channel;
+                if (isCkpFile) {
+                    channel = delegate;
+                } else {
+                    channel = new FilterFileChannel(delegate) {
+
+                        @Override
+                        public int write(ByteBuffer src) throws IOException {
+                            writeCalls.incrementAndGet();
+                            return super.write(src);
+                        }
+                    };
+                }
+                success = true;
+                return channel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(delegate);
+                }
+            }
+        };
+
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+
+        try (
+            Translog translog = new RemoteFsTranslog(
+                config,
+                translogUUID,
+                new DefaultTranslogDeletionPolicy(-1, -1, 0),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                persistedSeqNos::add,
+                repository,
+                threadPool,
+                () -> Boolean.TRUE,
+                new RemoteTranslogTransferTracker(shardId, 10)
+            ) {
+                @Override
+                ChannelFactory getChannelFactory() {
+                    return channelFactory;
+                }
+            }
+        ) {
+            TranslogWriter writer = translog.getCurrent();
+            int initialWriteCalls = writeCalls.get();
+            byte[] bytes = new byte[256];
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 3);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 4);
+            assertThat(persistedSeqNos, empty());
+            assertEquals(initialWriteCalls, writeCalls.get());
+
+            if (randomBoolean()) {
+                // Since the buffer is full, this will flush before performing the add.
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
+                assertThat(persistedSeqNos, empty());
+                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
+            } else {
+                // Will flush on read
+                writer.readBytes(ByteBuffer.allocate(256), 0);
+                assertThat(persistedSeqNos, empty());
+                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
+
+                // Add after we the read flushed the buffer
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
+            }
+
+            writer.sync();
+
+            // Sequence numbers are marked as persisted after sync
+            assertThat(persistedSeqNos, contains(1L, 2L, 3L, 4L, 5L));
+        }
+    }
+
+    public void testTranslogWriterFsyncDisabledInRemoteFsTranslog() throws IOException {
+        Path tempDir = createTempDir();
+        final TranslogConfig temp = getTranslogConfig(tempDir);
+        final TranslogConfig config = new TranslogConfig(
+            temp.getShardId(),
+            temp.getTranslogPath(),
+            temp.getIndexSettings(),
+            temp.getBigArrays(),
+            new ByteSizeValue(1, ByteSizeUnit.KB),
+            ""
+        );
+
+        final Set<Long> persistedSeqNos = new HashSet<>();
+        final AtomicInteger translogFsyncCalls = new AtomicInteger();
+        final AtomicInteger checkpointFsyncCalls = new AtomicInteger();
+
+        final ChannelFactory channelFactory = (file, openOption) -> {
+            FileChannel delegate = FileChannel.open(file, openOption);
+            boolean success = false;
+            try {
+                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
+                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
+
+                final FileChannel channel;
+                if (isCkpFile) {
+                    channel = new FilterFileChannel(delegate) {
+                        @Override
+                        public void force(boolean metaData) throws IOException {
+                            checkpointFsyncCalls.incrementAndGet();
+                        }
+                    };
+                } else {
+                    channel = new FilterFileChannel(delegate) {
+
+                        @Override
+                        public void force(boolean metaData) throws IOException {
+                            translogFsyncCalls.incrementAndGet();
+                        }
+                    };
+                }
+                success = true;
+                return channel;
+            } finally {
+                if (success == false) {
+                    IOUtils.closeWhileHandlingException(delegate);
+                }
+            }
+        };
+
+        String translogUUID = Translog.createEmptyTranslog(
+            config.getTranslogPath(),
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            channelFactory,
+            primaryTerm.get()
+        );
+
+        try (
+            Translog translog = new RemoteFsTranslog(
+                config,
+                translogUUID,
+                new DefaultTranslogDeletionPolicy(-1, -1, 0),
+                () -> SequenceNumbers.NO_OPS_PERFORMED,
+                primaryTerm::get,
+                persistedSeqNos::add,
+                repository,
+                threadPool,
+                () -> Boolean.TRUE,
+                new RemoteTranslogTransferTracker(shardId, 10)
+            ) {
+                @Override
+                ChannelFactory getChannelFactory() {
+                    return channelFactory;
+                }
+            }
+        ) {
+            TranslogWriter writer = translog.getCurrent();
+            byte[] bytes = new byte[256];
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 3);
+            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 4);
+            writer.sync();
+            // Fsync is still enabled during empty translog creation.
+            assertEquals(2, checkpointFsyncCalls.get());
+            assertEquals(1, translogFsyncCalls.get());
+            // Sequence numbers are marked as persisted after sync
+            assertThat(persistedSeqNos, contains(1L, 2L, 3L, 4L));
+        }
+    }
+
+    public void testCloseIntoReader() throws IOException {
+        try (TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1)) {
+            final int numOps = randomIntBetween(8, 128);
+            for (int i = 0; i < numOps; i++) {
+                final byte[] bytes = new byte[4];
+                final DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
+                out.writeInt(i);
+                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
+            }
+            writer.sync();
+            final Checkpoint writerCheckpoint = writer.getCheckpoint();
+            TranslogReader reader = writer.closeIntoReader();
+            try {
+                if (randomBoolean()) {
+                    reader.close();
+                    reader = translog.openReader(reader.path(), writerCheckpoint);
+                }
+                for (int i = 0; i < numOps; i++) {
+                    final ByteBuffer buffer = ByteBuffer.allocate(4);
+                    reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
+                    buffer.flip();
+                    final int value = buffer.getInt();
+                    assertEquals(i, value);
+                }
+                final Checkpoint readerCheckpoint = reader.getCheckpoint();
+                assertThat(readerCheckpoint, equalTo(writerCheckpoint));
+            } finally {
+                IOUtils.close(reader);
+            }
+        }
+    }
+
+    public void testDownloadWithRetries() throws IOException {
+        long generation = 1, primaryTerm = 1;
+        Path location = createTempDir();
+        TranslogTransferMetadata translogTransferMetadata = new TranslogTransferMetadata(primaryTerm, generation, generation, 1);
+        Map<String, String> generationToPrimaryTermMapper = new HashMap<>();
+        generationToPrimaryTermMapper.put(String.valueOf(generation), String.valueOf(primaryTerm));
+        translogTransferMetadata.setGenerationToPrimaryTermMapper(generationToPrimaryTermMapper);
+
+        TranslogTransferManager mockTransfer = mock(TranslogTransferManager.class);
+        RemoteTranslogTransferTracker remoteTranslogTransferTracker = mock(RemoteTranslogTransferTracker.class);
+        when(mockTransfer.readMetadata()).thenReturn(translogTransferMetadata);
+        when(mockTransfer.getRemoteTranslogTransferTracker()).thenReturn(remoteTranslogTransferTracker);
+
+        // Always File not found
+        when(mockTransfer.downloadTranslog(any(), any(), any())).thenThrow(new NoSuchFileException("File not found"));
+        TranslogTransferManager finalMockTransfer = mockTransfer;
+        assertThrows(NoSuchFileException.class, () -> RemoteFsTranslog.download(finalMockTransfer, location, logger));
+
+        // File not found in first attempt . File found in second attempt.
+        mockTransfer = mock(TranslogTransferManager.class);
+        when(mockTransfer.readMetadata()).thenReturn(translogTransferMetadata);
+        when(mockTransfer.getRemoteTranslogTransferTracker()).thenReturn(remoteTranslogTransferTracker);
+        String msg = "File not found";
+        Exception toThrow = randomBoolean() ? new NoSuchFileException(msg) : new FileNotFoundException(msg);
+        when(mockTransfer.downloadTranslog(any(), any(), any())).thenThrow(toThrow).thenReturn(true);
+
+        AtomicLong downloadCounter = new AtomicLong();
+        doAnswer(invocation -> {
+            if (downloadCounter.incrementAndGet() <= 1) {
+                throw new NoSuchFileException("File not found");
+            } else if (downloadCounter.get() == 2) {
+                Files.createFile(location.resolve(Translog.getCommitCheckpointFileName(generation)));
+            }
+            return true;
+        }).when(mockTransfer).downloadTranslog(any(), any(), any());
+
+        // no exception thrown
+        RemoteFsTranslog.download(mockTransfer, location, logger);
+    }
+
+    public class ThrowingBlobRepository extends FsRepository {
+        private final Environment environment;
+
+        private TestTranslog.FailSwitch fail;
+
+        public ThrowingBlobRepository(
+            RepositoryMetadata metadata,
+            Environment environment,
+            NamedXContentRegistry namedXContentRegistry,
+            ClusterService clusterService,
+            RecoverySettings recoverySettings,
+            TestTranslog.FailSwitch fail
+        ) {
+            super(metadata, environment, namedXContentRegistry, clusterService, recoverySettings);
+            this.environment = environment;
+            this.fail = fail;
+        }
+
+        protected BlobStore createBlobStore() throws Exception {
+            final String location = REPOSITORIES_LOCATION_SETTING.get(getMetadata().settings());
+            final Path locationFile = environment.resolveRepoFile(location);
+            return new ThrowingBlobStore(bufferSize, locationFile, isReadOnly(), fail);
+        }
+    }
+
+    private class ThrowingBlobStore extends FsBlobStore {
+
+        private TestTranslog.FailSwitch fail;
+
+        public ThrowingBlobStore(int bufferSizeInBytes, Path path, boolean readonly, TestTranslog.FailSwitch fail) throws IOException {
+            super(bufferSizeInBytes, path, readonly);
+            this.fail = fail;
+        }
+
+        @Override
+        public BlobContainer blobContainer(BlobPath path) {
+            try {
+                return new ThrowingBlobContainer(this, path, buildAndCreate(path), fail);
+            } catch (IOException ex) {
+                throw new OpenSearchException("failed to create blob container", ex);
+            }
+        }
+    }
+
+    private class ThrowingBlobContainer extends FsBlobContainer {
+
+        private TestTranslog.FailSwitch fail;
+
+        public ThrowingBlobContainer(FsBlobStore blobStore, BlobPath blobPath, Path path, TestTranslog.FailSwitch fail) {
+            super(blobStore, blobPath, path);
+            this.fail = fail;
+        }
+
+        public void writeBlobAtomic(final String blobName, final InputStream inputStream, final long blobSize, boolean failIfAlreadyExists)
+            throws IOException {
+            if (fail.fail()) {
+                throw new IOException("blob container throwing error");
+            }
+            super.writeBlobAtomic(blobName, inputStream, blobSize, failIfAlreadyExists);
+        }
+    }
+
+    class TranslogThread extends Thread {
+        private final CountDownLatch downLatch;
+        private final int opsPerThread;
+        private final int threadId;
+        private final Collection<TestTranslog.LocationOperation> writtenOperations;
+        private final Exception[] threadExceptions;
+        private final Translog translog;
+        private final AtomicLong seqNoGenerator;
+
+        TranslogThread(
+            Translog translog,
+            CountDownLatch downLatch,
+            int opsPerThread,
+            int threadId,
+            Collection<TestTranslog.LocationOperation> writtenOperations,
+            AtomicLong seqNoGenerator,
+            Exception[] threadExceptions
+        ) {
+            this.translog = translog;
+            this.downLatch = downLatch;
+            this.opsPerThread = opsPerThread;
+            this.threadId = threadId;
+            this.writtenOperations = writtenOperations;
+            this.seqNoGenerator = seqNoGenerator;
+            this.threadExceptions = threadExceptions;
+        }
+
+        @Override
+        public void run() {
+            try {
+                downLatch.await();
+                for (int opCount = 0; opCount < opsPerThread; opCount++) {
+                    Translog.Operation op;
+                    final Translog.Operation.Type type = randomFrom(Translog.Operation.Type.values());
+                    switch (type) {
+                        case CREATE:
+                        case INDEX:
+                            op = new Translog.Index(
+                                threadId + "_" + opCount,
+                                seqNoGenerator.getAndIncrement(),
+                                primaryTerm.get(),
+                                randomUnicodeOfLengthBetween(1, 20 * 1024).getBytes("UTF-8")
+                            );
+                            break;
+                        case DELETE:
+                            op = new Translog.Delete(
+                                threadId + "_" + opCount,
+                                seqNoGenerator.getAndIncrement(),
+                                primaryTerm.get(),
+                                1 + randomInt(100000)
+                            );
+                            break;
+                        case NO_OP:
+                            op = new Translog.NoOp(seqNoGenerator.getAndIncrement(), primaryTerm.get(), randomAlphaOfLength(16));
+                            break;
+                        default:
+                            throw new AssertionError("unsupported operation type [" + type + "]");
+                    }
+
+                    Translog.Location loc = add(op);
+                    writtenOperations.add(new TestTranslog.LocationOperation(op, loc));
+                    if (rarely()) { // lets verify we can concurrently read this
+                        assertEquals(op, translog.readOperation(loc));
+                    }
+                    afterAdd();
+                }
+            } catch (Exception t) {
+                threadExceptions[threadId] = t;
+            }
+        }
+
+        protected Translog.Location add(Translog.Operation op) throws IOException {
+            Translog.Location location = translog.add(op);
+            if (randomBoolean()) {
+                translog.ensureSynced(location);
+            }
+            return location;
+        }
+
+        protected void afterAdd() {}
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/RemoteTranslogStatsTests.java b/server/src/test/java/org/opensearch/index/translog/RemoteTranslogStatsTests.java
new file mode 100644
index 0000000000000..aa390cdba1275
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/RemoteTranslogStatsTests.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+
+public class RemoteTranslogStatsTests extends OpenSearchTestCase {
+    RemoteTranslogTransferTracker.Stats transferTrackerStats;
+    RemoteTranslogStats remoteTranslogStats;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        transferTrackerStats = getRandomTransferTrackerStats();
+        remoteTranslogStats = new RemoteTranslogStats(transferTrackerStats);
+    }
+
+    public void testRemoteTranslogStatsCreationFromTransferTrackerStats() {
+        assertEquals(transferTrackerStats.totalUploadsStarted, remoteTranslogStats.getTotalUploadsStarted());
+        assertEquals(transferTrackerStats.totalUploadsSucceeded, remoteTranslogStats.getTotalUploadsSucceeded());
+        assertEquals(transferTrackerStats.totalUploadsFailed, remoteTranslogStats.getTotalUploadsFailed());
+        assertEquals(transferTrackerStats.uploadBytesStarted, remoteTranslogStats.getUploadBytesStarted());
+        assertEquals(transferTrackerStats.uploadBytesSucceeded, remoteTranslogStats.getUploadBytesSucceeded());
+        assertEquals(transferTrackerStats.uploadBytesFailed, remoteTranslogStats.getUploadBytesFailed());
+    }
+
+    public void testRemoteTranslogStatsSerialization() throws IOException {
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            remoteTranslogStats.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                RemoteTranslogStats remoteTranslogStatsFromStream = new RemoteTranslogStats(in);
+                assertEquals(remoteTranslogStats, remoteTranslogStatsFromStream);
+            }
+        }
+    }
+
+    public void testAdd() {
+        RemoteTranslogTransferTracker.Stats otherTransferTrackerStats = getRandomTransferTrackerStats();
+        RemoteTranslogStats otherRemoteTranslogStats = new RemoteTranslogStats(otherTransferTrackerStats);
+
+        otherRemoteTranslogStats.add(remoteTranslogStats);
+
+        assertEquals(
+            otherRemoteTranslogStats.getTotalUploadsStarted(),
+            otherTransferTrackerStats.totalUploadsStarted + remoteTranslogStats.getTotalUploadsStarted()
+        );
+        assertEquals(
+            otherRemoteTranslogStats.getTotalUploadsSucceeded(),
+            otherTransferTrackerStats.totalUploadsSucceeded + remoteTranslogStats.getTotalUploadsSucceeded()
+        );
+        assertEquals(
+            otherRemoteTranslogStats.getTotalUploadsFailed(),
+            otherTransferTrackerStats.totalUploadsFailed + remoteTranslogStats.getTotalUploadsFailed()
+        );
+        assertEquals(
+            otherRemoteTranslogStats.getUploadBytesStarted(),
+            otherTransferTrackerStats.uploadBytesStarted + remoteTranslogStats.getUploadBytesStarted()
+        );
+        assertEquals(
+            otherRemoteTranslogStats.getUploadBytesSucceeded(),
+            otherTransferTrackerStats.uploadBytesSucceeded + remoteTranslogStats.getUploadBytesSucceeded()
+        );
+        assertEquals(
+            otherRemoteTranslogStats.getUploadBytesFailed(),
+            otherTransferTrackerStats.uploadBytesFailed + remoteTranslogStats.getUploadBytesFailed()
+        );
+    }
+
+    private static RemoteTranslogTransferTracker.Stats getRandomTransferTrackerStats() {
+        return new RemoteTranslogTransferTracker.Stats(
+            new ShardId("test-idx", "test-idx", randomIntBetween(1, 10)),
+            0L,
+            randomLongBetween(100, 500),
+            randomLongBetween(50, 100),
+            randomLongBetween(100, 200),
+            randomLongBetween(10000, 50000),
+            randomLongBetween(5000, 10000),
+            randomLongBetween(10000, 20000),
+            0L,
+            0D,
+            0D,
+            0D,
+            0L,
+            0L,
+            0L,
+            0L,
+            0D,
+            0D,
+            0D
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/SnapshotMatchers.java b/server/src/test/java/org/opensearch/index/translog/SnapshotMatchers.java
index 0277e420f74ed..c9de270cf7568 100644
--- a/server/src/test/java/org/opensearch/index/translog/SnapshotMatchers.java
+++ b/server/src/test/java/org/opensearch/index/translog/SnapshotMatchers.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.index.translog;
 
-import com.carrotsearch.hppc.LongHashSet;
-import com.carrotsearch.hppc.LongSet;
 import org.opensearch.OpenSearchException;
 import org.hamcrest.Description;
 import org.hamcrest.Matcher;
@@ -42,7 +40,9 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 public final class SnapshotMatchers {
@@ -217,7 +217,7 @@ static class ContainingSeqNoRangeMatcher extends TypeSafeMatcher<Translog.Snapsh
         @Override
         protected boolean matchesSafely(Translog.Snapshot snapshot) {
             try {
-                final LongSet seqNoList = new LongHashSet();
+                final Set<Long> seqNoList = new HashSet<>();
                 Translog.Operation op;
                 while ((op = snapshot.next()) != null) {
                     seqNoList.add(op.seqNo());
diff --git a/server/src/test/java/org/opensearch/index/translog/TestTranslog.java b/server/src/test/java/org/opensearch/index/translog/TestTranslog.java
index 4e9d56aeb9573..fd4be1d7a8635 100644
--- a/server/src/test/java/org/opensearch/index/translog/TestTranslog.java
+++ b/server/src/test/java/org/opensearch/index/translog/TestTranslog.java
@@ -34,10 +34,12 @@
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.tests.util.LuceneTestCase;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -283,4 +285,88 @@ static boolean isTranslogHeaderVersionFlipped(Path corruptedFile, FileChannel ch
             return false;
         }
     }
+
+    static class LocationOperation implements Comparable<LocationOperation> {
+        final Translog.Operation operation;
+        final Translog.Location location;
+
+        LocationOperation(Translog.Operation operation, Translog.Location location) {
+            this.operation = operation;
+            this.location = location;
+        }
+
+        @Override
+        public int compareTo(LocationOperation o) {
+            return location.compareTo(o.location);
+        }
+    }
+
+    static class FailSwitch {
+        private volatile int failRate;
+        private volatile boolean onceFailedFailAlways = false;
+
+        public boolean fail() {
+            final int rnd = OpenSearchTestCase.randomIntBetween(1, 100);
+            boolean fail = rnd <= failRate;
+            if (fail && onceFailedFailAlways) {
+                failAlways();
+            }
+            return fail;
+        }
+
+        public void failNever() {
+            failRate = 0;
+        }
+
+        public void failAlways() {
+            failRate = 100;
+        }
+
+        public void failRandomly() {
+            failRate = OpenSearchTestCase.randomIntBetween(1, 100);
+        }
+
+        public void failRate(int rate) {
+            failRate = rate;
+        }
+
+        public void onceFailedFailAlways() {
+            onceFailedFailAlways = true;
+        }
+    }
+
+    static class SortedSnapshot implements Translog.Snapshot {
+        private final Translog.Snapshot snapshot;
+        private List<Translog.Operation> operations = null;
+
+        SortedSnapshot(Translog.Snapshot snapshot) {
+            this.snapshot = snapshot;
+        }
+
+        @Override
+        public int totalOperations() {
+            return snapshot.totalOperations();
+        }
+
+        @Override
+        public Translog.Operation next() throws IOException {
+            if (operations == null) {
+                operations = new ArrayList<>();
+                Translog.Operation op;
+                while ((op = snapshot.next()) != null) {
+                    operations.add(op);
+                }
+                operations.sort(Comparator.comparing(Translog.Operation::seqNo));
+            }
+            if (operations.isEmpty()) {
+                return null;
+            }
+            return operations.remove(0);
+        }
+
+        @Override
+        public void close() throws IOException {
+            snapshot.close();
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/index/translog/TranslogDeletionPolicyTests.java b/server/src/test/java/org/opensearch/index/translog/TranslogDeletionPolicyTests.java
index e5a41fdc15da1..91d51ffd105f0 100644
--- a/server/src/test/java/org/opensearch/index/translog/TranslogDeletionPolicyTests.java
+++ b/server/src/test/java/org/opensearch/index/translog/TranslogDeletionPolicyTests.java
@@ -38,10 +38,9 @@
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.Mockito;
 
 import java.io.IOException;
 import java.nio.channels.FileChannel;
@@ -50,6 +49,8 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import org.mockito.Mockito;
+
 import static java.lang.Math.min;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -256,7 +257,8 @@ private Tuple<List<TranslogReader>, TranslogWriter> createReadersAndWriter(final
                 randomNonNegativeLong(),
                 new TragicExceptionHolder(),
                 seqNo -> {},
-                BigArrays.NON_RECYCLING_INSTANCE
+                BigArrays.NON_RECYCLING_INSTANCE,
+                null
             );
             writer = Mockito.spy(writer);
             Mockito.doReturn(now - (numberOfReaders - gen + 1) * 1000).when(writer).getLastModifiedTime();
diff --git a/server/src/test/java/org/opensearch/index/translog/TranslogHeaderTests.java b/server/src/test/java/org/opensearch/index/translog/TranslogHeaderTests.java
index 3569d596a5569..a5d6ee7a06e23 100644
--- a/server/src/test/java/org/opensearch/index/translog/TranslogHeaderTests.java
+++ b/server/src/test/java/org/opensearch/index/translog/TranslogHeaderTests.java
@@ -36,7 +36,7 @@
 import org.apache.lucene.store.OutputStreamDataOutput;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -63,7 +63,7 @@ public void testCurrentHeaderVersion() throws Exception {
         final long generation = randomNonNegativeLong();
         final Path translogFile = createTempDir().resolve(Translog.getFilename(generation));
         try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE)) {
-            outHeader.write(channel);
+            outHeader.write(channel, true);
             assertThat(outHeader.sizeInBytes(), equalTo((int) channel.position()));
         }
         try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
@@ -132,6 +132,49 @@ public void testHeaderWithoutPrimaryTerm() throws Exception {
         });
     }
 
+    public void testCurrentHeaderVersionWithoutUUIDComparison() throws Exception {
+        final String translogUUID = UUIDs.randomBase64UUID();
+        final TranslogHeader outHeader = new TranslogHeader(translogUUID, randomNonNegativeLong());
+        final long generation = randomNonNegativeLong();
+        final Path translogFile = createTempDir().resolve(Translog.getFilename(generation));
+        try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE)) {
+            outHeader.write(channel, true);
+            assertThat(outHeader.sizeInBytes(), equalTo((int) channel.position()));
+        }
+        try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
+            final TranslogHeader inHeader = TranslogHeader.read(translogFile, channel);
+            assertThat(inHeader.getTranslogUUID(), equalTo(translogUUID));
+            assertThat(inHeader.getPrimaryTerm(), equalTo(outHeader.getPrimaryTerm()));
+            assertThat(inHeader.sizeInBytes(), equalTo((int) channel.position()));
+        }
+
+        TestTranslog.corruptFile(logger, random(), translogFile, false);
+        final TranslogCorruptedException corruption = expectThrows(TranslogCorruptedException.class, () -> {
+            try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
+                final TranslogHeader translogHeader = TranslogHeader.read(translogFile, channel);
+                assertThat(
+                    "version " + TranslogHeader.VERSION_CHECKPOINTS + " translog",
+                    translogHeader.getPrimaryTerm(),
+                    equalTo(SequenceNumbers.UNASSIGNED_PRIMARY_TERM)
+                );
+                throw new TranslogCorruptedException(translogFile.toString(), "adjusted translog version");
+            } catch (IllegalStateException e) {
+                // corruption corrupted the version byte making this look like a v2, v1 or v0 translog
+                assertThat(
+                    "version " + TranslogHeader.VERSION_CHECKPOINTS + "-or-earlier translog",
+                    e.getMessage(),
+                    anyOf(
+                        containsString("pre-2.0 translog found"),
+                        containsString("pre-1.4 translog found"),
+                        containsString("pre-6.3 translog found")
+                    )
+                );
+                throw new TranslogCorruptedException(translogFile.toString(), "adjusted translog version", e);
+            }
+        });
+        assertThat(corruption.getMessage(), not(containsString("this translog file belongs to a different translog")));
+    }
+
     static void writeHeaderWithoutTerm(FileChannel channel, String translogUUID) throws IOException {
         final OutputStreamStreamOutput out = new OutputStreamStreamOutput(Channels.newOutputStream(channel));
         CodecUtil.writeHeader(new OutputStreamDataOutput(out), TranslogHeader.TRANSLOG_CODEC, TranslogHeader.VERSION_CHECKPOINTS);
@@ -165,7 +208,7 @@ public void testCorruptTranslogHeader() throws Exception {
         final Path translogLocation = createTempDir();
         final Path translogFile = translogLocation.resolve(Translog.getFilename(generation));
         try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE)) {
-            outHeader.write(channel);
+            outHeader.write(channel, true);
             assertThat(outHeader.sizeInBytes(), equalTo((int) channel.position()));
         }
         TestTranslog.corruptFile(logger, random(), translogFile, false);
diff --git a/server/src/test/java/org/opensearch/index/translog/TranslogManagerTestCase.java b/server/src/test/java/org/opensearch/index/translog/TranslogManagerTestCase.java
new file mode 100644
index 0000000000000..e17d2770f014a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/TranslogManagerTestCase.java
@@ -0,0 +1,217 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog;
+
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.StoredField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.AllocationId;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.EngineConfig;
+import org.opensearch.index.mapper.IdFieldMapper;
+import org.opensearch.index.mapper.Mapping;
+import org.opensearch.index.mapper.ParseContext;
+import org.opensearch.index.mapper.ParsedDocument;
+import org.opensearch.index.mapper.SeqNoFieldMapper;
+import org.opensearch.index.mapper.SourceFieldMapper;
+import org.opensearch.index.mapper.Uid;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.LongSupplier;
+
+import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
+
+public abstract class TranslogManagerTestCase extends OpenSearchTestCase {
+
+    protected final ShardId shardId = new ShardId(new Index("index", "_na_"), 0);
+    protected final AllocationId allocationId = AllocationId.newInitializing();
+    protected static final IndexSettings INDEX_SETTINGS = IndexSettingsModule.newIndexSettings("index", Settings.EMPTY);
+    private AtomicLong globalCheckpoint;
+    protected ThreadPool threadPool;
+    protected final PrimaryTermSupplier primaryTerm = new PrimaryTermSupplier(1L);
+
+    protected IndexSettings defaultSettings;
+    protected String codecName;
+    protected Path primaryTranslogDir;
+    protected String translogUUID;
+
+    protected static final BytesArray SOURCE = bytesArray("{}");
+    protected static final BytesReference B_1 = new BytesArray(new byte[] { 1 });
+
+    protected Translog createTranslog(LongSupplier primaryTermSupplier) throws IOException {
+        return createTranslog(primaryTranslogDir, primaryTermSupplier);
+    }
+
+    protected Translog createTranslog(Path translogPath, LongSupplier primaryTermSupplier) throws IOException {
+        TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, "");
+        String translogUUID = Translog.createEmptyTranslog(
+            translogPath,
+            SequenceNumbers.NO_OPS_PERFORMED,
+            shardId,
+            primaryTermSupplier.getAsLong()
+        );
+        return new LocalTranslog(
+            translogConfig,
+            translogUUID,
+            createTranslogDeletionPolicy(INDEX_SETTINGS),
+            () -> SequenceNumbers.NO_OPS_PERFORMED,
+            primaryTermSupplier,
+            seqNo -> {}
+        );
+    }
+
+    private String create(Path path) throws IOException {
+        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        return Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
+    }
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        primaryTerm.set(randomIntBetween(1, 100));
+        defaultSettings = IndexSettingsModule.newIndexSettings("test", indexSettings());
+        threadPool = new TestThreadPool(getClass().getName());
+        primaryTranslogDir = createTempDir("translog-primary");
+        translogUUID = create(primaryTranslogDir);
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        IOUtils.close(() -> terminate(threadPool));
+    }
+
+    protected Settings indexSettings() {
+        // TODO randomize more settings
+        return Settings.builder()
+            .put(IndexSettings.INDEX_GC_DELETES_SETTING.getKey(), "1h") // make sure this doesn't kick in on us
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), codecName)
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(
+                IndexSettings.MAX_REFRESH_LISTENERS_PER_SHARD.getKey(),
+                between(10, 10 * IndexSettings.MAX_REFRESH_LISTENERS_PER_SHARD.get(Settings.EMPTY))
+            )
+            .put(IndexSettings.INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING.getKey(), between(0, 1000))
+            .build();
+    }
+
+    public static final class PrimaryTermSupplier implements LongSupplier {
+        private final AtomicLong term;
+
+        PrimaryTermSupplier(long initialTerm) {
+            this.term = new AtomicLong(initialTerm);
+        }
+
+        public long get() {
+            return term.get();
+        }
+
+        public void set(long newTerm) {
+            this.term.set(newTerm);
+        }
+
+        @Override
+        public long getAsLong() {
+            return get();
+        }
+    }
+
+    protected static ParsedDocument testParsedDocument(
+        String id,
+        String routing,
+        ParseContext.Document document,
+        BytesReference source,
+        Mapping mappingUpdate
+    ) {
+        return testParsedDocument(id, routing, document, source, mappingUpdate, false);
+    }
+
+    protected static ParsedDocument testParsedDocument(
+        String id,
+        String routing,
+        ParseContext.Document document,
+        BytesReference source,
+        Mapping mappingUpdate,
+        boolean recoverySource
+    ) {
+        Field uidField = new Field("_id", Uid.encodeId(id), IdFieldMapper.Defaults.FIELD_TYPE);
+        Field versionField = new NumericDocValuesField("_version", 0);
+        SeqNoFieldMapper.SequenceIDFields seqID = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
+        document.add(uidField);
+        document.add(versionField);
+        document.add(seqID.seqNo);
+        document.add(seqID.seqNoDocValue);
+        document.add(seqID.primaryTerm);
+        BytesRef ref = source.toBytesRef();
+        if (recoverySource) {
+            document.add(new StoredField(SourceFieldMapper.RECOVERY_SOURCE_NAME, ref.bytes, ref.offset, ref.length));
+            document.add(new NumericDocValuesField(SourceFieldMapper.RECOVERY_SOURCE_NAME, 1));
+        } else {
+            document.add(new StoredField(SourceFieldMapper.NAME, ref.bytes, ref.offset, ref.length));
+        }
+        return new ParsedDocument(versionField, seqID, id, routing, List.of(document), source, MediaTypeRegistry.JSON, mappingUpdate);
+    }
+
+    protected static ParseContext.Document testDocumentWithTextField() {
+        return testDocumentWithTextField("test");
+    }
+
+    protected static ParseContext.Document testDocumentWithTextField(String value) {
+        ParseContext.Document document = testDocument();
+        document.add(new TextField("value", value, Field.Store.YES));
+        return document;
+    }
+
+    protected static ParseContext.Document testDocument() {
+        return new ParseContext.Document();
+    }
+
+    protected Engine.Index indexForDoc(ParsedDocument doc) {
+        return new Engine.Index(newUid(doc), primaryTerm.get(), doc);
+    }
+
+    public static Term newUid(String id) {
+        return new Term("_id", Uid.encodeId(id));
+    }
+
+    public static Term newUid(ParsedDocument doc) {
+        return newUid(doc.id());
+    }
+
+    protected static BytesArray bytesArray(String string) {
+        return new BytesArray(string.getBytes(Charset.defaultCharset()));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/TranslogTests.java b/server/src/test/java/org/opensearch/index/translog/TranslogTests.java
deleted file mode 100644
index 153677e00c22b..0000000000000
--- a/server/src/test/java/org/opensearch/index/translog/TranslogTests.java
+++ /dev/null
@@ -1,4088 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.index.translog;
-
-import com.carrotsearch.randomizedtesting.generators.RandomPicks;
-import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.backward_codecs.store.EndiannessReverserUtil;
-import org.apache.lucene.codecs.CodecUtil;
-import org.apache.lucene.document.Field;
-import org.apache.lucene.document.NumericDocValuesField;
-import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.IndexFormatTooOldException;
-import org.apache.lucene.index.Term;
-import org.apache.lucene.tests.mockfile.FilterFileChannel;
-import org.apache.lucene.tests.mockfile.FilterFileSystemProvider;
-import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.store.ByteArrayDataOutput;
-import org.apache.lucene.store.DataOutput;
-import org.apache.lucene.tests.store.MockDirectoryWrapper;
-import org.apache.lucene.tests.util.LineFileDocs;
-import org.apache.lucene.tests.util.LuceneTestCase;
-import org.opensearch.Assertions;
-import org.opensearch.Version;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
-import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.util.concurrent.AbstractRunnable;
-import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.util.concurrent.ReleasableLock;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.IndexSettings;
-import org.opensearch.index.VersionType;
-import org.opensearch.index.engine.Engine;
-import org.opensearch.index.engine.Engine.Operation.Origin;
-import org.opensearch.index.engine.MissingHistoryOperationsException;
-import org.opensearch.index.mapper.IdFieldMapper;
-import org.opensearch.index.mapper.ParseContext.Document;
-import org.opensearch.index.mapper.ParsedDocument;
-import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.Uid;
-import org.opensearch.index.seqno.LocalCheckpointTracker;
-import org.opensearch.index.seqno.LocalCheckpointTrackerTests;
-import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.translog.Translog.Location;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.test.IndexSettingsModule;
-import org.opensearch.test.VersionUtils;
-import org.hamcrest.Matchers;
-import org.junit.After;
-import org.junit.Before;
-
-import java.io.Closeable;
-import java.io.EOFException;
-import java.io.IOException;
-import java.nio.ByteBuffer;
-import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.CopyOption;
-import java.nio.file.FileAlreadyExistsException;
-import java.nio.file.Files;
-import java.nio.file.InvalidPathException;
-import java.nio.file.Path;
-import java.nio.file.StandardOpenOption;
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Deque;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.IdentityHashMap;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Queue;
-import java.util.Random;
-import java.util.Set;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.BrokenBarrierException;
-import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.CyclicBarrier;
-import java.util.concurrent.Phaser;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.atomic.AtomicReference;
-import java.util.function.LongConsumer;
-import java.util.function.LongSupplier;
-import java.util.stream.Collectors;
-import java.util.stream.IntStream;
-import java.util.stream.LongStream;
-import java.util.stream.Stream;
-
-import static org.opensearch.common.util.BigArrays.NON_RECYCLING_INSTANCE;
-import static org.opensearch.index.translog.SnapshotMatchers.containsOperationsInAnyOrder;
-import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
-import static org.hamcrest.CoreMatchers.hasItem;
-import static org.hamcrest.Matchers.contains;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.empty;
-import static org.hamcrest.Matchers.endsWith;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.hasToString;
-import static org.hamcrest.Matchers.in;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
-import static org.hamcrest.Matchers.not;
-import static org.hamcrest.Matchers.nullValue;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-@LuceneTestCase.SuppressFileSystems("ExtrasFS")
-public class TranslogTests extends OpenSearchTestCase {
-
-    protected final ShardId shardId = new ShardId("index", "_na_", 1);
-
-    protected Translog translog;
-    private AtomicLong globalCheckpoint;
-    protected Path translogDir;
-    // A default primary term is used by translog instances created in this test.
-    private final AtomicLong primaryTerm = new AtomicLong();
-    private final AtomicReference<LongConsumer> persistedSeqNoConsumer = new AtomicReference<>();
-    private boolean expectIntactTranslog;
-
-    @Before
-    public void expectIntactTranslogByDefault() {
-        expectIntactTranslog = true;
-    }
-
-    @Override
-    protected void afterIfSuccessful() throws Exception {
-        super.afterIfSuccessful();
-
-        if (translog.isOpen()) {
-            if (translog.currentFileGeneration() > 1) {
-                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(Long.MAX_VALUE);
-                translog.trimUnreferencedReaders();
-                assertFileDeleted(translog, translog.currentFileGeneration() - 1);
-            }
-            translog.close();
-        }
-        if (expectIntactTranslog) {
-            assertFileIsPresent(translog, translog.currentFileGeneration());
-        }
-        IOUtils.rm(translog.location()); // delete all the locations
-
-    }
-
-    private LongConsumer getPersistedSeqNoConsumer() {
-        return seqNo -> {
-            final LongConsumer consumer = persistedSeqNoConsumer.get();
-            if (consumer != null) {
-                consumer.accept(seqNo);
-            }
-        };
-    }
-
-    protected Translog createTranslog(TranslogConfig config) throws IOException {
-        String translogUUID = Translog.createEmptyTranslog(
-            config.getTranslogPath(),
-            SequenceNumbers.NO_OPS_PERFORMED,
-            shardId,
-            primaryTerm.get()
-        );
-        return new Translog(
-            config,
-            translogUUID,
-            createTranslogDeletionPolicy(config.getIndexSettings()),
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            getPersistedSeqNoConsumer()
-        );
-    }
-
-    protected Translog openTranslog(TranslogConfig config, String translogUUID) throws IOException {
-        return new Translog(
-            config,
-            translogUUID,
-            createTranslogDeletionPolicy(config.getIndexSettings()),
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            getPersistedSeqNoConsumer()
-        );
-    }
-
-    @Override
-    @Before
-    public void setUp() throws Exception {
-        super.setUp();
-        primaryTerm.set(randomLongBetween(1, Integer.MAX_VALUE));
-        // if a previous test failed we clean up things here
-        translogDir = createTempDir();
-        translog = create(translogDir);
-    }
-
-    @Override
-    @After
-    public void tearDown() throws Exception {
-        try {
-            translog.getDeletionPolicy().assertNoOpenTranslogRefs();
-            translog.close();
-        } finally {
-            super.tearDown();
-        }
-    }
-
-    private Translog create(Path path) throws IOException {
-        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        final TranslogConfig translogConfig = getTranslogConfig(path);
-        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(translogConfig.getIndexSettings());
-        final String translogUUID = Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
-        return new Translog(
-            translogConfig,
-            translogUUID,
-            deletionPolicy,
-            () -> globalCheckpoint.get(),
-            primaryTerm::get,
-            getPersistedSeqNoConsumer()
-        );
-    }
-
-    private TranslogConfig getTranslogConfig(final Path path) {
-        final Settings settings = Settings.builder()
-            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
-            // only randomize between nog age retention and a long one, so failures will have a chance of reproducing
-            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_AGE_SETTING.getKey(), randomBoolean() ? "-1ms" : "1h")
-            .put(IndexSettings.INDEX_TRANSLOG_RETENTION_SIZE_SETTING.getKey(), randomIntBetween(-1, 2048) + "b")
-            .build();
-        return getTranslogConfig(path, settings);
-    }
-
-    private TranslogConfig getTranslogConfig(final Path path, final Settings settings) {
-        final ByteSizeValue bufferSize = randomFrom(
-            TranslogConfig.DEFAULT_BUFFER_SIZE,
-            new ByteSizeValue(8, ByteSizeUnit.KB),
-            new ByteSizeValue(10 + randomInt(128 * 1024), ByteSizeUnit.BYTES)
-        );
-
-        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(shardId.getIndex(), settings);
-        return new TranslogConfig(shardId, path, indexSettings, NON_RECYCLING_INSTANCE, bufferSize);
-    }
-
-    private Location addToTranslogAndList(Translog translog, List<Translog.Operation> list, Translog.Operation op) throws IOException {
-        list.add(op);
-        return translog.add(op);
-    }
-
-    public void testIdParsingFromFile() {
-        long id = randomIntBetween(0, Integer.MAX_VALUE);
-        Path file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id + ".tlog");
-        assertThat(Translog.parseIdFromFileName(file), equalTo(id));
-
-        id = randomIntBetween(0, Integer.MAX_VALUE);
-        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id);
-        try {
-            Translog.parseIdFromFileName(file);
-            fail("invalid pattern");
-        } catch (IllegalArgumentException ex) {
-            // all good
-        }
-
-        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + id + ".recovering");
-        try {
-            Translog.parseIdFromFileName(file);
-            fail("invalid pattern");
-        } catch (IllegalArgumentException ex) {
-            // all good
-        }
-
-        file = translogDir.resolve(Translog.TRANSLOG_FILE_PREFIX + randomNonTranslogPatternString(1, 10) + id);
-        try {
-            Translog.parseIdFromFileName(file);
-            fail("invalid pattern");
-        } catch (IllegalArgumentException ex) {
-            // all good
-        }
-        file = translogDir.resolve(randomNonTranslogPatternString(1, Translog.TRANSLOG_FILE_PREFIX.length() - 1));
-        try {
-            Translog.parseIdFromFileName(file);
-            fail("invalid pattern");
-        } catch (IllegalArgumentException ex) {
-            // all good
-        }
-    }
-
-    private String randomNonTranslogPatternString(int min, int max) {
-        String string;
-        boolean validPathString;
-        do {
-            validPathString = false;
-            string = randomRealisticUnicodeOfCodepointLength(randomIntBetween(min, max));
-            try {
-                final Path resolved = translogDir.resolve(string);
-                // some strings (like '/' , '..') do not refer to a file, which we this method should return
-                validPathString = resolved.getFileName() != null;
-            } catch (InvalidPathException ex) {
-                // some FS don't like our random file names -- let's just skip these random choices
-            }
-        } while (Translog.PARSE_STRICT_ID_PATTERN.matcher(string).matches() || validPathString == false);
-        return string;
-    }
-
-    public void testSimpleOperations() throws IOException {
-        ArrayList<Translog.Operation> ops = new ArrayList<>();
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.size(0));
-        }
-
-        addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
-            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
-        }
-
-        addToTranslogAndList(translog, ops, new Translog.Delete("2", 1, primaryTerm.get()));
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
-            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
-        }
-
-        final long seqNo = randomLongBetween(0, Integer.MAX_VALUE);
-        final String reason = randomAlphaOfLength(16);
-        final long noopTerm = randomLongBetween(1, primaryTerm.get());
-        addToTranslogAndList(translog, ops, new Translog.NoOp(seqNo, noopTerm, reason));
-
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-
-            Translog.Index index = (Translog.Index) snapshot.next();
-            assertNotNull(index);
-            assertThat(BytesReference.toBytes(index.source()), equalTo(new byte[] { 1 }));
-
-            Translog.Delete delete = (Translog.Delete) snapshot.next();
-            assertNotNull(delete);
-            assertThat(delete.id(), equalTo("2"));
-
-            Translog.NoOp noOp = (Translog.NoOp) snapshot.next();
-            assertNotNull(noOp);
-            assertThat(noOp.seqNo(), equalTo(seqNo));
-            assertThat(noOp.primaryTerm(), equalTo(noopTerm));
-            assertThat(noOp.reason(), equalTo(reason));
-
-            assertNull(snapshot.next());
-        }
-
-        long firstId = translog.currentFileGeneration();
-        translog.rollGeneration();
-        assertThat(translog.currentFileGeneration(), Matchers.not(equalTo(firstId)));
-
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
-            assertThat(snapshot.totalOperations(), equalTo(ops.size()));
-        }
-
-        try (Translog.Snapshot snapshot = translog.newSnapshot(seqNo + 1, randomLongBetween(seqNo + 1, Long.MAX_VALUE))) {
-            assertThat(snapshot, SnapshotMatchers.size(0));
-            assertThat(snapshot.totalOperations(), equalTo(0));
-        }
-    }
-
-    protected TranslogStats stats() throws IOException {
-        // force flushing and updating of stats
-        translog.sync();
-        TranslogStats stats = translog.stats();
-        if (randomBoolean()) {
-            BytesStreamOutput out = new BytesStreamOutput();
-            stats.writeTo(out);
-            StreamInput in = out.bytes().streamInput();
-            stats = new TranslogStats(in);
-        }
-        return stats;
-    }
-
-    public void testFindEarliestLastModifiedAge() throws IOException {
-        final int numberOfReaders = scaledRandomIntBetween(1, 10);
-        long fixedTime = randomLongBetween(0, 10000000000000000L);
-        long[] periods = new long[numberOfReaders + 1];
-        long period = randomLongBetween(10000, 1000000);
-        periods[numberOfReaders] = period;
-        TranslogWriter w = mock(TranslogWriter.class);
-        when(w.getLastModifiedTime()).thenReturn(fixedTime - period);
-        assertThat(Translog.findEarliestLastModifiedAge(fixedTime, new ArrayList<>(), w), equalTo(period));
-
-        for (int i = 0; i < numberOfReaders; i++) {
-            periods[i] = randomLongBetween(10000, 1000000);
-        }
-        List<TranslogReader> readers = new ArrayList<>();
-        for (long l : periods) {
-            TranslogReader r = mock(TranslogReader.class);
-            when(r.getLastModifiedTime()).thenReturn(fixedTime - l);
-            readers.add(r);
-        }
-        assertThat(Translog.findEarliestLastModifiedAge(fixedTime, readers, w), equalTo(LongStream.of(periods).max().orElse(0L)));
-    }
-
-    public void testStats() throws IOException {
-        // self control cleaning for test
-        translog.getDeletionPolicy().setRetentionSizeInBytes(1024 * 1024);
-        translog.getDeletionPolicy().setRetentionAgeInMillis(3600 * 1000);
-        final long firstOperationPosition = translog.getFirstOperationPosition();
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(0));
-        }
-        assertThat((int) firstOperationPosition, greaterThan(CodecUtil.headerLength(TranslogHeader.TRANSLOG_CODEC)));
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(1));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(157L));
-            assertThat(stats.getUncommittedOperations(), equalTo(1));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(102L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
-        }
-
-        translog.add(new Translog.Delete("2", 1, primaryTerm.get()));
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(2));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(193L));
-            assertThat(stats.getUncommittedOperations(), equalTo(2));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(138L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
-        }
-
-        translog.add(new Translog.Delete("3", 2, primaryTerm.get()));
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(3));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(229L));
-            assertThat(stats.getUncommittedOperations(), equalTo(3));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(174L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
-        }
-
-        translog.add(new Translog.NoOp(3, 1, randomAlphaOfLength(16)));
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(271L));
-            assertThat(stats.getUncommittedOperations(), equalTo(4));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(216L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
-        }
-
-        translog.rollGeneration();
-        {
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(326L));
-            assertThat(stats.getUncommittedOperations(), equalTo(4));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(271L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(0L));
-        }
-
-        {
-            final TranslogStats stats = stats();
-            final BytesStreamOutput out = new BytesStreamOutput();
-            stats.writeTo(out);
-            final TranslogStats copy = new TranslogStats(out.bytes().streamInput());
-            assertThat(copy.estimatedNumberOfOperations(), equalTo(4));
-            assertThat(copy.getTranslogSizeInBytes(), equalTo(326L));
-
-            try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
-                builder.startObject();
-                copy.toXContent(builder, ToXContent.EMPTY_PARAMS);
-                builder.endObject();
-                assertThat(
-                    Strings.toString(builder),
-                    equalTo(
-                        "{\"translog\":{\"operations\":4,\"size_in_bytes\":"
-                            + 326
-                            + ",\"uncommitted_operations\":4,\"uncommitted_size_in_bytes\":"
-                            + 271
-                            + ",\"earliest_last_modified_age\":"
-                            + stats.getEarliestLastModifiedAge()
-                            + "}}"
-                    )
-                );
-            }
-        }
-        translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(randomLongBetween(3, Long.MAX_VALUE));
-        translog.trimUnreferencedReaders();
-        {
-            long lastModifiedAge = System.currentTimeMillis() - translog.getCurrent().getLastModifiedTime();
-            final TranslogStats stats = stats();
-            assertThat(stats.estimatedNumberOfOperations(), equalTo(4));
-            assertThat(stats.getTranslogSizeInBytes(), equalTo(326L));
-            assertThat(stats.getUncommittedOperations(), equalTo(0));
-            assertThat(stats.getUncommittedSizeInBytes(), equalTo(firstOperationPosition));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
-        }
-    }
-
-    public void testUncommittedOperations() throws Exception {
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        deletionPolicy.setRetentionAgeInMillis(randomLong());
-        deletionPolicy.setRetentionSizeInBytes(randomLong());
-
-        final int operations = scaledRandomIntBetween(10, 100);
-        int uncommittedOps = 0;
-        int operationsInLastGen = 0;
-        for (int i = 0; i < operations; i++) {
-            translog.add(new Translog.Index(Integer.toString(i), i, primaryTerm.get(), new byte[] { 1 }));
-            uncommittedOps++;
-            operationsInLastGen++;
-            if (rarely()) {
-                translog.rollGeneration();
-                operationsInLastGen = 0;
-            }
-            assertThat(translog.stats().getUncommittedOperations(), equalTo(uncommittedOps));
-            if (frequently()) {
-                deletionPolicy.setLocalCheckpointOfSafeCommit(i);
-                assertThat(translog.stats().getUncommittedOperations(), equalTo(operationsInLastGen));
-                uncommittedOps = operationsInLastGen;
-            }
-        }
-    }
-
-    public void testTotalTests() {
-        final TranslogStats total = new TranslogStats();
-
-        assertThat(total.estimatedNumberOfOperations(), equalTo(0));
-        assertThat(total.getTranslogSizeInBytes(), equalTo(0L));
-        assertThat(total.getUncommittedOperations(), equalTo(0));
-        assertThat(total.getUncommittedSizeInBytes(), equalTo(0L));
-        assertThat(total.getEarliestLastModifiedAge(), equalTo(0L));
-
-        final int n = randomIntBetween(1, 16);
-        final List<TranslogStats> statsList = new ArrayList<>(n);
-        long earliestLastModifiedAge = Long.MAX_VALUE;
-        for (int i = 0; i < n; i++) {
-            final TranslogStats stats = new TranslogStats(
-                randomIntBetween(1, 4096),
-                randomIntBetween(1, 1 << 20),
-                randomIntBetween(1, 1 << 20),
-                randomIntBetween(1, 4096),
-                randomIntBetween(1, 1 << 20)
-            );
-            statsList.add(stats);
-            total.add(stats);
-            if (earliestLastModifiedAge > stats.getEarliestLastModifiedAge()) {
-                earliestLastModifiedAge = stats.getEarliestLastModifiedAge();
-            }
-        }
-
-        assertThat(
-            total.estimatedNumberOfOperations(),
-            equalTo(statsList.stream().mapToInt(TranslogStats::estimatedNumberOfOperations).sum())
-        );
-        assertThat(total.getTranslogSizeInBytes(), equalTo(statsList.stream().mapToLong(TranslogStats::getTranslogSizeInBytes).sum()));
-        assertThat(total.getUncommittedOperations(), equalTo(statsList.stream().mapToInt(TranslogStats::getUncommittedOperations).sum()));
-        assertThat(
-            total.getUncommittedSizeInBytes(),
-            equalTo(statsList.stream().mapToLong(TranslogStats::getUncommittedSizeInBytes).sum())
-        );
-        assertThat(total.getEarliestLastModifiedAge(), equalTo(earliestLastModifiedAge));
-    }
-
-    public void testNegativeNumberOfOperations() {
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(-1, 1, 1, 1, 1));
-        assertThat(e, hasToString(containsString("numberOfOperations must be >= 0")));
-        e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, -1, 1, 1));
-        assertThat(e, hasToString(containsString("uncommittedOperations must be >= 0")));
-    }
-
-    public void testNegativeSizeInBytes() {
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, -1, 1, 1, 1));
-        assertThat(e, hasToString(containsString("translogSizeInBytes must be >= 0")));
-        e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, 1, -1, 1));
-        assertThat(e, hasToString(containsString("uncommittedSizeInBytes must be >= 0")));
-    }
-
-    public void testOldestEntryInSeconds() {
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new TranslogStats(1, 1, 1, 1, -1));
-        assertThat(e, hasToString(containsString("earliestLastModifiedAge must be >= 0")));
-    }
-
-    public void testBasicSnapshot() throws IOException {
-        ArrayList<Translog.Operation> ops = new ArrayList<>();
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.size(0));
-        }
-
-        addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-
-        try (Translog.Snapshot snapshot = translog.newSnapshot(0, Long.MAX_VALUE)) {
-            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
-            assertThat(snapshot.totalOperations(), equalTo(1));
-        }
-
-        try (
-            Translog.Snapshot snapshot = translog.newSnapshot(0, randomIntBetween(0, 10));
-            Translog.Snapshot snapshot1 = translog.newSnapshot(0, randomIntBetween(0, 10))
-        ) {
-            assertThat(snapshot, SnapshotMatchers.equalsTo(ops));
-            assertThat(snapshot.totalOperations(), equalTo(1));
-
-            assertThat(snapshot1, SnapshotMatchers.size(1));
-            assertThat(snapshot1.totalOperations(), equalTo(1));
-        }
-    }
-
-    public void testReadLocation() throws IOException {
-        ArrayList<Translog.Operation> ops = new ArrayList<>();
-        ArrayList<Translog.Location> locs = new ArrayList<>();
-        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 })));
-        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 1 })));
-        locs.add(addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 1 })));
-        int i = 0;
-        for (Translog.Operation op : ops) {
-            assertEquals(op, translog.readOperation(locs.get(i++)));
-        }
-        assertNull(translog.readOperation(new Location(100, 0, 0)));
-    }
-
-    public void testSnapshotWithNewTranslog() throws IOException {
-        List<Closeable> toClose = new ArrayList<>();
-        try {
-            ArrayList<Translog.Operation> ops = new ArrayList<>();
-            Translog.Snapshot snapshot = translog.newSnapshot();
-            toClose.add(snapshot);
-            assertThat(snapshot, SnapshotMatchers.size(0));
-
-            addToTranslogAndList(translog, ops, new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-            Translog.Snapshot snapshot1 = translog.newSnapshot();
-            toClose.add(snapshot1);
-
-            addToTranslogAndList(translog, ops, new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 2 }));
-
-            assertThat(snapshot1, SnapshotMatchers.equalsTo(ops.get(0)));
-
-            translog.rollGeneration();
-            addToTranslogAndList(translog, ops, new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 3 }));
-
-            Translog.Snapshot snapshot2 = translog.newSnapshot();
-            toClose.add(snapshot2);
-            translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(2);
-            assertThat(snapshot2, containsOperationsInAnyOrder(ops));
-            assertThat(snapshot2.totalOperations(), equalTo(ops.size()));
-        } finally {
-            IOUtils.closeWhileHandlingException(toClose);
-        }
-    }
-
-    public void testSnapshotOnClosedTranslog() throws IOException {
-        assertTrue(Files.exists(translogDir.resolve(Translog.getFilename(1))));
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-        translog.close();
-        AlreadyClosedException ex = expectThrows(AlreadyClosedException.class, () -> translog.newSnapshot());
-        assertEquals(ex.getMessage(), "translog is already closed");
-    }
-
-    public void testRangeSnapshot() throws Exception {
-        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
-        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
-        final int generations = between(2, 20);
-        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
-        for (int gen = 0; gen < generations; gen++) {
-            Set<Long> seqNos = new HashSet<>();
-            int numOps = randomIntBetween(1, 100);
-            for (int i = 0; i < numOps; i++) {
-                final long seqNo = randomValueOtherThanMany(seqNos::contains, () -> randomLongBetween(0, 1000));
-                minSeqNo = SequenceNumbers.min(minSeqNo, seqNo);
-                maxSeqNo = SequenceNumbers.max(maxSeqNo, seqNo);
-                seqNos.add(seqNo);
-            }
-            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
-            for (long seqNo : seqNos) {
-                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
-                translog.add(op);
-                ops.add(op);
-            }
-            operationsByGen.put(translog.currentFileGeneration(), ops);
-            translog.rollGeneration();
-            if (rarely()) {
-                translog.rollGeneration(); // empty generation
-            }
-        }
-
-        if (minSeqNo > 0) {
-            long fromSeqNo = randomLongBetween(0, minSeqNo - 1);
-            long toSeqNo = randomLongBetween(fromSeqNo, minSeqNo - 1);
-            try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
-                assertThat(snapshot.totalOperations(), equalTo(0));
-                assertNull(snapshot.next());
-            }
-        }
-
-        long fromSeqNo = randomLongBetween(maxSeqNo + 1, Long.MAX_VALUE);
-        long toSeqNo = randomLongBetween(fromSeqNo, Long.MAX_VALUE);
-        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
-            assertThat(snapshot.totalOperations(), equalTo(0));
-            assertNull(snapshot.next());
-        }
-
-        fromSeqNo = randomLongBetween(0, 2000);
-        toSeqNo = randomLongBetween(fromSeqNo, 2000);
-        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo)) {
-            Set<Long> seenSeqNos = new HashSet<>();
-            List<Translog.Operation> expectedOps = new ArrayList<>();
-            for (long gen = translog.currentFileGeneration(); gen > 0; gen--) {
-                for (Translog.Operation op : operationsByGen.getOrDefault(gen, Collections.emptyList())) {
-                    if (fromSeqNo <= op.seqNo() && op.seqNo() <= toSeqNo && seenSeqNos.add(op.seqNo())) {
-                        expectedOps.add(op);
-                    }
-                }
-            }
-            assertThat(TestTranslog.drainSnapshot(snapshot, false), equalTo(expectedOps));
-        }
-    }
-
-    private Long populateTranslogOps(boolean withMissingOps) throws IOException {
-        long minSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
-        long maxSeqNo = SequenceNumbers.NO_OPS_PERFORMED;
-        final int generations = between(2, 20);
-        long currentSeqNo = 0L;
-        List<Translog.Operation> firstGenOps = null;
-        Map<Long, List<Translog.Operation>> operationsByGen = new HashMap<>();
-        for (int gen = 0; gen < generations; gen++) {
-            List<Long> seqNos = new ArrayList<>();
-            int numOps = randomIntBetween(4, 10);
-            for (int i = 0; i < numOps; i++, currentSeqNo++) {
-                minSeqNo = SequenceNumbers.min(minSeqNo, currentSeqNo);
-                maxSeqNo = SequenceNumbers.max(maxSeqNo, currentSeqNo);
-                seqNos.add(currentSeqNo);
-            }
-            Collections.shuffle(seqNos, new Random(100));
-            List<Translog.Operation> ops = new ArrayList<>(seqNos.size());
-            for (long seqNo : seqNos) {
-                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { randomByte() });
-                boolean shouldAdd = !withMissingOps || seqNo % 4 != 0;
-                if (shouldAdd) {
-                    translog.add(op);
-                    ops.add(op);
-                }
-            }
-            operationsByGen.put(translog.currentFileGeneration(), ops);
-            if (firstGenOps == null) {
-                firstGenOps = ops;
-            }
-            translog.rollGeneration();
-            if (rarely()) {
-                translog.rollGeneration(); // empty generation
-            }
-        }
-        return currentSeqNo;
-    }
-
-    public void testFullRangeSnapshot() throws Exception {
-        // Successful snapshot
-        long nextSeqNo = populateTranslogOps(false);
-        long fromSeqNo = 0L;
-        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
-        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
-            int totOps = 0;
-            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
-                totOps++;
-            }
-            assertEquals(totOps, toSeqNo - fromSeqNo + 1);
-        }
-    }
-
-    public void testFullRangeSnapshotWithFailures() throws Exception {
-        long nextSeqNo = populateTranslogOps(true);
-        long fromSeqNo = 0L;
-        long toSeqNo = Math.min(nextSeqNo - 1, fromSeqNo + 15);
-        try (Translog.Snapshot snapshot = translog.newSnapshot(fromSeqNo, toSeqNo, true)) {
-            int totOps = 0;
-            for (Translog.Operation op = snapshot.next(); op != null; op = snapshot.next()) {
-                totOps++;
-            }
-            fail("Should throw exception for missing operations");
-        } catch (MissingHistoryOperationsException e) {
-            assertTrue(e.getMessage().contains("Not all operations between from_seqno"));
-        }
-    }
-
-    public void assertFileIsPresent(Translog translog, long id) {
-        if (Files.exists(translog.location().resolve(Translog.getFilename(id)))) {
-            return;
-        }
-        fail(Translog.getFilename(id) + " is not present in any location: " + translog.location());
-    }
-
-    public void assertFileDeleted(Translog translog, long id) {
-        assertFalse("translog [" + id + "] still exists", Files.exists(translog.location().resolve(Translog.getFilename(id))));
-    }
-
-    private void assertFilePresences(Translog translog) {
-        for (long gen = translog.getMinFileGeneration(); gen < translog.currentFileGeneration(); gen++) {
-            assertFileIsPresent(translog, gen);
-        }
-        for (long gen = 1; gen < translog.getMinFileGeneration(); gen++) {
-            assertFileDeleted(translog, gen);
-        }
-
-    }
-
-    static class LocationOperation implements Comparable<LocationOperation> {
-        final Translog.Operation operation;
-        final Translog.Location location;
-
-        LocationOperation(Translog.Operation operation, Translog.Location location) {
-            this.operation = operation;
-            this.location = location;
-        }
-
-        @Override
-        public int compareTo(LocationOperation o) {
-            return location.compareTo(o.location);
-        }
-    }
-
-    public void testConcurrentWritesWithVaryingSize() throws Throwable {
-        final int opsPerThread = randomIntBetween(10, 200);
-        int threadCount = 2 + randomInt(5);
-
-        logger.info("testing with [{}] threads, each doing [{}] ops", threadCount, opsPerThread);
-        final BlockingQueue<LocationOperation> writtenOperations = new ArrayBlockingQueue<>(threadCount * opsPerThread);
-
-        Thread[] threads = new Thread[threadCount];
-        final Exception[] threadExceptions = new Exception[threadCount];
-        final AtomicLong seqNoGenerator = new AtomicLong();
-        final CountDownLatch downLatch = new CountDownLatch(1);
-        for (int i = 0; i < threadCount; i++) {
-            final int threadId = i;
-            threads[i] = new TranslogThread(
-                translog,
-                downLatch,
-                opsPerThread,
-                threadId,
-                writtenOperations,
-                seqNoGenerator,
-                threadExceptions
-            );
-            threads[i].setDaemon(true);
-            threads[i].start();
-        }
-
-        downLatch.countDown();
-
-        for (int i = 0; i < threadCount; i++) {
-            if (threadExceptions[i] != null) {
-                throw threadExceptions[i];
-            }
-            threads[i].join(60 * 1000);
-        }
-
-        List<LocationOperation> collect = new ArrayList<>(writtenOperations);
-        Collections.sort(collect);
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            for (LocationOperation locationOperation : collect) {
-                Translog.Operation op = snapshot.next();
-                assertNotNull(op);
-                Translog.Operation expectedOp = locationOperation.operation;
-                if (randomBoolean()) {
-                    assertEquals(expectedOp, translog.readOperation(locationOperation.location));
-                }
-                assertEquals(expectedOp.opType(), op.opType());
-                switch (op.opType()) {
-                    case INDEX:
-                        Translog.Index indexOp = (Translog.Index) op;
-                        Translog.Index expIndexOp = (Translog.Index) expectedOp;
-                        assertEquals(expIndexOp.id(), indexOp.id());
-                        assertEquals(expIndexOp.routing(), indexOp.routing());
-                        assertEquals(expIndexOp.source(), indexOp.source());
-                        assertEquals(expIndexOp.version(), indexOp.version());
-                        break;
-                    case DELETE:
-                        Translog.Delete delOp = (Translog.Delete) op;
-                        Translog.Delete expDelOp = (Translog.Delete) expectedOp;
-                        assertEquals(expDelOp.id(), delOp.id());
-                        assertEquals(expDelOp.version(), delOp.version());
-                        break;
-                    case NO_OP:
-                        final Translog.NoOp noOp = (Translog.NoOp) op;
-                        final Translog.NoOp expectedNoOp = (Translog.NoOp) expectedOp;
-                        assertThat(noOp.seqNo(), equalTo(expectedNoOp.seqNo()));
-                        assertThat(noOp.primaryTerm(), equalTo(expectedNoOp.primaryTerm()));
-                        assertThat(noOp.reason(), equalTo(expectedNoOp.reason()));
-                        break;
-                    default:
-                        throw new AssertionError("unsupported operation type [" + op.opType() + "]");
-                }
-            }
-            assertNull(snapshot.next());
-        }
-
-    }
-
-    public void testTranslogCorruption() throws Exception {
-        TranslogConfig config = translog.getConfig();
-        String uuid = translog.getTranslogUUID();
-        List<Translog.Location> locations = new ArrayList<>();
-
-        int translogOperations = randomIntBetween(10, 1000);
-        for (int op = 0; op < translogOperations; op++) {
-            String ascii = randomAlphaOfLengthBetween(1, 50);
-            locations.add(translog.add(new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"))));
-
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-        }
-        translog.close();
-
-        TestTranslog.corruptRandomTranslogFile(logger, random(), translogDir, 0);
-
-        assertThat(expectThrows(TranslogCorruptedException.class, () -> {
-            try (Translog translog = openTranslog(config, uuid); Translog.Snapshot snapshot = translog.newSnapshot()) {
-                for (int i = 0; i < locations.size(); i++) {
-                    snapshot.next();
-                }
-            }
-        }).getMessage(), containsString(translogDir.toString()));
-
-        expectIntactTranslog = false;
-    }
-
-    public void testTruncatedTranslogs() throws Exception {
-        List<Translog.Location> locations = new ArrayList<>();
-
-        int translogOperations = randomIntBetween(10, 100);
-        for (int op = 0; op < translogOperations; op++) {
-            String ascii = randomAlphaOfLengthBetween(1, 50);
-            locations.add(translog.add(new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"))));
-        }
-        translog.sync();
-
-        truncateTranslogs(translogDir);
-
-        AtomicInteger truncations = new AtomicInteger(0);
-        try (Translog.Snapshot snap = translog.newSnapshot()) {
-            for (int i = 0; i < locations.size(); i++) {
-                try {
-                    assertNotNull(snap.next());
-                } catch (TranslogCorruptedException e) {
-                    assertThat(e.getCause(), instanceOf(EOFException.class));
-                    truncations.incrementAndGet();
-                }
-            }
-        }
-        assertThat("at least one truncation was caused and caught", truncations.get(), greaterThanOrEqualTo(1));
-    }
-
-    /**
-     * Randomly truncate some bytes in the translog files
-     */
-    private void truncateTranslogs(Path directory) throws Exception {
-        Path[] files = FileSystemUtils.files(directory, "translog-*");
-        for (Path file : files) {
-            try (FileChannel f = FileChannel.open(file, StandardOpenOption.READ, StandardOpenOption.WRITE)) {
-                long prevSize = f.size();
-                long newSize = prevSize - randomIntBetween(1, (int) prevSize / 2);
-                logger.info("--> truncating {}, prev: {}, now: {}", file, prevSize, newSize);
-                f.truncate(newSize);
-            }
-        }
-    }
-
-    private Term newUid(ParsedDocument doc) {
-        return new Term("_id", Uid.encodeId(doc.id()));
-    }
-
-    private Term newUid(String id) {
-        return new Term("_id", Uid.encodeId(id));
-    }
-
-    public void testVerifyTranslogIsNotDeleted() throws IOException {
-        assertFileIsPresent(translog, 1);
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, SnapshotMatchers.size(1));
-            assertFileIsPresent(translog, 1);
-            assertThat(snapshot.totalOperations(), equalTo(1));
-        }
-        translog.close();
-        assertFileDeleted(translog, 1);
-        assertFileIsPresent(translog, 2);
-    }
-
-    /**
-     * Tests that concurrent readers and writes maintain view and snapshot semantics
-     */
-    public void testConcurrentWriteViewsAndSnapshot() throws Throwable {
-        final Thread[] writers = new Thread[randomIntBetween(1, 3)];
-        final Thread[] readers = new Thread[randomIntBetween(1, 3)];
-        final int flushEveryOps = randomIntBetween(5, 100);
-        final int maxOps = randomIntBetween(200, 1000);
-        final Object signalReaderSomeDataWasIndexed = new Object();
-        final AtomicLong idGenerator = new AtomicLong();
-        final CyclicBarrier barrier = new CyclicBarrier(writers.length + readers.length + 1);
-
-        // a map of all written ops and their returned location.
-        final Map<Translog.Operation, Translog.Location> writtenOps = ConcurrentCollections.newConcurrentMap();
-
-        // a signal for all threads to stop
-        final AtomicBoolean run = new AtomicBoolean(true);
-
-        final Object flushMutex = new Object();
-        final AtomicLong lastCommittedLocalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        final LocalCheckpointTracker tracker = LocalCheckpointTrackerTests.createEmptyTracker();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        // any errors on threads
-        final List<Exception> errors = new CopyOnWriteArrayList<>();
-        logger.info("using [{}] readers. [{}] writers. flushing every ~[{}] ops.", readers.length, writers.length, flushEveryOps);
-        for (int i = 0; i < writers.length; i++) {
-            final String threadName = "writer_" + i;
-            final int threadId = i;
-            writers[i] = new Thread(new AbstractRunnable() {
-                @Override
-                public void doRun() throws BrokenBarrierException, InterruptedException, IOException {
-                    barrier.await();
-                    int counter = 0;
-                    while (run.get() && idGenerator.get() < maxOps) {
-                        long id = idGenerator.getAndIncrement();
-                        final Translog.Operation op;
-                        final Translog.Operation.Type type = Translog.Operation.Type.values()[((int) (id % Translog.Operation.Type
-                            .values().length))];
-                        switch (type) {
-                            case CREATE:
-                            case INDEX:
-                                op = new Translog.Index("" + id, id, primaryTerm.get(), new byte[] { (byte) id });
-                                break;
-                            case DELETE:
-                                op = new Translog.Delete(Long.toString(id), id, primaryTerm.get());
-                                break;
-                            case NO_OP:
-                                op = new Translog.NoOp(id, 1, Long.toString(id));
-                                break;
-                            default:
-                                throw new AssertionError("unsupported operation type [" + type + "]");
-                        }
-                        Translog.Location location = translog.add(op);
-                        tracker.markSeqNoAsProcessed(id);
-                        Translog.Location existing = writtenOps.put(op, location);
-                        if (existing != null) {
-                            fail("duplicate op [" + op + "], old entry at " + location);
-                        }
-                        if (id % writers.length == threadId) {
-                            translog.ensureSynced(location);
-                        }
-                        if (id % flushEveryOps == 0) {
-                            synchronized (flushMutex) {
-                                // we need not do this concurrently as we need to make sure that the generation
-                                // we're committing - is still present when we're committing
-                                long localCheckpoint = tracker.getProcessedCheckpoint();
-                                translog.rollGeneration();
-                                // expose the new checkpoint (simulating a commit), before we trim the translog
-                                lastCommittedLocalCheckpoint.set(localCheckpoint);
-                                deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
-                                translog.trimUnreferencedReaders();
-                            }
-                        }
-                        if (id % 7 == 0) {
-                            synchronized (signalReaderSomeDataWasIndexed) {
-                                signalReaderSomeDataWasIndexed.notifyAll();
-                            }
-                        }
-                        counter++;
-                    }
-                    logger.info("--> [{}] done. wrote [{}] ops.", threadName, counter);
-                }
-
-                @Override
-                public void onFailure(Exception e) {
-                    logger.error(() -> new ParameterizedMessage("--> writer [{}] had an error", threadName), e);
-                    errors.add(e);
-                }
-            }, threadName);
-            writers[i].start();
-        }
-
-        for (int i = 0; i < readers.length; i++) {
-            final String threadId = "reader_" + i;
-            readers[i] = new Thread(new AbstractRunnable() {
-                Closeable retentionLock = null;
-                long committedLocalCheckpointAtView;
-
-                @Override
-                public void onFailure(Exception e) {
-                    logger.error(() -> new ParameterizedMessage("--> reader [{}] had an error", threadId), e);
-                    errors.add(e);
-                    try {
-                        closeRetentionLock();
-                    } catch (IOException inner) {
-                        inner.addSuppressed(e);
-                        logger.error("unexpected error while closing view, after failure", inner);
-                    }
-                }
-
-                void closeRetentionLock() throws IOException {
-                    if (retentionLock != null) {
-                        retentionLock.close();
-                    }
-                }
-
-                void acquireRetentionLock() throws IOException {
-                    closeRetentionLock();
-                    retentionLock = translog.acquireRetentionLock();
-                    // captures the last committed checkpoint, while holding the view, simulating
-                    // recovery logic which captures a view and gets a lucene commit
-                    committedLocalCheckpointAtView = lastCommittedLocalCheckpoint.get();
-                    logger.info("--> [{}] min gen after acquiring lock [{}]", threadId, translog.getMinFileGeneration());
-                }
-
-                @Override
-                protected void doRun() throws Exception {
-                    barrier.await();
-                    int iter = 0;
-                    while (idGenerator.get() < maxOps) {
-                        if (iter++ % 10 == 0) {
-                            acquireRetentionLock();
-                        }
-
-                        // captures al views that are written since the view was created (with a small caveat see bellow)
-                        // these are what we expect the snapshot to return (and potentially some more).
-                        Set<Translog.Operation> expectedOps = new HashSet<>(writtenOps.keySet());
-                        expectedOps.removeIf(op -> op.seqNo() <= committedLocalCheckpointAtView);
-                        try (Translog.Snapshot snapshot = translog.newSnapshot(committedLocalCheckpointAtView + 1L, Long.MAX_VALUE)) {
-                            Translog.Operation op;
-                            while ((op = snapshot.next()) != null) {
-                                expectedOps.remove(op);
-                            }
-                        }
-                        if (expectedOps.isEmpty() == false) {
-                            StringBuilder missed = new StringBuilder("missed ").append(expectedOps.size())
-                                .append(" operations from [")
-                                .append(committedLocalCheckpointAtView + 1L)
-                                .append("]");
-                            boolean failed = false;
-                            for (Translog.Operation expectedOp : expectedOps) {
-                                final Translog.Location loc = writtenOps.get(expectedOp);
-                                failed = true;
-                                missed.append("\n --> [").append(expectedOp).append("] written at ").append(loc);
-                            }
-                            if (failed) {
-                                fail(missed.toString());
-                            }
-                        }
-                        // slow down things a bit and spread out testing..
-                        synchronized (signalReaderSomeDataWasIndexed) {
-                            if (idGenerator.get() < maxOps) {
-                                signalReaderSomeDataWasIndexed.wait();
-                            }
-                        }
-                    }
-                    closeRetentionLock();
-                    logger.info("--> [{}] done. tested [{}] snapshots", threadId, iter);
-                }
-            }, threadId);
-            readers[i].start();
-        }
-
-        barrier.await();
-        logger.debug("--> waiting for threads to stop");
-        for (Thread thread : writers) {
-            thread.join();
-        }
-        logger.debug("--> waiting for readers to stop");
-        // force stopping, if all writers crashed
-        synchronized (signalReaderSomeDataWasIndexed) {
-            idGenerator.set(Long.MAX_VALUE);
-            signalReaderSomeDataWasIndexed.notifyAll();
-        }
-        for (Thread thread : readers) {
-            thread.join();
-        }
-        if (errors.size() > 0) {
-            Throwable e = errors.get(0);
-            for (Throwable suppress : errors.subList(1, errors.size())) {
-                e.addSuppressed(suppress);
-            }
-            throw e;
-        }
-        logger.info("--> test done. total ops written [{}]", writtenOps.size());
-    }
-
-    public void testSyncUpTo() throws IOException {
-        int translogOperations = randomIntBetween(10, 100);
-        int count = 0;
-        for (int op = 0; op < translogOperations; op++) {
-            int seqNo = ++count;
-            final Translog.Location location = translog.add(
-                new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
-            );
-            if (randomBoolean()) {
-                assertTrue("at least one operation pending", translog.syncNeeded());
-                assertTrue("this operation has not been synced", translog.ensureSynced(location));
-                // we are the last location so everything should be synced
-                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
-                seqNo = ++count;
-                translog.add(
-                    new Translog.Index("" + op, seqNo, primaryTerm.get(), Integer.toString(seqNo).getBytes(Charset.forName("UTF-8")))
-                );
-                assertTrue("one pending operation", translog.syncNeeded());
-                assertFalse("this op has been synced before", translog.ensureSynced(location)); // not syncing now
-                assertTrue("we only synced a previous operation yet", translog.syncNeeded());
-            }
-            if (rarely()) {
-                translog.rollGeneration();
-                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(location)); // not syncing now
-                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
-            }
-
-            if (randomBoolean()) {
-                translog.sync();
-                assertFalse("translog has been synced already", translog.ensureSynced(location));
-            }
-        }
-    }
-
-    public void testSyncUpToStream() throws IOException {
-        int iters = randomIntBetween(5, 10);
-        for (int i = 0; i < iters; i++) {
-            int translogOperations = randomIntBetween(10, 100);
-            int count = 0;
-            ArrayList<Location> locations = new ArrayList<>();
-            for (int op = 0; op < translogOperations; op++) {
-                if (rarely()) {
-                    translog.rollGeneration();
-                }
-                final Translog.Location location = translog.add(
-                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
-                );
-                locations.add(location);
-            }
-            Collections.shuffle(locations, random());
-            if (randomBoolean()) {
-                assertTrue("at least one operation pending", translog.syncNeeded());
-                assertTrue("this operation has not been synced", translog.ensureSynced(locations.stream()));
-                // we are the last location so everything should be synced
-                assertFalse("the last call to ensureSycned synced all previous ops", translog.syncNeeded());
-            } else if (rarely()) {
-                translog.rollGeneration();
-                // not syncing now
-                assertFalse("location is from a previous translog - already synced", translog.ensureSynced(locations.stream()));
-                assertFalse("no sync needed since no operations in current translog", translog.syncNeeded());
-            } else {
-                translog.sync();
-                assertFalse("translog has been synced already", translog.ensureSynced(locations.stream()));
-            }
-            for (Location location : locations) {
-                assertFalse("all of the locations should be synced: " + location, translog.ensureSynced(location));
-            }
-        }
-    }
-
-    public void testLocationComparison() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        int count = 0;
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(
-                    new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(++count).getBytes(Charset.forName("UTF-8")))
-                )
-            );
-            if (rarely() && translogOperations > op + 1) {
-                translog.rollGeneration();
-            }
-        }
-        Collections.shuffle(locations, random());
-        Translog.Location max = locations.get(0);
-        for (Translog.Location location : locations) {
-            max = max(max, location);
-        }
-
-        assertEquals(max.generation, translog.currentFileGeneration());
-        try (Translog.Snapshot snap = new SortedSnapshot(translog.newSnapshot())) {
-            Translog.Operation next;
-            Translog.Operation maxOp = null;
-            while ((next = snap.next()) != null) {
-                maxOp = next;
-            }
-            assertNotNull(maxOp);
-            assertEquals(maxOp.getSource().source.utf8ToString(), Integer.toString(count));
-        }
-    }
-
-    public static Translog.Location max(Translog.Location a, Translog.Location b) {
-        if (a.compareTo(b) > 0) {
-            return a;
-        }
-        return b;
-    }
-
-    public void testBasicCheckpoint() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        int lastSynced = -1;
-        long lastSyncedGlobalCheckpoint = globalCheckpoint.get();
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
-            );
-            if (randomBoolean()) {
-                globalCheckpoint.set(globalCheckpoint.get() + randomIntBetween(1, 16));
-            }
-            if (frequently()) {
-                translog.sync();
-                lastSynced = op;
-                lastSyncedGlobalCheckpoint = globalCheckpoint.get();
-            }
-        }
-        assertEquals(translogOperations, translog.totalOperations());
-        translog.add(
-            new Translog.Index(
-                "" + translogOperations,
-                translogOperations,
-                primaryTerm.get(),
-                Integer.toString(translogOperations).getBytes(Charset.forName("UTF-8"))
-            )
-        );
-
-        final Checkpoint checkpoint = Checkpoint.read(translog.location().resolve(Translog.CHECKPOINT_FILE_NAME));
-        try (
-            TranslogReader reader = translog.openReader(
-                translog.location().resolve(Translog.getFilename(translog.currentFileGeneration())),
-                checkpoint
-            )
-        ) {
-            assertEquals(lastSynced + 1, reader.totalOperations());
-            TranslogSnapshot snapshot = reader.newSnapshot();
-
-            for (int op = 0; op < translogOperations; op++) {
-                if (op <= lastSynced) {
-                    final Translog.Operation read = snapshot.next();
-                    assertEquals(Integer.toString(op), read.getSource().source.utf8ToString());
-                } else {
-                    Translog.Operation next = snapshot.next();
-                    assertNull(next);
-                }
-            }
-            Translog.Operation next = snapshot.next();
-            assertNull(next);
-        }
-        assertEquals(translogOperations + 1, translog.totalOperations());
-        assertThat(checkpoint.globalCheckpoint, equalTo(lastSyncedGlobalCheckpoint));
-        translog.close();
-    }
-
-    public void testTranslogWriter() throws IOException {
-        final TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1);
-        final Set<Long> persistedSeqNos = new HashSet<>();
-        persistedSeqNoConsumer.set(persistedSeqNos::add);
-        final int numOps = scaledRandomIntBetween(8, 250000);
-        final Set<Long> seenSeqNos = new HashSet<>();
-        boolean opsHaveValidSequenceNumbers = randomBoolean();
-        for (int i = 0; i < numOps; i++) {
-            byte[] bytes = new byte[4];
-            DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
-            out.writeInt(i);
-            long seqNo;
-            do {
-                seqNo = opsHaveValidSequenceNumbers ? randomNonNegativeLong() : SequenceNumbers.UNASSIGNED_SEQ_NO;
-                opsHaveValidSequenceNumbers = opsHaveValidSequenceNumbers || !rarely();
-            } while (seenSeqNos.contains(seqNo));
-            if (seqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
-                seenSeqNos.add(seqNo);
-            }
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), seqNo);
-        }
-        assertThat(persistedSeqNos, empty());
-        writer.sync();
-        persistedSeqNos.remove(SequenceNumbers.UNASSIGNED_SEQ_NO);
-        assertEquals(seenSeqNos, persistedSeqNos);
-
-        final BaseTranslogReader reader = randomBoolean()
-            ? writer
-            : translog.openReader(writer.path(), Checkpoint.read(translog.location().resolve(Translog.CHECKPOINT_FILE_NAME)));
-        for (int i = 0; i < numOps; i++) {
-            ByteBuffer buffer = ByteBuffer.allocate(4);
-            reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
-            buffer.flip();
-            final int value = buffer.getInt();
-            assertEquals(i, value);
-        }
-        final long minSeqNo = seenSeqNos.stream().min(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
-        final long maxSeqNo = seenSeqNos.stream().max(Long::compareTo).orElse(SequenceNumbers.NO_OPS_PERFORMED);
-        assertThat(reader.getCheckpoint().minSeqNo, equalTo(minSeqNo));
-        assertThat(reader.getCheckpoint().maxSeqNo, equalTo(maxSeqNo));
-
-        byte[] bytes = new byte[4];
-        DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
-        out.writeInt(2048);
-        writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
-
-        if (reader instanceof TranslogReader) {
-            ByteBuffer buffer = ByteBuffer.allocate(4);
-            try {
-                reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * numOps);
-                fail("read past EOF?");
-            } catch (EOFException ex) {
-                // expected
-            }
-            ((TranslogReader) reader).close();
-        } else {
-            // live reader!
-            ByteBuffer buffer = ByteBuffer.allocate(4);
-            final long pos = reader.getFirstOperationOffset() + 4 * numOps;
-            reader.readBytes(buffer, pos);
-            buffer.flip();
-            final int value = buffer.getInt();
-            assertEquals(2048, value);
-        }
-        IOUtils.close(writer);
-    }
-
-    public void testTranslogWriterCanFlushInAddOrReadCall() throws IOException {
-        Path tempDir = createTempDir();
-        final TranslogConfig temp = getTranslogConfig(tempDir);
-        final TranslogConfig config = new TranslogConfig(
-            temp.getShardId(),
-            temp.getTranslogPath(),
-            temp.getIndexSettings(),
-            temp.getBigArrays(),
-            new ByteSizeValue(1, ByteSizeUnit.KB)
-        );
-
-        final Set<Long> persistedSeqNos = new HashSet<>();
-        final AtomicInteger writeCalls = new AtomicInteger();
-
-        final ChannelFactory channelFactory = (file, openOption) -> {
-            FileChannel delegate = FileChannel.open(file, openOption);
-            boolean success = false;
-            try {
-                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
-                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
-
-                final FileChannel channel;
-                if (isCkpFile) {
-                    channel = delegate;
-                } else {
-                    channel = new FilterFileChannel(delegate) {
-
-                        @Override
-                        public int write(ByteBuffer src) throws IOException {
-                            writeCalls.incrementAndGet();
-                            return super.write(src);
-                        }
-                    };
-                }
-                success = true;
-                return channel;
-            } finally {
-                if (success == false) {
-                    IOUtils.closeWhileHandlingException(delegate);
-                }
-            }
-        };
-
-        String translogUUID = Translog.createEmptyTranslog(
-            config.getTranslogPath(),
-            SequenceNumbers.NO_OPS_PERFORMED,
-            shardId,
-            channelFactory,
-            primaryTerm.get()
-        );
-
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                new DefaultTranslogDeletionPolicy(-1, -1, 0),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                persistedSeqNos::add
-            ) {
-                @Override
-                ChannelFactory getChannelFactory() {
-                    return channelFactory;
-                }
-            }
-        ) {
-            TranslogWriter writer = translog.getCurrent();
-            int initialWriteCalls = writeCalls.get();
-            byte[] bytes = new byte[256];
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 3);
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 4);
-            assertThat(persistedSeqNos, empty());
-            assertEquals(initialWriteCalls, writeCalls.get());
-
-            if (randomBoolean()) {
-                // Since the buffer is full, this will flush before performing the add.
-                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
-                assertThat(persistedSeqNos, empty());
-                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
-            } else {
-                // Will flush on read
-                writer.readBytes(ByteBuffer.allocate(256), 0);
-                assertThat(persistedSeqNos, empty());
-                assertThat(writeCalls.get(), greaterThan(initialWriteCalls));
-
-                // Add after we the read flushed the buffer
-                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 5);
-            }
-
-            writer.sync();
-
-            // Sequence numbers are marked as persisted after sync
-            assertThat(persistedSeqNos, contains(1L, 2L, 3L, 4L, 5L));
-        }
-    }
-
-    public void testTranslogWriterDoesNotBlockAddsOnWrite() throws IOException, InterruptedException {
-        Path tempDir = createTempDir();
-        final TranslogConfig config = getTranslogConfig(tempDir);
-        final AtomicBoolean startBlocking = new AtomicBoolean(false);
-        final CountDownLatch writeStarted = new CountDownLatch(1);
-        final CountDownLatch blocker = new CountDownLatch(1);
-        final Set<Long> persistedSeqNos = new HashSet<>();
-
-        final ChannelFactory channelFactory = (file, openOption) -> {
-            FileChannel delegate = FileChannel.open(file, openOption);
-            boolean success = false;
-            try {
-                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
-                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
-
-                final FileChannel channel;
-                if (isCkpFile) {
-                    channel = delegate;
-                } else {
-                    channel = new FilterFileChannel(delegate) {
-
-                        @Override
-                        public int write(ByteBuffer src) throws IOException {
-                            if (startBlocking.get()) {
-                                if (writeStarted.getCount() > 0) {
-                                    writeStarted.countDown();
-                                }
-                                try {
-                                    blocker.await();
-                                } catch (InterruptedException e) {
-                                    // Ignore
-                                }
-                            }
-                            return super.write(src);
-                        }
-
-                        @Override
-                        public void force(boolean metaData) throws IOException {
-                            if (startBlocking.get()) {
-                                if (writeStarted.getCount() > 0) {
-                                    writeStarted.countDown();
-                                }
-                                try {
-                                    blocker.await();
-                                } catch (InterruptedException e) {
-                                    // Ignore
-                                }
-                            }
-                            super.force(metaData);
-                        }
-                    };
-                }
-                success = true;
-                return channel;
-            } finally {
-                if (success == false) {
-                    IOUtils.closeWhileHandlingException(delegate);
-                }
-            }
-        };
-        String translogUUID = Translog.createEmptyTranslog(
-            config.getTranslogPath(),
-            SequenceNumbers.NO_OPS_PERFORMED,
-            shardId,
-            channelFactory,
-            primaryTerm.get()
-        );
-
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                new DefaultTranslogDeletionPolicy(-1, -1, 0),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                persistedSeqNos::add
-            ) {
-                @Override
-                ChannelFactory getChannelFactory() {
-                    return channelFactory;
-                }
-            }
-        ) {
-            TranslogWriter writer = translog.getCurrent();
-
-            byte[] bytes = new byte[4];
-            DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(new byte[4]));
-            out.writeInt(1);
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 1);
-            assertThat(persistedSeqNos, empty());
-            startBlocking.set(true);
-            Thread thread = new Thread(() -> {
-                try {
-                    writer.sync();
-                } catch (IOException e) {
-                    throw new AssertionError(e);
-                }
-            });
-            thread.start();
-            writeStarted.await();
-
-            // Add will not block even though we are currently writing/syncing
-            writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), 2);
-
-            blocker.countDown();
-            // Sync against so that both operations are written
-            writer.sync();
-
-            assertThat(persistedSeqNos, contains(1L, 2L));
-            thread.join();
-        }
-    }
-
-    public void testCloseIntoReader() throws IOException {
-        try (TranslogWriter writer = translog.createWriter(translog.currentFileGeneration() + 1)) {
-            final int numOps = randomIntBetween(8, 128);
-            for (int i = 0; i < numOps; i++) {
-                final byte[] bytes = new byte[4];
-                final DataOutput out = EndiannessReverserUtil.wrapDataOutput(new ByteArrayDataOutput(bytes));
-                out.writeInt(i);
-                writer.add(ReleasableBytesReference.wrap(new BytesArray(bytes)), randomNonNegativeLong());
-            }
-            writer.sync();
-            final Checkpoint writerCheckpoint = writer.getCheckpoint();
-            TranslogReader reader = writer.closeIntoReader();
-            try {
-                if (randomBoolean()) {
-                    reader.close();
-                    reader = translog.openReader(reader.path(), writerCheckpoint);
-                }
-                for (int i = 0; i < numOps; i++) {
-                    final ByteBuffer buffer = ByteBuffer.allocate(4);
-                    reader.readBytes(buffer, reader.getFirstOperationOffset() + 4 * i);
-                    buffer.flip();
-                    final int value = buffer.getInt();
-                    assertEquals(i, value);
-                }
-                final Checkpoint readerCheckpoint = reader.getCheckpoint();
-                assertThat(readerCheckpoint, equalTo(writerCheckpoint));
-            } finally {
-                IOUtils.close(reader);
-            }
-        }
-    }
-
-    public void testBasicRecovery() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        Translog.TranslogGeneration translogGeneration = null;
-        int minUncommittedOp = -1;
-        final boolean commitOften = randomBoolean();
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
-            );
-            final boolean commit = commitOften ? frequently() : rarely();
-            if (commit && op < translogOperations - 1) {
-                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(op);
-                minUncommittedOp = op + 1;
-                translogGeneration = translog.getGeneration();
-            }
-        }
-        translog.sync();
-        TranslogConfig config = translog.getConfig();
-
-        translog.close();
-        if (translogGeneration == null) {
-            translog = createTranslog(config);
-            assertEquals(0, translog.stats().estimatedNumberOfOperations());
-            assertEquals(2, translog.currentFileGeneration());
-            assertFalse(translog.syncNeeded());
-            try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-                assertNull(snapshot.next());
-            }
-        } else {
-            translog = new Translog(
-                config,
-                translogGeneration.translogUUID,
-                translog.getDeletionPolicy(),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            );
-            assertEquals(
-                "lastCommitted must be 1 less than current",
-                translogGeneration.translogFileGeneration + 1,
-                translog.currentFileGeneration()
-            );
-            assertFalse(translog.syncNeeded());
-            try (Translog.Snapshot snapshot = translog.newSnapshot(minUncommittedOp, Long.MAX_VALUE)) {
-                for (int i = minUncommittedOp; i < translogOperations; i++) {
-                    assertEquals(
-                        "expected operation" + i + " to be in the previous translog but wasn't",
-                        translog.currentFileGeneration() - 1,
-                        locations.get(i).generation
-                    );
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null", next);
-                    assertEquals(i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-        }
-    }
-
-    public void testRecoveryUncommitted() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        final int prepareOp = randomIntBetween(0, translogOperations - 1);
-        Translog.TranslogGeneration translogGeneration = null;
-        final boolean sync = randomBoolean();
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
-            );
-            if (op == prepareOp) {
-                translogGeneration = translog.getGeneration();
-                translog.rollGeneration();
-                assertEquals(
-                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
-                    2L,
-                    translogGeneration.translogFileGeneration
-                );
-                assertNotNull(translogGeneration.translogUUID);
-            }
-        }
-        if (sync) {
-            translog.sync();
-        }
-        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
-        // translog here as well.
-        TranslogConfig config = translog.getConfig();
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            assertNotNull(translogGeneration);
-            assertEquals(
-                "lastCommitted must be 2 less than current - we never finished the commit",
-                translogGeneration.translogFileGeneration + 2,
-                translog.currentFileGeneration()
-            );
-            assertFalse(translog.syncNeeded());
-            try (Translog.Snapshot snapshot = new SortedSnapshot(translog.newSnapshot())) {
-                int upTo = sync ? translogOperations : prepareOp;
-                for (int i = 0; i < upTo; i++) {
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
-                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-        }
-        if (randomBoolean()) { // recover twice
-            try (
-                Translog translog = new Translog(
-                    config,
-                    translogUUID,
-                    deletionPolicy,
-                    () -> SequenceNumbers.NO_OPS_PERFORMED,
-                    primaryTerm::get,
-                    seqNo -> {}
-                )
-            ) {
-                assertNotNull(translogGeneration);
-                assertEquals(
-                    "lastCommitted must be 3 less than current - we never finished the commit and run recovery twice",
-                    translogGeneration.translogFileGeneration + 3,
-                    translog.currentFileGeneration()
-                );
-                assertFalse(translog.syncNeeded());
-                try (Translog.Snapshot snapshot = new SortedSnapshot(translog.newSnapshot())) {
-                    int upTo = sync ? translogOperations : prepareOp;
-                    for (int i = 0; i < upTo; i++) {
-                        Translog.Operation next = snapshot.next();
-                        assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
-                        assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                    }
-                }
-            }
-        }
-    }
-
-    public void testRecoveryUncommittedFileExists() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        final int prepareOp = randomIntBetween(0, translogOperations - 1);
-        Translog.TranslogGeneration translogGeneration = null;
-        final boolean sync = randomBoolean();
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
-            );
-            if (op == prepareOp) {
-                translogGeneration = translog.getGeneration();
-                translog.rollGeneration();
-                assertEquals(
-                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
-                    2L,
-                    translogGeneration.translogFileGeneration
-                );
-                assertNotNull(translogGeneration.translogUUID);
-            }
-        }
-        if (sync) {
-            translog.sync();
-        }
-        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
-        // translog here as well.
-        TranslogConfig config = translog.getConfig();
-        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
-        Checkpoint read = Checkpoint.read(ckp);
-        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
-
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            assertNotNull(translogGeneration);
-            assertEquals(
-                "lastCommitted must be 2 less than current - we never finished the commit",
-                translogGeneration.translogFileGeneration + 2,
-                translog.currentFileGeneration()
-            );
-            assertFalse(translog.syncNeeded());
-            try (Translog.Snapshot snapshot = new SortedSnapshot(translog.newSnapshot())) {
-                int upTo = sync ? translogOperations : prepareOp;
-                for (int i = 0; i < upTo; i++) {
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
-                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-        }
-
-        if (randomBoolean()) { // recover twice
-            try (
-                Translog translog = new Translog(
-                    config,
-                    translogUUID,
-                    deletionPolicy,
-                    () -> SequenceNumbers.NO_OPS_PERFORMED,
-                    primaryTerm::get,
-                    seqNo -> {}
-                )
-            ) {
-                assertNotNull(translogGeneration);
-                assertEquals(
-                    "lastCommitted must be 3 less than current - we never finished the commit and run recovery twice",
-                    translogGeneration.translogFileGeneration + 3,
-                    translog.currentFileGeneration()
-                );
-                assertFalse(translog.syncNeeded());
-                try (Translog.Snapshot snapshot = new SortedSnapshot(translog.newSnapshot())) {
-                    int upTo = sync ? translogOperations : prepareOp;
-                    for (int i = 0; i < upTo; i++) {
-                        Translog.Operation next = snapshot.next();
-                        assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
-                        assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                    }
-                }
-            }
-        }
-    }
-
-    public void testRecoveryUncommittedCorruptedCheckpoint() throws IOException {
-        int translogOperations = 100;
-        final int prepareOp = 44;
-        Translog.TranslogGeneration translogGeneration = null;
-        final boolean sync = randomBoolean();
-        for (int op = 0; op < translogOperations; op++) {
-            translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(StandardCharsets.UTF_8)));
-            if (op == prepareOp) {
-                translogGeneration = translog.getGeneration();
-                translog.rollGeneration();
-                assertEquals(
-                    "expected this to be the first roll (1 gen is on creation, 2 when opened)",
-                    2L,
-                    translogGeneration.translogFileGeneration
-                );
-                assertNotNull(translogGeneration.translogUUID);
-            }
-        }
-        translog.sync();
-        // we intentionally don't close the tlog that is in the prepareCommit stage since we try to recovery the uncommitted
-        // translog here as well.
-        TranslogConfig config = translog.getConfig();
-        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
-        Checkpoint read = Checkpoint.read(ckp);
-        Checkpoint corrupted = Checkpoint.emptyTranslogCheckpoint(0, 0, SequenceNumbers.NO_OPS_PERFORMED, 0);
-        Checkpoint.write(
-            FileChannel::open,
-            config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)),
-            corrupted,
-            StandardOpenOption.WRITE,
-            StandardOpenOption.CREATE_NEW
-        );
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        final TranslogCorruptedException translogCorruptedException = expectThrows(
-            TranslogCorruptedException.class,
-            () -> new Translog(config, translogUUID, deletionPolicy, () -> SequenceNumbers.NO_OPS_PERFORMED, primaryTerm::get, seqNo -> {})
-        );
-        assertThat(
-            translogCorruptedException.getMessage(),
-            endsWith(
-                "] is corrupted, checkpoint file translog-3.ckp already exists but has corrupted content: expected Checkpoint{offset=2750, "
-                    + "numOps=55, generation=3, minSeqNo=45, maxSeqNo=99, globalCheckpoint=-1, minTranslogGeneration=1, trimmedAboveSeqNo=-2} "
-                    + "but got Checkpoint{offset=0, numOps=0, generation=0, minSeqNo=-1, maxSeqNo=-1, globalCheckpoint=-1, "
-                    + "minTranslogGeneration=0, trimmedAboveSeqNo=-2}"
-            )
-        );
-        Checkpoint.write(
-            FileChannel::open,
-            config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)),
-            read,
-            StandardOpenOption.WRITE,
-            StandardOpenOption.TRUNCATE_EXISTING
-        );
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            assertNotNull(translogGeneration);
-            assertEquals(
-                "lastCommitted must be 2 less than current - we never finished the commit",
-                translogGeneration.translogFileGeneration + 2,
-                translog.currentFileGeneration()
-            );
-            assertFalse(translog.syncNeeded());
-            try (Translog.Snapshot snapshot = new SortedSnapshot(translog.newSnapshot())) {
-                int upTo = sync ? translogOperations : prepareOp;
-                for (int i = 0; i < upTo; i++) {
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null synced: " + sync, next);
-                    assertEquals("payload mismatch, synced: " + sync, i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-        }
-    }
-
-    public void testSnapshotFromStreamInput() throws IOException {
-        BytesStreamOutput out = new BytesStreamOutput();
-        List<Translog.Operation> ops = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        for (int op = 0; op < translogOperations; op++) {
-            Translog.Index test = new Translog.Index(
-                "" + op,
-                op,
-                primaryTerm.get(),
-                Integer.toString(op).getBytes(Charset.forName("UTF-8"))
-            );
-            ops.add(test);
-        }
-        Translog.writeOperations(out, ops);
-        final List<Translog.Operation> readOperations = Translog.readOperations(out.bytes().streamInput(), "testSnapshotFromStreamInput");
-        assertEquals(ops.size(), readOperations.size());
-        assertEquals(ops, readOperations);
-    }
-
-    public void testSnapshotCurrentHasUnexpectedOperationsForTrimmedOperations() throws Exception {
-        int extraDocs = randomIntBetween(10, 15);
-
-        // increment primaryTerm to avoid potential negative numbers
-        primaryTerm.addAndGet(extraDocs);
-        translog.rollGeneration();
-
-        for (int op = 0; op < extraDocs; op++) {
-            String ascii = randomAlphaOfLengthBetween(1, 50);
-            Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get() - op, ascii.getBytes("UTF-8"));
-            translog.add(operation);
-        }
-
-        AssertionError error = expectThrows(AssertionError.class, () -> translog.trimOperations(primaryTerm.get(), 0));
-        assertThat(
-            error.getMessage(),
-            is(
-                "current should not have any operations with seq#:primaryTerm "
-                    + "[1:"
-                    + (primaryTerm.get() - 1)
-                    + "] > 0:"
-                    + primaryTerm.get()
-            )
-        );
-
-        primaryTerm.incrementAndGet();
-        translog.rollGeneration();
-
-        // add a single operation to current with seq# > trimmed seq# but higher primary term
-        Translog.Index operation = new Translog.Index("" + 1, 1L, primaryTerm.get(), randomAlphaOfLengthBetween(1, 50).getBytes("UTF-8"));
-        translog.add(operation);
-
-        // it is possible to trim after generation rollover
-        translog.trimOperations(primaryTerm.get(), 0);
-    }
-
-    public void testSnapshotTrimmedOperations() throws Exception {
-        final InMemoryTranslog inMemoryTranslog = new InMemoryTranslog();
-        final List<Translog.Operation> allOperations = new ArrayList<>();
-
-        for (int attempt = 0, maxAttempts = randomIntBetween(3, 10); attempt < maxAttempts; attempt++) {
-            List<Long> ops = LongStream.range(0, allOperations.size() + randomIntBetween(10, 15)).boxed().collect(Collectors.toList());
-            Randomness.shuffle(ops);
-
-            AtomicReference<String> source = new AtomicReference<>();
-            for (final long op : ops) {
-                source.set(randomAlphaOfLengthBetween(1, 50));
-
-                // have to use exactly the same source for same seq# if primaryTerm is not changed
-                if (primaryTerm.get() == translog.getCurrent().getPrimaryTerm()) {
-                    // use the latest source of op with the same seq# - therefore no break
-                    allOperations.stream()
-                        .filter(allOp -> allOp instanceof Translog.Index && allOp.seqNo() == op)
-                        .map(allOp -> ((Translog.Index) allOp).source().utf8ToString())
-                        .reduce((a, b) -> b)
-                        .ifPresent(source::set);
-                }
-
-                // use ongoing primaryTerms - or the same as it was
-                Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get(), source.get().getBytes("UTF-8"));
-                translog.add(operation);
-                inMemoryTranslog.add(operation);
-                allOperations.add(operation);
-            }
-
-            if (randomBoolean()) {
-                primaryTerm.incrementAndGet();
-                translog.rollGeneration();
-            }
-
-            long maxTrimmedSeqNo = randomInt(allOperations.size());
-
-            translog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
-            inMemoryTranslog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
-            translog.sync();
-
-            Collection<Translog.Operation> effectiveOperations = inMemoryTranslog.operations();
-
-            try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-                assertThat(snapshot, containsOperationsInAnyOrder(effectiveOperations));
-                assertThat(snapshot.totalOperations(), is(allOperations.size()));
-                assertThat(snapshot.skippedOperations(), is(allOperations.size() - effectiveOperations.size()));
-            }
-        }
-    }
-
-    /**
-     * this class mimic behaviour of original {@link Translog}
-     */
-    static class InMemoryTranslog {
-        private final Map<Long, Translog.Operation> operations = new HashMap<>();
-
-        void add(Translog.Operation operation) {
-            final Translog.Operation old = operations.put(operation.seqNo(), operation);
-            assert old == null || old.primaryTerm() <= operation.primaryTerm();
-        }
-
-        void trimOperations(long belowTerm, long aboveSeqNo) {
-            for (final Iterator<Map.Entry<Long, Translog.Operation>> it = operations.entrySet().iterator(); it.hasNext();) {
-                final Map.Entry<Long, Translog.Operation> next = it.next();
-                Translog.Operation op = next.getValue();
-                boolean drop = op.primaryTerm() < belowTerm && op.seqNo() > aboveSeqNo;
-                if (drop) {
-                    it.remove();
-                }
-            }
-        }
-
-        Collection<Translog.Operation> operations() {
-            return operations.values();
-        }
-    }
-
-    public void testRandomExceptionsOnTrimOperations() throws Exception {
-        Path tempDir = createTempDir();
-        final FailSwitch fail = new FailSwitch();
-        fail.failNever();
-        TranslogConfig config = getTranslogConfig(tempDir);
-        List<FileChannel> fileChannels = new ArrayList<>();
-        final Translog failableTLog = getFailableTranslog(
-            fail,
-            config,
-            randomBoolean(),
-            false,
-            null,
-            createTranslogDeletionPolicy(),
-            fileChannels
-        );
-
-        IOException expectedException = null;
-        int translogOperations = 0;
-        final int maxAttempts = 10;
-        for (int attempt = 0; attempt < maxAttempts; attempt++) {
-            int maxTrimmedSeqNo;
-            fail.failNever();
-            int extraTranslogOperations = randomIntBetween(10, 100);
-
-            List<Integer> ops = IntStream.range(translogOperations, translogOperations + extraTranslogOperations)
-                .boxed()
-                .collect(Collectors.toList());
-            Randomness.shuffle(ops);
-            for (int op : ops) {
-                String ascii = randomAlphaOfLengthBetween(1, 50);
-                Translog.Index operation = new Translog.Index("" + op, op, primaryTerm.get(), ascii.getBytes("UTF-8"));
-
-                failableTLog.add(operation);
-            }
-
-            translogOperations += extraTranslogOperations;
-
-            // at least one roll + inc of primary term has to be there - otherwise trim would not take place at all
-            // last attempt we have to make roll as well - otherwise could skip trimming as it has been trimmed already
-            boolean rollover = attempt == 0 || attempt == maxAttempts - 1 || randomBoolean();
-            if (rollover) {
-                primaryTerm.incrementAndGet();
-                failableTLog.rollGeneration();
-            }
-
-            maxTrimmedSeqNo = rollover ? translogOperations - randomIntBetween(4, 8) : translogOperations + 1;
-
-            // if we are so happy to reach the max attempts - fail it always`
-            fail.failRate(attempt < maxAttempts - 1 ? 25 : 100);
-            try {
-                failableTLog.trimOperations(primaryTerm.get(), maxTrimmedSeqNo);
-            } catch (IOException e) {
-                expectedException = e;
-                break;
-            }
-        }
-
-        assertThat(expectedException, is(not(nullValue())));
-        assertThat(failableTLog.getTragicException(), equalTo(expectedException));
-        assertThat(fileChannels, is(not(empty())));
-        assertThat("all file channels have to be closed", fileChannels.stream().filter(f -> f.isOpen()).findFirst().isPresent(), is(false));
-
-        assertThat(failableTLog.isOpen(), is(false));
-        final AlreadyClosedException alreadyClosedException = expectThrows(AlreadyClosedException.class, () -> failableTLog.newSnapshot());
-        assertThat(alreadyClosedException.getMessage(), is("translog is already closed"));
-
-        fail.failNever();
-
-        // check that despite of IO exception translog is not corrupted
-        try (Translog reopenedTranslog = openTranslog(config, failableTLog.getTranslogUUID())) {
-            try (Translog.Snapshot snapshot = reopenedTranslog.newSnapshot()) {
-                assertThat(snapshot.totalOperations(), greaterThan(0));
-                Translog.Operation operation;
-                for (int i = 0; (operation = snapshot.next()) != null; i++) {
-                    assertNotNull("operation " + i + " must be non-null", operation);
-                }
-            }
-        }
-    }
-
-    public void testLocationHashCodeEquals() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        List<Translog.Location> locations2 = new ArrayList<>();
-        int translogOperations = randomIntBetween(10, 100);
-        try (Translog translog2 = create(createTempDir())) {
-            for (int op = 0; op < translogOperations; op++) {
-                locations.add(
-                    translog.add(
-                        new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-                    )
-                );
-                locations2.add(
-                    translog2.add(
-                        new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-                    )
-                );
-            }
-            int iters = randomIntBetween(10, 100);
-            for (int i = 0; i < iters; i++) {
-                Translog.Location location = RandomPicks.randomFrom(random(), locations);
-                for (Translog.Location loc : locations) {
-                    if (loc == location) {
-                        assertTrue(loc.equals(location));
-                        assertEquals(loc.hashCode(), location.hashCode());
-                    } else {
-                        assertFalse(loc.equals(location));
-                    }
-                }
-                for (int j = 0; j < translogOperations; j++) {
-                    assertTrue(locations.get(j).equals(locations2.get(j)));
-                    assertEquals(locations.get(j).hashCode(), locations2.get(j).hashCode());
-                }
-            }
-        }
-    }
-
-    public void testOpenForeignTranslog() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int translogOperations = randomIntBetween(1, 10);
-        int firstUncommitted = 0;
-        for (int op = 0; op < translogOperations; op++) {
-            locations.add(
-                translog.add(new Translog.Index("" + op, op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8"))))
-            );
-            if (randomBoolean()) {
-                translog.rollGeneration();
-                translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(op);
-                translog.trimUnreferencedReaders();
-                firstUncommitted = op + 1;
-            }
-        }
-        final TranslogConfig config = translog.getConfig();
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        Translog.TranslogGeneration translogGeneration = translog.getGeneration();
-        translog.close();
-
-        final String foreignTranslog = randomRealisticUnicodeOfCodepointLengthBetween(1, translogGeneration.translogUUID.length());
-        try {
-            new Translog(
-                config,
-                foreignTranslog,
-                createTranslogDeletionPolicy(),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            );
-            fail("translog doesn't belong to this UUID");
-        } catch (TranslogCorruptedException ex) {
-
-        }
-        this.translog = new Translog(
-            config,
-            translogUUID,
-            deletionPolicy,
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            seqNo -> {}
-        );
-        try (Translog.Snapshot snapshot = this.translog.newSnapshot(randomLongBetween(0, firstUncommitted), Long.MAX_VALUE)) {
-            for (int i = firstUncommitted; i < translogOperations; i++) {
-                Translog.Operation next = snapshot.next();
-                assertNotNull("" + i, next);
-                assertEquals(Integer.parseInt(next.getSource().source.utf8ToString()), i);
-            }
-            assertNull(snapshot.next());
-        }
-    }
-
-    public void testFailOnClosedWrite() throws IOException {
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
-        translog.close();
-        try {
-            translog.add(new Translog.Index("1", 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
-            fail("closed");
-        } catch (AlreadyClosedException ex) {
-            // all is well
-        }
-    }
-
-    public void testCloseConcurrently() throws Throwable {
-        final int opsPerThread = randomIntBetween(10, 200);
-        int threadCount = 2 + randomInt(5);
-
-        logger.info("testing with [{}] threads, each doing [{}] ops", threadCount, opsPerThread);
-        final BlockingQueue<LocationOperation> writtenOperations = new ArrayBlockingQueue<>(threadCount * opsPerThread);
-
-        Thread[] threads = new Thread[threadCount];
-        final Exception[] threadExceptions = new Exception[threadCount];
-        final CountDownLatch downLatch = new CountDownLatch(1);
-        final AtomicLong seqNoGenerator = new AtomicLong();
-        for (int i = 0; i < threadCount; i++) {
-            final int threadId = i;
-            threads[i] = new TranslogThread(
-                translog,
-                downLatch,
-                opsPerThread,
-                threadId,
-                writtenOperations,
-                seqNoGenerator,
-                threadExceptions
-            );
-            threads[i].setDaemon(true);
-            threads[i].start();
-        }
-
-        downLatch.countDown();
-        translog.close();
-
-        for (int i = 0; i < threadCount; i++) {
-            if (threadExceptions[i] != null) {
-                if ((threadExceptions[i] instanceof AlreadyClosedException) == false) {
-                    throw threadExceptions[i];
-                }
-            }
-            threads[i].join(60 * 1000);
-        }
-    }
-
-    private class TranslogThread extends Thread {
-        private final CountDownLatch downLatch;
-        private final int opsPerThread;
-        private final int threadId;
-        private final Collection<LocationOperation> writtenOperations;
-        private final Exception[] threadExceptions;
-        private final Translog translog;
-        private final AtomicLong seqNoGenerator;
-
-        TranslogThread(
-            Translog translog,
-            CountDownLatch downLatch,
-            int opsPerThread,
-            int threadId,
-            Collection<LocationOperation> writtenOperations,
-            AtomicLong seqNoGenerator,
-            Exception[] threadExceptions
-        ) {
-            this.translog = translog;
-            this.downLatch = downLatch;
-            this.opsPerThread = opsPerThread;
-            this.threadId = threadId;
-            this.writtenOperations = writtenOperations;
-            this.seqNoGenerator = seqNoGenerator;
-            this.threadExceptions = threadExceptions;
-        }
-
-        @Override
-        public void run() {
-            try {
-                downLatch.await();
-                for (int opCount = 0; opCount < opsPerThread; opCount++) {
-                    Translog.Operation op;
-                    final Translog.Operation.Type type = randomFrom(Translog.Operation.Type.values());
-                    switch (type) {
-                        case CREATE:
-                        case INDEX:
-                            op = new Translog.Index(
-                                threadId + "_" + opCount,
-                                seqNoGenerator.getAndIncrement(),
-                                primaryTerm.get(),
-                                randomUnicodeOfLengthBetween(1, 20 * 1024).getBytes("UTF-8")
-                            );
-                            break;
-                        case DELETE:
-                            op = new Translog.Delete(
-                                threadId + "_" + opCount,
-                                seqNoGenerator.getAndIncrement(),
-                                primaryTerm.get(),
-                                1 + randomInt(100000)
-                            );
-                            break;
-                        case NO_OP:
-                            op = new Translog.NoOp(seqNoGenerator.getAndIncrement(), primaryTerm.get(), randomAlphaOfLength(16));
-                            break;
-                        default:
-                            throw new AssertionError("unsupported operation type [" + type + "]");
-                    }
-
-                    Translog.Location loc = add(op);
-                    writtenOperations.add(new LocationOperation(op, loc));
-                    if (rarely()) { // lets verify we can concurrently read this
-                        assertEquals(op, translog.readOperation(loc));
-                    }
-                    afterAdd();
-                }
-            } catch (Exception t) {
-                threadExceptions[threadId] = t;
-            }
-        }
-
-        protected Translog.Location add(Translog.Operation op) throws IOException {
-            return translog.add(op);
-        }
-
-        protected void afterAdd() throws IOException {}
-    }
-
-    public void testFailFlush() throws IOException {
-        Path tempDir = createTempDir();
-        final FailSwitch fail = new FailSwitch();
-        TranslogConfig config = getTranslogConfig(tempDir);
-        Translog translog = getFailableTranslog(fail, config);
-
-        List<Translog.Location> locations = new ArrayList<>();
-        int opsSynced = 0;
-        boolean failed = false;
-        while (failed == false) {
-            try {
-                locations.add(
-                    translog.add(
-                        new Translog.Index(
-                            "" + opsSynced,
-                            opsSynced,
-                            primaryTerm.get(),
-                            Integer.toString(opsSynced).getBytes(Charset.forName("UTF-8"))
-                        )
-                    )
-                );
-                translog.sync();
-                opsSynced++;
-            } catch (MockDirectoryWrapper.FakeIOException ex) {
-                failed = true;
-                assertFalse(translog.isOpen());
-            } catch (IOException ex) {
-                failed = true;
-                assertFalse(translog.isOpen());
-                assertEquals("__FAKE__ no space left on device", ex.getMessage());
-            }
-            if (randomBoolean()) {
-                fail.failAlways();
-            } else {
-                fail.failNever();
-            }
-        }
-        fail.failNever();
-        if (randomBoolean()) {
-            try {
-                locations.add(
-                    translog.add(
-                        new Translog.Index(
-                            "" + opsSynced,
-                            opsSynced,
-                            primaryTerm.get(),
-                            Integer.toString(opsSynced).getBytes(Charset.forName("UTF-8"))
-                        )
-                    )
-                );
-                fail("we are already closed");
-            } catch (AlreadyClosedException ex) {
-                assertNotNull(ex.getCause());
-                if (ex.getCause() instanceof MockDirectoryWrapper.FakeIOException) {
-                    assertNull(ex.getCause().getMessage());
-                } else {
-                    assertEquals(ex.getCause().getMessage(), "__FAKE__ no space left on device");
-                }
-            }
-
-        }
-        Translog.TranslogGeneration translogGeneration = translog.getGeneration();
-        try {
-            translog.newSnapshot();
-            fail("already closed");
-        } catch (AlreadyClosedException ex) {
-            // all is well
-            assertNotNull(ex.getCause());
-            assertSame(translog.getTragicException(), ex.getCause());
-        }
-
-        try {
-            translog.rollGeneration();
-            fail("already closed");
-        } catch (AlreadyClosedException ex) {
-            assertNotNull(ex.getCause());
-            assertSame(translog.getTragicException(), ex.getCause());
-        }
-
-        assertFalse(translog.isOpen());
-        translog.close(); // we are closed
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        try (
-            Translog tlog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            assertEquals(
-                "lastCommitted must be 1 less than current",
-                translogGeneration.translogFileGeneration + 1,
-                tlog.currentFileGeneration()
-            );
-            assertFalse(tlog.syncNeeded());
-
-            try (Translog.Snapshot snapshot = tlog.newSnapshot()) {
-                assertEquals(opsSynced, snapshot.totalOperations());
-                for (int i = 0; i < opsSynced; i++) {
-                    assertEquals(
-                        "expected operation" + i + " to be in the previous translog but wasn't",
-                        tlog.currentFileGeneration() - 1,
-                        locations.get(i).generation
-                    );
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null", next);
-                    assertEquals(i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-        }
-    }
-
-    public void testTranslogOpsCountIsCorrect() throws IOException {
-        List<Translog.Location> locations = new ArrayList<>();
-        int numOps = randomIntBetween(100, 200);
-        LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer borders regularly
-        for (int opsAdded = 0; opsAdded < numOps; opsAdded++) {
-            locations.add(
-                translog.add(
-                    new Translog.Index(
-                        "" + opsAdded,
-                        opsAdded,
-                        primaryTerm.get(),
-                        lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8"))
-                    )
-                )
-            );
-            try (Translog.Snapshot snapshot = this.translog.newSnapshot()) {
-                assertEquals(opsAdded + 1, snapshot.totalOperations());
-                for (int i = 0; i < opsAdded; i++) {
-                    assertEquals(
-                        "expected operation" + i + " to be in the current translog but wasn't",
-                        translog.currentFileGeneration(),
-                        locations.get(i).generation
-                    );
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null", next);
-                }
-            }
-        }
-    }
-
-    public void testTragicEventCanBeAnyException() throws IOException {
-        Path tempDir = createTempDir();
-        final FailSwitch fail = new FailSwitch();
-        TranslogConfig config = getTranslogConfig(tempDir);
-        Translog translog = getFailableTranslog(fail, config, false, true, null, createTranslogDeletionPolicy());
-        LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer boarders regularly
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8"))));
-        fail.failAlways();
-        try {
-            Translog.Location location = translog.add(
-                new Translog.Index("2", 1, primaryTerm.get(), lineFileDocs.nextDoc().toString().getBytes(Charset.forName("UTF-8")))
-            );
-            if (randomBoolean()) {
-                translog.ensureSynced(location);
-            } else {
-                translog.sync();
-            }
-            // TODO once we have a mock FS that can simulate we can also fail on plain sync
-            fail("WTF");
-        } catch (UnknownException ex) {
-            // w00t
-        } catch (TranslogException ex) {
-            assertTrue(ex.getCause() instanceof UnknownException);
-        }
-        assertFalse(translog.isOpen());
-        assertTrue(translog.getTragicException() instanceof UnknownException);
-    }
-
-    public void testFatalIOExceptionsWhileWritingConcurrently() throws IOException, InterruptedException {
-        Path tempDir = createTempDir();
-        final FailSwitch fail = new FailSwitch();
-
-        TranslogConfig config = getTranslogConfig(tempDir);
-        Translog translog = getFailableTranslog(fail, config);
-        final String translogUUID = translog.getTranslogUUID();
-
-        final int threadCount = randomIntBetween(1, 5);
-        Thread[] threads = new Thread[threadCount];
-        final Exception[] threadExceptions = new Exception[threadCount];
-        final CountDownLatch downLatch = new CountDownLatch(1);
-        final CountDownLatch added = new CountDownLatch(randomIntBetween(10, 100));
-        final AtomicLong seqNoGenerator = new AtomicLong();
-        List<LocationOperation> writtenOperations = Collections.synchronizedList(new ArrayList<>());
-        for (int i = 0; i < threadCount; i++) {
-            final int threadId = i;
-            threads[i] = new TranslogThread(translog, downLatch, 200, threadId, writtenOperations, seqNoGenerator, threadExceptions) {
-                @Override
-                protected Translog.Location add(Translog.Operation op) throws IOException {
-                    Translog.Location add = super.add(op);
-                    added.countDown();
-                    return add;
-                }
-
-                @Override
-                protected void afterAdd() throws IOException {
-                    if (randomBoolean()) {
-                        translog.sync();
-                    }
-                }
-            };
-            threads[i].setDaemon(true);
-            threads[i].start();
-        }
-        downLatch.countDown();
-        added.await();
-        try (Closeable ignored = translog.acquireRetentionLock()) {
-            // this holds a reference to the current tlog channel such that it's not closed
-            // if we hit a tragic event. this is important to ensure that asserts inside the Translog#add doesn't trip
-            // otherwise our assertions here are off by one sometimes.
-            fail.failAlways();
-            for (int i = 0; i < threadCount; i++) {
-                threads[i].join();
-            }
-            boolean atLeastOneFailed = false;
-            for (Throwable ex : threadExceptions) {
-                if (ex != null) {
-                    assertTrue(ex.toString(), ex instanceof IOException || ex instanceof AlreadyClosedException);
-                    atLeastOneFailed = true;
-                }
-            }
-            if (atLeastOneFailed == false) {
-                try {
-                    boolean syncNeeded = translog.syncNeeded();
-                    translog.close();
-                    assertFalse("should have failed if sync was needed", syncNeeded);
-                } catch (IOException ex) {
-                    // boom now we failed
-                }
-            }
-            Collections.sort(writtenOperations, (a, b) -> a.location.compareTo(b.location));
-            assertFalse(translog.isOpen());
-            final Checkpoint checkpoint = Checkpoint.read(config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME));
-            // drop all that haven't been synced
-            writtenOperations.removeIf(next -> checkpoint.offset < (next.location.translogLocation + next.location.size));
-            try (
-                Translog tlog = new Translog(
-                    config,
-                    translogUUID,
-                    createTranslogDeletionPolicy(),
-                    () -> SequenceNumbers.NO_OPS_PERFORMED,
-                    primaryTerm::get,
-                    seqNo -> {}
-                );
-                Translog.Snapshot snapshot = tlog.newSnapshot()
-            ) {
-                if (writtenOperations.size() != snapshot.totalOperations()) {
-                    for (int i = 0; i < threadCount; i++) {
-                        if (threadExceptions[i] != null) {
-                            logger.info("Translog exception", threadExceptions[i]);
-                        }
-                    }
-                }
-                assertEquals(writtenOperations.size(), snapshot.totalOperations());
-                for (int i = 0; i < writtenOperations.size(); i++) {
-                    assertEquals(
-                        "expected operation" + i + " to be in the previous translog but wasn't",
-                        tlog.currentFileGeneration() - 1,
-                        writtenOperations.get(i).location.generation
-                    );
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null", next);
-                    assertEquals(next, writtenOperations.get(i).operation);
-                }
-            }
-        }
-    }
-
-    /**
-     * Tests the situation where the node crashes after a translog gen was committed to lucene, but before the translog had the chance
-     * to clean up its files.
-     */
-    public void testRecoveryFromAFutureGenerationCleansUp() throws IOException {
-        int translogOperations = randomIntBetween(10, 100);
-        int op = 0;
-        for (; op < translogOperations / 2; op++) {
-            translog.add(
-                new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-            );
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-        }
-        translog.rollGeneration();
-        long localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, op);
-        for (op = translogOperations / 2; op < translogOperations; op++) {
-            translog.add(
-                new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-            );
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-        }
-        long minRetainedGen = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
-        // engine blows up, after committing the above generation
-        translog.close();
-        TranslogConfig config = translog.getConfig();
-        final TranslogDeletionPolicy deletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
-        deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
-        translog = new Translog(
-            config,
-            translog.getTranslogUUID(),
-            deletionPolicy,
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            seqNo -> {}
-        );
-        assertThat(translog.getMinFileGeneration(), equalTo(1L));
-        // no trimming done yet, just recovered
-        for (long gen = 1; gen < translog.currentFileGeneration(); gen++) {
-            assertFileIsPresent(translog, gen);
-        }
-        translog.trimUnreferencedReaders();
-        for (long gen = 1; gen < minRetainedGen; gen++) {
-            assertFileDeleted(translog, gen);
-        }
-    }
-
-    /**
-     * Tests the situation where the node crashes after a translog gen was committed to lucene, but before the translog had the chance
-     * to clean up its files.
-     */
-    public void testRecoveryFromFailureOnTrimming() throws IOException {
-        Path tempDir = createTempDir();
-        final FailSwitch fail = new FailSwitch();
-        fail.failNever();
-        final TranslogConfig config = getTranslogConfig(tempDir);
-        final long localCheckpoint;
-        final String translogUUID;
-        long minGenForRecovery = 1L;
-        try (Translog translog = getFailableTranslog(fail, config)) {
-            final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-            // disable retention so we trim things
-            deletionPolicy.setRetentionSizeInBytes(-1);
-            deletionPolicy.setRetentionAgeInMillis(-1);
-            translogUUID = translog.getTranslogUUID();
-            int translogOperations = randomIntBetween(10, 100);
-            int op = 0;
-            for (; op < translogOperations / 2; op++) {
-                translog.add(
-                    new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-                );
-                if (rarely()) {
-                    translog.rollGeneration();
-                }
-            }
-            translog.rollGeneration();
-            localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, op);
-            for (op = translogOperations / 2; op < translogOperations; op++) {
-                translog.add(
-                    new Translog.Index(Integer.toString(op), op, primaryTerm.get(), Integer.toString(op).getBytes(Charset.forName("UTF-8")))
-                );
-                if (rarely()) {
-                    translog.rollGeneration();
-                }
-            }
-            deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
-            minGenForRecovery = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
-            fail.failRandomly();
-            try {
-                translog.trimUnreferencedReaders();
-            } catch (Exception e) {
-                // expected...
-            }
-        }
-        final TranslogDeletionPolicy deletionPolicy = new DefaultTranslogDeletionPolicy(-1, -1, 0);
-        deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            // we don't know when things broke exactly
-            assertThat(translog.getMinFileGeneration(), greaterThanOrEqualTo(1L));
-            assertThat(translog.getMinFileGeneration(), lessThanOrEqualTo(minGenForRecovery));
-            assertFilePresences(translog);
-            minGenForRecovery = translog.getMinGenerationForSeqNo(localCheckpoint + 1).translogFileGeneration;
-            translog.trimUnreferencedReaders();
-            assertThat(translog.getMinFileGeneration(), equalTo(minGenForRecovery));
-            assertFilePresences(translog);
-        }
-    }
-
-    private Translog getFailableTranslog(FailSwitch fail, final TranslogConfig config) throws IOException {
-        return getFailableTranslog(fail, config, randomBoolean(), false, null, createTranslogDeletionPolicy());
-    }
-
-    private static class FailSwitch {
-        private volatile int failRate;
-        private volatile boolean onceFailedFailAlways = false;
-
-        public boolean fail() {
-            final int rnd = randomIntBetween(1, 100);
-            boolean fail = rnd <= failRate;
-            if (fail && onceFailedFailAlways) {
-                failAlways();
-            }
-            return fail;
-        }
-
-        public void failNever() {
-            failRate = 0;
-        }
-
-        public void failAlways() {
-            failRate = 100;
-        }
-
-        public void failRandomly() {
-            failRate = randomIntBetween(1, 100);
-        }
-
-        public void failRate(int rate) {
-            failRate = rate;
-        }
-
-        public void onceFailedFailAlways() {
-            onceFailedFailAlways = true;
-        }
-    }
-
-    private Translog getFailableTranslog(
-        final FailSwitch fail,
-        final TranslogConfig config,
-        final boolean partialWrites,
-        final boolean throwUnknownException,
-        String translogUUID,
-        final TranslogDeletionPolicy deletionPolicy
-    ) throws IOException {
-        return getFailableTranslog(fail, config, partialWrites, throwUnknownException, translogUUID, deletionPolicy, null);
-    }
-
-    private Translog getFailableTranslog(
-        final FailSwitch fail,
-        final TranslogConfig config,
-        final boolean partialWrites,
-        final boolean throwUnknownException,
-        String translogUUID,
-        final TranslogDeletionPolicy deletionPolicy,
-        final List<FileChannel> fileChannels
-    ) throws IOException {
-        final ChannelFactory channelFactory = (file, openOption) -> {
-            FileChannel channel = FileChannel.open(file, openOption);
-            if (fileChannels != null) {
-                fileChannels.add(channel);
-            }
-            boolean success = false;
-            try {
-                // don't do partial writes for checkpoints we rely on the fact that the bytes are written as an atomic operation
-                final boolean isCkpFile = file.getFileName().toString().endsWith(".ckp");
-                ThrowingFileChannel throwingFileChannel = new ThrowingFileChannel(
-                    fail,
-                    isCkpFile ? false : partialWrites,
-                    throwUnknownException,
-                    channel
-                );
-                success = true;
-                return throwingFileChannel;
-            } finally {
-                if (success == false) {
-                    IOUtils.closeWhileHandlingException(channel);
-                }
-            }
-        };
-        if (translogUUID == null) {
-            translogUUID = Translog.createEmptyTranslog(
-                config.getTranslogPath(),
-                SequenceNumbers.NO_OPS_PERFORMED,
-                shardId,
-                channelFactory,
-                primaryTerm.get()
-            );
-        }
-        return new Translog(config, translogUUID, deletionPolicy, () -> SequenceNumbers.NO_OPS_PERFORMED, primaryTerm::get, seqNo -> {}) {
-            @Override
-            ChannelFactory getChannelFactory() {
-                return channelFactory;
-            }
-
-            @Override
-            void deleteReaderFiles(TranslogReader reader) {
-                if (fail.fail()) {
-                    // simulate going OOM and dying just at the wrong moment.
-                    throw new RuntimeException("simulated");
-                } else {
-                    super.deleteReaderFiles(reader);
-                }
-            }
-        };
-    }
-
-    public static class ThrowingFileChannel extends FilterFileChannel {
-        private final FailSwitch fail;
-        private final boolean partialWrite;
-        private final boolean throwUnknownException;
-
-        public ThrowingFileChannel(FailSwitch fail, boolean partialWrite, boolean throwUnknownException, FileChannel delegate)
-            throws MockDirectoryWrapper.FakeIOException {
-            super(delegate);
-            this.fail = fail;
-            this.partialWrite = partialWrite;
-            this.throwUnknownException = throwUnknownException;
-            if (fail.fail()) {
-                throw new MockDirectoryWrapper.FakeIOException();
-            }
-        }
-
-        @Override
-        public int read(ByteBuffer dst) throws IOException {
-            if (fail.fail()) {
-                throw new MockDirectoryWrapper.FakeIOException();
-            }
-            return super.read(dst);
-        }
-
-        @Override
-        public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
-            if (fail.fail()) {
-                throw new MockDirectoryWrapper.FakeIOException();
-            }
-            return super.read(dsts, offset, length);
-        }
-
-        @Override
-        public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public int write(ByteBuffer src, long position) throws IOException {
-            if (fail.fail()) {
-                if (partialWrite) {
-                    if (src.hasRemaining()) {
-                        final int pos = src.position();
-                        final int limit = src.limit();
-                        src.limit(randomIntBetween(pos, limit));
-                        super.write(src, position);
-                        src.limit(limit);
-                        src.position(pos);
-                        throw new IOException("__FAKE__ no space left on device");
-                    }
-                }
-                if (throwUnknownException) {
-                    throw new UnknownException();
-                } else {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-            }
-            return super.write(src, position);
-        }
-
-        @Override
-        public int write(ByteBuffer src) throws IOException {
-            if (fail.fail()) {
-                if (partialWrite) {
-                    if (src.hasRemaining()) {
-                        final int pos = src.position();
-                        final int limit = src.limit();
-                        src.limit(randomIntBetween(pos, limit));
-                        super.write(src);
-                        src.limit(limit);
-                        src.position(pos);
-                        throw new IOException("__FAKE__ no space left on device");
-                    }
-                }
-                if (throwUnknownException) {
-                    throw new UnknownException();
-                } else {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-            }
-            return super.write(src);
-        }
-
-        @Override
-        public void force(boolean metadata) throws IOException {
-            if (fail.fail()) {
-                if (throwUnknownException) {
-                    throw new UnknownException();
-                } else {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-            }
-            super.force(metadata);
-        }
-
-        @Override
-        public long position() throws IOException {
-            if (fail.fail()) {
-                if (throwUnknownException) {
-                    throw new UnknownException();
-                } else {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-            }
-            return super.position();
-        }
-    }
-
-    private static final class UnknownException extends RuntimeException {
-
-    }
-
-    // see https://github.com/elastic/elasticsearch/issues/15754
-    public void testFailWhileCreateWriteWithRecoveredTLogs() throws IOException {
-        Path tempDir = createTempDir();
-        TranslogConfig config = getTranslogConfig(tempDir);
-        Translog translog = createTranslog(config);
-        translog.add(new Translog.Index("boom", 0, primaryTerm.get(), "boom".getBytes(Charset.forName("UTF-8"))));
-        translog.close();
-        try {
-            new Translog(
-                config,
-                translog.getTranslogUUID(),
-                createTranslogDeletionPolicy(),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            ) {
-                @Override
-                protected TranslogWriter createWriter(
-                    long fileGeneration,
-                    long initialMinTranslogGen,
-                    long initialGlobalCheckpoint,
-                    LongConsumer persistedSequenceNumberConsumer
-                ) throws IOException {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-            };
-            // if we have a LeakFS here we fail if not all resources are closed
-            fail("should have been failed");
-        } catch (MockDirectoryWrapper.FakeIOException ex) {
-            // all is well
-        }
-    }
-
-    public void testRecoverWithUnbackedNextGen() throws IOException {
-        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
-        translog.close();
-        TranslogConfig config = translog.getConfig();
-
-        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
-        Checkpoint read = Checkpoint.read(ckp);
-        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
-        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
-        try (Translog tlog = openTranslog(config, translog.getTranslogUUID()); Translog.Snapshot snapshot = tlog.newSnapshot()) {
-            assertFalse(tlog.syncNeeded());
-
-            Translog.Operation op = snapshot.next();
-            assertNotNull("operation 1 must be non-null", op);
-            assertEquals("payload mismatch for operation 1", 1, Integer.parseInt(op.getSource().source.utf8ToString()));
-
-            tlog.add(new Translog.Index("" + 1, 1, primaryTerm.get(), Integer.toString(2).getBytes(Charset.forName("UTF-8"))));
-        }
-
-        try (Translog tlog = openTranslog(config, translog.getTranslogUUID()); Translog.Snapshot snapshot = tlog.newSnapshot()) {
-            assertFalse(tlog.syncNeeded());
-
-            Translog.Operation secondOp = snapshot.next();
-            assertNotNull("operation 2 must be non-null", secondOp);
-            assertEquals("payload mismatch for operation 2", Integer.parseInt(secondOp.getSource().source.utf8ToString()), 2);
-
-            Translog.Operation firstOp = snapshot.next();
-            assertNotNull("operation 1 must be non-null", firstOp);
-            assertEquals("payload mismatch for operation 1", Integer.parseInt(firstOp.getSource().source.utf8ToString()), 1);
-        }
-    }
-
-    public void testRecoverWithUnbackedNextGenInIllegalState() throws IOException {
-        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(0).getBytes(Charset.forName("UTF-8"))));
-        translog.close();
-        TranslogConfig config = translog.getConfig();
-        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
-        Checkpoint read = Checkpoint.read(ckp);
-        // don't copy the new file
-        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
-
-        TranslogException ex = expectThrows(
-            TranslogException.class,
-            () -> new Translog(
-                config,
-                translog.getTranslogUUID(),
-                translog.getDeletionPolicy(),
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        );
-        assertEquals(ex.getMessage(), "failed to create new translog file");
-        assertEquals(ex.getCause().getClass(), FileAlreadyExistsException.class);
-    }
-
-    public void testRecoverWithUnbackedNextGenAndFutureFile() throws IOException {
-        translog.add(new Translog.Index("" + 0, 0, primaryTerm.get(), Integer.toString(0).getBytes(Charset.forName("UTF-8"))));
-        translog.close();
-        TranslogConfig config = translog.getConfig();
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-
-        Path ckp = config.getTranslogPath().resolve(Translog.CHECKPOINT_FILE_NAME);
-        Checkpoint read = Checkpoint.read(ckp);
-        Files.copy(ckp, config.getTranslogPath().resolve(Translog.getCommitCheckpointFileName(read.generation)));
-        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 1) + ".tlog"));
-        // we add N+1 and N+2 to ensure we only delete the N+1 file and never jump ahead and wipe without the right condition
-        Files.createFile(config.getTranslogPath().resolve("translog-" + (read.generation + 2) + ".tlog"));
-        try (
-            Translog tlog = new Translog(
-                config,
-                translogUUID,
-                deletionPolicy,
-                () -> SequenceNumbers.NO_OPS_PERFORMED,
-                primaryTerm::get,
-                seqNo -> {}
-            )
-        ) {
-            assertFalse(tlog.syncNeeded());
-            try (Translog.Snapshot snapshot = tlog.newSnapshot()) {
-                for (int i = 0; i < 1; i++) {
-                    Translog.Operation next = snapshot.next();
-                    assertNotNull("operation " + i + " must be non-null", next);
-                    assertEquals("payload missmatch", i, Integer.parseInt(next.getSource().source.utf8ToString()));
-                }
-            }
-            tlog.add(new Translog.Index("" + 1, 1, primaryTerm.get(), Integer.toString(1).getBytes(Charset.forName("UTF-8"))));
-        }
-
-        TranslogException ex = expectThrows(
-            TranslogException.class,
-            () -> new Translog(config, translogUUID, deletionPolicy, () -> SequenceNumbers.NO_OPS_PERFORMED, primaryTerm::get, seqNo -> {})
-        );
-        assertEquals(ex.getMessage(), "failed to create new translog file");
-        assertEquals(ex.getCause().getClass(), FileAlreadyExistsException.class);
-    }
-
-    /**
-     * This test adds operations to the translog which might randomly throw an IOException. The only thing this test verifies is
-     * that we can, after we hit an exception, open and recover the translog successfully and retrieve all successfully synced operations
-     * from the transaction log.
-     */
-    public void testWithRandomException() throws IOException {
-        final int runs = randomIntBetween(5, 10);
-        for (int run = 0; run < runs; run++) {
-            Path tempDir = createTempDir();
-            final FailSwitch fail = new FailSwitch();
-            fail.failRandomly();
-            TranslogConfig config = getTranslogConfig(tempDir);
-            final int numOps = randomIntBetween(100, 200);
-            long localCheckpointOfSafeCommit = SequenceNumbers.NO_OPS_PERFORMED;
-            List<String> syncedDocs = new ArrayList<>();
-            List<String> unsynced = new ArrayList<>();
-            if (randomBoolean()) {
-                fail.onceFailedFailAlways();
-            }
-            String generationUUID = null;
-            try {
-                boolean committing = false;
-                final Translog failableTLog = getFailableTranslog(
-                    fail,
-                    config,
-                    randomBoolean(),
-                    false,
-                    generationUUID,
-                    createTranslogDeletionPolicy()
-                );
-                try {
-                    LineFileDocs lineFileDocs = new LineFileDocs(random()); // writes pretty big docs so we cross buffer boarders regularly
-                    for (int opsAdded = 0; opsAdded < numOps; opsAdded++) {
-                        String doc = lineFileDocs.nextDoc().toString();
-                        failableTLog.add(
-                            new Translog.Index("" + opsAdded, opsAdded, primaryTerm.get(), doc.getBytes(Charset.forName("UTF-8")))
-                        );
-                        unsynced.add(doc);
-                        if (randomBoolean()) {
-                            failableTLog.sync();
-                            syncedDocs.addAll(unsynced);
-                            unsynced.clear();
-                        }
-                        if (randomFloat() < 0.1) {
-                            // we have to sync here first otherwise we don't know if the sync succeeded if the commit fails
-                            failableTLog.sync();
-                            syncedDocs.addAll(unsynced);
-                            unsynced.clear();
-                            failableTLog.rollGeneration();
-                            committing = true;
-                            failableTLog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(opsAdded);
-                            syncedDocs.clear();
-                            failableTLog.trimUnreferencedReaders();
-                            committing = false;
-                            syncedDocs.clear();
-                        }
-                    }
-                    // we survived all the randomness!!!
-                    // lets close the translog and if it succeeds we are all synced again. If we don't do this we will close
-                    // it in the finally block but miss to copy over unsynced docs to syncedDocs and fail the assertion down the road...
-                    failableTLog.close();
-                    syncedDocs.addAll(unsynced);
-                    unsynced.clear();
-                } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
-                    assertEquals(failableTLog.getTragicException(), ex);
-                } catch (IOException ex) {
-                    assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
-                    assertEquals(failableTLog.getTragicException(), ex);
-                } catch (RuntimeException ex) {
-                    assertEquals(ex.getMessage(), "simulated");
-                    assertEquals(failableTLog.getTragicException(), ex);
-                } finally {
-                    Checkpoint checkpoint = Translog.readCheckpoint(config.getTranslogPath());
-                    if (checkpoint.numOps == unsynced.size() + syncedDocs.size()) {
-                        syncedDocs.addAll(unsynced); // failed in fsync but got fully written
-                        unsynced.clear();
-                    }
-                    if (committing && checkpoint.minTranslogGeneration == checkpoint.generation) {
-                        // we were committing and blew up in one of the syncs, but they made it through
-                        syncedDocs.clear();
-                        assertThat(unsynced, empty());
-                    }
-                    generationUUID = failableTLog.getTranslogUUID();
-                    localCheckpointOfSafeCommit = failableTLog.getDeletionPolicy().getLocalCheckpointOfSafeCommit();
-                    IOUtils.closeWhileHandlingException(failableTLog);
-                }
-            } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
-                // failed - that's ok, we didn't even create it
-            } catch (IOException ex) {
-                assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
-            }
-            // now randomly open this failing tlog again just to make sure we can also recover from failing during recovery
-            if (randomBoolean()) {
-                try {
-                    TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy();
-                    deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpointOfSafeCommit);
-                    IOUtils.close(getFailableTranslog(fail, config, randomBoolean(), false, generationUUID, deletionPolicy));
-                } catch (TranslogException | MockDirectoryWrapper.FakeIOException ex) {
-                    // failed - that's ok, we didn't even create it
-                } catch (IOException ex) {
-                    assertEquals(ex.getMessage(), "__FAKE__ no space left on device");
-                }
-            }
-
-            fail.failNever(); // we don't wanna fail here but we might since we write a new checkpoint and create a new tlog file
-            TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy();
-            deletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpointOfSafeCommit);
-            if (generationUUID == null) {
-                // we never managed to successfully create a translog, make it
-                generationUUID = Translog.createEmptyTranslog(
-                    config.getTranslogPath(),
-                    SequenceNumbers.NO_OPS_PERFORMED,
-                    shardId,
-                    primaryTerm.get()
-                );
-            }
-            try (
-                Translog translog = new Translog(
-                    config,
-                    generationUUID,
-                    deletionPolicy,
-                    () -> SequenceNumbers.NO_OPS_PERFORMED,
-                    primaryTerm::get,
-                    seqNo -> {}
-                );
-                Translog.Snapshot snapshot = translog.newSnapshot(localCheckpointOfSafeCommit + 1, Long.MAX_VALUE)
-            ) {
-                assertEquals(syncedDocs.size(), snapshot.totalOperations());
-                for (int i = 0; i < syncedDocs.size(); i++) {
-                    Translog.Operation next = snapshot.next();
-                    assertEquals(syncedDocs.get(i), next.getSource().source.utf8ToString());
-                    assertNotNull("operation " + i + " must be non-null", next);
-                }
-            }
-        }
-    }
-
-    private Checkpoint randomCheckpoint() {
-        final long a = randomNonNegativeLong();
-        final long b = randomNonNegativeLong();
-        final long minSeqNo;
-        final long maxSeqNo;
-        if (a <= b) {
-            minSeqNo = a;
-            maxSeqNo = b;
-        } else {
-            minSeqNo = b;
-            maxSeqNo = a;
-        }
-        final long generation = randomNonNegativeLong();
-        return new Checkpoint(
-            randomLong(),
-            randomInt(),
-            generation,
-            minSeqNo,
-            maxSeqNo,
-            randomNonNegativeLong(),
-            randomLongBetween(1, generation),
-            maxSeqNo
-        );
-    }
-
-    public void testCheckpointOnDiskFull() throws IOException {
-        final Checkpoint checkpoint = randomCheckpoint();
-        Path tempDir = createTempDir();
-        Checkpoint.write(
-            FileChannel::open,
-            tempDir.resolve("foo.cpk"),
-            checkpoint,
-            StandardOpenOption.WRITE,
-            StandardOpenOption.CREATE_NEW
-        );
-        final Checkpoint checkpoint2 = randomCheckpoint();
-        try {
-            Checkpoint.write((p, o) -> {
-                if (randomBoolean()) {
-                    throw new MockDirectoryWrapper.FakeIOException();
-                }
-                FileChannel open = FileChannel.open(p, o);
-                FailSwitch failSwitch = new FailSwitch();
-                failSwitch.failNever(); // don't fail in the ctor
-                ThrowingFileChannel channel = new ThrowingFileChannel(failSwitch, false, false, open);
-                failSwitch.failAlways();
-                return channel;
-
-            }, tempDir.resolve("foo.cpk"), checkpoint2, StandardOpenOption.WRITE);
-            fail("should have failed earlier");
-        } catch (MockDirectoryWrapper.FakeIOException ex) {
-            // fine
-        }
-        Checkpoint read = Checkpoint.read(tempDir.resolve("foo.cpk"));
-        assertEquals(read, checkpoint);
-    }
-
-    public void testLegacyCheckpointVersion() throws IOException {
-        expectThrows(
-            TranslogCorruptedException.class,
-            IndexFormatTooOldException.class,
-            () -> Checkpoint.read(getDataPath("/org/opensearch/index/checkpoint/v2.ckp.binary"))
-        );
-    }
-
-    /**
-     * Tests that closing views after the translog is fine and we can reopen the translog
-     */
-    public void testPendingDelete() throws IOException {
-        translog.add(new Translog.Index("1", 0, primaryTerm.get(), new byte[] { 1 }));
-        translog.rollGeneration();
-        TranslogConfig config = translog.getConfig();
-        final String translogUUID = translog.getTranslogUUID();
-        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(config.getIndexSettings());
-        translog.close();
-        translog = new Translog(
-            config,
-            translogUUID,
-            deletionPolicy,
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            seqNo -> {}
-        );
-        translog.add(new Translog.Index("2", 1, primaryTerm.get(), new byte[] { 2 }));
-        translog.rollGeneration();
-        Closeable lock = translog.acquireRetentionLock();
-        translog.add(new Translog.Index("3", 2, primaryTerm.get(), new byte[] { 3 }));
-        translog.close();
-        IOUtils.close(lock);
-        translog = new Translog(
-            config,
-            translogUUID,
-            deletionPolicy,
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            seqNo -> {}
-        );
-    }
-
-    public static Translog.Location randomTranslogLocation() {
-        return new Translog.Location(randomLong(), randomLong(), randomInt());
-    }
-
-    public void testTranslogOpSerialization() throws Exception {
-        BytesReference B_1 = new BytesArray(new byte[] { 1 });
-        SeqNoFieldMapper.SequenceIDFields seqID = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
-        long randomSeqNum = randomNonNegativeLong();
-        long randomPrimaryTerm = randomBoolean() ? 0 : randomNonNegativeLong();
-        seqID.seqNo.setLongValue(randomSeqNum);
-        seqID.seqNoDocValue.setLongValue(randomSeqNum);
-        seqID.primaryTerm.setLongValue(randomPrimaryTerm);
-        Field idField = new Field("_id", Uid.encodeId("1"), IdFieldMapper.Defaults.FIELD_TYPE);
-        Field versionField = new NumericDocValuesField("_version", 1);
-        Document document = new Document();
-        document.add(new TextField("value", "test", Field.Store.YES));
-        document.add(idField);
-        document.add(versionField);
-        document.add(seqID.seqNo);
-        document.add(seqID.seqNoDocValue);
-        document.add(seqID.primaryTerm);
-        ParsedDocument doc = new ParsedDocument(versionField, seqID, "1", null, Arrays.asList(document), B_1, XContentType.JSON, null);
-
-        Engine.Index eIndex = new Engine.Index(
-            newUid(doc),
-            doc,
-            randomSeqNum,
-            randomPrimaryTerm,
-            1,
-            VersionType.INTERNAL,
-            Origin.PRIMARY,
-            0,
-            0,
-            false,
-            SequenceNumbers.UNASSIGNED_SEQ_NO,
-            0
-        );
-        Engine.IndexResult eIndexResult = new Engine.IndexResult(1, randomPrimaryTerm, randomSeqNum, true);
-        Translog.Index index = new Translog.Index(eIndex, eIndexResult);
-
-        Version wireVersion = VersionUtils.randomVersionBetween(random(), Version.CURRENT.minimumCompatibilityVersion(), Version.CURRENT);
-        BytesStreamOutput out = new BytesStreamOutput();
-        out.setVersion(wireVersion);
-        Translog.Operation.writeOperation(out, index);
-        StreamInput in = out.bytes().streamInput();
-        in.setVersion(wireVersion);
-        Translog.Index serializedIndex = (Translog.Index) Translog.Operation.readOperation(in);
-        assertEquals(index, serializedIndex);
-
-        Engine.Delete eDelete = new Engine.Delete(
-            doc.id(),
-            newUid(doc),
-            randomSeqNum,
-            randomPrimaryTerm,
-            2,
-            VersionType.INTERNAL,
-            Origin.PRIMARY,
-            0,
-            SequenceNumbers.UNASSIGNED_SEQ_NO,
-            0
-        );
-        Engine.DeleteResult eDeleteResult = new Engine.DeleteResult(2, randomPrimaryTerm, randomSeqNum, true);
-        Translog.Delete delete = new Translog.Delete(eDelete, eDeleteResult);
-
-        out = new BytesStreamOutput();
-        out.setVersion(wireVersion);
-        Translog.Operation.writeOperation(out, delete);
-        in = out.bytes().streamInput();
-        in.setVersion(wireVersion);
-        Translog.Delete serializedDelete = (Translog.Delete) Translog.Operation.readOperation(in);
-        assertEquals(delete, serializedDelete);
-    }
-
-    public void testRollGeneration() throws Exception {
-        // make sure we keep some files around
-        final boolean longRetention = randomBoolean();
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        if (longRetention) {
-            deletionPolicy.setRetentionAgeInMillis(3600 * 1000);
-        } else {
-            deletionPolicy.setRetentionAgeInMillis(-1);
-        }
-        // we control retention via time, disable size based calculations for simplicity
-        deletionPolicy.setRetentionSizeInBytes(-1);
-        final long generation = translog.currentFileGeneration();
-        final int rolls = randomIntBetween(1, 16);
-        int totalOperations = 0;
-        int seqNo = 0;
-        final List<Long> primaryTerms = new ArrayList<>();
-        primaryTerms.add(primaryTerm.get()); // We always create an empty translog.
-        primaryTerms.add(primaryTerm.get());
-        for (int i = 0; i < rolls; i++) {
-            final int operations = randomIntBetween(1, 128);
-            for (int j = 0; j < operations; j++) {
-                translog.add(new Translog.NoOp(seqNo++, primaryTerm.get(), "test"));
-                totalOperations++;
-            }
-            try (ReleasableLock ignored = translog.writeLock.acquire()) {
-                if (randomBoolean()) {
-                    primaryTerm.incrementAndGet();
-                }
-                translog.rollGeneration();
-                primaryTerms.add(primaryTerm.get());
-            }
-            assertThat(translog.currentFileGeneration(), equalTo(generation + i + 1));
-            assertThat(translog.getCurrent().getPrimaryTerm(), equalTo(primaryTerm.get()));
-            assertThat(translog.totalOperations(), equalTo(totalOperations));
-        }
-        for (int i = 0; i <= rolls; i++) {
-            assertFileIsPresent(translog, generation + i);
-            final List<Long> storedPrimaryTerms = Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
-                .map(t -> t.getPrimaryTerm())
-                .collect(Collectors.toList());
-            assertThat(storedPrimaryTerms, equalTo(primaryTerms));
-        }
-
-        final BaseTranslogReader minRetainedReader = randomFrom(
-            Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
-                .filter(r -> r.getCheckpoint().minSeqNo >= 0)
-                .collect(Collectors.toList())
-        );
-        int retainedOps = Stream.concat(translog.getReaders().stream(), Stream.of(translog.getCurrent()))
-            .filter(r -> r.getCheckpoint().generation >= minRetainedReader.generation)
-            .mapToInt(r -> r.getCheckpoint().numOps)
-            .sum();
-        deletionPolicy.setLocalCheckpointOfSafeCommit(
-            randomLongBetween(minRetainedReader.getCheckpoint().minSeqNo, minRetainedReader.getCheckpoint().maxSeqNo) - 1
-        );
-        translog.trimUnreferencedReaders();
-        assertThat(translog.currentFileGeneration(), equalTo(generation + rolls));
-        assertThat(translog.stats().getUncommittedOperations(), equalTo(retainedOps));
-        if (longRetention) {
-            for (int i = 0; i <= rolls; i++) {
-                assertFileIsPresent(translog, generation + i);
-            }
-            deletionPolicy.setRetentionAgeInMillis(randomBoolean() ? 100 : -1);
-            assertBusy(() -> {
-                translog.trimUnreferencedReaders();
-                for (long i = 0; i < minRetainedReader.generation; i++) {
-                    assertFileDeleted(translog, i);
-                }
-            });
-        } else {
-            // immediate cleanup
-            for (long i = 0; i < minRetainedReader.generation; i++) {
-                assertFileDeleted(translog, i);
-            }
-        }
-        for (long i = minRetainedReader.generation; i < generation + rolls; i++) {
-            assertFileIsPresent(translog, i);
-        }
-    }
-
-    public void testMinSeqNoBasedAPI() throws IOException {
-        final int operations = randomIntBetween(1, 512);
-        final List<Long> shuffledSeqNos = LongStream.range(0, operations).boxed().collect(Collectors.toList());
-        Randomness.shuffle(shuffledSeqNos);
-        final List<Tuple<Long, Long>> seqNos = new ArrayList<>();
-        final Map<Long, Long> terms = new HashMap<>();
-        for (final Long seqNo : shuffledSeqNos) {
-            seqNos.add(Tuple.tuple(seqNo, terms.computeIfAbsent(seqNo, k -> 0L)));
-            Long repeatingTermSeqNo = randomFrom(seqNos.stream().map(Tuple::v1).collect(Collectors.toList()));
-            seqNos.add(Tuple.tuple(repeatingTermSeqNo, terms.get(repeatingTermSeqNo)));
-        }
-
-        for (final Tuple<Long, Long> tuple : seqNos) {
-            translog.add(new Translog.NoOp(tuple.v1(), tuple.v2(), "test"));
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-        }
-
-        final Map<Long, Set<Tuple<Long, Long>>> seqNoPerGeneration = new HashMap<>();
-        final Map<Long, Integer> opCountPerGeneration = new HashMap<>();
-        // one extra roll to make sure that all ops so far are available via a reader and a translog-{gen}.ckp
-        // file in a consistent way, in order to simplify checking code.
-        translog.rollGeneration();
-        for (long seqNo = 0; seqNo < operations; seqNo++) {
-            final Set<Tuple<Long, Long>> seenSeqNos = new HashSet<>();
-            final long generation = translog.getMinGenerationForSeqNo(seqNo).translogFileGeneration;
-            int expectedSnapshotOps = 0;
-            for (long g = generation; g < translog.currentFileGeneration(); g++) {
-                if (!seqNoPerGeneration.containsKey(g)) {
-                    final Set<Tuple<Long, Long>> generationSeenSeqNos = new HashSet<>();
-                    int opCount = 0;
-                    final Checkpoint checkpoint = Checkpoint.read(translog.location().resolve(Translog.getCommitCheckpointFileName(g)));
-                    try (TranslogReader reader = translog.openReader(translog.location().resolve(Translog.getFilename(g)), checkpoint)) {
-                        TranslogSnapshot snapshot = reader.newSnapshot();
-                        Translog.Operation operation;
-                        while ((operation = snapshot.next()) != null) {
-                            generationSeenSeqNos.add(Tuple.tuple(operation.seqNo(), operation.primaryTerm()));
-                            opCount++;
-                        }
-                        assertThat(opCount, equalTo(reader.totalOperations()));
-                        assertThat(opCount, equalTo(checkpoint.numOps));
-                    }
-                    opCountPerGeneration.put(g, opCount);
-                    seqNoPerGeneration.put(g, generationSeenSeqNos);
-                }
-                final Set<Tuple<Long, Long>> generationSeqNo = seqNoPerGeneration.get(g);
-                if (generationSeqNo.stream().map(Tuple::v1).max(Long::compareTo).orElse(Long.MIN_VALUE) >= seqNo) {
-                    expectedSnapshotOps += opCountPerGeneration.get(g);
-                }
-                seenSeqNos.addAll(generationSeqNo);
-            }
-            assertThat(translog.estimateTotalOperationsFromMinSeq(seqNo), equalTo(expectedSnapshotOps));
-            int readFromSnapshot = 0;
-            try (Translog.Snapshot snapshot = translog.newSnapshot(seqNo, Long.MAX_VALUE)) {
-                assertThat(snapshot.totalOperations(), equalTo(expectedSnapshotOps));
-                Translog.Operation op;
-                while ((op = snapshot.next()) != null) {
-                    assertThat(Tuple.tuple(op.seqNo(), op.primaryTerm()), is(in(seenSeqNos)));
-                    readFromSnapshot++;
-                }
-                readFromSnapshot += snapshot.skippedOperations();
-            }
-            assertThat(readFromSnapshot, equalTo(expectedSnapshotOps));
-            final long seqNoLowerBound = seqNo;
-            final Set<Tuple<Long, Long>> expected = seqNos.stream().filter(t -> t.v1() >= seqNoLowerBound).collect(Collectors.toSet());
-            seenSeqNos.retainAll(expected);
-            assertThat(seenSeqNos, equalTo(expected));
-        }
-    }
-
-    public void testSimpleCommit() throws IOException {
-        final int operations = randomIntBetween(1, 4096);
-        long seqNo = 0;
-        for (int i = 0; i < operations; i++) {
-            translog.add(new Translog.NoOp(seqNo++, primaryTerm.get(), "test'"));
-            if (rarely()) {
-                if (rarely()) {
-                    primaryTerm.incrementAndGet();
-                }
-                translog.rollGeneration();
-            }
-        }
-        translog.getDeletionPolicy().setLocalCheckpointOfSafeCommit(randomLongBetween(0, operations));
-    }
-
-    public void testAcquiredLockIsPassedToDeletionPolicy() throws IOException {
-        final int operations = randomIntBetween(1, 4096);
-        final TranslogDeletionPolicy deletionPolicy = translog.getDeletionPolicy();
-        for (int i = 0; i < operations; i++) {
-            translog.add(new Translog.NoOp(i, 0, "test"));
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-            if (rarely()) {
-                translog.getDeletionPolicy()
-                    .setLocalCheckpointOfSafeCommit(randomLongBetween(deletionPolicy.getLocalCheckpointOfSafeCommit(), i));
-            }
-            if (frequently()) {
-                long minGen;
-                try (Closeable ignored = translog.acquireRetentionLock()) {
-                    minGen = translog.getMinFileGeneration();
-                    assertThat(deletionPolicy.getTranslogRefCount(minGen), equalTo(1L));
-                }
-                assertThat(deletionPolicy.getTranslogRefCount(minGen), equalTo(0L));
-            }
-        }
-    }
-
-    public void testReadGlobalCheckpoint() throws Exception {
-        final String translogUUID = translog.getTranslogUUID();
-        globalCheckpoint.set(randomNonNegativeLong());
-        final int operations = randomIntBetween(1, 100);
-        for (int i = 0; i < operations; i++) {
-            translog.add(new Translog.NoOp(randomNonNegativeLong(), 0, "test'"));
-            if (rarely()) {
-                translog.rollGeneration();
-            }
-        }
-        translog.rollGeneration();
-        translog.close();
-        assertThat(Translog.readGlobalCheckpoint(translogDir, translogUUID), equalTo(globalCheckpoint.get()));
-        expectThrows(TranslogCorruptedException.class, () -> Translog.readGlobalCheckpoint(translogDir, UUIDs.randomBase64UUID()));
-    }
-
-    public void testSnapshotReadOperationInReverse() throws Exception {
-        final Deque<List<Translog.Operation>> views = new ArrayDeque<>();
-        views.push(new ArrayList<>());
-        final AtomicLong seqNo = new AtomicLong();
-
-        final int generations = randomIntBetween(2, 20);
-        for (int gen = 0; gen < generations; gen++) {
-            final int operations = randomIntBetween(1, 100);
-            for (int i = 0; i < operations; i++) {
-                Translog.Index op = new Translog.Index(
-                    randomAlphaOfLength(10),
-                    seqNo.getAndIncrement(),
-                    primaryTerm.get(),
-                    new byte[] { 1 }
-                );
-                translog.add(op);
-                views.peek().add(op);
-            }
-            if (frequently()) {
-                translog.rollGeneration();
-                views.push(new ArrayList<>());
-            }
-        }
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            final List<Translog.Operation> expectedSeqNo = new ArrayList<>();
-            while (views.isEmpty() == false) {
-                expectedSeqNo.addAll(views.pop());
-            }
-            assertThat(snapshot, SnapshotMatchers.equalsTo(expectedSeqNo));
-        }
-    }
-
-    public void testSnapshotDedupOperations() throws Exception {
-        final Map<Long, Translog.Operation> latestOperations = new HashMap<>();
-        final int generations = between(2, 20);
-        for (int gen = 0; gen < generations; gen++) {
-            List<Long> batch = LongStream.rangeClosed(0, between(0, 500)).boxed().collect(Collectors.toList());
-            Randomness.shuffle(batch);
-            for (Long seqNo : batch) {
-                Translog.Index op = new Translog.Index(randomAlphaOfLength(10), seqNo, primaryTerm.get(), new byte[] { 1 });
-                translog.add(op);
-                latestOperations.put(op.seqNo(), op);
-            }
-            translog.rollGeneration();
-        }
-        try (Translog.Snapshot snapshot = translog.newSnapshot()) {
-            assertThat(snapshot, containsOperationsInAnyOrder(latestOperations.values()));
-        }
-    }
-
-    /** Make sure that it's ok to close a translog snapshot multiple times */
-    public void testCloseSnapshotTwice() throws Exception {
-        int numOps = between(0, 10);
-        for (int i = 0; i < numOps; i++) {
-            Translog.Index op = new Translog.Index(randomAlphaOfLength(10), i, primaryTerm.get(), new byte[] { 1 });
-            translog.add(op);
-            if (randomBoolean()) {
-                translog.rollGeneration();
-            }
-        }
-        for (int i = 0; i < 5; i++) {
-            Translog.Snapshot snapshot = translog.newSnapshot();
-            assertThat(snapshot, SnapshotMatchers.size(numOps));
-            snapshot.close();
-            snapshot.close();
-        }
-    }
-
-    // close method should never be called directly from Translog (the only exception is closeOnTragicEvent)
-    public void testTranslogCloseInvariant() throws IOException {
-        assumeTrue("test only works with assertions enabled", Assertions.ENABLED);
-        class MisbehavingTranslog extends Translog {
-            MisbehavingTranslog(
-                TranslogConfig config,
-                String translogUUID,
-                TranslogDeletionPolicy deletionPolicy,
-                LongSupplier globalCheckpointSupplier,
-                LongSupplier primaryTermSupplier
-            ) throws IOException {
-                super(config, translogUUID, deletionPolicy, globalCheckpointSupplier, primaryTermSupplier, seqNo -> {});
-            }
-
-            void callCloseDirectly() throws IOException {
-                close();
-            }
-
-            void callCloseUsingIOUtilsWithExceptionHandling() {
-                IOUtils.closeWhileHandlingException(this);
-            }
-
-            void callCloseUsingIOUtils() throws IOException {
-                IOUtils.close(this);
-            }
-
-            void callCloseOnTragicEvent() {
-                Exception e = new Exception("test tragic exception");
-                tragedy.setTragicException(e);
-                closeOnTragicEvent(e);
-            }
-        }
-
-        globalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        Path path = createTempDir();
-        final TranslogConfig translogConfig = getTranslogConfig(path);
-        final TranslogDeletionPolicy deletionPolicy = createTranslogDeletionPolicy(translogConfig.getIndexSettings());
-        final String translogUUID = Translog.createEmptyTranslog(path, SequenceNumbers.NO_OPS_PERFORMED, shardId, primaryTerm.get());
-        MisbehavingTranslog misbehavingTranslog = new MisbehavingTranslog(
-            translogConfig,
-            translogUUID,
-            deletionPolicy,
-            () -> globalCheckpoint.get(),
-            primaryTerm::get
-        );
-
-        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseDirectly());
-        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseUsingIOUtils());
-        expectThrows(AssertionError.class, () -> misbehavingTranslog.callCloseUsingIOUtilsWithExceptionHandling());
-        misbehavingTranslog.callCloseOnTragicEvent();
-    }
-
-    public void testMaxSeqNo() throws Exception {
-        Map<Long, Long> maxSeqNoPerGeneration = new HashMap<>();
-        for (int iterations = between(1, 10), i = 0; i < iterations; i++) {
-            long startSeqNo = randomLongBetween(0, Integer.MAX_VALUE);
-            List<Long> seqNos = LongStream.range(startSeqNo, startSeqNo + randomInt(100)).boxed().collect(Collectors.toList());
-            Randomness.shuffle(seqNos);
-            for (long seqNo : seqNos) {
-                if (frequently()) {
-                    translog.add(new Translog.Index("id", seqNo, primaryTerm.get(), new byte[] { 1 }));
-                    maxSeqNoPerGeneration.compute(
-                        translog.currentFileGeneration(),
-                        (key, existing) -> existing == null ? seqNo : Math.max(existing, seqNo)
-                    );
-                }
-            }
-            translog.rollGeneration();
-        }
-        translog.sync();
-        assertThat(
-            translog.getMaxSeqNo(),
-            equalTo(maxSeqNoPerGeneration.isEmpty() ? SequenceNumbers.NO_OPS_PERFORMED : Collections.max(maxSeqNoPerGeneration.values()))
-        );
-        long expectedMaxSeqNo = maxSeqNoPerGeneration.entrySet()
-            .stream()
-            .filter(e -> e.getKey() >= translog.getMinFileGeneration())
-            .mapToLong(e -> e.getValue())
-            .max()
-            .orElse(SequenceNumbers.NO_OPS_PERFORMED);
-        assertThat(translog.getMaxSeqNo(), equalTo(expectedMaxSeqNo));
-    }
-
-    static class SortedSnapshot implements Translog.Snapshot {
-        private final Translog.Snapshot snapshot;
-        private List<Translog.Operation> operations = null;
-
-        SortedSnapshot(Translog.Snapshot snapshot) {
-            this.snapshot = snapshot;
-        }
-
-        @Override
-        public int totalOperations() {
-            return snapshot.totalOperations();
-        }
-
-        @Override
-        public Translog.Operation next() throws IOException {
-            if (operations == null) {
-                operations = new ArrayList<>();
-                Translog.Operation op;
-                while ((op = snapshot.next()) != null) {
-                    operations.add(op);
-                }
-                operations.sort(Comparator.comparing(Translog.Operation::seqNo));
-            }
-            if (operations.isEmpty()) {
-                return null;
-            }
-            return operations.remove(0);
-        }
-
-        @Override
-        public void close() throws IOException {
-            snapshot.close();
-        }
-    }
-
-    public void testCrashDuringCheckpointCopy() throws IOException {
-        final Path path = createTempDir();
-        final AtomicBoolean failOnCopy = new AtomicBoolean();
-        final String expectedExceptionMessage = "simulated failure during copy";
-        final FilterFileSystemProvider filterFileSystemProvider = new FilterFileSystemProvider(
-            path.getFileSystem().provider().getScheme(),
-            path.getFileSystem()
-        ) {
-
-            @Override
-            public void copy(Path source, Path target, CopyOption... options) throws IOException {
-                if (failOnCopy.get() && source.toString().endsWith(Translog.CHECKPOINT_SUFFIX)) {
-                    deleteIfExists(target);
-                    Files.createFile(target);
-                    throw new IOException(expectedExceptionMessage);
-                } else {
-                    super.copy(source, target, options);
-                }
-            }
-        };
-
-        try (Translog brokenTranslog = create(filterFileSystemProvider.getPath(path.toUri()))) {
-            failOnCopy.set(true);
-            primaryTerm.incrementAndGet(); // increment primary term to force rolling generation
-            assertThat(expectThrows(IOException.class, brokenTranslog::rollGeneration).getMessage(), equalTo(expectedExceptionMessage));
-            assertFalse(brokenTranslog.isOpen());
-
-            try (
-                Translog recoveredTranslog = new Translog(
-                    getTranslogConfig(path),
-                    brokenTranslog.getTranslogUUID(),
-                    brokenTranslog.getDeletionPolicy(),
-                    () -> SequenceNumbers.NO_OPS_PERFORMED,
-                    primaryTerm::get,
-                    seqNo -> {}
-                )
-            ) {
-                recoveredTranslog.rollGeneration();
-                assertFilePresences(recoveredTranslog);
-            }
-        }
-    }
-
-    public void testSyncConcurrently() throws Exception {
-        Path path = createTempDir("translog");
-        TranslogConfig config = getTranslogConfig(path);
-        String translogUUID = Translog.createEmptyTranslog(
-            config.getTranslogPath(),
-            SequenceNumbers.NO_OPS_PERFORMED,
-            shardId,
-            primaryTerm.get()
-        );
-        Set<Long> persistedSeqNos = ConcurrentCollections.newConcurrentSet();
-        AtomicLong lastGlobalCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        LongSupplier globalCheckpointSupplier = () -> {
-            if (randomBoolean()) {
-                return lastGlobalCheckpoint.addAndGet(randomIntBetween(1, 100));
-            } else {
-                return lastGlobalCheckpoint.get();
-            }
-        };
-        try (
-            Translog translog = new Translog(
-                config,
-                translogUUID,
-                createTranslogDeletionPolicy(config.getIndexSettings()),
-                globalCheckpointSupplier,
-                primaryTerm::get,
-                persistedSeqNos::add
-            )
-        ) {
-            Thread[] threads = new Thread[between(2, 8)];
-            Phaser phaser = new Phaser(threads.length);
-            AtomicLong nextSeqNo = new AtomicLong();
-            for (int t = 0; t < threads.length; t++) {
-                threads[t] = new Thread(() -> {
-                    phaser.arriveAndAwaitAdvance();
-                    int iterations = randomIntBetween(10, 100);
-                    for (int i = 0; i < iterations; i++) {
-                        List<Translog.Operation> ops = IntStream.range(0, between(1, 10))
-                            .mapToObj(n -> new Translog.Index("1", nextSeqNo.incrementAndGet(), primaryTerm.get(), new byte[] { 1 }))
-                            .collect(Collectors.toList());
-                        try {
-                            Translog.Location location = null;
-                            for (Translog.Operation op : ops) {
-                                location = translog.add(op);
-                            }
-                            assertNotNull(location);
-                            long globalCheckpoint = lastGlobalCheckpoint.get();
-                            final boolean synced;
-                            if (randomBoolean()) {
-                                synced = translog.ensureSynced(location);
-                            } else {
-                                translog.sync();
-                                synced = true;
-                            }
-                            for (Translog.Operation op : ops) {
-                                assertThat("seq# " + op.seqNo() + " was not marked as persisted", persistedSeqNos, hasItem(op.seqNo()));
-                            }
-                            Checkpoint checkpoint = translog.getLastSyncedCheckpoint();
-                            assertThat(checkpoint.offset, greaterThanOrEqualTo(location.translogLocation));
-                            for (Translog.Operation op : ops) {
-                                assertThat(checkpoint.minSeqNo, lessThanOrEqualTo(op.seqNo()));
-                                assertThat(checkpoint.maxSeqNo, greaterThanOrEqualTo(op.seqNo()));
-                            }
-                            if (synced) {
-                                assertThat(checkpoint.globalCheckpoint, greaterThanOrEqualTo(globalCheckpoint));
-                            }
-                        } catch (Exception e) {
-                            throw new AssertionError(e);
-                        }
-                    }
-                });
-                threads[t].start();
-            }
-            for (Thread thread : threads) {
-                thread.join();
-            }
-        }
-    }
-
-    public void testEnsureNoCircularException() throws Exception {
-        final AtomicBoolean failedToSyncCheckpoint = new AtomicBoolean();
-        final ChannelFactory channelFactory = (file, openOption) -> {
-            final FileChannel channel = FileChannel.open(file, openOption);
-            return new FilterFileChannel(channel) {
-                @Override
-                public void force(boolean metaData) throws IOException {
-                    if (failedToSyncCheckpoint.get()) {
-                        throw new IOException("simulated");
-                    }
-                    super.force(metaData);
-                }
-            };
-        };
-        final TranslogConfig config = getTranslogConfig(createTempDir());
-        final String translogUUID = Translog.createEmptyTranslog(
-            config.getTranslogPath(),
-            SequenceNumbers.NO_OPS_PERFORMED,
-            shardId,
-            channelFactory,
-            primaryTerm.get()
-        );
-        final Translog translog = new Translog(
-            config,
-            translogUUID,
-            createTranslogDeletionPolicy(),
-            () -> SequenceNumbers.NO_OPS_PERFORMED,
-            primaryTerm::get,
-            seqNo -> {}
-        ) {
-            @Override
-            ChannelFactory getChannelFactory() {
-                return channelFactory;
-            }
-
-            @Override
-            void syncBeforeRollGeneration() {
-                // make it a noop like the old versions
-            }
-        };
-        try {
-            translog.add(new Translog.Index("1", 1, primaryTerm.get(), new byte[] { 1 }));
-            failedToSyncCheckpoint.set(true);
-            expectThrows(IOException.class, translog::rollGeneration);
-            final AlreadyClosedException alreadyClosedException = expectThrows(AlreadyClosedException.class, translog::rollGeneration);
-            if (hasCircularReference(alreadyClosedException)) {
-                throw new AssertionError("detect circular reference exception", alreadyClosedException);
-            }
-        } finally {
-            IOUtils.close(translog);
-        }
-    }
-
-    static boolean hasCircularReference(Exception cause) {
-        final Queue<Throwable> queue = new LinkedList<>();
-        queue.add(cause);
-        final Set<Throwable> seen = Collections.newSetFromMap(new IdentityHashMap<>());
-        while (queue.isEmpty() == false) {
-            final Throwable current = queue.remove();
-            if (seen.add(current) == false) {
-                return true;
-            }
-            Collections.addAll(queue, current.getSuppressed());
-            if (current.getCause() != null) {
-                queue.add(current.getCause());
-            }
-        }
-        return false;
-    }
-}
diff --git a/server/src/test/java/org/opensearch/index/translog/listener/TranslogListenerTests.java b/server/src/test/java/org/opensearch/index/translog/listener/TranslogListenerTests.java
new file mode 100644
index 0000000000000..dc56417ea9720
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/listener/TranslogListenerTests.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.listener;
+
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.lang.reflect.Proxy;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class TranslogListenerTests extends OpenSearchTestCase {
+
+    public void testCompositeTranslogEventListener() {
+        AtomicInteger onTranslogSyncInvoked = new AtomicInteger();
+        AtomicInteger onTranslogRecoveryInvoked = new AtomicInteger();
+        AtomicInteger onBeginTranslogRecoveryInvoked = new AtomicInteger();
+        AtomicInteger onFailureInvoked = new AtomicInteger();
+
+        TranslogEventListener listener = new TranslogEventListener() {
+            @Override
+            public void onAfterTranslogSync() {
+                onTranslogSyncInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onAfterTranslogRecovery() {
+                onTranslogRecoveryInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onBeginTranslogRecovery() {
+                onBeginTranslogRecoveryInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onFailure(String reason, Exception ex) {
+                onFailureInvoked.incrementAndGet();
+            }
+        };
+
+        final List<TranslogEventListener> translogEventListeners = new ArrayList<>(Arrays.asList(listener, listener));
+        Collections.shuffle(translogEventListeners, random());
+        TranslogEventListener compositeListener = new CompositeTranslogEventListener(
+            translogEventListeners,
+            new ShardId(new Index("indexName", "indexUuid"), 123)
+        );
+        compositeListener.onAfterTranslogRecovery();
+        compositeListener.onAfterTranslogSync();
+        compositeListener.onBeginTranslogRecovery();
+        compositeListener.onFailure("reason", new RuntimeException("reason"));
+
+        assertEquals(2, onBeginTranslogRecoveryInvoked.get());
+        assertEquals(2, onTranslogRecoveryInvoked.get());
+        assertEquals(2, onTranslogSyncInvoked.get());
+        assertEquals(2, onFailureInvoked.get());
+    }
+
+    public void testCompositeTranslogEventListenerOnExceptions() {
+        AtomicInteger onTranslogSyncInvoked = new AtomicInteger();
+        AtomicInteger onTranslogRecoveryInvoked = new AtomicInteger();
+        AtomicInteger onBeginTranslogRecoveryInvoked = new AtomicInteger();
+        AtomicInteger onFailureInvoked = new AtomicInteger();
+
+        TranslogEventListener listener = new TranslogEventListener() {
+            @Override
+            public void onAfterTranslogSync() {
+                onTranslogSyncInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onAfterTranslogRecovery() {
+                onTranslogRecoveryInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onBeginTranslogRecovery() {
+                onBeginTranslogRecoveryInvoked.incrementAndGet();
+            }
+
+            @Override
+            public void onFailure(String reason, Exception ex) {
+                onFailureInvoked.incrementAndGet();
+            }
+        };
+
+        TranslogEventListener throwingListener = (TranslogEventListener) Proxy.newProxyInstance(
+            TranslogEventListener.class.getClassLoader(),
+            new Class[] { TranslogEventListener.class },
+            (a, b, c) -> {
+                throw new RuntimeException();
+            }
+        );
+
+        final List<TranslogEventListener> translogEventListeners = new LinkedList<>(Arrays.asList(listener, throwingListener, listener));
+        Collections.shuffle(translogEventListeners, random());
+        TranslogEventListener compositeListener = new CompositeTranslogEventListener(
+            translogEventListeners,
+            new ShardId(new Index("indexName", "indexUuid"), 123)
+        );
+        expectThrows(RuntimeException.class, () -> compositeListener.onAfterTranslogRecovery());
+        expectThrows(RuntimeException.class, () -> compositeListener.onAfterTranslogSync());
+        expectThrows(RuntimeException.class, () -> compositeListener.onBeginTranslogRecovery());
+        expectThrows(RuntimeException.class, () -> compositeListener.onFailure("reason", new RuntimeException("reason")));
+
+        assertEquals(2, onBeginTranslogRecoveryInvoked.get());
+        assertEquals(2, onTranslogRecoveryInvoked.get());
+        assertEquals(2, onTranslogSyncInvoked.get());
+        assertEquals(2, onFailureInvoked.get());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceMockRepositoryTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceMockRepositoryTests.java
new file mode 100644
index 0000000000000..a806eea381297
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceMockRepositoryTests.java
@@ -0,0 +1,190 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class BlobStoreTransferServiceMockRepositoryTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+
+    private BlobStore blobStore;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        blobStore = mock(BlobStore.class);
+        threadPool = new TestThreadPool(getClass().getName());
+    }
+
+    public void testUploadBlobs() throws Exception {
+        Path testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            testFile,
+            randomNonNegativeLong(),
+            0L
+        );
+
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onResponse(null);
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        when(blobStore.blobContainer(any(BlobPath.class))).thenReturn(blobContainer);
+
+        TransferService transferService = new BlobStoreTransferService(blobStore, threadPool);
+        CountDownLatch latch = new CountDownLatch(1);
+        AtomicBoolean onResponseCalled = new AtomicBoolean(false);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        AtomicReference<FileSnapshot.TransferFileSnapshot> fileSnapshotRef = new AtomicReference<>();
+        transferService.uploadBlobs(Collections.singleton(transferFileSnapshot), new HashMap<>() {
+            {
+                put(transferFileSnapshot.getPrimaryTerm(), new BlobPath().add("sample_path"));
+            }
+        }, new LatchedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(FileSnapshot.TransferFileSnapshot fileSnapshot) {
+                onResponseCalled.set(true);
+                fileSnapshotRef.set(fileSnapshot);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionRef.set(e);
+            }
+        }, latch), WritePriority.HIGH);
+
+        assertTrue(latch.await(1000, TimeUnit.MILLISECONDS));
+        verify(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        assertTrue(onResponseCalled.get());
+        assertEquals(transferFileSnapshot.getPrimaryTerm(), fileSnapshotRef.get().getPrimaryTerm());
+        assertEquals(transferFileSnapshot.getName(), fileSnapshotRef.get().getName());
+        assertNull(exceptionRef.get());
+    }
+
+    public void testUploadBlobsIOException() throws Exception {
+        Path testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            testFile,
+            randomNonNegativeLong(),
+            0L
+        );
+
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        doThrow(new IOException()).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        when(blobStore.blobContainer(any(BlobPath.class))).thenReturn(blobContainer);
+
+        TransferService transferService = new BlobStoreTransferService(blobStore, threadPool);
+        CountDownLatch latch = new CountDownLatch(1);
+        AtomicBoolean onResponseCalled = new AtomicBoolean(false);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        transferService.uploadBlobs(Collections.singleton(transferFileSnapshot), new HashMap<>() {
+            {
+                put(transferFileSnapshot.getPrimaryTerm(), new BlobPath().add("sample_path"));
+            }
+        }, new LatchedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(FileSnapshot.TransferFileSnapshot fileSnapshot) {
+                onResponseCalled.set(true);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionRef.set(e);
+            }
+        }, latch), WritePriority.HIGH);
+
+        assertTrue(latch.await(1000, TimeUnit.MILLISECONDS));
+        verify(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        assertFalse(onResponseCalled.get());
+        assertTrue(exceptionRef.get() instanceof FileTransferException);
+    }
+
+    public void testUploadBlobsUploadFutureCompletedExceptionally() throws Exception {
+        Path testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            testFile,
+            randomNonNegativeLong(),
+            0L
+        );
+
+        AsyncMultiStreamBlobContainer blobContainer = mock(AsyncMultiStreamBlobContainer.class);
+        Mockito.doAnswer(invocation -> {
+            ActionListener<Void> completionListener = invocation.getArgument(1);
+            completionListener.onFailure(new Exception("Test exception"));
+            return null;
+        }).when(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+
+        when(blobStore.blobContainer(any(BlobPath.class))).thenReturn(blobContainer);
+
+        TransferService transferService = new BlobStoreTransferService(blobStore, threadPool);
+        CountDownLatch latch = new CountDownLatch(1);
+        AtomicBoolean onResponseCalled = new AtomicBoolean(false);
+        AtomicReference<Exception> exceptionRef = new AtomicReference<>();
+        LatchedActionListener<FileSnapshot.TransferFileSnapshot> listener = new LatchedActionListener<>(new ActionListener<>() {
+            @Override
+            public void onResponse(FileSnapshot.TransferFileSnapshot fileSnapshot) {
+                onResponseCalled.set(true);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                exceptionRef.set(e);
+            }
+        }, latch);
+        transferService.uploadBlobs(Collections.singleton(transferFileSnapshot), new HashMap<>() {
+            {
+                put(transferFileSnapshot.getPrimaryTerm(), new BlobPath().add("sample_path"));
+            }
+        }, listener, WritePriority.HIGH);
+
+        assertTrue(latch.await(1000, TimeUnit.MILLISECONDS));
+        verify(blobContainer).asyncBlobUpload(any(WriteContext.class), any());
+        assertFalse(onResponseCalled.get());
+        assertTrue(exceptionRef.get() instanceof FileTransferException);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceTests.java
new file mode 100644
index 0000000000000..e4f5a454b15f6
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/BlobStoreTransferServiceTests.java
@@ -0,0 +1,147 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.env.Environment;
+import org.opensearch.env.TestEnvironment;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class BlobStoreTransferServiceTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+
+    private BlobStoreRepository repository;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        repository = createRepository();
+        threadPool = new TestThreadPool(getClass().getName());
+    }
+
+    public void testUploadBlob() throws IOException {
+        Path testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            testFile,
+            randomNonNegativeLong(),
+            null
+        );
+        TransferService transferService = new BlobStoreTransferService(repository.blobStore(), threadPool);
+        transferService.uploadBlob(transferFileSnapshot, repository.basePath(), WritePriority.HIGH);
+    }
+
+    public void testUploadBlobFromByteArray() throws IOException {
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            "dummy_name",
+            randomByteArrayOfLength(128),
+            1
+        );
+        TransferService transferService = new BlobStoreTransferService(repository.blobStore(), threadPool);
+        transferService.uploadBlob(transferFileSnapshot, repository.basePath(), WritePriority.NORMAL);
+    }
+
+    public void testUploadBlobAsync() throws IOException, InterruptedException {
+        Path testFile = createTempFile();
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        AtomicBoolean succeeded = new AtomicBoolean(false);
+        FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+            testFile,
+            randomNonNegativeLong(),
+            null
+        );
+        CountDownLatch latch = new CountDownLatch(1);
+        TransferService transferService = new BlobStoreTransferService(repository.blobStore(), threadPool);
+        transferService.uploadBlob(
+            ThreadPool.Names.TRANSLOG_TRANSFER,
+            transferFileSnapshot,
+            repository.basePath(),
+            new LatchedActionListener<>(new ActionListener<>() {
+                @Override
+                public void onResponse(FileSnapshot.TransferFileSnapshot fileSnapshot) {
+                    assert succeeded.compareAndSet(false, true);
+                    assertEquals(transferFileSnapshot.getPrimaryTerm(), fileSnapshot.getPrimaryTerm());
+                    assertEquals(transferFileSnapshot.getName(), fileSnapshot.getName());
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    throw new AssertionError("Failed to perform uploadBlobAsync", e);
+                }
+            }, latch),
+            WritePriority.HIGH
+        );
+        assertTrue(latch.await(1000, TimeUnit.MILLISECONDS));
+        assertTrue(succeeded.get());
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        repository.stop();
+        ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
+    }
+
+    /** Create a {@link Repository} with a random name **/
+    private BlobStoreRepository createRepository() {
+        Settings settings = Settings.builder().put("location", randomAlphaOfLength(10)).build();
+        RepositoryMetadata repositoryMetadata = new RepositoryMetadata(randomAlphaOfLength(10), FsRepository.TYPE, settings);
+        final ClusterService clusterService = BlobStoreTestUtil.mockClusterService(repositoryMetadata);
+        final FsRepository repository = new FsRepository(
+            repositoryMetadata,
+            createEnvironment(),
+            xContentRegistry(),
+            clusterService,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        ) {
+            @Override
+            protected void assertSnapshotOrGenericThread() {
+                // eliminate thread name check as we create repo manually
+            }
+        };
+        clusterService.addStateApplier(event -> repository.updateState(event.state()));
+        // Apply state once to initialize repo properly like RepositoriesService would
+        repository.updateState(clusterService.state());
+        repository.start();
+        return repository;
+    }
+
+    /** Create a {@link Environment} with random path.home and path.repo **/
+    private Environment createEnvironment() {
+        Path home = createTempDir();
+        return TestEnvironment.newEnvironment(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), home.toAbsolutePath())
+                .put(Environment.PATH_REPO_SETTING.getKey(), home.resolve("repo").toAbsolutePath())
+                .build()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/FileSnapshotTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/FileSnapshotTests.java
new file mode 100644
index 0000000000000..2d75851e888a5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/FileSnapshotTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class FileSnapshotTests extends OpenSearchTestCase {
+
+    FileSnapshot fileSnapshot;
+
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        fileSnapshot.close();
+    }
+
+    public void testFileSnapshotPath() throws IOException {
+        Path file = createTempFile();
+        Files.writeString(file, "hello");
+        fileSnapshot = new FileSnapshot.TransferFileSnapshot(file, 12, null);
+
+        assertFileSnapshotProperties(file);
+
+        try (FileSnapshot sameFileSnapshot = new FileSnapshot.TransferFileSnapshot(file, 12, null)) {
+            assertEquals(sameFileSnapshot, fileSnapshot);
+        }
+
+        try (FileSnapshot sameFileDiffPTSnapshot = new FileSnapshot.TransferFileSnapshot(file, 34, null)) {
+            assertNotEquals(sameFileDiffPTSnapshot, fileSnapshot);
+        }
+    }
+
+    public void testFileSnapshotContent() throws IOException {
+        Path file = createTempFile();
+        Files.writeString(file, "hello");
+        fileSnapshot = new FileSnapshot.TransferFileSnapshot(file.getFileName().toString(), Files.readAllBytes(file), 23);
+
+        assertFileSnapshotProperties(file);
+
+        try (
+            FileSnapshot sameFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+                file.getFileName().toString(),
+                Files.readAllBytes(file),
+                23
+            )
+        ) {
+            assertEquals(sameFileSnapshot, fileSnapshot);
+        }
+
+        try (
+            FileSnapshot anotherFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+                file.getFileName().toString(),
+                Files.readAllBytes(createTempFile()),
+                23
+            )
+        ) {
+            assertNotEquals(anotherFileSnapshot, fileSnapshot);
+        }
+    }
+
+    private void assertFileSnapshotProperties(Path file) throws IOException {
+        assertEquals(file.getFileName().toString(), fileSnapshot.getName());
+        assertEquals(Files.size(file), fileSnapshot.getContentLength());
+        assertTrue(fileSnapshot.inputStream().markSupported());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/FileTransferTrackerTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/FileTransferTrackerTests.java
new file mode 100644
index 0000000000000..b96ada1f6bbff
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/FileTransferTrackerTests.java
@@ -0,0 +1,122 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class FileTransferTrackerTests extends OpenSearchTestCase {
+
+    protected final ShardId shardId = new ShardId("index", "_na_", 1);
+    FileTransferTracker fileTransferTracker;
+    RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        remoteTranslogTransferTracker = new RemoteTranslogTransferTracker(shardId, 20);
+        fileTransferTracker = new FileTransferTracker(shardId, remoteTranslogTransferTracker);
+    }
+
+    public void testOnSuccess() throws IOException {
+        Path testFile = createTempFile();
+        int fileSize = 128;
+        Files.write(testFile, randomByteArrayOfLength(128), StandardOpenOption.APPEND);
+        try (
+            FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+                testFile,
+                randomNonNegativeLong(),
+                null
+            )
+        ) {
+            Set<FileSnapshot.TransferFileSnapshot> toUpload = new HashSet<>(2);
+            toUpload.add(transferFileSnapshot);
+            fileTransferTracker.recordBytesForFiles(toUpload);
+            remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+            fileTransferTracker.onSuccess(transferFileSnapshot);
+            // idempotent
+            remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+            fileTransferTracker.onSuccess(transferFileSnapshot);
+            assertEquals(fileTransferTracker.allUploaded().size(), 1);
+            try {
+                remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+                fileTransferTracker.onFailure(transferFileSnapshot, new IOException("random exception"));
+                fail("failure after succcess invalid");
+            } catch (IllegalStateException ex) {
+                // all good
+            }
+        }
+    }
+
+    public void testOnFailure() throws IOException {
+        Path testFile = createTempFile();
+        Path testFile2 = createTempFile();
+        int fileSize = 128;
+        Files.write(testFile, randomByteArrayOfLength(fileSize), StandardOpenOption.APPEND);
+        try (
+            FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+                testFile,
+                randomNonNegativeLong(),
+                null
+            );
+            FileSnapshot.TransferFileSnapshot transferFileSnapshot2 = new FileSnapshot.TransferFileSnapshot(
+                testFile2,
+                randomNonNegativeLong(),
+                null
+            );
+        ) {
+            Set<FileSnapshot.TransferFileSnapshot> toUpload = new HashSet<>(2);
+            toUpload.add(transferFileSnapshot);
+            toUpload.add(transferFileSnapshot2);
+            fileTransferTracker.recordBytesForFiles(toUpload);
+            remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+            fileTransferTracker.onFailure(transferFileSnapshot, new IOException("random exception"));
+            fileTransferTracker.onSuccess(transferFileSnapshot2);
+            assertEquals(fileTransferTracker.allUploaded().size(), 1);
+            remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+            fileTransferTracker.onSuccess(transferFileSnapshot);
+            assertEquals(fileTransferTracker.allUploaded().size(), 2);
+        }
+    }
+
+    public void testUploaded() throws IOException {
+        Path testFile = createTempFile();
+        int fileSize = 128;
+        Files.write(testFile, randomByteArrayOfLength(fileSize), StandardOpenOption.APPEND);
+        try (
+            FileSnapshot.TransferFileSnapshot transferFileSnapshot = new FileSnapshot.TransferFileSnapshot(
+                testFile,
+                randomNonNegativeLong(),
+                null
+            );
+        ) {
+            Set<FileSnapshot.TransferFileSnapshot> toUpload = new HashSet<>(2);
+            toUpload.add(transferFileSnapshot);
+            fileTransferTracker.recordBytesForFiles(toUpload);
+            remoteTranslogTransferTracker.addUploadBytesStarted(fileSize);
+            fileTransferTracker.onSuccess(transferFileSnapshot);
+            String fileName = String.valueOf(testFile.getFileName());
+            assertTrue(fileTransferTracker.uploaded(fileName));
+            assertFalse(fileTransferTracker.uploaded("random-name"));
+
+            fileTransferTracker.delete(List.of(fileName));
+            assertFalse(fileTransferTracker.uploaded(fileName));
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferManagerTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferManagerTests.java
new file mode 100644
index 0000000000000..a48dbdcdacb71
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferManagerTests.java
@@ -0,0 +1,536 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.stream.write.WritePriority;
+import org.opensearch.common.blobstore.support.PlainBlobMetadata;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.transfer.FileSnapshot.CheckpointFileSnapshot;
+import org.opensearch.index.translog.transfer.FileSnapshot.TransferFileSnapshot;
+import org.opensearch.index.translog.transfer.FileSnapshot.TranslogFileSnapshot;
+import org.opensearch.index.translog.transfer.listener.TranslogTransferListener;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyMap;
+import static org.mockito.ArgumentMatchers.anySet;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@LuceneTestCase.SuppressFileSystems("*")
+public class TranslogTransferManagerTests extends OpenSearchTestCase {
+
+    private TransferService transferService;
+    private ShardId shardId;
+    private BlobPath remoteBaseTransferPath;
+    private ThreadPool threadPool;
+    private long primaryTerm;
+    private long generation;
+    private long minTranslogGeneration;
+    private RemoteTranslogTransferTracker remoteTranslogTransferTracker;
+    byte[] tlogBytes;
+    byte[] ckpBytes;
+    FileTransferTracker tracker;
+    TranslogTransferManager translogTransferManager;
+    long delayForBlobDownload;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        primaryTerm = randomNonNegativeLong();
+        generation = randomNonNegativeLong();
+        shardId = mock(ShardId.class);
+        when(shardId.getIndex()).thenReturn(new Index("index", "indexUUid"));
+        minTranslogGeneration = randomLongBetween(0, generation);
+        remoteBaseTransferPath = new BlobPath().add("base_path");
+        transferService = mock(TransferService.class);
+        threadPool = new TestThreadPool(getClass().getName());
+        remoteTranslogTransferTracker = new RemoteTranslogTransferTracker(shardId, 20);
+        tlogBytes = "Hello Translog".getBytes(StandardCharsets.UTF_8);
+        ckpBytes = "Hello Checkpoint".getBytes(StandardCharsets.UTF_8);
+        tracker = new FileTransferTracker(new ShardId("index", "indexUuid", 0), remoteTranslogTransferTracker);
+        translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            tracker,
+            remoteTranslogTransferTracker
+        );
+
+        delayForBlobDownload = 1;
+        when(transferService.downloadBlob(any(BlobPath.class), eq("translog-23.tlog"))).thenAnswer(invocation -> {
+            Thread.sleep(delayForBlobDownload);
+            return new ByteArrayInputStream(tlogBytes);
+        });
+
+        when(transferService.downloadBlob(any(BlobPath.class), eq("translog-23.ckp"))).thenAnswer(invocation -> {
+            Thread.sleep(delayForBlobDownload);
+            return new ByteArrayInputStream(ckpBytes);
+        });
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        terminate(threadPool);
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testTransferSnapshot() throws Exception {
+        AtomicInteger fileTransferSucceeded = new AtomicInteger();
+        AtomicInteger fileTransferFailed = new AtomicInteger();
+        AtomicInteger translogTransferSucceeded = new AtomicInteger();
+        AtomicInteger translogTransferFailed = new AtomicInteger();
+
+        doNothing().when(transferService)
+            .uploadBlob(
+                any(TransferFileSnapshot.class),
+                Mockito.eq(remoteBaseTransferPath.add(String.valueOf(primaryTerm))),
+                any(WritePriority.class)
+            );
+        doAnswer(invocationOnMock -> {
+            ActionListener<TransferFileSnapshot> listener = (ActionListener<TransferFileSnapshot>) invocationOnMock.getArguments()[2];
+            Set<TransferFileSnapshot> transferFileSnapshots = (Set<TransferFileSnapshot>) invocationOnMock.getArguments()[0];
+            transferFileSnapshots.forEach(listener::onResponse);
+            return null;
+        }).when(transferService).uploadBlobs(anySet(), anyMap(), any(ActionListener.class), any(WritePriority.class));
+
+        FileTransferTracker fileTransferTracker = new FileTransferTracker(
+            new ShardId("index", "indexUUid", 0),
+            remoteTranslogTransferTracker
+        ) {
+            @Override
+            public void onSuccess(TransferFileSnapshot fileSnapshot) {
+                fileTransferSucceeded.incrementAndGet();
+                super.onSuccess(fileSnapshot);
+            }
+
+            @Override
+            public void onFailure(TransferFileSnapshot fileSnapshot, Exception e) {
+                fileTransferFailed.incrementAndGet();
+                super.onFailure(fileSnapshot, e);
+            }
+
+        };
+
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            fileTransferTracker,
+            remoteTranslogTransferTracker
+        );
+
+        assertTrue(translogTransferManager.transferSnapshot(createTransferSnapshot(), new TranslogTransferListener() {
+            @Override
+            public void onUploadComplete(TransferSnapshot transferSnapshot) {
+                translogTransferSucceeded.incrementAndGet();
+            }
+
+            @Override
+            public void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) {
+                translogTransferFailed.incrementAndGet();
+            }
+        }));
+        assertEquals(4, fileTransferSucceeded.get());
+        assertEquals(0, fileTransferFailed.get());
+        assertEquals(1, translogTransferSucceeded.get());
+        assertEquals(0, translogTransferFailed.get());
+        assertEquals(4, fileTransferTracker.allUploaded().size());
+    }
+
+    private TransferSnapshot createTransferSnapshot() {
+        return new TransferSnapshot() {
+            @Override
+            public Set<TransferFileSnapshot> getCheckpointFileSnapshots() {
+                try {
+                    return Set.of(
+                        new CheckpointFileSnapshot(
+                            primaryTerm,
+                            generation,
+                            minTranslogGeneration,
+                            createTempFile(Translog.TRANSLOG_FILE_PREFIX + generation, Translog.CHECKPOINT_SUFFIX),
+                            null
+                        ),
+                        new CheckpointFileSnapshot(
+                            primaryTerm,
+                            generation,
+                            minTranslogGeneration,
+                            createTempFile(Translog.TRANSLOG_FILE_PREFIX + (generation - 1), Translog.CHECKPOINT_SUFFIX),
+                            null
+                        )
+                    );
+                } catch (IOException e) {
+                    throw new AssertionError("Failed to create temp file", e);
+                }
+            }
+
+            @Override
+            public Set<TransferFileSnapshot> getTranslogFileSnapshots() {
+                try {
+                    return Set.of(
+                        new TranslogFileSnapshot(
+                            primaryTerm,
+                            generation,
+                            createTempFile(Translog.TRANSLOG_FILE_PREFIX + generation, Translog.TRANSLOG_FILE_SUFFIX),
+                            null
+                        ),
+                        new TranslogFileSnapshot(
+                            primaryTerm,
+                            generation - 1,
+                            createTempFile(Translog.TRANSLOG_FILE_PREFIX + (generation - 1), Translog.TRANSLOG_FILE_SUFFIX),
+                            null
+                        )
+                    );
+                } catch (IOException e) {
+                    throw new AssertionError("Failed to create temp file", e);
+                }
+            }
+
+            @Override
+            public TranslogTransferMetadata getTranslogTransferMetadata() {
+                return new TranslogTransferMetadata(primaryTerm, generation, minTranslogGeneration, randomInt(5));
+            }
+        };
+    }
+
+    public void testReadMetadataNoFile() throws IOException {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            List<BlobMetadata> bmList = new LinkedList<>();
+            latchedActionListener.onResponse(bmList);
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrder(any(BlobPath.class), eq(TranslogTransferMetadata.METADATA_PREFIX), anyInt(), any(ActionListener.class));
+
+        assertNull(translogTransferManager.readMetadata());
+        assertNoDownloadStats(false);
+    }
+
+    // This should happen most of the time -
+    public void testReadMetadataFile() throws IOException {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+        TranslogTransferMetadata metadata1 = new TranslogTransferMetadata(1, 1, 1, 2);
+        String mdFilename1 = metadata1.getFileName();
+
+        TranslogTransferMetadata metadata2 = new TranslogTransferMetadata(1, 0, 1, 2);
+        String mdFilename2 = metadata2.getFileName();
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            List<BlobMetadata> bmList = new LinkedList<>();
+            bmList.add(new PlainBlobMetadata(mdFilename1, 1));
+            bmList.add(new PlainBlobMetadata(mdFilename2, 1));
+            latchedActionListener.onResponse(bmList);
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrder(any(BlobPath.class), eq(TranslogTransferMetadata.METADATA_PREFIX), anyInt(), any(ActionListener.class));
+
+        TranslogTransferMetadata metadata = createTransferSnapshot().getTranslogTransferMetadata();
+        long delayForMdDownload = 1;
+        when(transferService.downloadBlob(any(BlobPath.class), eq(mdFilename1))).thenAnswer(invocation -> {
+            Thread.sleep(delayForMdDownload);
+            return new ByteArrayInputStream(translogTransferManager.getMetadataBytes(metadata));
+        });
+
+        assertEquals(metadata, translogTransferManager.readMetadata());
+
+        assertEquals(translogTransferManager.getMetadataBytes(metadata).length, remoteTranslogTransferTracker.getDownloadBytesSucceeded());
+        assertTrue(remoteTranslogTransferTracker.getTotalDownloadTimeInMillis() >= delayForMdDownload);
+    }
+
+    public void testReadMetadataReadException() throws IOException {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+        TranslogTransferMetadata tm = new TranslogTransferMetadata(1, 1, 1, 2);
+        String mdFilename = tm.getFileName();
+
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            List<BlobMetadata> bmList = new LinkedList<>();
+            bmList.add(new PlainBlobMetadata(mdFilename, 1));
+            latchedActionListener.onResponse(bmList);
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrder(any(BlobPath.class), eq(TranslogTransferMetadata.METADATA_PREFIX), anyInt(), any(ActionListener.class));
+
+        when(transferService.downloadBlob(any(BlobPath.class), eq(mdFilename))).thenThrow(new IOException("Something went wrong"));
+
+        assertThrows(IOException.class, translogTransferManager::readMetadata);
+        assertNoDownloadStats(true);
+    }
+
+    public void testMetadataFileNameOrder() throws IOException {
+        // asserting that new primary followed new generation are lexicographically smallest
+        String mdFilenameGen1 = new TranslogTransferMetadata(1, 1, 1, 2).getFileName();
+        String mdFilenameGen2 = new TranslogTransferMetadata(1, 2, 1, 2).getFileName();
+        String mdFilenamePrimary2 = new TranslogTransferMetadata(2, 1, 1, 2).getFileName();
+        List<String> metadataFiles = Arrays.asList(mdFilenameGen1, mdFilenameGen2, mdFilenamePrimary2);
+        Collections.sort(metadataFiles);
+        assertEquals(Arrays.asList(mdFilenamePrimary2, mdFilenameGen2, mdFilenameGen1), metadataFiles);
+    }
+
+    public void testReadMetadataListException() throws IOException {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            latchedActionListener.onFailure(new IOException("Issue while listing"));
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrder(any(BlobPath.class), eq(TranslogTransferMetadata.METADATA_PREFIX), anyInt(), any(ActionListener.class));
+
+        when(transferService.downloadBlob(any(BlobPath.class), any(String.class))).thenThrow(new IOException("Something went wrong"));
+
+        assertThrows(IOException.class, translogTransferManager::readMetadata);
+        assertNoDownloadStats(false);
+    }
+
+    public void testDownloadTranslog() throws IOException {
+        Path location = createTempDir();
+        assertFalse(Files.exists(location.resolve("translog-23.tlog")));
+        assertFalse(Files.exists(location.resolve("translog-23.ckp")));
+        translogTransferManager.downloadTranslog("12", "23", location);
+        assertTrue(Files.exists(location.resolve("translog-23.tlog")));
+        assertTrue(Files.exists(location.resolve("translog-23.ckp")));
+        assertTlogCkpDownloadStats();
+    }
+
+    public void testDownloadTranslogAlreadyExists() throws IOException {
+        Path location = createTempDir();
+        Files.createFile(location.resolve("translog-23.tlog"));
+        Files.createFile(location.resolve("translog-23.ckp"));
+
+        translogTransferManager.downloadTranslog("12", "23", location);
+
+        verify(transferService).downloadBlob(any(BlobPath.class), eq("translog-23.tlog"));
+        verify(transferService).downloadBlob(any(BlobPath.class), eq("translog-23.ckp"));
+        assertTrue(Files.exists(location.resolve("translog-23.tlog")));
+        assertTrue(Files.exists(location.resolve("translog-23.ckp")));
+        assertTlogCkpDownloadStats();
+    }
+
+    public void testDownloadTranslogWithTrackerUpdated() throws IOException {
+        Path location = createTempDir();
+        String translogFile = "translog-23.tlog", checkpointFile = "translog-23.ckp";
+        Files.createFile(location.resolve(translogFile));
+        Files.createFile(location.resolve(checkpointFile));
+
+        translogTransferManager.downloadTranslog("12", "23", location);
+
+        verify(transferService).downloadBlob(any(BlobPath.class), eq(translogFile));
+        verify(transferService).downloadBlob(any(BlobPath.class), eq(checkpointFile));
+        assertTrue(Files.exists(location.resolve(translogFile)));
+        assertTrue(Files.exists(location.resolve(checkpointFile)));
+
+        // Since the tracker already holds the files with success state, adding them with failed state would throw exception
+        assertThrows(IllegalStateException.class, () -> tracker.add(translogFile, false));
+        assertThrows(IllegalStateException.class, () -> tracker.add(checkpointFile, false));
+
+        // Since the tracker already holds the files with success state, adding them with success state is allowed
+        tracker.add(translogFile, true);
+        tracker.add(checkpointFile, true);
+        assertTlogCkpDownloadStats();
+    }
+
+    public void testDeleteTranslogSuccess() throws Exception {
+        BlobStore blobStore = mock(BlobStore.class);
+        BlobContainer blobContainer = mock(BlobContainer.class);
+        when(blobStore.blobContainer(any(BlobPath.class))).thenReturn(blobContainer);
+        BlobStoreTransferService blobStoreTransferService = new BlobStoreTransferService(blobStore, threadPool);
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            blobStoreTransferService,
+            remoteBaseTransferPath,
+            tracker,
+            remoteTranslogTransferTracker
+        );
+        String translogFile = "translog-19.tlog", checkpointFile = "translog-19.ckp";
+        tracker.add(translogFile, true);
+        tracker.add(checkpointFile, true);
+        assertEquals(2, tracker.allUploaded().size());
+
+        List<String> files = List.of(checkpointFile, translogFile);
+        translogTransferManager.deleteGenerationAsync(primaryTerm, Set.of(19L), () -> {});
+        assertBusy(() -> assertEquals(0, tracker.allUploaded().size()));
+        verify(blobContainer).deleteBlobsIgnoringIfNotExists(eq(files));
+    }
+
+    public void testDeleteStaleTranslogMetadata() {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+        String tm1 = new TranslogTransferMetadata(1, 1, 1, 2).getFileName();
+        String tm2 = new TranslogTransferMetadata(1, 2, 1, 2).getFileName();
+        String tm3 = new TranslogTransferMetadata(2, 3, 1, 2).getFileName();
+        doAnswer(invocation -> {
+            ActionListener<List<BlobMetadata>> actionListener = invocation.getArgument(4);
+            List<BlobMetadata> bmList = new LinkedList<>();
+            bmList.add(new PlainBlobMetadata(tm1, 1));
+            bmList.add(new PlainBlobMetadata(tm2, 1));
+            bmList.add(new PlainBlobMetadata(tm3, 1));
+            actionListener.onResponse(bmList);
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrderAsync(
+                eq(ThreadPool.Names.REMOTE_PURGE),
+                any(BlobPath.class),
+                eq(TranslogTransferMetadata.METADATA_PREFIX),
+                anyInt(),
+                any(ActionListener.class)
+            );
+        List<String> files = List.of(tm2, tm3);
+        translogTransferManager.deleteStaleTranslogMetadataFilesAsync(() -> {
+            verify(transferService).listAllInSortedOrderAsync(
+                eq(ThreadPool.Names.REMOTE_PURGE),
+                any(BlobPath.class),
+                eq(TranslogTransferMetadata.METADATA_PREFIX),
+                eq(Integer.MAX_VALUE),
+                any()
+            );
+            verify(transferService).deleteBlobsAsync(
+                eq(ThreadPool.Names.REMOTE_PURGE),
+                any(BlobPath.class),
+                eq(files),
+                any(ActionListener.class)
+            );
+        });
+    }
+
+    public void testDeleteTranslogFailure() throws Exception {
+        FileTransferTracker tracker = new FileTransferTracker(new ShardId("index", "indexUuid", 0), remoteTranslogTransferTracker);
+        BlobStore blobStore = mock(BlobStore.class);
+        BlobContainer blobContainer = mock(BlobContainer.class);
+        doAnswer(invocation -> { throw new IOException("test exception"); }).when(blobStore).blobContainer(any(BlobPath.class));
+        // when(blobStore.blobContainer(any(BlobPath.class))).thenReturn(blobContainer);
+        BlobStoreTransferService blobStoreTransferService = new BlobStoreTransferService(blobStore, threadPool);
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            blobStoreTransferService,
+            remoteBaseTransferPath,
+            tracker,
+            remoteTranslogTransferTracker
+        );
+        String translogFile = "translog-19.tlog", checkpointFile = "translog-19.ckp";
+        tracker.add(translogFile, true);
+        tracker.add(checkpointFile, true);
+        assertEquals(2, tracker.allUploaded().size());
+
+        translogTransferManager.deleteGenerationAsync(primaryTerm, Set.of(19L), () -> {});
+        assertEquals(2, tracker.allUploaded().size());
+    }
+
+    private void assertNoDownloadStats(boolean nonZeroUploadTime) {
+        assertEquals(0, remoteTranslogTransferTracker.getDownloadBytesSucceeded());
+        assertEquals(0, remoteTranslogTransferTracker.getTotalDownloadsSucceeded());
+        assertEquals(0, remoteTranslogTransferTracker.getLastSuccessfulDownloadTimestamp());
+        if (nonZeroUploadTime) {
+            assertNotEquals(0, remoteTranslogTransferTracker.getTotalDownloadTimeInMillis());
+        } else {
+            assertEquals(0, remoteTranslogTransferTracker.getTotalDownloadTimeInMillis());
+        }
+    }
+
+    private void assertTlogCkpDownloadStats() {
+        assertEquals(tlogBytes.length + ckpBytes.length, remoteTranslogTransferTracker.getDownloadBytesSucceeded());
+        // Expect delay for both tlog and ckp file
+        assertTrue(remoteTranslogTransferTracker.getTotalDownloadTimeInMillis() >= 2 * delayForBlobDownload);
+    }
+
+    public void testGetPrimaryTermAndGeneration() {
+        String tm = new TranslogTransferMetadata(1, 2, 1, 2, "node-1").getFileName();
+        assertEquals(new Tuple<>(new Tuple<>(1L, 2L), "node-1"), TranslogTransferMetadata.getNodeIdByPrimaryTermAndGeneration(tm));
+    }
+
+    public void testMetadataConflict() throws InterruptedException {
+        TranslogTransferManager translogTransferManager = new TranslogTransferManager(
+            shardId,
+            transferService,
+            remoteBaseTransferPath,
+            null,
+            remoteTranslogTransferTracker
+        );
+        TranslogTransferMetadata tm = new TranslogTransferMetadata(1, 1, 1, 2, "node-1");
+        String mdFilename = tm.getFileName();
+        Thread.sleep(1);
+        TranslogTransferMetadata tm2 = new TranslogTransferMetadata(1, 1, 1, 2, "node-2");
+        String mdFilename2 = tm2.getFileName();
+
+        doAnswer(invocation -> {
+            LatchedActionListener<List<BlobMetadata>> latchedActionListener = invocation.getArgument(3);
+            List<BlobMetadata> bmList = new LinkedList<>();
+            bmList.add(new PlainBlobMetadata(mdFilename, 1));
+            bmList.add(new PlainBlobMetadata(mdFilename2, 1));
+            latchedActionListener.onResponse(bmList);
+            return null;
+        }).when(transferService)
+            .listAllInSortedOrder(any(BlobPath.class), eq(TranslogTransferMetadata.METADATA_PREFIX), anyInt(), any(ActionListener.class));
+
+        assertThrows(RuntimeException.class, translogTransferManager::readMetadata);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandlerTests.java b/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandlerTests.java
new file mode 100644
index 0000000000000..b99479df9c15e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/index/translog/transfer/TranslogTransferMetadataHandlerTests.java
@@ -0,0 +1,93 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.translog.transfer;
+
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lucene.store.ByteArrayIndexInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class TranslogTransferMetadataHandlerTests extends OpenSearchTestCase {
+    private TranslogTransferMetadataHandler handler;
+
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        handler = new TranslogTransferMetadataHandler();
+    }
+
+    public void testReadContent() throws IOException {
+        TranslogTransferMetadata expectedMetadata = getTestMetadata();
+
+        // Operation: Read expected metadata from source input stream.
+        IndexInput indexInput = new ByteArrayIndexInput("metadata file", getTestMetadataBytes());
+        TranslogTransferMetadata actualMetadata = handler.readContent(indexInput);
+
+        // Verification: Compare actual metadata read from the source input stream.
+        assertEquals(expectedMetadata, actualMetadata);
+    }
+
+    public void testWriteContent() throws IOException {
+        TranslogTransferMetadata expectedMetadata = getTestMetadata();
+
+        // Operation: Write expected metadata to the target output stream.
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput actualMetadataStream = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        handler.writeContent(actualMetadataStream, expectedMetadata);
+        actualMetadataStream.close();
+
+        // Verification: Compare actual metadata written to the target output stream.
+        IndexInput indexInput = new ByteArrayIndexInput("metadata file", BytesReference.toBytes(output.bytes()));
+        long primaryTerm = indexInput.readLong();
+        long generation = indexInput.readLong();
+        long minTranslogGeneration = indexInput.readLong();
+        Map<String, String> generationToPrimaryTermMapper = indexInput.readMapOfStrings();
+        int count = generationToPrimaryTermMapper.size();
+        TranslogTransferMetadata actualMetadata = new TranslogTransferMetadata(primaryTerm, generation, minTranslogGeneration, count);
+        actualMetadata.setGenerationToPrimaryTermMapper(generationToPrimaryTermMapper);
+        assertEquals(expectedMetadata, actualMetadata);
+    }
+
+    private TranslogTransferMetadata getTestMetadata() {
+        long primaryTerm = 3;
+        long generation = 500;
+        long minTranslogGeneration = 300;
+        Map<String, String> generationToPrimaryTermMapper = new HashMap<>();
+        generationToPrimaryTermMapper.put("300", "1");
+        generationToPrimaryTermMapper.put("400", "2");
+        generationToPrimaryTermMapper.put("500", "3");
+        int count = generationToPrimaryTermMapper.size();
+        TranslogTransferMetadata metadata = new TranslogTransferMetadata(primaryTerm, generation, minTranslogGeneration, count);
+        metadata.setGenerationToPrimaryTermMapper(generationToPrimaryTermMapper);
+
+        return metadata;
+    }
+
+    private byte[] getTestMetadataBytes() throws IOException {
+        TranslogTransferMetadata metadata = getTestMetadata();
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("dummy bytes", "dummy stream", output, 4096);
+        indexOutput.writeLong(metadata.getPrimaryTerm());
+        indexOutput.writeLong(metadata.getGeneration());
+        indexOutput.writeLong(metadata.getMinTranslogGeneration());
+        Map<String, String> generationToPrimaryTermMapper = metadata.getGenerationToPrimaryTermMapper();
+        indexOutput.writeMapOfStrings(generationToPrimaryTermMapper);
+        indexOutput.close();
+
+        return BytesReference.toBytes(output.bytes());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java b/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
index c68ad7eaba82e..c91ed00547bff 100644
--- a/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
@@ -32,13 +32,13 @@
 package org.opensearch.indices;
 
 import org.apache.lucene.search.ReferenceManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.codec.CodecService;
 import org.opensearch.index.engine.EngineConfig;
 import org.opensearch.index.engine.InternalEngine;
@@ -367,9 +367,9 @@ public void testThrottling() throws Exception {
     public void testTranslogRecoveryWorksWithIMC() throws IOException {
         IndexShard shard = newStartedShard(true);
         for (int i = 0; i < 100; i++) {
-            indexDoc(shard, Integer.toString(i), "{\"foo\" : \"bar\"}", XContentType.JSON, null);
+            indexDoc(shard, Integer.toString(i), "{\"foo\" : \"bar\"}", MediaTypeRegistry.JSON, null);
         }
-        shard.close("simon says", false);
+        shard.close("simon says", false, false);
         AtomicReference<IndexShard> shardRef = new AtomicReference<>();
         Settings settings = Settings.builder().put("indices.memory.index_buffer_size", "50kb").build();
         Iterable<IndexShard> iterable = () -> (shardRef.get() == null)
@@ -400,30 +400,29 @@ EngineConfig configWithRefreshListener(EngineConfig config, ReferenceManager.Ref
         final List<ReferenceManager.RefreshListener> internalRefreshListener = new ArrayList<>(config.getInternalRefreshListener());
         ;
         internalRefreshListener.add(listener);
-        return new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            config.getIndexSettings(),
-            config.getWarmer(),
-            config.getStore(),
-            config.getMergePolicy(),
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            config.getTranslogConfig(),
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            internalRefreshListener,
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            config.getGlobalCheckpointSupplier(),
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            config.getTombstoneDocSupplier()
-        );
+        return new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(config.getIndexSettings())
+            .warmer(config.getWarmer())
+            .store(config.getStore())
+            .mergePolicy(config.getMergePolicy())
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(config.getTranslogConfig())
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(internalRefreshListener)
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+            .build();
     }
 
     ThreadPoolStats.Stats getRefreshThreadPoolStats() {
diff --git a/server/src/test/java/org/opensearch/indices/IndicesLifecycleListenerSingleNodeTests.java b/server/src/test/java/org/opensearch/indices/IndicesLifecycleListenerSingleNodeTests.java
index 5f3d03f85f324..5e6398da6fa1b 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesLifecycleListenerSingleNodeTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesLifecycleListenerSingleNodeTests.java
@@ -39,16 +39,17 @@
 import org.opensearch.cluster.routing.ShardRoutingHelper;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.util.Arrays;
@@ -148,7 +149,13 @@ public void afterIndexRemoved(Index index, IndexSettings indexSettings, IndexRem
             newRouting = newRouting.moveToUnassigned(unassignedInfo)
                 .updateUnassigned(unassignedInfo, RecoverySource.EmptyStoreRecoverySource.INSTANCE);
             newRouting = ShardRoutingHelper.initialize(newRouting, nodeId);
-            IndexShard shard = index.createShard(newRouting, s -> {}, RetentionLeaseSyncer.EMPTY);
+            IndexShard shard = index.createShard(
+                newRouting,
+                s -> {},
+                RetentionLeaseSyncer.EMPTY,
+                SegmentReplicationCheckpointPublisher.EMPTY,
+                null
+            );
             IndexShardTestCase.updateRoutingEntry(shard, newRouting);
             assertEquals(5, counter.get());
             final DiscoveryNode localNode = new DiscoveryNode(
diff --git a/server/src/test/java/org/opensearch/indices/IndicesModuleTests.java b/server/src/test/java/org/opensearch/indices/IndicesModuleTests.java
index ef78b24be4c08..60ad6927fb506 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesModuleTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesModuleTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.indices;
 
 import org.opensearch.Version;
-import org.opensearch.index.mapper.AllFieldMapper;
 import org.opensearch.index.mapper.DataStreamFieldMapper;
+import org.opensearch.index.mapper.DocCountFieldMapper;
 import org.opensearch.index.mapper.FieldNamesFieldMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.IgnoredFieldMapper;
@@ -42,11 +42,11 @@
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.mapper.MetadataFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.RoutingFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
 import org.opensearch.index.mapper.SourceFieldMapper;
 import org.opensearch.index.mapper.TextFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.VersionFieldMapper;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.plugins.MapperPlugin;
@@ -96,32 +96,16 @@ public Map<String, MetadataFieldMapper.TypeParser> getMetadataMappers() {
         IndexFieldMapper.NAME,
         DataStreamFieldMapper.NAME,
         SourceFieldMapper.NAME,
-        TypeFieldMapper.NAME,
-        VersionFieldMapper.NAME,
-        SeqNoFieldMapper.NAME,
-        FieldNamesFieldMapper.NAME };
-
-    private static String[] EXPECTED_METADATA_FIELDS_6x = new String[] {
-        AllFieldMapper.NAME,
-        IgnoredFieldMapper.NAME,
-        IdFieldMapper.NAME,
-        RoutingFieldMapper.NAME,
-        IndexFieldMapper.NAME,
-        DataStreamFieldMapper.NAME,
-        SourceFieldMapper.NAME,
-        TypeFieldMapper.NAME,
+        NestedPathFieldMapper.NAME,
         VersionFieldMapper.NAME,
         SeqNoFieldMapper.NAME,
+        DocCountFieldMapper.NAME,
         FieldNamesFieldMapper.NAME };
 
     public void testBuiltinMappers() {
         IndicesModule module = new IndicesModule(Collections.emptyList());
         {
-            Version version = VersionUtils.randomVersionBetween(
-                random(),
-                Version.CURRENT.minimumIndexCompatibilityVersion(),
-                Version.CURRENT
-            );
+            Version version = VersionUtils.randomVersionBetween(random(), Version.V_2_0_0, Version.CURRENT);
             assertFalse(module.getMapperRegistry().getMapperParsers().isEmpty());
             assertFalse(module.getMapperRegistry().getMetadataMapperParsers(version).isEmpty());
             Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsers = module.getMapperRegistry()
@@ -132,6 +116,14 @@ public void testBuiltinMappers() {
                 assertEquals(EXPECTED_METADATA_FIELDS[i++], field);
             }
         }
+        {
+            Version version = VersionUtils.randomVersionBetween(
+                random(),
+                Version.V_1_0_0,
+                VersionUtils.getPreviousVersion(Version.V_2_0_0)
+            );
+            assertEquals(EXPECTED_METADATA_FIELDS.length - 1, module.getMapperRegistry().getMetadataMapperParsers(version).size());
+        }
     }
 
     public void testBuiltinWithPlugins() {
diff --git a/server/src/test/java/org/opensearch/indices/IndicesQueryCacheTests.java b/server/src/test/java/org/opensearch/indices/IndicesQueryCacheTests.java
index 24d8d51042548..58113f0123c8e 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesQueryCacheTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesQueryCacheTests.java
@@ -51,10 +51,10 @@
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
-import org.opensearch.core.internal.io.IOUtils;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.cache.query.QueryCacheStats;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -143,6 +143,7 @@ public void testBasics() throws IOException {
         assertEquals(0L, stats.getCacheCount());
         assertEquals(0L, stats.getHitCount());
         assertEquals(0L, stats.getMissCount());
+        assertEquals(0L, stats.getMemorySizeInBytes());
 
         assertEquals(1, s.count(new DummyQuery(0)));
 
@@ -151,6 +152,7 @@ public void testBasics() throws IOException {
         assertEquals(1L, stats.getCacheCount());
         assertEquals(0L, stats.getHitCount());
         assertEquals(1L, stats.getMissCount());
+        assertTrue(stats.getMemorySizeInBytes() > 0L && stats.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         for (int i = 1; i < 20; ++i) {
             assertEquals(1, s.count(new DummyQuery(i)));
@@ -161,6 +163,7 @@ public void testBasics() throws IOException {
         assertEquals(20L, stats.getCacheCount());
         assertEquals(0L, stats.getHitCount());
         assertEquals(20L, stats.getMissCount());
+        assertTrue(stats.getMemorySizeInBytes() > 0L && stats.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         s.count(new DummyQuery(10));
 
@@ -169,6 +172,7 @@ public void testBasics() throws IOException {
         assertEquals(20L, stats.getCacheCount());
         assertEquals(1L, stats.getHitCount());
         assertEquals(20L, stats.getMissCount());
+        assertTrue(stats.getMemorySizeInBytes() > 0L && stats.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         IOUtils.close(r, dir);
 
@@ -178,6 +182,7 @@ public void testBasics() throws IOException {
         assertEquals(20L, stats.getCacheCount());
         assertEquals(1L, stats.getHitCount());
         assertEquals(20L, stats.getMissCount());
+        assertTrue(stats.getMemorySizeInBytes() > 0L && stats.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         cache.onClose(shard);
 
@@ -187,6 +192,7 @@ public void testBasics() throws IOException {
         assertEquals(0L, stats.getCacheCount());
         assertEquals(0L, stats.getHitCount());
         assertEquals(0L, stats.getMissCount());
+        assertTrue(stats.getMemorySizeInBytes() >= 0L && stats.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         cache.close(); // this triggers some assertions
     }
@@ -227,12 +233,14 @@ public void testTwoShards() throws IOException {
         assertEquals(1L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(1L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         QueryCacheStats stats2 = cache.getStats(shard2);
         assertEquals(0L, stats2.getCacheSize());
         assertEquals(0L, stats2.getCacheCount());
         assertEquals(0L, stats2.getHitCount());
         assertEquals(0L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         assertEquals(1, s2.count(new DummyQuery(0)));
 
@@ -241,12 +249,14 @@ public void testTwoShards() throws IOException {
         assertEquals(1L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(1L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         stats2 = cache.getStats(shard2);
         assertEquals(1L, stats2.getCacheSize());
         assertEquals(1L, stats2.getCacheCount());
         assertEquals(0L, stats2.getHitCount());
         assertEquals(1L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         for (int i = 0; i < 20; ++i) {
             assertEquals(1, s2.count(new DummyQuery(i)));
@@ -257,12 +267,14 @@ public void testTwoShards() throws IOException {
         assertEquals(1L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(1L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         stats2 = cache.getStats(shard2);
         assertEquals(10L, stats2.getCacheSize());
         assertEquals(20L, stats2.getCacheCount());
         assertEquals(1L, stats2.getHitCount());
         assertEquals(20L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         IOUtils.close(r1, dir1);
 
@@ -272,12 +284,14 @@ public void testTwoShards() throws IOException {
         assertEquals(1L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(1L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         stats2 = cache.getStats(shard2);
         assertEquals(10L, stats2.getCacheSize());
         assertEquals(20L, stats2.getCacheCount());
         assertEquals(1L, stats2.getHitCount());
         assertEquals(20L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         cache.onClose(shard1);
 
@@ -287,12 +301,14 @@ public void testTwoShards() throws IOException {
         assertEquals(0L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(0L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         stats2 = cache.getStats(shard2);
         assertEquals(10L, stats2.getCacheSize());
         assertEquals(20L, stats2.getCacheCount());
         assertEquals(1L, stats2.getHitCount());
         assertEquals(20L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         IOUtils.close(r2, dir2);
         cache.onClose(shard2);
@@ -303,12 +319,14 @@ public void testTwoShards() throws IOException {
         assertEquals(0L, stats1.getCacheCount());
         assertEquals(0L, stats1.getHitCount());
         assertEquals(0L, stats1.getMissCount());
+        assertTrue(stats1.getMemorySizeInBytes() >= 0L && stats1.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         stats2 = cache.getStats(shard2);
         assertEquals(0L, stats2.getCacheSize());
         assertEquals(0L, stats2.getCacheCount());
         assertEquals(0L, stats2.getHitCount());
         assertEquals(0L, stats2.getMissCount());
+        assertTrue(stats2.getMemorySizeInBytes() >= 0L && stats2.getMemorySizeInBytes() < Long.MAX_VALUE);
 
         cache.close(); // this triggers some assertions
     }
diff --git a/server/src/test/java/org/opensearch/indices/IndicesRequestCacheTests.java b/server/src/test/java/org/opensearch/indices/IndicesRequestCacheTests.java
index 8342524b264aa..8494259c8fd8a 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesRequestCacheTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesRequestCacheTests.java
@@ -46,18 +46,18 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.bytes.AbstractBytesReference;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.bytes.AbstractBytesReference;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentHelper;
 import org.opensearch.index.cache.request.ShardRequestCache;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -75,7 +75,7 @@ public void testBasicOperationsCache() throws Exception {
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-        BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
         AtomicBoolean indexShard = new AtomicBoolean(true);
 
         // initial cache
@@ -131,7 +131,7 @@ public void testCacheDifferentReaders() throws Exception {
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-        BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
         if (randomBoolean()) {
             writer.flush();
             IOUtils.close(writer);
@@ -227,7 +227,7 @@ public void testEviction() throws Exception {
             writer.addDocument(newDoc(0, "foo"));
             DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
             TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-            BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+            BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
             TestEntity entity = new TestEntity(requestCacheStats, indexShard);
             Loader loader = new Loader(reader, 0);
 
@@ -254,7 +254,7 @@ public void testEviction() throws Exception {
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-        BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
         TestEntity entity = new TestEntity(requestCacheStats, indexShard);
         Loader loader = new Loader(reader, 0);
 
@@ -291,7 +291,7 @@ public void testClearAllEntityIdentity() throws Exception {
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-        BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
         TestEntity entity = new TestEntity(requestCacheStats, indexShard);
         Loader loader = new Loader(reader, 0);
 
@@ -353,7 +353,7 @@ public BytesReference get() {
                 IndexSearcher searcher = new IndexSearcher(reader);
                 TopDocs topDocs = searcher.search(new TermQuery(new Term("id", Integer.toString(id))), 1);
                 assertEquals(1, topDocs.totalHits.value);
-                Document document = reader.document(topDocs.scoreDocs[0].doc);
+                Document document = reader.storedFields().document(topDocs.scoreDocs[0].doc);
                 out.writeString(document.get("value"));
                 loadedFromCache = false;
                 return out.bytes();
@@ -373,7 +373,7 @@ public void testInvalidate() throws Exception {
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
-        BytesReference termBytes = XContentHelper.toXContent(termQuery, XContentType.JSON, false);
+        BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
         AtomicBoolean indexShard = new AtomicBoolean(true);
 
         // initial cache
diff --git a/server/src/test/java/org/opensearch/indices/IndicesServiceCloseTests.java b/server/src/test/java/org/opensearch/indices/IndicesServiceCloseTests.java
index e3b2afaccf054..415844dccb611 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesServiceCloseTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesServiceCloseTests.java
@@ -36,11 +36,11 @@
 import org.apache.lucene.search.Query;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.cache.RemovalNotification;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexModule;
@@ -52,10 +52,10 @@
 import org.opensearch.node.MockNode;
 import org.opensearch.node.Node;
 import org.opensearch.node.NodeValidationException;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalSettingsPlugin;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockHttpTransport;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 import org.opensearch.transport.nio.MockNioTransportPlugin;
 
diff --git a/server/src/test/java/org/opensearch/indices/IndicesServiceTests.java b/server/src/test/java/org/opensearch/indices/IndicesServiceTests.java
index 8dd156dfcd0d2..d679a3cc10ba4 100644
--- a/server/src/test/java/org/opensearch/indices/IndicesServiceTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndicesServiceTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.stats.CommonStatsFlags;
 import org.opensearch.action.admin.indices.stats.IndexShardStats;
 import org.opensearch.cluster.ClusterName;
@@ -45,16 +44,18 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLockObtainFailedException;
 import org.opensearch.gateway.GatewayMetaState;
 import org.opensearch.gateway.LocalAllocateDangledIndices;
 import org.opensearch.gateway.MetaStateService;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
@@ -66,18 +67,18 @@
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.Mapper;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.shard.IllegalIndexShardStateException;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.similarity.NonNegativeScoresSimilarity;
 import org.opensearch.indices.IndicesService.ShardDeletionCheckResult;
 import org.opensearch.plugins.EnginePlugin;
 import org.opensearch.plugins.MapperPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.hamcrest.RegexMatcher;
 
@@ -437,7 +438,7 @@ public void testDanglingIndicesWithLaterVersion() throws Exception {
         final ClusterService clusterService = getInstanceFromNode(ClusterService.class);
         final ClusterState originalState = clusterService.state();
 
-        // import an index with minor version incremented by one over cluster master version, it should be ignored
+        // import an index with minor version incremented by one over cluster cluster-manager version, it should be ignored
         final LocalAllocateDangledIndices dangling = getInstanceFromNode(LocalAllocateDangledIndices.class);
         final Settings idxSettingsLater = Settings.builder()
             .put(IndexMetadata.SETTING_VERSION_CREATED, Version.fromId(Version.CURRENT.id + 10000))
@@ -567,7 +568,13 @@ public void testIsMetadataField() {
         final Version randVersion = VersionUtils.randomIndexCompatibleVersion(random());
         assertFalse(indicesService.isMetadataField(randVersion, randomAlphaOfLengthBetween(10, 15)));
         for (String builtIn : IndicesModule.getBuiltInMetadataFields()) {
-            assertTrue(indicesService.isMetadataField(randVersion, builtIn));
+            if (NestedPathFieldMapper.NAME.equals(builtIn) && randVersion.before(Version.V_2_0_0)) {
+                continue;   // nested field mapper does not exist prior to 2.0
+            }
+            assertTrue(
+                "Expected " + builtIn + " to be a metadata field for version " + randVersion,
+                indicesService.isMetadataField(randVersion, builtIn)
+            );
         }
     }
 
@@ -621,4 +628,9 @@ public void testConflictingEngineFactories() {
             ".*multiple engine factories provided for \\[foobar/.*\\]: \\[.*FooEngineFactory\\],\\[.*BarEngineFactory\\].*";
         assertThat(e, hasToString(new RegexMatcher(pattern)));
     }
+
+    public void testClusterRemoteTranslogBufferIntervalDefault() {
+        IndicesService indicesService = getIndicesService();
+        assertEquals(IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL, indicesService.getClusterRemoteTranslogBufferInterval());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/indices/NodeIndicesStatsTests.java b/server/src/test/java/org/opensearch/indices/NodeIndicesStatsTests.java
index 40a6b6595ba25..6f36d22b7e17b 100644
--- a/server/src/test/java/org/opensearch/indices/NodeIndicesStatsTests.java
+++ b/server/src/test/java/org/opensearch/indices/NodeIndicesStatsTests.java
@@ -32,7 +32,9 @@
 
 package org.opensearch.indices;
 
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.action.admin.indices.stats.CommonStats;
+import org.opensearch.action.search.SearchRequestStats;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
@@ -43,7 +45,9 @@
 public class NodeIndicesStatsTests extends OpenSearchTestCase {
 
     public void testInvalidLevel() {
-        final NodeIndicesStats stats = new NodeIndicesStats(null, Collections.emptyMap());
+        CommonStats oldStats = new CommonStats();
+        SearchRequestStats requestStats = new SearchRequestStats();
+        final NodeIndicesStats stats = new NodeIndicesStats(oldStats, Collections.emptyMap(), requestStats);
         final String level = randomAlphaOfLength(16);
         final ToXContent.Params params = new ToXContent.MapParams(Collections.singletonMap("level", level));
         final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> stats.toXContent(null, params));
diff --git a/server/src/test/java/org/opensearch/indices/ShardLimitValidatorTests.java b/server/src/test/java/org/opensearch/indices/ShardLimitValidatorTests.java
index 7e9c971cae1e8..040632ea3ed8d 100644
--- a/server/src/test/java/org/opensearch/indices/ShardLimitValidatorTests.java
+++ b/server/src/test/java/org/opensearch/indices/ShardLimitValidatorTests.java
@@ -42,20 +42,27 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.cluster.shards.ShardCounts;
 import org.opensearch.common.ValidationException;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
 
+import static java.util.Collections.emptyMap;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.opensearch.cluster.metadata.MetadataIndexStateServiceTests.addClosedIndex;
 import static org.opensearch.cluster.metadata.MetadataIndexStateServiceTests.addOpenedIndex;
 import static org.opensearch.cluster.shards.ShardCounts.forDataNodeCount;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_CLUSTER_IGNORE_DOT_INDEXES;
 import static org.opensearch.indices.ShardLimitValidator.SETTING_CLUSTER_MAX_SHARDS_PER_NODE;
+import static org.opensearch.indices.ShardLimitValidator.SETTING_MAX_SHARDS_PER_CLUSTER_KEY;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -70,7 +77,7 @@ public void testOverShardLimit() {
         ClusterState state = createClusterForShardLimitTest(nodesInCluster, counts.getFirstIndexShards(), counts.getFirstIndexReplicas());
 
         int shardsToAdd = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
-        Optional<String> errorMessage = ShardLimitValidator.checkShardLimit(shardsToAdd, state, counts.getShardsPerNode());
+        Optional<String> errorMessage = ShardLimitValidator.checkShardLimit(shardsToAdd, state, counts.getShardsPerNode(), -1);
 
         int totalShards = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
         int currentShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
@@ -88,6 +95,36 @@ public void testOverShardLimit() {
         );
     }
 
+    public void testOverShardLimitWithMaxShardCountLimit() {
+        int nodesInCluster = randomIntBetween(1, 90);
+        ShardCounts counts = forDataNodeCount(nodesInCluster);
+
+        ClusterState state = createClusterForShardLimitTest(nodesInCluster, counts.getFirstIndexShards(), counts.getFirstIndexReplicas());
+        int shardsToAdd = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
+        int maxShardLimitOnCluster = shardsToAdd - 1;
+        Optional<String> errorMessage = ShardLimitValidator.checkShardLimit(
+            shardsToAdd,
+            state,
+            counts.getShardsPerNode(),
+            maxShardLimitOnCluster
+        );
+
+        int totalShards = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
+        int currentShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
+        int maxShards = Math.min(counts.getShardsPerNode() * nodesInCluster, maxShardLimitOnCluster);
+        assertTrue(errorMessage.isPresent());
+        assertEquals(
+            "this action would add ["
+                + totalShards
+                + "] total shards, but this cluster currently has ["
+                + currentShards
+                + "]/["
+                + maxShards
+                + "] maximum shards open",
+            errorMessage.get()
+        );
+    }
+
     public void testUnderShardLimit() {
         int nodesInCluster = randomIntBetween(2, 90);
         // Calculate the counts for a cluster 1 node smaller than we have to ensure we have headroom
@@ -99,12 +136,192 @@ public void testUnderShardLimit() {
 
         int existingShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
         int shardsToAdd = randomIntBetween(1, (counts.getShardsPerNode() * nodesInCluster) - existingShards);
-        Optional<String> errorMessage = ShardLimitValidator.checkShardLimit(shardsToAdd, state, counts.getShardsPerNode());
+        Optional<String> errorMessage = ShardLimitValidator.checkShardLimit(shardsToAdd, state, counts.getShardsPerNode(), -1);
 
         assertFalse(errorMessage.isPresent());
     }
 
-    public void testValidateShardLimit() {
+    /**
+     * This test validates that system index creation succeeds
+     * even though it exceeds the cluster max shard limit
+     */
+    public void testSystemIndexCreationSucceeds() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(1, false);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        shardLimitValidator.validateShardLimit(".tasks", settings, state);
+    }
+
+    /**
+     * This test validates that non-system index creation
+     * fails when it exceeds the cluster max shard limit
+     */
+    public void testNonSystemIndexCreationFails() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(1, false);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        final ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit("abc", settings, state)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + 2
+                + "] total shards, but this cluster currently has ["
+                + 1
+                + "]/["
+                + 1
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    public void testNonSystemIndexCreationFailsWithMaxShardLimitOnCluster() {
+        final int maxShardLimitOnCluster = 1;
+        Settings limitOnlySettings = Settings.builder()
+            .put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), 1)
+            .put(SETTING_CLUSTER_IGNORE_DOT_INDEXES.getKey(), false)
+            .put(SETTING_MAX_SHARDS_PER_CLUSTER_KEY, maxShardLimitOnCluster)
+            .build();
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(limitOnlySettings);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        final ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit("abc", settings, state)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + 2
+                + "] total shards, but this cluster currently has ["
+                + 1
+                + "]/["
+                + maxShardLimitOnCluster
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    public void testNonSystemIndexCreationPassesWithMaxShardLimitOnCluster() {
+        final int maxShardLimitOnCluster = 5;
+        Settings limitOnlySettings = Settings.builder()
+            .put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), 3)
+            .put(SETTING_CLUSTER_IGNORE_DOT_INDEXES.getKey(), false)
+            .put(SETTING_MAX_SHARDS_PER_CLUSTER_KEY, maxShardLimitOnCluster)
+            .build();
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(limitOnlySettings);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        shardLimitValidator.validateShardLimit("abc", settings, state);
+    }
+
+    /**
+     * This test validates that index starting with dot creation Succeeds
+     * when the setting cluster.ignore_dot_indexes is set to true.
+     */
+    public void testDotIndexCreationSucceeds() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(1, true);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        shardLimitValidator.validateShardLimit(".test-index", settings, state);
+    }
+
+    /**
+     * This test validates that index starting with dot creation fails
+     * when the setting cluster.ignore_dot_indexes is set to false.
+     */
+    public void testDotIndexCreationFails() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(1, false);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        final ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit(".test-index", settings, state)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + 2
+                + "] total shards, but this cluster currently has ["
+                + 1
+                + "]/["
+                + 1
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    /**
+     * This test validates that dataStream index creation fails
+     * when the cluster.ignore_dot_indexes is set to true, and we reach the max shard per node limit.
+     */
+    public void testDataStreamIndexCreationFails() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(1, true);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        final ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit(".ds-test-index", settings, state)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + 2
+                + "] total shards, but this cluster currently has ["
+                + 1
+                + "]/["
+                + 1
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    /**
+     * This test validates that dataStream index creation succeeds
+     * when the cluster.ignore_dot_indexes is set to true, and we don't reach the max shard per node limit.
+     */
+    public void testDataStreamIndexCreationSucceeds() {
+        final ShardLimitValidator shardLimitValidator = createTestShardLimitService(4, true);
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(SETTING_NUMBER_OF_SHARDS, 1)
+            .put(SETTING_NUMBER_OF_REPLICAS, 1)
+            .build();
+        final ClusterState state = createClusterForShardLimitTest(1, 1, 0);
+        shardLimitValidator.validateShardLimit(".ds-test-index", settings, state);
+    }
+
+    /**
+     * This test validates that non-system index opening
+     * fails when it exceeds the cluster max shard limit
+     */
+    public void testNonSystemIndexOpeningFails() {
         int nodesInCluster = randomIntBetween(2, 90);
         ShardCounts counts = forDataNodeCount(nodesInCluster);
         ClusterState state = createClusterForShardLimitTest(
@@ -115,7 +332,7 @@ public void testValidateShardLimit() {
             counts.getFailingIndexReplicas()
         );
 
-        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(IndexMetadata.class))
+        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(new IndexMetadata[0]))
             .map(IndexMetadata::getIndex)
             .collect(Collectors.toList())
             .toArray(new Index[2]);
@@ -123,7 +340,148 @@ public void testValidateShardLimit() {
         int totalShards = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
         int currentShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
         int maxShards = counts.getShardsPerNode() * nodesInCluster;
-        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode());
+        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode(), false);
+        ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit(state, indices)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + totalShards
+                + "] total shards, but this cluster currently has ["
+                + currentShards
+                + "]/["
+                + maxShards
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    /**
+     * This test validates that system index opening succeeds
+     * even when it exceeds the cluster max shard limit
+     */
+    public void testSystemIndexOpeningSucceeds() {
+        int nodesInCluster = randomIntBetween(2, 90);
+        ShardCounts counts = forDataNodeCount(nodesInCluster);
+        ClusterState state = createClusterForShardLimitTest(
+            nodesInCluster,
+            randomAlphaOfLengthBetween(5, 15),
+            counts.getFirstIndexShards(),
+            counts.getFirstIndexReplicas(),
+            ".tasks",               // Adding closed system index to cluster state
+            counts.getFailingIndexShards(),
+            counts.getFailingIndexReplicas()
+        );
+
+        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(new IndexMetadata[0]))
+            .map(IndexMetadata::getIndex)
+            .collect(Collectors.toList())
+            .toArray(new Index[2]);
+
+        // Shard limit validation succeeds without any issues as system index is being opened
+        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode(), false);
+        shardLimitValidator.validateShardLimit(state, indices);
+    }
+
+    /**
+     * This test validates that index having '.' in the first character
+     * opening of such indexes succeeds even when it exceeds the cluster max shard limit if the
+     * cluster.ignore_dot_indexes setting is set to true.
+     */
+    public void testDotIndexOpeningSucceeds() {
+        int nodesInCluster = randomIntBetween(2, 90);
+        ShardCounts counts = forDataNodeCount(nodesInCluster);
+        ClusterState state = createClusterForShardLimitTest(
+            nodesInCluster,
+            randomAlphaOfLengthBetween(5, 15),
+            counts.getFirstIndexShards(),
+            counts.getFirstIndexReplicas(),
+            ".test-index",               // Adding closed index starting with dot to cluster state
+            counts.getFailingIndexShards(),
+            counts.getFailingIndexReplicas()
+        );
+
+        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(new IndexMetadata[0]))
+            .map(IndexMetadata::getIndex)
+            .collect(Collectors.toList())
+            .toArray(new Index[2]);
+
+        // Shard limit validation succeeds without any issues
+        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode(), true);
+        shardLimitValidator.validateShardLimit(state, indices);
+    }
+
+    /**
+     * This test validates that index having '.' in the first character
+     * opening fails when it exceeds the cluster max shard limit if the
+     * cluster.ignore_dot_indexes is set to false.
+     */
+    public void testDotIndexOpeningFails() {
+        int nodesInCluster = randomIntBetween(2, 90);
+        ShardCounts counts = forDataNodeCount(nodesInCluster);
+        ClusterState state = createClusterForShardLimitTest(
+            nodesInCluster,
+            randomAlphaOfLengthBetween(5, 15),
+            counts.getFirstIndexShards(),
+            counts.getFirstIndexReplicas(),
+            ".test-index",               // Adding closed index starting with dot to cluster state
+            counts.getFailingIndexShards(),
+            counts.getFailingIndexReplicas()
+        );
+
+        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(new IndexMetadata[0]))
+            .map(IndexMetadata::getIndex)
+            .collect(Collectors.toList())
+            .toArray(new Index[2]);
+
+        int totalShards = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
+        int currentShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
+        int maxShards = counts.getShardsPerNode() * nodesInCluster;
+        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode(), false);
+        ValidationException exception = expectThrows(
+            ValidationException.class,
+            () -> shardLimitValidator.validateShardLimit(state, indices)
+        );
+        assertEquals(
+            "Validation Failed: 1: this action would add ["
+                + totalShards
+                + "] total shards, but this cluster currently has ["
+                + currentShards
+                + "]/["
+                + maxShards
+                + "] maximum shards open;",
+            exception.getMessage()
+        );
+    }
+
+    /**
+     * This test validates that index starting with '.ds-'
+     * opening fails when it exceeds the cluster max shard limit if the
+     * cluster.ignore_dot_indexes is set to true.
+     */
+    public void testDataStreamIndexOpeningFails() {
+        int nodesInCluster = randomIntBetween(2, 90);
+        ShardCounts counts = forDataNodeCount(nodesInCluster);
+        ClusterState state = createClusterForShardLimitTest(
+            nodesInCluster,
+            randomAlphaOfLengthBetween(5, 15),
+            counts.getFirstIndexShards(),
+            counts.getFirstIndexReplicas(),
+            ".ds-test-index",               // Adding closed data stream index to cluster state
+            counts.getFailingIndexShards(),
+            counts.getFailingIndexReplicas()
+        );
+
+        Index[] indices = Arrays.stream(state.metadata().indices().values().toArray(new IndexMetadata[0]))
+            .map(IndexMetadata::getIndex)
+            .collect(Collectors.toList())
+            .toArray(new Index[2]);
+
+        int totalShards = counts.getFailingIndexShards() * (1 + counts.getFailingIndexReplicas());
+        int currentShards = counts.getFirstIndexShards() * (1 + counts.getFirstIndexReplicas());
+        int maxShards = counts.getShardsPerNode() * nodesInCluster;
+        ShardLimitValidator shardLimitValidator = createTestShardLimitService(counts.getShardsPerNode(), true);
         ValidationException exception = expectThrows(
             ValidationException.class,
             () -> shardLimitValidator.validateShardLimit(state, indices)
@@ -141,12 +499,12 @@ public void testValidateShardLimit() {
     }
 
     public static ClusterState createClusterForShardLimitTest(int nodesInCluster, int shardsInIndex, int replicas) {
-        ImmutableOpenMap.Builder<String, DiscoveryNode> dataNodes = ImmutableOpenMap.builder();
+        final Map<String, DiscoveryNode> dataNodes = new HashMap<>();
         for (int i = 0; i < nodesInCluster; i++) {
             dataNodes.put(randomAlphaOfLengthBetween(5, 15), mock(DiscoveryNode.class));
         }
         DiscoveryNodes nodes = mock(DiscoveryNodes.class);
-        when(nodes.getDataNodes()).thenReturn(dataNodes.build());
+        when(nodes.getDataNodes()).thenReturn(dataNodes);
 
         IndexMetadata.Builder indexMetadata = IndexMetadata.builder(randomAlphaOfLengthBetween(5, 15))
             .settings(Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT))
@@ -165,21 +523,23 @@ public static ClusterState createClusterForShardLimitTest(int nodesInCluster, in
 
     public static ClusterState createClusterForShardLimitTest(
         int nodesInCluster,
+        String openIndexName,
         int openIndexShards,
         int openIndexReplicas,
+        String closeIndexName,
         int closedIndexShards,
         int closedIndexReplicas
     ) {
-        ImmutableOpenMap.Builder<String, DiscoveryNode> dataNodes = ImmutableOpenMap.builder();
+        final Map<String, DiscoveryNode> dataNodes = new HashMap<>();
         for (int i = 0; i < nodesInCluster; i++) {
             dataNodes.put(randomAlphaOfLengthBetween(5, 15), mock(DiscoveryNode.class));
         }
         DiscoveryNodes nodes = mock(DiscoveryNodes.class);
-        when(nodes.getDataNodes()).thenReturn(dataNodes.build());
+        when(nodes.getDataNodes()).thenReturn(dataNodes);
 
         ClusterState state = ClusterState.builder(ClusterName.DEFAULT).build();
-        state = addOpenedIndex(randomAlphaOfLengthBetween(5, 15), openIndexShards, openIndexReplicas, state);
-        state = addClosedIndex(randomAlphaOfLengthBetween(5, 15), closedIndexShards, closedIndexReplicas, state);
+        state = addOpenedIndex(openIndexName, openIndexShards, openIndexReplicas, state);
+        state = addClosedIndex(closeIndexName, closedIndexShards, closedIndexReplicas, state);
 
         final Metadata.Builder metadata = Metadata.builder(state.metadata());
         if (randomBoolean()) {
@@ -190,33 +550,79 @@ public static ClusterState createClusterForShardLimitTest(
         return ClusterState.builder(state).metadata(metadata).nodes(nodes).build();
     }
 
+    public static ClusterState createClusterForShardLimitTest(
+        int nodesInCluster,
+        int openIndexShards,
+        int openIndexReplicas,
+        int closedIndexShards,
+        int closedIndexReplicas
+    ) {
+        return createClusterForShardLimitTest(
+            nodesInCluster,
+            randomAlphaOfLengthBetween(5, 15),
+            openIndexShards,
+            openIndexReplicas,
+            randomAlphaOfLengthBetween(5, 15),
+            closedIndexShards,
+            closedIndexReplicas
+        );
+    }
+
+    /**
+     * Creates a {@link ShardLimitValidator} for testing with the given setting and a mocked cluster service.
+     *
+     * @param limitOnlySettings the setting used for creating ShardLimitValidator.
+     * @return a test instance
+     */
+    private static ShardLimitValidator createTestShardLimitService(final Settings limitOnlySettings) {
+        // Use a mocked clusterService - for unit tests we won't be updating the setting anyway.
+        ClusterService clusterService = mock(ClusterService.class);
+        when(clusterService.getClusterSettings()).thenReturn(
+            new ClusterSettings(limitOnlySettings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        return new ShardLimitValidator(limitOnlySettings, clusterService, new SystemIndices(emptyMap()));
+    }
+
     /**
      * Creates a {@link ShardLimitValidator} for testing with the given setting and a mocked cluster service.
      *
      * @param maxShardsPerNode the value to use for the max shards per node setting
+     * @param ignoreDotIndexes validates if index starting with dot should be ignored or not
      * @return a test instance
      */
-    public static ShardLimitValidator createTestShardLimitService(int maxShardsPerNode) {
+    public static ShardLimitValidator createTestShardLimitService(int maxShardsPerNode, boolean ignoreDotIndexes) {
         // Use a mocked clusterService - for unit tests we won't be updating the setting anyway.
         ClusterService clusterService = mock(ClusterService.class);
-        Settings limitOnlySettings = Settings.builder().put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), maxShardsPerNode).build();
+        Settings limitOnlySettings = Settings.builder()
+            .put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), maxShardsPerNode)
+            .put(SETTING_CLUSTER_IGNORE_DOT_INDEXES.getKey(), ignoreDotIndexes)
+            .build();
         when(clusterService.getClusterSettings()).thenReturn(
             new ClusterSettings(limitOnlySettings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
         );
 
-        return new ShardLimitValidator(limitOnlySettings, clusterService);
+        return new ShardLimitValidator(limitOnlySettings, clusterService, new SystemIndices(emptyMap()));
     }
 
     /**
      * Creates a {@link ShardLimitValidator} for testing with the given setting and a given cluster service.
      *
      * @param maxShardsPerNode the value to use for the max shards per node setting
+     * @param ignoreDotIndexes validates if index starting with dot should be ignored or not
      * @param clusterService   the cluster service to use
      * @return a test instance
      */
-    public static ShardLimitValidator createTestShardLimitService(int maxShardsPerNode, ClusterService clusterService) {
-        Settings limitOnlySettings = Settings.builder().put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), maxShardsPerNode).build();
+    public static ShardLimitValidator createTestShardLimitService(
+        int maxShardsPerNode,
+        boolean ignoreDotIndexes,
+        ClusterService clusterService
+    ) {
+        Settings limitOnlySettings = Settings.builder()
+            .put(SETTING_CLUSTER_MAX_SHARDS_PER_NODE.getKey(), maxShardsPerNode)
+            .put(SETTING_CLUSTER_IGNORE_DOT_INDEXES.getKey(), ignoreDotIndexes)
+            .build();
 
-        return new ShardLimitValidator(limitOnlySettings, clusterService);
+        return new ShardLimitValidator(limitOnlySettings, clusterService, new SystemIndices(emptyMap()));
     }
 }
diff --git a/server/src/test/java/org/opensearch/indices/TermsLookupTests.java b/server/src/test/java/org/opensearch/indices/TermsLookupTests.java
index 661995a22c507..8a7867729f2c1 100644
--- a/server/src/test/java/org/opensearch/indices/TermsLookupTests.java
+++ b/server/src/test/java/org/opensearch/indices/TermsLookupTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.indices;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/indices/analysis/AnalysisModuleTests.java b/server/src/test/java/org/opensearch/indices/analysis/AnalysisModuleTests.java
index efec81e803f1c..83cdab98a04f2 100644
--- a/server/src/test/java/org/opensearch/indices/analysis/AnalysisModuleTests.java
+++ b/server/src/test/java/org/opensearch/indices/analysis/AnalysisModuleTests.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.CharFilter;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
@@ -42,6 +41,7 @@
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.NIOFSDirectory;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -56,18 +56,18 @@
 import org.opensearch.index.analysis.CharFilterFactory;
 import org.opensearch.index.analysis.CustomAnalyzer;
 import org.opensearch.index.analysis.IndexAnalyzers;
+import org.opensearch.index.analysis.MyFilterTokenFilterFactory;
 import org.opensearch.index.analysis.PreConfiguredCharFilter;
 import org.opensearch.index.analysis.PreConfiguredTokenFilter;
 import org.opensearch.index.analysis.PreConfiguredTokenizer;
 import org.opensearch.index.analysis.StandardTokenizerFactory;
 import org.opensearch.index.analysis.StopTokenFilterFactory;
 import org.opensearch.index.analysis.TokenFilterFactory;
-import org.opensearch.index.analysis.MyFilterTokenFilterFactory;
 import org.opensearch.index.analysis.TokenizerFactory;
 import org.opensearch.indices.analysis.AnalysisModule.AnalysisProvider;
 import org.opensearch.plugins.AnalysisPlugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.hamcrest.MatcherAssert;
 
@@ -87,10 +87,10 @@
 
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
-import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 import static org.hamcrest.Matchers.either;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.apache.lucene.tests.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
 
 public class AnalysisModuleTests extends OpenSearchTestCase {
     private final Settings emptyNodeSettings = Settings.builder()
@@ -168,11 +168,12 @@ private void testSimpleConfiguration(Settings settings) throws IOException {
     }
 
     public void testWordListPath() throws Exception {
-        Settings settings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString()).build();
+        Path home = createTempDir();
+        Settings settings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), home.toString()).build();
         Environment env = TestEnvironment.newEnvironment(settings);
         String[] words = new String[] { "donau", "dampf", "schiff", "spargel", "creme", "suppe" };
 
-        Path wordListFile = generateWordList(words);
+        Path wordListFile = generateWordList(home, words);
         settings = Settings.builder()
             .loadFromSource("index: \n  word_list_path: " + wordListFile.toAbsolutePath(), XContentType.YAML)
             .build();
@@ -183,8 +184,10 @@ public void testWordListPath() throws Exception {
         Files.delete(wordListFile);
     }
 
-    private Path generateWordList(String[] words) throws Exception {
-        Path wordListFile = createTempDir().resolve("wordlist.txt");
+    private Path generateWordList(Path home, String[] words) throws Exception {
+        Path config = home.resolve("config");
+        Files.createDirectory(config);
+        Path wordListFile = config.resolve("wordlist.txt");
         try (BufferedWriter writer = Files.newBufferedWriter(wordListFile, StandardCharsets.UTF_8)) {
             for (String word : words) {
                 writer.write(word);
diff --git a/server/src/test/java/org/opensearch/indices/analyze/HunspellServiceTests.java b/server/src/test/java/org/opensearch/indices/analyze/HunspellServiceTests.java
index 28732b099ea30..f66045898f4a3 100644
--- a/server/src/test/java/org/opensearch/indices/analyze/HunspellServiceTests.java
+++ b/server/src/test/java/org/opensearch/indices/analyze/HunspellServiceTests.java
@@ -42,8 +42,6 @@
 import static java.util.Collections.emptyMap;
 import static org.opensearch.indices.analysis.HunspellService.HUNSPELL_IGNORE_CASE;
 import static org.opensearch.indices.analysis.HunspellService.HUNSPELL_LAZY_LOAD;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.hasToString;
 import static org.hamcrest.Matchers.notNullValue;
 
 public class HunspellServiceTests extends OpenSearchTestCase {
@@ -91,11 +89,11 @@ public void testDicWithNoAff() throws Exception {
             final Environment environment = new Environment(settings, getDataPath("/indices/analyze/no_aff_conf_dir"));
             new HunspellService(settings, environment, emptyMap()).getDictionary("en_US");
         });
-        assertEquals("failed to load hunspell dictionary for locale: en_US", e.getMessage());
-        assertThat(e.getCause(), hasToString(containsString("Missing affix file")));
+        assertEquals("Failed to load hunspell dictionary for locale: en_US", e.getMessage());
+        assertNull(e.getCause());
     }
 
-    public void testDicWithTwoAffs() throws Exception {
+    public void testDicWithTwoAffs() {
         Settings settings = Settings.builder()
             .put(HUNSPELL_LAZY_LOAD.getKey(), randomBoolean())
             .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
@@ -105,7 +103,7 @@ public void testDicWithTwoAffs() throws Exception {
             final Environment environment = new Environment(settings, getDataPath("/indices/analyze/two_aff_conf_dir"));
             new HunspellService(settings, environment, emptyMap()).getDictionary("en_US");
         });
-        assertEquals("failed to load hunspell dictionary for locale: en_US", e.getMessage());
-        assertThat(e.getCause(), hasToString(containsString("Too many affix files")));
+        assertEquals("Failed to load hunspell dictionary for locale: en_US", e.getMessage());
+        assertNull(e.getCause());
     }
 }
diff --git a/server/src/test/java/org/opensearch/indices/breaker/BreakerSettingsTests.java b/server/src/test/java/org/opensearch/indices/breaker/BreakerSettingsTests.java
index 93c3b0f48315d..c158d9add83f4 100644
--- a/server/src/test/java/org/opensearch/indices/breaker/BreakerSettingsTests.java
+++ b/server/src/test/java/org/opensearch/indices/breaker/BreakerSettingsTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.indices.breaker;
 
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerServiceTests.java b/server/src/test/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerServiceTests.java
index 7bdff59e7c334..591f8f15a1441 100644
--- a/server/src/test/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerServiceTests.java
+++ b/server/src/test/java/org/opensearch/indices/breaker/HierarchyCircuitBreakerServiceTests.java
@@ -33,26 +33,27 @@
 package org.opensearch.indices.breaker;
 
 import org.opensearch.common.breaker.ChildMemoryCircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.search.aggregations.MultiBucketConsumerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CyclicBarrier;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
diff --git a/server/src/test/java/org/opensearch/indices/cluster/AbstractIndicesClusterStateServiceTestCase.java b/server/src/test/java/org/opensearch/indices/cluster/AbstractIndicesClusterStateServiceTestCase.java
index 9d83071c177f5..c455101ff4549 100644
--- a/server/src/test/java/org/opensearch/indices/cluster/AbstractIndicesClusterStateServiceTestCase.java
+++ b/server/src/test/java/org/opensearch/indices/cluster/AbstractIndicesClusterStateServiceTestCase.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.indices.cluster;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -42,21 +41,25 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.PrimaryReplicaSyncer.ResyncTask;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndex;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices;
 import org.opensearch.indices.cluster.IndicesClusterStateService.Shard;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
+import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
@@ -252,14 +255,16 @@ public MockIndexService indexService(Index index) {
         @Override
         public MockIndexShard createShard(
             final ShardRouting shardRouting,
+            final SegmentReplicationCheckpointPublisher checkpointPublisher,
             final PeerRecoveryTargetService recoveryTargetService,
-            final PeerRecoveryTargetService.RecoveryListener recoveryListener,
+            final RecoveryListener recoveryListener,
             final RepositoriesService repositoriesService,
             final Consumer<IndexShard.ShardFailure> onShardFailure,
             final Consumer<ShardId> globalCheckpointSyncer,
             final RetentionLeaseSyncer retentionLeaseSyncer,
             final DiscoveryNode targetNode,
-            final DiscoveryNode sourceNode
+            final DiscoveryNode sourceNode,
+            final RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory
         ) throws IOException {
             failRandomly();
             RecoveryState recoveryState = new RecoveryState(shardRouting, targetNode, sourceNode);
diff --git a/server/src/test/java/org/opensearch/indices/cluster/ClusterStateChanges.java b/server/src/test/java/org/opensearch/indices/cluster/ClusterStateChanges.java
index 99ec043cc7801..82f34544f5fb5 100644
--- a/server/src/test/java/org/opensearch/indices/cluster/ClusterStateChanges.java
+++ b/server/src/test/java/org/opensearch/indices/cluster/ClusterStateChanges.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.admin.cluster.reroute.ClusterRerouteRequest;
 import org.opensearch.action.admin.cluster.reroute.TransportClusterRerouteAction;
 import org.opensearch.action.admin.indices.close.CloseIndexRequest;
@@ -55,9 +54,9 @@
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.DestructiveOperations;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
-import org.opensearch.action.support.master.TransportMasterNodeActionUtils;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
+import org.opensearch.action.support.clustermanager.TransportMasterNodeActionUtils;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskExecutor;
 import org.opensearch.cluster.ClusterStateTaskExecutor.ClusterTasksResult;
@@ -72,6 +71,7 @@
 import org.opensearch.cluster.metadata.AliasValidator;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataCreateIndexService;
 import org.opensearch.cluster.metadata.MetadataDeleteIndexService;
 import org.opensearch.cluster.metadata.MetadataIndexStateService;
@@ -81,6 +81,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.FailedShard;
 import org.opensearch.cluster.routing.allocation.RandomAllocationDeciderTests;
 import org.opensearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
@@ -88,24 +89,29 @@
 import org.opensearch.cluster.routing.allocation.decider.ReplicaAfterPrimaryActiveAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Priority;
 import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.Priority;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
 import org.opensearch.indices.SystemIndices;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
+import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.snapshots.EmptySnapshotsInfoService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.gateway.TestGatewayAllocator;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
@@ -121,10 +127,10 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.getRandom;
 import static java.util.Collections.emptyMap;
 import static org.opensearch.env.Environment.PATH_HOME_SETTING;
 import static org.hamcrest.Matchers.notNullValue;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.getRandom;
 import static org.junit.Assert.assertThat;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyString;
@@ -148,6 +154,8 @@ public class ClusterStateChanges {
     private final TransportUpdateSettingsAction transportUpdateSettingsAction;
     private final TransportClusterRerouteAction transportClusterRerouteAction;
     private final TransportCreateIndexAction transportCreateIndexAction;
+    private final RepositoriesService repositoriesService;
+    private final RemoteStoreNodeService remoteStoreNodeService;
 
     private final NodeRemovalClusterStateTaskExecutor nodeRemovalExecutor;
     private final JoinTaskExecutor joinTaskExecutor;
@@ -189,7 +197,13 @@ public ClusterStateChanges(NamedXContentRegistry xContentRegistry, ThreadPool th
 
         // mocks
         clusterService = mock(ClusterService.class);
+        Metadata metadata = Metadata.builder().build();
+        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .build();
+        when(clusterService.state()).thenReturn(clusterState);
         when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+        when(clusterService.getSettings()).thenReturn(SETTINGS);
         IndicesService indicesService = mock(IndicesService.class);
         // MetadataCreateIndexService uses withTempIndexService to check mappings -> fake it here
         try {
@@ -224,7 +238,8 @@ public ClusterStateChanges(NamedXContentRegistry xContentRegistry, ThreadPool th
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> DiscoveryNode.createLocal(SETTINGS, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
             clusterSettings,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         MetadataIndexUpgradeService metadataIndexUpgradeService = new MetadataIndexUpgradeService(
             SETTINGS,
@@ -259,7 +274,8 @@ public IndexMetadata upgradeIndexMetadata(IndexMetadata indexMetadata, Version m
             null,
             actionFilters
         );
-        ShardLimitValidator shardLimitValidator = new ShardLimitValidator(SETTINGS, clusterService);
+        final SystemIndices systemIndices = new SystemIndices(emptyMap());
+        ShardLimitValidator shardLimitValidator = new ShardLimitValidator(SETTINGS, clusterService, systemIndices);
         MetadataIndexStateService indexStateService = new MetadataIndexStateService(
             clusterService,
             allocationService,
@@ -271,13 +287,17 @@ public IndexMetadata upgradeIndexMetadata(IndexMetadata indexMetadata, Version m
             transportVerifyShardIndexBlockAction
         );
         MetadataDeleteIndexService deleteIndexService = new MetadataDeleteIndexService(SETTINGS, clusterService, allocationService);
+
+        final AwarenessReplicaBalance awarenessReplicaBalance = new AwarenessReplicaBalance(SETTINGS, clusterService.getClusterSettings());
+
         MetadataUpdateSettingsService metadataUpdateSettingsService = new MetadataUpdateSettingsService(
             clusterService,
             allocationService,
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             indicesService,
             shardLimitValidator,
-            threadPool
+            threadPool,
+            awarenessReplicaBalance
         );
         MetadataCreateIndexService createIndexService = new MetadataCreateIndexService(
             SETTINGS,
@@ -290,8 +310,9 @@ public IndexMetadata upgradeIndexMetadata(IndexMetadata indexMetadata, Version m
             IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
             threadPool,
             xContentRegistry,
-            new SystemIndices(emptyMap()),
-            true
+            systemIndices,
+            true,
+            awarenessReplicaBalance
         );
 
         transportCloseIndexAction = new TransportCloseIndexAction(
@@ -348,8 +369,26 @@ public IndexMetadata upgradeIndexMetadata(IndexMetadata indexMetadata, Version m
             indexNameExpressionResolver
         );
 
+        repositoriesService = new RepositoriesService(
+            Settings.EMPTY,
+            clusterService,
+            transportService,
+            Collections.emptyMap(),
+            Collections.emptyMap(),
+            threadPool
+        );
+
+        remoteStoreNodeService = new RemoteStoreNodeService(new SetOnce<>(repositoriesService)::get, threadPool);
+
         nodeRemovalExecutor = new NodeRemovalClusterStateTaskExecutor(allocationService, logger);
-        joinTaskExecutor = new JoinTaskExecutor(Settings.EMPTY, allocationService, logger, (s, p, r) -> {}, transportService);
+        joinTaskExecutor = new JoinTaskExecutor(
+            Settings.EMPTY,
+            allocationService,
+            logger,
+            (s, p, r) -> {},
+            transportService,
+            remoteStoreNodeService
+        );
     }
 
     public ClusterState createIndex(ClusterState state, CreateIndexRequest request) {
@@ -396,15 +435,21 @@ public ClusterState addNodes(ClusterState clusterState, List<DiscoveryNode> node
         );
     }
 
-    public ClusterState joinNodesAndBecomeMaster(ClusterState clusterState, List<DiscoveryNode> nodes) {
+    public ClusterState joinNodesAndBecomeClusterManager(ClusterState clusterState, List<DiscoveryNode> nodes) {
         List<JoinTaskExecutor.Task> joinNodes = new ArrayList<>();
-        joinNodes.add(JoinTaskExecutor.newBecomeMasterTask());
+        joinNodes.add(JoinTaskExecutor.newBecomeClusterManagerTask());
         joinNodes.add(JoinTaskExecutor.newFinishElectionTask());
         joinNodes.addAll(nodes.stream().map(node -> new JoinTaskExecutor.Task(node, "dummy reason")).collect(Collectors.toList()));
 
         return runTasks(joinTaskExecutor, clusterState, joinNodes);
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #joinNodesAndBecomeClusterManager(ClusterState, List)} */
+    @Deprecated
+    public ClusterState joinNodesAndBecomeMaster(ClusterState clusterState, List<DiscoveryNode> nodes) {
+        return joinNodesAndBecomeClusterManager(clusterState, nodes);
+    }
+
     public ClusterState removeNodes(ClusterState clusterState, List<DiscoveryNode> nodes) {
         return runTasks(
             nodeRemovalExecutor,
@@ -462,14 +507,19 @@ private <T> ClusterState runTasks(ClusterStateTaskExecutor<T> executor, ClusterS
         }
     }
 
-    private <Request extends MasterNodeRequest<Request>, Response extends ActionResponse> ClusterState execute(
-        TransportMasterNodeAction<Request, Response> masterNodeAction,
+    private <Request extends ClusterManagerNodeRequest<Request>, Response extends ActionResponse> ClusterState execute(
+        TransportClusterManagerNodeAction<Request, Response> masterNodeAction,
         Request request,
         ClusterState clusterState
     ) {
         return executeClusterStateUpdateTask(clusterState, () -> {
             try {
-                TransportMasterNodeActionUtils.runMasterOperation(masterNodeAction, request, clusterState, new PlainActionFuture<>());
+                TransportMasterNodeActionUtils.runClusterManagerOperation(
+                    masterNodeAction,
+                    request,
+                    clusterState,
+                    new PlainActionFuture<>()
+                );
             } catch (Exception e) {
                 throw new RuntimeException(e);
             }
diff --git a/server/src/test/java/org/opensearch/indices/cluster/IndicesClusterStateServiceRandomUpdatesTests.java b/server/src/test/java/org/opensearch/indices/cluster/IndicesClusterStateServiceRandomUpdatesTests.java
index 7789054cfdc16..6ba49e74196ee 100644
--- a/server/src/test/java/org/opensearch/indices/cluster/IndicesClusterStateServiceRandomUpdatesTests.java
+++ b/server/src/test/java/org/opensearch/indices/cluster/IndicesClusterStateServiceRandomUpdatesTests.java
@@ -47,7 +47,7 @@
 import org.opensearch.cluster.action.shard.ShardStateAction;
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.block.ClusterBlocks;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
@@ -61,12 +61,16 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
+import org.opensearch.indices.replication.SegmentReplicationSourceService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
@@ -133,7 +137,7 @@ public void testRandomClusterStateUpdates() {
                 }
             }
 
-            // apply cluster state to nodes (incl. master)
+            // apply cluster state to nodes (incl. cluster-manager)
             for (DiscoveryNode node : state.nodes()) {
                 IndicesClusterStateService indicesClusterStateService = clusterStateServiceMap.get(node);
                 ClusterState localState = adaptClusterStateToLocalNode(state, node);
@@ -327,7 +331,7 @@ public ClusterState randomInitialClusterState(
         Supplier<MockIndicesService> indicesServiceSupplier
     ) {
         List<DiscoveryNode> allNodes = new ArrayList<>();
-        DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the master
+        DiscoveryNode localNode = createNode(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE); // local node is the cluster-manager
         allNodes.add(localNode);
         // at least two nodes that have the data role so that we can allocate shards
         allNodes.add(createNode(DiscoveryNodeRole.DATA_ROLE));
@@ -367,21 +371,27 @@ public ClusterState randomlyUpdateClusterState(
         Map<DiscoveryNode, IndicesClusterStateService> clusterStateServiceMap,
         Supplier<MockIndicesService> indicesServiceSupplier
     ) {
-        // randomly remove no_master blocks
-        if (randomBoolean() && state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID)) {
+        // randomly remove no_cluster_manager blocks
+        if (randomBoolean() && state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID)) {
             state = ClusterState.builder(state)
-                .blocks(ClusterBlocks.builder().blocks(state.blocks()).removeGlobalBlock(NoMasterBlockService.NO_MASTER_BLOCK_ID))
+                .blocks(
+                    ClusterBlocks.builder()
+                        .blocks(state.blocks())
+                        .removeGlobalBlock(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID)
+                )
                 .build();
         }
 
-        // randomly add no_master blocks
-        if (rarely() && state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID) == false) {
-            ClusterBlock block = randomBoolean() ? NoMasterBlockService.NO_MASTER_BLOCK_ALL : NoMasterBlockService.NO_MASTER_BLOCK_WRITES;
+        // randomly add no_cluster_manager blocks
+        if (rarely() && state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID) == false) {
+            ClusterBlock block = randomBoolean()
+                ? NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ALL
+                : NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES;
             state = ClusterState.builder(state).blocks(ClusterBlocks.builder().blocks(state.blocks()).addGlobalBlock(block)).build();
         }
 
-        // if no_master block is in place, make no other cluster state changes
-        if (state.blocks().hasGlobalBlockWithId(NoMasterBlockService.NO_MASTER_BLOCK_ID)) {
+        // if no_cluster_manager block is in place, make no other cluster state changes
+        if (state.blocks().hasGlobalBlockWithId(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID)) {
             return state;
         }
 
@@ -407,7 +417,7 @@ public ClusterState randomlyUpdateClusterState(
         // randomly delete indices
         Set<String> indicesToDelete = new HashSet<>();
         int numberOfIndicesToDelete = randomInt(Math.min(2, state.metadata().indices().size()));
-        for (String index : randomSubsetOf(numberOfIndicesToDelete, state.metadata().indices().keys().toArray(String.class))) {
+        for (String index : randomSubsetOf(numberOfIndicesToDelete, state.metadata().indices().keySet().toArray(new String[0]))) {
             indicesToDelete.add(state.metadata().index(index).getIndex().getName());
         }
         if (indicesToDelete.isEmpty() == false) {
@@ -420,14 +430,14 @@ public ClusterState randomlyUpdateClusterState(
 
         // randomly close indices
         int numberOfIndicesToClose = randomInt(Math.min(1, state.metadata().indices().size()));
-        for (String index : randomSubsetOf(numberOfIndicesToClose, state.metadata().indices().keys().toArray(String.class))) {
+        for (String index : randomSubsetOf(numberOfIndicesToClose, state.metadata().indices().keySet().toArray(new String[0]))) {
             CloseIndexRequest closeIndexRequest = new CloseIndexRequest(state.metadata().index(index).getIndex().getName());
             state = cluster.closeIndices(state, closeIndexRequest);
         }
 
         // randomly open indices
         int numberOfIndicesToOpen = randomInt(Math.min(1, state.metadata().indices().size()));
-        for (String index : randomSubsetOf(numberOfIndicesToOpen, state.metadata().indices().keys().toArray(String.class))) {
+        for (String index : randomSubsetOf(numberOfIndicesToOpen, state.metadata().indices().keySet().toArray(new String[0]))) {
             OpenIndexRequest openIndexRequest = new OpenIndexRequest(state.metadata().index(index).getIndex().getName());
             state = cluster.openIndices(state, openIndexRequest);
         }
@@ -436,7 +446,7 @@ public ClusterState randomlyUpdateClusterState(
         Set<String> indicesToUpdate = new HashSet<>();
         boolean containsClosedIndex = false;
         int numberOfIndicesToUpdate = randomInt(Math.min(2, state.metadata().indices().size()));
-        for (String index : randomSubsetOf(numberOfIndicesToUpdate, state.metadata().indices().keys().toArray(String.class))) {
+        for (String index : randomSubsetOf(numberOfIndicesToUpdate, state.metadata().indices().keySet().toArray(new String[0]))) {
             indicesToUpdate.add(state.metadata().index(index).getIndex().getName());
             if (state.metadata().index(index).getState() == IndexMetadata.State.CLOSE) {
                 containsClosedIndex = true;
@@ -480,7 +490,7 @@ public ClusterState randomlyUpdateClusterState(
         state = cluster.applyFailedShards(state, failedShards);
         state = cluster.applyStartedShards(state, startedShards);
 
-        // randomly add and remove nodes (except current master)
+        // randomly add and remove nodes (except current cluster-manager)
         if (rarely()) {
             if (randomBoolean()) {
                 // add node
@@ -491,8 +501,8 @@ public ClusterState randomlyUpdateClusterState(
             } else {
                 // remove node
                 if (state.nodes().getDataNodes().size() > 3) {
-                    DiscoveryNode discoveryNode = randomFrom(state.nodes().getNodes().values().toArray(DiscoveryNode.class));
-                    if (discoveryNode.equals(state.nodes().getMasterNode()) == false) {
+                    DiscoveryNode discoveryNode = randomFrom(state.nodes().getNodes().values().toArray(new DiscoveryNode[0]));
+                    if (discoveryNode.equals(state.nodes().getClusterManagerNode()) == false) {
                         state = cluster.removeNodes(state, Collections.singletonList(discoveryNode));
                         updateNodes(state, clusterStateServiceMap, indicesServiceSupplier);
                     }
@@ -505,7 +515,7 @@ public ClusterState randomlyUpdateClusterState(
             }
         }
 
-        // TODO: go masterless?
+        // TODO: go cluster-managerless?
 
         return state;
     }
@@ -538,7 +548,8 @@ private IndicesClusterStateService createIndicesClusterStateService(
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> DiscoveryNode.createLocal(settings, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         final ClusterService clusterService = mock(ClusterService.class);
         final RepositoriesService repositoriesService = new RepositoriesService(
@@ -562,6 +573,9 @@ private IndicesClusterStateService createIndicesClusterStateService(
             indicesService,
             clusterService,
             threadPool,
+            SegmentReplicationCheckpointPublisher.EMPTY,
+            mock(SegmentReplicationTargetService.class),
+            mock(SegmentReplicationSourceService.class),
             recoveryTargetService,
             shardStateAction,
             null,
@@ -571,7 +585,8 @@ private IndicesClusterStateService createIndicesClusterStateService(
             null,
             primaryReplicaSyncer,
             s -> {},
-            RetentionLeaseSyncer.EMPTY
+            RetentionLeaseSyncer.EMPTY,
+            null
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/indices/memory/breaker/CircuitBreakerUnitTests.java b/server/src/test/java/org/opensearch/indices/memory/breaker/CircuitBreakerUnitTests.java
index a2705a0730aaf..aeadcf91e3e21 100644
--- a/server/src/test/java/org/opensearch/indices/memory/breaker/CircuitBreakerUnitTests.java
+++ b/server/src/test/java/org/opensearch/indices/memory/breaker/CircuitBreakerUnitTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.indices.memory.breaker;
 
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
 import org.opensearch.indices.breaker.BreakerSettings;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java b/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java
new file mode 100644
index 0000000000000..4685a7196b85a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java
@@ -0,0 +1,1220 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.store.BaseDirectoryWrapper;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.Version;
+import org.opensearch.action.LatchedActionListener;
+import org.opensearch.action.StepListener;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.Numbers;
+import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.lucene.store.IndexOutputOutputStream;
+import org.opensearch.common.lucene.uid.Versions;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.util.FileSystemUtils;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.RecoveryEngineException;
+import org.opensearch.index.engine.SegmentsStats;
+import org.opensearch.index.mapper.IdFieldMapper;
+import org.opensearch.index.mapper.ParseContext;
+import org.opensearch.index.mapper.ParsedDocument;
+import org.opensearch.index.mapper.SeqNoFieldMapper;
+import org.opensearch.index.mapper.Uid;
+import org.opensearch.index.seqno.ReplicationTracker;
+import org.opensearch.index.seqno.RetentionLease;
+import org.opensearch.index.seqno.RetentionLeases;
+import org.opensearch.index.seqno.SeqNoStats;
+import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardRelocatedException;
+import org.opensearch.index.shard.IndexShardState;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.RunUnderPrimaryPermit;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.test.CorruptionUtils;
+import org.opensearch.test.DummyShardLock;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.VersionUtils;
+import org.opensearch.threadpool.FixedExecutorBuilder;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.IntSupplier;
+import java.util.stream.Collectors;
+import java.util.zip.CRC32;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyBoolean;
+import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * This covers test cases for {@link RecoverySourceHandler} and {@link LocalStorePeerRecoverySourceHandler}.
+ */
+public class LocalStorePeerRecoverySourceHandlerTests extends OpenSearchTestCase {
+    private static final IndexSettings INDEX_SETTINGS = IndexSettingsModule.newIndexSettings(
+        "index",
+        Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT).build()
+    );
+    private final ShardId shardId = new ShardId(INDEX_SETTINGS.getIndex(), 1);
+    private final ClusterSettings service = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+
+    private ThreadPool threadPool;
+    private Executor recoveryExecutor;
+
+    @Before
+    public void setUpThreadPool() {
+        if (randomBoolean()) {
+            threadPool = new TestThreadPool(getTestName());
+            recoveryExecutor = threadPool.generic();
+        } else {
+            // verify that both sending and receiving files can be completed with a single thread
+            threadPool = new TestThreadPool(
+                getTestName(),
+                new FixedExecutorBuilder(Settings.EMPTY, "recovery_executor", between(1, 16), between(16, 128), "recovery_executor")
+            );
+            recoveryExecutor = threadPool.executor("recovery_executor");
+        }
+    }
+
+    @After
+    public void tearDownThreadPool() {
+        terminate(threadPool);
+    }
+
+    public void testSendFiles() throws Throwable {
+        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        Store store = newStore(createTempDir());
+        Directory dir = store.directory();
+        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
+        int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            Document document = new Document();
+            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
+            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
+            writer.addDocument(document);
+        }
+        writer.commit();
+        writer.close();
+
+        Store.MetadataSnapshot metadata = store.getMetadata();
+        ReplicationLuceneIndex luceneIndex = new ReplicationLuceneIndex();
+        List<StoreFileMetadata> metas = new ArrayList<>();
+        for (StoreFileMetadata md : metadata) {
+            metas.add(md);
+            luceneIndex.addFileDetail(md.name(), md.length(), false);
+        }
+        Store targetStore = newStore(createTempDir());
+        MultiFileWriter multiFileWriter = new MultiFileWriter(targetStore, luceneIndex, "", logger, () -> {});
+        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                ActionListener.completeWith(listener, () -> {
+                    multiFileWriter.writeFileChunk(md, position, content, lastChunk);
+                    return null;
+                });
+            }
+        };
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            null,
+            new AsyncRecoveryTarget(target, recoveryExecutor),
+            threadPool,
+            request,
+            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+            between(1, 5),
+            between(1, 5)
+        );
+        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
+        handler.sendFiles(store, metas.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
+        sendFilesFuture.actionGet();
+        Store.MetadataSnapshot targetStoreMetadata = targetStore.getMetadata();
+        Store.RecoveryDiff recoveryDiff = targetStoreMetadata.recoveryDiff(metadata);
+        assertEquals(metas.size(), recoveryDiff.identical.size());
+        assertEquals(0, recoveryDiff.different.size());
+        assertEquals(0, recoveryDiff.missing.size());
+        IndexReader reader = DirectoryReader.open(targetStore.directory());
+        assertEquals(numDocs, reader.maxDoc());
+        IOUtils.close(reader, store, multiFileWriter, targetStore);
+    }
+
+    public StartRecoveryRequest getStartRecoveryRequest() throws IOException {
+        Store.MetadataSnapshot metadataSnapshot = randomBoolean()
+            ? Store.MetadataSnapshot.EMPTY
+            : new Store.MetadataSnapshot(
+                Collections.emptyMap(),
+                Collections.singletonMap(Engine.HISTORY_UUID_KEY, UUIDs.randomBase64UUID()),
+                randomIntBetween(0, 100)
+            );
+        return new StartRecoveryRequest(
+            shardId,
+            null,
+            new DiscoveryNode("b", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT),
+            new DiscoveryNode("b", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT),
+            metadataSnapshot,
+            randomBoolean(),
+            randomNonNegativeLong(),
+            randomBoolean() || metadataSnapshot.getHistoryUUID() == null ? SequenceNumbers.UNASSIGNED_SEQ_NO : randomNonNegativeLong()
+        );
+    }
+
+    public void testSendSnapshotSendsOps() throws IOException {
+        final int fileChunkSizeInBytes = between(1, 4096);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        final IndexShard shard = mock(IndexShard.class);
+        when(shard.state()).thenReturn(IndexShardState.STARTED);
+        final List<Translog.Operation> operations = new ArrayList<>();
+        final int initialNumberOfDocs = randomIntBetween(10, 1000);
+        for (int i = 0; i < initialNumberOfDocs; i++) {
+            final Engine.Index index = getIndex(Integer.toString(i));
+            operations.add(new Translog.Index(index, new Engine.IndexResult(1, 1, SequenceNumbers.UNASSIGNED_SEQ_NO, true)));
+        }
+        final int numberOfDocsWithValidSequenceNumbers = randomIntBetween(10, 1000);
+        for (int i = initialNumberOfDocs; i < initialNumberOfDocs + numberOfDocsWithValidSequenceNumbers; i++) {
+            final Engine.Index index = getIndex(Integer.toString(i));
+            operations.add(new Translog.Index(index, new Engine.IndexResult(1, 1, i - initialNumberOfDocs, true)));
+        }
+        final long startingSeqNo = randomIntBetween(0, numberOfDocsWithValidSequenceNumbers - 1);
+        final long endingSeqNo = randomLongBetween(startingSeqNo, numberOfDocsWithValidSequenceNumbers - 1);
+
+        final Queue<Translog.Operation> shippedOps = ConcurrentCollections.newQueue();
+        final AtomicLong checkpointOnTarget = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        RecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
+            @Override
+            public void indexTranslogOperations(
+                List<Translog.Operation> operations,
+                int totalTranslogOps,
+                long timestamp,
+                long msu,
+                RetentionLeases retentionLeases,
+                long mappingVersion,
+                ActionListener<Long> listener
+            ) {
+                shippedOps.addAll(operations);
+                if (randomBoolean()) {
+                    checkpointOnTarget.addAndGet(between(1, 20));
+                }
+                listener.onResponse(checkpointOnTarget.get());
+            }
+        };
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic()),
+            threadPool,
+            request,
+            fileChunkSizeInBytes,
+            between(1, 10),
+            between(1, 10)
+        );
+        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> future = new PlainActionFuture<>();
+        handler.phase2(
+            startingSeqNo,
+            endingSeqNo,
+            newTranslogSnapshot(operations, Collections.emptyList()),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            RetentionLeases.EMPTY,
+            randomNonNegativeLong(),
+            future
+        );
+        final int expectedOps = (int) (endingSeqNo - startingSeqNo + 1);
+        RecoverySourceHandler.SendSnapshotResult result = future.actionGet();
+        assertThat(result.sentOperations, equalTo(expectedOps));
+        List<Translog.Operation> sortedShippedOps = shippedOps.stream()
+            .sorted(Comparator.comparing(Translog.Operation::seqNo))
+            .collect(Collectors.toList());
+        assertThat(shippedOps.size(), equalTo(expectedOps));
+        for (int i = 0; i < shippedOps.size(); i++) {
+            assertThat(sortedShippedOps.get(i), equalTo(operations.get(i + (int) startingSeqNo + initialNumberOfDocs)));
+        }
+        assertThat(result.targetLocalCheckpoint, equalTo(checkpointOnTarget.get()));
+    }
+
+    public void testSendSnapshotStopOnError() throws Exception {
+        final int fileChunkSizeInBytes = between(1, 10 * 1024);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        final IndexShard shard = mock(IndexShard.class);
+        when(shard.state()).thenReturn(IndexShardState.STARTED);
+        final List<Translog.Operation> ops = new ArrayList<>();
+        for (int numOps = between(1, 256), i = 0; i < numOps; i++) {
+            final Engine.Index index = getIndex(Integer.toString(i));
+            ops.add(new Translog.Index(index, new Engine.IndexResult(1, 1, i, true)));
+        }
+        final AtomicBoolean wasFailed = new AtomicBoolean();
+        RecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
+            @Override
+            public void indexTranslogOperations(
+                List<Translog.Operation> operations,
+                int totalTranslogOps,
+                long timestamp,
+                long msu,
+                RetentionLeases retentionLeases,
+                long mappingVersion,
+                ActionListener<Long> listener
+            ) {
+                if (randomBoolean()) {
+                    listener.onResponse(SequenceNumbers.NO_OPS_PERFORMED);
+                } else {
+                    listener.onFailure(new RuntimeException("test - failed to index"));
+                    wasFailed.set(true);
+                }
+            }
+        };
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic()),
+            threadPool,
+            request,
+            fileChunkSizeInBytes,
+            between(1, 10),
+            between(1, 10)
+        );
+        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> future = new PlainActionFuture<>();
+        final long startingSeqNo = randomLongBetween(0, ops.size() - 1L);
+        final long endingSeqNo = randomLongBetween(startingSeqNo, ops.size() - 1L);
+        handler.phase2(
+            startingSeqNo,
+            endingSeqNo,
+            newTranslogSnapshot(ops, Collections.emptyList()),
+            randomNonNegativeLong(),
+            randomNonNegativeLong(),
+            RetentionLeases.EMPTY,
+            randomNonNegativeLong(),
+            future
+        );
+        if (wasFailed.get()) {
+            final RecoveryEngineException error = expectThrows(RecoveryEngineException.class, future::actionGet);
+            assertThat(error.getMessage(), equalTo("Phase[2] failed to send/replay operations"));
+            assertThat(error.getCause().getMessage(), equalTo("test - failed to index"));
+        }
+    }
+
+    public void testSendOperationsConcurrently() throws Throwable {
+        final IndexShard shard = mock(IndexShard.class);
+        when(shard.state()).thenReturn(IndexShardState.STARTED);
+        Set<Long> receivedSeqNos = ConcurrentCollections.newConcurrentSet();
+        long maxSeenAutoIdTimestamp = randomBoolean() ? -1 : randomNonNegativeLong();
+        long maxSeqNoOfUpdatesOrDeletes = randomBoolean() ? -1 : randomNonNegativeLong();
+        RetentionLeases retentionLeases = new RetentionLeases(randomNonNegativeLong(), randomNonNegativeLong(), Collections.emptySet());
+        long mappingVersion = randomNonNegativeLong();
+        AtomicLong localCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
+        int numOps = randomIntBetween(0, 1000);
+        AtomicBoolean received = new AtomicBoolean();
+        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
+            @Override
+            public void indexTranslogOperations(
+                List<Translog.Operation> operations,
+                int receivedTotalOps,
+                long receivedMaxSeenAutoIdTimestamp,
+                long receivedMaxSeqNoOfUpdatesOrDeletes,
+                RetentionLeases receivedRetentionLease,
+                long receivedMappingVersion,
+                ActionListener<Long> listener
+            ) {
+                received.set(true);
+                assertThat(receivedMaxSeenAutoIdTimestamp, equalTo(maxSeenAutoIdTimestamp));
+                assertThat(receivedMaxSeqNoOfUpdatesOrDeletes, equalTo(maxSeqNoOfUpdatesOrDeletes));
+                assertThat(receivedRetentionLease, equalTo(retentionLeases));
+                assertThat(receivedMappingVersion, equalTo(mappingVersion));
+                assertThat(receivedTotalOps, equalTo(numOps));
+                for (Translog.Operation operation : operations) {
+                    receivedSeqNos.add(operation.seqNo());
+                }
+                if (randomBoolean()) {
+                    localCheckpoint.addAndGet(randomIntBetween(1, 100));
+                }
+                listener.onResponse(localCheckpoint.get());
+            }
+        };
+
+        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> sendFuture = new PlainActionFuture<>();
+        long startingSeqNo = randomIntBetween(0, 1000);
+        long endingSeqNo = startingSeqNo + randomIntBetween(0, 10000);
+        List<Translog.Operation> operations = generateOperations(numOps);
+        Randomness.shuffle(operations);
+        List<Translog.Operation> skipOperations = randomSubsetOf(operations);
+        Translog.Snapshot snapshot = newTranslogSnapshot(operations, skipOperations);
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            new AsyncRecoveryTarget(target, recoveryExecutor),
+            threadPool,
+            getStartRecoveryRequest(),
+            between(1, 10 * 1024),
+            between(1, 5),
+            between(1, 5)
+        );
+        handler.phase2(
+            startingSeqNo,
+            endingSeqNo,
+            snapshot,
+            maxSeenAutoIdTimestamp,
+            maxSeqNoOfUpdatesOrDeletes,
+            retentionLeases,
+            mappingVersion,
+            sendFuture
+        );
+        RecoverySourceHandler.SendSnapshotResult sendSnapshotResult = sendFuture.actionGet();
+        assertTrue(received.get());
+        assertThat(sendSnapshotResult.targetLocalCheckpoint, equalTo(localCheckpoint.get()));
+        assertThat(sendSnapshotResult.sentOperations, equalTo(receivedSeqNos.size()));
+        Set<Long> sentSeqNos = new HashSet<>();
+        for (Translog.Operation op : operations) {
+            if (startingSeqNo <= op.seqNo() && op.seqNo() <= endingSeqNo && skipOperations.contains(op) == false) {
+                sentSeqNos.add(op.seqNo());
+            }
+        }
+        assertThat(receivedSeqNos, equalTo(sentSeqNos));
+    }
+
+    private Engine.Index getIndex(final String id) {
+        final ParseContext.Document document = new ParseContext.Document();
+        document.add(new TextField("test", "test", Field.Store.YES));
+        final Field idField = new Field("_id", Uid.encodeId(id), IdFieldMapper.Defaults.FIELD_TYPE);
+        final Field versionField = new NumericDocValuesField("_version", Versions.MATCH_ANY);
+        final SeqNoFieldMapper.SequenceIDFields seqID = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
+        document.add(idField);
+        document.add(versionField);
+        document.add(seqID.seqNo);
+        document.add(seqID.seqNoDocValue);
+        document.add(seqID.primaryTerm);
+        final BytesReference source = new BytesArray(new byte[] { 1 });
+        final ParsedDocument doc = new ParsedDocument(
+            versionField,
+            seqID,
+            id,
+            null,
+            Arrays.asList(document),
+            source,
+            MediaTypeRegistry.JSON,
+            null
+        );
+        return new Engine.Index(new Term("_id", Uid.encodeId(doc.id())), randomNonNegativeLong(), doc);
+    }
+
+    public void testHandleCorruptedIndexOnSendSendFiles() throws Throwable {
+        Settings settings = Settings.builder()
+            .put("indices.recovery.concurrent_streams", 1)
+            .put("indices.recovery.concurrent_small_file_streams", 1)
+            .build();
+        final RecoverySettings recoverySettings = new RecoverySettings(settings, service);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        Path tempDir = createTempDir();
+        Store store = newStore(tempDir, false);
+        AtomicBoolean failedEngine = new AtomicBoolean(false);
+        Directory dir = store.directory();
+        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
+        int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            Document document = new Document();
+            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
+            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
+            writer.addDocument(document);
+        }
+        writer.commit();
+        writer.close();
+
+        ReplicationLuceneIndex luceneIndex = new ReplicationLuceneIndex();
+        Store.MetadataSnapshot metadata = store.getMetadata();
+        List<StoreFileMetadata> metas = new ArrayList<>();
+        for (StoreFileMetadata md : metadata) {
+            metas.add(md);
+            luceneIndex.addFileDetail(md.name(), md.length(), false);
+        }
+
+        CorruptionUtils.corruptFile(
+            random(),
+            FileSystemUtils.files(
+                tempDir,
+                (p) -> (p.getFileName().toString().equals("write.lock") || p.getFileName().toString().startsWith("extra")) == false
+            )
+        );
+        Store targetStore = newStore(createTempDir(), false);
+        MultiFileWriter multiFileWriter = new MultiFileWriter(targetStore, luceneIndex, "", logger, () -> {});
+        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                ActionListener.completeWith(listener, () -> {
+                    multiFileWriter.writeFileChunk(md, position, content, lastChunk);
+                    return null;
+                });
+            }
+        };
+        IndexShard mockShard = mock(IndexShard.class);
+        when(mockShard.shardId()).thenReturn(new ShardId("testIndex", "testUUID", 0));
+        doAnswer(invocation -> {
+            assertFalse(failedEngine.get());
+            failedEngine.set(true);
+            return null;
+        }).when(mockShard).failShard(any(), any());
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            mockShard,
+            new AsyncRecoveryTarget(target, recoveryExecutor),
+            threadPool,
+            request,
+            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+            between(1, 8),
+            between(1, 8)
+        );
+        SetOnce<Exception> sendFilesError = new SetOnce<>();
+        CountDownLatch latch = new CountDownLatch(1);
+        handler.sendFiles(
+            store,
+            metas.toArray(new StoreFileMetadata[0]),
+            () -> 0,
+            new LatchedActionListener<>(ActionListener.wrap(r -> sendFilesError.set(null), e -> sendFilesError.set(e)), latch)
+        );
+        latch.await();
+        assertThat(sendFilesError.get(), instanceOf(IOException.class));
+        assertNotNull(ExceptionsHelper.unwrapCorruption(sendFilesError.get()));
+        failedEngine.get();
+        assertTrue(failedEngine.get());
+        // ensure all chunk requests have been completed; otherwise some files on the target are left open.
+        IOUtils.close(() -> terminate(threadPool), () -> threadPool = null);
+        IOUtils.close(store, multiFileWriter, targetStore);
+    }
+
+    public void testHandleExceptionOnSendFiles() throws Throwable {
+        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        Path tempDir = createTempDir();
+        Store store = newStore(tempDir, false);
+        AtomicBoolean failedEngine = new AtomicBoolean(false);
+        Directory dir = store.directory();
+        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
+        int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            Document document = new Document();
+            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
+            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
+            writer.addDocument(document);
+        }
+        writer.commit();
+        writer.close();
+
+        Store.MetadataSnapshot metadata = store.getMetadata();
+        List<StoreFileMetadata> metas = new ArrayList<>();
+        for (StoreFileMetadata md : metadata) {
+            metas.add(md);
+        }
+        final boolean throwCorruptedIndexException = randomBoolean();
+        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                if (throwCorruptedIndexException) {
+                    listener.onFailure(new RuntimeException(new CorruptIndexException("foo", "bar")));
+                } else {
+                    listener.onFailure(new RuntimeException("boom"));
+                }
+            }
+        };
+        IndexShard mockShard = mock(IndexShard.class);
+        when(mockShard.shardId()).thenReturn(new ShardId("testIndex", "testUUID", 0));
+        doAnswer(invocation -> {
+            assertFalse(failedEngine.get());
+            failedEngine.set(true);
+            return null;
+        }).when(mockShard).failShard(any(), any());
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            mockShard,
+            new AsyncRecoveryTarget(target, recoveryExecutor),
+            threadPool,
+            request,
+            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+            between(1, 10),
+            between(1, 4)
+        );
+        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
+        handler.sendFiles(store, metas.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
+        Exception ex = expectThrows(Exception.class, sendFilesFuture::actionGet);
+        final IOException unwrappedCorruption = ExceptionsHelper.unwrapCorruption(ex);
+        if (throwCorruptedIndexException) {
+            assertNotNull(unwrappedCorruption);
+            assertEquals(ex.getMessage(), "[File corruption occurred on recovery but checksums are ok]");
+        } else {
+            assertNull(unwrappedCorruption);
+            assertEquals(ex.getMessage(), "boom");
+        }
+        assertFalse(failedEngine.get());
+        IOUtils.close(store);
+    }
+
+    public void testThrowExceptionOnPrimaryRelocatedBeforePhase1Started() throws IOException {
+        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
+        final StartRecoveryRequest request = getStartRecoveryRequest();
+        final IndexShard shard = mock(IndexShard.class);
+        when(shard.seqNoStats()).thenReturn(mock(SeqNoStats.class));
+        when(shard.segmentStats(anyBoolean(), anyBoolean())).thenReturn(mock(SegmentsStats.class));
+        when(shard.isRelocatedPrimary()).thenReturn(true);
+        when(shard.acquireSafeIndexCommit()).thenReturn(mock(GatedCloseable.class));
+        doAnswer(invocation -> {
+            ((ActionListener<Releasable>) invocation.getArguments()[0]).onResponse(() -> {});
+            return null;
+        }).when(shard).acquirePrimaryOperationPermit(any(), anyString(), any());
+
+        final IndexMetadata.Builder indexMetadata = IndexMetadata.builder("test")
+            .settings(
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, between(0, 5))
+                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, between(1, 5))
+                    .put(IndexMetadata.SETTING_VERSION_CREATED, VersionUtils.randomVersion(random()))
+                    .put(IndexMetadata.SETTING_INDEX_UUID, UUIDs.randomBase64UUID(random()))
+            );
+        if (randomBoolean()) {
+            indexMetadata.state(IndexMetadata.State.CLOSE);
+        }
+        when(shard.indexSettings()).thenReturn(new IndexSettings(indexMetadata.build(), Settings.EMPTY));
+
+        final AtomicBoolean phase1Called = new AtomicBoolean();
+        final AtomicBoolean prepareTargetForTranslogCalled = new AtomicBoolean();
+        final AtomicBoolean phase2Called = new AtomicBoolean();
+        final RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            mock(RecoveryTargetHandler.class),
+            threadPool,
+            request,
+            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
+            between(1, 8),
+            between(1, 8)
+        ) {
+
+            @Override
+            void phase1(
+                IndexCommit snapshot,
+                long startingSeqNo,
+                IntSupplier translogOps,
+                ActionListener<SendFileResult> listener,
+                boolean skipCreateRetentionLeaseStep
+            ) {
+                phase1Called.set(true);
+                super.phase1(snapshot, startingSeqNo, translogOps, listener, skipCreateRetentionLeaseStep);
+            }
+
+            @Override
+            void prepareTargetForTranslog(int totalTranslogOps, ActionListener<TimeValue> listener) {
+                prepareTargetForTranslogCalled.set(true);
+                super.prepareTargetForTranslog(totalTranslogOps, listener);
+            }
+
+            @Override
+            void phase2(
+                long startingSeqNo,
+                long endingSeqNo,
+                Translog.Snapshot snapshot,
+                long maxSeenAutoIdTimestamp,
+                long maxSeqNoOfUpdatesOrDeletes,
+                RetentionLeases retentionLeases,
+                long mappingVersion,
+                ActionListener<SendSnapshotResult> listener
+            ) throws IOException {
+                phase2Called.set(true);
+                super.phase2(
+                    startingSeqNo,
+                    endingSeqNo,
+                    snapshot,
+                    maxSeenAutoIdTimestamp,
+                    maxSeqNoOfUpdatesOrDeletes,
+                    retentionLeases,
+                    mappingVersion,
+                    listener
+                );
+            }
+
+        };
+        PlainActionFuture<RecoveryResponse> future = new PlainActionFuture<>();
+        expectThrows(IndexShardRelocatedException.class, () -> {
+            handler.recoverToTarget(future);
+            future.actionGet();
+        });
+        assertFalse(phase1Called.get());
+        assertFalse(prepareTargetForTranslogCalled.get());
+        assertFalse(phase2Called.get());
+    }
+
+    public void testCancellationsDoesNotLeakPrimaryPermits() throws Exception {
+        final CancellableThreads cancellableThreads = new CancellableThreads();
+        final IndexShard shard = mock(IndexShard.class);
+        final AtomicBoolean freed = new AtomicBoolean(true);
+        when(shard.isRelocatedPrimary()).thenReturn(false);
+        doAnswer(invocation -> {
+            freed.set(false);
+            ((ActionListener<Releasable>) invocation.getArguments()[0]).onResponse(() -> freed.set(true));
+            return null;
+        }).when(shard).acquirePrimaryOperationPermit(any(), anyString(), any());
+
+        Thread cancelingThread = new Thread(() -> cancellableThreads.cancel("test"));
+        cancelingThread.start();
+        try {
+            RunUnderPrimaryPermit.run(() -> {}, "test", shard, cancellableThreads, logger);
+        } catch (CancellableThreads.ExecutionCancelledException e) {
+            // expected.
+        }
+        cancelingThread.join();
+        // we have to use assert busy as we may be interrupted while acquiring the permit, if so we want to check
+        // that the permit is released.
+        assertBusy(() -> assertTrue(freed.get()));
+    }
+
+    public void testSendFileChunksConcurrently() throws Exception {
+        final IndexShard shard = mock(IndexShard.class);
+        when(shard.state()).thenReturn(IndexShardState.STARTED);
+        final List<FileChunkResponse> unrepliedChunks = new CopyOnWriteArrayList<>();
+        final AtomicInteger sentChunks = new AtomicInteger();
+        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
+            final AtomicLong chunkNumberGenerator = new AtomicLong();
+
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                final long chunkNumber = chunkNumberGenerator.getAndIncrement();
+                logger.info("--> write chunk name={} seq={}, position={}", md.name(), chunkNumber, position);
+                unrepliedChunks.add(new FileChunkResponse(chunkNumber, listener));
+                sentChunks.incrementAndGet();
+            }
+        };
+        final int maxConcurrentChunks = between(1, 8);
+        final int chunkSize = between(1, 32);
+        final RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            recoveryTarget,
+            threadPool,
+            getStartRecoveryRequest(),
+            chunkSize,
+            maxConcurrentChunks,
+            between(1, 10)
+        );
+        Store store = newStore(createTempDir(), false);
+        List<StoreFileMetadata> files = generateFiles(store, between(1, 10), () -> between(1, chunkSize * 20));
+        int totalChunks = files.stream().mapToInt(md -> ((int) md.length() + chunkSize - 1) / chunkSize).sum();
+        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
+        handler.sendFiles(store, files.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
+        assertBusy(() -> {
+            assertThat(sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks)));
+            assertThat(unrepliedChunks, hasSize(sentChunks.get()));
+        });
+
+        List<FileChunkResponse> ackedChunks = new ArrayList<>();
+        while (sentChunks.get() < totalChunks || unrepliedChunks.isEmpty() == false) {
+            List<FileChunkResponse> chunksToAck = randomSubsetOf(between(1, unrepliedChunks.size()), unrepliedChunks);
+            unrepliedChunks.removeAll(chunksToAck);
+            ackedChunks.addAll(chunksToAck);
+            ackedChunks.sort(Comparator.comparing(c -> c.chunkNumber));
+            int checkpoint = -1;
+            for (int i = 0; i < ackedChunks.size(); i++) {
+                if (i != ackedChunks.get(i).chunkNumber) {
+                    break;
+                } else {
+                    checkpoint = i;
+                }
+            }
+            int chunksToSend = Math.min(
+                totalChunks - sentChunks.get(),                             // limited by the remaining chunks
+                maxConcurrentChunks - (sentChunks.get() - 1 - checkpoint)
+            ); // limited by the buffering chunks
+
+            int expectedSentChunks = sentChunks.get() + chunksToSend;
+            int expectedUnrepliedChunks = unrepliedChunks.size() + chunksToSend;
+            chunksToAck.forEach(c -> c.listener.onResponse(null));
+            assertBusy(() -> {
+                assertThat(sentChunks.get(), equalTo(expectedSentChunks));
+                assertThat(unrepliedChunks, hasSize(expectedUnrepliedChunks));
+            });
+        }
+        sendFilesFuture.actionGet();
+        store.close();
+    }
+
+    public void testSendFileChunksStopOnError() throws Exception {
+        final List<FileChunkResponse> unrepliedChunks = new CopyOnWriteArrayList<>();
+        final AtomicInteger sentChunks = new AtomicInteger();
+        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
+            final AtomicLong chunkNumberGenerator = new AtomicLong();
+
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                final long chunkNumber = chunkNumberGenerator.getAndIncrement();
+                logger.info("--> write chunk name={} seq={}, position={}", md.name(), chunkNumber, position);
+                unrepliedChunks.add(new FileChunkResponse(chunkNumber, listener));
+                sentChunks.incrementAndGet();
+            }
+        };
+        final int maxConcurrentChunks = between(1, 4);
+        final int chunkSize = between(1, 16);
+        final RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            null,
+            new AsyncRecoveryTarget(recoveryTarget, recoveryExecutor),
+            threadPool,
+            getStartRecoveryRequest(),
+            chunkSize,
+            maxConcurrentChunks,
+            between(1, 5)
+        );
+        Store store = newStore(createTempDir(), false);
+        List<StoreFileMetadata> files = generateFiles(store, between(1, 10), () -> between(1, chunkSize * 20));
+        int totalChunks = files.stream().mapToInt(md -> ((int) md.length() + chunkSize - 1) / chunkSize).sum();
+        SetOnce<Exception> sendFilesError = new SetOnce<>();
+        CountDownLatch sendFilesLatch = new CountDownLatch(1);
+        handler.sendFiles(
+            store,
+            files.toArray(new StoreFileMetadata[0]),
+            () -> 0,
+            new LatchedActionListener<>(ActionListener.wrap(r -> sendFilesError.set(null), e -> sendFilesError.set(e)), sendFilesLatch)
+        );
+        assertBusy(() -> assertThat(sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks))));
+        List<FileChunkResponse> failedChunks = randomSubsetOf(between(1, unrepliedChunks.size()), unrepliedChunks);
+        CountDownLatch replyLatch = new CountDownLatch(failedChunks.size());
+        failedChunks.forEach(c -> {
+            c.listener.onFailure(new IllegalStateException("test chunk exception"));
+            replyLatch.countDown();
+        });
+        replyLatch.await();
+        unrepliedChunks.removeAll(failedChunks);
+        unrepliedChunks.forEach(c -> {
+            if (randomBoolean()) {
+                c.listener.onFailure(new RuntimeException("test"));
+            } else {
+                c.listener.onResponse(null);
+            }
+        });
+        sendFilesLatch.await();
+        assertThat(sendFilesError.get(), instanceOf(IllegalStateException.class));
+        assertThat(sendFilesError.get().getMessage(), containsString("test chunk exception"));
+        assertThat("no more chunks should be sent", sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks)));
+        store.close();
+    }
+
+    public void testCancelRecoveryDuringPhase1() throws Exception {
+        Store store = newStore(createTempDir("source"), false);
+        IndexShard shard = mock(IndexShard.class);
+        when(shard.store()).thenReturn(store);
+        Directory dir = store.directory();
+        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
+        int numDocs = randomIntBetween(10, 100);
+        for (int i = 0; i < numDocs; i++) {
+            Document document = new Document();
+            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
+            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
+            writer.addDocument(document);
+        }
+        writer.commit();
+        writer.close();
+        AtomicBoolean wasCancelled = new AtomicBoolean();
+        SetOnce<Runnable> cancelRecovery = new SetOnce<>();
+        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
+            @Override
+            public void receiveFileInfo(
+                List<String> phase1FileNames,
+                List<Long> phase1FileSizes,
+                List<String> phase1ExistingFileNames,
+                List<Long> phase1ExistingFileSizes,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                recoveryExecutor.execute(() -> listener.onResponse(null));
+                if (randomBoolean()) {
+                    wasCancelled.set(true);
+                    cancelRecovery.get().run();
+                }
+            }
+
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata md,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                recoveryExecutor.execute(() -> listener.onResponse(null));
+                if (rarely()) {
+                    wasCancelled.set(true);
+                    cancelRecovery.get().run();
+                }
+            }
+
+            @Override
+            public void cleanFiles(
+                int totalTranslogOps,
+                long globalCheckpoint,
+                Store.MetadataSnapshot sourceMetadata,
+                ActionListener<Void> listener
+            ) {
+                recoveryExecutor.execute(() -> listener.onResponse(null));
+                if (randomBoolean()) {
+                    wasCancelled.set(true);
+                    cancelRecovery.get().run();
+                }
+            }
+        };
+        final StartRecoveryRequest startRecoveryRequest = getStartRecoveryRequest();
+        final RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            recoveryTarget,
+            threadPool,
+            startRecoveryRequest,
+            between(1, 16),
+            between(1, 4),
+            between(1, 4)
+        ) {
+            @Override
+            void createRetentionLease(long startingSeqNo, ActionListener<RetentionLease> listener) {
+                final String leaseId = ReplicationTracker.getPeerRecoveryRetentionLeaseId(startRecoveryRequest.targetNode().getId());
+                listener.onResponse(
+                    new RetentionLease(
+                        leaseId,
+                        startingSeqNo,
+                        threadPool.absoluteTimeInMillis(),
+                        ReplicationTracker.PEER_RECOVERY_RETENTION_LEASE_SOURCE
+                    )
+                );
+            }
+        };
+        cancelRecovery.set(() -> handler.cancel("test"));
+        final StepListener<RecoverySourceHandler.SendFileResult> phase1Listener = new StepListener<>();
+        try {
+            final CountDownLatch latch = new CountDownLatch(1);
+            handler.phase1(DirectoryReader.listCommits(dir).get(0), 0, () -> 0, new LatchedActionListener<>(phase1Listener, latch), false);
+            latch.await();
+            phase1Listener.result();
+        } catch (Exception e) {
+            assertTrue(wasCancelled.get());
+            assertNotNull(ExceptionsHelper.unwrap(e, CancellableThreads.ExecutionCancelledException.class));
+        }
+        store.close();
+    }
+
+    public void testVerifySeqNoStatsWhenRecoverWithSyncId() throws Exception {
+        IndexShard shard = mock(IndexShard.class);
+        when(shard.state()).thenReturn(IndexShardState.STARTED);
+        RecoverySourceHandler handler = new LocalStorePeerRecoverySourceHandler(
+            shard,
+            new TestRecoveryTargetHandler(),
+            threadPool,
+            getStartRecoveryRequest(),
+            between(1, 16),
+            between(1, 4),
+            between(1, 4)
+        );
+
+        String syncId = UUIDs.randomBase64UUID();
+        int numDocs = between(0, 1000);
+        long localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE);
+        long maxSeqNo = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE);
+        assertTrue(
+            handler.canSkipPhase1(
+                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs),
+                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs)
+            )
+        );
+
+        AssertionError error = expectThrows(AssertionError.class, () -> {
+            long localCheckpointOnTarget = randomValueOtherThan(
+                localCheckpoint,
+                () -> randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE)
+            );
+            long maxSeqNoOnTarget = randomValueOtherThan(
+                maxSeqNo,
+                () -> randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE)
+            );
+            handler.canSkipPhase1(
+                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs),
+                newMetadataSnapshot(syncId, Long.toString(localCheckpointOnTarget), Long.toString(maxSeqNoOnTarget), numDocs)
+            );
+        });
+        assertThat(error.getMessage(), containsString("try to recover [index][1] with sync id but seq_no stats are mismatched:"));
+    }
+
+    private Store.MetadataSnapshot newMetadataSnapshot(String syncId, String localCheckpoint, String maxSeqNo, int numDocs) {
+        Map<String, String> userData = new HashMap<>();
+        userData.put(Engine.SYNC_COMMIT_ID, syncId);
+        if (localCheckpoint != null) {
+            userData.put(SequenceNumbers.LOCAL_CHECKPOINT_KEY, localCheckpoint);
+        }
+        if (maxSeqNo != null) {
+            userData.put(SequenceNumbers.LOCAL_CHECKPOINT_KEY, maxSeqNo);
+        }
+        return new Store.MetadataSnapshot(Collections.emptyMap(), userData, numDocs);
+    }
+
+    private Store newStore(Path path) throws IOException {
+        return newStore(path, true);
+    }
+
+    private Store newStore(Path path, boolean checkIndex) throws IOException {
+        BaseDirectoryWrapper baseDirectoryWrapper = LocalStorePeerRecoverySourceHandlerTests.newFSDirectory(path);
+        if (checkIndex == false) {
+            baseDirectoryWrapper.setCheckIndexOnClose(false); // don't run checkindex we might corrupt the index in these tests
+        }
+        return new Store(shardId, INDEX_SETTINGS, baseDirectoryWrapper, new DummyShardLock(shardId));
+    }
+
+    static final class FileChunkResponse {
+        final long chunkNumber;
+        final ActionListener<Void> listener;
+
+        FileChunkResponse(long chunkNumber, ActionListener<Void> listener) {
+            this.chunkNumber = chunkNumber;
+            this.listener = listener;
+        }
+    }
+
+    private List<StoreFileMetadata> generateFiles(Store store, int numFiles, IntSupplier fileSizeSupplier) throws IOException {
+        List<StoreFileMetadata> files = new ArrayList<>();
+        for (int i = 0; i < numFiles; i++) {
+            byte[] buffer = randomByteArrayOfLength(fileSizeSupplier.getAsInt());
+            CRC32 digest = new CRC32();
+            digest.update(buffer, 0, buffer.length);
+            StoreFileMetadata md = new StoreFileMetadata(
+                "test-" + i,
+                buffer.length + 8,
+                Store.digestToString(digest.getValue()),
+                org.apache.lucene.util.Version.LATEST
+            );
+            try (OutputStream out = new IndexOutputOutputStream(store.createVerifyingOutput(md.name(), md, IOContext.DEFAULT))) {
+                out.write(buffer);
+                out.write(Numbers.longToBytes(digest.getValue()));
+            }
+            store.directory().sync(Collections.singleton(md.name()));
+            files.add(md);
+        }
+        return files;
+    }
+
+    class TestRecoveryTargetHandler implements RecoveryTargetHandler {
+        @Override
+        public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Void> listener) {}
+
+        @Override
+        public void finalizeRecovery(long globalCheckpoint, long trimAboveSeqNo, ActionListener<Void> listener) {}
+
+        @Override
+        public void forceSegmentFileSync() {}
+
+        @Override
+        public void handoffPrimaryContext(ReplicationTracker.PrimaryContext primaryContext) {}
+
+        @Override
+        public void indexTranslogOperations(
+            final List<Translog.Operation> operations,
+            final int totalTranslogOps,
+            final long timestamp,
+            final long msu,
+            final RetentionLeases retentionLeases,
+            final long mappingVersion,
+            final ActionListener<Long> listener
+        ) {}
+
+        @Override
+        public void receiveFileInfo(
+            List<String> phase1FileNames,
+            List<Long> phase1FileSizes,
+            List<String> phase1ExistingFileNames,
+            List<Long> phase1ExistingFileSizes,
+            int totalTranslogOps,
+            ActionListener<Void> listener
+        ) {
+
+        }
+
+        @Override
+        public void cleanFiles(
+            int totalTranslogOps,
+            long globalCheckpoint,
+            Store.MetadataSnapshot sourceMetadata,
+            ActionListener<Void> listener
+        ) {}
+
+        @Override
+        public void writeFileChunk(
+            StoreFileMetadata fileMetadata,
+            long position,
+            BytesReference content,
+            boolean lastChunk,
+            int totalTranslogOps,
+            ActionListener<Void> listener
+        ) {}
+    }
+
+    private Translog.Snapshot newTranslogSnapshot(List<Translog.Operation> operations, List<Translog.Operation> operationsToSkip) {
+        Iterator<Translog.Operation> iterator = operations.iterator();
+        return new Translog.Snapshot() {
+            int skippedCount = 0;
+
+            @Override
+            public int totalOperations() {
+                return operations.size();
+            }
+
+            @Override
+            public int skippedOperations() {
+                return skippedCount;
+            }
+
+            @Override
+            public Translog.Operation next() {
+                while (iterator.hasNext()) {
+                    Translog.Operation op = iterator.next();
+                    if (operationsToSkip.contains(op)) {
+                        skippedCount++;
+                    } else {
+                        return op;
+                    }
+                }
+                return null;
+            }
+
+            @Override
+            public void close() {
+
+            }
+        };
+    }
+
+    private static List<Translog.Operation> generateOperations(int numOps) {
+        final List<Translog.Operation> operations = new ArrayList<>(numOps);
+        final byte[] source = "{}".getBytes(StandardCharsets.UTF_8);
+        final Set<Long> seqNos = new HashSet<>();
+        for (int i = 0; i < numOps; i++) {
+            final long seqNo = randomValueOtherThanMany(n -> seqNos.add(n) == false, OpenSearchTestCase::randomNonNegativeLong);
+            final Translog.Operation op;
+            if (randomBoolean()) {
+                op = new Translog.Index("id", seqNo, randomNonNegativeLong(), randomNonNegativeLong(), source, null, -1);
+            } else if (randomBoolean()) {
+                op = new Translog.Delete("id", seqNo, randomNonNegativeLong(), randomNonNegativeLong());
+            } else {
+                op = new Translog.NoOp(seqNo, randomNonNegativeLong(), "test");
+            }
+            operations.add(op);
+        }
+        return operations;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/recovery/PeerRecoveryTargetServiceTests.java b/server/src/test/java/org/opensearch/indices/recovery/PeerRecoveryTargetServiceTests.java
index e54f06937cad3..34f854cae56ba 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/PeerRecoveryTargetServiceTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/PeerRecoveryTargetServiceTests.java
@@ -35,7 +35,6 @@
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.PlainActionFuture;
@@ -45,10 +44,11 @@
 import org.opensearch.cluster.routing.ShardRoutingHelper;
 import org.opensearch.common.Randomness;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.engine.EngineConfigFactory;
 import org.opensearch.index.engine.NoOpEngine;
 import org.opensearch.index.mapper.SourceToParse;
@@ -65,6 +65,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.UUID;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.CyclicBarrier;
@@ -85,7 +86,7 @@ public void testWriteFileChunksConcurrently() throws Exception {
             indexDoc(sourceShard, "_doc", Integer.toString(i));
         }
         sourceShard.flush(new FlushRequest());
-        Store.MetadataSnapshot sourceSnapshot = sourceShard.store().getMetadata(null);
+        Store.MetadataSnapshot sourceSnapshot = sourceShard.store().getMetadata();
         List<StoreFileMetadata> mdFiles = new ArrayList<>();
         for (StoreFileMetadata md : sourceSnapshot) {
             mdFiles.add(md);
@@ -105,7 +106,7 @@ public void testWriteFileChunksConcurrently() throws Exception {
             receiveFileInfoFuture
         );
         receiveFileInfoFuture.actionGet();
-        List<RecoveryFileChunkRequest> requests = new ArrayList<>();
+        List<FileChunkRequest> requests = new ArrayList<>();
         long seqNo = 0;
         for (StoreFileMetadata md : mdFiles) {
             try (IndexInput in = sourceShard.store().directory().openInput(md.name(), IOContext.READONCE)) {
@@ -115,7 +116,7 @@ public void testWriteFileChunksConcurrently() throws Exception {
                     byte[] buffer = new byte[length];
                     in.readBytes(buffer, 0, length);
                     requests.add(
-                        new RecoveryFileChunkRequest(
+                        new FileChunkRequest(
                             0,
                             seqNo++,
                             sourceShard.shardId(),
@@ -132,7 +133,7 @@ public void testWriteFileChunksConcurrently() throws Exception {
             }
         }
         Randomness.shuffle(requests);
-        BlockingQueue<RecoveryFileChunkRequest> queue = new ArrayBlockingQueue<>(requests.size());
+        BlockingQueue<FileChunkRequest> queue = new ArrayBlockingQueue<>(requests.size());
         queue.addAll(requests);
         Thread[] senders = new Thread[between(1, 4)];
         CyclicBarrier barrier = new CyclicBarrier(senders.length);
@@ -140,7 +141,7 @@ public void testWriteFileChunksConcurrently() throws Exception {
             senders[i] = new Thread(() -> {
                 try {
                     barrier.await();
-                    RecoveryFileChunkRequest r;
+                    FileChunkRequest r;
                     while ((r = queue.poll()) != null) {
                         recoveryTarget.writeFileChunk(
                             r.metadata(),
@@ -148,7 +149,9 @@ public void testWriteFileChunksConcurrently() throws Exception {
                             r.content(),
                             r.lastChunk(),
                             r.totalTranslogOps(),
-                            ActionListener.wrap(ignored -> {}, e -> { throw new AssertionError(e); })
+                            ActionListener.wrap(ignored -> {}, e -> {
+                                throw new AssertionError(e);
+                            })
                         );
                     }
                 } catch (Exception e) {
@@ -180,12 +183,13 @@ private SeqNoStats populateRandomData(IndexShard shard) throws IOException {
         Randomness.shuffle(seqNos);
         for (long seqNo : seqNos) {
             shard.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 seqNo,
                 1,
                 shard.getOperationPrimaryTerm(),
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(shard.shardId().getIndexName(), UUIDs.randomBase64UUID(), new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(shard.shardId().getIndexName(), UUIDs.randomBase64UUID(), new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             if (randomInt(100) < 5) {
                 shard.flush(new FlushRequest().waitIfOngoing(true));
@@ -211,7 +215,7 @@ public void testPrepareIndexForPeerRecovery() throws Exception {
         IndexShard shard = newShard(false);
         shard.markAsRecovering("for testing", new RecoveryState(shard.routingEntry(), localNode, localNode));
         shard.prepareForIndexRecovery();
-        assertThat(shard.recoverLocallyUpToGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
+        assertThat(shard.recoverLocallyAndFetchStartSeqNo(true), equalTo(UNASSIGNED_SEQ_NO));
         assertThat(shard.recoveryState().getTranslog().totalLocal(), equalTo(RecoveryState.Translog.UNKNOWN));
         assertThat(shard.recoveryState().getTranslog().recoveredOperations(), equalTo(0));
         assertThat(shard.getLastKnownGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
@@ -239,7 +243,7 @@ public void testPrepareIndexForPeerRecovery() throws Exception {
         );
         replica.markAsRecovering("for testing", new RecoveryState(replica.routingEntry(), localNode, localNode));
         replica.prepareForIndexRecovery();
-        assertThat(replica.recoverLocallyUpToGlobalCheckpoint(), equalTo(globalCheckpoint + 1));
+        assertThat(replica.recoverLocallyAndFetchStartSeqNo(true), equalTo(globalCheckpoint + 1));
         assertThat(replica.recoveryState().getTranslog().totalLocal(), equalTo(expectedTotalLocal));
         assertThat(replica.recoveryState().getTranslog().recoveredOperations(), equalTo(expectedTotalLocal));
         assertThat(replica.getLastKnownGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
@@ -254,7 +258,7 @@ public void testPrepareIndexForPeerRecovery() throws Exception {
         replica = reinitShard(shard, ShardRoutingHelper.initWithSameId(shard.routingEntry(), RecoverySource.PeerRecoverySource.INSTANCE));
         replica.markAsRecovering("for testing", new RecoveryState(replica.routingEntry(), localNode, localNode));
         replica.prepareForIndexRecovery();
-        assertThat(replica.recoverLocallyUpToGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
+        assertThat(replica.recoverLocallyAndFetchStartSeqNo(true), equalTo(UNASSIGNED_SEQ_NO));
         assertThat(replica.recoveryState().getTranslog().totalLocal(), equalTo(RecoveryState.Translog.UNKNOWN));
         assertThat(replica.recoveryState().getTranslog().recoveredOperations(), equalTo(0));
         assertThat(replica.getLastKnownGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
@@ -276,10 +280,10 @@ public void testPrepareIndexForPeerRecovery() throws Exception {
         replica.markAsRecovering("for testing", new RecoveryState(replica.routingEntry(), localNode, localNode));
         replica.prepareForIndexRecovery();
         if (safeCommit.isPresent()) {
-            assertThat(replica.recoverLocallyUpToGlobalCheckpoint(), equalTo(safeCommit.get().localCheckpoint + 1));
+            assertThat(replica.recoverLocallyAndFetchStartSeqNo(true), equalTo(safeCommit.get().localCheckpoint + 1));
             assertThat(replica.recoveryState().getTranslog().totalLocal(), equalTo(0));
         } else {
-            assertThat(replica.recoverLocallyUpToGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
+            assertThat(replica.recoverLocallyAndFetchStartSeqNo(true), equalTo(UNASSIGNED_SEQ_NO));
             assertThat(replica.recoveryState().getTranslog().totalLocal(), equalTo(RecoveryState.Translog.UNKNOWN));
         }
         assertThat(replica.recoveryState().getStage(), equalTo(RecoveryState.Stage.TRANSLOG));
@@ -317,11 +321,12 @@ public void testClosedIndexSkipsLocalRecovery() throws Exception {
             ShardRoutingHelper.initWithSameId(shard.routingEntry(), RecoverySource.PeerRecoverySource.INSTANCE),
             indexMetadata,
             NoOpEngine::new,
-            new EngineConfigFactory(shard.indexSettings())
+            new EngineConfigFactory(shard.indexSettings()),
+            null
         );
         replica.markAsRecovering("for testing", new RecoveryState(replica.routingEntry(), localNode, localNode));
         replica.prepareForIndexRecovery();
-        assertThat(replica.recoverLocallyUpToGlobalCheckpoint(), equalTo(safeCommit.get().localCheckpoint + 1));
+        assertThat(replica.recoverLocallyAndFetchStartSeqNo(true), equalTo(safeCommit.get().localCheckpoint + 1));
         assertThat(replica.recoveryState().getTranslog().totalLocal(), equalTo(0));
         assertThat(replica.recoveryState().getTranslog().recoveredOperations(), equalTo(0));
         assertThat(replica.getLastKnownGlobalCheckpoint(), equalTo(UNASSIGNED_SEQ_NO));
@@ -348,7 +353,7 @@ public void testResetStartingSeqNoIfLastCommitCorrupted() throws Exception {
         shard = reinitShard(shard, ShardRoutingHelper.initWithSameId(shard.routingEntry(), RecoverySource.PeerRecoverySource.INSTANCE));
         shard.markAsRecovering("peer recovery", new RecoveryState(shard.routingEntry(), pNode, rNode));
         shard.prepareForIndexRecovery();
-        long startingSeqNo = shard.recoverLocallyUpToGlobalCheckpoint();
+        long startingSeqNo = shard.recoverLocallyAndFetchStartSeqNo(true);
         shard.store().markStoreCorrupted(new IOException("simulated"));
         RecoveryTarget recoveryTarget = new RecoveryTarget(shard, null, null);
         StartRecoveryRequest request = PeerRecoveryTargetService.getStartRecoveryRequest(logger, rNode, recoveryTarget, startingSeqNo);
@@ -375,7 +380,7 @@ public void testResetStartRequestIfTranslogIsCorrupted() throws Exception {
         );
         IndexShard shard = newStartedShard(false);
         final SeqNoStats seqNoStats = populateRandomData(shard);
-        shard.close("test", false);
+        shard.close("test", false, false);
         if (randomBoolean()) {
             shard.store().associateIndexWithNewTranslog(UUIDs.randomBase64UUID());
         } else if (randomBoolean()) {
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RecoveryRequestTrackerTests.java b/server/src/test/java/org/opensearch/indices/recovery/RecoveryRequestTrackerTests.java
deleted file mode 100644
index 931d36f587db8..0000000000000
--- a/server/src/test/java/org/opensearch/indices/recovery/RecoveryRequestTrackerTests.java
+++ /dev/null
@@ -1,125 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.recovery;
-
-import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.threadpool.TestThreadPool;
-
-import java.util.Collection;
-import java.util.Optional;
-import java.util.Set;
-import java.util.concurrent.ConcurrentMap;
-
-public class RecoveryRequestTrackerTests extends OpenSearchTestCase {
-
-    private TestThreadPool threadPool;
-
-    @Override
-    public void setUp() throws Exception {
-        super.setUp();
-        threadPool = new TestThreadPool(getTestName());
-    }
-
-    @Override
-    public void tearDown() throws Exception {
-        terminate(threadPool);
-        super.tearDown();
-    }
-
-    public void testIdempotencyIsEnforced() {
-        Set<Long> seqNosReturned = ConcurrentCollections.newConcurrentSet();
-        ConcurrentMap<Long, Set<PlainActionFuture<Void>>> seqToResult = ConcurrentCollections.newConcurrentMap();
-
-        RecoveryRequestTracker requestTracker = new RecoveryRequestTracker();
-
-        int numberOfRequests = randomIntBetween(100, 200);
-        for (int j = 0; j < numberOfRequests; ++j) {
-            final long seqNo = j;
-            int iterations = randomIntBetween(2, 5);
-            for (int i = 0; i < iterations; ++i) {
-                PlainActionFuture<Void> future = PlainActionFuture.newFuture();
-                Set<PlainActionFuture<Void>> set = seqToResult.computeIfAbsent(seqNo, (k) -> ConcurrentCollections.newConcurrentSet());
-                set.add(future);
-                threadPool.generic().execute(() -> {
-                    ActionListener<Void> listener = requestTracker.markReceivedAndCreateListener(seqNo, future);
-                    if (listener != null) {
-                        boolean added = seqNosReturned.add(seqNo);
-                        // Ensure that we only return 1 future per sequence number
-                        assertTrue(added);
-                        if (rarely()) {
-                            listener.onFailure(new OpenSearchException(randomAlphaOfLength(10)));
-                        } else {
-                            listener.onResponse(null);
-                        }
-                    }
-                });
-            }
-        }
-
-        seqToResult.values().stream().flatMap(Collection::stream).forEach(f -> {
-            try {
-                f.actionGet();
-            } catch (Exception e) {
-                // Ignore for now. We will assert later.
-            }
-        });
-
-        for (Set<PlainActionFuture<Void>> value : seqToResult.values()) {
-            Optional<PlainActionFuture<Void>> first = value.stream().findFirst();
-            assertTrue(first.isPresent());
-            Exception expectedException = null;
-            try {
-                first.get().actionGet();
-            } catch (Exception e) {
-                expectedException = e;
-            }
-            for (PlainActionFuture<Void> future : value) {
-                assertTrue(future.isDone());
-                if (expectedException == null) {
-                    future.actionGet();
-                } else {
-                    try {
-                        future.actionGet();
-                        fail("expected exception");
-                    } catch (Exception e) {
-                        assertEquals(expectedException.getMessage(), e.getMessage());
-                    }
-                }
-            }
-        }
-    }
-}
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RecoverySourceHandlerTests.java b/server/src/test/java/org/opensearch/indices/recovery/RecoverySourceHandlerTests.java
deleted file mode 100644
index 80326fbf2de6b..0000000000000
--- a/server/src/test/java/org/opensearch/indices/recovery/RecoverySourceHandlerTests.java
+++ /dev/null
@@ -1,1199 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.indices.recovery;
-
-import org.apache.lucene.document.Document;
-import org.apache.lucene.document.Field;
-import org.apache.lucene.document.NumericDocValuesField;
-import org.apache.lucene.document.StringField;
-import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.CorruptIndexException;
-import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.IndexCommit;
-import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
-import org.apache.lucene.index.Term;
-import org.apache.lucene.tests.store.BaseDirectoryWrapper;
-import org.apache.lucene.store.Directory;
-import org.apache.lucene.store.IOContext;
-import org.apache.lucene.util.SetOnce;
-import org.junit.After;
-import org.junit.Before;
-import org.opensearch.ExceptionsHelper;
-import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.LatchedActionListener;
-import org.opensearch.action.StepListener;
-import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.Numbers;
-import org.opensearch.common.Randomness;
-import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.concurrent.GatedCloseable;
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.lease.Releasable;
-import org.opensearch.common.lucene.store.IndexOutputOutputStream;
-import org.opensearch.common.lucene.uid.Versions;
-import org.opensearch.common.settings.ClusterSettings;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.CancellableThreads;
-import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.IndexSettings;
-import org.opensearch.index.engine.Engine;
-import org.opensearch.index.engine.RecoveryEngineException;
-import org.opensearch.index.engine.SegmentsStats;
-import org.opensearch.index.mapper.IdFieldMapper;
-import org.opensearch.index.mapper.ParseContext;
-import org.opensearch.index.mapper.ParsedDocument;
-import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.Uid;
-import org.opensearch.index.seqno.ReplicationTracker;
-import org.opensearch.index.seqno.RetentionLease;
-import org.opensearch.index.seqno.RetentionLeases;
-import org.opensearch.index.seqno.SeqNoStats;
-import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.IndexShardRelocatedException;
-import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.store.Store;
-import org.opensearch.index.store.StoreFileMetadata;
-import org.opensearch.index.translog.Translog;
-import org.opensearch.test.CorruptionUtils;
-import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.IndexSettingsModule;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.test.VersionUtils;
-import org.opensearch.threadpool.FixedExecutorBuilder;
-import org.opensearch.threadpool.TestThreadPool;
-import org.opensearch.threadpool.ThreadPool;
-
-import java.io.IOException;
-import java.io.OutputStream;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Queue;
-import java.util.Set;
-import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Executor;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicLong;
-import java.util.function.IntSupplier;
-import java.util.stream.Collectors;
-import java.util.zip.CRC32;
-
-import static java.util.Collections.emptyMap;
-import static java.util.Collections.emptySet;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.hasSize;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.anyBoolean;
-import static org.mockito.Mockito.anyString;
-import static org.mockito.Mockito.doAnswer;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-public class RecoverySourceHandlerTests extends OpenSearchTestCase {
-    private static final IndexSettings INDEX_SETTINGS = IndexSettingsModule.newIndexSettings(
-        "index",
-        Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT).build()
-    );
-    private final ShardId shardId = new ShardId(INDEX_SETTINGS.getIndex(), 1);
-    private final ClusterSettings service = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
-
-    private ThreadPool threadPool;
-    private Executor recoveryExecutor;
-
-    @Before
-    public void setUpThreadPool() {
-        if (randomBoolean()) {
-            threadPool = new TestThreadPool(getTestName());
-            recoveryExecutor = threadPool.generic();
-        } else {
-            // verify that both sending and receiving files can be completed with a single thread
-            threadPool = new TestThreadPool(
-                getTestName(),
-                new FixedExecutorBuilder(Settings.EMPTY, "recovery_executor", between(1, 16), between(16, 128), "recovery_executor")
-            );
-            recoveryExecutor = threadPool.executor("recovery_executor");
-        }
-    }
-
-    @After
-    public void tearDownThreadPool() {
-        terminate(threadPool);
-    }
-
-    public void testSendFiles() throws Throwable {
-        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        Store store = newStore(createTempDir());
-        Directory dir = store.directory();
-        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
-        int numDocs = randomIntBetween(10, 100);
-        for (int i = 0; i < numDocs; i++) {
-            Document document = new Document();
-            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
-            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
-            writer.addDocument(document);
-        }
-        writer.commit();
-        writer.close();
-
-        Store.MetadataSnapshot metadata = store.getMetadata(null);
-        List<StoreFileMetadata> metas = new ArrayList<>();
-        for (StoreFileMetadata md : metadata) {
-            metas.add(md);
-        }
-        Store targetStore = newStore(createTempDir());
-        MultiFileWriter multiFileWriter = new MultiFileWriter(targetStore, mock(RecoveryState.Index.class), "", logger, () -> {});
-        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                ActionListener.completeWith(listener, () -> {
-                    multiFileWriter.writeFileChunk(md, position, content, lastChunk);
-                    return null;
-                });
-            }
-        };
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            null,
-            new AsyncRecoveryTarget(target, recoveryExecutor),
-            threadPool,
-            request,
-            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
-            between(1, 5),
-            between(1, 5)
-        );
-        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
-        handler.sendFiles(store, metas.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
-        sendFilesFuture.actionGet();
-        Store.MetadataSnapshot targetStoreMetadata = targetStore.getMetadata(null);
-        Store.RecoveryDiff recoveryDiff = targetStoreMetadata.recoveryDiff(metadata);
-        assertEquals(metas.size(), recoveryDiff.identical.size());
-        assertEquals(0, recoveryDiff.different.size());
-        assertEquals(0, recoveryDiff.missing.size());
-        IndexReader reader = DirectoryReader.open(targetStore.directory());
-        assertEquals(numDocs, reader.maxDoc());
-        IOUtils.close(reader, store, multiFileWriter, targetStore);
-    }
-
-    public StartRecoveryRequest getStartRecoveryRequest() throws IOException {
-        Store.MetadataSnapshot metadataSnapshot = randomBoolean()
-            ? Store.MetadataSnapshot.EMPTY
-            : new Store.MetadataSnapshot(
-                Collections.emptyMap(),
-                Collections.singletonMap(Engine.HISTORY_UUID_KEY, UUIDs.randomBase64UUID()),
-                randomIntBetween(0, 100)
-            );
-        return new StartRecoveryRequest(
-            shardId,
-            null,
-            new DiscoveryNode("b", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT),
-            new DiscoveryNode("b", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT),
-            metadataSnapshot,
-            randomBoolean(),
-            randomNonNegativeLong(),
-            randomBoolean() || metadataSnapshot.getHistoryUUID() == null ? SequenceNumbers.UNASSIGNED_SEQ_NO : randomNonNegativeLong()
-        );
-    }
-
-    public void testSendSnapshotSendsOps() throws IOException {
-        final int fileChunkSizeInBytes = between(1, 4096);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        final IndexShard shard = mock(IndexShard.class);
-        when(shard.state()).thenReturn(IndexShardState.STARTED);
-        final List<Translog.Operation> operations = new ArrayList<>();
-        final int initialNumberOfDocs = randomIntBetween(10, 1000);
-        for (int i = 0; i < initialNumberOfDocs; i++) {
-            final Engine.Index index = getIndex(Integer.toString(i));
-            operations.add(new Translog.Index(index, new Engine.IndexResult(1, 1, SequenceNumbers.UNASSIGNED_SEQ_NO, true)));
-        }
-        final int numberOfDocsWithValidSequenceNumbers = randomIntBetween(10, 1000);
-        for (int i = initialNumberOfDocs; i < initialNumberOfDocs + numberOfDocsWithValidSequenceNumbers; i++) {
-            final Engine.Index index = getIndex(Integer.toString(i));
-            operations.add(new Translog.Index(index, new Engine.IndexResult(1, 1, i - initialNumberOfDocs, true)));
-        }
-        final long startingSeqNo = randomIntBetween(0, numberOfDocsWithValidSequenceNumbers - 1);
-        final long endingSeqNo = randomLongBetween(startingSeqNo, numberOfDocsWithValidSequenceNumbers - 1);
-
-        final Queue<Translog.Operation> shippedOps = ConcurrentCollections.newQueue();
-        final AtomicLong checkpointOnTarget = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        RecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
-            @Override
-            public void indexTranslogOperations(
-                List<Translog.Operation> operations,
-                int totalTranslogOps,
-                long timestamp,
-                long msu,
-                RetentionLeases retentionLeases,
-                long mappingVersion,
-                ActionListener<Long> listener
-            ) {
-                shippedOps.addAll(operations);
-                if (randomBoolean()) {
-                    checkpointOnTarget.addAndGet(between(1, 20));
-                }
-                listener.onResponse(checkpointOnTarget.get());
-            }
-        };
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic()),
-            threadPool,
-            request,
-            fileChunkSizeInBytes,
-            between(1, 10),
-            between(1, 10)
-        );
-        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> future = new PlainActionFuture<>();
-        handler.phase2(
-            startingSeqNo,
-            endingSeqNo,
-            newTranslogSnapshot(operations, Collections.emptyList()),
-            randomNonNegativeLong(),
-            randomNonNegativeLong(),
-            RetentionLeases.EMPTY,
-            randomNonNegativeLong(),
-            future
-        );
-        final int expectedOps = (int) (endingSeqNo - startingSeqNo + 1);
-        RecoverySourceHandler.SendSnapshotResult result = future.actionGet();
-        assertThat(result.sentOperations, equalTo(expectedOps));
-        List<Translog.Operation> sortedShippedOps = shippedOps.stream()
-            .sorted(Comparator.comparing(Translog.Operation::seqNo))
-            .collect(Collectors.toList());
-        assertThat(shippedOps.size(), equalTo(expectedOps));
-        for (int i = 0; i < shippedOps.size(); i++) {
-            assertThat(sortedShippedOps.get(i), equalTo(operations.get(i + (int) startingSeqNo + initialNumberOfDocs)));
-        }
-        assertThat(result.targetLocalCheckpoint, equalTo(checkpointOnTarget.get()));
-    }
-
-    public void testSendSnapshotStopOnError() throws Exception {
-        final int fileChunkSizeInBytes = between(1, 10 * 1024);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        final IndexShard shard = mock(IndexShard.class);
-        when(shard.state()).thenReturn(IndexShardState.STARTED);
-        final List<Translog.Operation> ops = new ArrayList<>();
-        for (int numOps = between(1, 256), i = 0; i < numOps; i++) {
-            final Engine.Index index = getIndex(Integer.toString(i));
-            ops.add(new Translog.Index(index, new Engine.IndexResult(1, 1, i, true)));
-        }
-        final AtomicBoolean wasFailed = new AtomicBoolean();
-        RecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
-            @Override
-            public void indexTranslogOperations(
-                List<Translog.Operation> operations,
-                int totalTranslogOps,
-                long timestamp,
-                long msu,
-                RetentionLeases retentionLeases,
-                long mappingVersion,
-                ActionListener<Long> listener
-            ) {
-                if (randomBoolean()) {
-                    listener.onResponse(SequenceNumbers.NO_OPS_PERFORMED);
-                } else {
-                    listener.onFailure(new RuntimeException("test - failed to index"));
-                    wasFailed.set(true);
-                }
-            }
-        };
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic()),
-            threadPool,
-            request,
-            fileChunkSizeInBytes,
-            between(1, 10),
-            between(1, 10)
-        );
-        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> future = new PlainActionFuture<>();
-        final long startingSeqNo = randomLongBetween(0, ops.size() - 1L);
-        final long endingSeqNo = randomLongBetween(startingSeqNo, ops.size() - 1L);
-        handler.phase2(
-            startingSeqNo,
-            endingSeqNo,
-            newTranslogSnapshot(ops, Collections.emptyList()),
-            randomNonNegativeLong(),
-            randomNonNegativeLong(),
-            RetentionLeases.EMPTY,
-            randomNonNegativeLong(),
-            future
-        );
-        if (wasFailed.get()) {
-            final RecoveryEngineException error = expectThrows(RecoveryEngineException.class, future::actionGet);
-            assertThat(error.getMessage(), equalTo("Phase[2] failed to send/replay operations"));
-            assertThat(error.getCause().getMessage(), equalTo("test - failed to index"));
-        }
-    }
-
-    public void testSendOperationsConcurrently() throws Throwable {
-        final IndexShard shard = mock(IndexShard.class);
-        when(shard.state()).thenReturn(IndexShardState.STARTED);
-        Set<Long> receivedSeqNos = ConcurrentCollections.newConcurrentSet();
-        long maxSeenAutoIdTimestamp = randomBoolean() ? -1 : randomNonNegativeLong();
-        long maxSeqNoOfUpdatesOrDeletes = randomBoolean() ? -1 : randomNonNegativeLong();
-        RetentionLeases retentionLeases = new RetentionLeases(randomNonNegativeLong(), randomNonNegativeLong(), Collections.emptySet());
-        long mappingVersion = randomNonNegativeLong();
-        AtomicLong localCheckpoint = new AtomicLong(SequenceNumbers.NO_OPS_PERFORMED);
-        int numOps = randomIntBetween(0, 1000);
-        AtomicBoolean received = new AtomicBoolean();
-        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
-            @Override
-            public void indexTranslogOperations(
-                List<Translog.Operation> operations,
-                int receivedTotalOps,
-                long receivedMaxSeenAutoIdTimestamp,
-                long receivedMaxSeqNoOfUpdatesOrDeletes,
-                RetentionLeases receivedRetentionLease,
-                long receivedMappingVersion,
-                ActionListener<Long> listener
-            ) {
-                received.set(true);
-                assertThat(receivedMaxSeenAutoIdTimestamp, equalTo(maxSeenAutoIdTimestamp));
-                assertThat(receivedMaxSeqNoOfUpdatesOrDeletes, equalTo(maxSeqNoOfUpdatesOrDeletes));
-                assertThat(receivedRetentionLease, equalTo(retentionLeases));
-                assertThat(receivedMappingVersion, equalTo(mappingVersion));
-                assertThat(receivedTotalOps, equalTo(numOps));
-                for (Translog.Operation operation : operations) {
-                    receivedSeqNos.add(operation.seqNo());
-                }
-                if (randomBoolean()) {
-                    localCheckpoint.addAndGet(randomIntBetween(1, 100));
-                }
-                listener.onResponse(localCheckpoint.get());
-            }
-        };
-
-        PlainActionFuture<RecoverySourceHandler.SendSnapshotResult> sendFuture = new PlainActionFuture<>();
-        long startingSeqNo = randomIntBetween(0, 1000);
-        long endingSeqNo = startingSeqNo + randomIntBetween(0, 10000);
-        List<Translog.Operation> operations = generateOperations(numOps);
-        Randomness.shuffle(operations);
-        List<Translog.Operation> skipOperations = randomSubsetOf(operations);
-        Translog.Snapshot snapshot = newTranslogSnapshot(operations, skipOperations);
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            new AsyncRecoveryTarget(target, recoveryExecutor),
-            threadPool,
-            getStartRecoveryRequest(),
-            between(1, 10 * 1024),
-            between(1, 5),
-            between(1, 5)
-        );
-        handler.phase2(
-            startingSeqNo,
-            endingSeqNo,
-            snapshot,
-            maxSeenAutoIdTimestamp,
-            maxSeqNoOfUpdatesOrDeletes,
-            retentionLeases,
-            mappingVersion,
-            sendFuture
-        );
-        RecoverySourceHandler.SendSnapshotResult sendSnapshotResult = sendFuture.actionGet();
-        assertTrue(received.get());
-        assertThat(sendSnapshotResult.targetLocalCheckpoint, equalTo(localCheckpoint.get()));
-        assertThat(sendSnapshotResult.sentOperations, equalTo(receivedSeqNos.size()));
-        Set<Long> sentSeqNos = new HashSet<>();
-        for (Translog.Operation op : operations) {
-            if (startingSeqNo <= op.seqNo() && op.seqNo() <= endingSeqNo && skipOperations.contains(op) == false) {
-                sentSeqNos.add(op.seqNo());
-            }
-        }
-        assertThat(receivedSeqNos, equalTo(sentSeqNos));
-    }
-
-    private Engine.Index getIndex(final String id) {
-        final ParseContext.Document document = new ParseContext.Document();
-        document.add(new TextField("test", "test", Field.Store.YES));
-        final Field idField = new Field("_id", Uid.encodeId(id), IdFieldMapper.Defaults.FIELD_TYPE);
-        final Field versionField = new NumericDocValuesField("_version", Versions.MATCH_ANY);
-        final SeqNoFieldMapper.SequenceIDFields seqID = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
-        document.add(idField);
-        document.add(versionField);
-        document.add(seqID.seqNo);
-        document.add(seqID.seqNoDocValue);
-        document.add(seqID.primaryTerm);
-        final BytesReference source = new BytesArray(new byte[] { 1 });
-        final ParsedDocument doc = new ParsedDocument(
-            versionField,
-            seqID,
-            id,
-            null,
-            Arrays.asList(document),
-            source,
-            XContentType.JSON,
-            null
-        );
-        return new Engine.Index(new Term("_id", Uid.encodeId(doc.id())), randomNonNegativeLong(), doc);
-    }
-
-    public void testHandleCorruptedIndexOnSendSendFiles() throws Throwable {
-        Settings settings = Settings.builder()
-            .put("indices.recovery.concurrent_streams", 1)
-            .put("indices.recovery.concurrent_small_file_streams", 1)
-            .build();
-        final RecoverySettings recoverySettings = new RecoverySettings(settings, service);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        Path tempDir = createTempDir();
-        Store store = newStore(tempDir, false);
-        AtomicBoolean failedEngine = new AtomicBoolean(false);
-        Directory dir = store.directory();
-        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
-        int numDocs = randomIntBetween(10, 100);
-        for (int i = 0; i < numDocs; i++) {
-            Document document = new Document();
-            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
-            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
-            writer.addDocument(document);
-        }
-        writer.commit();
-        writer.close();
-
-        Store.MetadataSnapshot metadata = store.getMetadata(null);
-        List<StoreFileMetadata> metas = new ArrayList<>();
-        for (StoreFileMetadata md : metadata) {
-            metas.add(md);
-        }
-
-        CorruptionUtils.corruptFile(
-            random(),
-            FileSystemUtils.files(
-                tempDir,
-                (p) -> (p.getFileName().toString().equals("write.lock") || p.getFileName().toString().startsWith("extra")) == false
-            )
-        );
-        Store targetStore = newStore(createTempDir(), false);
-        MultiFileWriter multiFileWriter = new MultiFileWriter(targetStore, mock(RecoveryState.Index.class), "", logger, () -> {});
-        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                ActionListener.completeWith(listener, () -> {
-                    multiFileWriter.writeFileChunk(md, position, content, lastChunk);
-                    return null;
-                });
-            }
-        };
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            null,
-            new AsyncRecoveryTarget(target, recoveryExecutor),
-            threadPool,
-            request,
-            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
-            between(1, 8),
-            between(1, 8)
-        ) {
-            @Override
-            protected void failEngine(IOException cause) {
-                assertFalse(failedEngine.get());
-                failedEngine.set(true);
-            }
-        };
-        SetOnce<Exception> sendFilesError = new SetOnce<>();
-        CountDownLatch latch = new CountDownLatch(1);
-        handler.sendFiles(
-            store,
-            metas.toArray(new StoreFileMetadata[0]),
-            () -> 0,
-            new LatchedActionListener<>(ActionListener.wrap(r -> sendFilesError.set(null), e -> sendFilesError.set(e)), latch)
-        );
-        latch.await();
-        assertThat(sendFilesError.get(), instanceOf(IOException.class));
-        assertNotNull(ExceptionsHelper.unwrapCorruption(sendFilesError.get()));
-        assertTrue(failedEngine.get());
-        // ensure all chunk requests have been completed; otherwise some files on the target are left open.
-        IOUtils.close(() -> terminate(threadPool), () -> threadPool = null);
-        IOUtils.close(store, multiFileWriter, targetStore);
-    }
-
-    public void testHandleExceptionOnSendFiles() throws Throwable {
-        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        Path tempDir = createTempDir();
-        Store store = newStore(tempDir, false);
-        AtomicBoolean failedEngine = new AtomicBoolean(false);
-        Directory dir = store.directory();
-        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
-        int numDocs = randomIntBetween(10, 100);
-        for (int i = 0; i < numDocs; i++) {
-            Document document = new Document();
-            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
-            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
-            writer.addDocument(document);
-        }
-        writer.commit();
-        writer.close();
-
-        Store.MetadataSnapshot metadata = store.getMetadata(null);
-        List<StoreFileMetadata> metas = new ArrayList<>();
-        for (StoreFileMetadata md : metadata) {
-            metas.add(md);
-        }
-        final boolean throwCorruptedIndexException = randomBoolean();
-        RecoveryTargetHandler target = new TestRecoveryTargetHandler() {
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                if (throwCorruptedIndexException) {
-                    listener.onFailure(new RuntimeException(new CorruptIndexException("foo", "bar")));
-                } else {
-                    listener.onFailure(new RuntimeException("boom"));
-                }
-            }
-        };
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            null,
-            new AsyncRecoveryTarget(target, recoveryExecutor),
-            threadPool,
-            request,
-            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
-            between(1, 10),
-            between(1, 4)
-        ) {
-            @Override
-            protected void failEngine(IOException cause) {
-                assertFalse(failedEngine.get());
-                failedEngine.set(true);
-            }
-        };
-        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
-        handler.sendFiles(store, metas.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
-        Exception ex = expectThrows(Exception.class, sendFilesFuture::actionGet);
-        final IOException unwrappedCorruption = ExceptionsHelper.unwrapCorruption(ex);
-        if (throwCorruptedIndexException) {
-            assertNotNull(unwrappedCorruption);
-            assertEquals(ex.getMessage(), "[File corruption occurred on recovery but checksums are ok]");
-        } else {
-            assertNull(unwrappedCorruption);
-            assertEquals(ex.getMessage(), "boom");
-        }
-        assertFalse(failedEngine.get());
-        IOUtils.close(store);
-    }
-
-    public void testThrowExceptionOnPrimaryRelocatedBeforePhase1Started() throws IOException {
-        final RecoverySettings recoverySettings = new RecoverySettings(Settings.EMPTY, service);
-        final StartRecoveryRequest request = getStartRecoveryRequest();
-        final IndexShard shard = mock(IndexShard.class);
-        when(shard.seqNoStats()).thenReturn(mock(SeqNoStats.class));
-        when(shard.segmentStats(anyBoolean(), anyBoolean())).thenReturn(mock(SegmentsStats.class));
-        when(shard.isRelocatedPrimary()).thenReturn(true);
-        when(shard.acquireSafeIndexCommit()).thenReturn(mock(GatedCloseable.class));
-        doAnswer(invocation -> {
-            ((ActionListener<Releasable>) invocation.getArguments()[0]).onResponse(() -> {});
-            return null;
-        }).when(shard).acquirePrimaryOperationPermit(any(), anyString(), any());
-
-        final IndexMetadata.Builder indexMetadata = IndexMetadata.builder("test")
-            .settings(
-                Settings.builder()
-                    .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, between(0, 5))
-                    .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, between(1, 5))
-                    .put(IndexMetadata.SETTING_VERSION_CREATED, VersionUtils.randomVersion(random()))
-                    .put(IndexMetadata.SETTING_INDEX_UUID, UUIDs.randomBase64UUID(random()))
-            );
-        if (randomBoolean()) {
-            indexMetadata.state(IndexMetadata.State.CLOSE);
-        }
-        when(shard.indexSettings()).thenReturn(new IndexSettings(indexMetadata.build(), Settings.EMPTY));
-
-        final AtomicBoolean phase1Called = new AtomicBoolean();
-        final AtomicBoolean prepareTargetForTranslogCalled = new AtomicBoolean();
-        final AtomicBoolean phase2Called = new AtomicBoolean();
-        final RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            mock(RecoveryTargetHandler.class),
-            threadPool,
-            request,
-            Math.toIntExact(recoverySettings.getChunkSize().getBytes()),
-            between(1, 8),
-            between(1, 8)
-        ) {
-
-            @Override
-            void phase1(IndexCommit snapshot, long startingSeqNo, IntSupplier translogOps, ActionListener<SendFileResult> listener) {
-                phase1Called.set(true);
-                super.phase1(snapshot, startingSeqNo, translogOps, listener);
-            }
-
-            @Override
-            void prepareTargetForTranslog(int totalTranslogOps, ActionListener<TimeValue> listener) {
-                prepareTargetForTranslogCalled.set(true);
-                super.prepareTargetForTranslog(totalTranslogOps, listener);
-            }
-
-            @Override
-            void phase2(
-                long startingSeqNo,
-                long endingSeqNo,
-                Translog.Snapshot snapshot,
-                long maxSeenAutoIdTimestamp,
-                long maxSeqNoOfUpdatesOrDeletes,
-                RetentionLeases retentionLeases,
-                long mappingVersion,
-                ActionListener<SendSnapshotResult> listener
-            ) throws IOException {
-                phase2Called.set(true);
-                super.phase2(
-                    startingSeqNo,
-                    endingSeqNo,
-                    snapshot,
-                    maxSeenAutoIdTimestamp,
-                    maxSeqNoOfUpdatesOrDeletes,
-                    retentionLeases,
-                    mappingVersion,
-                    listener
-                );
-            }
-
-        };
-        PlainActionFuture<RecoveryResponse> future = new PlainActionFuture<>();
-        expectThrows(IndexShardRelocatedException.class, () -> {
-            handler.recoverToTarget(future);
-            future.actionGet();
-        });
-        assertFalse(phase1Called.get());
-        assertFalse(prepareTargetForTranslogCalled.get());
-        assertFalse(phase2Called.get());
-    }
-
-    public void testCancellationsDoesNotLeakPrimaryPermits() throws Exception {
-        final CancellableThreads cancellableThreads = new CancellableThreads();
-        final IndexShard shard = mock(IndexShard.class);
-        final AtomicBoolean freed = new AtomicBoolean(true);
-        when(shard.isRelocatedPrimary()).thenReturn(false);
-        doAnswer(invocation -> {
-            freed.set(false);
-            ((ActionListener<Releasable>) invocation.getArguments()[0]).onResponse(() -> freed.set(true));
-            return null;
-        }).when(shard).acquirePrimaryOperationPermit(any(), anyString(), any());
-
-        Thread cancelingThread = new Thread(() -> cancellableThreads.cancel("test"));
-        cancelingThread.start();
-        try {
-            RecoverySourceHandler.runUnderPrimaryPermit(() -> {}, "test", shard, cancellableThreads, logger);
-        } catch (CancellableThreads.ExecutionCancelledException e) {
-            // expected.
-        }
-        cancelingThread.join();
-        // we have to use assert busy as we may be interrupted while acquiring the permit, if so we want to check
-        // that the permit is released.
-        assertBusy(() -> assertTrue(freed.get()));
-    }
-
-    public void testSendFileChunksConcurrently() throws Exception {
-        final IndexShard shard = mock(IndexShard.class);
-        when(shard.state()).thenReturn(IndexShardState.STARTED);
-        final List<FileChunkResponse> unrepliedChunks = new CopyOnWriteArrayList<>();
-        final AtomicInteger sentChunks = new AtomicInteger();
-        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
-            final AtomicLong chunkNumberGenerator = new AtomicLong();
-
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                final long chunkNumber = chunkNumberGenerator.getAndIncrement();
-                logger.info("--> write chunk name={} seq={}, position={}", md.name(), chunkNumber, position);
-                unrepliedChunks.add(new FileChunkResponse(chunkNumber, listener));
-                sentChunks.incrementAndGet();
-            }
-        };
-        final int maxConcurrentChunks = between(1, 8);
-        final int chunkSize = between(1, 32);
-        final RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            recoveryTarget,
-            threadPool,
-            getStartRecoveryRequest(),
-            chunkSize,
-            maxConcurrentChunks,
-            between(1, 10)
-        );
-        Store store = newStore(createTempDir(), false);
-        List<StoreFileMetadata> files = generateFiles(store, between(1, 10), () -> between(1, chunkSize * 20));
-        int totalChunks = files.stream().mapToInt(md -> ((int) md.length() + chunkSize - 1) / chunkSize).sum();
-        PlainActionFuture<Void> sendFilesFuture = new PlainActionFuture<>();
-        handler.sendFiles(store, files.toArray(new StoreFileMetadata[0]), () -> 0, sendFilesFuture);
-        assertBusy(() -> {
-            assertThat(sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks)));
-            assertThat(unrepliedChunks, hasSize(sentChunks.get()));
-        });
-
-        List<FileChunkResponse> ackedChunks = new ArrayList<>();
-        while (sentChunks.get() < totalChunks || unrepliedChunks.isEmpty() == false) {
-            List<FileChunkResponse> chunksToAck = randomSubsetOf(between(1, unrepliedChunks.size()), unrepliedChunks);
-            unrepliedChunks.removeAll(chunksToAck);
-            ackedChunks.addAll(chunksToAck);
-            ackedChunks.sort(Comparator.comparing(c -> c.chunkNumber));
-            int checkpoint = -1;
-            for (int i = 0; i < ackedChunks.size(); i++) {
-                if (i != ackedChunks.get(i).chunkNumber) {
-                    break;
-                } else {
-                    checkpoint = i;
-                }
-            }
-            int chunksToSend = Math.min(
-                totalChunks - sentChunks.get(),                             // limited by the remaining chunks
-                maxConcurrentChunks - (sentChunks.get() - 1 - checkpoint)
-            ); // limited by the buffering chunks
-
-            int expectedSentChunks = sentChunks.get() + chunksToSend;
-            int expectedUnrepliedChunks = unrepliedChunks.size() + chunksToSend;
-            chunksToAck.forEach(c -> c.listener.onResponse(null));
-            assertBusy(() -> {
-                assertThat(sentChunks.get(), equalTo(expectedSentChunks));
-                assertThat(unrepliedChunks, hasSize(expectedUnrepliedChunks));
-            });
-        }
-        sendFilesFuture.actionGet();
-        store.close();
-    }
-
-    public void testSendFileChunksStopOnError() throws Exception {
-        final List<FileChunkResponse> unrepliedChunks = new CopyOnWriteArrayList<>();
-        final AtomicInteger sentChunks = new AtomicInteger();
-        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
-            final AtomicLong chunkNumberGenerator = new AtomicLong();
-
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                final long chunkNumber = chunkNumberGenerator.getAndIncrement();
-                logger.info("--> write chunk name={} seq={}, position={}", md.name(), chunkNumber, position);
-                unrepliedChunks.add(new FileChunkResponse(chunkNumber, listener));
-                sentChunks.incrementAndGet();
-            }
-        };
-        final int maxConcurrentChunks = between(1, 4);
-        final int chunkSize = between(1, 16);
-        final RecoverySourceHandler handler = new RecoverySourceHandler(
-            null,
-            new AsyncRecoveryTarget(recoveryTarget, recoveryExecutor),
-            threadPool,
-            getStartRecoveryRequest(),
-            chunkSize,
-            maxConcurrentChunks,
-            between(1, 5)
-        );
-        Store store = newStore(createTempDir(), false);
-        List<StoreFileMetadata> files = generateFiles(store, between(1, 10), () -> between(1, chunkSize * 20));
-        int totalChunks = files.stream().mapToInt(md -> ((int) md.length() + chunkSize - 1) / chunkSize).sum();
-        SetOnce<Exception> sendFilesError = new SetOnce<>();
-        CountDownLatch sendFilesLatch = new CountDownLatch(1);
-        handler.sendFiles(
-            store,
-            files.toArray(new StoreFileMetadata[0]),
-            () -> 0,
-            new LatchedActionListener<>(ActionListener.wrap(r -> sendFilesError.set(null), e -> sendFilesError.set(e)), sendFilesLatch)
-        );
-        assertBusy(() -> assertThat(sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks))));
-        List<FileChunkResponse> failedChunks = randomSubsetOf(between(1, unrepliedChunks.size()), unrepliedChunks);
-        CountDownLatch replyLatch = new CountDownLatch(failedChunks.size());
-        failedChunks.forEach(c -> {
-            c.listener.onFailure(new IllegalStateException("test chunk exception"));
-            replyLatch.countDown();
-        });
-        replyLatch.await();
-        unrepliedChunks.removeAll(failedChunks);
-        unrepliedChunks.forEach(c -> {
-            if (randomBoolean()) {
-                c.listener.onFailure(new RuntimeException("test"));
-            } else {
-                c.listener.onResponse(null);
-            }
-        });
-        sendFilesLatch.await();
-        assertThat(sendFilesError.get(), instanceOf(IllegalStateException.class));
-        assertThat(sendFilesError.get().getMessage(), containsString("test chunk exception"));
-        assertThat("no more chunks should be sent", sentChunks.get(), equalTo(Math.min(totalChunks, maxConcurrentChunks)));
-        store.close();
-    }
-
-    public void testCancelRecoveryDuringPhase1() throws Exception {
-        Store store = newStore(createTempDir("source"), false);
-        IndexShard shard = mock(IndexShard.class);
-        when(shard.store()).thenReturn(store);
-        Directory dir = store.directory();
-        RandomIndexWriter writer = new RandomIndexWriter(random(), dir, newIndexWriterConfig());
-        int numDocs = randomIntBetween(10, 100);
-        for (int i = 0; i < numDocs; i++) {
-            Document document = new Document();
-            document.add(new StringField("id", Integer.toString(i), Field.Store.YES));
-            document.add(newField("field", randomUnicodeOfCodepointLengthBetween(1, 10), TextField.TYPE_STORED));
-            writer.addDocument(document);
-        }
-        writer.commit();
-        writer.close();
-        AtomicBoolean wasCancelled = new AtomicBoolean();
-        SetOnce<Runnable> cancelRecovery = new SetOnce<>();
-        final TestRecoveryTargetHandler recoveryTarget = new TestRecoveryTargetHandler() {
-            @Override
-            public void receiveFileInfo(
-                List<String> phase1FileNames,
-                List<Long> phase1FileSizes,
-                List<String> phase1ExistingFileNames,
-                List<Long> phase1ExistingFileSizes,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                recoveryExecutor.execute(() -> listener.onResponse(null));
-                if (randomBoolean()) {
-                    wasCancelled.set(true);
-                    cancelRecovery.get().run();
-                }
-            }
-
-            @Override
-            public void writeFileChunk(
-                StoreFileMetadata md,
-                long position,
-                BytesReference content,
-                boolean lastChunk,
-                int totalTranslogOps,
-                ActionListener<Void> listener
-            ) {
-                recoveryExecutor.execute(() -> listener.onResponse(null));
-                if (rarely()) {
-                    wasCancelled.set(true);
-                    cancelRecovery.get().run();
-                }
-            }
-
-            @Override
-            public void cleanFiles(
-                int totalTranslogOps,
-                long globalCheckpoint,
-                Store.MetadataSnapshot sourceMetadata,
-                ActionListener<Void> listener
-            ) {
-                recoveryExecutor.execute(() -> listener.onResponse(null));
-                if (randomBoolean()) {
-                    wasCancelled.set(true);
-                    cancelRecovery.get().run();
-                }
-            }
-        };
-        final StartRecoveryRequest startRecoveryRequest = getStartRecoveryRequest();
-        final RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            recoveryTarget,
-            threadPool,
-            startRecoveryRequest,
-            between(1, 16),
-            between(1, 4),
-            between(1, 4)
-        ) {
-            @Override
-            void createRetentionLease(long startingSeqNo, ActionListener<RetentionLease> listener) {
-                final String leaseId = ReplicationTracker.getPeerRecoveryRetentionLeaseId(startRecoveryRequest.targetNode().getId());
-                listener.onResponse(
-                    new RetentionLease(
-                        leaseId,
-                        startingSeqNo,
-                        threadPool.absoluteTimeInMillis(),
-                        ReplicationTracker.PEER_RECOVERY_RETENTION_LEASE_SOURCE
-                    )
-                );
-            }
-        };
-        cancelRecovery.set(() -> handler.cancel("test"));
-        final StepListener<RecoverySourceHandler.SendFileResult> phase1Listener = new StepListener<>();
-        try {
-            final CountDownLatch latch = new CountDownLatch(1);
-            handler.phase1(DirectoryReader.listCommits(dir).get(0), 0, () -> 0, new LatchedActionListener<>(phase1Listener, latch));
-            latch.await();
-            phase1Listener.result();
-        } catch (Exception e) {
-            assertTrue(wasCancelled.get());
-            assertNotNull(ExceptionsHelper.unwrap(e, CancellableThreads.ExecutionCancelledException.class));
-        }
-        store.close();
-    }
-
-    public void testVerifySeqNoStatsWhenRecoverWithSyncId() throws Exception {
-        IndexShard shard = mock(IndexShard.class);
-        when(shard.state()).thenReturn(IndexShardState.STARTED);
-        RecoverySourceHandler handler = new RecoverySourceHandler(
-            shard,
-            new TestRecoveryTargetHandler(),
-            threadPool,
-            getStartRecoveryRequest(),
-            between(1, 16),
-            between(1, 4),
-            between(1, 4)
-        );
-
-        String syncId = UUIDs.randomBase64UUID();
-        int numDocs = between(0, 1000);
-        long localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE);
-        long maxSeqNo = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE);
-        assertTrue(
-            handler.canSkipPhase1(
-                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs),
-                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs)
-            )
-        );
-
-        AssertionError error = expectThrows(AssertionError.class, () -> {
-            long localCheckpointOnTarget = randomValueOtherThan(
-                localCheckpoint,
-                () -> randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE)
-            );
-            long maxSeqNoOnTarget = randomValueOtherThan(
-                maxSeqNo,
-                () -> randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, Long.MAX_VALUE)
-            );
-            handler.canSkipPhase1(
-                newMetadataSnapshot(syncId, Long.toString(localCheckpoint), Long.toString(maxSeqNo), numDocs),
-                newMetadataSnapshot(syncId, Long.toString(localCheckpointOnTarget), Long.toString(maxSeqNoOnTarget), numDocs)
-            );
-        });
-        assertThat(error.getMessage(), containsString("try to recover [index][1] with sync id but seq_no stats are mismatched:"));
-    }
-
-    private Store.MetadataSnapshot newMetadataSnapshot(String syncId, String localCheckpoint, String maxSeqNo, int numDocs) {
-        Map<String, String> userData = new HashMap<>();
-        userData.put(Engine.SYNC_COMMIT_ID, syncId);
-        if (localCheckpoint != null) {
-            userData.put(SequenceNumbers.LOCAL_CHECKPOINT_KEY, localCheckpoint);
-        }
-        if (maxSeqNo != null) {
-            userData.put(SequenceNumbers.LOCAL_CHECKPOINT_KEY, maxSeqNo);
-        }
-        return new Store.MetadataSnapshot(Collections.emptyMap(), userData, numDocs);
-    }
-
-    private Store newStore(Path path) throws IOException {
-        return newStore(path, true);
-    }
-
-    private Store newStore(Path path, boolean checkIndex) throws IOException {
-        BaseDirectoryWrapper baseDirectoryWrapper = RecoverySourceHandlerTests.newFSDirectory(path);
-        if (checkIndex == false) {
-            baseDirectoryWrapper.setCheckIndexOnClose(false); // don't run checkindex we might corrupt the index in these tests
-        }
-        return new Store(shardId, INDEX_SETTINGS, baseDirectoryWrapper, new DummyShardLock(shardId));
-    }
-
-    static final class FileChunkResponse {
-        final long chunkNumber;
-        final ActionListener<Void> listener;
-
-        FileChunkResponse(long chunkNumber, ActionListener<Void> listener) {
-            this.chunkNumber = chunkNumber;
-            this.listener = listener;
-        }
-    }
-
-    private List<StoreFileMetadata> generateFiles(Store store, int numFiles, IntSupplier fileSizeSupplier) throws IOException {
-        List<StoreFileMetadata> files = new ArrayList<>();
-        for (int i = 0; i < numFiles; i++) {
-            byte[] buffer = randomByteArrayOfLength(fileSizeSupplier.getAsInt());
-            CRC32 digest = new CRC32();
-            digest.update(buffer, 0, buffer.length);
-            StoreFileMetadata md = new StoreFileMetadata(
-                "test-" + i,
-                buffer.length + 8,
-                Store.digestToString(digest.getValue()),
-                org.apache.lucene.util.Version.LATEST
-            );
-            try (OutputStream out = new IndexOutputOutputStream(store.createVerifyingOutput(md.name(), md, IOContext.DEFAULT))) {
-                out.write(buffer);
-                out.write(Numbers.longToBytes(digest.getValue()));
-            }
-            store.directory().sync(Collections.singleton(md.name()));
-            files.add(md);
-        }
-        return files;
-    }
-
-    class TestRecoveryTargetHandler implements RecoveryTargetHandler {
-        @Override
-        public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Void> listener) {}
-
-        @Override
-        public void finalizeRecovery(long globalCheckpoint, long trimAboveSeqNo, ActionListener<Void> listener) {}
-
-        @Override
-        public void handoffPrimaryContext(ReplicationTracker.PrimaryContext primaryContext) {}
-
-        @Override
-        public void indexTranslogOperations(
-            final List<Translog.Operation> operations,
-            final int totalTranslogOps,
-            final long timestamp,
-            final long msu,
-            final RetentionLeases retentionLeases,
-            final long mappingVersion,
-            final ActionListener<Long> listener
-        ) {}
-
-        @Override
-        public void receiveFileInfo(
-            List<String> phase1FileNames,
-            List<Long> phase1FileSizes,
-            List<String> phase1ExistingFileNames,
-            List<Long> phase1ExistingFileSizes,
-            int totalTranslogOps,
-            ActionListener<Void> listener
-        ) {
-
-        }
-
-        @Override
-        public void cleanFiles(
-            int totalTranslogOps,
-            long globalCheckpoint,
-            Store.MetadataSnapshot sourceMetadata,
-            ActionListener<Void> listener
-        ) {}
-
-        @Override
-        public void writeFileChunk(
-            StoreFileMetadata fileMetadata,
-            long position,
-            BytesReference content,
-            boolean lastChunk,
-            int totalTranslogOps,
-            ActionListener<Void> listener
-        ) {}
-    }
-
-    private Translog.Snapshot newTranslogSnapshot(List<Translog.Operation> operations, List<Translog.Operation> operationsToSkip) {
-        Iterator<Translog.Operation> iterator = operations.iterator();
-        return new Translog.Snapshot() {
-            int skippedCount = 0;
-
-            @Override
-            public int totalOperations() {
-                return operations.size();
-            }
-
-            @Override
-            public int skippedOperations() {
-                return skippedCount;
-            }
-
-            @Override
-            public Translog.Operation next() {
-                while (iterator.hasNext()) {
-                    Translog.Operation op = iterator.next();
-                    if (operationsToSkip.contains(op)) {
-                        skippedCount++;
-                    } else {
-                        return op;
-                    }
-                }
-                return null;
-            }
-
-            @Override
-            public void close() {
-
-            }
-        };
-    }
-
-    private static List<Translog.Operation> generateOperations(int numOps) {
-        final List<Translog.Operation> operations = new ArrayList<>(numOps);
-        final byte[] source = "{}".getBytes(StandardCharsets.UTF_8);
-        final Set<Long> seqNos = new HashSet<>();
-        for (int i = 0; i < numOps; i++) {
-            final long seqNo = randomValueOtherThanMany(n -> seqNos.add(n) == false, OpenSearchTestCase::randomNonNegativeLong);
-            final Translog.Operation op;
-            if (randomBoolean()) {
-                op = new Translog.Index("id", seqNo, randomNonNegativeLong(), randomNonNegativeLong(), source, null, -1);
-            } else if (randomBoolean()) {
-                op = new Translog.Delete("id", seqNo, randomNonNegativeLong(), randomNonNegativeLong());
-            } else {
-                op = new Translog.NoOp(seqNo, randomNonNegativeLong(), "test");
-            }
-            operations.add(op);
-        }
-        return operations;
-    }
-}
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RecoveryStatusTests.java b/server/src/test/java/org/opensearch/indices/recovery/RecoveryStatusTests.java
index 73caa611dbcdb..3038d11e6ad91 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/RecoveryStatusTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/RecoveryStatusTests.java
@@ -94,7 +94,7 @@ public void testRenameTempFiles() throws IOException {
             }
         }
         assertNotNull(expectedFile);
-        indexShard.close("foo", false);// we have to close it here otherwise rename fails since the write.lock is held by the engine
+        indexShard.close("foo", false, false);// we have to close it here otherwise rename fails since the write.lock is held by the engine
         multiFileWriter.renameAllTempFiles();
         strings = Sets.newHashSet(indexShard.store().directory().listAll());
         assertTrue(strings.toString(), strings.contains("foo.bar"));
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RecoveryTargetTests.java b/server/src/test/java/org/opensearch/indices/recovery/RecoveryTargetTests.java
index 5d0d9bca8b3fb..aac715cca095e 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/RecoveryTargetTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/RecoveryTargetTests.java
@@ -38,15 +38,15 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.recovery.RecoveryState.FileDetail;
-import org.opensearch.indices.recovery.RecoveryState.Index;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.recovery.RecoveryState.Stage;
-import org.opensearch.indices.recovery.RecoveryState.Timer;
 import org.opensearch.indices.recovery.RecoveryState.Translog;
 import org.opensearch.indices.recovery.RecoveryState.VerifyIndex;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex.FileMetadata;
+import org.opensearch.indices.replication.common.ReplicationTimer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -63,9 +63,7 @@
 import static org.hamcrest.Matchers.closeTo;
 import static org.hamcrest.Matchers.either;
 import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.startsWith;
 
@@ -124,77 +122,86 @@ public void run() {
         }
     }
 
-    public void testTimers() throws Throwable {
-        final Timer timer;
-        Streamer<Timer> streamer;
+    public void testTimer() throws Throwable {
         AtomicBoolean stop = new AtomicBoolean();
-        if (randomBoolean()) {
-            timer = new Timer();
-            streamer = new Streamer<Timer>(stop, timer) {
-                @Override
-                Timer createObj(StreamInput in) throws IOException {
-                    return new Timer(in);
-                }
-            };
-        } else if (randomBoolean()) {
-            timer = new Index();
-            streamer = new Streamer<Timer>(stop, timer) {
-                @Override
-                Timer createObj(StreamInput in) throws IOException {
-                    return new Index(in);
-                }
-            };
-        } else if (randomBoolean()) {
-            timer = new VerifyIndex();
-            streamer = new Streamer<Timer>(stop, timer) {
-                @Override
-                Timer createObj(StreamInput in) throws IOException {
-                    return new VerifyIndex(in);
-                }
-            };
-        } else {
-            timer = new Translog();
-            streamer = new Streamer<Timer>(stop, timer) {
-                @Override
-                Timer createObj(StreamInput in) throws IOException {
-                    return new Translog(in);
-                }
-            };
-        }
+        final ReplicationTimer timer = new ReplicationTimer();
+        Streamer<ReplicationTimer> streamer = new Streamer<>(stop, timer) {
+            @Override
+            ReplicationTimer createObj(StreamInput in) throws IOException {
+                return new ReplicationTimer(in);
+            }
+        };
+        doTimerTest(timer, streamer);
+    }
 
+    public void testIndexTimer() throws Throwable {
+        AtomicBoolean stop = new AtomicBoolean();
+        ReplicationLuceneIndex index = new ReplicationLuceneIndex();
+        Streamer<ReplicationLuceneIndex> streamer = new Streamer<>(stop, index) {
+            @Override
+            ReplicationLuceneIndex createObj(StreamInput in) throws IOException {
+                return new ReplicationLuceneIndex(in);
+            }
+        };
+        doTimerTest(index, streamer);
+    }
+
+    public void testVerifyIndexTimer() throws Throwable {
+        AtomicBoolean stop = new AtomicBoolean();
+        VerifyIndex verifyIndex = new VerifyIndex();
+        Streamer<VerifyIndex> streamer = new Streamer<>(stop, verifyIndex) {
+            @Override
+            VerifyIndex createObj(StreamInput in) throws IOException {
+                return new VerifyIndex(in);
+            }
+        };
+        doTimerTest(verifyIndex, streamer);
+    }
+
+    public void testTranslogTimer() throws Throwable {
+        AtomicBoolean stop = new AtomicBoolean();
+        Translog translog = new Translog();
+        Streamer<Translog> streamer = new Streamer<>(stop, translog) {
+            @Override
+            Translog createObj(StreamInput in) throws IOException {
+                return new Translog(in);
+            }
+        };
+        doTimerTest(translog, streamer);
+    }
+
+    private void doTimerTest(ReplicationTimer timer, Streamer<? extends ReplicationTimer> streamer) throws Exception {
         timer.start();
-        assertThat(timer.startTime(), greaterThan(0L));
-        assertThat(timer.stopTime(), equalTo(0L));
-        Timer lastRead = streamer.serializeDeserialize();
+        assertTrue(timer.startTime() > 0);
+        assertEquals(0, timer.stopTime());
+        ReplicationTimer lastRead = streamer.serializeDeserialize();
         final long time = lastRead.time();
-        assertThat(time, lessThanOrEqualTo(timer.time()));
-        assertBusy(() -> assertThat("timer timer should progress compared to captured one ", time, lessThan(timer.time())));
-        assertThat("captured time shouldn't change", lastRead.time(), equalTo(time));
+        assertBusy(() -> assertTrue("timer timer should progress compared to captured one ", time < timer.time()));
+        assertEquals("captured time shouldn't change", time, lastRead.time());
 
-        if (randomBoolean()) {
-            timer.stop();
-            assertThat(timer.stopTime(), greaterThanOrEqualTo(timer.startTime()));
-            assertThat(timer.time(), greaterThan(0L));
-            lastRead = streamer.serializeDeserialize();
-            assertThat(lastRead.startTime(), equalTo(timer.startTime()));
-            assertThat(lastRead.time(), equalTo(timer.time()));
-            assertThat(lastRead.stopTime(), equalTo(timer.stopTime()));
-        }
+        timer.stop();
+        assertTrue(timer.stopTime() >= timer.startTime());
+        assertTrue(timer.time() > 0);
+        // validate captured time
+        lastRead = streamer.serializeDeserialize();
+        assertEquals(timer.startTime(), lastRead.startTime());
+        assertEquals(timer.time(), lastRead.time());
+        assertEquals(timer.stopTime(), lastRead.stopTime());
 
         timer.reset();
-        assertThat(timer.startTime(), equalTo(0L));
-        assertThat(timer.time(), equalTo(0L));
-        assertThat(timer.stopTime(), equalTo(0L));
+        assertEquals(0, timer.startTime());
+        assertEquals(0, timer.time());
+        assertEquals(0, timer.stopTime());
+        // validate captured time
         lastRead = streamer.serializeDeserialize();
-        assertThat(lastRead.startTime(), equalTo(0L));
-        assertThat(lastRead.time(), equalTo(0L));
-        assertThat(lastRead.stopTime(), equalTo(0L));
-
+        assertEquals(0, lastRead.startTime());
+        assertEquals(0, lastRead.time());
+        assertEquals(0, lastRead.stopTime());
     }
 
     public void testIndex() throws Throwable {
-        FileDetail[] files = new FileDetail[randomIntBetween(1, 20)];
-        ArrayList<FileDetail> filesToRecover = new ArrayList<>();
+        FileMetadata[] files = new FileMetadata[randomIntBetween(1, 20)];
+        ArrayList<FileMetadata> filesToRecover = new ArrayList<>();
         long totalFileBytes = 0;
         long totalReusedBytes = 0;
         int totalReused = 0;
@@ -202,7 +209,7 @@ public void testIndex() throws Throwable {
             final int fileLength = randomIntBetween(1, 1000);
             final boolean reused = randomBoolean();
             totalFileBytes += fileLength;
-            files[i] = new FileDetail("f_" + i, fileLength, reused);
+            files[i] = new FileMetadata("f_" + i, fileLength, reused);
             if (reused) {
                 totalReused++;
                 totalReusedBytes += fileLength;
@@ -212,7 +219,7 @@ public void testIndex() throws Throwable {
         }
 
         Collections.shuffle(Arrays.asList(files), random());
-        final RecoveryState.Index index = new RecoveryState.Index();
+        final ReplicationLuceneIndex index = new ReplicationLuceneIndex();
         assertThat(index.bytesStillToRecover(), equalTo(-1L));
 
         if (randomBoolean()) {
@@ -239,11 +246,11 @@ public void testIndex() throws Throwable {
         // before we start we must report 0
         assertThat(index.recoveredFilesPercent(), equalTo((float) 0.0));
         assertThat(index.recoveredBytesPercent(), equalTo((float) 0.0));
-        assertThat(index.sourceThrottling().nanos(), equalTo(Index.UNKNOWN));
-        assertThat(index.targetThrottling().nanos(), equalTo(Index.UNKNOWN));
+        assertThat(index.sourceThrottling().nanos(), equalTo(ReplicationLuceneIndex.UNKNOWN));
+        assertThat(index.targetThrottling().nanos(), equalTo(ReplicationLuceneIndex.UNKNOWN));
 
         index.start();
-        for (FileDetail file : files) {
+        for (FileMetadata file : files) {
             index.addFileDetail(file.name(), file.length(), file.reused());
         }
 
@@ -271,24 +278,24 @@ public void testIndex() throws Throwable {
         }
         AtomicBoolean streamShouldStop = new AtomicBoolean();
 
-        Streamer<Index> backgroundReader = new Streamer<RecoveryState.Index>(streamShouldStop, index) {
+        Streamer<ReplicationLuceneIndex> backgroundReader = new Streamer<ReplicationLuceneIndex>(streamShouldStop, index) {
             @Override
-            Index createObj(StreamInput in) throws IOException {
-                return new Index(in);
+            ReplicationLuceneIndex createObj(StreamInput in) throws IOException {
+                return new ReplicationLuceneIndex(in);
             }
         };
 
         backgroundReader.start();
 
         long recoveredBytes = 0;
-        long sourceThrottling = Index.UNKNOWN;
-        long targetThrottling = Index.UNKNOWN;
+        long sourceThrottling = ReplicationLuceneIndex.UNKNOWN;
+        long targetThrottling = ReplicationLuceneIndex.UNKNOWN;
         while (bytesToRecover > 0) {
-            FileDetail file = randomFrom(filesToRecover);
+            FileMetadata file = randomFrom(filesToRecover);
             final long toRecover = Math.min(bytesToRecover, randomIntBetween(1, (int) (file.length() - file.recovered())));
             final long throttledOnSource = rarely() ? randomIntBetween(10, 200) : 0;
             index.addSourceThrottling(throttledOnSource);
-            if (sourceThrottling == Index.UNKNOWN) {
+            if (sourceThrottling == ReplicationLuceneIndex.UNKNOWN) {
                 sourceThrottling = throttledOnSource;
             } else {
                 sourceThrottling += throttledOnSource;
@@ -296,7 +303,7 @@ Index createObj(StreamInput in) throws IOException {
             index.addRecoveredBytesToFile(file.name(), toRecover);
             file.addRecoveredBytes(toRecover);
             final long throttledOnTarget = rarely() ? randomIntBetween(10, 200) : 0;
-            if (targetThrottling == Index.UNKNOWN) {
+            if (targetThrottling == ReplicationLuceneIndex.UNKNOWN) {
                 targetThrottling = throttledOnTarget;
             } else {
                 targetThrottling += throttledOnTarget;
@@ -318,7 +325,7 @@ Index createObj(StreamInput in) throws IOException {
         logger.info("testing serialized information");
         streamShouldStop.set(true);
         backgroundReader.join();
-        final Index lastRead = backgroundReader.lastRead();
+        final ReplicationLuceneIndex lastRead = backgroundReader.lastRead();
         assertThat(lastRead.fileDetails().toArray(), arrayContainingInAnyOrder(index.fileDetails().toArray()));
         assertThat(lastRead.startTime(), equalTo(index.startTime()));
         if (completeRecovery) {
@@ -536,12 +543,12 @@ VerifyIndex createObj(StreamInput in) throws IOException {
     }
 
     public void testConcurrentModificationIndexFileDetailsMap() throws InterruptedException {
-        final Index index = new Index();
+        final ReplicationLuceneIndex index = new ReplicationLuceneIndex();
         final AtomicBoolean stop = new AtomicBoolean(false);
-        Streamer<Index> readWriteIndex = new Streamer<Index>(stop, index) {
+        Streamer<ReplicationLuceneIndex> readWriteIndex = new Streamer<ReplicationLuceneIndex>(stop, index) {
             @Override
-            Index createObj(StreamInput in) throws IOException {
-                return new Index(in);
+            ReplicationLuceneIndex createObj(StreamInput in) throws IOException {
+                return new ReplicationLuceneIndex(in);
             }
         };
         Thread modifyThread = new Thread() {
@@ -561,14 +568,14 @@ public void run() {
     }
 
     public void testFileHashCodeAndEquals() {
-        FileDetail f = new FileDetail("foo", randomIntBetween(0, 100), randomBoolean());
-        FileDetail anotherFile = new FileDetail(f.name(), f.length(), f.reused());
+        FileMetadata f = new FileMetadata("foo", randomIntBetween(0, 100), randomBoolean());
+        FileMetadata anotherFile = new FileMetadata(f.name(), f.length(), f.reused());
         assertEquals(f, anotherFile);
         assertEquals(f.hashCode(), anotherFile.hashCode());
         int iters = randomIntBetween(10, 100);
         for (int i = 0; i < iters; i++) {
-            f = new FileDetail("foo", randomIntBetween(0, 100), randomBoolean());
-            anotherFile = new FileDetail(f.name(), randomIntBetween(0, 100), randomBoolean());
+            f = new FileMetadata("foo", randomIntBetween(0, 100), randomBoolean());
+            anotherFile = new FileMetadata(f.name(), randomIntBetween(0, 100), randomBoolean());
             if (f.equals(anotherFile)) {
                 assertEquals(f.hashCode(), anotherFile.hashCode());
             } else if (f.hashCode() != anotherFile.hashCode()) {
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RecoveryTests.java b/server/src/test/java/org/opensearch/indices/recovery/RecoveryTests.java
index 5e09e0f2253df..ad90255a3cc3f 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/RecoveryTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/RecoveryTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.indices.recovery;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexCommit;
 import org.apache.lucene.index.IndexWriter;
@@ -41,25 +42,26 @@
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.bulk.BulkShardRequest;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
+import org.opensearch.index.MergePolicyProvider;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.DocIdSeqNoAndSource;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineFactory;
 import org.opensearch.index.engine.InternalEngineFactory;
 import org.opensearch.index.engine.InternalEngineTests;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
 import org.opensearch.index.mapper.SourceToParse;
 import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
 import org.opensearch.index.replication.RecoveryDuringReplicationTests;
@@ -68,11 +70,16 @@
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.SnapshotMatchers;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationType;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicReference;
@@ -100,6 +107,17 @@ public void testTranslogHistoryTransferred() throws Exception {
         }
     }
 
+    public void testWithSegmentReplication_ReplicaUsesPrimaryTranslogUUID() throws Exception {
+        Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        try (ReplicationGroup shards = createGroup(2, settings, new NRTReplicationEngineFactory())) {
+            shards.startAll();
+            final String expectedUUID = getTranslog(shards.getPrimary()).getTranslogUUID();
+            assertTrue(
+                shards.getReplicas().stream().allMatch(indexShard -> getTranslog(indexShard).getTranslogUUID().equals(expectedUUID))
+            );
+        }
+    }
+
     public void testRetentionPolicyChangeDuringRecovery() throws Exception {
         try (ReplicationGroup shards = createGroup(0)) {
             shards.startPrimary();
@@ -150,7 +168,7 @@ public void testRecoveryWithOutOfOrderDeleteWithSoftDeletes() throws Exception {
             .put(IndexSettings.INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING.getKey(), 10)
             // If soft-deletes is enabled, delete#1 will be reclaimed because its segment (segment_1) is fully deleted
             // index#0 will be retained if merge is disabled; otherwise it will be reclaimed because gcp=3 and retained_ops=0
-            .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+            .put(MergePolicyProvider.INDEX_MERGE_ENABLED, false)
             .build();
         try (ReplicationGroup shards = createGroup(1, settings)) {
             shards.startAll();
@@ -165,43 +183,47 @@ public void testRecoveryWithOutOfOrderDeleteWithSoftDeletes() throws Exception {
             orgReplica.flush(new FlushRequest().force(true)); // isolate delete#1 in its own translog generation and lucene segment
             // index #0
             orgReplica.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 0,
                 primaryTerm,
                 1,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(indexName, "id", new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(indexName, "id", new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             // index #3
             orgReplica.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 3,
                 primaryTerm,
                 1,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(indexName, "id-3", new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(indexName, "id-3", new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             // Flushing a new commit with local checkpoint=1 allows to delete the translog gen #1.
             orgReplica.flush(new FlushRequest().force(true).waitIfOngoing(true));
             // index #2
             orgReplica.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 2,
                 primaryTerm,
                 1,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(indexName, "id-2", new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(indexName, "id-2", new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
             orgReplica.sync(); // advance local checkpoint
             orgReplica.updateGlobalCheckpointOnReplica(3L, "test");
             // index #5 -> force NoOp #4.
             orgReplica.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 5,
                 primaryTerm,
                 1,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false,
-                new SourceToParse(indexName, "id-5", new BytesArray("{}"), XContentType.JSON)
+                new SourceToParse(indexName, "id-5", new BytesArray("{}"), MediaTypeRegistry.JSON)
             );
 
             if (randomBoolean()) {
@@ -246,7 +268,7 @@ public void testDifferentHistoryUUIDDisablesOPsRecovery() throws Exception {
             final String historyUUID = replica.getHistoryUUID();
             Translog.TranslogGeneration translogGeneration = getTranslog(replica).getGeneration();
             shards.removeReplica(replica);
-            replica.close("test", false);
+            replica.close("test", false, false);
             IndexWriterConfig iwc = new IndexWriterConfig(null).setCommitOnClose(false)
                 // we don't want merges to happen here - we call maybe merge on the engine
                 // later once we stared it up otherwise we would need to wait for it here
@@ -310,7 +332,7 @@ public void testPeerRecoverySendSafeCommitInFileBased() throws Exception {
             Engine.IndexResult result = primaryShard.applyIndexOperationOnPrimary(
                 Versions.MATCH_ANY,
                 VersionType.INTERNAL,
-                new SourceToParse(primaryShard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), XContentType.JSON),
+                new SourceToParse(primaryShard.shardId().getIndexName(), Integer.toString(i), new BytesArray("{}"), MediaTypeRegistry.JSON),
                 SequenceNumbers.UNASSIGNED_SEQ_NO,
                 0,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
@@ -370,7 +392,7 @@ public void testSequenceBasedRecoveryKeepsTranslog() throws Exception {
             if (randomBoolean()) {
                 shards.flush();
             }
-            replica.close("test", randomBoolean());
+            replica.close("test", randomBoolean(), false);
             replica.store().close();
             final IndexShard newReplica = shards.addReplicaWithExistingPath(replica.shardPath(), replica.routingEntry().currentNodeId());
             shards.recoverReplica(newReplica);
@@ -448,20 +470,17 @@ public long addDocument(Iterable<? extends IndexableField> doc) throws IOExcepti
             IndexShard replica = group.addReplica();
             expectThrows(
                 Exception.class,
-                () -> group.recoverReplica(
-                    replica,
-                    (shard, sourceNode) -> new RecoveryTarget(shard, sourceNode, new PeerRecoveryTargetService.RecoveryListener() {
-                        @Override
-                        public void onRecoveryDone(RecoveryState state) {
-                            throw new AssertionError("recovery must fail");
-                        }
+                () -> group.recoverReplica(replica, (shard, sourceNode) -> new RecoveryTarget(shard, sourceNode, new ReplicationListener() {
+                    @Override
+                    public void onDone(ReplicationState state) {
+                        throw new AssertionError("recovery must fail");
+                    }
 
-                        @Override
-                        public void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure) {
-                            assertThat(ExceptionsHelper.unwrap(e, IOException.class).getMessage(), equalTo("simulated"));
-                        }
-                    })
-                )
+                    @Override
+                    public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                        assertThat(ExceptionsHelper.unwrap(e, IOException.class).getMessage(), equalTo("simulated"));
+                    }
+                }))
             );
             expectThrows(AlreadyClosedException.class, () -> replica.refresh("test"));
             group.removeReplica(replica);
@@ -480,7 +499,7 @@ public void testRecoveryTrimsLocalTranslog() throws Exception {
             }
             int inflightDocs = scaledRandomIntBetween(1, 100);
             for (int i = 0; i < inflightDocs; i++) {
-                final IndexRequest indexRequest = new IndexRequest(index.getName()).id("extra_" + i).source("{}", XContentType.JSON);
+                final IndexRequest indexRequest = new IndexRequest(index.getName()).id("extra_" + i).source("{}", MediaTypeRegistry.JSON);
                 final BulkShardRequest bulkShardRequest = indexOnPrimary(indexRequest, oldPrimary);
                 for (IndexShard replica : randomSubsetOf(shards.getReplicas())) {
                     indexOnReplica(bulkShardRequest, shards, replica);
@@ -491,7 +510,7 @@ public void testRecoveryTrimsLocalTranslog() throws Exception {
             }
             shards.syncGlobalCheckpoint();
             shards.promoteReplicaToPrimary(randomFrom(shards.getReplicas())).get();
-            oldPrimary.close("demoted", false);
+            oldPrimary.close("demoted", false, false);
             oldPrimary.store().close();
             oldPrimary = shards.addReplicaWithExistingPath(oldPrimary.shardPath(), oldPrimary.routingEntry().currentNodeId());
             shards.recoverReplica(oldPrimary);
diff --git a/server/src/test/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandlerTests.java b/server/src/test/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandlerTests.java
new file mode 100644
index 0000000000000..131514eb019b3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/recovery/RemoteStorePeerRecoverySourceHandlerTests.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.seqno.ReplicationTracker;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.replication.common.ReplicationType;
+
+import java.nio.file.Path;
+
+public class RemoteStorePeerRecoverySourceHandlerTests extends OpenSearchIndexLevelReplicationTestCase {
+
+    private static final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+        .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "translog-repo")
+        .put(IndexSettings.INDEX_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING.getKey(), "100ms")
+        .build();
+
+    public void testReplicaShardRecoveryUptoLastFlushedCommit() throws Exception {
+        final Path remoteDir = createTempDir();
+        final String indexMapping = "{ \"" + MapperService.SINGLE_MAPPING_NAME + "\": {} }";
+        try (ReplicationGroup shards = createGroup(0, settings, indexMapping, new NRTReplicationEngineFactory(), remoteDir)) {
+
+            // Step1 - Start primary, index docs and flush
+            shards.startPrimary();
+            final IndexShard primary = shards.getPrimary();
+            int numDocs = shards.indexDocs(randomIntBetween(10, 20));
+            logger.info("--> Index numDocs {} and flush", numDocs);
+            shards.flush();
+
+            // Step 2 - Start replica for recovery to happen, check both has same number of docs
+            final IndexShard replica1 = shards.addReplica(remoteDir);
+            logger.info("--> Added and started replica {}", replica1.routingEntry());
+            shards.startAll();
+            assertEquals(getDocIdAndSeqNos(primary), getDocIdAndSeqNos(replica1));
+
+            // Step 3 - Index more docs, run segment replication, check both have same number of docs
+            int moreDocs = shards.indexDocs(randomIntBetween(10, 20));
+            primary.refresh("test");
+            logger.info("--> Index more docs {} and replicate segments", moreDocs);
+            replicateSegments(primary, shards.getReplicas());
+            assertEquals(getDocIdAndSeqNos(primary), getDocIdAndSeqNos(replica1));
+
+            // Step 4 - Check both shard has expected number of doc count
+            assertDocCount(primary, numDocs + moreDocs);
+            assertDocCount(replica1, numDocs + moreDocs);
+
+            // Step 5 - Check retention lease does not exist for the replica shard
+            assertEquals(1, primary.getRetentionLeases().leases().size());
+            assertFalse(primary.getRetentionLeases().contains(ReplicationTracker.getPeerRecoveryRetentionLeaseId(replica1.routingEntry())));
+
+            // Step 6 - Start new replica, recovery happens, and check that new replica has all docs
+            final IndexShard replica2 = shards.addReplica(remoteDir);
+            logger.info("--> Added and started replica {}", replica2.routingEntry());
+            shards.startAll();
+            shards.assertAllEqual(numDocs + moreDocs);
+
+            // Step 7 - Check retention lease does not exist for the replica shard
+            assertEquals(1, primary.getRetentionLeases().leases().size());
+            assertFalse(primary.getRetentionLeases().contains(ReplicationTracker.getPeerRecoveryRetentionLeaseId(replica2.routingEntry())));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/recovery/ReplicationRequestTrackerTests.java b/server/src/test/java/org/opensearch/indices/recovery/ReplicationRequestTrackerTests.java
new file mode 100644
index 0000000000000..fb221728f03d7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/recovery/ReplicationRequestTrackerTests.java
@@ -0,0 +1,126 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.indices.replication.common.ReplicationRequestTracker;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+
+import java.util.Collection;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
+
+public class ReplicationRequestTrackerTests extends OpenSearchTestCase {
+
+    private TestThreadPool threadPool;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool(getTestName());
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        terminate(threadPool);
+        super.tearDown();
+    }
+
+    public void testIdempotencyIsEnforced() {
+        Set<Long> seqNosReturned = ConcurrentCollections.newConcurrentSet();
+        ConcurrentMap<Long, Set<PlainActionFuture<Void>>> seqToResult = ConcurrentCollections.newConcurrentMap();
+
+        ReplicationRequestTracker requestTracker = new ReplicationRequestTracker();
+
+        int numberOfRequests = randomIntBetween(100, 200);
+        for (int j = 0; j < numberOfRequests; ++j) {
+            final long seqNo = j;
+            int iterations = randomIntBetween(2, 5);
+            for (int i = 0; i < iterations; ++i) {
+                PlainActionFuture<Void> future = PlainActionFuture.newFuture();
+                Set<PlainActionFuture<Void>> set = seqToResult.computeIfAbsent(seqNo, (k) -> ConcurrentCollections.newConcurrentSet());
+                set.add(future);
+                threadPool.generic().execute(() -> {
+                    ActionListener<Void> listener = requestTracker.markReceivedAndCreateListener(seqNo, future);
+                    if (listener != null) {
+                        boolean added = seqNosReturned.add(seqNo);
+                        // Ensure that we only return 1 future per sequence number
+                        assertTrue(added);
+                        if (rarely()) {
+                            listener.onFailure(new OpenSearchException(randomAlphaOfLength(10)));
+                        } else {
+                            listener.onResponse(null);
+                        }
+                    }
+                });
+            }
+        }
+
+        seqToResult.values().stream().flatMap(Collection::stream).forEach(f -> {
+            try {
+                f.actionGet();
+            } catch (Exception e) {
+                // Ignore for now. We will assert later.
+            }
+        });
+
+        for (Set<PlainActionFuture<Void>> value : seqToResult.values()) {
+            Optional<PlainActionFuture<Void>> first = value.stream().findFirst();
+            assertTrue(first.isPresent());
+            Exception expectedException = null;
+            try {
+                first.get().actionGet();
+            } catch (Exception e) {
+                expectedException = e;
+            }
+            for (PlainActionFuture<Void> future : value) {
+                assertTrue(future.isDone());
+                if (expectedException == null) {
+                    future.actionGet();
+                } else {
+                    try {
+                        future.actionGet();
+                        fail("expected exception");
+                    } catch (Exception e) {
+                        assertEquals(expectedException.getMessage(), e.getMessage());
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/recovery/StartRecoveryRequestTests.java b/server/src/test/java/org/opensearch/indices/recovery/StartRecoveryRequestTests.java
index 9ad8403cea14d..b76f830fe8431 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/StartRecoveryRequestTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/StartRecoveryRequestTests.java
@@ -35,11 +35,11 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/indices/replication/OngoingSegmentReplicationsTests.java b/server/src/test/java/org/opensearch/indices/replication/OngoingSegmentReplicationsTests.java
new file mode 100644
index 0000000000000..44e2653cf01da
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/OngoingSegmentReplicationsTests.java
@@ -0,0 +1,440 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+public class OngoingSegmentReplicationsTests extends IndexShardTestCase {
+
+    private final IndicesService mockIndicesService = mock(IndicesService.class);
+    private ReplicationCheckpoint testCheckpoint;
+    private DiscoveryNode primaryDiscoveryNode;
+    private DiscoveryNode replicaDiscoveryNode;
+    private IndexShard primary;
+    private IndexShard replica;
+
+    private GetSegmentFilesRequest getSegmentFilesRequest;
+
+    final Settings settings = Settings.builder()
+        .put("node.name", SegmentReplicationTargetServiceTests.class.getSimpleName())
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .build();
+    final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+    final RecoverySettings recoverySettings = new RecoverySettings(settings, clusterSettings);
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        primary = newStartedShard(true, settings);
+        replica = newShard(false, settings, new NRTReplicationEngineFactory());
+        recoverReplica(replica, primary, true);
+        replicaDiscoveryNode = replica.recoveryState().getTargetNode();
+        primaryDiscoveryNode = replica.recoveryState().getSourceNode();
+
+        ShardId testShardId = primary.shardId();
+
+        CodecService codecService = new CodecService(null, getEngine(primary).config().getIndexSettings(), null);
+        String defaultCodecName = codecService.codec(CodecService.DEFAULT_CODEC).getName();
+
+        // This mirrors the creation of the ReplicationCheckpoint inside CopyState
+        testCheckpoint = new ReplicationCheckpoint(testShardId, primary.getOperationPrimaryTerm(), 0L, 0L, defaultCodecName);
+        IndexService mockIndexService = mock(IndexService.class);
+        when(mockIndicesService.indexServiceSafe(testShardId.getIndex())).thenReturn(mockIndexService);
+        when(mockIndexService.getShard(testShardId.id())).thenReturn(primary);
+
+        TransportService transportService = mock(TransportService.class);
+        when(transportService.getThreadPool()).thenReturn(threadPool);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        closeShards(primary, replica);
+        super.tearDown();
+    }
+
+    public void testPrepareAndSendSegments() throws IOException {
+        indexDoc(primary, "1", "{\"foo\" : \"baz\"}", MediaTypeRegistry.JSON, "foobar");
+        primary.refresh("Test");
+        OngoingSegmentReplications replications = spy(new OngoingSegmentReplications(mockIndicesService, recoverySettings));
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        final FileChunkWriter segmentSegmentFileChunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> {
+            listener.onResponse(null);
+        };
+        final CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertTrue(replications.isInCopyStateMap(request.getCheckpoint()));
+        assertEquals(1, replications.size());
+        assertEquals(1, copyState.refCount());
+
+        getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            new ArrayList<>(copyState.getMetadataMap().values()),
+            testCheckpoint
+        );
+
+        replications.startSegmentCopy(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                assertEquals(copyState.getMetadataMap().size(), getSegmentFilesResponse.files.size());
+                assertEquals(0, copyState.refCount());
+                assertFalse(replications.isInCopyStateMap(request.getCheckpoint()));
+                assertEquals(0, replications.size());
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Unexpected failure", e);
+                Assert.fail("Unexpected failure from startSegmentCopy listener: " + e);
+            }
+        });
+    }
+
+    public void testCancelReplication() throws IOException {
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            primaryDiscoveryNode,
+            testCheckpoint
+        );
+        final FileChunkWriter segmentSegmentFileChunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> {
+            // this shouldn't be called in this test.
+            Assert.fail();
+        };
+        final CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertEquals(1, replications.size());
+        assertEquals(1, replications.cachedCopyStateSize());
+
+        replications.cancelReplication(primaryDiscoveryNode);
+        assertEquals(0, copyState.refCount());
+        assertEquals(0, replications.size());
+        assertEquals(0, replications.cachedCopyStateSize());
+    }
+
+    public void testCancelReplication_AfterSendFilesStarts() throws IOException, InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        // add a doc and refresh so primary has more than one segment.
+        indexDoc(primary, "1", "{\"foo\" : \"baz\"}", MediaTypeRegistry.JSON, "foobar");
+        primary.refresh("Test");
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            primaryDiscoveryNode,
+            testCheckpoint
+        );
+        final FileChunkWriter segmentSegmentFileChunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> {
+            // cancel the replication as soon as the writer starts sending files.
+            replications.cancel(replica.routingEntry().allocationId().getId(), "Test");
+        };
+        final CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertEquals(1, replications.size());
+        assertEquals(1, replications.cachedCopyStateSize());
+        getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            new ArrayList<>(copyState.getMetadataMap().values()),
+            testCheckpoint
+        );
+        replications.startSegmentCopy(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                Assert.fail("Expected onFailure to be invoked.");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(CancellableThreads.ExecutionCancelledException.class, e.getClass());
+                assertEquals(0, copyState.refCount());
+                assertEquals(0, replications.size());
+                assertEquals(0, replications.cachedCopyStateSize());
+                latch.countDown();
+            }
+        });
+        latch.await(2, TimeUnit.SECONDS);
+        assertEquals("listener should have resolved with failure", 0, latch.getCount());
+    }
+
+    public void testMultipleReplicasUseSameCheckpoint() throws IOException {
+        IndexShard secondReplica = newShard(primary.shardId(), false);
+        recoverReplica(secondReplica, primary, true);
+
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            primaryDiscoveryNode,
+            testCheckpoint
+        );
+        final FileChunkWriter segmentSegmentFileChunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> {
+            // this shouldn't be called in this test.
+            Assert.fail();
+        };
+
+        final CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertEquals(1, copyState.refCount());
+
+        final CheckpointInfoRequest secondRequest = new CheckpointInfoRequest(
+            1L,
+            secondReplica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        replications.prepareForReplication(secondRequest, segmentSegmentFileChunkWriter);
+
+        assertEquals(2, copyState.refCount());
+        assertEquals(2, replications.size());
+        assertEquals(1, replications.cachedCopyStateSize());
+
+        replications.cancelReplication(primaryDiscoveryNode);
+        replications.cancelReplication(replicaDiscoveryNode);
+        assertEquals(0, copyState.refCount());
+        assertEquals(0, replications.size());
+        assertEquals(0, replications.cachedCopyStateSize());
+        closeShards(secondReplica);
+    }
+
+    public void testStartCopyWithoutPrepareStep() {
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final ActionListener<GetSegmentFilesResponse> listener = spy(new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                assertTrue(getSegmentFilesResponse.files.isEmpty());
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                Assert.fail();
+            }
+        });
+
+        getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            Collections.emptyList(),
+            testCheckpoint
+        );
+
+        replications.startSegmentCopy(getSegmentFilesRequest, listener);
+        verify(listener, times(1)).onResponse(any());
+    }
+
+    public void testShardAlreadyReplicatingToNode() throws IOException {
+        OngoingSegmentReplications replications = spy(new OngoingSegmentReplications(mockIndicesService, recoverySettings));
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        final FileChunkWriter segmentSegmentFileChunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> {
+            listener.onResponse(null);
+        };
+        replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertEquals(1, copyState.refCount());
+    }
+
+    public void testStartReplicationWithNoFilesToFetch() throws IOException {
+        // create a replications object and request a checkpoint.
+        OngoingSegmentReplications replications = spy(new OngoingSegmentReplications(mockIndicesService, recoverySettings));
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        // mock the FileChunkWriter so we can assert its ever called.
+        final FileChunkWriter segmentSegmentFileChunkWriter = mock(FileChunkWriter.class);
+        // Prepare for replication step - and ensure copyState is added to cache.
+        final CopyState copyState = replications.prepareForReplication(request, segmentSegmentFileChunkWriter);
+        assertTrue(replications.isInCopyStateMap(request.getCheckpoint()));
+        assertEquals(1, replications.size());
+        assertEquals(1, copyState.refCount());
+
+        getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            Collections.emptyList(),
+            testCheckpoint
+        );
+
+        // invoke startSegmentCopy and assert our fileChunkWriter is never invoked.
+        replications.startSegmentCopy(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                assertEquals(Collections.emptyList(), getSegmentFilesResponse.files);
+                assertEquals(0, copyState.refCount());
+                assertFalse(replications.isInCopyStateMap(request.getCheckpoint()));
+                verifyNoInteractions(segmentSegmentFileChunkWriter);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Unexpected failure", e);
+                Assert.fail();
+            }
+        });
+    }
+
+    public void testCancelAllReplicationsForShard() throws IOException {
+        // This tests when primary has multiple ongoing replications.
+        IndexShard replica_2 = newShard(primary.shardId(), false);
+        recoverReplica(replica_2, primary, true);
+
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            primaryDiscoveryNode,
+            testCheckpoint
+        );
+
+        final CopyState copyState = replications.prepareForReplication(request, mock(FileChunkWriter.class));
+        assertEquals(1, copyState.refCount());
+
+        final CheckpointInfoRequest secondRequest = new CheckpointInfoRequest(
+            1L,
+            replica_2.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        replications.prepareForReplication(secondRequest, mock(FileChunkWriter.class));
+
+        assertEquals(2, copyState.refCount());
+        assertEquals(2, replications.size());
+        assertEquals(1, replications.cachedCopyStateSize());
+
+        // cancel the primary's ongoing replications.
+        replications.cancel(primary, "Test");
+        assertEquals(0, copyState.refCount());
+        assertEquals(0, replications.size());
+        assertEquals(0, replications.cachedCopyStateSize());
+        closeShards(replica_2);
+    }
+
+    public void testCancelForMissingIds() throws IOException {
+        // This tests when primary has multiple ongoing replications.
+        IndexShard replica_2 = newShard(primary.shardId(), false);
+        recoverReplica(replica_2, primary, true);
+
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final String replicaAllocationId = replica.routingEntry().allocationId().getId();
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(1L, replicaAllocationId, primaryDiscoveryNode, testCheckpoint);
+
+        final CopyState copyState = replications.prepareForReplication(request, mock(FileChunkWriter.class));
+        assertEquals(1, copyState.refCount());
+
+        final String replica_2AllocationId = replica_2.routingEntry().allocationId().getId();
+        final CheckpointInfoRequest secondRequest = new CheckpointInfoRequest(
+            1L,
+            replica_2AllocationId,
+            replicaDiscoveryNode,
+            testCheckpoint
+        );
+        replications.prepareForReplication(secondRequest, mock(FileChunkWriter.class));
+
+        assertEquals(2, copyState.refCount());
+        assertEquals(2, replications.size());
+        assertTrue(replications.getHandlers().containsKey(replicaAllocationId));
+        assertTrue(replications.getHandlers().containsKey(replica_2AllocationId));
+        assertEquals(1, replications.cachedCopyStateSize());
+
+        replications.clearOutOfSyncIds(primary.shardId(), Set.of(replica_2AllocationId));
+        assertEquals(1, copyState.refCount());
+        assertEquals(1, replications.size());
+        assertTrue(replications.getHandlers().containsKey(replica_2AllocationId));
+        assertEquals(1, replications.cachedCopyStateSize());
+
+        // cancel the primary's ongoing replications.
+        replications.clearOutOfSyncIds(primary.shardId(), Collections.emptySet());
+        assertEquals(0, copyState.refCount());
+        assertEquals(0, replications.size());
+        assertEquals(0, replications.cachedCopyStateSize());
+        closeShards(replica_2);
+    }
+
+    public void testPrepareForReplicationAlreadyReplicating() throws IOException {
+        OngoingSegmentReplications replications = new OngoingSegmentReplications(mockIndicesService, recoverySettings);
+        final String replicaAllocationId = replica.routingEntry().allocationId().getId();
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(1L, replicaAllocationId, primaryDiscoveryNode, testCheckpoint);
+
+        final CopyState copyState = replications.prepareForReplication(request, mock(FileChunkWriter.class));
+
+        final SegmentReplicationSourceHandler handler = replications.getHandlers().get(replicaAllocationId);
+        assertEquals(handler.getCopyState(), copyState);
+        assertEquals(1, copyState.refCount());
+
+        ReplicationCheckpoint secondCheckpoint = new ReplicationCheckpoint(
+            testCheckpoint.getShardId(),
+            testCheckpoint.getPrimaryTerm(),
+            testCheckpoint.getSegmentsGen(),
+            testCheckpoint.getSegmentInfosVersion() + 1,
+            testCheckpoint.getCodec()
+        );
+
+        final CheckpointInfoRequest secondRequest = new CheckpointInfoRequest(
+            1L,
+            replicaAllocationId,
+            primaryDiscoveryNode,
+            secondCheckpoint
+        );
+
+        final CopyState secondCopyState = replications.prepareForReplication(secondRequest, mock(FileChunkWriter.class));
+        final SegmentReplicationSourceHandler secondHandler = replications.getHandlers().get(replicaAllocationId);
+        assertEquals(secondHandler.getCopyState(), secondCopyState);
+        assertEquals("New copy state is incref'd", 1, secondCopyState.refCount());
+        assertEquals("Old copy state is cleaned up", 0, copyState.refCount());
+
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/PrimaryShardReplicationSourceTests.java b/server/src/test/java/org/opensearch/indices/replication/PrimaryShardReplicationSourceTests.java
new file mode 100644
index 0000000000000..bcacef83d190a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/PrimaryShardReplicationSourceTests.java
@@ -0,0 +1,209 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.util.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.ClusterServiceUtils;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.mockito.Mockito.mock;
+
+public class PrimaryShardReplicationSourceTests extends IndexShardTestCase {
+
+    private static final long PRIMARY_TERM = 1L;
+    private static final long SEGMENTS_GEN = 2L;
+    private static final long SEQ_NO = 3L;
+    private static final long VERSION = 4L;
+    private static final long REPLICATION_ID = 123L;
+
+    private CapturingTransport transport;
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private PrimaryShardReplicationSource replicationSource;
+    private IndexShard indexShard;
+    private DiscoveryNode sourceNode;
+
+    private RecoverySettings recoverySettings;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        final Settings settings = Settings.builder().put("node.name", SegmentReplicationTargetServiceTests.class.getSimpleName()).build();
+        final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        final RecoverySettings recoverySettings = new RecoverySettings(settings, clusterSettings);
+        transport = new CapturingTransport();
+        sourceNode = newDiscoveryNode("sourceNode");
+        final DiscoveryNode localNode = newDiscoveryNode("localNode");
+        clusterService = ClusterServiceUtils.createClusterService(threadPool, localNode);
+        transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        indexShard = newStartedShard(true);
+
+        this.recoverySettings = recoverySettings;
+        replicationSource = new PrimaryShardReplicationSource(
+            localNode,
+            indexShard.routingEntry().allocationId().toString(),
+            transportService,
+            recoverySettings,
+            sourceNode
+        );
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        IOUtils.close(transportService, clusterService, transport);
+        closeShards(indexShard);
+        super.tearDown();
+    }
+
+    public void testGetCheckpointMetadata() {
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(
+            indexShard.shardId(),
+            PRIMARY_TERM,
+            SEGMENTS_GEN,
+            VERSION,
+            Codec.getDefault().getName()
+        );
+        replicationSource.getCheckpointMetadata(REPLICATION_ID, checkpoint, mock(ActionListener.class));
+        CapturingTransport.CapturedRequest[] requestList = transport.getCapturedRequestsAndClear();
+        assertEquals(1, requestList.length);
+        CapturingTransport.CapturedRequest capturedRequest = requestList[0];
+        assertEquals(SegmentReplicationSourceService.Actions.GET_CHECKPOINT_INFO, capturedRequest.action);
+        assertEquals(sourceNode, capturedRequest.node);
+        assertTrue(capturedRequest.request instanceof CheckpointInfoRequest);
+    }
+
+    public void testGetSegmentFiles() {
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(
+            indexShard.shardId(),
+            PRIMARY_TERM,
+            SEGMENTS_GEN,
+            VERSION,
+            Codec.getDefault().getName()
+        );
+        StoreFileMetadata testMetadata = new StoreFileMetadata("testFile", 1L, "checksum", Version.LATEST);
+        replicationSource.getSegmentFiles(
+            REPLICATION_ID,
+            checkpoint,
+            Arrays.asList(testMetadata),
+            mock(IndexShard.class),
+            mock(ActionListener.class)
+        );
+        CapturingTransport.CapturedRequest[] requestList = transport.getCapturedRequestsAndClear();
+        assertEquals(1, requestList.length);
+        CapturingTransport.CapturedRequest capturedRequest = requestList[0];
+        assertEquals(SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES, capturedRequest.action);
+        assertEquals(sourceNode, capturedRequest.node);
+        assertTrue(capturedRequest.request instanceof GetSegmentFilesRequest);
+    }
+
+    /**
+     * This test verifies the transport request timeout value for fetching the segment files.
+     */
+    public void testTransportTimeoutForGetSegmentFilesAction() {
+        long fileSize = (long) (Math.pow(10, 9));
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(
+            indexShard.shardId(),
+            PRIMARY_TERM,
+            SEGMENTS_GEN,
+            VERSION,
+            Codec.getDefault().getName()
+        );
+        StoreFileMetadata testMetadata = new StoreFileMetadata("testFile", fileSize, "checksum", Version.LATEST);
+        replicationSource.getSegmentFiles(
+            REPLICATION_ID,
+            checkpoint,
+            Arrays.asList(testMetadata),
+            mock(IndexShard.class),
+            mock(ActionListener.class)
+        );
+        CapturingTransport.CapturedRequest[] requestList = transport.getCapturedRequestsAndClear();
+        assertEquals(1, requestList.length);
+        CapturingTransport.CapturedRequest capturedRequest = requestList[0];
+        assertEquals(SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES, capturedRequest.action);
+        assertEquals(sourceNode, capturedRequest.node);
+        assertEquals(recoverySettings.internalActionLongTimeout(), capturedRequest.options.timeout());
+    }
+
+    public void testGetSegmentFiles_CancelWhileRequestOpen() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(
+            indexShard.shardId(),
+            PRIMARY_TERM,
+            SEGMENTS_GEN,
+            VERSION,
+            Codec.getDefault().getName()
+        );
+        StoreFileMetadata testMetadata = new StoreFileMetadata("testFile", 1L, "checksum", Version.LATEST);
+        replicationSource.getSegmentFiles(
+            REPLICATION_ID,
+            checkpoint,
+            Arrays.asList(testMetadata),
+            mock(IndexShard.class),
+            new ActionListener<>() {
+                @Override
+                public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                    Assert.fail("onFailure response expected.");
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    assertEquals(e.getClass(), CancellableThreads.ExecutionCancelledException.class);
+                    latch.countDown();
+                }
+            }
+        );
+        replicationSource.cancel();
+        latch.await(2, TimeUnit.SECONDS);
+        assertEquals("listener should have resolved in a failure", 0, latch.getCount());
+    }
+
+    private DiscoveryNode newDiscoveryNode(String nodeName) {
+        return new DiscoveryNode(
+            nodeName,
+            randomAlphaOfLength(10),
+            buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),
+            org.opensearch.Version.CURRENT
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/RemoteStoreReplicationSourceTests.java b/server/src/test/java/org/opensearch/indices/replication/RemoteStoreReplicationSourceTests.java
new file mode 100644
index 0000000000000..9204f48ba5bdd
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/RemoteStoreReplicationSourceTests.java
@@ -0,0 +1,159 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.store.FilterDirectory;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardState;
+import org.opensearch.index.shard.RemoteStoreRefreshListenerTests;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationType;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.stream.Collectors;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class RemoteStoreReplicationSourceTests extends OpenSearchIndexLevelReplicationTestCase {
+    private static final long REPLICATION_ID = 123L;
+    private RemoteStoreReplicationSource replicationSource;
+    private IndexShard primaryShard;
+
+    private IndexShard replicaShard;
+    private final Settings settings = Settings.builder()
+        .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+        .put(IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, "my-repo")
+        .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "my-repo")
+        .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+        .build();
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        primaryShard = newStartedShard(true, settings, new InternalEngineFactory());
+        indexDoc(primaryShard, "_doc", "1");
+        indexDoc(primaryShard, "_doc", "2");
+        primaryShard.refresh("test");
+        replicaShard = newStartedShard(false, settings, new NRTReplicationEngineFactory());
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        closeShards(primaryShard, replicaShard);
+        super.tearDown();
+    }
+
+    public void testGetCheckpointMetadata() throws ExecutionException, InterruptedException {
+        final ReplicationCheckpoint checkpoint = primaryShard.getLatestReplicationCheckpoint();
+        final PlainActionFuture<CheckpointInfoResponse> res = PlainActionFuture.newFuture();
+        replicationSource = new RemoteStoreReplicationSource(primaryShard);
+        replicationSource.getCheckpointMetadata(REPLICATION_ID, checkpoint, res);
+        CheckpointInfoResponse response = res.get();
+        assert (response.getCheckpoint().equals(checkpoint));
+        assert (response.getMetadataMap().isEmpty() == false);
+    }
+
+    public void testGetCheckpointMetadataFailure() {
+        IndexShard mockShard = mock(IndexShard.class);
+        final ReplicationCheckpoint checkpoint = primaryShard.getLatestReplicationCheckpoint();
+        when(mockShard.getSegmentInfosSnapshot()).thenThrow(new RuntimeException("test"));
+        assertThrows(RuntimeException.class, () -> {
+            replicationSource = new RemoteStoreReplicationSource(mockShard);
+            final PlainActionFuture<CheckpointInfoResponse> res = PlainActionFuture.newFuture();
+            replicationSource.getCheckpointMetadata(REPLICATION_ID, checkpoint, res);
+            res.get();
+        });
+    }
+
+    public void testGetSegmentFiles() throws ExecutionException, InterruptedException, IOException {
+        final ReplicationCheckpoint checkpoint = primaryShard.getLatestReplicationCheckpoint();
+        List<StoreFileMetadata> filesToFetch = primaryShard.getSegmentMetadataMap().values().stream().collect(Collectors.toList());
+        final PlainActionFuture<GetSegmentFilesResponse> res = PlainActionFuture.newFuture();
+        replicationSource = new RemoteStoreReplicationSource(primaryShard);
+        replicationSource.getSegmentFiles(REPLICATION_ID, checkpoint, filesToFetch, replicaShard, res);
+        GetSegmentFilesResponse response = res.get();
+        assertEquals(response.files.size(), filesToFetch.size());
+        assertTrue(response.files.containsAll(filesToFetch));
+        closeShards(replicaShard);
+    }
+
+    public void testGetSegmentFilesAlreadyExists() throws IOException, InterruptedException {
+        final ReplicationCheckpoint checkpoint = primaryShard.getLatestReplicationCheckpoint();
+        List<StoreFileMetadata> filesToFetch = primaryShard.getSegmentMetadataMap().values().stream().collect(Collectors.toList());
+        CountDownLatch latch = new CountDownLatch(1);
+        try {
+            final PlainActionFuture<GetSegmentFilesResponse> res = PlainActionFuture.newFuture();
+            replicationSource = new RemoteStoreReplicationSource(primaryShard);
+            replicationSource.getSegmentFiles(REPLICATION_ID, checkpoint, filesToFetch, primaryShard, res);
+            res.get();
+        } catch (AssertionError | ExecutionException ex) {
+            latch.countDown();
+            assertTrue(ex instanceof AssertionError);
+            assertTrue(ex.getMessage().startsWith("Local store already contains the file"));
+        }
+        latch.await();
+    }
+
+    public void testGetSegmentFilesReturnEmptyResponse() throws ExecutionException, InterruptedException {
+        final ReplicationCheckpoint checkpoint = primaryShard.getLatestReplicationCheckpoint();
+        final PlainActionFuture<GetSegmentFilesResponse> res = PlainActionFuture.newFuture();
+        replicationSource = new RemoteStoreReplicationSource(primaryShard);
+        replicationSource.getSegmentFiles(REPLICATION_ID, checkpoint, Collections.emptyList(), primaryShard, res);
+        GetSegmentFilesResponse response = res.get();
+        assert (response.files.isEmpty());
+    }
+
+    public void testGetCheckpointMetadataEmpty() throws ExecutionException, InterruptedException, IOException {
+        IndexShard mockShard = mock(IndexShard.class);
+        // Build mockShard to return replicaShard directory so that empty metadata file is returned.
+        buildIndexShardBehavior(mockShard, replicaShard);
+        replicationSource = new RemoteStoreReplicationSource(mockShard);
+
+        // Mock replica shard state to RECOVERING so that getCheckpointInfo return empty map
+        final ReplicationCheckpoint checkpoint = replicaShard.getLatestReplicationCheckpoint();
+        final PlainActionFuture<CheckpointInfoResponse> res = PlainActionFuture.newFuture();
+        when(mockShard.state()).thenReturn(IndexShardState.RECOVERING);
+        replicationSource = new RemoteStoreReplicationSource(mockShard);
+        // Recovering shard should just do a noop and return empty metadata map.
+        replicationSource.getCheckpointMetadata(REPLICATION_ID, checkpoint, res);
+        CheckpointInfoResponse response = res.get();
+        assert (response.getCheckpoint().equals(checkpoint));
+        assert (response.getMetadataMap().isEmpty());
+
+        // Started shard should fail with assertion error.
+        when(mockShard.state()).thenReturn(IndexShardState.STARTED);
+        expectThrows(AssertionError.class, () -> {
+            final PlainActionFuture<CheckpointInfoResponse> res2 = PlainActionFuture.newFuture();
+            replicationSource.getCheckpointMetadata(REPLICATION_ID, checkpoint, res2);
+        });
+    }
+
+    private void buildIndexShardBehavior(IndexShard mockShard, IndexShard indexShard) {
+        when(mockShard.getSegmentInfosSnapshot()).thenReturn(indexShard.getSegmentInfosSnapshot());
+        Store remoteStore = mock(Store.class);
+        when(mockShard.remoteStore()).thenReturn(remoteStore);
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory = (RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) indexShard.remoteStore().directory()).getDelegate()).getDelegate();
+        FilterDirectory remoteStoreFilterDirectory = new RemoteStoreRefreshListenerTests.TestFilterDirectory(new RemoteStoreRefreshListenerTests.TestFilterDirectory(remoteSegmentStoreDirectory));
+        when(remoteStore.directory()).thenReturn(remoteStoreFilterDirectory);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/SegmentFileTransferHandlerTests.java b/server/src/test/java/org/opensearch/indices/replication/SegmentFileTransferHandlerTests.java
new file mode 100644
index 0000000000000..f70d94bdbab81
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/SegmentFileTransferHandlerTests.java
@@ -0,0 +1,258 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.index.CorruptIndexException;
+import org.apache.lucene.index.IndexFileNames;
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.recovery.MultiChunkTransfer;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.function.IntSupplier;
+
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+
+public class SegmentFileTransferHandlerTests extends IndexShardTestCase {
+
+    private IndexShard shard;
+    private StoreFileMetadata[] filesToSend;
+    private final DiscoveryNode targetNode = new DiscoveryNode(
+        "foo",
+        buildNewFakeTransportAddress(),
+        emptyMap(),
+        emptySet(),
+        Version.CURRENT
+    );
+
+    final int fileChunkSizeInBytes = 5000;
+    final int maxConcurrentFileChunks = 1;
+    private CancellableThreads cancellableThreads;
+    final IntSupplier translogOps = () -> 0;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        cancellableThreads = new CancellableThreads();
+        shard = spy(newStartedShard(true));
+        filesToSend = getFilestoSend(shard);
+        // we should only have a Segments_N file at this point.
+        assertEquals(1, filesToSend.length);
+    }
+
+    private StoreFileMetadata[] getFilestoSend(IndexShard shard) throws IOException {
+        final Store.MetadataSnapshot metadata = shard.store().getMetadata();
+        return metadata.asMap().values().toArray(StoreFileMetadata[]::new);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        closeShards(shard);
+        super.tearDown();
+    }
+
+    public void testSendFiles_invokesChunkWriter() throws IOException, InterruptedException {
+        // use counDownLatch and countDown when our chunkWriter is invoked.
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        final FileChunkWriter chunkWriter = spy(new FileChunkWriter() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata fileMetadata,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                assertTrue(filesToSend[0].isSame(fileMetadata));
+                assertTrue(lastChunk);
+                countDownLatch.countDown();
+            }
+        });
+
+        SegmentFileTransferHandler handler = new SegmentFileTransferHandler(
+            shard,
+            targetNode,
+            chunkWriter,
+            logger,
+            shard.getThreadPool(),
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
+        final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = handler.createTransfer(
+            shard.store(),
+            filesToSend,
+            translogOps,
+            mock(ActionListener.class)
+        );
+
+        // start the transfer
+        transfer.start();
+        countDownLatch.await(5, TimeUnit.SECONDS);
+        verify(chunkWriter, times(1)).writeFileChunk(any(), anyLong(), any(), anyBoolean(), anyInt(), any());
+        IOUtils.close(transfer);
+    }
+
+    public void testSendFiles_cancelThreads_beforeStart() throws IOException, InterruptedException {
+        final FileChunkWriter chunkWriter = spy(new FileChunkWriter() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata fileMetadata,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                Assert.fail();
+            }
+        });
+        SegmentFileTransferHandler handler = new SegmentFileTransferHandler(
+            shard,
+            targetNode,
+            chunkWriter,
+            logger,
+            shard.getThreadPool(),
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
+
+        final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = handler.createTransfer(
+            shard.store(),
+            filesToSend,
+            translogOps,
+            mock(ActionListener.class)
+        );
+
+        // start the transfer
+        cancellableThreads.cancel("test");
+        transfer.start();
+        verifyNoInteractions(chunkWriter);
+        IOUtils.close(transfer);
+    }
+
+    public void testSendFiles_cancelThreads_afterStart() throws IOException, InterruptedException {
+        // index a doc a flush so we have more than 1 file to send.
+        indexDoc(shard, "_doc", "test");
+        flushShard(shard, true);
+        filesToSend = getFilestoSend(shard);
+
+        // we should have 4 files to send now -
+        // [_0.cfe, _0.si, _0.cfs, segments_3]
+        assertEquals(4, filesToSend.length);
+
+        final CountDownLatch countDownLatch = new CountDownLatch(1);
+        FileChunkWriter chunkWriter = spy(new FileChunkWriter() {
+            @Override
+            public void writeFileChunk(
+                StoreFileMetadata fileMetadata,
+                long position,
+                BytesReference content,
+                boolean lastChunk,
+                int totalTranslogOps,
+                ActionListener<Void> listener
+            ) {
+                // cancel the threads at this point, we'll ensure this is not invoked more than once.
+                cancellableThreads.cancel("test");
+                listener.onResponse(null);
+            }
+        });
+        SegmentFileTransferHandler handler = new SegmentFileTransferHandler(
+            shard,
+            targetNode,
+            chunkWriter,
+            logger,
+            shard.getThreadPool(),
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
+
+        final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = handler.createTransfer(
+            shard.store(),
+            filesToSend,
+            translogOps,
+            new ActionListener<Void>() {
+                @Override
+                public void onResponse(Void unused) {
+                    // do nothing here, we will just resolve in test.
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    assertEquals(CancellableThreads.ExecutionCancelledException.class, e.getClass());
+                    countDownLatch.countDown();
+                }
+            }
+        );
+
+        // start the transfer
+        transfer.start();
+        countDownLatch.await(30, TimeUnit.SECONDS);
+        verify(chunkWriter, times(1)).writeFileChunk(any(), anyLong(), any(), anyBoolean(), anyInt(), any());
+        IOUtils.close(transfer);
+    }
+
+    public void testSendFiles_CorruptIndexException() throws Exception {
+        final CancellableThreads cancellableThreads = new CancellableThreads();
+        SegmentFileTransferHandler handler = new SegmentFileTransferHandler(
+            shard,
+            targetNode,
+            mock(FileChunkWriter.class),
+            logger,
+            shard.getThreadPool(),
+            cancellableThreads,
+            fileChunkSizeInBytes,
+            maxConcurrentFileChunks
+        );
+        final StoreFileMetadata SEGMENTS_FILE = new StoreFileMetadata(
+            IndexFileNames.SEGMENTS,
+            1L,
+            "0",
+            org.apache.lucene.util.Version.LATEST
+        );
+
+        doNothing().when(shard).failShard(anyString(), any());
+        assertThrows(CorruptIndexException.class, () -> {
+            handler.handleErrorOnSendFiles(
+                shard.store(),
+                new CorruptIndexException("test", "test"),
+                new StoreFileMetadata[] { SEGMENTS_FILE }
+            );
+        });
+
+        verify(shard, times(1)).failShard(any(), any());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceHandlerTests.java b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceHandlerTests.java
new file mode 100644
index 0000000000000..d586767290797
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceHandlerTests.java
@@ -0,0 +1,259 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.recovery.FileChunkWriter;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.CopyState;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.mockito.Mockito;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+public class SegmentReplicationSourceHandlerTests extends IndexShardTestCase {
+
+    private final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);
+    private DiscoveryNode replicaDiscoveryNode;
+    private IndexShard primary;
+    private IndexShard replica;
+
+    private FileChunkWriter chunkWriter;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, "SEGMENT").put(Settings.EMPTY).build();
+        primary = newStartedShard(true, settings);
+        replica = newShard(false, settings, new NRTReplicationEngineFactory());
+        recoverReplica(replica, primary, true);
+        replicaDiscoveryNode = replica.recoveryState().getTargetNode();
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        closeShards(primary, replica);
+        super.tearDown();
+    }
+
+    public void testSendFiles() throws IOException {
+        chunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> listener.onResponse(null);
+
+        final ReplicationCheckpoint latestReplicationCheckpoint = primary.getLatestReplicationCheckpoint();
+        final CopyState copyState = new CopyState(latestReplicationCheckpoint, primary);
+        SegmentReplicationSourceHandler handler = new SegmentReplicationSourceHandler(
+            localNode,
+            chunkWriter,
+            threadPool,
+            copyState,
+            replica.routingEntry().allocationId().getId(),
+            5000,
+            1
+        );
+
+        final List<StoreFileMetadata> expectedFiles = List.copyOf(copyState.getMetadataMap().values());
+
+        final GetSegmentFilesRequest getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            expectedFiles,
+            latestReplicationCheckpoint
+        );
+
+        handler.sendFiles(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                MatcherAssert.assertThat(getSegmentFilesResponse.files, Matchers.containsInAnyOrder(expectedFiles.toArray()));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                Assert.fail();
+            }
+        });
+    }
+
+    public void testSendFiles_emptyRequest() throws IOException {
+        chunkWriter = mock(FileChunkWriter.class);
+
+        final ReplicationCheckpoint latestReplicationCheckpoint = primary.getLatestReplicationCheckpoint();
+        final CopyState copyState = new CopyState(latestReplicationCheckpoint, primary);
+        SegmentReplicationSourceHandler handler = new SegmentReplicationSourceHandler(
+            localNode,
+            chunkWriter,
+            threadPool,
+            copyState,
+            replica.routingEntry().allocationId().getId(),
+            5000,
+            1
+        );
+
+        final GetSegmentFilesRequest getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            Collections.emptyList(),
+            latestReplicationCheckpoint
+        );
+
+        handler.sendFiles(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                assertTrue(getSegmentFilesResponse.files.isEmpty());
+                Mockito.verifyNoInteractions(chunkWriter);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                Assert.fail();
+            }
+        });
+    }
+
+    public void testSendFileFails() throws IOException {
+        // index some docs on the primary so a segment is created.
+        indexDoc(primary, "1", "{\"foo\" : \"baz\"}", MediaTypeRegistry.JSON, "foobar");
+        primary.refresh("Test");
+        chunkWriter = (fileMetadata, position, content, lastChunk, totalTranslogOps, listener) -> listener.onFailure(
+            new OpenSearchException("Test")
+        );
+
+        final ReplicationCheckpoint latestReplicationCheckpoint = primary.getLatestReplicationCheckpoint();
+        final CopyState copyState = new CopyState(latestReplicationCheckpoint, primary);
+        SegmentReplicationSourceHandler handler = new SegmentReplicationSourceHandler(
+            localNode,
+            chunkWriter,
+            threadPool,
+            copyState,
+            primary.routingEntry().allocationId().getId(),
+            5000,
+            1
+        );
+
+        final List<StoreFileMetadata> expectedFiles = List.copyOf(copyState.getMetadataMap().values());
+
+        final GetSegmentFilesRequest getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            expectedFiles,
+            latestReplicationCheckpoint
+        );
+
+        handler.sendFiles(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(e.getClass(), OpenSearchException.class);
+            }
+        });
+        copyState.decRef();
+    }
+
+    public void testReplicationAlreadyRunning() throws IOException {
+        chunkWriter = mock(FileChunkWriter.class);
+
+        final ReplicationCheckpoint latestReplicationCheckpoint = primary.getLatestReplicationCheckpoint();
+        final CopyState copyState = new CopyState(latestReplicationCheckpoint, primary);
+        SegmentReplicationSourceHandler handler = new SegmentReplicationSourceHandler(
+            localNode,
+            chunkWriter,
+            threadPool,
+            copyState,
+            replica.routingEntry().allocationId().getId(),
+            5000,
+            1
+        );
+
+        final List<StoreFileMetadata> expectedFiles = List.of(new StoreFileMetadata("_0.si", 20, "test", Version.CURRENT.luceneVersion));
+
+        final GetSegmentFilesRequest getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            expectedFiles,
+            latestReplicationCheckpoint
+        );
+
+        handler.sendFiles(getSegmentFilesRequest, mock(ActionListener.class));
+        Assert.assertThrows(OpenSearchException.class, () -> { handler.sendFiles(getSegmentFilesRequest, mock(ActionListener.class)); });
+    }
+
+    public void testCancelReplication() throws IOException, InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        chunkWriter = mock(FileChunkWriter.class);
+
+        final ReplicationCheckpoint latestReplicationCheckpoint = primary.getLatestReplicationCheckpoint();
+        final CopyState copyState = new CopyState(latestReplicationCheckpoint, primary);
+        SegmentReplicationSourceHandler handler = new SegmentReplicationSourceHandler(
+            localNode,
+            chunkWriter,
+            threadPool,
+            copyState,
+            primary.routingEntry().allocationId().getId(),
+            5000,
+            1
+        );
+
+        final List<StoreFileMetadata> expectedFiles = List.of(new StoreFileMetadata("_0.si", 20, "test", Version.CURRENT.luceneVersion));
+        final GetSegmentFilesRequest getSegmentFilesRequest = new GetSegmentFilesRequest(
+            1L,
+            replica.routingEntry().allocationId().getId(),
+            replicaDiscoveryNode,
+            expectedFiles,
+            latestReplicationCheckpoint
+        );
+
+        // cancel before xfer starts. Cancels during copy will be tested in SegmentFileTransferHandlerTests, that uses the same
+        // cancellableThreads.
+        handler.cancel("test");
+        handler.sendFiles(getSegmentFilesRequest, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse getSegmentFilesResponse) {
+                Assert.fail("Expected failure.");
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(CancellableThreads.ExecutionCancelledException.class, e.getClass());
+                latch.countDown();
+            }
+        });
+        latch.await(2, TimeUnit.SECONDS);
+        verify(chunkWriter, times(1)).cancel();
+        assertEquals("listener should have resolved with failure", 0, latch.getCount());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceServiceTests.java b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceServiceTests.java
new file mode 100644
index 0000000000000..8f84053f2618e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationSourceServiceTests.java
@@ -0,0 +1,295 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.codecs.Codec;
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.ReplicationGroup;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.CopyStateTests;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportResponseHandler;
+import org.opensearch.transport.TransportService;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_REPLICATION_TYPE_SETTING;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationSourceServiceTests extends OpenSearchTestCase {
+
+    private ReplicationCheckpoint testCheckpoint;
+    private TestThreadPool testThreadPool;
+    private TransportService transportService;
+    private DiscoveryNode localNode;
+    private SegmentReplicationSourceService segmentReplicationSourceService;
+    private OngoingSegmentReplications ongoingSegmentReplications;
+    private IndexShard mockIndexShard;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        // setup mocks
+        mockIndexShard = CopyStateTests.createMockIndexShard();
+        ShardId testShardId = mockIndexShard.shardId();
+        IndicesService mockIndicesService = mock(IndicesService.class);
+        IndexService mockIndexService = mock(IndexService.class);
+        when(mockIndicesService.iterator()).thenReturn(List.of(mockIndexService).iterator());
+        when(mockIndicesService.indexServiceSafe(testShardId.getIndex())).thenReturn(mockIndexService);
+        when(mockIndexService.getShard(testShardId.id())).thenReturn(mockIndexShard);
+        when(mockIndexService.iterator()).thenReturn(List.of(mockIndexShard).iterator());
+        final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(
+            "index",
+            Settings.builder().put(INDEX_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT).build()
+        );
+        when(mockIndexService.getIndexSettings()).thenReturn(indexSettings);
+        final ShardRouting routing = mock(ShardRouting.class);
+        when(routing.primary()).thenReturn(true);
+        when(mockIndexShard.routingEntry()).thenReturn(routing);
+        when(mockIndexShard.isPrimaryMode()).thenReturn(true);
+        final ReplicationGroup replicationGroup = mock(ReplicationGroup.class);
+        when(mockIndexShard.getReplicationGroup()).thenReturn(replicationGroup);
+        when(replicationGroup.getInSyncAllocationIds()).thenReturn(Collections.emptySet());
+        // This mirrors the creation of the ReplicationCheckpoint inside CopyState
+        testCheckpoint = new ReplicationCheckpoint(
+            testShardId,
+            mockIndexShard.getOperationPrimaryTerm(),
+            0L,
+            0L,
+            Codec.getDefault().getName()
+        );
+        testThreadPool = new TestThreadPool("test", Settings.EMPTY);
+        CapturingTransport transport = new CapturingTransport();
+        localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            testThreadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> localNode,
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        final Settings settings = Settings.builder().put("node.name", SegmentReplicationTargetServiceTests.class.getSimpleName()).build();
+        final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        final RecoverySettings recoverySettings = new RecoverySettings(settings, clusterSettings);
+
+        ongoingSegmentReplications = spy(new OngoingSegmentReplications(mockIndicesService, recoverySettings));
+        segmentReplicationSourceService = new SegmentReplicationSourceService(
+            mockIndicesService,
+            transportService,
+            recoverySettings,
+            ongoingSegmentReplications
+        );
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        ThreadPool.terminate(testThreadPool, 30, TimeUnit.SECONDS);
+        testThreadPool = null;
+        super.tearDown();
+    }
+
+    public void testGetSegmentFiles() {
+        final GetSegmentFilesRequest request = new GetSegmentFilesRequest(
+            1,
+            "allocationId",
+            localNode,
+            Collections.emptyList(),
+            testCheckpoint
+        );
+        executeGetSegmentFiles(request, new ActionListener<>() {
+            @Override
+            public void onResponse(GetSegmentFilesResponse response) {
+                assertEquals(0, response.files.size());
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("unexpected exception: " + e);
+            }
+        });
+    }
+
+    public void testUpdateVisibleCheckpoint() {
+        UpdateVisibleCheckpointRequest request = new UpdateVisibleCheckpointRequest(
+            0L,
+            "",
+            mockIndexShard.shardId(),
+            localNode,
+            testCheckpoint
+        );
+        executeUpdateVisibleCheckpoint(request, new ActionListener<>() {
+            @Override
+            public void onResponse(TransportResponse transportResponse) {
+                assertTrue(TransportResponse.Empty.INSTANCE.equals(transportResponse));
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("unexpected exception: " + e);
+            }
+        });
+    }
+
+    public void testCheckpointInfo() {
+        executeGetCheckpointInfo(new ActionListener<>() {
+            @Override
+            public void onResponse(CheckpointInfoResponse response) {
+                assertEquals(testCheckpoint, response.getCheckpoint());
+                assertNotNull(response.getInfosBytes());
+                assertEquals(1, response.getMetadataMap().size());
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                fail("unexpected exception: " + e);
+            }
+        });
+    }
+
+    public void testPrimaryClearsOutOfSyncIds() {
+        final ClusterChangedEvent mock = mock(ClusterChangedEvent.class);
+        when(mock.routingTableChanged()).thenReturn(true);
+        segmentReplicationSourceService.clusterChanged(mock);
+        verify(ongoingSegmentReplications, times(1)).clearOutOfSyncIds(any(), any());
+    }
+
+    private void executeGetCheckpointInfo(ActionListener<CheckpointInfoResponse> listener) {
+        final CheckpointInfoRequest request = new CheckpointInfoRequest(1L, "testAllocationId", localNode, testCheckpoint);
+        transportService.sendRequest(
+            localNode,
+            SegmentReplicationSourceService.Actions.GET_CHECKPOINT_INFO,
+            request,
+            new TransportResponseHandler<CheckpointInfoResponse>() {
+                @Override
+                public void handleResponse(CheckpointInfoResponse response) {
+                    listener.onResponse(response);
+                }
+
+                @Override
+                public void handleException(TransportException e) {
+                    listener.onFailure(e);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.SAME;
+                }
+
+                @Override
+                public CheckpointInfoResponse read(StreamInput in) throws IOException {
+                    return new CheckpointInfoResponse(in);
+                }
+            }
+        );
+    }
+
+    private void executeGetSegmentFiles(GetSegmentFilesRequest request, ActionListener<GetSegmentFilesResponse> listener) {
+        transportService.sendRequest(
+            localNode,
+            SegmentReplicationSourceService.Actions.GET_SEGMENT_FILES,
+            request,
+            new TransportResponseHandler<GetSegmentFilesResponse>() {
+                @Override
+                public void handleResponse(GetSegmentFilesResponse response) {
+                    listener.onResponse(response);
+                }
+
+                @Override
+                public void handleException(TransportException e) {
+                    listener.onFailure(e);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.SAME;
+                }
+
+                @Override
+                public GetSegmentFilesResponse read(StreamInput in) throws IOException {
+                    return new GetSegmentFilesResponse(in);
+                }
+            }
+        );
+    }
+
+    private void executeUpdateVisibleCheckpoint(UpdateVisibleCheckpointRequest request, ActionListener<TransportResponse> listener) {
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                UpdateVisibleCheckpointRequest newRequest = new UpdateVisibleCheckpointRequest(in);
+                assertTrue(newRequest.getCheckpoint().equals(request.getCheckpoint()));
+                assertTrue(newRequest.getTargetAllocationId().equals(request.getTargetAllocationId()));
+            }
+        } catch (IOException e) {
+            fail("Failed to parse UpdateVisibleCheckpointRequest " + e);
+        }
+
+        transportService.sendRequest(
+            localNode,
+            SegmentReplicationSourceService.Actions.UPDATE_VISIBLE_CHECKPOINT,
+            request,
+            new TransportResponseHandler<>() {
+                @Override
+                public void handleResponse(TransportResponse response) {
+                    listener.onResponse(TransportResponse.Empty.INSTANCE);
+                }
+
+                @Override
+                public void handleException(TransportException e) {
+                    listener.onFailure(e);
+                }
+
+                @Override
+                public String executor() {
+                    return ThreadPool.Names.SAME;
+                }
+
+                @Override
+                public CheckpointInfoResponse read(StreamInput in) throws IOException {
+                    return new CheckpointInfoResponse(in);
+                }
+            }
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetServiceTests.java b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetServiceTests.java
new file mode 100644
index 0000000000000..6deccde1afa48
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetServiceTests.java
@@ -0,0 +1,617 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.store.AlreadyClosedException;
+import org.opensearch.OpenSearchException;
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.cluster.routing.RoutingTable;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.CancellableThreads;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.replication.TestReplicationSource;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.ForceSyncRequest;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.EmptyTransportResponseHandler;
+import org.opensearch.transport.TransportRequestOptions;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationTargetServiceTests extends IndexShardTestCase {
+
+    private IndexShard replicaShard;
+    private IndexShard primaryShard;
+    private ReplicationCheckpoint checkpoint;
+    private SegmentReplicationTargetService sut;
+    private ReplicationCheckpoint aheadCheckpoint;
+
+    private ReplicationCheckpoint newPrimaryCheckpoint;
+
+    private TransportService transportService;
+    private TestThreadPool testThreadPool;
+    private DiscoveryNode localNode;
+
+    private IndicesService indicesService;
+
+    private SegmentReplicationState state;
+    private ReplicationCheckpoint initialCheckpoint;
+
+    private static final long TRANSPORT_TIMEOUT = 30000;// 30sec
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put("node.name", SegmentReplicationTargetServiceTests.class.getSimpleName())
+            .build();
+        primaryShard = newStartedShard(true, settings);
+        String primaryCodec = primaryShard.getLatestReplicationCheckpoint().getCodec();
+        replicaShard = newShard(false, settings, new NRTReplicationEngineFactory());
+        recoverReplica(replicaShard, primaryShard, true, getReplicationFunc(replicaShard));
+        checkpoint = new ReplicationCheckpoint(
+            replicaShard.shardId(),
+            0L,
+            0L,
+            0L,
+            replicaShard.getLatestReplicationCheckpoint().getCodec()
+        );
+
+        testThreadPool = new TestThreadPool("test", Settings.EMPTY);
+        localNode = new DiscoveryNode(
+            primaryShard.getReplicationGroup().getRoutingTable().primaryShard().currentNodeId(),
+            buildNewFakeTransportAddress(),
+            Version.CURRENT
+        );
+        CapturingTransport transport = new CapturingTransport();
+        transportService = transport.createTransportService(
+            Settings.EMPTY,
+            testThreadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> localNode,
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+
+        indicesService = mock(IndicesService.class);
+        ClusterService clusterService = mock(ClusterService.class);
+        ClusterState clusterState = mock(ClusterState.class);
+        RoutingTable mockRoutingTable = mock(RoutingTable.class);
+        when(clusterService.state()).thenReturn(clusterState);
+        when(clusterState.routingTable()).thenReturn(mockRoutingTable);
+        when(mockRoutingTable.shardRoutingTable(any())).thenReturn(primaryShard.getReplicationGroup().getRoutingTable());
+
+        when(clusterState.nodes()).thenReturn(DiscoveryNodes.builder().add(localNode).build());
+        sut = prepareForReplication(primaryShard, replicaShard, transportService, indicesService, clusterService);
+        initialCheckpoint = primaryShard.getLatestReplicationCheckpoint();
+        aheadCheckpoint = new ReplicationCheckpoint(
+            initialCheckpoint.getShardId(),
+            initialCheckpoint.getPrimaryTerm(),
+            initialCheckpoint.getSegmentsGen(),
+            initialCheckpoint.getSegmentInfosVersion() + 1,
+            primaryCodec
+        );
+        newPrimaryCheckpoint = new ReplicationCheckpoint(
+            initialCheckpoint.getShardId(),
+            initialCheckpoint.getPrimaryTerm() + 1,
+            initialCheckpoint.getSegmentsGen(),
+            initialCheckpoint.getSegmentInfosVersion() + 1,
+            primaryCodec
+        );
+
+        state = new SegmentReplicationState(
+            replicaShard.routingEntry(),
+            new ReplicationLuceneIndex(),
+            0L,
+            "",
+            new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT)
+        );
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        closeShards(primaryShard, replicaShard);
+        ThreadPool.terminate(testThreadPool, 30, TimeUnit.SECONDS);
+        testThreadPool = null;
+        super.tearDown();
+    }
+
+    public void testsSuccessfulReplication_listenerCompletes() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        sut.startReplication(
+            replicaShard,
+            primaryShard.getLatestReplicationCheckpoint(),
+            new SegmentReplicationTargetService.SegmentReplicationListener() {
+                @Override
+                public void onReplicationDone(SegmentReplicationState state) {
+                    assertEquals(SegmentReplicationState.Stage.DONE, state.getStage());
+                    latch.countDown();
+                }
+
+                @Override
+                public void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                    logger.error("Unexpected error", e);
+                    Assert.fail("Test should succeed");
+                }
+            }
+        );
+        latch.await(2, TimeUnit.SECONDS);
+        assertEquals(0, latch.getCount());
+    }
+
+    public void testReplicationFails() throws InterruptedException {
+        CountDownLatch latch = new CountDownLatch(1);
+        final OpenSearchException expectedError = new OpenSearchException("Fail");
+        SegmentReplicationSource source = new TestReplicationSource() {
+
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onFailure(expectedError);
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                Assert.fail("Should not be called");
+            }
+        };
+        final SegmentReplicationTarget target = new SegmentReplicationTarget(
+            replicaShard,
+            primaryShard.getLatestReplicationCheckpoint(),
+            source,
+            new SegmentReplicationTargetService.SegmentReplicationListener() {
+                @Override
+                public void onReplicationDone(SegmentReplicationState state) {
+                    Assert.fail();
+                }
+
+                @Override
+                public void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                    // failures leave state object in last entered stage.
+                    assertEquals(SegmentReplicationState.Stage.GET_CHECKPOINT_INFO, state.getStage());
+                    assertEquals(expectedError, e.getCause());
+                    latch.countDown();
+                }
+            }
+        );
+        sut.startReplication(target);
+        latch.await(2, TimeUnit.SECONDS);
+        assertEquals(0, latch.getCount());
+    }
+
+    public void testAlreadyOnNewCheckpoint() {
+        SegmentReplicationTargetService spy = spy(sut);
+        spy.onNewCheckpoint(replicaShard.getLatestReplicationCheckpoint(), replicaShard);
+        verify(spy, times(0)).startReplication(any(), any(), any());
+    }
+
+    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/8928")
+    public void testShardAlreadyReplicating() {
+        CountDownLatch blockGetCheckpointMetadata = new CountDownLatch(1);
+        SegmentReplicationSource source = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                try {
+                    blockGetCheckpointMetadata.await();
+                    final CopyState copyState = new CopyState(
+                        ReplicationCheckpoint.empty(primaryShard.shardId(), primaryShard.getLatestReplicationCheckpoint().getCodec()),
+                        primaryShard
+                    );
+                    listener.onResponse(
+                        new CheckpointInfoResponse(copyState.getCheckpoint(), copyState.getMetadataMap(), copyState.getInfosBytes())
+                    );
+                } catch (InterruptedException | IOException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(Collections.emptyList()));
+            }
+        };
+        final SegmentReplicationTarget target = spy(
+            new SegmentReplicationTarget(
+                replicaShard,
+                primaryShard.getLatestReplicationCheckpoint(),
+                source,
+                mock(SegmentReplicationTargetService.SegmentReplicationListener.class)
+            )
+        );
+
+        final SegmentReplicationTargetService spy = spy(sut);
+        doReturn(false).when(spy).processLatestReceivedCheckpoint(eq(replicaShard), any());
+        // Start first round of segment replication.
+        spy.startReplication(target);
+
+        // Start second round of segment replication, this should fail to start as first round is still in-progress
+        spy.onNewCheckpoint(newPrimaryCheckpoint, replicaShard);
+        verify(spy, times(1)).processLatestReceivedCheckpoint(eq(replicaShard), any());
+        blockGetCheckpointMetadata.countDown();
+    }
+
+    public void testOnNewCheckpointFromNewPrimaryCancelOngoingReplication() throws InterruptedException {
+        // Create a spy of Target Service so that we can verify invocation of startReplication call with specific checkpoint on it.
+        SegmentReplicationTargetService serviceSpy = spy(sut);
+        doNothing().when(serviceSpy).updateVisibleCheckpoint(anyLong(), any());
+        // skip post replication actions so we can assert execution counts. This will continue to process bc replica's pterm is not advanced
+        // post replication.
+        doReturn(true).when(serviceSpy).processLatestReceivedCheckpoint(any(), any());
+        // Create a Mockito spy of target to stub response of few method calls.
+
+        CountDownLatch latch = new CountDownLatch(1);
+        SegmentReplicationSource source = new TestReplicationSource() {
+
+            ActionListener<CheckpointInfoResponse> listener;
+
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                // set the listener, we will only fail it once we cancel the source.
+                this.listener = listener;
+                latch.countDown();
+                // do not resolve this listener yet, wait for cancel to hit.
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                Assert.fail("Unreachable");
+            }
+
+            @Override
+            public void cancel() {
+                // simulate listener resolving, but only after we have issued a cancel from beforeIndexShardClosed .
+                final RuntimeException exception = new CancellableThreads.ExecutionCancelledException("retryable action was cancelled");
+                listener.onFailure(exception);
+            }
+        };
+
+        final ReplicationCheckpoint updatedCheckpoint = new ReplicationCheckpoint(
+            initialCheckpoint.getShardId(),
+            initialCheckpoint.getPrimaryTerm(),
+            initialCheckpoint.getSegmentsGen(),
+            initialCheckpoint.getSegmentInfosVersion() + 1,
+            primaryShard.getDefaultCodecName()
+        );
+
+        final SegmentReplicationTarget targetSpy = spy(
+            new SegmentReplicationTarget(
+                replicaShard,
+                updatedCheckpoint,
+                source,
+                mock(SegmentReplicationTargetService.SegmentReplicationListener.class)
+            )
+        );
+
+        // start replication. This adds the target to on-ongoing replication collection
+        serviceSpy.startReplication(targetSpy);
+
+        // wait until we get to getCheckpoint step.
+        latch.await();
+
+        // new checkpoint arrives with higher pterm.
+        serviceSpy.onNewCheckpoint(newPrimaryCheckpoint, replicaShard);
+
+        // ensure the old target is cancelled. and new iteration kicks off.
+        verify(targetSpy, times(1)).cancel("Cancelling stuck target after new primary");
+        verify(serviceSpy, times(1)).startReplication(eq(replicaShard), any(), any());
+    }
+
+    public void testNewCheckpointBehindCurrentCheckpoint() {
+        SegmentReplicationTargetService spy = spy(sut);
+        spy.onNewCheckpoint(checkpoint, replicaShard);
+        verify(spy, times(0)).startReplication(any(), any(), any());
+    }
+
+    public void testShardNotStarted() throws IOException {
+        SegmentReplicationTargetService spy = spy(sut);
+        IndexShard shard = newShard(false);
+        spy.onNewCheckpoint(checkpoint, shard);
+        verify(spy, times(0)).startReplication(any(), any(), any());
+        closeShards(shard);
+    }
+
+    /**
+     * here we are starting a new shard in PrimaryMode and testing that we don't process a checkpoint on shard when it is in PrimaryMode.
+     */
+    public void testRejectCheckpointOnShardPrimaryMode() throws IOException {
+        SegmentReplicationTargetService spy = spy(sut);
+
+        // Starting a new shard in PrimaryMode.
+        IndexShard primaryShard = newStartedShard(true);
+        IndexShard spyShard = spy(primaryShard);
+        spy.onNewCheckpoint(aheadCheckpoint, spyShard);
+
+        // Verify that checkpoint is not processed as shard is in PrimaryMode.
+        verify(spy, times(0)).startReplication(any(), any(), any());
+        closeShards(primaryShard);
+    }
+
+    public void testAfterIndexShardStartedDoesNothingForDocrepIndex() throws IOException {
+        SegmentReplicationTargetService spy = spy(sut);
+        final IndexShard indexShard = newStartedShard();
+        spy.afterIndexShardStarted(indexShard);
+        verify(spy, times(0)).processLatestReceivedCheckpoint(eq(replicaShard), any());
+        closeShards(indexShard);
+    }
+
+    public void testAfterIndexShardStartedProcessesLatestReceivedCheckpoint() {
+        sut.updateLatestReceivedCheckpoint(aheadCheckpoint, replicaShard);
+        SegmentReplicationTargetService spy = spy(sut);
+        doNothing().when(spy).onNewCheckpoint(any(), any());
+        spy.afterIndexShardStarted(replicaShard);
+        verify(spy, times(1)).processLatestReceivedCheckpoint(eq(replicaShard), any());
+    }
+
+    public void testStartReplicationListenerSuccess() throws InterruptedException {
+        sut.updateLatestReceivedCheckpoint(aheadCheckpoint, replicaShard);
+        SegmentReplicationTargetService spy = spy(sut);
+        CountDownLatch latch = new CountDownLatch(1);
+        doAnswer(i -> {
+            ((SegmentReplicationTargetService.SegmentReplicationListener) i.getArgument(2)).onReplicationDone(state);
+            latch.countDown();
+            return null;
+        }).when(spy).startReplication(any(), any(), any());
+        doNothing().when(spy).updateVisibleCheckpoint(eq(0L), any());
+        spy.afterIndexShardStarted(replicaShard);
+
+        latch.await(2, TimeUnit.SECONDS);
+        verify(spy, (atLeastOnce())).updateVisibleCheckpoint(eq(0L), eq(replicaShard));
+    }
+
+    public void testStartReplicationListenerFailure() throws InterruptedException {
+        sut.updateLatestReceivedCheckpoint(aheadCheckpoint, replicaShard);
+        SegmentReplicationTargetService spy = spy(sut);
+        CountDownLatch latch = new CountDownLatch(1);
+        doAnswer(i -> {
+            ((SegmentReplicationTargetService.SegmentReplicationListener) i.getArgument(2)).onReplicationFailure(
+                state,
+                new ReplicationFailedException(replicaShard, null),
+                false
+            );
+            latch.countDown();
+            return null;
+        }).when(spy).startReplication(any(), any(), any());
+        doNothing().when(spy).updateVisibleCheckpoint(eq(0L), any());
+        spy.afterIndexShardStarted(replicaShard);
+
+        latch.await(2, TimeUnit.SECONDS);
+        verify(spy, (never())).updateVisibleCheckpoint(eq(0L), eq(replicaShard));
+    }
+
+    public void testDoNotProcessLatestCheckpointIfItIsbehind() {
+        sut.updateLatestReceivedCheckpoint(replicaShard.getLatestReplicationCheckpoint(), replicaShard);
+        assertFalse(sut.processLatestReceivedCheckpoint(replicaShard, null));
+    }
+
+    public void testOnNewCheckpointInvokedOnClosedShardDoesNothing() throws IOException {
+        closeShards(replicaShard);
+        SegmentReplicationTargetService spy = spy(sut);
+        spy.onNewCheckpoint(aheadCheckpoint, replicaShard);
+        verify(spy, times(0)).updateLatestReceivedCheckpoint(any(), any());
+    }
+
+    public void testBeforeIndexShardClosed_DoesNothingForDocRepIndex() throws IOException {
+        final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+        final IndicesService indicesService = mock(IndicesService.class);
+        final ClusterService clusterService = mock(ClusterService.class);
+        final ReplicationCollection<SegmentReplicationTarget> ongoingReplications = mock(ReplicationCollection.class);
+        final SegmentReplicationTargetService targetService = new SegmentReplicationTargetService(
+            threadPool,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            mock(TransportService.class),
+            sourceFactory,
+            indicesService,
+            clusterService,
+            ongoingReplications
+        );
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+        IndexShard shard = newStartedShard(false, settings);
+        targetService.beforeIndexShardClosed(shard.shardId(), shard, shard.indexSettings().getSettings());
+        verifyNoInteractions(ongoingReplications);
+        closeShards(shard);
+    }
+
+    public void testShardRoutingChanged_DoesNothingForDocRepIndex() throws IOException {
+        final SegmentReplicationSourceFactory sourceFactory = mock(SegmentReplicationSourceFactory.class);
+        final IndicesService indicesService = mock(IndicesService.class);
+        final ClusterService clusterService = mock(ClusterService.class);
+        final ReplicationCollection<SegmentReplicationTarget> ongoingReplications = mock(ReplicationCollection.class);
+        final SegmentReplicationTargetService targetService = new SegmentReplicationTargetService(
+            threadPool,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            mock(TransportService.class),
+            sourceFactory,
+            indicesService,
+            clusterService,
+            ongoingReplications
+        );
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build();
+        IndexShard shard = newStartedShard(false, settings);
+
+        targetService.shardRoutingChanged(shard, shard.routingEntry(), primaryShard.routingEntry());
+        verifyNoInteractions(ongoingReplications);
+        closeShards(shard);
+    }
+
+    public void testUpdateLatestReceivedCheckpoint() {
+        final SegmentReplicationTargetService spy = spy(sut);
+        sut.updateLatestReceivedCheckpoint(checkpoint, replicaShard);
+        sut.updateLatestReceivedCheckpoint(aheadCheckpoint, replicaShard);
+        assertEquals(sut.latestReceivedCheckpoint.get(replicaShard.shardId()), aheadCheckpoint);
+    }
+
+    public void testForceSegmentSyncHandler() throws Exception {
+        ForceSyncRequest forceSyncRequest = new ForceSyncRequest(1L, 1L, replicaShard.shardId());
+        when(indicesService.getShardOrNull(forceSyncRequest.getShardId())).thenReturn(replicaShard);
+        TransportResponse response = transportService.submitRequest(
+            localNode,
+            SegmentReplicationTargetService.Actions.FORCE_SYNC,
+            forceSyncRequest,
+            TransportRequestOptions.builder().withTimeout(TRANSPORT_TIMEOUT).build(),
+            EmptyTransportResponseHandler.INSTANCE_SAME
+        ).txGet();
+        assertEquals(TransportResponse.Empty.INSTANCE, response);
+    }
+
+    public void testForceSegmentSyncHandlerWithFailure() throws Exception {
+        allowShardFailures();
+        IndexShard spyReplicaShard = spy(replicaShard);
+        ForceSyncRequest forceSyncRequest = new ForceSyncRequest(1L, 1L, replicaShard.shardId());
+        when(indicesService.getShardOrNull(forceSyncRequest.getShardId())).thenReturn(spyReplicaShard);
+        IOException exception = new IOException("dummy failure");
+        doThrow(exception).when(spyReplicaShard).finalizeReplication(any());
+
+        // prevent shard failure to avoid test setup assertion
+        doNothing().when(spyReplicaShard).failShard(eq("replication failure"), any());
+        Exception finalizeException = expectThrows(Exception.class, () -> {
+            transportService.submitRequest(
+                localNode,
+                SegmentReplicationTargetService.Actions.FORCE_SYNC,
+                forceSyncRequest,
+                TransportRequestOptions.builder().withTimeout(TRANSPORT_TIMEOUT).build(),
+                EmptyTransportResponseHandler.INSTANCE_SAME
+            ).txGet();
+        });
+        Throwable nestedException = finalizeException.getCause().getCause();
+        assertTrue(nestedException instanceof IOException);
+        assertTrue(nestedException.getMessage().contains("dummy failure"));
+    }
+
+    public void testForceSync_ShardDoesNotExist() {
+        ForceSyncRequest forceSyncRequest = new ForceSyncRequest(1L, 1L, new ShardId("no", "", 0));
+        when(indicesService.getShardOrNull(forceSyncRequest.getShardId())).thenReturn(null);
+        transportService.submitRequest(
+            localNode,
+            SegmentReplicationTargetService.Actions.FORCE_SYNC,
+            forceSyncRequest,
+            TransportRequestOptions.builder().withTimeout(TRANSPORT_TIMEOUT).build(),
+            EmptyTransportResponseHandler.INSTANCE_SAME
+        ).txGet();
+    }
+
+    public void testForceSegmentSyncHandlerWithFailure_AlreadyClosedException_swallowed() throws Exception {
+        IndexShard spyReplicaShard = spy(replicaShard);
+        ForceSyncRequest forceSyncRequest = new ForceSyncRequest(1L, 1L, replicaShard.shardId());
+        when(indicesService.getShardOrNull(forceSyncRequest.getShardId())).thenReturn(spyReplicaShard);
+
+        AlreadyClosedException exception = new AlreadyClosedException("shard closed");
+        doThrow(exception).when(spyReplicaShard).finalizeReplication(any());
+
+        // prevent shard failure to avoid test setup assertion
+        doNothing().when(spyReplicaShard).failShard(eq("replication failure"), any());
+        transportService.submitRequest(
+            localNode,
+            SegmentReplicationTargetService.Actions.FORCE_SYNC,
+            forceSyncRequest,
+            TransportRequestOptions.builder().withTimeout(TRANSPORT_TIMEOUT).build(),
+            EmptyTransportResponseHandler.INSTANCE_SAME
+        ).txGet();
+    }
+
+    public void testTargetCancelledBeforeStartInvoked() {
+        final SegmentReplicationTarget target = new SegmentReplicationTarget(
+            replicaShard,
+            primaryShard.getLatestReplicationCheckpoint(),
+            mock(SegmentReplicationSource.class),
+            new SegmentReplicationTargetService.SegmentReplicationListener() {
+                @Override
+                public void onReplicationDone(SegmentReplicationState state) {
+                    Assert.fail();
+                }
+
+                @Override
+                public void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                    // failures leave state object in last entered stage.
+                    assertEquals(SegmentReplicationState.Stage.GET_CHECKPOINT_INFO, state.getStage());
+                    assertTrue(e.getCause() instanceof CancellableThreads.ExecutionCancelledException);
+                }
+            }
+        );
+        target.cancel("test");
+        sut.startReplication(target);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetTests.java b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetTests.java
new file mode 100644
index 0000000000000..1192796566dcf
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/SegmentReplicationTargetTests.java
@@ -0,0 +1,498 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.IndexFormatTooNewException;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.store.ByteBuffersDataOutput;
+import org.apache.lucene.store.ByteBuffersIndexOutput;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.Version;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchCorruptionException;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
+import org.opensearch.index.replication.TestReplicationSource;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.StoreTests;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.test.DummyShardLock;
+import org.opensearch.test.IndexSettingsModule;
+import org.junit.Assert;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.NoSuchFileException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class SegmentReplicationTargetTests extends IndexShardTestCase {
+
+    private SegmentReplicationTarget segrepTarget;
+    private IndexShard indexShard, spyIndexShard;
+    private ReplicationCheckpoint repCheckpoint;
+    private ByteBuffersDataOutput buffer;
+
+    private static final String SEGMENT_NAME = "_0.si";
+    private static final StoreFileMetadata SEGMENT_FILE = new StoreFileMetadata(SEGMENT_NAME, 1L, "0", Version.LATEST);
+    private static final StoreFileMetadata SEGMENT_FILE_DIFF = new StoreFileMetadata(SEGMENT_NAME, 5L, "different", Version.LATEST);
+
+    private static final Map<String, StoreFileMetadata> SI_SNAPSHOT = Map.of(SEGMENT_FILE.name(), SEGMENT_FILE);
+
+    private static final Map<String, StoreFileMetadata> SI_SNAPSHOT_DIFFERENT = Map.of(SEGMENT_FILE_DIFF.name(), SEGMENT_FILE_DIFF);
+
+    private static final IndexSettings INDEX_SETTINGS = IndexSettingsModule.newIndexSettings(
+        "index",
+        Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT).build()
+    );
+
+    private SegmentInfos testSegmentInfos;
+
+    @Override
+    public void setUp() throws Exception {
+
+        super.setUp();
+        Settings indexSettings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+
+        indexShard = newStartedShard(false, indexSettings, new NRTReplicationEngineFactory());
+        spyIndexShard = spy(indexShard);
+
+        Mockito.doNothing().when(spyIndexShard).finalizeReplication(any(SegmentInfos.class));
+        testSegmentInfos = spyIndexShard.store().readLastCommittedSegmentsInfo();
+        buffer = new ByteBuffersDataOutput();
+        try (ByteBuffersIndexOutput indexOutput = new ByteBuffersIndexOutput(buffer, "", null)) {
+            testSegmentInfos.write(indexOutput);
+        }
+        repCheckpoint = new ReplicationCheckpoint(
+            spyIndexShard.shardId(),
+            spyIndexShard.getPendingPrimaryTerm(),
+            testSegmentInfos.getGeneration(),
+            testSegmentInfos.version,
+            indexShard.getLatestReplicationCheckpoint().getCodec()
+        );
+    }
+
+    public void testSuccessfulResponse_startReplication() {
+
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, SI_SNAPSHOT, buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                assertEquals(1, filesToFetch.size());
+                assert (filesToFetch.contains(SEGMENT_FILE));
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                try {
+                    verify(spyIndexShard, times(1)).finalizeReplication(any());
+                    segrepTarget.markAsDone();
+                } catch (IOException ex) {
+                    Assert.fail();
+                }
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Unexpected onFailure", e);
+                Assert.fail();
+            }
+        });
+    }
+
+    public void testFailureResponse_getCheckpointMetadata() {
+
+        Exception exception = new Exception("dummy failure");
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onFailure(exception);
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(exception, e.getCause().getCause());
+                segrepTarget.fail(new ReplicationFailedException(e), false);
+            }
+        });
+    }
+
+    public void testFailureResponse_getSegmentFiles() {
+
+        Exception exception = new Exception("dummy failure");
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, SI_SNAPSHOT, buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onFailure(exception);
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(exception, e.getCause().getCause());
+                segrepTarget.fail(new ReplicationFailedException(e), false);
+            }
+        });
+    }
+
+    public void testFailure_finalizeReplication_IOException() throws IOException {
+
+        IOException exception = new IOException("dummy failure");
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, SI_SNAPSHOT, buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+
+        doThrow(exception).when(spyIndexShard).finalizeReplication(any());
+
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(exception, e.getCause());
+                segrepTarget.fail(new ReplicationFailedException(e), false);
+            }
+        });
+    }
+
+    public void testFailure_finalizeReplication_IndexFormatException() throws IOException {
+
+        IndexFormatTooNewException exception = new IndexFormatTooNewException("string", 1, 2, 1);
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, SI_SNAPSHOT, buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+
+        doThrow(exception).when(spyIndexShard).finalizeReplication(any());
+
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertEquals(exception, e.getCause());
+                segrepTarget.fail(new ReplicationFailedException(e), false);
+            }
+        });
+    }
+
+    public void testFailure_differentSegmentFiles() throws IOException {
+
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, SI_SNAPSHOT, buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+        when(spyIndexShard.getSegmentMetadataMap()).thenReturn(SI_SNAPSHOT_DIFFERENT);
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                Assert.fail();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assertTrue(e instanceof OpenSearchCorruptionException);
+                assertTrue(e.getMessage().contains("has local copies of segments that differ from the primary"));
+                segrepTarget.fail(new ReplicationFailedException(e), false);
+            }
+        });
+    }
+
+    /**
+     * This tests ensures that new files generated on primary (due to delete operation) are not considered missing on replica
+     * @throws IOException
+     */
+    public void test_MissingFiles_NotCausingFailure() throws IOException {
+        int docCount = 1 + random().nextInt(10);
+        // Generate a list of MetadataSnapshot containing two elements. The second snapshot contains extra files
+        // generated due to delete operations. These two snapshots can then be used in test to mock the primary shard
+        // snapshot (2nd element which contains delete operations) and replica's existing snapshot (1st element).
+        List<Store.MetadataSnapshot> storeMetadataSnapshots = generateStoreMetadataSnapshot(docCount);
+
+        SegmentReplicationSource segrepSource = new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                listener.onResponse(new CheckpointInfoResponse(checkpoint, storeMetadataSnapshots.get(1).asMap(), buffer.toArrayCopy()));
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+        SegmentReplicationTargetService.SegmentReplicationListener segRepListener = mock(
+            SegmentReplicationTargetService.SegmentReplicationListener.class
+        );
+
+        segrepTarget = new SegmentReplicationTarget(spyIndexShard, repCheckpoint, segrepSource, segRepListener);
+        when(spyIndexShard.getSegmentMetadataMap()).thenReturn(storeMetadataSnapshots.get(0).asMap());
+        segrepTarget.startReplication(new ActionListener<Void>() {
+            @Override
+            public void onResponse(Void replicationResponse) {
+                logger.info("No error processing checkpoint info");
+                segrepTarget.markAsDone();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.error("Unexpected onFailure", e);
+                Assert.fail();
+            }
+        });
+    }
+
+    /**
+     * Generates a list of Store.MetadataSnapshot with two elements where second snapshot has extra files due to delete
+     * operation. A list of snapshots is returned so that identical files have same checksum.
+     * @param docCount
+     * @return
+     * @throws IOException
+     */
+    private List<Store.MetadataSnapshot> generateStoreMetadataSnapshot(int docCount) throws IOException {
+        List<Document> docList = new ArrayList<>();
+        for (int i = 0; i < docCount; i++) {
+            Document document = new Document();
+            String text = new String(new char[] { (char) (97 + i), (char) (97 + i) });
+            document.add(new StringField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
+            document.add(new TextField("str", text, Field.Store.YES));
+            docList.add(document);
+        }
+        long seed = random().nextLong();
+        Random random = new Random(seed);
+        IndexWriterConfig iwc = new IndexWriterConfig(new MockAnalyzer(random)).setCodec(TestUtil.getDefaultCodec());
+        iwc.setMergePolicy(NoMergePolicy.INSTANCE);
+        iwc.setUseCompoundFile(true);
+        final ShardId shardId = new ShardId("index", "_na_", 1);
+        Store store = new Store(shardId, INDEX_SETTINGS, StoreTests.newDirectory(random()), new DummyShardLock(shardId));
+        IndexWriter writer = new IndexWriter(store.directory(), iwc);
+        for (Document d : docList) {
+            writer.addDocument(d);
+        }
+        writer.commit();
+        Store.MetadataSnapshot storeMetadata = store.getMetadata();
+        // Delete one document to generate .liv file
+        writer.deleteDocuments(new Term("id", Integer.toString(random().nextInt(docCount))));
+        writer.commit();
+        Store.MetadataSnapshot storeMetadataWithDeletes = store.getMetadata();
+        deleteContent(store.directory());
+        writer.close();
+        store.close();
+        return Arrays.asList(storeMetadata, storeMetadataWithDeletes);
+    }
+
+    private static void deleteContent(Directory directory) throws IOException {
+        final String[] files = directory.listAll();
+        final List<IOException> exceptions = new ArrayList<>();
+        for (String file : files) {
+            try {
+                directory.deleteFile(file);
+            } catch (NoSuchFileException | FileNotFoundException e) {
+                // ignore
+            } catch (IOException e) {
+                exceptions.add(e);
+            }
+        }
+        ExceptionsHelper.rethrowAndSuppress(exceptions);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        closeShards(spyIndexShard, indexShard);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointActionTests.java b/server/src/test/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointActionTests.java
new file mode 100644
index 0000000000000..2cf006176022d
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/checkpoint/PublishCheckpointActionTests.java
@@ -0,0 +1,190 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.checkpoint;
+
+import org.apache.lucene.codecs.Codec;
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.ActionTestUtils;
+import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.action.support.replication.ReplicationMode;
+import org.opensearch.action.support.replication.TransportReplicationAction;
+import org.opensearch.cluster.action.shard.ShardStateAction;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.CapturingTransport;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+import java.util.Collections;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
+import static org.hamcrest.Matchers.sameInstance;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class PublishCheckpointActionTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+    private CapturingTransport transport;
+    private ClusterService clusterService;
+    private TransportService transportService;
+    private ShardStateAction shardStateAction;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        threadPool = new TestThreadPool(getClass().getName());
+        transport = new CapturingTransport();
+        clusterService = createClusterService(threadPool);
+        transportService = transport.createTransportService(
+            clusterService.getSettings(),
+            threadPool,
+            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
+            boundAddress -> clusterService.localNode(),
+            null,
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
+        );
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        shardStateAction = new ShardStateAction(clusterService, transportService, null, null, threadPool);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        try {
+            IOUtils.close(transportService, clusterService, transport);
+        } finally {
+            terminate(threadPool);
+        }
+        super.tearDown();
+    }
+
+    public void testPublishCheckpointActionOnPrimary() {
+        final IndicesService indicesService = mock(IndicesService.class);
+
+        final Index index = new Index("index", "uuid");
+        final IndexService indexService = mock(IndexService.class);
+        when(indicesService.indexServiceSafe(index)).thenReturn(indexService);
+
+        final int id = randomIntBetween(0, 4);
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexService.getShard(id)).thenReturn(indexShard);
+
+        final ShardId shardId = new ShardId(index, id);
+        when(indexShard.shardId()).thenReturn(shardId);
+
+        final SegmentReplicationTargetService mockTargetService = mock(SegmentReplicationTargetService.class);
+
+        final PublishCheckpointAction action = new PublishCheckpointAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            indicesService,
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet()),
+            mockTargetService
+        );
+
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(indexShard.shardId(), 1111, 11, 1, Codec.getDefault().getName());
+        final PublishCheckpointRequest request = new PublishCheckpointRequest(checkpoint);
+
+        action.shardOperationOnPrimary(request, indexShard, ActionTestUtils.assertNoFailureListener(result -> {
+            // we should forward the request containing the current publish checkpoint to the replica
+            assertThat(result.replicaRequest(), sameInstance(request));
+        }));
+    }
+
+    public void testPublishCheckpointActionOnReplica() {
+        final IndicesService indicesService = mock(IndicesService.class);
+
+        final Index index = new Index("index", "uuid");
+        final IndexService indexService = mock(IndexService.class);
+        when(indicesService.indexServiceSafe(index)).thenReturn(indexService);
+        final int id = randomIntBetween(0, 4);
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexService.getShard(id)).thenReturn(indexShard);
+
+        final ShardId shardId = new ShardId(index, id);
+        when(indexShard.shardId()).thenReturn(shardId);
+
+        final SegmentReplicationTargetService mockTargetService = mock(SegmentReplicationTargetService.class);
+
+        final PublishCheckpointAction action = new PublishCheckpointAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            indicesService,
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet()),
+            mockTargetService
+        );
+
+        final ReplicationCheckpoint checkpoint = new ReplicationCheckpoint(indexShard.shardId(), 1111, 11, 1, Codec.getDefault().getName());
+
+        final PublishCheckpointRequest request = new PublishCheckpointRequest(checkpoint);
+
+        final PlainActionFuture<TransportReplicationAction.ReplicaResult> listener = PlainActionFuture.newFuture();
+        action.shardOperationOnReplica(request, indexShard, listener);
+        final TransportReplicationAction.ReplicaResult result = listener.actionGet();
+
+        // onNewCheckpoint should be called on shard with checkpoint request
+        verify(mockTargetService, times(1)).onNewCheckpoint(checkpoint, indexShard);
+
+        // the result should indicate success
+        final AtomicBoolean success = new AtomicBoolean();
+        result.runPostReplicaActions(ActionListener.wrap(r -> success.set(true), e -> fail(e.toString())));
+        assertTrue(success.get());
+
+    }
+
+    public void testGetReplicationModeWithRemoteTranslog() {
+        final PublishCheckpointAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(true);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    public void testGetReplicationModeWithLocalTranslog() {
+        final PublishCheckpointAction action = createAction();
+        final IndexShard indexShard = mock(IndexShard.class);
+        when(indexShard.isRemoteTranslogEnabled()).thenReturn(false);
+        assertEquals(ReplicationMode.FULL_REPLICATION, action.getReplicationMode(indexShard));
+    }
+
+    private PublishCheckpointAction createAction() {
+        return new PublishCheckpointAction(
+            Settings.EMPTY,
+            transportService,
+            clusterService,
+            mock(IndicesService.class),
+            threadPool,
+            shardStateAction,
+            new ActionFilters(Collections.emptySet()),
+            mock(SegmentReplicationTargetService.class)
+        );
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/indices/replication/common/CopyStateTests.java b/server/src/test/java/org/opensearch/indices/replication/common/CopyStateTests.java
new file mode 100644
index 0000000000000..df180a8ab1007
--- /dev/null
+++ b/server/src/test/java/org/opensearch/indices/replication/common/CopyStateTests.java
@@ -0,0 +1,103 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication.common;
+
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.IndexFileNames;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.util.Version;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.env.Environment;
+import org.opensearch.index.codec.CodecService;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.test.IndexSettingsModule;
+
+import java.io.IOException;
+import java.util.Map;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class CopyStateTests extends IndexShardTestCase {
+
+    private static final long EXPECTED_LONG_VALUE = 1L;
+    private static final ShardId TEST_SHARD_ID = new ShardId("testIndex", "testUUID", 0);
+    private static final StoreFileMetadata SEGMENTS_FILE = new StoreFileMetadata(IndexFileNames.SEGMENTS, 1L, "0", Version.LATEST);
+    private static final StoreFileMetadata SEGMENT_FILE = new StoreFileMetadata("_0.si", 1L, "0", Version.LATEST);
+    private static final StoreFileMetadata PENDING_DELETE_FILE = new StoreFileMetadata("pendingDelete.del", 1L, "1", Version.LATEST);
+
+    private static final Store.MetadataSnapshot COMMIT_SNAPSHOT = new Store.MetadataSnapshot(
+        Map.of(SEGMENTS_FILE.name(), SEGMENTS_FILE, PENDING_DELETE_FILE.name(), PENDING_DELETE_FILE),
+        null,
+        0
+    );
+
+    private static final Store.MetadataSnapshot SI_SNAPSHOT = new Store.MetadataSnapshot(
+        Map.of(SEGMENT_FILE.name(), SEGMENT_FILE),
+        null,
+        0
+    );
+
+    public void testCopyStateCreation() throws IOException {
+        final IndexShard mockIndexShard = createMockIndexShard();
+        CopyState copyState = new CopyState(
+            ReplicationCheckpoint.empty(
+                mockIndexShard.shardId(),
+                new CodecService(null, mockIndexShard.indexSettings(), null).codec("default").getName()
+            ),
+            mockIndexShard
+        );
+        ReplicationCheckpoint checkpoint = copyState.getCheckpoint();
+        assertEquals(TEST_SHARD_ID, checkpoint.getShardId());
+        // version was never set so this should be zero
+        assertEquals(0, checkpoint.getSegmentInfosVersion());
+        assertEquals(EXPECTED_LONG_VALUE, checkpoint.getPrimaryTerm());
+    }
+
+    public static IndexShard createMockIndexShard() throws IOException {
+        IndexShard mockShard = mock(IndexShard.class);
+        when(mockShard.shardId()).thenReturn(TEST_SHARD_ID);
+        when(mockShard.getOperationPrimaryTerm()).thenReturn(EXPECTED_LONG_VALUE);
+        when(mockShard.getProcessedLocalCheckpoint()).thenReturn(EXPECTED_LONG_VALUE);
+
+        Store mockStore = mock(Store.class);
+        when(mockShard.store()).thenReturn(mockStore);
+
+        Settings nodeSettings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir()).build();
+        when(mockShard.indexSettings()).thenReturn(IndexSettingsModule.newIndexSettings("_na", nodeSettings));
+
+        SegmentInfos testSegmentInfos = new SegmentInfos(Version.LATEST.major);
+        ReplicationCheckpoint testCheckpoint = new ReplicationCheckpoint(
+            mockShard.shardId(),
+            mockShard.getOperationPrimaryTerm(),
+            0L,
+            0L,
+            Codec.getDefault().getName()
+        );
+        final Tuple<GatedCloseable<SegmentInfos>, ReplicationCheckpoint> gatedCloseableReplicationCheckpointTuple = new Tuple<>(
+            new GatedCloseable<>(testSegmentInfos, () -> {}),
+            testCheckpoint
+        );
+        when(mockShard.getLatestSegmentInfosAndCheckpoint()).thenReturn(gatedCloseableReplicationCheckpointTuple);
+        when(mockStore.getSegmentMetadataMap(testSegmentInfos)).thenReturn(SI_SNAPSHOT.asMap());
+
+        IndexCommit mockIndexCommit = mock(IndexCommit.class);
+        when(mockShard.acquireLastIndexCommit(false)).thenReturn(new GatedCloseable<>(mockIndexCommit, () -> {}));
+        when(mockStore.getMetadata(mockIndexCommit)).thenReturn(COMMIT_SNAPSHOT);
+        return mockShard;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/indices/settings/InternalOrPrivateSettingsPlugin.java b/server/src/test/java/org/opensearch/indices/settings/InternalOrPrivateSettingsPlugin.java
index a44dc66d6feac..b990e64bf0f18 100644
--- a/server/src/test/java/org/opensearch/indices/settings/InternalOrPrivateSettingsPlugin.java
+++ b/server/src/test/java/org/opensearch/indices/settings/InternalOrPrivateSettingsPlugin.java
@@ -32,14 +32,12 @@
 
 package org.opensearch.indices.settings;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.action.support.master.MasterNodeRequest;
-import org.opensearch.action.support.master.TransportMasterNodeAction;
+import org.opensearch.action.support.clustermanager.ClusterManagerNodeRequest;
+import org.opensearch.action.support.clustermanager.TransportClusterManagerNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -48,10 +46,12 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.threadpool.ThreadPool;
@@ -90,7 +90,7 @@ public UpdateInternalOrPrivateAction() {
             super(NAME, UpdateInternalOrPrivateAction.Response::new);
         }
 
-        public static class Request extends MasterNodeRequest<Request> {
+        public static class Request extends ClusterManagerNodeRequest<Request> {
 
             private String index;
             private String key;
@@ -139,7 +139,7 @@ public void writeTo(StreamOutput out) throws IOException {}
 
     }
 
-    public static class TransportUpdateInternalOrPrivateAction extends TransportMasterNodeAction<
+    public static class TransportUpdateInternalOrPrivateAction extends TransportClusterManagerNodeAction<
         UpdateInternalOrPrivateAction.Request,
         UpdateInternalOrPrivateAction.Response> {
 
@@ -173,7 +173,7 @@ protected UpdateInternalOrPrivateAction.Response read(StreamInput in) throws IOE
         }
 
         @Override
-        protected void masterOperation(
+        protected void clusterManagerOperation(
             final UpdateInternalOrPrivateAction.Request request,
             final ClusterState state,
             final ActionListener<UpdateInternalOrPrivateAction.Response> listener
diff --git a/server/src/test/java/org/opensearch/indices/store/IndicesStoreTests.java b/server/src/test/java/org/opensearch/indices/store/IndicesStoreTests.java
index a3130400719ad..40c5a631ce5d9 100644
--- a/server/src/test/java/org/opensearch/indices/store/IndicesStoreTests.java
+++ b/server/src/test/java/org/opensearch/indices/store/IndicesStoreTests.java
@@ -38,7 +38,7 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/ingest/CompoundProcessorTests.java b/server/src/test/java/org/opensearch/ingest/CompoundProcessorTests.java
index fb0c55fce28f1..76301acac0c19 100644
--- a/server/src/test/java/org/opensearch/ingest/CompoundProcessorTests.java
+++ b/server/src/test/java/org/opensearch/ingest/CompoundProcessorTests.java
@@ -33,6 +33,7 @@
 package org.opensearch.ingest;
 
 import org.opensearch.OpenSearchException;
+import org.opensearch.common.metrics.OperationStats;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
@@ -75,9 +76,9 @@ public void testEmpty() throws Exception {
     public void testSingleProcessor() throws Exception {
         LongSupplier relativeTimeProvider = mock(LongSupplier.class);
         when(relativeTimeProvider.getAsLong()).thenReturn(0L, TimeUnit.MILLISECONDS.toNanos(1));
-        TestProcessor processor = new TestProcessor(
-            ingestDocument -> { assertStats(0, ingestDocument.getFieldValue("compoundProcessor", CompoundProcessor.class), 1, 0, 0, 0); }
-        );
+        TestProcessor processor = new TestProcessor(ingestDocument -> {
+            assertStats(0, ingestDocument.getFieldValue("compoundProcessor", CompoundProcessor.class), 1, 0, 0, 0);
+        });
         CompoundProcessor compoundProcessor = new CompoundProcessor(relativeTimeProvider, processor);
         ingestDocument.setFieldValue("compoundProcessor", compoundProcessor); // ugly hack to assert current count = 1
         assertThat(compoundProcessor.getProcessors().size(), equalTo(1));
@@ -433,10 +434,10 @@ private void assertStats(CompoundProcessor compoundProcessor, long count, long f
     }
 
     private void assertStats(int processor, CompoundProcessor compoundProcessor, long current, long count, long failed, long time) {
-        IngestStats.Stats stats = compoundProcessor.getProcessorsWithMetrics().get(processor).v2().createStats();
-        assertThat(stats.getIngestCount(), equalTo(count));
-        assertThat(stats.getIngestCurrent(), equalTo(current));
-        assertThat(stats.getIngestFailedCount(), equalTo(failed));
-        assertThat(stats.getIngestTimeInMillis(), equalTo(time));
+        OperationStats stats = compoundProcessor.getProcessorsWithMetrics().get(processor).v2().createStats();
+        assertThat(stats.getCount(), equalTo(count));
+        assertThat(stats.getCurrent(), equalTo(current));
+        assertThat(stats.getFailedCount(), equalTo(failed));
+        assertThat(stats.getTotalTimeInMillis(), equalTo(time));
     }
 }
diff --git a/server/src/test/java/org/opensearch/ingest/ConditionalProcessorTests.java b/server/src/test/java/org/opensearch/ingest/ConditionalProcessorTests.java
index 2fc734c5abbf2..921ac10c02862 100644
--- a/server/src/test/java/org/opensearch/ingest/ConditionalProcessorTests.java
+++ b/server/src/test/java/org/opensearch/ingest/ConditionalProcessorTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.ingest;
 
+import org.opensearch.common.metrics.OperationStats;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.script.IngestConditionalScript;
 import org.opensearch.script.MockScriptEngine;
@@ -163,72 +164,11 @@ public void testActsOnImmutableData() throws Exception {
         assertMutatingCtxThrows(ctx -> ((List<Object>) ctx.get("listField")).remove("bar"));
     }
 
-    public void testTypeDeprecation() throws Exception {
-
-        ScriptService scriptService = new ScriptService(
-            Settings.builder().build(),
-            Collections.singletonMap(
-                Script.DEFAULT_SCRIPT_LANG,
-                new MockScriptEngine(Script.DEFAULT_SCRIPT_LANG, Collections.singletonMap(scriptName, ctx -> {
-                    ctx.get("_type");
-                    return true;
-                }), Collections.emptyMap())
-            ),
-            new HashMap<>(ScriptModule.CORE_CONTEXTS)
-        );
-
-        LongSupplier relativeTimeProvider = mock(LongSupplier.class);
-        when(relativeTimeProvider.getAsLong()).thenReturn(0L, TimeUnit.MILLISECONDS.toNanos(1), 0L, TimeUnit.MILLISECONDS.toNanos(2));
-        ConditionalProcessor processor = new ConditionalProcessor(
-            randomAlphaOfLength(10),
-            "description",
-            new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
-            scriptService,
-            new Processor() {
-                @Override
-                public IngestDocument execute(final IngestDocument ingestDocument) {
-                    return ingestDocument;
-                }
-
-                @Override
-                public String getType() {
-                    return null;
-                }
-
-                @Override
-                public String getTag() {
-                    return null;
-                }
-
-                @Override
-                public String getDescription() {
-                    return null;
-                }
-            },
-            relativeTimeProvider
-        );
-
-        IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random(), Collections.emptyMap());
-        processor.execute(ingestDocument, (result, e) -> {});
-        assertWarnings("[types removal] Looking up doc types [_type] in scripts is deprecated.");
-    }
-
     public void testPrecompiledError() {
-        ScriptService scriptService = MockScriptService.singleContext(
-            IngestConditionalScript.CONTEXT,
-            code -> {
-                throw new ScriptException(
-                    "bad script",
-                    new ParseException("error", 0),
-                    org.opensearch.common.collect.List.of(),
-                    "",
-                    "lang",
-                    null
-                );
-            },
-            org.opensearch.common.collect.Map.of()
-        );
-        Script script = new Script(ScriptType.INLINE, "lang", "foo", org.opensearch.common.collect.Map.of());
+        ScriptService scriptService = MockScriptService.singleContext(IngestConditionalScript.CONTEXT, code -> {
+            throw new ScriptException("bad script", new ParseException("error", 0), List.of(), "", "lang", null);
+        }, Map.of());
+        Script script = new Script(ScriptType.INLINE, "lang", "foo", Map.of());
         ScriptException e = expectThrows(ScriptException.class, () -> new ConditionalProcessor(null, null, script, scriptService, null));
         assertThat(e.getMessage(), equalTo("bad script"));
     }
@@ -236,17 +176,10 @@ public void testPrecompiledError() {
     public void testRuntimeCompileError() {
         AtomicBoolean fail = new AtomicBoolean(false);
         Map<String, StoredScriptSource> storedScripts = new HashMap<>();
-        storedScripts.put("foo", new StoredScriptSource("lang", "", org.opensearch.common.collect.Map.of()));
+        storedScripts.put("foo", new StoredScriptSource("lang", "", Map.of()));
         ScriptService scriptService = MockScriptService.singleContext(IngestConditionalScript.CONTEXT, code -> {
             if (fail.get()) {
-                throw new ScriptException(
-                    "bad script",
-                    new ParseException("error", 0),
-                    org.opensearch.common.collect.List.of(),
-                    "",
-                    "lang",
-                    null
-                );
+                throw new ScriptException("bad script", new ParseException("error", 0), List.of(), "", "lang", null);
             } else {
                 return params -> new IngestConditionalScript(params) {
                     @Override
@@ -256,12 +189,12 @@ public boolean execute(Map<String, Object> ctx) {
                 };
             }
         }, storedScripts);
-        Script script = new Script(ScriptType.STORED, null, "foo", org.opensearch.common.collect.Map.of());
+        Script script = new Script(ScriptType.STORED, null, "foo", Map.of());
         ConditionalProcessor processor = new ConditionalProcessor(null, null, script, scriptService, null);
         fail.set(true);
         // must change the script source or the cached version will be used
-        storedScripts.put("foo", new StoredScriptSource("lang", "changed", org.opensearch.common.collect.Map.of()));
-        IngestDocument ingestDoc = new IngestDocument(org.opensearch.common.collect.Map.of(), org.opensearch.common.collect.Map.of());
+        storedScripts.put("foo", new StoredScriptSource("lang", "changed", Map.of()));
+        IngestDocument ingestDoc = new IngestDocument(Map.of(), Map.of());
         processor.execute(ingestDoc, (doc, e) -> { assertThat(e.getMessage(), equalTo("bad script")); });
     }
 
@@ -274,11 +207,11 @@ public boolean execute(Map<String, Object> ctx) {
                     throw new IllegalArgumentException("runtime problem");
                 }
             },
-            org.opensearch.common.collect.Map.of()
+            Map.of()
         );
-        Script script = new Script(ScriptType.INLINE, "lang", "foo", org.opensearch.common.collect.Map.of());
+        Script script = new Script(ScriptType.INLINE, "lang", "foo", Map.of());
         ConditionalProcessor processor = new ConditionalProcessor(null, null, script, scriptService, null);
-        IngestDocument ingestDoc = new IngestDocument(org.opensearch.common.collect.Map.of(), org.opensearch.common.collect.Map.of());
+        IngestDocument ingestDoc = new IngestDocument(Map.of(), Map.of());
         processor.execute(ingestDoc, (doc, e) -> { assertThat(e.getMessage(), equalTo("runtime problem")); });
     }
 
@@ -318,10 +251,10 @@ private static void assertMutatingCtxThrows(Consumer<Map<String, Object>> mutati
     }
 
     private static void assertStats(ConditionalProcessor conditionalProcessor, long count, long failed, long time) {
-        IngestStats.Stats stats = conditionalProcessor.getMetric().createStats();
-        assertThat(stats.getIngestCount(), equalTo(count));
-        assertThat(stats.getIngestCurrent(), equalTo(0L));
-        assertThat(stats.getIngestFailedCount(), equalTo(failed));
-        assertThat(stats.getIngestTimeInMillis(), greaterThanOrEqualTo(time));
+        OperationStats stats = conditionalProcessor.getMetric().createStats();
+        assertThat(stats.getCount(), equalTo(count));
+        assertThat(stats.getCurrent(), equalTo(0L));
+        assertThat(stats.getFailedCount(), equalTo(failed));
+        assertThat(stats.getTotalTimeInMillis(), greaterThanOrEqualTo(time));
     }
 }
diff --git a/server/src/test/java/org/opensearch/ingest/ConfigurationUtilsTests.java b/server/src/test/java/org/opensearch/ingest/ConfigurationUtilsTests.java
index cf67c8af139fb..e18e5887c949e 100644
--- a/server/src/test/java/org/opensearch/ingest/ConfigurationUtilsTests.java
+++ b/server/src/test/java/org/opensearch/ingest/ConfigurationUtilsTests.java
@@ -179,6 +179,16 @@ public void testReadProcessors() throws Exception {
         assertThat(e2.getMetadata("opensearch.processor_tag"), equalTo(Collections.singletonList("my_second_unknown")));
         assertThat(e2.getMetadata("opensearch.processor_type"), equalTo(Collections.singletonList("second_unknown_processor")));
         assertThat(e2.getMetadata("opensearch.property_name"), is(nullValue()));
+
+        // test null config
+        List<Map<String, Object>> config3 = new ArrayList<>();
+        config3.add(Collections.singletonMap("null_processor", null));
+
+        OpenSearchParseException ex = expectThrows(
+            OpenSearchParseException.class,
+            () -> ConfigurationUtils.readProcessorConfigs(config3, scriptService, registry)
+        );
+        assertEquals(ex.getMessage(), "the config of processor [null_processor] cannot be null");
     }
 
     public void testReadProcessorNullDescription() throws Exception {
@@ -235,6 +245,12 @@ public void testReadProcessorFromObjectOrMap() throws Exception {
             () -> ConfigurationUtils.readProcessor(registry, scriptService, "unknown_processor", invalidConfig)
         );
         assertThat(ex.getMessage(), equalTo("property isn't a map, but of type [" + invalidConfig.getClass().getName() + "]"));
+
+        ex = expectThrows(
+            OpenSearchParseException.class,
+            () -> ConfigurationUtils.readProcessor(registry, scriptService, "null_processor", null)
+        );
+        assertEquals(ex.getMessage(), "expect the config of processor [null_processor] to be map, but is null");
     }
 
     public void testNoScriptCompilation() {
diff --git a/server/src/test/java/org/opensearch/ingest/IngestDocumentTests.java b/server/src/test/java/org/opensearch/ingest/IngestDocumentTests.java
index a6ea02a5423c4..8358dadf9cc3a 100644
--- a/server/src/test/java/org/opensearch/ingest/IngestDocumentTests.java
+++ b/server/src/test/java/org/opensearch/ingest/IngestDocumentTests.java
@@ -471,7 +471,7 @@ public void testListAppendFieldValueWithDuplicate() {
         @SuppressWarnings("unchecked")
         List<Object> list = (List<Object>) object;
         assertThat(list.size(), equalTo(3));
-        assertThat(list, equalTo(org.opensearch.common.collect.List.of("foo", "bar", "baz")));
+        assertThat(list, equalTo(List.of("foo", "bar", "baz")));
     }
 
     public void testListAppendFieldValueWithoutDuplicate() {
@@ -481,7 +481,7 @@ public void testListAppendFieldValueWithoutDuplicate() {
         @SuppressWarnings("unchecked")
         List<Object> list = (List<Object>) object;
         assertThat(list.size(), equalTo(4));
-        assertThat(list, equalTo(org.opensearch.common.collect.List.of("foo", "bar", "baz", "foo2")));
+        assertThat(list, equalTo(List.of("foo", "bar", "baz", "foo2")));
     }
 
     public void testListAppendFieldValues() {
@@ -499,7 +499,7 @@ public void testListAppendFieldValues() {
     }
 
     public void testListAppendFieldValuesWithoutDuplicates() {
-        ingestDocument.appendFieldValue("list2", org.opensearch.common.collect.List.of("foo", "bar", "baz", "foo2"), false);
+        ingestDocument.appendFieldValue("list2", List.of("foo", "bar", "baz", "foo2"), false);
         Object object = ingestDocument.getSourceAndMetadata().get("list2");
         assertThat(object, instanceOf(List.class));
         @SuppressWarnings("unchecked")
diff --git a/server/src/test/java/org/opensearch/ingest/IngestMetadataTests.java b/server/src/test/java/org/opensearch/ingest/IngestMetadataTests.java
index 5ab2209f750e8..77444e43af910 100644
--- a/server/src/test/java/org/opensearch/ingest/IngestMetadataTests.java
+++ b/server/src/test/java/org/opensearch/ingest/IngestMetadataTests.java
@@ -34,13 +34,13 @@
 
 import org.opensearch.cluster.DiffableUtils;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -57,18 +57,18 @@ public void testFromXContent() throws IOException {
         PipelineConfiguration pipeline = new PipelineConfiguration(
             "1",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         PipelineConfiguration pipeline2 = new PipelineConfiguration(
             "2",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field1\", \"value\": \"_value1\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         Map<String, PipelineConfiguration> map = new HashMap<>();
         map.put(pipeline.getId(), pipeline);
         map.put(pipeline2.getId(), pipeline2);
         IngestMetadata ingestMetadata = new IngestMetadata(map);
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         builder.prettyPrint();
         builder.startObject();
         ingestMetadata.toXContent(builder, ToXContent.EMPTY_PARAMS);
@@ -90,14 +90,14 @@ public void testDiff() throws Exception {
         BytesReference pipelineConfig = new BytesArray("{}");
 
         Map<String, PipelineConfiguration> pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, XContentType.JSON));
-        pipelines.put("2", new PipelineConfiguration("2", pipelineConfig, XContentType.JSON));
+        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, MediaTypeRegistry.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", pipelineConfig, MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata1 = new IngestMetadata(pipelines);
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, XContentType.JSON));
-        pipelines.put("3", new PipelineConfiguration("3", pipelineConfig, XContentType.JSON));
-        pipelines.put("4", new PipelineConfiguration("4", pipelineConfig, XContentType.JSON));
+        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, MediaTypeRegistry.JSON));
+        pipelines.put("3", new PipelineConfiguration("3", pipelineConfig, MediaTypeRegistry.JSON));
+        pipelines.put("4", new PipelineConfiguration("4", pipelineConfig, MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata2 = new IngestMetadata(pipelines);
 
         IngestMetadata.IngestMetadataDiff diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata2.diff(ingestMetadata1);
@@ -110,13 +110,13 @@ public void testDiff() throws Exception {
         IngestMetadata endResult = (IngestMetadata) diff.apply(ingestMetadata2);
         assertThat(endResult, not(equalTo(ingestMetadata1)));
         assertThat(endResult.getPipelines().size(), equalTo(3));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
-        assertThat(endResult.getPipelines().get("3"), equalTo(new PipelineConfiguration("3", pipelineConfig, XContentType.JSON)));
-        assertThat(endResult.getPipelines().get("4"), equalTo(new PipelineConfiguration("4", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, MediaTypeRegistry.JSON)));
+        assertThat(endResult.getPipelines().get("3"), equalTo(new PipelineConfiguration("3", pipelineConfig, MediaTypeRegistry.JSON)));
+        assertThat(endResult.getPipelines().get("4"), equalTo(new PipelineConfiguration("4", pipelineConfig, MediaTypeRegistry.JSON)));
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), XContentType.JSON));
-        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{}"), XContentType.JSON));
+        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), MediaTypeRegistry.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{}"), MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata3 = new IngestMetadata(pipelines);
 
         diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata3.diff(ingestMetadata1);
@@ -126,12 +126,12 @@ public void testDiff() throws Exception {
         endResult = (IngestMetadata) diff.apply(ingestMetadata3);
         assertThat(endResult, equalTo(ingestMetadata1));
         assertThat(endResult.getPipelines().size(), equalTo(2));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
-        assertThat(endResult.getPipelines().get("2"), equalTo(new PipelineConfiguration("2", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, MediaTypeRegistry.JSON)));
+        assertThat(endResult.getPipelines().get("2"), equalTo(new PipelineConfiguration("2", pipelineConfig, MediaTypeRegistry.JSON)));
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), XContentType.JSON));
-        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), XContentType.JSON));
+        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), MediaTypeRegistry.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata4 = new IngestMetadata(pipelines);
 
         diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata4.diff(ingestMetadata1);
@@ -141,10 +141,10 @@ public void testDiff() throws Exception {
         endResult = (IngestMetadata) diff.apply(ingestMetadata4);
         assertThat(endResult, not(equalTo(ingestMetadata1)));
         assertThat(endResult.getPipelines().size(), equalTo(2));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, MediaTypeRegistry.JSON)));
         assertThat(
             endResult.getPipelines().get("2"),
-            equalTo(new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), XContentType.JSON))
+            equalTo(new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), MediaTypeRegistry.JSON))
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java b/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
index fcd15e85979f7..1dfd41e96817e 100644
--- a/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
+++ b/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.Version;
@@ -57,12 +56,15 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.metrics.OperationStats;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.cbor.CborXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.plugins.IngestPlugin;
@@ -71,13 +73,11 @@
 import org.opensearch.script.ScriptModule;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.ScriptType;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.threadpool.ThreadPool.Names;
 import org.junit.Before;
-import org.mockito.ArgumentMatcher;
-import org.mockito.invocation.InvocationOnMock;
 
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
@@ -96,6 +96,9 @@
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
 
+import org.mockito.ArgumentMatcher;
+import org.mockito.invocation.InvocationOnMock;
+
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static org.hamcrest.Matchers.equalTo;
@@ -109,9 +112,9 @@
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.argThat;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
@@ -220,7 +223,7 @@ public void testUpdatePipelines() {
         PipelineConfiguration pipeline = new PipelineConfiguration(
             "_id",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         IngestMetadata ingestMetadata = new IngestMetadata(Collections.singletonMap("_id", pipeline));
         clusterState = ClusterState.builder(clusterState)
@@ -238,7 +241,7 @@ public void testInnerUpdatePipelines() {
         IngestService ingestService = createWithProcessors();
         assertThat(ingestService.pipelines().size(), is(0));
 
-        PipelineConfiguration pipeline1 = new PipelineConfiguration("_id1", new BytesArray("{\"processors\": []}"), XContentType.JSON);
+        PipelineConfiguration pipeline1 = new PipelineConfiguration("_id1", new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON);
         IngestMetadata ingestMetadata = new IngestMetadata(mapOf("_id1", pipeline1));
 
         ingestService.innerUpdatePipelines(ingestMetadata);
@@ -246,7 +249,7 @@ public void testInnerUpdatePipelines() {
         assertThat(ingestService.pipelines().get("_id1").pipeline.getId(), equalTo("_id1"));
         assertThat(ingestService.pipelines().get("_id1").pipeline.getProcessors().size(), equalTo(0));
 
-        PipelineConfiguration pipeline2 = new PipelineConfiguration("_id2", new BytesArray("{\"processors\": []}"), XContentType.JSON);
+        PipelineConfiguration pipeline2 = new PipelineConfiguration("_id2", new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON);
         ingestMetadata = new IngestMetadata(mapOf("_id1", pipeline1, "_id2", pipeline2));
 
         ingestService.innerUpdatePipelines(ingestMetadata);
@@ -256,7 +259,7 @@ public void testInnerUpdatePipelines() {
         assertThat(ingestService.pipelines().get("_id2").pipeline.getId(), equalTo("_id2"));
         assertThat(ingestService.pipelines().get("_id2").pipeline.getProcessors().size(), equalTo(0));
 
-        PipelineConfiguration pipeline3 = new PipelineConfiguration("_id3", new BytesArray("{\"processors\": []}"), XContentType.JSON);
+        PipelineConfiguration pipeline3 = new PipelineConfiguration("_id3", new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON);
         ingestMetadata = new IngestMetadata(mapOf("_id1", pipeline1, "_id2", pipeline2, "_id3", pipeline3));
 
         ingestService.innerUpdatePipelines(ingestMetadata);
@@ -280,7 +283,7 @@ public void testInnerUpdatePipelines() {
         pipeline3 = new PipelineConfiguration(
             "_id3",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ingestMetadata = new IngestMetadata(mapOf("_id1", pipeline1, "_id3", pipeline3));
 
@@ -322,7 +325,7 @@ public void testDelete() {
         PipelineConfiguration config = new PipelineConfiguration(
             "_id",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         IngestMetadata ingestMetadata = new IngestMetadata(Collections.singletonMap("_id", config));
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
@@ -354,7 +357,7 @@ public void testValidateNoIngestInfo() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         Exception e = expectThrows(IllegalStateException.class, () -> ingestService.validatePipeline(emptyMap(), putRequest));
         assertEquals("Ingest info is empty", e.getMessage());
@@ -383,7 +386,7 @@ public void testGetProcessorsInPipeline() throws Exception {
                 "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\", \"tag\": \"tag1\"}},"
                     + "{\"remove\" : {\"field\": \"_field\", \"tag\": \"tag2\"}}]}"
             ),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -449,7 +452,7 @@ public void testGetProcessorsInPipelineComplexConditional() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             id,
             new BytesArray("{\"processors\": [{\"complexSet\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -475,7 +478,7 @@ public void testCrud() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             id,
             new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -503,7 +506,7 @@ public void testPut() {
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
 
         // add a new pipeline:
-        PutPipelineRequest putRequest = new PutPipelineRequest(id, new BytesArray("{\"processors\": []}"), XContentType.JSON);
+        PutPipelineRequest putRequest = new PutPipelineRequest(id, new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON);
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
         ingestService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
@@ -517,7 +520,7 @@ public void testPut() {
         putRequest = new PutPipelineRequest(
             id,
             new BytesArray("{\"processors\": [], \"description\": \"_description\"}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -539,7 +542,7 @@ public void testPutWithErrorResponse() throws IllegalAccessException {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             id,
             new BytesArray("{\"description\": \"empty processors\"}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -571,9 +574,9 @@ public void testDeleteUsingWildcard() {
         IngestService ingestService = createWithProcessors();
         HashMap<String, PipelineConfiguration> pipelines = new HashMap<>();
         BytesArray definition = new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}");
-        pipelines.put("p1", new PipelineConfiguration("p1", definition, XContentType.JSON));
-        pipelines.put("p2", new PipelineConfiguration("p2", definition, XContentType.JSON));
-        pipelines.put("q1", new PipelineConfiguration("q1", definition, XContentType.JSON));
+        pipelines.put("p1", new PipelineConfiguration("p1", definition, MediaTypeRegistry.JSON));
+        pipelines.put("p2", new PipelineConfiguration("p2", definition, MediaTypeRegistry.JSON));
+        pipelines.put("q1", new PipelineConfiguration("q1", definition, MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata = new IngestMetadata(pipelines);
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
         ClusterState previousClusterState = clusterState;
@@ -619,7 +622,7 @@ public void testDeleteWithExistingUnmatchedPipelines() {
         IngestService ingestService = createWithProcessors();
         HashMap<String, PipelineConfiguration> pipelines = new HashMap<>();
         BytesArray definition = new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}");
-        pipelines.put("p1", new PipelineConfiguration("p1", definition, XContentType.JSON));
+        pipelines.put("p1", new PipelineConfiguration("p1", definition, MediaTypeRegistry.JSON));
         IngestMetadata ingestMetadata = new IngestMetadata(pipelines);
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
         ClusterState previousClusterState = clusterState;
@@ -640,8 +643,8 @@ public void testDeleteWithExistingUnmatchedPipelines() {
 
     public void testGetPipelines() {
         Map<String, PipelineConfiguration> configs = new HashMap<>();
-        configs.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{\"processors\": []}"), XContentType.JSON));
-        configs.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{\"processors\": []}"), XContentType.JSON));
+        configs.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON));
+        configs.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{\"processors\": []}"), MediaTypeRegistry.JSON));
 
         assertThat(IngestService.innerGetPipelines(null, "_id1").isEmpty(), is(true));
 
@@ -683,7 +686,7 @@ public void testValidate() throws Exception {
                 "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\", \"tag\": \"tag1\"}},"
                     + "{\"remove\" : {\"field\": \"_field\", \"tag\": \"tag2\"}}]}"
             ),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
 
         DiscoveryNode node1 = new DiscoveryNode("_node_id1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
@@ -723,7 +726,7 @@ public String getType() {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             id,
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -769,7 +772,7 @@ public void testExecuteBulkPipelineDoesNotExist() {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -816,7 +819,7 @@ public void testExecuteSuccess() {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -847,7 +850,7 @@ public void testExecuteEmptyPipeline() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [], \"description\": \"_description\"}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -881,7 +884,7 @@ public void testExecutePropagateAllMetadataUpdates() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -948,7 +951,7 @@ public void testExecuteFailure() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1008,7 +1011,7 @@ public void testExecuteSuccessWithOnFailure() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1051,7 +1054,7 @@ public void testExecuteFailureWithNestedOnFailure() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1122,7 +1125,7 @@ public void testBulkRequestExecutionWithFailures() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1180,7 +1183,7 @@ public void testBulkRequestExecution() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"mock\": {}}], \"description\": \"_description\"}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
         ClusterState previousClusterState = clusterState;
@@ -1240,13 +1243,13 @@ public void testStats() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id1",
             new BytesArray("{\"processors\": [{\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
         ingestService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
-        putRequest = new PutPipelineRequest("_id2", new BytesArray("{\"processors\": [{\"mock\" : {}}]}"), XContentType.JSON);
+        putRequest = new PutPipelineRequest("_id2", new BytesArray("{\"processors\": [{\"mock\" : {}}]}"), MediaTypeRegistry.JSON);
         previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
         ingestService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
@@ -1306,7 +1309,7 @@ public void testStats() throws Exception {
         putRequest = new PutPipelineRequest(
             "_id1",
             new BytesArray("{\"processors\": [{\"mock\" : {}}, {\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -1339,7 +1342,7 @@ public void testStats() throws Exception {
         putRequest = new PutPipelineRequest(
             "_id1",
             new BytesArray("{\"processors\": [{\"failure-mock\" : { \"on_failure\": [{\"mock\" : {}}]}}, {\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         previousClusterState = clusterState;
         clusterState = IngestService.innerPut(putRequest, clusterState);
@@ -1417,7 +1420,7 @@ public String getDescription() {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"drop\" : {}}, {\"mock\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1490,7 +1493,7 @@ public Map<String, Processor.Factory> getProcessors(Processor.Parameters paramet
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"test\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
         ClusterState previousClusterState = clusterState;
@@ -1513,7 +1516,7 @@ public void testCBORParsing() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest(
             "_id",
             new BytesArray("{\"processors\": [{\"foo\" : {}}]}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
         clusterState = IngestService.innerPut(putRequest, clusterState);
         ingestService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
@@ -1739,14 +1742,14 @@ private void assertPipelineStats(List<IngestStats.PipelineStat> pipelineStats, S
         assertStats(getPipelineStats(pipelineStats, pipelineId), count, failed, time);
     }
 
-    private void assertStats(IngestStats.Stats stats, long count, long failed, long time) {
-        assertThat(stats.getIngestCount(), equalTo(count));
-        assertThat(stats.getIngestCurrent(), equalTo(0L));
-        assertThat(stats.getIngestFailedCount(), equalTo(failed));
-        assertThat(stats.getIngestTimeInMillis(), greaterThanOrEqualTo(time));
+    private void assertStats(OperationStats stats, long count, long failed, long time) {
+        assertThat(stats.getCount(), equalTo(count));
+        assertThat(stats.getCurrent(), equalTo(0L));
+        assertThat(stats.getFailedCount(), equalTo(failed));
+        assertThat(stats.getTotalTimeInMillis(), greaterThanOrEqualTo(time));
     }
 
-    private IngestStats.Stats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
+    private OperationStats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
         return pipelineStats.stream().filter(p1 -> p1.getPipelineId().equals(id)).findFirst().map(p2 -> p2.getStats()).orElse(null);
     }
 }
diff --git a/server/src/test/java/org/opensearch/ingest/IngestStatsTests.java b/server/src/test/java/org/opensearch/ingest/IngestStatsTests.java
index 0486c9f29f86e..b8e26da726a2b 100644
--- a/server/src/test/java/org/opensearch/ingest/IngestStatsTests.java
+++ b/server/src/test/java/org/opensearch/ingest/IngestStatsTests.java
@@ -35,7 +35,8 @@
 import org.opensearch.LegacyESVersion;
 import org.opensearch.common.collect.MapBuilder;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
@@ -50,7 +51,7 @@
 public class IngestStatsTests extends OpenSearchTestCase {
 
     public void testSerialization() throws IOException {
-        IngestStats.Stats totalStats = new IngestStats.Stats(50, 100, 200, 300);
+        OperationStats totalStats = new OperationStats(50, 100, 200, 300);
         List<IngestStats.PipelineStat> pipelineStats = createPipelineStats();
         Map<String, List<IngestStats.ProcessorStat>> processorStats = createProcessorStats(pipelineStats);
         IngestStats ingestStats = new IngestStats(totalStats, pipelineStats, processorStats);
@@ -59,7 +60,7 @@ public void testSerialization() throws IOException {
     }
 
     public void testBWCIngestProcessorTypeStats() throws IOException {
-        IngestStats.Stats totalStats = new IngestStats.Stats(50, 100, 200, 300);
+        OperationStats totalStats = new OperationStats(50, 100, 200, 300);
         List<IngestStats.PipelineStat> pipelineStats = createPipelineStats();
         Map<String, List<IngestStats.ProcessorStat>> processorStats = createProcessorStats(pipelineStats);
         IngestStats expectedIngestStats = new IngestStats(totalStats, pipelineStats, processorStats);
@@ -76,20 +77,20 @@ public void testBWCIngestProcessorTypeStats() throws IOException {
     }
 
     private List<IngestStats.PipelineStat> createPipelineStats() {
-        IngestStats.PipelineStat pipeline1Stats = new IngestStats.PipelineStat("pipeline1", new IngestStats.Stats(3, 3, 3, 3));
-        IngestStats.PipelineStat pipeline2Stats = new IngestStats.PipelineStat("pipeline2", new IngestStats.Stats(47, 97, 197, 297));
-        IngestStats.PipelineStat pipeline3Stats = new IngestStats.PipelineStat("pipeline3", new IngestStats.Stats(0, 0, 0, 0));
+        IngestStats.PipelineStat pipeline1Stats = new IngestStats.PipelineStat("pipeline1", new OperationStats(3, 3, 3, 3));
+        IngestStats.PipelineStat pipeline2Stats = new IngestStats.PipelineStat("pipeline2", new OperationStats(47, 97, 197, 297));
+        IngestStats.PipelineStat pipeline3Stats = new IngestStats.PipelineStat("pipeline3", new OperationStats(0, 0, 0, 0));
         return Stream.of(pipeline1Stats, pipeline2Stats, pipeline3Stats).collect(Collectors.toList());
     }
 
     private Map<String, List<IngestStats.ProcessorStat>> createProcessorStats(List<IngestStats.PipelineStat> pipelineStats) {
         assert (pipelineStats.size() >= 2);
-        IngestStats.ProcessorStat processor1Stat = new IngestStats.ProcessorStat("processor1", "type", new IngestStats.Stats(1, 1, 1, 1));
-        IngestStats.ProcessorStat processor2Stat = new IngestStats.ProcessorStat("processor2", "type", new IngestStats.Stats(2, 2, 2, 2));
+        IngestStats.ProcessorStat processor1Stat = new IngestStats.ProcessorStat("processor1", "type", new OperationStats(1, 1, 1, 1));
+        IngestStats.ProcessorStat processor2Stat = new IngestStats.ProcessorStat("processor2", "type", new OperationStats(2, 2, 2, 2));
         IngestStats.ProcessorStat processor3Stat = new IngestStats.ProcessorStat(
             "processor3",
             "type",
-            new IngestStats.Stats(47, 97, 197, 297)
+            new OperationStats(47, 97, 197, 297)
         );
         // pipeline1 -> processor1,processor2; pipeline2 -> processor3
         return MapBuilder.<String, List<IngestStats.ProcessorStat>>newMapBuilder()
@@ -151,14 +152,14 @@ private void assertIngestStats(
 
     }
 
-    private void assertStats(IngestStats.Stats fromObject, IngestStats.Stats fromStream) {
-        assertEquals(fromObject.getIngestCount(), fromStream.getIngestCount());
-        assertEquals(fromObject.getIngestFailedCount(), fromStream.getIngestFailedCount());
-        assertEquals(fromObject.getIngestTimeInMillis(), fromStream.getIngestTimeInMillis());
-        assertEquals(fromObject.getIngestCurrent(), fromStream.getIngestCurrent());
+    private void assertStats(OperationStats fromObject, OperationStats fromStream) {
+        assertEquals(fromObject.getCount(), fromStream.getCount());
+        assertEquals(fromObject.getFailedCount(), fromStream.getFailedCount());
+        assertEquals(fromObject.getTotalTimeInMillis(), fromStream.getTotalTimeInMillis());
+        assertEquals(fromObject.getCurrent(), fromStream.getCurrent());
     }
 
-    private IngestStats.Stats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
+    private OperationStats getPipelineStats(List<IngestStats.PipelineStat> pipelineStats, String id) {
         return pipelineStats.stream().filter(p1 -> p1.getPipelineId().equals(id)).findFirst().map(p2 -> p2.getStats()).orElse(null);
     }
 }
diff --git a/server/src/test/java/org/opensearch/ingest/PipelineConfigurationTests.java b/server/src/test/java/org/opensearch/ingest/PipelineConfigurationTests.java
index 62b6d7ad2f37f..7bcb29addce78 100644
--- a/server/src/test/java/org/opensearch/ingest/PipelineConfigurationTests.java
+++ b/server/src/test/java/org/opensearch/ingest/PipelineConfigurationTests.java
@@ -32,18 +32,19 @@
 
 package org.opensearch.ingest;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
@@ -56,15 +57,15 @@ public void testSerialization() throws IOException {
         PipelineConfiguration configuration = new PipelineConfiguration(
             "1",
             new BytesArray("{}".getBytes(StandardCharsets.UTF_8)),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         );
-        assertEquals(XContentType.JSON, configuration.getXContentType());
+        assertEquals(MediaTypeRegistry.JSON, configuration.getMediaType());
 
         BytesStreamOutput out = new BytesStreamOutput();
         configuration.writeTo(out);
         StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes);
         PipelineConfiguration serialized = PipelineConfiguration.readFrom(in);
-        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals(MediaTypeRegistry.JSON, serialized.getMediaType());
         assertEquals("{}", serialized.getConfig().utf8ToString());
     }
 
@@ -73,7 +74,7 @@ public void testParser() throws IOException {
         XContentType xContentType = randomFrom(XContentType.values());
         final BytesReference bytes;
         try (XContentBuilder builder = XContentBuilder.builder(xContentType.xContent())) {
-            new PipelineConfiguration("1", new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON).toXContent(
+            new PipelineConfiguration("1", new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), MediaTypeRegistry.JSON).toXContent(
                 builder,
                 ToXContent.EMPTY_PARAMS
             );
@@ -83,8 +84,8 @@ public void testParser() throws IOException {
         XContentParser xContentParser = xContentType.xContent()
             .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, bytes.streamInput());
         PipelineConfiguration parsed = parser.parse(xContentParser, null);
-        assertEquals(xContentType, parsed.getXContentType());
-        assertEquals("{}", XContentHelper.convertToJson(parsed.getConfig(), false, parsed.getXContentType()));
+        assertEquals(xContentType, parsed.getMediaType());
+        assertEquals("{}", XContentHelper.convertToJson(parsed.getConfig(), false, parsed.getMediaType()));
         assertEquals("1", parsed.getId());
     }
 
@@ -96,7 +97,7 @@ protected PipelineConfiguration createTestInstance() {
         } else {
             config = new BytesArray("{\"foo\": \"bar\"}".getBytes(StandardCharsets.UTF_8));
         }
-        return new PipelineConfiguration(randomAlphaOfLength(4), config, XContentType.JSON);
+        return new PipelineConfiguration(randomAlphaOfLength(4), config, MediaTypeRegistry.JSON);
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/ingest/PipelineProcessorTests.java b/server/src/test/java/org/opensearch/ingest/PipelineProcessorTests.java
index 86e4dd261d408..3708b5bc32955 100644
--- a/server/src/test/java/org/opensearch/ingest/PipelineProcessorTests.java
+++ b/server/src/test/java/org/opensearch/ingest/PipelineProcessorTests.java
@@ -32,6 +32,7 @@
 package org.opensearch.ingest;
 
 import org.opensearch.OpenSearchException;
+import org.opensearch.common.metrics.OperationStats;
 import org.opensearch.script.ScriptService;
 import org.opensearch.script.TemplateScript;
 import org.opensearch.test.OpenSearchTestCase;
@@ -172,25 +173,16 @@ public void testPipelineProcessorWithPipelineChain() throws Exception {
             pipeline2Id,
             null,
             null,
-            new CompoundProcessor(
-                true,
-                Arrays.asList(
-                    new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
-                    pipeline2Processor
-                ),
-                Collections.emptyList()
-            ),
+            new CompoundProcessor(true, Arrays.asList(new TestProcessor(ingestDocument -> {
+                ingestDocument.setFieldValue(key1, randomInt());
+            }), pipeline2Processor), Collections.emptyList()),
             relativeTimeProvider
         );
         relativeTimeProvider = mock(LongSupplier.class);
         when(relativeTimeProvider.getAsLong()).thenReturn(0L, TimeUnit.MILLISECONDS.toNanos(2));
-        Pipeline pipeline3 = new Pipeline(
-            pipeline3Id,
-            null,
-            null,
-            new CompoundProcessor(new TestProcessor(ingestDocument -> { throw new RuntimeException("error"); })),
-            relativeTimeProvider
-        );
+        Pipeline pipeline3 = new Pipeline(pipeline3Id, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            throw new RuntimeException("error");
+        })), relativeTimeProvider);
         when(ingestService.getPipeline(pipeline1Id)).thenReturn(pipeline1);
         when(ingestService.getPipeline(pipeline2Id)).thenReturn(pipeline2);
         when(ingestService.getPipeline(pipeline3Id)).thenReturn(pipeline3);
@@ -201,29 +193,29 @@ public void testPipelineProcessorWithPipelineChain() throws Exception {
         assertNotNull(ingestDocument.getSourceAndMetadata().get(key1));
 
         // check the stats
-        IngestStats.Stats pipeline1Stats = pipeline1.getMetrics().createStats();
-        IngestStats.Stats pipeline2Stats = pipeline2.getMetrics().createStats();
-        IngestStats.Stats pipeline3Stats = pipeline3.getMetrics().createStats();
+        OperationStats pipeline1Stats = pipeline1.getMetrics().createStats();
+        OperationStats pipeline2Stats = pipeline2.getMetrics().createStats();
+        OperationStats pipeline3Stats = pipeline3.getMetrics().createStats();
 
         // current
-        assertThat(pipeline1Stats.getIngestCurrent(), equalTo(0L));
-        assertThat(pipeline2Stats.getIngestCurrent(), equalTo(0L));
-        assertThat(pipeline3Stats.getIngestCurrent(), equalTo(0L));
+        assertThat(pipeline1Stats.getCurrent(), equalTo(0L));
+        assertThat(pipeline2Stats.getCurrent(), equalTo(0L));
+        assertThat(pipeline3Stats.getCurrent(), equalTo(0L));
 
         // count
-        assertThat(pipeline1Stats.getIngestCount(), equalTo(1L));
-        assertThat(pipeline2Stats.getIngestCount(), equalTo(1L));
-        assertThat(pipeline3Stats.getIngestCount(), equalTo(1L));
+        assertThat(pipeline1Stats.getCount(), equalTo(1L));
+        assertThat(pipeline2Stats.getCount(), equalTo(1L));
+        assertThat(pipeline3Stats.getCount(), equalTo(1L));
 
         // time
-        assertThat(pipeline1Stats.getIngestTimeInMillis(), equalTo(0L));
-        assertThat(pipeline2Stats.getIngestTimeInMillis(), equalTo(3L));
-        assertThat(pipeline3Stats.getIngestTimeInMillis(), equalTo(2L));
+        assertThat(pipeline1Stats.getTotalTimeInMillis(), equalTo(0L));
+        assertThat(pipeline2Stats.getTotalTimeInMillis(), equalTo(3L));
+        assertThat(pipeline3Stats.getTotalTimeInMillis(), equalTo(2L));
 
         // failure
-        assertThat(pipeline1Stats.getIngestFailedCount(), equalTo(0L));
-        assertThat(pipeline2Stats.getIngestFailedCount(), equalTo(0L));
-        assertThat(pipeline3Stats.getIngestFailedCount(), equalTo(1L));
+        assertThat(pipeline1Stats.getFailedCount(), equalTo(0L));
+        assertThat(pipeline2Stats.getFailedCount(), equalTo(0L));
+        assertThat(pipeline3Stats.getFailedCount(), equalTo(1L));
     }
 
     public void testIngestPipelineMetadata() {
diff --git a/server/src/test/java/org/opensearch/ingest/TrackingResultProcessorTests.java b/server/src/test/java/org/opensearch/ingest/TrackingResultProcessorTests.java
index 343b82e7c034b..af18727336960 100644
--- a/server/src/test/java/org/opensearch/ingest/TrackingResultProcessorTests.java
+++ b/server/src/test/java/org/opensearch/ingest/TrackingResultProcessorTests.java
@@ -41,7 +41,6 @@
 import org.opensearch.script.ScriptType;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
-import org.mockito.Mockito;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -50,6 +49,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.mockito.Mockito;
+
 import static org.opensearch.ingest.CompoundProcessor.ON_FAILURE_MESSAGE_FIELD;
 import static org.opensearch.ingest.CompoundProcessor.ON_FAILURE_PROCESSOR_TAG_FIELD;
 import static org.opensearch.ingest.CompoundProcessor.ON_FAILURE_PROCESSOR_TYPE_FIELD;
@@ -280,14 +281,17 @@ public void testActualCompoundProcessorWithFalseConditional() throws Exception {
             new HashMap<>(ScriptModule.CORE_CONTEXTS)
         );
 
-        CompoundProcessor compoundProcessor = new CompoundProcessor(
-            new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
+        CompoundProcessor compoundProcessor = new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        }),
             new ConditionalProcessor(
                 randomAlphaOfLength(10),
                 null,
                 new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
                 scriptService,
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); })
+                new TestProcessor(ingestDocument -> {
+                    ingestDocument.setFieldValue(key2, randomInt());
+                })
             ),
             new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
         );
@@ -331,16 +335,11 @@ public void testActualPipelineProcessor() throws Exception {
         String key2 = randomAlphaOfLength(10);
         String key3 = randomAlphaOfLength(10);
 
-        Pipeline pipeline = new Pipeline(
-            pipelineId,
-            null,
-            null,
-            new CompoundProcessor(
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); }),
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
-            )
-        );
+        Pipeline pipeline = new Pipeline(pipelineId, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        }), new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); }), new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key3, randomInt());
+        })));
         when(ingestService.getPipeline(pipelineId)).thenReturn(pipeline);
 
         PipelineProcessor pipelineProcessor = factory.create(Collections.emptyMap(), null, null, pipelineConfig);
@@ -406,29 +405,24 @@ public void testActualPipelineProcessorWithTrueConditional() throws Exception {
             new HashMap<>(ScriptModule.CORE_CONTEXTS)
         );
 
-        Pipeline pipeline1 = new Pipeline(
-            pipelineId1,
-            null,
-            null,
-            new CompoundProcessor(
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
-                new ConditionalProcessor(
-                    randomAlphaOfLength(10),
-                    null,
-                    new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
-                    scriptService,
-                    factory.create(Collections.emptyMap(), "pipeline1", null, pipelineConfig2)
-                ),
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
-            )
-        );
+        Pipeline pipeline1 = new Pipeline(pipelineId1, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        }),
+            new ConditionalProcessor(
+                randomAlphaOfLength(10),
+                null,
+                new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
+                scriptService,
+                factory.create(Collections.emptyMap(), "pipeline1", null, pipelineConfig2)
+            ),
+            new TestProcessor(ingestDocument -> {
+                ingestDocument.setFieldValue(key3, randomInt());
+            })
+        ));
 
-        Pipeline pipeline2 = new Pipeline(
-            pipelineId2,
-            null,
-            null,
-            new CompoundProcessor(new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); }))
-        );
+        Pipeline pipeline2 = new Pipeline(pipelineId2, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key2, randomInt());
+        })));
 
         when(ingestService.getPipeline(pipelineId1)).thenReturn(pipeline1);
         when(ingestService.getPipeline(pipelineId2)).thenReturn(pipeline2);
@@ -503,29 +497,24 @@ public void testActualPipelineProcessorWithFalseConditional() throws Exception {
             new HashMap<>(ScriptModule.CORE_CONTEXTS)
         );
 
-        Pipeline pipeline1 = new Pipeline(
-            pipelineId1,
-            null,
-            null,
-            new CompoundProcessor(
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
-                new ConditionalProcessor(
-                    randomAlphaOfLength(10),
-                    null,
-                    new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
-                    scriptService,
-                    factory.create(Collections.emptyMap(), null, null, pipelineConfig2)
-                ),
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
-            )
-        );
+        Pipeline pipeline1 = new Pipeline(pipelineId1, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        }),
+            new ConditionalProcessor(
+                randomAlphaOfLength(10),
+                null,
+                new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, scriptName, Collections.emptyMap()),
+                scriptService,
+                factory.create(Collections.emptyMap(), null, null, pipelineConfig2)
+            ),
+            new TestProcessor(ingestDocument -> {
+                ingestDocument.setFieldValue(key3, randomInt());
+            })
+        ));
 
-        Pipeline pipeline2 = new Pipeline(
-            pipelineId2,
-            null,
-            null,
-            new CompoundProcessor(new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); }))
-        );
+        Pipeline pipeline2 = new Pipeline(pipelineId2, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key2, randomInt());
+        })));
 
         when(ingestService.getPipeline(pipelineId1)).thenReturn(pipeline1);
         when(ingestService.getPipeline(pipelineId2)).thenReturn(pipeline2);
@@ -579,20 +568,18 @@ public void testActualPipelineProcessorWithHandledFailure() throws Exception {
         String key2 = randomAlphaOfLength(10);
         String key3 = randomAlphaOfLength(10);
 
-        Pipeline pipeline = new Pipeline(
-            pipelineId,
-            null,
-            null,
+        Pipeline pipeline = new Pipeline(pipelineId, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        }),
             new CompoundProcessor(
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }),
-                new CompoundProcessor(
-                    false,
-                    Collections.singletonList(new TestProcessor(ingestDocument -> { throw exception; })),
-                    Collections.singletonList(new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key2, randomInt()); }))
-                ),
-                new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
-            )
-        );
+                false,
+                Collections.singletonList(new TestProcessor(ingestDocument -> { throw exception; })),
+                Collections.singletonList(new TestProcessor(ingestDocument -> {
+                    ingestDocument.setFieldValue(key2, randomInt());
+                }))
+            ),
+            new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key3, randomInt()); })
+        ));
         when(ingestService.getPipeline(pipelineId)).thenReturn(pipeline);
 
         PipelineProcessor pipelineProcessor = factory.create(Collections.emptyMap(), null, null, pipelineConfig);
@@ -650,7 +637,9 @@ public void testActualPipelineProcessorWithUnhandledFailure() throws Exception {
             null,
             new CompoundProcessor(
                 new TestProcessor(ingestDocument -> ingestDocument.setFieldValue(key1, randomInt())),
-                new TestProcessor(ingestDocument -> { throw exception; })
+                new TestProcessor(ingestDocument -> {
+                    throw exception;
+                })
             )
         );
         when(ingestService.getPipeline(pipelineId)).thenReturn(pipeline);
@@ -730,12 +719,9 @@ public void testActualPipelineProcessorRepeatedInvocation() throws Exception {
 
         String key1 = randomAlphaOfLength(10);
         PipelineProcessor pipelineProcessor = factory.create(Collections.emptyMap(), null, null, pipelineConfig);
-        Pipeline pipeline = new Pipeline(
-            pipelineId,
-            null,
-            null,
-            new CompoundProcessor(new TestProcessor(ingestDocument -> { ingestDocument.setFieldValue(key1, randomInt()); }))
-        );
+        Pipeline pipeline = new Pipeline(pipelineId, null, null, new CompoundProcessor(new TestProcessor(ingestDocument -> {
+            ingestDocument.setFieldValue(key1, randomInt());
+        })));
         when(ingestService.getPipeline(pipelineId)).thenReturn(pipeline);
 
         // calls the same pipeline twice
diff --git a/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/DeDuplicatingTokenFilterTests.java b/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/DeDuplicatingTokenFilterTests.java
index 1bcb17a81efee..6e8b7ef5f5f42 100644
--- a/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/DeDuplicatingTokenFilterTests.java
+++ b/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/DeDuplicatingTokenFilterTests.java
@@ -33,13 +33,13 @@
 package org.opensearch.lucene.analysis.miscellaneous;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.miscellaneous.DeDuplicatingTokenFilter;
 import org.apache.lucene.analysis.miscellaneous.DuplicateByteSequenceSpotter;
 import org.apache.lucene.analysis.miscellaneous.DuplicateSequenceAttribute;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/TruncateTokenFilterTests.java b/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/TruncateTokenFilterTests.java
index bce9073f85bbe..f3a7436290a3b 100644
--- a/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/TruncateTokenFilterTests.java
+++ b/server/src/test/java/org/opensearch/lucene/analysis/miscellaneous/TruncateTokenFilterTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.lucene.analysis.miscellaneous;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.miscellaneous.TruncateTokenFilter;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.tests.analysis.MockTokenizer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/lucene/grouping/CollapsingTopDocsCollectorTests.java b/server/src/test/java/org/opensearch/lucene/grouping/CollapsingTopDocsCollectorTests.java
index 9a2a44abbb4ef..f425423d1cd82 100644
--- a/server/src/test/java/org/opensearch/lucene/grouping/CollapsingTopDocsCollectorTests.java
+++ b/server/src/test/java/org/opensearch/lucene/grouping/CollapsingTopDocsCollectorTests.java
@@ -40,8 +40,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexReaderContext;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
-import org.apache.lucene.tests.search.CheckHits;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.IndexSearcher;
@@ -59,6 +57,8 @@
 import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
 import org.apache.lucene.search.grouping.CollapsingTopDocsCollector;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.CheckHits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/lucene/index/ShuffleForcedMergePolicyTests.java b/server/src/test/java/org/opensearch/lucene/index/ShuffleForcedMergePolicyTests.java
index e583c12473a30..2f6581bfde8d4 100644
--- a/server/src/test/java/org/opensearch/lucene/index/ShuffleForcedMergePolicyTests.java
+++ b/server/src/test/java/org/opensearch/lucene/index/ShuffleForcedMergePolicyTests.java
@@ -36,7 +36,6 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.StringField;
-import org.apache.lucene.tests.index.BaseMergePolicyTestCase;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
@@ -48,6 +47,7 @@
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.BaseMergePolicyTestCase;
 
 import java.io.IOException;
 import java.util.function.Consumer;
@@ -58,7 +58,7 @@
 public class ShuffleForcedMergePolicyTests extends BaseMergePolicyTestCase {
     public void testDiagnostics() throws IOException {
         try (Directory dir = newDirectory()) {
-            IndexWriterConfig iwc = newIndexWriterConfig();
+            IndexWriterConfig iwc = newIndexWriterConfig().setMaxFullFlushMergeWaitMillis(0);
             MergePolicy mp = new ShuffleForcedMergePolicy(newTieredMergePolicy());
             iwc.setMergePolicy(mp);
             boolean sorted = random().nextBoolean();
diff --git a/server/src/test/java/org/opensearch/lucene/misc/search/similarity/LegacyBM25SimilarityTests.java b/server/src/test/java/org/opensearch/lucene/misc/search/similarity/LegacyBM25SimilarityTests.java
index 209b0d959c8b0..580789525522d 100644
--- a/server/src/test/java/org/opensearch/lucene/misc/search/similarity/LegacyBM25SimilarityTests.java
+++ b/server/src/test/java/org/opensearch/lucene/misc/search/similarity/LegacyBM25SimilarityTests.java
@@ -25,21 +25,20 @@
 
 package org.opensearch.lucene.misc.search.similarity;
 
-import java.util.Random;
-
 import org.apache.lucene.misc.search.similarity.LegacyBM25Similarity;
 import org.apache.lucene.search.similarities.BM25Similarity;
-import org.apache.lucene.tests.search.similarities.BaseSimilarityTestCase;
 import org.apache.lucene.search.similarities.Similarity;
+import org.apache.lucene.tests.search.similarities.BaseSimilarityTestCase;
+
+import java.util.Random;
 
 @Deprecated
 public class LegacyBM25SimilarityTests extends BaseSimilarityTestCase {
 
     public void testIllegalK1() {
-        IllegalArgumentException expected = expectThrows(
-            IllegalArgumentException.class,
-            () -> { new LegacyBM25Similarity(Float.POSITIVE_INFINITY, 0.75f); }
-        );
+        IllegalArgumentException expected = expectThrows(IllegalArgumentException.class, () -> {
+            new LegacyBM25Similarity(Float.POSITIVE_INFINITY, 0.75f);
+        });
         assertTrue(expected.getMessage().contains("illegal k1 value"));
 
         expected = expectThrows(IllegalArgumentException.class, () -> { new LegacyBM25Similarity(-1, 0.75f); });
diff --git a/server/src/test/java/org/opensearch/lucene/queries/BaseRandomBinaryDocValuesRangeQueryTestCase.java b/server/src/test/java/org/opensearch/lucene/queries/BaseRandomBinaryDocValuesRangeQueryTestCase.java
index 4e12c946cf353..5d49fbe2fbfa1 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/BaseRandomBinaryDocValuesRangeQueryTestCase.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/BaseRandomBinaryDocValuesRangeQueryTestCase.java
@@ -33,8 +33,8 @@
 
 import org.apache.lucene.document.BinaryDocValuesField;
 import org.apache.lucene.document.Field;
-import org.apache.lucene.tests.search.BaseRangeFieldQueryTestCase;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.tests.search.BaseRangeFieldQueryTestCase;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.mapper.RangeFieldMapper;
 import org.opensearch.index.mapper.RangeType;
diff --git a/server/src/test/java/org/opensearch/lucene/queries/BinaryDocValuesRangeQueryTests.java b/server/src/test/java/org/opensearch/lucene/queries/BinaryDocValuesRangeQueryTests.java
index faf84b53e0b16..0a1b38ed6f5ba 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/BinaryDocValuesRangeQueryTests.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/BinaryDocValuesRangeQueryTests.java
@@ -34,10 +34,10 @@
 import org.apache.lucene.document.BinaryDocValuesField;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.mapper.RangeFieldMapper;
 import org.opensearch.index.mapper.RangeType;
diff --git a/server/src/test/java/org/opensearch/lucene/queries/BlendedTermQueryTests.java b/server/src/test/java/org/opensearch/lucene/queries/BlendedTermQueryTests.java
index bf9aac344e3df..ca420bfbf8fbb 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/BlendedTermQueryTests.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/BlendedTermQueryTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.lucene.queries;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
@@ -47,7 +46,6 @@
 import org.apache.lucene.search.DisjunctionMaxQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TermQuery;
@@ -56,10 +54,12 @@
 import org.apache.lucene.search.similarities.ClassicSimilarity;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.Directory;
-import org.opensearch.test.OpenSearchTestCase;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils;
 import org.opensearch.test.EqualsHashCodeTestUtils.CopyFunction;
 import org.opensearch.test.EqualsHashCodeTestUtils.MutateFunction;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -112,7 +112,7 @@ public void testDismaxQuery() throws IOException {
             query.add(BlendedTermQuery.dismaxBlendedQuery(toTerms(fields, "generator"), 0.1f), BooleanClause.Occur.SHOULD);
             TopDocs search = searcher.search(query.build(), 10);
             ScoreDoc[] scoreDocs = search.scoreDocs;
-            assertEquals(Integer.toString(0), reader.document(scoreDocs[0].doc).getField("id").stringValue());
+            assertEquals(Integer.toString(0), reader.storedFields().document(scoreDocs[0].doc).getField("id").stringValue());
         }
         {
             BooleanQuery.Builder query = new BooleanQuery.Builder();
@@ -134,7 +134,7 @@ public void testDismaxQuery() throws IOException {
             query.add(gen, BooleanClause.Occur.SHOULD);
             TopDocs search = searcher.search(query.build(), 4);
             ScoreDoc[] scoreDocs = search.scoreDocs;
-            assertEquals(Integer.toString(1), reader.document(scoreDocs[0].doc).getField("id").stringValue());
+            assertEquals(Integer.toString(1), reader.storedFields().document(scoreDocs[0].doc).getField("id").stringValue());
 
         }
         {
@@ -269,7 +269,7 @@ public void testMinTTF() throws IOException {
             Query query = BlendedTermQuery.dismaxBlendedQuery(toTerms(fields, "foo"), 0.1f);
             TopDocs search = searcher.search(query, 10);
             ScoreDoc[] scoreDocs = search.scoreDocs;
-            assertEquals(Integer.toString(0), reader.document(scoreDocs[0].doc).getField("id").stringValue());
+            assertEquals(Integer.toString(0), reader.storedFields().document(scoreDocs[0].doc).getField("id").stringValue());
         }
         reader.close();
         w.close();
diff --git a/server/src/test/java/org/opensearch/lucene/queries/MinDocQueryTests.java b/server/src/test/java/org/opensearch/lucene/queries/MinDocQueryTests.java
index a75a1d5b2fdb7..fffb1b33fb563 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/MinDocQueryTests.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/MinDocQueryTests.java
@@ -35,11 +35,11 @@
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -61,10 +61,11 @@ public void testBasics() {
 
     public void testRewrite() throws Exception {
         IndexReader reader = new MultiReader();
+        IndexSearcher searcher = new IndexSearcher(reader);
         MinDocQuery query = new MinDocQuery(42);
-        Query rewritten = query.rewrite(reader);
+        Query rewritten = query.rewrite(searcher);
         QueryUtils.checkUnequal(query, rewritten);
-        Query rewritten2 = rewritten.rewrite(reader);
+        Query rewritten2 = rewritten.rewrite(searcher);
         assertSame(rewritten, rewritten2);
     }
 
diff --git a/server/src/test/java/org/opensearch/lucene/queries/SearchAfterSortedDocQueryTests.java b/server/src/test/java/org/opensearch/lucene/queries/SearchAfterSortedDocQueryTests.java
index 4920e252e7a6b..7d7aecbd4f08c 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/SearchAfterSortedDocQueryTests.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/SearchAfterSortedDocQueryTests.java
@@ -38,12 +38,10 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.ReaderUtil;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
@@ -51,6 +49,8 @@
 import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/lucene/queries/SpanMatchNoDocsQueryTests.java b/server/src/test/java/org/opensearch/lucene/queries/SpanMatchNoDocsQueryTests.java
index bf266af38fc59..834c94b04475a 100644
--- a/server/src/test/java/org/opensearch/lucene/queries/SpanMatchNoDocsQueryTests.java
+++ b/server/src/test/java/org/opensearch/lucene/queries/SpanMatchNoDocsQueryTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.lucene.queries;
 
 import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.DirectoryReader;
@@ -47,9 +46,10 @@
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -58,7 +58,7 @@ public class SpanMatchNoDocsQueryTests extends OpenSearchTestCase {
     public void testSimple() throws Exception {
         SpanMatchNoDocsQuery query = new SpanMatchNoDocsQuery("field", "a good reason");
         assertEquals(query.toString(), "SpanMatchNoDocsQuery(\"a good reason\")");
-        Query rewrite = query.rewrite(null);
+        Query rewrite = query.rewrite((IndexSearcher) null);
         assertTrue(rewrite instanceof SpanMatchNoDocsQuery);
         assertEquals(rewrite.toString(), "SpanMatchNoDocsQuery(\"a good reason\")");
     }
@@ -93,7 +93,7 @@ public void testQuery() throws Exception {
         assertEquals(searcher.count(orQuery), 1);
         hits = searcher.search(orQuery, 1000).scoreDocs;
         assertEquals(1, hits.length);
-        Query rewrite = orQuery.rewrite(ir);
+        Query rewrite = orQuery.rewrite(searcher);
         assertEquals(rewrite, orQuery);
 
         SpanNearQuery nearQuery = new SpanNearQuery(
@@ -104,7 +104,7 @@ public void testQuery() throws Exception {
         assertEquals(searcher.count(nearQuery), 0);
         hits = searcher.search(nearQuery, 1000).scoreDocs;
         assertEquals(0, hits.length);
-        rewrite = nearQuery.rewrite(ir);
+        rewrite = nearQuery.rewrite(searcher);
         assertEquals(rewrite, nearQuery);
 
         iw.close();
diff --git a/server/src/test/java/org/opensearch/lucene/search/uhighlight/CustomUnifiedHighlighterTests.java b/server/src/test/java/org/opensearch/lucene/search/uhighlight/CustomUnifiedHighlighterTests.java
index 5383a153034e9..1282b0152b57f 100644
--- a/server/src/test/java/org/opensearch/lucene/search/uhighlight/CustomUnifiedHighlighterTests.java
+++ b/server/src/test/java/org/opensearch/lucene/search/uhighlight/CustomUnifiedHighlighterTests.java
@@ -43,7 +43,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.CommonTermsQuery;
 import org.apache.lucene.search.BooleanClause;
@@ -63,15 +62,16 @@
 import org.apache.lucene.search.uhighlight.Snippet;
 import org.apache.lucene.search.uhighlight.UnifiedHighlighter;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.Strings;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.lucene.search.MultiPhrasePrefixQuery;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.text.BreakIterator;
 import java.util.Locale;
 
-import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 import static org.hamcrest.CoreMatchers.equalTo;
+import static org.apache.lucene.search.uhighlight.CustomUnifiedHighlighter.MULTIVAL_SEP_CHAR;
 
 public class CustomUnifiedHighlighterTests extends OpenSearchTestCase {
     private void assertHighlightOneDoc(
@@ -117,7 +117,8 @@ private void assertHighlightOneDoc(
                     noMatchSize,
                     expectedPassages.length,
                     name -> "text".equals(name),
-                    Integer.MAX_VALUE
+                    Integer.MAX_VALUE,
+                    null
                 );
                 final Snippet[] snippets = highlighter.highlightField(getOnlyLeafReader(reader), topDocs.scoreDocs[0].doc, () -> rawValue);
                 assertEquals(snippets.length, expectedPassages.length);
diff --git a/server/src/test/java/org/opensearch/monitor/fs/FsHealthServiceTests.java b/server/src/test/java/org/opensearch/monitor/fs/FsHealthServiceTests.java
index 0246c8a85e97a..a42c302b516d2 100644
--- a/server/src/test/java/org/opensearch/monitor/fs/FsHealthServiceTests.java
+++ b/server/src/test/java/org/opensearch/monitor/fs/FsHealthServiceTests.java
@@ -43,8 +43,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.monitor.StatusInfo;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -54,18 +54,18 @@
 import java.io.OutputStream;
 import java.nio.channels.FileChannel;
 import java.nio.file.FileSystem;
-import java.nio.file.Path;
 import java.nio.file.OpenOption;
+import java.nio.file.Path;
 import java.nio.file.attribute.FileAttribute;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.hamcrest.Matchers.equalTo;
 import static org.opensearch.monitor.StatusInfo.Status.HEALTHY;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 import static org.opensearch.node.Node.NODE_NAME_SETTING;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
 public class FsHealthServiceTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/monitor/fs/FsProbeTests.java b/server/src/test/java/org/opensearch/monitor/fs/FsProbeTests.java
index b70b76c23fb96..686a624d988d7 100644
--- a/server/src/test/java/org/opensearch/monitor/fs/FsProbeTests.java
+++ b/server/src/test/java/org/opensearch/monitor/fs/FsProbeTests.java
@@ -34,8 +34,15 @@
 
 import org.apache.lucene.util.Constants;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.NodeEnvironment.NodePath;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheFactory;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -64,7 +71,7 @@ public class FsProbeTests extends OpenSearchTestCase {
     public void testFsInfo() throws IOException {
 
         try (NodeEnvironment env = newNodeEnvironment()) {
-            FsProbe probe = new FsProbe(env);
+            FsProbe probe = new FsProbe(env, null);
 
             FsInfo stats = probe.stats(null);
             assertNotNull(stats);
@@ -103,6 +110,46 @@ public void testFsInfo() throws IOException {
                 assertThat(path.total, greaterThan(0L));
                 assertThat(path.free, greaterThan(0L));
                 assertThat(path.available, greaterThan(0L));
+                assertTrue(path.fileCacheReserved == 0);
+                assertTrue(path.fileCacheUtilized == 0);
+            }
+        }
+    }
+
+    public void testFsCacheInfo() throws IOException {
+        Settings settings = Settings.builder().put("node.roles", "search").build();
+        try (NodeEnvironment env = newNodeEnvironment(settings)) {
+            ByteSizeValue gbByteSizeValue = new ByteSizeValue(1, ByteSizeUnit.GB);
+            env.fileCacheNodePath().fileCacheReservedSize = gbByteSizeValue;
+            FileCache fileCache = FileCacheFactory.createConcurrentLRUFileCache(
+                gbByteSizeValue.getBytes(),
+                16,
+                new NoopCircuitBreaker(CircuitBreaker.REQUEST)
+            );
+            FsProbe probe = new FsProbe(env, fileCache);
+            FsInfo stats = probe.stats(null);
+            assertNotNull(stats);
+            assertTrue(stats.getTimestamp() > 0L);
+            FsInfo.Path total = stats.getTotal();
+            assertNotNull(total);
+            assertTrue(total.total > 0L);
+            assertTrue(total.free > 0L);
+            assertTrue(total.available > 0L);
+            assertTrue(total.fileCacheReserved > 0L);
+            assertTrue((total.free - total.available) >= total.fileCacheReserved);
+
+            for (FsInfo.Path path : stats) {
+                assertNotNull(path);
+                assertFalse(path.getPath().isEmpty());
+                assertFalse(path.getMount().isEmpty());
+                assertFalse(path.getType().isEmpty());
+                assertTrue(path.total > 0L);
+                assertTrue(path.free > 0L);
+                assertTrue(path.available > 0L);
+
+                if (path.fileCacheReserved > -1L) {
+                    assertTrue(path.free - path.available >= path.fileCacheReserved);
+                }
             }
         }
     }
@@ -173,7 +220,7 @@ public void testIoStats() {
             )
         );
 
-        final FsProbe probe = new FsProbe(null) {
+        final FsProbe probe = new FsProbe(null, null) {
             @Override
             List<String> readProcDiskStats() throws IOException {
                 return diskStats.get();
diff --git a/server/src/test/java/org/opensearch/monitor/jvm/JvmGcMonitorServiceTests.java b/server/src/test/java/org/opensearch/monitor/jvm/JvmGcMonitorServiceTests.java
index 3ea53bd0ea811..dbd8074da721c 100644
--- a/server/src/test/java/org/opensearch/monitor/jvm/JvmGcMonitorServiceTests.java
+++ b/server/src/test/java/org/opensearch/monitor/jvm/JvmGcMonitorServiceTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.monitor.jvm;
 
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.mockito.Mockito.mock;
diff --git a/server/src/test/java/org/opensearch/monitor/jvm/JvmInfoTests.java b/server/src/test/java/org/opensearch/monitor/jvm/JvmInfoTests.java
index d86971adcc992..3d02a4797497e 100644
--- a/server/src/test/java/org/opensearch/monitor/jvm/JvmInfoTests.java
+++ b/server/src/test/java/org/opensearch/monitor/jvm/JvmInfoTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.monitor.jvm;
 
 import org.apache.lucene.util.Constants;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.test.OpenSearchTestCase;
 
 public class JvmInfoTests extends OpenSearchTestCase {
@@ -53,14 +52,13 @@ private boolean isG1GCEnabled() {
         final String argline = System.getProperty("tests.jvm.argline");
         final boolean g1GCEnabled = flagIsEnabled(argline, "UseG1GC");
         // for JDK 9 the default collector when no collector is specified is G1 GC
-        final boolean versionIsAtLeastJava9 = JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0;
         final boolean noOtherCollectorSpecified = argline == null
             || (!flagIsEnabled(argline, "UseParNewGC")
                 && !flagIsEnabled(argline, "UseParallelGC")
                 && !flagIsEnabled(argline, "UseParallelOldGC")
                 && !flagIsEnabled(argline, "UseSerialGC")
                 && !flagIsEnabled(argline, "UseConcMarkSweepGC"));
-        return g1GCEnabled || (versionIsAtLeastJava9 && noOtherCollectorSpecified);
+        return g1GCEnabled || noOtherCollectorSpecified;
     }
 
     private boolean flagIsEnabled(String argline, String flag) {
diff --git a/server/src/test/java/org/opensearch/monitor/jvm/JvmStatsTests.java b/server/src/test/java/org/opensearch/monitor/jvm/JvmStatsTests.java
index 41a0891b73aa8..f9c39daef8aa8 100644
--- a/server/src/test/java/org/opensearch/monitor/jvm/JvmStatsTests.java
+++ b/server/src/test/java/org/opensearch/monitor/jvm/JvmStatsTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.monitor.jvm;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/monitor/os/OsProbeTests.java b/server/src/test/java/org/opensearch/monitor/os/OsProbeTests.java
index 505dce8879bdd..73f6ef8916a20 100644
--- a/server/src/test/java/org/opensearch/monitor/os/OsProbeTests.java
+++ b/server/src/test/java/org/opensearch/monitor/os/OsProbeTests.java
@@ -32,6 +32,20 @@
 
 package org.opensearch.monitor.os;
 
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.util.Constants;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.stream.Collectors;
+
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.CoreMatchers.nullValue;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.both;
@@ -42,19 +56,6 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.junit.Assume.assumeThat;
-
-import java.io.IOException;
-import java.math.BigInteger;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.Locale;
-import java.util.stream.Collectors;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.Constants;
-import org.opensearch.test.OpenSearchTestCase;
-
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
@@ -296,8 +297,12 @@ List<String> readSysFsCgroupCpuAcctCpuStat(String controlGroup) throws IOExcepti
             }
         };
 
-        assumeThat("CGroups are not available", noCpuStatsOsProbe.areCgroupStatsAvailable(), is(true));
-        noCpuStatsOsProbe.osStats();
+        assumeThat("CGroups are available", noCpuStatsOsProbe.areCgroupStatsAvailable(), is(true));
+        OsStats osStats = noCpuStatsOsProbe.osStats();
+
+        // Depending on CGroups v1/v2, the cgroup stats may not be available
+        assumeThat("CGroup is available", osStats.getCgroup(), is(not(nullValue())));
+
         // no nr_throttled and throttled_time
         verify(logger, times(2)).warn(anyString());
         reset(logger);
diff --git a/server/src/test/java/org/opensearch/monitor/os/OsStatsTests.java b/server/src/test/java/org/opensearch/monitor/os/OsStatsTests.java
index 66585962a8519..66f1c2c0cf981 100644
--- a/server/src/test/java/org/opensearch/monitor/os/OsStatsTests.java
+++ b/server/src/test/java/org/opensearch/monitor/os/OsStatsTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.monitor.os;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/node/InternalSettingsPreparerTests.java b/server/src/test/java/org/opensearch/node/InternalSettingsPreparerTests.java
index d49bc62583af7..d9b9769ecd11f 100644
--- a/server/src/test/java/org/opensearch/node/InternalSettingsPreparerTests.java
+++ b/server/src/test/java/org/opensearch/node/InternalSettingsPreparerTests.java
@@ -35,10 +35,10 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.SecureSetting;
-import org.opensearch.common.settings.SecureString;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.settings.SecureString;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
diff --git a/server/src/test/java/org/opensearch/node/NodeRoleSettingsTests.java b/server/src/test/java/org/opensearch/node/NodeRoleSettingsTests.java
index c875fec1979d1..0a3af34bc12f4 100644
--- a/server/src/test/java/org/opensearch/node/NodeRoleSettingsTests.java
+++ b/server/src/test/java/org/opensearch/node/NodeRoleSettingsTests.java
@@ -15,6 +15,7 @@
 
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.List;
 
 import static org.hamcrest.Matchers.containsString;
 
@@ -25,8 +26,7 @@ public class NodeRoleSettingsTests extends OpenSearchTestCase {
      * Remove the test after removing MASTER_ROLE.
      */
     public void testClusterManagerAndMasterRoleCanNotCoexist() {
-        // It's used to add MASTER_ROLE into 'roleMap', because MASTER_ROLE is removed from DiscoveryNodeRole.BUILT_IN_ROLES in 2.0.
-        DiscoveryNode.setAdditionalRoles(Collections.emptySet());
+        DiscoveryNode.setDeprecatedMasterRole();
         Settings roleSettings = Settings.builder().put(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), "cluster_manager, master").build();
         Exception exception = expectThrows(IllegalArgumentException.class, () -> NodeRoleSettings.NODE_ROLES_SETTING.get(roleSettings));
         assertThat(exception.getMessage(), containsString("[master, cluster_manager] can not be assigned together to a node"));
@@ -48,10 +48,28 @@ public void testClusterManagerAndDataNodeRoles() {
      * Remove the test after removing MASTER_ROLE.
      */
     public void testMasterRoleDeprecationMessage() {
-        // It's used to add MASTER_ROLE into 'roleMap', because MASTER_ROLE is removed from DiscoveryNodeRole.BUILT_IN_ROLES in 2.0.
-        DiscoveryNode.setAdditionalRoles(Collections.emptySet());
+        DiscoveryNode.setDeprecatedMasterRole();
         Settings roleSettings = Settings.builder().put(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), "master").build();
         assertEquals(Collections.singletonList(DiscoveryNodeRole.MASTER_ROLE), NodeRoleSettings.NODE_ROLES_SETTING.get(roleSettings));
         assertWarnings(DiscoveryNodeRole.MASTER_ROLE_DEPRECATION_MESSAGE);
     }
+
+    public void testUnknownNodeRoleAndBuiltInRoleCanCoexist() {
+        String testRole = "test_role";
+        Settings roleSettings = Settings.builder().put(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), "data, " + testRole).build();
+        List<DiscoveryNodeRole> nodeRoles = NodeRoleSettings.NODE_ROLES_SETTING.get(roleSettings);
+        assertEquals(2, nodeRoles.size());
+        assertEquals(DiscoveryNodeRole.DATA_ROLE, nodeRoles.get(0));
+        assertEquals(testRole, nodeRoles.get(1).roleName());
+        assertEquals(testRole, nodeRoles.get(1).roleNameAbbreviation());
+    }
+
+    public void testUnknownNodeRoleOnly() {
+        String testRole = "test_role";
+        Settings roleSettings = Settings.builder().put(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), testRole).build();
+        List<DiscoveryNodeRole> nodeRoles = NodeRoleSettings.NODE_ROLES_SETTING.get(roleSettings);
+        assertEquals(1, nodeRoles.size());
+        assertEquals(testRole, nodeRoles.get(0).roleName());
+        assertEquals(testRole, nodeRoles.get(0).roleNameAbbreviation());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/node/NodeTests.java b/server/src/test/java/org/opensearch/node/NodeTests.java
index 783fe1abdca17..d91dc696eb30b 100644
--- a/server/src/test/java/org/opensearch/node/NodeTests.java
+++ b/server/src/test/java/org/opensearch/node/NodeTests.java
@@ -32,26 +32,34 @@
 package org.opensearch.node;
 
 import org.apache.lucene.tests.util.LuceneTestCase;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.bootstrap.BootstrapCheck;
 import org.opensearch.bootstrap.BootstrapContext;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.breaker.CircuitBreaker;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
+import org.opensearch.common.settings.SettingsException;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.env.Environment;
+import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine.Searcher;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.breaker.BreakerSettings;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.monitor.fs.FsInfo;
+import org.opensearch.monitor.fs.FsProbe;
 import org.opensearch.plugins.CircuitBreakerPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockHttpTransport;
+import org.opensearch.test.NodeRoles;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
@@ -59,6 +67,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
@@ -66,6 +75,7 @@
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
+import static org.opensearch.test.NodeRoles.addRoles;
 import static org.opensearch.test.NodeRoles.dataNode;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
@@ -346,6 +356,54 @@ public void testCreateWithCircuitBreakerPlugins() throws IOException {
         }
     }
 
+    public void testCreateWithFileCache() throws Exception {
+        Settings searchRoleSettings = addRoles(baseSettings().build(), Set.of(DiscoveryNodeRole.SEARCH_ROLE));
+        List<Class<? extends Plugin>> plugins = basePlugins();
+        ByteSizeValue cacheSize = new ByteSizeValue(16, ByteSizeUnit.GB);
+        Settings searchRoleSettingsWithConfig = baseSettings().put(searchRoleSettings)
+            .put(Node.NODE_SEARCH_CACHE_SIZE_SETTING.getKey(), cacheSize)
+            .build();
+        Settings onlySearchRoleSettings = Settings.builder()
+            .put(searchRoleSettingsWithConfig)
+            .put(
+                NodeRoles.removeRoles(
+                    searchRoleSettingsWithConfig,
+                    Set.of(
+                        DiscoveryNodeRole.DATA_ROLE,
+                        DiscoveryNodeRole.CLUSTER_MANAGER_ROLE,
+                        DiscoveryNodeRole.INGEST_ROLE,
+                        DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE
+                    )
+                )
+            )
+            .build();
+
+        // Test exception thrown with configuration missing
+        assertThrows(SettingsException.class, () -> new MockNode(searchRoleSettings, plugins));
+
+        // Test file cache is initialized
+        try (MockNode mockNode = new MockNode(searchRoleSettingsWithConfig, plugins)) {
+            NodeEnvironment.NodePath fileCacheNodePath = mockNode.getNodeEnvironment().fileCacheNodePath();
+            assertEquals(cacheSize.getBytes(), fileCacheNodePath.fileCacheReservedSize.getBytes());
+        }
+
+        // Test data + search node with defined cache size
+        try (MockNode mockNode = new MockNode(searchRoleSettingsWithConfig, plugins)) {
+            NodeEnvironment.NodePath fileCacheNodePath = mockNode.getNodeEnvironment().fileCacheNodePath();
+            assertEquals(cacheSize.getBytes(), fileCacheNodePath.fileCacheReservedSize.getBytes());
+        }
+
+        // Test dedicated search node with no configuration
+        try (MockNode mockNode = new MockNode(onlySearchRoleSettings, plugins)) {
+            NodeEnvironment.NodePath fileCacheNodePath = mockNode.getNodeEnvironment().fileCacheNodePath();
+            assertTrue(fileCacheNodePath.fileCacheReservedSize.getBytes() > 0);
+            FsProbe fsProbe = new FsProbe(mockNode.getNodeEnvironment(), mockNode.fileCache());
+            FsInfo fsInfo = fsProbe.stats(null);
+            FsInfo.Path cachePathInfo = fsInfo.iterator().next();
+            assertEquals(cachePathInfo.getFileCacheReserved().getBytes(), fileCacheNodePath.fileCacheReservedSize.getBytes());
+        }
+    }
+
     public static class MockCircuitBreakerPlugin extends Plugin implements CircuitBreakerPlugin {
 
         private SetOnce<CircuitBreaker> myCircuitBreaker = new SetOnce<>();
diff --git a/server/src/test/java/org/opensearch/node/RemoteStoreNodeAttributeTests.java b/server/src/test/java/org/opensearch/node/RemoteStoreNodeAttributeTests.java
new file mode 100644
index 0000000000000..c4ba271d27ae9
--- /dev/null
+++ b/server/src/test/java/org/opensearch/node/RemoteStoreNodeAttributeTests.java
@@ -0,0 +1,151 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.node;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.metadata.CryptoMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.node.remotestore.RemoteStoreNodeAttribute;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Locale;
+import java.util.Map;
+
+import static java.util.Collections.emptySet;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_CRYPTO_SETTINGS_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+
+public class RemoteStoreNodeAttributeTests extends OpenSearchTestCase {
+
+    static private final String KEY_ARN = "arn:aws:kms:us-east-1:123456789:key/6e9aa906-2cc3-4924-8ded-f385c78d9dcf";
+    static private final String REGION = "us-east-1";
+
+    public void testCryptoMetadata() throws UnknownHostException {
+        String repoName = "remote-store-A";
+        String repoTypeSettingKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, repoName);
+        String repoSettingsKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX, repoName);
+        String repoCryptoMetadataKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT, repoName);
+        String repoCryptoMetadataSettingsKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_CRYPTO_SETTINGS_PREFIX, repoName);
+        Map<String, String> attr = Map.of(
+            REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            repoTypeSettingKey,
+            "s3",
+            repoSettingsKey,
+            "abc",
+            repoSettingsKey + "base_path",
+            "xyz",
+            repoCryptoMetadataKey + ".key_provider_name",
+            "store-test",
+            repoCryptoMetadataKey + ".key_provider_type",
+            "aws-kms",
+            repoCryptoMetadataSettingsKey + ".region",
+            REGION,
+            repoCryptoMetadataSettingsKey + ".key_arn",
+            KEY_ARN
+        );
+        DiscoveryNode node = new DiscoveryNode(
+            "C",
+            new TransportAddress(InetAddress.getByName("localhost"), 9876),
+            attr,
+            emptySet(),
+            Version.CURRENT
+        );
+
+        RemoteStoreNodeAttribute remoteStoreNodeAttribute = new RemoteStoreNodeAttribute(node);
+        assertEquals(remoteStoreNodeAttribute.getRepositoriesMetadata().repositories().size(), 1);
+        RepositoryMetadata repositoryMetadata = remoteStoreNodeAttribute.getRepositoriesMetadata().repositories().get(0);
+        Settings.Builder settings = Settings.builder();
+        settings.put("region", REGION);
+        settings.put("key_arn", KEY_ARN);
+        CryptoMetadata cryptoMetadata = new CryptoMetadata("store-test", "aws-kms", settings.build());
+        assertEquals(cryptoMetadata, repositoryMetadata.cryptoMetadata());
+    }
+
+    public void testInvalidCryptoMetadata() throws UnknownHostException {
+        String repoName = "remote-store-A";
+        String repoTypeSettingKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, repoName);
+        String repoSettingsKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX, repoName);
+        String repoCryptoMetadataKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_CRYPTO_ATTRIBUTE_KEY_FORMAT, repoName);
+        String repoCryptoMetadataSettingsKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_CRYPTO_SETTINGS_PREFIX, repoName);
+        Map<String, String> attr = Map.of(
+            REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            repoTypeSettingKey,
+            "s3",
+            repoSettingsKey,
+            "abc",
+            repoSettingsKey + "base_path",
+            "xyz",
+            repoCryptoMetadataSettingsKey + ".region",
+            REGION,
+            repoCryptoMetadataSettingsKey + ".key_arn",
+            KEY_ARN
+        );
+        DiscoveryNode node = new DiscoveryNode(
+            "C",
+            new TransportAddress(InetAddress.getByName("localhost"), 9876),
+            attr,
+            emptySet(),
+            Version.CURRENT
+        );
+
+        assertThrows(IllegalStateException.class, () -> new RemoteStoreNodeAttribute(node));
+    }
+
+    public void testNoCryptoMetadata() throws UnknownHostException {
+        String repoName = "remote-store-A";
+        String repoTypeSettingKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT, repoName);
+        String repoSettingsKey = String.format(Locale.ROOT, REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX, repoName);
+        Map<String, String> attr = Map.of(
+            REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY,
+            repoName,
+            repoTypeSettingKey,
+            "s3",
+            repoSettingsKey,
+            "abc",
+            repoSettingsKey + "base_path",
+            "xyz"
+        );
+        DiscoveryNode node = new DiscoveryNode(
+            "C",
+            new TransportAddress(InetAddress.getByName("localhost"), 9876),
+            attr,
+            emptySet(),
+            Version.CURRENT
+        );
+
+        RemoteStoreNodeAttribute remoteStoreNodeAttribute = new RemoteStoreNodeAttribute(node);
+        assertEquals(remoteStoreNodeAttribute.getRepositoriesMetadata().repositories().size(), 1);
+        RepositoryMetadata repositoryMetadata = remoteStoreNodeAttribute.getRepositoriesMetadata().repositories().get(0);
+        assertNull(repositoryMetadata.cryptoMetadata());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/node/ResponseCollectorServiceTests.java b/server/src/test/java/org/opensearch/node/ResponseCollectorServiceTests.java
index 2b13df3027cfa..7ca1f1e864b99 100644
--- a/server/src/test/java/org/opensearch/node/ResponseCollectorServiceTests.java
+++ b/server/src/test/java/org/opensearch/node/ResponseCollectorServiceTests.java
@@ -40,7 +40,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/nodesinfo/NodeInfoStreamingTests.java b/server/src/test/java/org/opensearch/nodesinfo/NodeInfoStreamingTests.java
index c0426078e8020..fba26b0c72e0e 100644
--- a/server/src/test/java/org/opensearch/nodesinfo/NodeInfoStreamingTests.java
+++ b/server/src/test/java/org/opensearch/nodesinfo/NodeInfoStreamingTests.java
@@ -36,15 +36,14 @@
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.PluginsAndModules;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.ingest.IngestInfo;
 import org.opensearch.ingest.ProcessorInfo;
@@ -54,6 +53,7 @@
 import org.opensearch.plugins.PluginInfo;
 import org.opensearch.search.aggregations.support.AggregationInfo;
 import org.opensearch.search.aggregations.support.AggregationUsageService;
+import org.opensearch.search.pipeline.SearchPipelineInfo;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.threadpool.ThreadPool;
@@ -118,7 +118,7 @@ private void compareJsonOutput(ToXContent param1, ToXContent param2) throws IOEx
         param2Builder.startObject();
         param2.toXContent(param2Builder, params);
         param2Builder.endObject();
-        assertThat(Strings.toString(param1Builder), equalTo(Strings.toString(param2Builder)));
+        assertThat(param1Builder.toString(), equalTo(param2Builder.toString()));
     }
 
     private static NodeInfo createNodeInfo() {
@@ -242,6 +242,17 @@ private static NodeInfo createNodeInfo() {
             // pick a random long that sometimes exceeds an int:
             indexingBuffer = new ByteSizeValue(random().nextLong() & ((1L << 40) - 1));
         }
+
+        SearchPipelineInfo searchPipelineInfo = null;
+        if (randomBoolean()) {
+            int numProcessors = randomIntBetween(0, 5);
+            List<org.opensearch.search.pipeline.ProcessorInfo> processors = new ArrayList<>(numProcessors);
+            for (int i = 0; i < numProcessors; i++) {
+                processors.add(new org.opensearch.search.pipeline.ProcessorInfo(randomAlphaOfLengthBetween(3, 10)));
+            }
+            searchPipelineInfo = new SearchPipelineInfo(Map.of(randomAlphaOfLengthBetween(3, 10), processors));
+        }
+
         return new NodeInfo(
             VersionUtils.randomVersion(random()),
             build,
@@ -256,7 +267,8 @@ private static NodeInfo createNodeInfo() {
             pluginsAndModules,
             ingestInfo,
             aggregationInfo,
-            indexingBuffer
+            indexingBuffer,
+            searchPipelineInfo
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/persistent/CancelPersistentTaskRequestTests.java b/server/src/test/java/org/opensearch/persistent/CancelPersistentTaskRequestTests.java
index 6fb61bc08729f..dae7a93e02596 100644
--- a/server/src/test/java/org/opensearch/persistent/CancelPersistentTaskRequestTests.java
+++ b/server/src/test/java/org/opensearch/persistent/CancelPersistentTaskRequestTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.RemovePersistentTaskAction.Request;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/persistent/PersistentTasksClusterServiceTests.java b/server/src/test/java/org/opensearch/persistent/PersistentTasksClusterServiceTests.java
index bb8f0405ecf7e..68b35dc1fb906 100644
--- a/server/src/test/java/org/opensearch/persistent/PersistentTasksClusterServiceTests.java
+++ b/server/src/test/java/org/opensearch/persistent/PersistentTasksClusterServiceTests.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.persistent;
 
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
@@ -50,6 +48,7 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestParams;
@@ -153,7 +152,7 @@ public void testReassignmentRequiredOnMetadataChanges() {
         DiscoveryNodes nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("_node", buildNewFakeTransportAddress(), Version.CURRENT))
             .localNodeId("_node")
-            .masterNodeId("_node")
+            .clusterManagerNodeId("_node")
             .build();
 
         boolean unassigned = randomBoolean();
@@ -201,7 +200,7 @@ public void testReassignmentRequiredOnMetadataChanges() {
 
     public void testReassignTasksWithNoTasks() {
         ClusterState clusterState = initialState();
-        assertThat(reassign(clusterState).metadata().custom(PersistentTasksCustomMetadata.TYPE), nullValue());
+        assertThat(reassign(createService(), clusterState).metadata().custom(PersistentTasksCustomMetadata.TYPE), nullValue());
     }
 
     public void testReassignConsidersClusterStateUpdates() {
@@ -219,7 +218,7 @@ public void testReassignConsidersClusterStateUpdates() {
 
         Metadata.Builder metadata = Metadata.builder(clusterState.metadata()).putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build());
         clusterState = builder.metadata(metadata).nodes(nodes).build();
-        ClusterState newClusterState = reassign(clusterState);
+        ClusterState newClusterState = reassign(createService(), clusterState);
 
         PersistentTasksCustomMetadata tasksInProgress = newClusterState.getMetadata().custom(PersistentTasksCustomMetadata.TYPE);
         assertThat(tasksInProgress, notNullValue());
@@ -238,7 +237,8 @@ public void testNonClusterStateConditionAssignment() {
         clusterState = builder.metadata(metadata).nodes(nodes).build();
 
         nonClusterStateCondition = false;
-        ClusterState newClusterState = reassign(clusterState);
+        PersistentTasksClusterService service = createService();
+        ClusterState newClusterState = reassign(service, clusterState);
 
         PersistentTasksCustomMetadata tasksInProgress = newClusterState.getMetadata().custom(PersistentTasksCustomMetadata.TYPE);
         assertThat(tasksInProgress, notNullValue());
@@ -250,7 +250,7 @@ public void testNonClusterStateConditionAssignment() {
         assertThat(tasksInProgress.tasks().size(), equalTo(1));
 
         nonClusterStateCondition = true;
-        ClusterState finalClusterState = reassign(newClusterState);
+        ClusterState finalClusterState = reassign(service, newClusterState);
 
         tasksInProgress = finalClusterState.getMetadata().custom(PersistentTasksCustomMetadata.TYPE);
         assertThat(tasksInProgress, notNullValue());
@@ -289,7 +289,7 @@ public void testReassignTasks() {
         }
         Metadata.Builder metadata = Metadata.builder(clusterState.metadata()).putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build());
         clusterState = builder.metadata(metadata).nodes(nodes).build();
-        ClusterState newClusterState = reassign(clusterState);
+        ClusterState newClusterState = reassign(createService(), clusterState);
 
         PersistentTasksCustomMetadata tasksInProgress = newClusterState.getMetadata().custom(PersistentTasksCustomMetadata.TYPE);
         assertThat(tasksInProgress, notNullValue());
@@ -494,7 +494,7 @@ public void testPeriodicRecheck() throws Exception {
         });
     }
 
-    public void testPeriodicRecheckOffMaster() {
+    public void testPeriodicRecheckOffClusterManager() {
         ClusterState initialState = initialState();
         ClusterState.Builder builder = ClusterState.builder(initialState);
         PersistentTasksCustomMetadata.Builder tasks = PersistentTasksCustomMetadata.builder(
@@ -528,20 +528,20 @@ public void testPeriodicRecheckOffMaster() {
             assertThat(tasksInProgress.tasks().size(), equalTo(1));
         }
 
-        // The rechecker should recheck indefinitely on the master node as the
+        // The rechecker should recheck indefinitely on the cluster-manager node as the
         // task can never be assigned while nonClusterStateCondition = false
         assertTrue(service.getPeriodicRechecker().isScheduled());
 
-        // Now simulate the node ceasing to be the master
+        // Now simulate the node ceasing to be the cluster-manager
         builder = ClusterState.builder(clusterState);
         nodes = DiscoveryNodes.builder(clusterState.nodes());
-        nodes.add(DiscoveryNode.createLocal(Settings.EMPTY, buildNewFakeTransportAddress(), "a_new_master_node"));
-        nodes.masterNodeId("a_new_master_node");
+        nodes.add(DiscoveryNode.createLocal(Settings.EMPTY, buildNewFakeTransportAddress(), "a_new_cluster_manager_node"));
+        nodes.clusterManagerNodeId("a_new_cluster_manager_node");
         ClusterState nonMasterClusterState = builder.nodes(nodes).build();
         event = new ClusterChangedEvent("test", nonMasterClusterState, clusterState);
         service.clusterChanged(event);
 
-        // The service should have cancelled the rechecker on learning it is no longer running on the master node
+        // The service should have cancelled the rechecker on learning it is no longer running on the cluster-manager node
         assertFalse(service.getPeriodicRechecker().isScheduled());
     }
 
@@ -554,7 +554,7 @@ public void testUnassignTask() {
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("_node_1", buildNewFakeTransportAddress(), Version.CURRENT))
             .localNodeId("_node_1")
-            .masterNodeId("_node_1")
+            .clusterManagerNodeId("_node_1")
             .add(new DiscoveryNode("_node_2", buildNewFakeTransportAddress(), Version.CURRENT));
 
         String unassignedId = addTask(tasks, "unassign", "_node_2");
@@ -579,7 +579,7 @@ public void testUnassignNonExistentTask() {
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("_node_1", buildNewFakeTransportAddress(), Version.CURRENT))
             .localNodeId("_node_1")
-            .masterNodeId("_node_1")
+            .clusterManagerNodeId("_node_1")
             .add(new DiscoveryNode("_node_2", buildNewFakeTransportAddress(), Version.CURRENT));
 
         Metadata.Builder metadata = Metadata.builder(clusterState.metadata()).putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build());
@@ -624,8 +624,8 @@ private void addTestNodes(DiscoveryNodes.Builder nodes, int nonLocalNodesCount)
         }
     }
 
-    private ClusterState reassign(ClusterState clusterState) {
-        PersistentTasksClusterService service = createService((params, currentState) -> {
+    private PersistentTasksClusterService createService() {
+        return createService((params, currentState) -> {
             TestParams testParams = (TestParams) params;
             switch (testParams.getTestParam()) {
                 case "assign_me":
@@ -644,7 +644,9 @@ private ClusterState reassign(ClusterState clusterState) {
             }
             return NO_NODE_FOUND;
         });
+    }
 
+    private ClusterState reassign(PersistentTasksClusterService service, ClusterState clusterState) {
         return service.reassignTasks(clusterState);
     }
 
@@ -674,8 +676,8 @@ private Assignment randomNodeAssignment(DiscoveryNodes nodes) {
             return NO_NODE_FOUND;
         }
         List<String> nodeList = new ArrayList<>();
-        for (ObjectCursor<String> node : nodes.getNodes().keys()) {
-            nodeList.add(node.value);
+        for (final String node : nodes.getNodes().keySet()) {
+            nodeList.add(node);
         }
         String node = randomFrom(nodeList);
         if (node != null) {
@@ -796,7 +798,7 @@ private ClusterState insignificantChange(ClusterState clusterState) {
             }
         }
         if (randomBoolean()) {
-            // remove a node that doesn't have any tasks assigned to it and it's not the master node
+            // remove a node that doesn't have any tasks assigned to it and it's not the cluster-manager node
             for (DiscoveryNode node : clusterState.nodes()) {
                 if (hasTasksAssignedTo(tasks, node.getId()) == false && "this_node".equals(node.getId()) == false) {
                     logger.info("removed unassigned node {}", node.getId());
@@ -902,7 +904,7 @@ private ClusterState initialState() {
         DiscoveryNodes.Builder nodes = DiscoveryNodes.builder();
         nodes.add(DiscoveryNode.createLocal(Settings.EMPTY, buildNewFakeTransportAddress(), "this_node"));
         nodes.localNodeId("this_node");
-        nodes.masterNodeId("this_node");
+        nodes.clusterManagerNodeId("this_node");
 
         return ClusterState.builder(ClusterName.DEFAULT).nodes(nodes).metadata(metadata).routingTable(routingTable.build()).build();
     }
diff --git a/server/src/test/java/org/opensearch/persistent/PersistentTasksCustomMetadataTests.java b/server/src/test/java/org/opensearch/persistent/PersistentTasksCustomMetadataTests.java
index 873176f5d42be..62ed9692de260 100644
--- a/server/src/test/java/org/opensearch/persistent/PersistentTasksCustomMetadataTests.java
+++ b/server/src/test/java/org/opensearch/persistent/PersistentTasksCustomMetadataTests.java
@@ -41,22 +41,21 @@
 import org.opensearch.cluster.metadata.Metadata.Custom;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.ParseField;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Builder;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
@@ -204,7 +203,7 @@ public void testSerializationContext() throws Exception {
         BytesReference shuffled = toShuffledXContent(testInstance, xContentType, params, false);
 
         PersistentTasksCustomMetadata newInstance;
-        try (XContentParser parser = createParser(XContentFactory.xContent(xContentType), shuffled)) {
+        try (XContentParser parser = createParser(xContentType.xContent(), shuffled)) {
             newInstance = doParseInstance(parser);
         }
         assertNotSame(newInstance, testInstance);
@@ -330,7 +329,7 @@ public void testDisassociateDeadNodes_givenAssignedPersistentTask() {
         DiscoveryNodes nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("node1", buildNewFakeTransportAddress(), Version.CURRENT))
             .localNodeId("node1")
-            .masterNodeId("node1")
+            .clusterManagerNodeId("node1")
             .build();
 
         String taskName = "test/task";
@@ -358,7 +357,7 @@ public void testDisassociateDeadNodes() {
         DiscoveryNodes nodes = DiscoveryNodes.builder()
             .add(new DiscoveryNode("node1", buildNewFakeTransportAddress(), Version.CURRENT))
             .localNodeId("node1")
-            .masterNodeId("node1")
+            .clusterManagerNodeId("node1")
             .build();
 
         String taskName = "test/task";
diff --git a/server/src/test/java/org/opensearch/persistent/PersistentTasksExecutorResponseTests.java b/server/src/test/java/org/opensearch/persistent/PersistentTasksExecutorResponseTests.java
index 22c2946fbcf40..6fad572bb4263 100644
--- a/server/src/test/java/org/opensearch/persistent/PersistentTasksExecutorResponseTests.java
+++ b/server/src/test/java/org/opensearch/persistent/PersistentTasksExecutorResponseTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.persistent;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestPersistentTasksExecutor;
 import org.opensearch.test.AbstractWireSerializingTestCase;
diff --git a/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceStatusTests.java b/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceStatusTests.java
index 9627fb96ff254..f6f9289e656b3 100644
--- a/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceStatusTests.java
+++ b/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceStatusTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.test.AbstractWireSerializingTestCase;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.PersistentTasksNodeService.Status;
+import org.opensearch.test.AbstractWireSerializingTestCase;
 
 import static org.hamcrest.Matchers.containsString;
 
diff --git a/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceTests.java b/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceTests.java
index 84ca449bec665..a97e3504f4d34 100644
--- a/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceTests.java
+++ b/server/src/test/java/org/opensearch/persistent/PersistentTasksNodeServiceTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.persistent;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterChangedEvent;
@@ -47,12 +46,13 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestParams;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestPersistentTasksExecutor;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
diff --git a/server/src/test/java/org/opensearch/persistent/RestartPersistentTaskRequestTests.java b/server/src/test/java/org/opensearch/persistent/RestartPersistentTaskRequestTests.java
index 28503d0eba512..5adf8594cd983 100644
--- a/server/src/test/java/org/opensearch/persistent/RestartPersistentTaskRequestTests.java
+++ b/server/src/test/java/org/opensearch/persistent/RestartPersistentTaskRequestTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.persistent;
 
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.CompletionPersistentTaskAction.Request;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/persistent/StartPersistentActionRequestTests.java b/server/src/test/java/org/opensearch/persistent/StartPersistentActionRequestTests.java
index fef2c88f0d61a..fe733525c6779 100644
--- a/server/src/test/java/org/opensearch/persistent/StartPersistentActionRequestTests.java
+++ b/server/src/test/java/org/opensearch/persistent/StartPersistentActionRequestTests.java
@@ -32,9 +32,9 @@
 package org.opensearch.persistent;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.StartPersistentTaskAction.Request;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestParams;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestPersistentTasksExecutor;
diff --git a/server/src/test/java/org/opensearch/persistent/TestPersistentTasksPlugin.java b/server/src/test/java/org/opensearch/persistent/TestPersistentTasksPlugin.java
index 977f5ebb7a80f..0a1893173e8a7 100644
--- a/server/src/test/java/org/opensearch/persistent/TestPersistentTasksPlugin.java
+++ b/server/src/test/java/org/opensearch/persistent/TestPersistentTasksPlugin.java
@@ -35,10 +35,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
-import org.opensearch.action.ActionType;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
+import org.opensearch.action.ActionType;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.support.ActionFilters;
@@ -52,26 +50,29 @@
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.Strings;
-import org.opensearch.common.component.Lifecycle;
 import org.opensearch.common.inject.Inject;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.common.settings.SettingsModule;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.Assignment;
 import org.opensearch.persistent.PersistentTasksCustomMetadata.PersistentTask;
 import org.opensearch.plugins.ActionPlugin;
 import org.opensearch.plugins.PersistentTaskPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.tasks.TaskCancelledException;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
@@ -88,7 +89,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Objects.requireNonNull;
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.test.OpenSearchTestCase.assertBusy;
 import static org.opensearch.test.OpenSearchTestCase.randomBoolean;
 import static org.junit.Assert.assertTrue;
@@ -177,7 +178,7 @@ public TestParams(StreamInput in) throws IOException {
             executorNodeAttr = in.readOptionalString();
             responseNode = in.readOptionalString();
             testParam = in.readOptionalString();
-            minVersion = Version.readVersion(in);
+            minVersion = in.readVersion();
             feature = Optional.ofNullable(in.readOptionalString());
         }
 
@@ -207,7 +208,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeOptionalString(executorNodeAttr);
             out.writeOptionalString(responseNode);
             out.writeOptionalString(testParam);
-            Version.writeVersion(minVersion, out);
+            out.writeVersion(minVersion);
             out.writeOptionalString(feature.orElse(null));
         }
 
@@ -299,7 +300,7 @@ public void writeTo(StreamOutput out) throws IOException {
 
         @Override
         public String toString() {
-            return Strings.toString(this);
+            return Strings.toString(MediaTypeRegistry.JSON, this);
         }
 
         // Implements equals and hashcode for testing
diff --git a/server/src/test/java/org/opensearch/persistent/UpdatePersistentTaskRequestTests.java b/server/src/test/java/org/opensearch/persistent/UpdatePersistentTaskRequestTests.java
index 06f426da34db5..e8a7ad1652139 100644
--- a/server/src/test/java/org/opensearch/persistent/UpdatePersistentTaskRequestTests.java
+++ b/server/src/test/java/org/opensearch/persistent/UpdatePersistentTaskRequestTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.persistent;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.persistent.TestPersistentTasksPlugin.State;
 import org.opensearch.persistent.TestPersistentTasksPlugin.TestPersistentTasksExecutor;
 import org.opensearch.persistent.UpdatePersistentTaskStatusAction.Request;
diff --git a/server/src/test/java/org/opensearch/plugins/ClusterPluginTests.java b/server/src/test/java/org/opensearch/plugins/ClusterPluginTests.java
new file mode 100644
index 0000000000000..c90d4e2789e82
--- /dev/null
+++ b/server/src/test/java/org/opensearch/plugins/ClusterPluginTests.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
+import java.util.Collection;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+public class ClusterPluginTests extends OpenSearchSingleNodeTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return pluginList(DummyClusterPlugin.class, DummyClusterPlugin2.class);
+    }
+
+    public void testOnNodeStarted_shouldContainLocalNodeInfo() {
+
+        DiscoveryNode localNode = DummyClusterPlugin.getLocalNode();
+
+        assertTrue(localNode != null);
+        // TODO Figure out if there is a way to check ephemeralId
+        assertTrue(localNode.getId().equals(node().getNodeEnvironment().nodeId()));
+    }
+
+    public void testOnNodeStarted_shouldCallDeprecatedMethod() {
+        DummyClusterPlugin2 dummyClusterPlugin2 = mock(DummyClusterPlugin2.class);
+        dummyClusterPlugin2.onNodeStarted();
+        verify(dummyClusterPlugin2, times(1)).onNodeStarted();
+
+        DiscoveryNode localNode = DummyClusterPlugin2.getLocalNode();
+        assertTrue(localNode != null);
+    }
+
+}
+
+final class DummyClusterPlugin extends Plugin implements ClusterPlugin {
+
+    private static volatile DiscoveryNode localNode;
+
+    public DummyClusterPlugin() {}
+
+    @Override
+    public void onNodeStarted(DiscoveryNode localNode) {
+        DummyClusterPlugin.localNode = localNode;
+    }
+
+    public static DiscoveryNode getLocalNode() {
+        return localNode;
+    }
+}
+
+class DummyClusterPlugin2 extends Plugin implements ClusterPlugin {
+
+    private static volatile DiscoveryNode localNode;
+
+    public DummyClusterPlugin2() {}
+
+    @Override
+    public void onNodeStarted() {
+        localNode = mock(DiscoveryNode.class);
+    }
+
+    public static DiscoveryNode getLocalNode() {
+        return localNode;
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/plugins/IndexStorePluginTests.java b/server/src/test/java/org/opensearch/plugins/IndexStorePluginTests.java
index 165e3aaf3f171..5fd76fc90568c 100644
--- a/server/src/test/java/org/opensearch/plugins/IndexStorePluginTests.java
+++ b/server/src/test/java/org/opensearch/plugins/IndexStorePluginTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.plugins;
 
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.settings.Settings;
@@ -134,25 +133,16 @@ public void testDuplicateIndexStoreFactories() {
             IllegalStateException.class,
             () -> new MockNode(settings, Arrays.asList(BarStorePlugin.class, FooStorePlugin.class))
         );
-        if (JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0) {
-            assertThat(
-                e,
-                hasToString(
-                    matches(
-                        "java.lang.IllegalStateException: Duplicate key store \\(attempted merging values "
-                            + "org.opensearch.index.store.FsDirectoryFactory@[\\w\\d]+ "
-                            + "and org.opensearch.index.store.FsDirectoryFactory@[\\w\\d]+\\)"
-                    )
-                )
-            );
-        } else {
-            assertThat(
-                e,
-                hasToString(
-                    matches("java.lang.IllegalStateException: Duplicate key org.opensearch.index.store.FsDirectoryFactory@[\\w\\d]+")
+        assertThat(
+            e,
+            hasToString(
+                matches(
+                    "java.lang.IllegalStateException: Duplicate key store \\(attempted merging values "
+                        + "org.opensearch.index.store.FsDirectoryFactory@[\\w\\d]+ "
+                        + "and org.opensearch.index.store.FsDirectoryFactory@[\\w\\d]+\\)"
                 )
-            );
-        }
+            )
+        );
     }
 
     public void testDuplicateIndexStoreRecoveryStateFactories() {
@@ -161,18 +151,6 @@ public void testDuplicateIndexStoreRecoveryStateFactories() {
             IllegalStateException.class,
             () -> new MockNode(settings, Arrays.asList(FooCustomRecoveryStore.class, BarCustomRecoveryStore.class))
         );
-        if (JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0) {
-            assertThat(e.getMessage(), containsString("Duplicate key recovery-type"));
-        } else {
-            assertThat(
-                e,
-                hasToString(
-                    matches(
-                        "java.lang.IllegalStateException: Duplicate key "
-                            + "org.opensearch.plugins.IndexStorePluginTests\\$RecoveryFactory@[\\w\\d]+"
-                    )
-                )
-            );
-        }
+        assertThat(e.getMessage(), containsString("Duplicate key recovery-type"));
     }
 }
diff --git a/server/src/test/java/org/opensearch/plugins/PluginInfoTests.java b/server/src/test/java/org/opensearch/plugins/PluginInfoTests.java
index c81e0d3d4cfea..0fe0ff5778c98 100644
--- a/server/src/test/java/org/opensearch/plugins/PluginInfoTests.java
+++ b/server/src/test/java/org/opensearch/plugins/PluginInfoTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.info.PluginsAndModules;
-import org.opensearch.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.ByteBufferStreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.nio.ByteBuffer;
@@ -46,8 +46,8 @@
 import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.contains;
-import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
 
 public class PluginInfoTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/plugins/PluginsServiceTests.java b/server/src/test/java/org/opensearch/plugins/PluginsServiceTests.java
index e022e78e7424b..5bb00833bcf99 100644
--- a/server/src/test/java/org/opensearch/plugins/PluginsServiceTests.java
+++ b/server/src/test/java/org/opensearch/plugins/PluginsServiceTests.java
@@ -34,8 +34,8 @@
 
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
-import org.apache.lucene.util.Constants;
 import org.apache.lucene.tests.util.LuceneTestCase;
+import org.apache.lucene.util.Constants;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.bootstrap.JarHell;
@@ -723,7 +723,7 @@ public void testIncompatibleJavaVersion() throws Exception {
             "desc",
             "1.0",
             Version.CURRENT,
-            "1000000.0",
+            "1000000",
             "FakePlugin",
             Collections.emptyList(),
             false
@@ -922,10 +922,9 @@ public void testNoExtensionConstructors() {
         class TestExtension implements TestExtensionPoint {
             private TestExtension() {}
         }
-        IllegalStateException e = expectThrows(
-            IllegalStateException.class,
-            () -> { PluginsService.createExtension(TestExtension.class, TestExtensionPoint.class, plugin); }
-        );
+        IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
+            PluginsService.createExtension(TestExtension.class, TestExtensionPoint.class, plugin);
+        });
 
         assertThat(
             e,
@@ -950,10 +949,9 @@ public TestExtension(TestPlugin plugin) {
 
             }
         }
-        IllegalStateException e = expectThrows(
-            IllegalStateException.class,
-            () -> { PluginsService.createExtension(TestExtension.class, TestExtensionPoint.class, plugin); }
-        );
+        IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
+            PluginsService.createExtension(TestExtension.class, TestExtensionPoint.class, plugin);
+        });
 
         assertThat(
             e,
@@ -971,10 +969,9 @@ public TestExtension(TestPlugin plugin) {
 
     public void testBadSingleParameterConstructor() {
         TestPlugin plugin = new TestPlugin();
-        IllegalStateException e = expectThrows(
-            IllegalStateException.class,
-            () -> { PluginsService.createExtension(BadSingleParameterConstructorExtension.class, TestExtensionPoint.class, plugin); }
-        );
+        IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
+            PluginsService.createExtension(BadSingleParameterConstructorExtension.class, TestExtensionPoint.class, plugin);
+        });
 
         assertThat(
             e,
@@ -996,10 +993,9 @@ public void testBadSingleParameterConstructor() {
 
     public void testTooManyParametersExtensionConstructors() {
         TestPlugin plugin = new TestPlugin();
-        IllegalStateException e = expectThrows(
-            IllegalStateException.class,
-            () -> { PluginsService.createExtension(TooManyParametersConstructorExtension.class, TestExtensionPoint.class, plugin); }
-        );
+        IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
+            PluginsService.createExtension(TooManyParametersConstructorExtension.class, TestExtensionPoint.class, plugin);
+        });
 
         assertThat(
             e,
@@ -1019,10 +1015,9 @@ public void testTooManyParametersExtensionConstructors() {
 
     public void testThrowingConstructor() {
         TestPlugin plugin = new TestPlugin();
-        IllegalStateException e = expectThrows(
-            IllegalStateException.class,
-            () -> { PluginsService.createExtension(ThrowingConstructorExtension.class, TestExtensionPoint.class, plugin); }
-        );
+        IllegalStateException e = expectThrows(IllegalStateException.class, () -> {
+            PluginsService.createExtension(ThrowingConstructorExtension.class, TestExtensionPoint.class, plugin);
+        });
 
         assertThat(
             e,
diff --git a/server/src/test/java/org/opensearch/plugins/spi/NamedXContentProviderTests.java b/server/src/test/java/org/opensearch/plugins/spi/NamedXContentProviderTests.java
index b90336730476b..32f155edbe54a 100644
--- a/server/src/test/java/org/opensearch/plugins/spi/NamedXContentProviderTests.java
+++ b/server/src/test/java/org/opensearch/plugins/spi/NamedXContentProviderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.plugins.spi;
 
-import org.opensearch.common.ParseField;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.pipeline.ParsedSimpleValue;
 import org.opensearch.search.suggest.Suggest;
diff --git a/server/src/test/java/org/opensearch/recovery/RecoveriesCollectionTests.java b/server/src/test/java/org/opensearch/recovery/RecoveriesCollectionTests.java
deleted file mode 100644
index 6a08f5115d1e2..0000000000000
--- a/server/src/test/java/org/opensearch/recovery/RecoveriesCollectionTests.java
+++ /dev/null
@@ -1,188 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.recovery;
-
-import org.opensearch.OpenSearchException;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
-import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.store.Store;
-import org.opensearch.indices.recovery.RecoveriesCollection;
-import org.opensearch.indices.recovery.RecoveryFailedException;
-import org.opensearch.indices.recovery.RecoveryState;
-import org.opensearch.indices.recovery.PeerRecoveryTargetService;
-import org.opensearch.indices.recovery.RecoveryTarget;
-
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.lessThan;
-
-public class RecoveriesCollectionTests extends OpenSearchIndexLevelReplicationTestCase {
-    static final PeerRecoveryTargetService.RecoveryListener listener = new PeerRecoveryTargetService.RecoveryListener() {
-        @Override
-        public void onRecoveryDone(RecoveryState state) {
-
-        }
-
-        @Override
-        public void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure) {
-
-        }
-    };
-
-    public void testLastAccessTimeUpdate() throws Exception {
-        try (ReplicationGroup shards = createGroup(0)) {
-            final RecoveriesCollection collection = new RecoveriesCollection(logger, threadPool);
-            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
-            try (RecoveriesCollection.RecoveryRef status = collection.getRecovery(recoveryId)) {
-                final long lastSeenTime = status.get().lastAccessTime();
-                assertBusy(() -> {
-                    try (RecoveriesCollection.RecoveryRef currentStatus = collection.getRecovery(recoveryId)) {
-                        assertThat("access time failed to update", lastSeenTime, lessThan(currentStatus.get().lastAccessTime()));
-                    }
-                });
-            } finally {
-                collection.cancelRecovery(recoveryId, "life");
-            }
-        }
-    }
-
-    public void testRecoveryTimeout() throws Exception {
-        try (ReplicationGroup shards = createGroup(0)) {
-            final RecoveriesCollection collection = new RecoveriesCollection(logger, threadPool);
-            final AtomicBoolean failed = new AtomicBoolean();
-            final CountDownLatch latch = new CountDownLatch(1);
-            final long recoveryId = startRecovery(
-                collection,
-                shards.getPrimaryNode(),
-                shards.addReplica(),
-                new PeerRecoveryTargetService.RecoveryListener() {
-                    @Override
-                    public void onRecoveryDone(RecoveryState state) {
-                        latch.countDown();
-                    }
-
-                    @Override
-                    public void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure) {
-                        failed.set(true);
-                        latch.countDown();
-                    }
-                },
-                TimeValue.timeValueMillis(100)
-            );
-            try {
-                latch.await(30, TimeUnit.SECONDS);
-                assertTrue("recovery failed to timeout", failed.get());
-            } finally {
-                collection.cancelRecovery(recoveryId, "meh");
-            }
-        }
-
-    }
-
-    public void testRecoveryCancellation() throws Exception {
-        try (ReplicationGroup shards = createGroup(0)) {
-            final RecoveriesCollection collection = new RecoveriesCollection(logger, threadPool);
-            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
-            final long recoveryId2 = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
-            try (RecoveriesCollection.RecoveryRef recoveryRef = collection.getRecovery(recoveryId)) {
-                ShardId shardId = recoveryRef.get().shardId();
-                assertTrue("failed to cancel recoveries", collection.cancelRecoveriesForShard(shardId, "test"));
-                assertThat("all recoveries should be cancelled", collection.size(), equalTo(0));
-            } finally {
-                collection.cancelRecovery(recoveryId, "meh");
-                collection.cancelRecovery(recoveryId2, "meh");
-            }
-        }
-    }
-
-    public void testResetRecovery() throws Exception {
-        try (ReplicationGroup shards = createGroup(0)) {
-            shards.startAll();
-            int numDocs = randomIntBetween(1, 15);
-            shards.indexDocs(numDocs);
-            final RecoveriesCollection collection = new RecoveriesCollection(logger, threadPool);
-            IndexShard shard = shards.addReplica();
-            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shard);
-            RecoveryTarget recoveryTarget = collection.getRecoveryTarget(recoveryId);
-            final int currentAsTarget = shard.recoveryStats().currentAsTarget();
-            final int referencesToStore = recoveryTarget.store().refCount();
-            IndexShard indexShard = recoveryTarget.indexShard();
-            Store store = recoveryTarget.store();
-            String tempFileName = recoveryTarget.getTempNameForFile("foobar");
-            RecoveryTarget resetRecovery = collection.resetRecovery(recoveryId, TimeValue.timeValueMinutes(60));
-            final long resetRecoveryId = resetRecovery.recoveryId();
-            assertNotSame(recoveryTarget, resetRecovery);
-            assertNotSame(recoveryTarget.cancellableThreads(), resetRecovery.cancellableThreads());
-            assertSame(indexShard, resetRecovery.indexShard());
-            assertSame(store, resetRecovery.store());
-            assertEquals(referencesToStore, resetRecovery.store().refCount());
-            assertEquals(currentAsTarget, shard.recoveryStats().currentAsTarget());
-            assertEquals(recoveryTarget.refCount(), 0);
-            expectThrows(OpenSearchException.class, () -> recoveryTarget.store());
-            expectThrows(OpenSearchException.class, () -> recoveryTarget.indexShard());
-            String resetTempFileName = resetRecovery.getTempNameForFile("foobar");
-            assertNotEquals(tempFileName, resetTempFileName);
-            assertEquals(currentAsTarget, shard.recoveryStats().currentAsTarget());
-            try (RecoveriesCollection.RecoveryRef newRecoveryRef = collection.getRecovery(resetRecoveryId)) {
-                shards.recoverReplica(shard, (s, n) -> {
-                    assertSame(s, newRecoveryRef.get().indexShard());
-                    return newRecoveryRef.get();
-                }, false);
-            }
-            shards.assertAllEqual(numDocs);
-            assertNull("recovery is done", collection.getRecovery(recoveryId));
-        }
-    }
-
-    long startRecovery(RecoveriesCollection collection, DiscoveryNode sourceNode, IndexShard shard) {
-        return startRecovery(collection, sourceNode, shard, listener, TimeValue.timeValueMinutes(60));
-    }
-
-    long startRecovery(
-        RecoveriesCollection collection,
-        DiscoveryNode sourceNode,
-        IndexShard indexShard,
-        PeerRecoveryTargetService.RecoveryListener listener,
-        TimeValue timeValue
-    ) {
-        final DiscoveryNode rNode = getDiscoveryNode(indexShard.routingEntry().currentNodeId());
-        indexShard.markAsRecovering("remote", new RecoveryState(indexShard.routingEntry(), sourceNode, rNode));
-        indexShard.prepareForIndexRecovery();
-        return collection.startRecovery(indexShard, sourceNode, listener, timeValue);
-    }
-}
diff --git a/server/src/test/java/org/opensearch/recovery/ReplicationCollectionTests.java b/server/src/test/java/org/opensearch/recovery/ReplicationCollectionTests.java
new file mode 100644
index 0000000000000..fb4dc97435512
--- /dev/null
+++ b/server/src/test/java/org/opensearch/recovery/ReplicationCollectionTests.java
@@ -0,0 +1,230 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.recovery;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.replication.OpenSearchIndexLevelReplicationTestCase;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.Store;
+import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.SegmentReplicationSource;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationTarget;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.lessThan;
+import static org.mockito.Mockito.mock;
+
+public class ReplicationCollectionTests extends OpenSearchIndexLevelReplicationTestCase {
+    static final ReplicationListener listener = new ReplicationListener() {
+        @Override
+        public void onDone(ReplicationState state) {
+
+        }
+
+        @Override
+        public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+
+        }
+    };
+
+    public void testLastAccessTimeUpdate() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            final ReplicationCollection<RecoveryTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
+            try (ReplicationCollection.ReplicationRef<RecoveryTarget> status = collection.get(recoveryId)) {
+                final long lastSeenTime = status.get().lastAccessTime();
+                assertBusy(() -> {
+                    try (ReplicationCollection.ReplicationRef<RecoveryTarget> currentStatus = collection.get(recoveryId)) {
+                        assertThat("access time failed to update", lastSeenTime, lessThan(currentStatus.get().lastAccessTime()));
+                    }
+                });
+            } finally {
+                collection.cancel(recoveryId, "life");
+            }
+        }
+    }
+
+    public void testRecoveryTimeout() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            final ReplicationCollection<RecoveryTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            final AtomicBoolean failed = new AtomicBoolean();
+            final CountDownLatch latch = new CountDownLatch(1);
+            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica(), new ReplicationListener() {
+                @Override
+                public void onDone(ReplicationState state) {
+                    latch.countDown();
+                }
+
+                @Override
+                public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                    failed.set(true);
+                    latch.countDown();
+                }
+            }, TimeValue.timeValueMillis(100));
+            try {
+                latch.await(30, TimeUnit.SECONDS);
+                assertTrue("recovery failed to timeout", failed.get());
+            } finally {
+                collection.cancel(recoveryId, "meh");
+            }
+        }
+    }
+
+    public void testStartMultipleReplicationsForSingleShard() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            shards.startAll();
+            final ReplicationCollection<ReplicationTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            final IndexShard shard = shards.addReplica();
+            shards.recoverReplica(shard);
+            final SegmentReplicationTarget target1 = new SegmentReplicationTarget(
+                shard,
+                shards.getPrimary().getLatestReplicationCheckpoint(),
+                mock(SegmentReplicationSource.class),
+                mock(ReplicationListener.class)
+            );
+            final SegmentReplicationTarget target2 = new SegmentReplicationTarget(
+                shard,
+                shards.getPrimary().getLatestReplicationCheckpoint(),
+                mock(SegmentReplicationSource.class),
+                mock(ReplicationListener.class)
+            );
+            collection.startSafe(target1, TimeValue.timeValueMinutes(30));
+            assertThrows(ReplicationFailedException.class, () -> collection.startSafe(target2, TimeValue.timeValueMinutes(30)));
+            target1.decRef();
+            target2.decRef();
+        }
+    }
+
+    public void testGetReplicationTargetMultiReplicationsForSingleShard() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            final ReplicationCollection<RecoveryTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            final IndexShard shard1 = shards.addReplica();
+            final IndexShard shard2 = shards.addReplica();
+            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shard1);
+            final long recoveryId2 = startRecovery(collection, shards.getPrimaryNode(), shard2);
+            try {
+                collection.getOngoingReplicationTarget(shard1.shardId());
+            } catch (AssertionError e) {
+                assertEquals(e.getMessage(), "More than one on-going replication targets");
+            } finally {
+                collection.cancel(recoveryId, "meh");
+                collection.cancel(recoveryId2, "meh");
+            }
+            closeShards(shard1, shard2);
+        }
+    }
+
+    public void testRecoveryCancellation() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            final ReplicationCollection<RecoveryTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
+            final long recoveryId2 = startRecovery(collection, shards.getPrimaryNode(), shards.addReplica());
+            try (ReplicationCollection.ReplicationRef<RecoveryTarget> recoveryRef = collection.get(recoveryId)) {
+                ShardId shardId = recoveryRef.get().indexShard().shardId();
+                assertTrue("failed to cancel recoveries", collection.cancelForShard(shardId, "test"));
+                assertThat("all recoveries should be cancelled", collection.size(), equalTo(0));
+            } finally {
+                collection.cancel(recoveryId, "meh");
+                collection.cancel(recoveryId2, "meh");
+            }
+        }
+    }
+
+    public void testResetRecovery() throws Exception {
+        try (ReplicationGroup shards = createGroup(0)) {
+            shards.startAll();
+            int numDocs = randomIntBetween(1, 15);
+            shards.indexDocs(numDocs);
+            final ReplicationCollection<RecoveryTarget> collection = new ReplicationCollection<>(logger, threadPool);
+            IndexShard shard = shards.addReplica();
+            final long recoveryId = startRecovery(collection, shards.getPrimaryNode(), shard);
+            RecoveryTarget recoveryTarget = collection.getTarget(recoveryId);
+            final int currentAsTarget = shard.recoveryStats().currentAsTarget();
+            final int referencesToStore = recoveryTarget.store().refCount();
+            IndexShard indexShard = recoveryTarget.indexShard();
+            Store store = recoveryTarget.store();
+            String tempFileName = recoveryTarget.getTempNameForFile("foobar");
+            RecoveryTarget resetRecovery = collection.reset(recoveryId, TimeValue.timeValueMinutes(60));
+            final long resetRecoveryId = resetRecovery.getId();
+            assertNotSame(recoveryTarget, resetRecovery);
+            assertNotSame(recoveryTarget.cancellableThreads(), resetRecovery.cancellableThreads());
+            assertSame(indexShard, resetRecovery.indexShard());
+            assertSame(store, resetRecovery.store());
+            assertEquals(referencesToStore, resetRecovery.store().refCount());
+            assertEquals(currentAsTarget, shard.recoveryStats().currentAsTarget());
+            assertEquals(recoveryTarget.refCount(), 0);
+            expectThrows(OpenSearchException.class, () -> recoveryTarget.store());
+            expectThrows(OpenSearchException.class, () -> recoveryTarget.indexShard());
+            String resetTempFileName = resetRecovery.getTempNameForFile("foobar");
+            assertNotEquals(tempFileName, resetTempFileName);
+            assertEquals(currentAsTarget, shard.recoveryStats().currentAsTarget());
+            try (ReplicationCollection.ReplicationRef<RecoveryTarget> newRecoveryRef = collection.get(resetRecoveryId)) {
+                shards.recoverReplica(shard, (s, n) -> {
+                    assertSame(s, newRecoveryRef.get().indexShard());
+                    return newRecoveryRef.get();
+                }, false);
+            }
+            shards.assertAllEqual(numDocs);
+            assertNull("recovery is done", collection.get(recoveryId));
+        }
+    }
+
+    long startRecovery(ReplicationCollection<RecoveryTarget> collection, DiscoveryNode sourceNode, IndexShard shard) {
+        return startRecovery(collection, sourceNode, shard, listener, TimeValue.timeValueMinutes(60));
+    }
+
+    long startRecovery(
+        ReplicationCollection<RecoveryTarget> collection,
+        DiscoveryNode sourceNode,
+        IndexShard indexShard,
+        ReplicationListener listener,
+        TimeValue timeValue
+    ) {
+        final DiscoveryNode rNode = getDiscoveryNode(indexShard.routingEntry().currentNodeId());
+        indexShard.markAsRecovering("remote", new RecoveryState(indexShard.routingEntry(), sourceNode, rNode));
+        indexShard.prepareForIndexRecovery();
+        return collection.start(new RecoveryTarget(indexShard, sourceNode, listener), timeValue);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/repositories/IndexIdTests.java b/server/src/test/java/org/opensearch/repositories/IndexIdTests.java
index 999459b3acbe9..2b927b3b40115 100644
--- a/server/src/test/java/org/opensearch/repositories/IndexIdTests.java
+++ b/server/src/test/java/org/opensearch/repositories/IndexIdTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.repositories;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/repositories/IndexMetadataGenerationsTests.java b/server/src/test/java/org/opensearch/repositories/IndexMetadataGenerationsTests.java
new file mode 100644
index 0000000000000..1e2d72e4a91fd
--- /dev/null
+++ b/server/src/test/java/org/opensearch/repositories/IndexMetadataGenerationsTests.java
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories;
+
+import org.opensearch.snapshots.SnapshotId;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class IndexMetadataGenerationsTests extends OpenSearchTestCase {
+
+    private final int MAX_TEST_INDICES = 10;
+    private final String SNAPSHOT = "snapshot";
+    private final String INDEX_PREFIX = "index-";
+    private final String BLOB_ID_PREFIX = "blob-";
+    private IndexMetaDataGenerations indexMetaDataGenerations;
+
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        final int numIndices = randomIntBetween(1, MAX_TEST_INDICES);
+        Map<IndexId, String> indexMap = createIndexMetadataMap(1, numIndices);
+        Map<String, String> identifierMap = createIdentifierMapFromIndexMetadata(indexMap, BLOB_ID_PREFIX);
+        Map<SnapshotId, Map<IndexId, String>> lookupMap = Collections.singletonMap(new SnapshotId(SNAPSHOT, SNAPSHOT), indexMap);
+        indexMetaDataGenerations = new IndexMetaDataGenerations(lookupMap, identifierMap);
+    }
+
+    public void testEmpty() {
+        assertTrue(IndexMetaDataGenerations.EMPTY.isEmpty());
+        assertNull(IndexMetaDataGenerations.EMPTY.getIndexMetaBlobId("test"));
+    }
+
+    public void testBaseCase() {
+        assertFalse(indexMetaDataGenerations.isEmpty());
+        assertEquals(BLOB_ID_PREFIX + 1, indexMetaDataGenerations.getIndexMetaBlobId(String.valueOf(1)));
+    }
+
+    public void testIndexMetaBlobId() {
+        SnapshotId snapshotId = new SnapshotId(SNAPSHOT, SNAPSHOT);
+        IndexId indexId = new IndexId(INDEX_PREFIX + 1, INDEX_PREFIX + 1);
+        assertEquals(BLOB_ID_PREFIX + 1, indexMetaDataGenerations.indexMetaBlobId(snapshotId, indexId));
+    }
+
+    public void testIndexMetaBlobIdFallback() {
+        SnapshotId snapshotId = new SnapshotId(SNAPSHOT, SNAPSHOT);
+        IndexId indexId = new IndexId("missingIndex", "missingIndex");
+        assertEquals(SNAPSHOT, indexMetaDataGenerations.indexMetaBlobId(snapshotId, indexId));
+
+        final String randomString = randomAlphaOfLength(8);
+        snapshotId = new SnapshotId(randomString, randomString);
+        assertEquals(randomString, indexMetaDataGenerations.indexMetaBlobId(snapshotId, indexId));
+    }
+
+    public void testWithAddedSnapshot() {
+        // Construct a new snapshot
+        SnapshotId newSnapshot = new SnapshotId("newSnapshot", "newSnapshot");
+        final String newIndexMetadataPrefix = "newIndexMetadata-";
+        final String newBlobIdPrefix = "newBlob-";
+        final int numIndices = randomIntBetween(2, MAX_TEST_INDICES);
+        Map<IndexId, String> newLookupMap = createIndexMetadataMap(2, numIndices);
+        Map<String, String> identifierMap = createIdentifierMapFromIndexMetadata(newLookupMap, "newBlob-");
+
+        // Add the snapshot and verify that values have been updated as expected
+        IndexMetaDataGenerations updated = indexMetaDataGenerations.withAddedSnapshot(newSnapshot, newLookupMap, identifierMap);
+        assertEquals(newBlobIdPrefix + 2, updated.getIndexMetaBlobId(String.valueOf(2)));
+        assertEquals(newBlobIdPrefix + 2, updated.indexMetaBlobId(newSnapshot, new IndexId(INDEX_PREFIX + 2, INDEX_PREFIX + 2)));
+        // The first index should remain unchanged
+        assertEquals(BLOB_ID_PREFIX + 1, updated.getIndexMetaBlobId(String.valueOf(1)));
+    }
+
+    public void testWithRemovedSnapshot() {
+        Set<SnapshotId> snapshotToRemove = Collections.singleton(new SnapshotId(SNAPSHOT, SNAPSHOT));
+        assertEquals(IndexMetaDataGenerations.EMPTY, indexMetaDataGenerations.withRemovedSnapshots(snapshotToRemove));
+    }
+
+    private Map<IndexId, String> createIndexMetadataMap(int indexCountLowerBound, int numIndices) {
+        final int indexCountUpperBound = indexCountLowerBound + numIndices;
+        Map<IndexId, String> map = new HashMap<>();
+        for (int i = indexCountLowerBound; i <= indexCountUpperBound; i++) {
+            map.put(new IndexId(INDEX_PREFIX + i, INDEX_PREFIX + i), String.valueOf(i));
+        }
+        return map;
+    }
+
+    private Map<String, String> createIdentifierMapFromIndexMetadata(Map<IndexId, String> indexMetadataMap, String blobIdPrefix) {
+        return indexMetadataMap.values().stream().collect(Collectors.toMap(k -> k, v -> blobIdPrefix + v));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/repositories/RepositoriesModuleTests.java b/server/src/test/java/org/opensearch/repositories/RepositoriesModuleTests.java
index 4362e9600d237..21ca81bb5df92 100644
--- a/server/src/test/java/org/opensearch/repositories/RepositoriesModuleTests.java
+++ b/server/src/test/java/org/opensearch/repositories/RepositoriesModuleTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.RepositoryPlugin;
diff --git a/server/src/test/java/org/opensearch/repositories/RepositoriesServiceTests.java b/server/src/test/java/org/opensearch/repositories/RepositoriesServiceTests.java
index 6a8999a205be2..9475dba128e97 100644
--- a/server/src/test/java/org/opensearch/repositories/RepositoriesServiceTests.java
+++ b/server/src/test/java/org/opensearch/repositories/RepositoriesServiceTests.java
@@ -34,59 +34,90 @@
 
 import org.apache.lucene.index.IndexCommit;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.admin.cluster.crypto.CryptoSettings;
 import org.opensearch.action.admin.cluster.repositories.put.PutRepositoryRequest;
+import org.opensearch.cluster.AckedClusterStateUpdateTask;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.ack.ClusterStateUpdateResponse;
+import org.opensearch.cluster.metadata.CryptoMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterApplierService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.crypto.CryptoHandler;
+import org.opensearch.common.crypto.DecryptedRangedStreamProvider;
+import org.opensearch.common.crypto.EncryptedHeaderContentSupplier;
+import org.opensearch.common.crypto.MasterKeyProvider;
+import org.opensearch.common.io.InputStreamContainer;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleListener;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.plugins.CryptoPlugin;
 import org.opensearch.repositories.blobstore.MeteredBlobStoreRepository;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportService;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.SYSTEM_REPOSITORY_SETTING;
 import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 public class RepositoriesServiceTests extends OpenSearchTestCase {
 
     private RepositoriesService repositoriesService;
+    private final String kpTypeA = "kp-type-a";
+    private final String kpTypeB = "kp-type-b";
 
     @Override
     public void setUp() throws Exception {
         super.setUp();
+        ThreadPool threadPool = mock(ThreadPool.class);
+        final ClusterApplierService clusterApplierService = mock(ClusterApplierService.class);
+        when(clusterApplierService.threadPool()).thenReturn(threadPool);
+        final ClusterService clusterService = mock(ClusterService.class);
+        repositoriesService = createRepositoriesServiceWithMockedClusterService(clusterService);
+    }
+
+    private RepositoriesService createRepositoriesServiceWithMockedClusterService(ClusterService clusterService) {
         ThreadPool threadPool = mock(ThreadPool.class);
         final TransportService transportService = new TransportService(
             Settings.EMPTY,
@@ -95,13 +126,13 @@ public void setUp() throws Exception {
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             boundAddress -> DiscoveryNode.createLocal(Settings.EMPTY, boundAddress.publishAddress(), UUIDs.randomBase64UUID()),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         final ClusterApplierService clusterApplierService = mock(ClusterApplierService.class);
         when(clusterApplierService.threadPool()).thenReturn(threadPool);
-        final ClusterService clusterService = mock(ClusterService.class);
         when(clusterService.getClusterApplierService()).thenReturn(clusterApplierService);
-        Map<String, Repository.Factory> typesRegistry = org.opensearch.common.collect.Map.of(
+        Map<String, Repository.Factory> typesRegistry = Map.of(
             TestRepository.TYPE,
             TestRepository::new,
             MeteredRepositoryTypeA.TYPE,
@@ -109,15 +140,24 @@ public void setUp() throws Exception {
             MeteredRepositoryTypeB.TYPE,
             metadata -> new MeteredRepositoryTypeB(metadata, clusterService)
         );
-        repositoriesService = new RepositoriesService(
+
+        DiscoveryNodes nodes = mock(DiscoveryNodes.class);
+        when(nodes.getMinNodeVersion()).thenReturn(Version.V_2_9_0);
+        ClusterState currentClusterState = mock(ClusterState.class);
+        when(currentClusterState.getNodes()).thenReturn(nodes);
+        when(clusterService.state()).thenReturn(currentClusterState);
+
+        RepositoriesService repositoriesService = new RepositoriesService(
             Settings.EMPTY,
-            mock(ClusterService.class),
+            clusterService,
             transportService,
             typesRegistry,
             typesRegistry,
             threadPool
         );
+
         repositoriesService.start();
+        return repositoriesService;
     }
 
     public void testRegisterInternalRepository() {
@@ -162,6 +202,13 @@ public void testRegisterRejectsInvalidRepositoryNames() {
         }
     }
 
+    public void testUpdateOrRegisterRejectsForSystemRepository() {
+        String repoName = "name";
+        PutRepositoryRequest request = new PutRepositoryRequest(repoName);
+        request.settings(Settings.builder().put(SYSTEM_REPOSITORY_SETTING.getKey(), true).build());
+        expectThrows(RepositoryException.class, () -> repositoriesService.registerOrUpdateRepository(request, null));
+    }
+
     public void testRepositoriesStatsCanHaveTheSameNameAndDifferentTypeOverTime() {
         String repoName = "name";
         expectThrows(RepositoryMissingException.class, () -> repositoriesService.repository(repoName));
@@ -188,6 +235,254 @@ public void testRepositoriesStatsCanHaveTheSameNameAndDifferentTypeOverTime() {
         assertThat(repositoryStatsTypeB.getRepositoryStats(), equalTo(MeteredRepositoryTypeB.STATS));
     }
 
+    public void testWithSameKeyProviderNames() {
+        String keyProviderName = "kp-name";
+        ClusterState clusterStateWithRepoTypeA = createClusterStateWithKeyProvider(
+            "repoName",
+            MeteredRepositoryTypeA.TYPE,
+            keyProviderName,
+            kpTypeA
+        );
+
+        repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeA, emptyState()));
+        assertThat(repositoriesService.repositoriesStats().size(), equalTo(1));
+        MeteredRepositoryTypeA repository = (MeteredRepositoryTypeA) repositoriesService.repository("repoName");
+        assertNotNull(repository);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+
+        ClusterState clusterStateWithRepoTypeB = createClusterStateWithKeyProvider(
+            "repoName",
+            MeteredRepositoryTypeB.TYPE,
+            keyProviderName,
+            kpTypeA
+        );
+        repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeB, emptyState()));
+        assertThat(repositoriesService.repositoriesStats().size(), equalTo(2));
+        MeteredRepositoryTypeB repositoryB = (MeteredRepositoryTypeB) repositoriesService.repository("repoName");
+        assertNotNull(repositoryB);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+    }
+
+    public void testCryptoManagersUnchangedWithSameCryptoMetadata() {
+        String keyProviderName = "kp-name";
+        ClusterState clusterStateWithRepoTypeA = createClusterStateWithKeyProvider(
+            "repoName",
+            MeteredRepositoryTypeA.TYPE,
+            keyProviderName,
+            kpTypeA
+        );
+        repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeA, emptyState()));
+        assertThat(repositoriesService.repositoriesStats().size(), equalTo(1));
+        MeteredRepositoryTypeA repository = (MeteredRepositoryTypeA) repositoriesService.repository("repoName");
+        assertNotNull(repository);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+
+        repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeA, emptyState()));
+        assertThat(repositoriesService.repositoriesStats().size(), equalTo(1));
+        repository = (MeteredRepositoryTypeA) repositoriesService.repository("repoName");
+        assertNotNull(repository);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+    }
+
+    public void testRepositoryUpdateWithDifferentCryptoMetadata() {
+        String keyProviderName = "kp-name";
+
+        ClusterState clusterStateWithRepoTypeA = createClusterStateWithKeyProvider(
+            "repoName",
+            MeteredRepositoryTypeA.TYPE,
+            keyProviderName,
+            kpTypeA
+        );
+        ClusterService clusterService = mock(ClusterService.class);
+
+        PutRepositoryRequest request = new PutRepositoryRequest("repoName");
+        request.type(MeteredRepositoryTypeA.TYPE);
+        request.settings(Settings.EMPTY);
+
+        doAnswer((invocation) -> {
+            AckedClusterStateUpdateTask<ClusterStateUpdateResponse> task = (AckedClusterStateUpdateTask<
+                ClusterStateUpdateResponse>) invocation.getArguments()[1];
+            task.execute(clusterStateWithRepoTypeA);
+            return null;
+        }).when(clusterService).submitStateUpdateTask(any(), any());
+
+        RepositoriesService repositoriesService = createRepositoriesServiceWithMockedClusterService(clusterService);
+        repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeA, emptyState()));
+        assertThat(repositoriesService.repositoriesStats().size(), equalTo(1));
+        MeteredRepositoryTypeA repository = (MeteredRepositoryTypeA) repositoriesService.repository("repoName");
+        assertNotNull(repository);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+
+        expectThrows(IllegalArgumentException.class, () -> repositoriesService.registerOrUpdateRepository(request, null));
+
+        CryptoSettings cryptoSettings = new CryptoSettings(keyProviderName);
+        cryptoSettings.keyProviderType(kpTypeA);
+        cryptoSettings.settings(Settings.builder().put("key-1", "val-1"));
+        request.cryptoSettings(cryptoSettings);
+        expectThrows(IllegalArgumentException.class, () -> repositoriesService.registerOrUpdateRepository(request, null));
+
+        cryptoSettings.settings(Settings.builder());
+        cryptoSettings.keyProviderName("random");
+        expectThrows(IllegalArgumentException.class, () -> repositoriesService.registerOrUpdateRepository(request, null));
+
+        cryptoSettings.keyProviderName(keyProviderName);
+
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+        repositoriesService.registerOrUpdateRepository(request, null);
+    }
+
+    public void testCryptoManagerClusterStateChanges() {
+
+        ClusterService clusterService = mock(ClusterService.class);
+        AtomicBoolean verified = new AtomicBoolean();
+        List<RepositoryMetadata> repositoryMetadata = new ArrayList<>();
+
+        String keyProviderName = "kp-name-1";
+        String repoName = "repoName";
+        String keyProviderType = kpTypeA;
+        Settings.Builder settings = Settings.builder();
+        PutRepositoryRequest request = createPutRepositoryEncryptedRequest(
+            repoName,
+            MeteredRepositoryTypeA.TYPE,
+            keyProviderName,
+            settings,
+            keyProviderType
+        );
+        verified.set(false);
+        RepositoriesService repositoriesService = createRepositoriesServiceAndMockCryptoClusterState(
+            clusterService,
+            repoName,
+            keyProviderName,
+            keyProviderType,
+            settings.build(),
+            verified,
+            repositoryMetadata
+        );
+        repositoriesService.registerOrUpdateRepository(request, null);
+        MeteredRepositoryTypeA repository = (MeteredRepositoryTypeA) repositoriesService.repository(repoName);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+        assertTrue(verified.get());
+
+        // No change
+        keyProviderType = kpTypeA;
+        settings = Settings.builder();
+        request = createPutRepositoryEncryptedRequest(repoName, MeteredRepositoryTypeA.TYPE, keyProviderName, settings, keyProviderType);
+        verified.set(false);
+        repositoriesService = createRepositoriesServiceAndMockCryptoClusterState(
+            clusterService,
+            repoName,
+            keyProviderName,
+            keyProviderType,
+            settings.build(),
+            verified,
+            repositoryMetadata
+        );
+        repositoriesService.registerOrUpdateRepository(request, null);
+
+        repository = (MeteredRepositoryTypeA) repositoriesService.repository(repoName);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+        assertTrue(verified.get());
+
+        // Same crypto client in new repo
+        repoName = "repoName-2";
+        keyProviderType = kpTypeA;
+        settings = Settings.builder();
+        request = createPutRepositoryEncryptedRequest(repoName, MeteredRepositoryTypeA.TYPE, keyProviderName, settings, keyProviderType);
+        verified.set(false);
+        repositoriesService = createRepositoriesServiceAndMockCryptoClusterState(
+            clusterService,
+            repoName,
+            keyProviderName,
+            keyProviderType,
+            settings.build(),
+            verified,
+            repositoryMetadata
+        );
+        repositoriesService.registerOrUpdateRepository(request, null);
+        repository = (MeteredRepositoryTypeA) repositoriesService.repository(repoName);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeA, repository.cryptoHandler.kpType);
+        assertTrue(verified.get());
+
+        // Different crypto client in new repo
+        repoName = "repoName-3";
+        keyProviderType = kpTypeB;
+        settings = Settings.builder();
+        request = createPutRepositoryEncryptedRequest(repoName, MeteredRepositoryTypeA.TYPE, keyProviderName, settings, keyProviderType);
+        verified.set(false);
+        repositoriesService = createRepositoriesServiceAndMockCryptoClusterState(
+            clusterService,
+            repoName,
+            keyProviderName,
+            keyProviderType,
+            settings.build(),
+            verified,
+            repositoryMetadata
+        );
+        repositoriesService.registerOrUpdateRepository(request, null);
+        repository = (MeteredRepositoryTypeA) repositoriesService.repository(repoName);
+        assertNotNull(repository.cryptoHandler);
+        assertEquals(kpTypeB, repository.cryptoHandler.kpType);
+        assertTrue(verified.get());
+
+    }
+
+    private RepositoriesService createRepositoriesServiceAndMockCryptoClusterState(
+        ClusterService clusterService,
+        String repoName,
+        String keyProviderName,
+        String keyProviderType,
+        Settings settings,
+        AtomicBoolean verified,
+        List<RepositoryMetadata> repositoryMetadataList
+    ) {
+
+        ClusterState.Builder state = ClusterState.builder(new ClusterName("test"));
+        CryptoMetadata newCryptoMetadata = new CryptoMetadata(keyProviderName, keyProviderType, Settings.EMPTY);
+        Metadata.Builder mdBuilder = Metadata.builder();
+
+        RepositoryMetadata newRepositoryMetadata = new RepositoryMetadata(
+            repoName,
+            MeteredRepositoryTypeA.TYPE,
+            Settings.EMPTY,
+            newCryptoMetadata
+        );
+        if (!repositoryMetadataList.contains(newRepositoryMetadata)) {
+            repositoryMetadataList.add(newRepositoryMetadata);
+        }
+        RepositoriesMetadata newRepositoriesMetadata = new RepositoriesMetadata(repositoryMetadataList);
+        mdBuilder.putCustom(RepositoriesMetadata.TYPE, newRepositoriesMetadata);
+        state.metadata(mdBuilder);
+        ClusterState clusterStateWithRepoTypeA = state.build();
+
+        RepositoriesService repositoriesService = createRepositoriesServiceWithMockedClusterService(clusterService);
+
+        doAnswer((invocation) -> {
+            AckedClusterStateUpdateTask<ClusterStateUpdateResponse> task = (AckedClusterStateUpdateTask<
+                ClusterStateUpdateResponse>) invocation.getArguments()[1];
+            ClusterState clusterState = task.execute(clusterStateWithRepoTypeA);
+            RepositoriesMetadata repositories = clusterState.metadata().custom(RepositoriesMetadata.TYPE);
+            RepositoryMetadata repositoryMetadata = repositories.repositories().get(repositoryMetadataList.size() - 1);
+            CryptoMetadata cryptoMetadata = repositoryMetadata.cryptoMetadata();
+            assertNotNull(cryptoMetadata);
+            assertEquals(keyProviderName, cryptoMetadata.keyProviderName());
+            assertEquals(keyProviderType, cryptoMetadata.keyProviderType());
+            assertEquals(cryptoMetadata.settings(), settings);
+            verified.set(true);
+            repositoriesService.applyClusterState(new ClusterChangedEvent("new repo", clusterStateWithRepoTypeA, emptyState()));
+            return null;
+        }).when(clusterService).submitStateUpdateTask(any(), any());
+
+        return repositoriesService;
+    }
+
     private ClusterState createClusterStateWithRepo(String repoName, String repoType) {
         ClusterState.Builder state = ClusterState.builder(new ClusterName("test"));
         Metadata.Builder mdBuilder = Metadata.builder();
@@ -200,13 +495,136 @@ private ClusterState createClusterStateWithRepo(String repoName, String repoType
         return state.build();
     }
 
+    private ClusterState createClusterStateWithKeyProvider(
+        String repoName,
+        String repoType,
+        String keyProviderName,
+        String keyProviderType
+    ) {
+        ClusterState.Builder state = ClusterState.builder(new ClusterName("test"));
+        Metadata.Builder mdBuilder = Metadata.builder();
+        CryptoMetadata cryptoMetadata = new CryptoMetadata(keyProviderName, keyProviderType, Settings.EMPTY);
+        mdBuilder.putCustom(
+            RepositoriesMetadata.TYPE,
+            new RepositoriesMetadata(Collections.singletonList(new RepositoryMetadata(repoName, repoType, Settings.EMPTY, cryptoMetadata)))
+        );
+        state.metadata(mdBuilder);
+
+        return state.build();
+    }
+
+    private PutRepositoryRequest createPutRepositoryEncryptedRequest(
+        String repoName,
+        String repoType,
+        String keyProviderName,
+        Settings.Builder settings,
+        String keyProviderType
+    ) {
+        PutRepositoryRequest repositoryRequest = new PutRepositoryRequest(repoName);
+        repositoryRequest.type(repoType);
+        repositoryRequest.settings(Settings.EMPTY);
+        CryptoSettings cryptoSettings = new CryptoSettings(keyProviderName);
+        cryptoSettings.keyProviderName(keyProviderName);
+        cryptoSettings.keyProviderType(keyProviderType);
+        cryptoSettings.settings(settings);
+        repositoryRequest.cryptoSettings(cryptoSettings);
+
+        return repositoryRequest;
+    }
+
     private ClusterState emptyState() {
         return ClusterState.builder(new ClusterName("test")).build();
     }
 
     private void assertThrowsOnRegister(String repoName) {
         PutRepositoryRequest request = new PutRepositoryRequest(repoName);
-        expectThrows(RepositoryException.class, () -> repositoriesService.registerRepository(request, null));
+        expectThrows(RepositoryException.class, () -> repositoriesService.registerOrUpdateRepository(request, null));
+    }
+
+    private static class TestCryptoProvider implements CryptoHandler<Object, Object> {
+        final String kpName;
+        final String kpType;
+
+        public TestCryptoProvider(String kpName, String kpType) {
+            this.kpName = kpName;
+            this.kpType = kpType;
+        }
+
+        @Override
+        public Object initEncryptionMetadata() {
+            return new Object();
+        }
+
+        @Override
+        public long adjustContentSizeForPartialEncryption(Object cryptoContextObj, long contentSize) {
+            return 0;
+        }
+
+        @Override
+        public long estimateEncryptedLengthOfEntireContent(Object cryptoContextObj, long contentLength) {
+            return 0;
+        }
+
+        @Override
+        public InputStreamContainer createEncryptingStream(Object encryptionMetadata, InputStreamContainer streamContainer) {
+            return null;
+        }
+
+        @Override
+        public InputStreamContainer createEncryptingStreamOfPart(
+            Object cryptoContextObj,
+            InputStreamContainer stream,
+            int totalStreams,
+            int streamIdx
+        ) {
+            return null;
+        }
+
+        @Override
+        public InputStream createDecryptingStream(InputStream encryptingStream) {
+            return null;
+        }
+
+        @Override
+        public Object loadEncryptionMetadata(EncryptedHeaderContentSupplier encryptedHeaderContentSupplier) throws IOException {
+            return null;
+        }
+
+        @Override
+        public DecryptedRangedStreamProvider createDecryptingStreamOfRange(
+            Object cryptoContext,
+            long startPosOfRawContent,
+            long endPosOfRawContent
+        ) {
+            return null;
+        }
+
+        @Override
+        public long estimateDecryptedLength(Object cryptoContext, long contentLength) {
+            return 0;
+        }
+
+        @Override
+        public void close() throws IOException {
+
+        }
+    }
+
+    private static abstract class TestCryptoHandler implements CryptoPlugin<Object, Object> {
+        private final Settings settings;
+
+        public TestCryptoHandler(Settings settings) {
+            this.settings = settings;
+        }
+
+        public CryptoHandler<Object, Object> getOrCreateCryptoHandler(
+            MasterKeyProvider keyProvider,
+            String keyProviderName,
+            String keyProviderType,
+            Runnable onClose
+        ) {
+            return new TestCryptoProvider(keyProviderName, keyProviderType);
+        }
     }
 
     private static class TestRepository implements Repository {
@@ -284,6 +702,16 @@ public long getRestoreThrottleTimeInNanos() {
             return 0;
         }
 
+        @Override
+        public long getRemoteUploadThrottleTimeInNanos() {
+            return 0;
+        }
+
+        @Override
+        public long getRemoteDownloadThrottleTimeInNanos() {
+            return 0;
+        }
+
         @Override
         public String startVerification() {
             return null;
@@ -304,6 +732,11 @@ public boolean isReadOnly() {
             return false;
         }
 
+        @Override
+        public boolean isSystemRepository() {
+            return false;
+        }
+
         @Override
         public void snapshotShard(
             Store store,
@@ -320,6 +753,21 @@ public void snapshotShard(
 
         }
 
+        @Override
+        public void snapshotRemoteStoreIndexShard(
+            Store store,
+            SnapshotId snapshotId,
+            IndexId indexId,
+            IndexCommit snapshotIndexCommit,
+            String shardStateIdentifier,
+            IndexShardSnapshotStatus snapshotStatus,
+            long primaryTerm,
+            long startTime,
+            ActionListener<String> listener
+        ) {
+
+        }
+
         @Override
         public void restoreShard(
             Store store,
@@ -332,6 +780,15 @@ public void restoreShard(
 
         }
 
+        @Override
+        public RemoteStoreShardShallowCopySnapshot getRemoteStoreShallowCopyShardMetadata(
+            SnapshotId snapshotId,
+            IndexId indexId,
+            ShardId snapshotShardId
+        ) {
+            return null;
+        }
+
         @Override
         public IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, IndexId indexId, ShardId shardId) {
             return null;
@@ -358,6 +815,18 @@ public void cloneShardSnapshot(
 
         }
 
+        @Override
+        public void cloneRemoteStoreIndexShardSnapshot(
+            SnapshotId source,
+            SnapshotId target,
+            RepositoryShardId shardId,
+            String shardGeneration,
+            RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+            ActionListener<String> listener
+        ) {
+
+        }
+
         @Override
         public Lifecycle.State lifecycleState() {
             return null;
@@ -391,17 +860,20 @@ public void close() {
 
     private static class MeteredRepositoryTypeA extends MeteredBlobStoreRepository {
         private static final String TYPE = "type-a";
-        private static final RepositoryStats STATS = new RepositoryStats(org.opensearch.common.collect.Map.of("GET", 10L));
+        private static final RepositoryStats STATS = new RepositoryStats(Map.of("GET", 10L));
+        private final TestCryptoProvider cryptoHandler;
 
         private MeteredRepositoryTypeA(RepositoryMetadata metadata, ClusterService clusterService) {
-            super(
-                metadata,
-                false,
-                mock(NamedXContentRegistry.class),
-                clusterService,
-                mock(RecoverySettings.class),
-                org.opensearch.common.collect.Map.of("bucket", "bucket-a")
-            );
+            super(metadata, mock(NamedXContentRegistry.class), clusterService, mock(RecoverySettings.class), Map.of("bucket", "bucket-a"));
+
+            if (metadata.cryptoMetadata() != null) {
+                cryptoHandler = new TestCryptoProvider(
+                    metadata.cryptoMetadata().keyProviderName(),
+                    metadata.cryptoMetadata().keyProviderType()
+                );
+            } else {
+                cryptoHandler = null;
+            }
         }
 
         @Override
@@ -422,17 +894,20 @@ public BlobPath basePath() {
 
     private static class MeteredRepositoryTypeB extends MeteredBlobStoreRepository {
         private static final String TYPE = "type-b";
-        private static final RepositoryStats STATS = new RepositoryStats(org.opensearch.common.collect.Map.of("LIST", 20L));
+        private static final RepositoryStats STATS = new RepositoryStats(Map.of("LIST", 20L));
+        private final TestCryptoProvider cryptoHandler;
 
         private MeteredRepositoryTypeB(RepositoryMetadata metadata, ClusterService clusterService) {
-            super(
-                metadata,
-                false,
-                mock(NamedXContentRegistry.class),
-                clusterService,
-                mock(RecoverySettings.class),
-                org.opensearch.common.collect.Map.of("bucket", "bucket-b")
-            );
+            super(metadata, mock(NamedXContentRegistry.class), clusterService, mock(RecoverySettings.class), Map.of("bucket", "bucket-b"));
+
+            if (metadata.cryptoMetadata() != null) {
+                cryptoHandler = new TestCryptoProvider(
+                    metadata.cryptoMetadata().keyProviderName(),
+                    metadata.cryptoMetadata().keyProviderType()
+                );
+            } else {
+                cryptoHandler = null;
+            }
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/repositories/RepositoriesStatsArchiveTests.java b/server/src/test/java/org/opensearch/repositories/RepositoriesStatsArchiveTests.java
index 4ad3e1ef85f70..cf0b06a3f7d16 100644
--- a/server/src/test/java/org/opensearch/repositories/RepositoriesStatsArchiveTests.java
+++ b/server/src/test/java/org/opensearch/repositories/RepositoriesStatsArchiveTests.java
@@ -37,6 +37,7 @@
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -60,19 +61,14 @@ public void testStatsAreEvictedOnceTheyAreOlderThanRetentionPeriod() {
         fakeRelativeClock.set(retentionTimeInMillis * 2);
         int statsToBeRetainedCount = randomInt(10);
         for (int i = 0; i < statsToBeRetainedCount; i++) {
-            RepositoryStatsSnapshot repoStats = createRepositoryStats(
-                new RepositoryStats(org.opensearch.common.collect.Map.of("GET", 10L))
-            );
+            RepositoryStatsSnapshot repoStats = createRepositoryStats(new RepositoryStats(Map.of("GET", 10L)));
             repositoriesStatsArchive.archive(repoStats);
         }
 
         List<RepositoryStatsSnapshot> archivedStats = repositoriesStatsArchive.getArchivedStats();
         assertThat(archivedStats.size(), equalTo(statsToBeRetainedCount));
         for (RepositoryStatsSnapshot repositoryStatsSnapshot : archivedStats) {
-            assertThat(
-                repositoryStatsSnapshot.getRepositoryStats().requestCounts,
-                equalTo(org.opensearch.common.collect.Map.of("GET", 10L))
-            );
+            assertThat(repositoryStatsSnapshot.getRepositoryStats().requestCounts, equalTo(Map.of("GET", 10L)));
         }
     }
 
@@ -129,7 +125,7 @@ private RepositoryStatsSnapshot createRepositoryStats(RepositoryStats repository
             UUIDs.randomBase64UUID(),
             randomAlphaOfLength(10),
             randomAlphaOfLength(10),
-            org.opensearch.common.collect.Map.of("bucket", randomAlphaOfLength(10)),
+            Map.of("bucket", randomAlphaOfLength(10)),
             System.currentTimeMillis(),
             null
         );
diff --git a/server/src/test/java/org/opensearch/repositories/RepositoryDataTests.java b/server/src/test/java/org/opensearch/repositories/RepositoryDataTests.java
index 5c2080ca38424..a5bfca6892013 100644
--- a/server/src/test/java/org/opensearch/repositories/RepositoryDataTests.java
+++ b/server/src/test/java/org/opensearch/repositories/RepositoryDataTests.java
@@ -35,12 +35,13 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotState;
 import org.opensearch.test.OpenSearchTestCase;
@@ -296,7 +297,7 @@ public void testIndexThatReferencesAnUnknownSnapshot() throws IOException {
     }
 
     public void testIndexThatReferenceANullSnapshot() throws IOException {
-        final XContentBuilder builder = XContentBuilder.builder(randomFrom(XContentType.JSON).xContent());
+        final XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
         builder.startObject();
         {
             builder.startArray("snapshots");
diff --git a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryHelperTests.java b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryHelperTests.java
new file mode 100644
index 0000000000000..a24fd04d3d4f6
--- /dev/null
+++ b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryHelperTests.java
@@ -0,0 +1,140 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.blobstore;
+
+import org.opensearch.action.support.master.AcknowledgedResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.RepositoryPlugin;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class BlobStoreRepositoryHelperTests extends OpenSearchSingleNodeTestCase {
+
+    static final String REPO_TYPE = "fsLike";
+
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Arrays.asList(FsLikeRepoPlugin.class);
+    }
+
+    protected String[] getLockFilesInRemoteStore(String remoteStoreIndex, String remoteStoreRepository) throws IOException {
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(remoteStoreIndex)
+            .get()
+            .getSetting(remoteStoreIndex, IndexMetadata.SETTING_INDEX_UUID);
+        final RepositoriesService repositoriesService = getInstanceFromNode(RepositoriesService.class);
+        final BlobStoreRepository remoteStorerepository = (BlobStoreRepository) repositoriesService.repository(remoteStoreRepository);
+        BlobPath shardLevelBlobPath = remoteStorerepository.basePath().add(indexUUID).add("0").add("segments").add("lock_files");
+        BlobContainer blobContainer = remoteStorerepository.blobStore().blobContainer(shardLevelBlobPath);
+        try (RemoteBufferedOutputDirectory lockDirectory = new RemoteBufferedOutputDirectory(blobContainer)) {
+            return Arrays.stream(lockDirectory.listAll()).filter(lock -> lock.endsWith(".lock")).toArray(String[]::new);
+        }
+    }
+
+    // the reason for this plug-in is to drop any assertSnapshotOrGenericThread as mostly all access in this test goes from test threads
+    public static class FsLikeRepoPlugin extends Plugin implements RepositoryPlugin {
+
+        @Override
+        public Map<String, Repository.Factory> getRepositories(
+            Environment env,
+            NamedXContentRegistry namedXContentRegistry,
+            ClusterService clusterService,
+            RecoverySettings recoverySettings
+        ) {
+            return Collections.singletonMap(
+                REPO_TYPE,
+                (metadata) -> new FsRepository(metadata, env, namedXContentRegistry, clusterService, recoverySettings) {
+                    @Override
+                    protected void assertSnapshotOrGenericThread() {
+                        // eliminate thread name check as we access blobStore on test/main threads
+                    }
+                }
+            );
+        }
+    }
+
+    protected void createRepository(Client client, String repoName) {
+        AcknowledgedResponse putRepositoryResponse = client.admin()
+            .cluster()
+            .preparePutRepository(repoName)
+            .setType(REPO_TYPE)
+            .setSettings(
+                Settings.builder().put(node().settings()).put("location", OpenSearchIntegTestCase.randomRepoPath(node().settings()))
+            )
+            .get();
+        assertThat(putRepositoryResponse.isAcknowledged(), equalTo(true));
+    }
+
+    protected void createRepository(Client client, String repoName, Settings repoSettings) {
+        AcknowledgedResponse putRepositoryResponse = client.admin()
+            .cluster()
+            .preparePutRepository(repoName)
+            .setType(REPO_TYPE)
+            .setSettings(repoSettings)
+            .get();
+        assertThat(putRepositoryResponse.isAcknowledged(), equalTo(true));
+    }
+
+    protected void updateRepository(Client client, String repoName, Settings repoSettings) {
+        createRepository(client, repoName, repoSettings);
+    }
+
+    protected Settings getRemoteStoreBackedIndexSettings() {
+        return Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "1")
+            .put("index.refresh_interval", "300s")
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey())
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    protected void indexDocuments(Client client, String indexName) {
+        int numDocs = randomIntBetween(10, 20);
+        for (int i = 0; i < numDocs; i++) {
+            String id = Integer.toString(i);
+            client.prepareIndex(indexName).setId(id).setSource("text", "sometext").get();
+        }
+        client.admin().indices().prepareFlush(indexName).get();
+    }
+
+    protected IndexSettings getIndexSettings(String indexName) {
+        final IndicesService indicesService = getInstanceFromNode(IndicesService.class);
+        final IndexService indexService = indicesService.indexService(resolveIndex(indexName));
+        return indexService.getIndexSettings();
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRemoteIndexTests.java b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRemoteIndexTests.java
new file mode 100644
index 0000000000000..7bcc5aba6ce05
--- /dev/null
+++ b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRemoteIndexTests.java
@@ -0,0 +1,382 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.repositories.blobstore;
+
+import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesResponse;
+import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.env.Environment;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.snapshots.blobstore.RemoteStoreShardShallowCopySnapshot;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.repositories.IndexId;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.repositories.RepositoryData;
+import org.opensearch.repositories.fs.FsRepository;
+import org.opensearch.snapshots.SnapshotId;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.stream.Collectors;
+
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.hamcrest.Matchers.equalTo;
+
+/**
+ * Tests for the {@link BlobStoreRepository} and its subclasses.
+ */
+public class BlobStoreRepositoryRemoteIndexTests extends BlobStoreRepositoryHelperTests {
+    @Override
+    protected Settings nodeSettings() {
+        Path tempDir = createTempDir();
+        return Settings.builder()
+            .put(super.nodeSettings())
+            .put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), ReplicationType.SEGMENT)
+            .put(buildRemoteStoreNodeAttributes("test-rs-repo", tempDir.resolve("repo")))
+            .put(Environment.PATH_HOME_SETTING.getKey(), tempDir)
+            .put(Environment.PATH_REPO_SETTING.getKey(), tempDir.resolve("repo"))
+            .put(Environment.PATH_SHARED_DATA_SETTING.getKey(), tempDir.getParent())
+            .build();
+    }
+
+    private Settings buildRemoteStoreNodeAttributes(String repoName, Path repoPath) {
+        String repoTypeAttributeKey = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_TYPE_ATTRIBUTE_KEY_FORMAT,
+            repoName
+        );
+        String repoSettingsAttributeKeyPrefix = String.format(
+            Locale.getDefault(),
+            "node.attr." + REMOTE_STORE_REPOSITORY_SETTINGS_ATTRIBUTE_KEY_PREFIX,
+            repoName
+        );
+
+        return Settings.builder()
+            .put("node.attr." + REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, repoName)
+            .put(repoTypeAttributeKey, FsRepository.TYPE)
+            .put(repoSettingsAttributeKeyPrefix + "location", repoPath)
+            .put("node.attr." + REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, repoName)
+            .put(repoTypeAttributeKey, FsRepository.TYPE)
+            .put(repoSettingsAttributeKeyPrefix + "location", repoPath)
+            .put("node.attr." + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, repoName)
+            .put(repoTypeAttributeKey, FsRepository.TYPE)
+            .put(repoSettingsAttributeKeyPrefix + "location", repoPath)
+            .put(RemoteClusterStateService.REMOTE_CLUSTER_STATE_ENABLED_SETTING.getKey(), false)
+            .build();
+    }
+
+    // Validate Scenario Normal Snapshot -> remoteStoreShallowCopy Snapshot -> normal Snapshot
+    public void testRetrieveShallowCopySnapshotCase1() throws IOException {
+        final Client client = client();
+        final String snapshotRepositoryName = "test-repo";
+        final String remoteStoreRepositoryName = "test-rs-repo";
+
+        logger.info("-->  creating snapshot repository");
+
+        Settings snapshotRepoSettings = Settings.builder()
+            .put(node().settings())
+            .put("location", OpenSearchIntegTestCase.randomRepoPath(node().settings()))
+            .build();
+        createRepository(client, snapshotRepositoryName, snapshotRepoSettings);
+
+        logger.info("--> creating an index and indexing documents");
+        final String indexName = "test-idx";
+        createIndex(indexName);
+        ensureGreen();
+        indexDocuments(client, indexName);
+
+        logger.info("--> creating a remote store enabled index and indexing documents");
+        final String remoteStoreIndexName = "test-rs-idx";
+        Settings indexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreIndexName, indexSettings);
+        indexDocuments(client, remoteStoreIndexName);
+
+        logger.info("--> create first snapshot");
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-1")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId1 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        String[] lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 0) : "there should be no lock files present in directory, but found " + Arrays.toString(lockFiles);
+        logger.info("--> create remote index shallow snapshot");
+        Settings snapshotRepoSettingsForShallowCopy = Settings.builder()
+            .put(snapshotRepoSettings)
+            .put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), Boolean.TRUE)
+            .build();
+        updateRepository(client, snapshotRepositoryName, snapshotRepoSettingsForShallowCopy);
+
+        createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-2")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId2 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 1) : "there should be only one lock file, but found " + Arrays.toString(lockFiles);
+        assert lockFiles[0].endsWith(snapshotId2.getUUID() + ".lock");
+
+        logger.info("--> create another normal snapshot");
+        updateRepository(client, snapshotRepositoryName, snapshotRepoSettings);
+        createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-3")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId3 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 1) : "there should be only one lock file, but found " + Arrays.toString(lockFiles);
+        assert lockFiles[0].endsWith(snapshotId2.getUUID() + ".lock");
+
+        logger.info("--> make sure the node's repository can resolve the snapshots");
+        final List<SnapshotId> originalSnapshots = Arrays.asList(snapshotId1, snapshotId2, snapshotId3);
+
+        final RepositoriesService repositoriesService = getInstanceFromNode(RepositoriesService.class);
+        final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(snapshotRepositoryName);
+        RepositoryData repositoryData = OpenSearchBlobStoreRepositoryIntegTestCase.getRepositoryData(repository);
+        IndexId indexId = repositoryData.resolveIndexId(remoteStoreIndexName);
+
+        List<SnapshotId> snapshotIds = repositoryData.getSnapshotIds()
+            .stream()
+            .sorted((s1, s2) -> s1.getName().compareTo(s2.getName()))
+            .collect(Collectors.toList());
+        assertThat(snapshotIds, equalTo(originalSnapshots));
+
+        // shallow copy shard metadata - getRemoteStoreShallowCopyShardMetadata
+        RemoteStoreShardShallowCopySnapshot shardShallowCopySnapshot = repository.getRemoteStoreShallowCopyShardMetadata(
+            snapshotId2,
+            indexId,
+            new ShardId(remoteStoreIndexName, indexId.getId(), 0)
+        );
+        assertEquals(shardShallowCopySnapshot.getRemoteStoreRepository(), remoteStoreRepositoryName);
+    }
+
+    public void testGetRemoteStoreShallowCopyShardMetadata() throws IOException {
+        final Client client = client();
+        final String snapshotRepositoryName = "test-repo";
+        final String remoteStoreRepositoryName = "test-rs-repo";
+
+        logger.info("-->  creating snapshot repository");
+
+        Settings snapshotRepoSettings = Settings.builder()
+            .put(node().settings())
+            .put("location", OpenSearchIntegTestCase.randomRepoPath(node().settings()))
+            .build();
+        createRepository(client, snapshotRepositoryName, snapshotRepoSettings);
+
+        logger.info("--> creating a remote store enabled index and indexing documents");
+        final String remoteStoreIndexName = "test-rs-idx";
+        Settings indexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreIndexName, indexSettings);
+        indexDocuments(client, remoteStoreIndexName);
+
+        logger.info("--> create remote index shallow snapshot");
+        Settings snapshotRepoSettingsForShallowCopy = Settings.builder()
+            .put(snapshotRepoSettings)
+            .put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), Boolean.TRUE)
+            .build();
+        updateRepository(client, snapshotRepositoryName, snapshotRepoSettingsForShallowCopy);
+
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-2")
+            .setWaitForCompletion(true)
+            .setIndices(remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        String[] lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 1) : "there should be only one lock file, but found " + Arrays.toString(lockFiles);
+        assert lockFiles[0].endsWith(snapshotId.getUUID() + ".lock");
+
+        final RepositoriesService repositoriesService = getInstanceFromNode(RepositoriesService.class);
+        final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(snapshotRepositoryName);
+        RepositoryData repositoryData = OpenSearchBlobStoreRepositoryIntegTestCase.getRepositoryData(repository);
+        IndexSettings indexSetting = getIndexSettings(remoteStoreIndexName);
+        IndexId indexId = repositoryData.resolveIndexId(remoteStoreIndexName);
+        RemoteStoreShardShallowCopySnapshot shardShallowCopySnapshot = repository.getRemoteStoreShallowCopyShardMetadata(
+            snapshotId,
+            indexId,
+            new ShardId(remoteStoreIndexName, indexSetting.getUUID(), 0)
+        );
+        assertEquals(shardShallowCopySnapshot.getRemoteStoreRepository(), remoteStoreRepositoryName);
+        assertEquals(shardShallowCopySnapshot.getIndexUUID(), indexSetting.getUUID());
+        assertEquals(shardShallowCopySnapshot.getRepositoryBasePath(), "");
+    }
+
+    // Validate Scenario remoteStoreShallowCopy Snapshot -> remoteStoreShallowCopy Snapshot
+    // -> remoteStoreShallowCopy Snapshot -> normal snapshot
+    public void testRetrieveShallowCopySnapshotCase2() throws IOException {
+        final Client client = client();
+        final String snapshotRepositoryName = "test-repo";
+        final String remoteStoreRepositoryName = "test-rs-repo";
+
+        logger.info("-->  creating snapshot repository");
+        Settings snapshotRepoSettings = Settings.builder()
+            .put(node().settings())
+            .put("location", OpenSearchIntegTestCase.randomRepoPath(node().settings()))
+            .build();
+        createRepository(client, snapshotRepositoryName, snapshotRepoSettings);
+
+        GetRepositoriesResponse updatedGetRepositoriesResponse = client.admin()
+            .cluster()
+            .prepareGetRepositories(snapshotRepositoryName)
+            .get();
+
+        RepositoryMetadata updatedRepositoryMetadata = updatedGetRepositoriesResponse.repositories().get(0);
+
+        assertFalse(updatedRepositoryMetadata.settings().getAsBoolean(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), false));
+
+        logger.info("--> creating an index and indexing documents");
+        final String indexName = "test-idx";
+        createIndex(indexName);
+        ensureGreen();
+        indexDocuments(client, indexName);
+
+        logger.info("--> creating a remote store enabled index and indexing documents");
+        final String remoteStoreIndexName = "test-rs-idx";
+        Settings indexSettings = getRemoteStoreBackedIndexSettings();
+        createIndex(remoteStoreIndexName, indexSettings);
+        indexDocuments(client, remoteStoreIndexName);
+
+        logger.info("--> create first remote index shallow snapshot");
+
+        Settings snapshotRepoSettingsForShallowCopy = Settings.builder()
+            .put(snapshotRepoSettings)
+            .put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), true)
+            .build();
+        updateRepository(client, snapshotRepositoryName, snapshotRepoSettingsForShallowCopy);
+
+        updatedGetRepositoriesResponse = client.admin().cluster().prepareGetRepositories(snapshotRepositoryName).get();
+
+        updatedRepositoryMetadata = updatedGetRepositoriesResponse.repositories().get(0);
+
+        assertTrue(updatedRepositoryMetadata.settings().getAsBoolean(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), false));
+
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-1")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId1 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        String[] lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 1) : "lock files are " + Arrays.toString(lockFiles);
+        assert lockFiles[0].endsWith(snapshotId1.getUUID() + ".lock");
+
+        logger.info("--> create second remote index shallow snapshot");
+        createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-2")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId2 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 2) : "lock files are " + Arrays.toString(lockFiles);
+        List<SnapshotId> shallowCopySnapshotIDs = Arrays.asList(snapshotId1, snapshotId2);
+        for (SnapshotId snapshotId : shallowCopySnapshotIDs) {
+            assert lockFiles[0].contains(snapshotId.getUUID()) || lockFiles[1].contains(snapshotId.getUUID());
+        }
+        logger.info("--> create third remote index shallow snapshot");
+        createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-3")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId3 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 3);
+        shallowCopySnapshotIDs = Arrays.asList(snapshotId1, snapshotId2, snapshotId3);
+        for (SnapshotId snapshotId : shallowCopySnapshotIDs) {
+            assert lockFiles[0].contains(snapshotId.getUUID())
+                || lockFiles[1].contains(snapshotId.getUUID())
+                || lockFiles[2].contains(snapshotId.getUUID());
+        }
+        logger.info("--> create normal snapshot");
+        createRepository(client, snapshotRepositoryName, snapshotRepoSettings);
+        createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(snapshotRepositoryName, "test-snap-4")
+            .setWaitForCompletion(true)
+            .setIndices(indexName, remoteStoreIndexName)
+            .get();
+        final SnapshotId snapshotId4 = createSnapshotResponse.getSnapshotInfo().snapshotId();
+
+        lockFiles = getLockFilesInRemoteStore(remoteStoreIndexName, remoteStoreRepositoryName);
+        assert (lockFiles.length == 3) : "lock files are " + Arrays.toString(lockFiles);
+        shallowCopySnapshotIDs = Arrays.asList(snapshotId1, snapshotId2, snapshotId3);
+        for (SnapshotId snapshotId : shallowCopySnapshotIDs) {
+            assert lockFiles[0].contains(snapshotId.getUUID())
+                || lockFiles[1].contains(snapshotId.getUUID())
+                || lockFiles[2].contains(snapshotId.getUUID());
+        }
+
+        logger.info("--> make sure the node's repository can resolve the snapshots");
+        final List<SnapshotId> originalSnapshots = Arrays.asList(snapshotId1, snapshotId2, snapshotId3, snapshotId4);
+
+        final RepositoriesService repositoriesService = getInstanceFromNode(RepositoriesService.class);
+        final BlobStoreRepository repository = (BlobStoreRepository) repositoriesService.repository(snapshotRepositoryName);
+        List<SnapshotId> snapshotIds = OpenSearchBlobStoreRepositoryIntegTestCase.getRepositoryData(repository)
+            .getSnapshotIds()
+            .stream()
+            .sorted((s1, s2) -> s1.getName().compareTo(s2.getName()))
+            .collect(Collectors.toList());
+        assertThat(snapshotIds, equalTo(originalSnapshots));
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java
index 7cbe3d6dbd30a..e4e83f2453fa2 100644
--- a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java
+++ b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java
@@ -45,7 +45,9 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.index.snapshots.IndexShardSnapshotFailedException;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.index.engine.EngineConfigFactory;
@@ -54,8 +56,6 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.index.snapshots.IndexShardSnapshotFailedException;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.indices.recovery.RecoverySettings;
@@ -140,7 +140,8 @@ public void testRestoreSnapshotWithExistingFiles() throws IOException {
                 new EngineConfigFactory(shard.indexSettings()),
                 () -> {},
                 RetentionLeaseSyncer.EMPTY,
-                EMPTY_EVENT_LISTENER
+                EMPTY_EVENT_LISTENER,
+                null
             );
 
             // restore the shard
@@ -161,7 +162,7 @@ public void testRestoreSnapshotWithExistingFiles() throws IOException {
         } finally {
             if (shard != null && shard.state() != IndexShardState.CLOSED) {
                 try {
-                    shard.close("test", false);
+                    shard.close("test", false, false);
                 } finally {
                     IOUtils.close(shard.store());
                 }
@@ -211,7 +212,8 @@ public void testSnapshotWithConflictingName() throws Exception {
                         6,
                         Collections.emptyList(),
                         true,
-                        Collections.emptyMap()
+                        Collections.emptyMap(),
+                        false
                     ),
                     Version.CURRENT,
                     Function.identity(),
@@ -226,7 +228,7 @@ public void testSnapshotWithConflictingName() throws Exception {
         } finally {
             if (shard != null && shard.state() != IndexShardState.CLOSED) {
                 try {
-                    shard.close("test", false);
+                    shard.close("test", false, false);
                 } finally {
                     IOUtils.close(shard.store());
                 }
diff --git a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryTests.java b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryTests.java
index 94813d1f7cd33..1e86142d701aa 100644
--- a/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryTests.java
+++ b/server/src/test/java/org/opensearch/repositories/blobstore/BlobStoreRepositoryTests.java
@@ -41,8 +41,8 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
@@ -57,7 +57,6 @@
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotState;
 import org.opensearch.test.OpenSearchIntegTestCase;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
 import java.nio.file.Path;
 import java.util.Arrays;
@@ -75,7 +74,7 @@
 /**
  * Tests for the {@link BlobStoreRepository} and its subclasses.
  */
-public class BlobStoreRepositoryTests extends OpenSearchSingleNodeTestCase {
+public class BlobStoreRepositoryTests extends BlobStoreRepositoryHelperTests {
 
     static final String REPO_TYPE = "fsLike";
 
@@ -253,7 +252,7 @@ public void testBadChunksize() throws Exception {
         );
     }
 
-    public void testFsRepositoryCompressDeprecated() {
+    public void testFsRepositoryCompressDeprecatedIgnored() {
         final Path location = OpenSearchIntegTestCase.randomRepoPath(node().settings());
         final Settings settings = Settings.builder().put(node().settings()).put("location", location).build();
         final RepositoryMetadata metadata = new RepositoryMetadata("test-repo", REPO_TYPE, settings);
@@ -266,10 +265,7 @@ public void testFsRepositoryCompressDeprecated() {
 
         new FsRepository(metadata, useCompressEnvironment, null, BlobStoreTestUtil.mockClusterService(), null);
 
-        assertWarnings(
-            "[repositories.fs.compress] setting was deprecated in OpenSearch and will be removed in a future release!"
-                + " See the breaking changes documentation for the next major version."
-        );
+        assertNoDeprecationWarnings();
     }
 
     private static void writeIndexGen(BlobStoreRepository repository, RepositoryData repositoryData, long generation) throws Exception {
diff --git a/server/src/test/java/org/opensearch/repositories/fs/FsRepositoryTests.java b/server/src/test/java/org/opensearch/repositories/fs/FsRepositoryTests.java
index 2bfcec6e75ffc..d9f599714805b 100644
--- a/server/src/test/java/org/opensearch/repositories/fs/FsRepositoryTests.java
+++ b/server/src/test/java/org/opensearch/repositories/fs/FsRepositoryTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.repositories.fs;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.SortedDocValuesField;
@@ -44,9 +43,10 @@
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.IOSupplier;
-import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -58,23 +58,26 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.lucene.Lucene;
 import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.index.store.Store;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
 import org.opensearch.repositories.IndexId;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.DummyShardLock;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -89,6 +92,7 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
+import static org.hamcrest.Matchers.is;
 
 public class FsRepositoryTests extends OpenSearchTestCase {
 
@@ -103,6 +107,7 @@ public void testSnapshotAndRestore() throws IOException, InterruptedException {
                 .put("location", repo)
                 .put("compress", randomBoolean())
                 .put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES)
+                .put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path")
                 .build();
 
             int numDocs = indexDocs(directory);
@@ -203,12 +208,12 @@ public void testSnapshotAndRestore() throws IOException, InterruptedException {
             futureC.actionGet();
             assertEquals(secondState.getIndex().reusedFileCount(), commitFileNames.size() - 2);
             assertEquals(secondState.getIndex().recoveredFileCount(), 2);
-            List<RecoveryState.FileDetail> recoveredFiles = secondState.getIndex()
+            List<ReplicationLuceneIndex.FileMetadata> recoveredFiles = secondState.getIndex()
                 .fileDetails()
                 .stream()
                 .filter(f -> f.reused() == false)
                 .collect(Collectors.toList());
-            Collections.sort(recoveredFiles, Comparator.comparing(RecoveryState.FileDetail::name));
+            Collections.sort(recoveredFiles, Comparator.comparing(ReplicationLuceneIndex.FileMetadata::name));
             assertTrue(recoveredFiles.get(0).name(), recoveredFiles.get(0).name().endsWith(".liv"));
             assertTrue(recoveredFiles.get(1).name(), recoveredFiles.get(1).name().endsWith("segments_" + incIndexCommit.getGeneration()));
         } finally {
@@ -216,6 +221,31 @@ public void testSnapshotAndRestore() throws IOException, InterruptedException {
         }
     }
 
+    public void testRestrictedSettingsDefault() {
+        Path repo = createTempDir();
+        Settings settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toAbsolutePath())
+            .put(Environment.PATH_REPO_SETTING.getKey(), repo.toAbsolutePath())
+            .put("location", repo)
+            .put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path")
+            .build();
+        RepositoryMetadata metadata = new RepositoryMetadata("test", "fs", settings);
+        FsRepository repository = new FsRepository(
+            metadata,
+            new Environment(settings, null),
+            NamedXContentRegistry.EMPTY,
+            BlobStoreTestUtil.mockClusterService(),
+            new RecoverySettings(settings, new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        );
+
+        List<Setting<?>> restrictedSettings = repository.getRestrictedSystemRepositorySettings();
+        assertThat(restrictedSettings.size(), is(4));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.SYSTEM_REPOSITORY_SETTING));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.READONLY_SETTING));
+        assertTrue(restrictedSettings.contains(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY));
+        assertTrue(restrictedSettings.contains(FsRepository.LOCATION_SETTING));
+    }
+
     private void runGeneric(ThreadPool threadPool, Runnable runnable) throws InterruptedException {
         CountDownLatch latch = new CountDownLatch(1);
         threadPool.generic().submit(() -> {
diff --git a/server/src/test/java/org/opensearch/repositories/fs/ReloadableFsRepositoryTests.java b/server/src/test/java/org/opensearch/repositories/fs/ReloadableFsRepositoryTests.java
new file mode 100644
index 0000000000000..db2cf9c3e9582
--- /dev/null
+++ b/server/src/test/java/org/opensearch/repositories/fs/ReloadableFsRepositoryTests.java
@@ -0,0 +1,119 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.fs;
+
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.common.compress.DeflateCompressor;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.compress.ZstdCompressor;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.env.Environment;
+import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.nio.file.Path;
+import java.util.Locale;
+
+public class ReloadableFsRepositoryTests extends OpenSearchTestCase {
+    ReloadableFsRepository repository;
+    RepositoryMetadata metadata;
+    Settings settings;
+    Path repo;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+
+        repo = createTempDir();
+        settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toAbsolutePath())
+            .put(Environment.PATH_REPO_SETTING.getKey(), repo.toAbsolutePath())
+            .putList(Environment.PATH_DATA_SETTING.getKey(), tmpPaths())
+            .put("location", repo)
+            .put("compress", false)
+            .put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES)
+            .put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path")
+            .build();
+        metadata = new RepositoryMetadata("test", "fs", settings);
+        repository = new ReloadableFsRepository(
+            metadata,
+            new Environment(settings, null),
+            NamedXContentRegistry.EMPTY,
+            BlobStoreTestUtil.mockClusterService(),
+            new RecoverySettings(settings, new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        );
+    }
+
+    /**
+     * Validates that {@link ReloadableFsRepository} supports inplace reloading
+     */
+    public void testIsReloadable() {
+        assertTrue(repository.isReloadable());
+    }
+
+    /**
+     * Updates repository metadata of an existing repository to enable default compressor
+     */
+    public void testCompressReload() {
+        assertEquals(CompressorRegistry.none(), repository.getCompressor());
+        updateCompressionTypeToDefault();
+        repository.validateMetadata(metadata);
+        repository.reload(metadata);
+        assertEquals(CompressorRegistry.defaultCompressor(), repository.getCompressor());
+    }
+
+    /**
+     * Updates repository metadata of an existing repository to change compressor type from default to Zstd
+     */
+    public void testCompressionTypeReload() {
+        assertEquals(CompressorRegistry.none(), repository.getCompressor());
+        updateCompressionTypeToDefault();
+        repository = new ReloadableFsRepository(
+            metadata,
+            new Environment(settings, null),
+            NamedXContentRegistry.EMPTY,
+            BlobStoreTestUtil.mockClusterService(),
+            new RecoverySettings(settings, new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        );
+        assertEquals(CompressorRegistry.defaultCompressor(), repository.getCompressor());
+
+        settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toAbsolutePath())
+            .put(Environment.PATH_REPO_SETTING.getKey(), repo.toAbsolutePath())
+            .putList(Environment.PATH_DATA_SETTING.getKey(), tmpPaths())
+            .put("location", repo)
+            .put("compress", true)
+            .put("compression_type", ZstdCompressor.NAME.toLowerCase(Locale.ROOT))
+            .put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES)
+            .put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path")
+            .build();
+        metadata = new RepositoryMetadata("test", "fs", settings);
+        repository.validateMetadata(metadata);
+        repository.reload(metadata);
+        assertEquals(CompressorRegistry.getCompressor(ZstdCompressor.NAME.toUpperCase(Locale.ROOT)), repository.getCompressor());
+    }
+
+    private void updateCompressionTypeToDefault() {
+        settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toAbsolutePath())
+            .put(Environment.PATH_REPO_SETTING.getKey(), repo.toAbsolutePath())
+            .putList(Environment.PATH_DATA_SETTING.getKey(), tmpPaths())
+            .put("location", repo)
+            .put("compress", true)
+            .put("compression_type", DeflateCompressor.NAME.toLowerCase(Locale.ROOT))
+            .put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES)
+            .put(FsRepository.BASE_PATH_SETTING.getKey(), "my_base_path")
+            .build();
+        metadata = new RepositoryMetadata("test", "fs", settings);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/rest/BaseRestHandlerTests.java b/server/src/test/java/org/opensearch/rest/BaseRestHandlerTests.java
index 66ae5bdd6e3ec..ce929e64d8960 100644
--- a/server/src/test/java/org/opensearch/rest/BaseRestHandlerTests.java
+++ b/server/src/test/java/org/opensearch/rest/BaseRestHandlerTests.java
@@ -34,26 +34,26 @@
 
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.Table;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.rest.RestHandler.ReplacedRoute;
+import org.opensearch.rest.RestHandler.Route;
+import org.opensearch.rest.RestRequest.Method;
 import org.opensearch.rest.action.cat.AbstractCatAction;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestChannel;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.rest.RestRequest.Method;
-import org.opensearch.rest.RestHandler.Route;
-import org.opensearch.rest.RestHandler.ReplacedRoute;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
-import java.util.Arrays;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -299,7 +299,7 @@ public String getName() {
         try (XContentBuilder builder = JsonXContent.contentBuilder().startObject().endObject()) {
             final RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
                 new BytesArray(builder.toString()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             ).build();
             final RestChannel channel = new FakeRestChannel(request, randomBoolean(), 1);
             handler.handleRequest(request, channel, mockClient);
@@ -344,7 +344,7 @@ public String getName() {
         try (XContentBuilder builder = JsonXContent.contentBuilder().startObject().endObject()) {
             final RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
                 new BytesArray(builder.toString()),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             ).build();
             final RestChannel channel = new FakeRestChannel(request, randomBoolean(), 1);
             final IllegalArgumentException e = expectThrows(
diff --git a/server/src/test/java/org/opensearch/rest/BytesRestResponseTests.java b/server/src/test/java/org/opensearch/rest/BytesRestResponseTests.java
index 4e6d9b25409a8..9252475327b9a 100644
--- a/server/src/test/java/org/opensearch/rest/BytesRestResponseTests.java
+++ b/server/src/test/java/org/opensearch/rest/BytesRestResponseTests.java
@@ -33,20 +33,21 @@
 package org.opensearch.rest;
 
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.OpenSearchStatusException;
 import org.opensearch.OpenSearchException;
+import org.opensearch.OpenSearchStatusException;
 import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
@@ -117,7 +118,7 @@ public void testNonOpenSearchExceptionIsNotShownAsSimpleMessage() throws Excepti
         assertThat(text, not(containsString("UnknownException[an error occurred reading data]")));
         assertThat(text, not(containsString("FileNotFoundException[/foo/bar]")));
         assertThat(text, not(containsString("error_trace")));
-        assertThat(text, containsString("\"error\":\"No OpenSearchException found\""));
+        assertThat(text, containsString("\"error\":\"Internal failure\""));
     }
 
     public void testErrorTrace() throws Exception {
@@ -130,7 +131,7 @@ public void testErrorTrace() throws Exception {
         String text = response.content().utf8ToString();
         assertThat(text, containsString("\"type\":\"unknown_exception\",\"reason\":\"an error occurred reading data\""));
         assertThat(text, containsString("{\"type\":\"file_not_found_exception\""));
-        assertThat(text, containsString("\"stack_trace\":\"[an error occurred reading data]"));
+        assertThat(text, containsString("\"stack_trace\":\"OpenSearchException[an error occurred reading data]"));
     }
 
     public void testGuessRootCause() throws IOException {
@@ -325,7 +326,7 @@ public void testErrorToAndFromXContent() throws IOException {
 
         final XContentType xContentType = randomFrom(XContentType.values());
 
-        Map<String, String> params = Collections.singletonMap("format", xContentType.mediaType());
+        Map<String, String> params = Collections.singletonMap("format", xContentType.format());
         RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(params).build();
         RestChannel channel = detailed ? new DetailedExceptionRestChannel(request) : new SimpleExceptionRestChannel(request);
 
diff --git a/server/src/test/java/org/opensearch/rest/DeprecationRestHandlerTests.java b/server/src/test/java/org/opensearch/rest/DeprecationRestHandlerTests.java
index 9b0f826b67367..a7dba22621d88 100644
--- a/server/src/test/java/org/opensearch/rest/DeprecationRestHandlerTests.java
+++ b/server/src/test/java/org/opensearch/rest/DeprecationRestHandlerTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.test.OpenSearchTestCase;
-
 import org.junit.Before;
+
 import org.mockito.InOrder;
 
 import static org.mockito.Mockito.inOrder;
diff --git a/server/src/test/java/org/opensearch/rest/NamedRouteTests.java b/server/src/test/java/org/opensearch/rest/NamedRouteTests.java
new file mode 100644
index 0000000000000..cf3e2b5b858bf
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/NamedRouteTests.java
@@ -0,0 +1,163 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest;
+
+import org.opensearch.OpenSearchException;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Set;
+import java.util.function.Function;
+
+import static org.opensearch.rest.NamedRoute.MAX_LENGTH_OF_ACTION_NAME;
+import static org.opensearch.rest.RestRequest.Method.GET;
+
+public class NamedRouteTests extends OpenSearchTestCase {
+
+    public void testNamedRouteWithEmptyName() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("").build();
+            fail("Expected NamedRoute to throw exception on empty name provided");
+        } catch (OpenSearchException e) {
+            assertTrue(e.getMessage().contains("Invalid route name specified"));
+        }
+    }
+
+    public void testNamedRouteWithNameContainingSpace() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo bar").build();
+            fail("Expected NamedRoute to throw exception on name containing space name provided");
+        } catch (OpenSearchException e) {
+            assertTrue(e.getMessage().contains("Invalid route name specified"));
+        }
+    }
+
+    public void testNamedRouteWithNameContainingInvalidCharacters() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo@bar!").build();
+            fail("Expected NamedRoute to throw exception on name containing invalid characters name provided");
+        } catch (OpenSearchException e) {
+            assertTrue(e.getMessage().contains("Invalid route name specified"));
+        }
+    }
+
+    public void testNamedRouteWithNameOverMaximumLength() {
+        try {
+            String repeated = new String(new char[MAX_LENGTH_OF_ACTION_NAME + 1]).replace("\0", "x");
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName(repeated).build();
+            fail("Expected NamedRoute to throw exception on name over maximum length supplied");
+        } catch (OpenSearchException e) {
+            assertTrue(e.getMessage().contains("Invalid route name specified"));
+        }
+    }
+
+    public void testNamedRouteWithValidActionName() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar").build();
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to throw exception on valid action name");
+        }
+    }
+
+    public void testNamedRouteWithValidActionNameWithForwardSlash() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar:baz").build();
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to throw exception on valid action name");
+        }
+    }
+
+    public void testNamedRouteWithValidActionNameWithWildcard() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar/*").build();
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to throw exception on valid action name");
+        }
+    }
+
+    public void testNamedRouteWithValidActionNameWithUnderscore() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar_baz").build();
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to throw exception on valid action name");
+        }
+    }
+
+    public void testNamedRouteWithNullLegacyActionNames() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar").legacyActionNames(null).build();
+            assertTrue(r.actionNames().isEmpty());
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to pass with an invalid legacy action name");
+        }
+    }
+
+    public void testNamedRouteWithInvalidLegacyActionNames() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET)
+                .path("foo/bar")
+                .uniqueName("foo:bar")
+                .legacyActionNames(Set.of("foo:bar-legacy"))
+                .build();
+            fail("Did not expect NamedRoute to pass with an invalid legacy action name");
+        } catch (OpenSearchException e) {
+            assertTrue(e.getMessage().contains("Invalid action name [foo:bar-legacy]. It must start with one of:"));
+        }
+    }
+
+    public void testNamedRouteWithHandler() {
+        Function<RestRequest, RestResponse> fooHandler = restRequest -> null;
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar_baz").handler(fooHandler).build();
+            assertEquals(r.handler(), fooHandler);
+        } catch (OpenSearchException e) {
+            fail("Did not expect NamedRoute to throw exception");
+        }
+    }
+
+    public void testNamedRouteNullChecks() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(null).path("foo/bar").uniqueName("foo:bar_baz").build();
+            fail("Expected NamedRoute to throw exception as method should not be null");
+        } catch (NullPointerException e) {
+            assertEquals("REST method must not be null.", e.getMessage());
+        }
+
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path(null).uniqueName("foo:bar_baz").build();
+            fail("Expected NamedRoute to throw exception as path should not be null");
+        } catch (NullPointerException e) {
+            assertEquals("REST path must not be null.", e.getMessage());
+        }
+
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName(null).build();
+            fail("Expected NamedRoute to throw exception as route name should not be null");
+        } catch (NullPointerException e) {
+            assertEquals("REST route name must not be null.", e.getMessage());
+        }
+
+        try {
+            NamedRoute r = new NamedRoute.Builder().method(GET).path("foo/bar").uniqueName("foo:bar_baz").handler(null).build();
+            fail("Expected NamedRoute to throw exception as handler should not be null");
+        } catch (NullPointerException e) {
+            assertEquals("Route handler must not be null.", e.getMessage());
+        }
+    }
+
+    public void testNamedRouteEmptyBuild() {
+        try {
+            NamedRoute r = new NamedRoute.Builder().build();
+            fail("Expected NamedRoute to throw exception as fields should not be null");
+        } catch (IllegalStateException e) {
+            assertEquals("REST method, path and uniqueName are required.", e.getMessage());
+        }
+
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/rest/RestControllerTests.java b/server/src/test/java/org/opensearch/rest/RestControllerTests.java
index 6004613c0ed17..a237cd3b22973 100644
--- a/server/src/test/java/org/opensearch/rest/RestControllerTests.java
+++ b/server/src/test/java/org/opensearch/rest/RestControllerTests.java
@@ -33,25 +33,29 @@
 package org.opensearch.rest;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpStats;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpNodeClient;
@@ -77,8 +81,8 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doCallRealMethod;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
@@ -91,6 +95,7 @@ public class RestControllerTests extends OpenSearchTestCase {
     private RestController restController;
     private HierarchyCircuitBreakerService circuitBreakerService;
     private UsageService usageService;
+    private IdentityService identityService;
     private NodeClient client;
 
     @Before
@@ -108,9 +113,11 @@ public void setup() {
         // we can do this here only because we know that we don't adjust breaker settings dynamically in the test
         inFlightRequestsBreaker = circuitBreakerService.getBreaker(CircuitBreaker.IN_FLIGHT_REQUESTS);
 
+        identityService = new IdentityService(Settings.EMPTY, List.of());
+
         HttpServerTransport httpServerTransport = new TestHttpServerTransport();
         client = new NoOpNodeClient(this.getTestName());
-        restController = new RestController(Collections.emptySet(), null, client, circuitBreakerService, usageService);
+        restController = new RestController(Collections.emptySet(), null, client, circuitBreakerService, usageService, identityService);
         restController.registerHandler(
             RestRequest.Method.GET,
             "/",
@@ -118,11 +125,9 @@ public void setup() {
                 new BytesRestResponse(RestStatus.OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY)
             )
         );
-        restController.registerHandler(
-            RestRequest.Method.GET,
-            "/error",
-            (request, channel, client) -> { throw new IllegalArgumentException("test error"); }
-        );
+        restController.registerHandler(RestRequest.Method.GET, "/error", (request, channel, client) -> {
+            throw new IllegalArgumentException("test error");
+        });
 
         httpServerTransport.start();
     }
@@ -137,7 +142,7 @@ public void testApplyRelevantHeaders() throws Exception {
         Set<RestHeaderDefinition> headers = new HashSet<>(
             Arrays.asList(new RestHeaderDefinition("header.1", true), new RestHeaderDefinition("header.2", true))
         );
-        final RestController restController = new RestController(headers, null, null, circuitBreakerService, usageService);
+        final RestController restController = new RestController(headers, null, null, circuitBreakerService, usageService, identityService);
         Map<String, List<String>> restHeaders = new HashMap<>();
         restHeaders.put("header.1", Collections.singletonList("true"));
         restHeaders.put("header.2", Collections.singletonList("true"));
@@ -173,7 +178,7 @@ public void testRequestWithDisallowedMultiValuedHeader() {
         Set<RestHeaderDefinition> headers = new HashSet<>(
             Arrays.asList(new RestHeaderDefinition("header.1", true), new RestHeaderDefinition("header.2", false))
         );
-        final RestController restController = new RestController(headers, null, null, circuitBreakerService, usageService);
+        final RestController restController = new RestController(headers, null, null, circuitBreakerService, usageService, identityService);
         Map<String, List<String>> restHeaders = new HashMap<>();
         restHeaders.put("header.1", Collections.singletonList("boo"));
         restHeaders.put("header.2", Arrays.asList("foo", "bar"));
@@ -188,7 +193,14 @@ public void testRequestWithDisallowedMultiValuedHeaderButSameValues() {
         Set<RestHeaderDefinition> headers = new HashSet<>(
             Arrays.asList(new RestHeaderDefinition("header.1", true), new RestHeaderDefinition("header.2", false))
         );
-        final RestController restController = new RestController(headers, null, client, circuitBreakerService, usageService);
+        final RestController restController = new RestController(
+            headers,
+            null,
+            client,
+            circuitBreakerService,
+            usageService,
+            identityService
+        );
         Map<String, List<String>> restHeaders = new HashMap<>();
         restHeaders.put("header.1", Collections.singletonList("boo"));
         restHeaders.put("header.2", Arrays.asList("foo", "foo"));
@@ -249,7 +261,7 @@ public void testRegisterWithDeprecatedHandler() {
     }
 
     public void testRegisterSecondMethodWithDifferentNamedWildcard() {
-        final RestController restController = new RestController(null, null, null, circuitBreakerService, usageService);
+        final RestController restController = new RestController(null, null, null, circuitBreakerService, usageService, identityService);
 
         RestRequest.Method firstMethod = randomFrom(RestRequest.Method.values());
         RestRequest.Method secondMethod = randomFrom(
@@ -277,9 +289,9 @@ public void testRestHandlerWrapper() throws Exception {
         final RestController restController = new RestController(Collections.emptySet(), h -> {
             assertSame(handler, h);
             return (RestRequest request, RestChannel channel, NodeClient client) -> wrapperCalled.set(true);
-        }, client, circuitBreakerService, usageService);
+        }, client, circuitBreakerService, usageService, identityService);
         restController.registerHandler(RestRequest.Method.GET, "/wrapped", handler);
-        RestRequest request = testRestRequest("/wrapped", "{}", XContentType.JSON);
+        RestRequest request = testRestRequest("/wrapped", "{}", MediaTypeRegistry.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.BAD_REQUEST);
         restController.dispatchRequest(request, channel, client.threadPool().getThreadContext());
         httpServerTransport.start();
@@ -290,7 +302,7 @@ public void testRestHandlerWrapper() throws Exception {
     public void testDispatchRequestAddsAndFreesBytesOnSuccess() {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAlphaOfLength((int) Math.round(contentLength / inFlightRequestsBreaker.getOverhead()));
-        RestRequest request = testRestRequest("/", content, XContentType.JSON);
+        RestRequest request = testRestRequest("/", content, MediaTypeRegistry.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.OK);
 
         restController.dispatchRequest(request, channel, client.threadPool().getThreadContext());
@@ -302,7 +314,7 @@ public void testDispatchRequestAddsAndFreesBytesOnSuccess() {
     public void testDispatchRequestAddsAndFreesBytesOnError() {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAlphaOfLength((int) Math.round(contentLength / inFlightRequestsBreaker.getOverhead()));
-        RestRequest request = testRestRequest("/error", content, XContentType.JSON);
+        RestRequest request = testRestRequest("/error", content, MediaTypeRegistry.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.BAD_REQUEST);
 
         restController.dispatchRequest(request, channel, client.threadPool().getThreadContext());
@@ -315,7 +327,7 @@ public void testDispatchRequestAddsAndFreesBytesOnlyOnceOnError() {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAlphaOfLength((int) Math.round(contentLength / inFlightRequestsBreaker.getOverhead()));
         // we will produce an error in the rest handler and one more when sending the error response
-        RestRequest request = testRestRequest("/error", content, XContentType.JSON);
+        RestRequest request = testRestRequest("/error", content, MediaTypeRegistry.JSON);
         ExceptionThrowingChannel channel = new ExceptionThrowingChannel(request, true);
 
         restController.dispatchRequest(request, channel, client.threadPool().getThreadContext());
@@ -327,7 +339,7 @@ public void testDispatchRequestAddsAndFreesBytesOnlyOnceOnError() {
     public void testDispatchRequestLimitsBytes() {
         int contentLength = BREAKER_LIMIT.bytesAsInt() + 1;
         String content = randomAlphaOfLength((int) Math.round(contentLength / inFlightRequestsBreaker.getOverhead()));
-        RestRequest request = testRestRequest("/", content, XContentType.JSON);
+        RestRequest request = testRestRequest("/", content, MediaTypeRegistry.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.TOO_MANY_REQUESTS);
 
         restController.dispatchRequest(request, channel, client.threadPool().getThreadContext());
@@ -340,7 +352,7 @@ public void testDispatchRequiresContentTypeForRequestsWithContent() {
         String content = randomAlphaOfLength((int) Math.round(BREAKER_LIMIT.getBytes() / inFlightRequestsBreaker.getOverhead()));
         RestRequest request = testRestRequest("/", content, null);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.NOT_ACCEPTABLE);
-        restController = new RestController(Collections.emptySet(), null, null, circuitBreakerService, usageService);
+        restController = new RestController(Collections.emptySet(), null, null, circuitBreakerService, usageService, identityService);
         restController.registerHandler(
             RestRequest.Method.GET,
             "/",
@@ -553,6 +565,15 @@ public void testFaviconWithWrongHttpMethod() {
         assertThat(channel.getRestResponse().getHeaders().get("Allow"), hasItem(equalTo(RestRequest.Method.GET.toString())));
     }
 
+    public void testHandleBadRequestWithHtmlSpecialCharsInUri() {
+        final FakeRestRequest fakeRestRequest = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY).withPath(
+            "/<script>alert('xss');alert(\"&#x6A&#x61&#x76&#x61\");</script>"
+        ).build();
+        final AssertingChannel channel = new AssertingChannel(fakeRestRequest, true, RestStatus.BAD_REQUEST);
+        restController.dispatchRequest(fakeRestRequest, channel, client.threadPool().getThreadContext());
+        assertThat(channel.getRestResponse().content().utf8ToString(), containsString("invalid uri has been requested"));
+    }
+
     public void testDispatchUnsupportedHttpMethod() {
         final boolean hasContent = randomBoolean();
         final RestRequest request = RestRequest.request(xContentRegistry(), new HttpRequest() {
@@ -623,6 +644,10 @@ public Exception getInboundException() {
         assertTrue(channel.getSendResponseCalled());
         assertThat(channel.getRestResponse().getHeaders().containsKey("Allow"), equalTo(true));
         assertThat(channel.getRestResponse().getHeaders().get("Allow"), hasItem(equalTo(RestRequest.Method.GET.toString())));
+        assertThat(
+            channel.getRestResponse().content().utf8ToString(),
+            equalTo("{\"error\":\"Unexpected HTTP method, allowed: [GET]\",\"status\":405}")
+        );
     }
 
     private static final class TestHttpServerTransport extends AbstractLifecycleComponent implements HttpServerTransport {
@@ -693,10 +718,10 @@ public void sendResponse(RestResponse response) {
         }
     }
 
-    private static RestRequest testRestRequest(String path, String content, XContentType xContentType) {
+    private static RestRequest testRestRequest(String path, String content, MediaType mediaType) {
         FakeRestRequest.Builder builder = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY);
         builder.withPath(path);
-        builder.withContent(new BytesArray(content), xContentType);
+        builder.withContent(new BytesArray(content), mediaType);
         return builder.build();
     }
 }
diff --git a/server/src/test/java/org/opensearch/rest/RestHttpResponseHeadersTests.java b/server/src/test/java/org/opensearch/rest/RestHttpResponseHeadersTests.java
index 2ac2b3bb5a964..5d677247b8b6d 100644
--- a/server/src/test/java/org/opensearch/rest/RestHttpResponseHeadersTests.java
+++ b/server/src/test/java/org/opensearch/rest/RestHttpResponseHeadersTests.java
@@ -33,11 +33,13 @@
 package org.opensearch.rest;
 
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestChannel;
@@ -104,7 +106,15 @@ public void testUnsupportedMethodResponseHttpHeader() throws Exception {
 
         final Settings settings = Settings.EMPTY;
         UsageService usageService = new UsageService();
-        RestController restController = new RestController(Collections.emptySet(), null, null, circuitBreakerService, usageService);
+        final IdentityService identityService = new IdentityService(settings, List.of());
+        RestController restController = new RestController(
+            Collections.emptySet(),
+            null,
+            null,
+            circuitBreakerService,
+            usageService,
+            identityService
+        );
 
         // A basic RestHandler handles requests to the endpoint
         RestHandler restHandler = new RestHandler() {
diff --git a/server/src/test/java/org/opensearch/rest/RestRequestTests.java b/server/src/test/java/org/opensearch/rest/RestRequestTests.java
index d5a915b42cf87..ea603804bee89 100644
--- a/server/src/test/java/org/opensearch/rest/RestRequestTests.java
+++ b/server/src/test/java/org/opensearch/rest/RestRequestTests.java
@@ -34,13 +34,12 @@
 
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.MapBuilder;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.test.OpenSearchTestCase;
@@ -51,13 +50,11 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
-import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.mockito.Mockito.mock;
@@ -206,12 +203,12 @@ public void testContentTypeParsing() {
             Map<String, List<String>> map = new HashMap<>();
             map.put("Content-Type", Collections.singletonList(xContentType.mediaType()));
             RestRequest restRequest = contentRestRequest("", Collections.emptyMap(), map);
-            assertEquals(xContentType, restRequest.getXContentType());
+            assertEquals(xContentType, restRequest.getMediaType());
 
             map = new HashMap<>();
             map.put("Content-Type", Collections.singletonList(xContentType.mediaTypeWithoutParameters()));
             restRequest = contentRestRequest("", Collections.emptyMap(), map);
-            assertEquals(xContentType, restRequest.getXContentType());
+            assertEquals(xContentType, restRequest.getMediaType());
         }
     }
 
@@ -224,7 +221,7 @@ public void testPlainTextSupport() {
                 Collections.singletonList(randomFrom("text/plain", "text/plain; charset=utf-8", "text/plain;charset=utf-8"))
             )
         );
-        assertNull(restRequest.getXContentType());
+        assertNull(restRequest.getMediaType());
     }
 
     public void testMalformedContentTypeHeader() {
@@ -240,7 +237,7 @@ public void testMalformedContentTypeHeader() {
 
     public void testNoContentTypeHeader() {
         RestRequest contentRestRequest = contentRestRequest("", Collections.emptyMap(), Collections.emptyMap());
-        assertNull(contentRestRequest.getXContentType());
+        assertNull(contentRestRequest.getMediaType());
     }
 
     public void testMultipleContentTypeHeaders() {
@@ -283,40 +280,6 @@ public void testRequiredContent() {
         assertEquals("unknown content type", e.getMessage());
     }
 
-    /*
-     * The test is added in 2.0 when the request parameter "cluster_manager_timeout" is introduced.
-     * Remove the test along with the removal of the non-inclusive terminology "master_timeout".
-     */
-    public void testValidateParamValuesAreEqualWhenTheyAreEqual() {
-        FakeRestRequest request = new FakeRestRequest();
-        String valueForKey1 = randomFrom("value1", "", null);
-        String valueForKey2 = "value1";
-        request.params().put("key1", valueForKey1);
-        request.params().put("key2", valueForKey2);
-        request.validateParamValuesAreEqual("key1", "key2");
-        assertTrue(
-            String.format(
-                Locale.ROOT,
-                "The 2 values should be equal, or having 1 null/empty value. Value of key1: %s. Value of key2: %s",
-                valueForKey1,
-                valueForKey2
-            ),
-            Strings.isNullOrEmpty(valueForKey1) || valueForKey1.equals(valueForKey2)
-        );
-    }
-
-    /*
-     * The test is added in 2.0 when the request parameter "cluster_manager_timeout" is introduced.
-     * Remove the test along with the removal of the non-inclusive terminology "master_timeout".
-     */
-    public void testValidateParamValuesAreEqualWhenTheyAreNotEqual() {
-        FakeRestRequest request = new FakeRestRequest();
-        request.params().put("key1", "value1");
-        request.params().put("key2", "value2");
-        Exception e = assertThrows(OpenSearchParseException.class, () -> request.validateParamValuesAreEqual("key1", "key2"));
-        assertThat(e.getMessage(), containsString("The values of the request parameters: [key1, key2] are required to be equal"));
-    }
-
     private static RestRequest contentRestRequest(String content, Map<String, String> params) {
         Map<String, List<String>> headers = new HashMap<>();
         headers.put("Content-Type", Collections.singletonList("application/json"));
diff --git a/server/src/test/java/org/opensearch/rest/action/RestActionListenerTests.java b/server/src/test/java/org/opensearch/rest/action/RestActionListenerTests.java
index a674fff80e3f7..7c41607f12bfb 100644
--- a/server/src/test/java/org/opensearch/rest/action/RestActionListenerTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/RestActionListenerTests.java
@@ -14,7 +14,7 @@
 package org.opensearch.rest.action;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestChannel;
 import org.opensearch.test.rest.FakeRestRequest;
diff --git a/server/src/test/java/org/opensearch/rest/action/RestActionsTests.java b/server/src/test/java/org/opensearch/rest/action/RestActionsTests.java
index cdbaa00634c28..d0a71deb2a5c4 100644
--- a/server/src/test/java/org/opensearch/rest/action/RestActionsTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/RestActionsTests.java
@@ -33,22 +33,22 @@
 package org.opensearch.rest.action;
 
 import com.fasterxml.jackson.core.io.JsonEOFException;
+
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.action.ShardOperationFailedException;
 import org.opensearch.action.search.ShardSearchFailure;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ShardOperationFailedException;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.MatchQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchShardTarget;
 import org.opensearch.test.OpenSearchTestCase;
@@ -138,7 +138,7 @@ public void testBuildBroadcastShardsHeader() throws IOException {
         RestActions.buildBroadcastShardsHeader(builder, ToXContent.EMPTY_PARAMS, 12, 3, 0, 9, failures);
         builder.endObject();
         assertThat(
-            Strings.toString(builder),
+            builder.toString(),
             equalTo(
                 "{\n"
                     + "  \"_shards\" : {\n"
diff --git a/server/src/test/java/org/opensearch/rest/action/RestBuilderListenerTests.java b/server/src/test/java/org/opensearch/rest/action/RestBuilderListenerTests.java
index 9022ca613bbd5..cd91d7c2a97b3 100644
--- a/server/src/test/java/org/opensearch/rest/action/RestBuilderListenerTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/RestBuilderListenerTests.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.rest.action;
 
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestChannel;
 import org.opensearch.test.rest.FakeRestRequest;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 
 import java.util.concurrent.atomic.AtomicReference;
 
diff --git a/server/src/test/java/org/opensearch/rest/action/RestCancellableNodeClientTests.java b/server/src/test/java/org/opensearch/rest/action/RestCancellableNodeClientTests.java
index 0a4282451538e..f7c311674002c 100644
--- a/server/src/test/java/org/opensearch/rest/action/RestCancellableNodeClientTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/RestCancellableNodeClientTests.java
@@ -32,9 +32,7 @@
 
 package org.opensearch.rest.action;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksAction;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
@@ -44,10 +42,12 @@
 import org.opensearch.action.support.PlainListenableActionFuture;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.tasks.Task;
-import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/rest/action/RestMainActionTests.java b/server/src/test/java/org/opensearch/rest/action/RestMainActionTests.java
index f511b08138bbe..e4413daa0dfb1 100644
--- a/server/src/test/java/org/opensearch/rest/action/RestMainActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/RestMainActionTests.java
@@ -36,13 +36,13 @@
 import org.opensearch.Version;
 import org.opensearch.action.main.MainResponse;
 import org.opensearch.cluster.ClusterName;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionActionTests.java
index 629bb3ca5f358..80fb43a706e0e 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestAddVotingConfigExclusionActionTests.java
@@ -33,11 +33,12 @@
 package org.opensearch.rest.action.admin.cluster;
 
 import org.opensearch.action.admin.cluster.configuration.AddVotingConfigExclusionsRequest;
-import org.opensearch.common.Strings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.test.rest.FakeRestRequest;
 import org.opensearch.test.rest.RestActionTestCase;
 import org.junit.Before;
+
 import java.util.HashMap;
 import java.util.Map;
 
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterAddWeightedRoutingActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterAddWeightedRoutingActionTests.java
new file mode 100644
index 0000000000000..d8a29c6dbf5af
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterAddWeightedRoutingActionTests.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import com.fasterxml.jackson.core.JsonParseException;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.put.ClusterPutWeightedRoutingRequest;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.test.rest.FakeRestRequest;
+import org.opensearch.test.rest.RestActionTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.util.Collections.singletonMap;
+
+public class RestClusterAddWeightedRoutingActionTests extends RestActionTestCase {
+    private RestClusterPutWeightedRoutingAction action;
+
+    @Before
+    public void setupAction() {
+        action = new RestClusterPutWeightedRoutingAction();
+        controller().registerHandler(action);
+    }
+
+    public void testCreateRequest_SupportedRequestBody() throws IOException {
+        String req = "{\"weights\":{\"us-east-1c\":\"0\",\"us-east-1b\":\"1\",\"us-east-1a\":\"1\"},\"_version\":1}";
+        RestRequest restRequest = buildRestRequest(req);
+        ClusterPutWeightedRoutingRequest clusterPutWeightedRoutingRequest = RestClusterPutWeightedRoutingAction.createRequest(restRequest);
+        assertEquals("zone", clusterPutWeightedRoutingRequest.getWeightedRouting().attributeName());
+        assertNotNull(clusterPutWeightedRoutingRequest.getWeightedRouting().weights());
+        assertEquals("0.0", clusterPutWeightedRoutingRequest.getWeightedRouting().weights().get("us-east-1c").toString());
+        assertEquals("1.0", clusterPutWeightedRoutingRequest.getWeightedRouting().weights().get("us-east-1b").toString());
+        assertEquals("1.0", clusterPutWeightedRoutingRequest.getWeightedRouting().weights().get("us-east-1a").toString());
+        assertEquals(1, clusterPutWeightedRoutingRequest.getVersion());
+    }
+
+    public void testCreateRequest_UnsupportedRequestBody() throws IOException {
+        Map<String, String> params = new HashMap<>();
+        String req = "[\"us-east-1c\" : \"1\", \"us-east-1d\":\"1\", \"us-east-1a\":\"0\"]";
+        RestRequest restRequest = buildRestRequest(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterPutWeightedRoutingAction.createRequest(restRequest));
+    }
+
+    public void testCreateRequest_MalformedRequestBody() throws IOException {
+        Map<String, String> params = new HashMap<>();
+
+        String req = "{\"weights\":{\"us-east-1c\":\"0,\"us-east-1b\":\"1\",\"us-east-1a\":\"1\"},\"_version\":1}";
+        RestRequest restRequest = buildRestRequest(req);
+        assertThrows(JsonParseException.class, () -> RestClusterPutWeightedRoutingAction.createRequest(restRequest));
+    }
+
+    public void testCreateRequest_EmptyRequestBody() throws IOException {
+        String req = "{}";
+        RestRequest restRequest = buildRestRequest(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterPutWeightedRoutingAction.createRequest(restRequest));
+    }
+
+    private RestRequest buildRestRequest(String content) {
+        return new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.PUT)
+            .withPath("/_cluster/routing/awareness/zone/weights")
+            .withParams(singletonMap("attribute", "zone"))
+            .withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .build();
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingActionTests.java
new file mode 100644
index 0000000000000..ed9ed4207bec6
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterDeleteWeightedRoutingActionTests.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.action.admin.cluster.shards.routing.weighted.delete.ClusterDeleteWeightedRoutingRequest;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.test.rest.FakeRestRequest;
+import org.opensearch.test.rest.RestActionTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+
+import static java.util.Collections.singletonMap;
+
+public class RestClusterDeleteWeightedRoutingActionTests extends RestActionTestCase {
+    private RestClusterPutWeightedRoutingAction action;
+
+    @Before
+    public void setupAction() {
+        action = new RestClusterPutWeightedRoutingAction();
+        controller().registerHandler(action);
+    }
+
+    public void testDeleteRequest_SupportedRequestBody() throws IOException {
+        String req = "{\"_version\":2}";
+        RestRequest restRequest = buildRestRequest(req);
+        ClusterDeleteWeightedRoutingRequest clusterDeleteWeightedRoutingRequest = RestClusterDeleteWeightedRoutingAction.createRequest(
+            restRequest
+        );
+        assertEquals(2, clusterDeleteWeightedRoutingRequest.getVersion());
+
+        restRequest = buildRestRequestWithAwarenessAttribute(req);
+        clusterDeleteWeightedRoutingRequest = RestClusterDeleteWeightedRoutingAction.createRequest(restRequest);
+        assertEquals("zone", clusterDeleteWeightedRoutingRequest.getAwarenessAttribute());
+        assertEquals(2, clusterDeleteWeightedRoutingRequest.getVersion());
+    }
+
+    public void testDeleteRequest_BadRequest() throws IOException {
+        String req = "{\"_ver\":2}";
+        RestRequest restRequest = buildRestRequest(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterDeleteWeightedRoutingAction.createRequest(restRequest));
+
+        RestRequest restRequest2 = buildRestRequestWithAwarenessAttribute(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterDeleteWeightedRoutingAction.createRequest(restRequest2));
+    }
+
+    private RestRequest buildRestRequestWithAwarenessAttribute(String content) {
+        return new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.DELETE)
+            .withPath("/_cluster/routing/awareness/zone/weights")
+            .withParams(singletonMap("attribute", "zone"))
+            .withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .build();
+    }
+
+    private RestRequest buildRestRequest(String content) {
+        return new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.DELETE)
+            .withPath("/_cluster/routing/awareness/weights")
+            .withContent(new BytesArray(content), MediaTypeRegistry.JSON)
+            .build();
+    }
+
+    public void testCreateRequest_EmptyRequestBody() throws IOException {
+        String req = "{}";
+        RestRequest restRequest = buildRestRequest(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterDeleteWeightedRoutingAction.createRequest(restRequest));
+
+        RestRequest restRequest2 = buildRestRequestWithAwarenessAttribute(req);
+        assertThrows(OpenSearchParseException.class, () -> RestClusterDeleteWeightedRoutingAction.createRequest(restRequest2));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthActionTests.java
index 4f065653b44a6..31a0ebfd6c805 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestClusterHealthActionTests.java
@@ -52,7 +52,11 @@ public void testFromRequest() {
         Map<String, String> params = new HashMap<>();
         String index = "index";
         boolean local = randomBoolean();
-        String masterTimeout = randomTimeValue();
+        boolean ensureLocalWeighedIn = false;
+        if (local) {
+            ensureLocalWeighedIn = randomBoolean();
+        }
+        String clusterManagerTimeout = randomTimeValue();
         String timeout = randomTimeValue();
         ClusterHealthStatus waitForStatus = randomFrom(ClusterHealthStatus.values());
         boolean waitForNoRelocatingShards = randomBoolean();
@@ -63,7 +67,8 @@ public void testFromRequest() {
 
         params.put("index", index);
         params.put("local", String.valueOf(local));
-        params.put("master_timeout", masterTimeout);
+        params.put("ensure_node_weighed_in", String.valueOf(ensureLocalWeighedIn));
+        params.put("cluster_manager_timeout", clusterManagerTimeout);
         params.put("timeout", timeout);
         params.put("wait_for_status", waitForStatus.name());
         if (waitForNoRelocatingShards || randomBoolean()) {
@@ -81,7 +86,8 @@ public void testFromRequest() {
         assertThat(clusterHealthRequest.indices().length, equalTo(1));
         assertThat(clusterHealthRequest.indices()[0], equalTo(index));
         assertThat(clusterHealthRequest.local(), equalTo(local));
-        assertThat(clusterHealthRequest.masterNodeTimeout(), equalTo(TimeValue.parseTimeValue(masterTimeout, "test")));
+        assertThat(clusterHealthRequest.ensureNodeWeighedIn(), equalTo(ensureLocalWeighedIn));
+        assertThat(clusterHealthRequest.clusterManagerNodeTimeout(), equalTo(TimeValue.parseTimeValue(clusterManagerTimeout, "test")));
         assertThat(clusterHealthRequest.timeout(), equalTo(TimeValue.parseTimeValue(timeout, "test")));
         assertThat(clusterHealthRequest.waitForStatus(), equalTo(waitForStatus));
         assertThat(clusterHealthRequest.waitForNoRelocatingShards(), equalTo(waitForNoRelocatingShards));
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDecommissionActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDecommissionActionTests.java
new file mode 100644
index 0000000000000..b6adf363ae952
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDecommissionActionTests.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.put.DecommissionRequest;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.test.rest.FakeRestRequest;
+import org.opensearch.test.rest.RestActionTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class RestDecommissionActionTests extends RestActionTestCase {
+
+    private RestDecommissionAction action;
+
+    @Before
+    public void setupAction() {
+        action = new RestDecommissionAction();
+        controller().registerHandler(action);
+    }
+
+    public void testCreateRequest() throws IOException {
+        Map<String, String> params = new HashMap<>();
+        params.put("awareness_attribute_name", "zone");
+        params.put("awareness_attribute_value", "zone-1");
+        params.put("draining_timeout", "60s");
+
+        RestRequest deprecatedRequest = buildRestRequest(params);
+
+        DecommissionRequest request = action.createRequest(deprecatedRequest);
+        assertEquals(request.getDecommissionAttribute().attributeName(), "zone");
+        assertEquals(request.getDecommissionAttribute().attributeValue(), "zone-1");
+        assertEquals(request.getDelayTimeout().getSeconds(), 120);
+        assertEquals(deprecatedRequest.getHttpRequest().method(), RestRequest.Method.PUT);
+    }
+
+    public void testCreateRequestWithDefaultTimeout() throws IOException {
+        Map<String, String> params = new HashMap<>();
+        params.put("awareness_attribute_name", "zone");
+        params.put("awareness_attribute_value", "zone-1");
+
+        RestRequest deprecatedRequest = buildRestRequest(params);
+
+        DecommissionRequest request = action.createRequest(deprecatedRequest);
+        assertEquals(request.getDecommissionAttribute().attributeName(), "zone");
+        assertEquals(request.getDecommissionAttribute().attributeValue(), "zone-1");
+        assertEquals(request.getDelayTimeout().getSeconds(), DecommissionRequest.DEFAULT_NODE_DRAINING_TIMEOUT.getSeconds());
+        assertEquals(deprecatedRequest.getHttpRequest().method(), RestRequest.Method.PUT);
+    }
+
+    public void testCreateRequestWithNoDelay() throws IOException {
+        Map<String, String> params = new HashMap<>();
+        params.put("awareness_attribute_name", "zone");
+        params.put("awareness_attribute_value", "zone-1");
+        params.put("no_delay", "true");
+
+        RestRequest deprecatedRequest = buildRestRequest(params);
+
+        DecommissionRequest request = action.createRequest(deprecatedRequest);
+        assertEquals(request.getDecommissionAttribute().attributeName(), "zone");
+        assertEquals(request.getDecommissionAttribute().attributeValue(), "zone-1");
+        assertEquals(request.getDelayTimeout().getSeconds(), 0);
+        assertEquals(deprecatedRequest.getHttpRequest().method(), RestRequest.Method.PUT);
+    }
+
+    public void testCreateRequestWithDelayTimeout() throws IOException {
+        Map<String, String> params = new HashMap<>();
+        params.put("awareness_attribute_name", "zone");
+        params.put("awareness_attribute_value", "zone-1");
+        params.put("delay_timeout", "300s");
+
+        RestRequest deprecatedRequest = buildRestRequest(params);
+
+        DecommissionRequest request = action.createRequest(deprecatedRequest);
+        assertEquals(request.getDecommissionAttribute().attributeName(), "zone");
+        assertEquals(request.getDecommissionAttribute().attributeValue(), "zone-1");
+        assertEquals(request.getDelayTimeout().getSeconds(), 300);
+        assertEquals(deprecatedRequest.getHttpRequest().method(), RestRequest.Method.PUT);
+    }
+
+    private FakeRestRequest buildRestRequest(Map<String, String> params) {
+        return new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.PUT)
+            .withPath("/_cluster/decommission/awareness/{awareness_attribute_name}/{awareness_attribute_value}")
+            .withParams(params)
+            .build();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateActionTests.java
new file mode 100644
index 0000000000000..6fbf094e6a6be
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestDeleteDecommissionStateActionTests.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.admin.cluster;
+
+import org.opensearch.action.admin.cluster.decommission.awareness.delete.DeleteDecommissionStateRequest;
+import org.opensearch.rest.RestHandler;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.test.rest.RestActionTestCase;
+import org.junit.Before;
+
+import java.util.List;
+
+public class RestDeleteDecommissionStateActionTests extends RestActionTestCase {
+
+    private RestDeleteDecommissionStateAction action;
+
+    @Before
+    public void setupAction() {
+        action = new RestDeleteDecommissionStateAction();
+        controller().registerHandler(action);
+    }
+
+    public void testRoutes() {
+        List<RestHandler.Route> routes = action.routes();
+        RestHandler.Route route = routes.get(0);
+        assertEquals(route.getMethod(), RestRequest.Method.DELETE);
+        assertEquals("/_cluster/decommission/awareness", route.getPath());
+    }
+
+    public void testCreateRequest() {
+        DeleteDecommissionStateRequest request = action.createRequest();
+        assertNotNull(request);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoActionTests.java
index 4d35098309b0d..fb633f9fa4a9c 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestNodesInfoActionTests.java
@@ -54,11 +54,11 @@ public class RestNodesInfoActionTests extends OpenSearchTestCase {
 
     public void testDuplicatedFiltersAreNotRemoved() {
         Map<String, String> params = new HashMap<>();
-        params.put("nodeId", "_all,master:false,_all");
+        params.put("nodeId", "_all,cluster_manager:false,_all");
 
         RestRequest restRequest = buildRestRequest(params);
         NodesInfoRequest actual = RestNodesInfoAction.prepareRequest(restRequest);
-        assertArrayEquals(new String[] { "_all", "master:false", "_all" }, actual.nodesIds());
+        assertArrayEquals(new String[] { "_all", "cluster_manager:false", "_all" }, actual.nodesIds());
     }
 
     public void testOnlyMetrics() {
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsActionTests.java
index 7262fd3c03d93..e976886458f05 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/cluster/RestReloadSecureSettingsActionTests.java
@@ -33,10 +33,10 @@
 package org.opensearch.rest.action.admin.cluster;
 
 import org.opensearch.action.admin.cluster.node.reload.NodesReloadSecureSettingsRequest;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.nullValue;
@@ -46,7 +46,7 @@ public class RestReloadSecureSettingsActionTests extends OpenSearchTestCase {
     public void testParserWithPassword() throws Exception {
         final String request = "{" + "\"secure_settings_password\": \"secure_settings_password_string\"" + "}";
         try (
-            XContentParser parser = XContentType.JSON.xContent()
+            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, request)
         ) {
             NodesReloadSecureSettingsRequest reloadSecureSettingsRequest = RestReloadSecureSettingsAction.PARSER.parse(parser, null);
@@ -57,7 +57,7 @@ public void testParserWithPassword() throws Exception {
     public void testParserWithoutPassword() throws Exception {
         final String request = "{" + "}";
         try (
-            XContentParser parser = XContentType.JSON.xContent()
+            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, request)
         ) {
             NodesReloadSecureSettingsRequest reloadSecureSettingsRequest = RestReloadSecureSettingsAction.PARSER.parse(parser, null);
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestAnalyzeActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestAnalyzeActionTests.java
index 4ece807b314aa..9e3af600706b4 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestAnalyzeActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestAnalyzeActionTests.java
@@ -33,10 +33,10 @@
 
 import org.opensearch.action.admin.indices.analyze.AnalyzeAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.analysis.NameOrDefinition;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.test.OpenSearchTestCase;
@@ -118,7 +118,7 @@ public void testParseXContentForAnalyzeRequestWithInvalidJsonThrowsException() {
         RestAnalyzeAction action = new RestAnalyzeAction();
         RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray("{invalid_json}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         try (NodeClient client = new NoOpNodeClient(this.getClass().getSimpleName())) {
             IOException e = expectThrows(IOException.class, () -> action.handleRequest(request, null, client));
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestCreateIndexActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestCreateIndexActionTests.java
index 707210abad948..ebf921b17a536 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestCreateIndexActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestCreateIndexActionTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.rest.action.admin.indices;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestGetAliasesActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestGetAliasesActionTests.java
index 5dedf39414d75..d326515edf5fb 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestGetAliasesActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestGetAliasesActionTests.java
@@ -33,18 +33,18 @@
 package org.opensearch.rest.action.admin.indices;
 
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
-import static org.opensearch.rest.RestStatus.OK;
-import static org.opensearch.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.NOT_FOUND;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.hamcrest.Matchers.equalTo;
 
 public class RestGetAliasesActionTests extends OpenSearchTestCase {
@@ -59,29 +59,24 @@ public class RestGetAliasesActionTests extends OpenSearchTestCase {
     // }'
 
     public void testBareRequest() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final AliasMetadata foobarAliasMetadata = AliasMetadata.builder("foobar").build();
         final AliasMetadata fooAliasMetadata = AliasMetadata.builder("foo").build();
         openMapBuilder.put("index", Arrays.asList(fooAliasMetadata, foobarAliasMetadata));
-        final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
-            false,
-            new String[0],
-            openMapBuilder.build(),
-            xContentBuilder
-        );
+        final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(false, new String[0], openMapBuilder, xContentBuilder);
         assertThat(restResponse.status(), equalTo(OK));
         assertThat(restResponse.contentType(), equalTo("application/json; charset=UTF-8"));
         assertThat(restResponse.content().utf8ToString(), equalTo("{\"index\":{\"aliases\":{\"foo\":{},\"foobar\":{}}}}"));
     }
 
     public void testSimpleAliasWildcardMatchingNothing() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
             true,
             new String[] { "baz*" },
-            openMapBuilder.build(),
+            openMapBuilder,
             xContentBuilder
         );
         assertThat(restResponse.status(), equalTo(OK));
@@ -90,14 +85,14 @@ public void testSimpleAliasWildcardMatchingNothing() throws Exception {
     }
 
     public void testMultipleAliasWildcardsSomeMatching() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final AliasMetadata aliasMetadata = AliasMetadata.builder("foobar").build();
         openMapBuilder.put("index", Arrays.asList(aliasMetadata));
         final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
             true,
             new String[] { "baz*", "foobar*" },
-            openMapBuilder.build(),
+            openMapBuilder,
             xContentBuilder
         );
         assertThat(restResponse.status(), equalTo(OK));
@@ -106,12 +101,12 @@ public void testMultipleAliasWildcardsSomeMatching() throws Exception {
     }
 
     public void testAliasWildcardsIncludeAndExcludeAll() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
             true,
             new String[] { "foob*", "-foo*" },
-            openMapBuilder.build(),
+            openMapBuilder,
             xContentBuilder
         );
         assertThat(restResponse.status(), equalTo(OK));
@@ -120,14 +115,14 @@ public void testAliasWildcardsIncludeAndExcludeAll() throws Exception {
     }
 
     public void testAliasWildcardsIncludeAndExcludeSome() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final AliasMetadata aliasMetadata = AliasMetadata.builder("foo").build();
         openMapBuilder.put("index", Arrays.asList(aliasMetadata));
         final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
             true,
             new String[] { "foo*", "-foob*" },
-            openMapBuilder.build(),
+            openMapBuilder,
             xContentBuilder
         );
         assertThat(restResponse.status(), equalTo(OK));
@@ -136,8 +131,8 @@ public void testAliasWildcardsIncludeAndExcludeSome() throws Exception {
     }
 
     public void testAliasWildcardsIncludeAndExcludeSomeAndExplicitMissing() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final AliasMetadata aliasMetadata = AliasMetadata.builder("foo").build();
         openMapBuilder.put("index", Arrays.asList(aliasMetadata));
         final String[] aliasPattern;
@@ -147,12 +142,7 @@ public void testAliasWildcardsIncludeAndExcludeSomeAndExplicitMissing() throws E
             aliasPattern = new String[] { "foo*", "-foob*", "missing" };
         }
 
-        final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
-            true,
-            aliasPattern,
-            openMapBuilder.build(),
-            xContentBuilder
-        );
+        final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(true, aliasPattern, openMapBuilder, xContentBuilder);
         assertThat(restResponse.status(), equalTo(NOT_FOUND));
         assertThat(restResponse.contentType(), equalTo("application/json; charset=UTF-8"));
         assertThat(
@@ -162,12 +152,12 @@ public void testAliasWildcardsIncludeAndExcludeSomeAndExplicitMissing() throws E
     }
 
     public void testAliasWildcardsExcludeExplicitMissing() throws Exception {
-        final XContentBuilder xContentBuilder = XContentFactory.contentBuilder(XContentType.JSON);
-        final ImmutableOpenMap.Builder<String, List<AliasMetadata>> openMapBuilder = ImmutableOpenMap.builder();
+        final XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON);
+        final Map<String, List<AliasMetadata>> openMapBuilder = new HashMap<>();
         final RestResponse restResponse = RestGetAliasesAction.buildRestResponse(
             true,
             new String[] { "foo", "foofoo", "-foo*" },
-            openMapBuilder.build(),
+            openMapBuilder,
             xContentBuilder
         );
         assertThat(restResponse.status(), equalTo(OK));
diff --git a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestValidateQueryActionTests.java b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestValidateQueryActionTests.java
index cc1a9d4fd2e40..3fb6764846da6 100644
--- a/server/src/test/java/org/opensearch/rest/action/admin/indices/RestValidateQueryActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/admin/indices/RestValidateQueryActionTests.java
@@ -31,18 +31,20 @@
 
 package org.opensearch.rest.action.admin.indices;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.indices.validate.query.ValidateQueryAction;
 import org.opensearch.action.support.ActionFilters;
 import org.opensearch.action.support.TransportAction;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.rest.RestController;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.search.AbstractSearchTestCase;
@@ -59,6 +61,7 @@
 
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import static java.util.Collections.emptyMap;
@@ -72,7 +75,15 @@ public class RestValidateQueryActionTests extends AbstractSearchTestCase {
     private static NodeClient client = new NodeClient(Settings.EMPTY, threadPool);
 
     private static UsageService usageService = new UsageService();
-    private static RestController controller = new RestController(emptySet(), null, client, new NoneCircuitBreakerService(), usageService);
+    private static IdentityService identityService = new IdentityService(Settings.EMPTY, List.of());
+    private static RestController controller = new RestController(
+        emptySet(),
+        null,
+        client,
+        new NoneCircuitBreakerService(),
+        usageService,
+        identityService
+    );
     private static RestValidateQueryAction action = new RestValidateQueryAction();
 
     /**
@@ -84,7 +95,7 @@ public class RestValidateQueryActionTests extends AbstractSearchTestCase {
     public static void stubValidateQueryAction() {
         final TaskManager taskManager = new TaskManager(Settings.EMPTY, threadPool, Collections.emptySet());
 
-        final TransportAction transportAction = new TransportAction(
+        final TransportAction<?, ?> transportAction = new TransportAction<>(
             ValidateQueryAction.NAME,
             new ActionFilters(Collections.emptySet()),
             taskManager
@@ -96,7 +107,9 @@ protected void doExecute(Task task, ActionRequest request, ActionListener listen
         final Map<ActionType, TransportAction> actions = new HashMap<>();
         actions.put(ValidateQueryAction.INSTANCE, transportAction);
 
-        client.initialize(actions, () -> "local", null, new NamedWriteableRegistry(Collections.emptyList()));
+        DynamicActionRegistry dynamicActionRegistry = new DynamicActionRegistry();
+        dynamicActionRegistry.registerUnmodifiableActionMap(actions);
+        client.initialize(dynamicActionRegistry, () -> "local", null, new NamedWriteableRegistry(Collections.emptyList()));
         controller.registerHandler(action);
     }
 
@@ -169,7 +182,7 @@ public void testRestValidateQueryAction_malformedQuery() throws Exception {
     private RestRequest createRestRequest(String content) {
         return new FakeRestRequest.Builder(xContentRegistry()).withPath("index1/type1/_validate/query")
             .withParams(emptyMap())
-            .withContent(new BytesArray(content), XContentType.JSON)
+            .withContent(new BytesArray(content), MediaTypeRegistry.JSON)
             .build();
     }
 }
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationActionTests.java
new file mode 100644
index 0000000000000..41ad9e8bcbb44
--- /dev/null
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestCatSegmentReplicationActionTests.java
@@ -0,0 +1,190 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.rest.action.cat;
+
+import org.opensearch.action.admin.indices.replication.SegmentReplicationStatsResponse;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.AllocationId;
+import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.Randomness;
+import org.opensearch.common.Table;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.index.SegmentReplicationPerGroupStats;
+import org.opensearch.index.SegmentReplicationShardStats;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationTimer;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+import static java.util.Arrays.asList;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class RestCatSegmentReplicationActionTests extends OpenSearchTestCase {
+    public void testSegmentReplicationAction() throws IOException {
+        final RestCatSegmentReplicationAction action = new RestCatSegmentReplicationAction();
+        final int totalShards = randomIntBetween(1, 32);
+        final int successfulShards = Math.max(0, totalShards - randomIntBetween(1, 2));
+        final int failedShards = totalShards - successfulShards;
+        final Map<String, List<SegmentReplicationPerGroupStats>> shardSegmentReplicationStates = new HashMap<>();
+        final List<SegmentReplicationPerGroupStats> groupStats = new ArrayList<>();
+        final long rejectedRequestCount = 5L;
+
+        for (int i = 0; i < successfulShards; i++) {
+            final ShardId shardId = new ShardId(new Index("index", "_na_"), i);
+            final SegmentReplicationState state = mock(SegmentReplicationState.class);
+            final ShardRouting shardRouting = mock(ShardRouting.class);
+            when(state.getShardRouting()).thenReturn(shardRouting);
+
+            when(shardRouting.shardId()).thenReturn(shardId);
+            final AllocationId aId = mock(AllocationId.class);
+            when(aId.getId()).thenReturn(UUID.randomUUID().toString());
+            when(shardRouting.allocationId()).thenReturn(aId);
+            when(state.getReplicationId()).thenReturn(randomLongBetween(0, 1000));
+            final ReplicationTimer timer = mock(ReplicationTimer.class);
+            final long startTime = randomLongBetween(0, new Date().getTime());
+            when(timer.startTime()).thenReturn(startTime);
+            final long time = randomLongBetween(1000000, 10 * 1000000);
+            when(timer.time()).thenReturn(time);
+            when(timer.stopTime()).thenReturn(startTime + time);
+            when(state.getTimer()).thenReturn(timer);
+            when(state.getStage()).thenReturn(randomFrom(SegmentReplicationState.Stage.values()));
+            when(state.getSourceDescription()).thenReturn("Source");
+            final DiscoveryNode targetNode = mock(DiscoveryNode.class);
+            when(targetNode.getHostName()).thenReturn(randomAlphaOfLength(8));
+            when(targetNode.getName()).thenReturn(UUID.randomUUID().toString());
+            when(state.getTargetNode()).thenReturn(targetNode);
+
+            ReplicationLuceneIndex index = createTestIndex();
+            when(state.getIndex()).thenReturn(index);
+
+            final SegmentReplicationShardStats segmentReplicationShardStats = new SegmentReplicationShardStats(
+                state.getShardRouting().allocationId().getId(),
+                0L,
+                0L,
+                0L,
+                0L,
+                0L
+            );
+            segmentReplicationShardStats.setCurrentReplicationState(state);
+            final SegmentReplicationPerGroupStats perGroupStats = new SegmentReplicationPerGroupStats(
+                shardId,
+                Set.of(segmentReplicationShardStats),
+                rejectedRequestCount
+            );
+            groupStats.add(perGroupStats);
+        }
+
+        Randomness.shuffle(groupStats);
+        shardSegmentReplicationStates.put("index", groupStats);
+
+        final List<DefaultShardOperationFailedException> shardFailures = new ArrayList<>();
+        final SegmentReplicationStatsResponse response = new SegmentReplicationStatsResponse(
+            totalShards,
+            successfulShards,
+            failedShards,
+            shardSegmentReplicationStates,
+            shardFailures
+        );
+        final Table table = action.buildSegmentReplicationTable(null, response);
+
+        assertNotNull(table);
+
+        List<Table.Cell> headers = table.getHeaders();
+
+        final List<String> expectedHeaders = asList(
+            "shardId",
+            "target_node",
+            "target_host",
+            "checkpoints_behind",
+            "bytes_behind",
+            "current_lag",
+            "last_completed_lag",
+            "rejected_requests"
+        );
+
+        for (int i = 0; i < expectedHeaders.size(); i++) {
+            assertThat(headers.get(i).value, equalTo(expectedHeaders.get(i)));
+        }
+
+        assertThat(table.getRows().size(), equalTo(successfulShards));
+
+        for (int i = 0; i < successfulShards; i++) {
+            final SegmentReplicationPerGroupStats perGroupStats = groupStats.get(i);
+            final Set<SegmentReplicationShardStats> replicaStats = perGroupStats.getReplicaStats();
+            assertEquals(1, replicaStats.size());
+            final SegmentReplicationShardStats shardStats = replicaStats.stream().findFirst().get();
+            final SegmentReplicationState currentReplicationState = shardStats.getCurrentReplicationState();
+            final List<Object> expectedValues = asList(
+                perGroupStats.getShardId(),
+                currentReplicationState.getTargetNode().getName(),
+                currentReplicationState.getTargetNode().getHostName(),
+                shardStats.getCheckpointsBehindCount(),
+                new ByteSizeValue(shardStats.getBytesBehindCount()),
+                new TimeValue(shardStats.getCurrentReplicationLagMillis()),
+                new TimeValue(shardStats.getLastCompletedReplicationTimeMillis()),
+                rejectedRequestCount
+            );
+
+            final List<Table.Cell> cells = table.getRows().get(i);
+            for (int j = 0; j < expectedValues.size(); j++) {
+                assertThat(cells.get(j).value, equalTo(expectedValues.get(j)));
+            }
+        }
+    }
+
+    private ReplicationLuceneIndex createTestIndex() {
+        ReplicationLuceneIndex index = new ReplicationLuceneIndex();
+        final int filesToRecoverCount = randomIntBetween(1, 64);
+        final int recoveredFilesCount = randomIntBetween(0, filesToRecoverCount);
+        addTestFileMetadata(index, 0, recoveredFilesCount, false, true);
+        addTestFileMetadata(index, recoveredFilesCount, filesToRecoverCount, false, false);
+
+        final int totalFilesCount = randomIntBetween(filesToRecoverCount, 2 * filesToRecoverCount);
+        addTestFileMetadata(index, filesToRecoverCount, totalFilesCount, true, false);
+        return index;
+    }
+
+    private void addTestFileMetadata(ReplicationLuceneIndex index, int startIndex, int endIndex, boolean reused, boolean isFullyRecovered) {
+        for (int i = startIndex; i < endIndex; i++) {
+            final int completeFileSize = randomIntBetween(1, 1024);
+            index.addFileDetail(String.valueOf(i), completeFileSize, reused);
+
+            if (!reused) {
+                final int recoveredFileSize;
+                if (isFullyRecovered) {
+                    recoveredFileSize = completeFileSize;
+
+                } else {
+                    recoveredFileSize = randomIntBetween(0, completeFileSize);
+                }
+                index.addRecoveredBytesToFile(String.valueOf(i), recoveredFileSize);
+            }
+        }
+    }
+
+    private static String percent(float percent) {
+        return String.format(Locale.ROOT, "%1.1f%%", percent);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestIndicesActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestIndicesActionTests.java
index 9c186e7fde314..96b1c75371697 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestIndicesActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestIndicesActionTests.java
@@ -44,9 +44,9 @@
 import org.opensearch.common.Table;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
 
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestNodesActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestNodesActionTests.java
index 9293d40605f42..6485ddd3bbc94 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestNodesActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestNodesActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.rest.action.cat;
 
-import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
@@ -41,7 +40,10 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.cluster.node.DiscoveryNodeRoleGenerator;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.Table;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.FakeRestRequest;
@@ -49,10 +51,14 @@
 import org.junit.Before;
 
 import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
-import static org.hamcrest.CoreMatchers.containsString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -66,18 +72,15 @@ public void setUpAction() {
     }
 
     public void testBuildTableDoesNotThrowGivenNullNodeInfoAndStats() {
-        ClusterName clusterName = new ClusterName("cluster-1");
-        DiscoveryNodes.Builder builder = DiscoveryNodes.builder();
-        builder.add(new DiscoveryNode("node-1", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT));
-        DiscoveryNodes discoveryNodes = builder.build();
-        ClusterState clusterState = mock(ClusterState.class);
-        when(clusterState.nodes()).thenReturn(discoveryNodes);
-
-        ClusterStateResponse clusterStateResponse = new ClusterStateResponse(clusterName, clusterState, false);
-        NodesInfoResponse nodesInfoResponse = new NodesInfoResponse(clusterName, Collections.emptyList(), Collections.emptyList());
-        NodesStatsResponse nodesStatsResponse = new NodesStatsResponse(clusterName, Collections.emptyList(), Collections.emptyList());
-
-        action.buildTable(false, new FakeRestRequest(), clusterStateResponse, nodesInfoResponse, nodesStatsResponse);
+        testBuildTableWithRoles(emptySet(), (table) -> {
+            Map<String, List<Table.Cell>> nodeInfoMap = table.getAsMap();
+            List<Table.Cell> cells = nodeInfoMap.get("node.role");
+            assertEquals(1, cells.size());
+            assertEquals("-", cells.get(0).value);
+            cells = nodeInfoMap.get("node.roles");
+            assertEquals(1, cells.size());
+            assertEquals("-", cells.get(0).value);
+        });
     }
 
     public void testCatNodesWithLocalDeprecationWarning() {
@@ -92,19 +95,50 @@ public void testCatNodesWithLocalDeprecationWarning() {
         terminate(threadPool);
     }
 
-    /**
-     * Validate both cluster_manager_timeout and its predecessor can be parsed correctly.
-     * Remove the test along with MASTER_ROLE. It's added in version 2.0.0.
-     */
-    public void testCatNodesWithClusterManagerTimeout() {
-        TestThreadPool threadPool = new TestThreadPool(RestNodesActionTests.class.getName());
-        NodeClient client = new NodeClient(Settings.EMPTY, threadPool);
-        FakeRestRequest request = new FakeRestRequest();
-        request.params().put("cluster_manager_timeout", randomFrom("1h", "2m"));
-        request.params().put("master_timeout", "3s");
-        Exception e = assertThrows(OpenSearchParseException.class, () -> action.doCatRequest(request, client));
-        assertThat(e.getMessage(), containsString("[master_timeout, cluster_manager_timeout] are required to be equal"));
-        assertWarnings(RestNodesAction.MASTER_TIMEOUT_DEPRECATED_MESSAGE);
-        terminate(threadPool);
+    public void testBuildTableWithDynamicRoleOnly() {
+        Set<DiscoveryNodeRole> roles = new HashSet<>();
+        String roleName = "test_role";
+        DiscoveryNodeRole testRole = DiscoveryNodeRoleGenerator.createDynamicRole(roleName);
+        roles.add(testRole);
+
+        testBuildTableWithRoles(roles, (table) -> {
+            Map<String, List<Table.Cell>> nodeInfoMap = table.getAsMap();
+            List<Table.Cell> cells = nodeInfoMap.get("node.roles");
+            assertEquals(1, cells.size());
+            assertEquals(roleName, cells.get(0).value);
+        });
+    }
+
+    public void testBuildTableWithBothBuiltInAndDynamicRoles() {
+        Set<DiscoveryNodeRole> roles = new HashSet<>();
+        roles.add(DiscoveryNodeRole.DATA_ROLE);
+        String roleName = "test_role";
+        DiscoveryNodeRole testRole = DiscoveryNodeRoleGenerator.createDynamicRole(roleName);
+        roles.add(testRole);
+
+        testBuildTableWithRoles(roles, (table) -> {
+            Map<String, List<Table.Cell>> nodeInfoMap = table.getAsMap();
+            List<Table.Cell> cells = nodeInfoMap.get("node.roles");
+            assertEquals(1, cells.size());
+            assertEquals("data,test_role", cells.get(0).value);
+        });
+    }
+
+    private void testBuildTableWithRoles(Set<DiscoveryNodeRole> roles, Consumer<Table> verificationFunction) {
+        ClusterName clusterName = new ClusterName("cluster-1");
+        DiscoveryNodes.Builder builder = DiscoveryNodes.builder();
+
+        builder.add(new DiscoveryNode("node-1", buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT));
+        DiscoveryNodes discoveryNodes = builder.build();
+        ClusterState clusterState = mock(ClusterState.class);
+        when(clusterState.nodes()).thenReturn(discoveryNodes);
+
+        ClusterStateResponse clusterStateResponse = new ClusterStateResponse(clusterName, clusterState, false);
+        NodesInfoResponse nodesInfoResponse = new NodesInfoResponse(clusterName, Collections.emptyList(), Collections.emptyList());
+        NodesStatsResponse nodesStatsResponse = new NodesStatsResponse(clusterName, Collections.emptyList(), Collections.emptyList());
+
+        Table table = action.buildTable(false, new FakeRestRequest(), clusterStateResponse, nodesInfoResponse, nodesStatsResponse);
+
+        verificationFunction.accept(table);
     }
 }
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestRecoveryActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestRecoveryActionTests.java
index 7966d2961c29a..e0b3847cda571 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestRecoveryActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestRecoveryActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.rest.action.cat;
 
 import org.opensearch.action.admin.indices.recovery.RecoveryResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
@@ -42,9 +41,12 @@
 import org.opensearch.common.Table;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentOpenSearchExtension;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.common.ReplicationLuceneIndex;
+import org.opensearch.indices.replication.common.ReplicationTimer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
@@ -72,7 +74,7 @@ public void testRestRecoveryAction() {
         for (int i = 0; i < successfulShards; i++) {
             final RecoveryState state = mock(RecoveryState.class);
             when(state.getShardId()).thenReturn(new ShardId(new Index("index", "_na_"), i));
-            final RecoveryState.Timer timer = mock(RecoveryState.Timer.class);
+            final ReplicationTimer timer = mock(ReplicationTimer.class);
             final long startTime = randomLongBetween(0, new Date().getTime());
             when(timer.startTime()).thenReturn(startTime);
             final long time = randomLongBetween(1000000, 10 * 1000000);
@@ -90,21 +92,7 @@ public void testRestRecoveryAction() {
             when(targetNode.getHostName()).thenReturn(randomAlphaOfLength(8));
             when(state.getTargetNode()).thenReturn(targetNode);
 
-            RecoveryState.Index index = mock(RecoveryState.Index.class);
-
-            final int totalRecoveredFiles = randomIntBetween(1, 64);
-            when(index.totalRecoverFiles()).thenReturn(totalRecoveredFiles);
-            final int recoveredFileCount = randomIntBetween(0, totalRecoveredFiles);
-            when(index.recoveredFileCount()).thenReturn(recoveredFileCount);
-            when(index.recoveredFilesPercent()).thenReturn((100f * recoveredFileCount) / totalRecoveredFiles);
-            when(index.totalFileCount()).thenReturn(randomIntBetween(totalRecoveredFiles, 2 * totalRecoveredFiles));
-
-            final int totalRecoveredBytes = randomIntBetween(1, 1 << 24);
-            when(index.totalRecoverBytes()).thenReturn((long) totalRecoveredBytes);
-            final int recoveredBytes = randomIntBetween(0, totalRecoveredBytes);
-            when(index.recoveredBytes()).thenReturn((long) recoveredBytes);
-            when(index.recoveredBytesPercent()).thenReturn((100f * recoveredBytes) / totalRecoveredBytes);
-            when(index.totalRecoverBytes()).thenReturn((long) randomIntBetween(totalRecoveredBytes, 2 * totalRecoveredBytes));
+            ReplicationLuceneIndex index = createTestIndex();
             when(state.getIndex()).thenReturn(index);
 
             final RecoveryState.Translog translog = mock(RecoveryState.Translog.class);
@@ -213,6 +201,36 @@ public void testRestRecoveryAction() {
         }
     }
 
+    private ReplicationLuceneIndex createTestIndex() {
+        ReplicationLuceneIndex index = new ReplicationLuceneIndex();
+        final int filesToRecoverCount = randomIntBetween(1, 64);
+        final int recoveredFilesCount = randomIntBetween(0, filesToRecoverCount);
+        addTestFileMetadata(index, 0, recoveredFilesCount, false, true);
+        addTestFileMetadata(index, recoveredFilesCount, filesToRecoverCount, false, false);
+
+        final int totalFilesCount = randomIntBetween(filesToRecoverCount, 2 * filesToRecoverCount);
+        addTestFileMetadata(index, filesToRecoverCount, totalFilesCount, true, false);
+        return index;
+    }
+
+    private void addTestFileMetadata(ReplicationLuceneIndex index, int startIndex, int endIndex, boolean reused, boolean isFullyRecovered) {
+        for (int i = startIndex; i < endIndex; i++) {
+            final int completeFileSize = randomIntBetween(1, 1024);
+            index.addFileDetail(String.valueOf(i), completeFileSize, reused);
+
+            if (!reused) {
+                final int recoveredFileSize;
+                if (isFullyRecovered) {
+                    recoveredFileSize = completeFileSize;
+
+                } else {
+                    recoveredFileSize = randomIntBetween(0, completeFileSize);
+                }
+                index.addRecoveredBytesToFile(String.valueOf(i), recoveredFileSize);
+            }
+        }
+    }
+
     private static String percent(float percent) {
         return String.format(Locale.ROOT, "%1.1f%%", percent);
     }
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestShardsActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestShardsActionTests.java
index ed3aa19afa146..a8679a087216d 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestShardsActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestShardsActionTests.java
@@ -134,8 +134,8 @@ public void testBuildTable() {
             assertThat(row.get(3).value, equalTo(shardRouting.state()));
             assertThat(row.get(6).value, equalTo(localNode.getHostAddress()));
             assertThat(row.get(7).value, equalTo(localNode.getId()));
-            assertThat(row.get(69).value, equalTo(shardStats.getDataPath()));
-            assertThat(row.get(70).value, equalTo(shardStats.getStatePath()));
+            assertThat(row.get(72).value, equalTo(shardStats.getDataPath()));
+            assertThat(row.get(73).value, equalTo(shardStats.getStatePath()));
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestTableTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestTableTests.java
index 89fbcf6a3506d..8183cb1d3b910 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestTableTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestTableTests.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.common.Table;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.AbstractRestChannel;
 import org.opensearch.rest.RestResponse;
 import org.opensearch.test.OpenSearchTestCase;
@@ -55,7 +56,7 @@
 
 public class RestTableTests extends OpenSearchTestCase {
 
-    private static final String APPLICATION_JSON = XContentType.JSON.mediaType();
+    private static final String APPLICATION_JSON = MediaTypeRegistry.JSON.mediaType();
     private static final String APPLICATION_YAML = XContentType.YAML.mediaType();
     private static final String APPLICATION_SMILE = XContentType.SMILE.mediaType();
     private static final String APPLICATION_CBOR = XContentType.CBOR.mediaType();
diff --git a/server/src/test/java/org/opensearch/rest/action/cat/RestTasksActionTests.java b/server/src/test/java/org/opensearch/rest/action/cat/RestTasksActionTests.java
index 819ab5b334e43..aaa5c5534d5c0 100644
--- a/server/src/test/java/org/opensearch/rest/action/cat/RestTasksActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/cat/RestTasksActionTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.rest.action.cat;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.collect.MapBuilder;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.client.NoOpNodeClient;
 import org.opensearch.test.rest.FakeRestChannel;
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
index 19fd74aa30c07..55d7103724072 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.rest.action.document;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.RestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.test.OpenSearchTestCase;
@@ -82,7 +82,7 @@ public void bulk(BulkRequest request, ActionListener<BulkResponse> listener) {
                                 + "{\"update\":{\"_id\":\"2\"}}\n"
                                 + "{\"script\":{\"source\":\"ctx._source.counter++;\"},\"upsert\":{\"field1\":\"upserted_val\"}}\n"
                         ),
-                        XContentType.JSON
+                        MediaTypeRegistry.JSON
                     )
                     .withMethod(RestRequest.Method.POST)
                     .build(),
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestGetSourceActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestGetSourceActionTests.java
index ca6ecd052fe6a..8d797322dc6ab 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestGetSourceActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestGetSourceActionTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.action.get.GetResponse;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.get.GetResult;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
@@ -47,8 +47,8 @@
 import org.junit.Before;
 
 import static java.util.Collections.emptyMap;
+import static org.opensearch.core.rest.RestStatus.OK;
 import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
-import static org.opensearch.rest.RestStatus.OK;
 import static org.hamcrest.Matchers.equalTo;
 
 public class RestGetSourceActionTests extends RestActionTestCase {
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
index 5a1d43ff5dd04..c1221920340f7 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.rest.action.document;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.action.DocWriteRequest;
@@ -41,8 +40,9 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.document.RestIndexAction.AutoIdHandler;
 import org.opensearch.rest.action.document.RestIndexAction.CreateHandler;
@@ -113,7 +113,7 @@ private void checkAutoIdOpType(Version minClusterVersion, DocWriteRequest.OpType
         });
         RestRequest autoIdRequest = new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.POST)
             .withPath("/some_index/_doc")
-            .withContent(new BytesArray("{}"), XContentType.JSON)
+            .withContent(new BytesArray("{}"), MediaTypeRegistry.JSON)
             .build();
         clusterStateSupplier.set(
             ClusterState.builder(ClusterName.DEFAULT)
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestUpdateActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestUpdateActionTests.java
index bf544acf13508..67f45467d0052 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestUpdateActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestUpdateActionTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.VersionType;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.test.rest.FakeRestRequest;
@@ -72,7 +72,7 @@ public void testUpdateDocVersion() {
         FakeRestRequest updateRequest = new FakeRestRequest.Builder(xContentRegistry()).withMethod(RestRequest.Method.POST)
             .withPath("test/_update/1")
             .withParams(params)
-            .withContent(new BytesArray(content), XContentType.JSON)
+            .withContent(new BytesArray(content), MediaTypeRegistry.JSON)
             .build();
         ActionRequestValidationException e = expectThrows(
             ActionRequestValidationException.class,
diff --git a/server/src/test/java/org/opensearch/script/ScriptCacheTests.java b/server/src/test/java/org/opensearch/script/ScriptCacheTests.java
index 32e1c65cedbad..99eedb39e7381 100644
--- a/server/src/test/java/org/opensearch/script/ScriptCacheTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptCacheTests.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/script/ScriptContextInfoTests.java b/server/src/test/java/org/opensearch/script/ScriptContextInfoTests.java
index cd0807d703b3c..13e353126f0c3 100644
--- a/server/src/test/java/org/opensearch/script/ScriptContextInfoTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptContextInfoTests.java
@@ -32,14 +32,14 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.script.ScriptContextInfo.ScriptMethodInfo;
 import org.opensearch.script.ScriptContextInfo.ScriptMethodInfo.ParameterInfo;
 import org.opensearch.test.OpenSearchTestCase;
@@ -317,7 +317,7 @@ public void testGetterConditional() {
     public void testParameterInfoParser() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
 
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -330,7 +330,7 @@ public void testParameterInfoParser() throws IOException {
     public void testScriptMethodInfoParser() throws IOException {
         String json = "{\"name\": \"fooFunc\", \"return_type\": \"int\", \"params\": [{\"type\": \"int\", \"name\": \"fooParam\"}, "
             + "{\"type\": \"java.util.Map\", \"name\": \"barParam\"}]}";
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, new BytesArray(json).streamInput());
         ScriptContextInfo.ScriptMethodInfo info = ScriptContextInfo.ScriptMethodInfo.fromXContent(parser);
         assertEquals(
@@ -395,7 +395,7 @@ public void testScriptContextInfoParser() throws IOException {
             + "    }"
             + "  ]"
             + "}";
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, new BytesArray(json).streamInput());
         ScriptContextInfo parsed = ScriptContextInfo.fromXContent(parser);
         ScriptContextInfo expected = new ScriptContextInfo(
diff --git a/server/src/test/java/org/opensearch/script/ScriptExceptionTests.java b/server/src/test/java/org/opensearch/script/ScriptExceptionTests.java
index cda79234877ec..bc648ae4b46c7 100644
--- a/server/src/test/java/org/opensearch/script/ScriptExceptionTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptExceptionTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.io.stream.DataOutputStreamOutput;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.DataOutputStreamOutput;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
diff --git a/server/src/test/java/org/opensearch/script/ScriptMetadataTests.java b/server/src/test/java/org/opensearch/script/ScriptMetadataTests.java
index 116beb1b8673e..daf3b7ae1feaa 100644
--- a/server/src/test/java/org/opensearch/script/ScriptMetadataTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptMetadataTests.java
@@ -32,15 +32,17 @@
 package org.opensearch.script;
 
 import org.opensearch.cluster.DiffableUtils;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -53,7 +55,7 @@ public void testFromXContentLoading() throws Exception {
         // failure to load to old namespace scripts with the same id but different langs
         XContentBuilder builder = XContentFactory.jsonBuilder();
         builder.startObject().field("lang0#id0", "script0").field("lang1#id0", "script1").endObject();
-        XContentParser parser0 = XContentType.JSON.xContent()
+        XContentParser parser0 = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -70,7 +72,7 @@ public void testFromXContentLoading() throws Exception {
             .field("source", "script1")
             .endObject()
             .endObject();
-        XContentParser parser1 = XContentType.JSON.xContent()
+        XContentParser parser1 = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -92,7 +94,7 @@ public void testFromXContentLoading() throws Exception {
             .field("source", "script1")
             .endObject()
             .endObject();
-        XContentParser parser2 = XContentType.JSON.xContent()
+        XContentParser parser2 = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -109,7 +111,7 @@ public void testFromXContentLoading() throws Exception {
             .field("source", "script1")
             .endObject()
             .endObject();
-        XContentParser parser3 = XContentType.JSON.xContent()
+        XContentParser parser3 = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -130,11 +132,13 @@ public void testGetScript() throws Exception {
             .endObject()
             .endObject()
             .endObject();
-        builder.storeScript("source_template", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), sourceBuilder.contentType()));
+        MediaType mediaType = sourceBuilder.contentType();
+        builder.storeScript("source_template", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), mediaType));
 
         sourceBuilder = XContentFactory.jsonBuilder();
+        mediaType = sourceBuilder.contentType();
         sourceBuilder.startObject().startObject("script").field("lang", "_lang").field("source", "_source").endObject().endObject();
-        builder.storeScript("script", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), sourceBuilder.contentType()));
+        builder.storeScript("script", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), mediaType));
 
         ScriptMetadata scriptMetadata = builder.build();
         assertEquals("_source", scriptMetadata.getStoredScript("script").getSource());
@@ -145,15 +149,24 @@ public void testDiff() throws Exception {
         ScriptMetadata.Builder builder = new ScriptMetadata.Builder(null);
         builder.storeScript(
             "1",
-            StoredScriptSource.parse(new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"abc\"}}}"), XContentType.JSON)
+            StoredScriptSource.parse(
+                new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"abc\"}}}"),
+                MediaTypeRegistry.JSON
+            )
         );
         builder.storeScript(
             "2",
-            StoredScriptSource.parse(new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"def\"}}}"), XContentType.JSON)
+            StoredScriptSource.parse(
+                new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"def\"}}}"),
+                MediaTypeRegistry.JSON
+            )
         );
         builder.storeScript(
             "3",
-            StoredScriptSource.parse(new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"ghi\"}}}"), XContentType.JSON)
+            StoredScriptSource.parse(
+                new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"ghi\"}}}"),
+                MediaTypeRegistry.JSON
+            )
         );
         ScriptMetadata scriptMetadata1 = builder.build();
 
@@ -162,13 +175,16 @@ public void testDiff() throws Exception {
             "2",
             StoredScriptSource.parse(
                 new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"changed\"}}}"),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         builder.deleteScript("3");
         builder.storeScript(
             "4",
-            StoredScriptSource.parse(new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"jkl\"}}}"), XContentType.JSON)
+            StoredScriptSource.parse(
+                new BytesArray("{\"script\":{\"lang\":\"mustache\",\"source\":{\"foo\":\"jkl\"}}}"),
+                MediaTypeRegistry.JSON
+            )
         );
         ScriptMetadata scriptMetadata2 = builder.build();
 
@@ -190,7 +206,10 @@ public void testBuilder() {
         ScriptMetadata.Builder builder = new ScriptMetadata.Builder(null);
         builder.storeScript(
             "_id",
-            StoredScriptSource.parse(new BytesArray("{\"script\": {\"lang\": \"painless\", \"source\": \"1 + 1\"} }"), XContentType.JSON)
+            StoredScriptSource.parse(
+                new BytesArray("{\"script\": {\"lang\": \"painless\", \"source\": \"1 + 1\"} }"),
+                MediaTypeRegistry.JSON
+            )
         );
 
         ScriptMetadata result = builder.build();
@@ -200,7 +219,7 @@ public void testBuilder() {
     public void testLoadEmptyScripts() throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
         builder.startObject().field("mustache#empty", "").endObject();
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -211,7 +230,7 @@ public void testLoadEmptyScripts() throws IOException {
 
         builder = XContentFactory.jsonBuilder();
         builder.startObject().field("lang#empty", "").endObject();
-        parser = XContentType.JSON.xContent()
+        parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -222,7 +241,7 @@ public void testLoadEmptyScripts() throws IOException {
 
         builder = XContentFactory.jsonBuilder();
         builder.startObject().startObject("script").field("lang", "lang").field("source", "").endObject().endObject();
-        parser = XContentType.JSON.xContent()
+        parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -233,7 +252,7 @@ public void testLoadEmptyScripts() throws IOException {
 
         builder = XContentFactory.jsonBuilder();
         builder.startObject().startObject("script").field("lang", "mustache").field("source", "").endObject().endObject();
-        parser = XContentType.JSON.xContent()
+        parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -244,7 +263,7 @@ public void testLoadEmptyScripts() throws IOException {
     }
 
     public void testOldStyleDropped() throws IOException {
-        XContentBuilder builder = XContentBuilder.builder(XContentType.JSON.xContent());
+        XContentBuilder builder = MediaTypeRegistry.JSON.contentBuilder();
 
         builder.startObject();
         {
@@ -269,7 +288,7 @@ public void testOldStyleDropped() throws IOException {
         }
         builder.endObject();
 
-        XContentParser parser = XContentType.JSON.xContent()
+        XContentParser parser = MediaTypeRegistry.JSON.xContent()
             .createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
diff --git a/server/src/test/java/org/opensearch/script/ScriptServiceTests.java b/server/src/test/java/org/opensearch/script/ScriptServiceTests.java
index f5fc62719564f..3007c37027a9c 100644
--- a/server/src/test/java/org/opensearch/script/ScriptServiceTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptServiceTests.java
@@ -36,15 +36,15 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
@@ -60,8 +60,8 @@
 import static org.opensearch.script.ScriptService.SCRIPT_CACHE_EXPIRE_SETTING;
 import static org.opensearch.script.ScriptService.SCRIPT_CACHE_SIZE_SETTING;
 import static org.opensearch.script.ScriptService.SCRIPT_GENERAL_CACHE_EXPIRE_SETTING;
-import static org.opensearch.script.ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING;
 import static org.opensearch.script.ScriptService.SCRIPT_GENERAL_CACHE_SIZE_SETTING;
+import static org.opensearch.script.ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING;
 import static org.opensearch.script.ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.is;
@@ -375,7 +375,11 @@ public void testStoreScript() throws Exception {
                 .endObject()
                 .endObject()
         );
-        ScriptMetadata scriptMetadata = ScriptMetadata.putStoredScript(null, "_id", StoredScriptSource.parse(script, XContentType.JSON));
+        ScriptMetadata scriptMetadata = ScriptMetadata.putStoredScript(
+            null,
+            "_id",
+            StoredScriptSource.parse(script, MediaTypeRegistry.JSON)
+        );
         assertNotNull(scriptMetadata);
         assertEquals("abc", scriptMetadata.getStoredScript("_id").getSource());
     }
@@ -384,17 +388,16 @@ public void testDeleteScript() throws Exception {
         ScriptMetadata scriptMetadata = ScriptMetadata.putStoredScript(
             null,
             "_id",
-            StoredScriptSource.parse(new BytesArray("{\"script\": {\"lang\": \"_lang\", \"source\": \"abc\"} }"), XContentType.JSON)
+            StoredScriptSource.parse(new BytesArray("{\"script\": {\"lang\": \"_lang\", \"source\": \"abc\"} }"), MediaTypeRegistry.JSON)
         );
         scriptMetadata = ScriptMetadata.deleteStoredScript(scriptMetadata, "_id");
         assertNotNull(scriptMetadata);
         assertNull(scriptMetadata.getStoredScript("_id"));
 
         ScriptMetadata errorMetadata = scriptMetadata;
-        ResourceNotFoundException e = expectThrows(
-            ResourceNotFoundException.class,
-            () -> { ScriptMetadata.deleteStoredScript(errorMetadata, "_id"); }
-        );
+        ResourceNotFoundException e = expectThrows(ResourceNotFoundException.class, () -> {
+            ScriptMetadata.deleteStoredScript(errorMetadata, "_id");
+        });
         assertEquals("stored script [_id] does not exist and cannot be deleted", e.getMessage());
     }
 
@@ -409,7 +412,7 @@ public void testGetStoredScript() throws Exception {
                             "_id",
                             StoredScriptSource.parse(
                                 new BytesArray("{\"script\": {\"lang\": \"_lang\", \"source\": \"abc\"} }"),
-                                XContentType.JSON
+                                MediaTypeRegistry.JSON
                             )
                         ).build()
                     )
@@ -425,24 +428,17 @@ public void testGetStoredScript() throws Exception {
     public void testMaxSizeLimit() throws Exception {
         buildScriptService(Settings.builder().put(ScriptService.SCRIPT_MAX_SIZE_IN_BYTES.getKey(), 4).build());
         scriptService.compile(new Script(ScriptType.INLINE, "test", "1+1", Collections.emptyMap()), randomFrom(contexts.values()));
-        IllegalArgumentException iae = expectThrows(
-            IllegalArgumentException.class,
-            () -> {
-                scriptService.compile(
-                    new Script(ScriptType.INLINE, "test", "10+10", Collections.emptyMap()),
-                    randomFrom(contexts.values())
-                );
-            }
-        );
+        IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () -> {
+            scriptService.compile(new Script(ScriptType.INLINE, "test", "10+10", Collections.emptyMap()), randomFrom(contexts.values()));
+        });
         assertEquals("exceeded max allowed inline script size in bytes [4] with size [5] for script [10+10]", iae.getMessage());
         clusterSettings.applySettings(Settings.builder().put(ScriptService.SCRIPT_MAX_SIZE_IN_BYTES.getKey(), 6).build());
         scriptService.compile(new Script(ScriptType.INLINE, "test", "10+10", Collections.emptyMap()), randomFrom(contexts.values()));
         clusterSettings.applySettings(Settings.builder().put(ScriptService.SCRIPT_MAX_SIZE_IN_BYTES.getKey(), 5).build());
         scriptService.compile(new Script(ScriptType.INLINE, "test", "10+10", Collections.emptyMap()), randomFrom(contexts.values()));
-        iae = expectThrows(
-            IllegalArgumentException.class,
-            () -> { clusterSettings.applySettings(Settings.builder().put(ScriptService.SCRIPT_MAX_SIZE_IN_BYTES.getKey(), 2).build()); }
-        );
+        iae = expectThrows(IllegalArgumentException.class, () -> {
+            clusterSettings.applySettings(Settings.builder().put(ScriptService.SCRIPT_MAX_SIZE_IN_BYTES.getKey(), 2).build());
+        });
         assertEquals(
             "script.max_size_in_bytes cannot be set to [2], stored script [test1] exceeds the new value with a size of [3]",
             iae.getMessage()
@@ -537,10 +533,9 @@ public void testUseContextSettingValue() {
 
         assertEquals(ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING.get(s), ScriptService.USE_CONTEXT_RATE_VALUE);
 
-        IllegalArgumentException illegal = expectThrows(
-            IllegalArgumentException.class,
-            () -> { ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getAsMap(s); }
-        );
+        IllegalArgumentException illegal = expectThrows(IllegalArgumentException.class, () -> {
+            ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getAsMap(s);
+        });
 
         assertEquals("parameter must contain a positive integer and a timevalue, i.e. 10/1m, but was [use-context]", illegal.getMessage());
         assertSettingDeprecationsAndWarnings(new Setting<?>[] { SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING });
diff --git a/server/src/test/java/org/opensearch/script/ScriptTests.java b/server/src/test/java/org/opensearch/script/ScriptTests.java
index 9bbc744301ce4..0b871ee4847cc 100644
--- a/server/src/test/java/org/opensearch/script/ScriptTests.java
+++ b/server/src/test/java/org/opensearch/script/ScriptTests.java
@@ -33,16 +33,17 @@
 package org.opensearch.script;
 
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
@@ -58,7 +59,7 @@ public class ScriptTests extends OpenSearchTestCase {
 
     public void testScriptParsing() throws IOException {
         Script expectedScript = createScript();
-        try (XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()))) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()))) {
             expectedScript.toXContent(builder, ToXContent.EMPTY_PARAMS);
             try (XContentParser parser = createParser(builder)) {
                 Script actualScript = Script.parse(parser);
@@ -87,7 +88,7 @@ private Script createScript() throws IOException {
                 builder.startObject();
                 builder.field("field", randomAlphaOfLengthBetween(1, 5));
                 builder.endObject();
-                script = Strings.toString(builder);
+                script = builder.toString();
             }
         } else {
             script = randomAlphaOfLengthBetween(1, 5);
@@ -96,14 +97,16 @@ private Script createScript() throws IOException {
             scriptType,
             scriptType == ScriptType.STORED ? null : randomFrom("_lang1", "_lang2", "_lang3"),
             script,
-            scriptType == ScriptType.INLINE ? Collections.singletonMap(Script.CONTENT_TYPE_OPTION, XContentType.JSON.mediaType()) : null,
+            scriptType == ScriptType.INLINE
+                ? Collections.singletonMap(Script.CONTENT_TYPE_OPTION, MediaTypeRegistry.JSON.mediaType())
+                : null,
             params
         );
     }
 
     public void testParse() throws IOException {
         Script expectedScript = createScript();
-        try (XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()))) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()))) {
             expectedScript.toXContent(builder, ToXContent.EMPTY_PARAMS);
             try (XContentParser xParser = createParser(builder)) {
                 Settings settings = Settings.fromXContent(xParser);
@@ -166,7 +169,11 @@ public void testParseFromObjectFromScript() {
             options.put("option" + i, Integer.toString(i));
         }
         Script script = new Script(ScriptType.INLINE, Script.DEFAULT_SCRIPT_LANG, "doc['field']", options, params);
-        Map<String, Object> scriptObject = XContentHelper.convertToMap(XContentType.JSON.xContent(), Strings.toString(script), false);
+        Map<String, Object> scriptObject = XContentHelper.convertToMap(
+            MediaTypeRegistry.JSON.xContent(),
+            Strings.toString(MediaTypeRegistry.JSON, script),
+            false
+        );
         Script parsedScript = Script.parse(scriptObject);
         assertEquals(script, parsedScript);
     }
diff --git a/server/src/test/java/org/opensearch/script/StoredScriptSourceTests.java b/server/src/test/java/org/opensearch/script/StoredScriptSourceTests.java
index 9cb974627cafa..24c4fddc7dce8 100644
--- a/server/src/test/java/org/opensearch/script/StoredScriptSourceTests.java
+++ b/server/src/test/java/org/opensearch/script/StoredScriptSourceTests.java
@@ -32,12 +32,13 @@
 
 package org.opensearch.script;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -48,9 +49,9 @@ public class StoredScriptSourceTests extends AbstractSerializingTestCase<StoredS
 
     @Override
     protected StoredScriptSource createTestInstance() {
-        XContentType xContentType = randomFrom(XContentType.JSON, XContentType.YAML);
+        MediaType mediaType = randomFrom(MediaTypeRegistry.JSON, XContentType.YAML);
         try {
-            XContentBuilder template = XContentBuilder.builder(xContentType.xContent());
+            XContentBuilder template = XContentBuilder.builder(mediaType.xContent());
             template.startObject();
             template.startObject("script");
             {
@@ -64,9 +65,9 @@ protected StoredScriptSource createTestInstance() {
             template.endObject();
             Map<String, String> options = new HashMap<>();
             if (randomBoolean()) {
-                options.put(Script.CONTENT_TYPE_OPTION, xContentType.mediaType());
+                options.put(Script.CONTENT_TYPE_OPTION, mediaType.mediaType());
             }
-            return StoredScriptSource.parse(BytesReference.bytes(template), xContentType);
+            return StoredScriptSource.parse(BytesReference.bytes(template), mediaType);
         } catch (IOException e) {
             throw new AssertionError("Failed to create test instance", e);
         }
@@ -88,7 +89,7 @@ protected StoredScriptSource mutateInstance(StoredScriptSource instance) throws
         String lang = instance.getLang();
         Map<String, String> options = instance.getOptions();
 
-        XContentType newXContentType = randomFrom(XContentType.JSON, XContentType.YAML);
+        MediaType newXContentType = randomFrom(MediaTypeRegistry.JSON, XContentType.YAML);
         XContentBuilder newTemplate = XContentBuilder.builder(newXContentType.xContent());
         newTemplate.startObject();
         newTemplate.startObject("query");
@@ -100,7 +101,7 @@ protected StoredScriptSource mutateInstance(StoredScriptSource instance) throws
 
         switch (between(0, 2)) {
             case 0:
-                source = Strings.toString(newTemplate);
+                source = newTemplate.toString();
                 break;
             case 1:
                 lang = randomAlphaOfLengthBetween(1, 20);
diff --git a/server/src/test/java/org/opensearch/script/StoredScriptTests.java b/server/src/test/java/org/opensearch/script/StoredScriptTests.java
index fc9e6795106ef..36d9f4dc6e601 100644
--- a/server/src/test/java/org/opensearch/script/StoredScriptTests.java
+++ b/server/src/test/java/org/opensearch/script/StoredScriptTests.java
@@ -33,14 +33,12 @@
 package org.opensearch.script;
 
 import org.opensearch.ResourceNotFoundException;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -73,17 +71,17 @@ public void testInvalidDelete() {
 
     public void testSourceParsing() throws Exception {
         // simple script value string
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().startObject("script").field("lang", "lang").field("source", "code").endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
         }
 
         // complex template using script as the field name
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject()
                 .startObject("script")
                 .field("lang", "mustache")
@@ -94,11 +92,11 @@ public void testSourceParsing() throws Exception {
                 .endObject();
             String code;
 
-            try (XContentBuilder cb = XContentFactory.contentBuilder(builder.contentType())) {
-                code = Strings.toString(cb.startObject().field("query", "code").endObject());
+            try (XContentBuilder cb = MediaTypeRegistry.contentBuilder(builder.contentType())) {
+                code = cb.startObject().field("query", "code").endObject().toString();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource(
                 "mustache",
                 code,
@@ -109,20 +107,20 @@ public void testSourceParsing() throws Exception {
         }
 
         // complex script with script object
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("script").startObject().field("lang", "lang").field("source", "code").endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
         }
 
         // complex script using "code" backcompat
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("script").startObject().field("lang", "lang").field("code", "code").endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
@@ -130,7 +128,7 @@ public void testSourceParsing() throws Exception {
         assertWarnings("Deprecated field [code] used, expected [source] instead");
 
         // complex script with script object and empty options
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject()
                 .field("script")
                 .startObject()
@@ -142,34 +140,33 @@ public void testSourceParsing() throws Exception {
                 .endObject()
                 .endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
         }
 
         // complex script with embedded template
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
-            Strings.toString(
-                builder.startObject()
-                    .field("script")
-                    .startObject()
-                    .field("lang", "lang")
-                    .startObject("source")
-                    .field("query", "code")
-                    .endObject()
-                    .startObject("options")
-                    .endObject()
-                    .endObject()
-                    .endObject()
-            );
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
+            builder.startObject()
+                .field("script")
+                .startObject()
+                .field("lang", "lang")
+                .startObject("source")
+                .field("query", "code")
+                .endObject()
+                .startObject("options")
+                .endObject()
+                .endObject()
+                .endObject()
+                .toString();
             String code;
 
-            try (XContentBuilder cb = XContentFactory.contentBuilder(builder.contentType())) {
-                code = Strings.toString(cb.startObject().field("query", "code").endObject());
+            try (XContentBuilder cb = MediaTypeRegistry.contentBuilder(builder.contentType())) {
+                code = cb.startObject().field("query", "code").endObject().toString();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource(
                 "lang",
                 code,
@@ -182,29 +179,29 @@ public void testSourceParsing() throws Exception {
 
     public void testSourceParsingErrors() throws Exception {
         // check for missing lang parameter when parsing a script
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("script").startObject().field("source", "code").endObject().endObject();
 
             IllegalArgumentException iae = expectThrows(
                 IllegalArgumentException.class,
-                () -> StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON)
+                () -> StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON)
             );
             assertThat(iae.getMessage(), equalTo("must specify lang for stored script"));
         }
 
         // check for missing source parameter when parsing a script
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("script").startObject().field("lang", "lang").endObject().endObject();
 
             IllegalArgumentException iae = expectThrows(
                 IllegalArgumentException.class,
-                () -> StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON)
+                () -> StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON)
             );
             assertThat(iae.getMessage(), equalTo("must specify source for stored script"));
         }
 
         // check for illegal options parameter when parsing a script
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject()
                 .field("script")
                 .startObject()
@@ -218,17 +215,17 @@ public void testSourceParsingErrors() throws Exception {
 
             IllegalArgumentException iae = expectThrows(
                 IllegalArgumentException.class,
-                () -> StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON)
+                () -> StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON)
             );
             assertThat(iae.getMessage(), equalTo("illegal compiler options [{option=option}] specified"));
         }
 
         // check for unsupported template context
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("template", "code").endObject();
             ParsingException pEx = expectThrows(
                 ParsingException.class,
-                () -> StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON)
+                () -> StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON)
             );
             assertThat(
                 pEx.getMessage(),
@@ -238,20 +235,20 @@ public void testSourceParsingErrors() throws Exception {
     }
 
     public void testEmptyTemplateDeprecations() throws IOException {
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, "", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
             assertWarnings("empty templates should no longer be used");
         }
 
-        try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON)) {
             builder.startObject().field("script").startObject().field("lang", "mustache").field("source", "").endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), XContentType.JSON);
+            StoredScriptSource parsed = StoredScriptSource.parse(BytesReference.bytes(builder), MediaTypeRegistry.JSON);
             StoredScriptSource source = new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, "", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
diff --git a/server/src/test/java/org/opensearch/search/AbstractSearchTestCase.java b/server/src/test/java/org/opensearch/search/AbstractSearchTestCase.java
index 4a5d11ae0c896..c8f1a2491631d 100644
--- a/server/src/test/java/org/opensearch/search/AbstractSearchTestCase.java
+++ b/server/src/test/java/org/opensearch/search/AbstractSearchTestCase.java
@@ -34,14 +34,14 @@
 
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
diff --git a/server/src/test/java/org/opensearch/search/ClearScrollResponseTests.java b/server/src/test/java/org/opensearch/search/ClearScrollResponseTests.java
index e9f1bb09380df..f911d6780d958 100644
--- a/server/src/test/java/org/opensearch/search/ClearScrollResponseTests.java
+++ b/server/src/test/java/org/opensearch/search/ClearScrollResponseTests.java
@@ -33,13 +33,14 @@
 package org.opensearch.search;
 
 import org.opensearch.action.search.ClearScrollResponse;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -58,17 +59,17 @@ public void testToXContent() throws IOException {
     }
 
     public void testToAndFromXContent() throws IOException {
-        XContentType xContentType = randomFrom(XContentType.values());
+        MediaType mediaType = randomFrom(XContentType.values());
         ClearScrollResponse originalResponse = createTestItem();
-        BytesReference originalBytes = toShuffledXContent(originalResponse, xContentType, ToXContent.EMPTY_PARAMS, randomBoolean());
+        BytesReference originalBytes = toShuffledXContent(originalResponse, mediaType, ToXContent.EMPTY_PARAMS, randomBoolean());
         ClearScrollResponse parsedResponse;
-        try (XContentParser parser = createParser(xContentType.xContent(), originalBytes)) {
+        try (XContentParser parser = createParser(mediaType.xContent(), originalBytes)) {
             parsedResponse = ClearScrollResponse.fromXContent(parser);
         }
         assertEquals(originalResponse.isSucceeded(), parsedResponse.isSucceeded());
         assertEquals(originalResponse.getNumFreed(), parsedResponse.getNumFreed());
-        BytesReference parsedBytes = XContentHelper.toXContent(parsedResponse, xContentType, randomBoolean());
-        assertToXContentEquivalent(originalBytes, parsedBytes, xContentType);
+        BytesReference parsedBytes = XContentHelper.toXContent(parsedResponse, mediaType, randomBoolean());
+        assertToXContentEquivalent(originalBytes, parsedBytes, mediaType);
     }
 
     private static ClearScrollResponse createTestItem() {
diff --git a/server/src/test/java/org/opensearch/search/CreatePitSingleNodeTests.java b/server/src/test/java/org/opensearch/search/CreatePitSingleNodeTests.java
new file mode 100644
index 0000000000000..18b35341e0de1
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/CreatePitSingleNodeTests.java
@@ -0,0 +1,620 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search;
+
+import org.opensearch.action.search.CreatePitAction;
+import org.opensearch.action.search.CreatePitController;
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.action.search.DeletePitAction;
+import org.opensearch.action.search.DeletePitInfo;
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.PitTestsUtil;
+import org.opensearch.action.search.SearchPhaseExecutionException;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.Priority;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.index.IndexNotFoundException;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.indices.IndicesService;
+import org.opensearch.search.builder.PointInTimeBuilder;
+import org.opensearch.search.sort.SortOrder;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+import org.hamcrest.Matchers;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+
+import static org.opensearch.action.search.PitTestsUtil.assertSegments;
+import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
+import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.index.query.QueryBuilders.queryStringQuery;
+import static org.opensearch.index.query.QueryBuilders.termQuery;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.Matchers.blankOrNullString;
+import static org.hamcrest.Matchers.not;
+
+/**
+ * Single node integration tests for various PIT use cases such as create pit, search etc
+ */
+public class CreatePitSingleNodeTests extends OpenSearchSingleNodeTestCase {
+    @Override
+    protected boolean resetNodeAfterTest() {
+        return true;
+    }
+
+    @Override
+    protected Settings nodeSettings() {
+        // very frequent checks
+        return Settings.builder()
+            .put(super.nodeSettings())
+            .put(SearchService.KEEPALIVE_INTERVAL_SETTING.getKey(), TimeValue.timeValueMillis(1))
+            .put(CreatePitController.PIT_INIT_KEEP_ALIVE.getKey(), TimeValue.timeValueSeconds(1))
+            .build();
+    }
+
+    public void testCreatePITSuccess() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, client(), pitResponse.getId());
+        client().prepareIndex("index").setId("2").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        SearchResponse searchResponse = client().prepareSearch("index")
+            .setSize(2)
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+            .get();
+        assertHitCount(searchResponse, 1);
+
+        SearchService service = getInstanceFromNode(SearchService.class);
+        assertEquals(2, service.getActiveContexts());
+        validatePitStats("index", 1, 0, 0);
+        validatePitStats("index", 1, 0, 1);
+        service.doClose(); // this kills the keep-alive reaper we have to reset the node after this test
+        assertSegments(true, client());
+        validatePitStats("index", 0, 1, 0);
+        validatePitStats("index", 0, 1, 1);
+    }
+
+    public void testCreatePITWithMultipleIndicesSuccess() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        createIndex("index1", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index1").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index", "index1" });
+        SearchService service = getInstanceFromNode(SearchService.class);
+
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse response = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), response.getId(), response.getCreationTime());
+        assertSegments(false, client(), response.getId());
+        assertEquals(4, response.getSuccessfulShards());
+        assertEquals(4, service.getActiveContexts());
+
+        validatePitStats("index", 1, 0, 0);
+        validatePitStats("index1", 1, 0, 0);
+        service.doClose();
+        assertSegments(true, client());
+        validatePitStats("index", 0, 1, 0);
+        validatePitStats("index1", 0, 1, 0);
+    }
+
+    public void testCreatePITWithShardReplicasSuccess() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 1).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, client(), pitResponse.getId());
+        client().prepareIndex("index").setId("2").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        SearchResponse searchResponse = client().prepareSearch("index")
+            .setSize(2)
+            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+            .get();
+        assertHitCount(searchResponse, 1);
+
+        SearchService service = getInstanceFromNode(SearchService.class);
+        assertEquals(2, service.getActiveContexts());
+        validatePitStats("index", 1, 0, 0);
+        validatePitStats("index", 1, 0, 1);
+        service.doClose();
+        assertSegments(true, client());
+        validatePitStats("index", 0, 1, 0);
+        validatePitStats("index", 0, 1, 1);
+    }
+
+    public void testCreatePITWithNonExistentIndex() {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index", "index1" });
+        SearchService service = getInstanceFromNode(SearchService.class);
+
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+
+        ExecutionException ex = expectThrows(ExecutionException.class, execute::get);
+
+        assertTrue(ex.getMessage().contains("no such index [index1]"));
+        assertEquals(0, service.getActiveContexts());
+        assertSegments(true, client());
+        service.doClose();
+    }
+
+    public void testCreatePITOnCloseIndex() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("index").setId("2").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+        client().admin().indices().prepareClose("index").get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+
+        ExecutionException ex = expectThrows(ExecutionException.class, execute::get);
+
+        assertTrue(ex.getMessage().contains("IndexClosedException"));
+
+        SearchService service = getInstanceFromNode(SearchService.class);
+        assertEquals(0, service.getActiveContexts());
+        PitTestsUtil.assertGetAllPitsEmpty(client());
+        assertSegments(true, client());
+        service.doClose();
+    }
+
+    public void testPitSearchOnDeletedIndex() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        client().admin().indices().prepareDelete("index").get();
+
+        IndexNotFoundException ex = expectThrows(IndexNotFoundException.class, () -> {
+            client().prepareSearch()
+                .setSize(2)
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                .get();
+        });
+        assertTrue(ex.getMessage().contains("no such index [index]"));
+        SearchService service = getInstanceFromNode(SearchService.class);
+        PitTestsUtil.assertGetAllPitsEmpty(client());
+        assertEquals(0, service.getActiveContexts());
+        assertSegments(true, client());
+        service.doClose();
+    }
+
+    public void testInvalidPitId() {
+        createIndex("idx");
+        String id = "c2Nhbjs2OzM0NDg1ODpzRlBLc0FXNlNyNm5JWUc1";
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> client().prepareSearch()
+                .setSize(2)
+                .setPointInTime(new PointInTimeBuilder(id).setKeepAlive(TimeValue.timeValueDays(1)))
+                .get()
+        );
+        assertEquals("invalid id: [" + id + "]", e.getMessage());
+    }
+
+    public void testPitSearchOnCloseIndex() throws ExecutionException, InterruptedException {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, client(), pitResponse.getId());
+        SearchService service = getInstanceFromNode(SearchService.class);
+        assertEquals(2, service.getActiveContexts());
+        validatePitStats("index", 1, 0, 0);
+        validatePitStats("index", 1, 0, 1);
+
+        client().admin().indices().prepareClose("index").get();
+        SearchPhaseExecutionException ex = expectThrows(SearchPhaseExecutionException.class, () -> {
+            SearchResponse searchResponse = client().prepareSearch()
+                .setSize(2)
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                .get();
+        });
+        assertTrue(ex.shardFailures()[0].reason().contains("SearchContextMissingException"));
+        assertEquals(0, service.getActiveContexts());
+        PitTestsUtil.assertGetAllPitsEmpty(client());
+        assertSegments(true, client());
+        // PIT reader contexts are lost after close, verifying it with open index api
+        client().admin().indices().prepareOpen("index").get();
+        ex = expectThrows(SearchPhaseExecutionException.class, () -> {
+            client().prepareSearch()
+                .setSize(2)
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                .get();
+        });
+        assertTrue(ex.shardFailures()[0].reason().contains("SearchContextMissingException"));
+        assertEquals(0, service.getActiveContexts());
+        service.doClose();
+    }
+
+    public void testMaxOpenPitContexts() throws Exception {
+        createIndex("index");
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        SearchService service = getInstanceFromNode(SearchService.class);
+
+        for (int i = 0; i < SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY); i++) {
+            client().execute(CreatePitAction.INSTANCE, request).get();
+        }
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        ExecutionException ex = expectThrows(ExecutionException.class, execute::get);
+
+        assertTrue(
+            ex.getMessage()
+                .contains(
+                    "Trying to create too many Point In Time contexts. "
+                        + "Must be less than or equal to: ["
+                        + SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY)
+                        + "]. "
+                        + "This limit can be set by changing the [search.max_open_pit_context] setting."
+                )
+        );
+        final int maxPitContexts = SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY);
+        validatePitStats("index", maxPitContexts, 0, 0);
+        service.doClose();
+        validatePitStats("index", 0, maxPitContexts, 0);
+    }
+
+    public void testCreatePitMoreThanMaxOpenPitContexts() throws Exception {
+        createIndex("index");
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        SearchService service = getInstanceFromNode(SearchService.class);
+        List<String> pitIds = new ArrayList<>();
+
+        try {
+            for (int i = 0; i < 1000; i++) {
+                CreatePitResponse cpr = client().execute(CreatePitAction.INSTANCE, request).actionGet();
+                if (cpr.getId() != null) pitIds.add(cpr.getId());
+            }
+        } catch (Exception ex) {
+            assertTrue(
+                ((SearchPhaseExecutionException) ex).getDetailedMessage()
+                    .contains(
+                        "Trying to create too many Point In Time contexts. "
+                            + "Must be less than or equal to: ["
+                            + SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY)
+                            + "]. "
+                            + "This limit can be set by changing the [search.max_open_pit_context] setting."
+                    )
+            );
+        }
+        final int maxPitContexts = SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY);
+        validatePitStats("index", maxPitContexts, 0, 0);
+        // deleteall
+        DeletePitRequest deletePITRequest = new DeletePitRequest(pitIds.toArray(new String[pitIds.size()]));
+
+        /**
+         * When we invoke delete again, returns success after clearing the remaining readers. Asserting reader context
+         * not found exceptions don't result in failures ( as deletion in one node is successful )
+         */
+        ActionFuture<DeletePitResponse> execute = client().execute(DeletePitAction.INSTANCE, deletePITRequest);
+        DeletePitResponse deletePITResponse = execute.get();
+        for (DeletePitInfo deletePitInfo : deletePITResponse.getDeletePitResults()) {
+            assertThat(deletePitInfo.getPitId(), not(blankOrNullString()));
+            assertTrue(deletePitInfo.isSuccessful());
+        }
+        validatePitStats("index", 0, maxPitContexts, 0);
+        client().execute(CreatePitAction.INSTANCE, request).get();
+        validatePitStats("index", 1, maxPitContexts, 0);
+        service.doClose();
+        validatePitStats("index", 0, maxPitContexts + 1, 0);
+    }
+
+    public void testOpenPitContextsConcurrently() throws Exception {
+        createIndex("index");
+        final int maxPitContexts = SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY);
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        SearchService service = getInstanceFromNode(SearchService.class);
+        Thread[] threads = new Thread[randomIntBetween(2, 8)];
+        CountDownLatch latch = new CountDownLatch(threads.length);
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new Thread(() -> {
+                latch.countDown();
+                try {
+                    latch.await();
+                    for (;;) {
+                        try {
+                            client().execute(CreatePitAction.INSTANCE, request).get();
+                        } catch (ExecutionException e) {
+                            assertTrue(
+                                e.getMessage()
+                                    .contains(
+                                        "Trying to create too many Point In Time contexts. "
+                                            + "Must be less than or equal to: ["
+                                            + SearchService.MAX_OPEN_PIT_CONTEXT.get(Settings.EMPTY)
+                                            + "]. "
+                                            + "This limit can be set by changing the ["
+                                            + SearchService.MAX_OPEN_PIT_CONTEXT.getKey()
+                                            + "] setting."
+                                    )
+                            );
+                            return;
+                        }
+                    }
+                } catch (Exception e) {
+                    throw new AssertionError(e);
+                }
+            });
+            threads[i].setName("opensearch[node_s_0][search]");
+            threads[i].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+        assertThat(service.getActiveContexts(), equalTo(maxPitContexts));
+        validatePitStats("index", maxPitContexts, 0, 0);
+        service.doClose();
+        validatePitStats("index", 0, maxPitContexts, 0);
+    }
+
+    /**
+     * Point in time search should return the same results as creation time and index updates should not affect the PIT search results
+     */
+    public void testPitAfterUpdateIndex() throws Exception {
+        client().admin().indices().prepareCreate("test").setSettings(Settings.builder().put("index.number_of_shards", 5)).get();
+        client().admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).setWaitForGreenStatus().get();
+
+        for (int i = 0; i < 50; i++) {
+            client().prepareIndex("test")
+                .setId(Integer.toString(i))
+                .setSource(
+                    jsonBuilder().startObject()
+                        .field("user", "foobar")
+                        .field("postDate", System.currentTimeMillis())
+                        .field("message", "test")
+                        .endObject()
+                )
+                .get();
+        }
+        client().admin().indices().prepareRefresh().get();
+
+        // create pit
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueMinutes(2), true);
+        request.setIndices(new String[] { "test" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        SearchService service = getInstanceFromNode(SearchService.class);
+
+        assertThat(
+            client().prepareSearch()
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(0)
+                .setQuery(matchAllQuery())
+                .get()
+                .getHits()
+                .getTotalHits().value,
+            Matchers.equalTo(50L)
+        );
+
+        assertThat(
+            client().prepareSearch()
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(0)
+                .setQuery(termQuery("message", "test"))
+                .get()
+                .getHits()
+                .getTotalHits().value,
+            Matchers.equalTo(50L)
+        );
+        assertThat(
+            client().prepareSearch()
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(0)
+                .setQuery(termQuery("message", "test"))
+                .get()
+                .getHits()
+                .getTotalHits().value,
+            Matchers.equalTo(50L)
+        );
+        assertThat(
+            client().prepareSearch()
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(0)
+                .setQuery(termQuery("message", "update"))
+                .get()
+                .getHits()
+                .getTotalHits().value,
+            Matchers.equalTo(0L)
+        );
+        assertThat(
+            client().prepareSearch()
+                .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                .setSize(0)
+                .setQuery(termQuery("message", "update"))
+                .get()
+                .getHits()
+                .getTotalHits().value,
+            Matchers.equalTo(0L)
+        );
+
+        // update index
+        SearchResponse searchResponse = client().prepareSearch()
+            .setQuery(queryStringQuery("user:foobar"))
+            .setSize(50)
+            .addSort("postDate", SortOrder.ASC)
+            .get();
+        try {
+            do {
+                for (SearchHit searchHit : searchResponse.getHits().getHits()) {
+                    Map<String, Object> map = searchHit.getSourceAsMap();
+                    map.put("message", "update");
+                    client().prepareIndex("test").setId(searchHit.getId()).setSource(map).get();
+                }
+                searchResponse = client().prepareSearch().setSize(0).setQuery(termQuery("message", "test")).get();
+
+            } while (searchResponse.getHits().getHits().length > 0);
+
+            client().admin().indices().prepareRefresh().get();
+            assertThat(
+                client().prepareSearch().setSize(0).setQuery(matchAllQuery()).get().getHits().getTotalHits().value,
+                Matchers.equalTo(50L)
+            );
+            /**
+             * assert without point in time
+             */
+
+            assertThat(
+                client().prepareSearch().setSize(0).setQuery(termQuery("message", "test")).get().getHits().getTotalHits().value,
+                Matchers.equalTo(0L)
+            );
+            assertThat(
+                client().prepareSearch().setSize(0).setQuery(termQuery("message", "test")).get().getHits().getTotalHits().value,
+                Matchers.equalTo(0L)
+            );
+            assertThat(
+                client().prepareSearch().setSize(0).setQuery(termQuery("message", "update")).get().getHits().getTotalHits().value,
+                Matchers.equalTo(50L)
+            );
+            assertThat(
+                client().prepareSearch().setSize(0).setQuery(termQuery("message", "update")).get().getHits().getTotalHits().value,
+                Matchers.equalTo(50L)
+            );
+            /**
+             * using point in time id will have the same search results as ones before update
+             */
+            assertThat(
+                client().prepareSearch()
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                    .setSize(0)
+                    .setQuery(termQuery("message", "test"))
+                    .get()
+                    .getHits()
+                    .getTotalHits().value,
+                Matchers.equalTo(50L)
+            );
+            assertThat(
+                client().prepareSearch()
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                    .setSize(0)
+                    .setQuery(termQuery("message", "test"))
+                    .get()
+                    .getHits()
+                    .getTotalHits().value,
+                Matchers.equalTo(50L)
+            );
+            assertThat(
+                client().prepareSearch()
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                    .setSize(0)
+                    .setQuery(termQuery("message", "update"))
+                    .get()
+                    .getHits()
+                    .getTotalHits().value,
+                Matchers.equalTo(0L)
+            );
+            assertThat(
+                client().prepareSearch()
+                    .setPointInTime(new PointInTimeBuilder(pitResponse.getId()))
+                    .setSize(0)
+                    .setQuery(termQuery("message", "update"))
+                    .get()
+                    .getHits()
+                    .getTotalHits().value,
+                Matchers.equalTo(0L)
+            );
+            validatePitStats("test", 1, 0, 0);
+        } finally {
+            service.doClose();
+            assertEquals(0, service.getActiveContexts());
+            validatePitStats("test", 0, 1, 0);
+            PitTestsUtil.assertGetAllPitsEmpty(client());
+            assertSegments(true, client());
+        }
+    }
+
+    public void testConcurrentSearches() throws Exception {
+        createIndex("index", Settings.builder().put("index.number_of_shards", 2).put("index.number_of_replicas", 0).build());
+        client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
+
+        CreatePitRequest request = new CreatePitRequest(TimeValue.timeValueDays(1), true);
+        request.setIndices(new String[] { "index" });
+        ActionFuture<CreatePitResponse> execute = client().execute(CreatePitAction.INSTANCE, request);
+        CreatePitResponse pitResponse = execute.get();
+        PitTestsUtil.assertUsingGetAllPits(client(), pitResponse.getId(), pitResponse.getCreationTime());
+        assertSegments(false, client(), pitResponse.getId());
+        Thread[] threads = new Thread[5];
+        CountDownLatch latch = new CountDownLatch(threads.length);
+
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new Thread(() -> {
+                latch.countDown();
+                try {
+                    latch.await();
+                    for (int j = 0; j < 50; j++) {
+                        client().prepareSearch()
+                            .setSize(2)
+                            .setPointInTime(new PointInTimeBuilder(pitResponse.getId()).setKeepAlive(TimeValue.timeValueDays(1)))
+                            .execute()
+                            .get();
+                    }
+                } catch (Exception e) {
+                    throw new AssertionError(e);
+                }
+            });
+            threads[i].setName("opensearch[node_s_0][search]");
+            threads[i].start();
+        }
+        for (Thread thread : threads) {
+            thread.join();
+        }
+
+        SearchService service = getInstanceFromNode(SearchService.class);
+        assertEquals(2, service.getActiveContexts());
+        validatePitStats("index", 1, 0, 0);
+        validatePitStats("index", 1, 0, 1);
+        service.doClose();
+        assertEquals(0, service.getActiveContexts());
+        validatePitStats("index", 0, 1, 0);
+        validatePitStats("index", 0, 1, 1);
+        PitTestsUtil.assertGetAllPitsEmpty(client());
+    }
+
+    public void validatePitStats(String index, long expectedPitCurrent, long expectedPitCount, int shardId) throws ExecutionException,
+        InterruptedException {
+        IndicesService indicesService = getInstanceFromNode(IndicesService.class);
+        IndexService indexService = indicesService.indexServiceSafe(resolveIndex(index));
+        IndexShard indexShard = indexService.getShard(shardId);
+        assertEquals(expectedPitCurrent, indexShard.searchStats().getTotal().getPitCurrent());
+        assertEquals(expectedPitCount, indexShard.searchStats().getTotal().getPitCount());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/DefaultSearchContextTests.java b/server/src/test/java/org/opensearch/search/DefaultSearchContextTests.java
index e1cf74bdd6aeb..347011af98c6d 100644
--- a/server/src/test/java/org/opensearch/search/DefaultSearchContextTests.java
+++ b/server/src/test/java/org/opensearch/search/DefaultSearchContextTests.java
@@ -32,24 +32,34 @@
 
 package org.opensearch.search;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.Version;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.cache.IndexCache;
@@ -61,36 +71,60 @@
 import org.opensearch.index.query.ParsedQuery;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.internal.AliasFilter;
 import org.opensearch.search.internal.LegacyReaderContext;
+import org.opensearch.search.internal.PitReaderContext;
 import org.opensearch.search.internal.ReaderContext;
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.slice.SliceBuilder;
 import org.opensearch.search.sort.SortAndFormats;
+import org.opensearch.test.FeatureFlagSetter;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.UUID;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.anyBoolean;
+import static org.mockito.Mockito.anyString;
 import static org.mockito.Mockito.eq;
-import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.nullable;
 import static org.mockito.Mockito.when;
 
 public class DefaultSearchContextTests extends OpenSearchTestCase {
+    private final ExecutorService executor;
+
+    @ParametersFactory
+    public static Collection<Object[]> concurrency() {
+        return Arrays.asList(new Integer[] { 0 }, new Integer[] { 5 });
+    }
+
+    public DefaultSearchContextTests(int concurrency) {
+        this.executor = (concurrency > 0) ? Executors.newFixedThreadPool(concurrency) : null;
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+
+        if (executor != null) {
+            ThreadPool.terminate(executor, 10, TimeUnit.SECONDS);
+        }
+    }
 
     public void testPreProcess() throws Exception {
         TimeValue timeout = new TimeValue(randomIntBetween(1, 100));
@@ -108,10 +142,12 @@ public void testPreProcess() throws Exception {
         int maxResultWindow = randomIntBetween(50, 100);
         int maxRescoreWindow = randomIntBetween(50, 100);
         int maxSlicesPerScroll = randomIntBetween(50, 100);
+        int maxSlicesPerPit = randomIntBetween(50, 100);
         Settings settings = Settings.builder()
             .put("index.max_result_window", maxResultWindow)
             .put("index.max_slices_per_scroll", maxSlicesPerScroll)
             .put("index.max_rescore_window", maxRescoreWindow)
+            .put("index.max_slices_per_pit", maxSlicesPerPit)
             .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
             .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
             .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
@@ -183,6 +219,7 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
             contextWithoutScroll.from(300);
@@ -225,6 +262,7 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
             context1.from(300);
@@ -274,13 +312,13 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
             );
 
             readerContext.close();
-            readerContext = new ReaderContext(
+            readerContext = new LegacyReaderContext(
                 newContextId(),
                 indexService,
                 indexShard,
                 searcherSupplier.get(),
-                randomNonNegativeLong(),
-                false
+                shardSearchRequest,
+                randomNonNegativeLong()
             );
             // rescore is null but sliceBuilder is not null
             DefaultSearchContext context2 = new DefaultSearchContext(
@@ -295,6 +333,7 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
 
@@ -334,11 +373,16 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
             ParsedQuery parsedQuery = ParsedQuery.parsedMatchAllQuery();
             context3.sliceBuilder(null).parsedQuery(parsedQuery).preProcess(false);
             assertEquals(context3.query(), context3.buildFilteredQuery(parsedQuery.query()));
+            // make sure getPreciseRelativeTimeInMillis is same as System.nanoTime()
+            long timeToleranceInMs = 10;
+            long currTime = TimeValue.nsecToMSec(System.nanoTime());
+            assertTrue(Math.abs(context3.getRelativeTimeInMillis(false) - currTime) <= timeToleranceInMs);
 
             when(queryShardContext.getIndexSettings()).thenReturn(indexSettings);
             when(queryShardContext.fieldMapper(anyString())).thenReturn(mock(MappedFieldType.class));
@@ -365,6 +409,7 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
             context4.sliceBuilder(new SliceBuilder(1, 2)).parsedQuery(parsedQuery).preProcess(false);
@@ -374,6 +419,53 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
             assertTrue(query1 instanceof MatchNoDocsQuery || query2 instanceof MatchNoDocsQuery);
 
             readerContext.close();
+
+            ReaderContext pitReaderContext = new PitReaderContext(
+                newContextId(),
+                indexService,
+                indexShard,
+                searcherSupplier.get(),
+                1000,
+                true
+            );
+            DefaultSearchContext context5 = new DefaultSearchContext(
+                pitReaderContext,
+                shardSearchRequest,
+                target,
+                null,
+                bigArrays,
+                null,
+                timeout,
+                null,
+                false,
+                Version.CURRENT,
+                false,
+                executor,
+                null
+            );
+            int numSlicesForPit = maxSlicesPerPit + randomIntBetween(1, 100);
+            when(sliceBuilder.getMax()).thenReturn(numSlicesForPit);
+            context5.sliceBuilder(sliceBuilder);
+
+            OpenSearchRejectedExecutionException exception1 = expectThrows(
+                OpenSearchRejectedExecutionException.class,
+                () -> context5.preProcess(false)
+            );
+            assertThat(
+                exception1.getMessage(),
+                equalTo(
+                    "The number of slices ["
+                        + numSlicesForPit
+                        + "] is too large. It must "
+                        + "be less than ["
+                        + maxSlicesPerPit
+                        + "]. This limit can be set by changing the ["
+                        + IndexSettings.MAX_SLICES_PER_PIT.getKey()
+                        + "] index level setting."
+                )
+            );
+            pitReaderContext.close();
+
             threadPool.shutdown();
         }
     }
@@ -446,6 +538,7 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
                 false,
                 Version.CURRENT,
                 false,
+                executor,
                 null
             );
             assertThat(context.searcher().hasCancellations(), is(false));
@@ -460,6 +553,159 @@ protected Engine.Searcher acquireSearcherInternal(String source) {
         }
     }
 
+    public void testSearchPathEvaluationUsingSortField() throws Exception {
+        // enable the concurrent set FeatureFlag
+        FeatureFlagSetter.set(FeatureFlags.CONCURRENT_SEGMENT_SEARCH);
+        ShardSearchRequest shardSearchRequest = mock(ShardSearchRequest.class);
+        when(shardSearchRequest.searchType()).thenReturn(SearchType.DEFAULT);
+        ShardId shardId = new ShardId("index", UUID.randomUUID().toString(), 1);
+        when(shardSearchRequest.shardId()).thenReturn(shardId);
+
+        ThreadPool threadPool = new TestThreadPool(this.getClass().getName());
+        IndexShard indexShard = mock(IndexShard.class);
+        QueryCachingPolicy queryCachingPolicy = mock(QueryCachingPolicy.class);
+        when(indexShard.getQueryCachingPolicy()).thenReturn(queryCachingPolicy);
+        when(indexShard.getThreadPool()).thenReturn(threadPool);
+
+        Settings settings = Settings.builder()
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 2)
+            .build();
+
+        IndexService indexService = mock(IndexService.class);
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        when(indexService.newQueryShardContext(eq(shardId.id()), any(), any(), nullable(String.class), anyBoolean())).thenReturn(
+            queryShardContext
+        );
+
+        IndexMetadata indexMetadata = IndexMetadata.builder("index").settings(settings).build();
+        IndexSettings indexSettings = new IndexSettings(indexMetadata, Settings.EMPTY);
+        when(indexService.getIndexSettings()).thenReturn(indexSettings);
+
+        BigArrays bigArrays = new MockBigArrays(new MockPageCacheRecycler(Settings.EMPTY), new NoneCircuitBreakerService());
+
+        try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir)) {
+
+            final Supplier<Engine.SearcherSupplier> searcherSupplier = () -> new Engine.SearcherSupplier(Function.identity()) {
+                @Override
+                protected void doClose() {}
+
+                @Override
+                protected Engine.Searcher acquireSearcherInternal(String source) {
+                    try {
+                        IndexReader reader = w.getReader();
+                        return new Engine.Searcher(
+                            "test",
+                            reader,
+                            IndexSearcher.getDefaultSimilarity(),
+                            IndexSearcher.getDefaultQueryCache(),
+                            IndexSearcher.getDefaultQueryCachingPolicy(),
+                            reader
+                        );
+                    } catch (IOException exc) {
+                        throw new AssertionError(exc);
+                    }
+                }
+            };
+
+            SearchShardTarget target = new SearchShardTarget("node", shardId, null, OriginalIndices.NONE);
+            ReaderContext readerContext = new ReaderContext(
+                newContextId(),
+                indexService,
+                indexShard,
+                searcherSupplier.get(),
+                randomNonNegativeLong(),
+                false
+            );
+
+            final ClusterService clusterService = mock(ClusterService.class);
+            final ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+            clusterSettings.registerSetting(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING);
+            clusterSettings.applySettings(
+                Settings.builder().put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build()
+            );
+            when(clusterService.getClusterSettings()).thenReturn(clusterSettings);
+            DefaultSearchContext context = new DefaultSearchContext(
+                readerContext,
+                shardSearchRequest,
+                target,
+                null,
+                bigArrays,
+                null,
+                null,
+                null,
+                false,
+                Version.CURRENT,
+                false,
+                executor,
+                null
+            );
+
+            // Case1: if sort is on timestamp field, non-concurrent path is used
+            context.sort(
+                new SortAndFormats(new Sort(new SortField("@timestamp", SortField.Type.INT)), new DocValueFormat[] { DocValueFormat.RAW })
+            );
+            context.evaluateRequestShouldUseConcurrentSearch();
+            assertFalse(context.shouldUseConcurrentSearch());
+            assertThrows(SetOnce.AlreadySetException.class, context::evaluateRequestShouldUseConcurrentSearch);
+
+            // Case2: if sort is on other field, concurrent path is used
+            context = new DefaultSearchContext(
+                readerContext,
+                shardSearchRequest,
+                target,
+                clusterService,
+                bigArrays,
+                null,
+                null,
+                null,
+                false,
+                Version.CURRENT,
+                false,
+                executor,
+                null
+            );
+            context.sort(
+                new SortAndFormats(new Sort(new SortField("test2", SortField.Type.INT)), new DocValueFormat[] { DocValueFormat.RAW })
+            );
+            context.evaluateRequestShouldUseConcurrentSearch();
+            if (executor == null) {
+                assertFalse(context.shouldUseConcurrentSearch());
+            } else {
+                assertTrue(context.shouldUseConcurrentSearch());
+            }
+            assertThrows(SetOnce.AlreadySetException.class, context::evaluateRequestShouldUseConcurrentSearch);
+
+            // Case 3: With no sort, concurrent path is used
+            context = new DefaultSearchContext(
+                readerContext,
+                shardSearchRequest,
+                target,
+                clusterService,
+                bigArrays,
+                null,
+                null,
+                null,
+                false,
+                Version.CURRENT,
+                false,
+                executor,
+                null
+            );
+            context.evaluateRequestShouldUseConcurrentSearch();
+            if (executor == null) {
+                assertFalse(context.shouldUseConcurrentSearch());
+            } else {
+                assertTrue(context.shouldUseConcurrentSearch());
+            }
+            assertThrows(SetOnce.AlreadySetException.class, context::evaluateRequestShouldUseConcurrentSearch);
+
+            // shutdown the threadpool
+            threadPool.shutdown();
+        }
+    }
+
     private ShardSearchContextId newContextId() {
         return new ShardSearchContextId(UUIDs.randomBase64UUID(), randomNonNegativeLong());
     }
diff --git a/server/src/test/java/org/opensearch/search/DeletePitResponseTests.java b/server/src/test/java/org/opensearch/search/DeletePitResponseTests.java
new file mode 100644
index 0000000000000..8a9f635f7ef3b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/DeletePitResponseTests.java
@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search;
+
+import org.opensearch.action.search.DeletePitInfo;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
+
+public class DeletePitResponseTests extends OpenSearchTestCase {
+
+    public void testDeletePitResponseToXContent() throws IOException {
+        DeletePitInfo deletePitInfo = new DeletePitInfo(true, "pitId");
+        List<DeletePitInfo> deletePitInfoList = new ArrayList<>();
+        deletePitInfoList.add(deletePitInfo);
+        DeletePitResponse deletePitResponse = new DeletePitResponse(deletePitInfoList);
+
+        try (XContentBuilder builder = JsonXContent.contentBuilder()) {
+            deletePitResponse.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        }
+        assertEquals(true, deletePitResponse.getDeletePitResults().get(0).getPitId().equals("pitId"));
+        assertEquals(true, deletePitResponse.getDeletePitResults().get(0).isSuccessful());
+    }
+
+    public void testDeletePitResponseToAndFromXContent() throws IOException {
+        XContentType xContentType = randomFrom(XContentType.values());
+        DeletePitResponse originalResponse = createDeletePitResponseTestItem();
+
+        BytesReference originalBytes = toShuffledXContent(originalResponse, xContentType, ToXContent.EMPTY_PARAMS, randomBoolean());
+        DeletePitResponse parsedResponse;
+        try (XContentParser parser = createParser(xContentType.xContent(), originalBytes)) {
+            parsedResponse = DeletePitResponse.fromXContent(parser);
+        }
+        assertEquals(
+            originalResponse.getDeletePitResults().get(0).isSuccessful(),
+            parsedResponse.getDeletePitResults().get(0).isSuccessful()
+        );
+        assertEquals(originalResponse.getDeletePitResults().get(0).getPitId(), parsedResponse.getDeletePitResults().get(0).getPitId());
+        BytesReference parsedBytes = XContentHelper.toXContent(parsedResponse, xContentType, randomBoolean());
+        assertToXContentEquivalent(originalBytes, parsedBytes, xContentType);
+    }
+
+    private static DeletePitResponse createDeletePitResponseTestItem() {
+        DeletePitInfo deletePitInfo = new DeletePitInfo(randomBoolean(), "pitId");
+        List<DeletePitInfo> deletePitInfoList = new ArrayList<>();
+        deletePitInfoList.add(deletePitInfo);
+        return new DeletePitResponse(deletePitInfoList);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/DocValueFormatTests.java b/server/src/test/java/org/opensearch/search/DocValueFormatTests.java
index 36a6eb3ae87b0..5638eeb59c337 100644
--- a/server/src/test/java/org/opensearch/search/DocValueFormatTests.java
+++ b/server/src/test/java/org/opensearch/search/DocValueFormatTests.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.document.InetAddressPoint;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.time.DateFormatter;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.mapper.DateFieldMapper.Resolution;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -48,7 +48,7 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.longEncode;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.longEncode;
 
 public class DocValueFormatTests extends OpenSearchTestCase {
 
@@ -76,6 +76,7 @@ public void testSerialization() throws Exception {
         DocValueFormat vf = in.readNamedWriteable(DocValueFormat.class);
         assertEquals(DocValueFormat.Decimal.class, vf.getClass());
         assertEquals("###.##", ((DocValueFormat.Decimal) vf).pattern);
+        assertEquals(decimalFormat, vf);
 
         DateFormatter formatter = DateFormatter.forPattern("epoch_second");
         DocValueFormat.DateTime dateFormat = new DocValueFormat.DateTime(formatter, ZoneOffset.ofHours(1), Resolution.MILLISECONDS);
@@ -87,6 +88,7 @@ public void testSerialization() throws Exception {
         assertEquals("epoch_second", ((DocValueFormat.DateTime) vf).formatter.pattern());
         assertEquals(ZoneOffset.ofHours(1), ((DocValueFormat.DateTime) vf).timeZone);
         assertEquals(Resolution.MILLISECONDS, ((DocValueFormat.DateTime) vf).resolution);
+        assertEquals(dateFormat, vf);
 
         DocValueFormat.DateTime nanosDateFormat = new DocValueFormat.DateTime(formatter, ZoneOffset.ofHours(1), Resolution.NANOSECONDS);
         out = new BytesStreamOutput();
@@ -97,6 +99,7 @@ public void testSerialization() throws Exception {
         assertEquals("epoch_second", ((DocValueFormat.DateTime) vf).formatter.pattern());
         assertEquals(ZoneOffset.ofHours(1), ((DocValueFormat.DateTime) vf).timeZone);
         assertEquals(Resolution.NANOSECONDS, ((DocValueFormat.DateTime) vf).resolution);
+        assertEquals(nanosDateFormat, vf);
 
         out = new BytesStreamOutput();
         out.writeNamedWriteable(DocValueFormat.GEOHASH);
@@ -230,4 +233,23 @@ public void testDecimalParse() {
         assertEquals(0.859d, parser.parseDouble("0.859", true, null), 0.0d);
         assertEquals(0.8598023539251286d, parser.parseDouble("0.8598023539251286", true, null), 0.0d);
     }
+
+    public void testLongParse() {
+        assertEquals(DocValueFormat.RAW.format(0), 0L);
+        assertEquals(DocValueFormat.RAW.format(-1), -1L);
+        assertEquals(DocValueFormat.RAW.format(1), 1L);
+        assertEquals(DocValueFormat.RAW.format(0d), 0d);
+        assertEquals(DocValueFormat.RAW.format(9.5d), 9.5d);
+        assertEquals(DocValueFormat.RAW.format(-1d), -1d);
+    }
+
+    public void testGeoTileParse() {
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(0, 0, 0)), "0/0/0");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(30, 70, 15)), "15/19114/7333");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(179.999, 89.999, 29)), "29/536869420/0");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(-179.999, -89.999, 29)), "29/1491/536870911");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(1, 1, 2)), "2/2/1");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(13, 95, 1)), "1/1/0");
+        assertEquals(DocValueFormat.GEOTILE.format(longEncode(13, -95, 1)), "1/1/1");
+    }
 }
diff --git a/server/src/test/java/org/opensearch/search/GenericSearchExtBuilderTests.java b/server/src/test/java/org/opensearch/search/GenericSearchExtBuilderTests.java
new file mode 100644
index 0000000000000..8fb1814962155
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/GenericSearchExtBuilderTests.java
@@ -0,0 +1,422 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.search;
+
+import org.opensearch.Version;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchResponseTests;
+import org.opensearch.action.search.ShardSearchFailure;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.plugins.SearchPlugin;
+import org.opensearch.rest.action.search.RestSearchAction;
+import org.opensearch.search.aggregations.AggregationsTests;
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.internal.InternalSearchResponse;
+import org.opensearch.search.profile.SearchProfileShardResults;
+import org.opensearch.search.profile.SearchProfileShardResultsTests;
+import org.opensearch.search.suggest.Suggest;
+import org.opensearch.search.suggest.SuggestTests;
+import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.UUID;
+
+import static java.util.Collections.singletonMap;
+
+public class GenericSearchExtBuilderTests extends OpenSearchTestCase {
+
+    private static final NamedXContentRegistry xContentRegistry;
+    static {
+        List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(InternalAggregationTestCase.getDefaultNamedXContents());
+        namedXContents.addAll(SuggestTests.getDefaultNamedXContents());
+        namedXContents.add(
+            new NamedXContentRegistry.Entry(
+                SearchExtBuilder.class,
+                GenericSearchExtBuilder.EXT_BUILDER_NAME,
+                GenericSearchExtBuilder::fromXContent
+            )
+        );
+        xContentRegistry = new NamedXContentRegistry(namedXContents);
+    }
+
+    private final NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(
+        new SearchModule(Settings.EMPTY, List.of(new SearchPlugin() {
+            @Override
+            public List<SearchExtSpec<?>> getSearchExts() {
+                return List.of(
+                    new SearchExtSpec<>(
+                        GenericSearchExtBuilder.EXT_BUILDER_NAME,
+                        GenericSearchExtBuilder::new,
+                        GenericSearchExtBuilder::fromXContent
+                    )
+                );
+            }
+        })).getNamedWriteables()
+    );
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        return xContentRegistry;
+    }
+
+    SearchResponseTests srt = new SearchResponseTests();
+    private AggregationsTests aggregationsTests = new AggregationsTests();
+
+    @Before
+    public void init() throws Exception {
+        aggregationsTests.init();
+    }
+
+    @After
+    public void cleanUp() throws Exception {
+        aggregationsTests.cleanUp();
+    }
+
+    public void testFromXContentWithUnregisteredSearchExtBuilders() throws IOException {
+        List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>(InternalAggregationTestCase.getDefaultNamedXContents());
+        namedXContents.addAll(SuggestTests.getDefaultNamedXContents());
+        String dummyId = UUID.randomUUID().toString();
+        List<SearchExtBuilder> extBuilders = List.of(
+            new SimpleValueSearchExtBuilder(dummyId),
+            new MapSearchExtBuilder(Map.of("x", "y", "a", "b")),
+            new ListSearchExtBuilder(List.of("1", "2", "3"))
+        );
+        SearchResponse response = srt.createTestItem(false, extBuilders);
+        MediaType xcontentType = randomFrom(XContentType.values());
+        boolean humanReadable = randomBoolean();
+        final ToXContent.Params params = new ToXContent.MapParams(singletonMap(RestSearchAction.TYPED_KEYS_PARAM, "true"));
+        BytesReference originalBytes = toShuffledXContent(response, xcontentType, params, humanReadable);
+        XContentParser parser = createParser(new NamedXContentRegistry(namedXContents), xcontentType.xContent(), originalBytes);
+        SearchResponse parsed = SearchResponse.fromXContent(parser);
+        assertEquals(extBuilders.size(), response.getInternalResponse().getSearchExtBuilders().size());
+
+        List<SearchExtBuilder> actual = parsed.getInternalResponse().getSearchExtBuilders();
+        assertEquals(extBuilders.size(), actual.size());
+        for (int i = 0; i < actual.size(); i++) {
+            assertTrue(actual.get(0) instanceof GenericSearchExtBuilder);
+        }
+    }
+
+    // This test case fails because GenericSearchExtBuilder does not retain the name of the SearchExtBuilder that it is replacing.
+    // GenericSearchExtBuilder has its own "generic_ext" section name.
+    // public void testFromXContentWithSearchExtBuilders() throws IOException {
+    // String dummyId = UUID.randomUUID().toString();
+    // srt.doFromXContentTestWithRandomFields(createTestItem(false, List.of(new SimpleValueSearchExtBuilder(dummyId))), false);
+    // }
+
+    public void testFromXContentWithGenericSearchExtBuildersForSimpleValues() throws IOException {
+        String dummyId = UUID.randomUUID().toString();
+        srt.doFromXContentTestWithRandomFields(
+            createTestItem(false, List.of(new GenericSearchExtBuilder(dummyId, GenericSearchExtBuilder.ValueType.SIMPLE))),
+            false
+        );
+    }
+
+    public void testFromXContentWithGenericSearchExtBuildersForMapValues() throws IOException {
+        srt.doFromXContentTestWithRandomFields(
+            createTestItem(false, List.of(new GenericSearchExtBuilder(Map.of("x", "y", "a", "b"), GenericSearchExtBuilder.ValueType.MAP))),
+            false
+        );
+    }
+
+    public void testFromXContentWithGenericSearchExtBuildersForListValues() throws IOException {
+        String dummyId = UUID.randomUUID().toString();
+        srt.doFromXContentTestWithRandomFields(
+            createTestItem(false, List.of(new GenericSearchExtBuilder(List.of("1", "2", "3"), GenericSearchExtBuilder.ValueType.LIST))),
+            false
+        );
+    }
+
+    public void testSerializationWithGenericSearchExtBuildersForSimpleValues() throws IOException {
+        String id = UUID.randomUUID().toString();
+        SearchResponse searchResponse = createTestItem(
+            false,
+            List.of(new GenericSearchExtBuilder(id, GenericSearchExtBuilder.ValueType.SIMPLE))
+        );
+        SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.CURRENT);
+        if (searchResponse.getHits().getTotalHits() == null) {
+            assertNull(deserialized.getHits().getTotalHits());
+        } else {
+            assertEquals(searchResponse.getHits().getTotalHits().value, deserialized.getHits().getTotalHits().value);
+            assertEquals(searchResponse.getHits().getTotalHits().relation, deserialized.getHits().getTotalHits().relation);
+        }
+        assertEquals(searchResponse.getHits().getHits().length, deserialized.getHits().getHits().length);
+        assertEquals(searchResponse.getNumReducePhases(), deserialized.getNumReducePhases());
+        assertEquals(searchResponse.getFailedShards(), deserialized.getFailedShards());
+        assertEquals(searchResponse.getTotalShards(), deserialized.getTotalShards());
+        assertEquals(searchResponse.getSkippedShards(), deserialized.getSkippedShards());
+        assertEquals(searchResponse.getClusters(), deserialized.getClusters());
+        assertEquals(
+            searchResponse.getInternalResponse().getSearchExtBuilders().get(0),
+            deserialized.getInternalResponse().getSearchExtBuilders().get(0)
+        );
+    }
+
+    public void testSerializationWithGenericSearchExtBuildersForMapValues() throws IOException {
+        SearchResponse searchResponse = createTestItem(
+            false,
+            List.of(new GenericSearchExtBuilder(Map.of("x", "y", "a", "b"), GenericSearchExtBuilder.ValueType.MAP))
+        );
+        SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.CURRENT);
+        if (searchResponse.getHits().getTotalHits() == null) {
+            assertNull(deserialized.getHits().getTotalHits());
+        } else {
+            assertEquals(searchResponse.getHits().getTotalHits().value, deserialized.getHits().getTotalHits().value);
+            assertEquals(searchResponse.getHits().getTotalHits().relation, deserialized.getHits().getTotalHits().relation);
+        }
+        assertEquals(searchResponse.getHits().getHits().length, deserialized.getHits().getHits().length);
+        assertEquals(searchResponse.getNumReducePhases(), deserialized.getNumReducePhases());
+        assertEquals(searchResponse.getFailedShards(), deserialized.getFailedShards());
+        assertEquals(searchResponse.getTotalShards(), deserialized.getTotalShards());
+        assertEquals(searchResponse.getSkippedShards(), deserialized.getSkippedShards());
+        assertEquals(searchResponse.getClusters(), deserialized.getClusters());
+        assertEquals(
+            searchResponse.getInternalResponse().getSearchExtBuilders().get(0),
+            deserialized.getInternalResponse().getSearchExtBuilders().get(0)
+        );
+    }
+
+    public void testSerializationWithGenericSearchExtBuildersForListValues() throws IOException {
+        SearchResponse searchResponse = createTestItem(
+            false,
+            List.of(new GenericSearchExtBuilder(List.of("1", "2", "3"), GenericSearchExtBuilder.ValueType.LIST))
+        );
+        SearchResponse deserialized = copyWriteable(searchResponse, namedWriteableRegistry, SearchResponse::new, Version.CURRENT);
+        if (searchResponse.getHits().getTotalHits() == null) {
+            assertNull(deserialized.getHits().getTotalHits());
+        } else {
+            assertEquals(searchResponse.getHits().getTotalHits().value, deserialized.getHits().getTotalHits().value);
+            assertEquals(searchResponse.getHits().getTotalHits().relation, deserialized.getHits().getTotalHits().relation);
+        }
+        assertEquals(searchResponse.getHits().getHits().length, deserialized.getHits().getHits().length);
+        assertEquals(searchResponse.getNumReducePhases(), deserialized.getNumReducePhases());
+        assertEquals(searchResponse.getFailedShards(), deserialized.getFailedShards());
+        assertEquals(searchResponse.getTotalShards(), deserialized.getTotalShards());
+        assertEquals(searchResponse.getSkippedShards(), deserialized.getSkippedShards());
+        assertEquals(searchResponse.getClusters(), deserialized.getClusters());
+        assertEquals(
+            searchResponse.getInternalResponse().getSearchExtBuilders().get(0),
+            deserialized.getInternalResponse().getSearchExtBuilders().get(0)
+        );
+    }
+
+    public SearchResponse createTestItem(
+        boolean minimal,
+        List<SearchExtBuilder> searchExtBuilders,
+        ShardSearchFailure... shardSearchFailures
+    ) {
+        boolean timedOut = randomBoolean();
+        Boolean terminatedEarly = randomBoolean() ? null : randomBoolean();
+        int numReducePhases = randomIntBetween(1, 10);
+        long tookInMillis = randomNonNegativeLong();
+        int totalShards = randomIntBetween(1, Integer.MAX_VALUE);
+        int successfulShards = randomIntBetween(0, totalShards);
+        int skippedShards = randomIntBetween(0, totalShards);
+        InternalSearchResponse internalSearchResponse;
+        if (minimal == false) {
+            SearchHits hits = SearchHitsTests.createTestItem(true, true);
+            InternalAggregations aggregations = aggregationsTests.createTestInstance();
+            Suggest suggest = SuggestTests.createTestItem();
+            SearchProfileShardResults profileShardResults = SearchProfileShardResultsTests.createTestItem();
+            internalSearchResponse = new InternalSearchResponse(
+                hits,
+                aggregations,
+                suggest,
+                profileShardResults,
+                timedOut,
+                terminatedEarly,
+                numReducePhases,
+                searchExtBuilders
+            );
+        } else {
+            internalSearchResponse = InternalSearchResponse.empty();
+        }
+
+        return new SearchResponse(
+            internalSearchResponse,
+            null,
+            totalShards,
+            successfulShards,
+            skippedShards,
+            tookInMillis,
+            shardSearchFailures,
+            randomBoolean() ? randomClusters() : SearchResponse.Clusters.EMPTY,
+            null
+        );
+    }
+
+    static SearchResponse.Clusters randomClusters() {
+        int totalClusters = randomIntBetween(0, 10);
+        int successfulClusters = randomIntBetween(0, totalClusters);
+        int skippedClusters = totalClusters - successfulClusters;
+        return new SearchResponse.Clusters(totalClusters, successfulClusters, skippedClusters);
+    }
+
+    static class SimpleValueSearchExtBuilder extends SearchExtBuilder {
+
+        static ParseField FIELD = new ParseField("simple_value");
+
+        private final String id;
+
+        public SimpleValueSearchExtBuilder(String id) {
+            assertNotNull(id);
+            this.id = id;
+        }
+
+        public SimpleValueSearchExtBuilder(StreamInput in) throws IOException {
+            this.id = in.readString();
+        }
+
+        public String getId() {
+            return this.id;
+        }
+
+        @Override
+        public String getWriteableName() {
+            return FIELD.getPreferredName();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(this.id);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.field(FIELD.getPreferredName(), id);
+        }
+
+        @Override
+        public int hashCode() {
+            return 0;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+
+            if (!(obj instanceof SimpleValueSearchExtBuilder)) {
+                return false;
+            }
+
+            return this.id.equals(((SimpleValueSearchExtBuilder) obj).getId());
+        }
+
+        public static SimpleValueSearchExtBuilder parse(XContentParser parser) throws IOException {
+            String id;
+            XContentParser.Token token = parser.currentToken();
+            if (token == XContentParser.Token.VALUE_STRING) {
+                id = parser.text();
+            } else {
+                throw new ParsingException(parser.getTokenLocation(), "Expected a VALUE_STRING but got " + token);
+            }
+            if (id == null) {
+                throw new ParsingException(parser.getTokenLocation(), "no id specified for " + FIELD.getPreferredName());
+            }
+            return new SimpleValueSearchExtBuilder(id);
+        }
+    }
+
+    static class MapSearchExtBuilder extends SearchExtBuilder {
+
+        private final static String EXT_FIELD = "map0";
+
+        private final Map<String, Object> map;
+
+        public MapSearchExtBuilder(Map<String, String> map) {
+            this.map = new HashMap<>();
+            for (Map.Entry<String, String> e : map.entrySet()) {
+                this.map.put(e.getKey(), e.getValue());
+            }
+        }
+
+        @Override
+        public String getWriteableName() {
+            return EXT_FIELD;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeMap(this.map);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.field(EXT_FIELD, this.map);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(this.getClass(), this.map);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            return false;
+        }
+    }
+
+    static class ListSearchExtBuilder extends SearchExtBuilder {
+
+        private final static String EXT_FIELD = "list0";
+
+        private final List<String> list;
+
+        public ListSearchExtBuilder(List<String> list) {
+            this.list = new ArrayList<>();
+            list.forEach(e -> this.list.add(e));
+        }
+
+        @Override
+        public String getWriteableName() {
+            return EXT_FIELD;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeCollection(this.list, StreamOutput::writeString);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.field(EXT_FIELD, this.list);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(this.getClass(), this.list);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            return false;
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/MultiValueModeTests.java b/server/src/test/java/org/opensearch/search/MultiValueModeTests.java
index bfb4466e53e43..948d2cffceabe 100644
--- a/server/src/test/java/org/opensearch/search/MultiValueModeTests.java
+++ b/server/src/test/java/org/opensearch/search/MultiValueModeTests.java
@@ -42,7 +42,7 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.index.fielddata.AbstractBinaryDocValues;
 import org.opensearch.index.fielddata.AbstractNumericDocValues;
 import org.opensearch.index.fielddata.AbstractSortedDocValues;
@@ -763,6 +763,11 @@ public BytesRef lookupOrd(long ord) {
             public long getValueCount() {
                 return 1 << 20;
             }
+
+            @Override
+            public int docValueCount() {
+                return array[doc].length;
+            }
         };
         verifySortedSet(multiValues, numDocs);
         final FixedBitSet rootDocs = randomRootDocs(numDocs);
diff --git a/server/src/test/java/org/opensearch/search/NestedIdentityTests.java b/server/src/test/java/org/opensearch/search/NestedIdentityTests.java
index a14f03eee7ef1..913434801c338 100644
--- a/server/src/test/java/org/opensearch/search/NestedIdentityTests.java
+++ b/server/src/test/java/org/opensearch/search/NestedIdentityTests.java
@@ -32,15 +32,14 @@
 
 package org.opensearch.search;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit.NestedIdentity;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -66,7 +65,7 @@ public static NestedIdentity createTestItem(int depth) {
     public void testFromXContent() throws IOException {
         NestedIdentity nestedIdentity = createTestItem(randomInt(3));
         XContentType xcontentType = randomFrom(XContentType.values());
-        XContentBuilder builder = XContentFactory.contentBuilder(xcontentType);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(xcontentType);
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -87,7 +86,7 @@ public void testToXContent() throws IOException {
         builder.endObject();
         assertEquals(
             "{\n" + "  \"_nested\" : {\n" + "    \"field\" : \"foo\",\n" + "    \"offset\" : 5\n" + "  }\n" + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
         nestedIdentity = new NestedIdentity("foo", 5, new NestedIdentity("bar", 3, null));
@@ -107,7 +106,7 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/search/SearchCancellationTests.java b/server/src/test/java/org/opensearch/search/SearchCancellationTests.java
index 1927558f94094..fce58eecbafb1 100644
--- a/server/src/test/java/org/opensearch/search/SearchCancellationTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchCancellationTests.java
@@ -38,27 +38,32 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.PointValues;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.TotalHitCountCollector;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.tests.util.TestUtil;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
 import org.apache.lucene.util.automaton.RegExp;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.tasks.TaskCancelledException;
+import org.opensearch.index.shard.IndexShard;
 import org.opensearch.search.internal.ContextIndexSearcher;
-import org.opensearch.tasks.TaskCancelledException;
+import org.opensearch.search.internal.SearchContext;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
+import org.junit.Before;
 import org.junit.BeforeClass;
 
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class SearchCancellationTests extends OpenSearchTestCase {
 
@@ -67,6 +72,7 @@ public class SearchCancellationTests extends OpenSearchTestCase {
 
     private static Directory dir;
     private static IndexReader reader;
+    private SearchContext searchContext;
 
     @BeforeClass
     public static void setup() throws IOException {
@@ -102,13 +108,21 @@ public static void cleanup() throws IOException {
         reader = null;
     }
 
+    @Before
+    public void testSetup() {
+        searchContext = mock(SearchContext.class);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
+    }
+
     public void testAddingCancellationActions() throws IOException {
         ContextIndexSearcher searcher = new ContextIndexSearcher(
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            null,
+            searchContext
         );
         NullPointerException npe = expectThrows(NullPointerException.class, () -> searcher.addQueryCancellation(null));
         assertEquals("cancellation runnable should not be null", npe.getMessage());
@@ -122,12 +136,16 @@ public void testAddingCancellationActions() throws IOException {
     public void testCancellableCollector() throws IOException {
         TotalHitCountCollector collector1 = new TotalHitCountCollector();
         Runnable cancellation = () -> { throw new TaskCancelledException("cancelled"); };
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
         ContextIndexSearcher searcher = new ContextIndexSearcher(
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            null,
+            searchContext
         );
 
         searcher.search(new MatchAllDocsQuery(), collector1);
@@ -154,7 +172,9 @@ public void testExitableDirectoryReader() throws IOException {
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            null,
+            searchContext
         );
         searcher.addQueryCancellation(cancellation);
         CompiledAutomaton automaton = new CompiledAutomaton(new RegExp("a.*").toAutomaton());
diff --git a/server/src/test/java/org/opensearch/search/SearchHitTests.java b/server/src/test/java/org/opensearch/search/SearchHitTests.java
index 8307b7faa71f1..88d5fb38a6cb1 100644
--- a/server/src/test/java/org/opensearch/search/SearchHitTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchHitTests.java
@@ -36,19 +36,20 @@
 import org.apache.lucene.search.TotalHits;
 import org.opensearch.Version;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.get.GetResultTests;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.SearchHit.NestedIdentity;
 import org.opensearch.search.fetch.subphase.highlight.HighlightField;
 import org.opensearch.search.fetch.subphase.highlight.HighlightFieldTests;
@@ -64,7 +65,7 @@
 import java.util.Map;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 import static org.hamcrest.Matchers.containsString;
@@ -79,7 +80,7 @@ public static SearchHit createTestItem(boolean withOptionalInnerHits, boolean wi
         return createTestItem(randomFrom(XContentType.values()), withOptionalInnerHits, withShardTarget);
     }
 
-    public static SearchHit createTestItem(XContentType xContentType, boolean withOptionalInnerHits, boolean transportSerialization) {
+    public static SearchHit createTestItem(final MediaType mediaType, boolean withOptionalInnerHits, boolean transportSerialization) {
         int internalId = randomInt();
         String uid = randomAlphaOfLength(10);
         NestedIdentity nestedIdentity = null;
@@ -90,8 +91,8 @@ public static SearchHit createTestItem(XContentType xContentType, boolean withOp
         Map<String, DocumentField> documentFields = new HashMap<>();
         if (frequently()) {
             if (randomBoolean()) {
-                metaFields = GetResultTests.randomDocumentFields(xContentType, true).v2();
-                documentFields = GetResultTests.randomDocumentFields(xContentType, false).v2();
+                metaFields = GetResultTests.randomDocumentFields(mediaType, true).v2();
+                documentFields = GetResultTests.randomDocumentFields(mediaType, false).v2();
             }
         }
 
@@ -104,7 +105,7 @@ public static SearchHit createTestItem(XContentType xContentType, boolean withOp
             }
         }
         if (frequently()) {
-            hit.sourceRef(RandomObjects.randomSource(random(), xContentType));
+            hit.sourceRef(RandomObjects.randomSource(random(), mediaType));
         }
         if (randomBoolean()) {
             hit.version(randomLong());
@@ -115,7 +116,7 @@ public static SearchHit createTestItem(XContentType xContentType, boolean withOp
             hit.version(randomLongBetween(1, Long.MAX_VALUE));
         }
         if (randomBoolean()) {
-            hit.sortValues(SearchSortValuesTests.createTestItem(xContentType, transportSerialization));
+            hit.sortValues(SearchSortValuesTests.createTestItem(mediaType, transportSerialization));
         }
         if (randomBoolean()) {
             int size = randomIntBetween(0, 5);
@@ -142,7 +143,7 @@ public static SearchHit createTestItem(XContentType xContentType, boolean withOp
             if (innerHitsSize > 0) {
                 Map<String, SearchHits> innerHits = new HashMap<>(innerHitsSize);
                 for (int i = 0; i < innerHitsSize; i++) {
-                    innerHits.put(randomAlphaOfLength(5), SearchHitsTests.createTestItem(xContentType, false, transportSerialization));
+                    innerHits.put(randomAlphaOfLength(5), SearchHitsTests.createTestItem(mediaType, false, transportSerialization));
                 }
                 hit.setInnerHits(innerHits);
             }
@@ -240,7 +241,7 @@ public void testToXContent() throws IOException {
         searchHit.score(1.5f);
         XContentBuilder builder = JsonXContent.contentBuilder();
         searchHit.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals("{\"_id\":\"id1\",\"_score\":1.5}", Strings.toString(builder));
+        assertEquals("{\"_id\":\"id1\",\"_score\":1.5}", builder.toString());
     }
 
     public void testSerializeShardTarget() throws Exception {
@@ -319,7 +320,7 @@ public void testHasSource() {
     public void testWeirdScriptFields() throws Exception {
         {
             XContentParser parser = createParser(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 "{\n"
                     + "  \"_index\": \"twitter\",\n"
                     + "  \"_id\": \"1\",\n"
@@ -339,7 +340,7 @@ public void testWeirdScriptFields() throws Exception {
         }
         {
             XContentParser parser = createParser(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 "{\n"
                     + "  \"_index\": \"twitter\",\n"
                     + "  \"_id\": \"1\",\n"
@@ -395,11 +396,11 @@ public void testToXContentEmptyFields() throws IOException {
         fields.put("bar", new DocumentField("bar", Collections.emptyList()));
         SearchHit hit = new SearchHit(0, "_id", null, fields, Collections.emptyMap());
         {
-            BytesReference originalBytes = toShuffledXContent(hit, XContentType.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
+            BytesReference originalBytes = toShuffledXContent(hit, MediaTypeRegistry.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
             // checks that the fields section is completely omitted in the rendering.
             assertThat(originalBytes.utf8ToString(), not(containsString("fields")));
             final SearchHit parsed;
-            try (XContentParser parser = createParser(XContentType.JSON.xContent(), originalBytes)) {
+            try (XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), originalBytes)) {
                 parser.nextToken(); // jump to first START_OBJECT
                 parsed = SearchHit.fromXContent(parser);
                 assertEquals(XContentParser.Token.END_OBJECT, parser.currentToken());
@@ -413,9 +414,9 @@ public void testToXContentEmptyFields() throws IOException {
         fields.put("bar", new DocumentField("bar", Collections.singletonList("value")));
         hit = new SearchHit(0, "_id", null, fields, Collections.emptyMap());
         {
-            BytesReference originalBytes = toShuffledXContent(hit, XContentType.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
+            BytesReference originalBytes = toShuffledXContent(hit, MediaTypeRegistry.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
             final SearchHit parsed;
-            try (XContentParser parser = createParser(XContentType.JSON.xContent(), originalBytes)) {
+            try (XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), originalBytes)) {
                 parser.nextToken(); // jump to first START_OBJECT
                 parsed = SearchHit.fromXContent(parser);
                 assertEquals(XContentParser.Token.END_OBJECT, parser.currentToken());
@@ -429,9 +430,9 @@ public void testToXContentEmptyFields() throws IOException {
         metadata.put("_routing", new DocumentField("_routing", Collections.emptyList()));
         hit = new SearchHit(0, "_id", null, fields, Collections.emptyMap());
         {
-            BytesReference originalBytes = toShuffledXContent(hit, XContentType.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
+            BytesReference originalBytes = toShuffledXContent(hit, MediaTypeRegistry.JSON, ToXContent.EMPTY_PARAMS, randomBoolean());
             final SearchHit parsed;
-            try (XContentParser parser = createParser(XContentType.JSON.xContent(), originalBytes)) {
+            try (XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), originalBytes)) {
                 parser.nextToken(); // jump to first START_OBJECT
                 parsed = SearchHit.fromXContent(parser);
                 assertEquals(XContentParser.Token.END_OBJECT, parser.currentToken());
diff --git a/server/src/test/java/org/opensearch/search/SearchHitsTests.java b/server/src/test/java/org/opensearch/search/SearchHitsTests.java
index 11df58c4ee7c7..fd3ba35a4d3bb 100644
--- a/server/src/test/java/org/opensearch/search/SearchHitsTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchHitsTests.java
@@ -36,18 +36,18 @@
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.action.OriginalIndices;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.LuceneTests;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -62,13 +62,13 @@ public static SearchHits createTestItem(boolean withOptionalInnerHits, boolean w
 
     private static SearchHit[] createSearchHitArray(
         int size,
-        XContentType xContentType,
+        final MediaType mediaType,
         boolean withOptionalInnerHits,
         boolean transportSerialization
     ) {
         SearchHit[] hits = new SearchHit[size];
         for (int i = 0; i < hits.length; i++) {
-            hits[i] = SearchHitTests.createTestItem(xContentType, withOptionalInnerHits, transportSerialization);
+            hits[i] = SearchHitTests.createTestItem(mediaType, withOptionalInnerHits, transportSerialization);
         }
         return hits;
     }
@@ -78,18 +78,18 @@ private static TotalHits randomTotalHits(TotalHits.Relation relation) {
         return new TotalHits(totalHits, relation);
     }
 
-    public static SearchHits createTestItem(XContentType xContentType, boolean withOptionalInnerHits, boolean transportSerialization) {
-        return createTestItem(xContentType, withOptionalInnerHits, transportSerialization, randomFrom(TotalHits.Relation.values()));
+    public static SearchHits createTestItem(final MediaType mediaType, boolean withOptionalInnerHits, boolean transportSerialization) {
+        return createTestItem(mediaType, withOptionalInnerHits, transportSerialization, randomFrom(TotalHits.Relation.values()));
     }
 
     private static SearchHits createTestItem(
-        XContentType xContentType,
+        final MediaType mediaType,
         boolean withOptionalInnerHits,
         boolean transportSerialization,
         TotalHits.Relation totalHitsRelation
     ) {
         int searchHits = randomIntBetween(0, 5);
-        SearchHit[] hits = createSearchHitArray(searchHits, xContentType, withOptionalInnerHits, transportSerialization);
+        SearchHit[] hits = createSearchHitArray(searchHits, mediaType, withOptionalInnerHits, transportSerialization);
         TotalHits totalHits = frequently() ? randomTotalHits(totalHitsRelation) : null;
         float maxScore = frequently() ? randomFloat() : Float.NaN;
         SortField[] sortFields = null;
@@ -224,13 +224,13 @@ protected SearchHits createTestInstance() {
     }
 
     @Override
-    protected SearchHits createXContextTestInstance(XContentType xContentType) {
+    protected SearchHits createXContextTestInstance(final MediaType mediaType) {
         // We don't set SearchHit#shard (withShardTarget is false) in this test
         // because the rest serialization does not render this information so the
         // deserialized hit cannot be equal to the original instance.
         // There is another test (#testFromXContentWithShards) that checks the
         // rest serialization with shard targets.
-        return createTestItem(xContentType, true, false);
+        return createTestItem(mediaType, true, false);
     }
 
     @Override
@@ -261,7 +261,7 @@ public void testToXContent() throws IOException {
             "{\"hits\":{\"total\":{\"value\":1000,\"relation\":\"eq\"},\"max_score\":1.5,"
                 + "\"hits\":[{\"_id\":\"id1\",\"_score\":null},"
                 + "{\"_id\":\"id2\",\"_score\":null}]}}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/search/SearchModuleTests.java b/server/src/test/java/org/opensearch/search/SearchModuleTests.java
index 05d4153949f9a..bb329fc591d9f 100644
--- a/server/src/test/java/org/opensearch/search/SearchModuleTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchModuleTests.java
@@ -33,13 +33,14 @@
 
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.util.CharsRefBuilder;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
@@ -50,6 +51,8 @@
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
 import org.opensearch.search.aggregations.AggregatorFactory;
 import org.opensearch.search.aggregations.BaseAggregationBuilder;
+import org.opensearch.search.aggregations.ConcurrentAggregationProcessor;
+import org.opensearch.search.aggregations.DefaultAggregationProcessor;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.InternalAggregation.ReduceContext;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
@@ -74,6 +77,10 @@
 import org.opensearch.search.fetch.subphase.highlight.Highlighter;
 import org.opensearch.search.fetch.subphase.highlight.PlainHighlighter;
 import org.opensearch.search.fetch.subphase.highlight.UnifiedHighlighter;
+import org.opensearch.search.query.ConcurrentQueryPhaseSearcher;
+import org.opensearch.search.query.QueryPhase;
+import org.opensearch.search.query.QueryPhaseSearcher;
+import org.opensearch.search.query.QueryPhaseSearcherWrapper;
 import org.opensearch.search.rescore.QueryRescorerBuilder;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.rescore.RescorerBuilder;
@@ -87,6 +94,8 @@
 import org.opensearch.search.suggest.term.TermSuggestion;
 import org.opensearch.search.suggest.term.TermSuggestionBuilder;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.TestSearchContext;
+import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -94,6 +103,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 import static java.util.Collections.emptyList;
@@ -103,6 +113,9 @@
 import static java.util.stream.Collectors.toSet;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.hasSize;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 public class SearchModuleTests extends OpenSearchTestCase {
 
@@ -416,6 +429,97 @@ public List<RescorerSpec<?>> getRescorers() {
         );
     }
 
+    public void testDefaultQueryPhaseSearcher() {
+        SearchModule searchModule = new SearchModule(Settings.EMPTY, Collections.emptyList());
+        TestSearchContext searchContext = new TestSearchContext(null);
+        QueryPhase queryPhase = searchModule.getQueryPhase();
+        assertTrue(queryPhase.getQueryPhaseSearcher() instanceof QueryPhaseSearcherWrapper);
+        assertTrue(queryPhase.getQueryPhaseSearcher().aggregationProcessor(searchContext) instanceof DefaultAggregationProcessor);
+    }
+
+    public void testConcurrentQueryPhaseSearcher() {
+        Settings settings = Settings.builder().put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, true).build();
+        FeatureFlags.initializeFeatureFlags(settings);
+        SearchModule searchModule = new SearchModule(settings, Collections.emptyList());
+        TestSearchContext searchContext = new TestSearchContext(null);
+        searchContext.setConcurrentSegmentSearchEnabled(true);
+        QueryPhase queryPhase = searchModule.getQueryPhase();
+        assertTrue(queryPhase.getQueryPhaseSearcher() instanceof QueryPhaseSearcherWrapper);
+        assertTrue(queryPhase.getQueryPhaseSearcher().aggregationProcessor(searchContext) instanceof ConcurrentAggregationProcessor);
+        FeatureFlags.initializeFeatureFlags(Settings.EMPTY);
+    }
+
+    public void testPluginQueryPhaseSearcher() {
+        Settings settings = Settings.builder().put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, true).build();
+        FeatureFlags.initializeFeatureFlags(settings);
+        QueryPhaseSearcher queryPhaseSearcher = (searchContext, searcher, query, collectors, hasFilterCollector, hasTimeout) -> false;
+        SearchPlugin plugin1 = new SearchPlugin() {
+            @Override
+            public Optional<QueryPhaseSearcher> getQueryPhaseSearcher() {
+                return Optional.of(queryPhaseSearcher);
+            }
+        };
+        SearchModule searchModule = new SearchModule(settings, Collections.singletonList(plugin1));
+        QueryPhase queryPhase = searchModule.getQueryPhase();
+        TestSearchContext searchContext = new TestSearchContext(null);
+        assertEquals(queryPhaseSearcher, queryPhase.getQueryPhaseSearcher());
+        assertTrue(queryPhaseSearcher.aggregationProcessor(searchContext) instanceof DefaultAggregationProcessor);
+        FeatureFlags.initializeFeatureFlags(Settings.EMPTY);
+    }
+
+    public void testMultiplePluginRegisterQueryPhaseSearcher() {
+        SearchPlugin plugin1 = new SearchPlugin() {
+            @Override
+            public Optional<QueryPhaseSearcher> getQueryPhaseSearcher() {
+                return Optional.of(mock(QueryPhaseSearcher.class));
+            }
+        };
+        SearchPlugin plugin2 = new SearchPlugin() {
+            @Override
+            public Optional<QueryPhaseSearcher> getQueryPhaseSearcher() {
+                return Optional.of(new ConcurrentQueryPhaseSearcher());
+            }
+        };
+        List<SearchPlugin> searchPlugins = new ArrayList<>();
+        searchPlugins.add(plugin1);
+        searchPlugins.add(plugin2);
+        expectThrows(IllegalStateException.class, () -> new SearchModule(Settings.EMPTY, searchPlugins));
+    }
+
+    public void testIndexSearcher() {
+        SearchModule searchModule = new SearchModule(Settings.EMPTY, Collections.emptyList());
+        ThreadPool threadPool = mock(ThreadPool.class);
+        assertNull(searchModule.getIndexSearcherExecutor(threadPool));
+        verify(threadPool, times(0)).executor(ThreadPool.Names.INDEX_SEARCHER);
+
+        // enable concurrent segment search feature flag
+        Settings settings = Settings.builder().put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, true).build();
+        FeatureFlags.initializeFeatureFlags(settings);
+        searchModule = new SearchModule(settings, Collections.emptyList());
+        searchModule.getIndexSearcherExecutor(threadPool);
+        verify(threadPool).executor(ThreadPool.Names.INDEX_SEARCHER);
+        FeatureFlags.initializeFeatureFlags(Settings.EMPTY);
+    }
+
+    public void testMultiplePluginRegisterIndexSearcherProvider() {
+        SearchPlugin plugin1 = new SearchPlugin() {
+            @Override
+            public Optional<ExecutorServiceProvider> getIndexSearcherExecutorProvider() {
+                return Optional.of(mock(ExecutorServiceProvider.class));
+            }
+        };
+        SearchPlugin plugin2 = new SearchPlugin() {
+            @Override
+            public Optional<ExecutorServiceProvider> getIndexSearcherExecutorProvider() {
+                return Optional.of(mock(ExecutorServiceProvider.class));
+            }
+        };
+        List<SearchPlugin> searchPlugins = new ArrayList<>();
+        searchPlugins.add(plugin1);
+        searchPlugins.add(plugin2);
+        expectThrows(IllegalStateException.class, () -> new SearchModule(Settings.EMPTY, searchPlugins));
+    }
+
     private static final String[] NON_DEPRECATED_QUERIES = new String[] {
         "bool",
         "boosting",
diff --git a/server/src/test/java/org/opensearch/search/SearchServiceTests.java b/server/src/test/java/org/opensearch/search/SearchServiceTests.java
index 4e342875e4599..390f032ef4a79 100644
--- a/server/src/test/java/org/opensearch/search/SearchServiceTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchServiceTests.java
@@ -31,33 +31,41 @@
 
 package org.opensearch.search;
 
-import com.carrotsearch.hppc.IntArrayList;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.ClearScrollRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.action.search.PitSearchContextIdForNode;
+import org.opensearch.action.search.SearchContextIdForNode;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.action.search.SearchType;
+import org.opensearch.action.search.UpdatePitContextRequest;
+import org.opensearch.action.search.UpdatePitContextResponse;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.WriteRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.index.IndexService;
@@ -73,12 +81,10 @@
 import org.opensearch.index.search.stats.SearchStats;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.SearchOperationListener;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.settings.InternalOrPrivateSettingsPlugin;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.MockScriptPlugin;
 import org.opensearch.script.Script;
@@ -98,6 +104,9 @@
 import org.opensearch.search.internal.ShardSearchContextId;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.sort.FieldSortBuilder;
+import org.opensearch.search.sort.MinAndMax;
+import org.opensearch.search.sort.SortOrder;
 import org.opensearch.search.suggest.SuggestBuilder;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.threadpool.ThreadPool;
@@ -215,6 +224,11 @@ public void onQueryPhase(SearchContext context, long tookInNanos) {
         }
     }
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     protected Settings nodeSettings() {
         return Settings.builder().put("search.default_search_timeout", "5s").build();
@@ -349,7 +363,7 @@ public void onFailure(Exception e) {
                             result
                         );
                         SearchPhaseResult searchPhaseResult = result.get();
-                        IntArrayList intCursors = new IntArrayList(1);
+                        List<Integer> intCursors = new ArrayList(1);
                         intCursors.add(0);
                         ShardFetchRequest req = new ShardFetchRequest(searchPhaseResult.getContextId(), intCursors, null/* not a scroll */);
                         PlainActionFuture<FetchSearchResult> listener = new PlainActionFuture<>();
@@ -735,13 +749,9 @@ public void testOpenScrollContextsConcurrently() throws Exception {
     public static class FailOnRewriteQueryPlugin extends Plugin implements SearchPlugin {
         @Override
         public List<QuerySpec<?>> getQueries() {
-            return singletonList(
-                new QuerySpec<>(
-                    "fail_on_rewrite_query",
-                    FailOnRewriteQueryBuilder::new,
-                    parseContext -> { throw new UnsupportedOperationException("No query parser for this plugin"); }
-                )
-            );
+            return singletonList(new QuerySpec<>("fail_on_rewrite_query", FailOnRewriteQueryBuilder::new, parseContext -> {
+                throw new UnsupportedOperationException("No query parser for this plugin");
+            }));
         }
     }
 
@@ -1123,7 +1133,7 @@ public void testExpandSearchFrozen() {
 
     public void testCreateReduceContext() {
         SearchService service = getInstanceFromNode(SearchService.class);
-        InternalAggregation.ReduceContextBuilder reduceContextBuilder = service.aggReduceContextBuilder(new SearchRequest());
+        InternalAggregation.ReduceContextBuilder reduceContextBuilder = service.aggReduceContextBuilder(new SearchSourceBuilder());
         {
             InternalAggregation.ReduceContext reduceContext = reduceContextBuilder.forFinalReduction();
             expectThrows(
@@ -1171,6 +1181,180 @@ public void testCreateSearchContext() throws IOException {
         }
     }
 
+    /**
+     * Test that the Search Context for concurrent segment search enabled is set correctly based on both
+     * index and cluster settings.
+     */
+    public void testConcurrentSegmentSearchSearchContext() throws IOException {
+        Boolean[][] scenarios = {
+            // cluster setting, index setting, concurrent search enabled?
+            { null, null, true },
+            { null, false, false },
+            { null, true, true },
+            { true, null, true },
+            { true, false, false },
+            { true, true, true },
+            { false, null, false },
+            { false, false, false },
+            { false, true, true } };
+
+        String index = randomAlphaOfLengthBetween(5, 10).toLowerCase(Locale.ROOT);
+        IndexService indexService = createIndex(index);
+        final SearchService service = getInstanceFromNode(SearchService.class);
+        ShardId shardId = new ShardId(indexService.index(), 0);
+        long nowInMillis = System.currentTimeMillis();
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(3, 10);
+        SearchRequest searchRequest = new SearchRequest();
+        searchRequest.allowPartialSearchResults(randomBoolean());
+        ShardSearchRequest request = new ShardSearchRequest(
+            OriginalIndices.NONE,
+            searchRequest,
+            shardId,
+            indexService.numberOfShards(),
+            AliasFilter.EMPTY,
+            1f,
+            nowInMillis,
+            clusterAlias,
+            Strings.EMPTY_ARRAY
+        );
+
+        for (Boolean[] scenario : scenarios) {
+            Boolean clusterSetting = scenario[0];
+            Boolean indexSetting = scenario[1];
+            Boolean concurrentSearchEnabled = scenario[2];
+
+            if (clusterSetting == null) {
+                client().admin()
+                    .cluster()
+                    .prepareUpdateSettings()
+                    .setTransientSettings(Settings.builder().putNull(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey()))
+                    .get();
+            } else {
+                client().admin()
+                    .cluster()
+                    .prepareUpdateSettings()
+                    .setTransientSettings(
+                        Settings.builder().put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), clusterSetting)
+                    )
+                    .get();
+            }
+
+            if (indexSetting == null) {
+                client().admin()
+                    .indices()
+                    .prepareUpdateSettings(index)
+                    .setSettings(Settings.builder().putNull(IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey()))
+                    .get();
+            } else {
+                client().admin()
+                    .indices()
+                    .prepareUpdateSettings(index)
+                    .setSettings(Settings.builder().put(IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), indexSetting))
+                    .get();
+            }
+
+            try (DefaultSearchContext searchContext = service.createSearchContext(request, new TimeValue(System.currentTimeMillis()))) {
+                assertEquals(
+                    clusterSetting,
+                    client().admin()
+                        .cluster()
+                        .prepareState()
+                        .get()
+                        .getState()
+                        .getMetadata()
+                        .transientSettings()
+                        .getAsBoolean(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), null)
+                );
+                assertEquals(
+                    indexSetting == null ? null : indexSetting.toString(),
+                    client().admin()
+                        .indices()
+                        .prepareGetSettings(index)
+                        .get()
+                        .getSetting(index, IndexSettings.INDEX_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey())
+                );
+                searchContext.evaluateRequestShouldUseConcurrentSearch();
+                assertEquals(concurrentSearchEnabled, searchContext.shouldUseConcurrentSearch());
+                // verify executor nullability with concurrent search enabled/disabled
+                if (concurrentSearchEnabled) {
+                    assertNotNull(searchContext.searcher().getExecutor());
+                } else {
+                    assertNull(searchContext.searcher().getExecutor());
+                }
+            }
+        }
+        // Cleanup
+        client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().putNull(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey()))
+            .get();
+    }
+
+    /**
+     * Test that the Search Context for concurrent segment search enabled is set correctly at the time of construction.
+     * The same is used throughout the context object lifetime even if cluster setting changes before the request completion.
+     */
+    public void testConcurrentSegmentSearchIsSetOnceDuringContextCreation() throws IOException {
+        String index = randomAlphaOfLengthBetween(5, 10).toLowerCase(Locale.ROOT);
+        IndexService indexService = createIndex(index);
+        final SearchService service = getInstanceFromNode(SearchService.class);
+        ShardId shardId = new ShardId(indexService.index(), 0);
+        long nowInMillis = System.currentTimeMillis();
+        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(3, 10);
+        SearchRequest searchRequest = new SearchRequest();
+        searchRequest.allowPartialSearchResults(randomBoolean());
+        ShardSearchRequest request = new ShardSearchRequest(
+            OriginalIndices.NONE,
+            searchRequest,
+            shardId,
+            indexService.numberOfShards(),
+            AliasFilter.EMPTY,
+            1f,
+            nowInMillis,
+            clusterAlias,
+            Strings.EMPTY_ARRAY
+        );
+
+        Boolean[] concurrentSearchStates = new Boolean[] { true, false };
+        for (Boolean concurrentSearchSetting : concurrentSearchStates) {
+            // update concurrent search cluster setting and create search context
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setTransientSettings(
+                    Settings.builder().put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), concurrentSearchSetting)
+                )
+                .get();
+            try (DefaultSearchContext searchContext = service.createSearchContext(request, new TimeValue(System.currentTimeMillis()))) {
+                // verify concurrent search state in context
+                searchContext.evaluateRequestShouldUseConcurrentSearch();
+                assertEquals(concurrentSearchSetting, searchContext.shouldUseConcurrentSearch());
+                // verify executor state in searcher
+                assertEquals(concurrentSearchSetting, (searchContext.searcher().getExecutor() != null));
+
+                // update cluster setting to flip the concurrent segment search state
+                client().admin()
+                    .cluster()
+                    .prepareUpdateSettings()
+                    .setTransientSettings(
+                        Settings.builder().put(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), !concurrentSearchSetting)
+                    )
+                    .get();
+
+                // verify that concurrent segment search is still set to same expected value for the context
+                assertEquals(concurrentSearchSetting, searchContext.shouldUseConcurrentSearch());
+            }
+        }
+
+        // Cleanup
+        client().admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setTransientSettings(Settings.builder().putNull(SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey()))
+            .get();
+    }
+
     /**
      * While we have no NPE in DefaultContext constructor anymore, we still want to guard against it (or other failures) in the future to
      * avoid leaking searchers.
@@ -1406,9 +1590,10 @@ public void testOpenReaderContext() {
         createIndex("index");
         SearchService searchService = getInstanceFromNode(SearchService.class);
         PlainActionFuture<ShardSearchContextId> future = new PlainActionFuture<>();
-        searchService.openReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueMinutes(between(1, 10)), future);
+        searchService.createPitReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueMinutes(between(1, 10)), future);
         future.actionGet();
         assertThat(searchService.getActiveContexts(), equalTo(1));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(1));
         assertTrue(searchService.freeReaderContext(future.actionGet()));
     }
 
@@ -1422,4 +1607,251 @@ private ReaderContext createReaderContext(IndexService indexService, IndexShard
             false
         );
     }
+
+    public void testDeletePitReaderContext() throws ExecutionException, InterruptedException {
+        createIndex("index");
+        SearchService searchService = getInstanceFromNode(SearchService.class);
+        PlainActionFuture<ShardSearchContextId> future = new PlainActionFuture<>();
+        searchService.createPitReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueMinutes(between(1, 10)), future);
+        List<PitSearchContextIdForNode> contextIds = new ArrayList<>();
+        ShardSearchContextId shardSearchContextId = future.actionGet();
+        PitSearchContextIdForNode pitSearchContextIdForNode = new PitSearchContextIdForNode(
+            "1",
+            new SearchContextIdForNode(null, "node1", shardSearchContextId)
+        );
+        contextIds.add(pitSearchContextIdForNode);
+
+        assertThat(searchService.getActiveContexts(), equalTo(1));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(1));
+        validatePitStats("index", 1, 0, 0);
+        DeletePitResponse deletePitResponse = searchService.freeReaderContextsIfFound(contextIds);
+        assertTrue(deletePitResponse.getDeletePitResults().get(0).isSuccessful());
+        // assert true for reader context not found
+        deletePitResponse = searchService.freeReaderContextsIfFound(contextIds);
+        assertTrue(deletePitResponse.getDeletePitResults().get(0).isSuccessful());
+        // adding this assert to showcase behavior difference
+        assertFalse(searchService.freeReaderContext(future.actionGet()));
+        validatePitStats("index", 0, 1, 0);
+    }
+
+    public void testPitContextMaxKeepAlive() {
+        createIndex("index");
+        SearchService searchService = getInstanceFromNode(SearchService.class);
+        PlainActionFuture<ShardSearchContextId> future = new PlainActionFuture<>();
+
+        IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> {
+            searchService.createPitReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueHours(25), future);
+            future.actionGet();
+        });
+        assertEquals(
+            "Keep alive for request (1d) is too large. "
+                + "It must be less than ("
+                + SearchService.MAX_PIT_KEEPALIVE_SETTING.get(Settings.EMPTY)
+                + "). "
+                + "This limit can be set by changing the ["
+                + SearchService.MAX_PIT_KEEPALIVE_SETTING.getKey()
+                + "] cluster level setting.",
+            ex.getMessage()
+        );
+        assertThat(searchService.getActiveContexts(), equalTo(0));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(0));
+    }
+
+    public void testUpdatePitId() throws ExecutionException, InterruptedException {
+        createIndex("index");
+        SearchService searchService = getInstanceFromNode(SearchService.class);
+        PlainActionFuture<ShardSearchContextId> future = new PlainActionFuture<>();
+        searchService.createPitReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueMinutes(between(1, 10)), future);
+        ShardSearchContextId id = future.actionGet();
+        PlainActionFuture<UpdatePitContextResponse> updateFuture = new PlainActionFuture<>();
+        UpdatePitContextRequest updateRequest = new UpdatePitContextRequest(
+            id,
+            "pitId",
+            TimeValue.timeValueMinutes(between(1, 10)).millis(),
+            System.currentTimeMillis()
+        );
+        searchService.updatePitIdAndKeepAlive(updateRequest, updateFuture);
+        UpdatePitContextResponse updateResponse = updateFuture.actionGet();
+        assertTrue(updateResponse.getPitId().equalsIgnoreCase("pitId"));
+        assertTrue(updateResponse.getCreationTime() == updateRequest.getCreationTime());
+        assertTrue(updateResponse.getKeepAlive() == updateRequest.getKeepAlive());
+        assertTrue(updateResponse.getPitId().equalsIgnoreCase("pitId"));
+        assertThat(searchService.getActiveContexts(), equalTo(1));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(1));
+        validatePitStats("index", 1, 0, 0);
+        assertTrue(searchService.freeReaderContext(future.actionGet()));
+        validatePitStats("index", 0, 1, 0);
+    }
+
+    public void testUpdatePitIdMaxKeepAlive() {
+        createIndex("index");
+        SearchService searchService = getInstanceFromNode(SearchService.class);
+        PlainActionFuture<ShardSearchContextId> future = new PlainActionFuture<>();
+        searchService.createPitReaderContext(new ShardId(resolveIndex("index"), 0), TimeValue.timeValueMinutes(between(1, 10)), future);
+        ShardSearchContextId id = future.actionGet();
+
+        UpdatePitContextRequest updateRequest = new UpdatePitContextRequest(
+            id,
+            "pitId",
+            TimeValue.timeValueHours(25).millis(),
+            System.currentTimeMillis()
+        );
+        IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> {
+            PlainActionFuture<UpdatePitContextResponse> updateFuture = new PlainActionFuture<>();
+            searchService.updatePitIdAndKeepAlive(updateRequest, updateFuture);
+        });
+
+        assertEquals(
+            "Keep alive for request (1d) is too large. "
+                + "It must be less than ("
+                + SearchService.MAX_PIT_KEEPALIVE_SETTING.get(Settings.EMPTY)
+                + "). "
+                + "This limit can be set by changing the ["
+                + SearchService.MAX_PIT_KEEPALIVE_SETTING.getKey()
+                + "] cluster level setting.",
+            ex.getMessage()
+        );
+        assertThat(searchService.getActiveContexts(), equalTo(1));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(1));
+        assertTrue(searchService.freeReaderContext(future.actionGet()));
+    }
+
+    public void testUpdatePitIdWithInvalidReaderId() {
+        SearchService searchService = getInstanceFromNode(SearchService.class);
+        ShardSearchContextId id = new ShardSearchContextId("session", 9);
+
+        UpdatePitContextRequest updateRequest = new UpdatePitContextRequest(
+            id,
+            "pitId",
+            TimeValue.timeValueHours(23).millis(),
+            System.currentTimeMillis()
+        );
+        SearchContextMissingException ex = expectThrows(SearchContextMissingException.class, () -> {
+            PlainActionFuture<UpdatePitContextResponse> updateFuture = new PlainActionFuture<>();
+            searchService.updatePitIdAndKeepAlive(updateRequest, updateFuture);
+        });
+
+        assertEquals("No search context found for id [" + id.getId() + "]", ex.getMessage());
+        assertThat(searchService.getActiveContexts(), equalTo(0));
+        assertThat(searchService.getAllPITReaderContexts().size(), equalTo(0));
+    }
+
+    public void validatePitStats(String index, long expectedPitCurrent, long expectedPitCount, int shardId) throws ExecutionException,
+        InterruptedException {
+        IndicesService indicesService = getInstanceFromNode(IndicesService.class);
+        IndexService indexService = indicesService.indexServiceSafe(resolveIndex(index));
+        IndexShard indexShard = indexService.getShard(shardId);
+        assertEquals(expectedPitCurrent, indexShard.searchStats().getTotal().getPitCurrent());
+        assertEquals(expectedPitCount, indexShard.searchStats().getTotal().getPitCount());
+    }
+
+    /**
+     * Test for ASC order search_after query.
+     * Min = 0L, Max = 9L, search_after = 10L
+     * Expected result is canMatch = false
+     */
+    public void testCanMatchSearchAfterAscGreaterThanMax() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { 10L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.ASC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), false);
+    }
+
+    /**
+     * Test for ASC order search_after query.
+     * Min = 0L, Max = 9L, search_after = 7L
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterAscLessThanMax() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { 7L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.ASC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), true);
+    }
+
+    /**
+     * Test for ASC order search_after query.
+     * Min = 0L, Max = 9L, search_after = 9L
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterAscEqualMax() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { 9L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.ASC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), true);
+    }
+
+    /**
+     * Test for DESC order search_after query.
+     * Min = 0L, Max = 9L, search_after = 10L
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterDescGreaterThanMin() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { 10L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.DESC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), true);
+    }
+
+    /**
+     * Test for DESC order search_after query.
+     * Min = 0L, Max = 9L, search_after = -1L
+     * Expected result is canMatch = false
+     */
+    public void testCanMatchSearchAfterDescLessThanMin() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { -1L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.DESC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), false);
+    }
+
+    /**
+     * Test for DESC order search_after query.
+     * Min = 0L, Max = 9L, search_after = 0L
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterDescEqualMin() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { 0L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.DESC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), true);
+    }
+
+    /**
+     * Test canMatchSearchAfter with missing value, even if min/max is out of range
+     * Min = 0L, Max = 9L, search_after = -1L
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterWithMissing() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { -1L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.DESC);
+        // Should be false without missing values
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), false);
+        primarySort.missing("_last");
+        // Should be true with missing values
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, SearchContext.TRACK_TOTAL_HITS_DISABLED), true);
+    }
+
+    /**
+     * Test for DESC order search_after query with track_total_hits=true.
+     * Min = 0L, Max = 9L, search_after = -1L
+     * With above min/max and search_after, it should not match, but since
+     * track_total_hits = true,
+     * Expected result is canMatch = true
+     */
+    public void testCanMatchSearchAfterDescLessThanMinWithTrackTotalhits() throws IOException {
+        FieldDoc searchAfter = new FieldDoc(0, 0, new Long[] { -1L });
+        MinAndMax<?> minMax = new MinAndMax<Long>(0L, 9L);
+        FieldSortBuilder primarySort = new FieldSortBuilder("test");
+        primarySort.order(SortOrder.DESC);
+        assertEquals(SearchService.canMatchSearchAfter(searchAfter, minMax, primarySort, 1000), true);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/search/SearchSortValuesAndFormatsTests.java b/server/src/test/java/org/opensearch/search/SearchSortValuesAndFormatsTests.java
index bc6648d693d1d..3149ab0e2905f 100644
--- a/server/src/test/java/org/opensearch/search/SearchSortValuesAndFormatsTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchSortValuesAndFormatsTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.search;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/search/SearchSortValuesTests.java b/server/src/test/java/org/opensearch/search/SearchSortValuesTests.java
index c5471d4b9063c..2f73659c449d4 100644
--- a/server/src/test/java/org/opensearch/search/SearchSortValuesTests.java
+++ b/server/src/test/java/org/opensearch/search/SearchSortValuesTests.java
@@ -33,14 +33,14 @@
 package org.opensearch.search;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.lucene.LuceneTests;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -49,13 +49,13 @@
 
 public class SearchSortValuesTests extends AbstractSerializingTestCase<SearchSortValues> {
 
-    public static SearchSortValues createTestItem(XContentType xContentType, boolean transportSerialization) {
+    public static SearchSortValues createTestItem(final MediaType mediaType, boolean transportSerialization) {
         int size = randomIntBetween(1, 20);
         Object[] values = new Object[size];
         if (transportSerialization) {
             DocValueFormat[] sortValueFormats = new DocValueFormat[size];
             for (int i = 0; i < size; i++) {
-                Object sortValue = randomSortValue(xContentType, transportSerialization);
+                Object sortValue = randomSortValue(mediaType, transportSerialization);
                 values[i] = sortValue;
                 // make sure that for BytesRef, we provide a specific doc value format that overrides format(BytesRef)
                 sortValueFormats[i] = sortValue instanceof BytesRef ? DocValueFormat.RAW : randomDocValueFormat();
@@ -64,7 +64,7 @@ public static SearchSortValues createTestItem(XContentType xContentType, boolean
         } else {
             // xcontent serialization doesn't write/parse the raw sort values, only the formatted ones
             for (int i = 0; i < size; i++) {
-                Object sortValue = randomSortValue(xContentType, transportSerialization);
+                Object sortValue = randomSortValue(mediaType, transportSerialization);
                 // make sure that BytesRef are not provided as formatted values
                 sortValue = sortValue instanceof BytesRef ? DocValueFormat.RAW.format((BytesRef) sortValue) : sortValue;
                 values[i] = sortValue;
@@ -73,10 +73,10 @@ public static SearchSortValues createTestItem(XContentType xContentType, boolean
         }
     }
 
-    private static Object randomSortValue(XContentType xContentType, boolean transportSerialization) {
+    private static Object randomSortValue(final MediaType mediaType, boolean transportSerialization) {
         Object randomSortValue = LuceneTests.randomSortValue();
         // to simplify things, we directly serialize what we expect we would parse back when testing xcontent serialization
-        return transportSerialization ? randomSortValue : RandomObjects.getExpectedParsedValue(xContentType, randomSortValue);
+        return transportSerialization ? randomSortValue : RandomObjects.getExpectedParsedValue(mediaType, randomSortValue);
     }
 
     private static DocValueFormat randomDocValueFormat() {
@@ -103,8 +103,8 @@ protected SearchSortValues doParseInstance(XContentParser parser) throws IOExcep
     }
 
     @Override
-    protected SearchSortValues createXContextTestInstance(XContentType xContentType) {
-        return createTestItem(xContentType, false);
+    protected SearchSortValues createXContextTestInstance(final MediaType mediaType) {
+        return createTestItem(mediaType, false);
     }
 
     @Override
@@ -129,7 +129,7 @@ public void testToXContent() throws IOException {
             builder.startObject();
             sortValues.toXContent(builder, ToXContent.EMPTY_PARAMS);
             builder.endObject();
-            assertEquals("{\"sort\":[1,\"foo\",3.0]}", Strings.toString(builder));
+            assertEquals("{\"sort\":[1,\"foo\",3.0]}", builder.toString());
         }
         {
             SearchSortValues sortValues = new SearchSortValues(new Object[0]);
@@ -137,7 +137,7 @@ public void testToXContent() throws IOException {
             builder.startObject();
             sortValues.toXContent(builder, ToXContent.EMPTY_PARAMS);
             builder.endObject();
-            assertEquals("{}", Strings.toString(builder));
+            assertEquals("{}", builder.toString());
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorManagerTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorManagerTests.java
new file mode 100644
index 0000000000000..47ce0f120334b
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorManagerTests.java
@@ -0,0 +1,134 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.opensearch.search.aggregations.bucket.global.GlobalAggregator;
+import org.opensearch.search.profile.query.CollectorResult;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.mockito.Mockito.mock;
+
+public class AggregationCollectorManagerTests extends AggregationSetupTests {
+
+    public void testNonGlobalCollectorManagers() throws Exception {
+        final AggregatorFactories aggregatorFactories = getAggregationFactories(multipleNonGlobalAggs);
+        final SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        int expectedAggCount = 2;
+        final AggregationCollectorManager testAggCollectorManager = new NonGlobalAggCollectorManagerWithSingleCollector(context);
+        Collector aggCollector = testAggCollectorManager.newCollector();
+        assertTrue(aggCollector instanceof MultiBucketCollector);
+        assertEquals(expectedAggCount, ((MultiBucketCollector) aggCollector).getCollectors().length);
+        testCollectorManagerCommon(testAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION, testAggCollectorManager.getCollectorReason());
+
+        // test NonGlobalCollectorManager which will be used in concurrent segment search case
+        final NonGlobalAggCollectorManager testNonGlobalAggCollectorManager = new NonGlobalAggCollectorManager(context);
+        testCollectorManagerCommon(testNonGlobalAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION, testAggCollectorManager.getCollectorReason());
+    }
+
+    public void testGlobalCollectorManagers() throws Exception {
+        final AggregatorFactories aggregatorFactories = getAggregationFactories(globalAgg);
+        final SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        final AggregationCollectorManager testAggCollectorManager = new GlobalAggCollectorManagerWithSingleCollector(context);
+        testCollectorManagerCommon(testAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION_GLOBAL, testAggCollectorManager.getCollectorReason());
+        Collector aggCollector = testAggCollectorManager.newCollector();
+        assertTrue(aggCollector instanceof BucketCollector);
+
+        // test GlobalAggCollectorManager which will be used in concurrent segment search case
+        final GlobalAggCollectorManager testGlobalAggCollectorManager = new GlobalAggCollectorManager(context);
+        testCollectorManagerCommon(testGlobalAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION_GLOBAL, testAggCollectorManager.getCollectorReason());
+    }
+
+    public void testAggCollectorManagersWithBothGlobalNonGlobalAggregators() throws Exception {
+        final AggregatorFactories aggregatorFactories = getAggregationFactories(globalNonGlobalAggs);
+        final SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        final AggregationCollectorManager testAggCollectorManager = new NonGlobalAggCollectorManagerWithSingleCollector(context);
+        Collector aggCollector = testAggCollectorManager.newCollector();
+        assertTrue(aggCollector instanceof BucketCollector);
+        assertFalse(aggCollector instanceof GlobalAggregator);
+
+        final AggregationCollectorManager testGlobalAggCollectorManager = new GlobalAggCollectorManagerWithSingleCollector(context);
+        Collector globalAggCollector = testGlobalAggCollectorManager.newCollector();
+        assertTrue(globalAggCollector instanceof BucketCollector);
+        assertTrue(globalAggCollector instanceof GlobalAggregator);
+
+        testCollectorManagerCommon(testAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION, testAggCollectorManager.getCollectorReason());
+        testCollectorManagerCommon(testGlobalAggCollectorManager);
+        assertEquals(CollectorResult.REASON_AGGREGATION_GLOBAL, testGlobalAggCollectorManager.getCollectorReason());
+    }
+
+    public void testAssertionWhenCollectorManagerCreatesNoOPCollector() throws Exception {
+        AggregatorFactories aggregatorFactories = getAggregationFactories(globalAgg);
+        SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        expectThrows(AssertionError.class, () -> new NonGlobalAggCollectorManagerWithSingleCollector(context));
+        expectThrows(AssertionError.class, () -> new NonGlobalAggCollectorManager(context));
+
+        aggregatorFactories = getAggregationFactories(multipleNonGlobalAggs);
+        contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        expectThrows(AssertionError.class, () -> new GlobalAggCollectorManagerWithSingleCollector(context));
+        expectThrows(AssertionError.class, () -> new GlobalAggCollectorManager(context));
+    }
+
+    public void testAssertionInSingleCollectorCMReduce() throws Exception {
+        AggregatorFactories aggregatorFactories = getAggregationFactories(globalNonGlobalAggs);
+        SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        List<Collector> collectorsList = new ArrayList<>();
+        collectorsList.add(mock(Collector.class));
+        context.aggregations(contextAggregations);
+        AggregationCollectorManager globalCM = new GlobalAggCollectorManagerWithSingleCollector(context);
+        AggregationCollectorManager nonGlobalCM = new NonGlobalAggCollectorManagerWithSingleCollector(context);
+        expectThrows(AssertionError.class, () -> globalCM.reduce(collectorsList));
+        expectThrows(AssertionError.class, () -> nonGlobalCM.reduce(collectorsList));
+    }
+
+    private void testCollectorManagerCommon(AggregationCollectorManager collectorManager) throws Exception {
+        final Collector expectedCollector = collectorManager.newCollector();
+        for (int i = 0; i < randomIntBetween(2, 5); ++i) {
+            final Collector newCollector = collectorManager.newCollector();
+            if (collectorManager instanceof GlobalAggCollectorManagerWithSingleCollector
+                || collectorManager instanceof NonGlobalAggCollectorManagerWithSingleCollector) {
+                // calling the newCollector multiple times should return the same instance each time
+                assertSame(expectedCollector, newCollector);
+            } else if (collectorManager instanceof GlobalAggCollectorManager || collectorManager instanceof NonGlobalAggCollectorManager) {
+                // calling the newCollector multiple times should not return the same instance each time
+                assertNotSame(expectedCollector, newCollector);
+            }
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorTests.java
index c48e99e16db2e..a39a261f01ccc 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregationCollectorTests.java
@@ -32,24 +32,18 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.IndexService;
-import org.opensearch.search.internal.SearchContext;
-import org.opensearch.test.OpenSearchSingleNodeTestCase;
+import org.opensearch.search.aggregations.bucket.global.GlobalAggregator;
+import org.opensearch.search.aggregations.bucket.terms.NumericTermsAggregator;
 
 import java.io.IOException;
+import java.util.List;
 
-public class AggregationCollectorTests extends OpenSearchSingleNodeTestCase {
+public class AggregationCollectorTests extends AggregationSetupTests {
 
     public void testNeedsScores() throws Exception {
-        IndexService index = createIndex("idx");
-        client().prepareIndex("idx").setId("1").setSource("f", 5).execute().get();
-        client().admin().indices().prepareRefresh("idx").get();
-
         // simple field aggregation, no scores needed
         String fieldAgg = "{ \"my_terms\": {\"terms\": {\"field\": \"f\"}}}";
-        assertFalse(needsScores(index, fieldAgg));
+        assertFalse(needsScores(fieldAgg));
 
         // agg on a script => scores are needed
         // TODO: can we use a mock script service here?
@@ -61,23 +55,50 @@ public void testNeedsScores() throws Exception {
 
         // make sure the information is propagated to sub aggregations
         String subFieldAgg = "{ \"my_outer_terms\": { \"terms\": { \"field\": \"f\" }, \"aggs\": " + fieldAgg + "}}";
-        assertFalse(needsScores(index, subFieldAgg));
+        assertFalse(needsScores(subFieldAgg));
 
         // top_hits is a particular example of an aggregation that needs scores
         String topHitsAgg = "{ \"my_hits\": {\"top_hits\": {}}}";
-        assertTrue(needsScores(index, topHitsAgg));
+        assertTrue(needsScores(topHitsAgg));
+    }
+
+    public void testNonGlobalTopLevelAggregators() throws Exception {
+        // simple field aggregation
+        String fieldAgg = "{ \"my_terms\": {\"terms\": {\"field\": \"f\"}}}";
+        final List<Aggregator> aggregators = createNonGlobalAggregators(fieldAgg);
+        final List<Aggregator> topLevelAggregators = createTopLevelAggregators(fieldAgg);
+        assertEquals(topLevelAggregators.size(), aggregators.size());
+        assertEquals(topLevelAggregators.get(0).name(), aggregators.get(0).name());
+        assertTrue(aggregators.get(0) instanceof NumericTermsAggregator);
+    }
+
+    public void testGlobalAggregators() throws Exception {
+        // global aggregation
+        final List<Aggregator> aggregators = createGlobalAggregators(globalAgg);
+        final List<Aggregator> topLevelAggregators = createTopLevelAggregators(globalAgg);
+        assertEquals(topLevelAggregators.size(), aggregators.size());
+        assertEquals(topLevelAggregators.get(0).name(), aggregators.get(0).name());
+        assertTrue(aggregators.get(0) instanceof GlobalAggregator);
     }
 
-    private boolean needsScores(IndexService index, String agg) throws IOException {
-        try (XContentParser aggParser = createParser(JsonXContent.jsonXContent, agg)) {
-            aggParser.nextToken();
-            SearchContext context = createSearchContext(index);
-            final AggregatorFactories factories = AggregatorFactories.parseAggregators(aggParser)
-                .build(context.getQueryShardContext(), null);
-            final Aggregator[] aggregators = factories.createTopLevelAggregators(context);
-            assertEquals(1, aggregators.length);
-            return aggregators[0].scoreMode().needsScores();
-        }
+    private boolean needsScores(String agg) throws IOException {
+        final List<Aggregator> aggregators = createTopLevelAggregators(agg);
+        assertEquals(1, aggregators.size());
+        return aggregators.get(0).scoreMode().needsScores();
     }
 
+    private List<Aggregator> createTopLevelAggregators(String agg) throws IOException {
+        final AggregatorFactories factories = getAggregationFactories(agg);
+        return factories.createTopLevelAggregators(context);
+    }
+
+    private List<Aggregator> createNonGlobalAggregators(String agg) throws IOException {
+        final AggregatorFactories factories = getAggregationFactories(agg);
+        return factories.createTopLevelNonGlobalAggregators(context);
+    }
+
+    private List<Aggregator> createGlobalAggregators(String agg) throws IOException {
+        final AggregatorFactories factories = getAggregationFactories(agg);
+        return factories.createTopLevelGlobalAggregators(context);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregationProcessorTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregationProcessorTests.java
new file mode 100644
index 0000000000000..a4bd815350bc2
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregationProcessorTests.java
@@ -0,0 +1,195 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.Query;
+import org.opensearch.search.aggregations.bucket.global.GlobalAggregator;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.profile.query.CollectorResult;
+import org.opensearch.search.query.ReduceableSearchResult;
+import org.opensearch.test.TestSearchContext;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import org.mockito.ArgumentMatchers;
+
+import static org.mockito.ArgumentMatchers.nullable;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class AggregationProcessorTests extends AggregationSetupTests {
+    private final AggregationProcessor testAggregationProcessor = new ConcurrentAggregationProcessor();
+
+    public void testPreProcessWithNoAggregations() {
+        testAggregationProcessor.preProcess(context);
+        assertTrue(context.queryCollectorManagers().isEmpty());
+    }
+
+    public void testPreProcessWithOnlyGlobalAggregator() throws Exception {
+        testPreProcessCommon(globalAgg, 1, 0);
+    }
+
+    public void testPreProcessWithGlobalAndNonGlobalAggregators() throws Exception {
+        testPreProcessCommon(globalNonGlobalAggs, 1, 1);
+    }
+
+    public void testPreProcessWithOnlyNonGlobalAggregators() throws Exception {
+        testPreProcessCommon(multipleNonGlobalAggs, 0, 2);
+    }
+
+    public void testPostProcessWithNonGlobalAggregatorsAndSingleSlice() throws Exception {
+        testPostProcessCommon(multipleNonGlobalAggs, 1, 0, 2, false);
+    }
+
+    public void testPostProcessWithNonGlobalAggregatorsAndMultipleSlices() throws Exception {
+        testPostProcessCommon(multipleNonGlobalAggs, randomIntBetween(2, 5), 0, 2, false);
+    }
+
+    public void testPostProcessGlobalAndNonGlobalAggregators() throws Exception {
+        testPostProcessCommon(globalNonGlobalAggs, randomIntBetween(2, 5), 1, 1, false);
+    }
+
+    public void testPostProcessGlobalAndNonGlobalAggregatorsWithProfilers() throws Exception {
+        testPostProcessCommon(globalNonGlobalAggs, randomIntBetween(2, 5), 1, 1, true);
+    }
+
+    private void testPreProcessCommon(String agg, int expectedGlobalAggs, int expectedNonGlobalAggs) throws Exception {
+        testPreProcessCommon(agg, expectedGlobalAggs, expectedNonGlobalAggs, new ArrayList<>(), new ArrayList<>());
+    }
+
+    private void testPreProcessCommon(
+        String agg,
+        int expectedGlobalAggs,
+        int expectedNonGlobalAggs,
+        Collection<Collector> createdNonGlobalCollectors,
+        Collection<Collector> createdGlobalCollectors
+    ) throws Exception {
+        final AggregatorFactories aggregatorFactories = getAggregationFactories(agg);
+        final SearchContextAggregations contextAggregations = new SearchContextAggregations(
+            aggregatorFactories,
+            mock(MultiBucketConsumerService.MultiBucketConsumer.class)
+        );
+        context.aggregations(contextAggregations);
+        testAggregationProcessor.preProcess(context);
+        CollectorManager<?, ?> globalCollectorManager = null;
+        CollectorManager<?, ?> nonGlobalCollectorManager = null;
+        if (expectedNonGlobalAggs == 0 && expectedGlobalAggs == 0) {
+            assertTrue(context.queryCollectorManagers().isEmpty());
+            return;
+        } else if (expectedGlobalAggs > 0 && expectedNonGlobalAggs > 0) {
+            assertTrue(context.queryCollectorManagers().containsKey(NonGlobalAggCollectorManager.class));
+            assertTrue(context.queryCollectorManagers().containsKey(GlobalAggCollectorManager.class));
+            globalCollectorManager = context.queryCollectorManagers().get(GlobalAggCollectorManager.class);
+            nonGlobalCollectorManager = context.queryCollectorManagers().get(NonGlobalAggCollectorManager.class);
+        } else if (expectedGlobalAggs == 0) {
+            assertTrue(context.queryCollectorManagers().containsKey(NonGlobalAggCollectorManager.class));
+            assertFalse(context.queryCollectorManagers().containsKey(GlobalAggCollectorManager.class));
+            nonGlobalCollectorManager = context.queryCollectorManagers().get(NonGlobalAggCollectorManager.class);
+        } else {
+            assertTrue(context.queryCollectorManagers().containsKey(GlobalAggCollectorManager.class));
+            assertFalse(context.queryCollectorManagers().containsKey(NonGlobalAggCollectorManager.class));
+            globalCollectorManager = context.queryCollectorManagers().get(GlobalAggCollectorManager.class);
+        }
+
+        Collector aggCollector;
+        if (expectedGlobalAggs == 1) {
+            aggCollector = globalCollectorManager.newCollector();
+            createdGlobalCollectors.add(aggCollector);
+            assertTrue(aggCollector instanceof BucketCollector);
+            assertTrue(aggCollector instanceof GlobalAggregator);
+        } else if (expectedGlobalAggs > 1) {
+            aggCollector = globalCollectorManager.newCollector();
+            createdGlobalCollectors.add(aggCollector);
+            assertTrue(aggCollector instanceof MultiBucketCollector);
+            for (Collector currentCollector : ((MultiBucketCollector) aggCollector).getCollectors()) {
+                assertTrue(currentCollector instanceof GlobalAggregator);
+            }
+        }
+
+        if (expectedNonGlobalAggs == 1) {
+            aggCollector = nonGlobalCollectorManager.newCollector();
+            createdNonGlobalCollectors.add(aggCollector);
+            assertTrue(aggCollector instanceof BucketCollector);
+            assertFalse(aggCollector instanceof GlobalAggregator);
+        } else if (expectedNonGlobalAggs > 1) {
+            aggCollector = nonGlobalCollectorManager.newCollector();
+            createdNonGlobalCollectors.add(aggCollector);
+            assertTrue(aggCollector instanceof MultiBucketCollector);
+            for (Collector currentCollector : ((MultiBucketCollector) aggCollector).getCollectors()) {
+                assertFalse(currentCollector instanceof GlobalAggregator);
+            }
+        }
+    }
+
+    private void testPostProcessCommon(
+        String aggs,
+        int numSlices,
+        int expectedGlobalAggs,
+        int expectedNonGlobalAggsPerSlice,
+        boolean withProfilers
+    ) throws Exception {
+        final Collection<Collector> nonGlobalCollectors = new ArrayList<>();
+        final Collection<Collector> globalCollectors = new ArrayList<>();
+        testPreProcessCommon(aggs, expectedGlobalAggs, expectedNonGlobalAggsPerSlice, nonGlobalCollectors, globalCollectors);
+        // newCollector is initialized once in the collector manager constructor
+        for (int i = 1; i < numSlices; ++i) {
+            if (expectedNonGlobalAggsPerSlice > 0) {
+                nonGlobalCollectors.add(context.queryCollectorManagers().get(NonGlobalAggCollectorManager.class).newCollector());
+            }
+            if (expectedGlobalAggs > 0) {
+                globalCollectors.add(context.queryCollectorManagers().get(GlobalAggCollectorManager.class).newCollector());
+            }
+        }
+        final ContextIndexSearcher testSearcher = mock(ContextIndexSearcher.class);
+        final IndexSearcher.LeafSlice[] slicesToReturn = new IndexSearcher.LeafSlice[numSlices];
+        when(testSearcher.getSlices()).thenReturn(slicesToReturn);
+        ((TestSearchContext) context).setSearcher(testSearcher);
+        AggregationCollectorManager collectorManager;
+        if (expectedNonGlobalAggsPerSlice > 0) {
+            collectorManager = (AggregationCollectorManager) context.queryCollectorManagers().get(NonGlobalAggCollectorManager.class);
+            collectorManager.reduce(nonGlobalCollectors).reduce(context.queryResult());
+        }
+        if (expectedGlobalAggs > 0) {
+            collectorManager = (AggregationCollectorManager) context.queryCollectorManagers().get(GlobalAggCollectorManager.class);
+            ReduceableSearchResult result = collectorManager.reduce(globalCollectors);
+            when(testSearcher.search(nullable(Query.class), ArgumentMatchers.<CollectorManager<?, ReduceableSearchResult>>any()))
+                .thenReturn(result);
+        }
+        assertTrue(context.queryResult().hasAggs());
+        if (withProfilers) {
+            ((TestSearchContext) context).withProfilers();
+        }
+        testAggregationProcessor.postProcess(context);
+        assertTrue(context.queryResult().hasAggs());
+        // for global aggs verify that search.search is called with CollectionManager
+        if (expectedGlobalAggs > 0) {
+            verify(testSearcher, times(1)).search(nullable(Query.class), ArgumentMatchers.<CollectorManager<?, ?>>any());
+            if (withProfilers) {
+                // First profiler is from withProfilers() call, second one is from postProcess() call
+                assertEquals(2, context.getProfilers().getQueryProfilers().size());
+                assertEquals(
+                    CollectorResult.REASON_AGGREGATION_GLOBAL,
+                    context.getProfilers().getQueryProfilers().get(1).getCollector().getReason()
+                );
+            }
+        }
+        // after shard level reduce it should have only 1 InternalAggregation instance for each agg in request and internal aggregation
+        // will be equal to sum of expected global and nonglobal aggs
+        assertEquals(expectedNonGlobalAggsPerSlice + expectedGlobalAggs, context.queryResult().aggregations().expand().aggregations.size());
+        assertNotNull(context.queryResult().aggregations().expand().getPipelineTreeForBwcSerialization());
+        assertNull(context.aggregations());
+        assertTrue(context.queryCollectorManagers().isEmpty());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregationSetupTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregationSetupTests.java
new file mode 100644
index 0000000000000..7adad946ae658
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregationSetupTests.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.opensearch.action.OriginalIndices;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.IndexService;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.internal.ShardSearchRequest;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+import org.opensearch.test.TestSearchContext;
+
+import java.io.IOException;
+
+public class AggregationSetupTests extends OpenSearchSingleNodeTestCase {
+    protected IndexService index;
+
+    protected SearchContext context;
+
+    protected final String globalNonGlobalAggs = "{ \"my_terms\": {\"terms\": {\"field\": \"f\"}}, "
+        + "\"all_products\": {\"global\": {}, \"aggs\": {\"avg_price\": {\"avg\": { \"field\": \"f\"}}}}}";
+
+    protected final String multipleNonGlobalAggs = "{ \"my_terms\": {\"terms\": {\"field\": \"f\"}}, "
+        + "\"avg_price\": {\"avg\": { \"field\": \"f\"}}}";
+
+    protected final String globalAgg = "{ \"all_products\": {\"global\": {}, \"aggs\": {\"avg_price\": {\"avg\": { \"field\": \"f\"}}}}}";
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        index = createIndex("idx");
+        client().prepareIndex("idx").setId("1").setSource("f", 5).execute().get();
+        client().admin().indices().prepareRefresh("idx").get();
+        context = createSearchContext(index);
+        final AggregationBuilder dummyAggBuilder = AggregationBuilders.avg(randomAlphaOfLengthBetween(5, 20)).field("foo");
+        final SearchRequest searchRequest = new SearchRequest(
+            new String[] { index.index().getName() },
+            new SearchSourceBuilder().aggregation(dummyAggBuilder)
+        ).allowPartialSearchResults(false);
+        ((TestSearchContext) context).setShardSearchRequest(
+            new ShardSearchRequest(
+                OriginalIndices.NONE,
+                searchRequest,
+                new ShardId(index.index(), 0),
+                1,
+                null,
+                1.0f,
+                0,
+                null,
+                Strings.EMPTY_ARRAY
+            )
+        );
+        ((TestSearchContext) context).setConcurrentSegmentSearchEnabled(true);
+    }
+
+    protected AggregatorFactories getAggregationFactories(String agg) throws IOException {
+        try (XContentParser aggParser = createParser(JsonXContent.jsonXContent, agg)) {
+            aggParser.nextToken();
+            return AggregatorFactories.parseAggregators(aggParser).build(context.getQueryShardContext(), null);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregationsTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregationsTests.java
index fe029d22a45b2..73e6d3814fa8d 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregationsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregationsTests.java
@@ -32,24 +32,23 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.search.aggregations.Aggregation.CommonFields;
 import org.opensearch.search.aggregations.bucket.adjacency.InternalAdjacencyMatrixTests;
 import org.opensearch.search.aggregations.bucket.composite.InternalCompositeTests;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilterTests;
 import org.opensearch.search.aggregations.bucket.filter.InternalFiltersTests;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridTests;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridTests;
 import org.opensearch.search.aggregations.bucket.global.InternalGlobalTests;
 import org.opensearch.search.aggregations.bucket.histogram.InternalAutoDateHistogramTests;
 import org.opensearch.search.aggregations.bucket.histogram.InternalDateHistogramTests;
@@ -64,46 +63,46 @@
 import org.opensearch.search.aggregations.bucket.range.InternalRangeTests;
 import org.opensearch.search.aggregations.bucket.sampler.InternalSamplerTests;
 import org.opensearch.search.aggregations.bucket.terms.DoubleTermsTests;
+import org.opensearch.search.aggregations.bucket.terms.InternalMultiTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.LongRareTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.LongTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.SignificantLongTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.SignificantStringTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.StringRareTermsTests;
 import org.opensearch.search.aggregations.bucket.terms.StringTermsTests;
+import org.opensearch.search.aggregations.bucket.terms.UnsignedLongTermsTests;
+import org.opensearch.search.aggregations.metrics.InternalAvgTests;
+import org.opensearch.search.aggregations.metrics.InternalCardinalityTests;
 import org.opensearch.search.aggregations.metrics.InternalExtendedStatsTests;
+import org.opensearch.search.aggregations.metrics.InternalGeoCentroidTests;
+import org.opensearch.search.aggregations.metrics.InternalHDRPercentilesRanksTests;
+import org.opensearch.search.aggregations.metrics.InternalHDRPercentilesTests;
 import org.opensearch.search.aggregations.metrics.InternalMaxTests;
 import org.opensearch.search.aggregations.metrics.InternalMedianAbsoluteDeviationTests;
 import org.opensearch.search.aggregations.metrics.InternalMinTests;
+import org.opensearch.search.aggregations.metrics.InternalScriptedMetricTests;
 import org.opensearch.search.aggregations.metrics.InternalStatsBucketTests;
 import org.opensearch.search.aggregations.metrics.InternalStatsTests;
 import org.opensearch.search.aggregations.metrics.InternalSumTests;
-import org.opensearch.search.aggregations.metrics.InternalAvgTests;
-import org.opensearch.search.aggregations.metrics.InternalCardinalityTests;
-import org.opensearch.search.aggregations.metrics.InternalGeoBoundsTests;
-import org.opensearch.search.aggregations.metrics.InternalGeoCentroidTests;
-import org.opensearch.search.aggregations.metrics.InternalHDRPercentilesRanksTests;
-import org.opensearch.search.aggregations.metrics.InternalHDRPercentilesTests;
 import org.opensearch.search.aggregations.metrics.InternalTDigestPercentilesRanksTests;
 import org.opensearch.search.aggregations.metrics.InternalTDigestPercentilesTests;
-import org.opensearch.search.aggregations.metrics.InternalScriptedMetricTests;
 import org.opensearch.search.aggregations.metrics.InternalTopHitsTests;
 import org.opensearch.search.aggregations.metrics.InternalValueCountTests;
 import org.opensearch.search.aggregations.metrics.InternalWeightedAvgTests;
-import org.opensearch.search.aggregations.pipeline.InternalSimpleValueTests;
 import org.opensearch.search.aggregations.pipeline.InternalBucketMetricValueTests;
-import org.opensearch.search.aggregations.pipeline.InternalPercentilesBucketTests;
-import org.opensearch.search.aggregations.pipeline.InternalExtendedStatsBucketTests;
 import org.opensearch.search.aggregations.pipeline.InternalDerivativeTests;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.search.aggregations.pipeline.InternalExtendedStatsBucketTests;
+import org.opensearch.search.aggregations.pipeline.InternalPercentilesBucketTests;
+import org.opensearch.search.aggregations.pipeline.InternalSimpleValueTests;
 import org.opensearch.test.InternalAggregationTestCase;
 import org.opensearch.test.InternalMultiBucketAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 import org.junit.After;
 import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.function.Predicate;
@@ -118,62 +117,57 @@
  *
  */
 public class AggregationsTests extends OpenSearchTestCase {
-    private static final List<InternalAggregationTestCase<?>> aggsTests = getAggsTests();
-
-    private static List<InternalAggregationTestCase<?>> getAggsTests() {
-        List<InternalAggregationTestCase<?>> aggsTests = new ArrayList<>();
-        aggsTests.add(new InternalCardinalityTests());
-        aggsTests.add(new InternalTDigestPercentilesTests());
-        aggsTests.add(new InternalTDigestPercentilesRanksTests());
-        aggsTests.add(new InternalHDRPercentilesTests());
-        aggsTests.add(new InternalHDRPercentilesRanksTests());
-        aggsTests.add(new InternalPercentilesBucketTests());
-        aggsTests.add(new InternalMinTests());
-        aggsTests.add(new InternalMaxTests());
-        aggsTests.add(new InternalAvgTests());
-        aggsTests.add(new InternalWeightedAvgTests());
-        aggsTests.add(new InternalSumTests());
-        aggsTests.add(new InternalValueCountTests());
-        aggsTests.add(new InternalSimpleValueTests());
-        aggsTests.add(new InternalDerivativeTests());
-        aggsTests.add(new InternalBucketMetricValueTests());
-        aggsTests.add(new InternalStatsTests());
-        aggsTests.add(new InternalStatsBucketTests());
-        aggsTests.add(new InternalExtendedStatsTests());
-        aggsTests.add(new InternalExtendedStatsBucketTests());
-        aggsTests.add(new InternalGeoBoundsTests());
-        aggsTests.add(new InternalGeoCentroidTests());
-        aggsTests.add(new InternalHistogramTests());
-        aggsTests.add(new InternalDateHistogramTests());
-        aggsTests.add(new InternalAutoDateHistogramTests());
-        aggsTests.add(new InternalVariableWidthHistogramTests());
-        aggsTests.add(new LongTermsTests());
-        aggsTests.add(new DoubleTermsTests());
-        aggsTests.add(new StringTermsTests());
-        aggsTests.add(new LongRareTermsTests());
-        aggsTests.add(new StringRareTermsTests());
-        aggsTests.add(new InternalMissingTests());
-        aggsTests.add(new InternalNestedTests());
-        aggsTests.add(new InternalReverseNestedTests());
-        aggsTests.add(new InternalGlobalTests());
-        aggsTests.add(new InternalFilterTests());
-        aggsTests.add(new InternalSamplerTests());
-        aggsTests.add(new GeoHashGridTests());
-        aggsTests.add(new GeoTileGridTests());
-        aggsTests.add(new InternalRangeTests());
-        aggsTests.add(new InternalDateRangeTests());
-        aggsTests.add(new InternalGeoDistanceTests());
-        aggsTests.add(new InternalFiltersTests());
-        aggsTests.add(new InternalAdjacencyMatrixTests());
-        aggsTests.add(new SignificantLongTermsTests());
-        aggsTests.add(new SignificantStringTermsTests());
-        aggsTests.add(new InternalScriptedMetricTests());
-        aggsTests.add(new InternalBinaryRangeTests());
-        aggsTests.add(new InternalTopHitsTests());
-        aggsTests.add(new InternalCompositeTests());
-        aggsTests.add(new InternalMedianAbsoluteDeviationTests());
-        return Collections.unmodifiableList(aggsTests);
-    }
+    private static final List<InternalAggregationTestCase<?>> aggsTests = List.of(
+        new InternalCardinalityTests(),
+        new InternalTDigestPercentilesTests(),
+        new InternalTDigestPercentilesRanksTests(),
+        new InternalHDRPercentilesTests(),
+        new InternalHDRPercentilesRanksTests(),
+        new InternalPercentilesBucketTests(),
+        new InternalMinTests(),
+        new InternalMaxTests(),
+        new InternalAvgTests(),
+        new InternalWeightedAvgTests(),
+        new InternalSumTests(),
+        new InternalValueCountTests(),
+        new InternalSimpleValueTests(),
+        new InternalDerivativeTests(),
+        new InternalBucketMetricValueTests(),
+        new InternalStatsTests(),
+        new InternalStatsBucketTests(),
+        new InternalExtendedStatsTests(),
+        new InternalExtendedStatsBucketTests(),
+        new InternalGeoCentroidTests(),
+        new InternalHistogramTests(),
+        new InternalDateHistogramTests(),
+        new InternalAutoDateHistogramTests(),
+        new InternalVariableWidthHistogramTests(),
+        new UnsignedLongTermsTests(),
+        new LongTermsTests(),
+        new DoubleTermsTests(),
+        new StringTermsTests(),
+        new LongRareTermsTests(),
+        new StringRareTermsTests(),
+        new InternalMissingTests(),
+        new InternalNestedTests(),
+        new InternalReverseNestedTests(),
+        new InternalGlobalTests(),
+        new InternalFilterTests(),
+        new InternalSamplerTests(),
+        new InternalRangeTests(),
+        new InternalDateRangeTests(),
+        new InternalGeoDistanceTests(),
+        new InternalFiltersTests(),
+        new InternalAdjacencyMatrixTests(),
+        new SignificantLongTermsTests(),
+        new SignificantStringTermsTests(),
+        new InternalScriptedMetricTests(),
+        new InternalBinaryRangeTests(),
+        new InternalTopHitsTests(),
+        new InternalCompositeTests(),
+        new InternalMedianAbsoluteDeviationTests(),
+        new InternalMultiTermsTests()
+    );
 
     @Override
     protected NamedXContentRegistry xContentRegistry() {
@@ -218,7 +212,7 @@ public void testFromXContentWithRandomFields() throws IOException {
     /**
      * Test that parsing works for a randomly created Aggregations object with a
      * randomized aggregation tree. The test randomly chooses an
-     * {@link XContentType}, randomizes the order of the {@link XContent} fields
+     * {@link MediaType}, randomizes the order of the {@link XContent} fields
      * and randomly sets the `humanReadable` flag when rendering the
      * {@link XContent}.
      *
@@ -228,10 +222,10 @@ public void testFromXContentWithRandomFields() throws IOException {
      *            responses
      */
     private void parseAndAssert(boolean addRandomFields) throws IOException {
-        XContentType xContentType = randomFrom(XContentType.values());
+        MediaType mediaType = randomFrom(XContentType.values());
         final ToXContent.Params params = new ToXContent.MapParams(singletonMap(RestSearchAction.TYPED_KEYS_PARAM, "true"));
-        Aggregations aggregations = createTestInstance();
-        BytesReference originalBytes = toShuffledXContent(aggregations, xContentType, params, randomBoolean());
+        Aggregations aggregations = createTestInstance(1, 0, 3);
+        BytesReference originalBytes = toShuffledXContent(aggregations, mediaType, params, randomBoolean());
         BytesReference mutated;
         if (addRandomFields) {
             /*
@@ -261,18 +255,18 @@ private void parseAndAssert(boolean addRandomFields) throws IOException {
                 || path.endsWith("correlation")
                 || path.contains(CommonFields.VALUE.getPreferredName())
                 || path.endsWith(CommonFields.KEY.getPreferredName())) || path.contains("top_hits");
-            mutated = insertRandomFields(xContentType, originalBytes, excludes, random());
+            mutated = insertRandomFields(mediaType, originalBytes, excludes, random());
         } else {
             mutated = originalBytes;
         }
-        try (XContentParser parser = createParser(xContentType.xContent(), mutated)) {
+        try (XContentParser parser = createParser(mediaType.xContent(), mutated)) {
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
             assertEquals(Aggregations.AGGREGATIONS_FIELD, parser.currentName());
             assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
             Aggregations parsedAggregations = Aggregations.fromXContent(parser);
-            BytesReference parsedBytes = XContentHelper.toXContent(parsedAggregations, xContentType, randomBoolean());
-            OpenSearchAssertions.assertToXContentEquivalent(originalBytes, parsedBytes, xContentType);
+            BytesReference parsedBytes = XContentHelper.toXContent(parsedAggregations, mediaType, randomBoolean());
+            OpenSearchAssertions.assertToXContentEquivalent(originalBytes, parsedBytes, mediaType);
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregatorBaseTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregatorBaseTests.java
index 312ebfcfae5e8..728b7162bf478 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregatorBaseTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregatorBaseTests.java
@@ -38,16 +38,16 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.search.aggregations.support.ValuesSourceConfig;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesBuilderTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesBuilderTests.java
index 184a3150183c7..0e77838a62292 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesBuilderTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable.Reader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.aggregations.AggregatorFactories.Builder;
 import org.opensearch.search.aggregations.pipeline.CumulativeSumPipelineAggregationBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
index 17abfbf489916..c930d27b068f8 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
@@ -31,19 +31,19 @@
 
 package org.opensearch.search.aggregations;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
@@ -239,7 +239,7 @@ public void testInvalidType() throws Exception {
     public void testRewriteAggregation() throws Exception {
         XContentType xContentType = randomFrom(XContentType.values());
         BytesReference bytesReference;
-        try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType)) {
             builder.startObject();
             {
                 builder.startObject("terms");
diff --git a/server/src/test/java/org/opensearch/search/aggregations/InternalAggregationsTests.java b/server/src/test/java/org/opensearch/search/aggregations/InternalAggregationsTests.java
index bb28c0657ac8e..6334323effdeb 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/InternalAggregationsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/InternalAggregationsTests.java
@@ -34,23 +34,24 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.aggregations.bucket.histogram.InternalDateHistogramTests;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringTermsTests;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.opensearch.search.aggregations.pipeline.AvgBucketPipelineAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.InternalSimpleValueTests;
 import org.opensearch.search.aggregations.pipeline.MaxBucketPipelineAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.SiblingPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.SumBucketPipelineAggregationBuilder;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -79,15 +80,14 @@ public void testNonFinalReduceTopLevelPipelineAggs() {
             "name",
             BucketOrder.key(true),
             BucketOrder.key(true),
-            10,
-            1,
             Collections.emptyMap(),
             DocValueFormat.RAW,
             25,
             false,
             10,
             Collections.emptyList(),
-            0
+            0,
+            new TermsAggregator.BucketCountThresholds(1, 0, 10, 25)
         );
         List<InternalAggregations> aggs = singletonList(InternalAggregations.from(Collections.singletonList(terms)));
         InternalAggregations reducedAggs = InternalAggregations.topLevelReduce(aggs, maxBucketReduceContext().forPartialReduction());
@@ -100,15 +100,14 @@ public void testFinalReduceTopLevelPipelineAggs() {
             "name",
             BucketOrder.key(true),
             BucketOrder.key(true),
-            10,
-            1,
             Collections.emptyMap(),
             DocValueFormat.RAW,
             25,
             false,
             10,
             Collections.emptyList(),
-            0
+            0,
+            new TermsAggregator.BucketCountThresholds(1, 0, 10, 25)
         );
 
         InternalAggregations aggs = InternalAggregations.from(Collections.singletonList(terms));
diff --git a/server/src/test/java/org/opensearch/search/aggregations/InternalMultiBucketAggregationTests.java b/server/src/test/java/org/opensearch/search/aggregations/InternalMultiBucketAggregationTests.java
index bc48b546e6d28..b7f4094da9990 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/InternalMultiBucketAggregationTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/InternalMultiBucketAggregationTests.java
@@ -37,6 +37,7 @@
 import org.opensearch.search.aggregations.bucket.terms.InternalTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
+import org.opensearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.opensearch.search.aggregations.metrics.InternalAvg;
 import org.opensearch.search.aggregations.support.AggregationPath;
 import org.opensearch.test.OpenSearchTestCase;
@@ -164,20 +165,18 @@ public void testResolveToSpecificBucket() {
                 DocValueFormat.RAW
             )
         );
-
         InternalTerms termsAgg = new StringTerms(
             "string_terms",
             BucketOrder.count(false),
             BucketOrder.count(false),
-            1,
-            0,
             Collections.emptyMap(),
             DocValueFormat.RAW,
             1,
             false,
             0,
             stringBuckets,
-            0
+            0,
+            new TermsAggregator.BucketCountThresholds(0, 0, 1, 1)
         );
         InternalAggregations internalAggregations = InternalAggregations.from(Collections.singletonList(termsAgg));
         LongTerms.Bucket bucket = new LongTerms.Bucket(19, 1, internalAggregations, false, 0, DocValueFormat.RAW);
@@ -208,15 +207,14 @@ public void testResolveToMissingSpecificBucket() {
             "string_terms",
             BucketOrder.count(false),
             BucketOrder.count(false),
-            1,
-            0,
             Collections.emptyMap(),
             DocValueFormat.RAW,
             1,
             false,
             0,
             stringBuckets,
-            0
+            0,
+            new TermsAggregator.BucketCountThresholds(0, 0, 1, 1)
         );
         InternalAggregations internalAggregations = InternalAggregations.from(Collections.singletonList(termsAgg));
         LongTerms.Bucket bucket = new LongTerms.Bucket(19, 1, internalAggregations, false, 0, DocValueFormat.RAW);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/InternalOrderTests.java b/server/src/test/java/org/opensearch/search/aggregations/InternalOrderTests.java
index b2fe9074e1816..190f35b955853 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/InternalOrderTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/InternalOrderTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.search.aggregations.InternalOrder.CompoundOrder;
 import org.opensearch.test.AbstractSerializingTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/MultiBucketCollectorTests.java b/server/src/test/java/org/opensearch/search/aggregations/MultiBucketCollectorTests.java
index ae1d5c60c231a..8c94a9854ef10 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/MultiBucketCollectorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/MultiBucketCollectorTests.java
@@ -35,13 +35,13 @@
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.CollectionTerminatedException;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/MultiBucketConsumerTests.java b/server/src/test/java/org/opensearch/search/aggregations/MultiBucketConsumerTests.java
new file mode 100644
index 0000000000000..dff7dbc8901a8
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/MultiBucketConsumerTests.java
@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations;
+
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.concurrent.atomic.LongAdder;
+
+import org.mockito.Mockito;
+
+import static org.opensearch.search.aggregations.MultiBucketConsumerService.DEFAULT_MAX_BUCKETS;
+
+public class MultiBucketConsumerTests extends OpenSearchTestCase {
+
+    public void testMultiConsumerAcceptWhenCBTripped() {
+        CircuitBreaker breaker = Mockito.mock(CircuitBreaker.class);
+        MultiBucketConsumerService.MultiBucketConsumer multiBucketConsumer = new MultiBucketConsumerService.MultiBucketConsumer(
+            DEFAULT_MAX_BUCKETS,
+            breaker,
+            new LongAdder(),
+            true,
+            1
+        );
+        // exception is thrown upfront since the circuit breaker has already tripped
+        expectThrows(CircuitBreakingException.class, () -> multiBucketConsumer.accept(0));
+        Mockito.verify(breaker, Mockito.times(0)).addEstimateBytesAndMaybeBreak(0, "allocated_buckets");
+    }
+
+    public void testMultiConsumerAcceptToTripCB() {
+        CircuitBreaker breaker = Mockito.mock(CircuitBreaker.class);
+        LongAdder callCount = new LongAdder();
+        for (int i = 0; i < 1024; i++) {
+            callCount.increment();
+        }
+        MultiBucketConsumerService.MultiBucketConsumer multiBucketConsumer = new MultiBucketConsumerService.MultiBucketConsumer(
+            DEFAULT_MAX_BUCKETS,
+            breaker,
+            callCount,
+            false,
+            2
+        );
+        // circuit breaker check is performed as the value of call count would be 1025 which is still in range
+        Mockito.when(breaker.addEstimateBytesAndMaybeBreak(0, "allocated_buckets")).thenThrow(CircuitBreakingException.class);
+        expectThrows(CircuitBreakingException.class, () -> multiBucketConsumer.accept(0));
+        Mockito.verify(breaker, Mockito.times(1)).addEstimateBytesAndMaybeBreak(0, "allocated_buckets");
+    }
+
+    public void testMultiConsumerAccept() {
+        CircuitBreaker breaker = Mockito.mock(CircuitBreaker.class);
+        LongAdder callCount = new LongAdder();
+        for (int i = 0; i < 1100; i++) {
+            callCount.increment();
+        }
+        MultiBucketConsumerService.MultiBucketConsumer multiBucketConsumer = new MultiBucketConsumerService.MultiBucketConsumer(
+            DEFAULT_MAX_BUCKETS,
+            breaker,
+            callCount,
+            false,
+            1
+        );
+        // no exception is thrown as the call count value is not in the expected range and CB is not checked
+        multiBucketConsumer.accept(0);
+        Mockito.verify(breaker, Mockito.times(0)).addEstimateBytesAndMaybeBreak(0, "allocated_buckets");
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/SubAggCollectionModeTests.java b/server/src/test/java/org/opensearch/search/aggregations/SubAggCollectionModeTests.java
index 2d402f8f9bc7a..9b80f0ba6b6d7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/SubAggCollectionModeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/SubAggCollectionModeTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.search.aggregations;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollectorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollectorTests.java
index cc9628a13c060..692032c4795de 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollectorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/BestBucketsDeferringCollectorTests.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -47,6 +46,7 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.search.aggregations.AggregatorTestCase;
 import org.opensearch.search.aggregations.BucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollector;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/BucketsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/BucketsAggregatorTests.java
index 55f8d11e2d934..6a84b45526b44 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/BucketsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/BucketsAggregatorTests.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.breaker.CircuitBreaker;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.mapper.NumberFieldMapper;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.AggregatorTestCase;
 import org.opensearch.search.aggregations.InternalAggregation;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/DateRangeTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/DateRangeTests.java
index 00b87675da8a0..94d533752a5dc 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/DateRangeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/DateRangeTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.bucket.range.DateRangeAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.range.RangeAggregator.Range;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/DocCountProviderTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/DocCountProviderTests.java
new file mode 100644
index 0000000000000..708d683fe2484
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/DocCountProviderTests.java
@@ -0,0 +1,107 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.aggregations.bucket;
+
+import org.apache.lucene.document.IntPoint;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.index.mapper.DocCountFieldMapper;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.search.aggregations.AggregatorTestCase;
+import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.global.InternalGlobal;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.function.Consumer;
+
+import static java.util.Collections.singleton;
+
+public class DocCountProviderTests extends AggregatorTestCase {
+
+    private static final String DOC_COUNT_FIELD = DocCountFieldMapper.NAME;
+    private static final String NUMBER_FIELD = "number";
+
+    public void testDocsWithDocCount() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(List.of(new NumericDocValuesField(DOC_COUNT_FIELD, 4), new SortedNumericDocValuesField(NUMBER_FIELD, 1)));
+            iw.addDocument(List.of(new NumericDocValuesField(DOC_COUNT_FIELD, 5), new SortedNumericDocValuesField(NUMBER_FIELD, 7)));
+            iw.addDocument(
+                List.of(
+                    // Intentionally omit doc_count field
+                    new SortedNumericDocValuesField(NUMBER_FIELD, 1)
+                )
+            );
+        }, global -> { assertEquals(10, global.getDocCount()); });
+    }
+
+    public void testDocsWithoutDocCount() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(singleton(new SortedNumericDocValuesField(NUMBER_FIELD, 1)));
+            iw.addDocument(singleton(new SortedNumericDocValuesField(NUMBER_FIELD, 7)));
+            iw.addDocument(singleton(new SortedNumericDocValuesField(NUMBER_FIELD, 1)));
+        }, global -> { assertEquals(3, global.getDocCount()); });
+    }
+
+    public void testQueryFiltering() throws IOException {
+        testAggregation(IntPoint.newRangeQuery(NUMBER_FIELD, 4, 5), iw -> {
+            iw.addDocument(List.of(new NumericDocValuesField(DOC_COUNT_FIELD, 4), new IntPoint(NUMBER_FIELD, 6)));
+            iw.addDocument(List.of(new NumericDocValuesField(DOC_COUNT_FIELD, 2), new IntPoint(NUMBER_FIELD, 5)));
+            iw.addDocument(
+                List.of(
+                    // Intentionally omit doc_count field
+                    new IntPoint(NUMBER_FIELD, 1)
+                )
+            );
+            iw.addDocument(
+                List.of(
+                    // Intentionally omit doc_count field
+                    new IntPoint(NUMBER_FIELD, 5)
+                )
+            );
+        }, global -> { assertEquals(3, global.getDocCount()); });
+    }
+
+    private void testAggregation(Query query, CheckedConsumer<RandomIndexWriter, IOException> indexer, Consumer<InternalGlobal> verify)
+        throws IOException {
+        GlobalAggregationBuilder aggregationBuilder = new GlobalAggregationBuilder("_name");
+        MappedFieldType fieldType = new NumberFieldMapper.NumberFieldType(NUMBER_FIELD, NumberFieldMapper.NumberType.LONG);
+        MappedFieldType docCountFieldType = new DocCountFieldMapper.DocCountFieldType();
+        testCase(aggregationBuilder, query, indexer, verify, fieldType, docCountFieldType);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/FiltersTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/FiltersTests.java
index f3408e09a4393..56f7f450dbdfb 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/FiltersTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/FiltersTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
@@ -106,7 +106,7 @@ public void testFiltersSortedByKey() {
     }
 
     public void testOtherBucket() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         builder.startObject();
         builder.startArray("filters").startObject().startObject("term").field("field", "foo").endObject().endObject().endArray();
         builder.endObject();
@@ -116,7 +116,7 @@ public void testOtherBucket() throws IOException {
             // The other bucket is disabled by default
             assertFalse(filters.otherBucket());
 
-            builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject();
             builder.startArray("filters").startObject().startObject("term").field("field", "foo").endObject().endObject().endArray();
             builder.field("other_bucket_key", "some_key");
@@ -128,7 +128,7 @@ public void testOtherBucket() throws IOException {
             // but setting a key enables it automatically
             assertTrue(filters.otherBucket());
 
-            builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject();
             builder.startArray("filters").startObject().startObject("term").field("field", "foo").endObject().endObject().endArray();
             builder.field("other_bucket", false);
@@ -207,7 +207,7 @@ public void testRewritePreservesOtherBucket() throws IOException {
 
     public void testEmptyFilters() throws IOException {
         {
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject();
             builder.startArray("filters").endArray();  // unkeyed array
             builder.endObject();
@@ -221,7 +221,7 @@ public void testEmptyFilters() throws IOException {
         }
 
         {
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             builder.startObject();
             builder.startObject("filters").endObject(); // keyed object
             builder.endObject();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoDistanceRangeTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoDistanceRangeTests.java
index 71b30798cf61c..c85ad6e215748 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoDistanceRangeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoDistanceRangeTests.java
@@ -35,9 +35,9 @@
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.bucket.range.GeoDistanceAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.range.GeoDistanceAggregationBuilder.Range;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoHashGridTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoHashGridTests.java
deleted file mode 100644
index b85761b709105..0000000000000
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoHashGridTests.java
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.bucket;
-
-import org.opensearch.LegacyESVersion;
-import org.opensearch.Version;
-import org.opensearch.common.geo.GeoBoundingBox;
-import org.opensearch.common.geo.GeoBoundingBoxTests;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.search.aggregations.BaseAggregationTestCase;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
-import org.opensearch.test.VersionUtils;
-
-import java.util.Collections;
-
-import static org.hamcrest.Matchers.equalTo;
-
-public class GeoHashGridTests extends BaseAggregationTestCase<GeoGridAggregationBuilder> {
-
-    @Override
-    protected GeoHashGridAggregationBuilder createTestAggregatorBuilder() {
-        String name = randomAlphaOfLengthBetween(3, 20);
-        GeoHashGridAggregationBuilder factory = new GeoHashGridAggregationBuilder(name);
-        factory.field("foo");
-        if (randomBoolean()) {
-            int precision = randomIntBetween(1, 12);
-            factory.precision(precision);
-        }
-        if (randomBoolean()) {
-            factory.size(randomIntBetween(1, Integer.MAX_VALUE));
-        }
-        if (randomBoolean()) {
-            factory.shardSize(randomIntBetween(1, Integer.MAX_VALUE));
-        }
-        if (randomBoolean()) {
-            factory.setGeoBoundingBox(GeoBoundingBoxTests.randomBBox());
-        }
-        return factory;
-    }
-
-    public void testSerializationPreBounds() throws Exception {
-        Version noBoundsSupportVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_0);
-        GeoHashGridAggregationBuilder builder = createTestAggregatorBuilder();
-        try (BytesStreamOutput output = new BytesStreamOutput()) {
-            output.setVersion(LegacyESVersion.V_7_6_0);
-            builder.writeTo(output);
-            try (
-                StreamInput in = new NamedWriteableAwareStreamInput(
-                    output.bytes().streamInput(),
-                    new NamedWriteableRegistry(Collections.emptyList())
-                )
-            ) {
-                in.setVersion(noBoundsSupportVersion);
-                GeoHashGridAggregationBuilder readBuilder = new GeoHashGridAggregationBuilder(in);
-                assertThat(
-                    readBuilder.geoBoundingBox(),
-                    equalTo(new GeoBoundingBox(new GeoPoint(Double.NaN, Double.NaN), new GeoPoint(Double.NaN, Double.NaN)))
-                );
-            }
-        }
-    }
-}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoTileGridTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoTileGridTests.java
deleted file mode 100644
index 3564ea337f741..0000000000000
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/GeoTileGridTests.java
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.bucket;
-
-import org.opensearch.LegacyESVersion;
-import org.opensearch.Version;
-import org.opensearch.common.geo.GeoBoundingBox;
-import org.opensearch.common.geo.GeoBoundingBoxTests;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.search.aggregations.BaseAggregationTestCase;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
-import org.opensearch.test.VersionUtils;
-
-import java.util.Collections;
-
-import static org.hamcrest.Matchers.equalTo;
-
-public class GeoTileGridTests extends BaseAggregationTestCase<GeoGridAggregationBuilder> {
-
-    @Override
-    protected GeoTileGridAggregationBuilder createTestAggregatorBuilder() {
-        String name = randomAlphaOfLengthBetween(3, 20);
-        GeoTileGridAggregationBuilder factory = new GeoTileGridAggregationBuilder(name);
-        factory.field("foo");
-        if (randomBoolean()) {
-            factory.precision(randomIntBetween(0, GeoTileUtils.MAX_ZOOM));
-        }
-        if (randomBoolean()) {
-            factory.size(randomIntBetween(1, Integer.MAX_VALUE));
-        }
-        if (randomBoolean()) {
-            factory.shardSize(randomIntBetween(1, Integer.MAX_VALUE));
-        }
-        if (randomBoolean()) {
-            factory.setGeoBoundingBox(GeoBoundingBoxTests.randomBBox());
-        }
-        return factory;
-    }
-
-    public void testSerializationPreBounds() throws Exception {
-        Version noBoundsSupportVersion = VersionUtils.randomVersionBetween(random(), LegacyESVersion.V_7_0_0, LegacyESVersion.V_7_5_0);
-        GeoTileGridAggregationBuilder builder = createTestAggregatorBuilder();
-        try (BytesStreamOutput output = new BytesStreamOutput()) {
-            output.setVersion(LegacyESVersion.V_7_6_0);
-            builder.writeTo(output);
-            try (
-                StreamInput in = new NamedWriteableAwareStreamInput(
-                    output.bytes().streamInput(),
-                    new NamedWriteableRegistry(Collections.emptyList())
-                )
-            ) {
-                in.setVersion(noBoundsSupportVersion);
-                GeoTileGridAggregationBuilder readBuilder = new GeoTileGridAggregationBuilder(in);
-                assertThat(
-                    readBuilder.geoBoundingBox(),
-                    equalTo(new GeoBoundingBox(new GeoPoint(Double.NaN, Double.NaN), new GeoPoint(Double.NaN, Double.NaN)))
-                );
-            }
-        }
-    }
-}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/GlobalAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/GlobalAggregatorTests.java
index abcaf06645a20..726fb4bcb741c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/GlobalAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/GlobalAggregatorTests.java
@@ -35,10 +35,10 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/HistogramTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/HistogramTests.java
index e233bee85462c..270ba863001c0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/HistogramTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/HistogramTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
-import org.opensearch.search.aggregations.bucket.histogram.HistogramAggregationBuilder;
 import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.bucket.histogram.HistogramAggregationBuilder;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -103,6 +103,19 @@ public void testInvalidBounds() {
         assertThat(ex.getMessage(), equalTo("max bound [0.4] must be greater than min bound [0.5]"));
     }
 
+    /**
+     * Check that minBound/maxBound does not throw {@link NullPointerException} when called before being set.
+     */
+    public void testMinBoundMaxBoundDefaultValues() {
+        HistogramAggregationBuilder factory = new HistogramAggregationBuilder("foo");
+
+        double minValue = factory.minBound();
+        double maxValue = factory.maxBound();
+
+        assertThat(minValue, equalTo(Double.POSITIVE_INFINITY));
+        assertThat(maxValue, equalTo(Double.NEGATIVE_INFINITY));
+    }
+
     private List<BucketOrder> randomOrder() {
         List<BucketOrder> orders = new ArrayList<>();
         switch (randomInt(4)) {
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollectorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollectorTests.java
index 051056f7e0fdc..21e08b034f1d0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollectorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/MergingBucketsDeferringCollectorTests.java
@@ -73,16 +73,7 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
         }, (deferringCollector, finalCollector) -> {
             deferringCollector.prepareSelectedBuckets(0, 8, 9);
 
-            equalTo(
-                org.opensearch.common.collect.Map.of(
-                    0L,
-                    org.opensearch.common.collect.List.of(0, 1, 2, 3, 4, 5, 6, 7),
-                    1L,
-                    org.opensearch.common.collect.List.of(8),
-                    2L,
-                    org.opensearch.common.collect.List.of(9)
-                )
-            );
+            equalTo(Map.of(0L, List.of(0, 1, 2, 3, 4, 5, 6, 7), 1L, List.of(8), 2L, List.of(9)));
         });
     }
 
@@ -99,19 +90,7 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
         }, (deferringCollector, finalCollector) -> {
             deferringCollector.prepareSelectedBuckets(0, 8, 9);
 
-            assertThat(
-                finalCollector.collection,
-                equalTo(
-                    org.opensearch.common.collect.Map.of(
-                        0L,
-                        org.opensearch.common.collect.List.of(4, 5, 6, 7),
-                        1L,
-                        org.opensearch.common.collect.List.of(8),
-                        2L,
-                        org.opensearch.common.collect.List.of(9)
-                    )
-                )
-            );
+            assertThat(finalCollector.collection, equalTo(Map.of(0L, List.of(4, 5, 6, 7), 1L, List.of(8), 2L, List.of(9))));
         });
     }
 
@@ -129,19 +108,7 @@ public void collect(int doc, long owningBucketOrd) throws IOException {
         }, (deferringCollector, finalCollector) -> {
             deferringCollector.prepareSelectedBuckets(0, 8, 9);
 
-            assertThat(
-                finalCollector.collection,
-                equalTo(
-                    org.opensearch.common.collect.Map.of(
-                        0L,
-                        org.opensearch.common.collect.List.of(0, 1, 2, 3),
-                        1L,
-                        org.opensearch.common.collect.List.of(8),
-                        2L,
-                        org.opensearch.common.collect.List.of(9)
-                    )
-                )
-            );
+            assertThat(finalCollector.collection, equalTo(Map.of(0L, List.of(0, 1, 2, 3), 1L, List.of(8), 2L, List.of(9))));
         });
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/RangeTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/RangeTests.java
index 831f488ba1a59..c8a6f5e923d5a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/RangeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/RangeTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket;
 
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.bucket.range.RangeAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.range.RangeAggregator.Range;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/RareTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/RareTermsTests.java
index 799faecb5ab57..6b8655eccd74d 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/RareTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/RareTermsTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
 import org.opensearch.search.aggregations.bucket.terms.RareTermsAggregationBuilder;
@@ -59,13 +58,13 @@ protected RareTermsAggregationBuilder createTestAggregatorBuilder() {
             IncludeExclude incExc = null;
             switch (randomInt(6)) {
                 case 0:
-                    incExc = new IncludeExclude(new RegExp("foobar"), null);
+                    incExc = new IncludeExclude("foobar", null);
                     break;
                 case 1:
-                    incExc = new IncludeExclude(null, new RegExp("foobaz"));
+                    incExc = new IncludeExclude(null, "foobaz");
                     break;
                 case 2:
-                    incExc = new IncludeExclude(new RegExp("foobar"), new RegExp("foobaz"));
+                    incExc = new IncludeExclude("foobar", "foobaz");
                     break;
                 case 3:
                     SortedSet<BytesRef> includeValues = new TreeSet<>();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/ShardSizeTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/ShardSizeTestCase.java
index d6981d1c34652..21d05305eed1b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/ShardSizeTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/ShardSizeTestCase.java
@@ -32,21 +32,44 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.is;
 
-public abstract class ShardSizeTestCase extends OpenSearchIntegTestCase {
+public abstract class ShardSizeTestCase extends ParameterizedOpenSearchIntegTestCase {
+
+    public ShardSizeTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected int numberOfShards() {
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/SignificantTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/SignificantTermsTests.java
index 3001f8ede7f4d..6312d6c175866 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/SignificantTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/SignificantTermsTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
@@ -160,13 +159,13 @@ static IncludeExclude getIncludeExclude() {
         IncludeExclude incExc = null;
         switch (randomInt(5)) {
             case 0:
-                incExc = new IncludeExclude(new RegExp("foobar"), null);
+                incExc = new IncludeExclude("foobar", null);
                 break;
             case 1:
-                incExc = new IncludeExclude(null, new RegExp("foobaz"));
+                incExc = new IncludeExclude(null, "foobaz");
                 break;
             case 2:
-                incExc = new IncludeExclude(new RegExp("foobar"), new RegExp("foobaz"));
+                incExc = new IncludeExclude("foobar", "foobaz");
                 break;
             case 3:
                 SortedSet<BytesRef> includeValues = new TreeSet<>();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/TermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/TermsTests.java
index eb4f33c6f8e19..04e7fad2105ec 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/TermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/TermsTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.search.aggregations.bucket;
 
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 import org.opensearch.search.aggregations.BucketOrder;
@@ -118,13 +117,13 @@ protected TermsAggregationBuilder createTestAggregatorBuilder() {
             IncludeExclude incExc = null;
             switch (randomInt(6)) {
                 case 0:
-                    incExc = new IncludeExclude(new RegExp("foobar"), null);
+                    incExc = new IncludeExclude("foobar", null);
                     break;
                 case 1:
-                    incExc = new IncludeExclude(null, new RegExp("foobaz"));
+                    incExc = new IncludeExclude(null, "foobaz");
                     break;
                 case 2:
-                    incExc = new IncludeExclude(new RegExp("foobar"), new RegExp("foobaz"));
+                    incExc = new IncludeExclude("foobar", "foobaz");
                     break;
                 case 3:
                     SortedSet<BytesRef> includeValues = new TreeSet<>();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilderTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilderTests.java
index c4a87f3993bb4..9290183ec7312 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregationBuilderTests.java
@@ -32,10 +32,8 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.opensearch.common.geo.GeoBoundingBoxTests;
 import org.opensearch.script.Script;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 import org.opensearch.search.sort.SortOrder;
@@ -74,17 +72,6 @@ private DateHistogramValuesSourceBuilder randomDateHistogramSourceBuilder() {
         return histo;
     }
 
-    private GeoTileGridValuesSourceBuilder randomGeoTileGridValuesSourceBuilder() {
-        GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder(randomAlphaOfLengthBetween(5, 10));
-        if (randomBoolean()) {
-            geoTile.precision(randomIntBetween(0, GeoTileUtils.MAX_ZOOM));
-        }
-        if (randomBoolean()) {
-            geoTile.geoBoundingBox(GeoBoundingBoxTests.randomBBox());
-        }
-        return geoTile;
-    }
-
     private TermsValuesSourceBuilder randomTermsSourceBuilder() {
         TermsValuesSourceBuilder terms = new TermsValuesSourceBuilder(randomAlphaOfLengthBetween(5, 10));
         if (randomBoolean()) {
@@ -118,11 +105,9 @@ private HistogramValuesSourceBuilder randomHistogramSourceBuilder() {
     @Override
     protected CompositeAggregationBuilder createTestAggregatorBuilder() {
         int numSources = randomIntBetween(1, 10);
-        numSources = 1;
         List<CompositeValuesSourceBuilder<?>> sources = new ArrayList<>();
         for (int i = 0; i < numSources; i++) {
-            int type = randomIntBetween(0, 3);
-            type = 3;
+            int type = randomIntBetween(0, 2);
             switch (type) {
                 case 0:
                     sources.add(randomTermsSourceBuilder());
@@ -133,9 +118,6 @@ protected CompositeAggregationBuilder createTestAggregatorBuilder() {
                 case 2:
                     sources.add(randomHistogramSourceBuilder());
                     break;
-                case 3:
-                    sources.add(randomGeoTileGridValuesSourceBuilder());
-                    break;
                 default:
                     throw new AssertionError("wrong branch");
             }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregatorTests.java
index 88b2323b8adfc..eabc4b7764eed 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeAggregatorTests.java
@@ -32,68 +32,24 @@
 
 package org.opensearch.search.aggregations.bucket.composite;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
-import org.apache.lucene.document.Document;
-import org.apache.lucene.document.DoublePoint;
-import org.apache.lucene.document.Field;
-import org.apache.lucene.document.InetAddressPoint;
-import org.apache.lucene.document.IntPoint;
-import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.document.LongPoint;
-import org.apache.lucene.document.SortedNumericDocValuesField;
-import org.apache.lucene.document.SortedSetDocValuesField;
-import org.apache.lucene.document.StringField;
-import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
-import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.search.Sort;
-import org.apache.lucene.search.SortField;
-import org.apache.lucene.search.SortedNumericSortField;
-import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.NumericUtils;
-import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.time.DateFormatters;
-import org.opensearch.index.Index;
-import org.opensearch.index.IndexSettings;
-import org.opensearch.index.mapper.DateFieldMapper;
-import org.opensearch.index.mapper.DocumentMapper;
-import org.opensearch.index.mapper.GeoPointFieldMapper;
-import org.opensearch.index.mapper.IpFieldMapper;
-import org.opensearch.index.mapper.KeywordFieldMapper;
-import org.opensearch.index.mapper.MappedFieldType;
-import org.opensearch.index.mapper.MapperService;
-import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.search.aggregations.Aggregator;
-import org.opensearch.search.aggregations.AggregatorTestCase;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils;
 import org.opensearch.search.aggregations.bucket.histogram.DateHistogramInterval;
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
+import org.opensearch.search.aggregations.composite.BaseCompositeAggregatorTestCase;
 import org.opensearch.search.aggregations.metrics.InternalMax;
 import org.opensearch.search.aggregations.metrics.MaxAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.TopHits;
 import org.opensearch.search.aggregations.metrics.TopHitsAggregationBuilder;
 import org.opensearch.search.aggregations.support.ValueType;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.IndexSettingsModule;
-import org.junit.After;
-import org.junit.Before;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -109,51 +65,14 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
-import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
-import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-public class CompositeAggregatorTests extends AggregatorTestCase {
-    private static MappedFieldType[] FIELD_TYPES;
-
-    @Override
-    @Before
-    public void setUp() throws Exception {
-        super.setUp();
-        FIELD_TYPES = new MappedFieldType[8];
-        FIELD_TYPES[0] = new KeywordFieldMapper.KeywordFieldType("keyword");
-        FIELD_TYPES[1] = new NumberFieldMapper.NumberFieldType("long", NumberFieldMapper.NumberType.LONG);
-        FIELD_TYPES[2] = new NumberFieldMapper.NumberFieldType("double", NumberFieldMapper.NumberType.DOUBLE);
-        FIELD_TYPES[3] = new DateFieldMapper.DateFieldType("date", DateFormatter.forPattern("yyyy-MM-dd||epoch_millis"));
-        FIELD_TYPES[4] = new NumberFieldMapper.NumberFieldType("price", NumberFieldMapper.NumberType.INTEGER);
-        FIELD_TYPES[5] = new KeywordFieldMapper.KeywordFieldType("terms");
-        FIELD_TYPES[6] = new IpFieldMapper.IpFieldType("ip");
-        FIELD_TYPES[7] = new GeoPointFieldMapper.GeoPointFieldType("geo_point");
-    }
 
-    @Override
-    @After
-    public void tearDown() throws Exception {
-        super.tearDown();
-        FIELD_TYPES = null;
-    }
-
-    @Override
-    protected MapperService mapperServiceMock() {
-        MapperService mapperService = mock(MapperService.class);
-        DocumentMapper mapper = mock(DocumentMapper.class);
-        when(mapper.typeText()).thenReturn(new Text("_doc"));
-        when(mapper.type()).thenReturn("_doc");
-        when(mapperService.documentMapper()).thenReturn(mapper);
-        return mapperService;
-    }
+public class CompositeAggregatorTests extends BaseCompositeAggregatorTestCase {
 
     public void testUnmappedFieldWithTerms() throws Exception {
         final List<Map<String, List<Object>>> dataset = new ArrayList<>();
@@ -170,7 +89,9 @@ public void testUnmappedFieldWithTerms() throws Exception {
             Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery("keyword")),
             dataset,
             () -> new CompositeAggregationBuilder("name", Arrays.asList(new TermsValuesSourceBuilder("unmapped").field("unmapped"))),
-            (result) -> { assertEquals(0, result.getBuckets().size()); }
+            (result) -> {
+                assertEquals(0, result.getBuckets().size());
+            }
         );
 
         testSearchCase(
@@ -195,7 +116,9 @@ public void testUnmappedFieldWithTerms() throws Exception {
                 "name",
                 Arrays.asList(new TermsValuesSourceBuilder("unmapped").field("unmapped").missingBucket(true))
             ).aggregateAfter(Collections.singletonMap("unmapped", null)),
-            (result) -> { assertEquals(0, result.getBuckets().size()); }
+            (result) -> {
+                assertEquals(0, result.getBuckets().size());
+            }
         );
 
         testSearchCase(
@@ -208,7 +131,9 @@ public void testUnmappedFieldWithTerms() throws Exception {
                     new TermsValuesSourceBuilder("unmapped").field("unmapped")
                 )
             ),
-            (result) -> { assertEquals(0, result.getBuckets().size()); }
+            (result) -> {
+                assertEquals(0, result.getBuckets().size());
+            }
         );
 
         testSearchCase(
@@ -234,80 +159,6 @@ public void testUnmappedFieldWithTerms() throws Exception {
         );
     }
 
-    public void testUnmappedFieldWithGeopoint() throws Exception {
-        final List<Map<String, List<Object>>> dataset = new ArrayList<>();
-        final String mappedFieldName = "geo_point";
-        dataset.addAll(
-            Arrays.asList(
-                createDocument(mappedFieldName, new GeoPoint(48.934059, 41.610741)),
-                createDocument(mappedFieldName, new GeoPoint(-23.065941, 113.610741)),
-                createDocument(mappedFieldName, new GeoPoint(90.0, 0.0)),
-                createDocument(mappedFieldName, new GeoPoint(37.2343, -115.8067)),
-                createDocument(mappedFieldName, new GeoPoint(90.0, 0.0))
-            )
-        );
-
-        // just unmapped = no results
-        testSearchCase(
-            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
-            dataset,
-            () -> new CompositeAggregationBuilder("name", Arrays.asList(new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped"))),
-            (result) -> assertEquals(0, result.getBuckets().size())
-        );
-
-        // unmapped missing bucket = one result
-        testSearchCase(
-            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
-            dataset,
-            () -> new CompositeAggregationBuilder(
-                "name",
-                Arrays.asList(new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped").missingBucket(true))
-            ),
-            (result) -> {
-                assertEquals(1, result.getBuckets().size());
-                assertEquals("{unmapped=null}", result.afterKey().toString());
-                assertEquals("{unmapped=null}", result.getBuckets().get(0).getKeyAsString());
-                assertEquals(5L, result.getBuckets().get(0).getDocCount());
-            }
-        );
-
-        // field + unmapped, no missing bucket = no results
-        testSearchCase(
-            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
-            dataset,
-            () -> new CompositeAggregationBuilder(
-                "name",
-                Arrays.asList(
-                    new GeoTileGridValuesSourceBuilder(mappedFieldName).field(mappedFieldName),
-                    new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped")
-                )
-            ),
-            (result) -> assertEquals(0, result.getBuckets().size())
-        );
-
-        // field + unmapped with missing bucket = multiple results
-        testSearchCase(
-            Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery(mappedFieldName)),
-            dataset,
-            () -> new CompositeAggregationBuilder(
-                "name",
-                Arrays.asList(
-                    new GeoTileGridValuesSourceBuilder(mappedFieldName).field(mappedFieldName),
-                    new GeoTileGridValuesSourceBuilder("unmapped").field("unmapped").missingBucket(true)
-                )
-            ),
-            (result) -> {
-                assertEquals(2, result.getBuckets().size());
-                assertEquals("{geo_point=7/64/56, unmapped=null}", result.afterKey().toString());
-                assertEquals("{geo_point=7/32/56, unmapped=null}", result.getBuckets().get(0).getKeyAsString());
-                assertEquals(2L, result.getBuckets().get(0).getDocCount());
-                assertEquals("{geo_point=7/64/56, unmapped=null}", result.getBuckets().get(1).getKeyAsString());
-                assertEquals(3L, result.getBuckets().get(1).getDocCount());
-            }
-        );
-
-    }
-
     public void testUnmappedFieldWithHistogram() throws Exception {
         final List<Map<String, List<Object>>> dataset = new ArrayList<>();
         final String mappedFieldName = "price";
@@ -2483,42 +2334,6 @@ public void testWithIP() throws Exception {
         });
     }
 
-    public void testWithGeoPoint() throws Exception {
-        final List<Map<String, List<Object>>> dataset = new ArrayList<>();
-        dataset.addAll(
-            Arrays.asList(
-                createDocument("geo_point", new GeoPoint(48.934059, 41.610741)),
-                createDocument("geo_point", new GeoPoint(-23.065941, 113.610741)),
-                createDocument("geo_point", new GeoPoint(90.0, 0.0)),
-                createDocument("geo_point", new GeoPoint(37.2343, -115.8067)),
-                createDocument("geo_point", new GeoPoint(90.0, 0.0))
-            )
-        );
-        testSearchCase(Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery("geo_point")), dataset, () -> {
-            GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder("geo_point").field("geo_point");
-            return new CompositeAggregationBuilder("name", Collections.singletonList(geoTile));
-        }, (result) -> {
-            assertEquals(2, result.getBuckets().size());
-            assertEquals("{geo_point=7/64/56}", result.afterKey().toString());
-            assertEquals("{geo_point=7/32/56}", result.getBuckets().get(0).getKeyAsString());
-            assertEquals(2L, result.getBuckets().get(0).getDocCount());
-            assertEquals("{geo_point=7/64/56}", result.getBuckets().get(1).getKeyAsString());
-            assertEquals(3L, result.getBuckets().get(1).getDocCount());
-        });
-
-        testSearchCase(Arrays.asList(new MatchAllDocsQuery(), new DocValuesFieldExistsQuery("geo_point")), dataset, () -> {
-            GeoTileGridValuesSourceBuilder geoTile = new GeoTileGridValuesSourceBuilder("geo_point").field("geo_point");
-            return new CompositeAggregationBuilder("name", Collections.singletonList(geoTile)).aggregateAfter(
-                Collections.singletonMap("geo_point", "7/32/56")
-            );
-        }, (result) -> {
-            assertEquals(1, result.getBuckets().size());
-            assertEquals("{geo_point=7/64/56}", result.afterKey().toString());
-            assertEquals("{geo_point=7/64/56}", result.getBuckets().get(0).getKeyAsString());
-            assertEquals(3L, result.getBuckets().get(0).getDocCount());
-        });
-    }
-
     public void testEarlyTermination() throws Exception {
         final List<Map<String, List<Object>>> dataset = new ArrayList<>();
         dataset.addAll(
@@ -2648,193 +2463,4 @@ public void testIndexSortWithDuplicate() throws Exception {
             );
         }
     }
-
-    private void testSearchCase(
-        List<Query> queries,
-        List<Map<String, List<Object>>> dataset,
-        Supplier<CompositeAggregationBuilder> create,
-        Consumer<InternalComposite> verify
-    ) throws IOException {
-        for (Query query : queries) {
-            executeTestCase(false, false, query, dataset, create, verify);
-            executeTestCase(false, true, query, dataset, create, verify);
-        }
-    }
-
-    private void executeTestCase(
-        boolean forceMerge,
-        boolean useIndexSort,
-        Query query,
-        List<Map<String, List<Object>>> dataset,
-        Supplier<CompositeAggregationBuilder> create,
-        Consumer<InternalComposite> verify
-    ) throws IOException {
-        Map<String, MappedFieldType> types = Arrays.stream(FIELD_TYPES)
-            .collect(Collectors.toMap(MappedFieldType::name, Function.identity()));
-        CompositeAggregationBuilder aggregationBuilder = create.get();
-        Sort indexSort = useIndexSort ? buildIndexSort(aggregationBuilder.sources(), types) : null;
-        IndexSettings indexSettings = createIndexSettings(indexSort);
-        try (Directory directory = newDirectory()) {
-            IndexWriterConfig config = newIndexWriterConfig(random(), new MockAnalyzer(random()));
-            if (indexSort != null) {
-                config.setIndexSort(indexSort);
-                config.setCodec(TestUtil.getDefaultCodec());
-            }
-            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory, config)) {
-                Document document = new Document();
-                int id = 0;
-                for (Map<String, List<Object>> fields : dataset) {
-                    document.clear();
-                    addToDocument(id, document, fields);
-                    indexWriter.addDocument(document);
-                    id++;
-                }
-                if (forceMerge || rarely()) {
-                    // forceMerge randomly or if the collector-per-leaf testing stuff would break the tests.
-                    indexWriter.forceMerge(1);
-                } else {
-                    if (dataset.size() > 0) {
-                        int numDeletes = randomIntBetween(1, 25);
-                        for (int i = 0; i < numDeletes; i++) {
-                            id = randomIntBetween(0, dataset.size() - 1);
-                            indexWriter.deleteDocuments(new Term("id", Integer.toString(id)));
-                            document.clear();
-                            addToDocument(id, document, dataset.get(id));
-                            indexWriter.addDocument(document);
-                        }
-                    }
-
-                }
-            }
-            try (IndexReader indexReader = DirectoryReader.open(directory)) {
-                IndexSearcher indexSearcher = new IndexSearcher(indexReader);
-                InternalComposite composite = searchAndReduce(indexSettings, indexSearcher, query, aggregationBuilder, FIELD_TYPES);
-                verify.accept(composite);
-            }
-        }
-    }
-
-    private static IndexSettings createIndexSettings(Sort sort) {
-        Settings.Builder builder = Settings.builder();
-        if (sort != null) {
-            String[] fields = Arrays.stream(sort.getSort()).map(SortField::getField).toArray(String[]::new);
-            String[] orders = Arrays.stream(sort.getSort()).map((o) -> o.getReverse() ? "desc" : "asc").toArray(String[]::new);
-            builder.putList("index.sort.field", fields);
-            builder.putList("index.sort.order", orders);
-        }
-        return IndexSettingsModule.newIndexSettings(new Index("_index", "0"), builder.build());
-    }
-
-    private void addToDocument(int id, Document doc, Map<String, List<Object>> keys) {
-        doc.add(new StringField("id", Integer.toString(id), Field.Store.NO));
-        for (Map.Entry<String, List<Object>> entry : keys.entrySet()) {
-            final String name = entry.getKey();
-            for (Object value : entry.getValue()) {
-                if (value instanceof Integer) {
-                    doc.add(new SortedNumericDocValuesField(name, (int) value));
-                    doc.add(new IntPoint(name, (int) value));
-                } else if (value instanceof Long) {
-                    doc.add(new SortedNumericDocValuesField(name, (long) value));
-                    doc.add(new LongPoint(name, (long) value));
-                } else if (value instanceof Double) {
-                    doc.add(new SortedNumericDocValuesField(name, NumericUtils.doubleToSortableLong((double) value)));
-                    doc.add(new DoublePoint(name, (double) value));
-                } else if (value instanceof String) {
-                    doc.add(new SortedSetDocValuesField(name, new BytesRef((String) value)));
-                    doc.add(new StringField(name, new BytesRef((String) value), Field.Store.NO));
-                } else if (value instanceof InetAddress) {
-                    doc.add(new SortedSetDocValuesField(name, new BytesRef(InetAddressPoint.encode((InetAddress) value))));
-                    doc.add(new InetAddressPoint(name, (InetAddress) value));
-                } else if (value instanceof GeoPoint) {
-                    GeoPoint point = (GeoPoint) value;
-                    doc.add(
-                        new SortedNumericDocValuesField(
-                            name,
-                            GeoTileUtils.longEncode(point.lon(), point.lat(), GeoTileGridAggregationBuilder.DEFAULT_PRECISION)
-                        )
-                    );
-                    doc.add(new LatLonPoint(name, point.lat(), point.lon()));
-                } else {
-                    throw new AssertionError("invalid object: " + value.getClass().getSimpleName());
-                }
-            }
-        }
-    }
-
-    private static Map<String, Object> createAfterKey(Object... fields) {
-        assert fields.length % 2 == 0;
-        final Map<String, Object> map = new HashMap<>();
-        for (int i = 0; i < fields.length; i += 2) {
-            String field = (String) fields[i];
-            map.put(field, fields[i + 1]);
-        }
-        return map;
-    }
-
-    @SuppressWarnings("unchecked")
-    private static Map<String, List<Object>> createDocument(Object... fields) {
-        assert fields.length % 2 == 0;
-        final Map<String, List<Object>> map = new HashMap<>();
-        for (int i = 0; i < fields.length; i += 2) {
-            String field = (String) fields[i];
-            if (fields[i + 1] instanceof List) {
-                map.put(field, (List<Object>) fields[i + 1]);
-            } else {
-                map.put(field, Collections.singletonList(fields[i + 1]));
-            }
-        }
-        return map;
-    }
-
-    private static long asLong(String dateTime) {
-        return DateFormatters.from(DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.parse(dateTime)).toInstant().toEpochMilli();
-    }
-
-    private static Sort buildIndexSort(List<CompositeValuesSourceBuilder<?>> sources, Map<String, MappedFieldType> fieldTypes) {
-        List<SortField> sortFields = new ArrayList<>();
-        Map<String, MappedFieldType> remainingFieldTypes = new HashMap<>(fieldTypes);
-        for (CompositeValuesSourceBuilder<?> source : sources) {
-            MappedFieldType type = fieldTypes.remove(source.field());
-            remainingFieldTypes.remove(source.field());
-            SortField sortField = sortFieldFrom(type);
-            if (sortField == null) {
-                break;
-            }
-            sortFields.add(sortField);
-        }
-        while (remainingFieldTypes.size() > 0 && randomBoolean()) {
-            // Add extra unused sorts
-            List<String> fields = new ArrayList<>(remainingFieldTypes.keySet());
-            Collections.sort(fields);
-            String field = fields.get(between(0, fields.size() - 1));
-            SortField sortField = sortFieldFrom(remainingFieldTypes.remove(field));
-            if (sortField != null) {
-                sortFields.add(sortField);
-            }
-        }
-        return sortFields.size() > 0 ? new Sort(sortFields.toArray(new SortField[0])) : null;
-    }
-
-    private static SortField sortFieldFrom(MappedFieldType type) {
-        if (type instanceof KeywordFieldMapper.KeywordFieldType) {
-            return new SortedSetSortField(type.name(), false);
-        } else if (type instanceof DateFieldMapper.DateFieldType) {
-            return new SortedNumericSortField(type.name(), SortField.Type.LONG, false);
-        } else if (type instanceof NumberFieldMapper.NumberFieldType) {
-            switch (type.typeName()) {
-                case "byte":
-                case "short":
-                case "integer":
-                    return new SortedNumericSortField(type.name(), SortField.Type.INT, false);
-                case "long":
-                    return new SortedNumericSortField(type.name(), SortField.Type.LONG, false);
-                case "float":
-                case "double":
-                    return new SortedNumericSortField(type.name(), SortField.Type.DOUBLE, false);
-                default:
-                    return null;
-            }
-        }
-        return null;
-    }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueueTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueueTests.java
index 3dccdf8dab95e..74673b56a7de5 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueueTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/CompositeValuesCollectorQueueTests.java
@@ -43,7 +43,7 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
 import org.apache.lucene.search.CollectionTerminatedException;
 import org.apache.lucene.search.DocIdSet;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -52,6 +52,7 @@
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
@@ -66,6 +67,7 @@
 import org.opensearch.search.aggregations.bucket.missing.MissingOrder;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -74,6 +76,7 @@
 
 import static org.opensearch.index.mapper.NumberFieldMapper.NumberType.DOUBLE;
 import static org.opensearch.index.mapper.NumberFieldMapper.NumberType.LONG;
+import static org.opensearch.index.mapper.NumberFieldMapper.NumberType.UNSIGNED_LONG;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 
@@ -103,6 +106,13 @@ public void testRandomDoubleAndLong() throws IOException {
         );
     }
 
+    public void testRandomDoubleAndUnsignedLong() throws IOException {
+        testRandomCase(
+            new ClassAndName(createNumber("double", DOUBLE), Double.class),
+            new ClassAndName(createNumber("unsigned_long", UNSIGNED_LONG), BigInteger.class)
+        );
+    }
+
     public void testRandomDoubleAndKeyword() throws IOException {
         testRandomCase(
             new ClassAndName(createNumber("double", DOUBLE), Double.class),
@@ -128,6 +138,13 @@ public void testRandomLongAndDouble() throws IOException {
         );
     }
 
+    public void testRandomLongAndUnsignedLong() throws IOException {
+        testRandomCase(
+            new ClassAndName(createNumber("long", LONG), Long.class),
+            new ClassAndName(createNumber("unsigned_long", UNSIGNED_LONG), BigInteger.class)
+        );
+    }
+
     public void testRandomKeywordAndLong() throws IOException {
         testRandomCase(
             new ClassAndName(createKeyword("keyword"), BytesRef.class),
@@ -191,6 +208,13 @@ private void testRandomCase(boolean forceMerge, boolean missingBucket, int index
                 for (int j = 0; j < numValues; j++) {
                     values[j] = randomLong();
                 }
+            } else if (type.clazz == BigInteger.class) {
+                if (i < indexSortSourcePrefix) {
+                    indexSortFields[i] = new SortedNumericSortField(type.fieldType.name(), SortField.Type.LONG);
+                }
+                for (int j = 0; j < numValues; j++) {
+                    values[j] = randomUnsignedLong();
+                }
             } else if (type.clazz == Double.class) {
                 if (i < indexSortSourcePrefix) {
                     indexSortFields[i] = new SortedNumericSortField(type.fieldType.name(), SortField.Type.DOUBLE);
@@ -237,6 +261,15 @@ private void testRandomCase(boolean forceMerge, boolean missingBucket, int index
                                     long value = (Long) values.get(k);
                                     document.add(new SortedNumericDocValuesField(types[j].fieldType.name(), value));
                                     document.add(new LongPoint(types[j].fieldType.name(), value));
+                                } else if (types[j].clazz == BigInteger.class) {
+                                    BigInteger value = (BigInteger) values.get(k);
+                                    document.add(
+                                        new SortedNumericDocValuesField(
+                                            types[j].fieldType.name(),
+                                            NumericUtils.doubleToSortableLong(value.doubleValue())
+                                        )
+                                    );
+                                    document.add(new BigIntegerPoint(types[j].fieldType.name(), value));
                                 } else if (types[j].clazz == Double.class) {
                                     document.add(
                                         new SortedNumericDocValuesField(
@@ -293,6 +326,17 @@ private void testRandomCase(boolean forceMerge, boolean missingBucket, int index
                         size,
                         1
                     );
+                } else if (types[i].clazz == BigInteger.class) {
+                    sources[i] = new DoubleValuesSource(
+                        bigArrays,
+                        fieldType,
+                        context -> FieldData.sortableLongBitsToDoubles(DocValues.getSortedNumeric(context.reader(), fieldType.name())),
+                        DocValueFormat.RAW,
+                        missingBucket,
+                        MissingOrder.DEFAULT,
+                        size,
+                        1
+                    );
                 } else if (types[i].clazz == BytesRef.class) {
                     if (forceMerge) {
                         // we don't create global ordinals but we test this mode when the reader has a single segment
@@ -347,7 +391,7 @@ private void testRandomCase(boolean forceMerge, boolean missingBucket, int index
                             final LeafBucketCollector leafCollector = new LeafBucketCollector() {
                                 @Override
                                 public void collect(int doc, long bucket) throws IOException {
-                                    queue.addIfCompetitive(indexSortSourcePrefix);
+                                    queue.addIfCompetitive(indexSortSourcePrefix, 1);
                                 }
                             };
                             final LeafBucketCollector queueCollector = queue.getLeafCollector(leafReaderContext, leafCollector);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/InternalCompositeTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/InternalCompositeTests.java
index 4121954c1ede2..59bc3a31a5a8a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/InternalCompositeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/InternalCompositeTests.java
@@ -57,7 +57,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.randomAsciiLettersOfLengthBetween;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.stream.Collectors.toList;
@@ -67,6 +66,7 @@
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.randomAsciiLettersOfLengthBetween;
 
 public class InternalCompositeTests extends InternalMultiBucketAggregationTestCase<InternalComposite> {
     private List<String> sourceNames;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSourceTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSourceTests.java
index 6569a269169eb..1b9c95b87d4c2 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSourceTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/composite/SingleDimensionValuesSourceTests.java
@@ -184,7 +184,8 @@ public void testNumericSorted() {
             if (numberType == NumberFieldMapper.NumberType.BYTE
                 || numberType == NumberFieldMapper.NumberType.SHORT
                 || numberType == NumberFieldMapper.NumberType.INTEGER
-                || numberType == NumberFieldMapper.NumberType.LONG) {
+                || numberType == NumberFieldMapper.NumberType.LONG
+                || numberType == NumberFieldMapper.NumberType.UNSIGNED_LONG) {
 
                 source = new LongValuesSource(
                     BigArrays.NON_RECYCLING_INSTANCE,
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorTests.java
index 4ed95bf7391a6..2125748cd9661 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FilterAggregatorTests.java
@@ -35,10 +35,10 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.MatchAllQueryBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorTests.java
index 8ff2e57d5dbb6..38530d8ccc623 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/FiltersAggregatorTests.java
@@ -35,10 +35,10 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.query.QueryBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFilterTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFilterTests.java
index b856a81515b52..110773a82404d 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFilterTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFilterTests.java
@@ -92,7 +92,7 @@ public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext
             }
         };
         PipelineTree tree = new PipelineTree(
-            org.opensearch.common.collect.Map.of(inner.getName(), new PipelineTree(emptyMap(), singletonList(mockPipeline))),
+            Map.of(inner.getName(), new PipelineTree(emptyMap(), singletonList(mockPipeline))),
             emptyList()
         );
         InternalFilter reduced = (InternalFilter) test.reducePipelines(test, emptyReduceContextBuilder().forFinalReduction(), tree);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFiltersTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFiltersTests.java
index 176bfefdefc1e..038efc9f7c4f4 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFiltersTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/filter/InternalFiltersTests.java
@@ -156,7 +156,7 @@ public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext
             }
         };
         PipelineTree tree = new PipelineTree(
-            org.opensearch.common.collect.Map.of(inner.getName(), new PipelineTree(emptyMap(), singletonList(mockPipeline))),
+            Map.of(inner.getName(), new PipelineTree(emptyMap(), singletonList(mockPipeline))),
             emptyList()
         );
         InternalFilters reduced = (InternalFilters) test.reducePipelines(test, emptyReduceContextBuilder().forFinalReduction(), tree);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridTests.java
deleted file mode 100644
index 5a26ec759281c..0000000000000
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoHashGridTests.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.bucket.geogrid;
-
-import org.opensearch.geometry.utils.Geohash;
-import org.opensearch.search.aggregations.InternalAggregations;
-
-import java.util.List;
-import java.util.Map;
-
-public class GeoHashGridTests extends GeoGridTestCase<InternalGeoHashGridBucket, InternalGeoHashGrid> {
-
-    @Override
-    protected InternalGeoHashGrid createInternalGeoGrid(
-        String name,
-        int size,
-        List<InternalGeoGridBucket> buckets,
-        Map<String, Object> metadata
-    ) {
-        return new InternalGeoHashGrid(name, size, buckets, metadata);
-    }
-
-    @Override
-    protected InternalGeoHashGridBucket createInternalGeoGridBucket(Long key, long docCount, InternalAggregations aggregations) {
-        return new InternalGeoHashGridBucket(key, docCount, aggregations);
-    }
-
-    @Override
-    protected long longEncode(double lng, double lat, int precision) {
-        return Geohash.longEncode(lng, lat, precision);
-    }
-
-    @Override
-    protected int randomPrecision() {
-        return randomIntBetween(4, 12);
-    }
-}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridTests.java
deleted file mode 100644
index 50b9a8cd762d1..0000000000000
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileGridTests.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.bucket.geogrid;
-
-import org.opensearch.search.aggregations.InternalAggregations;
-
-import java.util.List;
-import java.util.Map;
-
-public class GeoTileGridTests extends GeoGridTestCase<InternalGeoTileGridBucket, InternalGeoTileGrid> {
-
-    @Override
-    protected InternalGeoTileGrid createInternalGeoGrid(
-        String name,
-        int size,
-        List<InternalGeoGridBucket> buckets,
-        Map<String, Object> metadata
-    ) {
-        return new InternalGeoTileGrid(name, size, buckets, metadata);
-    }
-
-    @Override
-    protected InternalGeoTileGridBucket createInternalGeoGridBucket(Long key, long docCount, InternalAggregations aggregations) {
-        return new InternalGeoTileGridBucket(key, docCount, aggregations);
-    }
-
-    @Override
-    protected long longEncode(double lng, double lat, int precision) {
-        return GeoTileUtils.longEncode(lng, lat, precision);
-    }
-
-    @Override
-    protected int randomPrecision() {
-        // precision values below 8 can lead to parsing errors
-        return randomIntBetween(8, GeoTileUtils.MAX_ZOOM);
-    }
-}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtilsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtilsTests.java
index dfe4034650594..1443208a1d2fc 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtilsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/geogrid/GeoTileUtilsTests.java
@@ -34,14 +34,15 @@
 
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.geometry.Rectangle;
+import org.opensearch.search.aggregations.bucket.GeoTileUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.MAX_ZOOM;
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.checkPrecisionRange;
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.hashToGeoPoint;
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.keyToGeoPoint;
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.longEncode;
-import static org.opensearch.search.aggregations.bucket.geogrid.GeoTileUtils.stringEncode;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.MAX_ZOOM;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.checkPrecisionRange;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.hashToGeoPoint;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.keyToGeoPoint;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.longEncode;
+import static org.opensearch.search.aggregations.bucket.GeoTileUtils.stringEncode;
 import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.closeTo;
 import static org.hamcrest.Matchers.containsString;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorTests.java
index 0f49e02febabe..37cd7a42c7cdf 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/AutoDateHistogramAggregatorTests.java
@@ -39,12 +39,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -305,7 +305,7 @@ public void testAsSubAggWithIncreasedRounding() throws IOException {
             int n = 0;
             for (long d = start; d < end; d += anHour) {
                 docs.add(
-                    org.opensearch.common.collect.List.of(
+                    List.of(
                         new SortedNumericDocValuesField(AGGREGABLE_DATE, d),
                         new SortedSetDocValuesField("k1", aBytes),
                         new SortedSetDocValuesField("k1", d < useC ? bBytes : cBytes),
@@ -373,12 +373,7 @@ public void testAsSubAggInManyBuckets() throws IOException {
             List<List<IndexableField>> docs = new ArrayList<>();
             int n = 0;
             for (long d = start; d < end; d += anHour) {
-                docs.add(
-                    org.opensearch.common.collect.List.of(
-                        new SortedNumericDocValuesField(AGGREGABLE_DATE, d),
-                        new SortedNumericDocValuesField("n", n % 100)
-                    )
-                );
+                docs.add(List.of(new SortedNumericDocValuesField(AGGREGABLE_DATE, d), new SortedNumericDocValuesField("n", n % 100)));
                 n++;
             }
             /*
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTestCase.java
index ff9122aa42326..f5f4f3d4b0723 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTestCase.java
@@ -34,8 +34,8 @@
 
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.SortedSetDocValuesField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.index.mapper.DateFieldMapper;
@@ -48,6 +48,7 @@
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.List;
 import java.util.function.Consumer;
 
 public abstract class DateHistogramAggregatorTestCase extends AggregatorTestCase {
@@ -63,7 +64,7 @@ protected final <R extends InternalAggregation> void asSubAggTestCase(Aggregatio
         throws IOException {
         CheckedBiConsumer<RandomIndexWriter, DateFieldMapper.DateFieldType, IOException> buildIndex = (iw, dft) -> {
             iw.addDocument(
-                org.opensearch.common.collect.List.of(
+                List.of(
                     new SortedNumericDocValuesField(AGGREGABLE_DATE, dft.parse("2020-02-01T00:00:00Z")),
                     new SortedSetDocValuesField("k1", new BytesRef("a")),
                     new SortedSetDocValuesField("k2", new BytesRef("a")),
@@ -71,7 +72,7 @@ protected final <R extends InternalAggregation> void asSubAggTestCase(Aggregatio
                 )
             );
             iw.addDocument(
-                org.opensearch.common.collect.List.of(
+                List.of(
                     new SortedNumericDocValuesField(AGGREGABLE_DATE, dft.parse("2020-03-01T00:00:00Z")),
                     new SortedSetDocValuesField("k1", new BytesRef("a")),
                     new SortedSetDocValuesField("k2", new BytesRef("a")),
@@ -79,7 +80,7 @@ protected final <R extends InternalAggregation> void asSubAggTestCase(Aggregatio
                 )
             );
             iw.addDocument(
-                org.opensearch.common.collect.List.of(
+                List.of(
                     new SortedNumericDocValuesField(AGGREGABLE_DATE, dft.parse("2021-02-01T00:00:00Z")),
                     new SortedSetDocValuesField("k1", new BytesRef("a")),
                     new SortedSetDocValuesField("k2", new BytesRef("a")),
@@ -87,7 +88,7 @@ protected final <R extends InternalAggregation> void asSubAggTestCase(Aggregatio
                 )
             );
             iw.addDocument(
-                org.opensearch.common.collect.List.of(
+                List.of(
                     new SortedNumericDocValuesField(AGGREGABLE_DATE, dft.parse("2021-03-01T00:00:00Z")),
                     new SortedSetDocValuesField("k1", new BytesRef("a")),
                     new SortedSetDocValuesField("k2", new BytesRef("b")),
@@ -95,7 +96,7 @@ protected final <R extends InternalAggregation> void asSubAggTestCase(Aggregatio
                 )
             );
             iw.addDocument(
-                org.opensearch.common.collect.List.of(
+                List.of(
                     new SortedNumericDocValuesField(AGGREGABLE_DATE, dft.parse("2020-02-01T00:00:00Z")),
                     new SortedSetDocValuesField("k1", new BytesRef("b")),
                     new SortedSetDocValuesField("k2", new BytesRef("b")),
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
index 597175d89bcfe..4e8dc20c465a9 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.search.aggregations.AggregationBuilder;
@@ -193,14 +193,14 @@ public void testAsSubAgg() throws IOException {
             InternalDateHistogram adh = a.getAggregations().get("dh");
             assertThat(
                 adh.getBuckets().stream().map(bucket -> bucket.getKey().toString()).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of("2020-01-01T00:00Z", "2021-01-01T00:00Z"))
+                equalTo(List.of("2020-01-01T00:00Z", "2021-01-01T00:00Z"))
             );
 
             StringTerms.Bucket b = terms.getBucketByKey("b");
             InternalDateHistogram bdh = b.getAggregations().get("dh");
             assertThat(
                 bdh.getBuckets().stream().map(bucket -> bucket.getKey().toString()).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of("2020-01-01T00:00Z"))
+                equalTo(List.of("2020-01-01T00:00Z"))
             );
         });
         builder = new TermsAggregationBuilder("k2").field("k2").subAggregation(builder);
@@ -211,7 +211,7 @@ public void testAsSubAgg() throws IOException {
             InternalDateHistogram ak1adh = ak1a.getAggregations().get("dh");
             assertThat(
                 ak1adh.getBuckets().stream().map(bucket -> bucket.getKey().toString()).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of("2020-01-01T00:00Z", "2021-01-01T00:00Z"))
+                equalTo(List.of("2020-01-01T00:00Z", "2021-01-01T00:00Z"))
             );
 
             StringTerms.Bucket b = terms.getBucketByKey("b");
@@ -220,13 +220,13 @@ public void testAsSubAgg() throws IOException {
             InternalDateHistogram bk1adh = bk1a.getAggregations().get("dh");
             assertThat(
                 bk1adh.getBuckets().stream().map(bucket -> bucket.getKey().toString()).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of("2021-01-01T00:00Z"))
+                equalTo(List.of("2021-01-01T00:00Z"))
             );
             StringTerms.Bucket bk1b = bk1.getBucketByKey("b");
             InternalDateHistogram bk1bdh = bk1b.getAggregations().get("dh");
             assertThat(
                 bk1bdh.getBuckets().stream().map(bucket -> bucket.getKey().toString()).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of("2020-01-01T00:00Z"))
+                equalTo(List.of("2020-01-01T00:00Z"))
             );
         });
     }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapperTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapperTests.java
index 7679e77d35eff..e17dc371f9ee7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapperTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateIntervalWrapperTests.java
@@ -32,7 +32,7 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregatorTests.java
index 87f3ed166e5d0..08adc6e3d550a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DateRangeHistogramAggregatorTests.java
@@ -36,12 +36,12 @@
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.queries.BinaryDocValuesRangeQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.lucene.search.Queries;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBoundsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBoundsTests.java
index e1a1060590dfe..525cf0333a92a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBoundsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/DoubleBoundsTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.aggregations.bucket.histogram;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogramTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogramTests.java
index 72b11c1657fb5..99a5c6642abbb 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogramTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/InternalVariableWidthHistogramTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.aggregations.bucket.histogram;
 
 import org.apache.lucene.tests.util.TestUtil;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/LongBoundsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/LongBoundsTests.java
index d717f27d2f542..7a071abd7e380 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/LongBoundsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/LongBoundsTests.java
@@ -34,16 +34,16 @@
 
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatter;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregatorTests.java
index e7b22a9a57476..3cafa872ef443 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/NumericHistogramAggregatorTests.java
@@ -37,10 +37,10 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
@@ -303,10 +303,9 @@ public void testIncorrectFieldType() throws Exception {
             try (IndexReader reader = w.getReader()) {
                 IndexSearcher searcher = new IndexSearcher(reader);
 
-                expectThrows(
-                    IllegalArgumentException.class,
-                    () -> { searchAndReduce(searcher, new MatchAllDocsQuery(), aggBuilder, keywordField("field")); }
-                );
+                expectThrows(IllegalArgumentException.class, () -> {
+                    searchAndReduce(searcher, new MatchAllDocsQuery(), aggBuilder, keywordField("field"));
+                });
             }
         }
 
@@ -420,7 +419,7 @@ public void testAsSubAgg() throws IOException {
             List<List<IndexableField>> docs = new ArrayList<>();
             for (int n = 0; n < 10000; n++) {
                 docs.add(
-                    org.opensearch.common.collect.List.of(
+                    List.of(
                         new SortedNumericDocValuesField("outer", n % 100),
                         new SortedNumericDocValuesField("inner", n / 100),
                         new SortedNumericDocValuesField("n", n)
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregatorTests.java
index 41bd0d77bff00..b3d58d07fb41c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/RangeHistogramAggregatorTests.java
@@ -37,10 +37,10 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.network.InetAddresses;
@@ -492,14 +492,14 @@ public void testAsSubAgg() throws IOException {
             List<List<IndexableField>> docs = new ArrayList<>();
             for (int n = 0; n < 10000; n++) {
                 BytesRef outerRange = RangeType.LONG.encodeRanges(
-                    org.opensearch.common.collect.Set.of(new RangeFieldMapper.Range(RangeType.LONG, n % 100, n % 100 + 10, true, true))
+                    Set.of(new RangeFieldMapper.Range(RangeType.LONG, n % 100, n % 100 + 10, true, true))
                 );
                 BytesRef innerRange = RangeType.LONG.encodeRanges(
-                    org.opensearch.common.collect.Set.of(new RangeFieldMapper.Range(RangeType.LONG, n / 100, n / 100 + 10, true, true))
+                    Set.of(new RangeFieldMapper.Range(RangeType.LONG, n / 100, n / 100 + 10, true, true))
                 );
 
                 docs.add(
-                    org.opensearch.common.collect.List.of(
+                    List.of(
                         new BinaryDocValuesField("outer", outerRange),
                         new BinaryDocValuesField("inner", innerRange),
                         new SortedNumericDocValuesField("n", n)
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorTests.java
index b1d62f3402bc3..1922d7dcf395b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/histogram/VariableWidthHistogramAggregatorTests.java
@@ -36,11 +36,11 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
@@ -493,22 +493,12 @@ public void testAsSubAggregation() throws IOException {
         AggregationBuilder builder = new TermsAggregationBuilder("t").field("t")
             .subAggregation(new VariableWidthHistogramAggregationBuilder("v").field("v").setNumBuckets(2));
         CheckedConsumer<RandomIndexWriter, IOException> buildIndex = iw -> {
-            iw.addDocument(
-                org.opensearch.common.collect.List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 1))
-            );
-            iw.addDocument(
-                org.opensearch.common.collect.List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 10))
-            );
-            iw.addDocument(
-                org.opensearch.common.collect.List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 11))
-            );
+            iw.addDocument(List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 1)));
+            iw.addDocument(List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 10)));
+            iw.addDocument(List.of(new SortedNumericDocValuesField("t", 1), new SortedNumericDocValuesField("v", 11)));
 
-            iw.addDocument(
-                org.opensearch.common.collect.List.of(new SortedNumericDocValuesField("t", 2), new SortedNumericDocValuesField("v", 20))
-            );
-            iw.addDocument(
-                org.opensearch.common.collect.List.of(new SortedNumericDocValuesField("t", 2), new SortedNumericDocValuesField("v", 30))
-            );
+            iw.addDocument(List.of(new SortedNumericDocValuesField("t", 2), new SortedNumericDocValuesField("v", 20)));
+            iw.addDocument(List.of(new SortedNumericDocValuesField("t", 2), new SortedNumericDocValuesField("v", 30)));
         };
         Consumer<LongTerms> verify = terms -> {
             /*
@@ -520,14 +510,14 @@ public void testAsSubAggregation() throws IOException {
             InternalVariableWidthHistogram v1 = t1.getAggregations().get("v");
             assertThat(
                 v1.getBuckets().stream().map(InternalVariableWidthHistogram.Bucket::centroid).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of(1.0, 10.5))
+                equalTo(List.of(1.0, 10.5))
             );
 
             LongTerms.Bucket t2 = terms.getBucketByKey("1");
             InternalVariableWidthHistogram v2 = t2.getAggregations().get("v");
             assertThat(
                 v2.getBuckets().stream().map(InternalVariableWidthHistogram.Bucket::centroid).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of(20.0, 30))
+                equalTo(List.of(20.0, 30))
             );
         };
         Exception e = expectThrows(
@@ -550,10 +540,12 @@ public void testSmallShardSize() throws Exception {
             IllegalArgumentException.class,
             () -> testSearchCase(
                 DEFAULT_QUERY,
-                org.opensearch.common.collect.List.of(),
+                List.of(),
                 true,
                 aggregation -> aggregation.field(NUMERIC_FIELD).setNumBuckets(2).setShardSize(2),
-                histogram -> { fail(); }
+                histogram -> {
+                    fail();
+                }
             )
         );
         assertThat(e.getMessage(), equalTo("3/4 of shard_size must be at least buckets but was [1<2] for [_name]"));
@@ -568,7 +560,7 @@ public void testHugeShardSize() throws Exception {
             aggregation -> aggregation.field(NUMERIC_FIELD).setShardSize(1000000000),
             histogram -> assertThat(
                 histogram.getBuckets().stream().map(InternalVariableWidthHistogram.Bucket::getKey).collect(toList()),
-                equalTo(org.opensearch.common.collect.List.of(1.0, 2.0, 3.0))
+                equalTo(List.of(1.0, 2.0, 3.0))
             )
         );
     }
@@ -578,10 +570,12 @@ public void testSmallInitialBuffer() throws Exception {
             IllegalArgumentException.class,
             () -> testSearchCase(
                 DEFAULT_QUERY,
-                org.opensearch.common.collect.List.of(),
+                List.of(),
                 true,
                 aggregation -> aggregation.field(NUMERIC_FIELD).setInitialBuffer(1),
-                histogram -> { fail(); }
+                histogram -> {
+                    fail();
+                }
             )
         );
         assertThat(e.getMessage(), equalTo("initial_buffer must be at least buckets but was [1<10] for [_name]"));
@@ -597,7 +591,7 @@ public void testOutOfOrderInitialBuffer() throws Exception {
             histogram -> {
                 assertThat(
                     histogram.getBuckets().stream().map(InternalVariableWidthHistogram.Bucket::getKey).collect(toList()),
-                    equalTo(org.opensearch.common.collect.List.of(1.0, 2.0, 3.0))
+                    equalTo(List.of(1.0, 2.0, 3.0))
                 );
             }
         );
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorTests.java
index e888972b8e447..b530dc31d30ed 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/missing/MissingAggregatorTests.java
@@ -37,10 +37,10 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.settings.Settings;
@@ -120,7 +120,7 @@ public void testMatchAllDocs() throws IOException {
         }, internalMissing -> {
             assertEquals(numDocs, internalMissing.getDocCount());
             assertTrue(AggregationInspectionHelper.hasValue(internalMissing));
-        }, org.opensearch.common.collect.List.of(aggFieldType, anotherFieldType));
+        }, List.of(aggFieldType, anotherFieldType));
     }
 
     public void testMatchSparse() throws IOException {
@@ -145,7 +145,7 @@ public void testMatchSparse() throws IOException {
         testCase(newMatchAllQuery(), builder, writer -> writer.addDocuments(docs), internalMissing -> {
             assertEquals(finalDocsMissingAggField, internalMissing.getDocCount());
             assertTrue(AggregationInspectionHelper.hasValue(internalMissing));
-        }, org.opensearch.common.collect.List.of(aggFieldType, anotherFieldType));
+        }, List.of(aggFieldType, anotherFieldType));
     }
 
     public void testMatchSparseRangeField() throws IOException {
@@ -225,7 +225,7 @@ public void testMissingParam() throws IOException {
         }, internalMissing -> {
             assertEquals(0, internalMissing.getDocCount());
             assertFalse(AggregationInspectionHelper.hasValue(internalMissing));
-        }, org.opensearch.common.collect.List.of(aggFieldType, anotherFieldType));
+        }, List.of(aggFieldType, anotherFieldType));
     }
 
     public void testMultiValuedField() throws IOException {
@@ -241,7 +241,7 @@ public void testMultiValuedField() throws IOException {
             if (randomBoolean()) {
                 final long randomLong = randomLong();
                 docs.add(
-                    org.opensearch.common.collect.Set.of(
+                    Set.of(
                         new SortedNumericDocValuesField(aggFieldType.name(), randomLong),
                         new SortedNumericDocValuesField(aggFieldType.name(), randomLong + 1)
                     )
@@ -256,7 +256,7 @@ public void testMultiValuedField() throws IOException {
         testCase(newMatchAllQuery(), builder, writer -> writer.addDocuments(docs), internalMissing -> {
             assertEquals(finalDocsMissingAggField, internalMissing.getDocCount());
             assertTrue(AggregationInspectionHelper.hasValue(internalMissing));
-        }, org.opensearch.common.collect.List.of(aggFieldType, anotherFieldType));
+        }, List.of(aggFieldType, anotherFieldType));
     }
 
     public void testSingleValuedFieldWithValueScript() throws IOException {
@@ -289,12 +289,12 @@ private void valueScriptTestCase(Script script) throws IOException {
         testCase(newMatchAllQuery(), builder, writer -> writer.addDocuments(docs), internalMissing -> {
             assertEquals(finalDocsMissingField, internalMissing.getDocCount());
             assertTrue(AggregationInspectionHelper.hasValue(internalMissing));
-        }, org.opensearch.common.collect.List.of(aggFieldType, anotherFieldType));
+        }, List.of(aggFieldType, anotherFieldType));
     }
 
     public void testMultiValuedFieldWithFieldScriptWithParams() throws IOException {
         final long threshold = 10;
-        final Map<String, Object> params = org.opensearch.common.collect.Map.of("field", "agg_field", "threshold", threshold);
+        final Map<String, Object> params = Map.of("field", "agg_field", "threshold", threshold);
         fieldScriptTestCase(new Script(ScriptType.INLINE, MockScriptEngine.NAME, FIELD_SCRIPT_PARAMS, params), threshold);
     }
 
@@ -320,7 +320,7 @@ private void fieldScriptTestCase(Script script, long threshold) throws IOExcepti
                 docsBelowThreshold++;
             }
             docs.add(
-                org.opensearch.common.collect.Set.of(
+                Set.of(
                     new SortedNumericDocValuesField(aggFieldType.name(), firstValue),
                     new SortedNumericDocValuesField(aggFieldType.name(), secondValue)
                 )
@@ -362,7 +362,7 @@ protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldTy
 
     @Override
     protected List<ValuesSourceType> getSupportedValuesSourceTypes() {
-        return org.opensearch.common.collect.List.of(
+        return List.of(
             CoreValuesSourceType.NUMERIC,
             CoreValuesSourceType.BYTES,
             CoreValuesSourceType.GEOPOINT,
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorTests.java
index 8ab0cc0023346..406c411494d60 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/NestedAggregatorTests.java
@@ -41,7 +41,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
@@ -49,6 +48,7 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.collect.Tuple;
@@ -57,9 +57,9 @@
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.script.MockScriptEngine;
@@ -343,15 +343,15 @@ public void testResetRootDocId() throws Exception {
                 // 1 segment with, 1 root document, with 3 nested sub docs
                 Document document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.FIELD_TYPE));
@@ -365,7 +365,7 @@ public void testResetRootDocId() throws Exception {
                 // 1 document, with 1 nested subdoc
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("2"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("2"), IdFieldMapper.Defaults.FIELD_TYPE));
@@ -376,7 +376,7 @@ public void testResetRootDocId() throws Exception {
                 // and 1 document, with 1 nested subdoc
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("3"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("3"), IdFieldMapper.Defaults.FIELD_TYPE));
@@ -613,13 +613,13 @@ public void testPreGetChildLeafCollectors() throws IOException {
                 List<Document> documents = new ArrayList<>();
                 Document document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key1")));
                 document.add(new SortedDocValuesField("value", new BytesRef("a1")));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("1"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key2")));
                 document.add(new SortedDocValuesField("value", new BytesRef("b1")));
                 documents.add(document);
@@ -633,13 +633,13 @@ public void testPreGetChildLeafCollectors() throws IOException {
 
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("2"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key1")));
                 document.add(new SortedDocValuesField("value", new BytesRef("a2")));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("2"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key2")));
                 document.add(new SortedDocValuesField("value", new BytesRef("b2")));
                 documents.add(document);
@@ -653,13 +653,13 @@ public void testPreGetChildLeafCollectors() throws IOException {
 
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("3"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key1")));
                 document.add(new SortedDocValuesField("value", new BytesRef("a3")));
                 documents.add(document);
                 document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId("3"), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(new SortedDocValuesField("key", new BytesRef("key2")));
                 document.add(new SortedDocValuesField("value", new BytesRef("b3")));
                 documents.add(document);
@@ -863,7 +863,7 @@ public static CheckedConsumer<RandomIndexWriter, IOException> buildResellerData(
                 }
                 Document document = new Document();
                 document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(p)), IdFieldMapper.Defaults.FIELD_TYPE));
-                document.add(new Field(TypeFieldMapper.NAME, "__nested_field", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                document.add(new Field(NestedPathFieldMapper.NAME, "nested_field", NestedPathFieldMapper.Defaults.FIELD_TYPE));
                 document.add(sequenceIDFields.primaryTerm);
                 document.add(new SortedNumericDocValuesField("product_id", p));
                 documents.add(document);
@@ -891,7 +891,7 @@ private static double[] generateDocuments(List<Document> documents, int numNeste
         for (int nested = 0; nested < numNestedDocs; nested++) {
             Document document = new Document();
             document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(id)), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-            document.add(new Field(TypeFieldMapper.NAME, "__" + path, TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+            document.add(new Field(NestedPathFieldMapper.NAME, path, NestedPathFieldMapper.Defaults.FIELD_TYPE));
             long value = randomNonNegativeLong() % 10000;
             document.add(new SortedNumericDocValuesField(fieldName, value));
             documents.add(document);
@@ -906,7 +906,7 @@ private List<Document> generateBook(String id, String[] authors, int[] numPages)
         for (int numPage : numPages) {
             Document document = new Document();
             document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(id), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-            document.add(new Field(TypeFieldMapper.NAME, "__nested_chapters", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+            document.add(new Field(NestedPathFieldMapper.NAME, "nested_chapters", NestedPathFieldMapper.Defaults.FIELD_TYPE));
             document.add(new SortedNumericDocValuesField("num_pages", numPage));
             documents.add(document);
         }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorTests.java
index cf0e31bc63467..a0efe2bffc64c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/nested/ReverseNestedAggregatorTests.java
@@ -37,14 +37,14 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.AggregatorTestCase;
@@ -133,7 +133,7 @@ public void testMaxFromParentDocs() throws IOException {
                         document.add(
                             new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(i)), IdFieldMapper.Defaults.NESTED_FIELD_TYPE)
                         );
-                        document.add(new Field(TypeFieldMapper.NAME, "__" + NESTED_OBJECT, TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                        document.add(new Field(NestedPathFieldMapper.NAME, NESTED_OBJECT, NestedPathFieldMapper.Defaults.FIELD_TYPE));
                         documents.add(document);
                         expectedNestedDocs++;
                     }
@@ -193,7 +193,7 @@ public void testFieldAlias() throws IOException {
                         document.add(
                             new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(i)), IdFieldMapper.Defaults.NESTED_FIELD_TYPE)
                         );
-                        document.add(new Field(TypeFieldMapper.NAME, "__" + NESTED_OBJECT, TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                        document.add(new Field(NestedPathFieldMapper.NAME, NESTED_OBJECT, NestedPathFieldMapper.Defaults.FIELD_TYPE));
                         documents.add(document);
                     }
                     Document document = new Document();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorTests.java
index 9c2578a2378cc..77e59375ef012 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/BinaryRangeAggregatorTests.java
@@ -31,13 +31,8 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import java.io.IOException;
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Set;
-
-import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.fielddata.AbstractSortedSetDocValues;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
 import org.opensearch.search.aggregations.LeafBucketCollector;
@@ -45,7 +40,10 @@
 import org.opensearch.search.aggregations.bucket.range.BinaryRangeAggregator.SortedSetRangeLeafCollector;
 import org.opensearch.test.OpenSearchTestCase;
 
-import com.carrotsearch.hppc.LongHashSet;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
 
 public class BinaryRangeAggregatorTests extends OpenSearchTestCase {
 
@@ -83,6 +81,10 @@ public long getValueCount() {
             return terms.length;
         }
 
+        @Override
+        public int docValueCount() {
+            return ords.length;
+        }
     }
 
     private void doTestSortedSetRangeLeafCollector(int maxNumValuesPerDoc) throws Exception {
@@ -117,12 +119,12 @@ protected void doCollect(LeafBucketCollector sub, int doc, long bucket) throws I
         final int[] expectedCounts = new int[ranges.length];
         final int maxDoc = randomIntBetween(5, 10);
         for (int doc = 0; doc < maxDoc; ++doc) {
-            LongHashSet ordinalSet = new LongHashSet();
+            Set<Long> ordinalSet = new HashSet<>();
             final int numValues = randomInt(maxNumValuesPerDoc);
             while (ordinalSet.size() < numValues) {
-                ordinalSet.add(random().nextInt(terms.length));
+                ordinalSet.add(TestUtil.nextLong(random(), 0, terms.length - 1));
             }
-            final long[] ords = ordinalSet.toArray();
+            final long[] ords = ordinalSet.stream().mapToLong(Long::longValue).toArray();
             Arrays.sort(ords);
             values.ords = ords;
 
@@ -218,12 +220,12 @@ protected void doCollect(LeafBucketCollector sub, int doc, long bucket) throws I
         final int[] expectedCounts = new int[ranges.length];
         final int maxDoc = randomIntBetween(5, 10);
         for (int doc = 0; doc < maxDoc; ++doc) {
-            LongHashSet ordinalSet = new LongHashSet();
+            Set<Long> ordinalSet = new HashSet<>();
             final int numValues = randomInt(maxNumValuesPerDoc);
             while (ordinalSet.size() < numValues) {
-                ordinalSet.add(random().nextInt(terms.length));
+                ordinalSet.add(TestUtil.nextLong(random(), 0, terms.length - 1));
             }
-            final long[] ords = ordinalSet.toArray();
+            final long[] ords = ordinalSet.stream().mapToLong(Long::longValue).toArray();
             Arrays.sort(ords);
             values.ords = ords;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorTests.java
index e6d7230aa6cb0..26ccc1075220b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/DateRangeAggregatorTests.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.CheckedConsumer;
@@ -220,13 +220,9 @@ public void testKeywordField() {
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> testCase(
-                aggregationBuilder,
-                new MatchAllDocsQuery(),
-                iw -> { iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo")))); },
-                range -> fail("Should have thrown exception"),
-                fieldType
-            )
+            () -> testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+                iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo"))));
+            }, range -> fail("Should have thrown exception"), fieldType)
         );
         assertEquals("Field [not_a_number] of type [keyword] is not supported for aggregation [date_range]", e.getMessage());
     }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorTests.java
index b74f21ef09037..b57295431d678 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/IpRangeAggregatorTests.java
@@ -35,10 +35,10 @@
 import org.apache.lucene.document.InetAddressPoint;
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.network.NetworkAddress;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilderTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilderTests.java
index ef5af0b496113..4362ce48003cc 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregationBuilderTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.bucket.range;
 
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -128,6 +128,6 @@ public void testNumericKeys() throws IOException {
         );
         assertThat(builder.getName(), equalTo("test"));
         assertThat(builder.field(), equalTo("f"));
-        assertThat(builder.ranges, equalTo(org.opensearch.common.collect.List.of(new RangeAggregator.Range("1", null, 0d))));
+        assertThat(builder.ranges, equalTo(List.of(new RangeAggregator.Range("1", null, 0d))));
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorTests.java
index f1be4d1ede930..761615ad1d7eb 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/range/RangeAggregatorTests.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.DateFieldMapper;
@@ -245,13 +245,9 @@ public void testUnsupportedType() {
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> testCase(
-                aggregationBuilder,
-                new MatchAllDocsQuery(),
-                iw -> { iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo")))); },
-                range -> fail("Should have thrown exception"),
-                fieldType
-            )
+            () -> testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+                iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo"))));
+            }, range -> fail("Should have thrown exception"), fieldType)
         );
         assertEquals("Field [not_a_number] of type [keyword] is not supported for aggregation [range]", e.getMessage());
     }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollectorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollectorTests.java
index 427d0b89aa688..67f7f70b88e7e 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollectorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/BestDocsDeferringCollectorTests.java
@@ -37,7 +37,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.ScoreDoc;
@@ -45,10 +44,11 @@
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.AggregatorTestCase;
 import org.opensearch.search.aggregations.BucketCollector;
 import org.opensearch.search.aggregations.LeafBucketCollector;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedSamplerTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedSamplerTests.java
index bb07b9c4af37e..1e1dee7ab16f6 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedSamplerTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/sampler/DiversifiedSamplerTests.java
@@ -40,10 +40,10 @@
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
 import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BinaryTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BinaryTermsAggregatorTests.java
index 7703afa88d93c..4f20649ad566b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BinaryTermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BinaryTermsAggregatorTests.java
@@ -34,14 +34,13 @@
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.automaton.RegExp;
 import org.opensearch.common.Numbers;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -97,7 +96,7 @@ public void testMatchAllDocs() throws IOException {
     }
 
     public void testBadIncludeExclude() throws IOException {
-        IncludeExclude includeExclude = new IncludeExclude(new RegExp("foo"), null);
+        IncludeExclude includeExclude = new IncludeExclude("foo", null);
 
         // Make sure the include/exclude fails regardless of how the user tries to type hint the agg
         AggregationExecutionException e = expectThrows(
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrdsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrdsTests.java
index f73146038a5f1..c593ed4147e7e 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrdsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/BytesKeyedBucketOrdsTests.java
@@ -36,7 +36,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/DoubleTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/DoubleTermsTests.java
index 853d56202c360..5fe9c1dee358d 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/DoubleTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/DoubleTermsTests.java
@@ -59,6 +59,12 @@ public class DoubleTermsTests extends InternalTermsTestCase {
         long minDocCount = 1;
         int requiredSize = 3;
         int shardSize = requiredSize + 2;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+            minDocCount,
+            0,
+            requiredSize,
+            shardSize
+        );
         DocValueFormat format = randomNumericDocValueFormat();
         long otherDocCount = 0;
         List<DoubleTerms.Bucket> buckets = new ArrayList<>();
@@ -75,15 +81,14 @@ public class DoubleTermsTests extends InternalTermsTestCase {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -158,15 +163,14 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 name,
                 doubleTerms.reduceOrder,
                 order,
-                requiredSize,
-                minDocCount,
                 metadata,
                 format,
                 shardSize,
                 showTermDocCountError,
                 otherDocCount,
                 buckets,
-                docCountError
+                docCountError,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, shardSize)
             );
         } else {
             String name = instance.getName();
@@ -195,7 +199,7 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 default:
                     throw new AssertionError("Illegal randomisation branch");
             }
-            return new UnmappedTerms(name, order, requiredSize, minDocCount, metadata);
+            return new UnmappedTerms(name, order, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTermsTests.java
new file mode 100644
index 0000000000000..9f8bab1179ad6
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalMultiTermsTests.java
@@ -0,0 +1,121 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.apache.lucene.document.InetAddressPoint;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
+import org.opensearch.search.aggregations.support.CoreValuesSourceType;
+import org.opensearch.search.aggregations.support.ValuesSourceType;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.asList;
+
+public class InternalMultiTermsTests extends InternalTermsTestCase {
+
+    /**
+     * terms count and type should consistent across entire test.
+     */
+    private final List<ValuesSourceType> types = getSupportedValuesSourceTypes();
+
+    @Override
+    protected InternalTerms<?, ?> createTestInstance(
+        String name,
+        Map<String, Object> metadata,
+        InternalAggregations aggregations,
+        boolean showTermDocCountError,
+        long docCountError
+    ) {
+        BucketOrder order = BucketOrder.count(false);
+        long minDocCount = 1;
+        int requiredSize = 3;
+        int shardSize = requiredSize + 2;
+        long otherDocCount = 0;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+            minDocCount,
+            0,
+            requiredSize,
+            shardSize
+        );
+
+        final int numBuckets = randomNumberOfBuckets();
+
+        List<InternalMultiTerms.Bucket> buckets = new ArrayList<>();
+        List<DocValueFormat> formats = types.stream().map(type -> type.getFormatter(null, null)).collect(Collectors.toList());
+
+        for (int i = 0; i < numBuckets; i++) {
+            buckets.add(
+                new InternalMultiTerms.Bucket(
+                    types.stream().map(this::value).collect(Collectors.toList()),
+                    minDocCount,
+                    aggregations,
+                    showTermDocCountError,
+                    docCountError,
+                    formats
+                )
+            );
+        }
+        BucketOrder reduceOrder = rarely() ? order : BucketOrder.key(true);
+        // mimic per-shard bucket sort operation, which is required by bucket reduce phase.
+        Collections.sort(buckets, reduceOrder.comparator());
+        return new InternalMultiTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            docCountError,
+            formats,
+            buckets,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
+        return ParsedMultiTerms.class;
+    }
+
+    private static List<ValuesSourceType> getSupportedValuesSourceTypes() {
+        return Collections.unmodifiableList(
+            asList(
+                CoreValuesSourceType.NUMERIC,
+                CoreValuesSourceType.BYTES,
+                CoreValuesSourceType.IP,
+                CoreValuesSourceType.DATE,
+                CoreValuesSourceType.BOOLEAN
+            )
+        );
+    }
+
+    private Object value(ValuesSourceType type) {
+        if (CoreValuesSourceType.NUMERIC.equals(type)) {
+            return randomInt();
+        } else if (CoreValuesSourceType.DATE.equals(type)) {
+            return randomNonNegativeLong();
+        } else if (CoreValuesSourceType.BOOLEAN.equals(type)) {
+            return randomBoolean();
+        } else if (CoreValuesSourceType.BYTES.equals(type)) {
+            return new BytesRef(randomAlphaOfLength(10));
+        } else if (CoreValuesSourceType.IP.equals(type)) {
+            return new BytesRef(InetAddressPoint.encode(randomIp(randomBoolean())));
+        }
+        throw new IllegalArgumentException("unexpected type [" + type.typeName() + "]");
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTermsTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTermsTestCase.java
index aab9e91576b18..e640aa92ac782 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTermsTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalSignificantTermsTestCase.java
@@ -114,7 +114,7 @@ protected abstract InternalSignificantTerms createTestInstance(
     @Override
     protected InternalSignificantTerms createUnmappedInstance(String name, Map<String, Object> metadata) {
         InternalSignificantTerms<?, ?> testInstance = createTestInstance(name, metadata);
-        return new UnmappedSignificantTerms(name, testInstance.requiredSize, testInstance.minDocCount, metadata);
+        return new UnmappedSignificantTerms(name, testInstance.bucketCountThresholds, metadata);
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalTermsTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalTermsTestCase.java
index d3f7c62021243..2e00248a70771 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalTermsTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/InternalTermsTestCase.java
@@ -73,7 +73,7 @@ public void init() {
     @Override
     protected InternalTerms<?, ?> createUnmappedInstance(String name, Map<String, Object> metadata) {
         InternalTerms<?, ?> testInstance = createTestInstance(name, metadata);
-        return new UnmappedTerms(name, testInstance.order, testInstance.requiredSize, testInstance.minDocCount, metadata);
+        return new UnmappedTerms(name, testInstance.order, testInstance.bucketCountThresholds, metadata);
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/KeywordTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/KeywordTermsAggregatorTests.java
index 05197c7e85844..4229361aa7f46 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/KeywordTermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/KeywordTermsAggregatorTests.java
@@ -35,12 +35,12 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrdsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrdsTests.java
index d0a6500ecf9e7..bdecae8f7dfa3 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrdsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongKeyedBucketOrdsTests.java
@@ -35,7 +35,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.CardinalityUpperBound;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongTermsTests.java
index becf89c4603f3..44fa9f5e79593 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/LongTermsTests.java
@@ -59,6 +59,12 @@ public class LongTermsTests extends InternalTermsTestCase {
         long minDocCount = 1;
         int requiredSize = 3;
         int shardSize = requiredSize + 2;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+            minDocCount,
+            0,
+            requiredSize,
+            shardSize
+        );
         DocValueFormat format = randomNumericDocValueFormat();
         long otherDocCount = 0;
         List<LongTerms.Bucket> buckets = new ArrayList<>();
@@ -75,15 +81,14 @@ public class LongTermsTests extends InternalTermsTestCase {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 
@@ -158,15 +163,14 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 name,
                 longTerms.reduceOrder,
                 order,
-                requiredSize,
-                minDocCount,
                 metadata,
                 format,
                 shardSize,
                 showTermDocCountError,
                 otherDocCount,
                 buckets,
-                docCountError
+                docCountError,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, shardSize)
             );
         } else {
             String name = instance.getName();
@@ -195,7 +199,7 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 default:
                     throw new AssertionError("Illegal randomisation branch");
             }
-            return new UnmappedTerms(name, order, requiredSize, minDocCount, metadata);
+            return new UnmappedTerms(name, order, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilderTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilderTests.java
new file mode 100644
index 0000000000000..c0b2b55fefeda
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregationBuilderTests.java
@@ -0,0 +1,181 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.BaseAggregationTestCase;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValueType;
+
+import java.time.ZoneId;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Supplier;
+
+public class MultiTermsAggregationBuilderTests extends BaseAggregationTestCase<MultiTermsAggregationBuilder> {
+
+    @Override
+    protected MultiTermsAggregationBuilder createTestAggregatorBuilder() {
+        String name = randomAlphaOfLengthBetween(3, 20);
+        MultiTermsAggregationBuilder factory = new MultiTermsAggregationBuilder(name);
+
+        int termsCount = randomIntBetween(2, 10);
+        List<MultiTermsValuesSourceConfig> fieldConfigs = new ArrayList<>();
+        for (int i = 0; i < termsCount; i++) {
+            fieldConfigs.add(randomFieldConfig());
+        }
+        factory.terms(fieldConfigs);
+
+        if (randomBoolean()) {
+            factory.size(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.shardSize(randomIntBetween(1, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            int minDocCount = randomInt(4);
+            switch (minDocCount) {
+                case 0:
+                    break;
+                case 1:
+                case 2:
+                case 3:
+                case 4:
+                    minDocCount = randomIntBetween(0, Integer.MAX_VALUE);
+                    break;
+                default:
+                    fail();
+            }
+            factory.minDocCount(minDocCount);
+        }
+        if (randomBoolean()) {
+            int shardMinDocCount = randomInt(4);
+            switch (shardMinDocCount) {
+                case 0:
+                    break;
+                case 1:
+                case 2:
+                case 3:
+                case 4:
+                    shardMinDocCount = randomIntBetween(0, Integer.MAX_VALUE);
+                    break;
+                default:
+                    fail();
+            }
+            factory.shardMinDocCount(shardMinDocCount);
+        }
+        if (randomBoolean()) {
+            factory.collectMode(randomFrom(Aggregator.SubAggCollectionMode.values()));
+        }
+        if (randomBoolean()) {
+            List<BucketOrder> order = randomOrder();
+            if (order.size() == 1 && randomBoolean()) {
+                factory.order(order.get(0));
+            } else {
+                factory.order(order);
+            }
+        }
+        if (randomBoolean()) {
+            factory.showTermDocCountError(randomBoolean());
+        }
+        return factory;
+    }
+
+    public void testInvalidTermsParams() {
+        IllegalArgumentException exception = expectThrows(IllegalArgumentException.class, () -> {
+            new MultiTermsAggregationBuilder("_name").terms(Collections.singletonList(randomFieldConfig()));
+        });
+        assertEquals(
+            "multi term aggregation must has at least 2 terms. Found [1] in [_name] Use terms aggregation for single term aggregation",
+            exception.getMessage()
+        );
+
+        exception = expectThrows(
+            IllegalArgumentException.class,
+            () -> { new MultiTermsAggregationBuilder("_name").terms(Collections.emptyList()); }
+        );
+        assertEquals("multi term aggregation must has at least 2 terms. Found [0] in [_name]", exception.getMessage());
+
+        exception = expectThrows(IllegalArgumentException.class, () -> { new MultiTermsAggregationBuilder("_name").terms(null); });
+        assertEquals("[terms] must not be null. Found null terms in [_name]", exception.getMessage());
+    }
+
+    private List<BucketOrder> randomOrder() {
+        List<BucketOrder> orders = new ArrayList<>();
+        switch (randomInt(4)) {
+            case 0:
+                orders.add(BucketOrder.key(randomBoolean()));
+                break;
+            case 1:
+                orders.add(BucketOrder.count(randomBoolean()));
+                break;
+            case 2:
+                orders.add(BucketOrder.aggregation(randomAlphaOfLengthBetween(3, 20), randomBoolean()));
+                break;
+            case 3:
+                orders.add(BucketOrder.aggregation(randomAlphaOfLengthBetween(3, 20), randomAlphaOfLengthBetween(3, 20), randomBoolean()));
+                break;
+            case 4:
+                int numOrders = randomIntBetween(1, 3);
+                for (int i = 0; i < numOrders; i++) {
+                    orders.addAll(randomOrder());
+                }
+                break;
+            default:
+                fail();
+        }
+        return orders;
+    }
+
+    protected static MultiTermsValuesSourceConfig randomFieldConfig() {
+        String field = randomAlphaOfLength(10);
+        Object missing = randomBoolean() ? randomAlphaOfLength(10) : null;
+        ZoneId timeZone = randomBoolean() ? randomZone() : null;
+        ValueType userValueTypeHint = randomBoolean()
+            ? randomFrom(ValueType.STRING, ValueType.LONG, ValueType.DOUBLE, ValueType.DATE, ValueType.IP)
+            : null;
+        String format = randomBoolean() ? randomNumericDocValueFormat().toString() : null;
+        return randomFieldOrScript(
+            new MultiTermsValuesSourceConfig.Builder().setMissing(missing)
+                .setTimeZone(timeZone)
+                .setUserValueTypeHint(userValueTypeHint)
+                .setFormat(format),
+            field
+        ).build();
+    }
+
+    protected static MultiTermsValuesSourceConfig.Builder randomFieldOrScript(MultiTermsValuesSourceConfig.Builder builder, String field) {
+        int choice = randomInt(1);
+        switch (choice) {
+            case 0:
+                builder.setFieldName(field);
+                break;
+            case 1:
+                builder.setScript(mockScript("doc[" + field + "] + 1"));
+                break;
+            default:
+                throw new AssertionError("Unknown random operation [" + choice + "]");
+        }
+        return builder;
+    }
+
+    /**
+     * @return a random {@link DocValueFormat} that can be used in aggregations which
+     * compute numbers.
+     */
+    protected static DocValueFormat randomNumericDocValueFormat() {
+        final List<Supplier<DocValueFormat>> formats = new ArrayList<>(3);
+        formats.add(() -> DocValueFormat.RAW);
+        formats.add(() -> new DocValueFormat.Decimal(randomFrom("###.##", "###,###.##")));
+        return randomFrom(formats).get();
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregatorTests.java
new file mode 100644
index 0000000000000..d550c4c354c0f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/MultiTermsAggregatorTests.java
@@ -0,0 +1,978 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.apache.lucene.document.DoubleDocValuesField;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.FloatDocValuesField;
+import org.apache.lucene.document.InetAddressPoint;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.document.SortedSetDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.network.InetAddresses;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.time.DateFormatter;
+import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.index.IndexService;
+import org.opensearch.index.cache.IndexCache;
+import org.opensearch.index.mapper.BooleanFieldMapper;
+import org.opensearch.index.mapper.DateFieldMapper;
+import org.opensearch.index.mapper.GeoPointFieldMapper;
+import org.opensearch.index.mapper.IpFieldMapper;
+import org.opensearch.index.mapper.KeywordFieldMapper;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.script.MockScriptEngine;
+import org.opensearch.script.Script;
+import org.opensearch.script.ScriptEngine;
+import org.opensearch.script.ScriptModule;
+import org.opensearch.script.ScriptService;
+import org.opensearch.script.ScriptType;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.AggregationBuilder;
+import org.opensearch.search.aggregations.Aggregator;
+import org.opensearch.search.aggregations.AggregatorFactories;
+import org.opensearch.search.aggregations.AggregatorTestCase;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.CardinalityUpperBound;
+import org.opensearch.search.aggregations.InternalAggregation;
+import org.opensearch.search.aggregations.metrics.InternalMax;
+import org.opensearch.search.aggregations.metrics.MaxAggregationBuilder;
+import org.opensearch.search.aggregations.support.CoreValuesSourceType;
+import org.opensearch.search.aggregations.support.MultiTermsValuesSourceConfig;
+import org.opensearch.search.aggregations.support.ValueType;
+import org.opensearch.search.aggregations.support.ValuesSourceType;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.lookup.LeafDocLookup;
+import org.opensearch.test.TestSearchContext;
+import org.hamcrest.MatcherAssert;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
+import static java.util.stream.Collectors.toList;
+import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class MultiTermsAggregatorTests extends AggregatorTestCase {
+    private static final String FIELD_NAME = "field";
+    private static final String VALUE_SCRIPT_NAME = "value_script";
+    private static final String FIELD_SCRIPT_NAME = "field_script";
+
+    private static final String AGG_NAME = "_name";
+
+    private static final String INT_FIELD = "int";
+    private static final String LONG_FIELD = "long";
+    private static final String FLOAT_FIELD = "float";
+    private static final String DOUBLE_FIELD = "double";
+    private static final String KEYWORD_FIELD = "keyword";
+    private static final String DATE_FIELD = "date";
+    private static final String IP_FIELD = "ip";
+    private static final String GEO_POINT_FIELD = "geopoint";
+    private static final String BOOL_FIELD = "bool";
+    private static final String UNRELATED_KEYWORD_FIELD = "unrelated";
+
+    private static final Map<String, MappedFieldType> mappedFieldTypeMap = new HashMap<String, MappedFieldType>() {
+        {
+            put(INT_FIELD, new NumberFieldMapper.NumberFieldType(INT_FIELD, NumberFieldMapper.NumberType.INTEGER));
+            put(LONG_FIELD, new NumberFieldMapper.NumberFieldType(LONG_FIELD, NumberFieldMapper.NumberType.LONG));
+            put(FLOAT_FIELD, new NumberFieldMapper.NumberFieldType(FLOAT_FIELD, NumberFieldMapper.NumberType.FLOAT));
+            put(DOUBLE_FIELD, new NumberFieldMapper.NumberFieldType(DOUBLE_FIELD, NumberFieldMapper.NumberType.DOUBLE));
+            put(DATE_FIELD, dateFieldType(DATE_FIELD));
+            put(KEYWORD_FIELD, new KeywordFieldMapper.KeywordFieldType(KEYWORD_FIELD));
+            put(IP_FIELD, new IpFieldMapper.IpFieldType(IP_FIELD));
+            put(FIELD_NAME, new NumberFieldMapper.NumberFieldType(FIELD_NAME, NumberFieldMapper.NumberType.INTEGER));
+            put(UNRELATED_KEYWORD_FIELD, new KeywordFieldMapper.KeywordFieldType(UNRELATED_KEYWORD_FIELD));
+            put(GEO_POINT_FIELD, new GeoPointFieldMapper.GeoPointFieldType(GEO_POINT_FIELD));
+            put(BOOL_FIELD, new BooleanFieldMapper.BooleanFieldType(BOOL_FIELD));
+        }
+    };
+
+    private static final Consumer<MultiTermsAggregationBuilder> NONE_DECORATOR = null;
+
+    @Override
+    protected List<ValuesSourceType> getSupportedValuesSourceTypes() {
+        return Collections.unmodifiableList(
+            asList(
+                CoreValuesSourceType.NUMERIC,
+                CoreValuesSourceType.BYTES,
+                CoreValuesSourceType.IP,
+                CoreValuesSourceType.DATE,
+                CoreValuesSourceType.BOOLEAN
+            )
+        );
+    }
+
+    @Override
+    protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldType, String fieldName) {
+        return createTestAggregatorBuilder(asList(term(fieldName), term(fieldName)));
+    }
+
+    @Override
+    protected ScriptService getMockScriptService() {
+        final Map<String, Function<Map<String, Object>, Object>> scripts = Map.of(
+            VALUE_SCRIPT_NAME,
+            vars -> ((Number) vars.get("_value")).doubleValue() + 1,
+            FIELD_SCRIPT_NAME,
+            vars -> {
+                final String fieldName = (String) vars.get(FIELD_NAME);
+                final LeafDocLookup lookup = (LeafDocLookup) vars.get("doc");
+                return lookup.get(fieldName).stream().map(value -> ((Number) value).longValue() + 1).collect(toList());
+            }
+        );
+        final MockScriptEngine engine = new MockScriptEngine(MockScriptEngine.NAME, scripts, emptyMap());
+        final Map<String, ScriptEngine> engines = singletonMap(engine.getType(), engine);
+        return new ScriptService(Settings.EMPTY, engines, ScriptModule.CORE_CONTEXTS);
+    }
+
+    public void testNumbers() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            fieldConfigs(asList(INT_FIELD, LONG_FIELD, FLOAT_FIELD, DOUBLE_FIELD)),
+            NONE_DECORATOR,
+            iw -> {
+                iw.addDocument(
+                    asList(
+                        new NumericDocValuesField(INT_FIELD, 1),
+                        new SortedNumericDocValuesField(LONG_FIELD, 1L),
+                        new FloatDocValuesField(FLOAT_FIELD, 1.0f),
+                        new DoubleDocValuesField(DOUBLE_FIELD, 1.0d)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new NumericDocValuesField(INT_FIELD, 1),
+                        new SortedNumericDocValuesField(LONG_FIELD, 1L),
+                        new FloatDocValuesField(FLOAT_FIELD, 1.0f),
+                        new DoubleDocValuesField(DOUBLE_FIELD, 1.0d)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new NumericDocValuesField(INT_FIELD, 2),
+                        new SortedNumericDocValuesField(LONG_FIELD, 2L),
+                        new FloatDocValuesField(FLOAT_FIELD, 2.0f),
+                        new DoubleDocValuesField(DOUBLE_FIELD, 2.0d)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new NumericDocValuesField(INT_FIELD, 2),
+                        new SortedNumericDocValuesField(LONG_FIELD, 2L),
+                        new FloatDocValuesField(FLOAT_FIELD, 3.0f),
+                        new DoubleDocValuesField(DOUBLE_FIELD, 3.0d)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new NumericDocValuesField(INT_FIELD, 2),
+                        new SortedNumericDocValuesField(LONG_FIELD, 2L),
+                        new FloatDocValuesField(FLOAT_FIELD, 3.0f),
+                        new DoubleDocValuesField(DOUBLE_FIELD, 3.0d)
+                    )
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo(1L), equalTo(1L), equalTo(1.0), equalTo(1.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo(2L), equalTo(2L), equalTo(3.0), equalTo(3.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo(2L), equalTo(2L), equalTo(2.0), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testMixNumberAndKeywordWithFilter() throws IOException {
+        testAggregation(
+            new TermQuery(new Term(KEYWORD_FIELD, "a")),
+            fieldConfigs(asList(KEYWORD_FIELD, FLOAT_FIELD)),
+            NONE_DECORATOR,
+            iw -> {
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                        new StringField(KEYWORD_FIELD, "a", Field.Store.NO),
+                        new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                        new StringField(KEYWORD_FIELD, "a", Field.Store.NO),
+                        new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                        new StringField(KEYWORD_FIELD, "b", Field.Store.NO),
+                        new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                        new StringField(KEYWORD_FIELD, "a", Field.Store.NO),
+                        new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                    )
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(2));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(1.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testMixNumberAndKeyword() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD, FLOAT_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")),
+                    new NumericDocValuesField(INT_FIELD, 2),
+                    new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                )
+            );
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L), equalTo(1.0)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("b"), equalTo(1L), equalTo(2.0)));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo(2L), equalTo(2.0)));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+        });
+    }
+
+    public void testMultiValuesField() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new SortedNumericDocValuesField(INT_FIELD, 1)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedNumericDocValuesField(INT_FIELD, 1),
+                    new SortedNumericDocValuesField(INT_FIELD, 3)
+                )
+            );
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(3L)));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("b"), equalTo(1L)));
+        });
+
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new SortedNumericDocValuesField(INT_FIELD, 1),
+                    new SortedNumericDocValuesField(INT_FIELD, 2)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedSetDocValuesField(KEYWORD_FIELD, new BytesRef("c")),
+                    new SortedNumericDocValuesField(INT_FIELD, 1),
+                    new SortedNumericDocValuesField(INT_FIELD, 3)
+                )
+            );
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(7));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(2L)));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("a"), equalTo(3L)));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(3).getKey(), contains(equalTo("b"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(3).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(4).getKey(), contains(equalTo("b"), equalTo(2L)));
+            MatcherAssert.assertThat(h.getBuckets().get(4).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(5).getKey(), contains(equalTo("c"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(5).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(6).getKey(), contains(equalTo("c"), equalTo(3L)));
+            MatcherAssert.assertThat(h.getBuckets().get(6).getDocCount(), equalTo(1L));
+        });
+    }
+
+    public void testScripts() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(KEYWORD_FIELD).build(),
+                new MultiTermsValuesSourceConfig.Builder().setScript(
+                    new Script(ScriptType.INLINE, MockScriptEngine.NAME, FIELD_SCRIPT_NAME, singletonMap(FIELD_NAME, FIELD_NAME))
+                ).setUserValueTypeHint(ValueType.LONG).build()
+            ),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(FIELD_NAME, 1))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(FIELD_NAME, 3))
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("b"), equalTo(3L)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(2L)));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo(4L)));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testScriptsWithoutValueTypeHint() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(KEYWORD_FIELD).build(),
+                new MultiTermsValuesSourceConfig.Builder().setScript(
+                    new Script(ScriptType.INLINE, MockScriptEngine.NAME, FIELD_SCRIPT_NAME, singletonMap(FIELD_NAME, FIELD_NAME))
+                ).build()
+            ),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(FIELD_NAME, 1))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(FIELD_NAME, 3))
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("b"), equalTo("3")));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo("2")));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo("4")));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testValueScripts() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(KEYWORD_FIELD).build(),
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(FIELD_NAME)
+                    .setScript(new Script(ScriptType.INLINE, MockScriptEngine.NAME, VALUE_SCRIPT_NAME, emptyMap()))
+                    .build()
+            ),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(FIELD_NAME, 1))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(FIELD_NAME, 2))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(FIELD_NAME, 3))
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("b"), equalTo(3.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo(4.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testOrderByMetrics() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD)), b -> {
+            b.order(BucketOrder.aggregation("max", false));
+            b.subAggregation(new MaxAggregationBuilder("max").field(FLOAT_FIELD));
+        }, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new NumericDocValuesField(INT_FIELD, 2),
+                    new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")),
+                    new NumericDocValuesField(INT_FIELD, 3),
+                    new FloatDocValuesField(FLOAT_FIELD, 3.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 4.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new NumericDocValuesField(INT_FIELD, 2),
+                    new FloatDocValuesField(FLOAT_FIELD, 3.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")),
+                    new NumericDocValuesField(INT_FIELD, 3),
+                    new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                )
+            );
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(((InternalMax) (h.getBuckets().get(0).getAggregations().get("max"))).value(), closeTo(4.0f, 0.01));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("b"), equalTo(2L)));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(((InternalMax) (h.getBuckets().get(1).getAggregations().get("max"))).value(), closeTo(3.0f, 0.01));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo(3L)));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(((InternalMax) (h.getBuckets().get(2).getAggregations().get("max"))).value(), closeTo(3.0f, 0.01));
+        });
+    }
+
+    public void testNumberFieldFormat() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(term(KEYWORD_FIELD), new MultiTermsValuesSourceConfig.Builder().setFieldName(DOUBLE_FIELD).setFormat("00.00").build()),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new DoubleDocValuesField(DOUBLE_FIELD, 1.0d))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new DoubleDocValuesField(DOUBLE_FIELD, 2.0d))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new DoubleDocValuesField(DOUBLE_FIELD, 2.0d))
+                );
+                iw.addDocument(
+                    asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new DoubleDocValuesField(DOUBLE_FIELD, 1.0d))
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKeyAsString(), equalTo("a|01.00"));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKeyAsString(), equalTo("a|02.00"));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKeyAsString(), equalTo("b|02.00"));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testDates() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(new MultiTermsValuesSourceConfig.Builder().setFieldName(DATE_FIELD).build(), term(KEYWORD_FIELD)),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-22")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-21")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c"))
+                    )
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(4));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKeyAsString(), equalTo("2022-03-23|a"));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKeyAsString(), equalTo("2022-03-21|c"));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKeyAsString(), equalTo("2022-03-22|a"));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getKeyAsString(), equalTo("2022-03-23|b"));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testDatesFieldFormat() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(DATE_FIELD).setFormat("yyyy/MM/dd").build(),
+                term(KEYWORD_FIELD)
+            ),
+            null,
+            iw -> {
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-22")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-23")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a"))
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedNumericDocValuesField(DATE_FIELD, dateFieldType(DATE_FIELD).parse("2022-03-21")),
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c"))
+                    )
+                );
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(4));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKeyAsString(), equalTo("2022/03/23|a"));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKeyAsString(), equalTo("2022/03/21|c"));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKeyAsString(), equalTo("2022/03/22|a"));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getKeyAsString(), equalTo("2022/03/23|b"));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testIpAndKeyword() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, IP_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedDocValuesField(IP_FIELD, new BytesRef(InetAddressPoint.encode(InetAddresses.forString("192.168.0.0"))))
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                    new SortedDocValuesField(IP_FIELD, new BytesRef(InetAddressPoint.encode(InetAddresses.forString("192.168.0.1"))))
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")),
+                    new SortedDocValuesField(IP_FIELD, new BytesRef(InetAddressPoint.encode(InetAddresses.forString("192.168.0.2"))))
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new SortedDocValuesField(IP_FIELD, new BytesRef(InetAddressPoint.encode(InetAddresses.forString("192.168.0.0"))))
+                )
+            );
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(3));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo("192.168.0.0")));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKeyAsString(), equalTo("a|192.168.0.0"));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("b"), equalTo("192.168.0.1")));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKeyAsString(), equalTo("b|192.168.0.1"));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("c"), equalTo("192.168.0.2")));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKeyAsString(), equalTo("c|192.168.0.2"));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+        });
+    }
+
+    public void testEmpty() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD)), NONE_DECORATOR, iw -> {}, h -> {
+            MatcherAssert.assertThat(h.getName(), equalTo(AGG_NAME));
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(0));
+        });
+    }
+
+    public void testNull() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD, FLOAT_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                )
+            );
+            iw.addDocument(
+                asList(
+                    new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                    new NumericDocValuesField(INT_FIELD, 1),
+                    new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                )
+            );
+            iw.addDocument(asList(new NumericDocValuesField(INT_FIELD, 1), new FloatDocValuesField(FLOAT_FIELD, 2.0f)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new FloatDocValuesField(FLOAT_FIELD, 2.0f)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("d")), new NumericDocValuesField(INT_FIELD, 3)));
+
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(1));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L), equalTo(1.0)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+        });
+
+    }
+
+    public void testMissing() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(KEYWORD_FIELD).setMissing("a").build(),
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(INT_FIELD).setMissing(1).build(),
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(FLOAT_FIELD).setMissing(2.0f).build()
+            ),
+            NONE_DECORATOR,
+            iw -> {
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")),
+                        new NumericDocValuesField(INT_FIELD, 1),
+                        new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        // missing KEYWORD_FIELD
+                        new NumericDocValuesField(INT_FIELD, 1),
+                        new FloatDocValuesField(FLOAT_FIELD, 1.0f)
+                    )
+                );
+                iw.addDocument(
+                    asList(
+                        new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")),
+                        // missing INT_FIELD
+                        new FloatDocValuesField(FLOAT_FIELD, 2.0f)
+                    )
+                );
+                iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(INT_FIELD, 2)
+                // missing FLOAT_FIELD
+                ));
+                iw.addDocument(singletonList(new SortedDocValuesField(UNRELATED_KEYWORD_FIELD, new BytesRef("unrelated"))));
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(4));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(1L), equalTo(1.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("b"), equalTo(1L), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getKey(), contains(equalTo("c"), equalTo(2L), equalTo(2.0)));
+                MatcherAssert.assertThat(h.getBuckets().get(3).getDocCount(), equalTo(1L));
+            }
+        );
+    }
+
+    public void testMixKeywordAndBoolean() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, BOOL_FIELD)), NONE_DECORATOR, iw -> {
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(BOOL_FIELD, 1)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(BOOL_FIELD, 0)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(BOOL_FIELD, 0)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(BOOL_FIELD, 1)));
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(4));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(false)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKeyAsString(), equalTo("a|false"));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKey(), contains(equalTo("a"), equalTo(true)));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getKeyAsString(), equalTo("a|true"));
+            MatcherAssert.assertThat(h.getBuckets().get(1).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKey(), contains(equalTo("b"), equalTo(false)));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getKeyAsString(), equalTo("b|false"));
+            MatcherAssert.assertThat(h.getBuckets().get(2).getDocCount(), equalTo(1L));
+            MatcherAssert.assertThat(h.getBuckets().get(3).getKey(), contains(equalTo("b"), equalTo(true)));
+            MatcherAssert.assertThat(h.getBuckets().get(3).getKeyAsString(), equalTo("b|true"));
+            MatcherAssert.assertThat(h.getBuckets().get(3).getDocCount(), equalTo(1L));
+        });
+    }
+
+    public void testGeoPointField() {
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> testAggregation(
+                new MatchAllDocsQuery(),
+                asList(term(KEYWORD_FIELD), term(GEO_POINT_FIELD)),
+                NONE_DECORATOR,
+                iw -> {},
+                f -> fail("should throw exception")
+            )
+        );
+    }
+
+    public void testMinDocCount() throws IOException {
+        testAggregation(new MatchAllDocsQuery(), fieldConfigs(asList(KEYWORD_FIELD, INT_FIELD)), b -> b.minDocCount(2), iw -> {
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(INT_FIELD, 1)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(INT_FIELD, 1)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(INT_FIELD, 2)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(INT_FIELD, 1)));
+            iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(INT_FIELD, 2)));
+        }, h -> {
+            MatcherAssert.assertThat(h.getBuckets(), hasSize(1));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L)));
+            MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+        });
+    }
+
+    public void testIncludeExclude() throws IOException {
+        testAggregation(
+            new MatchAllDocsQuery(),
+            asList(
+                new MultiTermsValuesSourceConfig.Builder().setFieldName(KEYWORD_FIELD)
+                    .setIncludeExclude(new IncludeExclude("a", null))
+                    .build(),
+                term(INT_FIELD)
+            ),
+            NONE_DECORATOR,
+            iw -> {
+                iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(INT_FIELD, 1)));
+                iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("a")), new NumericDocValuesField(INT_FIELD, 1)));
+                iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("b")), new NumericDocValuesField(INT_FIELD, 1)));
+                iw.addDocument(asList(new SortedDocValuesField(KEYWORD_FIELD, new BytesRef("c")), new NumericDocValuesField(INT_FIELD, 2)));
+            },
+            h -> {
+                MatcherAssert.assertThat(h.getBuckets(), hasSize(1));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getKey(), contains(equalTo("a"), equalTo(1L)));
+                MatcherAssert.assertThat(h.getBuckets().get(0).getDocCount(), equalTo(2L));
+            }
+        );
+    }
+
+    public void testEmptyAggregations() throws IOException {
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        BigArrays bigArrays = new BigArrays(new MockPageCacheRecycler(Settings.EMPTY), new NoneCircuitBreakerService(), "");
+        IndexService indexService = mock(IndexService.class);
+        when(indexService.getShardOrNull(0)).thenReturn(indexShard);
+        IndexCache cache = mock(IndexCache.class);
+        when(cache.bitsetFilterCache()).thenReturn(null);
+        when(indexService.cache()).thenReturn(cache);
+        SearchContext context = new TestSearchContext(bigArrays, indexService);
+        when(indexService.newQueryShardContext(0, null, () -> 0L, null)).thenReturn(queryShardContext);
+        AggregatorFactories factories = AggregatorFactories.EMPTY;
+        boolean showTermDocCountError = true;
+        MultiTermsAggregator.InternalValuesSource internalValuesSources = mock(MultiTermsAggregator.InternalValuesSource.class);
+        DocValueFormat format = mock(DocValueFormat.class);
+        BucketOrder order = mock(BucketOrder.class);
+        Aggregator.SubAggCollectionMode collectMode = Aggregator.SubAggCollectionMode.BREADTH_FIRST;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = mock(TermsAggregator.BucketCountThresholds.class);
+        Aggregator parent = mock(Aggregator.class);
+        CardinalityUpperBound cardinality = CardinalityUpperBound.ONE;
+        Map<String, Object> metadata = new HashMap<>();
+        String k1 = UUID.randomUUID().toString();
+        String v1 = UUID.randomUUID().toString();
+        metadata.put(k1, v1);
+
+        MultiTermsAggregator mAgg = new MultiTermsAggregator(
+            AGG_NAME,
+            factories,
+            showTermDocCountError,
+            List.of(internalValuesSources),
+            List.of(format),
+            order,
+            collectMode,
+            bucketCountThresholds,
+            context,
+            parent,
+            cardinality,
+            metadata
+        );
+        InternalAggregation emptyAgg = mAgg.buildEmptyAggregation();
+
+        MatcherAssert.assertThat(emptyAgg.getName(), equalTo(AGG_NAME));
+        MatcherAssert.assertThat(emptyAgg, instanceOf(InternalMultiTerms.class));
+
+        InternalMultiTerms mt = (InternalMultiTerms) emptyAgg;
+        MatcherAssert.assertThat(mt.getMetadata().keySet(), contains(k1));
+        MatcherAssert.assertThat(mt.getMetadata().get(k1), equalTo(v1));
+        MatcherAssert.assertThat(mt.getBuckets(), empty());
+    }
+
+    private void testAggregation(
+        Query query,
+        List<MultiTermsValuesSourceConfig> terms,
+        Consumer<MultiTermsAggregationBuilder> decorator,
+        CheckedConsumer<RandomIndexWriter, IOException> indexBuilder,
+        Consumer<InternalMultiTerms> verify
+    ) throws IOException {
+        MultiTermsAggregationBuilder builder = createTestAggregatorBuilder(terms);
+        if (decorator != NONE_DECORATOR) {
+            decorator.accept(builder);
+        }
+        testCase(builder, query, indexBuilder, verify, mappedFieldTypeMap.values().toArray(new MappedFieldType[] {}));
+    }
+
+    private MultiTermsValuesSourceConfig term(String field) {
+        return new MultiTermsValuesSourceConfig.Builder().setFieldName(field).build();
+    }
+
+    private MultiTermsAggregationBuilder createTestAggregatorBuilder(List<MultiTermsValuesSourceConfig> termsConfig) {
+        MultiTermsAggregationBuilder factory = new MultiTermsAggregationBuilder(AGG_NAME);
+        factory.terms(termsConfig);
+
+        if (randomBoolean()) {
+            factory.size(randomIntBetween(10, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.shardSize(randomIntBetween(10, Integer.MAX_VALUE));
+        }
+        if (randomBoolean()) {
+            factory.showTermDocCountError(randomBoolean());
+        }
+        return factory;
+    }
+
+    private List<MultiTermsValuesSourceConfig> fieldConfigs(List<String> terms) {
+        List<MultiTermsValuesSourceConfig> termConfigs = new ArrayList<>();
+        for (String term : terms) {
+            termConfigs.add(term(term));
+        }
+        return termConfigs;
+    }
+
+    private static DateFieldMapper.DateFieldType dateFieldType(String name) {
+        return new DateFieldMapper.DateFieldType(
+            name,
+            true,
+            false,
+            true,
+            DateFormatter.forPattern("date"),
+            DateFieldMapper.Resolution.MILLISECONDS,
+            null,
+            Collections.emptyMap()
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregatorTests.java
index 13e41d5a2e543..4988e7141bb9c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/NumericTermsAggregatorTests.java
@@ -36,13 +36,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.automaton.RegExp;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.search.aggregations.AggregationExecutionException;
@@ -116,7 +115,7 @@ public void testMatchAllDocs() throws IOException {
     }
 
     public void testBadIncludeExclude() throws IOException {
-        IncludeExclude includeExclude = new IncludeExclude(new RegExp("foo"), null);
+        IncludeExclude includeExclude = new IncludeExclude("foo", null);
 
         // Numerics don't support any regex include/exclude, so should fail no matter what we do
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorTests.java
index 9a9a03e715644..28cec4df5f7d7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/RareTermsAggregatorTests.java
@@ -41,7 +41,6 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -49,22 +48,23 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.RangeFieldMapper;
 import org.opensearch.index.mapper.RangeType;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.aggregations.Aggregation;
@@ -376,25 +376,13 @@ public void testInsideTerms() throws IOException {
 
             StringTerms.Bucket even = terms.getBucketByKey("even");
             InternalRareTerms<?, ?> evenRare = even.getAggregations().get("rare");
-            assertEquals(
-                evenRare.getBuckets().stream().map(InternalRareTerms.Bucket::getKeyAsString).collect(toList()),
-                org.opensearch.common.collect.List.of("2")
-            );
-            assertEquals(
-                evenRare.getBuckets().stream().map(InternalRareTerms.Bucket::getDocCount).collect(toList()),
-                org.opensearch.common.collect.List.of(2L)
-            );
+            assertEquals(evenRare.getBuckets().stream().map(InternalRareTerms.Bucket::getKeyAsString).collect(toList()), List.of("2"));
+            assertEquals(evenRare.getBuckets().stream().map(InternalRareTerms.Bucket::getDocCount).collect(toList()), List.of(2L));
 
             StringTerms.Bucket odd = terms.getBucketByKey("odd");
             InternalRareTerms<?, ?> oddRare = odd.getAggregations().get("rare");
-            assertEquals(
-                oddRare.getBuckets().stream().map(InternalRareTerms.Bucket::getKeyAsString).collect(toList()),
-                org.opensearch.common.collect.List.of("1")
-            );
-            assertEquals(
-                oddRare.getBuckets().stream().map(InternalRareTerms.Bucket::getDocCount).collect(toList()),
-                org.opensearch.common.collect.List.of(1L)
-            );
+            assertEquals(oddRare.getBuckets().stream().map(InternalRareTerms.Bucket::getKeyAsString).collect(toList()), List.of("1"));
+            assertEquals(oddRare.getBuckets().stream().map(InternalRareTerms.Bucket::getDocCount).collect(toList()), List.of(1L));
         }
     }
 
@@ -551,7 +539,7 @@ private List<Document> generateDocsWithNested(String id, int value, int[] nested
         for (int nestedValue : nestedValues) {
             Document document = new Document();
             document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(id), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-            document.add(new Field(TypeFieldMapper.NAME, "__nested_object", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+            document.add(new Field(NestedPathFieldMapper.NAME, "nested_object", NestedPathFieldMapper.Defaults.FIELD_TYPE));
             document.add(new SortedNumericDocValuesField("nested_value", nestedValue));
             documents.add(document);
         }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificanceHeuristicTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificanceHeuristicTests.java
index 9c7196db68e97..77424e17dfc94 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificanceHeuristicTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificanceHeuristicTests.java
@@ -34,19 +34,18 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -58,8 +57,8 @@
 import org.opensearch.search.aggregations.bucket.terms.heuristic.PercentageScore;
 import org.opensearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
 import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -131,7 +130,16 @@ public void testStreamResponse() throws Exception {
                 DocValueFormat.RAW,
                 randomDoubleBetween(0, 100, true)
             );
-            return new SignificantLongTerms("some_name", 1, 1, null, DocValueFormat.RAW, 10, 20, heuristic, singletonList(bucket));
+            return new SignificantLongTerms(
+                "some_name",
+                null,
+                DocValueFormat.RAW,
+                10,
+                20,
+                heuristic,
+                singletonList(bucket),
+                new TermsAggregator.BucketCountThresholds(1, 0, 1, 0)
+            );
         } else {
             SignificantStringTerms.Bucket bucket = new SignificantStringTerms.Bucket(
                 new BytesRef("someterm"),
@@ -143,7 +151,16 @@ public void testStreamResponse() throws Exception {
                 DocValueFormat.RAW,
                 randomDoubleBetween(0, 100, true)
             );
-            return new SignificantStringTerms("some_name", 1, 1, null, DocValueFormat.RAW, 10, 20, heuristic, singletonList(bucket));
+            return new SignificantStringTerms(
+                "some_name",
+                null,
+                DocValueFormat.RAW,
+                10,
+                20,
+                heuristic,
+                singletonList(bucket),
+                new TermsAggregator.BucketCountThresholds(1, 0, 1, 0)
+            );
         }
     }
 
@@ -210,14 +227,13 @@ SignificantStringTerms createAggregation(
         ) {
             return new SignificantStringTerms(
                 "sig_terms",
-                2,
-                -1,
                 emptyMap(),
                 DocValueFormat.RAW,
                 subsetSize,
                 supersetSize,
                 significanceHeuristic,
-                buckets
+                buckets,
+                new TermsAggregator.BucketCountThresholds(-1, 0, 2, 0)
             );
         }
 
@@ -246,14 +262,13 @@ SignificantLongTerms createAggregation(
         ) {
             return new SignificantLongTerms(
                 "sig_terms",
-                2,
-                -1,
                 emptyMap(),
                 DocValueFormat.RAW,
                 subsetSize,
                 supersetSize,
                 significanceHeuristic,
-                buckets
+                buckets,
+                new TermsAggregator.BucketCountThresholds(-1, 0, 2, 0)
             );
         }
 
@@ -337,7 +352,7 @@ protected SignificanceHeuristic parseFromBuilder(SignificanceHeuristic significa
         stBuilder.significanceHeuristic(significanceHeuristic).field("text").minDocCount(200);
         XContentBuilder stXContentBuilder = XContentFactory.jsonBuilder();
         stBuilder.internalXContent(stXContentBuilder, null);
-        XContentParser stParser = createParser(JsonXContent.jsonXContent, Strings.toString(stXContentBuilder));
+        XContentParser stParser = createParser(JsonXContent.jsonXContent, stXContentBuilder.toString());
         return parseSignificanceHeuristic(stParser);
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTermsTests.java
index 886e4d8267578..38b478efd004b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantLongTermsTests.java
@@ -85,7 +85,17 @@ protected InternalSignificantTerms createTestInstance(
             bucket.updateScore(significanceHeuristic);
             buckets.add(bucket);
         }
-        return new SignificantLongTerms(name, requiredSize, 1L, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets);
+
+        return new SignificantLongTerms(
+            name,
+            metadata,
+            format,
+            subsetSize,
+            supersetSize,
+            significanceHeuristic,
+            buckets,
+            new TermsAggregator.BucketCountThresholds(1L, 0, requiredSize, 0)
+        );
     }
 
     @Override
@@ -150,14 +160,13 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
             }
             return new SignificantLongTerms(
                 name,
-                requiredSize,
-                minDocCount,
                 metadata,
                 format,
                 subsetSize,
                 supersetSize,
                 significanceHeuristic,
-                buckets
+                buckets,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0)
             );
         } else {
             String name = instance.getName();
@@ -185,7 +194,7 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 default:
                     throw new AssertionError("Illegal randomisation branch");
             }
-            return new UnmappedSignificantTerms(name, requiredSize, minDocCount, metadata);
+            return new UnmappedSignificantTerms(name, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTermsTests.java
index 63a08a7aa1683..3ac30248ef353 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantStringTermsTests.java
@@ -80,14 +80,13 @@ protected InternalSignificantTerms createTestInstance(
         }
         return new SignificantStringTerms(
             name,
-            requiredSize,
-            1L,
             metadata,
             format,
             subsetSize,
             supersetSize,
             significanceHeuristic,
-            buckets
+            buckets,
+            new TermsAggregator.BucketCountThresholds(1L, 0, requiredSize, 0)
         );
     }
 
@@ -153,14 +152,13 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
             }
             return new SignificantStringTerms(
                 name,
-                requiredSize,
-                minDocCount,
                 metadata,
                 format,
                 subsetSize,
                 supersetSize,
                 significanceHeuristic,
-                buckets
+                buckets,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0)
             );
         } else {
             String name = instance.getName();
@@ -188,7 +186,7 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 default:
                     throw new AssertionError("Illegal randomisation branch");
             }
-            return new UnmappedSignificantTerms(name, requiredSize, minDocCount, metadata);
+            return new UnmappedSignificantTerms(name, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
         }
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorTests.java
index 883196d290154..a106ef47dc469 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTermsAggregatorTests.java
@@ -43,12 +43,12 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorTests.java
index ce5c361ffcf69..e9b2d40fd4ede 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/SignificantTextAggregatorTests.java
@@ -50,6 +50,7 @@
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.mapper.BinaryFieldMapper;
+import org.opensearch.index.mapper.FlatObjectFieldMapper;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.TextFieldMapper;
@@ -102,7 +103,8 @@ protected List<ValuesSourceType> getSupportedValuesSourceTypes() {
     protected List<String> unsupportedMappedFieldTypes() {
         return Arrays.asList(
             BinaryFieldMapper.CONTENT_TYPE, // binary fields are not supported because they do not have analyzers
-            GeoPointFieldMapper.CONTENT_TYPE // geopoint fields cannot use term queries
+            GeoPointFieldMapper.CONTENT_TYPE, // geopoint fields cannot use term queries
+            FlatObjectFieldMapper.CONTENT_TYPE // flat_object fields are not supported aggregations
         );
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/StringTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/StringTermsTests.java
index 6757c8e00f83d..deba96fd3ae19 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/StringTermsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/StringTermsTests.java
@@ -140,15 +140,14 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 name,
                 stringTerms.reduceOrder,
                 order,
-                requiredSize,
-                minDocCount,
                 metadata,
                 format,
                 shardSize,
                 showTermDocCountError,
                 otherDocCount,
                 buckets,
-                docCountError
+                docCountError,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, shardSize)
             );
         } else {
             String name = instance.getName();
@@ -177,7 +176,7 @@ protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
                 default:
                     throw new AssertionError("Illegal randomisation branch");
             }
-            return new UnmappedTerms(name, order, requiredSize, minDocCount, metadata);
+            return new UnmappedTerms(name, order, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
         }
     }
 
@@ -206,6 +205,12 @@ private BytesRef[] generateRandomDict() {
         long minDocCount = 1;
         int requiredSize = 3;
         int shardSize = requiredSize + 2;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+            minDocCount,
+            0,
+            requiredSize,
+            shardSize
+        );
         DocValueFormat format = DocValueFormat.RAW;
         long otherDocCount = 0;
         List<StringTerms.Bucket> buckets = new ArrayList<>();
@@ -226,15 +231,14 @@ private BytesRef[] generateRandomDict() {
             name,
             reduceOrder,
             order,
-            requiredSize,
-            minDocCount,
             metadata,
             format,
             shardSize,
             showTermDocCountError,
             otherDocCount,
             buckets,
-            docCountError
+            docCountError,
+            bucketCountThresholds
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
index a9e819e7cbaf2..80744ecde4d69 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/TermsAggregatorTests.java
@@ -44,21 +44,22 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
@@ -66,15 +67,14 @@
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.mapper.RangeFieldMapper;
 import org.opensearch.index.mapper.RangeType;
 import org.opensearch.index.mapper.SeqNoFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.mapper.Uid;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptEngine;
@@ -1464,7 +1464,7 @@ private List<Document> generateDocsWithNested(String id, int value, int[] nested
         for (int nestedValue : nestedValues) {
             Document document = new Document();
             document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(id), IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
-            document.add(new Field(TypeFieldMapper.NAME, "__nested_object", TypeFieldMapper.Defaults.NESTED_FIELD_TYPE));
+            document.add(new Field(NestedPathFieldMapper.NAME, "nested_object", NestedPathFieldMapper.Defaults.FIELD_TYPE));
             document.add(new SortedNumericDocValuesField("nested_value", nestedValue));
             documents.add(document);
         }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTermsTests.java b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTermsTests.java
new file mode 100644
index 0000000000000..478961c2a404c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/bucket/terms/UnsignedLongTermsTests.java
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.bucket.terms;
+
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.aggregations.BucketOrder;
+import org.opensearch.search.aggregations.InternalAggregations;
+import org.opensearch.search.aggregations.ParsedMultiBucketAggregation;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class UnsignedLongTermsTests extends InternalTermsTestCase {
+
+    @Override
+    protected InternalTerms<?, ?> createTestInstance(
+        String name,
+        Map<String, Object> metadata,
+        InternalAggregations aggregations,
+        boolean showTermDocCountError,
+        long docCountError
+    ) {
+        BucketOrder order = BucketOrder.count(false);
+        long minDocCount = 1;
+        int requiredSize = 3;
+        int shardSize = requiredSize + 2;
+        TermsAggregator.BucketCountThresholds bucketCountThresholds = new TermsAggregator.BucketCountThresholds(
+            minDocCount,
+            0,
+            requiredSize,
+            shardSize
+        );
+        DocValueFormat format = randomNumericDocValueFormat();
+        long otherDocCount = 0;
+        List<UnsignedLongTerms.Bucket> buckets = new ArrayList<>();
+        final int numBuckets = randomNumberOfBuckets();
+        Set<BigInteger> terms = new HashSet<>();
+        for (int i = 0; i < numBuckets; ++i) {
+            BigInteger term = randomValueOtherThanMany(l -> terms.add(l) == false, InternalTermsTestCase::randomUnsignedLong);
+            int docCount = randomIntBetween(1, 100);
+            buckets.add(new UnsignedLongTerms.Bucket(term, docCount, aggregations, showTermDocCountError, docCountError, format));
+        }
+        BucketOrder reduceOrder = rarely() ? order : BucketOrder.key(true);
+        Collections.sort(buckets, reduceOrder.comparator());
+        return new UnsignedLongTerms(
+            name,
+            reduceOrder,
+            order,
+            metadata,
+            format,
+            shardSize,
+            showTermDocCountError,
+            otherDocCount,
+            buckets,
+            docCountError,
+            bucketCountThresholds
+        );
+    }
+
+    @Override
+    protected Class<? extends ParsedMultiBucketAggregation> implementationClass() {
+        return ParsedUnsignedLongTerms.class;
+    }
+
+    @Override
+    protected InternalTerms<?, ?> mutateInstance(InternalTerms<?, ?> instance) {
+        if (instance instanceof UnsignedLongTerms) {
+            UnsignedLongTerms longTerms = (UnsignedLongTerms) instance;
+            String name = longTerms.getName();
+            BucketOrder order = longTerms.order;
+            int requiredSize = longTerms.requiredSize;
+            long minDocCount = longTerms.minDocCount;
+            DocValueFormat format = longTerms.format;
+            int shardSize = longTerms.getShardSize();
+            boolean showTermDocCountError = longTerms.showTermDocCountError;
+            long otherDocCount = longTerms.getSumOfOtherDocCounts();
+            List<UnsignedLongTerms.Bucket> buckets = longTerms.getBuckets();
+            long docCountError = longTerms.getDocCountError();
+            Map<String, Object> metadata = longTerms.getMetadata();
+            switch (between(0, 8)) {
+                case 0:
+                    name += randomAlphaOfLength(5);
+                    break;
+                case 1:
+                    requiredSize += between(1, 100);
+                    break;
+                case 2:
+                    minDocCount += between(1, 100);
+                    break;
+                case 3:
+                    shardSize += between(1, 100);
+                    break;
+                case 4:
+                    showTermDocCountError = showTermDocCountError == false;
+                    break;
+                case 5:
+                    otherDocCount += between(1, 100);
+                    break;
+                case 6:
+                    docCountError += between(1, 100);
+                    break;
+                case 7:
+                    buckets = new ArrayList<>(buckets);
+                    buckets.add(
+                        new UnsignedLongTerms.Bucket(
+                            randomUnsignedLong(),
+                            randomNonNegativeLong(),
+                            InternalAggregations.EMPTY,
+                            showTermDocCountError,
+                            docCountError,
+                            format
+                        )
+                    );
+                    break;
+                case 8:
+                    if (metadata == null) {
+                        metadata = new HashMap<>(1);
+                    } else {
+                        metadata = new HashMap<>(instance.getMetadata());
+                    }
+                    metadata.put(randomAlphaOfLength(15), randomInt());
+                    break;
+                default:
+                    throw new AssertionError("Illegal randomisation branch");
+            }
+            Collections.sort(buckets, longTerms.reduceOrder.comparator());
+            return new UnsignedLongTerms(
+                name,
+                longTerms.reduceOrder,
+                order,
+                metadata,
+                format,
+                shardSize,
+                showTermDocCountError,
+                otherDocCount,
+                buckets,
+                docCountError,
+                new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, shardSize)
+            );
+        } else {
+            String name = instance.getName();
+            BucketOrder order = instance.order;
+            int requiredSize = instance.requiredSize;
+            long minDocCount = instance.minDocCount;
+            Map<String, Object> metadata = instance.getMetadata();
+            switch (between(0, 3)) {
+                case 0:
+                    name += randomAlphaOfLength(5);
+                    break;
+                case 1:
+                    requiredSize += between(1, 100);
+                    break;
+                case 2:
+                    minDocCount += between(1, 100);
+                    break;
+                case 3:
+                    if (metadata == null) {
+                        metadata = new HashMap<>(1);
+                    } else {
+                        metadata = new HashMap<>(instance.getMetadata());
+                    }
+                    metadata.put(randomAlphaOfLength(15), randomInt());
+                    break;
+                default:
+                    throw new AssertionError("Illegal randomisation branch");
+            }
+            return new UnmappedTerms(name, order, new TermsAggregator.BucketCountThresholds(minDocCount, 0, requiredSize, 0), metadata);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractGeoTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractGeoTestCase.java
index 5dd8421bf5fc1..e02c00005df9b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractGeoTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractGeoTestCase.java
@@ -32,37 +32,40 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.ObjectIntMap;
-import com.carrotsearch.hppc.ObjectObjectHashMap;
-import com.carrotsearch.hppc.ObjectObjectMap;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.Strings;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.utils.Geohash;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.sort.SortBuilders;
 import org.opensearch.search.sort.SortOrder;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 import org.opensearch.test.geo.RandomGeoGenerator;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.equalTo;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public abstract class AbstractGeoTestCase extends OpenSearchIntegTestCase {
+public abstract class AbstractGeoTestCase extends ParameterizedOpenSearchIntegTestCase {
 
     protected static final String SINGLE_VALUED_FIELD_NAME = "geo_value";
     protected static final String MULTI_VALUED_FIELD_NAME = "geo_values";
@@ -73,16 +76,32 @@ public abstract class AbstractGeoTestCase extends OpenSearchIntegTestCase {
     protected static final String DATELINE_IDX_NAME = "dateline_idx";
     protected static final String HIGH_CARD_IDX_NAME = "high_card_idx";
     protected static final String IDX_ZERO_NAME = "idx_zero";
-
     protected static int numDocs;
     protected static int numUniqueGeoPoints;
     protected static GeoPoint[] singleValues, multiValues;
     protected static GeoPoint singleTopLeft, singleBottomRight, multiTopLeft, multiBottomRight, singleCentroid, multiCentroid,
         unmappedCentroid;
-    protected static ObjectIntMap<String> expectedDocCountsForGeoHash = null;
-    protected static ObjectObjectMap<String, GeoPoint> expectedCentroidsForGeoHash = null;
+    protected static Map<String, Integer> expectedDocCountsForGeoHash = null;
+    protected static Map<String, GeoPoint> expectedCentroidsForGeoHash = null;
     protected static final double GEOHASH_TOLERANCE = 1E-5D;
 
+    public AbstractGeoTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex(UNMAPPED_IDX_NAME);
@@ -109,8 +128,8 @@ public void setupSuiteScopeCluster() throws Exception {
 
         numDocs = randomIntBetween(6, 20);
         numUniqueGeoPoints = randomIntBetween(1, numDocs);
-        expectedDocCountsForGeoHash = new ObjectIntHashMap<>(numDocs * 2);
-        expectedCentroidsForGeoHash = new ObjectObjectHashMap<>(numDocs * 2);
+        expectedDocCountsForGeoHash = new HashMap<>(numDocs * 2);
+        expectedCentroidsForGeoHash = new HashMap<>(numDocs * 2);
 
         singleValues = new GeoPoint[numUniqueGeoPoints];
         for (int i = 0; i < singleValues.length; i++) {
@@ -262,7 +281,7 @@ public void setupSuiteScopeCluster() throws Exception {
         long totalHits = response.getHits().getTotalHits().value;
         XContentBuilder builder = XContentFactory.jsonBuilder();
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        logger.info("Full high_card_idx Response Content:\n{ {} }", Strings.toString(builder));
+        logger.info("Full high_card_idx Response Content:\n{ {} }", builder.toString());
         for (int i = 0; i < totalHits; i++) {
             SearchHit searchHit = response.getHits().getAt(i);
             assertThat("Hit " + i + " with id: " + searchHit.getId(), searchHit.getIndex(), equalTo("high_card_idx"));
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesTestCase.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
index 16ab382bae6eb..0144f9413e4b0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/AbstractPercentilesTestCase.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregation.CommonFields;
 import org.opensearch.search.aggregations.InternalAggregation;
@@ -162,6 +161,6 @@ public void testEmptyRanksXContent() throws IOException {
                 + "}";
         }
 
-        assertThat(Strings.toString(builder), equalTo(expected));
+        assertThat(builder.toString(), equalTo(expected));
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/AvgAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/AvgAggregatorTests.java
index 99c6ed121011e..f8eab720f8d6c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/AvgAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/AvgAggregatorTests.java
@@ -39,12 +39,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorTests.java
index e33851f286613..cdd17e2fa7dd6 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/CardinalityAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.IntPoint;
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.SortedNumericDocValuesField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorTests.java
index 6fab4436182c2..69c5ac88b62f1 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/ExtendedStatsAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsTests.java
deleted file mode 100644
index e132426680fc8..0000000000000
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoBoundsTests.java
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.search.aggregations.metrics;
-
-import org.opensearch.search.aggregations.BaseAggregationTestCase;
-
-public class GeoBoundsTests extends BaseAggregationTestCase<GeoBoundsAggregationBuilder> {
-
-    @Override
-    protected GeoBoundsAggregationBuilder createTestAggregatorBuilder() {
-        GeoBoundsAggregationBuilder factory = new GeoBoundsAggregationBuilder(randomAlphaOfLengthBetween(1, 20));
-        String field = randomAlphaOfLengthBetween(3, 20);
-        factory.field(field);
-        if (randomBoolean()) {
-            factory.wrapLongitude(randomBoolean());
-        }
-        if (randomBoolean()) {
-            factory.missing("0,0");
-        }
-        return factory;
-    }
-
-}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorTests.java
index 6883a7ff15953..af936d253dd7e 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/GeoCentroidAggregatorTests.java
@@ -34,10 +34,10 @@
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.LatLonDocValuesField;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregatorTests.java
index e459b63aa058b..1aaaa1e1bd262 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentileRanksAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregatorTests.java
index bbf7f6cfd9cc2..4c0534c95a116 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/HDRPercentilesAggregatorTests.java
@@ -39,12 +39,12 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.KeywordFieldMapper;
@@ -113,16 +113,9 @@ public void testRangeField() throws IOException {
         MappedFieldType fieldType = new RangeFieldMapper.RangeFieldType(fieldName, RangeType.DOUBLE);
         RangeFieldMapper.Range range = new RangeFieldMapper.Range(RangeType.DOUBLE, 1.0D, 5.0D, true, true);
         BytesRef encodedRange = RangeType.DOUBLE.encodeRanges(Collections.singleton(range));
-        expectThrows(
-            IllegalArgumentException.class,
-            () -> testCase(
-                new DocValuesFieldExistsQuery(fieldName),
-                iw -> { iw.addDocument(singleton(new BinaryDocValuesField(fieldName, encodedRange))); },
-                hdr -> {},
-                fieldType,
-                fieldName
-            )
-        );
+        expectThrows(IllegalArgumentException.class, () -> testCase(new DocValuesFieldExistsQuery(fieldName), iw -> {
+            iw.addDocument(singleton(new BinaryDocValuesField(fieldName, encodedRange)));
+        }, hdr -> {}, fieldType, fieldName));
     }
 
     public void testNoMatchingField() throws IOException {
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparseTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparseTests.java
index ce47862c9884b..408a2069d2306 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparseTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusSparseTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.BitMixer;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.common.util.BitMixer;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.Matchers;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusTests.java
index 0726621855b47..53349e4a840d1 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/HyperLogLogPlusPlusTests.java
@@ -32,15 +32,16 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.BitMixer;
-import com.carrotsearch.hppc.IntHashSet;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.common.util.BitMixer;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.HashSet;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 
 import static org.opensearch.search.aggregations.metrics.AbstractHyperLogLog.MAX_PRECISION;
@@ -80,7 +81,7 @@ public void testAccuracy() {
         final int numValues = randomIntBetween(1, 100000);
         final int maxValue = randomIntBetween(1, randomBoolean() ? 1000 : 100000);
         final int p = randomIntBetween(14, MAX_PRECISION);
-        IntHashSet set = new IntHashSet();
+        final Set<Integer> set = new HashSet<>();
         HyperLogLogPlusPlus e = new HyperLogLogPlusPlus(p, BigArrays.NON_RECYCLING_INSTANCE, 1);
         for (int i = 0; i < numValues; ++i) {
             final int n = randomInt(maxValue);
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalCardinalityTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalCardinalityTests.java
index e574b19d201fa..0b45328641df3 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalCardinalityTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalCardinalityTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.BitMixer;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.aggregations.ParsedAggregation;
 import org.opensearch.test.InternalAggregationTestCase;
 import org.junit.After;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
index 3540227d839a6..3d1b385147e50 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesRanksTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
 import org.opensearch.search.DocValueFormat;
 
 import java.util.Arrays;
@@ -40,6 +39,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
 public class InternalHDRPercentilesRanksTests extends InternalPercentilesRanksTestCase<InternalHDRPercentileRanks> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
index 6d947c6b68e36..f96a88c86ea1c 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalHDRPercentilesTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.HdrHistogram.DoubleHistogram;
 import org.opensearch.search.DocValueFormat;
 
 import java.util.Arrays;
@@ -41,6 +40,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.HdrHistogram.DoubleHistogram;
+
 import static java.util.Collections.emptyMap;
 
 public class InternalHDRPercentilesTests extends InternalPercentilesTestCase<InternalHDRPercentiles> {
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetricTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetricTests.java
index 69c53d1a526e8..1a10a2fa35f84 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetricTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalScriptedMetricTests.java
@@ -279,12 +279,7 @@ protected InternalScriptedMetric mutateInstance(InternalScriptedMetric instance)
 
     public void testOldSerialization() throws IOException {
         // A single element list looks like a fully reduced agg
-        InternalScriptedMetric original = new InternalScriptedMetric(
-            "test",
-            org.opensearch.common.collect.List.of("foo"),
-            new Script("test"),
-            null
-        );
+        InternalScriptedMetric original = new InternalScriptedMetric("test", List.of("foo"), new Script("test"), null);
         original.mergePipelineTreeForBWCSerialization(PipelineTree.EMPTY);
         InternalScriptedMetric roundTripped = (InternalScriptedMetric) copyNamedWriteable(
             original,
@@ -295,12 +290,7 @@ public void testOldSerialization() throws IOException {
         assertThat(roundTripped, equalTo(original));
 
         // A multi-element list looks like a non-reduced agg
-        InternalScriptedMetric unreduced = new InternalScriptedMetric(
-            "test",
-            org.opensearch.common.collect.List.of("foo", "bar"),
-            new Script("test"),
-            null
-        );
+        InternalScriptedMetric unreduced = new InternalScriptedMetric("test", List.of("foo", "bar"), new Script("test"), null);
         unreduced.mergePipelineTreeForBWCSerialization(PipelineTree.EMPTY);
         Exception e = expectThrows(
             IllegalArgumentException.class,
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalStatsTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalStatsTests.java
index db45e28522c62..7aa6daa9768b0 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalStatsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalStatsTests.java
@@ -31,10 +31,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.ParsedAggregation;
@@ -263,7 +262,7 @@ public void testDoXContentBody() throws IOException {
                 + "\"";
         }
         expected += "\n}";
-        assertEquals(expected, Strings.toString(builder));
+        assertEquals(expected, builder.toString());
 
         // count is zero
         format = randomNumericDocValueFormat();
@@ -285,7 +284,7 @@ public void testDoXContentBody() throws IOException {
                 + "  \"avg\" : null,\n"
                 + "  \"sum\" : 0.0\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalTopHitsTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalTopHitsTests.java
index ec4a0e1e4a675..9358fa568db6a 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalTopHitsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/InternalTopHitsTests.java
@@ -41,20 +41,20 @@
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.ParsedAggregation;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
 import org.opensearch.test.NotEqualMessageBuilder;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/MaxAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/MaxAggregatorTests.java
index 3d5ad3f5c163c..3b965a51275b6 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/MaxAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/MaxAggregatorTests.java
@@ -49,13 +49,13 @@
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.NoMergePolicy;
 import org.apache.lucene.index.PointValues;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.Bits;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.collect.Tuple;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorTests.java
index 0cf898090e752..794dd44b2db94 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.IndexableField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -282,7 +282,7 @@ public static IsCloseToRelative closeToRelative(double expected, double error) {
         }
 
         public static IsCloseToRelative closeToRelative(double expected) {
-            return closeToRelative(expected, 0.1);
+            return closeToRelative(expected, 0.25); // 0.25 = q(1-q) where q = quartile; for median, q = 0.5.
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/MetricAggScriptPlugin.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/MetricAggScriptPlugin.java
index cdc7ef260c750..e29eb95a52cd7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/MetricAggScriptPlugin.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/MetricAggScriptPlugin.java
@@ -32,6 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import org.opensearch.script.MockScriptPlugin;
+import org.opensearch.search.lookup.LeafDocLookup;
+import org.opensearch.test.OpenSearchTestCase;
+
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -39,10 +43,6 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-import org.opensearch.script.MockScriptPlugin;
-import org.opensearch.search.lookup.LeafDocLookup;
-import org.opensearch.test.OpenSearchTestCase;
-
 /**
  * Provides a number of dummy scripts for tests.
  *
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/MinAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/MinAggregatorTests.java
index 05b3c5c7e57db..69cd63e4b9e84 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/MinAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/MinAggregatorTests.java
@@ -50,18 +50,19 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.IpFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
@@ -69,7 +70,6 @@
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.NumberFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptEngine;
@@ -302,13 +302,9 @@ public void testUnsupportedType() {
 
         IllegalArgumentException e = expectThrows(
             IllegalArgumentException.class,
-            () -> testCase(
-                aggregationBuilder,
-                new MatchAllDocsQuery(),
-                iw -> { iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo")))); },
-                (Consumer<InternalMin>) min -> { fail("Should have thrown exception"); },
-                fieldType
-            )
+            () -> testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+                iw.addDocument(singleton(new SortedSetDocValuesField("string", new BytesRef("foo"))));
+            }, (Consumer<InternalMin>) min -> { fail("Should have thrown exception"); }, fieldType)
         );
         assertEquals("Field [not_a_number] of type [keyword] is not supported for aggregation [min]", e.getMessage());
     }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesMethodTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesMethodTests.java
index 7d4a02c7a2c1f..6634840b9af45 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesMethodTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesMethodTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.search.aggregations.metrics;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesTests.java
index b8532b568d9c8..4e3454f41d810 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/PercentilesTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorTests.java
index f2a61521eff1f..53e5f2bfb53bb 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/ScriptedMetricAggregatorTests.java
@@ -37,23 +37,23 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.script.MockScriptEngine;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptEngine;
@@ -593,12 +593,9 @@ public void testInitScriptMakesArray() throws IOException {
             .mapScript(MAP_SCRIPT)
             .combineScript(COMBINE_SCRIPT)
             .reduceScript(REDUCE_SCRIPT);
-        testCase(
-            aggregationBuilder,
-            new MatchAllDocsQuery(),
-            iw -> { iw.addDocument(new Document()); },
-            (InternalScriptedMetric r) -> { assertEquals(1, r.aggregation()); }
-        );
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> { iw.addDocument(new Document()); }, (InternalScriptedMetric r) -> {
+            assertEquals(1, r.aggregation());
+        });
     }
 
     public void testAsSubAgg() throws IOException {
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/StatsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/StatsAggregatorTests.java
index d8d736595164a..85a1ed20df4c9 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/StatsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/StatsAggregatorTests.java
@@ -37,10 +37,10 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.settings.Settings;
@@ -470,7 +470,7 @@ protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldTy
 
     @Override
     protected ScriptService getMockScriptService() {
-        final Map<String, Function<Map<String, Object>, Object>> scripts = org.opensearch.common.collect.Map.of(
+        final Map<String, Function<Map<String, Object>, Object>> scripts = Map.of(
             VALUE_SCRIPT_NAME,
             vars -> ((Number) vars.get("_value")).doubleValue() + 1,
             FIELD_SCRIPT_NAME,
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/SumAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/SumAggregatorTests.java
index 8c0087ca0b87d..b029417999c6e 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/SumAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/SumAggregatorTests.java
@@ -40,7 +40,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
@@ -48,6 +47,7 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
@@ -418,7 +418,7 @@ protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldTy
 
     @Override
     protected ScriptService getMockScriptService() {
-        final Map<String, Function<Map<String, Object>, Object>> scripts = org.opensearch.common.collect.Map.of(
+        final Map<String, Function<Map<String, Object>, Object>> scripts = Map.of(
             VALUE_SCRIPT_NAME,
             vars -> ((Number) vars.get("_value")).doubleValue() + 1,
             FIELD_SCRIPT_NAME,
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregatorTests.java
index 2bdc8d88bc366..d4a4245a16628 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentileRanksAggregatorTests.java
@@ -36,10 +36,10 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregatorTests.java
index 50415dc10df7e..2bad6895e3fda 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/TDigestPercentilesAggregatorTests.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorTests.java
index 7dc80ab6f4a7b..c355f0078108b 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsAggregatorTests.java
@@ -40,7 +40,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.queryparser.classic.QueryParser;
 import org.apache.lucene.search.BooleanClause.Occur;
@@ -51,8 +50,9 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.IdFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsTests.java
index 33314d05a76e9..52073cb1cc0c3 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/TopHitsTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.metrics;
 
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.AggregationInitializationException;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.BaseAggregationTestCase;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorTests.java
index 590c927a44fe0..9babdbe78bf14 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/ValueCountAggregatorTests.java
@@ -41,10 +41,10 @@
 import org.apache.lucene.document.SortedDocValuesField;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.SortedSetDocValuesField;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.geo.GeoPoint;
@@ -428,6 +428,8 @@ private static MappedFieldType createMappedFieldType(String name, ValueType valu
             case NUMERIC:
             case LONG:
                 return new NumberFieldMapper.NumberFieldType(name, NumberFieldMapper.NumberType.LONG);
+            case UNSIGNED_LONG:
+                return new NumberFieldMapper.NumberFieldType(name, NumberFieldMapper.NumberType.UNSIGNED_LONG);
             case DATE:
                 return new DateFieldMapper.DateFieldType(name);
             case IP:
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorTests.java
index 844f05f1d2208..8d5992e15d983 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/WeightedAvgAggregatorTests.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.DocValuesFieldExistsQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/metrics/weighted_avg/WeightedAvgAggregationBuilderTests.java b/server/src/test/java/org/opensearch/search/aggregations/metrics/weighted_avg/WeightedAvgAggregationBuilderTests.java
index b5208c6f3cb51..9032fbb456e9d 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/metrics/weighted_avg/WeightedAvgAggregationBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/metrics/weighted_avg/WeightedAvgAggregationBuilderTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.aggregations.metrics.weighted_avg;
 
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.aggregations.AggregatorFactories;
 import org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/AvgBucketAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/AvgBucketAggregatorTests.java
index a5779d4a289f8..3073cb6d35ddf 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/AvgBucketAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/AvgBucketAggregatorTests.java
@@ -36,11 +36,11 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketHelpersTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketHelpersTests.java
index 7cf4dbdfa38db..b6cf355c098e5 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketHelpersTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketHelpersTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregationExecutionException;
 import org.opensearch.search.aggregations.Aggregations;
 import org.opensearch.search.aggregations.InternalMultiBucketAggregation;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptAggregatorTests.java
index a1ff2a40d0404..39eac127918de 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptAggregatorTests.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptTests.java
index 116beb95a61b2..723f151a8b927 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/BucketScriptTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 import org.opensearch.search.aggregations.BasePipelineAggregationTestCase;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/CumulativeSumAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/CumulativeSumAggregatorTests.java
index fdd898b8fbc4c..17846234a09d1 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/CumulativeSumAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/CumulativeSumAggregatorTests.java
@@ -37,12 +37,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.index.mapper.DateFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/DerivativeAggregatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/DerivativeAggregatorTests.java
index 88628cd44c721..6f94772303158 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/DerivativeAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/DerivativeAggregatorTests.java
@@ -36,11 +36,11 @@
 import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.search.SearchPhaseExecutionException;
 import org.opensearch.common.CheckedConsumer;
@@ -60,8 +60,8 @@
 import org.opensearch.search.aggregations.metrics.StatsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.Sum;
 import org.opensearch.search.aggregations.metrics.SumAggregationBuilder;
-import org.opensearch.search.aggregations.support.AggregationPath;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
+import org.opensearch.search.aggregations.support.AggregationPath;
 
 import java.io.IOException;
 import java.util.List;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketTests.java
index aa07388b4dd1b..7602053bb1ed6 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/ExtendedStatsBucketTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/GapPolicyTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/GapPolicyTests.java
index 0eb064079334c..5e78bff3530b7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/GapPolicyTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/GapPolicyTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.io.stream.AbstractWriteableEnumTestCase;
+import org.opensearch.core.common.ParsingException;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucketTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucketTests.java
index b80a9d6fdbe83..e6e7b4f228ed3 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucketTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/InternalPercentilesBucketTests.java
@@ -32,10 +32,9 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.Aggregation.CommonFields;
 import org.opensearch.search.aggregations.ParsedAggregation;
@@ -192,7 +191,7 @@ public void testEmptyRanksXContent() throws IOException {
                 + "}";
         }
 
-        assertThat(Strings.toString(builder), equalTo(expected));
+        assertThat(builder.toString(), equalTo(expected));
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovAvgTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovAvgTests.java
index eb07138b7bff3..958dc3082df71 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovAvgTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovAvgTests.java
@@ -32,18 +32,18 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import static java.util.Collections.emptyList;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.nullValue;
-
-import java.io.IOException;
-
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.search.aggregations.BasePipelineAggregationTestCase;
 import org.opensearch.search.aggregations.PipelineAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
 import org.opensearch.search.aggregations.pipeline.HoltWintersModel.SeasonalityType;
 
+import java.io.IOException;
+
+import static java.util.Collections.emptyList;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+
 public class MovAvgTests extends BasePipelineAggregationTestCase<MovAvgPipelineAggregationBuilder> {
 
     @Override
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovFnAggrgatorTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovFnAggrgatorTests.java
index d841625272828..3ae00efaa6da3 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovFnAggrgatorTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/MovFnAggrgatorTests.java
@@ -38,11 +38,11 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateFormatters;
 import org.opensearch.index.mapper.DateFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketTests.java b/server/src/test/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketTests.java
index 3a19065a5806d..2a382d72059e7 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/pipeline/PercentilesBucketTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.aggregations.pipeline;
 
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.aggregations.AggregationBuilder;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/CoreValuesSourceTypeTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/CoreValuesSourceTypeTests.java
index b6c8f6d8b0d67..2c32d37534b4f 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/CoreValuesSourceTypeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/CoreValuesSourceTypeTests.java
@@ -43,6 +43,7 @@ public void testFromString() {
         assertThat(CoreValuesSourceType.fromString("bytes"), equalTo(CoreValuesSourceType.BYTES));
         assertThat(CoreValuesSourceType.fromString("geopoint"), equalTo(CoreValuesSourceType.GEOPOINT));
         assertThat(CoreValuesSourceType.fromString("range"), equalTo(CoreValuesSourceType.RANGE));
+        assertThat(CoreValuesSourceType.fromString("geo_shape"), equalTo(CoreValuesSourceType.GEO_SHAPE));
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> CoreValuesSourceType.fromString("does_not_exist"));
         assertThat(
             e.getMessage(),
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/IncludeExcludeTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/IncludeExcludeTests.java
index d84812557ab18..f223648de6ef4 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/IncludeExcludeTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/IncludeExcludeTests.java
@@ -36,12 +36,12 @@
 import org.apache.lucene.index.SortedSetDocValues;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.LongBitSet;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.AbstractSortedSetDocValues;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
@@ -53,6 +53,7 @@
 import java.util.TreeSet;
 
 public class IncludeExcludeTests extends OpenSearchTestCase {
+
     public void testEmptyTermsWithOrds() throws IOException {
         IncludeExclude inexcl = new IncludeExclude(new TreeSet<>(Collections.singleton(new BytesRef("foo"))), null);
         OrdinalsFilter filter = inexcl.convertToOrdinalsFilter(DocValueFormat.RAW);
@@ -97,6 +98,10 @@ public long getValueCount() {
                 return 1;
             }
 
+            @Override
+            public int docValueCount() {
+                return 1;
+            }
         };
         IncludeExclude inexcl = new IncludeExclude(new TreeSet<>(Collections.singleton(new BytesRef("foo"))), null);
         OrdinalsFilter filter = inexcl.convertToOrdinalsFilter(DocValueFormat.RAW);
@@ -213,7 +218,7 @@ public void testRegexExclude() throws IOException {
 
     // Serializes/deserializes an IncludeExclude statement with a single clause
     private IncludeExclude serialize(IncludeExclude incExc, ParseField field) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -259,7 +264,7 @@ public void testRegexIncludeAndExclude() throws IOException {
     // Serializes/deserializes the IncludeExclude statement with include AND
     // exclude clauses
     private IncludeExclude serializeMixedRegex(IncludeExclude incExc) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/MissingValuesTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/MissingValuesTests.java
index 598c1323fc13f..c44e0fcca7584 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/MissingValuesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/MissingValuesTests.java
@@ -37,8 +37,8 @@
 
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.index.SortedSetDocValues;
-import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.index.fielddata.AbstractSortedNumericDocValues;
 import org.opensearch.index.fielddata.AbstractSortedSetDocValues;
@@ -155,6 +155,11 @@ public long nextOrd() {
                     return NO_MORE_ORDS;
                 }
             }
+
+            @Override
+            public int docValueCount() {
+                return ords[doc].length;
+            }
         };
 
         final BytesRef existingMissing = RandomPicks.randomFrom(random(), values);
@@ -257,6 +262,11 @@ public BytesRef lookupOrd(long ord) throws IOException {
                 return values[Math.toIntExact(ord)];
             }
 
+            @Override
+            public int docValueCount() {
+                throw new UnsupportedOperationException();
+            }
+
             @Override
             public long getValueCount() {
                 return values.length;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfigTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfigTests.java
new file mode 100644
index 0000000000000..62e3cf2fac479
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/MultiTermsValuesSourceConfigTests.java
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.support;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.script.Script;
+import org.opensearch.search.SearchModule;
+import org.opensearch.test.AbstractSerializingTestCase;
+
+import java.io.IOException;
+import java.time.ZoneId;
+import java.util.Collections;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class MultiTermsValuesSourceConfigTests extends AbstractSerializingTestCase<MultiTermsValuesSourceConfig> {
+
+    @Override
+    protected MultiTermsValuesSourceConfig doParseInstance(XContentParser parser) throws IOException {
+        return MultiTermsValuesSourceConfig.PARSER.apply(true, true, true, true).apply(parser, null).build();
+    }
+
+    @Override
+    protected MultiTermsValuesSourceConfig createTestInstance() {
+        String field = randomAlphaOfLength(10);
+        Object missing = randomBoolean() ? randomAlphaOfLength(10) : null;
+        ZoneId timeZone = randomBoolean() ? randomZone() : null;
+        Script script = randomBoolean() ? new Script(randomAlphaOfLength(10)) : null;
+        return new MultiTermsValuesSourceConfig.Builder().setFieldName(field)
+            .setMissing(missing)
+            .setScript(script)
+            .setTimeZone(timeZone)
+            .build();
+    }
+
+    @Override
+    protected Writeable.Reader<MultiTermsValuesSourceConfig> instanceReader() {
+        return MultiTermsValuesSourceConfig::new;
+    }
+
+    public void testMissingFieldScript() {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new MultiTermsValuesSourceConfig.Builder().build());
+        assertThat(e.getMessage(), equalTo("[field] and [script] cannot both be null.  Please specify one or the other."));
+    }
+
+    @Override
+    protected NamedWriteableRegistry getNamedWriteableRegistry() {
+        return new NamedWriteableRegistry(new SearchModule(Settings.EMPTY, Collections.emptyList()).getNamedWriteables());
+    }
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        return new NamedXContentRegistry(new SearchModule(Settings.EMPTY, Collections.emptyList()).getNamedXContents());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfigTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfigTests.java
index b88d471704211..40242e6711d85 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfigTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/MultiValuesSourceFieldConfigTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.aggregations.support;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.script.Script;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/ScriptValuesTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/ScriptValuesTests.java
index 98e4e8f881b1b..9eb90f2358f98 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/ScriptValuesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/ScriptValuesTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.search.aggregations.support;
 
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
-import java.util.Collections;
+
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.util.BytesRef;
@@ -47,6 +47,7 @@
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
 
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceConfigTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceConfigTests.java
index f866d817a7c43..33d9a63f61a35 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceConfigTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceConfigTests.java
@@ -40,7 +40,6 @@
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.fielddata.SortedBinaryDocValues;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 
@@ -310,25 +309,6 @@ public void testUnmappedBoolean() throws Exception {
         }
     }
 
-    public void testTypeFieldDeprecation() {
-        IndexService indexService = createIndex("index", Settings.EMPTY, "type");
-        try (Engine.Searcher searcher = indexService.getShard(0).acquireSearcher("test")) {
-            QueryShardContext context = indexService.newQueryShardContext(0, searcher, () -> 42L, null);
-
-            ValuesSourceConfig config = ValuesSourceConfig.resolve(
-                context,
-                null,
-                TypeFieldMapper.NAME,
-                null,
-                null,
-                null,
-                null,
-                CoreValuesSourceType.BYTES
-            );
-            assertWarnings(TypeFieldMapper.TYPES_DEPRECATION_MESSAGE);
-        }
-    }
-
     public void testFieldAlias() throws Exception {
         IndexService indexService = createIndex("index", Settings.EMPTY, "type", "field", "type=keyword", "alias", "type=alias,path=field");
         client().prepareIndex("index").setId("1").setSource("field", "value").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
diff --git a/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceRegistryTests.java b/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceRegistryTests.java
index 128030eec735b..aa7852e12cf73 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceRegistryTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/support/ValuesSourceRegistryTests.java
@@ -36,10 +36,11 @@
 import org.opensearch.script.AggregationScript;
 import org.opensearch.search.aggregations.bucket.histogram.HistogramAggregatorSupplier;
 import org.opensearch.test.OpenSearchTestCase;
-import org.mockito.Mockito;
 
 import java.util.Collections;
 
+import org.mockito.Mockito;
+
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
diff --git a/server/src/test/java/org/opensearch/search/backpressure/SearchBackpressureServiceTests.java b/server/src/test/java/org/opensearch/search/backpressure/SearchBackpressureServiceTests.java
new file mode 100644
index 0000000000000..f0d930c4c3acb
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/SearchBackpressureServiceTests.java
@@ -0,0 +1,405 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+import org.opensearch.Version;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.search.backpressure.settings.SearchBackpressureMode;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.search.backpressure.stats.SearchBackpressureStats;
+import org.opensearch.search.backpressure.stats.SearchShardTaskStats;
+import org.opensearch.search.backpressure.stats.SearchTaskStats;
+import org.opensearch.search.backpressure.trackers.NodeDuressTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+import org.opensearch.tasks.TaskCancellationService;
+import org.opensearch.tasks.TaskManager;
+import org.opensearch.tasks.TaskResourceTrackingService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.LongSupplier;
+
+import static org.opensearch.search.backpressure.SearchBackpressureTestHelpers.createMockTaskWithResourceStats;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class SearchBackpressureServiceTests extends OpenSearchTestCase {
+    MockTransportService transportService;
+    TaskManager taskManager;
+    ThreadPool threadPool;
+
+    @Before
+    public void setup() {
+        threadPool = new TestThreadPool(getClass().getName());
+        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, NoopTracer.INSTANCE);
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        taskManager = transportService.getTaskManager();
+        taskManager.setTaskCancellationService(new TaskCancellationService(transportService));
+    }
+
+    @After
+    public void cleanup() {
+        transportService.close();
+        ThreadPool.terminate(threadPool, 5, TimeUnit.SECONDS);
+    }
+
+    public void testIsNodeInDuress() {
+        TaskResourceTrackingService mockTaskResourceTrackingService = mock(TaskResourceTrackingService.class);
+
+        AtomicReference<Double> cpuUsage = new AtomicReference<>();
+        AtomicReference<Double> heapUsage = new AtomicReference<>();
+        NodeDuressTracker cpuUsageTracker = new NodeDuressTracker(() -> cpuUsage.get() >= 0.5);
+        NodeDuressTracker heapUsageTracker = new NodeDuressTracker(() -> heapUsage.get() >= 0.5);
+
+        SearchBackpressureSettings settings = new SearchBackpressureSettings(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        SearchBackpressureService service = new SearchBackpressureService(
+            settings,
+            mockTaskResourceTrackingService,
+            threadPool,
+            System::nanoTime,
+            List.of(cpuUsageTracker, heapUsageTracker),
+            Collections.emptyList(),
+            Collections.emptyList(),
+            taskManager
+        );
+
+        // Node not in duress.
+        cpuUsage.set(0.0);
+        heapUsage.set(0.0);
+        assertFalse(service.isNodeInDuress());
+
+        // Node in duress; but not for many consecutive data points.
+        cpuUsage.set(1.0);
+        heapUsage.set(1.0);
+        assertFalse(service.isNodeInDuress());
+
+        // Node in duress for consecutive data points.
+        assertFalse(service.isNodeInDuress());
+        assertTrue(service.isNodeInDuress());
+
+        // Node not in duress anymore.
+        cpuUsage.set(0.0);
+        heapUsage.set(0.0);
+        assertFalse(service.isNodeInDuress());
+    }
+
+    public void testTrackerStateUpdateOnSearchTaskCompletion() {
+        TaskResourceTrackingService mockTaskResourceTrackingService = mock(TaskResourceTrackingService.class);
+        LongSupplier mockTimeNanosSupplier = () -> TimeUnit.SECONDS.toNanos(1234);
+        TaskResourceUsageTracker mockTaskResourceUsageTracker = mock(TaskResourceUsageTracker.class);
+
+        SearchBackpressureSettings settings = new SearchBackpressureSettings(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        SearchBackpressureService service = new SearchBackpressureService(
+            settings,
+            mockTaskResourceTrackingService,
+            threadPool,
+            mockTimeNanosSupplier,
+            Collections.emptyList(),
+            List.of(mockTaskResourceUsageTracker),
+            Collections.emptyList(),
+            taskManager
+        );
+
+        for (int i = 0; i < 100; i++) {
+            // service.onTaskCompleted(new SearchTask(1, "test", "test", () -> "Test", TaskId.EMPTY_TASK_ID, new HashMap<>()));
+            service.onTaskCompleted(createMockTaskWithResourceStats(SearchTask.class, 100, 200));
+        }
+        assertEquals(100, service.getSearchBackpressureState(SearchTask.class).getCompletionCount());
+        verify(mockTaskResourceUsageTracker, times(100)).update(any());
+    }
+
+    public void testTrackerStateUpdateOnSearchShardTaskCompletion() {
+        TaskResourceTrackingService mockTaskResourceTrackingService = mock(TaskResourceTrackingService.class);
+        LongSupplier mockTimeNanosSupplier = () -> TimeUnit.SECONDS.toNanos(1234);
+        TaskResourceUsageTracker mockTaskResourceUsageTracker = mock(TaskResourceUsageTracker.class);
+
+        SearchBackpressureSettings settings = new SearchBackpressureSettings(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        SearchBackpressureService service = new SearchBackpressureService(
+            settings,
+            mockTaskResourceTrackingService,
+            threadPool,
+            mockTimeNanosSupplier,
+            Collections.emptyList(),
+            Collections.emptyList(),
+            List.of(mockTaskResourceUsageTracker),
+            taskManager
+        );
+
+        // Record task completions to update the tracker state. Tasks other than SearchTask & SearchShardTask are ignored.
+        service.onTaskCompleted(createMockTaskWithResourceStats(CancellableTask.class, 100, 200));
+        for (int i = 0; i < 100; i++) {
+            service.onTaskCompleted(createMockTaskWithResourceStats(SearchShardTask.class, 100, 200));
+        }
+        assertEquals(100, service.getSearchBackpressureState(SearchShardTask.class).getCompletionCount());
+        verify(mockTaskResourceUsageTracker, times(100)).update(any());
+    }
+
+    public void testSearchTaskInFlightCancellation() {
+        TaskManager mockTaskManager = spy(taskManager);
+        TaskResourceTrackingService mockTaskResourceTrackingService = mock(TaskResourceTrackingService.class);
+        AtomicLong mockTime = new AtomicLong(0);
+        LongSupplier mockTimeNanosSupplier = mockTime::get;
+        NodeDuressTracker mockNodeDuressTracker = new NodeDuressTracker(() -> true);
+
+        TaskResourceUsageTracker mockTaskResourceUsageTracker = getMockedTaskResourceUsageTracker();
+
+        // Mocking 'settings' with predictable rate limiting thresholds.
+        SearchBackpressureSettings settings = getBackpressureSettings("enforced", 0.1, 0.003, 5.0);
+
+        SearchBackpressureService service = new SearchBackpressureService(
+            settings,
+            mockTaskResourceTrackingService,
+            threadPool,
+            mockTimeNanosSupplier,
+            List.of(mockNodeDuressTracker),
+            List.of(mockTaskResourceUsageTracker),
+            Collections.emptyList(),
+            mockTaskManager
+        );
+
+        // Run two iterations so that node is marked 'in duress' from the third iteration onwards.
+        service.doRun();
+        service.doRun();
+
+        // Mocking 'settings' with predictable totalHeapBytesThreshold so that cancellation logic doesn't get skipped.
+        long taskHeapUsageBytes = 500;
+        SearchTaskSettings searchTaskSettings = mock(SearchTaskSettings.class);
+        // setting the total heap percent threshold to minimum so that circuit does not break in SearchBackpressureService
+        when(searchTaskSettings.getTotalHeapPercentThreshold()).thenReturn(0.0);
+        when(settings.getSearchTaskSettings()).thenReturn(searchTaskSettings);
+
+        // Create a mix of low and high resource usage SearchTasks (50 low + 25 high resource usage tasks).
+        Map<Long, Task> activeSearchTasks = new HashMap<>();
+        for (long i = 0; i < 75; i++) {
+            if (i % 3 == 0) {
+                activeSearchTasks.put(i, createMockTaskWithResourceStats(SearchTask.class, 500, taskHeapUsageBytes));
+            } else {
+                activeSearchTasks.put(i, createMockTaskWithResourceStats(SearchTask.class, 100, taskHeapUsageBytes));
+            }
+        }
+        doReturn(activeSearchTasks).when(mockTaskResourceTrackingService).getResourceAwareTasks();
+
+        // There are 25 SearchTasks eligible for cancellation but only 5 will be cancelled (burst limit).
+        service.doRun();
+        verify(mockTaskManager, times(5)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(1, service.getSearchBackpressureState(SearchTask.class).getLimitReachedCount());
+
+        // If the clock or completed task count haven't made sufficient progress, we'll continue to be rate-limited.
+        service.doRun();
+        verify(mockTaskManager, times(5)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(2, service.getSearchBackpressureState(SearchTask.class).getLimitReachedCount());
+
+        // Fast-forward the clock by ten second to replenish some tokens.
+        // This will add 50 tokens (time delta * rate) to 'rateLimitPerTime' but it will cancel only 5 tasks (burst limit).
+        mockTime.addAndGet(TimeUnit.SECONDS.toNanos(10));
+        service.doRun();
+        verify(mockTaskManager, times(10)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(3, service.getSearchBackpressureState(SearchTask.class).getLimitReachedCount());
+
+        // Verify search backpressure stats.
+        SearchBackpressureStats expectedStats = new SearchBackpressureStats(
+            new SearchTaskStats(10, 3, Map.of(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER, new MockStats(10))),
+            new SearchShardTaskStats(0, 0, Collections.emptyMap()),
+            SearchBackpressureMode.ENFORCED
+        );
+        SearchBackpressureStats actualStats = service.nodeStats();
+        assertEquals(expectedStats, actualStats);
+    }
+
+    public void testSearchShardTaskInFlightCancellation() {
+        TaskManager mockTaskManager = spy(taskManager);
+        TaskResourceTrackingService mockTaskResourceTrackingService = mock(TaskResourceTrackingService.class);
+        AtomicLong mockTime = new AtomicLong(0);
+        LongSupplier mockTimeNanosSupplier = mockTime::get;
+        NodeDuressTracker mockNodeDuressTracker = new NodeDuressTracker(() -> true);
+
+        TaskResourceUsageTracker mockTaskResourceUsageTracker = getMockedTaskResourceUsageTracker();
+
+        // Mocking 'settings' with predictable rate limiting thresholds.
+        SearchBackpressureSettings settings = getBackpressureSettings("enforced", 0.1, 0.003, 10.0);
+
+        SearchBackpressureService service = new SearchBackpressureService(
+            settings,
+            mockTaskResourceTrackingService,
+            threadPool,
+            mockTimeNanosSupplier,
+            List.of(mockNodeDuressTracker),
+            Collections.emptyList(),
+            List.of(mockTaskResourceUsageTracker),
+            mockTaskManager
+        );
+
+        // Run two iterations so that node is marked 'in duress' from the third iteration onwards.
+        service.doRun();
+        service.doRun();
+
+        // Mocking 'settings' with predictable totalHeapBytesThreshold so that cancellation logic doesn't get skipped.
+        long taskHeapUsageBytes = 500;
+        SearchShardTaskSettings searchShardTaskSettings = mock(SearchShardTaskSettings.class);
+        // setting the total heap percent threshold to minimum so that circuit does not break in SearchBackpressureService
+        when(searchShardTaskSettings.getTotalHeapPercentThreshold()).thenReturn(0.0);
+        when(settings.getSearchShardTaskSettings()).thenReturn(searchShardTaskSettings);
+
+        // Create a mix of low and high resource usage tasks (60 low + 15 high resource usage tasks).
+        Map<Long, Task> activeSearchShardTasks = new HashMap<>();
+        for (long i = 0; i < 75; i++) {
+            if (i % 5 == 0) {
+                activeSearchShardTasks.put(i, createMockTaskWithResourceStats(SearchShardTask.class, 500, taskHeapUsageBytes));
+            } else {
+                activeSearchShardTasks.put(i, createMockTaskWithResourceStats(SearchShardTask.class, 100, taskHeapUsageBytes));
+            }
+        }
+        doReturn(activeSearchShardTasks).when(mockTaskResourceTrackingService).getResourceAwareTasks();
+
+        // There are 15 SearchShardTasks eligible for cancellation but only 10 will be cancelled (burst limit).
+        service.doRun();
+        verify(mockTaskManager, times(10)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(1, service.getSearchBackpressureState(SearchShardTask.class).getLimitReachedCount());
+
+        // If the clock or completed task count haven't made sufficient progress, we'll continue to be rate-limited.
+        service.doRun();
+        verify(mockTaskManager, times(10)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(2, service.getSearchBackpressureState(SearchShardTask.class).getLimitReachedCount());
+
+        // Simulate task completion to replenish some tokens.
+        // This will add 2 tokens (task count delta * cancellationRatio) to 'rateLimitPerTaskCompletion'.
+        for (int i = 0; i < 20; i++) {
+            service.onTaskCompleted(createMockTaskWithResourceStats(SearchShardTask.class, 100, taskHeapUsageBytes));
+        }
+        service.doRun();
+        verify(mockTaskManager, times(12)).cancelTaskAndDescendants(any(), anyString(), anyBoolean(), any());
+        assertEquals(3, service.getSearchBackpressureState(SearchShardTask.class).getLimitReachedCount());
+
+        // Verify search backpressure stats.
+        SearchBackpressureStats expectedStats = new SearchBackpressureStats(
+            new SearchTaskStats(0, 0, Collections.emptyMap()),
+            new SearchShardTaskStats(12, 3, Map.of(TaskResourceUsageTrackerType.CPU_USAGE_TRACKER, new MockStats(12))),
+            SearchBackpressureMode.ENFORCED
+        );
+        SearchBackpressureStats actualStats = service.nodeStats();
+        assertEquals(expectedStats, actualStats);
+    }
+
+    private SearchBackpressureSettings getBackpressureSettings(String mode, double ratio, double rate, double burst) {
+        return spy(
+            new SearchBackpressureSettings(
+                Settings.builder().put(SearchBackpressureSettings.SETTING_MODE.getKey(), mode).build(),
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            )
+        );
+    }
+
+    private TaskResourceUsageTracker getMockedTaskResourceUsageTracker() {
+        return new TaskResourceUsageTracker() {
+            @Override
+            public String name() {
+                return TaskResourceUsageTrackerType.CPU_USAGE_TRACKER.getName();
+            }
+
+            @Override
+            public void update(Task task) {}
+
+            @Override
+            public Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task) {
+                if (task.getTotalResourceStats().getCpuTimeInNanos() < 300) {
+                    return Optional.empty();
+                }
+
+                return Optional.of(new TaskCancellation.Reason("limits exceeded", 5));
+            }
+
+            @Override
+            public Stats stats(List<? extends Task> tasks) {
+                return new MockStats(getCancellations());
+            }
+        };
+    }
+
+    private static class MockStats implements TaskResourceUsageTracker.Stats {
+        private final long cancellationCount;
+
+        public MockStats(long cancellationCount) {
+            this.cancellationCount = cancellationCount;
+        }
+
+        public MockStats(StreamInput in) throws IOException {
+            this(in.readVLong());
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return builder.startObject().field("cancellation_count", cancellationCount).endObject();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeVLong(cancellationCount);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            MockStats mockStats = (MockStats) o;
+            return cancellationCount == mockStats.cancellationCount;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(cancellationCount);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureRenamedSettingsTests.java b/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureRenamedSettingsTests.java
new file mode 100644
index 0000000000000..a0eb05ecaa91d
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureRenamedSettingsTests.java
@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Arrays;
+import java.util.Set;
+
+public class SearchBackpressureRenamedSettingsTests extends OpenSearchTestCase {
+
+    /**
+     * Validate the both settings are known and supported.
+     */
+    public void testOldSettingsExist() {
+        Set<Setting<?>> settings = ClusterSettings.BUILT_IN_CLUSTER_SETTINGS;
+        assertTrue(
+            "Both 'search_backpressure.search_shard_task.cancellation_ratio' and its predecessor should be supported built-in settings",
+            settings.containsAll(
+                Arrays.asList(SearchBackpressureSettings.SETTING_CANCELLATION_RATIO, SearchShardTaskSettings.SETTING_CANCELLATION_RATIO)
+            )
+        );
+
+        assertTrue(
+            "Both 'search_backpressure.search_shard_task.cancellation_rate' and its predecessor should be supported built-in settings",
+            settings.containsAll(
+                Arrays.asList(SearchBackpressureSettings.SETTING_CANCELLATION_RATE, SearchShardTaskSettings.SETTING_CANCELLATION_RATE)
+            )
+        );
+
+        assertTrue(
+            "Both 'search_backpressure.search_shard_task.cancellation_burst' and its predecessor should be supported built-in settings",
+            settings.containsAll(
+                Arrays.asList(SearchBackpressureSettings.SETTING_CANCELLATION_BURST, SearchShardTaskSettings.SETTING_CANCELLATION_BURST)
+            )
+        );
+    }
+
+    /**
+     * Validate the default value of the both settings is the same.
+     */
+    public void testSettingFallback() {
+        assertEquals(
+            SearchBackpressureSettings.SETTING_CANCELLATION_RATIO.get(Settings.EMPTY),
+            SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.get(Settings.EMPTY)
+        );
+
+        assertEquals(
+            SearchBackpressureSettings.SETTING_CANCELLATION_RATE.get(Settings.EMPTY),
+            SearchShardTaskSettings.SETTING_CANCELLATION_RATE.get(Settings.EMPTY)
+        );
+
+        assertEquals(
+            SearchBackpressureSettings.SETTING_CANCELLATION_BURST.get(Settings.EMPTY),
+            SearchShardTaskSettings.SETTING_CANCELLATION_BURST.get(Settings.EMPTY)
+        );
+    }
+
+    /**
+     * Validate the new setting can be configured correctly, and it doesn't impact the old setting.
+     */
+    public void testSettingGetValue() {
+        Settings settings = Settings.builder().put("search_backpressure.search_shard_task.cancellation_ratio", "0.5").build();
+        assertEquals(Double.valueOf(0.5), SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.get(settings));
+        assertEquals(
+            SearchBackpressureSettings.SETTING_CANCELLATION_RATIO.getDefault(Settings.EMPTY),
+            SearchBackpressureSettings.SETTING_CANCELLATION_RATIO.get(settings)
+        );
+    }
+
+    /**
+     * Validate the value of the old setting will be applied to the new setting, if the new setting is not configured.
+     */
+    public void testSettingGetValueWithFallback() {
+        Settings settings = Settings.builder().put("search_backpressure.cancellation_ratio", "0.3").build();
+        assertEquals(Double.valueOf(0.3), SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.get(settings));
+        assertSettingDeprecationsAndWarnings(new Setting<?>[] { SearchBackpressureSettings.SETTING_CANCELLATION_RATIO });
+    }
+
+    /**
+     * Validate the value of the old setting will be ignored, if the new setting is configured.
+     */
+    public void testSettingGetValueWhenBothAreConfigured() {
+        Settings settings = Settings.builder()
+            .put("search_backpressure.search_shard_task.cancellation_ratio", "0.2")
+            .put("search_backpressure.cancellation_ratio", "0.4")
+            .build();
+        assertEquals(Double.valueOf(0.2), SearchShardTaskSettings.SETTING_CANCELLATION_RATIO.get(settings));
+        assertEquals(Double.valueOf(0.4), SearchBackpressureSettings.SETTING_CANCELLATION_RATIO.get(settings));
+        assertSettingDeprecationsAndWarnings(new Setting<?>[] { SearchBackpressureSettings.SETTING_CANCELLATION_RATIO });
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettingsTests.java b/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettingsTests.java
new file mode 100644
index 0000000000000..a02ca3cf877ad
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/settings/SearchBackpressureSettingsTests.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.settings;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class SearchBackpressureSettingsTests extends OpenSearchTestCase {
+
+    /**
+     * Validate proper construction of SearchBackpressureSettings object with a valid mode.
+     */
+    public void testSearchBackpressureSettings() {
+        Settings settings = Settings.builder().put("search_backpressure.mode", "monitor_only").build();
+        ClusterSettings cs = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        SearchBackpressureSettings sbs = new SearchBackpressureSettings(settings, cs);
+        assertEquals(SearchBackpressureMode.MONITOR_ONLY, sbs.getMode());
+        assertEquals(settings, sbs.getSettings());
+        assertEquals(cs, sbs.getClusterSettings());
+    }
+
+    /**
+     * Validate construction of SearchBackpressureSettings object gets rejected
+     * on invalid SearchBackpressureMode value.
+     */
+    public void testSearchBackpressureSettingValidateInvalidMode() {
+        Settings settings = Settings.builder().put("search_backpressure.mode", "foo").build();
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> new SearchBackpressureSettings(settings, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/stats/SearchBackpressureStatsTests.java b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchBackpressureStatsTests.java
new file mode 100644
index 0000000000000..ffbfa054b4837
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchBackpressureStatsTests.java
@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.search.backpressure.settings.SearchBackpressureMode;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+public class SearchBackpressureStatsTests extends AbstractWireSerializingTestCase<SearchBackpressureStats> {
+    @Override
+    protected Writeable.Reader<SearchBackpressureStats> instanceReader() {
+        return SearchBackpressureStats::new;
+    }
+
+    @Override
+    protected SearchBackpressureStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static SearchBackpressureStats randomInstance() {
+        return new SearchBackpressureStats(
+            SearchTaskStatsTests.randomInstance(),
+            SearchShardTaskStatsTests.randomInstance(),
+            randomFrom(SearchBackpressureMode.DISABLED, SearchBackpressureMode.MONITOR_ONLY, SearchBackpressureMode.ENFORCED)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/stats/SearchShardTaskStatsTests.java b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchShardTaskStatsTests.java
new file mode 100644
index 0000000000000..6478fdfff61d4
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchShardTaskStatsTests.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.search.backpressure.trackers.CpuUsageTracker;
+import org.opensearch.search.backpressure.trackers.ElapsedTimeTracker;
+import org.opensearch.search.backpressure.trackers.HeapUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+import java.util.Map;
+
+public class SearchShardTaskStatsTests extends AbstractWireSerializingTestCase<SearchShardTaskStats> {
+    @Override
+    protected Writeable.Reader<SearchShardTaskStats> instanceReader() {
+        return SearchShardTaskStats::new;
+    }
+
+    @Override
+    protected SearchShardTaskStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static SearchShardTaskStats randomInstance() {
+        Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats = Map.of(
+            TaskResourceUsageTrackerType.CPU_USAGE_TRACKER,
+            new CpuUsageTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong()),
+            TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER,
+            new HeapUsageTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong()),
+            TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER,
+            new ElapsedTimeTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong())
+        );
+
+        return new SearchShardTaskStats(randomNonNegativeLong(), randomNonNegativeLong(), resourceUsageTrackerStats);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/stats/SearchTaskStatsTests.java b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchTaskStatsTests.java
new file mode 100644
index 0000000000000..eb33bc1c37b7e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/stats/SearchTaskStatsTests.java
@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.stats;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.search.backpressure.trackers.CpuUsageTracker;
+import org.opensearch.search.backpressure.trackers.ElapsedTimeTracker;
+import org.opensearch.search.backpressure.trackers.HeapUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTrackerType;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+import java.util.Map;
+
+public class SearchTaskStatsTests extends AbstractWireSerializingTestCase<SearchTaskStats> {
+
+    @Override
+    protected Writeable.Reader<SearchTaskStats> instanceReader() {
+        return SearchTaskStats::new;
+    }
+
+    @Override
+    protected SearchTaskStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static SearchTaskStats randomInstance() {
+        Map<TaskResourceUsageTrackerType, TaskResourceUsageTracker.Stats> resourceUsageTrackerStats = Map.of(
+            TaskResourceUsageTrackerType.CPU_USAGE_TRACKER,
+            new CpuUsageTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong()),
+            TaskResourceUsageTrackerType.HEAP_USAGE_TRACKER,
+            new HeapUsageTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong()),
+            TaskResourceUsageTrackerType.ELAPSED_TIME_TRACKER,
+            new ElapsedTimeTracker.Stats(randomNonNegativeLong(), randomNonNegativeLong(), randomNonNegativeLong())
+        );
+
+        return new SearchTaskStats(randomNonNegativeLong(), randomNonNegativeLong(), resourceUsageTrackerStats);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/trackers/CpuUsageTrackerTests.java b/server/src/test/java/org/opensearch/search/backpressure/trackers/CpuUsageTrackerTests.java
new file mode 100644
index 0000000000000..8cdcbc7511bd2
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/trackers/CpuUsageTrackerTests.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Optional;
+
+import static org.opensearch.search.backpressure.SearchBackpressureTestHelpers.createMockTaskWithResourceStats;
+
+public class CpuUsageTrackerTests extends OpenSearchTestCase {
+    private static final SearchBackpressureSettings mockSettings = new SearchBackpressureSettings(
+        Settings.builder()
+            .put(SearchShardTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD.getKey(), 15)  // 15 ms
+            .put(SearchTaskSettings.SETTING_CPU_TIME_MILLIS_THRESHOLD.getKey(), 25)   // 25 ms
+            .build(),
+        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+    );
+
+    public void testSearchTaskEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchTask.class, 100000000, 200);
+        CpuUsageTracker tracker = new CpuUsageTracker(mockSettings.getSearchTaskSettings()::getCpuTimeNanosThreshold);
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(1, reason.get().getCancellationScore());
+        assertEquals("cpu usage exceeded [100ms >= 25ms]", reason.get().getMessage());
+    }
+
+    public void testSearchShardTaskEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchShardTask.class, 200000000, 200);
+        CpuUsageTracker tracker = new CpuUsageTracker(mockSettings.getSearchShardTaskSettings()::getCpuTimeNanosThreshold);
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(1, reason.get().getCancellationScore());
+        assertEquals("cpu usage exceeded [200ms >= 15ms]", reason.get().getMessage());
+    }
+
+    public void testNotEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchShardTask.class, 5000000, 200);
+        CpuUsageTracker tracker = new CpuUsageTracker(mockSettings.getSearchShardTaskSettings()::getCpuTimeNanosThreshold);
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertFalse(reason.isPresent());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTrackerTests.java b/server/src/test/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTrackerTests.java
new file mode 100644
index 0000000000000..921d01e7355a7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/trackers/ElapsedTimeTrackerTests.java
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Optional;
+
+import static org.opensearch.search.backpressure.SearchBackpressureTestHelpers.createMockTaskWithResourceStats;
+
+public class ElapsedTimeTrackerTests extends OpenSearchTestCase {
+
+    private static final SearchBackpressureSettings mockSettings = new SearchBackpressureSettings(
+        Settings.builder()
+            .put(SearchShardTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.getKey(), 100) // 100 ms
+            .put(SearchTaskSettings.SETTING_ELAPSED_TIME_MILLIS_THRESHOLD.getKey(), 150)   // 150 ms
+            .build(),
+        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+    );
+
+    public void testSearchTaskEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchTask.class, 1, 1, 0);
+        ElapsedTimeTracker tracker = new ElapsedTimeTracker(
+            mockSettings.getSearchTaskSettings()::getElapsedTimeNanosThreshold,
+            () -> 150000000
+        );
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(1, reason.get().getCancellationScore());
+        assertEquals("elapsed time exceeded [150ms >= 150ms]", reason.get().getMessage());
+    }
+
+    public void testSearchShardTaskEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 1, 0);
+        ElapsedTimeTracker tracker = new ElapsedTimeTracker(
+            mockSettings.getSearchShardTaskSettings()::getElapsedTimeNanosThreshold,
+            () -> 200000000
+        );
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(1, reason.get().getCancellationScore());
+        assertEquals("elapsed time exceeded [200ms >= 100ms]", reason.get().getMessage());
+    }
+
+    public void testNotEligibleForCancellation() {
+        Task task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 1, 150000000);
+        ElapsedTimeTracker tracker = new ElapsedTimeTracker(
+            mockSettings.getSearchShardTaskSettings()::getElapsedTimeNanosThreshold,
+            () -> 200000000
+        );
+
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertFalse(reason.isPresent());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/trackers/HeapUsageTrackerTests.java b/server/src/test/java/org/opensearch/search/backpressure/trackers/HeapUsageTrackerTests.java
new file mode 100644
index 0000000000000..3950d00b0c8b5
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/trackers/HeapUsageTrackerTests.java
@@ -0,0 +1,159 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.monitor.jvm.JvmStats;
+import org.opensearch.search.backpressure.settings.SearchBackpressureSettings;
+import org.opensearch.search.backpressure.settings.SearchShardTaskSettings;
+import org.opensearch.search.backpressure.settings.SearchTaskSettings;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.tasks.Task;
+import org.opensearch.tasks.TaskCancellation;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+import java.util.Optional;
+
+import static org.opensearch.search.backpressure.SearchBackpressureTestHelpers.createMockTaskWithResourceStats;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+public class HeapUsageTrackerTests extends OpenSearchTestCase {
+    private static final long HEAP_BYTES_THRESHOLD_SEARCH_SHARD_TASK = 100;
+    private static final long HEAP_BYTES_THRESHOLD_SEARCH_TASK = 50;
+    private static final int HEAP_MOVING_AVERAGE_WINDOW_SIZE = 100;
+
+    private static final SearchBackpressureSettings mockSettings = new SearchBackpressureSettings(
+        Settings.builder()
+            .put(SearchTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD.getKey(), 3.0)
+            .put(SearchShardTaskSettings.SETTING_HEAP_VARIANCE_THRESHOLD.getKey(), 2.0)
+            .put(SearchTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.getKey(), HEAP_MOVING_AVERAGE_WINDOW_SIZE)
+            .put(SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE.getKey(), HEAP_MOVING_AVERAGE_WINDOW_SIZE)
+            .build(),
+        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+    );
+
+    public void testSearchTaskEligibleForCancellation() {
+        SearchTaskSettings mockSearchTaskSettings = spy(
+            new SearchTaskSettings(mockSettings.getSettings(), mockSettings.getClusterSettings())
+        );
+        // setting the heap percent threshold to minimum
+        when(mockSearchTaskSettings.getHeapPercentThreshold()).thenReturn(0.0);
+        HeapUsageTracker tracker = spy(
+            new HeapUsageTracker(
+                mockSearchTaskSettings::getHeapVarianceThreshold,
+                mockSearchTaskSettings::getHeapPercentThreshold,
+                mockSearchTaskSettings.getHeapMovingAverageWindowSize(),
+                mockSettings.getClusterSettings(),
+                SearchTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE
+            )
+        );
+        Task task = createMockTaskWithResourceStats(SearchTask.class, 1, 50);
+
+        // Record enough observations to make the moving average 'ready'.
+        for (int i = 0; i < HEAP_MOVING_AVERAGE_WINDOW_SIZE; i++) {
+            tracker.update(task);
+        }
+
+        // Task that has heap usage >= heapBytesThreshold and (movingAverage * heapVariance).
+        task = createMockTaskWithResourceStats(SearchTask.class, 1, 300);
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(6, reason.get().getCancellationScore());
+        assertEquals("heap usage exceeded [300b >= 150b]", reason.get().getMessage());
+    }
+
+    public void testSearchShardTaskEligibleForCancellation() {
+        SearchShardTaskSettings mockSearchShardTaskSettings = spy(
+            new SearchShardTaskSettings(mockSettings.getSettings(), mockSettings.getClusterSettings())
+        );
+        // setting the heap percent threshold to minimum
+        when(mockSearchShardTaskSettings.getHeapPercentThreshold()).thenReturn(0.0);
+        HeapUsageTracker tracker = spy(
+            new HeapUsageTracker(
+                mockSearchShardTaskSettings::getHeapVarianceThreshold,
+                mockSearchShardTaskSettings::getHeapPercentThreshold,
+                mockSearchShardTaskSettings.getHeapMovingAverageWindowSize(),
+                mockSettings.getClusterSettings(),
+                SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE
+            )
+        );
+        Task task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 50);
+
+        // Record enough observations to make the moving average 'ready'.
+        for (int i = 0; i < HEAP_MOVING_AVERAGE_WINDOW_SIZE; i++) {
+            tracker.update(task);
+        }
+
+        // Task that has heap usage >= heapBytesThreshold and (movingAverage * heapVariance).
+        task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 200);
+        Optional<TaskCancellation.Reason> reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertTrue(reason.isPresent());
+        assertEquals(4, reason.get().getCancellationScore());
+        assertEquals("heap usage exceeded [200b >= 100b]", reason.get().getMessage());
+    }
+
+    public void testNotEligibleForCancellation() {
+        Task task;
+        Optional<TaskCancellation.Reason> reason;
+        SearchShardTaskSettings mockSearchShardTaskSettings = spy(
+            new SearchShardTaskSettings(mockSettings.getSettings(), mockSettings.getClusterSettings())
+        );
+        // setting the heap percent threshold to minimum
+        when(mockSearchShardTaskSettings.getHeapPercentThreshold()).thenReturn(0.0);
+        HeapUsageTracker tracker = spy(
+            new HeapUsageTracker(
+                mockSearchShardTaskSettings::getHeapVarianceThreshold,
+                mockSearchShardTaskSettings::getHeapPercentThreshold,
+                mockSearchShardTaskSettings.getHeapMovingAverageWindowSize(),
+                mockSettings.getClusterSettings(),
+                SearchShardTaskSettings.SETTING_HEAP_MOVING_AVERAGE_WINDOW_SIZE
+            )
+        );
+
+        // Task with heap usage < heapBytesThreshold.
+        task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 99);
+
+        // Not enough observations.
+        reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertFalse(reason.isPresent());
+
+        // Record enough observations to make the moving average 'ready'.
+        for (int i = 0; i < HEAP_MOVING_AVERAGE_WINDOW_SIZE; i++) {
+            tracker.update(task);
+        }
+
+        // Task with heap usage < heapBytesThreshold should not be cancelled.
+        reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertFalse(reason.isPresent());
+
+        // Task with heap usage between heapBytesThreshold and (movingAverage * heapVariance) should not be cancelled.
+        double allowedHeapUsage = 99.0 * 2.0;
+        task = createMockTaskWithResourceStats(SearchShardTask.class, 1, randomLongBetween(99, (long) allowedHeapUsage - 1));
+        reason = tracker.checkAndMaybeGetCancellationReason(task);
+        assertFalse(reason.isPresent());
+    }
+
+    public void testIsHeapUsageDominatedBySearch() {
+        assumeTrue("Skip the test if the hardware doesn't support heap usage tracking", HeapUsageTracker.isHeapTrackingSupported());
+
+        // task with 1 byte of heap usage so that it does not breach the threshold
+        CancellableTask task = createMockTaskWithResourceStats(SearchShardTask.class, 1, 1);
+        assertFalse(HeapUsageTracker.isHeapUsageDominatedBySearch(List.of(task), 0.5));
+
+        long totalHeap = JvmStats.jvmStats().getMem().getHeapMax().getBytes();
+        // task with heap usage of [totalHeap - 1] so that it breaches the threshold
+        task = createMockTaskWithResourceStats(SearchShardTask.class, 1, totalHeap - 1);
+        assertTrue(HeapUsageTracker.isHeapUsageDominatedBySearch(List.of(task), 0.5));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/backpressure/trackers/NodeDuressTrackerTests.java b/server/src/test/java/org/opensearch/search/backpressure/trackers/NodeDuressTrackerTests.java
new file mode 100644
index 0000000000000..472ba95566523
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/backpressure/trackers/NodeDuressTrackerTests.java
@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure.trackers;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+public class NodeDuressTrackerTests extends OpenSearchTestCase {
+
+    public void testNodeDuressTracker() {
+        AtomicReference<Double> cpuUsage = new AtomicReference<>(0.0);
+        NodeDuressTracker tracker = new NodeDuressTracker(() -> cpuUsage.get() >= 0.5);
+
+        // Node not in duress.
+        assertEquals(0, tracker.check());
+
+        // Node in duress; the streak must keep increasing.
+        cpuUsage.set(0.7);
+        assertEquals(1, tracker.check());
+        assertEquals(2, tracker.check());
+        assertEquals(3, tracker.check());
+
+        // Node not in duress anymore.
+        cpuUsage.set(0.3);
+        assertEquals(0, tracker.check());
+        assertEquals(0, tracker.check());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/builder/SearchSourceBuilderTests.java b/server/src/test/java/org/opensearch/search/builder/SearchSourceBuilderTests.java
index 66b18bc42ad50..3d0e5c3eaf1c0 100644
--- a/server/src/test/java/org/opensearch/search/builder/SearchSourceBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/builder/SearchSourceBuilderTests.java
@@ -33,19 +33,20 @@
 package org.opensearch.search.builder;
 
 import com.fasterxml.jackson.core.JsonParseException;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
+
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -57,8 +58,8 @@
 import org.opensearch.search.sort.FieldSortBuilder;
 import org.opensearch.search.sort.ScoreSortBuilder;
 import org.opensearch.search.sort.SortOrder;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.Map;
@@ -72,7 +73,7 @@ public class SearchSourceBuilderTests extends AbstractSearchTestCase {
 
     public void testFromXContent() throws IOException {
         SearchSourceBuilder testSearchSourceBuilder = createSearchSourceBuilder();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -425,7 +426,7 @@ public void testToXContent() throws IOException {
         XContentType xContentType = randomFrom(XContentType.values());
         {
             SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
-            XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType);
             searchSourceBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
             BytesReference source = BytesReference.bytes(builder);
             Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false, xContentType).v2();
@@ -434,7 +435,7 @@ public void testToXContent() throws IOException {
         {
             SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
             searchSourceBuilder.query(RandomQueryBuilder.createQuery(random()));
-            XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType);
             searchSourceBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
             BytesReference source = BytesReference.bytes(builder);
             Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false, xContentType).v2();
@@ -448,7 +449,7 @@ public void testToXContentWithPointInTime() throws IOException {
         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
         TimeValue keepAlive = randomBoolean() ? TimeValue.timeValueHours(1) : null;
         searchSourceBuilder.pointInTimeBuilder(new PointInTimeBuilder("id").setKeepAlive(keepAlive));
-        XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType);
         searchSourceBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
         BytesReference bytes = BytesReference.bytes(builder);
         Map<String, Object> sourceAsMap = XContentHelper.convertToMap(bytes, false, xContentType).v2();
diff --git a/server/src/test/java/org/opensearch/search/collapse/CollapseBuilderTests.java b/server/src/test/java/org/opensearch/search/collapse/CollapseBuilderTests.java
index 88060b645fb90..fff27ecf34509 100644
--- a/server/src/test/java/org/opensearch/search/collapse/CollapseBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/collapse/CollapseBuilderTests.java
@@ -31,18 +31,18 @@
 
 package org.opensearch.search.collapse;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.Directory;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.NumberFieldMapper;
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/FetchSourcePhaseTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/FetchSourcePhaseTests.java
index 92b398f3030e1..6159e4a5c79b1 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/FetchSourcePhaseTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/FetchSourcePhaseTests.java
@@ -34,10 +34,10 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.memory.MemoryIndex;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.fetch.FetchContext;
 import org.opensearch.search.fetch.FetchSubPhase.HitContext;
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/FieldFetcherTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/FieldFetcherTests.java
index 8147d1afb8c15..1c8a93f6483ae 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/FieldFetcherTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/FieldFetcherTests.java
@@ -34,11 +34,11 @@
 
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.document.DocumentField;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.MapperService;
@@ -49,6 +49,7 @@
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
@@ -66,10 +67,7 @@ public void testLeafValues() throws IOException {
             .endObject()
             .endObject();
 
-        List<FieldAndFormat> fieldAndFormats = org.opensearch.common.collect.List.of(
-            new FieldAndFormat("field", null),
-            new FieldAndFormat("object.field", null)
-        );
+        List<FieldAndFormat> fieldAndFormats = List.of(new FieldAndFormat("field", null), new FieldAndFormat("object.field", null));
         Map<String, DocumentField> fields = fetchFields(mapperService, source, fieldAndFormats);
         assertThat(fields.size(), equalTo(2));
 
@@ -100,7 +98,7 @@ public void testObjectValues() throws IOException {
         DocumentField rangeField = fields.get("float_range");
         assertNotNull(rangeField);
         assertThat(rangeField.getValues().size(), equalTo(1));
-        assertThat(rangeField.getValue(), equalTo(org.opensearch.common.collect.Map.of("gte", 0.0f, "lte", 2.718f)));
+        assertThat(rangeField.getValue(), equalTo(Map.of("gte", 0.0f, "lte", 2.718f)));
     }
 
     public void testNonExistentField() throws IOException {
@@ -117,6 +115,11 @@ public void testMetadataFields() throws IOException {
 
         Map<String, DocumentField> fields = fetchFields(mapperService, source, "_routing");
         assertTrue(fields.isEmpty());
+
+        // The _type field was deprecated in 7.x and is not supported in 2.0. So the behavior
+        // should be the same as if the field didn't exist.
+        fields = fetchFields(mapperService, source, "_type");
+        assertTrue(fields.isEmpty());
     }
 
     public void testFetchAllFields() throws IOException {
@@ -250,7 +253,7 @@ public void testDateFormat() throws IOException {
         Map<String, DocumentField> fields = fetchFields(
             mapperService,
             source,
-            org.opensearch.common.collect.List.of(new FieldAndFormat("field", null), new FieldAndFormat("date_field", "yyyy/MM/dd"))
+            List.of(new FieldAndFormat("field", null), new FieldAndFormat("date_field", "yyyy/MM/dd"))
         );
         assertThat(fields.size(), equalTo(2));
 
@@ -435,7 +438,7 @@ public void testTextSubFields() throws IOException {
     private static Map<String, DocumentField> fetchFields(MapperService mapperService, XContentBuilder source, String fieldPattern)
         throws IOException {
 
-        List<FieldAndFormat> fields = org.opensearch.common.collect.List.of(new FieldAndFormat(fieldPattern, null));
+        List<FieldAndFormat> fields = List.of(new FieldAndFormat(fieldPattern, null));
         return fetchFields(mapperService, source, fields);
     }
 
@@ -446,7 +449,7 @@ private static Map<String, DocumentField> fetchFields(MapperService mapperServic
         sourceLookup.setSource(BytesReference.bytes(source));
 
         FieldFetcher fieldFetcher = FieldFetcher.create(createQueryShardContext(mapperService), null, fields);
-        return fieldFetcher.fetch(sourceLookup, org.opensearch.common.collect.Set.of());
+        return fieldFetcher.fetch(sourceLookup, Set.of());
     }
 
     public MapperService createMapperService() throws IOException {
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighter.java b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighter.java
index 710e89670de0a..649c9e26a70f3 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighter.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/CustomHighlighter.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.index.mapper.MappedFieldType;
 
 import java.util.ArrayList;
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilderTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilderTests.java
index 89834f80b59df..d07144c70da7d 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightBuilderTests.java
@@ -35,21 +35,21 @@
 import org.apache.lucene.search.Query;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ContentPath;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -66,8 +66,8 @@
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder.Field;
 import org.opensearch.search.fetch.subphase.highlight.HighlightBuilder.Order;
 import org.opensearch.search.fetch.subphase.highlight.SearchHighlightContext.FieldOptions;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
@@ -137,7 +137,7 @@ public void testEqualsAndHashcode() throws IOException {
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             HighlightBuilder highlightBuilder = randomHighlighterBuilder();
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 builder.prettyPrint();
             }
@@ -547,7 +547,7 @@ public void testOrderSerialization() throws Exception {
     }
 
     protected static XContentBuilder toXContent(HighlightBuilder highlight, XContentType contentType) throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(contentType);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(contentType);
         if (randomBoolean()) {
             builder.prettyPrint();
         }
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
index 6fb53c2ed1da0..38dbb0a4d1cad 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
@@ -32,16 +32,15 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -53,23 +52,36 @@ public class HighlightFieldTests extends OpenSearchTestCase {
 
     public static HighlightField createTestItem() {
         String name = frequently() ? randomAlphaOfLengthBetween(5, 20) : randomRealisticUnicodeOfCodepointLengthBetween(5, 20);
+        name = replaceUnicodeControlCharacters(name);
         Text[] fragments = null;
         if (frequently()) {
             int size = randomIntBetween(0, 5);
             fragments = new Text[size];
             for (int i = 0; i < size; i++) {
-                fragments[i] = new Text(
-                    frequently() ? randomAlphaOfLengthBetween(10, 30) : randomRealisticUnicodeOfCodepointLengthBetween(10, 30)
-                );
+                String fragmentText = frequently()
+                    ? randomAlphaOfLengthBetween(10, 30)
+                    : randomRealisticUnicodeOfCodepointLengthBetween(10, 30);
+                fragmentText = replaceUnicodeControlCharacters(fragmentText);
+                fragments[i] = new Text(fragmentText);
             }
         }
         return new HighlightField(name, fragments);
     }
 
+    public void testReplaceUnicodeControlCharacters() {
+        assertEquals("æÆ ¢¡Èýñ«Ò", replaceUnicodeControlCharacters("æÆ\u0000¢¡Èýñ«Ò"));
+        assertEquals("test_string_without_control_characters", replaceUnicodeControlCharacters("test_string_without_control_characters"));
+        assertEquals("æÆ@¢¡Èýñ«Ò", replaceUnicodeControlCharacters("æÆ\u0000¢¡Èýñ«Ò", "@"));
+        assertEquals(
+            "test_string_without_control_characters",
+            replaceUnicodeControlCharacters("test_string_without_control_characters", "@")
+        );
+    }
+
     public void testFromXContent() throws IOException {
         HighlightField highlightField = createTestItem();
         XContentType xcontentType = randomFrom(XContentType.values());
-        XContentBuilder builder = XContentFactory.contentBuilder(xcontentType);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(xcontentType);
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -96,7 +108,7 @@ public void testToXContent() throws IOException {
         builder.startObject();
         field.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        assertEquals("{\n" + "  \"foo\" : [\n" + "    \"bar\",\n" + "    \"baz\"\n" + "  ]\n" + "}", Strings.toString(builder));
+        assertEquals("{\n" + "  \"foo\" : [\n" + "    \"bar\",\n" + "    \"baz\"\n" + "  ]\n" + "}", builder.toString());
 
         field = new HighlightField("foo", null);
         builder = JsonXContent.contentBuilder();
@@ -104,7 +116,7 @@ public void testToXContent() throws IOException {
         builder.startObject();
         field.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        assertEquals("{\n" + "  \"foo\" : null\n" + "}", Strings.toString(builder));
+        assertEquals("{\n" + "  \"foo\" : null\n" + "}", builder.toString());
     }
 
     /**
diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighterTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighterTests.java
index 18288aeac13e1..1e5f7d3f9f489 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighterTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/PlainHighlighterTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.fetch.subphase.highlight;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.PhraseQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.highlight.QueryScorer;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.tests.util.LuceneTestCase;
 
 public class PlainHighlighterTests extends LuceneTestCase {
diff --git a/server/src/test/java/org/opensearch/search/geo/GeoPointShapeQueryTests.java b/server/src/test/java/org/opensearch/search/geo/GeoPointShapeQueryTests.java
index 3d4c82da0107e..b6b2a86ac7549 100644
--- a/server/src/test/java/org/opensearch/search/geo/GeoPointShapeQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/geo/GeoPointShapeQueryTests.java
@@ -42,8 +42,8 @@
 import org.opensearch.common.geo.builders.MultiLineStringBuilder;
 import org.opensearch.common.geo.builders.MultiPointBuilder;
 import org.opensearch.common.geo.builders.PointBuilder;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Line;
 import org.opensearch.geometry.LinearRing;
 import org.opensearch.geometry.MultiLine;
diff --git a/server/src/test/java/org/opensearch/search/geo/GeoQueryTests.java b/server/src/test/java/org/opensearch/search/geo/GeoQueryTests.java
index dfaadaa8875ca..1a1650c91776a 100644
--- a/server/src/test/java/org/opensearch/search/geo/GeoQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/geo/GeoQueryTests.java
@@ -42,9 +42,9 @@
 import org.opensearch.common.geo.builders.GeometryCollectionBuilder;
 import org.opensearch.common.geo.builders.MultiPolygonBuilder;
 import org.opensearch.common.geo.builders.PolygonBuilder;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.geometry.Geometry;
 import org.opensearch.geometry.Rectangle;
 import org.opensearch.index.query.GeoShapeQueryBuilder;
@@ -53,11 +53,12 @@
 import org.opensearch.search.SearchHits;
 import org.opensearch.test.OpenSearchSingleNodeTestCase;
 import org.opensearch.test.TestGeoShapeFieldMapperPlugin;
-import org.locationtech.jts.geom.Coordinate;
 
 import java.util.Collection;
 import java.util.Collections;
 
+import org.locationtech.jts.geom.Coordinate;
+
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
@@ -87,7 +88,7 @@ public void testNullShape() throws Exception {
 
         client().prepareIndex(defaultIndexName)
             .setId("aNullshape")
-            .setSource("{\"geo\": null}", XContentType.JSON)
+            .setSource("{\"geo\": null}", MediaTypeRegistry.JSON)
             .setRefreshPolicy(IMMEDIATE)
             .get();
         GetResponse result = client().prepareGet(defaultIndexName, "aNullshape").get();
diff --git a/server/src/test/java/org/opensearch/search/geo/GeoShapeQueryTests.java b/server/src/test/java/org/opensearch/search/geo/GeoShapeQueryTests.java
index d6c5e4f9a6083..1262ea4750a99 100644
--- a/server/src/test/java/org/opensearch/search/geo/GeoShapeQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/geo/GeoShapeQueryTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.search.geo;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.lucene.tests.geo.GeoTestUtil;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.common.CheckedSupplier;
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.ShapeRelation;
 import org.opensearch.common.geo.SpatialStrategy;
 import org.opensearch.common.geo.builders.CircleBuilder;
@@ -51,23 +51,23 @@
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.LegacyGeoShapeFieldMapper;
 import org.opensearch.index.mapper.MapperParsingException;
 import org.opensearch.index.query.ExistsQueryBuilder;
 import org.opensearch.index.query.GeoShapeQueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.test.geo.RandomShapeGenerator;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.spatial4j.shape.Rectangle;
 
 import java.io.IOException;
 import java.util.Locale;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.assumeTrue;
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.spatial4j.shape.Rectangle;
+
 import static org.opensearch.action.support.WriteRequest.RefreshPolicy.IMMEDIATE;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.opensearch.index.query.QueryBuilders.geoIntersectionQuery;
@@ -83,6 +83,7 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.not;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.assumeTrue;
 
 public class GeoShapeQueryTests extends GeoQueryTests {
     protected static final String[] PREFIX_TREES = new String[] {
@@ -156,7 +157,7 @@ public void testShapeFetchingPath() throws Exception {
             .setId("1")
             .setSource(
                 String.format(Locale.ROOT, "{ %s, \"1\" : { %s, \"2\" : { %s, \"3\" : { %s } }} }", location, location, location, location),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
             .setRefreshPolicy(IMMEDIATE)
             .get();
@@ -292,7 +293,7 @@ public void testEnvelopeSpanningDateline() throws Exception {
             + "],\r\n"
             + "\"type\": \"Point\"\r\n"
             + "}}";
-        client().index(new IndexRequest("test").id("1").source(doc1, XContentType.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
+        client().index(new IndexRequest("test").id("1").source(doc1, MediaTypeRegistry.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
 
         String doc2 = "{\"geo\": {\r\n"
             + "\"coordinates\": [\r\n"
@@ -301,7 +302,7 @@ public void testEnvelopeSpanningDateline() throws Exception {
             + "],\r\n"
             + "\"type\": \"Point\"\r\n"
             + "}}";
-        client().index(new IndexRequest("test").id("2").source(doc2, XContentType.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
+        client().index(new IndexRequest("test").id("2").source(doc2, MediaTypeRegistry.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
 
         String doc3 = "{\"geo\": {\r\n"
             + "\"coordinates\": [\r\n"
@@ -310,7 +311,7 @@ public void testEnvelopeSpanningDateline() throws Exception {
             + "],\r\n"
             + "\"type\": \"Point\"\r\n"
             + "}}";
-        client().index(new IndexRequest("test").id("3").source(doc3, XContentType.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
+        client().index(new IndexRequest("test").id("3").source(doc3, MediaTypeRegistry.JSON).setRefreshPolicy(IMMEDIATE)).actionGet();
 
         @SuppressWarnings("unchecked")
         CheckedSupplier<GeoShapeQueryBuilder, IOException> querySupplier = randomFrom(
@@ -438,7 +439,7 @@ public void testEdgeCases() throws Exception {
             .endObject()
             .endObject()
             .endObject();
-        String mapping = Strings.toString(xcb);
+        String mapping = xcb.toString();
         client().admin().indices().prepareCreate("test").setMapping(mapping).get();
         ensureGreen();
 
@@ -524,9 +525,9 @@ public void testReusableBuilder() throws IOException {
     }
 
     private void assertUnmodified(ShapeBuilder builder) throws IOException {
-        String before = Strings.toString(jsonBuilder().startObject().field("area", builder).endObject());
+        String before = jsonBuilder().startObject().field("area", builder).endObject().toString();
         builder.buildS4J();
-        String after = Strings.toString(jsonBuilder().startObject().field("area", builder).endObject());
+        String after = jsonBuilder().startObject().field("area", builder).endObject().toString();
         assertThat(before, equalTo(after));
     }
 
@@ -614,20 +615,19 @@ public void testExistsQuery() throws Exception {
     }
 
     public void testPointsOnly() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("location")
-                .field("type", "geo_shape")
-                .field("tree", randomBoolean() ? "quadtree" : "geohash")
-                .field("tree_levels", "6")
-                .field("distance_error_pct", "0.01")
-                .field("points_only", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("location")
+            .field("type", "geo_shape")
+            .field("tree", randomBoolean() ? "quadtree" : "geohash")
+            .field("tree_levels", "6")
+            .field("distance_error_pct", "0.01")
+            .field("points_only", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         client().admin().indices().prepareCreate("geo_points_only").setMapping(mapping).get();
         ensureGreen();
@@ -652,20 +652,19 @@ public void testPointsOnly() throws Exception {
     }
 
     public void testPointsOnlyExplicit() throws Exception {
-        String mapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("properties")
-                .startObject("geo")
-                .field("type", "geo_shape")
-                .field("tree", randomBoolean() ? "quadtree" : "geohash")
-                .field("tree_levels", "6")
-                .field("distance_error_pct", "0.01")
-                .field("points_only", true)
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("properties")
+            .startObject("geo")
+            .field("type", "geo_shape")
+            .field("tree", randomBoolean() ? "quadtree" : "geohash")
+            .field("tree_levels", "6")
+            .field("distance_error_pct", "0.01")
+            .field("points_only", true)
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         client().admin().indices().prepareCreate("geo_points_only").setMapping(mapping).get();
         ensureGreen();
@@ -693,7 +692,7 @@ public void testPointsOnlyExplicit() throws Exception {
     }
 
     public void testIndexedShapeReference() throws Exception {
-        String mapping = Strings.toString(createDefaultMapping());
+        String mapping = createDefaultMapping().toString();
         client().admin().indices().prepareCreate("test").setMapping(mapping).get();
         createIndex("shapes");
         ensureGreen();
@@ -888,7 +887,7 @@ public void testShapeFilterWithDefinedGeoCollection() throws Exception {
     }
 
     public void testDistanceQuery() throws Exception {
-        String mapping = Strings.toString(createRandomMapping());
+        String mapping = createRandomMapping().toString();
         client().admin().indices().prepareCreate("test_distance").setMapping(mapping).get();
         ensureGreen();
 
@@ -930,7 +929,7 @@ public void testDistanceQuery() throws Exception {
     }
 
     public void testIndexRectangleSpanningDateLine() throws Exception {
-        String mapping = Strings.toString(createRandomMapping());
+        String mapping = createRandomMapping().toString();
 
         client().admin().indices().prepareCreate("test").setMapping(mapping).get();
         ensureGreen();
diff --git a/server/src/test/java/org/opensearch/search/internal/AliasFilterTests.java b/server/src/test/java/org/opensearch/search/internal/AliasFilterTests.java
index 52b7d383fb9b8..e968e0740b150 100644
--- a/server/src/test/java/org/opensearch/search/internal/AliasFilterTests.java
+++ b/server/src/test/java/org/opensearch/search/internal/AliasFilterTests.java
@@ -36,8 +36,8 @@
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 
diff --git a/server/src/test/java/org/opensearch/search/internal/ContextIndexSearcherTests.java b/server/src/test/java/org/opensearch/search/internal/ContextIndexSearcherTests.java
index de0a31b9dc04b..5b6e668175748 100644
--- a/server/src/test/java/org/opensearch/search/internal/ContextIndexSearcherTests.java
+++ b/server/src/test/java/org/opensearch/search/internal/ContextIndexSearcherTests.java
@@ -40,7 +40,6 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReader;
@@ -77,26 +76,32 @@
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.lucene.index.SequentialStoredFieldsLeafReader;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.search.SearchBootstrapSettings;
 import org.opensearch.search.aggregations.LeafBucketCollector;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.Collections;
 import java.util.IdentityHashMap;
+import java.util.List;
 import java.util.Set;
 
 import static org.opensearch.search.internal.ContextIndexSearcher.intersectScorerAndBitSet;
 import static org.opensearch.search.internal.ExitableDirectoryReader.ExitableLeafReader;
 import static org.opensearch.search.internal.ExitableDirectoryReader.ExitablePointValues;
 import static org.opensearch.search.internal.ExitableDirectoryReader.ExitableTerms;
+import static org.opensearch.search.internal.IndexReaderUtils.getLeaves;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class ContextIndexSearcherTests extends OpenSearchTestCase {
     public void testIntersectScorerAndRoleBits() throws Exception {
@@ -253,12 +258,18 @@ public void onRemoval(ShardId shardId, Accountable accountable) {
 
         DocumentSubsetDirectoryReader filteredReader = new DocumentSubsetDirectoryReader(reader, cache, roleQuery);
 
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
         ContextIndexSearcher searcher = new ContextIndexSearcher(
             filteredReader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            null,
+            searchContext
         );
 
         for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
@@ -295,6 +306,59 @@ public void onRemoval(ShardId shardId, Accountable accountable) {
         IOUtils.close(reader, w, dir);
     }
 
+    public void testSlicesInternal() throws Exception {
+        final List<LeafReaderContext> leaves = getLeaves(10);
+
+        final Directory directory = newDirectory();
+        IndexWriter iw = new IndexWriter(directory, new IndexWriterConfig(new StandardAnalyzer()).setMergePolicy(NoMergePolicy.INSTANCE));
+        Document document = new Document();
+        document.add(new StringField("field1", "value1", Field.Store.NO));
+        document.add(new StringField("field2", "value1", Field.Store.NO));
+        iw.addDocument(document);
+        iw.commit();
+        DirectoryReader directoryReader = DirectoryReader.open(directory);
+
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
+        ContextIndexSearcher searcher = new ContextIndexSearcher(
+            directoryReader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            null,
+            searchContext
+        );
+        // Case 1: Verify the slice count when lucene default slice computation is used
+        IndexSearcher.LeafSlice[] slices = searcher.slicesInternal(
+            leaves,
+            SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_DEFAULT_VALUE
+        );
+        int expectedSliceCount = 2;
+        // 2 slices will be created since max segment per slice of 5 will be reached
+        assertEquals(expectedSliceCount, slices.length);
+        for (int i = 0; i < expectedSliceCount; ++i) {
+            assertEquals(5, slices[i].leaves.length);
+        }
+
+        // Case 2: Verify the slice count when custom max slice computation is used
+        expectedSliceCount = 4;
+        slices = searcher.slicesInternal(leaves, expectedSliceCount);
+
+        // 4 slices will be created with 3 leaves in first 2 slices and 2 leaves in other slices
+        assertEquals(expectedSliceCount, slices.length);
+        for (int i = 0; i < expectedSliceCount; ++i) {
+            if (i < 2) {
+                assertEquals(3, slices[i].leaves.length);
+            } else {
+                assertEquals(2, slices[i].leaves.length);
+            }
+        }
+        IOUtils.close(directoryReader, iw, directory);
+    }
+
     private SparseFixedBitSet query(LeafReaderContext leaf, String field, String value) throws IOException {
         SparseFixedBitSet sparseFixedBitSet = new SparseFixedBitSet(leaf.reader().maxDoc());
         TermsEnum tenum = leaf.reader().terms(field).iterator();
@@ -457,12 +521,12 @@ public String toString(String field) {
         }
 
         @Override
-        public Query rewrite(IndexReader reader) throws IOException {
-            Query queryRewritten = query.rewrite(reader);
+        public Query rewrite(IndexSearcher searcher) throws IOException {
+            Query queryRewritten = query.rewrite(searcher);
             if (query != queryRewritten) {
                 return new CreateScorerOnceQuery(queryRewritten);
             }
-            return super.rewrite(reader);
+            return super.rewrite(searcher);
         }
 
         @Override
diff --git a/server/src/test/java/org/opensearch/search/internal/IndexReaderUtils.java b/server/src/test/java/org/opensearch/search/internal/IndexReaderUtils.java
new file mode 100644
index 0000000000000..a87bb8a52cdd0
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/internal/IndexReaderUtils.java
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.internal;
+
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.store.Directory;
+
+import java.util.List;
+
+import static org.apache.lucene.tests.util.LuceneTestCase.newDirectory;
+
+public class IndexReaderUtils {
+
+    /**
+     * Utility to create leafCount number of {@link LeafReaderContext}
+     * @param leafCount count of leaves to create
+     * @return created leaves
+     */
+    public static List<LeafReaderContext> getLeaves(int leafCount) throws Exception {
+        final Directory directory = newDirectory();
+        IndexWriter iw = new IndexWriter(directory, new IndexWriterConfig(new StandardAnalyzer()).setMergePolicy(NoMergePolicy.INSTANCE));
+        for (int i = 0; i < leafCount; ++i) {
+            Document document = new Document();
+            final String fieldValue = "value" + i;
+            document.add(new StringField("field1", fieldValue, Field.Store.NO));
+            document.add(new StringField("field2", fieldValue, Field.Store.NO));
+            iw.addDocument(document);
+            iw.commit();
+        }
+        iw.close();
+        DirectoryReader directoryReader = DirectoryReader.open(directory);
+        List<LeafReaderContext> leaves = directoryReader.leaves();
+        directoryReader.close();
+        directory.close();
+        return leaves;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/internal/MaxTargetSliceSupplierTests.java b/server/src/test/java/org/opensearch/search/internal/MaxTargetSliceSupplierTests.java
new file mode 100644
index 0000000000000..2684cf901f080
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/internal/MaxTargetSliceSupplierTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.internal;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.IndexSearcher;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.opensearch.search.internal.IndexReaderUtils.getLeaves;
+
+public class MaxTargetSliceSupplierTests extends OpenSearchTestCase {
+
+    public void testSliceCountGreaterThanLeafCount() throws Exception {
+        int expectedSliceCount = 2;
+        IndexSearcher.LeafSlice[] slices = MaxTargetSliceSupplier.getSlices(getLeaves(expectedSliceCount), 5);
+        // verify slice count is same as leaf count
+        assertEquals(expectedSliceCount, slices.length);
+        for (int i = 0; i < expectedSliceCount; ++i) {
+            assertEquals(1, slices[i].leaves.length);
+        }
+    }
+
+    public void testNegativeSliceCount() {
+        assertThrows(IllegalArgumentException.class, () -> MaxTargetSliceSupplier.getSlices(new ArrayList<>(), randomIntBetween(-3, 0)));
+    }
+
+    public void testSingleSliceWithMultipleLeaves() throws Exception {
+        int leafCount = randomIntBetween(1, 10);
+        IndexSearcher.LeafSlice[] slices = MaxTargetSliceSupplier.getSlices(getLeaves(leafCount), 1);
+        assertEquals(1, slices.length);
+        assertEquals(leafCount, slices[0].leaves.length);
+    }
+
+    public void testSliceCountLessThanLeafCount() throws Exception {
+        int leafCount = 12;
+        List<LeafReaderContext> leaves = getLeaves(leafCount);
+
+        // Case 1: test with equal number of leaves per slice
+        int expectedSliceCount = 3;
+        IndexSearcher.LeafSlice[] slices = MaxTargetSliceSupplier.getSlices(leaves, expectedSliceCount);
+        int expectedLeavesPerSlice = leafCount / expectedSliceCount;
+
+        assertEquals(expectedSliceCount, slices.length);
+        for (int i = 0; i < expectedSliceCount; ++i) {
+            assertEquals(expectedLeavesPerSlice, slices[i].leaves.length);
+        }
+
+        // Case 2: test with first 2 slice more leaves than others
+        expectedSliceCount = 5;
+        slices = MaxTargetSliceSupplier.getSlices(leaves, expectedSliceCount);
+        int expectedLeavesInFirst2Slice = 3;
+        int expectedLeavesInOtherSlice = 2;
+
+        assertEquals(expectedSliceCount, slices.length);
+        for (int i = 0; i < expectedSliceCount; ++i) {
+            if (i < 2) {
+                assertEquals(expectedLeavesInFirst2Slice, slices[i].leaves.length);
+            } else {
+                assertEquals(expectedLeavesInOtherSlice, slices[i].leaves.length);
+            }
+        }
+    }
+
+    public void testEmptyLeaves() {
+        IndexSearcher.LeafSlice[] slices = MaxTargetSliceSupplier.getSlices(new ArrayList<>(), 2);
+        assertEquals(0, slices.length);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/internal/ShardSearchRequestTests.java b/server/src/test/java/org/opensearch/search/internal/ShardSearchRequestTests.java
index eed3f99150b16..c65262253d1fc 100644
--- a/server/src/test/java/org/opensearch/search/internal/ShardSearchRequestTests.java
+++ b/server/src/test/java/org/opensearch/search/internal/ShardSearchRequestTests.java
@@ -38,20 +38,21 @@
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.RandomQueryBuilder;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.InvalidAliasNameException;
 import org.opensearch.search.AbstractSearchTestCase;
 import org.opensearch.search.SearchSortValuesAndFormatsTests;
@@ -205,7 +206,7 @@ public static CompressedXContent filter(QueryBuilder filterBuilder) throws IOExc
         XContentBuilder builder = XContentFactory.jsonBuilder();
         filterBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.close();
-        return new CompressedXContent(Strings.toString(builder));
+        return new CompressedXContent(builder.toString());
     }
 
     private IndexMetadata remove(IndexMetadata indexMetadata, String alias) {
@@ -220,7 +221,7 @@ public QueryBuilder aliasFilter(IndexMetadata indexMetadata, String... aliasName
         return ShardSearchRequest.parseAliasFilter(bytes -> {
             try (
                 InputStream inputStream = bytes.streamInput();
-                XContentParser parser = XContentFactory.xContentType(inputStream)
+                XContentParser parser = MediaTypeRegistry.xContentType(inputStream)
                     .xContent()
                     .createParser(xContentRegistry(), DeprecationHandler.THROW_UNSUPPORTED_OPERATION, inputStream)
             ) {
diff --git a/server/src/test/java/org/opensearch/search/lookup/LeafDocLookupTests.java b/server/src/test/java/org/opensearch/search/lookup/LeafDocLookupTests.java
index b047f16583ee5..0f3a9e49f263e 100644
--- a/server/src/test/java/org/opensearch/search/lookup/LeafDocLookupTests.java
+++ b/server/src/test/java/org/opensearch/search/lookup/LeafDocLookupTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.search.lookup;
 
-import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.IndexFieldData;
+import org.opensearch.index.fielddata.LeafFieldData;
 import org.opensearch.index.fielddata.ScriptDocValues;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
diff --git a/server/src/test/java/org/opensearch/search/lookup/LeafFieldsLookupTests.java b/server/src/test/java/org/opensearch/search/lookup/LeafFieldsLookupTests.java
index 7deb6845af607..85aacfbd63ee2 100644
--- a/server/src/test/java/org/opensearch/search/lookup/LeafFieldsLookupTests.java
+++ b/server/src/test/java/org/opensearch/search/lookup/LeafFieldsLookupTests.java
@@ -36,17 +36,19 @@
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.StoredFieldVisitor;
+import org.apache.lucene.index.StoredFields;
+import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.index.VectorSimilarityFunction;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
+import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -81,17 +83,18 @@ public void setUp() throws Exception {
             0,
             0,
             0,
+            VectorEncoding.FLOAT32,
             VectorSimilarityFunction.EUCLIDEAN,
             false
         );
 
         LeafReader leafReader = mock(LeafReader.class);
-        doAnswer(invocation -> {
-            Object[] args = invocation.getArguments();
-            StoredFieldVisitor visitor = (StoredFieldVisitor) args[1];
-            visitor.doubleField(mockFieldInfo, 2.718);
-            return null;
-        }).when(leafReader).document(anyInt(), any(StoredFieldVisitor.class));
+        doAnswer(invocation -> new StoredFields() {
+            @Override
+            public void document(int docID, StoredFieldVisitor visitor) throws IOException {
+                visitor.doubleField(mockFieldInfo, 2.718);
+            }
+        }).when(leafReader).storedFields();
 
         fieldsLookup = new LeafFieldsLookup(mapperService, leafReader);
     }
diff --git a/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineInfoTests.java b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineInfoTests.java
new file mode 100644
index 0000000000000..c19c1ebcb5c26
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineInfoTests.java
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.Version;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+public class SearchPipelineInfoTests extends OpenSearchTestCase {
+    public void testSerializationRoundtrip() throws IOException {
+        SearchPipelineInfo searchPipelineInfo = new SearchPipelineInfo(
+            Map.of(
+                "a",
+                List.of(new ProcessorInfo("a1"), new ProcessorInfo("a2"), new ProcessorInfo("a3")),
+                "b",
+                List.of(new ProcessorInfo("b1"), new ProcessorInfo("b2")),
+                "c",
+                List.of(new ProcessorInfo("c1"))
+            )
+        );
+        SearchPipelineInfo deserialized;
+        try (BytesStreamOutput bytesStreamOutput = new BytesStreamOutput()) {
+            searchPipelineInfo.writeTo(bytesStreamOutput);
+            try (StreamInput bytesStreamInput = bytesStreamOutput.bytes().streamInput()) {
+                deserialized = new SearchPipelineInfo(bytesStreamInput);
+            }
+        }
+        assertTrue(deserialized.containsProcessor("a", "a1"));
+        assertTrue(deserialized.containsProcessor("a", "a2"));
+        assertTrue(deserialized.containsProcessor("a", "a3"));
+        assertTrue(deserialized.containsProcessor("b", "b1"));
+        assertTrue(deserialized.containsProcessor("b", "b2"));
+        assertTrue(deserialized.containsProcessor("c", "c1"));
+    }
+
+    /**
+     * When serializing / deserializing to / from old versions, processor type info is lost.
+     *
+     * Also, we only supported request/response processors.
+     */
+    public void testSerializationRoundtripBackcompat() throws IOException {
+        SearchPipelineInfo searchPipelineInfo = new SearchPipelineInfo(
+            Map.of(
+                Pipeline.REQUEST_PROCESSORS_KEY,
+                List.of(new ProcessorInfo("a1"), new ProcessorInfo("a2"), new ProcessorInfo("a3")),
+                Pipeline.RESPONSE_PROCESSORS_KEY,
+                List.of(new ProcessorInfo("b1"), new ProcessorInfo("b2"))
+            )
+        );
+        SearchPipelineInfo deserialized;
+        try (BytesStreamOutput bytesStreamOutput = new BytesStreamOutput()) {
+            bytesStreamOutput.setVersion(Version.V_2_7_0);
+            searchPipelineInfo.writeTo(bytesStreamOutput);
+            try (StreamInput bytesStreamInput = bytesStreamOutput.bytes().streamInput()) {
+                bytesStreamInput.setVersion(Version.V_2_7_0);
+                deserialized = new SearchPipelineInfo(bytesStreamInput);
+            }
+        }
+        for (String proc : List.of("a1", "a2", "a3", "b1", "b2")) {
+            assertTrue(deserialized.containsProcessor(Pipeline.REQUEST_PROCESSORS_KEY, proc));
+            assertTrue(deserialized.containsProcessor(Pipeline.RESPONSE_PROCESSORS_KEY, proc));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineServiceTests.java b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineServiceTests.java
new file mode 100644
index 0000000000000..d44bd3831281f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineServiceTests.java
@@ -0,0 +1,1339 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TotalHits;
+import org.opensearch.OpenSearchParseException;
+import org.opensearch.ResourceNotFoundException;
+import org.opensearch.Version;
+import org.opensearch.action.search.DeleteSearchPipelineRequest;
+import org.opensearch.action.search.MockSearchPhaseContext;
+import org.opensearch.action.search.PutSearchPipelineRequest;
+import org.opensearch.action.search.QueryPhaseResultConsumer;
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseController;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchPhaseResults;
+import org.opensearch.action.search.SearchProgressListener;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchResponseSections;
+import org.opensearch.client.Client;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.query.TermQueryBuilder;
+import org.opensearch.plugins.SearchPipelinePlugin;
+import org.opensearch.search.SearchHit;
+import org.opensearch.search.SearchHits;
+import org.opensearch.search.SearchModule;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.Before;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.function.Consumer;
+
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SearchPipelineServiceTests extends OpenSearchTestCase {
+
+    private static final SearchPipelinePlugin DUMMY_PLUGIN = new SearchPipelinePlugin() {
+        @Override
+        public Map<String, Processor.Factory<SearchRequestProcessor>> getRequestProcessors(Parameters parameters) {
+            return Map.of("foo", (factories, tag, description, ignoreFailure, config, ctx) -> null);
+        }
+
+        public Map<String, Processor.Factory<SearchResponseProcessor>> getResponseProcessors(Parameters parameters) {
+            return Map.of("bar", (factories, tag, description, ignoreFailure, config, ctx) -> null);
+        }
+
+        @Override
+        public Map<String, Processor.Factory<SearchPhaseResultsProcessor>> getSearchPhaseResultsProcessors(Parameters parameters) {
+            return Map.of("zoe", (factories, tag, description, ignoreFailure, config, ctx) -> null);
+        }
+    };
+
+    private ThreadPool threadPool;
+
+    @Before
+    public void setup() {
+        threadPool = mock(ThreadPool.class);
+        ExecutorService executorService = OpenSearchExecutors.newDirectExecutorService();
+        when(threadPool.generic()).thenReturn(executorService);
+        when(threadPool.executor(anyString())).thenReturn(executorService);
+    }
+
+    public void testSearchPipelinePlugin() {
+        Client client = mock(Client.class);
+        SearchPipelineService searchPipelineService = new SearchPipelineService(
+            mock(ClusterService.class),
+            threadPool,
+            null,
+            null,
+            null,
+            this.xContentRegistry(),
+            this.writableRegistry(),
+            List.of(DUMMY_PLUGIN),
+            client
+        );
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorFactories = searchPipelineService
+            .getRequestProcessorFactories();
+        assertEquals(1, requestProcessorFactories.size());
+        assertTrue(requestProcessorFactories.containsKey("foo"));
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessorFactories = searchPipelineService
+            .getResponseProcessorFactories();
+        assertEquals(1, responseProcessorFactories.size());
+        assertTrue(responseProcessorFactories.containsKey("bar"));
+    }
+
+    public void testSearchPipelinePluginDuplicate() {
+        Client client = mock(Client.class);
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> new SearchPipelineService(
+                mock(ClusterService.class),
+                threadPool,
+                null,
+                null,
+                null,
+                this.xContentRegistry(),
+                this.writableRegistry(),
+                List.of(DUMMY_PLUGIN, DUMMY_PLUGIN),
+                client
+            )
+        );
+        assertTrue(e.getMessage(), e.getMessage().contains(" already registered"));
+    }
+
+    public void testResolveSearchPipelineDoesNotExist() {
+        Client client = mock(Client.class);
+        SearchPipelineService searchPipelineService = new SearchPipelineService(
+            mock(ClusterService.class),
+            threadPool,
+            null,
+            null,
+            null,
+            this.xContentRegistry(),
+            this.writableRegistry(),
+            List.of(DUMMY_PLUGIN),
+            client
+        );
+        final SearchRequest searchRequest = new SearchRequest("_index").pipeline("bar");
+        IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> searchPipelineService.resolvePipeline(searchRequest)
+        );
+        assertTrue(e.getMessage(), e.getMessage().contains(" not defined"));
+    }
+
+    public void testResolveIndexDefaultPipeline() throws Exception {
+        SearchPipelineService service = createWithProcessors();
+
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration(
+                    "p1",
+                    new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ] }"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+        Settings defaultPipelineSetting = Settings.builder()
+            .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+            .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0)
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), Version.CURRENT)
+            .put(IndexSettings.DEFAULT_SEARCH_PIPELINE.getKey(), "p1")
+            .build();
+        IndexMetadata indexMetadata = new IndexMetadata.Builder("my_index").settings(defaultPipelineSetting).build();
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().put(indexMetadata, false).putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+
+        ClusterChangedEvent cce = new ClusterChangedEvent("", clusterState, previousState);
+        service.applyClusterState(cce);
+
+        SearchRequest searchRequest = new SearchRequest("my_index").source(SearchSourceBuilder.searchSource().size(5));
+        PipelinedRequest pipelinedRequest = service.resolvePipeline(searchRequest);
+        assertEquals("p1", pipelinedRequest.getPipeline().getId());
+        assertEquals(10, pipelinedRequest.source().size());
+
+        // Bypass the default pipeline
+        searchRequest.pipeline("_none");
+        pipelinedRequest = service.resolvePipeline(searchRequest);
+        assertEquals("_none", pipelinedRequest.getPipeline().getId());
+        assertEquals(5, pipelinedRequest.source().size());
+    }
+
+    private static class FakeRequestProcessor extends AbstractProcessor implements SearchRequestProcessor {
+        private final Consumer<SearchRequest> executor;
+
+        private final String type;
+
+        public FakeRequestProcessor(String type, String tag, String description, boolean ignoreFailure, Consumer<SearchRequest> executor) {
+            super(tag, description, ignoreFailure);
+            this.executor = executor;
+            this.type = type;
+        }
+
+        @Override
+        public SearchRequest processRequest(SearchRequest request) throws Exception {
+            executor.accept(request);
+            return request;
+        }
+
+        /*
+         * Gets the type of processor
+         */
+        @Override
+        public String getType() {
+            return this.type;
+        }
+    }
+
+    private static class FakeResponseProcessor extends AbstractProcessor implements SearchResponseProcessor {
+        private final Consumer<SearchResponse> executor;
+        private String type;
+
+        public FakeResponseProcessor(
+            String type,
+            String tag,
+            String description,
+            boolean ignoreFailure,
+            Consumer<SearchResponse> executor
+        ) {
+            super(tag, description, ignoreFailure);
+            this.executor = executor;
+            this.type = type;
+        }
+
+        @Override
+        public SearchResponse processResponse(SearchRequest request, SearchResponse response) throws Exception {
+            executor.accept(response);
+            return response;
+        }
+
+        /**
+         * Gets the type of processor
+         */
+        @Override
+        public String getType() {
+            return this.type;
+        }
+    }
+
+    private static class FakeSearchPhaseResultsProcessor extends AbstractProcessor implements SearchPhaseResultsProcessor {
+        private Consumer<SearchPhaseResult> querySearchResultConsumer;
+
+        private String type;
+
+        public FakeSearchPhaseResultsProcessor(
+            String type,
+            String tag,
+            String description,
+            boolean ignoreFailure,
+            Consumer<SearchPhaseResult> querySearchResultConsumer
+        ) {
+            super(tag, description, ignoreFailure);
+            this.querySearchResultConsumer = querySearchResultConsumer;
+            this.type = type;
+        }
+
+        @Override
+        public <Result extends SearchPhaseResult> void process(
+            SearchPhaseResults<Result> searchPhaseResult,
+            SearchPhaseContext searchPhaseContext
+        ) {
+            List<Result> resultAtomicArray = searchPhaseResult.getAtomicArray().asList();
+            // updating the maxScore
+            resultAtomicArray.forEach(querySearchResultConsumer);
+        }
+
+        @Override
+        public SearchPhaseName getBeforePhase() {
+            return SearchPhaseName.QUERY;
+        }
+
+        @Override
+        public SearchPhaseName getAfterPhase() {
+            return SearchPhaseName.FETCH;
+        }
+
+        /**
+         * Gets the type of processor
+         */
+        @Override
+        public String getType() {
+            return this.type;
+        }
+    }
+
+    private SearchPipelineService createWithProcessors() {
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessors = new HashMap<>();
+        requestProcessors.put("scale_request_size", (processorFactories, tag, description, ignoreFailure, config, ctx) -> {
+            float scale = ((Number) config.remove("scale")).floatValue();
+            return new FakeRequestProcessor(
+                "scale_request_size",
+                tag,
+                description,
+                ignoreFailure,
+                req -> req.source().size((int) (req.source().size() * scale))
+            );
+        });
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessors = new HashMap<>();
+        responseProcessors.put("fixed_score", (processorFactories, tag, description, ignoreFailure, config, ctx) -> {
+            float score = ((Number) config.remove("score")).floatValue();
+            return new FakeResponseProcessor(
+                "fixed_score",
+                tag,
+                description,
+                ignoreFailure,
+                rsp -> rsp.getHits().forEach(h -> h.score(score))
+            );
+        });
+
+        Map<String, Processor.Factory<SearchPhaseResultsProcessor>> searchPhaseProcessors = new HashMap<>();
+        searchPhaseProcessors.put("max_score", (processorFactories, tag, description, ignoreFailure, config, context) -> {
+            final float finalScore = config.containsKey("score") ? ((Number) config.remove("score")).floatValue() : 100f;
+            final Consumer<SearchPhaseResult> querySearchResultConsumer = (result) -> result.queryResult().topDocs().maxScore = finalScore;
+            return new FakeSearchPhaseResultsProcessor("max_score", tag, description, ignoreFailure, querySearchResultConsumer);
+        });
+
+        return createWithProcessors(requestProcessors, responseProcessors, searchPhaseProcessors);
+    }
+
+    @Override
+    protected NamedWriteableRegistry writableRegistry() {
+        SearchModule searchModule = new SearchModule(Settings.EMPTY, Collections.emptyList());
+        return new NamedWriteableRegistry(searchModule.getNamedWriteables());
+    }
+
+    private SearchPipelineService createWithProcessors(
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessors,
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessors,
+        Map<String, Processor.Factory<SearchPhaseResultsProcessor>> phaseProcessors
+    ) {
+        Client client = mock(Client.class);
+        ThreadPool threadPool = mock(ThreadPool.class);
+        ExecutorService executorService = OpenSearchExecutors.newDirectExecutorService();
+        when(threadPool.generic()).thenReturn(executorService);
+        when(threadPool.executor(anyString())).thenReturn(executorService);
+        return new SearchPipelineService(
+            mock(ClusterService.class),
+            threadPool,
+            null,
+            null,
+            null,
+            null,
+            this.writableRegistry(),
+            Collections.singletonList(new SearchPipelinePlugin() {
+                @Override
+                public Map<String, Processor.Factory<SearchRequestProcessor>> getRequestProcessors(Parameters parameters) {
+                    return requestProcessors;
+                }
+
+                @Override
+                public Map<String, Processor.Factory<SearchResponseProcessor>> getResponseProcessors(Parameters parameters) {
+                    return responseProcessors;
+                }
+
+                @Override
+                public Map<String, Processor.Factory<SearchPhaseResultsProcessor>> getSearchPhaseResultsProcessors(Parameters parameters) {
+                    return phaseProcessors;
+                }
+
+            }),
+            client
+        );
+    }
+
+    public void testUpdatePipelines() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousClusterState = clusterState;
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
+        assertEquals(0, searchPipelineService.getPipelines().size());
+
+        PipelineConfiguration pipeline = new PipelineConfiguration(
+            "_id",
+            new BytesArray(
+                "{ "
+                    + "\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ], "
+                    + "\"response_processors\" : [ { \"fixed_score\" : { \"score\" : 1.0 } } ],"
+                    + "\"phase_results_processors\" : [ { \"max_score\" : { \"score\": 100 } } ]"
+                    + "}"
+            ),
+            MediaTypeRegistry.JSON
+        );
+        SearchPipelineMetadata pipelineMetadata = new SearchPipelineMetadata(Map.of("_id", pipeline));
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, pipelineMetadata).build())
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
+        assertEquals(1, searchPipelineService.getPipelines().size());
+        assertEquals("_id", searchPipelineService.getPipelines().get("_id").pipeline.getId());
+        assertNull(searchPipelineService.getPipelines().get("_id").pipeline.getDescription());
+        assertEquals(1, searchPipelineService.getPipelines().get("_id").pipeline.getSearchRequestProcessors().size());
+        assertEquals(
+            "scale_request_size",
+            searchPipelineService.getPipelines().get("_id").pipeline.getSearchRequestProcessors().get(0).getType()
+        );
+        assertEquals(1, searchPipelineService.getPipelines().get("_id").pipeline.getSearchPhaseResultsProcessors().size());
+        assertEquals(
+            "max_score",
+            searchPipelineService.getPipelines().get("_id").pipeline.getSearchPhaseResultsProcessors().get(0).getType()
+        );
+        assertEquals(1, searchPipelineService.getPipelines().get("_id").pipeline.getSearchResponseProcessors().size());
+        assertEquals(
+            "fixed_score",
+            searchPipelineService.getPipelines().get("_id").pipeline.getSearchResponseProcessors().get(0).getType()
+        );
+    }
+
+    public void testPutPipeline() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        String id = "_id";
+        SearchPipelineService.PipelineHolder pipeline = searchPipelineService.getPipelines().get(id);
+        assertNull(pipeline);
+
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+
+        PutSearchPipelineRequest putRequest = new PutSearchPipelineRequest(id, new BytesArray("{}"), MediaTypeRegistry.JSON);
+        ClusterState previousClusterState = clusterState;
+        clusterState = SearchPipelineService.innerPut(putRequest, clusterState);
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
+        pipeline = searchPipelineService.getPipelines().get(id);
+        assertNotNull(pipeline);
+        assertEquals(id, pipeline.pipeline.getId());
+        assertNull(pipeline.pipeline.getDescription());
+        assertEquals(0, pipeline.pipeline.getSearchRequestProcessors().size());
+        assertEquals(0, pipeline.pipeline.getSearchResponseProcessors().size());
+
+        // Overwrite pipeline
+        putRequest = new PutSearchPipelineRequest(id, new BytesArray("{ \"description\": \"empty pipeline\"}"), MediaTypeRegistry.JSON);
+        previousClusterState = clusterState;
+        clusterState = SearchPipelineService.innerPut(putRequest, clusterState);
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
+        pipeline = searchPipelineService.getPipelines().get(id);
+        assertNotNull(pipeline);
+        assertEquals(id, pipeline.pipeline.getId());
+        assertEquals("empty pipeline", pipeline.pipeline.getDescription());
+        assertEquals(0, pipeline.pipeline.getSearchRequestProcessors().size());
+        assertEquals(0, pipeline.pipeline.getSearchResponseProcessors().size());
+        assertEquals(0, pipeline.pipeline.getSearchPhaseResultsProcessors().size());
+    }
+
+    public void testPutInvalidPipeline() throws IllegalAccessException {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        String id = "_id";
+
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+
+        PutSearchPipelineRequest putRequest = new PutSearchPipelineRequest(
+            id,
+            new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : \"foo\" } } ] }"),
+            MediaTypeRegistry.JSON
+        );
+        clusterState = SearchPipelineService.innerPut(putRequest, clusterState);
+        try (MockLogAppender mockAppender = MockLogAppender.createForLoggers(LogManager.getLogger(SearchPipelineService.class))) {
+            mockAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "test1",
+                    SearchPipelineService.class.getCanonicalName(),
+                    Level.WARN,
+                    "failed to update search pipelines"
+                )
+            );
+            searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+            mockAppender.assertAllExpectationsMatched();
+        }
+        assertEquals(0, searchPipelineService.getPipelines().size());
+    }
+
+    public void testDeletePipeline() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        PipelineConfiguration config = new PipelineConfiguration(
+            "_id",
+            new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ] }"),
+            MediaTypeRegistry.JSON
+        );
+        SearchPipelineMetadata searchPipelineMetadata = new SearchPipelineMetadata(Map.of("_id", config));
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, searchPipelineMetadata).build())
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        assertEquals(1, searchPipelineService.getPipelines().size());
+
+        // Delete pipeline:
+        DeleteSearchPipelineRequest deleteRequest = new DeleteSearchPipelineRequest("_id");
+        previousState = clusterState;
+        clusterState = SearchPipelineService.innerDelete(deleteRequest, clusterState);
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        assertEquals(0, searchPipelineService.getPipelines().size());
+
+        final ClusterState finalClusterState = clusterState;
+        // Delete missing pipeline
+        ResourceNotFoundException e = expectThrows(
+            ResourceNotFoundException.class,
+            () -> SearchPipelineService.innerDelete(deleteRequest, finalClusterState)
+        );
+        assertEquals("pipeline [_id] is missing", e.getMessage());
+    }
+
+    public void testDeletePipelinesWithWildcard() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        BytesArray definition = new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ] }");
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration("p1", definition, MediaTypeRegistry.JSON),
+                "p2",
+                new PipelineConfiguration("p2", definition, MediaTypeRegistry.JSON),
+                "q1",
+                new PipelineConfiguration("q1", definition, MediaTypeRegistry.JSON)
+            )
+        );
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        assertNotNull(searchPipelineService.getPipelines().get("p1"));
+        assertNotNull(searchPipelineService.getPipelines().get("p2"));
+        assertNotNull(searchPipelineService.getPipelines().get("q1"));
+
+        // Delete all pipelines starting with "p"
+        DeleteSearchPipelineRequest deleteRequest = new DeleteSearchPipelineRequest("p*");
+        previousState = clusterState;
+        clusterState = SearchPipelineService.innerDelete(deleteRequest, clusterState);
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        assertEquals(1, searchPipelineService.getPipelines().size());
+        assertNotNull(searchPipelineService.getPipelines().get("q1"));
+
+        // Prefix wildcard fails if no matches
+        final ClusterState finalClusterState = clusterState;
+        ResourceNotFoundException e = expectThrows(
+            ResourceNotFoundException.class,
+            () -> SearchPipelineService.innerDelete(deleteRequest, finalClusterState)
+        );
+        assertEquals("pipeline [p*] is missing", e.getMessage());
+
+        // Delete all removes remaining pipeline
+        DeleteSearchPipelineRequest deleteAllRequest = new DeleteSearchPipelineRequest("*");
+        previousState = clusterState;
+        clusterState = SearchPipelineService.innerDelete(deleteAllRequest, clusterState);
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        assertEquals(0, searchPipelineService.getPipelines().size());
+
+        // Delete all does not throw exception if no pipelines
+        SearchPipelineService.innerDelete(deleteAllRequest, clusterState);
+    }
+
+    public void testTransformRequest() throws Exception {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration(
+                    "p1",
+                    new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ] }"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+
+        int size = 10;
+        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder().query(new TermQueryBuilder("foo", "bar")).size(size);
+        SearchRequest request = new SearchRequest("_index").source(sourceBuilder).pipeline("p1");
+
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(request);
+
+        assertEquals(2 * size, pipelinedRequest.source().size());
+        assertEquals(size, request.source().size());
+
+        // This request doesn't specify a pipeline, it doesn't get transformed.
+        request = new SearchRequest("_index").source(sourceBuilder);
+        pipelinedRequest = searchPipelineService.resolvePipeline(request);
+        assertEquals(size, pipelinedRequest.source().size());
+    }
+
+    public void testTransformResponse() throws Exception {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration(
+                    "p1",
+                    new BytesArray("{\"response_processors\" : [ { \"fixed_score\": { \"score\" : 2 } } ] }"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+
+        int size = 10;
+        SearchHit[] hits = new SearchHit[size];
+        for (int i = 0; i < size; i++) {
+            hits[i] = new SearchHit(i, "doc" + i, Collections.emptyMap(), Collections.emptyMap());
+            hits[i].score(i);
+        }
+        SearchHits searchHits = new SearchHits(hits, new TotalHits(size * 2, TotalHits.Relation.EQUAL_TO), size);
+        SearchResponseSections searchResponseSections = new SearchResponseSections(searchHits, null, null, false, false, null, 0);
+        SearchResponse searchResponse = new SearchResponse(searchResponseSections, null, 1, 1, 0, 10, null, null);
+
+        // First try without specifying a pipeline, which should be a no-op.
+        SearchRequest searchRequest = new SearchRequest();
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+        SearchResponse notTransformedResponse = pipelinedRequest.transformResponse(searchResponse);
+        assertSame(searchResponse, notTransformedResponse);
+
+        // Now apply a pipeline
+        searchRequest = new SearchRequest().pipeline("p1");
+        pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+        SearchResponse transformedResponse = pipelinedRequest.transformResponse(searchResponse);
+        assertEquals(size, transformedResponse.getHits().getHits().length);
+        for (int i = 0; i < size; i++) {
+            assertEquals(2.0, transformedResponse.getHits().getHits()[i].getScore(), 0.0001f);
+        }
+    }
+
+    public void testTransformSearchPhase() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration(
+                    "p1",
+                    new BytesArray("{\"phase_results_processors\" : [ { \"max_score\" : { } } ]}"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        SearchPhaseController controller = new SearchPhaseController(
+            writableRegistry(),
+            s -> InternalAggregationTestCase.emptyReduceContextBuilder()
+        );
+        SearchPhaseContext searchPhaseContext = new MockSearchPhaseContext(10);
+        QueryPhaseResultConsumer searchPhaseResults = new QueryPhaseResultConsumer(
+            searchPhaseContext.getRequest(),
+            OpenSearchExecutors.newDirectExecutorService(),
+            new NoopCircuitBreaker(CircuitBreaker.REQUEST),
+            controller,
+            SearchProgressListener.NOOP,
+            writableRegistry(),
+            2,
+            exc -> {}
+        );
+
+        final QuerySearchResult querySearchResult = new QuerySearchResult();
+        querySearchResult.setShardIndex(1);
+        querySearchResult.topDocs(new TopDocsAndMaxScore(new TopDocs(null, new ScoreDoc[1]), 1f), null);
+        searchPhaseResults.consumeResult(querySearchResult, () -> {});
+
+        // First try without specifying a pipeline, which should be a no-op.
+        SearchRequest searchRequest = new SearchRequest();
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+        AtomicArray<SearchPhaseResult> notTransformedSearchPhaseResults = searchPhaseResults.getAtomicArray();
+        pipelinedRequest.transformSearchPhaseResults(
+            searchPhaseResults,
+            searchPhaseContext,
+            SearchPhaseName.QUERY.getName(),
+            SearchPhaseName.FETCH.getName()
+        );
+        assertSame(searchPhaseResults.getAtomicArray(), notTransformedSearchPhaseResults);
+
+        // Now set the pipeline as p1
+        searchRequest = new SearchRequest().pipeline("p1");
+        pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+
+        pipelinedRequest.transformSearchPhaseResults(
+            searchPhaseResults,
+            searchPhaseContext,
+            SearchPhaseName.QUERY.getName(),
+            SearchPhaseName.FETCH.getName()
+        );
+
+        List<SearchPhaseResult> resultAtomicArray = searchPhaseResults.getAtomicArray().asList();
+        assertEquals(1, resultAtomicArray.size());
+        // updating the maxScore
+        for (SearchPhaseResult result : resultAtomicArray) {
+            assertEquals(100f, result.queryResult().topDocs().maxScore, 0);
+        }
+
+        // Check Processor doesn't run for between other phases
+        searchRequest = new SearchRequest().pipeline("p1");
+        pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+        AtomicArray<SearchPhaseResult> notTransformedSearchPhaseResult = searchPhaseResults.getAtomicArray();
+        pipelinedRequest.transformSearchPhaseResults(
+            searchPhaseResults,
+            searchPhaseContext,
+            SearchPhaseName.DFS_QUERY.getName(),
+            SearchPhaseName.QUERY.getName()
+        );
+
+        assertSame(searchPhaseResults.getAtomicArray(), notTransformedSearchPhaseResult);
+    }
+
+    public void testGetPipelines() {
+        //
+        assertEquals(0, SearchPipelineService.innerGetPipelines(null, "p1").size());
+
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "p1",
+                new PipelineConfiguration(
+                    "p1",
+                    new BytesArray("{\"request_processors\" : [ { \"scale_request_size\": { \"scale\" : 2 } } ] }"),
+                    MediaTypeRegistry.JSON
+                ),
+                "p2",
+                new PipelineConfiguration(
+                    "p2",
+                    new BytesArray("{\"response_processors\" : [ { \"fixed_score\": { \"score\" : 2 } } ] }"),
+                    MediaTypeRegistry.JSON
+                ),
+                "p3",
+                new PipelineConfiguration(
+                    "p3",
+                    new BytesArray("{\"phase_results_processors\" : [ { \"max_score\" : { } } ]}"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+
+        // Return all when no ids specified
+        List<PipelineConfiguration> pipelines = SearchPipelineService.innerGetPipelines(metadata);
+        assertEquals(3, pipelines.size());
+        pipelines.sort(Comparator.comparing(PipelineConfiguration::getId));
+        assertEquals("p1", pipelines.get(0).getId());
+        assertEquals("p2", pipelines.get(1).getId());
+        assertEquals("p3", pipelines.get(2).getId());
+
+        // Get specific pipeline
+        pipelines = SearchPipelineService.innerGetPipelines(metadata, "p1");
+        assertEquals(1, pipelines.size());
+        assertEquals("p1", pipelines.get(0).getId());
+
+        // Get both pipelines explicitly
+        pipelines = SearchPipelineService.innerGetPipelines(metadata, "p1", "p2");
+        assertEquals(2, pipelines.size());
+        pipelines.sort(Comparator.comparing(PipelineConfiguration::getId));
+        assertEquals("p1", pipelines.get(0).getId());
+        assertEquals("p2", pipelines.get(1).getId());
+
+        // Match all
+        pipelines = SearchPipelineService.innerGetPipelines(metadata, "*");
+        assertEquals(3, pipelines.size());
+        pipelines.sort(Comparator.comparing(PipelineConfiguration::getId));
+        assertEquals("p1", pipelines.get(0).getId());
+        assertEquals("p2", pipelines.get(1).getId());
+        assertEquals("p3", pipelines.get(2).getId());
+
+        // Match prefix
+        pipelines = SearchPipelineService.innerGetPipelines(metadata, "p*");
+        assertEquals(3, pipelines.size());
+        pipelines.sort(Comparator.comparing(PipelineConfiguration::getId));
+        assertEquals("p1", pipelines.get(0).getId());
+        assertEquals("p2", pipelines.get(1).getId());
+        assertEquals("p3", pipelines.get(2).getId());
+    }
+
+    public void testValidatePipeline() throws Exception {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+
+        ProcessorInfo reqProcessor = new ProcessorInfo("scale_request_size");
+        ProcessorInfo rspProcessor = new ProcessorInfo("fixed_score");
+        ProcessorInfo injProcessor = new ProcessorInfo("max_score");
+        DiscoveryNode n1 = new DiscoveryNode("n1", buildNewFakeTransportAddress(), Version.CURRENT);
+        DiscoveryNode n2 = new DiscoveryNode("n2", buildNewFakeTransportAddress(), Version.CURRENT);
+        PutSearchPipelineRequest putRequest = new PutSearchPipelineRequest(
+            "p1",
+            new BytesArray(
+                "{"
+                    + "\"request_processors\": [{ \"scale_request_size\": { \"scale\" : 2 } }],"
+                    + "\"response_processors\": [{ \"fixed_score\": { \"score\" : 2 } }],"
+                    + "\"phase_results_processors\" : [ { \"max_score\" : { } } ]"
+                    + "}"
+            ),
+            MediaTypeRegistry.JSON
+        );
+
+        SearchPipelineInfo completePipelineInfo = new SearchPipelineInfo(
+            Map.of(Pipeline.REQUEST_PROCESSORS_KEY, List.of(reqProcessor), Pipeline.RESPONSE_PROCESSORS_KEY, List.of(rspProcessor))
+        );
+        SearchPipelineInfo incompletePipelineInfo = new SearchPipelineInfo(Map.of(Pipeline.REQUEST_PROCESSORS_KEY, List.of(reqProcessor)));
+        // One node is missing a processor
+        expectThrows(
+            OpenSearchParseException.class,
+            () -> searchPipelineService.validatePipeline(Map.of(n1, completePipelineInfo, n2, incompletePipelineInfo), putRequest)
+        );
+
+        // Discovery failed, no infos passed.
+        expectThrows(IllegalStateException.class, () -> searchPipelineService.validatePipeline(Collections.emptyMap(), putRequest));
+
+        // Invalid configuration in request
+        PutSearchPipelineRequest badPutRequest = new PutSearchPipelineRequest(
+            "p1",
+            new BytesArray(
+                "{"
+                    + "\"request_processors\": [{ \"scale_request_size\": { \"scale\" : \"banana\" } }],"
+                    + "\"response_processors\": [{ \"fixed_score\": { \"score\" : 2 } }]"
+                    + "}"
+            ),
+            MediaTypeRegistry.JSON
+        );
+        expectThrows(
+            ClassCastException.class,
+            () -> searchPipelineService.validatePipeline(Map.of(n1, completePipelineInfo, n2, completePipelineInfo), badPutRequest)
+        );
+
+        // Success
+        searchPipelineService.validatePipeline(Map.of(n1, completePipelineInfo, n2, completePipelineInfo), putRequest);
+    }
+
+    /**
+     * Tests a pipeline defined in the search request source.
+     */
+    public void testInlinePipeline() throws Exception {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        Map<String, Object> requestProcessorConfig = new HashMap<>();
+        requestProcessorConfig.put("scale", 2);
+        Map<String, Object> requestProcessorObject = new HashMap<>();
+        requestProcessorObject.put("scale_request_size", requestProcessorConfig);
+        pipelineSourceMap.put(Pipeline.REQUEST_PROCESSORS_KEY, List.of(requestProcessorObject));
+        Map<String, Object> responseProcessorConfig = new HashMap<>();
+        responseProcessorConfig.put("score", 2);
+        Map<String, Object> responseProcessorObject = new HashMap<>();
+        responseProcessorObject.put("fixed_score", responseProcessorConfig);
+        pipelineSourceMap.put(Pipeline.RESPONSE_PROCESSORS_KEY, List.of(responseProcessorObject));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().size(100).searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        // Verify pipeline
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+        Pipeline pipeline = pipelinedRequest.getPipeline();
+        assertEquals(SearchPipelineService.AD_HOC_PIPELINE_ID, pipeline.getId());
+        assertEquals(1, pipeline.getSearchRequestProcessors().size());
+        assertEquals(1, pipeline.getSearchResponseProcessors().size());
+
+        // Verify that pipeline transforms request
+        assertEquals(200, pipelinedRequest.source().size());
+
+        int size = 10;
+        SearchHit[] hits = new SearchHit[size];
+        for (int i = 0; i < size; i++) {
+            hits[i] = new SearchHit(i, "doc" + i, Collections.emptyMap(), Collections.emptyMap());
+            hits[i].score(i);
+        }
+        SearchHits searchHits = new SearchHits(hits, new TotalHits(size * 2, TotalHits.Relation.EQUAL_TO), size);
+        SearchResponseSections searchResponseSections = new SearchResponseSections(searchHits, null, null, false, false, null, 0);
+        SearchResponse searchResponse = new SearchResponse(searchResponseSections, null, 1, 1, 0, 10, null, null);
+
+        SearchResponse transformedResponse = pipeline.transformResponse(searchRequest, searchResponse);
+        for (int i = 0; i < size; i++) {
+            assertEquals(2.0, transformedResponse.getHits().getHits()[i].getScore(), 0.0001);
+        }
+    }
+
+    public void testInfo() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+        SearchPipelineInfo info = searchPipelineService.info();
+        assertTrue(info.containsProcessor(Pipeline.REQUEST_PROCESSORS_KEY, "scale_request_size"));
+        assertTrue(info.containsProcessor(Pipeline.RESPONSE_PROCESSORS_KEY, "fixed_score"));
+    }
+
+    public void testExceptionOnPipelineCreation() {
+        Map<String, Processor.Factory<SearchRequestProcessor>> badFactory = Map.of("bad_factory", (pf, t, i, f, c, ctx) -> {
+            throw new RuntimeException();
+        });
+        SearchPipelineService searchPipelineService = createWithProcessors(badFactory, Collections.emptyMap(), Collections.emptyMap());
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.REQUEST_PROCESSORS_KEY, List.of(Map.of("bad_factory", Collections.emptyMap())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        // Exception thrown when creating the pipeline
+        expectThrows(SearchPipelineProcessingException.class, () -> searchPipelineService.resolvePipeline(searchRequest));
+
+    }
+
+    public void testExceptionOnRequestProcessing() {
+        SearchRequestProcessor throwingRequestProcessor = new FakeRequestProcessor("throwing_request", null, null, false, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchRequestProcessor>> throwingRequestProcessorFactory = Map.of(
+            "throwing_request",
+            (pf, t, i, f, c, ctx) -> throwingRequestProcessor
+        );
+
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            throwingRequestProcessorFactory,
+            Collections.emptyMap(),
+            Collections.emptyMap()
+        );
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.REQUEST_PROCESSORS_KEY, List.of(Map.of("throwing_request", Collections.emptyMap())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        // Exception thrown when processing the request
+        expectThrows(SearchPipelineProcessingException.class, () -> searchPipelineService.resolvePipeline(searchRequest));
+    }
+
+    public void testExceptionOnResponseProcessing() throws Exception {
+        SearchResponseProcessor throwingResponseProcessor = new FakeResponseProcessor("throwing_response", null, null, false, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchResponseProcessor>> throwingResponseProcessorFactory = Map.of(
+            "throwing_response",
+            (pf, t, i, f, c, ctx) -> throwingResponseProcessor
+        );
+
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            Collections.emptyMap(),
+            throwingResponseProcessorFactory,
+            Collections.emptyMap()
+        );
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.RESPONSE_PROCESSORS_KEY, List.of(Map.of("throwing_response", new HashMap<>())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().size(100).searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+
+        SearchResponse response = new SearchResponse(null, null, 0, 0, 0, 0, null, null);
+        // Exception thrown when processing response
+        expectThrows(SearchPipelineProcessingException.class, () -> pipelinedRequest.transformResponse(response));
+    }
+
+    public void testCatchExceptionOnRequestProcessing() throws IllegalAccessException {
+        SearchRequestProcessor throwingRequestProcessor = new FakeRequestProcessor("throwing_request", null, null, true, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchRequestProcessor>> throwingRequestProcessorFactory = Map.of(
+            "throwing_request",
+            (pf, t, i, f, c, ctx) -> throwingRequestProcessor
+        );
+
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            throwingRequestProcessorFactory,
+            Collections.emptyMap(),
+            Collections.emptyMap()
+        );
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.REQUEST_PROCESSORS_KEY, List.of(Map.of("throwing_request", Collections.emptyMap())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        // Caught Exception thrown when processing the request and produced warn level logging message
+        try (MockLogAppender mockAppender = MockLogAppender.createForLoggers(LogManager.getLogger(Pipeline.class))) {
+            mockAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "test1",
+                    Pipeline.class.getCanonicalName(),
+                    Level.WARN,
+                    "The exception from request processor [throwing_request] in the search pipeline [_ad_hoc_pipeline] was ignored"
+                )
+            );
+            PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+            mockAppender.assertAllExpectationsMatched();
+        }
+    }
+
+    public void testCatchExceptionOnResponseProcessing() throws Exception {
+        SearchResponseProcessor throwingResponseProcessor = new FakeResponseProcessor("throwing_response", null, null, true, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchResponseProcessor>> throwingResponseProcessorFactory = Map.of(
+            "throwing_response",
+            (pf, t, i, f, c, ctx) -> throwingResponseProcessor
+        );
+
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            Collections.emptyMap(),
+            throwingResponseProcessorFactory,
+            Collections.emptyMap()
+        );
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.RESPONSE_PROCESSORS_KEY, List.of(Map.of("throwing_response", Collections.emptyMap())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().size(100).searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+
+        PipelinedRequest pipelinedRequest = searchPipelineService.resolvePipeline(searchRequest);
+
+        SearchResponse response = new SearchResponse(null, null, 0, 0, 0, 0, null, null);
+
+        // Caught Exception thrown when processing response and produced warn level logging message
+        try (MockLogAppender mockAppender = MockLogAppender.createForLoggers(LogManager.getLogger(Pipeline.class))) {
+            mockAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "test1",
+                    Pipeline.class.getCanonicalName(),
+                    Level.WARN,
+                    "The exception from response processor [throwing_response] in the search pipeline [_ad_hoc_pipeline] was ignored"
+                )
+            );
+            pipelinedRequest.transformResponse(response);
+            mockAppender.assertAllExpectationsMatched();
+        }
+    }
+
+    public void testStats() throws Exception {
+        SearchRequestProcessor throwingRequestProcessor = new FakeRequestProcessor("throwing_request", "1", null, false, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessors = Map.of(
+            "successful_request",
+            (pf, t, i, f, c, ctx) -> new FakeRequestProcessor("successful_request", "2", null, false, r -> {}),
+            "throwing_request",
+            (pf, t, i, f, c, ctx) -> throwingRequestProcessor
+        );
+        SearchResponseProcessor throwingResponseProcessor = new FakeResponseProcessor("throwing_response", "3", null, false, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessors = Map.of(
+            "successful_response",
+            (pf, t, i, f, c, ctx) -> new FakeResponseProcessor("successful_response", "4", null, false, r -> {}),
+            "throwing_response",
+            (pf, t, i, f, c, ctx) -> throwingResponseProcessor
+        );
+
+        SearchPipelineService searchPipelineService = getSearchPipelineService(requestProcessors, responseProcessors);
+
+        SearchRequest request = new SearchRequest();
+        SearchResponse response = new SearchResponse(null, null, 0, 0, 0, 0, null, null);
+
+        searchPipelineService.resolvePipeline(request.pipeline("good_request_pipeline")).transformResponse(response);
+        expectThrows(
+            SearchPipelineProcessingException.class,
+            () -> searchPipelineService.resolvePipeline(request.pipeline("bad_request_pipeline")).transformResponse(response)
+        );
+        searchPipelineService.resolvePipeline(request.pipeline("good_response_pipeline")).transformResponse(response);
+        expectThrows(
+            SearchPipelineProcessingException.class,
+            () -> searchPipelineService.resolvePipeline(request.pipeline("bad_response_pipeline")).transformResponse(response)
+        );
+
+        SearchPipelineStats stats = searchPipelineService.stats();
+        assertPipelineStats(stats.getTotalRequestStats(), 2, 1);
+        assertPipelineStats(stats.getTotalResponseStats(), 2, 1);
+        for (SearchPipelineStats.PerPipelineStats perPipelineStats : stats.getPipelineStats()) {
+            SearchPipelineStats.PipelineDetailStats detailStats = stats.getPerPipelineProcessorStats()
+                .get(perPipelineStats.getPipelineId());
+            switch (perPipelineStats.getPipelineId()) {
+                case "good_request_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 1, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 0, 0);
+                    assertEquals(1, detailStats.requestProcessorStats().size());
+                    assertEquals(0, detailStats.responseProcessorStats().size());
+                    assertEquals("successful_request:2", detailStats.requestProcessorStats().get(0).getProcessorName());
+                    assertEquals("successful_request", detailStats.requestProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.requestProcessorStats().get(0).getStats(), 1, 0);
+                    break;
+                case "bad_request_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 1, 1);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 0, 0);
+                    assertEquals(1, detailStats.requestProcessorStats().size());
+                    assertEquals(0, detailStats.responseProcessorStats().size());
+                    assertEquals("throwing_request:1", detailStats.requestProcessorStats().get(0).getProcessorName());
+                    assertEquals("throwing_request", detailStats.requestProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.requestProcessorStats().get(0).getStats(), 1, 1);
+                    break;
+                case "good_response_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 0, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 1, 0);
+                    assertEquals(0, detailStats.requestProcessorStats().size());
+                    assertEquals(1, detailStats.responseProcessorStats().size());
+                    assertEquals("successful_response:4", detailStats.responseProcessorStats().get(0).getProcessorName());
+                    assertEquals("successful_response", detailStats.responseProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.responseProcessorStats().get(0).getStats(), 1, 0);
+                    break;
+                case "bad_response_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 0, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 1, 1);
+                    assertEquals(0, detailStats.requestProcessorStats().size());
+                    assertEquals(1, detailStats.responseProcessorStats().size());
+                    assertEquals("throwing_response:3", detailStats.responseProcessorStats().get(0).getProcessorName());
+                    assertEquals("throwing_response", detailStats.responseProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.responseProcessorStats().get(0).getStats(), 1, 1);
+                    break;
+            }
+        }
+    }
+
+    public void testStatsEnabledIgnoreFailure() throws Exception {
+        SearchRequestProcessor throwingRequestProcessor = new FakeRequestProcessor("throwing_request", "1", null, true, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorsEnableIgnoreFailure = Map.of(
+            "successful_request",
+            (pf, t, i, f, c, ctx) -> new FakeRequestProcessor("successful_request", "2", null, true, r -> {}),
+            "throwing_request",
+            (pf, t, i, f, c, ctx) -> throwingRequestProcessor
+        );
+        SearchResponseProcessor throwingResponseProcessor = new FakeResponseProcessor("throwing_response", "3", null, true, r -> {
+            throw new RuntimeException();
+        });
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessorsEnableIgnoreFailure = Map.of(
+            "successful_response",
+            (pf, t, i, f, c, ctx) -> new FakeResponseProcessor("successful_response", "4", null, true, r -> {}),
+            "throwing_response",
+            (pf, t, i, f, c, ctx) -> throwingResponseProcessor
+        );
+
+        SearchPipelineService searchPipelineService = getSearchPipelineService(
+            requestProcessorsEnableIgnoreFailure,
+            responseProcessorsEnableIgnoreFailure
+        );
+
+        SearchRequest request = new SearchRequest();
+        SearchResponse response = new SearchResponse(null, null, 0, 0, 0, 0, null, null);
+
+        searchPipelineService.resolvePipeline(request.pipeline("good_request_pipeline")).transformResponse(response);
+        // Caught Exception here
+        searchPipelineService.resolvePipeline(request.pipeline("bad_request_pipeline")).transformResponse(response);
+        searchPipelineService.resolvePipeline(request.pipeline("good_response_pipeline")).transformResponse(response);
+        // Caught Exception here
+        searchPipelineService.resolvePipeline(request.pipeline("bad_response_pipeline")).transformResponse(response);
+
+        // when ignoreFailure enabled, the search pipelines will all succeed.
+        SearchPipelineStats stats = searchPipelineService.stats();
+        assertPipelineStats(stats.getTotalRequestStats(), 2, 0);
+        assertPipelineStats(stats.getTotalResponseStats(), 2, 0);
+
+        for (SearchPipelineStats.PerPipelineStats perPipelineStats : stats.getPipelineStats()) {
+            SearchPipelineStats.PipelineDetailStats detailStats = stats.getPerPipelineProcessorStats()
+                .get(perPipelineStats.getPipelineId());
+            switch (perPipelineStats.getPipelineId()) {
+                case "good_request_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 1, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 0, 0);
+                    assertEquals(1, detailStats.requestProcessorStats().size());
+                    assertEquals(0, detailStats.responseProcessorStats().size());
+                    assertEquals("successful_request:2", detailStats.requestProcessorStats().get(0).getProcessorName());
+                    assertEquals("successful_request", detailStats.requestProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.requestProcessorStats().get(0).getStats(), 1, 0);
+                    break;
+                case "bad_request_pipeline":
+                    // pipeline succeed when ignore failure is true
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 1, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 0, 0);
+                    assertEquals(1, detailStats.requestProcessorStats().size());
+                    assertEquals(0, detailStats.responseProcessorStats().size());
+                    assertEquals("throwing_request:1", detailStats.requestProcessorStats().get(0).getProcessorName());
+                    assertEquals("throwing_request", detailStats.requestProcessorStats().get(0).getProcessorType());
+                    // processor stats got 1 count and 1 failed
+                    assertPipelineStats(detailStats.requestProcessorStats().get(0).getStats(), 1, 1);
+                    break;
+                case "good_response_pipeline":
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 0, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 1, 0);
+                    assertEquals(0, detailStats.requestProcessorStats().size());
+                    assertEquals(1, detailStats.responseProcessorStats().size());
+                    assertEquals("successful_response:4", detailStats.responseProcessorStats().get(0).getProcessorName());
+                    assertEquals("successful_response", detailStats.responseProcessorStats().get(0).getProcessorType());
+                    assertPipelineStats(detailStats.responseProcessorStats().get(0).getStats(), 1, 0);
+                    break;
+                case "bad_response_pipeline":
+                    // pipeline succeed when ignore failure is true
+                    assertPipelineStats(perPipelineStats.getRequestStats(), 0, 0);
+                    assertPipelineStats(perPipelineStats.getResponseStats(), 1, 0);
+                    assertEquals(0, detailStats.requestProcessorStats().size());
+                    assertEquals(1, detailStats.responseProcessorStats().size());
+                    assertEquals("throwing_response:3", detailStats.responseProcessorStats().get(0).getProcessorName());
+                    assertEquals("throwing_response", detailStats.responseProcessorStats().get(0).getProcessorType());
+                    // processor stats got 1 count and 1 failed
+                    assertPipelineStats(detailStats.responseProcessorStats().get(0).getStats(), 1, 1);
+                    break;
+            }
+        }
+
+    }
+
+    private SearchPipelineService getSearchPipelineService(
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorsEnableIgnoreFailure,
+        Map<String, Processor.Factory<SearchResponseProcessor>> responseProcessorsEnableIgnoreFailure
+    ) {
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            requestProcessorsEnableIgnoreFailure,
+            responseProcessorsEnableIgnoreFailure,
+            Collections.emptyMap()
+        );
+
+        SearchPipelineMetadata metadata = new SearchPipelineMetadata(
+            Map.of(
+                "good_response_pipeline",
+                new PipelineConfiguration(
+                    "good_response_pipeline",
+                    new BytesArray("{\"response_processors\" : [ { \"successful_response\": {} } ] }"),
+                    MediaTypeRegistry.JSON
+                ),
+                "bad_response_pipeline",
+                new PipelineConfiguration(
+                    "bad_response_pipeline",
+                    new BytesArray("{\"response_processors\" : [ { \"throwing_response\": {} } ] }"),
+                    MediaTypeRegistry.JSON
+                ),
+                "good_request_pipeline",
+                new PipelineConfiguration(
+                    "good_request_pipeline",
+                    new BytesArray("{\"request_processors\" : [ { \"successful_request\": {} } ] }"),
+                    MediaTypeRegistry.JSON
+                ),
+                "bad_request_pipeline",
+                new PipelineConfiguration(
+                    "bad_request_pipeline",
+                    new BytesArray("{\"request_processors\" : [ { \"throwing_request\": {} } ] }"),
+                    MediaTypeRegistry.JSON
+                )
+            )
+        );
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        ClusterState previousState = clusterState;
+        clusterState = ClusterState.builder(clusterState)
+            .metadata(Metadata.builder().putCustom(SearchPipelineMetadata.TYPE, metadata))
+            .build();
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousState));
+        return searchPipelineService;
+    }
+
+    private static void assertPipelineStats(OperationStats stats, long count, long failed) {
+        assertEquals(stats.getCount(), count);
+        assertEquals(stats.getFailedCount(), failed);
+    }
+
+    public void testAdHocRejectingProcessor() {
+        String processorType = "ad_hoc_rejecting";
+        Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorFactories = Map.of(processorType, (pf, t, d, i, c, ctx) -> {
+            if (ctx.getPipelineSource() == Processor.PipelineSource.SEARCH_REQUEST) {
+                throw new IllegalArgumentException(processorType + " cannot be created as part of a pipeline defined in a search request");
+            }
+            return new FakeRequestProcessor(processorType, t, d, i, r -> {});
+        });
+
+        SearchPipelineService searchPipelineService = createWithProcessors(
+            requestProcessorFactories,
+            Collections.emptyMap(),
+            Collections.emptyMap()
+        );
+
+        String id = "_id";
+        SearchPipelineService.PipelineHolder pipeline = searchPipelineService.getPipelines().get(id);
+        assertNull(pipeline);
+        ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
+        PutSearchPipelineRequest putRequest = new PutSearchPipelineRequest(
+            id,
+            new BytesArray("{\"request_processors\":[" + " { \"" + processorType + "\": {}}" + "]}"),
+            MediaTypeRegistry.JSON
+        );
+        ClusterState previousClusterState = clusterState;
+        clusterState = SearchPipelineService.innerPut(putRequest, clusterState);
+        // The following line successfully creates the pipeline:
+        searchPipelineService.applyClusterState(new ClusterChangedEvent("", clusterState, previousClusterState));
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        pipelineSourceMap.put(Pipeline.REQUEST_PROCESSORS_KEY, List.of(Map.of(processorType, Collections.emptyMap())));
+
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+        expectThrows(SearchPipelineProcessingException.class, () -> searchPipelineService.resolvePipeline(searchRequest));
+    }
+
+    public void testExtraParameterInProcessorConfig() {
+        SearchPipelineService searchPipelineService = createWithProcessors();
+
+        Map<String, Object> pipelineSourceMap = new HashMap<>();
+        Map<String, Object> processorConfig = new HashMap<>(
+            Map.of("score", 1.0f, "tag", "my_tag", "comment", "I just like to add extra parameters so that I feel like I'm being heard.")
+        );
+        pipelineSourceMap.put(Pipeline.RESPONSE_PROCESSORS_KEY, List.of(Map.of("fixed_score", processorConfig)));
+        SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource().searchPipelineSource(pipelineSourceMap);
+        SearchRequest searchRequest = new SearchRequest().source(sourceBuilder);
+        try {
+            searchPipelineService.resolvePipeline(searchRequest);
+            fail("Exception should have been thrown");
+        } catch (SearchPipelineProcessingException e) {
+            assertTrue(
+                e.getMessage()
+                    .contains("processor [fixed_score:my_tag] doesn't support one or more provided configuration parameters: [comment]")
+            );
+        } catch (Exception e) {
+            fail("Wrong exception type: " + e.getClass());
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineStatsTests.java b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineStatsTests.java
new file mode 100644
index 0000000000000..2b904b5bc627f
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/pipeline/SearchPipelineStatsTests.java
@@ -0,0 +1,185 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pipeline;
+
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.metrics.OperationStats;
+import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+public class SearchPipelineStatsTests extends OpenSearchTestCase {
+    public void testSerializationRoundtrip() throws IOException {
+        SearchPipelineStats stats = createStats();
+        SearchPipelineStats deserialized;
+        try (BytesStreamOutput bytesStreamOutput = new BytesStreamOutput()) {
+            stats.writeTo(bytesStreamOutput);
+            try (StreamInput bytesStreamInput = bytesStreamOutput.bytes().streamInput()) {
+                deserialized = new SearchPipelineStats(bytesStreamInput);
+            }
+        }
+        assertEquals(stats, deserialized);
+    }
+
+    private static SearchPipelineStats createStats() {
+        return new SearchPipelineStats(
+            new OperationStats(1, 2, 3, 4),
+            new OperationStats(5, 6, 7, 8),
+            List.of(
+                new SearchPipelineStats.PerPipelineStats("p1", new OperationStats(9, 10, 11, 12), new OperationStats(13, 14, 15, 16)),
+                new SearchPipelineStats.PerPipelineStats("p2", new OperationStats(17, 18, 19, 20), new OperationStats(21, 22, 23, 24))
+
+            ),
+            Map.of(
+                "p1",
+                new SearchPipelineStats.PipelineDetailStats(
+                    List.of(new SearchPipelineStats.ProcessorStats("req1:a", "req1", new OperationStats(25, 26, 27, 28))),
+                    List.of(new SearchPipelineStats.ProcessorStats("rsp1:a", "rsp1", new OperationStats(29, 30, 31, 32)))
+                ),
+                "p2",
+                new SearchPipelineStats.PipelineDetailStats(
+                    List.of(
+                        new SearchPipelineStats.ProcessorStats("req1:a", "req1", new OperationStats(33, 34, 35, 36)),
+                        new SearchPipelineStats.ProcessorStats("req2", "req2", new OperationStats(37, 38, 39, 40))
+                    ),
+                    List.of()
+                )
+            )
+        );
+    }
+
+    public void testToXContent() throws IOException {
+        XContentBuilder actualBuilder = XContentBuilder.builder(JsonXContent.jsonXContent);
+        actualBuilder.startObject();
+        createStats().toXContent(actualBuilder, null);
+        actualBuilder.endObject();
+
+        String expected = "{"
+            + "  \"search_pipeline\" : {"
+            + "    \"total_request\" : {"
+            + "      \"count\" : 1,"
+            + "      \"time_in_millis\" : 2,"
+            + "      \"current\" : 3,"
+            + "      \"failed\" : 4"
+            + "    },"
+            + "    \"total_response\" : {"
+            + "      \"count\" : 5,"
+            + "      \"time_in_millis\" : 6,"
+            + "      \"current\" : 7,"
+            + "      \"failed\" : 8"
+            + "    },"
+            + "    \"pipelines\" : {"
+            + "      \"p1\" : {"
+            + "        \"request\" : {"
+            + "          \"count\" : 9,"
+            + "          \"time_in_millis\" : 10,"
+            + "          \"current\" : 11,"
+            + "          \"failed\" : 12"
+            + "        },"
+            + "        \"response\" : {"
+            + "          \"count\" : 13,"
+            + "          \"time_in_millis\" : 14,"
+            + "          \"current\" : 15,"
+            + "          \"failed\" : 16"
+            + "        },"
+            + "        \"request_processors\" : ["
+            + "          {"
+            + "            \"req1:a\" : {"
+            + "              \"type\" : \"req1\","
+            + "              \"stats\" : {"
+            + "                \"count\" : 25,"
+            + "                \"time_in_millis\" : 26,"
+            + "                \"current\" : 27,"
+            + "                \"failed\" : 28"
+            + "              }"
+            + "            }"
+            + "          }"
+            + "        ],"
+            + "        \"response_processors\" : ["
+            + "          {"
+            + "            \"rsp1:a\" : {"
+            + "              \"type\" : \"rsp1\","
+            + "              \"stats\" : {"
+            + "                \"count\" : 29,"
+            + "                \"time_in_millis\" : 30,"
+            + "                \"current\" : 31,"
+            + "                \"failed\" : 32"
+            + "              }"
+            + "            }"
+            + "          }"
+            + "        ]"
+            + "      },"
+            + "      \"p2\" : {"
+            + "        \"request\" : {"
+            + "          \"count\" : 17,"
+            + "          \"time_in_millis\" : 18,"
+            + "          \"current\" : 19,"
+            + "          \"failed\" : 20"
+            + "        },"
+            + "        \"response\" : {"
+            + "          \"count\" : 21,"
+            + "          \"time_in_millis\" : 22,"
+            + "          \"current\" : 23,"
+            + "          \"failed\" : 24"
+            + "        },"
+            + "        \"request_processors\" : ["
+            + "          {"
+            + "            \"req1:a\" : {"
+            + "              \"type\" : \"req1\","
+            + "              \"stats\" : {"
+            + "                \"count\" : 33,"
+            + "                \"time_in_millis\" : 34,"
+            + "                \"current\" : 35,"
+            + "                \"failed\" : 36"
+            + "              }"
+            + "            }"
+            + "          },"
+            + "          {"
+            + "            \"req2\" : {"
+            + "              \"type\" : \"req2\","
+            + "              \"stats\" : {"
+            + "                \"count\" : 37,"
+            + "                \"time_in_millis\" : 38,"
+            + "                \"current\" : 39,"
+            + "                \"failed\" : 40"
+            + "              }"
+            + "            }"
+            + "          }"
+            + "        ],"
+            + "        \"response_processors\" : [ ]"
+            + "      }"
+            + "    }"
+            + "  }"
+            + "}";
+
+        XContentParser expectedParser = JsonXContent.jsonXContent.createParser(
+            this.xContentRegistry(),
+            DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
+            expected
+        );
+        XContentBuilder expectedBuilder = XContentBuilder.builder(JsonXContent.jsonXContent);
+        expectedBuilder.generator().copyCurrentStructure(expectedParser);
+
+        assertEquals(
+            XContentHelper.convertToMap(BytesReference.bytes(expectedBuilder), false, (MediaType) MediaTypeRegistry.JSON),
+            XContentHelper.convertToMap(BytesReference.bytes(actualBuilder), false, (MediaType) MediaTypeRegistry.JSON)
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java b/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java
new file mode 100644
index 0000000000000..01d5979bfbf0c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java
@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pit;
+
+import org.opensearch.action.search.CreatePitRequest;
+import org.opensearch.action.search.CreatePitResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.search.RestCreatePitAction;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.client.NoOpNodeClient;
+import org.opensearch.test.rest.FakeRestChannel;
+import org.opensearch.test.rest.FakeRestRequest;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.hamcrest.Matchers.equalTo;
+
+/**
+ * Tests to verify behavior of create pit rest action
+ */
+public class RestCreatePitActionTests extends OpenSearchTestCase {
+    public void testRestCreatePit() throws Exception {
+        SetOnce<Boolean> createPitCalled = new SetOnce<>();
+        RestCreatePitAction action = new RestCreatePitAction();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void createPit(CreatePitRequest request, ActionListener<CreatePitResponse> listener) {
+                createPitCalled.set(true);
+                assertThat(request.getKeepAlive().getStringRep(), equalTo("1m"));
+                assertFalse(request.shouldAllowPartialPitCreation());
+            }
+        }) {
+            Map<String, String> params = new HashMap<>();
+            params.put("keep_alive", "1m");
+            params.put("allow_partial_pit_creation", "false");
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(params)
+                .withMethod(RestRequest.Method.POST)
+                .build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+            action.handleRequest(request, channel, nodeClient);
+
+            assertThat(createPitCalled.get(), equalTo(true));
+        }
+    }
+
+    public void testRestCreatePitDefaultPartialCreation() throws Exception {
+        SetOnce<Boolean> createPitCalled = new SetOnce<>();
+        RestCreatePitAction action = new RestCreatePitAction();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void createPit(CreatePitRequest request, ActionListener<CreatePitResponse> listener) {
+                createPitCalled.set(true);
+                assertThat(request.getKeepAlive().getStringRep(), equalTo("1m"));
+                assertTrue(request.shouldAllowPartialPitCreation());
+            }
+        }) {
+            Map<String, String> params = new HashMap<>();
+            params.put("keep_alive", "1m");
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(params)
+                .withMethod(RestRequest.Method.POST)
+                .build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+            action.handleRequest(request, channel, nodeClient);
+
+            assertThat(createPitCalled.get(), equalTo(true));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java b/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java
new file mode 100644
index 0000000000000..b60541825e3ed
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java
@@ -0,0 +1,133 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.pit;
+
+import org.opensearch.action.search.DeletePitRequest;
+import org.opensearch.action.search.DeletePitResponse;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.action.search.RestDeletePitAction;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.client.NoOpNodeClient;
+import org.opensearch.test.rest.FakeRestChannel;
+import org.opensearch.test.rest.FakeRestRequest;
+
+import java.util.Collections;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasSize;
+
+/**
+ * Tests to verify the behavior of rest delete pit action for list delete and delete all PIT endpoints
+ */
+public class RestDeletePitActionTests extends OpenSearchTestCase {
+    public void testParseDeletePitRequestWithInvalidJsonThrowsException() throws Exception {
+        RestDeletePitAction action = new RestDeletePitAction();
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
+            new BytesArray("{invalid_json}"),
+            MediaTypeRegistry.JSON
+        ).build();
+        Exception e = expectThrows(IllegalArgumentException.class, () -> action.prepareRequest(request, null));
+        assertThat(e.getMessage(), equalTo("Failed to parse request body"));
+    }
+
+    public void testDeletePitWithBody() throws Exception {
+        SetOnce<Boolean> pitCalled = new SetOnce<>();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void deletePits(DeletePitRequest request, ActionListener<DeletePitResponse> listener) {
+                pitCalled.set(true);
+                assertThat(request.getPitIds(), hasSize(1));
+                assertThat(request.getPitIds().get(0), equalTo("BODY"));
+            }
+        }) {
+            RestDeletePitAction action = new RestDeletePitAction();
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
+                new BytesArray("{\"pit_id\": [\"BODY\"]}"),
+                MediaTypeRegistry.JSON
+            ).build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+            action.handleRequest(request, channel, nodeClient);
+
+            assertThat(pitCalled.get(), equalTo(true));
+        }
+    }
+
+    public void testDeleteAllPit() throws Exception {
+        SetOnce<Boolean> pitCalled = new SetOnce<>();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void deletePits(DeletePitRequest request, ActionListener<DeletePitResponse> listener) {
+                pitCalled.set(true);
+                assertThat(request.getPitIds(), hasSize(1));
+                assertThat(request.getPitIds().get(0), equalTo("_all"));
+            }
+        }) {
+            RestDeletePitAction action = new RestDeletePitAction();
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withPath("/_all").build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+            action.handleRequest(request, channel, nodeClient);
+
+            assertThat(pitCalled.get(), equalTo(true));
+        }
+    }
+
+    public void testDeleteAllPitWithBody() {
+        SetOnce<Boolean> pitCalled = new SetOnce<>();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void deletePits(DeletePitRequest request, ActionListener<DeletePitResponse> listener) {
+                pitCalled.set(true);
+                assertThat(request.getPitIds(), hasSize(1));
+                assertThat(request.getPitIds().get(0), equalTo("_all"));
+            }
+        }) {
+            RestDeletePitAction action = new RestDeletePitAction();
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
+                new BytesArray("{\"pit_id\": [\"BODY\"]}"),
+                MediaTypeRegistry.JSON
+            ).withPath("/_all").build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+
+            IllegalArgumentException ex = expectThrows(
+                IllegalArgumentException.class,
+                () -> action.handleRequest(request, channel, nodeClient)
+            );
+            assertTrue(ex.getMessage().contains("request [GET /_all] does not support having a body"));
+        }
+    }
+
+    public void testDeletePitQueryStringParamsShouldThrowException() {
+        SetOnce<Boolean> pitCalled = new SetOnce<>();
+        try (NodeClient nodeClient = new NoOpNodeClient(this.getTestName()) {
+            @Override
+            public void deletePits(DeletePitRequest request, ActionListener<DeletePitResponse> listener) {
+                pitCalled.set(true);
+                assertThat(request.getPitIds(), hasSize(2));
+                assertThat(request.getPitIds().get(0), equalTo("QUERY_STRING"));
+                assertThat(request.getPitIds().get(1), equalTo("QUERY_STRING_1"));
+            }
+        }) {
+            RestDeletePitAction action = new RestDeletePitAction();
+            RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(
+                Collections.singletonMap("pit_id", "QUERY_STRING,QUERY_STRING_1")
+            ).build();
+            FakeRestChannel channel = new FakeRestChannel(request, false, 0);
+            IllegalArgumentException ex = expectThrows(
+                IllegalArgumentException.class,
+                () -> action.handleRequest(request, channel, nodeClient)
+            );
+            assertTrue(ex.getMessage().contains("unrecognized param"));
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/profile/ProfileResultTests.java b/server/src/test/java/org/opensearch/search/profile/ProfileResultTests.java
index b24e8f31dd020..ad63fa928dfcd 100644
--- a/server/src/test/java/org/opensearch/search/profile/ProfileResultTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/ProfileResultTests.java
@@ -32,13 +32,12 @@
 
 package org.opensearch.search.profile;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -49,14 +48,14 @@
 import java.util.Map;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class ProfileResultTests extends OpenSearchTestCase {
 
-    public static ProfileResult createTestItem(int depth) {
+    public static ProfileResult createTestItem(int depth, boolean concurrentSegmentSearchEnabled) {
         String type = randomAlphaOfLengthBetween(5, 10);
         String description = randomAlphaOfLengthBetween(5, 10);
         int breakdownsSize = randomIntBetween(0, 5);
@@ -77,13 +76,28 @@ public static ProfileResult createTestItem(int depth) {
         int childrenSize = depth > 0 ? randomIntBetween(0, 1) : 0;
         List<ProfileResult> children = new ArrayList<>(childrenSize);
         for (int i = 0; i < childrenSize; i++) {
-            children.add(createTestItem(depth - 1));
+            children.add(createTestItem(depth - 1, concurrentSegmentSearchEnabled));
+        }
+        if (concurrentSegmentSearchEnabled) {
+            return new ProfileResult(
+                type,
+                description,
+                breakdown,
+                debug,
+                randomNonNegativeLong(),
+                children,
+                randomNonNegativeLong(),
+                randomNonNegativeLong(),
+                randomNonNegativeLong()
+            );
+        } else {
+            return new ProfileResult(type, description, breakdown, debug, randomNonNegativeLong(), children);
         }
-        return new ProfileResult(type, description, breakdown, debug, randomNonNegativeLong(), children);
     }
 
     public void testFromXContent() throws IOException {
-        doFromXContentTestWithRandomFields(false);
+        doFromXContentTestWithRandomFields(false, false);
+        doFromXContentTestWithRandomFields(false, true);
     }
 
     /**
@@ -91,11 +105,12 @@ public void testFromXContent() throws IOException {
      * back to be forward compatible with additions to the xContent
      */
     public void testFromXContentWithRandomFields() throws IOException {
-        doFromXContentTestWithRandomFields(true);
+        doFromXContentTestWithRandomFields(true, false);
+        doFromXContentTestWithRandomFields(true, true);
     }
 
-    private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws IOException {
-        ProfileResult profileResult = createTestItem(2);
+    private void doFromXContentTestWithRandomFields(boolean addRandomFields, boolean concurrentSegmentSearchEnabled) throws IOException {
+        ProfileResult profileResult = createTestItem(2, concurrentSegmentSearchEnabled);
         XContentType xContentType = randomFrom(XContentType.values());
         boolean humanReadable = randomBoolean();
         BytesReference originalBytes = toShuffledXContent(profileResult, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
@@ -116,31 +131,16 @@ private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws
             assertNull(parser.nextToken());
         }
         assertEquals(profileResult.getTime(), parsed.getTime());
+        assertEquals(profileResult.getMaxSliceTime(), parsed.getMaxSliceTime());
+        assertEquals(profileResult.getMinSliceTime(), parsed.getMinSliceTime());
+        assertEquals(profileResult.getAvgSliceTime(), parsed.getAvgSliceTime());
         assertToXContentEquivalent(originalBytes, toXContent(parsed, xContentType, humanReadable), xContentType);
     }
 
     public void testToXContent() throws IOException {
         List<ProfileResult> children = new ArrayList<>();
-        children.add(
-            new ProfileResult(
-                "child1",
-                "desc1",
-                org.opensearch.common.collect.Map.of("key1", 100L),
-                org.opensearch.common.collect.Map.of(),
-                100L,
-                org.opensearch.common.collect.List.of()
-            )
-        );
-        children.add(
-            new ProfileResult(
-                "child2",
-                "desc2",
-                org.opensearch.common.collect.Map.of("key1", 123356L),
-                org.opensearch.common.collect.Map.of(),
-                123356L,
-                org.opensearch.common.collect.List.of()
-            )
-        );
+        children.add(new ProfileResult("child1", "desc1", Map.of("key1", 100L), Map.of(), 100L, List.of()));
+        children.add(new ProfileResult("child2", "desc2", Map.of("key1", 123356L), Map.of(), 123356L, List.of()));
         Map<String, Long> breakdown = new LinkedHashMap<>();
         breakdown.put("key1", 123456L);
         breakdown.put("stuff", 10000L);
@@ -182,7 +182,7 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  ]\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
         builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
@@ -222,17 +222,10 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  ]\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
-        result = new ProfileResult(
-            "profileName",
-            "some description",
-            org.opensearch.common.collect.Map.of("key1", 12345678L),
-            org.opensearch.common.collect.Map.of(),
-            12345678L,
-            org.opensearch.common.collect.List.of()
-        );
+        result = new ProfileResult("profileName", "some description", Map.of("key1", 12345678L), Map.of(), 12345678L, List.of());
         builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
         result.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertEquals(
@@ -245,16 +238,53 @@ public void testToXContent() throws IOException {
                 + "    \"key1\" : 12345678\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
+        );
+
+        result = new ProfileResult("profileName", "some description", Map.of("key1", 1234567890L), Map.of(), 1234567890L, List.of());
+        builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
+        result.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        assertEquals(
+            "{\n"
+                + "  \"type\" : \"profileName\",\n"
+                + "  \"description\" : \"some description\",\n"
+                + "  \"time\" : \"1.2s\",\n"
+                + "  \"time_in_nanos\" : 1234567890,\n"
+                + "  \"breakdown\" : {\n"
+                + "    \"key1\" : 1234567890\n"
+                + "  }\n"
+                + "}",
+            builder.toString()
+        );
+
+        result = new ProfileResult("profileName", "some description", Map.of("key1", 1234L), Map.of(), 1234L, List.of(), 321L, 123L, 222L);
+        builder = XContentFactory.jsonBuilder().prettyPrint();
+        result.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        assertEquals(
+            "{\n"
+                + "  \"type\" : \"profileName\",\n"
+                + "  \"description\" : \"some description\",\n"
+                + "  \"time_in_nanos\" : 1234,\n"
+                + "  \"max_slice_time_in_nanos\" : 321,\n"
+                + "  \"min_slice_time_in_nanos\" : 123,\n"
+                + "  \"avg_slice_time_in_nanos\" : 222,\n"
+                + "  \"breakdown\" : {\n"
+                + "    \"key1\" : 1234\n"
+                + "  }\n"
+                + "}",
+            builder.toString()
         );
 
         result = new ProfileResult(
             "profileName",
             "some description",
-            org.opensearch.common.collect.Map.of("key1", 1234567890L),
-            org.opensearch.common.collect.Map.of(),
+            Map.of("key1", 1234567890L),
+            Map.of(),
             1234567890L,
-            org.opensearch.common.collect.List.of()
+            List.of(),
+            87654321L,
+            12345678L,
+            54637281L
         );
         builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
         result.toXContent(builder, ToXContent.EMPTY_PARAMS);
@@ -263,12 +293,35 @@ public void testToXContent() throws IOException {
                 + "  \"type\" : \"profileName\",\n"
                 + "  \"description\" : \"some description\",\n"
                 + "  \"time\" : \"1.2s\",\n"
+                + "  \"max_slice_time\" : \"87.6ms\",\n"
+                + "  \"min_slice_time\" : \"12.3ms\",\n"
+                + "  \"avg_slice_time\" : \"54.6ms\",\n"
                 + "  \"time_in_nanos\" : 1234567890,\n"
+                + "  \"max_slice_time_in_nanos\" : 87654321,\n"
+                + "  \"min_slice_time_in_nanos\" : 12345678,\n"
+                + "  \"avg_slice_time_in_nanos\" : 54637281,\n"
                 + "  \"breakdown\" : {\n"
                 + "    \"key1\" : 1234567890\n"
                 + "  }\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
+
+    }
+
+    public void testRemoveStartTimeFields() {
+        Map<String, Long> breakdown = new HashMap<>();
+        breakdown.put("initialize_start_time", 123456L);
+        breakdown.put("initialize_count", 1L);
+        breakdown.put("initialize", 654321L);
+        Map<String, Long> modifiedBreakdown = new LinkedHashMap<>(breakdown);
+        assertEquals(3, modifiedBreakdown.size());
+        assertEquals(123456L, (long) modifiedBreakdown.get("initialize_start_time"));
+        assertEquals(1L, (long) modifiedBreakdown.get("initialize_count"));
+        assertEquals(654321L, (long) modifiedBreakdown.get("initialize"));
+        ProfileResult.removeStartTimeFields(modifiedBreakdown);
+        assertFalse(modifiedBreakdown.containsKey("initialize_start_time"));
+        assertTrue(modifiedBreakdown.containsKey("initialize_count"));
+        assertTrue(modifiedBreakdown.containsKey("initialize"));
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/profile/SearchProfileShardResultsTests.java b/server/src/test/java/org/opensearch/search/profile/SearchProfileShardResultsTests.java
index 7549e50432df9..71511652c0856 100644
--- a/server/src/test/java/org/opensearch/search/profile/SearchProfileShardResultsTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/SearchProfileShardResultsTests.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.profile;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.profile.aggregation.AggregationProfileShardResult;
 import org.opensearch.search.profile.aggregation.AggregationProfileShardResultTests;
 import org.opensearch.search.profile.query.QueryProfileShardResult;
@@ -49,9 +49,9 @@
 import java.util.Map;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureFieldName;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
diff --git a/server/src/test/java/org/opensearch/search/profile/TimerTests.java b/server/src/test/java/org/opensearch/search/profile/TimerTests.java
index deed451c21933..5997292eb8f56 100644
--- a/server/src/test/java/org/opensearch/search/profile/TimerTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/TimerTests.java
@@ -71,10 +71,14 @@ long nanoTime() {
                 return time += 42;
             }
         };
-        for (int i = 1; i < 100000; ++i) {
+        t.start();
+        t.stop();
+        long timerStartTime = t.getEarliestTimerStartTime();
+        for (int i = 2; i < 100000; ++i) {
             t.start();
             t.stop();
             assertEquals(i, t.getCount());
+            assertEquals(timerStartTime, t.getEarliestTimerStartTime());
             // Make sure the cumulated timing is 42 times the number of calls as expected
             assertEquals(i * 42L, t.getApproximateTiming());
         }
diff --git a/server/src/test/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResultTests.java b/server/src/test/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResultTests.java
index 2827bcd098bcc..1b4f34fe3e517 100644
--- a/server/src/test/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResultTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/aggregation/AggregationProfileShardResultTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.search.profile.aggregation;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.profile.ProfileResult;
 import org.opensearch.search.profile.ProfileResultTests;
 import org.opensearch.test.OpenSearchTestCase;
@@ -48,7 +49,7 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class AggregationProfileShardResultTests extends OpenSearchTestCase {
@@ -57,7 +58,7 @@ public static AggregationProfileShardResult createTestItem(int depth) {
         int size = randomIntBetween(0, 5);
         List<ProfileResult> aggProfileResults = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
-            aggProfileResults.add(ProfileResultTests.createTestItem(1));
+            aggProfileResults.add(ProfileResultTests.createTestItem(depth, false));
         }
         return new AggregationProfileShardResult(aggProfileResults);
     }
@@ -87,11 +88,11 @@ public void testToXContent() throws IOException {
         breakdown.put("timing2", 4000L);
         Map<String, Object> debug = new LinkedHashMap<>();
         debug.put("stuff", "stuff");
-        debug.put("other_stuff", org.opensearch.common.collect.List.of("foo", "bar"));
+        debug.put("other_stuff", List.of("foo", "bar"));
         ProfileResult profileResult = new ProfileResult("someType", "someDescription", breakdown, debug, 6000L, Collections.emptyList());
         profileResults.add(profileResult);
         AggregationProfileShardResult aggProfileResults = new AggregationProfileShardResult(profileResults);
-        BytesReference xContent = toXContent(aggProfileResults, XContentType.JSON, false);
+        BytesReference xContent = toXContent(aggProfileResults, MediaTypeRegistry.JSON, false);
         assertEquals(
             "{\"aggregations\":["
                 + "{\"type\":\"someType\","
@@ -104,7 +105,7 @@ public void testToXContent() throws IOException {
             xContent.utf8ToString()
         );
 
-        xContent = toXContent(aggProfileResults, XContentType.JSON, true);
+        xContent = toXContent(aggProfileResults, MediaTypeRegistry.JSON, true);
         assertEquals(
             "{\"aggregations\":["
                 + "{\"type\":\"someType\","
diff --git a/server/src/test/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfilerTests.java b/server/src/test/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfilerTests.java
new file mode 100644
index 0000000000000..e36b65f0a7b69
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/profile/aggregation/ConcurrentAggregationProfilerTests.java
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.profile.aggregation;
+
+import org.opensearch.search.profile.ProfileResult;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ConcurrentAggregationProfilerTests extends OpenSearchTestCase {
+
+    public static List<ProfileResult> createConcurrentSearchProfileTree() {
+        List<ProfileResult> tree = new ArrayList<>();
+        // Aggregation
+        tree.add(
+            new ProfileResult(
+                "NumericTermsAggregator",
+                "test_scoped_agg",
+                new LinkedHashMap<>(),
+                new HashMap<>(),
+                10847417L,
+                List.of(
+                    new ProfileResult(
+                        "GlobalOrdinalsStringTermsAggregator",
+                        "test_terms",
+                        new LinkedHashMap<>(),
+                        new HashMap<>(),
+                        3359835L,
+                        List.of(),
+                        1490667L,
+                        1180123L,
+                        1240676L
+                    )
+                ),
+                94582L,
+                18667L,
+                211749L
+            )
+        );
+        tree.add(
+            new ProfileResult(
+                "NumericTermsAggregator",
+                "test_scoped_agg",
+                new LinkedHashMap<>(),
+                new HashMap<>(),
+                10776655L,
+                List.of(
+                    new ProfileResult(
+                        "GlobalOrdinalsStringTermsAggregator",
+                        "test_terms",
+                        new LinkedHashMap<>(),
+                        new HashMap<>(),
+                        3359567L,
+                        List.of(),
+                        1390554L,
+                        1180321L,
+                        1298776L
+                    )
+                ),
+                94560L,
+                11237L,
+                236440L
+            )
+        );
+        // Global Aggregation
+        tree.add(
+            new ProfileResult(
+                "GlobalAggregator",
+                "test_global_agg",
+                new LinkedHashMap<>(),
+                new HashMap<>(),
+                19631335L,
+                List.of(),
+                563002L,
+                142210L,
+                1216631L
+            )
+        );
+        tree.add(
+            new ProfileResult(
+                "GlobalAggregator",
+                "test_global_agg",
+                new LinkedHashMap<>(),
+                new HashMap<>(),
+                19634567L,
+                List.of(),
+                563333L,
+                146783L,
+                1496600L
+            )
+        );
+        return tree;
+    }
+
+    public void testBuildTimeStatsBreakdownMap() {
+        List<ProfileResult> tree = createConcurrentSearchProfileTree();
+        Map<String, Long> breakdown = new HashMap<>();
+        Map<String, Long> timeStatsMap = new HashMap<>();
+        timeStatsMap.put("max_initialize", 30L);
+        timeStatsMap.put("min_initialize", 10L);
+        timeStatsMap.put("avg_initialize", 60L);
+        ConcurrentAggregationProfiler.buildBreakdownMap(tree.size(), breakdown, timeStatsMap, "initialize");
+        assertTrue(breakdown.containsKey("max_initialize"));
+        assertTrue(breakdown.containsKey("min_initialize"));
+        assertTrue(breakdown.containsKey("avg_initialize"));
+        assertEquals(30L, (long) breakdown.get("max_initialize"));
+        assertEquals(10L, (long) breakdown.get("min_initialize"));
+        assertEquals(15L, (long) breakdown.get("avg_initialize"));
+    }
+
+    public void testBuildCountStatsBreakdownMap() {
+        List<ProfileResult> tree = createConcurrentSearchProfileTree();
+        Map<String, Long> breakdown = new HashMap<>();
+        Map<String, Long> countStatsMap = new HashMap<>();
+        countStatsMap.put("max_collect_count", 3L);
+        countStatsMap.put("min_collect_count", 1L);
+        countStatsMap.put("avg_collect_count", 6L);
+        ConcurrentAggregationProfiler.buildBreakdownMap(tree.size(), breakdown, countStatsMap, "collect_count");
+        assertTrue(breakdown.containsKey("max_collect_count"));
+        assertTrue(breakdown.containsKey("min_collect_count"));
+        assertTrue(breakdown.containsKey("avg_collect_count"));
+        assertEquals(3L, (long) breakdown.get("max_collect_count"));
+        assertEquals(1L, (long) breakdown.get("min_collect_count"));
+        assertEquals(1L, (long) breakdown.get("avg_collect_count"));
+    }
+
+    public void testBuildBreakdownStatsMap() {
+        Map<String, Long> statsMap = new HashMap<>();
+        ConcurrentAggregationProfiler.buildBreakdownStatsMap(
+            statsMap,
+            new ProfileResult("NumericTermsAggregator", "desc", Map.of("initialize", 100L), Map.of(), 130L, List.of()),
+            "initialize"
+        );
+        assertTrue(statsMap.containsKey("max_initialize"));
+        assertTrue(statsMap.containsKey("min_initialize"));
+        assertTrue(statsMap.containsKey("avg_initialize"));
+        assertEquals(100L, (long) statsMap.get("max_initialize"));
+        assertEquals(100L, (long) statsMap.get("min_initialize"));
+        assertEquals(100L, (long) statsMap.get("avg_initialize"));
+        ConcurrentAggregationProfiler.buildBreakdownStatsMap(
+            statsMap,
+            new ProfileResult("NumericTermsAggregator", "desc", Map.of("initialize", 50L), Map.of(), 120L, List.of()),
+            "initialize"
+        );
+        assertEquals(100L, (long) statsMap.get("max_initialize"));
+        assertEquals(50L, (long) statsMap.get("min_initialize"));
+        assertEquals(150L, (long) statsMap.get("avg_initialize"));
+    }
+
+    public void testGetSliceLevelAggregationMap() {
+        List<ProfileResult> tree = createConcurrentSearchProfileTree();
+        Map<String, List<ProfileResult>> aggregationMap = ConcurrentAggregationProfiler.getSliceLevelAggregationMap(tree);
+        assertEquals(2, aggregationMap.size());
+        assertTrue(aggregationMap.containsKey("test_scoped_agg"));
+        assertTrue(aggregationMap.containsKey("test_global_agg"));
+        assertEquals(2, aggregationMap.get("test_scoped_agg").size());
+        assertEquals(2, aggregationMap.get("test_global_agg").size());
+        for (int slice_id : new int[] { 0, 1 }) {
+            assertEquals(1, aggregationMap.get("test_scoped_agg").get(slice_id).getProfiledChildren().size());
+            assertEquals(
+                "test_terms",
+                aggregationMap.get("test_scoped_agg").get(slice_id).getProfiledChildren().get(0).getLuceneDescription()
+            );
+            assertEquals(0, aggregationMap.get("test_global_agg").get(slice_id).getProfiledChildren().size());
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/profile/query/CollectorResultTests.java b/server/src/test/java/org/opensearch/search/profile/query/CollectorResultTests.java
index a8f34ae29d959..b6a20359c7a0b 100644
--- a/server/src/test/java/org/opensearch/search/profile/query/CollectorResultTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/query/CollectorResultTests.java
@@ -32,13 +32,12 @@
 
 package org.opensearch.search.profile.query;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -46,14 +45,14 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class CollectorResultTests extends OpenSearchTestCase {
 
-    public static CollectorResult createTestItem(int depth) {
+    public static CollectorResult createTestItem(int depth, boolean concurrentSearchEnabled) {
         String name = randomAlphaOfLengthBetween(5, 10);
         String reason = randomAlphaOfLengthBetween(5, 10);
         long time = randomNonNegativeLong();
@@ -61,26 +60,47 @@ public static CollectorResult createTestItem(int depth) {
             // also often use relatively "small" values, otherwise we will mostly test huge longs
             time = time % 100000;
         }
+        long reduceTime = time;
+        long maxSliceTime = time;
+        long minSliceTime = time;
+        long avgSliceTime = time;
+        int sliceCount = randomIntBetween(1, 10);
         int size = randomIntBetween(0, 5);
         List<CollectorResult> children = new ArrayList<>(size);
         if (depth > 0) {
             for (int i = 0; i < size; i++) {
-                children.add(createTestItem(depth - 1));
+                children.add(createTestItem(depth - 1, concurrentSearchEnabled));
             }
         }
+
+        if (concurrentSearchEnabled) {
+            return new CollectorResult(
+                "defaultCollectorManager",
+                "some reason",
+                time,
+                reduceTime,
+                maxSliceTime,
+                minSliceTime,
+                avgSliceTime,
+                sliceCount,
+                children
+            );
+        }
         return new CollectorResult(name, reason, time, children);
     }
 
     public void testFromXContent() throws IOException {
-        doFromXContentTestWithRandomFields(false);
+        doFromXContentTestWithRandomFields(false, false);
+        doFromXContentTestWithRandomFields(false, true);
     }
 
     public void testFromXContentWithRandomFields() throws IOException {
-        doFromXContentTestWithRandomFields(true);
+        doFromXContentTestWithRandomFields(true, false);
+        doFromXContentTestWithRandomFields(true, true);
     }
 
-    private void doFromXContentTestWithRandomFields(boolean addRandomFields) throws IOException {
-        CollectorResult collectorResult = createTestItem(1);
+    private void doFromXContentTestWithRandomFields(boolean addRandomFields, boolean concurrentSearchEnabled) throws IOException {
+        CollectorResult collectorResult = createTestItem(1, concurrentSearchEnabled);
         XContentType xContentType = randomFrom(XContentType.values());
         boolean humanReadable = randomBoolean();
         BytesReference originalBytes = toShuffledXContent(collectorResult, xContentType, ToXContent.EMPTY_PARAMS, humanReadable);
@@ -123,7 +143,7 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  ]\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
         builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
@@ -149,7 +169,7 @@ public void testToXContent() throws IOException {
                 + "    }\n"
                 + "  ]\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
         result = new CollectorResult("collectorName", "some reason", 12345678L, Collections.emptyList());
@@ -162,7 +182,7 @@ public void testToXContent() throws IOException {
                 + "  \"time\" : \"12.3ms\",\n"
                 + "  \"time_in_nanos\" : 12345678\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
         );
 
         result = new CollectorResult("collectorName", "some reason", 1234567890L, Collections.emptyList());
@@ -175,7 +195,35 @@ public void testToXContent() throws IOException {
                 + "  \"time\" : \"1.2s\",\n"
                 + "  \"time_in_nanos\" : 1234567890\n"
                 + "}",
-            Strings.toString(builder)
+            builder.toString()
+        );
+
+        result = new CollectorResult(
+            "defaultCollectorManager",
+            "some reason",
+            123456789L,
+            123456789L,
+            123456789L,
+            123456789L,
+            123456789L,
+            3,
+            Collections.emptyList()
+        );
+        builder = XContentFactory.jsonBuilder().prettyPrint().humanReadable(true);
+        result.toXContent(builder, ToXContent.EMPTY_PARAMS);
+        assertEquals(
+            "{\n"
+                + "  \"name\" : \"defaultCollectorManager\",\n"
+                + "  \"reason\" : \"some reason\",\n"
+                + "  \"time\" : \"123.4ms\",\n"
+                + "  \"time_in_nanos\" : 123456789,\n"
+                + "  \"reduce_time_in_nanos\" : 123456789,\n"
+                + "  \"max_slice_time_in_nanos\" : 123456789,\n"
+                + "  \"min_slice_time_in_nanos\" : 123456789,\n"
+                + "  \"avg_slice_time_in_nanos\" : 123456789,\n"
+                + "  \"slice_count\" : 3\n"
+                + "}",
+            builder.toString()
         );
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/profile/query/QueryProfileShardResultTests.java b/server/src/test/java/org/opensearch/search/profile/query/QueryProfileShardResultTests.java
index d9b3f8bd77009..5281c36fb66e2 100644
--- a/server/src/test/java/org/opensearch/search/profile/query/QueryProfileShardResultTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/query/QueryProfileShardResultTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.profile.query;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.search.profile.ProfileResult;
 import org.opensearch.search.profile.ProfileResultTests;
 import org.opensearch.test.OpenSearchTestCase;
@@ -45,7 +45,7 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public class QueryProfileShardResultTests extends OpenSearchTestCase {
@@ -54,9 +54,9 @@ public static QueryProfileShardResult createTestItem() {
         int size = randomIntBetween(0, 5);
         List<ProfileResult> queryProfileResults = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
-            queryProfileResults.add(ProfileResultTests.createTestItem(1));
+            queryProfileResults.add(ProfileResultTests.createTestItem(1, false));
         }
-        CollectorResult profileCollector = CollectorResultTests.createTestItem(2);
+        CollectorResult profileCollector = CollectorResultTests.createTestItem(2, false);
         long rewriteTime = randomNonNegativeLong();
         if (randomBoolean()) {
             rewriteTime = rewriteTime % 1000; // make sure to often test this with small values too
diff --git a/server/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java b/server/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java
index afaab15e1431e..a278e7004cc93 100644
--- a/server/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java
+++ b/server/src/test/java/org/opensearch/search/profile/query/QueryProfilerTests.java
@@ -41,7 +41,6 @@
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.Explanation;
 import org.apache.lucene.search.IndexSearcher;
@@ -50,7 +49,6 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.QueryVisitor;
-import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.ScorerSupplier;
@@ -59,9 +57,13 @@
 import org.apache.lucene.search.TotalHitCountCollector;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.tests.util.TestUtil;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.index.shard.IndexShard;
 import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.profile.ProfileResult;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
@@ -79,9 +81,10 @@
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class QueryProfilerTests extends OpenSearchTestCase {
-
     private Directory dir;
     private IndexReader reader;
     private ContextIndexSearcher searcher;
@@ -114,13 +117,19 @@ public void setUp() throws Exception {
         }
         reader = w.getReader();
         w.close();
+
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
         searcher = new ContextIndexSearcher(
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             ALWAYS_CACHE_POLICY,
             true,
-            executor
+            executor,
+            searchContext
         );
     }
 
@@ -145,7 +154,7 @@ public void tearDown() throws Exception {
     }
 
     public void testBasic() throws IOException {
-        QueryProfiler profiler = new QueryProfiler(searcher.allowConcurrentSegmentSearch());
+        QueryProfiler profiler = new QueryProfiler(executor != null);
         searcher.setProfiler(profiler);
         Query query = new TermQuery(new Term("foo", "bar"));
         searcher.search(query, 1);
@@ -171,7 +180,7 @@ public void testBasic() throws IOException {
     }
 
     public void testNoScoring() throws IOException {
-        QueryProfiler profiler = new QueryProfiler(searcher.allowConcurrentSegmentSearch());
+        QueryProfiler profiler = new QueryProfiler(executor != null);
         searcher.setProfiler(profiler);
         Query query = new TermQuery(new Term("foo", "bar"));
         searcher.search(query, 1, Sort.INDEXORDER); // scores are not needed
@@ -197,7 +206,7 @@ public void testNoScoring() throws IOException {
     }
 
     public void testUseIndexStats() throws IOException {
-        QueryProfiler profiler = new QueryProfiler(searcher.allowConcurrentSegmentSearch());
+        QueryProfiler profiler = new QueryProfiler(executor != null);
         searcher.setProfiler(profiler);
         Query query = new TermQuery(new Term("foo", "bar"));
         searcher.count(query); // will use index stats
@@ -211,7 +220,7 @@ public void testUseIndexStats() throws IOException {
     }
 
     public void testApproximations() throws IOException {
-        QueryProfiler profiler = new QueryProfiler(searcher.allowConcurrentSegmentSearch());
+        QueryProfiler profiler = new QueryProfiler(executor != null);
         searcher.setProfiler(profiler);
         Query query = new RandomApproximationQuery(new TermQuery(new Term("foo", "bar")), random());
         searcher.count(query);
@@ -240,14 +249,19 @@ public void testCollector() throws IOException {
         TotalHitCountCollector collector = new TotalHitCountCollector();
         ProfileCollector profileCollector = new ProfileCollector(collector);
         assertEquals(0, profileCollector.getTime());
+        assertEquals(0, profileCollector.getSliceStartTime());
         final LeafCollector leafCollector = profileCollector.getLeafCollector(reader.leaves().get(0));
         assertThat(profileCollector.getTime(), greaterThan(0L));
+        assertThat(profileCollector.getSliceStartTime(), greaterThan(0L));
         long time = profileCollector.getTime();
+        long sliceStartTime = profileCollector.getSliceStartTime();
         leafCollector.setScorer(null);
         assertThat(profileCollector.getTime(), greaterThan(time));
+        assertEquals(sliceStartTime, profileCollector.getSliceStartTime());
         time = profileCollector.getTime();
         leafCollector.collect(0);
         assertThat(profileCollector.getTime(), greaterThan(time));
+        assertEquals(sliceStartTime, profileCollector.getSliceStartTime());
     }
 
     private static class DummyQuery extends Query {
diff --git a/server/src/test/java/org/opensearch/search/query/QueryPhaseTests.java b/server/src/test/java/org/opensearch/search/query/QueryPhaseTests.java
index b87c11dce5be2..7d350847b50e5 100644
--- a/server/src/test/java/org/opensearch/search/query/QueryPhaseTests.java
+++ b/server/src/test/java/org/opensearch/search/query/QueryPhaseTests.java
@@ -32,6 +32,8 @@
 
 package org.opensearch.search.query;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field.Store;
@@ -39,6 +41,7 @@
 import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.SortedDocValuesField;
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
@@ -48,9 +51,7 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.NoMergePolicy;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
-import org.opensearch.lucene.queries.MinDocQuery;
 import org.apache.lucene.queries.spans.SpanNearQuery;
 import org.apache.lucene.queries.spans.SpanTermQuery;
 import org.apache.lucene.search.BooleanClause.Occur;
@@ -77,49 +78,81 @@
 import org.apache.lucene.search.TotalHitCountCollector;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.Weight;
+import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
 import org.apache.lucene.search.join.BitSetProducer;
 import org.apache.lucene.search.join.ScoreMode;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
 import org.opensearch.action.search.SearchShardTask;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.TaskCancelledException;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberType;
 import org.opensearch.index.query.ParsedQuery;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.search.OpenSearchToParentBlockJoinQuery;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.lucene.queries.MinDocQuery;
 import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.collapse.CollapseBuilder;
 import org.opensearch.search.internal.ContextIndexSearcher;
 import org.opensearch.search.internal.ScrollContext;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.sort.SortAndFormats;
-import org.opensearch.tasks.TaskCancelledException;
 import org.opensearch.test.TestSearchContext;
+import org.opensearch.threadpool.ThreadPool;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.opensearch.search.query.TopDocsCollectorContext.hasInfMaxScore;
+import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.instanceOf;
-import static org.opensearch.search.query.TopDocsCollectorContext.hasInfMaxScore;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
 import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
 
 public class QueryPhaseTests extends IndexShardTestCase {
-
     private IndexShard indexShard;
+    private final ExecutorService executor;
+    private final QueryPhaseSearcher queryPhaseSearcher;
+
+    @ParametersFactory
+    public static Collection<Object[]> concurrency() {
+        return Arrays.asList(
+            new Object[] { 0, QueryPhase.DEFAULT_QUERY_PHASE_SEARCHER },
+            new Object[] { 5, new ConcurrentQueryPhaseSearcher() }
+        );
+    }
+
+    public QueryPhaseTests(int concurrency, QueryPhaseSearcher queryPhaseSearcher) {
+        this.executor = (concurrency > 0) ? Executors.newFixedThreadPool(concurrency) : null;
+        this.queryPhaseSearcher = queryPhaseSearcher;
+    }
 
     @Override
     public Settings threadPoolSettings() {
@@ -135,21 +168,26 @@ public void setUp() throws Exception {
     @Override
     public void tearDown() throws Exception {
         super.tearDown();
+        if (executor != null) {
+            ThreadPool.terminate(executor, 10, TimeUnit.SECONDS);
+        }
         closeShards(indexShard);
     }
 
     private void countTestCase(Query query, IndexReader reader, boolean shouldCollectSearch, boolean shouldCollectCount) throws Exception {
-        ContextIndexSearcher searcher = shouldCollectSearch ? newContextSearcher(reader) : newEarlyTerminationContextSearcher(reader, 0);
+        ContextIndexSearcher searcher = shouldCollectSearch
+            ? newContextSearcher(reader, executor)
+            : newEarlyTerminationContextSearcher(reader, 0, executor);
         TestSearchContext context = new TestSearchContext(null, indexShard, searcher);
         context.parsedQuery(new ParsedQuery(query));
         context.setSize(0);
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
-        final boolean rescore = QueryPhase.executeInternal(context);
+        final boolean rescore = QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertFalse(rescore);
 
         ContextIndexSearcher countSearcher = shouldCollectCount
-            ? newContextSearcher(reader)
-            : newEarlyTerminationContextSearcher(reader, 0);
+            ? newContextSearcher(reader, executor)
+            : newEarlyTerminationContextSearcher(reader, 0, executor);
         assertEquals(countSearcher.count(query), context.queryResult().topDocs().topDocs.totalHits.value);
     }
 
@@ -157,7 +195,7 @@ private void countTestCase(boolean withDeletions) throws Exception {
         Directory dir = newDirectory();
         IndexWriterConfig iwc = newIndexWriterConfig().setMergePolicy(NoMergePolicy.INSTANCE);
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             Document doc = new Document();
             if (randomBoolean()) {
@@ -224,16 +262,16 @@ public void testPostFilterDisablesCountOptimization() throws Exception {
 
         IndexReader reader = DirectoryReader.open(dir);
 
-        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
 
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
 
-        context.setSearcher(newContextSearcher(reader));
+        context.setSearcher(newContextSearcher(reader, executor));
         context.parsedPostFilter(new ParsedQuery(new MatchNoDocsQuery()));
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
         reader.close();
         dir.close();
@@ -253,7 +291,7 @@ public void testTerminateAfterWithFilter() throws Exception {
 
         IndexReader reader = DirectoryReader.open(dir);
 
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
 
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
@@ -261,7 +299,7 @@ public void testTerminateAfterWithFilter() throws Exception {
         context.setSize(10);
         for (int i = 0; i < 10; i++) {
             context.parsedPostFilter(new ParsedQuery(new TermQuery(new Term("foo", Integer.toString(i)))));
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
         }
@@ -279,16 +317,17 @@ public void testMinScoreDisablesCountOptimization() throws Exception {
         w.close();
 
         IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
         context.setSize(0);
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
 
         context.minimumScore(100);
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertEquals(TotalHits.Relation.EQUAL_TO, context.queryResult().topDocs().topDocs.totalHits.relation);
         reader.close();
         dir.close();
     }
@@ -297,17 +336,17 @@ public void testQueryCapturesThreadPoolStats() throws Exception {
         Directory dir = newDirectory();
         IndexWriterConfig iwc = newIndexWriterConfig();
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             w.addDocument(new Document());
         }
         w.close();
         IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
 
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         QuerySearchResult results = context.queryResult();
         assertThat(results.serviceTimeEWMA(), greaterThanOrEqualTo(0L));
         assertThat(results.nodeQueueSize(), greaterThanOrEqualTo(0));
@@ -320,15 +359,16 @@ public void testInOrderScrollOptimization() throws Exception {
         final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
         IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             w.addDocument(new Document());
         }
         w.close();
         IndexReader reader = DirectoryReader.open(dir);
         ScrollContext scrollContext = new ScrollContext();
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader), scrollContext);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
         scrollContext.lastEmittedDoc = null;
         scrollContext.maxScore = Float.NaN;
         scrollContext.totalHits = null;
@@ -336,16 +376,15 @@ public void testInOrderScrollOptimization() throws Exception {
         int size = randomIntBetween(2, 5);
         context.setSize(size);
 
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
         assertNull(context.queryResult().terminatedEarly());
         assertThat(context.terminateAfter(), equalTo(0));
         assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
 
-        context.setSearcher(newEarlyTerminationContextSearcher(reader, size));
-        QueryPhase.executeInternal(context);
+        context.setSearcher(newEarlyTerminationContextSearcher(reader, size, executor));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
-        assertThat(context.terminateAfter(), equalTo(size));
         assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
         assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0].doc, greaterThanOrEqualTo(size));
         reader.close();
@@ -356,7 +395,7 @@ public void testTerminateAfterEarlyTermination() throws Exception {
         Directory dir = newDirectory();
         IndexWriterConfig iwc = newIndexWriterConfig();
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             Document doc = new Document();
             if (randomBoolean()) {
@@ -370,32 +409,35 @@ public void testTerminateAfterEarlyTermination() throws Exception {
         }
         w.close();
         final IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        if (this.executor != null) {
+            context.setConcurrentSegmentSearchEnabled(true);
+        }
 
         context.terminateAfter(numDocs);
         {
             context.setSize(10);
-            TotalHitCountCollector collector = new TotalHitCountCollector();
-            context.queryCollectors().put(TotalHitCountCollector.class, collector);
-            QueryPhase.executeInternal(context);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertFalse(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(10));
-            assertThat(collector.getTotalHits(), equalTo(numDocs));
+            assertThat(manager.getTotalHits(), equalTo(numDocs));
         }
 
         context.terminateAfter(1);
         {
             context.setSize(1);
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
 
             context.setSize(0);
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
@@ -403,7 +445,7 @@ public void testTerminateAfterEarlyTermination() throws Exception {
 
         {
             context.setSize(1);
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
@@ -414,38 +456,38 @@ public void testTerminateAfterEarlyTermination() throws Exception {
                 .add(new TermQuery(new Term("foo", "baz")), Occur.SHOULD)
                 .build();
             context.parsedQuery(new ParsedQuery(bq));
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
 
             context.setSize(0);
             context.parsedQuery(new ParsedQuery(bq));
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
         }
         {
             context.setSize(1);
-            TotalHitCountCollector collector = new TotalHitCountCollector();
-            context.queryCollectors().put(TotalHitCountCollector.class, collector);
-            QueryPhase.executeInternal(context);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, 1);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
-            assertThat(collector.getTotalHits(), equalTo(1));
-            context.queryCollectors().clear();
+            assertThat(manager.getTotalHits(), equalTo(1));
+            context.queryCollectorManagers().clear();
         }
         {
             context.setSize(0);
-            TotalHitCountCollector collector = new TotalHitCountCollector();
-            context.queryCollectors().put(TotalHitCountCollector.class, collector);
-            QueryPhase.executeInternal(context);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, 1);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
-            assertThat(collector.getTotalHits(), equalTo(1));
+            assertThat(manager.getTotalHits(), equalTo(1));
         }
 
         // tests with trackTotalHits and terminateAfter
@@ -453,9 +495,9 @@ public void testTerminateAfterEarlyTermination() throws Exception {
         context.setSize(0);
         for (int trackTotalHits : new int[] { -1, 3, 76, 100 }) {
             context.trackTotalHitsUpTo(trackTotalHits);
-            TotalHitCountCollector collector = new TotalHitCountCollector();
-            context.queryCollectors().put(TotalHitCountCollector.class, collector);
-            QueryPhase.executeInternal(context);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             if (trackTotalHits == -1) {
                 assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(0L));
@@ -463,16 +505,20 @@ public void testTerminateAfterEarlyTermination() throws Exception {
                 assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) Math.min(trackTotalHits, 10)));
             }
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
-            assertThat(collector.getTotalHits(), equalTo(10));
+            // The concurrent search terminates the collection when the number of hits is reached by each
+            // concurrent collector. In this case, in general, the number of results are multiplied by the number of
+            // slices (as the unit of concurrency). To address that, we have to use the shared global state,
+            // much as HitsThresholdChecker does.
+            if (executor == null) {
+                assertThat(manager.getTotalHits(), equalTo(10));
+            }
         }
 
         context.terminateAfter(7);
         context.setSize(10);
         for (int trackTotalHits : new int[] { -1, 3, 75, 100 }) {
             context.trackTotalHitsUpTo(trackTotalHits);
-            EarlyTerminatingCollector collector = new EarlyTerminatingCollector(new TotalHitCountCollector(), 1, false);
-            context.queryCollectors().put(EarlyTerminatingCollector.class, collector);
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertTrue(context.queryResult().terminatedEarly());
             if (trackTotalHits == -1) {
                 assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(0L));
@@ -490,7 +536,7 @@ public void testIndexSortingEarlyTermination() throws Exception {
         final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
         IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             Document doc = new Document();
             if (randomBoolean()) {
@@ -505,13 +551,13 @@ public void testIndexSortingEarlyTermination() throws Exception {
         w.close();
 
         final IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
         context.setSize(1);
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
         context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
 
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
         assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
         assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
@@ -520,7 +566,7 @@ public void testIndexSortingEarlyTermination() throws Exception {
 
         {
             context.parsedPostFilter(new ParsedQuery(new MinDocQuery(1)));
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(numDocs - 1L));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
@@ -528,28 +574,30 @@ public void testIndexSortingEarlyTermination() throws Exception {
             assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
             context.parsedPostFilter(null);
 
-            final TotalHitCountCollector totalHitCountCollector = new TotalHitCountCollector();
-            context.queryCollectors().put(TotalHitCountCollector.class, totalHitCountCollector);
-            QueryPhase.executeInternal(context);
+            final TestTotalHitCountCollectorManager manager = TestTotalHitCountCollectorManager.create(executor, sort);
+            context.queryCollectorManagers().put(TotalHitCountCollector.class, manager);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
             assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
-            assertThat(totalHitCountCollector.getTotalHits(), equalTo(numDocs));
-            context.queryCollectors().clear();
+            // When searching concurrently, each executors short-circuits when "size" is reached,
+            // including total hits collector
+            assertThat(manager.getTotalHits(), lessThanOrEqualTo(numDocs));
+            context.queryCollectorManagers().clear();
         }
 
         {
-            context.setSearcher(newEarlyTerminationContextSearcher(reader, 1));
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 1, executor));
             context.trackTotalHitsUpTo(SearchContext.TRACK_TOTAL_HITS_DISABLED);
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
             assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
 
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
             assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
@@ -564,7 +612,7 @@ public void testIndexSortScrollOptimization() throws Exception {
         final Sort indexSort = new Sort(new SortField("rank", SortField.Type.INT), new SortField("tiebreaker", SortField.Type.INT));
         IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(indexSort);
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
-        final int numDocs = scaledRandomIntBetween(100, 200);
+        final int numDocs = scaledRandomIntBetween(600, 900);
         for (int i = 0; i < numDocs; ++i) {
             Document doc = new Document();
             doc.add(new NumericDocValuesField("rank", random().nextInt()));
@@ -583,7 +631,7 @@ public void testIndexSortScrollOptimization() throws Exception {
         searchSortAndFormats.add(new SortAndFormats(new Sort(indexSort.getSort()[0]), new DocValueFormat[] { DocValueFormat.RAW }));
         for (SortAndFormats searchSortAndFormat : searchSortAndFormats) {
             ScrollContext scrollContext = new ScrollContext();
-            TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader), scrollContext);
+            TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
             context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
             scrollContext.lastEmittedDoc = null;
             scrollContext.maxScore = Float.NaN;
@@ -592,7 +640,7 @@ public void testIndexSortScrollOptimization() throws Exception {
             context.setSize(10);
             context.sort(searchSortAndFormat);
 
-            QueryPhase.executeInternal(context);
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.terminateAfter(), equalTo(0));
@@ -600,8 +648,8 @@ public void testIndexSortScrollOptimization() throws Exception {
             int sizeMinus1 = context.queryResult().topDocs().topDocs.scoreDocs.length - 1;
             FieldDoc lastDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[sizeMinus1];
 
-            context.setSearcher(newEarlyTerminationContextSearcher(reader, 10));
-            QueryPhase.executeInternal(context);
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 10, executor));
+            QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
             assertNull(context.queryResult().terminatedEarly());
             assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
             assertThat(context.terminateAfter(), equalTo(0));
@@ -630,7 +678,8 @@ public void testDisableTopScoreCollection() throws Exception {
         IndexWriterConfig iwc = newIndexWriterConfig(new StandardAnalyzer());
         RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
         Document doc = new Document();
-        for (int i = 0; i < 10; i++) {
+        final int numDocs = 2 * scaledRandomIntBetween(50, 450);
+        for (int i = 0; i < numDocs; i++) {
             doc.clear();
             if (i % 2 == 0) {
                 doc.add(new TextField("title", "foo bar", Store.NO));
@@ -642,7 +691,7 @@ public void testDisableTopScoreCollection() throws Exception {
         w.close();
 
         IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
         Query q = new SpanNearQuery.Builder("title", true).addClause(new SpanTermQuery(new Term("title", "foo")))
             .addClause(new SpanTermQuery(new Term("title", "bar")))
@@ -653,16 +702,16 @@ public void testDisableTopScoreCollection() throws Exception {
         context.trackTotalHitsUpTo(3);
         TopDocsCollectorContext topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
         assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.COMPLETE);
-        QueryPhase.executeInternal(context);
-        assertEquals(5, context.queryResult().topDocs().topDocs.totalHits.value);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
         assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.EQUAL_TO);
         assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
 
         context.sort(new SortAndFormats(new Sort(new SortField("other", SortField.Type.INT)), new DocValueFormat[] { DocValueFormat.RAW }));
         topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
         assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.TOP_DOCS);
-        QueryPhase.executeInternal(context);
-        assertEquals(5, context.queryResult().topDocs().topDocs.totalHits.value);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
         assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
         assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
 
@@ -718,79 +767,79 @@ public void testEnhanceSortOnNumeric() throws Exception {
 
         // 1. Test a sort on long field
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(longSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(10);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
             assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
         }
 
         // 2. Test a sort on long field + date field
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(longDateSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(10);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
             assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, true);
         }
 
         // 3. Test a sort on date field
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(dateSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(10);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
             assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
         }
 
         // 4. Test a sort on date field + long field
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(dateLongSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(10);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext, queryPhaseSearcher);
             assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, true);
         }
 
         // 5. Test that sort optimization is run when from > 0 and size = 0
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(longSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.from(5);
             searchContext.setSize(0);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
             assertSortResults(searchContext.queryResult().topDocs().topDocs, (long) numDocs, false);
         }
 
         // 6. Test that sort optimization works with from = 0 and size= 0
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             searchContext.sort(longSortAndFormats);
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(0);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext, queryPhaseSearcher);
         }
 
         // 7. Test that sort optimization works with search after
         {
-            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader)));
+            TestSearchContext searchContext = spy(new TestSearchContext(null, indexShard, newContextSearcher(reader, executor)));
             when(searchContext.mapperService()).thenReturn(mapperService);
             int afterDocument = (int) randomLongBetween(0, 50);
             long afterValue = firstValue + afterDocument;
@@ -800,11 +849,15 @@ public void testEnhanceSortOnNumeric() throws Exception {
             searchContext.parsedQuery(query);
             searchContext.setTask(task);
             searchContext.setSize(10);
-            QueryPhase.executeInternal(searchContext);
+            QueryPhase.executeInternal(searchContext.withCleanQueryResult(), queryPhaseSearcher);
             final TopDocs topDocs = searchContext.queryResult().topDocs().topDocs;
             long topValue = (long) ((FieldDoc) topDocs.scoreDocs[0]).fields[0];
             assertThat(topValue, greaterThan(afterValue));
             assertSortResults(topDocs, (long) numDocs, false);
+
+            final TotalHits totalHits = topDocs.totalHits;
+            assertEquals(TotalHits.Relation.EQUAL_TO, totalHits.relation);
+            assertEquals(numDocs, totalHits.value);
         }
 
         reader.close();
@@ -903,7 +956,7 @@ public void testMinScore() throws Exception {
         w.close();
 
         IndexReader reader = DirectoryReader.open(dir);
-        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader));
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
         context.parsedQuery(
             new ParsedQuery(
                 new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
@@ -916,13 +969,133 @@ public void testMinScore() throws Exception {
         context.setSize(1);
         context.trackTotalHitsUpTo(5);
 
-        QueryPhase.executeInternal(context);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
         assertEquals(10, context.queryResult().topDocs().topDocs.totalHits.value);
 
         reader.close();
         dir.close();
     }
 
+    public void testMaxScore() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("filter", SortField.Type.STRING));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new StringField("filter", "f1" + ((i > 0) ? " " + Integer.toString(i) : ""), Store.NO));
+            doc.add(new SortedDocValuesField("filter", newBytesRef("f1" + ((i > 0) ? " " + Integer.toString(i) : ""))));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.trackScores(true);
+        context.parsedQuery(
+            new ParsedQuery(
+                new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+                    .add(new TermQuery(new Term("filter", "f1")), Occur.SHOULD)
+                    .build()
+            )
+        );
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(1);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        context.trackScores(false);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertTrue(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testCollapseQuerySearchResults() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("user", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        // Always end up with uneven buckets so collapsing is predictable
+        final int numDocs = 2 * scaledRandomIntBetween(600, 900) - 1;
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new NumericDocValuesField("user", i & 1));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        when(queryShardContext.fieldMapper("user")).thenReturn(
+            new NumberFieldType("user", NumberType.INTEGER, true, false, true, false, null, Collections.emptyMap())
+        );
+
+        TestSearchContext context = new TestSearchContext(queryShardContext, indexShard, newContextSearcher(reader, executor));
+        context.collapse(new CollapseBuilder("user").build(context.getQueryShardContext()));
+        context.trackScores(true);
+        context.parsedQuery(new ParsedQuery(new TermQuery(new Term("foo", "bar"))));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(2);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        CollapseTopFieldDocs topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        context.trackScores(false);
+        QueryPhase.executeInternal(context.withCleanQueryResult(), queryPhaseSearcher);
+        assertTrue(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        topDocs = (CollapseTopFieldDocs) context.queryResult().topDocs().topDocs;
+        assertThat(topDocs.collapseValues.length, equalTo(2));
+        assertThat(topDocs.collapseValues[0], equalTo(0L)); // user == 0
+        assertThat(topDocs.collapseValues[1], equalTo(1L)); // user == 1
+
+        reader.close();
+        dir.close();
+    }
+
     public void testCancellationDuringPreprocess() throws IOException {
         try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir, newIndexWriterConfig())) {
 
@@ -939,9 +1112,12 @@ public void testCancellationDuringPreprocess() throws IOException {
             w.close();
 
             try (IndexReader reader = DirectoryReader.open(dir)) {
-                TestSearchContext context = new TestSearchContextWithRewriteAndCancellation(null, indexShard, newContextSearcher(reader));
-                PrefixQuery prefixQuery = new PrefixQuery(new Term("foo", "a"));
-                prefixQuery.setRewriteMethod(MultiTermQuery.SCORING_BOOLEAN_REWRITE);
+                TestSearchContext context = new TestSearchContextWithRewriteAndCancellation(
+                    null,
+                    indexShard,
+                    newContextSearcher(reader, executor)
+                );
+                PrefixQuery prefixQuery = new PrefixQuery(new Term("foo", "a"), MultiTermQuery.SCORING_BOOLEAN_REWRITE);
                 context.parsedQuery(new ParsedQuery(prefixQuery));
                 SearchShardTask task = mock(SearchShardTask.class);
                 when(task.isCancelled()).thenReturn(true);
@@ -951,6 +1127,58 @@ public void testCancellationDuringPreprocess() throws IOException {
         }
     }
 
+    public void testQueryTimeoutChecker() throws Exception {
+        long timeCacheLifespan = ThreadPool.ESTIMATED_TIME_INTERVAL_SETTING.get(Settings.EMPTY).millis();
+        long timeTolerance = timeCacheLifespan / 20;
+
+        // should throw time exceed exception for sure after timeCacheLifespan*2+timeTolerance (next's next cached time is available)
+        assertThrows(
+            QueryPhase.TimeExceededException.class,
+            () -> createTimeoutCheckerThenWaitThenRun(timeCacheLifespan, timeCacheLifespan * 2 + timeTolerance, true, false)
+        );
+
+        // should not throw time exceed exception after timeCacheLifespan+timeTolerance because new cached time - init time < timeout
+        createTimeoutCheckerThenWaitThenRun(timeCacheLifespan, timeCacheLifespan + timeTolerance, true, false);
+
+        // should not throw time exceed exception after timeout < timeCacheLifespan when cached time didn't change
+        createTimeoutCheckerThenWaitThenRun(timeCacheLifespan / 2, timeCacheLifespan / 2 + timeTolerance, false, true);
+        createTimeoutCheckerThenWaitThenRun(timeCacheLifespan / 4, timeCacheLifespan / 2 + timeTolerance, false, true);
+    }
+
+    private void createTimeoutCheckerThenWaitThenRun(
+        long timeout,
+        long sleepAfterCreation,
+        boolean checkCachedTimeChanged,
+        boolean checkCachedTimeHasNotChanged
+    ) throws Exception {
+        long timeCacheLifespan = ThreadPool.ESTIMATED_TIME_INTERVAL_SETTING.get(Settings.EMPTY).millis();
+        long timeTolerance = timeCacheLifespan / 20;
+        long currentTimeDiffWithCachedTime = TimeValue.nsecToMSec(System.nanoTime()) - threadPool.relativeTimeInMillis();
+        // need to run this test approximately at the start of cached time window
+        long timeToAlignTimeWithCachedTimeOffset = timeCacheLifespan - currentTimeDiffWithCachedTime + timeTolerance;
+        Thread.sleep(timeToAlignTimeWithCachedTimeOffset);
+
+        long initialRelativeCachedTime = threadPool.relativeTimeInMillis();
+        SearchContext mockedSearchContext = mock(SearchContext.class);
+        when(mockedSearchContext.timeout()).thenReturn(TimeValue.timeValueMillis(timeout));
+        when(mockedSearchContext.getRelativeTimeInMillis()).thenAnswer(invocation -> threadPool.relativeTimeInMillis());
+        when(mockedSearchContext.getRelativeTimeInMillis(eq(false))).thenCallRealMethod();
+        Runnable queryTimeoutChecker = QueryPhase.createQueryTimeoutChecker(mockedSearchContext);
+        // make sure next time slot become available
+        Thread.sleep(sleepAfterCreation);
+        if (checkCachedTimeChanged) {
+            assertNotEquals(initialRelativeCachedTime, threadPool.relativeTimeInMillis());
+        }
+        if (checkCachedTimeHasNotChanged) {
+            assertEquals(initialRelativeCachedTime, threadPool.relativeTimeInMillis());
+        }
+        queryTimeoutChecker.run();
+        verify(mockedSearchContext, times(1)).timeout();
+        verify(mockedSearchContext, times(1)).getRelativeTimeInMillis(eq(false));
+        verify(mockedSearchContext, atLeastOnce()).getRelativeTimeInMillis();
+        verifyNoMoreInteractions(mockedSearchContext);
+    }
+
     private static class TestSearchContextWithRewriteAndCancellation extends TestSearchContext {
 
         private TestSearchContextWithRewriteAndCancellation(
@@ -976,23 +1204,36 @@ public boolean lowLevelCancellation() {
         }
     }
 
-    private static ContextIndexSearcher newContextSearcher(IndexReader reader) throws IOException {
+    private static ContextIndexSearcher newContextSearcher(IndexReader reader, ExecutorService executor) throws IOException {
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
         return new ContextIndexSearcher(
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            executor,
+            searchContext
         );
     }
 
-    private static ContextIndexSearcher newEarlyTerminationContextSearcher(IndexReader reader, int size) throws IOException {
+    private static ContextIndexSearcher newEarlyTerminationContextSearcher(IndexReader reader, int size, ExecutorService executor)
+        throws IOException {
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
         return new ContextIndexSearcher(
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
             IndexSearcher.getDefaultQueryCachingPolicy(),
-            true
+            true,
+            executor,
+            searchContext
         ) {
 
             @Override
@@ -1003,6 +1244,66 @@ public void search(List<LeafReaderContext> leaves, Weight weight, Collector coll
         };
     }
 
+    private static class TestTotalHitCountCollectorManager extends TotalHitCountCollectorManager {
+        private int totalHits;
+        private final TotalHitCountCollector collector;
+        private final Integer teminateAfter;
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor) {
+            return create(executor, null, null);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Integer teminateAfter) {
+            return create(executor, null, teminateAfter);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Sort sort) {
+            return create(executor, sort, null);
+        }
+
+        static TestTotalHitCountCollectorManager create(final ExecutorService executor, final Sort sort, final Integer teminateAfter) {
+            if (executor == null) {
+                return new TestTotalHitCountCollectorManager(new TotalHitCountCollector(), sort);
+            } else {
+                return new TestTotalHitCountCollectorManager(sort, teminateAfter);
+            }
+        }
+
+        private TestTotalHitCountCollectorManager(final TotalHitCountCollector collector, final Sort sort) {
+            super(sort);
+            this.collector = collector;
+            this.teminateAfter = null;
+        }
+
+        private TestTotalHitCountCollectorManager(final Sort sort, final Integer teminateAfter) {
+            super(sort);
+            this.collector = null;
+            this.teminateAfter = teminateAfter;
+        }
+
+        @Override
+        public TotalHitCountCollector newCollector() throws IOException {
+            return (collector == null) ? super.newCollector() : collector;
+        }
+
+        @Override
+        public ReduceableSearchResult reduce(Collection<TotalHitCountCollector> collectors) throws IOException {
+            totalHits = collectors.stream().mapToInt(TotalHitCountCollector::getTotalHits).sum();
+
+            if (teminateAfter != null) {
+                assertThat(totalHits, greaterThanOrEqualTo(teminateAfter));
+                totalHits = Math.min(totalHits, teminateAfter);
+            }
+            // this collector should not participate in reduce as it is added for test purposes to capture the totalHits count
+            // returning a ReduceableSearchResult modifies the QueryResult which is not expected
+            return (result) -> {};
+        }
+
+        public int getTotalHits() {
+            return (collector == null) ? totalHits : collector.getTotalHits();
+        }
+    }
+
     private static class AssertingEarlyTerminationFilterCollector extends FilterCollector {
         private final int size;
 
diff --git a/server/src/test/java/org/opensearch/search/query/QueryProfilePhaseTests.java b/server/src/test/java/org/opensearch/search/query/QueryProfilePhaseTests.java
new file mode 100644
index 0000000000000..739ba6fc15c76
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/query/QueryProfilePhaseTests.java
@@ -0,0 +1,1490 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.query;
+
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field.Store;
+import org.apache.lucene.document.NumericDocValuesField;
+import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.TextField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.queries.spans.SpanNearQuery;
+import org.apache.lucene.queries.spans.SpanTermQuery;
+import org.apache.lucene.search.BooleanClause.Occur;
+import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.FieldComparator;
+import org.apache.lucene.search.FieldDoc;
+import org.apache.lucene.search.FilterCollector;
+import org.apache.lucene.search.FilterLeafCollector;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.LeafCollector;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.MatchNoDocsQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.search.TotalHits;
+import org.apache.lucene.search.Weight;
+import org.apache.lucene.search.grouping.CollapseTopFieldDocs;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.opensearch.index.mapper.NumberFieldMapper.NumberType;
+import org.opensearch.index.query.ParsedQuery;
+import org.opensearch.index.query.QueryShardContext;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.shard.IndexShardTestCase;
+import org.opensearch.lucene.queries.MinDocQuery;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.collapse.CollapseBuilder;
+import org.opensearch.search.internal.ContextIndexSearcher;
+import org.opensearch.search.internal.ScrollContext;
+import org.opensearch.search.internal.SearchContext;
+import org.opensearch.search.profile.ProfileResult;
+import org.opensearch.search.profile.ProfileShardResult;
+import org.opensearch.search.profile.SearchProfileShardResults;
+import org.opensearch.search.profile.query.CollectorResult;
+import org.opensearch.search.profile.query.QueryProfileShardResult;
+import org.opensearch.search.sort.SortAndFormats;
+import org.opensearch.test.TestSearchContext;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.Matchers.anyOf;
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class QueryProfilePhaseTests extends IndexShardTestCase {
+    private IndexShard indexShard;
+    private final ExecutorService executor;
+    private final QueryPhaseSearcher queryPhaseSearcher;
+
+    @ParametersFactory
+    public static Collection<Object[]> concurrency() {
+        return Arrays.asList(
+            new Object[] { 0, QueryPhase.DEFAULT_QUERY_PHASE_SEARCHER },
+            new Object[] { 5, new ConcurrentQueryPhaseSearcher() }
+        );
+    }
+
+    public QueryProfilePhaseTests(int concurrency, QueryPhaseSearcher queryPhaseSearcher) {
+        this.executor = (concurrency > 0) ? Executors.newFixedThreadPool(concurrency) : null;
+        this.queryPhaseSearcher = queryPhaseSearcher;
+    }
+
+    @Override
+    public Settings threadPoolSettings() {
+        return Settings.builder().put(super.threadPoolSettings()).put("thread_pool.search.min_queue_size", 10).build();
+    }
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        indexShard = newShard(true);
+    }
+
+    @Override
+    public void tearDown() throws Exception {
+        super.tearDown();
+        if (executor != null) {
+            ThreadPool.terminate(executor, 10, TimeUnit.SECONDS);
+        }
+        closeShards(indexShard);
+    }
+
+    public void testPostFilterDisablesCountOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+        // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+        // see: https://github.com/apache/lucene/pull/672
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_count"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.setSearcher(newContextSearcher(reader, executor));
+        context.parsedPostFilter(new ParsedQuery(new MatchNoDocsQuery()));
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertProfileData(context, collector -> {
+            assertThat(collector.getReason(), equalTo("search_post_filter"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), hasSize(1));
+            assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_count"));
+            assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+        }, (query) -> {
+            assertThat(query.getQueryName(), equalTo("MatchNoDocsQuery"));
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, (query) -> {
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertThat(query.getQueryName(), equalTo("ConstantScoreQuery"));
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testTerminateAfterWithFilter() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        for (int i = 0; i < 10; i++) {
+            doc.add(new StringField("foo", Integer.toString(i), Store.NO));
+        }
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.terminateAfter(1);
+        context.setSize(10);
+        for (int i = 0; i < 10; i++) {
+            context.parsedPostFilter(new ParsedQuery(new TermQuery(new Term("foo", Integer.toString(i)))));
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertProfileData(context, collector -> {
+                assertThat(collector.getReason(), equalTo("search_post_filter"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            }, (query) -> {
+                assertThat(query.getQueryName(), equalTo("TermQuery"));
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, (query) -> {
+                assertThat(query.getQueryName(), equalTo("MatchAllDocsQuery"));
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(1L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            });
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testMinScoreDisablesCountOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        w.addDocument(doc);
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newEarlyTerminationContextSearcher(reader, 0, executor));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.setSize(0);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(1, context.queryResult().topDocs().topDocs.totalHits.value);
+        // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+        // see: https://github.com/apache/lucene/pull/672
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_count"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.minimumScore(100);
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(0, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertEquals(TotalHits.Relation.EQUAL_TO, context.queryResult().topDocs().topDocs.totalHits.relation);
+        assertProfileData(context, "MatchAllDocsQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThanOrEqualTo(100L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(1L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_min_score"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), hasSize(1));
+            assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_count"));
+            assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testInOrderScrollOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            w.addDocument(new Document());
+        }
+        w.close();
+        IndexReader reader = DirectoryReader.open(dir);
+        ScrollContext scrollContext = new ScrollContext();
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        scrollContext.lastEmittedDoc = null;
+        scrollContext.maxScore = Float.NaN;
+        scrollContext.totalHits = null;
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        int size = randomIntBetween(2, 5);
+        context.setSize(size);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertNull(context.queryResult().terminatedEarly());
+        assertThat(context.terminateAfter(), equalTo(0));
+        assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.setSearcher(newEarlyTerminationContextSearcher(reader, size, executor));
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0].doc, greaterThanOrEqualTo(size));
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), hasSize(0));
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testTerminateAfterEarlyTermination() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "bar", Store.NO));
+            }
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "baz", Store.NO));
+            }
+            doc.add(new NumericDocValuesField("rank", numDocs - i));
+            w.addDocument(doc);
+        }
+        w.close();
+        final IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+
+        context.terminateAfter(1);
+        {
+            context.setSize(1);
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertProfileData(context, "MatchAllDocsQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+
+            context.setSize(0);
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_count"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+        }
+
+        {
+            context.setSize(1);
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertProfileData(context, "MatchAllDocsQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+        }
+        {
+            context.setSize(1);
+            BooleanQuery bq = new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.SHOULD)
+                .add(new TermQuery(new Term("foo", "baz")), Occur.SHOULD)
+                .build();
+            context.parsedQuery(new ParsedQuery(bq));
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertProfileData(context, "BooleanQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+                assertThat(query.getProfiledChildren(), hasSize(2));
+                assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("TermQuery"));
+                assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+                assertThat(query.getProfiledChildren().get(1).getQueryName(), equalTo("TermQuery"));
+                assertThat(query.getProfiledChildren().get(1).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+            context.setSize(0);
+            context.parsedQuery(new ParsedQuery(bq));
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(0));
+
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+                // rewritten as a ConstantScoreQuery wrapping the original BooleanQuery
+                // see: https://github.com/apache/lucene/pull/672
+                assertThat(query.getProfiledChildren(), hasSize(1));
+                assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("BooleanQuery"));
+                assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score_count"), equalTo(0L));
+
+                List<ProfileResult> children = query.getProfiledChildren().get(0).getProfiledChildren();
+                assertThat(children, hasSize(2));
+                assertThat(children.get(0).getQueryName(), equalTo("TermQuery"));
+                assertThat(children.get(0).getTime(), greaterThan(0L));
+                assertThat(children.get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(children.get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+                assertThat(children.get(0).getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(children.get(0).getTimeBreakdown().get("score_count"), equalTo(0L));
+
+                assertThat(children.get(1).getQueryName(), equalTo("TermQuery"));
+                assertThat(children.get(1).getTime(), greaterThan(0L));
+                assertThat(children.get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(children.get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+                assertThat(children.get(1).getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(children.get(1).getTimeBreakdown().get("score_count"), equalTo(0L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_count"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+        }
+
+        context.terminateAfter(7);
+        context.setSize(10);
+        for (int trackTotalHits : new int[] { -1, 3, 75, 100 }) {
+            context.trackTotalHitsUpTo(trackTotalHits);
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertTrue(context.queryResult().terminatedEarly());
+            if (trackTotalHits == -1) {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(0L));
+            } else {
+                assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(7L));
+            }
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(7));
+            assertProfileData(context, "BooleanQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), greaterThanOrEqualTo(7L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+                assertThat(query.getProfiledChildren(), hasSize(2));
+                assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("TermQuery"));
+                assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score_count"), greaterThan(0L));
+
+                assertThat(query.getProfiledChildren().get(1).getQueryName(), equalTo("TermQuery"));
+                assertThat(query.getProfiledChildren().get(1).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("score"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("score_count"), greaterThan(0L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_terminate_after_count"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            });
+        }
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testIndexSortingEarlyTermination() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("rank", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "bar", Store.NO));
+            }
+            if (randomBoolean()) {
+                doc.add(new StringField("foo", "baz", Store.NO));
+            }
+            doc.add(new NumericDocValuesField("rank", numDocs - i));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        final IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+        context.setSize(1);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+        FieldDoc fieldDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[0];
+        assertThat(fieldDoc.fields[0], equalTo(1));
+        // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+        // see: https://github.com/apache/lucene/pull/672
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        {
+            context.parsedPostFilter(new ParsedQuery(new MinDocQuery(1)));
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo(numDocs - 1L));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+            assertProfileData(context, collector -> {
+                assertThat(collector.getReason(), equalTo("search_post_filter"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), hasSize(1));
+                assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+            }, (query) -> {
+                assertThat(query.getQueryName(), equalTo("MinDocQuery"));
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, (query) -> {
+                // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+                // see: https://github.com/apache/lucene/pull/672
+                assertThat(query.getQueryName(), equalTo("ConstantScoreQuery"));
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            });
+            context.parsedPostFilter(null);
+        }
+
+        {
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 1, executor));
+            context.trackTotalHitsUpTo(SearchContext.TRACK_TOTAL_HITS_DISABLED);
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), empty());
+            });
+
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(1));
+            assertThat(context.queryResult().topDocs().topDocs.scoreDocs[0], instanceOf(FieldDoc.class));
+            assertThat(fieldDoc.fields[0], anyOf(equalTo(1), equalTo(2)));
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), empty());
+            });
+        }
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testIndexSortScrollOptimization() throws Exception {
+        Directory dir = newDirectory();
+        final Sort indexSort = new Sort(new SortField("rank", SortField.Type.INT), new SortField("tiebreaker", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(indexSort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; ++i) {
+            Document doc = new Document();
+            doc.add(new NumericDocValuesField("rank", random().nextInt()));
+            doc.add(new NumericDocValuesField("tiebreaker", i));
+            w.addDocument(doc);
+        }
+        if (randomBoolean()) {
+            w.forceMerge(randomIntBetween(1, 10));
+        }
+        w.close();
+
+        final IndexReader reader = DirectoryReader.open(dir);
+        List<SortAndFormats> searchSortAndFormats = new ArrayList<>();
+        searchSortAndFormats.add(new SortAndFormats(indexSort, new DocValueFormat[] { DocValueFormat.RAW, DocValueFormat.RAW }));
+        // search sort is a prefix of the index sort
+        searchSortAndFormats.add(new SortAndFormats(new Sort(indexSort.getSort()[0]), new DocValueFormat[] { DocValueFormat.RAW }));
+        for (SortAndFormats searchSortAndFormat : searchSortAndFormats) {
+            ScrollContext scrollContext = new ScrollContext();
+            TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor), scrollContext);
+            context.parsedQuery(new ParsedQuery(new MatchAllDocsQuery()));
+            scrollContext.lastEmittedDoc = null;
+            scrollContext.maxScore = Float.NaN;
+            scrollContext.totalHits = null;
+            context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+            context.setSize(10);
+            context.sort(searchSortAndFormat);
+
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.terminateAfter(), equalTo(0));
+            assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+            // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+            // see: https://github.com/apache/lucene/pull/672
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), empty());
+            });
+
+            int sizeMinus1 = context.queryResult().topDocs().topDocs.scoreDocs.length - 1;
+            FieldDoc lastDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[sizeMinus1];
+
+            context.setSearcher(newEarlyTerminationContextSearcher(reader, 10, executor));
+            QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+            assertNull(context.queryResult().terminatedEarly());
+            assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+            assertThat(context.terminateAfter(), equalTo(0));
+            assertThat(context.queryResult().getTotalHits().value, equalTo((long) numDocs));
+            assertProfileData(context, "ConstantScoreQuery", query -> {
+                assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+                assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+                assertThat(query.getProfiledChildren(), hasSize(1));
+                assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("SearchAfterSortedDocQuery"));
+                assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score"), equalTo(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("score_count"), equalTo(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+                assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            }, collector -> {
+                assertThat(collector.getReason(), equalTo("search_top_hits"));
+                assertThat(collector.getTime(), greaterThan(0L));
+                if (collector.getName().contains("CollectorManager")) {
+                    assertThat(collector.getReduceTime(), greaterThan(0L));
+                }
+                assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+                assertThat(collector.getMinSliceTime(), greaterThan(0L));
+                assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+                assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+                assertThat(collector.getProfiledChildren(), empty());
+            });
+            FieldDoc firstDoc = (FieldDoc) context.queryResult().topDocs().topDocs.scoreDocs[0];
+            for (int i = 0; i < searchSortAndFormat.sort.getSort().length; i++) {
+                @SuppressWarnings("unchecked")
+                FieldComparator<Object> comparator = (FieldComparator<Object>) searchSortAndFormat.sort.getSort()[i].getComparator(
+                    i,
+                    randomBoolean()
+                );
+                int cmp = comparator.compareValues(firstDoc.fields[i], lastDoc.fields[i]);
+                if (cmp == 0) {
+                    continue;
+                }
+                assertThat(cmp, equalTo(1));
+                break;
+            }
+        }
+        reader.close();
+        dir.close();
+    }
+
+    public void testDisableTopScoreCollection() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig(new StandardAnalyzer());
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        Document doc = new Document();
+        final int numDocs = 2 * scaledRandomIntBetween(50, 450);
+        for (int i = 0; i < numDocs; i++) {
+            doc.clear();
+            if (i % 2 == 0) {
+                doc.add(new TextField("title", "foo bar", Store.NO));
+            } else {
+                doc.add(new TextField("title", "foo", Store.NO));
+            }
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        Query q = new SpanNearQuery.Builder("title", true).addClause(new SpanTermQuery(new Term("title", "foo")))
+            .addClause(new SpanTermQuery(new Term("title", "bar")))
+            .build();
+
+        context.parsedQuery(new ParsedQuery(q));
+        context.setSize(3);
+        context.trackTotalHitsUpTo(3);
+        TopDocsCollectorContext topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
+        assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.COMPLETE);
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.EQUAL_TO);
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
+        assertProfileData(context, "SpanNearQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.sort(new SortAndFormats(new Sort(new SortField("other", SortField.Type.INT)), new DocValueFormat[] { DocValueFormat.RAW }));
+        topDocsContext = TopDocsCollectorContext.createTopDocsCollectorContext(context, false);
+        assertEquals(topDocsContext.create(null).scoreMode(), org.apache.lucene.search.ScoreMode.TOP_DOCS);
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(numDocs / 2, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertThat(context.queryResult().topDocs().topDocs.scoreDocs.length, equalTo(3));
+        assertEquals(context.queryResult().topDocs().topDocs.totalHits.relation, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+        // IndexSearcher#rewrite optimizes by rewriting non-scoring queries to ConstantScoreQuery
+        // see: https://github.com/apache/lucene/pull/672
+        assertProfileData(context, "ConstantScoreQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testMinScore() throws Exception {
+        Directory dir = newDirectory();
+        IndexWriterConfig iwc = newIndexWriterConfig();
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+        for (int i = 0; i < 10; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new StringField("filter", "f1", Store.NO));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.parsedQuery(
+            new ParsedQuery(
+                new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+                    .add(new TermQuery(new Term("filter", "f1")), Occur.SHOULD)
+                    .build()
+            )
+        );
+        context.minimumScore(0.01f);
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(1);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertEquals(10, context.queryResult().topDocs().topDocs.totalHits.value);
+        assertProfileData(context, "BooleanQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), equalTo(10L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren(), hasSize(2));
+            assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren().get(1).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(1).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_min_score"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), hasSize(1));
+            assertThat(collector.getProfiledChildren().get(0).getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getProfiledChildren().get(0).getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getProfiledChildren().get(0).getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getProfiledChildren().get(0).getSliceCount(), greaterThanOrEqualTo(1));
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testMaxScore() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("filter", SortField.Type.STRING));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        final int numDocs = scaledRandomIntBetween(600, 900);
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new StringField("filter", "f1" + ((i > 0) ? " " + Integer.toString(i) : ""), Store.NO));
+            doc.add(new SortedDocValuesField("filter", newBytesRef("f1" + ((i > 0) ? " " + Integer.toString(i) : ""))));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        TestSearchContext context = new TestSearchContext(null, indexShard, newContextSearcher(reader, executor));
+        context.trackScores(true);
+        context.parsedQuery(
+            new ParsedQuery(
+                new BooleanQuery.Builder().add(new TermQuery(new Term("foo", "bar")), Occur.MUST)
+                    .add(new TermQuery(new Term("filter", "f1")), Occur.SHOULD)
+                    .build()
+            )
+        );
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(1);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+        assertProfileData(context, "BooleanQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), greaterThanOrEqualTo(6L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren(), hasSize(2));
+            assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren().get(1).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(1).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(1, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, greaterThanOrEqualTo(6L));
+        assertProfileData(context, "BooleanQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), greaterThanOrEqualTo(6L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren(), hasSize(2));
+            assertThat(query.getProfiledChildren().get(0).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(0).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(0).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+
+            assertThat(query.getProfiledChildren().get(1).getQueryName(), equalTo("TermQuery"));
+            assertThat(query.getProfiledChildren().get(1).getTime(), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getProfiledChildren().get(1).getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    public void testCollapseQuerySearchResults() throws Exception {
+        Directory dir = newDirectory();
+        final Sort sort = new Sort(new SortField("user", SortField.Type.INT));
+        IndexWriterConfig iwc = newIndexWriterConfig().setIndexSort(sort);
+        RandomIndexWriter w = new RandomIndexWriter(random(), dir, iwc);
+
+        // Always end up with uneven buckets so collapsing is predictable
+        final int numDocs = 2 * scaledRandomIntBetween(600, 900) - 1;
+        for (int i = 0; i < numDocs; i++) {
+            Document doc = new Document();
+            doc.add(new StringField("foo", "bar", Store.NO));
+            doc.add(new NumericDocValuesField("user", i & 1));
+            w.addDocument(doc);
+        }
+        w.close();
+
+        IndexReader reader = DirectoryReader.open(dir);
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        when(queryShardContext.fieldMapper("user")).thenReturn(
+            new NumberFieldType("user", NumberType.INTEGER, true, false, true, false, null, Collections.emptyMap())
+        );
+
+        TestSearchContext context = new TestSearchContext(queryShardContext, indexShard, newContextSearcher(reader, executor));
+        context.collapse(new CollapseBuilder("user").build(context.getQueryShardContext()));
+        context.trackScores(true);
+        context.parsedQuery(new ParsedQuery(new TermQuery(new Term("foo", "bar"))));
+        context.setTask(new SearchShardTask(123L, "", "", "", null, Collections.emptyMap()));
+        context.setSize(2);
+        context.trackTotalHitsUpTo(5);
+
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        assertProfileData(context, "TermQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), greaterThanOrEqualTo(6L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            assertThat(query.getProfiledChildren(), empty());
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        context.sort(new SortAndFormats(sort, new DocValueFormat[] { DocValueFormat.RAW }));
+        QueryPhase.executeInternal(context.withCleanQueryResult().withProfilers(), queryPhaseSearcher);
+        assertFalse(Float.isNaN(context.queryResult().getMaxScore()));
+        assertEquals(2, context.queryResult().topDocs().topDocs.scoreDocs.length);
+        assertThat(context.queryResult().topDocs().topDocs.totalHits.value, equalTo((long) numDocs));
+        assertThat(context.queryResult().topDocs().topDocs, instanceOf(CollapseTopFieldDocs.class));
+
+        assertProfileData(context, "TermQuery", query -> {
+            assertThat(query.getTimeBreakdown().keySet(), not(empty()));
+            assertThat(query.getTimeBreakdown().get("score"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("score_count"), greaterThanOrEqualTo(6L));
+            assertThat(query.getTimeBreakdown().get("create_weight"), greaterThan(0L));
+            assertThat(query.getTimeBreakdown().get("create_weight_count"), equalTo(1L));
+            assertThat(query.getProfiledChildren(), empty());
+        }, collector -> {
+            assertThat(collector.getReason(), equalTo("search_top_hits"));
+            assertThat(collector.getTime(), greaterThan(0L));
+            if (collector.getName().contains("CollectorManager")) {
+                assertThat(collector.getReduceTime(), greaterThan(0L));
+            }
+            assertThat(collector.getMaxSliceTime(), greaterThan(0L));
+            assertThat(collector.getMinSliceTime(), greaterThan(0L));
+            assertThat(collector.getAvgSliceTime(), greaterThan(0L));
+            assertThat(collector.getSliceCount(), greaterThanOrEqualTo(1));
+            assertThat(collector.getProfiledChildren(), empty());
+        });
+
+        reader.close();
+        dir.close();
+    }
+
+    private void assertProfileData(SearchContext context, String type, Consumer<ProfileResult> query, Consumer<CollectorResult> collector)
+        throws IOException {
+        assertProfileData(context, collector, (profileResult) -> {
+            assertThat(profileResult.getQueryName(), equalTo(type));
+            assertThat(profileResult.getTime(), greaterThan(0L));
+            query.accept(profileResult);
+        });
+    }
+
+    private void assertProfileData(SearchContext context, Consumer<CollectorResult> collector, Consumer<ProfileResult> query1)
+        throws IOException {
+        assertProfileData(context, Arrays.asList(query1), collector, false);
+    }
+
+    private void assertProfileData(
+        SearchContext context,
+        Consumer<CollectorResult> collector,
+        Consumer<ProfileResult> query1,
+        Consumer<ProfileResult> query2
+    ) throws IOException {
+        assertProfileData(context, Arrays.asList(query1, query2), collector, false);
+    }
+
+    private final void assertProfileData(
+        SearchContext context,
+        List<Consumer<ProfileResult>> queries,
+        Consumer<CollectorResult> collector,
+        boolean debug
+    ) throws IOException {
+        assertThat(context.getProfilers(), not(nullValue()));
+
+        final ProfileShardResult result = SearchProfileShardResults.buildShardResults(context.getProfilers(), null);
+        if (debug) {
+            final SearchProfileShardResults results = new SearchProfileShardResults(
+                Collections.singletonMap(indexShard.shardId().toString(), result)
+            );
+
+            try (final XContentBuilder builder = JsonXContent.contentBuilder().prettyPrint()) {
+                builder.startObject();
+                results.toXContent(builder, ToXContent.EMPTY_PARAMS);
+                builder.endObject();
+                builder.flush();
+
+                final OutputStream out = builder.getOutputStream();
+                assertThat(out, instanceOf(ByteArrayOutputStream.class));
+
+                logger.info(new String(((ByteArrayOutputStream) out).toByteArray(), StandardCharsets.UTF_8));
+            }
+        }
+
+        assertThat(result.getQueryProfileResults(), hasSize(1));
+
+        final QueryProfileShardResult queryProfileShardResult = result.getQueryProfileResults().get(0);
+        assertThat(queryProfileShardResult.getQueryResults(), hasSize(queries.size()));
+
+        for (int i = 0; i < queries.size(); ++i) {
+            queries.get(i).accept(queryProfileShardResult.getQueryResults().get(i));
+        }
+
+        collector.accept(queryProfileShardResult.getCollectorResult());
+    }
+
+    private static ContextIndexSearcher newContextSearcher(IndexReader reader, ExecutorService executor) throws IOException {
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
+        return new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            executor,
+            searchContext
+        );
+    }
+
+    private static ContextIndexSearcher newEarlyTerminationContextSearcher(IndexReader reader, int size, ExecutorService executor)
+        throws IOException {
+        SearchContext searchContext = mock(SearchContext.class);
+        IndexShard indexShard = mock(IndexShard.class);
+        when(searchContext.indexShard()).thenReturn(indexShard);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(SearchContext.NO_OP_BUCKET_COLLECTOR_PROCESSOR);
+        return new ContextIndexSearcher(
+            reader,
+            IndexSearcher.getDefaultSimilarity(),
+            IndexSearcher.getDefaultQueryCache(),
+            IndexSearcher.getDefaultQueryCachingPolicy(),
+            true,
+            executor,
+            searchContext
+        ) {
+
+            @Override
+            public void search(List<LeafReaderContext> leaves, Weight weight, Collector collector) throws IOException {
+                final Collector in = new AssertingEarlyTerminationFilterCollector(collector, size);
+                super.search(leaves, weight, in);
+            }
+        };
+    }
+
+    private static class AssertingEarlyTerminationFilterCollector extends FilterCollector {
+        private final int size;
+
+        AssertingEarlyTerminationFilterCollector(Collector in, int size) {
+            super(in);
+            this.size = size;
+        }
+
+        @Override
+        public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
+            final LeafCollector in = super.getLeafCollector(context);
+            return new FilterLeafCollector(in) {
+                int collected;
+
+                @Override
+                public void collect(int doc) throws IOException {
+                    assert collected <= size : "should not collect more than " + size + " doc per segment, got " + collected;
+                    ++collected;
+                    super.collect(doc);
+                }
+            };
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/query/QuerySearchResultTests.java b/server/src/test/java/org/opensearch/search/query/QuerySearchResultTests.java
index 6b89eb92065b1..0a03a9bbdb40b 100644
--- a/server/src/test/java/org/opensearch/search/query/QuerySearchResultTests.java
+++ b/server/src/test/java/org/opensearch/search/query/QuerySearchResultTests.java
@@ -40,14 +40,14 @@
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.OriginalIndicesTests;
 import org.opensearch.action.search.SearchRequest;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchShardTarget;
diff --git a/server/src/test/java/org/opensearch/search/query/ScriptScoreQueryTests.java b/server/src/test/java/org/opensearch/search/query/ScriptScoreQueryTests.java
index e1002e114822e..ca4b7dc49f6f0 100644
--- a/server/src/test/java/org/opensearch/search/query/ScriptScoreQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/query/ScriptScoreQueryTests.java
@@ -184,6 +184,7 @@ private ScoreScript.LeafFactory newFactory(
     ) {
         SearchLookup lookup = mock(SearchLookup.class);
         LeafSearchLookup leafLookup = mock(LeafSearchLookup.class);
+        IndexSearcher indexSearcher = mock(IndexSearcher.class);
         when(lookup.getLeafSearchLookup(any())).thenReturn(leafLookup);
         return new ScoreScript.LeafFactory() {
             @Override
@@ -193,7 +194,7 @@ public boolean needs_score() {
 
             @Override
             public ScoreScript newInstance(LeafReaderContext ctx) throws IOException {
-                return new ScoreScript(script.getParams(), lookup, leafReaderContext) {
+                return new ScoreScript(script.getParams(), lookup, indexSearcher, leafReaderContext) {
                     @Override
                     public double execute(ExplanationHolder explanation) {
                         return function.apply(explanation);
diff --git a/server/src/test/java/org/opensearch/search/rescore/QueryRescorerBuilderTests.java b/server/src/test/java/org/opensearch/search/rescore/QueryRescorerBuilderTests.java
index b96fa3be99895..a71c18aa2266b 100644
--- a/server/src/test/java/org/opensearch/search/rescore/QueryRescorerBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/rescore/QueryRescorerBuilderTests.java
@@ -36,19 +36,19 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.mapper.ContentPath;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -61,8 +61,8 @@
 import org.opensearch.index.query.Rewriteable;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.rescore.QueryRescorer.QueryRescoreContext;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
@@ -130,7 +130,7 @@ private RescorerBuilder<?> copy(RescorerBuilder<?> original) throws IOException
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             RescorerBuilder<?> rescoreBuilder = randomRescoreBuilder();
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 builder.prettyPrint();
             }
diff --git a/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java b/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
index 065635eff672d..748bbb81b0513 100644
--- a/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
+++ b/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.scroll;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollResponse;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.search.RestClearScrollAction;
 import org.opensearch.test.OpenSearchTestCase;
@@ -57,7 +57,7 @@ public void testParseClearScrollRequestWithInvalidJsonThrowsException() throws E
         RestClearScrollAction action = new RestClearScrollAction();
         RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray("{invalid_json}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         Exception e = expectThrows(IllegalArgumentException.class, () -> action.prepareRequest(request, null));
         assertThat(e.getMessage(), equalTo("Failed to parse request body"));
@@ -76,7 +76,7 @@ public void clearScroll(ClearScrollRequest request, ActionListener<ClearScrollRe
             RestClearScrollAction action = new RestClearScrollAction();
             RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(
                 Collections.singletonMap("scroll_id", "QUERY_STRING")
-            ).withContent(new BytesArray("{\"scroll_id\": [\"BODY\"]}"), XContentType.JSON).build();
+            ).withContent(new BytesArray("{\"scroll_id\": [\"BODY\"]}"), MediaTypeRegistry.JSON).build();
             FakeRestChannel channel = new FakeRestChannel(request, false, 0);
             action.handleRequest(request, channel, nodeClient);
 
diff --git a/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java b/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
index 9e5c74be47525..3c73e6a865409 100644
--- a/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
+++ b/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.search.scroll;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.search.RestSearchScrollAction;
 import org.opensearch.test.OpenSearchTestCase;
@@ -57,7 +57,7 @@ public void testParseSearchScrollRequestWithInvalidJsonThrowsException() throws
         RestSearchScrollAction action = new RestSearchScrollAction();
         RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(
             new BytesArray("{invalid_json}"),
-            XContentType.JSON
+            MediaTypeRegistry.JSON
         ).build();
         Exception e = expectThrows(IllegalArgumentException.class, () -> action.prepareRequest(request, null));
         assertThat(e.getMessage(), equalTo("Failed to parse request body"));
@@ -78,7 +78,7 @@ public void searchScroll(SearchScrollRequest request, ActionListener<SearchRespo
             params.put("scroll_id", "QUERY_STRING");
             params.put("scroll", "1000m");
             RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withParams(params)
-                .withContent(new BytesArray("{\"scroll_id\":\"BODY\", \"scroll\":\"1m\"}"), XContentType.JSON)
+                .withContent(new BytesArray("{\"scroll_id\":\"BODY\", \"scroll\":\"1m\"}"), MediaTypeRegistry.JSON)
                 .build();
             FakeRestChannel channel = new FakeRestChannel(request, false, 0);
             action.handleRequest(request, channel, nodeClient);
diff --git a/server/src/test/java/org/opensearch/search/searchafter/SearchAfterBuilderTests.java b/server/src/test/java/org/opensearch/search/searchafter/SearchAfterBuilderTests.java
index 6d2817269c838..cc5c205f7f9fe 100644
--- a/server/src/test/java/org/opensearch/search/searchafter/SearchAfterBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/searchafter/SearchAfterBuilderTests.java
@@ -37,16 +37,17 @@
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedNumericSortField;
 import org.apache.lucene.search.SortedSetSortField;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.MultiValueMode;
@@ -190,7 +191,7 @@ public void testEqualsAndHashcode() throws Exception {
     public void testFromXContent() throws Exception {
         for (int runs = 0; runs < 20; runs++) {
             SearchAfterBuilder searchAfterBuilder = randomJsonSearchFromBuilder();
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 builder.prettyPrint();
             }
@@ -213,10 +214,10 @@ public void testFromXContentIllegalType() throws Exception {
         for (XContentType type : XContentType.values()) {
             // BIG_DECIMAL
             // ignore json and yaml, they parse floating point numbers as floats/doubles
-            if (type == XContentType.JSON || type == XContentType.YAML) {
+            if (type == MediaTypeRegistry.JSON || type == XContentType.YAML) {
                 continue;
             }
-            XContentBuilder xContent = XContentFactory.contentBuilder(type);
+            XContentBuilder xContent = MediaTypeRegistry.contentBuilder(type);
             xContent.startObject().startArray("search_after").value(new BigDecimal("9223372036854776003.3")).endArray().endObject();
             try (XContentParser parser = createParser(xContent)) {
                 parser.nextToken();
diff --git a/server/src/test/java/org/opensearch/search/slice/DocValuesSliceQueryTests.java b/server/src/test/java/org/opensearch/search/slice/DocValuesSliceQueryTests.java
index 2bf1225aa9b11..70c5e0a4a8237 100644
--- a/server/src/test/java/org/opensearch/search/slice/DocValuesSliceQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/slice/DocValuesSliceQueryTests.java
@@ -32,23 +32,23 @@
 
 package org.opensearch.search.slice;
 
-import com.carrotsearch.hppc.BitMixer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.LeafCollector;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.common.UUIDs;
+import org.opensearch.common.util.BitMixer;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -110,7 +110,7 @@ public void setScorer(Scorable scorer) throws IOException {}
 
                         @Override
                         public void collect(int doc) throws IOException {
-                            Document d = context.reader().document(doc, Collections.singleton("uuid"));
+                            Document d = context.reader().storedFields().document(doc, Collections.singleton("uuid"));
                             String uuid = d.get("uuid");
                             assertThat(keys.contains(uuid), equalTo(true));
                             keys.remove(uuid);
diff --git a/server/src/test/java/org/opensearch/search/slice/SliceBuilderTests.java b/server/src/test/java/org/opensearch/search/slice/SliceBuilderTests.java
index a7cf4ef6c0a2b..2761efc00f4fe 100644
--- a/server/src/test/java/org/opensearch/search/slice/SliceBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/slice/SliceBuilderTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.search.slice;
 
-import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexReader;
@@ -42,6 +41,7 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.opensearch.Version;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.search.SearchRequest;
@@ -54,20 +54,20 @@
 import org.opensearch.cluster.routing.ShardIterator;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.fielddata.IndexNumericFieldData;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.TextSearchInfo;
 import org.opensearch.index.mapper.ValueFetcher;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.lookup.SearchLookup;
 import org.opensearch.test.OpenSearchTestCase;
@@ -208,7 +208,7 @@ public void testEqualsAndHashcode() throws Exception {
 
     public void testFromXContent() throws Exception {
         SliceBuilder sliceBuilder = randomSliceBuilder();
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
diff --git a/server/src/test/java/org/opensearch/search/slice/TermsSliceQueryTests.java b/server/src/test/java/org/opensearch/search/slice/TermsSliceQueryTests.java
index 84a65b3c8a7cb..c7fb94edd9af0 100644
--- a/server/src/test/java/org/opensearch/search/slice/TermsSliceQueryTests.java
+++ b/server/src/test/java/org/opensearch/search/slice/TermsSliceQueryTests.java
@@ -38,14 +38,14 @@
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.LeafCollector;
-import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.search.Scorable;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.QueryUtils;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.StringHelper;
 import org.opensearch.common.UUIDs;
@@ -120,7 +120,7 @@ public void setScorer(Scorable scorer) throws IOException {}
 
                         @Override
                         public void collect(int doc) throws IOException {
-                            Document d = context.reader().document(doc, Collections.singleton("uuid"));
+                            Document d = context.reader().storedFields().document(doc, Collections.singleton("uuid"));
                             String uuid = d.get("uuid");
                             assertThat(keys.contains(uuid), equalTo(true));
                             keys.remove(uuid);
diff --git a/server/src/test/java/org/opensearch/search/sort/AbstractSortTestCase.java b/server/src/test/java/org/opensearch/search/sort/AbstractSortTestCase.java
index 4225f46a41a6d..257ff1015e3b4 100644
--- a/server/src/test/java/org/opensearch/search/sort/AbstractSortTestCase.java
+++ b/server/src/test/java/org/opensearch/search/sort/AbstractSortTestCase.java
@@ -37,17 +37,17 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
 import org.opensearch.index.fielddata.IndexFieldData;
@@ -71,11 +71,10 @@
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.lookup.SearchLookup;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.mockito.Mockito;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -83,6 +82,8 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyList;
 import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
 
@@ -131,7 +132,7 @@ public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             T testItem = createTestItem();
 
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 builder.prettyPrint();
             }
diff --git a/server/src/test/java/org/opensearch/search/sort/BucketedSortForIntsTests.java b/server/src/test/java/org/opensearch/search/sort/BucketedSortForIntsTests.java
new file mode 100644
index 0000000000000..c3e0475685001
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/sort/BucketedSortForIntsTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.sort;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.opensearch.search.DocValueFormat;
+
+public class BucketedSortForIntsTests extends BucketedSortTestCase<BucketedSort.ForInts> {
+    @Override
+    public BucketedSort.ForInts build(
+        SortOrder sortOrder,
+        DocValueFormat format,
+        int bucketSize,
+        BucketedSort.ExtraData extra,
+        double[] values
+    ) {
+        return new BucketedSort.ForInts(bigArrays(), sortOrder, format, bucketSize, extra) {
+            @Override
+            public Leaf forLeaf(LeafReaderContext ctx) {
+                return new Leaf(ctx) {
+                    int index = -1;
+
+                    @Override
+                    protected boolean advanceExact(int doc) {
+                        index = doc;
+                        return doc < values.length;
+                    }
+
+                    @Override
+                    protected int docValue() {
+                        return (int) values[index];
+                    }
+                };
+            }
+        };
+    }
+
+    @Override
+    protected SortValue expectedSortValue(double v) {
+        return SortValue.from((long) v);
+    }
+
+    @Override
+    protected double randomValue() {
+        return randomIntBetween(Integer.MIN_VALUE, Integer.MAX_VALUE);
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/sort/BucketedSortForUnsignedLongsTests.java b/server/src/test/java/org/opensearch/search/sort/BucketedSortForUnsignedLongsTests.java
new file mode 100644
index 0000000000000..63eb485ef73b8
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/sort/BucketedSortForUnsignedLongsTests.java
@@ -0,0 +1,58 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.sort;
+
+import org.apache.lucene.index.LeafReaderContext;
+import org.opensearch.search.DocValueFormat;
+
+public class BucketedSortForUnsignedLongsTests extends BucketedSortTestCase<BucketedSort.ForUnsignedLongs> {
+    @Override
+    public BucketedSort.ForUnsignedLongs build(
+        SortOrder sortOrder,
+        DocValueFormat format,
+        int bucketSize,
+        BucketedSort.ExtraData extra,
+        double[] values
+    ) {
+        return new BucketedSort.ForUnsignedLongs(bigArrays(), sortOrder, format, bucketSize, extra) {
+            @Override
+            public Leaf forLeaf(LeafReaderContext ctx) {
+                return new Leaf(ctx) {
+                    int index = -1;
+
+                    @Override
+                    protected boolean advanceExact(int doc) {
+                        index = doc;
+                        return doc < values.length;
+                    }
+
+                    @Override
+                    protected long docValue() {
+                        return (long) values[index];
+                    }
+                };
+            }
+        };
+    }
+
+    @Override
+    protected SortValue expectedSortValue(double v) {
+        return SortValue.fromUnsigned((long) v);
+    }
+
+    @Override
+    protected double randomValue() {
+        return randomUnsignedLong().doubleValue();
+    }
+
+    @Override
+    protected boolean isUnsignedNumeric() {
+        return true;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/sort/BucketedSortTestCase.java b/server/src/test/java/org/opensearch/search/sort/BucketedSortTestCase.java
index cb34298a543a1..649c3f06bbf7c 100644
--- a/server/src/test/java/org/opensearch/search/sort/BucketedSortTestCase.java
+++ b/server/src/test/java/org/opensearch/search/sort/BucketedSortTestCase.java
@@ -40,7 +40,7 @@
 import org.opensearch.common.util.IntArray;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -75,6 +75,11 @@ public abstract class BucketedSortTestCase<T extends BucketedSort> extends OpenS
      */
     protected abstract double randomValue();
 
+    /** A property to indicated the underlying bucket's numeric data type is represented as unsigned numeric */
+    protected boolean isUnsignedNumeric() {
+        return false;
+    }
+
     protected final T build(SortOrder order, int bucketSize, BucketedSort.ExtraData extra, double[] values) {
         DocValueFormat format = randomFrom(DocValueFormat.RAW, DocValueFormat.BINARY, DocValueFormat.BOOLEAN);
         return build(order, format, bucketSize, extra, values);
@@ -194,7 +199,7 @@ public void testManyBuckets() throws IOException {
 
         double[] maxes = new double[buckets.length];
 
-        try (T sort = build(SortOrder.DESC, 1, new double[] { 2, 3, -1 })) {
+        try (T sort = build(SortOrder.DESC, 1, new double[] { 2, 3, isUnsignedNumeric() ? 0 : -1 })) {
             BucketedSort.Leaf leaf = sort.forLeaf(null);
             for (int b : buckets) {
                 maxes[b] = 2;
diff --git a/server/src/test/java/org/opensearch/search/sort/FieldSortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/FieldSortBuilderTests.java
index 44d48e9073e23..8d3e6babf353b 100644
--- a/server/src/test/java/org/opensearch/search/sort/FieldSortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/FieldSortBuilderTests.java
@@ -42,10 +42,9 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.sandbox.document.BigIntegerPoint;
 import org.apache.lucene.sandbox.document.HalfFloatPoint;
-import org.apache.lucene.tests.search.AssertingIndexSearcher;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortedNumericSelector;
@@ -54,17 +53,19 @@
 import org.apache.lucene.search.SortedSetSortField;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.AssertingIndexSearcher;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.mapper.NumberFieldMapper;
-import org.opensearch.index.mapper.TypeFieldMapper;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -78,6 +79,7 @@
 import org.opensearch.search.builder.SearchSourceBuilder;
 
 import java.io.IOException;
+import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -325,7 +327,7 @@ public void testBuildNested() throws IOException {
         comparatorSource = (XFieldComparatorSource) sortField.getComparatorSource();
         nested = comparatorSource.nested();
         assertNotNull(nested);
-        assertEquals(new TermQuery(new Term(TypeFieldMapper.NAME, "__path")), nested.getInnerQuery());
+        assertEquals(new TermQuery(new Term(NestedPathFieldMapper.NAME, "path")), nested.getInnerQuery());
 
         sortBuilder = new FieldSortBuilder("fieldName").setNestedPath("path")
             .setNestedFilter(QueryBuilders.termQuery(MAPPED_STRING_FIELDNAME, "value"));
@@ -504,7 +506,7 @@ public void testGetMaxNumericSortValue() throws IOException {
 
                             case INTEGER:
                                 int v2 = randomInt();
-                                values[i] = (long) v2;
+                                values[i] = (int) v2;
                                 doc.add(new IntPoint(fieldName, v2));
                                 break;
 
@@ -528,16 +530,22 @@ public void testGetMaxNumericSortValue() throws IOException {
 
                             case BYTE:
                                 byte v6 = randomByte();
-                                values[i] = (long) v6;
+                                values[i] = (int) v6;
                                 doc.add(new IntPoint(fieldName, v6));
                                 break;
 
                             case SHORT:
                                 short v7 = randomShort();
-                                values[i] = (long) v7;
+                                values[i] = (int) v7;
                                 doc.add(new IntPoint(fieldName, v7));
                                 break;
 
+                            case UNSIGNED_LONG:
+                                BigInteger v8 = randomUnsignedLong();
+                                values[i] = v8;
+                                doc.add(new BigIntegerPoint(fieldName, v8));
+                                break;
+
                             default:
                                 throw new AssertionError("unknown type " + numberType);
                         }
@@ -546,7 +554,8 @@ public void testGetMaxNumericSortValue() throws IOException {
                     Arrays.sort(values);
                     try (DirectoryReader reader = writer.getReader()) {
                         QueryShardContext newContext = createMockShardContext(new AssertingIndexSearcher(random(), reader));
-                        if (numberType == NumberFieldMapper.NumberType.HALF_FLOAT) {
+                        if (numberType == NumberFieldMapper.NumberType.HALF_FLOAT
+                            || numberType == NumberFieldMapper.NumberType.UNSIGNED_LONG) {
                             assertNull(getMinMaxOrNull(newContext, SortBuilders.fieldSort(fieldName + "-ni")));
                             assertNull(getMinMaxOrNull(newContext, SortBuilders.fieldSort(fieldName)));
                         } else {
diff --git a/server/src/test/java/org/opensearch/search/sort/GeoDistanceSortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/GeoDistanceSortBuilderTests.java
index c14deb6add083..dcbe6f8949179 100644
--- a/server/src/test/java/org/opensearch/search/sort/GeoDistanceSortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/GeoDistanceSortBuilderTests.java
@@ -41,14 +41,14 @@
 import org.opensearch.common.geo.GeoDistance;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.mapper.GeoPointFieldMapper;
 import org.opensearch.index.mapper.MappedFieldType;
-import org.opensearch.index.mapper.TypeFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.query.GeoValidationMethod;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
@@ -552,7 +552,7 @@ public void testBuildNested() throws IOException {
         comparatorSource = (XFieldComparatorSource) sortField.getComparatorSource();
         nested = comparatorSource.nested();
         assertNotNull(nested);
-        assertEquals(new TermQuery(new Term(TypeFieldMapper.NAME, "__path")), nested.getInnerQuery());
+        assertEquals(new TermQuery(new Term(NestedPathFieldMapper.NAME, "path")), nested.getInnerQuery());
 
         sortBuilder = new GeoDistanceSortBuilder("fieldName", 1.0, 1.0).setNestedPath("path")
             .setNestedFilter(QueryBuilders.matchAllQuery());
diff --git a/server/src/test/java/org/opensearch/search/sort/MinAndMaxTests.java b/server/src/test/java/org/opensearch/search/sort/MinAndMaxTests.java
new file mode 100644
index 0000000000000..7557a81db0ad3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/search/sort/MinAndMaxTests.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.search.sort;
+
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.math.BigInteger;
+
+public class MinAndMaxTests extends OpenSearchTestCase {
+
+    public void testCompareMin() {
+        assertEquals(true, new MinAndMax<Long>(0L, 9L).compareMin(15L) < 0); // LONG
+        assertEquals(true, new MinAndMax<Integer>(0, 9).compareMin(15) < 0); // INT
+        assertEquals(true, new MinAndMax<Float>(0f, 9f).compareMin(15f) < 0); // FLOAT
+        assertEquals(true, new MinAndMax<Double>(0d, 9d).compareMin(15d) < 0); // DOUBLE
+        assertEquals(true, new MinAndMax<BigInteger>(BigInteger.valueOf(0), BigInteger.valueOf(9)).compareMin(BigInteger.valueOf(15)) < 0); // BigInteger
+        assertEquals(true, new MinAndMax<BytesRef>(new BytesRef("a"), new BytesRef("b")).compareMin(new BytesRef("c")) < 0); // ByteRef
+        expectThrows(UnsupportedOperationException.class, () -> new MinAndMax<String>("a", "b").compareMin("c"));
+    }
+
+    public void testCompareMax() {
+        assertEquals(true, new MinAndMax<Long>(0L, 9L).compareMax(15L) < 0); // LONG
+        assertEquals(true, new MinAndMax<Integer>(0, 9).compareMax(15) < 0); // INT
+        assertEquals(true, new MinAndMax<Float>(0f, 9f).compareMax(15f) < 0); // FLOAT
+        assertEquals(true, new MinAndMax<Double>(0d, 9d).compareMax(15d) < 0); // DOUBLE
+        assertEquals(true, new MinAndMax<BigInteger>(BigInteger.valueOf(0), BigInteger.valueOf(9)).compareMax(BigInteger.valueOf(15)) < 0); // BigInteger
+        assertEquals(true, new MinAndMax<BytesRef>(new BytesRef("a"), new BytesRef("b")).compareMax(new BytesRef("c")) < 0); // ByteRef
+        expectThrows(UnsupportedOperationException.class, () -> new MinAndMax<String>("a", "b").compareMax("c"));
+    }
+}
diff --git a/server/src/test/java/org/opensearch/search/sort/NestedSortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/NestedSortBuilderTests.java
index 23685594489d6..4b0b2514dfc3d 100644
--- a/server/src/test/java/org/opensearch/search/sort/NestedSortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/NestedSortBuilderTests.java
@@ -32,28 +32,29 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.ConstantScoreQueryBuilder;
 import org.opensearch.index.query.MatchAllQueryBuilder;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.search.SearchModule;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.mockito.Mockito;
 
 import java.io.IOException;
 
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyList;
 
 public class NestedSortBuilderTests extends OpenSearchTestCase {
@@ -83,7 +84,7 @@ protected NamedXContentRegistry xContentRegistry() {
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             NestedSortBuilder testItem = createRandomNestedSort(3);
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             testItem.toXContent(builder, ToXContent.EMPTY_PARAMS);
             XContentBuilder shuffled = shuffleXContent(builder);
             try (XContentParser parser = createParser(shuffled)) {
diff --git a/server/src/test/java/org/opensearch/search/sort/ScoreSortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/ScoreSortBuilderTests.java
index 0d7f9dd213313..eefe3157fe366 100644
--- a/server/src/test/java/org/opensearch/search/sort/ScoreSortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/ScoreSortBuilderTests.java
@@ -33,8 +33,8 @@
 package org.opensearch.search.sort;
 
 import org.apache.lucene.search.SortField;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.DocValueFormat;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/sort/ScriptSortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/ScriptSortBuilderTests.java
index c1e430abbe3d2..a124fdfeeb508 100644
--- a/server/src/test/java/org/opensearch/search/sort/ScriptSortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/ScriptSortBuilderTests.java
@@ -36,14 +36,14 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TermQuery;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource;
 import org.opensearch.index.fielddata.IndexFieldData.XFieldComparatorSource.Nested;
 import org.opensearch.index.fielddata.fieldcomparator.BytesRefFieldComparatorSource;
 import org.opensearch.index.fielddata.fieldcomparator.DoubleValuesComparatorSource;
-import org.opensearch.index.mapper.TypeFieldMapper;
+import org.opensearch.index.mapper.NestedPathFieldMapper;
 import org.opensearch.index.query.MatchNoneQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -344,7 +344,7 @@ public void testBuildNested() throws IOException {
         comparatorSource = (XFieldComparatorSource) sortField.getComparatorSource();
         nested = comparatorSource.nested();
         assertNotNull(nested);
-        assertEquals(new TermQuery(new Term(TypeFieldMapper.NAME, "__path")), nested.getInnerQuery());
+        assertEquals(new TermQuery(new Term(NestedPathFieldMapper.NAME, "path")), nested.getInnerQuery());
 
         sortBuilder = new ScriptSortBuilder(mockScript(MOCK_SCRIPT_NAME), ScriptSortType.NUMBER).setNestedPath("path")
             .setNestedFilter(QueryBuilders.matchAllQuery());
diff --git a/server/src/test/java/org/opensearch/search/sort/SortBuilderTests.java b/server/src/test/java/org/opensearch/search/sort/SortBuilderTests.java
index 36acb1ba2f3e0..2f7463346a325 100644
--- a/server/src/test/java/org/opensearch/search/sort/SortBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/SortBuilderTests.java
@@ -32,15 +32,14 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
@@ -195,7 +194,7 @@ public void testRandomSortBuilders() throws IOException {
                 xContentBuilder.endArray();
             }
             xContentBuilder.endObject();
-            List<SortBuilder<?>> parsedSort = parseSort(Strings.toString(xContentBuilder));
+            List<SortBuilder<?>> parsedSort = parseSort(xContentBuilder.toString());
             assertEquals(testBuilders.size(), parsedSort.size());
             Iterator<SortBuilder<?>> iterator = testBuilders.iterator();
             for (SortBuilder<?> parsedBuilder : parsedSort) {
diff --git a/server/src/test/java/org/opensearch/search/sort/SortOrderTests.java b/server/src/test/java/org/opensearch/search/sort/SortOrderTests.java
index d2c4d248c22ee..a7cec3d12bcaf 100644
--- a/server/src/test/java/org/opensearch/search/sort/SortOrderTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/SortOrderTests.java
@@ -33,7 +33,7 @@
 package org.opensearch.search.sort;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.equalTo;
diff --git a/server/src/test/java/org/opensearch/search/sort/SortValueTests.java b/server/src/test/java/org/opensearch/search/sort/SortValueTests.java
index 08d6952db47fd..91be089526485 100644
--- a/server/src/test/java/org/opensearch/search/sort/SortValueTests.java
+++ b/server/src/test/java/org/opensearch/search/sort/SortValueTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.search.sort;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.test.AbstractNamedWriteableTestCase;
@@ -119,7 +120,7 @@ public void testCompareLongs() {
     }
 
     public String toXContent(SortValue sortValue, DocValueFormat format) {
-        return Strings.toString(new ToXContentFragment() {
+        return Strings.toString(MediaTypeRegistry.JSON, new ToXContentFragment() {
             @Override
             public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
                 builder.field("test");
diff --git a/server/src/test/java/org/opensearch/search/sort/plugin/CustomSortBuilder.java b/server/src/test/java/org/opensearch/search/sort/plugin/CustomSortBuilder.java
index 6ee53a7936320..c3d790cb99cbd 100644
--- a/server/src/test/java/org/opensearch/search/sort/plugin/CustomSortBuilder.java
+++ b/server/src/test/java/org/opensearch/search/sort/plugin/CustomSortBuilder.java
@@ -8,15 +8,13 @@
 
 package org.opensearch.search.sort.plugin;
 
-import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
-
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryRewriteContext;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.sort.BucketedSort;
@@ -28,6 +26,8 @@
 import java.io.IOException;
 import java.util.Objects;
 
+import static org.opensearch.core.xcontent.ConstructingObjectParser.constructorArg;
+
 /**
  * Custom sort builder that just rewrites to a basic field sort
  */
diff --git a/server/src/test/java/org/opensearch/search/suggest/AbstractSuggestionBuilderTestCase.java b/server/src/test/java/org/opensearch/search/suggest/AbstractSuggestionBuilderTestCase.java
index 6e73d5af5d9c0..f3f1ef6d39fff 100644
--- a/server/src/test/java/org/opensearch/search/suggest/AbstractSuggestionBuilderTestCase.java
+++ b/server/src/test/java/org/opensearch/search/suggest/AbstractSuggestionBuilderTestCase.java
@@ -35,17 +35,17 @@
 import org.apache.lucene.analysis.core.SimpleAnalyzer;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -59,8 +59,8 @@
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.suggest.SuggestionSearchContext.SuggestionContext;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
@@ -146,7 +146,7 @@ public void testEqualsAndHashcode() {
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTBUILDERS; runs++) {
             SB suggestionBuilder = randomTestBuilder();
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 xContentBuilder.prettyPrint();
             }
diff --git a/server/src/test/java/org/opensearch/search/suggest/CompletionSuggestionOptionTests.java b/server/src/test/java/org/opensearch/search/suggest/CompletionSuggestionOptionTests.java
index 6fadb4e6fbe72..0f1ea9db0a95a 100644
--- a/server/src/test/java/org/opensearch/search/suggest/CompletionSuggestionOptionTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/CompletionSuggestionOptionTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHitTests;
 import org.opensearch.search.suggest.completion.CompletionSuggestion;
@@ -51,7 +52,7 @@
 import java.util.Set;
 import java.util.function.Predicate;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -126,7 +127,7 @@ private void doTestFromXContent(boolean addRandomFields) throws IOException {
     public void testToXContent() throws IOException {
         Map<String, Set<String>> contexts = Collections.singletonMap("key", Collections.singleton("value"));
         CompletionSuggestion.Entry.Option option = new CompletionSuggestion.Entry.Option(1, new Text("someText"), 1.3f, contexts);
-        BytesReference xContent = toXContent(option, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(option, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals("{\"text\":\"someText\",\"score\":1.3,\"contexts\":{\"key\":[\"value\"]}}", xContent.utf8ToString());
     }
 }
diff --git a/server/src/test/java/org/opensearch/search/suggest/SuggestBuilderTests.java b/server/src/test/java/org/opensearch/search/suggest/SuggestBuilderTests.java
index 709cf0c6a763f..49f2b7869010b 100644
--- a/server/src/test/java/org/opensearch/search/suggest/SuggestBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/SuggestBuilderTests.java
@@ -32,20 +32,20 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.suggest.completion.CompletionSuggesterBuilderTests;
 import org.opensearch.search.suggest.phrase.PhraseSuggestionBuilderTests;
 import org.opensearch.search.suggest.term.TermSuggestionBuilderTests;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
@@ -82,7 +82,7 @@ public static void afterClass() {
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_RUNS; runs++) {
             SuggestBuilder suggestBuilder = randomSuggestBuilder();
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 xContentBuilder.prettyPrint();
             }
@@ -102,11 +102,9 @@ public void testFromXContent() throws IOException {
     public void testEqualsAndHashcode() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_RUNS; runs++) {
             // explicit about type parameters, see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=481649
-            EqualsHashCodeTestUtils.<SuggestBuilder>checkEqualsAndHashCode(
-                randomSuggestBuilder(),
-                original -> { return copyWriteable(original, namedWriteableRegistry, SuggestBuilder::new); },
-                this::createMutation
-            );
+            EqualsHashCodeTestUtils.<SuggestBuilder>checkEqualsAndHashCode(randomSuggestBuilder(), original -> {
+                return copyWriteable(original, namedWriteableRegistry, SuggestBuilder::new);
+            }, this::createMutation);
         }
     }
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/SuggestTests.java b/server/src/test/java/org/opensearch/search/suggest/SuggestTests.java
index 5f48e11357b9d..466eb33f3e6b7 100644
--- a/server/src/test/java/org/opensearch/search/suggest/SuggestTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/SuggestTests.java
@@ -33,20 +33,21 @@
 package org.opensearch.search.suggest;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.suggest.Suggest.Suggestion;
@@ -66,9 +67,9 @@
 
 import static java.util.Collections.emptyList;
 import static org.opensearch.common.xcontent.XContentHelper.stripWhitespace;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureFieldName;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -162,7 +163,7 @@ public void testToXContent() throws IOException {
         PhraseSuggestion suggestion = new PhraseSuggestion("suggestionName", 5);
         suggestion.addTerm(entry);
         Suggest suggest = new Suggest(Collections.singletonList(suggestion));
-        BytesReference xContent = toXContent(suggest, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(suggest, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             stripWhitespace(
                 "{"
diff --git a/server/src/test/java/org/opensearch/search/suggest/SuggestionEntryTests.java b/server/src/test/java/org/opensearch/search/suggest/SuggestionEntryTests.java
index 2ce344afdb854..09551e6453ee7 100644
--- a/server/src/test/java/org/opensearch/search/suggest/SuggestionEntryTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/SuggestionEntryTests.java
@@ -32,11 +32,12 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.Suggest.Suggestion.Entry;
 import org.opensearch.search.suggest.Suggest.Suggestion.Entry.Option;
 import org.opensearch.search.suggest.completion.CompletionSuggestion;
@@ -52,8 +53,8 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -156,7 +157,7 @@ public void testToXContent() throws IOException {
         );
         PhraseSuggestion.Entry phraseEntry = new PhraseSuggestion.Entry(new Text("entryText"), 42, 313);
         phraseEntry.addOption(phraseOption);
-        BytesReference xContent = toXContent(phraseEntry, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(phraseEntry, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             "{\"text\":\"entryText\","
                 + "\"offset\":42,"
@@ -173,7 +174,7 @@ public void testToXContent() throws IOException {
         TermSuggestion.Entry.Option termOption = new TermSuggestion.Entry.Option(new Text("termSuggestOption"), 42, 3.13f);
         TermSuggestion.Entry termEntry = new TermSuggestion.Entry(new Text("entryText"), 42, 313);
         termEntry.addOption(termOption);
-        xContent = toXContent(termEntry, XContentType.JSON, randomBoolean());
+        xContent = toXContent(termEntry, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             "{\"text\":\"entryText\","
                 + "\"offset\":42,"
@@ -194,7 +195,7 @@ public void testToXContent() throws IOException {
         );
         CompletionSuggestion.Entry completionEntry = new CompletionSuggestion.Entry(new Text("entryText"), 42, 313);
         completionEntry.addOption(completionOption);
-        xContent = toXContent(completionEntry, XContentType.JSON, randomBoolean());
+        xContent = toXContent(completionEntry, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             "{\"text\":\"entryText\","
                 + "\"offset\":42,"
diff --git a/server/src/test/java/org/opensearch/search/suggest/SuggestionOptionTests.java b/server/src/test/java/org/opensearch/search/suggest/SuggestionOptionTests.java
index 9ba52e8cd6eb5..39c061f2b6586 100644
--- a/server/src/test/java/org/opensearch/search/suggest/SuggestionOptionTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/SuggestionOptionTests.java
@@ -32,19 +32,20 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.Suggest.Suggestion.Entry.Option;
 import org.opensearch.search.suggest.phrase.PhraseSuggestion;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -93,7 +94,7 @@ private void doTestFromXContent(boolean addRandomFields) throws IOException {
 
     public void testToXContent() throws IOException {
         Option option = new PhraseSuggestion.Entry.Option(new Text("someText"), new Text("somethingHighlighted"), 1.3f, true);
-        BytesReference xContent = toXContent(option, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(option, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals(
             ("{"
                 + "  \"text\": \"someText\","
diff --git a/server/src/test/java/org/opensearch/search/suggest/SuggestionTests.java b/server/src/test/java/org/opensearch/search/suggest/SuggestionTests.java
index 8ce8c2c7c94d2..c2be83b593a67 100644
--- a/server/src/test/java/org/opensearch/search/suggest/SuggestionTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/SuggestionTests.java
@@ -32,16 +32,17 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedObjectNotFoundException;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedObjectNotFoundException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.search.suggest.Suggest.Suggestion;
 import org.opensearch.search.suggest.Suggest.Suggestion.Entry;
@@ -58,8 +59,8 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -229,7 +230,7 @@ public void testToXContent() throws IOException {
             entry.addOption(option);
             PhraseSuggestion suggestion = new PhraseSuggestion("suggestionName", 5);
             suggestion.addTerm(entry);
-            BytesReference xContent = toXContent(suggestion, XContentType.JSON, params, randomBoolean());
+            BytesReference xContent = toXContent(suggestion, MediaTypeRegistry.JSON, params, randomBoolean());
             assertEquals(
                 ("{"
                     + "  \"phrase#suggestionName\": ["
@@ -262,7 +263,7 @@ public void testToXContent() throws IOException {
             entry.addOption(option);
             PhraseSuggestion suggestion = new PhraseSuggestion("suggestionName", 5);
             suggestion.addTerm(entry);
-            BytesReference xContent = toXContent(suggestion, XContentType.JSON, params, randomBoolean());
+            BytesReference xContent = toXContent(suggestion, MediaTypeRegistry.JSON, params, randomBoolean());
             assertEquals(
                 ("{"
                     + "  \"phrase#suggestionName\": ["
@@ -290,7 +291,7 @@ public void testToXContent() throws IOException {
             entry.addOption(option);
             TermSuggestion suggestion = new TermSuggestion("suggestionName", 5, SortBy.SCORE);
             suggestion.addTerm(entry);
-            BytesReference xContent = toXContent(suggestion, XContentType.JSON, params, randomBoolean());
+            BytesReference xContent = toXContent(suggestion, MediaTypeRegistry.JSON, params, randomBoolean());
             assertEquals(
                 ("{"
                     + "  \"term#suggestionName\": ["
@@ -318,7 +319,7 @@ public void testToXContent() throws IOException {
             entry.addOption(option);
             CompletionSuggestion suggestion = new CompletionSuggestion("suggestionName", 5, randomBoolean());
             suggestion.addTerm(entry);
-            BytesReference xContent = toXContent(suggestion, XContentType.JSON, params, randomBoolean());
+            BytesReference xContent = toXContent(suggestion, MediaTypeRegistry.JSON, params, randomBoolean());
             assertEquals(
                 ("{"
                     + "  \"completion#suggestionName\": ["
diff --git a/server/src/test/java/org/opensearch/search/suggest/TermSuggestionOptionTests.java b/server/src/test/java/org/opensearch/search/suggest/TermSuggestionOptionTests.java
index 81fc1a7a89483..d54ae78550b68 100644
--- a/server/src/test/java/org/opensearch/search/suggest/TermSuggestionOptionTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/TermSuggestionOptionTests.java
@@ -32,18 +32,19 @@
 
 package org.opensearch.search.suggest;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.term.TermSuggestion.Entry.Option;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
-import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.test.XContentTestUtils.insertRandomFields;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
@@ -90,7 +91,7 @@ private void doTestFromXContent(boolean addRandomFields) throws IOException {
 
     public void testToXContent() throws IOException {
         Option option = new Option(new Text("someText"), 100, 1.3f);
-        BytesReference xContent = toXContent(option, XContentType.JSON, randomBoolean());
+        BytesReference xContent = toXContent(option, MediaTypeRegistry.JSON, randomBoolean());
         assertEquals("{\"text\":\"someText\",\"score\":1.3,\"freq\":100}", xContent.utf8ToString());
     }
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/CategoryContextMappingTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/CategoryContextMappingTests.java
index dc6cfdd281980..ff85a912552fc 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/CategoryContextMappingTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/CategoryContextMappingTests.java
@@ -41,15 +41,14 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.search.suggest.document.ContextSuggestField;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.CompletionFieldMapper.CompletionFieldType;
 import org.opensearch.index.mapper.DocumentMapper;
 import org.opensearch.index.mapper.KeywordFieldMapper;
@@ -75,21 +74,20 @@
 public class CategoryContextMappingTests extends OpenSearchSingleNodeTestCase {
 
     public void testIndexingWithNoContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -117,7 +115,7 @@ public void testIndexingWithNoContexts() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -125,21 +123,20 @@ public void testIndexingWithNoContexts() throws Exception {
     }
 
     public void testIndexingWithSimpleContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -162,7 +159,7 @@ public void testIndexingWithSimpleContexts() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -170,21 +167,20 @@ public void testIndexingWithSimpleContexts() throws Exception {
     }
 
     public void testIndexingWithSimpleNumberContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -207,7 +203,7 @@ public void testIndexingWithSimpleNumberContexts() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -215,21 +211,20 @@ public void testIndexingWithSimpleNumberContexts() throws Exception {
     }
 
     public void testIndexingWithSimpleBooleanContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -252,7 +247,7 @@ public void testIndexingWithSimpleBooleanContexts() throws Exception {
                         .endArray()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -260,21 +255,20 @@ public void testIndexingWithSimpleBooleanContexts() throws Exception {
     }
 
     public void testIndexingWithSimpleNULLContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -293,7 +287,7 @@ public void testIndexingWithSimpleNULLContexts() throws Exception {
 
         Exception e = expectThrows(
             MapperParsingException.class,
-            () -> defaultMapper.parse(new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON))
+            () -> defaultMapper.parse(new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON))
         );
         assertEquals(
             "contexts must be a string, number or boolean or a list of string, number or boolean, but was [VALUE_NULL]",
@@ -302,21 +296,20 @@ public void testIndexingWithSimpleNULLContexts() throws Exception {
     }
 
     public void testIndexingWithContextList() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -337,7 +330,7 @@ public void testIndexingWithContextList() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -345,21 +338,20 @@ public void testIndexingWithContextList() throws Exception {
     }
 
     public void testIndexingWithMixedTypeContextList() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -380,7 +372,7 @@ public void testIndexingWithMixedTypeContextList() throws Exception {
                         .endObject()
                         .endObject()
                 ),
-                XContentType.JSON
+                MediaTypeRegistry.JSON
             )
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
@@ -388,21 +380,20 @@ public void testIndexingWithMixedTypeContextList() throws Exception {
     }
 
     public void testIndexingWithMixedTypeContextListHavingNULL() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -419,31 +410,30 @@ public void testIndexingWithMixedTypeContextListHavingNULL() throws Exception {
 
         Exception e = expectThrows(
             MapperParsingException.class,
-            () -> defaultMapper.parse(new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON))
+            () -> defaultMapper.parse(new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON))
         );
         assertEquals("context array must have string, number or boolean values, but was [VALUE_NULL]", e.getCause().getMessage());
     }
 
     public void testIndexingWithMultipleContexts() throws Exception {
-        String mapping = Strings.toString(
-            jsonBuilder().startObject()
-                .startObject("properties")
-                .startObject("completion")
-                .field("type", "completion")
-                .startArray("contexts")
-                .startObject()
-                .field("name", "ctx")
-                .field("type", "category")
-                .endObject()
-                .startObject()
-                .field("name", "type")
-                .field("type", "category")
-                .endObject()
-                .endArray()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        String mapping = jsonBuilder().startObject()
+            .startObject("properties")
+            .startObject("completion")
+            .field("type", "completion")
+            .startArray("contexts")
+            .startObject()
+            .field("name", "ctx")
+            .field("type", "category")
+            .endObject()
+            .startObject()
+            .field("name", "type")
+            .field("type", "category")
+            .endObject()
+            .endArray()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
 
         DocumentMapper defaultMapper = createIndex("test").mapperService()
             .documentMapperParser()
@@ -462,7 +452,7 @@ public void testIndexingWithMultipleContexts() throws Exception {
             .endArray()
             .endObject();
         ParsedDocument parsedDocument = defaultMapper.parse(
-            new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON)
+            new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON)
         );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertContextSuggestFields(fields, 3);
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/CategoryQueryContextTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/CategoryQueryContextTests.java
index dcf6663a54802..0d03dbfa622d6 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/CategoryQueryContextTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/CategoryQueryContextTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.completion.context.CategoryQueryContext;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggesterBuilderTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggesterBuilderTests.java
index 3ac81949f2228..83a3fed411601 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggesterBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggesterBuilderTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.search.suggest.completion;
 
 import org.apache.lucene.analysis.core.SimpleAnalyzer;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.mapper.CompletionFieldMapper.CompletionFieldType;
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggestionTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggestionTests.java
index a618fffea3368..8398ec696c43c 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggestionTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/CompletionSuggestionTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.text.Text;
+import org.opensearch.core.common.text.Text;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/FuzzyOptionsTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/FuzzyOptionsTests.java
index bc4f4e029e408..8179d448e2058 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/FuzzyOptionsTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/FuzzyOptionsTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/GeoContextMappingTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/GeoContextMappingTests.java
index 1a1f3b33f0646..07f3526dd2bb0 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/GeoContextMappingTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/GeoContextMappingTests.java
@@ -34,12 +34,12 @@
 
 import org.apache.lucene.index.IndexableField;
 import org.opensearch.OpenSearchParseException;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.ParsedDocument;
@@ -53,8 +53,8 @@
 import java.util.Collection;
 import java.util.List;
 
-import static org.opensearch.geometry.utils.Geohash.addNeighborsAtLevel;
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.geometry.utils.Geohash.addNeighborsAtLevel;
 import static org.opensearch.search.suggest.completion.CategoryContextMappingTests.assertContextSuggestFields;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.in;
@@ -102,7 +102,7 @@ public void testIndexingWithNoContexts() throws Exception {
                             .endArray()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
@@ -147,7 +147,7 @@ public void testIndexingWithSimpleContexts() throws Exception {
                             .endArray()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
@@ -196,7 +196,7 @@ public void testIndexingWithContextList() throws Exception {
                             .endObject()
                             .endObject()
                     ),
-                    XContentType.JSON
+                    MediaTypeRegistry.JSON
                 )
             );
         IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
@@ -237,7 +237,7 @@ public void testIndexingWithMultipleContexts() throws Exception {
             .endArray()
             .endObject();
         ParsedDocument parsedDocument = mapperService.documentMapper()
-            .parse(new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON));
+            .parse(new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON));
         IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
         assertContextSuggestFields(fields, 3);
     }
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/GeoQueryContextTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/GeoQueryContextTests.java
index 1f4ced0d5df0c..f52009d36c382 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/GeoQueryContextTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/GeoQueryContextTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.geo.GeoPoint;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.completion.context.GeoQueryContext;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/QueryContextTestCase.java b/server/src/test/java/org/opensearch/search/suggest/completion/QueryContextTestCase.java
index 34acc0eed2f54..c79cdc256d055 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/QueryContextTestCase.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/QueryContextTestCase.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/search/suggest/completion/RegexOptionsTests.java b/server/src/test/java/org/opensearch/search/suggest/completion/RegexOptionsTests.java
index 57bc0e5708f4d..9d158f57703b6 100644
--- a/server/src/test/java/org/opensearch/search/suggest/completion/RegexOptionsTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/completion/RegexOptionsTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.completion;
 
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.index.query.RegexpFlag;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorTests.java b/server/src/test/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorTests.java
index 86b2f08f3855e..25ee8f95b8acb 100644
--- a/server/src/test/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/phrase/DirectCandidateGeneratorTests.java
@@ -46,14 +46,14 @@
 import org.apache.lucene.search.spell.SuggestMode;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -140,7 +140,7 @@ private static DirectCandidateGeneratorBuilder mutate(DirectCandidateGeneratorBu
     public void testFromXContent() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_RUNS; runs++) {
             DirectCandidateGeneratorBuilder generator = randomCandidateGenerator();
-            XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+            XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
             if (randomBoolean()) {
                 builder.prettyPrint();
             }
diff --git a/server/src/test/java/org/opensearch/search/suggest/phrase/LaplaceModelTests.java b/server/src/test/java/org/opensearch/search/suggest/phrase/LaplaceModelTests.java
index 4406d48b5d3c3..149364495535d 100644
--- a/server/src/test/java/org/opensearch/search/suggest/phrase/LaplaceModelTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/phrase/LaplaceModelTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.phrase;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/phrase/LinearInterpolationModelTests.java b/server/src/test/java/org/opensearch/search/suggest/phrase/LinearInterpolationModelTests.java
index dbf4407ce1d11..02635a5820444 100644
--- a/server/src/test/java/org/opensearch/search/suggest/phrase/LinearInterpolationModelTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/phrase/LinearInterpolationModelTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.phrase;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/phrase/SmoothingModelTestCase.java b/server/src/test/java/org/opensearch/search/suggest/phrase/SmoothingModelTestCase.java
index 84753de62a6c5..30bb48af1fd7a 100644
--- a/server/src/test/java/org/opensearch/search/suggest/phrase/SmoothingModelTestCase.java
+++ b/server/src/test/java/org/opensearch/search/suggest/phrase/SmoothingModelTestCase.java
@@ -43,13 +43,13 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.MultiTerms;
 import org.apache.lucene.store.ByteBuffersDirectory;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.BytesRefs;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
@@ -101,7 +101,7 @@ public static void afterClass() throws Exception {
      */
     public void testFromXContent() throws IOException {
         SmoothingModel testModel = createTestModel();
-        XContentBuilder contentBuilder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder contentBuilder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             contentBuilder.prettyPrint();
         }
diff --git a/server/src/test/java/org/opensearch/search/suggest/phrase/StupidBackoffModelTests.java b/server/src/test/java/org/opensearch/search/suggest/phrase/StupidBackoffModelTests.java
index 525ec35bc252e..116eef4db85f4 100644
--- a/server/src/test/java/org/opensearch/search/suggest/phrase/StupidBackoffModelTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/phrase/StupidBackoffModelTests.java
@@ -32,7 +32,7 @@
 
 package org.opensearch.search.suggest.phrase;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/search/suggest/term/TermSuggestionBuilderTests.java b/server/src/test/java/org/opensearch/search/suggest/term/TermSuggestionBuilderTests.java
index ad7a548e13d51..8a2f199314465 100644
--- a/server/src/test/java/org/opensearch/search/suggest/term/TermSuggestionBuilderTests.java
+++ b/server/src/test/java/org/opensearch/search/suggest/term/TermSuggestionBuilderTests.java
@@ -34,8 +34,8 @@
 
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
 
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.suggest.AbstractSuggestionBuilderTestCase;
 import org.opensearch.search.suggest.SortBy;
 import org.opensearch.search.suggest.SuggestBuilder;
diff --git a/server/src/test/java/org/opensearch/snapshots/BlobStoreFormatTests.java b/server/src/test/java/org/opensearch/snapshots/BlobStoreFormatTests.java
index 0bf2d2b6a7474..03f0d27188027 100644
--- a/server/src/test/java/org/opensearch/snapshots/BlobStoreFormatTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/BlobStoreFormatTests.java
@@ -34,19 +34,26 @@
 
 import org.opensearch.OpenSearchCorruptionException;
 import org.opensearch.OpenSearchParseException;
+import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.fs.FsBlobContainer;
 import org.opensearch.common.blobstore.fs.FsBlobStore;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.common.blobstore.stream.read.ReadContext;
+import org.opensearch.common.blobstore.stream.write.WriteContext;
+import org.opensearch.common.compress.DeflateCompressor;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.translog.BufferedChecksumStreamOutput;
 import org.opensearch.repositories.blobstore.ChecksumBlobStoreFormat;
 import org.opensearch.test.OpenSearchTestCase;
@@ -54,7 +61,10 @@
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Path;
 import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.greaterThan;
 
@@ -111,14 +121,70 @@ public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params par
         }
     }
 
+    public void testBlobStoreAsyncOperations() throws IOException, InterruptedException {
+        BlobStore blobStore = createTestBlobStore();
+        MockFsVerifyingBlobContainer mockBlobContainer = new MockFsVerifyingBlobContainer(
+            (FsBlobStore) blobStore,
+            BlobPath.cleanPath(),
+            null
+        );
+        ChecksumBlobStoreFormat<BlobObj> checksumSMILE = new ChecksumBlobStoreFormat<>(BLOB_CODEC, "%s", BlobObj::fromXContent);
+
+        CountDownLatch latch = new CountDownLatch(2);
+
+        ActionListener<Void> actionListener = new ActionListener<>() {
+            @Override
+            public void onResponse(Void unused) {
+                logger.info("---> Async write succeeded");
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                logger.info("---> Failure in async write");
+                throw new RuntimeException("async write should not fail");
+            }
+        };
+
+        // Write blobs in different formats
+        checksumSMILE.writeAsync(
+            new BlobObj("checksum smile"),
+            mockBlobContainer,
+            "check-smile",
+            CompressorRegistry.none(),
+            actionListener
+        );
+        checksumSMILE.writeAsync(
+            new BlobObj("checksum smile compressed"),
+            mockBlobContainer,
+            "check-smile-comp",
+            CompressorRegistry.getCompressor(DeflateCompressor.NAME),
+            actionListener
+        );
+
+        latch.await();
+
+        // Assert that all checksum blobs can be read
+        assertEquals(checksumSMILE.read(mockBlobContainer.getDelegate(), "check-smile", xContentRegistry()).getText(), "checksum smile");
+        assertEquals(
+            checksumSMILE.read(mockBlobContainer.getDelegate(), "check-smile-comp", xContentRegistry()).getText(),
+            "checksum smile compressed"
+        );
+    }
+
     public void testBlobStoreOperations() throws IOException {
         BlobStore blobStore = createTestBlobStore();
         BlobContainer blobContainer = blobStore.blobContainer(BlobPath.cleanPath());
         ChecksumBlobStoreFormat<BlobObj> checksumSMILE = new ChecksumBlobStoreFormat<>(BLOB_CODEC, "%s", BlobObj::fromXContent);
 
         // Write blobs in different formats
-        checksumSMILE.write(new BlobObj("checksum smile"), blobContainer, "check-smile", false);
-        checksumSMILE.write(new BlobObj("checksum smile compressed"), blobContainer, "check-smile-comp", true);
+        checksumSMILE.write(new BlobObj("checksum smile"), blobContainer, "check-smile", CompressorRegistry.none());
+        checksumSMILE.write(
+            new BlobObj("checksum smile compressed"),
+            blobContainer,
+            "check-smile-comp",
+            CompressorRegistry.getCompressor(DeflateCompressor.NAME)
+        );
 
         // Assert that all checksum blobs can be read
         assertEquals(checksumSMILE.read(blobContainer, "check-smile", xContentRegistry()).getText(), "checksum smile");
@@ -134,8 +200,8 @@ public void testCompressionIsApplied() throws IOException {
         }
         ChecksumBlobStoreFormat<BlobObj> checksumFormat = new ChecksumBlobStoreFormat<>(BLOB_CODEC, "%s", BlobObj::fromXContent);
         BlobObj blobObj = new BlobObj(veryRedundantText.toString());
-        checksumFormat.write(blobObj, blobContainer, "blob-comp", true);
-        checksumFormat.write(blobObj, blobContainer, "blob-not-comp", false);
+        checksumFormat.write(blobObj, blobContainer, "blob-comp", CompressorRegistry.getCompressor(DeflateCompressor.NAME));
+        checksumFormat.write(blobObj, blobContainer, "blob-not-comp", CompressorRegistry.none());
         Map<String, BlobMetadata> blobs = blobContainer.listBlobsByPrefix("blob-");
         assertEquals(blobs.size(), 2);
         assertThat(blobs.get("blob-not-comp").length(), greaterThan(blobs.get("blob-comp").length()));
@@ -147,7 +213,7 @@ public void testBlobCorruption() throws IOException {
         String testString = randomAlphaOfLength(randomInt(10000));
         BlobObj blobObj = new BlobObj(testString);
         ChecksumBlobStoreFormat<BlobObj> checksumFormat = new ChecksumBlobStoreFormat<>(BLOB_CODEC, "%s", BlobObj::fromXContent);
-        checksumFormat.write(blobObj, blobContainer, "test-path", randomBoolean());
+        checksumFormat.write(blobObj, blobContainer, "test-path", randomFrom(CompressorRegistry.registeredCompressors().values()));
         assertEquals(checksumFormat.read(blobContainer, "test-path", xContentRegistry()).getText(), testString);
         randomCorruption(blobContainer, "test-path");
         try {
@@ -188,4 +254,35 @@ private long checksum(byte[] buffer) throws IOException {
             }
         }
     }
+
+    public static class MockFsVerifyingBlobContainer extends FsBlobContainer implements AsyncMultiStreamBlobContainer {
+
+        private BlobContainer delegate;
+
+        public MockFsVerifyingBlobContainer(FsBlobStore blobStore, BlobPath blobPath, Path path) {
+            super(blobStore, blobPath, path);
+            delegate = blobStore.blobContainer(BlobPath.cleanPath());
+        }
+
+        @Override
+        public void asyncBlobUpload(WriteContext writeContext, ActionListener<Void> completionListener) throws IOException {
+            InputStream inputStream = writeContext.getStreamProvider(Integer.MAX_VALUE).provideStream(0).getInputStream();
+            delegate.writeBlob(writeContext.getFileName(), inputStream, writeContext.getFileSize(), true);
+            completionListener.onResponse(null);
+        }
+
+        @Override
+        public void readBlobAsync(String blobName, ActionListener<ReadContext> listener) {
+            throw new RuntimeException("read not supported");
+        }
+
+        @Override
+        public boolean remoteIntegrityCheckSupported() {
+            return false;
+        }
+
+        public BlobContainer getDelegate() {
+            return delegate;
+        }
+    }
 }
diff --git a/server/src/test/java/org/opensearch/snapshots/InternalSnapshotsInfoServiceTests.java b/server/src/test/java/org/opensearch/snapshots/InternalSnapshotsInfoServiceTests.java
index 6c789ae6d98cd..88de234d3449b 100644
--- a/server/src/test/java/org/opensearch/snapshots/InternalSnapshotsInfoServiceTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/InternalSnapshotsInfoServiceTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.snapshots;
 
-import com.carrotsearch.hppc.IntHashSet;
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.ClusterState;
@@ -54,10 +53,9 @@
 import org.opensearch.cluster.service.ClusterApplier;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.repositories.FilterRepository;
 import org.opensearch.repositories.IndexId;
@@ -72,6 +70,8 @@
 import org.junit.Before;
 
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -290,7 +290,7 @@ public IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, In
         assertThat("Expecting all snapshot shard size fetches to execute a Reroute", reroutes.get(), equalTo(maxShardsToCreate));
     }
 
-    public void testNoLongerMaster() throws Exception {
+    public void testNoLongerClusterManager() throws Exception {
         final InternalSnapshotsInfoService snapshotsInfoService = new InternalSnapshotsInfoService(
             Settings.EMPTY,
             clusterService,
@@ -310,18 +310,18 @@ public IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, In
             final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
             final int nbShards = randomIntBetween(1, 5);
             applyClusterState(
-                "restore-indices-when-master-" + indexName,
+                "restore-indices-when-cluster-manager-" + indexName,
                 clusterState -> addUnassignedShards(clusterState, indexName, nbShards)
             );
         }
 
-        applyClusterState("demote-current-master", this::demoteMasterNode);
+        applyClusterState("demote-current-cluster-manager", this::demoteClusterManagerNode);
 
         for (int i = 0; i < randomIntBetween(1, 10); i++) {
             final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
             final int nbShards = randomIntBetween(1, 5);
             applyClusterState(
-                "restore-indices-when-no-longer-master-" + indexName,
+                "restore-indices-when-no-longer-cluster-manager-" + indexName,
                 clusterState -> addUnassignedShards(clusterState, indexName, nbShards)
             );
         }
@@ -457,12 +457,12 @@ private ClusterState addUnassignedShards(final ClusterState currentState, String
         final Index index = indexMetadata.getIndex();
 
         final RoutingTable.Builder routingTable = RoutingTable.builder(currentState.routingTable());
-        routingTable.add(IndexRoutingTable.builder(index).initializeAsNewRestore(indexMetadata, recoverySource, new IntHashSet()).build());
+        routingTable.add(IndexRoutingTable.builder(index).initializeAsNewRestore(indexMetadata, recoverySource, new HashSet<>()).build());
 
         final RestoreInProgress.Builder restores = new RestoreInProgress.Builder(
             currentState.custom(RestoreInProgress.TYPE, RestoreInProgress.EMPTY)
         );
-        final ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shards = ImmutableOpenMap.builder();
+        final Map<ShardId, RestoreInProgress.ShardRestoreStatus> shards = new HashMap<>();
         for (int i = 0; i < indexMetadata.getNumberOfShards(); i++) {
             shards.put(new ShardId(index, i), new RestoreInProgress.ShardRestoreStatus(clusterService.state().nodes().getLocalNodeId()));
         }
@@ -473,7 +473,7 @@ private ClusterState addUnassignedShards(final ClusterState currentState, String
                 recoverySource.snapshot(),
                 RestoreInProgress.State.INIT,
                 Collections.singletonList(indexName),
-                shards.build()
+                shards
             )
         );
 
@@ -484,7 +484,7 @@ private ClusterState addUnassignedShards(final ClusterState currentState, String
             .build();
     }
 
-    private ClusterState demoteMasterNode(final ClusterState currentState) {
+    private ClusterState demoteClusterManagerNode(final ClusterState currentState) {
         final DiscoveryNode node = new DiscoveryNode(
             "other",
             OpenSearchTestCase.buildNewFakeTransportAddress(),
@@ -495,7 +495,7 @@ private ClusterState demoteMasterNode(final ClusterState currentState) {
         assertThat(currentState.nodes().get(node.getId()), nullValue());
 
         return ClusterState.builder(currentState)
-            .nodes(DiscoveryNodes.builder(currentState.nodes()).add(node).masterNodeId(node.getId()))
+            .nodes(DiscoveryNodes.builder(currentState.nodes()).add(node).clusterManagerNodeId(node.getId()))
             .build();
     }
 
diff --git a/server/src/test/java/org/opensearch/snapshots/RepositoriesMetadataSerializationTests.java b/server/src/test/java/org/opensearch/snapshots/RepositoriesMetadataSerializationTests.java
index b0be4f2a711df..8550316a666e8 100644
--- a/server/src/test/java/org/opensearch/snapshots/RepositoriesMetadataSerializationTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/RepositoriesMetadataSerializationTests.java
@@ -34,13 +34,14 @@
 
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.Diff;
+import org.opensearch.cluster.metadata.CryptoMetadata;
 import org.opensearch.cluster.metadata.Metadata.Custom;
 import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractDiffableSerializationTestCase;
 
 import java.io.IOException;
@@ -57,13 +58,18 @@ protected Custom createTestInstance() {
         for (int i = 0; i < numberOfRepositories; i++) {
             // divide by 2 to not overflow when adding to this number for the pending generation below
             final long generation = randomNonNegativeLong() / 2L;
+            CryptoMetadata cryptoMetadata = null;
+            if (randomBoolean()) {
+                cryptoMetadata = new CryptoMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings());
+            }
             entries.add(
                 new RepositoryMetadata(
                     randomAlphaOfLength(10),
                     randomAlphaOfLength(10),
                     randomSettings(),
                     generation,
-                    generation + randomLongBetween(0, generation)
+                    generation + randomLongBetween(0, generation),
+                    cryptoMetadata
                 )
             );
         }
@@ -81,7 +87,11 @@ protected Custom mutateInstance(Custom instance) {
         List<RepositoryMetadata> entries = new ArrayList<>(((RepositoriesMetadata) instance).repositories());
         boolean addEntry = entries.isEmpty() ? true : randomBoolean();
         if (addEntry) {
-            entries.add(new RepositoryMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings()));
+            CryptoMetadata cryptoMetadata = null;
+            if (randomBoolean()) {
+                cryptoMetadata = new CryptoMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings());
+            }
+            entries.add(new RepositoryMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings(), cryptoMetadata));
         } else {
             entries.remove(randomIntBetween(0, entries.size() - 1));
         }
@@ -114,7 +124,11 @@ protected Custom makeTestChanges(Custom testInstance) {
             // add some elements
             int addElements = randomInt(10);
             for (int i = 0; i < addElements; i++) {
-                repos.add(new RepositoryMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings()));
+                CryptoMetadata cryptoMetadata = null;
+                if (randomBoolean()) {
+                    cryptoMetadata = new CryptoMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings());
+                }
+                repos.add(new RepositoryMetadata(randomAlphaOfLength(10), randomAlphaOfLength(10), randomSettings(), cryptoMetadata));
             }
         }
         return new RepositoriesMetadata(repos);
diff --git a/server/src/test/java/org/opensearch/snapshots/RestoreServiceTests.java b/server/src/test/java/org/opensearch/snapshots/RestoreServiceTests.java
index e607e283f4da1..b56f1b47edc33 100644
--- a/server/src/test/java/org/opensearch/snapshots/RestoreServiceTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/RestoreServiceTests.java
@@ -36,7 +36,7 @@
 import org.opensearch.cluster.metadata.DataStream;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Collections;
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotInfoTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotInfoTests.java
index 8320d73d396ea..850a392c9619c 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotInfoTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotInfoTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.snapshots;
 
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.AbstractWireSerializingTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
@@ -73,6 +73,8 @@ protected SnapshotInfo createTestInstance() {
 
         Map<String, Object> userMetadata = randomUserMetadata();
 
+        Boolean remoteStoreIndexShallowCopy = randomBoolean() ? null : randomBoolean();
+
         return new SnapshotInfo(
             snapshotId,
             indices,
@@ -83,7 +85,8 @@ protected SnapshotInfo createTestInstance() {
             totalShards,
             shardFailures,
             includeGlobalState,
-            userMetadata
+            userMetadata,
+            remoteStoreIndexShallowCopy
         );
     }
 
@@ -94,7 +97,7 @@ protected Writeable.Reader<SnapshotInfo> instanceReader() {
 
     @Override
     protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
-        switch (randomIntBetween(0, 8)) {
+        switch (randomIntBetween(0, 9)) {
             case 0:
                 SnapshotId snapshotId = new SnapshotId(
                     randomValueOtherThan(instance.snapshotId().getName(), () -> randomAlphaOfLength(5)),
@@ -110,7 +113,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 1:
                 int indicesSize = randomValueOtherThan(instance.indices().size(), () -> randomIntBetween(1, 10));
@@ -127,7 +131,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 2:
                 return new SnapshotInfo(
@@ -140,7 +145,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 3:
                 return new SnapshotInfo(
@@ -153,7 +159,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 4:
                 return new SnapshotInfo(
@@ -166,7 +173,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 5:
                 int totalShards = randomValueOtherThan(instance.totalShards(), () -> randomIntBetween(0, 100));
@@ -191,7 +199,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     totalShards,
                     shardFailures,
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 6:
                 return new SnapshotInfo(
@@ -204,7 +213,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     Boolean.FALSE.equals(instance.includeGlobalState()),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 7:
                 return new SnapshotInfo(
@@ -217,7 +227,8 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    randomValueOtherThan(instance.userMetadata(), SnapshotInfoTests::randomUserMetadata)
+                    randomValueOtherThan(instance.userMetadata(), SnapshotInfoTests::randomUserMetadata),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
                 );
             case 8:
                 List<String> dataStreams = randomValueOtherThan(
@@ -234,7 +245,22 @@ protected SnapshotInfo mutateInstance(SnapshotInfo instance) {
                     instance.totalShards(),
                     instance.shardFailures(),
                     instance.includeGlobalState(),
-                    instance.userMetadata()
+                    instance.userMetadata(),
+                    instance.isRemoteStoreIndexShallowCopyEnabled()
+                );
+            case 9:
+                return new SnapshotInfo(
+                    instance.snapshotId(),
+                    instance.indices(),
+                    instance.dataStreams(),
+                    instance.startTime(),
+                    instance.reason(),
+                    instance.endTime(),
+                    instance.totalShards(),
+                    instance.shardFailures(),
+                    instance.includeGlobalState(),
+                    instance.userMetadata(),
+                    Boolean.FALSE.equals(instance.isRemoteStoreIndexShallowCopyEnabled())
                 );
             default:
                 throw new IllegalArgumentException("invalid randomization case");
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotRequestsTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotRequestsTests.java
index ef93e25d0e850..a00c74f669eac 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotRequestsTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotRequestsTests.java
@@ -35,9 +35,9 @@
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
index 26e19e532b6bc..80731b378f369 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
@@ -34,10 +34,9 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionType;
 import org.opensearch.action.RequestValidators;
 import org.opensearch.action.StepListener;
@@ -56,6 +55,9 @@
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotAction;
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.delete.TransportDeleteSnapshotAction;
+import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsAction;
+import org.opensearch.action.admin.cluster.snapshots.get.GetSnapshotsRequest;
+import org.opensearch.action.admin.cluster.snapshots.get.TransportGetSnapshotsAction;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotAction;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
@@ -105,12 +107,14 @@
 import org.opensearch.client.AdminClient;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterInfo;
+import org.opensearch.cluster.ClusterInfoService;
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateListener;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.NodeConnectionsService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.SnapshotDeletionsInProgress;
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.cluster.action.index.MappingUpdatedAction;
@@ -126,6 +130,8 @@
 import org.opensearch.cluster.coordination.ElectionStrategy;
 import org.opensearch.cluster.coordination.InMemoryPersistedState;
 import org.opensearch.cluster.coordination.MockSinglePrioritizingExecutor;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.AliasValidator;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
@@ -141,50 +147,66 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.routing.allocation.AllocationService;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.command.AllocateEmptyPrimaryAllocationCommand;
 import org.opensearch.cluster.service.ClusterApplierService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.cluster.service.FakeThreadPoolMasterService;
-import org.opensearch.cluster.service.MasterService;
+import org.opensearch.cluster.service.FakeThreadPoolClusterManagerService;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.gateway.MetaStateService;
 import org.opensearch.gateway.TransportNodesListGatewayStartedShards;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexingPressureService;
+import org.opensearch.index.SegmentReplicationPressureService;
 import org.opensearch.index.analysis.AnalysisRegistry;
+import org.opensearch.index.remote.RemoteStorePressureService;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
 import org.opensearch.index.seqno.GlobalCheckpointSyncAction;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
+import org.opensearch.index.store.RemoteSegmentStoreDirectoryFactory;
+import org.opensearch.index.store.remote.filecache.FileCache;
+import org.opensearch.index.store.remote.filecache.FileCacheCleaner;
+import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
 import org.opensearch.indices.SystemIndices;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.mapper.MapperRegistry;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
 import org.opensearch.indices.recovery.PeerRecoverySourceService;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoverySettings;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationSourceService;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.ingest.IngestService;
 import org.opensearch.monitor.StatusInfo;
 import org.opensearch.node.ResponseCollectorService;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.plugins.PluginsService;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
@@ -196,11 +218,15 @@
 import org.opensearch.search.SearchService;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.search.fetch.FetchPhase;
+import org.opensearch.search.pipeline.SearchPipelineService;
 import org.opensearch.search.query.QueryPhase;
 import org.opensearch.snapshots.mockstore.MockEventuallyConsistentRepository;
+import org.opensearch.tasks.TaskResourceTrackingService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.disruption.DisruptableMockTransport;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.RemoteTransportException;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
@@ -231,12 +257,15 @@
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
+import org.mockito.Mockito;
+
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
 import static org.opensearch.action.support.ActionTestUtils.assertNoFailureListener;
 import static org.opensearch.env.Environment.PATH_HOME_SETTING;
 import static org.opensearch.monitor.StatusInfo.Status.HEALTHY;
 import static org.opensearch.node.Node.NODE_NAME_SETTING;
+import static org.opensearch.node.Node.NODE_SEARCH_CACHE_SIZE_SETTING;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.either;
@@ -248,6 +277,7 @@
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class SnapshotResiliencyTests extends OpenSearchTestCase {
 
@@ -305,7 +335,7 @@ public void verifyReposThenStopServices() {
                 blobStoreContext.forceConsistent();
             }
             BlobStoreTestUtil.assertConsistency(
-                (BlobStoreRepository) testClusterNodes.randomMasterNodeSafe().repositoriesService.repository("repo"),
+                (BlobStoreRepository) testClusterNodes.randomClusterManagerNodeSafe().repositoriesService.repository("repo"),
                 Runnable::run
             );
         } finally {
@@ -322,7 +352,7 @@ public void testSuccessfulSnapshotAndRestore() {
         final int shards = randomIntBetween(1, 10);
         final int documents = randomIntBetween(0, 100);
 
-        final TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        final TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -388,9 +418,109 @@ public void testSuccessfulSnapshotAndRestore() {
         assertNotNull(createSnapshotResponseListener.result());
         assertNotNull(restoreSnapshotResponseListener.result());
         assertTrue(documentCountVerified.get());
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
+        Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
+        assertThat(snapshotIds, hasSize(1));
+
+        final SnapshotInfo snapshotInfo = repository.getSnapshotInfo(snapshotIds.iterator().next());
+        assertEquals(SnapshotState.SUCCESS, snapshotInfo.state());
+        assertThat(snapshotInfo.indices(), containsInAnyOrder(index));
+        assertEquals(shards, snapshotInfo.successfulShards());
+        assertEquals(0, snapshotInfo.failedShards());
+    }
+
+    public void testSearchableSnapshotOverSubscription() {
+        setupTestCluster(1, 2, 2);
+
+        String repoName = "repo";
+        String snapshotName = "snapshot";
+        final String index = "test";
+        final int shards = randomIntBetween(1, 10);
+        final int documents = randomIntBetween(0, 100);
+
+        final TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
+            testClusterNodes.nodes.values().iterator().next().clusterService.state()
+        );
+
+        Map<String, FileCacheStats> nodeFileCacheStats = new HashMap<>();
+        for (TestClusterNodes.TestClusterNode node : testClusterNodes.nodes.values()) {
+            nodeFileCacheStats.put(node.node.getId(), new FileCacheStats(0, 1, 0, 0, 0, 0, 0));
+        }
+        ClusterInfo clusterInfo = new ClusterInfo(Map.of(), Map.of(), Map.of(), Map.of(), Map.of(), nodeFileCacheStats);
+        testClusterNodes.nodes.values().forEach(node -> when(node.getMockClusterInfoService().getClusterInfo()).thenReturn(clusterInfo));
+
+        final StepListener<CreateSnapshotResponse> createSnapshotResponseListener = new StepListener<>();
+
+        continueOrDie(createRepoAndIndex(repoName, index, shards), createIndexResponse -> {
+            final Runnable afterIndexing = () -> client().admin()
+                .cluster()
+                .prepareCreateSnapshot(repoName, snapshotName)
+                .setWaitForCompletion(true)
+                .execute(createSnapshotResponseListener);
+            if (documents == 0) {
+                afterIndexing.run();
+            } else {
+                final BulkRequest bulkRequest = new BulkRequest().setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
+                for (int i = 0; i < documents; ++i) {
+                    bulkRequest.add(new IndexRequest(index).source(Collections.singletonMap("foo", "bar" + i)));
+                }
+                final StepListener<BulkResponse> bulkResponseStepListener = new StepListener<>();
+                client().bulk(bulkRequest, bulkResponseStepListener);
+                continueOrDie(bulkResponseStepListener, bulkResponse -> {
+                    assertFalse("Failures in bulk response: " + bulkResponse.buildFailureMessage(), bulkResponse.hasFailures());
+                    assertEquals(documents, bulkResponse.getItems().length);
+                    afterIndexing.run();
+                });
+            }
+        });
+
+        final StepListener<AcknowledgedResponse> deleteIndexListener = new StepListener<>();
+
+        continueOrDie(
+            createSnapshotResponseListener,
+            createSnapshotResponse -> client().admin().indices().delete(new DeleteIndexRequest(index), deleteIndexListener)
+        );
+
+        final StepListener<RestoreSnapshotResponse> restoreSnapshotResponseListener = new StepListener<>();
+        continueOrDie(
+            deleteIndexListener,
+            ignored -> client().admin()
+                .cluster()
+                .restoreSnapshot(
+                    new RestoreSnapshotRequest(repoName, snapshotName).waitForCompletion(true)
+                        .storageType(RestoreSnapshotRequest.StorageType.REMOTE_SNAPSHOT),
+                    restoreSnapshotResponseListener
+                )
+        );
+
+        final AtomicBoolean exceptionVerified = new AtomicBoolean();
+
+        restoreSnapshotResponseListener.whenComplete(null, restoreSnapshotException -> {
+            Throwable throwable = restoreSnapshotException;
+            if (restoreSnapshotException instanceof RemoteTransportException) {
+                throwable = restoreSnapshotException.getCause();
+            }
+            try {
+                assertTrue(throwable instanceof SnapshotRestoreException);
+                assertTrue(
+                    throwable.getMessage()
+                        .contains(
+                            "Size of the indexes to be restored exceeds the file cache bounds. Increase the file cache capacity on the cluster nodes using "
+                                + NODE_SEARCH_CACHE_SIZE_SETTING.getKey()
+                                + " setting."
+                        )
+                );
+            } catch (SnapshotRestoreException ignored) {}
+            exceptionVerified.set(true);
+        });
+
+        runUntil(exceptionVerified::get, TimeUnit.MINUTES.toMillis(5L));
+        assertTrue(exceptionVerified.get());
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, hasSize(1));
 
@@ -403,8 +533,8 @@ public void testSuccessfulSnapshotAndRestore() {
 
     public void testSnapshotWithNodeDisconnects() {
         final int dataNodes = randomIntBetween(2, 10);
-        final int masterNodes = randomFrom(1, 3, 5);
-        setupTestCluster(masterNodes, dataNodes);
+        final int clusterManagerNodes = randomFrom(1, 3, 5);
+        setupTestCluster(clusterManagerNodes, dataNodes);
 
         String repoName = "repo";
         String snapshotName = "snapshot";
@@ -421,7 +551,7 @@ public void testSnapshotWithNodeDisconnects() {
             if (randomBoolean()) {
                 scheduleNow(() -> testClusterNodes.clearNetworkDisruptions());
             }
-            testClusterNodes.randomMasterNodeSafe().client.admin()
+            testClusterNodes.randomClusterManagerNodeSafe().client.admin()
                 .cluster()
                 .prepareCreateSnapshot(repoName, snapshotName)
                 .setPartial(partial)
@@ -434,12 +564,12 @@ public void testSnapshotWithNodeDisconnects() {
             for (int i = 0; i < randomIntBetween(0, dataNodes); ++i) {
                 scheduleNow(this::disconnectOrRestartDataNode);
             }
-            // Only disconnect master if we have more than a single master and can simulate a failover
-            final boolean disconnectedMaster = randomBoolean() && masterNodes > 1;
-            if (disconnectedMaster) {
-                scheduleNow(this::disconnectOrRestartMasterNode);
+            // Only disconnect cluster-manager if we have more than a single cluster-manager and can simulate a failover
+            final boolean disconnectedClusterManager = randomBoolean() && clusterManagerNodes > 1;
+            if (disconnectedClusterManager) {
+                scheduleNow(this::disconnectOrRestartClusterManagerNode);
             }
-            if (disconnectedMaster || randomBoolean()) {
+            if (disconnectedClusterManager || randomBoolean()) {
                 scheduleSoon(() -> testClusterNodes.clearNetworkDisruptions());
             } else if (randomBoolean()) {
                 scheduleNow(() -> testClusterNodes.clearNetworkDisruptions());
@@ -455,22 +585,22 @@ public void testSnapshotWithNodeDisconnects() {
             }
         });
 
-        runUntil(() -> testClusterNodes.randomMasterNode().map(master -> {
+        runUntil(() -> testClusterNodes.randomClusterManagerNode().map(clusterManager -> {
             if (snapshotNeverStarted.get()) {
                 return true;
             }
-            final SnapshotsInProgress snapshotsInProgress = master.clusterService.state().custom(SnapshotsInProgress.TYPE);
+            final SnapshotsInProgress snapshotsInProgress = clusterManager.clusterService.state().custom(SnapshotsInProgress.TYPE);
             return snapshotsInProgress != null && snapshotsInProgress.entries().isEmpty();
         }).orElse(false), TimeUnit.MINUTES.toMillis(1L));
 
         clearDisruptionsAndAwaitSync();
 
-        final TestClusterNodes.TestClusterNode randomMaster = testClusterNodes.randomMasterNode()
-            .orElseThrow(() -> new AssertionError("expected to find at least one active master node"));
-        SnapshotsInProgress finalSnapshotsInProgress = randomMaster.clusterService.state()
+        final TestClusterNodes.TestClusterNode randomClusterManager = testClusterNodes.randomClusterManagerNode()
+            .orElseThrow(() -> new AssertionError("expected to find at least one active cluster-manager node"));
+        SnapshotsInProgress finalSnapshotsInProgress = randomClusterManager.clusterService.state()
             .custom(SnapshotsInProgress.TYPE, SnapshotsInProgress.EMPTY);
         assertThat(finalSnapshotsInProgress.entries(), empty());
-        final Repository repository = randomMaster.repositoriesService.repository(repoName);
+        final Repository repository = randomClusterManager.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         if (snapshotNeverStarted.get()) {
             assertThat(snapshotIds, empty());
@@ -479,10 +609,10 @@ public void testSnapshotWithNodeDisconnects() {
         }
     }
 
-    public void testSnapshotDeleteWithMasterFailover() {
+    public void testSnapshotDeleteWithClusterManagerFailover() {
         final int dataNodes = randomIntBetween(2, 10);
-        final int masterNodes = randomFrom(3, 5);
-        setupTestCluster(masterNodes, dataNodes);
+        final int clusterManagerNodes = randomFrom(3, 5);
+        setupTestCluster(clusterManagerNodes, dataNodes);
 
         String repoName = "repo";
         String snapshotName = "snapshot";
@@ -493,7 +623,7 @@ public void testSnapshotDeleteWithMasterFailover() {
         final StepListener<CreateSnapshotResponse> createSnapshotResponseStepListener = new StepListener<>();
         continueOrDie(
             createRepoAndIndex(repoName, index, shards),
-            createIndexResponse -> testClusterNodes.randomMasterNodeSafe().client.admin()
+            createIndexResponse -> testClusterNodes.randomClusterManagerNodeSafe().client.admin()
                 .cluster()
                 .prepareCreateSnapshot(repoName, snapshotName)
                 .setWaitForCompletion(waitForSnapshot)
@@ -502,7 +632,7 @@ public void testSnapshotDeleteWithMasterFailover() {
 
         final AtomicBoolean snapshotDeleteResponded = new AtomicBoolean(false);
         continueOrDie(createSnapshotResponseStepListener, createSnapshotResponse -> {
-            scheduleNow(this::disconnectOrRestartMasterNode);
+            scheduleNow(this::disconnectOrRestartClusterManagerNode);
             testClusterNodes.randomDataNodeSafe().client.admin()
                 .cluster()
                 .prepareDeleteSnapshot(repoName, snapshotName)
@@ -510,10 +640,10 @@ public void testSnapshotDeleteWithMasterFailover() {
         });
 
         runUntil(
-            () -> testClusterNodes.randomMasterNode()
+            () -> testClusterNodes.randomClusterManagerNode()
                 .map(
-                    master -> snapshotDeleteResponded.get()
-                        && master.clusterService.state()
+                    clusterManager -> snapshotDeleteResponded.get()
+                        && clusterManager.clusterService.state()
                             .custom(SnapshotDeletionsInProgress.TYPE, SnapshotDeletionsInProgress.EMPTY)
                             .getEntries()
                             .isEmpty()
@@ -524,11 +654,11 @@ public void testSnapshotDeleteWithMasterFailover() {
 
         clearDisruptionsAndAwaitSync();
 
-        final TestClusterNodes.TestClusterNode randomMaster = testClusterNodes.randomMasterNode()
-            .orElseThrow(() -> new AssertionError("expected to find at least one active master node"));
-        SnapshotsInProgress finalSnapshotsInProgress = randomMaster.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        final TestClusterNodes.TestClusterNode randomClusterManager = testClusterNodes.randomClusterManagerNode()
+            .orElseThrow(() -> new AssertionError("expected to find at least one active cluster-manager node"));
+        SnapshotsInProgress finalSnapshotsInProgress = randomClusterManager.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertThat(finalSnapshotsInProgress.entries(), empty());
-        final Repository repository = randomMaster.repositoriesService.repository(repoName);
+        final Repository repository = randomClusterManager.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, hasSize(0));
     }
@@ -541,7 +671,7 @@ public void testConcurrentSnapshotCreateAndDelete() {
         final String index = "test";
         final int shards = randomIntBetween(1, 10);
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -557,12 +687,12 @@ public void testConcurrentSnapshotCreateAndDelete() {
 
         final StepListener<AcknowledgedResponse> deleteSnapshotStepListener = new StepListener<>();
 
-        masterNode.clusterService.addListener(new ClusterStateListener() {
+        clusterManagerNode.clusterService.addListener(new ClusterStateListener() {
             @Override
             public void clusterChanged(ClusterChangedEvent event) {
                 if (event.state().custom(SnapshotsInProgress.TYPE, SnapshotsInProgress.EMPTY).entries().isEmpty() == false) {
                     client().admin().cluster().prepareDeleteSnapshot(repoName, snapshotName).execute(deleteSnapshotStepListener);
-                    masterNode.clusterService.removeListener(this);
+                    clusterManagerNode.clusterService.removeListener(this);
                 }
             }
         });
@@ -586,9 +716,9 @@ public void clusterChanged(ClusterChangedEvent event) {
 
         assertNotNull(createSnapshotResponseStepListener.result());
         assertNotNull(createAnotherSnapshotResponseStepListener.result());
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, hasSize(1));
 
@@ -607,7 +737,7 @@ public void testConcurrentSnapshotCreateAndDeleteOther() {
         final String index = "test";
         final int shards = randomIntBetween(1, 10);
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -623,7 +753,6 @@ public void testConcurrentSnapshotCreateAndDeleteOther() {
         );
 
         final StepListener<CreateSnapshotResponse> createOtherSnapshotResponseStepListener = new StepListener<>();
-
         continueOrDie(
             createSnapshotResponseStepListener,
             createSnapshotResponse -> client().admin()
@@ -631,7 +760,6 @@ public void testConcurrentSnapshotCreateAndDeleteOther() {
                 .prepareCreateSnapshot(repoName, "snapshot-2")
                 .execute(createOtherSnapshotResponseStepListener)
         );
-
         final StepListener<AcknowledgedResponse> deleteSnapshotStepListener = new StepListener<>();
 
         continueOrDie(
@@ -658,13 +786,12 @@ public void testConcurrentSnapshotCreateAndDeleteOther() {
 
         deterministicTaskQueue.runAllRunnableTasks();
 
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         // We end up with two snapshots no matter if the delete worked out or not
         assertThat(snapshotIds, hasSize(2));
-
         for (SnapshotId snapshotId : snapshotIds) {
             final SnapshotInfo snapshotInfo = repository.getSnapshotInfo(snapshotId);
             assertEquals(SnapshotState.SUCCESS, snapshotInfo.state());
@@ -674,6 +801,94 @@ public void testConcurrentSnapshotCreateAndDeleteOther() {
         }
     }
 
+    public void testTransportGetSnapshotsAction() {
+        setupTestCluster(randomFrom(1, 3, 5), randomIntBetween(2, 10));
+
+        String repoName = "repo";
+        final String[] snapshotsList = { "snapshot-1" };
+        final String index = "index-1";
+        final int shards = randomIntBetween(1, 10);
+
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
+            testClusterNodes.nodes.values().iterator().next().clusterService.state()
+        );
+
+        final StepListener<CreateSnapshotResponse> createSnapshotResponseStepListener = new StepListener<>();
+        final String snapshot = snapshotsList[0];
+        continueOrDie(
+            createRepoAndIndex(repoName, index, shards),
+            createSnapshotResponse -> client().admin()
+                .cluster()
+                .prepareCreateSnapshot(repoName, snapshot)
+                .setWaitForCompletion(true)
+                .execute(createSnapshotResponseStepListener)
+        );
+
+        continueOrDie(createSnapshotResponseStepListener, createSnapshotResponse -> {
+
+            TransportAction getSnapshotsAction = clusterManagerNode.actions.get(GetSnapshotsAction.INSTANCE);
+            TransportGetSnapshotsAction transportGetSnapshotsAction = (TransportGetSnapshotsAction) getSnapshotsAction;
+            GetSnapshotsRequest repoSnapshotRequest = new GetSnapshotsRequest().repository(repoName).snapshots(snapshotsList);
+
+            transportGetSnapshotsAction.execute(null, repoSnapshotRequest, ActionListener.wrap(repoSnapshotResponse -> {
+                assertNotNull("Snapshot list should not be null", repoSnapshotResponse.getSnapshots());
+                assertThat(repoSnapshotResponse.getSnapshots(), hasSize(1));
+                List<SnapshotInfo> snapshotInfos = repoSnapshotResponse.getSnapshots();
+                SnapshotInfo snapshotInfo = snapshotInfos.get(0);
+                assertEquals(SnapshotState.SUCCESS, snapshotInfo.state());
+                assertEquals(0, snapshotInfo.failedShards());
+                assertEquals(snapshotInfo.snapshotId().getName(), snapshotsList[0]);
+            }, exception -> { throw new AssertionError(exception); }));
+        });
+    }
+
+    public void testTransportGetCurrentSnapshotsAction() {
+        setupTestCluster(randomFrom(1, 3, 5), randomIntBetween(2, 10));
+
+        String repoName = "repo";
+        final String index = "index-1";
+        final String[] snapshotsList = { GetSnapshotsRequest.CURRENT_SNAPSHOT };
+        final int shards = randomIntBetween(1, 10);
+
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
+            testClusterNodes.nodes.values().iterator().next().clusterService.state()
+        );
+
+        final StepListener<CreateSnapshotResponse> createSnapshotResponseListener = new StepListener<>();
+        clusterManagerNode.clusterService.addListener(new ClusterStateListener() {
+            @Override
+            public void clusterChanged(ClusterChangedEvent event) {
+                if (event.state().custom(SnapshotsInProgress.TYPE) != null) {
+                    TransportAction getSnapshotsAction = clusterManagerNode.actions.get(GetSnapshotsAction.INSTANCE);
+                    TransportGetSnapshotsAction transportGetSnapshotsAction = (TransportGetSnapshotsAction) getSnapshotsAction;
+                    GetSnapshotsRequest repoSnapshotRequest = new GetSnapshotsRequest().repository(repoName)
+                        .snapshots(snapshotsList)
+                        .ignoreUnavailable(false)
+                        .verbose(false);
+                    transportGetSnapshotsAction.execute(null, repoSnapshotRequest, ActionListener.wrap(repoSnapshotResponse -> {
+                        assertNotNull("Snapshot list should not be null", repoSnapshotResponse.getSnapshots());
+                        List<SnapshotInfo> snapshotInfos = repoSnapshotResponse.getSnapshots();
+                        assertThat(repoSnapshotResponse.getSnapshots(), hasSize(snapshotsList.length));
+                        for (SnapshotInfo snapshotInfo : snapshotInfos) {
+                            assertEquals(SnapshotState.IN_PROGRESS, snapshotInfo.state());
+                            assertEquals(0, snapshotInfo.failedShards());
+                            assertTrue(snapshotInfo.snapshotId().getName().contains("last-snapshot"));
+                        }
+                    }, exception -> { throw new AssertionError(exception); }));
+                    clusterManagerNode.clusterService.removeListener(this);
+                }
+            }
+        });
+        continueOrDie(
+            createRepoAndIndex(repoName, index, shards),
+            createIndexResponse -> client().admin()
+                .cluster()
+                .prepareCreateSnapshot(repoName, GetSnapshotsRequest.CURRENT_SNAPSHOT)
+                .execute(createSnapshotResponseListener)
+        );
+        deterministicTaskQueue.runAllRunnableTasks();
+    }
+
     public void testBulkSnapshotDeleteWithAbort() {
         setupTestCluster(randomFrom(1, 3, 5), randomIntBetween(2, 10));
 
@@ -682,7 +897,7 @@ public void testBulkSnapshotDeleteWithAbort() {
         final String index = "test";
         final int shards = randomIntBetween(1, 10);
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -721,9 +936,9 @@ public void testBulkSnapshotDeleteWithAbort() {
 
         deterministicTaskQueue.runAllRunnableTasks();
 
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         // No snapshots should be left in the repository
         assertThat(snapshotIds, empty());
@@ -737,7 +952,7 @@ public void testConcurrentSnapshotRestoreAndDeleteOther() {
         final String index = "test";
         final int shards = randomIntBetween(1, 10);
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -811,7 +1026,7 @@ public void testConcurrentSnapshotRestoreAndDeleteOther() {
         assertThat(deleteSnapshotStepListener.result().isAcknowledged(), is(true));
         assertThat(restoreSnapshotResponseListener.result().getRestoreInfo().failedShards(), is(0));
 
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, contains(createOtherSnapshotResponseStepListener.result().getSnapshotInfo().snapshotId()));
 
@@ -849,7 +1064,7 @@ public void testConcurrentSnapshotDeleteAndDeleteIndex() throws IOException {
         String snapshotName = "snapshot";
         final String index = "test";
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -858,7 +1073,7 @@ public void testConcurrentSnapshotDeleteAndDeleteIndex() throws IOException {
 
         final SetOnce<Index> firstIndex = new SetOnce<>();
         continueOrDie(createRepoAndIndex(repoName, index, 1), createIndexResponse -> {
-            firstIndex.set(masterNode.clusterService.state().metadata().index(index).getIndex());
+            firstIndex.set(clusterManagerNode.clusterService.state().metadata().index(index).getIndex());
             // create a few more indices to make it more likely that the subsequent index delete operation happens before snapshot
             // finalization
             final GroupedActionListener<CreateIndexResponse> listener = new GroupedActionListener<>(createIndicesListener, indices);
@@ -906,9 +1121,9 @@ public void onFailure(Exception e) {
 
         deterministicTaskQueue.runAllRunnableTasks();
 
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         final RepositoryData repositoryData = getRepositoryData(repository);
         Collection<SnapshotId> snapshotIds = repositoryData.getSnapshotIds();
         assertThat(snapshotIds, hasSize(1));
@@ -943,7 +1158,7 @@ public void testConcurrentDeletes() {
         final String index = "test";
         final int shards = randomIntBetween(1, 10);
 
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -989,9 +1204,10 @@ public void testConcurrentDeletes() {
 
         deterministicTaskQueue.runAllRunnableTasks();
 
-        SnapshotDeletionsInProgress deletionsInProgress = masterNode.clusterService.state().custom(SnapshotDeletionsInProgress.TYPE);
+        SnapshotDeletionsInProgress deletionsInProgress = clusterManagerNode.clusterService.state()
+            .custom(SnapshotDeletionsInProgress.TYPE);
         assertFalse(deletionsInProgress.hasDeletionsInProgress());
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         final RepositoryData repositoryData = getRepositoryData(repository);
         Collection<SnapshotId> snapshotIds = repositoryData.getSnapshotIds();
         // We end up with no snapshots since at least one of the deletes worked out
@@ -1002,12 +1218,12 @@ public void testConcurrentDeletes() {
     }
 
     /**
-     * Simulates concurrent restarts of data and master nodes as well as relocating a primary shard, while starting and subsequently
+     * Simulates concurrent restarts of data and cluster-manager nodes as well as relocating a primary shard, while starting and subsequently
      * deleting a snapshot.
      */
     public void testSnapshotPrimaryRelocations() {
-        final int masterNodeCount = randomFrom(1, 3, 5);
-        setupTestCluster(masterNodeCount, randomIntBetween(2, 5));
+        final int clusterManagerNodeCount = randomFrom(1, 3, 5);
+        setupTestCluster(clusterManagerNodeCount, randomIntBetween(2, 5));
 
         String repoName = "repo";
         String snapshotName = "snapshot";
@@ -1015,11 +1231,11 @@ public void testSnapshotPrimaryRelocations() {
 
         final int shards = randomIntBetween(1, 5);
 
-        final TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        final TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
         final AtomicBoolean createdSnapshot = new AtomicBoolean();
-        final AdminClient masterAdminClient = masterNode.client.admin();
+        final AdminClient clusterManagerAdminClient = clusterManagerNode.client.admin();
 
         final StepListener<ClusterStateResponse> clusterStateResponseStepListener = new StepListener<>();
 
@@ -1037,15 +1253,15 @@ public void testSnapshotPrimaryRelocations() {
                 @Override
                 public void run() {
                     final StepListener<ClusterStateResponse> updatedClusterStateResponseStepListener = new StepListener<>();
-                    masterAdminClient.cluster().state(new ClusterStateRequest(), updatedClusterStateResponseStepListener);
+                    clusterManagerAdminClient.cluster().state(new ClusterStateRequest(), updatedClusterStateResponseStepListener);
                     continueOrDie(updatedClusterStateResponseStepListener, updatedClusterState -> {
                         final ShardRouting shardRouting = updatedClusterState.getState()
                             .routingTable()
                             .shardRoutingTable(shardToRelocate.shardId())
                             .primaryShard();
                         if (shardRouting.unassigned() && shardRouting.unassignedInfo().getReason() == UnassignedInfo.Reason.NODE_LEFT) {
-                            if (masterNodeCount > 1) {
-                                scheduleNow(() -> testClusterNodes.stopNode(masterNode));
+                            if (clusterManagerNodeCount > 1) {
+                                scheduleNow(() -> testClusterNodes.stopNode(clusterManagerNode));
                             }
                             testClusterNodes.randomDataNodeSafe().client.admin()
                                 .cluster()
@@ -1057,7 +1273,7 @@ public void run() {
                                         .deleteSnapshot(new DeleteSnapshotRequest(repoName, snapshotName), noopListener());
                                 }));
                             scheduleNow(
-                                () -> testClusterNodes.randomMasterNodeSafe().client.admin()
+                                () -> testClusterNodes.randomClusterManagerNodeSafe().client.admin()
                                     .cluster()
                                     .reroute(
                                         new ClusterRerouteRequest().add(
@@ -1079,11 +1295,11 @@ public void run() {
             });
         });
 
-        runUntil(() -> testClusterNodes.randomMasterNode().map(master -> {
+        runUntil(() -> testClusterNodes.randomClusterManagerNode().map(clusterManager -> {
             if (createdSnapshot.get() == false) {
                 return false;
             }
-            return master.clusterService.state().custom(SnapshotsInProgress.TYPE, SnapshotsInProgress.EMPTY).entries().isEmpty();
+            return clusterManager.clusterService.state().custom(SnapshotsInProgress.TYPE, SnapshotsInProgress.EMPTY).entries().isEmpty();
         }).orElse(false), TimeUnit.MINUTES.toMillis(1L));
 
         clearDisruptionsAndAwaitSync();
@@ -1095,7 +1311,7 @@ public void run() {
                 .entries(),
             empty()
         );
-        final Repository repository = testClusterNodes.randomMasterNodeSafe().repositoriesService.repository(repoName);
+        final Repository repository = testClusterNodes.randomClusterManagerNodeSafe().repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, either(hasSize(1)).or(hasSize(0)));
     }
@@ -1109,7 +1325,7 @@ public void testSuccessfulSnapshotWithConcurrentDynamicMappingUpdates() {
 
         final int shards = randomIntBetween(1, 10);
         final int documents = randomIntBetween(2, 100);
-        TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -1170,7 +1386,7 @@ public void testSuccessfulSnapshotWithConcurrentDynamicMappingUpdates() {
                 "Documents were restored but the restored index mapping was older than some documents and misses some of their fields",
                 (int) hitCount,
                 lessThanOrEqualTo(
-                    ((Map<?, ?>) masterNode.clusterService.state()
+                    ((Map<?, ?>) clusterManagerNode.clusterService.state()
                         .metadata()
                         .index(restoredIndex)
                         .mapping()
@@ -1185,9 +1401,9 @@ public void testSuccessfulSnapshotWithConcurrentDynamicMappingUpdates() {
 
         assertNotNull(createSnapshotResponseStepListener.result());
         assertNotNull(restoreSnapshotResponseStepListener.result());
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, hasSize(1));
 
@@ -1209,7 +1425,7 @@ public void testRunConcurrentSnapshots() {
         final int shards = randomIntBetween(1, 10);
         final int documents = randomIntBetween(1, 100);
 
-        final TestClusterNodes.TestClusterNode masterNode = testClusterNodes.currentMaster(
+        final TestClusterNodes.TestClusterNode clusterManagerNode = testClusterNodes.currentClusterManager(
             testClusterNodes.nodes.values().iterator().next().clusterService.state()
         );
 
@@ -1252,9 +1468,9 @@ public void testRunConcurrentSnapshots() {
         });
 
         runUntil(() -> doneIndexing.get() && doneSnapshotting.get(), TimeUnit.MINUTES.toMillis(5L));
-        SnapshotsInProgress finalSnapshotsInProgress = masterNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
+        SnapshotsInProgress finalSnapshotsInProgress = clusterManagerNode.clusterService.state().custom(SnapshotsInProgress.TYPE);
         assertFalse(finalSnapshotsInProgress.entries().stream().anyMatch(entry -> entry.state().completed() == false));
-        final Repository repository = masterNode.repositoriesService.repository(repoName);
+        final Repository repository = clusterManagerNode.repositoriesService.repository(repoName);
         Collection<SnapshotId> snapshotIds = getRepositoryData(repository).getSnapshotIds();
         assertThat(snapshotIds, hasSize(snapshotNames.size()));
 
@@ -1313,12 +1529,12 @@ private void disconnectOrRestartDataNode() {
         }
     }
 
-    private void disconnectOrRestartMasterNode() {
-        testClusterNodes.randomMasterNode().ifPresent(masterNode -> {
+    private void disconnectOrRestartClusterManagerNode() {
+        testClusterNodes.randomClusterManagerNode().ifPresent(clusterManagerNode -> {
             if (randomBoolean()) {
-                testClusterNodes.disconnectNode(masterNode);
+                testClusterNodes.disconnectNode(clusterManagerNode);
             } else {
-                masterNode.restart();
+                clusterManagerNode.restart();
             }
         });
     }
@@ -1339,13 +1555,13 @@ private void startCluster() {
             testClusterNodes.nodes.values()
                 .stream()
                 .map(n -> n.node)
-                .filter(DiscoveryNode::isMasterNode)
+                .filter(DiscoveryNode::isClusterManagerNode)
                 .map(DiscoveryNode::getId)
                 .collect(Collectors.toSet())
         );
         testClusterNodes.nodes.values()
             .stream()
-            .filter(n -> n.node.isMasterNode())
+            .filter(n -> n.node.isClusterManagerNode())
             .forEach(testClusterNode -> testClusterNode.coordinator.setInitialConfiguration(votingConfiguration));
         // Connect all nodes to each other
         testClusterNodes.nodes.values()
@@ -1373,12 +1589,15 @@ private void stabilize() {
                 .stream()
                 .map(node -> node.clusterService.state())
                 .collect(Collectors.toList());
-            final Set<String> masterNodeIds = clusterStates.stream()
-                .map(clusterState -> clusterState.nodes().getMasterNodeId())
+            final Set<String> clusterManagerNodeIds = clusterStates.stream()
+                .map(clusterState -> clusterState.nodes().getClusterManagerNodeId())
                 .collect(Collectors.toSet());
             final Set<Long> terms = clusterStates.stream().map(ClusterState::term).collect(Collectors.toSet());
             final List<Long> versions = clusterStates.stream().map(ClusterState::version).distinct().collect(Collectors.toList());
-            return versions.size() == 1 && masterNodeIds.size() == 1 && masterNodeIds.contains(null) == false && terms.size() == 1;
+            return versions.size() == 1
+                && clusterManagerNodeIds.size() == 1
+                && clusterManagerNodeIds.contains(null) == false
+                && terms.size() == 1;
         }, TimeUnit.MINUTES.toMillis(1L));
     }
 
@@ -1394,8 +1613,13 @@ private void runUntil(Supplier<Boolean> fulfilled, long timeout) {
         fail("Condition wasn't fulfilled.");
     }
 
-    private void setupTestCluster(int masterNodes, int dataNodes) {
-        testClusterNodes = new TestClusterNodes(masterNodes, dataNodes);
+    private void setupTestCluster(int clusterManagerNodes, int dataNodes) {
+        testClusterNodes = new TestClusterNodes(clusterManagerNodes, dataNodes);
+        startCluster();
+    }
+
+    private void setupTestCluster(int clusterManagerNodes, int dataNodes, int searchNodes) {
+        testClusterNodes = new TestClusterNodes(clusterManagerNodes, dataNodes, searchNodes);
         startCluster();
     }
 
@@ -1449,6 +1673,7 @@ private Environment createEnvironment(String nodeName) {
                     ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(),
                     ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING.get(Settings.EMPTY)
                 )
+                .put(FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING.getKey(), 5)
                 .put(MappingUpdatedAction.INDICES_MAX_IN_FLIGHT_UPDATES_SETTING.getKey(), 1000) // o.w. some tests might block
                 .build()
         );
@@ -1471,11 +1696,15 @@ private final class TestClusterNodes {
          */
         private final Set<String> disconnectedNodes = new HashSet<>();
 
-        TestClusterNodes(int masterNodes, int dataNodes) {
-            for (int i = 0; i < masterNodes; ++i) {
+        TestClusterNodes(int clusterManagerNodes, int dataNodes) {
+            this(clusterManagerNodes, dataNodes, 0);
+        }
+
+        TestClusterNodes(int clusterManagerNodes, int dataNodes, int searchNodes) {
+            for (int i = 0; i < clusterManagerNodes; ++i) {
                 nodes.computeIfAbsent("node" + i, nodeName -> {
                     try {
-                        return newMasterNode(nodeName);
+                        return newClusterManagerNode(nodeName);
                     } catch (IOException e) {
                         throw new AssertionError(e);
                     }
@@ -1490,6 +1719,15 @@ private final class TestClusterNodes {
                     }
                 });
             }
+            for (int i = 0; i < searchNodes; ++i) {
+                nodes.computeIfAbsent("search-node" + i, nodeName -> {
+                    try {
+                        return newSearchNode(nodeName);
+                    } catch (IOException e) {
+                        throw new AssertionError(e);
+                    }
+                });
+            }
         }
 
         public TestClusterNode nodeById(final String nodeId) {
@@ -1500,7 +1738,7 @@ public TestClusterNode nodeById(final String nodeId) {
                 .orElseThrow(() -> new AssertionError("Could not find node by id [" + nodeId + ']'));
         }
 
-        private TestClusterNode newMasterNode(String nodeName) throws IOException {
+        private TestClusterNode newClusterManagerNode(String nodeName) throws IOException {
             return newNode(nodeName, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
         }
 
@@ -1508,6 +1746,10 @@ private TestClusterNode newDataNode(String nodeName) throws IOException {
             return newNode(nodeName, DiscoveryNodeRole.DATA_ROLE);
         }
 
+        private TestClusterNode newSearchNode(String nodeName) throws IOException {
+            return newNode(nodeName, DiscoveryNodeRole.SEARCH_ROLE);
+        }
+
         private TestClusterNode newNode(String nodeName, DiscoveryNodeRole role) throws IOException {
             return new TestClusterNode(
                 new DiscoveryNode(
@@ -1521,19 +1763,21 @@ private TestClusterNode newNode(String nodeName, DiscoveryNodeRole role) throws
             );
         }
 
-        public TestClusterNode randomMasterNodeSafe() {
-            return randomMasterNode().orElseThrow(() -> new AssertionError("Expected to find at least one connected master node"));
+        public TestClusterNode randomClusterManagerNodeSafe() {
+            return randomClusterManagerNode().orElseThrow(
+                () -> new AssertionError("Expected to find at least one connected cluster-manager node")
+            );
         }
 
-        public Optional<TestClusterNode> randomMasterNode() {
+        public Optional<TestClusterNode> randomClusterManagerNode() {
             // Select from sorted list of data-nodes here to not have deterministic behaviour
-            final List<TestClusterNode> masterNodes = testClusterNodes.nodes.values()
+            final List<TestClusterNode> clusterManagerNodes = testClusterNodes.nodes.values()
                 .stream()
-                .filter(n -> n.node.isMasterNode())
+                .filter(n -> n.node.isClusterManagerNode())
                 .filter(n -> disconnectedNodes.contains(n.node.getName()) == false)
                 .sorted(Comparator.comparing(n -> n.node.getName()))
                 .collect(Collectors.toList());
-            return masterNodes.isEmpty() ? Optional.empty() : Optional.of(randomFrom(masterNodes));
+            return clusterManagerNodes.isEmpty() ? Optional.empty() : Optional.of(randomFrom(clusterManagerNodes));
         }
 
         public void stopNode(TestClusterNode node) {
@@ -1595,19 +1839,18 @@ public DiscoveryNodes discoveryNodes() {
         }
 
         /**
-         * Returns the {@link TestClusterNode} for the master node in the given {@link ClusterState}.
+         * Returns the {@link TestClusterNode} for the cluster-manager node in the given {@link ClusterState}.
          * @param state ClusterState
-         * @return Master Node
+         * @return Cluster Manager Node
          */
-        public TestClusterNode currentMaster(ClusterState state) {
-            TestClusterNode master = nodes.get(state.nodes().getMasterNode().getName());
-            assertNotNull(master);
-            assertTrue(master.node.isMasterNode());
-            return master;
+        public TestClusterNode currentClusterManager(ClusterState state) {
+            TestClusterNode clusterManager = nodes.get(state.nodes().getClusterManagerNode().getName());
+            assertNotNull(clusterManager);
+            assertTrue(clusterManager.node.isClusterManagerNode());
+            return clusterManager;
         }
 
         private final class TestClusterNode {
-
             private final Logger logger = LogManager.getLogger(TestClusterNode.class);
 
             private final NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(
@@ -1635,7 +1878,7 @@ private final class TestClusterNode {
 
             private final DiscoveryNode node;
 
-            private final MasterService masterService;
+            private final ClusterManagerService clusterManagerService;
 
             private final AllocationService allocationService;
 
@@ -1649,19 +1892,29 @@ private final class TestClusterNode {
 
             private final ThreadPool threadPool;
 
+            private final ClusterInfoService clusterInfoService;
+
             private Coordinator coordinator;
+            private RemoteStoreNodeService remoteStoreNodeService;
+
+            private Map<ActionType, TransportAction> actions = new HashMap<>();
 
             TestClusterNode(DiscoveryNode node) throws IOException {
                 this.node = node;
                 final Environment environment = createEnvironment(node.getName());
                 threadPool = deterministicTaskQueue.getThreadPool(runnable -> CoordinatorTests.onNodeLog(node, runnable));
-                masterService = new FakeThreadPoolMasterService(node.getName(), "test", threadPool, deterministicTaskQueue::scheduleNow);
+                clusterManagerService = new FakeThreadPoolClusterManagerService(
+                    node.getName(),
+                    "test",
+                    threadPool,
+                    deterministicTaskQueue::scheduleNow
+                );
                 final Settings settings = environment.settings();
                 final ClusterSettings clusterSettings = new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
                 clusterService = new ClusterService(
                     settings,
                     clusterSettings,
-                    masterService,
+                    clusterManagerService,
                     new ClusterApplierService(node.getName(), settings, clusterSettings, threadPool) {
                         @Override
                         protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
@@ -1734,10 +1987,12 @@ public void onFailure(final Exception e) {
                             return actualHandler;
                         }
                     }
-                }, a -> node, null, emptySet());
+                }, a -> node, null, emptySet(), NoopTracer.INSTANCE);
                 final IndexNameExpressionResolver indexNameExpressionResolver = new IndexNameExpressionResolver(
                     new ThreadContext(Settings.EMPTY)
                 );
+                transportService.getTaskManager()
+                    .setTaskResourceTrackingService(new TaskResourceTrackingService(settings, clusterSettings, threadPool));
                 repositoriesService = new RepositoriesService(
                     settings,
                     clusterService,
@@ -1746,6 +2001,7 @@ public void onFailure(final Exception e) {
                     emptyMap(),
                     threadPool
                 );
+                remoteStoreNodeService = new RemoteStoreNodeService(new SetOnce<>(repositoriesService)::get, threadPool);
                 final ActionFilters actionFilters = new ActionFilters(emptySet());
                 snapshotsService = new SnapshotsService(
                     settings,
@@ -1759,6 +2015,7 @@ public void onFailure(final Exception e) {
                 final NamedXContentRegistry namedXContentRegistry = new NamedXContentRegistry(Collections.emptyList());
                 final ScriptService scriptService = new ScriptService(settings, emptyMap(), emptyMap());
                 client = new NodeClient(settings, threadPool);
+                clusterInfoService = Mockito.mock(ClusterInfoService.class);
                 final SetOnce<RerouteService> rerouteServiceSetOnce = new SetOnce<>();
                 final SnapshotsInfoService snapshotsInfoService = new InternalSnapshotsInfoService(
                     settings,
@@ -1775,6 +2032,9 @@ public void onFailure(final Exception e) {
                 );
                 final BigArrays bigArrays = new BigArrays(new PageCacheRecycler(settings), null, "test");
                 final MapperRegistry mapperRegistry = new IndicesModule(Collections.emptyList()).getMapperRegistry();
+                final SetOnce<RepositoriesService> repositoriesServiceReference = new SetOnce<>();
+                repositoriesServiceReference.set(repositoriesService);
+                FileCacheCleaner fileCacheCleaner = new FileCacheCleaner(nodeEnv, null);
                 indicesService = new IndicesService(
                     settings,
                     mock(PluginsService.class),
@@ -1806,7 +2066,12 @@ public void onFailure(final Exception e) {
                     Collections.emptyList(),
                     emptyMap(),
                     null,
-                    emptyMap()
+                    emptyMap(),
+                    new RemoteSegmentStoreDirectoryFactory(() -> repositoriesService, threadPool, DefaultRecoverySettings.INSTANCE),
+                    repositoriesServiceReference::get,
+                    fileCacheCleaner,
+                    null,
+                    new RemoteStoreStatsTrackerFactory(clusterService, settings)
                 );
                 final RecoverySettings recoverySettings = new RecoverySettings(settings, clusterSettings);
                 snapshotShardsService = new SnapshotShardsService(
@@ -1831,6 +2096,15 @@ public void onFailure(final Exception e) {
                     clusterService,
                     threadPool,
                     new PeerRecoveryTargetService(threadPool, transportService, recoverySettings, clusterService),
+                    new SegmentReplicationTargetService(
+                        threadPool,
+                        recoverySettings,
+                        transportService,
+                        new SegmentReplicationSourceFactory(transportService, recoverySettings, clusterService),
+                        indicesService,
+                        clusterService
+                    ),
+                    mock(SegmentReplicationSourceService.class),
                     shardStateAction,
                     new NodeMappingRefreshAction(transportService, metadataMappingService),
                     repositoriesService,
@@ -1860,10 +2134,13 @@ public void onFailure(final Exception e) {
                         shardStateAction,
                         actionFilters
                     ),
-                    RetentionLeaseSyncer.EMPTY
+                    RetentionLeaseSyncer.EMPTY,
+                    SegmentReplicationCheckpointPublisher.EMPTY,
+                    mock(RemoteStoreStatsTrackerFactory.class)
                 );
-                Map<ActionType, TransportAction> actions = new HashMap<>();
-                final ShardLimitValidator shardLimitValidator = new ShardLimitValidator(settings, clusterService);
+
+                final SystemIndices systemIndices = new SystemIndices(emptyMap());
+                final ShardLimitValidator shardLimitValidator = new ShardLimitValidator(settings, clusterService, systemIndices);
                 final MetadataCreateIndexService metadataCreateIndexService = new MetadataCreateIndexService(
                     settings,
                     clusterService,
@@ -1875,8 +2152,9 @@ public void onFailure(final Exception e) {
                     indexScopedSettings,
                     threadPool,
                     namedXContentRegistry,
-                    new SystemIndices(emptyMap()),
-                    false
+                    systemIndices,
+                    false,
+                    new AwarenessReplicaBalance(Settings.EMPTY, clusterService.getClusterSettings())
                 );
                 actions.put(
                     CreateIndexAction.INSTANCE,
@@ -1902,6 +2180,14 @@ public void onFailure(final Exception e) {
                     new UpdateHelper(scriptService),
                     actionFilters,
                     new IndexingPressureService(settings, clusterService),
+                    new SegmentReplicationPressureService(
+                        settings,
+                        clusterService,
+                        mock(IndicesService.class),
+                        mock(ShardStateAction.class),
+                        mock(ThreadPool.class)
+                    ),
+                    mock(RemoteStorePressureService.class),
                     new SystemIndices(emptyMap())
                 );
                 actions.put(
@@ -1925,6 +2211,7 @@ public void onFailure(final Exception e) {
                         indexNameExpressionResolver,
                         new AutoCreateIndex(settings, clusterSettings, indexNameExpressionResolver, new SystemIndices(emptyMap())),
                         new IndexingPressureService(settings, clusterService),
+                        mock(IndicesService.class),
                         new SystemIndices(emptyMap())
                     )
                 );
@@ -1941,8 +2228,9 @@ public void onFailure(final Exception e) {
                         new SystemIndices(emptyMap()),
                         null
                     ),
-                    clusterSettings,
-                    shardLimitValidator
+                    shardLimitValidator,
+                    indicesService,
+                    clusterInfoService::getClusterInfo
                 );
                 actions.put(
                     PutMappingAction.INSTANCE,
@@ -2001,7 +2289,19 @@ public void onFailure(final Exception e) {
                         clusterService,
                         actionFilters,
                         indexNameExpressionResolver,
-                        namedWriteableRegistry
+                        namedWriteableRegistry,
+                        new SearchPipelineService(
+                            clusterService,
+                            threadPool,
+                            environment,
+                            scriptService,
+                            new AnalysisModule(environment, Collections.emptyList()).getAnalysisRegistry(),
+                            namedXContentRegistry,
+                            namedWriteableRegistry,
+                            List.of(),
+                            client
+                        ),
+                        null
                     )
                 );
                 actions.put(
@@ -2072,6 +2372,17 @@ public void onFailure(final Exception e) {
                         indexNameExpressionResolver
                     )
                 );
+                actions.put(
+                    GetSnapshotsAction.INSTANCE,
+                    new TransportGetSnapshotsAction(
+                        transportService,
+                        clusterService,
+                        threadPool,
+                        repositoriesService,
+                        actionFilters,
+                        indexNameExpressionResolver
+                    )
+                );
                 actions.put(
                     ClusterStateAction.INSTANCE,
                     new TransportClusterStateAction(
@@ -2113,8 +2424,10 @@ public void onFailure(final Exception e) {
                         indexNameExpressionResolver
                     )
                 );
+                DynamicActionRegistry dynamicActionRegistry = new DynamicActionRegistry();
+                dynamicActionRegistry.registerUnmodifiableActionMap(actions);
                 client.initialize(
-                    actions,
+                    dynamicActionRegistry,
                     () -> clusterService.localNode().getId(),
                     transportService.getRemoteClusterService(),
                     new NamedWriteableRegistry(Collections.emptyList())
@@ -2142,6 +2455,10 @@ protected void assertSnapshotOrGenericThread() {
                 }
             }
 
+            public ClusterInfoService getMockClusterInfoService() {
+                return clusterInfoService;
+            }
+
             public void restart() {
                 testClusterNodes.disconnectNode(this);
                 final ClusterState oldState = this.clusterService.state();
@@ -2182,6 +2499,8 @@ public void start(ClusterState initialState) {
                     initialState.term(),
                     stateForNode(initialState, node)
                 );
+                final PersistedStateRegistry persistedStateRegistry = persistedStateRegistry();
+                persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, persistedState);
                 coordinator = new Coordinator(
                     node.getName(),
                     clusterService.getSettings(),
@@ -2189,11 +2508,11 @@ public void start(ClusterState initialState) {
                     transportService,
                     namedWriteableRegistry,
                     allocationService,
-                    masterService,
+                    clusterManagerService,
                     () -> persistedState,
                     hostsResolver -> nodes.values()
                         .stream()
-                        .filter(n -> n.node.isMasterNode())
+                        .filter(n -> n.node.isClusterManagerNode())
                         .map(n -> n.node.getAddress())
                         .collect(Collectors.toList()),
                     clusterService.getClusterApplierService(),
@@ -2201,9 +2520,11 @@ public void start(ClusterState initialState) {
                     random(),
                     rerouteService,
                     ElectionStrategy.DEFAULT_INSTANCE,
-                    () -> new StatusInfo(HEALTHY, "healthy-info")
+                    () -> new StatusInfo(HEALTHY, "healthy-info"),
+                    persistedStateRegistry,
+                    remoteStoreNodeService
                 );
-                masterService.setClusterStatePublisher(coordinator);
+                clusterManagerService.setClusterStatePublisher(coordinator);
                 coordinator.start();
                 clusterService.getClusterApplierService().setNodeConnectionsService(nodeConnectionsService);
                 nodeConnectionsService.start();
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotShardsServiceTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotShardsServiceTests.java
index 39f13ecbbbee3..21a24166a4571 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotShardsServiceTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotShardsServiceTests.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.cluster.SnapshotsInProgress;
 import org.opensearch.common.UUIDs;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.EqualsHashCodeTestUtils;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotUtilsTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotUtilsTests.java
index 489294fd53bd4..14e711e03a345 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotUtilsTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotUtilsTests.java
@@ -31,12 +31,21 @@
 
 package org.opensearch.snapshots;
 
+import org.opensearch.Version;
 import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.IndexSettings;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 
 public class SnapshotUtilsTests extends OpenSearchTestCase {
@@ -56,6 +65,9 @@ public void testIndexNameFiltering() {
         assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "-ba*" }, new String[] { "foo" });
         assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "+ba*" }, new String[] { "bar", "baz" });
         assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "+bar", "+foo" }, new String[] { "bar", "foo" });
+        assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "-bar", "b*" }, new String[] { "baz" });
+        assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "b*", "-bar" }, new String[] { "baz" });
+        assertIndexNameFiltering(new String[] { "foo", "bar", "baz" }, new String[] { "-bar", "-baz" }, new String[] { "foo" });
         assertIndexNameFiltering(
             new String[] { "foo", "bar", "baz" },
             new String[] { "zzz", "bar" },
@@ -85,4 +97,39 @@ private void assertIndexNameFiltering(String[] indices, String[] filter, Indices
         List<String> actual = SnapshotUtils.filterIndices(indicesList, filter, indicesOptions);
         assertThat(actual, containsInAnyOrder(expected));
     }
+
+    public void testValidateSnapshotsBackingAnyIndex() {
+        final String repoName = "test-repo";
+        final SnapshotId snapshotId1 = new SnapshotId("testSnapshot1", "uuid1");
+        final SnapshotId snapshotId2 = new SnapshotId("testSnapshot2", "uuid2");
+        SnapshotUtils.validateSnapshotsBackingAnyIndex(getIndexMetadata(snapshotId1, repoName), List.of(snapshotId2), repoName);
+    }
+
+    public void testValidateSnapshotsBackingAnyIndexThrowsException() {
+        final String repoName = "test-repo";
+        final SnapshotId snapshotId1 = new SnapshotId("testSnapshot1", "uuid1");
+        expectThrows(
+            SnapshotInUseDeletionException.class,
+            () -> SnapshotUtils.validateSnapshotsBackingAnyIndex(getIndexMetadata(snapshotId1, repoName), List.of(snapshotId1), repoName)
+        );
+    }
+
+    private static Map<String, IndexMetadata> getIndexMetadata(SnapshotId snapshotId, String repoName) {
+        final String index = "test-index";
+        Snapshot snapshot = new Snapshot(repoName, snapshotId);
+        final Metadata.Builder builder = Metadata.builder();
+        builder.put(createIndexMetadata(new Index(index, "uuid"), snapshot), true);
+        return builder.build().getIndices();
+    }
+
+    private static IndexMetadata createIndexMetadata(final Index index, Snapshot snapshot) {
+        final Settings settings = Settings.builder()
+            .put(SETTING_VERSION_CREATED, Version.CURRENT.id)
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_REPOSITORY.getKey(), snapshot.getRepository())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_ID_UUID.getKey(), snapshot.getSnapshotId().getUUID())
+            .put(IndexSettings.SEARCHABLE_SNAPSHOT_ID_NAME.getKey(), snapshot.getSnapshotId().getName())
+            .build();
+        return IndexMetadata.builder(index.getName()).settings(settings).numberOfShards(1).numberOfReplicas(0).build();
+    }
 }
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotsInProgressSerializationTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotsInProgressSerializationTests.java
index dc5d869c2f6a2..8fd1f44286094 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotsInProgressSerializationTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotsInProgressSerializationTests.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.snapshots;
 
+import org.opensearch.Version;
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.ClusterState.Custom;
 import org.opensearch.cluster.Diff;
@@ -39,20 +40,28 @@
 import org.opensearch.cluster.SnapshotsInProgress.Entry;
 import org.opensearch.cluster.SnapshotsInProgress.ShardState;
 import org.opensearch.cluster.SnapshotsInProgress.State;
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.test.AbstractDiffableWireSerializationTestCase;
 import org.opensearch.test.VersionUtils;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
+import static org.opensearch.test.VersionUtils.randomVersion;
+
 public class SnapshotsInProgressSerializationTests extends AbstractDiffableWireSerializationTestCase<Custom> {
 
     @Override
@@ -69,6 +78,7 @@ private Entry randomSnapshot() {
         Snapshot snapshot = new Snapshot(randomAlphaOfLength(10), new SnapshotId(randomAlphaOfLength(10), randomAlphaOfLength(10)));
         boolean includeGlobalState = randomBoolean();
         boolean partial = randomBoolean();
+        boolean remoteStoreIndexShallowCopy = randomBoolean();
         int numberOfIndices = randomIntBetween(0, 10);
         List<IndexId> indices = new ArrayList<>();
         for (int i = 0; i < numberOfIndices; i++) {
@@ -76,7 +86,7 @@ private Entry randomSnapshot() {
         }
         long startTime = randomLong();
         long repositoryStateId = randomLong();
-        ImmutableOpenMap.Builder<ShardId, SnapshotsInProgress.ShardSnapshotStatus> builder = ImmutableOpenMap.builder();
+        Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> builder = new HashMap<>();
         final List<Index> esIndices = indices.stream()
             .map(i -> new Index(i.getName(), randomAlphaOfLength(10)))
             .collect(Collectors.toList());
@@ -100,7 +110,7 @@ private Entry randomSnapshot() {
                 );
             }
         }
-        ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards = builder.build();
+        Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards = Collections.unmodifiableMap(builder);
         return new Entry(
             snapshot,
             includeGlobalState,
@@ -113,7 +123,8 @@ private Entry randomSnapshot() {
             shards,
             null,
             SnapshotInfoTests.randomUserMetadata(),
-            VersionUtils.randomVersion(random())
+            VersionUtils.randomVersion(random()),
+            remoteStoreIndexShallowCopy
         );
     }
 
@@ -172,9 +183,67 @@ protected Custom mutateInstance(Custom instance) {
         return SnapshotsInProgress.of(entries);
     }
 
-    public static State randomState(ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards) {
+    public void testSerDeRemoteStoreIndexShallowCopy() throws IOException {
+        SnapshotsInProgress.Entry entry = new SnapshotsInProgress.Entry(
+            new Snapshot(randomName("repo"), new SnapshotId(randomName("snap"), UUIDs.randomBase64UUID())),
+            randomBoolean(),
+            randomBoolean(),
+            SnapshotsInProgressSerializationTests.randomState(Map.of()),
+            Collections.emptyList(),
+            Collections.emptyList(),
+            Math.abs(randomLong()),
+            randomIntBetween(0, 1000),
+            Map.of(),
+            null,
+            SnapshotInfoTests.randomUserMetadata(),
+            randomVersion(random()),
+            true
+        );
+        final List<SnapshotsInProgress.Entry> newEntries = new ArrayList<>();
+        newEntries.add(entry);
+        SnapshotsInProgress snapshotsInProgress = SnapshotsInProgress.of(newEntries);
+
+        SnapshotsInProgress actualSnapshotsInProgress;
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            snapshotsInProgress.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                in.setVersion(Version.V_2_7_0);
+                actualSnapshotsInProgress = new SnapshotsInProgress(in);
+                assert in.available() != 0;
+                for (Entry curr_entry : actualSnapshotsInProgress.entries()) {
+                    assert (curr_entry.remoteStoreIndexShallowCopy() == false);
+                }
+            }
+            try (StreamInput in = out.bytes().streamInput()) {
+                in.setVersion(Version.V_2_9_0);
+                actualSnapshotsInProgress = new SnapshotsInProgress(in);
+                assert in.available() == 0;
+                for (Entry curr_entry : actualSnapshotsInProgress.entries()) {
+                    assert (curr_entry.remoteStoreIndexShallowCopy() == true);
+                }
+            }
+        }
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            out.setVersion(Version.V_2_7_0);
+            snapshotsInProgress.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                in.setVersion(Version.V_2_7_0);
+                actualSnapshotsInProgress = new SnapshotsInProgress(in);
+                assert in.available() == 0;
+                for (Entry curr_entry : actualSnapshotsInProgress.entries()) {
+                    assert (curr_entry.remoteStoreIndexShallowCopy() == false);
+                }
+            }
+        }
+    }
+
+    public static State randomState(final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards) {
         return SnapshotsInProgress.completed(shards.values())
             ? randomFrom(State.SUCCESS, State.FAILED)
             : randomFrom(State.STARTED, State.INIT, State.ABORTED);
     }
+
+    private String randomName(String prefix) {
+        return prefix + UUIDs.randomBase64UUID(random());
+    }
 }
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotsServiceTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotsServiceTests.java
index 16fc7467d099b..1652ba29b8fa7 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotsServiceTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotsServiceTests.java
@@ -44,10 +44,9 @@
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoryShardId;
 import org.opensearch.test.OpenSearchTestCase;
@@ -55,6 +54,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
@@ -66,7 +66,7 @@ public class SnapshotsServiceTests extends OpenSearchTestCase {
     public void testNoopShardStateUpdates() throws Exception {
         final String repoName = "test-repo";
         final Snapshot snapshot = snapshot(repoName, "snapshot-1");
-        final SnapshotsInProgress.Entry snapshotNoShards = snapshotEntry(snapshot, Collections.emptyList(), ImmutableOpenMap.of());
+        final SnapshotsInProgress.Entry snapshotNoShards = snapshotEntry(snapshot, Collections.emptyList(), Map.of());
 
         final String indexName1 = "index-1";
         final ShardId shardId1 = new ShardId(index(indexName1), 0);
@@ -128,7 +128,7 @@ public void testUpdateSnapshotMultipleShards() throws Exception {
         final SnapshotsInProgress.Entry snapshotSingleShard = snapshotEntry(
             sn1,
             Collections.singletonList(indexId1),
-            ImmutableOpenMap.builder(shardsMap(shardId1, shardInitStatus)).fPut(shardId2, shardInitStatus).build()
+            Map.of(shardId1, shardInitStatus, shardId2, shardInitStatus)
         );
 
         assertThat(snapshotSingleShard.state(), is(SnapshotsInProgress.State.STARTED));
@@ -178,7 +178,7 @@ public void testUpdateCloneMultipleShards() throws Exception {
         final SnapshotsInProgress.Entry cloneMultipleShards = cloneEntry(
             targetSnapshot,
             sourceSnapshot.getSnapshotId(),
-            ImmutableOpenMap.builder(clonesMap(shardId1, shardInitStatus)).fPut(shardId2, shardInitStatus).build()
+            Map.of(shardId1, shardInitStatus, shardId2, shardInitStatus)
         );
 
         assertThat(cloneMultipleShards.state(), is(SnapshotsInProgress.State.STARTED));
@@ -371,11 +371,11 @@ public void testCompletedCloneStartsNextClone() throws Exception {
         final String indexName1 = "index-1";
         final IndexId indexId1 = indexId(indexName1);
         final RepositoryShardId shardId1 = new RepositoryShardId(indexId1, 0);
-        final String masterNodeId = uuid();
+        final String clusterManagerNodeId = uuid();
         final SnapshotsInProgress.Entry cloneSingleShard = cloneEntry(
             targetSnapshot,
             sourceSnapshot.getSnapshotId(),
-            clonesMap(shardId1, initShardStatus(masterNodeId))
+            clonesMap(shardId1, initShardStatus(clusterManagerNodeId))
         );
 
         final Snapshot queuedTargetSnapshot = snapshot(repoName, "test-snapshot");
@@ -388,11 +388,11 @@ public void testCompletedCloneStartsNextClone() throws Exception {
         assertThat(cloneSingleShard.state(), is(SnapshotsInProgress.State.STARTED));
 
         final ClusterState stateWithUnassignedRoutingShard = stateWithSnapshots(
-            ClusterState.builder(ClusterState.EMPTY_STATE).nodes(discoveryNodes(masterNodeId)).build(),
+            ClusterState.builder(ClusterState.EMPTY_STATE).nodes(discoveryNodes(clusterManagerNodeId)).build(),
             cloneSingleShard,
             queuedClone
         );
-        final SnapshotsService.ShardSnapshotUpdate completeShardClone = successUpdate(targetSnapshot, shardId1, masterNodeId);
+        final SnapshotsService.ShardSnapshotUpdate completeShardClone = successUpdate(targetSnapshot, shardId1, clusterManagerNodeId);
 
         final ClusterState updatedClusterState = applyUpdates(stateWithUnassignedRoutingShard, completeShardClone);
         final SnapshotsInProgress snapshotsInProgress = updatedClusterState.custom(SnapshotsInProgress.TYPE);
@@ -408,18 +408,18 @@ private static DiscoveryNodes discoveryNodes(String localNodeId) {
         return DiscoveryNodes.builder().localNodeId(localNodeId).build();
     }
 
-    private static ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardsMap(
+    private static Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shardsMap(
         ShardId shardId,
         SnapshotsInProgress.ShardSnapshotStatus shardStatus
     ) {
-        return ImmutableOpenMap.<ShardId, SnapshotsInProgress.ShardSnapshotStatus>builder().fPut(shardId, shardStatus).build();
+        return Map.of(shardId, shardStatus);
     }
 
-    private static ImmutableOpenMap<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clonesMap(
+    private static Map<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clonesMap(
         RepositoryShardId shardId,
         SnapshotsInProgress.ShardSnapshotStatus shardStatus
     ) {
-        return ImmutableOpenMap.<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus>builder().fPut(shardId, shardStatus).build();
+        return Map.of(shardId, shardStatus);
     }
 
     private static SnapshotsService.ShardSnapshotUpdate successUpdate(Snapshot snapshot, ShardId shardId, String nodeId) {
@@ -472,7 +472,7 @@ private static ClusterState applyUpdates(ClusterState state, SnapshotsService.Sh
     private static SnapshotsInProgress.Entry snapshotEntry(
         Snapshot snapshot,
         List<IndexId> indexIds,
-        ImmutableOpenMap<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards
+        final Map<ShardId, SnapshotsInProgress.ShardSnapshotStatus> shards
     ) {
         return SnapshotsInProgress.startedEntry(
             snapshot,
@@ -484,17 +484,18 @@ private static SnapshotsInProgress.Entry snapshotEntry(
             randomNonNegativeLong(),
             shards,
             Collections.emptyMap(),
-            Version.CURRENT
+            Version.CURRENT,
+            false
         );
     }
 
     private static SnapshotsInProgress.Entry cloneEntry(
         Snapshot snapshot,
         SnapshotId source,
-        ImmutableOpenMap<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clones
+        final Map<RepositoryShardId, SnapshotsInProgress.ShardSnapshotStatus> clones
     ) {
-        final List<IndexId> indexIds = StreamSupport.stream(clones.keys().spliterator(), false)
-            .map(k -> k.value.index())
+        final List<IndexId> indexIds = StreamSupport.stream(clones.keySet().spliterator(), false)
+            .map(k -> k.index())
             .distinct()
             .collect(Collectors.toList());
         return SnapshotsInProgress.startClone(snapshot, source, indexIds, 1L, randomNonNegativeLong(), Version.CURRENT).withClones(clones);
diff --git a/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepository.java b/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepository.java
index 6bfd96b328d75..f9388c9e4b86e 100644
--- a/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepository.java
+++ b/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepository.java
@@ -41,9 +41,9 @@
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.blobstore.DeleteResult;
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.snapshots.SnapshotInfo;
@@ -90,7 +90,7 @@ public MockEventuallyConsistentRepository(
         final Context context,
         final Random random
     ) {
-        super(metadata, false, namedXContentRegistry, clusterService, recoverySettings);
+        super(metadata, namedXContentRegistry, clusterService, recoverySettings);
         this.context = context;
         this.namedXContentRegistry = namedXContentRegistry;
         this.random = random;
@@ -373,7 +373,7 @@ public void writeBlob(String blobName, InputStream inputStream, long blobSize, b
                                         new BytesArray(data)
                                     );
                                     // If the existing snapshotInfo differs only in the timestamps it stores, then the overwrite is not
-                                    // a problem and could be the result of a correctly handled master failover.
+                                    // a problem and could be the result of a correctly handled cluster-manager failover.
                                     final SnapshotInfo existingInfo = SNAPSHOT_FORMAT.deserialize(
                                         blobName,
                                         namedXContentRegistry,
diff --git a/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepositoryTests.java b/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepositoryTests.java
index 0dc8d435ec783..43dde7281fb2d 100644
--- a/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepositoryTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/mockstore/MockEventuallyConsistentRepositoryTests.java
@@ -232,7 +232,8 @@ public void testOverwriteSnapshotInfoBlob() throws Exception {
                     5,
                     Collections.emptyList(),
                     true,
-                    Collections.emptyMap()
+                    Collections.emptyMap(),
+                    false
                 ),
                 Version.CURRENT,
                 Function.identity(),
@@ -257,7 +258,8 @@ public void testOverwriteSnapshotInfoBlob() throws Exception {
                             6,
                             Collections.emptyList(),
                             true,
-                            Collections.emptyMap()
+                            Collections.emptyMap(),
+                            false
                         ),
                         Version.CURRENT,
                         Function.identity(),
@@ -284,7 +286,8 @@ public void testOverwriteSnapshotInfoBlob() throws Exception {
                         5,
                         Collections.emptyList(),
                         true,
-                        Collections.emptyMap()
+                        Collections.emptyMap(),
+                        false
                     ),
                     Version.CURRENT,
                     Function.identity(),
diff --git a/server/src/test/java/org/opensearch/tasks/CancelTasksResponseTests.java b/server/src/test/java/org/opensearch/tasks/CancelTasksResponseTests.java
index 64d2979c2c5a0..546ee937e3754 100644
--- a/server/src/test/java/org/opensearch/tasks/CancelTasksResponseTests.java
+++ b/server/src/test/java/org/opensearch/tasks/CancelTasksResponseTests.java
@@ -36,9 +36,9 @@
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.CancelTasksResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
@@ -62,7 +62,7 @@ protected CancelTasksResponse createTestInstance() {
     private static List<TaskInfo> randomTasks() {
         List<TaskInfo> randomTasks = new ArrayList<>();
         for (int i = 0; i < randomInt(10); i++) {
-            randomTasks.add(TaskInfoTests.randomTaskInfo());
+            randomTasks.add(TaskInfoTests.randomTaskInfo(false));
         }
         return randomTasks;
     }
diff --git a/server/src/test/java/org/opensearch/tasks/ListTasksResponseTests.java b/server/src/test/java/org/opensearch/tasks/ListTasksResponseTests.java
index 4d5feb46de1d0..afaf3e4cdaf59 100644
--- a/server/src/test/java/org/opensearch/tasks/ListTasksResponseTests.java
+++ b/server/src/test/java/org/opensearch/tasks/ListTasksResponseTests.java
@@ -36,15 +36,20 @@
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.TaskOperationFailure;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceStats;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.core.tasks.resourcetracker.TaskThreadUsage;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractXContentTestCase;
 
 import java.io.IOException;
 import java.net.ConnectException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
@@ -72,7 +77,13 @@ public void testNonEmptyToString() {
             true,
             false,
             new TaskId("node1", 0),
-            Collections.singletonMap("foo", "bar")
+            Collections.singletonMap("foo", "bar"),
+            new TaskResourceStats(new HashMap<>() {
+                {
+                    put("dummy-type1", new TaskResourceUsage(100, 100));
+                }
+            }, new TaskThreadUsage(10, 10)),
+            0L
         );
         ListTasksResponse tasksResponse = new ListTasksResponse(singletonList(info), emptyList(), emptyList());
         assertEquals(
@@ -93,7 +104,19 @@ public void testNonEmptyToString() {
                 + "      \"parent_task_id\" : \"node1:0\",\n"
                 + "      \"headers\" : {\n"
                 + "        \"foo\" : \"bar\"\n"
-                + "      }\n"
+                + "      },\n"
+                + "      \"resource_stats\" : {\n"
+                + "        \"dummy-type1\" : {\n"
+                + "          \"cpu_time_in_nanos\" : 100,\n"
+                + "          \"memory_in_bytes\" : 100\n"
+                + "        },\n"
+                + "        \"thread_info\" : {\n"
+                + "          \"thread_executions\" : 10,\n"
+                + "          \"active_threads\" : 10\n"
+                + "        }\n"
+                + "      },\n"
+                + "      \"cancellation_time\" : \"0s\",\n"
+                + "      \"cancellation_time_millis\" : 0\n"
                 + "    }\n"
                 + "  ]\n"
                 + "}",
@@ -127,8 +150,8 @@ protected boolean supportsUnknownFields() {
 
     @Override
     protected Predicate<String> getRandomFieldsExcludeFilter() {
-        // status and headers hold arbitrary content, we can't inject random fields in them
-        return field -> field.endsWith("status") || field.endsWith("headers");
+        // status, headers and resource_stats hold arbitrary content, we can't inject random fields in them
+        return field -> field.endsWith("status") || field.endsWith("headers") || field.contains("resource_stats");
     }
 
     @Override
diff --git a/server/src/test/java/org/opensearch/tasks/SearchShardTaskCancellationStatsTests.java b/server/src/test/java/org/opensearch/tasks/SearchShardTaskCancellationStatsTests.java
new file mode 100644
index 0000000000000..ab265b613b897
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/SearchShardTaskCancellationStatsTests.java
@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+public class SearchShardTaskCancellationStatsTests extends AbstractWireSerializingTestCase<SearchShardTaskCancellationStats> {
+    @Override
+    protected Writeable.Reader<SearchShardTaskCancellationStats> instanceReader() {
+        return SearchShardTaskCancellationStats::new;
+    }
+
+    @Override
+    protected SearchShardTaskCancellationStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static SearchShardTaskCancellationStats randomInstance() {
+        return new SearchShardTaskCancellationStats(randomNonNegativeLong(), randomNonNegativeLong());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringServiceTests.java b/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringServiceTests.java
new file mode 100644
index 0000000000000..bb154b95f9f01
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringServiceTests.java
@@ -0,0 +1,373 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.Version;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.transport.MockTransportService;
+import org.opensearch.threadpool.Scheduler;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportRequest;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Phaser;
+import java.util.concurrent.TimeUnit;
+
+import static org.opensearch.tasks.TaskCancellationMonitoringSettings.DURATION_MILLIS_SETTING;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class TaskCancellationMonitoringServiceTests extends OpenSearchTestCase {
+
+    MockTransportService transportService;
+    TaskManager taskManager;
+    ThreadPool threadPool;
+
+    @Before
+    public void setup() {
+        threadPool = new TestThreadPool(getClass().getName());
+        transportService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, NoopTracer.INSTANCE);
+        transportService.start();
+        transportService.acceptIncomingRequests();
+        taskManager = transportService.getTaskManager();
+        taskManager.setTaskCancellationService(new TaskCancellationService(transportService));
+    }
+
+    @After
+    public void cleanup() {
+        transportService.close();
+        ThreadPool.terminate(threadPool, 5, TimeUnit.SECONDS);
+    }
+
+    public void testWithNoCurrentRunningCancelledTasks() {
+        TaskCancellationMonitoringSettings settings = new TaskCancellationMonitoringSettings(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        TaskManager mockTaskManager = mock(TaskManager.class);
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            threadPool,
+            mockTaskManager,
+            settings
+        );
+
+        taskCancellationMonitoringService.doRun();
+        // Task manager should not be invoked.
+        verify(mockTaskManager, times(0)).getTasks();
+    }
+
+    public void testWithNonZeroCancelledSearchShardTasksRunning() throws InterruptedException {
+        Settings settings = Settings.builder()
+            .put(DURATION_MILLIS_SETTING.getKey(), 0) // Setting to zero for testing
+            .build();
+        TaskCancellationMonitoringSettings taskCancellationMonitoringSettings = new TaskCancellationMonitoringSettings(
+            settings,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            threadPool,
+            taskManager,
+            taskCancellationMonitoringSettings
+        );
+        int numTasks = randomIntBetween(5, 50);
+        List<SearchShardTask> tasks = createTasks(numTasks);
+
+        int cancelFromIdx = randomIntBetween(0, numTasks - 1);
+        int cancelTillIdx = randomIntBetween(cancelFromIdx, numTasks - 1);
+
+        int numberOfTasksCancelled = cancelTillIdx - cancelFromIdx + 1;
+        CountDownLatch countDownLatch = cancelTasksConcurrently(tasks, cancelFromIdx, cancelTillIdx);
+
+        countDownLatch.await(); // Wait for all threads execution.
+        taskCancellationMonitoringService.doRun(); // 1st run to verify whether we are able to track running cancelled
+        // tasks.
+        TaskCancellationStats stats = taskCancellationMonitoringService.stats();
+        assertEquals(numberOfTasksCancelled, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numberOfTasksCancelled, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+
+        taskCancellationMonitoringService.doRun(); // 2nd run. Verify same.
+        stats = taskCancellationMonitoringService.stats();
+        assertEquals(numberOfTasksCancelled, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numberOfTasksCancelled, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+        completeTasksConcurrently(tasks, 0, tasks.size() - 1).await();
+        taskCancellationMonitoringService.doRun(); // 3rd run to verify current count is 0 and total remains the same.
+        stats = taskCancellationMonitoringService.stats();
+        assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        assertEquals(0, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numberOfTasksCancelled, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+    }
+
+    public void testShouldRunGetsDisabledAfterTaskCompletion() throws InterruptedException {
+        Settings settings = Settings.builder()
+            .put(DURATION_MILLIS_SETTING.getKey(), 0) // Setting to zero for testing
+            .build();
+        TaskCancellationMonitoringSettings taskCancellationMonitoringSettings = new TaskCancellationMonitoringSettings(
+            settings,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            threadPool,
+            taskManager,
+            taskCancellationMonitoringSettings
+        );
+        assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        assertEquals(0, taskCancellationMonitoringService.getCancelledTaskTracker().size());
+
+        // Start few tasks.
+        int numTasks = randomIntBetween(5, 50);
+        List<SearchShardTask> tasks = createTasks(numTasks);
+
+        taskCancellationMonitoringService.doRun();
+        TaskCancellationStats stats = taskCancellationMonitoringService.stats();
+        // verify no cancelled tasks currently being recorded
+        assertEquals(0, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(0, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+        cancelTasksConcurrently(tasks, 0, tasks.size() - 1).await();
+        taskCancellationMonitoringService.doRun();
+        stats = taskCancellationMonitoringService.stats();
+        assertFalse(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+
+        completeTasksConcurrently(tasks, 0, tasks.size() - 1).await();
+        stats = taskCancellationMonitoringService.stats();
+        assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        assertEquals(0, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+    }
+
+    public void testWithVaryingCancelledTasksDuration() throws InterruptedException {
+        long cancelledTaskDurationThresholdMilis = 2000;
+        Settings settings = Settings.builder()
+            .put(DURATION_MILLIS_SETTING.getKey(), cancelledTaskDurationThresholdMilis) // Setting to one for testing
+            .build();
+        TaskCancellationMonitoringSettings taskCancellationMonitoringSettings = new TaskCancellationMonitoringSettings(
+            settings,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            threadPool,
+            taskManager,
+            taskCancellationMonitoringSettings
+        );
+
+        int numTasks = randomIntBetween(5, 50);
+        List<SearchShardTask> tasks = createTasks(numTasks);
+
+        int numTasksToBeCancelledInFirstIteration = randomIntBetween(1, numTasks - 1);
+        CountDownLatch countDownLatch = cancelTasksConcurrently(tasks, 0, numTasksToBeCancelledInFirstIteration - 1);
+        countDownLatch.await(); // Wait for all tasks to be cancelled in first iteration
+
+        Thread.sleep(cancelledTaskDurationThresholdMilis); // Sleep, so we later verify whether above tasks are being
+        // captured as part of stats.
+
+        taskCancellationMonitoringService.doRun();
+        TaskCancellationStats stats = taskCancellationMonitoringService.stats();
+        // Verify only tasks that were cancelled as part of first iteration is being captured as part of stats as
+        // they have been running longer as per threshold.
+        assertEquals(
+            numTasksToBeCancelledInFirstIteration,
+            stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount()
+        );
+        assertEquals(
+            numTasksToBeCancelledInFirstIteration,
+            stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount()
+        );
+
+        countDownLatch = cancelTasksConcurrently(tasks, numTasksToBeCancelledInFirstIteration, numTasks - 1);
+        countDownLatch.await(); // Wait for rest of tasks to be cancelled.
+
+        Thread.sleep(cancelledTaskDurationThresholdMilis); // Sleep again, so we now verify whether all tasks are
+        // being captured as part of stats.
+        taskCancellationMonitoringService.doRun();
+        stats = taskCancellationMonitoringService.stats();
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+
+        completeTasksConcurrently(tasks, 0, tasks.size() - 1).await();
+        taskCancellationMonitoringService.doRun();
+        stats = taskCancellationMonitoringService.stats();
+        // Verify no current running tasks
+        assertEquals(0, stats.getSearchShardTaskCancellationStats().getCurrentLongRunningCancelledTaskCount());
+        assertEquals(numTasks, stats.getSearchShardTaskCancellationStats().getTotalLongRunningCancelledTaskCount());
+    }
+
+    public void testTasksAreGettingEvictedCorrectlyAfterCompletion() throws InterruptedException {
+        Settings settings = Settings.builder()
+            .put(DURATION_MILLIS_SETTING.getKey(), 0) // Setting to one for testing
+            .build();
+        TaskCancellationMonitoringSettings taskCancellationMonitoringSettings = new TaskCancellationMonitoringSettings(
+            settings,
+            new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            threadPool,
+            taskManager,
+            taskCancellationMonitoringSettings
+        );
+
+        // Start few tasks.
+        int numTasks = randomIntBetween(5, 50);
+        List<SearchShardTask> tasks = createTasks(numTasks);
+        assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        int numTasksToBeCancelledInFirstIteration = randomIntBetween(2, numTasks - 1);
+        CountDownLatch countDownLatch = cancelTasksConcurrently(tasks, 0, numTasksToBeCancelledInFirstIteration - 1);
+        countDownLatch.await(); // Wait for all tasks to be cancelled in first iteration
+
+        assertEquals(numTasksToBeCancelledInFirstIteration, taskCancellationMonitoringService.getCancelledTaskTracker().size());
+        // Verify desired task ids are present.
+        for (int itr = 0; itr < numTasksToBeCancelledInFirstIteration; itr++) {
+            assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(itr).getId()));
+        }
+        // Cancel rest of the tasks
+        cancelTasksConcurrently(tasks, numTasksToBeCancelledInFirstIteration, numTasks - 1).await();
+        for (int itr = 0; itr < tasks.size(); itr++) {
+            assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(itr).getId()));
+        }
+        // Complete one task to start with.
+        completeTasksConcurrently(tasks, 0, 0).await();
+        assertFalse(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(0).getId()));
+        // Verify rest of the tasks are still present in tracker
+        for (int itr = 1; itr < tasks.size(); itr++) {
+            assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(itr).getId()));
+        }
+        // Complete first iteration tasks
+        completeTasksConcurrently(tasks, 1, numTasksToBeCancelledInFirstIteration - 1).await();
+        // Verify desired tasks were evicted from tracker map
+        for (int itr = 0; itr < numTasksToBeCancelledInFirstIteration; itr++) {
+            assertFalse(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(0).getId()));
+        }
+        // Verify rest of the tasks are still present in tracker
+        for (int itr = numTasksToBeCancelledInFirstIteration; itr < tasks.size(); itr++) {
+            assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(itr).getId()));
+        }
+        // Complete all of them finally
+        completeTasksConcurrently(tasks, numTasksToBeCancelledInFirstIteration, tasks.size() - 1).await();
+        assertTrue(taskCancellationMonitoringService.getCancelledTaskTracker().isEmpty());
+        for (int itr = 0; itr < tasks.size(); itr++) {
+            assertFalse(taskCancellationMonitoringService.getCancelledTaskTracker().containsKey(tasks.get(itr).getId()));
+        }
+    }
+
+    public void testDoStartAndStop() {
+        TaskCancellationMonitoringSettings settings = new TaskCancellationMonitoringSettings(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        ThreadPool mockThreadPool = mock(ThreadPool.class);
+        Scheduler.Cancellable scheduleFuture = mock(Scheduler.Cancellable.class);
+        when(scheduleFuture.cancel()).thenReturn(true);
+        when(mockThreadPool.scheduleWithFixedDelay(any(), any(), any())).thenReturn(scheduleFuture);
+        TaskCancellationMonitoringService taskCancellationMonitoringService = new TaskCancellationMonitoringService(
+            mockThreadPool,
+            taskManager,
+            settings
+        );
+
+        taskCancellationMonitoringService.doStart();
+        taskCancellationMonitoringService.doStop();
+        verify(scheduleFuture, times(1)).cancel();
+    }
+
+    private List<SearchShardTask> createTasks(int numTasks) {
+        List<SearchShardTask> tasks = new ArrayList<>(numTasks);
+        for (int i = 0; i < numTasks; i++) {
+            tasks.add((SearchShardTask) taskManager.register("type-" + i, "action-" + i, new MockQuerySearchRequest()));
+        }
+        return tasks;
+    }
+
+    // Caller can this with the list of tasks specifically mentioning which ones to cancel. And can call CountDownLatch
+    // .await() to wait for all tasks be cancelled.
+    private CountDownLatch cancelTasksConcurrently(List<? extends CancellableTask> tasks, int cancelFromIdx, int cancelTillIdx) {
+        assert cancelFromIdx >= 0;
+        assert cancelTillIdx <= tasks.size() - 1;
+        assert cancelTillIdx >= cancelFromIdx;
+        int totalTasksToBeCancelled = cancelTillIdx - cancelFromIdx + 1;
+        Thread[] threads = new Thread[totalTasksToBeCancelled];
+        Phaser phaser = new Phaser(totalTasksToBeCancelled + 1); // Used to concurrently cancel tasks by multiple threads.
+        CountDownLatch countDownLatch = new CountDownLatch(totalTasksToBeCancelled); // To wait for all threads to finish.
+        for (int i = 0; i < totalTasksToBeCancelled; i++) {
+            int idx = i + cancelFromIdx;
+            threads[i] = new Thread(() -> {
+                phaser.arriveAndAwaitAdvance();
+                taskManager.cancel(tasks.get(idx), "test", () -> {});
+                countDownLatch.countDown();
+            });
+            threads[i].start();
+        }
+        phaser.arriveAndAwaitAdvance();
+        return countDownLatch;
+    }
+
+    private CountDownLatch completeTasksConcurrently(List<? extends CancellableTask> tasks, int completeFromIdx, int completeTillIdx) {
+        assert completeFromIdx >= 0;
+        assert completeTillIdx <= tasks.size() - 1;
+        assert completeTillIdx >= completeFromIdx;
+        int totalTasksToBeCompleted = completeTillIdx - completeFromIdx + 1;
+        Thread[] threads = new Thread[totalTasksToBeCompleted];
+        Phaser phaser = new Phaser(totalTasksToBeCompleted + 1);
+        CountDownLatch countDownLatch = new CountDownLatch(totalTasksToBeCompleted);
+        for (int i = 0; i < totalTasksToBeCompleted; i++) {
+            int idx = i + completeFromIdx;
+            threads[i] = new Thread(() -> {
+                phaser.arriveAndAwaitAdvance();
+                taskManager.unregister(tasks.get(idx));
+                countDownLatch.countDown();
+            });
+            threads[i].start();
+        }
+        phaser.arriveAndAwaitAdvance();
+        return countDownLatch;
+    }
+
+    public static class MockQuerySearchRequest extends TransportRequest {
+        protected String requestName;
+
+        public MockQuerySearchRequest() {
+            super();
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+            out.writeString(requestName);
+        }
+
+        @Override
+        public String getDescription() {
+            return "MockQuerySearchRequest[" + requestName + "]";
+        }
+
+        @Override
+        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
+            return new SearchShardTask(id, type, action, getDescription(), parentTaskId, headers);
+        }
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringSettingsTests.java b/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringSettingsTests.java
new file mode 100644
index 0000000000000..245f410b2609a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/TaskCancellationMonitoringSettingsTests.java
@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchTestCase;
+
+public class TaskCancellationMonitoringSettingsTests extends OpenSearchTestCase {
+
+    public void testDefaults() {
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        TaskCancellationMonitoringSettings settings = new TaskCancellationMonitoringSettings(Settings.EMPTY, clusterSettings);
+        assertEquals(TaskCancellationMonitoringSettings.DURATION_MILLIS_SETTING_DEFAULT_VALUE, settings.getDuration().millis());
+        assertEquals(TaskCancellationMonitoringSettings.INTERVAL_MILLIS_SETTING_DEFAULT_VALUE, settings.getInterval().millis());
+        assertEquals(TaskCancellationMonitoringSettings.IS_ENABLED_SETTING_DEFAULT_VALUE, settings.isEnabled());
+    }
+
+    public void testUpdate() {
+        ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
+        TaskCancellationMonitoringSettings settings = new TaskCancellationMonitoringSettings(Settings.EMPTY, clusterSettings);
+
+        Settings newSettings = Settings.builder()
+            .put(TaskCancellationMonitoringSettings.DURATION_MILLIS_SETTING.getKey(), 20000)
+            .put(TaskCancellationMonitoringSettings.INTERVAL_MILLIS_SETTING.getKey(), 2000)
+            .put(TaskCancellationMonitoringSettings.IS_ENABLED_SETTING.getKey(), false)
+            .build();
+        clusterSettings.applySettings(newSettings);
+        assertEquals(20000, settings.getDuration().millis());
+        assertFalse(settings.isEnabled());
+        assertNotEquals(2000, settings.getInterval().millis());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskCancellationStatsTests.java b/server/src/test/java/org/opensearch/tasks/TaskCancellationStatsTests.java
new file mode 100644
index 0000000000000..beef05b04ab7a
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/TaskCancellationStatsTests.java
@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.test.AbstractWireSerializingTestCase;
+
+public class TaskCancellationStatsTests extends AbstractWireSerializingTestCase<TaskCancellationStats> {
+    @Override
+    protected Writeable.Reader<TaskCancellationStats> instanceReader() {
+        return TaskCancellationStats::new;
+    }
+
+    @Override
+    protected TaskCancellationStats createTestInstance() {
+        return randomInstance();
+    }
+
+    public static TaskCancellationStats randomInstance() {
+        return new TaskCancellationStats(SearchShardTaskCancellationStatsTests.randomInstance());
+    }
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskCancellationTests.java b/server/src/test/java/org/opensearch/tasks/TaskCancellationTests.java
new file mode 100644
index 0000000000000..e74f89c905499
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/TaskCancellationTests.java
@@ -0,0 +1,77 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.search.backpressure.trackers.TaskResourceUsageTracker;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+public class TaskCancellationTests extends OpenSearchTestCase {
+
+    public void testTaskCancellation() {
+        SearchShardTask mockTask = new SearchShardTask(123L, "", "", "", null, Collections.emptyMap());
+
+        TaskResourceUsageTracker mockTracker1 = createMockTaskResourceUsageTracker("mock_tracker_1");
+        TaskResourceUsageTracker mockTracker2 = createMockTaskResourceUsageTracker("mock_tracker_2");
+        TaskResourceUsageTracker mockTracker3 = createMockTaskResourceUsageTracker("mock_tracker_3");
+
+        List<TaskCancellation.Reason> reasons = new ArrayList<>();
+        List<Runnable> callbacks = List.of(mockTracker1::incrementCancellations, mockTracker2::incrementCancellations);
+        TaskCancellation taskCancellation = new TaskCancellation(mockTask, reasons, callbacks);
+
+        // Task does not have any reason to be cancelled.
+        assertEquals(0, taskCancellation.totalCancellationScore());
+        assertFalse(taskCancellation.isEligibleForCancellation());
+        taskCancellation.cancel();
+        assertEquals(0, mockTracker1.getCancellations());
+        assertEquals(0, mockTracker2.getCancellations());
+        assertEquals(0, mockTracker3.getCancellations());
+
+        // Task has one or more reasons to be cancelled.
+        reasons.add(new TaskCancellation.Reason("limits exceeded 1", 10));
+        reasons.add(new TaskCancellation.Reason("limits exceeded 2", 20));
+        reasons.add(new TaskCancellation.Reason("limits exceeded 3", 5));
+        assertEquals(35, taskCancellation.totalCancellationScore());
+        assertTrue(taskCancellation.isEligibleForCancellation());
+
+        // Cancel the task and validate the cancellation reason and invocation of callbacks.
+        taskCancellation.cancel();
+        assertTrue(mockTask.getReasonCancelled().contains("limits exceeded 1, limits exceeded 2, limits exceeded 3"));
+        assertEquals(1, mockTracker1.getCancellations());
+        assertEquals(1, mockTracker2.getCancellations());
+        assertEquals(0, mockTracker3.getCancellations());
+    }
+
+    private static TaskResourceUsageTracker createMockTaskResourceUsageTracker(String name) {
+        return new TaskResourceUsageTracker() {
+            @Override
+            public String name() {
+                return name;
+            }
+
+            @Override
+            public void update(Task task) {}
+
+            @Override
+            public Optional<TaskCancellation.Reason> checkAndMaybeGetCancellationReason(Task task) {
+                return Optional.empty();
+            }
+
+            @Override
+            public Stats stats(List<? extends Task> activeTasks) {
+                return null;
+            }
+        };
+    }
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskIdTests.java b/server/src/test/java/org/opensearch/tasks/TaskIdTests.java
index 2789daa7f0481..d4a97cac6bd58 100644
--- a/server/src/test/java/org/opensearch/tasks/TaskIdTests.java
+++ b/server/src/test/java/org/opensearch/tasks/TaskIdTests.java
@@ -33,9 +33,10 @@
 package org.opensearch.tasks;
 
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/tasks/TaskInfoTests.java b/server/src/test/java/org/opensearch/tasks/TaskInfoTests.java
index 89b690d81a4ea..75cf57a24a95a 100644
--- a/server/src/test/java/org/opensearch/tasks/TaskInfoTests.java
+++ b/server/src/test/java/org/opensearch/tasks/TaskInfoTests.java
@@ -33,11 +33,15 @@
 package org.opensearch.tasks;
 
 import org.opensearch.client.Requests;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceStats;
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.core.tasks.resourcetracker.TaskThreadUsage;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.AbstractSerializingTestCase;
 
 import java.io.IOException;
@@ -77,13 +81,13 @@ protected boolean supportsUnknownFields() {
 
     @Override
     protected Predicate<String> getRandomFieldsExcludeFilter() {
-        // status and headers hold arbitrary content, we can't inject random fields in them
-        return field -> "status".equals(field) || "headers".equals(field);
+        // status, headers and resource_stats hold arbitrary content, we can't inject random fields in them
+        return field -> "status".equals(field) || "headers".equals(field) || field.contains("resource_stats");
     }
 
     @Override
     protected TaskInfo mutateInstance(TaskInfo info) {
-        switch (between(0, 9)) {
+        switch (between(0, 11)) {
             case 0:
                 TaskId taskId = new TaskId(info.getTaskId().getNodeId() + randomAlphaOfLength(5), info.getTaskId().getId());
                 return new TaskInfo(
@@ -97,7 +101,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 1:
                 return new TaskInfo(
@@ -111,7 +117,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 2:
                 return new TaskInfo(
@@ -125,7 +133,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 3:
                 return new TaskInfo(
@@ -139,7 +149,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 4:
                 Task.Status newStatus = randomValueOtherThan(info.getStatus(), TaskInfoTests::randomRawTaskStatus);
@@ -154,7 +166,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 5:
                 return new TaskInfo(
@@ -168,7 +182,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 6:
                 return new TaskInfo(
@@ -182,7 +198,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 7:
                 return new TaskInfo(
@@ -196,7 +214,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable() == false,
                     false,
                     info.getParentTaskId(),
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 8:
                 TaskId parentId = new TaskId(info.getParentTaskId().getNodeId() + randomAlphaOfLength(5), info.getParentTaskId().getId());
@@ -211,7 +231,9 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     parentId,
-                    info.getHeaders()
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
                 );
             case 9:
                 Map<String, String> headers = info.getHeaders();
@@ -232,7 +254,47 @@ protected TaskInfo mutateInstance(TaskInfo info) {
                     info.isCancellable(),
                     info.isCancelled(),
                     info.getParentTaskId(),
-                    headers
+                    headers,
+                    info.getResourceStats(),
+                    info.getCancellationStartTime()
+                );
+            case 10:
+                Map<String, TaskResourceUsage> resourceUsageMap;
+                if (info.getResourceStats() == null) {
+                    resourceUsageMap = new HashMap<>(1);
+                } else {
+                    resourceUsageMap = new HashMap<>(info.getResourceStats().getResourceUsageInfo());
+                }
+                resourceUsageMap.put(randomAlphaOfLength(5), new TaskResourceUsage(randomNonNegativeLong(), randomNonNegativeLong()));
+                return new TaskInfo(
+                    info.getTaskId(),
+                    info.getType(),
+                    info.getAction(),
+                    info.getDescription(),
+                    info.getStatus(),
+                    info.getStartTime(),
+                    info.getRunningTimeNanos(),
+                    info.isCancellable(),
+                    info.isCancelled(),
+                    info.getParentTaskId(),
+                    info.getHeaders(),
+                    new TaskResourceStats(resourceUsageMap, new TaskThreadUsage(randomInt(10), randomInt(10)))
+                );
+            case 11:
+                return new TaskInfo(
+                    info.getTaskId(),
+                    info.getType(),
+                    info.getAction(),
+                    info.getDescription(),
+                    info.getStatus(),
+                    info.getStartTime(),
+                    info.getRunningTimeNanos(),
+                    true,
+                    true,
+                    info.getParentTaskId(),
+                    info.getHeaders(),
+                    info.getResourceStats(),
+                    randomNonNegativeLong()
                 );
             default:
                 throw new IllegalStateException();
@@ -240,15 +302,23 @@ protected TaskInfo mutateInstance(TaskInfo info) {
     }
 
     static TaskInfo randomTaskInfo() {
+        return randomTaskInfo(randomBoolean());
+    }
+
+    static TaskInfo randomTaskInfo(boolean detailed) {
         TaskId taskId = randomTaskId();
         String type = randomAlphaOfLength(5);
         String action = randomAlphaOfLength(5);
-        Task.Status status = randomBoolean() ? randomRawTaskStatus() : null;
-        String description = randomBoolean() ? randomAlphaOfLength(5) : null;
+        Task.Status status = detailed ? randomRawTaskStatus() : null;
+        String description = detailed ? randomAlphaOfLength(5) : null;
         long startTime = randomLong();
         long runningTimeNanos = randomLong();
         boolean cancellable = randomBoolean();
         boolean cancelled = cancellable == true ? randomBoolean() : false;
+        Long cancellationStartTime = null;
+        if (cancelled) {
+            cancellationStartTime = randomNonNegativeLong();
+        }
         TaskId parentTaskId = randomBoolean() ? TaskId.EMPTY_TASK_ID : randomTaskId();
         Map<String, String> headers = randomBoolean()
             ? Collections.emptyMap()
@@ -264,7 +334,9 @@ static TaskInfo randomTaskInfo() {
             cancellable,
             cancelled,
             parentTaskId,
-            headers
+            headers,
+            randomResourceStats(detailed),
+            cancellationStartTime
         );
     }
 
@@ -275,7 +347,7 @@ private static TaskId randomTaskId() {
     private static RawTaskStatus randomRawTaskStatus() {
         try (XContentBuilder builder = XContentBuilder.builder(Requests.INDEX_CONTENT_TYPE.xContent())) {
             builder.startObject();
-            int fields = between(0, 10);
+            int fields = between(0, 11);
             for (int f = 0; f < fields; f++) {
                 builder.field(randomAlphaOfLength(5), randomAlphaOfLength(5));
             }
@@ -285,4 +357,14 @@ private static RawTaskStatus randomRawTaskStatus() {
             throw new IllegalStateException(e);
         }
     }
+
+    public static TaskResourceStats randomResourceStats(boolean detailed) {
+        return detailed ? new TaskResourceStats(new HashMap<>() {
+            {
+                for (int i = 0; i < randomInt(5); i++) {
+                    put(randomAlphaOfLength(5), new TaskResourceUsage(randomNonNegativeLong(), randomNonNegativeLong()));
+                }
+            }
+        }, new TaskThreadUsage(randomInt(10), randomInt(10))) : null;
+    }
 }
diff --git a/server/src/test/java/org/opensearch/tasks/TaskManagerTests.java b/server/src/test/java/org/opensearch/tasks/TaskManagerTests.java
index 0f09b0de34206..fac5c89cdfc92 100644
--- a/server/src/test/java/org/opensearch/tasks/TaskManagerTests.java
+++ b/server/src/test/java/org/opensearch/tasks/TaskManagerTests.java
@@ -32,14 +32,16 @@
 
 package org.opensearch.tasks;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.node.tasks.TransportTasksActionTests;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.RunnableTaskExecutionListener;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.FakeTcpChannel;
@@ -59,6 +61,7 @@
 import java.util.Set;
 import java.util.concurrent.Phaser;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.everyItem;
@@ -67,10 +70,12 @@
 
 public class TaskManagerTests extends OpenSearchTestCase {
     private ThreadPool threadPool;
+    private AtomicReference<RunnableTaskExecutionListener> runnableTaskListener;
 
     @Before
     public void setupThreadPool() {
-        threadPool = new TestThreadPool(TransportTasksActionTests.class.getSimpleName());
+        runnableTaskListener = new AtomicReference<>();
+        threadPool = new TestThreadPool(TransportTasksActionTests.class.getSimpleName(), runnableTaskListener);
     }
 
     @After
diff --git a/server/src/test/java/org/opensearch/tasks/TaskResourceTrackingServiceTests.java b/server/src/test/java/org/opensearch/tasks/TaskResourceTrackingServiceTests.java
new file mode 100644
index 0000000000000..45d438f8d04c9
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/TaskResourceTrackingServiceTests.java
@@ -0,0 +1,151 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks;
+
+import org.opensearch.action.admin.cluster.node.tasks.TransportTasksActionTests;
+import org.opensearch.action.search.SearchTask;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.tasks.resourcetracker.ThreadResourceInfo;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.TestThreadPool;
+import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.opensearch.core.tasks.resourcetracker.ResourceStats.CPU;
+import static org.opensearch.core.tasks.resourcetracker.ResourceStats.MEMORY;
+import static org.opensearch.tasks.TaskResourceTrackingService.TASK_ID;
+
+public class TaskResourceTrackingServiceTests extends OpenSearchTestCase {
+
+    private ThreadPool threadPool;
+    private TaskResourceTrackingService taskResourceTrackingService;
+
+    @Before
+    public void setup() {
+        threadPool = new TestThreadPool(TransportTasksActionTests.class.getSimpleName(), new AtomicReference<>());
+        taskResourceTrackingService = new TaskResourceTrackingService(
+            Settings.EMPTY,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+    }
+
+    @After
+    public void terminateThreadPool() {
+        terminate(threadPool);
+    }
+
+    public void testThreadContextUpdateOnTrackingStart() {
+        taskResourceTrackingService.setTaskResourceTrackingEnabled(true);
+
+        Task task = new SearchTask(1, "test", "test", () -> "Test", TaskId.EMPTY_TASK_ID, new HashMap<>());
+
+        String key = "KEY";
+        String value = "VALUE";
+
+        // Prepare thread context
+        threadPool.getThreadContext().putHeader(key, value);
+        threadPool.getThreadContext().putTransient(key, value);
+        threadPool.getThreadContext().addResponseHeader(key, value);
+
+        ThreadContext.StoredContext storedContext = taskResourceTrackingService.startTracking(task);
+
+        // All headers should be preserved and Task Id should also be included in thread context
+        verifyThreadContextFixedHeaders(key, value);
+        assertEquals((long) threadPool.getThreadContext().getTransient(TASK_ID), task.getId());
+
+        storedContext.restore();
+
+        // Post restore only task id should be removed from the thread context
+        verifyThreadContextFixedHeaders(key, value);
+        assertNull(threadPool.getThreadContext().getTransient(TASK_ID));
+    }
+
+    public void testStopTrackingHandlesCurrentActiveThread() {
+        taskResourceTrackingService.setTaskResourceTrackingEnabled(true);
+        Task task = new SearchTask(1, "test", "test", () -> "Test", TaskId.EMPTY_TASK_ID, new HashMap<>());
+        ThreadContext.StoredContext storedContext = taskResourceTrackingService.startTracking(task);
+        long threadId = Thread.currentThread().getId();
+        taskResourceTrackingService.taskExecutionStartedOnThread(task.getId(), threadId);
+
+        assertTrue(task.getResourceStats().get(threadId).get(0).isActive());
+        assertEquals(0, task.getResourceStats().get(threadId).get(0).getResourceUsageInfo().getStatsInfo().get(MEMORY).getTotalValue());
+
+        taskResourceTrackingService.stopTracking(task);
+
+        // Makes sure stop tracking marks the current active thread inactive and refreshes the resource stats before returning.
+        assertFalse(task.getResourceStats().get(threadId).get(0).isActive());
+        assertTrue(task.getResourceStats().get(threadId).get(0).getResourceUsageInfo().getStatsInfo().get(MEMORY).getTotalValue() > 0);
+    }
+
+    /**
+     * Test if taskResourceTrackingService properly tracks resource usage when multiple threads work on the same task
+     */
+    public void testStartingTrackingHandlesMultipleThreadsPerTask() throws InterruptedException {
+        ExecutorService executor = threadPool.executor(ThreadPool.Names.GENERIC);
+        taskResourceTrackingService.setTaskResourceTrackingEnabled(true);
+        Task task = new SearchTask(1, "test", "test", () -> "Test", TaskId.EMPTY_TASK_ID, new HashMap<>());
+        taskResourceTrackingService.startTracking(task);
+        int numTasks = randomIntBetween(2, 100);
+        for (int i = 0; i < numTasks; i++) {
+            executor.execute(() -> {
+                long threadId = Thread.currentThread().getId();
+                taskResourceTrackingService.taskExecutionStartedOnThread(task.getId(), threadId);
+                // The same thread may pick up multiple runnables for the same task id
+                assertEquals(1, task.getResourceStats().get(threadId).stream().filter(ThreadResourceInfo::isActive).count());
+                taskResourceTrackingService.taskExecutionFinishedOnThread(task.getId(), threadId);
+            });
+        }
+        executor.shutdown();
+        while (true) {
+            try {
+                if (executor.awaitTermination(1, TimeUnit.MINUTES)) break;
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        Map<Long, List<ThreadResourceInfo>> stats = task.getResourceStats();
+        int numExecutions = 0;
+        for (Long threadId : stats.keySet()) {
+            for (ThreadResourceInfo info : task.getResourceStats().get(threadId)) {
+                assertTrue(info.getResourceUsageInfo().getStatsInfo().get(MEMORY).getTotalValue() > 0);
+                assertTrue(info.getResourceUsageInfo().getStatsInfo().get(CPU).getTotalValue() > 0);
+                assertFalse(info.isActive());
+                numExecutions++;
+            }
+
+        }
+        assertTrue(task.getTotalResourceStats().getCpuTimeInNanos() > 0);
+        assertTrue(task.getTotalResourceStats().getMemoryInBytes() > 0);
+        // Basic sanity testing that min < average < max < total
+        assertTrue(task.getMinResourceStats().getMemoryInBytes() < task.getAverageResourceStats().getMemoryInBytes());
+        assertTrue(task.getAverageResourceStats().getMemoryInBytes() < task.getMaxResourceStats().getMemoryInBytes());
+        assertTrue(task.getMaxResourceStats().getMemoryInBytes() < task.getTotalResourceStats().getMemoryInBytes());
+        // Each execution of a runnable should record an entry in resourceStats even if it's the same thread
+        assertEquals(numTasks, numExecutions);
+    }
+
+    private void verifyThreadContextFixedHeaders(String key, String value) {
+        assertEquals(threadPool.getThreadContext().getHeader(key), value);
+        assertEquals(threadPool.getThreadContext().getTransient(key), value);
+        assertEquals(threadPool.getThreadContext().getResponseHeaders().get(key).get(0), value);
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/tasks/TaskResultTests.java b/server/src/test/java/org/opensearch/tasks/TaskResultTests.java
index 4f5fd441f6269..447a98b2a43f9 100644
--- a/server/src/test/java/org/opensearch/tasks/TaskResultTests.java
+++ b/server/src/test/java/org/opensearch/tasks/TaskResultTests.java
@@ -33,14 +33,14 @@
 package org.opensearch.tasks;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -120,7 +120,7 @@ private XContentBuilder addRandomUnknownFields(XContentBuilder builder) throws I
                     map.put("unknown_field" + i, Collections.singletonMap("inner", randomAlphaOfLength(20)));
                 }
             }
-            XContentBuilder xContentBuilder = XContentFactory.contentBuilder(parser.contentType());
+            XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(parser.contentType());
             return xContentBuilder.map(map);
         }
     }
diff --git a/server/src/test/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessageTests.java b/server/src/test/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessageTests.java
new file mode 100644
index 0000000000000..099f70a3b14d3
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/consumer/SearchShardTaskDetailsLogMessageTests.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks.consumer;
+
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.core.tasks.resourcetracker.ResourceStatsType;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageMetric;
+import org.opensearch.tasks.Task;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+
+import java.util.Collections;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class SearchShardTaskDetailsLogMessageTests extends OpenSearchSingleNodeTestCase {
+    public void testTaskDetailsLogHasJsonFields() {
+        SearchShardTask task = new SearchShardTask(
+            0,
+            "n/a",
+            "n/a",
+            "test",
+            null,
+            Collections.singletonMap(Task.X_OPAQUE_ID, "my_id"),
+            () -> "test_metadata"
+        );
+        SearchShardTaskDetailsLogMessage p = new SearchShardTaskDetailsLogMessage(task);
+
+        assertThat(p.getValueFor("taskId"), equalTo("0"));
+        assertThat(p.getValueFor("type"), equalTo("n/a"));
+        assertThat(p.getValueFor("action"), equalTo("n/a"));
+        assertThat(p.getValueFor("description"), equalTo("test"));
+        assertThat(p.getValueFor("parentTaskId"), equalTo(null));
+        // when no resource information present
+        assertThat(p.getValueFor("resource_stats"), equalTo("{}"));
+        assertThat(p.getValueFor("metadata"), equalTo("test_metadata"));
+
+        task.startThreadResourceTracking(
+            0,
+            ResourceStatsType.WORKER_STATS,
+            new ResourceUsageMetric(ResourceStats.MEMORY, 0L),
+            new ResourceUsageMetric(ResourceStats.CPU, 0L)
+        );
+        task.updateThreadResourceStats(
+            0,
+            ResourceStatsType.WORKER_STATS,
+            new ResourceUsageMetric(ResourceStats.MEMORY, 100),
+            new ResourceUsageMetric(ResourceStats.CPU, 100)
+        );
+        assertThat(
+            p.getValueFor("resource_stats"),
+            equalTo("{0=[{cpu_time_in_nanos=100, memory_in_bytes=100}, stats_type=worker_stats, is_active=true, threadId=0]}")
+        );
+    }
+}
diff --git a/server/src/test/java/org/opensearch/tasks/consumer/TopNSearchTasksLoggerTests.java b/server/src/test/java/org/opensearch/tasks/consumer/TopNSearchTasksLoggerTests.java
new file mode 100644
index 0000000000000..68dd3327cb52c
--- /dev/null
+++ b/server/src/test/java/org/opensearch/tasks/consumer/TopNSearchTasksLoggerTests.java
@@ -0,0 +1,140 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.tasks.consumer;
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.core.LogEvent;
+import org.opensearch.action.search.SearchShardTask;
+import org.opensearch.common.logging.Loggers;
+import org.opensearch.common.logging.MockAppender;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.tasks.resourcetracker.ResourceStats;
+import org.opensearch.core.tasks.resourcetracker.ResourceStatsType;
+import org.opensearch.core.tasks.resourcetracker.ResourceUsageMetric;
+import org.opensearch.tasks.Task;
+import org.opensearch.test.OpenSearchSingleNodeTestCase;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+
+import java.util.Collections;
+
+import static org.opensearch.tasks.consumer.TopNSearchTasksLogger.LOG_TOP_QUERIES_FREQUENCY_SETTING;
+import static org.opensearch.tasks.consumer.TopNSearchTasksLogger.LOG_TOP_QUERIES_SIZE_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+public class TopNSearchTasksLoggerTests extends OpenSearchSingleNodeTestCase {
+    static MockAppender appender;
+    static Logger searchLogger = LogManager.getLogger(TopNSearchTasksLogger.TASK_DETAILS_LOG_PREFIX + ".search");
+
+    private TopNSearchTasksLogger topNSearchTasksLogger;
+
+    @BeforeClass
+    public static void init() throws IllegalAccessException {
+        appender = new MockAppender("trace_appender");
+        appender.start();
+        Loggers.addAppender(searchLogger, appender);
+    }
+
+    @After
+    public void cleanupAfterTest() {
+        assertAcked(
+            client().admin()
+                .cluster()
+                .prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().putNull("*"))
+                .setTransientSettings(Settings.builder().putNull("*"))
+        );
+    }
+
+    @AfterClass
+    public static void cleanup() {
+        Loggers.removeAppender(searchLogger, appender);
+        appender.stop();
+    }
+
+    public void testLoggerWithTasks() {
+        final Settings settings = Settings.builder()
+            .put(LOG_TOP_QUERIES_SIZE_SETTING.getKey(), 1)
+            .put(LOG_TOP_QUERIES_FREQUENCY_SETTING.getKey(), "60s")
+            .build();
+        topNSearchTasksLogger = new TopNSearchTasksLogger(
+            settings,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        // This setting overrides is just for testing purpose
+        topNSearchTasksLogger.setTopQueriesLogFrequencyInNanos(TimeValue.timeValueMillis(0));
+        generateTasks(5);
+        LogEvent logEvent = appender.getLastEventAndReset();
+        assertNotNull(logEvent);
+        assertEquals(logEvent.getLevel(), Level.INFO);
+        assertTrue(logEvent.getMessage().getFormattedMessage().contains("cpu_time_in_nanos=300, memory_in_bytes=300"));
+    }
+
+    public void testLoggerWithoutTasks() {
+        final Settings settings = Settings.builder()
+            .put(LOG_TOP_QUERIES_SIZE_SETTING.getKey(), 1)
+            .put(LOG_TOP_QUERIES_FREQUENCY_SETTING.getKey(), "60s")
+            .build();
+        topNSearchTasksLogger = new TopNSearchTasksLogger(
+            settings,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+
+        assertNull(appender.getLastEventAndReset());
+    }
+
+    public void testLoggerWithHighFrequency() {
+        // setting the frequency to a really large value and confirming that nothing gets written to log file.
+        final Settings settings = Settings.builder()
+            .put(LOG_TOP_QUERIES_SIZE_SETTING.getKey(), 1)
+            .put(LOG_TOP_QUERIES_FREQUENCY_SETTING.getKey(), "10m")
+            .build();
+        topNSearchTasksLogger = new TopNSearchTasksLogger(
+            settings,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+        );
+        generateTasks(5);
+        generateTasks(2);
+
+        assertNull(appender.getLastEventAndReset());
+    }
+
+    // generate search tasks and updates the topN search tasks logger consumer.
+    public void generateTasks(int numberOfTasks) {
+        for (int i = 0; i < numberOfTasks; i++) {
+            Task task = new SearchShardTask(
+                i,
+                "n/a",
+                "n/a",
+                "test",
+                null,
+                Collections.singletonMap(Task.X_OPAQUE_ID, "my_id"),
+                () -> "n/a"
+            );
+            task.startThreadResourceTracking(
+                i,
+                ResourceStatsType.WORKER_STATS,
+                new ResourceUsageMetric(ResourceStats.MEMORY, 0L),
+                new ResourceUsageMetric(ResourceStats.CPU, 0L)
+            );
+            task.updateThreadResourceStats(
+                i,
+                ResourceStatsType.WORKER_STATS,
+                new ResourceUsageMetric(ResourceStats.MEMORY, i * 100L),
+                new ResourceUsageMetric(ResourceStats.CPU, i * 100L)
+            );
+            topNSearchTasksLogger.accept(task);
+        }
+    }
+}
diff --git a/server/src/test/java/org/opensearch/telemetry/TelemetryModuleTests.java b/server/src/test/java/org/opensearch/telemetry/TelemetryModuleTests.java
new file mode 100644
index 0000000000000..45344ab4253f7
--- /dev/null
+++ b/server/src/test/java/org/opensearch/telemetry/TelemetryModuleTests.java
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry;
+
+import org.opensearch.plugins.TelemetryPlugin;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+import java.util.Optional;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TelemetryModuleTests extends OpenSearchTestCase {
+
+    public void testGetTelemetrySuccess() {
+        TelemetryPlugin telemetryPlugin = mock(TelemetryPlugin.class);
+        when(telemetryPlugin.getName()).thenReturn("otel");
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(telemetryPlugin.getTelemetry(any())).thenReturn(Optional.of(mockTelemetry));
+        List<TelemetryPlugin> telemetryPlugins = List.of(telemetryPlugin);
+
+        TelemetryModule telemetryModule = new TelemetryModule(telemetryPlugins, any());
+
+        assertTrue(telemetryModule.getTelemetry().isPresent());
+        assertEquals(mockTelemetry, telemetryModule.getTelemetry().get());
+    }
+
+    public void testGetTelemetryWithMultipleInstalledPlugins() {
+        TelemetryPlugin telemetryPlugin1 = mock(TelemetryPlugin.class);
+        TelemetryPlugin telemetryPlugin2 = mock(TelemetryPlugin.class);
+        when(telemetryPlugin1.getName()).thenReturn("otel");
+        Telemetry mockTelemetry1 = mock(Telemetry.class);
+        Telemetry mockTelemetry2 = mock(Telemetry.class);
+
+        when(telemetryPlugin1.getTelemetry(any())).thenReturn(Optional.of(mockTelemetry1));
+        when(telemetryPlugin2.getTelemetry(any())).thenReturn(Optional.of(mockTelemetry2));
+
+        List<TelemetryPlugin> telemetryPlugins = List.of(telemetryPlugin1, telemetryPlugin2);
+
+        try {
+            TelemetryModule telemetryModule = new TelemetryModule(telemetryPlugins, any());
+        } catch (Exception e) {
+            assertEquals("Cannot register more than one telemetry", e.getMessage());
+        }
+
+    }
+
+    public void testGetTelemetryWithNoPlugins() {
+        TelemetryPlugin telemetryPlugin = mock(TelemetryPlugin.class);
+        when(telemetryPlugin.getName()).thenReturn("otel");
+        TelemetryModule telemetryModule = new TelemetryModule(List.of(telemetryPlugin), any());
+
+        assertFalse(telemetryModule.getTelemetry().isPresent());
+
+    }
+
+}
diff --git a/server/src/test/java/org/opensearch/telemetry/metrics/MetricsRegistryFactoryTests.java b/server/src/test/java/org/opensearch/telemetry/metrics/MetricsRegistryFactoryTests.java
new file mode 100644
index 0000000000000..5d5ea62dd161e
--- /dev/null
+++ b/server/src/test/java/org/opensearch/telemetry/metrics/MetricsRegistryFactoryTests.java
@@ -0,0 +1,71 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.metrics;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.metrics.noop.NoopCounter;
+import org.opensearch.telemetry.metrics.noop.NoopMetricsRegistry;
+import org.opensearch.telemetry.tracing.TracingTelemetry;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class MetricsRegistryFactoryTests extends OpenSearchTestCase {
+
+    private MetricsRegistryFactory metricsRegistryFactory;
+
+    @After
+    public void close() {
+        metricsRegistryFactory.close();
+    }
+
+    public void testGetMeterRegistryWithUnavailableMetricsTelemetry() {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), false).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(mockTelemetry.getTracingTelemetry()).thenReturn(mock(TracingTelemetry.class));
+        metricsRegistryFactory = new MetricsRegistryFactory(telemetrySettings, Optional.empty());
+
+        MetricsRegistry metricsRegistry = metricsRegistryFactory.getMetricsRegistry();
+
+        assertTrue(metricsRegistry instanceof NoopMetricsRegistry);
+        assertTrue(metricsRegistry.createCounter("test", "test", "test") == NoopCounter.INSTANCE);
+        assertTrue(metricsRegistry.createUpDownCounter("test", "test", "test") == NoopCounter.INSTANCE);
+    }
+
+    public void testGetMetricsWithAvailableMetricsTelemetry() {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(mockTelemetry.getMetricsTelemetry()).thenReturn(mock(MetricsTelemetry.class));
+        metricsRegistryFactory = new MetricsRegistryFactory(telemetrySettings, Optional.of(mockTelemetry));
+
+        MetricsRegistry metricsRegistry = metricsRegistryFactory.getMetricsRegistry();
+        assertTrue(metricsRegistry instanceof DefaultMetricsRegistry);
+
+    }
+
+    private Set<Setting<?>> getClusterSettings() {
+        Set<Setting<?>> allTracerSettings = new HashSet<>();
+        ClusterSettings.FEATURE_FLAGGED_CLUSTER_SETTINGS.get(List.of(FeatureFlags.TELEMETRY)).stream().forEach((allTracerSettings::add));
+        return allTracerSettings;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/telemetry/tracing/SpanBuilderTests.java b/server/src/test/java/org/opensearch/telemetry/tracing/SpanBuilderTests.java
new file mode 100644
index 0000000000000..b4183412cdf02
--- /dev/null
+++ b/server/src/test/java/org/opensearch/telemetry/tracing/SpanBuilderTests.java
@@ -0,0 +1,158 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.network.NetworkAddress;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.http.HttpRequest;
+import org.opensearch.http.HttpResponse;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.transport.Transport;
+import org.opensearch.transport.TransportException;
+import org.opensearch.transport.TransportRequest;
+import org.opensearch.transport.TransportRequestOptions;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+public class SpanBuilderTests extends OpenSearchTestCase {
+
+    public void testHttpRequestContext() {
+        HttpRequest httpRequest = createHttpRequest();
+        SpanCreationContext context = SpanBuilder.from(httpRequest);
+        Attributes attributes = context.getAttributes();
+        assertEquals("GET /_test", context.getSpanName());
+        assertEquals("true", attributes.getAttributesMap().get(AttributeNames.TRACE));
+        assertEquals("GET", attributes.getAttributesMap().get(AttributeNames.HTTP_METHOD));
+        assertEquals("HTTP_1_0", attributes.getAttributesMap().get(AttributeNames.HTTP_PROTOCOL_VERSION));
+        assertEquals("/_test", attributes.getAttributesMap().get(AttributeNames.HTTP_URI));
+    }
+
+    public void testRestRequestContext() {
+        RestRequest restRequest = RestRequest.request(null, createHttpRequest(), null);
+        SpanCreationContext context = SpanBuilder.from(restRequest);
+        Attributes attributes = context.getAttributes();
+        assertEquals("GET /_test", context.getSpanName());
+        assertEquals("/_test", attributes.getAttributesMap().get(AttributeNames.REST_REQ_RAW_PATH));
+        assertNotNull(attributes.getAttributesMap().get(AttributeNames.REST_REQ_ID));
+    }
+
+    public void testRestRequestContextForNull() {
+        SpanCreationContext context = SpanBuilder.from((RestRequest) null);
+        assertEquals("rest_request", context.getSpanName());
+        assertEquals(Attributes.EMPTY, context.getAttributes());
+    }
+
+    public void testTransportContext() {
+        String action = "test-action";
+        Transport.Connection connection = createTransportConnection();
+        SpanCreationContext context = SpanBuilder.from(action, connection);
+        Attributes attributes = context.getAttributes();
+        assertEquals(action + " " + NetworkAddress.format(TransportAddress.META_ADDRESS), context.getSpanName());
+        assertEquals(connection.getNode().getHostAddress(), attributes.getAttributesMap().get(AttributeNames.TRANSPORT_TARGET_HOST));
+    }
+
+    private static Transport.Connection createTransportConnection() {
+        return new Transport.Connection() {
+            @Override
+            public DiscoveryNode getNode() {
+                return new DiscoveryNode("local", new TransportAddress(TransportAddress.META_ADDRESS, 9200), Version.V_2_0_0);
+            }
+
+            @Override
+            public void sendRequest(long requestId, String action, TransportRequest request, TransportRequestOptions options)
+                throws IOException, TransportException {
+
+            }
+
+            @Override
+            public void addCloseListener(ActionListener<Void> listener) {
+
+            }
+
+            @Override
+            public boolean isClosed() {
+                return false;
+            }
+
+            @Override
+            public void close() {
+
+            }
+        };
+    }
+
+    private static HttpRequest createHttpRequest() {
+        return new HttpRequest() {
+            @Override
+            public RestRequest.Method method() {
+                return RestRequest.Method.GET;
+            }
+
+            @Override
+            public String uri() {
+                return "/_test";
+            }
+
+            @Override
+            public BytesReference content() {
+                return null;
+            }
+
+            @Override
+            public Map<String, List<String>> getHeaders() {
+                return Map.of("trace", Arrays.asList("true"));
+            }
+
+            @Override
+            public List<String> strictCookies() {
+                return null;
+            }
+
+            @Override
+            public HttpVersion protocolVersion() {
+                return HttpVersion.HTTP_1_0;
+            }
+
+            @Override
+            public HttpRequest removeHeader(String header) {
+                return null;
+            }
+
+            @Override
+            public HttpResponse createResponse(RestStatus status, BytesReference content) {
+                return null;
+            }
+
+            @Override
+            public Exception getInboundException() {
+                return null;
+            }
+
+            @Override
+            public void release() {
+
+            }
+
+            @Override
+            public HttpRequest releaseAndCopy() {
+                return null;
+            }
+        };
+    }
+}
diff --git a/server/src/test/java/org/opensearch/telemetry/tracing/TracerFactoryTests.java b/server/src/test/java/org/opensearch/telemetry/tracing/TracerFactoryTests.java
new file mode 100644
index 0000000000000..b27f888eaf502
--- /dev/null
+++ b/server/src/test/java/org/opensearch/telemetry/tracing/TracerFactoryTests.java
@@ -0,0 +1,91 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.telemetry.tracing.noop.NoopSpan;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+import org.junit.After;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TracerFactoryTests extends OpenSearchTestCase {
+
+    private TracerFactory tracerFactory;
+
+    @After
+    public void close() {
+        tracerFactory.close();
+    }
+
+    public void testGetTracerWithUnavailableTracingTelemetryReturnsNoopTracer() {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), false).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(mockTelemetry.getTracingTelemetry()).thenReturn(mock(TracingTelemetry.class));
+        tracerFactory = new TracerFactory(telemetrySettings, Optional.empty(), new ThreadContext(Settings.EMPTY));
+
+        Tracer tracer = tracerFactory.getTracer();
+
+        assertTrue(tracer instanceof NoopTracer);
+        assertTrue(tracer.startSpan(SpanCreationContext.internal().name("foo").attributes(Attributes.EMPTY)) == NoopSpan.INSTANCE);
+        assertTrue(tracer.startScopedSpan(SpanCreationContext.internal().name("foo").attributes(Attributes.EMPTY)) == ScopedSpan.NO_OP);
+        assertTrue(tracer.startScopedSpan(SpanCreationContext.internal().name("foo").attributes(Attributes.EMPTY)) == ScopedSpan.NO_OP);
+        assertTrue(
+            tracer.withSpanInScope(
+                tracer.startSpan(SpanCreationContext.internal().name("foo").attributes(Attributes.EMPTY))
+            ) == SpanScope.NO_OP
+        );
+    }
+
+    public void testGetTracerWithUnavailableTracingTelemetry() {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), false).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(mockTelemetry.getTracingTelemetry()).thenReturn(mock(TracingTelemetry.class));
+        tracerFactory = new TracerFactory(telemetrySettings, Optional.empty(), new ThreadContext(Settings.EMPTY));
+
+        Tracer tracer = tracerFactory.getTracer();
+
+        assertTrue(tracer instanceof NoopTracer);
+        assertTrue(tracer.startScopedSpan(SpanCreationContext.internal().name("foo").attributes(Attributes.EMPTY)) == ScopedSpan.NO_OP);
+    }
+
+    public void testGetTracerWithAvailableTracingTelemetryReturnsWrappedTracer() {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        Telemetry mockTelemetry = mock(Telemetry.class);
+        when(mockTelemetry.getTracingTelemetry()).thenReturn(mock(TracingTelemetry.class));
+        tracerFactory = new TracerFactory(telemetrySettings, Optional.of(mockTelemetry), new ThreadContext(Settings.EMPTY));
+
+        Tracer tracer = tracerFactory.getTracer();
+        assertTrue(tracer instanceof WrappedTracer);
+
+    }
+
+    private Set<Setting<?>> getClusterSettings() {
+        Set<Setting<?>> allTracerSettings = new HashSet<>();
+        ClusterSettings.FEATURE_FLAGGED_CLUSTER_SETTINGS.get(List.of(FeatureFlags.TELEMETRY)).stream().forEach((allTracerSettings::add));
+        return allTracerSettings;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/telemetry/tracing/WrappedTracerTests.java b/server/src/test/java/org/opensearch/telemetry/tracing/WrappedTracerTests.java
new file mode 100644
index 0000000000000..43e0cb8e44439
--- /dev/null
+++ b/server/src/test/java/org/opensearch/telemetry/tracing/WrappedTracerTests.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+public class WrappedTracerTests extends OpenSearchTestCase {
+
+    public void testStartSpanWithTracingDisabledInvokesNoopTracer() throws Exception {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), false).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        DefaultTracer mockDefaultTracer = mock(DefaultTracer.class);
+
+        try (WrappedTracer wrappedTracer = new WrappedTracer(telemetrySettings, mockDefaultTracer)) {
+            SpanCreationContext spanCreationContext = SpanCreationContext.internal().name("foo");
+            wrappedTracer.startSpan(spanCreationContext);
+            assertTrue(wrappedTracer.getDelegateTracer() instanceof NoopTracer);
+            verify(mockDefaultTracer, never()).startSpan(SpanCreationContext.internal().name("foo"));
+        }
+    }
+
+    public void testStartSpanWithTracingEnabledInvokesDefaultTracer() throws Exception {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        DefaultTracer mockDefaultTracer = mock(DefaultTracer.class);
+
+        try (WrappedTracer wrappedTracer = new WrappedTracer(telemetrySettings, mockDefaultTracer)) {
+            SpanCreationContext spanCreationContext = SpanCreationContext.internal().name("foo");
+            wrappedTracer.startSpan(spanCreationContext);
+
+            assertTrue(wrappedTracer.getDelegateTracer() instanceof DefaultTracer);
+            verify(mockDefaultTracer).startSpan(eq(spanCreationContext));
+        }
+    }
+
+    public void testStartSpanWithTracingEnabledInvokesDefaultTracerWithAttr() throws Exception {
+        Settings settings = Settings.builder().put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true).build();
+        TelemetrySettings telemetrySettings = new TelemetrySettings(settings, new ClusterSettings(settings, getClusterSettings()));
+        DefaultTracer mockDefaultTracer = mock(DefaultTracer.class);
+        Attributes attributes = Attributes.create().addAttribute("key", "value");
+        try (WrappedTracer wrappedTracer = new WrappedTracer(telemetrySettings, mockDefaultTracer)) {
+            SpanCreationContext spanCreationContext = SpanCreationContext.internal().name("foo");
+            wrappedTracer.startSpan(spanCreationContext);
+
+            assertTrue(wrappedTracer.getDelegateTracer() instanceof DefaultTracer);
+            verify(mockDefaultTracer).startSpan(spanCreationContext);
+        }
+    }
+
+    public void testClose() throws IOException {
+        DefaultTracer mockDefaultTracer = mock(DefaultTracer.class);
+        WrappedTracer wrappedTracer = new WrappedTracer(null, mockDefaultTracer);
+
+        wrappedTracer.close();
+
+        verify(mockDefaultTracer).close();
+    }
+
+    private Set<Setting<?>> getClusterSettings() {
+        Set<Setting<?>> allTracerSettings = new HashSet<>();
+        ClusterSettings.FEATURE_FLAGGED_CLUSTER_SETTINGS.get(List.of(FeatureFlags.TELEMETRY)).stream().forEach((allTracerSettings::add));
+        return allTracerSettings;
+    }
+}
diff --git a/server/src/test/java/org/opensearch/test/NoopDiscovery.java b/server/src/test/java/org/opensearch/test/NoopDiscovery.java
index c1127aed95c1c..42d3f1887ab4d 100644
--- a/server/src/test/java/org/opensearch/test/NoopDiscovery.java
+++ b/server/src/test/java/org/opensearch/test/NoopDiscovery.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.test;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleListener;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.discovery.Discovery;
 import org.opensearch.discovery.DiscoveryStats;
 
diff --git a/server/src/test/java/org/opensearch/test/geo/RandomShapeGenerator.java b/server/src/test/java/org/opensearch/test/geo/RandomShapeGenerator.java
index 2772f9d45f618..bdce3fc62df09 100644
--- a/server/src/test/java/org/opensearch/test/geo/RandomShapeGenerator.java
+++ b/server/src/test/java/org/opensearch/test/geo/RandomShapeGenerator.java
@@ -33,10 +33,8 @@
 package org.opensearch.test.geo;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.opensearch.OpenSearchException;
-import org.locationtech.jts.algorithm.ConvexHull;
-import org.locationtech.jts.geom.Coordinate;
-import org.locationtech.jts.geom.Geometry;
 import org.opensearch.common.geo.builders.CoordinatesBuilder;
 import org.opensearch.common.geo.builders.GeometryCollectionBuilder;
 import org.opensearch.common.geo.builders.LineStringBuilder;
@@ -47,6 +45,12 @@
 import org.opensearch.common.geo.builders.ShapeBuilder;
 import org.opensearch.search.geo.GeoShapeQueryTests;
 import org.junit.Assert;
+
+import java.util.Random;
+
+import org.locationtech.jts.algorithm.ConvexHull;
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
 import org.locationtech.spatial4j.context.jts.JtsSpatialContext;
 import org.locationtech.spatial4j.distance.DistanceUtils;
 import org.locationtech.spatial4j.exception.InvalidShapeException;
@@ -54,8 +58,6 @@
 import org.locationtech.spatial4j.shape.Rectangle;
 import org.locationtech.spatial4j.shape.impl.Range;
 
-import java.util.Random;
-
 import static org.locationtech.spatial4j.shape.SpatialRelation.CONTAINS;
 
 /**
diff --git a/server/src/test/java/org/opensearch/test/hamcrest/OpenSearchGeoAssertions.java b/server/src/test/java/org/opensearch/test/hamcrest/OpenSearchGeoAssertions.java
index 96a5acf7e0b3d..74332edc010c7 100644
--- a/server/src/test/java/org/opensearch/test/hamcrest/OpenSearchGeoAssertions.java
+++ b/server/src/test/java/org/opensearch/test/hamcrest/OpenSearchGeoAssertions.java
@@ -36,11 +36,16 @@
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.geo.parsers.ShapeParser;
 import org.opensearch.common.unit.DistanceUnit;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.geometry.Line;
 import org.opensearch.geometry.MultiLine;
 import org.hamcrest.Matcher;
 import org.junit.Assert;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.Geometry;
 import org.locationtech.jts.geom.LineString;
@@ -54,10 +59,6 @@
 import org.locationtech.spatial4j.shape.jts.JtsGeometry;
 import org.locationtech.spatial4j.shape.jts.JtsPoint;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import static org.hamcrest.Matchers.instanceOf;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
diff --git a/server/src/test/java/org/opensearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java b/server/src/test/java/org/opensearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
index 1092bc4f8f47c..605050fffab4e 100644
--- a/server/src/test/java/org/opensearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
+++ b/server/src/test/java/org/opensearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.search.aggregations.Aggregation;
 import org.opensearch.search.aggregations.bucket.terms.SignificantTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
@@ -48,12 +48,12 @@
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
 
+import static org.opensearch.search.aggregations.AggregationBuilders.significantTerms;
+import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.OpenSearchIntegTestCase.client;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.equalTo;
-import static org.opensearch.search.aggregations.AggregationBuilders.significantTerms;
-import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 
 public class SharedSignificantTermsTestMethods {
     public static final String INDEX_NAME = "testidx";
@@ -99,7 +99,7 @@ public static void index01Docs(String type, String settings, OpenSearchIntegTest
         }
         assertAcked(
             testCase.prepareCreate(INDEX_NAME)
-                .setSettings(settings, XContentType.JSON)
+                .setSettings(settings, MediaTypeRegistry.JSON)
                 .setMapping("text", textMappings, CLASS_FIELD, "type=keyword")
         );
         String[] gb = { "0", "1" };
@@ -113,4 +113,41 @@ public static void index01Docs(String type, String settings, OpenSearchIntegTest
         indexRequestBuilderList.add(client().prepareIndex(INDEX_NAME).setId("7").setSource(TEXT_FIELD, "0", CLASS_FIELD, "0"));
         testCase.indexRandom(true, false, indexRequestBuilderList);
     }
+
+    public static void index01DocsWithRouting(String type, String settings, OpenSearchIntegTestCase testCase) throws ExecutionException,
+        InterruptedException {
+        String textMappings = "type=" + type;
+        if (type.equals("text")) {
+            textMappings += ",fielddata=true";
+        }
+        assertAcked(
+            testCase.prepareCreate(INDEX_NAME)
+                .setSettings(settings, MediaTypeRegistry.JSON)
+                .setMapping("text", textMappings, CLASS_FIELD, "type=keyword")
+        );
+        String[] gb = { "0", "1" };
+        List<IndexRequestBuilder> indexRequestBuilderList = new ArrayList<>();
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("1").setSource(TEXT_FIELD, "1", CLASS_FIELD, "1").setRouting("0")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("2").setSource(TEXT_FIELD, "1", CLASS_FIELD, "1").setRouting("0")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("3").setSource(TEXT_FIELD, "0", CLASS_FIELD, "0").setRouting("0")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("4").setSource(TEXT_FIELD, "0", CLASS_FIELD, "0").setRouting("1")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("5").setSource(TEXT_FIELD, gb, CLASS_FIELD, "1").setRouting("1")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("6").setSource(TEXT_FIELD, gb, CLASS_FIELD, "0").setRouting("0")
+        );
+        indexRequestBuilderList.add(
+            client().prepareIndex(INDEX_NAME).setId("7").setSource(TEXT_FIELD, "0", CLASS_FIELD, "0").setRouting("0")
+        );
+        testCase.indexRandom(true, false, indexRequestBuilderList);
+    }
 }
diff --git a/server/src/test/java/org/opensearch/threadpool/FixedThreadPoolTests.java b/server/src/test/java/org/opensearch/threadpool/FixedThreadPoolTests.java
index 52b4a4ce6a231..3cba803e84e68 100644
--- a/server/src/test/java/org/opensearch/threadpool/FixedThreadPoolTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/FixedThreadPoolTests.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.threadpool.ThreadPool.Names;
 
 import java.util.concurrent.CountDownLatch;
diff --git a/server/src/test/java/org/opensearch/threadpool/ScalingThreadPoolTests.java b/server/src/test/java/org/opensearch/threadpool/ScalingThreadPoolTests.java
index a3a7cbecc6958..92bd15d818bca 100644
--- a/server/src/test/java/org/opensearch/threadpool/ScalingThreadPoolTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/ScalingThreadPoolTests.java
@@ -132,6 +132,10 @@ private int expectedSize(final String threadPoolName, final int numberOfProcesso
         sizes.put(ThreadPool.Names.SNAPSHOT, ThreadPool::halfAllocatedProcessorsMaxFive);
         sizes.put(ThreadPool.Names.FETCH_SHARD_STARTED, ThreadPool::twiceAllocatedProcessors);
         sizes.put(ThreadPool.Names.FETCH_SHARD_STORE, ThreadPool::twiceAllocatedProcessors);
+        sizes.put(ThreadPool.Names.TRANSLOG_TRANSFER, ThreadPool::halfAllocatedProcessorsMaxTen);
+        sizes.put(ThreadPool.Names.TRANSLOG_SYNC, n -> 4 * n);
+        sizes.put(ThreadPool.Names.REMOTE_PURGE, ThreadPool::halfAllocatedProcessorsMaxFive);
+        sizes.put(ThreadPool.Names.REMOTE_REFRESH_RETRY, ThreadPool::halfAllocatedProcessorsMaxTen);
         return sizes.get(threadPoolName).apply(numberOfProcessors);
     }
 
diff --git a/server/src/test/java/org/opensearch/threadpool/ScheduleWithFixedDelayTests.java b/server/src/test/java/org/opensearch/threadpool/ScheduleWithFixedDelayTests.java
index 0e5dc23bf8b5c..92262b022ac07 100644
--- a/server/src/test/java/org/opensearch/threadpool/ScheduleWithFixedDelayTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/ScheduleWithFixedDelayTests.java
@@ -36,12 +36,12 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.BaseFuture;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
 import org.opensearch.node.Node;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.Scheduler.Cancellable;
-import org.opensearch.threadpool.ThreadPool.Names;
 import org.opensearch.threadpool.Scheduler.ReschedulingRunnable;
+import org.opensearch.threadpool.ThreadPool.Names;
 import org.junit.After;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/threadpool/ThreadPoolSerializationTests.java b/server/src/test/java/org/opensearch/threadpool/ThreadPoolSerializationTests.java
index 6623cb0e18819..0276f3846214d 100644
--- a/server/src/test/java/org/opensearch/threadpool/ThreadPoolSerializationTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/ThreadPoolSerializationTests.java
@@ -32,15 +32,15 @@
 package org.opensearch.threadpool;
 
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.SizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/threadpool/ThreadPoolStatsTests.java b/server/src/test/java/org/opensearch/threadpool/ThreadPoolStatsTests.java
index 30db8b74289ce..869d7ec59b081 100644
--- a/server/src/test/java/org/opensearch/threadpool/ThreadPoolStatsTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/ThreadPoolStatsTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.threadpool;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -51,13 +51,13 @@
 public class ThreadPoolStatsTests extends OpenSearchTestCase {
     public void testThreadPoolStatsSort() throws IOException {
         List<ThreadPoolStats.Stats> stats = new ArrayList<>();
-        stats.add(new ThreadPoolStats.Stats("z", -1, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("m", 3, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("m", 1, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("d", -1, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("m", 2, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("t", -1, 0, 0, 0, 0, 0L));
-        stats.add(new ThreadPoolStats.Stats("a", -1, 0, 0, 0, 0, 0L));
+        stats.add(new ThreadPoolStats.Stats("z", -1, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("m", 3, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("m", 1, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("d", -1, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("m", 2, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("t", -1, 0, 0, 0, 0, 0L, 0L));
+        stats.add(new ThreadPoolStats.Stats("a", -1, 0, 0, 0, 0, 0L, 0L));
 
         List<ThreadPoolStats.Stats> copy = new ArrayList<>(stats);
         Collections.sort(copy);
@@ -79,14 +79,14 @@ public void testThreadPoolStatsToXContent() throws IOException {
         try (BytesStreamOutput os = new BytesStreamOutput()) {
 
             List<ThreadPoolStats.Stats> stats = new ArrayList<>();
-            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.SEARCH, -1, 0, 0, 0, 0, 0L));
-            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.WARMER, -1, 0, 0, 0, 0, 0L));
-            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.GENERIC, -1, 0, 0, 0, 0, 0L));
-            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.FORCE_MERGE, -1, 0, 0, 0, 0, 0L));
-            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.SAME, -1, 0, 0, 0, 0, 0L));
+            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.SEARCH, -1, 0, 0, 0, 0, 0L, 0L));
+            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.WARMER, -1, 0, 0, 0, 0, 0L, -1L));
+            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.GENERIC, -1, 0, 0, 0, 0, 0L, -1L));
+            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.FORCE_MERGE, -1, 0, 0, 0, 0, 0L, -1L));
+            stats.add(new ThreadPoolStats.Stats(ThreadPool.Names.SAME, -1, 0, 0, 0, 0, 0L, -1L));
 
             ThreadPoolStats threadPoolStats = new ThreadPoolStats(stats);
-            try (XContentBuilder builder = new XContentBuilder(XContentType.JSON.xContent(), os)) {
+            try (XContentBuilder builder = new XContentBuilder(MediaTypeRegistry.JSON.xContent(), os)) {
                 builder.startObject();
                 threadPoolStats.toXContent(builder, ToXContent.EMPTY_PARAMS);
                 builder.endObject();
diff --git a/server/src/test/java/org/opensearch/threadpool/ThreadPoolTests.java b/server/src/test/java/org/opensearch/threadpool/ThreadPoolTests.java
index cd23e664d1e72..658de5ec49500 100644
--- a/server/src/test/java/org/opensearch/threadpool/ThreadPoolTests.java
+++ b/server/src/test/java/org/opensearch/threadpool/ThreadPoolTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.concurrent.CountDownLatch;
diff --git a/server/src/test/java/org/opensearch/transport/ClusterConnectionManagerTests.java b/server/src/test/java/org/opensearch/transport/ClusterConnectionManagerTests.java
index bf47fc2cc9b45..1d734a56ef189 100644
--- a/server/src/test/java/org/opensearch/transport/ClusterConnectionManagerTests.java
+++ b/server/src/test/java/org/opensearch/transport/ClusterConnectionManagerTests.java
@@ -33,12 +33,12 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 import org.junit.After;
@@ -58,8 +58,8 @@
 import java.util.concurrent.atomic.AtomicReference;
 
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 
 public class ClusterConnectionManagerTests extends OpenSearchTestCase {
diff --git a/server/src/test/java/org/opensearch/transport/CompressibleBytesOutputStreamTests.java b/server/src/test/java/org/opensearch/transport/CompressibleBytesOutputStreamTests.java
index 643b6665cd659..89018b7353e7c 100644
--- a/server/src/test/java/org/opensearch/transport/CompressibleBytesOutputStreamTests.java
+++ b/server/src/test/java/org/opensearch/transport/CompressibleBytesOutputStreamTests.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.compress.CompressorFactory;
-import org.opensearch.common.io.stream.BytesStream;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.BytesStream;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.compress.CompressorRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.EOFException;
@@ -56,7 +56,7 @@ public void testStreamWithoutCompression() throws IOException {
         // Closing compression stream does not close underlying stream
         stream.close();
 
-        assertFalse(CompressorFactory.COMPRESSOR.isCompressed(bytesRef));
+        assertFalse(CompressorRegistry.defaultCompressor().isCompressed(bytesRef));
 
         StreamInput streamInput = bytesRef.streamInput();
         byte[] actualBytes = new byte[expectedBytes.length];
@@ -83,9 +83,11 @@ public void testStreamWithCompression() throws IOException {
         BytesReference bytesRef = stream.materializeBytes();
         stream.close();
 
-        assertTrue(CompressorFactory.COMPRESSOR.isCompressed(bytesRef));
+        assertTrue(CompressorRegistry.defaultCompressor().isCompressed(bytesRef));
 
-        StreamInput streamInput = new InputStreamStreamInput(CompressorFactory.COMPRESSOR.threadLocalInputStream(bytesRef.streamInput()));
+        StreamInput streamInput = new InputStreamStreamInput(
+            CompressorRegistry.defaultCompressor().threadLocalInputStream(bytesRef.streamInput())
+        );
         byte[] actualBytes = new byte[expectedBytes.length];
         streamInput.readBytes(actualBytes, 0, expectedBytes.length);
 
@@ -108,7 +110,7 @@ public void testCompressionWithCallingMaterializeFails() throws IOException {
         stream.write(expectedBytes);
 
         StreamInput streamInput = new InputStreamStreamInput(
-            CompressorFactory.COMPRESSOR.threadLocalInputStream(bStream.bytes().streamInput())
+            CompressorRegistry.defaultCompressor().threadLocalInputStream(bStream.bytes().streamInput())
         );
         byte[] actualBytes = new byte[expectedBytes.length];
         EOFException e = expectThrows(EOFException.class, () -> streamInput.readBytes(actualBytes, 0, expectedBytes.length));
diff --git a/server/src/test/java/org/opensearch/transport/ConnectionProfileTests.java b/server/src/test/java/org/opensearch/transport/ConnectionProfileTests.java
index d6dc56204f5da..d3a20e9b68e34 100644
--- a/server/src/test/java/org/opensearch/transport/ConnectionProfileTests.java
+++ b/server/src/test/java/org/opensearch/transport/ConnectionProfileTests.java
@@ -44,8 +44,8 @@
 import java.util.HashSet;
 import java.util.List;
 
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.nonDataNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
 import static org.opensearch.test.NodeRoles.removeRoles;
 import static org.hamcrest.Matchers.equalTo;
 
@@ -240,7 +240,7 @@ public void testDefaultConnectionProfile() {
         assertEquals(TransportSettings.TRANSPORT_COMPRESS.get(Settings.EMPTY), profile.getCompressionEnabled());
         assertEquals(TransportSettings.PING_SCHEDULE.get(Settings.EMPTY), profile.getPingInterval());
 
-        profile = ConnectionProfile.buildDefaultConnectionProfile(nonMasterNode());
+        profile = ConnectionProfile.buildDefaultConnectionProfile(nonClusterManagerNode());
         assertEquals(12, profile.getNumConnections());
         assertEquals(1, profile.getNumConnectionsPerType(TransportRequestOptions.Type.PING));
         assertEquals(6, profile.getNumConnectionsPerType(TransportRequestOptions.Type.REG));
diff --git a/server/src/test/java/org/opensearch/transport/InboundAggregatorTests.java b/server/src/test/java/org/opensearch/transport/InboundAggregatorTests.java
index e9ffa4d478b22..2dd98a8efe2a3 100644
--- a/server/src/test/java/org/opensearch/transport/InboundAggregatorTests.java
+++ b/server/src/test/java/org/opensearch/transport/InboundAggregatorTests.java
@@ -33,14 +33,14 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.breaker.CircuitBreakingException;
 import org.opensearch.common.breaker.TestCircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.bytes.BytesArray;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.Before;
 
diff --git a/server/src/test/java/org/opensearch/transport/InboundDecoderTests.java b/server/src/test/java/org/opensearch/transport/InboundDecoderTests.java
index 9c78d039984e1..abde20cd4dcd1 100644
--- a/server/src/test/java/org/opensearch/transport/InboundDecoderTests.java
+++ b/server/src/test/java/org/opensearch/transport/InboundDecoderTests.java
@@ -34,12 +34,13 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.transport.TransportMessage;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 
diff --git a/server/src/test/java/org/opensearch/transport/InboundHandlerTests.java b/server/src/test/java/org/opensearch/transport/InboundHandlerTests.java
index 4076e7229ebf7..e002297911788 100644
--- a/server/src/test/java/org/opensearch/transport/InboundHandlerTests.java
+++ b/server/src/test/java/org/opensearch/transport/InboundHandlerTests.java
@@ -37,21 +37,22 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.InputStreamStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.tasks.TaskManager;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -63,6 +64,8 @@
 import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
@@ -88,7 +91,7 @@ public void setUp() throws Exception {
         super.setUp();
         taskManager = new TaskManager(Settings.EMPTY, threadPool, Collections.emptySet());
         channel = new FakeTcpChannel(randomBoolean(), buildNewFakeTransportAddress().address(), buildNewFakeTransportAddress().address()) {
-            public void sendMessage(BytesReference reference, org.opensearch.action.ActionListener<Void> listener) {
+            public void sendMessage(BytesReference reference, ActionListener<Void> listener) {
                 super.sendMessage(reference, listener);
                 if (listener != null) {
                     listener.onResponse(null);
@@ -115,7 +118,8 @@ public void sendMessage(BytesReference reference, org.opensearch.action.ActionLi
             handshaker,
             keepAlive,
             requestHandlers,
-            responseHandlers
+            responseHandlers,
+            NoopTracer.INSTANCE
         );
     }
 
@@ -254,8 +258,8 @@ public void testSendsErrorResponseToHandshakeFromCompatibleVersion() throws Exce
         );
         final InboundMessage requestMessage = unreadableInboundHandshake(remoteVersion, requestHeader);
         requestHeader.actionName = TransportHandshaker.HANDSHAKE_ACTION_NAME;
-        requestHeader.headers = Tuple.tuple(org.opensearch.common.collect.Map.of(), org.opensearch.common.collect.Map.of());
-        requestHeader.features = org.opensearch.common.collect.Set.of();
+        requestHeader.headers = Tuple.tuple(Map.of(), Map.of());
+        requestHeader.features = Set.of();
         handler.inboundMessage(channel, requestMessage);
 
         final BytesReference responseBytesReference = channel.getMessageCaptor().get();
@@ -294,8 +298,8 @@ public void testClosesChannelOnErrorInHandshakeWithIncompatibleVersion() throws
             );
             final InboundMessage requestMessage = unreadableInboundHandshake(remoteVersion, requestHeader);
             requestHeader.actionName = TransportHandshaker.HANDSHAKE_ACTION_NAME;
-            requestHeader.headers = Tuple.tuple(org.opensearch.common.collect.Map.of(), org.opensearch.common.collect.Map.of());
-            requestHeader.features = org.opensearch.common.collect.Set.of();
+            requestHeader.headers = Tuple.tuple(Map.of(), Map.of());
+            requestHeader.features = Set.of();
             handler.inboundMessage(channel, requestMessage);
             assertTrue(isClosed.get());
             assertNull(channel.getMessageCaptor().get());
@@ -332,7 +336,7 @@ public void testLogsSlowInboundProcessing() throws Exception {
             });
             requestHeader.actionName = TransportHandshaker.HANDSHAKE_ACTION_NAME;
             requestHeader.headers = Tuple.tuple(Collections.emptyMap(), Collections.emptyMap());
-            requestHeader.features = org.opensearch.common.collect.Set.of();
+            requestHeader.features = Set.of();
             handler.inboundMessage(channel, requestMessage);
             assertNotNull(channel.getMessageCaptor().get());
             mockAppender.assertAllExpectationsMatched();
diff --git a/server/src/test/java/org/opensearch/transport/InboundPipelineTests.java b/server/src/test/java/org/opensearch/transport/InboundPipelineTests.java
index 43de41bff69d4..ae4b537223394 100644
--- a/server/src/test/java/org/opensearch/transport/InboundPipelineTests.java
+++ b/server/src/test/java/org/opensearch/transport/InboundPipelineTests.java
@@ -33,12 +33,7 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.CircuitBreakingException;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
 import org.opensearch.common.breaker.TestCircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
@@ -47,7 +42,12 @@
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.common.util.io.Streams;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/transport/OutboundHandlerTests.java b/server/src/test/java/org/opensearch/transport/OutboundHandlerTests.java
index c4a25f7d80be7..ff99435f765d8 100644
--- a/server/src/test/java/org/opensearch/transport/OutboundHandlerTests.java
+++ b/server/src/test/java/org/opensearch/transport/OutboundHandlerTests.java
@@ -34,21 +34,22 @@
 
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.breaker.NoopCircuitBreaker;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.common.util.io.Streams;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/server/src/test/java/org/opensearch/transport/ProxyConnectionStrategyTests.java b/server/src/test/java/org/opensearch/transport/ProxyConnectionStrategyTests.java
index 1451e9466778b..1c9880ed14714 100644
--- a/server/src/test/java/org/opensearch/transport/ProxyConnectionStrategyTests.java
+++ b/server/src/test/java/org/opensearch/transport/ProxyConnectionStrategyTests.java
@@ -41,7 +41,8 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -82,7 +83,7 @@ public MockTransportService startTransport(final String id, final Version versio
             .put("node.name", id)
             .put(settings)
             .build();
-        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool);
+        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, NoopTracer.INSTANCE);
         try {
             newService.start();
             newService.acceptIncomingRequests();
@@ -99,7 +100,14 @@ public void testProxyStrategyWillOpenExpectedNumberOfConnectionsToAddress() {
         try (MockTransportService transport1 = startTransport("node1", Version.CURRENT)) {
             TransportAddress address1 = transport1.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -138,7 +146,14 @@ public void testProxyStrategyWillOpenNewConnectionsOnDisconnect() throws Excepti
             TransportAddress address1 = transport1.boundAddress().publishAddress();
             TransportAddress address2 = transport2.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -200,7 +215,14 @@ public void testConnectFailsWithIncompatibleNodes() {
         try (MockTransportService transport1 = startTransport("incompatible-node", incompatibleVersion)) {
             TransportAddress address1 = transport1.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -240,7 +262,14 @@ public void testClusterNameValidationPreventConnectingToDifferentClusters() thro
             TransportAddress address1 = transport1.boundAddress().publishAddress();
             TransportAddress address2 = transport2.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -303,7 +332,14 @@ public void testProxyStrategyWillResolveAddressesEachConnect() throws Exception
                 return address;
             };
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -338,7 +374,14 @@ public void testProxyStrategyWillNeedToBeRebuiltIfNumOfSocketsOrAddressesOrServe
         try (MockTransportService remoteTransport = startTransport("node1", Version.CURRENT)) {
             TransportAddress remoteAddress = remoteTransport.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -441,7 +484,14 @@ public void testServerNameAttributes() {
         try (MockTransportService transport1 = startTransport("node1", Version.CURRENT, bindSettings)) {
             TransportAddress address1 = transport1.boundAddress().publishAddress();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
diff --git a/server/src/test/java/org/opensearch/transport/RemoteClusterAwareClientTests.java b/server/src/test/java/org/opensearch/transport/RemoteClusterAwareClientTests.java
index 8e11c53e00b35..7595982837365 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteClusterAwareClientTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteClusterAwareClientTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsResponse;
@@ -41,6 +40,8 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -81,7 +82,14 @@ public void testSearchShards() throws Exception {
             Collections.shuffle(knownNodes, random());
             Settings.Builder builder = Settings.builder();
             builder.putList("cluster.remote.cluster1.seeds", seedTransport.getLocalDiscoNode().getAddress().toString());
-            try (MockTransportService service = MockTransportService.createNewService(builder.build(), Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    builder.build(),
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
 
@@ -121,7 +129,14 @@ public void testSearchShardsThreadContextHeader() {
             Collections.shuffle(knownNodes, random());
             Settings.Builder builder = Settings.builder();
             builder.putList("cluster.remote.cluster1.seeds", seedTransport.getLocalDiscoNode().getAddress().toString());
-            try (MockTransportService service = MockTransportService.createNewService(builder.build(), Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    builder.build(),
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
 
diff --git a/server/src/test/java/org/opensearch/transport/RemoteClusterClientTests.java b/server/src/test/java/org/opensearch/transport/RemoteClusterClientTests.java
index 94c535a5e20f5..f3b7f9916d460 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteClusterClientTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteClusterClientTests.java
@@ -39,6 +39,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.test.transport.MockTransportService;
@@ -79,14 +80,21 @@ public void testConnectAndExecuteRequest() throws Exception {
                 .put(onlyRole(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE))
                 .put("cluster.remote.test.seeds", remoteNode.getAddress().getAddress() + ":" + remoteNode.getAddress().getPort())
                 .build();
-            try (MockTransportService service = MockTransportService.createNewService(localSettings, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    localSettings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 // following two log lines added to investigate #41745, can be removed once issue is closed
                 logger.info("Start accepting incoming requests on local transport service");
                 service.acceptIncomingRequests();
                 logger.info("now accepting incoming requests on local transport");
                 RemoteClusterService remoteClusterService = service.getRemoteClusterService();
-                assertTrue(remoteClusterService.isRemoteNodeConnected("test", remoteNode));
+                assertBusy(() -> { assertTrue(remoteClusterService.isRemoteNodeConnected("test", remoteNode)); }, 10, TimeUnit.SECONDS);
                 Client client = remoteClusterService.getRemoteClusterClient(threadPool, "test");
                 ClusterStateResponse clusterStateResponse = client.admin().cluster().prepareState().execute().get();
                 assertNotNull(clusterStateResponse);
@@ -118,7 +126,14 @@ public void testEnsureWeReconnect() throws Exception {
                 .put(onlyRole(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE))
                 .put("cluster.remote.test.seeds", remoteNode.getAddress().getAddress() + ":" + remoteNode.getAddress().getPort())
                 .build();
-            try (MockTransportService service = MockTransportService.createNewService(localSettings, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    localSettings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 // this test is not perfect since we might reconnect concurrently but it will fail most of the time if we don't have
                 // the right calls in place in the RemoteAwareClient
@@ -147,7 +162,9 @@ public void testEnsureWeReconnect() throws Exception {
 
     public void testRemoteClusterServiceNotEnabled() {
         final Settings settings = removeRoles(Collections.singleton(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE));
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             final RemoteClusterService remoteClusterService = service.getRemoteClusterService();
diff --git a/server/src/test/java/org/opensearch/transport/RemoteClusterConnectionTests.java b/server/src/test/java/org/opensearch/transport/RemoteClusterConnectionTests.java
index 4d7137dc4133a..bb653439ec21e 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteClusterConnectionTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteClusterConnectionTests.java
@@ -34,7 +34,6 @@
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsAction;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsGroup;
 import org.opensearch.action.admin.cluster.shards.ClusterSearchShardsRequest;
@@ -51,21 +50,23 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
 import org.opensearch.search.aggregations.InternalAggregations;
 import org.opensearch.search.internal.InternalSearchResponse;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -126,7 +127,7 @@ public static MockTransportService startTransport(
         boolean success = false;
         final Settings s = Settings.builder().put(settings).put("node.name", id).build();
         ClusterName clusterName = ClusterName.CLUSTER_NAME_SETTING.get(s);
-        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, null);
+        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, NoopTracer.INSTANCE);
         try {
             newService.registerRequestHandler(
                 ClusterSearchShardsAction.NAME,
@@ -231,7 +232,14 @@ public void run() {
             };
             t.start();
 
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 CountDownLatch listenerCalled = new CountDownLatch(1);
@@ -280,7 +288,14 @@ public void testCloseWhileConcurrentlyConnecting() throws IOException, Interrupt
             List<String> seedNodes = addresses(seedNode1, seedNode);
             Collections.shuffle(seedNodes, random());
 
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 String clusterAlias = "test-cluster";
@@ -367,7 +382,14 @@ public void testGetConnectionInfo() throws Exception {
             List<String> seedNodes = addresses(node3, node1, node2);
             Collections.shuffle(seedNodes, random());
 
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 int maxNumConnections = randomIntBetween(1, 5);
@@ -463,14 +485,14 @@ public void testRenderConnectionInfoXContent() throws IOException {
                 "{\"test_cluster\":{\"connected\":true,\"mode\":\"sniff\",\"seeds\":[\"seed:1\",\"seed:2\"],"
                     + "\"num_nodes_connected\":2,\"max_connections_per_cluster\":3,\"initial_connect_timeout\":\"30m\","
                     + "\"skip_unavailable\":true}}",
-                Strings.toString(builder)
+                builder.toString()
             );
         } else {
             assertEquals(
                 "{\"test_cluster\":{\"connected\":true,\"mode\":\"proxy\",\"proxy_address\":\"seed:1\","
                     + "\"server_name\":\"the_server_name\",\"num_proxy_sockets_connected\":16,\"max_proxy_socket_connections\":18,"
                     + "\"initial_connect_timeout\":\"30m\",\"skip_unavailable\":true}}",
-                Strings.toString(builder)
+                builder.toString()
             );
         }
     }
@@ -480,7 +502,14 @@ public void testCollectNodes() throws Exception {
         try (MockTransportService seedTransport = startTransport("seed_node", knownNodes, Version.CURRENT)) {
             DiscoveryNode seedNode = seedTransport.getLocalDiscoNode();
             knownNodes.add(seedTransport.getLocalDiscoNode());
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 String clusterAlias = "test-cluster";
@@ -515,7 +544,14 @@ public void testNoChannelsExceptREG() throws Exception {
         try (MockTransportService seedTransport = startTransport("seed_node", knownNodes, Version.CURRENT)) {
             DiscoveryNode seedNode = seedTransport.getLocalDiscoNode();
             knownNodes.add(seedTransport.getLocalDiscoNode());
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 String clusterAlias = "test-cluster";
@@ -568,7 +604,14 @@ public void testConnectedNodesConcurrentAccess() throws IOException, Interrupted
             );
             Collections.shuffle(seedNodes, random());
 
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
 
@@ -645,7 +688,14 @@ public void testGetConnection() throws Exception {
 
             DiscoveryNode disconnectedNode = disconnectedTransport.getLocalNode();
 
-            try (MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
                 String clusterAlias = "test-cluster";
diff --git a/server/src/test/java/org/opensearch/transport/RemoteClusterServiceTests.java b/server/src/test/java/org/opensearch/transport/RemoteClusterServiceTests.java
index 75ba1fb56aa1d..449715189c881 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteClusterServiceTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteClusterServiceTests.java
@@ -32,18 +32,19 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.OriginalIndices;
 import org.opensearch.action.support.IndicesOptions;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.Strings;
 import org.opensearch.common.settings.AbstractScopedSettings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.Strings;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -59,11 +60,12 @@
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiFunction;
 
-import static org.opensearch.test.NodeRoles.masterOnlyNode;
-import static org.opensearch.test.NodeRoles.nonMasterNode;
+import static org.opensearch.test.NodeRoles.clusterManagerOnlyNode;
+import static org.opensearch.test.NodeRoles.nonClusterManagerNode;
 import static org.opensearch.test.NodeRoles.removeRoles;
 import static org.hamcrest.Matchers.either;
 import static org.hamcrest.Matchers.equalTo;
@@ -92,6 +94,20 @@ private MockTransportService startTransport(
         return RemoteClusterConnectionTests.startTransport(id, knownNodes, version, threadPool, settings);
     }
 
+    void initializeRemoteClusters(RemoteClusterService service) {
+        final PlainActionFuture<Void> future = new PlainActionFuture<>();
+        service.initializeRemoteClusters(future);
+        try {
+            future.get(10, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        } catch (TimeoutException ex) {
+            logger.warn("Timed out connecting to remote clusters");
+        } catch (Exception e) {
+            throw new IllegalStateException("failed to connect to remote clusters", e);
+        }
+    }
+
     public void testSettingsAreRegistered() {
         assertTrue(ClusterSettings.BUILT_IN_CLUSTER_SETTINGS.contains(RemoteClusterService.REMOTE_CLUSTER_SKIP_UNAVAILABLE));
         assertTrue(ClusterSettings.BUILT_IN_CLUSTER_SETTINGS.contains(RemoteClusterService.REMOTE_INITIAL_CONNECTION_TIMEOUT_SETTING));
@@ -147,7 +163,7 @@ public void testGroupClusterIndices() throws IOException {
                     Settings.EMPTY,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -157,7 +173,7 @@ public void testGroupClusterIndices() throws IOException {
                 builder.putList("cluster.remote.cluster_2.seeds", cluster2Seed.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(builder.build(), transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertTrue(service.isCrossClusterSearchEnabled());
                     assertTrue(service.isRemoteClusterRegistered("cluster_1"));
                     assertTrue(service.isRemoteClusterRegistered("cluster_2"));
@@ -218,7 +234,7 @@ public void testGroupIndices() throws IOException {
                     Settings.EMPTY,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -228,7 +244,7 @@ public void testGroupIndices() throws IOException {
                 builder.putList("cluster.remote.cluster_2.seeds", cluster2Seed.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(builder.build(), transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertTrue(service.isCrossClusterSearchEnabled());
                     assertTrue(service.isRemoteClusterRegistered("cluster_1"));
                     assertTrue(service.isRemoteClusterRegistered("cluster_2"));
@@ -311,7 +327,7 @@ public void testIncrementallyAddClusters() throws IOException {
                     Settings.EMPTY,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -321,7 +337,7 @@ public void testIncrementallyAddClusters() throws IOException {
                 builder.putList("cluster.remote.cluster_2.seeds", cluster2Seed.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(Settings.EMPTY, transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertFalse(service.isCrossClusterSearchEnabled());
                     Settings cluster1Settings = createSettings(
                         "cluster_1",
@@ -378,13 +394,18 @@ public void testDefaultPingSchedule() throws IOException {
             }
             Settings settings = settingsBuilder.build();
             try (
-                MockTransportService transportService = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)
+                MockTransportService transportService = MockTransportService.createNewService(
+                    settings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
             ) {
                 transportService.start();
                 transportService.acceptIncomingRequests();
                 try (RemoteClusterService service = new RemoteClusterService(settings, transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertTrue(service.isCrossClusterSearchEnabled());
                     service.validateAndUpdateRemoteCluster(
                         "cluster_1",
@@ -421,7 +442,7 @@ public void testCustomPingSchedule() throws IOException {
                     transportSettings,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -436,7 +457,7 @@ public void testCustomPingSchedule() throws IOException {
                     TimeValue.timeValueSeconds(randomIntBetween(1, 10));
                 builder.put("cluster.remote.cluster_2.transport.ping_schedule", pingSchedule2);
                 try (RemoteClusterService service = new RemoteClusterService(builder.build(), transportService)) {
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertTrue(service.isRemoteClusterRegistered("cluster_1"));
                     RemoteClusterConnection remoteClusterConnection1 = service.getRemoteClusterConnection("cluster_1");
                     assertEquals(pingSchedule1, remoteClusterConnection1.getConnectionManager().getConnectionProfile().getPingInterval());
@@ -459,7 +480,7 @@ public void testChangeSettings() throws Exception {
                     Settings.EMPTY,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -467,7 +488,7 @@ public void testChangeSettings() throws Exception {
                 Settings.Builder builder = Settings.builder();
                 builder.putList("cluster.remote.cluster_1.seeds", cluster1Seed.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(builder.build(), transportService)) {
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     RemoteClusterConnection remoteClusterConnection = service.getRemoteClusterConnection("cluster_1");
                     Settings.Builder settingsChange = Settings.builder();
                     TimeValue pingSchedule = TimeValue.timeValueSeconds(randomIntBetween(6, 8));
@@ -508,7 +529,12 @@ public void testRemoteNodeAttribute() throws IOException, InterruptedException {
             Collections.shuffle(knownNodes, random());
 
             try (
-                MockTransportService transportService = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)
+                MockTransportService transportService = MockTransportService.createNewService(
+                    settings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
             ) {
                 transportService.start();
                 transportService.acceptIncomingRequests();
@@ -517,7 +543,7 @@ public void testRemoteNodeAttribute() throws IOException, InterruptedException {
                 builder.putList("cluster.remote.cluster_2.seed", c2N1Node.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(settings, transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertFalse(service.isCrossClusterSearchEnabled());
 
                     final CountDownLatch firstLatch = new CountDownLatch(1);
@@ -552,12 +578,12 @@ public void testRemoteNodeAttribute() throws IOException, InterruptedException {
     public void testRemoteNodeRoles() throws IOException, InterruptedException {
         final Settings settings = Settings.EMPTY;
         final List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
-        final Settings data = nonMasterNode();
-        final Settings dedicatedMaster = masterOnlyNode();
+        final Settings data = nonClusterManagerNode();
+        final Settings dedicatedClusterManager = clusterManagerOnlyNode();
         try (
-            MockTransportService c1N1 = startTransport("cluster_1_node_1", knownNodes, Version.CURRENT, dedicatedMaster);
+            MockTransportService c1N1 = startTransport("cluster_1_node_1", knownNodes, Version.CURRENT, dedicatedClusterManager);
             MockTransportService c1N2 = startTransport("cluster_1_node_2", knownNodes, Version.CURRENT, data);
-            MockTransportService c2N1 = startTransport("cluster_2_node_1", knownNodes, Version.CURRENT, dedicatedMaster);
+            MockTransportService c2N1 = startTransport("cluster_2_node_1", knownNodes, Version.CURRENT, dedicatedClusterManager);
             MockTransportService c2N2 = startTransport("cluster_2_node_2", knownNodes, Version.CURRENT, data)
         ) {
             final DiscoveryNode c1N1Node = c1N1.getLocalDiscoNode();
@@ -571,7 +597,12 @@ public void testRemoteNodeRoles() throws IOException, InterruptedException {
             Collections.shuffle(knownNodes, random());
 
             try (
-                MockTransportService transportService = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)
+                MockTransportService transportService = MockTransportService.createNewService(
+                    settings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
             ) {
                 transportService.start();
                 transportService.acceptIncomingRequests();
@@ -580,7 +611,7 @@ public void testRemoteNodeRoles() throws IOException, InterruptedException {
                 builder.putList("cluster.remote.cluster_2.seed", c2N1Node.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(settings, transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertFalse(service.isCrossClusterSearchEnabled());
 
                     final CountDownLatch firstLatch = new CountDownLatch(1);
@@ -639,7 +670,12 @@ public void testCollectNodes() throws InterruptedException, IOException {
             Collections.shuffle(knownNodes_c2, random());
 
             try (
-                MockTransportService transportService = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)
+                MockTransportService transportService = MockTransportService.createNewService(
+                    settings,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
             ) {
                 transportService.start();
                 transportService.acceptIncomingRequests();
@@ -648,7 +684,7 @@ public void testCollectNodes() throws InterruptedException, IOException {
                 builder.putList("cluster.remote.cluster_2.seed", c2N1Node.getAddress().toString());
                 try (RemoteClusterService service = new RemoteClusterService(settings, transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertFalse(service.isCrossClusterSearchEnabled());
 
                     final CountDownLatch firstLatch = new CountDownLatch(1);
@@ -886,7 +922,7 @@ public void testReconnectWhenStrategySettingsUpdated() throws Exception {
                     Settings.EMPTY,
                     Version.CURRENT,
                     threadPool,
-                    null
+                    NoopTracer.INSTANCE
                 )
             ) {
                 transportService.start();
@@ -896,7 +932,7 @@ public void testReconnectWhenStrategySettingsUpdated() throws Exception {
                 builder.putList("cluster.remote.cluster_test.seeds", Collections.singletonList(node0.getAddress().toString()));
                 try (RemoteClusterService service = new RemoteClusterService(builder.build(), transportService)) {
                     assertFalse(service.isCrossClusterSearchEnabled());
-                    service.initializeRemoteClusters();
+                    initializeRemoteClusters(service);
                     assertTrue(service.isCrossClusterSearchEnabled());
 
                     final RemoteClusterConnection firstRemoteClusterConnection = service.getRemoteClusterConnection("cluster_test");
@@ -968,7 +1004,14 @@ public void testSkipUnavailable() {
             knownNodes.add(seedNode);
             Settings.Builder builder = Settings.builder();
             builder.putList("cluster.remote.cluster1.seeds", seedTransport.getLocalDiscoNode().getAddress().toString());
-            try (MockTransportService service = MockTransportService.createNewService(builder.build(), Version.CURRENT, threadPool, null)) {
+            try (
+                MockTransportService service = MockTransportService.createNewService(
+                    builder.build(),
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 service.start();
                 service.acceptIncomingRequests();
 
@@ -987,7 +1030,9 @@ public void testSkipUnavailable() {
 
     public void testRemoteClusterServiceNotEnabledGetRemoteClusterConnection() {
         final Settings settings = removeRoles(Collections.singleton(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE));
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             final IllegalArgumentException e = expectThrows(
@@ -1000,7 +1045,9 @@ public void testRemoteClusterServiceNotEnabledGetRemoteClusterConnection() {
 
     public void testRemoteClusterServiceNotEnabledGetCollectNodes() {
         final Settings settings = removeRoles(Collections.singleton(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE));
-        try (MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, null)) {
+        try (
+            MockTransportService service = MockTransportService.createNewService(settings, Version.CURRENT, threadPool, NoopTracer.INSTANCE)
+        ) {
             service.start();
             service.acceptIncomingRequests();
             final IllegalArgumentException e = expectThrows(
diff --git a/server/src/test/java/org/opensearch/transport/RemoteConnectionManagerTests.java b/server/src/test/java/org/opensearch/transport/RemoteConnectionManagerTests.java
index ccba66ff4c45e..c7f3944a2888b 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteConnectionManagerTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteConnectionManagerTests.java
@@ -32,11 +32,11 @@
 package org.opensearch.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.net.InetAddress;
diff --git a/server/src/test/java/org/opensearch/transport/RemoteConnectionStrategyTests.java b/server/src/test/java/org/opensearch/transport/RemoteConnectionStrategyTests.java
index 3888bcbdd3c99..e2acbcff3db16 100644
--- a/server/src/test/java/org/opensearch/transport/RemoteConnectionStrategyTests.java
+++ b/server/src/test/java/org/opensearch/transport/RemoteConnectionStrategyTests.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.mockito.Mockito.mock;
diff --git a/server/src/test/java/org/opensearch/transport/SniffConnectionStrategyTests.java b/server/src/test/java/org/opensearch/transport/SniffConnectionStrategyTests.java
index 1714f154036a5..c89a9d328b419 100644
--- a/server/src/test/java/org/opensearch/transport/SniffConnectionStrategyTests.java
+++ b/server/src/test/java/org/opensearch/transport/SniffConnectionStrategyTests.java
@@ -42,13 +42,14 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.AbstractScopedSettings;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.transport.MockTransportService;
@@ -105,7 +106,7 @@ public MockTransportService startTransport(
             .put(settings)
             .build();
         ClusterName clusterName = ClusterName.CLUSTER_NAME_SETTING.get(s);
-        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool);
+        MockTransportService newService = MockTransportService.createNewService(s, version, threadPool, NoopTracer.INSTANCE);
         try {
             newService.registerRequestHandler(
                 ClusterStateAction.NAME,
@@ -143,7 +144,14 @@ public void testSniffStrategyWillConnectToAndDiscoverNodes() {
             knownNodes.add(discoverableNode);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -192,7 +200,14 @@ public void testSniffStrategyWillResolveDiscoveryNodesEachConnect() throws Excep
                 return seedNode;
             };
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -240,7 +255,14 @@ public void testSniffStrategyWillConnectToMaxAllowedNodesAndOpenNewConnectionsOn
             knownNodes.add(discoverableNode2);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -297,7 +319,14 @@ public void testDiscoverWithSingleIncompatibleSeedNode() {
             knownNodes.add(discoverableNode);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -336,7 +365,14 @@ public void testConnectFailsWithIncompatibleNodes() {
             DiscoveryNode incompatibleSeedNode = incompatibleSeedTransport.getLocalNode();
             knownNodes.add(incompatibleSeedNode);
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -378,7 +414,14 @@ public void testFilterNodesWithNodePredicate() {
             DiscoveryNode rejectedNode = randomBoolean() ? seedNode : discoverableNode;
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -424,7 +467,14 @@ public void testConnectFailsIfNoConnectionsOpened() {
             knownNodes.add(discoverableNode);
             closedTransport.close();
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -474,7 +524,14 @@ public void testClusterNameValidationPreventConnectingToDifferentClusters() thro
             Collections.shuffle(knownNodes, random());
             Collections.shuffle(otherKnownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -542,7 +599,14 @@ public void testMultipleCallsToConnectEnsuresConnection() {
             knownNodes.add(discoverableNode);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -589,8 +653,18 @@ public void testConfiguredProxyAddressModeWillReplaceNodeAddress() {
         List<DiscoveryNode> knownNodes = new CopyOnWriteArrayList<>();
         try (
             MockTransportService accessible = startTransport("seed_node", knownNodes, Version.CURRENT);
-            MockTransportService unresponsive1 = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool);
-            MockTransportService unresponsive2 = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)
+            MockTransportService unresponsive1 = MockTransportService.createNewService(
+                Settings.EMPTY,
+                Version.CURRENT,
+                threadPool,
+                NoopTracer.INSTANCE
+            );
+            MockTransportService unresponsive2 = MockTransportService.createNewService(
+                Settings.EMPTY,
+                Version.CURRENT,
+                threadPool,
+                NoopTracer.INSTANCE
+            )
         ) {
             // We start in order to get a valid address + port, but do not start accepting connections as we
             // will not actually connect to these transports
@@ -616,7 +690,14 @@ public void testConfiguredProxyAddressModeWillReplaceNodeAddress() {
             knownNodes.add(discoverableNode);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -679,7 +760,14 @@ public void testSniffStrategyWillNeedToBeRebuiltIfNumOfConnectionsOrSeedsOrProxy
             knownNodes.add(discoverableNode);
             Collections.shuffle(knownNodes, random());
 
-            try (MockTransportService localService = MockTransportService.createNewService(Settings.EMPTY, Version.CURRENT, threadPool)) {
+            try (
+                MockTransportService localService = MockTransportService.createNewService(
+                    Settings.EMPTY,
+                    Version.CURRENT,
+                    threadPool,
+                    NoopTracer.INSTANCE
+                )
+            ) {
                 localService.start();
                 localService.acceptIncomingRequests();
 
@@ -743,24 +831,24 @@ public void testGetNodePredicateNodeRoles() {
             assertTrue(nodePredicate.test(all));
         }
         {
-            DiscoveryNode dataMaster = new DiscoveryNode(
+            DiscoveryNode dataClusterManager = new DiscoveryNode(
                 "id",
                 address,
                 Collections.emptyMap(),
                 new HashSet<>(Arrays.asList(DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)),
                 Version.CURRENT
             );
-            assertTrue(nodePredicate.test(dataMaster));
+            assertTrue(nodePredicate.test(dataClusterManager));
         }
         {
-            DiscoveryNode dedicatedMaster = new DiscoveryNode(
+            DiscoveryNode dedicatedClusterManager = new DiscoveryNode(
                 "id",
                 address,
                 Collections.emptyMap(),
                 new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)),
                 Version.CURRENT
             );
-            assertFalse(nodePredicate.test(dedicatedMaster));
+            assertFalse(nodePredicate.test(dedicatedClusterManager));
         }
         {
             DiscoveryNode dedicatedIngest = new DiscoveryNode(
@@ -773,14 +861,14 @@ public void testGetNodePredicateNodeRoles() {
             assertTrue(nodePredicate.test(dedicatedIngest));
         }
         {
-            DiscoveryNode masterIngest = new DiscoveryNode(
+            DiscoveryNode clusterManagerIngest = new DiscoveryNode(
                 "id",
                 address,
                 Collections.emptyMap(),
                 new HashSet<>(Arrays.asList(DiscoveryNodeRole.INGEST_ROLE, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)),
                 Version.CURRENT
             );
-            assertTrue(nodePredicate.test(masterIngest));
+            assertTrue(nodePredicate.test(clusterManagerIngest));
         }
         {
             DiscoveryNode dedicatedData = new DiscoveryNode(
@@ -855,14 +943,14 @@ public void testGetNodePredicatesCombination() {
         TransportAddress address = new TransportAddress(TransportAddress.META_ADDRESS, 0);
         Settings settings = Settings.builder().put("cluster.remote.node.attr", "gateway").build();
         Predicate<DiscoveryNode> nodePredicate = SniffConnectionStrategy.getNodePredicate(settings);
-        Set<DiscoveryNodeRole> dedicatedMasterRoles = new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
+        Set<DiscoveryNodeRole> dedicatedClusterManagerRoles = new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
         Set<DiscoveryNodeRole> allRoles = DiscoveryNodeRole.BUILT_IN_ROLES;
         {
             DiscoveryNode node = new DiscoveryNode(
                 "id",
                 address,
                 Collections.singletonMap("gateway", "true"),
-                dedicatedMasterRoles,
+                dedicatedClusterManagerRoles,
                 Version.CURRENT
             );
             assertFalse(nodePredicate.test(node));
@@ -872,7 +960,7 @@ public void testGetNodePredicatesCombination() {
                 "id",
                 address,
                 Collections.singletonMap("gateway", "false"),
-                dedicatedMasterRoles,
+                dedicatedClusterManagerRoles,
                 Version.CURRENT
             );
             assertFalse(nodePredicate.test(node));
@@ -882,7 +970,7 @@ public void testGetNodePredicatesCombination() {
                 "id",
                 address,
                 Collections.singletonMap("gateway", "false"),
-                dedicatedMasterRoles,
+                dedicatedClusterManagerRoles,
                 Version.CURRENT
             );
             assertFalse(nodePredicate.test(node));
diff --git a/server/src/test/java/org/opensearch/transport/TcpTransportTests.java b/server/src/test/java/org/opensearch/transport/TcpTransportTests.java
index 05d375579f3a5..7ab78cca7d615 100644
--- a/server/src/test/java/org/opensearch/transport/TcpTransportTests.java
+++ b/server/src/test/java/org/opensearch/transport/TcpTransportTests.java
@@ -38,17 +38,18 @@
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.component.Lifecycle;
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.common.lifecycle.Lifecycle;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
@@ -255,7 +256,8 @@ private void testDefaultSeedAddresses(final Settings settings, Matcher<Iterable<
                 new MockPageCacheRecycler(settings),
                 new NoneCircuitBreakerService(),
                 writableRegistry(),
-                new NetworkService(Collections.emptyList())
+                new NetworkService(Collections.emptyList()),
+                NoopTracer.INSTANCE
             ) {
 
                 @Override
diff --git a/server/src/test/java/org/opensearch/transport/TransportActionProxyTests.java b/server/src/test/java/org/opensearch/transport/TransportActionProxyTests.java
index 33f5a8d9e852f..dd2aefd2318f7 100644
--- a/server/src/test/java/org/opensearch/transport/TransportActionProxyTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportActionProxyTests.java
@@ -31,14 +31,16 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
+import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
@@ -84,7 +86,7 @@ public void tearDown() throws Exception {
     }
 
     private MockTransportService buildService(final Version version) {
-        MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, version, threadPool, null);
+        MockTransportService service = MockTransportService.createNewService(Settings.EMPTY, version, threadPool, NoopTracer.INSTANCE);
         service.start();
         service.acceptIncomingRequests();
         return service;
@@ -168,12 +170,9 @@ public void testException() throws InterruptedException {
         });
         TransportActionProxy.registerProxyAction(serviceB, "internal:test", SimpleTestResponse::new);
         serviceB.connectToNode(nodeC);
-        serviceC.registerRequestHandler(
-            "internal:test",
-            ThreadPool.Names.SAME,
-            SimpleTestRequest::new,
-            (request, channel, task) -> { throw new OpenSearchException("greetings from TS_C"); }
-        );
+        serviceC.registerRequestHandler("internal:test", ThreadPool.Names.SAME, SimpleTestRequest::new, (request, channel, task) -> {
+            throw new OpenSearchException("greetings from TS_C");
+        });
         TransportActionProxy.registerProxyAction(serviceC, "internal:test", SimpleTestResponse::new);
 
         CountDownLatch latch = new CountDownLatch(1);
diff --git a/server/src/test/java/org/opensearch/transport/TransportDecompressorTests.java b/server/src/test/java/org/opensearch/transport/TransportDecompressorTests.java
index 9bd746dd9e4c1..9811c0f690800 100644
--- a/server/src/test/java/org/opensearch/transport/TransportDecompressorTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportDecompressorTests.java
@@ -32,17 +32,17 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.compress.CompressorFactory;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.OutputStreamStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.compress.CompressorRegistry;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -53,7 +53,10 @@ public class TransportDecompressorTests extends OpenSearchTestCase {
     public void testSimpleCompression() throws IOException {
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             byte randomByte = randomByte();
-            try (OutputStream deflateStream = CompressorFactory.COMPRESSOR.threadLocalOutputStream(Streams.flushOnCloseStream(output))) {
+            try (
+                OutputStream deflateStream = CompressorRegistry.defaultCompressor()
+                    .threadLocalOutputStream(Streams.flushOnCloseStream(output))
+            ) {
                 deflateStream.write(randomByte);
             }
 
@@ -74,7 +77,7 @@ public void testMultiPageCompression() throws IOException {
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             try (
                 StreamOutput deflateStream = new OutputStreamStreamOutput(
-                    CompressorFactory.COMPRESSOR.threadLocalOutputStream(Streams.flushOnCloseStream(output))
+                    CompressorRegistry.defaultCompressor().threadLocalOutputStream(Streams.flushOnCloseStream(output))
                 )
             ) {
                 for (int i = 0; i < 10000; ++i) {
@@ -106,7 +109,7 @@ public void testIncrementalMultiPageCompression() throws IOException {
         try (BytesStreamOutput output = new BytesStreamOutput()) {
             try (
                 StreamOutput deflateStream = new OutputStreamStreamOutput(
-                    CompressorFactory.COMPRESSOR.threadLocalOutputStream(Streams.flushOnCloseStream(output))
+                    CompressorRegistry.defaultCompressor().threadLocalOutputStream(Streams.flushOnCloseStream(output))
                 )
             ) {
                 for (int i = 0; i < 10000; ++i) {
diff --git a/server/src/test/java/org/opensearch/transport/TransportHandshakerTests.java b/server/src/test/java/org/opensearch/transport/TransportHandshakerTests.java
index 9dbfec7bfe106..8223b973a7a62 100644
--- a/server/src/test/java/org/opensearch/transport/TransportHandshakerTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportHandshakerTests.java
@@ -35,9 +35,10 @@
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 
@@ -124,7 +125,7 @@ public void testHandshakeRequestFutureVersionsCompatibility() throws IOException
         TaskId.EMPTY_TASK_ID.writeTo(lengthCheckingHandshake);
         TaskId.EMPTY_TASK_ID.writeTo(futureHandshake);
         try (BytesStreamOutput internalMessage = new BytesStreamOutput()) {
-            Version.writeVersion(Version.CURRENT, internalMessage);
+            internalMessage.writeVersion(Version.CURRENT);
             lengthCheckingHandshake.writeBytesReference(internalMessage.bytes());
             internalMessage.write(new byte[1024]);
             futureHandshake.writeBytesReference(internalMessage.bytes());
diff --git a/server/src/test/java/org/opensearch/transport/TransportInfoTests.java b/server/src/test/java/org/opensearch/transport/TransportInfoTests.java
index 80311996db167..751f4786acf55 100644
--- a/server/src/test/java/org/opensearch/transport/TransportInfoTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportInfoTests.java
@@ -33,11 +33,11 @@
 package org.opensearch.transport;
 
 import org.opensearch.common.network.NetworkAddress;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/transport/TransportKeepAliveTests.java b/server/src/test/java/org/opensearch/transport/TransportKeepAliveTests.java
index 924826d1a7f07..bc8e351d75ac4 100644
--- a/server/src/test/java/org/opensearch/transport/TransportKeepAliveTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportKeepAliveTests.java
@@ -32,11 +32,11 @@
 package org.opensearch.transport;
 
 import org.opensearch.common.AsyncBiFunction;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 
@@ -48,8 +48,8 @@
 
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.eq;
-import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.same;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
diff --git a/server/src/test/java/org/opensearch/transport/TransportLoggerTests.java b/server/src/test/java/org/opensearch/transport/TransportLoggerTests.java
index 26f77d2fff9ee..05296e9308657 100644
--- a/server/src/test/java/org/opensearch/transport/TransportLoggerTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportLoggerTests.java
@@ -36,12 +36,12 @@
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.stats.ClusterStatsAction;
 import org.opensearch.action.admin.cluster.stats.ClusterStatsRequest;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.junit.annotations.TestLogging;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java b/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
index 755459ca96d90..3479102e553d4 100644
--- a/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.transport;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.action.ActionListener;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.common.SetOnce;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.concurrent.Phaser;
diff --git a/server/src/test/java/org/opensearch/transport/TransportServiceDeserializationFailureTests.java b/server/src/test/java/org/opensearch/transport/TransportServiceDeserializationFailureTests.java
index 8e11291e691e1..d10b4f26100cc 100644
--- a/server/src/test/java/org/opensearch/transport/TransportServiceDeserializationFailureTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportServiceDeserializationFailureTests.java
@@ -37,11 +37,13 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.tasks.TaskId;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskAwareRequest;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.ThreadPool;
@@ -81,7 +83,8 @@ protected void onSendRequest(long requestId, String action, TransportRequest req
             TransportService.NOOP_TRANSPORT_INTERCEPTOR,
             ignored -> localNode,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
 
         transportService.registerRequestHandler(
diff --git a/server/src/test/java/org/opensearch/transport/TransportServiceHandshakeTests.java b/server/src/test/java/org/opensearch/transport/TransportServiceHandshakeTests.java
index 8463d9268e760..9a884fd29d109 100644
--- a/server/src/test/java/org/opensearch/transport/TransportServiceHandshakeTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportServiceHandshakeTests.java
@@ -32,15 +32,19 @@
 
 package org.opensearch.transport;
 
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
+import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.transport.MockTransportService;
@@ -81,7 +85,8 @@ private NetworkHandle startServices(String nodeNameAndId, Settings settings, Ver
             new NetworkService(Collections.emptyList()),
             PageCacheRecycler.NON_RECYCLING_INSTANCE,
             new NamedWriteableRegistry(Collections.emptyList()),
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         );
         TransportService transportService = new MockTransportService(
             settings,
@@ -97,7 +102,8 @@ private NetworkHandle startServices(String nodeNameAndId, Settings settings, Ver
                 version
             ),
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         transportService.start();
         transportService.acceptIncomingRequests();
@@ -215,14 +221,43 @@ public void testNodeConnectWithDifferentNodeId() {
             emptySet(),
             handleB.discoveryNode.getVersion()
         );
-        ConnectTransportException ex = expectThrows(
-            ConnectTransportException.class,
-            () -> { handleA.transportService.connectToNode(discoveryNode, TestProfiles.LIGHT_PROFILE); }
-        );
+        ConnectTransportException ex = expectThrows(ConnectTransportException.class, () -> {
+            handleA.transportService.connectToNode(discoveryNode, TestProfiles.LIGHT_PROFILE);
+        });
         assertThat(ex.getMessage(), containsString("unexpected remote node"));
         assertFalse(handleA.transportService.nodeConnected(discoveryNode));
     }
 
+    public void testNodeConnectWithDifferentNodeIDSkipValidation() throws IllegalAccessException {
+        Settings settings = Settings.builder().put("cluster.name", "test").build();
+        NetworkHandle handleA = startServices("TS_A", settings, Version.CURRENT);
+        NetworkHandle handleB = startServices("TS_B", settings, Version.CURRENT);
+        DiscoveryNode discoveryNode = new DiscoveryNode(
+            randomAlphaOfLength(10),
+            handleB.discoveryNode.getAddress(),
+            emptyMap(),
+            emptySet(),
+            handleB.discoveryNode.getVersion()
+        );
+        try (MockLogAppender mockLogAppender = MockLogAppender.createForLoggers(LogManager.getLogger(TransportService.class))) {
+
+            mockLogAppender.addExpectation(
+                new MockLogAppender.SeenEventExpectation(
+                    "Validation Skipped",
+                    "org.opensearch.transport.TransportService",
+                    Level.INFO,
+                    "Connection validation was skipped"
+                )
+            );
+
+            handleA.transportService.connectToExtensionNode(discoveryNode, TestProfiles.LIGHT_PROFILE);
+
+            mockLogAppender.assertAllExpectationsMatched();
+
+            assertTrue(handleA.transportService.nodeConnected(discoveryNode));
+        }
+    }
+
     private static class NetworkHandle {
         private TransportService transportService;
         private DiscoveryNode discoveryNode;
diff --git a/server/src/test/java/org/opensearch/watcher/FileWatcherTests.java b/server/src/test/java/org/opensearch/watcher/FileWatcherTests.java
index 74c9cd91b72f0..2f5787ffff29f 100644
--- a/server/src/test/java/org/opensearch/watcher/FileWatcherTests.java
+++ b/server/src/test/java/org/opensearch/watcher/FileWatcherTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.watcher;
 
-import org.opensearch.core.internal.io.IOUtils;
 import org.apache.lucene.tests.util.LuceneTestCase;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.BufferedWriter;
diff --git a/server/src/test/resources/config/opensearch.yml b/server/src/test/resources/config/opensearch.yml
index b6ebc6bd10576..21f4f7b1b933a 100644
--- a/server/src/test/resources/config/opensearch.yml
+++ b/server/src/test/resources/config/opensearch.yml
@@ -1,3 +1,2 @@
 
 yaml.config.exists: true
-
diff --git a/server/src/test/resources/indices/analyze/conf_dir/hunspell/en_US_custom/settings.yml b/server/src/test/resources/indices/analyze/conf_dir/hunspell/en_US_custom/settings.yml
index 1a91653e56a1d..7e9eed5920f2e 100644
--- a/server/src/test/resources/indices/analyze/conf_dir/hunspell/en_US_custom/settings.yml
+++ b/server/src/test/resources/indices/analyze/conf_dir/hunspell/en_US_custom/settings.yml
@@ -1,2 +1,2 @@
 ignore_case: true
-strict_affix_parsing: true
\ No newline at end of file
+strict_affix_parsing: true
diff --git a/server/src/test/resources/indices/bwc/es-6.3.0/README.md b/server/src/test/resources/indices/bwc/es-6.3.0/README.md
new file mode 100644
index 0000000000000..a9f969475aaad
--- /dev/null
+++ b/server/src/test/resources/indices/bwc/es-6.3.0/README.md
@@ -0,0 +1,57 @@
+# README for _testIndex-es-6.3.0.zip_
+
+This zip file holds a Lucene index created using ElasticSearch 6.3.0.
+It was created by running the underlying commands against a single-node cluster,
+then compressing the contents of the underlying Lucene index directory i.e.
+the files under `<elasticsearch-root>/data/nodes/0/indices/<index-uuid>/0/index`.
+The index contains one document.
+
+## Commands
+
+```
+curl -X PUT -H 'Content-Type: application/json' 'localhost:9200/testindex?pretty' -d'
+{
+  "settings": {
+    "number_of_shards": 1,
+    "number_of_replicas": 0
+  },
+  "mappings": {
+    "testData": {
+      "properties": {
+        "id": { "type": "keyword" },
+        "isTestData": { "type": "boolean" },
+        "testNum": { "type": "short" },
+        "testRange": {"type": "integer_range" },
+        "testMessage": {
+          "type": "text",
+          "fields": {
+            "length": {
+              "type": "token_count",
+              "analyzer": "standard"
+            }
+          }
+        },
+        "testBlob": { "type": "binary", "index": false },
+        "testDate": { "type": "date" },
+        "testLocation": { "type": "geo_point"}
+      }
+    }
+  }
+}'
+
+curl -X POST "localhost:9200/testindex/testData/?pretty" -H 'Content-Type: application/json' -d'
+{
+  "id": "testData1",
+  "isTestData": true,
+  "testNum": 99,
+  "testRange": {
+    "gte": 0,
+    "lte": 100
+  },
+  "testMessage": "The OpenSearch Project",
+  "testBlob": "VGhlIE9wZW5TZWFyY2ggUHJvamVjdA==",
+  "testDate": "1970-01-02",
+  "testLocation": "48.553532,-113.022881"
+}
+'
+```
diff --git a/server/src/test/resources/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip b/server/src/test/resources/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip
new file mode 100644
index 0000000000000..db86a76153b25
Binary files /dev/null and b/server/src/test/resources/indices/bwc/es-6.3.0/testIndex-es-6.3.0.zip differ
diff --git a/server/src/test/resources/org/opensearch/action/admin/invalid.txt.keystore b/server/src/test/resources/org/opensearch/action/admin/invalid.txt.keystore
index 04613ffab7f36..a18f3707ac0d9 100644
--- a/server/src/test/resources/org/opensearch/action/admin/invalid.txt.keystore
+++ b/server/src/test/resources/org/opensearch/action/admin/invalid.txt.keystore
@@ -1,3 +1,2 @@
 admin admin
 dragon 12345
-
diff --git a/server/src/test/resources/org/opensearch/action/fieldstats/fieldstats-index-constraints-request.json b/server/src/test/resources/org/opensearch/action/fieldstats/fieldstats-index-constraints-request.json
index eb8ca972dcd52..8fbf7684b6819 100644
--- a/server/src/test/resources/org/opensearch/action/fieldstats/fieldstats-index-constraints-request.json
+++ b/server/src/test/resources/org/opensearch/action/fieldstats/fieldstats-index-constraints-request.json
@@ -40,4 +40,4 @@
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis.json b/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis.json
index 33c09fe8dbd9f..4a4fc7d2c81b1 100644
--- a/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis.json
+++ b/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis.json
@@ -17,7 +17,7 @@
                     "output_unigrams" : false,
                     "filler_token" : "FILLER"
                 }
-            }            
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis2.json b/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis2.json
index a81ea538f19fe..5927549c111fd 100644
--- a/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis2.json
+++ b/server/src/test/resources/org/opensearch/index/analysis/shingle_analysis2.json
@@ -9,7 +9,7 @@
                     "output_unigrams" : false,
                     "filler_token" : "FILLER"
                 }
-            }            
+            }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/analysis/stop.json b/server/src/test/resources/org/opensearch/index/analysis/stop.json
index 717c9fdee5b08..c59b0fb5056d0 100644
--- a/server/src/test/resources/org/opensearch/index/analysis/stop.json
+++ b/server/src/test/resources/org/opensearch/index/analysis/stop.json
@@ -15,4 +15,4 @@
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/genericstore/test-data.json b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/genericstore/test-data.json
index b7439dcb9fe6f..14ebf16d92f36 100644
--- a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/genericstore/test-data.json
+++ b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/genericstore/test-data.json
@@ -1,4 +1,4 @@
 {
     "name":"some name",
     "age":1
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-data.json b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-data.json
index 2e6ec997c4612..765a850b0b663 100644
--- a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-data.json
+++ b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/pathmatch/test-data.json
@@ -11,4 +11,4 @@
             "prop1":"prop1_value"
         }
     }
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/simple/test-data.json b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/simple/test-data.json
index 1ed3c50b98d59..8509d846c13bb 100644
--- a/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/simple/test-data.json
+++ b/server/src/test/resources/org/opensearch/index/mapper/dynamictemplate/simple/test-data.json
@@ -3,4 +3,4 @@
     "age":1,
     "multi1":"multi 1",
     "multi2":"multi 2"
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/mapper/multifield/merge/test-data.json b/server/src/test/resources/org/opensearch/index/mapper/multifield/merge/test-data.json
index c539fcc885d3c..ec6b1b95ed888 100644
--- a/server/src/test/resources/org/opensearch/index/mapper/multifield/merge/test-data.json
+++ b/server/src/test/resources/org/opensearch/index/mapper/multifield/merge/test-data.json
@@ -1,4 +1,4 @@
 {
     _id:1,
     name:"some name"
-}
\ No newline at end of file
+}
diff --git a/server/src/test/resources/org/opensearch/index/mapper/multifield/test-data.json b/server/src/test/resources/org/opensearch/index/mapper/multifield/test-data.json
index 2e8ab256df92a..fd7ecad71b894 100644
--- a/server/src/test/resources/org/opensearch/index/mapper/multifield/test-data.json
+++ b/server/src/test/resources/org/opensearch/index/mapper/multifield/test-data.json
@@ -4,4 +4,4 @@
     "object1":{
         "multi1":"2010-01-01"
     }
-}
\ No newline at end of file
+}
diff --git a/settings.gradle b/settings.gradle
index cb8167ee02efe..c04b5997d49b1 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -10,7 +10,14 @@
  */
 
 plugins {
-  id "com.gradle.enterprise" version "3.9"
+  id "com.gradle.enterprise" version "3.14.1"
+}
+
+buildCache {
+  local {
+    enabled = true
+    removeUnusedEntriesAfterDays = 14
+  }
 }
 
 rootProject.name = "OpenSearch"
@@ -40,17 +47,26 @@ List projects = [
   'distribution:archives:freebsd-tar',
   'distribution:archives:no-jdk-freebsd-tar',
   'distribution:archives:linux-arm64-tar',
+  'distribution:archives:no-jdk-linux-arm64-tar',
+  'distribution:archives:linux-s390x-tar',
+  'distribution:archives:linux-ppc64le-tar',
+  'distribution:archives:no-jdk-linux-ppc64le-tar',
   'distribution:archives:linux-tar',
   'distribution:archives:no-jdk-linux-tar',
+  'distribution:archives:jre-linux-tar',
   'distribution:docker',
   'distribution:docker:docker-arm64-build-context',
   'distribution:docker:docker-arm64-export',
+  'distribution:docker:docker-s390x-export',
+  'distribution:docker:docker-ppc64le-export',
   'distribution:docker:docker-build-context',
   'distribution:docker:docker-export',
   'distribution:packages:arm64-deb',
+  'distribution:packages:no-jdk-arm64-deb',
   'distribution:packages:deb',
   'distribution:packages:no-jdk-deb',
   'distribution:packages:arm64-rpm',
+  'distribution:packages:no-jdk-arm64-rpm',
   'distribution:packages:rpm',
   'distribution:packages:no-jdk-rpm',
   'distribution:bwc:bugfix',
@@ -72,7 +88,8 @@ List projects = [
   'test:fixtures:minio-fixture',
   'test:fixtures:old-elasticsearch',
   'test:fixtures:s3-fixture',
-  'test:logger-usage'
+  'test:logger-usage',
+  'test:telemetry'
 ]
 
 /**
@@ -136,4 +153,3 @@ if (extraProjects.exists()) {
     addSubProjects('', extraProjectDir)
   }
 }
-
diff --git a/test/external-modules/delayed-aggs/src/internalClusterTest/java/org/opensearch/search/aggregations/DelayedShardAggregationIT.java b/test/external-modules/delayed-aggs/src/internalClusterTest/java/org/opensearch/search/aggregations/DelayedShardAggregationIT.java
index e850ae9dcc859..90f4f1ba2ceb2 100644
--- a/test/external-modules/delayed-aggs/src/internalClusterTest/java/org/opensearch/search/aggregations/DelayedShardAggregationIT.java
+++ b/test/external-modules/delayed-aggs/src/internalClusterTest/java/org/opensearch/search/aggregations/DelayedShardAggregationIT.java
@@ -31,25 +31,43 @@
 
 package org.opensearch.search.aggregations;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilter;
 import org.opensearch.search.aggregations.metrics.InternalMax;
 import org.opensearch.search.aggregations.metrics.MaxAggregationBuilder;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 
-public class DelayedShardAggregationIT extends OpenSearchIntegTestCase {
+public class DelayedShardAggregationIT extends ParameterizedOpenSearchIntegTestCase {
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
diff --git a/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationBuilder.java b/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationBuilder.java
index 4c1dd33d1fdd9..006632ca93925 100644
--- a/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationBuilder.java
+++ b/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationBuilder.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.ConstructingObjectParser;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.ConstructingObjectParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.search.aggregations.bucket.filter.FilterAggregationBuilder;
@@ -137,6 +137,11 @@ protected Aggregator createInternal(
                 } while (searchContext.getRelativeTimeInMillis() - start < delay.getMillis());
                 return factory.create(searchContext, parent, cardinality);
             }
+
+            @Override
+            protected boolean supportsConcurrentSegmentSearch() {
+                return true;
+            }
         };
     }
 
diff --git a/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationPlugin.java b/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationPlugin.java
index e896a55c998a5..e2ba59a59a6e5 100644
--- a/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationPlugin.java
+++ b/test/external-modules/delayed-aggs/src/main/java/org/opensearch/search/aggregations/DelayedShardAggregationPlugin.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.search.aggregations;
 
-import java.util.List;
-
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.search.aggregations.bucket.filter.InternalFilter;
 
+import java.util.List;
+
 import static java.util.Collections.singletonList;
 
 /**
diff --git a/test/fixtures/azure-fixture/src/main/java/fixture/azure/AzureHttpHandler.java b/test/fixtures/azure-fixture/src/main/java/fixture/azure/AzureHttpHandler.java
index f12a4579a2d0c..f3589dcfce3e5 100644
--- a/test/fixtures/azure-fixture/src/main/java/fixture/azure/AzureHttpHandler.java
+++ b/test/fixtures/azure-fixture/src/main/java/fixture/azure/AzureHttpHandler.java
@@ -35,11 +35,11 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 
 import java.io.ByteArrayOutputStream;
@@ -150,12 +150,16 @@ public void handle(final HttpExchange exchange) throws IOException {
                 }
 
                 final int start = Integer.parseInt(matcher.group(1));
-                final int length = Integer.parseInt(matcher.group(2)) - start + 1;
+                final int end = Integer.parseInt(matcher.group(2));
+                final int length = Math.min(end - start + 1, blob.length());
 
                 exchange.getResponseHeaders().add("Content-Type", "application/octet-stream");
                 exchange.getResponseHeaders().add("Content-Length", String.valueOf(length));
                 exchange.getResponseHeaders().add("x-ms-blob-type", "blockblob");
                 exchange.getResponseHeaders().add("x-ms-request-server-encrypted", "false");
+                exchange.getResponseHeaders()
+                    .add("Content-Range", "bytes " + start + "-" + Math.min(end, length) + "/" + blob.length());
+
                 exchange.sendResponseHeaders(RestStatus.OK.getStatus(), length);
                 exchange.getResponseBody().write(blob.toBytesRef().bytes, start, length);
 
diff --git a/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/FakeOAuth2HttpHandler.java b/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/FakeOAuth2HttpHandler.java
index 611ec7b5198d9..f4ef1be4a9a3d 100644
--- a/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/FakeOAuth2HttpHandler.java
+++ b/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/FakeOAuth2HttpHandler.java
@@ -34,7 +34,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 
diff --git a/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/GoogleCloudStorageHttpHandler.java b/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/GoogleCloudStorageHttpHandler.java
index af3faa46e2169..358d573629e0a 100644
--- a/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/GoogleCloudStorageHttpHandler.java
+++ b/test/fixtures/gcs-fixture/src/main/java/fixture/gcs/GoogleCloudStorageHttpHandler.java
@@ -36,16 +36,16 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 
 import java.io.BufferedReader;
diff --git a/test/fixtures/hdfs-fixture/build.gradle b/test/fixtures/hdfs-fixture/build.gradle
index d1040acd03aa7..c4ca7346fb6c2 100644
--- a/test/fixtures/hdfs-fixture/build.gradle
+++ b/test/fixtures/hdfs-fixture/build.gradle
@@ -32,15 +32,44 @@ apply plugin: 'opensearch.java'
 
 group = 'hdfs'
 
+versions << [
+  'jetty': '9.4.51.v20230217'
+]
+
 dependencies {
-  api "org.apache.hadoop:hadoop-minicluster:3.3.1"
-  api "org.apache.commons:commons-compress:1.21"
+  api("org.apache.hadoop:hadoop-minicluster:3.3.6") {
+    exclude module: 'websocket-client'
+    exclude module: 'jettison'
+    exclude module: 'netty'
+    exclude module: 'guava'
+    exclude group: 'org.codehaus.jackson'
+    exclude group: "org.bouncycastle"
+    exclude group: "com.squareup.okhttp3"
+    exclude group: "org.xerial.snappy"
+    exclude module: "json-io"
+  }
+  api "org.codehaus.jettison:jettison:${versions.jettison}"
+  api "org.apache.commons:commons-compress:${versions.commonscompress}"
   api "commons-codec:commons-codec:${versions.commonscodec}"
   api "org.apache.logging.log4j:log4j-core:${versions.log4j}"
   api "io.netty:netty-all:${versions.netty}"
   api 'com.google.code.gson:gson:2.9.0'
-  api "org.bouncycastle:bcpkix-jdk15on:${versions.bouncycastle}"
   api "com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:${versions.jackson}"
-  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson}"
-  api 'net.minidev:json-smart:2.4.8'
+  api "com.fasterxml.jackson.core:jackson-databind:${versions.jackson_databind}"
+  api "com.fasterxml.woodstox:woodstox-core:${versions.woodstox}"
+  api 'net.minidev:json-smart:2.4.11'
+  api "org.mockito:mockito-core:${versions.mockito}"
+  api "com.google.protobuf:protobuf-java:3.22.2"
+  api "org.jetbrains.kotlin:kotlin-stdlib:${versions.kotlin}"
+  api "org.eclipse.jetty:jetty-server:${versions.jetty}"
+  api "org.eclipse.jetty.websocket:javax-websocket-server-impl:${versions.jetty}"
+  api 'org.apache.zookeeper:zookeeper:3.9.0'
+  api "org.apache.commons:commons-text:1.10.0"
+  api "commons-net:commons-net:3.9.0"
+  runtimeOnly "com.google.guava:guava:${versions.guava}"
+  runtimeOnly("com.squareup.okhttp3:okhttp:4.11.0") {
+    exclude group: "com.squareup.okio"
+  }
+  runtimeOnly "com.squareup.okio:okio:3.5.0"
+  runtimeOnly "org.xerial.snappy:snappy-java:1.1.10.5"
 }
diff --git a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/addprinc.sh b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/addprinc.sh
index a58df6d47f36f..2e3bf66d1403b 100755
--- a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/addprinc.sh
+++ b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/addprinc.sh
@@ -17,7 +17,7 @@
 # specific language governing permissions and limitations
 # under the License.
 
-set -e
+set -e -o pipefail
 
 krb5kdc
 kadmind
@@ -72,4 +72,4 @@ echo "Copying conf to local"
 # make the configuration available externally
 cp -v $LOCALSTATEDIR/krb5.conf $BUILD_DIR/krb5.conf.template
 # We are running as root in the container, allow non root users running the container to be able to clean these up
-chmod -R 777 $BUILD_DIR
\ No newline at end of file
+chmod -R 777 $BUILD_DIR
diff --git a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/hdfs.sh b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/hdfs.sh
index 413c1ee29d0d9..81bc99a058344 100644
--- a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/hdfs.sh
+++ b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/hdfs.sh
@@ -10,7 +10,7 @@
 # GitHub history for details.
 #
 
-set -e
+set -e -o pipefail
 
 addprinc.sh "opensearch"
 #TODO(OpenSearch): fix username
diff --git a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/installkdc.sh b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/installkdc.sh
index aec2d46073c83..111e8dcc5ea70 100755
--- a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/installkdc.sh
+++ b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/installkdc.sh
@@ -29,7 +29,7 @@
 # GitHub history for details.
 #
 
-set -e
+set -e -o pipefail
 
 # KDC installation steps and considerations based on https://web.mit.edu/kerberos/krb5-latest/doc/admin/install_kdc.html
 # and helpful input from https://help.ubuntu.com/community/Kerberos
diff --git a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/krb5.conf.template b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/krb5.conf.template
index ba0832b2b7d99..207fe939fb7a5 100644
--- a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/krb5.conf.template
+++ b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/krb5.conf.template
@@ -59,4 +59,3 @@
     .${BUILD_ZONE} = ${REALM_NAME}
     ${OPENSEARCH_ZONE} = ${REALM_NAME}
     .${OPENSEARCH_ZONE} = ${REALM_NAME}
-
diff --git a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/peppa.sh b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/peppa.sh
index f70ad575d6582..422739d9df90d 100644
--- a/test/fixtures/krb5kdc-fixture/src/main/resources/provision/peppa.sh
+++ b/test/fixtures/krb5kdc-fixture/src/main/resources/provision/peppa.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-set -e
+set -e -o pipefail
 
 addprinc.sh opensearch
 addprinc.sh HTTP/localhost
diff --git a/test/fixtures/minio-fixture/Dockerfile b/test/fixtures/minio-fixture/Dockerfile
index 54bb562c790c1..81655aa545afd 100644
--- a/test/fixtures/minio-fixture/Dockerfile
+++ b/test/fixtures/minio-fixture/Dockerfile
@@ -1,9 +1,9 @@
-FROM minio/minio:RELEASE.2019-01-23T23-18-58Z
+FROM minio/minio:RELEASE.2022-11-17T23-20-09Z
 
 ARG bucket
 ARG accessKey
 ARG secretKey
 
 RUN mkdir -p /minio/data/${bucket}
-ENV MINIO_ACCESS_KEY=${accessKey}
-ENV MINIO_SECRET_KEY=${secretKey}
+ENV MINIO_ROOT_USER=${accessKey}
+ENV MINIO_ROOT_PASSWORD=${secretKey}
diff --git a/test/fixtures/minio-fixture/build.gradle b/test/fixtures/minio-fixture/build.gradle
index ba5e0a7d2d814..61f417690b210 100644
--- a/test/fixtures/minio-fixture/build.gradle
+++ b/test/fixtures/minio-fixture/build.gradle
@@ -30,4 +30,3 @@
 apply plugin: 'opensearch.test.fixtures'
 
 description = 'Fixture for MinIO Storage service'
-
diff --git a/test/fixtures/minio-fixture/docker-compose.yml b/test/fixtures/minio-fixture/docker-compose.yml
index 7b66f04152b47..e4d2faab9a657 100644
--- a/test/fixtures/minio-fixture/docker-compose.yml
+++ b/test/fixtures/minio-fixture/docker-compose.yml
@@ -8,9 +8,21 @@ services:
         accessKey: "access_key"
         secretKey: "secret_key"
       dockerfile: Dockerfile
+    ulimits:
+      nofile:
+        hard: 4096
+        soft: 4096
     ports:
       - "9000"
-    command: ["server", "/minio/data"]
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+    volumes:
+      - type: tmpfs
+        target: /minio/data
+    command: ["server", "--console-address", ":9001", "/minio/data"]
   minio-fixture-other:
     build:
       context: .
@@ -19,17 +31,41 @@ services:
         accessKey: "access_key"
         secretKey: "secret_key"
       dockerfile: Dockerfile
+    ulimits:
+      nofile:
+        hard: 4096
+        soft: 4096
     ports:
       - "9000"
-    command: ["server", "/minio/data"]
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+    volumes:
+      - type: tmpfs
+        target: /minio/data
+    command: ["server", "--console-address", ":9001", "/minio/data"]
   minio-fixture-for-snapshot-tool:
-      build:
-        context: .
-        args:
-          bucket: "bucket"
-          accessKey: "sn_tool_access_key"
-          secretKey: "sn_tool_secret_key"
-        dockerfile: Dockerfile
-      ports:
-        - "9000"
-      command: ["server", "/minio/data"]
+    build:
+      context: .
+      args:
+        bucket: "bucket"
+        accessKey: "sn_tool_access_key"
+        secretKey: "sn_tool_secret_key"
+      dockerfile: Dockerfile
+    ulimits:
+      nofile:
+        hard: 4096
+        soft: 4096
+    ports:
+      - "9000"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+    volumes:
+      - type: tmpfs
+        target: /minio/data
+    command: ["server", "--console-address", ":9001", "/minio/data"]
diff --git a/test/fixtures/s3-fixture/Dockerfile.eks b/test/fixtures/s3-fixture/Dockerfile.eks
new file mode 100644
index 0000000000000..d03960472a6a8
--- /dev/null
+++ b/test/fixtures/s3-fixture/Dockerfile.eks
@@ -0,0 +1,25 @@
+FROM ubuntu:18.04
+
+RUN apt-get update -qqy
+RUN apt-get install -qqy openjdk-11-jre-headless
+
+ARG fixtureClass
+ARG port
+ARG bucket
+ARG basePath
+ARG accessKey
+ARG roleArn
+ARG roleSessionName
+
+ENV S3_FIXTURE_CLASS=${fixtureClass}
+ENV S3_FIXTURE_PORT=${port}
+ENV S3_FIXTURE_BUCKET=${bucket}
+ENV S3_FIXTURE_BASE_PATH=${basePath}
+ENV S3_FIXTURE_ACCESS_KEY=${accessKey}
+ENV S3_FIXTURE_ROLE_ARN=${roleArn}
+ENV S3_FIXTURE_ROLE_SESSION_NAME=${roleSessionName}
+
+ENTRYPOINT exec java -classpath "/fixture/shared/*" \
+    $S3_FIXTURE_CLASS 0.0.0.0 "$S3_FIXTURE_PORT" "$S3_FIXTURE_BUCKET" "$S3_FIXTURE_BASE_PATH" "$S3_FIXTURE_ACCESS_KEY" "$S3_FIXTURE_ROLE_ARN" "$S3_FIXTURE_ROLE_SESSION_NAME"
+
+EXPOSE $port
diff --git a/test/fixtures/s3-fixture/docker-compose.yml b/test/fixtures/s3-fixture/docker-compose.yml
index 22d101f41c318..d2b44f13c9530 100644
--- a/test/fixtures/s3-fixture/docker-compose.yml
+++ b/test/fixtures/s3-fixture/docker-compose.yml
@@ -92,3 +92,20 @@ services:
           - ./testfixtures_shared/shared:/fixture/shared
       ports:
           - "80"
+
+  s3-fixture-with-eks:
+      build:
+          context: .
+          args:
+              fixtureClass: fixture.s3.S3HttpFixtureWithEKS
+              port: 80
+              bucket: "eks_bucket"
+              basePath: "eks_base_path"
+              accessKey: "eks_access_key"
+              roleArn: "eks_role_arn"
+              roleSessionName: "eks_role_session_name"
+          dockerfile: Dockerfile.eks
+      volumes:
+          - ./testfixtures_shared/shared:/fixture/shared
+      ports:
+          - "80"
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixture.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixture.java
index 88bd6a63c270d..d845b0b2a1b19 100644
--- a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixture.java
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixture.java
@@ -34,7 +34,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.io.IOException;
 import java.net.InetAddress;
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEC2.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEC2.java
index 882d24145d67c..9e02f9ee86744 100644
--- a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEC2.java
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEC2.java
@@ -32,7 +32,7 @@
 package fixture.s3;
 
 import com.sun.net.httpserver.HttpHandler;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.nio.charset.StandardCharsets;
 import java.time.ZonedDateTime;
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithECS.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithECS.java
index 7e261717f8201..ac5e3fdfdf85c 100644
--- a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithECS.java
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithECS.java
@@ -32,7 +32,7 @@
 package fixture.s3;
 
 import com.sun.net.httpserver.HttpHandler;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.nio.charset.StandardCharsets;
 import java.util.Objects;
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEKS.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEKS.java
new file mode 100644
index 0000000000000..8a28656760bcc
--- /dev/null
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithEKS.java
@@ -0,0 +1,103 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package fixture.s3;
+
+import com.sun.net.httpserver.HttpHandler;
+import org.opensearch.core.rest.RestStatus;
+
+import java.nio.charset.StandardCharsets;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Objects;
+
+public class S3HttpFixtureWithEKS extends S3HttpFixture {
+
+    private S3HttpFixtureWithEKS(final String[] args) throws Exception {
+        super(args);
+    }
+
+    @Override
+    protected HttpHandler createHandler(final String[] args) {
+        final String accessKey = Objects.requireNonNull(args[4]);
+        final String eksRoleArn = Objects.requireNonNull(args[5]);
+        final HttpHandler delegate = super.createHandler(args);
+
+        return exchange -> {
+            // https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html
+            if ("POST".equals(exchange.getRequestMethod()) && exchange.getRequestURI().getPath().startsWith("/eks_credentials_endpoint")) {
+                final byte[] response = buildCredentialResponse(eksRoleArn, accessKey).getBytes(StandardCharsets.UTF_8);
+                exchange.getResponseHeaders().add("Content-Type", "application/xml");
+                exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
+                exchange.getResponseBody().write(response);
+                exchange.close();
+                return;
+            }
+
+            delegate.handle(exchange);
+        };
+    }
+
+    protected String buildCredentialResponse(final String roleArn, final String accessKey) {
+        // See please: https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html
+        return "<AssumeRoleWithWebIdentityResponse xmlns=\"https://sts.amazonaws.com/doc/2011-06-15/\">\n"
+                + "  <AssumeRoleWithWebIdentityResult>\n"
+                + "    <SubjectFromWebIdentityToken>amzn1.account.AF6RHO7KZU5XRVQJGXK6HB56KR2A</SubjectFromWebIdentityToken>\n"
+                + "    <Audience>client.5498841531868486423.1548@apps.example.com</Audience>\n"
+                + "    <AssumedRoleUser>\n"
+                + "      <Arn>" + roleArn + "</Arn>\n"
+                + "      <AssumedRoleId>AROACLKWSDQRAOEXAMPLE:s3</AssumedRoleId>\n"
+                + "    </AssumedRoleUser>\n"
+                + "    <Credentials>\n"
+                + "      <SessionToken>AQoDYXdzEE0a8ANXXXXXXXXNO1ewxE5TijQyp+IEXAMPLE</SessionToken>\n"
+                + "      <SecretAccessKey>wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY</SecretAccessKey>\n"
+                + "      <Expiration>" + LocalDateTime.now().plusMonths(1).atZone(ZoneId.of("UTC")).format(DateTimeFormatter.ISO_OFFSET_DATE_TIME) + "</Expiration>\n"
+                + "      <AccessKeyId>" + accessKey + "</AccessKeyId>\n"
+                + "    </Credentials>\n"
+                + "    <SourceIdentity>SourceIdentityValue</SourceIdentity>\n"
+                + "    <Provider>www.amazon.com</Provider>\n"
+                + "  </AssumeRoleWithWebIdentityResult>\n"
+                + "  <ResponseMetadata>\n"
+                + "    <RequestId>ad4156e9-bce1-11e2-82e6-6b6efEXAMPLE</RequestId>\n"
+                + "  </ResponseMetadata>\n"
+                + "</AssumeRoleWithWebIdentityResponse>";
+    }
+
+    public static void main(final String[] args) throws Exception {
+        if (args == null || args.length < 6) {
+            throw new IllegalArgumentException("S3HttpFixtureWithEKS expects 6 arguments " +
+                "[address, port, bucket, base path, role arn, role session name]");
+        }
+        final S3HttpFixtureWithEKS fixture = new S3HttpFixtureWithEKS(args);
+        fixture.start();
+    }
+}
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithSessionToken.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithSessionToken.java
index b9a4fe36b687b..e5da27c639ca6 100644
--- a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithSessionToken.java
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpFixtureWithSessionToken.java
@@ -32,7 +32,7 @@
 package fixture.s3;
 
 import com.sun.net.httpserver.HttpHandler;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 
 import java.util.Objects;
 
diff --git a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpHandler.java b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpHandler.java
index e8b01948ae51b..3863cda9b8c96 100644
--- a/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpHandler.java
+++ b/test/fixtures/s3-fixture/src/main/java/fixture/s3/S3HttpHandler.java
@@ -37,13 +37,13 @@
 import org.opensearch.common.Nullable;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.hash.MessageDigests;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.regex.Regex;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.RestUtils;
 
 import java.io.BufferedInputStream;
@@ -97,14 +97,14 @@ public void handle(final HttpExchange exchange) throws IOException {
             assert read == -1 : "Request body should have been empty but saw [" + read + "]";
         }
         try {
-            if (Regex.simpleMatch("HEAD /" + path + "/*", request)) {
+            if (Regex.simpleMatch("HEAD /" + path + "*", request)) {
                 final BytesReference blob = blobs.get(exchange.getRequestURI().getPath());
                 if (blob == null) {
                     exchange.sendResponseHeaders(RestStatus.NOT_FOUND.getStatus(), -1);
                 } else {
                     exchange.sendResponseHeaders(RestStatus.OK.getStatus(), -1);
                 }
-            } else if (Regex.simpleMatch("POST /" + path + "/*?uploads", request)) {
+            } else if (Regex.simpleMatch("POST /" + path + "*?uploads", request)) {
                 final String uploadId = UUIDs.randomBase64UUID();
                 byte[] response = ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
                     "<InitiateMultipartUploadResult>\n" +
@@ -117,7 +117,7 @@ public void handle(final HttpExchange exchange) throws IOException {
                 exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
                 exchange.getResponseBody().write(response);
 
-            } else if (Regex.simpleMatch("PUT /" + path + "/*?uploadId=*&partNumber=*", request)) {
+            } else if (Regex.simpleMatch("PUT /" + path + "*?partNumber=*&uploadId=*", request)) {
                 final Map<String, String> params = new HashMap<>();
                 RestUtils.decodeQueryString(exchange.getRequestURI().getQuery(), 0, params);
 
@@ -132,7 +132,7 @@ public void handle(final HttpExchange exchange) throws IOException {
                     exchange.sendResponseHeaders(RestStatus.NOT_FOUND.getStatus(), -1);
                 }
 
-            } else if (Regex.simpleMatch("POST /" + path + "/*?uploadId=*", request)) {
+            } else if (Regex.simpleMatch("POST /" + path + "*?uploadId=*", request)) {
                 Streams.readFully(exchange.getRequestBody());
                 final Map<String, String> params = new HashMap<>();
                 RestUtils.decodeQueryString(exchange.getRequestURI().getQuery(), 0, params);
@@ -164,18 +164,15 @@ public void handle(final HttpExchange exchange) throws IOException {
                 exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
                 exchange.getResponseBody().write(response);
 
-            } else if (Regex.simpleMatch("PUT /" + path + "/*", request)) {
+            } else if (Regex.simpleMatch("PUT /" + path + "*", request)) {
                 final Tuple<String, BytesReference> blob = parseRequestBody(exchange);
                 blobs.put(exchange.getRequestURI().toString(), blob.v2());
                 exchange.getResponseHeaders().add("ETag", blob.v1());
                 exchange.sendResponseHeaders(RestStatus.OK.getStatus(), -1);
 
-            } else if (Regex.simpleMatch("GET /" + bucket + "/?prefix=*", request)) {
+            } else if (Regex.simpleMatch("GET /" + bucket + "?list-type=*", request)) {
                 final Map<String, String> params = new HashMap<>();
                 RestUtils.decodeQueryString(exchange.getRequestURI().getQuery(), 0, params);
-                if (params.get("list-type") != null) {
-                    throw new AssertionError("Test must be adapted for GET Bucket (List Objects) Version 2");
-                }
 
                 final StringBuilder list = new StringBuilder();
                 list.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
@@ -208,9 +205,11 @@ public void handle(final HttpExchange exchange) throws IOException {
                     list.append("</Contents>");
                 }
                 if (commonPrefixes.isEmpty() == false) {
-                    list.append("<CommonPrefixes>");
-                    commonPrefixes.forEach(commonPrefix -> list.append("<Prefix>").append(commonPrefix).append("</Prefix>"));
-                    list.append("</CommonPrefixes>");
+                    commonPrefixes.forEach(commonPrefix -> {
+                        list.append("<CommonPrefixes>");
+                        list.append("<Prefix>").append(commonPrefix).append("</Prefix>");
+                        list.append("</CommonPrefixes>");
+                    });
 
                 }
                 list.append("</ListBucketResult>");
@@ -220,7 +219,7 @@ public void handle(final HttpExchange exchange) throws IOException {
                 exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
                 exchange.getResponseBody().write(response);
 
-            } else if (Regex.simpleMatch("GET /" + path + "/*", request)) {
+            } else if (Regex.simpleMatch("GET /" + path + "*", request)) {
                 final BytesReference blob = blobs.get(exchange.getRequestURI().toString());
                 if (blob != null) {
                     final String range = exchange.getRequestHeaders().getFirst("Range");
@@ -248,7 +247,7 @@ public void handle(final HttpExchange exchange) throws IOException {
                     exchange.sendResponseHeaders(RestStatus.NOT_FOUND.getStatus(), -1);
                 }
 
-            } else if (Regex.simpleMatch("DELETE /" + path + "/*", request)) {
+            } else if (Regex.simpleMatch("DELETE /" + path + "*", request)) {
                 int deletions = 0;
                 for (Iterator<Map.Entry<String, BytesReference>> iterator = blobs.entrySet().iterator(); iterator.hasNext(); ) {
                     Map.Entry<String, BytesReference> blob = iterator.next();
@@ -259,7 +258,7 @@ public void handle(final HttpExchange exchange) throws IOException {
                 }
                 exchange.sendResponseHeaders((deletions > 0 ? RestStatus.OK : RestStatus.NO_CONTENT).getStatus(), -1);
 
-            } else if (Regex.simpleMatch("POST /" + bucket + "/?delete", request)) {
+            } else if (Regex.simpleMatch("POST /" + bucket + "?delete", request)) {
                 final String requestBody = Streams.copyToString(new InputStreamReader(exchange.getRequestBody(), UTF_8));
 
                 final StringBuilder deletes = new StringBuilder();
diff --git a/test/framework/build.gradle b/test/framework/build.gradle
index 42197bf5e2980..c65bf51c6af36 100644
--- a/test/framework/build.gradle
+++ b/test/framework/build.gradle
@@ -27,7 +27,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import org.opensearch.gradle.info.BuildParams;
+import org.opensearch.gradle.info.BuildParams
 
 apply plugin: 'opensearch.build'
 apply plugin: 'opensearch.publish'
@@ -38,6 +38,7 @@ dependencies {
   api project(':libs:opensearch-nio')
   api project(":server")
   api project(":libs:opensearch-cli")
+  api project(":test:telemetry")
   api "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
   api "junit:junit:${versions.junit}"
   api "org.hamcrest:hamcrest:${versions.hamcrest}"
@@ -48,11 +49,14 @@ dependencies {
   api "org.mockito:mockito-core:${versions.mockito}"
   api "net.bytebuddy:byte-buddy:${versions.bytebuddy}"
   api "org.objenesis:objenesis:${versions.objenesis}"
+
+  annotationProcessor "org.apache.logging.log4j:log4j-core:${versions.log4j}"
 }
 
 compileJava.options.compilerArgs -= '-Xlint:cast'
 compileJava.options.compilerArgs -= '-Xlint:rawtypes'
 compileJava.options.compilerArgs -= '-Xlint:unchecked'
+compileJava.options.compilerArgs += ['-processor', 'org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor']
 compileTestJava.options.compilerArgs -= '-Xlint:rawtypes'
 
 // the main files are actually test files, so use the appropriate forbidden api sigs
@@ -71,7 +75,6 @@ thirdPartyAudit.ignoreMissingClasses(
   'org.apache.avalon.framework.logger.Logger',
   'org.apache.log.Hierarchy',
   'org.apache.log.Logger',
-  'org.apache.log4j.Category',
   'org.apache.log4j.Level',
   'org.apache.log4j.Logger',
   'org.apache.log4j.Priority',
@@ -89,6 +92,10 @@ test {
   systemProperty 'tests.gradle_index_compat_versions', BuildParams.bwcVersions.indexCompatible.join(',')
   systemProperty 'tests.gradle_wire_compat_versions', BuildParams.bwcVersions.wireCompatible.join(',')
   systemProperty 'tests.gradle_unreleased_versions', BuildParams.bwcVersions.unreleased.join(',')
+
+  if (BuildParams.runtimeJavaVersion >= JavaVersion.VERSION_18) {
+    jvmArgs += ["-Djava.security.manager=allow"]
+  }
 }
 
 tasks.register("integTest", Test) {
diff --git a/test/framework/src/main/java/org/opensearch/action/support/ActionTestUtils.java b/test/framework/src/main/java/org/opensearch/action/support/ActionTestUtils.java
index 1403bf71a7f92..00fd5a5bcf815 100644
--- a/test/framework/src/main/java/org/opensearch/action/support/ActionTestUtils.java
+++ b/test/framework/src/main/java/org/opensearch/action/support/ActionTestUtils.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.action.support;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.common.CheckedConsumer;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.tasks.Task;
 
 import static org.opensearch.action.support.PlainActionFuture.newFuture;
diff --git a/test/framework/src/main/java/org/opensearch/action/support/replication/ClusterStateCreationUtils.java b/test/framework/src/main/java/org/opensearch/action/support/replication/ClusterStateCreationUtils.java
index 64b82f9fd1b92..f20c7edbed33e 100644
--- a/test/framework/src/main/java/org/opensearch/action/support/replication/ClusterStateCreationUtils.java
+++ b/test/framework/src/main/java/org/opensearch/action/support/replication/ClusterStateCreationUtils.java
@@ -50,7 +50,7 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
@@ -97,7 +97,7 @@ public static ClusterState state(
                 numberOfNodes++;
             }
         }
-        numberOfNodes = Math.max(2, numberOfNodes); // we need a non-local master to test shard failures
+        numberOfNodes = Math.max(2, numberOfNodes); // we need a non-local cluster-manager to test shard failures
         final ShardId shardId = new ShardId(index, "_na_", 0);
         DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
         Set<String> unassignedNodes = new HashSet<>();
@@ -107,7 +107,7 @@ public static ClusterState state(
             unassignedNodes.add(node.getId());
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(1).getId()); // we need a non-local master to test shard failures
+        discoBuilder.clusterManagerNodeId(newNode(1).getId()); // we need a non-local cluster-manager to test shard failures
         final int primaryTerm = 1 + randomInt(200);
         IndexMetadata indexMetadata = IndexMetadata.builder(index)
             .settings(
@@ -198,7 +198,7 @@ public static ClusterState state(String index, final int numberOfNodes, final in
             nodes.add(node.getId());
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(randomFrom(nodes));
+        discoBuilder.clusterManagerNodeId(randomFrom(nodes));
         IndexMetadata indexMetadata = IndexMetadata.builder(index)
             .settings(
                 Settings.builder()
@@ -240,7 +240,7 @@ public static ClusterState state(final int numberOfNodes, final String[] indices
             nodes.add(node.getId());
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(0).getId());
+        discoBuilder.clusterManagerNodeId(newNode(0).getId());
         Metadata.Builder metadata = Metadata.builder();
         RoutingTable.Builder routingTable = RoutingTable.builder();
         List<String> nodesList = new ArrayList<>(nodes);
@@ -284,14 +284,14 @@ public static ClusterState state(final int numberOfNodes, final String[] indices
      */
     public static ClusterState stateWithAssignedPrimariesAndOneReplica(String index, int numberOfShards) {
 
-        int numberOfNodes = 2; // we need a non-local master to test shard failures
+        int numberOfNodes = 2; // we need a non-local cluster-manager to test shard failures
         DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
         for (int i = 0; i < numberOfNodes + 1; i++) {
             final DiscoveryNode node = newNode(i);
             discoBuilder = discoBuilder.add(node);
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(1).getId()); // we need a non-local master to test shard failures
+        discoBuilder.clusterManagerNodeId(newNode(1).getId()); // we need a non-local cluster-manager to test shard failures
         IndexMetadata indexMetadata = IndexMetadata.builder(index)
             .settings(
                 Settings.builder()
@@ -332,7 +332,7 @@ public static ClusterState stateWithAssignedPrimariesAndReplicas(String[] indice
             discoBuilder = discoBuilder.add(node);
         }
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(numberOfDataNodes + 1).getId());
+        discoBuilder.clusterManagerNodeId(newNode(numberOfDataNodes + 1).getId());
         ClusterState.Builder state = ClusterState.builder(new ClusterName("test"));
         state.nodes(discoBuilder);
         Builder routingTableBuilder = RoutingTable.builder();
@@ -417,7 +417,7 @@ public static ClusterState stateWithActivePrimary(
     public static ClusterState stateWithNoShard() {
         DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
         discoBuilder.localNodeId(newNode(0).getId());
-        discoBuilder.masterNodeId(newNode(1).getId());
+        discoBuilder.clusterManagerNodeId(newNode(1).getId());
         ClusterState.Builder state = ClusterState.builder(new ClusterName("test"));
         state.nodes(discoBuilder);
         state.metadata(Metadata.builder().generateClusterUuidIfNeeded());
@@ -426,20 +426,20 @@ public static ClusterState stateWithNoShard() {
     }
 
     /**
-     * Creates a cluster state where local node and master node can be specified
+     * Creates a cluster state where local node and cluster-manager node can be specified
      *
      * @param localNode  node in allNodes that is the local node
-     * @param masterNode node in allNodes that is the master node. Can be null if no master exists
+     * @param clusterManagerNode node in allNodes that is the cluster-manager node. Can be null if no cluster-manager exists
      * @param allNodes   all nodes in the cluster
      * @return cluster state
      */
-    public static ClusterState state(DiscoveryNode localNode, DiscoveryNode masterNode, DiscoveryNode... allNodes) {
+    public static ClusterState state(DiscoveryNode localNode, DiscoveryNode clusterManagerNode, DiscoveryNode... allNodes) {
         DiscoveryNodes.Builder discoBuilder = DiscoveryNodes.builder();
         for (DiscoveryNode node : allNodes) {
             discoBuilder.add(node);
         }
-        if (masterNode != null) {
-            discoBuilder.masterNodeId(masterNode.getId());
+        if (clusterManagerNode != null) {
+            discoBuilder.clusterManagerNodeId(clusterManagerNode.getId());
         }
         discoBuilder.localNodeId(localNode.getId());
 
diff --git a/test/framework/src/main/java/org/opensearch/bootstrap/BootstrapForTesting.java b/test/framework/src/main/java/org/opensearch/bootstrap/BootstrapForTesting.java
index 4f135f2d14a75..8f065de35aa8b 100644
--- a/test/framework/src/main/java/org/opensearch/bootstrap/BootstrapForTesting.java
+++ b/test/framework/src/main/java/org/opensearch/bootstrap/BootstrapForTesting.java
@@ -33,17 +33,18 @@
 package org.opensearch.bootstrap;
 
 import com.carrotsearch.randomizedtesting.RandomizedRunner;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.common.Booleans;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.network.IfConfig;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.mockito.plugin.PriviledgedMockMaker;
 import org.opensearch.plugins.PluginInfo;
 import org.opensearch.secure_sm.SecureSM;
@@ -130,8 +131,9 @@ public class BootstrapForTesting {
                 // java.io.tmpdir
                 FilePermissionUtils.addDirectoryPath(perms, "java.io.tmpdir", javaTmpDir, "read,readlink,write,delete", false);
                 // custom test config file
-                if (Strings.hasLength(System.getProperty("tests.config"))) {
-                    FilePermissionUtils.addSingleFilePath(perms, PathUtils.get(System.getProperty("tests.config")), "read,readlink");
+                String testConfigFile = System.getProperty("tests.config");
+                if (Strings.hasLength(testConfigFile)) {
+                    FilePermissionUtils.addSingleFilePath(perms, PathUtils.get(testConfigFile), "read,readlink");
                 }
                 // intellij hack: intellij test runner wants setIO and will
                 // screw up all test logging without it!
diff --git a/test/framework/src/main/java/org/opensearch/client/RestClientBuilderTestCase.java b/test/framework/src/main/java/org/opensearch/client/RestClientBuilderTestCase.java
index 69710b8e5c848..e483a7df895bb 100644
--- a/test/framework/src/main/java/org/opensearch/client/RestClientBuilderTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/client/RestClientBuilderTestCase.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.client;
 
-import java.util.HashMap;
-import java.util.Map;
-
 import joptsimple.internal.Strings;
 import org.apache.http.Header;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.util.HashMap;
+import java.util.Map;
+
 /**
  * A test case with access to internals of a RestClient.
  */
diff --git a/test/framework/src/main/java/org/opensearch/cluster/DataStreamTestHelper.java b/test/framework/src/main/java/org/opensearch/cluster/DataStreamTestHelper.java
index af78fd36dceb4..c97260db43e80 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/DataStreamTestHelper.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/DataStreamTestHelper.java
@@ -40,7 +40,7 @@
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/cluster/MockInternalClusterInfoService.java b/test/framework/src/main/java/org/opensearch/cluster/MockInternalClusterInfoService.java
index 149d7ccdaaae0..6354cf18e8b62 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/MockInternalClusterInfoService.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/MockInternalClusterInfoService.java
@@ -114,7 +114,13 @@ List<NodeStats> adjustNodesStats(List<NodeStats> nodesStats) {
                 nodeStats.getAdaptiveSelectionStats(),
                 nodeStats.getScriptCacheStats(),
                 nodeStats.getIndexingPressureStats(),
-                nodeStats.getShardIndexingPressureStats()
+                nodeStats.getShardIndexingPressureStats(),
+                nodeStats.getSearchBackpressureStats(),
+                nodeStats.getClusterManagerThrottlingStats(),
+                nodeStats.getWeightedRoutingStats(),
+                nodeStats.getFileCacheStats(),
+                nodeStats.getTaskCancellationStats(),
+                nodeStats.getSearchPipelineStats()
             );
         }).collect(Collectors.toList());
     }
@@ -126,7 +132,8 @@ class SizeFakingClusterInfo extends ClusterInfo {
                 delegate.getNodeMostAvailableDiskUsages(),
                 delegate.shardSizes,
                 delegate.routingToDataPath,
-                delegate.reservedSpace
+                delegate.reservedSpace,
+                delegate.nodeFileCacheStats
             );
         }
 
diff --git a/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationTestCase.java b/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationTestCase.java
index e42dd42b18da5..f6113860e3907 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationTestCase.java
@@ -48,7 +48,6 @@
 import org.opensearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.opensearch.cluster.routing.allocation.decider.Decision;
 import org.opensearch.cluster.routing.allocation.decider.SameShardAllocationDecider;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.gateway.GatewayAllocator;
@@ -60,11 +59,14 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Formatter;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Random;
 import java.util.Set;
+import java.util.TreeMap;
 
 import static java.util.Collections.emptyMap;
 import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
@@ -75,9 +77,7 @@ public abstract class OpenSearchAllocationTestCase extends OpenSearchTestCase {
         ClusterSettings.BUILT_IN_CLUSTER_SETTINGS
     );
 
-    public static final SnapshotsInfoService SNAPSHOT_INFO_SERVICE_WITH_NO_SHARD_SIZES = () -> new SnapshotShardSizeInfo(
-        ImmutableOpenMap.of()
-    ) {
+    public static final SnapshotsInfoService SNAPSHOT_INFO_SERVICE_WITH_NO_SHARD_SIZES = () -> new SnapshotShardSizeInfo(Map.of()) {
         @Override
         public Long getShardSize(ShardRouting shardRouting) {
             assert shardRouting.recoverySource().getType() == RecoverySource.Type.SNAPSHOT
@@ -148,7 +148,7 @@ public static AllocationDeciders randomAllocationDeciders(Settings settings, Clu
         return new AllocationDeciders(deciders);
     }
 
-    protected static Set<DiscoveryNodeRole> MASTER_DATA_ROLES = Collections.unmodifiableSet(
+    protected static Set<DiscoveryNodeRole> CLUSTER_MANAGER_DATA_ROLES = Collections.unmodifiableSet(
         new HashSet<>(Arrays.asList(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE, DiscoveryNodeRole.DATA_ROLE))
     );
 
@@ -157,19 +157,23 @@ protected static DiscoveryNode newNode(String nodeId) {
     }
 
     protected static DiscoveryNode newNode(String nodeName, String nodeId, Map<String, String> attributes) {
-        return new DiscoveryNode(nodeName, nodeId, buildNewFakeTransportAddress(), attributes, MASTER_DATA_ROLES, Version.CURRENT);
+        return new DiscoveryNode(nodeName, nodeId, buildNewFakeTransportAddress(), attributes, CLUSTER_MANAGER_DATA_ROLES, Version.CURRENT);
     }
 
     protected static DiscoveryNode newNode(String nodeId, Map<String, String> attributes) {
-        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), attributes, MASTER_DATA_ROLES, Version.CURRENT);
+        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), attributes, CLUSTER_MANAGER_DATA_ROLES, Version.CURRENT);
     }
 
     protected static DiscoveryNode newNode(String nodeId, Set<DiscoveryNodeRole> roles) {
         return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
     }
 
+    protected static DiscoveryNode newNode(String nodeName, String nodeId, Set<DiscoveryNodeRole> roles) {
+        return new DiscoveryNode(nodeName, nodeId, buildNewFakeTransportAddress(), emptyMap(), roles, Version.CURRENT);
+    }
+
     protected static DiscoveryNode newNode(String nodeId, Version version) {
-        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), emptyMap(), MASTER_DATA_ROLES, version);
+        return new DiscoveryNode(nodeId, buildNewFakeTransportAddress(), emptyMap(), CLUSTER_MANAGER_DATA_ROLES, version);
     }
 
     protected static ClusterState startRandomInitializingShard(ClusterState clusterState, AllocationService strategy) {
@@ -302,6 +306,101 @@ public Decision canAllocate(ShardRouting shardRouting, RoutingAllocation allocat
         }
     }
 
+    /**
+     * Utility class to show shards distribution across nodes.
+     */
+    public static class ShardAllocations {
+
+        private static final String separator = "===================================================";
+        private static final String ONE_LINE_RETURN = "\n";
+        private static final String TWO_LINE_RETURN = "\n\n";
+
+        /**
+         Store shard primary/replica shard count against a node.
+         String: NodeId
+         int[]: tuple storing primary shard count in 0th index and replica's in 1st
+         */
+        static TreeMap<String, int[]> nodeToShardCountMap = new TreeMap<>();
+
+        /**
+         * Helper map containing NodeName to NodeId
+         */
+        static TreeMap<String, String> nameToNodeId = new TreeMap<>();
+
+        /*
+        Unassigned array containing primary at 0, replica at 1
+         */
+        static int[] unassigned = new int[2];
+
+        static int[] totalShards = new int[2];
+
+        private final static String printShardAllocationWithHeader(int[] shardCount) {
+            StringBuffer sb = new StringBuffer();
+            Formatter formatter = new Formatter(sb, Locale.getDefault());
+            formatter.format("%-20s %-20s\n", "P", shardCount[0]);
+            formatter.format("%-20s %-20s\n", "R", shardCount[1]);
+            return sb.toString();
+        }
+
+        private static void reset() {
+            nodeToShardCountMap.clear();
+            nameToNodeId.clear();
+            totalShards[0] = totalShards[1] = 0;
+            unassigned[0] = unassigned[1] = 0;
+        }
+
+        private static void buildMap(ClusterState inputState) {
+            reset();
+            for (RoutingNode node : inputState.getRoutingNodes()) {
+                if (node.node().getName() != null && node.node().getName().isEmpty() == false) {
+                    nameToNodeId.putIfAbsent(node.node().getName(), node.nodeId());
+                } else {
+                    nameToNodeId.putIfAbsent(node.nodeId(), node.nodeId());
+                }
+                nodeToShardCountMap.putIfAbsent(node.nodeId(), new int[] { 0, 0 });
+            }
+            for (ShardRouting shardRouting : inputState.routingTable().allShards()) {
+                // Fetch shard to update. Initialize local array
+                updateMap(nodeToShardCountMap, shardRouting);
+            }
+        }
+
+        private static void updateMap(TreeMap<String, int[]> mapToUpdate, ShardRouting shardRouting) {
+            int[] shard;
+            shard = shardRouting.assignedToNode() ? mapToUpdate.get(shardRouting.currentNodeId()) : unassigned;
+            // Update shard type count
+            if (shardRouting.primary()) {
+                shard[0]++;
+                totalShards[0]++;
+            } else {
+                shard[1]++;
+                totalShards[1]++;
+            }
+            // For assigned shards, put back counter
+            if (shardRouting.assignedToNode()) mapToUpdate.put(shardRouting.currentNodeId(), shard);
+        }
+
+        private static String allocation() {
+            StringBuffer sb = new StringBuffer();
+            sb.append(TWO_LINE_RETURN + separator + ONE_LINE_RETURN);
+            Formatter formatter = new Formatter(sb, Locale.getDefault());
+            for (Map.Entry<String, String> entry : nameToNodeId.entrySet()) {
+                String nodeId = nameToNodeId.get(entry.getKey());
+                formatter.format("%-20s\n", entry.getKey().toUpperCase(Locale.getDefault()));
+                sb.append(printShardAllocationWithHeader(nodeToShardCountMap.get(nodeId)));
+            }
+            sb.append(ONE_LINE_RETURN);
+            formatter.format("%-20s (P)%-5s (R)%-5s\n\n", "Unassigned ", unassigned[0], unassigned[1]);
+            formatter.format("%-20s (P)%-5s (R)%-5s\n\n", "Total Shards", totalShards[0], totalShards[1]);
+            return sb.toString();
+        }
+
+        public static String printShardDistribution(ClusterState state) {
+            buildMap(state);
+            return allocation();
+        }
+    }
+
     /** A lock {@link AllocationService} allowing tests to override time */
     protected static class MockAllocationService extends AllocationService {
 
diff --git a/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationWithConstraintsTestCase.java b/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationWithConstraintsTestCase.java
index 55f9f6947b999..7f1d1d3381751 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationWithConstraintsTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/OpenSearchAllocationWithConstraintsTestCase.java
@@ -14,7 +14,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.CollectionUtils;
+import org.opensearch.core.common.util.CollectionUtils;
 import org.junit.Before;
 
 import java.util.Arrays;
diff --git a/test/framework/src/main/java/org/opensearch/cluster/coordination/AbstractCoordinatorTestCase.java b/test/framework/src/main/java/org/opensearch/cluster/coordination/AbstractCoordinatorTestCase.java
index 9841daa5f81b7..d24cc24d28579 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/coordination/AbstractCoordinatorTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/coordination/AbstractCoordinatorTestCase.java
@@ -32,6 +32,7 @@
 package org.opensearch.cluster.coordination;
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
+
 import org.apache.logging.log4j.CloseableThreadContext;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -42,37 +43,40 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskListener;
 import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.NodeConnectionsService;
+import org.opensearch.cluster.OpenSearchAllocationTestCase;
 import org.opensearch.cluster.coordination.AbstractCoordinatorTestCase.Cluster.ClusterNode;
 import org.opensearch.cluster.coordination.CoordinationMetadata.VotingConfiguration;
 import org.opensearch.cluster.coordination.LinearizabilityChecker.History;
 import org.opensearch.cluster.coordination.LinearizabilityChecker.SequentialSpec;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterApplierService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.cluster.service.FakeThreadPoolMasterService;
+import org.opensearch.cluster.service.FakeThreadPoolClusterManagerService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.discovery.SeedHostsProvider;
 import org.opensearch.env.NodeEnvironment;
@@ -80,9 +84,11 @@
 import org.opensearch.gateway.GatewayService;
 import org.opensearch.gateway.MockGatewayMetaState;
 import org.opensearch.gateway.PersistedClusterStateService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.monitor.NodeHealthService;
 import org.opensearch.monitor.StatusInfo;
+import org.opensearch.node.remotestore.RemoteStoreNodeService;
+import org.opensearch.repositories.RepositoriesService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.disruption.DisruptableMockTransport;
 import org.opensearch.test.disruption.DisruptableMockTransport.ConnectionStatus;
@@ -139,7 +145,7 @@
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_INTERVAL_SETTING;
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING;
 import static org.opensearch.cluster.coordination.LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING;
-import static org.opensearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_ID;
+import static org.opensearch.cluster.coordination.NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_ID;
 import static org.opensearch.cluster.coordination.Reconfigurator.CLUSTER_AUTO_SHRINK_VOTING_CONFIGURATION;
 import static org.opensearch.discovery.PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_SETTING;
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
@@ -217,13 +223,13 @@ protected static int defaultInt(Setting<Integer> setting) {
     }
 
     // Updating the cluster state involves up to 7 delays:
-    // 1. submit the task to the master service
+    // 1. submit the task to the cluster-manager service
     // 2. send PublishRequest
     // 3. receive PublishResponse
     // 4. send ApplyCommitRequest
     // 5. apply committed cluster state
     // 6. receive ApplyCommitResponse
-    // 7. apply committed state on master (last one to apply cluster state)
+    // 7. apply committed state on cluster-manager (last one to apply cluster state)
     public static final long DEFAULT_CLUSTER_STATE_UPDATE_DELAY = 7 * DEFAULT_DELAY_VARIABILITY;
 
     private static final int ELECTION_RETRIES = 10;
@@ -288,11 +294,11 @@ class Cluster implements Releasable {
             this(initialNodeCount, true, Settings.EMPTY);
         }
 
-        Cluster(int initialNodeCount, boolean allNodesMasterEligible, Settings nodeSettings) {
-            this(initialNodeCount, allNodesMasterEligible, nodeSettings, () -> new StatusInfo(HEALTHY, "healthy-info"));
+        Cluster(int initialNodeCount, boolean allNodesclusterManagerEligible, Settings nodeSettings) {
+            this(initialNodeCount, allNodesclusterManagerEligible, nodeSettings, () -> new StatusInfo(HEALTHY, "healthy-info"));
         }
 
-        Cluster(int initialNodeCount, boolean allNodesMasterEligible, Settings nodeSettings, NodeHealthService nodeHealthService) {
+        Cluster(int initialNodeCount, boolean allNodesClusterManagerEligible, Settings nodeSettings, NodeHealthService nodeHealthService) {
             this.nodeHealthService = nodeHealthService;
             bigArrays = usually()
                 ? BigArrays.NON_RECYCLING_INSTANCE
@@ -301,29 +307,29 @@ class Cluster implements Releasable {
 
             assertThat(initialNodeCount, greaterThan(0));
 
-            final Set<String> masterEligibleNodeIds = new HashSet<>(initialNodeCount);
+            final Set<String> clusterManagerEligibleNodeIds = new HashSet<>(initialNodeCount);
             clusterNodes = new ArrayList<>(initialNodeCount);
             for (int i = 0; i < initialNodeCount; i++) {
                 final ClusterNode clusterNode = new ClusterNode(
                     nextNodeIndex.getAndIncrement(),
-                    allNodesMasterEligible || i == 0 || randomBoolean(),
+                    allNodesClusterManagerEligible || i == 0 || randomBoolean(),
                     nodeSettings,
                     nodeHealthService
                 );
                 clusterNodes.add(clusterNode);
-                if (clusterNode.getLocalNode().isMasterNode()) {
-                    masterEligibleNodeIds.add(clusterNode.getId());
+                if (clusterNode.getLocalNode().isClusterManagerNode()) {
+                    clusterManagerEligibleNodeIds.add(clusterNode.getId());
                 }
             }
 
             initialConfiguration = new VotingConfiguration(
-                new HashSet<>(randomSubsetOf(randomIntBetween(1, masterEligibleNodeIds.size()), masterEligibleNodeIds))
+                new HashSet<>(randomSubsetOf(randomIntBetween(1, clusterManagerEligibleNodeIds.size()), clusterManagerEligibleNodeIds))
             );
 
             logger.info(
-                "--> creating cluster of {} nodes (master-eligible nodes: {}) with initial configuration {}",
+                "--> creating cluster of {} nodes (cluster-manager-eligible nodes: {}) with initial configuration {}",
                 initialNodeCount,
-                masterEligibleNodeIds,
+                clusterManagerEligibleNodeIds,
                 initialConfiguration
             );
         }
@@ -336,7 +342,7 @@ void addNodesAndStabilise(int newNodesCount) {
 
             addNodes(newNodesCount);
             stabilise(
-                // The first pinging discovers the master
+                // The first pinging discovers the cluster-manager
                 defaultMillis(DISCOVERY_FIND_PEERS_INTERVAL_SETTING)
                     // One message delay to send a join
                     + DEFAULT_DELAY_VARIABILITY
@@ -557,7 +563,7 @@ void stabilise(long stabilisationDurationMillis) {
             final ClusterNode leader = getAnyLeader();
             final long leaderTerm = leader.coordinator.getCurrentTerm();
 
-            final int pendingTaskCount = leader.masterService.getFakeMasterServicePendingTaskCount();
+            final int pendingTaskCount = leader.clusterManagerService.getFakeMasterServicePendingTaskCount();
             runFor((pendingTaskCount + 1) * DEFAULT_CLUSTER_STATE_UPDATE_DELAY, "draining task queue");
 
             final Matcher<Long> isEqualToLeaderVersion = equalTo(leader.coordinator.getLastAcceptedState().getVersion());
@@ -566,8 +572,8 @@ void stabilise(long stabilisationDurationMillis) {
             assertTrue(leaderId + " has been bootstrapped", leader.coordinator.isInitialConfigurationSet());
             assertTrue(leaderId + " exists in its last-applied state", leader.getLastAppliedClusterState().getNodes().nodeExists(leaderId));
             assertThat(
-                leaderId + " has no NO_MASTER_BLOCK",
-                leader.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_MASTER_BLOCK_ID),
+                leaderId + " has no NO_CLUSTER_MANAGER_BLOCK",
+                leader.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_CLUSTER_MANAGER_BLOCK_ID),
                 equalTo(false)
             );
             assertThat(
@@ -616,13 +622,13 @@ void stabilise(long stabilisationDurationMillis) {
                     );
                     assertTrue(nodeId + " has been bootstrapped", clusterNode.coordinator.isInitialConfigurationSet());
                     assertThat(
-                        nodeId + " has correct master",
-                        clusterNode.getLastAppliedClusterState().nodes().getMasterNode(),
+                        nodeId + " has correct cluster-manager",
+                        clusterNode.getLastAppliedClusterState().nodes().getClusterManagerNode(),
                         equalTo(leader.getLocalNode())
                     );
                     assertThat(
-                        nodeId + " has no NO_MASTER_BLOCK",
-                        clusterNode.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_MASTER_BLOCK_ID),
+                        nodeId + " has no NO_CLUSTER_MANAGER_BLOCK",
+                        clusterNode.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_CLUSTER_MANAGER_BLOCK_ID),
                         equalTo(false)
                     );
                     assertThat(
@@ -632,10 +638,14 @@ void stabilise(long stabilisationDurationMillis) {
                     );
                 } else {
                     assertThat(nodeId + " is not following " + leaderId, clusterNode.coordinator.getMode(), is(CANDIDATE));
-                    assertThat(nodeId + " has no master", clusterNode.getLastAppliedClusterState().nodes().getMasterNode(), nullValue());
                     assertThat(
-                        nodeId + " has NO_MASTER_BLOCK",
-                        clusterNode.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_MASTER_BLOCK_ID),
+                        nodeId + " has no cluster-manager",
+                        clusterNode.getLastAppliedClusterState().nodes().getClusterManagerNode(),
+                        nullValue()
+                    );
+                    assertThat(
+                        nodeId + " has NO_CLUSTER_MANAGER_BLOCK",
+                        clusterNode.getLastAppliedClusterState().blocks().hasGlobalBlockWithId(NO_CLUSTER_MANAGER_BLOCK_ID),
                         equalTo(true)
                     );
                     assertFalse(
@@ -780,7 +790,7 @@ boolean nodeExists(DiscoveryNode node) {
         ClusterNode getAnyBootstrappableNode() {
             return randomFrom(
                 clusterNodes.stream()
-                    .filter(n -> n.getLocalNode().isMasterNode())
+                    .filter(n -> n.getLocalNode().isClusterManagerNode())
                     .filter(n -> initialConfiguration.getNodeIds().contains(n.getLocalNode().getId()))
                     .collect(Collectors.toList())
             );
@@ -835,14 +845,16 @@ class MockPersistedState implements CoordinationState.PersistedState {
             private final CoordinationState.PersistedState delegate;
             private final NodeEnvironment nodeEnvironment;
 
+            private MockGatewayMetaState mockGatewayMetaState;
+
             MockPersistedState(DiscoveryNode localNode) {
                 try {
                     if (rarely()) {
                         nodeEnvironment = newNodeEnvironment();
                         nodeEnvironments.add(nodeEnvironment);
-                        final MockGatewayMetaState gatewayMetaState = new MockGatewayMetaState(localNode, bigArrays);
-                        gatewayMetaState.start(Settings.EMPTY, nodeEnvironment, xContentRegistry());
-                        delegate = gatewayMetaState.getPersistedState();
+                        mockGatewayMetaState = new MockGatewayMetaState(localNode, bigArrays);
+                        mockGatewayMetaState.start(Settings.EMPTY, nodeEnvironment, xContentRegistry(), persistedStateRegistry());
+                        delegate = mockGatewayMetaState.getPersistedState();
                     } else {
                         nodeEnvironment = null;
                         delegate = new InMemoryPersistedState(
@@ -859,11 +871,12 @@ class MockPersistedState implements CoordinationState.PersistedState {
 
             MockPersistedState(
                 DiscoveryNode newLocalNode,
-                MockPersistedState oldState,
+                PersistedStateRegistry persistedStateRegistry,
                 Function<Metadata, Metadata> adaptGlobalMetadata,
                 Function<Long, Long> adaptCurrentTerm
             ) {
                 try {
+                    MockPersistedState oldState = (MockPersistedState) persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL);
                     if (oldState.nodeEnvironment != null) {
                         nodeEnvironment = oldState.nodeEnvironment;
                         final Metadata updatedMetadata = adaptGlobalMetadata.apply(oldState.getLastAcceptedState().metadata());
@@ -885,7 +898,7 @@ class MockPersistedState implements CoordinationState.PersistedState {
                             }
                         }
                         final MockGatewayMetaState gatewayMetaState = new MockGatewayMetaState(newLocalNode, bigArrays);
-                        gatewayMetaState.start(Settings.EMPTY, nodeEnvironment, xContentRegistry());
+                        gatewayMetaState.start(Settings.EMPTY, nodeEnvironment, xContentRegistry(), persistedStateRegistry());
                         delegate = gatewayMetaState.getPersistedState();
                     } else {
                         nodeEnvironment = null;
@@ -894,8 +907,9 @@ class MockPersistedState implements CoordinationState.PersistedState {
 
                         final long persistedCurrentTerm;
 
-                        if ( // node is master-ineligible either before or after the restart ...
-                        (oldState.getLastAcceptedState().nodes().getLocalNode().isMasterNode() && newLocalNode.isMasterNode()) == false
+                        if ( // node is cluster-manager-ineligible either before or after the restart ...
+                        (oldState.getLastAcceptedState().nodes().getLocalNode().isClusterManagerNode()
+                            && newLocalNode.isClusterManagerNode()) == false
                             // ... and it's accepted some non-initial state so we can roll back ...
                             && (oldState.getLastAcceptedState().term() > 0L || oldState.getLastAcceptedState().version() > 0L)
                             // ... and we're feeling lucky ...
@@ -926,7 +940,7 @@ && randomBoolean()) {
                             final long newValue = randomLong();
 
                             logger.trace(
-                                "rolling back persisted cluster state on master-ineligible node [{}]: "
+                                "rolling back persisted cluster state on cluster-manager-ineligible node [{}]: "
                                     + "previously currentTerm={}, lastAcceptedTerm={}, lastAcceptedVersion={} "
                                     + "but now currentTerm={}, lastAcceptedTerm={}, lastAcceptedVersion={}",
                                 newLocalNode,
@@ -1019,20 +1033,22 @@ class ClusterNode {
             private final int nodeIndex;
             Coordinator coordinator;
             private final DiscoveryNode localNode;
-            final MockPersistedState persistedState;
+            final PersistedStateRegistry persistedStateRegistry;
             final Settings nodeSettings;
-            private AckedFakeThreadPoolMasterService masterService;
+            private AckedFakeThreadPoolClusterManagerService clusterManagerService;
             private DisruptableClusterApplierService clusterApplierService;
             private ClusterService clusterService;
             TransportService transportService;
             private DisruptableMockTransport mockTransport;
             private NodeHealthService nodeHealthService;
+            private RepositoriesService repositoriesService;
+            private RemoteStoreNodeService remoteStoreNodeService;
             List<BiConsumer<DiscoveryNode, ClusterState>> extraJoinValidators = new ArrayList<>();
 
-            ClusterNode(int nodeIndex, boolean masterEligible, Settings nodeSettings, NodeHealthService nodeHealthService) {
+            ClusterNode(int nodeIndex, boolean clusterManagerEligible, Settings nodeSettings, NodeHealthService nodeHealthService) {
                 this(
                     nodeIndex,
-                    createDiscoveryNode(nodeIndex, masterEligible),
+                    createDiscoveryNode(nodeIndex, clusterManagerEligible),
                     defaultPersistedStateSupplier,
                     nodeSettings,
                     nodeHealthService
@@ -1050,7 +1066,9 @@ class ClusterNode {
                 this.nodeIndex = nodeIndex;
                 this.localNode = localNode;
                 this.nodeSettings = nodeSettings;
-                persistedState = persistedStateSupplier.apply(localNode);
+                final MockPersistedState persistedState = persistedStateSupplier.apply(localNode);
+                persistedStateRegistry = persistedStateRegistry();
+                persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, persistedState);
                 assertTrue("must use a fresh PersistedState", openPersistedStates.add(persistedState));
                 boolean success = false;
                 try {
@@ -1099,9 +1117,10 @@ protected Optional<DisruptableMockTransport> getDisruptableMockTransport(Transpo
                     getTransportInterceptor(localNode, threadPool),
                     a -> localNode,
                     null,
-                    emptySet()
+                    emptySet(),
+                    NoopTracer.INSTANCE
                 );
-                masterService = new AckedFakeThreadPoolMasterService(
+                clusterManagerService = new AckedFakeThreadPoolClusterManagerService(
                     localNode.getId(),
                     "test",
                     threadPool,
@@ -1115,10 +1134,19 @@ protected Optional<DisruptableMockTransport> getDisruptableMockTransport(Transpo
                     deterministicTaskQueue,
                     threadPool
                 );
-                clusterService = new ClusterService(settings, clusterSettings, masterService, clusterApplierService);
+                clusterService = new ClusterService(settings, clusterSettings, clusterManagerService, clusterApplierService);
                 clusterService.setNodeConnectionsService(
                     new NodeConnectionsService(clusterService.getSettings(), threadPool, transportService)
                 );
+                repositoriesService = new RepositoriesService(
+                    settings,
+                    clusterService,
+                    transportService,
+                    Collections.emptyMap(),
+                    Collections.emptyMap(),
+                    threadPool
+                );
+                remoteStoreNodeService = new RemoteStoreNodeService(new SetOnce<>(repositoriesService)::get, threadPool);
                 final Collection<BiConsumer<DiscoveryNode, ClusterState>> onJoinValidators = Collections.singletonList(
                     (dn, cs) -> extraJoinValidators.forEach(validator -> validator.accept(dn, cs))
                 );
@@ -1130,7 +1158,7 @@ protected Optional<DisruptableMockTransport> getDisruptableMockTransport(Transpo
                     transportService,
                     writableRegistry(),
                     allocationService,
-                    masterService,
+                    clusterManagerService,
                     this::getPersistedState,
                     Cluster.this::provideSeedHosts,
                     clusterApplierService,
@@ -1138,9 +1166,11 @@ protected Optional<DisruptableMockTransport> getDisruptableMockTransport(Transpo
                     Randomness.get(),
                     (s, p, r) -> {},
                     getElectionStrategy(),
-                    nodeHealthService
+                    nodeHealthService,
+                    persistedStateRegistry,
+                    remoteStoreNodeService
                 );
-                masterService.setClusterStatePublisher(coordinator);
+                clusterManagerService.setClusterStatePublisher(coordinator);
                 final GatewayService gatewayService = new GatewayService(
                     settings,
                     allocationService,
@@ -1190,20 +1220,22 @@ ClusterNode restartedNode(
                     address.getAddress(),
                     address,
                     Collections.emptyMap(),
-                    localNode.isMasterNode() && DiscoveryNode.isMasterNode(nodeSettings) ? DiscoveryNodeRole.BUILT_IN_ROLES : emptySet(),
+                    localNode.isClusterManagerNode() && DiscoveryNode.isClusterManagerNode(nodeSettings)
+                        ? DiscoveryNodeRole.BUILT_IN_ROLES
+                        : emptySet(),
                     Version.CURRENT
                 );
                 return new ClusterNode(
                     nodeIndex,
                     newLocalNode,
-                    node -> new MockPersistedState(newLocalNode, persistedState, adaptGlobalMetadata, adaptCurrentTerm),
+                    node -> new MockPersistedState(newLocalNode, persistedStateRegistry, adaptGlobalMetadata, adaptCurrentTerm),
                     nodeSettings,
                     nodeHealthService
                 );
             }
 
             private CoordinationState.PersistedState getPersistedState() {
-                return persistedState;
+                return persistedStateRegistry.getPersistedState(PersistedStateType.LOCAL);
             }
 
             String getId() {
@@ -1257,7 +1289,7 @@ public String toString() {
 
             void submitSetAutoShrinkVotingConfiguration(final boolean autoShrinkVotingConfiguration) {
                 submitUpdateTask(
-                    "set master nodes failure tolerance [" + autoShrinkVotingConfiguration + "]",
+                    "set cluster-manager nodes failure tolerance [" + autoShrinkVotingConfiguration + "]",
                     cs -> ClusterState.builder(cs)
                         .metadata(
                             Metadata.builder(cs.metadata())
@@ -1287,7 +1319,7 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
                     }
 
                     @Override
-                    public void onNoLongerMaster(String source) {
+                    public void onNoLongerClusterManager(String source) {
                         // in this case, we know for sure that event was not processed by the system and will not change history
                         // remove event to help avoid bloated history and state space explosion in linearizability checker
                         history.remove(eventId);
@@ -1327,11 +1359,11 @@ AckCollector submitUpdateTask(
                 onNode(() -> {
                     logger.trace("[{}] submitUpdateTask: enqueueing [{}]", localNode.getId(), source);
                     final long submittedTerm = coordinator.getCurrentTerm();
-                    masterService.submitStateUpdateTask(source, new ClusterStateUpdateTask() {
+                    clusterManagerService.submitStateUpdateTask(source, new ClusterStateUpdateTask() {
                         @Override
                         public ClusterState execute(ClusterState currentState) {
                             assertThat(currentState.term(), greaterThanOrEqualTo(submittedTerm));
-                            masterService.nextAckCollector = ackCollector;
+                            clusterManagerService.nextAckCollector = ackCollector;
                             return clusterStateUpdate.apply(currentState);
                         }
 
@@ -1342,9 +1374,9 @@ public void onFailure(String source, Exception e) {
                         }
 
                         @Override
-                        public void onNoLongerMaster(String source) {
-                            logger.trace("no longer master: [{}]", source);
-                            taskListener.onNoLongerMaster(source);
+                        public void onNoLongerClusterManager(String source) {
+                            logger.trace("no longer cluster-manager: [{}]", source);
+                            taskListener.onNoLongerClusterManager(source);
                         }
 
                         @Override
@@ -1423,7 +1455,7 @@ void applyInitialConfiguration() {
             }
 
             private boolean isNotUsefullyBootstrapped() {
-                return getLocalNode().isMasterNode() == false || coordinator.isInitialConfigurationSet() == false;
+                return getLocalNode().isClusterManagerNode() == false || coordinator.isInitialConfigurationSet() == false;
             }
 
             void allowClusterStateApplicationFailure() {
@@ -1506,11 +1538,11 @@ int getSuccessfulAckIndex(ClusterNode clusterNode) {
         }
     }
 
-    static class AckedFakeThreadPoolMasterService extends FakeThreadPoolMasterService {
+    static class AckedFakeThreadPoolClusterManagerService extends FakeThreadPoolClusterManagerService {
 
         AckCollector nextAckCollector = new AckCollector();
 
-        AckedFakeThreadPoolMasterService(
+        AckedFakeThreadPoolClusterManagerService(
             String nodeName,
             String serviceName,
             ThreadPool threadPool,
@@ -1606,7 +1638,7 @@ void allowClusterStateApplicationFailure() {
         }
     }
 
-    protected DiscoveryNode createDiscoveryNode(int nodeIndex, boolean masterEligible) {
+    protected DiscoveryNode createDiscoveryNode(int nodeIndex, boolean clusterManagerEligible) {
         final TransportAddress address = buildNewFakeTransportAddress();
         return new DiscoveryNode(
             "",
@@ -1616,7 +1648,7 @@ protected DiscoveryNode createDiscoveryNode(int nodeIndex, boolean masterEligibl
             address.getAddress(),
             address,
             Collections.emptyMap(),
-            masterEligible ? DiscoveryNodeRole.BUILT_IN_ROLES : emptySet(),
+            clusterManagerEligible ? DiscoveryNodeRole.BUILT_IN_ROLES : emptySet(),
             Version.CURRENT
         );
     }
diff --git a/test/framework/src/main/java/org/opensearch/cluster/coordination/CoordinationStateTestCluster.java b/test/framework/src/main/java/org/opensearch/cluster/coordination/CoordinationStateTestCluster.java
index 291eee501c4df..cbe695cbb2136 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/coordination/CoordinationStateTestCluster.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/coordination/CoordinationStateTestCluster.java
@@ -34,6 +34,7 @@
 
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.PersistedStateRegistry.PersistedStateType;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
@@ -48,9 +49,7 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static com.carrotsearch.randomizedtesting.RandomizedTest.rarely;
 import static java.util.stream.Collectors.toSet;
-import static org.apache.lucene.tests.util.LuceneTestCase.random;
 import static org.opensearch.test.OpenSearchTestCase.randomBoolean;
 import static org.opensearch.test.OpenSearchTestCase.randomFrom;
 import static org.opensearch.test.OpenSearchTestCase.randomIntBetween;
@@ -58,6 +57,8 @@
 import static org.opensearch.test.OpenSearchTestCase.randomLongBetween;
 import static org.opensearch.test.OpenSearchTestCase.randomSubsetOf;
 import static org.hamcrest.Matchers.hasSize;
+import static com.carrotsearch.randomizedtesting.RandomizedTest.rarely;
+import static org.apache.lucene.tests.util.LuceneTestCase.random;
 import static org.junit.Assert.assertThat;
 
 public class CoordinationStateTestCluster {
@@ -128,6 +129,8 @@ static class ClusterNode {
 
         DiscoveryNode localNode;
         CoordinationState.PersistedState persistedState;
+        PersistedStateRegistry persistedStateRegistry;
+
         CoordinationState state;
 
         ClusterNode(DiscoveryNode localNode, ElectionStrategy electionStrategy) {
@@ -143,19 +146,22 @@ static class ClusterNode {
                     0L
                 )
             );
+            persistedStateRegistry = new PersistedStateRegistry();
+            persistedStateRegistry.addPersistedState(PersistedStateType.LOCAL, persistedState);
+
             this.electionStrategy = electionStrategy;
-            state = new CoordinationState(localNode, persistedState, electionStrategy);
+            state = new CoordinationState(localNode, persistedStateRegistry, electionStrategy, Settings.EMPTY);
         }
 
         void reboot() {
-            if (localNode.isMasterNode() == false && rarely()) {
-                // master-ineligible nodes can't be trusted to persist the cluster state properly, but will not lose the fact that they
-                // were bootstrapped
+            if (localNode.isClusterManagerNode() == false && rarely()) {
+                // cluster-manager-ineligible nodes can't be trusted to persist the cluster state properly,
+                // but will not lose the fact that they were bootstrapped
                 final CoordinationMetadata.VotingConfiguration votingConfiguration = persistedState.getLastAcceptedState()
                     .getLastAcceptedConfiguration()
                     .isEmpty()
                         ? CoordinationMetadata.VotingConfiguration.EMPTY_CONFIG
-                        : CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_MASTER;
+                        : CoordinationMetadata.VotingConfiguration.MUST_JOIN_ELECTED_CLUSTER_MANAGER;
                 persistedState = new InMemoryPersistedState(
                     0L,
                     clusterState(0L, 0L, localNode, votingConfiguration, votingConfiguration, 0L)
@@ -183,7 +189,7 @@ void reboot() {
                 localNode.getVersion()
             );
 
-            state = new CoordinationState(localNode, persistedState, electionStrategy);
+            state = new CoordinationState(localNode, persistedStateRegistry, electionStrategy, Settings.EMPTY);
         }
 
         void setInitialState(CoordinationMetadata.VotingConfiguration initialConfig, long initialValue) {
@@ -285,11 +291,11 @@ void runRandomly() {
                 } else if (rarely() && rarely()) {
                     randomFrom(clusterNodes).reboot();
                 } else if (rarely()) {
-                    final List<ClusterNode> masterNodes = clusterNodes.stream()
+                    final List<ClusterNode> clusterManangerNodes = clusterNodes.stream()
                         .filter(cn -> cn.state.electionWon())
                         .collect(Collectors.toList());
-                    if (masterNodes.isEmpty() == false) {
-                        final ClusterNode clusterNode = randomFrom(masterNodes);
+                    if (clusterManangerNodes.isEmpty() == false) {
+                        final ClusterNode clusterNode = randomFrom(clusterManangerNodes);
                         final long term = rarely() ? randomLongBetween(0, maxTerm + 1) : clusterNode.state.getCurrentTerm();
                         final long version = rarely() ? randomIntBetween(0, 5) : clusterNode.state.getLastPublishedVersion() + 1;
                         final CoordinationMetadata.VotingConfiguration acceptedConfig = rarely()
@@ -323,13 +329,15 @@ void runRandomly() {
     }
 
     void invariant() {
-        // one master per term
+        // one cluster-manager per term
         messages.stream()
             .filter(m -> m.payload instanceof PublishRequest)
             .collect(Collectors.groupingBy(m -> ((PublishRequest) m.payload).getAcceptedState().term()))
             .forEach((term, publishMessages) -> {
-                Set<DiscoveryNode> mastersForTerm = publishMessages.stream().collect(Collectors.groupingBy(m -> m.sourceNode)).keySet();
-                assertThat("Multiple masters " + mastersForTerm + " for term " + term, mastersForTerm, hasSize(1));
+                Set<DiscoveryNode> clusterManagersForTerm = publishMessages.stream()
+                    .collect(Collectors.groupingBy(m -> m.sourceNode))
+                    .keySet();
+                assertThat("Multiple cluster-managers " + clusterManagersForTerm + " for term " + term, clusterManagersForTerm, hasSize(1));
             });
 
         // unique cluster state per (term, version) pair
diff --git a/test/framework/src/main/java/org/opensearch/cluster/coordination/DeterministicTaskQueue.java b/test/framework/src/main/java/org/opensearch/cluster/coordination/DeterministicTaskQueue.java
index 0c99d1f754944..1ad18bf89d5ba 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/coordination/DeterministicTaskQueue.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/coordination/DeterministicTaskQueue.java
@@ -33,6 +33,7 @@
 package org.opensearch.cluster.coordination;
 
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.settings.Settings;
diff --git a/test/framework/src/main/java/org/opensearch/cluster/coordination/LinearizabilityChecker.java b/test/framework/src/main/java/org/opensearch/cluster/coordination/LinearizabilityChecker.java
index 72434b33ae39f..60aacb83e0dc1 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/coordination/LinearizabilityChecker.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/coordination/LinearizabilityChecker.java
@@ -31,12 +31,11 @@
 
 package org.opensearch.cluster.coordination;
 
-import com.carrotsearch.hppc.LongObjectHashMap;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.FixedBitSet;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
+import org.opensearch.core.common.Strings;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -498,7 +497,7 @@ void unlift() {
      */
     private static class Cache {
         private final Map<Object, Set<FixedBitSet>> largeMap = new HashMap<>();
-        private final LongObjectHashMap<Set<Object>> smallMap = new LongObjectHashMap<>();
+        private final Map<Long, Set<Object>> smallMap = new HashMap<>();
         private final Map<Object, Object> internalizeStateMap = new HashMap<>();
         private final Map<Set<Object>, Set<Object>> statePermutations = new HashMap<>();
 
@@ -517,12 +516,11 @@ private boolean addInternal(Object state, FixedBitSet bitSet) {
         }
 
         private boolean addSmall(Object state, long bits) {
-            int index = smallMap.indexOf(bits);
-            Set<Object> states;
-            if (index < 0) {
-                states = Collections.singleton(state);
+            Set<Object> states = smallMap.get(bits);
+            if (states == null) {
+                states = Set.of(state);
             } else {
-                Set<Object> oldStates = smallMap.indexGet(index);
+                Set<Object> oldStates = states;
                 if (oldStates.contains(state)) return false;
                 states = new HashSet<>(oldStates.size() + 1);
                 states.addAll(oldStates);
@@ -532,12 +530,7 @@ private boolean addSmall(Object state, long bits) {
             // Get a unique set object per state permutation. We assume that the number of permutations of states are small.
             // We thus avoid the overhead of the set data structure.
             states = statePermutations.computeIfAbsent(states, k -> k);
-
-            if (index < 0) {
-                smallMap.indexInsert(index, bits, states);
-            } else {
-                smallMap.indexReplace(index, states);
-            }
+            smallMap.put(bits, states);
 
             return true;
         }
diff --git a/test/framework/src/main/java/org/opensearch/cluster/routing/ShardRoutingHelper.java b/test/framework/src/main/java/org/opensearch/cluster/routing/ShardRoutingHelper.java
index ccd686210e8d9..6df189081cfa4 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/routing/ShardRoutingHelper.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/routing/ShardRoutingHelper.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.cluster.routing;
 
-import org.opensearch.cluster.routing.RecoverySource.SnapshotRecoverySource;
-
 /**
  * A helper class that allows access to package private APIs for testing.
  */
@@ -77,7 +75,7 @@ public static ShardRouting moveToUnassigned(ShardRouting routing, UnassignedInfo
         return routing.moveToUnassigned(info);
     }
 
-    public static ShardRouting newWithRestoreSource(ShardRouting routing, SnapshotRecoverySource recoverySource) {
+    public static ShardRouting newWithRestoreSource(ShardRouting routing, RecoverySource recoverySource) {
         return new ShardRouting(
             routing.shardId(),
             routing.currentNodeId(),
diff --git a/test/framework/src/main/java/org/opensearch/cluster/routing/TestShardRouting.java b/test/framework/src/main/java/org/opensearch/cluster/routing/TestShardRouting.java
index 29207cbc4ada1..f67108345550f 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/routing/TestShardRouting.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/routing/TestShardRouting.java
@@ -35,14 +35,14 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.UUIDs;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.test.OpenSearchTestCase;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.random;
 import static org.opensearch.test.OpenSearchTestCase.randomAlphaOfLength;
+import static org.apache.lucene.tests.util.LuceneTestCase.random;
 
 /**
  * A helper that allows to create shard routing instances within tests, while not requiring to expose
@@ -205,6 +205,28 @@ public static ShardRouting newShardRouting(
         );
     }
 
+    public static ShardRouting newShardRouting(
+        ShardId shardId,
+        String currentNodeId,
+        String relocatingNodeId,
+        boolean primary,
+        ShardRoutingState state,
+        RecoverySource recoverySource,
+        UnassignedInfo unassignedInfo
+    ) {
+        return new ShardRouting(
+            shardId,
+            currentNodeId,
+            relocatingNodeId,
+            primary,
+            state,
+            recoverySource,
+            unassignedInfo,
+            buildAllocationId(state),
+            -1
+        );
+    }
+
     public static ShardRouting relocate(ShardRouting shardRouting, String relocatingNodeId, long expectedShardSize) {
         return shardRouting.relocate(relocatingNodeId, expectedShardSize);
     }
diff --git a/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerService.java b/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerService.java
new file mode 100644
index 0000000000000..3ca938c99b5fd
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerService.java
@@ -0,0 +1,213 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.ClusterStatePublisher.AckListener;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
+import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.node.Node;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+import static org.opensearch.test.OpenSearchTestCase.randomInt;
+import static org.apache.lucene.tests.util.LuceneTestCase.random;
+
+public class FakeThreadPoolClusterManagerService extends ClusterManagerService {
+    private static final Logger logger = LogManager.getLogger(FakeThreadPoolClusterManagerService.class);
+
+    private final String name;
+    private final List<Runnable> pendingTasks = new ArrayList<>();
+    private final Consumer<Runnable> onTaskAvailableToRun;
+    private boolean scheduledNextTask = false;
+    private boolean taskInProgress = false;
+    private boolean waitForPublish = false;
+
+    public FakeThreadPoolClusterManagerService(
+        String nodeName,
+        String serviceName,
+        ThreadPool threadPool,
+        Consumer<Runnable> onTaskAvailableToRun
+    ) {
+        super(
+            Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), nodeName).build(),
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
+            threadPool
+        );
+        this.name = serviceName;
+        this.onTaskAvailableToRun = onTaskAvailableToRun;
+    }
+
+    @Override
+    protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
+        return new PrioritizedOpenSearchThreadPoolExecutor(
+            name,
+            1,
+            1,
+            1,
+            TimeUnit.SECONDS,
+            OpenSearchExecutors.daemonThreadFactory(name),
+            null,
+            null
+        ) {
+
+            @Override
+            public void execute(Runnable command, final TimeValue timeout, final Runnable timeoutCallback) {
+                execute(command);
+            }
+
+            @Override
+            public void execute(Runnable command) {
+                pendingTasks.add(command);
+                scheduleNextTaskIfNecessary();
+            }
+        };
+    }
+
+    public int getFakeMasterServicePendingTaskCount() {
+        return pendingTasks.size();
+    }
+
+    private void scheduleNextTaskIfNecessary() {
+        if (taskInProgress == false && pendingTasks.isEmpty() == false && scheduledNextTask == false) {
+            scheduledNextTask = true;
+            onTaskAvailableToRun.accept(new Runnable() {
+                @Override
+                public String toString() {
+                    return "cluster-manager service scheduling next task";
+                }
+
+                @Override
+                public void run() {
+                    assert taskInProgress == false;
+                    assert waitForPublish == false;
+                    assert scheduledNextTask;
+                    final int taskIndex = randomInt(pendingTasks.size() - 1);
+                    logger.debug("next cluster-manager service task: choosing task {} of {}", taskIndex, pendingTasks.size());
+                    final Runnable task = pendingTasks.remove(taskIndex);
+                    taskInProgress = true;
+                    scheduledNextTask = false;
+                    final ThreadContext threadContext = threadPool.getThreadContext();
+                    try (ThreadContext.StoredContext ignored = threadContext.stashContext()) {
+                        threadContext.markAsSystemContext();
+                        task.run();
+                    }
+                    if (waitForPublish == false) {
+                        taskInProgress = false;
+                    }
+                    FakeThreadPoolClusterManagerService.this.scheduleNextTaskIfNecessary();
+                }
+            });
+        }
+    }
+
+    @Override
+    public ClusterState.Builder incrementVersion(ClusterState clusterState) {
+        // generate cluster UUID deterministically for repeatable tests
+        return ClusterState.builder(clusterState).incrementVersion().stateUUID(UUIDs.randomBase64UUID(random()));
+    }
+
+    @Override
+    protected void publish(ClusterChangedEvent clusterChangedEvent, TaskOutputs taskOutputs, long startTimeMillis) {
+        assert waitForPublish == false;
+        waitForPublish = true;
+        final AckListener ackListener = taskOutputs.createAckListener(threadPool, clusterChangedEvent.state());
+        final ActionListener<Void> publishListener = new ActionListener<Void>() {
+
+            private boolean listenerCalled = false;
+
+            @Override
+            public void onResponse(Void aVoid) {
+                assert listenerCalled == false;
+                listenerCalled = true;
+                assert waitForPublish;
+                waitForPublish = false;
+                try {
+                    onPublicationSuccess(clusterChangedEvent, taskOutputs);
+                } finally {
+                    taskInProgress = false;
+                    scheduleNextTaskIfNecessary();
+                }
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                assert listenerCalled == false;
+                listenerCalled = true;
+                assert waitForPublish;
+                waitForPublish = false;
+                try {
+                    onPublicationFailed(clusterChangedEvent, taskOutputs, startTimeMillis, e);
+                } finally {
+                    taskInProgress = false;
+                    scheduleNextTaskIfNecessary();
+                }
+            }
+        };
+        threadPool.generic().execute(threadPool.getThreadContext().preserveContext(new Runnable() {
+            @Override
+            public void run() {
+                clusterStatePublisher.publish(clusterChangedEvent, publishListener, wrapAckListener(ackListener));
+            }
+
+            @Override
+            public String toString() {
+                return "publish change of cluster state from version ["
+                    + clusterChangedEvent.previousState().version()
+                    + "] in term ["
+                    + clusterChangedEvent.previousState().term()
+                    + "] to version ["
+                    + clusterChangedEvent.state().version()
+                    + "] in term ["
+                    + clusterChangedEvent.state().term()
+                    + "]";
+            }
+        }));
+    }
+
+    protected AckListener wrapAckListener(AckListener ackListener) {
+        return ackListener;
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolMasterService.java b/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolMasterService.java
index 14d9f9554004f..0713432c00189 100644
--- a/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolMasterService.java
+++ b/test/framework/src/main/java/org/opensearch/cluster/service/FakeThreadPoolMasterService.java
@@ -6,208 +6,23 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.cluster.service;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.opensearch.action.ActionListener;
-import org.opensearch.cluster.ClusterChangedEvent;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.coordination.ClusterStatePublisher.AckListener;
-import org.opensearch.common.UUIDs;
-import org.opensearch.common.settings.ClusterSettings;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.util.concurrent.PrioritizedOpenSearchThreadPoolExecutor;
-import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.node.Node;
 import org.opensearch.threadpool.ThreadPool;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.random;
-import static org.opensearch.test.OpenSearchTestCase.randomInt;
-
-public class FakeThreadPoolMasterService extends MasterService {
-    private static final Logger logger = LogManager.getLogger(FakeThreadPoolMasterService.class);
-
-    private final String name;
-    private final List<Runnable> pendingTasks = new ArrayList<>();
-    private final Consumer<Runnable> onTaskAvailableToRun;
-    private boolean scheduledNextTask = false;
-    private boolean taskInProgress = false;
-    private boolean waitForPublish = false;
-
+/**
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link FakeThreadPoolClusterManagerService}
+ */
+@Deprecated
+public class FakeThreadPoolMasterService extends FakeThreadPoolClusterManagerService {
     public FakeThreadPoolMasterService(
         String nodeName,
         String serviceName,
         ThreadPool threadPool,
         Consumer<Runnable> onTaskAvailableToRun
     ) {
-        super(
-            Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), nodeName).build(),
-            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
-            threadPool
-        );
-        this.name = serviceName;
-        this.onTaskAvailableToRun = onTaskAvailableToRun;
-    }
-
-    @Override
-    protected PrioritizedOpenSearchThreadPoolExecutor createThreadPoolExecutor() {
-        return new PrioritizedOpenSearchThreadPoolExecutor(
-            name,
-            1,
-            1,
-            1,
-            TimeUnit.SECONDS,
-            OpenSearchExecutors.daemonThreadFactory(name),
-            null,
-            null
-        ) {
-
-            @Override
-            public void execute(Runnable command, final TimeValue timeout, final Runnable timeoutCallback) {
-                execute(command);
-            }
-
-            @Override
-            public void execute(Runnable command) {
-                pendingTasks.add(command);
-                scheduleNextTaskIfNecessary();
-            }
-        };
-    }
-
-    public int getFakeMasterServicePendingTaskCount() {
-        return pendingTasks.size();
-    }
-
-    private void scheduleNextTaskIfNecessary() {
-        if (taskInProgress == false && pendingTasks.isEmpty() == false && scheduledNextTask == false) {
-            scheduledNextTask = true;
-            onTaskAvailableToRun.accept(new Runnable() {
-                @Override
-                public String toString() {
-                    return "master service scheduling next task";
-                }
-
-                @Override
-                public void run() {
-                    assert taskInProgress == false;
-                    assert waitForPublish == false;
-                    assert scheduledNextTask;
-                    final int taskIndex = randomInt(pendingTasks.size() - 1);
-                    logger.debug("next master service task: choosing task {} of {}", taskIndex, pendingTasks.size());
-                    final Runnable task = pendingTasks.remove(taskIndex);
-                    taskInProgress = true;
-                    scheduledNextTask = false;
-                    final ThreadContext threadContext = threadPool.getThreadContext();
-                    try (ThreadContext.StoredContext ignored = threadContext.stashContext()) {
-                        threadContext.markAsSystemContext();
-                        task.run();
-                    }
-                    if (waitForPublish == false) {
-                        taskInProgress = false;
-                    }
-                    FakeThreadPoolMasterService.this.scheduleNextTaskIfNecessary();
-                }
-            });
-        }
-    }
-
-    @Override
-    public ClusterState.Builder incrementVersion(ClusterState clusterState) {
-        // generate cluster UUID deterministically for repeatable tests
-        return ClusterState.builder(clusterState).incrementVersion().stateUUID(UUIDs.randomBase64UUID(random()));
-    }
-
-    @Override
-    protected void publish(ClusterChangedEvent clusterChangedEvent, TaskOutputs taskOutputs, long startTimeMillis) {
-        assert waitForPublish == false;
-        waitForPublish = true;
-        final AckListener ackListener = taskOutputs.createAckListener(threadPool, clusterChangedEvent.state());
-        final ActionListener<Void> publishListener = new ActionListener<Void>() {
-
-            private boolean listenerCalled = false;
-
-            @Override
-            public void onResponse(Void aVoid) {
-                assert listenerCalled == false;
-                listenerCalled = true;
-                assert waitForPublish;
-                waitForPublish = false;
-                try {
-                    onPublicationSuccess(clusterChangedEvent, taskOutputs);
-                } finally {
-                    taskInProgress = false;
-                    scheduleNextTaskIfNecessary();
-                }
-            }
-
-            @Override
-            public void onFailure(Exception e) {
-                assert listenerCalled == false;
-                listenerCalled = true;
-                assert waitForPublish;
-                waitForPublish = false;
-                try {
-                    onPublicationFailed(clusterChangedEvent, taskOutputs, startTimeMillis, e);
-                } finally {
-                    taskInProgress = false;
-                    scheduleNextTaskIfNecessary();
-                }
-            }
-        };
-        threadPool.generic().execute(threadPool.getThreadContext().preserveContext(new Runnable() {
-            @Override
-            public void run() {
-                clusterStatePublisher.publish(clusterChangedEvent, publishListener, wrapAckListener(ackListener));
-            }
-
-            @Override
-            public String toString() {
-                return "publish change of cluster state from version ["
-                    + clusterChangedEvent.previousState().version()
-                    + "] in term ["
-                    + clusterChangedEvent.previousState().term()
-                    + "] to version ["
-                    + clusterChangedEvent.state().version()
-                    + "] in term ["
-                    + clusterChangedEvent.state().term()
-                    + "]";
-            }
-        }));
-    }
-
-    protected AckListener wrapAckListener(AckListener ackListener) {
-        return ackListener;
+        super(nodeName, serviceName, threadPool, onTaskAvailableToRun);
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/common/breaker/TestCircuitBreaker.java b/test/framework/src/main/java/org/opensearch/common/breaker/TestCircuitBreaker.java
index bbacdd2ac4eec..9705a56700f72 100644
--- a/test/framework/src/main/java/org/opensearch/common/breaker/TestCircuitBreaker.java
+++ b/test/framework/src/main/java/org/opensearch/common/breaker/TestCircuitBreaker.java
@@ -32,6 +32,9 @@
 
 package org.opensearch.common.breaker;
 
+import org.opensearch.core.common.breaker.CircuitBreakingException;
+import org.opensearch.core.common.breaker.NoopCircuitBreaker;
+
 import java.util.concurrent.atomic.AtomicBoolean;
 
 public class TestCircuitBreaker extends NoopCircuitBreaker {
diff --git a/test/framework/src/main/java/org/opensearch/common/bytes/AbstractBytesReferenceTestCase.java b/test/framework/src/main/java/org/opensearch/common/bytes/AbstractBytesReferenceTestCase.java
index dca46c37ca7d2..855f2a7d7a6dc 100644
--- a/test/framework/src/main/java/org/opensearch/common/bytes/AbstractBytesReferenceTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/common/bytes/AbstractBytesReferenceTestCase.java
@@ -35,14 +35,17 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.BytesRefIterator;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.ReleasableBytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.util.ByteArray;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.AbstractBytesReference;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.EOFException;
@@ -478,6 +481,45 @@ public void testToUtf8() throws IOException {
         // TODO: good way to test?
     }
 
+    public void testUTF8toString_ExceedsMaxLength() {
+        AbstractBytesReference abr = new TestAbstractBytesReference();
+        IllegalArgumentException e = assertThrows(IllegalArgumentException.class, abr::utf8ToString);
+        assertTrue(e.getMessage().contains("UTF16 String size is"));
+        assertTrue(e.getMessage().contains("should be less than"));
+    }
+
+    static class TestAbstractBytesReference extends AbstractBytesReference {
+        @Override
+        public byte get(int index) {
+            return 0;
+        }
+
+        @Override
+        public int length() {
+            return 0;
+        }
+
+        @Override
+        public BytesReference slice(int from, int length) {
+            return null;
+        }
+
+        @Override
+        public long ramBytesUsed() {
+            return 0;
+        }
+
+        @Override
+        public BytesRef toBytesRef() {
+            return new BytesRef("UTF16 length exceed test");
+        }
+
+        @Override
+        public int getMaxUTF16Length() {
+            return 1;
+        }
+    }
+
     public void testToBytesRef() throws IOException {
         int length = randomIntBetween(0, PAGE_SIZE);
         BytesReference pbr = newBytesReference(length);
diff --git a/test/framework/src/main/java/org/opensearch/common/hash/AvalancheStats.java b/test/framework/src/main/java/org/opensearch/common/hash/AvalancheStats.java
new file mode 100644
index 0000000000000..c1600abcacd3e
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/common/hash/AvalancheStats.java
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import java.util.Locale;
+
+/**
+ * Represents the avalanche statistics of a hash function.
+ */
+public class AvalancheStats {
+    private final int inputBits;
+    private final int outputBits;
+    private final double bias;
+    private final double sumOfSquaredErrors;
+
+    public AvalancheStats(int[][] flips, int iterations) {
+        this.inputBits = flips.length;
+        this.outputBits = flips[0].length;
+        double sumOfBiases = 0;
+        double sumOfSquaredErrors = 0;
+
+        for (int i = 0; i < inputBits; i++) {
+            for (int o = 0; o < outputBits; o++) {
+                sumOfSquaredErrors += Math.pow(0.5 - ((double) flips[i][o] / iterations), 2);
+                sumOfBiases += 2 * ((double) flips[i][o] / iterations) - 1;
+            }
+        }
+
+        this.bias = Math.abs(sumOfBiases / (inputBits * outputBits));
+        this.sumOfSquaredErrors = sumOfSquaredErrors;
+    }
+
+    public double bias() {
+        return bias;
+    }
+
+    public double diffusion() {
+        return 1 - bias;
+    }
+
+    public double sumOfSquaredErrors() {
+        return sumOfSquaredErrors;
+    }
+
+    @Override
+    public String toString() {
+        return String.format(
+            Locale.ROOT,
+            "AvalancheStats{inputBits=%d, outputBits=%d, bias=%.4f%%, diffusion=%.4f%%, sumOfSquaredErrors=%.2f}",
+            inputBits,
+            outputBits,
+            bias() * 100,
+            diffusion() * 100,
+            sumOfSquaredErrors()
+        );
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/common/hash/HashFunctionTestCase.java b/test/framework/src/main/java/org/opensearch/common/hash/HashFunctionTestCase.java
new file mode 100644
index 0000000000000..e272fe0962047
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/common/hash/HashFunctionTestCase.java
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import org.opensearch.common.Randomness;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * Base class for testing the quality of hash functions.
+ */
+public abstract class HashFunctionTestCase extends OpenSearchTestCase {
+    private static final int[] INPUT_BITS = new int[] { 24, 32, 40, 48, 56, 64, 72, 80, 96, 112, 128, 160, 512, 1024 };
+    private static final int ITERATIONS = 1000;
+    private static final double BIAS_THRESHOLD = 0.01; // 1%
+
+    public abstract byte[] hash(byte[] input);
+
+    public abstract int outputBits();
+
+    /**
+     * Tests if the hash function shows an avalanche effect, i.e, flipping a single input bit
+     * should flip half the output bits.
+     */
+    public void testAvalanche() {
+        for (int inputBits : INPUT_BITS) {
+            AvalancheStats stats = simulate(inputBits);
+            if (stats.bias() >= BIAS_THRESHOLD) {
+                fail("bias exceeds threshold: " + stats);
+            }
+        }
+    }
+
+    private AvalancheStats simulate(int inputBits) {
+        int outputBits = outputBits();
+        assert inputBits % 8 == 0; // using full bytes for simplicity
+        assert outputBits % 8 == 0; // using full bytes for simplicity
+        byte[] input = new byte[inputBits >>> 3];
+        Random random = Randomness.get();
+        int[][] flips = new int[inputBits][outputBits];
+
+        for (int iter = 0; iter < ITERATIONS; iter++) {
+            random.nextBytes(input);
+            byte[] hash = Arrays.copyOf(hash(input), outputBits >>> 3); // copying since the underlying byte-array is reused
+
+            for (int i = 0; i < inputBits; i++) {
+                flipBit(input, i); // flip one bit
+                byte[] newHash = hash(input); // recompute the hash; half the bits should have flipped
+                flipBit(input, i); // return to original
+
+                for (int o = 0; o < outputBits; o++) {
+                    flips[i][o] += getBit(hash, o) ^ getBit(newHash, o);
+                }
+            }
+        }
+
+        return new AvalancheStats(flips, ITERATIONS);
+    }
+
+    private static void flipBit(byte[] input, int position) {
+        int offset = position / 8;
+        int bit = position & 7;
+        input[offset] ^= (1 << bit);
+    }
+
+    private static int getBit(byte[] input, int position) {
+        int offset = position / 8;
+        int bit = position & 7;
+        return (input[offset] >>> bit) & 1;
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/common/logging/JsonLogLine.java b/test/framework/src/main/java/org/opensearch/common/logging/JsonLogLine.java
index 8f26789ec61e1..d78ef238e86ee 100644
--- a/test/framework/src/main/java/org/opensearch/common/logging/JsonLogLine.java
+++ b/test/framework/src/main/java/org/opensearch/common/logging/JsonLogLine.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.common.logging;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.ObjectParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.ObjectParser;
 
 import java.util.List;
 
diff --git a/test/framework/src/main/java/org/opensearch/common/logging/JsonLogsStream.java b/test/framework/src/main/java/org/opensearch/common/logging/JsonLogsStream.java
index 606f0f30426bd..20973d9879864 100644
--- a/test/framework/src/main/java/org/opensearch/common/logging/JsonLogsStream.java
+++ b/test/framework/src/main/java/org/opensearch/common/logging/JsonLogsStream.java
@@ -32,10 +32,10 @@
 
 package org.opensearch.common.logging;
 
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.BufferedReader;
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/common/logging/TestThreadInfoPatternConverter.java b/test/framework/src/main/java/org/opensearch/common/logging/TestThreadInfoPatternConverter.java
index 2543d702e481f..dffc746870499 100644
--- a/test/framework/src/main/java/org/opensearch/common/logging/TestThreadInfoPatternConverter.java
+++ b/test/framework/src/main/java/org/opensearch/common/logging/TestThreadInfoPatternConverter.java
@@ -32,10 +32,6 @@
 
 package org.opensearch.common.logging;
 
-import java.util.Arrays;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 import org.apache.logging.log4j.core.LogEvent;
 import org.apache.logging.log4j.core.config.plugins.Plugin;
 import org.apache.logging.log4j.core.pattern.ConverterKeys;
@@ -43,6 +39,10 @@
 import org.apache.logging.log4j.core.pattern.PatternConverter;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
+import java.util.Arrays;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 /**
  * Converts {@code %test_thread_info} in log4j patterns into information
  * based on the loggin thread's name. If that thread is part of an
diff --git a/test/framework/src/main/java/org/opensearch/common/lucene/store/OpenSearchIndexInputTestCase.java b/test/framework/src/main/java/org/opensearch/common/lucene/store/OpenSearchIndexInputTestCase.java
index 4fb310b2370ed..e9d5719f04706 100644
--- a/test/framework/src/main/java/org/opensearch/common/lucene/store/OpenSearchIndexInputTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/common/lucene/store/OpenSearchIndexInputTestCase.java
@@ -32,13 +32,13 @@
 package org.opensearch.common.lucene.store;
 
 import org.apache.lucene.store.IndexInput;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.OpenSearchThreadPoolExecutor;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
diff --git a/test/framework/src/main/java/org/opensearch/common/settings/MockSecureSettings.java b/test/framework/src/main/java/org/opensearch/common/settings/MockSecureSettings.java
index 6144e89deadb3..28660563a7ab7 100644
--- a/test/framework/src/main/java/org/opensearch/common/settings/MockSecureSettings.java
+++ b/test/framework/src/main/java/org/opensearch/common/settings/MockSecureSettings.java
@@ -33,6 +33,7 @@
 package org.opensearch.common.settings;
 
 import org.opensearch.common.hash.MessageDigests;
+import org.opensearch.core.common.settings.SecureString;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/common/util/MockBigArrays.java b/test/framework/src/main/java/org/opensearch/common/util/MockBigArrays.java
index fc628ca5228e6..faf97039974ea 100644
--- a/test/framework/src/main/java/org/opensearch/common/util/MockBigArrays.java
+++ b/test/framework/src/main/java/org/opensearch/common/util/MockBigArrays.java
@@ -34,13 +34,16 @@
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
 import com.carrotsearch.randomizedtesting.SeedUtils;
+
+import org.apache.lucene.tests.util.LuceneTestCase;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.Accountables;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.tests.util.LuceneTestCase;
-import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.util.BigArray;
+import org.opensearch.core.common.util.ByteArray;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -66,21 +69,22 @@ public class MockBigArrays extends BigArrays {
     private static final ConcurrentMap<Object, Object> ACQUIRED_ARRAYS = new ConcurrentHashMap<>();
 
     public static void ensureAllArraysAreReleased() throws Exception {
-        final Map<Object, Object> masterCopy = new HashMap<>(ACQUIRED_ARRAYS);
-        if (!masterCopy.isEmpty()) {
+        final Map<Object, Object> clusterManagerCopy = new HashMap<>(ACQUIRED_ARRAYS);
+        if (!clusterManagerCopy.isEmpty()) {
             // not empty, we might be executing on a shared cluster that keeps on obtaining
-            // and releasing arrays, lets make sure that after a reasonable timeout, all master
+            // and releasing arrays, lets make sure that after a reasonable timeout, all cluster-manager
             // copy (snapshot) have been released
             try {
-                assertBusy(() -> assertTrue(Sets.haveEmptyIntersection(masterCopy.keySet(), ACQUIRED_ARRAYS.keySet())));
+                assertBusy(() -> assertTrue(Sets.haveEmptyIntersection(clusterManagerCopy.keySet(), ACQUIRED_ARRAYS.keySet())));
             } catch (AssertionError ex) {
-                masterCopy.keySet().retainAll(ACQUIRED_ARRAYS.keySet());
-                ACQUIRED_ARRAYS.keySet().removeAll(masterCopy.keySet()); // remove all existing master copy we will report on
-                if (!masterCopy.isEmpty()) {
-                    Iterator<Object> causes = masterCopy.values().iterator();
+                clusterManagerCopy.keySet().retainAll(ACQUIRED_ARRAYS.keySet());
+                // remove all existing cluster-manager copy we will report on
+                ACQUIRED_ARRAYS.keySet().removeAll(clusterManagerCopy.keySet());
+                if (!clusterManagerCopy.isEmpty()) {
+                    Iterator<Object> causes = clusterManagerCopy.values().iterator();
                     Object firstCause = causes.next();
                     RuntimeException exception = new RuntimeException(
-                        masterCopy.size() + " arrays have not been released",
+                        clusterManagerCopy.size() + " arrays have not been released",
                         firstCause instanceof Throwable ? (Throwable) firstCause : null
                     );
                     while (causes.hasNext()) {
diff --git a/test/framework/src/main/java/org/opensearch/common/util/MockPageCacheRecycler.java b/test/framework/src/main/java/org/opensearch/common/util/MockPageCacheRecycler.java
index 471cf01a3f7d2..431267c9dfb0d 100644
--- a/test/framework/src/main/java/org/opensearch/common/util/MockPageCacheRecycler.java
+++ b/test/framework/src/main/java/org/opensearch/common/util/MockPageCacheRecycler.java
@@ -53,19 +53,23 @@ public class MockPageCacheRecycler extends PageCacheRecycler {
     private static final ConcurrentMap<Object, Throwable> ACQUIRED_PAGES = new ConcurrentHashMap<>();
 
     public static void ensureAllPagesAreReleased() throws Exception {
-        final Map<Object, Throwable> masterCopy = new HashMap<>(ACQUIRED_PAGES);
-        if (!masterCopy.isEmpty()) {
+        final Map<Object, Throwable> clusterManagerCopy = new HashMap<>(ACQUIRED_PAGES);
+        if (!clusterManagerCopy.isEmpty()) {
             // not empty, we might be executing on a shared cluster that keeps on obtaining
-            // and releasing pages, lets make sure that after a reasonable timeout, all master
+            // and releasing pages, lets make sure that after a reasonable timeout, all cluster-manager
             // copy (snapshot) have been released
-            final boolean success = waitUntil(() -> Sets.haveEmptyIntersection(masterCopy.keySet(), ACQUIRED_PAGES.keySet()));
+            final boolean success = waitUntil(() -> Sets.haveEmptyIntersection(clusterManagerCopy.keySet(), ACQUIRED_PAGES.keySet()));
             if (!success) {
-                masterCopy.keySet().retainAll(ACQUIRED_PAGES.keySet());
-                ACQUIRED_PAGES.keySet().removeAll(masterCopy.keySet()); // remove all existing master copy we will report on
-                if (!masterCopy.isEmpty()) {
-                    Iterator<Throwable> causes = masterCopy.values().iterator();
+                clusterManagerCopy.keySet().retainAll(ACQUIRED_PAGES.keySet());
+                // remove all existing cluster-manager copy we will report on
+                ACQUIRED_PAGES.keySet().removeAll(clusterManagerCopy.keySet());
+                if (!clusterManagerCopy.isEmpty()) {
+                    Iterator<Throwable> causes = clusterManagerCopy.values().iterator();
                     Throwable firstCause = causes.next();
-                    RuntimeException exception = new RuntimeException(masterCopy.size() + " pages have not been released", firstCause);
+                    RuntimeException exception = new RuntimeException(
+                        clusterManagerCopy.size() + " pages have not been released",
+                        firstCause
+                    );
                     while (causes.hasNext()) {
                         exception.addSuppressed(causes.next());
                     }
diff --git a/test/framework/src/main/java/org/opensearch/gateway/MockGatewayMetaState.java b/test/framework/src/main/java/org/opensearch/gateway/MockGatewayMetaState.java
index da67b63e11687..d77596cf5cdd1 100644
--- a/test/framework/src/main/java/org/opensearch/gateway/MockGatewayMetaState.java
+++ b/test/framework/src/main/java/org/opensearch/gateway/MockGatewayMetaState.java
@@ -33,6 +33,7 @@
 package org.opensearch.gateway;
 
 import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
 import org.opensearch.cluster.metadata.Manifest;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.MetadataIndexUpgradeService;
@@ -42,8 +43,10 @@
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.NodeEnvironment;
+import org.opensearch.gateway.remote.RemoteClusterStateService;
+import org.opensearch.index.recovery.RemoteStoreRestoreService;
 import org.opensearch.plugins.MetadataUpgrader;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
@@ -62,10 +65,26 @@
 public class MockGatewayMetaState extends GatewayMetaState {
     private final DiscoveryNode localNode;
     private final BigArrays bigArrays;
+    private final RemoteClusterStateService remoteClusterStateService;
+    private final RemoteStoreRestoreService remoteStoreRestoreService;
 
     public MockGatewayMetaState(DiscoveryNode localNode, BigArrays bigArrays) {
         this.localNode = localNode;
         this.bigArrays = bigArrays;
+        this.remoteClusterStateService = mock(RemoteClusterStateService.class);
+        this.remoteStoreRestoreService = mock(RemoteStoreRestoreService.class);
+    }
+
+    public MockGatewayMetaState(
+        DiscoveryNode localNode,
+        BigArrays bigArrays,
+        RemoteClusterStateService remoteClusterStateService,
+        RemoteStoreRestoreService remoteStoreRestoreService
+    ) {
+        this.localNode = localNode;
+        this.bigArrays = bigArrays;
+        this.remoteClusterStateService = remoteClusterStateService;
+        this.remoteStoreRestoreService = remoteStoreRestoreService;
     }
 
     @Override
@@ -84,7 +103,17 @@ ClusterState prepareInitialClusterState(TransportService transportService, Clust
         return ClusterStateUpdaters.setLocalNode(clusterState, localNode);
     }
 
-    public void start(Settings settings, NodeEnvironment nodeEnvironment, NamedXContentRegistry xContentRegistry) {
+    @Override
+    public void close() throws IOException {
+        super.close();
+    }
+
+    public void start(
+        Settings settings,
+        NodeEnvironment nodeEnvironment,
+        NamedXContentRegistry xContentRegistry,
+        PersistedStateRegistry persistedStateRegistry
+    ) {
         final TransportService transportService = mock(TransportService.class);
         when(transportService.getThreadPool()).thenReturn(mock(ThreadPool.class));
         final ClusterService clusterService = mock(ClusterService.class);
@@ -110,7 +139,10 @@ public void start(Settings settings, NodeEnvironment nodeEnvironment, NamedXCont
                 bigArrays,
                 new ClusterSettings(settings, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
                 () -> 0L
-            )
+            ),
+            remoteClusterStateService,
+            persistedStateRegistry,
+            remoteStoreRestoreService
         );
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/index/MapperTestUtils.java b/test/framework/src/main/java/org/opensearch/index/MapperTestUtils.java
index b01b4ee20c421..108492c1cf8f9 100644
--- a/test/framework/src/main/java/org/opensearch/index/MapperTestUtils.java
+++ b/test/framework/src/main/java/org/opensearch/index/MapperTestUtils.java
@@ -36,7 +36,7 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.mapper.DocumentMapper;
@@ -52,10 +52,10 @@
 import java.nio.file.Path;
 import java.util.Collections;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.expectThrows;
 import static org.opensearch.test.OpenSearchTestCase.createTestAnalysis;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
+import static org.apache.lucene.tests.util.LuceneTestCase.expectThrows;
 
 public class MapperTestUtils {
 
diff --git a/test/framework/src/main/java/org/opensearch/index/MockEngineFactoryPlugin.java b/test/framework/src/main/java/org/opensearch/index/MockEngineFactoryPlugin.java
index 7d3282ca4443a..72d34676850b9 100644
--- a/test/framework/src/main/java/org/opensearch/index/MockEngineFactoryPlugin.java
+++ b/test/framework/src/main/java/org/opensearch/index/MockEngineFactoryPlugin.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index;
 
-import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
+import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.index.engine.EngineFactory;
 import org.opensearch.plugins.EnginePlugin;
diff --git a/test/framework/src/main/java/org/opensearch/index/RandomCreateIndexGenerator.java b/test/framework/src/main/java/org/opensearch/index/RandomCreateIndexGenerator.java
index 1498a0b7b2d17..f016d9450425d 100644
--- a/test/framework/src/main/java/org/opensearch/index/RandomCreateIndexGenerator.java
+++ b/test/framework/src/main/java/org/opensearch/index/RandomCreateIndexGenerator.java
@@ -35,11 +35,13 @@
 import org.opensearch.action.admin.indices.alias.Alias;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
@@ -96,7 +98,7 @@ public static Settings randomIndexSettings() {
      * Creates a random mapping
      */
     public static XContentBuilder randomMapping() throws IOException {
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         builder.startObject();
 
         randomMappingFields(builder, true);
@@ -112,8 +114,12 @@ public static void randomMappingFields(XContentBuilder builder, boolean allowObj
         builder.startObject("properties");
 
         int fieldsNo = randomIntBetween(0, 5);
-        for (int i = 0; i < fieldsNo; i++) {
-            builder.startObject(randomAlphaOfLength(5));
+        Set<String> uniqueFields = new HashSet<>();
+        while (uniqueFields.size() < fieldsNo) {
+            uniqueFields.add(randomAlphaOfLength(5));
+        }
+        for (String uniqueField : uniqueFields) {
+            builder.startObject(uniqueField);
 
             if (allowObjectField && randomBoolean()) {
                 randomMappingFields(builder, false);
diff --git a/test/framework/src/main/java/org/opensearch/index/analysis/AnalysisTestsHelper.java b/test/framework/src/main/java/org/opensearch/index/analysis/AnalysisTestsHelper.java
index ae542819d157e..80c54ec20d51f 100644
--- a/test/framework/src/main/java/org/opensearch/index/analysis/AnalysisTestsHelper.java
+++ b/test/framework/src/main/java/org/opensearch/index/analysis/AnalysisTestsHelper.java
@@ -39,8 +39,8 @@
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.plugins.AnalysisPlugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.IndexSettingsModule;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.file.Path;
diff --git a/test/framework/src/main/java/org/opensearch/index/engine/EngineTestCase.java b/test/framework/src/main/java/org/opensearch/index/engine/EngineTestCase.java
index 2bce5a7c81794..d898c81159087 100644
--- a/test/framework/src/main/java/org/opensearch/index/engine/EngineTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/engine/EngineTestCase.java
@@ -49,6 +49,7 @@
 import org.apache.lucene.index.LiveIndexWriterConfig;
 import org.apache.lucene.index.MergePolicy;
 import org.apache.lucene.index.NumericDocValues;
+import org.apache.lucene.index.StoredFields;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexSearcher;
@@ -61,8 +62,6 @@
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
-import org.junit.After;
-import org.junit.Before;
 import org.opensearch.Version;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.replication.ReplicationResponse;
@@ -72,9 +71,6 @@
 import org.opensearch.common.CheckedBiFunction;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.lucene.Lucene;
@@ -82,13 +78,18 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MapperTestUtils;
 import org.opensearch.index.VersionType;
@@ -109,17 +110,21 @@
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeases;
 import org.opensearch.index.seqno.SequenceNumbers;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.translog.InternalTranslogManager;
+import org.opensearch.index.translog.LocalTranslog;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.index.translog.TranslogConfig;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.index.translog.TranslogDeletionPolicy;
+import org.opensearch.index.translog.TranslogManager;
+import org.opensearch.index.translog.listener.TranslogEventListener;
 import org.opensearch.test.DummyShardLock;
 import org.opensearch.test.IndexSettingsModule;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.junit.After;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.nio.charset.Charset;
@@ -144,14 +149,15 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.shuffle;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.greaterThanOrEqualTo;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
-import static org.hamcrest.Matchers.notNullValue;
 import static org.opensearch.index.engine.Engine.Operation.Origin.PEER_RECOVERY;
 import static org.opensearch.index.engine.Engine.Operation.Origin.PRIMARY;
 import static org.opensearch.index.engine.Engine.Operation.Origin.REPLICA;
 import static org.opensearch.index.translog.TranslogDeletionPolicies.createTranslogDeletionPolicy;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.hamcrest.Matchers.notNullValue;
 
 public abstract class EngineTestCase extends OpenSearchTestCase {
 
@@ -205,7 +211,7 @@ protected Settings indexSettings() {
     public void setUp() throws Exception {
         super.setUp();
         primaryTerm.set(randomLongBetween(1, Long.MAX_VALUE));
-        CodecService codecService = new CodecService(null, logger);
+        CodecService codecService = new CodecService(null, INDEX_SETTINGS, logger);
         String name = Codec.getDefault().getName();
         if (Arrays.asList(codecService.availableCodecs()).contains(name)) {
             // some codecs are read only so we only take the ones that we have in the service and randomly
@@ -221,7 +227,6 @@ public void setUp() throws Exception {
         Lucene.cleanLuceneIndex(store.directory());
         Lucene.cleanLuceneIndex(storeReplica.directory());
         primaryTranslogDir = createTempDir("translog-primary");
-        translogHandler = createTranslogHandler(defaultSettings);
         engine = createEngine(store, primaryTranslogDir);
         LiveIndexWriterConfig currentIndexWriterConfig = engine.getCurrentIndexWriterConfig();
 
@@ -242,84 +247,81 @@ public void setUp() throws Exception {
     }
 
     public EngineConfig copy(EngineConfig config, LongSupplier globalCheckpointSupplier) {
-        return new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            config.getIndexSettings(),
-            config.getWarmer(),
-            config.getStore(),
-            config.getMergePolicy(),
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            config.getTranslogConfig(),
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            Collections.emptyList(),
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            globalCheckpointSupplier,
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            tombstoneDocSupplier()
-        );
+        return new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(config.getIndexSettings())
+            .warmer(config.getWarmer())
+            .store(config.getStore())
+            .mergePolicy(config.getMergePolicy())
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(config.getTranslogConfig())
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(emptyList())
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(globalCheckpointSupplier)
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(tombstoneDocSupplier())
+            .build();
     }
 
     public EngineConfig copy(EngineConfig config, Analyzer analyzer) {
-        return new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            config.getIndexSettings(),
-            config.getWarmer(),
-            config.getStore(),
-            config.getMergePolicy(),
-            analyzer,
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            config.getTranslogConfig(),
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            Collections.emptyList(),
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            config.getGlobalCheckpointSupplier(),
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            config.getTombstoneDocSupplier()
-        );
+        return new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(config.getIndexSettings())
+            .warmer(config.getWarmer())
+            .store(config.getStore())
+            .mergePolicy(config.getMergePolicy())
+            .analyzer(analyzer)
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(config.getTranslogConfig())
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(emptyList())
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+            .build();
     }
 
     public EngineConfig copy(EngineConfig config, MergePolicy mergePolicy) {
-        return new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            config.getIndexSettings(),
-            config.getWarmer(),
-            config.getStore(),
-            mergePolicy,
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            config.getTranslogConfig(),
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            Collections.emptyList(),
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            config.getGlobalCheckpointSupplier(),
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            config.getTombstoneDocSupplier()
-        );
+        return new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(config.getIndexSettings())
+            .warmer(config.getWarmer())
+            .store(config.getStore())
+            .mergePolicy(mergePolicy)
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, config.getIndexSettings(), logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(config.getTranslogConfig())
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(emptyList())
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(config.getTombstoneDocSupplier())
+            .build();
     }
 
     @Override
@@ -328,24 +330,36 @@ public void tearDown() throws Exception {
         super.tearDown();
         try {
             if (engine != null && engine.isClosed.get() == false) {
-                engine.getTranslog().getDeletionPolicy().assertNoOpenTranslogRefs();
-                assertConsistentHistoryBetweenTranslogAndLuceneIndex(engine);
-                assertNoInFlightDocuments(engine);
-                assertMaxSeqNoInCommitUserData(engine);
-                assertAtMostOneLuceneDocumentPerSequenceNumber(engine);
+                engine.ensureOpen();
+                assertEngineCleanedUp(engine, assertAndGetInternalTranslogManager(engine.translogManager()).getDeletionPolicy());
             }
             if (replicaEngine != null && replicaEngine.isClosed.get() == false) {
-                replicaEngine.getTranslog().getDeletionPolicy().assertNoOpenTranslogRefs();
-                assertConsistentHistoryBetweenTranslogAndLuceneIndex(replicaEngine);
-                assertNoInFlightDocuments(replicaEngine);
-                assertMaxSeqNoInCommitUserData(replicaEngine);
-                assertAtMostOneLuceneDocumentPerSequenceNumber(replicaEngine);
+                replicaEngine.ensureOpen();
+                assertEngineCleanedUp(
+                    replicaEngine,
+                    assertAndGetInternalTranslogManager(replicaEngine.translogManager()).getDeletionPolicy()
+                );
             }
         } finally {
             IOUtils.close(replicaEngine, storeReplica, engine, store, () -> terminate(threadPool));
         }
     }
 
+    protected InternalTranslogManager assertAndGetInternalTranslogManager(final TranslogManager translogManager) {
+        assertThat(translogManager, instanceOf(InternalTranslogManager.class));
+        return (InternalTranslogManager) translogManager;
+    }
+
+    protected void assertEngineCleanedUp(Engine engine, TranslogDeletionPolicy translogDeletionPolicy) throws Exception {
+        if (engine.isClosed.get() == false) {
+            translogDeletionPolicy.assertNoOpenTranslogRefs();
+            assertConsistentHistoryBetweenTranslogAndLuceneIndex(engine);
+            assertNoInFlightDocuments(engine);
+            assertMaxSeqNoInCommitUserData(engine);
+            assertAtMostOneLuceneDocumentPerSequenceNumber(engine);
+        }
+    }
+
     protected static ParseContext.Document testDocumentWithTextField() {
         return testDocumentWithTextField("test");
     }
@@ -408,23 +422,22 @@ protected static ParsedDocument testParsedDocument(
         } else {
             document.add(new StoredField(SourceFieldMapper.NAME, ref.bytes, ref.offset, ref.length));
         }
-        return new ParsedDocument(versionField, seqID, id, routing, Arrays.asList(document), source, XContentType.JSON, mappingUpdate);
+        return new ParsedDocument(versionField, seqID, id, routing, Arrays.asList(document), source, MediaTypeRegistry.JSON, mappingUpdate);
     }
 
     public static CheckedBiFunction<String, Integer, ParsedDocument, IOException> nestedParsedDocFactory() throws Exception {
         final MapperService mapperService = createMapperService();
-        final String nestedMapping = Strings.toString(
-            XContentFactory.jsonBuilder()
-                .startObject()
-                .startObject("type")
-                .startObject("properties")
-                .startObject("nested_field")
-                .field("type", "nested")
-                .endObject()
-                .endObject()
-                .endObject()
-                .endObject()
-        );
+        final String nestedMapping = XContentFactory.jsonBuilder()
+            .startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("nested_field")
+            .field("type", "nested")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .toString();
         final DocumentMapper nestedMapper = mapperService.documentMapperParser().parse("type", new CompressedXContent(nestedMapping));
         return (docId, nestedFieldValues) -> {
             final XContentBuilder source = XContentFactory.jsonBuilder().startObject().field("field", "value");
@@ -436,7 +449,7 @@ public static CheckedBiFunction<String, Integer, ParsedDocument, IOException> ne
                 source.endObject();
             }
             source.endObject();
-            return nestedMapper.parse(new SourceToParse("test", docId, BytesReference.bytes(source), XContentType.JSON));
+            return nestedMapper.parse(new SourceToParse("test", docId, BytesReference.bytes(source), MediaTypeRegistry.JSON));
         };
     }
 
@@ -465,7 +478,7 @@ public ParsedDocument newDeleteTombstoneDoc(String id) {
                     null,
                     Collections.singletonList(doc),
                     new BytesArray("{}"),
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     null
                 );
             }
@@ -483,7 +496,16 @@ public ParsedDocument newNoopTombstoneDoc(String reason) {
                 doc.add(versionField);
                 BytesRef byteRef = new BytesRef(reason);
                 doc.add(new StoredField(SourceFieldMapper.NAME, byteRef.bytes, byteRef.offset, byteRef.length));
-                return new ParsedDocument(versionField, seqID, null, null, Collections.singletonList(doc), null, XContentType.JSON, null);
+                return new ParsedDocument(
+                    versionField,
+                    seqID,
+                    null,
+                    null,
+                    Collections.singletonList(doc),
+                    null,
+                    MediaTypeRegistry.JSON,
+                    null
+                );
             }
         };
     }
@@ -505,14 +527,14 @@ protected Translog createTranslog(LongSupplier primaryTermSupplier) throws IOExc
     }
 
     protected Translog createTranslog(Path translogPath, LongSupplier primaryTermSupplier) throws IOException {
-        TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE);
+        TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, INDEX_SETTINGS, BigArrays.NON_RECYCLING_INSTANCE, "");
         String translogUUID = Translog.createEmptyTranslog(
             translogPath,
             SequenceNumbers.NO_OPS_PERFORMED,
             shardId,
             primaryTermSupplier.getAsLong()
         );
-        return new Translog(
+        return new LocalTranslog(
             translogConfig,
             translogUUID,
             createTranslogDeletionPolicy(INDEX_SETTINGS),
@@ -522,8 +544,8 @@ protected Translog createTranslog(Path translogPath, LongSupplier primaryTermSup
         );
     }
 
-    protected TranslogHandler createTranslogHandler(IndexSettings indexSettings) {
-        return new TranslogHandler(xContentRegistry(), indexSettings);
+    protected TranslogHandler createTranslogHandler(IndexSettings indexSettings, Engine engine) {
+        return new TranslogHandler(xContentRegistry(), indexSettings, engine);
     }
 
     protected InternalEngine createEngine(Store store, Path translogPath) throws IOException {
@@ -660,12 +682,13 @@ protected InternalEngine createEngine(
 
         }
         InternalEngine internalEngine = createInternalEngine(indexWriterFactory, localCheckpointTrackerSupplier, seqNoForOperation, config);
-        internalEngine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);
+        translogHandler = createTranslogHandler(config.getIndexSettings(), internalEngine);
+        internalEngine.translogManager().recoverFromTranslog(translogHandler, internalEngine.getProcessedLocalCheckpoint(), Long.MAX_VALUE);
         return internalEngine;
     }
 
     public static InternalEngine createEngine(EngineConfig engineConfig, int maxDocs) {
-        return new InternalEngine(engineConfig, maxDocs, LocalCheckpointTracker::new);
+        return new InternalEngine(engineConfig, maxDocs, LocalCheckpointTracker::new, TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER);
     }
 
     @FunctionalInterface
@@ -817,10 +840,45 @@ public EngineConfig config(
         final @Nullable Supplier<RetentionLeases> maybeRetentionLeasesSupplier,
         final CircuitBreakerService breakerService
     ) {
-        final IndexWriterConfig iwc = newIndexWriterConfig();
-        final TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, indexSettings, BigArrays.NON_RECYCLING_INSTANCE);
         final Engine.EventListener eventListener = new Engine.EventListener() {
         }; // we don't need to notify anybody in this test
+
+        return config(
+            indexSettings,
+            store,
+            translogPath,
+            mergePolicy,
+            externalRefreshListener,
+            internalRefreshListener,
+            indexSort,
+            maybeGlobalCheckpointSupplier,
+            maybeGlobalCheckpointSupplier == null ? null : () -> RetentionLeases.EMPTY,
+            breakerService,
+            eventListener
+        );
+    }
+
+    public EngineConfig config(
+        final IndexSettings indexSettings,
+        final Store store,
+        final Path translogPath,
+        final MergePolicy mergePolicy,
+        final ReferenceManager.RefreshListener externalRefreshListener,
+        final ReferenceManager.RefreshListener internalRefreshListener,
+        final Sort indexSort,
+        final @Nullable LongSupplier maybeGlobalCheckpointSupplier,
+        final @Nullable Supplier<RetentionLeases> maybeRetentionLeasesSupplier,
+        final CircuitBreakerService breakerService,
+        final Engine.EventListener eventListener
+    ) {
+        final IndexWriterConfig iwc = newIndexWriterConfig();
+        final TranslogConfig translogConfig = new TranslogConfig(
+            shardId,
+            translogPath,
+            indexSettings,
+            BigArrays.NON_RECYCLING_INSTANCE,
+            ""
+        );
         final List<ReferenceManager.RefreshListener> extRefreshListenerList = externalRefreshListener == null
             ? emptyList()
             : Collections.singletonList(externalRefreshListener);
@@ -849,30 +907,29 @@ public EngineConfig config(
             globalCheckpointSupplier = maybeGlobalCheckpointSupplier;
             retentionLeasesSupplier = maybeRetentionLeasesSupplier;
         }
-        return new EngineConfig(
-            shardId,
-            threadPool,
-            indexSettings,
-            null,
-            store,
-            mergePolicy,
-            iwc.getAnalyzer(),
-            iwc.getSimilarity(),
-            new CodecService(null, logger),
-            eventListener,
-            IndexSearcher.getDefaultQueryCache(),
-            IndexSearcher.getDefaultQueryCachingPolicy(),
-            translogConfig,
-            TimeValue.timeValueMinutes(5),
-            extRefreshListenerList,
-            intRefreshListenerList,
-            indexSort,
-            breakerService,
-            globalCheckpointSupplier,
-            retentionLeasesSupplier,
-            primaryTerm,
-            tombstoneDocSupplier()
-        );
+        return new EngineConfig.Builder().shardId(shardId)
+            .threadPool(threadPool)
+            .indexSettings(indexSettings)
+            .warmer(null)
+            .store(store)
+            .mergePolicy(mergePolicy)
+            .analyzer(iwc.getAnalyzer())
+            .similarity(iwc.getSimilarity())
+            .codecService(new CodecService(null, indexSettings, logger))
+            .eventListener(eventListener)
+            .queryCache(IndexSearcher.getDefaultQueryCache())
+            .queryCachingPolicy(IndexSearcher.getDefaultQueryCachingPolicy())
+            .translogConfig(translogConfig)
+            .flushMergesAfter(TimeValue.timeValueMinutes(5))
+            .externalRefreshListener(extRefreshListenerList)
+            .internalRefreshListener(intRefreshListenerList)
+            .indexSort(indexSort)
+            .circuitBreakerService(breakerService)
+            .globalCheckpointSupplier(globalCheckpointSupplier)
+            .retentionLeasesSupplier(retentionLeasesSupplier)
+            .primaryTermSupplier(primaryTerm)
+            .tombstoneDocSupplier(tombstoneDocSupplier())
+            .build();
     }
 
     protected EngineConfig config(
@@ -888,31 +945,30 @@ protected EngineConfig config(
                 .put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true)
                 .build()
         );
-        TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, indexSettings, BigArrays.NON_RECYCLING_INSTANCE);
-        return new EngineConfig(
-            config.getShardId(),
-            config.getThreadPool(),
-            indexSettings,
-            config.getWarmer(),
-            store,
-            config.getMergePolicy(),
-            config.getAnalyzer(),
-            config.getSimilarity(),
-            new CodecService(null, logger),
-            config.getEventListener(),
-            config.getQueryCache(),
-            config.getQueryCachingPolicy(),
-            translogConfig,
-            config.getFlushMergesAfter(),
-            config.getExternalRefreshListener(),
-            config.getInternalRefreshListener(),
-            config.getIndexSort(),
-            config.getCircuitBreakerService(),
-            config.getGlobalCheckpointSupplier(),
-            config.retentionLeasesSupplier(),
-            config.getPrimaryTermSupplier(),
-            tombstoneDocSupplier
-        );
+        TranslogConfig translogConfig = new TranslogConfig(shardId, translogPath, indexSettings, BigArrays.NON_RECYCLING_INSTANCE, "");
+        return new EngineConfig.Builder().shardId(config.getShardId())
+            .threadPool(config.getThreadPool())
+            .indexSettings(indexSettings)
+            .warmer(config.getWarmer())
+            .store(store)
+            .mergePolicy(config.getMergePolicy())
+            .analyzer(config.getAnalyzer())
+            .similarity(config.getSimilarity())
+            .codecService(new CodecService(null, indexSettings, logger))
+            .eventListener(config.getEventListener())
+            .queryCache(config.getQueryCache())
+            .queryCachingPolicy(config.getQueryCachingPolicy())
+            .translogConfig(translogConfig)
+            .flushMergesAfter(config.getFlushMergesAfter())
+            .externalRefreshListener(config.getExternalRefreshListener())
+            .internalRefreshListener(config.getInternalRefreshListener())
+            .indexSort(config.getIndexSort())
+            .circuitBreakerService(config.getCircuitBreakerService())
+            .globalCheckpointSupplier(config.getGlobalCheckpointSupplier())
+            .retentionLeasesSupplier(config.retentionLeasesSupplier())
+            .primaryTermSupplier(config.getPrimaryTermSupplier())
+            .tombstoneDocSupplier(tombstoneDocSupplier)
+            .build();
     }
 
     protected EngineConfig noOpConfig(IndexSettings indexSettings, Store store, Path translogPath) {
@@ -1274,6 +1330,7 @@ public static List<DocIdSeqNoAndSource> getDocIds(Engine engine, boolean refresh
                 NumericDocValues primaryTermDocValues = reader.getNumericDocValues(SeqNoFieldMapper.PRIMARY_TERM_NAME);
                 NumericDocValues versionDocValues = reader.getNumericDocValues(VersionFieldMapper.NAME);
                 Bits liveDocs = reader.getLiveDocs();
+                StoredFields storedFields = reader.storedFields();
                 for (int i = 0; i < reader.maxDoc(); i++) {
                     if (liveDocs == null || liveDocs.get(i)) {
                         if (primaryTermDocValues.advanceExact(i) == false) {
@@ -1281,7 +1338,7 @@ public static List<DocIdSeqNoAndSource> getDocIds(Engine engine, boolean refresh
                             continue;
                         }
                         final long primaryTerm = primaryTermDocValues.longValue();
-                        Document doc = reader.document(i, Sets.newHashSet(IdFieldMapper.NAME, SourceFieldMapper.NAME));
+                        Document doc = storedFields.document(i, Sets.newHashSet(IdFieldMapper.NAME, SourceFieldMapper.NAME));
                         BytesRef binaryID = doc.getBinaryValue(IdFieldMapper.NAME);
                         String id = Uid.decodeId(Arrays.copyOfRange(binaryID.bytes, binaryID.offset, binaryID.offset + binaryID.length));
                         final BytesRef source = doc.getBinaryValue(SourceFieldMapper.NAME);
@@ -1435,6 +1492,7 @@ public static void assertAtMostOneLuceneDocumentPerSequenceNumber(IndexSettings
         for (LeafReaderContext leaf : wrappedReader.leaves()) {
             NumericDocValues primaryTermDocValues = leaf.reader().getNumericDocValues(SeqNoFieldMapper.PRIMARY_TERM_NAME);
             NumericDocValues seqNoDocValues = leaf.reader().getNumericDocValues(SeqNoFieldMapper.NAME);
+            final StoredFields storedFields = leaf.reader().storedFields();
             int docId;
             while ((docId = seqNoDocValues.nextDoc()) != DocIdSetIterator.NO_MORE_DOCS) {
                 assertTrue(seqNoDocValues.advanceExact(docId));
@@ -1443,7 +1501,7 @@ public static void assertAtMostOneLuceneDocumentPerSequenceNumber(IndexSettings
                 if (primaryTermDocValues.advanceExact(docId)) {
                     if (seqNos.add(seqNo) == false) {
                         final IdOnlyFieldVisitor idFieldVisitor = new IdOnlyFieldVisitor();
-                        leaf.reader().document(docId, idFieldVisitor);
+                        storedFields.document(docId, idFieldVisitor);
                         throw new AssertionError("found multiple documents for seq=" + seqNo + " id=" + idFieldVisitor.getId());
                     }
                 }
@@ -1475,9 +1533,18 @@ public static MapperService createMapperService() throws IOException {
      * Exposes a translog associated with the given engine for testing purpose.
      */
     public static Translog getTranslog(Engine engine) {
-        assert engine instanceof InternalEngine : "only InternalEngines have translogs, got: " + engine.getClass();
+        // This is a hack for bwc with 2.x, main will use TranslogManager on Engine directly
+        if (engine instanceof NRTReplicationEngine) {
+            return ((NRTReplicationEngine) (engine)).getTranslog();
+        }
+        assert engine instanceof InternalEngine : "only InternalEngines or NRTReplicationEngines have translogs, got: " + engine.getClass();
         InternalEngine internalEngine = (InternalEngine) engine;
-        return internalEngine.getTranslog();
+        internalEngine.ensureOpen();
+        TranslogManager translogManager = internalEngine.translogManager();
+        assert translogManager instanceof InternalTranslogManager : "only InternalTranslogManager have translogs, got: "
+            + engine.getClass();
+        InternalTranslogManager internalTranslogManager = (InternalTranslogManager) translogManager;
+        return internalTranslogManager.getTranslog();
     }
 
     /**
diff --git a/test/framework/src/main/java/org/opensearch/index/engine/InternalTestEngine.java b/test/framework/src/main/java/org/opensearch/index/engine/InternalTestEngine.java
index 2c22c391ea3a3..20767c3b029ae 100644
--- a/test/framework/src/main/java/org/opensearch/index/engine/InternalTestEngine.java
+++ b/test/framework/src/main/java/org/opensearch/index/engine/InternalTestEngine.java
@@ -35,6 +35,7 @@
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.index.seqno.LocalCheckpointTracker;
 import org.opensearch.index.seqno.SequenceNumbers;
+import org.opensearch.index.translog.listener.TranslogEventListener;
 
 import java.io.IOException;
 import java.util.Map;
@@ -55,7 +56,7 @@ class InternalTestEngine extends InternalEngine {
         int maxDocs,
         BiFunction<Long, Long, LocalCheckpointTracker> localCheckpointTrackerSupplier
     ) {
-        super(engineConfig, maxDocs, localCheckpointTrackerSupplier);
+        super(engineConfig, maxDocs, localCheckpointTrackerSupplier, TranslogEventListener.NOOP_TRANSLOG_EVENT_LISTENER);
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/opensearch/index/engine/TranslogHandler.java b/test/framework/src/main/java/org/opensearch/index/engine/TranslogHandler.java
index e1f2357aa2400..09118fedc73e3 100644
--- a/test/framework/src/main/java/org/opensearch/index/engine/TranslogHandler.java
+++ b/test/framework/src/main/java/org/opensearch/index/engine/TranslogHandler.java
@@ -33,8 +33,8 @@
 package org.opensearch.index.engine;
 
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.VersionType;
 import org.opensearch.index.analysis.AnalysisRegistry;
@@ -50,6 +50,7 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.index.translog.TranslogRecoveryRunner;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.mapper.MapperRegistry;
 
@@ -61,17 +62,20 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 
-public class TranslogHandler implements Engine.TranslogRecoveryRunner {
+public class TranslogHandler implements TranslogRecoveryRunner {
 
     private final MapperService mapperService;
 
     private final AtomicLong appliedOperations = new AtomicLong();
 
+    private final Engine engine;
+
     long appliedOperations() {
         return appliedOperations.get();
     }
 
-    public TranslogHandler(NamedXContentRegistry xContentRegistry, IndexSettings indexSettings) {
+    public TranslogHandler(NamedXContentRegistry xContentRegistry, IndexSettings indexSettings, Engine engine) {
+        this.engine = engine;
         Map<String, NamedAnalyzer> analyzers = new HashMap<>();
         analyzers.put(AnalysisRegistry.DEFAULT_ANALYZER_NAME, new NamedAnalyzer("default", AnalyzerScope.INDEX, new StandardAnalyzer()));
         IndexAnalyzers indexAnalyzers = new IndexAnalyzers(analyzers, emptyMap(), emptyMap());
@@ -112,7 +116,7 @@ private void applyOperation(Engine engine, Engine.Operation operation) throws IO
     }
 
     @Override
-    public int run(Engine engine, Translog.Snapshot snapshot) throws IOException {
+    public int run(Translog.Snapshot snapshot) throws IOException {
         int opsRecovered = 0;
         Translog.Operation operation;
         while ((operation = snapshot.next()) != null) {
@@ -133,7 +137,13 @@ public Engine.Operation convertToEngineOp(Translog.Operation operation, Engine.O
                 final String indexName = mapperService.index().getName();
                 final Engine.Index engineIndex = IndexShard.prepareIndex(
                     docMapper(MapperService.SINGLE_MAPPING_NAME),
-                    new SourceToParse(indexName, index.id(), index.source(), XContentHelper.xContentType(index.source()), index.routing()),
+                    new SourceToParse(
+                        indexName,
+                        index.id(),
+                        index.source(),
+                        MediaTypeRegistry.xContentType(index.source()),
+                        index.routing()
+                    ),
                     index.seqNo(),
                     index.primaryTerm(),
                     index.version(),
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase.java b/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase.java
index 9103f7a45b4fc..83bb2f1ee7d65 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase.java
@@ -36,12 +36,11 @@
 import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.opensearch.Version;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
@@ -260,6 +259,6 @@ private String mappingsToString(ToXContent builder, boolean includeDefaults) thr
         x.startObject().startObject("properties");
         builder.toXContent(x, params);
         x.endObject().endObject();
-        return Strings.toString(x);
+        return x.toString();
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase2.java b/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase2.java
index d37dc45969ef4..1987a49431bf9 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase2.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/FieldMapperTestCase2.java
@@ -35,9 +35,8 @@
 import org.apache.lucene.analysis.core.KeywordAnalyzer;
 import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.NamedAnalyzer;
 
@@ -233,8 +232,8 @@ protected void assertSerializes(T builder) throws IOException {
         XContentBuilder reparsed = mappingsToJson(rebuilt, false);
         XContentBuilder reparsedWithDefault = mappingsToJson(rebuilt, true);
 
-        assertThat(Strings.toString(reparsed), equalTo(Strings.toString(mappings)));
-        assertThat(Strings.toString(reparsedWithDefault), equalTo(Strings.toString(mappingsWithDefault)));
+        assertThat(reparsed.toString(), equalTo(mappings.toString()));
+        assertThat(reparsedWithDefault.toString(), equalTo(mappingsWithDefault.toString()));
     }
 
     private XContentBuilder mappingsToJson(ToXContent builder, boolean includeDefaults) throws IOException {
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/FieldTypeTestCase.java b/test/framework/src/main/java/org/opensearch/index/mapper/FieldTypeTestCase.java
index 571f1b21dd7e3..7ed0da8509fab 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/FieldTypeTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/FieldTypeTestCase.java
@@ -38,6 +38,7 @@
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -65,7 +66,7 @@ public static List<?> fetchSourceValue(MappedFieldType fieldType, Object sourceV
     public static List<?> fetchSourceValue(MappedFieldType fieldType, Object sourceValue, String format) throws IOException {
         String field = fieldType.name();
         QueryShardContext context = mock(QueryShardContext.class);
-        when(context.sourcePath(field)).thenReturn(org.opensearch.common.collect.Set.of(field));
+        when(context.sourcePath(field)).thenReturn(Set.of(field));
 
         ValueFetcher fetcher = fieldType.valueFetcher(context, null, format);
         SourceLookup lookup = new SourceLookup();
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/MapperServiceTestCase.java b/test/framework/src/main/java/org/opensearch/index/mapper/MapperServiceTestCase.java
index db6c53bd0aa77..94c2e4ef7da62 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/MapperServiceTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/MapperServiceTestCase.java
@@ -35,20 +35,20 @@
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.compress.CompressedXContent;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalyzerScope;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -155,7 +155,9 @@ protected final MapperService createMapperService(Version version, XContentBuild
             xContentRegistry(),
             similarityService,
             mapperRegistry,
-            () -> { throw new UnsupportedOperationException(); },
+            () -> {
+                throw new UnsupportedOperationException();
+            },
             () -> true,
             scriptService
         );
@@ -183,11 +185,11 @@ protected final SourceToParse source(CheckedConsumer<XContentBuilder, IOExceptio
         XContentBuilder builder = JsonXContent.contentBuilder().startObject();
         build.accept(builder);
         builder.endObject();
-        return new SourceToParse("test", "1", BytesReference.bytes(builder), XContentType.JSON);
+        return new SourceToParse("test", "1", BytesReference.bytes(builder), MediaTypeRegistry.JSON);
     }
 
     protected final SourceToParse source(String source) {
-        return new SourceToParse("test", "1", new BytesArray(source), XContentType.JSON);
+        return new SourceToParse("test", "1", new BytesArray(source), MediaTypeRegistry.JSON);
     }
 
     /**
@@ -249,9 +251,9 @@ QueryShardContext createQueryShardContext(MapperService mapperService) {
             inv -> mapperService.simpleMatchToFullName(inv.getArguments()[0].toString())
         );
         when(queryShardContext.allowExpensiveQueries()).thenReturn(true);
-        when(queryShardContext.lookup()).thenReturn(
-            new SearchLookup(mapperService, (ft, s) -> { throw new UnsupportedOperationException("search lookup not available"); })
-        );
+        when(queryShardContext.lookup()).thenReturn(new SearchLookup(mapperService, (ft, s) -> {
+            throw new UnsupportedOperationException("search lookup not available");
+        }));
         return queryShardContext;
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java b/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
index a64193e55836d..da043229c642d 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
@@ -42,18 +42,17 @@
 import org.apache.lucene.search.NormsFieldExistsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedConsumer;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.fielddata.IndexFieldData;
 import org.opensearch.index.fielddata.IndexFieldDataCache;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.lookup.SearchLookup;
 
@@ -192,7 +191,7 @@ public final void testMinimalSerializesToItself() throws IOException {
         XContentBuilder parsedFromOrig = JsonXContent.contentBuilder().startObject();
         createMapperService(orig).documentMapper().mapping().toXContent(parsedFromOrig, ToXContent.EMPTY_PARAMS);
         parsedFromOrig.endObject();
-        assertEquals(Strings.toString(orig), Strings.toString(parsedFromOrig));
+        assertEquals(orig.toString(), parsedFromOrig.toString());
         assertParseMinimalWarnings();
     }
 
@@ -204,7 +203,7 @@ public void testMinimalToMaximal() throws IOException {
         XContentBuilder parsedFromOrig = JsonXContent.contentBuilder().startObject();
         createMapperService(orig).documentMapper().mapping().toXContent(parsedFromOrig, INCLUDE_DEFAULTS);
         parsedFromOrig.endObject();
-        assertEquals(Strings.toString(orig), Strings.toString(parsedFromOrig));
+        assertEquals(orig.toString(), parsedFromOrig.toString());
         assertParseMaximalWarnings();
     }
 
@@ -274,7 +273,7 @@ public void testDeprecatedBoost() throws IOException {
         }));
         String type = typeName();
         String[] warnings = new String[] {
-            "Parameter [boost] on field [field] is deprecated and will be removed in 8.0",
+            "Parameter [boost] on field [field] is deprecated and will be removed in 3.0",
             "Parameter [boost] has no effect on type [" + type + "] and will be removed in future" };
         allowedWarnings(warnings);
     }
@@ -286,22 +285,22 @@ protected final List<?> fetchFromDocValues(MapperService mapperService, MappedFi
         throws IOException {
 
         BiFunction<MappedFieldType, Supplier<SearchLookup>, IndexFieldData<?>> fieldDataLookup = (mft, lookupSource) -> mft
-            .fielddataBuilder("test", () -> { throw new UnsupportedOperationException(); })
+            .fielddataBuilder("test", () -> {
+                throw new UnsupportedOperationException();
+            })
             .build(new IndexFieldDataCache.None(), new NoneCircuitBreakerService());
         SetOnce<List<?>> result = new SetOnce<>();
-        withLuceneIndex(
-            mapperService,
-            iw -> { iw.addDocument(mapperService.documentMapper().parse(source(b -> b.field(ft.name(), sourceValue))).rootDoc()); },
-            iw -> {
-                SearchLookup lookup = new SearchLookup(mapperService, fieldDataLookup);
-                ValueFetcher valueFetcher = new DocValueFetcher(format, lookup.doc().getForField(ft));
-                IndexSearcher searcher = newSearcher(iw);
-                LeafReaderContext context = searcher.getIndexReader().leaves().get(0);
-                lookup.source().setSegmentAndDocument(context, 0);
-                valueFetcher.setNextReader(context);
-                result.set(valueFetcher.fetchValues(lookup.source()));
-            }
-        );
+        withLuceneIndex(mapperService, iw -> {
+            iw.addDocument(mapperService.documentMapper().parse(source(b -> b.field(ft.name(), sourceValue))).rootDoc());
+        }, iw -> {
+            SearchLookup lookup = new SearchLookup(mapperService, fieldDataLookup);
+            ValueFetcher valueFetcher = new DocValueFetcher(format, lookup.doc().getForField(ft));
+            IndexSearcher searcher = newSearcher(iw);
+            LeafReaderContext context = searcher.getIndexReader().leaves().get(0);
+            lookup.source().setSegmentAndDocument(context, 0);
+            valueFetcher.setNextReader(context);
+            result.set(valueFetcher.fetchValues(lookup.source()));
+        });
         return result.get();
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionTestCase.java b/test/framework/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionTestCase.java
index 10d6a8de139f8..2c3eadb32cafc 100644
--- a/test/framework/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollActionTestCase.java
@@ -33,7 +33,7 @@
 package org.opensearch.index.reindex;
 
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.tasks.TaskId;
+import org.opensearch.core.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
diff --git a/test/framework/src/main/java/org/opensearch/index/replication/OpenSearchIndexLevelReplicationTestCase.java b/test/framework/src/main/java/org/opensearch/index/replication/OpenSearchIndexLevelReplicationTestCase.java
index 6c8e5a8c0a10f..9800782272ede 100644
--- a/test/framework/src/main/java/org/opensearch/index/replication/OpenSearchIndexLevelReplicationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/replication/OpenSearchIndexLevelReplicationTestCase.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.store.AlreadyClosedException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
@@ -52,6 +51,7 @@
 import org.opensearch.action.support.ActionTestUtils;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.action.support.WriteRequest;
+import org.opensearch.action.support.replication.FanoutReplicationProxy;
 import org.opensearch.action.support.replication.PendingReplicationActions;
 import org.opensearch.action.support.replication.ReplicatedWriteRequest;
 import org.opensearch.action.support.replication.ReplicationOperation;
@@ -73,13 +73,16 @@
 import org.opensearch.cluster.routing.TestShardRouting;
 import org.opensearch.common.collect.Iterators;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.engine.DocIdSeqNoAndSource;
 import org.opensearch.index.engine.EngineConfigFactory;
@@ -94,7 +97,6 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.recovery.RecoveryState;
@@ -104,6 +106,7 @@
 import org.opensearch.threadpool.ThreadPool.Names;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
@@ -139,6 +142,30 @@ protected ReplicationGroup createGroup(int replicas, Settings settings) throws I
         return new ReplicationGroup(metadata);
     }
 
+    protected ReplicationGroup createGroup(int replicas, Settings settings, EngineFactory engineFactory) throws IOException {
+        return createGroup(replicas, settings, indexMapping, engineFactory);
+    }
+
+    protected ReplicationGroup createGroup(int replicas, Settings settings, String mappings, EngineFactory engineFactory)
+        throws IOException {
+        Path remotePath = null;
+        if ("true".equals(settings.get(IndexMetadata.SETTING_REMOTE_STORE_ENABLED))) {
+            remotePath = createTempDir();
+        }
+        return createGroup(replicas, settings, mappings, engineFactory, remotePath);
+    }
+
+    protected ReplicationGroup createGroup(int replicas, Settings settings, String mappings, EngineFactory engineFactory, Path remotePath)
+        throws IOException {
+        IndexMetadata metadata = buildIndexMetadata(replicas, settings, mappings);
+        return new ReplicationGroup(metadata, remotePath) {
+            @Override
+            protected EngineFactory getEngineFactory(ShardRouting routing) {
+                return engineFactory;
+            }
+        };
+    }
+
     protected IndexMetadata buildIndexMetadata(int replicas) throws IOException {
         return buildIndexMetadata(replicas, indexMapping);
     }
@@ -191,6 +218,7 @@ protected class ReplicationGroup implements AutoCloseable, Iterable<IndexShard>
         private final AtomicInteger docId = new AtomicInteger();
         boolean closed = false;
         private volatile ReplicationTargets replicationTargets;
+        private final ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS);
 
         private final PrimaryReplicaSyncer primaryReplicaSyncer = new PrimaryReplicaSyncer(
             new TaskManager(Settings.EMPTY, threadPool, Collections.emptySet()),
@@ -212,18 +240,32 @@ protected class ReplicationGroup implements AutoCloseable, Iterable<IndexShard>
             (shardId, primaryAllocationId, primaryTerm, retentionLeases) -> syncRetentionLeases(
                 shardId,
                 retentionLeases,
-                ActionListener.wrap(r -> {}, e -> { throw new AssertionError("failed to background sync retention lease", e); })
+                ActionListener.wrap(r -> {}, e -> {
+                    throw new AssertionError("failed to background sync retention lease", e);
+                })
             )
         );
 
         protected ReplicationGroup(final IndexMetadata indexMetadata) throws IOException {
+            this(indexMetadata, null);
+        }
+
+        protected ReplicationGroup(final IndexMetadata indexMetadata, Path remotePath) throws IOException {
             final ShardRouting primaryRouting = this.createShardRouting("s0", true);
-            primary = newShard(primaryRouting, indexMetadata, null, getEngineFactory(primaryRouting), () -> {}, retentionLeaseSyncer);
+            primary = newShard(
+                primaryRouting,
+                indexMetadata,
+                null,
+                getEngineFactory(primaryRouting),
+                () -> {},
+                retentionLeaseSyncer,
+                remotePath
+            );
             replicas = new CopyOnWriteArrayList<>();
             this.indexMetadata = indexMetadata;
             updateAllocationIDsOnPrimary();
             for (int i = 0; i < indexMetadata.getNumberOfReplicas(); i++) {
-                addReplica();
+                addReplica(remotePath);
             }
         }
 
@@ -248,7 +290,7 @@ protected EngineConfigFactory getEngineConfigFactory(IndexSettings indexSettings
         public int indexDocs(final int numOfDoc) throws Exception {
             for (int doc = 0; doc < numOfDoc; doc++) {
                 final IndexRequest indexRequest = new IndexRequest(index.getName()).id(Integer.toString(docId.incrementAndGet()))
-                    .source("{}", XContentType.JSON);
+                    .source("{}", MediaTypeRegistry.JSON);
                 final BulkItemResponse response = index(indexRequest);
                 if (response.isFailed()) {
                     throw response.getFailure().getCause();
@@ -261,7 +303,7 @@ public int indexDocs(final int numOfDoc) throws Exception {
 
         public int appendDocs(final int numOfDoc) throws Exception {
             for (int doc = 0; doc < numOfDoc; doc++) {
-                final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", XContentType.JSON);
+                final IndexRequest indexRequest = new IndexRequest(index.getName()).source("{}", MediaTypeRegistry.JSON);
                 final BulkItemResponse response = index(indexRequest);
                 if (response.isFailed()) {
                     throw response.getFailure().getCause();
@@ -338,6 +380,10 @@ public void startPrimary() throws IOException {
         }
 
         public IndexShard addReplica() throws IOException {
+            return addReplica((Path) null);
+        }
+
+        public IndexShard addReplica(Path remotePath) throws IOException {
             final ShardRouting replicaRouting = createShardRouting("s" + replicaId.incrementAndGet(), false);
             final IndexShard replica = newShard(
                 replicaRouting,
@@ -345,7 +391,8 @@ public IndexShard addReplica() throws IOException {
                 null,
                 getEngineFactory(replicaRouting),
                 () -> {},
-                retentionLeaseSyncer
+                retentionLeaseSyncer,
+                remotePath
             );
             addReplica(replica);
             return replica;
@@ -386,7 +433,8 @@ public synchronized IndexShard addReplicaWithExistingPath(final ShardPath shardP
                 getEngineConfigFactory(new IndexSettings(indexMetadata, indexMetadata.getSettings())),
                 () -> {},
                 retentionLeaseSyncer,
-                EMPTY_EVENT_LISTENER
+                EMPTY_EVENT_LISTENER,
+                null
             );
             replicas.add(newReplica);
             if (replicationTargets != null) {
@@ -493,7 +541,8 @@ public void recoverReplica(
                 targetSupplier,
                 markAsRecovering,
                 inSyncIds,
-                routingTable
+                routingTable,
+                getReplicationFunc(replica)
             );
             OpenSearchIndexLevelReplicationTestCase.this.startReplicaAfterRecovery(replica, primary, inSyncIds, routingTable);
             computeReplicationTargets();
@@ -573,8 +622,8 @@ public synchronized IndexShard getPrimary() {
             return primary;
         }
 
-        public synchronized void reinitPrimaryShard() throws IOException {
-            primary = reinitShard(primary);
+        public synchronized void reinitPrimaryShard(Path remotePath) throws IOException {
+            primary = reinitShard(primary, remotePath);
             computeReplicationTargets();
         }
 
@@ -708,7 +757,8 @@ public void execute() {
                     opType,
                     primaryTerm,
                     TimeValue.timeValueMillis(20),
-                    TimeValue.timeValueSeconds(60)
+                    TimeValue.timeValueSeconds(60),
+                    new FanoutReplicationProxy<>(new ReplicasRef())
                 ).execute();
             } catch (Exception e) {
                 listener.onFailure(e);
diff --git a/test/framework/src/main/java/org/opensearch/index/replication/TestReplicationSource.java b/test/framework/src/main/java/org/opensearch/index/replication/TestReplicationSource.java
new file mode 100644
index 0000000000000..b29e25a0bff2c
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/index/replication/TestReplicationSource.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.replication;
+
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.index.shard.IndexShard;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.indices.replication.CheckpointInfoResponse;
+import org.opensearch.indices.replication.GetSegmentFilesResponse;
+import org.opensearch.indices.replication.SegmentReplicationSource;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.util.List;
+
+/**
+ * This class is used by unit tests implementing SegmentReplicationSource
+ */
+public abstract class TestReplicationSource implements SegmentReplicationSource {
+
+    @Override
+    public abstract void getCheckpointMetadata(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        ActionListener<CheckpointInfoResponse> listener
+    );
+
+    @Override
+    public abstract void getSegmentFiles(
+        long replicationId,
+        ReplicationCheckpoint checkpoint,
+        List<StoreFileMetadata> filesToFetch,
+        IndexShard indexShard,
+        ActionListener<GetSegmentFilesResponse> listener
+    );
+
+    @Override
+    public String getDescription() {
+        return "This is a test description";
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/index/seqno/RetentionLeaseUtils.java b/test/framework/src/main/java/org/opensearch/index/seqno/RetentionLeaseUtils.java
index bf06b481a2377..8216f1053a60b 100644
--- a/test/framework/src/main/java/org/opensearch/index/seqno/RetentionLeaseUtils.java
+++ b/test/framework/src/main/java/org/opensearch/index/seqno/RetentionLeaseUtils.java
@@ -53,13 +53,8 @@ public static Map<String, RetentionLease> toMapExcludingPeerRecoveryRetentionLea
         return retentionLeases.leases()
             .stream()
             .filter(l -> ReplicationTracker.PEER_RECOVERY_RETENTION_LEASE_SOURCE.equals(l.source()) == false)
-            .collect(
-                Collectors.toMap(
-                    RetentionLease::id,
-                    Function.identity(),
-                    (o1, o2) -> { throw new AssertionError("unexpectedly merging " + o1 + " and " + o2); },
-                    LinkedHashMap::new
-                )
-            );
+            .collect(Collectors.toMap(RetentionLease::id, Function.identity(), (o1, o2) -> {
+                throw new AssertionError("unexpectedly merging " + o1 + " and " + o2);
+            }, LinkedHashMap::new));
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/index/shard/IndexShardTestCase.java b/test/framework/src/main/java/org/opensearch/index/shard/IndexShardTestCase.java
index 509edfd1b9103..186c1c7e78f6b 100644
--- a/test/framework/src/main/java/org/opensearch/index/shard/IndexShardTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/shard/IndexShardTestCase.java
@@ -33,7 +33,11 @@
 
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexCommit;
+import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
 import org.opensearch.action.admin.indices.flush.FlushRequest;
 import org.opensearch.action.index.IndexRequest;
@@ -41,6 +45,7 @@
 import org.opensearch.action.support.replication.TransportReplicationAction;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
@@ -49,19 +54,35 @@
 import org.opensearch.cluster.routing.ShardRoutingHelper;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
+import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesArray;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobMetadata;
+import org.opensearch.common.blobstore.BlobPath;
+import org.opensearch.common.blobstore.BlobStore;
+import org.opensearch.common.blobstore.fs.FsBlobContainer;
+import org.opensearch.common.blobstore.fs.FsBlobStore;
 import org.opensearch.common.concurrent.GatedCloseable;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
+import org.opensearch.env.TestEnvironment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.MapperTestUtils;
 import org.opensearch.index.VersionType;
@@ -73,52 +94,103 @@
 import org.opensearch.index.engine.EngineFactory;
 import org.opensearch.index.engine.EngineTestCase;
 import org.opensearch.index.engine.InternalEngineFactory;
+import org.opensearch.index.engine.NRTReplicationEngineFactory;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.mapper.SourceToParse;
+import org.opensearch.index.remote.RemoteStoreStatsTrackerFactory;
+import org.opensearch.index.remote.RemoteTranslogTransferTracker;
+import org.opensearch.index.replication.TestReplicationSource;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeaseSyncer;
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+import org.opensearch.index.store.RemoteDirectory;
+import org.opensearch.index.store.RemoteSegmentStoreDirectory;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.StoreFileMetadata;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManager;
+import org.opensearch.index.store.lockmanager.RemoteStoreMetadataLockManager;
+import org.opensearch.index.translog.InternalTranslogFactory;
+import org.opensearch.index.translog.RemoteBlobStoreInternalTranslogFactory;
 import org.opensearch.index.translog.Translog;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.index.translog.TranslogFactory;
+import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.indices.recovery.AsyncRecoveryTarget;
+import org.opensearch.indices.recovery.DefaultRecoverySettings;
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryFailedException;
 import org.opensearch.indices.recovery.RecoveryResponse;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.indices.recovery.RecoverySourceHandler;
+import org.opensearch.indices.recovery.RecoverySourceHandlerFactory;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.recovery.RecoveryTarget;
 import org.opensearch.indices.recovery.StartRecoveryRequest;
+import org.opensearch.indices.replication.CheckpointInfoResponse;
+import org.opensearch.indices.replication.GetSegmentFilesResponse;
+import org.opensearch.indices.replication.SegmentReplicationSource;
+import org.opensearch.indices.replication.SegmentReplicationSourceFactory;
+import org.opensearch.indices.replication.SegmentReplicationState;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
+import org.opensearch.indices.replication.SegmentReplicationTargetService;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.common.CopyState;
+import org.opensearch.indices.replication.common.ReplicationCollection;
+import org.opensearch.indices.replication.common.ReplicationFailedException;
+import org.opensearch.indices.replication.common.ReplicationListener;
+import org.opensearch.indices.replication.common.ReplicationState;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.repositories.IndexId;
+import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
+import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
 import org.opensearch.repositories.blobstore.OpenSearchBlobStoreRepositoryIntegTestCase;
+import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.snapshots.Snapshot;
 import org.opensearch.test.DummyShardLock;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+import org.junit.Assert;
 
 import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import org.mockito.Mockito;
+
+import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
+import static org.opensearch.test.ClusterServiceUtils.createClusterService;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
-import static org.opensearch.cluster.routing.TestShardRouting.newShardRouting;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 /**
  * A base class for unit tests that need to create and shutdown {@link IndexShard} instances easily,
@@ -132,32 +204,36 @@ public abstract class IndexShardTestCase extends OpenSearchTestCase {
 
     private static final AtomicBoolean failOnShardFailures = new AtomicBoolean(true);
 
+    private RecoveryTarget recoveryTarget;
+
     private static final Consumer<IndexShard.ShardFailure> DEFAULT_SHARD_FAILURE_HANDLER = failure -> {
         if (failOnShardFailures.get()) {
             throw new AssertionError(failure.reason, failure.cause);
         }
     };
 
-    protected static final PeerRecoveryTargetService.RecoveryListener recoveryListener = new PeerRecoveryTargetService.RecoveryListener() {
+    protected static final ReplicationListener recoveryListener = new ReplicationListener() {
         @Override
-        public void onRecoveryDone(RecoveryState state) {
+        public void onDone(ReplicationState state) {
 
         }
 
         @Override
-        public void onRecoveryFailure(RecoveryState state, RecoveryFailedException e, boolean sendShardFailure) {
+        public void onFailure(ReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
             throw new AssertionError(e);
         }
     };
 
     protected ThreadPool threadPool;
     protected long primaryTerm;
+    protected ClusterService clusterService;
 
     @Override
     public void setUp() throws Exception {
         super.setUp();
         threadPool = setUpThreadPool();
         primaryTerm = randomIntBetween(1, 100); // use random but fixed term for creating shards
+        clusterService = createClusterService(threadPool);
         failOnShardFailures();
     }
 
@@ -169,6 +245,7 @@ protected ThreadPool setUpThreadPool() {
     public void tearDown() throws Exception {
         try {
             tearDownThreadPool();
+            clusterService.close();
         } finally {
             super.tearDown();
         }
@@ -196,11 +273,17 @@ public Settings threadPoolSettings() {
     }
 
     protected Store createStore(IndexSettings indexSettings, ShardPath shardPath) throws IOException {
-        return createStore(shardPath.getShardId(), indexSettings, newFSDirectory(shardPath.resolveIndex()));
+        return createStore(shardPath.getShardId(), indexSettings, newFSDirectory(shardPath.resolveIndex()), shardPath);
     }
 
-    protected Store createStore(ShardId shardId, IndexSettings indexSettings, Directory directory) throws IOException {
-        return new Store(shardId, indexSettings, directory, new DummyShardLock(shardId));
+    protected Store createStore(ShardId shardId, IndexSettings indexSettings, Directory directory, ShardPath shardPath) throws IOException {
+        return new Store(shardId, indexSettings, directory, new DummyShardLock(shardId), Store.OnClose.EMPTY, shardPath);
+    }
+
+    protected Releasable acquirePrimaryOperationPermitBlockingly(IndexShard indexShard) throws ExecutionException, InterruptedException {
+        PlainActionFuture<Releasable> fut = new PlainActionFuture<>();
+        indexShard.acquirePrimaryOperationPermit(fut, ThreadPool.Names.WRITE, "");
+        return fut.get();
     }
 
     /**
@@ -280,7 +363,7 @@ protected IndexShard newShard(
             .settings(indexSettings)
             .primaryTerm(0, primaryTerm)
             .putMapping("{ \"properties\": {} }");
-        return newShard(shardRouting, metadata.build(), null, engineFactory, () -> {}, RetentionLeaseSyncer.EMPTY, listeners);
+        return newShard(shardRouting, metadata.build(), null, engineFactory, () -> {}, RetentionLeaseSyncer.EMPTY, null, listeners);
     }
 
     /**
@@ -349,7 +432,8 @@ protected IndexShard newShard(
             readerWrapper,
             new InternalEngineFactory(),
             globalCheckpointSyncer,
-            RetentionLeaseSyncer.EMPTY
+            RetentionLeaseSyncer.EMPTY,
+            null
         );
     }
 
@@ -368,7 +452,7 @@ protected IndexShard newShard(
         EngineFactory engineFactory,
         IndexingOperationListener... listeners
     ) throws IOException {
-        return newShard(routing, indexMetadata, indexReaderWrapper, engineFactory, () -> {}, RetentionLeaseSyncer.EMPTY, listeners);
+        return newShard(routing, indexMetadata, indexReaderWrapper, engineFactory, () -> {}, RetentionLeaseSyncer.EMPTY, null, listeners);
     }
 
     /**
@@ -387,6 +471,7 @@ protected IndexShard newShard(
         @Nullable EngineFactory engineFactory,
         Runnable globalCheckpointSyncer,
         RetentionLeaseSyncer retentionLeaseSyncer,
+        Path path,
         IndexingOperationListener... listeners
     ) throws IOException {
         // add node id as name to settings for proper logging
@@ -404,10 +489,106 @@ protected IndexShard newShard(
             globalCheckpointSyncer,
             retentionLeaseSyncer,
             EMPTY_EVENT_LISTENER,
+            path,
             listeners
         );
     }
 
+    /**
+     * creates a new initializing shard. The shard will will be put in its proper path under the
+     * current node id the shard is assigned to.
+     * @param routing                       shard routing to use
+     * @param shardPath                     path to use for shard data
+     * @param indexMetadata                 indexMetadata for the shard, including any mapping
+     * @param storeProvider                 an optional custom store provider to use. If null a default file based store will be created
+     * @param indexReaderWrapper            an optional wrapper to be used during search
+     * @param globalCheckpointSyncer        callback for syncing global checkpoints
+     * @param indexEventListener            index event listener
+     * @param listeners                     an optional set of listeners to add to the shard
+     */
+    protected IndexShard newShard(
+        ShardRouting routing,
+        ShardPath shardPath,
+        IndexMetadata indexMetadata,
+        @Nullable CheckedFunction<IndexSettings, Store, IOException> storeProvider,
+        @Nullable CheckedFunction<DirectoryReader, DirectoryReader, IOException> indexReaderWrapper,
+        @Nullable EngineFactory engineFactory,
+        @Nullable EngineConfigFactory engineConfigFactory,
+        Runnable globalCheckpointSyncer,
+        RetentionLeaseSyncer retentionLeaseSyncer,
+        IndexEventListener indexEventListener,
+        Path remotePath,
+        IndexingOperationListener... listeners
+    ) throws IOException {
+        return newShard(
+            routing,
+            shardPath,
+            indexMetadata,
+            storeProvider,
+            indexReaderWrapper,
+            engineFactory,
+            engineConfigFactory,
+            globalCheckpointSyncer,
+            retentionLeaseSyncer,
+            indexEventListener,
+            SegmentReplicationCheckpointPublisher.EMPTY,
+            remotePath,
+            listeners
+        );
+    }
+
+    protected IndexShard newShard(boolean primary, SegmentReplicationCheckpointPublisher checkpointPublisher) throws IOException {
+        final Settings settings = Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT).build();
+        return newShard(primary, checkpointPublisher, settings);
+    }
+
+    /**
+     * creates a new initializing shard. The shard will be put in its proper path under the
+     * current node id the shard is assigned to.
+     * @param checkpointPublisher               Segment Replication Checkpoint Publisher to publish checkpoint
+     */
+    protected IndexShard newShard(boolean primary, SegmentReplicationCheckpointPublisher checkpointPublisher, Settings settings)
+        throws IOException {
+        final ShardId shardId = new ShardId("index", "_na_", 0);
+        final ShardRouting shardRouting = TestShardRouting.newShardRouting(
+            shardId,
+            randomAlphaOfLength(10),
+            primary,
+            ShardRoutingState.INITIALIZING,
+            primary ? RecoverySource.EmptyStoreRecoverySource.INSTANCE : RecoverySource.PeerRecoverySource.INSTANCE
+        );
+        final NodeEnvironment.NodePath nodePath = new NodeEnvironment.NodePath(createTempDir());
+        ShardPath shardPath = new ShardPath(false, nodePath.resolve(shardId), nodePath.resolve(shardId), shardId);
+
+        Settings indexSettings = Settings.builder()
+            .put(settings)
+            .put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexSettings.INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING.getKey(), between(0, 1000))
+            .put(Settings.EMPTY)
+            .build();
+        IndexMetadata metadata = IndexMetadata.builder(shardRouting.getIndexName())
+            .settings(indexSettings)
+            .primaryTerm(0, primaryTerm)
+            .putMapping("{ \"properties\": {} }")
+            .build();
+        return newShard(
+            shardRouting,
+            shardPath,
+            metadata,
+            null,
+            null,
+            new NRTReplicationEngineFactory(),
+            new EngineConfigFactory(new IndexSettings(metadata, metadata.getSettings())),
+            () -> {},
+            RetentionLeaseSyncer.EMPTY,
+            EMPTY_EVENT_LISTENER,
+            checkpointPublisher,
+            null
+        );
+    }
+
     /**
      * creates a new initializing shard.
      * @param routing                       shard routing to use
@@ -417,6 +598,7 @@ protected IndexShard newShard(
      * @param indexReaderWrapper            an optional wrapper to be used during search
      * @param globalCheckpointSyncer        callback for syncing global checkpoints
      * @param indexEventListener            index event listener
+     * @param checkpointPublisher           segment Replication Checkpoint Publisher to publish checkpoint
      * @param listeners                     an optional set of listeners to add to the shard
      */
     protected IndexShard newShard(
@@ -430,6 +612,8 @@ protected IndexShard newShard(
         Runnable globalCheckpointSyncer,
         RetentionLeaseSyncer retentionLeaseSyncer,
         IndexEventListener indexEventListener,
+        SegmentReplicationCheckpointPublisher checkpointPublisher,
+        @Nullable Path remotePath,
         IndexingOperationListener... listeners
     ) throws IOException {
         final Settings nodeSettings = Settings.builder().put("node.name", routing.currentNodeId()).build();
@@ -457,6 +641,40 @@ protected IndexShard newShard(
                 Collections.emptyList(),
                 clusterSettings
             );
+            Store remoteStore;
+            RemoteStoreStatsTrackerFactory remoteStoreStatsTrackerFactory = null;
+            RepositoriesService mockRepoSvc = mock(RepositoriesService.class);
+
+            if (indexSettings.isRemoteStoreEnabled()) {
+                String remoteStoreRepository = indexSettings.getRemoteStoreRepository();
+                // remote path via setting a repository . This is a hack used for shards are created using reset .
+                // since we can't get remote path from IndexShard directly, we are using repository to store it .
+                if (remoteStoreRepository != null && remoteStoreRepository.endsWith("__test")) {
+                    remotePath = PathUtils.get(remoteStoreRepository.replace("__test", ""));
+                } else if (remotePath == null) {
+                    remotePath = createTempDir();
+                }
+
+                remoteStore = createRemoteStore(remotePath, routing, indexMetadata, shardPath);
+
+                remoteStoreStatsTrackerFactory = new RemoteStoreStatsTrackerFactory(clusterService, indexSettings.getSettings());
+                BlobStoreRepository repo = createRepository(remotePath);
+                when(mockRepoSvc.repository(any())).thenAnswer(invocationOnMock -> repo);
+            } else {
+                remoteStore = null;
+            }
+
+            final BiFunction<IndexSettings, ShardRouting, TranslogFactory> translogFactorySupplier = (settings, shardRouting) -> {
+                if (settings.isRemoteTranslogStoreEnabled() && shardRouting.primary()) {
+                    return new RemoteBlobStoreInternalTranslogFactory(
+                        () -> mockRepoSvc,
+                        threadPool,
+                        settings.getRemoteStoreTranslogRepository(),
+                        new RemoteTranslogTransferTracker(shardRouting.shardId(), 20)
+                    );
+                }
+                return new InternalTranslogFactory();
+            };
             indexShard = new IndexShard(
                 routing,
                 indexSettings,
@@ -477,9 +695,19 @@ protected IndexShard newShard(
                 Arrays.asList(listeners),
                 globalCheckpointSyncer,
                 retentionLeaseSyncer,
-                breakerService
+                breakerService,
+                translogFactorySupplier,
+                checkpointPublisher,
+                remoteStore,
+                remoteStoreStatsTrackerFactory,
+                () -> IndexSettings.DEFAULT_REMOTE_TRANSLOG_BUFFER_INTERVAL,
+                "dummy-node",
+                null
             );
             indexShard.addShardFailureCallback(DEFAULT_SHARD_FAILURE_HANDLER);
+            if (remoteStoreStatsTrackerFactory != null) {
+                remoteStoreStatsTrackerFactory.afterIndexShardCreated(indexShard);
+            }
             success = true;
         } finally {
             if (success == false) {
@@ -489,12 +717,110 @@ protected IndexShard newShard(
         return indexShard;
     }
 
+    private BlobStoreRepository createRepository(Path path) {
+        Settings settings = Settings.builder().put("location", path).build();
+        RepositoryMetadata repositoryMetadata = new RepositoryMetadata(randomAlphaOfLength(10), FsRepository.TYPE, settings);
+        final ClusterService clusterService = BlobStoreTestUtil.mockClusterService(repositoryMetadata);
+        final FsRepository repository = new FsRepository(
+            repositoryMetadata,
+            createEnvironment(path),
+            xContentRegistry(),
+            clusterService,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS))
+        ) {
+            @Override
+            protected void assertSnapshotOrGenericThread() {
+                // eliminate thread name check as we create repo manually
+            }
+        };
+        clusterService.addStateApplier(event -> repository.updateState(event.state()));
+        // Apply state once to initialize repo properly like RepositoriesService would
+        repository.updateState(clusterService.state());
+        repository.start();
+        return repository;
+    }
+
+    private Environment createEnvironment(Path path) {
+        Path home = createTempDir();
+        return TestEnvironment.newEnvironment(
+            Settings.builder()
+                .put(Environment.PATH_HOME_SETTING.getKey(), home.toAbsolutePath())
+                .put(Environment.PATH_REPO_SETTING.getKey(), path.toAbsolutePath())
+                .build()
+        );
+    }
+
+    protected RepositoriesService createRepositoriesService() {
+        RepositoriesService repositoriesService = Mockito.mock(RepositoriesService.class);
+        BlobStoreRepository repository = Mockito.mock(BlobStoreRepository.class);
+        when(repository.basePath()).thenReturn(new BlobPath());
+        BlobStore blobStore = Mockito.mock(BlobStore.class);
+        BlobContainer blobContainer = Mockito.mock(BlobContainer.class);
+        doAnswer(invocation -> {
+            ActionListener<List<BlobMetadata>> listener = invocation.getArgument(3);
+            listener.onResponse(new ArrayList<>());
+            return null;
+        }).when(blobContainer)
+            .listBlobsByPrefixInSortedOrder(
+                any(String.class),
+                anyInt(),
+                any(BlobContainer.BlobNameSortOrder.class),
+                any(ActionListener.class)
+            );
+        when(blobStore.blobContainer(any())).thenReturn(blobContainer);
+        when(repository.blobStore()).thenReturn(blobStore);
+        when(repositoriesService.repository(any(String.class))).thenReturn(repository);
+        return repositoriesService;
+    }
+
+    protected Store createRemoteStore(Path path, ShardRouting shardRouting, IndexMetadata metadata, ShardPath shardPath)
+        throws IOException {
+        Settings nodeSettings = Settings.builder().put("node.name", shardRouting.currentNodeId()).build();
+        ShardId shardId = shardRouting.shardId();
+        RemoteSegmentStoreDirectory remoteSegmentStoreDirectory = createRemoteSegmentStoreDirectory(shardId, path);
+        return createStore(shardId, new IndexSettings(metadata, nodeSettings), remoteSegmentStoreDirectory, shardPath);
+    }
+
+    protected RemoteSegmentStoreDirectory createRemoteSegmentStoreDirectory(ShardId shardId, Path path) throws IOException {
+        NodeEnvironment.NodePath remoteNodePath = new NodeEnvironment.NodePath(path);
+        ShardPath remoteShardPath = new ShardPath(false, remoteNodePath.resolve(shardId), remoteNodePath.resolve(shardId), shardId);
+        RemoteDirectory dataDirectory = newRemoteDirectory(remoteShardPath.resolveIndex());
+        RemoteDirectory metadataDirectory = newRemoteDirectory(remoteShardPath.resolveIndex());
+        RemoteStoreLockManager remoteStoreLockManager = new RemoteStoreMetadataLockManager(
+            new RemoteBufferedOutputDirectory(getBlobContainer(remoteShardPath.resolveIndex()))
+        );
+        return new RemoteSegmentStoreDirectory(
+            dataDirectory,
+            metadataDirectory,
+            remoteStoreLockManager,
+            threadPool,
+            shardId,
+            DefaultRecoverySettings.INSTANCE
+        );
+    }
+
+    private RemoteDirectory newRemoteDirectory(Path f) throws IOException {
+        return new RemoteDirectory(getBlobContainer(f));
+    }
+
+    protected BlobContainer getBlobContainer(Path f) throws IOException {
+        FsBlobStore fsBlobStore = new FsBlobStore(1024, f, false);
+        BlobPath blobPath = new BlobPath();
+        return new FsBlobContainer(fsBlobStore, blobPath, f);
+    }
+
+    protected IndexShard reinitShard(IndexShard current, IndexingOperationListener... listeners) throws IOException {
+        return reinitShard(current, (Path) null, listeners);
+    }
+
     /**
      * Takes an existing shard, closes it and starts a new initialing shard at the same location
      *
+     * @param current The current shard to reinit
+     * @param remotePath Remote path to recover from if remote storage is used
      * @param listeners new listerns to use for the newly created shard
      */
-    protected IndexShard reinitShard(IndexShard current, IndexingOperationListener... listeners) throws IOException {
+    protected IndexShard reinitShard(IndexShard current, Path remotePath, IndexingOperationListener... listeners) throws IOException {
         final ShardRouting shardRouting = current.routingEntry();
         return reinitShard(
             current,
@@ -502,6 +828,7 @@ protected IndexShard reinitShard(IndexShard current, IndexingOperationListener..
                 shardRouting,
                 shardRouting.primary() ? RecoverySource.ExistingStoreRecoverySource.INSTANCE : RecoverySource.PeerRecoverySource.INSTANCE
             ),
+            remotePath,
             listeners
         );
     }
@@ -513,12 +840,18 @@ protected IndexShard reinitShard(IndexShard current, IndexingOperationListener..
      * @param listeners new listerns to use for the newly created shard
      */
     protected IndexShard reinitShard(IndexShard current, ShardRouting routing, IndexingOperationListener... listeners) throws IOException {
+        return reinitShard(current, routing, null, listeners);
+    }
+
+    protected IndexShard reinitShard(IndexShard current, ShardRouting routing, Path remotePath, IndexingOperationListener... listeners)
+        throws IOException {
         return reinitShard(
             current,
             routing,
             current.indexSettings.getIndexMetadata(),
             current.engineFactory,
             current.engineConfigFactory,
+            remotePath,
             listeners
         );
     }
@@ -537,6 +870,7 @@ protected IndexShard reinitShard(
         IndexMetadata indexMetadata,
         EngineFactory engineFactory,
         EngineConfigFactory engineConfigFactory,
+        Path remotePath,
         IndexingOperationListener... listeners
     ) throws IOException {
         closeShards(current);
@@ -551,6 +885,7 @@ protected IndexShard reinitShard(
             current.getGlobalCheckpointSyncer(),
             current.getRetentionLeaseSyncer(),
             EMPTY_EVENT_LISTENER,
+            remotePath,
             listeners
         );
     }
@@ -633,7 +968,7 @@ protected void closeShard(IndexShard shard, boolean assertConsistencyBetweenTran
                 EngineTestCase.assertAtMostOneLuceneDocumentPerSequenceNumber(engine);
             }
         } finally {
-            IOUtils.close(() -> shard.close("test", false), shard.store());
+            IOUtils.close(() -> shard.close("test", false, false), shard.store());
         }
     }
 
@@ -690,18 +1025,57 @@ protected DiscoveryNode getFakeDiscoNode(String id) {
         );
     }
 
-    /** recovers a replica from the given primary **/
     protected void recoverReplica(IndexShard replica, IndexShard primary, boolean startReplica) throws IOException {
-        recoverReplica(replica, primary, (r, sourceNode) -> new RecoveryTarget(r, sourceNode, recoveryListener), true, startReplica);
+        recoverReplica(replica, primary, startReplica, getReplicationFunc(replica));
     }
 
     /** recovers a replica from the given primary **/
+    protected void recoverReplica(
+        IndexShard replica,
+        IndexShard primary,
+        boolean startReplica,
+        Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction
+    ) throws IOException {
+        recoverReplica(
+            replica,
+            primary,
+            (r, sourceNode) -> new RecoveryTarget(r, sourceNode, recoveryListener),
+            true,
+            startReplica,
+            replicatePrimaryFunction
+        );
+    }
+
     protected void recoverReplica(
         final IndexShard replica,
         final IndexShard primary,
         final BiFunction<IndexShard, DiscoveryNode, RecoveryTarget> targetSupplier,
         final boolean markAsRecovering,
         final boolean markAsStarted
+    ) throws IOException {
+        recoverReplica(replica, primary, targetSupplier, markAsRecovering, markAsStarted, (a) -> null);
+    }
+
+    public Function<List<IndexShard>, List<SegmentReplicationTarget>> getReplicationFunc(final IndexShard target) {
+        return target.indexSettings().isSegRepEnabled() ? (shardList) -> {
+            try {
+                assert shardList.size() >= 2;
+                final IndexShard primary = shardList.get(0);
+                return replicateSegments(primary, shardList.subList(1, shardList.size()));
+            } catch (IOException | InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        } : (a) -> null;
+    }
+
+    /** recovers a replica from the given primary **/
+    protected void recoverReplica(
+        final IndexShard replica,
+        final IndexShard primary,
+        final BiFunction<IndexShard, DiscoveryNode, RecoveryTarget> targetSupplier,
+        final boolean markAsRecovering,
+        final boolean markAsStarted,
+        final Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction
     ) throws IOException {
         IndexShardRoutingTable.Builder newRoutingTable = new IndexShardRoutingTable.Builder(replica.shardId());
         newRoutingTable.addShard(primary.routingEntry());
@@ -710,7 +1084,7 @@ protected void recoverReplica(
         }
         final Set<String> inSyncIds = Collections.singleton(primary.routingEntry().allocationId().getId());
         final IndexShardRoutingTable routingTable = newRoutingTable.build();
-        recoverUnstartedReplica(replica, primary, targetSupplier, markAsRecovering, inSyncIds, routingTable);
+        recoverUnstartedReplica(replica, primary, targetSupplier, markAsRecovering, inSyncIds, routingTable, replicatePrimaryFunction);
         if (markAsStarted) {
             startReplicaAfterRecovery(replica, primary, inSyncIds, routingTable);
         }
@@ -733,7 +1107,8 @@ protected final void recoverUnstartedReplica(
         final BiFunction<IndexShard, DiscoveryNode, RecoveryTarget> targetSupplier,
         final boolean markAsRecovering,
         final Set<String> inSyncIds,
-        final IndexShardRoutingTable routingTable
+        final IndexShardRoutingTable routingTable,
+        final Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction
     ) throws IOException {
         final DiscoveryNode pNode = getFakeDiscoNode(primary.routingEntry().currentNodeId());
         final DiscoveryNode rNode = getFakeDiscoNode(replica.routingEntry().currentNodeId());
@@ -744,24 +1119,32 @@ protected final void recoverUnstartedReplica(
         }
         replica.prepareForIndexRecovery();
         final RecoveryTarget recoveryTarget = targetSupplier.apply(replica, pNode);
-        final long startingSeqNo = recoveryTarget.indexShard().recoverLocallyUpToGlobalCheckpoint();
+        IndexShard indexShard = recoveryTarget.indexShard();
+        boolean remoteTranslogEnabled = recoveryTarget.state().getPrimary() == false && indexShard.isRemoteTranslogEnabled();
+        final long startingSeqNo = indexShard.recoverLocallyAndFetchStartSeqNo(!remoteTranslogEnabled);
         final StartRecoveryRequest request = PeerRecoveryTargetService.getStartRecoveryRequest(
             logger,
             rNode,
             recoveryTarget,
             startingSeqNo
         );
-        int fileChunkSizeInBytes = Math.toIntExact(
-            randomBoolean() ? RecoverySettings.DEFAULT_CHUNK_SIZE.getBytes() : randomIntBetween(1, 10 * 1024 * 1024)
+        long fileChunkSizeInBytes = randomBoolean()
+            ? RecoverySettings.DEFAULT_CHUNK_SIZE.getBytes()
+            : randomIntBetween(1, 10 * 1024 * 1024);
+        final Settings settings = Settings.builder()
+            .put("indices.recovery.max_concurrent_file_chunks", Integer.toString(between(1, 4)))
+            .put("indices.recovery.max_concurrent_operations", Integer.toString(between(1, 4)))
+            .build();
+        RecoverySettings recoverySettings = new RecoverySettings(
+            settings,
+            new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
         );
-        final RecoverySourceHandler recovery = new RecoverySourceHandler(
+        recoverySettings.setChunkSize(new ByteSizeValue(fileChunkSizeInBytes));
+        final RecoverySourceHandler recovery = RecoverySourceHandlerFactory.create(
             primary,
-            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic()),
-            threadPool,
+            new AsyncRecoveryTarget(recoveryTarget, threadPool.generic(), primary, replica, replicatePrimaryFunction),
             request,
-            fileChunkSizeInBytes,
-            between(1, 8),
-            between(1, 8)
+            recoverySettings
         );
         primary.updateShardState(
             primary.routingEntry(),
@@ -877,12 +1260,12 @@ protected Engine.IndexResult indexDoc(IndexShard shard, String type, String id)
     }
 
     protected Engine.IndexResult indexDoc(IndexShard shard, String type, String id, String source) throws IOException {
-        return indexDoc(shard, id, source, XContentType.JSON, null);
+        return indexDoc(shard, id, source, MediaTypeRegistry.JSON, null);
     }
 
-    protected Engine.IndexResult indexDoc(IndexShard shard, String id, String source, XContentType xContentType, String routing)
+    protected Engine.IndexResult indexDoc(IndexShard shard, String id, String source, MediaType mediaType, String routing)
         throws IOException {
-        SourceToParse sourceToParse = new SourceToParse(shard.shardId().getIndexName(), id, new BytesArray(source), xContentType, routing);
+        SourceToParse sourceToParse = new SourceToParse(shard.shardId().getIndexName(), id, new BytesArray(source), mediaType, routing);
         Engine.IndexResult result;
         if (shard.routingEntry().primary()) {
             result = shard.applyIndexOperationOnPrimary(
@@ -917,6 +1300,7 @@ protected Engine.IndexResult indexDoc(IndexShard shard, String id, String source
             final long seqNo = shard.seqNoStats().getMaxSeqNo() + 1;
             shard.advanceMaxSeqNoOfUpdatesOrDeletes(seqNo); // manually replicate max_seq_no_of_updates
             result = shard.applyIndexOperationOnReplica(
+                UUID.randomUUID().toString(),
                 seqNo,
                 shard.getOperationPrimaryTerm(),
                 0,
@@ -1068,4 +1452,241 @@ public static Engine.Warmer createTestWarmer(IndexSettings indexSettings) {
             }
         };
     }
+
+    private SegmentReplicationTargetService getSegmentReplicationTargetService(
+        TransportService transportService,
+        IndicesService indicesService,
+        ClusterService clusterService,
+        SegmentReplicationSourceFactory sourceFactory
+    ) {
+        return new SegmentReplicationTargetService(
+            threadPool,
+            new RecoverySettings(Settings.EMPTY, new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)),
+            transportService,
+            sourceFactory,
+            indicesService,
+            clusterService
+        );
+    }
+
+    /**
+     * Segment Replication specific test method - Creates a {@link SegmentReplicationTargetService} to perform replications that has
+     * been configured to return the given primaryShard's current segments. In order to do so, it mimics the replication
+     * source (to avoid transport calls) and simply copies over the segment files from primary store to replica's as part of
+     * get_files calls.
+     *
+     * @param primaryShard {@link IndexShard} - The target replica shard in segment replication.
+     * @param target {@link IndexShard} - The source primary shard in segment replication.
+     * @param transportService {@link TransportService} - Transport service to be used on target
+     * @param indicesService {@link IndicesService} - The indices service to be used on target
+     * @param clusterService {@link ClusterService} - The cluster service to be used on target
+     * @param postGetFilesRunnable - Consumer which is executed after file copy operation. This can be used to stub operations
+     *                             which are desired right after files are copied. e.g. To work with temp files
+     * @return Returns SegmentReplicationTargetService
+     */
+    private SegmentReplicationTargetService prepareForReplication(
+        IndexShard primaryShard,
+        IndexShard target,
+        TransportService transportService,
+        IndicesService indicesService,
+        ClusterService clusterService,
+        Consumer<IndexShard> postGetFilesRunnable
+    ) {
+
+        SegmentReplicationSourceFactory sourceFactory = null;
+        SegmentReplicationTargetService targetService;
+        if (primaryShard.indexSettings.isRemoteStoreEnabled()) {
+            RecoverySettings recoverySettings = new RecoverySettings(
+                Settings.EMPTY,
+                new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+            );
+            sourceFactory = new SegmentReplicationSourceFactory(transportService, recoverySettings, clusterService);
+            targetService = getSegmentReplicationTargetService(transportService, indicesService, clusterService, sourceFactory);
+        } else {
+            sourceFactory = mock(SegmentReplicationSourceFactory.class);
+            targetService = getSegmentReplicationTargetService(transportService, indicesService, clusterService, sourceFactory);
+            final SegmentReplicationSource replicationSource = getSegmentReplicationSource(
+                primaryShard,
+                (repId) -> targetService.get(repId),
+                postGetFilesRunnable
+            );
+            when(sourceFactory.get(any())).thenReturn(replicationSource);
+            // This is needed for force segment sync call. Remote store uses a different recovery mechanism
+            when(indicesService.getShardOrNull(any())).thenReturn(target);
+        }
+        return targetService;
+    }
+
+    /**
+     * Segment Replication specific test method - Creates a {@link SegmentReplicationTargetService} to perform replications that has
+     * been configured to return the given primaryShard's current segments.
+     *
+     * @param primaryShard {@link IndexShard} - The primary shard to replicate from.
+     * @param target {@link IndexShard} - The target replica shard.
+     * @return Returns SegmentReplicationTargetService
+     */
+    public final SegmentReplicationTargetService prepareForReplication(IndexShard primaryShard, IndexShard target) {
+        return prepareForReplication(
+            primaryShard,
+            target,
+            mock(TransportService.class),
+            mock(IndicesService.class),
+            mock(ClusterService.class),
+            (indexShard) -> {}
+        );
+    }
+
+    public final SegmentReplicationTargetService prepareForReplication(
+        IndexShard primaryShard,
+        IndexShard target,
+        TransportService transportService,
+        IndicesService indicesService,
+        ClusterService clusterService
+    ) {
+        return prepareForReplication(primaryShard, target, transportService, indicesService, clusterService, (indexShard) -> {});
+    }
+
+    /**
+     * Get listener on started segment replication event which verifies replica shard store with primary's after completion
+     * @param primaryShard - source of segment replication
+     * @param replicaShard - target of segment replication
+     * @param primaryMetadata - primary shard metadata before start of segment replication
+     * @param latch - Latch which allows consumers of this utility to ensure segment replication completed successfully
+     * @return Returns SegmentReplicationTargetService.SegmentReplicationListener
+     */
+    public SegmentReplicationTargetService.SegmentReplicationListener getTargetListener(
+        IndexShard primaryShard,
+        IndexShard replicaShard,
+        Map<String, StoreFileMetadata> primaryMetadata,
+        CountDownLatch latch
+    ) {
+        return new SegmentReplicationTargetService.SegmentReplicationListener() {
+            @Override
+            public void onReplicationDone(SegmentReplicationState state) {
+                try (final GatedCloseable<SegmentInfos> snapshot = replicaShard.getSegmentInfosSnapshot()) {
+                    final SegmentInfos replicaInfos = snapshot.get();
+                    final Map<String, StoreFileMetadata> replicaMetadata = replicaShard.store().getSegmentMetadataMap(replicaInfos);
+                    final Store.RecoveryDiff recoveryDiff = Store.segmentReplicationDiff(primaryMetadata, replicaMetadata);
+                    assertTrue(recoveryDiff.missing.isEmpty());
+                    assertTrue(recoveryDiff.different.isEmpty());
+                    assertEquals(recoveryDiff.identical.size(), primaryMetadata.size());
+                    primaryShard.updateVisibleCheckpointForShard(
+                        replicaShard.routingEntry().allocationId().getId(),
+                        primaryShard.getLatestReplicationCheckpoint()
+                    );
+                } catch (Exception e) {
+                    throw ExceptionsHelper.convertToRuntime(e);
+                } finally {
+                    latch.countDown();
+                }
+            }
+
+            @Override
+            public void onReplicationFailure(SegmentReplicationState state, ReplicationFailedException e, boolean sendShardFailure) {
+                logger.error("Unexpected replication failure in test", e);
+                Assert.fail("test replication should not fail: " + e);
+            }
+        };
+    }
+
+    /**
+     * Utility method which creates a segment replication source, which copies files from primary shard to target shard
+     * @param primaryShard Primary IndexShard - source of segment replication
+     * @param getTargetFunc - provides replication target from target service using replication id
+     * @param postGetFilesRunnable - Consumer which is executed after file copy operation. This can be used to stub operations
+     *                             which are desired right after files are copied. e.g. To work with temp files
+     * @return Return SegmentReplicationSource
+     */
+    public SegmentReplicationSource getSegmentReplicationSource(
+        IndexShard primaryShard,
+        Function<Long, ReplicationCollection.ReplicationRef<SegmentReplicationTarget>> getTargetFunc,
+        Consumer<IndexShard> postGetFilesRunnable
+    ) {
+        return new TestReplicationSource() {
+            @Override
+            public void getCheckpointMetadata(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                ActionListener<CheckpointInfoResponse> listener
+            ) {
+                try {
+                    final CopyState copyState = new CopyState(primaryShard.getLatestReplicationCheckpoint(), primaryShard);
+                    listener.onResponse(
+                        new CheckpointInfoResponse(copyState.getCheckpoint(), copyState.getMetadataMap(), copyState.getInfosBytes())
+                    );
+                    copyState.decRef();
+                } catch (IOException e) {
+                    logger.error("Unexpected error computing CopyState", e);
+                    Assert.fail("Failed to compute copyState");
+                }
+            }
+
+            @Override
+            public void getSegmentFiles(
+                long replicationId,
+                ReplicationCheckpoint checkpoint,
+                List<StoreFileMetadata> filesToFetch,
+                IndexShard indexShard,
+                ActionListener<GetSegmentFilesResponse> listener
+            ) {
+                try (
+                    final ReplicationCollection.ReplicationRef<SegmentReplicationTarget> replicationRef = getTargetFunc.apply(replicationId)
+                ) {
+                    writeFileChunks(replicationRef.get(), primaryShard, filesToFetch.toArray(new StoreFileMetadata[] {}));
+                } catch (IOException e) {
+                    listener.onFailure(e);
+                }
+                postGetFilesRunnable.accept(indexShard);
+                listener.onResponse(new GetSegmentFilesResponse(filesToFetch));
+            }
+        };
+    }
+
+    /**
+     * Segment Replication specific test method - Replicate segments to a list of replicas from a given primary.
+     * This test will use a real {@link SegmentReplicationTarget} for each replica with a mock {@link SegmentReplicationSource} that
+     * writes all segments directly to the target.
+     * @param primaryShard - {@link IndexShard} The current primary shard.
+     * @param replicaShards - Replicas that will be updated.
+     * @return {@link List} List of target components orchestrating replication.
+     */
+    protected final List<SegmentReplicationTarget> replicateSegments(IndexShard primaryShard, List<IndexShard> replicaShards)
+        throws IOException, InterruptedException {
+        // Latch to block test execution until replica catches up
+        final CountDownLatch countDownLatch = new CountDownLatch(replicaShards.size());
+        // Get primary metadata to verify with replica's, used to ensure replica catches up
+        Map<String, StoreFileMetadata> primaryMetadata;
+        try (final GatedCloseable<SegmentInfos> segmentInfosSnapshot = primaryShard.getSegmentInfosSnapshot()) {
+            final SegmentInfos primarySegmentInfos = segmentInfosSnapshot.get();
+            primaryMetadata = primaryShard.store().getSegmentMetadataMap(primarySegmentInfos);
+        }
+        List<SegmentReplicationTarget> ids = new ArrayList<>();
+        for (IndexShard replica : replicaShards) {
+            final SegmentReplicationTargetService targetService = prepareForReplication(primaryShard, replica);
+            final SegmentReplicationTarget target = targetService.startReplication(
+                replica,
+                primaryShard.getLatestReplicationCheckpoint(),
+                getTargetListener(primaryShard, replica, primaryMetadata, countDownLatch)
+            );
+            ids.add(target);
+        }
+        countDownLatch.await(30, TimeUnit.SECONDS);
+        assertEquals("Replication should complete successfully", 0, countDownLatch.getCount());
+        return ids;
+    }
+
+    private void writeFileChunks(SegmentReplicationTarget target, IndexShard primary, StoreFileMetadata[] files) throws IOException {
+        for (StoreFileMetadata md : files) {
+            try (IndexInput in = primary.store().directory().openInput(md.name(), IOContext.READONCE)) {
+                int pos = 0;
+                while (pos < md.length()) {
+                    int length = between(1, Math.toIntExact(md.length() - pos));
+                    byte[] buffer = new byte[length];
+                    in.readBytes(buffer, 0, length);
+                    target.writeFileChunk(md, pos, new BytesArray(buffer), pos + length == md.length(), 0, mock(ActionListener.class));
+                    pos += length;
+                }
+            }
+        }
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/index/shard/RestoreOnlyRepository.java b/test/framework/src/main/java/org/opensearch/index/shard/RestoreOnlyRepository.java
index 5ed85fedc8cea..7e25ed97a7ea1 100644
--- a/test/framework/src/main/java/org/opensearch/index/shard/RestoreOnlyRepository.java
+++ b/test/framework/src/main/java/org/opensearch/index/shard/RestoreOnlyRepository.java
@@ -33,17 +33,19 @@
 
 import org.apache.lucene.index.IndexCommit;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateUpdateTask;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.component.AbstractLifecycleComponent;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.index.snapshots.IndexShardSnapshotStatus;
 import org.opensearch.index.store.Store;
+import org.opensearch.index.store.lockmanager.RemoteStoreLockManagerFactory;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.IndexMetaDataGenerations;
 import org.opensearch.repositories.Repository;
@@ -152,6 +154,16 @@ public long getRestoreThrottleTimeInNanos() {
         return 0;
     }
 
+    @Override
+    public long getRemoteUploadThrottleTimeInNanos() {
+        return 0;
+    }
+
+    @Override
+    public long getRemoteDownloadThrottleTimeInNanos() {
+        return 0;
+    }
+
     @Override
     public String startVerification() {
         return null;
@@ -165,6 +177,11 @@ public boolean isReadOnly() {
         return false;
     }
 
+    @Override
+    public boolean isSystemRepository() {
+        return false;
+    }
+
     @Override
     public void snapshotShard(
         Store store,
@@ -209,4 +226,16 @@ public void cloneShardSnapshot(
     ) {
         throw new UnsupportedOperationException("Unsupported for restore-only repository");
     }
+
+    @Override
+    public void cloneRemoteStoreIndexShardSnapshot(
+        SnapshotId source,
+        SnapshotId target,
+        RepositoryShardId shardId,
+        String shardGeneration,
+        RemoteStoreLockManagerFactory remoteStoreLockManagerFactory,
+        ActionListener<String> listener
+    ) {
+        throw new UnsupportedOperationException("Unsupported for restore-only repository");
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/indices/analysis/AnalysisFactoryTestCase.java b/test/framework/src/main/java/org/opensearch/indices/analysis/AnalysisFactoryTestCase.java
index fd762289caddb..c412ae8317f24 100644
--- a/test/framework/src/main/java/org/opensearch/indices/analysis/AnalysisFactoryTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/indices/analysis/AnalysisFactoryTestCase.java
@@ -98,6 +98,7 @@ public abstract class AnalysisFactoryTestCase extends OpenSearchTestCase {
         .put("czechstem", MovedToAnalysisCommon.class)
         .put("decimaldigit", MovedToAnalysisCommon.class)
         .put("delimitedpayload", MovedToAnalysisCommon.class)
+        .put("delimitedtermfrequency", MovedToAnalysisCommon.class)
         .put("dictionarycompoundword", MovedToAnalysisCommon.class)
         .put("edgengram", MovedToAnalysisCommon.class)
         .put("elision", MovedToAnalysisCommon.class)
@@ -201,9 +202,6 @@ public abstract class AnalysisFactoryTestCase extends OpenSearchTestCase {
         .put("daterecognizer", Void.class)
         // for token filters that generate bad offsets, which are now rejected since Lucene 7
         .put("fixbrokenoffsets", Void.class)
-        // should we expose it, or maybe think about higher level integration of the
-        // fake term frequency feature (LUCENE-7854)
-        .put("delimitedtermfrequency", Void.class)
         // LUCENE-8273: ProtectedTermFilterFactory allows analysis chains to skip
         // particular token filters based on the attributes of the current token.
         .put("protectedterm", Void.class)
@@ -221,6 +219,9 @@ public abstract class AnalysisFactoryTestCase extends OpenSearchTestCase {
         .put("spanishpluralstem", Void.class)
         // LUCENE-10352
         .put("daitchmokotoffsoundex", Void.class)
+        .put("persianstem", Void.class)
+        // https://github.com/apache/lucene/pull/12169
+        .put("word2vecsynonym", Void.class)
         .immutableMap();
 
     static final Map<String, Class<?>> KNOWN_CHARFILTERS = new MapBuilder<String, Class<?>>()
diff --git a/test/framework/src/main/java/org/opensearch/indices/recovery/AsyncRecoveryTarget.java b/test/framework/src/main/java/org/opensearch/indices/recovery/AsyncRecoveryTarget.java
index b3ddec889c1e2..a89c83b7c1dc3 100644
--- a/test/framework/src/main/java/org/opensearch/indices/recovery/AsyncRecoveryTarget.java
+++ b/test/framework/src/main/java/org/opensearch/indices/recovery/AsyncRecoveryTarget.java
@@ -33,17 +33,20 @@
 package org.opensearch.indices.recovery;
 
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.index.seqno.ReplicationTracker;
 import org.opensearch.index.seqno.RetentionLeases;
+import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.index.translog.Translog;
+import org.opensearch.indices.replication.SegmentReplicationTarget;
 
 import java.util.List;
 import java.util.concurrent.Executor;
+import java.util.function.Function;
 
 /**
  * Wraps a {@link RecoveryTarget} to make all remote calls to be executed asynchronously using the provided {@code executor}.
@@ -52,9 +55,32 @@ public class AsyncRecoveryTarget implements RecoveryTargetHandler {
     private final RecoveryTargetHandler target;
     private final Executor executor;
 
+    private final IndexShard primary;
+
+    private final IndexShard replica;
+
+    private final Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction;
+
     public AsyncRecoveryTarget(RecoveryTargetHandler target, Executor executor) {
         this.executor = executor;
         this.target = target;
+        this.primary = null;
+        this.replica = null;
+        this.replicatePrimaryFunction = (a) -> null;
+    }
+
+    public AsyncRecoveryTarget(
+        RecoveryTargetHandler target,
+        Executor executor,
+        IndexShard primary,
+        IndexShard replica,
+        Function<List<IndexShard>, List<SegmentReplicationTarget>> replicatePrimaryFunction
+    ) {
+        this.executor = executor;
+        this.target = target;
+        this.primary = primary;
+        this.replica = replica;
+        this.replicatePrimaryFunction = replicatePrimaryFunction;
     }
 
     @Override
@@ -62,6 +88,11 @@ public void prepareForTranslogOperations(int totalTranslogOps, ActionListener<Vo
         executor.execute(() -> target.prepareForTranslogOperations(totalTranslogOps, listener));
     }
 
+    @Override
+    public void forceSegmentFileSync() {
+        this.replicatePrimaryFunction.apply(List.of(primary, replica));
+    }
+
     @Override
     public void finalizeRecovery(long globalCheckpoint, long trimAboveSeqNo, ActionListener<Void> listener) {
         executor.execute(() -> target.finalizeRecovery(globalCheckpoint, trimAboveSeqNo, listener));
diff --git a/test/framework/src/main/java/org/opensearch/indices/recovery/DefaultRecoverySettings.java b/test/framework/src/main/java/org/opensearch/indices/recovery/DefaultRecoverySettings.java
new file mode 100644
index 0000000000000..359668f5dad71
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/indices/recovery/DefaultRecoverySettings.java
@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.recovery;
+
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Settings;
+
+/**
+ * Utility to provide a {@link RecoverySettings} instance containing all defaults
+ */
+public final class DefaultRecoverySettings {
+    private DefaultRecoverySettings() {}
+
+    public static final RecoverySettings INSTANCE = new RecoverySettings(
+        Settings.EMPTY,
+        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS)
+    );
+}
diff --git a/test/framework/src/main/java/org/opensearch/ingest/IngestTestPlugin.java b/test/framework/src/main/java/org/opensearch/ingest/IngestTestPlugin.java
index 86918939acfff..f7e1ca116853f 100644
--- a/test/framework/src/main/java/org/opensearch/ingest/IngestTestPlugin.java
+++ b/test/framework/src/main/java/org/opensearch/ingest/IngestTestPlugin.java
@@ -32,12 +32,12 @@
 
 package org.opensearch.ingest;
 
-import java.util.Collections;
-import java.util.Map;
-
 import org.opensearch.plugins.IngestPlugin;
 import org.opensearch.plugins.Plugin;
 
+import java.util.Collections;
+import java.util.Map;
+
 /**
  * Adds an ingest processor to be used in tests.
  */
diff --git a/test/framework/src/main/java/org/opensearch/ingest/RandomDocumentPicks.java b/test/framework/src/main/java/org/opensearch/ingest/RandomDocumentPicks.java
index 5d55f098a1f82..c478bf9239f74 100644
--- a/test/framework/src/main/java/org/opensearch/ingest/RandomDocumentPicks.java
+++ b/test/framework/src/main/java/org/opensearch/ingest/RandomDocumentPicks.java
@@ -35,6 +35,7 @@
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.opensearch.index.VersionType;
 
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/mockito/plugin/PriviledgedMockMaker.java b/test/framework/src/main/java/org/opensearch/mockito/plugin/PriviledgedMockMaker.java
index 7eb8ec90b9071..ef13e065968df 100644
--- a/test/framework/src/main/java/org/opensearch/mockito/plugin/PriviledgedMockMaker.java
+++ b/test/framework/src/main/java/org/opensearch/mockito/plugin/PriviledgedMockMaker.java
@@ -8,13 +8,6 @@
 
 package org.opensearch.mockito.plugin;
 
-import org.mockito.Incubating;
-import org.mockito.MockedConstruction;
-import org.mockito.internal.creation.bytebuddy.ByteBuddyMockMaker;
-import org.mockito.internal.util.reflection.LenientCopyTool;
-import org.mockito.invocation.MockHandler;
-import org.mockito.mock.MockCreationSettings;
-import org.mockito.plugins.MockMaker;
 import org.opensearch.common.SuppressForbidden;
 
 import java.security.AccessControlContext;
@@ -26,6 +19,14 @@
 import java.util.Optional;
 import java.util.function.Function;
 
+import org.mockito.Incubating;
+import org.mockito.MockedConstruction;
+import org.mockito.internal.creation.bytebuddy.ByteBuddyMockMaker;
+import org.mockito.internal.util.reflection.LenientCopyTool;
+import org.mockito.invocation.MockHandler;
+import org.mockito.mock.MockCreationSettings;
+import org.mockito.plugins.MockMaker;
+
 /**
  * Mockito plugin which wraps the Mockito calls into priviledged execution blocks and respects
  * SecurityManager presence.
diff --git a/test/framework/src/main/java/org/opensearch/node/MockNode.java b/test/framework/src/main/java/org/opensearch/node/MockNode.java
index 1bb034588d20e..e6c7e21d5b3ea 100644
--- a/test/framework/src/main/java/org/opensearch/node/MockNode.java
+++ b/test/framework/src/main/java/org/opensearch/node/MockNode.java
@@ -37,19 +37,19 @@
 import org.opensearch.cluster.MockInternalClusterInfoService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.PageCacheRecycler;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.env.Environment;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptService;
@@ -60,6 +60,7 @@
 import org.opensearch.search.SearchService;
 import org.opensearch.search.fetch.FetchPhase;
 import org.opensearch.search.query.QueryPhase;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.test.MockHttpTransport;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
@@ -178,7 +179,8 @@ protected SearchService newSearchService(
             bigArrays,
             queryPhase,
             fetchPhase,
-            circuitBreakerService
+            circuitBreakerService,
+            indexSearcherExecutor
         );
     }
 
@@ -198,16 +200,35 @@ protected TransportService newTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
         // we use the MockTransportService.TestPlugin class as a marker to create a network
         // module with this MockNetworkService. NetworkService is such an integral part of the systme
         // we don't allow to plug it in from plugins or anything. this is a test-only override and
         // can't be done in a production env.
         if (getPluginsService().filterPlugins(MockTransportService.TestPlugin.class).isEmpty()) {
-            return super.newTransportService(settings, transport, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders);
+            return super.newTransportService(
+                settings,
+                transport,
+                threadPool,
+                interceptor,
+                localNodeFactory,
+                clusterSettings,
+                taskHeaders,
+                tracer
+            );
         } else {
-            return new MockTransportService(settings, transport, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders);
+            return new MockTransportService(
+                settings,
+                transport,
+                threadPool,
+                interceptor,
+                localNodeFactory,
+                clusterSettings,
+                taskHeaders,
+                tracer
+            );
         }
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/node/RecoverySettingsChunkSizePlugin.java b/test/framework/src/main/java/org/opensearch/node/RecoverySettingsChunkSizePlugin.java
index 062675737f277..dabf23ce08263 100644
--- a/test/framework/src/main/java/org/opensearch/node/RecoverySettingsChunkSizePlugin.java
+++ b/test/framework/src/main/java/org/opensearch/node/RecoverySettingsChunkSizePlugin.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.Plugin;
 
diff --git a/test/framework/src/main/java/org/opensearch/repositories/AbstractThirdPartyRepositoryTestCase.java b/test/framework/src/main/java/org/opensearch/repositories/AbstractThirdPartyRepositoryTestCase.java
index 8ddaba8067b2d..5c28d9f83a4ee 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/AbstractThirdPartyRepositoryTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/AbstractThirdPartyRepositoryTestCase.java
@@ -36,13 +36,13 @@
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.blobstore.support.PlainBlobMetadata;
 import org.opensearch.common.settings.SecureSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.blobstore.BlobStoreTestUtil;
 import org.opensearch.snapshots.SnapshotState;
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/AbstractBlobContainerRetriesTestCase.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/AbstractBlobContainerRetriesTestCase.java
index d7b057e5479eb..8a4797e7cf309 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/blobstore/AbstractBlobContainerRetriesTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/AbstractBlobContainerRetriesTestCase.java
@@ -34,17 +34,18 @@
 
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.ConnectionClosedException;
 import org.apache.http.HttpStatus;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.blobstore.BlobContainer;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.Streams;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.CountDown;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
@@ -58,8 +59,6 @@
 import java.util.Arrays;
 import java.util.Locale;
 import java.util.Optional;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicLong;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -409,85 +408,4 @@ protected void sendIncompleteContent(HttpExchange exchange, byte[] bytes) throws
             exchange.getResponseBody().flush();
         }
     }
-
-    /**
-     * A resettable InputStream that only serves zeros.
-     **/
-    public static class ZeroInputStream extends InputStream {
-
-        private final AtomicBoolean closed = new AtomicBoolean(false);
-        private final long length;
-        private final AtomicLong reads;
-        private volatile long mark;
-
-        public ZeroInputStream(final long length) {
-            this.length = length;
-            this.reads = new AtomicLong(0);
-            this.mark = -1;
-        }
-
-        @Override
-        public int read() throws IOException {
-            ensureOpen();
-            return (reads.incrementAndGet() <= length) ? 0 : -1;
-        }
-
-        @Override
-        public int read(byte[] b, int off, int len) throws IOException {
-            ensureOpen();
-            if (len == 0) {
-                return 0;
-            }
-
-            final int available = available();
-            if (available == 0) {
-                return -1;
-            }
-
-            final int toCopy = Math.min(len, available);
-            Arrays.fill(b, off, off + toCopy, (byte) 0);
-            reads.addAndGet(toCopy);
-            return toCopy;
-        }
-
-        @Override
-        public boolean markSupported() {
-            return true;
-        }
-
-        @Override
-        public synchronized void mark(int readlimit) {
-            mark = reads.get();
-        }
-
-        @Override
-        public synchronized void reset() throws IOException {
-            ensureOpen();
-            reads.set(mark);
-        }
-
-        @Override
-        public int available() throws IOException {
-            ensureOpen();
-            if (reads.get() >= length) {
-                return 0;
-            }
-            try {
-                return Math.toIntExact(length - reads.get());
-            } catch (ArithmeticException e) {
-                return Integer.MAX_VALUE;
-            }
-        }
-
-        @Override
-        public void close() {
-            closed.set(true);
-        }
-
-        private void ensureOpen() throws IOException {
-            if (closed.get()) {
-                throw new IOException("Stream closed");
-            }
-        }
-    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/BlobStoreTestUtil.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/BlobStoreTestUtil.java
index ad61153b62a06..22801e39d54f8 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/blobstore/BlobStoreTestUtil.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/BlobStoreTestUtil.java
@@ -47,22 +47,24 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterApplierService;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.index.IndexModule;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.RepositoryData;
 import org.opensearch.repositories.ShardGenerations;
 import org.opensearch.snapshots.SnapshotId;
 import org.opensearch.snapshots.SnapshotInfo;
+import org.opensearch.snapshots.SnapshotMissingException;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.threadpool.ThreadPool;
 
@@ -88,6 +90,7 @@
 
 import static org.opensearch.test.OpenSearchTestCase.buildNewFakeTransportAddress;
 import static org.opensearch.test.OpenSearchTestCase.randomIntBetween;
+import static org.hamcrest.Matchers.anEmptyMap;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.hasKey;
@@ -105,7 +108,7 @@
 public final class BlobStoreTestUtil {
 
     public static void assertRepoConsistency(InternalTestCluster testCluster, String repoName) {
-        final BlobStoreRepository repo = (BlobStoreRepository) testCluster.getCurrentMasterNodeInstance(RepositoriesService.class)
+        final BlobStoreRepository repo = (BlobStoreRepository) testCluster.getCurrentClusterManagerNodeInstance(RepositoriesService.class)
             .repository(repoName);
         BlobStoreTestUtil.assertConsistency(repo, repo.threadPool().executor(ThreadPool.Names.GENERIC));
     }
@@ -133,14 +136,14 @@ public static void assertConsistency(BlobStoreRepository repository, Executor ex
                 final RepositoryData repositoryData;
                 try (
                     InputStream blob = blobContainer.readBlob(BlobStoreRepository.INDEX_FILE_PREFIX + latestGen);
-                    XContentParser parser = XContentType.JSON.xContent()
+                    XContentParser parser = MediaTypeRegistry.JSON.xContent()
                         .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, blob)
                 ) {
                     repositoryData = RepositoryData.snapshotsFromXContent(parser, latestGen, false);
                 }
                 assertIndexUUIDs(repository, repositoryData);
                 assertSnapshotUUIDs(repository, repositoryData);
-                assertShardIndexGenerations(blobContainer, repositoryData.shardGenerations());
+                assertShardIndexGenerations(repository, blobContainer, repositoryData);
                 return null;
             } catch (AssertionError e) {
                 return e;
@@ -164,23 +167,31 @@ private static void assertIndexGenerations(BlobContainer repoRoot, long latestGe
         assertTrue(indexGenerations.length <= 2);
     }
 
-    private static void assertShardIndexGenerations(BlobContainer repoRoot, ShardGenerations shardGenerations) throws IOException {
+    private static void assertShardIndexGenerations(BlobStoreRepository repository, BlobContainer repoRoot, RepositoryData repositoryData)
+        throws IOException {
+        final ShardGenerations shardGenerations = repositoryData.shardGenerations();
         final BlobContainer indicesContainer = repoRoot.children().get("indices");
         for (IndexId index : shardGenerations.indices()) {
             final List<String> gens = shardGenerations.getGens(index);
             if (gens.isEmpty() == false) {
                 final BlobContainer indexContainer = indicesContainer.children().get(index.getId());
                 final Map<String, BlobContainer> shardContainers = indexContainer.children();
-                for (int i = 0; i < gens.size(); i++) {
-                    final String generation = gens.get(i);
-                    assertThat(generation, not(ShardGenerations.DELETED_SHARD_GEN));
-                    if (generation != null && generation.equals(ShardGenerations.NEW_SHARD_GEN) == false) {
-                        final String shardId = Integer.toString(i);
-                        assertThat(shardContainers, hasKey(shardId));
-                        assertThat(
-                            shardContainers.get(shardId).listBlobsByPrefix(BlobStoreRepository.INDEX_FILE_PREFIX),
-                            hasKey(BlobStoreRepository.INDEX_FILE_PREFIX + generation)
-                        );
+                if (isRemoteSnapshot(repository, repositoryData, index)) {
+                    // If the source of the data is another snapshot (i.e. searchable snapshot)
+                    // then assert that there is no shard data (because it exists in the source snapshot)
+                    assertThat(shardContainers, anEmptyMap());
+                } else {
+                    for (int i = 0; i < gens.size(); i++) {
+                        final String generation = gens.get(i);
+                        assertThat(generation, not(ShardGenerations.DELETED_SHARD_GEN));
+                        if (generation != null && generation.equals(ShardGenerations.NEW_SHARD_GEN) == false) {
+                            final String shardId = Integer.toString(i);
+                            assertThat(shardContainers, hasKey(shardId));
+                            assertThat(
+                                shardContainers.get(shardId).listBlobsByPrefix(BlobStoreRepository.INDEX_FILE_PREFIX),
+                                hasKey(BlobStoreRepository.INDEX_FILE_PREFIX + generation)
+                            );
+                        }
                     }
                 }
             }
@@ -229,15 +240,18 @@ private static void assertSnapshotUUIDs(BlobStoreRepository repository, Reposito
         final BlobContainer repoRoot = repository.blobContainer();
         final Collection<SnapshotId> snapshotIds = repositoryData.getSnapshotIds();
         final List<String> expectedSnapshotUUIDs = snapshotIds.stream().map(SnapshotId::getUUID).collect(Collectors.toList());
-        for (String prefix : new String[] { BlobStoreRepository.SNAPSHOT_PREFIX, BlobStoreRepository.METADATA_PREFIX }) {
-            final Collection<String> foundSnapshotUUIDs = repoRoot.listBlobs()
-                .keySet()
-                .stream()
-                .filter(p -> p.startsWith(prefix))
-                .map(p -> p.replace(prefix, "").replace(".dat", ""))
-                .collect(Collectors.toSet());
-            assertThat(foundSnapshotUUIDs, containsInAnyOrder(expectedSnapshotUUIDs.toArray(Strings.EMPTY_ARRAY)));
+        Collection<String> foundSnapshotUUIDs = new HashSet<>();
+        for (String prefix : new String[] { BlobStoreRepository.SNAPSHOT_PREFIX, BlobStoreRepository.SHALLOW_SNAPSHOT_PREFIX }) {
+            foundSnapshotUUIDs.addAll(
+                repoRoot.listBlobs()
+                    .keySet()
+                    .stream()
+                    .filter(p -> p.startsWith(prefix))
+                    .map(p -> p.replace(prefix, "").replace(".dat", ""))
+                    .collect(Collectors.toSet())
+            );
         }
+        assertThat(foundSnapshotUUIDs, containsInAnyOrder(expectedSnapshotUUIDs.toArray(Strings.EMPTY_ARRAY)));
 
         final BlobContainer indicesContainer = repository.getBlobContainer().children().get("indices");
         final Map<String, BlobContainer> indices;
@@ -292,10 +306,16 @@ private static void assertSnapshotUUIDs(BlobStoreRepository repository, Reposito
                             .stream()
                             .noneMatch(shardFailure -> shardFailure.index().equals(index) && shardFailure.shardId() == shardId)) {
                         final Map<String, BlobMetadata> shardPathContents = shardContainer.listBlobs();
-                        assertThat(
-                            shardPathContents,
-                            hasKey(String.format(Locale.ROOT, BlobStoreRepository.SNAPSHOT_NAME_FORMAT, snapshotId.getUUID()))
+
+                        assertTrue(
+                            shardPathContents.containsKey(
+                                String.format(Locale.ROOT, BlobStoreRepository.SHALLOW_SNAPSHOT_NAME_FORMAT, snapshotId.getUUID())
+                            )
+                                || shardPathContents.containsKey(
+                                    String.format(Locale.ROOT, BlobStoreRepository.SNAPSHOT_NAME_FORMAT, snapshotId.getUUID())
+                                )
                         );
+
                         assertThat(
                             shardPathContents.keySet()
                                 .stream()
@@ -410,11 +430,13 @@ private static ClusterService mockClusterService(ClusterState initialState) {
         final ClusterService clusterService = mock(ClusterService.class);
         final ClusterApplierService clusterApplierService = mock(ClusterApplierService.class);
         when(clusterService.getClusterApplierService()).thenReturn(clusterApplierService);
-        // Setting local node as master so it may update the repository metadata in the cluster state
+        // Setting local node as cluster-manager so it may update the repository metadata in the cluster state
         final DiscoveryNode localNode = new DiscoveryNode("", buildNewFakeTransportAddress(), Version.CURRENT);
         final AtomicReference<ClusterState> currentState = new AtomicReference<>(
             ClusterState.builder(initialState)
-                .nodes(DiscoveryNodes.builder().add(localNode).masterNodeId(localNode.getId()).localNodeId(localNode.getId()).build())
+                .nodes(
+                    DiscoveryNodes.builder().add(localNode).clusterManagerNodeId(localNode.getId()).localNodeId(localNode.getId()).build()
+                )
                 .build()
         );
         when(clusterService.state()).then(invocationOnMock -> currentState.get());
@@ -437,4 +459,24 @@ private static ClusterService mockClusterService(ClusterState initialState) {
         when(clusterApplierService.threadPool()).thenReturn(threadPool);
         return clusterService;
     }
+
+    private static boolean isRemoteSnapshot(BlobStoreRepository repository, RepositoryData repositoryData, IndexId indexId)
+        throws IOException {
+        final Collection<SnapshotId> snapshotIds = repositoryData.getSnapshotIds();
+        for (SnapshotId snapshotId : snapshotIds) {
+            try {
+                if (isRemoteSnapshot(repository.getSnapshotIndexMetaData(repositoryData, snapshotId, indexId))) {
+                    return true;
+                }
+            } catch (SnapshotMissingException e) {
+                // Index does not exist in this snapshot so continue looping
+            }
+        }
+        return false;
+    }
+
+    private static boolean isRemoteSnapshot(IndexMetadata metadata) {
+        final String storeType = metadata.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey());
+        return storeType != null && storeType.equals(IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey());
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
index 7d9810a11e143..507a100c94e0d 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
@@ -33,7 +33,6 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequestBuilder;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
@@ -42,14 +41,16 @@
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.Client;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.Streams;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.compress.CompressorRegistry;
 import org.opensearch.repositories.IndexId;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
@@ -92,7 +93,13 @@ public static RepositoryData getRepositoryData(Repository repository) {
     protected abstract String repositoryType();
 
     protected Settings repositorySettings() {
-        return Settings.builder().put("compress", randomBoolean()).build();
+        final boolean compress = randomBoolean();
+        final Settings.Builder builder = Settings.builder();
+        builder.put("compress", compress);
+        if (compress) {
+            builder.put("compression_type", randomFrom(CompressorRegistry.registeredCompressors().keySet()));
+        }
+        return builder.build();
     }
 
     protected final String createRepository(final String name) {
@@ -107,7 +114,7 @@ protected final String createRepository(final String name, final Settings settin
             client().admin().cluster().preparePutRepository(name).setType(repositoryType()).setVerify(verify).setSettings(settings)
         );
 
-        internalCluster().getDataOrMasterNodeInstances(RepositoriesService.class).forEach(repositories -> {
+        internalCluster().getDataOrClusterManagerNodeInstances(RepositoriesService.class).forEach(repositories -> {
             assertThat(repositories.repository(name), notNullValue());
             assertThat(repositories.repository(name), instanceOf(BlobStoreRepository.class));
             assertThat(repositories.repository(name).isReadOnly(), is(false));
@@ -158,6 +165,27 @@ public void testWriteRead() throws IOException {
         }
     }
 
+    public void testReadRange() throws IOException {
+        try (BlobStore store = newBlobStore()) {
+            final BlobContainer container = store.blobContainer(new BlobPath());
+            final byte[] data = randomBytes(4096);
+
+            // Pick a subrange starting somewhere between position 100 and 1000
+            // and ending somewhere between 100 bytes past that position and
+            // 100 bytes before the end
+            final int startOffset = randomIntBetween(100, 1000);
+            final int endOffset = randomIntBetween(startOffset + 100, data.length - 100);
+            final byte[] subrangeData = Arrays.copyOfRange(data, startOffset, endOffset);
+
+            writeBlob(container, "foobar", new BytesArray(data), randomBoolean());
+            try (InputStream stream = container.readBlob("foobar", startOffset, subrangeData.length)) {
+                final byte[] actual = stream.readAllBytes();
+                assertArrayEquals(subrangeData, actual);
+            }
+            container.delete();
+        }
+    }
+
     public void testList() throws IOException {
         try (BlobStore store = newBlobStore()) {
             final BlobContainer container = store.blobContainer(new BlobPath());
@@ -280,7 +308,7 @@ protected static void writeBlob(BlobContainer container, String blobName, BytesA
 
     protected BlobStore newBlobStore() {
         final String repository = createRepository(randomName());
-        final BlobStoreRepository blobStoreRepository = (BlobStoreRepository) internalCluster().getMasterNodeInstance(
+        final BlobStoreRepository blobStoreRepository = (BlobStoreRepository) internalCluster().getClusterManagerNodeInstance(
             RepositoriesService.class
         ).repository(repository);
         return PlainActionFuture.get(
@@ -470,8 +498,11 @@ public void testIndicesDeletedFromRepository() throws Exception {
         assertAcked(client().admin().cluster().prepareDeleteSnapshot(repoName, "test-snap").get());
 
         logger.info("--> verify index folder deleted from blob container");
-        RepositoriesService repositoriesSvc = internalCluster().getInstance(RepositoriesService.class, internalCluster().getMasterName());
-        ThreadPool threadPool = internalCluster().getInstance(ThreadPool.class, internalCluster().getMasterName());
+        RepositoriesService repositoriesSvc = internalCluster().getInstance(
+            RepositoriesService.class,
+            internalCluster().getClusterManagerName()
+        );
+        ThreadPool threadPool = internalCluster().getInstance(ThreadPool.class, internalCluster().getClusterManagerName());
         BlobStoreRepository repository = (BlobStoreRepository) repositoriesSvc.repository(repoName);
 
         final SetOnce<BlobContainer> indicesBlobContainer = new SetOnce<>();
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchMockAPIBasedRepositoryIntegTestCase.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchMockAPIBasedRepositoryIntegTestCase.java
index f082c7a45a207..9ced3f960f02f 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchMockAPIBasedRepositoryIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchMockAPIBasedRepositoryIntegTestCase.java
@@ -35,6 +35,7 @@
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+
 import org.apache.http.HttpStatus;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -42,11 +43,11 @@
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.action.admin.indices.forcemerge.ForceMergeResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.network.InetAddresses;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
 import org.opensearch.repositories.RepositoryMissingException;
@@ -358,7 +359,7 @@ public HttpHandler getDelegate() {
         }
 
         synchronized Map<String, Long> getOperationsCount() {
-            return org.opensearch.common.collect.Map.copyOf(operationCount);
+            return Map.copyOf(operationCount);
         }
 
         protected synchronized void trackRequest(final String requestType) {
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/ZeroInputStream.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/ZeroInputStream.java
new file mode 100644
index 0000000000000..f299c17f16a06
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/ZeroInputStream.java
@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.repositories.blobstore;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * A resettable InputStream that only serves zeros.
+ **/
+public class ZeroInputStream extends InputStream {
+
+    private final AtomicBoolean closed = new AtomicBoolean(false);
+    private final long length;
+    private final AtomicLong reads;
+    private volatile long mark;
+
+    public ZeroInputStream(final long length) {
+        this.length = length;
+        this.reads = new AtomicLong(0);
+        this.mark = -1;
+    }
+
+    @Override
+    public int read() throws IOException {
+        ensureOpen();
+        return (reads.incrementAndGet() <= length) ? 0 : -1;
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        ensureOpen();
+        if (len == 0) {
+            return 0;
+        }
+
+        final int available = available();
+        if (available == 0) {
+            return -1;
+        }
+
+        final int toCopy = Math.min(len, available);
+        Arrays.fill(b, off, off + toCopy, (byte) 0);
+        reads.addAndGet(toCopy);
+        return toCopy;
+    }
+
+    @Override
+    public boolean markSupported() {
+        return true;
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        mark = reads.get();
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        ensureOpen();
+        reads.set(mark);
+    }
+
+    @Override
+    public int available() throws IOException {
+        ensureOpen();
+        if (reads.get() >= length) {
+            return 0;
+        }
+        try {
+            return Math.toIntExact(length - reads.get());
+        } catch (ArithmeticException e) {
+            return Integer.MAX_VALUE;
+        }
+    }
+
+    @Override
+    public void close() {
+        closed.set(true);
+    }
+
+    private void ensureOpen() throws IOException {
+        if (closed.get()) {
+            throw new IOException("Stream closed");
+        }
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/script/MockScriptEngine.java b/test/framework/src/main/java/org/opensearch/script/MockScriptEngine.java
index 9f8abdf5f2c8a..cb0614ddeb808 100644
--- a/test/framework/src/main/java/org/opensearch/script/MockScriptEngine.java
+++ b/test/framework/src/main/java/org/opensearch/script/MockScriptEngine.java
@@ -33,6 +33,7 @@
 package org.opensearch.script;
 
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Scorable;
 import org.opensearch.index.query.IntervalFilterScript;
 import org.opensearch.index.similarity.ScriptedSimilarity.Doc;
@@ -177,6 +178,14 @@ public void execute(Map<String, Object> ctx) {
                 }
             };
             return context.factoryClazz.cast(factory);
+        } else if (context.instanceClazz.equals(SearchScript.class)) {
+            SearchScript.Factory factory = parameters -> new SearchScript(parameters) {
+                @Override
+                public void execute(Map<String, Object> ctx) {
+                    script.apply(ctx);
+                }
+            };
+            return context.factoryClazz.cast(factory);
         } else if (context.instanceClazz.equals(AggregationScript.class)) {
             return context.factoryClazz.cast(new MockAggregationScript(script));
         } else if (context.instanceClazz.equals(IngestConditionalScript.class)) {
@@ -616,7 +625,7 @@ public MockScoreScript(MockDeterministicScript script) {
         }
 
         @Override
-        public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+        public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup, IndexSearcher indexSearcher) {
             return new ScoreScript.LeafFactory() {
                 @Override
                 public boolean needs_score() {
@@ -626,7 +635,7 @@ public boolean needs_score() {
                 @Override
                 public ScoreScript newInstance(LeafReaderContext ctx) throws IOException {
                     Scorable[] scorerHolder = new Scorable[1];
-                    return new ScoreScript(params, lookup, ctx) {
+                    return new ScoreScript(params, lookup, indexSearcher, ctx) {
                         @Override
                         public double execute(ExplanationHolder explanation) {
                             Map<String, Object> vars = new HashMap<>(getParams());
diff --git a/test/framework/src/main/java/org/opensearch/script/MockScriptService.java b/test/framework/src/main/java/org/opensearch/script/MockScriptService.java
index e4887255d0b9f..dff71189eb4ee 100644
--- a/test/framework/src/main/java/org/opensearch/script/MockScriptService.java
+++ b/test/framework/src/main/java/org/opensearch/script/MockScriptService.java
@@ -34,7 +34,6 @@
 
 import org.opensearch.common.settings.Settings;
 import org.opensearch.node.MockNode;
-
 import org.opensearch.plugins.Plugin;
 
 import java.util.Map;
@@ -79,14 +78,10 @@ public <FactoryType> FactoryType compile(
 
             @Override
             public Set<ScriptContext<?>> getSupportedContexts() {
-                return org.opensearch.common.collect.Set.of(context);
+                return Set.of(context);
             }
         };
-        return new MockScriptService(
-            Settings.EMPTY,
-            org.opensearch.common.collect.Map.of("lang", engine),
-            org.opensearch.common.collect.Map.of(context.name, context)
-        ) {
+        return new MockScriptService(Settings.EMPTY, Map.of("lang", engine), Map.of(context.name, context)) {
             @Override
             protected StoredScriptSource getScriptFromClusterState(String id) {
                 return storedLookup.get(id);
diff --git a/test/framework/src/main/java/org/opensearch/search/MockSearchService.java b/test/framework/src/main/java/org/opensearch/search/MockSearchService.java
index fd522cd298632..a0bbcb7be05f9 100644
--- a/test/framework/src/main/java/org/opensearch/search/MockSearchService.java
+++ b/test/framework/src/main/java/org/opensearch/search/MockSearchService.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.node.MockNode;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.ScriptService;
@@ -47,6 +47,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executor;
 import java.util.function.Consumer;
 
 public class MockSearchService extends SearchService {
@@ -94,7 +95,8 @@ public MockSearchService(
         BigArrays bigArrays,
         QueryPhase queryPhase,
         FetchPhase fetchPhase,
-        CircuitBreakerService circuitBreakerService
+        CircuitBreakerService circuitBreakerService,
+        Executor indexSearcherExecutor
     ) {
         super(
             clusterService,
@@ -106,7 +108,7 @@ public MockSearchService(
             fetchPhase,
             null,
             circuitBreakerService,
-            null
+            indexSearcherExecutor
         );
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/search/RandomSearchRequestGenerator.java b/test/framework/src/main/java/org/opensearch/search/RandomSearchRequestGenerator.java
index ec8545e583d33..b942136e1f1e2 100644
--- a/test/framework/src/main/java/org/opensearch/search/RandomSearchRequestGenerator.java
+++ b/test/framework/src/main/java/org/opensearch/search/RandomSearchRequestGenerator.java
@@ -35,15 +35,15 @@
 import org.opensearch.action.search.SearchRequest;
 import org.opensearch.action.search.SearchType;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.text.Text;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.QueryBuilders;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
@@ -65,6 +65,7 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.function.Supplier;
 
@@ -352,7 +353,7 @@ public static SearchSourceBuilder randomSearchSourceBuilder(
                 }
                 jsonBuilder.endArray();
                 jsonBuilder.endObject();
-                XContentParser parser = XContentFactory.xContent(XContentType.JSON)
+                XContentParser parser = MediaTypeRegistry.JSON.xContent()
                     .createParser(
                         NamedXContentRegistry.EMPTY,
                         DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -404,6 +405,9 @@ public static SearchSourceBuilder randomSearchSourceBuilder(
             }
             builder.pointInTimeBuilder(pit);
         }
+        if (randomBoolean()) {
+            builder.searchPipelineSource(new HashMap<>());
+        }
         return builder;
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/AggregatorTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/AggregatorTestCase.java
index 38a0253305833..5c649f1dc832d 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/AggregatorTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/AggregatorTestCase.java
@@ -39,15 +39,12 @@
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.document.StoredField;
-import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.apache.lucene.index.CompositeReaderContext;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexReaderContext;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.apache.lucene.sandbox.document.HalfFloatPoint;
-import org.apache.lucene.tests.search.AssertingIndexSearcher;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -57,14 +54,15 @@
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.AssertingDirectoryReader;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.search.AssertingIndexSearcher;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.NumericUtils;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.TriFunction;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
@@ -73,9 +71,14 @@
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.index.Index;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalysisRegistry;
 import org.opensearch.index.analysis.AnalyzerScope;
@@ -108,10 +111,7 @@
 import org.opensearch.index.mapper.TextFieldMapper;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesModule;
-import org.opensearch.indices.breaker.CircuitBreakerService;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.plugins.SearchPlugin;
@@ -132,8 +132,8 @@
 import org.opensearch.search.internal.ContextIndexSearcher;
 import org.opensearch.search.internal.SearchContext;
 import org.opensearch.search.lookup.SearchLookup;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalAggregationTestCase;
+import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 import org.junit.Before;
 
@@ -329,15 +329,17 @@ public boolean shouldCache(Query query) {
                 return false;
             }
         };
+        SearchContext searchContext = mock(SearchContext.class);
         ContextIndexSearcher contextIndexSearcher = new ContextIndexSearcher(
             indexSearcher.getIndexReader(),
             indexSearcher.getSimilarity(),
             queryCache,
             queryCachingPolicy,
-            false
+            false,
+            null,
+            searchContext
         );
 
-        SearchContext searchContext = mock(SearchContext.class);
         when(searchContext.numberOfShards()).thenReturn(1);
         when(searchContext.searcher()).thenReturn(contextIndexSearcher);
         when(searchContext.fetchPhase()).thenReturn(new FetchPhase(Arrays.asList(new FetchSourcePhase(), new FetchDocValuesPhase())));
@@ -347,6 +349,8 @@ public boolean shouldCache(Query query) {
         when(searchContext.indexShard()).thenReturn(indexShard);
         when(searchContext.aggregations()).thenReturn(new SearchContextAggregations(AggregatorFactories.EMPTY, bucketConsumer));
         when(searchContext.query()).thenReturn(query);
+        when(searchContext.bucketCollectorProcessor()).thenReturn(new BucketCollectorProcessor());
+        when(searchContext.asLocalBucketCountThresholds(any())).thenCallRealMethod();
         /*
          * Always use the circuit breaking big arrays instance so that the CircuitBreakerService
          * we're passed gets a chance to break.
@@ -1055,6 +1059,11 @@ public InternalAggregation buildEmptyAggregation() {
                         }
                     };
                 }
+
+                @Override
+                protected boolean supportsConcurrentSegmentSearch() {
+                    return true;
+                }
             };
         }
 
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/BaseAggregationTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/BaseAggregationTestCase.java
index 4237d52acaf6f..39209f037300c 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/BaseAggregationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/BaseAggregationTestCase.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.opensearch.test.AbstractBuilderTestCase;
 
@@ -67,7 +67,7 @@ public abstract class BaseAggregationTestCase<AB extends AbstractAggregationBuil
     public void testFromXContent() throws IOException {
         AB testAgg = createTestAggregatorBuilder();
         AggregatorFactories.Builder factoriesBuilder = AggregatorFactories.builder().addAggregator(testAgg);
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -91,7 +91,7 @@ public void testFromXContentMulti() throws IOException {
             factoriesBuilder.addAggregator(testAgg);
         }
 
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
@@ -138,8 +138,8 @@ public void testSerializationMulti() throws IOException {
      */
     public void testToString() throws IOException {
         AB testAgg = createTestAggregatorBuilder();
-        String toString = randomBoolean() ? Strings.toString(testAgg) : testAgg.toString();
-        XContentParser parser = createParser(XContentType.JSON.xContent(), toString);
+        String toString = randomBoolean() ? Strings.toString(MediaTypeRegistry.JSON, testAgg) : testAgg.toString();
+        XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), toString);
         AggregationBuilder newAgg = parse(parser);
         assertNotSame(newAgg, testAgg);
         assertEquals(testAgg, newAgg);
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/BasePipelineAggregationTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/BasePipelineAggregationTestCase.java
index 7660cf0ca8fce..2f589e80c22e2 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/BasePipelineAggregationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/BasePipelineAggregationTestCase.java
@@ -32,28 +32,18 @@
 
 package org.opensearch.search.aggregations;
 
-import static java.util.Collections.emptyList;
-import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
-import static org.hamcrest.Matchers.hasSize;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
-
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.plugins.SearchPlugin;
@@ -63,6 +53,16 @@
 import org.opensearch.test.AbstractQueryTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+import static java.util.Collections.emptyList;
+import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
+import static org.hamcrest.Matchers.hasSize;
+
 public abstract class BasePipelineAggregationTestCase<AF extends AbstractPipelineAggregationBuilder<AF>> extends OpenSearchTestCase {
 
     protected static final String STRING_FIELD_NAME = "mapped_string";
@@ -140,7 +140,7 @@ public void testFromXContent() throws IOException {
         AF testAgg = createTestAggregatorFactory();
         AggregatorFactories.Builder factoriesBuilder = AggregatorFactories.builder().addPipelineAggregator(testAgg);
         logger.info("Content string: {}", factoriesBuilder);
-        XContentBuilder builder = XContentFactory.contentBuilder(randomFrom(XContentType.values()));
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(randomFrom(XContentType.values()));
         if (randomBoolean()) {
             builder.prettyPrint();
         }
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/InternalSingleBucketAggregationTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/InternalSingleBucketAggregationTestCase.java
index 1816d87d98d28..f3d7c0910179b 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/InternalSingleBucketAggregationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/InternalSingleBucketAggregationTestCase.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.search.aggregations;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.rest.action.search.RestSearchAction;
 import org.opensearch.search.aggregations.bucket.InternalSingleBucketAggregation;
 import org.opensearch.search.aggregations.bucket.ParsedSingleBucketAggregation;
@@ -51,7 +51,7 @@
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;
 
 public abstract class InternalSingleBucketAggregationTestCase<T extends InternalSingleBucketAggregation> extends
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/bucket/AbstractTermsTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/bucket/AbstractTermsTestCase.java
index 75192e276982e..8e94f2cacf070 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/bucket/AbstractTermsTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/bucket/AbstractTermsTestCase.java
@@ -32,16 +32,41 @@
 
 package org.opensearch.search.aggregations.bucket;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.search.SearchResponse;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.opensearch.search.aggregations.bucket.terms.Terms;
 import org.opensearch.search.aggregations.bucket.terms.TermsAggregatorFactory.ExecutionMode;
-import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
+
+import java.util.Arrays;
+import java.util.Collection;
 
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.aggregations.AggregationBuilders.terms;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
 
-public abstract class AbstractTermsTestCase extends OpenSearchIntegTestCase {
+public abstract class AbstractTermsTestCase extends ParameterizedOpenSearchIntegTestCase {
+
+    public AbstractTermsTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
 
     public String randomExecutionHint() {
         return randomBoolean() ? null : randomFrom(ExecutionMode.values()).toString();
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/composite/BaseCompositeAggregatorTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/composite/BaseCompositeAggregatorTestCase.java
new file mode 100644
index 0000000000000..1b348dc7d41a7
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/composite/BaseCompositeAggregatorTestCase.java
@@ -0,0 +1,310 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.aggregations.composite;
+
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.DoublePoint;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.InetAddressPoint;
+import org.apache.lucene.document.IntPoint;
+import org.apache.lucene.document.LongPoint;
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.document.SortedSetDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.Sort;
+import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.SortedNumericSortField;
+import org.apache.lucene.search.SortedSetSortField;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.analysis.MockAnalyzer;
+import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.NumericUtils;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.time.DateFormatter;
+import org.opensearch.common.time.DateFormatters;
+import org.opensearch.core.common.text.Text;
+import org.opensearch.core.index.Index;
+import org.opensearch.index.IndexSettings;
+import org.opensearch.index.mapper.DateFieldMapper;
+import org.opensearch.index.mapper.DocumentMapper;
+import org.opensearch.index.mapper.IpFieldMapper;
+import org.opensearch.index.mapper.KeywordFieldMapper;
+import org.opensearch.index.mapper.MappedFieldType;
+import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.mapper.NumberFieldMapper;
+import org.opensearch.search.aggregations.AggregatorTestCase;
+import org.opensearch.search.aggregations.bucket.composite.CompositeAggregationBuilder;
+import org.opensearch.search.aggregations.bucket.composite.CompositeValuesSourceBuilder;
+import org.opensearch.search.aggregations.bucket.composite.InternalComposite;
+import org.opensearch.test.IndexSettingsModule;
+import org.junit.After;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Base class for the Aggregator Tests which are registered under Composite Aggregation.
+ */
+public class BaseCompositeAggregatorTestCase extends AggregatorTestCase {
+
+    protected static List<MappedFieldType> FIELD_TYPES;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        FIELD_TYPES = new ArrayList<>();
+        FIELD_TYPES.add(new KeywordFieldMapper.KeywordFieldType("keyword"));
+        FIELD_TYPES.add(new NumberFieldMapper.NumberFieldType("long", NumberFieldMapper.NumberType.LONG));
+        FIELD_TYPES.add(new NumberFieldMapper.NumberFieldType("double", NumberFieldMapper.NumberType.DOUBLE));
+        FIELD_TYPES.add(new DateFieldMapper.DateFieldType("date", DateFormatter.forPattern("yyyy-MM-dd||epoch_millis")));
+        FIELD_TYPES.add(new NumberFieldMapper.NumberFieldType("price", NumberFieldMapper.NumberType.INTEGER));
+        FIELD_TYPES.add(new KeywordFieldMapper.KeywordFieldType("terms"));
+        FIELD_TYPES.add(new IpFieldMapper.IpFieldType("ip"));
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        super.tearDown();
+        FIELD_TYPES = null;
+    }
+
+    @Override
+    protected MapperService mapperServiceMock() {
+        MapperService mapperService = mock(MapperService.class);
+        DocumentMapper mapper = mock(DocumentMapper.class);
+        when(mapper.typeText()).thenReturn(new Text("_doc"));
+        when(mapper.type()).thenReturn("_doc");
+        when(mapperService.documentMapper()).thenReturn(mapper);
+        return mapperService;
+    }
+
+    protected static Map<String, List<Object>> createDocument(Object... fields) {
+        assert fields.length % 2 == 0;
+        final Map<String, List<Object>> map = new HashMap<>();
+        for (int i = 0; i < fields.length; i += 2) {
+            String field = (String) fields[i];
+            if (fields[i + 1] instanceof List) {
+                map.put(field, (List<Object>) fields[i + 1]);
+            } else {
+                map.put(field, Collections.singletonList(fields[i + 1]));
+            }
+        }
+        return map;
+    }
+
+    protected void testSearchCase(
+        List<Query> queries,
+        List<Map<String, List<Object>>> dataset,
+        Supplier<CompositeAggregationBuilder> create,
+        Consumer<InternalComposite> verify
+    ) throws IOException {
+        for (Query query : queries) {
+            executeTestCase(false, false, query, dataset, create, verify);
+            executeTestCase(false, true, query, dataset, create, verify);
+        }
+    }
+
+    protected void executeTestCase(
+        boolean forceMerge,
+        boolean useIndexSort,
+        Query query,
+        List<Map<String, List<Object>>> dataset,
+        Supplier<CompositeAggregationBuilder> create,
+        Consumer<InternalComposite> verify
+    ) throws IOException {
+        Map<String, MappedFieldType> types = FIELD_TYPES.stream().collect(Collectors.toMap(MappedFieldType::name, Function.identity()));
+        CompositeAggregationBuilder aggregationBuilder = create.get();
+        Sort indexSort = useIndexSort ? buildIndexSort(aggregationBuilder.sources(), types) : null;
+        IndexSettings indexSettings = createIndexSettings(indexSort);
+        try (Directory directory = newDirectory()) {
+            IndexWriterConfig config = newIndexWriterConfig(random(), new MockAnalyzer(random()));
+            if (indexSort != null) {
+                config.setIndexSort(indexSort);
+                config.setCodec(TestUtil.getDefaultCodec());
+            }
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory, config)) {
+                Document document = new Document();
+                int id = 0;
+                for (Map<String, List<Object>> fields : dataset) {
+                    document.clear();
+                    addToDocument(id, document, fields);
+                    indexWriter.addDocument(document);
+                    id++;
+                }
+                if (forceMerge || rarely()) {
+                    // forceMerge randomly or if the collector-per-leaf testing stuff would break the tests.
+                    indexWriter.forceMerge(1);
+                } else {
+                    if (dataset.size() > 0) {
+                        int numDeletes = randomIntBetween(1, 25);
+                        for (int i = 0; i < numDeletes; i++) {
+                            id = randomIntBetween(0, dataset.size() - 1);
+                            indexWriter.deleteDocuments(new Term("id", Integer.toString(id)));
+                            document.clear();
+                            addToDocument(id, document, dataset.get(id));
+                            indexWriter.addDocument(document);
+                        }
+                    }
+
+                }
+            }
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                IndexSearcher indexSearcher = new IndexSearcher(indexReader);
+                InternalComposite composite = searchAndReduce(
+                    indexSettings,
+                    indexSearcher,
+                    query,
+                    aggregationBuilder,
+                    FIELD_TYPES.toArray(new MappedFieldType[0])
+                );
+                verify.accept(composite);
+            }
+        }
+    }
+
+    protected void addToDocument(int id, Document doc, Map<String, List<Object>> keys) {
+        doc.add(new StringField("id", Integer.toString(id), Field.Store.NO));
+        for (Map.Entry<String, List<Object>> entry : keys.entrySet()) {
+            final String name = entry.getKey();
+            for (Object value : entry.getValue()) {
+                if (value instanceof Integer) {
+                    doc.add(new SortedNumericDocValuesField(name, (int) value));
+                    doc.add(new IntPoint(name, (int) value));
+                } else if (value instanceof Long) {
+                    doc.add(new SortedNumericDocValuesField(name, (long) value));
+                    doc.add(new LongPoint(name, (long) value));
+                } else if (value instanceof Double) {
+                    doc.add(new SortedNumericDocValuesField(name, NumericUtils.doubleToSortableLong((double) value)));
+                    doc.add(new DoublePoint(name, (double) value));
+                } else if (value instanceof String) {
+                    doc.add(new SortedSetDocValuesField(name, new BytesRef((String) value)));
+                    doc.add(new StringField(name, new BytesRef((String) value), Field.Store.NO));
+                } else if (value instanceof InetAddress) {
+                    doc.add(new SortedSetDocValuesField(name, new BytesRef(InetAddressPoint.encode((InetAddress) value))));
+                    doc.add(new InetAddressPoint(name, (InetAddress) value));
+                } else {
+                    if (!addValueToDocument(doc, name, value)) throw new AssertionError(
+                        "invalid object: " + value.getClass().getSimpleName()
+                    );
+                }
+            }
+        }
+    }
+
+    /**
+     * Override this function to handle any specific type of value you want to add in the document for doing the
+     * composite aggregation. If you have added another Composite Aggregation Type then you must override this
+     * function so that your field value can be added in the document correctly.
+     *
+     * @param doc {@link Document}
+     * @param name {@link String} Field Name
+     * @param value {@link Object} Field value
+     * @return boolean true or false, based on if value is added or not
+     */
+    protected boolean addValueToDocument(final Document doc, final String name, final Object value) {
+        return false;
+    }
+
+    protected static Sort buildIndexSort(List<CompositeValuesSourceBuilder<?>> sources, Map<String, MappedFieldType> fieldTypes) {
+        List<SortField> sortFields = new ArrayList<>();
+        Map<String, MappedFieldType> remainingFieldTypes = new HashMap<>(fieldTypes);
+        for (CompositeValuesSourceBuilder<?> source : sources) {
+            MappedFieldType type = fieldTypes.remove(source.field());
+            remainingFieldTypes.remove(source.field());
+            SortField sortField = sortFieldFrom(type);
+            if (sortField == null) {
+                break;
+            }
+            sortFields.add(sortField);
+        }
+        while (remainingFieldTypes.size() > 0 && randomBoolean()) {
+            // Add extra unused sorts
+            List<String> fields = new ArrayList<>(remainingFieldTypes.keySet());
+            Collections.sort(fields);
+            String field = fields.get(between(0, fields.size() - 1));
+            SortField sortField = sortFieldFrom(remainingFieldTypes.remove(field));
+            if (sortField != null) {
+                sortFields.add(sortField);
+            }
+        }
+        return sortFields.size() > 0 ? new Sort(sortFields.toArray(new SortField[0])) : null;
+    }
+
+    protected static SortField sortFieldFrom(MappedFieldType type) {
+        if (type instanceof KeywordFieldMapper.KeywordFieldType) {
+            return new SortedSetSortField(type.name(), false);
+        } else if (type instanceof DateFieldMapper.DateFieldType) {
+            return new SortedNumericSortField(type.name(), SortField.Type.LONG, false);
+        } else if (type instanceof NumberFieldMapper.NumberFieldType) {
+            switch (type.typeName()) {
+                case "byte":
+                case "short":
+                case "integer":
+                    return new SortedNumericSortField(type.name(), SortField.Type.INT, false);
+                case "long":
+                    return new SortedNumericSortField(type.name(), SortField.Type.LONG, false);
+                case "float":
+                case "double":
+                    return new SortedNumericSortField(type.name(), SortField.Type.DOUBLE, false);
+                default:
+                    return null;
+            }
+        }
+        return null;
+    }
+
+    protected static IndexSettings createIndexSettings(Sort sort) {
+        Settings.Builder builder = Settings.builder();
+        if (sort != null) {
+            String[] fields = Arrays.stream(sort.getSort()).map(SortField::getField).toArray(String[]::new);
+            String[] orders = Arrays.stream(sort.getSort()).map((o) -> o.getReverse() ? "desc" : "asc").toArray(String[]::new);
+            builder.putList("index.sort.field", fields);
+            builder.putList("index.sort.order", orders);
+        }
+        return IndexSettingsModule.newIndexSettings(new Index("_index", "0"), builder.build());
+    }
+
+    protected static Map<String, Object> createAfterKey(Object... fields) {
+        assert fields.length % 2 == 0;
+        final Map<String, Object> map = new HashMap<>();
+        for (int i = 0; i < fields.length; i += 2) {
+            String field = (String) fields[i];
+            map.put(field, fields[i + 1]);
+        }
+        return map;
+    }
+
+    protected static long asLong(String dateTime) {
+        return DateFormatters.from(DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER.parse(dateTime)).toInstant().toEpochMilli();
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/search/aggregations/metrics/AbstractNumericTestCase.java b/test/framework/src/main/java/org/opensearch/search/aggregations/metrics/AbstractNumericTestCase.java
index a4f6b97115bb0..103b67e2782de 100644
--- a/test/framework/src/main/java/org/opensearch/search/aggregations/metrics/AbstractNumericTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/search/aggregations/metrics/AbstractNumericTestCase.java
@@ -31,18 +31,43 @@
 
 package org.opensearch.search.aggregations.metrics;
 
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.ParameterizedOpenSearchIntegTestCase;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 
 @OpenSearchIntegTestCase.SuiteScopeTestCase
-public abstract class AbstractNumericTestCase extends OpenSearchIntegTestCase {
+public abstract class AbstractNumericTestCase extends ParameterizedOpenSearchIntegTestCase {
     protected static long minValue, maxValue, minValues, maxValues;
 
+    public AbstractNumericTestCase(Settings dynamicSettings) {
+        super(dynamicSettings);
+    }
+
+    @ParametersFactory
+    public static Collection<Object[]> parameters() {
+        return Arrays.asList(
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), false).build() },
+            new Object[] { Settings.builder().put(CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING.getKey(), true).build() }
+        );
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.CONCURRENT_SEGMENT_SEARCH, "true").build();
+    }
+
     @Override
     public void setupSuiteScopeCluster() throws Exception {
         createIndex("idx");
diff --git a/test/framework/src/main/java/org/opensearch/search/backpressure/SearchBackpressureTestHelpers.java b/test/framework/src/main/java/org/opensearch/search/backpressure/SearchBackpressureTestHelpers.java
new file mode 100644
index 0000000000000..af06b1688dca2
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/search/backpressure/SearchBackpressureTestHelpers.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.search.backpressure;
+
+import org.opensearch.core.tasks.resourcetracker.TaskResourceUsage;
+import org.opensearch.tasks.CancellableTask;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SearchBackpressureTestHelpers extends OpenSearchTestCase {
+
+    public static <T extends CancellableTask> T createMockTaskWithResourceStats(Class<T> type, long cpuUsage, long heapUsage) {
+        return createMockTaskWithResourceStats(type, cpuUsage, heapUsage, 0);
+    }
+
+    public static <T extends CancellableTask> T createMockTaskWithResourceStats(
+        Class<T> type,
+        long cpuUsage,
+        long heapUsage,
+        long startTimeNanos
+    ) {
+        T task = mock(type);
+        when(task.getTotalResourceStats()).thenReturn(new TaskResourceUsage(cpuUsage, heapUsage));
+        when(task.getStartTimeNanos()).thenReturn(startTimeNanos);
+
+        AtomicBoolean isCancelled = new AtomicBoolean(false);
+        doAnswer(invocation -> {
+            isCancelled.set(true);
+            return null;
+        }).when(task).cancel(anyString());
+        doAnswer(invocation -> isCancelled.get()).when(task).isCancelled();
+
+        return task;
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/snapshots/AbstractSnapshotIntegTestCase.java b/test/framework/src/main/java/org/opensearch/snapshots/AbstractSnapshotIntegTestCase.java
index 3a55848c46150..fa65a4e051e2b 100644
--- a/test/framework/src/main/java/org/opensearch/snapshots/AbstractSnapshotIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/snapshots/AbstractSnapshotIntegTestCase.java
@@ -32,7 +32,6 @@
 package org.opensearch.snapshots;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionFuture;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.action.index.IndexRequestBuilder;
@@ -49,17 +48,24 @@
 import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.action.ActionFuture;
+import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.compress.CompressorRegistry;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.IndexModule;
+import org.opensearch.index.store.RemoteBufferedOutputDirectory;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.node.NodeClosedException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
@@ -104,6 +110,7 @@
 
 public abstract class AbstractSnapshotIntegTestCase extends OpenSearchIntegTestCase {
 
+    protected final static String TEST_REMOTE_STORE_REPO_SUFFIX = "__rs";
     private static final String OLD_VERSION_SNAPSHOT_PREFIX = "old-version-snapshot-";
 
     // Large snapshot pool settings to set up nodes for tests involving multiple repositories that need to have enough
@@ -147,14 +154,19 @@ public void verifyNoLeakedListeners() throws Exception {
     @After
     public void assertRepoConsistency() {
         if (skipRepoConsistencyCheckReason == null) {
-            clusterAdmin().prepareGetRepositories().get().repositories().forEach(repositoryMetadata -> {
-                final String name = repositoryMetadata.name();
-                if (repositoryMetadata.settings().getAsBoolean("readonly", false) == false) {
-                    clusterAdmin().prepareDeleteSnapshot(name, OLD_VERSION_SNAPSHOT_PREFIX + "*").get();
-                    clusterAdmin().prepareCleanupRepository(name).get();
-                }
-                BlobStoreTestUtil.assertRepoConsistency(internalCluster(), name);
-            });
+            clusterAdmin().prepareGetRepositories()
+                .get()
+                .repositories()
+                .stream()
+                .filter(repositoryMetadata -> !repositoryMetadata.name().endsWith(TEST_REMOTE_STORE_REPO_SUFFIX))
+                .forEach(repositoryMetadata -> {
+                    final String name = repositoryMetadata.name();
+                    if (repositoryMetadata.settings().getAsBoolean("readonly", false) == false) {
+                        clusterAdmin().prepareDeleteSnapshot(name, OLD_VERSION_SNAPSHOT_PREFIX + "*").get();
+                        clusterAdmin().prepareCleanupRepository(name).get();
+                    }
+                    BlobStoreTestUtil.assertRepoConsistency(internalCluster(), name);
+                });
         } else {
             logger.info("--> skipped repo consistency checks because [{}]", skipRepoConsistencyCheckReason);
         }
@@ -166,7 +178,7 @@ protected void disableRepoConsistencyCheck(String reason) {
     }
 
     protected RepositoryData getRepositoryData(String repository) {
-        return getRepositoryData(internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repository));
+        return getRepositoryData(internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class).repository(repository));
     }
 
     protected RepositoryData getRepositoryData(Repository repository) {
@@ -175,7 +187,7 @@ protected RepositoryData getRepositoryData(Repository repository) {
 
     public static long getFailureCount(String repository) {
         long failureCount = 0;
-        for (RepositoriesService repositoriesService : internalCluster().getDataOrMasterNodeInstances(RepositoriesService.class)) {
+        for (RepositoriesService repositoriesService : internalCluster().getDataOrClusterManagerNodeInstances(RepositoriesService.class)) {
             MockRepository mockRepository = (MockRepository) repositoriesService.repository(repository);
             failureCount += mockRepository.getFailureCount();
         }
@@ -251,31 +263,55 @@ public SnapshotInfo waitForCompletion(String repository, String snapshotName, Ti
         return null;
     }
 
-    public static String blockMasterFromFinalizingSnapshotOnIndexFile(final String repositoryName) {
-        final String masterName = internalCluster().getMasterName();
-        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, masterName).repository(repositoryName))
+    public static String blockClusterManagerFromFinalizingSnapshotOnIndexFile(final String repositoryName) {
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerName).repository(repositoryName))
             .setBlockAndFailOnWriteIndexFile();
-        return masterName;
+        return clusterManagerName;
     }
 
-    public static String blockMasterOnWriteIndexFile(final String repositoryName) {
-        final String masterName = internalCluster().getMasterName();
-        ((MockRepository) internalCluster().getMasterNodeInstance(RepositoriesService.class).repository(repositoryName))
+    public static String blockClusterManagerOnWriteIndexFile(final String repositoryName) {
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        ((MockRepository) internalCluster().getClusterManagerNodeInstance(RepositoriesService.class).repository(repositoryName))
             .setBlockOnWriteIndexFile();
-        return masterName;
+        return clusterManagerName;
     }
 
-    public static void blockMasterFromDeletingIndexNFile(String repositoryName) {
-        final String masterName = internalCluster().getMasterName();
-        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, masterName).repository(repositoryName))
+    public static void blockClusterManagerFromDeletingIndexNFile(String repositoryName) {
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerName).repository(repositoryName))
             .setBlockOnDeleteIndexFile();
     }
 
-    public static String blockMasterFromFinalizingSnapshotOnSnapFile(final String repositoryName) {
-        final String masterName = internalCluster().getMasterName();
-        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, masterName).repository(repositoryName))
+    public static String blockClusterManagerFromFinalizingSnapshotOnSnapFile(final String repositoryName) {
+        final String clusterManagerName = internalCluster().getClusterManagerName();
+        ((MockRepository) internalCluster().getInstance(RepositoriesService.class, clusterManagerName).repository(repositoryName))
             .setBlockAndFailOnWriteSnapFiles(true);
-        return masterName;
+        return clusterManagerName;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #blockClusterManagerFromFinalizingSnapshotOnIndexFile(String)} */
+    @Deprecated
+    public static String blockMasterFromFinalizingSnapshotOnIndexFile(final String repositoryName) {
+        return blockClusterManagerFromFinalizingSnapshotOnIndexFile(repositoryName);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #blockClusterManagerOnWriteIndexFile(String)} */
+    @Deprecated
+    public static String blockMasterOnWriteIndexFile(final String repositoryName) {
+        return blockClusterManagerOnWriteIndexFile(repositoryName);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #blockClusterManagerFromDeletingIndexNFile(String)} */
+    @Deprecated
+    public static void blockMasterFromDeletingIndexNFile(String repositoryName) {
+        blockClusterManagerFromDeletingIndexNFile(repositoryName);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #blockClusterManagerFromFinalizingSnapshotOnSnapFile(String)} */
+    @Deprecated
+    public static String blockMasterFromFinalizingSnapshotOnSnapFile(final String repositoryName) {
+        return blockClusterManagerFromFinalizingSnapshotOnSnapFile(repositoryName);
     }
 
     public static String blockNodeWithIndex(final String repositoryName, final String indexName) {
@@ -342,23 +378,60 @@ protected void createRepository(String repoName, String type, Settings.Builder s
         assertAcked(clusterAdmin().preparePutRepository(repoName).setType(type).setSettings(settings));
     }
 
+    protected void updateRepository(String repoName, String type, Settings.Builder settings) {
+        logger.info("--> updating repository [{}] [{}]", repoName, type);
+        assertAcked(clusterAdmin().preparePutRepository(repoName).setType(type).setSettings(settings));
+    }
+
     protected void createRepository(String repoName, String type, Path location) {
         createRepository(repoName, type, Settings.builder().put("location", location));
     }
 
+    protected Settings.Builder getRepositorySettings(Path location, boolean shallowCopyEnabled) {
+        Settings.Builder settingsBuilder = randomRepositorySettings();
+        settingsBuilder.put("location", location);
+        if (shallowCopyEnabled) {
+            settingsBuilder.put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), true);
+        }
+        return settingsBuilder;
+    }
+
+    protected Settings.Builder getRepositorySettings(Path location, String basePath, boolean shallowCopyEnabled) {
+        Settings.Builder settingsBuilder = randomRepositorySettings();
+        settingsBuilder.put("location", location);
+        if (shallowCopyEnabled) {
+            settingsBuilder.put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), true);
+        }
+        if (basePath != null) {
+            settingsBuilder.put("base_path", basePath);
+        }
+        return settingsBuilder;
+    }
+
     protected void createRepository(String repoName, String type) {
         createRepository(repoName, type, randomRepositorySettings());
     }
 
     protected Settings.Builder randomRepositorySettings() {
         final Settings.Builder settings = Settings.builder();
-        settings.put("location", randomRepoPath()).put("compress", randomBoolean());
+        final boolean compress = randomBoolean();
+        settings.put("location", randomRepoPath()).put("compress", compress);
+        if (compress) {
+            settings.put("compression_type", randomFrom(CompressorRegistry.registeredCompressors().keySet()));
+        }
         if (rarely()) {
             settings.put("chunk_size", randomIntBetween(100, 1000), ByteSizeUnit.BYTES);
         }
         return settings;
     }
 
+    protected Settings.Builder snapshotRepoSettingsForShallowCopy() {
+        final Settings.Builder settings = Settings.builder();
+        settings.put("location", randomRepoPath());
+        settings.put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), Boolean.TRUE);
+        return settings;
+    }
+
     protected static Settings.Builder indexSettingsNoReplicas(int shards) {
         return Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, shards).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0);
     }
@@ -393,7 +466,7 @@ protected String initWithSnapshotVersion(String repoName, Path repoPath, Version
             JsonXContent.jsonXContent.createParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
-                Strings.toString(jsonBuilder).replace(Version.CURRENT.toString(), version.toString())
+                jsonBuilder.toString().replace(Version.CURRENT.toString(), version.toString())
             ),
             repositoryData.getGenId(),
             randomBoolean()
@@ -451,6 +524,24 @@ protected void indexRandomDocs(String index, int numdocs) throws InterruptedExce
         assertDocCount(index, numdocs);
     }
 
+    protected Settings getRemoteStoreBackedIndexSettings() {
+        return Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, "1")
+            .put("index.refresh_interval", "300s")
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, "1")
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey())
+            .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+    }
+
+    protected Settings.Builder snapshotRepoSettingsForShallowCopy(Path path) {
+        final Settings.Builder settings = Settings.builder();
+        settings.put("location", path);
+        settings.put(BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY.getKey(), Boolean.TRUE);
+        return settings;
+    }
+
     protected long getCountForIndex(String indexName) {
         return client().search(
             new SearchRequest(new SearchRequest(indexName).source(new SearchSourceBuilder().size(0).trackTotalHits(true)))
@@ -461,6 +552,26 @@ protected void assertDocCount(String index, long count) {
         assertEquals(getCountForIndex(index), count);
     }
 
+    protected String[] getLockFilesInRemoteStore(String remoteStoreIndex, String remoteStoreRepositoryName) throws IOException {
+        String indexUUID = client().admin()
+            .indices()
+            .prepareGetSettings(remoteStoreIndex)
+            .get()
+            .getSetting(remoteStoreIndex, IndexMetadata.SETTING_INDEX_UUID);
+        return getLockFilesInRemoteStore(remoteStoreIndex, remoteStoreRepositoryName, indexUUID);
+    }
+
+    protected String[] getLockFilesInRemoteStore(String remoteStoreIndex, String remoteStoreRepositoryName, String indexUUID)
+        throws IOException {
+        final RepositoriesService repositoriesService = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class);
+        final BlobStoreRepository remoteStoreRepository = (BlobStoreRepository) repositoriesService.repository(remoteStoreRepositoryName);
+        BlobPath shardLevelBlobPath = remoteStoreRepository.basePath().add(indexUUID).add("0").add("segments").add("lock_files");
+        BlobContainer blobContainer = remoteStoreRepository.blobStore().blobContainer(shardLevelBlobPath);
+        try (RemoteBufferedOutputDirectory lockDirectory = new RemoteBufferedOutputDirectory(blobContainer)) {
+            return lockDirectory.listAll();
+        }
+    }
+
     /**
      * Adds a snapshot in state {@link SnapshotState#FAILED} to the given repository.
      *
@@ -479,7 +590,7 @@ protected void addBwCFailedSnapshot(String repoName, String snapshotName, Map<St
             initialRepoMetadata.generation(),
             is(RepositoryData.UNKNOWN_REPO_GEN)
         );
-        final Repository repo = internalCluster().getCurrentMasterNodeInstance(RepositoriesService.class).repository(repoName);
+        final Repository repo = internalCluster().getCurrentClusterManagerNodeInstance(RepositoriesService.class).repository(repoName);
         final SnapshotId snapshotId = new SnapshotId(snapshotName, UUIDs.randomBase64UUID(random()));
         logger.info("--> adding old version FAILED snapshot [{}] to repository [{}]", snapshotId, repoName);
         final SnapshotInfo snapshotInfo = new SnapshotInfo(
@@ -495,7 +606,8 @@ protected void addBwCFailedSnapshot(String repoName, String snapshotName, Map<St
             0,
             Collections.emptyList(),
             randomBoolean(),
-            metadata
+            metadata,
+            false
         );
         PlainActionFuture.<RepositoryData, Exception>get(
             f -> repo.finalizeSnapshot(
@@ -511,7 +623,7 @@ protected void addBwCFailedSnapshot(String repoName, String snapshotName, Map<St
     }
 
     protected void awaitNoMoreRunningOperations() throws Exception {
-        awaitNoMoreRunningOperations(internalCluster().getMasterName());
+        awaitNoMoreRunningOperations(internalCluster().getClusterManagerName());
     }
 
     protected void awaitNoMoreRunningOperations(String viaNode) throws Exception {
@@ -524,7 +636,7 @@ protected void awaitNoMoreRunningOperations(String viaNode) throws Exception {
     }
 
     protected void awaitClusterState(Predicate<ClusterState> statePredicate) throws Exception {
-        awaitClusterState(internalCluster().getMasterName(), statePredicate);
+        awaitClusterState(internalCluster().getClusterManagerName(), statePredicate);
     }
 
     protected void awaitClusterState(String viaNode, Predicate<ClusterState> statePredicate) throws Exception {
@@ -601,7 +713,7 @@ protected ActionFuture<AcknowledgedResponse> startDeleteSnapshot(String repoName
 
     protected void updateClusterState(final Function<ClusterState, ClusterState> updater) throws Exception {
         final PlainActionFuture<Void> future = PlainActionFuture.newFuture();
-        final ClusterService clusterService = internalCluster().getCurrentMasterNodeInstance(ClusterService.class);
+        final ClusterService clusterService = internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class);
         clusterService.submitStateUpdateTask("test", new ClusterStateUpdateTask() {
             @Override
             public ClusterState execute(ClusterState currentState) {
@@ -627,11 +739,11 @@ protected SnapshotInfo getSnapshot(String repository, String snapshot) {
         return snapshotInfos.get(0);
     }
 
-    protected void awaitMasterFinishRepoOperations() throws Exception {
-        logger.info("--> waiting for master to finish all repo operations on its SNAPSHOT pool");
-        final ThreadPool masterThreadPool = internalCluster().getMasterNodeInstance(ThreadPool.class);
+    protected void awaitClusterManagerFinishRepoOperations() throws Exception {
+        logger.info("--> waiting for cluster-manager to finish all repo operations on its SNAPSHOT pool");
+        final ThreadPool clusterManagerThreadPool = internalCluster().getClusterManagerNodeInstance(ThreadPool.class);
         assertBusy(() -> {
-            for (ThreadPoolStats.Stats stat : masterThreadPool.stats()) {
+            for (ThreadPoolStats.Stats stat : clusterManagerThreadPool.stats()) {
                 if (ThreadPool.Names.SNAPSHOT.equals(stat.getName())) {
                     assertEquals(stat.getActive(), 0);
                     break;
@@ -639,4 +751,10 @@ protected void awaitMasterFinishRepoOperations() throws Exception {
             }
         });
     }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #awaitClusterManagerFinishRepoOperations()} */
+    @Deprecated
+    protected void awaitMasterFinishRepoOperations() throws Exception {
+        awaitClusterManagerFinishRepoOperations();
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/snapshots/mockstore/MockRepository.java b/test/framework/src/main/java/org/opensearch/snapshots/mockstore/MockRepository.java
index b26ffc9bd69d9..7db71c4be0968 100644
--- a/test/framework/src/main/java/org/opensearch/snapshots/mockstore/MockRepository.java
+++ b/test/framework/src/main/java/org/opensearch/snapshots/mockstore/MockRepository.java
@@ -33,6 +33,7 @@
 package org.opensearch.snapshots.mockstore;
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.CorruptIndexException;
@@ -50,7 +51,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.plugins.RepositoryPlugin;
@@ -78,6 +79,8 @@
 public class MockRepository extends FsRepository {
     private static final Logger logger = LogManager.getLogger(MockRepository.class);
 
+    private static final String DUMMY_FILE_NAME_LIST_BLOBS = "dummy-name-list-blobs";
+
     public static class Plugin extends org.opensearch.plugins.Plugin implements RepositoryPlugin {
 
         public static final Setting<String> USERNAME_SETTING = Setting.simpleString("secret.mock.username", Property.NodeScope);
@@ -112,10 +115,16 @@ public long getFailureCount() {
         return failureCounter.get();
     }
 
-    private final double randomControlIOExceptionRate;
+    private volatile double randomControlIOExceptionRate;
 
     private final double randomDataFileIOExceptionRate;
 
+    private final boolean skipExceptionOnVerificationFile;
+
+    private final boolean skipExceptionOnListBlobs;
+
+    private final List<String> skipExceptionOnBlobs;
+
     private final boolean useLuceneCorruptionException;
 
     private final long maximumNumberOfFailures;
@@ -143,7 +152,7 @@ public long getFailureCount() {
      */
     private volatile boolean blockOnWriteIndexFile;
 
-    /** Allows blocking on writing the snapshot file at the end of snapshot creation to simulate a died master node */
+    /** Allows blocking on writing the snapshot file at the end of snapshot creation to simulate a died cluster-manager node */
     private volatile boolean blockAndFailOnWriteSnapFile;
 
     private volatile boolean blockOnWriteShardLevelMeta;
@@ -174,6 +183,9 @@ public MockRepository(
         super(overrideSettings(metadata, environment), environment, namedXContentRegistry, clusterService, recoverySettings);
         randomControlIOExceptionRate = metadata.settings().getAsDouble("random_control_io_exception_rate", 0.0);
         randomDataFileIOExceptionRate = metadata.settings().getAsDouble("random_data_file_io_exception_rate", 0.0);
+        skipExceptionOnVerificationFile = metadata.settings().getAsBoolean("skip_exception_on_verification_file", false);
+        skipExceptionOnListBlobs = metadata.settings().getAsBoolean("skip_exception_on_list_blobs", false);
+        skipExceptionOnBlobs = metadata.settings().getAsList("skip_exception_on_blobs");
         useLuceneCorruptionException = metadata.settings().getAsBoolean("use_lucene_corruption", false);
         maximumNumberOfFailures = metadata.settings().getAsLong("max_failure_number", 100L);
         blockOnAnyFiles = metadata.settings().getAsBoolean("block_on_control", false);
@@ -191,7 +203,7 @@ public RepositoryMetadata getMetadata() {
     }
 
     private static RepositoryMetadata overrideSettings(RepositoryMetadata metadata, Environment environment) {
-        // TODO: use another method of testing not being able to read the test file written by the master...
+        // TODO: use another method of testing not being able to read the test file written by the cluster-manager...
         // this is super duper hacky
         if (metadata.settings().getAsBoolean("localize_location", false)) {
             Path location = PathUtils.get(metadata.settings().get("location"));
@@ -235,6 +247,10 @@ public synchronized void unblock() {
         this.notifyAll();
     }
 
+    public void setRandomControlIOExceptionRate(double randomControlIOExceptionRate) {
+        this.randomControlIOExceptionRate = randomControlIOExceptionRate;
+    }
+
     public void blockOnDataFiles(boolean blocked) {
         blockOnDataFiles = blocked;
     }
@@ -360,9 +376,16 @@ private int hashCode(String path) {
             }
 
             private void maybeIOExceptionOrBlock(String blobName) throws IOException {
-                if (INDEX_LATEST_BLOB.equals(blobName)) {
-                    // Don't mess with the index.latest blob here, failures to write to it are ignored by upstream logic and we have
-                    // specific tests that cover the error handling around this blob.
+                if (INDEX_LATEST_BLOB.equals(blobName) // Condition 1
+                    || skipExceptionOnVerificationFiles(blobName) // Condition 2
+                    || skipExceptionOnListBlobs(blobName) // Condition 3
+                    || skipExceptionOnBlob(blobName)) { // Condition 4
+                    // Condition 1 - Don't mess with the index.latest blob here, failures to write to it are ignored by
+                    // upstream logic and we have specific tests that cover the error handling around this blob.
+                    // Condition 2 & 3 - This condition has been added to allow creation of repository which throws IO
+                    // exception during normal remote store operations. However, if we fail during verification as well,
+                    // then we can not add the repository as well.
+                    // Condition 4 - This condition allows to skip exception on specific blobName or blobPrefix
                     return;
                 }
                 if (blobName.startsWith("__")) {
@@ -474,12 +497,15 @@ public void deleteBlobsIgnoringIfNotExists(List<String> blobNames) throws IOExce
                 if (blockOnDeleteIndexN && blobNames.stream().anyMatch(name -> name.startsWith(BlobStoreRepository.INDEX_FILE_PREFIX))) {
                     blockExecutionAndMaybeWait("index-{N}");
                 }
+                if (setThrowExceptionWhileDelete) {
+                    throw new IOException("Random exception");
+                }
                 super.deleteBlobsIgnoringIfNotExists(blobNames);
             }
 
             @Override
             public Map<String, BlobMetadata> listBlobs() throws IOException {
-                maybeIOExceptionOrBlock("");
+                maybeIOExceptionOrBlock(DUMMY_FILE_NAME_LIST_BLOBS);
                 return super.listBlobs();
             }
 
@@ -547,5 +573,28 @@ public void writeBlobAtomic(
                 }
             }
         }
+
+        private boolean skipExceptionOnVerificationFiles(String blobName) {
+            return skipExceptionOnVerificationFile && isVerificationFile(blobName);
+        }
+
+        /**
+         * Checks if the file name is one of the types of verification files that is created at the time of creation of
+         * repository.
+         *
+         * @param blobName name of the blob
+         * @return true if it is the file created at the time of repository creation
+         */
+        private boolean isVerificationFile(String blobName) {
+            return blobName.equals("master.dat") || (blobName.startsWith("data-") && blobName.endsWith(".dat"));
+        }
+
+        private boolean skipExceptionOnListBlobs(String blobName) {
+            return skipExceptionOnListBlobs && DUMMY_FILE_NAME_LIST_BLOBS.equals(blobName);
+        }
+
+        private boolean skipExceptionOnBlob(String blobName) {
+            return skipExceptionOnBlobs.contains(blobName);
+        }
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractBroadcastResponseTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractBroadcastResponseTestCase.java
index d43ae76da97df..61621c851bcb0 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractBroadcastResponseTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractBroadcastResponseTestCase.java
@@ -33,16 +33,17 @@
 package org.opensearch.test;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.index.Index;
-import org.opensearch.index.shard.ShardId;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -150,7 +151,7 @@ public void testFailuresDeduplication() throws IOException {
 
     public void testToXContent() {
         T response = createTestInstance(10, 10, 0, null);
-        String output = Strings.toString(response);
+        String output = Strings.toString(MediaTypeRegistry.JSON, response);
         assertEquals("{\"_shards\":{\"total\":10,\"successful\":10,\"failed\":0}}", output);
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractBuilderTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractBuilderTestCase.java
index ae32db5fe6032..656397d7673d6 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractBuilderTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractBuilderTestCase.java
@@ -35,10 +35,10 @@
 import com.carrotsearch.randomizedtesting.RandomizedTest;
 import com.carrotsearch.randomizedtesting.SeedUtils;
 
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.util.Accountable;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.action.get.GetResponse;
@@ -47,20 +47,22 @@
 import org.opensearch.action.termvectors.MultiTermVectorsResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.Strings;
 import org.opensearch.common.compress.CompressedXContent;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.SettingsModule;
 import org.opensearch.common.util.BigArrays;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
@@ -68,12 +70,12 @@
 import org.opensearch.index.fielddata.IndexFieldDataService;
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.QueryBuilderVisitor;
 import org.opensearch.index.query.QueryShardContext;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.analysis.AnalysisModule;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.node.InternalSettingsPreparer;
@@ -248,10 +250,10 @@ public void beforeTest() throws Exception {
             assert serviceHolderWithNoType == null;
             // we initialize the serviceHolder and serviceHolderWithNoType just once, but need some
             // calls to the randomness source during its setup. In order to not mix these calls with
-            // the randomness source that is later used in the test method, we use the master seed during
+            // the randomness source that is later used in the test method, we use the cluster-manager seed during
             // this setup
-            long masterSeed = SeedUtils.parseSeed(RandomizedTest.getContext().getRunnerSeedAsString());
-            RandomizedTest.getContext().runWithPrivateRandomness(masterSeed, (Callable<Void>) () -> {
+            long clusterManagerSeed = SeedUtils.parseSeed(RandomizedTest.getContext().getRunnerSeedAsString());
+            RandomizedTest.getContext().runWithPrivateRandomness(clusterManagerSeed, (Callable<Void>) () -> {
                 serviceHolder = new ServiceHolder(
                     nodeSettings,
                     createTestIndexSettings(),
@@ -317,6 +319,20 @@ protected static QueryShardContext createShardContext() {
         return createShardContext(null);
     }
 
+    protected static QueryBuilderVisitor createTestVisitor(List<QueryBuilder> visitedQueries) {
+        return new QueryBuilderVisitor() {
+            @Override
+            public void accept(QueryBuilder qb) {
+                visitedQueries.add(qb);
+            }
+
+            @Override
+            public QueryBuilderVisitor getChildVisitor(BooleanClause.Occur occur) {
+                return this;
+            }
+        };
+    }
+
     private static class ClientInvocationHandler implements InvocationHandler {
         AbstractBuilderTestCase delegate;
 
@@ -369,12 +385,9 @@ private static class ServiceHolder implements Closeable {
             boolean registerType
         ) throws IOException {
             this.nowInMillis = nowInMillis;
-            Environment env = InternalSettingsPreparer.prepareEnvironment(
-                nodeSettings,
-                emptyMap(),
-                null,
-                () -> { throw new AssertionError("node.name must be set"); }
-            );
+            Environment env = InternalSettingsPreparer.prepareEnvironment(nodeSettings, emptyMap(), null, () -> {
+                throw new AssertionError("node.name must be set");
+            });
             PluginsService pluginsService;
             pluginsService = new PluginsService(nodeSettings, null, env.modulesFile(), env.pluginsFile(), plugins);
 
@@ -437,42 +450,40 @@ public void onRemoval(ShardId shardId, Accountable accountable) {
                 mapperService.merge(
                     "_doc",
                     new CompressedXContent(
-                        Strings.toString(
-                            PutMappingRequest.simpleMapping(
-                                TEXT_FIELD_NAME,
-                                "type=text",
-                                KEYWORD_FIELD_NAME,
-                                "type=keyword",
-                                TEXT_ALIAS_FIELD_NAME,
-                                "type=alias,path=" + TEXT_FIELD_NAME,
-                                INT_FIELD_NAME,
-                                "type=integer",
-                                INT_ALIAS_FIELD_NAME,
-                                "type=alias,path=" + INT_FIELD_NAME,
-                                INT_RANGE_FIELD_NAME,
-                                "type=integer_range",
-                                DOUBLE_FIELD_NAME,
-                                "type=double",
-                                BOOLEAN_FIELD_NAME,
-                                "type=boolean",
-                                DATE_NANOS_FIELD_NAME,
-                                "type=date_nanos",
-                                DATE_FIELD_NAME,
-                                "type=date",
-                                DATE_ALIAS_FIELD_NAME,
-                                "type=alias,path=" + DATE_FIELD_NAME,
-                                DATE_RANGE_FIELD_NAME,
-                                "type=date_range",
-                                OBJECT_FIELD_NAME,
-                                "type=object",
-                                GEO_POINT_FIELD_NAME,
-                                "type=geo_point",
-                                GEO_POINT_ALIAS_FIELD_NAME,
-                                "type=alias,path=" + GEO_POINT_FIELD_NAME,
-                                GEO_SHAPE_FIELD_NAME,
-                                "type=geo_shape"
-                            )
-                        )
+                        PutMappingRequest.simpleMapping(
+                            TEXT_FIELD_NAME,
+                            "type=text",
+                            KEYWORD_FIELD_NAME,
+                            "type=keyword",
+                            TEXT_ALIAS_FIELD_NAME,
+                            "type=alias,path=" + TEXT_FIELD_NAME,
+                            INT_FIELD_NAME,
+                            "type=integer",
+                            INT_ALIAS_FIELD_NAME,
+                            "type=alias,path=" + INT_FIELD_NAME,
+                            INT_RANGE_FIELD_NAME,
+                            "type=integer_range",
+                            DOUBLE_FIELD_NAME,
+                            "type=double",
+                            BOOLEAN_FIELD_NAME,
+                            "type=boolean",
+                            DATE_NANOS_FIELD_NAME,
+                            "type=date_nanos",
+                            DATE_FIELD_NAME,
+                            "type=date",
+                            DATE_ALIAS_FIELD_NAME,
+                            "type=alias,path=" + DATE_FIELD_NAME,
+                            DATE_RANGE_FIELD_NAME,
+                            "type=date_range",
+                            OBJECT_FIELD_NAME,
+                            "type=object",
+                            GEO_POINT_FIELD_NAME,
+                            "type=geo_point",
+                            GEO_POINT_ALIAS_FIELD_NAME,
+                            "type=alias,path=" + GEO_POINT_FIELD_NAME,
+                            GEO_SHAPE_FIELD_NAME,
+                            "type=geo_shape"
+                        ).toString()
                     ),
                     MapperService.MergeReason.MAPPING_UPDATE
                 );
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractDiffableSerializationTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractDiffableSerializationTestCase.java
index 19c12903b726a..f5d358a162bd1 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractDiffableSerializationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractDiffableSerializationTestCase.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.Diffable;
-import org.opensearch.common.io.stream.Writeable.Reader;
-import org.opensearch.common.xcontent.ToXContent;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.ToXContent;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractDiffableWireSerializationTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractDiffableWireSerializationTestCase.java
index 4c692cc2bf726..ff7c39cd8f102 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractDiffableWireSerializationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractDiffableWireSerializationTestCase.java
@@ -34,7 +34,7 @@
 
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.Diffable;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractMultiClustersTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractMultiClustersTestCase.java
index 69d30beaa8e16..f50603a7d8e1e 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractMultiClustersTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractMultiClustersTestCase.java
@@ -37,7 +37,7 @@
 import org.opensearch.client.Client;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.RemoteClusterAware;
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractNamedWriteableTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractNamedWriteableTestCase.java
index b78160704992c..d1bdc621a92dd 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractNamedWriteableTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractNamedWriteableTestCase.java
@@ -33,9 +33,9 @@
 package org.opensearch.test;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractQueryTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractQueryTestCase.java
index 7ce7903296a5a..47fe85d28975f 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractQueryTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractQueryTestCase.java
@@ -41,26 +41,27 @@
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.action.support.PlainActionFuture;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable.Reader;
 import org.opensearch.common.unit.Fuzziness;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentGenerator;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentGenerator;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.query.AbstractQueryBuilder;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryRewriteContext;
@@ -262,7 +263,7 @@ static List<Tuple<String, Boolean>> alterateQueries(Set<String> queries, Set<Str
 
                 BytesStreamOutput out = new BytesStreamOutput();
                 try (
-                    XContentGenerator generator = XContentType.JSON.xContent().createGenerator(out);
+                    XContentGenerator generator = MediaTypeRegistry.JSON.xContent().createGenerator(out);
                     XContentParser parser = JsonXContent.jsonXContent.createParser(
                         NamedXContentRegistry.EMPTY,
                         DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -408,7 +409,7 @@ private void assertParsedQuery(XContentParser parser, QueryBuilder expectedQuery
     }
 
     protected QueryBuilder parseQuery(AbstractQueryBuilder<?> builder) throws IOException {
-        BytesReference bytes = XContentHelper.toXContent(builder, XContentType.JSON, false);
+        BytesReference bytes = org.opensearch.core.xcontent.XContentHelper.toXContent(builder, MediaTypeRegistry.JSON, false);
         return parseQuery(createParser(JsonXContent.jsonXContent, bytes));
     }
 
@@ -633,11 +634,11 @@ public QB mutateInstance(QB instance) throws IOException {
     public void testValidOutput() throws IOException {
         for (int runs = 0; runs < NUMBER_OF_TESTQUERIES; runs++) {
             QB testQuery = createTestQueryBuilder();
-            XContentType xContentType = XContentType.JSON;
-            String toString = Strings.toString(testQuery);
-            assertParsedQuery(createParser(xContentType.xContent(), toString), testQuery);
-            BytesReference bytes = XContentHelper.toXContent(testQuery, xContentType, false);
-            assertParsedQuery(createParser(xContentType.xContent(), bytes), testQuery);
+            MediaType mediaType = MediaTypeRegistry.JSON;
+            String toString = Strings.toString(MediaTypeRegistry.JSON, testQuery);
+            assertParsedQuery(createParser(mediaType.xContent(), toString), testQuery);
+            BytesReference bytes = org.opensearch.core.xcontent.XContentHelper.toXContent(testQuery, mediaType, false);
+            assertParsedQuery(createParser(mediaType.xContent(), bytes), testQuery);
         }
     }
 
@@ -732,7 +733,8 @@ protected static String getRandomRewriteMethod() {
                 .getPreferredName();
         } else {
             rewrite = randomFrom(QueryParsers.TOP_TERMS, QueryParsers.TOP_TERMS_BOOST, QueryParsers.TOP_TERMS_BLENDED_FREQS)
-                .getPreferredName() + "1";
+                .getPreferredName()
+                + "1";
         }
         return rewrite;
     }
@@ -783,11 +785,7 @@ public static void checkGeneratedJson(String expected, QueryBuilder source) thro
         // now assert that we actually generate the same JSON
         XContentBuilder builder = XContentFactory.jsonBuilder().prettyPrint();
         source.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        assertEquals(
-            msg(expected, Strings.toString(builder)),
-            expected.replaceAll("\\s+", ""),
-            Strings.toString(builder).replaceAll("\\s+", "")
-        );
+        assertEquals(msg(expected, builder.toString()), expected.replaceAll("\\s+", ""), builder.toString().replaceAll("\\s+", ""));
     }
 
     private static String msg(String left, String right) {
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractSerializingTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractSerializingTestCase.java
index 8f649e06082e7..e85a8631d8b62 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractSerializingTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractSerializingTestCase.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.test;
 
-import org.opensearch.common.Strings;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -74,7 +76,7 @@ public final void testFromXContent() throws IOException {
      * Override this method if the random instance that you build
      * should be aware of the {@link XContentType} used in the test.
      */
-    protected T createXContextTestInstance(XContentType xContentType) {
+    protected T createXContextTestInstance(final MediaType mediaType) {
         return createTestInstance();
     }
 
@@ -108,8 +110,8 @@ protected ToXContent.Params getToXContentParams() {
     }
 
     /**
-     * Whether or not to assert equivalence of the {@link org.opensearch.common.xcontent.XContent} of the test instance and the instance
-     * parsed from the {@link org.opensearch.common.xcontent.XContent} of the test instance.
+     * Whether or not to assert equivalence of the {@link XContent} of the test instance and the instance
+     * parsed from the {@link XContent} of the test instance.
      *
      * @return true if equivalence should be asserted, otherwise false
      */
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractWireSerializingTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractWireSerializingTestCase.java
index 0ae8f5f2c2012..4091f9dc61884 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractWireSerializingTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractWireSerializingTestCase.java
@@ -32,10 +32,10 @@
 package org.opensearch.test;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractWireTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractWireTestCase.java
index ac5b48675481e..9a4363dc4d946 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractWireTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractWireTestCase.java
@@ -33,9 +33,9 @@
 package org.opensearch.test;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/test/framework/src/main/java/org/opensearch/test/AbstractXContentTestCase.java b/test/framework/src/main/java/org/opensearch/test/AbstractXContentTestCase.java
index 7c01b3ad13758..bcb900aee51fb 100644
--- a/test/framework/src/main/java/org/opensearch/test/AbstractXContentTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/AbstractXContentTestCase.java
@@ -35,15 +35,15 @@
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedBiFunction;
 import org.opensearch.common.CheckedFunction;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.function.BiConsumer;
@@ -94,7 +94,7 @@ public static <T extends ToXContent> XContentTester<T> xContentTester(
 
     public static <T extends ToXContent> XContentTester<T> xContentTester(
         CheckedBiFunction<XContent, BytesReference, XContentParser, IOException> createParser,
-        Function<XContentType, T> instanceSupplier,
+        Function<MediaType, T> instanceSupplier,
         ToXContent.Params toXContentParams,
         CheckedFunction<XContentParser, T, IOException> fromXContent
     ) {
@@ -111,8 +111,8 @@ public static <T extends ToXContent> XContentTester<T> xContentTester(
      */
     public static class XContentTester<T> {
         private final CheckedBiFunction<XContent, BytesReference, XContentParser, IOException> createParser;
-        private final Function<XContentType, T> instanceSupplier;
-        private final CheckedBiFunction<T, XContentType, BytesReference, IOException> toXContent;
+        private final Function<MediaType, T> instanceSupplier;
+        private final CheckedBiFunction<T, MediaType, BytesReference, IOException> toXContent;
         private final CheckedFunction<XContentParser, T, IOException> fromXContent;
 
         private int numberOfTestRuns = NUMBER_OF_TEST_RUNS;
@@ -128,8 +128,8 @@ public static class XContentTester<T> {
 
         private XContentTester(
             CheckedBiFunction<XContent, BytesReference, XContentParser, IOException> createParser,
-            Function<XContentType, T> instanceSupplier,
-            CheckedBiFunction<T, XContentType, BytesReference, IOException> toXContent,
+            Function<MediaType, T> instanceSupplier,
+            CheckedBiFunction<T, MediaType, BytesReference, IOException> toXContent,
             CheckedFunction<XContentParser, T, IOException> fromXContent
         ) {
             this.createParser = createParser;
@@ -151,7 +151,7 @@ public void test() throws IOException {
                     randomFieldsExcludeFilter,
                     createParser
                 );
-                XContentParser parser = createParser.apply(XContentFactory.xContent(xContentType), shuffledContent);
+                XContentParser parser = createParser.apply(xContentType.xContent(), shuffledContent);
                 T parsed = fromXContent.apply(parser);
                 assertEqualsConsumer.accept(testInstance, parsed);
                 if (assertToXContentEquivalence) {
@@ -292,7 +292,7 @@ protected ToXContent.Params getToXContentParams() {
 
     static BytesReference insertRandomFieldsAndShuffle(
         BytesReference xContent,
-        XContentType xContentType,
+        MediaType mediaType,
         boolean supportsUnknownFields,
         String[] shuffleFieldsExceptions,
         Predicate<String> randomFieldsExcludeFilter,
@@ -301,11 +301,11 @@ static BytesReference insertRandomFieldsAndShuffle(
         BytesReference withRandomFields;
         if (supportsUnknownFields) {
             // add a few random fields to check that the parser is lenient on new fields
-            withRandomFields = XContentTestUtils.insertRandomFields(xContentType, xContent, randomFieldsExcludeFilter, random());
+            withRandomFields = XContentTestUtils.insertRandomFields(mediaType, xContent, randomFieldsExcludeFilter, random());
         } else {
             withRandomFields = xContent;
         }
-        XContentParser parserWithRandonFields = createParserFunction.apply(XContentFactory.xContent(xContentType), withRandomFields);
+        XContentParser parserWithRandonFields = createParserFunction.apply(mediaType.xContent(), withRandomFields);
         return BytesReference.bytes(shuffleXContent(parserWithRandonFields, false, shuffleFieldsExceptions));
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/test/BackgroundIndexer.java b/test/framework/src/main/java/org/opensearch/test/BackgroundIndexer.java
index f7271a5fe8c20..22ba6ed2c4224 100644
--- a/test/framework/src/main/java/org/opensearch/test/BackgroundIndexer.java
+++ b/test/framework/src/main/java/org/opensearch/test/BackgroundIndexer.java
@@ -35,6 +35,7 @@
 import com.carrotsearch.randomizedtesting.RandomizedTest;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -47,8 +48,8 @@
 import org.opensearch.client.Client;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.junit.Assert;
 
 import java.io.IOException;
@@ -79,7 +80,9 @@ public class BackgroundIndexer implements AutoCloseable {
     final CountDownLatch startLatch = new CountDownLatch(1);
     final AtomicBoolean hasBudget = new AtomicBoolean(false); // when set to true, writers will acquire writes from a semaphore
     final Semaphore availableBudget = new Semaphore(0);
-    final boolean useAutoGeneratedIDs;
+    boolean useAutoGeneratedIDs;
+
+    private boolean autoStart = false;
     private final Set<String> ids = ConcurrentCollections.newConcurrentSet();
     private volatile Consumer<Exception> failureAssertion = null;
 
@@ -246,6 +249,7 @@ public void run() {
         }
 
         if (autoStart) {
+            this.autoStart = true;
             start(numOfDocs);
         }
     }
@@ -260,6 +264,16 @@ private void trackFailure(Exception e) {
         }
     }
 
+    public void setUseAutoGeneratedIDs(boolean useAutoGeneratedIDs) {
+        // this should only be set when auto run is set to false to ensure no indexing has started
+        if (this.autoStart == false) {
+            this.useAutoGeneratedIDs = useAutoGeneratedIDs;
+        } else {
+            logger.error("Auto generated ids can be set only when autoStart is set to false");
+        }
+
+    }
+
     private XContentBuilder generateSource(long id, Random random) throws IOException {
         int contentLength = RandomNumbers.randomIntBetween(random, minFieldSize, maxFieldSize);
         StringBuilder text = new StringBuilder(contentLength);
diff --git a/test/framework/src/main/java/org/opensearch/test/ClusterServiceUtils.java b/test/framework/src/main/java/org/opensearch/test/ClusterServiceUtils.java
index b97a35a3431b6..8f4f510da5ec3 100644
--- a/test/framework/src/main/java/org/opensearch/test/ClusterServiceUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/ClusterServiceUtils.java
@@ -46,6 +46,7 @@
 import org.opensearch.cluster.service.ClusterApplier;
 import org.opensearch.cluster.service.ClusterApplier.ClusterApplyListener;
 import org.opensearch.cluster.service.ClusterApplierService;
+import org.opensearch.cluster.service.ClusterManagerService;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.cluster.service.MasterService;
 import org.opensearch.common.settings.ClusterSettings;
@@ -61,28 +62,40 @@
 
 public class ClusterServiceUtils {
 
-    public static MasterService createMasterService(ThreadPool threadPool, ClusterState initialClusterState) {
-        MasterService masterService = new MasterService(
-            Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), "test_master_node").build(),
+    public static ClusterManagerService createClusterManagerService(ThreadPool threadPool, ClusterState initialClusterState) {
+        ClusterManagerService clusterManagerService = new ClusterManagerService(
+            Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), "test_cluster_manager_node").build(),
             new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS),
             threadPool
         );
         AtomicReference<ClusterState> clusterStateRef = new AtomicReference<>(initialClusterState);
-        masterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+        clusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
             clusterStateRef.set(event.state());
             publishListener.onResponse(null);
         });
-        masterService.setClusterStateSupplier(clusterStateRef::get);
-        masterService.start();
-        return masterService;
+        clusterManagerService.setClusterStateSupplier(clusterStateRef::get);
+        clusterManagerService.start();
+        return clusterManagerService;
     }
 
-    public static MasterService createMasterService(ThreadPool threadPool, DiscoveryNode localNode) {
+    public static ClusterManagerService createClusterManagerService(ThreadPool threadPool, DiscoveryNode localNode) {
         ClusterState initialClusterState = ClusterState.builder(new ClusterName(ClusterServiceUtils.class.getSimpleName()))
-            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).masterNodeId(localNode.getId()))
+            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).clusterManagerNodeId(localNode.getId()))
             .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
             .build();
-        return createMasterService(threadPool, initialClusterState);
+        return createClusterManagerService(threadPool, initialClusterState);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #createClusterManagerService(ThreadPool, ClusterState)} */
+    @Deprecated
+    public static MasterService createMasterService(ThreadPool threadPool, ClusterState initialClusterState) {
+        return createClusterManagerService(threadPool, initialClusterState);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #createClusterManagerService(ThreadPool, DiscoveryNode)} */
+    @Deprecated
+    public static MasterService createMasterService(ThreadPool threadPool, DiscoveryNode localNode) {
+        return createClusterManagerService(threadPool, localNode);
     }
 
     public static void setState(ClusterApplierService executor, ClusterState clusterState) {
@@ -114,7 +127,7 @@ public void onFailure(String source, Exception e) {
         }
     }
 
-    public static void setState(MasterService executor, ClusterState clusterState) {
+    public static void setState(ClusterManagerService executor, ClusterState clusterState) {
         CountDownLatch latch = new CountDownLatch(1);
         executor.submitStateUpdateTask("test setting state", new ClusterStateUpdateTask() {
             @Override
@@ -160,12 +173,13 @@ public static ClusterService createClusterService(ThreadPool threadPool, Discove
         ClusterService clusterService = new ClusterService(settings, clusterSettings, threadPool);
         clusterService.setNodeConnectionsService(createNoOpNodeConnectionsService());
         ClusterState initialClusterState = ClusterState.builder(new ClusterName(ClusterServiceUtils.class.getSimpleName()))
-            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).masterNodeId(localNode.getId()))
+            .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).clusterManagerNodeId(localNode.getId()))
             .blocks(ClusterBlocks.EMPTY_CLUSTER_BLOCK)
             .build();
         clusterService.getClusterApplierService().setInitialState(initialClusterState);
-        clusterService.getMasterService().setClusterStatePublisher(createClusterStatePublisher(clusterService.getClusterApplierService()));
-        clusterService.getMasterService().setClusterStateSupplier(clusterService.getClusterApplierService()::state);
+        clusterService.getClusterManagerService()
+            .setClusterStatePublisher(createClusterStatePublisher(clusterService.getClusterApplierService()));
+        clusterService.getClusterManagerService().setClusterStateSupplier(clusterService.getClusterApplierService()::state);
         clusterService.start();
         return clusterService;
     }
diff --git a/test/framework/src/main/java/org/opensearch/test/CorruptionUtils.java b/test/framework/src/main/java/org/opensearch/test/CorruptionUtils.java
index abfb3edc26417..0dce5e78bf91f 100644
--- a/test/framework/src/main/java/org/opensearch/test/CorruptionUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/CorruptionUtils.java
@@ -32,8 +32,9 @@
 package org.opensearch.test;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
-import org.apache.logging.log4j.Logger;
+
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.store.ChecksumIndexInput;
@@ -50,9 +51,9 @@
 import java.nio.file.StandardOpenOption;
 import java.util.Random;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.assumeTrue;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.apache.lucene.tests.util.LuceneTestCase.assumeTrue;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/DiffableTestUtils.java b/test/framework/src/main/java/org/opensearch/test/DiffableTestUtils.java
index 50b9e02f84c21..25d3b1d9e6c5a 100644
--- a/test/framework/src/main/java/org/opensearch/test/DiffableTestUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/DiffableTestUtils.java
@@ -35,11 +35,11 @@
 import org.opensearch.cluster.Diff;
 import org.opensearch.cluster.Diffable;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
-import org.opensearch.common.io.stream.Writeable.Reader;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.io.stream.Writeable.Reader;
 
 import java.io.IOException;
 import java.util.function.Function;
diff --git a/test/framework/src/main/java/org/opensearch/test/DummyShardLock.java b/test/framework/src/main/java/org/opensearch/test/DummyShardLock.java
index fbd2a03d6a9c2..36d6c1987dc2b 100644
--- a/test/framework/src/main/java/org/opensearch/test/DummyShardLock.java
+++ b/test/framework/src/main/java/org/opensearch/test/DummyShardLock.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test;
 
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.env.ShardLock;
-import org.opensearch.index.shard.ShardId;
 
 /*
  * A ShardLock that does nothing... for tests only
diff --git a/test/framework/src/main/java/org/opensearch/test/ExternalTestCluster.java b/test/framework/src/main/java/org/opensearch/test/ExternalTestCluster.java
index 805e578a8e8db..3eb1680069b06 100644
--- a/test/framework/src/main/java/org/opensearch/test/ExternalTestCluster.java
+++ b/test/framework/src/main/java/org/opensearch/test/ExternalTestCluster.java
@@ -41,11 +41,11 @@
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.env.Environment;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.node.MockNode;
@@ -90,7 +90,7 @@ public final class ExternalTestCluster extends TestCluster {
     private final String clusterName;
 
     private final int numDataNodes;
-    private final int numMasterAndDataNodes;
+    private final int numClusterManagerAndDataNodes;
 
     public ExternalTestCluster(
         Path tempDir,
@@ -141,19 +141,19 @@ public ExternalTestCluster(
                 .get();
             httpAddresses = new InetSocketAddress[nodeInfos.getNodes().size()];
             int dataNodes = 0;
-            int masterAndDataNodes = 0;
+            int clusterManagerAndDataNodes = 0;
             for (int i = 0; i < nodeInfos.getNodes().size(); i++) {
                 NodeInfo nodeInfo = nodeInfos.getNodes().get(i);
                 httpAddresses[i] = nodeInfo.getInfo(HttpInfo.class).address().publishAddress().address();
                 if (DiscoveryNode.isDataNode(nodeInfo.getSettings())) {
                     dataNodes++;
-                    masterAndDataNodes++;
-                } else if (DiscoveryNode.isMasterNode(nodeInfo.getSettings())) {
-                    masterAndDataNodes++;
+                    clusterManagerAndDataNodes++;
+                } else if (DiscoveryNode.isClusterManagerNode(nodeInfo.getSettings())) {
+                    clusterManagerAndDataNodes++;
                 }
             }
             this.numDataNodes = dataNodes;
-            this.numMasterAndDataNodes = masterAndDataNodes;
+            this.numClusterManagerAndDataNodes = clusterManagerAndDataNodes;
             this.client = client;
             this.node = node;
 
@@ -190,8 +190,8 @@ public int numDataNodes() {
     }
 
     @Override
-    public int numDataAndMasterNodes() {
-        return numMasterAndDataNodes;
+    public int numDataAndClusterManagerNodes() {
+        return numClusterManagerAndDataNodes;
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/opensearch/test/FeatureFlagSetter.java b/test/framework/src/main/java/org/opensearch/test/FeatureFlagSetter.java
new file mode 100644
index 0000000000000..eddcf9c738bb3
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/FeatureFlagSetter.java
@@ -0,0 +1,64 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.util.concurrent.ConcurrentCollections;
+
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Set;
+
+/**
+ * Helper class that wraps the lifecycle of setting and finally clearing of
+ * a {@link org.opensearch.common.util.FeatureFlags} string.
+ */
+public class FeatureFlagSetter {
+
+    private static FeatureFlagSetter INSTANCE = null;
+
+    private static synchronized FeatureFlagSetter getInstance() {
+        if (INSTANCE == null) {
+            INSTANCE = new FeatureFlagSetter();
+        }
+        return INSTANCE;
+    }
+
+    public static synchronized void set(String flag) {
+        getInstance().setFlag(flag);
+    }
+
+    public static synchronized void clear() {
+        if (INSTANCE != null) {
+            INSTANCE.clearAll();
+            INSTANCE = null;
+        }
+    }
+
+    private static final Logger LOGGER = LogManager.getLogger(FeatureFlagSetter.class);
+    private final Set<String> flags = ConcurrentCollections.newConcurrentSet();
+
+    @SuppressForbidden(reason = "Enables setting of feature flags")
+    private void setFlag(String flag) {
+        flags.add(flag);
+        AccessController.doPrivileged((PrivilegedAction<String>) () -> System.setProperty(flag, "true"));
+        LOGGER.info("set feature_flag={}", flag);
+    }
+
+    @SuppressForbidden(reason = "Clears the set feature flags")
+    private void clearAll() {
+        for (String flag : flags) {
+            AccessController.doPrivileged((PrivilegedAction<String>) () -> System.clearProperty(flag));
+        }
+        LOGGER.info("unset feature_flags={}", flags);
+        flags.clear();
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/FieldMaskingReader.java b/test/framework/src/main/java/org/opensearch/test/FieldMaskingReader.java
index dba42b546c1a2..8dbf7514bc8e4 100644
--- a/test/framework/src/main/java/org/opensearch/test/FieldMaskingReader.java
+++ b/test/framework/src/main/java/org/opensearch/test/FieldMaskingReader.java
@@ -32,10 +32,10 @@
 package org.opensearch.test;
 
 import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.tests.index.FieldFilterLeafReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.FilterLeafReader;
 import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.tests.index.FieldFilterLeafReader;
 
 import java.io.IOException;
 import java.util.Collections;
diff --git a/test/framework/src/main/java/org/opensearch/test/IndexSettingsModule.java b/test/framework/src/main/java/org/opensearch/test/IndexSettingsModule.java
index b98b69a1c4201..2aea390fdc7f5 100644
--- a/test/framework/src/main/java/org/opensearch/test/IndexSettingsModule.java
+++ b/test/framework/src/main/java/org/opensearch/test/IndexSettingsModule.java
@@ -37,7 +37,7 @@
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
 import org.opensearch.index.IndexSettings;
 
 import java.util.Arrays;
diff --git a/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java b/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
index 6be7abffb9ad6..35cc8498b2320 100644
--- a/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
@@ -32,22 +32,22 @@
 
 package org.opensearch.test;
 
-import org.apache.lucene.util.SetOnce;
-import org.opensearch.common.ParseField;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.BigArrays;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.common.xcontent.ContextParser;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParserUtils;
 import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.xcontent.ContextParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParserUtils;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.plugins.SearchPlugin;
 import org.opensearch.rest.action.search.RestSearchAction;
@@ -68,10 +68,6 @@
 import org.opensearch.search.aggregations.bucket.filter.FiltersAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.filter.ParsedFilter;
 import org.opensearch.search.aggregations.bucket.filter.ParsedFilters;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoHashGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.GeoTileGridAggregationBuilder;
-import org.opensearch.search.aggregations.bucket.geogrid.ParsedGeoHashGrid;
-import org.opensearch.search.aggregations.bucket.geogrid.ParsedGeoTileGrid;
 import org.opensearch.search.aggregations.bucket.global.GlobalAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.global.ParsedGlobal;
 import org.opensearch.search.aggregations.bucket.histogram.AutoDateHistogramAggregationBuilder;
@@ -101,21 +97,24 @@
 import org.opensearch.search.aggregations.bucket.terms.DoubleTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.LongTerms;
+import org.opensearch.search.aggregations.bucket.terms.MultiTermsAggregationBuilder;
 import org.opensearch.search.aggregations.bucket.terms.ParsedDoubleTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedLongRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedLongTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedMultiTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedSignificantLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedSignificantStringTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedStringRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.ParsedStringTerms;
+import org.opensearch.search.aggregations.bucket.terms.ParsedUnsignedLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantLongTerms;
 import org.opensearch.search.aggregations.bucket.terms.SignificantStringTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringRareTerms;
 import org.opensearch.search.aggregations.bucket.terms.StringTerms;
+import org.opensearch.search.aggregations.bucket.terms.UnsignedLongTerms;
 import org.opensearch.search.aggregations.metrics.AvgAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.CardinalityAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.ExtendedStatsAggregationBuilder;
-import org.opensearch.search.aggregations.metrics.GeoBoundsAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.GeoCentroidAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.InternalHDRPercentiles;
@@ -127,7 +126,6 @@
 import org.opensearch.search.aggregations.metrics.ParsedAvg;
 import org.opensearch.search.aggregations.metrics.ParsedCardinality;
 import org.opensearch.search.aggregations.metrics.ParsedExtendedStats;
-import org.opensearch.search.aggregations.metrics.ParsedGeoBounds;
 import org.opensearch.search.aggregations.metrics.ParsedGeoCentroid;
 import org.opensearch.search.aggregations.metrics.ParsedHDRPercentileRanks;
 import org.opensearch.search.aggregations.metrics.ParsedHDRPercentiles;
@@ -181,7 +179,7 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
-import static org.opensearch.common.xcontent.XContentHelper.toXContent;
+import static org.opensearch.core.xcontent.XContentHelper.toXContent;
 import static org.opensearch.search.aggregations.InternalMultiBucketAggregation.countInnerBucket;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
@@ -259,7 +257,6 @@ public ReduceContext forFinalReduction() {
         map.put(StatsBucketPipelineAggregationBuilder.NAME, (p, c) -> ParsedStatsBucket.fromXContent(p, (String) c));
         map.put(ExtendedStatsAggregationBuilder.NAME, (p, c) -> ParsedExtendedStats.fromXContent(p, (String) c));
         map.put(ExtendedStatsBucketPipelineAggregationBuilder.NAME, (p, c) -> ParsedExtendedStatsBucket.fromXContent(p, (String) c));
-        map.put(GeoBoundsAggregationBuilder.NAME, (p, c) -> ParsedGeoBounds.fromXContent(p, (String) c));
         map.put(GeoCentroidAggregationBuilder.NAME, (p, c) -> ParsedGeoCentroid.fromXContent(p, (String) c));
         map.put(HistogramAggregationBuilder.NAME, (p, c) -> ParsedHistogram.fromXContent(p, (String) c));
         map.put(DateHistogramAggregationBuilder.NAME, (p, c) -> ParsedDateHistogram.fromXContent(p, (String) c));
@@ -267,6 +264,7 @@ public ReduceContext forFinalReduction() {
         map.put(VariableWidthHistogramAggregationBuilder.NAME, (p, c) -> ParsedVariableWidthHistogram.fromXContent(p, (String) c));
         map.put(StringTerms.NAME, (p, c) -> ParsedStringTerms.fromXContent(p, (String) c));
         map.put(LongTerms.NAME, (p, c) -> ParsedLongTerms.fromXContent(p, (String) c));
+        map.put(UnsignedLongTerms.NAME, (p, c) -> ParsedUnsignedLongTerms.fromXContent(p, (String) c));
         map.put(DoubleTerms.NAME, (p, c) -> ParsedDoubleTerms.fromXContent(p, (String) c));
         map.put(LongRareTerms.NAME, (p, c) -> ParsedLongRareTerms.fromXContent(p, (String) c));
         map.put(StringRareTerms.NAME, (p, c) -> ParsedStringRareTerms.fromXContent(p, (String) c));
@@ -276,8 +274,6 @@ public ReduceContext forFinalReduction() {
         map.put(GlobalAggregationBuilder.NAME, (p, c) -> ParsedGlobal.fromXContent(p, (String) c));
         map.put(FilterAggregationBuilder.NAME, (p, c) -> ParsedFilter.fromXContent(p, (String) c));
         map.put(InternalSampler.PARSER_NAME, (p, c) -> ParsedSampler.fromXContent(p, (String) c));
-        map.put(GeoHashGridAggregationBuilder.NAME, (p, c) -> ParsedGeoHashGrid.fromXContent(p, (String) c));
-        map.put(GeoTileGridAggregationBuilder.NAME, (p, c) -> ParsedGeoTileGrid.fromXContent(p, (String) c));
         map.put(RangeAggregationBuilder.NAME, (p, c) -> ParsedRange.fromXContent(p, (String) c));
         map.put(DateRangeAggregationBuilder.NAME, (p, c) -> ParsedDateRange.fromXContent(p, (String) c));
         map.put(GeoDistanceAggregationBuilder.NAME, (p, c) -> ParsedGeoDistance.fromXContent(p, (String) c));
@@ -289,6 +285,7 @@ public ReduceContext forFinalReduction() {
         map.put(IpRangeAggregationBuilder.NAME, (p, c) -> ParsedBinaryRange.fromXContent(p, (String) c));
         map.put(TopHitsAggregationBuilder.NAME, (p, c) -> ParsedTopHits.fromXContent(p, (String) c));
         map.put(CompositeAggregationBuilder.NAME, (p, c) -> ParsedComposite.fromXContent(p, (String) c));
+        map.put(MultiTermsAggregationBuilder.NAME, (p, c) -> ParsedMultiTerms.fromXContent(p, (String) c));
 
         namedXContents = map.entrySet()
             .stream()
diff --git a/test/framework/src/main/java/org/opensearch/test/InternalTestCluster.java b/test/framework/src/main/java/org/opensearch/test/InternalTestCluster.java
index 3a28ec2efdd4b..2424033ee338a 100644
--- a/test/framework/src/main/java/org/opensearch/test/InternalTestCluster.java
+++ b/test/framework/src/main/java/org/opensearch/test/InternalTestCluster.java
@@ -31,14 +31,12 @@
 
 package org.opensearch.test;
 
-import com.carrotsearch.hppc.ObjectLongMap;
-import com.carrotsearch.hppc.cursors.IntObjectCursor;
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import com.carrotsearch.randomizedtesting.RandomizedTest;
 import com.carrotsearch.randomizedtesting.SeedUtils;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.store.AlreadyClosedException;
@@ -55,13 +53,13 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.action.index.MappingUpdatedAction;
 import org.opensearch.cluster.coordination.ClusterBootstrapService;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.RepositoriesMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.routing.IndexRoutingTable;
-import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.OperationRouting;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
@@ -69,30 +67,32 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Randomness;
-import org.opensearch.common.Strings;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.component.LifecycleListener;
-import org.opensearch.common.io.FileSystemUtils;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasables;
+import org.opensearch.common.lifecycle.LifecycleListener;
 import org.opensearch.common.settings.MockSecureSettings;
 import org.opensearch.common.settings.SecureSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.settings.Settings.Builder;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.FutureUtils;
+import org.opensearch.common.util.concurrent.OpenSearchExecutors;
 import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.util.FileSystemUtils;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.ShardLockObtainFailedException;
 import org.opensearch.http.HttpServerTransport;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexingPressure;
 import org.opensearch.index.engine.DocIdSeqNoAndSource;
@@ -103,9 +103,7 @@
 import org.opensearch.index.seqno.SequenceNumbers;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardTestCase;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.IndicesService;
-import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.recovery.RecoverySettings;
@@ -155,26 +153,26 @@
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.TEST_NIGHTLY;
-import static org.apache.lucene.tests.util.LuceneTestCase.rarely;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
 import static org.opensearch.common.unit.TimeValue.timeValueSeconds;
 import static org.opensearch.discovery.DiscoveryModule.DISCOVERY_TYPE_SETTING;
 import static org.opensearch.discovery.DiscoveryModule.ZEN2_DISCOVERY_TYPE;
 import static org.opensearch.discovery.FileBasedSeedHostsProvider.UNICAST_HOSTS_FILE;
-import static org.opensearch.test.OpenSearchTestCase.assertBusy;
-import static org.opensearch.test.OpenSearchTestCase.randomFrom;
 import static org.opensearch.test.NodeRoles.dataOnlyNode;
-import static org.opensearch.test.NodeRoles.masterOnlyNode;
 import static org.opensearch.test.NodeRoles.noRoles;
 import static org.opensearch.test.NodeRoles.onlyRole;
+import static org.opensearch.test.NodeRoles.onlyRoles;
 import static org.opensearch.test.NodeRoles.removeRoles;
+import static org.opensearch.test.OpenSearchTestCase.assertBusy;
+import static org.opensearch.test.OpenSearchTestCase.randomFrom;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
+import static org.apache.lucene.tests.util.LuceneTestCase.TEST_NIGHTLY;
+import static org.apache.lucene.tests.util.LuceneTestCase.rarely;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
@@ -200,16 +198,35 @@ public final class InternalTestCluster extends TestCluster {
         nodeAndClient.node.settings()
     );
 
-    private static final Predicate<NodeAndClient> NO_DATA_NO_MASTER_PREDICATE = nodeAndClient -> DiscoveryNode.isMasterNode(
-        nodeAndClient.node.settings()
-    ) == false && DiscoveryNode.isDataNode(nodeAndClient.node.settings()) == false;
+    private static final Predicate<NodeAndClient> SEARCH_NODE_PREDICATE = nodeAndClient -> DiscoveryNode.hasRole(
+        nodeAndClient.node.settings(),
+        DiscoveryNodeRole.SEARCH_ROLE
+    );
+
+    private static final Predicate<NodeAndClient> SEARCH_AND_DATA_NODE_PREDICATE = nodeAndClient -> DiscoveryNode.hasRole(
+        nodeAndClient.node.settings(),
+        DiscoveryNodeRole.SEARCH_ROLE
+    ) && DiscoveryNode.isDataNode(nodeAndClient.node.settings());
+
+    private static final Predicate<NodeAndClient> NO_DATA_NO_CLUSTER_MANAGER_PREDICATE = nodeAndClient -> DiscoveryNode
+        .isClusterManagerNode(nodeAndClient.node.settings()) == false
+        && DiscoveryNode.isDataNode(nodeAndClient.node.settings()) == false;
 
-    private static final Predicate<NodeAndClient> MASTER_NODE_PREDICATE = nodeAndClient -> DiscoveryNode.isMasterNode(
+    private static final Predicate<NodeAndClient> CLUSTER_MANAGER_NODE_PREDICATE = nodeAndClient -> DiscoveryNode.isClusterManagerNode(
         nodeAndClient.node.settings()
     );
 
-    public static final int DEFAULT_LOW_NUM_MASTER_NODES = 1;
-    public static final int DEFAULT_HIGH_NUM_MASTER_NODES = 3;
+    private static final ByteSizeValue DEFAULT_SEARCH_CACHE_SIZE = new ByteSizeValue(2, ByteSizeUnit.GB);
+
+    public static final int DEFAULT_LOW_NUM_CLUSTER_MANAGER_NODES = 1;
+    public static final int DEFAULT_HIGH_NUM_CLUSTER_MANAGER_NODES = 3;
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #DEFAULT_LOW_NUM_CLUSTER_MANAGER_NODES} */
+    @Deprecated
+    public static final int DEFAULT_LOW_NUM_MASTER_NODES = DEFAULT_LOW_NUM_CLUSTER_MANAGER_NODES;
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #DEFAULT_HIGH_NUM_CLUSTER_MANAGER_NODES} */
+    @Deprecated
+    public static final int DEFAULT_HIGH_NUM_MASTER_NODES = DEFAULT_HIGH_NUM_CLUSTER_MANAGER_NODES;
 
     static final int DEFAULT_MIN_NUM_DATA_NODES = 1;
     static final int DEFAULT_MAX_NUM_DATA_NODES = TEST_NIGHTLY ? 6 : 3;
@@ -238,8 +255,8 @@ public final class InternalTestCluster extends TestCluster {
      * fully shared cluster to be more reproducible */
     private final long[] sharedNodesSeeds;
 
-    // if set to 0, data nodes will also assume the master role
-    private final int numSharedDedicatedMasterNodes;
+    // if set to 0, data nodes will also assume the cluster-manager role
+    private final int numSharedDedicatedClusterManagerNodes;
 
     private final int numSharedDataNodes;
 
@@ -249,7 +266,7 @@ public final class InternalTestCluster extends TestCluster {
 
     private final ExecutorService executor;
 
-    private final boolean autoManageMasterNodes;
+    private final boolean autoManageClusterManagerNodes;
 
     private final Collection<Class<? extends Plugin>> mockPlugins;
 
@@ -266,13 +283,13 @@ public final class InternalTestCluster extends TestCluster {
     private ServiceDisruptionScheme activeDisruptionScheme;
     private final Function<Client, Client> clientWrapper;
 
-    private int bootstrapMasterNodeIndex = -1;
+    private int bootstrapClusterManagerNodeIndex = -1;
 
     public InternalTestCluster(
         final long clusterSeed,
         final Path baseDir,
-        final boolean randomlyAddDedicatedMasters,
-        final boolean autoManageMasterNodes,
+        final boolean randomlyAddDedicatedClusterManagers,
+        final boolean autoManageClusterManagerNodes,
         final int minNumDataNodes,
         final int maxNumDataNodes,
         final String clusterName,
@@ -285,8 +302,8 @@ public InternalTestCluster(
         this(
             clusterSeed,
             baseDir,
-            randomlyAddDedicatedMasters,
-            autoManageMasterNodes,
+            randomlyAddDedicatedClusterManagers,
+            autoManageClusterManagerNodes,
             minNumDataNodes,
             maxNumDataNodes,
             clusterName,
@@ -302,8 +319,8 @@ public InternalTestCluster(
     public InternalTestCluster(
         final long clusterSeed,
         final Path baseDir,
-        final boolean randomlyAddDedicatedMasters,
-        final boolean autoManageMasterNodes,
+        final boolean randomlyAddDedicatedClusterManagers,
+        final boolean autoManageClusterManagerNodes,
         final int minNumDataNodes,
         final int maxNumDataNodes,
         final String clusterName,
@@ -315,7 +332,7 @@ public InternalTestCluster(
         final boolean forbidPrivateIndexSettings
     ) {
         super(clusterSeed);
-        this.autoManageMasterNodes = autoManageMasterNodes;
+        this.autoManageClusterManagerNodes = autoManageClusterManagerNodes;
         this.clientWrapper = clientWrapper;
         this.forbidPrivateIndexSettings = forbidPrivateIndexSettings;
         this.baseDir = baseDir;
@@ -330,24 +347,24 @@ public InternalTestCluster(
 
         Random random = new Random(clusterSeed);
 
-        boolean useDedicatedMasterNodes = randomlyAddDedicatedMasters ? random.nextBoolean() : false;
+        boolean useDedicatedClusterManagerNodes = randomlyAddDedicatedClusterManagers ? random.nextBoolean() : false;
 
         this.numSharedDataNodes = RandomNumbers.randomIntBetween(random, minNumDataNodes, maxNumDataNodes);
         assert this.numSharedDataNodes >= 0;
 
         if (numSharedDataNodes == 0) {
             this.numSharedCoordOnlyNodes = 0;
-            this.numSharedDedicatedMasterNodes = 0;
+            this.numSharedDedicatedClusterManagerNodes = 0;
         } else {
-            if (useDedicatedMasterNodes) {
+            if (useDedicatedClusterManagerNodes) {
                 if (random.nextBoolean()) {
-                    // use a dedicated master, but only low number to reduce overhead to tests
-                    this.numSharedDedicatedMasterNodes = DEFAULT_LOW_NUM_MASTER_NODES;
+                    // use a dedicated cluster-manager, but only low number to reduce overhead to tests
+                    this.numSharedDedicatedClusterManagerNodes = DEFAULT_LOW_NUM_CLUSTER_MANAGER_NODES;
                 } else {
-                    this.numSharedDedicatedMasterNodes = DEFAULT_HIGH_NUM_MASTER_NODES;
+                    this.numSharedDedicatedClusterManagerNodes = DEFAULT_HIGH_NUM_CLUSTER_MANAGER_NODES;
                 }
             } else {
-                this.numSharedDedicatedMasterNodes = 0;
+                this.numSharedDedicatedClusterManagerNodes = 0;
             }
             if (numClientNodes < 0) {
                 this.numSharedCoordOnlyNodes = RandomNumbers.randomIntBetween(
@@ -367,20 +384,20 @@ public InternalTestCluster(
 
         this.mockPlugins = mockPlugins;
 
-        sharedNodesSeeds = new long[numSharedDedicatedMasterNodes + numSharedDataNodes + numSharedCoordOnlyNodes];
+        sharedNodesSeeds = new long[numSharedDedicatedClusterManagerNodes + numSharedDataNodes + numSharedCoordOnlyNodes];
         for (int i = 0; i < sharedNodesSeeds.length; i++) {
             sharedNodesSeeds[i] = random.nextLong();
         }
 
         logger.info(
-            "Setup InternalTestCluster [{}] with seed [{}] using [{}] dedicated masters, "
-                + "[{}] (data) nodes and [{}] coord only nodes (min_master_nodes are [{}])",
+            "Setup InternalTestCluster [{}] with seed [{}] using [{}] dedicated cluster-managers, "
+                + "[{}] (data) nodes and [{}] coord only nodes (min_cluster_manager_nodes are [{}])",
             clusterName,
             SeedUtils.formatSeed(clusterSeed),
-            numSharedDedicatedMasterNodes,
+            numSharedDedicatedClusterManagerNodes,
             numSharedDataNodes,
             numSharedCoordOnlyNodes,
-            autoManageMasterNodes ? "auto-managed" : "manual"
+            autoManageClusterManagerNodes ? "auto-managed" : "manual"
         );
         this.nodeConfigurationSource = nodeConfigurationSource;
         numDataPaths = random.nextInt(5) == 0 ? 2 + random.nextInt(3) : 1;
@@ -433,9 +450,9 @@ public InternalTestCluster(
             RecoverySettings.INDICES_RECOVERY_MAX_CONCURRENT_OPERATIONS_SETTING.getKey(),
             RandomNumbers.randomIntBetween(random, 1, 4)
         );
-        // TODO: currently we only randomize "cluster.no_master_block" between "write" and "metadata_write", as "all" is fragile
-        // and fails shards when a master abdicates, which breaks many tests.
-        builder.put(NoMasterBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), randomFrom(random, "write", "metadata_write"));
+        // TODO: currently we only randomize "cluster.no_cluster_manager_block" between "write" and "metadata_write", as "all" is fragile
+        // and fails shards when a cluster-manager abdicates, which breaks many tests.
+        builder.put(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_SETTING.getKey(), randomFrom(random, "write", "metadata_write"));
         defaultSettings = builder.build();
         executor = OpenSearchExecutors.newScaling(
             "internal_test_cluster_executor",
@@ -449,14 +466,15 @@ public InternalTestCluster(
     }
 
     /**
-     * Sets {@link #bootstrapMasterNodeIndex} to the given value, see {@link #bootstrapMasterNodeWithSpecifiedIndex(List)}
+     * Sets {@link #bootstrapClusterManagerNodeIndex} to the given value, see {@link #bootstrapClusterManagerNodeWithSpecifiedIndex(List)}
      * for the description of how this field is used.
-     * It's only possible to change {@link #bootstrapMasterNodeIndex} value if autoManageMasterNodes is false.
+     * It's only possible to change {@link #bootstrapClusterManagerNodeIndex} value if autoManageClusterManagerNodes is false.
      */
-    public void setBootstrapMasterNodeIndex(int bootstrapMasterNodeIndex) {
-        assert autoManageMasterNodes == false || bootstrapMasterNodeIndex == -1
-            : "bootstrapMasterNodeIndex should be -1 if autoManageMasterNodes is true, but was " + bootstrapMasterNodeIndex;
-        this.bootstrapMasterNodeIndex = bootstrapMasterNodeIndex;
+    public void setBootstrapClusterManagerNodeIndex(int bootstrapClusterManagerNodeIndex) {
+        assert autoManageClusterManagerNodes == false || bootstrapClusterManagerNodeIndex == -1
+            : "bootstrapClusterManagerNodeIndex should be -1 if autoManageClusterManagerNodes is true, but was "
+                + bootstrapClusterManagerNodeIndex;
+        this.bootstrapClusterManagerNodeIndex = bootstrapClusterManagerNodeIndex;
     }
 
     @Override
@@ -648,7 +666,7 @@ public synchronized void ensureAtLeastNumDataNodes(int n) {
         int size = numDataNodes();
         if (size < n) {
             logger.info("increasing cluster size from {} to {}", size, n);
-            if (numSharedDedicatedMasterNodes > 0) {
+            if (numSharedDedicatedClusterManagerNodes > 0) {
                 startDataOnlyNodes(n - size);
             } else {
                 startNodes(n - size);
@@ -657,6 +675,39 @@ public synchronized void ensureAtLeastNumDataNodes(int n) {
         }
     }
 
+    /**
+     * Ensures that at least <code>n</code> search nodes are present in the cluster.
+     * if more nodes than <code>n</code> are present this method will not
+     * stop any of the running nodes.
+     */
+    public synchronized void ensureAtLeastNumSearchNodes(int n) {
+        int size = numSearchNodes();
+        if (size < n) {
+            logger.info("increasing cluster size from {} to {}", size, n);
+            startNodes(n - size, Settings.builder().put(onlyRole(Settings.EMPTY, DiscoveryNodeRole.SEARCH_ROLE)).build());
+            validateClusterFormed();
+        }
+    }
+
+    /**
+     * Ensures that at least <code>n</code> data-search nodes are present in the cluster.
+     * if more nodes than <code>n</code> are present this method will not
+     * stop any of the running nodes.
+     */
+    public synchronized void ensureAtLeastNumSearchAndDataNodes(int n) {
+        int size = numSearchAndDataNodes();
+        if (size < n) {
+            logger.info("increasing cluster size from {} to {}", size, n);
+            Set<DiscoveryNodeRole> searchAndDataRoles = Set.of(DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.SEARCH_ROLE);
+            Settings settings = Settings.builder()
+                .put(Settings.EMPTY)
+                .put(Node.NODE_SEARCH_CACHE_SIZE_SETTING.getKey(), DEFAULT_SEARCH_CACHE_SIZE)
+                .build();
+            startNodes(n - size, Settings.builder().put(onlyRoles(settings, searchAndDataRoles)).build());
+            validateClusterFormed();
+        }
+    }
+
     /**
      * Ensures that at most <code>n</code> are up and running.
      * If less nodes that <code>n</code> are running this method
@@ -667,10 +718,10 @@ public synchronized void ensureAtMostNumDataNodes(int n) throws IOException {
         if (size <= n) {
             return;
         }
-        // prevent killing the master if possible and client nodes
+        // prevent killing the cluster-manager if possible and client nodes
         final Stream<NodeAndClient> collection = n == 0
             ? nodes.values().stream()
-            : nodes.values().stream().filter(DATA_NODE_PREDICATE.and(new NodeNamePredicate(getMasterName()).negate()));
+            : nodes.values().stream().filter(DATA_NODE_PREDICATE.and(new NodeNamePredicate(getClusterManagerName()).negate()));
         final Iterator<NodeAndClient> values = collection.iterator();
 
         logger.info("changing cluster size from {} data nodes to {}", size, n);
@@ -687,7 +738,12 @@ public synchronized void ensureAtMostNumDataNodes(int n) throws IOException {
         }
     }
 
-    private Settings getNodeSettings(final int nodeId, final long seed, final Settings extraSettings, final int defaultMinMasterNodes) {
+    private Settings getNodeSettings(
+        final int nodeId,
+        final long seed,
+        final Settings extraSettings,
+        final int defaultMinClusterManagerNodes
+    ) {
         final Settings settings = getSettings(nodeId, seed, extraSettings);
 
         final String name = buildNodeName(nodeId, settings);
@@ -718,9 +774,9 @@ private Settings getNodeSettings(final int nodeId, final long seed, final Settin
         final String discoveryType = DISCOVERY_TYPE_SETTING.get(updatedSettings.build());
         final boolean usingSingleNodeDiscovery = discoveryType.equals("single-node");
         if (usingSingleNodeDiscovery == false) {
-            if (autoManageMasterNodes) {
+            if (autoManageClusterManagerNodes) {
                 assertThat(
-                    "if master nodes are automatically managed then nodes must complete a join cycle when starting",
+                    "if cluster-manager nodes are automatically managed then nodes must complete a join cycle when starting",
                     updatedSettings.get(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey()),
                     nullValue()
                 );
@@ -787,13 +843,13 @@ private static String getRoleSuffix(Settings settings) {
         String suffix = "";
         // only add the suffixes if roles are explicitly defined
         if (settings.hasValue("nodes.roles")) {
-            if (DiscoveryNode.isMasterNode(settings)) {
+            if (DiscoveryNode.isClusterManagerNode(settings)) {
                 suffix = suffix + DiscoveryNodeRole.CLUSTER_MANAGER_ROLE.roleNameAbbreviation();
             }
             if (DiscoveryNode.isDataNode(settings)) {
                 suffix = suffix + DiscoveryNodeRole.DATA_ROLE.roleNameAbbreviation();
             }
-            if (!DiscoveryNode.isMasterNode(settings) && !DiscoveryNode.isDataNode(settings)) {
+            if (!DiscoveryNode.isClusterManagerNode(settings) && !DiscoveryNode.isDataNode(settings)) {
                 suffix = suffix + "c";
             }
         }
@@ -817,26 +873,45 @@ public Client dataNodeClient() {
     }
 
     /**
-     * Returns a node client to the current master node.
+     * Returns a node client to the current cluster-manager node.
      * Note: use this with care tests should not rely on a certain nodes client.
      */
-    public Client masterClient() {
-        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getMasterName()));
+    public Client clusterManagerClient() {
+        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getClusterManagerName()));
         if (randomNodeAndClient != null) {
-            return randomNodeAndClient.nodeClient(); // ensure node client master is requested
+            return randomNodeAndClient.nodeClient(); // ensure node client cluster-manager is requested
         }
-        throw new AssertionError("No master client found");
+        throw new AssertionError("No cluster-manager client found");
     }
 
     /**
-     * Returns a node client to random node but not the master. This method will fail if no non-master client is available.
+     * Returns a node client to random node but not the cluster-manager. This method will fail if no non-cluster-manager client is available.
      */
-    public Client nonMasterClient() {
-        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getMasterName()).negate());
+    public Client nonClusterManagerClient() {
+        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getClusterManagerName()).negate());
         if (randomNodeAndClient != null) {
-            return randomNodeAndClient.nodeClient(); // ensure node client non-master is requested
+            return randomNodeAndClient.nodeClient(); // ensure node client non-cluster-manager is requested
         }
-        throw new AssertionError("No non-master client found");
+        throw new AssertionError("No non-cluster-manager client found");
+    }
+
+    /**
+     * Returns a node client to the current cluster-manager node.
+     * Note: use this with care tests should not rely on a certain nodes client.
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerClient()}
+     */
+    @Deprecated
+    public Client masterClient() {
+        return clusterManagerClient();
+    }
+
+    /**
+     * Returns a node client to random node but not the cluster-manager. This method will fail if no non-cluster-manager client is available.
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #nonClusterManagerClient()}
+     */
+    @Deprecated
+    public Client nonMasterClient() {
+        return nonClusterManagerClient();
     }
 
     /**
@@ -844,14 +919,14 @@ public Client nonMasterClient() {
      */
     public synchronized Client coordOnlyNodeClient() {
         ensureOpen();
-        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(NO_DATA_NO_MASTER_PREDICATE);
+        NodeAndClient randomNodeAndClient = getRandomNodeAndClient(NO_DATA_NO_CLUSTER_MANAGER_PREDICATE);
         if (randomNodeAndClient != null) {
             return randomNodeAndClient.client();
         }
         int nodeId = nextNodeId.getAndIncrement();
         Settings settings = getSettings(nodeId, random.nextLong(), Settings.EMPTY);
         startCoordinatingOnlyNode(settings);
-        return getRandomNodeAndClient(NO_DATA_NO_MASTER_PREDICATE).client();
+        return getRandomNodeAndClient(NO_DATA_NO_CLUSTER_MANAGER_PREDICATE).client();
     }
 
     public synchronized String startCoordinatingOnlyNode(Settings settings) {
@@ -897,7 +972,10 @@ public synchronized void close() throws IOException {
         }
     }
 
-    public static final int REMOVED_MINIMUM_MASTER_NODES = Integer.MAX_VALUE;
+    public static final int REMOVED_MINIMUM_CLUSTER_MANAGER_NODES = Integer.MAX_VALUE;
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #REMOVED_MINIMUM_CLUSTER_MANAGER_NODES} */
+    @Deprecated
+    public static final int REMOVED_MINIMUM_MASTER_NODES = REMOVED_MINIMUM_CLUSTER_MANAGER_NODES;
 
     private final class NodeAndClient implements Closeable {
         private MockNode node;
@@ -930,8 +1008,14 @@ public String getName() {
             return name;
         }
 
+        public boolean isClusterManagerEligible() {
+            return DiscoveryNode.isClusterManagerNode(node.settings());
+        }
+
+        /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #isClusterManagerEligible()} */
+        @Deprecated
         public boolean isMasterEligible() {
-            return DiscoveryNode.isMasterNode(node.settings());
+            return isClusterManagerEligible();
         }
 
         Client client() {
@@ -981,7 +1065,7 @@ void startNode() {
         /**
          * closes the node and prepares it to be restarted
          */
-        Settings closeForRestart(RestartCallback callback, int minMasterNodes) throws Exception {
+        Settings closeForRestart(RestartCallback callback, int minClusterManagerNodes) throws Exception {
             assert callback != null;
             close();
             removeNode(this);
@@ -989,7 +1073,7 @@ Settings closeForRestart(RestartCallback callback, int minMasterNodes) throws Ex
             assert callbackSettings != null;
             Settings.Builder newSettings = Settings.builder();
             newSettings.put(callbackSettings);
-            if (minMasterNodes >= 0) {
+            if (minClusterManagerNodes >= 0) {
                 if (INITIAL_CLUSTER_MANAGER_NODES_SETTING.exists(callbackSettings) == false) {
                     newSettings.putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey());
                 }
@@ -1121,61 +1205,63 @@ private synchronized void reset(boolean wipeData) throws IOException {
         }
 
         assertTrue(
-            "expected at least one master-eligible node left in " + nodes,
-            nodes.isEmpty() || nodes.values().stream().anyMatch(NodeAndClient::isMasterEligible)
+            "expected at least one cluster-manager-eligible node left in " + nodes,
+            nodes.isEmpty() || nodes.values().stream().anyMatch(NodeAndClient::isClusterManagerEligible)
         );
 
         final int prevNodeCount = nodes.size();
 
         // start any missing node
-        assert newSize == numSharedDedicatedMasterNodes + numSharedDataNodes + numSharedCoordOnlyNodes;
-        final int numberOfMasterNodes = numSharedDedicatedMasterNodes > 0 ? numSharedDedicatedMasterNodes : numSharedDataNodes;
-        final int defaultMinMasterNodes = (numberOfMasterNodes / 2) + 1;
+        assert newSize == numSharedDedicatedClusterManagerNodes + numSharedDataNodes + numSharedCoordOnlyNodes;
+        final int numberOfClusterManagerNodes = numSharedDedicatedClusterManagerNodes > 0
+            ? numSharedDedicatedClusterManagerNodes
+            : numSharedDataNodes;
+        final int defaultMinClusterManagerNodes = (numberOfClusterManagerNodes / 2) + 1;
         final List<NodeAndClient> toStartAndPublish = new ArrayList<>(); // we want to start nodes in one go
         final Runnable onTransportServiceStarted = () -> rebuildUnicastHostFiles(toStartAndPublish);
 
         final List<Settings> settings = new ArrayList<>();
 
-        for (int i = 0; i < numSharedDedicatedMasterNodes; i++) {
-            final Settings nodeSettings = getNodeSettings(i, sharedNodesSeeds[i], Settings.EMPTY, defaultMinMasterNodes);
+        for (int i = 0; i < numSharedDedicatedClusterManagerNodes; i++) {
+            final Settings nodeSettings = getNodeSettings(i, sharedNodesSeeds[i], Settings.EMPTY, defaultMinClusterManagerNodes);
             settings.add(removeRoles(nodeSettings, Collections.singleton(DiscoveryNodeRole.DATA_ROLE)));
         }
-        for (int i = numSharedDedicatedMasterNodes; i < numSharedDedicatedMasterNodes + numSharedDataNodes; i++) {
-            final Settings nodeSettings = getNodeSettings(i, sharedNodesSeeds[i], Settings.EMPTY, defaultMinMasterNodes);
-            if (numSharedDedicatedMasterNodes > 0) {
+        for (int i = numSharedDedicatedClusterManagerNodes; i < numSharedDedicatedClusterManagerNodes + numSharedDataNodes; i++) {
+            final Settings nodeSettings = getNodeSettings(i, sharedNodesSeeds[i], Settings.EMPTY, defaultMinClusterManagerNodes);
+            if (numSharedDedicatedClusterManagerNodes > 0) {
                 settings.add(removeRoles(nodeSettings, Collections.singleton(DiscoveryNodeRole.MASTER_ROLE)));
             } else {
-                // if we don't have dedicated master nodes, keep things default
+                // if we don't have dedicated cluster-manager nodes, keep things default
                 settings.add(nodeSettings);
             }
         }
-        for (int i = numSharedDedicatedMasterNodes + numSharedDataNodes; i < numSharedDedicatedMasterNodes + numSharedDataNodes
-            + numSharedCoordOnlyNodes; i++) {
+        for (int i = numSharedDedicatedClusterManagerNodes + numSharedDataNodes; i < numSharedDedicatedClusterManagerNodes
+            + numSharedDataNodes + numSharedCoordOnlyNodes; i++) {
             final Builder extraSettings = Settings.builder().put(noRoles());
-            settings.add(getNodeSettings(i, sharedNodesSeeds[i], extraSettings.build(), defaultMinMasterNodes));
+            settings.add(getNodeSettings(i, sharedNodesSeeds[i], extraSettings.build(), defaultMinClusterManagerNodes));
         }
 
-        int autoBootstrapMasterNodeIndex = -1;
-        final List<String> masterNodeNames = settings.stream()
-            .filter(DiscoveryNode::isMasterNode)
+        int autoBootstrapClusterManagerNodeIndex = -1;
+        final List<String> clusterManagerNodeNames = settings.stream()
+            .filter(DiscoveryNode::isClusterManagerNode)
             .map(Node.NODE_NAME_SETTING::get)
             .collect(Collectors.toList());
 
-        if (prevNodeCount == 0 && autoManageMasterNodes) {
-            if (numSharedDedicatedMasterNodes > 0) {
-                autoBootstrapMasterNodeIndex = RandomNumbers.randomIntBetween(random, 0, numSharedDedicatedMasterNodes - 1);
+        if (prevNodeCount == 0 && autoManageClusterManagerNodes) {
+            if (numSharedDedicatedClusterManagerNodes > 0) {
+                autoBootstrapClusterManagerNodeIndex = RandomNumbers.randomIntBetween(random, 0, numSharedDedicatedClusterManagerNodes - 1);
             } else if (numSharedDataNodes > 0) {
-                autoBootstrapMasterNodeIndex = RandomNumbers.randomIntBetween(random, 0, numSharedDataNodes - 1);
+                autoBootstrapClusterManagerNodeIndex = RandomNumbers.randomIntBetween(random, 0, numSharedDataNodes - 1);
             }
         }
 
-        final List<Settings> updatedSettings = bootstrapMasterNodeWithSpecifiedIndex(settings);
+        final List<Settings> updatedSettings = bootstrapClusterManagerNodeWithSpecifiedIndex(settings);
 
-        for (int i = 0; i < numSharedDedicatedMasterNodes + numSharedDataNodes + numSharedCoordOnlyNodes; i++) {
+        for (int i = 0; i < numSharedDedicatedClusterManagerNodes + numSharedDataNodes + numSharedCoordOnlyNodes; i++) {
             Settings nodeSettings = updatedSettings.get(i);
-            if (i == autoBootstrapMasterNodeIndex) {
+            if (i == autoBootstrapClusterManagerNodeIndex) {
                 nodeSettings = Settings.builder()
-                    .putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), masterNodeNames)
+                    .putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), clusterManagerNodeNames)
                     .put(nodeSettings)
                     .build();
             }
@@ -1187,7 +1273,7 @@ private synchronized void reset(boolean wipeData) throws IOException {
 
         nextNodeId.set(newSize);
         assert size() == newSize;
-        if (autoManageMasterNodes && newSize > 0) {
+        if (autoManageClusterManagerNodes && newSize > 0) {
             validateClusterFormed();
         }
         logger.debug(
@@ -1214,11 +1300,14 @@ public synchronized void validateClusterFormed() {
                     .map(ClusterService::state)
                     .collect(Collectors.toList());
                 final String debugString = ", expected nodes: " + expectedNodes + " and actual cluster states " + states;
-                // all nodes have a master
-                assertTrue("Missing master" + debugString, states.stream().allMatch(cs -> cs.nodes().getMasterNodeId() != null));
-                // all nodes have the same master (in same term)
+                // all nodes have a cluster-manager
+                assertTrue(
+                    "Missing cluster-manager" + debugString,
+                    states.stream().allMatch(cs -> cs.nodes().getClusterManagerNodeId() != null)
+                );
+                // all nodes have the same cluster-manager (in same term)
                 assertEquals(
-                    "Not all masters in same term" + debugString,
+                    "Not all cluster-managers in same term" + debugString,
                     1,
                     states.stream().mapToLong(ClusterState::term).distinct().count()
                 );
@@ -1230,6 +1319,12 @@ public synchronized void validateClusterFormed() {
                         assertTrue("Expected node to exist: " + expectedNode + debugString, discoveryNodes.nodeExists(expectedNode));
                     }
                 });
+                states.forEach(cs -> {
+                    if (cs.nodes().getNodes().values().stream().findFirst().get().isRemoteStoreNode()) {
+                        RepositoriesMetadata repositoriesMetadata = cs.metadata().custom(RepositoriesMetadata.TYPE);
+                        assertTrue(repositoriesMetadata != null && !repositoriesMetadata.repositories().isEmpty());
+                    }
+                });
             }, 30, TimeUnit.SECONDS);
         } catch (AssertionError ae) {
             throw new IllegalStateException("cluster failed to form", ae);
@@ -1401,15 +1496,15 @@ private IndexShard getShardOrNull(ClusterState clusterState, ShardRouting shardR
     public void assertSeqNos() throws Exception {
         assertBusy(() -> {
             final ClusterState state = clusterService().state();
-            for (ObjectObjectCursor<String, IndexRoutingTable> indexRoutingTable : state.routingTable().indicesRouting()) {
-                for (IntObjectCursor<IndexShardRoutingTable> indexShardRoutingTable : indexRoutingTable.value.shards()) {
-                    ShardRouting primaryShardRouting = indexShardRoutingTable.value.primaryShard();
+            for (final IndexRoutingTable indexRoutingTable : state.routingTable().indicesRouting().values()) {
+                for (var indexShardRoutingTable : indexRoutingTable.shards().values()) {
+                    ShardRouting primaryShardRouting = indexShardRoutingTable.primaryShard();
                     final IndexShard primaryShard = getShardOrNull(state, primaryShardRouting);
                     if (primaryShard == null) {
                         continue; // just ignore - shard movement
                     }
                     final SeqNoStats primarySeqNoStats;
-                    final ObjectLongMap<String> syncGlobalCheckpoints;
+                    final Map<String, Long> syncGlobalCheckpoints;
                     try {
                         primarySeqNoStats = primaryShard.seqNoStats();
                         syncGlobalCheckpoints = primaryShard.getInSyncGlobalCheckpoints();
@@ -1421,7 +1516,7 @@ public void assertSeqNos() throws Exception {
                         primarySeqNoStats.getGlobalCheckpoint(),
                         not(equalTo(SequenceNumbers.UNASSIGNED_SEQ_NO))
                     );
-                    for (ShardRouting replicaShardRouting : indexShardRoutingTable.value.replicaShards()) {
+                    for (ShardRouting replicaShardRouting : indexShardRoutingTable.replicaShards()) {
                         final IndexShard replicaShard = getShardOrNull(state, replicaShardRouting);
                         if (replicaShard == null) {
                             continue; // just ignore - shard movement
@@ -1434,11 +1529,13 @@ public void assertSeqNos() throws Exception {
                         }
                         assertThat(replicaShardRouting + " seq_no_stats mismatch", seqNoStats, equalTo(primarySeqNoStats));
                         // the local knowledge on the primary of the global checkpoint equals the global checkpoint on the shard
-                        assertThat(
-                            replicaShardRouting + " global checkpoint syncs mismatch",
-                            seqNoStats.getGlobalCheckpoint(),
-                            equalTo(syncGlobalCheckpoints.get(replicaShardRouting.allocationId().getId()))
-                        );
+                        if (primaryShard.isRemoteTranslogEnabled() == false) {
+                            assertThat(
+                                replicaShardRouting + " global checkpoint syncs mismatch",
+                                seqNoStats.getGlobalCheckpoint(),
+                                equalTo(syncGlobalCheckpoints.get(replicaShardRouting.allocationId().getId()))
+                            );
+                        }
                     }
                 }
             }
@@ -1451,9 +1548,9 @@ public void assertSeqNos() throws Exception {
     public void assertSameDocIdsOnShards() throws Exception {
         assertBusy(() -> {
             ClusterState state = client().admin().cluster().prepareState().get().getState();
-            for (ObjectObjectCursor<String, IndexRoutingTable> indexRoutingTable : state.routingTable().indicesRouting()) {
-                for (IntObjectCursor<IndexShardRoutingTable> indexShardRoutingTable : indexRoutingTable.value.shards()) {
-                    ShardRouting primaryShardRouting = indexShardRoutingTable.value.primaryShard();
+            for (final IndexRoutingTable indexRoutingTable : state.routingTable().indicesRouting().values()) {
+                for (var indexShardRoutingTable : indexRoutingTable.shards().values()) {
+                    ShardRouting primaryShardRouting = indexShardRoutingTable.primaryShard();
                     IndexShard primaryShard = getShardOrNull(state, primaryShardRouting);
                     if (primaryShard == null) {
                         continue;
@@ -1464,7 +1561,7 @@ public void assertSameDocIdsOnShards() throws Exception {
                     } catch (AlreadyClosedException ex) {
                         continue;
                     }
-                    for (ShardRouting replicaShardRouting : indexShardRoutingTable.value.replicaShards()) {
+                    for (ShardRouting replicaShardRouting : indexShardRoutingTable.replicaShards()) {
                         IndexShard replicaShard = getShardOrNull(state, replicaShardRouting);
                         if (replicaShard == null) {
                             continue;
@@ -1550,16 +1647,33 @@ public <T> Iterable<T> getDataNodeInstances(Class<T> clazz) {
         return getInstances(clazz, DATA_NODE_PREDICATE);
     }
 
+    public synchronized <T> T getCurrentClusterManagerNodeInstance(Class<T> clazz) {
+        return getInstance(clazz, new NodeNamePredicate(getClusterManagerName()));
+    }
+
+    /**
+     * Returns an Iterable to all instances for the given class &gt;T&lt; across all data and cluster-manager nodes
+     * in the cluster.
+     */
+    public <T> Iterable<T> getDataOrClusterManagerNodeInstances(Class<T> clazz) {
+        return getInstances(clazz, DATA_NODE_PREDICATE.or(CLUSTER_MANAGER_NODE_PREDICATE));
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getCurrentClusterManagerNodeInstance(Class)} */
+    @Deprecated
     public synchronized <T> T getCurrentMasterNodeInstance(Class<T> clazz) {
-        return getInstance(clazz, new NodeNamePredicate(getMasterName()));
+        return getCurrentClusterManagerNodeInstance(clazz);
     }
 
     /**
-     * Returns an Iterable to all instances for the given class &gt;T&lt; across all data and master nodes
+     * Returns an Iterable to all instances for the given class &gt;T&lt; across all data and cluster-manager nodes
      * in the cluster.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getDataOrClusterManagerNodeInstances(Class)}
      */
+    @Deprecated
     public <T> Iterable<T> getDataOrMasterNodeInstances(Class<T> clazz) {
-        return getInstances(clazz, DATA_NODE_PREDICATE.or(MASTER_NODE_PREDICATE));
+        return getDataOrClusterManagerNodeInstances(clazz);
     }
 
     private <T> Iterable<T> getInstances(Class<T> clazz, Predicate<NodeAndClient> predicate) {
@@ -1582,8 +1696,14 @@ public <T> T getDataNodeInstance(Class<T> clazz) {
         return getInstance(clazz, DATA_NODE_PREDICATE);
     }
 
+    public <T> T getClusterManagerNodeInstance(Class<T> clazz) {
+        return getInstance(clazz, CLUSTER_MANAGER_NODE_PREDICATE);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerNodeInstance(Class)} */
+    @Deprecated
     public <T> T getMasterNodeInstance(Class<T> clazz) {
-        return getInstance(clazz, MASTER_NODE_PREDICATE);
+        return getClusterManagerNodeInstance(clazz);
     }
 
     private synchronized <T> T getInstance(Class<T> clazz, Predicate<NodeAndClient> predicate) {
@@ -1628,6 +1748,20 @@ public InetSocketAddress[] httpAddresses() {
         return addresses.toArray(new InetSocketAddress[addresses.size()]);
     }
 
+    /**
+     * Stops a random search node in the cluster. Returns true if a node was found to stop, false otherwise.
+     */
+    public synchronized boolean stopRandomSearchNode() throws IOException {
+        ensureOpen();
+        NodeAndClient nodeAndClient = getRandomNodeAndClient(SEARCH_NODE_PREDICATE);
+        if (nodeAndClient != null) {
+            logger.info("Closing random node [{}] ", nodeAndClient.name);
+            stopNodesAndClient(nodeAndClient);
+            return true;
+        }
+        return false;
+    }
+
     /**
      * Stops a random data node in the cluster. Returns true if a node was found to stop, false otherwise.
      */
@@ -1652,14 +1786,14 @@ public synchronized void stopRandomNode(final Predicate<Settings> filter) throws
         if (nodeAndClient != null) {
             if (nodePrefix.equals(OpenSearchIntegTestCase.SUITE_CLUSTER_NODE_PREFIX)
                 && nodeAndClient.nodeAndClientId() < sharedNodesSeeds.length
-                && nodeAndClient.isMasterEligible()
-                && autoManageMasterNodes
+                && nodeAndClient.isClusterManagerEligible()
+                && autoManageClusterManagerNodes
                 && nodes.values()
                     .stream()
-                    .filter(NodeAndClient::isMasterEligible)
+                    .filter(NodeAndClient::isClusterManagerEligible)
                     .filter(n -> n.nodeAndClientId() < sharedNodesSeeds.length)
                     .count() == 1) {
-                throw new AssertionError("Tried to stop the only master eligible shared node");
+                throw new AssertionError("Tried to stop the only cluster-manager eligible shared node");
             }
             logger.info("Closing filtered random node [{}] ", nodeAndClient.name);
             stopNodesAndClient(nodeAndClient);
@@ -1667,36 +1801,81 @@ public synchronized void stopRandomNode(final Predicate<Settings> filter) throws
     }
 
     /**
-     * Stops the current master node forcefully
+     * Stops the current cluster-manager node forcefully.
      */
-    public synchronized void stopCurrentMasterNode() throws IOException {
+    public synchronized void stopCurrentClusterManagerNode() throws IOException {
         ensureOpen();
         assert size() > 0;
-        String masterNodeName = getMasterName();
-        final NodeAndClient masterNode = nodes.get(masterNodeName);
-        assert masterNode != null;
-        logger.info("Closing master node [{}] ", masterNodeName);
-        stopNodesAndClient(masterNode);
+        String clusterManagerNodeName = getClusterManagerName();
+        final NodeAndClient clusterManagerNode = nodes.get(clusterManagerNodeName);
+        assert clusterManagerNode != null;
+        logger.info("Closing cluster-manager node [{}] ", clusterManagerNodeName);
+        stopNodesAndClient(clusterManagerNode);
     }
 
     /**
-     * Stops any of the current nodes but not the master node.
+     * Stops any of the current nodes but not the cluster-manager node.
      */
-    public synchronized void stopRandomNonMasterNode() throws IOException {
-        NodeAndClient nodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getMasterName()).negate());
+    public synchronized void stopRandomNonClusterManagerNode() throws IOException {
+        NodeAndClient nodeAndClient = getRandomNodeAndClient(new NodeNamePredicate(getClusterManagerName()).negate());
         if (nodeAndClient != null) {
-            logger.info("Closing random non master node [{}] current master [{}] ", nodeAndClient.name, getMasterName());
+            logger.info(
+                "Closing random non cluster-manager node [{}] current cluster-manager [{}] ",
+                nodeAndClient.name,
+                getClusterManagerName()
+            );
             stopNodesAndClient(nodeAndClient);
         }
     }
 
+    /**
+     * Stops the current cluster-manager node forcefully.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #stopCurrentClusterManagerNode()}
+     */
+    @Deprecated
+    public synchronized void stopCurrentMasterNode() throws IOException {
+        stopCurrentClusterManagerNode();
+    }
+
+    /**
+     * Stops any of the current nodes but not the cluster-manager node.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #stopRandomNonClusterManagerNode()}
+     */
+    @Deprecated
+    public synchronized void stopRandomNonMasterNode() throws IOException {
+        stopRandomNonClusterManagerNode();
+    }
+
+    /**
+     * Stops all running nodes in cluster
+     */
+    public void stopAllNodes() {
+        try {
+            int totalDataNodes = numDataNodes();
+            while (totalDataNodes > 0) {
+                stopRandomDataNode();
+                totalDataNodes -= 1;
+            }
+            int totalClusterManagerNodes = numClusterManagerNodes();
+            while (totalClusterManagerNodes > 1) {
+                stopRandomNonClusterManagerNode();
+                totalClusterManagerNodes -= 1;
+            }
+            stopCurrentClusterManagerNode();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private synchronized void startAndPublishNodesAndClients(List<NodeAndClient> nodeAndClients) {
         if (nodeAndClients.size() > 0) {
-            final int newMasters = (int) nodeAndClients.stream()
-                .filter(NodeAndClient::isMasterEligible)
-                .filter(nac -> nodes.containsKey(nac.name) == false) // filter out old masters
+            final int newClusterManagers = (int) nodeAndClients.stream()
+                .filter(NodeAndClient::isClusterManagerEligible)
+                .filter(nac -> nodes.containsKey(nac.name) == false) // filter out old cluster-managers
                 .count();
-            final int currentMasters = getMasterNodesCount();
+            final int currentClusterManagers = getClusterManagerNodesCount();
             rebuildUnicastHostFiles(nodeAndClients); // ensure that new nodes can find the existing nodes when they start
             List<Future<?>> futures = nodeAndClients.stream().map(node -> executor.submit(node::startNode)).collect(Collectors.toList());
 
@@ -1713,11 +1892,11 @@ private synchronized void startAndPublishNodesAndClients(List<NodeAndClient> nod
             }
             nodeAndClients.forEach(this::publishNode);
 
-            if (autoManageMasterNodes
-                && currentMasters > 0
-                && newMasters > 0
-                && getMinMasterNodes(currentMasters + newMasters) > currentMasters) {
-                // update once masters have joined
+            if (autoManageClusterManagerNodes
+                && currentClusterManagers > 0
+                && newClusterManagers > 0
+                && getMinClusterManagerNodes(currentClusterManagers + newClusterManagers) > currentClusterManagers) {
+                // update once cluster-managers have joined
                 validateClusterFormed();
             }
         }
@@ -1735,7 +1914,7 @@ private void rebuildUnicastHostFiles(List<NodeAndClient> newNodes) {
                     .filter(Objects::nonNull)
                     .map(TransportService::getLocalNode)
                     .filter(Objects::nonNull)
-                    .filter(DiscoveryNode::isMasterNode)
+                    .filter(DiscoveryNode::isClusterManagerNode)
                     .map(n -> n.getAddress().toString())
                     .distinct()
                     .collect(Collectors.toList());
@@ -1758,7 +1937,7 @@ private void stopNodesAndClient(NodeAndClient nodeAndClient) throws IOException
     }
 
     private synchronized void stopNodesAndClients(Collection<NodeAndClient> nodeAndClients) throws IOException {
-        final Set<String> excludedNodeIds = excludeMasters(nodeAndClients);
+        final Set<String> excludedNodeIds = excludeClusterManagers(nodeAndClients);
 
         for (NodeAndClient nodeAndClient : nodeAndClients) {
             removeDisruptionSchemeFromNode(nodeAndClient);
@@ -1834,11 +2013,11 @@ private void restartNode(NodeAndClient nodeAndClient, RestartCallback callback)
             activeDisruptionScheme.removeFromNode(nodeAndClient.name, this);
         }
 
-        Set<String> excludedNodeIds = excludeMasters(Collections.singleton(nodeAndClient));
+        Set<String> excludedNodeIds = excludeClusterManagers(Collections.singleton(nodeAndClient));
 
         final Settings newSettings = nodeAndClient.closeForRestart(
             callback,
-            autoManageMasterNodes ? getMinMasterNodes(getMasterNodesCount()) : -1
+            autoManageClusterManagerNodes ? getMinClusterManagerNodes(getClusterManagerNodesCount()) : -1
         );
 
         removeExclusions(excludedNodeIds);
@@ -1848,7 +2027,8 @@ private void restartNode(NodeAndClient nodeAndClient, RestartCallback callback)
         publishNode(nodeAndClient);
 
         if (callback.validateClusterForming() || excludedNodeIds.isEmpty() == false) {
-            // we have to validate cluster size to ensure that the restarted node has rejoined the cluster if it was master-eligible;
+            // we have to validate cluster size to ensure that the restarted node has rejoined the cluster if it was
+            // cluster-manager-eligible;
             validateClusterFormed();
         }
     }
@@ -1861,22 +2041,26 @@ private NodeAndClient removeNode(NodeAndClient nodeAndClient) {
         return previous;
     }
 
-    private Set<String> excludeMasters(Collection<NodeAndClient> nodeAndClients) {
+    private Set<String> excludeClusterManagers(Collection<NodeAndClient> nodeAndClients) {
         assert Thread.holdsLock(this);
         final Set<String> excludedNodeNames = new HashSet<>();
-        if (autoManageMasterNodes && nodeAndClients.size() > 0) {
+        if (autoManageClusterManagerNodes && nodeAndClients.size() > 0) {
 
-            final long currentMasters = nodes.values().stream().filter(NodeAndClient::isMasterEligible).count();
-            final long stoppingMasters = nodeAndClients.stream().filter(NodeAndClient::isMasterEligible).count();
+            final long currentClusterManagers = nodes.values().stream().filter(NodeAndClient::isClusterManagerEligible).count();
+            final long stoppingClusterManagers = nodeAndClients.stream().filter(NodeAndClient::isClusterManagerEligible).count();
 
-            assert stoppingMasters <= currentMasters : currentMasters + " < " + stoppingMasters;
-            if (stoppingMasters != currentMasters && stoppingMasters > 0) {
-                // If stopping few enough master-nodes that there's still a majority left, there is no need to withdraw their votes first.
+            assert stoppingClusterManagers <= currentClusterManagers : currentClusterManagers + " < " + stoppingClusterManagers;
+            if (stoppingClusterManagers != currentClusterManagers && stoppingClusterManagers > 0) {
+                // If stopping few enough cluster-manager-nodes that there's still a majority left, there is no need to withdraw their votes
+                // first.
                 // However, we do not yet have a way to be sure there's a majority left, because the voting configuration may not yet have
                 // been updated when the previous nodes shut down, so we must always explicitly withdraw votes.
                 // TODO add cluster health API to check that voting configuration is optimal so this isn't always needed
-                nodeAndClients.stream().filter(NodeAndClient::isMasterEligible).map(NodeAndClient::getName).forEach(excludedNodeNames::add);
-                assert excludedNodeNames.size() == stoppingMasters;
+                nodeAndClients.stream()
+                    .filter(NodeAndClient::isClusterManagerEligible)
+                    .map(NodeAndClient::getName)
+                    .forEach(excludedNodeNames::add);
+                assert excludedNodeNames.size() == stoppingClusterManagers;
 
                 logger.info("adding voting config exclusions {} prior to restart/shutdown", excludedNodeNames);
                 try {
@@ -1911,7 +2095,7 @@ private void removeExclusions(Set<String> excludedNodeIds) {
     public synchronized void fullRestart(RestartCallback callback) throws Exception {
         int numNodesRestarted = 0;
         final Settings[] newNodeSettings = new Settings[nextNodeId.get()];
-        final int minMasterNodes = autoManageMasterNodes ? getMinMasterNodes(getMasterNodesCount()) : -1;
+        final int minClusterManagerNodes = autoManageClusterManagerNodes ? getMinClusterManagerNodes(getClusterManagerNodesCount()) : -1;
         final List<NodeAndClient> toStartAndPublish = new ArrayList<>(); // we want to start nodes in one go
         for (NodeAndClient nodeAndClient : nodes.values()) {
             callback.doAfterNodes(numNodesRestarted++, nodeAndClient.nodeClient());
@@ -1919,7 +2103,7 @@ public synchronized void fullRestart(RestartCallback callback) throws Exception
             if (activeDisruptionScheme != null) {
                 activeDisruptionScheme.removeFromNode(nodeAndClient.name, this);
             }
-            final Settings newSettings = nodeAndClient.closeForRestart(callback, minMasterNodes);
+            final Settings newSettings = nodeAndClient.closeForRestart(callback, minClusterManagerNodes);
             newNodeSettings[nodeAndClient.nodeAndClientId()] = newSettings;
             toStartAndPublish.add(nodeAndClient);
         }
@@ -1942,26 +2126,47 @@ public synchronized void fullRestart(RestartCallback callback) throws Exception
     }
 
     /**
-     * Returns the name of the current master node in the cluster.
+     * Returns the name of the current cluster-manager node in the cluster.
      */
-    public String getMasterName() {
-        return getMasterName(null);
+    public String getClusterManagerName() {
+        return getClusterManagerName(null);
     }
 
     /**
-     * Returns the name of the current master node in the cluster and executes the request via the node specified
+     * Returns the name of the current cluster-manager node in the cluster and executes the request via the node specified
      * in the viaNode parameter. If viaNode isn't specified a random node will be picked to the send the request to.
      */
-    public String getMasterName(@Nullable String viaNode) {
+    public String getClusterManagerName(@Nullable String viaNode) {
         try {
             Client client = viaNode != null ? client(viaNode) : client();
-            return client.admin().cluster().prepareState().get().getState().nodes().getMasterNode().getName();
+            return client.admin().cluster().prepareState().get().getState().nodes().getClusterManagerNode().getName();
         } catch (Exception e) {
             logger.warn("Can't fetch cluster state", e);
-            throw new RuntimeException("Can't get master node " + e.getMessage(), e);
+            throw new RuntimeException("Can't get cluster-manager node " + e.getMessage(), e);
         }
     }
 
+    /**
+     * Returns the name of the current cluster-manager node in the cluster.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerName()}
+     */
+    @Deprecated
+    public String getMasterName() {
+        return getClusterManagerName();
+    }
+
+    /**
+     * Returns the name of the current cluster-manager node in the cluster and executes the request via the node specified
+     * in the viaNode parameter. If viaNode isn't specified a random node will be picked to the send the request to.
+     *
+     * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerName(String)}
+     */
+    @Deprecated
+    public String getMasterName(@Nullable String viaNode) {
+        return getClusterManagerName(viaNode);
+    }
+
     synchronized Set<String> allDataNodesButN(int count) {
         final int numNodes = numDataNodes() - count;
         assert size() >= numNodes;
@@ -1978,6 +2183,10 @@ synchronized Set<String> allDataNodesButN(int count) {
         return set;
     }
 
+    public Set<String> getDataNodeNames() {
+        return allDataNodesButN(0);
+    }
+
     /**
      * Returns a set of nodes that have at least one shard of the given index.
      */
@@ -1998,38 +2207,38 @@ public synchronized Set<String> nodesInclude(String index) {
     }
 
     /**
-     * Performs cluster bootstrap when node with index {@link #bootstrapMasterNodeIndex} is started
-     * with the names of all existing and new master-eligible nodes.
+     * Performs cluster bootstrap when node with index {@link #bootstrapClusterManagerNodeIndex} is started
+     * with the names of all existing and new cluster-manager-eligible nodes.
      * Indexing starts from 0.
-     * If {@link #bootstrapMasterNodeIndex} is -1 (default), this method does nothing.
+     * If {@link #bootstrapClusterManagerNodeIndex} is -1 (default), this method does nothing.
      */
-    private List<Settings> bootstrapMasterNodeWithSpecifiedIndex(List<Settings> allNodesSettings) {
+    private List<Settings> bootstrapClusterManagerNodeWithSpecifiedIndex(List<Settings> allNodesSettings) {
         assert Thread.holdsLock(this);
-        if (bootstrapMasterNodeIndex == -1) { // fast-path
+        if (bootstrapClusterManagerNodeIndex == -1) { // fast-path
             return allNodesSettings;
         }
 
-        int currentNodeId = numMasterNodes() - 1;
+        int currentNodeId = numClusterManagerNodes() - 1;
         List<Settings> newSettings = new ArrayList<>();
 
         for (Settings settings : allNodesSettings) {
-            if (DiscoveryNode.isMasterNode(settings) == false) {
+            if (DiscoveryNode.isClusterManagerNode(settings) == false) {
                 newSettings.add(settings);
             } else {
                 currentNodeId++;
-                if (currentNodeId != bootstrapMasterNodeIndex) {
+                if (currentNodeId != bootstrapClusterManagerNodeIndex) {
                     newSettings.add(settings);
                 } else {
                     List<String> nodeNames = new ArrayList<>();
 
-                    for (Settings nodeSettings : getDataOrMasterNodeInstances(Settings.class)) {
-                        if (DiscoveryNode.isMasterNode(nodeSettings)) {
+                    for (Settings nodeSettings : getDataOrClusterManagerNodeInstances(Settings.class)) {
+                        if (DiscoveryNode.isClusterManagerNode(nodeSettings)) {
                             nodeNames.add(Node.NODE_NAME_SETTING.get(nodeSettings));
                         }
                     }
 
                     for (Settings nodeSettings : allNodesSettings) {
-                        if (DiscoveryNode.isMasterNode(nodeSettings)) {
+                        if (DiscoveryNode.isClusterManagerNode(nodeSettings)) {
                             nodeNames.add(Node.NODE_NAME_SETTING.get(nodeSettings));
                         }
                     }
@@ -2041,7 +2250,7 @@ private List<Settings> bootstrapMasterNodeWithSpecifiedIndex(List<Settings> allN
                             .build()
                     );
 
-                    setBootstrapMasterNodeIndex(-1);
+                    setBootstrapClusterManagerNodeIndex(-1);
                 }
             }
         }
@@ -2088,46 +2297,46 @@ public List<String> startNodes(int numOfNodes, Settings settings) {
      * Starts multiple nodes with the given settings and returns their names
      */
     public synchronized List<String> startNodes(Settings... extraSettings) {
-        final int newMasterCount = Math.toIntExact(Stream.of(extraSettings).filter(DiscoveryNode::isMasterNode).count());
-        final int defaultMinMasterNodes;
-        if (autoManageMasterNodes) {
-            defaultMinMasterNodes = getMinMasterNodes(getMasterNodesCount() + newMasterCount);
+        final int newClusterManagerCount = Math.toIntExact(Stream.of(extraSettings).filter(DiscoveryNode::isClusterManagerNode).count());
+        final int defaultMinClusterManagerNodes;
+        if (autoManageClusterManagerNodes) {
+            defaultMinClusterManagerNodes = getMinClusterManagerNodes(getClusterManagerNodesCount() + newClusterManagerCount);
         } else {
-            defaultMinMasterNodes = -1;
+            defaultMinClusterManagerNodes = -1;
         }
         final List<NodeAndClient> nodes = new ArrayList<>();
-        final int prevMasterCount = getMasterNodesCount();
-        int autoBootstrapMasterNodeIndex = autoManageMasterNodes
-            && prevMasterCount == 0
-            && newMasterCount > 0
+        final int prevClusterManagerCount = getClusterManagerNodesCount();
+        int autoBootstrapClusterManagerNodeIndex = autoManageClusterManagerNodes
+            && prevClusterManagerCount == 0
+            && newClusterManagerCount > 0
             && Arrays.stream(extraSettings)
-                .allMatch(s -> DiscoveryNode.isMasterNode(s) == false || ZEN2_DISCOVERY_TYPE.equals(DISCOVERY_TYPE_SETTING.get(s)))
-                    ? RandomNumbers.randomIntBetween(random, 0, newMasterCount - 1)
+                .allMatch(s -> DiscoveryNode.isClusterManagerNode(s) == false || ZEN2_DISCOVERY_TYPE.equals(DISCOVERY_TYPE_SETTING.get(s)))
+                    ? RandomNumbers.randomIntBetween(random, 0, newClusterManagerCount - 1)
                     : -1;
 
         final int numOfNodes = extraSettings.length;
         final int firstNodeId = nextNodeId.getAndIncrement();
         final List<Settings> settings = new ArrayList<>();
         for (int i = 0; i < numOfNodes; i++) {
-            settings.add(getNodeSettings(firstNodeId + i, random.nextLong(), extraSettings[i], defaultMinMasterNodes));
+            settings.add(getNodeSettings(firstNodeId + i, random.nextLong(), extraSettings[i], defaultMinClusterManagerNodes));
         }
         nextNodeId.set(firstNodeId + numOfNodes);
 
-        final List<String> initialMasterNodes = settings.stream()
-            .filter(DiscoveryNode::isMasterNode)
+        final List<String> initialClusterManagerNodes = settings.stream()
+            .filter(DiscoveryNode::isClusterManagerNode)
             .map(Node.NODE_NAME_SETTING::get)
             .collect(Collectors.toList());
 
-        final List<Settings> updatedSettings = bootstrapMasterNodeWithSpecifiedIndex(settings);
+        final List<Settings> updatedSettings = bootstrapClusterManagerNodeWithSpecifiedIndex(settings);
 
         for (int i = 0; i < numOfNodes; i++) {
             final Settings nodeSettings = updatedSettings.get(i);
             final Builder builder = Settings.builder();
-            if (DiscoveryNode.isMasterNode(nodeSettings)) {
-                if (autoBootstrapMasterNodeIndex == 0) {
-                    builder.putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), initialMasterNodes);
+            if (DiscoveryNode.isClusterManagerNode(nodeSettings)) {
+                if (autoBootstrapClusterManagerNodeIndex == 0) {
+                    builder.putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), initialClusterManagerNodes);
                 }
-                autoBootstrapMasterNodeIndex -= 1;
+                autoBootstrapClusterManagerNodeIndex -= 1;
             }
 
             final NodeAndClient nodeAndClient = buildNode(
@@ -2139,18 +2348,41 @@ public synchronized List<String> startNodes(Settings... extraSettings) {
             nodes.add(nodeAndClient);
         }
         startAndPublishNodesAndClients(nodes);
-        if (autoManageMasterNodes) {
+        if (autoManageClusterManagerNodes) {
             validateClusterFormed();
         }
         return nodes.stream().map(NodeAndClient::getName).collect(Collectors.toList());
     }
 
+    public List<String> startClusterManagerOnlyNodes(int numNodes) {
+        return startClusterManagerOnlyNodes(numNodes, Settings.EMPTY);
+    }
+
+    public List<String> startClusterManagerOnlyNodes(int numNodes, Settings settings) {
+        return startNodes(numNodes, Settings.builder().put(onlyRole(settings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)).build());
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #startClusterManagerOnlyNodes(int)} */
+    @Deprecated
     public List<String> startMasterOnlyNodes(int numNodes) {
-        return startMasterOnlyNodes(numNodes, Settings.EMPTY);
+        return startClusterManagerOnlyNodes(numNodes);
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #startClusterManagerOnlyNodes(int, Settings)} */
+    @Deprecated
     public List<String> startMasterOnlyNodes(int numNodes, Settings settings) {
-        return startNodes(numNodes, Settings.builder().put(onlyRole(settings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE)).build());
+        return startClusterManagerOnlyNodes(numNodes, settings);
+    }
+
+    public List<String> startDataAndSearchNodes(int numNodes) {
+        return startDataAndSearchNodes(numNodes, Settings.EMPTY);
+    }
+
+    public List<String> startDataAndSearchNodes(int numNodes, Settings settings) {
+        Set<DiscoveryNodeRole> searchAndDataRoles = new HashSet<>();
+        searchAndDataRoles.add(DiscoveryNodeRole.DATA_ROLE);
+        searchAndDataRoles.add(DiscoveryNodeRole.SEARCH_ROLE);
+        return startNodes(numNodes, Settings.builder().put(onlyRoles(settings, searchAndDataRoles)).build());
     }
 
     public List<String> startDataOnlyNodes(int numNodes) {
@@ -2161,22 +2393,42 @@ public List<String> startDataOnlyNodes(int numNodes, Settings settings) {
         return startNodes(numNodes, Settings.builder().put(onlyRole(settings, DiscoveryNodeRole.DATA_ROLE)).build());
     }
 
-    /** calculates a min master nodes value based on the given number of master nodes */
-    private static int getMinMasterNodes(int eligibleMasterNodes) {
-        return eligibleMasterNodes / 2 + 1;
+    public List<String> startSearchOnlyNodes(int numNodes) {
+        return startSearchOnlyNodes(numNodes, Settings.EMPTY);
+    }
+
+    public List<String> startSearchOnlyNodes(int numNodes, Settings settings) {
+        return startNodes(numNodes, Settings.builder().put(onlyRole(settings, DiscoveryNodeRole.SEARCH_ROLE)).build());
+    }
+
+    /** calculates a min cluster-manager nodes value based on the given number of cluster-manager nodes */
+    private static int getMinClusterManagerNodes(int eligibleClusterManagerNodes) {
+        return eligibleClusterManagerNodes / 2 + 1;
+    }
+
+    private int getClusterManagerNodesCount() {
+        return (int) nodes.values().stream().filter(n -> DiscoveryNode.isClusterManagerNode(n.node().settings())).count();
     }
 
-    private int getMasterNodesCount() {
-        return (int) nodes.values().stream().filter(n -> DiscoveryNode.isMasterNode(n.node().settings())).count();
+    public String startClusterManagerOnlyNode() {
+        return startClusterManagerOnlyNode(Settings.EMPTY);
     }
 
+    public String startClusterManagerOnlyNode(Settings settings) {
+        Settings settings1 = Settings.builder().put(settings).put(NodeRoles.clusterManagerOnlyNode(settings)).build();
+        return startNode(settings1);
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #startClusterManagerOnlyNode()} */
+    @Deprecated
     public String startMasterOnlyNode() {
-        return startMasterOnlyNode(Settings.EMPTY);
+        return startClusterManagerOnlyNode();
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #startClusterManagerOnlyNode(Settings)} */
+    @Deprecated
     public String startMasterOnlyNode(Settings settings) {
-        Settings settings1 = Settings.builder().put(settings).put(masterOnlyNode(settings)).build();
-        return startNode(settings1);
+        return startClusterManagerOnlyNode(settings);
     }
 
     public String startDataOnlyNode() {
@@ -2205,13 +2457,27 @@ public int numDataNodes() {
         return dataNodeAndClients().size();
     }
 
+    public int numSearchNodes() {
+        return searchNodeAndClients().size();
+    }
+
+    public int numSearchAndDataNodes() {
+        return searchDataNodeAndClients().size();
+    }
+
     @Override
-    public int numDataAndMasterNodes() {
-        return filterNodes(nodes, DATA_NODE_PREDICATE.or(MASTER_NODE_PREDICATE)).size();
+    public int numDataAndClusterManagerNodes() {
+        return filterNodes(nodes, DATA_NODE_PREDICATE.or(CLUSTER_MANAGER_NODE_PREDICATE)).size();
+    }
+
+    public int numClusterManagerNodes() {
+        return filterNodes(nodes, NodeAndClient::isClusterManagerEligible).size();
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #numClusterManagerNodes()} */
+    @Deprecated
     public int numMasterNodes() {
-        return filterNodes(nodes, NodeAndClient::isMasterEligible).size();
+        return numClusterManagerNodes();
     }
 
     public void setDisruptionScheme(ServiceDisruptionScheme scheme) {
@@ -2258,6 +2524,14 @@ private Collection<NodeAndClient> dataNodeAndClients() {
         return filterNodes(nodes, DATA_NODE_PREDICATE);
     }
 
+    private Collection<NodeAndClient> searchNodeAndClients() {
+        return filterNodes(nodes, SEARCH_NODE_PREDICATE);
+    }
+
+    private Collection<NodeAndClient> searchDataNodeAndClients() {
+        return filterNodes(nodes, SEARCH_AND_DATA_NODE_PREDICATE);
+    }
+
     private static Collection<NodeAndClient> filterNodes(
         Map<String, InternalTestCluster.NodeAndClient> map,
         Predicate<NodeAndClient> predicate
@@ -2438,6 +2712,12 @@ public void ensureEstimatedStats() {
                     false,
                     false,
                     false,
+                    false,
+                    false,
+                    false,
+                    false,
+                    false,
+                    false,
                     false
                 );
                 assertThat(
diff --git a/test/framework/src/main/java/org/opensearch/test/MockHttpTransport.java b/test/framework/src/main/java/org/opensearch/test/MockHttpTransport.java
index 7661b21c7cc0e..841cf62620f0d 100644
--- a/test/framework/src/main/java/org/opensearch/test/MockHttpTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/MockHttpTransport.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.test;
 
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.http.HttpInfo;
 import org.opensearch.http.HttpServerTransport;
 import org.opensearch.http.HttpStats;
diff --git a/test/framework/src/main/java/org/opensearch/test/MockIndexEventListener.java b/test/framework/src/main/java/org/opensearch/test/MockIndexEventListener.java
index ecdae6a0e8b64..e8f22a409bf09 100644
--- a/test/framework/src/main/java/org/opensearch/test/MockIndexEventListener.java
+++ b/test/framework/src/main/java/org/opensearch/test/MockIndexEventListener.java
@@ -37,14 +37,14 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.index.Index;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
 import org.opensearch.plugins.Plugin;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/NodeRoles.java b/test/framework/src/main/java/org/opensearch/test/NodeRoles.java
index 64fd6b22e9805..4285ac76fc4d4 100644
--- a/test/framework/src/main/java/org/opensearch/test/NodeRoles.java
+++ b/test/framework/src/main/java/org/opensearch/test/NodeRoles.java
@@ -168,28 +168,64 @@ public static Settings nonIngestNode(final Settings settings) {
         return removeRoles(settings, Collections.singleton(DiscoveryNodeRole.INGEST_ROLE));
     }
 
+    public static Settings clusterManagerNode() {
+        return clusterManagerNode(Settings.EMPTY);
+    }
+
+    public static Settings clusterManagerNode(final Settings settings) {
+        return addRoles(settings, Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
+    }
+
+    public static Settings clusterManagerOnlyNode() {
+        return clusterManagerOnlyNode(Settings.EMPTY);
+    }
+
+    public static Settings clusterManagerOnlyNode(final Settings settings) {
+        return onlyRole(settings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
+    }
+
+    public static Settings nonClusterManagerNode() {
+        return nonClusterManagerNode(Settings.EMPTY);
+    }
+
+    public static Settings nonClusterManagerNode(final Settings settings) {
+        return removeRoles(settings, Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNode()} */
+    @Deprecated
     public static Settings masterNode() {
-        return masterNode(Settings.EMPTY);
+        return clusterManagerNode();
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerNode(Settings)} */
+    @Deprecated
     public static Settings masterNode(final Settings settings) {
-        return addRoles(settings, Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
+        return clusterManagerNode(settings);
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerOnlyNode()} */
+    @Deprecated
     public static Settings masterOnlyNode() {
-        return masterOnlyNode(Settings.EMPTY);
+        return clusterManagerOnlyNode();
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerOnlyNode(Settings)} */
+    @Deprecated
     public static Settings masterOnlyNode(final Settings settings) {
-        return onlyRole(settings, DiscoveryNodeRole.CLUSTER_MANAGER_ROLE);
+        return clusterManagerOnlyNode(settings);
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #nonClusterManagerNode()} */
+    @Deprecated
     public static Settings nonMasterNode() {
-        return nonMasterNode(Settings.EMPTY);
+        return nonClusterManagerNode();
     }
 
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #nonClusterManagerNode(Settings)} */
+    @Deprecated
     public static Settings nonMasterNode(final Settings settings) {
-        return removeRoles(settings, Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE));
+        return nonClusterManagerNode(settings);
     }
 
     public static Settings remoteClusterClientNode() {
@@ -208,4 +244,20 @@ public static Settings nonRemoteClusterClientNode(final Settings settings) {
         return removeRoles(settings, Collections.singleton(DiscoveryNodeRole.REMOTE_CLUSTER_CLIENT_ROLE));
     }
 
+    public static Settings searchNode() {
+        return searchNode(Settings.EMPTY);
+    }
+
+    public static Settings searchNode(final Settings settings) {
+        return addRoles(settings, Collections.singleton(DiscoveryNodeRole.SEARCH_ROLE));
+    }
+
+    public static Settings nonSearchNode() {
+        return nonSearchNode(Settings.EMPTY);
+    }
+
+    public static Settings nonSearchNode(final Settings settings) {
+        return removeRoles(settings, Collections.singleton(DiscoveryNodeRole.SEARCH_ROLE));
+    }
+
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java b/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
index 1c09fb2ff8c04..1fcb7fa6a4bf1 100644
--- a/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
@@ -36,19 +36,21 @@
 import com.carrotsearch.randomizedtesting.annotations.TestGroup;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.http.HttpHost;
+import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.tests.util.LuceneTestCase;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionListener;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.DocWriteResponse;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.cluster.node.hotthreads.NodeHotThreads;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
 import org.opensearch.action.admin.cluster.tasks.PendingClusterTasksResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
@@ -68,9 +70,7 @@
 import org.opensearch.action.index.IndexResponse;
 import org.opensearch.action.search.ClearScrollResponse;
 import org.opensearch.action.search.SearchResponse;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.IndicesOptions;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.client.AdminClient;
 import org.opensearch.client.Client;
 import org.opensearch.client.ClusterAdminClient;
@@ -92,46 +92,55 @@
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.UnassignedInfo;
+import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
+import org.opensearch.cluster.routing.allocation.decider.AwarenessAllocationDecider;
 import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.regex.Regex;
+import org.opensearch.common.settings.FeatureFlagSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
-import org.opensearch.common.unit.ByteSizeUnit;
-import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.util.concurrent.OpenSearchRejectedExecutionException;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.smile.SmileXContent;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.common.unit.ByteSizeUnit;
+import org.opensearch.core.common.unit.ByteSizeValue;
+import org.opensearch.core.concurrency.OpenSearchRejectedExecutionException;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.env.Environment;
 import org.opensearch.env.TestEnvironment;
 import org.opensearch.http.HttpInfo;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.MergePolicyConfig;
 import org.opensearch.index.MergeSchedulerConfig;
 import org.opensearch.index.MockEngineFactoryPlugin;
+import org.opensearch.index.TieredMergePolicyProvider;
 import org.opensearch.index.codec.CodecService;
 import org.opensearch.index.engine.Segment;
+import org.opensearch.index.mapper.CompletionFieldMapper;
 import org.opensearch.index.mapper.MockFieldFilterPlugin;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
@@ -143,17 +152,20 @@
 import org.opensearch.node.NodeMocksPlugin;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestCancellableNodeClient;
 import org.opensearch.script.MockScriptService;
 import org.opensearch.script.ScriptMetadata;
 import org.opensearch.search.MockSearchService;
+import org.opensearch.search.SearchBootstrapSettings;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchService;
+import org.opensearch.telemetry.TelemetrySettings;
 import org.opensearch.test.client.RandomizingClient;
 import org.opensearch.test.disruption.NetworkDisruption;
 import org.opensearch.test.disruption.ServiceDisruptionScheme;
 import org.opensearch.test.store.MockFSIndexStore;
+import org.opensearch.test.telemetry.MockTelemetryPlugin;
+import org.opensearch.test.telemetry.tracing.StrictCheckSpanProcessor;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
@@ -166,6 +178,7 @@
 import org.junit.BeforeClass;
 
 import java.io.IOException;
+import java.lang.Runtime.Version;
 import java.lang.annotation.Annotation;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
@@ -200,7 +213,7 @@
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.common.unit.TimeValue.timeValueMillis;
-import static org.opensearch.common.util.CollectionUtils.eagerPartition;
+import static org.opensearch.core.common.util.CollectionUtils.eagerPartition;
 import static org.opensearch.discovery.DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING;
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
 import static org.opensearch.index.IndexSettings.INDEX_SOFT_DELETES_RETENTION_LEASE_PERIOD_SETTING;
@@ -364,6 +377,17 @@ public abstract class OpenSearchIntegTestCase extends OpenSearchTestCase {
     private static OpenSearchIntegTestCase INSTANCE = null; // see @SuiteScope
     private static Long SUITE_SEED = null;
 
+    /**
+     * The lucene_default {@link Codec} is not added to the list as it internally maps to Asserting {@link Codec}.
+     * The override to fetch the {@link CompletionFieldMapper.CompletionFieldType} postings format is not available for this codec.
+     */
+    public static final List<String> CODECS = List.of(
+        CodecService.DEFAULT_CODEC,
+        CodecService.LZ4,
+        CodecService.BEST_COMPRESSION_CODEC,
+        CodecService.ZLIB
+    );
+
     @BeforeClass
     public static void beforeClass() throws Exception {
         SUITE_SEED = randomLong();
@@ -411,7 +435,7 @@ private void printTestMessage(String message) {
      * Creates a randomized index template. This template is used to pass in randomized settings on a
      * per index basis. Allows to enable/disable the randomization for number of shards and replicas
      */
-    private void randomIndexTemplate() {
+    protected void randomIndexTemplate() {
 
         // TODO move settings for random directory etc here into the index based randomized settings.
         if (cluster().size() > 0) {
@@ -427,7 +451,7 @@ private void randomIndexTemplate() {
             // otherwise, use it, it has assertions and so on that can find bugs.
             SuppressCodecs annotation = getClass().getAnnotation(SuppressCodecs.class);
             if (annotation != null && annotation.value().length == 1 && "*".equals(annotation.value()[0])) {
-                randomSettingsBuilder.put("index.codec", randomFrom(CodecService.DEFAULT_CODEC, CodecService.BEST_COMPRESSION_CODEC));
+                randomSettingsBuilder.put("index.codec", randomFrom(CODECS));
             } else {
                 randomSettingsBuilder.put("index.codec", CodecService.LUCENE_DEFAULT_CODEC);
             }
@@ -484,7 +508,7 @@ protected Settings.Builder setRandomIndexSettings(Random random, Settings.Builde
     private static Settings.Builder setRandomIndexMergeSettings(Random random, Settings.Builder builder) {
         if (random.nextBoolean()) {
             builder.put(
-                MergePolicyConfig.INDEX_COMPOUND_FORMAT_SETTING.getKey(),
+                TieredMergePolicyProvider.INDEX_COMPOUND_FORMAT_SETTING.getKey(),
                 (random.nextBoolean() ? random.nextDouble() : random.nextBoolean()).toString()
             );
         }
@@ -577,44 +601,34 @@ private static void clearClusters() throws Exception {
     }
 
     private void afterInternal(boolean afterClass) throws Exception {
-        boolean success = false;
+        final Scope currentClusterScope = getCurrentClusterScope();
+        if (isInternalCluster()) {
+            internalCluster().clearDisruptionScheme();
+        }
         try {
-            final Scope currentClusterScope = getCurrentClusterScope();
-            if (isInternalCluster()) {
-                internalCluster().clearDisruptionScheme();
-            }
-            try {
-                if (cluster() != null) {
-                    if (currentClusterScope != Scope.TEST) {
-                        Metadata metadata = client().admin().cluster().prepareState().execute().actionGet().getState().getMetadata();
+            if (cluster() != null) {
+                if (currentClusterScope != Scope.TEST) {
+                    Metadata metadata = client().admin().cluster().prepareState().execute().actionGet().getState().getMetadata();
 
-                        final Set<String> persistentKeys = new HashSet<>(metadata.persistentSettings().keySet());
-                        assertThat("test leaves persistent cluster metadata behind", persistentKeys, empty());
+                    final Set<String> persistentKeys = new HashSet<>(metadata.persistentSettings().keySet());
+                    assertThat("test leaves persistent cluster metadata behind", persistentKeys, empty());
 
-                        final Set<String> transientKeys = new HashSet<>(metadata.transientSettings().keySet());
-                        assertThat("test leaves transient cluster metadata behind", transientKeys, empty());
-                    }
-                    ensureClusterSizeConsistency();
-                    ensureClusterStateConsistency();
-                    ensureClusterStateCanBeReadByNodeTool();
-                    beforeIndexDeletion();
-                    cluster().wipe(excludeTemplates()); // wipe after to make sure we fail in the test that didn't ack the delete
-                    if (afterClass || currentClusterScope == Scope.TEST) {
-                        cluster().close();
-                    }
-                    cluster().assertAfterTest();
+                    final Set<String> transientKeys = new HashSet<>(metadata.transientSettings().keySet());
+                    assertThat("test leaves transient cluster metadata behind", transientKeys, empty());
                 }
-            } finally {
-                if (currentClusterScope == Scope.TEST) {
-                    clearClusters(); // it is ok to leave persistent / transient cluster state behind if scope is TEST
+                ensureClusterSizeConsistency();
+                ensureClusterStateConsistency();
+                ensureClusterStateCanBeReadByNodeTool();
+                beforeIndexDeletion();
+                cluster().wipe(excludeTemplates()); // wipe after to make sure we fail in the test that didn't ack the delete
+                if (afterClass || currentClusterScope == Scope.TEST) {
+                    cluster().close();
                 }
+                cluster().assertAfterTest();
             }
-            success = true;
         } finally {
-            if (!success) {
-                // if we failed here that means that something broke horribly so we should clear all clusters
-                // TODO: just let the exception happen, WTF is all this horseshit
-                // afterTestRule.forceFailure();
+            if (currentClusterScope == Scope.TEST) {
+                clearClusters(); // it is ok to leave persistent / transient cluster state behind if scope is TEST
             }
         }
     }
@@ -707,17 +721,19 @@ public void setDisruptionScheme(ServiceDisruptionScheme scheme) {
     }
 
     /**
-     * Creates a disruption that isolates the current master node from all other nodes in the cluster.
+     * Creates a disruption that isolates the current cluster-manager node from all other nodes in the cluster.
      *
      * @param disruptionType type of disruption to create
      * @return disruption
      */
-    protected static NetworkDisruption isolateMasterDisruption(NetworkDisruption.NetworkLinkDisruptionType disruptionType) {
-        final String masterNode = internalCluster().getMasterName();
+    protected static NetworkDisruption isolateClusterManagerDisruption(NetworkDisruption.NetworkLinkDisruptionType disruptionType) {
+        final String clusterManagerNode = internalCluster().getClusterManagerName();
         return new NetworkDisruption(
             new NetworkDisruption.TwoPartitions(
-                Collections.singleton(masterNode),
-                Arrays.stream(internalCluster().getNodeNames()).filter(name -> name.equals(masterNode) == false).collect(Collectors.toSet())
+                Collections.singleton(clusterManagerNode),
+                Arrays.stream(internalCluster().getNodeNames())
+                    .filter(name -> name.equals(clusterManagerNode) == false)
+                    .collect(Collectors.toSet())
             ),
             disruptionType
         );
@@ -761,9 +777,26 @@ public Settings indexSettings() {
                 ).getStringRep()
             );
         }
+
         return builder.build();
     }
 
+    /**
+     * Setting all feature flag settings at base IT, which can be overridden later by individual
+     * IT classes.
+     *
+     * @return Feature flag settings.
+     */
+    protected Settings featureFlagSettings() {
+        Settings.Builder featureSettings = Settings.builder();
+        for (Setting builtInFlag : FeatureFlagSettings.BUILT_IN_FEATURE_FLAGS) {
+            featureSettings.put(builtInFlag.getKey(), builtInFlag.getDefaultRaw(Settings.EMPTY));
+        }
+        // Enabling Telemetry setting by default
+        featureSettings.put(FeatureFlags.TELEMETRY_SETTING.getKey(), true);
+        return featureSettings.build();
+    }
+
     /**
      * Creates one or more indices and asserts that the indices are acknowledged. If one of the indices
      * already exists this method will fail and wipe all the indices created so far.
@@ -925,6 +958,13 @@ public ClusterHealthStatus ensureYellow(String... indices) {
         return ensureColor(ClusterHealthStatus.YELLOW, TimeValue.timeValueSeconds(30), false, indices);
     }
 
+    /**
+     * Ensures the cluster has a red state via the cluster health API.
+     */
+    public ClusterHealthStatus ensureRed(String... indices) {
+        return ensureColor(ClusterHealthStatus.RED, TimeValue.timeValueSeconds(30), false, indices);
+    }
+
     /**
      * Ensures the cluster has a yellow state via the cluster health API and ensures the that cluster has no initializing shards
      * for the given indices
@@ -949,12 +989,13 @@ private ClusterHealthStatus ensureColor(
             .waitForNoRelocatingShards(true)
             .waitForNoInitializingShards(waitForNoInitializingShards)
             // We currently often use ensureGreen or ensureYellow to check whether the cluster is back in a good state after shutting down
-            // a node. If the node that is stopped is the master node, another node will become master and publish a cluster state where it
-            // is master but where the node that was stopped hasn't been removed yet from the cluster state. It will only subsequently
-            // publish a second state where the old master is removed. If the ensureGreen/ensureYellow is timed just right, it will get to
-            // execute before the second cluster state update removes the old master and the condition ensureGreen / ensureYellow will
-            // trivially hold if it held before the node was shut down. The following "waitForNodes" condition ensures that the node has
-            // been removed by the master so that the health check applies to the set of nodes we expect to be part of the cluster.
+            // a node. If the node that is stopped is the cluster-manager node, another node will become cluster-manager and publish a
+            // cluster state where it is cluster-manager but where the node that was stopped hasn't been removed yet from the cluster state.
+            // It will only subsequently publish a second state where the old cluster-manager is removed.
+            // If the ensureGreen/ensureYellow is timed just right, it will get to execute before the second cluster state update removes
+            // the old cluster-manager and the condition ensureGreen / ensureYellow will trivially hold if it held before the node was
+            // shut down. The following "waitForNodes" condition ensures that the node has been removed by the cluster-manager
+            // so that the health check applies to the set of nodes we expect to be part of the cluster.
             .waitForNodes(Integer.toString(cluster().size()));
 
         ClusterHealthResponse actionGet = client().admin().cluster().health(healthRequest).actionGet();
@@ -1066,6 +1107,23 @@ public void waitForDocs(final long numDocs, final BackgroundIndexer indexer) thr
         }, maxWaitTimeMs, TimeUnit.MILLISECONDS);
     }
 
+    /**
+     * Waits until at least a give number of document is indexed by indexer
+     *
+     * @param numDocs number of documents to wait for
+     * @param indexer a {@link BackgroundIndexer}. It will be first checked for documents indexed.
+     *                This saves on unneeded searches.
+     */
+    public void waitForIndexed(final long numDocs, final BackgroundIndexer indexer) throws Exception {
+        // indexing threads can wait for up to ~1m before retrying when they first try to index into a shard which is not STARTED.
+        final long maxWaitTimeMs = Math.max(90 * 1000, 200 * numDocs);
+
+        assertBusy(() -> {
+            long lastKnownCount = indexer.totalIndexedDocs();
+            assertThat(lastKnownCount, greaterThanOrEqualTo(numDocs));
+        }, maxWaitTimeMs, TimeUnit.MILLISECONDS);
+    }
+
     /**
      * Prints the current cluster state as debug logging.
      */
@@ -1085,19 +1143,19 @@ protected void ensureClusterSizeConsistency() {
     }
 
     /**
-     * Verifies that all nodes that have the same version of the cluster state as master have same cluster state
+     * Verifies that all nodes that have the same version of the cluster state as cluster-manager have same cluster state
      */
     protected void ensureClusterStateConsistency() throws IOException {
         if (cluster() != null && cluster().size() > 0) {
             final NamedWriteableRegistry namedWriteableRegistry = cluster().getNamedWriteableRegistry();
-            final Client masterClient = client();
-            ClusterState masterClusterState = masterClient.admin().cluster().prepareState().all().get().getState();
-            byte[] masterClusterStateBytes = ClusterState.Builder.toBytes(masterClusterState);
+            final Client clusterManagerClient = client();
+            ClusterState clusterManagerClusterState = clusterManagerClient.admin().cluster().prepareState().all().get().getState();
+            byte[] masterClusterStateBytes = ClusterState.Builder.toBytes(clusterManagerClusterState);
             // remove local node reference
-            masterClusterState = ClusterState.Builder.fromBytes(masterClusterStateBytes, null, namedWriteableRegistry);
-            Map<String, Object> masterStateMap = convertToMap(masterClusterState);
-            int masterClusterStateSize = masterClusterState.toString().length();
-            String masterId = masterClusterState.nodes().getMasterNodeId();
+            clusterManagerClusterState = ClusterState.Builder.fromBytes(masterClusterStateBytes, null, namedWriteableRegistry);
+            Map<String, Object> clusterManagerStateMap = convertToMap(clusterManagerClusterState);
+            int clusterManagerClusterStateSize = clusterManagerClusterState.toString().length();
+            String clusterManagerId = clusterManagerClusterState.nodes().getClusterManagerNodeId();
             for (Client client : cluster().getClients()) {
                 ClusterState localClusterState = client.admin().cluster().prepareState().all().setLocal(true).get().getState();
                 byte[] localClusterStateBytes = ClusterState.Builder.toBytes(localClusterState);
@@ -1105,27 +1163,32 @@ protected void ensureClusterStateConsistency() throws IOException {
                 localClusterState = ClusterState.Builder.fromBytes(localClusterStateBytes, null, namedWriteableRegistry);
                 final Map<String, Object> localStateMap = convertToMap(localClusterState);
                 final int localClusterStateSize = localClusterState.toString().length();
-                // Check that the non-master node has the same version of the cluster state as the master and
-                // that the master node matches the master (otherwise there is no requirement for the cluster state to match)
-                if (masterClusterState.version() == localClusterState.version()
-                    && masterId.equals(localClusterState.nodes().getMasterNodeId())) {
+                // Check that the non-cluster-manager node has the same version of the cluster state as the cluster-manager and
+                // that the cluster-manager node matches the cluster-manager (otherwise there is no requirement for the cluster state to
+                // match)
+                if (clusterManagerClusterState.version() == localClusterState.version()
+                    && clusterManagerId.equals(localClusterState.nodes().getClusterManagerNodeId())) {
                     try {
-                        assertEquals("cluster state UUID does not match", masterClusterState.stateUUID(), localClusterState.stateUUID());
+                        assertEquals(
+                            "cluster state UUID does not match",
+                            clusterManagerClusterState.stateUUID(),
+                            localClusterState.stateUUID()
+                        );
                         // We cannot compare serialization bytes since serialization order of maps is not guaranteed
                         // We also cannot compare byte array size because CompressedXContent's DeflateCompressor uses
                         // a synced flush that can affect the size of the compressed byte array
                         // (see: DeflateCompressedXContentTests#testDifferentCompressedRepresentation for an example)
                         // instead we compare the string length of cluster state - they should be the same
-                        assertEquals("cluster state size does not match", masterClusterStateSize, localClusterStateSize);
+                        assertEquals("cluster state size does not match", clusterManagerClusterStateSize, localClusterStateSize);
                         // Compare JSON serialization
                         assertNull(
                             "cluster state JSON serialization does not match",
-                            differenceBetweenMapsIgnoringArrayOrder(masterStateMap, localStateMap)
+                            differenceBetweenMapsIgnoringArrayOrder(clusterManagerStateMap, localStateMap)
                         );
                     } catch (final AssertionError error) {
                         logger.error(
-                            "Cluster state from master:\n{}\nLocal cluster state:\n{}",
-                            masterClusterState.toString(),
+                            "Cluster state from cluster-manager:\n{}\nLocal cluster state:\n{}",
+                            clusterManagerClusterState.toString(),
                             localClusterState.toString()
                         );
                         throw error;
@@ -1138,8 +1201,8 @@ protected void ensureClusterStateConsistency() throws IOException {
 
     protected void ensureClusterStateCanBeReadByNodeTool() throws IOException {
         if (cluster() != null && cluster().size() > 0) {
-            final Client masterClient = client();
-            Metadata metadata = masterClient.admin().cluster().prepareState().all().get().getState().metadata();
+            final Client clusterManagerClient = client();
+            Metadata metadata = clusterManagerClient.admin().cluster().prepareState().all().get().getState().metadata();
             final Map<String, String> serializationParams = new HashMap<>(2);
             serializationParams.put("binary", "true");
             serializationParams.put(Metadata.CONTEXT_MODE_PARAM, Metadata.CONTEXT_MODE_GATEWAY);
@@ -1252,13 +1315,13 @@ protected void ensureClusterStateCanBeReadByNodeTool() throws IOException {
      */
     private ClusterState removePluginCustoms(final ClusterState clusterState) {
         final ClusterState.Builder builder = ClusterState.builder(clusterState);
-        clusterState.customs().keysIt().forEachRemaining(key -> {
+        clusterState.customs().keySet().iterator().forEachRemaining(key -> {
             if (SAFE_CUSTOMS.contains(key) == false) {
                 builder.removeCustom(key);
             }
         });
         final Metadata.Builder mdBuilder = Metadata.builder(clusterState.metadata());
-        clusterState.metadata().customs().keysIt().forEachRemaining(key -> {
+        clusterState.metadata().customs().keySet().iterator().forEachRemaining(key -> {
             if (SAFE_METADATA_CUSTOMS.contains(key) == false) {
                 mdBuilder.removeCustom(key);
             }
@@ -1320,7 +1383,7 @@ protected void ensureStableCluster(int nodeCount, TimeValue timeValue, boolean l
     /**
      * Ensures that all nodes in the cluster are connected to each other.
      *
-     * Some network disruptions may leave nodes that are not the master disconnected from each other.
+     * Some network disruptions may leave nodes that are not the cluster-manager disconnected from each other.
      * {@link org.opensearch.cluster.NodeConnectionsService} will eventually reconnect but it's
      * handy to be able to ensure this happens faster
      */
@@ -1381,7 +1444,7 @@ protected final IndexResponse index(String index, String type, String id, Object
      */
     @Deprecated
     protected final IndexResponse index(String index, String type, String id, String source) {
-        return client().prepareIndex(index).setId(id).setSource(source, XContentType.JSON).execute().actionGet();
+        return client().prepareIndex(index).setId(id).setSource(source, MediaTypeRegistry.JSON).execute().actionGet();
     }
 
     /**
@@ -1432,6 +1495,18 @@ protected ForceMergeResponse forceMerge() {
         return actionGet;
     }
 
+    protected ForceMergeResponse forceMerge(int maxNumSegments) {
+        waitForRelocation();
+        ForceMergeResponse actionGet = client().admin()
+            .indices()
+            .prepareForceMerge()
+            .setMaxNumSegments(maxNumSegments)
+            .execute()
+            .actionGet();
+        assertNoFailures(actionGet);
+        return actionGet;
+    }
+
     /**
      * Returns <code>true</code> iff the given index exists otherwise <code>false</code>
      */
@@ -1553,7 +1628,7 @@ public void indexRandom(boolean forceRefresh, boolean dummyDocuments, boolean ma
                 String index = RandomPicks.randomFrom(random, indices);
                 bogusIds.add(Arrays.asList(index, id));
                 // We configure a routing key in case the mapping requires it
-                builders.add(client().prepareIndex().setIndex(index).setId(id).setSource("{}", XContentType.JSON).setRouting(id));
+                builders.add(client().prepareIndex().setIndex(index).setId(id).setSource("{}", MediaTypeRegistry.JSON).setRouting(id));
             }
         }
         Collections.shuffle(builders, random());
@@ -1738,9 +1813,9 @@ public enum Scope {
         int maxNumDataNodes() default -1;
 
         /**
-         * Indicates whether the cluster can have dedicated master nodes. If {@code false} means data nodes will serve as master nodes
-         * and there will be no dedicated master (and data) nodes. Default is {@code false} which means
-         * dedicated master nodes will be randomly used.
+         * Indicates whether the cluster can have dedicated cluster-manager nodes. If {@code false} means data nodes will serve as cluster-manager nodes
+         * and there will be no dedicated cluster-manager (and data) nodes. Default is {@code false} which means
+         * dedicated cluster-manager nodes will be randomly used.
          */
         boolean supportsDedicatedMasters() default true;
 
@@ -1829,12 +1904,12 @@ private static Scope getCurrentClusterScope(Class<?> clazz) {
         return annotation == null ? Scope.SUITE : annotation.scope();
     }
 
-    private boolean getSupportsDedicatedMasters() {
+    private boolean getSupportsDedicatedClusterManagers() {
         ClusterScope annotation = getAnnotation(this.getClass(), ClusterScope.class);
         return annotation == null ? true : annotation.supportsDedicatedMasters();
     }
 
-    private boolean getAutoManageMasterNodes() {
+    private boolean getAutoManageClusterManagerNodes() {
         ClusterScope annotation = getAnnotation(this.getClass(), ClusterScope.class);
         return annotation == null ? true : annotation.autoManageMasterNodes();
     }
@@ -1871,6 +1946,7 @@ private int getNumClientNodes() {
      * In other words subclasses must ensure this method is idempotent.
      */
     protected Settings nodeSettings(int nodeOrdinal) {
+        final Settings featureFlagSettings = featureFlagSettings();
         Settings.Builder builder = Settings.builder()
             // Default the watermarks to absurdly low to prevent the tests
             // from failing on nodes without enough disk space
@@ -1887,12 +1963,23 @@ protected Settings nodeSettings(int nodeOrdinal) {
             .put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), randomBoolean())
             .putList(DISCOVERY_SEED_HOSTS_SETTING.getKey()) // empty list disables a port scan for other nodes
             .putList(DISCOVERY_SEED_PROVIDERS_SETTING.getKey(), "file");
+        // add all the featureFlagSettings set by the test
+        builder.put(featureFlagSettings);
         if (rarely()) {
             // Sometimes adjust the minimum search thread pool size, causing
             // QueueResizingOpenSearchThreadPoolExecutor to be used instead of a regular
             // fixed thread pool
             builder.put("thread_pool.search.min_queue_size", 100);
         }
+        if (FeatureFlags.CONCURRENT_SEGMENT_SEARCH_SETTING.get(featureFlagSettings)) {
+            // By default, for tests we will put the target slice count of 2. This will increase the probability of having multiple slices
+            // when tests are run with concurrent segment search enabled
+            builder.put(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY, 2);
+        }
+        // Enable tracer only when Telemetry Setting is enabled
+        if (featureFlagSettings().getAsBoolean(FeatureFlags.TELEMETRY_SETTING.getKey(), false)) {
+            builder.put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true);
+        }
         return builder.build();
     }
 
@@ -1959,7 +2046,7 @@ protected TestCluster buildTestCluster(Scope scope, long seed) throws IOExceptio
                 throw new OpenSearchException("Scope not supported: " + scope);
         }
 
-        boolean supportsDedicatedMasters = getSupportsDedicatedMasters();
+        boolean supportsDedicatedClusterManagers = getSupportsDedicatedClusterManagers();
         int numDataNodes = getNumDataNodes();
         int minNumDataNodes;
         int maxNumDataNodes;
@@ -1983,8 +2070,8 @@ protected TestCluster buildTestCluster(Scope scope, long seed) throws IOExceptio
         return new InternalTestCluster(
             seed,
             createTempDir(),
-            supportsDedicatedMasters,
-            getAutoManageMasterNodes(),
+            supportsDedicatedClusterManagers,
+            getAutoManageClusterManagerNodes(),
             minNumDataNodes,
             maxNumDataNodes,
             InternalTestCluster.clusterName(scope.name(), seed) + "-cluster",
@@ -2048,6 +2135,15 @@ protected boolean addMockGeoShapeFieldMapper() {
         return true;
     }
 
+    /**
+     * Returns {@code true} if this test cluster should have tracing enabled with MockTelemetryPlugin
+     * Disabling this for now as the existing way of strict check do not support multiple nodes internal cluster.
+     * @return boolean.
+     */
+    protected boolean addMockTelemetryPlugin() {
+        return true;
+    }
+
     /**
      * Returns a function that allows to wrap / filter all clients that are exposed by the test cluster. This is useful
      * for debugging or request / response pre and post processing. It also allows to intercept all calls done by the test
@@ -2092,6 +2188,9 @@ protected Collection<Class<? extends Plugin>> getMockPlugins() {
         if (addMockGeoShapeFieldMapper()) {
             mocks.add(TestGeoShapeFieldMapperPlugin.class);
         }
+        if (addMockTelemetryPlugin()) {
+            mocks.add(MockTelemetryPlugin.class);
+        }
         return Collections.unmodifiableList(mocks);
     }
 
@@ -2227,7 +2326,7 @@ public final void cleanUpCluster() throws Exception {
         // need to check that there are no more in-flight search contexts before
         // we remove indices
         if (isInternalCluster()) {
-            internalCluster().setBootstrapMasterNodeIndex(-1);
+            internalCluster().setBootstrapClusterManagerNodeIndex(-1);
         }
         super.ensureAllSearchContextsReleased();
         if (runTestScopeLifecycle()) {
@@ -2247,6 +2346,7 @@ public static void afterClass() throws Exception {
                 INSTANCE.afterInternal(true);
                 checkStaticState(true);
             }
+            StrictCheckSpanProcessor.validateTracingStateOnShutdown();
         } finally {
             SUITE_SEED = null;
             currentCluster = null;
@@ -2264,8 +2364,12 @@ private static void initializeSuiteScope() throws Exception {
          */
         assert INSTANCE == null;
         if (isSuiteScopedTest(targetClass)) {
-            // note we need to do this this way to make sure this is reproducible
-            INSTANCE = (OpenSearchIntegTestCase) targetClass.getConstructor().newInstance();
+            // note we need to do this way to make sure this is reproducible
+            if (isSuiteScopedTestParameterized(targetClass)) {
+                INSTANCE = (OpenSearchIntegTestCase) targetClass.getConstructor(Settings.class).newInstance(Settings.EMPTY);
+            } else {
+                INSTANCE = (OpenSearchIntegTestCase) targetClass.getConstructor().newInstance();
+            }
             boolean success = false;
             try {
                 INSTANCE.printTestMessage("setup");
@@ -2360,6 +2464,16 @@ private static boolean isSuiteScopedTest(Class<?> clazz) {
         return clazz.getAnnotation(SuiteScopeTestCase.class) != null;
     }
 
+    /*
+    * For tests defined with, SuiteScopeTestCase return true if the
+    * class has a constructor that takes a single Settings parameter
+    * */
+    private static boolean isSuiteScopedTestParameterized(Class<?> clazz) {
+        return Arrays.stream(clazz.getConstructors())
+            .filter(x -> x.getParameterTypes().length == 1)
+            .anyMatch(x -> x.getParameterTypes()[0].equals(Settings.class));
+    }
+
     /**
      * If a test is annotated with {@link SuiteScopeTestCase}
      * the checks and modifications that are applied to the used test cluster are only done after all tests
@@ -2403,7 +2517,69 @@ protected boolean willSufferDebian8MemoryProblem() {
         final boolean anyDebian8Nodes = response.getNodes()
             .stream()
             .anyMatch(ni -> ni.getInfo(OsInfo.class).getPrettyName().equals("Debian GNU/Linux 8 (jessie)"));
-        boolean java15Plus = JavaVersion.current().compareTo(JavaVersion.parse("15")) >= 0;
+        boolean java15Plus = Runtime.version().compareTo(Version.parse("15")) >= 0;
         return anyDebian8Nodes && java15Plus == false;
     }
+
+    public void manageReplicaBalanceSetting(boolean apply) {
+        Settings settings;
+        if (apply) {
+            settings = Settings.builder()
+                .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+                .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values", "a, b")
+                .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+                .build();
+        } else {
+            settings = Settings.builder()
+                .putNull(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey())
+                .putNull(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values")
+                .putNull(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey())
+                .build();
+        }
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        updateSettingsRequest.persistentSettings(settings);
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+    }
+
+    public void manageReplicaSettingForDefaultReplica(boolean apply) {
+        Settings settings;
+        if (apply) {
+            settings = Settings.builder()
+                .put(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey(), "zone")
+                .put(
+                    AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values",
+                    "a, b, c"
+                )
+                .put(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey(), true)
+                .put(Metadata.DEFAULT_REPLICA_COUNT_SETTING.getKey(), 2)
+                .build();
+        } else {
+            settings = Settings.builder()
+                .putNull(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey())
+                .putNull(AwarenessAllocationDecider.CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING.getKey() + "zone.values")
+                .putNull(AwarenessReplicaBalance.CLUSTER_ROUTING_ALLOCATION_AWARENESS_BALANCE_SETTING.getKey())
+                .putNull(Metadata.DEFAULT_REPLICA_COUNT_SETTING.getKey())
+                .build();
+        }
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        updateSettingsRequest.persistentSettings(settings);
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+    }
+
+    protected String primaryNodeName(String indexName) {
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        String nodeId = clusterState.getRoutingTable().index(indexName).shard(0).primaryShard().currentNodeId();
+        return clusterState.getRoutingNodes().node(nodeId).node().getName();
+    }
+
+    protected String replicaNodeName(String indexName) {
+        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
+        String nodeId = clusterState.getRoutingTable().index(indexName).shard(0).replicaShards().get(0).currentNodeId();
+        return clusterState.getRoutingNodes().node(nodeId).node().getName();
+    }
+
+    protected ClusterState getClusterState() {
+        return client(internalCluster().getClusterManagerName()).admin().cluster().prepareState().get().getState();
+    }
+
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/OpenSearchSingleNodeTestCase.java b/test/framework/src/main/java/org/opensearch/test/OpenSearchSingleNodeTestCase.java
index e3f6e6019546b..8977f081b5512 100644
--- a/test/framework/src/main/java/org/opensearch/test/OpenSearchSingleNodeTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/OpenSearchSingleNodeTestCase.java
@@ -32,6 +32,7 @@
 package org.opensearch.test;
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
+
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexRequestBuilder;
@@ -45,17 +46,20 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.allocation.DiskThresholdSettings;
 import org.opensearch.common.Priority;
-import org.opensearch.common.Strings;
+import org.opensearch.common.settings.FeatureFlagSettings;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.index.Index;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.indices.IndicesService;
@@ -65,7 +69,11 @@
 import org.opensearch.node.NodeValidationException;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.script.MockScriptService;
+import org.opensearch.search.SearchBootstrapSettings;
 import org.opensearch.search.internal.SearchContext;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.test.telemetry.MockTelemetryPlugin;
+import org.opensearch.test.telemetry.tracing.StrictCheckSpanProcessor;
 import org.opensearch.transport.TransportSettings;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -97,7 +105,7 @@ protected void startNode(long seed) throws Exception {
         assert NODE == null;
         NODE = RandomizedContext.current().runWithPrivateRandomness(seed, this::newNode);
         // we must wait for the node to actually be up and running. otherwise the node might have started,
-        // elected itself master but might not yet have removed the
+        // elected itself cluster-manager but might not yet have removed the
         // SERVICE_UNAVAILABLE/1/state not recovered / initialized block
         ClusterHealthResponse clusterHealthResponse = client().admin().cluster().prepareHealth().setWaitForGreenStatus().get();
         assertFalse(clusterHealthResponse.isTimedOut());
@@ -183,6 +191,7 @@ public static void setUpClass() throws Exception {
     @AfterClass
     public static void tearDownClass() throws Exception {
         stopNode();
+        StrictCheckSpanProcessor.validateTracingStateOnShutdown();
     }
 
     /**
@@ -220,7 +229,7 @@ private Node newNode() {
         final Path tempDir = createTempDir();
         final String nodeName = nodeSettings().get(Node.NODE_NAME_SETTING.getKey(), "node_s_0");
 
-        Settings settings = Settings.builder()
+        Settings.Builder settingsBuilder = Settings.builder()
             .put(ClusterName.CLUSTER_NAME_SETTING.getKey(), InternalTestCluster.clusterName("single-node-cluster", random().nextLong()))
             .put(Environment.PATH_HOME_SETTING.getKey(), tempDir)
             .put(Environment.PATH_REPO_SETTING.getKey(), tempDir.resolve("repo"))
@@ -242,8 +251,16 @@ private Node newNode() {
             .put(HierarchyCircuitBreakerService.USE_REAL_MEMORY_USAGE_SETTING.getKey(), false)
             .putList(DISCOVERY_SEED_HOSTS_SETTING.getKey()) // empty list disables a port scan for other nodes
             .putList(INITIAL_CLUSTER_MANAGER_NODES_SETTING.getKey(), nodeName)
+            .put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true)
             .put(nodeSettings()) // allow test cases to provide their own settings or override these
-            .build();
+            .put(featureFlagSettings());
+
+        if (Boolean.parseBoolean(settingsBuilder.get(FeatureFlags.CONCURRENT_SEGMENT_SEARCH))
+            && (settingsBuilder.get(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY) == null)) {
+            // By default, for tests we will put the target slice count of 2 if not explicitly set. This will increase the probability of
+            // having multiple slices when tests are run with concurrent segment search enabled
+            settingsBuilder.put(SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_KEY, 2);
+        }
 
         Collection<Class<? extends Plugin>> plugins = getPlugins();
         if (plugins.contains(getTestTransportPlugin()) == false) {
@@ -254,7 +271,8 @@ private Node newNode() {
             plugins.add(MockHttpTransport.TestPlugin.class);
         }
         plugins.add(MockScriptService.TestPlugin.class);
-        Node node = new MockNode(settings, plugins, forbidPrivateIndexSettings());
+        plugins.add(MockTelemetryPlugin.class);
+        Node node = new MockNode(settingsBuilder.build(), plugins, forbidPrivateIndexSettings());
         try {
             node.start();
         } catch (NodeValidationException e) {
@@ -408,4 +426,19 @@ protected boolean forbidPrivateIndexSettings() {
         return true;
     }
 
+    /**
+     * Setting all feature flag settings at base IT, which can be overridden later by individual
+     * IT classes.
+     *
+     * @return Feature flag settings.
+     */
+    protected Settings featureFlagSettings() {
+        Settings.Builder featureSettings = Settings.builder();
+        for (Setting builtInFlag : FeatureFlagSettings.BUILT_IN_FEATURE_FLAGS) {
+            featureSettings.put(builtInFlag.getKey(), builtInFlag.getDefaultRaw(Settings.EMPTY));
+        }
+        featureSettings.put(FeatureFlags.TELEMETRY_SETTING.getKey(), true);
+        return featureSettings.build();
+    }
+
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java b/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
index 96698036fca55..8490ee4fc39bc 100644
--- a/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
@@ -42,6 +42,7 @@
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
 import com.carrotsearch.randomizedtesting.rules.TestRuleAdapter;
+
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -62,52 +63,54 @@
 import org.apache.lucene.tests.util.TimeUnits;
 import org.opensearch.Version;
 import org.opensearch.bootstrap.BootstrapForTesting;
-import org.opensearch.bootstrap.JavaVersion;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.ClusterModule;
+import org.opensearch.cluster.coordination.PersistedStateRegistry;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.CheckedRunnable;
+import org.opensearch.common.Numbers;
 import org.opensearch.common.SuppressForbidden;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.io.PathUtilsForTesting;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteable;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.Writeable;
 import org.opensearch.common.joda.JodaDeprecationPatterns;
 import org.opensearch.common.logging.DeprecatedMessage;
 import org.opensearch.common.logging.HeaderWarning;
 import org.opensearch.common.logging.HeaderWarningAppender;
-import org.opensearch.common.logging.LogConfigurator;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.time.DateUtils;
 import org.opensearch.common.time.FormatNames;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.util.set.Sets;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentParser.Token;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteable;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.Writeable;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.index.Index;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentHelper;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.env.TestEnvironment;
-import org.opensearch.index.Index;
+import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.AnalysisRegistry;
 import org.opensearch.index.analysis.AnalyzerScope;
@@ -116,6 +119,7 @@
 import org.opensearch.index.analysis.NamedAnalyzer;
 import org.opensearch.index.analysis.TokenFilterFactory;
 import org.opensearch.index.analysis.TokenizerFactory;
+import org.opensearch.index.store.remote.filecache.FileCache;
 import org.opensearch.indices.analysis.AnalysisModule;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.plugins.AnalysisPlugin;
@@ -127,6 +131,7 @@
 import org.opensearch.test.junit.listeners.LoggingListener;
 import org.opensearch.test.junit.listeners.ReproduceInfoPrinter;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
 import org.opensearch.transport.nio.MockNioTransportPlugin;
 import org.joda.time.DateTimeZone;
 import org.junit.After;
@@ -171,7 +176,7 @@
 import java.util.stream.Stream;
 
 import static java.util.Collections.emptyMap;
-import static org.opensearch.common.util.CollectionUtils.arrayAsArrayList;
+import static org.opensearch.core.common.util.CollectionUtils.arrayAsArrayList;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItem;
@@ -218,6 +223,12 @@ public static void resetPortCounter() {
         portGenerator.set(0);
     }
 
+    @Override
+    public void tearDown() throws Exception {
+        FeatureFlagSetter.clear();
+        super.tearDown();
+    }
+
     // Allows distinguishing between parallel test processes
     public static final String TEST_WORKER_VM_ID;
 
@@ -230,7 +241,6 @@ public static void resetPortCounter() {
     static {
         TEST_WORKER_VM_ID = System.getProperty(TEST_WORKER_SYS_PROPERTY, DEFAULT_TEST_WORKER_ID);
         setTestSysProps();
-        LogConfigurator.loadLog4jPlugins();
 
         String leakLoggerName = "io.netty.util.ResourceLeakDetector";
         Logger leakLogger = LogManager.getLogger(leakLoggerName);
@@ -256,6 +266,7 @@ public void append(LogEvent event) {
         }));
 
         BootstrapForTesting.ensureInitialized();
+        TransportService.ensureClassloaded(); // ensure server streamables are registered
 
         // filter out joda timezones that are deprecated for the java time migration
         List<String> jodaTZIds = DateTimeZone.getAvailableIDs()
@@ -355,7 +366,7 @@ public static void setContentType() throws Exception {
     @AfterClass
     public static void restoreContentType() {
         Requests.CONTENT_TYPE = XContentType.SMILE;
-        Requests.INDEX_CONTENT_TYPE = XContentType.JSON;
+        Requests.INDEX_CONTENT_TYPE = MediaTypeRegistry.JSON;
     }
 
     @BeforeClass
@@ -803,6 +814,22 @@ public static long randomLong() {
         return random().nextLong();
     }
 
+    /**
+     * Returns a random BigInteger uniformly distributed over the range 0 to (2^64 - 1) inclusive
+     * Currently BigIntegers are only used for unsigned_long field type, where the max value is 2^64 - 1.
+     * Modify this random generator if a wider range for BigIntegers is necessary.
+     * @return a random bigInteger in the range [0 ; 2^64 - 1]
+     */
+    public static BigInteger randomUnsignedLong() {
+        BigInteger value = randomBigInteger().abs();
+
+        while (value.compareTo(Numbers.MAX_UNSIGNED_LONG_VALUE) == 1) {
+            value = value.subtract(Numbers.MAX_UNSIGNED_LONG_VALUE);
+        }
+
+        return value;
+    }
+
     /**
      * Returns a random BigInteger uniformly distributed over the range 0 to (2^64 - 1) inclusive
      * Currently BigIntegers are only used for unsigned_long field type, where the max value is 2^64 - 1.
@@ -883,6 +910,15 @@ public static String randomRealisticUnicodeOfCodepointLength(int codePoints) {
         return RandomizedTest.randomRealisticUnicodeOfCodepointLength(codePoints);
     }
 
+    public static String replaceUnicodeControlCharacters(String uniCodeStr, String toReplaceWith) {
+        // replace control characters (https://stackoverflow.com/questions/3438854/replace-unicode-control-characters/)
+        return uniCodeStr.replaceAll("\\p{Cc}", toReplaceWith);
+    }
+
+    public static String replaceUnicodeControlCharacters(String uniCodeStr) {
+        return replaceUnicodeControlCharacters(uniCodeStr, " ");
+    }
+
     /**
      * @param maxArraySize The maximum number of elements in the random array
      * @param stringSize The length of each String in the array
@@ -967,17 +1003,7 @@ public static TimeZone randomTimeZone() {
      * generate a random TimeZone from the ones available in java.time
      */
     public static ZoneId randomZone() {
-        // work around a JDK bug, where java 8 cannot parse the timezone GMT0 back into a temporal accessor
-        // see https://bugs.openjdk.java.net/browse/JDK-8138664
-        if (JavaVersion.current().getVersion().get(0) == 8) {
-            ZoneId timeZone;
-            do {
-                timeZone = ZoneId.of(randomJodaAndJavaSupportedTimezone(JAVA_ZONE_IDS));
-            } while (timeZone.equals(ZoneId.of("GMT0")));
-            return timeZone;
-        } else {
-            return ZoneId.of(randomJodaAndJavaSupportedTimezone(JAVA_ZONE_IDS));
-        }
+        return ZoneId.of(randomJodaAndJavaSupportedTimezone(JAVA_ZONE_IDS));
     }
 
     /**
@@ -1176,6 +1202,14 @@ public static Settings.Builder settings(Version version) {
         return builder;
     }
 
+    public static Settings.Builder remoteIndexSettings(Version version) {
+        Settings.Builder builder = Settings.builder()
+            .put(FileCache.DATA_TO_FILE_CACHE_SIZE_RATIO_SETTING.getKey(), 5)
+            .put(IndexMetadata.SETTING_VERSION_CREATED, version)
+            .put(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.REMOTE_SNAPSHOT.getSettingsKey());
+        return builder;
+    }
+
     /**
      * Returns size random values
      */
@@ -1248,7 +1282,10 @@ public GeohashGenerator() {
      * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
      * {@link XContentType}. Wraps the output into a new anonymous object according to the value returned
      * by the {@link ToXContent#isFragment()} method returns. Shuffles the keys to make sure that parsing never relies on keys ordering.
+     *
+     * @deprecated use {@link #toShuffledXContent(ToXContent, MediaType, ToXContent.Params, boolean, String...)} instead
      */
+    @Deprecated
     protected final BytesReference toShuffledXContent(
         ToXContent toXContent,
         XContentType xContentType,
@@ -1264,6 +1301,26 @@ protected final BytesReference toShuffledXContent(
         }
     }
 
+    /**
+     * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
+     * {@link XContentType}. Wraps the output into a new anonymous object according to the value returned
+     * by the {@link ToXContent#isFragment()} method returns. Shuffles the keys to make sure that parsing never relies on keys ordering.
+     */
+    protected final BytesReference toShuffledXContent(
+        ToXContent toXContent,
+        MediaType mediaType,
+        ToXContent.Params params,
+        boolean humanReadable,
+        String... exceptFieldNames
+    ) throws IOException {
+        BytesReference bytes = org.opensearch.core.xcontent.XContentHelper.toXContent(toXContent, mediaType, params, humanReadable);
+        try (XContentParser parser = createParser(mediaType.xContent(), bytes)) {
+            try (XContentBuilder builder = shuffleXContent(parser, rarely(), exceptFieldNames)) {
+                return BytesReference.bytes(builder);
+            }
+        }
+    }
+
     /**
      * Randomly shuffles the fields inside objects in the {@link XContentBuilder} passed in.
      * Recursively goes through inner objects and also shuffles them. Exceptions for this
@@ -1284,7 +1341,7 @@ protected final XContentBuilder shuffleXContent(XContentBuilder builder, String.
      */
     public static XContentBuilder shuffleXContent(XContentParser parser, boolean prettyPrint, String... exceptFieldNames)
         throws IOException {
-        XContentBuilder xContentBuilder = XContentFactory.contentBuilder(parser.contentType());
+        XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(parser.contentType());
         if (prettyPrint) {
             xContentBuilder.prettyPrint();
         }
@@ -1487,6 +1544,13 @@ protected NamedWriteableRegistry writableRegistry() {
         return new NamedWriteableRegistry(ClusterModule.getNamedWriteables());
     }
 
+    /**
+     * The {@link PersistedStateRegistry} to use for this test. Subclasses should override and use liberally.
+     */
+    protected PersistedStateRegistry persistedStateRegistry() {
+        return new PersistedStateRegistry();
+    }
+
     /**
      * Create a "mock" script for use either with {@link MockScriptEngine} or anywhere where you need a script but don't really care about
      * its contents.
diff --git a/test/framework/src/main/java/org/opensearch/test/ParameterizedOpenSearchIntegTestCase.java b/test/framework/src/main/java/org/opensearch/test/ParameterizedOpenSearchIntegTestCase.java
new file mode 100644
index 0000000000000..636064d8e4f9d
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/ParameterizedOpenSearchIntegTestCase.java
@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsModule;
+import org.junit.After;
+import org.junit.Before;
+
+/**
+ * Base class for running the tests with parameterization of the dynamic settings
+ * For any class that wants to use parameterization, use @ParametersFactory to generate
+ * different params only for dynamic settings. Refer SearchCancellationIT for an example.
+ * Note: this doesn't work for the parameterization of feature flag/static settings.
+ */
+public abstract class ParameterizedOpenSearchIntegTestCase extends OpenSearchIntegTestCase {
+
+    private final Settings dynamicSettings;
+
+    public ParameterizedOpenSearchIntegTestCase(Settings dynamicSettings) {
+        this.dynamicSettings = dynamicSettings;
+    }
+
+    @Before
+    public void beforeTests() {
+        SettingsModule settingsModule = new SettingsModule(dynamicSettings);
+        for (String key : dynamicSettings.keySet()) {
+            assertTrue(
+                settingsModule.getClusterSettings().isDynamicSetting(key) || settingsModule.getIndexScopedSettings().isDynamicSetting(key)
+            );
+        }
+        client().admin().cluster().prepareUpdateSettings().setPersistentSettings(dynamicSettings).get();
+    }
+
+    @After
+    public void afterTests() {
+        final Settings.Builder settingsToUnset = Settings.builder();
+        dynamicSettings.keySet().forEach(settingsToUnset::putNull);
+        client().admin().cluster().prepareUpdateSettings().setPersistentSettings(settingsToUnset).get();
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/PosixPermissionsResetter.java b/test/framework/src/main/java/org/opensearch/test/PosixPermissionsResetter.java
index df03bfab57e57..344e61de7d5bd 100644
--- a/test/framework/src/main/java/org/opensearch/test/PosixPermissionsResetter.java
+++ b/test/framework/src/main/java/org/opensearch/test/PosixPermissionsResetter.java
@@ -31,8 +31,6 @@
 
 package org.opensearch.test;
 
-import java.util.EnumSet;
-import java.util.Set;
 import org.junit.Assert;
 
 import java.io.IOException;
@@ -40,6 +38,8 @@
 import java.nio.file.Path;
 import java.nio.file.attribute.PosixFileAttributeView;
 import java.nio.file.attribute.PosixFilePermission;
+import java.util.EnumSet;
+import java.util.Set;
 
 /** Stores the posix attributes for a path and resets them on close. */
 public class PosixPermissionsResetter implements AutoCloseable {
diff --git a/test/framework/src/main/java/org/opensearch/test/RandomObjects.java b/test/framework/src/main/java/org/opensearch/test/RandomObjects.java
index 55da731e8311f..a11fb3425d7af 100644
--- a/test/framework/src/main/java/org/opensearch/test/RandomObjects.java
+++ b/test/framework/src/main/java/org/opensearch/test/RandomObjects.java
@@ -43,19 +43,20 @@
 import org.opensearch.action.support.replication.ReplicationResponse.ShardInfo;
 import org.opensearch.action.support.replication.ReplicationResponse.ShardInfo.Failure;
 import org.opensearch.cluster.block.ClusterBlockException;
-import org.opensearch.cluster.coordination.NoMasterBlockService;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.cluster.coordination.NoClusterManagerBlockService;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.shard.IndexShardRecoveringException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardNotFoundException;
-import org.opensearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -66,12 +67,12 @@
 import java.util.Map;
 import java.util.Random;
 
-import static com.carrotsearch.randomizedtesting.generators.RandomNumbers.randomIntBetween;
-import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomAsciiLettersOfLength;
-import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomUnicodeOfLengthBetween;
 import static java.util.Collections.singleton;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_UUID_NA_VALUE;
 import static org.opensearch.test.OpenSearchTestCase.randomFrom;
+import static com.carrotsearch.randomizedtesting.generators.RandomNumbers.randomIntBetween;
+import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomAsciiLettersOfLength;
+import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomUnicodeOfLengthBetween;
 
 public final class RandomObjects {
 
@@ -81,20 +82,23 @@ private RandomObjects() {
 
     /**
      * Returns a tuple containing random stored field values and their corresponding expected values once printed out
-     * via {@link org.opensearch.common.xcontent.ToXContent#toXContent(XContentBuilder, ToXContent.Params)} and parsed back via
-     * {@link org.opensearch.common.xcontent.XContentParser#objectText()}.
+     * via {@link ToXContent#toXContent(XContentBuilder, ToXContent.Params)} and parsed back via
+     * {@link XContentParser#objectText()}.
      * Generates values based on what can get printed out. Stored fields values are retrieved from lucene and converted via
      * {@link org.opensearch.index.mapper.MappedFieldType#valueForDisplay(Object)} to either strings, numbers or booleans.
      *
      * @param random Random generator
-     * @param xContentType the content type, used to determine what the expected values are for float numbers.
+     * @param mediaType the content type, used to determine what the expected values are for float numbers.
      */
-    public static Tuple<List<Object>, List<Object>> randomStoredFieldValues(Random random, XContentType xContentType) {
+    public static Tuple<List<Object>, List<Object>> randomStoredFieldValues(Random random, MediaType mediaType) {
+        if (mediaType instanceof XContentType == false) {
+            throw new IllegalArgumentException("Unable to parse media type [" + mediaType.getClass().getName() + "]");
+        }
         int numValues = randomIntBetween(random, 1, 5);
         List<Object> originalValues = randomStoredFieldValues(random, numValues);
         List<Object> expectedParsedValues = new ArrayList<>(numValues);
         for (Object originalValue : originalValues) {
-            expectedParsedValues.add(getExpectedParsedValue(xContentType, originalValue));
+            expectedParsedValues.add(getExpectedParsedValue(mediaType, originalValue));
         }
         return Tuple.tuple(originalValues, expectedParsedValues);
     }
@@ -145,20 +149,20 @@ private static List<Object> randomStoredFieldValues(Random random, int numValues
 
     /**
      * Converts the provided field value to its corresponding expected value once printed out
-     * via {@link org.opensearch.common.xcontent.ToXContent#toXContent(XContentBuilder, ToXContent.Params)} and parsed back via
-     * {@link org.opensearch.common.xcontent.XContentParser#objectText()}.
+     * via {@link ToXContent#toXContent(XContentBuilder, ToXContent.Params)} and parsed back via
+     * {@link XContentParser#objectText()}.
      * Generates values based on what can get printed out. Stored fields values are retrieved from lucene and converted via
      * {@link org.opensearch.index.mapper.MappedFieldType#valueForDisplay(Object)} to either strings, numbers or booleans.
      */
-    public static Object getExpectedParsedValue(XContentType xContentType, Object value) {
+    public static Object getExpectedParsedValue(MediaType mediaType, Object value) {
         if (value instanceof BytesArray) {
-            if (xContentType == XContentType.JSON) {
+            if (mediaType == MediaTypeRegistry.JSON) {
                 // JSON writes base64 format
                 return Base64.getEncoder().encodeToString(((BytesArray) value).toBytesRef().bytes);
             }
         }
         if (value instanceof Float) {
-            if (xContentType == XContentType.CBOR || xContentType == XContentType.SMILE) {
+            if (mediaType == XContentType.CBOR || mediaType == XContentType.SMILE) {
                 // with binary content types we pass back the object as is
                 return value;
             }
@@ -190,8 +194,8 @@ public static BytesReference randomSource(Random random) {
      *
      * @param random Random generator
      */
-    public static BytesReference randomSource(Random random, XContentType xContentType) {
-        return randomSource(random, xContentType, 1);
+    public static BytesReference randomSource(Random random, final MediaType mediaType) {
+        return randomSource(random, mediaType, 1);
     }
 
     /**
@@ -200,8 +204,8 @@ public static BytesReference randomSource(Random random, XContentType xContentTy
      *
      * @param random Random generator
      */
-    public static BytesReference randomSource(Random random, XContentType xContentType, int minNumFields) {
-        try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType)) {
+    public static BytesReference randomSource(Random random, final MediaType mediaType, int minNumFields) {
+        try (XContentBuilder builder = mediaType.contentBuilder()) {
             builder.startObject();
             addFields(random, builder, minNumFields, 0);
             builder.endObject();
@@ -331,9 +335,10 @@ private static Tuple<Failure, Failure> randomShardInfoFailure(Random random) {
         int type = randomIntBetween(random, 0, 3);
         switch (type) {
             case 0:
-                actualException = new ClusterBlockException(singleton(NoMasterBlockService.NO_MASTER_BLOCK_WRITES));
+                actualException = new ClusterBlockException(singleton(NoClusterManagerBlockService.NO_CLUSTER_MANAGER_BLOCK_WRITES));
                 expectedException = new OpenSearchException(
-                    "OpenSearch exception [type=cluster_block_exception, " + "reason=blocked by: [SERVICE_UNAVAILABLE/2/no master];]"
+                    "OpenSearch exception [type=cluster_block_exception, "
+                        + "reason=blocked by: [SERVICE_UNAVAILABLE/2/no cluster-manager];]"
                 );
                 break;
             case 1:
diff --git a/test/framework/src/main/java/org/opensearch/test/RemoteStoreTestUtils.java b/test/framework/src/main/java/org/opensearch/test/RemoteStoreTestUtils.java
new file mode 100644
index 0000000000000..2e0b846d801e2
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/RemoteStoreTestUtils.java
@@ -0,0 +1,130 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test;
+
+import org.apache.lucene.codecs.CodecUtil;
+import org.apache.lucene.index.SegmentInfos;
+import org.apache.lucene.store.ByteBuffersDataOutput;
+import org.apache.lucene.store.ByteBuffersIndexOutput;
+import org.apache.lucene.store.OutputStreamIndexOutput;
+import org.apache.lucene.util.Version;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.index.store.remote.metadata.RemoteSegmentMetadata;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.test.OpenSearchTestCase.randomIntBetween;
+
+/**
+ * Utilities for remote store related operations used across one or more tests.
+ */
+public final class RemoteStoreTestUtils {
+
+    private RemoteStoreTestUtils() {
+
+    }
+
+    /**
+     * Prepares metadata file bytes with header and footer
+     *
+     * @param segmentFilesMap: actual metadata content
+     * @return ByteArrayIndexInput: metadata file bytes with header and footer
+     * @throws IOException IOException
+     */
+    public static InputStream createMetadataFileBytes(
+        Map<String, String> segmentFilesMap,
+        ReplicationCheckpoint replicationCheckpoint,
+        SegmentInfos segmentInfos
+    ) throws IOException {
+        ByteBuffersDataOutput byteBuffersIndexOutput = new ByteBuffersDataOutput();
+        segmentInfos.write(new ByteBuffersIndexOutput(byteBuffersIndexOutput, "", ""));
+        byte[] byteArray = byteBuffersIndexOutput.toArrayCopy();
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput("segment metadata", "metadata output stream", output, 4096);
+        CodecUtil.writeHeader(indexOutput, RemoteSegmentMetadata.METADATA_CODEC, RemoteSegmentMetadata.CURRENT_VERSION);
+        indexOutput.writeMapOfStrings(segmentFilesMap);
+        RemoteSegmentMetadata.writeCheckpointToIndexOutput(replicationCheckpoint, indexOutput);
+        indexOutput.writeLong(byteArray.length);
+        indexOutput.writeBytes(byteArray, byteArray.length);
+        CodecUtil.writeFooter(indexOutput);
+        indexOutput.close();
+        return new ByteArrayInputStream(BytesReference.toBytes(output.bytes()));
+    }
+
+    public static Map<String, String> getDummyMetadata(String prefix, int commitGeneration) {
+        Map<String, String> metadata = new HashMap<>();
+
+        metadata.put(
+            prefix + ".cfe",
+            prefix
+                + ".cfe::"
+                + prefix
+                + ".cfe__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(512000, 1024000)
+                + "::"
+                + Version.MIN_SUPPORTED_MAJOR
+        );
+        metadata.put(
+            prefix + ".cfs",
+            prefix
+                + ".cfs::"
+                + prefix
+                + ".cfs__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(512000, 1024000)
+                + "::"
+                + Version.MIN_SUPPORTED_MAJOR
+        );
+        metadata.put(
+            prefix + ".si",
+            prefix
+                + ".si::"
+                + prefix
+                + ".si__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(512000, 1024000)
+                + "::"
+                + Version.LATEST.major
+        );
+        metadata.put(
+            "segments_" + commitGeneration,
+            "segments_"
+                + commitGeneration
+                + "::segments_"
+                + commitGeneration
+                + "__"
+                + UUIDs.base64UUID()
+                + "::"
+                + randomIntBetween(1000, 5000)
+                + "::"
+                + randomIntBetween(1024, 5120)
+                + "::"
+                + Version.LATEST.major
+        );
+        return metadata;
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/StreamsUtils.java b/test/framework/src/main/java/org/opensearch/test/StreamsUtils.java
index 6579815deeb48..25884b88c5811 100644
--- a/test/framework/src/main/java/org/opensearch/test/StreamsUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/StreamsUtils.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.test;
 
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.core.internal.io.Streams;
+import org.opensearch.common.util.io.Streams;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/test/TestCluster.java b/test/framework/src/main/java/org/opensearch/test/TestCluster.java
index 2bc0ffd941502..a9d9abf69ee41 100644
--- a/test/framework/src/main/java/org/opensearch/test/TestCluster.java
+++ b/test/framework/src/main/java/org/opensearch/test/TestCluster.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.test;
 
-import com.carrotsearch.hppc.ObjectArrayList;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
@@ -44,15 +42,19 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.indices.IndexTemplateMissingException;
 import org.opensearch.repositories.RepositoryMissingException;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.test.hamcrest.OpenSearchAssertions;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Random;
 import java.util.Set;
 
@@ -125,9 +127,21 @@ public void assertAfterTest() throws Exception {
     public abstract int numDataNodes();
 
     /**
-     * Returns the number of data and master eligible nodes in the cluster.
+     * Returns the number of data and cluster-manager eligible nodes in the cluster.
      */
-    public abstract int numDataAndMasterNodes();
+    // TODO: Add abstract keyword after removing the deprecated numDataAndMasterNodes()
+    public int numDataAndClusterManagerNodes() {
+        return numDataAndMasterNodes();
+    }
+
+    /**
+     * Returns the number of data and cluster-manager eligible nodes in the cluster.
+     * @deprecated As of 2.1, because supporting inclusive language, replaced by {@link #numDataAndClusterManagerNodes()}
+     */
+    @Deprecated
+    public int numDataAndMasterNodes() {
+        throw new UnsupportedOperationException("Must be overridden");
+    }
 
     /**
      * Returns the http addresses of the nodes within the cluster.
@@ -177,12 +191,14 @@ public void wipeIndices(String... indices) {
                 // which is the case in the CloseIndexDisableCloseAllTests
                 if ("_all".equals(indices[0])) {
                     ClusterStateResponse clusterStateResponse = client().admin().cluster().prepareState().execute().actionGet();
-                    ObjectArrayList<String> concreteIndices = new ObjectArrayList<>();
+                    List<String> concreteIndices = new ArrayList<>();
                     for (IndexMetadata indexMetadata : clusterStateResponse.getState().metadata()) {
                         concreteIndices.add(indexMetadata.getIndex().getName());
                     }
                     if (!concreteIndices.isEmpty()) {
-                        OpenSearchAssertions.assertAcked(client().admin().indices().prepareDelete(concreteIndices.toArray(String.class)));
+                        OpenSearchAssertions.assertAcked(
+                            client().admin().indices().prepareDelete(concreteIndices.toArray(new String[concreteIndices.size()]))
+                        );
                     }
                 }
             }
@@ -239,7 +255,18 @@ public void wipeRepositories(String... repositories) {
             }
             for (String repository : repositories) {
                 try {
-                    client().admin().cluster().prepareDeleteRepository(repository).execute().actionGet();
+                    List<RepositoryMetadata> repositoryMetadata = client().admin()
+                        .cluster()
+                        .prepareGetRepositories(repository)
+                        .execute()
+                        .actionGet()
+                        .repositories();
+                    if (repositoryMetadata.isEmpty() == false
+                        && BlobStoreRepository.SYSTEM_REPOSITORY_SETTING.get(repositoryMetadata.get(0).settings()) == true) {
+                        client().admin().cluster().prepareCleanupRepository(repository).execute().actionGet();
+                    } else {
+                        client().admin().cluster().prepareDeleteRepository(repository).execute().actionGet();
+                    }
                 } catch (RepositoryMissingException ex) {
                     // ignore
                 }
diff --git a/test/framework/src/main/java/org/opensearch/test/TestCustomMetadata.java b/test/framework/src/main/java/org/opensearch/test/TestCustomMetadata.java
index 9a549f13ee268..f718de030ea49 100644
--- a/test/framework/src/main/java/org/opensearch/test/TestCustomMetadata.java
+++ b/test/framework/src/main/java/org/opensearch/test/TestCustomMetadata.java
@@ -36,10 +36,10 @@
 import org.opensearch.cluster.AbstractNamedDiffable;
 import org.opensearch.cluster.NamedDiff;
 import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.function.Function;
diff --git a/test/framework/src/main/java/org/opensearch/test/TestSearchContext.java b/test/framework/src/main/java/org/opensearch/test/TestSearchContext.java
index 0e91332892a55..937dc71d55485 100644
--- a/test/framework/src/main/java/org/opensearch/test/TestSearchContext.java
+++ b/test/framework/src/main/java/org/opensearch/test/TestSearchContext.java
@@ -32,6 +32,7 @@
 package org.opensearch.test;
 
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.CollectorManager;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.Query;
 import org.opensearch.action.OriginalIndices;
@@ -39,6 +40,7 @@
 import org.opensearch.action.search.SearchType;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.BigArrays;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexService;
 import org.opensearch.index.cache.bitset.BitsetFilterCache;
 import org.opensearch.index.mapper.MappedFieldType;
@@ -47,10 +49,11 @@
 import org.opensearch.index.query.ParsedQuery;
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.shard.IndexShard;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.search.SearchExtBuilder;
 import org.opensearch.search.SearchShardTarget;
+import org.opensearch.search.aggregations.BucketCollectorProcessor;
+import org.opensearch.search.aggregations.InternalAggregation;
 import org.opensearch.search.aggregations.SearchContextAggregations;
 import org.opensearch.search.collapse.CollapseContext;
 import org.opensearch.search.dfs.DfsSearchResult;
@@ -70,6 +73,7 @@
 import org.opensearch.search.internal.ShardSearchRequest;
 import org.opensearch.search.profile.Profilers;
 import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.search.query.ReduceableSearchResult;
 import org.opensearch.search.rescore.RescoreContext;
 import org.opensearch.search.sort.SortAndFormats;
 import org.opensearch.search.suggest.SuggestionSearchContext;
@@ -90,7 +94,7 @@ public class TestSearchContext extends SearchContext {
     final BigArrays bigArrays;
     final IndexService indexService;
     final BitsetFilterCache fixedBitSetFilterCache;
-    final Map<Class<?>, Collector> queryCollectors = new HashMap<>();
+    final Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers = new HashMap<>();
     final IndexShard indexShard;
     final QuerySearchResult queryResult = new QuerySearchResult();
     final QueryShardContext queryShardContext;
@@ -110,9 +114,22 @@ public class TestSearchContext extends SearchContext {
     private SearchContextAggregations aggregations;
     private ScrollContext scrollContext;
     private FieldDoc searchAfter;
-    private final long originNanoTime = System.nanoTime();
+    private Profilers profilers;
+    private CollapseContext collapse;
+    protected boolean concurrentSegmentSearchEnabled;
+    private BucketCollectorProcessor bucketCollectorProcessor = NO_OP_BUCKET_COLLECTOR_PROCESSOR;
+
+    /**
+     * Sets the concurrent segment search enabled field
+     */
+    public void setConcurrentSegmentSearchEnabled(boolean concurrentSegmentSearchEnabled) {
+        this.concurrentSegmentSearchEnabled = concurrentSegmentSearchEnabled;
+    }
+
     private final Map<String, SearchExtBuilder> searchExtBuilders = new HashMap<>();
 
+    private ShardSearchRequest request;
+
     public TestSearchContext(BigArrays bigArrays, IndexService indexService) {
         this.bigArrays = bigArrays.withCircuitBreaking();
         this.indexService = indexService;
@@ -145,6 +162,7 @@ public TestSearchContext(
         this.indexShard = indexShard;
         this.queryShardContext = queryShardContext;
         this.searcher = searcher;
+        this.concurrentSegmentSearchEnabled = searcher != null && (searcher.getExecutor() != null);
         this.scrollContext = scrollContext;
     }
 
@@ -172,7 +190,11 @@ public String source() {
 
     @Override
     public ShardSearchRequest request() {
-        return null;
+        return request;
+    }
+
+    public void setShardSearchRequest(ShardSearchRequest request) {
+        this.request = request;
     }
 
     @Override
@@ -405,12 +427,13 @@ public FieldDoc searchAfter() {
 
     @Override
     public SearchContext collapse(CollapseContext collapse) {
-        return null;
+        this.collapse = collapse;
+        return this;
     }
 
     @Override
     public CollapseContext collapse() {
-        return null;
+        return collapse;
     }
 
     @Override
@@ -596,12 +619,20 @@ public long getRelativeTimeInMillis() {
 
     @Override
     public Profilers getProfilers() {
-        return null; // no profiling
+        return profilers;
+    }
+
+    /**
+     * Returns concurrent segment search status for the search context
+     */
+    @Override
+    public boolean shouldUseConcurrentSearch() {
+        return concurrentSegmentSearchEnabled;
     }
 
     @Override
-    public Map<Class<?>, Collector> queryCollectors() {
-        return queryCollectors;
+    public Map<Class<?>, CollectorManager<? extends Collector, ReduceableSearchResult>> queryCollectorManagers() {
+        return queryCollectorManagers;
     }
 
     @Override
@@ -633,4 +664,45 @@ public void addRescore(RescoreContext rescore) {
     public ReaderContext readerContext() {
         throw new UnsupportedOperationException();
     }
+
+    @Override
+    public InternalAggregation.ReduceContext partialOnShard() {
+        return InternalAggregationTestCase.emptyReduceContextBuilder().forPartialReduction();
+    }
+
+    @Override
+    public void setBucketCollectorProcessor(BucketCollectorProcessor bucketCollectorProcessor) {
+        this.bucketCollectorProcessor = bucketCollectorProcessor;
+    }
+
+    @Override
+    public BucketCollectorProcessor bucketCollectorProcessor() {
+        return bucketCollectorProcessor;
+    }
+
+    @Override
+    public boolean shouldUseTimeSeriesDescSortOptimization() {
+        return indexShard != null
+            && indexShard.isTimeSeriesDescSortOptimizationEnabled()
+            && sort != null
+            && sort.isSortOnTimeSeriesField()
+            && sort.sort.getSort()[0].getReverse() == false;
+    }
+
+    /**
+     * Clean the query results by consuming all of it
+     */
+    public TestSearchContext withCleanQueryResult() {
+        queryResult.consumeAll();
+        profilers = null;
+        return this;
+    }
+
+    /**
+     * Add profilers to the query
+     */
+    public TestSearchContext withProfilers() {
+        this.profilers = new Profilers(searcher, concurrentSegmentSearchEnabled);
+        return this;
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/VersionUtils.java b/test/framework/src/main/java/org/opensearch/test/VersionUtils.java
index 1e6807189f947..bd7ce2b0f876d 100644
--- a/test/framework/src/main/java/org/opensearch/test/VersionUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/VersionUtils.java
@@ -65,7 +65,7 @@ static Tuple<List<Version>, List<Version>> resolveReleasedVersions(Version curre
         Map<Integer, List<Version>> majorVersions = Version.getDeclaredVersions(versionClass)
             .stream()
             .collect(Collectors.groupingBy(v -> (int) v.major));
-        // this breaks b/c 5.x is still in version list but master doesn't care about it!
+        // this breaks b/c 5.x is still in version list but cluster-manager doesn't care about it!
         // assert majorVersions.size() == 2;
         List<List<Version>> oldVersions = new ArrayList<>(0);
         List<List<Version>> previousMajor = new ArrayList<>(0);
@@ -85,11 +85,11 @@ static Tuple<List<Version>, List<Version>> resolveReleasedVersions(Version curre
         List<Version> unreleasedVersions = new ArrayList<>();
         final List<List<Version>> stableVersions;
         if (currentMajor.size() == 1) {
-            // on master branch
+            // on main branch
             stableVersions = previousMajor;
             // remove current
             moveLastToUnreleased(currentMajor, unreleasedVersions);
-        } else if (current.major != 1 && current.major != 2) {
+        } else if (current.major != 1) {
             // on a stable or release branch, ie N.x
             stableVersions = currentMajor;
             // remove the next maintenance bugfix
diff --git a/test/framework/src/main/java/org/opensearch/test/XContentTestUtils.java b/test/framework/src/main/java/org/opensearch/test/XContentTestUtils.java
index 5945ac01b4547..c6fe67ce8fff8 100644
--- a/test/framework/src/main/java/org/opensearch/test/XContentTestUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/XContentTestUtils.java
@@ -32,17 +32,19 @@
 
 package org.opensearch.test;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.yaml.ObjectPath;
 
 import java.io.IOException;
@@ -56,9 +58,9 @@
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
-import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomAsciiOfLength;
-import static org.opensearch.common.xcontent.ToXContent.EMPTY_PARAMS;
 import static org.opensearch.common.xcontent.XContentHelper.createParser;
+import static org.opensearch.core.xcontent.ToXContent.EMPTY_PARAMS;
+import static com.carrotsearch.randomizedtesting.generators.RandomStrings.randomAsciiOfLength;
 
 public final class XContentTestUtils {
     private XContentTestUtils() {
@@ -74,7 +76,7 @@ public static Map<String, Object> convertToMap(ToXContent part) throws IOExcepti
     }
 
     public static BytesReference convertToXContent(Map<String, ?> map, XContentType xContentType) throws IOException {
-        try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(xContentType)) {
             builder.map(map);
             return BytesReference.bytes(builder);
         }
@@ -202,7 +204,7 @@ private static String differenceBetweenObjectsIgnoringArrayOrder(String path, Ob
      * </pre>
      */
     public static BytesReference insertRandomFields(
-        XContentType contentType,
+        MediaType contentType,
         BytesReference xContent,
         Predicate<String> excludeFilter,
         Random random
diff --git a/test/framework/src/main/java/org/opensearch/test/client/NoOpClient.java b/test/framework/src/main/java/org/opensearch/test/client/NoOpClient.java
index cc274f4dd0be3..a0e87d5fd7189 100644
--- a/test/framework/src/main/java/org/opensearch/test/client/NoOpClient.java
+++ b/test/framework/src/main/java/org/opensearch/test/client/NoOpClient.java
@@ -33,12 +33,12 @@
 package org.opensearch.test.client;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
 import org.opensearch.client.support.AbstractClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/client/NoOpNodeClient.java b/test/framework/src/main/java/org/opensearch/test/client/NoOpNodeClient.java
index 413c78ba37026..7dfe9298e9a92 100644
--- a/test/framework/src/main/java/org/opensearch/test/client/NoOpNodeClient.java
+++ b/test/framework/src/main/java/org/opensearch/test/client/NoOpNodeClient.java
@@ -33,22 +33,21 @@
 package org.opensearch.test.client;
 
 import org.opensearch.OpenSearchException;
-import org.opensearch.action.ActionListener;
+import org.opensearch.action.ActionModule.DynamicActionRegistry;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
-import org.opensearch.action.support.TransportAction;
 import org.opensearch.client.Client;
 import org.opensearch.client.node.NodeClient;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskListener;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.RemoteClusterService;
 
-import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 
@@ -86,7 +85,7 @@ public <Request extends ActionRequest, Response extends ActionResponse> void doE
 
     @Override
     public void initialize(
-        Map<ActionType, TransportAction> actions,
+        DynamicActionRegistry dynamicActionRegistry,
         Supplier<String> localNodeId,
         RemoteClusterService remoteClusterService,
         NamedWriteableRegistry namedWriteableRegistry
diff --git a/test/framework/src/main/java/org/opensearch/test/client/RandomizingClient.java b/test/framework/src/main/java/org/opensearch/test/client/RandomizingClient.java
index e0e916c6da0f1..0ef7c5dffcb5e 100644
--- a/test/framework/src/main/java/org/opensearch/test/client/RandomizingClient.java
+++ b/test/framework/src/main/java/org/opensearch/test/client/RandomizingClient.java
@@ -33,6 +33,7 @@
 package org.opensearch.test.client;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.lucene.tests.util.TestUtil;
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchType;
@@ -42,6 +43,7 @@
 import org.opensearch.common.unit.TimeValue;
 
 import java.util.Arrays;
+import java.util.EnumSet;
 import java.util.Random;
 import java.util.concurrent.TimeUnit;
 
@@ -61,7 +63,7 @@ public RandomizingClient(Client client, Random random) {
         // given that they return `size*num_shards` hits instead of `size`
         defaultSearchType = RandomPicks.randomFrom(random, Arrays.asList(SearchType.DFS_QUERY_THEN_FETCH, SearchType.QUERY_THEN_FETCH));
         if (random.nextInt(10) == 0) {
-            defaultPreference = Preference.LOCAL.type();
+            defaultPreference = RandomPicks.randomFrom(random, EnumSet.of(Preference.PRIMARY_FIRST, Preference.LOCAL)).type();
         } else if (random.nextInt(10) == 0) {
             String s = TestUtil.randomRealisticUnicodeString(random, 1, 10);
             defaultPreference = s.startsWith("_") ? null : s; // '_' is a reserved character
diff --git a/test/framework/src/main/java/org/opensearch/test/core/compress/AbstractCompressorTestCase.java b/test/framework/src/main/java/org/opensearch/test/core/compress/AbstractCompressorTestCase.java
new file mode 100644
index 0000000000000..be53e46122157
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/core/compress/AbstractCompressorTestCase.java
@@ -0,0 +1,409 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.core.compress;
+
+import org.apache.lucene.tests.util.LineFileDocs;
+import org.apache.lucene.tests.util.TestUtil;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Random;
+import java.util.concurrent.CountDownLatch;
+
+public abstract class AbstractCompressorTestCase extends OpenSearchTestCase {
+
+    public void testRandom() throws IOException {
+        Random r = random();
+        for (int i = 0; i < 10; i++) {
+            final byte[] bytes = new byte[TestUtil.nextInt(r, 1, 100000)];
+            r.nextBytes(bytes);
+            doTest(bytes);
+        }
+    }
+
+    public void testRandomThreads() throws Exception {
+        final Random r = random();
+        int threadCount = TestUtil.nextInt(r, 2, 6);
+        Thread[] threads = new Thread[threadCount];
+        final CountDownLatch startingGun = new CountDownLatch(1);
+        for (int tid = 0; tid < threadCount; tid++) {
+            final long seed = r.nextLong();
+            threads[tid] = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        Random r = new Random(seed);
+                        startingGun.await();
+                        for (int i = 0; i < 10; i++) {
+                            byte bytes[] = new byte[TestUtil.nextInt(r, 1, 100000)];
+                            r.nextBytes(bytes);
+                            doTest(bytes);
+                        }
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            };
+            threads[tid].start();
+        }
+        startingGun.countDown();
+        for (Thread t : threads) {
+            t.join();
+        }
+    }
+
+    public void testLineDocs() throws IOException {
+        Random r = random();
+        LineFileDocs lineFileDocs = new LineFileDocs(r);
+        for (int i = 0; i < 10; i++) {
+            int numDocs = TestUtil.nextInt(r, 1, 200);
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            for (int j = 0; j < numDocs; j++) {
+                String s = lineFileDocs.nextDoc().get("body");
+                bos.write(s.getBytes(StandardCharsets.UTF_8));
+            }
+            doTest(bos.toByteArray());
+        }
+        lineFileDocs.close();
+    }
+
+    public void testLineDocsThreads() throws Exception {
+        final Random r = random();
+        int threadCount = TestUtil.nextInt(r, 2, 6);
+        Thread[] threads = new Thread[threadCount];
+        final CountDownLatch startingGun = new CountDownLatch(1);
+        for (int tid = 0; tid < threadCount; tid++) {
+            final long seed = r.nextLong();
+            threads[tid] = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        Random r = new Random(seed);
+                        startingGun.await();
+                        LineFileDocs lineFileDocs = new LineFileDocs(r);
+                        for (int i = 0; i < 10; i++) {
+                            int numDocs = TestUtil.nextInt(r, 1, 200);
+                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                            for (int j = 0; j < numDocs; j++) {
+                                String s = lineFileDocs.nextDoc().get("body");
+                                bos.write(s.getBytes(StandardCharsets.UTF_8));
+                            }
+                            doTest(bos.toByteArray());
+                        }
+                        lineFileDocs.close();
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            };
+            threads[tid].start();
+        }
+        startingGun.countDown();
+        for (Thread t : threads) {
+            t.join();
+        }
+    }
+
+    public void testRepetitionsL() throws IOException {
+        Random r = random();
+        for (int i = 0; i < 10; i++) {
+            int numLongs = TestUtil.nextInt(r, 1, 10000);
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            long theValue = r.nextLong();
+            for (int j = 0; j < numLongs; j++) {
+                if (r.nextInt(10) == 0) {
+                    theValue = r.nextLong();
+                }
+                bos.write((byte) (theValue >>> 56));
+                bos.write((byte) (theValue >>> 48));
+                bos.write((byte) (theValue >>> 40));
+                bos.write((byte) (theValue >>> 32));
+                bos.write((byte) (theValue >>> 24));
+                bos.write((byte) (theValue >>> 16));
+                bos.write((byte) (theValue >>> 8));
+                bos.write((byte) theValue);
+            }
+            doTest(bos.toByteArray());
+        }
+    }
+
+    public void testRepetitionsLThreads() throws Exception {
+        final Random r = random();
+        int threadCount = TestUtil.nextInt(r, 2, 6);
+        Thread[] threads = new Thread[threadCount];
+        final CountDownLatch startingGun = new CountDownLatch(1);
+        for (int tid = 0; tid < threadCount; tid++) {
+            final long seed = r.nextLong();
+            threads[tid] = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        Random r = new Random(seed);
+                        startingGun.await();
+                        for (int i = 0; i < 10; i++) {
+                            int numLongs = TestUtil.nextInt(r, 1, 10000);
+                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                            long theValue = r.nextLong();
+                            for (int j = 0; j < numLongs; j++) {
+                                if (r.nextInt(10) == 0) {
+                                    theValue = r.nextLong();
+                                }
+                                bos.write((byte) (theValue >>> 56));
+                                bos.write((byte) (theValue >>> 48));
+                                bos.write((byte) (theValue >>> 40));
+                                bos.write((byte) (theValue >>> 32));
+                                bos.write((byte) (theValue >>> 24));
+                                bos.write((byte) (theValue >>> 16));
+                                bos.write((byte) (theValue >>> 8));
+                                bos.write((byte) theValue);
+                            }
+                            doTest(bos.toByteArray());
+                        }
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            };
+            threads[tid].start();
+        }
+        startingGun.countDown();
+        for (Thread t : threads) {
+            t.join();
+        }
+    }
+
+    public void testRepetitionsI() throws IOException {
+        Random r = random();
+        for (int i = 0; i < 10; i++) {
+            int numInts = TestUtil.nextInt(r, 1, 20000);
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            int theValue = r.nextInt();
+            for (int j = 0; j < numInts; j++) {
+                if (r.nextInt(10) == 0) {
+                    theValue = r.nextInt();
+                }
+                bos.write((byte) (theValue >>> 24));
+                bos.write((byte) (theValue >>> 16));
+                bos.write((byte) (theValue >>> 8));
+                bos.write((byte) theValue);
+            }
+            doTest(bos.toByteArray());
+        }
+    }
+
+    public void testRepetitionsIThreads() throws Exception {
+        final Random r = random();
+        int threadCount = TestUtil.nextInt(r, 2, 6);
+        Thread[] threads = new Thread[threadCount];
+        final CountDownLatch startingGun = new CountDownLatch(1);
+        for (int tid = 0; tid < threadCount; tid++) {
+            final long seed = r.nextLong();
+            threads[tid] = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        Random r = new Random(seed);
+                        startingGun.await();
+                        for (int i = 0; i < 10; i++) {
+                            int numInts = TestUtil.nextInt(r, 1, 20000);
+                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                            int theValue = r.nextInt();
+                            for (int j = 0; j < numInts; j++) {
+                                if (r.nextInt(10) == 0) {
+                                    theValue = r.nextInt();
+                                }
+                                bos.write((byte) (theValue >>> 24));
+                                bos.write((byte) (theValue >>> 16));
+                                bos.write((byte) (theValue >>> 8));
+                                bos.write((byte) theValue);
+                            }
+                            doTest(bos.toByteArray());
+                        }
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            };
+            threads[tid].start();
+        }
+        startingGun.countDown();
+        for (Thread t : threads) {
+            t.join();
+        }
+    }
+
+    public void testRepetitionsS() throws IOException {
+        Random r = random();
+        for (int i = 0; i < 10; i++) {
+            int numShorts = TestUtil.nextInt(r, 1, 40000);
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            short theValue = (short) r.nextInt(65535);
+            for (int j = 0; j < numShorts; j++) {
+                if (r.nextInt(10) == 0) {
+                    theValue = (short) r.nextInt(65535);
+                }
+                bos.write((byte) (theValue >>> 8));
+                bos.write((byte) theValue);
+            }
+            doTest(bos.toByteArray());
+        }
+    }
+
+    public void testMixed() throws IOException {
+        Random r = random();
+        LineFileDocs lineFileDocs = new LineFileDocs(r);
+        for (int i = 0; i < 2; ++i) {
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            int prevInt = r.nextInt();
+            long prevLong = r.nextLong();
+            while (bos.size() < 400000) {
+                switch (r.nextInt(4)) {
+                    case 0:
+                        addInt(r, prevInt, bos);
+                        break;
+                    case 1:
+                        addLong(r, prevLong, bos);
+                        break;
+                    case 2:
+                        addString(lineFileDocs, bos);
+                        break;
+                    case 3:
+                        addBytes(r, bos);
+                        break;
+                    default:
+                        throw new IllegalStateException("Random is broken");
+                }
+            }
+            doTest(bos.toByteArray());
+        }
+    }
+
+    private void addLong(Random r, long prev, ByteArrayOutputStream bos) {
+        long theValue = prev;
+        if (r.nextInt(10) != 0) {
+            theValue = r.nextLong();
+        }
+        bos.write((byte) (theValue >>> 56));
+        bos.write((byte) (theValue >>> 48));
+        bos.write((byte) (theValue >>> 40));
+        bos.write((byte) (theValue >>> 32));
+        bos.write((byte) (theValue >>> 24));
+        bos.write((byte) (theValue >>> 16));
+        bos.write((byte) (theValue >>> 8));
+        bos.write((byte) theValue);
+    }
+
+    private void addInt(Random r, int prev, ByteArrayOutputStream bos) {
+        int theValue = prev;
+        if (r.nextInt(10) != 0) {
+            theValue = r.nextInt();
+        }
+        bos.write((byte) (theValue >>> 24));
+        bos.write((byte) (theValue >>> 16));
+        bos.write((byte) (theValue >>> 8));
+        bos.write((byte) theValue);
+    }
+
+    private void addString(LineFileDocs lineFileDocs, ByteArrayOutputStream bos) throws IOException {
+        String s = lineFileDocs.nextDoc().get("body");
+        bos.write(s.getBytes(StandardCharsets.UTF_8));
+    }
+
+    private void addBytes(Random r, ByteArrayOutputStream bos) throws IOException {
+        byte bytes[] = new byte[TestUtil.nextInt(r, 1, 10000)];
+        r.nextBytes(bytes);
+        bos.write(bytes);
+    }
+
+    public void testRepetitionsSThreads() throws Exception {
+        final Random r = random();
+        int threadCount = TestUtil.nextInt(r, 2, 6);
+        Thread[] threads = new Thread[threadCount];
+        final CountDownLatch startingGun = new CountDownLatch(1);
+        for (int tid = 0; tid < threadCount; tid++) {
+            final long seed = r.nextLong();
+            threads[tid] = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        Random r = new Random(seed);
+                        startingGun.await();
+                        for (int i = 0; i < 10; i++) {
+                            int numShorts = TestUtil.nextInt(r, 1, 40000);
+                            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                            short theValue = (short) r.nextInt(65535);
+                            for (int j = 0; j < numShorts; j++) {
+                                if (r.nextInt(10) == 0) {
+                                    theValue = (short) r.nextInt(65535);
+                                }
+                                bos.write((byte) (theValue >>> 8));
+                                bos.write((byte) theValue);
+                            }
+                            doTest(bos.toByteArray());
+                        }
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+            };
+            threads[tid].start();
+        }
+        startingGun.countDown();
+        for (Thread t : threads) {
+            t.join();
+        }
+    }
+
+    private void doTest(byte bytes[]) throws IOException {
+        InputStream rawIn = new ByteArrayInputStream(bytes);
+        Compressor c = compressor();
+
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        final Random r = random();
+        int bufferSize = r.nextBoolean() ? 65535 : TestUtil.nextInt(random(), 1, 70000);
+        int prepadding = r.nextInt(70000);
+        int postpadding = r.nextInt(70000);
+        byte[] buffer = new byte[prepadding + bufferSize + postpadding];
+        int len;
+        try (OutputStream os = c.threadLocalOutputStream(bos)) {
+            r.nextBytes(buffer); // fill block completely with junk
+            while ((len = rawIn.read(buffer, prepadding, bufferSize)) != -1) {
+                os.write(buffer, prepadding, len);
+            }
+        }
+        rawIn.close();
+
+        // now we have compressed byte array
+        InputStream in = c.threadLocalInputStream(new ByteArrayInputStream(bos.toByteArray()));
+
+        // randomize constants again
+        bufferSize = r.nextBoolean() ? 65535 : TestUtil.nextInt(random(), 1, 70000);
+        prepadding = r.nextInt(70000);
+        postpadding = r.nextInt(70000);
+        buffer = new byte[prepadding + bufferSize + postpadding];
+        r.nextBytes(buffer); // fill block completely with junk
+
+        ByteArrayOutputStream uncompressedOut = new ByteArrayOutputStream();
+        while ((len = in.read(buffer, prepadding, bufferSize)) != -1) {
+            uncompressedOut.write(buffer, prepadding, len);
+        }
+        uncompressedOut.close();
+
+        assertArrayEquals(bytes, uncompressedOut.toByteArray());
+    }
+
+    protected abstract Compressor compressor();
+
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/BlockClusterManagerServiceOnClusterManager.java b/test/framework/src/main/java/org/opensearch/test/disruption/BlockClusterManagerServiceOnClusterManager.java
new file mode 100644
index 0000000000000..3d166b1590a5b
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/BlockClusterManagerServiceOnClusterManager.java
@@ -0,0 +1,117 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.test.disruption;
+
+import org.apache.logging.log4j.core.util.Throwables;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.InternalTestCluster;
+
+import java.util.Random;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicReference;
+
+public class BlockClusterManagerServiceOnClusterManager extends SingleNodeDisruption {
+
+    AtomicReference<CountDownLatch> disruptionLatch = new AtomicReference<>();
+
+    public BlockClusterManagerServiceOnClusterManager(Random random) {
+        super(random);
+    }
+
+    @Override
+    public void startDisrupting() {
+        disruptedNode = cluster.getClusterManagerName();
+        final String disruptionNodeCopy = disruptedNode;
+        if (disruptionNodeCopy == null) {
+            return;
+        }
+        ClusterService clusterService = cluster.getInstance(ClusterService.class, disruptionNodeCopy);
+        if (clusterService == null) {
+            return;
+        }
+        logger.info("blocking cluster-manager service on node [{}]", disruptionNodeCopy);
+        boolean success = disruptionLatch.compareAndSet(null, new CountDownLatch(1));
+        assert success : "startDisrupting called without waiting on stopDisrupting to complete";
+        final CountDownLatch started = new CountDownLatch(1);
+        clusterService.getClusterManagerService().submitStateUpdateTask("service_disruption_block", new ClusterStateUpdateTask() {
+            @Override
+            public Priority priority() {
+                return Priority.IMMEDIATE;
+            }
+
+            @Override
+            public ClusterState execute(ClusterState currentState) throws Exception {
+                started.countDown();
+                CountDownLatch latch = disruptionLatch.get();
+                if (latch != null) {
+                    try {
+                        latch.await();
+                    } catch (InterruptedException e) {
+                        Throwables.rethrow(e);
+                    }
+                }
+                return currentState;
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error("unexpected error during disruption", e);
+            }
+        });
+        try {
+            started.await();
+        } catch (InterruptedException e) {}
+    }
+
+    @Override
+    public void stopDisrupting() {
+        CountDownLatch latch = disruptionLatch.get();
+        if (latch != null) {
+            latch.countDown();
+        }
+
+    }
+
+    @Override
+    public void removeAndEnsureHealthy(InternalTestCluster cluster) {
+        removeFromCluster(cluster);
+    }
+
+    @Override
+    public TimeValue expectedTimeToHeal() {
+        return TimeValue.timeValueMinutes(0);
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/BlockMasterServiceOnMaster.java b/test/framework/src/main/java/org/opensearch/test/disruption/BlockMasterServiceOnMaster.java
index 99397f0ffd953..bbe99d838f296 100644
--- a/test/framework/src/main/java/org/opensearch/test/disruption/BlockMasterServiceOnMaster.java
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/BlockMasterServiceOnMaster.java
@@ -6,112 +6,16 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.test.disruption;
 
-import org.apache.logging.log4j.core.util.Throwables;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.Priority;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.InternalTestCluster;
-
 import java.util.Random;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicReference;
-
-public class BlockMasterServiceOnMaster extends SingleNodeDisruption {
-
-    AtomicReference<CountDownLatch> disruptionLatch = new AtomicReference<>();
 
+/**
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link BlockClusterManagerServiceOnClusterManager}
+ */
+@Deprecated
+public class BlockMasterServiceOnMaster extends BlockClusterManagerServiceOnClusterManager {
     public BlockMasterServiceOnMaster(Random random) {
         super(random);
     }
-
-    @Override
-    public void startDisrupting() {
-        disruptedNode = cluster.getMasterName();
-        final String disruptionNodeCopy = disruptedNode;
-        if (disruptionNodeCopy == null) {
-            return;
-        }
-        ClusterService clusterService = cluster.getInstance(ClusterService.class, disruptionNodeCopy);
-        if (clusterService == null) {
-            return;
-        }
-        logger.info("blocking master service on node [{}]", disruptionNodeCopy);
-        boolean success = disruptionLatch.compareAndSet(null, new CountDownLatch(1));
-        assert success : "startDisrupting called without waiting on stopDisrupting to complete";
-        final CountDownLatch started = new CountDownLatch(1);
-        clusterService.getMasterService().submitStateUpdateTask("service_disruption_block", new ClusterStateUpdateTask() {
-            @Override
-            public Priority priority() {
-                return Priority.IMMEDIATE;
-            }
-
-            @Override
-            public ClusterState execute(ClusterState currentState) throws Exception {
-                started.countDown();
-                CountDownLatch latch = disruptionLatch.get();
-                if (latch != null) {
-                    try {
-                        latch.await();
-                    } catch (InterruptedException e) {
-                        Throwables.rethrow(e);
-                    }
-                }
-                return currentState;
-            }
-
-            @Override
-            public void onFailure(String source, Exception e) {
-                logger.error("unexpected error during disruption", e);
-            }
-        });
-        try {
-            started.await();
-        } catch (InterruptedException e) {}
-    }
-
-    @Override
-    public void stopDisrupting() {
-        CountDownLatch latch = disruptionLatch.get();
-        if (latch != null) {
-            latch.countDown();
-        }
-
-    }
-
-    @Override
-    public void removeAndEnsureHealthy(InternalTestCluster cluster) {
-        removeFromCluster(cluster);
-    }
-
-    @Override
-    public TimeValue expectedTimeToHeal() {
-        return TimeValue.timeValueMinutes(0);
-    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/BusyClusterManagerServiceDisruption.java b/test/framework/src/main/java/org/opensearch/test/disruption/BusyClusterManagerServiceDisruption.java
new file mode 100644
index 0000000000000..5e538d09c5ebd
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/BusyClusterManagerServiceDisruption.java
@@ -0,0 +1,100 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.test.disruption;
+
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.Priority;
+import org.opensearch.common.unit.TimeValue;
+import org.opensearch.test.InternalTestCluster;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class BusyClusterManagerServiceDisruption extends SingleNodeDisruption {
+    private final AtomicBoolean active = new AtomicBoolean();
+    private final Priority priority;
+
+    public BusyClusterManagerServiceDisruption(Random random, Priority priority) {
+        super(random);
+        this.priority = priority;
+    }
+
+    @Override
+    public void startDisrupting() {
+        disruptedNode = cluster.getClusterManagerName();
+        final String disruptionNodeCopy = disruptedNode;
+        if (disruptionNodeCopy == null) {
+            return;
+        }
+        ClusterService clusterService = cluster.getInstance(ClusterService.class, disruptionNodeCopy);
+        if (clusterService == null) {
+            return;
+        }
+        logger.info("making cluster-manager service busy on node [{}] at priority [{}]", disruptionNodeCopy, priority);
+        active.set(true);
+        submitTask(clusterService);
+    }
+
+    private void submitTask(ClusterService clusterService) {
+        clusterService.getClusterManagerService().submitStateUpdateTask("service_disruption_block", new ClusterStateUpdateTask(priority) {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                if (active.get()) {
+                    submitTask(clusterService);
+                }
+                return currentState;
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                logger.error("unexpected error during disruption", e);
+            }
+        });
+    }
+
+    @Override
+    public void stopDisrupting() {
+        active.set(false);
+    }
+
+    @Override
+    public void removeAndEnsureHealthy(InternalTestCluster cluster) {
+        removeFromCluster(cluster);
+    }
+
+    @Override
+    public TimeValue expectedTimeToHeal() {
+        return TimeValue.timeValueMinutes(0);
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/BusyMasterServiceDisruption.java b/test/framework/src/main/java/org/opensearch/test/disruption/BusyMasterServiceDisruption.java
index 65cc0dac47a2b..884997123e6a4 100644
--- a/test/framework/src/main/java/org/opensearch/test/disruption/BusyMasterServiceDisruption.java
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/BusyMasterServiceDisruption.java
@@ -6,95 +6,18 @@
  * compatible open source license.
  */
 
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
 package org.opensearch.test.disruption;
 
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
-import org.opensearch.common.unit.TimeValue;
-import org.opensearch.test.InternalTestCluster;
 
 import java.util.Random;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-public class BusyMasterServiceDisruption extends SingleNodeDisruption {
-    private final AtomicBoolean active = new AtomicBoolean();
-    private final Priority priority;
 
+/**
+ * @deprecated As of 2.2, because supporting inclusive language, replaced by {@link BusyClusterManagerServiceDisruption}
+ */
+@Deprecated
+public class BusyMasterServiceDisruption extends BusyClusterManagerServiceDisruption {
     public BusyMasterServiceDisruption(Random random, Priority priority) {
-        super(random);
-        this.priority = priority;
-    }
-
-    @Override
-    public void startDisrupting() {
-        disruptedNode = cluster.getMasterName();
-        final String disruptionNodeCopy = disruptedNode;
-        if (disruptionNodeCopy == null) {
-            return;
-        }
-        ClusterService clusterService = cluster.getInstance(ClusterService.class, disruptionNodeCopy);
-        if (clusterService == null) {
-            return;
-        }
-        logger.info("making master service busy on node [{}] at priority [{}]", disruptionNodeCopy, priority);
-        active.set(true);
-        submitTask(clusterService);
-    }
-
-    private void submitTask(ClusterService clusterService) {
-        clusterService.getMasterService().submitStateUpdateTask("service_disruption_block", new ClusterStateUpdateTask(priority) {
-            @Override
-            public ClusterState execute(ClusterState currentState) {
-                if (active.get()) {
-                    submitTask(clusterService);
-                }
-                return currentState;
-            }
-
-            @Override
-            public void onFailure(String source, Exception e) {
-                logger.error("unexpected error during disruption", e);
-            }
-        });
-    }
-
-    @Override
-    public void stopDisrupting() {
-        active.set(false);
-    }
-
-    @Override
-    public void removeAndEnsureHealthy(InternalTestCluster cluster) {
-        removeFromCluster(cluster);
-    }
-
-    @Override
-    public TimeValue expectedTimeToHeal() {
-        return TimeValue.timeValueMinutes(0);
+        super(random, priority);
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/DisruptableMockTransport.java b/test/framework/src/main/java/org/opensearch/test/disruption/DisruptableMockTransport.java
index dd025555d1ae8..4f3884f97a570 100644
--- a/test/framework/src/main/java/org/opensearch/test/disruption/DisruptableMockTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/DisruptableMockTransport.java
@@ -33,14 +33,16 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.test.transport.MockTransport;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.CloseableConnection;
@@ -52,7 +54,6 @@
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
@@ -91,9 +92,10 @@ public TransportService createTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
-        return new TransportService(settings, this, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders);
+        return new TransportService(settings, this, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders, tracer);
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/opensearch/test/disruption/NetworkDisruption.java b/test/framework/src/main/java/org/opensearch/test/disruption/NetworkDisruption.java
index b3877b202d36d..e77b8f5b24897 100644
--- a/test/framework/src/main/java/org/opensearch/test/disruption/NetworkDisruption.java
+++ b/test/framework/src/main/java/org/opensearch/test/disruption/NetworkDisruption.java
@@ -33,6 +33,7 @@
 package org.opensearch.test.disruption;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.ClusterState;
@@ -109,7 +110,7 @@ public void ensureHealthy(InternalTestCluster cluster) {
     /**
      * Ensures that all nodes in the cluster are connected to each other.
      *
-     * Some network disruptions may leave nodes that are not the master disconnected from each other.
+     * Some network disruptions may leave nodes that are not the cluster-manager disconnected from each other.
      * {@link org.opensearch.cluster.NodeConnectionsService} will eventually reconnect but it's
      * handy to be able to ensure this happens faster
      */
diff --git a/test/framework/src/main/java/org/opensearch/test/engine/MockEngineSupport.java b/test/framework/src/main/java/org/opensearch/test/engine/MockEngineSupport.java
index f2427dfda2742..86e92a3deef75 100644
--- a/test/framework/src/main/java/org/opensearch/test/engine/MockEngineSupport.java
+++ b/test/framework/src/main/java/org/opensearch/test/engine/MockEngineSupport.java
@@ -33,19 +33,19 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.FilterDirectoryReader;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.tests.index.AssertingDirectoryReader;
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.engine.EngineConfig;
 import org.opensearch.index.engine.EngineException;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.io.Closeable;
diff --git a/test/framework/src/main/java/org/opensearch/test/fixture/AbstractHttpFixture.java b/test/framework/src/main/java/org/opensearch/test/fixture/AbstractHttpFixture.java
index 9ccbb53c6a96a..c52eb75ce666f 100644
--- a/test/framework/src/main/java/org/opensearch/test/fixture/AbstractHttpFixture.java
+++ b/test/framework/src/main/java/org/opensearch/test/fixture/AbstractHttpFixture.java
@@ -33,6 +33,7 @@
 package org.opensearch.test.fixture;
 
 import com.sun.net.httpserver.HttpServer;
+
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/gateway/TestGatewayAllocator.java b/test/framework/src/main/java/org/opensearch/test/gateway/TestGatewayAllocator.java
index 54c92f4d519aa..107e42ce43487 100644
--- a/test/framework/src/main/java/org/opensearch/test/gateway/TestGatewayAllocator.java
+++ b/test/framework/src/main/java/org/opensearch/test/gateway/TestGatewayAllocator.java
@@ -37,12 +37,13 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.FailedShard;
 import org.opensearch.cluster.routing.allocation.RoutingAllocation;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.gateway.AsyncShardFetch;
 import org.opensearch.gateway.GatewayAllocator;
 import org.opensearch.gateway.PrimaryShardAllocator;
 import org.opensearch.gateway.ReplicaShardAllocator;
 import org.opensearch.gateway.TransportNodesListGatewayStartedShards.NodeGatewayStartedShards;
-import org.opensearch.index.shard.ShardId;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata.NodeStoreFilesMetadata;
 
 import java.util.Collections;
@@ -71,6 +72,7 @@ public class TestGatewayAllocator extends GatewayAllocator {
 
     Map<String /* node id */, Map<ShardId, ShardRouting>> knownAllocations = new HashMap<>();
     DiscoveryNodes currentNodes = DiscoveryNodes.EMPTY_NODES;
+    Map<String, ReplicationCheckpoint> shardIdNodeToReplicationCheckPointMap = new HashMap<>();
 
     PrimaryShardAllocator primaryShardAllocator = new PrimaryShardAllocator() {
         @Override
@@ -90,7 +92,8 @@ protected AsyncShardFetch.FetchResult<NodeGatewayStartedShards> fetchData(ShardR
                         routing -> new NodeGatewayStartedShards(
                             currentNodes.get(routing.currentNodeId()),
                             routing.allocationId().getId(),
-                            routing.primary()
+                            routing.primary(),
+                            getReplicationCheckpoint(shardId, routing.currentNodeId())
                         )
                     )
                 );
@@ -99,6 +102,10 @@ protected AsyncShardFetch.FetchResult<NodeGatewayStartedShards> fetchData(ShardR
         }
     };
 
+    private ReplicationCheckpoint getReplicationCheckpoint(ShardId shardId, String nodeName) {
+        return shardIdNodeToReplicationCheckPointMap.getOrDefault(getReplicationCheckPointKey(shardId, nodeName), null);
+    }
+
     ReplicaShardAllocator replicaShardAllocator = new ReplicaShardAllocator() {
         @Override
         protected AsyncShardFetch.FetchResult<NodeStoreFilesMetadata> fetchData(ShardRouting shard, RoutingAllocation allocation) {
@@ -156,4 +163,12 @@ public void allocateUnassigned(
     public void addKnownAllocation(ShardRouting shard) {
         knownAllocations.computeIfAbsent(shard.currentNodeId(), id -> new HashMap<>()).put(shard.shardId(), shard);
     }
+
+    public String getReplicationCheckPointKey(ShardId shardId, String nodeName) {
+        return shardId.toString() + "_" + nodeName;
+    }
+
+    public void addReplicationCheckpoint(ShardId shardId, String nodeName, ReplicationCheckpoint replicationCheckpoint) {
+        shardIdNodeToReplicationCheckPointMap.putIfAbsent(getReplicationCheckPointKey(shardId, nodeName), replicationCheckpoint);
+    }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionAssertions.java b/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionAssertions.java
deleted file mode 100644
index ca000ef5b460c..0000000000000
--- a/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionAssertions.java
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.test.hamcrest;
-
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.hamcrest.Matcher;
-
-/**
- * Assertions for easier handling of our custom collections,
- * for example ImmutableOpenMap
- */
-public class CollectionAssertions {
-
-    public static Matcher<ImmutableOpenMap> hasKey(final String key) {
-        return new CollectionMatchers.ImmutableOpenMapHasKeyMatcher(key);
-    }
-
-    public static Matcher<ImmutableOpenMap> hasAllKeys(final String... keys) {
-        return new CollectionMatchers.ImmutableOpenMapHasAllKeysMatcher(keys);
-    }
-}
diff --git a/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionMatchers.java b/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionMatchers.java
deleted file mode 100644
index 733cd4a21acca..0000000000000
--- a/test/framework/src/main/java/org/opensearch/test/hamcrest/CollectionMatchers.java
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.test.hamcrest;
-
-import org.opensearch.common.collect.ImmutableOpenMap;
-import org.hamcrest.Description;
-import org.hamcrest.TypeSafeMatcher;
-
-import java.util.Arrays;
-import java.util.List;
-
-/**
- * Matchers for easier handling of our custom collections,
- * for example ImmutableOpenMap
- */
-public class CollectionMatchers {
-
-    public static class ImmutableOpenMapHasKeyMatcher extends TypeSafeMatcher<ImmutableOpenMap> {
-
-        private final String key;
-
-        public ImmutableOpenMapHasKeyMatcher(String key) {
-            this.key = key;
-        }
-
-        @Override
-        protected boolean matchesSafely(ImmutableOpenMap item) {
-            return item.containsKey(key);
-        }
-
-        @Override
-        public void describeMismatchSafely(final ImmutableOpenMap map, final Description mismatchDescription) {
-            if (map.size() == 0) {
-                mismatchDescription.appendText("was empty");
-            } else {
-                mismatchDescription.appendText(" was ").appendValue(map);
-            }
-        }
-
-        @Override
-        public void describeTo(Description description) {
-            description.appendText("ImmutableOpenMap should contain key " + key);
-        }
-    }
-
-    public static class ImmutableOpenMapHasAllKeysMatcher extends TypeSafeMatcher<ImmutableOpenMap> {
-
-        private final List<String> keys;
-        private String missingKey;
-
-        public ImmutableOpenMapHasAllKeysMatcher(final String... keys) {
-            this.keys = Arrays.asList(keys);
-        }
-
-        @Override
-        protected boolean matchesSafely(ImmutableOpenMap item) {
-            for (String key : keys) {
-                if (!item.containsKey(key)) {
-                    missingKey = key;
-                    return false;
-                }
-            }
-
-            return true;
-        }
-
-        @Override
-        public void describeMismatchSafely(final ImmutableOpenMap map, final Description mismatchDescription) {
-            if (map.size() == 0) {
-                mismatchDescription.appendText("was empty");
-            } else {
-                mismatchDescription.appendText("was ").appendValue(map.keys());
-            }
-        }
-
-        @Override
-        public void describeTo(Description description) {
-            description.appendText("ImmutableOpenMap should contain all keys ")
-                .appendValue(keys)
-                .appendText(", but key [")
-                .appendValue(missingKey)
-                .appendText("] is missing");
-        }
-    }
-
-}
diff --git a/test/framework/src/main/java/org/opensearch/test/hamcrest/OpenSearchAssertions.java b/test/framework/src/main/java/org/opensearch/test/hamcrest/OpenSearchAssertions.java
index 28afed1a50e59..3a39fd30f17dd 100644
--- a/test/framework/src/main/java/org/opensearch/test/hamcrest/OpenSearchAssertions.java
+++ b/test/framework/src/main/java/org/opensearch/test/hamcrest/OpenSearchAssertions.java
@@ -34,13 +34,11 @@
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TotalHits;
-import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
-import org.opensearch.action.ActionFuture;
+import org.opensearch.OpenSearchException;
 import org.opensearch.action.ActionRequestBuilder;
 import org.opensearch.action.admin.cluster.health.ClusterHealthRequestBuilder;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
-import org.opensearch.action.admin.indices.alias.exists.AliasesExistResponse;
 import org.opensearch.action.admin.indices.create.CreateIndexResponse;
 import org.opensearch.action.admin.indices.delete.DeleteIndexRequestBuilder;
 import org.opensearch.action.admin.indices.template.get.GetIndexTemplatesResponse;
@@ -50,7 +48,6 @@
 import org.opensearch.action.search.SearchRequestBuilder;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.ShardSearchFailure;
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.action.support.master.AcknowledgedRequestBuilder;
 import org.opensearch.action.support.master.AcknowledgedResponse;
@@ -59,15 +56,17 @@
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexTemplateMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.unit.TimeValue;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.ToXContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
-import org.opensearch.rest.RestStatus;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.suggest.Suggest;
 import org.opensearch.test.NotEqualMessageBuilder;
@@ -90,8 +89,6 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
-import static org.apache.lucene.tests.util.LuceneTestCase.expectThrows;
-import static org.apache.lucene.tests.util.LuceneTestCase.expectThrowsAnyOf;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -102,9 +99,10 @@
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.apache.lucene.tests.util.LuceneTestCase.expectThrows;
+import static org.apache.lucene.tests.util.LuceneTestCase.expectThrowsAnyOf;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -518,20 +516,6 @@ public static void assertIndexTemplateExists(GetIndexTemplatesResponse templates
         assertThat(templateNames, hasItem(name));
     }
 
-    /**
-     * Assert that aliases are missing
-     */
-    public static void assertAliasesMissing(AliasesExistResponse aliasesExistResponse) {
-        assertFalse("Aliases shouldn't exist", aliasesExistResponse.exists());
-    }
-
-    /**
-     * Assert that aliases exist
-     */
-    public static void assertAliasesExist(AliasesExistResponse aliasesExistResponse) {
-        assertTrue("Aliases should exist", aliasesExistResponse.exists());
-    }
-
     /*
      * matchers
      */
@@ -621,7 +605,7 @@ public static <E extends Throwable> void assertFutureThrows(ActionFuture<?> futu
      * Run future.actionGet() and check that it throws an exception of the right type, optionally checking the exception's rest status
      *
      * @param exceptionClass expected exception class
-     * @param status         {@link org.opensearch.rest.RestStatus} to check for. Can be null to disable the check
+     * @param status         {@link RestStatus} to check for. Can be null to disable the check
      * @param extraInfo      extra information to add to the failure message. Can be null.
      */
     public static <E extends Throwable> void assertFutureThrows(
@@ -702,12 +686,11 @@ public static void assertFileNotExists(Path file) {
 
     /**
      * Asserts that the provided {@link BytesReference}s created through
-     * {@link org.opensearch.common.xcontent.ToXContent#toXContent(XContentBuilder, ToXContent.Params)} hold the same content.
+     * {@link ToXContent#toXContent(XContentBuilder, ToXContent.Params)} hold the same content.
      * The comparison is done by parsing both into a map and comparing those two, so that keys ordering doesn't matter.
      * Also binary values (byte[]) are properly compared through arrays comparisons.
      */
-    public static void assertToXContentEquivalent(BytesReference expected, BytesReference actual, XContentType xContentType)
-        throws IOException {
+    public static void assertToXContentEquivalent(BytesReference expected, BytesReference actual, MediaType mediaType) throws IOException {
         // we tried comparing byte per byte, but that didn't fly for a couple of reasons:
         // 1) whenever anything goes through a map while parsing, ordering is not preserved, which is perfectly ok
         // 2) Jackson SMILE parser parses floats as double, which then get printed out as double (with double precision)
@@ -715,12 +698,12 @@ public static void assertToXContentEquivalent(BytesReference expected, BytesRefe
         Map<String, Object> actualMap = null;
         Map<String, Object> expectedMap = null;
         try (
-            XContentParser actualParser = xContentType.xContent()
+            XContentParser actualParser = mediaType.xContent()
                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, actual.streamInput())
         ) {
             actualMap = actualParser.map();
             try (
-                XContentParser expectedParser = xContentType.xContent()
+                XContentParser expectedParser = mediaType.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, expected.streamInput())
             ) {
                 expectedMap = expectedParser.map();
diff --git a/test/framework/src/main/java/org/opensearch/test/junit/listeners/ReproduceInfoPrinter.java b/test/framework/src/main/java/org/opensearch/test/junit/listeners/ReproduceInfoPrinter.java
index 668526d9d6d0d..e2d59773a76cb 100644
--- a/test/framework/src/main/java/org/opensearch/test/junit/listeners/ReproduceInfoPrinter.java
+++ b/test/framework/src/main/java/org/opensearch/test/junit/listeners/ReproduceInfoPrinter.java
@@ -32,12 +32,12 @@
 package org.opensearch.test.junit.listeners;
 
 import com.carrotsearch.randomizedtesting.ReproduceErrorMessageBuilder;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.opensearch.bootstrap.JavaVersion;
-import org.opensearch.common.Strings;
 import org.opensearch.common.SuppressForbidden;
+import org.opensearch.core.common.Strings;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.yaml.OpenSearchClientYamlSuiteTestCase;
@@ -192,7 +192,7 @@ private ReproduceErrorMessageBuilder appendESProperties() {
             }
             appendOpt("tests.locale", Locale.getDefault().toLanguageTag());
             appendOpt("tests.timezone", TimeZone.getDefault().getID());
-            appendOpt("runtime.java", Integer.toString(JavaVersion.current().getVersion().get(0)));
+            appendOpt("runtime.java", Integer.toString(Runtime.version().version().get(0)));
             appendOpt(OpenSearchTestCase.FIPS_SYSPROP, System.getProperty(OpenSearchTestCase.FIPS_SYSPROP));
             return this;
         }
@@ -200,7 +200,7 @@ private ReproduceErrorMessageBuilder appendESProperties() {
         public ReproduceErrorMessageBuilder appendClientYamlSuiteProperties() {
             return appendProperties(
                 OpenSearchClientYamlSuiteTestCase.REST_TESTS_SUITE,
-                OpenSearchClientYamlSuiteTestCase.REST_TESTS_BLACKLIST
+                OpenSearchClientYamlSuiteTestCase.REST_TESTS_DENYLIST
             );
         }
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/FakeRestChannel.java b/test/framework/src/main/java/org/opensearch/test/rest/FakeRestChannel.java
index a39fdd1eae096..9b3d72807ea25 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/FakeRestChannel.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/FakeRestChannel.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.test.rest;
 
+import org.opensearch.core.rest.RestStatus;
 import org.opensearch.rest.AbstractRestChannel;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.RestResponse;
-import org.opensearch.rest.RestStatus;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicInteger;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/FakeRestRequest.java b/test/framework/src/main/java/org/opensearch/test/rest/FakeRestRequest.java
index 9203f170d5368..e7810ae4c8f1c 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/FakeRestRequest.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/FakeRestRequest.java
@@ -32,16 +32,16 @@
 
 package org.opensearch.test.rest;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.http.HttpChannel;
 import org.opensearch.http.HttpRequest;
 import org.opensearch.http.HttpResponse;
 import org.opensearch.rest.RestRequest;
-import org.opensearch.rest.RestStatus;
 
 import java.net.InetSocketAddress;
 import java.util.Collections;
@@ -231,10 +231,10 @@ public Builder withParams(Map<String, String> params) {
             return this;
         }
 
-        public Builder withContent(BytesReference content, XContentType xContentType) {
+        public Builder withContent(BytesReference content, MediaType mediaType) {
             this.content = content;
-            if (xContentType != null) {
-                headers.put("Content-Type", Collections.singletonList(xContentType.mediaType()));
+            if (mediaType != null) {
+                headers.put("Content-Type", Collections.singletonList(mediaType.mediaType()));
             }
             return this;
         }
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
index 27369e79e5dee..dff6bb5c22bf5 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
@@ -41,7 +41,6 @@
 import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;
 import org.apache.http.ssl.SSLContexts;
 import org.apache.http.util.EntityUtils;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksAction;
@@ -55,23 +54,25 @@
 import org.opensearch.client.RestClientBuilder;
 import org.opensearch.client.WarningsHandler;
 import org.opensearch.common.CheckedRunnable;
-import org.opensearch.common.Strings;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.seqno.ReplicationTracker;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.snapshots.SnapshotState;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.rest.yaml.ObjectPath;
@@ -81,6 +82,7 @@
 import org.junit.Before;
 
 import javax.net.ssl.SSLContext;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -136,10 +138,10 @@ public abstract class OpenSearchRestTestCase extends OpenSearchTestCase {
      * Convert the entity from a {@link Response} into a map of maps.
      */
     public static Map<String, Object> entityAsMap(Response response) throws IOException {
-        XContentType xContentType = XContentType.fromMediaTypeOrFormat(response.getEntity().getContentType().getValue());
+        MediaType mediaType = MediaType.fromMediaType(response.getEntity().getContentType().getValue());
         // EMPTY and THROW are fine here because `.map` doesn't use named x content or deprecation
         try (
-            XContentParser parser = xContentType.xContent()
+            XContentParser parser = mediaType.xContent()
                 .createParser(
                     NamedXContentRegistry.EMPTY,
                     DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -154,10 +156,10 @@ public static Map<String, Object> entityAsMap(Response response) throws IOExcept
      * Convert the entity from a {@link Response} into a list of maps.
      */
     public static List<Object> entityAsList(Response response) throws IOException {
-        XContentType xContentType = XContentType.fromMediaTypeOrFormat(response.getEntity().getContentType().getValue());
+        MediaType mediaType = MediaType.fromMediaType(response.getEntity().getContentType().getValue());
         // EMPTY and THROW are fine here because `.map` doesn't use named x content or deprecation
         try (
-            XContentParser parser = xContentType.xContent()
+            XContentParser parser = mediaType.xContent()
                 .createParser(
                     NamedXContentRegistry.EMPTY,
                     DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
@@ -531,7 +533,8 @@ protected boolean waitForAllSnapshotsWiped() {
     private void wipeCluster() throws Exception {
 
         // Clean up SLM policies before trying to wipe snapshots so that no new ones get started by SLM after wiping
-        if (nodeVersions.first().onOrAfter(LegacyESVersion.V_7_4_0)) { // SLM was introduced in version 7.4
+        if (nodeVersions.first().onOrAfter(LegacyESVersion.V_7_4_0) && nodeVersions.first().before(Version.V_1_0_0)) { // SLM was introduced
+                                                                                                                       // in version 7.4
             if (preserveSLMPoliciesUponCompletion() == false) {
                 // Clean up SLM policies before trying to wipe snapshots so that no new ones get started by SLM after wiping
                 deleteAllSLMPolicies();
@@ -608,7 +611,7 @@ protected static void wipeAllIndices() throws IOException {
             deleteRequest.setOptions(allowSystemIndexAccessWarningOptions);
             final Response response = adminClient().performRequest(deleteRequest);
             try (InputStream is = response.getEntity().getContent()) {
-                assertTrue((boolean) XContentHelper.convertToMap(XContentType.JSON.xContent(), is, true).get("acknowledged"));
+                assertTrue((boolean) XContentHelper.convertToMap(MediaTypeRegistry.JSON.xContent(), is, true).get("acknowledged"));
             }
         } catch (ResponseException e) {
             // 404 here just means we had no indexes
@@ -625,7 +628,7 @@ protected static void wipeDataStreams() throws IOException {
             // We hit a version of ES that doesn't serialize DeleteDataStreamAction.Request#wildcardExpressionsOriginallySpecified field or
             // that doesn't support data streams so it's safe to ignore
             int statusCode = e.getResponse().getStatusLine().getStatusCode();
-            if (org.opensearch.common.collect.Set.of(404, 405, 500).contains(statusCode) == false) {
+            if (Set.of(404, 405, 500).contains(statusCode) == false) {
                 throw e;
             }
         }
@@ -651,6 +654,13 @@ protected static void wipeDataStreams() throws IOException {
                 for (Object snapshot : snapshots) {
                     Map<?, ?> snapshotInfo = (Map<?, ?>) snapshot;
                     String name = (String) snapshotInfo.get("snapshot");
+                    // Parallel test jobs create an issue with preserveSnapshotsUponCompletion set within subclasses.
+                    // Since the snapshots are shared within the cluster, another parallel run may delete all
+                    // snapshots in the repository.
+                    // For now we hack to prevent deletion of snapshots prefixed with "force_preserve"
+                    if (name.startsWith("force_preserve")) {
+                        continue;
+                    }
                     if (SnapshotState.valueOf((String) snapshotInfo.get("state")).completed() == false) {
                         inProgressSnapshots.computeIfAbsent(repoName, key -> new ArrayList<>()).add(snapshotInfo);
                     }
@@ -696,7 +706,7 @@ private void wipeClusterSettings() throws IOException {
 
         if (mustClear) {
             Request request = new Request("PUT", "/_cluster/settings");
-            request.setJsonEntity(Strings.toString(clearCommand));
+            request.setJsonEntity(clearCommand.toString());
             adminClient().performRequest(request);
         }
     }
@@ -958,7 +968,7 @@ protected static void createIndex(String name, Settings settings, String mapping
 
     protected static void createIndex(String name, Settings settings, String mapping, String aliases) throws IOException {
         Request request = new Request("PUT", "/" + name);
-        String entity = "{\"settings\": " + Strings.toString(settings);
+        String entity = "{\"settings\": " + Strings.toString(MediaTypeRegistry.JSON, settings);
         if (mapping != null) {
             entity += ",\"mappings\" : {" + mapping + "}";
         }
@@ -984,7 +994,7 @@ protected static void updateIndexSettings(String index, Settings.Builder setting
 
     private static void updateIndexSettings(String index, Settings settings) throws IOException {
         Request request = new Request("PUT", "/" + index + "/_settings");
-        request.setJsonEntity(Strings.toString(settings));
+        request.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, settings));
         client().performRequest(request);
     }
 
@@ -1027,7 +1037,7 @@ protected static Map<String, Object> getIndexSettings(String index) throws IOExc
         request.addParameter("flat_settings", "true");
         Response response = client().performRequest(request);
         try (InputStream is = response.getEntity().getContent()) {
-            return XContentHelper.convertToMap(XContentType.JSON.xContent(), is, true);
+            return XContentHelper.convertToMap(MediaTypeRegistry.JSON.xContent(), is, true);
         }
     }
 
@@ -1081,7 +1091,7 @@ protected static Map<String, Object> getAsMap(final String endpoint) throws IOEx
     }
 
     protected static Map<String, Object> responseAsMap(Response response) throws IOException {
-        XContentType entityContentType = XContentType.fromMediaTypeOrFormat(response.getEntity().getContentType().getValue());
+        MediaType entityContentType = MediaType.fromMediaType(response.getEntity().getContentType().getValue());
         Map<String, Object> responseEntity = XContentHelper.convertToMap(
             entityContentType.xContent(),
             response.getEntity().getContent(),
@@ -1094,7 +1104,7 @@ protected static Map<String, Object> responseAsMap(Response response) throws IOE
     protected static void registerRepository(String repository, String type, boolean verify, Settings settings) throws IOException {
         final Request request = new Request(HttpPut.METHOD_NAME, "_snapshot/" + repository);
         request.addParameter("verify", Boolean.toString(verify));
-        request.setJsonEntity(Strings.toString(new PutRepositoryRequest(repository).type(type).settings(settings)));
+        request.setJsonEntity(Strings.toString(MediaTypeRegistry.JSON, new PutRepositoryRequest(repository).type(type).settings(settings)));
 
         final Response response = client().performRequest(request);
         assertAcked("Failed to create repository [" + repository + "] of type [" + type + "]: " + response, response);
@@ -1257,7 +1267,7 @@ protected void syncedFlush(String indexName, boolean retryOnConflict) throws Exc
         final Builder options = RequestOptions.DEFAULT.toBuilder();
         // 8.0 kept in warning message for legacy purposes TODO: changge to 3.0
         final List<String> warningMessage = Arrays.asList(
-            "Synced flush is deprecated and will be removed in 8.0. Use flush at _/flush or /{index}/_flush instead."
+            "Synced flush is deprecated and will be removed in 3.0. Use flush at _/flush or /{index}/_flush instead."
         );
         final List<String> expectedWarnings = Arrays.asList(
             "Synced flush was removed and a normal flush was performed instead. This transition will be removed in a future version."
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/RestActionTestCase.java b/test/framework/src/main/java/org/opensearch/test/rest/RestActionTestCase.java
index 7d1e393a82bb7..dc13924195254 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/RestActionTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/RestActionTestCase.java
@@ -32,14 +32,15 @@
 
 package org.opensearch.test.rest;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRequest;
-import org.opensearch.action.ActionResponse;
 import org.opensearch.action.ActionType;
+import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.identity.IdentityService;
 import org.opensearch.rest.RestController;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.tasks.Task;
@@ -51,6 +52,7 @@
 import org.junit.Before;
 
 import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiFunction;
 
@@ -65,7 +67,15 @@ public abstract class RestActionTestCase extends OpenSearchTestCase {
     @Before
     public void setUpController() {
         verifyingClient = new VerifyingClient(this.getTestName());
-        controller = new RestController(Collections.emptySet(), null, verifyingClient, new NoneCircuitBreakerService(), new UsageService());
+        final IdentityService identityService = new IdentityService(Settings.EMPTY, List.of());
+        controller = new RestController(
+            Collections.emptySet(),
+            null,
+            verifyingClient,
+            new NoneCircuitBreakerService(),
+            new UsageService(),
+            identityService
+        );
     }
 
     @After
@@ -122,7 +132,7 @@ public void reset() {
          * @param verifier A function which is called in place of {@link #doExecute(ActionType, ActionRequest, ActionListener)}
          */
         public <Request extends ActionRequest, Response extends ActionResponse> void setExecuteVerifier(
-            BiFunction<ActionType<Response>, Request, Void> verifier
+            BiFunction<ActionType<Response>, Request, Response> verifier
         ) {
             executeVerifier.set(verifier);
         }
@@ -142,7 +152,7 @@ public <Request extends ActionRequest, Response extends ActionResponse> void doE
          * @param verifier A function which is called in place of {@link #executeLocally(ActionType, ActionRequest, TaskListener)}
          */
         public <Request extends ActionRequest, Response extends ActionResponse> void setExecuteLocallyVerifier(
-            BiFunction<ActionType<Response>, Request, Void> verifier
+            BiFunction<ActionType<Response>, Request, Response> verifier
         ) {
             executeLocallyVerifier.set(verifier);
         }
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcher.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcher.java
deleted file mode 100644
index 15510e368b1f5..0000000000000
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcher.java
+++ /dev/null
@@ -1,80 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.test.rest.yaml;
-
-import java.util.regex.Pattern;
-
-/**
- * Matches denylist patterns.
- *
- * Currently the following syntax is supported:
- *
- * <ul>
- *  <li>Exact matches, as in <code>cat.aliases/10_basic/Empty cluster</code></li>
- *  <li>Wildcard matches within the same segment of a path , as in <code>indices.get/10_basic/*allow_no_indices*</code>. This will
- *  match <code>indices.get/10_basic/allow_no_indices</code>, <code>indices.get/10_basic/allow_no_indices_at_all</code> but not
- *  <code>indices.get/10_basic/advanced/allow_no_indices</code> (contains an additional segment)</li>
- * </ul>
- *
- * Each denylist pattern is a suffix match on the path. Empty patterns are not allowed.
- */
-final class BlacklistedPathPatternMatcher {
-    private final Pattern pattern;
-
-    /**
-     * Constructs a new <code>DenylistedPathPatternMatcher</code> instance from the provided suffix pattern.
-     *
-     * @param p The suffix pattern. Must be a non-empty string.
-     */
-    BlacklistedPathPatternMatcher(String p) {
-        // guard against accidentally matching everything as an empty string lead to the pattern ".*" which matches everything
-        if (p == null || p.trim().isEmpty()) {
-            throw new IllegalArgumentException("Empty denylist patterns are not supported");
-        }
-        // very simple transformation from wildcard to a proper regex
-        String finalPattern = p.replaceAll("\\*", "[^/]*") // support wildcard matches (within a single path segment)
-            .replaceAll("\\\\,", ",");  // restore previously escaped ',' in paths.
-
-        // suffix match
-        pattern = Pattern.compile(".*" + finalPattern);
-    }
-
-    /**
-     * Checks whether the provided path matches the suffix pattern, i.e. "/foo/bar" will match the pattern "bar".
-     *
-     * @param path The path to match. Must not be null.
-     * @return true iff this path is a suffix match.
-     */
-    public boolean isSuffixMatch(String path) {
-        return pattern.matcher(path).matches();
-    }
-}
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlDocsTestClient.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlDocsTestClient.java
index d57fa7ff82f07..cd5f1fe168b12 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlDocsTestClient.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlDocsTestClient.java
@@ -62,10 +62,10 @@ public ClientYamlDocsTestClient(
         final RestClient restClient,
         final List<HttpHost> hosts,
         final Version esVersion,
-        final Version masterVersion,
+        final Version clusterManagerVersion,
         final CheckedSupplier<RestClientBuilder, IOException> clientBuilderWithSniffedNodes
     ) {
-        super(restSpec, restClient, hosts, esVersion, masterVersion, clientBuilderWithSniffedNodes);
+        super(restSpec, restClient, hosts, esVersion, clusterManagerVersion, clientBuilderWithSniffedNodes);
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestCandidate.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestCandidate.java
index e4fa8bedaa7f2..6589e7597b9ac 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestCandidate.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestCandidate.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.test.rest.yaml;
 
+import org.opensearch.test.rest.yaml.section.ClientYamlTestSection;
 import org.opensearch.test.rest.yaml.section.ClientYamlTestSuite;
 import org.opensearch.test.rest.yaml.section.SetupSection;
 import org.opensearch.test.rest.yaml.section.TeardownSection;
-import org.opensearch.test.rest.yaml.section.ClientYamlTestSection;
 
 /**
  * Wraps {@link ClientYamlTestSection}s ready to be run. Each test section is associated to its {@link ClientYamlTestSuite}.
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestClient.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestClient.java
index 7a31c73d24305..00380b91bfa15 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestClient.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestClient.java
@@ -32,6 +32,7 @@
 package org.opensearch.test.rest.yaml;
 
 import com.carrotsearch.randomizedtesting.RandomizedTest;
+
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
 import org.apache.http.client.methods.HttpGet;
@@ -57,6 +58,8 @@
 import java.io.UncheckedIOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
@@ -78,7 +81,7 @@ public class ClientYamlTestClient implements Closeable {
     private final ClientYamlSuiteRestSpec restSpec;
     private final Map<NodeSelector, RestClient> restClients = new HashMap<>();
     private final Version esVersion;
-    private final Version masterVersion;
+    private final Version clusterManagerVersion;
     private final CheckedSupplier<RestClientBuilder, IOException> clientBuilderWithSniffedNodes;
 
     ClientYamlTestClient(
@@ -86,14 +89,14 @@ public class ClientYamlTestClient implements Closeable {
         final RestClient restClient,
         final List<HttpHost> hosts,
         final Version esVersion,
-        final Version masterVersion,
+        final Version clusterManagerVersion,
         final CheckedSupplier<RestClientBuilder, IOException> clientBuilderWithSniffedNodes
     ) {
         assert hosts.size() > 0;
         this.restSpec = restSpec;
         this.restClients.put(NodeSelector.ANY, restClient);
         this.esVersion = esVersion;
-        this.masterVersion = masterVersion;
+        this.clusterManagerVersion = clusterManagerVersion;
         this.clientBuilderWithSniffedNodes = clientBuilderWithSniffedNodes;
     }
 
@@ -101,8 +104,14 @@ public Version getEsVersion() {
         return esVersion;
     }
 
+    public Version getClusterManagerVersion() {
+        return clusterManagerVersion;
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #getClusterManagerVersion()} */
+    @Deprecated
     public Version getMasterVersion() {
-        return masterVersion;
+        return getClusterManagerVersion();
     }
 
     /**
@@ -184,7 +193,7 @@ public ClientYamlTestResponse callApi(
             }
             String contentType = entity.getContentType().getValue();
             // randomly test the GET with source param instead of GET/POST with body
-            if (sendBodyAsSourceParam(supportedMethods, contentType, entity.getContentLength())) {
+            if (sendBodyAsSourceParam(supportedMethods, contentType, entity)) {
                 logger.debug("sending the request body as source param with GET method");
                 queryStringParams.put("source", EntityUtils.toString(entity));
                 queryStringParams.put("source_content_type", contentType);
@@ -241,11 +250,12 @@ protected static void setOptions(Request request, Map<String, String> headers) {
         request.setOptions(options);
     }
 
-    private static boolean sendBodyAsSourceParam(List<String> supportedMethods, String contentType, long contentLength) {
+    private static boolean sendBodyAsSourceParam(List<String> supportedMethods, String contentType, HttpEntity entity) throws IOException {
         if (false == supportedMethods.contains(HttpGet.METHOD_NAME)) {
             // The API doesn't claim to support GET anyway
             return false;
         }
+        long contentLength = entity.getContentLength();
         if (contentLength < 0) {
             // Negative length means "unknown" or "huge" in this case. Either way we can't send it as a parameter
             return false;
@@ -259,7 +269,18 @@ private static boolean sendBodyAsSourceParam(List<String> supportedMethods, Stri
             // We can only encode JSON or YAML this way.
             return false;
         }
-        return RandomizedTest.rarely();
+
+        return RandomizedTest.rarely() && isUrlEncodedLengthUnderLimit(entity);
+    }
+
+    /*
+     * There is a limit of 4096 bytes for the HTTP line, otherwise there will be too_long_http_line_exception.
+     * We check if the length of the url-encoded source parameter is less than 3000, leaving remaining for
+     * url and other params.
+     */
+    private static boolean isUrlEncodedLengthUnderLimit(HttpEntity entity) throws IOException {
+        String encoded = URLEncoder.encode(EntityUtils.toString(entity), StandardCharsets.UTF_8);
+        return encoded.length() < 3000;
     }
 
     private ClientYamlSuiteRestApi restApi(String apiName) {
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestExecutionContext.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestExecutionContext.java
index 4c3a1ec863d31..bb13055435c43 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestExecutionContext.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestExecutionContext.java
@@ -41,10 +41,11 @@
 import org.apache.lucene.util.BytesRef;
 import org.opensearch.Version;
 import org.opensearch.client.NodeSelector;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -63,7 +64,7 @@ public class ClientYamlTestExecutionContext {
 
     private static final Logger logger = LogManager.getLogger(ClientYamlTestExecutionContext.class);
 
-    private static final XContentType[] STREAMING_CONTENT_TYPES = new XContentType[] { XContentType.JSON, XContentType.SMILE };
+    private static final MediaType[] STREAMING_CONTENT_TYPES = new MediaType[] { MediaTypeRegistry.JSON, XContentType.SMILE };
 
     private final Stash stash = new Stash();
     private final ClientYamlTestClient clientYamlTestClient;
@@ -138,20 +139,20 @@ private HttpEntity createEntity(List<Map<String, Object>> bodies, Map<String, St
             return null;
         }
         if (bodies.size() == 1) {
-            XContentType xContentType = getContentType(headers, XContentType.values());
-            BytesRef bytesRef = bodyAsBytesRef(bodies.get(0), xContentType);
+            MediaType mediaType = getContentType(headers, XContentType.values());
+            BytesRef bytesRef = bodyAsBytesRef(bodies.get(0), mediaType);
             return new ByteArrayEntity(
                 bytesRef.bytes,
                 bytesRef.offset,
                 bytesRef.length,
-                ContentType.create(xContentType.mediaTypeWithoutParameters(), StandardCharsets.UTF_8)
+                ContentType.create(mediaType.mediaTypeWithoutParameters(), StandardCharsets.UTF_8)
             );
         } else {
-            XContentType xContentType = getContentType(headers, STREAMING_CONTENT_TYPES);
+            MediaType mediaType = getContentType(headers, STREAMING_CONTENT_TYPES);
             List<BytesRef> bytesRefList = new ArrayList<>(bodies.size());
             int totalBytesLength = 0;
             for (Map<String, Object> body : bodies) {
-                BytesRef bytesRef = bodyAsBytesRef(body, xContentType);
+                BytesRef bytesRef = bodyAsBytesRef(body, mediaType);
                 bytesRefList.add(bytesRef);
                 totalBytesLength += bytesRef.length - bytesRef.offset + 1;
             }
@@ -161,30 +162,30 @@ private HttpEntity createEntity(List<Map<String, Object>> bodies, Map<String, St
                 for (int i = bytesRef.offset; i < bytesRef.length; i++) {
                     bytes[position++] = bytesRef.bytes[i];
                 }
-                bytes[position++] = xContentType.xContent().streamSeparator();
+                bytes[position++] = mediaType.xContent().streamSeparator();
             }
-            return new ByteArrayEntity(bytes, ContentType.create(xContentType.mediaTypeWithoutParameters(), StandardCharsets.UTF_8));
+            return new ByteArrayEntity(bytes, ContentType.create(mediaType.mediaTypeWithoutParameters(), StandardCharsets.UTF_8));
         }
     }
 
-    private XContentType getContentType(Map<String, String> headers, XContentType[] supportedContentTypes) {
-        XContentType xContentType = null;
+    private MediaType getContentType(Map<String, String> headers, MediaType[] supportedContentTypes) {
+        MediaType mediaType = null;
         String contentType = headers.get("Content-Type");
         if (contentType != null) {
-            xContentType = XContentType.fromMediaType(contentType);
+            mediaType = MediaType.fromMediaType(contentType);
         }
-        if (xContentType != null) {
-            return xContentType;
+        if (mediaType != null) {
+            return mediaType;
         }
         if (randomizeContentType) {
             return RandomizedTest.randomFrom(supportedContentTypes);
         }
-        return XContentType.JSON;
+        return MediaTypeRegistry.JSON;
     }
 
-    private BytesRef bodyAsBytesRef(Map<String, Object> bodyAsMap, XContentType xContentType) throws IOException {
+    private BytesRef bodyAsBytesRef(Map<String, Object> bodyAsMap, MediaType mediaType) throws IOException {
         Map<String, Object> finalBodyAsMap = stash.replaceStashedValues(bodyAsMap);
-        try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType)) {
+        try (XContentBuilder builder = MediaTypeRegistry.contentBuilder(mediaType)) {
             return BytesReference.bytes(builder.map(finalBodyAsMap)).toBytesRef();
         }
     }
@@ -227,8 +228,14 @@ public Version esVersion() {
         return clientYamlTestClient.getEsVersion();
     }
 
+    public Version clusterManagerVersion() {
+        return clientYamlTestClient.getClusterManagerVersion();
+    }
+
+    /** @deprecated As of 2.2, because supporting inclusive language, replaced by {@link #clusterManagerVersion()} */
+    @Deprecated
     public Version masterVersion() {
-        return clientYamlTestClient.getMasterVersion();
+        return clusterManagerVersion();
     }
 
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestResponse.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestResponse.java
index 4e8799b9a618e..91cd1bffebf7d 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestResponse.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ClientYamlTestResponse.java
@@ -35,14 +35,15 @@
 import org.apache.http.client.methods.HttpHead;
 import org.apache.http.util.EntityUtils;
 import org.opensearch.client.Response;
-import org.opensearch.common.Strings;
-import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -58,7 +59,7 @@ public class ClientYamlTestResponse {
 
     private final Response response;
     private final byte[] body;
-    private final XContentType bodyContentType;
+    private final MediaType bodyContentType;
     private ObjectPath parsedResponse;
     private String bodyAsString;
 
@@ -66,7 +67,7 @@ public ClientYamlTestResponse(Response response) throws IOException {
         this.response = response;
         if (response.getEntity() != null) {
             String contentType = response.getHeader("Content-Type");
-            this.bodyContentType = XContentType.fromMediaTypeOrFormat(contentType);
+            this.bodyContentType = MediaType.fromMediaType(contentType);
             try {
                 byte[] bytes = EntityUtils.toByteArray(response.getEntity());
                 // skip parsing if we got text back (e.g. if we called _cat apis)
@@ -124,7 +125,7 @@ public Object getBody() throws IOException {
     public String getBodyAsString() {
         if (bodyAsString == null && body != null) {
             // content-type null means that text was returned
-            if (bodyContentType == null || bodyContentType == XContentType.JSON || bodyContentType == XContentType.YAML) {
+            if (bodyContentType == null || bodyContentType == MediaTypeRegistry.JSON || bodyContentType == XContentType.YAML) {
                 bodyAsString = new String(body, StandardCharsets.UTF_8);
             } else {
                 // if the body is in a binary format and gets requested as a string (e.g. to log a test failure), we convert it to json
@@ -135,7 +136,7 @@ public String getBodyAsString() {
                     ) {
                         jsonBuilder.copyCurrentStructure(parser);
                     }
-                    bodyAsString = Strings.toString(jsonBuilder);
+                    bodyAsString = jsonBuilder.toString();
                 } catch (IOException e) {
                     throw new UncheckedIOException("unable to convert response body to a string format", e);
                 }
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcher.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcher.java
new file mode 100644
index 0000000000000..eeaa76b6ca1b3
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcher.java
@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.test.rest.yaml;
+
+import java.util.regex.Pattern;
+
+/**
+ * Matches denylist patterns.
+ *
+ * Currently the following syntax is supported:
+ *
+ * <ul>
+ *  <li>Exact matches, as in <code>cat.aliases/10_basic/Empty cluster</code></li>
+ *  <li>Wildcard matches within the same segment of a path , as in <code>indices.get/10_basic/*allow_no_indices*</code>. This will
+ *  match <code>indices.get/10_basic/allow_no_indices</code>, <code>indices.get/10_basic/allow_no_indices_at_all</code> but not
+ *  <code>indices.get/10_basic/advanced/allow_no_indices</code> (contains an additional segment)</li>
+ * </ul>
+ *
+ * Each denylist pattern is a suffix match on the path. Empty patterns are not allowed.
+ */
+final class DenylistedPathPatternMatcher {
+    private final Pattern pattern;
+
+    /**
+     * Constructs a new <code>DenylistedPathPatternMatcher</code> instance from the provided suffix pattern.
+     *
+     * @param p The suffix pattern. Must be a non-empty string.
+     */
+    DenylistedPathPatternMatcher(String p) {
+        // guard against accidentally matching everything as an empty string lead to the pattern ".*" which matches everything
+        if (p == null || p.trim().isEmpty()) {
+            throw new IllegalArgumentException("Empty denylist patterns are not supported");
+        }
+        // very simple transformation from wildcard to a proper regex
+        String finalPattern = p.replaceAll("\\*", "[^/]*") // support wildcard matches (within a single path segment)
+            .replaceAll("\\\\,", ",");  // restore previously escaped ',' in paths.
+
+        // suffix match
+        pattern = Pattern.compile(".*" + finalPattern);
+    }
+
+    /**
+     * Checks whether the provided path matches the suffix pattern, i.e. "/foo/bar" will match the pattern "bar".
+     *
+     * @param path The path to match. Must not be null.
+     * @return true iff this path is a suffix match.
+     */
+    public boolean isSuffixMatch(String path) {
+        return pattern.matcher(path).matches();
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/Features.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/Features.java
index 6e59e35dcb0b4..10fb1e52259a9 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/Features.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/Features.java
@@ -32,8 +32,6 @@
 
 package org.opensearch.test.rest.yaml;
 
-import org.opensearch.bootstrap.JavaVersion;
-
 import java.util.Arrays;
 import java.util.List;
 
@@ -86,7 +84,7 @@ public static boolean areAllSupported(List<String> features) {
     }
 
     private static boolean isSupported(String feature) {
-        if (feature.equals(SPI_ON_CLASSPATH_SINCE_JDK_9) && JavaVersion.current().compareTo(JavaVersion.parse("9")) >= 0) {
+        if (feature.equals(SPI_ON_CLASSPATH_SINCE_JDK_9)) {
             return true;
         }
         return SUPPORTED.contains(feature);
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ObjectPath.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ObjectPath.java
index 0ff1b36d1f5ae..1b401cdd0a8f5 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/ObjectPath.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/ObjectPath.java
@@ -33,14 +33,14 @@
 
 import org.apache.http.util.EntityUtils;
 import org.opensearch.client.Response;
-import org.opensearch.common.bytes.BytesArray;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContent;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesArray;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -57,8 +57,8 @@ public class ObjectPath {
     public static ObjectPath createFromResponse(Response response) throws IOException {
         byte[] bytes = EntityUtils.toByteArray(response.getEntity());
         String contentType = response.getHeader("Content-Type");
-        XContentType xContentType = XContentType.fromMediaTypeOrFormat(contentType);
-        return ObjectPath.createFromXContent(xContentType.xContent(), new BytesArray(bytes));
+        MediaType mediaType = MediaType.fromMediaType(contentType);
+        return ObjectPath.createFromXContent(mediaType.xContent(), new BytesArray(bytes));
     }
 
     public static ObjectPath createFromXContent(XContent xContent, BytesReference input) throws IOException {
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCase.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCase.java
index 5a404ccd4b9fc..03eb7292c5431 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCase.java
@@ -34,6 +34,7 @@
 
 import com.carrotsearch.randomizedtesting.RandomizedTest;
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
+
 import org.apache.http.HttpHost;
 import org.apache.lucene.tests.util.TimeUnits;
 import org.opensearch.Version;
@@ -45,11 +46,12 @@
 import org.opensearch.client.RestClientBuilder;
 import org.opensearch.client.WarningsHandler;
 import org.opensearch.client.sniff.OpenSearchNodesSniffer;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.PathUtils;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.opensearch.test.rest.yaml.restspec.ClientYamlSuiteRestApi;
 import org.opensearch.test.rest.yaml.restspec.ClientYamlSuiteRestSpec;
@@ -89,14 +91,14 @@ public abstract class OpenSearchClientYamlSuiteTestCase extends OpenSearchRestTe
     public static final String REST_TESTS_SUITE = "tests.rest.suite";
     /**
      * Property that allows to denylist some of the REST tests based on a comma separated list of globs
-     * e.g. "-Dtests.rest.blacklist=get/10_basic/*"
+     * e.g. "-Dtests.rest.denylist=get/10_basic/*"
      */
-    public static final String REST_TESTS_BLACKLIST = "tests.rest.blacklist";
+    public static final String REST_TESTS_DENYLIST = "tests.rest.denylist";
     /**
-     * We use tests.rest.blacklist in build files to denylist tests; this property enables a user to add additional denylisted tests on
+     * We use tests.rest.denylist in build files to denylist tests; this property enables a user to add additional denylisted tests on
      * top of the tests denylisted in the build.
      */
-    public static final String REST_TESTS_BLACKLIST_ADDITIONS = "tests.rest.blacklist_additions";
+    public static final String REST_TESTS_DENYLIST_ADDITIONS = "tests.rest.denylist_additions";
     /**
      * Property that allows to control whether spec validation is enabled or not (default true).
      */
@@ -116,7 +118,7 @@ public abstract class OpenSearchClientYamlSuiteTestCase extends OpenSearchRestTe
      */
     private static final String PATHS_SEPARATOR = "(?<!\\\\),";
 
-    private static List<BlacklistedPathPatternMatcher> denylistPathMatchers;
+    private static List<DenylistedPathPatternMatcher> denylistPathMatchers;
     private static ClientYamlTestExecutionContext restTestExecutionContext;
     private static ClientYamlTestExecutionContext adminExecutionContext;
     private static ClientYamlTestClient clientYamlTestClient;
@@ -144,24 +146,24 @@ public void initAndResetContext() throws Exception {
             final List<HttpHost> hosts = getClusterHosts();
             Tuple<Version, Version> versionVersionTuple = readVersionsFromCatNodes(adminClient());
             final Version minVersion = versionVersionTuple.v1();
-            final Version masterVersion = versionVersionTuple.v2();
+            final Version clusterManagerVersion = versionVersionTuple.v2();
             logger.info(
-                "initializing client, minimum OpenSearch version [{}], master version, [{}], hosts {}",
+                "initializing client, minimum OpenSearch version [{}], cluster-manager version, [{}], hosts {}",
                 minVersion,
-                masterVersion,
+                clusterManagerVersion,
                 hosts
             );
-            clientYamlTestClient = initClientYamlTestClient(restSpec, client(), hosts, minVersion, masterVersion);
+            clientYamlTestClient = initClientYamlTestClient(restSpec, client(), hosts, minVersion, clusterManagerVersion);
             restTestExecutionContext = new ClientYamlTestExecutionContext(clientYamlTestClient, randomizeContentType());
             adminExecutionContext = new ClientYamlTestExecutionContext(clientYamlTestClient, false);
-            final String[] denylist = resolvePathsProperty(REST_TESTS_BLACKLIST, null);
+            final String[] denylist = resolvePathsProperty(REST_TESTS_DENYLIST, null);
             denylistPathMatchers = new ArrayList<>();
             for (final String entry : denylist) {
-                denylistPathMatchers.add(new BlacklistedPathPatternMatcher(entry));
+                denylistPathMatchers.add(new DenylistedPathPatternMatcher(entry));
             }
-            final String[] denylistAdditions = resolvePathsProperty(REST_TESTS_BLACKLIST_ADDITIONS, null);
+            final String[] denylistAdditions = resolvePathsProperty(REST_TESTS_DENYLIST_ADDITIONS, null);
             for (final String entry : denylistAdditions) {
-                denylistPathMatchers.add(new BlacklistedPathPatternMatcher(entry));
+                denylistPathMatchers.add(new DenylistedPathPatternMatcher(entry));
             }
         }
         assert restTestExecutionContext != null;
@@ -179,9 +181,16 @@ protected ClientYamlTestClient initClientYamlTestClient(
         final RestClient restClient,
         final List<HttpHost> hosts,
         final Version esVersion,
-        final Version masterVersion
+        final Version clusterManagerVersion
     ) {
-        return new ClientYamlTestClient(restSpec, restClient, hosts, esVersion, masterVersion, this::getClientBuilderWithSniffedHosts);
+        return new ClientYamlTestClient(
+            restSpec,
+            restClient,
+            hosts,
+            esVersion,
+            clusterManagerVersion,
+            this::getClientBuilderWithSniffedHosts
+        );
     }
 
     @AfterClass
@@ -330,28 +339,28 @@ private static void validateSpec(ClientYamlSuiteRestSpec restSpec) {
      * Detect minimal node version and master node version of cluster using REST Client.
      *
      * @param restClient REST client used to discover cluster nodes
-     * @return {@link Tuple} of [minimal node version, master node version]
+     * @return {@link Tuple} of [minimal node version, cluster-manager node version]
      * @throws IOException When _cat API output parsing fails
      */
     private Tuple<Version, Version> readVersionsFromCatNodes(RestClient restClient) throws IOException {
         // we simply go to the _cat/nodes API and parse all versions in the cluster
         final Request request = new Request("GET", "/_cat/nodes");
         request.addParameter("h", "version,master");
-        request.setOptions(getCatNodesVersionMasterRequestOptions());
+        request.setOptions(getCatNodesVersionClusterManagerRequestOptions());
         Response response = restClient.performRequest(request);
         ClientYamlTestResponse restTestResponse = new ClientYamlTestResponse(response);
         String nodesCatResponse = restTestResponse.getBodyAsString();
         String[] split = nodesCatResponse.split("\n");
         Version version = null;
-        Version masterVersion = null;
+        Version clusterManagerVersion = null;
         for (String perNode : split) {
-            final String[] versionAndMaster = perNode.split("\\s+");
-            assert versionAndMaster.length == 2 : "invalid line: " + perNode + " length: " + versionAndMaster.length;
-            final Version currentVersion = Version.fromString(versionAndMaster[0]);
-            final boolean master = versionAndMaster[1].trim().equals("*");
-            if (master) {
-                assert masterVersion == null;
-                masterVersion = currentVersion;
+            final String[] versionAndClusterManager = perNode.split("\\s+");
+            assert versionAndClusterManager.length == 2 : "invalid line: " + perNode + " length: " + versionAndClusterManager.length;
+            final Version currentVersion = Version.fromString(versionAndClusterManager[0]);
+            final boolean clusterManager = versionAndClusterManager[1].trim().equals("*");
+            if (clusterManager) {
+                assert clusterManagerVersion == null;
+                clusterManagerVersion = currentVersion;
             }
             if (version == null) {
                 version = currentVersion;
@@ -359,21 +368,18 @@ private Tuple<Version, Version> readVersionsFromCatNodes(RestClient restClient)
                 version = currentVersion;
             }
         }
-        return new Tuple<>(version, masterVersion);
+        return new Tuple<>(version, clusterManagerVersion);
     }
 
-    protected RequestOptions getCatNodesVersionMasterRequestOptions() {
+    protected RequestOptions getCatNodesVersionClusterManagerRequestOptions() {
         return RequestOptions.DEFAULT;
     }
 
     public void test() throws IOException {
         // skip test if it matches one of the denylist globs
-        for (BlacklistedPathPatternMatcher denylistedPathMatcher : denylistPathMatchers) {
+        for (DenylistedPathPatternMatcher denylistedPathMatcher : denylistPathMatchers) {
             String testPath = testCandidate.getSuitePath() + "/" + testCandidate.getTestSection().getName();
-            assumeFalse(
-                "[" + testCandidate.getTestPath() + "] skipped, reason: blacklisted",
-                denylistedPathMatcher.isSuffixMatch(testPath)
-            );
+            assumeFalse("[" + testCandidate.getTestPath() + "] skipped, reason: denylisted", denylistedPathMatcher.isSuffixMatch(testPath));
         }
 
         // skip test if the whole suite (yaml file) is disabled
@@ -445,7 +451,7 @@ private void executeSection(ExecutableSection executableSection) {
             // Dump the stash on failure. Instead of dumping it in true json we escape `\n`s so stack traces are easier to read
             logger.info(
                 "Stash dump on test failure [{}]",
-                Strings.toString(restTestExecutionContext.stash(), true, true)
+                Strings.toString(MediaTypeRegistry.JSON, restTestExecutionContext.stash(), true, true)
                     .replace("\\n", "\n")
                     .replace("\\r", "\r")
                     .replace("\\t", "\t")
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/Stash.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/Stash.java
index 056f3b0b6cc04..4f5dd35602256 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/Stash.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/Stash.java
@@ -34,9 +34,9 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.ToXContentFragment;
-import org.opensearch.common.xcontent.XContentBuilder;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.ToXContentFragment;
+import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParser.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParser.java
index 97515472650c5..d8a9719fcd9c8 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParser.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParser.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.test.rest.yaml.restspec;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.ObjectParser;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.ObjectParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.HashSet;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestSpec.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestSpec.java
index a4964b1a142da..7de8e49f1526d 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestSpec.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestSpec.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ApiCallSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ApiCallSection.java
index 335dcc3c6d28d..9e6b043181c8c 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ApiCallSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ApiCallSection.java
@@ -31,14 +31,14 @@
 
 package org.opensearch.test.rest.yaml.section;
 
+import org.opensearch.client.NodeSelector;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-import org.opensearch.client.NodeSelector;
-
 import static java.util.Collections.unmodifiableMap;
 
 /**
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/Assertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/Assertion.java
index 14568753bf5d6..b9cbaacdf8873 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/Assertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/Assertion.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentLocation;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSection.java
index ebc945864ee6f..6902e011f2580 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSection.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuite.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuite.java
index 8e4218b2021ea..2e7c57a62d1a3 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuite.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuite.java
@@ -32,12 +32,12 @@
 package org.opensearch.test.rest.yaml.section;
 
 import org.opensearch.client.NodeSelector;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ContainsAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ContainsAssertion.java
index 0e81150106ec0..8012b90b1b04f 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ContainsAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ContainsAssertion.java
@@ -34,8 +34,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/DoSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/DoSection.java
index 6f29207e2a823..429ad448f0655 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/DoSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/DoSection.java
@@ -39,20 +39,20 @@
 import org.opensearch.client.HasAttributeNodeSelector;
 import org.opensearch.client.Node;
 import org.opensearch.client.NodeSelector;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.logging.HeaderWarning;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParseException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParseException;
+import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.test.hamcrest.RegexMatcher;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 import org.opensearch.test.rest.yaml.ClientYamlTestResponse;
 import org.opensearch.test.rest.yaml.ClientYamlTestResponseException;
-import org.opensearch.test.hamcrest.RegexMatcher;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -321,7 +321,7 @@ public void execute(ClientYamlTestExecutionContext executionContext) throws IOEx
                 }
                 fail(formatStatusCodeMessage(response, catchStatusCode));
             }
-            checkWarningHeaders(response.getWarningHeaders(), executionContext.masterVersion());
+            checkWarningHeaders(response.getWarningHeaders(), executionContext.clusterManagerVersion());
         } catch (ClientYamlTestResponseException e) {
             ClientYamlTestResponse restTestResponse = e.getRestTestResponse();
             if (!Strings.hasLength(catchParam)) {
@@ -353,7 +353,7 @@ public void execute(ClientYamlTestExecutionContext executionContext) throws IOEx
     /**
      * Check that the response contains only the warning headers that we expect.
      */
-    void checkWarningHeaders(final List<String> warningHeaders, final Version masterVersion) {
+    void checkWarningHeaders(final List<String> warningHeaders, final Version clusterManagerVersion) {
         final List<String> unexpected = new ArrayList<>();
         final List<String> unmatched = new ArrayList<>();
         final List<String> missing = new ArrayList<>();
@@ -367,7 +367,7 @@ void checkWarningHeaders(final List<String> warningHeaders, final Version master
             final boolean matches = matcher.matches();
             if (matches) {
                 final String message = HeaderWarning.extractWarningValueFromWarningHeader(header, true);
-                if (masterVersion.before(LegacyESVersion.V_7_0_0)
+                if (clusterManagerVersion.before(LegacyESVersion.V_7_0_0)
                     && message.equals(
                         "the default number of shards will change from [5] to [1] in 7.0.0; "
                             + "if you wish to continue using the default of [5] shards, "
@@ -375,7 +375,7 @@ void checkWarningHeaders(final List<String> warningHeaders, final Version master
                     )) {
                     /*
                      * This warning header will come back in the vast majority of our tests that create an index when running against an
-                     * older master. Rather than rewrite our tests to assert this warning header, we assume that it is expected.
+                     * older cluster-manager. Rather than rewrite our tests to assert this warning header, we assume that it is expected.
                      */
                     continue;
                 }
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ExecutableSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ExecutableSection.java
index 0ae1712c14345..0e452e8cde9d0 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ExecutableSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ExecutableSection.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParseField;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.ParseField;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanAssertion.java
index df6fb7495b53a..4c2e70f37a33c 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanAssertion.java
@@ -34,8 +34,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanEqualToAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanEqualToAssertion.java
index fcf5c7199e4b4..2132c2ebab51c 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanEqualToAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/GreaterThanEqualToAssertion.java
@@ -35,8 +35,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsFalseAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsFalseAssertion.java
index 7a195bb367e3f..6cfbbfc5df8d5 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsFalseAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsFalseAssertion.java
@@ -33,8 +33,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsTrueAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsTrueAssertion.java
index b14f1838d301f..e746542d89126 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsTrueAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/IsTrueAssertion.java
@@ -33,8 +33,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LengthAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LengthAssertion.java
index 480e620afe1f9..fd7d8d632cc1e 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LengthAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LengthAssertion.java
@@ -34,8 +34,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.List;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanAssertion.java
index c0a87ddada21c..263e0c8fb9c42 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanAssertion.java
@@ -34,8 +34,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanOrEqualToAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanOrEqualToAssertion.java
index 2931c5a4318da..f0e7d0c01b8f0 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanOrEqualToAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/LessThanOrEqualToAssertion.java
@@ -35,8 +35,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/MatchAssertion.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/MatchAssertion.java
index 6558f029143a1..a97e3e4cb77ed 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/MatchAssertion.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/MatchAssertion.java
@@ -34,8 +34,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.NotEqualMessageBuilder;
 import org.opensearch.test.hamcrest.RegexMatcher;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ParserUtils.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ParserUtils.java
index 4aa47af62552c..c18a6ca6e3336 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ParserUtils.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/ParserUtils.java
@@ -33,7 +33,7 @@
 package org.opensearch.test.rest.yaml.section;
 
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetSection.java
index 057dbe7d728cf..a561a53119a96 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetSection.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetupSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetupSection.java
index d12130011ae82..a5e65faa197ef 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetupSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SetupSection.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SkipSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SkipSection.java
index d988774c9b04e..cf0d6dc826ffb 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SkipSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/SkipSection.java
@@ -32,9 +32,9 @@
 package org.opensearch.test.rest.yaml.section;
 
 import org.opensearch.Version;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.rest.yaml.Features;
 
@@ -117,10 +117,10 @@ public static SkipSection parse(XContentParser parser) throws IOException {
 
         parser.nextToken();
 
-        if (!Strings.hasLength(version) && features.isEmpty()) {
+        if (Strings.hasLength(version) == false && features.isEmpty() == true) {
             throw new ParsingException(parser.getTokenLocation(), "version or features is mandatory within skip section");
         }
-        if (Strings.hasLength(version) && !Strings.hasLength(reason)) {
+        if (Strings.hasLength(version) == true && Strings.hasLength(reason) == false) {
             throw new ParsingException(parser.getTokenLocation(), "reason is mandatory within skip version section");
         }
         return new SkipSection(version, features, reason);
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TeardownSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TeardownSection.java
index 38b33c2c9f8cb..88a1f85f7c920 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TeardownSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TeardownSection.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TransformAndSetSection.java b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TransformAndSetSection.java
index a1f7ff260f647..f2ecbe4c19806 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TransformAndSetSection.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/yaml/section/TransformAndSetSection.java
@@ -32,9 +32,9 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 
 import java.io.IOException;
diff --git a/test/framework/src/main/java/org/opensearch/test/store/MockFSDirectoryFactory.java b/test/framework/src/main/java/org/opensearch/test/store/MockFSDirectoryFactory.java
index 47952af1cd06c..9c42ea2672601 100644
--- a/test/framework/src/main/java/org/opensearch/test/store/MockFSDirectoryFactory.java
+++ b/test/framework/src/main/java/org/opensearch/test/store/MockFSDirectoryFactory.java
@@ -33,11 +33,12 @@
 package org.opensearch.test.store;
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
+
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.index.CheckIndex;
-import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.LockObtainFailedException;
+import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.tests.store.MockDirectoryWrapper;
 import org.apache.lucene.tests.util.LuceneTestCase;
 import org.apache.lucene.tests.util.TestRuleMarkFailure;
@@ -47,9 +48,9 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.IndexSettings;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.store.FsDirectoryFactory;
 import org.opensearch.index.store.Store;
@@ -63,10 +64,15 @@
 import java.io.PrintStream;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Random;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 public class MockFSDirectoryFactory implements IndexStorePlugin.DirectoryFactory {
+    public static final List<IndexModule.Type> FILE_SYSTEM_BASED_STORE_TYPES = Arrays.stream(IndexModule.Type.values())
+        .filter(t -> (t == IndexModule.Type.REMOTE_SNAPSHOT) == false)
+        .collect(Collectors.toUnmodifiableList());
 
     public static final Setting<Double> RANDOM_IO_EXCEPTION_RATE_ON_OPEN_SETTING = Setting.doubleSetting(
         "index.store.mock.random.io_exception_rate_on_open",
@@ -168,7 +174,7 @@ private Directory randomDirectoryService(Random random, IndexSettings indexSetti
                     .put(indexSettings.getIndexMetadata().getSettings())
                     .put(
                         IndexModule.INDEX_STORE_TYPE_SETTING.getKey(),
-                        RandomPicks.randomFrom(random, IndexModule.Type.values()).getSettingsKey()
+                        RandomPicks.randomFrom(random, FILE_SYSTEM_BASED_STORE_TYPES).getSettingsKey()
                     )
             )
             .build();
diff --git a/test/framework/src/main/java/org/opensearch/test/store/MockFSIndexStore.java b/test/framework/src/main/java/org/opensearch/test/store/MockFSIndexStore.java
index 88e4d0909a6fa..60bf0f3ae3322 100644
--- a/test/framework/src/main/java/org/opensearch/test/store/MockFSIndexStore.java
+++ b/test/framework/src/main/java/org/opensearch/test/store/MockFSIndexStore.java
@@ -38,11 +38,11 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexModule;
 import org.opensearch.index.shard.IndexEventListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.shard.IndexShardState;
-import org.opensearch.index.shard.ShardId;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.plugins.Plugin;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManager.java b/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManager.java
index e60871f67ea54..677ec7a0a6600 100644
--- a/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManager.java
+++ b/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManager.java
@@ -39,6 +39,7 @@
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.tasks.Task;
 import org.opensearch.tasks.TaskAwareRequest;
 import org.opensearch.tasks.TaskManager;
@@ -127,6 +128,21 @@ public void waitForTaskCompletion(Task task, long untilInNanos) {
         super.waitForTaskCompletion(task, untilInNanos);
     }
 
+    @Override
+    public ThreadContext.StoredContext taskExecutionStarted(Task task) {
+        for (MockTaskManagerListener listener : listeners) {
+            listener.taskExecutionStarted(task, false);
+        }
+
+        ThreadContext.StoredContext storedContext = super.taskExecutionStarted(task);
+        return () -> {
+            for (MockTaskManagerListener listener : listeners) {
+                listener.taskExecutionStarted(task, true);
+            }
+            storedContext.restore();
+        };
+    }
+
     public void addListener(MockTaskManagerListener listener) {
         listeners.add(listener);
     }
diff --git a/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManagerListener.java b/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManagerListener.java
index eb8361ac552fc..f15f878995aa2 100644
--- a/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManagerListener.java
+++ b/test/framework/src/main/java/org/opensearch/test/tasks/MockTaskManagerListener.java
@@ -43,4 +43,7 @@ public interface MockTaskManagerListener {
     void onTaskUnregistered(Task task);
 
     void waitForTaskCompletion(Task task);
+
+    void taskExecutionStarted(Task task, Boolean closeableInvoked);
+
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetry.java b/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetry.java
new file mode 100644
index 0000000000000..95321a7009be9
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetry.java
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry;
+
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+import org.opensearch.telemetry.metrics.Counter;
+import org.opensearch.telemetry.metrics.MetricsTelemetry;
+import org.opensearch.telemetry.tracing.TracingTelemetry;
+import org.opensearch.test.telemetry.tracing.MockTracingTelemetry;
+
+/**
+ * Mock {@link Telemetry} implementation for testing.
+ */
+public class MockTelemetry implements Telemetry {
+    /**
+     * Constructor with settings.
+     * @param settings telemetry settings.
+     */
+    public MockTelemetry(TelemetrySettings settings) {
+
+    }
+
+    @Override
+    public TracingTelemetry getTracingTelemetry() {
+        return new MockTracingTelemetry();
+    }
+
+    @Override
+    public MetricsTelemetry getMetricsTelemetry() {
+        return new MetricsTelemetry() {
+            @Override
+            public Counter createCounter(String name, String description, String unit) {
+                return null;
+            }
+
+            @Override
+            public Counter createUpDownCounter(String name, String description, String unit) {
+                return null;
+            }
+
+            @Override
+            public void close() {
+
+            }
+        };
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetryPlugin.java b/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetryPlugin.java
new file mode 100644
index 0000000000000..4f483098caf82
--- /dev/null
+++ b/test/framework/src/main/java/org/opensearch/test/telemetry/MockTelemetryPlugin.java
@@ -0,0 +1,40 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry;
+
+import org.opensearch.plugins.Plugin;
+import org.opensearch.plugins.TelemetryPlugin;
+import org.opensearch.telemetry.Telemetry;
+import org.opensearch.telemetry.TelemetrySettings;
+
+import java.util.Optional;
+
+/**
+ * Mock {@link TelemetryPlugin} implementation for testing.
+ */
+public class MockTelemetryPlugin extends Plugin implements TelemetryPlugin {
+    private static final String MOCK_TRACER_NAME = "mock";
+
+    /**
+     * Base constructor.
+     */
+    public MockTelemetryPlugin() {
+
+    }
+
+    @Override
+    public Optional<Telemetry> getTelemetry(TelemetrySettings settings) {
+        return Optional.of(new MockTelemetry(settings));
+    }
+
+    @Override
+    public String getName() {
+        return MOCK_TRACER_NAME;
+    }
+}
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/CapturingTransport.java b/test/framework/src/main/java/org/opensearch/test/transport/CapturingTransport.java
index f49f500d1431c..5e2c724e4e1e3 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/CapturingTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/CapturingTransport.java
@@ -36,6 +36,7 @@
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportRequest;
+import org.opensearch.transport.TransportRequestOptions;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -54,12 +55,14 @@ public static class CapturedRequest {
         public final long requestId;
         public final String action;
         public final TransportRequest request;
+        public final TransportRequestOptions options;
 
-        CapturedRequest(DiscoveryNode node, long requestId, String action, TransportRequest request) {
+        CapturedRequest(DiscoveryNode node, long requestId, String action, TransportRequest request, TransportRequestOptions options) {
             this.node = node;
             this.requestId = requestId;
             this.action = action;
             this.request = request;
+            this.options = options;
         }
     }
 
@@ -123,6 +126,16 @@ public void clear() {
     }
 
     protected void onSendRequest(long requestId, String action, TransportRequest request, DiscoveryNode node) {
-        capturedRequests.add(new CapturingTransport.CapturedRequest(node, requestId, action, request));
+        capturedRequests.add(new CapturingTransport.CapturedRequest(node, requestId, action, request, null));
+    }
+
+    protected void onSendRequest(
+        long requestId,
+        String action,
+        TransportRequest request,
+        DiscoveryNode node,
+        TransportRequestOptions options
+    ) {
+        capturedRequests.add(new CapturingTransport.CapturedRequest(node, requestId, action, request, options));
     }
 }
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/FakeTransport.java b/test/framework/src/main/java/org/opensearch/test/transport/FakeTransport.java
index b0aea3d2e3841..c0cfac956d890 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/FakeTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/FakeTransport.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.test.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.component.AbstractLifecycleComponent;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.common.lifecycle.AbstractLifecycleComponent;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.transport.CloseableConnection;
 import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.Transport;
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/MockTransport.java b/test/framework/src/main/java/org/opensearch/test/transport/MockTransport.java
index e1e5bcc968047..24aef714cc259 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/MockTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/MockTransport.java
@@ -38,11 +38,14 @@
 import org.opensearch.common.Randomness;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.CloseableConnection;
 import org.opensearch.transport.ClusterConnectionManager;
@@ -53,7 +56,6 @@
 import org.opensearch.transport.TransportMessageListener;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestOptions;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -79,7 +81,8 @@ public TransportService createTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
         StubbableConnectionManager connectionManager = new StubbableConnectionManager(new ClusterConnectionManager(settings, this));
         connectionManager.setDefaultNodeConnectedBehavior((cm, node) -> false);
@@ -92,7 +95,8 @@ public TransportService createTransportService(
             localNodeFactory,
             clusterSettings,
             taskHeaders,
-            connectionManager
+            connectionManager,
+            tracer
         );
     }
 
@@ -151,7 +155,7 @@ public void handleRemoteError(final long requestId, final Throwable t) {
         } else {
             try (BytesStreamOutput output = new BytesStreamOutput()) {
                 output.writeException(t);
-                remoteException = new RemoteTransportException("remote failure", output.bytes().streamInput().readException());
+                remoteException = new RemoteTransportException("remote failure", output.bytes().<StreamInput>streamInput().readException());
             } catch (IOException ioException) {
                 throw new AssertionError("failed to serialize/deserialize supplied exception " + t, ioException);
             }
@@ -188,13 +192,23 @@ public DiscoveryNode getNode() {
             public void sendRequest(long requestId, String action, TransportRequest request, TransportRequestOptions options)
                 throws TransportException {
                 requests.put(requestId, Tuple.tuple(node, action));
-                onSendRequest(requestId, action, request, node);
+                onSendRequest(requestId, action, request, node, options);
             }
         };
     }
 
     protected void onSendRequest(long requestId, String action, TransportRequest request, DiscoveryNode node) {}
 
+    protected void onSendRequest(
+        long requestId,
+        String action,
+        TransportRequest request,
+        DiscoveryNode node,
+        TransportRequestOptions options
+    ) {
+        onSendRequest(requestId, action, request, node);
+    }
+
     @Override
     public void setMessageListener(TransportMessageListener listener) {
         if (this.listener != null) {
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/MockTransportService.java b/test/framework/src/main/java/org/opensearch/test/transport/MockTransportService.java
index 9b9baebd540c3..760bcbde8fb34 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/MockTransportService.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/MockTransportService.java
@@ -35,33 +35,35 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.MockPageCacheRecycler;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.RunOnce;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.node.Node;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.tasks.TaskManager;
+import org.opensearch.telemetry.tracing.Tracer;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.tasks.MockTaskManager;
 import org.opensearch.threadpool.ThreadPool;
-import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.ClusterConnectionManager;
+import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.RequestHandlerRegistry;
 import org.opensearch.transport.Transport;
@@ -114,18 +116,19 @@ public List<Setting<?>> getSettings() {
         }
     }
 
-    public static MockTransportService createNewService(Settings settings, Version version, ThreadPool threadPool) {
-        return createNewService(settings, version, threadPool, null);
+    public static MockTransportService createNewService(Settings settings, Version version, ThreadPool threadPool, Tracer tracer) {
+        return createNewService(settings, version, threadPool, null, tracer);
     }
 
     public static MockTransportService createNewService(
         Settings settings,
         Version version,
         ThreadPool threadPool,
-        @Nullable ClusterSettings clusterSettings
+        @Nullable ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         MockNioTransport mockTransport = newMockTransport(settings, version, threadPool);
-        return createNewService(settings, mockTransport, version, threadPool, clusterSettings, Collections.emptySet());
+        return createNewService(settings, mockTransport, version, threadPool, clusterSettings, Collections.emptySet(), tracer);
     }
 
     public static MockNioTransport newMockTransport(Settings settings, Version version, ThreadPool threadPool) {
@@ -138,7 +141,8 @@ public static MockNioTransport newMockTransport(Settings settings, Version versi
             new NetworkService(Collections.emptyList()),
             new MockPageCacheRecycler(settings),
             namedWriteableRegistry,
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         );
     }
 
@@ -148,9 +152,10 @@ public static MockTransportService createNewService(
         Version version,
         ThreadPool threadPool,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
-        return createNewService(settings, transport, version, threadPool, clusterSettings, taskHeaders, NOOP_TRANSPORT_INTERCEPTOR);
+        return createNewService(settings, transport, version, threadPool, clusterSettings, taskHeaders, NOOP_TRANSPORT_INTERCEPTOR, tracer);
     }
 
     public static MockTransportService createNewService(
@@ -160,7 +165,8 @@ public static MockTransportService createNewService(
         ThreadPool threadPool,
         @Nullable ClusterSettings clusterSettings,
         Set<String> taskHeaders,
-        TransportInterceptor interceptor
+        TransportInterceptor interceptor,
+        Tracer tracer
     ) {
         return new MockTransportService(
             settings,
@@ -176,7 +182,8 @@ public static MockTransportService createNewService(
                 version
             ),
             clusterSettings,
-            taskHeaders
+            taskHeaders,
+            tracer
         );
     }
 
@@ -194,7 +201,8 @@ public MockTransportService(
         Transport transport,
         ThreadPool threadPool,
         TransportInterceptor interceptor,
-        @Nullable ClusterSettings clusterSettings
+        @Nullable ClusterSettings clusterSettings,
+        Tracer tracer
     ) {
         this(
             settings,
@@ -207,7 +215,8 @@ public MockTransportService(
                 settings.get(Node.NODE_NAME_SETTING.getKey(), UUIDs.randomBase64UUID())
             ),
             clusterSettings,
-            Collections.emptySet()
+            Collections.emptySet(),
+            tracer
         );
     }
 
@@ -225,9 +234,10 @@ public MockTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
-        this(settings, new StubbableTransport(transport), threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders);
+        this(settings, new StubbableTransport(transport), threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders, tracer);
     }
 
     private MockTransportService(
@@ -237,7 +247,8 @@ private MockTransportService(
         TransportInterceptor interceptor,
         Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
         @Nullable ClusterSettings clusterSettings,
-        Set<String> taskHeaders
+        Set<String> taskHeaders,
+        Tracer tracer
     ) {
         super(
             settings,
@@ -247,7 +258,8 @@ private MockTransportService(
             localNodeFactory,
             clusterSettings,
             taskHeaders,
-            new StubbableConnectionManager(new ClusterConnectionManager(settings, transport))
+            new StubbableConnectionManager(new ClusterConnectionManager(settings, transport)),
+            tracer
         );
         this.original = transport.getDelegate();
     }
@@ -261,11 +273,16 @@ private static TransportAddress[] extractTransportAddresses(TransportService tra
     }
 
     @Override
-    protected TaskManager createTaskManager(Settings settings, ThreadPool threadPool, Set<String> taskHeaders) {
+    protected TaskManager createTaskManager(
+        Settings settings,
+        ClusterSettings clusterSettings,
+        ThreadPool threadPool,
+        Set<String> taskHeaders
+    ) {
         if (MockTaskManager.USE_MOCK_TASK_MANAGER_SETTING.get(settings)) {
             return new MockTaskManager(settings, threadPool, taskHeaders);
         } else {
-            return super.createTaskManager(settings, threadPool, taskHeaders);
+            return super.createTaskManager(settings, clusterSettings, threadPool, taskHeaders);
         }
     }
 
@@ -530,7 +547,6 @@ public void clearCallback() {
 
     /**
      * Adds a new handling behavior that is used when the defined request is received.
-     *
      */
     public <R extends TransportRequest> void addRequestHandlingBehavior(
         String actionName,
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/StubbableConnectionManager.java b/test/framework/src/main/java/org/opensearch/test/transport/StubbableConnectionManager.java
index 53cae12871d92..37df90fb103a3 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/StubbableConnectionManager.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/StubbableConnectionManager.java
@@ -31,12 +31,12 @@
 
 package org.opensearch.test.transport;
 
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.transport.ConnectTransportException;
-import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.ConnectionManager;
+import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportConnectionListener;
 
diff --git a/test/framework/src/main/java/org/opensearch/test/transport/StubbableTransport.java b/test/framework/src/main/java/org/opensearch/test/transport/StubbableTransport.java
index 8c3b32dbb4ca4..11e1bdf8dbcd6 100644
--- a/test/framework/src/main/java/org/opensearch/test/transport/StubbableTransport.java
+++ b/test/framework/src/main/java/org/opensearch/test/transport/StubbableTransport.java
@@ -33,12 +33,12 @@
 package org.opensearch.test.transport;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.component.Lifecycle;
-import org.opensearch.common.component.LifecycleListener;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.common.lifecycle.Lifecycle;
+import org.opensearch.common.lifecycle.LifecycleListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.RequestHandlerRegistry;
diff --git a/test/framework/src/main/java/org/opensearch/threadpool/TestThreadPool.java b/test/framework/src/main/java/org/opensearch/threadpool/TestThreadPool.java
index 5f8611d99f0a0..2d97d5bffee01 100644
--- a/test/framework/src/main/java/org/opensearch/threadpool/TestThreadPool.java
+++ b/test/framework/src/main/java/org/opensearch/threadpool/TestThreadPool.java
@@ -40,6 +40,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.atomic.AtomicReference;
 
 public class TestThreadPool extends ThreadPool {
 
@@ -47,12 +48,29 @@ public class TestThreadPool extends ThreadPool {
     private volatile boolean returnRejectingExecutor = false;
     private volatile ThreadPoolExecutor rejectingExecutor;
 
+    public TestThreadPool(
+        String name,
+        AtomicReference<RunnableTaskExecutionListener> runnableTaskListener,
+        ExecutorBuilder<?>... customBuilders
+    ) {
+        this(name, Settings.EMPTY, runnableTaskListener, customBuilders);
+    }
+
     public TestThreadPool(String name, ExecutorBuilder<?>... customBuilders) {
         this(name, Settings.EMPTY, customBuilders);
     }
 
     public TestThreadPool(String name, Settings settings, ExecutorBuilder<?>... customBuilders) {
-        super(Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), name).put(settings).build(), customBuilders);
+        this(name, settings, null, customBuilders);
+    }
+
+    public TestThreadPool(
+        String name,
+        Settings settings,
+        AtomicReference<RunnableTaskExecutionListener> runnableTaskListener,
+        ExecutorBuilder<?>... customBuilders
+    ) {
+        super(Settings.builder().put(Node.NODE_NAME_SETTING.getKey(), name).put(settings).build(), runnableTaskListener, customBuilders);
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/opensearch/transport/AbstractSimpleTransportTestCase.java b/test/framework/src/main/java/org/opensearch/transport/AbstractSimpleTransportTestCase.java
index ec88cd0201db5..7baa90ede4012 100644
--- a/test/framework/src/main/java/org/opensearch/transport/AbstractSimpleTransportTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/transport/AbstractSimpleTransportTestCase.java
@@ -39,35 +39,37 @@
 import org.apache.logging.log4j.util.Supplier;
 import org.apache.lucene.util.CollectionUtil;
 import org.apache.lucene.util.Constants;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.OpenSearchException;
-import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionListenerResponseHandler;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.network.CloseableChannel;
 import org.opensearch.common.network.NetworkAddress;
 import org.opensearch.common.network.NetworkUtils;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.BoundTransportAddress;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
 import org.opensearch.common.util.concurrent.ConcurrentCollections;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.transport.BoundTransportAddress;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.node.Node;
 import org.opensearch.tasks.Task;
-import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.VersionUtils;
 import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.test.transport.MockTransportService;
@@ -227,7 +229,8 @@ private MockTransportService buildService(
             threadPool,
             clusterSettings,
             Collections.emptySet(),
-            interceptor
+            interceptor,
+            NoopTracer.INSTANCE
         );
         service.start();
         if (acceptRequests) {
@@ -2109,7 +2112,9 @@ public void testRegisterHandlerTwice() {
             "internal:action1",
             randomFrom(ThreadPool.Names.SAME, ThreadPool.Names.GENERIC),
             TestRequest::new,
-            (request, message, task) -> { throw new AssertionError("boom"); }
+            (request, message, task) -> {
+                throw new AssertionError("boom");
+            }
         );
         expectThrows(
             IllegalArgumentException.class,
@@ -2117,7 +2122,9 @@ public void testRegisterHandlerTwice() {
                 "internal:action1",
                 randomFrom(ThreadPool.Names.SAME, ThreadPool.Names.GENERIC),
                 TestRequest::new,
-                (request, message, task) -> { throw new AssertionError("boom"); }
+                (request, message, task) -> {
+                    throw new AssertionError("boom");
+                }
             )
         );
 
@@ -2125,7 +2132,9 @@ public void testRegisterHandlerTwice() {
             "internal:action1",
             randomFrom(ThreadPool.Names.SAME, ThreadPool.Names.GENERIC),
             TestRequest::new,
-            (request, message, task) -> { throw new AssertionError("boom"); }
+            (request, message, task) -> {
+                throw new AssertionError("boom");
+            }
         );
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/transport/FakeTcpChannel.java b/test/framework/src/main/java/org/opensearch/transport/FakeTcpChannel.java
index 73694bc88bd67..786c2ffc05a19 100644
--- a/test/framework/src/main/java/org/opensearch/transport/FakeTcpChannel.java
+++ b/test/framework/src/main/java/org/opensearch/transport/FakeTcpChannel.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.concurrent.CompletableContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.bytes.BytesReference;
 
 import java.net.InetSocketAddress;
 import java.util.concurrent.atomic.AtomicReference;
diff --git a/test/framework/src/main/java/org/opensearch/transport/TestRequest.java b/test/framework/src/main/java/org/opensearch/transport/TestRequest.java
index 29a907a45a925..2fe917235e948 100644
--- a/test/framework/src/main/java/org/opensearch/transport/TestRequest.java
+++ b/test/framework/src/main/java/org/opensearch/transport/TestRequest.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/transport/TestResponse.java b/test/framework/src/main/java/org/opensearch/transport/TestResponse.java
index ba6db406033dd..14db8b3372bf2 100644
--- a/test/framework/src/main/java/org/opensearch/transport/TestResponse.java
+++ b/test/framework/src/main/java/org/opensearch/transport/TestResponse.java
@@ -31,8 +31,9 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.transport.TransportResponse;
 
 import java.io.IOException;
 
diff --git a/test/framework/src/main/java/org/opensearch/transport/TestTransportChannel.java b/test/framework/src/main/java/org/opensearch/transport/TestTransportChannel.java
index 819094c9fb089..e0852cf882345 100644
--- a/test/framework/src/main/java/org/opensearch/transport/TestTransportChannel.java
+++ b/test/framework/src/main/java/org/opensearch/transport/TestTransportChannel.java
@@ -32,7 +32,8 @@
 
 package org.opensearch.transport;
 
-import org.opensearch.action.ActionListener;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.transport.TransportResponse;
 
 public class TestTransportChannel implements TransportChannel {
 
diff --git a/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransport.java b/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransport.java
index 261097a9d648a..cd6bf02efef6f 100644
--- a/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransport.java
+++ b/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransport.java
@@ -37,14 +37,9 @@
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.breaker.CircuitBreaker;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.bytes.CompositeBytesReference;
 import org.opensearch.common.bytes.ReleasableBytesReference;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.network.NetworkService;
@@ -52,8 +47,13 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.core.internal.io.IOUtils;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.common.util.io.IOUtils;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.breaker.CircuitBreaker;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.common.bytes.CompositeBytesReference;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.nio.BytesChannelContext;
 import org.opensearch.nio.BytesWriteHandler;
 import org.opensearch.nio.ChannelFactory;
@@ -65,6 +65,7 @@
 import org.opensearch.nio.NioSocketChannel;
 import org.opensearch.nio.Page;
 import org.opensearch.nio.ServerChannelContext;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ConnectionProfile;
 import org.opensearch.transport.InboundPipeline;
@@ -110,9 +111,10 @@ public MockNioTransport(
         NetworkService networkService,
         PageCacheRecycler pageCacheRecycler,
         NamedWriteableRegistry namedWriteableRegistry,
-        CircuitBreakerService circuitBreakerService
+        CircuitBreakerService circuitBreakerService,
+        Tracer tracer
     ) {
-        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService);
+        super(settings, version, threadPool, pageCacheRecycler, circuitBreakerService, namedWriteableRegistry, networkService, tracer);
         this.transportThreadWatchdog = new TransportThreadWatchdog(threadPool, settings);
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransportPlugin.java b/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransportPlugin.java
index 01bd098487c9f..deb489614be26 100644
--- a/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransportPlugin.java
+++ b/test/framework/src/main/java/org/opensearch/transport/nio/MockNioTransportPlugin.java
@@ -32,13 +32,14 @@
 package org.opensearch.transport.nio;
 
 import org.opensearch.Version;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
-import org.opensearch.indices.breaker.CircuitBreakerService;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.indices.breaker.CircuitBreakerService;
 import org.opensearch.plugins.NetworkPlugin;
 import org.opensearch.plugins.Plugin;
+import org.opensearch.telemetry.tracing.Tracer;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.Transport;
 
@@ -57,7 +58,8 @@ public Map<String, Supplier<Transport>> getTransports(
         PageCacheRecycler pageCacheRecycler,
         CircuitBreakerService circuitBreakerService,
         NamedWriteableRegistry namedWriteableRegistry,
-        NetworkService networkService
+        NetworkService networkService,
+        Tracer tracer
     ) {
         return Collections.singletonMap(
             MOCK_NIO_TRANSPORT_NAME,
@@ -68,7 +70,8 @@ public Map<String, Supplier<Transport>> getTransports(
                 networkService,
                 pageCacheRecycler,
                 namedWriteableRegistry,
-                circuitBreakerService
+                circuitBreakerService,
+                tracer
             )
         );
     }
diff --git a/test/framework/src/main/resources/mockito-extensions/org.mockito.plugins.MockMaker b/test/framework/src/main/resources/mockito-extensions/org.mockito.plugins.MockMaker
index e1795b7b9b3d6..99b0d419fc445 100644
--- a/test/framework/src/main/resources/mockito-extensions/org.mockito.plugins.MockMaker
+++ b/test/framework/src/main/resources/mockito-extensions/org.mockito.plugins.MockMaker
@@ -1 +1 @@
-org.opensearch.mockito.plugin.PriviledgedMockMaker
\ No newline at end of file
+org.opensearch.mockito.plugin.PriviledgedMockMaker
diff --git a/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerServiceTests.java b/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerServiceTests.java
new file mode 100644
index 0000000000000..b781e54eb0c3d
--- /dev/null
+++ b/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolClusterManagerServiceTests.java
@@ -0,0 +1,183 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.cluster.service;
+
+import org.opensearch.Version;
+import org.opensearch.action.support.replication.ClusterStateCreationUtils;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.ClusterStateUpdateTask;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.concurrent.ThreadContext;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.threadpool.ThreadPool;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasToString;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class FakeThreadPoolClusterManagerServiceTests extends OpenSearchTestCase {
+
+    public void testFakeClusterManagerService() {
+        List<Runnable> runnableTasks = new ArrayList<>();
+        AtomicReference<ClusterState> lastClusterStateRef = new AtomicReference<>();
+        DiscoveryNode discoveryNode = new DiscoveryNode(
+            "node",
+            OpenSearchTestCase.buildNewFakeTransportAddress(),
+            Collections.emptyMap(),
+            new HashSet<>(DiscoveryNodeRole.BUILT_IN_ROLES),
+            Version.CURRENT
+        );
+        lastClusterStateRef.set(ClusterStateCreationUtils.state(discoveryNode, discoveryNode));
+        long firstClusterStateVersion = lastClusterStateRef.get().version();
+        AtomicReference<ActionListener<Void>> publishingCallback = new AtomicReference<>();
+        final ThreadContext context = new ThreadContext(Settings.EMPTY);
+        final ThreadPool mockThreadPool = mock(ThreadPool.class);
+        when(mockThreadPool.getThreadContext()).thenReturn(context);
+
+        final ExecutorService executorService = mock(ExecutorService.class);
+        doAnswer(invocationOnMock -> runnableTasks.add((Runnable) invocationOnMock.getArguments()[0])).when(executorService).execute(any());
+        when(mockThreadPool.generic()).thenReturn(executorService);
+
+        FakeThreadPoolClusterManagerService clusterManagerService = new FakeThreadPoolClusterManagerService(
+            "test_node",
+            "test",
+            mockThreadPool,
+            runnableTasks::add
+        );
+        clusterManagerService.setClusterStateSupplier(lastClusterStateRef::get);
+        clusterManagerService.setClusterStatePublisher((event, publishListener, ackListener) -> {
+            lastClusterStateRef.set(event.state());
+            publishingCallback.set(publishListener);
+        });
+        clusterManagerService.start();
+
+        AtomicBoolean firstTaskCompleted = new AtomicBoolean();
+        clusterManagerService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                return ClusterState.builder(currentState)
+                    .metadata(Metadata.builder(currentState.metadata()).put(indexBuilder("test1")))
+                    .build();
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                assertFalse(firstTaskCompleted.get());
+                firstTaskCompleted.set(true);
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                throw new AssertionError();
+            }
+        });
+        assertThat(runnableTasks.size(), equalTo(1));
+        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(0));
+        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion));
+        assertNull(publishingCallback.get());
+        assertFalse(firstTaskCompleted.get());
+
+        final Runnable scheduleTask = runnableTasks.remove(0);
+        assertThat(scheduleTask, hasToString("cluster-manager service scheduling next task"));
+        scheduleTask.run();
+
+        final Runnable publishTask = runnableTasks.remove(0);
+        assertThat(publishTask, hasToString(containsString("publish change of cluster state")));
+        publishTask.run();
+
+        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(1));
+        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion + 1));
+        assertNotNull(publishingCallback.get());
+        assertFalse(firstTaskCompleted.get());
+        assertThat(runnableTasks.size(), equalTo(0));
+
+        AtomicBoolean secondTaskCompleted = new AtomicBoolean();
+        clusterManagerService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
+            @Override
+            public ClusterState execute(ClusterState currentState) {
+                return ClusterState.builder(currentState)
+                    .metadata(Metadata.builder(currentState.metadata()).put(indexBuilder("test2")))
+                    .build();
+            }
+
+            @Override
+            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                assertFalse(secondTaskCompleted.get());
+                secondTaskCompleted.set(true);
+            }
+
+            @Override
+            public void onFailure(String source, Exception e) {
+                throw new AssertionError();
+            }
+        });
+        assertThat(runnableTasks.size(), equalTo(0));
+
+        publishingCallback.getAndSet(null).onResponse(null);
+        assertTrue(firstTaskCompleted.get());
+        assertThat(runnableTasks.size(), equalTo(1)); // check that new task gets queued
+
+        runnableTasks.remove(0).run(); // schedule again
+        runnableTasks.remove(0).run(); // publish again
+        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(2));
+        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion + 2));
+        assertNotNull(publishingCallback.get());
+        assertFalse(secondTaskCompleted.get());
+        publishingCallback.getAndSet(null).onResponse(null);
+        assertTrue(secondTaskCompleted.get());
+        assertThat(runnableTasks.size(), equalTo(0)); // check that no more tasks are queued
+    }
+
+    private static IndexMetadata.Builder indexBuilder(String index) {
+        return IndexMetadata.builder(index)
+            .settings(
+                settings(Version.CURRENT).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            );
+    }
+}
diff --git a/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolMasterServiceTests.java b/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolMasterServiceTests.java
deleted file mode 100644
index 4f321019a37ac..0000000000000
--- a/test/framework/src/test/java/org/opensearch/cluster/service/FakeThreadPoolMasterServiceTests.java
+++ /dev/null
@@ -1,183 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.cluster.service;
-
-import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
-import org.opensearch.action.support.replication.ClusterStateCreationUtils;
-import org.opensearch.cluster.ClusterState;
-import org.opensearch.cluster.ClusterStateUpdateTask;
-import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.cluster.metadata.Metadata;
-import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.node.DiscoveryNodeRole;
-import org.opensearch.common.settings.Settings;
-import org.opensearch.common.util.concurrent.ThreadContext;
-import org.opensearch.test.OpenSearchTestCase;
-import org.opensearch.threadpool.ThreadPool;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
-
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.hasToString;
-import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.doAnswer;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-public class FakeThreadPoolMasterServiceTests extends OpenSearchTestCase {
-
-    public void testFakeMasterService() {
-        List<Runnable> runnableTasks = new ArrayList<>();
-        AtomicReference<ClusterState> lastClusterStateRef = new AtomicReference<>();
-        DiscoveryNode discoveryNode = new DiscoveryNode(
-            "node",
-            OpenSearchTestCase.buildNewFakeTransportAddress(),
-            Collections.emptyMap(),
-            new HashSet<>(DiscoveryNodeRole.BUILT_IN_ROLES),
-            Version.CURRENT
-        );
-        lastClusterStateRef.set(ClusterStateCreationUtils.state(discoveryNode, discoveryNode));
-        long firstClusterStateVersion = lastClusterStateRef.get().version();
-        AtomicReference<ActionListener<Void>> publishingCallback = new AtomicReference<>();
-        final ThreadContext context = new ThreadContext(Settings.EMPTY);
-        final ThreadPool mockThreadPool = mock(ThreadPool.class);
-        when(mockThreadPool.getThreadContext()).thenReturn(context);
-
-        final ExecutorService executorService = mock(ExecutorService.class);
-        doAnswer(invocationOnMock -> runnableTasks.add((Runnable) invocationOnMock.getArguments()[0])).when(executorService).execute(any());
-        when(mockThreadPool.generic()).thenReturn(executorService);
-
-        FakeThreadPoolMasterService masterService = new FakeThreadPoolMasterService(
-            "test_node",
-            "test",
-            mockThreadPool,
-            runnableTasks::add
-        );
-        masterService.setClusterStateSupplier(lastClusterStateRef::get);
-        masterService.setClusterStatePublisher((event, publishListener, ackListener) -> {
-            lastClusterStateRef.set(event.state());
-            publishingCallback.set(publishListener);
-        });
-        masterService.start();
-
-        AtomicBoolean firstTaskCompleted = new AtomicBoolean();
-        masterService.submitStateUpdateTask("test1", new ClusterStateUpdateTask() {
-            @Override
-            public ClusterState execute(ClusterState currentState) {
-                return ClusterState.builder(currentState)
-                    .metadata(Metadata.builder(currentState.metadata()).put(indexBuilder("test1")))
-                    .build();
-            }
-
-            @Override
-            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
-                assertFalse(firstTaskCompleted.get());
-                firstTaskCompleted.set(true);
-            }
-
-            @Override
-            public void onFailure(String source, Exception e) {
-                throw new AssertionError();
-            }
-        });
-        assertThat(runnableTasks.size(), equalTo(1));
-        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(0));
-        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion));
-        assertNull(publishingCallback.get());
-        assertFalse(firstTaskCompleted.get());
-
-        final Runnable scheduleTask = runnableTasks.remove(0);
-        assertThat(scheduleTask, hasToString("master service scheduling next task"));
-        scheduleTask.run();
-
-        final Runnable publishTask = runnableTasks.remove(0);
-        assertThat(publishTask, hasToString(containsString("publish change of cluster state")));
-        publishTask.run();
-
-        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(1));
-        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion + 1));
-        assertNotNull(publishingCallback.get());
-        assertFalse(firstTaskCompleted.get());
-        assertThat(runnableTasks.size(), equalTo(0));
-
-        AtomicBoolean secondTaskCompleted = new AtomicBoolean();
-        masterService.submitStateUpdateTask("test2", new ClusterStateUpdateTask() {
-            @Override
-            public ClusterState execute(ClusterState currentState) {
-                return ClusterState.builder(currentState)
-                    .metadata(Metadata.builder(currentState.metadata()).put(indexBuilder("test2")))
-                    .build();
-            }
-
-            @Override
-            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
-                assertFalse(secondTaskCompleted.get());
-                secondTaskCompleted.set(true);
-            }
-
-            @Override
-            public void onFailure(String source, Exception e) {
-                throw new AssertionError();
-            }
-        });
-        assertThat(runnableTasks.size(), equalTo(0));
-
-        publishingCallback.getAndSet(null).onResponse(null);
-        assertTrue(firstTaskCompleted.get());
-        assertThat(runnableTasks.size(), equalTo(1)); // check that new task gets queued
-
-        runnableTasks.remove(0).run(); // schedule again
-        runnableTasks.remove(0).run(); // publish again
-        assertThat(lastClusterStateRef.get().metadata().indices().size(), equalTo(2));
-        assertThat(lastClusterStateRef.get().version(), equalTo(firstClusterStateVersion + 2));
-        assertNotNull(publishingCallback.get());
-        assertFalse(secondTaskCompleted.get());
-        publishingCallback.getAndSet(null).onResponse(null);
-        assertTrue(secondTaskCompleted.get());
-        assertThat(runnableTasks.size(), equalTo(0)); // check that no more tasks are queued
-    }
-
-    private static IndexMetadata.Builder indexBuilder(String index) {
-        return IndexMetadata.builder(index)
-            .settings(
-                settings(Version.CURRENT).put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-            );
-    }
-}
diff --git a/test/framework/src/test/java/org/opensearch/common/hash/HashFunctionTestCaseTests.java b/test/framework/src/test/java/org/opensearch/common/hash/HashFunctionTestCaseTests.java
new file mode 100644
index 0000000000000..d5fdaf10999fc
--- /dev/null
+++ b/test/framework/src/test/java/org/opensearch/common/hash/HashFunctionTestCaseTests.java
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common.hash;
+
+import org.apache.lucene.util.StringHelper;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.nio.ByteOrder;
+import java.util.Arrays;
+
+public class HashFunctionTestCaseTests extends OpenSearchTestCase {
+    private static final VarHandle INT_HANDLE = MethodHandles.byteArrayViewVarHandle(int[].class, ByteOrder.LITTLE_ENDIAN);
+
+    /**
+     * Asserts the positive case where a hash function passes the avalanche test.
+     */
+    public void testStrongHashFunction() {
+        HashFunctionTestCase murmur3 = new HashFunctionTestCase() {
+            private final byte[] scratch = new byte[4];
+
+            @Override
+            public byte[] hash(byte[] input) {
+                int hash = StringHelper.murmurhash3_x86_32(input, 0, input.length, StringHelper.GOOD_FAST_HASH_SEED);
+                INT_HANDLE.set(scratch, 0, hash);
+                return scratch;
+            }
+
+            @Override
+            public int outputBits() {
+                return 32;
+            }
+        };
+
+        murmur3.testAvalanche();
+    }
+
+    /**
+     * Asserts the negative case where a hash function fails the avalanche test.
+     */
+    public void testWeakHashFunction() {
+        HashFunctionTestCase arraysHashCode = new HashFunctionTestCase() {
+            private final byte[] scratch = new byte[4];
+
+            @Override
+            public byte[] hash(byte[] input) {
+                int hash = Arrays.hashCode(input);
+                INT_HANDLE.set(scratch, 0, hash);
+                return scratch;
+            }
+
+            @Override
+            public int outputBits() {
+                return 32;
+            }
+        };
+
+        AssertionError ex = expectThrows(AssertionError.class, arraysHashCode::testAvalanche);
+        assertTrue(ex.getMessage().contains("bias exceeds threshold"));
+    }
+}
diff --git a/test/framework/src/test/java/org/opensearch/node/MockNodeTests.java b/test/framework/src/test/java/org/opensearch/node/MockNodeTests.java
index 48e18b4afe649..e59a7df32ffca 100644
--- a/test/framework/src/test/java/org/opensearch/node/MockNodeTests.java
+++ b/test/framework/src/test/java/org/opensearch/node/MockNodeTests.java
@@ -39,8 +39,8 @@
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.MockSearchService;
 import org.opensearch.search.SearchService;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockHttpTransport;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/test/framework/src/test/java/org/opensearch/test/AbstractXContentTestCaseTests.java b/test/framework/src/test/java/org/opensearch/test/AbstractXContentTestCaseTests.java
index c2b9ee19845a1..32cbdb62ab429 100644
--- a/test/framework/src/test/java/org/opensearch/test/AbstractXContentTestCaseTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/AbstractXContentTestCaseTests.java
@@ -34,11 +34,11 @@
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.util.Map;
 
@@ -59,14 +59,14 @@ public void testInsertRandomFieldsAndShuffle() throws Exception {
                 1,
                 () -> AbstractXContentTestCase.insertRandomFieldsAndShuffle(
                     BytesReference.bytes(builder),
-                    XContentType.JSON,
+                    MediaTypeRegistry.JSON,
                     true,
                     new String[] {},
                     null,
                     this::createParser
                 )
             );
-        try (XContentParser parser = createParser(XContentType.JSON.xContent(), insertRandomFieldsAndShuffle)) {
+        try (XContentParser parser = createParser(MediaTypeRegistry.JSON.xContent(), insertRandomFieldsAndShuffle)) {
             Map<String, Object> mapOrdered = parser.mapOrdered();
             assertThat(mapOrdered.size(), equalTo(2));
             assertThat(mapOrdered.keySet().iterator().next(), not(equalTo("field")));
diff --git a/test/framework/src/test/java/org/opensearch/test/VersionUtilsTests.java b/test/framework/src/test/java/org/opensearch/test/VersionUtilsTests.java
index 7d8fb4a318621..de1f650aff20c 100644
--- a/test/framework/src/test/java/org/opensearch/test/VersionUtilsTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/VersionUtilsTests.java
@@ -284,7 +284,6 @@ public void testResolveReleasedVersionsAtNewMinorBranchIn2x() {
                 Arrays.asList(
                     TestNewMinorBranchIn6x.V_1_6_0,
                     TestNewMinorBranchIn6x.V_1_6_1,
-                    TestNewMinorBranchIn6x.V_1_6_2,
                     TestNewMinorBranchIn6x.V_2_0_0,
                     TestNewMinorBranchIn6x.V_2_0_1,
                     TestNewMinorBranchIn6x.V_2_1_0,
@@ -292,7 +291,10 @@ public void testResolveReleasedVersionsAtNewMinorBranchIn2x() {
                 )
             )
         );
-        assertThat(unreleased, equalTo(Arrays.asList(TestNewMinorBranchIn6x.V_2_1_2, TestNewMinorBranchIn6x.V_2_2_0)));
+        assertThat(
+            unreleased,
+            equalTo(Arrays.asList(TestNewMinorBranchIn6x.V_1_6_2, TestNewMinorBranchIn6x.V_2_1_2, TestNewMinorBranchIn6x.V_2_2_0))
+        );
     }
 
     /**
diff --git a/test/framework/src/test/java/org/opensearch/test/XContentTestUtilsTests.java b/test/framework/src/test/java/org/opensearch/test/XContentTestUtilsTests.java
index f20e31d4aa368..30636f8521354 100644
--- a/test/framework/src/test/java/org/opensearch/test/XContentTestUtilsTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/XContentTestUtilsTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.test;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.DeprecationHandler;
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
-import org.opensearch.common.xcontent.XContentParser;
-import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -111,28 +111,28 @@ public void testInsertIntoXContent() throws IOException {
         builder.startObject();
         builder.endObject();
         builder = XContentTestUtils.insertIntoXContent(
-            XContentType.JSON.xContent(),
+            MediaTypeRegistry.JSON.xContent(),
             BytesReference.bytes(builder),
             Collections.singletonList(""),
             () -> "inn.er1",
             () -> new HashMap<>()
         );
         builder = XContentTestUtils.insertIntoXContent(
-            XContentType.JSON.xContent(),
+            MediaTypeRegistry.JSON.xContent(),
             BytesReference.bytes(builder),
             Collections.singletonList(""),
             () -> "field1",
             () -> "value1"
         );
         builder = XContentTestUtils.insertIntoXContent(
-            XContentType.JSON.xContent(),
+            MediaTypeRegistry.JSON.xContent(),
             BytesReference.bytes(builder),
             Collections.singletonList("inn\\.er1"),
             () -> "inner2",
             () -> new HashMap<>()
         );
         builder = XContentTestUtils.insertIntoXContent(
-            XContentType.JSON.xContent(),
+            MediaTypeRegistry.JSON.xContent(),
             BytesReference.bytes(builder),
             Collections.singletonList("inn\\.er1"),
             () -> "field2",
@@ -194,7 +194,7 @@ public void testInsertRandomXContent() throws IOException {
 
         try (
             XContentParser parser = createParser(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 insertRandomFields(builder.contentType(), BytesReference.bytes(builder), null, random())
             )
         ) {
@@ -212,7 +212,7 @@ public void testInsertRandomXContent() throws IOException {
         Predicate<String> pathsToExclude = path -> path.endsWith("foo1");
         try (
             XContentParser parser = createParser(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 insertRandomFields(builder.contentType(), BytesReference.bytes(builder), pathsToExclude, random())
             )
         ) {
@@ -230,7 +230,7 @@ public void testInsertRandomXContent() throws IOException {
         pathsToExclude = path -> path.contains("foo1");
         try (
             XContentParser parser = createParser(
-                XContentType.JSON.xContent(),
+                MediaTypeRegistry.JSON.xContent(),
                 insertRandomFields(builder.contentType(), BytesReference.bytes(builder), pathsToExclude, random())
             )
         ) {
diff --git a/test/framework/src/test/java/org/opensearch/test/disruption/DisruptableMockTransportTests.java b/test/framework/src/test/java/org/opensearch/test/disruption/DisruptableMockTransportTests.java
index e96fb4bab0453..6b64270ca68e1 100644
--- a/test/framework/src/test/java/org/opensearch/test/disruption/DisruptableMockTransportTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/disruption/DisruptableMockTransportTests.java
@@ -37,10 +37,13 @@
 import org.opensearch.cluster.coordination.DeterministicTaskQueue;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.transport.TransportResponse;
+import org.opensearch.core.transport.TransportResponse.Empty;
 import org.opensearch.node.Node;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.disruption.DisruptableMockTransport.ConnectionStatus;
 import org.opensearch.threadpool.ThreadPool;
@@ -49,8 +52,6 @@
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportRequest;
 import org.opensearch.transport.TransportRequestHandler;
-import org.opensearch.transport.TransportResponse;
-import org.opensearch.transport.TransportResponse.Empty;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 import org.junit.Before;
@@ -161,7 +162,8 @@ protected void execute(Runnable runnable) {
             NOOP_TRANSPORT_INTERCEPTOR,
             a -> node1,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
         service2 = transport2.createTransportService(
             Settings.EMPTY,
@@ -169,7 +171,8 @@ protected void execute(Runnable runnable) {
             NOOP_TRANSPORT_INTERCEPTOR,
             a -> node2,
             null,
-            Collections.emptySet()
+            Collections.emptySet(),
+            NoopTracer.INSTANCE
         );
 
         service1.start();
diff --git a/test/framework/src/test/java/org/opensearch/test/disruption/NetworkDisruptionIT.java b/test/framework/src/test/java/org/opensearch/test/disruption/NetworkDisruptionIT.java
index b58d4fd45ff93..362ecd692360d 100644
--- a/test/framework/src/test/java/org/opensearch/test/disruption/NetworkDisruptionIT.java
+++ b/test/framework/src/test/java/org/opensearch/test/disruption/NetworkDisruptionIT.java
@@ -37,16 +37,16 @@
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.opensearch.cluster.NodeConnectionsService;
 import org.opensearch.common.collect.Tuple;
-import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.transport.TransportResponse;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.InternalTestCluster;
+import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.disruption.NetworkDisruption.TwoPartitions;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
-import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportResponseHandler;
 import org.opensearch.transport.TransportService;
 
@@ -76,11 +76,11 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     /**
      * Creates 3 to 5 mixed-node cluster and splits it into 2 parts.
      * The first part is guaranteed to have at least the majority of the nodes,
-     * so that master could be elected on this side.
+     * so that cluster-manager could be elected on this side.
      */
     private Tuple<Set<String>, Set<String>> prepareDisruptedCluster() {
         int numOfNodes = randomIntBetween(3, 5);
-        internalCluster().setBootstrapMasterNodeIndex(numOfNodes - 1);
+        internalCluster().setBootstrapClusterManagerNodeIndex(numOfNodes - 1);
         Set<String> nodes = new HashSet<>(internalCluster().startNodes(numOfNodes, DISRUPTION_TUNED_SETTINGS));
         ensureGreen();
         assertThat(nodes.size(), greaterThanOrEqualTo(3));
@@ -127,7 +127,7 @@ public void testNetworkPartitionRemovalRestoresConnections() throws Exception {
     }
 
     public void testTransportRespondsEventually() throws InterruptedException {
-        internalCluster().setBootstrapMasterNodeIndex(0);
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
         internalCluster().ensureAtLeastNumDataNodes(randomIntBetween(3, 5));
         final NetworkDisruption.DisruptedLinks disruptedLinks;
         if (randomBoolean()) {
diff --git a/test/framework/src/test/java/org/opensearch/test/hamcrest/OpenSearchAssertionsTests.java b/test/framework/src/test/java/org/opensearch/test/hamcrest/OpenSearchAssertionsTests.java
index c5a022d119dd0..fe699b2355d3e 100644
--- a/test/framework/src/test/java/org/opensearch/test/hamcrest/OpenSearchAssertionsTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/hamcrest/OpenSearchAssertionsTests.java
@@ -32,15 +32,15 @@
 
 package org.opensearch.test.hamcrest;
 
-import org.opensearch.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.cluster.block.ClusterBlock;
 import org.opensearch.cluster.block.ClusterBlockException;
 import org.opensearch.cluster.metadata.IndexMetadata;
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.json.JsonXContent;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcherTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcherTests.java
deleted file mode 100644
index 05cdec242e565..0000000000000
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/BlacklistedPathPatternMatcherTests.java
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-package org.opensearch.test.rest.yaml;
-
-import org.opensearch.test.OpenSearchTestCase;
-
-public class BlacklistedPathPatternMatcherTests extends OpenSearchTestCase {
-
-    public void testMatchesExact() {
-        // suffix match
-        assertMatch("cat.aliases/10_basic/Empty cluster", "/some/suite_path/cat.aliases/10_basic/Empty cluster");
-        // exact match
-        assertMatch("cat.aliases/10_basic/Empty cluster", "cat.aliases/10_basic/Empty cluster");
-        // additional text at the end should not match
-        assertNoMatch("cat.aliases/10_basic/Empty cluster", "cat.aliases/10_basic/Empty clusters in here");
-    }
-
-    public void testMatchesSimpleWildcardPatterns() {
-        assertMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/test_first");
-        assertMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/");
-        // do not cross segment boundaries
-        assertNoMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/test/first");
-    }
-
-    public void testMatchesMultiWildcardPatterns() {
-        assertMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices");
-        assertMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all");
-        assertNoMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all/here");
-        assertMatch("indices.get/*/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all");
-        assertMatch("indices.get/*/*allow_no_indices*", "/suite/indices.get/20_basic/we_allow_no_indices_at_all");
-        assertMatch("*/*/*allow_no_indices*", "/suite/path/to/test/indices.get/20_basic/we_allow_no_indices_at_all");
-    }
-
-    public void testMatchesPatternsWithEscapedCommas() {
-        assertMatch("indices.get/10_basic\\,20_advanced/foo", "/suite/indices.get/10_basic,20_advanced/foo");
-    }
-
-    public void testMatchesMixedPatterns() {
-        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/foo");
-        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/my_foo");
-        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/foo_bar");
-    }
-
-    private void assertMatch(String pattern, String path) {
-        BlacklistedPathPatternMatcher matcher = new BlacklistedPathPatternMatcher(pattern);
-        assertTrue("Pattern [" + pattern + "] should have matched path [" + path + "]", matcher.isSuffixMatch(path));
-    }
-
-    private void assertNoMatch(String pattern, String path) {
-        BlacklistedPathPatternMatcher matcher = new BlacklistedPathPatternMatcher(pattern);
-        assertFalse("Pattern [" + pattern + "] should not have matched path [" + path + "]", matcher.isSuffixMatch(path));
-    }
-}
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcherTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcherTests.java
new file mode 100644
index 0000000000000..3d62f399fe271
--- /dev/null
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/DenylistedPathPatternMatcherTests.java
@@ -0,0 +1,82 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.test.rest.yaml;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class DenylistedPathPatternMatcherTests extends OpenSearchTestCase {
+
+    public void testMatchesExact() {
+        // suffix match
+        assertMatch("cat.aliases/10_basic/Empty cluster", "/some/suite_path/cat.aliases/10_basic/Empty cluster");
+        // exact match
+        assertMatch("cat.aliases/10_basic/Empty cluster", "cat.aliases/10_basic/Empty cluster");
+        // additional text at the end should not match
+        assertNoMatch("cat.aliases/10_basic/Empty cluster", "cat.aliases/10_basic/Empty clusters in here");
+    }
+
+    public void testMatchesSimpleWildcardPatterns() {
+        assertMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/test_first");
+        assertMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/");
+        // do not cross segment boundaries
+        assertNoMatch("termvector/20_issue7121/*", "/suite/termvector/20_issue7121/test/first");
+    }
+
+    public void testMatchesMultiWildcardPatterns() {
+        assertMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices");
+        assertMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all");
+        assertNoMatch("indices.get/10_basic/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all/here");
+        assertMatch("indices.get/*/*allow_no_indices*", "/suite/indices.get/10_basic/we_allow_no_indices_at_all");
+        assertMatch("indices.get/*/*allow_no_indices*", "/suite/indices.get/20_basic/we_allow_no_indices_at_all");
+        assertMatch("*/*/*allow_no_indices*", "/suite/path/to/test/indices.get/20_basic/we_allow_no_indices_at_all");
+    }
+
+    public void testMatchesPatternsWithEscapedCommas() {
+        assertMatch("indices.get/10_basic\\,20_advanced/foo", "/suite/indices.get/10_basic,20_advanced/foo");
+    }
+
+    public void testMatchesMixedPatterns() {
+        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/foo");
+        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/my_foo");
+        assertMatch("indices.get/*/10_basic\\,20_advanced/*foo*", "/suite/indices.get/all/10_basic,20_advanced/foo_bar");
+    }
+
+    private void assertMatch(String pattern, String path) {
+        DenylistedPathPatternMatcher matcher = new DenylistedPathPatternMatcher(pattern);
+        assertTrue("Pattern [" + pattern + "] should have matched path [" + path + "]", matcher.isSuffixMatch(path));
+    }
+
+    private void assertNoMatch(String pattern, String path) {
+        DenylistedPathPatternMatcher matcher = new DenylistedPathPatternMatcher(pattern);
+        assertFalse("Pattern [" + pattern + "] should not have matched path [" + path + "]", matcher.isSuffixMatch(path));
+    }
+}
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/ObjectPathTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/ObjectPathTests.java
index 3265d635ee31c..ca07e39719e23 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/ObjectPathTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/ObjectPathTests.java
@@ -31,10 +31,9 @@
 
 package org.opensearch.test.rest.yaml;
 
-import org.opensearch.common.bytes.BytesReference;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
@@ -56,7 +55,7 @@ public class ObjectPathTests extends OpenSearchTestCase {
 
     private static XContentBuilder randomXContentBuilder() throws IOException {
         XContentType xContentType = randomFrom(XContentType.values());
-        return XContentBuilder.builder(XContentFactory.xContent(xContentType));
+        return XContentBuilder.builder(xContentType.xContent());
     }
 
     public void testEvaluateObjectPathEscape() throws Exception {
@@ -342,7 +341,7 @@ public void testEvaluateArrayAsRoot() throws Exception {
         xContentBuilder.endObject();
         xContentBuilder.endArray();
         ObjectPath objectPath = ObjectPath.createFromXContent(
-            XContentFactory.xContent(xContentBuilder.contentType()),
+            xContentBuilder.contentType().xContent(),
             BytesReference.bytes(xContentBuilder)
         );
         Object object = objectPath.evaluate("");
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCaseTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCaseTests.java
index f69e2e3a6baad..3541ec35d6e67 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCaseTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/OpenSearchClientYamlSuiteTestCaseTests.java
@@ -31,13 +31,13 @@
 
 package org.opensearch.test.rest.yaml;
 
+import org.opensearch.test.OpenSearchTestCase;
+
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Map;
 import java.util.Set;
 
-import org.opensearch.test.OpenSearchTestCase;
-
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.Matchers.greaterThan;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParserFailingTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParserFailingTests.java
index 0bee66819d1df..97c69a102345f 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParserFailingTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiParserFailingTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.test.rest.yaml.restspec;
 
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static org.hamcrest.Matchers.containsString;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiTests.java
index 428ee4d826b1e..0f1955f7eeadb 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/restspec/ClientYamlSuiteRestApiTests.java
@@ -32,8 +32,8 @@
 package org.opensearch.test.rest.yaml.restspec;
 
 import org.opensearch.common.util.set.Sets;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/AbstractClientYamlTestFragmentParserTestCase.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/AbstractClientYamlTestFragmentParserTestCase.java
index ffe996342414d..d554e84cb5c04 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/AbstractClientYamlTestFragmentParserTestCase.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/AbstractClientYamlTestFragmentParserTestCase.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.xcontent.NamedXContentRegistry;
-import org.opensearch.common.xcontent.XContentParser;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.junit.After;
 
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSectionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSectionTests.java
index e254d272226ce..ee355e307345c 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSectionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSectionTests.java
@@ -33,9 +33,9 @@
 package org.opensearch.test.rest.yaml.section;
 
 import org.opensearch.LegacyESVersion;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuiteTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuiteTests.java
index fc4564ce55df7..e1c11315cf501 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuiteTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/ClientYamlTestSuiteTests.java
@@ -32,12 +32,10 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.LegacyESVersion;
-import org.opensearch.Version;
 import org.opensearch.client.NodeSelector;
-import org.opensearch.common.ParsingException;
-import org.opensearch.common.xcontent.XContentLocation;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentLocation;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -76,23 +74,9 @@ public void testParseTestSetupTeardownAndSections() throws Exception {
                 + "      indices.get_mapping:\n"
                 + "        index: test_index\n"
                 + "\n"
-                + "  - match: {test_index.test_type.properties.text.type:     string}\n"
-                + "  - match: {test_index.test_type.properties.text.analyzer: whitespace}\n"
+                + "  - match: {test_index.properties.text.type:     string}\n"
+                + "  - match: {test_index.properties.text.analyzer: whitespace}\n"
                 + "\n"
-                + "---\n"
-                + "\"Get type mapping - pre 6.0\":\n"
-                + "\n"
-                + "  - skip:\n"
-                + "      version:     \"6.0.0 - \"\n"
-                + "      reason:      \"for newer versions the index name is always returned\"\n"
-                + "\n"
-                + "  - do:\n"
-                + "      indices.get_mapping:\n"
-                + "        index: test_index\n"
-                + "        type: test_type\n"
-                + "\n"
-                + "  - match: {test_type.properties.text.type:     string}\n"
-                + "  - match: {test_type.properties.text.analyzer: whitespace}\n"
         );
 
         ClientYamlTestSuite restTestSuite = ClientYamlTestSuite.parse(getTestClass().getName(), getTestName(), parser);
@@ -135,7 +119,7 @@ public void testParseTestSetupTeardownAndSections() throws Exception {
             assertThat(restTestSuite.getTeardownSection().isEmpty(), equalTo(true));
         }
 
-        assertThat(restTestSuite.getTestSections().size(), equalTo(2));
+        assertThat(restTestSuite.getTestSections().size(), equalTo(1));
 
         assertThat(restTestSuite.getTestSections().get(0).getName(), equalTo("Get index mapping"));
         assertThat(restTestSuite.getTestSections().get(0).getSkipSection().isEmpty(), equalTo(true));
@@ -147,36 +131,13 @@ public void testParseTestSetupTeardownAndSections() throws Exception {
         assertThat(doSection.getApiCallSection().getParams().get("index"), equalTo("test_index"));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(1), instanceOf(MatchAssertion.class));
         MatchAssertion matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(1);
-        assertThat(matchAssertion.getField(), equalTo("test_index.test_type.properties.text.type"));
+        assertThat(matchAssertion.getField(), equalTo("test_index.properties.text.type"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("string"));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(2), instanceOf(MatchAssertion.class));
         matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(2);
-        assertThat(matchAssertion.getField(), equalTo("test_index.test_type.properties.text.analyzer"));
+        assertThat(matchAssertion.getField(), equalTo("test_index.properties.text.analyzer"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("whitespace"));
 
-        assertThat(restTestSuite.getTestSections().get(1).getName(), equalTo("Get type mapping - pre 6.0"));
-        assertThat(restTestSuite.getTestSections().get(1).getSkipSection().isEmpty(), equalTo(false));
-        assertThat(
-            restTestSuite.getTestSections().get(1).getSkipSection().getReason(),
-            equalTo("for newer versions the index name is always returned")
-        );
-        assertThat(restTestSuite.getTestSections().get(1).getSkipSection().getLowerVersion(), equalTo(LegacyESVersion.fromString("6.0.0")));
-        assertThat(restTestSuite.getTestSections().get(1).getSkipSection().getUpperVersion(), equalTo(Version.CURRENT));
-        assertThat(restTestSuite.getTestSections().get(1).getExecutableSections().size(), equalTo(3));
-        assertThat(restTestSuite.getTestSections().get(1).getExecutableSections().get(0), instanceOf(DoSection.class));
-        doSection = (DoSection) restTestSuite.getTestSections().get(1).getExecutableSections().get(0);
-        assertThat(doSection.getApiCallSection().getApi(), equalTo("indices.get_mapping"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
-        assertThat(doSection.getApiCallSection().getParams().get("index"), equalTo("test_index"));
-        assertThat(doSection.getApiCallSection().getParams().get("type"), equalTo("test_type"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(1), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(1).getExecutableSections().get(1);
-        assertThat(matchAssertion.getField(), equalTo("test_type.properties.text.type"));
-        assertThat(matchAssertion.getExpectedValue().toString(), equalTo("string"));
-        assertThat(restTestSuite.getTestSections().get(1).getExecutableSections().get(2), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(1).getExecutableSections().get(2);
-        assertThat(matchAssertion.getField(), equalTo("test_type.properties.text.analyzer"));
-        assertThat(matchAssertion.getExpectedValue().toString(), equalTo("whitespace"));
     }
 
     public void testParseTestSingleTestSection() throws Exception {
@@ -188,24 +149,20 @@ public void testParseTestSingleTestSection() throws Exception {
                 + " - do:\n"
                 + "      index:\n"
                 + "          index:  test-weird-index-中文\n"
-                + "          type:   weird.type\n"
                 + "          id:     1\n"
                 + "          body:   { foo: bar }\n"
                 + "\n"
                 + " - is_true:   ok\n"
                 + " - match:   { _index:   test-weird-index-中文 }\n"
-                + " - match:   { _type:    weird.type }\n"
                 + " - match:   { _id:      \"1\"}\n"
                 + " - match:   { _version: 1}\n"
                 + "\n"
                 + " - do:\n"
                 + "      get:\n"
                 + "          index:  test-weird-index-中文\n"
-                + "          type:   weird.type\n"
                 + "          id:     1\n"
                 + "\n"
                 + " - match:   { _index:   test-weird-index-中文 }\n"
-                + " - match:   { _type:    weird.type }\n"
                 + " - match:   { _id:      \"1\"}\n"
                 + " - match:   { _version: 1}\n"
                 + " - match:   { _source: { foo: bar }}"
@@ -222,12 +179,12 @@ public void testParseTestSingleTestSection() throws Exception {
 
         assertThat(restTestSuite.getTestSections().get(0).getName(), equalTo("Index with ID"));
         assertThat(restTestSuite.getTestSections().get(0).getSkipSection().isEmpty(), equalTo(true));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().size(), equalTo(12));
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().size(), equalTo(10));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(0), instanceOf(DoSection.class));
         DoSection doSection = (DoSection) restTestSuite.getTestSections().get(0).getExecutableSections().get(0);
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("index"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(true));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(1), instanceOf(IsTrueAssertion.class));
         IsTrueAssertion trueAssertion = (IsTrueAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(1);
@@ -238,40 +195,32 @@ public void testParseTestSingleTestSection() throws Exception {
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("test-weird-index-中文"));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(3), instanceOf(MatchAssertion.class));
         matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(3);
-        assertThat(matchAssertion.getField(), equalTo("_type"));
-        assertThat(matchAssertion.getExpectedValue().toString(), equalTo("weird.type"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(4), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(4);
         assertThat(matchAssertion.getField(), equalTo("_id"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("1"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(5), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(5);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(4), instanceOf(MatchAssertion.class));
+        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(4);
         assertThat(matchAssertion.getField(), equalTo("_version"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("1"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(6), instanceOf(DoSection.class));
-        doSection = (DoSection) restTestSuite.getTestSections().get(0).getExecutableSections().get(6);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(5), instanceOf(DoSection.class));
+        doSection = (DoSection) restTestSuite.getTestSections().get(0).getExecutableSections().get(5);
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("get"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(false));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(7), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(7);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(6), instanceOf(MatchAssertion.class));
+        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(6);
         assertThat(matchAssertion.getField(), equalTo("_index"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("test-weird-index-中文"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(8), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(8);
-        assertThat(matchAssertion.getField(), equalTo("_type"));
-        assertThat(matchAssertion.getExpectedValue().toString(), equalTo("weird.type"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(9), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(9);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(7), instanceOf(MatchAssertion.class));
+        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(7);
         assertThat(matchAssertion.getField(), equalTo("_id"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("1"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(10), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(10);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(8), instanceOf(MatchAssertion.class));
+        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(8);
         assertThat(matchAssertion.getField(), equalTo("_version"));
         assertThat(matchAssertion.getExpectedValue().toString(), equalTo("1"));
-        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(11), instanceOf(MatchAssertion.class));
-        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(11);
+        assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(9), instanceOf(MatchAssertion.class));
+        matchAssertion = (MatchAssertion) restTestSuite.getTestSections().get(0).getExecutableSections().get(9);
         assertThat(matchAssertion.getField(), equalTo("_source"));
         assertThat(matchAssertion.getExpectedValue(), instanceOf(Map.class));
         assertThat(((Map) matchAssertion.getExpectedValue()).get("foo").toString(), equalTo("bar"));
@@ -287,14 +236,12 @@ public void testParseTestMultipleTestSections() throws Exception {
                 + "      catch:      missing\n"
                 + "      update:\n"
                 + "          index:  test_1\n"
-                + "          type:   test\n"
                 + "          id:     1\n"
                 + "          body:   { doc: { foo: bar } }\n"
                 + "\n"
                 + "  - do:\n"
                 + "      update:\n"
                 + "          index: test_1\n"
-                + "          type:  test\n"
                 + "          id:    1\n"
                 + "          body:  { doc: { foo: bar } }\n"
                 + "          ignore: 404\n"
@@ -307,7 +254,6 @@ public void testParseTestMultipleTestSections() throws Exception {
                 + "      catch:      missing\n"
                 + "      update:\n"
                 + "          index:  test_1\n"
-                + "          type:   test\n"
                 + "          id:     1\n"
                 + "          body:\n"
                 + "            script: \"ctx._source.foo = bar\"\n"
@@ -316,7 +262,6 @@ public void testParseTestMultipleTestSections() throws Exception {
                 + "  - do:\n"
                 + "      update:\n"
                 + "          index:  test_1\n"
-                + "          type:   test\n"
                 + "          id:     1\n"
                 + "          ignore: 404\n"
                 + "          body:\n"
@@ -341,13 +286,13 @@ public void testParseTestMultipleTestSections() throws Exception {
         DoSection doSection = (DoSection) restTestSuite.getTestSections().get(0).getExecutableSections().get(0);
         assertThat(doSection.getCatch(), equalTo("missing"));
         assertThat(doSection.getApiCallSection().getApi(), equalTo("update"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(true));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(1), instanceOf(DoSection.class));
         doSection = (DoSection) restTestSuite.getTestSections().get(0).getExecutableSections().get(1);
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("update"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(4));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(true));
 
         assertThat(restTestSuite.getTestSections().get(1).getName(), equalTo("Missing document (script)"));
@@ -358,13 +303,13 @@ public void testParseTestMultipleTestSections() throws Exception {
         doSection = (DoSection) restTestSuite.getTestSections().get(1).getExecutableSections().get(0);
         assertThat(doSection.getCatch(), equalTo("missing"));
         assertThat(doSection.getApiCallSection().getApi(), equalTo("update"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(true));
         assertThat(restTestSuite.getTestSections().get(0).getExecutableSections().get(1), instanceOf(DoSection.class));
         doSection = (DoSection) restTestSuite.getTestSections().get(1).getExecutableSections().get(1);
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("update"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(4));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(true));
     }
 
@@ -378,7 +323,6 @@ public void testParseTestDuplicateTestSections() throws Exception {
                 + "      catch:      missing\n"
                 + "      update:\n"
                 + "          index:  test_1\n"
-                + "          type:   test\n"
                 + "          id:     1\n"
                 + "          body:   { doc: { foo: bar } }\n"
                 + "\n"
@@ -390,7 +334,6 @@ public void testParseTestDuplicateTestSections() throws Exception {
                 + "      catch:      missing\n"
                 + "      update:\n"
                 + "          index:  test_1\n"
-                + "          type:   test\n"
                 + "          id:     1\n"
                 + "          body:\n"
                 + "            script: \"ctx._source.foo = bar\"\n"
@@ -486,7 +429,7 @@ public void testAddingDoWithNodeSelectorWithoutSkipNodeSelector() {
         int lineNumber = between(1, 10000);
         DoSection doSection = new DoSection(new XContentLocation(lineNumber, 0));
         ApiCallSection apiCall = new ApiCallSection("test");
-        apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_MASTERS);
+        apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS);
         doSection.setApiCallSection(apiCall);
         ClientYamlTestSuite testSuite = createTestSuite(SkipSection.EMPTY, doSection);
         Exception e = expectThrows(IllegalArgumentException.class, testSuite::validate);
@@ -553,7 +496,7 @@ public void testMultipleValidationErrors() {
         {
             DoSection doSection = new DoSection(new XContentLocation(thirdLineNumber, 0));
             ApiCallSection apiCall = new ApiCallSection("test");
-            apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_MASTERS);
+            apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS);
             doSection.setApiCallSection(apiCall);
             doSections.add(doSection);
         }
@@ -593,7 +536,7 @@ public void testAddingDoWithNodeSelectorWithSkip() {
         SkipSection skipSection = new SkipSection(null, singletonList("node_selector"), null);
         DoSection doSection = new DoSection(new XContentLocation(lineNumber, 0));
         ApiCallSection apiCall = new ApiCallSection("test");
-        apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_MASTERS);
+        apiCall.setNodeSelector(NodeSelector.SKIP_DEDICATED_CLUSTER_MANAGERS);
         doSection.setApiCallSection(apiCall);
         createTestSuite(skipSection, doSection).validate();
     }
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/DoSectionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/DoSectionTests.java
index 53cae686e3cac..c03e114596fc6 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/DoSectionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/DoSectionTests.java
@@ -36,11 +36,11 @@
 import org.opensearch.Version;
 import org.opensearch.client.Node;
 import org.opensearch.client.NodeSelector;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.logging.HeaderWarning;
-import org.opensearch.common.xcontent.XContentLocation;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
+import org.opensearch.core.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 import org.opensearch.test.rest.yaml.ClientYamlTestResponse;
 import org.hamcrest.MatcherAssert;
@@ -173,19 +173,15 @@ public void testIgnoreTypesWarnings() {
     }
 
     public void testParseDoSectionNoBody() throws Exception {
-        parser = createParser(
-            YamlXContent.yamlXContent,
-            "get:\n" + "    index:    test_index\n" + "    type:    test_type\n" + "    id:        1"
-        );
+        parser = createParser(YamlXContent.yamlXContent, "get:\n" + "    index:    test_index\n" + "    id:        1");
 
         DoSection doSection = DoSection.parse(parser);
         ApiCallSection apiCallSection = doSection.getApiCallSection();
 
         assertThat(apiCallSection, notNullValue());
         assertThat(apiCallSection.getApi(), equalTo("get"));
-        assertThat(apiCallSection.getParams().size(), equalTo(3));
+        assertThat(apiCallSection.getParams().size(), equalTo(2));
         assertThat(apiCallSection.getParams().get("index"), equalTo("test_index"));
-        assertThat(apiCallSection.getParams().get("type"), equalTo("test_type"));
         assertThat(apiCallSection.getParams().get("id"), equalTo("1"));
         assertThat(apiCallSection.hasBody(), equalTo(false));
     }
@@ -204,19 +200,15 @@ public void testParseDoSectionNoParamsNoBody() throws Exception {
 
     public void testParseDoSectionWithJsonBody() throws Exception {
         String body = "{ \"include\": { \"field1\": \"v1\", \"field2\": \"v2\" }, \"count\": 1 }";
-        parser = createParser(
-            YamlXContent.yamlXContent,
-            "index:\n" + "    index:  test_1\n" + "    type:   test\n" + "    id:     1\n" + "    body:   " + body
-        );
+        parser = createParser(YamlXContent.yamlXContent, "index:\n" + "    index:  test_1\n" + "    id:     1\n" + "    body:   " + body);
 
         DoSection doSection = DoSection.parse(parser);
         ApiCallSection apiCallSection = doSection.getApiCallSection();
 
         assertThat(apiCallSection, notNullValue());
         assertThat(apiCallSection.getApi(), equalTo("index"));
-        assertThat(apiCallSection.getParams().size(), equalTo(3));
+        assertThat(apiCallSection.getParams().size(), equalTo(2));
         assertThat(apiCallSection.getParams().get("index"), equalTo("test_1"));
-        assertThat(apiCallSection.getParams().get("type"), equalTo("test"));
         assertThat(apiCallSection.getParams().get("id"), equalTo("1"));
         assertThat(apiCallSection.hasBody(), equalTo(true));
 
@@ -225,9 +217,9 @@ public void testParseDoSectionWithJsonBody() throws Exception {
 
     public void testParseDoSectionWithJsonMultipleBodiesAsLongString() throws Exception {
         String bodies[] = new String[] {
-            "{ \"index\": { \"_index\":\"test_index\", \"_type\":\"test_type\", \"_id\":\"test_id\" } }\n",
+            "{ \"index\": { \"_index\":\"test_index\", \"_id\":\"test_id\" } }\n",
             "{ \"f1\":\"v1\", \"f2\":42 }\n",
-            "{ \"index\": { \"_index\":\"test_index2\", \"_type\":\"test_type2\", \"_id\":\"test_id2\" } }\n",
+            "{ \"index\": { \"_index\":\"test_index2\", \"_id\":\"test_id2\" } }\n",
             "{ \"f1\":\"v2\", \"f2\":47 }\n" };
         parser = createParser(
             YamlXContent.yamlXContent,
@@ -284,21 +276,19 @@ public void testParseDoSectionWithYamlMultipleBodies() throws Exception {
                 + "    body:\n"
                 + "        - index:\n"
                 + "            _index: test_index\n"
-                + "            _type:  test_type\n"
                 + "            _id:    test_id\n"
                 + "        - f1: v1\n"
                 + "          f2: 42\n"
                 + "        - index:\n"
                 + "            _index: test_index2\n"
-                + "            _type:  test_type2\n"
                 + "            _id:    test_id2\n"
                 + "        - f1: v2\n"
                 + "          f2: 47"
         );
         String[] bodies = new String[4];
-        bodies[0] = "{\"index\": {\"_index\": \"test_index\", \"_type\":  \"test_type\", \"_id\": \"test_id\"}}";
+        bodies[0] = "{\"index\": {\"_index\": \"test_index\", \"_id\": \"test_id\"}}";
         bodies[1] = "{ \"f1\":\"v1\", \"f2\": 42 }";
-        bodies[2] = "{\"index\": {\"_index\": \"test_index2\", \"_type\":  \"test_type2\", \"_id\": \"test_id2\"}}";
+        bodies[2] = "{\"index\": {\"_index\": \"test_index2\", \"_id\": \"test_id2\"}}";
         bodies[3] = "{ \"f1\":\"v2\", \"f2\": 47 }";
 
         DoSection doSection = DoSection.parse(parser);
@@ -322,13 +312,10 @@ public void testParseDoSectionWithYamlBodyMultiGet() throws Exception {
             "mget:\n"
                 + "    body:\n"
                 + "        docs:\n"
-                + "            - { _index: test_2, _type: test, _id: 1}\n"
-                + "            - { _index: test_1, _type: none, _id: 1}"
+                + "            - { _index: test_2, _id: 1}\n"
+                + "            - { _index: test_1, _id: 1}"
         );
-        String body = "{ \"docs\": [ "
-            + "{\"_index\": \"test_2\", \"_type\":\"test\", \"_id\":1}, "
-            + "{\"_index\": \"test_1\", \"_type\":\"none\", \"_id\":1} "
-            + "]}";
+        String body = "{ \"docs\": [ " + "{\"_index\": \"test_2\", \"_id\":1}, " + "{\"_index\": \"test_1\", \"_id\":1} " + "]}";
 
         DoSection doSection = DoSection.parse(parser);
         ApiCallSection apiCallSection = doSection.getApiCallSection();
@@ -346,7 +333,6 @@ public void testParseDoSectionWithBodyStringified() throws Exception {
             YamlXContent.yamlXContent,
             "index:\n"
                 + "    index:  test_1\n"
-                + "    type:   test\n"
                 + "    id:     1\n"
                 + "    body:   \"{ \\\"_source\\\": true, \\\"query\\\": { \\\"match_all\\\": {} } }\""
         );
@@ -356,9 +342,8 @@ public void testParseDoSectionWithBodyStringified() throws Exception {
 
         assertThat(apiCallSection, notNullValue());
         assertThat(apiCallSection.getApi(), equalTo("index"));
-        assertThat(apiCallSection.getParams().size(), equalTo(3));
+        assertThat(apiCallSection.getParams().size(), equalTo(2));
         assertThat(apiCallSection.getParams().get("index"), equalTo("test_1"));
-        assertThat(apiCallSection.getParams().get("type"), equalTo("test"));
         assertThat(apiCallSection.getParams().get("id"), equalTo("1"));
         assertThat(apiCallSection.hasBody(), equalTo(true));
         assertThat(apiCallSection.getBodies().size(), equalTo(1));
@@ -444,16 +429,15 @@ public void testParseDoSectionWithoutClientCallSection() throws Exception {
     public void testParseDoSectionMultivaluedField() throws Exception {
         parser = createParser(
             YamlXContent.yamlXContent,
-            "indices.get_field_mapping:\n" + "        index: test_index\n" + "        type: test_type\n" + "        field: [ text , text1 ]"
+            "indices.get_field_mapping:\n" + "        index: test_index\n" + "        field: [ text , text1 ]"
         );
 
         DoSection doSection = DoSection.parse(parser);
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection(), notNullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("indices.get_field_mapping"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(3));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
         assertThat(doSection.getApiCallSection().getParams().get("index"), equalTo("test_index"));
-        assertThat(doSection.getApiCallSection().getParams().get("type"), equalTo("test_type"));
         assertThat(doSection.getApiCallSection().getParams().get("field"), equalTo("text,text1"));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(false));
         assertThat(doSection.getApiCallSection().getBodies().size(), equalTo(0));
@@ -464,7 +448,6 @@ public void testParseDoSectionExpectedWarnings() throws Exception {
             YamlXContent.yamlXContent,
             "indices.get_field_mapping:\n"
                 + "        index: test_index\n"
-                + "        type: test_type\n"
                 + "warnings:\n"
                 + "    - some test warning they are typically pretty long\n"
                 + "    - some other test warning sometimes they have [in] them"
@@ -474,9 +457,8 @@ public void testParseDoSectionExpectedWarnings() throws Exception {
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection(), notNullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("indices.get_field_mapping"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(1));
         assertThat(doSection.getApiCallSection().getParams().get("index"), equalTo("test_index"));
-        assertThat(doSection.getApiCallSection().getParams().get("type"), equalTo("test_type"));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(false));
         assertThat(doSection.getApiCallSection().getBodies().size(), equalTo(0));
         assertThat(
@@ -502,7 +484,6 @@ public void testParseDoSectionAllowedWarnings() throws Exception {
             YamlXContent.yamlXContent,
             "indices.get_field_mapping:\n"
                 + "        index: test_index\n"
-                + "        type: test_type\n"
                 + "allowed_warnings:\n"
                 + "    - some test warning they are typically pretty long\n"
                 + "    - some other test warning sometimes they have [in] them"
@@ -512,9 +493,8 @@ public void testParseDoSectionAllowedWarnings() throws Exception {
         assertThat(doSection.getCatch(), nullValue());
         assertThat(doSection.getApiCallSection(), notNullValue());
         assertThat(doSection.getApiCallSection().getApi(), equalTo("indices.get_field_mapping"));
-        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(2));
+        assertThat(doSection.getApiCallSection().getParams().size(), equalTo(1));
         assertThat(doSection.getApiCallSection().getParams().get("index"), equalTo("test_index"));
-        assertThat(doSection.getApiCallSection().getParams().get("type"), equalTo("test_type"));
         assertThat(doSection.getApiCallSection().hasBody(), equalTo(false));
         assertThat(doSection.getApiCallSection().getBodies().size(), equalTo(0));
         assertThat(
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/MatchAssertionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/MatchAssertionTests.java
index 15887ed2acada..131fc6a80b584 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/MatchAssertionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/MatchAssertionTests.java
@@ -31,7 +31,7 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.xcontent.XContentLocation;
+import org.opensearch.core.xcontent.XContentLocation;
 import org.opensearch.test.OpenSearchTestCase;
 
 import static java.util.Collections.emptyMap;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SetSectionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SetSectionTests.java
index c82694f23aa1b..4e0cc8da17f80 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SetSectionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SetSectionTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SkipSectionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SkipSectionTests.java
index 2735128a4583d..c766d8f3ca734 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SkipSectionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/SkipSectionTests.java
@@ -34,8 +34,8 @@
 
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.VersionUtils;
 
 import java.util.Collections;
diff --git a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/TransformAndSetSectionTests.java b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/TransformAndSetSectionTests.java
index 4eb51d8c6f9bb..4ed27e8bad681 100644
--- a/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/TransformAndSetSectionTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/rest/yaml/section/TransformAndSetSectionTests.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test.rest.yaml.section;
 
-import org.opensearch.common.ParsingException;
 import org.opensearch.common.xcontent.yaml.YamlXContent;
+import org.opensearch.core.common.ParsingException;
 import org.opensearch.test.rest.yaml.ClientYamlTestExecutionContext;
 import org.opensearch.test.rest.yaml.Stash;
 
diff --git a/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterIT.java b/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterIT.java
index b650eb2c03022..20f054f593e78 100644
--- a/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterIT.java
+++ b/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterIT.java
@@ -33,9 +33,9 @@
 
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
-import org.opensearch.test.InternalTestCluster;
 
 import java.io.IOException;
 
@@ -79,7 +79,7 @@ public void testStoppingNodesOneByOne() throws IOException {
     }
 
     public void testOperationsDuringRestart() throws Exception {
-        internalCluster().startMasterOnlyNode();
+        internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNodes(2);
         internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
             @Override
diff --git a/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterTests.java b/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterTests.java
index f1aee04d92a19..1d9f7920dae35 100644
--- a/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/test/InternalTestClusterTests.java
@@ -38,17 +38,17 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.core.internal.io.IOUtils;
+import org.opensearch.common.util.io.IOUtils;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.discovery.SettingsBasedSeedHostsProvider;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.node.Node.DiscoverySettings;
 import org.opensearch.plugins.Plugin;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.InternalTestCluster;
 import org.opensearch.test.MockHttpTransport;
 import org.opensearch.test.NodeConfigurationSource;
+import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -86,7 +86,7 @@ private static Collection<Class<? extends Plugin>> mockPlugins() {
 
     public void testInitializiationIsConsistent() {
         long clusterSeed = randomLong();
-        boolean masterNodes = randomBoolean();
+        boolean clusterManagerNodes = randomBoolean();
         int minNumDataNodes = randomIntBetween(0, 9);
         int maxNumDataNodes = randomIntBetween(minNumDataNodes, 10);
         String clusterName = randomRealisticUnicodeOfCodepointLengthBetween(1, 10);
@@ -98,7 +98,7 @@ public void testInitializiationIsConsistent() {
         InternalTestCluster cluster0 = new InternalTestCluster(
             clusterSeed,
             baseDir,
-            masterNodes,
+            clusterManagerNodes,
             randomBoolean(),
             minNumDataNodes,
             maxNumDataNodes,
@@ -112,7 +112,7 @@ public void testInitializiationIsConsistent() {
         InternalTestCluster cluster1 = new InternalTestCluster(
             clusterSeed,
             baseDir,
-            masterNodes,
+            clusterManagerNodes,
             randomBoolean(),
             minNumDataNodes,
             maxNumDataNodes,
@@ -165,23 +165,23 @@ public static void assertSettings(Settings left, Settings right, boolean checkCl
     }
 
     public void testBeforeTest() throws Exception {
-        final boolean autoManageMinMasterNodes = randomBoolean();
+        final boolean autoManageMinClusterManagerNodes = randomBoolean();
         long clusterSeed = randomLong();
-        final boolean masterNodes;
+        final boolean clusterManagerNodes;
         final int minNumDataNodes;
         final int maxNumDataNodes;
-        final int bootstrapMasterNodeIndex;
-        if (autoManageMinMasterNodes) {
-            masterNodes = randomBoolean();
+        final int bootstrapClusterManagerNodeIndex;
+        if (autoManageMinClusterManagerNodes) {
+            clusterManagerNodes = randomBoolean();
             minNumDataNodes = randomIntBetween(0, 3);
             maxNumDataNodes = randomIntBetween(minNumDataNodes, 4);
-            bootstrapMasterNodeIndex = -1;
+            bootstrapClusterManagerNodeIndex = -1;
         } else {
-            // if we manage min master nodes, we need to lock down the number of nodes
+            // if we manage min cluster-manager nodes, we need to lock down the number of nodes
             minNumDataNodes = randomIntBetween(0, 4);
             maxNumDataNodes = minNumDataNodes;
-            masterNodes = false;
-            bootstrapMasterNodeIndex = maxNumDataNodes == 0 ? -1 : randomIntBetween(0, maxNumDataNodes - 1);
+            clusterManagerNodes = false;
+            bootstrapClusterManagerNodeIndex = maxNumDataNodes == 0 ? -1 : randomIntBetween(0, maxNumDataNodes - 1);
         }
         final int numClientNodes = randomIntBetween(0, 2);
         NodeConfigurationSource nodeConfigurationSource = new NodeConfigurationSource() {
@@ -191,9 +191,9 @@ public Settings nodeSettings(int nodeOrdinal) {
                     .put(DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING.getKey(), "file")
                     .putList(SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING.getKey())
                     .put(NetworkModule.TRANSPORT_TYPE_KEY, getTestTransportType());
-                if (autoManageMinMasterNodes == false) {
+                if (autoManageMinClusterManagerNodes == false) {
                     assert minNumDataNodes == maxNumDataNodes;
-                    assert masterNodes == false;
+                    assert clusterManagerNodes == false;
                 }
                 return settings.build();
             }
@@ -209,8 +209,8 @@ public Path nodeConfigPath(int nodeOrdinal) {
         InternalTestCluster cluster0 = new InternalTestCluster(
             clusterSeed,
             createTempDir(),
-            masterNodes,
-            autoManageMinMasterNodes,
+            clusterManagerNodes,
+            autoManageMinClusterManagerNodes,
             minNumDataNodes,
             maxNumDataNodes,
             "clustername",
@@ -220,13 +220,13 @@ public Path nodeConfigPath(int nodeOrdinal) {
             mockPlugins(),
             Function.identity()
         );
-        cluster0.setBootstrapMasterNodeIndex(bootstrapMasterNodeIndex);
+        cluster0.setBootstrapClusterManagerNodeIndex(bootstrapClusterManagerNodeIndex);
 
         InternalTestCluster cluster1 = new InternalTestCluster(
             clusterSeed,
             createTempDir(),
-            masterNodes,
-            autoManageMinMasterNodes,
+            clusterManagerNodes,
+            autoManageMinClusterManagerNodes,
             minNumDataNodes,
             maxNumDataNodes,
             "clustername",
@@ -236,7 +236,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
             mockPlugins(),
             Function.identity()
         );
-        cluster1.setBootstrapMasterNodeIndex(bootstrapMasterNodeIndex);
+        cluster1.setBootstrapClusterManagerNodeIndex(bootstrapClusterManagerNodeIndex);
 
         assertClusters(cluster0, cluster1, false);
         long seed = randomLong();
@@ -265,7 +265,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
 
     public void testDataFolderAssignmentAndCleaning() throws IOException, InterruptedException {
         long clusterSeed = randomLong();
-        boolean masterNodes = randomBoolean();
+        boolean clusterManagerNodes = randomBoolean();
         // we need one stable node
         final int minNumDataNodes = 2;
         final int maxNumDataNodes = 2;
@@ -291,7 +291,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
         InternalTestCluster cluster = new InternalTestCluster(
             clusterSeed,
             baseDir,
-            masterNodes,
+            clusterManagerNodes,
             true,
             minNumDataNodes,
             maxNumDataNodes,
@@ -304,13 +304,13 @@ public Path nodeConfigPath(int nodeOrdinal) {
         );
         try {
             cluster.beforeTest(random());
-            final int originalMasterCount = cluster.numMasterNodes();
+            final int originalClusterManagerCount = cluster.numClusterManagerNodes();
             final Map<String, Path[]> shardNodePaths = new HashMap<>();
             for (String name : cluster.getNodeNames()) {
                 shardNodePaths.put(name, getNodePaths(cluster, name));
             }
             String poorNode = randomValueOtherThanMany(
-                n -> originalMasterCount == 1 && n.equals(cluster.getMasterName()),
+                n -> originalClusterManagerCount == 1 && n.equals(cluster.getClusterManagerName()),
                 () -> randomFrom(cluster.getNodeNames())
             );
             Path dataPath = getNodePaths(cluster, poorNode)[0];
@@ -404,12 +404,12 @@ public Path nodeConfigPath(int nodeOrdinal) {
         List<DiscoveryNodeRole> roles = new ArrayList<>();
         for (int i = 0; i < numNodes; i++) {
             final DiscoveryNodeRole role = i == numNodes - 1 && roles.contains(clusterManagerRole) == false
-                ? clusterManagerRole  // last node and still no master
+                ? clusterManagerRole  // last node and still no cluster-manager
                 : randomFrom(clusterManagerRole, DiscoveryNodeRole.DATA_ROLE, DiscoveryNodeRole.INGEST_ROLE);
             roles.add(role);
         }
 
-        cluster.setBootstrapMasterNodeIndex(
+        cluster.setBootstrapClusterManagerNodeIndex(
             randomIntBetween(0, (int) roles.stream().filter(role -> role.equals(clusterManagerRole)).count() - 1)
         );
 
@@ -419,7 +419,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
                 final DiscoveryNodeRole role = roles.get(i);
                 final String node;
                 if (role == clusterManagerRole) {
-                    node = cluster.startMasterOnlyNode();
+                    node = cluster.startClusterManagerOnlyNode();
                 } else if (role == DiscoveryNodeRole.DATA_ROLE) {
                     node = cluster.startDataOnlyNode();
                 } else if (role == DiscoveryNodeRole.INGEST_ROLE) {
@@ -439,7 +439,7 @@ public Path nodeConfigPath(int nodeOrdinal) {
             for (String name : cluster.getNodeNames()) {
                 DiscoveryNode node = cluster.getInstance(ClusterService.class, name).localNode();
                 List<String> paths = Arrays.stream(getNodePaths(cluster, name)).map(Path::toString).collect(Collectors.toList());
-                if (node.isMasterNode()) {
+                if (node.isClusterManagerNode()) {
                     result.computeIfAbsent(clusterManagerRole, k -> new HashSet<>()).addAll(paths);
                 } else if (node.isDataNode()) {
                     result.computeIfAbsent(DiscoveryNodeRole.DATA_ROLE, k -> new HashSet<>()).addAll(paths);
diff --git a/test/framework/src/test/java/org/opensearch/test/test/OpenSearchTestCaseTests.java b/test/framework/src/test/java/org/opensearch/test/test/OpenSearchTestCaseTests.java
index b2ad2e51ec8a3..18b0d1f719b5f 100644
--- a/test/framework/src/test/java/org/opensearch/test/test/OpenSearchTestCaseTests.java
+++ b/test/framework/src/test/java/org/opensearch/test/test/OpenSearchTestCaseTests.java
@@ -32,13 +32,11 @@
 
 package org.opensearch.test.test;
 
-import junit.framework.AssertionFailedError;
-
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.time.DateFormatter;
-import org.opensearch.common.xcontent.XContentBuilder;
-import org.opensearch.common.xcontent.XContentParser;
 import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.core.common.bytes.BytesReference;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.RandomObjects;
 
@@ -54,6 +52,8 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Supplier;
 
+import junit.framework.AssertionFailedError;
+
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.hasSize;
diff --git a/test/framework/src/test/java/org/opensearch/test/test/SuiteScopeClusterIT.java b/test/framework/src/test/java/org/opensearch/test/test/SuiteScopeClusterIT.java
index 4d8bc2e9f0ffc..5c0f311e056c2 100644
--- a/test/framework/src/test/java/org/opensearch/test/test/SuiteScopeClusterIT.java
+++ b/test/framework/src/test/java/org/opensearch/test/test/SuiteScopeClusterIT.java
@@ -32,6 +32,7 @@
 package org.opensearch.test.test;
 
 import com.carrotsearch.randomizedtesting.annotations.Repeat;
+
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.test.OpenSearchIntegTestCase;
 import org.opensearch.test.TestCluster;
diff --git a/test/framework/src/test/java/org/opensearch/transport/nio/SimpleMockNioTransportTests.java b/test/framework/src/test/java/org/opensearch/transport/nio/SimpleMockNioTransportTests.java
index e42c7e6fc4f85..ce401ad99fad7 100644
--- a/test/framework/src/test/java/org/opensearch/transport/nio/SimpleMockNioTransportTests.java
+++ b/test/framework/src/test/java/org/opensearch/transport/nio/SimpleMockNioTransportTests.java
@@ -33,15 +33,16 @@
 package org.opensearch.transport.nio;
 
 import org.opensearch.Version;
-import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.MockPageCacheRecycler;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.telemetry.tracing.noop.NoopTracer;
 import org.opensearch.transport.AbstractSimpleTransportTestCase;
 import org.opensearch.transport.ConnectTransportException;
 import org.opensearch.transport.ConnectionProfile;
@@ -71,7 +72,8 @@ protected Transport build(Settings settings, final Version version, ClusterSetti
             networkService,
             new MockPageCacheRecycler(settings),
             namedWriteableRegistry,
-            new NoneCircuitBreakerService()
+            new NoneCircuitBreakerService(),
+            NoopTracer.INSTANCE
         ) {
 
             @Override
diff --git a/test/framework/src/test/java/org/opensearch/transport/nio/TestEventHandlerTests.java b/test/framework/src/test/java/org/opensearch/transport/nio/TestEventHandlerTests.java
index bbbc7ea7f53b3..0492d56f9df77 100644
--- a/test/framework/src/test/java/org/opensearch/transport/nio/TestEventHandlerTests.java
+++ b/test/framework/src/test/java/org/opensearch/transport/nio/TestEventHandlerTests.java
@@ -38,8 +38,8 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.nio.ServerChannelContext;
 import org.opensearch.nio.SocketChannelContext;
-import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.test.MockLogAppender;
+import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.threadpool.ThreadPool;
 
 import java.util.HashMap;
diff --git a/test/framework/src/test/resources/rest-api-spec/test/suite1/10_basic.yml b/test/framework/src/test/resources/rest-api-spec/test/suite1/10_basic.yml
index 0689f714d6416..c5fde76e94cc2 100644
--- a/test/framework/src/test/resources/rest-api-spec/test/suite1/10_basic.yml
+++ b/test/framework/src/test/resources/rest-api-spec/test/suite1/10_basic.yml
@@ -4,18 +4,15 @@
   - do:
       index:
         index: test_1
-        type:  test
         id:    中文
         body:  { "foo": "Hello: 中文" }
 
   - do:
       get:
         index: test_1
-        type:  test
         id:    中文
 
   - match: { _index:   test_1 }
-  - match: { _type:    test   }
   - match: { _id:      中文      }
   - match: { _source:  { foo: "Hello: 中文" } }
 
@@ -26,6 +23,5 @@
         id:    中文
 
   - match: { _index:   test_1 }
-  - match: { _type:    test   }
   - match: { _id:      中文      }
   - match: { _source:  { foo: "Hello: 中文" } }
diff --git a/test/framework/src/test/resources/rest-api-spec/test/suite1/20_another_test.yml b/test/framework/src/test/resources/rest-api-spec/test/suite1/20_another_test.yml
index 5e08112253ef0..0d27f91a83dd3 100644
--- a/test/framework/src/test/resources/rest-api-spec/test/suite1/20_another_test.yml
+++ b/test/framework/src/test/resources/rest-api-spec/test/suite1/20_another_test.yml
@@ -18,4 +18,3 @@
   - match: { _type:    test   }
   - match: { _id:      '1'    }
   - match: { _source:  { foo: "bar" } }
-
diff --git a/test/logger-usage/build.gradle b/test/logger-usage/build.gradle
index ecfccc9338410..e81cdef04df1f 100644
--- a/test/logger-usage/build.gradle
+++ b/test/logger-usage/build.gradle
@@ -31,9 +31,9 @@
 apply plugin: 'opensearch.java'
 
 dependencies {
-  api 'org.ow2.asm:asm:9.2'
-  api 'org.ow2.asm:asm-tree:9.2'
-  api 'org.ow2.asm:asm-analysis:9.2'
+  api "org.ow2.asm:asm:${versions.asm}"
+  api "org.ow2.asm:asm-tree:${versions.asm}"
+  api "org.ow2.asm:asm-analysis:${versions.asm}"
   api "org.apache.logging.log4j:log4j-api:${versions.log4j}"
   testImplementation project(":test:framework")
 }
diff --git a/test/logger-usage/src/test/java/org/opensearch/test/loggerusage/OpenSearchLoggerUsageTests.java b/test/logger-usage/src/test/java/org/opensearch/test/loggerusage/OpenSearchLoggerUsageTests.java
index e9723c269763c..3bbc8100955f3 100644
--- a/test/logger-usage/src/test/java/org/opensearch/test/loggerusage/OpenSearchLoggerUsageTests.java
+++ b/test/logger-usage/src/test/java/org/opensearch/test/loggerusage/OpenSearchLoggerUsageTests.java
@@ -79,31 +79,32 @@ public void testLoggerUsageChecks() throws IOException {
         }
     }
 
-    public void testLoggerUsageCheckerCompatibilityWithLog4j2Logger() throws NoSuchMethodException {
+    public void testLoggerUsageCheckerCompatibilityWithLog4j2Logger() {
         for (Method method : Logger.class.getMethods()) {
             if (OpenSearchLoggerUsageChecker.LOGGER_METHODS.contains(method.getName())) {
-                assertThat(method.getParameterTypes().length, greaterThanOrEqualTo(1));
-                int markerOffset = method.getParameterTypes()[0].equals(Marker.class) ? 1 : 0;
-                int paramLength = method.getParameterTypes().length - markerOffset;
+                assertThat(method.getParameterCount(), greaterThanOrEqualTo(1));
+                final Class<?>[] parameterTypes = method.getParameterTypes();
+                int markerOffset = parameterTypes[0].equals(Marker.class) ? 1 : 0;
+                int paramLength = parameterTypes.length - markerOffset;
                 if (method.isVarArgs()) {
                     assertEquals(2, paramLength);
-                    assertEquals(String.class, method.getParameterTypes()[markerOffset]);
-                    assertThat(method.getParameterTypes()[markerOffset + 1], is(oneOf(Object[].class, Supplier[].class)));
+                    assertEquals(String.class, parameterTypes[markerOffset]);
+                    assertThat(parameterTypes[markerOffset + 1], is(oneOf(Object[].class, Supplier[].class)));
                 } else {
-                    assertThat(method.getParameterTypes()[markerOffset], is(oneOf(Message.class, MessageSupplier.class,
+                    assertThat(parameterTypes[markerOffset], is(oneOf(Message.class, MessageSupplier.class,
                         CharSequence.class, Object.class, String.class, Supplier.class)));
 
                     if (paramLength == 2) {
-                        assertThat(method.getParameterTypes()[markerOffset + 1], is(oneOf(Throwable.class, Object.class)));
-                        if (method.getParameterTypes()[markerOffset + 1].equals(Object.class)) {
-                            assertEquals(String.class, method.getParameterTypes()[markerOffset]);
+                        assertThat(parameterTypes[markerOffset + 1], is(oneOf(Throwable.class, Object.class)));
+                        if (parameterTypes[markerOffset + 1].equals(Object.class)) {
+                            assertEquals(String.class, parameterTypes[markerOffset]);
                         }
                     }
                     if (paramLength > 2) {
-                        assertEquals(String.class, method.getParameterTypes()[markerOffset]);
+                        assertEquals(String.class, parameterTypes[markerOffset]);
                         assertThat(paramLength, lessThanOrEqualTo(11));
                         for (int i = 1; i < paramLength; i++) {
-                            assertEquals(Object.class, method.getParameterTypes()[markerOffset + i]);
+                            assertEquals(Object.class, parameterTypes[markerOffset + i]);
                         }
                     }
                 }
@@ -115,16 +116,17 @@ public void testLoggerUsageCheckerCompatibilityWithLog4j2Logger() throws NoSuchM
         }
 
         for (Constructor<?> constructor : ParameterizedMessage.class.getConstructors()) {
-            assertThat(constructor.getParameterTypes().length, greaterThanOrEqualTo(2));
-            assertEquals(String.class, constructor.getParameterTypes()[0]);
-            assertThat(constructor.getParameterTypes()[1], is(oneOf(String[].class, Object[].class, Object.class)));
-
-            if (constructor.getParameterTypes().length > 2) {
-                assertEquals(3, constructor.getParameterTypes().length);
-                if (constructor.getParameterTypes()[1].equals(Object.class)) {
-                    assertEquals(Object.class, constructor.getParameterTypes()[2]);
+            assertThat(constructor.getParameterCount(), greaterThanOrEqualTo(2));
+            final Class<?>[] parameterTypes = constructor.getParameterTypes();
+            assertEquals(String.class, parameterTypes[0]);
+            assertThat(parameterTypes[1], is(oneOf(String[].class, Object[].class, Object.class)));
+
+            if (parameterTypes.length > 2) {
+                assertEquals(3, parameterTypes.length);
+                if (parameterTypes[1].equals(Object.class)) {
+                    assertEquals(Object.class, parameterTypes[2]);
                 } else {
-                    assertEquals(Throwable.class, constructor.getParameterTypes()[2]);
+                    assertEquals(Throwable.class, parameterTypes[2]);
                 }
             }
         }
diff --git a/test/telemetry/build.gradle b/test/telemetry/build.gradle
new file mode 100644
index 0000000000000..ca523a9204f4c
--- /dev/null
+++ b/test/telemetry/build.gradle
@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+apply plugin: 'opensearch.build'
+apply plugin: 'opensearch.publish'
+
+dependencies {
+  api project(":libs:opensearch-core")
+  api project(":libs:opensearch-common")
+  api project(":libs:opensearch-telemetry")
+}
+
+tasks.named('forbiddenApisMain').configure {
+  //package does not depend on core, so only jdk signatures should be checked
+  replaceSignatureFiles 'jdk-signatures'
+}
+
+test.enabled = false
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpan.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpan.java
new file mode 100644
index 0000000000000..c5d179f6412a8
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpan.java
@@ -0,0 +1,205 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import org.opensearch.telemetry.tracing.AbstractSpan;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanCreationContext;
+import org.opensearch.telemetry.tracing.SpanKind;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.function.Supplier;
+
+/**
+ * MockSpan for testing and strict check validations. Not to be used for production cases.
+ */
+public class MockSpan extends AbstractSpan {
+    private final SpanProcessor spanProcessor;
+    private final Map<String, Object> metadata;
+    private final String traceId;
+    private final String spanId;
+    private boolean hasEnded;
+    private final Long startTime;
+    private Long endTime;
+    private final SpanKind spanKind;
+
+    private final Object lock = new Object();
+
+    private static final Supplier<Random> randomSupplier = ThreadLocalRandom::current;
+
+    /**
+     * Base Constructor.
+     *
+     * @param spanCreationContext      Span Creation context.
+     * @param parentSpan    Parent Span
+     * @param spanProcessor Span Processor
+     */
+    public MockSpan(SpanCreationContext spanCreationContext, Span parentSpan, SpanProcessor spanProcessor) {
+        this(
+            spanCreationContext.getSpanName(),
+            parentSpan,
+            parentSpan != null ? parentSpan.getTraceId() : IdGenerator.generateTraceId(),
+            IdGenerator.generateSpanId(),
+            spanProcessor,
+            spanCreationContext.getAttributes(),
+            SpanKind.INTERNAL
+        );
+    }
+
+    /**
+     * Constructor with traceId and SpanIds
+     *
+     * @param spanName      Span Name
+     * @param parentSpan    Parent Span
+     * @param traceId       Trace ID
+     * @param spanId        Span ID
+     * @param spanProcessor Span Processor
+     * @param attributes    attributes
+     * @param spanKind      type of span.
+     */
+    public MockSpan(
+        String spanName,
+        Span parentSpan,
+        String traceId,
+        String spanId,
+        SpanProcessor spanProcessor,
+        Attributes attributes,
+        SpanKind spanKind
+    ) {
+        super(spanName, parentSpan);
+        this.spanProcessor = spanProcessor;
+        this.metadata = new HashMap<>();
+        this.traceId = traceId;
+        this.spanId = spanId;
+        this.startTime = System.nanoTime();
+        if (attributes != null) {
+            this.metadata.putAll(attributes.getAttributesMap());
+        }
+        this.spanKind = spanKind;
+    }
+
+    @Override
+    public void endSpan() {
+        synchronized (lock) {
+            if (hasEnded) {
+                return;
+            }
+            endTime = System.nanoTime();
+            hasEnded = true;
+        }
+        spanProcessor.onEnd(this);
+    }
+
+    @Override
+    public void addAttribute(String key, String value) {
+        putMetadata(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Long value) {
+        putMetadata(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Double value) {
+        putMetadata(key, value);
+    }
+
+    @Override
+    public void addAttribute(String key, Boolean value) {
+        putMetadata(key, value);
+    }
+
+    @Override
+    public void addEvent(String event) {
+        putMetadata(event, null);
+    }
+
+    private void putMetadata(String key, Object value) {
+        metadata.put(key, value);
+    }
+
+    @Override
+    public String getTraceId() {
+        return traceId;
+    }
+
+    @Override
+    public String getSpanId() {
+        return spanId;
+    }
+
+    /**
+     * Returns whether the span is ended or not.
+     * @return span end status.
+     */
+    public boolean hasEnded() {
+        synchronized (lock) {
+            return hasEnded;
+        }
+    }
+
+    /**
+     * Returns the start time of the span.
+     * @return start time of the span.
+     */
+    public Long getStartTime() {
+        return startTime;
+    }
+
+    /**
+     * Returns the start time of the span.
+     * @return end time of the span.
+     */
+    public Long getEndTime() {
+        return endTime;
+    }
+
+    public void setError(Exception exception) {
+        if (exception != null) {
+            putMetadata("ERROR", exception.getMessage());
+        }
+    }
+
+    private static class IdGenerator {
+        private static String generateSpanId() {
+            long id = randomSupplier.get().nextLong();
+            return Long.toHexString(id);
+        }
+
+        private static String generateTraceId() {
+            long idHi = randomSupplier.get().nextLong();
+            long idLo = randomSupplier.get().nextLong();
+            long result = idLo | (idHi << 32);
+            return Long.toHexString(result);
+        }
+
+    }
+
+    /**
+     * Returns attribute.
+     * @param key key
+     * @return value
+     */
+    public Object getAttribute(String key) {
+        return metadata.get(key);
+    }
+
+    /**
+     * Returns the attributes as map.
+     * @return returns the attributes map.
+     */
+    public Map<String, Object> getAttributes() {
+        return metadata;
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpanData.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpanData.java
new file mode 100644
index 0000000000000..0658a6421f3f3
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockSpanData.java
@@ -0,0 +1,195 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import java.util.Arrays;
+import java.util.Map;
+
+/**
+ * MockSpanData model for storing Telemetry information for testing.
+ */
+public class MockSpanData {
+
+    /**
+     * MockSpanData constructor with spanID, parentSpanID, traceID, startEpochNanos, endEpochNanos, hasEnded params.
+     *
+     * @param spanID spanID
+     * @param parentSpanID spanID of the parentSpan
+     * @param traceID traceID of the request
+     * @param startEpochNanos startTime of span in epochNanos
+     * @param endEpochNanos endTime of span in epochNanos
+     * @param hasEnded value if the span is closed
+     * @param spanName Name of the span emitted
+     * @param attributes span attributes
+     */
+    public MockSpanData(
+        String spanID,
+        String parentSpanID,
+        String traceID,
+        long startEpochNanos,
+        long endEpochNanos,
+        boolean hasEnded,
+        String spanName,
+        Map<String, Object> attributes
+    ) {
+        this.spanID = spanID;
+        this.traceID = traceID;
+        this.parentSpanID = parentSpanID;
+        this.startEpochNanos = startEpochNanos;
+        this.endEpochNanos = endEpochNanos;
+        this.hasEnded = hasEnded;
+        this.spanName = spanName;
+        this.attributes = attributes;
+    }
+
+    /**
+     * MockSpanData constructor with spanID, parentSpanID, traceID, startEpochNanos, hasEnded and spanName params.
+     *
+     * @param spanID spanID
+     * @param parentSpanID spanID of the parentSpan
+     * @param traceID traceID of the request
+     * @param startEpochNanos startTime of span in epochNanos
+     * @param hasEnded value if the span is closed
+     * @param spanName Name of the span emitted
+     * @param stackTrace StackTrace to debug the problematic span
+     * @param attributes span attributes
+     */
+    public MockSpanData(
+        String spanID,
+        String parentSpanID,
+        String traceID,
+        long startEpochNanos,
+        boolean hasEnded,
+        String spanName,
+        StackTraceElement[] stackTrace,
+        Map<String, Object> attributes
+    ) {
+        this.spanID = spanID;
+        this.traceID = traceID;
+        this.parentSpanID = parentSpanID;
+        this.startEpochNanos = startEpochNanos;
+        this.hasEnded = hasEnded;
+        this.spanName = spanName;
+        this.stackTrace = stackTrace;
+        this.attributes = attributes;
+    }
+
+    private final String spanID;
+    private final String parentSpanID;
+    private final String traceID;
+
+    private String spanName;
+    private final long startEpochNanos;
+    private long endEpochNanos;
+    private boolean hasEnded;
+    private Map<String, Object> attributes;
+
+    private StackTraceElement[] stackTrace;
+
+    /**
+     * Returns SpanID.
+     */
+    public String getSpanID() {
+        return spanID;
+    }
+
+    /**
+     * Returns ParentSpanID.
+     */
+    public String getParentSpanID() {
+        return parentSpanID;
+    }
+
+    /**
+     * Returns TraceID.
+     */
+    public String getTraceID() {
+        return traceID;
+    }
+
+    /**
+     * Returns hasEnded.
+     */
+    public boolean isHasEnded() {
+        return hasEnded;
+    }
+
+    /**
+     * Returns EndEpochNanos for a span.
+     */
+    public long getEndEpochNanos() {
+        return endEpochNanos;
+    }
+
+    /**
+     * Returns StartEpochNanos for a span.
+     */
+    public long getStartEpochNanos() {
+        return startEpochNanos;
+    }
+
+    /**
+     * Returns StackTrace for a span.
+     */
+    public StackTraceElement[] getStackTrace() {
+        return stackTrace;
+    }
+
+    /**
+     * Sets EndEpochNanos for a span.
+     * @param endEpochNanos endtime in epoch nanos
+     */
+    public void setEndEpochNanos(long endEpochNanos) {
+        this.endEpochNanos = endEpochNanos;
+    }
+
+    /**
+     * Sets hasEnded for a span.
+     * @param hasEnded hasEnded value if span is closed.
+     */
+    public void setHasEnded(boolean hasEnded) {
+        this.hasEnded = hasEnded;
+    }
+
+    /**
+     * Returns the attributes
+     * @return returns the attributes map.
+     */
+    public Map<String, Object> getAttributes() {
+        return attributes;
+    }
+
+    @Override
+    public String toString() {
+        return "MockSpanData{"
+            + "spanID='"
+            + spanID
+            + '\''
+            + ", parentSpanID='"
+            + parentSpanID
+            + '\''
+            + ", traceID='"
+            + traceID
+            + '\''
+            + ", spanName='"
+            + spanName
+            + '\''
+            + ", startEpochNanos="
+            + startEpochNanos
+            + ", endEpochNanos="
+            + endEpochNanos
+            + ", hasEnded="
+            + hasEnded
+            + ", attributes="
+            + attributes
+            + ", stackTrace="
+            + Arrays.toString(stackTrace)
+            + '}';
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingContextPropagator.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingContextPropagator.java
new file mode 100644
index 0000000000000..6d0cd6d0b1290
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingContextPropagator.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import org.opensearch.core.common.Strings;
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanKind;
+import org.opensearch.telemetry.tracing.TracingContextPropagator;
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.BiConsumer;
+import java.util.stream.Collectors;
+
+/**
+ * Mock {@link TracingContextPropagator} to persist the span for internode communication.
+ */
+public class MockTracingContextPropagator implements TracingContextPropagator {
+
+    private static final String TRACE_PARENT = "traceparent";
+    private static final String SEPARATOR = "~";
+    private final SpanProcessor spanProcessor;
+
+    /**
+     * Constructor
+     * @param spanProcessor span processor.
+     */
+    public MockTracingContextPropagator(SpanProcessor spanProcessor) {
+        this.spanProcessor = spanProcessor;
+    }
+
+    @Override
+    public Optional<Span> extract(Map<String, String> props) {
+        String value = props.get(TRACE_PARENT);
+        if (value != null) {
+            String[] values = value.split(SEPARATOR);
+            String traceId = values[0];
+            String spanId = values[1];
+            return Optional.of(new MockSpan(null, null, traceId, spanId, spanProcessor, Attributes.EMPTY, SpanKind.INTERNAL));
+        } else {
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public Optional<Span> extractFromHeaders(Map<String, List<String>> headers) {
+        if (headers != null) {
+            Map<String, String> convertedHeader = headers.entrySet()
+                .stream()
+                .collect(Collectors.toMap(Map.Entry::getKey, e -> Strings.collectionToCommaDelimitedString(e.getValue())));
+            return extract(convertedHeader);
+        } else {
+            return Optional.empty();
+        }
+
+    }
+
+    @Override
+    public void inject(Span currentSpan, BiConsumer<String, String> setter) {
+        if (currentSpan instanceof MockSpan) {
+            String traceId = currentSpan.getTraceId();
+            String spanId = currentSpan.getSpanId();
+            String traceParent = String.format(Locale.ROOT, "%s%s%s", traceId, SEPARATOR, spanId);
+            setter.accept(TRACE_PARENT, traceParent);
+        }
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingTelemetry.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingTelemetry.java
new file mode 100644
index 0000000000000..39817a208bd18
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/MockTracingTelemetry.java
@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.telemetry.tracing.SpanCreationContext;
+import org.opensearch.telemetry.tracing.TracingContextPropagator;
+import org.opensearch.telemetry.tracing.TracingTelemetry;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Mock {@link TracingTelemetry} implementation for testing.
+ */
+public class MockTracingTelemetry implements TracingTelemetry {
+
+    private final SpanProcessor spanProcessor = new StrictCheckSpanProcessor();
+    private final AtomicBoolean shutdown = new AtomicBoolean(false);
+
+    /**
+     * Base constructor.
+     */
+    public MockTracingTelemetry() {}
+
+    @Override
+    public Span createSpan(SpanCreationContext spanCreationContext, Span parentSpan) {
+        Span span = new MockSpan(spanCreationContext, parentSpan, spanProcessor);
+        if (shutdown.get() == false) {
+            spanProcessor.onStart(span);
+        }
+        return span;
+    }
+
+    @Override
+    public TracingContextPropagator getContextPropagator() {
+        return new MockTracingContextPropagator(spanProcessor);
+    }
+
+    @Override
+    public void close() {
+        shutdown.set(true);
+    }
+
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/SpanProcessor.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/SpanProcessor.java
new file mode 100644
index 0000000000000..cb9d0dbd428e4
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/SpanProcessor.java
@@ -0,0 +1,28 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import org.opensearch.telemetry.tracing.Span;
+
+/**
+ * Processes the span and can perform any action on the span start and end.
+ */
+public interface SpanProcessor {
+    /**
+     * Logic to be executed on span start.
+     * @param span span which is starting.
+     */
+    void onStart(Span span);
+
+    /**
+     * Logic to be executed on span end.
+     * @param span span which is ending.
+     */
+    void onEnd(Span span);
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/StrictCheckSpanProcessor.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/StrictCheckSpanProcessor.java
new file mode 100644
index 0000000000000..f7ebb3ee18a9b
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/StrictCheckSpanProcessor.java
@@ -0,0 +1,87 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import org.opensearch.telemetry.tracing.Span;
+import org.opensearch.test.telemetry.tracing.validators.AllSpansAreEndedProperly;
+import org.opensearch.test.telemetry.tracing.validators.AllSpansHaveUniqueId;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Strict check span processor to validate the spans.
+ */
+public class StrictCheckSpanProcessor implements SpanProcessor {
+    /**
+     * Base constructor.
+     */
+    public StrictCheckSpanProcessor() {}
+
+    private static Map<String, MockSpanData> spanMap = new ConcurrentHashMap<>();
+
+    @Override
+    public void onStart(Span span) {
+        spanMap.put(span.getSpanId(), toMockSpanData(span));
+    }
+
+    @Override
+    public void onEnd(Span span) {
+        MockSpanData spanData = spanMap.get(span.getSpanId());
+        // Setting EndEpochTime and HasEnded value to true on completion of span.
+        if (spanData != null) {
+            spanData.setEndEpochNanos(System.nanoTime());
+            spanData.setHasEnded(true);
+        }
+    }
+
+    /**
+     * Return list of mock span data at any point of time.
+     */
+    public List<MockSpanData> getFinishedSpanItems() {
+        return new ArrayList<>(spanMap.values());
+    }
+
+    private MockSpanData toMockSpanData(Span span) {
+        String parentSpanId = (span.getParentSpan() != null) ? span.getParentSpan().getSpanId() : "";
+        MockSpanData spanData = new MockSpanData(
+            span.getSpanId(),
+            parentSpanId,
+            span.getTraceId(),
+            System.nanoTime(),
+            false,
+            span.getSpanName(),
+            Thread.currentThread().getStackTrace(),
+            (span instanceof MockSpan) ? ((MockSpan) span).getAttributes() : Map.of()
+        );
+        return spanData;
+    }
+
+    /**
+     * Ensures the strict check succeeds for all the spans.
+     */
+    public static void validateTracingStateOnShutdown() {
+        List<MockSpanData> spanData = new ArrayList<>(spanMap.values());
+        if (spanData.size() != 0) {
+            TelemetryValidators validators = new TelemetryValidators(
+                Arrays.asList(new AllSpansAreEndedProperly(), new AllSpansHaveUniqueId())
+            );
+            try {
+                validators.validate(spanData, 1);
+            } catch (Error e) {
+                spanMap.clear();
+                throw e;
+            }
+        }
+
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TelemetryValidators.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TelemetryValidators.java
new file mode 100644
index 0000000000000..8d8c18fb9ef6b
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TelemetryValidators.java
@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * TelemetryValidators for running validate on all applicable span Validator classes.
+ */
+public class TelemetryValidators {
+    private List<TracingValidator> validators;
+
+    /**
+     * Base constructor.
+     * @param validators list of validators applicable
+     */
+    public TelemetryValidators(List<TracingValidator> validators) {
+        this.validators = validators;
+    }
+
+    /**
+     * calls validate of all validators and throws exception in case of error.
+     * @param spans List of spans emitted
+     * @param requests Request can be indexing/search call
+     */
+    public void validate(List<MockSpanData> spans, int requests) {
+        Map<String, List<MockSpanData>> problematicSpansMap = new HashMap<>();
+        for (TracingValidator validator : this.validators) {
+            List<MockSpanData> problematicSpans = validator.validate(spans, requests);
+            if (!problematicSpans.isEmpty()) {
+                problematicSpansMap.put(validator.getClass().getName(), problematicSpans);
+            }
+        }
+        if (!problematicSpansMap.isEmpty()) {
+            AssertionError error = new AssertionError(printProblematicSpansMap(problematicSpansMap));
+            throw error;
+        }
+    }
+
+    private String printProblematicSpansMap(Map<String, List<MockSpanData>> spanMap) {
+        StringBuilder sb = new StringBuilder();
+        for (var entry : spanMap.entrySet()) {
+            sb.append("SpanData validation failed for validator " + entry.getKey());
+            sb.append("/n");
+            for (MockSpanData span : entry.getValue()) {
+                sb.append(span.toString());
+            }
+        }
+        return sb.toString();
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TracingValidator.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TracingValidator.java
new file mode 100644
index 0000000000000..8b125c7e97cf7
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/TracingValidator.java
@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing;
+
+import java.util.List;
+
+/**
+ * Performs validations on traces emitted.
+ */
+public interface TracingValidator {
+    /**
+     * Validates spanData and return list of problematic spans.
+     * @param spans spans emitted at any point of time.
+     * @param requests requests can be search/index calls.
+     */
+    public List<MockSpanData> validate(List<MockSpanData> spans, int requests);
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/package-info.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/package-info.java
new file mode 100644
index 0000000000000..83e2b4035acbf
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base opensearch package. */
+package org.opensearch.test.telemetry.tracing;
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansAreEndedProperly.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansAreEndedProperly.java
new file mode 100644
index 0000000000000..483ed98de9474
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansAreEndedProperly.java
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing.validators;
+
+import org.opensearch.test.telemetry.tracing.MockSpanData;
+import org.opensearch.test.telemetry.tracing.TracingValidator;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * AllSpansAreEndedProperly validator to check if all spans are closed properly.
+ */
+public class AllSpansAreEndedProperly implements TracingValidator {
+
+    /**
+     * Base Constructor
+     */
+    public AllSpansAreEndedProperly() {}
+
+    /**
+     * validates if all spans emitted have hasEnded attribute as true.
+     * @param spans spans emitted.
+     * @param requests requests for e.g. search/index call
+     */
+    @Override
+    public List<MockSpanData> validate(List<MockSpanData> spans, int requests) {
+        List<MockSpanData> problematicSpans = spans.stream().filter(s -> s.isHasEnded() == false).collect(Collectors.toList());
+        return problematicSpans;
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansHaveUniqueId.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansHaveUniqueId.java
new file mode 100644
index 0000000000000..a64dd047b68f5
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/AllSpansHaveUniqueId.java
@@ -0,0 +1,46 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing.validators;
+
+import org.opensearch.test.telemetry.tracing.MockSpanData;
+import org.opensearch.test.telemetry.tracing.TracingValidator;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * AllSpansHaveUniqueId validator checks if all spans emitted have a unique spanID.
+ */
+public class AllSpansHaveUniqueId implements TracingValidator {
+
+    /**
+     * Base Constructor
+     */
+    public AllSpansHaveUniqueId() {}
+
+    /**
+     * validates if all spans emitted have a unique spanID
+     * @param spans spans emitted.
+     * @param requests requests for e.g. search/index call
+     */
+    @Override
+    public List<MockSpanData> validate(List<MockSpanData> spans, int requests) {
+        List<MockSpanData> problematicSpans = new ArrayList<>();
+        Set<String> set = new HashSet<>();
+        for (MockSpanData span : spans) {
+            if (set.contains(span.getSpanID())) {
+                problematicSpans.add(span);
+            }
+            set.add(span.getSpanID());
+        }
+        return problematicSpans;
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/NumberOfTraceIDsEqualToRequests.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/NumberOfTraceIDsEqualToRequests.java
new file mode 100644
index 0000000000000..5fe268a8f0581
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/NumberOfTraceIDsEqualToRequests.java
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing.validators;
+
+import org.opensearch.telemetry.tracing.attributes.Attributes;
+import org.opensearch.test.telemetry.tracing.MockSpanData;
+import org.opensearch.test.telemetry.tracing.TracingValidator;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * NumberOfTraceIDsEqualToRequests checks if number of unique traceIDs are equal to unique requests.
+ */
+public class NumberOfTraceIDsEqualToRequests implements TracingValidator {
+
+    private static final String FILTERING_ATTRIBUTE = "action";
+    private final Attributes attributes;
+
+    /**
+     * Constructor.
+     * @param attributes attributes.
+     */
+    public NumberOfTraceIDsEqualToRequests(Attributes attributes) {
+        this.attributes = attributes;
+    }
+
+    /**
+     * validates if all spans emitted for a particular request have same traceID.
+     * @param spans spans emitted.
+     * @param requests requests for e.g. search/index call
+     */
+    @Override
+    public List<MockSpanData> validate(List<MockSpanData> spans, int requests) {
+        Set<String> totalTraceIDs = spans.stream()
+            .filter(span -> isMatchingSpan(span))
+            .map(MockSpanData::getTraceID)
+            .collect(Collectors.toSet());
+        List<MockSpanData> problematicSpans = new ArrayList<>();
+        if (totalTraceIDs.size() != requests) {
+            problematicSpans.addAll(spans);
+        }
+        return problematicSpans;
+    }
+
+    private boolean isMatchingSpan(MockSpanData mockSpanData) {
+        if (attributes.getAttributesMap().isEmpty()) {
+            return true;
+        } else {
+            return Objects.equals(
+                mockSpanData.getAttributes().get(FILTERING_ATTRIBUTE),
+                attributes.getAttributesMap().get(FILTERING_ATTRIBUTE)
+            );
+        }
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/TotalRootSpansEqualToRequests.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/TotalRootSpansEqualToRequests.java
new file mode 100644
index 0000000000000..80703ccf479ef
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/TotalRootSpansEqualToRequests.java
@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.test.telemetry.tracing.validators;
+
+import org.opensearch.test.telemetry.tracing.MockSpanData;
+import org.opensearch.test.telemetry.tracing.TracingValidator;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * TotalRootSpansEqualToRequests validator to check sanity on total parent spans.
+ */
+public class TotalRootSpansEqualToRequests implements TracingValidator {
+
+    /**
+     * Base Constructor
+     */
+    public TotalRootSpansEqualToRequests() {}
+
+    /**
+     * validates if total parent spans are equal to number of requests.
+     * @param spans spans emitted.
+     * @param requests requests for e.g. search/index call
+     */
+    @Override
+    public List<MockSpanData> validate(List<MockSpanData> spans, int requests) {
+        List<MockSpanData> problematicSpans = new ArrayList<>();
+        List<MockSpanData> totalParentSpans = spans.stream().filter(s -> s.getParentSpanID().isEmpty()).collect(Collectors.toList());
+        if (totalParentSpans.size() != requests) {
+            problematicSpans.addAll(totalParentSpans);
+        }
+        return problematicSpans;
+    }
+}
diff --git a/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/package-info.java b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/package-info.java
new file mode 100644
index 0000000000000..ef1b1493198f0
--- /dev/null
+++ b/test/telemetry/src/main/java/org/opensearch/test/telemetry/tracing/validators/package-info.java
@@ -0,0 +1,10 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/** Base tracing validators package. */
+package org.opensearch.test.telemetry.tracing.validators;